Lobster Bibliography obtained from scanning WOS (300) and NLM (450) for papers with Homarus in title abstract or keywords as of I-18-2000
Abdennour, C. (1997). Copper, zinc and haemocyanin concentrations in four caridean decapods (Crustacea): size relationships. Hydrobiologia 346, 1-9.
The relationships between individual dry weight and body content of the essential metals copper and zinc and of the respiratory pigment haemocyanin have been investigated in four British species of caridean decapod crustaceans, Palaemon elegans, Palaemon longirostris, Palaemonetes varians and Crangon crangon. Also considered were the body concentrations of soluble copper and copper associated with haemocyanin. These decapods regulate total body concentrations of copper and zinc to approximately constant levels which can vary interspecifically. An attempt is made to interpret these regulated concentrations in terms of essential requirements for the metals in the physiological functioning of haemocyanin, the body concentration of which varies interspecifically and intraspecifically with environmental variables.
Abdu, U., Takac, P., Laufer, H., and Sagi, A. (1998). Effect of methyl farnesoate on late larval development and metamorphosis in the prawn Macrobrachium rosenbergii (Decapoda, Palaemonidae): A juvenoid-like effect? Biological Bulletin 195, 112-119.
Methyl farnesoate (MF), the unepoxidated form of insect juvenile hormone III, was detected in larvae of the freshwater prawn Macrobrachium rosenbergii, which metamorphose to post- larvae following Ii larval stages. The possible role of MF as a morphogen was studied by administering the compound to M. rosenbergii larvae via an Artemia vector. Higher MF levels caused earlier retardation of late larval growth, and the highest dose retarded larval development. Furthermore, MF significantly affected the patterns of metamorphosis and the appearance of intermediate individuals exhibiting both larval and post-larval morphology and behavior. Three intermediate types were defined, two of which were found only at the MF- treated groups and one that was exclusive to the higher dose treatments. The relative abundance of intermediate specimens increased from 2% in the control to 32% in the high MF concentration, which suggests that MF has a juvenoid-like effect in this decapod crustacean.
Abdu, U., Takac, P., Yehezkel, G., Chayoth, R., and Sagi, A. (1998). Administration of methyl farnesoate through the artemia vector, and its effect on Macrobrachium rosenbergii larvae. Israeli Journal of Aquaculture-Bamidgeh 50, 73-81.
We have developed a method for the administration of juvenile hormone-like compounds into crustacean larvae through a live food vector, the brine shrimp Artemia, commonly used in prawn aquaculture. In crustaceans, the only juvenile hormone-like compound found to date is methyl farnesoate (MF), the unepoxidated form of insect juvenile hormone III. Since MF is hydrophobic, its administration to crustacean larvae in aqueous culture media is problematic. Accumulation of the compound in Artemia cultured in a lipid medium enriched with MF was verified by HPLC, which demonstrated the stability of the compound within the vector. Artemis that were cultured in media containing [H-3]MF accumulated 7.27% of the total radioactivity added. About 0.065% of the total radioactivity added was found in 20 M. rosenbergii larvae fed on the enriched Artemia. MF freshly administered daily to M. rosenbergii larvae caused a retardation of larval growth, manifested by carapace length. In addition, MF altered larval development by retarding the stage specific morphological features between larval stages 5 and 9. This new method for administering MF may facilitate further studies examining the regulatory role of MF in crustacean larval development and metamorphosis. It may also be instrumental in the administration of other hydrophobic drugs into crustacean larvae.
Abel, C. A., Campbell, P. A., VanderWall, J., and Hartman, A. L. (1984). Studies on the structure and carbohydrate binding properties of lobster agglutinin 1 (LAg1), a sialic acid-binding lectin. Prog Clin Biol Res 157, 103-14.
Lobster agglutinin 1 (LAg 1) was isolated from the hemolymph of the American lobster (Homarus americanus) by a sequential combination of ammonium sulfate precipitation, preparative starch block electrophoresis, gel filtration and affinity chromatography on Sepharose-Fetuin and Sepharose-Colominic acid columns. Two types of protomeric structures with molecular weights of 700 and 500 Kilodaltons respectively were isolated. These molecules are composed of noncovalently held subunits with a molecular weight of 70 Kilodaltons. Analysis of preparations by double immunodiffusion, polyacrylamide gel electrophoresis and isoelectrofocusing indicates that the LAg 1 obtained was a single molecular species. Hemagglutination inhibition experiments indicated that the best inhibitors were bovine mucin, glycophorin, fetuin and human IgM in that order. The desialylated forms of some of these proteins still bound lectin, although to a lesser degree than their intact sialylated counterparts. Affinity chromatography experiments indicated that LAg 1 binds to N- acetylneuraminic acid, N-acetylglucosamine and N-acetylgalactosamine. LAg 1 does not contain sialic acid nor neuraminidase activity: oligosaccharides associated with it appear to be either of the oligomannosyl or biantennary type. The sialic acid binding specificity of this lectin was used to separate immature mouse thymocytes (low sialic acid content) from mature thymocytes (high sialic acid content).
Abgrall, P., Rangeley, R. W., Burridge, L. E., and Lawton, P. (2000). Sublethal effects of azamethiphos on shelter use by juvenile lobsters (Homarus americanus). Aquaculture 181, 1-10.
The use of pesticides to treat sea lice infestations in aquaculture may have negative impacts on non-target organisms such as the American lobster (Homarus americanus). Juvenile lobsters spend most of their time in shelter to avoid predation. This study examined: (1) whether the organophosphate pesticide azamethiphos affected shelter use by juvenile lobsters; (2) whether leaving shelter was a form of azamethiphos avoidance; and (3) whether azamethiphos affected shelter re-entry. The experiments were performed on juvenile lobsters (6.5-8 mm carapace length) in individual aquaria with an artificial shelter placed on a sand substrate. Azamethiphos concentrations of 0, 100, 500 and 1000 mu g l(-1) were used. Ten-minute short-term pulsed exposures to azamethiphos mimicking field conditions resulted in no shelter exits or lobster deaths. Under continuous exposure to azamethiphos, all lobsters left their shelters and the time to shelter exit and death decreased with increasing azamethiphos concentration. Survival of lobsters placed in fresh seawater following shelter exit was 100% for the 100 mu g l(-1) treatment, 50% for the 500 mu g l(-1) treatment and 33% for the 1000 mu g l(-1) treatment. Time to re-enter the shelter following exposure to azamethiphos was significantly shorter than the control for lobsters exposed to 100 mu g l(-1) and significantly longer than the control for lobsters exposed to 1000 mu g l(-1). Shelter exit appears to be a form of avoidance behavior to high concentrations of azamethiphos. At concentrations used by the aquaculture industry (100 mu g l(-1) and short exposure times), azamethiphos would not affect lobster shelter use. However, if the concentration or exposure time increased, mortality could occur directly due to this pesticide or indirectly as a consequence of leaving shelter. (C) 2000 Elsevier Science B.V. All rights reserved.
Abrunhosa, F. A., and Kittaka, J. (1997). Effect of starvation on the first larvae of Homarus americanus (Decapoda, Nephropidae) and phyllosomas of Jasus verreauxi and J-edwardsii (Decapoda, Palinuridae). Bulletin of Marine Science 61, 73-80.
Food is one of the important factors controlling decapod larval culture, however, little is known about the effect of the starvation regimen on the physiological condition of the larvae. In the present study, the influence of starvation upon survival rate and the intermolt period was observed in the first instar of the American lobster, Homarus americanus, the first instars of phyllosomas of the red rock lobster, Jasus edwardsii, and the green rock lobster, J. verreauxi. Larvae were reared in receptacles of 150 ml capacity filled with sea water and submitted to two feeding regimens: larvae were submitted to an initial period of starvation and larvae were submitted to an initial period of feeding. Larvae of H. americanus were cultured individually at 17-18 degrees C, while phyllosomas were cultured at five larvae per receptacle at temperatures of 19-22 degrees C and 16-17 degrees C for J. edwardsii and J. verreauxi. respectively. No larvae succeeded in molting if completely starved or if they were fed after a prolonged starvation period. However, the species showed a period of tolerance before food was introduced. The average interval between the first day of feeding and the first day of molting was relatively constant within each species: about 4, 10 and 12 d for H. americanus, J. edwardsii and J. verreauxi, respectively. The starvation tolerance period (50% survival) averaged about 5, 4 and 8 d for these species, respectively. The interval between the ending of starvation and the initial molting period were roughly equivalent although it was shorter in H. americanus than in the Jasus species. The beginning of molting in each species was delayed in accordance with prolonged days of starvation. The feeding period that allowed at least 50% of the larvae to molt to the 2nd instar was 1, 5 and 7 d for these species, respectively. Molting in each species began after a rather constant intermolt period (5, 12, 13 d, respectively), regardless of the length of the initial feeding period. These results indicate that the first instar phyllosoma of these Jasus spp. are less tolerant of starvation and require a longer feeding period to molt compared to Homarus larvae.
Abrunhosa, F. A., and Kittaka, J. (1997). Morphological changes in the midgut, midgut gland and hindgut during the larval and postlarval development of the red king crab Paralithodes camtschaticus. Fisheries Science 63, 746-754.
Little alteration occurs in the midgut and hindgut during all zoea and in the early glaucothoe of Paralithodes camtschaticus, The gross morphology of the midgut gland is relatively simple. It is composed of one main and two secondary lobes. The anterior midgut caeca are present in the zoea and early glaucothoe, having histological characteristics similar to those found in the cells of the midgut gland lobes. On the contrary, the posterior caecum differentiated in the midgut of glaucothoe near the time of molting to the first juvenile. Large lipid droplets are accumulated during the zoeal instars in the medial portion of the midgut gland and anterior midgut caeca. A drastic change is observed in all digestive systems of the late phase of glaucothoe, The midgut maximally elongates and the anterior midgut caeca largely reduce. The posterior lobe elongates, extending up to the second and third abdominal segments. Most cells of the midgut gland of late glaucothoe decrease the previous Lipid droplets observed during the zoeal instars. It is proposed that these large amounts of lipids are used as an energy source during the non-feeding glaucothoe stage.
Ache, B. W. (1972). Amino acid receptors in the antennules of Homarus americanus. Comp Biochem Physiol A 42, 807-11.
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Acton, R. T., Weinheimer, P. F., and Evans, E. E. (1969). A bactericidal system in the lobster Homarus americanus. J Invertebr Pathol 13, 463-4.
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Adamczewska, A. M., and Morris, S. (1998). The functioning of the haemocyanin of the terrestrial Christmas Island red crab Gecarcoidea natalis and roles for organic modulators. Journal of Experimental Biology 201, 3233-3244.
Gecarcoidea natalis is a land crab that migrates annually several kilometres to breed. The O-2-binding properties of haemocyanin in G. natalis were investigated in vitro to test the idea that the O-2-binding properties of the haemocyanin of land crabs are not dependent on circulating modulators and to provide a model of haemocyanin functioning during exercise. The affinity of the haemocyanin for O-2 decreased with increasing temperature (change in the heat of oxygenation; Delta H=-59kJ mol(-1)). The haemocyanin of G, natalis apparently differs from that of other terrestrial crabs in showing haemocyanin O-2 modulation by both organic and inorganic molecules. Haemocyanin O-2-affinity,vas not affected by Mg2+ but was sensitive to changes in Ca2+ concentration (Delta logP(50)/Delta log[Ca]=- 0.61, where P-50 is the partial pressure of Oz required for half-maximal Oz binding), The Bohr factor was modest (phi=- 0.26+/-0.03, N=4, in whole haemolymph at 25 degrees C) and there was no specific effect of CO2 on the O-2-binding properties of the haemocyanin, An increase in urate concentration increased haemocyanin O-2-affinity, but the effect was linear (Delta logP(50)/Delta[urate]=-0.06) and not logarithmic as is the case in other species, The effect of L- lactate on the haemocyanin O-2-affinity in G. natalis was unique among the crustaceans, because an increase in L-lactate concentration decreased the haemocyanin O-2-affinity. The effect of L-lactate on haemocyanin O-2-affinity (Delta logP(50)/Delta log[lactate]) was time-dependent and decreased from a maximum of 0.044 on day 1 to 0.001 after 4 days of storage at 4 degrees C, The presence of an unknown dialysable and unstable factor in the haemolymph is postulated to explain the time-dependent effect of L-lactate on haemocyanin O-2- binding properties. Model oxygen equilibrium curves constructed for in vivo conditions showed that the reverse effect of L- lactate was advantageous by decreasing the O-2-affinity of the haemocyanin beyond that predicted by the Bohr shift alone and assisted in O-2 off-loading at the tissues. This effect of lactate can only provide an advantage if the gas-exchange organs maintain arterial O-2 loading and thus is dependent on lung function in land crabs and must have occurred coincident with the evolution of these other features.
Addison, J. T. (1997). Lobster stock assessment: report from a workshop; I. Marine and Freshwater Research 48, 941-944.
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Addison, J. T., and Bell, M. C. (1997). Simulation modelling of capture processes in trap fisheries for clawed lobsters. Marine and Freshwater Research 48, 1035-1044.
Lobster stock assessments are difficult because trap catch rates cannot be assumed to be proportional to abundance. A simulation model has been developed to consider the factors that might contribute to trap sampling bias. In the presence of trap saturation due to behavioural interactions at the trap, the model predicts an asymptotic relationship between catch and density and a decline in the variance:mean ratio of catch numbers per trap with density. A random or even distribution of lobsters among traps is predicted despite an initial aggregated distribution of lobsters on the seabed. Within the range of parameter values investigated, local depletion around the trap and decline in bait attractiveness had less influence than behavioural interactions on catch rates and the distribution of the catch among traps. All these results were, however, sensitive to assumptions made about the nature of lobster movement on the seabed. The results have implications for the use of catch data in assessing stock abundance, and as the pattern of model predictions is consistent with observed fisheries data, the model is likely to provide a useful framework for investigating capture processes in trap fisheries for crustaceans.
Aguilar, M. B., Falchetto, R., Shabanowitz, J., Hunt, D. F., and Huberman, A. (1996). Complete primary structure of the molt-inhibiting hormone (MIH) of the Mexican crayfish Procambarus bouvieri (Ortmann). Peptides 17, 367-74.
The amino acid sequence of MIH was elucidated by means of digestions with specific proteases, manual Edman degradation, and mass spectrometry. MIH consists of a 72-residue peptide chain (molecular mass 8322 Da) with six cysteines forming three disulfide bridges that connect residues 7-43, 23-39, and 26-52. It has blocked N- and C- termini and lacks tryptophan, histidine, and methionine. MIH shows striking similarity to the crustacean hyperglycemic hormone (CHH) isomorphs of Procambarus bouvieri (90% identity) and to the MIH from Homarus americanus (79% identity) and Penaeus vannamei (46% identity). It is also related to the MIH from Carcinus maenas (28% identity) and Callinectes sapidus (28% identity).
Ahearn, G. A., and Franco, P. (1990). Sodium and calcium share the electrogenic 2 Na(+)-1 H+ antiporter in crustacean antennal glands. Am J Physiol 259, F758-67.
Na uptake by short-circuited epithelial brush-border membrane vesicles of Atlantic lobster (Homarus americanus) antennal gland labyrinth was Cl independent, amiloride sensitive, and stimulated by a transmembrane H+ gradient [( H]i greater than [H]o; i is internal, o is external). Na influx (2.5-s uptake) was a sigmoidal function of [Na]o (25-400 mM) when pHi = 5.0 and pHo = 8.0 and followed the Hill equation for binding cooperatively [apparent maximal influx (Jmax) = 271 nmol.mg protein-1.s- 1, apparent affinity constant for Na (KNa) = 310 mM Na, and Hill coefficient (n) = 2.41]. Amiloride acted as a competitive inhibitor of Na binding to two external sites with markedly dissimilar apparent amiloride affinities (Ki1 = 14 microM; Ki2 = 1,340 mM). Electrogenic Na- H antiport by these vesicles was demonstrated by equilibrium-shift experiments in which an imposed transmembrane electrical potential difference was the only driving force for exchange. A transport stoichiometry of 2 Na to 1 H was demonstrated with the static-head technique in which a balance of driving forces was attained with 10:1 Na gradient and 100:1 H gradient. External Ca, like amiloride, was a strong competitive inhibitor of Na-H exchange, acting at two sites on the outer vesicular face with markedly different apparent divalent cation affinities (Ki1 = 20 microM; Ki2 = 500 microM). Ca-H exchange by electrogenic Na-H antiporter was demonstrated in complete absence of Na by use of an outward H gradient in presence and absence of amiloride. Both external amiloride (Ki1 = 70 microM; Ki2 = 500 microM) and Na (Ki1 = 12 mM; Ki2 = 380 mM) were competitive inhibitors of Ca-H exchange. These results suggest that the electrogenic 2 Na-1 H exchanger characterized for this crustacean epithelium may also have a role in organismic Ca balance.
Ahearn, G. A., Franco, P., and Clay, L. P. (1990). Electrogenic 2 Na+/1 H+ exchange in crustaceans. J Membr Biol 116, 215-26.
Hepatopancreatic brush border membrane vesicles of the freshwater prawn, Macrobrachium rosenbergii and the marine lobster, Homarus americanus exhibited 22Na uptake which was Cl-independent, amiloride sensitive, and stimulated by a transmembrane H gradient (Hi greater than Ho). Sodium influx by vesicles of both species were sigmoidal functions of [Na]o, yielding Hill coefficients that were not significantly different (P greater than 0.5) than 2.0. Estimations of half-saturation constants (KNa) were 82.2 mM (prawn) and 280.1 mM (lobster), suggesting a possible adaptation of this transporter to environmental salinity. Trans-stimulation and cis-inhibition experiments involving variable [H] suggested that the exchangers in both species possessed single internal cation binding sites (pK 6.5- 6.7) and two external cation binding sites (prawn, pK 4.0 and 5.7; lobster pK 3.5 and 6.1). Similar cis inhibition studies using amiloride as a competitive inhibitor of Na uptake supported the occurrence of dual external sites (prawn, Ki50 and 1520 microM; lobster Ki9 and 340 microM). Electrogenic Na/H exchange by vesicles from both crustaceans was demonstrated using equilibrium shift experiments where a transmembrane potential was used as the only driving force for the transport event. Transport stoichiometries of the antiporters were determined using Static Head analysis where driving forces for cation transfer were balanced using a 10:1 Na gradient, a 100:1 H gradient, and a stoichiometry of 2.0. These electrogenic 2 Na/1 H exchangers appear thermodynamically capable of generating sufficient gastric acidification for organismic digestive activities.
Ahearn, G. A., and Franco, P. (1993). Ca2+ transport pathways in brush-border membrane vesicles of crustacean antennal glands. Am J Physiol 264, R1206-13.
Calcium uptake by brush-border membrane vesicles of Atlantic lobster (Homarus americanus) kidneys (antennal glands) in independent experiments was stimulated by outwardly directed Na or H gradients. In the absence of external amiloride, 45Ca uptake was strongly stimulated by an outwardly directed Na gradient, and this stimulation was enhanced by the addition of an inside-negative membrane potential. External amiloride (2 mM) reduced 45Ca uptake sixfold and lowered sensitivity to membrane potential. 45Ca influx kinetics (2.5-s uptake) in the presence of an outwardly directed H gradient and inside-negative membrane potential were composed of three components: 1) an amiloride-sensitive carrier system, 2) an amiloride-insensitive carrier system, and 3) a verapamil- and membrane potential-sensitive process that may represent diffusional transfer through a calcium channel. It was concluded that 45Ca entry by the amiloride-sensitive process occurred by a previously described electrogenic 2 Na-1 H antiport mechanism [Ahearn, G., and L. Clay. Am. J. Physiol. 257 (Regulatory Integrative Comp. Physiol. 26): R484-R493, 1989; Am. J. Physiol. 259 (Renal Fluid Electrolyte Physiol. 28): F758-F767, 1990; Ahearn, G., P. Franco, and L. Clay. J. Membr. Biol. 116: 215-226, 1990]. 45Ca influx by the amiloride-insensitive mechanism occurred by an apparent electroneutral 1 Ca-2 Na exchange. Transport stoichiometry of the latter mechanism was tentatively established by experiments determining intravesicular Na binding properties and by its apparent lack of response to a membrane potential. At physiological Na, Ca, and H concentrations in the antennal gland lumen and epithelial cytosol, these three calcium transport pathways individually may make significant contributions to net calcium reabsorption to the blood.
Ahearn, G. A., Duerr, J. M., Zhuang, Z., Brown, R. J., Aslamkhan, A., and Killebrew, D. A. (1999). Ion transport processes of crustacean epithelial cells. Physiological and Biochemical Zoology 72, 1-18.
Epithelial cells of the gut, antennal glands, integument, and gills of crustaceans regulate the movements of ions into and across these structures and thereby influence the concentrations of ions in the hemolymph. Specific transport proteins serving cations and anions are found on apical and basolateral cell membranes of epithelia in these tissues. In recent years, a considerable research effort has been directed at elucidating their physiological and molecular properties and relating these characteristics to the overall biology of the organisms. Efforts to describe ion transport in crustaceans have focused on the membrane transfer properties of Na+/H+ exchange, calcium uptake as it relates to the molt cycle, heavy metal sequestration and detoxification, and anion movements into and across epithelial cells. In addition to defining the properties and mechanisms of cation movements across specific cell borders, work over the past 5 yr has also centered on defining the molecular nature of certain transport proteins such as the Na+/H+ exchanger in gill and gut tissues. Monovalent anion transport proteins of the gills and gut have received attention as they relate to osmotic and ionic balance in euryhaline species. Divalent anion secretion events of the gut have been defined relative to potential roles they may have in hyporegulation of the blood and in hepatopancreatic detoxification events involving complexation with cationic metals.
Albert, J., Lingle, C. J., Marder, E., and O'Neil, M. B. (1986). A GABA-activated chloride-conductance not blocked by picrotoxin on spiny lobster neuromuscular preparations. Br J Pharmacol 87, 771-9.
Conductance increases to gamma-aminobutyric acid (GABA) were recorded in the gm6b and opener muscle of the spiny lobsters, Panulirus interruptus and P. argus. GABA-evoked responses were insensitive to picrotoxin at concentrations as high as 5 X 10(-5) M. Some blockade by picrotoxin was observed at higher concentrations. In normal physiological saline, the reversal potential of the Panulirus GABA- induced response was near the resting potential. The reversal potential was unaffected by reductions in sodium and calcium. Reduction of chloride by 50% resulted in a greater than 10 mV shift in the reversal potential of the GABA-induced response. Muscimol was able to mimic the action of GABA while baclofen was without effect. Bicuculline was a weak blocker. Avermectin B1a irreversibly increased the chloride permeability of the gm6b membrane. This conductance increase was blocked by picrotoxin over a range of concentrations similar to those required for blockade of the GABA-induced response. GABA-induced responses of the gm6b muscle of Homarus americanus were blocked almost completely by picrotoxin 10(-6) M. Sensitivity to picrotoxin is not invariably associated with GABA-activated chloride-mediated conductance increases. It is suggested that alteration in the binding-site for picrotoxin on the GABA-activated chloride-ion channel does not change other functional characteristics of the GABA-induced response.
Alvarado-Alvarez, R., Becerra, E., and Garcia, U. (1999). A high-resolution in vitro bioassay to identify neurons containing red pigment concentrating hormone. Journal of Experimental Biology 202, 1777-1784.
The release of red pigment concentrating hormone (RPCH) by single peptidergic neurons of the crayfish X organ/sinus gland system (XO-SG) was demonstrated using a novel in vitro bioassay in which XO neurons were cocultured with tegumentary erythrophores. Local retraction of the pigmentary matrix within filipodia from erythrophores plated next to presumptive RPCH- containing neurons suggest spontaneous hormone release. Topical application of synthetic RPCH onto long filipodia also produced a local response. The time course of pigmentary matrix aggregation depended on the dose of synthetic RPCH. The effect of peptide on the cultured target cells was blocked by a polyclonal antiserum against RPCH. In co-culture conditions, the time course of pigmentary matrix aggregation was accelerated when presumptive RPCH-containing neurons were depolarized by intracellular current injection or by voltage- clamping to activate the Ca2+ current. The aggregation response evoked by these maneuvers was similar to that obtained with synthetic RPCH at a concentration of 1 fmol l(-1). The immune serum was also used to identify a subset of 3-7 immunoreactive neurons localized in the external rim of the XO close to the medulla interna. Under culture conditions, this subset of neurons corresponded to the cells that induced the erythrophore response.
Andersen, S. O. (1998). Characterization of proteins from arthrodial membranes of the lobster, Homarus americanus. Comparative Biochemistry and Physiology a-Molecular and Integrative Physiology 121, 375-383.
A total of six proteins from the abdominal arthrodial membrane (intersegmental membrane) of the lobster, Homarus americanus, were purified and their amino acid sequences were determined by a combination of mass spectrometry and Edman degradation. The proteins are acidic with pI-values close to 4 and they all have molecular masses approximate to 12 kDa. The sequences of five of the proteins differ in only a few residues, while the sixth protein differs from the others in more than half of the positions. Only little similarity is observed between the sequences of the arthrodial membrane proteins and those of proteins purified from the calcified parts of the exoskeleton of H. americanus. The arthrodial membrane proteins contain the Rebers-Riddiford consensus sequence common in proteins from insect cuticles. Comparison of the complete sequences to the sequences available in databases shows that the lobster membrane proteins are more closely related to proteins from insect pliant cuticles than to proteins derived from cuticles destined for sclerotization. Characteristic features in the protein sequences are discussed, and it is suggested that the various sequence regions have specific roles in determining the mechanical properties of arthrodial membranes. (C) 1998 Elsevier Science Inc. All rights reserved.
Andersen, S. O. (1999). Exoskeletal proteins from the crab, Cancer pagurus. Comparative Biochemistry and Physiology a-Molecular and Integrative Physiology 123, 203-211.
Twelve proteins from calcified regions and five from flexible regions (arthrodial membranes) of the exoskeleton of Cancer pagurus have been purified and sequenced. One of the proteins from calcified exoskeleton is identical to one of the arthrodial membrane proteins. Several of the proteins from the calcified regions resemble proteins from corresponding regions of the exoskeleton of the lobster, Homarus americanus, in containing either two or four copies of an 18-residue sequence motif, which so far has been found only in crustacean calcified exoskeletons. The proteins obtained from the flexible arthrodial membranes resemble the proteins from lobster arthrodial membranes, and the similarities are shared with a number of proteins from flexible cuticles in insects, indicating that the common features in these proteins may be important for the mechanical properties of the materials in which they occur. (C) 1999 Elsevier Science Inc. All rights reserved.
Anderson, M., and Cooke, I. M. (1969). Neuromusclar transmission in the heart of the lobster Homarus americanus. Experientia Suppl 15, 166-8.
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Anderson, M., and Cooke, I. M. (1971). Neural activation of the heart of the lobster Homarus americanus. J Exp Biol 55, 449-68.
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Anger, K. (1998). Patterns of growth and chemical composition in decapod crustacean larvae. Invertebrate Reproduction & Development 33, 159-176.
In meroplanktonic larvae, growth is accompanied by developmental changes in physiological, biochemical, morphological, behavioural, and ecological traits, and these patterns are further modified by variations in the physico- chemical environment. This paper reviews patterns of growth and chemical composition in planktotrophic marine decapod larvae developing under constant close to optimal conditions, as well as some alterations imposed on these patterns by nutritional, thermal, osmotic, or other stress. Different suboptimal conditions such as food limitation, unsuitable temperatures, or low salinity stress may exert similar bioenergetic effects which, in general, can be measured as a decline in the rates of development and growth or in changing proportions of chemical constituents of larval biomass. The fractions of carbon (C), total lipids, triacylglycerides (TAG), polyunsaturated fatty acids (PUFA), RNA, and ratios of carbon:nitrogen (C:N), lipid:protein, TAG:total polar lipid, and RNA:DNA have been used as chemical indicators of physiological condition. Quantitative relationships between elemental(C, N) and proximate biochemical fractions (lipid, protein) may vary with nutritional condition, developmental mode (planktotrophy vs. lecithotrophy), clade, and possibly, between field-caught and laboratory-reared larvae ("domestication effects"). Besides further comparative laboratory investigations, more field data are necessary to increase the realism of our models of larval growth and development in the Decapoda and other crustaceans.
Anosike, E. O., Moreland, B. H., and Watts, d. (1975). Evolutionary variation between a monomer and a dimer arginine kinase. Purification of the enzyme from Holothuria forskali and a comparison of some properties with that from Homarus vulgaris. Biochem J 145, 535-43.
1. A purification procedure for the dimeric arginine kinase of the sea cucumber Holothuria forskali is described. 2. The enzyme has a mean molecular weight of 77250 and is composed of two equal, dissociable subunits. 3. It also shows co-operativity between substrate binding at one catalytic site to a much greater extent than the nomomeric lobster arginine kinase for which such co-operativity could not be detected unambiguously. The constants for substrate binding are reported assuming that the enzyme follows rapid-equilibrium random kinetics. From a comparison with other species, the development of co-operativity between the nucleotide- and guanidine-binding sites on one subunit is suggested to have occurred more than once in the evolution of the phosphagen kinases and is not dependent on subunit aggregation. 4. Both enzymes show similar pH profiles for thermal inactivation at 22 degrees C and have very similar stabilities. Above 40 degrees C the dimeric enzyme is much more stable than the monomer. Rate constants for heat inactivation and Arrhenius activation energies are reported. 5. The dimeric enzyme is also more stable to urea inactivation. Substrates and argininic acid all improve the stability of both enzymes. The effects of individual substrates are more distincitive with the dimeric enzymes and increase its stability to an extent that makes it about as stable as dogfish creatine kinase. In the physiological range dimerization does not seem to confer any particular advantage with respect to stability over the monomer form.
Aono, H., Diaz, G. G., and Mori, K. (1994). Cytolysis of hemocytes induced by serum and plasma in three crustaceans, Panulirus japonicus, Penaeus japonicus, and Homarus americanus. Dev Comp Immunol 18, 265-75.
The effects of serum and/or plasma of three crustacean species on cellular morphology of homologous and heterologous hemocytes were observed using an in vitro short-term culture system. When hemocytes of the spiny lobster, Panulirus japonicus, isolated from hemolymph were mixed with serum of the same species, rapid cytolysis occurred in hyaline and semigranular cells. Plasma of Panulirus japonicus dialyzed against artificial sea water (dialyzed plasma) had the same cytolytic effect on hyaline and semigranular cells. Although the granular cells are not lysed, exposure to serum and plasma does produce changes in morphology and behavior (adhesion and spreading). Dialyzed plasma of the shrimp (Penaeus japonicus) and the lobster (Homarus americanus) also showed the same phenomena on homologous hemocytes. Dialyzed plasma of these three species had a less pronounced cytolytic effect on heterologous hemocytes. The cytolytic activity of the dialyzed plasma was weakened by heat treatment and inactivated by protease treatment. These results suggest that a protein factor(s) that specifically induces bursting of hyaline and semigranular cells exists in plasma of crustaceans.
Arbiser, Z. K., and Beltz, B. S. (1991). SCPB-and FMRFamide-like immunoreactivities in lobster neurons: colocalization of distinct peptides or colabeling of the same peptide(s)? J Comp Neurol 306, 417-24.
Virtually all of the SCPB-like immunoreactive neurons (ca. 60 cells) in the lobster Homarus americanus also contain FMRFamide-like immunoreactivity. Control experiments reveal that SCPB-and FMRFamide- like immunoreactivities are successfully preadsorbed with their specific antigens, while the normal staining pattern is retained following preadsorption of each antibody with the alternate peptide. These experiments potentially lead to the conclusion that the anti-SCPB and anti-FMRFamide antibodies are labeling distinct compounds that are colocalized in lobster neurons. The lobster nervous system does not, however, contain authentic FMRFamide, but rather several FMRFamide-like compounds (Trimmer et al., J. Comp. Neurol. 266:16-26, 1987). The most abundant of these is the octapeptide TNRNFLRFamide. Experiments demonstrate that SCPB-like immunoreactivity is completely preadsorbed with synthetic TNRNFLRFamide, while there is a significant or complete loss of staining after preadsorption of the FMRFamide antibody with this molecule. Met-enkephalin-Arg-Phe-amide (YGGFMRFamide), an extended opioid peptide containing the FMRFamide sequence, also preadsorbs SCPB- and FMRFamide-like immunoreactivities, while Met-enkephalin-Arg-Phe (YGGFMRF) has no effect on the staining properties of these antibodies. These results suggest that the SCPB antibody can bind to extended forms of FMRFamide-like molecules, and that anti-SCPB and anti-FMRFamide antibodies may be colabeling one or more FMRFamide-like molecules in lobster neurons.
Asher, I. M. (1972). Effects of DMSO on the electrical response of Homarus nerves frozen to - 20 degrees C, -30 degrees C and at room temperature. Cryobiology 9, 153-62.
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Ashton, F. T., Beinbrech, G., and Pepe, F. A. (1987). Subfilament organization in myosin filaments of the fast abdominal muscles of the lobster, Homarus americanus. Tissue Cell 19, 51-63.
The myosin filaments of the fast abdominal muscle of the lobster are about 2.7 microns long with a diameter of about 20 nm. They have a low density core in transverse sections except for a short portion in the middle of the filaments about 140 nm in length which is solid. In the solid region the diameter of the filaments is 25 nm. The wall of the filaments is made up of 12 subfilaments arranged in six pairs in a single layer around the wall. The spacing between the subfilaments of a pair is 3.4 nm and the spacing between successive pairs is 8.4 nm. An extra density is present on the inner surface of the wall of the filament along the entire length of the tubular portion of the filament. This density is always adherent to the wall and in serial transverse sections of the same filament its position changes from section to section without any apparent pattern to the change. No structural organization could be detected in this extra density.
Atema, J. (1998). Tracking turbulence: Processing the bimodal signals that define an odor plume. Biological Bulletin 195, 179-180.
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Audsley, N., McIntosh, C., and Phillips, J. E. (1992). Isolation of a neuropeptide from locust corpus cardiacum which influences ileal transport. J Exp Biol 173, 261-74.
1. Schistocerca gregaria ion-transport peptide (Scg-ITP) was isolated from aqueous extracts of the corpus cardiacum by a four-step procedure, utilizing reverse-phase high-performance liquid chromatography for separation and stimulation of a Cl(-)-dependent short-circuit current (Isc) across locust ilea as the bioassay. 2. Scg-ITP has an unblocked N terminus and an apparent relative molecular mass of 7700. Thirty-one residues (of an estimated 65) were identified by sequence analysis. 3. Scg-ITP is structurally related to a crustacean family of neuropeptides which includes the crustacean hyperglycaemic hormones from the shore crab Carcinus maenas and the crayfish Orconectes limosus and moult- inhibiting hormone and vitellogenesis-inhibiting hormone from the lobster Homarus americanus. 4. Scg-ITP has no sequence homology with neuroparsins (Nps). Nps are the only other neuropeptides isolated to date that might regulate reabsorption in an insect hindgut (rectum).
Balon, L. M., and Ahearn, G. A. (1991). Both Na+ and Cl- gradients energize NaCl/L-glutamate cotransport in lobster hepatopancreatic brush border membrane vesicles. Biochim Biophys Acta 1067, 123-30.
Previous work with L-[3H]glutamate transport by lobster (Homarus americanus) hepatopancreatic brush border membrane vesicles (BBMV) indicated that the transport of this amino acid was stimulated by the presence of both Na+ and Cl- ions in the external medium, however, the specific catalytic or energetic role of each monovalent ion in amino acid transfer was not established (Ahearn and Clay (1987) J. Exp. Biol. 130, 175-191). The present study employs a variety of experimental treatments with this membrane preparation to clarify the nature of the ion dependency in the cotransport process. A zero-trans time course experiment using inwardly-directed transmembrane Na+ or Cl- gradients led to similar transient accumulations of the amino acid above equilibrium values in the presence of equilibrated concentrations of the respective counterions. The uptake overshoots observed in the presence of single ion gradients were significantly increased when gradients of both Na+ and Cl- were used simultaneously. When vesicles were pre-equilibrated with L-[3H]glutamate and either of the monovalent ions, an inwardly-directed gradient of each counterion led to the transient accumulation of additional labelled amino acid above its equilibrium concentration, indicating that either ion gradient was capable of energizing the net flow of L-glutamate. A cotransport stoichiometry of 1 Na+/1 Cl-/1 L-glutamate was established using the Static Head analysis where a balance of ion and amino acid driving forces were attained with a 7:1 Na+ or Cl- gradient (o greater than i) against a 7:1 L-glutamate gradient (i greater than o).
Bannister, R. C. A., and Addison, J. T. (1998). Enhancing lobster stocks: A review of recent European methods, results, and future prospects. Bulletin of Marine Science 62, 369-387.
This paper reviews the status of stock-enhancement studies on the clawed lobster, particularly recent experiments on Homarus gammarus in European waters. Previous attempts from the 1850s onwards with both H. gammarus and H. americanus showed little success, but since 1980, lobsters reared in the hatchery to juvenile stage XII have been released in substantial numbers at a range of sites in the United Kingdom, France, Norway, and Ireland. Releases on the order of thousands have yielded recaptures on the order of hundreds. This new success arises because juveniles were microwire tagged, released directly by divers onto known lobster habitat, and subsequently recaptured by dedicated field sampling and monitoring of commercial lobster landings. Hatchery lobsters showed little dispersal, they required 4 to 5 yrs to reach legal size, and some ovigerous females were recaptured. Field sampling tentatively suggests survival to legal size as high as 50%, but the overall recapture rate in the fishery was below 5%. Recaptures seem marginally higher in areas of low lobster density, but the experiments were not designed to answer ecological questions, and they cannot be used, to make substantive predictions about how stocking density and the local abundance of natural stock will affect survival and recapture rate. Before the biological and economic benefits of enhancement programs can be assessed, experimental testing is needed of whether hatchery-reared juveniles supplement or replace naturally settled lobsters. At current levels of recruitment, enhancement programs seem unlikely to be worthwhile, particularly compared with the implementation of restrictive management measures, but enhancement programs can be justified where there is some clear evidence of recruitment failure, as in Norway. At present lobster prices, the current recapture rate is well below that required to cover the present cost of constructing and running a moderate-sized hatchery from scratch. This economic appraisal is discouraging from a "put-and-take" ranching perspective, but a program aimed at enhancing breeding stock and independently financed from associated tourism or sea-life-center activity is still potentially viable.
Barbato, J. C., and Daniel, P. C. (1997). Chemosensory activation of an antennular grooming behavior in the spiny lobster, Panulirus argus, is tuned narrowly to L- glutamate. Biological Bulletin 193, 107-115.
Antennular grooming behavior (AGB) is a stereotyped behavior in crustaceans in which the first pair of antennae, the major olfactory organs, are clasped and wiped repetitively by the third maxillipeds, which also serve as feeding appendages. AGB apparently functions to clear away accumulating debris on or between the antennular aesthetascs (olfactory sensilla). The purpose of this research was to determine whether AGB can be activated by chemicals commonly found in food odors. Lobsters were presented, via headset or handheld pipette, with 27 chemicals found in their food. One chemical, L-glutamate, evoked very high frequencies of wiping. Most chemicals tested were not stimulatory and only a few were weakly stimulatory (adenosine-5'-monophosphate, glycine, D-glutamate). This is surprising because previous studies have shown that other behaviors (antennular flick, search) can be evoked by a much broader array of chemicals found in food odorants. On the basis of these results, we propose that chemosensory neurons that specifically detect L-Glu activate AGB through a recently described non-olfactory pathway. Furthermore, we propose that the role of L-Glu in evoking AGB is based on its electrostatic properties. Because it has a high probability of electrostatic adherence to the antennular cuticle, L-Glu is a sensitive indicator of fouling by food-associated chemicals and thus an appropriate compound to stimulate antennular grooming.
Barki, A., and Karplus, I. (1999). Mating behavior and a behavioral assay for female receptivity in the red-claw crayfish Cherax quadricarinatus. Journal of Crustacean Biology 19, 493-497.
Females of the red-claw crayfish Cherax quadricarinatus do not undergo external changes that may indicate receptivity. To study mating behavior and develop a behavioral assay for female receptivity, pairs of size-matched males and females were housed in aquaria each divided in two by a transparent partition, with a tube-shelter on each side. Observations on shelter occupation were conducted daily at 30-min intervals. In addition, each pair was allowed to interact daily for 10 min after lifting the partition. The female almost invariably initiated the mating activity. Though infrequently observed prior to copulation in this study, the male performed a stereotyped courtship action, namely, sudden thrusts of his chelipeds toward the female. Unlike most crayfishes, the male did not use the claws to grasp, position, or hold the female during copulation, and positioned himself on his dorsum underneath the female. The percentage of observations in which the female was outside the shelter was much higher on the day of mating than on any other day prior to, or following, mating. No behavioral clues for female receptivity were detectable during the daily en counters prior to the day of mating. The level of shelter occupation by females reliably indicates receptivity; it is limited, however, to the day of mating.
Barron, M. G., Gedutis, C., and James, M. O. (1988). Pharmacokinetics of sulphadimethoxine in the lobster, Homarus americanus, following intrapericardial administration. Xenobiotica 18, 269-76.
1. The pharmacokinetics and tissue distribution of intrapericardially administered sulphadimethoxine were studied in the lobster Homarus americanus. 2. Pharmacokinetic analysis of haemolymph concentration- time data indicated that a two compartment model best described sulphadimethoxine disposition, and that there were no apparent sex differences in the lobster. Analysis of total body clearance (Clb), apparent steady-state volume of distribution (Vss), area under the curve, and plasma protein binding in lobsters receiving 21, 42 and 55 mg/kg sodium sulphadimethoxine indicated that the pharmacokinetics were independent of dose. 3. Mean parameter estimates for Clb, Vss, and terminal half life were 13.8 ml/h/kg, 1369 ml/kg, and 76.7 h, respectively. Binding of sulphadimethoxine to haemolymph proteins was linear, with a mean of 53.5% bound. 4. Analysis of the tissue distribution of radiolabelled sulphadimethoxine at 4, 48 and 336 hours after a 42 mg/kg dose indicated that sulphadimethoxine was excreted slowly by the lobster, with the muscle, shell and haemolymph holding the largest fraction of the dose at early times. After 2 weeks, 9.5% of the radiolabel remained in the animal, with the hepatopancreas and digestive tract holding the greatest concentration of the dose.
Barron, M. G., and James, M. O. (1994). Oral bioavailability and disposition of sulphadimethoxine in lobster, Homarus americanus, following single and multiple dosing regimens. Xenobiotica 24, 921-31.
1. Single and multiple oral doses of sulphadimethoxine or sodium sulphadimethoxine were administered by gavage to lobster, and sequential samples of haemolymph were taken for analysis of parent sulphadimethoxine. Single doses of sodium sulphadimethoxine were given over a dose range of 14-70 mg/kg. Five 42-mg/kg doses of sulphadimethoxine on alternate days were administered for the multiple- dose studies. Some experiments were conducted with radiolabelled (35S or 14C) sulphadimethoxine, and the tissue distribution of radioactivity was determined at different killing times. 2. Pharmacokinetic parameters were obtained by fitting sulphadimethoxine concentrations in haemolymph to a one-compartment model. Oral bioavailability at the 42- mg/kg dose, calculated from the area under the haemolymph concentration- time curve (AUC) relative to the AUC from intravascular administration, was between 47 and 52% for single or multiple doses of the free drug. The bioavailability of sodium sulphadimethoxine was dose dependent, at 97% for the 14 mg/kg dose, and 25% for the 70-mg/kg dose. The low bioavailability at the high dose probably resulted from poor absorption due to the limited solubility of sulphadimethoxine at the low pH of the lobster gastrointestinal tract. 3. Sulphadimethoxine and several polar metabolites were excreted in lobster urine. Polar metabolites were also found in the hepatopancreas and haemolymph. At least 20% of the 42- mg/kg dose was metabolized. The major vertebrate metabolite of sulphadimethoxine, N-acetylsulphadimethoxine, was a very minor metabolite in lobster. The identities of the polar metabolites were not established. 4. Elimination of sulphadimethoxine residues from muscle to 0.1 microgram sulphadimethoxine equivalent/g tissue required 40 days after a single dose, or 44 days after the last of multiple doses. Concentrations of sulphadimethoxine residues in all other tissues were always greater than muscle concentrations. Data showed that sulphadimethoxine residues were very persistent in lobster tissues.
Barshaw, D. E., and Rich, D. R. (1997). An analysis of substrate selection by postlarval American lobsters, Homarus americanus, using a dynamic optimization model. Oikos 80, 554-564.
During the fourth stage of larval development the American lobster (Homarus americanus) leaves the plankton and becomes benthic. Before final settlement lobsters sample different substrates which may be accepted or rejected. Upon rejection the lobster returns to the plankton before sampling another substrate. In this paper we present a model of the substrate selection behavior of settling lobsters using dynamic optimization techniques. The model examines the role of substrate quality and availability, postlarval testing of substrates, and mortality associated with testing substrates, upon the decision to accept or reject the substrates sampled and predicts the eventual importance of each substrate in the recruitment of lobsters to reproductive age. Finally we apply the model using recent data on long-term survival of lobsters in the field. The model predicts that the high quality substrate (cobble) accounts for most of the adult lobster population, in spite of the much greater abundance of other, more marginal, substrates.
Barthe, J. Y., Mons, N., Cattaert, D., Geffard, M., and Clarac, F. (1989). Dopamine and motor activity in the lobster Homarus gammarus. Brain Res 497, 368-73.
Motor activity similar to agonistic behaviour is obtained after dopamine (DA) injection in lobster. Specially vigorous swimmeret beatings are observed and can be compared to the 'in vitro' motor activity elicited by DA superfusion of the isolated abdominal nervous system. DA-immunoreactive neurons stained by monoclonal antibodies in abdominal ganglia may be involved in swimmeret activation during the agonistic behavior.
Bayer, T. A., McClintock, T. S., Grunert, U., and Ache, B. W. (1989). Histamine-induced modulation of olfactory receptor neurones in two species of lobster, Panulirus argus and Homarus americanus. J Exp Biol 145, 133-46.
In two species of lobster, application of the biogenic amine, histamine (HA), to the soma of olfactory receptor cells suppressed both spontaneous and odour-evoked activity, as shown by electrophysiological recording from single cells. The action of HA was graded, reversible, specific to HA, and had a threshold between 0.1 and 1 mumol l-1. HA increased the conductance of the membrane, primarily to chloride ions. The vertebrate HA receptor antagonist, cimetidine, and the nicotinic receptor antagonist, d-tubocurarine, but not other known vertebrate HA receptor antagonists, reversibly blocked the action of HA. These results suggest that a histaminergic mechanism modulates stimulus- response coupling in lobster olfactory receptor cells and potentially implicate a novel HA receptor, pharmacologically similar to the one recently described in the visual system of flies.
Bayer, R., Riley, J., and Donahue, D. (1998). The effect of dissolved oxygen level on the weight gain and shell hardness of new-shell American lobster Homarus americanus. Journal of the World Aquaculture Society 29, 491-493.
New-shell American lobsters Homarus americanus stored in tidal pounds or on-shore tank systems are fed to promote weight gain and shell hardness prior to shipping. Maintaining adequate dissolved oxygen (DO) levels in the water is an important consideration in this process, and information on optimum DO levels is needed. In this study, 90 post-molt lobsters were weighed and tagged and held in a recirculating seawater system. Three DO treatments, 50%, 100%, and 250% saturation, were applied in three replicates; the lobsters were held for 35 d and fed daily. After this period they were re-weighed and shell hardness was measured. Results showed that increasing oxygen saturation above 100% did not increase weight gain or shell hardness and at lower levels (50%) there is only a trend to reduced shell hardness and weight gain.
Beglane, P. F., Grasso, F. W., Basil, J. A., and Atema, J. (1997). Far field chemo-orientation in the American lobster, Homarus americanus: Effect of unilateral ablation and lesioning of the lateral antennule. Biological Bulletin 193, 214-215.
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Behnke, R. D., Busquets-Turner, L., and Ahearn, G. A. (1998). Epithelial glucose transport by lobster antennal gland. Journal of Experimental Biology 201, 3385-3393.
Transport of D-[H-3]glucose into lobster (Homarus americanus) brush-border membrane vesicles (BBMVs) prepared by Mg2+ precipitation from antennal gland labyrinth-coelomosac tissue was examined. Influx of D-glucose occurred primarily by a phlorizin-sensitive, Na+-dependent carrier similar to that found in vertebrate renal epithelium. An inwardly directed Na+ gradient drove concentrative D-glucose uptake, whereas similar gradients of Li+ and K+ did not. Stimulation by the Na+ gradient was further enhanced by the imposition of an inside- negative potential difference and also by increases in the pH of the vesicle and incubation media. An analysis of cis inhibition of D-glucose uptake by a number of sugars and sugar derivatives indicated that the transporter requires (a) that the sugar substrate he a D-pyranose in the C1 chair conformation and (b) that the hydroxyl groups at C2 and C3 of the ring be unmodified and equatorial. Apparent kinetic parameters for glucose uptake were determined under zero-trans, short-circuited conditions. Maximal influx of D-glucose into vesicles was estimated to be 96 pmol mg(-1) protein s(-1) Half- maximal influx was determined to occur at 0.20mmoll(-1) D- glucose. The relationship between external Na+ concentration and glucose influx was sigmoidal, and the stoichiometry of Na+- dependent glucose transport found to be 3 Na+:1 glucose using the static head method.
Beltz, B., Eisen, J. S., Flamm, R., Harris-Warrick, R. M., Hooper, S. L., and Marder, E. (1984). Serotonergic innervation and modulation of the stomatogastric ganglion of three decapod crustaceans (Panulirus interruptus, Homarus americanus and Cancer irroratus). J Exp Biol 109, 35-54.
The serotonergic innervation of the stomatogastric ganglion (STG) of three decapod crustacean species, Panulirus interruptus, Homarus americanus and Cancer irroratus, was studied. Immunohistochemical techniques were used to study the distribution of serotonin-like staining in regions of the stomatogastric system in the three species. In C. irroratus and H. americanus, but not in P. interruptus, serotonin- like staining was found in fibres in the stomatogastric nerve and in neuropil regions of the STG. High performance liquid chromatography confirmed the presence of serotonin in STG of C. irroratus and H. americanus, but serotonin was not found in STG of P. interruptus. Electrophysiological experiments showed that the pyloric motor output of the STG of all three species was influenced by bath applications of serotonin. The STG of P. interruptus responded to serotonin concentrations as low as 10-9M; however the STG of the other two species did not respond until serotonin concentrations in excess of 10- 6M were applied. We conclude that serotonin may play a hormonal role in the control of the STG of P. interruptus, but is likely to be a neurotransmitter released by inputs to the STG of H. americanus and C. irroratus.
Beltz, B. S. (1999). Distribution and functional anatomy of amine-containing neurons in decapod crustaceans. Microscopy Research and Technique 44, 105-120.
One of the lessons learned from studying the nervous systems of phylogenetically distant species is that many features are conserved. Indeed, aminergic neurons in invertebrate and vertebrate systems share a multitude of common characteristics. In this review, the varied roles of serotonin, octopamine, dopamine, and histamine in decapod crustaceans are considered, and the distributions of the amine-containing cells are described. The anatomy of these systems reinforces the idea that amine neurons are involved in widespread modulation and coordination within the nervous system. Many aminergic neurons have long projections, linking multiple regions with a common input, and therefore are anatomically perfected as "gain setters." The developmental patterns of appearance of each amine in the crustacean nervous system are described and compared. The developmental picture suggests that transmitter acquisition is distinctive for each amine, and that the pace of acquisition may be co-regulated with target maturation. The distinctive roles that transmitters play during specific developmental periods may, ultimately, provide important clues to their functional contributions in the mature organism. Microsc. Res. Tech. 44:105-120, 1999. (C) 1999 Wiley-Liss, Inc.
Bend, J. R., Hart, L. G., Guarino, A. M., Rall, D. P., and Fouts, J. R. (1976). Distribution and excretion of (14C)-2,4,5,2',5'-pentachlorobiphenyl in the lobster (Homarus americanus) and the dogfish shark (Squalus acanthias). pp. 292-301. In: Buckley JL, et al., ed. National Conference on Polychlorinated Biphenyls. Washington, Environmental Protection Agency, .
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Benton, J., Huber, R., Ruchhoeft, M., Helluy, S., and Beltz, B. (1997). Serotonin depletion by 5,7-dihydroxytryptamine alters deutocerebral development in the lobster, Homarus americanus. Journal of Neurobiology 33, 357-373.
The olfactory and accessory lobes constitute prominent histological structures within the larval and mature lobster deutocerebrum, and both are associated with a dense innervation from paired serotonergic nerve cells, the dorsal giant neurons (DGNs), During development, the cell bodies of the DGNs are the first central somata to express serotonin (5-HT), and the onset of their 5-HT immunoreactivity coincides with the beginning of accessory lobe formation, In contrast, the olfactory lobe anlagen emerge much earlier and grow in the apparent absence of serotonin, The role of serotonergic input for the development of these brain structures was investigated in lobster embryos after serotonin had been depleted pharmacologically with the neurotoxin 5,7-dihydroxytryptamine. A similar to 90% reduction of serotonin was confirmed in eggs using high-performance liquid chromatography with electrochemical detection. Morphometric analyses suggested that serotonin depletion dramatically slowed the growth of olfactory and accessory lobes, although glomeruli differentiated at the normal time in both areas. The toxin exhibited a high degree of specificity for serotonergic neurons and associated target regions, and serotonin depletion persisted for at least 2 months following treatment. The goal of future experiments is to determine which of the cell types that innervate the olfactory and accessory lobes are affected by toxin treatment, thereby resulting in the retarded growth of these areas. (C) 1997 John Wiley & Sons, Inc.
Benyamin, Y., Robin, Y., and Regnouf, F. (1977). [Antigenic activity of lobster (Homarus vulgaris) arginine kinase and its cyanogen bromide fragments]. C R Acad Sci Hebd Seances Acad Sci D 284, 1955-8.
The antigenic saturation of lobster arginine kinase (38 000 daltons) by its specific antibodies has been studied. It was found that seven antigenic binding sites are simultaneously reactive on the surface of the enzyme in the presence of a large excess of antibodies or of their Fab fragments. After cyanogen bromide cleavage, the antigenic reactivity is distributed on several fragments of various sizes.
Berkey, C., and Atema, J. (1999). Individual recognition and memory in Homarus americanus male- female interactions. Biological Bulletin 197, 253-254.
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Berlind, A. (1998). Dopamine and 5-hydroxytryptamine actions on the cardiac ganglion of the lobster Homarus americanus. Journal of Comparative Physiology a-Sensory Neural and Behavioral Physiology 182, 363-376.
The cardioexcitor monoamines dopamine (DA) and 5- hydroxytryptamine (5HT) accelerate bursting by isolated cardiac ganglia of the lobster Homarus americanus most effectively when they act on a region of the ganglionic trunk anterior to the small cells which have been considered the pacemakers of the system. 5HT may exert its acceleratory action by depolarizing cell processes. Neither the somata nor the spike-initiating zones of the small cells have to be directly exposed to 5HT or DA in order for acceleration to occur. When 5HT is applied selectively to the small cells bursts are prolonged, probably as a result of increases in the duration of the endogenous burst-organizing potentials (driver potentials) generated by these neurons. This action on the small cells can lead to prolonged and intensified bursts of the full ganglion during the onset of 5HT action when the whole ganglion is exposed to the monoamine. Neither DA nor 5HT has a direct effect on the characteristics of large cell (motorneuron) driver potentials.
Bertrand, R., Barman, T. E., and Travers, F. (1979). Substrate binding sites on arginine phosphokinase (Homarus vulgaris). Biochimie 61, 705-9.
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Beyette, J. R., and Mykles, D. L. (1992). Immunocytochemical localization of the multicatalytic proteinase (proteasome) in crustacean striated muscles. Muscle Nerve 15, 1023-35.
Multicatalytic proteinase (MCP) is thought to play a central role in the processing and turnover of intracellular proteins in eukaryotic cells. Immunocytochemistry was used to determine the intracellular distribution of the MCP in the claw muscles of the land crab, Gecarcinus lateralis, and the claw and abdominal muscles of the American lobster, Homarus americanus. Cryosections were stained with an affinity-purified polyclonal antibody to lobster MCP that cross-reacted with the land crab enzyme. Two types of staining were observed: a diffuse cytoplasmic staining, and a dense aggregate staining primarily associated with invaginations of the cell membrane. The cytoplasmic staining appeared reticulated in favorable transverse sections due to a preferential localization of MCP to the intermyofibrillar space. The aggregate staining was associated with neither nuclei nor mitochondria, since stains specific for these organelles (Hoechst stain and nicotinamide adenine dinucleotide diaphorase histochemistry, respectively) did not colocalize with the aggregates. Trypsinlike peptidase activities of isolated microsomal and postmicrosomal fractions indicated that less than 1% of the total MCP was associated with the microsomal fraction. Immunoprecipitation of the same fractions confirmed the presence of MCP in the microsomes as well as in the cytosol. These results suggest that the MCP is primarily associated with cytoplasmic components; the aggregate staining may result from the association of the MCP with cellular membrane systems.
Bijlholt, M., and van Bruggen, E. F. (1986). A model for the architecture of the hemocyanin from the arthropod Squilla mantis (Crustacea, Stomatopoda). Eur J Biochem 155, 339-44.
Squilla mantis hemocyanin is composed of two hexameric subunits but has electron microscopic profiles different from other bis-hexameric hemocyanins, e.g. Astacus and Homarus. We distinguished three different electron microscopic profiles of S. mantis hemocyanin: two sideviews and a topview. These profiles were studied using computer image alignment and correspondence analysis [Van Heel, M. and Frank, J. (1981) Ultramicroscopy 6, 187 - 194]. With the results of this analysis we were able to build a three-dimensional model for the quaternary structure of this hemocyanin. In this model the two hexamers are stacked in such a way that their hexagonal surfaces overlap to about 60% of their width. In the overlap area four subunits are arranged in two different interhexameric pairs, each forming a bridging area between the two hexamers.
Blitz, D. M., Christie, A. E., Coleman, M. J., Norris, B. J., Marder, E., and Nusbaum, M. P. (1999). Different proctolin neurons elicit distinct motor patterns from a multifunctional neuronal network. Journal of Neuroscience 19, 5449-5463.
Distinct motor patterns are selected from a multifunctional neuronal network by activation of different modulatory projection neurons. Subsets of these projection neurons can contain the same neuromodulator(s), yet little is known about the relative influence of such neurons on network activity. We have addressed this issue in the stomatogastric nervous system of the crab Cancer borealis. Within this system, there is a neuronal network in the stomatogastric ganglion (STG) that produces many versions of the pyloric and gastric mill rhythms. These different rhythms result from activation of different projection neurons that innervate the STG from neighboring ganglia and modulate STG network activity. Three pairs of these projection neurons contain the neuropeptide proctolin. These include the previously identified modulatory proctolin neuron and modulatory commissural neuron 1 (MCN1) and the newly identified modulatory commissural neuron 7 (MCN7). We document here that each of these neurons contains a unique complement of cotransmitters and that each of these neurons elicits a distinct version of the pyloric motor pattern. Moreover, only one of them (MCN1) also elicits a gastric mill rhythm. The MCN7-elicited pyloric rhythm includes a pivotal switch by one STG network neuron from playing a minor to a major role in motor pattern generation. Therefore, modulatory neurons that share a peptide transmitter can elicit distinct motor patterns from a common target network.
Borroni, P. F., Handrich, L. S., and Atema, J. (1986). The role of narrowly tuned taste cell populations in lobster (Homarus americanus) feeding behavior. Behav Neurosci 100, 206-12.
A whole-animal behavioral assay was developed to measure responses to chemical stimulation of the walking leg (taste) receptors of lobsters. Lesions of only the taste receptors abolished the dactyl clasping response, a result demonstrating that such receptors are necessary to elicit this response. Then the stimulatory effectiveness of natural and synthetic mixtures was determined, particularly of 6 single compounds (glutamate, glutamine, NH4Cl, betaine, aspartate, and taurine) for which the legs have prominent, narrowly tuned receptor cell populations. The results showed that a synthetic mixture of the 22 principal amino acids and amines present in mussel tissue is as powerful a stimulus as either a homogenate of such tissue or its purified extract. Of the single compounds, only NH4Cl was stimulatory at the behavioral level; glutamate was not despite the fact that glutamate receptors are the predominant cell population known in lobster legs. Even a mixture of the 6 single compounds in their natural mixture ratio was not very stimulatory (it was even less stimulatory than the sum of the responses to each single compound), a result suggesting the occurrence of suppressive interactions. The complementary mixture, that is, the synthetic mixture without the 6 single compounds, was equally unstimulatory. It is unlikely that mixture suppression alone is responsible for the poor behavioral responses to single compounds such as glutamate, and to the partial mixtures that were tested. Full response to the more complex mixture of 22 compounds demonstrates that special mixture combinations can "override" mixture suppression. Such signal mixtures may represent the lobster leg's picture of food.
Borroni, P. F., and Atema, J. (1988). Adaptation in chemoreceptor cells. I. Self-adapting backgrounds determine threshold and cause parallel shift of response function. J Comp Physiol [A] 164, 67-74.
1. The self-adapting effects of chemical backgrounds on the response of primary chemoreceptor cells to superimposed stimuli were studied using lobster (Homarus americanus) NH4 receptor cells. 2. These receptors responded for several seconds to the onset of the backgrounds, and then returned to their initial level of spontaneous activity (usually zero). The strongest response always occurred only during the steepest concentration change; the response then decayed back to zero or to the earlier spontaneous firing level, while the background concentration was still rising, and remained silent during the entire time that the background was maintained constant (20-30 min) 3. Exposure to constant self-adapting backgrounds eliminated the response of NH4 receptor cells to stimuli of concentration lower than the background, and reduced the responses to all higher stimulus concentrations tested by a nearly equal amount. This resulted in a parallel shift of the stimulus- response function to the right along the abscissa. 4. Since the response threshold was completely re-set by adaptation to backgrounds, NH4 receptors seem to function mostly as detectors of relative rather than absolute stimulus intensity across their entire dynamic range: the response to a given stimulus-to-background ratio remained the same over 3 log step increases of background concentration. 5. As in other sensory modalities, a parallel shift of response functions appears to be an important property of chemoreceptor cells, allowing for this sensory system to function over a wider stimulus intensity range than the instantaneous dynamic range of individual receptor cells.
Bouligand, Y. (1999). Remarks on the geometry of micelles, bilayers and cell membranes. Liquid Crystals 26, 501-515.
Starting from simple geometric properties of parallel surfaces, it is suggested that bilayers, and also monolayers, present two spontaneous principal curvatures gamma and gamma', so that a narrow disc of freely deformable bilayer might adopt either a 'saddle' shape, or a 'hat' shape, or a cylindrical shape. Besides the usually considered spontaneous splay c(0) = gamma + gamma', there is also a spontaneous gaussian curvature g(0) = gamma gamma', with noticeable effects in strongly curved bilayers. An excess of area of the median hydrophobic level with respect to the mean area occupied by the two hydrophilic layers creates a saddle shape, whereas a deficit leads to a hat shape, the equality corresponding to a cylindrical shape. The usual two layers theory of the spontaneous curvature seems to be improved by considering the role of a median layer. We have tried to illustrate this new point of view by many examples. Due to their asymmetry, monolayers and cell membranes give rise to micelles and vesicles of comparable geometries, but of very different sizes. At the considered scales, a term of order higher than quadratic, such as k(t)(cc' - gamma gamma')(2), seems to be necessary in the expression of the elastic energy.
Bowser, P. R., Rosemark, R., and Reiner, C. R. (1981). A preliminary report of vibriosis in cultured American lobsters, Homarus americanus. J Invertebr Pathol 37, 80-5.
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Breithaupt, T., Lindstrom, D. P., and Atema, J. (1999). Urine release in freely moving catheterised lobsters (Homarus americanus) with reference to feeding and social activities. Journal of Experimental Biology 202, 837-844.
Previous studies suggest that urine-borne pheromones play an important role in lobster agonistic and sexual behaviour. This paper investigates the pattern of urine release in catheterised, but otherwise freely moving, adult lobsters with respect to feeding, social and non-social activities. Lobsters on average released 4.1 ml (1% of body mass) of urine over a 12 h period; this more than doubled to 10.6 ml over the 12 h period after feeding. Hourly monitoring revealed that most urine was released in the first hour after feeding (2.84 ml). With the exception of the first hours after feeding, urine release was intermittent, with pauses lasting up to 17 h. The probability of urine release per hour in unfed lobsters was 0.34 (median); this value increased during agonistic interactions elicited by the introduction of a conspecific (median 0.63) and during activity initiated by non-social disturbance (median 0.56). Mean urine volume during output hours in unfed lobsters amounted to 1.09 ml h(-1). This volume was significantly increased by the presence of a conspecific (1.88 ml h(-l)) and decreased during activity initiated by non- social disturbances (0.56 ml h(-1)). No sex-specific differences in urine release were found. The data demonstrate that lobsters control their urine release in a manner dependent on behavioural context. This supports recent findings suggesting the use of urine for chemical signalling in agonistic interactions.
Brevet, A., Zeitoun, Y., and Pradel, L. A. (1975). Comparative structural studies of the active site of ATP: guanidine phosphotransferases. The essential cysteine tryptic peptide of taurocyamine kinase from Arenicola marina. Biochim Biophys Acta 393, 1-9.
The active cysteinyl residues of dimeric taurocyamine kinase from Arenicola marina were labelled with N-ethyl-[1-14C]maleimide. The resulting inactivated N-ethyl-[1-14C]succinimido enzyme was then subjected to tryptic hydrolysis. The peptide containing the labelled essential cysteinyl residue was isolated. The amino acid sequence of this peptide is Leu-Gly-Tyr-Leu-Gly-Thr-[14C]-Cys-Pro-Thr-Asn-Ile-Gly- Leu-Arg. This sequence is very similar to that of homologous ATP:guanidine phosphotransferases previously studied, arginine kinase from Homarus vulgaris muscle, creatine kinase from ox brain and ox muscle, and from rabbit muscle, and lombricine kinase from Lubricus terrestris.
Briggs, R. P., Atkinson, R. J. A., McAliskey, M., and Rogerson, A. (1997). Histriobdella homari on Nephrops norvegicus from the Irish Sea and Clyde Sea area. Journal of the Marine Biological Association of the United Kingdom 77, 557-559.
Histriobdella homari is a polychaete annelid belonging to the Order Eunicida and Family Histriobdellidae. Histriobdella homari is normally found in the gill chambers or among the eggs of the lobster Homarus vulgaris from the English Channel (Roscoff) and in the southwestern part of the North Sea (George & Hartmann-Schroder, 1985). Two independent sightings of H. homari living on the pleopods of Nephrops norvegicus from the Irish Sea and Clyde Sea area are reported.
Britton, G., Weesie, R. J., Askin, D., Warburton, J. D., GallardoGuerrero, L., Jansen, F. J., deGroot, H. J. M., Lugtenburg, J., Cornard, J. P., and Merlin, J. C. (1997). Carotenoid blues: Structural studies on carotenoproteins. Pure and Applied Chemistry 69, 2075-2084.
alpha-Crustacyanin, the 320 kDa astaxanthin-protein from the carapace of the lobster, Homarus gammarus, is the best known of the blue-purple carotenoproteins found in marine invertebrate animals. Reconstituted alpha-crustacyanin complexes have been prepared from a range of natural and synthetic carotenoids. Only normal C-40 carotenoids in the all-E configuration fit into the binding site, though some variation in the ring size, shape and methylation pattern is tolerated. The C(20) and C(20') methyl groups must be present; presumably these are involved in essential steric interactions. The main structural requirement is the presence of keto groups at C(4) and C(4'); these must be conjugated with the main polyene chain. Circular dichroism shows that the carotenoid chromophore experiences a chiral twist, but this is not a major factor in the spectral shift, and that the two astaxanthin molecules in the beta- crustacyanin dimer are close together and show some interaction in the excited state. Resonance Raman and NMR spectroscopy of complexes containing C-13-labelled astaxanthins shows that the blue colour can be attributed to perturbation of the ground- state electronic structure of the carotenoid, caused by polarization of the chromophore. The results are consistent with protonation of the C(4) and C(4') keto groups, but the magnitude of the polarization effect is not the same in the two halves of the molecule.
Brouwer, M., Whaling, P., and Engel, D. W. (1986). Copper-metallothioneins in the American lobster, Homarus americanus: potential role as Cu(I) donors to apohemocyanin. Environ Health Perspect 65, 93-100.
The physiological function of copper(I)-metallothionein is not well understood. The respiratory function of hemocyanin, a copper(I)- containing respiratory protein found in the hemolymph of many invertebrates, has been known a long time. However, the mechanism by which Cu(I) is inserted into the oxygen-binding site of apohemocyanin is completely unknown. This investigation tests the hypothesis that copper(I)-metallothionein may act as a Cu(I) donor to apohemocyanin. To this end, copper-binding proteins and hemocyanin were purified from the digestive gland and hemolymph of the American lobster, Homarus americanus. In the presence of beta-mercaptoethanol, the copper-binding proteins can be resolved into three components on DEAE-cellulose. The first two have been characterized as metallothioneins, based on their high cysteine content and lack of aromatic amino acid residues. The cysteine content of the third component is half of that of components I and II. In the absence of beta-mercaptoethanol the three proteins elute as a single protein complex during ion-exchange chromatography. Components I and II show a strong tendency to polymerize, a process that is accompanied by the loss of protein-bound copper. The purified proteins are not capable of transferring Cu(I) to the active sites of completely copper-free apohemocyanin. They are capable, however, of transferring Cu(I) to active sites of hemocyanin containing reduced amounts of Cu(I), suggesting that the conformational state of hemocyanin is the determining factor in the Cu(I) transfer mechanism.
Brouwer, M., Winge, D. R., and Gray, W. R. (1989). Structural and functional diversity of copper-metallothioneins from the American lobster Homarus americanus. J Inorg Biochem 35, 289-303.
The role of copper metallothionein (CuMT) in copper metabolism and metalloenzyme activation is poorly understood. We have chosen marine crustaceans, in which a direct correlation exists between levels of Cu(I)MT and Cu(I)-hemocyanin during the molt cycle (Engel and Brouwer, Biol. Bull. 173, 239-251, 1987) as unique model systems to study the involvement of MTs in metalloprotein activation and degradation. We have isolated three low-molecular weight, cysteine-rich copper proteins from the American lobster Homarus americanus, which we designate as CuMT-1, CuMT-2, and CuMT-3, respectively. As a first attempt to fully characterize these proteins, we have determined the sequence of the first 56 amino acids of CuMT-1. The results show this protein to belong to the class I MTs, i.e., related in primary structure to equine renal MT. CuMT-1 cannot transfer its copper to copper-depleted apohemocyanin. CuMT-2 belongs to the same class of MTs as CuMT-1, but CuMT-3 does not. The latter can reactivate lobster hemocyanin containing reduced amounts of Cu(I). Spectroscopic studies show that Cu(I) transfer from CuMT-3 to apohemocyanin initially results in the formation of distorted binuclear- copper sites, which subsequently slowly return to their native stereochemical configuration. Finally, we present evidence that shows that the class I MTs in marine crustacea are involved in the sequestration of elevated levels of heavy-metal ions. These observations strongly suggest that the different forms of MT have different biological functions.
Brouwer, M., and Brouwer-Hoexum, T. (1991). Interaction of copper-metallothionein from the American lobster, Homarus americanus, with glutathione. Arch Biochem Biophys 290, 207-13.
Organisms have harnessed the unique chemistry of copper for a variety of purposes. However, that same chemistry makes this essential metal toxic at elevated concentrations. Metallothioneins (MTs), a family of small metal-binding proteins, are thought to play a crucial role in the regulation of this reactive ion. Here we report that copper- metallothioneins from the American lobster, Homarus americanus, interact with the tripeptide glutathione (gamma-Glu-Cys-Gly). Glutathione in the cytosolic fraction prepared from the digestive gland of the American lobster coelutes with copper-metallothionein during size-exclusion chromatography. The latter protein can be separated into three isoforms by anion-exchange chromatography. All three isoforms belong to the class I MTs. CuMT-I and -II are very similar, whereas CuMT-III is distinct from isoforms I and II. The interaction between glutathione and MT isoforms was examined by ultrafiltration experiments and size-exclusion HPLC. CuMT-III forms a stable 1:1 complex with glutathione, with a dissociation constant of 1 microM. CuMT-I/II makes a transient complex with glutathione, which releases copper as a copper- glutathione complex. This complex can function as the source of Cu(I) in the restoration of the oxygen-binding capacity of copper-free hemocyanin. These studies suggest that metallothionein and glutathione are intricately linked in the biochemistry of copper regulation.
Brouwer, M., and Brouwer-Hoexum, T. (1992). Glutathione-mediated transfer of copper(I) into American lobster apohemocyanin. Biochemistry 31, 4096-102.
Copper in the cytosol of the hepatopancreas of the American lobster, Homarus americanus, occurs as copper-metallothionein [Cu(I)-MT] and as a copper-glutathione complex [Cu(I)-GSH]. The latter can act in vitro as the source of Cu(I) in the reconstitution of lobster apohemocyanin, whereas Cu(I)-MT cannot. Here we report on the mechanism of the GSH- mediated reconstitution. Binding of Cu(I) to apohemocyanin was measured by its effect on the protein's fluorescence, by ultrafiltration experiments and size-exclusion HPLC. Reconstitution of CO and O2 binding was studied using the [Cu(I)...Cu(I)-CO] fluorescence of hemocyanin and its Cu-O2-Cu charge-transfer band as spectral probes. The hemocyanin oligomer has 1 (1.02 +/- 0.09) high-affinity (apparent Kdiss = 1.67 +/- 0.40 microM) external binding site for ionic Cu(I) per subunit. Binding of Cu(I) to this site is fast and reversible and is followed by a slow, irreversible incorporation of copper into the protein matrix. Movement of the first copper through the matrix to the active site is the rate-limiting step in the reconstitution process. Mononuclear copper sites, once formed, are rapidly converted into biologically active, binuclear copper sites. In accordance with this reaction sequence, the restoration of CO/O2 binding by hemocyanin is a first-order reaction with a half-time of 100 +/- 5 min at pH 6.0. Reconstitution is extremely pH-dependent and proceeds best at those pH values where the architecture of the copper pocket of hemocyanin is open as judged from its extremely low affinity for oxygen and its very fast oxygen dissociation rate.(ABSTRACT TRUNCATED AT 250 WORDS).
Brouwer, M., and Brouwer, T. H. (1998). Biochemical defense mechanisms against copper-induced oxidative damage in the blue crab, Callinectes sapidus. Archives of Biochemistry and Biophysics 351, 257-264.
The blue crab (Callinectes sapidus) has a very dynamic copper metabolism associated with the biosynthesis and degradation of its respiratory pigment hemocyanin, In this study we report on the cellular defense mechanisms used by the crab to protect itself from copper toxicity. Short-term copper-exposure studies, conducted by incubating hepatopancreas tissue explants in copper-containing medium, show that copper taken up by the cells during the first 60 min combines with low-molecular- weight copper complex(es), which include Cu(I)-glutathione. Thereafter, copper binds to newly synthesized metallothionein (MT), with a concomitant decrease in Cu(I)-glutathione. Copper does not displace zinc from the endogenous ZnMT pool, Long-term exposure by means of copper-rich diets results in the synthesis of two MT isoforms in the hepatopancreas: CuMT-I and CuP6T-II (D. Schlenk and M. Brouwer, 1991, Aquat. Toxicol. 20, 25-34), Transfer of copper from Cu(I)-glutathione to apoMT-I and apoMT- II can be accomplished in vitro. Cu(I) binding by the two isoforms is very different. Cu(I) binds to apoMT-I in a strictly cooperative manner. No partially filled Cu(I)-thiolate clusters appear to be present, In contrast, the Cu(I)-thiolate clusters in MT-II are formed only after more than four Cu(I) ions are bound. Long-term copper exposure leads to increased activity of two antioxidant enzymes: glutathione peroxidase and manganese superoxide dismutase (SOD), No CuZnSOD is found. Activities of catalase and glutathione reductase and the intracellular levels of glutathione are unaffected by copper. The defense mechanisms are not entirely sufficient for preventing copper-induced oxidative damage. Levels of oxidized lipids are significantly higher in copper-exposed crabs, but oxidized protein levels are nearly the same. (C) 1998 Academic Press.
Brown, J. H., Buchanan, J. S., and Whitley, J. E. (1988). Uptake and excretion of inorganic mercury in the lobster Homarus gammarus (L.) White 1847: long-term effects of exposure to low levels of the metal. Ecotoxicol Environ Saf 15, 125-41.
The uptake and accumulation of inorganic mercury by lobsters, from seawater containing levels of 10 to 100 ppb, was studied over periods of up to 50 days, using radiochemical neutron activation analysis. These results were amplified by the use of radioisotope tracer experiments. It was found that the gills and the green glands accumulated the most mercury and that the metal could be excreted via the urine. Histological studies showed that long-term exposure to mercury resulted in progressive necrosis of the green glands, whereas other organs were unaffected.
Brown, L. D., and Cantino, M. E. (1999). Heterogeneity of the myosin light chains in the abdominal superficial flexor muscle of the American lobster, Homarus americanus. Biophysical Journal 76, A52-A52.
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Bungart, D., Dircksen, H., and Keller, R. (1994). Quantitative determination and distribution of the myotropic neuropeptide orcokinin in the nervous system of astacidean crustaceans. Peptides 15, 393-400.
For quantitative determinations of orcokinin, an indirect, noncompetitive sandwich ELISA was developed. This ELISA is highly specific for orcokinin and the detection limit is 1 fmol. In three astacidean species (Orconectes limosus, Homarus americanus, and Astacus astacus) orcokinin immunoreactivity (OK-IR) was measurable in all parts of the nervous system. Upon normalization to the protein content of the tissue (pmol/mg protein), concentrations were shown to be in the same range in all three species. The distribution of OK-IR in the nervous system is also very similar in the three species. In Orconectes limosus the following values were obtained (in pmol/mg protein): cerebral ganglion 215, optic ganglia in the eyestalk 38, subesophageal ganglion 182. The thoracic ganglia have lower concentrations (35-72) and the abdominal ganglia (AG) 1-5 even lower ones (11-17). In the AG 6 of Orconectes, from which the innervation of the hindgut arises, concentrations are approximately five times higher than in the other AG. In hindgut tissue, relatively high concentrations of 22 pmol/mg were measured, which is in agreement with the demonstrated function of orcokinin as a hindgut excitatory substance. Markedly elevated levels of orcokinin were observed in the AG 6 of Astacus, but not in Homarus. Orcokinin could also be measured consistently and reliably in the hemolymph, where its concentration is approximately 1 x 10(-11) M. These results show that orcokinin may be released into the hemolymph and may act as a hormone, in addition to its role as a locally acting neurotransmitter/modulator.
Burmester, T. (1999). Identification, molecular cloning, and phylogenetic analysis of a non-respiratory pseudo-hemocyanin of Homarus americanus. Journal of Biological Chemistry 274, 13217-13222.
Copper-containing hemocyanins serve to transport oxygen in many arthropod species. Here I describe the identification and cDNA cloning of a structurally closely related non-respiratory pseudo-hemocyanin (PHc) of the American lobster, Homarus americanus, This protein has lost the ability to bind copper and, therefore, oxygen because a histidine residue in copper- binding site A is replaced by tyrosine, Like many arthropod hemocyanins, PHc forms a hexamer, It consists of two different subunit types of 660 and 661 amino acids, respectively, that share a 94.4% sequence identity. Whereas Homarus hemocyanin is produced in the hepatopancreas, PHc is synthesized by the ovaries and the heart tissue. Because different levels of PHc were observed in distinct individuals, I propose an association of the synthesis of this protein with the molting or reproduction cycle, similar to the hexamerins, insect storage proteins that are also related to the hemocyanins, However, phylogenetic analyses show that PHc derived independently from crustacean hemocyanins. Therefore, Homarus PHc is a member of a new class within the growing hemocyanin protein superfamily.
Burns, B. G., Sangalang, G. B., Freeman, H. C., and McMenemy, M. (1984). Isolation and identification of testosterone from the serum and testes of the American lobster (Homarus americanus). Gen Comp Endocrinol 54, 429-32.
Testosterone was isolated and quantified from male lobster serum and testes by solvent extraction, sequential thin-layer chromatography, and high-performance liquid chromatography. The identity of the isolated steroid was established by its isopolarity and isomorphicity with authentic radiolabeled testosterone and its acetate derivative. The concentrations of testosterone were determined by high-performance liquid chromatography, by a double-isotope derivative assay, and by radioimmunoassay. The concentrations of testosterone as determined by the three methods were the same and were 0.3 ng/ml and 14.3 ng/g in lobster serum and testes, respectively.
Burns, B. G., Sangalang, G. B., Freeman, H. C., and McMenemy, M. (1984). Bioconversion of steroids by the testes of the American lobster, Homarus americanus, in vitro. Gen Comp Endocrinol 54, 422-8.
Lobster testes have been demonstrated to contain steroid 20-ketone reductase by their capacity to convert [14C]progesterone to 20 alpha- dihydroprogesterone (20 alpha-DHP). The major product was isopolar and identical with 20 alpha-DHP during thin-layer chromatography, high- pressure liquid chromatography, mass spectrometry, and acetate derivative formation. The vas deferens from the lobster was also capable of the same conversions but to a lesser extent. Lobster testes converted [14C]pregnenolone to a major product identified as 20- dihydropregnenolone (20-DHPe) by mass spectrometry after purification by thin-layer chromatography and high-pressure liquid chromatography. The presence of delta 5,3 beta-ol dehydrogenase and delta 5,delta 4- isomerase in the lobster were also indicated. [14C]Cholesterol was not transformed to steroid hormones by lobster testes under the same experimental conditions.
Burridge, L. E., and Haya, K. (1997). Lethality of pyrethrins to larvae and postlarvae of the American lobster (Homarus americanus). Ecotoxicology and Environmental Safety 38, 150-154.
Pesticide formulations containing pyrethrins are being used to treat salmonids for infestations of the copepod parasites Lepeophtherius salmonis and Caligus elongatus (sea lice). The acute lethality of one such formulation to four larval stages of the American lobster (Homarus americanus), a species of significant economic importance in eastern Canada, was determined. The formulation tested contained 0.06% pyrethrins and 0.6% piperonyl butoxide (a synergist). Stage I larvae (48-h LC50 = 4.42 mu g/liter) were significantly less sensitive than stage II, III, or IV larvae. Stage II larvae (48-h LC50 = 2.72 mu g/liter) were significantly less sensitive than Stage III or IV larvae. Stage III and IV larvae were not significantly different in their response to the pyrethrins formulation (48-h LC50 = 1.39 and 0.73 mu g/liter, respectively). Most published studies using lobster larvae have reported that the earliest larval stage was the most sensitive to chemicals. The results described here indicate that the earliest larval stage is the least sensitive to the pyrethrins formulation. (C) 1997 Academic Press.
Burridge, L. E., Haya, K., Zitko, V., and Waddy, S. (1999). The lethality of Salmosan (Azamethiphos) to American lobster (Homarus americanus) larvae, postlarvae, and adults. Ecotoxicology and Environmental Safety 43, 165-169.
The pesticide formulation Salmosan (47.5% w/w azamethiphos) is currently registered for use, in Canada, to treat salmonids for infestations of the copepod parasites, Lepeophtheirus salmonis and Caligus elongatus (sea lice). Determination was made of the acute lethality of this product to the three larval stages, the first postlarval stage, and the adult of the American lobster (Homarus americanus), a species of significant economic importance in Eastern Canada. The 48-h LC50 (as azamethiphos) is 3.57 mu g/liter for Stage I, 1.03 mu g/liter for Stage II, 2.29 mu g/liter for Stage III, 2.12 mu g/liter for Stage IV (the first postlarval stage), and 139 mu g/liter for adults. These concentrations are not significantly different from each other, although the variability in response is greater in the larval stages than in the postlarvae or adults, These data when interpreted in conjunction with known physical oceanographic data and chemical dispersion studies indicate that single anti- louse treatments are unlikely to result in mortality among lobsters in the vicinity of salmon farms, However, the sublethal effects of this product and the effects of repeated exposures have yet to be determined. (C) 1999 Academic Press.
Bushmann, P., and Atema, J. (1994). Aggression-reducing courtship signals in the lobster, Homarus americanus. Biol Bull 187, 275-6.
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Bushmann, P. J. (1999). Concurrent signals and behavioral plasticity in blue crab (Callinectes sapidus Rathbun) courtship. Biological Bulletin 197, 63-71.
Behavioral flexibility and behavioral regulation through courtship signals may both contribute to mating success. Blue crabs (Callinectes sapidus) form precopulatory pairs after courtship periods that are influenced by female and perhaps male urine-based chemical signals. In this study, male and female crabs were observed in 1.5-m circular outdoor pools for 45 min while the occurrence and sequence of courtship behaviors and pairing outcomes were recorded. These results were then compared with trials in which males or females were blindfolded; lateral antennule (outer flagellum) ablated; blindfolded and lateral antennule ablated; or had received nephropore blocks. The relative importance of visual and chemical sensory systems during blue crab courtship were then determined and urine and non-urine based chemical signals for both males and females were examined. Courtship behaviors varied considerably in occurrence and sequence; no measured behavior was necessary for pairing success. Male or female blindfolding had no effect on any measured behavior. Males and females required chemical information for normal courtship behaviors, yet blocking male or female urine release did not affect courtship behaviors. Males required chemical information to initiate pairing or to maintain stable pairs. Male urine release was necessary for stable pairing, suggesting that male urine signals may be involved in pair maintenance rather than pair formation. Females that could not receive chemical information paired faster and elicited fewer male agonistic behaviors. The results demonstrate a great; variability and flexibility in blue crab courtship, with no evidence for stereotyped behavioral sequences. However, these behaviors appear regulated by urine- and nonurine-based redundant chemical signals emanating from both males and females. Although urine-based signals play roles in blue crab courtship, chemical signals from other sites appear to carry sufficient information to elicit a full range of behavioral responses in males and females.
Butler, M. J., Herrnkind, W. F., and Hunt, J. H. (1997). Factors affecting the recruitment of juvenile Caribbean spiny lobsters dwelling in Macroalgae. Bulletin of Marine Science 61, 3-19.
In south Florida, Caribbean spiny lobsters (Panulirus argus) settle and spend their first few months in macroalgae or seagrass. After a few months, these ''algal-phase'' juveniles emerge from vegetation and, as ''postalgal-phase'' juveniles, seek refuge in crevices, often dwelling in groups. The importance of crevice shelters in determining the abundance of postalgal-phase juvenile spiny lobsters has been studied but we know little about the processes affecting lobster distribution and survival during their cryptic algal-dwelling phase. We found that postlarval supply varied independently of changes in the structure of macroalgal settlement habitat. For this reason, postlarval supply alone can not reliably predict local settlement density. Changes in the size of macroalgal patches in particular tend to increase the variability in settlement density among locations and times. Field and mesocosm experiments indicate that social interactions and individual movements are unlikely to alter the general distribution of algal-phase lobsters established at settlement. But if algal- phase lobsters are aggregated at scales <1 m(2) (e.g., due to patchy settlement), they experience higher mortality than non- aggregated lobsters, as revealed in field experiments where lobsters were tethered alone or in pairs and at varying inter- individual distances. Field manipulations of settlement density indicate that recapture (survival) of microwire tagged algal- phase juveniles is positively associated with features of the habitat that affect lobster density (e.g., site area, macroalgal patch size), but survival and growth of lobsters are unrelated to artificially manipulated settlement density. Collectively, these results imply that the population dynamics of juvenile P. argus dwelling in macroalgae are not typically regulated by density-dependent processes, although density- dependent predation may be locally important in patches when settlement is episodically high.
Byard, E. H., Shivers, R. R., and Aiken, D. E. (1975). The mandibular organ of the lobster, Homarus americanus. Cell Tissue Res 162, 13-22.
The lobster mandibular organ is well vascularized and its polygonal cells are arranged loosely around blood vessels and blood sinuses. Numerous mitochondria and microbodies (peroxisomes) give the acidophilic cytoplasm a finely granular appearance, but there is no evidence of secretory granules. The abundant endoplasmic reticulum is almost entirely agranular and occurs in two morphologically distinct forms: tubular and cisternal. The tubular reticulum is randomly distributed and may represent the site of synthesis and transport of the mandibular organ product. The cisternal reticulum is frequently associated with microbodies. Both forms of endoplasmic reticulum proliferate during mid to late premolt. Mandibular organ ultrastructure closely resembles that of cells known to synthesize steroids or lipids, which suggests that this organ may have a similar function. There is no functional evidence of involvement in molt control in Homarus, but ultrastructural and other evidence suggests an analogy with insect corpus allatum.
Callaway, J. C., and Stuart, A. E. (1999). The distribution of histamine and serotonin in the barnacle's nervous system. Microscopy Research and Technique 44, 94-104.
The use of antisera directed against conjugates of histamine and serotonin has revealed the locations of neurons labeling for these transmitters in the nervous system of barnacles. Photoreceptors label for histamine but not serotonin and also satisfy a number of other criteria indicating that histamine is their neurotransmitter. Photoreceptors also take up radioactively labeled histamine but not serotonin. Within the barnacle's brain no somata are consistently found that label with antiserum against histamine, but one to three pairs of small cells, depending on species, label with antiserum against serotonin. The most impressive serotonin-like immunoreactivity in the brain, however, is in a pair of large fibers ascending through the circumesophageal connectives and ramifying extensively. Within the ventral ganglion, the only other ganglion in the barnacle, ten pairs of cells label with antiserum against histamine. These neurons are confined to the posterior portion of the ganglion but ramify extensively throughout the ganglion. Antiserum against serotonin labels about 15 cell pairs, depending on species, located throughout the ganglion. The positions of the arbors of many of these cells suggest that these amines have a role in modulating either the motor pathways underlying feeding or the visual pathways responsible for the detection of shadows. Microsc. Res. Tech. 44:94-104, 1999. (C) 1999 Wiley-Liss, Inc.
Campbell, P. A., Hartman, A. L., and Abel, C. A. (1982). Stimulation of B cells, but not T cells or thymocytes, by a sialic acid- specific lectin. Immunology 45, 155-62.
Haemolymph of the American lobster, Homarus americanus, contains several lectins. One of these, lobster agglutinin 1 (LAg1) is specific for N-acetylneuraminic acid and agglutinates mouse and human erythrocytes. In addition, this lectin agglutinates peripheral T cells and cortisone-resistant thymocytes, but agglutinates whole thymocytes poorly. Because this material is being used to prepare purified populations of cortical thymocytes, and then to study their maturation, it was important to determine if it is mitogenic for thymocytes and T cells. Thus, the studies described here were conducted to find if LAg1 is a mitogen for mouse lymphocytes, and if so for what cell populations. The data show that purified LAg1, but not purified lobster agglutinin 2 (LAg2) is a mitogen for mouse spleen cells, and that LAg1 is a polyclonal activator. Furthermore, LAg1 is a B-cell mitogen since it stimulates nude spleen cells, nude spleen cells depleted of pre-T cells, and normal spleen cells which have been treated with rabbit anti- mouse brain antiserum and complement. Moreover, LAg1 does not stimulate division by thymocytes or T cells, that is, spleen cells which do not adhere to nylon wool columns. Mitogenic activity of LAg1 but not of LPS is inhibited by N-acetylmannosamine, demonstrating that the mitogenic effects of LAg1 are unlikely to be due to contaminants.
Canli, M., Stagg, R. M., and Rodger, G. (1997). The induction of metallothionein in tissues of the Norway lobster Nephrops norvegicus following exposure to cadmium, copper and zinc: The relationships between metallothionein and the metals. Environmental Pollution 96, 343-350.
Nephrops norvegicus were exposed simultaneously to cadmium, copper and zinc over an 18-day period. Exposure concentrations were control, 1, 5 and 25 mu g litre(-1) for cadmium and copper and 8, 40 and 200 mu g litre(-1) for zinc. Concentrations of cadmium, copper, zinc and metallothionein were measured in homogenates of both the gill and the hepatopancreas. Quantification of metallothionein was carried out by differential pulse polarography. Cadmium concentrations increased significantly in the gill and hepatopancreas of both male and female animals in response to increases in exposure concentration. In contrast, the concentration of copper and zinc increased significantly in the gills of males, but not in females. In the hepatopancreas, neither copper nor zinc resulted in significant changes in concentrations of these metals. Metallothionein concentrations in the gill and hepatopancreas were increased significantly in relation to metal exposure in both males and females. Concentrations of cadmium and metallothionein in both the gill and hepatopancreas of males and females were positively correlated. Copper in the hepatopancreas also showed positive relationships with MT concentrations in males, but not in females. This study suggested that cadmium MTs in the gill and hepatopancreas of Nephrops norvegicus could be used as a sensitive tool to detect cadmium contamination in the lobsters, although this was not true for copper and zinc. (C) 1997 Elsevier Science Ltd.
Cannicci, S., Ruwa, R. K., and Vannini, M. (1997). Homing experiments in the tree-climbing crab Sesarma leptosoma (Decapoda, Grapsidae). Ethology 103, 935-944.
Sesarma leptosoma an East African mangrove-dwelling crab, migrates twice a day from a system of known dens among the roots to well-defined feeding areas in the branches of trees, reaching 15 m high. Field experiments were performed to test whether chemical or visual cues are involved in the orientation and homing of this species to reach their feeding areas. Manipulation of the substratum at branch junctions, in order to alter possible chemical cues, did not affect homing ability in S. leptosoma. Moreover, crabs trained to cross an asymmetrical artificial wooden fork could still follow their preferred directions after (1) the fork branches had been su;itched, (2) the whole fork had been rotated around the trunk, resulting in a right-left inversion, and (3) the inversion of two wide black and white screens hiding most of the canopy from view of the climbing crabs. These results suggest that S. leptosoma may not rely on reference systems such as chemical trail-following and chemical or visual cues from the substratum, but probably depend on complex visual information from the surroundings trunks and/or from the sun's position integrated with junction sequence memory.
Cardi, P., and Nagy, F. (1994). A rhythmic modulatory gating system in the stomatogastric nervous system of Homarus gammarus. III. Rhythmic control of the pyloric CPG. J Neurophysiol 71, 2503-16.
1. Two modulatory neurons, P and commissural pyloric (CP), known to be involved in the long-term maintenance of pyloric central pattern generator operation in the rock lobster Homarus gammarus, are members of the commissural pyloric oscillator (CPO), a higher-order oscillator influencing the pyloric network. 2. The CP neuron was endogenously oscillating in approximately 30% of the preparations in which its cell body was impaled. Rhythmic inhibitory feedback from the pyloric pacemaker anterior burster (AB) neuron stabilized the CP neuron's endogenous rhythm. 3. The organization of the CPO is described. Follower commissural neurons, the F cells, and the CP neuron receive a common excitatory postsynaptic potential from another commissural neuron, the large exciter (LE). When in oscillatory state, CP in turn excites the LE neuron. This positive feedback may maintain long episodes of CP oscillations. 4. The pyloric pacemaker neurons follow the CPO rhythm with variable coordination modes (i.e., 1:1, 1:2) and switch among these modes when their membrane potential is modified. The CPO inputs strongly constrain the pyloric period, which as a result may adopt only a few discrete values. This effect is based on mechanisms of entrainment between the CPO and the pyloric oscillator. 5. Pyloric constrictor neurons show differential sensitivity from the pyloric pacemaker neurons with respect to the CPO inputs. Consequently, their bursting period can be a shorter harmonic of the bursting period of the pyloric pacemakers neurons. 6. The CPO neurons seem to be the first example of modulatory gating neurons that also give timing cues to a rhythmic pattern generating network.
Carlton, J. T., and Cohen, A. N. (1998). Periwinkle's progress: The Atlantic snail Littorina saxatilis (Mollusca : Gastropoda) establishes a colony on a Pacific shore. Veliger 41, 333-338.
The common ovoviviparous and eurytopic Atlantic Ocean periwinkle Littorina (Neritrema) saxatilis (Olivi, 1792) has established reproducing populations in San Francisco flay, California, USA. The first population was discovered in 1993. The probable mechanism of introduction into the Bay is the disposal of seaweeds (the brown algae Ascophyllum nodosum and Fucus vesiculosus) used as transport packing with polychaete worms used for fish bait. These worms, seaweed, and associated periwinkles originate from Maine. An alternative mechanism may be the similar disposal of seaweeds used as packing for imported Atlantic lobsters (Homarus americanus) for the restaurant trade. Littorina saxatilis could occupy a range on the Pacific American coast from Baja California to western Alaska, and as such it would come into direct contact with the consubgeneric Littorina (Neritrema) subrotundata (Carpenter, 1864) (synonym: Littorina newcombiana Hemphill, 1877) and Littorina (Neritrema) sitkana Philippi, 1846, which occur from southern Oregon and north. These latter two species occur in a range of morphological-physiological ecotypes that are closely analogous to those of Littorina saxatilis. Eradication of this snail invasion may be possible because the populations are easily accessed and relatively small. However, no tested eradication methods are known, nor are jurisdictional authority or regulatory issues clear relative to initiating potential removal of this species.
Carvalho, F., Sousa, M., Oliveira, E., Carvalheiro, J., and Baldaia, L. (1998). Ultrastructure of oogenesis in Penaeus kerathurus (Crustacea, decapoda). I. Previtellogenic oocytes. Journal of Submicroscopic Cytology and Pathology 30, 409-416.
Although Malacostracan species represent an important alimentary human resource, the ultra-structure of oogenesis in P. kerathurus remains unknown. Previtellogenic oocytes of Penaeus kerathurus possess a large nucleus with several peripheral nucleoli. The endoplasmic reticulum (ER) is originated from expansions of the nuclear envelope (NE) and contains small dense granules, which are first formed inside the intermembranous space of the NE but are later exported to the ER lumen. Direct vesiculation from the NE and ER then give rise to the Golgi complexes. Small yolk vesicles appear to be mainly formed by vesiculation of the ER, but also receive materials from the Golgi complexes. They contain a fine fibrillar content which seems to originate from decondensation of the small dense granules. Small vesicles and small multivesicular bodies originated from the NE, ER and Golgi complexes, as also myelin figures directly shedded from the NE, fuse together to give origin to large multivesicular bodies (MVB). These organelles, which have an incomplete membrane and appear meshed within nuage materials, give origin, at a later stage, to lipid droplets that are thereafter extruded into the cytoplasm. Neighbouring oocytes exhibit intercellular bridges, the remaining of their surface being surrounded by a single layer of flattened follicular cells. These results show for the first time in Malacostraca the existence of oocyte intercellular bridges, that the ER and Golgi complexes arise from NE activity, that early yolk formation is endogenous and derives from the activity of the NE, ER and Golgi complexes, and that lipid droplets are products of intracellular membrane recycling activity occurring within large multivesicular bodies.
Casasnovas, B., and Meyrand, P. (1995). Functional differentiation of adult neural circuits from a single embryonic network. J Neurosci 15, 5703-18.
The stomatogastric nervous system (STNS) of adult lobsters and crabs generates a number of different rhythmic motor patterns which control different regional movements of the foregut. Since these output patterns are generated by discrete neural networks that, in the adult, are well characterized in terms of synaptic and cellular properties, this system constitutes an ideal model for exploring the mechanisms underlying the ontogeny of neural network organization. The foregut and its rhythmic motor patterns were studied in in vitro STNS nerve-muscle preparations of the embryo and different larval stages of the lobster Homarus gammarus. The development of Homarus comprises a long embryonic stage in ovo followed by three pelagic larval stages prior to the onset of benthic life. During these stages the foregut itself develops slowly from a simple ectodermal invagination that occurs in the embryo. During successive larval stages it progressively acquires all the specialized structures and shape of the adult foregut. In contrast, the STNS is morphologically recognizable at early embryonic stages. In all recorded stages the STNS spontaneously expresses rhythmic motor activity. During development, this activity is progressively restructured, beginning with a single rhythmic motor pattern in the embryo where all the stomodeal muscles are strongly coordinated. In subsequent stages, however, this single pattern is progressively subdivided to give rise eventually to the three discrete rhythmic motor patterns characteristic of the adult STNS. Our data suggest that rather than a dismantling of redundant embryonic and larval neural networks, the different adult networks emerge as a progressive partitioning of discrete circuits from a single embryonic network.
Casasnovas, B., Fenelon, V. S., and Meyrand, P. (1999). Ontogeny of rhythmic motor networks in the stomatogastric nervous system. Journal of Comparative Physiology a-Sensory Neural and Behavioral Physiology 185, 361-365.
We used the lobster Homarus gammarus to study the ontogeny of neural networks involved in rhythmic behaviours. Since in the adult the neural networks belonging to the stomatogastric nervous system and controlling the rhythmic movements of the foregut are well characterised, we have studied them during ontogeny. While this foregut develops slowly throughout embryonic and larval stages, the neuronal population of these motor networks is quantitatively established since the mid- embryonic period. Moreover, in the embryo, this neural population is organised into a single functional network that displays a unique motor output. By contrast, in the adult the same neuronal elements are organised into three neural networks that express independent motor programs. Our results indicate that the multiple adult networks are partitioned progressively from a single embryonic network during development.
Castell, J. D., and Covey, J. F. (1976). Dietary lipid requirements of adult lobsters, Homarus americanus (M.E.). J Nutr 106, 1159-65.
The effects of several dietary lipids on adult American lobster (Homarus americanus) were assessed over a 10 month feeding period. Cod liver oil (CLO) resulted in greater precent weight gains, feed conversion, percent edible meat and higher serum protein and hemocyte counts than either corn oil (CO) or hydrogenated coconut oil (HCO). These differences were probably due to an essential fatty acid (EFA) requirement by the lobster for linolenic series omega3 or other fatty acids present in CLO. The linoleic or omega6 fatty acids of CO appeared to have some sparing effect on several of the EFA deficiency symptoms. It was found that 5% CLO was optimal for mean percent weight gain, molt incidence, feed conversion and hemocyte counts of lobsters. Further increases in dietary CLO to 10% and 15% resulted in no significant improvement of any of the condition indices used. There was a decrease in serum protein and calcium when lobsters were fed a non-saponifiable sterol deficient diet. The addition of 1% cholesterol to the diet raised the serum protein, but resulted in even a greater decrease in the serum calcium level.
Cate, H. S., and Roye, D. B. (1997). Ultrastructure and physiology of the outer row statolith sensilla of the blue crab Callinectes sapidus. Journal of Crustacean Biology 17, 398-411.
The outer crescent row of statolith sensilla of Callinectes sapidus was examined morphologically using scanning and transmission electron microscopy. The number and diameters of axons within the nerve bundle supplying the sensilla were determined. Intracellular injections of Lucifer Yellow were used to examine the central projections of single sensory neurons from the statolith sensilla. In addition, responses of the sensory neurons to displacements of the sensilla were analyzed using electrophysiological techniques. The outer crescent row consists of 7-9 cuticular sensory sensilla. Each has long filamentous extensions projecting from a main shaft. These sensilla ((x) over bar = 73 mu m in length) are innervated by bipolar sensory neurons with large diameter axons ((x) over bar = 29 mu m) passing in the antennular nerve. The afferent fibers from the outer sensilla row appear to be identical and project into median antennular neuropils bilaterally. Extracellular recordings during displacement of single sensilla support the hypothesis that these sensilla are acceleration-sensitive mechanoreceptors. Stimulation of the nerve bundle innervating the outer row statolith sensilla produces short latency, large amplitude depolarizing potentials in antennular withdrawal interneurons, suggesting that deflection of outer row sensilla is capable of initiating antennular withdrawal.
Cattaert, D., and Clarac, F. (1983). Influence of walking on swimmeret beating in the lobster Homarus gammarus. J Neurobiol 14, 421-39.
Influence of walking on swimmeret beating in intact lobsters, Homarus gammarus, has been analyzed using a treadmill experimental device. Belt movement activates both leg stepping and swimmeret beating. The simultaneity of the onset of the two motor systems in this situation is demonstrated to be the result of a startle response initiated when the belt begins to move. This reaction consists of a non-specific motor activity involving several antagonist postural and dynamic muscles. Abdominal extension and vigorous swimmeret beating are the main features of this reaction. The main characteristics of the swimmeret beating as defined by Davis (1969) has been observed here in sequences without walking. However during long walking sequences a very different swimmeret beating pattern occurs. It is suggested that this slow swimmeret beating is completely subordinate to the walking rhythm during sequences of absolute coordination. In more rapid swimmeret beating a relative coordination with leg stepping is very common. The functional meaning of this linkage between legs and swimmerets is discussed.
Cattey, M. A., Gerencser, G. A., and Ahearn, G. A. (1992). Electrogenic H(+)-regulated sulfate-chloride exchange in lobster hepatopancreatic brush-border membrane vesicles. Am J Physiol 262, R255-62.
Transport of [35S]sulfate by brush-border membrane vesicles (BBMV) of lobster (Homarus americanus) hepatopancreas was stimulated by an outwardly directed chloride gradient. In contrast, sulfate uptake was not enhanced by inwardly directed Na+ or K+ transmembrane gradients. An inside-positive membrane potential (valinomycin and K+) stimulated SO4(2-)-Cl- exchange, whereas an inside-negative membrane potential was inhibitory. Sulfate-sulfate exchange was not affected by alterations of transmembrane potential. An inwardly directed proton gradient, or the presence of low bilateral pH, enhanced SO4(2-)-Cl- exchange, but the H+ gradient alone did not stimulate sulfate uptake in chloride- equilibrated BBMV or in vesicles lacking internal Cl-. The stilbenes 4- acetamido-4'-isothiocyanostilbene-2,2'-disulfonic acid (SITS) and 4,4'- diisothiocyanostilbene-2,2'-disulfonic acid (DIDS) strongly inhibited SO4(2-)-Cl- exchange. Sulfate influx occurred by a combination of carrier-mediated transfer, exhibiting Michaelis-Menten kinetics, and nonsaturable "apparent diffusion." 36Cl- influx into sulfate-loaded BBMV was stimulated by an inside-negative transmembrane potential compared with short-circuited vesicles. These results suggest that sulfate-chloride exchange in hepatopancreatic BBMV occurred by an electrogenic carrier mechanism exhibiting a 1:1 flux ratio that was modulated by internal and external H(+)-sensitive regulatory sites. The role of this antiport process in anion secretion is discussed.
Cawthorn, R. J. (1997). Overview of "bumper car" disease--impact on the North American lobster fishery. Int J Parasitol 27, 167-72.
Recent (1993) landings of American lobsters (Homarus americanus) were valued at $294 million (Can.) in Canada and $213 million (Can.) in the United States. However, post-harvest losses are estimated at $50-75 million (10-15%) annually. The lobster fishery is one of the few remaining viable traditional fisheries in eastern North America. "Bumper car" disease of lobsters, caused by the scuticociliate Anophryoides haemophila, can cause significant losses in coldwater impoundments. Apparently epidemics now occur more frequently and with greater severity; surprisingly the epidemiology and economic impacts of "bumper car" disease are not well documented. The ciliate A. haemophila is easily maintained in a cell-free, chemically defined, seawater-based medium at 5 degrees C. Cultured ciliates require longer and more parasites to kill lobsters than those transmitted by intrahaemocoelic injection from lobster-to-lobster. Regardless of source of ciliates, the larger the inoculum, the more rapid the death of lobsters. The pathogenesis of "bumper car" disease is unknown. Horizontal transmission could occur across the thin cuticle of gills or via wounds in the exoskeleton present during moulting of lobsters. Because ciliates are initially sequestered in lobster tissues for an extended period, they are detectable sooner by histological examination of tissues than by direct examination or culture of haemolymph. Additional to indirect fluorescent antibody testing and immunoperoxidase staining of tissues, utilizing monoclonal antibodies prepared to sonicated ciliates, the parasites are readily detected with oligonucleotide probes based on ssu-rDNA of A. haemophila. The prevalence of A. haemophila should be re-evaluated. Ciliates sequester in gill, heart and muscle tissues. Several disinfectants and chemotherapeutants, licensed in North America for veterinary use in food-producing animals, are efficacious against A. haemophila in vitro. A definition of healthy vs ciliate-infected lobsters is being prepared, based on haematology and clinical chemistry of haemolymph. Our novel bar-coded labelling system for aquatic organisms facilitates experimental design and randomization protocols of lobsters. The model of "bumper car" disease will aid study of health and infectious disease processes of lobsters and other crustaceans.
Cazalets, J. R., Nagy, F., and Moulins, M. (1987). Suppressive control of a rhythmic central pattern generator by an identified modulatory neuron in crustacea. Neurosci Lett 81, 267-72.
The activity of the 14 neuron network which organizes the pyloric motor rhythm in the stomatogastric ganglion of the lobster, Homarus gammarus, is controlled by neuromodulatory inputs which have been described as having mainly 'permissive' effects. By contrast, here we identify a neuron, the pyloric suppressor (PS) neuron which exerts a 'suppressive' effect on the pyloric activity. We show that PS neuron discharge can terminate in a long-lasting manner, spontaneous pyloric rhythmic activity. Its effect results from a direct suppression of the endogenous ability of the pyloric pacemaker neurons to produce rhythmic bursts of action potentials. Thus the output of the pyloric neuronal network appears to be finely tuned by neuromodulatory influences having opposite effects.
Cazalets, J. R., Nagy, F., and Moulins, M. (1990). Suppressive control of the crustacean pyloric network by a pair of identified interneurons. II. Modulation of neuronal properties. J Neurosci 10, 458-68.
In the lobster Homarus, the 2 identified PS neurons have a strong suppressive modulatory effect on the activity of the pyloric network in the STG (Cazalets et al., 1990). In the present paper, we consider the effects of PS on individual pyloric neurons isolated from their partners in the network by cell photoinactivation and synaptic blockade. Three types of PS action are described: (1) a transient, EPSP- mediated depolarization of the PD, VD, and AB neurons; (2) a long- lasting hyperpolarization concomitant with a loss of oscillatory properties in the PD and LP neurons; (3) a long-lasting depolarization without modification of oscillatory properties in the PY and IC neurons. The various effects of PS on isolated pyloric cells were consistent with the overall effects of PS on the intact pyloric network.
Cazalets, J. R., Nagy, F., and Moulins, M. (1990). Suppressive control of the crustacean pyloric network by a pair of identified interneurons. I. Modulation of the motor pattern. J Neurosci 10, 448-57.
A pair of identified neuromodulatory neurons, the pyloric suppressor (PS) neurons, can individually and strongly modify the activity of the pyloric network in the stomatogastric nervous system of the lobster Homarus gammarus. The PS neurons are identified by the location of their somata in the inferior ventricular nerve, their axonal projections, and their effects on pyloric network activity in vitro. Discharge of a PS neuron evokes large EPSPs in the pyloric dilator (PD) neurons and a long-lasting cessation of rhythmic activity in the neurons that control movements of the pyloric filter: PD, lateral pyloric (LP), and pyloric (PY). This cessation of rhythmic activity can outlast by several 10s of seconds a brief discharge of PS lasting only a few seconds. The different neurons of the pyloric filter do not exhibit the same sensitivity to the suppressive effects of PS, with the LP neuron being the most sensitive. Tonic discharge in PS induces graded alterations in the pyloric pattern, depending on its firing frequency. At low (less than 5 Hz) discharge frequencies, PS provokes changes in phase relationships and duration of bursting in pyloric neurons. A slight increase in PS frequency suppresses the rhythmic activity of some pyloric neurons, resulting in a switch from a triphasic to a biphasic pattern. At higher (greater than 10 Hz) PS firing frequencies, rhythmic activity in all the pyloric neurons, including the pacemakers (PD, anterior burster), is abolished, except in cells (ventricular dilator, inferior cardiac) controlling the pyloric valve. We conclude that a central pattern generator is not only subject to activating modulatory control, but may also be the target of suppressive inputs that are themselves able to provoke functional reconfigurations of the network.
Chan, S. M., Chen, X. G., and Gu, P. L. (1998). PCR cloning and expression of the molt-inhibiting hormone gene for the crab (Charybdis feriatus). Gene 224, 23-33.
A PCR-based genomic DNA walking technique was used to clone the gene for the molt-inhibiting hormone of the crab, Charybdis feriatus. Several overlapping genomic clones were isolated, and the MIH gene for the crab was reconstructed. DNA sequence determination of the overlapping clone reveals that the MIH gene spans 4.3 kb and consists of three exons and two introns. Exons 1 and 2 carry a coding sequence for the signal peptide, and exons 2 and 3 consist of coding sequence for the mature peptide. The exon-intron boundary of the crab MIH gene also follows the 'GT-AG rule' for the splice donor and acceptor. The deduced amino acid sequence of MIH shows the highest overall similarity to those of the crabs, Callinectes sapidus and Carcinus maenas, and the gonad-inhibiting hormone (GIH) of the lobster. The putative polyadenylation signal is approximately 1.0 kb 3' downstream of the termination codon (TGA). Genomic Southern blot analysis indicates that few genomic fragments were hybridized to the cDNA probe. The 5' flanking region contains a putative promoter with several putative cis elements similar to some vertebrate neuropeptide genes. The 530-bp flanking region was subcloned separately to two promoterless reporter plasmids carrying either the Green Fluorescent Protein gene (GFP) or the Choramphenicol Acetyltransferase gene (CAT). The DNA constructs were transfected into insect cells (Sf21) and mouse pituitary cells (GH4ZR7), respectively. Green fluorescent protein was detected in some of the transfected insect cells, and expression of the CAT was detected in cells transfected with DNA constructs containing the crab promoter. By RT-PCR, MIH transcripts can be detected in the eyestalk of shrimp in intermolt, early premolt, late premolt stages and females that brood their eggs. It can also be found in the brain, but not in the ovary, hepatopancreas, muscle and epidermis. During early larval development, MIH mRNA can be detected in the pre-hatched and the newly hatched larvae. Unlike the adult, the expression of the MIH in the larvae is exclusively in the brain. (C) 1998 Elsevier Science B.V. All rights reserved.
Chang, E. S., Bruce, M. J., and Newcomb, R. W. (1987). Purification and amino acid composition of a peptide with molt- inhibiting activity from the lobster, Homarus americanus. Gen Comp Endocrinol 65, 56-64.
A peptide was isolated and purified from sinus glands of the lobster, Homarus americanus, that was able to decrease circulating titers of ecdysteroids and increase the molt interval of eyestalk-ablated juvenile lobsters. This molt-inhibiting activity was demonstrated to consist of two very closely related peptides by means of high- performance liquid chromatography and gel electrophoresis. By means of amino acid analyses, a molecular weight of approximately 8700 was obtained.
Chang, E. S., Prestwich, G. D., and Bruce, M. J. (1990). Amino acid sequence of a peptide with both molt-inhibiting and hyperglycemic activities in the lobster, Homarus americanus. Biochem Biophys Res Commun 171, 818-26.
A hydrophobic peptide of 71 residues was isolated from lobster sinus gland extracts that prolonged intermolt periods and lowered ecdysteroid titers in juvenile lobsters. Removal of the N-terminal pyroglutamyl residue allowed sequencing of 30 of the first 36 residues. Additional data were obtained from HPLC-purified fragments from endoproteinase cleavages (Lys-C, Glu-C, Arg-C, Asp-N), and carboxypeptidase Y digestion. This is the first reported amino acid sequence of a crustacean molt-inhibiting hormone. This peptide also has significant hyperglycemic activity.
Chang, E. S., Keller, R., and Chang, S. A. (1998). Quantification of crustacean hyperglycemic hormone by ELISA in hemolymph of the lobster, Homarus americanus, following various stresses. General and Comparative Endocrinology 111, 359-366.
An ELISA was developed for the crustacean hyperglycemic hormone (CHH) from the lobster, Homarus americanus. It is sensitive to as little as 0.2 fmol of peptide. The assay was used to measure CHH in the hemolymph of intact lobsters after various environmental stresses. Increases in CHH were observed following emersion, exposure to high temperatures (23 degrees and 28 degrees C), and salinity stress (50 and 150% seawater). During emersion, concentrations of hemolymph glucose increased concomitantly with increases in CHH. Significant levels of hemolymph CHH were also measured in lobsters that had been eyestalk-ablated. These latter observations indicate that there may be a source of CHH other than the X-organ/sinus gland in the lobster. (C) 1998 Academic Press.
Chang, E. S., Chang, S. A., Beltz, B. S., and Kravitz, E. A. (1999). Crustacean hyperglycemic hormone in the lobster nervous system: Localization and release from cells in the subesophageal ganglion and thoracic second roots. Journal of Comparative Neurology 414, 50-56.
Crustacean hyperglycemic hormones (CHHs) are neuropeptides involved in the regulation of hemolymph glucose. The primary source of CHHs has been identified as the neurosecretory neurons of the eyestalk X-organ and its associated neurohemal organ, the sinus gland. We have identified another source of CHH-like peptides in the nervous system. With the use of immunocytochemistry, cells in the second roots of the thoracic ganglia have been observed to stain positively for CHH-reactive material. We also identified a pair of cells in the subesophageal ganglion that contain large amounts of CHH- reactive material. Depolarization of these cells with elevated potassium mediates a calcium-dependent release of CHH-like material from the ganglion as quantified with an enzyme-linked immunosorbent assay (ELISA). (C) 1999 Wiley-Liss, Inc.
Chang, E. S., Chang, S. A., Keller, R., Reddy, P. S., Snyder, M. J., and Spees, J. L. (1999). Quantification of stress in lobsters: Crustacean hyperglycemic hormone, stress proteins, and gene expression. American Zoologist 39, 487-495.
Various methods for the quantification of stress in crustaceans have been developed in our laboratory. An ELISA was developed for the crustacean hyperglycemic hormone (CHH) from the lobster, Homarus americanus. It is sensitive to as little as 0.2 fmol of peptide. Increases in hemolymph CHH were observed following emersion. Significant levels of hemolymph CHH were also measured in lobsters that had been eyestalk-ablated, It was observed that these animals continued to produce CHH, even though the heretofore only known source of CHH had been removed. Portions of the central nervous system, from both intact and eyestalk-ablated lobsters were observed to contain significant amounts of CHH. A cDNA library was constructed from eyestalk neural tissue of H. americanus. With the use of PCR, a 171 bp probe was isolated and purified, This probe was labeled and used to examine levels of CHH expression in the central nervous system (CNS) and in eyestalk neural tissue at different periods of the lobster molt cycle, CHH mRNA is present throughout the CNS, In the eyestalk, it is undetectable in postmolt, low in intermolt, and high in premolt, Stress proteins, also known as heat shock proteins (HSPs), are a highly conserved class of proteins which show elevated transcription during periods of stress in organisms as phylogenetically divergent as bacteria and humans. Using RT- PCR, we have partially cloned the lobster HSP90 gene. A 380 bp probe was P-32-labeled and hybridized with northern blots of midgut gland total RNA from heat-shocked lobsters, A 2 hr acute heat shock from 15 degrees C (ambient water temperature) to 28 degrees C resulted in a 6.0-fold induction of HSP90 after 6 hr of recovery at 15 degrees C. A northern analysis of RNA isolated from the midgut glands of lobsters injected with 10 mu g of the molting hormone 20-hydroxyecdysone displayed a 2.1- fold induction of HSP90 RNA 48 hr postinjection.
Chapelle, S., and Dandrifosse, G. (1972). [Effect of different salts on beta-hydroxyacyl-CoA dehydrogenase and beta-acetoacetyl-CoA thiolase activities in muscles of Eriocheir sinensis and Homarus vulgaris]. Arch Int Physiol Biochim 80, 213-27.
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Charland, N., Kellens, J. T., Caya, F., and Gottschalk, M. (1995). Agglutination of Streptococcus suis by sialic acid-binding lectins. J Clin Microbiol 33, 2220-1.
The 35 Streptococcus suis capsular-type reference strains as well as 45 field strains of type 2 were tested with sialic acid-binding lectins from Sambucus nigra (SNA I), Triticum vulgaris, Maackia amurensis, Homarus americanus, and Limax flavus. Only types 1, 1/2, 2, 14, 15, and 16 agglutinated with SNA I and/or the T. vulgaris lectin. All field strains agglutinated only with SNA I. Reaction with SNA I was probably due to the sialic acid moiety since it disappeared after sialidase treatment. These results confirm the presence of sialic acid in S. suis with the possible terminal sequence N-acetylneuraminic acid- alpha(2,6)GalNAc.
Charmantier, G., Charmantier-Daures, M., and Aiken, D. E. (1984). Neuroendocrine control of hydromineral regulation in the American lobster Homarus americanus H. Milne-Edwards 1837 (Crustacea, Decapoda). 1. Juveniles. Gen Comp Endocrinol 54, 8-19.
Juvenile lobsters survive well in salinities above 10.2% (300 mOsm/kg), and their osmotic and ionic (Cl-, Na+, Ca2+) regulation in dilute sea water is slightly hyperosmotic, similar to that of adults. Approximately a month after eyestalk ablation, osmotic and ionic (Cl-, Na+) regulation becomes isosmotic, water content increases, and survival rate in dilute sea water declines, but these changes can be partially reversed by implantation of eyestalk neuroendocrine tissue. Regulation of Ca2+, in contrast, is only slightly affected by eyestalk ablation. These results indicate that osmotic regulation and regulation of hemolymph Na+ and Cl- concentrations are at least partly controlled by eyestalk neuroendocrine factors in this species.
Charmantier, G., Charmantier-Daures, M., and Aiken, D. E. (1984). Neuroendocrine control of hydromineral regulation in the American lobster Homarus americanus H. Milne-Edwards, 1837 (Crustacea, Decapoda). 2. Larval and postlarval stages. Gen Comp Endocrinol 54, 20-34.
Sodium regulation in Homarus americanus changes from isoionic in Stage III to slightly hyperionic in Stage IV, and this is paralleled by improved survival of Stage IV lobsters in dilute media. Bilateral eyestalk ablation converts Stage IV and V lobsters to isoionic sodium regulation, but implantation of Stage IV or V eyestalk neuroendocrine tissue restores their normal hyperionic regulation. These results indicate that sodium regulation is controlled from Stage IV by eyestalk neuroendocrine factors. It is suggested that these changes between stages are part of a true metamorphosis that occurs between the last larval stage (III) and the first postlarval stage (IV).
Charmantier, G., Charmantier-Daures, M., and Aiken, D. E. (1988). Larval development and metamorphosis of the American lobster Homarus americanus (Crustacea, Decapoda): effect of eyestalk ablation and juvenile hormone injection. Gen Comp Endocrinol 70, 319-33.
Removal of eyestalks of Homarus americanus on different days and molting stages during larval development revealed that eyestalk tissue is involved in the larval and postlarval molting rhythm and in preparation for metamorphosis as early as the end of Stage II. Eyestalk removal in stages II and III reduced the duration of larval and postlarval stages. Eyestalk removal up to the end of Stage II delayed the completion of metamorphosis by one or two molts and caused additional development stages (designated IVa, IV', and V'). In this study, the critical stage for eyestalk ablation to delay metamorphosis occurred at the end of molt stage D1 of larval Stage II (the seventh day of development at 20 degrees). Injection of juvenile hormone before the critical stage resulted in a few intermediate stage IV' animals. This study demonstrates the involvement of eyestalk neuroendocrine tissue in the control of metamorphosis and investigates a possible involvement of juvenile hormone.
Charmantier, G., Charmantier-Daures, M., and Aiken, D. E. (1989). [Human somatotropin stimulates the growth of young American lobsters, Homarus americanus (Crustacea, Decapoda)]. C R Acad Sci III 308, 21-6.
Larval and postlarval lobsters, injected with human somatotropin (STH, or growth hormone), grew at a more rapid rate than untreated control animals over succeeding molts. Their mean carapace length was significantly longer than that of controls and they were heavier, although the moisture content of treated and control animals was similar. Injected STH increased the growth rate of individual animals by 10 to 20%. This is the first evidence for a growth enhancing effect of human somatotropin on a Crustacean.
Charmantier, G. (1998). Ontogeny of osmoregulation in crustaceans: a review. Invertebrate Reproduction & Development 33, 177-190.
From the results of studies conducted from the 1960s, three patterns of ontogeny of postembryonic osmoregulation in crustaceans may be distinguished: (1) osmoregulation varies little with developmental stage and the adults are often weak regulators or osmoconformers; (2) the adult type of osmoregulation is established in the first postembryonic stage; (3) metamorphosis marks the appearance of the adult type of osmoregulation. The occurrence of osmoregulation is based on efficient ionic regulation (mainly of Na+ and Cl-) and increased levels of Na+-K+ ATPase activity. Osmoregulatory epithelia may appear at different times of development and at different locations of the branchial chamber. These events are inter-related, and are correlated with changes in salinity tolerance. In species the eggs of which are exposed to the external medium, either embryos are osmotically protected by the egg envelopes, or the egg membranes and/or the embryos acquire the ability to osmoregulate. When embryos develop in incubating pouches enclosed in the female's body, where they are osmotically protected, they may also become progressively able to osmoregulate. Throughout the development of crustaceans, osmoregulation appears as a key adaptative factor to one or several habitats.
Charmantier, G., and Charmantier-Daures, M. (1998). Endocrine and neuroendocrine regulations in embryos and larvae of crustaceans. Invertebrate Reproduction & Development 33, 273-287.
This review deals with the studies which have been conducted for the past 30 years on the endocrine and neuroendocrine regulations in embryos and larvae of crustaceans, mostly in decapods. Y-organs, mandibular organs and the X-organ sinus gland complex of the eyestalks are present in the first post- embryonic instar of most investigated species. Y-organs, the X- organs and the sinus glands have also been located in embryos of a few species. Larval molting appears to be regulated in a way similar to that in adults involving a MIH-ecdysteroid system. Evidence points to a control of metamorphosis through the eyestalks. Experimental evidence points to a neuroendocrine control of changes in pigmentation and of osmoregulation. Progress in the isolation and characterization of the hormones and neurohormones controlling these metabolic changes in adults should help and promote further research on regulation during the embryonic and early postembryonic development.
Charmantier-Daures, M., Charmantier, G., Janssen, K. P., Aiken, D. E., and van Herp, F. (1994). Involvement of eyestalk factors in the neuroendocrine control of osmoregulation in adult American lobster Homarus americanus. Gen Comp Endocrinol 94, 281-93.
Osmoregulatory capacity (OC) decreased by approximately 50% after eyestalk ablation in adult Homarus americanus when in dilute media. OC was used to assay sinus gland extracts. Injection of total extracts and of some HPLC-separated fractions of sinus glands into destalked lobsters increased OC. One of the described crustacean hyperglycemic hormone isoforms influences osmoregulation. Another fraction of the sinus gland extracts modifies osmoregulation but its nature remains unknown. Variations in OC were examined in response to ecdysterone, Phe- Met-Arg-Phe-NH2, and atrial natriuretic factor but effects were minimal.
Charmantier-Daures, M., and Segonzac, M. (1998). Organ of Bellonci and sinus gland in three decapods from Atlantic hydrothermal vents: Rimicaris exoculata, Chorocaris chacei, and Segonzacia mesatlantica. Journal of Crustacean Biology 18, 213-223.
Crustaceans of the hydrothermal vent field of the Mid-Atlantic Ridge present graded variations of eye structure. In the shrimps Rimicaris exoculata and Chorocaris chacei, external eyestalks are missing or reduced and conventional compound eyes are lacking. The crab Segonzacia mesatlantica has small eyestalks. Our objective was to localize and describe the organ of Bellonci and the sinus gland usually included in the eyestalks. In Rimicaris exoculata and Chorocaris chacei, the organs of Bellonci are well developed and contain onion body- like structures. They are located in front of the cerebral ganglia close to the hemiellipsoid bodies, a position unusual among decapods. Each organ of Bellonci extends to a complex cuticular structure which is probably a sensory pore. In the two shrimps, the optic lobes are located within the brain. The four optic neuropile layers are present. The sinus gland is small and cupula-shaped, with usual histological features. It is located between the interna and externa medullae, adjacent to a hemolymph lacuna. In Segonzacia mesatlantica, the eyestalks contain massive nervous masses with numerous and complex chiasmata from which only the lamina ganglionaris is slightly separated. The organ of Bellonci and the sinus gland are both located inside the eyestalks on opposite sides. The organ of Bellonci contains onion bodies but no distinguishable sensory pore. The sinus gland is large with visible patches of neurosecretory secretions and is surrounded by a thick layer of connective tissue.
Chen, J. C., and Chen, J. S. (1998). Acid-base balance, ammonia and lactate levels in the haemolymph of Penaeus japonicus during aerial exposure. Comparative Biochemistry and Physiology a-Molecular and Integrative Physiology 121, 257-262.
Acid-base balance, ammonia and L-lactate levels were measured in the haemolymph of Penaeus japonicus subjected to aerial exposure at 6, 12 and 18 degrees C for up to 12-48 h. About 90% of P. japonicus survived at 6 and 12 degrees C after 36 h of aerial exposure, whereas no prawns survived at 18 degrees C after 24 h. Haemolymph pH and OH-/H+ decreased at 18 degrees C, but increased at 6 and 12 degrees C with increased exposure time. Haemolymph P-CO2, HCO3-, TCO2 (total carbon dioxide) and L-lactate levels were directly related to exposure time. After a 12-h emersion at 18 degrees C, P. japonicus accumulated, ammonia and L-lactate up to 0.645 and 11.77 mmol l(-1), which was three and four times higher than those at 6 degrees C, respectively. The ability of P. japonicus at low temperature (6 and 12 degrees C) to survive longer than those at 18 degrees C is considered to be due to lower accumulation of ammonia and L- lactate, and compensation buffer of HCO3.- (C) 1998 Elsevier Science Inc. All rights reserved.
Chiang, R. G., and Govind, C. K. (1984). Decrease in transmitter output and synaptic ultrastructure at lobster neuromuscular terminals with decentralization. Brain Res 299, 265-79.
The effects of decentralization on the physiology and ultrastructure of neuromuscular terminals were examined by transecting the single excitor axon to the distal accessory flexor muscle in the walking legs of lobsters (Homarus americanus). Decentralization caused a reduction in the amplitude of the excitatory junctional potential without altering the resting potential or input resistance of the muscle fiber thereby suggesting a reduction in transmitter release. Confirmation was obtained by recording of synaptic currents at focal sites which showed failure of transmission and a reduced amplitude on decentralized fibers compared to their intact counterparts on the contralateral leg. The mean quantal content of synaptic transmission decreased approximately 2- 7-fold at these decentralized sites compared to their intact counterparts. The ultrastructure of these identified sites was examined with serial section electron microscopy. There are few if any qualitative changes in synaptic ultrastructure between decentralized and control terminals. However, quantitatively there were changes in synaptic ultrastructure which were progressive in nature depending on the severity of the reaction to decentralization. Thus terminals showing a moderate decline in quantal content were characterized by a reduction in the number of presynaptic dense bars and synapses. Terminals showing a severe drop in transmitter release showed in addition to the above changes, a reduction in the size of synapses and terminals. These results show a progression in the loss of the structural parameters controlling transmitter release. Finally synaptic vesicles and mitochondria did not reveal any consistent or marked change with decentralization.
Chou, C. L., Guy, R. D., and Uthe, J. F. (1991). The reactivity of EDTA, copper ion, and copper citrate with metallothioneins isolated from the digestive gland of cadmium- contaminated lobster (Homarus americanus). Sci Total Environ 105, 61-71.
The reactivity of EDTA, Cu2+, and copper citrate with two metallothionein preparations (MT-1 and MT-2) isolated from the digestive gland of Cd-contaminated American lobster (Homarus americanus) was studied. Under pseudo-first-order conditions, metallothioneins reacted with EDTA for removal of Cd2+ in a multiphasic manner. Cadmium(+II) removal by Cu2+ was complex and non- stoichiometric, suggesting different binding sites. Rabbit liver metallothionein reacted similarly. Cadmium removal from lobster metallothionein by copper citrate was slow and triphasic in nature. EDTA removed Cu2+ from lobster metallothionein very slowly.
Chou, C. L., Guy, R. D., and Uthe, J. F. (1991). Isolation and characterization of metal-binding proteins (metallothioneins) from lobster digestive gland (Homarus americanus). Sci Total Environ 105, 41-59.
Two metallothionein (low-molecular-weight, metal-binding proteins) preparations, MT-1 and MT-2, have been isolated from the digestive gland of American lobster (Homarus americanus) contaminated with Cd. MT- 1 contains Cd- and Cu-binding proteins, whereas MT-2 is a reasonably pure Cd-binding protein. The properties of MT-1 and MT-2 with respect to amino acid and elemental compositions, heat stabilities, polarographic, high-performance liquid chromatography (HPLC), and isoelectric focussing behaviors are reported. Lobster metallothioneins share a number of similarities with mammalian metallothioneins with respect to the presence of Cd and Cu, apparent molecular weights, amino acid compositions, UV absorption spectra at various pH, and polarographic behavior, but differ substantially in their electrophoretic behavior.
Chou, C. L., and Uthe, J. F. (1995). Thallium, uranium, and 235U/238U ratios in the digestive gland of American lobster (Homarus americanus) from an industrialized harbor. Bull Environ Contam Toxicol 54, 1-7.
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Chung, J. S., Wilkinson, M. C., and Webster, S. G. (1998). Amino acid sequences of both isoforms of crustacean hyperglycemic hormone (CHH) and corresponding precursor-related peptide in Cancer pagurus. Regulatory Peptides 77, 17-24.
Both isoforms of the crustacean hyperglycemic hormone (CHH) and corresponding crustacean hyperglycemic hormone precursor- related peptide (CPRP) derived from HPLC-purified sinus gland extracts from the edible crab Cancer pagurus were fully characterised by microsequencing and mass spectrometry. The amino acid sequences of the CHH isoforms were almost identical except that the N-terminus of the minor isoform (CHH-I), was glutamine rather than pyroglutamate in the major isoform (CHH- II). Both CHH isoforms were of similar biological activity, as tested by in vivo hyperglycemia bioassays and in vitro repression of ecdysteroid synthesis. Comparison with other published CHH and CPRP sequences show that for crabs, these peptides form a distinct group, that the presence of CHH isoforms with free and blocked N-termini seems unique to crabs. It is argued that this phenomenon reflects a slow post- translational modification in sinus gland neurosecretory terminals. This study appears to complete the entire sinus gland inventory of functionally and structurally characterised CHH-related peptides in a crab. (C) 1998 Elsevier Science B.V. All rights reserved.
Chung, A. C. K., Durica, D. S., and Hopkins, P. M. (1998). Tissue-specific patterns and steady-state concentrations of ecdysteroid receptor and retinoid-X-receptor mRNA during the molt cycle of the fiddler crab, Uca pugilator. General and Comparative Endocrinology 109, 375-389.
In the fiddler crab, Uca pugilator, we have investigated the temporal expression of receptors in various tissues using probes that encode Uca ecdysteroid receptor (UpEcR) and retinoid-X-receptor (UpRXR) gene homologs. During molt stages C-4 through D1-4, UpEcR and UpRXR transcripts are expressed in regenerating limb buds, gills, eyestalks, hypodermis, hepatopancreas, muscle from nonregenerating walking legs, and the large cheliped. Some of these tissues have not previously been recognized as ecdysteroid-target tissues. Levels of ecdysteroids in the hemolymph fluctuate significantly during the molt cycle of U. pugilator. The variation in steady-state concentrations of UpEcR transcripts in tissues from C-4 to D1-4 implies molt cycle-related differences in the potential of these tissues to respond to changing titers of ecdysteroids in the hemolymph. In singly autotomized crabs, highest concentrations of UpEcR transcript in some tissues did not coincide with the highest levels of circulating ecdysteroids, suggesting that UpEcR expression in these tissues is not dependent on high ecdysteroid titers and may be induced by low or rising concentrations of ecdysteroids. UpEcR and UpRXR genes were expressed simultaneously in tissues, supporting the possibility of heterodimerization for EcR and RXR in vivo. In some tissues, however, levels of transcripts differed, suggesting other possible receptor interactions. Moreover, UpEcR expression in tissues from multiply autotomized crabs differed from the expression patterns in tissues from singly autotomized crabs. (C) 1998 Academic Press.
Clancy, M., and Cobb, J. S. (1997). Effect of wind and tidal advection on distribution patterns of rock crab Cancer irroratus megalopae in Block Island Sound, Rhode Island. Marine Ecology-Progress Series 152, 217-225.
The planktonic period of benthic marine invertebrates can significantly affect distribution patterns of benthic juveniles. In this paper we address the relationship between advection and the subsequent abundance of planktonic megalopae of the rock crab Cancer irroratus in Block Island Sound, Rhode Island (USA), over an 8 yr period. At small scales (several meters distance with samples taken simultaneously), megalopae were found to be similarly distributed; at larger temporal (lens of minutes) and spatial scales (hundreds of meters) megalopae were very patchy, which indicates a complex, highly variable pattern of abundance typical of planktonic systems. Using the receptor-mode trajectory capability of OILMAP, a numerical hydrodynamic model, we detected a significant relationship between the direction of transport prior to collection (as predicted by the model) and the subsequent catch of megalopae. We argue that rock crab megalopae are often advected tens of kilometers over short time spans and are concentrated on south-facing shores in Block Island Sound. Further, enhanced planktonic delivery to our study area results in large pulses of individuals to the benthos. Directional transport would be an effective larval delivery strategy even ii rock crab megalopae were subject to lower advection, perhaps owing to a deep vertical distribution; a significant relationship between transport direction and collection date was detected even under a lower advective regime.
Clemens, S., Meyrand, P., and Simmers, J. (1998). Feeding-induced changes in temporal patterning of muscle activity in the lobster stomatogastric system. Neuroscience Letters 254, 65-68.
In the lobster Homarus gammarus, rhythmic masticatory movements of the foregut gastric mill are generated by a small neural network in the stomatogastric ganglion. We have used EMG recordings from intact animals to analyse gastric network output in relation to cycle period before and after feeding. In pre-prandial conditions, muscles controlling lateral teeth closure and medial tooth protraction (driven by MG and GM motor neurons, respectively) express relatively constant, return stroke-like burst durations, but change to a variable-duration power stroke-like phenotype after feeding. In contrast, the LPG neuron-innervated lateral teeth opener muscle switches from power stroke to return stroke-like behavior. Thus alternate phases within a single motor program may invert their temporal properties according to the behavioral situation. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.
Clemens, S., Massabuau, J. C., Legeay, A., Meyrand, P., and Simmers, J. (1998). In vivo modulation of interacting central pattern generators in lobster stomatogastric ganglion: Influence of feeding and partial pressure of oxygen. Journal of Neuroscience 18, 2788-2799.
The stomatogastric ganglion (STG) of the European lobster Homarus gammarus contains two rhythm-generating networks (the gastric and pyloric circuits) that in resting, unfed animals produce two distinct, yet strongly interacting, motor patterns. By using simultaneous EMG recordings from the gastric and pyloric muscles in vivo, we found that after feeding, the gastropyloric interaction disappears as the two networks express accelerated motor rhythms. The return to control levels of network activity occurs progressively over the following 1-2 d and is associated with a gradual reappearance of the gastropyloric interaction. In parallel with this change in network activity is an alteration of oxygen levels in the blood, In resting, un fed animals, arterial partial pressure of oxygen (PO2) is most often between 1 and 2 kPa and then doubles within 1 hr after feeding, before returning to control values some 24 hr later. In vivo, experimental prevention of the arlerial PO2 increase after feeding leads to a slowing of pyloric rhythmicity toward control values and a reappearance of the gastropyloric interaction, without apparent effect on gastric network operation. Using in vitro preparations of the stomatogastric nervous system and by changing oxygen levels uniquely at the level of the STG within the range observed in the intact animal, we were able to mimic most of the effects observed in vivo. Our data indicate that the gastropyloric interaction appears only during a "free run" mode of foregut activity and that the coordinated operation of multiple neural networks may be modulated by local changes in oxygenation.
Clemens, S., Combes, D., Meyrand, P., and Simmers, J. (1998). Long-term expression of two interacting motor pattern- generating networks in the stomatogastric system of freely behaving lobster. Journal of Neurophysiology 79, 1396-1408.
Rhythmic movements of the gastric mill and pyloric regions of the crustacean foregut are controlled by two stomatogastric neuronal networks that have been intensively studied in vitro. By using electromyographic recordings from the European lobster, Homarus gammarus, we have monitored simultaneously the motor activity of pyloric and gastric mill muscles for less than or equal to 3 mo in intact and freely behaving animals. Both pyloric and gastric mill networks are almost continuously active in vivo regardless of the presence of food. In unfed resting animals kept under "natural-like" conditions, the pyloric network expresses the typical triphasic pattern seen in vitro but at considerably slower cycle periods (2.5-3.5 s instead of 1-1.5 s). Gastric mill activity occurs at mean cycle periods of 20-50 s compared with 5-10 s in vitro but may suddenly stop for up to tens of minutes, then restart without any apparent behavioral reason. When conjointly active, the two networks express a strict coupling that involves certain but not all motor neurons of the pyloric network. The posterior pyloric constrictor muscles, innervated by a total of 8 pyloric (PY) motor neurons, are influenced by the onset of each gastric mill medial gastric/lateral gastric (MG/LG) neuron powerstroke burst, and for one cycle, PY neuron bursts may attain >300% of their mean duration. However, the duration of activity in the lateral pyloric constrictor muscle, innervated by the unique lateral pyloric (LP) motor neuron, remains unaffected by this perturbation. During this period after gastric perturbation, LP neuron and PY neurons thus express opposite burst-to-period relationships in that LP neuron burst duration is independent of the ongoing cycle period, whereas PY neuron burst duration changes with period length. In vitro the same type of gastro- pyloric interaction is observed, indicating that it is not dependent on sensory inputs. Moreover, this interaction is intrinsic to the stomatogastric ganglion itself because the relationship between the two networks persists after suppression of descending inputs to the ganglion. Intracellular recordings reveal that this gastro-pyloric interaction originates from the gastric MG and LG neurons of the gastric network, which inhibit the pyloric pacemaker ensemble. As a consequence, the pyloric PY neurons, which are inhibited by the pyloric dilator (PD) neurons of the pyloric pacemaker group, extend their activity during the time that PD neuron is held silent. Moreover, there is evidence for a pyloro-gastric interaction, apparently rectifying, from the pyloric pacemakers back to the gastric MG/LG neuron group.
Clemens, S., Combes, D., Meyrand, P., and Simmers, J. (1998). Long-term expression of two interacting motor pattern-generating networks in the stomatogastric system of freely behaving lobster. J Neurophysiol 79, 1396-408.
Rhythmic movements of the gastric mill and pyloric regions of the crustacean foregut are controlled by two stomatogastric neuronal networks that have been intensively studied in vitro. By using electromyographic recordings from the European lobster, Homarus gammarus, we have monitored simultaneously the motor activity of pyloric and gastric mill muscles for 300% of their mean duration. However, the duration of activity in the lateral pyloric constrictor muscle, innervated by the unique lateral pyloric (LP) motor neuron, remains unaffected by this perturbation. During this period after gastric perturbation, LP neuron and PY neurons thus express opposite burst-to-period relationships in that LP neuron burst duration is independent of the ongoing cycle period, whereas PY neuron burst duration changes with period length. In vitro the same type of gastro- pyloric interaction is observed, indicating that it is not dependent on sensory inputs. Moreover, this interaction is intrinsic to the stomatogastric ganglion itself because the relationship between the two networks persists after suppression of descending inputs to the ganglion. Intracellular recordings reveal that this gastro-pyloric interaction originates from the gastric MG and LG neurons of the gastric network, which inhibit the pyloric pacemaker ensemble. As a consequence, the pyloric PY neurons, which are inhibited by the pyloric dilator (PD) neurons of the pyloric pacemaker group, extend their activity during the time that PD neuron is held silent. Moreover, there is evidence for a pyloro-gastric interaction, apparently rectifying, from the pyloric pacemakers back to the gastric MG/LG neuron group.
Clemens, S., Massabuau, J. C., Meyrand, P., and Simmers, J. (1999). Changes in motor network expression related to moulting behaviour in lobster: Role of moult-induced deep hypoxia. Journal of Experimental Biology 202, 817-827.
The well known rhythmically active pyloric neural network in intact and freely behaving lobsters Homarus gammarus was monitored prior to and following ecdysis, Despite long-lasting hormonal and metabolic alterations associated with this process, spontaneous pyloric network activity remained largely unaltered until the last 12-48 h before exuviation. At this time, the most notable change was a progressive lengthening of pyloric cycle period, which eventually attained 500-600% of control values. It was only in the very last minutes before ecdysis that burst patterning became irregular and the otherwise strictly alternating motor sequence broke down. After the moult, coordinated rhythmicity was re-established within 10 min, Concomitant with these final changes in motor network expression at ecdysis was a drastic reduction in blood oxygen levels which led to a temporary near-anoxia, By imposing similarly deep hypoxic conditions both on intermoult animals and on the pyloric network in vitro, we mimicked to a large extent the moult-induced changes in pyloric network performance, Our data suggest that, despite major surrounding physiological perturbations, the pyloric network in vivo retains stable pattern-generating properties throughout much of the moulting process. Moreover, some of the most significant modifications in motor expression just prior to ecdysis can be related to a substantial reduction in oxygen levels in the blood.
Clement, R. E., Tosine, H. M., Taguchi, V., Musial, C. J., and Uthe, J. F. (1987). Investigation of American lobster, Homarus americanus, for the presence of chlorinated dibenzo-p-dioxins and dibenzofurans. Bull Environ Contam Toxicol 39, 1069-75.
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Cobb, J. S. (1997). Oceanic processes affecting lobster larvae: report from a workshop. Marine and Freshwater Research 48, 771-775.
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Cobb, J. S., Booth, J. D., and Clancy, M. (1997). Recruitment strategies in lobsters and crabs: a comparison. Marine and Freshwater Research 48, 797-806.
Early life-history characteristics that affect recruitment in spiny lobsters, clawed lobsters and crabs of the genus Cancer are reviewed. Spiny lobsters have many small eggs, a short period of parental care, and a long larval life that terminates in a swimming postlarva. Cancer species also have many small eggs, but have a longer period carrying eggs and a short larval life. Clawed lobsters have smaller clutches than the other two groups, long parental care and a short larval period. A cluster analysis on these and other characters in the 16 species considered shows that phylogeny dominates the clustering, because species of the same family group together. Within families, however, some possible environmental effects are seen. Spiny lobsters and Cancer crabs, with greater fecundity and presumably lower larval survival, may be predicted to have greater recruitment variability than clawed lobsters. The limited data available suggest that this is true.
Cockcroft, A. C. (1997). Biochemical composition as a growth predictor in male west- coast rock lobster (Jasus lalandii). Marine and Freshwater Research 48, 845-856.
The biochemical composition of the hepatopancreas and abdominal muscle tissue of adult male Jasus lalandii in two size classes was examined on a monthly and moult-cycle basis over four years to determine the accumulation and utilization of the major reserves in these tissues. The possibility of using this information to predict moult increment, defined as the increase in carapace length, was examined. Two study areas were selected to provide contrasting information on high and low growth rates, and the annual moult increments in these areas were determined from tag-and-recapture studies. The biochemical composition of abdominal muscle did not meet the prerequisites for a predictive index of growth. Hepatopancreas moisture content (lowest values measured during accumulation of reserves) showed a negative correlation with growth increment. Peak lipid content (as both percentage and absolute values) showed a positive correlation with measured moult increment. The relationship between percentage of lipid (both size classes combined) and moult increment was highly significant. Notwithstanding the limitations introduced by the small number of high-growth data points in this study, it appears that hepatopancreas lipid content can be used as a simple and robust predictive indicator of growth in adult male J. lalandii.
Cole, J. J., and Lang, F. (1980). Spontaneous and evoked postsynaptic potentials in an embryonic neuromuscular system of the lobster, Homarus americanus. J Neurobiol 11, 459-70.
The embryonic motor innervation to the deep extensor abdominal muscles was studied in lobster eggs in which reflex twitches and tail flips could be evoked by mechanical stimulation in early embryos. Recordings from impaled fibers during early and later stages of embryonic development revealed spontaneous depolarizing and hyperpolarizing potentials, suggesting the presence of excitatory and inhibitory axons. Stimulation of the extensor motor innervation produced a variety of EPSPs and IPSPs. The depolarizing responses included small and large EPSPs and nonovershooting spikes. Although moderate facilitation of the EPSP was sometimes observed, defacilitation was observed in the majority of fibers of all stages. Spiking could not be evoked by motor axon stimulation in embryos of early stages. These findings indicate that from the outset the deep abdominal extensor neuromuscular system of the lobster is phasic in its response to nerve stimulation and is functional as part of the tail flip reflex at least six months before hatching.
Combes, D., Simmers, J., and Moulins, M. (1997). Conditional dendritic oscillators in a lobster mechanoreceptor neurone. J Physiol (Lond) 499, 161-77.
1. Intra- and extracellular recordings were made from in vitro preparations of the lobster (Homarus gammarus) stomatogastric nervous system to study the nature and origin of pacemaker-like activity in a primary mechanoreceptor neurone, the anterior gastric receptor (AGR), whose two bilateral stretch-sensitive dendrites ramify in the tendon of powerstroke muscle GM1 of the gastric mill system. 2. Although the AGR is known to be autoactive, we report here that in 20% of our preparations, rather than autogenic tonic discharge, the receptor fired spontaneously in discrete bursts comprising three to ten action potentials and repeating at cycle frequencies of 0.5-2.5 Hz in the absence of mechanical stimulation. Intrasomatic recordings revealed that such rhythmic bursting was driven by slow oscillations in membrane potential, the frequency of which was voltage sensitive and dependent upon the level of stretch applied to the receptor terminals of the AGR. 3. Autoactive bursting of the AGR originated from an endogenous oscillatory mechanism in the sensory dendrites themselves, since (i) during both steady, repetitive firing and bursting, somatic and axonal impulses were always preceded 1:1 by dendritic action potentials, (ii) hyperpolarizing the AGR cell body to block triggering of axonal impulses revealed attenuated somatic spikes that continued to originate from the two peripheral dendrites, (iii) the timing of burst firing could be phase reset by brief electrical stimulation of either dendrite, and (iv) spontaneous bursting continued to be expressed by an AGR dendrite after physical isolation from the GM1 muscle and the stomatogastric nervous system. 4. Although a given AGR in vitro could switch spontaneously from dendritic bursting to tonic firing and vice versa, exogenous application of micromolar (or less) concentrations of the neuropeptide F1 (TNRNFLRFamide) to the dendritic membrane could rapidly and reversibly switch the receptor firing pattern from repetitive firing to the bursting mode. Exposure of the somatic and axonal membrane of the AGR to F1 was without effect, as were applications of other neuroactive substances such as serotonin, octopamine and proctolin. 5. We conclude that, as for many oscillatory neurones of the central nervous system, the intrinsic activity pattern of this peripheral sensory neurone may be dynamically conferred by extrinsic modulatory influences, presumably according to computational demands. Moreover, the ability of the AGR to behave as an endogenous burster imparts considerable integrative complexity since, in this activity mode, sensory coding not only occurs through the frequency modulation of on-going dendritic bursts but also via changes in the duration of individual bursts and their inherent spike frequencies.
Combes, D., Meyrand, P., and Simmers, J. (1999). Motor pattern specification by dual descending pathways to a lobster rhythm-generating network. Journal of Neuroscience 19, 3610-3619.
In the European lobster Homarus gammarus, rhythmic masticatory movements of the three foregut gastric mill teeth are generated by antagonistic sets of striated muscles that are driven by a neural network in the stomatogastric ganglion. In vitro, this circuit can spontaneously generate a single (type I) motor program, unlike in vivo in which gastric mill patterns with different phase relationships are found. By using paired intrasomatic recordings, all elements of the gastric mill network, which consists mainly of motoneurons, have been identified and their synaptic relationships established. The gastric mill circuit of Homarus is similar to that of other decapod crustaceans, although some differences in neuron number and synaptic connectivity were found. Moreover, specific members of the lobster network receive input from two identified interneurons, one excitatory and one inhibitory, that project from each rostral commissural ganglion. Integration of input from these projection elements is mediated by synaptic interactions within the gastric mill network itself. In arrhythmic preparations, direct phasic stimulation of the previously identified commissural gastric (CG) interneuron evokes gastric mill output similar to the type I pattern spontaneously expressed in vitro and in vivo. The newly identified gastric inhibitor interneuron makes inhibitory synapses onto a different subset of gastric mill neurons and, when activated with the CG neuron, drives gastric mill output similar to the type II pattern that is only observed in the intact animal. Thus, two distinct phenotypes of gastric mill network activity can be specified by the concerted actions of parallel input pathways and synaptic connectivity within a target central pattern generator.
Combes, D., Meyrand, P., and Simmers, J. (1999). Dynamic restructuring of a rhythmic motor program by a single mechanoreceptor neuron in lobster. Journal of Neuroscience 19, 3620-3628.
We have explored the synaptic and cellular mechanisms by which a single primary mechanosensory neuron, the anterior gastric receptor (AGR), reconfigures motor output of the gastric mill central pattern generator (CPG) in the stomatogastric nervous system (STNS) of the lobster Homarus gammarus. AGR is activated in vivo by contraction of the medial tooth protractor muscle gm1 and accesses the gastric CPG via excitation of two in- parallel interneurons, the excitatory commissural gastric (CG) and the inhibitory gastric inhibitor (GI). In the spontaneously active STNS in vitro, weak firing of AGR in time with gastric mill motoneurons (GM) reinforces an ongoing type gastric mill rhythm in which all gastric teeth power-stroke motoneurons are synchronously active. With strong AGR firing, these phase relationships switch abruptly to a type II pattern in which lateral and medial teeth power-stroke motoneurons fire in antiphase. Our results suggest that these bimodal actions on the gastric mill rhythm depend on the balance of firing of the CG and GI interneurons and that selection of the pathway resides in their different postsynaptic sensitivities to AGR. Whereas high intrinsic firing rates of the CG neuron ensure that the excitatory pathway predominates during low levels of sensory input, strong synaptic facilitation in the GI neuron favors the inhibitory pathway during high levels of receptor activity. Feedback from a single mechanosensory neuron is thus able, in an activity-dependent manner, to specify different motor programs from a single central pattern-generating network.
Cooke, I. M., and Hartline, D. K. (1975). Neurohormonal alteration of integrative properties of the cardiac ganglion of the lobster Homarus americanus. J Exp Biol 63, 33-52.
The spontaneous burst discharges of isolated lobster (Homarus americanus) cardiac ganglia were recorded with a spaced array of electrodes. Small regions (less than 1 mm) of the ganglion were exposed to the cardioexcitor neurohormone in extracts of pericardial organs (XPO) or to 10(-5) M 5-hydroxytryptamine (5HT). All axons were excited (increased mean firing frequency, f) by both substances, but only by applications in the region between the soma (but excluding it) and proximal site of impulse initiation. Units not so exposed changed their f relatively little despite f increases of as much as threefold in exposed units and changes in burst rate and overall length. Regularity and grouping of all impulse activity into bursts was never disturbed. 5HT increases burst rate at any point of application. The increases are larger if small cells are affected than if only large cells are exposed. Burst length decreases except when the pacemaker is affected. In contrast, XPO affects neither burst rate or length unless small cells are affected. Length is increased if non-pacemaker small cells are affected; both rate and length increase if the pacemaker is affected. The pacemaker usually exhibits an f of intermediate value. Rate changes are not simply related to its f. A small cell can "burst" in the absence of impulses from any other cells. XPO may enhance endogenous "driver potentials," while 5HT may excite by depolarizing at limited sites.
Cooper, R. A., and Uzmann, J. R. (1971). Migrations and growth of deep-sea lobsters, Homarus americanus. Science 171, 288-90.
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Cornick, J. W., and Stewart, J. E. (1973). Partial characterization of a natural agglutinin in the hemolymph of the lobster, Homarus americanus. J Invertebr Pathol 21, 255-62.
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Corotto, F. S., Bonenberger, D. M., Bounkeo, J. M., and Dukas, C. C. (1999). Antennule ablation, sex discrimination, and mating behavior in the crayfish Procambarus clarkii. Journal of Crustacean Biology 19, 708-712.
In order for the crayfish Procambarus clarkii to mate, each animal involved must identify the sex of the other. Crayfish are able to use chemoreception, mediated by the first antennae (antennules), as well as vision in sex identification. The relative importance of these two senses is not known; most work has centered on the use of the antennules. To assess the importance of antennules we studied mating in control pairs, in pairs where the females lacked antennules, in pairs where males lacked antennules, and in pairs where both lacked antennules. Ablation of antennules did not significantly affect the likelihood of mating or the delay before mating began. These findings demonstrate that P. clarkii can readily identify the sex of conspecifics without the use of their antennules. If the ability to identify sex had been impaired, one would expect mating to be less likely or to follow an unusually long delay. In addition, antennule ablation did not significantly affect the duration of mating. This stands in contrast to findings in the green crab Carcinus maenas, where the ablation of antennules in males leads to the substitution of multiple short matings for single long, continuous matings. It is concluded that P. clarkii can readily determine the sex of conspecifics without the use of the antennules and that the loss of antennules has no obvious effect on mating behavior.
Costello, W. J., and Govind, C. K. (1984). Contractile proteins of fast and slow fibers during differentiation of lobster claw muscle. Dev Biol 104, 434-40.
Contractile protein populations were determined, using gel electrophoresis, during development of the claw closer muscles of the lobster Homarus americanus. In the adult the paired claw closer muscles are asymmetric, consisting of a crusher muscle with all slow fibers and a cutter muscle with a majority of fast and a few slow fibers. The electrophoretic banding pattern of these adult fast and slow fibers shows a similarity in the major proteins including myosin, actin, and tropomyosin which are common to both fiber types. Paramyosin is slightly heavier in fast fibers than in slow. However, fast fibers have three proteins and slow fibers have four proteins which are unique to themselves. Several of these unique proteins belong to the regulatory troponin complexes. In juvenile 4th stage lobster, where the paired closer muscles are undifferentiated, the banding pattern reveals the presence of proteins common to both fiber types including myosin, actin, and tropomysin but the conspicuous absence of all unique fast fiber proteins as well as one unique slow fiber protein. By the juvenile 10th stage most of these unique proteins are present except for one unique slow fiber protein. Thus lobster fast and slow fiber differentiation entails coordinate gene activation to add unique contractile proteins.
Costello, W. J., Hill, R. H., and Lang, F. (1984). Firing patterns of closer motoneurons during reflex activity in the dimorphic claws of the lobster Homarus americanus. J Exp Zool 231, 167-75.
The in vivo firing patterns of the fast closer excitor (FCE) and slow closer excitor (SCE) motoneurons to the dimorphic claws of the lobster Homarus americanus were analyzed during reflex closure activity by identifying postsynaptic potentials in muscle fibers with known motor innervation. Three types of claw activity were observed: slow closure, rapid closure, and maintained closure. Slow closure and rapid closure in both claws were mediated by SCE and FCE, respectively. In the cutter, maintained closure was mediated only by SCE; in the crusher, both FCE and SCE could maintain closure. The homologous SCEs displayed no significant differences in activity; in both claws, they fired at medium-to-high frequency. The homologous FCEs did display different spike frequencies during claw closure. The crusher FCE fired at high frequencies; the cutter FCE fired at much lower frequencies. Such in vivo differences in axon activity between homologous FCEs are correlated with claw dimorphism and with the population of muscle fiber types.
Cote, I. M., and Jelnikar, E. (1999). Predator-induced clumping behaviour in mussels (Mytilus edulis Linnaeus). Journal of Experimental Marine Biology and Ecology 235, 201-211.
This study examined the aggregation behaviour of blue mussels, Mytilus edulis, under threat of predation by European lobster, Homarus gammarus Linnaeus. Risk of predation was simulated using water in which a hungry lobster had been for 24 h, and mussels were initially set in experimental containers either near (0.5 body length apart) or far (1.5 body length apart) from each other. We found that mussels exposed to lobster effluent formed more clumps, more rapidly than mussels in control conditions. The initial distance separating the mussels had no effect on their aggregation tendencies. Overall, a greater proportion of mussels were aggregated in the lobster treatment at the end of the 22-h experiment. This was not simply the result of increased locomotion. Although mussels in lobster effluent did exhibit greater crawling speed in the first hour of the experiment, mussels initially set far apart also showed enhanced locomotion in both lobster and control treatments. Yet, of the mussels initially far from each other, those in lobster effluent formed clumps on average 5 h sooner than mussels in control water. This suggests that chemotaxis may be involved. Although mussels do aggregate under risk of predation in the laboratory, it is not yet known whether predation plays a significant role in the formation of natural mussel beds. (C) 1999 Elsevier Science B.V. All rights reserved.
Cotton, J. L., and Mykles, D. L. (1993). Cloning of a crustacean myosin heavy chain isoform: exclusive expression in fast muscle. J Exp Zool 267, 578-86.
A clone of a fast isoform of myosin heavy chain (HC) gene was isolated from a cDNA1 expression library made from mRNA purified from the deep abdominal flexor muscle of the lobster, Homarus americanus. The cDNA (1.5 kb) contained the 3' untranslated region (UTR) and the coding sequence for the last 413 amino acid residues of the carboxyl terminus of the polypeptide. The deduced amino acid sequence showed high homology with that of myosin HCs from Drosophila (73% identity), nematode (57% identity), and vertebrates (49% identities). Hydropathy plots showed a 28-amino acid periodicity that is consistent with the alpha-helical coiled coil structure of the rod region of native myosin. Northern blot analysis and in situ hybridization showed that the fast myosin HC isoform was expressed only in fast fibers; the probes did not hybridize to mRNA from slow fibers. The message consisted of a single transcript of 6.6 kb. The intracellular localization of the fast myosin mRNA was not uniform. The mRNA was largely confined to the intermyofibrillar spaces and to the subsarcolemmal cytoplasm of the fiber periphery and large infoldings of the cell membrane. Within these regions the mRNA was concentrated in the cytoplasm immediately surrounding the nuclei. This constitutes the first report of the cloning and expression of a myosin HC gene from a crustacean species.
Cournil, I., Meyrand, P., and Moulins, M. (1990). Identification of all GABA-immunoreactive neurons projecting to the lobster stomatogastric ganglion. J Neurocytol 19, 478-93.
The stomatogastric ganglion of lobsters (Homarus or Jasus) contains a large number of gamma-aminobutyric acid-immunoreactive processes originating from ten fibres in the single input nerve, the stomatogastric nerve. The cell bodies and axonal pathways of these ten fibres have been identified using gamma-aminobutyric acid immunohistochemistry in combination with Lucifer Yellow staining (double labelling) and nickel chloride backfilling (selective gamma- aminobutyric acid immunoinhibition). It is shown that eight gamma- aminobutyric acid-immunoreactive neurons project to the stomatogastric ganglion: gamma-aminobutyric acid neurons 1 and 2, found posterior to the oesophageal ganglion, entering the stomatogastric nerve via the oesophageal nerve as well as sending an axonal branch into each superior oesophageal nerve; gamma-aminobutyric acid neurons 3 and 4, found anterior to the oesophageal ganglion, each sending an axonal branch into each inferior oesophageal nerve to reach the stomatogastric nerve via the commissural ganglion and the superior oesophageal nerve; and gamma-aminobutyric acid neurons 5 and 6, found in each commissural ganglion, projecting into the stomatogastric nerve via the inferior oesophageal nerve, the oesophageal ganglion and the oesophageal nerve. These gamma-aminobutyric acid-immunoreactive neurons were also characterized by electrophysiological methods coupled with Lucifer Yellow labelling, and their picrotoxin-sensitive effects on several stomatogastric ganglion neurons were demonstrated. The present results provide a firm basis for further studies concerning the physiological significance of one class of neurochemically-defined input neurons to stomatogastric ganglion networks.
Cournil, I., Helluy, S. M., and Beltz, B. S. (1994). Dopamine in the lobster Homarus gammarus. I. Comparative analysis of dopamine and tyrosine hydroxylase immunoreactivities in the nervous system of the juvenile. J Comp Neurol 344, 455-69.
As a catecholamine, dopamine belongs to a class of molecules that have multiple transmitter and hormonal functions in vertebrate and invertebrate nervous systems. However, in the lobster, where many central neurons have been identified and the peripheral innervation pattern is well known, the distribution of dopamine-containing neurons has not been examined in detail. Therefore, immunocytochemical methods were used to identify neurons likely to contain dopamine and tyrosine hydroxylase in the central nervous system of the juvenile lobster Homarus gammarus. Approximately 100 neuronal somata stain for the catecholamine and/or its synthetic enzyme in the brain and ventral nerve cord. The systems of neurons labeled with dopamine and tyrosine hydroxylase antibodies have the following characteristics: 1) the two systems are nearly identical; 2) every segmental ganglion contains at least one pair of labeled neurons; 3) the positions and numbers of cell bodies labeled with each antiserum are similar in the various segmental ganglia; 4) six labeled neurons are anatomically identified; two interneurons from the brain project within the ventral cord to reach the last abdominal ganglion, two neurons from the commissural ganglia are presumably neurosecretory neurons, and two anterior unpaired medial abdominal neurons project to the hindgut muscles; and 5) no cell bodies are labeled in the stomatogastric ganglion, but fibers and terminals in the neuropil are stained. The remarkably small numbers of labeled neurons and the presence of very large labeled somata with far-reaching projections are distinctive features consistent with other modulatory aminergic systems in both vertebrates and invertebrates.
Cournil, I., Casasnovas, B., Helluy, S. M., and Beltz, B. S. (1995). Dopamine in the lobster Homarus gammarus: II. Dopamine-immunoreactive neurons and development of the nervous system. J Comp Neurol 362, 1-16.
Dopamine-immunoreactive neurons were revealed in lobster embryos, larvae, and postlarvae, and staining patterns were compared to neuronal labeling in the juvenile lobster nervous system (Cournil et al. [1994] J. Comp. Neurol. 344:455-469). Dopamine immunoreactivity is first detected by midembryonic life in 35-40 neuronal somata located anteriorly in brain and subesophageal ganglion. When the lobsters assume a benthic life during the first postlarval stage, an average of 58 cell bodies are labeled. The acquisition of dopamine in lobster neurons is a protracted event spanning embryonic, larval, and postlarval life and finally reaching the full complement of roughly 100 neurons in juvenile stages. Some of the dopaminergic neurons previously identified in the mature nervous system, such as the paired Br cells, L cells, and mandibular cells, are labeled in embryos and persist throughout development. In contrast, other neurons stain transiently for dopamine during the developmental period, but, by the adult stage, these neurons are no longer immunoreactive. Such transiently labeled neurons project to the foregut, the thoracic dorsal muscles, the neurohormonal pericardial plexus, and the pericardial pouches. It is proposed that these neurons are alive and functioning in adult lobster but that dopamine levels have been abolished, providing that neurotransmitter status is a dynamic, changing process.
Cowan, D. F. (1999). Method for assessing relative abundance, size distribution, and growth of recently settled and early juvenile lobsters (Homarus americanus) in the lower intertidal, zone. Journal of Crustacean Biology 19, 738-751.
The purpose of this study was to establish a method for repeated, year-round sampling of the abundance of young-of-the- year and juvenile lobsters, Homarus americanus, where they can be found intertidally. The primary advantage of the intertidal lobster monitoring program is the ability to overcome limitations pursuant to subtidal sampling techniques through increased temporal and spatial resolution of data collected, using sampling methods possible at low tide. Lobsters were sampled monthly throughout the years 1993-1997 by overturning rocks in one-m(2) quadrats placed along fixed transects running parallel to the water's edge 0.2-0.4 m below mean low water (MLW). Individuals were tagged using binary-coded microwire tags. Two distinct size classes of lobsters, the smaller measuring 3-15 mm in carapace length (CL), the larger measuring 16-40 mm CL, were found consistently. Monthly mean densities ranged from 0-8.6 individuals per m(2) at 0.4 m below MLW. These densities are comparable to published reports of similar- sized lobsters Sampled at depths of 5 m below MLW. A seasonal pattern of abundance was observed, with the highest average densities recorded in May-November. Lower abundance in December-April was most likely due to seasonal migrations of individuals of the larger size class. Preliminary results indicate that areas of the lower intertidal zone serve as nursery grounds where postlarval lobsters settle and grow for several years. The assessment method developed in this study is being used to establish a time series that may be useful in developing and testing predictive models of annual yields and recruitment to the lobster fishery. The close proximity of intertidal lobster nurseries to the terrestrial zone indicates serious implications for fisheries management and issues of habitat protection in the shoreland zone. Further investigations are needed to yield a more complete picture of the full geographical extent of use of the intertidal zone as a nursery area for lobsters.
Cribb, A. E., Despres, B., and Cawthorn, R. J. (1999). Tetrazolium-based cytotoxicity assay to determine anti- protozoal activity against the scuticociliate Anophryoides haemophila. Diseases of Aquatic Organisms 35, 213-219.
Anophryoides haemophila is a ciliated protozoan that causes 'bumper car' disease in American lobster Homarus americanus. Currently, there are no effective pharmaceuticals approved for use to treat the disease, which can be a significant source of mortality in lobster holding facilities. We have modified a tetrazolium-based cytotoxicity assay to determine the anti- protozoal activity of compounds towards A. haemophila. To obtain reproducible results, A. haemophila maintained in continuous culture were preferable to freshly isolated A. haemophila. It was also found that the ciliates must be replicating to produce reproducible results. Maximal anti- protozoal activity was evident after a 24 h incubation period. Oxytetracycline was found to be relatively inactive, while high concentrations (1 mM) of formaldehyde and sulphaquinoxaline were required to produce 50 % cytotoxicity. In contrast, 100 mu M lasalocid produced 92 +/- 4 % and 100 mu M pyrimethamine produced 84 +/- 6.5 % cytotoxicity after 24 h. This objective assay provides a rapid means of screening compounds to identify those with potential in vivo activity against Anophryoides haemophila.
Cromarty, S. I., and Kass-Simon, G. (1998). Differential effects of a molting hormone, 20-hydroxyecdysone, on the neuromuscular junctions of the claw opener and abdominal flexor muscles of the American lobster. Comparative Biochemistry and Physiology a-Molecular and Integrative Physiology 120, 289-300.
Intracellular recordings at the neuromuscular junction of the dactyl opener muscle and the abdominal phasic flexor muscle of intermolt lobsters were made in the presence and absence of the steroid hormone, 20-hydroxyecdysone (20-HE). Evoked excitatory junctional potentials (EJPs) were recorded from both muscles; spontaneous miniature excitatory junctional potentials (MEJPs) were recorded from the claw. In the opener muscle, 20-HE caused an increase in EJP amplitudes and MEJP frequency. In the abdomen 20-HE caused EJP amplitudes to become significantly smaller than controls. These results are consistent with changes in the relative activity of the two muscles over the molt cycle. In premolt lobsters where the titers of 20-HE are highest, there is an increased tendency towards aggressive behaviors (which include the meral spread) and a corresponding reduction of escape swimming. The results also support our earlier findings that one or more molt-related blood-borne factors can modulate peripheral synaptic transmission. (C) 1998 Elsevier Science Inc. All rights reserved.
Cromarty, S. I., Mello, J., and Kass-Simon, G. (1998). Comparative analysis of escape behavior in male, and gravid and non-gravid, female lobsters. Biological Bulletin 194, 63-71.
Few studies exist in which the parameters of a single behavior have been quantitatively compared for male and female lobsters. Here, we have examined the effects of sex and gravidity on the parameters of the escape behavior of the American lobster, Homarus americanus, elicited by a visual threat. Both non- gravid females and male lobsters readily tail-flipped in response to the stimulus, but gravid females failed, with one exception, to initiate a swim, even when stimulus strength was increased. Although the total distance swum by males and nongravid females was not statistically different, males covered more ground in the initial power swim and during the subsequent swims than did non-gravid females. Males swam for a longer time, performing more tailflips, than females. Relative to their length and weight, males swam a greater distance at each stroke during the initial power swim and the subsequent swims, although, females might have compensated by swimming at a higher frequency. There were no significant differences in swimming velocity or acceleration, nor in the calculated force or work performed by the two sex classes (male and non-gravid females). Therefore, apart from egg-bearing, which severely inhibits the escape response, it remains to be seen whether the subtle physiological and anatomical sexual dimorphism that produces longer and more swim strokes in males but higher frequency tailflips in females results in the same chances of survival for the sexes.
Cromarty, S. I., Mello, J., and Kass-Simon, G. (1999). Time in residence affects escape and agonistic behavior in adult male American lobsters. Biological Bulletin 196, 105-112.
Acquisition and retention of a shelter by a lobster are two of the variables that play a role in lobster agonistic interactions. Since shelter procurement and retention are important for lobster survival, behaviors related to this activity frequently outrank other daily behaviors (e.g., searching for food). Here, we examine the effects of time in residence on the parameters of the escape response of the American lobster, Homarus americanus. Adult male intermolt lobsters (Stage C-4) were placed in an experimental tank for three different time periods (one hour, 24 hours, and 48 hours). The probability of eliciting an escape response was inversely related to the time spent in the tank. Eighty percent of the animals in residence for 1 h tailflipped in response to a threat, whereas only 14% of the animals in residence for 48 h tailflipped. There were also significant changes in some of the parameters of the escape response among animals in residence for 24 h compared to those in residence for 1 h. The number of tailflips and the distance traveled were reduced, although frequency, velocity, acceleration, force, and work factors were not significantly different. Furthermore, with increased time in residence, lobsters switched from an avoidance or escape- prone behavior to an aggressive-prone behavior. Most of the animals in residence for 48 h approached and attacked a threat- stimulus rather than fleeing from it. On an empirically defined "index of aggressiveness," in which various behaviors were numerically ranked from least aggressive (0) to most aggressive (6), animals residing in the tank for 1 h had an average index value of 0.1 compared to a value of 5.0 for animals in residence for 48 h. These findings are consonant with the suggestion that lobsters that have occupied a given space for an extended period of time take possession of the site and defend it instead of fleeing when threatened with a threat- inducing stimulus; it supports the idea that shelter retention increases aggressiveness and diminishes avoidance behaviors.
Crossin, G. T., Al-Ayoub, S. A., Jury, S. H., Howell, W. H., and Watson, W. H. (1998). Behavioral thermoregulation in the American lobster Homarus americanus. Journal of Experimental Biology 201, 365-374.
It is generally accepted that water temperature has a strong influence on the behavior of the American lobster Homarus americanus. However, there is surprisingly little behavioral evidence to support this view, To characterize the behavioral responses of lobsters to thermal gradients, three different experiments were conducted, In the first, 40 lobsters acclimated to summer water temperatures (summer-acclimated, 15.5+/-0.2 degrees C, mean +/- S.E.M.) were placed individually in an experimental shelter, and the temperature in the shelter was gradually raised until the lobster moved out, Lobsters avoided water warmer than 23.5+/-0.4 degrees C, which was an increase of 8.0+/-0.4 degrees C from ambient summer temperatures, When this experiment was repeated with lobsters acclimated to winter temperatures (winter-acclimated, 4.3+/-0.1 degrees C), the lobsters (N=30) did not find temperature increases of the same magnitude (Delta T=8.0+/-0.4 degrees C) aversive, The second experiment was designed to allow individual summer-acclimated lobsters (N=22) to select one of five shelters, ranging in temperature from 8.5 to 25.5 degrees C, After 24 h, 68% of the lobsters occupied the 12.5 degrees C shelter, which was slightly above the ambient temperature (approximately 11 degrees C), In a similar experiment, winteracclimated lobsters (N=30) were given a choice between two shelters, one at ambient temperature (4.6+/-0.2 degrees C) and one at a higher temperature (9.7+/-0.3 degrees C). Winter- acclimated lobsters showed a strong preference (90%) for the heated shelter, In the final experiment, summer-acclimated lobsters (N=9) were allowed to move freely in a tank having a thermal gradient of approximately 10 degrees C from one end to the other, Lobsters preferred a thermal niche of 16.5+/-0.4 degrees C and avoided water that was warmer than 19 degrees C or colder than 13 degrees C, When standardized for acclimation temperature, lobsters preferred water 1.2+/-0.4 degrees C above their previous ambient temperature, Collectively, the results of these studies indicate that lobsters are capable of sensing water temperature and use this information to thermoregulate behaviorally, The implications of these findings for lobster behavior and distribution in their natural habitat are discussed.
Dando, M. R., and Laverack, M. S. (1968). A mandibular proprioceptor in the lobster, Homarus vulgaris. Experientia 24, 931-2.
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Darin De Lorenzo, A. J., Brzin, M., and Dettbarn, W. D. (1968). Fine structure and organization of nerve fibers and giant axons in Homarus americanus. J Ultrastruct Res 24, 367-84.
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Davidson, G. W., Wilkens, J. L., and Lovell, P. (1998). Neural control of the lateral abdominal arterial valves in the lobster Homarus americanus. Biological Bulletin 194, 72-82.
A dorsal abdominal artery in Homarus americanus runs the length of the abdomen, giving rise to one pair of large lateral arteries in each segment. These lateral arteries supply hemolymph to the abdominal muscles and the swimmerets. In addition, many small vessels leave the dorsal abdominal artery ventrolaterally to supply the gut and gonads. Bicuspid muscular valves are located at the junction of each segmental lateral artery with the dorsal abdominal artery, but not at the origin of the gut vessels. Nerves originating from the ventral abdominal ganglia travel along the lateral arteries to innervate the valves, providing both inhibitory and excitatory inputs. Inhibitory input produces hyperpolarizing inhibitory junctional potentials that relax the valve muscles, and in intact in situ perfused arteries causes increases in outflow from the affected lateral artery. Excitatory input produces depolarizing excitatory junctional potentials that close the valves and reduce perfusate outflow. The valve nerves also branch to innervate valves up to two segments anterior and one segment posterior. Application of exogenous gamma-aminobutyric acid hyperpolarizes valve muscle fibers. This and the hyperpolarizing effect of valve nerve stimulation are reversibly abolished by the application of picrotoxin (10(-5) M). Acetylcholine (10(-5) M), but not glutamate, causes depolarization and contraction of valves. The role of the valves in controlling the distribution of hemolymph flow is discussed.
Davison, I. G., Wright, G. M., and DeMont, M. E. (1995). The structure and physical properties of invertebrate and primitive vertebrate arteries. J Exp Biol 198, 2185-96.
Light and electron microscopy and in vitro inflation experiments were conducted on the aortae of three different invertebrate species: the lobster Homarus americanus, the horseshoe crab Limulus polyphemus and the whelk Busycon contrarium. Inflation experiments were also performed on the aortae of two species of primitive vertebrates, the sea lamprey Petromyzon marinus and the Atlantic hagfish Myxine glutinosa. The inflation experiments demonstrated similar overall biomechanical properties in each case, despite the existence of differences in tissue structure. The vessels were compliant at low strains, but demonstrated nonlinear elasticity, increasing in stiffness as strains increased; this property could act as protection against artery wall rupture. The vessels of the lamprey, hagfish and lobster are capable of acting as fairly efficient elastic reservoirs and of smoothing blood flow during circulation as they had low hysteresis values (13-18%). The aortae of the horseshoe crab and whelk, if performing this function, have much higher energy losses, up to more than 30% per cycle. The microscopy studies of the aortae of the lobster, horseshoe crab and whelk revealed tissue structures which differ widely from each other as well as from the structures of the lamprey and hagfish. None of these arteries contained elastin, but all contained fibrillar material which differed in appearance, size and arrangement between species. These materials were conjectured to contribute to the elastic properties of the tissue.
de Kleijn, D. P., Coenen, T., Laverdure, A. M., Tensen, C. P., and Van Herp, F. (1992). Localization of messenger RNAs encoding crustacean hyperglycemic hormone and gonad inhibiting hormone in the X-organ sinus gland complex of the lobster Homarus americanus. Neuroscience 51, 121-8.
The localization of messenger RNAs encoding the crustacean hyperglycemic hormone, involved in regulation of carbohydrate metabolism and the gonad inhibiting hormone, which inhibits vitellogenesis, was studied in the eyestalk of the lobster Homarus americanus using complementary RNA probes for in situ hybridization. For the detection of gonad inhibiting hormone messenger RNA, we cloned and sequenced a partial complementary DNA encoding lobster gonad inhibiting hormone and for crustacean hyperglycemic hormone messenger RNA detection an available complementary DNA was used. This approach reveals that there is a frequent but inconsistent cellular co- localization of the two neurohormones. Furthermore, our data show that male lobsters contain an equal number of neuroendocrine gonad inhibiting hormone cells as female lobsters. An additional study, involving the use of in situ hybridization in combination with immunocytochemistry, shows that the synthetic activity of the crustacean hyperglycemic hormone- and gonad inhibiting hormone- producing cells can be followed at the messenger RNA as well as the protein level. This reveals that when strong immunostaining is present, the messenger RNA staining is usually weak or absent and vice versa. In conclusion, the presence of cells, containing only gonad inhibiting hormone messenger RNA or only crustacean hyperglycemic hormone messenger RNA, indicates that lobster crustacean hyperglycemic hormone and gonad inhibiting hormone originate from two different precursors. Co-localization of the two neurohormone messenger RNAs confirms the co- localization at the peptidergic level found by immunocytochemistry and thus these findings were not due to cross-reactions between the two antisera.(ABSTRACT TRUNCATED AT 250 WORDS).
de Kleijn, D. P., Sleutels, F. J., Martens, G. J., and Van Herp, F. (1994). Cloning and expression of mRNA encoding prepro-gonad-inhibiting hormone (GIH) in the lobster Homarus americanus. FEBS Lett 353, 255-8.
The gonad-inhibiting hormone (GIH) is produced in the eyestalk X-organ sinus gland complex of male and female lobsters, and plays a prominent role in the regulation of reproduction, e.g. inhibition of vitellogenesis in female animals. To study this neurohormone at the mRNA level, we cloned and sequenced a cDNA which encodes GIH in the lobster Homarus americanus. The structure of preproGIH consists of a signal peptide and the GIH peptide itself. A comparative analysis revealed that lobster GIH, together with crab molt-inhibiting hormone, belongs to a separate group of the crustacean hyperglycemic hormone (CHH) peptide family which seems to be unique for crustaceans. Expression studies showed that GIH mRNA is expressed in the eyestalk, indicating that the neuroendocrine center in this optic structure is the only source of GIH. As this center modulates the other (neuro)endocrine organs in crustaceans, it is postulated that GIH regulates production and release of hormones involved in reproduction/molting processes.
de Kleijn, D. P., de Leeuw, E. P., van den Berg, M. C., Martens, G. J., and van Herp, F. (1995). Cloning and expression of two mRNAs encoding structurally different crustacean hyperglycemic hormone precursors in the lobster Homarus americanus. Biochim Biophys Acta 1260, 62-6.
The crustacean hyperglycemic hormone (CHH) of the X-organ sinus gland complex is a multifunctional neurohormone primarily involved in the regulation of blood sugar levels. HPLC analysis of lobster sinus glands revealed two CHH-immunoreactive groups, each consisting of two isoforms with identical amino acid sequences and molecular weights. In order to obtain more information concerning the number and sequences of preproCHHs, and to study their expression, we isolated two full-length cDNAs encoding two different CHH preprohormones. Both preprohormone structures consist of a signal peptide, a CHH-precursor-related peptide and a highly-conserved CHH peptide. Expression studies revealed that the X-organ is not the only source of CHH mRNA because the ventral nerve system also expresses this mRNA. Based on these findings and earlier studies on the effect of eyestalk ablation, implantation of thoracic/abdominal ganglia as well as the multifunctionality of CHH, we postulate that CHH, present in the ventral nerve system is a good candidate for a supplementary role in the control of reproduction and molting.
De Kleijn, D. P. V., and Van Herp, F. (1998). Involvement of the hyperglycemic neurohormone family in the control of reproduction in decapod crustaceans. Invertebrate Reproduction & Development 33, 263-272.
In the last few years, (bio)chemical and molecular biological studies have shown that several members of the hyperglycemic hormone family are present in different molecular forms. In vivo and in vitro bioassays revealed that some of these isoforms also play a role in the control of reproduction in decapod crustaceans. This communication gives a review of the cytological aspects of the eyestalk X-organ sinus gland complex, responsible for the synthesis, storage and release of these neuropeptides, and the molecular and functional aspects of those members involved in the control of reproduction. Finally, the role of the hyperglycemic hormone family in the regulation of reproduction in the female lobster is described as an example of the (possible) interactions of the members of the hyperglycemic hormone family with other (neuro)endocrine factors in the reproductive process of crustaceans.
de Kleijn, D. P. V., Janssen, K. P. C., Waddy, S. L., Hegeman, R., Lai, W. Y., Martens, G. J. M., and Van Herp, F. (1998). Expression of the crustacean hyperglycaemic hormones and the gonad-inhibiting hormone during the reproductive cycle of the female American lobster Homarus americanus. Journal of Endocrinology 156, 291-298.
Crustacean reproduction is regulated by a complex chain of hormonal interactions in which the crustacean hyperglycaemic hormones A and B (CHH-A and CHH-B) and the gonad-inhibiting hormone (GIH) play a primary role. These neurohormones are produced in the same neuroendocrine cells of the X-organ sinus gland complex, situated in the eyestalks of the American lobster, Homanus americanus. In order to obtain more information on the synthesis, storage, release and function of these three neuropeptides during the reproductive cycle, we studied the levels of their mRNAs in the X-organ, their peptide storage in the sinus gland and their concentration in the haemolymph at different stages of the female reproductive cycle. A high CHH-A mRNA level was found only in the previtellogenic stage, while elevated mRNA levels were determined for CHH-B in the mature as well as the previtellogenic stage. High CHH storage levels in the sinus gland were found during previtellogenesis. The total amount of CHH (CHH-A plus -B) in the haemolymph was significantly higher during maturation. A low level of GIH mRNA in the X-organ and a low amount of the GIH I isoform in the sinus gland were found only in the immature stage. In contrast, GIH haemolymph levels were high during the immature and previtellogenic stages. We conclude that CHH-A and -B are involved in triggering the onset of vitellogenesis and that CHH-B in particular is responsible for stimulating oocyte maturation before spawning, while GIH prevents the start of vitellogenesis in the ovary. Moreover, our results show that the balance between the haemolymph levels of the CHHs and GIH may tune the synchronization of reproduction and molting during the biannual reproductive cycle of the American lobster.
De Menezes, M. A., Racco, A., and Penna, T. J. P. (1998). Strategies of reproduction and longevity. International Journal of Modern Physics C 9, 787-791.
In this work we try to verify whether the increased lifespan of trees and some lobsters, like Homarus, whose fertility increases with advancing age, can be explained by the mutation accumulation theory of biological ageing. Computer simulations of the Penna model seems to support this hypothesis, showing that it is a robust strategy of reproduction.
Debuire, B., Han, K. K., Dautrevaux, M., and Biserte, G. (1974). [Amino acid sequences of a peptide obtained by cyanogen bromide chemical fractionation of lobster (Homarus vulgaris) arginine-kinase]. C R Acad Sci Hebd Seances Acad Sci D 279, 101-4.
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Debuire, B., Han, K. K., Dautrevaux, M., and Biserte, G. (1975). Isolation and characterization of the cyanogen bromide fragments of lobster arginine kinase (homarus vulgaris). Int J Pept Protein Res 7, 69-80.
Arginine kinase was aminoethylated in order to block the five free thiol groups on the native enzyme, and then submitted to BrCN cleavage. The BrCN resulting peptides were soluble in propionic acid (10 percent) and subsequently submitted to gel-filtration. The large polypeptide subfractions were citraconylated and resubmitted to differnt gelchromatographies, whereas the short peptide subfractions were submitted to preparative paper electrochromatographies. Eight peptides of 2, 11, 17, 25, 61, 82, 86 and 132 amino acid residues were isolated, one of which is the overlapping of two peptides. The amino acid composition and the end group of all the isolated peptides were established. The short peptides (2, 11 and 17 residues) were sequenced. All peptides possess homoserine at C-terminal position because one methionyl residue is situated at the C-terminal position in the native protein. The polypeptide with 132 residues possessed N-acetylated residue at N-terminal position: therefore this polypeptide is located at the N-terminal position in the protein. The sum and account of each amino acid of the seven isolated peptides were compared to those of the intact protein: the sum of the seven peptides is 331 amino acid residues, whereas the whole protein contains 342 residues. The molecular weight of arginine kinase is revised and calculated on the basis of the present results (37, 687).
Debuire, B., Han, K. K., Dautrevaux, M., Biserte, G., Regnouf, F., and Kassab, R. (1977). Amino acid sequence of a cyanogen bromide fragment containing the two tryptophanyl residues of lobster arginine kinase (Homarus vulgaris). J Biochem (Tokyo) 81, 611-9.
Lobster arginine kinase [EC 2.7.3.3] contains 2 tryptophanyl residues and 9 methionyl residues. The whole carboxymethylated protein was first subjected to CNBr cleavage and the resulting fragments were isolated by gel filtration and other experimental approaches. One fragment, CB5, which contains 60 residues including the two tryptophanyl residues and two of the five cysteinyl residues of the protein, was characterized and the results are reported inthis paper. The overall strategy for the establishment of the complete sequence of this fragment was based on the use of three types of peptides: (a) whole cyanogen bromide peptide CB5 which was partially characterized by automatic Edman degradation using a sequencer: 42 steps were performed out of 60 residues, (b) tryptic peptides of CB5, (c) peptides formed by cleavage of S- carboxymethylated arginine kinase (whole protein) at the two tryptophanyl residues with BNPS-skatole. The complete amino acid sequence of the CNBr polypeptide (CB5) which contains the two tryptophanyl residues of the whole protein was established.
Debuse, V. J., Addison, J. T., and Reynolds, J. D. (1999). The effects of sex ratio on sexual competition in the European lobster. Animal Behaviour 58, 973-981.
During the breeding season an individual's access to mates may be affected by operational sex ratios, causing strong variation in mating success. We manipulated adult sex ratios of the European lobster, Homarus gammarus, to test the predictions of models that relate sexual competition to (1) the sex ratio, (2) the time that an individual is not available to mate and (3) 'collateral investment', whereby two males contribute to a single clutch. The model predictions proved to be relatively insensitive to collateral investment Male-male competition predominated in the male-biased but not in the female-biased sex ratio. This matches the predictions of one model that incorporates an extended period of female receptivity because the time that a male was unavailable to mate was small compared to the time spent by females in cohabitation and parental care. Although females increased their competitiveness when males were in the minority, male competition remained high. The insensitivity of male-male competition to sex ratios may be due to an upper limit to the costs that males can afford when there is a serious risk of injury, preventing males from increasing their aggression when females are in short supply. (C) 1999 The Association for the Study of Animal Behaviour.
Decker, H., Richey, B., Lawson, R. C., and Gill, S. J. (1983). Thin-layer fluorescence cell for ligand binding studies. Anal Biochem 135, 363-8.
A high precision method for measuring the binding of gaseous ligands to proteins is presented. Front face fluorescence techniques are utilized with a special thin-layer cell in order to monitor the change in fluorescence intensity caused by changing the ligand partial pressure. The method is illustrated by examining the binding of carbon monoxide to hemocyanin from the lobster Homarus americanus.
Decker, H., Connelly, P. R., Robert, C. H., and Gill, S. J. (1988). Nested allosteric interaction in tarantula hemocyanin revealed through the binding of oxygen and carbon monoxide. Biochemistry 27, 6901-8.
We have examined the competitive binding of oxygen and carbon monoxide to the multisubunit hemocyanin of the tarantula Eurypelma californicum. Employment of high-precision thin-layer methods has enabled detailed characterization of the pure oxygen and pure carbon monoxide binding curves, as well as binding curves performed under mixed-gas conditions. The pure oxygen binding curve and the displacement of oxygen by carbon monoxide at full ligand saturation are highly cooperative, but in the absence of oxygen, carbon monoxide binds noncooperatively. The results were analyzed globally within the framework of a nested allosteric model [Robert, C.H., Decker, H., Richey, B., Gill, S.J., & Wyman, J. (1987) Proc. Natl. Acad. Sci. U.S.A. 84, 1891-1895] which takes into account the hierarchy of subunit structure present in the macromolecule. The use of two ligands enables one to recognize two distinct levels of allosteric interaction functioning in the protein assembly. The binding characteristics of the allosteric states demonstrated for Eurypelma follow a similar pattern as those found earlier for Homarus americanus.
Decker, H., and Sterner, R. (1990). Nested allostery of arthropodan hemocyanin (Eurypelma californicum and Homarus americanus). The role of protons. J Mol Biol 211, 281-93.
Continuous oxygen binding curves for two arthropodan hemocyanins were performed at different pH values ranging from 7.0 to 8.7 and in the presence of physiological concentrations of the bivalent ions Ca2+ and Mg2+. The arthropods Eurypelma californicum and Homarus americanus are classified as chelicerata and crustaceans, respectively. Their structurally well-characterized hemocyanins are composed of, in the case of E. californicum 24 subunits, and in the case of H. americanus 12 subunits. The role of protons as allosteric effectors of the oxygen binding was analysed in terms of the nesting model, which assumes hierarchies of allosteric equilibria that are based on obvious structural hierarchies. For each hemocyanin, the smallest structural repeating unit, the 12-mer or the 6-mer, respectively, was regarded as the "allosteric unit". Two allosteric units are allosterically coupled within the native molecules. The analysis revealed that in accordance with the postulations of the classical Monod-Wyman-Changeux model protons as allosteric effectors do not change the oxygen affinities of the four postulated conformations, but influence the allosteric equilibria between them at two different hierarchical levels. Model- independent determination of the affinity constants for the binding of the first and the last oxygen molecule to the native hemocyanins and to the isolated half-molecules confirmed the affinities calculated according to the nesting model. The stepwise establishment of new conformations during the assembly process from monomers to the structurally identical repeating unit and further on to the native molecule is shown. Possible physiological advantages of allosterically coupled allosteric units in contrast to allosterically uncoupled ones are thought to be (1) the option to regulate oxygen binding on different levels of structural hierarchy and (2) the increase of the oxygen-carrying capacity.
Dehn, P. F., Haya, K., and Aiken, D. E. (1985). Adenylate energy charge, arginine phosphate and ATPase activity in juvenile Homarus americanus during the molt cycle. Comp Biochem Physiol [B] 81, 629-33.
Neither gill nor hepatopancreas exhibited significant differences in Na+, K+-ATPase activity with molt stage. Hepatopancreatic residual ATPase activity was significantly higher (F = 6.273) in post-molt animals; while gill residual ATPase activity exhibited no significant differences. Muscle AEC did not change with molt stage, but levels of ATP (F = 8.050) and ADP (F = 4.130) were significantly higher in premolt (D3 pleopod stage 5.0-5.5) animals; while levels of arginine phosphate (F = 6.981) were significantly higher in post-molt animals. Arginine phosphate/ATP and ATP/ADP ratios were highest in post-molt animals, but were not statistically significant. Although not significant, changes in Na+, K+-ATPase activity and AEC did suggest alterations in: enzyme activity that correlate with known osmotic compensations occurring during the water uptake and hardening/mineralization processes; and energy metabolism which occur during the molt cycle, respectively.
Demers, D. M., Metcalf, A. E., Talbot, P., and Hyman, B. C. (1996). Multiple lobster tubulin isoforms are encoded by a simple gene family. Gene 171, 185-91.
Microtubule proteins isolated from pleopod tegumental gland (PTG) tissue of the American lobster, Homarus americanus, reveal a complex tubulin (Tub) profile. To determine whether Tub heterogeneity in PTG is due to expression of a large tub gene family or the result of post- translational modification, a PTG cDNA library was constructed. Clones coding for both alpha- and beta-Tub were isolated, sequenced and found to contain open reading frames (ORFs) of 451 amino acids (aa). Alignments reveal phylogenetic clustering with other arthropods and identify unique changes in primary structure which may have functional significance. These clones, when used to probe restriction enzyme- digested lobster genomic DNA in transfer-hybridization experiments, revealed a simple banding pattern indicating a lobster tub gene family of limited complexity. Lobsters appear to make use of a small tub gene family and fulfill the varied functional requirements imposed upon cellular microtubules through post-translational modifications of relatively few gene products.
Denburg, J. L. (1972). An axon plasma membrane preparation from the walking legs of the lobster Homarus americanus. Biochim Biophys Acta 282, 453-8.
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Der Terrossian, E., Pradel, L. A., Kassab, R., and Thoai, N. V. (1969). Comparative structural studies of the active site of ATP-guanidine phosphotransferases. The essential cysteine tryptic peptide of arginine kinase from Homarus vulgaris muscle. Eur J Biochem 11, 482-90.
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Derby, C. D., Cate, H. S., and Gentilcore, L. R. (1997). Perireception in olfaction: Molecular mass sieving by aesthetasc sensillar cuticle determines odorant access to receptor sites in the Caribbean spiny lobster Panulirus argus. Journal of Experimental Biology 200, 2073-2081.
The responsiveness of chemoreceptor neurons depends on a combination of perireceptor and receptor events. Olfactory neurons of crustaceans are packaged into distinctive cuticular sensilla called aesthetascs. The cuticle of aesthetascs is thin and permeable, even though it does not contain any obvious surface pores or pore tubules. This suggests that this 'spongy' aesthetasc cuticle may act as a molecular sieve that restricts large odorant molecules from entering the sensilla and binding to the olfactory neurons. We examined whether this is so for the aesthetasc cuticle of the Caribbean spiny lobster Panulirus argus. We used a chromatographic column packed with aesthetasc cuticle and connected to a flow-through ultraviolet spectrophotometer to measure the elution times of ultraviolet- absorbent molecular mass markers between 165 and 2x10(6)Da. Molecules larger than approximately 8.5kDa had similar elution times, indicating that they did not penetrate the cuticle. Molecules smaller than 8.5kDa had longer elution times that were directly and inversely proportional to their molecular mass. These results suggest that aesthetasc cuticle excludes molecules larger than 8.5kDa from having access to the olfactory receptor neurons. We conclude that the molecular sieving capacity of the aesthetasc cuticle of P. argus is a perireceptor mechanism that is a critical determinant of the types of molecules capable of stimulating its olfactory receptors.
Deschenes, R. J., Mautner, H. G., and Marquis, J. K. (1981). Local anesthetics noncompetitively inhibit terbium binding to the exterior surface of nerve membrane vesicles. Biochim Biophys Acta 649, 515-20.
It has previously been shown that terbium binds to membrane vesicles prepared from the walking leg nerve of the lobster (Homarus americanus) with a high affinity Kd of 2.2 microM. Fluorescence of bound Tb3+ occurs via energy transfer from the aromatic residues of proteins (gamma ex = 280 nm; gamma em = 546 nm), and calcium inhibits Tb3+ binding competitively with a Ki of 1.8 mM. Displacement studies with EDTA demonstrate that more than 95% of the bound Tb3+ is at the vesicle exterior and is not being taken up by the vesicles. To investigate the putative role of Ca2+ in the interaction of local anesthetics with axonal membranes, lidocaine and the analogs GX-HCl and QX-314 were tested as inhibitors of Tb3+ binding. Inhibition by lidocaine is seen only at considerably higher doses (25 mM) than are required for conduction block of intact nerves (5 mM). Inhibition by lidocaine and the primary amine analog GX-HCl is entirely noncompetitive, whereas the quaternary ammonium derivative QX-314 appears to be a mixed competitive- noncompetitive inhibitor of Tb3+ binding. These data are not compatible with the hypothesis that there is a functionally essential cation binding site on the axonal membrane surface for which Ca2+ and local anesthetics compete, although local anesthetic action may be modified indirectly by altered calcium concentrations. Evidence is presented for a mechanism by which local anesthetics indirectly displace Tb3+ by altering the physical state of the axonal membrane.
Deschenes, R. J., Hilt, D. C., Marquis, J. K., and Mautner, H. G. (1981). Terbium binding to axonal membrane vesicles from lobster (Homarus americanus) peripheral nerve. A probe of calcium binding sites. Biochim Biophys Acta 641, 166-72.
Tb3+, a fluorescent trivalent cation with physicochemical properties similar to Ca2+, binds to peripheral nerve membrane vesicles prepared from the walking leg nerve bundle of the lobster (Homarus americanus). Saturable binding is measured for at least two classes of binding site. Bound Tb3+ can be displaced by other cations in the order: Ca2+ greater than Mg2+ = Zn2+ greater than NH4+. The binding of Tb3+ to the lower affinity site (KD(app) = 6.0 microM) is inhibitable by Na+, Mg2+ and Ca2+, whereas the higher affinity site (KD(app) = 2.2 microM) is only sensitive to Ca2+. Using this spectral probe the role of Ca2+ in peripheral nerve membrane function can be investigated.
Dingle, J. R., and Hines, J. A. (1974). Some enzymic reactions of adenine derivatives in the tail muscle of the lobster, Homarus americanus. Comp Biochem Physiol [B] 48, 1-10.
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Dixon, D., and Atwood, H. L. (1983). Lobster muscle and synapse respond to cortisol, a vertebrate hormone. Can J Physiol Pharmacol 61, 836-40.
Cortisol (0.28 mumol X L-1) applied to lobster (Homarus americanus) neuromuscular preparations produces a hyperpolarization in muscle fibers and an increase in amplitude of excitatory postsynaptic potentials. The effect appears to be surface-mediated, because of its rapid onset (within seconds). It is also Na+-K+ ATPase dependent, because ouabain blocks the effects. The effects are relatively short- lasting, and gradually subside within 15 min. The increase in excitatory postsynaptic potentials is attributed in part to increased quantal output of transmitter, and not to changes in muscle fiber membrane resistance. The effects of cortisol on neuromuscular transmission and membrane potential indicate that cortisol may have a physiological role in crustaceans.
Donahue, D. W., Bayer, R. C., and Loughlin, M. (1998). Examination of lead levels in the American lobster, Homarus americanus, from three sites in Maine. Journal of Shellfish Research 17, 1247-1249.
Bioaccumulation of lead in marine organisms has been a concern of researchers, government, and other food safety. The feeding habits of the American Lobster, Homarus Americanus, prior to recruitment into the fishery, gives rise to its potential accumulator of environmental contaminants. Three sites indicative of common lobster fishing areas were selected along the coast of Maine to assess and establish baseline level for lead contamination. From each of these sites, lobsters averaging in weight between 450 and 550 g, were collected and samples were taken from the gills, meats (mixture of tail and claw meat), and the hepatopancreas to be analyzed for lead concentration. Lead levels ranging from 20 to 101 ppb were found. Levels were higher in the hepatopancreas and meats than in the gills. There were interactions between location and body portion resulting from the higher levels in the hepatopancreas and meats. The levels found were significantly below the FDA/EPA limits on edible portions.
Duerr, J., and Ahearn, G. (1996). Characterization of a basolateral electroneutral Na+/H+ antiporter in Atlantic lobster (Homarus americanus) hepatopancreatic epithelial vesicles. J Exp Biol 199, 643-51.
Purified basolateral membrane vesicles (BLMVs) were prepared from Atlantic lobster (Homarus americanus) hepatopancreas using a Percoll density gradient technique. Enrichments of the Na+/K+-ATPase and alkaline phosphatase activities of these vesicles were 15.4- and 1.2- fold, respectively. The presence of amiloride-sensitive Na+/H+ exchange was demonstrated. Contrary to electrogenic 2Na+/1H+ exchange on apical membranes from the same tissue, kinetic studies of Na+ transport by these basolateral membranes indicate an electroneutral antiport with a Km of 28±1.7 mmol l-1 and a Jmax of 1.74±0.13 µmol mg-1 min-1. Amiloride interacted at a single binding site (Ki=39 µmol l-1) and external Li+ was shown to be an effective competitive inhibitor of the exchange process (Ki=493 µmol l-1). The presence of a membrane-potential-sensitive, Na+-accepting ion channel was also demonstrated. The basolateral Na+/H+ exchanger physiologically resembles members of the NHE family of Na+/H+ antiporters described in vertebrates and departs from the apical electrogenic system previously described in lobster. Whether or not the basolateral Na+/H+ antiporter is an NHE isoform remains to be determined.
Duerr, J. M., and Ahearn, G. A. (1998). Phorbol ester activation of an NHE-like electroneutral Na+/H+ antiporter in isolated E-cells of lobster (Homarus americanus) hepatopancreas. Journal of Experimental Zoology 281, 97-108.
The basolateral membrane of Atlantic lobster (Homarus americanus) epithelium possesses an electroneutral Na+/H+ antiporter that functionally resembles members of the vertebrate NHE family. Regulatory mechanisms of this antiporter in purified hepatopancreatic E-cell suspensions, produced with a centrifugal elutriation technique, were investigated. Suspensions routinely consisted of greater than 95% E-cells displaying greater than 90% viability. Intracellular pH (pH(i)) was monitored by loading cells with the fluorescent dye 2',7'- bis(carboxyethyl)-5,6-carboxyfluorescein (BCECF), and placing suspensions in a spectrofluorometer. Recovery from induced acid-loading was mediated by a Na+-dependent, dimethylamiloride-sensitive proton efflux. Antiport activation was a sigmoidal function of pH(i) at values below 7.0. Addition of 20 nM phorbol 12-myristate 13-acetate (PMA) to cells suspended in a lobster physiological saline (pH(0) = 7.4) increased pH(i) from 7.2 to 7.5 over a 10-min interval. Phorbol ester-induced activation of the Na+/H+ antiporter was due to an increased affinity for internal H+ (apparent pK was shifted toward more alkaline values) at the level of an internal H+- binding allosteric modifier site. No effect was observed when cells were exposed to 2 mu M 8-Br-cAMP. Phorbol ester activation of the lobster NHE-like Na+/H+ antiporter was inhibited by 10 nM bisindoylmaleimide I, a potent protein kinase C inhibitor. These results taken together suggest a remarkable conservation of Na+/H+ antiport across phyla. (C) 1998 Wiley-Liss, Inc.
Eichner, R. D., and Kaplan, N. O. (1977). Physical and chemical properties of lactate dehydrogenase in Homarus americanus. Arch Biochem Biophys 181, 490-500.
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Eichner, R. D., and Kaplan, N. O. (1977). Catalytic properties of lactate dehydrogenase in Homarus americanus. Arch Biochem Biophys 181, 501-7.
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Eichner, R. D., and Kaplan, N. O. (1978). Mechanism of lactic acid oxidation catalyzed by lactate dehydrogenase from the tail muscle of Homarus americanus. Arch Biochem Biophys 191, 666-72.
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El Haj, A. J., Tamone, S. L., Peake, M., Reddy, P. S., and Chang, E. S. (1997). An Ecdysteroid-responsive gene in a lobster - a potential Crustacean member of the steroid hormone receptor superfamily. Gene 201, 127-135.
The role of ecdysteroids in modulating exoskeletal growth during the moult cycle of Crustacea has been well described. However, little is known about the action of ecdysteroids at the level of gene transcription and regulation in Crustacea. This paper reports the cloning of an ecdysteroid responsive gene, HHR3, a potential Manduca sexta MHR3 homologue in the American lobster, Homarus americanus. Levels of HHR3 expression are up-regulated in response to in vivo injections of premoult concentrations (10(-6) M) of 20-hydroxyecdysone in the epidermal and muscle tissue of the lobster after 6 h. Maximal mRNA levels are observed after 21 h before returning to basal levels. In muscle tissue, elevated levels of HHR3 mRNA follow a time course similar to elevated actin mRNA expression in response to hormonal injection. In contrast, in eyestalk tissue, the HHR3 levels decline up to 21 h post-injection before rising to basal levels after 48 h. Eyestalk, epidermal and leg muscle tissue was extracted over the moult cycle to determine the levels of expression. In muscle, HHR3 is high during the premoult period that corresponds to the period of the moult cycle when the ecdysteroid titre is high. In the epidermis, HHR3 levels are also high during the premoult with elevated levels maintained into the postmoult period. In the eyestalk, mRNA levels of HHR3 show an opposite pattern of expression with low levels during premoult and postmoult and high levels found during the intermoult period. Our results provide novel evidence for an ecdysteroid responsive gene in a crustacean that has many similarities to MHR3 in Manduca and DHR3 in Drosophila melanogaster. This raises the question of whether a similar cascade of ecdysteroid responsive genes exist in other members of Arthropoda such as the Crustacea, as has been demonstrated in Drosophila. In addition, we provide further evidence for negative feedback regulation of ecdysteroids at the site of moult-inhibiting hormone (MIH) production in the lobster eyestalk. (C) 1997 Elsevier Science B.V.
El Haj, A. J. (1999). Regulation of muscle growth and sarcomeric protein gene expression over the intermolt cycle. American Zoologist 39, 570-579.
Crustacean muscle growth is associated with a hormonally mediated cyclical molt stage, The mechanisms by which fibre lengthening and hypertrophy occur in Crustaceans over the molt has been the subject of our and other researchers' investigations using histological, biochemical and molecular approaches, In this paper, we review our studies and present evidence for the different molecular mechanisms by which sarcomeric proteins are upregulated to achieve muscle sarcomere addition in lobsters during the molt. Synthesis of the sarcomeric proteins has been shown to increase during the premolt and postmolt phases in the leg and abdominal muscles coinciding with the addition of sarcomeres over ecdysis. This is in contrast to research on claw muscle demonstrating premolt atrophy. Our work and others' have investigated the factors which modulate this growth and turnover of muscle tissue in crustaceans. These changes in muscle turnover correspond with an elevated titre of circulating ecdysteroids and the role of these molting hormones in regulating sarcomeric mRNA and protein levels during cyclical muscle growth is discussed. Our results suggest that sarcomeric proteins may be controlled via both transcriptional and translational mechanisms during the molt interval and these findings are discussed in relation to previous research investigating muscle growth in Crustacea.
Elfvin, M., Levine, R. J., and Dewey, M. M. (1976). Paramyosin in invertebrate muscles. I. Identification and localization. J Cell Biol 71, 261-72.
By sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunodiffusion, we identified paramyosin in two smooth invertebrate "catch" muscles (Mytilus anterior byssus retractor and Mercenaria opaque adductor) and five invertebrate striated muscles (Limulus telson levator, Homarus claw muscle, Balanus scutal depressor, Lethocerus air tube retractor, and Aequipecten striated adductor). We show that (a) the paramyosins in all of these muscles have the same chain weights and (b) they are immunologically similar. We stained all of these muscles with specific antibody to Limulus paramyosin using the indirect fluorescent antibody technique. Paramyosin was localized to the A bands of the glycerinated striated muscles, and diffus fluorescence was seen throughout the glycerinated fibers of the smooth catch muscles. The presence of paramyosin in Homarus claw muscle, Balanus scutal depressor, and Lethocerus air tube retractor is shown here for the first time. Of the muscles in this study, Limulus telson levator is the only one for which the antiparamyosin staining pattern has been previously reported.
Elmamlouk, T. H., Gessner, T., and Brownie, A. C. (1974). Occurrence of cytochrome P-450 in hepatopancreas of Homarus americanus. Comp Biochem Physiol [B] 48, 419-25.
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Elmamlouk, T. H., and Gessner, T. (1976). Mixed function oxidases and nitroreductases in hepatopancreas of Homarus americanus. Comp Biochem Physiol C 53, 57-62.
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Engel, D. W., and Brouwer, M. (1986). Cadmium and copper metallothioneins in the American lobster, Homarus americanus. Environ Health Perspect 65, 87-92.
Lobsters were fed cadmium-rich oysters for 28 days, and the induction of cadmium metallothionein and its relation to concentrations of cadmium, copper, and zinc in the digestive gland and gills was determined. A portion of the tissues also was retained for determining the cytosolic distribution of these metals by gel filtration and ion- exchange chromatography. The digestive gland contained a majority of the cadmium, copper, and zinc, and both cadmium and zinc were actively accumulated from the oysters. Gel chromatography of the digestive gland cytosol showed that initially cadmium and zinc were bound to macromolecules with molecular weights of greater than 70,000, approximately 45,000 and less than 5000, and for copper greater than 70,000, 10,000-7,000, and less than 5000. Therefore, only copper was bound to a protein with a molecular weight in the range of metallothionein (i.e., 10,000-7,000). However, after feeding on cadmium- laden oysters for 28 days, both cadmium and copper were bound to the metallothionein-like protein. Further purification of the cadmium/copper protein by ion-exchange chromatography showed that a large portion of the copper and all of the cadmium did not bind to DEAE- Sephacel. The induction of cadmium metallothionein in the digestive gland is correlated with tissue cadmium concentration. There is, however, a tissue threshold concentration of cadmium of 80 to 100 micrograms Cd/g wet weight required for induction. Coincident with the induction of the cadmium metallothionein was a cytosolic redistribution of copper. The distribution of zinc was not affected.
Ennis, G. P., and Fogarty, M. J. (1997). Recruitment overfishing reference point for the American lobster, Homarus americanus. Marine and Freshwater Research 48, 1029-1034.
A 21-year series of annual estimates of egg production and recruitment in a Newfoundland lobster population indicates similar asymptotic relationships for recruitment to the fishery and to the adult population, both derived from legal stock estimates. Lines with slopes equal to the 90th-percentile and median survival ratios drawn through the origin of the egg production-adult recruitment scatterplot were examined as potential recruitment overfishing reference points for the Arnold's Cove lobster stock. If the inverse of the estimated lifetime egg production per recruit (E/R) for a given exploitation rate exceeds the slope of the selected reference point, the risk of recruitment overfishing is high. For the Arnold's Cove stock, the E/R level at a nominal 90% exploitation rate is estimated at 4.2% of the unfished population, compared with 2.5% for the overfishing reference point corresponding to the median survival ratio. Female lobsters at Arnold's Cove mature at sizes below the minimum legal size, providing a buffer against high exploitation rates. Small, scattered refugia of large lobsters could also help to explain how heavily exploited populations of this species persist at such a low level of egg production.
Estrella, B. T., and Morrissey, T. D. (1997). Seasonal movement of offshore American lobster, Homarus americanus tagged along the eastern shore of Cape Cod, Massachusetts. Fishery Bulletin 95, 466-476.
A total of 1,237 tagged American lobsters, Homarus americanus, with a carapace length (CL) range of 48 to 198 mm (mean CL of 104 mm) were liberated at three release stations off the eastern shore of Cape God, MA, between 1969 and 1971. By 1973, 332 (26.8%) of the tags were returned. Mean time at large was 112.5 days (range 0-897 d). One hundred and thirty (39.28) of the recaptured lobsters moved less than 10 km from their points of release. One hundred and fifty-one (45.5%) were recaptured within 10 to 40 km from their points of release; 51 (15.4%) at 40 km or more. Recapture depths and distances traveled were significantly greater in colder months. The distribution of these recaptures with time, depth, and location indicates seasonal movement to and from the edge of the continental shelf between fall and spring. The apparent reshoaling of these inshore-tagged lobsters to the eastern shore of Massachusetts in successive summers and the greater movement shown by females with ripe eggs at tagging, versus the movement of sublegal and nonovigerous female classes, suggest that the migration of this group of offshore lobsters is stimulated by seasonal changes in environmental cues in relation to hatching or reproductive needs (or both). Their relation to the Georges Bank-Southern Offshore stock unit, reproductive potential, and extensive seasonal movement into the southern and western Gulf of Maine, represent important considerations for resource managers and emphasize the need for further research on rate of stock interchange.
Factor, J. R. (1981). Unusually complex basement membranes in the midgut of two decapod crustaceans, the stone crab (Menippe mercenaria) and the lobster (Homarus americanus). Anat Rec 200, 253-8.
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Faumont, S., Simmers, J., and Meyrand, P. (1998). Activation of a lobster motor rhythm-generating network by disinhibition of permissive modulatory inputs. Journal of Neurophysiology 80, 2776-2780.
Rhythm generation by the gastric motor network in the stomatogastric ganglion (STG) of the lobster Homarus gammarus is controlled by modulatory projection neurons from rostral commissural ganglia (CoGs); blocking action potential conduction in these inputs to the STG of a stomatogastric nervous system in vitro rapidly renders the gastric network silent. However, exposure of the CoGs to low Ca2+ saline to block chemical synapses activates a spontaneously silent gastric network or enhances an ongoing gastric rhythm. A similar permissive effect was observed when picrotoxin was also superfused on these ganglia. We conclude that in the CoGs continuous synaptic inhibition is exerted on modulatory projection neuron(s) and that release from this inhibition allows strong activation of the gastric network.
Fenelon, V. S., Casasnovas, B., Faumont, S., and Meyrand, P. (1998). Ontogenetic alteration in peptidergic expression within a stable neuronal population in lobster stomatogastric nervous system. Journal of Comparative Neurology 399, 289-305.
In the adult lobster, Homarus gammarus, the stomatogastric ganglion (STG) contains two well-defined motor pattern generating networks that receive numerous modulatory peptidergic inputs from anterior ganglia. We are studying the appearance of extrinsic peptidergic inputs to these networks during ontogenesis. Neuron counts indicate that as early as 20% of development (E20) the STG neuronal population is quantitatively established. By using immunocytochemical detection of 5-bromo-2'-deoxyuridine incorporation, we found no immunopositive cells in the STG by E70. We concluded that the STG neuronal population remains quantitatively stable from mid- embryonic life until adulthood. We then investigated the ontogeny of FLRFamide- and proctolin-like peptides in the stomatogastric nervous system, from their first appearance until adulthood by using whole mount immunocytochemistry. Numerous FLRFamide-like-immunoreactive STG neuropilar ramifications were observable as early as E45 and remain thereafter. From E50 to the first larval stage, one to three STG somata stained, while somatic staining was not observed in larval stage II and subsequent stages. From E50 and thereafter, the STG neuropilar area was immunopositive for proctolin. One to two proctolinergic somata were detected in the STG of the three larval stages but were not seen in embryos, the post- larval stage or in adults. Thus, peptidergic inputs to the STG are present from mid-embryonic life. Moreover, whereas in the adult, STG neurons only contain glutamate or acetylcholine, some neurons transiently express peptidergic phenotypes during development. Although this system expresses an ontogenetic peptidergic plasticity, the STG neurons produce a single stable embryonic-larval motor output (Casasnovas and Meyrand [1995] J. Neurosci. 15:5703-5718). (C) 1998 Wiley-Liss, Inc.
Fenelon, V. S., Kilman, V., Meyrand, P., and Marder, E. (1999). Sequential developmental acquisition of neuromodulatory inputs to a central pattern-generating network. Journal of Comparative Neurology 408, 335-351.
The activity of the adult stomatogastric ganglion (STG) depends on a large number of aminergic and peptidergic modulatory inputs. Our aim is to understand the role of these modulatory inputs in the development of the central pattern-generating networks of the STG. Therefore, we analyze the developmental and adult expressions of three neuropeptides in the stomatogastric nervous system of the lobsters Homarus americanus and Homarus gammarus by using wholemount immunocytochemistry and confocal microscopy. In adults, red pigment concentrating hormone (RPCH)-like, proctolin-like, and a tachykinin-like immunoreactivity are present in axonal projections to the STG. At 50% of embryonic development (E50), all three peptides stain the commissural ganglia and brain, but only RPCH- and proctolin-like immunoreactivities stain axonal arbors in the STG. Tachykinin-like immunoreactivity is not apparent in the STG until larval stage II (LII). The RPCH- immunoreactive projection to the STG consists of two pairs of fibers. One pair stains for RPCH immunoreactivity at E50; the second RPCH-immunoreactive pair does not stain until about LII. One pair of the RPCH fibers double labels for tachykinin-like immunoreactivity. The adult complement of neuromodulatory inputs is not fully expressed until close to the developmental time at which major changes in the STG motor patterns occur, suggesting that neuromodulators play a role in the tuning of the central pattern generators during development. (C) 1999 Wiley-Liss, Inc.
Figler, M. H., Peeke, H. V. S., and Chang, E. S. (1997). Maternal aggression in American lobsters (Homarus americanus Milne-Edwards): Shelter-related encounters against non-maternal female conspecifics. Marine and Freshwater Behaviour and Physiology 30, 267-274.
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Figler, M. H., Peeke, H. V. S., and Chang, E. S. (1998). Shelter-related aggression between adult male conspecific intruders and resident maternal American lobsters (Homarus americanus) with eggs at different stages of embryogenesis. Marine and Freshwater Behaviour and Physiology 31, 151-166.
It has recently been shown that maternal (ovigerous/hatching) American lobsters (Homarus americanus) reliably out-compete non-maternal females for shelters. It is also known that nonmaternal females are subordinate to male conspecifics. To complement those studies, this maternal status effect on aggression was evaluated using intruding conspecific males. Resident maternal females were used whose eggs were at mid- embryogenesis, late-embryogenesis/hatching, or were 3-4 weeks post-hatching (non-maternal). The males reliably evicted resident females at all three stages. This male shelter competition advantage over maternal females is most likely produced by a combination of the necessity of the possession of a shelter by males for mating purposes, and the low shelter fidelity of ovigerous females due to their continual migratory behavior during the 9-12 month period of embryogenesis.
Figler, M. H., Cheverton, H. M., and Blank, G. S. (1999). Shelter competition in juvenile red swamp crayfish (Procambarus clarkii): the influences of sex differences, relative size, and prior residence. Aquaculture 178, 63-75.
Using a resident-intruder model, 24-h resident juvenile male and female red swamp crayfish, Procambarus clarkii, were intruded upon by same or opposite sex juvenile conspecifics that were the same size or larger than the residents. Relative size was significantly related to contest outcomes. Residents that were the same size as the intruders won a significantly higher proportion of their encounters than residents that were smaller than the intruders. Overall, neither sex nor prior residence was significantly related to contest outcome. There was clear shelter-related territorial defense in both male and female juveniles, and is very similar to that shown in adult conspecifics. The provision of shelter for juveniles in the aquaculture of P. clarkii is especially important because of the shelter competition advantage of adults. This indirectly increases juvenile vulnerability to heterospecific predation and cannibalism by conspecific adults and juveniles. (C) 1999 Elsevier Science B.V. All rights reserved.
Finelli, C. M., Pentcheff, N. D., Zimmer-Faust, R. K., and Wethey, D. S. (1999). Odor transport in turbulent flows: Constraints on animal navigation. Limnology and Oceanography 44, 1056-1071.
Odor plumes are common features of aquatic and terrestrial environments, forming an olfactory landscape through which animals must navigate to locate resources and avoid potential hazards. Time-averaged concentration profiles suggest that plumes consist of stable gradients in odor that animals may use for orientation. However, the lime scales necessary to generate such profiles are much longer than those typically associated with the neural or behavioral components of odor-mediated search. In contrast, plume measurements made at biologically relevant scales have indicated that turbulent plumes consist of discrete odor filaments separated by clean water. in addition, certain characteristics of individual odor filaments may vary consistently with distance from the odor source, thus providing directional information to a navigating organism. Unfortunately, there is no method to predict the distribution of these putative chemical cues, and our knowledge of odor dispersal is limited to very few laboratory flume studies. Here, we present the results of a held study during which we measured the distributions of the time-averaged concentration, properties of odor filaments, conditional statistics, and relevant hydrodynamic mixing parameters. Many of the observed odor plume characteristics have similar spatial distributions through a range of hydrodynamic conditions. The high degree of similarity in the distribution of many odor plume characteristics suggests that organisms can rely on any number of metrics to successfully orient in an odor plume. However, the temporal and spatial scales of odor dispersal may constrain the strategies used by navigating organisms and influence the efficiency of odor-mediated search. These field results should provide the basis for further empirical and theoretical work on chemosensory-mediated behavior of aquatic animals.
Flik, G., and Haond, C. (2000). Na(+) and Ca(2+) pumps in the gills, epipodites and branchiostegites of the European lobster Homarus gammarus: effects of dilute sea water. J Exp Biol 203, 213-220.
Crude homogenates and plasma-membrane-enriched fractions were prepared from the epithelium of the gills, epipodites and branchiostegites of intermoult European lobsters Homarus gammarus, and Na(+)/K(+)-ATPase, Ca(2+)-ATPase and Na(+)/Ca(2+) exchange activities were quantified in these tissues. Lobsters were kept in sea water (salinity 35 #) or were adapted to dilute sea water (22.1 #). The lobster hyperregulates haemolymph osmolarity and Ca(2+) levels in both media. Homogenates of the podobranchs, arthrobranchs and pleurobranchs had comparable Na(+)/K(+)-ATPase specific activities, and mean activities increased significantly for all three types of gills when the animals were kept in dilute sea water. In the epipodites and branchiostegites, Na(+)/K(+)- ATPase specific activities exceeded those in the gills, and exposure to dilute sea water greatly enhanced these activities. In sea water, 80 % of the total Na(+)/K(+)-ATPase activity is associated with the gills and epipodites (each tissue containing 40 %) and 20 % with the branchiostegites; in dilute sea water, the gills contained approximately 25 %, the epipodites 40 % and the branchiostegites approximately 35 % of the total activity, indicating the relative importance of the epipodites and branchiostegites for ionic hyperregulation in dilute media. In plasma membrane vesicles isolated from the gills, epipodites and branchiostegites, Ca(2+) transport driven by ATP and by a Na(+ )gradient was demonstrated. Exposure to dilute sea water enhanced Na(+)/Ca(2+ )exchange and Ca(2+)-ATPase activities in the epipodites and branchiostegites; in the gills, however, Ca(2+) transport activities decreased. The role of these tissues and enzymes in Na(+) and Ca(2+) handling by the lobster is discussed.
Foley, D. M., Stewart, J. E., and Holley, R. A. (1966). Isobutyl alcohol and methyl pentynol as general anesthetics for the lobster, Homarus americanus Milneedwards. Can J Zool 44, 141-3.
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Forget, J., Pavillon, J. F., Menasria, M. R., and Bocquene, G. (1998). Mortality and LC50 values for several stages of the marine copepod Tigriopus brevicornis (Muller) exposed to the metals arsenic and cadmium and the pesticides atrazine, carbofuran, dichlorvos, and malathion. Ecotoxicology and Environmental Safety 40, 239-244.
The toxicity of three insecticides (carbofuran, dichlorvos, malathion), an herbicide (atrazine), and two metals (arsenic and cadmium) to ovigerous females, copepodids, and nauplii of Tigriopus brevicornis was determined by 96-h semistatic (or static-renewal) bioassays, Freshly prepared aqueous stock solutions of these pesticides and metals were diluted to appropriate concentrations. Mortalities were recorded and test solutions were changed completely each day up to 96 h, The rate of mortality was analyzed for linear regressions, and LC50 values were determined by probit analysis, LC50 values for ovigerous T, brevicornis females were 153.2 mu g liter(-1) for atrazine, 59.9 mu g liter(-1) for carbofuran, 47.9 mu g liter(- 1) for cadmium, 27.5 mu g liter(-1) for arsenic, 24.3 mu g liter(-1) for malathion, and 4.6 mu g liter(-1) for dichlorvos, Comparison of the overall toxicities of these pesticides and metals indicated that dichlorvos was the most toxic substance to T, brevicornis, followed by malathion, arsenic, cadmium, carbofuran, and atrazine. Available LC,, data indicate that marine copepods are more sensitive to pollutants than Daphnia magna, Acartia tonsa, and Tisbe battagliai, or as sensitive as the mysid Mysidopsis bahia. (C) 1998 Academic Press.
Freire, J., and Gonzalez-Gurriaran, E. (1998). New approaches to the behavioural ecology of decapod crustaceans using telemetry and electronic tags. Hydrobiologia 372, 123-132.
Decapod crustaceans have complex life histories and behaviour ire aspects such as foraging, mating and reproduction, moulting and growth, habitat selection and migration. New technologies have enabled us to use an individual, field-based approach to analyze these problems, although they have been less developed in decapods than in marine vertebrates. These new possibilities are discussed here mainly from a biological point of view. There is a brief review of previous applications of telemetry to analyze habitat selection, foraging behaviour, energetics, moulting site selection and migrations in decapods, and two case studies are discussed in more detail. The first one refers to the study of differences in habitat use and movement patterns in juveniles and adults of coastal species that show ontogenetic habitat shifts, related to differences in selective pressures affecting both life history stages (predation risk, and growth and reproduction optimization). The second case study is dedicated to the migratory patterns in spider crabs combining telemetry and electronic tags. Operational limitations in tracking make it impossible to get detailed information on movement patterns during migration, which in turn involve an important bathymetric gradient and a change in the oceanographic environment (mainly temperature). Monitoring depth and temperature in the immediate habitat of the animals, using electronic data storage tags recovered by the fishery, allow for movement patterns to be modeled using supplementary information on the topography and hydrography of the study area. This approach is being tested using both telemetry and electronic tags simultaneously.
Furukohri, T., Okamoto, S., and Suzuki, T. (1994). Evolution of phosphagen kinase (III). Amino acid sequence of arginine kinase from the shrimp Penaeus japonicus. Zoolog Sci 11, 229-34.
The amino acid sequence of arginine kinase (AK) from the shrimp Penaeus japonicus has been determined chemically. It consists of 355 amino acid residues, and has a calculated molecular mass of 40,018 Da. The amino acid sequence of Penaeus AK showed 91% and 51% identity, respectively, with those of AKs from the lobster Homarus vulgaris and the abalone Nordotis madaka. It also showed significant homology (39-43%) with vertebrate or invertebrate creatine kinases and annelid glycocyamine kinase, suggesting that these enzymes evolved from a common origin.
Gagosian, R. B. (1975). Sterols of the lobster (Homarus americanus) and the shrimp (Pandalus borealis). Experientia 31, 878-80.
In this study we have analyzed the sterol compositions of two continental shelf species of crustacea, the lobster (Homarus americanus) and the shrimp (Pandalus borealis). Cholesterol was found to be the most abundant sterol in these two species with smaller amounts of desmosterol, 24-methylcholesterol, 24-ethylcholesterol, 24- methylenecholesterol and 22-dehydrocholesterol.
Gagosian, R. B., and Bourbonniere, R. A. (1976). Isolation and purification of the molting hormones from the American lobster (Homarus americanus). Comp Biochem Physiol [B] 53, 155-61.
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Ganter, G. K., Heinrich, R., Bunge, R. P., and Kravitz, E. A. (1999). Long-term culture of lobster central ganglia: Expression of foreign genes in identified neurons. Biological Bulletin 197, 40-48.
The ventral nerve cords of lobsters (Homarus americanus) can be cultured in vitro for at least 7 weeks. Over this period, neurons maintain their normal electrophysiological features and continue, among other measures of neuronal health, to synthesize RNA and proteins. One application of this culture system is demonstrated: the manipulation of gene expression in identified neurons. After intracellular injection of complementary RNA (cRNA) encoding green fluorescent protein (GFP), the amount of protein product measured by fluorescent confocal microscopy increases for 4 days and then decreases to background by day 10. Thus, translation of the injected message must have increased for 4 days before declining. Moreover, after injection of cRNA encoding beta-galactosidase, the levels of enzyme activity were measured using a fluorogenic substrate, revealing a peak of beta-galactosidase activity at 6 to 9 days; this activity was still delectable for at least 10 days after injection. Therefore, either GFP or beta-galactosidase can be used as an injectable marker, allowing in vivo quantitation of expression in individual cells over time. We measured longlasting expression of these proteins after a single injection, suggesting that it may be possible to manipulate the levels of expression of any gene of interest.
Gardner, C. (1997). Effect of size on reproductive output of giant crabs Pseudocarcinus gigas (Lamarck): Oziidae. Marine and Freshwater Research 48, 581-587.
Fecundity and egg size of giant crabs (Pseudocarcinus gigas) were determined from egg masses of 162 crabs sampled from three sites in south-eastern Australia: western Victoria, western Tasmania and eastern Tasmania. Crabs ranged in carapace length from 126 to 220 mm and egg number ranged from 830000 to 2500000. Egg number and egg size increased with size of female. There appeared to be a decline in number of eggs and size of eggs with successive broods produced between moults. Sampling locality appeared to have little effect on reproductive output. Regression of an allometric model of log egg number to log crab size had a slope of 1.76 which was significantly less than 3.0. This indicates there is not a simple volumetric relationship between the variables, which would tend to occur if increasing fecundity with female size was a simple function of increased body space available for ovarian development. This pattern appeared to be a function of decreasing egg number and size with successive broods, and the trend of increasing egg size with female size.
Garzino, V., and Reichert, H. (1994). Early embryonic expression of a 60-kD glycoprotein in the developing nervous system of the lobster. J Comp Neurol 346, 572-82.
To investigate the developmental processes that generate the crustacean nervous system, we used a monoclonal antibody that recognises an antigen that is expressed in the developing embryonic nervous system of the lobster, Homarus gammarus. Expression of this antigen commences early in embryogenesis, occurs in all parts of the embryonic central and peripheral nervous systems, and continues into adulthood. Initial expression in the central nervous system correlates with the onset of neuronal process outgrowth. Light microscopic analysis shows that the antigen is found surrounding the cell bodies and processes of all neurons. Biochemical analysis indicates that the antigen is a glycoprotein with an apparent molecular weight of 60 kD. Due to the early embryonic onset of its expression, this antigen is a useful cellular label for visualisation of pattern formation in the developing nervous system; this is documented in detail for the developing stomatogastric nervous system. The fact that the 60-kD antigen is expressed early in embryogenesis throughout the nervous system suggests that it might play an important role in the development of the lobster nervous system.
Gerencser, G. A., Ahearn, G. A., and Cattey, M. A. (1996). Antiport-driven sulfate secretion in an invertebrate epithelium. J Exp Zool 275, 269-76.
A novel invertebrate gastrointestinal transport mechanism has been shown to couple chloride/sulfate exchange in an electrogenic fashion. In the lobster, Homarus americanus, the hepatopancreas, or digestive gland, exists as an outpocketing of the digestive tract, representing a single cell layer separating the gut lumen and an open circulatory system comprised of hemolymph. Investigations utilizing independently prepared brush-border and basolateral membrane vesicles revealed discrete antiport systems which possess the capacity to bring about a transcellular secretion of sulfate. The luminal antiport system functions as a high affinity, one-to-one chloride-sulfate exchanger that is stimulated by an increase in luminal hydrogen ion concentration. Such a system would take advantage of the high chloride concentration of ingested seawater, as well as the high proton concentrations generated during digestion, which further suggests a potential regulation by resident sodium-proton exchangers. Exchange of one chloride for one divalent sulfate ion provides the driving force for electrogenic vectorial translocation. The basolateral antiport system was found to be electroneutral in nature, responsive to gradients of the dicarboxylic anion oxalate, while lacking in proton stimulation. No evidence of sodium-sulfate cotransport, commonly reported for the brush border of vertebrate renal and intestinal epithelia, was observed in either membrane preparation. The two antiporters together can account for the low hemolymph to seawater sulfate levels previously described in decapod crustaceans. A secretory pathway for sulfate based upon electrogenic chloride-antiport may appear among invertebrates partly in response to digestion taking place in a seawater environment.
Ghiasuddin, S. M., and Matsumura, F. (1981). DDT inhibition of Ca-Mg ATPase from peripheral nerves and muscles of lobster, Homarus americanus. Biochem Biophys Res Commun 103, 31-7.
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Ghiasuddin, S. M., Kawauchi, S., Matsumura, F., and Doherty, J. D. (1982). Role of phospholipids in the inhibitory action of DDT and permethrin on the nerve ATPase of lobster, Homarus americanus. Biochem Pharmacol 31, 1483-9.
Efforts were made to understand the nature of the site of 1,1-bis-(p- chlorophenyl)-2,2,2-trichloroethane (DDT) inhibition of nerve ATPase. THe phospholipid content of nerve preparations from the walking leg of the lobster was reduced by treating them with phospholipase A, or with a chloroform-methanol mixture at -75 degrees. By these treatments the enzymes lost approximately 70 or 95% of their phospholipids and 50-80% of their Na,K- and Ca-ATPase activities. The lost ATPase activities could be partially restored by the addition of phospholipids, either the ones extracted from the lobster nerves or those from commercial sources. ATPase inhibition by DDT and permethrin was found to be highest in preparations where the phospholipids were removed by the above treatments, next highest with the untreated original enzyme, and least with the reconstituted ATPase regardless of the source of phospholipids used for reconstitution. This tendency was more pronounced in the case of Ca-ATPase. The effects of DDT and permethrin on inhibition of reconstituted Ca-ATPase were higher when the insecticide was first added to the protein portion and the enzyme was then reconstituted with the phospholipids, than when the same amount of insecticide was first added to the phospholipids which were then used for reconstitution.
Gilgan, M. W., and Idler, D. R. (1967). The conversion of androstenedione to testosterone by some lobster (Homarus americanus Milne Edwards) tissues. Gen Comp Endocrinol 9, 319-24.
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Gilgan, M. W., and Zinck, M. E. (1975). Response of the adult lobster (Homarus americanus) to graded and multiple doses of ecdysterone. Comp Biochem Physiol A 52, 261-4.
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Gilgan, M. W., and Burns, B. G. (1976). The successful induction of molting in the adult male lobster (Homarus americanus) with a slow-release form of ecdysterone. Steroids 27, 571-80.
In an initial, and then a confirmatory experiment, adult, male lobsters were injected with solvent, ecdysterone (E, 2.0 mug/g live weight) or ecdysterone acetate (EAc, 2.5 or 5.0 mug/g live weight) emulsions in Freund's incomplete adjuvant (FIA). Control lobsters underwent no molts and only one death in the two cases. The E treated animals all died (average: exp. 1, 19.2 +/-2.1 days; exp. 2, 25.3 +/- 8 days). After the lobsters were treated twice with 2.5 mug EAc/g live weight, in the first experiment, four out of five molted and one died; in the second experiment six out of eight molted, one died and one remained refractory. The high EAc dose resulted in five deaths, one molt and two pseudomolts after one treatment. It is concluded that the use of the oil emulsion and EAc sufficiently slowed the release of free ecdysterone to allow complete premolt development in the lobster.
Gilgan, M. W., and Burns, B. G. (1977). Molt induction in lobsters (Homarus americanus) by intramuscular injection of ecdysterone triacetate. Experientia 33, 1114-5.
The principal component of the successful, molt-inducing ecdysterone acetate mixture was established as ecdysterone triacetate and shown to have the same activity as the acetate mixture. The triacetate induced ecdysis in male lobsters collected in winter and summer and in female lobsters collected in winter. Intramuscular injections of triacetate in ethanol were as effective as those with oil emulsions.
Gilles, R., and Schoffeniels, E. (1968). [Fixation of 14CO2 by amino acids in the ventral eerve chain of the crustacean Homarus vulgaris M. Edw.]. Arch Int Physiol Biochim 76, 441-51.
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Gilles, R., and Schoffeniels, E. (1969). Metabolism of arabinose in the ventral nerve cord of the lobster Homarus vulgaris (M.Edw.). Comp Biochem Physiol 28, 1145-52.
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Gilles, R., and Schoffeniels, E. (1969). Metabolic fate of glucose and pyruvate in the nerve cord of Homarus vulgaris (M. Edw.) and Astacus fluviatilis (F.). Comp Biochem Physiol 28, 417-23.
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Giri, T., and Dunham, D. W. (1999). Use of the inner antennule ramus in the localisation of distant food odours by Procambarus clarkii (Girard, 1852) (Decapoda, Cambaridae). Crustaceana 72, 123-127.
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Giulianini, P. G., Smullen, R. P., Bentley, M. G., and Ferrero, E. A. (1998). Cytological and immunocytochemical study of the sinus gland in the Norway lobster Nephrops norvegicus (L.). Invertebrate Reproduction & Development 33, 57-68.
Light and transmission electron microscopic examination of the X-organ-sinus gland complex in adult Nephrops norvegicus reveals a high density of active neurosecretory axon endings (53%) abutting onto an undulatory-release surface. At least six different categories of neurosecretory granules and related vesicles have been identified on the basis of their texture, electron density, and diameter. Computer-aided three- dimensional reconstruction of N. norvegicus sinus gland defined by its fuchsinophilia on 2.5 mu m serial sections shows a multilobed organ 1.25x 10(-2) mm(3) in volume. Immunocytochemical studies were carried out using polyclonal antibodies raised against purified Astacus leptodactylus CHH (Gorgels-Kallen and Van Herp, 1981) and Homarus americanus GIH (Meusy and Soyez, 1991). Immunocytochemical localization of CHH and GIH (VIH) at the LM and EM level specifically locate the massive presence of CHH and a more superficial and scattered distribution of GIH in the axon endings. Under TEM, specificity in type and content of granules appears to be confined to single axons. Heterologous antibodies reacting with even phylogenetically distant taxa stress a conservative homology at least of some common reactive epitopes.
Gnatzy, W. (1984). 'Campaniform' structures on lobster antennae are dermal glands. Cell Tissue Res 236, 729-31.
The dome-shaped ('campaniform') cuticular structures found in small depressions on the lateral antennular flagella of the lobster (Homarus gammarus) were investigated by means of electron-microscopic methods. Each dome (diameter: 4-5 micron), which is surrounded by a 3-5 micron wide cuticular collar, is associated with a cell (soma size: long axis 90 micron, short axis 24 micron) showing fine-structural details characteristic of a dermal gland, e.g., a ductule lined by thin (cuticulin-like) cuticle and a well-developed granular endoplasmic reticulum. This ductule ends within the dome, which consists of spongious cuticle and, when seen from outside, resembles the cuticular cap of a typical campaniform sensillum of insects (Fig. 1 b). The fine- structural findings, especially the lack of any sensory element, are clear evidence against previous descriptions of these structures as representing 'campaniform sensilla of crustaceans'.
Goldberg, D., Nusbaum, M. P., and Marder, E. (1988). Substance P-like immunoreactivity in the stomatogastric nervous systems of the crab Cancer borealis and the lobsters Panulirus interruptus and Homarus americanus. Cell Tissue Res 252, 515-22.
The distribution of substance P-like immunoreactivity in the stomatogastric nervous systems of three decapod crustacean species, Cancer borealis, Homarus americanus, and Panulirus interruptus, was studied. The stomatogastric ganglion showed dense staining in the neuropil, but none in the somata. A single neuron stained in the esophageal ganglion. Lucifer yellow backfills and intracellular injections followed by incubation with the substance P antibody showed that the axons of this neuron project into the inferior esophageal nerves towards the paired commissural ganglia. The commissural ganglia showed a pronounced projection from a large bundle of fibers in the anterior medial portion of the circumesophageal connective. Additionally, less dense neuropil and stained somata were seen in the commissural ganglia. Staining was completely blocked by preabsorption with authentic substance P, physalaemin, eledoisin, and substance K. These data suggest that in the nervous system of crustacean species a molecule with C-terminal homology to substance P and other tachykinins is released as a neuroregulator in the stomatogastric ganglion.
Gomez, G., Voigt, R., and Atema, J. (1999). Temporal resolution in olfaction III: flicker fusion and concentration-dependent synchronization with stimulus pulse trains of antennular chemoreceptor cells in the American lobster. Journal of Comparative Physiology a-Sensory Neural and Behavioral Physiology 185, 427-436.
To understand how chemoreceptor organs may extract temporal information from odor plumes, we investigated the frequency filter properties of lobster chemoreceptor cells. We used rapid stimulation and high-resolution stimulus measurement for accurate stimulus control and recorded extracellular responses from chemoreceptors in the lobster lateral antennule in situ. We tested 16 hydroxyproline-sensitive cells with a series often 100-ms pulses at 10, 100 and 1000 mu mol l(-1) at stimulation frequencies from 0.5 Hz to 4 Hz. Receptor cell responses could accurately encode 10 mu mol l(-1), but not 100 or 1000 mu mol l(-1) pulses, delivered at rates of 4 Hz. Flicker-fusion frequency and synchronization with the stimulus pulse train were concentration dependent: performance rates above 1 Hz became poorer both with increasing pulse amplitude and frequency. Flicker fusion frequency was 3 Hz for 100 mu mol l(- 1) pulses and 2 Hz for 1000 mu mol l(-1) pulses. Individual cells showed differences in their stimulus pulse following capabilities, as measured by the synchronization coefficient. These individual differences may form a basis for coding temporal features of an odor plume in an across-fiber pattern.
Gosselin, L. A. (1997). An ecological transition during juvenile life in a marine snail. Marine Ecology-Progress Series 157, 185-194.
Ecological shifts occurring after metamorphosis in benthic marine invertebrates have received much less attention than the more conspicuous transition occurring at metamorphosis and settlement. It remains unclear whether postmetamorphic shifts occur simultaneously or at different times, and whether the shifts occur over brief, discrete periods or are extended or even continuous through juvenile life. The present study of the muricid gastropod Nucella emarginata examines the ontogeny of vulnerability to desiccation, of susceptibility to hatchling predators, of shell coloration, and of distribution among microhabitats as a function of snail size. All the above parameters changed substantially over approximately the same size range. Individuals acquired the ability to survive direct exposure to desiccation for the duration of a low tide over the 3.1-6.5 mm shell length (SL) size range, and also became virtually invulnerable to hatchling predators when they reached 6.5 mm SL. The shift in mortality factors was paralleled by a change in shell colour over the 3-7 mm SL size range, and in distribution over the 3-8 mm SL size range. All shifts were therefore completed by the time individuals reached 8 mm, or by the age of similar to 4 mo based on growth rates in the laboratory. The coordination of these ecological changes in N. emarginata over the 3-8 mm SL size range constitutes an ecological transition that partitions postmetamorphic life into 2 periods, early juvenile and late juvenile/adult, each with distinct selective environments and corresponding adaptive traits. A similar ontogenetic transition has also been documented in juvenile lobsters, and studies of juveniles of other species reveal that comparable ecological changes are common among benthic marine invertebrates. Interspecific variation is nevertheless expected in the exact nature and timing of the transition, particularly as a result of differences in initial juvenile size, growth rate, adult size, ability to learn, and motility.
Goudard, F., Paquet, F., Durand, J. P., Milcent, M. C., Germain, P., and Pieri, J. (1994). Biodynamic study of americium-241 accumulation in the cytosol of the hepatopancreas of the lobster Homarus gammarus. Biochem Mol Biol Int 33, 841-51.
In the lobster, most of the radionuclides ingested with contaminated food are concentrated in the digestive gland. Americium-241 accumulation in the hepatopancreas of the lobster was studied during the digestive cycle. Fractionations of cytosols at different times after ingestion of radioactive preys were performed by gel permeation chromatography to determine the distribution of 241Am in the different macromolecular components. 241Am was associated with ferritin during the whole digestive cycle. This observation suggests a correlation between 241Am distribution pathways and iron metabolism. The distribution of 241Am present in the other cytosolic proteins followed two major steps of accumulation which may be correlated to the evolution of the two main cellular types playing an important role in the digestive cycle (B and R type cells).
Goudard, F., Milcent, M. C., Durand, J. P., Germain, P., Paquet, F., and Pieri, J. (1998). Subcellular and molecular localisation of different radionuclides (caesium, americium, plutonium and technetium) in aquatic organisms. Radiation Protection Dosimetry 75, 117-124.
Artificial radionuclides are released into the aquatic environment. Some of them are incorporated into aquatic organisms. An attempt has been made to elucidate the accumulation of radionuclides within the intracellular constituents of these organisms. On chronically radiolabelled animals (labelled sea water), the subcellular localisation of Am-241 in the digestive gland cells of periwinkles and of oysters was determined. Similar experiments were performed on the hepatopancreas of the lobster (labelled food) with Am-241, Pu-238 and Tc-95(m), and in pyloric caeca of sea-stars with Am- 241, Cf-252 and Tc-95(m). The distribution of Cs-137 was studied in cytosolic fractions of muscle and liver of eels and in the oyster. Distribution of radioelements appeared to correlate with the metabolic pathways of the species studied and with the chemical nature of the radionuclide. The results provide data in radioprotection research and may explain the biokinetics which were observed for whole organisms.
Goudeau, M., Talbot, P., and Harper, R. (1987). Mechanism of egg attachment stalk formation in the lobster, Homarus. Gamete Res 18, 279-89.
We have examined the formation of the egg attachment stalk in the lobsters Homarus americanus and H. gammarus. The formation of the stalk is similar in both species. Ovulated oocytes are surrounded by a single coat, envelope 1, composed of layers 1A and 1B. After passage through the gonopore and exposure to sea water, envelope 1 swells and becomes sticky. A second coat, envelope 2, forms between the oocyte and envelope 1 during a complex cortical reaction initiated after fertilization. Eggs pass over the ventral surface of spawning females to the region of the pleopods, where they stick by means of layer 1A to each other and to the ovigerous setae. Layers 1A and 1B are soft and pliable at this time. During egg attachment, the pleopods beat vigorously and cause envelope 1 to stretch and form attachment stalks. Beating probably also causes the attachment stalks to twist and wrap around the ovigerous setae. After the egg mass is secured to the ovigerous setae, envelope 1 of both the attachment stalk and egg coat condenses to form a tough material capable of securing the egg mass to the pleopods for intervals up to 16 months. After larvae hatch, portions of the egg coats and the attachment stalks are retained on the ovigerous setae until the female undergoes her next molt.
Goudey, L. R., and Lang, F. (1974). Growth of crustacean muscle: asymmetric development of the claw closer muscles in the lobster, Homarus americanus. J Exp Zool 189, 421-7.
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Govind, C. K., and Lang, F. (1974). Neuromuscular analysis of closing in the dimorphic claws of the lobster Homarus americanus. J Exp Zool 190, 281-8.
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Govind, C. K., and Meiss, D. E. (1979). Quantitative comparison of low- and high-output neuromuscular synapses from a motoneuron of the lobster (Homarus americanus). Cell Tissue Res 198, 455-63.
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Govind, C. K., De Rosa, R. A., and Pearce, J. (1980). Presynaptic dense bars at neuromuscular synapses of the lobster, homarus americanus. Cell Tissue Res 207, 81-8.
The three dimensional ultrastructure of presynaptic dense bars was examined by serial section electron microscopy in the excitatory neuromuscular synapses of the accessory flexor muscle in the limbs of larval, juvenile, and adult lobsters. The cross-sectional profile of the dense bar resembles an asymmetric hourglass, the part contacting the presynaptic membrane being larger than that projecting into the terminal. The bar has a height of 55-65 nm and varies in length from 75- 600 nm. In its dimensions it resembles the dense projections in the synapses of the CNS of insects and vertebrates. The usual location of these dense bars is at well defined synapses, though a few are found at extrasynaptic sites either in the axon or terminal. In the latter case the bars are close to synapse-bearing regions, particularly in the larval terminals, suggesting that the extrasynaptic bars denote early events in synapse formation, In all cases the bars are intimately associated with electron lucent, synaptic vesicles located on either side, in the indentation of its hourglass-shaped cross sectional profile. The vesicles occur along the length of the bar and contact the presynaptic membrane. Consequently the dense bar may serve to align the vesicles at the presynaptic membrane prior to exocytosis. A similar role has been suggested for the presynaptic dense bodies at the neuromuscular junction of the frog, where synaptic vesicles form a row on either side of this structure.
Govind, C. K., and Wiens, T. J. (1985). Innervation of the limb accessory flexor muscle in several decapod crustaceans. I. Anatomy. J Neurobiol 16, 317-28.
The innervation of the accessory flexor muscle of the limbs of several decapod crustaceans was studied by means of vital staining, with methylene blue and electron microscopy. Three patterns of innervation were found. In the first pattern, the distal (DAFM) and proximal (PAFM) heads of the accessory flexor muscle were supplied by two axons (a thick and a thin) which travel in a private nerve along the length of the merus. This pattern was found in the crab (Cancer) and the lobster (Homarus), and conforms to the classical pattern established in the literature. In the second pattern, the nerve to the DAFM is made up of conjoined branches of the flexor and accessory flexor nerves. Consequently, the DAFM receives at least five axons in the portunid crabs, Carcinus, Callinectes, and Ovalipes, and occasionally six axons in Ovalipes. The PAFM in those portunids receives the usual two axons. In the third pattern, based on preliminary observations on the grapsid crab, Pachygrapsus, "super-innervation" of the accessory flexor muscle appears to include not only five axons to the DAFM but also at least three to the PAFM. In all species, methylene blue staining of the axon terminations revealed a regular pattern of blebs which are thought to correspond to synaptic terminals as revealed by electron microscopy.
Govind, C. K., Stephens, P. J., and Eisen, J. S. (1985). Polyneuronal innervation of an adult and embryonic lobster muscle. J Embryol Exp Morphol 87, 13-26.
Motor innervation of the deep extensor muscle in the abdomen of lobsters (Homarus americanus) was compared in adults and embryos using electrophysiological techniques. There is widespread innervation of the adult muscle by the common excitor and inhibitor axons and regionally restricted or private innervation by three more excitor axons. In the embryo the earliest sign of functional innervation revealed a single inhibitory and two to three excitatory axons thus denoting simultaneous innervation by the full complement of axons. In corroboration, serial- section electron microscopy revealed several axon profiles invading the embryonic deep extensor muscles and giving rise to well-defined neuromuscular synapses with presynaptic dense bars. Innervation patterns to homologous regions of the embryonic and adult muscles were similar, consisting of a few large inhibitory synapses and many small excitatory ones. Consequently the adult pattern of polyneuronal innervation occurs simultaneously and in toto during embryonic development.
Govind, C. K., and Potter, D. J. (1987). Development of bilateral asymmetry in sensory innervation to lobster claws. Brain Res 432, 131-9.
Sensory innervation to the paired claws of the lobster. Homarus americanus, was examined during their differentiation from a bilaterally symmetric state to an asymmetric state of a slender cutter and a stout crusher claw. This was done by estimating the total number and size distribution of axons in the second nerve root which provides most (approximately 90%) of the innervation to the claws and has few, bilaterally distributed motor axons. The paired claws which are undifferentiated and resemble each other in the 1st larval stage correspondingly have nerve roots that are bilaterally symmetric. In early juvenile (4th and 5th) stages when claw type is determined, as well as in subsequent (6th, 7th, 8th, 16th) juvenile stages when the claws gradually differentiate into cutter and crusher types, the pair.
Govind, C. K., Kirk, M. D., and Pearce, J. (1988). Highly active neuromuscular system in developing lobsters with programmed obsolescence. J Comp Neurol 272, 437-49.
The primary locomotory apparatus in the three larval stages of the lobster, Homarus americanus, are paddlelike structures on the thoracic appendages called exopodites, which beat almost continuously. Consequently their power and return-stroke muscles are examples of highly active but short-lived neuromuscular systems. The muscles, which are well vascularized, are of the fast type with 2-3-micron sarcomere lengths and 6 thin filaments surrounding a thick one. The most striking feature, however, is the large volume of mitochondria making up 40-50% of the fiber. They appear as simple cylinders packed several layers deep along the periphery of the fiber and as large, multibranched forms distributed throughout the fiber and subdividing it into smaller units. The motor innervation to the return-stroke muscle is via 3 excitatory axons, which generate large junctional potentials and twitch contractions. The muscle is densely populated with large neuromuscular synapses, most of which have a well-defined active site or dense bar denoting the site of transmitter release. Altogether this motor system is specialized for prolonged activity. Atrophy of the neuromuscular system occurs by the late larval third stage. The muscle fibers lose their identity, fuse, and become vacuolated. The myofibrils condense and erode and the mitochondria are lost. Atrophy of motor innervation is gradual with individual axons dropping out. The largest axon providing most of the innervation is the first to degenerate. Early degenerative changes affect the axon and neuromuscular terminals but not the synaptic contacts, dense bars, and vesicles, which appear intact. Continued atrophy in the postlarval fourth stage reduces the exopodites to vestiges. Thus the return-stroke muscle of the larval exopodites in which muscle fiber and motoneurons are identifiable permits study of the interaction between a neuron and its target muscle undergoing programmed obsolescence.
Goy, M. F., Mandelbrot, D. A., and York, C. M. (1987). Identification and characterization of a polypeptide from a lobster neurosecretory gland that induces cyclic GMP accumulation in lobster neuromuscular preparations. J Neurochem 48, 954-66.
Several observations suggest that cyclic GMP might regulate some aspect of neuromuscular physiology or metabolism in the lobster. Homarus americanus: lobster muscle is one of the richest known sources of cyclic GMP-dependent protein kinase, the preparation contains several phosphoproteins whose state of phosphorylation is affected by cyclic GMP more effectively than by cyclic AMP, and guanylate cyclase and phosphodiesterase are active in this tissue. However, no factor has yet been identified that alters lobster muscle cyclic GMP levels. We have screened extracts of neural and neurosecretory structures for the capacity to promote cyclic GMP accumulation in isolated exoskeletal muscles. Extracts of the sinus gland (a neurohemal organ found in the eyestalk) contain a factor that induces up to 100-fold increases in muscle cyclic GMP content, whereas extracts of other tissues are ineffective. This factor can also act on targets other than muscle, with hepatopancreas, testis, and neuronal tissue showing the largest responses. The sinus gland factor does not appear to affect cyclic GMP metabolism by depolarizing the preparation or by mobilizing extracellular Ca2+. The effect on cyclic GMP levels is dose-dependent and linear with time. Biological activity is destroyed by boiling and by 90% ethanol. It is also destroyed by trypsin, chymotrypsin, or pronase, which suggests that the factor is a protein or peptide. Both gel filtration chromatography and experiments using dialysis tubing with different molecular weight exclusion limits indicate that the factor has an apparent molecular weight of 5,000-12,000 daltons. A preliminary fractionation scheme, based on gel filtration, ion- exchange, and reverse-phase chromatography, gives greater than 1,300- fold purification. Our long-range goal is to purify this factor to homogeneity, compare it to other peptide hormones, and use it as a probe to evaluate the role of cyclic GMP at the neuromuscular junction.
Grasso, F. W., Dale, J. H., Consi, T. R., Mountain, D. C., and Atema, J. (1997). Effectiveness of continuous bilateral sampling for robot chemotaxis in a turbulent odor plume: Implications for lobster chemo-orientation. Biological Bulletin 193, 215-216.
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Gross, P. S., and Knowlton, R. E. (1999). Variation in larval size after eyestalk ablation in larvae of the snapping shrimp Alpheus heterochaelis. Journal of Crustacean Biology 19, 8-13.
The effect of eyestalk ablation at various times on size (overall body length, carapace length, and body width) of fourth instar (postlarval instar during normal development) Alpheus heterochaelis was studied. Animals which underwent bilateral eyestalk ablation earlier in larval life grew to a significantly larger overall size compared to unablated controls and larvae ablated later. This growth was manifested as lengthening of the abdomen and was not expressed in the cephalothorax. The relationship between total body length attained and time of ablation was greatest among larvae ablated during Stage III with overall size decreasing as time of ablation increased chronologically. The increase in overall size seen among larvae ablated progressively earlier may be a result of loss of hormonal control over hydromineral regulation and/or controlled manufacture and release of crustacean hyperglycemic hormone (CHH) by the X-organ-sinus gland, but it may also simply reflect a redirection of metabolic resources.
Grossfeld, R. M. (1975). Beta-alanine distribution in the lobster, Homarus americanus. Comp Biochem Physiol C 51, 1-4.
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Gu, P. L., and Chan, S. M. (1998). The shrimp hyperglycemic hormone-like neuropeptide is encoded by multiple copies of genes arranged in a cluster. Febs Letters 441, 397-403.
The crustacean hyperglycemic hormone (CHH) plays an important role in the regulation of glucose metabolism. We have cloned and sequenced several cDNAs encoding the preproCHH-like of the shrimp, Metapenaeus ensis. The preproCHH-like peptide of the shrimp consists of a signal peptide, a CHH precursor-like peptide (CPRP) and the CHH-like peptide, Comparative analysis revealed that the signal peptide and the CPRP of the shrimp peptide are the shortest among all the CHHs reported. MeCHH- like is expressed in the eyestalk, but it is not expressed in the heart, hepatopancreas, muscle, nerve cord and pre-hatch embryo. To study the structural organization of the shrimp CHH- like gene, we have screened the genomic DNA library constructed from one shrimp. Three groups of overlapping genomic clones have been isolated. The results from both genomic Southern blot analysis and library screening indicate that the shrimp genome contains at least six copies of the CHH-like genes arranged in a cluster on the chromosome. The size of the CHH-like genes is 1.5-2.1 kb, DNA sequence determinations indicate that the CHH- like genes share 98-100% amino acid sequence identity. There are three exons and two introns in each CHH-like gene, The first intron separates the signal peptide and the second intron separates the mature peptide in the coding region. The 150-200 bp of the upstream 5' flanking region of the CHH-like genes contains promoters with characteristics similar to most eukaryotic genes. Several putative cis-acting elements are also identified in the first 400 bp 5' end upstream region. The organization of the shrimp CHH-like genes is similar to that of the molt inhibiting hormone gene of the same shrimp and the crab, Charybdis feriatus. (C) 1998 Federation of European Biochemical Societies.
Guarino, A. M., Anderson, J. B., Pritchard, J. B., and Rall, D. P. (1976). Tissue distribution of (14C) methyl mercury in the lobster, Homarus americanus. J Toxicol Environ Health 2, 13-24.
[14C] Methyl mercury was administered by three different routes: intravascular (iv) injection, ingestion, and absorption from the ambient water. After iv administration (0.1 mg/kg) [14C] methyl mercury was rapidly removed from the plasma, followed by slow loss from the hepatopancreas and a strikingly persistent increase in the amount of radioactivity in the tail muscle. Most (80-90%) of the radioactivity in the hepatopancreas was shown by TLC methods to be the parent compound, and approximately 10% of this persisted for 6 days after injection. The half-life in this organ was found to be 21 days. One month after iv treatment with methyl mercury, the only organs that contained more than 0.1 ppm of this xenobiotic were egg masses, male gonads, heart, brain, intestine, and tail muscle. The half-lives for disappearance from sexual organs were greater than 1 month. After ingestion of [14C] methyl mercury (0.1 mg/kg) in food the hepatopancreas contained most of the administered dose at 6 days (68%), while the stomach (10%), tail muscle (8%), and carcass (15%) contained less. A unique distribution pattern emerged 6 days after exposure to [14C] methyl mercury- containing ambient water (0.1 ppm). The tail muscle contained most (50%) of the absorbed dose, whereas the hepatopancreas and carcass contained only 23 and 10%, respectively. In view of the small molecular size and high lipid solubility of methyl mercury and the lipophilic properties of the chitin-protein exoskeleton of the lobster, it is likely that significant uptake directly from the water as well as storage of absorbed methyl mercury occurred in the tail region. Residue analysis on untreated lobsters indicated that the egg masses contained the largest amount of methyl mercury (0.1 ppm). The hepatopancreas and carcass (muscle) levels were less than 0.05 ppm.
Guenther, C. M., and Atema, J. (1998). Distribution of setae on the Homarus americanus lateral antennular flagellum. Biological Bulletin 195, 182-183.
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Guillory, V., and Hein, S. (1998). A review and evaluation of escape rings in blue crab traps. Journal of Shellfish Research 17, 551-559.
Legislative and/or agency mandates for escape rings in blue crab (Callinectes sapidus) traps are increasing. Escape ring research and management regulations are reviewed. In general, escape rings in hard crab traps usually reduce sublegal catch without any accompanying loss in legal catch. Advantages and disadvantages of escape rings are listed and discussed. Percentage escapements by size group and sex through escape rings of various sizes were determined. Based on the criteria of maximizing sublegal crab escapement without an unacceptable loss of legal blue crabs, three 6.03-cm escape rings located on the vertical, outside walls of the upper chamber are recommended. An exemption is recommended for peeler traps to mitigate loss of peeler crabs to soft-shell crab shedders.
Haj, A., Clarke, S., Harrison, P., and Chang, E. (1996). In vivo muscle protein synthesis rates in the American lobster Homarus americanus during the moult cycle and in response to 20-hydroxyecdysone. J Exp Biol 199, 579-85.
Simultaneous measurements of in vivo rates of protein synthesis (Ks) in claw, leg and abdominal muscles were made in the American lobster Homarus americanus at three stages of the moult cycle. Ks values are significantly elevated during the premoult (stage D2-D3) and fall during the intermoult (stage C4) periods in all three muscles. Postmoult (stage A/B) levels are not significantly elevated above intermoult levels. Intermoult levels are between 0.3 and 0.4 % protein synthesized per day. In the premoult animals, the ribosomal activity (milligrams protein synthesized per microgram RNA per day) of the claw, abdominal and leg muscles is elevated three- to fivefold. The claw muscle maintains an elevated ribosomal activity into the postmoult stage whereas, by this stage, that of the other muscle tissues has fallen to intermoult levels. The RNA/protein ratios of the three muscle groups from intermoult, premoult and postmoult animals do not show any significant differences. 18S ribosomal RNA levels fluctuate slightly, with no consistent pattern over the moult cycle. In vivo injection of premoult concentrations of 20-hydroxyecdysone (20-HE) into intermoult lobsters results in elevated Ks values and ribosomal activity for the muscles after 3 days. RNA/protein ratios remain constant in the muscles in response to injections of 20-HE in vivo. In vitro preparations of leg muscle treated with 20-HE did not show similar elevated rates of protein synthesis.
Hamel, J. F., Ng, P. K. L., and Mercier, A. (1999). Life cycle of the pea crab Pinnotheres halingi sp nov., an obligate symbiont of the sea cucumber Holothuria scabra Jaeger. Ophelia 50, 149-175.
A new species of pea crab, Pinnotheres halingi sp. nov. (Pinnotheridae), found encysted in the right respiratory tree of the sea cucumber; Holothuria scabra (Holothuridea), from Solomon Islands, is described. The reproduction, infestation and pairing behaviour of the crabs were investigated through field observations and experiments. Infestation frequency in 8 monthly samplings of 25-30 holothurians was 98.6 +/- 2.6% in Kogu Halingi bay and 0% in two nearby sites. Of 403 pea crabs, 91.4% were found in pairs of opposite sex, 7.9% were single females and <1% were single males. The embryos developed on the female pleopods over ca. 30 days from fertilisation to the release of first zoeae and subsequently went through five pelagic zoeal stages. Infestation occurred at the megalops stage after about 59 days of development. A single pea;:rab (male or female) per host was found three months after larval infestation. Young males appeared to be strongly attracted to hosts that sheltered a single female, suggesting that pairing occurred as a male <6 mm carapace width joined a female. Larger crabs could not enter the host. Copulation was observed within the female cyst, preceding or overlapping oviposition. The male then progressed away from the female and from the anus, forming its own cyst along the way. Both larvae and small sub-adults invaded H. scabra with a minimum length of 80 mm, exclusively. P. halingi induced atrophy of the right respiratory tree of its host.
Han, K. K., Debuire, B., Dautrevaux, M., Biserte, G., Fattoum, A., Regnouf, F., Kassab, R., and Pradel, L. A. (1972). [Amino acid sequence of a fragment obtained by the cleavage of lobster (Homarus gammarus L.) arginine-kinase by cyanogen bromide]. C R Acad Sci Hebd Seances Acad Sci D 274, 324-6.
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Hanna, J. P., Grasso, F. W., and Atema, J. (1999). Temporal correlation between sensor pairs in different plume positions: A study of concentration information available to the American lobster, Homarus americanus, during chemotaxis. Biological Bulletin 197, 250-251.
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Haond, C., Flik, G., and Charmantier, G. (1998). Confocal laser scanning and electron microscopical studies on osmoregulatory epithelia in the branchial cavity of the lobster Homarus gammarus. Journal of Experimental Biology 201, 1817-1833.
The adult lobster Homaras gammarus is a weak hyper-regulator at low salinity. The objective of this study was to locate the ion-transporting tissues in the branchial chamber of this species, using electron microscopy and confocal laser scanning microscopy with a fluorescent vital stain for mitochondria, DASPMI, which is widely used to locate mitochondria-rich cells in ion-transporting epithelia of fish. A thick mitochondria- rich epithelium is present on the inner side of the branchiostegite and over the entire surface of the epipodites, Ultrastructural observations confirm that this tissue has features typical of an ion-transporting epithelium. When the lobster is transferred to low salinity, these epithelia undergo marked ultrastructural changes, such as an increase in thickness related to the development of basolateral infoldings, the appearance of numerous vesicles and an increase in height of the apical microvilli, In the gills, the branchial filaments are lined by a thin and poorly differentiated epithelium, containing numerous mitochondria; no significant ultrastructural changes were observed in the gills of animals acclimated to low salinity. In summary, in H, gammarus, no evidence of osmoregulatory structures was found in the gills. Differentiated ion-transporting epithelia are present in the branchial cavity, on the inner side of the branchiostegite and on the epipodites; these organs are probably involved in osmoregulation.
Haond, C., Bonnal, L., Sandeaux, R., Charmantier, G., and Trilles, J. P. (1999). Ontogeny of intracellular isosmotic regulation in the European lobster Homarus gammarus (L.). Physiological and Biochemical Zoology 72, 534-544.
Intracellular free amino acids were measured in the abdominal muscle of the three larval instars, postlarvae, and juveniles of the lobster Homarus gammarus, acclimated to seawater (35 parts per thousand) and to a dilute medium (22 parts per thousand), to study intracellular isosmotic regulation throughout the development of this species. Transfer to low salinity was followed by a highly significant drop of free amino acids level in all developmental stages. The main regulated amino acids were glycine, proline, and alanine. The level of regulation of total free amino acids changed at metamorphosis: the decrease in total free amino acids at low salinity was 46% in the three larval instars, but it was only 29% in postlarvae and 20% in juveniles. These results suggest that free amino acids, mainly glycine, proline, and alanine, are involved in intracellular isosmotic regulation in the lobster, with different levels of involvement in pre- and postmetamorphic stages. The ontogenetic changes in intracellular isosmotic regulation are discussed in relation to the changes in extracellular regulation (osmoregulation) in the lobster.
Harding, G. C., Kenechington, E. L., Bird, C. J., Pezzack, D. S., and Landry, D. C. (1997). Genetic relationships among subpopulations of the American lobster (Homarus americanus) as revealed by random amplified polymorphic DNA. Canadian Journal of Fisheries and Aquatic Sciences 54, 1762-1771.
Random amplified polymorphic DNA (RAPD) profiles were used in a preliminary investigation of the genetic relationships among American lobsters (Homarus americanus) from the ecologically disparate and geographically separate regions of the southern Gulf of St. Lawrence, a bay off southwestern Nova Scotia, and a deep-sea canyon off Georges Bank. Phenotypic analyses of the RAPD bands showed no significant difference between samples caught at these three geographic locations. Lobsters from the Gulf of Maine, collected inshore from Lobster Bay, Nova Scotia, and offshore from Georges Bank, were genetically the most similar (D = 0.002), whereas Gulf of St. Lawrence lobsters were about three times as genetically distant from these two subpopulations (D = 0.005-0.006). However, F-ST values at each RAPD band ranged from <0.000 to 0.073, indicating that lobsters at these three locations are not genetically isolated. The number of migrants needed to account for this observed level of genetic differentiation could be as few as five animals in each generation. The present findings should not have been surprising given the enormous potential for larval dispersal, the wide ranging movements of adult lobsters within each region, and the level of anthropogenic interference through both displacement of larvae and adults over the past century in the name of conservation, particularly adults released into the Gulf of Maine.
Harding, G. C., and Fraser, A. J. (1999). Application of the triacylglycerol/sterol condition index to the interpretation of larval lobster Homarus americanus distribution in close proximity to Georges Bank, Gulf of Maine. Marine Ecology-Progress Series 186, 239-254.
The triacylglycerol/sterol condition index was applied to larval lobster populations in the vicinity of Georges Bank in the Gulf of Maine. This index is related to larval size by an increasing power function which explains around 40 % of the variation. The poor fit can be explained by the uneven increase in triacylglycerol levels during development within each moult stage. Increased pigmentation is not related to larval condition, as measured by lipid storage, and masks the increased yellowish hue of lipids as development proceeds. The larval triacylglycerol/sterol index appears to undergo a diurnal cycle in Stage III and IV lobsters, with lowest values at midday and highest values after dark. This pattern cannot be explained by nocturnal feeding, which leaves the possibilities that satiated larvae descend below the surface metre during daylight and are therefore underrepresented in our collections by being more vertically diffuse, and/or that healthy well-fed larvae would be more likely to detect the trawl and escape during daylight. Few Stage I and II lobster larvae were found in the vicinity of Georges Bank with a condition index less than 0.1, which is the level laboratory studies indicate approaches the 'point-of-no-return'. The condition of all developmental stages was found to be better in individuals located off Georges Bank. This is not ecologically significant in the case of the first 2 stages because such a small proportion of the population was actually located off the bank. It is not resolved how the third and fourth stages arrive off Georges Bank, since shoal water hatching is the norm, but their lipid reserves are significantly greater than identical developmental stages located on the bank. Finally, the density of Stage IV larvae in the adjacent surface waters over the Gulf of Maine is twice that found over Georges Bank. This suggests that the lobster has evolved a life cycle in offshore waters in which larvae are hatched in shoal waters over the banks but the last 2 planktonic/pelagic stages either seek or are transported to, and by Stage IV thrive in, the warmer stratified layer over the deeper waters of the Gulf of Maine.
Harms, J. (1997). Biology of the lobster Homarus americanus - Factor,JR. Ethology 103, 700-700.
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Harrison, P., and el Haj, A. J. (1994). Actin mRNA levels and myofibrillar growth in leg muscles of the European lobster (Homarus gammarus) in response to passive stretch. Mol Mar Biol Biotechnol 3, 35-41.
An actin cDNA clone from the European lobster, Homarus gamarus, has been generated by RT-PCR and used as a probe to quantify the relative abundance of actin mRNA in lobster leg muscles following imposition of passive stretch by leg flexion. The sarcomere lengths of a population of fibers in the same muscles were measured to provide an indirect marker of myofibrillar growth. Stretch resulted in a 70% increase in actin mRNA levels compared with unstretched controls animals between weeks 1 and 2 after flexion of the legs. Sarcomere lengths increased by 23% immediately after imposition of the stretch. During the same period of observed increase in actin mRNA, the sarcomere lengths returned to their initial values, indicating that longitudinal growth of the myofibrils had occurred. Results are discussed in relation to the role of stretch in crustacean muscle growth during the moult.
Hartline, D. K. (1967). Impulse identification and axon mapping of the nine neurons in the cardiac ganglion of the lobster Homarus americanus. J Exp Biol 47, 327-40.
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Harzsch, S., Anger, K., and Dawirs, R. R. (1997). Immunocytochemical detection of acetylated alpha-tubulin and Drosophila synapsin in the embryonic crustacean nervous system. International Journal of Developmental Biology 41, 477-484.
The caridean shrimp Palaemonetes argentinus Nobili is well suited for studying developmental aspects of the crustacean nervous system due to its rapid embryonic development and short reproductive cycle. In the present paper, we demonstrate the pattern of central axonal pathways in embryos of this species by immunohistochemical detection of acetylated alpha-tubulin. Development of the neuropil was elucidated by using an antibody to a Drosophila synapsin. In the ventral nerve cord, the segmental axonal scaffold consists of the paired lateral connectives, a median connective, and the anterior and posterior commissures. Three nerve roots were found to branch off each ganglion anlage, i.e. the main segmental nerve root, a smaller posterior nerve and the intersegmental nerve. However, this pattern is different in the mandibular segment where no intersegmental nerve and only one commissure was encountered. The anterior part of the brain consists of a tritocerebral and a deutocerebral anlage as well as the anlage of the medial protocerebrum. The latter is connected to the eyestalk via the protocerebral tract. The sequence of development of the eyestalk ganglia was demonstrated in specimens which were stained with the anti-synapsin antibody. The medulla terminalis and medulla interna are the first neuropils to appear and are still fused in early stages. Later, the medulla interna splits off the medulla terminalis. The lamina ganglionaris is the last of the eyestalk neuropils to develop. These findings prove that immunocytochemistry against acetylated alpha-tubulin and synapsin are valuable tools for studying the development of the crustacean nervous system.
Harzsch, S., Miller, J., Benton, J., Dawirs, R. R., and Beltz, B. (1998). Neurogenesis in the thoracic neuromeres of two crustaceans with different types of metamorphic development. Journal of Experimental Biology 201, 2465-2479.
The mode of embryonic and larval development and the ethology of metamorphosis in the spider crab and the American lobster are very different, and we took advantage of this to compare neuronal development in the two species. The goals of this study were to discover whether the differences in the maturation of the neuromuscular system in the pereopods and the metamorphic changes of motor behavior between the two species are reflected at the level of the developing nervous system ('neurometamorphosis'). Furthermore, we wanted to broaden our understanding of the mechanisms that govern neuronal development in arthropods, Proliferation of neuronal stem cells in thoracic neuromeres 4-8 of the lobster Homarus americanus and the crab Hyas araneus was monitored over the course of embryonic and larval development using the in vivo incorporation of bromodeoxyuridine (BrdU). Neuropil structure was visualized using an antibody against Drosophila synapsin, While proliferation of neuronal precursors has ceased when embryogenesis is 80% complete (E80%) in the lobster thoracic neuromeres, proliferation of neuroblasts in the crab persists throughout embryonic development and into larval life, The divergent temporal patterns of neurogenesis in the two crustacean species can be correlated with differences in larval life style and in the degree of maturation of the thoracic legs during metamorphic development, Several unusual aspects of neurogenesis reported here distinguish these crustaceans from other arthropods, Lobsters apparently lack a postembryonic period of proliferation in the thoracic neuromeres despite the metamorphic remodeling that takes place in the larval stages. In contrast, an increase in mitotic activity towards the end of embryonic development is found in crabs, and neuroblast proliferation persists throughout the process of hatching into the larval stages, In both E20% lobster embryos and mid- embryonic crabs, expression of engrailed was found in a corresponding set of neurons and putative glial cells at the posterior neuromere border, suggesting that these cells have acquired similar specific identities and might, therefore, be homologous. None of the BrdU-labeled neuroblasts (typically 6-8 per hemineuromere over a long period of embryogenesis) was positive for engrailed at this and subsequent stages, Our findings are discussed in relation to the spatial and temporal patterns of neurogenesis in insects.
Harzsch, S., Benton, J., Dawirs, R. R., and Beltz, B. (1999). A new look at embryonic development of the visual system in decapod crustaceans: Neuropil formation, neurogenesis, and apoptotic cell death. Journal of Neurobiology 39, 294-306.
In recent years, comparing the structure and development of the central nervous system in crustaceans has provided new insights into the phylogenetic relationships of arthropods. Furthermore, the structural evolution of the compound eyes and optic ganglia of adult arthropods has been discussed, but it was not possible to compare the ontogeny of arthropod visual systems, owing to the lack of data on species other than insects. in the present report, we studied the development of the crustacean visual system by examining neurogenesis, neuropil formation, and apoptotic cell death in embryos of the American lobster, Homarus americanus, the spider crab, Hyas araneus, and the caridean shrimp, Palacmonetes argentinus, and compare these processes with those found in insects. Our results on the patterns of stem cell proliferation provide evidence that in decapod crustaceans and hemimetabolous insects, there exist considerable similarities in the mechanisms by which accretion of the compound eyes and growth of the optic lobes is achieved, suggesting an evolutionary conservation of these mechanisms. (C) 1999 John Wiley & Sons, Inc.
Harzsch, S., Miller, J., Benton, J., and Beltz, B. (1999). From embryo to adult: Persistent neurogenesis and apoptotic cell death shape the lobster deutocerebrum. Journal of Neuroscience 19, 3472-3485.
Neuronal plasticity and synaptic remodeling play important roles during the development of the invertebrate nervous system. In addition, structural neuroplasticity as a result of longterm environmental changes, behavioral modifications, age, and experience have been demonstrated in the brains of sexually mature insects. In adult vertebrates, persistent neurogenesis is found in the granule cell layer of the mammalian hippocampus and the subventricular zone, as well as in the telencephalon of songbirds, indicating that persistent neurogenesis, which is presumably related to plasticity and learning, may be an integral part of the normal biology of the mature brain. In decapod crustaceans, persistent neurogenesis among olfactory projection neurons is a common principle that shapes the adult brain, indicating a remarkable degree of life-long structural plasticity. The present study closes a gap in our knowledge of this phenomenon by describing the continuous cell proliferation and gradual displacement of proliferation domains in the central olfactory pathway of the American lobster Homarus americanus from early embryonic through larval and juvenile stages into adult life. Neurogenesis in the deutocerebrum was examined by the in vivo incorporation of bromodeoxyuridine, and development and structural maturation of the deutocerebral neuropils were studied using immunohistochemistry against Drosophila synapsin, The role of apoptotic cell death in shaping the developing deutocerebrum was studied using the terminal deoxynucleotidyl transferase-mediated biotinylated UTP nick end labeling method, combined with immunolabeling using an antiphospho histone H3 mitosis marker, Our results indicate that, in juvenile and adult lobsters, birth and death of olfactory interneurons occur in parallel, suggesting a turnover of these cells, When the persistent neurogenesis and concurrent death of interneurons in the central olfactory pathway of the crustacean brain are taken into account with the life-long turnover of olfactory receptor cells in crustacean antennules, a new, highly dynamic picture of olfaction in crustaceans emerges.
Hayashi, T., Hinssen, H., Cayer, M. L., and Smith, D. S. (1981). Organization of native and in vitro-reassembled myosin filaments from lobster tonic muscle. Tissue Cell 13, 35-44.
Tonic muscle of the crusher claw of the American lobster (Homarus americanus) was investigated with respect to sarcomeric organization and the capacity for self-assembly of extracted myosin for comparison with the same properties of rabbit muscle. Native myosin filaments in the lobster muscle are much longer than in rabbit skeletal fibers, and differ further in sarcomeric organization in showing an actin-to-myosin relationship in which two actin filaments are shared between adjacent myosins in a 12-membered orbital. The self-assembly of lobster myosin into filaments comparable in length and the fine structure to the natural filament was achieved in the presence of excess Mg2+, a condition not required for rabbit myosin self-assembly. Results of in situ and self-assembly studies indicate a difference in molecular organization between lobster and rabbit myosin filaments and of the inferred presence of regulatory factors in the formation of these ultrastructural elements. These studies represent the groundwork for an investigation of in vitro polymerization of actin in association with the synthetic lobster myosin filament.
Hayes, D., Huang, M., and Zobel, C. R. (1971). Electron microscope observations on thick filaments in striated muscle from the lobster Homarus americanus. J Ultrastruct Res 37, 17-30.
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Hedgecoco, D., Neslon, K., Simons, J., and Shleser, R. (1977). Genic similarity of American and European species of the lobster Homarus. Biol Bull 152, 41-50.
European lobsters (Homarus gammarus) from the Norway coast and from the Irish Sea are examined for electrophoretically detectable genetic variation in seventeen functionally different proteins. Forty-one loci encoding these proteins are homologous with loci studied in a previous survey of eight populations of H. americanus. Progeny hatched from ovigerous Norway females show variation in three enzymes, but Mendelian inheritance is confirmed only for triosephosphate isomerase and for one of the phosphoglucose isomerases. Complex PGI phenotypes are described. The average amounts of genetic variability in European and American lobster populations appear to be equivalent. More than one allele is detected at 20% of the loci, the average number of alleles detected per locus is 1.2 and the average proportion of loci heterozygous per individual is 4.0%. While much less genically variable than other invertebrates, Homarus is not atypical when compared with eleven decapod species that average 5.8% heterozygosity. This is consistent with hypotheses relating genetic variability to adaptive strategy. At thirty loci H. gammarus is monomorphic for the common H. americanus allele. Two acid phosphatase systems are fixed or nearly fixed for alternative alleles in the two species while the remaining polymorphic loci show various degrees of interspecific divergence. Unique H. gammarus alleles are detected at five loci but only contribute significantly to species differences at the Acph-5, Me, and Pgi-4 loci. Acph-1, Est-2, Pgi-3, and Pgm-1 are polymorphic for the same alleles in both species, but again, with various differences in allelic frequencies. In sum, average genetic identity and average genetic distance are: I = 0.896 +/- 0.007 and D = 0.110 +/- 0.007, respectively. Compared to the values for conspecific population comparisons, I = 0.994 +/- 0.001 and D - 0.006 +/- 0.001, it is clear that a small but significant amount of genetic divergence separates the European and American lobster. Based on the premise that protein differences between existing species reflect the amount of time since they shared a common ancestor, it can be speculated that the European and American lobsters were isolated during the Pleistocene. The apparent weakness of reproductive isolating barriers suggests that these populations have evolved allopatrically. Finally, quantification of species' genetic differences, together with recent successes in interspecific laboratory matings, implicates species hybridization as a potentially important breeding practice in lobster aquaculture.
Hedvall, O., Moksnes, P. O., and Pihl, L. (1998). Active habitat selection by megalopae and juvenile shore crabs Carcinus maenas: a laboratory study in an annular flume. Hydrobiologia 376, 89-100.
We studied megalopae (postlarvae) and young juveniles of the shore crab (Carcinus maenas L.) in laboratory experiments to examine four potentially important processes for juvenile distribution and recruitment: (1) hydrodynamic processes and passive deposition of megalopae, (2) active habitat selection of megalopae, (3) habitat specific predation rates, and (4) active habitat selection by juveniles. In an annular flume, simulating natural current velocities in nursery areas on the Swedish west coast, we assessed the distribution of dead megalopae, Live megalopae, live megalopae with predators (juvenile conspecifics and brown shrimp, Crangon crangon), and first instar crabs, in four simultaneously presented habitats: blue mussels (Mytilus edulis), eelgrass (Zostera marina), filamentous green algae (Cladophora sp. and Chaetomorpha linum) and bare sand. In a second experiment we studied the distribution of Live megalopae between four different ephemeral macroalgae with different structural complexity (Ulva lactuca, Enteromorpha sp., Cladophora sp. and Ectocarpus siliculosus). Dead megalopae were evenly distributed between the four habitats, whereas all other treatments showed significantly lower proportions of megalopae and juvenile crabs in the sand habitat (0-2%) compared to the structurally complex habitats (24-40%). The distribution between mussels, eelgrass and filamentous algae of live megalopae in absence of predators did not differ significantly from the hydrodynamical null hypothesis, i.e. distribution of dead megalopae. However, predation increased the proportion of megalopae significantly in the filamentous algae, providing the best refuge from predation of these habitats. First instar crabs showed a significantly different distribution compared to megalopae, with higher proportion in the algal habitat, whereas juvenile predatory crabs were found in significantly higher proportion among mussels. Megalopae selected all four different macroalgae species over open sand, but a significantly lower proportion were found in the algae with the highest structural complexity (Ectocarpus siliculosus; 14%) compared to the other algal species (26-30%). These results indicate that passive deposition have Little influence on the small scale (< 10 s of meters) distribution of shore crab megalopae during normal current velocities, but that active habitat selection by megalopae is the major process responsible for the non-random distribution of megalopae and juvenile shore crabs. The results further suggest that the initial distribution of megalopae between nursery habitats is quickly modified by habitat specific predation rates and size-specific movements and habitat choices by juveniles. The correlation between the habitat choice of megalopae and juvenile crabs, and the refuge value of the examined habitats suggests that habitat specific predation rates is a major selective force behind the behavior of active habitat selection in this species.
Heinrich, R., Cromarty, S. I., Horner, M., Edwards, D. H., and Kravitz, E. A. (1999). Autoinhibition of serotonin cells: An intrinsic regulatory mechanism sensitive to the pattern of usage of the cells. Proceedings of the National Academy of Sciences of the United States of America 96, 2473-2478.
After periods of high-frequency firing, the normal rhythmically active serotonin (5HT)-containing neurosecretory neurons of the lobster ventral nerve cord display a period of suppressed spike generation and reduced synaptic input that we refer to as "autoinhibition." The duration of this autoinhibition is directly related to the magnitude and duration of the current injection triggering the high-frequency firing, More interesting, however, is that the autoinhibition is inversely related to the initial firing frequency of these cells within their normal range of firing (0.5-3 Hz). This allows more active 5HT neurons to resume firing after shorter durations of inhibition than cells that initially fired at slower rates. Although superfused SHT inhibits the spontaneous firing of these cells, the persistence of autoinhibition in saline with no added calcium, in cadmium-containing saline, and in lobsters depleted of serotonin suggests that intrinsic membrane properties account for the autoinhibition. A similar autoinhibition is seen in spontaneously active octopamine neurons but is absent from spontaneously active gamma- aminobutyric acid cells. Thus, this might be a characteristic feature of amine-containing neurosecretory neurons. The 5HT cells of vertebrate brain nuclei share similarities in firing frequencies, spike shapes, and inhibition by 5HT with the lobster cells that were the focus of this study. However, the mechanism suggested to underlie autoinhibition in vertebrate neurons is that 5HT released from activated or neighboring cells acts back on inhibitory autoreceptors that are found on the dendrites and cell bodies of these neurons.
Helluy, S., Sandeman, R., Beltz, B., and Sandeman, D. (1993). Comparative brain ontogeny of the crayfish and clawed lobster: implications of direct and larval development. J Comp Neurol 335, 343-54.
The freshwater crayfish Cherax destructor and the lobster Homarus americanus have many similarities including life style, body form, and neural organization. However, the ontogenic history is very different in the two species. The development of Cherax is short and direct whereas the development of Homarus comprises three pelagic larval stages and takes more than twice as long from extrusion to benthic stages at constant temperature. In order to determine the progression of maturation of the nervous system in each species and the potential implications of pelagic forms on brain structure, the timing of appearance of 22 general and neural developmental events clearly identifiable in both species was compared. The onset of serotonin antigenicity in the different parts of the brain was chosen as one marker of neural development. During the first month of embryogenesis the timing of morphological, physiological, and neural events is similar in the two species. Morphological development is then accelerated in the crayfish near hatching time and over the two postembryonic stages before the advent of the independent benthic stage. Such heterochronic processes can at least partly account for the different developmental patterns in the two decapods. Among the characters showing similar timing in the two species is the formation of glomeruli (presumptive zones of synaptic contact) in the olfactory lobes of the deutocerebrum, although this event is embryonic in Homarus but postembryonic in Cherax. In contrast, glomerular formation in the accessory lobes is heterochronic: in both species, the glomeruli of the accessory lobes are acquired postembryonically, that is, 3 to 4 months earlier in Cherax than in Homarus. These data suggest that the development of the glomeruli in the olfactory lobes may depend primarily on internal developmental signals, whereas the triggering of glomerular formation in the accessory lobes may depend on external cues. The fact that, in Homarus, only the postlarval stages show mature accessory glomeruli may be a reflection of the functional requirements of benthic life.
Helluy, S. M., Ruchhoeft, M. L., and Beltz, B. S. (1995). Development of the olfactory and accessory lobes in the American lobster: an allometric analysis and its implications for the deutocerebral structure of decapods. J Comp Neurol 357, 433-45.
The allometric changes characterizing the growth of the deutocerebrum (midbrain) of the American lobster (Homarus americanus) are studied using computerized three-dimensional reconstructions of serial brain sections. During the embryogenesis of the midbrain, the paired accessory lobes (higher order processing areas) appear later than the paired olfactory lobes (primary olfactory centers), but the former grow faster from their emergence until metamorphosis. The accessory lobes, as they enlarge, shift progressively from a medial to a posterior position in the lateral deutocerebrum. In early juvenile stages the accessory lobes are one of the largest neuropils of the brain. However, these lobes stop growing in adult animals, whereas the brain and olfactory lobes continue to enlarge, albeit at a slow rate. The overall shape of the brain and the relative proportions and locations of the deutocerebral neuropils and associated cell clusters of various lobster ontogenetic stages are similar to those of selected adult decapods. In addition, the relation between deutocerebral organization and brain size seem parallel during lobster development and across crustacean species. Measurements of the brains of 13 species of decapods (illustrated in Sandeman et al. [1993] J. Exp. Zool. 265:112, plus Homarus) indicate the following trends: Small brains possess olfactory lobes but no accessory lobes, larger brains possess accessory lobes that are medial and small relative to the olfactory lobes, and the largest brains contain relatively voluminous posterior accessory lobes. These observations indicate that some differences in the organization of the deutocerebrum are related to absolute brain size in crustaceans and suggest that ontogenetic scaling of proportions may apply to the deutocerebral neuropils of decapods. Peramorphosis and paedomorphosis in the evolution of the decapod brain are considered.
Helluy, S. M., Benton, J. L., Langworthy, K. A., Ruchhoeft, M. L., and Beltz, B. S. (1996). Glomerular organization in developing olfactory and accessory lobes of American lobsters: stabilization of numbers and increase in size after metamorphosis. J Neurobiol 29, 459-72.
Olfactory glomeruli are columnar and radially arranged at the periphery of the primary chemosensory areas, the olfactory lobes (OLs), in the American lobster Homarus americanus. The number of olfactory glomeruli reaches nearly 100/lobe in midembryonic life, increases rapidly during larval life, and stabilizes at about 200 in juvenile and adult lobsters. The accessory lobes (ALs), higher order integration areas, are composed of cortical columns and of spherical glomeruli. Two populations of spherical glomeruli are defined, the cortical glomeruli located at the bases of the columns, and the medullary glomeruli scattered throughout the ALs. Both cortical columns and spherical glomeruli are seen for the first time in the second larval stage. There are about 1000 cortical columns and 1700 glomeruli/AL in the postlarva and these numbers remain constant during the life of the lobster. In both OLs and ALs, it is the size of the interglomerular spaces and of the glomeruli themselves that increases. Therefore, the data suggest that in both OLs and ALs the glomeruli were already generated when the lobster metamorphoses (stage III to IV) and switches from a planktonic to a benthic existence, and that the new sensory neurons that are formed at each molt in the antennulae grow into existing olfactory glomeruli. Stability of the glomerular population in the primary olfactory centers, once the full complement of glomeruli is acquired, has also been reported in insects, fish, and mammals.
Herskovits, T. T., San George, R. C., and Erhunmwunsee, L. J. (1981). Light-scattering investigation of the subunit dissociation of Homarus americanus hemocyanin. Effects of salts and ureas. Biochemistry 20, 2580-7.
The subunit dissociation of the hemocyanin of the lobster, Homarus americanus, by the various salts of the Hofmeister series and the hydrophobic reagents of the urea-guanidinium chloride (GdmCl) class was investigated by laser light scattering molecular weight measurements. The dissociations of the hemocyanin dodecamers to hexamers by the various salts and the lower members of the urea series are found to be rapid and reversible, as predicted by the mass action law for monomer- dimer type of reactions. The salts are found to be very effective dissociating reagents with the unusual order of increasing effectiveness, Cl- less than Br- less than I- less than ClO4-, SCN-. The ureas and GdmCl are found to be relatively ineffective dissociating agents. In addition, the ureas show a decreasing order of effectiveness in going from urea to methyl-, ethyl-, and propylurea. This suggests that hydrophobic interactions are not the dominant stabilizing forces between the pairs of hexamers that form the dodecameric structure. Polar and ionic interactions appear to be the major stabilizing forces of the dodecameric structure. The use of equations derived for predicting the effects of dissociating reagents and salts on the structure of subunit proteins [Herskovits, T. T., & Ibanez, V. S. (1976) Biochemistry 15, 5715-5721] together with binding and Setschenow constants based on model amino acid data is found to give good account of the dissociation behavior observed with the salts, urea, and methylurea in the presence of calcium ion at both pH 7.8 and pH 9.5. The apparent number of amino acids at the contact areas of the hexamers, Napp, required to fit the dissociation data were found to be 24 +/- 8 at pH 7.8 and 23 +/- 4 at pH 9.5. However, because of the possible effects of molecular microheterogeneity, the estimates of amino acids at the contact areas must be viewed with caution, depending on further investigations.
Hill, R. H., and Govind, C. K. (1983). Fast and slow motoneurons with unique forms and activity patterns in lobster claws. J Comp Neurol 218, 327-33.
The form of the fast closer excitor (FCE) and the slow closer excitor (SCE) motoneurons to the closer muscle in the claw of the lobster Homarus americanus was determined by injecting cobalt chloride or Lucifer Yellow into their respective somata. Both neurons are monopolar with the single neurite rising vertically to the dorsal surface of the ganglion, then travelling along this surface to where it gives off its dendrites before entering the second nerve root as an axon. The FCE and SCE motoneurons, however, differ in their dendritic form in several respects. First, the FCE completely lacks an anterior dendritic field, which is well elaborated in the SCE. Second, the FCE has fewer large primary dendrites in its posterior field than the SCE. Third, the posterior dendritic field of the FCE is not as extensive as that of the SCE. Fourth, the axon of the FCE originates from one of the posterior primary dendrites while that of the SCE is an axial extension of its neurite. Thus the SCE has a more elaborate dendritic field than the FCE, which may account for its greater excitability. For instance, recordings from intact lobsters show that the SCE has a lower firing threshold and is active for longer periods of time and at higher frequencies than the FCE.
Hoekman, T. B., and Dettbarn, W. D. (1971). Electrophysiological characteristics of giant axons of the lobster Homarus americanus and their response to cholinergic compounds. Comp Gen Pharmacol 2, 99-105.
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Hokkanen, J. E. I., and DeMont, M. E. (1997). Complex dynamics in the heart of the lobster Homarus americanus. Canadian Journal of Zoology-Revue Canadienne De Zoologie 75, 746-754.
Nonlinear dynamics have been shown to be important in describing a large number of complex physiological systems. This work examined the dynamics of the relatively simple neurogenic heart of the lobster Homarus americanus. A non- invasive device was used to collect continuous data of spontaneous heart beats, and time series of consecutive beat- to-beat intervals were generated from these data. This study was concerned with dynamic changes in beat-to-beat intervals that were induced by external effects including changes in both the level of activity and body temperature. Two types of temperature changes, short term (acute) and long term (chronic), were examined. In both cases, decreasing the ambient temperature increased the mean interval length as well as the variation. The regression slope of the correlation between the mean and the variation was unique for each lobster. Variation around the mean included periodic components. Not only the magnitude of the variation but also its complexity were affected by temperature. Approximate entropy increased as temperature decreased, implying temperature dependence of the regularity of the beat-to-beat intervals. We suggest that future physiological studies focus on attempts to understand changes in the complexity of physiological processes.
Holwerda, D. A., and Vonk, H. J. (1973). Emulsifiers in the intestinal juice of crustacea. Isolation and nature of surface-active substances from Astacus leptodactylus Esch. and Homarus vulgaris L. Comp Biochem Physiol [B] 45, 51-8.
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Holzenburg, A., Jones, P. C., Franklin, T., Pali, T., Heimburg, T., Marsh, D., Findlay, J. B., and Finbow, M. E. (1993). Evidence for a common structure for a class of membrane channels. Eur J Biochem 213, 21-30.
Electron microscopic analysis of gap-junction-like structures isolated from an anthropod (Nephrops norvegicus) and composed of a 16-kDa polypeptide, show the functional unit to be a star-shaped hexamer of protein arranged around a central channel which runs perpendicular to the plane of the membrane. Estimations of the molecular volume carried out on an averaged projection are consistent with a subunit mass of 16- 18 kDa. Fourier transform infrared spectroscopy indicates a high alpha- helical content for the protein, supporting secondary-structure predictions of four transmembrane alpha helices/monomer. The averaged projection shows a close resemblance to a hexamer of the 16-kDa protein built on the basis of a four alpha-helical bundle [Finbow, M. E., Eliopoulos, E. E., Jackson, P. J., Keen, J. N., Meagher, L., Thompson, P., Jones, P. C. & Findlay, J. B. C. (1992) Protein Eng. 5, 7-15]. The reconstructed image is also similar to that obtained for gap-junction- like channels isolated from a related arthropod [Homarus americanus; Sikerwar, S. S., Downing, K. H. & Glaeser, R. M. (1991) J. Struct. Biol. 106, 255-263] whose protein content was unknown but which we demonstrate may be composed of a related 16-kDa protein. Previous studies have shown a high sequence identity of the Nephrops 16-kDa protein with the 16-kDa proteolipid subunit c of the vascular H(+)- ATPase, both of which in turn bear similarity to the 8-kDa proteolipid subunit of the F1F0-ATP synthase. Expression of cDNA coding for the Nephrops 16-kDa protein in Saccharomyces cerevisiae, in which the endogenous gene coding for the V-ATPase proteolipid has been inactivated, restores V-ATPase activity and cell growth.
Homola, E., and Chang, E. S. (1997). Methyl farnesoate: Crustacean juvenile hormone in search of functions. Comparative Biochemistry and Physiology B-Biochemistry & Molecular Biology 117, 347-356.
The sesquiterpenoid methyl farnesoate (MF) is synthesized by crustacean mandibular organs and is present in the hemolymph. The chemical structure of MF is nearly identical to that of insect juvenile hormone III, differing only by the absence of an epoxide group. The functions of MF in crustaceans have been elusive, in part because the mandibular organs of most species are difficult to ablate. However, three roles of MF have emerged from a growing body of literature. They are (a) stimulation of general protein synthesis; (b) promotion of the molt cycle; and (c) reproduction in both males and females. These functions are not universal; rather, they reflect the diversity of the crustaceans that have been studied to date. This review will synthesize aspects of what is known about MF in crustaceans and outline some current avenues of research. (C) 1997 Elsevier Science Inc.
Homola, E., and Chang, E. S. (1997). Distribution and regulation of esterases that hydrolyze methyl farnesoate in Homarus americanus and other crustaceans. Gen Comp Endocrinol 106, 62-72.
Ester hydrolysis of methyl farnesoate (MF) by crustacean tissue homogenates was measured using the substrate [3H]MF in a radiochemical partition assay. Tissues were obtained from the lobster Homarus americanus, penaeid shrimp Sicyonia ingentis, thalanassid shrimp Callianassa californiensis, sand crab Emerita analoga, and spider crab Pugettia producta. The greatest specific activities were recovered from the hepatopancreas (239 to 11,500 pmol MF/min-mg total protein). Hepatopancreatic homogenates of C. californiensis were significantly more active than homogenates from the other species. In the lobster, esterases that hydrolyze MF were associated with lipid storage (R) cells of the hepatopancreas. Enzyme activity of lobster larval homogenates increased 1.5-fold during the second stage of development. The rate of MF hydrolysis by esterases extracted from the juvenile lobster hepatopancreas could not be correlated with molt stage or sex and was not significantly influenced by eyestalk ablation, mandibular organ ablation, or MF injection.
Hooper, S. L. (1998). Transduction of temporal patterns by single neurons. Nature Neuroscience 1, 720-726.
As our ability to communicate by Morse code illustrates, nervous systems can produce motor outputs, and identify sensory inputs, based on temporal patterning alone. Although this ability is central to a wide range of sensory and motor tasks, the ways in which nervous systems represent temporal patterns are not well understood. I show here that individual neurons of the lobster pyloric network can integrate rhythmic patterned input over the long times (hundreds of milliseconds) characteristic of many behaviorally relevant patterns, and that their firing delays vary as a graded function of the pattern's temporal character. These neurons directly transduce temporal patterns into a neural code, and constitute a novel biological substrate for temporal pattern detection and production. The combined activities of several such neurons can encode simple rhythmic patterns, and I provide a model illustrating how this could be achieved.
Horner, M., Weiger, W. A., Edwards, D. H., and Kravitz, E. A. (1997). Excitation of identified serotonergic neurons by escape command neurons in lobsters. Journal of Experimental Biology 200, 2017-2033.
Serotonin-containing neurosecretory neurons in the first abdominal ganglion (Al 5-HT cells) of the lobster (Homarus americanus) ventral nerve cord have been shown previously to function as 'gain setters' in postural, slow muscle, command neuron circuitries, Here we show that these same amine neurons receive excitatory input from lateral (LG) and medial (MG) giant axons, which are major interneurons in phasic, fast muscle systems, Activation of either LG or MG axons elicits short-latency, non-fatiguing, long-lasting excitatory postsynaptic potentials (EPSPs) in Al 5-HT cells which follow stimulus frequencies of up to 100 Hz in a 1:I fashion. Single spikes triggered in either giant axon can produce EPSPs in the Al 5-HT cells of sufficient magnitude to cause the cells to spike and to fire additional action potentials after variable latencies; action potentials elicited in this way reset the endogenous spontaneous spiking rhythm of the Al 5-HT neurons, The giant-axon-evoked EPSP amplitudes show substantial variation from animal to animal, In individual preparations, the variation of EPSP size from stimulus to stimulus was small over the first 25 ms of the response, but increased considerably in the later, plateau phase of each response, When tested in the same preparation, EPSPs in Al 5-HT cells evoked by firing the LG axons were larger, longer-lasting and more variable than those triggered by firing the MGs, Firing Al 5-HT cells through an intracellular electrode, prior to activation of the giant fiber pathway, significantly reduced the size of LG-evoked EPSPs in Al 5-HT cells, Finally, morphological and physiological results suggest that similarities exist between giant fiber pathways in lobsters and crayfish, The possible functional significance of an involvement of these large amine- containing neurosecretory neurons in both tonic and phasic muscle circuitries will be discussed.
Hovingh, P., and Linker, A. (1982). An unusual heparan sulfate isolated from lobsters (Homarus americanus). J Biol Chem 257, 9840-4.
An unusual heparan sulfate was isolated from lobsters (Homarus americanus). The polysaccharide has a composition and properties intermediate to heparin and the more common heparan sulfates. The sulfate and D-glucuronic acid content is high, while anticoagulant activity is low. The major repeating unit appears to consist of D- glucuronic acid and D-glucosamine N-O-disulfate. Some N-acetyl groups are present, the content of L-iduronic acid O-sulfate is low, and monosulfated or nonsulfated disaccharide-repeating units (very common in heparan sulfates) appear to be very rare. The data obtained again emphasize the heterogeneity of heparan sulfates and the need for adequate characterization when dealing with unusual or unexplored sources.
Howell, W. H., Watson, W. H., and Jury, S. H. (1999). Skewed sex ratio in an estuarine lobster (Homarus americanus) population. Journal of Shellfish Research 18, 193-201.
A total of 19,485 lobsters were caught at eight sites in the estuarine and coastal waters of New Hampshire from 1989 to 1992, and their size and sex were determined; The sex ratio of lobsters caught farthest from the coast, in Great Bay, was heavily skewed in favor in males. Sex ratios in other estuarine and river sir:es were also skewed toward males, and there was a tendency for the number of males per female to decline as one moved down the estuary toward the coast, where the sex ratio was nearly 1:1. The single offshore site was dominated by females, with about 0.6 males for each female. There were also seasonal trends in the sex ratios in the upper estuarine sites, where the number of males per female tended to decline from summer through autumn. In general, differences in the sex ratios between sites were those of primarily adult lobsters larger than 80 mm carapace length (CL). At all sites, the sex ratio of lobsters smaller than this size was close to 1:1, whereas in the upper estuary the mean sex ratio of lobsters greater than 80 mm CL was more than 14:1. These data, in conjunction with seasonal variations of sex ratios, suggest that differential movements of adult male and female lobsters is the primary cause of skewed sex ratios in the Great Bay Estuary.
Huber, R., and Kravitz, E. A. (1995). A quantitative analysis of agonistic behavior in juvenile American lobsters (Homarus americanus L.). Brain Behav Evol 46, 72-83.
In these studies a quantitative analysis of agonistic (fighting) behavior in lobsters in presented as a first step in our attempt to relate patterns of behavior to underlying neurobiological mechanisms. The agonistic behavior of juvenile American lobsters (Homarus americanus L.) was studied in laboratory tanks at the New England Aquarium. Using video analyses and statistical techniques: (1) an ethogram of agonistic behavior was constructed; and (2) the temporal structure of the behavior was identified. We demonstrated that fighting in juvenile lobsters proceeds according to strict rules of conduct. All animals exhibit six common behavioral patterns in a stereotypical manner. A temporal sequence of these patterns was evident, representing an increase in intensity during confrontations. The typical scenario of an encounter begins with extensive threat displays upon first contact, continues with periods of ritualized aggression and restrained use of the claws, and terminates in a brief session of unrestrained combat. Predictions of game theory (i.e. assessment strategies) provide a useful framework for the understanding of fighting in lobsters. The presence of a highly structured behavioral system may reduce the potential for damage in fights among conspecifics, and may prove useful in attempts to study the neurobiological causes of complex behavioral patterns such as aggression.
Huber, R., Orzeszyna, M., Pokorny, N., and Kravitz, E. A. (1997). Biogenic amines and aggression: Experimental approaches in crustaceans. Brain Behavior and Evolution 50, 60-68.
This review summarizes om experimental approaches attempting to link amines and their metabolites to aggression in crustaceans. The results demonstrate (i) that agonistic behavior in crustaceans can be quantified, (ii) that the amines themselves have telling and subtle effects on the fighting behavior of animals, (iii) that pharmacological interventions are possible that might allow a biochemical dissection of the underlying mechanisms involved in processes like decision making in these animals, and (iv) that selective metabolites of amines are excreted in the urine of lobsters where they may serve behavioral roles. Many of the studies presented here are preliminary. Nonetheless, we believe the results are provocative and nicely complement previous detailed physiological, morphological and biochemical studies exploring the roles of amines in aggression in crustaceans. We expect that the continued use of this invertebrate model system will allow us to gain considerable insight into, and understanding of, the role served by biogenic amines in a complex behavioral process like aggression.
Huberman, A., Aguilar, M. B., Brew, K., Shabanowitz, J., and Hunt, D. F. (1993). Primary structure of the major isomorph of the crustacean hyperglycemic hormone (CHH-I) from the sinus gland of the Mexican crayfish Procambarus bouvieri (Ortmann): interspecies comparison. Peptides 14, 7-16.
The amino acid sequence of this neuropeptide was elucidated by means of a combined approach of enzymatic digestions, manual and automatic Edman degradations, and mass spectrometry. It is a 72 residue peptide (molecular mass 8388 Da), with six cysteines forming three disulfide bridges connecting residues 7-43, 23-39, and 26-52, with blocked N- and C-termini, and lacking the amino acids histidine, methionine, and tryptophan. The CHH-I of Procambarus bouvieri is compared with the other known CHHs from Orconectes limosus (98.6% identity), Homarus americanus isomorph A (83.3% identity), Homarus americanus isomorph B (79.2% identity), and Carcinus maenas (61.1% identity).
Hubler, R., Fertl, B., Hellmann, N., and Decker, H. (1998). On the stability of the 24-meric hemocyanin from Eurypelma californicum. Biochimica Et Biophysica Acta-Protein Structure and Molecular Enzymology 1383, 327-339.
The stability of the 24-meric hemocyanin from Eurypelma californicum towards various denaturants (GdnHCl, urea, urea derivatives and salts of the Hofmeister series) indicates that the quaternary structure is stabilized by hydrophilic and polar forces. Thus, the interaction between the seven different subunit types of this cheliceratan hemocyanin is comparable with that of the closely related crustacean hemocyanins. In contrast, no significant influence of divalent ions such as Ca2+ and Mg2+ on the stability is observed at pH 8.0 and pH 8.5 but not at pH 7.0. Studies, both in the presence of urea and GdnHCl indicate that the denaturation process consists of a dissociation of the oligomeric structure into intact subunits at lower concentrations of denaturants followed by denaturation of the subunits at higher concentrations of denaturants. No intermediates such as hexamers or dodecamers were detected after 24 h of incubation. This study also reveals that oligomerization has a stabilizing effect on the heterogeneous subunits. In addition, differences in the primary structures result in different stabilities of the seven different subunit types. (C) 1998 Elsevier Science B.V.
Hufnagle, L. C., Camarata, S. E., Ernest, D., Krone, C. A., Chan, S. L., and Krahn, M. M. (1999). Development and application of a high-performance liquid chromatography screening method for aromatic compounds in invertebrate tissues. Archives of Environmental Contamination and Toxicology 37, 220-226.
Contamination of marine invertebrates by aromatic compounds (ACs) can occur from a variety of environmental. sources, bath natural and anthropogenic. Invertebrate species bioaccumulate ACs because they metabolize and eliminate them at a much slower rate than do vertebrates, such as fish. We have developed a high-performance liquid chromatography (HPLC) UV fluorescence screening method that measures ACs in invertebrate tissues. Screening methods have proven to be useful in response to environmental emergencies (e.g., oil spills) and in environmental monitoring because they are more rapid and less expensive than detailed analyses. This method was validated using three species of bivalves and lobster hepatopancreas and tail muscle as test samples. The AC screening method at naphthalene, phenanthrene, and benzo[a]pyrene wavelength pairs showed good correlation to GC/MS results. The method was also used successfully in response to the North Cape oil spill, off Narragansett, Rhode Island.
Hunt, H. L., and Scheibling, R. E. (1997). Role of early post-settlement mortality in recruitment of benthic marine invertebrates. Marine Ecology-Progress Series 155, 269-301.
Newly settled invertebrates usually are subject to high rates of mortality (Type ill survivorship). Therefore, knowledge of early post-settlement events is critical in determining if and when patterns of abundance and distribution of juveniles reflect settlement patterns. Causes of mortality of early juvenile invertebrates include delay of metamorphosis, biological disturbance, physical disturbance and hydrodynamics, physiological stress, predation, and competition. Predation is the best documented cause of early mortality, particularly for mobile species. Other possible causes which have not yet been investigated are developmental abnormalities, insufficient energy reserves, disease and. parasitism. In most studies of sessile invertebrates, early post-settlement mortality did not obscure the relationship between recruit and settler abundance. This relationship appears to be more variable among mobile species for which migration also can modify the distribution of settlers. There is still insufficient data to support general conclusions about the conditions under which recruitment rate can be predicted from settlement rate. Studies have found evidence of the effects of both settlement and early post- settlement mortality on the distribution of some sessile species at small spatial scales, but mortality appears to have less influence at larger scales. Much of the present knowledge of the early postsettlement period has come from studies of barnacles and ascidians and more information is needed for other groups of benthic marine invertebrates, particularly mobile species. The relative importance of mortality during the early post-settlement period compared to other life history stages can only be determined in studies which examine several stages.
Iconomidou, V. A., Willis, J. H., and Hamodrakas, S. J. (1999). Is beta-pleated sheet the molecular conformation which dictates formation of helicoidal cuticle? Insect Biochemistry and Molecular Biology 29, 285-292.
Over 100 sequences for cuticular proteins are now available, but there have been no formal analyses of how these sequences might contribute to the helicoidal architecture of cuticle or to the interaction of these proteins with chitin. A secondary structure prediction scheme (Hamodrakas, S.J., 1988. A protein secondary structure prediction scheme for the IBM PC and compatibles. CABIOS 4, 473-477) that combines six different algorithms predicting alpha-helix, beta-strands and beta- turn/loops/coil has been used to predict the secondary structure of chorion proteins and experimental confirmation has established its utility (Hamodrakas, S.J., 1992, Molecular architecture of helicoidal proteinaceous eggshells. In: Case, S.T. (Ed.), Results and Problems in Cell Differentiation, Vol. 19, Berlin-Heidelberg, Springer Verlag, pp. 116-186 and references therein). We have used this same scheme with eight cuticular protein sequences associated with hard cuticles and nineteen from soft cuticles. Secondary structure predictions were restricted to a conserved 68 amino acid region that begins with a preponderance of hydrophilic residues and ends with a 33 amino acid consensus region first identified by Rebers and Riddiford (Rebers, J.F., Riddiford, L.M., 1988. Structure and expression of a Manduca sexta larval cuticle gene homologous to Drosophila cuticle genes, J. Mol. Biol, 203, 411-423), Both classes of sequences showed a preponderance of beta-pleated sheet, with four distinct strands in the proteins from 'hard' cuticles and three from 'soft'. In both cases, tyrosine and phenylalanine were found on one face within a sheet, an optimal location for interaction with chitin. We propose that this beta-sheet dictates formation of helicoidal cuticle. (C) 1999 Elsevier Science Ltd. All rights reserved.
Incze, L. S., Wahle, R. A., and Cobb, J. S. (1997). Quantitative relationships between postlarval production and benthic recruitment in lobsters, Homarus americanus. Marine and Freshwater Research 48, 729-743.
Relationships between lobster postlarval supply and benthic recruitment were evaluated within and between oceanographically distinct segments of the range of the American lobster. Postlarvae (PL) were sampled by neuston nets in western Rhode Island Sound and the western Gulf of Maine, USA, from June to September 1989-95. Benthic lobsters were sampled in sublittoral cobble habitat by using a diver-operated airlift at the end of the settlement season. Average annual recruitment densities of young-of-year (YOY) lobsters ranged from 0.3 to 1.7 m(-2). YOY recruitment was positively correlated between areas. Integrated seasonal abundance of postlarvae was often much greater in Rhode Island than Maine, but production estimates (PL 1000 m(- 2) season(-1)), calculated from moult cycle stages and temperature-dependent growth rates, differed by a factor of <0.5. PL production was positively correlated between areas and explained greater than or equal to 81% of the annual variation in recruitment in each area and 90% for the two areas combined. In Maine, among-site differences in YOY recruitment persisted for a year after settlement and then began to lessen, at least in part because larger individuals moved into areas of initially lower recruitment.
Inoue, Y., Ueno, M., and Baba, S. (1997). Arterial system of the gill of the lobster, Homarus americanus. Journal of Morphology 233, 165-181.
Three-dimensional architecture of the branchial artery and venous vasculature of Homarus americanus was studied by the method of corrosion cast or styrene cracking and by scanning electron microscopy. Four arteries, the epibranchial (EA) and hypobranchial arteries (HA) on the septal wall of the afferent and efferent vessels, respectively, and two lateral canal arteries (LCA), each in one of the paired lateral canals, run parallel to the gill axis. The EA directs dendroid branches to the spongy tissue in the afferent vessel wall far from the efferent, supplying oxygen to the otherwise oxygen-depleted tissue. The HA distributes the filament arteriole (FA) into the central channel of individual middle filaments via the LCA. The FA opens halfway at a position where the channel narrows. Thus, it is likely that venous hemolymph in the central channel flows from base to tip in the direction in which arterial hemolymph from the FA flows. This and the anatomy of venous vasculature suggest three probable patterns of perfusion from afferent to efferent vessels: double serial circulation via the outer and inner filaments and novel routes both through the middle filament, i.e., single circulation via the afferent and efferent channels of this filament and double serial circulation via the outer filament and then the central channel of the middle. On the basis of the physics of flow and known physiological data, we propose that switching of these routes that involves independently functional multiple double serial circulations can play an important role in controlling efficiency of gas exchange, particularly during hypoxia. (C) 1997 Wiley-Liss, Inc.
Jaffe, H., Loeb, M., Hayes, D. K., Talbot, N., and Garvick, S. (1984). Isolation of crustacean erythrophore concentrating hormone from nerve tissue of Homarus americanus. Comp Biochem Physiol C 78, 397-401.
Crustacean erythrophore concentrating hormone (CECH) was isolated from lobster (Homarus americanus) eyestalks by reverse phase high- performance liquid chromatography (rp-hplc). Putative lobster CECH fractions co-chromatographed with commercially available pure CECH on two independent rp-hplc systems, and were positive for activity by bioassay. CECH was detected in eyestalk, but not brain homogenates.
Jahromi, S. S., and Atwood, H. L. (1969). Correlation of structure, speed of contraction, and total tension in fast and slow abdominal muscle fibers of the lobster (Homarus americanus). J Exp Zool 171, 25-38.
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James, M. O., and Barron, M. G. (1988). Disposition of sulfadimethoxine in the lobster (Homarus americanus). Vet Hum Toxicol 30, 36-40.
The long-acting sulfonamide antibacterial, sulfadimethoxine, has the potential for use in pen-held lobsters, Homarus americanus for treatment of gaffkemia. We evaluated the disposition of sulfadimethoxine after intrapericardial, oral or multiple oral administration of unlabelled or radiolabelled sulfadimethoxine (42 mg/kg) to 500 g lobsters. Elimination of parent sulfadimethoxine from hemolymph was very slow compared with elimination of the drug from blood of vertebrate species; the beta phase half-life was 77 hr in lobster as opposed to 7-40 hr in several vertebrate species. The pharmacokinetics of sulfadimethoxine after intrapericardial administration were linear up to 55 mg/kg, and binding of sulfadimethoxine to hemolymph proteins was constant over the range 14- 200 micrograms/ml. During the first week after dosing, concentrations of sulfadimethoxine and metabolites (total radioactivity) were similar in all non-excretory tissues, such that muscle, shell and hemolymph contained the largest percentage of the administered dose. By 2 weeks and later, hepatopancreas and digestive tract contained the highest concentration and percentage of the dose, by total radioactivity. Part of the dose of sulfadimethoxine was excreted unchanged in urine and part was metabolized in hepatopancreas to unknown polar metabolites. The major vertebrate metabolite, N-acetylsulfadimethoxine, was a very minor metabolite in lobster. Although sulfadimethoxine was extensively metabolized in hepatopancreas, the polar metabolites were very slowly excreted, suggesting inefficient excretion mechanisms for elimination of polar xenobiotic metabolites in the lobster.
James, M. O., Schell, J. D., Barron, M. G., and Li, C. L. (1991). Rapid, dose-dependent elimination of phenol across the gills, and slow elimination of phenyl sulfate in the urine of phenol-dosed lobsters, Homarus americanus. Drug Metab Dispos 19, 536-42.
Although lobsters are known to metabolize lipophilic organic compounds by monooxygenation, little is known of the fate of the hydroxylated metabolites. Single doses of [14C]phenol, 0.019 to 2.8 mg/kg, were administered intrapericardially to groups of lobsters. Hemolymph was sampled serially from appendage joints and analyzed for radioactivity and chemical composition. Separate groups of lobsters were dissected at 0.5, 4, and 24 hr after the 0.1-mg/kg dose to collect urine and tissue samples. Tank water was collected at 0.5 hr and analyzed. Phenol concentrations decreased rapidly in hemolymph (alpha t1/2 = 8.7 min, beta t1/2 = 14.0 min) and part of the dose was excreted through gills into tank water as parent phenol in the first 30 min. The percentage of each dose excreted through the gills increased with increasing dose up to greater than 90% at greater than 2 mg/kg. The phenol that was not excreted through gills was rapidly conjugated with sulfate in the antennal glands and possibly other sites. In both male and female lobsters, phenyl sulfate was eliminated from hemolymph much more slowly than parent phenol. The terminal elimination half-life of phenyl sulfate was slower in females (t1/2 = 11.9 hr) than in males (t1/2 = 6.3 hr). The [14C] present in urine collected 24 hr after the dose consisted primarily of phenyl sulfate (greater than 97%) with traces of phenyl beta-D-glucoside (0.1-3%). Thus, in the lobster, metabolism of phenol to polar conjugates did not enhance elimination from the animal.
James, M. O., Altman, A. H., Li, C. L., and Schell, J. D., Jr. (1995). Biotransformation, hepatopancreas DNA binding and pharmacokinetics of benzo[a]pyrene after oral and parenteral administration to the American lobster, Homarus americanus. Chem Biol Interact 95, 141-60.
It has been shown that American lobsters, (Homarus americanus) environmentally exposed to polycyclic aromatic hydrocarbons do not develop tumors or neoplastic changes although finfish exposed under identical conditions do develop cancer. In this study, environmentally relevant doses (nominally 50 micrograms/kg) of a radiolabelled model procarcinogen, benzo[a]pyrene (BaP), were administered i.v. or p.o. to lobsters and the fate of the radiolabel examined. Parent BaP was rapidly distributed from hemolymph into tissues after i.v. administration. Following oral administration, hemolymph concentrations of BaP rose slowly and reached levels similar to those found after i.v. administration by 48 h after the dose. The tissue distribution of BaP residues was determined at 3 days, 2 weeks and 4 weeks after the p.o. dose and 2 weeks after the i.v. dose. There was no route-related difference in tissue concentrations of BaP residues at 2 weeks. At all times, most of the retained BaP residues were in hepatopancreas (25-75% administered dose) or muscle (8-42% administered dose). Greater than 93% of the radioactivity in muscle was parent BaP at all studied times and the mean concentration of BaP residues in muscle was constant over the period of study. Although most of the radioactivity in hepatopancreas was BaP, metabolites were found and BaP residues declined with time. DNA isolated from hepatopancreas showed extremely low levels of BaP-metabolite binding, 0.016 +/- 0.013 pmol BaP equivalents/mg DNA, mean +/- S.D., n = 11. These studies show that BaP from dietary sources is retained for long periods by edible lobster tissues and suggest that a major reason for the resistance of American lobsters to polycyclic aromatic hydrocarbon-induced cancers is the very slow phase 1 metabolism to reactive metabolites.
James, M. O., and Boyle, S. M. (1998). Cytochromes P450 in crustacea. Comparative Biochemistry and Physiology C-Pharmacology Toxicology & Endocrinology 121, 157-172.
Since the last review of this topic, further insight has been gained into the presence and functions of cytochrome P450 proteins in the hepatopancreas and other organs of aquatic crustacean species, although progress has been slow relative to the advances in other species. Recent studies with several lobster, shrimp, crab and crayfish species suggest that cytochromes P450 in the 2 and 3 families are the most abundant forms in hepatopancreas microsomes. Substrates normally metabolized by CYP2 and CYP3 family members are monooxygenated more rapidly by crustacea than substrates normally metabolized by CYP1 family enzymes, e.g. erythromycin, testosterone and aminopyrine are much more rapidly monooxygenated than ethoxyresorufin. Some progress has been made in cloning and sequencing crustacean P450 forms. CYP2L1 and CYP2L2 cDNA sequences have been cloned from spiny lobster hepatopancreas libraries, and there was evidence for at least two more cytochromes P450 in spiny lobster hepatopancreas. An area of continued interest, but of no consensus or general findings, relates to the presence and inducibility of CYP1 family members in crustacea; Some studies indicate weak induction of total cytochrome P450 and increased turnover of substrates normally associated with CYP1, while others show no effect of the classic inducers that act at the Ah receptor in vertebrates. A few studies of the roles of cytochromes P450 in the biosynthesis and degradation of steroids, including ecdysteroids, have been published. Further studies are needed to understand the regulation and normal function of the crustacean cytochromes P450. (C) 1998 Elsevier Science Inc. All rights reserved.
James-Pirri, M. J., and Cobb, J. S. (1997). Growth rates of planktonic and newly settled American lobsters Homarus americanus. Marine Ecology-Progress Series 160, 233-240.
Growth rates, as estimated by the RNA:DNA ratio, were determined for planktonic post larvae and for recaptured and wild newly settled benthic stages (fifth and sixth instars) of the American lobster Homarus americanus. The mean growth rate of planktonic postlarvae in 1994 was 0.522 +/- 0.247 mg protein d(-1). This was significantly higher than planktonic growth rates observed in 1991 (0.449 +/- 0.121 mg protein d(-1)) but not in 1992 (0.460 +/- 0.144 mg protein d(-1)). The percentage of poorly nourished planktonic postlarvae, those with growth rates <0.220 mg protein d(-1), ranged from 3 to 13 % in 1991, 1992 and 1994 and was similar to that observed in previous years (1988 to 1990). Newly settled lobsters had significantly lower mean growth rates (0.223 +/- 0.180 mg protein d(-1)) than planktonic postlarvae. Recaptured lobsters originating from wild stock had significantly higher growth rates than those originating from laboratory stock (0.281 +/- 0.176 vs 0.085 +/- 0.078 mg protein d(-1), respectively). Laboratory rearing effects (lowered growth rates) appeared to persist even after 1 wk in the field. The differences in the growth rates between planktonic and benthic phase lobsters may be evidence of a tradeoff between slow growth due to decreased food ingestion and potential increased vulnerability to predation when actively foraging.
James-Pirri, M. J., Cobb, J. S., and Wahle, R. A. (1998). Influence of settlement time and size on postsettlement growth in the American lobster (Homarus americanus). Canadian Journal of Fisheries and Aquatic Sciences 55, 2436-2446.
We investigated the size and timing of settlement of postlarval (fourth instar) American lobster (Homarus americanus) and the size attained by the end of the first growing season. Mean size and duration of benthic instars (IV-XI) were obtained from a field growth experiment. Lobsters settling in early- and mid- season were larger at each instar and had different growth profiles than late-season settlers. In particular, the rate of growth at the fifth and sixth instar transition was greater for early- and mid-season settlers than for late-season settlers. Postlarvae settling early reached the ninth instar sooner than mid- or late-season settlers. Estimates of size and intermolt duration of each instar for early- and late-season postlarvae were applied to planktonic postlarval data (1988-1995) to estimate growth trajectories during the first year. For all years, postlarvae present early in the season were 30-50% larger (carapace length) and two or three instars further developed than late settlers by the end of the growing season. Estimates of size attained by the end of the 1994 growing season matched field-collected benthic size frequency data for this same year. Although initial carapace length at settlement was important, the timing of settlement was more influential on the size attained by the end of the first growing season.
James-Pirri, M. J., and Cobb, J. S. (1999). Behavioral interactions of postlarval and fifth instar lobsters (Homarus americanus) in a simulated cobble environment. Marine and Freshwater Behaviour and Physiology 32, 207-222.
Behavioral interactions among newly settled postlarval and fifth instar lobsters in a simulated cobble environment were quantified. Seven behavioral categories were identified and the proportion of time spent in each was evaluated. Transition matrices for three general behavior categories were evaluated for the postlarval and fifth instar. Postlarval and fifth instar lobsters displayed different behavioral patterns. Postlarvae spent a large proportion of time walking on the sand substrate and excavating shelters, whereas fifth instar lobsters spent the majority of time excavating and sitting in shelters. Agonistic interactions between early benthic stage lobsters were similar to those described for older juvenile and adult lobsters. Dominance hierarchies, burrow invasion and eviction of subdominant individuals were observed in both the postlarval and fifth instar.
James-Pirri, M. J., and Cobb, J. S. (1999). Influence of coded micro-wire tags on postlarval lobster (Homarus americanus) behavior. Marine and Freshwater Behaviour and Physiology 32, 255-259.
The influence of coded micro-wire tags on postlarval lobster behavior was investigated in a simulated cobble environment. Newly settled postlarvae were divided into two treatment groups, tagged and untagged. Seven behavioral categories were identified and the proportion of time spent in each for each treatment was evaluated. We observed no difference in the proportion of time spent in any of the behaviors between tagged and untagged postlarvae. We conclude that the presence of micro-wire tags does not influence behavior of newly settled lobsters.
Jennings, J. B., and Gelder, S. R. (1976). Observations on the feeding mechanism, diet and digestive physiology of Histriobdella homari Van Beneden 1858: an aberrant polychaete symbiotic with North American and European lobsters. Biol Bull 151, 487-517.
1. The aberrant annelid Histriobdella homari (Polychaeta:Eunicida) lives in the branchial chambers of the marine lobsters Homarus americanus and H. vulgaris where it feeds on the rich microflora of bacteria, blue-green algae and related organisms which grow on the inner surface of the branchial chamber, the setae fringing the edges of the carapace, the gill filaments and, especially, the surfaces and setae of the epipodite plates between the gills. H. homari, therefore, is to be regarded as an epizoic microphagous cleaning symbiote of the lobsters. 2. The alimentary canal consists of mouth, buccal cavity, oesophagus, proventriculus, stomach, intestine and anus. The much- modified proboscis lies ventrally below the oesophagus and proventriculus, with its anterior portions protruding into the rear of the buccal cavity. 3. The proboscis consists of two fixed parallel mandibles, a transverse carrier which slides upon the mandibles and to which is attached, posteriorly, a median flexible dorsal rod and, anteriorly, four pairs of movable articulated maxillae, paired external and internal retractor muscles and various tensor, flexor and extensor muscles. 4. Contraction of the retractor muscles withdraws the carrier and maxillae posteriorly, causing bowing of the dorsal rod which is fixed at its posterior end. Relaxation of the muscles allows the rod to straighten and, thus, causes protraction of the carrier and protraction and lateral expansion of the maxillae. Contraction and relaxation of the relaxation of the retractor muscles are supplemented by appropriate changes in the other muscular components of the proboscis. 5. During feeding the serrated anterior ends of the mandibles are applied to the food, the maxillae are fully expanded and then dawn ventro-posteriorly toward the mid-line by contraction of the retractor muscles in the effective movement of the feeding mechanism. This draws the food organisms across the anterior ends of the mandibles, detaching them from the substratum and allowing their ingestion by ciliary action. The first pair of maxillae are also capable of independent action and can be used while the remainder of the proboscis apparatus is held in the protracted position. 6. Detached microorganisms are entangled in a sticky mucous secretion from the salivary glands; other salivary secretions provide a transport medium for the clumped particles and a third set contain C-esterases which initiate digestion. 7. Ingested food is held briefly in the proventriculus, then passed to the stomach where gland cells secrete A- and C-esterases which continue and extend the digestion initiated by the salivary C-esterases. 8. Some soluble products of gastric digestion are taken up by absorptive cells in the stomach wall and their digestion is completed intracellularly by enzymes which include beta-glucuronidase. Others pass into the intestine for absorption and completion of digestion by cells similar to the gastric absorptive cells but which lack beta-glucuronidase...
Jensen, G. C., and Asplen, M. K. (1998). Omnivory in the diet of juvenile dungeness crab, Cancer magister Dana. Journal of Experimental Marine Biology and Ecology 226, 175-182.
Juvenile Dungeness crab (Cancer magister Dana) have always been considered strict carnivores; however, early instars have been observed ingesting filamentous, epiphytic diatoms in the field. To investigate the potential importance of diatoms in the diet of this species, wild-caught megalopae were raised to the third juvenile instar on a variety of dietary treatments. Although the animals that were fed only filamentous diatoms (Melosira sp. and Grammatophora sp.) had intermolt periods 20-25% longer than those raised on mussel (Mytilus sp.) flesh or a mix of diatoms and mussels, there was no difference in molt size increment between the treatments. This ability to utilize such alternative food resources at a lower trophic level may be especially important in years of high settlement into coastal estuaries, when large numbers of juvenile crab are known to cause dramatic reductions in prey densities. (C) 1998 Elsevier Science B.V.
Jivoff, P., and Hines, A. H. (1998). Effect of female molt stage and sex ratio ion courtship behavior of the blue crab Callinectes sapidus. Marine Biology 131, 533-542.
In many species, males and females actively participate in courtship, and the outcome of pre-mating interactions influences the mating success of both sexes, Female blue crabs, Callinectes sapidus, mate soon after their final molt to maturity. thus female molt stage dictates the timing of mating. In a field experiment, we manipulated female molt stage and sex ratio to test their effects on the courtship behavior of both sexes. if female behavior influences the behavior and pairing success of males, and if male courtship influences male pairing-success. Early-molt-stage females avoided males during courtship, whereas late-molt-stage females sought out males. As a result, males had to pursue and capture early-molt-stage females whereas males displayed to late-molt-stage females and more easily physically controlled them, Males sometimes abandoned late-molt-stage females. but this occurred more often when females were abundant. The rate at which females avoided males was positively correlated with that of males abandoning females. and males that were unsuccessful at pairing met with higher rates of female resistance than successful males, suggesting that female behavior influences male pairing- success. Unlike unsuccessful males. successful males more often made the transition between display and maintaining physical control of the female. At high male sex ratios, males initiated courtship more readily: thus both sexual competition and female behavior influence male courtship in this species.
Jivoff, P., and Hines, A. H. (1998). Female behaviour, sexual competition and mate guarding in the blue crab, Callinectes sapidus. Animal Behaviour 55, 589-603.
Blue crabs mate immediately after the female's final moult. We tested the influence of female moult stage, sex ratio and male size on the pre-mating behaviour of both sexes, and the ability of males to pair with females and aggressively compete for access to females. We observed crabs in field enclosures and surveyed pre-copulatory mate-guarding patterns in the field. Female behaviour changed as they progressed through the final moult cycle, such that early moult-stage females avoided males, but late moult-stage females initiated pair formation. The changes in female behaviour influenced both the behaviour and pairing capability of males. Males courted and paired with late moult-stage females on their first attempt, but pursued early moult-stage females because their first attempts to pair often failed. In the field, early moult-stage females were paired less often than late moult-stage females. The pre-mating behaviour of both sexes also varied with sex ratio; when males were abundant, males traded courtship for forced capture and females courted less. Large males were more successful at take- overs, but did not pair more often with late moult-stage females, suggesting that large males do not consistently guard for less time than small males. The changes in female behaviour are consistent with the female's need to avoid the costs of guarding and suggest that females influence how pre-copulatory mate guarding occurs in this species. (C) 1998 The Association for the Study of Animal Behaviour.
Johansson, A. S., and Schreiner, B. (1965). Neurosecretory cells in the ventral ganglia of the lobster, Homarus vulgaris L. Gen Comp Endocrinol 5, 558-67.
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Johnson, M. W., and Gentile, J. H. (1979). Acute toxicity of cadmium, copper, and mercury to larval American lobster Homarus americanus. Bull Environ Contam Toxicol 22, 258-64.
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Johnson, B. R., and Atema, J. (1983). Narrow-spectrum chemoreceptor cells in the antennules of the American lobster, Homarus americanus. Neurosci Lett 41, 145-50.
The present study shows that smell (antennular) receptor cells are as narrowly tuned to single compounds as taste (leg) receptor cells in the lobster. Antennular receptors responded best to hydroxy-L-proline (57% of the 30 cells sampled) and taurine (24%). In the presence of 14 other compounds in equimolar concentrations, the hydroxy-L-proline and taurine receptors showed a suppressed response to their best stimulus. Other cells had best responses to ammonium chloride, betaine, L- glutamate or L-proline. The results have implications for molecular receptor processes and for the neural basis of feeding behavior.
Johnston, D. J., and Alexander, C. G. (1999). Functional morphology of the mouthparts and alimentary tract of the slipper lobster Thenus orientalis (Decapoda : Scyllaridae). Marine and Freshwater Research 50, 213-223.
The mouthparts and proventriculus of Thenus orientalis Lund are adapted to ingest soft flesh, which is consistent with the diet of this and other scyllarids. The crista dentata are reduced, with food transfer into the oesophagus facilitated by large stout setae on the second and third maxillipeds. The mandibles exert little force and most food maceration is effected by the gastric mill. Ingestion is aided by mucus secreted by rosette glands in the paragnaths and membranous lobe, as well as expansion of four longitudinal folds in the oesophageal wall. The cardiac stomach has considerable food storage capacity by extension of its membranous walls, reduced ossicles and simplified ventral filtration channels. The filtering ability of the pyloric filter press is consistent with other macrophagous decapods. The dorsal caecum above the pyloric stomach has an absorptive columnar epithelium that contains acid mucin granules and protein. Muscular walls and longitudinal folds in the hindgut facilitate faecal pellet extrusion.
Jorge-Rivera, J. C., and Marder, E. (1997). Allatostatin decreases stomatogastric neuromuscular transmission in the crab Cancer borealis. Journal of Experimental Biology 200, 2937-2946.
The effects of insect allatostatins (ASTs) 1-4 were studied on the stomach musculature of the crab Cancer borealis. Of these, Diploptera-allatostatin 3 (D-AST-3) was the most effective. D- AST-3 (10(-6) mol l(-1)) reduced the amplitude of nerve-evoked contractions, excitatory junctional potentials and excitatory junctional currents at both cholinergic and glutamatergic neuromuscular junctions. Muscle fiber responses to ionophoretic applications of both acetylcholine and glutamate were reduced by the peptide, but D-AST-3 produced no apparent change in the input resistance of the muscle fiber. D-AST-3 reduced the amplitude of muscle contractures evoked by both acetylcholine and glutamate, but had no effect on contractures induced by a high [K+]. These data suggest that D-AST-3 decreases the postsynaptic actions of both neurally released acetylcholine and glutamate, Because an AST-like peptide is found in peripheral sensory neurons that innervate stomatogastric muscles and in the pericardial organs, we suggest that an AST- like peptide may play a role in controlling the gain of the excitatory neuromuscular junctions in the stomach.
Jorstad, K. E., and Farestveit, E. (1999). Population genetic structure of lobster (Homarus gammarus) in Norway, and implications for enhancement and sea-ranching operation. Aquaculture 173, 447-457.
Lobster stock enhancement in Norway is based on selection of wild broodstock and artificial production of juveniles which are released into the natural environment. Four enzymes (malic enzyme, phosphoglucomutase (two loci), isocitrate dehydrogenase and glucosephosphate isomerase) were used to screen genetic variation in 22 different populations (about 2580 individuals) along the coast. Minor but statistically significant variation in allele frequencies was found for all five loci. The sample collected from the most northern and isolated population, in Tysfjord, was polymorphic for only a single locus and contributed substantially to the overall sample heterogeneity. Except in some pairwise tests, no significant variation was found when testing the samples within the Skagerak and Vestland regions. The samples collected in the More-Trondelag region show significant variation for one locus (PGM-2*), which were confirmed in pairwise tests for genetic differentiation. Future activities aiming on local stock enhancement should evaluate the risk for unwanted genetic impacts. Commercial ranching operations of lobster, including selective breeding, should be carried out only in areas with low levels of genetic differentiation. (C) 1999 Elsevier Science B.V, All rights reserved.
Ju, S. J., Secor, D. H., and Harvey, H. R. (1999). Use of extractable lipofuscin for age determination of blue crab Callinectes sapidus. Marine Ecology-Progress Series 185, 171-179.
The blue crab Callinectes sapidus is an economically and ecologically important species in many temperate estuaries, yet stock assessments have been limited to length-based methods for demographic analyses. We evaluated the potential of age pigments (lipofuscins) sequestered in neural tissue of eye- stalks and brains to estimate the age of blue crabs collected from Chesapeake Bay and Chincoteague Bay. The rate of lipofuscin accumulation was determined using crabs of known age reared in the laboratory. Age pigments were extracted from neural tissues (eye-stalk or brain), quantified, and normalized to protein content to allow comparisons across tissue types and crab sizes. Field-collected blue crabs (35 to 185 mm carapace width) contained highly variable levels of age pigments (coefficient of variation = 58%). Lipofuscin level was significantly related to carapace width, but not significantly different between gender or sampling location. In juveniles (40 to 70 mm carapace width) reared for 6 mo, the age pigments showed no significant change during the rapid summer growth period, but significantly increased during fall (after 3 mo). Lipofuscin contents in known-age reared crabs were positively related to chronological age. Modal analysis of lipofuscin for field-collected adult males provided separation of multiple modes, whereas carapace width showed only a single broad mode. These results confirm the potential use of lipofuscin for age estimation of blue crabs.
Juorio, A. V., and Sloley, B. D. (1988). The presence of tyramine and related monoamines in the nerve cord and some other tissues of the lobster, Homarus americanus. Brain Res 444, 380-2.
This report shows the existence of endogenous p-tyramine in the nerve cord and some organs of the lobster. Their concentrations are lower than those of dopamine or 5-hydroxytryptamine. The nerve cord levels of m-tyramine, beta-phenylethylamine and tryptamine are much lower than those of the phenolic or catecholic amines. The finding that the administration of an aromatic-L-amino acid decarboxylase inhibitor leads to a decrease of p-tyramine gives further evidence that this amine is synthesized from p-tyrosine, which is also found in high concentrations in the lobster nerve cord. The widespread distribution of p-tyramine in the nervous system and peripheral tissues of the lobster suggests that this amine may have additional roles rather than functioning only as a precursor of p-octopamine.
Kaloustian, H. D., and Kaplan, N. O. (1969). Lactate dehydrogenase of lobster (Homarus americanus) tail muscle. II. Kinetics and regulatory properties. J Biol Chem 244, 2902-10.
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Kaloustian, H. D., Stolzenbach, F. E., Everse, J., and Kaplan, N. O. (1969). Lactate dehydrogenase of lobster (Homarus americanus) tail muscle. I. Physical and chemical properties. J Biol Chem 244, 2891-901.
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Karavanich, C., and Atema, J. (1998). Individual recognition and memory in lobster dominance. Animal Behaviour 56, 1553-1560.
American lobsters, Homarus americanus, form stable dominance relationships in captivity. Size, sex and stage in the moult cycle are important determinants for dominance. Other factors, such as recent agonistic experience play a role. This paper investigates how lobsters maintain their stable dominance relationships: they may recognize individuals or alternatively, recognize overall dominance status. We paired lobsters in two consecutive 'boxing matches'. Results indicate that lobsters remember familiar opponents when kept either in isolation or in communal tanks for 24 h between their first and second fights. Subordinates immediately backed away from familiar dominants, avoiding a second fight. In some animals, this memory lasted between 1-2 weeks if pairs were kept separate between the first and second fights. When paired for the second fight against unfamiliar dominant lobsters, subordinate lobsters from first fights actively fought and won the encounter. These results suggest that lobsters are capable of 'individual recognition'. In nature, the observed social organization of lobsters may be maintained by individual recognition of a small number of residents inhabiting separate, nearby shelters. (C) 1998 The Association for the Study of Animal Behaviour.
Karavanich, C., and Atema, J. (1998). Olfactory recognition of urine signals in dominance fights between male lobster, Homarus americanus. Behaviour 135, 719-730.
The maintenance of dominance hierarchies in the American lobster (Homarus americanus) is based on recognition of the dominant animal by the loser of a recent fight. it is hypothesized that chemical signals are the basis of this recognition. Adult male lobsters were paired for initial boxing matches between unfamiliar animals. The same pairs were re- matched for 3 more consecutive fights. In the first experiment, treatment animals had their primary olfactory receptor cells of the lateral and medial antennules lesioned before fights 2-4 and control animals received sham lesions. The durations of fights 2-4 for control pairs were significantly shorter than the durations of fights between lesioned animals. In the second experiment, male pairs were again allowed to establish a dominance relationship in a first fight. During second fights, urine release by both animals was prevented by the use of catheters in treatment animals while control pairs wore sham catheters. Again, durations of the second fights of control animals were significantly shorter than those of treatment animals. Together, these experiments indicate that urine- carried chemical signals, perceived by the antennules, reduce the duration and aggression of male dominance fights on subsequent days because the loser of the first fight backs off almost immediately when he smells the urine of the known dominant.
Katz, P. S., Kirk, M. D., and Govind, C. K. (1993). Facilitation and depression at different branches of the same motor axon: evidence for presynaptic differences in release. J Neurosci 13, 3075-89.
This study provides evidence that a neuron can exhibit differences in activity-dependent transmitter release at two synaptic sites due to variations in the properties of its presynaptic terminals. Two muscles in the stomatogastric system of the lobster Homarus americanus are innervated by a single motor neuron but respond differently to that motor neuron's input, resulting in two different movements evoked by one motor neuron. During continued motor neuron stimulation, the gm8 muscle contracts slowly and maintains contraction, while the gm9 muscle contracts rapidly and then relaxes. These different muscle responses can be accounted for, in large part, by the properties of the respective neuromuscular synapses: the excitatory junctional potentials recorded in gm8 are initially small but summate and facilitate with repeated stimulation, while those in gm9 are initially large but depress with repeated stimulation. Presynaptic differences in neurotransmitter release contribute strongly to the divergent responses; reduction of the excitatory junction potential amplitude by partial postsynaptic receptor blockade or by desensitization does not change the amount of depression at gm9. However, reduction of neurotransmitter release with low-Ca2+, high-Mg2+ saline removes gm9 synaptic depression and reveals that both neuromuscular junctions exhibit frequency-dependent homosynaptic facilitation. Postsynaptic differences in muscle input resistance and muscle composition may enhance the effects of the divergent release properties, but are not responsible for the activity-dependent changes. Ultrastructural features of the nerve terminals on the two muscles are consistent with the differential output of the terminals; the synapses on gm9 are larger and have more presynaptic dense bars than their counterparts on gm8. These data suggest that the basis for the differences in transmitter release between the two muscles may be a higher density of release sites in the gm9 synapses that leads to a higher output of neurotransmitter, rapid depletion of transmitter stores, and synaptic depression.
Keen, J. N., Caceres, I., Eliopoulos, E. E., Zagalsky, P. F., and Findlay, J. B. (1991). Complete sequence and model for the C1 subunit of the carotenoprotein, crustacyanin, and model for the dimer, beta-crustacyanin, formed from the C1 and A2 subunits with astaxanthin. Eur J Biochem 202, 31-40.
The complete sequence has been determined for the C1 subunit of crustacyanin, an astaxanthin-binding protein from the carapace of the lobster Homarus gammarus (L.). The polypeptide, 181 residues long, is similar (38% identity) to the other main subunit, A2 and to plasma retinol-binding protein. The tertiary structure of the C1 subunit has been modelled on that derived for the A2 subunit from the coordinates of retinol-binding protein. Residues lining the putative binding cavities and at the putative carotenoid binding sites of the two subunits are highly conserved. The carotenoid environments are characterized by a preponderance of aromatic and polar residues and the absence of charged side-chains. A tentative model for the dimer, beta- crustacyanin, formed between the two subunits with their associated carotenoid ligands, is discussed. The model is based on the crystal structure of the dimer of bilin-binding protein, a member of the same superfamily. This structure has enabled us to examine mechanisms for the bathochromic spectral shift of the protein-bound carotenoid and to identify likely contact regions between dimers in octameric alpha- crustacyanin.
Keen, J. N., Caceres, I., Eliopoulos, E. E., Zagalsky, P. F., and Findlay, J. B. (1991). Complete sequence and model for the A2 subunit of the carotenoid pigment complex, crustacyanin. Eur J Biochem 197, 407-17.
The complete sequence has been determined for the A2 subunit of crustacyanin, an astaxanthin-binding protein from the carapace of the lobster Homarus gammarus. The polypeptide chain is 174 residues long and is similar to proteins of the retinol-binding protein superfamily. Some regions of the sequence are most similar to the retinol-binding protein, beta-lactoglobulin subgroup, while the disulphide bonding pattern is more akin to that seen in the porphyrin binding proteins insecticyanin and bilin-binding protein. It is beginning to appear as though this superfamily of proteins, characterized by a similar gross structural framework, may be further subdivided into interrelated subclasses. Model building based on the coordinates of the known structure of human plasma retinol-binding protein and on empirical prediction algorithms has allowed the putative identification of side- chains which line the binding cavity. This pocket is larger than in retinol binding protein and beta-lactoglobulin but does not allow the carotenoid to adopt a folded conformation. The amino acid composition of the pocket does not support a 'charge-shift'-type hypothesis to support the bathochromic shift phenomenon which takes place on interaction of the chromophore with the protein. Instead aromatic side- chains may play a prominent role.
Kegel, G., Reichwein, B., Tensen, C. P., and Keller, R. (1991). Amino acid sequence of crustacean hyperglycemic hormone (CHH) from the crayfish, Orconectes limosus: emergence of a novel neuropeptide family. Peptides 12, 909-13.
The primary structure of the major form of CHH from sinus glands of the crayfish, Orconectes limosus, was determined by manual Edman microsequencing. It is a 72-residue peptide with a calculated Mr of 8400 Da. In the number of residues, it is identical to the CHH of Carcinus maenas and very similar to MIH (moult inhibiting hormone) of Homarus americanus. All three peptides have pGlu as N-terminus in common, and Val-NH2 is the C-terminal residue in Orconectes and Carcinus CHH. Six Cys residues occupy identical position in the three peptides. There is a 61% sequence identity with Carcinus CHH, and an 81% identity with Homarus MIH.
Khayat, M., Yang, W. J., Aida, K., Nagasawa, H., Tietz, A., Funkenstein, B., and Lubzens, E. (1998). Hyperglycaemic hormones inhibit protein and mRNA synthesis in in vitro-incubated ovarian fragments of the marine shrimp Penaeus semisulcatus. General and Comparative Endocrinology 110, 307-318.
The present work shows for the first time that peptides belonging to the Crustacean hyperglycaemic hormone family (CHH- family hormones) from Penaeus japonicus affect protein and mRNA synthesis in in vitro-incubated ovarian explant fragments removed from vitellogenic females of Penaeus semisulcatus. Reduced levels of protein synthesis, determined by TCA- precipitable S-35-labeled proteins, were found in the presence of crude sinus gland extracts from both P. semisulcatus and P. japonicus. A similar inhibitory effect compared to controls was found with each of the seven CHH-family peptides. Non-CHH- family peptides did not reduce protein synthesis. Crude sinus gland extracts prepared from Il semisulcatus were at least 20- fold more effective than sinus gland extracts of Il japonicus. The inhibition level was directly related to the concentration of the peptide in the incubation media, but its degree varied among the different tested peptides. The profile of proteins synthesized during in vitro incubation was analyzed using polyacrylamide gel electrophoresis under denatured and reduced conditions (SDS-PAGE), followed by autoradiography. Synthesis of several proteins was reduced, including proteins with electrophoretic mobility similar to that of vitellin. Immunoprecipitation with antiserum prepared against native ovarian vitellin confirmed the inhibitory effect of CHH-family peptides on vitellin synthesis. The crude sinus gland extract and CHH-family peptides also inhibited RNA synthesis, as determined by [H-3]uridine incorporation into mRNA of ovarian fragments. It is concluded that in addition to their role in carbohydrate metabolism, CHH-family peptides may also influence ovarian physiology in crustaceans. (C) 1998 Academic Press.
Khoo, J. G. I., and Sin, F. Y. T. (1999). Isolation and characterization of a novel peptide gene in the lobster Jasus edwardsii. Zoological Studies 38, 95-109.
Previous studies have demonstrated an immunological and functional relationship between vasopressins and the moult- inhibiting hormone (MIH) of crustaceans. Using primers derived from the rat vasopressin gene, 2 fragments were amplified from the genomic DNA of the lobster Jasus edwardsii. This paper describes the characterization of the 960-bp sequence. Northern blot analysis showed that the 960 bp sequence was expressed in the epithelia, eyestalk, heart, hepatopancreas, and muscle, but expression was most prominent in the eyestalk. In situ hybridization using the 960-bp sequence as a probe detected RNAs in the neurosecretory regions of the eyestalk. The expression of these genes appeared to be higher in the intermoult than the ecdysial eyestalk. Sequence analysis of the 960-bp PCR product revealed an intron/exon splice junction, a protein coding region with a stretch of repetitive sequences which is translated into a metallothionein-like protein. Furthermore, the 960-bp sequence also shared over 40% sequence homology to rat vasopressin, and MIH and CHH of some crustaceans. We called this sequence the Novel Peptide Sequence (NPS).
Killebrew, D. A., Brown, R., Duerr, J., and Ahearn, G. (1998). Molecular characterization of the lobster (Homarus americanus) NHE sodium/proton antiporter. Faseb Journal 12, 6036.
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Killian, K. A., and Page, C. H. (1992). Mechanosensory afferents innervating the swimmerets of the lobster. II. Afferents activated by hair deflection. J Comp Physiol [A] 170, 501-8.
Feathered hair sensilla fringe both rami of the lobster (Homarus americanus) swimmeret. The sensory response to hair displacement was characterized by recording afferent impulses extracellularly from the swimmeret sensory nerve while deflecting sensilla with a rigidly- coupled probe or controlled water movements. Two populations of hairs were observed: "distal" hairs localized to the distal 1/3 of each ramus and "proximal" hairs near its base. Distal hairs are not innervated by a mechanosensory neuron but instead act as levers producing strain within adjacent cuticle capable of activating a nearby hypodermal mechanoreceptor. Hair deflections of 25 degrees or more are required to evoke an afferent response and this response is dependent on hair deflection direction. The frequency and duration of the afferent discharge evoked are determined by the velocity of hair displacement. Each proximal hair is innervated by a single mechanosensory neuron responding phasically to hair deflections as small as 0.2 degrees in amplitude. Deflection at frequencies up to 5 Hz elicits a single action potential for each hair movement; at higher frequencies many deflections fail to evoke an afferent response. These sensilla, which are mechanically coupled, may be activated by the turbulent flow of water produced by the swimmerets during their characteristic beating movements.
Killian, K. A., and Page, C. H. (1992). Mechanosensory afferents innervating the swimmerets of the lobster. I. Afferents activated by cuticular deformation. J Comp Physiol [A] 170, 491-500.
The mechanosensory innervation of the lobster (Homarus americanus) swimmeret was examined by electrophysiologically recording afferent spike responses initiated by localized mechanical stimulation of the caudal surface of the swimmeret. Two functional groups of subcuticular hypodermal mechanoreceptors innervate the swimmeret. Afferents of one group innervate the small discrete "ridges" of calcified cuticle lining the margins of both swimmeret rami. Putative ridge receptors are bipolar sensory neurons responding phasically to deformation of the ridge cuticle with the number and frequency of impulses produced dependent on stimulus strength and velocity. Afferents of the second group, which innervate substantial areas of hypodermis underlying the soft, flexible cuticular regions of the swimmeret, were designated "wide-field" hypodermal mechanoreceptors. These neurons have multiterminal receptive fields and respond phaso-tonically to cuticular distortion. The response properties of both types of hypodermal mechanoreceptors imply that they are activated during the characteristic beating movements of the swimmerets.
Kilman, V., Fenelon, V. S., Richards, K. S., Thirumalai, V., Meyrand, P., and Marder, E. (1999). Sequential developmental acquisition of cotransmitters in identified sensory neurons of the stomatogastric nervous system of the lobsters, Homarus americanus and Homarus gammarus. Journal of Comparative Neurology 408, 318-334.
We studied the developmental acquisition of three of the cotransmitters found in the gastropyloric receptor (GPR) neurons of the stomatogastric nervous systems of the lobsters Homarus americanus and Homarus gammarus. By using wholemount immunocytochemistry and confocal microscopy, we examined the distribution of serotonin-like, allatostatin-like, and FLRFNH2- like immunoreactivities within the stomatogastric nervous system of embryonic, larval, juvenile, and adult animals. The GPR neurons are peripheral sensory neurons that send proprioceptive information to the stomatogastric and commissural ganglia. In H. americanus, GPR neurons of the adult contain serotonin-like, allatostatin-like. and Phe-Leu-Arg-Phe- amide (FLRFNH2)-like immunoreactivities. In the stomatogastric ganglion (STG) of the adult H. americanus and H. gammarus, all of the serotonin-like and allatostatin-like immunoreactivity colocalizes in neuropil processes that are derived exclusively from ramifications of the GPR neurons. In both species, FLRFNH2-like immunoreactivity was detected in the STG neuropil by 50% of embryonic development (E50). Allatostatin-like immunoreactivity was visible first in the STG at approximately E70-E80. In contrast, serotonin staining was not clearly visible until larval stage I (LI) in H. gammarus and until LII or LIII in H. americanus. These data indicate that there is a sequential acquisition of the cotransmitters of the GPR neurons. (C) 1999 Wiley-Liss, Inc.
Kimura, C., Ahearn, G., Busquets-Turner, L., Haley, S., Nagao, C., and Couet, H. (1994). IMMUNOLOCALIZATION OF AN ANTIGEN ASSOCIATED WITH THE INVERTEBRATE ELECTROGENIC 2Na+/1H+ ANTIPORTER. J Exp Biol 189, 85-104.
Epithelial plasma membranes from crustacean gut, kidney and gills have been shown recently to display an electrogenic 2Na+/1H+ antiporter that differs considerably in its physiological properties from the vertebrate electroneutral 1Na+/1H+ exchange paradigm. In this study, we describe the histological and cytological localization of an antigen associated with invertebrate electrogenic 2Na+/1H+ antiport in lobster (Homarus americanus) tissues using a monoclonal antibody (MAb 11) raised in mice against purified brush border membranes of the hepatopancreatic epithelium. Previous work showed that MAb 11 inhibited electrogenic 2Na+/1H+ and Ca2+/H+ exchange by hepatopancreatic brush border membrane vesicles, but was without effect on Na+-dependent d- glucose transport, suggesting a restricted inhibitory specificity to the cation exchanger. MAb 11 binding occurred at hepatopancreatic epithelial R-cell brush border membranes, at plasma membranes of the antennal gland and gill podocytes, and at vacuolar membranes of hepatopancreatic B- and R-cells, gill nephrocytes and epithelial cells of the antennal gland labyrinth and gill lamellae, as assessed by FITC- labelled secondary antibodies. Control FITC-labelled antibodies raised in mice against vertebrate keratin proteins displayed only weak non- specific binding to the tissues and cells responding intensely to MAb 11, supporting the specific nature of MAb 11 binding to its cognate antigen. The broad histological and cytological distribution of MAb 11 binding to plasma membranes and vacuolar membranes from several lobster organ systems suggests that the physiological activities regulated by its antigen, possibly an element of the invertebrate electrogenic cation exchanger, may be diverse.
King, T. L., Uthe, J. F., and Musial, C. J. (1993). Polycyclic aromatic hydrocarbons in the digestive glands of the American lobster, Homarus americanus, captured in the proximity of a coal-coking plant [published erratum appears in Bull Environ Contam Toxicol 1995 May;54(5):787]. Bull Environ Contam Toxicol 50, 907-14.
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King, T. L., Haines, B. K., and Uthe, J. F. (1996). Non-, mono-, and di-o-chlorobiphenyl concentrations and their toxic equivalents to 2,3,7,8-tetrachlorodibenzo[p]dioxin in Aroclors(R) and digestive glands from American lobster (Homarus americanus) captured in Atlantic Canada. Bull Environ Contam Toxicol 57, 465-72.
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Kirk, M. D., and Govind, C. K. (1983). Innervation and motor patterns of the abdominal superficial flexor muscles in larval lobsters. J Neurobiol 14, 399-405.
The pattern of innervation and motor program of the abdominal superficial flexor muscle was investigated electrophysiologically in larval lobsters (Homarus americanus). The muscle receives both excitatory and inhibitory innervation in the larval as well as in the embryonic stages. Individual muscle fibers receive a single inhibitory neuron (f5) and a maximum of three excitors. Based on spike heights these axons belong to either the small (f1 or f2) or large (f3, f4) motoneurons. While the small axons preferentially innervate the medial muscle fibers the large axons innervate medial as well as lateral fibers. This larval pattern of innervation resembles the pattern in the adult lobster. The resemblance extends to the firing patterns as well with both large and small excitors firing spontaneously. Furthermore, evoked activity in the larvae produces reciprocal (and occasionally cyclical) bursts of excitor and inhibitor neurons denoting abdominal extension and flexion and resembling the firing patterns in adults. Consequently motor programs employed in steering the pelagic larvae are reminiscent of the programs for maintaining posture in the benthic adult lobsters.
Kirk, M. D., and Govind, C. K. (1992). Early innervation of abdominal swimmeret muscles in developing lobsters. J Exp Zool 261, 298-309.
The swimmerets in the abdomen of the lobster Homarus americanus are paired external appendages whose back and forth propulsive movements are brought about largely by a group of power and return stroke muscles located in the lateral abdominal cavity. We find functional innervation of these muscles by several excitatory axons and a single inhibitor in embryonic and stage 1 larval lobsters before the external appendages are even formed. This early innervation is via a few nerve bundles in which branches of the motor axons are intertwined in a complex manner. As the swimmerets develop to maturity in later larval and juvenile stages, the innervation consisting usually of several excitor and a single inhibitor synaptic terminals becomes localized to individual muscles. Patterned synaptic activity in these muscles was not seen in the embryonic and larval stages but has been shown in early juvenile stages, when it coincides with the onset of rhythmic movement of the swimmerets. Consequently, such early innervation of the swimmeret muscles may be influential in establishing the central circuitry for the generation of patterned activity, a possibility that was discounted in a previous study (Proc. Natl. Acad. Sci. USA, 70:954-958).
Klapper, W., Kuhne, K., Singh, K. K., Heidorn, K., Parwaresch, R., and Krupp, G. (1998). Longevity of lobsters is linked to ubiquitous telomerase expression. Febs Letters 439, 143-146.
Mammals have high growth rates in embryonic and juvenile phases and no growth in adult and senescent phases. We analyzed telomerase activity in a fundamentally different animal which grows indeterminately. Lobsters (Homarus americanus) grow throughout their life and the occurrence of senescence is slow. A modified TRAP assay was developed and the lobster telomeric repeat sequence TTAGG was determined, We detected telomerase activities which were dependent on RNA and protein components, required dGTP, dATP and dTTP, but not dCTP. Telomerase products with a five nucleotide periodicity were generated. High telomerase activities were detected in all lobster organs. We conclude that telomerase activation is a conserved mechanism for maintaining long-term cell proliferation capacity and preventing senescence, not only in cellular models or embryonic life stages but also in adult multicellular organisms. (C) 1998 Federation of European Biochemical Societies.
Klein, M. J., and Ahearn, G. A. (1999). Calcium transport mechanisms of crustacean hepatopancreatic mitochondria. Journal of Experimental Zoology 283, 147-159.
Mechanisms of calcium transport across crustacean hepatopancreatic mitochondrial membranes were investigated in the Atlantic lobster, Homarus americanus. Hepatopancreatic mitochondria were purified by combining methods developed for isolation of these organelles from mammalian and crustacean tissues involving the incorporation of differential centrifugation and Percoll-gradient centrifugation. Enrichment of the preparation was assessed using purification of enzyme markers and electron microscopic examination. Pure hepatopancreatic mitochondria displayed Ca-45(2+) uptake by an apparent electrogenic, ruthenium red-inhibited (K-i = 1000 +/- 137 nM), transport process that was sensitive to cytoplasmic pH and heavy metals such as Zn2+. Ca-45(2+) efflux from mitochondria took place by an apparent diltiazem-inhibited, electroneutral, 2Na(+)/1Ca(2+) antiporter and an apparent diltiazem-insensitive 2H(+)/1Ca(2+) antiporter. One or both antiporters were capable of exchanging preloaded Ca-45(2+) for external Zn2+. The apparent uptake protein did not display saturation kinetics over the concentration range selected, but was specifically inhibited by ruthenium red, strongly suggesting the occurrence of a mammal-like uniporter protein in these crustacean mitochondria. These apparent uptake and efflux transport systems are discussed with regard to calcium storage during the molt cycle and the role they may play in heavy metal detoxification. J. Exp. Zool. 283:147-159, 1999. (C) 1999 Wiley-Liss, Inc.
Knowles, J. F., Smith, D. L., and Winpenny, K. (1998). A comparative study of the uptake, clearance and metabolism of technetium in lobster (Homarus gammarus) and edible crab (Cancer pagurus). Radiation Protection Dosimetry 75, 125-129.
Lobsters and edible crabs have been exposed to Tc-95(m) in, their sea water or in their food, and the uptake, retention and distribution of the isotope in their bodies examined. The steady-state concentration factor C-ss for uptake of 95Tc(m) from sea water was significantly greater for female crabs (C-ss =17.9) than for males (C-ss= 14.4). There was no such sex difference in lobsters and they took up Tc-95(m) to much higher levels with a C-ss of 1160. Retention of the isotope was similar for crabs and lobsters and for animals of both sexes. However the route of uptake was important with more rapid clearance after uptake from sea water (t(b)12 = 51 days) than after uptake from food (t(b)12 = 108 days). Technetium was found predominantly in the hepatopancreas of all crabs and most male lobsters. In a few male lobsters and all females it was mainly in muscle. Lobster ovaries consistently contained more activity than testes but this difference was not seen in crabs. Ar the subcellular level Tc-95(m) in hepatopancreas cells of both lobster and crab occurrred mainly in the cytosol. Results of initial studies into the relationships between technetium and cytosol proteins are given and the possible basis for the much greater accumulation of the element by lobsters than crabs discussed.
Knudsen, H., and Tveite, S. (1999). Survival and growth of juvenile lobster Homarus gammarus L. raised for stock enhancement within in situ cages. Aquaculture Research 30, 421-425.
The growth of juvenile lobster Homarus gammarus L. reared on sandy sediments under laboratory conditions was compared with the growth of lobsters reared within in situ cages in the wild. The caged lobsters, left without any attention or care for 3 months, achieved an average size similar to that attained under optimal laboratory conditions, (8.8 mm carapace length; CL). Growth was positively correlated to cage size and depth, Overall average survival was 66%, ranging from 0% to 90% for clusters of 30 individually caged juveniles.
Kobierski, L. A., Beltz, B. S., Trimmer, B. A., and Kravitz, E. A. (1987). FMRFamidelike peptides of Homarus americanus: distribution, immunocytochemical mapping, and ultrastructural localization in terminal varicosities. J Comp Neurol 266, 1-15.
The distribution of FMRFamidelike peptides was studied in the nervous system of the lobster Homarus americanus by using immunocytochemical and radioimmunological techniques. By radioimmunoassay FMRFamidelike immunoreactivity (FLI) was found in low levels (ca. 1 pmol/mg protein) throughout the ventral nerve cord and in much higher amounts (60-100 pmol/mg protein) in the neurosecretory pericardial organs. Immunocytochemical studies showed FLI in approximately 300-350 cell bodies, and in distinct neuropil regions, neuronal fiber tracts, and varicose endings. Specificity of the immunostaining was tested by preabsorbing the antiserum with FMRFamide, with peptides having similar carboxyl termini to FMRFamide (Met-enkephalin-Arg-Phe, Phe-Met-Arg-Tyr- amide), with several amidated peptides (alpha-melanocyte-stimulating hormone, substance P, oxytocin), and with proctolin, a peptide found widely distributed in the lobster nervous system. Of these substances, only FMRFamide blocked the staining. In addition to the pericardial organs, significant levels of FLI were found in neurosecretory regions associated with thoracic second roots and in the connective tissue sheath that surrounds the ventral nerve cord. In all three regions, immunocytochemical studies showed the FLI to be localized to fine fibers and associated terminal varicosities lying close to the surface of the tissue, with no obvious target in their immediate vicinity. When examined at the ultrastructural level, the immunoreactive varicosities of the thoracic second roots and of the ventral nerve cord sheaths were found a few microns from the surface of the tissue and contained electron-dense granules. In the immunoreactive nerve cord sheath endings, in addition to the large, dense granules, small, clear vesicles were found. The appearance and location of these terminals suggest a neurohormonal role for FMRFamidelike peptides in lobsters. The observation that low levels of FLI are found in the hemolymph supports this suggestion. In addition, the localization of FLI to particular neuronal somata, fiber tracts, and neuropil regions suggests possible functional roles for these peptides in (1) integration of visual and olfactory information, (2) function of the anterior and posterior gut, and (3) the control of exoskeletal muscles.
Koeller, P., and Crowell, G. (1998). Electrotaxis in American lobsters, Homarus americanus, and its potential use in sampling early benthic-phase animals. Fishery Bulletin 96, 628-632.
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Koeller, P. (1999). Influence of temperature and effort on lobster catches at different temporal and spatial scales and the implications for stock assessments. Fishery Bulletin 97, 62-70.
Correlation analysis was used to investigate how effort and temperature changes influence lobster catches at different spatial and temporal scales and how they may affect the use of catch statistics in stock assessments. At the largest scales examined (Atlantic coast of Nova Scotia, 50 yr), a significant correlation between catches and temperatures at short lags (0-3 yr) prior to 1974 suggests that catches were driven by temperature-induced changes in growth or lobster activity. However, changes in effort could not be ruled out as a cause of the observed cycles because sea surface temperatures may reflect weather conditions and the "fishability" of the grounds. Longer lags (6-8 yr) after 1974 are consistent with increased larval survival due to sharply rising temperatures and the "recruitment pulse" of the late 1980s. There was no clear relation between temperature and catches at intermediate scales (statistical districts, 10 yr), but effort changes indicate that catches alone do not accurately reflect changes in lobster abundance. At the smallest scale examined (distances between ports, days) correlations of both temperature and effort with catch in areas with similar coastal topographies indicated that the correlation between temperature and catch was not causative, i.e. changes in effort, were driven by wind events that were also influencing water temperatures. The results indicate that effort changes must be considered at all scales in stock assessments, but they become increasingly important at the smallest (i.e. <100 km, within years) scales. They also indicate that significant correlations between lobster catches and environmental parameters must be interpreted cautiously.
Kotak, V. C., and Page, C. H. (1986). Tactile stimulation of the swimmeret alters motor programs for abdominal posture in the lobster Homarus americanus. J Comp Physiol [A] 158, 225-33.
The influence of mechanosensory stimulation of a second segment swimmeret upon the abdominal postural program was examined in an isolated abdominal nerve cord-swimmeret preparation. The swimmeret was stimulated in several different ways to assess the extent of influence exerted on abdominal positioning. Localized tactile stimulation of the swimmeret surface with a mechanical probe usually generated flexion inhibition where the flexor inhibitor (f5) was activated while the small and medium flexor excitors were inhibited. Flexion inhibition was much stronger in females than males. In 50% of the animals a weak flexion excitation was seen. After 3-6 hours the response of one-third of these preparations changed to flexion inhibition. Strong manual stimulation of the swimmeret surface inhibited all of the flexor excitors (f1, f2, f3, f4, and f6) while exciting the inhibitor f5 and increasing extensor activity. Similar extension responses were observed in both sexes. Repeated tactile stimulation of the swimmeret surface elicited a response similar to that evoked during manual stimulation. The strongest extension response was produced at 2 Hz which falls within the normal range of swimmeret beating in intact lobsters. Similar extension responses were also obtained during spontaneous swimmeret beating and rhythmic manual movement of the swimmeret.(ABSTRACT TRUNCATED AT 250 WORDS).
Kotov, A. A., and Boikova, O. S. (1998). Comparative analysis of the late embryogenesis of Sida crystallina (O.F. Muller, 1776) and Diaphanosoma brachyurum (Lievin, 1848) (Crustacea : Branchiopoda : Ctenopoda). Hydrobiologia 380, 103-125.
The embryonic development of two ctenopods Sida crystallina and Diaphanosoma branchyurum has been investigated by observing living embryos removed from the female brood pouches. The sequence of morphological changes was analysed, as was the time at which the activity of certain organs began. The timing of these events at 21-22 degrees C is documented for both species. During embryogenesis four membranes are cast off. The growth in length of embryos began only after the shedding of the external egg envelope. Growth rates throughout embryogenesis are documented. A new outline of ctenopod embryogenesis is proposed. It includes four stages (= instars) demarcated by the shedding of membranes (= moults), as is commonly accepted for juvenile and mature animals in ctenopods and other crustacean groups. These instars are well distinguished morphologically. Their characteristics are presented. Differences in the duration of embryogenesis in Sida and Diaphanosoma are explained by greater extension of the first, and especially the fourth, instars of Sida, while the duration of the second and third instars are approximately the same in both. A list of instar features is given which may be used to determine the instar (and approximate age) of embryos in the brood pouch of ctenopod females from natural populations.
Kragh, M., Molbak, L., and Andersen, S. O. (1997). Cuticular proteins from the lobster, Homarus americanus. Comparative Biochemistry and Physiology B-Biochemistry & Molecular Biology 118, 147-154.
The urea-extractable proteins from calcified regions of intermoult. cuticle of the lobster, Homarus americanus, have been separated by two-dimensional electrophoresis, showing that the extracts contain a large number of proteins. The major proteins have isoelectric points between 4 and 9, and their apparent molecular weights are between 5 and 30 kDa. Two of the proteins have been purified by a combination of ion-exchange chromatography, gel-filtration and RP-HPLC, and their complete amino acid sequences were determined by a combination of mass spectrometry and automated Edman degradation. Although they were purified from a single animal, both proteins were obtained as two isoforms. The isoforms of the smaller protein (HaCP4.6) differed only in a single position (phenylalanine/isoleucine), and the isoforms of the larger protein (HaCP11.6) differed in two positions (valine/isoleucine and glutamine/lysine). HaCP11.6 is N-terminally blocked by a pyroglutamate residue. Variants of an 18-residue motif are a characteristic feature of both sequences: it occurs twice in HaCP4.6 and four times in HaCP11.6. Comparison of the sequences to sequences published for cuticular proteins from other arthropods shows that the repeated motif is also present in proteins from the exoskeleton of the Bermuda land crab, Gecarcinus lateralis, but not in the single shrimp protein (Pandalus borealis) sequenced so far. The amino acid compositions of the lobster proteins are similar to that of flexible cuticles in locusts, but no convincing sequence similarities were found between the lobster proteins and cuticular proteins from locusts or other insects. (C) 1997 Elsevier Science Inc.
Kreider, J. L., and Watts, S. A. (1998). Behavioral (feeding) responses of the crayfish, Procambarus clarkii, to natural dietary items and common components of formulated crustacean feeds. Journal of Chemical Ecology 24, 91-111.
We have examined the behavioral (feeding) response of Procambarus clarkii to natural dietary items (zooplankton, live fishes, dead fishes, and fish eggs) and common components of formulated feeds used in the aquaculture industry (soybean meal, fish meal,;om meal, alfalfa meal, and vitamin C). The feeding response by P. clarkii was determined using an ordinally ranked, whole-animal bioassay that included the following behaviors: (1) movement of the maxillipeds for longer han three seconds, (2) increased movement of the walking legs with dactyl "probing," (3) movement of walking legs to the mouth, and (4) orientation of the entire body towards the odor source. Feeding behavior was determined in response to intact items: bathwater containing aqueous leachates from intact items, water and methanol fractions of bathwater eluted through a C-18 resin Rash chromatography column, and size fractions of bathwater containing either molecules less than or equal to 10,000 Da or molecules > 10,000 Da. All fractions tested were significantly stimulatory. Zooplankton was the most stimulatory of the natural dietary items tested. However, the C-18 water fraction of the soybean meal bathwater before size fractionation (containing molecules both < 10,000 and > 10,000 Dal was the most stimulatory of the common feed components and more stimulatory than the zooplankton. Proximate analysis indicated that the compounds present in this fraction were ca. 51% soluble carbohydrate, 4% soluble protein, and 45% unknown (assumed to be insoluble carbohydrates, insoluble proteins, and ash). We hypothesize that the primary compounds in soybean meal responsible for eliciting a feeding response in P. clarkii are soluble carbo hydrates and/or glycoproteins.
Kucharski, L. C., Ribeiro, M. F., Schein, V., DaSilva, R. S. M., and Marques, M. (1997). Insulin binding sites in gills of the estuarine crab Chasmagnathus granulata. Journal of Experimental Zoology 279, 118-125.
Bovine I-125-insulin was injected into the estuarine crab Chasmagnathus granulata in order to study its distribution and specific uptake by tissues. The highest radioactivity uptake occurred in both anterior and posterior gills, which reached maximum values at 30-60 min following labeled insulin administration. Heart and hepatopancreas concentrated a very low amount of radioactivity (only 9 and 3%, respectively, of that shown by gills). A significant reduction of the uptake was observed in the gills when an excess of unlabeled insulin was injected together with the labeled hormone. In vitro studies also showed specific uptake of I-125-insulin by the gills incubated at 25 degrees C, which reached a plateau after 120- min incubation, suggesting a saturable process. The inhibition of I-125-insulin uptake was dose dependent on unlabeled insulin. Glucagon did not compete with radioactivity uptake by gills in vivo and in vitro. Further characterization of insulin-binding sites was performed in gill membrane. The amount of unlabeled insulin that prevented 50% of the I-125- insulin uptake was 7.78 mu g/ml, and the Scatchard plot analysis established the presence of binding site with Kd of 3.11 mu M and Bmax of 0.14 mu M (r = 0.99). Ovine prolactin was not able to prevent I-125-insulin binding to gill membrane. These findings seem to indicate the presence of specific binding sites for insulin or insulin-like substance in crab gills, which deserves further studies. (C) 1997 Wiley-Liss, Inc.
Kyomo, J. (1999). Distribution and abundance of Crustaceans of commercial importance in Tanzania mainland coastal waters. Bulletin of Marine Science 65, 321-335.
Crustacean species of commercial importance were identified and their abundance and distribution along the Tanzanian coastline (820 km) were determined. A total of eight lobster species, eight prawn species, and two crab species were identified. Among the spiny lobster species (Palinuridae), Panulirus ornatus was the most widely distributed and the most abundant species with 42% of the total individuals sampled and P. homarus and P. penicillatus were the least abundant. The non- spiny lobster Thanus orientalis and two Other scyllarid (Scyllaridae) species, Palribacus antarcticus and Scyllarides squamosus were also found in Tanzania, though in very small numbers and of least or no commercial value in the area. Among the prawn species, Metapenaeus monoceros was the most widely distributed, and the most abundant species comprising of about 45% of the total individuals sampled. Lowest distribution and abundance were recorded for Penaeus japonicus (1.2%). The commercially important crabs were Portunus pelagicus and Scylla serrata (Portunidae) and their abundance and distribution were the same. These crustaceans are a major source of income for some local fishermen, but does not contribute as one of the major sources of protein for the population of Tanzania.
Lacombe, C., Greve, P., and Martin, G. (1999). Overview on the sub-grouping of the crustacean hyperglycemic hormone family. Neuropeptides 33, 71-80.
The Crustacean hyperglycemic hormones (CHHs) are an ever extending family of crustacean hormones mainly involved in carbohydrate metabolism, molt and reproduction. In this paper, we drew together 32 available CHH sequences, and applied the techniques of multiple sequence alignment, motif searching and amino acid conservation analysis to the characterization of the molecules independently of their biological function. The analysis clearly showed that the proteins clustered into two groups (CHH and VIH). Amino acid conservation analysis also subdivided the VIH group into sequences involved in reproduction (RIH) or in molt (MIH). Motif searching identified five motifs in each group of mature hormones. Motifs A2 and A3 were conserved in all sequences while motifs Al and A1' were specific of the CHH and VIH groups respectively. This approach demonstrated the S. gregaria ion transport peptides as true members of the CHH group. The two main groups, CHH and VIH, are also discussed in terms of functional homogeneity.
Lang, F., Costello, W. J., and Govind, C. K. (1977). Development of the dimorphic claw closer muscles of the lobster Homarus americanus: L Regional distribution of muscle fiber types in adults. Biol Bull 152, 75-83.
1. The closer muscles of the dimorphic claws (chelipeds) were studied for the presence and location of fast and slow muscle fibers. 2. Cutter claws were composed of about 60-70% short sarcomere (less than 4 mum) fast fibers; the remainder was longer sarcomere (greater than 6 mum) slow and intermediate (4-6 mum) fibers. 3. Crusher claws were composed of a uniform population of long sarcomere (6-13 mum) slow and intermediate (4-6 mum) fibers. 4. There was a regional distribution of fibers in the cutter claw. Ventral fibers were predominantly slow. Dorsal fibers and central medial fibers were fast. Proximal and distal fibers in the medial section were usually mixed. 5. The regional distribution of cutter fibers correlates with previous physiological studies on the distribution of the fast and slow motor axons to these muscle fibers.
Lang, F., Cleveland, M. B., and Atwood, H. L. (1979). Mg++-sensitivity of neuromuscular transmission in two crustaceans: correlation with blood Mg++ levels. J Neurobiol 10, 609-14.
Neuromuscular transmission was measured in muscles of spider crabs (Hyas areneus) and lobsters (Homarus americanus). Solutions containing 40 and 10 mM/1 Mg++, which were approximately the same as those measured in the blood of Hyas and Homarus, respectively, were used to soak the preparations prior to testing. In Homarus, neuromuscular transmission was severely depressed by 40 mM Mg++. In spider crabs, neuromuscular transmission was not severely depressed. Although the amount of transmitter released by nerve impulses was reduced, total membrane depolarization during trains of impulses was not reduced because a compensating increase in muscle fiber membrane resistance occurred in Hyas preparations exposed to M Mg++. Hyas, but not Homarus, is physiologically adapted to function at relatively high blood Mg++ concentrations.
Lardies, M. A., Rojas, J. R., and Wehrtmann, I. S. (1998). Breeding biology of the snapping shrimp Betaeus emarginatus inhabiting a rock pool environment in central-southern Chile (Decapoda : Caridea : Alpheidae). Ophelia 49, 221-231.
The present study describes the seasonality of egg production, the gonad cycle, the development of secondary sexual characteristics, and the size at first maturity of the caridean shrimp Betaeus emarginatus, a typical inhabitant of intertidal rock pools. A total of 1118 individuals (including 298 ovigerous females) was collected monthly from May 1993 to December 1994 in central-southern Chile. The sex ratio was 1.1 : 1.0, and males reached larger sizes than females. Degeneration of the appendix masculina with increasing size was not evident, indicating that B. emarginatus is a dioecious species. The onset of sexual maturity of females was reached between 8.0 and 9.0 mm carapace length. Ovigerous females were present between May and December and were absent between January and April. The breeding season started during late autumn (May), and females with embryos close to hatching occurred between mid winter (July) and the end of the spring (December). On the bases of the embryonic development, duration of the incubation period, and gonadosomatic index, it is evident that B. emarginatus has a markedly seasonal breeding period with probably two successive spawnings per female per season. The absence of ovigerous females during the summer months (January and April) may limit breeding to periods with conditions most suitable for hatching larvae, thus increasing the survival of progeny.
Laughlin, R. B., Jr., and French, W. J. (1980). Comparative study of the acute toxicity of a homologous series of trialkyltins to larval shore crabs, Hemigrapsus nudus, and lobster, Homarus americanus. Bull Environ Contam Toxicol 25, 802-9.
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Laverack, M. S., Macmillan, D. L., and Neil, D. M. (1976). A comparison of beating parameters in larval and post-larval locomotor systems of the lobster Homarus gammarus (L.). Philos Trans R Soc Lond B Biol Sci 274, 87-99.
A study has been made of the interrelations between rhythmical exopodite beating in different larval stages and swimmeret beating in poast-larval stages of the lobster Homarus gammarus. Data on exopodite beat cycle durations have been used for statistical comparisons of exopodite performance within one larva, and also between different stages of larval development. Inter-exopodite comparisons reveal clear bilateral differences (table 1), although there is no consistently favoured relationship (tables 2 and 3). There are significant differences in cycle duration between the first three developmental stages, with a slight increase at the first moult, and a marked decrease at the second (table 4). However, within each stage the repeat frequency exhibits little change (table 5). Therefore it appears that changes in swimming behaviour occur discontinuously in development, and are associated with the larval moults. It is suggested that changes in beat frequency, and especially the faster beating in stage III, may represent responses to changed loading conditions (table 7). Measurements of swimmeret beating in post-larval lobsters have been analysed in terms of cycle durations, and inter- and intra-segmental phase relations. Swimmeret beating patterns are very regular (figure 1), but not restricted to a narrow range of frequencies (table 6a). Intersegmental phase lag remains constant around 0.2 (figure 3) independent of beat frequency (figure 4). Similarly the powerstroke/returnstroke ratio of approximately 0.5 (figure 5) shows no significant correlation with cycle duration (figure 6). Differences emerge in the performance of larval exopodites and post-larval swimmerets (table 6b), although the possibility cannot be excluded that the larval exopodite oscillator in some way influences the developing action of the post-larval swimmeret system.
Laverdure, A. M., Breuzet, M., Soyez, D., and Becker, J. (1992). Detection of the mRNA encoding vitellogenesis inhibiting hormone in neurosecretory cells of the X-organ in Homarus americanus by in situ hybridization. Gen Comp Endocrinol 87, 443-50.
Vitellogenesis inhibiting hormone (VIH)-mRNA in secretory cells of the eyestalk of Homarus americanus was detected by nonradioactive in situ hybridization (ISH) using two digoxigenin-tailed oligonucleotide probes deduced from the peptide sequence. Two distinct clusters of positive cells were observed in the medulla terminalis ganglionic X-organ (MGTX). Only one of them gave a strong immunoreaction after incubation with a specific polyclonal anti-VIH serum and corresponded to the conventionally described VIH producing cells. The significance of the cells reacting positively in ISH but not in immunocytochemistry (ICC) is discussed. Northern blot analysis using 32P-labeling confirms the specificity of the probes and indicates an approximate size of 2.5 kb for VIH mRNA.
Laverdure, A. M., Carette-Desmoucelles, C., Breuzet, M., and Descamps, M. (1994). Neuropeptides and related nucleic acid sequences detected in peneid shrimps by immunohistochemistry and molecular hybridizations. Neuroscience 60, 569-79.
The neurosecretory cells in the eyestalks of Penaeus indicus and P. vannamei were studied by immunocytochemistry using polyclonal antisera raised against purified Homarus americanus neuropeptides. Cross- reactions between two H. americanus anti-crustacean hyperglycemic hormone antisera and Penaeus neurosecretory material were observed. The specific anti-vitellogenesis inhibiting hormone antiserum only showed an immunological reaction in the nervous tract and the sinus gland of Penaeus, suggesting a progressive exposure of a characteristic epitope which was amenable to immunological detection. Molecular hybridizations were performed in P. indicus and P. vannamei with a digoxigenin tailed 23mer oligonucleotide probe deduced from two partial sequences of uncharacterized, purified P. duorarum neuropeptides. Two distinct clusters of positive cells were observed by in situ hybridization experiments in the medulla terminalis ganglionic X-organ. Classical control tests gave negative results. Northern and Southern blot analyses were performed with the same tailed probed and allowed the determination of molecular weights for the mRNA and for a DNA restriction fragment (Pst 1), 1.7 kb and 200 bp, respectively. These observations show the existence of a strong homology between the P. duorarum sequence (selected for synthesizing the probe), and some P. indicus and P. vannamei neuropeptide sequence(s). Heterologous antisera were tested in other Arthropods to complete our analyses. In the centipede Lithobius forficatus and the scorpion Euscorpius carpathicus, the anti-crustacean hyperglycemic hormone antiserum induced a strong cross-reaction. A monoclonal anti-bombyxin-1 antiserum showed an immunoreaction in the neurosecretory system of the insects Tenebrio molitor and Labidura riparia. In contrast, the anti-bombyxin-1 antiserum did not react either in Penaeus or in Lithobius, and the Homarus hyperglycemic hormone antiserum did not react in the insects that were tested. A comprehensive view of these observations is discussed in relation to a divergence in Arthropod evolution.
Lawrence, J. F., Maher, M., and Watson-Wright, W. (1994). Effect of cooking on the concentration of toxins associated with paralytic shellfish poison in lobster hepatopancreas. Toxicon 32, 57-64.
The hepatopancreases from lobsters (Homarus americanus) obtained from two locations in eastern Canada (Gaspe and Bay of Fundy) were analysed for paralytic shellfish poisons (PSP) before and after the shellfish were cooked by boiling or steaming. Forty-five lobsters from each location were divided into three groups of 15. Two of the groups were boiled or steamed while the third was uncooked for comparison purposes. The hepatopancreases of all lobsters were individually analysed for total PSP toxicity using the standard mouse bioassay procedure. Individual toxins were determined in each sample using a high- performance liquid chromatographic procedure employing pre- chromatographic oxidation of the toxins to form fluorescent derivatives. The results demonstrated that boiling or steaming reduced total toxicity (measured as saxitoxin equivalents per hepatopancreas) by approximately 65% compared to values obtained from raw lobsters. Of the individual toxins studied, saxitoxin decreased by about 60% with both the cooking treatments while gonyautoxins 2 and 3 (combined) decreased by almost 100% in the Gaspe samples and by about 90% in the Fundy samples with the same cooking treatments. Trace amounts of saxitoxin or gonyautoxins 2 and 3 were detected in some samples of tail or claw meat before or after cooking. In vitro boiling of raw hepatopancreas for up to 30 min led to no change in total or individual PSP concentration, indicating that the toxins in cooked lobster are not removed through chemical decomposition but are leached out during the loss of water.
Laycock, M. V., Hirama, T., Hasnain, S., Watson, D., and Storer, A. C. (1989). Purification and characterization of a digestive cysteine proteinase from the American lobster (Homarus americanus). Biochem J 263, 439-44.
A new cysteine proteinase was isolated from the digestive juice of the American lobster (Homarus americanus). The enzyme was purified by a combination of affinity and ion-exchange chromatography and gel filtration. The cysteine proteinase accounted for 80% of the proteolytic activity in the lumen of the hepatopancreas. The most potent heavy-metal inhibitors were Hg, Cu, and Ag ions. Inhibition by organic proteinase inhibitors, including E-64 [L-trans-epoxysuccinyl- leucylamido-(4-guanidino)butane] and activation of the enzyme by 2- mercaptoethanol and dithiothreitol are characteristic of cysteine proteinases. Several similarities to papain are noted and include the N- terminal sequence, of which 22 of the first 28 amino acids are identical. Some notable differences are the higher Mr of 28,000 compared with 23,350 for papain, and the low isoelectric point (pI 4.5) of the lobster enzyme. The effects of pH and temperature on catalytic activity of the lobster proteinase were studied with benzyloxycarbonylalanine p-nitrophenyl ester as the substrate. The kcat./Km value was effectively temperature-independent between 10 and 60 degrees C. The pH-activity profile for the lobster enzyme revealed four apparent protonation states, of which only two are active.
Laycock, M. V., MacKay, R. M., Di Fruscio, M., and Gallant, J. W. (1992). Molecular cloning of three cDNAs that encode cysteine proteinases in the digestive gland of the American lobster (Homarus americanus). FEBS Lett 301, 125.
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Le Boulay, C., Van Wormhoudt, A., and Sellos, D. (1996). Cloning and expression of cathepsin L-like proteinases in the hepatopancreas of the shrimp Penaeus vannamei during the intermolt cycle. J Comp Physiol [B] 166, 310-8.
Cysteine protease activities have been characterized with benzyloxycarbonyl-lysine p-nitrophenyl ester as a synthetic substrate and E64 as a specific inhibitor in the hepatopancreas of the shrimp Penaeus vannamei. An optimum pH of 5.1 has been measured. To characterize these cysteine proteases, a hepatopancreas cDNA library was screened by hybridization to a Norway lobster cysteine protease cDNA fragment. Two cDNAs encoding P. vannamei cysteine protease precursors have been cloned and sequenced. The encoded polypeptides have 326 and 322 amino acid residues, respectively, each consisting of partial signal sequences (15 and 10 residues), a pro-region (93 and 94 residues), and a mature enzyme polypeptide (218 residues). Cys25, His159 and Asn175 form the catalytic triad in the putative active site of the mature enzymes. Compared with invertebrate cysteine proteases (Homarus and Fasciola), each of the two shrimp enzymes shows 70 and 52% amino acid sequence identity, respectively; 63% identity is shown with rat cathepsin L. Northern hybridization analysis showed the same size for the different cysteine protease transcripts in hepatopancreas tissue (approximately 1.1 kb). During intermolt cycles, variations in cysteine protease activity were correlated with the variations in the levels of specific mRNA.
Leung, P. S. C., Chen, Y. C., Mykles, D. L., Chow, W. K., Li, C. P., and Chu, K. H. (1998). Molecular identification of the lobster muscle protein tropomyosin as a seafood allergen. Molecular Marine Biology and Biotechnology 7, 12-20.
Crustaceans are a major cause of seafood allergy, Recent studies have identified tropomyosin as the major allergen in shrimp. However, such data are lacking in other crustaceans, In the present study lobster allergens were identified and characterized by molecular cloning, sequencing, and expression. An IgE-reactive complementary DNA clone of 2 kilobase pairs (kb) was identified by screening an expression library of the spiny lobster Panulirus stimpsoni using sera from subjects with crustacean allergy. Expression and sequencing of this clone showed that it has an opening reading frame of 274 amino acids, coding far a 34-kDa protein designated as Pan s I. In addition, we expressed the fast muscle tropomyosin from the American lobster Homarus americanus and found that this protein, coined Horn a I, was also recognized by IgE from patients with crustacean allergies. The deduced amino acid sequences of Pan s I and Hom a I, which are the first identified lobster allergens, show significant homology to shrimp tropomyosin. Sera from subjects with crustacean allergies, when pre-absorbed with recombinant proteins Pan s I or Hom a I, lost their IgE reactivity to muscle extract of P. stimpsoni and H. americanus. Preincubation of crustacean allergy sera with the recombinant shrimp tropomyosin Met e I also removed their IgE reactivity to lobster muscle extracts. The results suggest that patients with allergic reactions to crustaceans have common and possibly cross-reactive IgE-reactive epitopes in lobster and shrimp.
Levine, R. J., Elfvin, M., Dewey, M. M., and Walcott, B. (1976). Paramyosin in invertebrate muscles. II. Content in relation to structure and function. J Cell Biol 71, 273-9.
By quantitative sodium dodecyl sulfate-polyacrylamide gel electrophoresis, paramyosin:myosin heavy chain molecular ratios were calculated for three molluscan muscles:Aequipecten striated adductor, Mercenaria opaque adductor, and Mytilus anterior byssus retractor; and four arthropodan muscles:Limulus telson, Homarus slow claw. Balanus scutal depressor, and Lethocerus air tube retractor. These ratios correlate positively with both thick filament dimensions and maximum active tension development in these tissues. The role of paramyosin in these muscles is discussed with respect to the following characteristics: force development, "catch," and extreme reversible changes in length.
Li, C. L. J., and James, M. O. (1997). Pharmacokinetics of 2-naphthol following intrapericardial administration, and formation of 2-naphthyl-beta-D-glucoside and 2-naphthyl sulphate in the American lobster, Homarus americanus. Xenobiotica 27, 609-626.
1. Following a 0.25-mg/kg intrapericardial dose of the phenolic compound, 2-naphthol, to the American lobster, Homarus americanus, a two-compartment model best described the disposition of parent [C-14]-2-naphthol in the haemolymph, Male and female lobsters had similar a-phase half lives of 26 +/- 19 min (mean +/- SD, n = 4) and 29 +/- 15 min respectively. The P- phase half lives were significantly longer in males, 63.9 +/- 30.9 h, than in females, 30.6 +/- 6.8 h (p < 0.05). The total body clearance for females was 26.4 +/- 6.5 ml x h(-1) x kg(-1) and was higher than that of males, 11.1 +/- 5.9 ml x h(-1) x kg(-1) (p < 0.05). 2. 2-Naphthol was converted to 2-naphthyl- beta-D-glucoside (major metabolite) and 2-naphthyl sulphate (minor metabolite) such that at 24 h 39-60.6% of the radioactivity in haemolymph was 2-naphthyl-beta-D-glucoside, 38.6-58.9% 2-naphthol and 0.5-4% 2-naphthyl sulphate. 3. The 2- naphthol-derived radioactivity was > 99% bound to haemolymph proteins at 1 min and > 90% bound al 1 day after the dose, indicating that both 2-naphthol and 2-naphthyl l-P-D-glucoside were highly protein bound. 4. 2-Naphthyl-beta-D-glucoside was slowly eliminated from haemolymph in both males and females, with elimination half lives of 34-78 h. 2-Naphthyl-beta-D- glucoside was the major metabolite in urine samples collected at 5 days after the dose. Hepatopancreas and antennal gland contained glucosidase activities, and the long half life of 2- naphthyl-beta-D-glucoside could be explained by conjugation- deconjugation cycling. 5. 2-Naphthyl sulphate was eliminated from haemolymph with a half-life < 10 h and was excreted in urine.
Li, C. L. J., and James, M. O. (1998). The oral bioavailability, pharmacokinetics and biotransformation of 9-hydroxybenzo[a]pyrene in the American lobster, Homarus americanus. Marine Environmental Research 46, 505-508.
The pharmacokinetics of [H-3]-9-hydroxy-benzo[a]pyrene (9-OH- BaP) were examined after single intrapericardial (IV) or oral doses to intermolt American lobsters, Homarus americanus, A three-compartment model best described the disposition of parent 9-OH-BaP in the hemolymph after IV administration. The major metabolite found in hemolymph 8 h after administration, BaP 9-sulfate, reached ifs peak concentration at one day after the dose. BaP 9-sulfate was eliminated from hemolymph more rapidly than 9-OH-BaP or BaP9-beta-D-glucoside, which were present in all hemolymph samples at all limes. The oral bioavailability if for 9-OH-BaP, estimated from the ar ea under concentration-time curve (AUC), ranged from 3.4 to 14.3%. bn a:ll treated lobsters, <10% dose Mas left in tissues at 10 days. PAPS-sulfotransferase (ST) and UDP-glucosyltransferase (UDP-GT) activities,were defected in the intestinal mucosa as well as in the antennal gland (ST) and the hepatopancreas (UDP- GT). These studies showed that 9-OH-BaP and its sulfate and glucoside conjugates were excreted from lobster tissues more rapidly than BaP, but were retained by the lobster for longer than the smaller, less lipophilic phenolic compounds, phenol and beta-naphthol and their metabolites. (C) 1998 Elsevier Science Ltd. All rights reserved.
Lightner, D. V., and Fontaine, C. T. (1975). A mycosis of the American lobster, Homarus americanus, caused by Fusarium sp. J Invertebr Pathol 25, 239-45.
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Lignot, J. H., Trilles, J. P., and Charmantier, G. (1997). Effect of an organophosphorus insecticide, fenitrothion, on survival and osmoregulation of various developmental stages of the shrimp Penaeus japonicus (Crustacea: Decapoda). Marine Biology 128, 307-316.
The toxicity of fenitrothion was determined in larvae (nauplii, Zoeae 1 to 3, Mysis 1 to 3); postlarvae (PL stages) and juvenile shrimp (Penaeus japonicus Bate), in two media, seawater (SW) and diluted seawater (DSW) (1100 and 550 mosMkg(- 1),similar or equal to 37 and 19 parts per thousand S). The effects of fenitrothion on the osmoregulatory capacities (OC) of juveniles were recorded. A gill and epipodite histopathological study was also conducted. For larvae in seawater, 24 and 48 h LC(50)s ranged from 32.9 mu g 1(-1) (Zoeae 2) to 10.7 mu g 1(-1) (Mysis 3), and from 3.9 mu g 1(-1) (Zoeae 3) to 2.0 mu g 1(-1) (Mysis 3), respectively; 48 and 96 h LC(50)s in postlarvae (PL) at the same salinity ranged from 1.8 mu g 1(-1) (PL1) to 0.6 mu g 1(-1) (PL5), and from 0.3 mu g 1(-1) (PL7) to 0.4 mu g 1(-1) (PL15). In juveniles, 96 h LC(50)s were 0.8 mu g 1(-1) in seawater and 1.5 mu g 1(-1) in diluted seawater. From hatching to juvenile stages, the overall trend was a rapid decrease (from nauplii to PL5-PL7) followed by a slight increase (from PL7 to PL15 and juveniles) in the shrimp's ability to tolerate the insecticide. In juveniles kept in seawater and in diluted seawater, fenitrothion decreased the osmoregulatory capacity (OC = difference between the hemolymph osmotic pressure and the osmotic pressure of the medium) at both lethal and sublethal concentrations. This effect was time- and dose-dependent. In SW, the decrease in hypo-OC was similar to 25% at sublethal concentrations and similar to 35% at the 96 h LC50. In DSW, the decrease in hyper-OC was similar to 10 to 15% at sublethal concentrations. In SW, shrimp were able to recover their OC in less than 48 h when transferred to water free of pesticide. In DSW, recovery at 48 h was only possible after exposure to the lowest tested sublethal concentration. Haemocytic congestions (thrombosis) of the gills, lamellae necrosis and other alterations of gills and epipodites (breakage of the cuticle, reduction of the hemolymph lacunae) were noted in juveniles exposed to lethal and sublethal concentrations of fenitrothion.
Lignot, J. H., Pannier, F., Trilles, J. P., and Charmantier, G. (1998). Effects of tributyltin oxide on survival and osmoregulation of the shrimp Penaeus japonicus (crustacea, decapoda). Aquatic Toxicology 41, 277-299.
The acute toxicity of tributyltin oxide (TBTO) was determined in larvae (nauplii, zoeae 1-3. mysis 1-3), post-larvae (PL stages) and juvenile shrimp (Penaeus japonicus Bate), in two media, seawater (SW) and diluted seawater (DSW; 1100 and 550 mosm kg(-1) approximate to 37 and 19%). survival, osmoregulatory capacity and Na+-K+ ATPase activity were measured. A gill and epipodite histopathological study was also conducted. The 24 and 48 h LC(50)s values for TBTO in SW ranged from 2.03 mu g 1(-1) (1.7-2.4) and 0.88 mu g 1(-1) (0.8-1.0) for nauplii to 773 mu g 1(-1) (344-1823) and 708 mu g 1(-1) (361-1608) for juveniles. The 96 h LC(50)s values in SW ranged from 19.4 mu g 1(-1) (12.6-27.3) for PL5 to 370 mu g 1(-1) (202-662) for juveniles. The 96 h LC50 value was not affected by salinity in juveniles. Tolerance to TBTO tended therefore to increase with the development from larval to juvenile instars. In juveniles kept in SW and in DSW, acute TBTO-exposures decreased the osmoregulatory capacity (OC = difference between the hemolymph osmolality and the osmolality of the medium) of animals exposed to lethal and sublethal concentrations. Effects of TBTO exposure on hypo-and hyper-OC were time-and dose- dependent and the ability to osmoregulate was recovered after exposure of the shrimp to water free of TBTO for 48-120 h. These experiments confirmed OC as a valuable tool for monitoring the physiological state of peneid shrimp. Gill and epipodite Na+-K+ ATPase activities were not altered in SW and DSW after acute TBTO-exposures, either at sublethal or at lethal concentrations. Haemocytic congestion (thrombosis), multiple necrosis and nephrocyte hyperplasia were observed in gill lamellae of exposed shrimp. Multiple necrosis and lacunae in the epithelial monolayers were also observed in epipodites. At lethal concentrations, the interconnecting lacunae were reduced and!or replaced by proliferating tissues. Epithelial cells were peeling and oedema was observed. For both tissues, histopathological effects increased with the dose and they are probably the cause of impaired osmoregulation. (C) 1998 Elsevier Science B.V. All rights reserved.
Lignot, J. H., Charmautier-Daures, M., and Charmantier, G. (1999). Immunolocalization of Na+,K+-ATPase in the organs of the branchial cavity of the European lobster Homarus gammarus (Crustacea, Decapoda). Cell and Tissue Research 296, 417-426.
The localization of Na+,K+-ATPase in epithelia of the organs of the branchial cavity of Homarus gammarus exposed to seawater and dilute seawater was examined by immunofluorescence microscopy and immunogold electron microscopy with a monoclonal antibody IgG alpha(5) raised against the avian alpha-subunit of the Na+,K+-ATPase. In juveniles held in seawater, fluorescent staining was observed only in the epithelial cells of epipodites. In juveniles held in dilute seawater, heavier immunoreactivity was observed in the epithelial cells of epipodites, and positive immunostaining was also observed along the inner-side epithelial layer of the branchiostegites. No fluorescent staining was observed in the gill epithelia. At the ultrastructural level, the Na+,K+-ATPase was localized in the basolateral infolding systems of the epipodite and inner-side branchiostegite epithelia of juveniles held in dilute seawater, mostly along the basal lamina. The expression of Na+,K+-ATPase therefore differs within tissues of the branchial cavity and according to the external salinity. These and previous ultrastructural observations suggest that the epipodites, and to a lesser extent the inner-side epithelium of the branchiostegites, are involved in the slight hyper-regulation displayed by lobsters at low salinity. Enhanced Na+,K+-ATPase activity and de novo synthesis of Na+,K+-ATPase within the epipodite and branchiostegite epithelia may be key points enabling lobsters to adapt to low salinity environments.
Lignot, J. H., Cochard, J. C., Soyez, C., Lemaire, P., and Charmantier, G. (1999). Osmoregulatory capacity according to nutritional status, molt stage and body weight in Penaeus stylirostris. Aquaculture 170, 79-92.
Hypo-osmoregulatory capacity (or hypo-OC, i.e., the difference between the osmolality of the haemolymph and that of sea water), haemolymph glycemia and haemolymph sodium and chloride concentrations of Penaeus stylirostris were studied in experimental tanks according to the size, the molt stage and the nutritional status of the shrimp. Osmolality and haemolymph glycemia of fed and starved P. stylirostris were also studied in earthen ponds in fluctuating sea water according to time. In experimental tanks, the absolute hypo-OC of shrimp decreased linearly with increasing wet weight for each molt stage considered. For specimens weighing 16.6 +/- 1.7 g, the absolute hypo-OC was maximum in stage C (217 +/- 17 mosm kg(-1)) and significantly lower in stages B (165 +/- 16 mosm kg(-1)), D-0 (181 +/- 18 mosm kg(-1)), D-1 (146 +/- 20 mosm kg(-1)) and D-2 (135 +/- 13 mosm kg(-1)). The hypo-OC and haemolymph glucose concentration varied significantly after the food supply. No variations in haemolymph sodium and chloride concentrations were observed. In earthen ponds, haemolymph osmolality and haemolymph glucose concentration of molt stage C shrimp increased shortly after the food supply. When shrimp were kept starved for 24 and 48 h, haemolymph osmolality remained constant and haemolymph glucose concentration varied only slightly according to time. In light of these results, the use of shrimp hypo-OC (and/or haemolymph osmolality) and haemolymph glycemia in aquaculture as potential physiological indicators of disturbance in the aquatic environment is discussed. (C) 1999 Elsevier Science B.V. All rights reserved.
Lignot, J. H., Charmantier-Daures, M., and Charmantier, G. (1999). Immunolocalization of Na+,K(+)-ATPase in the organs of the branchial cavity of the European lobster Homarus gammarus (Crustacea, Decapoda). Cell Tissue Res 296, 417-26.
The localization of Na+,K(+)-ATPase in epithelia of the organs of the branchial cavity of Homarus gammarus exposed to seawater and dilute seawater was examined by immunofluorescence microscopy and immunogold electron microscopy with a monoclonal antibody IgG alpha 5 raised against the avian alpha-subunit of the Na-,K(+)-ATPase. In juveniles held in seawater, fluorescent staining was observed only in the epithelial cells of epipodites. In juveniles held in dilute seawater, heavier immunoreactivity was observed in the epithelial cells of epipodites, and positive immunostaining was also observed along the inner-side epithelial layer of the branchiostegites. No fluorescent staining was observed in the gill epithelia. At the ultrastructural level, the Na+,K(+)-ATPase was localized in the basolateral infolding systems of the epipodite and inner-side branchiostegite epithelia of juveniles held in dilute seawater, mostly along the basal lamina. The expression of Na+,K(+)-ATPase therefore differs within tissues of the branchial cavity and according to the external salinity. These and previous ultrastructural observations suggest that the epipodites, and to a lesser extent the inner-side epithelium of the branchiostegites, are involved in the slight hyper-regulation displayed by lobsters at low salinity. Enhanced Na+,K(+)-ATPase activity and de novo synthesis of Na+,K(+)-ATPase within the epipodite and branchiostegite epithelia may be key points enabling lobsters to adapt to low salinity environments.
Lim, B. K., Sakurai, N., Sugihara, T., and Kittaka, J. (1997). Survival and growth of the American lobster Homarus americanus fed formulated feeds. Bulletin of Marine Science 61, 159-163.
There may be an opportunity to culture American lobsters (Homarus americanus) in Japan using warmed seawater from thermal effluent of power generating stations. Growth parameters for culture lobsters were compared between groups fed two artificial diets (feed A and feed B) or a standard rotational diet. The rotational diet consisted of frozen shrimp, lugworm, and pelleted kuruma prawn feed given on alternate days. The principal protein sources for formulated feed A were squid meal, fish meal, salmon roe meal and prawn meal (in the proportions 43:29:14:14), and for formulated feed B the sources were squid meal, fish meal and shrimp meal (in the proportions 35:29:36). Each diet was given to 14 individually reared juvenile lobsters (13th-14th stage, wet body weight ca. 10 g), maintained at 18 +/- 2 degrees C for 150 d. Survival in all three treatments was high (ca. 80%) and not significantly different. There were no significant differences between lobsters fed feed A or B in molting frequency (mean +/- SD: 2.5 +/- 0.5 vs. 2.2 +/- 0.5); weight gain ration per molt (1.44 +/- 0.05 vs. 1.40 +/- 0.10); total percent weight gain (150 +/- 59% vs. 116 +/- 44%); or, feed conversion ratio (2.0 +/- 0.6 vs. 3.0 +/- 1.1). However, both diets proved inferior to the rotational diet for all of these factors. Lobsters fed the rotational diet had an average of 2.9 +/- 0.5 molts, weight gain ration per molt of 1.56 +/- 0.06, total percent weight gain of 376 +/- 67%, and a feed conversion ratio of 1.4 +/- 0.3. Lobsters fed feed B developed a whitish-blue exoskeleton after 4 - 5 wks, probably due to a carotenoid deficiency, so from day 58 onward, feed B was supplemented with carotenoid oil. The original exoskeleton color recovered after three molts. Lobster given feed B also seemed to take longer than those receiving feed A to harden the new exoskeleton after molting. Neither of the formulated feeds is adequate to replace the rotational diet.
Lin, Z. J., Li, J., Zhang, F. M., Song, S. Y., Yang, J., Liang, S. J., and Tsou, C. L. (1993). Structure of D-glyceraldehyde-3-phosphate dehydrogenase from Palinurus versicolor carrying the fluorescent NAD derivatives at 2.7 A resolution. Arch Biochem Biophys 302, 161-6.
Ultraviolet irradiation of carboxymethylated D-glyceraldehyde-3- phosphate dehydrogenase leads to the formation of a fluorescent NAD derivative. The structure of the enzyme from Palinurus versicolor carrying this derivative has been determined by molecular replacement and refined using the restrained least-squares method to 2.7 A with a final crystallographic R-factor of 0.205. The polypeptide chain folding and subunit arrangement closely resemble the known structure of Homarus americanus GAPDH. The structure at the modified active site confirms that the photochemical reaction is a half-of-the-sites reaction and occurs in the red and yellow subunit pair. The stereochemical relationship between the Trp residues at the active site shows that Trp 310 is most probably involved in a radiationless energy transfer to the fluorophore. A large solvent channel connecting the catalytic and NAD(+)-binding sites was found parallel to the crystallographic axis alpha from packing analysis, suggesting that this crystal form may be suitable for a kinetic crystallographic study of the apoenzyme.
Lin, C. Y., Chen, S. H., Kou, G. H., and Kuo, C. M. (1998). Identification and characterization of a hyperglycemic hormone from freshwater giant prawn, Macrobrachium rosenbergii. Comparative Biochemistry and Physiology a-Molecular and Integrative Physiology 121, 315-321.
Crustacean hyperglycemic hormone (CHH), a physiologically important neurohormone stored in the sinus gland of eyestalks, primarily regulates carbohydrate metabolism and also plays significant roles in reproduction, molting and other physiological processes. In the freshwater giant prawn, Macrobrachium rosenbergii, an injection of X-organ sinus gland (XOSG) extract evoked a hyperglycemic response, peaked in 1 h. The hyperglycemic effect of the eyestalk extract was maximal at the dose of 0.5 eyestalk equivalent. CHH fractionated by RP- HPLC, in M. rosenbergii was identified by its hyperglycemic activity and partial amino acid sequence, and the molecular weight of 8534 was determined by matrix-assisted laser desorption ionization mass spectrometry-time of flight analysis (MALDI-TOF). The amino acid sequence of the first 25 residues of CHH showed 72% homology with the first 25 residues of CHH A and CHH B of the American lobster Homarus americanus. (C) 1998 Elsevier Science Inc. All rights reserved.
Linnane, A., and Mercer, J. P. (1998). A comparison of methods for tagging juvenile lobsters (Homarus gammarus L) reared for stock enhancement. Aquaculture 163, 195-202.
The identification of cultured animals on recapture is an integral part of any modern stock enhancement programme. In lobster (Homarus sp.) release studies this is particularly taxing due to moulting, the small size of juveniles and costs. This work compares five tagging methods with respect to survival and tag retention over three moults. These consisted of internally placed tags, i.e., visible implant elastomer and coded microwire tags, two external marks, i.e., rostrum ablation and hot branding, and one external tag, i.e., the polyethylene streamer tag. A total of 1440 individuals were used in the study. Elastomer, microtags and rostrum ablations were applied to two age categories, i.e., 1.5 (5-8 mm carapace length (CL)) and 7 month (12-16 mm CL), brands were given to 7 and 9 month (16-19 mm CL) animals while streamer tags were given 9 month old individuals only. Older juveniles tagged abdominally with microtags and elastomer showed high survival (97%) and tag retention (99-100%). The younger age class also responded positively to microtags (83% survival and 96% tag retention) but survival was significantly reduced to 68%, with obvious tag migration, when this group were tagged with elastomer. To date, rostrum ablation proved to be a poor external mark with 100% of juveniles in both age classes successfully regenerating a rostrum within three moults. Survival of branded juveniles was size specific with levels of 57 and 90% for 7 and 9 month juveniles, respectively. Visibility of the mark faded with successive moults due to repigmentation in the exoskeleton. Lobsters tagged abdominally with streamer tags showed high survivorship (99%) and high tag retention (100%). Occasionally, this tag appeared to interfere with the moulting process and prolonged the time taken to shed the exoskeleton at ecdyses. Based on these findings, implantation of elastomer into juveniles less than 10 mm CL and branding of individuals less than 15 mm CL is not advised. Branding and ablation are not recommended for long term tagging studies. The internally placed tags, i.e., visible implant elastomer and microtags would appear to be more suitable options. (C) 1998 Elsevier Science B.V. All rights reserved.
Lipcius, R. N., Eggleston, D. B., Miller, D. L., and Luhrs, T. C. (1998). The habitat-survival function for Caribbean spiny lobster: an inverted size effect and non-linearity in mixed algal and seagrass habitats. Marine and Freshwater Research 49, 807-816.
The habitat-survival function (HSF) defines changes in survival relative to habitat structure; forms include linear, hyperbolic and sigmoid (threshold) curves, whose consequences on predator- prey dynamics are illustrated by their first derivatives. Survival of two juvenile size classes of Caribbean spiny lobster was evaluated as a function of plant biomass in tethering experiments in mixed algal and seagrass patches adjacent to Bahia de Ia Ascension, Mexico, which serves as nursery habitat. The HSF was hyperbolic for algal biomass; even modest increases of algal biomass significantly enhanced lobster survival. The rate of change in survival as a function of algal biomass (i.e. an approximation of the first derivative) was greatest at low-to-moderate levels of habitat structure. Hence, survival in these microhabitats is either low or rapidly changing with alterations in habitat structure, and they should be avoided by juveniles. Seagrass biomass did not significantly influence survival, although its levels were relatively low. Smaller juveniles had significantly higher survival rates than larger juveniles, probably because of the limited availability of appropriately scaled refugia for larger juveniles; large juveniles may display an ontogenetic shift from these habitats to coral reefs because of elevated predation risk as they grow.
Little, P. J., James, M. O., Foureman, G. L., Weatherby, R. P., and Bend, J. R. (1986). 1-14C-n-hexadecane disposition in the spiny lobster, Panulirus argus and the American lobster, Homarus americanus. J Environ Pathol Toxicol Oncol 6, 13-27.
1-14C-n-hexadecane, a model compound for the non-volatile aliphatic hydrocarbon components of crude oil, was administered by intrapericardial injection to the spiny lobster, Panulirus argus, and the clawed or American lobster, Homarus americanus. Experiments were conducted in Florida (spiny lobster) and Maine (American lobster). The animals were sacrificed at various times from 0.5 hr to 8 wks after administration of the dose. The tissues and fluids were analyzed for 14C content by digestion or catalytic oxidation and liquid scintillation counting. Selected tissues (hepatopancreas, tail muscle and hemolymph) were extracted with ethyl acetate to allow quantitation of the unmetabolized n-hexadecane by thin layer chromatography. n- Hexadecane-derived radioactivity was very persistent in both the spiny lobster (t1/2 = 4.6 wk) and the American lobster (t1/2 = 11.2 wk). In both lobsters, the hepatopancreas (HP) acquired the highest specific activity and the tail muscle had the longest half life for elimination from an individual tissue. Although hexadecane was metabolized more rapidly in the HP of the spiny lobster than in the HP of the American lobster, unmetabolized hexadecane persisted in the HPs of both species for at least 8 weeks after the dose (the longest time studied).
Liu, L., Laufer, H., Wang, Y. J., and Hayes, T. (1997). A neurohormone regulating both methyl farnesoate synthesis and glucose metabolism in a crustacean. Biochemical and Biophysical Research Communications 237, 694-701.
Methyl farnesoate (MF) has been identified as a juvenile hormone-like compound in crustacea which has central roles in the regulation of development and reproduction. To study the regulation of MF synthesis, we isolated a neuropeptide which inhibits MF synthesis from the neurohemal organ-sinus gland X- organ complex of the spider crab Libinia emarginata. The primary structure of this neuropeptide has been determined. It has 72 amino acid residues (deduced molecular mass 8490.5 Da) with pyroglutamic acid at the N-terminus and NH2 at the C- terminus. It shares a high percentage of sequence identity with other sinus gland neuropeptids which form the unique family of CHH neuropeptides of crustacea. Activity studies showed that this neurohormone has dual effects: it inhibited MF synthesis in vitro and had hyperglycemic activity when injected into crabs. (C) 1997 Academic Press.
Lnenicka, G. A., Blundon, J. A., and Govind, C. K. (1988). Early experience influences the development of bilateral asymmetry in a lobster motoneuron. Dev Biol 129, 84-90.
The development of functional asymmetry between a pair of homologous motoneurons of the claw closer muscles in lobsters, Homarus americanus, was studied. In juvenile lobsters, 3-5 years old, where the paired claws are highly specialized into a major (crusher) and minor (cutter) type, the fast closer excitor (FCE) motoneuron fired longer bursts of spikes in the crusher claw compared to those in its cutter counterpart. The intraburst impulse frequency was greater for the cutter FCE and its neuromuscular synapses showed greater facilitation at these high impulse frequencies compared to that of the crusher claw. However, such asymmetry in firing patterns and synaptic facilitation was absent in lobsters raised without a substrate and having paired cutter claws. In the earliest juvenile stage, synaptic facilitation was similar between the paired claws and then developed in either an asymmetric or symmetric manner depending on whether the lobsters experienced a substrate or not. In a substrate-free environment asymmetry could be produced by exercising one of the claws during development, implicating bilateral differences in the reflexive activity of the claws as a control mechanism.
Longyant, S., Sithigorngul, P., Thampalerd, N., Sithigorngul, W., and Menasveta, P. (1999). Monoclonal antibodies production specific to vitellin and vitellogenin of giant tiger prawn Penaeus monodon. Invertebrate Reproduction & Development 35, 9-17.
Monoclonal antibodies specific to Penaeus monodon vitellin and vitellogenin were produced using crude ovarian extract from gravid P. monodon ovaries. After immunization and fusion of mouse spleen cells with P3X myeloma, hybridomas were selected by indirect immunoperoxidase ELISA against P. monodon ovarian extract, followed by dot-blotting against native and denatured proteins from ovarian extract, female haemolymph, and male haemolymph. Four hybridoma clones producing antibodies (PMV-11, 15, 22 and 64) were identified. They bound with ovarian extract proteins and with female haemolymph, but not with male haemolymph. One antibody (PMV-64) bound with both native and denatured proteins. Using Western Blot analysis of ovarian extract separated by PAGE, all four monoclonal. antibodies bound with the same lipoglycoprotein band. Using Western Blot analysis of proteins separated by SDS-PAGE, PMV-64 antibody bound with Mw 80 and 83 kD proteins in ovarian extract, and with Mw 83 and 200 kD proteins in female haemolymph. All four monoclonal antibodies belong to the IgG1 subclass.
Luck, A., D'Haese, J., and Hinssen, H. (1995). A gelsolin-related protein from lobster muscle: cloning, sequence analysis and expression. Biochem J 305, 767-75.
The tail muscle of the lobster Homarus americanus contains an actin- binding protein with an apparent molecular mass of 105 kDa determined by SDS/PAGE and gelsolin-like properties. We isolated this protein and peptide sequences were obtained after limited proteolysis with chymotrypsin. A tail-muscle-specific cDNA library was constructed in a lambda expression vector and a full-length clone was obtained by screening with a polyclonal anti-(crustacean gelsolin) antibody. The cDNA insert of approx. 3.2 kb length was sequenced. The cDNA contained an open reading frame of 2.265 kb, and the deduced amino acid sequence of 754 residues (83,469 Da) identified the protein as a cytoplasmic member of the gelsolin/villin protein family. Comparison of the lobster gelsolin amino acid sequence with other members of this protein family revealed the characteristic 6-fold repeated segmental structure as well as the three conserved sequence motifs typical of each segment [Way and Weeds (1988) J. Mol. Biol. 203, 1127-1133]. Strong homologies were found with Drosophila gelsolin, human gelsolin, villin core, Dictyostelium severin and Physarum fragmin. In addition, the gelsolin- like protein from lobster muscle revealed motifs that were clearly similar to the actin-bundling region of human villin headpiece although it did not itself contain a distinct headpiece domain. The recombinant lobster gelsolin-like protein, expressed in Escherichia coli as a fusion protein, was purified from inclusion bodies and renatured as a functional protein. There were no significant differences in the biological activity tested between the recombinant and the native protein isolated from lobster muscle.
Lucu, C., and Devescovi, M. (1999). Osmoregulation and branchial Na+,K+-ATPase in the lobster Homarus gammarus acclimated to dilute seawater. Journal of Experimental Marine Biology and Ecology 234, 291-304.
Osmoregulatory ability and Na+,K+-ATPase activity in gills and epipodites were examined following transfer of the lobster Homarus gammarus from sea water (SW; 1292 mOsmol l(-1); 38 ppt salinity)to dilute seawater (DSW; 680+/-5 mOsmol l(-1;) .20 ppt salinity). The lobster H. gammarus behaves as an osmoconformer in sea water and a poor hyperosmoregulator when l(-1) above that of equilibrated in dilute seawater, where haemolymph was maintained 154 mOsmol l(-1) the medium. Lobsters could withstand direct transfer from SW to DSW and, after about 12 h, the initial drop in blood osmoconcentration and principal inorganic osmolytes ceased and a gradual increase followed during the next 15 days. Chloride and sodium were the main osmotic effecters responsible for the slow gradual adjustment of the blood hyperosmoticity. In DSW-acclimated lobsters, the Na+,K+-ATPase specific activities of gills (arthrobranchia and podobranchia) homogenates and partially purified membrane vesicle fractions were, respectively, 2.0 and 3.5 to 3.9-fold higher that those of the SW-acclimated animals. Enzyme specific activities of homogenate and membrane vesicle fractions isolated from DSW pleurobranchia were 1.4-fold higher than those of the SW-acclimated animals. In trichobranchiate gills and epipodites, saponin treatment increased the Na+,K+-ATPase activity over the native enzyme activity of the respective tissues. The plasma membrane vesicles from trichobranchiate gills and epipodites were better purified when isolated from DSW- than from SW-acclimated lobsters. Homogenates and membrane vesicles (enrichment factors ranging from seven to eight) from epipodites allowed a several-fold increase in enzyme specific activity over trichobranchiate gills. When lobsters were acclimated to DSW, the Na+,K+-ATPase specific activity measured in saponin-treated homogenates of epipodites was positively correlated with the sodium concentration gradient between haemolymph and DSW. The results suggest that epipodites Na+,K+- ATPase activation in DSW should be correlated with the blood sodium gradient, i.e. osmoregulatory ability. Short-circuit current of the hemiepipodite isolated from lobsters acclimated to DSW and mounted in a micro-Ussing chamber was - 232 mu A cm(-2) (negative charge flow driven from apical to basolateral side of preparation) and conductance was 65 mS cm(-2), a value characteristic of a leaky epithelium. Half-maximal inhibition of current by the specific Na+,K+-ATPase inhibitor ouabain occurs at 0.78 mM. At 1 mM ouabain, more then 70% of the inhibited current is Na+,K+-ATPase-related ion transport in epipodites. These results provide, for the first time, physiological evidence that, besides trichobranchiate gills, epipodites have an osmoregulatory role in the lobster Homarus gammarus. (C) 1999 Elsevier Science B.V. All rights reserved.
Lum, W. S., Wong, P. W., Yang, M. S., and Buttlaire, D. H. (1978). Spectrophotometric and fluorescence studies of the interaction of adenine nucleotides with arginine kinase of Homarus americanus. J Biol Chem 253, 6226-32.
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Ma, P. M., Beltz, B. S., and Kravitz, E. A. (1992). Serotonin-containing neurons in lobsters: their role as gain-setters in postural control mechanisms. J Neurophysiol 68, 36-54.
1. The electrophysiological properties of two pairs of identified serotonin-containing neurons in the fifth thoracic (T5) and first abdominal (A1) ganglia of the lobster, Homarus americanus, were studied with the use of intracellular recording methods. Intracellular dye injection combined with immunocytochemistry verified the neurochemical status of the recorded neurons. 2. The serotonin-containing neurons usually are spontaneously active at 0.5-1.0 Hz and produce large, overshooting action potentials with a prominent after- hyperpolarization. The action potentials appear to be generated by a pacemaking mechanism endogenous to the cells. Extracellular recordings from thoracic connectives and from second thoracic roots show that action potentials from the cells in A1 and T5 are propagated rostrally along their axons and invade axon collaterals that innervate neurohemal organs in the second thoracic roots and the pericardial organs. These observations suggest that these serotonin-containing cells may function in part as important neurosecretory cells in the lobster. 3. Members of the pairs of serotonin-containing cells are not synaptically connected. They receive prominent inhibitory inputs in the form of inhibitory postsynaptic potentials (IPSPs), which exhibit discrete size classes and probably arise from several sources. Most IPSPs are temporally synchronized among the two pairs of serotonin-containing cells. 4. The serotonin-containing cells respond to stimulation of postural command fibers, with flexion command fibers exciting and extension command fibers inhibiting the cells, suggesting that these cells are a part of the postural flexion circuitry. 5. Intracellular activation or inhibition of the serotonin-containing cells has no effect on the spontaneous readout of postural motor programs recorded from motor nerve roots. Coactivation of the serotonin-containing cells and command fibers, or inhibition of the serotonin-containing cells while activating command fibers, however, shows that the cells act as "gain- setters," modulating the interaction between command inputs and motoneuron outputs. 6. About 24% of the motor neuron units analyzed are influenced by the serotonin-containing cells. There is a bias toward facilitation of the readout of flexion motor programs, particularly with stimulation of strong and moderate flexion command fibers. 7. The serotonin-containing cells in T5 and A1 ganglia are hypothesized to serve two functions, one tonic and the other phasic, in modulating behavioral output in lobsters. Tonic firing of the cells should result in a sustained release of serotonin from central and peripheral sets of nerve terminals, which, in turn, could influence peripheral and central targets of the amine.(ABSTRACT TRUNCATED AT 400 WORDS).
Macmillan, D. L. (1975). A physiological analysis of walking in the American lobster (Homarus americanus). Philos Trans R Soc Lond B Biol Sci 270, 1-59.
The normal, unrestrained, forward walking of the lobster was studied with a closed-circuit television system and a video-tape recorder. A frame-by-frame analysis was undertaken and measurements made of unilateral stepping sequences, contralateral and ipsilateral phase relations between pairs of legs, the movements at the leg joints primarily involved in stepping and their differences in each of the four pereiopods. The order of stepping was expressed in terms of the probability of any leg following any other leg and it was found that while there is a preferred order, there is considerable variation from the dominant pattern. The commonest deviations from the dominant gait are those involving the simplest types of re-ordering of the sequence. Pairs of contralateral legs show a strong tendency to alternate but all phase relations can occur. Similarly, while the ipsilateral legs show preferred phase relations, all possible relations do occur. The four pereiopods from anterior to posterior were found to have respectively, a pulling action, a combined pulling and rowing action, a rowing action and a combined pushing and rowing action. The same parameters of stepping were recorded from animals walking on a transparent, driven treadmill and, as no significant differences were found in comparisons with results from freely moving animals, subsequent results were obtained from animals walking on the treadmill where more detailed study and manipulation could readily be made. The stepping action of the third pereiopod during forwards walking involves major movements about two joints whereas the other pereiopods move about three joints. Detailed study of the intra-leg activity was therefore confined to the third pereiopod where the simpler action considerably simplified the problems involved in collecting and analysing data. Measurements were made of the angles swept out by the joints of the third pereiopod during movement. Electromyograms were recorded from the six muscles primarily responsible for these movements and from movement transducers placed at the joints. The duration of the movements and of the bursts of acitivity in the muscles and the interrelation between different muscle bursts were measured and a computer-aided analysis made to determine the characteristic features of the inter-burst relations during stepping. While there is considerable variability from step to step, the overall activity is relatively phase-constant over a wide range of stepping frequencies. When some of the key parameters of normal walking had been characterized, changes designed to alter the sensory input to the system were imposed.
Macmillan, D. L., Neil, D. M., and Laverack, M. S. (1976). A quantitative analysis of exopodite beating in the larvae of the lobster Homarus gammarus (L.). Philos Trans R Soc Lond B Biol Sci 274, 69-85.
Raw data on exopodite beating in the first three developmental stages of the lobster Homarus gammarus were collected and analysed for key beating parameters. The analysis was computer assisted and the main procedures used are described. Beating patterns are the same in all three stages and are usually very regular although perturbations do occur (figures 1, 2). When beating stops the deceleration and subsequent re-acceleration is very rapid (figure 1) and limb movement sequences usually start posteriorly and move forwards (figures 1, 2d). Ipsilateral phase relations are generally maintained at 0.4-0.6 (figures, 3,4) and while the coupling between adjacent exopodites is usually stronger than for those further apart various deviations from this are occasionally seen (figure 5). No significant correlation between the ipsilateral phase relations of adjacent exopodites and base cycle duration was detected for any of the stages (figure 6). Contralateral phase relations undergo a constant progression (figures 7, 9) and this was found to be due to a heterodyne effect (figure 8) also described as gliding coordination. The powerstroke/returnstroke ratio for all stages was approximately 0.5 (figure 10) and no significant correlation was found with cycle duration (figure 11). The only substantial difference between the three larval stages which was noted was that of cycle duration, the cycles of stage III being shorter than those of the first two stages. The exopodite beating pattern was discussed in context with other metachronously cycling systems in arthropods and the implications of the present study discussed.
Macmillan, D. L. (1997). Development of the motor system in the limbs of larval lobsters (Homarus americanus). Biological Bulletin 193, 257-258.
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Magliozzo, R. S., Bubacco, L., McCracken, J., Jiang, F., Beltramini, M., Salvato, B., and Peisach, J. (1995). Cu(II) coordination in arthropod and mollusk green half-methemocyanins analyzed by electron spin-echo envelope modulation spectroscopy. Biochemistry 34, 1513-23.
Hemocyanin (Hc) is a dinuclear copper protein that binds oxygen reversibly. The structure of the Cu(II) site in a derivative of hemocyanin known as green half-met (GHM) has been analyzed using the pulsed EPR technique of electron spin-echo envelope modulation (ESEEM) spectroscopy. The derivative, prepared by treating the native protein with nitrite at low pH, contains a mixed-valent binuclear copper center. It was shown through chemical assays and the ligand exchange reaction products identified by EPR spectroscopy to contain a nitrite ligand bound to Cu(II). The ESEEM spectra of green half-methemocyanins from mollusks and arthropods indicated that three imidazole ligands are coordinated to Cu(II). Therefore, a tetragonal N3O ligand structure (O is an oxygen of nitrite) is proposed. For GHM Hc from the mollusks Octopus vulgaris and Rapana thomasiana, the isotropic nitrogen nuclear hyperfine coupling constant, aiso, for the N delta (or remote) nitrogen of two imidazoles was approximately 1.4 MHz, while for the third, aiso congruent to 2.2 MHz. The difference between the two weaker nitrogens and the single, more strongly coupled nitrogen was smaller by 0.2 MHz in the GHM Hcs from the arthropods Carcinus maenas, Homarus americanus and Panulirus interruptus. The nitrogen nuclear quadrupole coupling constants and asymmetry parameters, e2Qq and eta, for the N delta nitrogens in nearly all cases were near 1.4 MHz and 0.8, respectively, although Rapana thomasiana GHM Hc exhibited a reduction in eta that may indicate weaker hydrogen bonding in the active site of this protein. The g and ACu (copper nuclear hyperfine coupling) values for the derivatives, and the finding of three similar nuclear hyperfine coupling constants for the N delta sites of imidazole ligands, when considered with the orientation-specific information obtained using angle-selection methods for simulation of ESEEM spectra, suggest a distorted tetragonal Cu(II) structure in which three imidazoles and a nitrite ligand are bound near the equatorial plane. The finding that the two molluscan GHM Hcs exhibit differences associated with the remote nitrogen of imidazoles bound to Cu(II) may be related to a structural variability in the active sites of these proteins not found in the arthropodan GHM Hcs examined.
Malloy, S. C. (1978). Bacteria induced shell disease of lobsters (Homarus americanus). J Wildl Dis 14, 2-10.
Chitin degrading species of bacteria in the genera Pseudomonas, Vibrio, and Beneckea were cultured from the lesions of lobsters (Homarus americanus) with a shell disease. A species of bacterium of the genus Vibrio (Beneckea) produced necrosis characteristics of shell disease in experimental lobsters when the integument had been damaged prior to inoculation.
Marco, H. G., Brandt, W., and Gade, G. (1998). Elucidation of the amino acid sequence of a crustacean hyperglycaemic hormone from the spiny lobster, Jasus lalandii. Biochemical and Biophysical Research Communications 248, 578-583.
We have isolated a peptide from extracts of sinus glands of Jasus lalandii, a South African spiny lobster, by high- performance liquid chromatography (HPLC) and identified it as crustacean hyperglycaemic hormone (cHH) by (i) a conspecific bioassay measuring glucose elevation in the haemolymph and (ii) an immunoassay using an antiserum raised against cHH of the American lobster. The J. lalandii peptide has a free N-terminus as evidenced by sequencing the first 30 amino acid residues of the intact peptide. Further primary structural data were obtained from sequencing HPLC-purified tryptic and Asp-N proteolytic digests and by cyanogen bromide cleavage of the native, unreduced peptide. In this way, less than 400 sinus glands were used to provide the full sequence. Mass spectrometric analysis in conjunction with inferences based on interspecies sequence homology of cHH molecules unequivocally assigned the complete primary structure of cHH in a member of the crustacean infraorder Palinura for the first time. Our results show 51-76% homology with cHHs known from other decapod infraorders, the major difference being a free N-terminus and several amino acid substitutions interspersed in the non- conserved regions of the molecule. The J. lalandii cHH sequence presented here differs from a partial cHH sequence previously reported from allegedly the same species. (C) 1998 Academic Press.
Marco, H. G., and Gade, G. (1999). A comparative immunocytochemical study of the hyperglycaemic, moult-inhibiting and vitellogenesis-inhibiting neurohormone family in three species of decapod Crustacea. Cell and Tissue Research 295, 171-182.
Eyestalks of the palinuran species Jasus lalandii and Panulirus homarus, and the brachyuran species Carcinus maenas, were examined with antisera raised against purified crustacean hyperglycaemic hormone (cHH) of the astacidean species Homarus americanus and Procambarus bouvieri, as well as the brachyuran species Cancer pagurus. Other antisera used in this investigation were raised against purified moult-inhibiting hormone (MIH) of C. pagurus and vitellogenesis-inhibiting hormone (VIH) of H. americanus. Positive immunoreactions to all the antisera were localised in perikarya of the X-organ and the axon terminals in the sinus gland of all the crustaceans investigated. These results illustrate the existence of an immunological similarity, detectable at the immunocytochemical level, between the cHH/MIH/VIH neurohormones of the Astacidae, Palinura and Brachyura infraorders. Furthermore, results from consecutive tissue sections indicate that cHH, MIH and VIH are co-localised in a subpopulation of X-organ neurons.
Marco, H. G., and Gade, G. (1999). A comparative immunocytochemical study of the hyperglycaemic, moult- inhibiting and vitellogenesis-inhibiting neurohormone family in three species of decapod crustacea. Cell Tissue Res 295, 171-82.
Eyestalks of the palinuran species Jasus lalandii and Panulirus homarus, and the brachyuran species Carcinus maenas, were examined with antisera raised against purified crustacean hyperglycaemic hormone (cHH) of the astacidean species Homarus americanus and Procambarus bouvieri, as well as the brachyuran species Cancer pagurus. Other antisera used in this investigation were raised against purified moult- inhibiting hormone (MIH) of C. pagurus and vitellogenesis-inhibiting hormone (VIH) of H. americanus. Positive immunoreactions to all the antisera were localised in perikarya of the X-organ and the axon terminals in the sinus gland of all the crustaceans investigated. These results illustrate the existence of an immunological similarity, detectable at the immunocytochemical level, between the cHH/MIH/VIH neurohormones of the Astacidae, Palinura and Brachyura infraorders. Furthermore, results from consecutive tissue sections indicate that cHH, MIH and VIH are co-localised in a subpopulation of X-organ neurons.
Marder, E., Hooper, S. L., and Siwicki, K. K. (1986). Modulatory action and distribution of the neuropeptide proctolin in the crustacean stomatogastric nervous system. J Comp Neurol 243, 454-67.
Immunocytochemical methods were used to map the distribution of proctolinlike immunoreactivity in the stomatogastric nervous systems (stomatogastric ganglion (STG), paired commissural ganglia (CG), oesophageal ganglion (OG), and connecting nerves) of three crustacean species: Panulirus interruptus, Cancer borealis, and Homarus americanus. Although the patterns of proctolinlike staining were similar among the three species, some differences were also observed. Over 70% of the proctolinlike material in STGs, as measured by radioimmunoassay, was indistinguishable from authentic proctolin in reverse-phase high-performance liquid chromatography. Bath application of proctolin to STGs from Cancer and Panulirus induced characteristic and robust (though somewhat different) changes in their motor patterns. The threshold concentration was approximately 10(-9)M proctolin, and the effects were dose-dependent. These data suggest that the neuropeptide proctolin serves as a neuromodulator of the stomatogastric ganglion.
Marder, E., and Richards, K. S. (1999). Development of the peptidergic modulation of a rhythmic pattern generating network. Brain Res 848, 35-44.
The stomatogastric ganglion (STG) of adult lobsters and crabs receives dense aminergic and peptidergic projections. The neuropeptides are found in sensory neurons and in descending interneurons that modulate the output of the rhythmic central pattern generating networks in the STG. We describe the presence of these peptidergic projections in the adult Homarus americanus, and the effects of some of these neuropeptides on the motor patterns of the adult STG. We describe the developmental acquisition of these neuropeptides during embryonic and larval times and demonstrate that the immature STG networks are already sensitive to a variety of neuromodulators.
Marquis, J. K., and Webb, G. D. (1974). Studies of axon permeability utilizing axoplasm extrusion techniques with single isolated axons from the circumesophageal connectives of Homarus americanus. J Neurochem 23, 1085-6.
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Marquis, J. K. (1983). Properties of acetylcholinesterase in lobster axonal membrane. Comp Biochem Physiol C 74, 119-24.
1. Acetylcholinesterase (AChE) activity of axonal membrane vesicles prepared from lobster (Homarus americanus) walking leg nerve is about 200 mumol ACh/hr/mg protein. 2. The enzyme is a membrane-bound glycoprotein that can be solubilized by lysolecithin and digitonin but is rapidly inactivated by Triton X-100 and other nonionic detergents. 3. The walking leg nerve enzyme contrasts most markedly with postsynaptic AChE in its lack of inhibition by excess substrate and its poor susceptibility to peripheral anionic site ligands. 4. Axonal AChE is competitively blocked by eserine sulfate (1 microM) and by low concentrations of procaine (0.1-0.5 mM). 5. Lidocaine, a tertiary amine, and its quaternary ammonium derivative QX-314 are equipotent non- competitive enzyme inhibitors (Kiapp 2-3 mM), while the primary amine compound GX-HCl is totally inactive. 6. Calcium (10 50 mM), propidium (1 microM) and decamethonium (1 microM), peripheral anionic site ligands in the synaptic enzyme, do not protect the axonal enzyme against inhibition by local anesthetics. 7. Although it is possible that this enzyme is an isozyme of the true AChE of excitable membranes, or that it is an incomplete enzyme fragment, it is also possible that there is a unique membrane-bound AChE present in large quantities in crustacean peripheral nerve.
Martin, G. G., Kay, J., Poole, D., and Poole, C. (1998). In vitro nodule formation in the ridgeback prawn, Sicyonia ingentis, and the American lobster, Homarus americanus. Invertebrate Biology 117, 155-168.
Bacteria injected into the hemolymph of crustaceans are rapidly cleared from circulation; many accumulate in the gills, even though this organ does not contain fixed phagocytic cells. In this study, hemolymph from a shrimp or a lobster was mixed in a culture medium with or without bacteria. In all cases, hemocytes rapidly aggregated to form nodules. As nodules increased in size, the number of free hemocytes, nodules, and bacteria (if present) decreased. Nodule formation was inhibited by the addition of the peptide RGD (Arg-Gly-Asp). The morphology of the nodules formed in the presence and absence of bacteria was examined using light and electron microscopy. Within 10 min, nodules were larger than the small blood spaces of the gills, suggesting that in vivo clearance is the result of physical entrapment of nodules and foreign material in the narrow vessels of the gills. This method of removing foreign material from circulation is discussed in relation to other clearing mechanisms in crustaceans.
Martin, G. G., Lin, H. M. J., and Luc, C. (1999). Reexamination of hemocytes in brine shrimp (Crustacea, Branchiopoda). Journal of Morphology 242, 283-294.
In 1941, a single type of hemocyte was described in the blood of the brine shrimp Artemia salina using light microscopy.! This condition is unusual because most crustaceans examined using morphological, cytochemical, and functional methods have at least two types of hemoctyes. Upon examining A. franciscana, we found a single type of disk-shaped hemocyte, with a centrally located nucleus and about 15 large (6 mu m diameter) granules. The: granules stain for the presence of acid phosphatase: and react with L-D OPA suggesting, respectively, that they are involved in degrading ingested material and possess the phenoloxidase system. Hemocytes: require calcium for adhesion, bind together to mend small wounds in the body wall, and are able to phagocytose bacteria. Blood cells of A. franciscana are; morphologically and functionally similar to those of the primitive chelicerate, Limulus polyphemus, and both forms have apparently given rise to, more advanced taxa with multiple types of hemocytes. The major difference,between the two species is the presence of the phenoloxidase system in the Crustacea and its apparent absence in the chelicerates. (C) 1999 Wiley-Liss, Inc.
Martin, G., Sorokine, O., Moniatte, M., Juchault, P., and Van Dorsselaer, A. (1999). Profiling the peptides in two neurohemal organs, the sinus gland and lateral nervous plexus of terrestrial isopods (Crustacea), by mass spectrometry. Canadian Journal of Zoology-Revue Canadienne De Zoologie 77, 1300-1308.
A comparison was made of the ultrastructure of two neurohemal organs: the sinus gland and the lateral nervous plexus of the Oniscidea (Crustacea). Reverse-phase chromatography clearly showed that the two organs contain different neuropeptides. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry proved to be an efficient tool for detecting the molecules stored in a single freshly dissected neurohemal organ. All the results combined lead us to emphasize that the sinus gland of Oniscidea stores mainly crustacean hyperglycemic hormone (CHH) and vitellogenin-inhibiting hormone; these two hormones were not characterized in the lateral nervous plexus (LNP). Smaller peptides and other molecules of the CHH family might be released by the LNP in the vicinity of the Y-organ (the ecdysteroid-producing gland).
Massabuau, J. C., and Meyrand, P. (1996). Modulation of a neural network by physiological levels of oxygen in lobster stomatogastric ganglion. J Neurosci 16, 3950-9.
Although a large body of literature has been devoted to the role of O2 in the CNS, how neural networks function during long-term exposures to low but physiological O2 partial pressure (PO2) has never been studied. We addressed this issue in crustaceans, where arterial blood PO2 is set in the 1-3 kPa range, a level that is similar to the most frequently measured tissue PO2 in the vertebrate CNS. We demonstrate that over its physiological range, O2 can reversibly modify the activity of the pyloric network in the lobster Homarus gammarus. This network is composed of 12 identified neurons that spontaneously generate a triphasic rhythmic motor output in vitro as well as in vivo. When PO2 decreased from 20 to 1 kPa, the pyloric cycle period increased by 30- 40%, and the neuronal pattern was modified. These effects were all dose- and state-dependent. Specifically, we found that the single lateral pyloric (LP) neuron was responsible for the O2-mediated changes. At low PO2, the LP burst duration increased without change in its intraburst firing frequency. Because LP inhibits the pyloric pacemaker neurons, the increased LP burst duration delayed the onset of each rhythmic pacemaker burst, thereby reducing significantly the cycling frequency. When we deleted LP, the network was no longer O2-sensitive. In conclusion, we propose that (1) O2 has specific neuromodulator-like actions in the CNS and that (2) the physiological role of this reduction of activity and energy expenditure could be a key adaptation for tolerating low but physiological PO2 in sensitive neural networks.
Mattisson, A. G. (1965). The localisation of succinic dehydrogenase in the muscles of Nereis Virens and Homarus Gammarus. Histochemie 5, 97-115.
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Mayes, J. I., and Govind, C. K. (1989). Higher mitochondrial density in slow versus fast lobster sensory neurons. Neurosci Lett 102, 87-90.
The stretch-sensitive muscle receptor organ (MRO) in the abdomen of the lobster Homarus americanus contains an identifiable fast and a slow sensory neuron. Morphometric analysis of electron micrographs of areas through the somata of these neurons revealed a higher density of mitochondria in the slow versus the fast cell (19 vs 15%). Such differences in oxidative capacity are closely matched with differences in their physiological performances.
Maynard, D. M., and Dando, M. R. (1974). The structure of the stomatogastric neuromuscular system in Callinectes sapidus, Homarus americanus and Panulirus argus (Decapoda Crustacea). Philos Trans R Soc Lond B Biol Sci 268, 161-220.
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McBride, W. J., Freeman, A. R., Graham, L. T., Jr., and Aprison, M. H. (1975). Content of amino acids in axons from the CNS of the lobster. J Neurobiol 6, 321-8.
The contents of alanine, proline, glycine, GABA, glutamate, and aspartate were measured in four bundles of axons (designated areas A through D) from the circumesophageal connective of the lobster (Homarus americanus). The contents of these amino acids were also determined in individual axons within specific bundles and in the external sheath covering the circumesophageal connective. Within the nerve bundles the levels of aspartate were highest of the amino acids measured, ranging from 1.95 +/- 0.12 mumol/mg protein in area C to 7.55 +/- 0.54 mumol/mg protein in area B. On the other hand, GABA had the lowest value in the four bundles; its highest level was found in area C (0.083 +/- 0.006 mu mol/mg protein) and the lowest in area B (none detected). The content of glycine ranged from 1.63 +/- 0.14 (area C) to 2.52 +/- 0.32 mumol/mg protein in area A; that for glutamate ranged from 0.390 +/- 0.019 (area C) to 1.01 +/- 1.03 (area B). The contents of alanine and proline changed relatively little from bundle-to-bundle. The content of aspartate was the highest of any of the amino acids assayed in individual axons (with diameters in the range of 40 to 65 mu) dissected from areas B and C. Glycine had the next highest content followed in order by glutamate, proline, and alanine. GABA was not detected in these axons. With the exception of GABA (which could not be detected), aspartate had the lowest level (0.066 +/- 0.017) and glycine had the highest level (2.00 +/- 0.498 mumol/mg protein) in the external sheath covering the the circumesophageal connective.
McCarthy, J. F., Sastry, A. N., and Tremblay, G. C. (1976). Thermal compensation in protein and RNA synthesis during the intermolt cycle of the American lobster, Homarus americanus. Biol Bull 151, 538-47.
1. The in vitro rates of incorporation of precursors into protein and RNA and the concentration of RNA were measured in tissues of intermolt and premolt lobsters acclimated to 5 degrees C and 20 degrees C. Midgut gland, abdominal muscle and gill of intermolt lobsters respond to temperature acclimation by a compensatory translation of the rate- temperature (R-T) curves with respect to the rates of incorporation of 3H-leucine and 3H-uridine into the acid-insoluble fraction. Midgut gland and muscle of premolt animals exhibit either no compensation or inverse compensation; gill tissue exhibits a rotation of the R-T curve. 2. The existence of the complete de novo pathway of pyrimidine biosynthesis is demonstrated in the class Crustacea. NaH14 CO2 is incorporated into orotic acid and orotic-14 C-acid is incorporated into the acid-insoluble fraction. 3. Both the concentration of RNA and the rates of incorporation of precursors of both the salvage and de novo pyrimidine pathways are enhanced in the midgut gland of premolt lobsters, relative to intermolt tissue, under conditions of warm- acclimation.
McClintock, T. S., Xu, F., Quintero, J., Gress, A. M., and Landers, T. M. (1997). Molecular cloning of a lobster G alpha(q) protein expressed in neurons of olfactory organ and brain. J Neurochem 68, 2248-54.
We have isolated from an American lobster (Homarus americanus) olfactory organ cDNA library a clone, hG alpha(q), with >80% identity to mammalian and arthropod G alpha(q) sequences. In brain and olfactory organ, hG alpha(q) mRNA was expressed predominantly in neurons, including virtually all the neuronal cell body clusters of the brain. G alpha(q) protein was also expressed broadly, appearing on western blots as a single band of 46 kDa in brain, eyestalk, pereiopod, dactyl, tail muscle, olfactory organ, and aesthetasc hairs. These results suggest that hG alpha(q) plays a role in a wide variety of signal transduction events. Its presence in the olfactory aesthetasc hairs, which are almost pure preparations of the outer dendrites of the olfactory receptor neurons, the expression of a single hG alpha(q) mRNA species (6 kb) in the olfactory organ, and the localization of hG alpha(q) mRNA predominantly in the olfactory receptor neurons of the olfactory organ strongly suggest that one function of hG alpha(q) is to mediate olfactory transduction.
McConnell, C. J., DeMont, M. E., and Wright, G. M. (1997). Microfibrils provide non-linear elastic behaviour in the abdominal artery of the lobster Homarus americanus. J Physiol (Lond) 499, 513-26.
1. Microfibrils are becoming increasingly recognized as an important component of the extra-cellular matrix. However, almost nothing is known about their mechanical role in the diversity of tissues in which they are found. 2. Microfibrils form the principal structural component in the wall of the abdominal artery of the lobster Homarus americanus. We have used previous estimates of the mechanical properties of these microfibrils, estimates of the fraction of the aorta wall volume occupied by the microfibrils, and their angular distribution as a function of strain in a numerical model that predicts the macroscopic mechanical properties of the whole tissue. 3. Microfibrils alone, when their reorientation and deformation are accounted for, characterize the stress-strain behaviour of the vessel. Evidence of the evolutionary conservation of fibrillin between medusans, echinoderms and vertebrates implies that the mechanical properties of lobster microfibrils may apply to microfibrillar function in other taxa. This will have profound implications on the perceived roles of microfibrils in development, physiology and disease.
McHenery, J. G., LinleyAdams, G. E., Moore, D. C., Rodger, G. K., and Davies, I. M. (1997). Experimental and field studies of effects of dichlorvos exposure on acetylcholinesterase activity in the gills of the mussel, Mytilus edulis L. Aquatic Toxicology 38, 125-143.
Dichlorvos (DDVP) is an organophosphate medicine, used to treat ectoparasitic sea lice infestations of farmed salmon. Effects of this chemical on a non-target organism were investigated. Experimental exposure of mussels (Mytilus edulis L.) to dichlorvos (DDVP) resulted in changes in gill acetylcholinesterase (AChE) activity with a hermetic increase at lower concentrations, and 50% inhibition at 3.6 mu g l(-1) after 24 h exposure. Repeat exposures resulted in cumulative inhibition. Twenty-four hour exposure to DDVP impaired the ability to close shells (EC50 of 1700 mu g l(-1)) and caused mortalities at high concentrations (LC50 of 8200 mu g l(-1)). AChE levels in mussels collected from sea lochs were indicative of DDVP inhibition related to the quantities of DDVP used. The use of AChE as a sublethal indicator of DDVP usage in the field is discussed. Crown Copyright (C) 1997 Published by Elsevier Science B.V.
McKenney, C. L., Weber, D. E., Celestial, D. M., and MacGregor, M. A. (1998). Altered growth and metabolism of an estuarine shrimp (Palaemoaetes pugio) during and after metamorphosis onto fenvalerate-laden sediment. Archives of Environmental Contamination and Toxicology 35, 464-471.
Dry weight (W), carbon (C), nitrogen (N), and energy (E) (calculated) accumulation were measured in the estuarine grass shrimp, Palaemonetes pugio, throughout larval development and during the first 2 weeks as postlarvae in seawater over sediment containing the pyrethroid insecticide fenvalerate (SCF; nominal concentrations of 1, 10, and 100 mu g fenvalerate kg(-1) sediment). The influence of fenvalerate-laden sediment on shrimp growth and utilization patterns of C, N, and E was dependent on fenvalerate concentration, age of shrimp, and whether shrimp were premetamorphic or postmetamorphic in development. The fenvalerate concentration in the sediment, which ultimately inhibited larval metamorphosis (100 mu g fenvalerate kg(-1) sediment), significantly reduced W accumulation in developing larvae and in postlarvae growing on the sediment for an equivalent time. Accumulation of C, N, and E varied not only with concentration of SCF, but differed between pelagic larvae developing in water above SCF and newly settled postlarvae growing in direct contact with SCE Larvae developing above greater than or equal to 10 mu g kg(-1) SCF contained significantly less N, while postlarval shrimp settling onto greater than or equal to 10 mu g kg(-1) SCF accumulated significantly less C and E. Measurable variations in growth and energy reserves of toxicant-sensitive life stages in response to environmentally realistic insecticide exposures have a direct link to ecological consequences of toxic stress and may be useful as biomarkers to diagnose early damage in estuarine populations.
McLaughlin, L. C., Walters, J., Atema, J., and Wainwright, N. (1999). Urinary protein concentration in connection with agonistic interactions in Homarus americanus. Biological Bulletin 197, 254-255.
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McLeese, D. W., Metcalfe, C. D., and Pezzack, D. S. (1980). Bioaccumulation of chlorobiphenyls and endrin from food by lobsters (Homarus americanus). Bull Environ Contam Toxicol 25, 161-8.
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Meiss, D. E., and Govind, C. K. (1980). Heterogeneity of excitatory synapses at the ends of single muscle fibers in lobster, Homarus americanus. J Neurobiol 11, 381-95.
Crustacean neuromuscular synapses arising from a single excitor axon are known to be well differentiated among different muscle fibers but little is known about their condition along single fibers. Focal recording techniques were used to examine the quantal transmitter release and facilitation properties of synapses in the single excitatory innervated distal accessory flexor muscle of the lobster, Homarus americanus. Synapses were reliably differentiated with respect to quantal output so that those located near the tendon end were 1.15-- 4.12 times greater than those at the opposite, exoskeletal end (p less than 0.01, paired t-test). Regional differences were also seen in the amount of facilitation determined from twin pulse experiments. The fine structural basis for these differences was determined by serial section electron microscopy of 10-micrometer segments at each end to ensure that the area of focal recording was sampled. No quantitative differences were found in the terminals or synapses in the two regions. Instead, the physiological diversity was correlated with number and size of presynaptic dense bars. Thus, the tendon end had a greater number and larger mean surface area of dense bars compared to the exoskeletal end. This heterogeneity of excitatory multiterminal innervation is correlated with the axonal branching pattern. Thus, the main axon and the larger primary axon branches lie in close proximity to the tendon end of the muscle fibers, whereas the exoskeletal end is innervated by smaller secondary and tertiary axonal branches. This proximity to the large axonal branches of the higher quantal output synapses at the tendon end may be regulated by some neural influence including a timing of innervation and/or access to greater amounts of metabolites in the larger branches which may be conducive to forming high-output synapses.
Mello, J. J., Cromarty, S. I., and Kass-Simon, G. (1999). Increased aggressiveness in gravid American lobsters, Homarus americanus. Aggressive Behavior 25, 451-472.
Reports in the literature suggest that gravid female lobsters (Homarus americanus) are more aggressive than non-gravid female lobsters. In an earlier study [Cromarty SI et al. 1998. Biol Bull 194:63-71], we showed that, with one exception, gravid females did not respond to an unfamiliar stimulus with escape swimming. Here we present quantitative evidence showing that gravid female lobsters are more aggressive than non-gravid females. Gravid and non-gravid females were allowed to fight against larger, non-gravid female opponents in an enclosed arena. The videotaped behaviors were ranked in a behavioral hierarchy (Rank of Aggression) according to their degree of aggressiveness and intensity. The behaviors were classified and ranked as follows: (1) aggression toward opponent, (2) redirected aggressive behavior (toward arena wall), (3) redirected defensive behavior, (4) defensive behavior against opponent, and (5) avoidance behavior. Gravid lobsters performed more behaviors and more aggressive behaviors than did non- gravid controls. The behaviors of gravid females ranked higher on the Rank of Aggression scale than did non-gravid females. The opponents of gravid females performed more aggressive and more intensely aggressive acts than the opponents of non-gravid females; they also performed more defensive acts (i.e., those used to ward off an opponent's attack) than did their non- gravid opponents, although there were no differences in intensity of defensive behaviors between gravid and non-gravid animals. There were no significant differences in the number of avoidance behaviors among the four types of combatants (gravid, non-gravid, gravid opponent, and non-gravid opponent), and none in avoidance tailflipping. However gravid females were more likely to perform aggressive tailflips and performed significantly more aggressive tailflips than non-gravid animals. Together, this suggests that any physiological inhibition of escape swimming may have been overcome by the heightened intensity of gravid fights and the increased aggressiveness of gravid animals. (C) 1999 Wiley-Liss, Inc.
Menze, M., Hellmann, N., Decker, H., and Grieshaber, M. K. (1999). Comparison of ligand binding behaviors in heamocyanin of Homarus vulgaris as determine by ITC or UC. Biophysical Journal 76, A111-A111.
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Meusy, J. J., Martin, G., Soyez, D., van Deijnen, J. E., and Gallo, J. M. (1987). Immunochemical and immunocytochemical studies of the crustacean vitellogenesis-inhibiting hormone (VIH). Gen Comp Endocrinol 67, 333-41.
Immunochemical investigations, using dot immunobinding assay (DIA) and enzyme-linked immunosorbent assay (ELISA), and immunocytochemical studies reveal the following new information about crustacean vitellogenesis-inhibiting hormone (VIH): (1) The structure of VIH is sufficiently different from that of the other sinus gland neuropeptides to allow a selective recognition of VIH by polyclonal antibodies. (2) From immunochemical criteria, VIH does not seem strictly species specific. The antisera raised against VIH of Homarus americanus cross- react with sinus gland extracts of Palaemonetes varians, Palaemon serratus, Macrobrachium rosenbergii, Carcinus maenas, and Porcellio dilatatus. (3) In the sinus gland of H. americanus, VIH immunoreactivity is localized mainly in electron-dense granules of medium size (110-185 nm in diameter) while, in P. dilatatus, the labeling is mostly on the largest granules (200-270 nm in diameter).
Meusy, J. J., and Soyez, D. (1991). Immunological relationships between neuropeptides from the sinus gland of the lobster Homarus americanus, with special references to the vitellogenesis inhibiting hormone and crustacean hyperglycemic hormone. Gen Comp Endocrinol 81, 410-8.
Antisera raised in guinea pigs against four major neuropeptides purified from sinus glands of the lobster, Homarus americanus, were used to study the immunological relationships between several sinus gland peptides. On the basis of their behavior in ELISA and in absorption procedures, three groups of peptides are defined. Two groups may be related to the crustacean hyperglycemic hormone (CHH groups); the third one is composed of three immunologically identical peptides and, since one of these peptides was characterized in previous studies as a vitellogenesis inhibitor, is referred to as VIH group. This closely meets our present knowledge about the physiological effects and biochemical characteristics of these neuropeptides and gives immunological insights on the question of molecular polymorphism of lobster neurohormones.
Meyrand, P., Simmers, J., and Moulins, M. (1994). Dynamic construction of a neural network from multiple pattern generators in the lobster stomatogastric nervous system. J Neurosci 14, 630-44.
In the stomatogastric nervous system (STNS) of the lobster Homarus gammarus, the rhythmic discharge of a pair of identified modulatory neurons (PS cells) is able to construct de novo a functional network from neurons otherwise belonging to other functional networks. The PS interneurons are electrically coupled and possess endogenous oscillatory properties that can be activated synaptically by stimulation of an identified sensory pathway. PS neurons themselves project synaptically onto the three major neural networks (esophageal, gastric mill, and pyloric) of the STNS. When a PS is rhythmically active in vitro, either spontaneously (rarely) or in response to direct stimulation, it dramatically restructures the otherwise independent activity patterns of all three target networks. This functional reconfiguration elicited by a single cell does not rely on changes in neuronal allegiance to pre-existing circuits, or on a simple merger of these different circuits. Rather, PS is responsible for the creation of an entirely new motor rhythm in that, via its widespread synaptic connections, the interneuron is able to subjugate the ongoing activity of the three STNS circuits and selectively appropriate individual elements to its own intrinsic rhythm. In addition, PS excites motor neurons that innervate dilator muscles of a valve situated between the esophagus and the stomach. The reorganization of the regional foregut motor rhythms by the interneuron is therefore coordinated to the opening of this valve, which itself carries sensory receptors that have been found to activate bursting in PS. Our data suggest that the role of PS in massively restructuring stomatogastric output is to generate a unique motor pattern appropriate for swallowing-like behavior. In a wider context, moreover, the results demonstrate that a neural network may not exist as a predefined entity within the CNS, but may be dynamically assembled according to changing behavioral circumstances.
Miller, M. W., and Sullivan, R. E. (1981). Some effects of proctolin on the cardiac ganglion of the Maine Lobster, Homarus americanus (Milne Edwards). J Neurobiol 12, 629-39.
The neuropeptide proctolin has excitatory effects on the isolated lobster cardiac ganglion. Selective application to the anterior cell body region produces a dose-dependent (10(-8)--10(-5) M) prolonged depolarization of large anterior cells as well as marked increases in burst frequency and/or duration. In ganglia which have been silenced with tetrodotoxin, proctolin application to anterior cells elicits long- lasting depolarizing responses which are accompanied by a 10-30% increase of the apparent membrane input resistance. Higher proctolin concentrations produce high-frequency trains of driver potentials. It is proposed that a proctolin like peptide may serve a neurohumoral role in the lobster cardiac ganglion and that the anterior motor neurons exhibit endogenous rhythmicity in its presence.
Miller, D. S., and Holliday, C. W. (1987). Organic cation secretion by Cancer borealis urinary bladder. Am J Physiol 252, R153-9.
In the crab, Cancer borealis, initial clearance studies showed a potent renal excretory system for the model organic cation, tetraethylammonium (TEA). TEA clearance averaged 145 +/- 32 ml/day, which was 18 times the paired polyethylene glycol clearance. TEA uptake by slices of urinary bladder was concentrative, saturable, inhibitable by N1- methylnicotinamide chloride, and dependent on glycolytic, but not oxidative, metabolism. When mounted in flux chambers, bladders exhibited a large net secretory flux. For 0.1 mM TEA, the ratio of secretory to reabsorptive fluxes was 65. Urinary bladders from another crab, Cancer irroratus, and a lobster, Homarus americanus, also exhibited net TEA secretion. In C. borealis bladder, secretory transport was concentrative, saturable, and nearly abolished by addition of 1 mM quinine to the serosal bath. Reabsorptive transport was not concentrative and was not reduced by luminal quinine. The data are consistent with a secretory pathway that is transcellular and mediated by carriers at both the serosal and luminal membranes.
Miller, R. J. (1997). Spatial differences in the productivity of American lobster in Nova Scotia. Canadian Journal of Fisheries and Aquatic Sciences 54, 1613-1618.
Lobster production per unit area of habitat varies greatly from location to location. Several physical and biological variables have previously been offered as explanations. In this study the density of ovigerous females (a proxy for egg production), postlarvae, and recruits to the fishery were measured in seven adjacent areas spanning 190 km of Nova Scotia coast. The ranking of these densities among areas persisted from year-to- year, showing consistent spatial differences in productivity. A high spatial correlation between postlarvae and fishery recruits implicated postlarvae as the proximate regulator of lobster yields. Further correlation showed that egg to postlarval survival, and not egg abundance, was related to fishery recruits. Implications for fishery management are (i) enhancement of any life-history stage between postlarvae and fishery recruits should increase fishery yields and (ii) very different levels of egg production may be necessary to maintain an equal level of fishery recruits among areas. Larval survival was highest in areas where hatching occurred late in the season; this differs from previous suggestions that early hatching promotes survival.
Miron, G., Boudreau, B., and Bourget, E. (1999). Intertidal barnacle distribution: a case study using multiple working hypotheses. Marine Ecology-Progress Series 189, 205-219.
The roles of larval supply, selection of habitat, availability of space, larval physiological condition, and early post- settlement mortality in determining vertical distribution patterns of the barnacle Semibalanus balanoides (L.) were simultaneously examined in Passamaquoddy Bay, New Brunswick, Canada. Pump samples and settlement surveys showed that about 60% of planktonic cyprids were collected from 1.5 to 4.0 m depth, while over 90 % of newly settled cyprids colonized low intertidal levels. Selection of habitat by cyprids and patterns of settlement were studied using precolonized planks that had been previously placed to obtain various periphyton gradients. These planks precolonized at the low, mid-, and high intertidal levels and placed in different orientations, induced variations in the distribution of newly settled cyprids. For example, vertical planks turned upside down had fewer settlers at low intertidal levels compared to surfaces maintained in the same orientation at the same level. When placed horizontally at the same level, sections precolonized at the low intertidal level collected more larvae than sections initially placed at the high and mid-intertidal levels. We used the triacylglycerol/cholesterol ratio (TAG/CHOL) as a measure of physiological condition in planktonic and newly settled cyprids, and newly metamorphosed spat. The TAG/CHOL ratio in planktonic cyprids decreased over the sampling period, but there was no variability with position in the water column. For newly settled cyprids and newly metamorphosed spat, the TAG/CHOL ratio increased with decreasing intertidal level. Quadrats freed of conspecific adults were colonized by more cyprids than were uncleared controls. Early post-settlement mortality was greater in uncleared than in cleared quadrats, but this effect varied with intertidal level. Early post- settlement mortality increased with increasing intertidal level in cleared quadrats, while it did not significantly vary in uncleared controls. The present study shows that the Vertical distribution of S. balanoides on the shore results from a complex relation ship involving larval supply, selection of habitat, availability of space, and early post-settlement mortality. We also present the first evidence of correlations between larval physiological condition and early vertical distribution in S, balanoides.
Mjos, K., Grasso, F., and Atema, J. (1999). Antennule use by the American lobster, Homarus americanus, during chemo-orientation in three turbulent odor plumes. Biological Bulletin 197, 249-250.
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Mohan, R. (1997). Size structure and reproductive variation of the spiny lobster Panulirus homarus over a relatively small geographic range along the Dhofar coast in the Sultanate of Oman. Marine and Freshwater Research 48, 1085-1091.
This paper reports variations in size structure, size at sexual maturity, and reproductive potential in the Panulirus homarus population sampled from commercial catches at three sites: Shuwamiyah, Sudh and Mugsyl along the Dhofar coast in the Sultanate of Oman. The size structure of the lobster population showed significant variation (P < 0.001) among the three sites. Size at sexual maturity, based on the presence of spermatophores or an ovigerous condition, indicated variation within the population. Females mature at a smaller size at Shuwamiyah than they do at Sudh and Mugsyl. The relationship between the number of eggs (E) and carapace length (L, in mm) of female lobsters is expressed by E = -249322 + 8942L (r(2) = 0.95; n = 11) over the size range 65-95 mm carapace length. Length frequency, size at sexual maturity, and fecundity were used to estimate the index of reproductive potential (IRP) of each 5-mm size class. The size class with the highest IRP varied among the three sites. The variation in size structure and size at sexual maturity was explained by fishery exploitation and by different oceanographic and ecological conditions caused by seasonal upwelling in the study region.
Moksnes, P. O., Pihl, L., and van Montfrans, J. (1998). Predation on postlarvae and juveniles of the shore crab Carcinus maenas: importance of shelter, size and cannibalism. Marine Ecology-Progress Series 166, 211-225.
Settlement and early juvenile stages are considered a bottleneck in the Life history of many epibenthic organisms because of high predation mortality. Nursery habitats may play an important role in mitigating settlement and post-settlement mortality by providing refuge from predation. We examined these relationships in postlarvae and early juvenile stages of the shore crab Carcinus maenas L. in laboratory and field tethering experiments. We studied habitat and size related habitat mortality using postlarvae and young juvenile crabs as prey, and various predators, including juvenile conspecifics, in several habitats common in shallow (0 to 1 m) soft bottom nursery areas on the Swedish west coast. Settling mortality was high in open sand (80 to 90%), whereas a significant habitat refuge was obtained in mussel beds, eelgrass and filamentous green algae, the latter yielding the lowest mortality (13 to 14%). Small differences in structural complexity of ephemeral macroalgae dramatically affected predation mortality of first instar crabs, with a significant refuge obtained only in algae of medium complexity. Predation rate on tethered crabs in the field was high (52 to 67%) only on the smallest crabs (<5 mm carapace width, CW), which obtained a significant refuge in the eelgrass habitat compared to open sand. Mortality for larger crabs (5 to 25 mm CW) was low (<10%) and similar in sand and eelgrass habitats. Our results indicate that predation is an important process that can create a bottleneck for juvenile shore crab populations during settlement and early juvenile stages, mediated by the availability of nursery habitats. Postlarvae obtained refuge from predation in several different habitats, suggesting that the recruitment of juvenile shore crabs will be less affected by temporal and spatial variation of any single habitat type. The strong size refuge for crabs larger than 4 mm CW indicates that key predators are small. We suggest that cannibalistic juveniles, which caused predation rates similar to or higher than all other investigated predators, are dominant predators on settling postlarvae and young juvenile crabs in nursery areas. We further propose that habitat- and size-specific predation by small epibenthic predators are an important selective force in habitat selection by postlarvae and ontogenetic shifts in habitat use by juveniles.
Moksness, E., Stole, R., and van der Meeren, G. (1998). Profitability analysis of sea ranching with Atlantic salmon (Salmo salar), Arctic charr (Salvelinus alpinus), and European lobster (Homarus gammarus) in Norway. Bulletin of Marine Science 62, 689-699.
The Norwegian Sea Ranching Program (PUSH, acronym for Program for Utvikling og Stimulering av Havbeite) was started in 1990 and is scheduled to terminate by the end of 1997. The program has focused on four species: Atlantic salmon (Salmo salar), Arctic charr (Salvelinus alpinus), cod (Gadus morhua), and European lobster (Homarus gammarus), with the main objective of examining both the biological and economic basis for sea ranching. In the present study, profitability analyses have been conducted by the net present value (NPV) method and application of available data :ti om a research program. From the results, we conclude that sea ranching of Arctic charr will not be economically profitable at the present juvenile costs, recapture rate, and market price and that this conclusion is unlikely to change in the near future. For Atlantic salmon the activity will be profitable only if the present recapture rate more than doubles, to approximately 10%. On the basis of the present juvenile cost, recapture rate, and market price for European lobster, the analyses show negative net present values. These results indicate that, to reach profitability, juvenile lobster production costs must be reduced 50% and the release strategy simultaneously optimized to increase the recapture rate to approximately 15%.
Monteilh-Zoller, M. K., Zonno, V., Storelli, C., and Ahearn, G. A. (1999). Effects of zinc on L-[H-3]proline uptake by lobster (Homarus americanus) hepatopancreatic brush-border membrane vesicles. Journal of Experimental Biology 202, 3003-3010.
Epithelial brush-border membrane vesicles (BBMVs),from the hepatopancreas of the lobster Homarus were prepared using a magnesium precipitation technique and employed in transport experiments designed to demonstrate the effects of external and internal divalent cationic heavy metals on the uptake of L-[H- 3]proline. When BBMVs were exposed to a high external concentration (2.5 mmol l(-1)) of Cd2+, Cu2+, Fe2+, Mn2+ or Zn2+, L-[H-3]proline (0.5 mmol l(-1)) uptake was significantly (P<0.05) decreased by each metal. However, if a 30 min pre- incubation period with each metal was used before incubation of the vesicles with amino acid and metal, a significant (P < 0.05) enhancement of L-[H-3]proline transport occurred. Zinc was the most stimulatory metal of those tested. Proline influxes (1.0 and 2.5 mmol l(-1)) were hyperbolic functions of bilateral [Zn2+], with a lower apparent zinc half-saturation constant (K-m) at the higher amino acid concentration. L-[H- 3]proline influx was a hyperbolic function of external I[L- proline] (K-m=2.10+/-0.26 mmol l(-1); J(max)=2290+/-600 pmol mg(-1) protein s(-1)) (means +/- S.E.M., N=3), and bilateral exposure to zinc significantly (P<0.05) increased the maximal rate of influx, J(max), of proline (J(max)=4890+/-250 pmol mg(- 1) protein 10 s(-1)), but had no effect (P>0.05) on apparent L- [H-3]proline binding to the membranes (K-m=1.66+/-0.23 mmol l(- 1)) (means +/- S.E.M., N=3), In the presence of 0.5 mmol l(-1) 1-pipecolate, bilateral zinc-stimulated, carrier-mediated, L- [H-3]proline influx was abolished. At low external concentrations of zinc alone (e.g. below 1.0 mmol l(-1)), L-[H- 3]proline influx was enhanced by the metal. Enhanced amino acid uptake in the presence of external zinc alone was abolished by L-pipecolate, A model accounting for external and internal zinc enhancements of L-[H-3]proline influx by the Na+-dependent L- pipecolate-sensitive IMINO transport system in these membranes is proposed.
Mori, K., and Stewart, J. E. (1978). Natural and induced bactericidal activities of the hepatopancreas of the American lobster, Homarus americanus. J Invertebr Pathol 32, 171-6.
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Moriyasu, M., Landsburg, W., Wade, E., and Maynard, D. R. (1999). The role of an estuary environment for regeneration of claws in the American lobster, Homarus americanus H.Milne Edwards, 1837 (Decapoda). Crustaceana 72, 415-433.
The life history of the American lobster, Homarus americanus, has been studied in the Bideford River estuary, Malpeque Bay, on the northern shore of Prince Edward Island, Canada. Lobsters migrate into the bay in early summer and two distinct moultings take place in May-June and in September. Lobsters with missing claws moult in both seasons, while uninjured individuals mainly moult in May-June. Neither uninjured lobsters nor individuals with missing claws larger than 43 mm CL moult twice a year in the estuary. A high percentage (30-40%) of individuals has missing claws in summer and the percentage of animals with regenerated small claws increases towards October-November After the regeneration of missing claws, lobsters appear to emigrate to deeper water outside the bay. The estuarine environment might be used as a moulting and regenerating area for injured animals in spring-fall. Conversely, this environment does not appear to sustain high reproductive activities, because a low prevalence of mature females is observed throughout the year in this environment. These findings reveal the diversity of habitats used by different stages and groups of lobsters, especially the importance of an estuarine environment for moulting of claw regenerating lobsters.
Morris, S., and Airriess, C. N. (1998). Integration of physiological responses of crustaceans to environmental challenge. South African Journal of Zoology 33, 87-106.
Brachyuran crustaceans are useful models for physiological studies because of their intermediate size and since they occupy a spectrum of habitats requiring widely varied behaviour. In this paper we examine the physiological responses to environmental fluctuations, extremes of habitat and consequent behaviours, with special emphasis on the adoption of air-breathing. It is established that metabolic end products such as lactate, intermediates including urate, and monoamine and peptide neurohormones can have important regulatory roles. These include effects on ventilation and heart function, blood perfusion, respiratory gas transport, as well as water and salt homeostasis providing an integrated suite of control mechanisms to regulate responses to environmental or behaviourally induced stress. A separate body of work has long suggested that the regulation of energy metabolism and provision of metabolic fuel for glycolysis is influenced by similar effecters. Most recently, metabolic end-products have been implicated as effecters of behaviour and thereby metabolic state. Thus, there is strong, emerging evidence for integration of physiological control mechanisms at the organismal level. We present new information, both mechanistic and from eco-physiological laboratory simulations, and from field studies of terrestrial crabs, that strengthens and extends the scope of this integration. Branchial chamber ventilation, cardiovascular function, relative perfusion of gills v. lungs, gas transport in the blood, the mobilisation of energy reserves, ion transport and water balance are all apparently influenced by similar messengers which coordinate and optimise these functions to meet specific requirements.
Morris, S., and Callaghan, J. (1998). The emersion response of the Australian Yabby Cherax destructor to environmental hypoxia and the respiratory and metabolic responses to consequent air-breathing. Journal of Comparative Physiology B-Biochemical Systemic and Environmental Physiology 168, 389-398.
The Australian Yabby Cherax destructor voluntarily emerges from water to breathe air with increased frequency as water PO2 decreases. When the water PO2 declined below 2.7 kPa the crayfish spent >50% of time breathing air. The respiratory gas transport, acid-base, ionic and energetic status were quantified in simulations of this emersion behaviour to determine the benefits that the crayfish may gain from switching to air-breathing. C. destructor initially showed an elevated O-2 uptake rate on emerging from hypoxic water, but after 1 h the O-2 uptake rate was not different from that of crayfish in normoxic water. During 3 h of air breathing, subsequent to 2.7 kPa aquatic hypoxia, the haemolymph PO2 increased while oxygen content was essentially unchanged, although cardiac output increased 5-fold. The haemolymph PCO2 increased from 0.44 to 1.21 kPa after 3 h while the CO2 content increased from 3.47 to 8.66 mmol.l(-1) and the pH decreased from 7.73 to 7.57 after 1 h in air. In air C.destructor eventually achieved an O-2 uptake rate similar to that achieved in water. A general hyperglycaemia occurred without anaerobiosis. In air-breathing C. destructor, small changes in lactate appear to offset the decrease in haemocyanin-O-2 affinity caused by acid Bohr shift. During air-breathing, decreased haemocyanin-O-2 affinity assisted in maintaining O-2 diffusion into the tissues, but the ATP content of the tail muscle decreased so that after 3 h in air the energy charge was only 0.59. The data are consistent with a specific depression of the Emden-Meyerhof pathway, preventing either lactate formation or oxidative phosphorylation in the tail muscle, despite a concomitant glycogenolysis.
Morris, S., and Oliver, S. (1999). Circulatory, respiratory and metabolic response to emersion and low temperature of Jasus edwardsii: simulation studies of commercial shipping methods. Comparative Biochemistry and Physiology a-Molecular and Integrative Physiology 122, 299-308.
The Southern Rock Lobster Jasus edwardsii is a commercial species. The respiratory and metabolic response of J. edwardsii during simulated commercial handling was investigated. Lobsters were dipped in 5 degrees C seawater for 2 min and exposed to air for up to 30 h in shipping cases containing ice (chilled), or packed without chilling. Controls were immersed at 18 degrees C. Chilling ameliorated tachycardia and hyperventilation caused by the packing process. Non-chilled J. edwardsii accumulate an O-2 deficit but chilling lobsters delayed anaerobiosis for up to a day. Haemolymph urate accumulated only in non-chilled lobsters, indicative of a rapid tissue hypoxia. The muscle ATP concentration of J. edwardsii in air decreased, regardless of chilling, with a corresponding loss of energy charge. A hyperglycaemia in emersed J. edwardsii was accompanied by decreased glycogen stores in chilled lobsters. The low IMP concentration in chilled J. edwardsii shows that 30-h emersion stress probably does not compromise taste and value of the lobsters. Chilling extends shipping time and distance, so after 10 or 30 h in transit, the lobsters are largely aerobic. When the chilled lobsters reach their destination after 30 h, accumulated IMP and inosine, and decreased glycogen, may have a significant effect on taste. Recovery is important before cooking if a fresh flavour is desired. (C) 1999 Published by Elsevier Science Inc. All rights reserved.
Morris, S., and Oliver, S. (1999). Respiratory gas transport, haemocyanin function and acid-base balance in Jasus edwardsii during emersion and chilling: simulation studies of commercial shipping methods. Comparative Biochemistry and Physiology a-Molecular and Integrative Physiology 122, 309-321.
The Southern Rock Lobster Jasus edwardsii is a commercial species often shipped in air. Respiratory gas transport, haemocyanin function and acid-base balance were assessed during emersion and emersion with chilling; i.e. reduced packing and shipping temperature. The affinity of the haemocyanin (Hc) for O-2 was low (P-50 - 3.44 kPa, 20 degrees C) but was increased by urate and Ca but not L-lactate. Chilling from 25 to 5 degrees C increased Hc-O-2 affinity (Delta H = 36.6 kJ mol(-1) at pH 7.4) and reduced the Bohr shift from phi = - 0.2 to - 0.09. In air, non-chilled lobsters became acidotic while chilling induced an alkalosis. The haemolymph P-o2 of non- chilled J. edwardsii in air decreased and the a - v P-o2 difference declined, prompting immediate anaerobiosis. Chilling J. edwardsii lowered metabolism and maintained P-ao2 for up to 5 h in air. Thereafter, emersion depleted the venous O-2 reserve. In non-chilled lobsters a urate-induced increase in Hc-O-2 affinity appeared important but these lobsters were unable to maintain respiration adequately and were reliant on anaerobiosis. As the chilled lobsters warmed they were unable to load adequate O-2 and the venous reserve became depleted. Oxygen transport and respiration were assisted by increased haemolymph urate, and together with chilling enabled O-2 uptake and transport to meet demand for 30 h in air. (C) 1999 Elsevier Science Inc. All rights reserved.
Mortin, L. I., and Marder, E. (1991). Differential distribution of beta-pigment-dispersing hormone (beta-PDH)- like immunoreactivity in the stomatogastric nervous system of five species of decapod crustaceans. Cell Tissue Res 265, 19-33.
Pigment-dispersing hormone (PDH) acts to disperse pigments within the chromatophores of crustaceans. Using an antibody raised against beta- PDH from the fiddler crab Uca pugilator, we characterized the distribution of beta-PDH-like immunoreactivity in the stomatogastric nervous system of five decapod crustaceans: the crabs, Cancer borealis and Cancer antennarius, the lobsters, Panulirus interruptus and Homarus americanus, and the crayfish, Procambarus clarkii. No somata were stained in the stomatogastric ganglion (STG) or the esophageal ganglion in any of these species. Intense PDH-like staining was seen in the neuropil of the STG in P. interruptus only. In all 5 species, cell bodies, processes, and neuropil within the paired circumesophageal ganglia (CGs) showed PDH-like staining; the pattern of this staining was unique for each species. In each CG, the beta-PDH antibody stained: 1 large cell in C. borealis; 3 small to large cells in C. antennarius; 3-8 medium cells in P. clarkii; 1-4 small cells in H. americanus; and 13-17 small cells in P. interruptus. The smallest cell in each CG in C. antennarius sends its axon, via the inferior esophageal nerves, into the opposite CG; this pair of cells, not labeled in the other species studied, may act as bilateral coordinators of sensory or motor function. These diverse staining patterns imply some degree of evolutionary diversity among these crustaceans. A beta-PDH-like peptide may act as a neuromodulator of the rhythms produced by the stomatogastric nervous system of decapod crustaceans.
Moulins, M., and Cournil, I. (1982). All-or-none control of the bursting properties of the pacemaker neurons of the lobster pyloric pattern generator. J Neurobiol 13, 447-58.
In Crustacea the central pattern generator for the pyloric motor rhythm (filtration to the midgut) is known to be located within the stomatogastric ganglion (STG); its cycling activity is known to be organized by three endogenous burster neurons acting as pacemakers and driving 11 follower neurons. In Homarus, recordings from the isolated stomatogastric nervous system (Fig. 1) indicate that (1) the pyloric output can be generated only when the STG is afferented (i.e., connected to the more rostral oesophageal and commissural ganglia) (Fig. 2) and (2) the deafferentation of the STG results in a complete loss of the bursting properties of the pacemaker neurons (Fig. 4). Manipulation of the STG inputs responsible for unmasking the properties of the pacemakers strongly suggests that (1) they are not phasic inputs (Fig. 5) and (2) they are long-term acting inputs (Fig. 6). These results provide evidence for a neural all-or-none control of the bursting properties of the pacemaker neurons of a motor pattern generator.
Moulins, M., and Nagy, F. (1982). Control of integration by extrinsic inputs in the crustacean pyloric circuit. J Physiol 78, 755-64.
The pyloric circuit (14 neurones) in the stomatogastric ganglion of crustacea (Jasus, Homarus) is the central pattern generator of the motor output which governs the rhythmic movements of the pyloric chamber (Fig. 1). Although the intrinsic burstiness of these neurones plays a crucial role in the generation of the rhythmic output, it is demonstrated here that expression of this burstiness is completely dependent on extrinsic inputs (Fig. 2). Tonic firing of an identified interneurons (APM) projecting to the pyloric circuit is able to induce bursting in pyloric neurones. It also modifies the characteristics of the regenerative changes in membrane potential which underly bursting of these neurones (Fig. 3). Tonic firing of APM strongly modifies the phase at which each pyloric neurone fires in the cycle (Fig. 4 and 5). This phage control also appears to be achieved through control of the bursting properties of the pyloric neurones. Rhythmic firing of an identified pyloric oscillator neurone (CP) in the commissural ganglia (Fig. 6) that projects to the circuit in the stomatogastric ganglion, is able to entrain the pyloric rhythm (Fig. 7). Each pyloric neurone can be entrained by CP with different coupling ratios (Fig. 8). This higher order oscillator appears to act as a frequency controller of the bursting of each pyloric neurone.
Mourente, G., and Rodriguez, A. (1997). Effects of salinity and dietary DHA (22:6n-3) content on lipid composition and performance of Penaeus kerathurus postlarvae. Marine Biology 128, 289-298.
A two-way ANOVA experiment was designed to study the effects of salinity and dietary docosahexaenoic acid (DHA; 22:6n-3) on lipid composition and performance of postlarvae from the marine shrimp Penaeus kerathurus (Forskal, 1775). Shrimp were reared from 1- to 8-d-old postlarvae at 35 and 25 parts per thousand S with Kelko-enriched Artemia sp. [20.0 mu g (n-3)HUFA mg(-1) dry weight; 9.1 mu g DHA mg-l dry weight] and nonenriched Artemia sp. [14.2 mu g (n-3) HUFA mg(-1) dry weight; 0.3 mu g DHA mg(- 1) dry weight]. Dietary DHA content did not affect either total length or survival but influenced the nutritional status represented by condition indices (triacylglycerol/total polar lipid and triacylglycerol/free cholesterol) of 8-d-old postlarvae at the end of the experiment. Culture salinity affected final total length and condition indices but did not show any effect on survival in the different experimental treatments. The interaction of dietary DHA and culture salinity was not significant for total length and survival but was significant for both condition indices used. P. kerathurus 8-d- old postlarvae showed better growth, survival and nutritional condition when reared at 35 parts per thousand S and when fed on Kelko-enriched Artemia sp., but the differences with postlarvae from other treatments were very poorly marked. The results demonstrate that 8-d-old postlarvae may have sufficiently developed osmoregulatory capabilities to resist 25 parts per thousand S under good conditions, although (n-3) HUFA-enriched diets may also enhance osmotic stress resistance, general performance and disease resistance.
Mulloney, B., and Hall, W. M. (1991). Neurons with histaminelike immunoreactivity in the segmental and stomatogastric nervous systems of the crayfish Pacifastacus leniusculus and the lobster Homarus americanus. Cell Tissue Res 266, 197-207.
We used a polyclonal antiserum against histamine to map histaminelike immunoreactivity (HLI) in whole mounts of the segmental ganglia and stomatogastric ganglion of crayfish and lobster. Carbodiimide fixation permitted both HRP-conjugated and FITC-conjugated secondary antibodies to be used effectively to visualize HLI in these whole mounts. Two interneurons that send axons through the inferior ventricular nerve (ivn) and the stomatogastric nerve to the stomatogastric ganglion had strong HLI, both in crayfish and in lobster. These ivn interneurons were known from other evidence to be histaminergic. The neuropil of the stomatogastric ganglion in both crayfish and lobster contained brightly labeled terminals of axons that entered the ganglion from the stomatogastric nerve. No neuronal cell bodies in this ganglion had HLI. Each segmental ganglion contained at least one pair of neurons with HLI. Some neurons in the subesophageal ganglion and in each thoracic ganglion labeled very brightly. Axons of projection interneurons with strong HLI occurred in the dorsal lateral tracts of each segmental ganglion, and sent branches to the lateral neurophils and tract neurophils of each ganglion. All the labeled neurons were interneurons; no HLI was observed in peripheral nerves.
Murali, N., Jarori, G. K., and Rao, B. D. (1994). Two-dimensional transferred nuclear Overhauser effect spectroscopy (TRNOESY) studies of nucleotide conformations in arginine kinase complexes. Biochemistry 33, 14227-36.
Two-dimensional proton transfer nuclear Overhauser spectroscopy (TRNOESY) studies of the conformations of the adenosine moieties in the nucleotides bound at the active site of the lobster (Homarus americanus) muscle arginine kinase are reported. TRNOESY measurements were made using a sample protocol chosen to minimize contributions from weak non-specific binding of the nucleotides to the observed NOE's. This was done by making the measurements as a function of ligand concentration while keeping the ligand to enzyme concentration ratio fixed at 10:1. The experiments were performed at 500 MHz and 10 degrees C for six different mixing times in the range 40-300 ms. The measurements were made on three complexes of the enzyme: E.MgATP, E.MgADP, and the long-lived transition-state-analog complex (E.MgADP.NO- 3.arginine). All the complexes, including the transition-state-analog complex with an estimated lifetime of about 50 ms, satisfy the fast- exchange condition. The TRNOE buildup curves for all the nucleotide- proton pairs in each complex were analyzed using a complete relaxation matrix appropriate for fast exchange. The interproton distances obtained from the NOE analysis were used as constraints in obtaining an energy-minimized conformation on the basis of the program CHARMm. The glycosidic torsion angle (chi) for the adenosine moiety in all three complexes is about 50 degrees +/- 5 degrees. The glycosidic orientation agrees well with that determined for MgATP and MgADP complexes of creatine kinase (Murali et al., 1993), MgATP bound at the active and ancillary sites of pyruvate kinase (Jarori et al., 1994a), and PRPP synthetase (Jarori et al., 1994b).(ABSTRACT TRUNCATED AT 250 WORDS).
Murison, D. J., Moore, D. C., McHenery, J. G., Robertson, N. A., and Davies, I. M. (1997). Epiphytic invertebrate assemblages and dichlorvos usage at salmon farms. Aquaculture 159, 53-66.
Dichlorvos (DDVP) is an organophosphate medicine, used to treat farmed salmon infested with ectoparasitic crustacean sea lice. Field evidence was sought for effects of DDVP usage on mid-tide level invertebrate assemblages associated with the macrophyte Ascophyllum nodosum on shores adjacent to salmonid cages. There was no evidence of impoverishment in Ascophyllum communities in general, and non-target crustacean, populations in particular, that could be related to de-lousing operations, Acetylcholinesterase activity in Hyale nilssoni was progressively inhibited with increasing DDVP concentrations. There were indications of reduced AChE activity in Hyale and Carcinus maenas and greater resistance to DDVP in animals collected close to the fish farm with greater usage of DDVP. Crown Copyright (C) 1997 Published by Elsevier Science Ltd.
Musial, C. J., and Uthe, J. F. (1986). Rapid, semimicro method for determination of polycyclic aromatic hydrocarbons in shellfish by automated gel permeation/liquid chromatography. J Assoc Off Anal Chem 69, 462-6.
A simple, rapid, easily automated method is described for the determination of polycyclic aromatic hydrocarbons (PAHs) in shellfish such as American lobster (Homarus americanus) and blue mussel (Mytilus edulis). PAHs are extracted from small amounts (1-8 g) of tissue by saponification in 1N ethanolic potassium hydroxide followed by partitioning into 2,2,4-trimethylpentane. This solution is evaporated just to dryness by rotary evaporation and the residue is dissolved in cyclohexane-dichloromethane (1 + 1) for gel permeation chromatography (GPC) on Bio-Beads SX-3. The GPC procedure is ideal as a screening method in the range 25-18 000 ng PAHs/g tissue. If individual PAH measurements are required, the appropriate GPC fraction is collected and PAHs are separated by reverse phase liquid chromatography (LC) with fluorometric detection. Individual PAHs at concentrations as low as 0.25-10 ng/g can be determined. Recoveries of added fluoranthene, pyrene, benz[a]anthracene, chrysene, benzo[e]pyrene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, dibenz[a,h]anthracene, benzo[ghi]perylene, and indeno[1,2,3-cd]pyrene were quantitative, with relative standard deviations ranging from 0.0 to 16.9%.
Mykles, D. L. (1985). Heterogeneity of myofibrillar proteins in lobster fast and slow muscles: variants of troponin, paramyosin, and myosin light chains comprise four distinct protein assemblages. J Exp Zool 234, 23-32.
Fast and slow muscles from the claws and abdomen of the American lobster Homarus americanus were examined for adenosine triphosphatase (ATPase) activity and for differences in myofibrillar proteins. Both myosin and actomyosin ATPase were correlated with fiber composition and contractile speed. Four distinct patterns of myofibrillar proteins observed in sodium dodecyl sulfate-polyacrylamide gels were distinguished by different assemblages of regulatory and contractile protein variants. A total of three species of troponin-T, five species of troponin-I, and three species of troponin-C were observed. Lobster myosins contained two groups of light chains (LC), termed "alpha" and "beta." There were three alpha-LC variants and two beta-LC variants. There were no apparent differences in myosin heavy chain, actin, and tropomyosin. Only paramyosin showed a pattern completely consistent with muscle fiber type: slow fibers contained a species (105 kD) slightly smaller than the principle variant (110 kD) in fast fibers. It is proposed that the type of paramyosin present could provide a biochemical marker to identify the fiber composition of muscles that have not been fully characterized. The diversity of troponin and myosin LC variants suggests that subtle differences in physiological performance exist within the broader categories of fast- and slow- twitch muscles.
Mykles, D. L. (1988). Histochemical and biochemical characterization of two slow fiber types in decapod crustacean muscles. J Exp Zool 245, 232-43.
Myofibrillar proteins in muscles of the claws and abdomen of lobster, Homarus americanus, and the claws of fiddler crab, Uca pugnax, and land crab, Gecarcinus lateralis, have been analyzed with sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Fibers contained numerous isoforms of structural and regulatory proteins in assemblages correlated with fiber type. One fast (F) and two slow (S1 and S2) fibers were identified. All F fibers possessed two isoforms of paramyosin (P1 and P2), while all slow fibers, with the exception of Uca major claw, contained only the P2 variant. S1 and S2 fibers were distinguished by the distribution of a large isoform of troponin-T (T1; Mr = 55,000); S2 fibers in all three species contained T1 in addition to one or two smaller-molecular-weight variants usually associated with S1 fibers. In order to determine whether the slow fibers differed in histochemical properties, land crab claw closer muscle was cryosectioned and stained for myofibrillar ATPase and NADH diaphorase activities. Most S2 fibers had lower ATPase and higher NADH diaphorase activities than S1 fibers, which indicated that S2 fibers had a lower rate of contraction and were more fatigue-resistant than S1 fibers. It is proposed that the S1 and S2 fibers defined by biochemical and histochemical criteria are identical to the slow-twitch and tonic fibers, respectively characterized physiologically.
Mykles, D. L. (1997). Crustacean muscle plasticity: Molecular mechanisms determining mass and contractile properties. Comparative Biochemistry and Physiology B-Biochemistry & Molecular Biology 117, 367-378.
Two crustacean models for understanding molecular mechanisms of muscle plasticity are re viewed. Metabolic changes underlying muscle protein synthesis and degradation have been examined in the Bermuda land crab, Gecarcinus lateralis. During proecdysis, the claw closer muscle undergoes a programmed atrophy, which results from a highly controlled breakdown of myofibrillar proteins by Ca2+-dependent and, possibly, ATP/ubiquitin- dependent proteolytic enzymes. The advantage of this model is that there is neither fiber degeneration nor contractile-type switching, which often occurs in mammalian skeletal muscles. The second model uses American lobster, Homarus americanus, to understand the genetic regulation of fiber type switching. Fibers in the claw closer muscles undergo a developmentally regulated transformation as the isomorphic claws of larvae and juveniles differentiate into the heteromorphic cutter and crusher claws of adults. This switching occurs at the boundary between fast- and slow-fiber regions, and thus the transformation of a specific fiber is determined by its position within the muscle. The ability to predict fiber switching can he exploited to isolate and identify putative master regulatory factors that initiate and coordinate the expression of contractile proteins. (C) 1997 Elsevier Science Inc.
Mykles, D. L., Cotton, J. L. S., Taniguchi, H., Sano, K. I., and Maeda, Y. (1998). Cloning of tropomyosins from lobster (Homarus americanus) striated muscles: fast and slow isoforms may be generated from the same transcript. Journal of Muscle Research and Cell Motility 19, 105-115.
Complementary DNAs encoding fibre-type-specific isoforms of tropomyosin (Tm) have been isolated from lobster (Homarus americanus) striated muscle expression libraries made from poly(A)(+) RNA purified from deep abdominal (fast-type) and crusher-claw closer (slow-type) muscles. A cDNA of slow-muscle Tm (sTm(1)), containing a complete open reading frame (ORF) and portions of the 5' and 3' untranslated regions (UTRs), encodes a protein of 284 amino acid residues with a predicted mass of 32 950, assuming acetylation of the amino terminus. The nucleotide sequence of a fast-muscle tropomyosin (fTm cDNA), which includes the entire ORF and part of the 3' UTR, is identical to that of sTm(1) cDNA, except in the region encoding amino acid residues 39-80 (equivalent to exon 2 of mammalian and Drosophila muscle tropomyosin genes). The deduced amino acid sequences, which display the heptameric repeats of nonpolar and charged amino acids characteristic of alpha- helical coiled-coils, are highly homologous to tropomyosins from rabbit, Drosophila, and shrimp (57% to 99% identities, depending on species). Northern blot analysis showed that two transcripts (1.1 and 2.1 kb) are present in both fibre types. Mass spectrometry indicated that fast muscle contains one major isoform (fTm: 32 903), while slow muscle contains two major isoforms (sTm(1) and sTm(2): 32 950 and 32 884 respectively). Both Tm preparations contained minor species with a mass of about 32 830. Sequences of peptides derived from purified slow and fast Tms were identical to the deduced amino acid sequences of the sTm(1) and fTm cDNAs, respectively, except in the C- terminal region of fTm. The difference in mass between that predicted by the deduced sequence (32 880) and that measured by mass spectrometry (32 903) suggests that fTm is posttranslationally modified, in addition to acetylation of the N-terminal methionine. These data are consistent with the hypothesis that the fTm and sTm(1) are generated by alternative splicing of two mutually-exclusive exons near the 5' end of the same gene. (C) Chapman & Hall Ltd.
Mykles, D. L. (1999). Proteolytic processes underlying molt-induced claw muscle atrophy in decapod crustaceans. American Zoologist 39, 541-551.
The claw muscles of large-clawed decapod crustaceans undergo a programmed atrophy in preparation for molting, or ecdysis. This is mediated by five cytosolic proteinases organized into two proteolytic pathways: calcium-dependent and ubiquitin/proteasome-dependent. The calcium-dependent system consists of four calcium-dependent cysteine proteinases (CDPs I, IIa, IIb, and III; native masses 310, 125, 195, and 59 kDa, respectively) that completely degrade myofibrillar proteins and are activated in atrophic muscles. Immunological analysis shows that the active-site sequence in CDP IIa (60-kDa subunit mass) is similar to that in mammalian CDPs (calpains), and that CDP IIb is homologous to a calpain-like gene isolated from Drosophila cDNA Libraries. Increased intracellullar Ca2+ stimulates proteolysis in situ, indicating CDPs play an important role in muscle protein catabolism. The ubiquitin/proteasome-dependent system involves the ATP- dependent conjugation of multi-ubiquitin chains to protein by ubiquitin-conjugating enzymes. This acts as a signal for substrate degradation by the 26S proteasome, a multi-subunit complex consisting of a 20S proteasome catalytic "core" and two PA700 (19S) regulatory complexes. Polyubiquitin mRNA, ubiquitin-protein conjugates, and 20S proteasome are elevated about 5-, 8-, and 2-fold, respectively, during atrophy. A heat- induced form of the 20S proteasome hydrolyzes myosin, troponin, and tropomyosin to large fragments in vitro. Biochemical studies identified the branched-chain amino acid-preferring (BrAAP) activity, one of six distinct catalytic components in the complex, as the activity that carries out these initial cleavages. These results indicate that the ubiquitin/proteasome pathway is involved, but its precise role remains to be resolved.
Nadol, J. B., Jr., and De Lorenzo, A. J. (1968). Observations on the abdominal stretch receptor and the fine structure of associated axo-dendritic synapses and neuromuscular junctions in homarus. J Comp Neurol 132, 419-43.
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Nadol, J. B., Jr., and Darin de Lorenzo, A. J. (1969). Observations on the organization of the dendritic processes and receptor terminations in the abdominal muscle receptor organ of Homarus. J Comp Neurol 137, 19-31.
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Nadol, J. B., Jr., Brzin, M., and De Lorenzo, A. J. (1970). Fine structural localization of acetylcholinesterase in sensory and motor neurons of the muscle receptor organ in homarus. J Comp Neurol 140, 399-419.
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Nagy, F., and Cardi, P. (1994). A rhythmic modulatory gating system in the stomatogastric nervous system of Homarus gammarus. II. Modulatory control of the pyloric CPG. J Neurophysiol 71, 2490-502.
1. In the European rock lobster, Homarus gammarus, two bilaterally symmetrical pairs of commissural neurons, P and commissural pyloric (CP), evoke excitatory postsynaptic potentials in the neurons of the pyloric motor network. The present paper shows that the two commissural neurons also exert a modulatory control over the pyloric network. 2. The P and CP neurons were active during ongoing pyloric rhythms. Ongoing pyloric activity was terminated when the neurons were hyperpolarized to inhibit their firing. 3. When the pyloric network was quiescent, depolarizing either the P or CP neuron induced a robust pyloric rhythm. 4. We studied the actions of the P and CP neurons on individual pyloric neurons isolated in situ from network interactions by a photoinactivation techniques. The P neuron induced oscillatory properties in the pacemaker pyloric dilator (PD) neurons and the motor neuron, ventricular dilator (VD), whereas the CP neuron induced rhythmogenic properties in all the network neurons but VD. Together, the P-CP neurons modulated the entire pyloric network. The modulatory effects of the P-CP neurons did not outlast the duration of their discharge. 5. The P and CP neurons also controlled the firing frequency of all the pyloric neurons. They may, in addition, control phasing of the constrictor neurons discharges, but this effect was state-dependent and occurred only when the pyloric central pattern generator was functioning weakly. Their role in providing flexibility to the network operation appeared relatively limited. 6. We conclude that the P and CP neurons are good candidates for insuring long-term maintenance of pyloric network activity patterns.
Nagy, F., Cardi, P., and Cournil, I. (1994). A rhythmic modulatory gating system in the stomatogastric nervous system of Homarus gammarus. I. Pyloric-related neurons in the commissural ganglia. J Neurophysiol 71, 2477-89.
1. Operation of the pyloric neural network in the crustacean stomatogastric ganglion (STG) depends on constant firing of modulatory inputs from anterior ganglia. We have identified two bilaterally symmetrical pairs of these inputs in the commissural ganglia (COGs) of the European rock lobster Homarus gammarus. During operation of the pyloric CPG, they fired in pyloric time, out of phase with the pyloric pacemakers. 2. One of the pair was the commissural pyloric (CP) neuron and the other was homologous to the P neuron described in the spiny lobster Panulirus interruptus. We describe their morphology and location in the COG. The CP neuron projected to the STG via the superior esophageal nerve (son) and the stomatogastric nerve (stn), whereas the P neuron projected via the inferior esophageal nerve (ion) and stn. 3. To determine the total number of commissural neurons projecting to the STG, we used cobalt and Lucifer yellow backfilling from their cut axons in the stn. With the ion cut, there were between 8 to 12 labeled somata in each COG including CP cell body, whereas only 2 somata (including P) were labeled with the son cut. Among these neurons, CP and P appeared to be the only commissural neurons that fired in pyloric time and projected in the STG on the pyloric network. 4. The CP neuron produced monosynaptic excitatory postsynaptic potentials (EPSPs) on the pyloric dilator (PD), lateral pyloric (LP), and inferior cardiac (IC) neurons, whereas the P neuron produced monosynaptic EPSPs on all pyloric motoneurons but IC. The P neuron was gamma-aminobutyric acid immunoreactive, and the P-derived EPSPs in pyloric neurons were reversibly blocked by bicuculline, picrotoxin, and D-tubocurarine. 5. The CP and P neurons were electrically coupled, and modification of membrane potential in either one of them appreciably changed the firing frequency of the coupled neuron. 6. A negative- feedback loop from the pyloric anterior burster (AB) interneuron provoked simultaneous rhythmic inhibitions in the P and CP neurons. Together with the electrical coupling, the rhythmic inhibition contributed to synchronize firing of the two commissural neurons. 7. The following papers in the series of describe the modulatory and rhythmic control exerted by the P and CP neurons over the pyloric pattern generator.
Nassel, D. R. (1999). Histamine in the brain of insects: A review. Microscopy Research and Technique 44, 121-136.
Histamine is the neurotransmitter of photoreceptors in insects and other arthropods. As a photoreceptor transmitter, histamine acts an ligand-gated chloride channels. Another type of histamine receptor has been indicated in the insect central nervous system by binding pharmacology. This receptor is similar to the mammalian H 1 receptors, which are G-protein coupled and thus utilize a second messenger system. The distribution of histamine-immunoreactive (HAIR) neurons has been studied in a few insect species: cockroaches, locust, crickets, honey bee, blowfiies, and in Drosophila. In addition to its presence in photoreceptor cells, histamine is distributed in a rather small number of neurons in the insect brain. Many of these neurons have extensive bilateral arborizations that innervate several distinct neuropil regions, notably in the protocerebrum Some patterns of histamine distribution are seen in all the species. On the other hand, the number and morphology of neurons differ between the studied species, and several major neuropils (central body, antennal lobes, mushroom bodies) are supplied by HAIR neurons in some species, but not in others. Thus it appears that there are some species-specific functions of histamine and on others that are preserved between species. Some of the histaminergic neurons may constitute wide field inhibitory systems with functions distinct from those of neurons containing gamma-amino butyric acid (GABA). Novel data are presented for Drosophila and the cockroach Leucophaea maderae and a comparison is made with published data on other insects. Microsc. Res. Tech. 44:121- 136, 1999. (C) 1999 Wiley-Liss, Inc.
Naylor, J. K., Taylor, E. W., and Bennett, D. B. (1999). Oxygen uptake of developing eggs of Cancer pagurus (Crustacea : Decapoda : Cancridae) and consequent behaviour of the ovigerous females. Journal of the Marine Biological Association of the United Kingdom 79, 305-315.
This study investigated factors affecting the metabolic rate of Cancer pagurus eggs. The oxygen uptake of portions of the egg mass and recently hatched zoeae was measured. Oxygen uptake of the eggs of an individual animal was found to vary widely, with measured mean values under normoxic conditions ranging from 38 to 250 mu moles O-2 kg(-1) min(-1) Mean values for the oxygen uptake of zoeae ranged from 958 to 1168 mu moles O-2 kg(- 1)min(-1) Mean rates of oxygen uptake of the eggs generally increased with increasing seasonal temperature and advancing developmental stage. Rates of oxygen uptake were maintained over a wide range of ambient oxygen partial pressures. As oxygen partial pressure in the seawater surrounding the eggs fell from a critical value (P-c) of between 60 and 90 mm Hg, the oxygen uptake of the eggs also declined. Mean values for ambient oxygen partial pressures within the egg mass in vivo ranged from 34 to 98 mm Hg. Adult female C. pagurus appear to be able to detect conditions within the egg mass and adjust their egg ventilation behaviour accordingly. Active egg mass ventilation by the adult increased as the eggs became more developed and their oxygen demands increased.
Neil, D. M., Macmillan, D. L., Robertson, R. M., and Laverack, M. S. (1976). The structure and function of thoracic exopodites in the larvae of the lobster Homarus gammarus (L.). Philos Trans R Soc Lond B Biol Sci 274, 53-68.
The first three larval stages of the lobster Homarus gammarus are pelagic swimming animals. A description is given of the exopodite apparatus of the thoracic appendages that provide lift and propulsive power in these stages. Setal arrangement and display provides greater surface area during power strokes. Musculature is peculiar to the exopodites and concerned with rotational movements of the appendage. Metachronal beating takes place with the segmental appendages moving in a variable sequence.
Newkirk, R. F., Ballou, E. W., Vickers, G., and Whittaker, V. P. (1976). Comparative studies in synaptosome formation: preparation of synaptosomes from the ventral nerve cord of the lobster (Homarus americanus). Brain Res 101, 103-11.
A flotation method for preparing synaptosomes, previously developed for work with squid nervous tissue, has now been successfully applied to the ventral nerve cord of lobster. Perhaps due to the greater content of connective tissue, homogenization of the lobster nerve cord was more difficult than with squid optic lobes and the yield of synaptosomes was lower. The synaptosomes fraction showed a 3.8-fold enrichment of bound acetylcholine relative to the homogenate and was almost 10 times richer in acetylcholine than a guinea pig cerebral cortical synaptosome fraction. The lobster synaptosomes accumulated choline rapidly when incubated at room temperature in sea water, and showed a high degree of occlusion of lactate dehydrogenase, thus confirming that they are sealed structures. The lobster can thus be added to the wide range of species from whose nervous systems synaptosomes can be isolated, and merits further study as a possibly rich source of cholinergic synaptosomes.
Nickell, L. A., and Sayer, M. D. J. (1998). Occurrence and activity of mobile macrofauna on a sublittoral reef: Diel and seasonal variation. Journal of the Marine Biological Association of the United Kingdom 78, 1061-1082.
Underwater television observations were made of mobile macrofauna inhabiting two parts of a sublittoral reef on the west coast of Scotland for 48h periods in spring, summer, autumn and winter. Continuous occurrence profiles (mean hourly frequency of occurrence, %) were detailed for 12 species of fish (Chirolophis ascanii, Conger conger, Ctenolabrus rupestris, Lepadogaster candollei, Myoxocephalus scorpius, Pholis gunnellus, Pollachius pollachius, Raniceps raninus, Phrynorhombus regius, Zeugopterus punctatus, Thorogobius ephippiatus and Trisopterus minutus), ten crustacean species (Cancer pagurus, Carcinus maenas, Galathea strigosa, Homarus gammarus, Inachus spp., Munida rugosa, Necora puber, Brachyuran sp., Caridean sp. and Pagurid sp.) and four echinoderm species (Antedon bifida, Asterias rubens, Henricia oculata and Solaster endeca). Rhythmic patterns of diel activity and/or occurrence were identified for several species. Chirolophis ascanii, Ctenolabrus rupestris, L. candollei, Myoxocephalus scorpius, Pholis gunnellus, Pollachius pollachius, Thorogobius ephippiatus, Trisopterus minutus and Munida rugosa were predominantly diurnal, but Ctenolabrus rupestris, Myoxocephalus scorpius and Trisopterus minutus also showed some evidence of crepuscular activity. Raniceps raninus activity was predominantly nocturnal but became continuous in summer. In other species (the topknots Phrynorhombus regius and Z. punctatus and the crustaceans Cancer pagurus and Homarus gammarus) identifiable occurrence patterns changed with season or site. The greatest number of fish species occurred in winter with Myoxocephalus scorpius, Pollachius pollachius and topknots (Phrynorhombus regius and Z. punctatus) showing greater occurrence/activity during spring and winter. Go-occurrence analysis was used to identify species interactions or avoidances.
Nies, A. T., Kinne, R. K., Kinne-Saffran, E., and Grieshaber, M. K. (1995). Urate transport in Homarus americanus hepatopancreas: studies on membrane vesicles and R cells. Am J Physiol 269, R339-49.
[2-14C]urate uptake was studied in hepatopancreatic basolateral membrane vesicles and in R cell suspensions of the American lobster by Millipore filtration techniques. Unspecific binding of urate to the vesicular membrane was 25.5 +/- 3.0% of equilibrium. Vesicular uptake showed a diffusional and a saturable component (Km) 0.37 +/- 0.04 mM and maximal velocity (Vmax) 16.5 +/- 1.2 pmol urate.mg protein-1.s-1). [2-14C]urate uptake was significantly trans-stimulated by urate. Purine analogues, probenecid, p-aminohippuric acid, pyrazinoic, and oxonic acid cis-inhibited urate transport. Urate uptake was not affected by Na+ or K+ transmembrane gradients but stimulated by 1 mM 2-oxoglutarate at the cis-side in Na(+)-containing media. Cellular urate uptake was inhibited by pyrazinoic acid. Uptake was saturable (Km 0.53 +/- 0.11 mM and Vmax 3.7 +/- 0.4 pmol urate.mg protein-1.s-1) and Na(+)- independent. However, 2-oxoglutarate stimulated uptake in Na(+)- containing media. These results suggest that urate uptake across the basolateral membrane occurs via a specific, Na(+)-independent transport system that may operate in the exchange mode accepting 2-oxoglutarate as countertransported substrate. In vivo, urate uptake thereby would be a tertiary active system driven by a 2-oxoglutarate gradient established across the cell membrane by the operation of a Na(+)-2- oxoglutarate cotransport system.
Nilson, E. H., Fisher, W. S., and Shleser, R. A. (1976). A new mycosis of larval lobster (Homarus americanus). J Invertebr Pathol 27, 177-83.
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Nishita, K., and Ojima, T. (1990). American lobster troponin. J Biochem (Tokyo) 108, 677-83.
Troponin was isolated from the abdominal muscle of the American lobster (Homarus americanus) by essentially the same method as used for akazara scallop troponin [J. Biol. Chem. 261, 16749-16754 (1986)]. The thus isolated troponin together with lobster tropomyosin confers high Ca2(+)- sensitivity to rabbit reconstituted actomyosin. The troponin consists of components having Mr of about 42,000, 32,000, 30,000, and 17,000, but not the Mr 52,000-59,000 component previously reported to be present in several crustacean troponins. These troponin components were separated from each other by DEAE-Toyopearl column chromatography in the presence of 6 M urea. The Mr 17,000 component was further separated into one major and two minor components by the same chromatography, but each of them was confirmed to be a Ca2+ binding component, TnC. The Mr 32,000 and 30,000 components were both regarded as inhibitory subunits, TnIs, since the Mg-ATPase activity of actomyosin in the presence of tropomyosin was strongly inhibited by the addition of the components, and the inhibition was reversed by the further addition of TnC. Finally, the Mr 42,000 component was regarded as TnT, since this component formed stoichiometic complex with TnC and TnI, and was indispensable for Ca2+ regulation of the actomyosin-tropomyosin system.
Nousiainen, M., Rafn, K., Skou, L., Roepstorff, P., and Andersen, S. O. (1998). Characterization of exoskeletal proteins from the American lobster, Homarus americanus. Comparative Biochemistry and Physiology B-Biochemistry & Molecular Biology 119, 189-199.
Proteins from the calcified exoskeleton of the lobster, Homarus americanus, were extracted and separated by two-dimensional gel electrophoresis. Electroblotting the proteins onto polyvinylidene difluoride (PVDF) membranes followed by sequence determination gave 16 N-terminal amino acid sequences and revealed that further eight proteins were N-terminally blocked. The relative molecular mass, M-r, was obtained for most of the electrophoretically separated proteins by means of matrix- assisted laser desorption mass spectrometry (MALDIMS) after electroelution from Coomassie-stained two-dimensional polyacrylamide gels. Eleven proteins were purified from extracts of the exoskeleton by low pressure ion exchange chromatography and reversed-phase high performance chromatography, and their sequences were determined by combined use of Edman degradation and mass spectrometry. Good agreement was obtained between the M-r-values measured by mass spectrometry and those calculated from the sequences. Five of the sequenced proteins contain two copies of a previously observed 18-residue sequence motif, while a couple of the remaining sequences show similarity to sequences of exoskeletal proteins from shrimps and spiders. Only limited similarity to insect cuticular proteins was observed. (C) 1998 Elsevier Science Inc.
Ocorr, K. A., and Berlind, A. (1983). The identification and localization of a catecholamine in the motor neurons of the lobster cardiac ganglion. J Neurobiol 14, 51-9.
The cardiac ganglion from Homarus americanus was investigated for the purpose of providing biochemical and histochemical information as to the identity of the neurotransmitter(s) utilized by this system. Three techniques were employed in this study: (1) the glyoxylic acid histofluorescence staining technique (GA), which showed fluorescence characteristic of catecholamines localized in the five motor neurons; (2) high-voltage electrophoresis (HVE) in one dimension followed by ascending chromatography in the second dimension, which indicated incorporation of label from tritiated tyrosine into norepinephrine (NE) and small amounts of dopamine (DA); (3) high-pressure liquid chromatography with electrochemical detection (HPLC/EC), which indicated the presence of endogenous norepinephrine.
Offutt, G. C. (1970). Acoustic stimulus perception by the american lobster Homarus americanus (Decapoda). Experientia 26, 1276-8.
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Oh, C. W., Hartnoll, R. G., and Nash, R. D. M. (1999). Population dynamics of the common shrimp, Crangon crangon (L.), in Port Erin Bay, Isle of Man, Irish Sea. Ices Journal of Marine Science 56, 718-733.
The population structure, growth, mortality, and size at sexual maturity of the common shrimp (Crangon crangon) were examined in Port Erin Bay, Isle of Man, Irish Sea between April 1995 and July 1998. For estimation of parameters of growth and mortality, monthly length-frequency data were analysed by ELEFAN. The population consisted mostly of the first year class, with a similar size composition each year. Regressions of body wet weight on carapace length indicated isometric growth (exponents very close to 3.0). Parameters of growth were estimated, using the modified von Bertalanffy growth function (VBGF) model incorporating seasonal variation in growth. Females grew faster and reached a larger size at age than males (K=1.09 yr(-1) and L-infinity=18.5 mm CL for females, and K = 0.90 yr(-1) and L-infinity = 15.1 mm CL for males). The maximum life span is estimated as 3.3 years. The recruitment pattern shows one major recruitment event per year. Total mortality (Z) by length-converted catch curve was estimated at 3.96 yr(-1), fishing mortality (F) 0.36 yr(-1), and natural mortality (M) 3.60 yr(-1). The size at 50% sexual maturity for females ranged from 12.0 to 12.6 mm CL. Fecundity per recruit was 6.2 x 10(5). The exploitation rate (E) corresponding to 50% of the unexploited stock was 0.28 at L-25, 0.32 at L-50, and 0.35 at L-75. (C) 1999 International Council for the Exploration of the Sea.
Ohira, T., Watanabe, T., Nagasawa, H., and Aida, K. (1997). Molecular cloning of a molt-inhibiting hormone cDNA from the kuruma prawn Penaeus japonicus. Zoological Science 14, 785-789.
The crustacean molt-inhibiting hormone (MIH) is released from the X-organ sinus gland complex and suppresses ecdysteroid synthesis by the Y-organ. In the present study, we have isolated a cDNA which encodes a MIH (Pej-SGP-IV) of the kuruma prawn Penaeus japonicus in order to study its expression and characterize the structure of its precursor. A cDNA fragment was isolated using RT-PCR with two degenerate oligonucleotide primers that were designed based on the peptide sequence of Pej-SGP-IV, and this fragment was used as a probe to screen an eyestalk cDNA library. In a positive cDNA clone (814 base pairs (bp)), an open reading frame of 315 bp was found; the conceptually translated protein consists of a putative signal peptide (28 residues) and Pej-SGP-IV (77 residues). In Northern blot analysis using a cDNA probe, specific hybridization to a transcript of 0.95 kb was seen in RNA extracted from the eyestalk but not from hepatopancreas, abdominal muscle, brain, thoracic ganglia or abdominal ganglia. The level of the Pej- SGP-IV mRNA in the eyestalk did not change significantly during the molt cycle.
Olive, P. J. W., Rees, S. W., and Djunaedi, A. (1998). Influence of photoperiod and temperature on oocyte growth in the semelparous polychaete Nereis (Neanthes) virens. Marine Ecology-Progress Series 172, 169-183.
Environmental factors influencing the rate of oogenesis in the seasonal cycle of the semelparous polychaete Nereis (Neanthes) virens Sars have been investigated in specimens reared under commercial conditions (concrete tanks under natural light supplied with a mixture of power station heated and ambient sea water to maintain ca 18 degrees C all year round). The rate of oocyte growth is strongly influenced by the external photoperiod and the responses to static 24 h LD (light-dark) cycles have been investigated. Oocyte growth is more rapid when specimens are exposed to a 24 h LD cycle in which the photophase is below a critical value between 12 and 13 h. The critical photoperiod transition in natural environments is therefore at the autumn equinox. N. virens are able to respond to transfer between LD 16:8 h and LD 8:16 h at all times of the year, which suggests the operation of a continuously consulted system of photoperiodic control. The rate of oocyte growth in competent specimens is a linear function of the number of LD 8:16 h cycles experienced. The critical photoperiod divides the solar year into 2 nearly equal periods, with the short day period (winter) favouring oocyte growth. There is a synergism between the effects of photoperiod and seasonally reducing temperature. During the calendar winter transition to LD 8:16 h or other LD cycles below the critical value initiates rapid oocyte growth whatever the temperature but in the calendar summer this only occurs ii the external temperature is also reduced to 12 degrees C or below. The response to photoperiod and temperature is moderated by internal factors and under commercial production systems elevated rates of oocyte growth can only be achieved in females that are about 1 yr old. The oocyte growth induced by exposure to LD 8:16 h Light cycles and low temperature is similar to, but slightly less than, that induced by hormone deprivation, i.e, supra-oesophageal ganglion ablation. The results are discussed in relation to the control of seasonal cycles in Nereidae, the role of the endocrine system and in the context of the Life history theory for long lived semelparous organisms with variable age at maturity.
Osborne, N. N., and Dando, M. R. (1970). Monoamines in the stomatogastric ganglion of the lobster Homarus vulgaris. Comp Biochem Physiol 32, 327-31.
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Pahl, B. C., and Opitz, H. M. (1999). The effects of cypermethrin (Excis) and azamethiphos (Salmosan) on lobster Homarus americanus H-Milne Edwards larvae in a laboratory study. Aquaculture Research 30, 655-665.
This research assessed the effects of two chemicals, cypermethrin (Excis) and azamethiphos (Salmosan), used in the treatment of sea lice Lepeophtheirus salmonis (Kroyer) on American lobster Homarus americanus H. Milne Edwards larvae under laboratory conditions. Larvae were exposed to concentrations of 5, 0.5, 0.05, 0.005 and 0 p.p.b. cypermethrin and 100, 10, 1, 0.1 and 0 p.p.b. azamethiphos for durations of 5, 30 and 60 min, 6 and 12 h in artificial seawater. Both treatment chemicals caused significant mortality (P < 0.05) of the lobster larvae below the recommended treatment doses of 5 p.p.b. cypermethrin for Ih and 100 p.p.b. azamethiphos for Ih. Temperature affected mortality significantly (P<0.05). and interactions between treatment duration and treatment concentration were also significant (P < 0.05). LC50 values calculated for the treatment durations ranged from 0.66 to 0.058 p.p.b. at 10 degrees C and 1.69-0.365 p.p.b, at 12 degrees C for cypermethrin, and 33.9-1.3 p.p.b. at 10 degrees C and 50.4-0.9 p.p.b. at 12 degrees C for azamethiphos treatment, at the above treatment durations. The lowest LC50 values correspond to approximate to 1/90th of the recommended treatment dose for cypermethrin (Excis) at 12 degrees C and 1/14th at 10 degrees C: and 1/110th of the recommended treatment dose for azamethiphos (Salmosan) at 12 degrees C and 1/75th at 10 degrees C. The research determined Variations in observed behavioural treatment effects on lobster larvae exposed to both cypermethrin and azamethiphos (temperature x treatment duration x treatment concentration; cypermethrin P<0.001, azamethiphos P = 0.008). The pattern of effects that occurred at each temperature were, however, similar (cypermethrin P=0.764; azamethiphos P = 0.218), and 'intensity of effect' of the treatment chemicals was positively correlated with an increasing treatment concentration high (r(2)=0.915, r(2) = 0.905).
Paibulkichakul, C., Piyatiratitivorakul, S., Kittakoop, P., Viyakarn, V., Fast, A. W., and Menasveta, P. (1998). Optimal dietary levels of lecithin and cholesterol for black tiger prawn Penaeus monodon larvae and postlarvae. Aquaculture 167, 273-281.
The effect of lecithin and cholesterol on growth and survival of larval and postlarval Penaeus monodon was evaluated using semi-purified diets containing four levels of lecithin (0.0, 0.5, 1.0 and 1.5%) and three levels of cholesterol (0.0, 0.5 and 1.0%). Three early stages (zoeal, mysid and postlarval) of P. monodon were fed the experimental diets. Growth and survival of shrimp fed diets containing 1.0 and 1.5% lecithin were not significantly different(P > 0.05) but these groups had significantly greater growth and survival than those fed 0.0 and 0.5% lecithin diets. Shrimp fed diets containing 1.0% cholesterol had significantly greater (P < 0.05) growth and survival than that of shrimp fed diets containing 0.0 and 0.5% cholesterol. There was no interaction between lecithin and cholesterol on growth and survival of P. monodon. During a low salinity stress test, PL-15 shrimp fed diets containing 1.0% cholesterol had significantly greater(P < 0.05) tolerance to low salinity exposure. (C) 1998 Elsevier Science B.V. All rights reserved.
Palacios, E., Perez-Rostro, C. I., Ramirez, J. L., Ibarra, A. M., and Racotta, I. S. (1999). Reproductive exhaustion in shrimp (Penaeus vannamei) reflected in larval biochemical composition, survival and growth. Aquaculture 171, 309-321.
Penaeus vannamei larval quality in terms of biochemical composition and survival was studied throughout a spawning period. Spawns from broodstock at three different times during a commercial production period were sampled (15, 45, and 75 days after ablation). Biochemical composition of eggs, nauplii, 15-day old postlarvae (PL15), and growth and survival during culture were determined. As the days after ablation increased, a reproductive exhaustion of spawners was reflected in the energy reserves of the eggs produced. Overall larval performance during culture and survival was considerably higher in recently ablated spawners (15 days) and decreased in spawners 45 and 75 days after ablation. At PL15, a test for larval resistance to a salinity stress was applied that showed a decreased PL condition related to reproductive exhaustion of spawners: survival to stress decreased from 89% in recently ablated to 68% in larvae produced 45 days after ablation, and to 39% in larvae produced to the end of the spawning period. Nauplii condition index (NCI), calculated from nauplii triacylglycerol (TG) levels, percentage of viable nauplii, and nauplii length declined in nauplii produced with spawners sampled 45 and 75 days after ablation. This study demonstrated that reproductive exhaustion of shrimp spawners occurs and it becomes largely evident as time after ablation increases: spawner exhaustion is reflected in the quality of the larvae produced. (C) 1999 Elsevier Science B.V. All rights reserved.
Palma, A. T., Wahle, R. A., and Steneck, R. S. (1998). Different early post-settlement strategies between American lobsters Homarus americanus and rock crabs Cancer irroratus in the Gulf of Maine. Marine Ecology-Progress Series 162, 215-225.
The abundance of many invertebrates with planktonic larval stages can be determined shortly after they reach the benthos. In this study, we quantified patterns of abundance and habitat utilization of early benthic phases of the American lobster Homarus americanus and the rock crab Cancer irroratus. These 2 decapods are among the most common and abundant macroinvertebrates in coastal zones of the Gulf of Maine, with similar densities of larger individuals. Settlement and early postsettlement survival indicate that lobsters are highly substrate-specific early in life, settling predominantly in cobble beds. Crabs appear to be less selective, setting both in cobble and sand. Cumulative settlement of crabs, inferred from weekly censuses over the summer, was an order of magnitude greater than that of lobsters over the same time period. However, only crabs showed significant postsettlement losses. Although the identity of specific predators is unknown, predator exclusion experiments and placement of vacant uninhabited nursery habitat suggested that post-settlement mortality rather than emigration was responsible for these losses. The selective habitat-seeking behavior and lower post- settlement mortality of lobsters is consistent with their lower fecundity and later onset of reproductive maturity. The patterns observed for crabs, however, suggest a different strategy which is more in accordance with their higher fecundity and earlier onset of maturity. It is possible that lower fecundity but greater per-egg investment, along with strict habitat selection at settlement and lower post- settlement mortality, allows adult lobster populations to equal adult populations of crabs. This occurs despite crabs being more fecund and less habitat-selective settlers but sustaining higher postsettlement mortality.
Palma, A. T., Steneck, R. S., and Wilson, C. J. (1999). Settlement-driven, multiscale demographic patterns of large benthic decapods in the Gulf of Maine. Journal of Experimental Marine Biology and Ecology 241, 107-136.
Three decapod species in the Gulf of Maine (American lobster Homarus americanus Milne Edwards, 1837, rock crab Cancer irroratus Say, 1817, and Jonah crab Cancer borealis Stimpson, 1859) were investigated to determine how their patterns of settlement and post-settlement abundance varied at different spatial and temporal scales. Spatial scales ranged. from centimeters to hundreds of kilometers. Abundances of newly settled and older (sum of several cohorts) individuals were measured at different substrata, depths, sites within and among widely spaced regions, and along estuarine gradients. Temporal scales ranged from weekly censuses of new settlers within a season to inter-annual comparisons of settlement strengths. Over the scales considered here, only lobsters and rock crabs were consistently abundant in their early post-settlement stages. Compared to rock crabs, lobsters settled at lower densities but in specific habitats and over a narrower range of conditions. The abundance and distribution of older individuals of both species were, however, similar at all scales. This is consistent with previous observations that, by virtue of high fecundity, rock crabs have high rates of settlement, but do not discriminate among habitats, and suffer high levels of post- settlement mortality relative to lobsters. At settlement, large, habitat-scale differences exist for lobsters but not for rock crabs; these are probably the result of larval settling behavior. In contrast, patterns at the largest, inter-regional, spatial scales suggest oceanographic control of larval delivery. Increased mobility and vagility with greater body size for both species reduces demographic differences among older individuals over a range of spatial scales. (C) 1999 Elsevier Science B.V. All rights reserved.
Paquet, F., Durand, J. P., Goudard, F., Germain, P., Milcent, M. C., and Pieri, J. (1993). Distribution of [241Am] in hepato-pancreatic nuclear proteins of the lobster (Homarus gammarus). Biochem Mol Biol Int 29, 635-44.
Recent studies on the bio-accumulation of transuranic elements in marine invertebrates have demonstrated an intracellular concentration of radionuclides in the digestive gland. The present investigation aims to establish the distribution of [241Am] within the different structures of the cell nucleus. Lobsters were experimentally contaminated through feeding and then killed. The nuclei of hepato- pancreatic cells were isolated, purified and dissociated. The different protein categories were separated in media of increasing ionic strength. The distribution of americium in this material yielded results showing a preferential fixation onto the structural proteins of the nuclear matrix. The radiological consequences of such an affinity are discussed in terms of the life-times of the ligands concerned.
Paterson, B. D., and Spanoghe, P. T. (1997). Stress indicators in marine decapod crustaceans, with particular reference to the grading of western rock lobsters (Panulirus cygnus) during commercial handling. Marine and Freshwater Research 48, 829-834.
Good transport survival of western rock lobsters (Panulirus cygnus) is ensured by rigorous selection of healthy lobsters prior to packaging for transport. The rejects are attributed to stress during harvesting and handling. A major stresser, of variable severity throughout the fishery, is the storage and transport of the lobsters out of water with accompanying effects of temperature, disturbance and tail-flipping exercise on metabolic rate. Pointers to apparent fatigue or injury in weak lobsters may be found in lobster haemolymph. Published literature suggests a number of parameters that might prove to be predictors of mortality in P. cygnus, but these will have to be examined in detailed physiological studies. Information is also required from tissue metabolism and pathology to complete the picture. If the symptoms are the result of previous stress, then one obvious approach is to sample rock lobsters at key points along the harvesting and handling process, in conjunction with sampling of normal or 'baseline' lobsters and laboratory stress trials. Practical stress indicators, once identified, can be used both to test existing screening methods and in studies aimed at changing handling practices to reduce stress.
Paterson, B. D., Grauf, S. G., and Smith, R. A. (1997). Haemolymph chemistry of tropical rock lobsters (Panulirus ornatus) brought onto a mother ship from a catching dinghy in Torres Strait. Marine and Freshwater Research 48, 835-838.
For export of live Panulirus ornatus from northern Queensland, divers catch the lobsters by hand and keep them in small tanks on dinghies before draining the tanks and returning at speed to a mother ship that has a larger storage tank. The lobsters are sometimes too weak for export. The physiological state of lobsters stored in a tank on the mother ship was studied by measuring the concentrations of L-lactate, D-glucose and ammonia in the haemolymph. Oxygen levels in the dinghy tanks were normally acceptable but fell rapidly below 50% saturation when flow was stopped and the tank was draining. The concentration of lactate in the haemolymph of lobsters arriving from the dinghy was 16.4 +/- 5.7 mmol L-1 (mean +/- sn = 9); this fell during storage on the mother ship. On the mother ship, serum concentrations of calcium, potassium and magnesium ions all increased, haemolymph glucose concentration increased slightly and then decreased, and ammonia concentration did not change. Future work may identify which aspects of prior handling are responsible for the elevated lactate concentrations in captive lobsters, but improvements could be made meanwhile to water flow through the dinghy tanks.
Patton, M. L., and Grove, R. F. (1992). Statolith hair movements and the regulation of tonic gravity reflexes in the lobster, Homarus americanus. Comp Biochem Physiol Comp Physiol 101, 259-68.
1. The irregularity of the statolith of the lobster, Homarus americanus, probably causes a large and haphazard variation in the response of the individual statocyst receptors to body rotation. 2. Lobster gravity reflexes are regulated by the summed responses of the statocyst receptors; this probably compensates for the haphazard variation in the sensory input.
Patton, M. L., and Grove, R. F. (1992). The response of statocyst receptors of the lobster, Homarus americanus, to movements of statolith hairs. Comp Biochem Physiol Comp Physiol 101, 249-57.
1. While recording from the statocyst nerve of Homarus americanus, we deflected the statolith hairs from the "rest" position they assumed after the lith was removed. 2. Each of the smaller statocyst hairs apparently drove three sensory receptors; all receptors were sensitive to hair position, hair movement velocity, and hair movement direction. 3. Two of the receptors, types A and C, only responded when the hair was lifted up and away from rest; the third, type B, only responded vigorously when a hair was moved back toward rest from such a deflexion. 4. Type A and B receptors were phasic-tonic; type C receptors were phasic.
Pearce, J., Govind, C. K., and Meiss, D. E. (1985). Growth-related features of lobster neuromuscular terminals. Brain Res 353, 215-28.
Neuromuscular terminals of the low-output type formed by the single excitor axon to the limb distal accessory flexor muscle in the lobster Homarus americanus were studied with serial section electron microscopy. This type of innervation was compared between a small and a large lobster where a two-fold difference in mean quantal content of synaptic transmission was found. Several growth-related changes in the fine structure of these low-output synaptic terminals were seen. First, there was a proliferation of multiterminal innervation consisting of an increase in the number of nerve terminals, synapses and presynaptic dense bars between the small and large lobster. Also the mean surface area of the synapses increased significantly in the large compared to the small lobster. Second, synapses possessed distinct areas of non- specialized membrane or perforations which showed a growth-related increase in their number per synapse between small and large lobsters. Such perforations also occurred in the high-output synapses but only amongst the larger synapses of the older lobster. It is proposed that these perforations subdivided synapses into smaller functional units for membrane recycling as they provide a ready source of non-synaptic axolemma for nearby active sites (dense bars). Third, the branch point between subsidiary and principal terminals as well as the ending of a terminal is composed of synaptic membrane which is presumably involved respectively in the sprouting and elongation of nerve terminals during growth. Altogether these observations signify both qualitative and quantitative changes in identified neuromuscular terminals with growth.
Pearce, C. M., Gallager, S. M., Manuel, J. L., Manning, D. A., O'Dor, R. K., and Bourget, E. (1998). Effect of thermoclines and turbulence on depth of larval settlement and spat recruitment of the giant scallop Placopecten magellanicus in 9.5 m deep laboratory mesocosms. Marine Ecology-Progress Series 165, 195-215.
An experiment was conducted from December 1992 to February 1993 in a 10.5 m deep, 3.7 m diameter tank to examine the effect of thermoclines and water column turbulence on the depth of larval settlement and spat recruitment of the giant scallop Placopecten magellanicus (Gmelin). Polyethylene tube mesocosms set up within the tank were used to enclose 9.5 m deep columns of seawater which were then used as experimental replicates. Five different treatments were established as follows: (1) no turbulence and a 1.5 degrees C thermocline, (2) no turbulence and no thermal gradient, (3) low level of turbulence with a 1.5 degrees C thermocline, (4) medium level of turbulence with a 0.5 degrees C thermocline, and (5) high level of turbulence with no thermal gradient. Various turbulence levels simulated turbulent energies ranging from open oceanic environments to near-shore and coastal conditions with vertical dissipation rates ranging from 10(-7) to 10(-3) cm(2) s(-3). Ropes with collectors positioned at every 1 m depth interval were suspended the length of the water column in each replicate tube to collect settled spat. Spat counts varied significantly with both depth and turbulence treatment and were dependent on the interaction between the 2 factors. Numbers of spat generally increased with increasing depth in the static and low turbulence treatments, but this relationship became less evident with increasing turbulence; spat recruitment in the high turbulence tubes appeared random with respect to depth. It is suggested that the trend of increasing recruitment with depth in the static and low turbulence tubes was driven primarily by larval behaviour at settlement. There was no indication of increased recruitment at or above the thermocline, in contrast to a previous mesocosm experiment with a stronger thermal gradient and a different population of larvae, suggesting that stratification intensity may affect depth of larval settlement and spat recruitment. Settlement rate did not appear to be a strict function of larval encounter rate with the spat collectors. Higher spat counts in treatments with a 1.5 degrees C thermocline than in other turbulence treatments, even when results were corrected for differences in competency among the various treatments, suggest that thermal gradients have a potential commercial importance in both the collection and hatchery production of scallop spat.
Pedersen, K. L., Pedersen, S. N., Hojrup, P., Andersen, J. S., Roepstorff, P., Knudsen, J., and Depledge, M. H. (1994). Purification and characterization of a cadmium-induced metallothionein from the shore crab Carcinus maenas (L.). Biochem J 297, 609-14.
Two metallothionein variants were purified from the midgut gland of crabs (Carcinus maenas) exposed to a high cadmium concentration (2 p.p.m.). One of the variants was purified from crabs exposed to a low cadmium concentration (0.5 p.p.m.). The purification method involved acetone precipitation, gel filtration and reversed-phase h.p.l.c. The complete amino acid sequences of both variants have been elucidated by m.s. and automated sequence analysis on S-methylated proteins or fragments produced by cleavage of the S-methylated proteins with Staphylococcus aureus proteinase. The two variants from crabs exposed to the high cadmium concentration differed only by a single residue of methionine at the N-terminus. The single variant isolated from crabs exposed to the low cadmium concentration was the one without the N- terminal methionine, indicating that high cadmium concentrations either inhibit the processing enzymes and/or that the processing enzymes cannot keep pace with the increased metallothionein synthesis when cadmium availability is high. Cadmium-induced metallothionein from C. maenas shows a high degree of structural similarity to metallothioneins from the decapod crustaceans Scylla serrata and Homarus americanus.
Pedersen, S. N., Pedersen, K. L., Hojrup, P., Depledge, M. H., and Knudsen, J. (1996). Primary structures of decapod crustacean metallothioneins with special emphasis on freshwater and semi-terrestrial species. Biochem J 319, 999-1003.
Cadmium injections induced only a single form of metallothionein (MT) in the midgut gland of Potamon potamios, whereas the same treatment induced two isoforms in Astacus astacus. The only difference between the two latter isoforms was that one had an extra N-terminal methionine residue. MT from P. potamios showed structural differences from other decapod crustacean MTs. It contained a Gly-Thr motif at positions 8 and 8a, which had previously been found only in certain vertebrate and molluscan MTs. Furthermore P. potamios MT contained two to three times as many glutamic acid residues as normally found in decapod crustacean MT. The primary structure of MT from the freshwater crayfish A. astacus showed a high degree of sequence identity with MT from other decapod crustaceans, especially the marine astacidean Homarus americanus, although two valine residues were unexpectedly found at positions 8 and 21, where lysine residues are normally found.
Peeke, H. V. S., Figler, M. H., and Chang, E. S. (1998). Sex differences and prior residence effects in shelter competition in juvenile lobsters, Homarus americanus Milne- Edwards. Journal of Experimental Marine Biology and Ecology 229, 149-156.
Using a resident-intruder paradigm, a four-experiment study of competition for a single shelter between same- and mixed-sex dyads of juvenile lobsters, Homarus americanus Milne-Edwards, revealed a significantly greater advantage for male residents than female residents against intruders of either sex. However, there was no significant direct competitive advantage for residents of one sex over intruders of the other, as occurs for adult males over females in this species. There was a prior residence effect only in the male-male dyad condition. Unexpectedly, there was a reliable intruder advantage in female-female dyads. The methods employed showed that the shelter-seeking response of the juvenile lobster is a phylogenetic adaptation and that juvenile aggressive behavior differs little in form from that of adult lobsters but appears to be more intense. (C) 1998 Elsevier Science B.V. All rights reserved.
Petit, H., NegreSadargues, G., Castillo, R., and Trilles, J. P. (1997). The effects of dietary astaxanthin on growth and moulting cycle of postlarval stages of the prawn, Penaeus japonicus (Crustacea, Decapoda). Comparative Biochemistry and Physiology a-Physiology 117, 539-544.
Penaeus japonicus postlarvae reared in laboratory conditions were fed artificial diet either lacking of carotenoids (C) or supplemented with astaxanthin (A). Frozen Artemia was used as standard (S). The effects of dietary carotenoids on growth are relevant to the developmental stage of the animal as well as to the duration of the treatment. The protein content is not affected whatever the diet. Astaxanthin supplemented diet has been found to shorten the moulting cycle. Postlarvae fed pigmented diets (synthetic astaxanthin or canthaxanthin from Artemia) exhibit an ecdysteroid rate lower than that of the group receiving the control diet, extremely poor in carotenoids. (C) 1997 Elsevier Science Inc.
Petit, H., Negre-Sadargues, G., Castillo, R., Valin, S., and Trilles, J. P. (1998). The effects of dietary astaxanthin on the carotenoid pattern of the prawn Penaeus japonicus during postlarval development. Comparative Biochemistry and Physiology a-Molecular and Integrative Physiology 119, 523-527.
Penaeus japonicus postlarvae, reared under laboratory conditions, a ere fed an astaxanthin enriched diet to the investigate carotenoid metabolic capabilities during the postlarval development. Animals fed astaxanthin were found to absorb this carotenoid. The decrease of pigment concentration in the carotenoid starved group is related to the duration of the experimental feeding conditions; the carotenoid depletion depends upon the postlarval status at the starting point. As has been shown for adult prawns, the carotenoid pattern of postlarval stages, regardless of the diet, consists mainly of fret: and esterified astaxanthin; the relative amounts of these fractions undergo slight variations depending on the diet. (C) 1998 Elsevier Science Inc.
Phillips, J. W., McKinney, R. J., Hird, F. J., and Macmillan, D. L. (1977). Lactic acid formation in crustaceans and the liver function of the midgut gland questioned. Comp Biochem Physiol [B] 56, 427-33.
1. The possibility of the midgut gland of the crustacean (Cherax destructor) functioning as a liver has been investigated. 2. Seven species of crustaceans accumulate lactic acid in the haemolymph when exercised. The rate of disappearance of lactate in Homarus gammarus and in C. destructor is very slow when compared with man. 3. In the midgut gland of C. destructor no firm evidence was obtained for gluconeogenesis from lactate and for ketogenesis from fatty acids. 4. It is concluded that there is at present no justification for the common practice of calling the midgut gland an hepatopancreas.
Pickering, H., and Whitmarsh, D. (1997). Artificial reefs and fisheries exploitation: A review of the 'attraction versus production' debate, the influence of design and its significance for policy. Fisheries Research 31, 39-59.
Amidst the growing volume of published research on artificial reefs, one of the key questions concerns their potential for enhancing production over and above merely serving to attract and concentrate fish at specific sites. This paper reviews the 'attraction versus production' debate, highlighting the key role of design in determining a reefs effectiveness. Though some studies have apparently demonstrated that artificial reefs are capable of acting as production enhancers, others have not, for reasons which may be associated with the design of the reef itself. The review identifies a number of lines of enquiry for future research, and argues that while the proper design of a reef is essential to maximise productive potential, this may be of little value in the absence of a management strategy aimed at controlling the build-up of harvesting pressure which some reefs may engender. (C) 1997 Elsevier Science B.V.
Pollock, D. E. (1997). Egg production and life-history strategies in some clawed and spiny lobster populations. Bulletin of Marine Science 61, 97-109.
Important life history parameters are compared in a number of clawed and spiny lobsters. Body size, egg size and the number of spawnings per lifetime are the main determinants of lifetime egg production (E/R). Computation of the latter enables inter- specific and intergroup comparisons to be made, providing a crude method for assessing relative survival rates of the early life history phases of different groups and species. Intraspecific variations in E/R result largely from variations in size at maturity of females (L-m) and growth rates, which are positively correlated with each other. In contrast, egg size, larval size and size at settlement display little phenotypic variation and tend to be species-specific, Ln the clawed lobsters Nephrops and Homarus, relatively large egg sizes imply relatively small broods and low E/R. Significant differences in E/R between the two latter genera are mainly a function of body size, which in turn is coupled with differences in the survival strategies of the larval and postlarval stages. In spiny lobsters, high E/R values are commonly associated with relatively small egg and large body size, strategies to boost egg production which have evolved to offset high mortalities of the early life history phases. A puzzling exception to this rule exists in the case of Panulirus guttatus, a small Caribbean spiny lobster which exhibits relatively large egg size coupled with small body size and low E/R.
Pradel, L. A., and Kassab, R. (1973). [Arginine kinase from lobsters (Homarus vulgaris). New method of preparation of the enzyme]. C R Acad Sci Hebd Seances Acad Sci D 276, 2843-6.
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Prestwich, G. D., Bruce, M. J., Ujvary, I., and Chang, E. S. (1990). Binding proteins for methyl farnesoate in lobster tissues: detection by photoaffinity labeling. Gen Comp Endocrinol 80, 232-7.
Methyl farnesoate (MF) is secreted by the mandibular organs of crustaceans, but its physiological role and biochemical distribution are only partially known. Characterization of specific MF binding proteins (MFBP) in homogenates of tissues of the American lobster, Homarus americanus, was achieved by photoaffinity labeling with tritium- labeled farnesyl diazomethyl ketone (3H-FDK). The tissues selected include epidermis, tail muscle, central nervous system, eyestalk, hemolymph, hepatopancreas, ovaries, testes, and Y-organ. Both high- speed pellets and supernatants were tested. Competing ligands employed to verify specificity of light-induced covalent modification included MF, methoprene, and unlabeled FDK. A 40-kDa band was labeled strongly in the hemolymph; the labeling was displaced in the presence of a 100- fold excess of unlabeled MF. Although many other tissues had proteins which labeled with 3H-FDK, none of these showed competition by MF. This MFBP is thus functionally analogous to the hemolymph JH-binding proteins of insects.
Rabin, H. (1965). Studies on gaffkemia, a bacterial disease of the American lobster, Homarus americanus (Milne-Edwards). J Invertebr Pathol 7, 391-7.
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Ragan, M. A., Cawthorn, R. J., Despres, B., Murphy, C. A., Singh, R. K., Loughlin, M. B., and Bayer, R. C. (1996). The lobster parasite Anophryoides haemophila (Scuticociliatida: Orchitophryidae): nuclear 18S rDNA sequence, phylogeny and detection using oligonucleotide primers. J Eukaryot Microbiol 43, 341-6.
We have determined the nucleotide sequence of the nuclear gene encoding small-subunit ribosomal ribonucleic acid of the ciliate Anophryoides haemophila, a parasite of the American lobster Homarus americanus. The gene is 1763 bp in length, and has a guanosine-plus-cytosine content of 43.9%. Inferred phylogenetic frameworks strongly support the monophyly of the scuticociliates, and suggest that order Scuticociliatida should be elevated to at least subclass rank. Oligonucleotide probes based on A. haemophila ssurDNA can discriminate between DNAs of A. haemophila and other investigated hymenostome ciliates, and effectively prime polymerase chain reaction-based detection of A. haemophila deoxyribonucleic acid against at least a 1600-fold excess of total deoxyribonucleic acid from H. americanus. GENBANK/U51554.
Regenstein, J. M. (1977). Lobster (Homarus americanus) striated muscle myosin. Comp Biochem Physiol [B] 56, 239-44.
1. Myosin from the thin-filament regulated flexor muscle of lobster contains 2 moles of each of 2 light chains. 2. The Lb 1 light chain of 19,000 daltons which can be removed by DTNB is heavier than the DTNB light chain of chicken. The Lb 2 light chain of 17,000 daltons can be removed with urea. 3. On electrophoresis in 8 M urea (pH 8.7) the Lb 2 light chain migrates with a mobility similar to that of chicken A2, but the Lb 1 migrates significantly faster than any of the chicken light chains. 4. In lobster, the DTNB treatment destroys the Ca and K-EDTA ATPase activity of lobster myosin.
Regnouf, F., Pradel, L. A., Kassab, R., and Nguyen Van, T. (1969). [Carboxyl terminal structure of ATP:L-arginine phosphotransferases of molecular weight 43,000 (Homarus vulgaris) and 86,000 (Sipunculus nudus)]. Biochim Biophys Acta 194, 540-7.
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Reiber, C., McMahon, B., and Burggren, W. (1997). Cardiovascular functions in two macruran decapod crustaceans (Procambarus clarkii and Homarus americanus) during periods of inactivity, tail flexion and cardiorespiratory pauses. J Exp Biol 200, 1103-13.
Arterial hemolymph flow was measured in restrained crayfish (Procambarus clarkii) and lobsters (Homarus americanus). Implanted pulsed Doppler flow transducers were used to measure arterial flows in the anterior aorta, posterior aorta, sternal artery, lateral artery, ventral thoracic artery and ventral abdominal artery, allowing determination of flow simultaneously in several arteries over a period of 4 days. Calculated Doppler hemolymph flow showed a strong correlation (P0.05) with 'pumped' hemolymph flow as determined by in situ calibration. Arterial flow patterns remained constant during quiet conditions. In crayfish, cardiac output was 7.5±1.1 ml min- 1 (252 ml kg-1 min-1), of which the anterior aorta received 1.3±0.15 ml min-1 (20.1±4.0 %), the posterior aorta received 0.8±0.1 ml min-1 (12.3±2.7 %) and the sternal artery received 5.2±1.4 ml min-1 (67.5±37.0 %). Mean heart frequency at rest was 125.6±5.2 beats min-1 and stroke volume was 0.06±0.01 ml beat-1 (1.98 ml kg-1 beat-1). In lobsters, cardiac output was 60.8±4.4 ml min-1 (93.6±6.8 ml kg-1 min-1), with the anterior aorta receiving 7.8±0.8 ml min- 1 (12.8±2.7 %), the lateral arteries receiving 0.6±0.2 ml min-1 (1.0±0.5 %), the posterior aorta receiving 12.6±1.0 ml min-1 (20.7±3.3 %) and the sternal artery receiving 38.9±4.1 ml min-1 (64.0±13.4 %). Flows in the branches of the sternal artery were 0.3±0.05 ml min-1 (0.5±2 %) in the ventral abdominal artery and 4.0±0.1 ml min-1 (6.5±0.3 %) in the ventral thoracic artery. Lobster heart rate was 82.5±2.9 beats min-1 and stroke volume was 0.7±0.05 ml beat-1. Periods of constant hemolymph flow were interrupted by tail flexions (abdominal flexion) and, in lobsters, periods of cardiac/respiratory pause. Tail movement increased flow (peak height and minimum flow values) in both crayfish and lobsters, although the general wave form of hemolymph flow and pressure did not change. In lobsters, periodic respiratory pauses were observed during which all arteries received hemolymph, despite the low heart rate.
Reiber, C. L., and McMahon, B. R. (1998). The effects of progressive hypoxia on the crustacean cardiovascular system: A comparison of the freshwater crayfish, (Procambarus clarkii), and the lobster (Homarus americanus). Journal of Comparative Physiology B-Biochemical Systemic and Environmental Physiology 168, 168-176.
The heart rate of crayfish (Procambarus clarkii) and lobsters (Homarus americanus) decreased (bradycardia) as partial pressure of O-2 (Po-2) decreased, yet cardiac output (V-b) was maintained via an increased stroke volume (S-v) to Po(2)s of 40 mmHg and 75 mmHg for crayfish and lobsters, respectively. V-b was redistributed in both animals. Flow through the anterior aorta increased while flow dropped through the posterior aorta and sternal artery to a Po-2 of 30 mmHg; below this flow was no longer maintained in crayfish. In the lobster, flow increased to the lateral arteries and the ventral thoracic artery while flow through the anterior and posterior aortas, sternal artery and ventral abdominal artery decreased to a Po-2 of 75 mmHg. Anterior hemolymph flow was maintained or increased in both animals presumably to supply nervous tissue and cephalic sense organs better. Crayfish showed an increase in intracardiac and mean arterial hemolymph pressures as Po-2 declined. The increased pressures combined with the net increase in cardiac filling pressure and diastolic filling time could have accounted for The increased S-v. The cardiovascular response exhibited by both the crayfish and lobster was Po-2 dependent, below a critical water Po-2 active compensation was no longer observed.
Resch-Sedlmeier, G., and Sedlmeier, D. (1999). Release of digestive enzymes from the crustacean hepatopancreas: effect of vertebrate gastrointestinal hormones. Comparative Biochemistry and Physiology B-Biochemistry & Molecular Biology 123, 187-192.
Vertebrate gastrointestinal hormones were tested on their ability to liberate digestive enzymes from the crustacean midgut gland. CCK-8 (desulfated form), gastrin, bombesin, secretin, and substance P were detected to release enzymes. Maximal concentrations observed were 5 nM CCK for protease release, 1 nM gastrin for protease and 100 nM for amylase release, 100 nM bombesin for protease release, 10 nM secretin for amylase and protease release. and 100 nM substance P for protease release. Unlike in vertebrates, glucagon was unable to stimulate enzyme release in crustaceans, this also applies to the counterpart insulin. These results may support the assumption that Crustacea possess endogenous factors resembling the above mentioned vertebrate hormones, at least in such a way that the appropriate receptors have the capacity to accept these hormones. (C) 1999 Elsevier Science Inc. All rights reserved.
Richards, K. S., Miller, W. L., and Marder, E. (1999). Maturation of lobster stomatogastric ganglion rhythmic activity. Journal of Neurophysiology 82, 2006-2009.
The stomatogastric ganglion of the adult lobster, Homarus americanus generates extremely regular pyloric rhythms with a characteristic period of 0.5-1.5 Hz. To study the changes in the pyloric rhythm during embryonic and larval development, we recorded excitatory junctional potentials evoked by lateral pyloric (LP) neuron activity. Early in development the motor discharge of the LP neuron was often irregular, preventing use of conventional analysis methods that rely on extracting burst times to calculate cycle frequency and its variability. Instead, cycle frequency was determined for the LP neuron from the peak of the power spectrum obtained from the occurrence times of excitatory junctional potentials in the pi muscle. The ratio of the power in the peak to the power from 0 to 3 Hz was used as a relative measure of the regularity of the rhythm. Throughout embryonic and the first larval stage, LP neuron activity is slow, irregular, and only weakly periodic. The regularity of the rhythm increased during midlarval stages, and both the frequency and regularity increased considerably by the postlarval stage LN.
Richey, B., Decker, H., and Gill, S. J. (1985). Binding of oxygen and carbon monoxide to arthropod hemocyanin: an allosteric analysis. Biochemistry 24, 109-17.
The binding of oxygen and carbon monoxide to hemocyanin from the mangrove crab Scylla serrata and the lobster Homarus americanus has been studied by thin-layer optical absorption and front face fluorescence techniques. Three types of experiments were performed on subunit and oligomeric preparations of each hemocyanin: oxygen binding, carbon monoxide binding, and oxygen-carbon monoxide competition studies. The results obtained from the subunit preparations of dissociated oligomers from both hemocyanins show that the binding site can be ligated by either one oxygen or one carbon monoxide. The binding results obtained with the oligomeric samples of hemocyanin from both species cannot be described by the two-state MWC model [Monod, J., Wyman, J., & Changeux, J. P. (1965) J. Mol. Biol. 12, 88-118] since the data from the three types of binding experiments cannot be fit with a single set of binding constants. The MWC model has been extended by including a third allosteric form, and an analysis based on the three- state model is able to fit the data from the three types of experiments with the same set of binding constants. The comparison of the oxygen to carbon monoxide affinity ratios (kO2/kCO) indicates that the structure around the binding site of subunits in the T form oligomer is similar to that of the free subunits. The oligomeric forms of both these hemocyanins bind carbon monoxide with a weak but definite positive cooperativity. An analysis of the affinity ratios for the T, S, and R forms suggests that the high affinity of the R form results from a specific interaction between oxygen and binding site.
Riley, L. G., and Tsukimura, B. (1998). Yolk protein synthesis in the riceland tadpole shrimp, Triops longicaudatus, measured by in vitro incorporation of H-3- leucine. Journal of Experimental Zoology 281, 238-247.
Investigation of reproductive control within the tadpole shrimp, Triops longicaudatus, required the isolation and characterization of the yolk protein (vitellin, Vn). To this end, tadpole shrimp were cultured in environmental chambers (29 degrees C-22 degrees C, with 14:10 light:dark cycle). Desiccated cysts hatched in 2-3 days after inundation. The tadpole shrimp began egg deposition 7 to 8 days after hatching and exhibited a mean growth rate of 1.85 +/- 0.24 mm/day. It was observed that 4-day-old shrimp had visible eggs in their ovaries. In addition, Vn was isolated and characterized from reproductive animals, resolving as one protein on native PAGE, and possessing a molecular weight (MW) of 376,000 +/- 2,900 as determined by FPLC. Examination by SDS-PAGE revealed that Vn is composed of a single molecule with a MW of 214,000 +/- 2,000. Methyl farnesoate (MF), a crustacean compound whose role in reproduction is still being elucidated and is structurally similar to juvenile hormone III (JH III) was incubated with ovarian explants. These explants were incubated for 24 h at room temperature in EAGLE's medium adjusted to Van Harreveld's solution in six concentrations (1 pM to 100 nM) of MF and JH III. Methyl farnesoate and JH III had no direct in vitro effect on yolk protein synthesis (P less than or equal to 0.545 and P less than or equal to 0.815, respectively). (C) 1998 Wiley- Liss, Inc.
Robertson, R. M., and Laverack, M. S. (1979). Oesophageal sensors and their modulatory influence on oesophageal peristalsis in the lobster, Homarus gammarus. Proc R Soc Lond B Biol Sci 206, 235-63.
The musculature and innervation of the oesophagus of Homarus gammarus are described as a prerequisite to studies on the mechanisms and control of food ingestion. Of particular interest are two paired sensors (the anterior and posterior oesophageal sensors) which are bilaterally situated at the oesophageal-cardiac sac valve. These are similar to contact chemoreceptors previously described in insects and are classified as such on morphological grounds and with indirect electrophysiological evidence. Oesophageal peristalsis is effected by the coordinated contraction of the Oesophageal musculature. This is controlled by rhythmical bursting neuronal activity, which can be recorded from the nerve trunks in the area. A characteristic burst recorded from the superior oesophageal nerve is used as an indication of oesophageal dilatation during peristalsis for studies on the feedback effects of the oesophageal sensors. Electrical and chemical stimulation of the posterior oesophageal sensors can initiate and increase the frequency of oesophageal peristalsis, while stimulation of the anterior oesophageal sensors can slow and terminate oesophageal peristalsis. The results are discussed and a model presented of the role of the oesophageal sensors in feeding.
Robertson, R. M., and Laverack, M. S. (1979). The structure and function of the labrum in the lobster Homarus gammarus (L.). Proc R Soc Lond B Biol Sci 206, 209-33.
The labrum of decapod crustaceans is a soft lobe overhanging the mouth. The labral skeleton, musculature and innervation of Homarus gammarus are described. There are three bilateral groups of sensory neurons innervating the floor, lobe and lateral walls of the labrum. These are probably responsible for the phasic afferent activity that can be recorded from the inner labral nerve on mechanical deformation of the labrum. The labrum undergoes rhythmical retraction-protraction movements during ingestion and is shown to be active during both mandibular activity and oesophageal peristalsis. Studies were made on the duration and frequency of labral "swallowing" activity. The role of the labrum in feeding is discussed.
Robertson, R. M., and Moulins, M. (1981). A corollary discharge of total foregut motor activity is monitored by a single interneurone in the lobster Homarus gammarus. J Physiol (Paris) 77, 823-7.
1. In Homarus, an identified interneurone (the L cell), which possesses the largest cell body in the commissural ganglion and projects to the brain, exhibits a complex firing pattern (Fig. 2 a). 2. It is shown that the L cell discharges with each of the 4 pattern generators of the stomatogastric nervous system which organize the rhythmic motor activity of the foregut (Fig. 2 b-e). 3. Manipulation of the membrane potential of the L cell does not induce any change in the 4 rhythms (Fig. 3), and it is concluded that the L cell is driven by the 4 pattern generators. 4. The functional meaning of this complex corollary discharge of the total foregut motor activity is discussed.
Robertson, R. M., and Moulins, M. (1981). Control of rhythmic behaviour by a hierarchy of linked oscillators in crustacea. Neurosci Lett 21, 111-6.
In Homarus, the central pattern generators for the rhythmic motor activities of the gastric teeth and the pyloric chamber are located in the stomatogastric ganglion. It is shown that independent gastric and pyloric oscillators are also contained in higher nervous centres (the commissural ganglia) and provide a phasic rhythmic input to the stomatogastric pattern generators. This demonstrates that rhythmic behaviour can be organized by a hierarchy of linked oscillators each capable of producing the rhythm.
Rochette, R., Maltais, M. J., Dill, L. M., and Himmelman, J. H. (1999). Interpopulation and context-related differences in responses of a marine gastropod to predation risk. Animal Behaviour 57, 977-987.
We conducted laboratory experiments to investigate interpopulation differences in the behavioural responses of the whelk Buccinum undatum to the predatory lobster Homarus americanus and the asteroid Leptasterias Polaris, both in the absence and presence of feeding opportunities. Whelks from three populations in the eastern North Atlantic (1) responded to lobsters by displaying avoidance behaviours (burrowing in the sediments or retreating inside their shell), (2) responded to asteroids by displaying escape responses (rapid crawling, shell rocking behaviour or foot contortions), and (3) more often refrained from feeding in the presence of a lobster than in the presence of an asteroid. Although whelks from the three populations responded similarly to lobsters and asteroids, interpopulation differences were evident. Thus, whelks from populations sympatric with a given predator more frequently displayed 'appropriate' antipredator behaviours (i.e. avoidance in the presence of a lobster, and escape in the presence of an asteroid) than did whelks allopatric with that predator. Also, whelks from a population sympatric with both predators fed less readily in the presence of a given predator than did whelks allopatric with that predator. However, the presence of a lobster or an asteroid had the same impact on the feeding response of whelks from two populations with contrasting predator fields, one sympatric with lobsters, but allopatric with asteroids, and one sympatric with asteroids, but allopatric with lobsters. The results of our study indicate that coexistence (over evolutionary or ecological time) with lobsters and asteroids increases the propensity of the whelk to display avoidance and escape behaviours in the presence of lobsters and asteroids, respectively, but has a less predictable effect on how whelks trade off predation risk and food acquisition. Studies are needed to investigate the roles of nheritance and experience on the development of antipredator behaviours and decision making by prey animals when predation risk conflicts with other fitness-related activities such as the acquisition of food or reproductive opportunities. (C) 1999 The Association for the Study of Animal Behaviour.
Rose, R. A., Wilkens, J. L., and Walker, R. L. (1998). The effects of walking on heart rate, ventilation rate and acid-base status in the lobster Homarus americanus. Journal of Experimental Biology 201, 2601-2608.
American lobsters Homarus americanus were exercised on an underwater treadmill at speeds from 1.7 to 8 m min(-1) to determine the effects of exercise on heart rate, ventilation rate and acid-base status. Heart and ventilation rates showed almost instantaneous increases at the start of exercise, but the magnitude of the increase was not related to speed. Maximum heart rate was approximately 80-90 beats min(-1) and maximum ventilation rate was 175-180 beats min-l at all speeds tested. Exercise at all speeds caused a decrease in haemolymph pH, with the acidosis after exercise at 8 m min(-1) being significantly greater than at the other three speeds. Concomitant with this acidosis was a large increase in partial pressure of carbon dioxide, with the largest increase occurring after exercise at 8 m min(-1). The concentration of lactate in the haemolymph increased to similar levels at all speeds of walking. Davenport analysis indicates that the acidosis was predominantly respiratory in nature, Although it was anticipated that heart and ventilation rates would show increases proportional to the speed of exercise, this was not the case. Rather, the responses were fixed regardless of walking speed. The reason for this phenomenon remains unexplained.
Roustan, C., Terrossian, E. d., and Pradel, L. A. (1970). The essential thiol group of arginine kinase from Homarus vulgaris muscle studied by difference spectrophotometry and N-ethyl-[1-14C] maleimide labelling. Eur J Biochem 17, 467-71.
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Roustan, C., Pradel, L. A., Kassab, R., and Van Thoai, N. (1971). Studies on the partial exchange and overall reactions catalyzed by native and modified arginine kinase from Homarus vulgaris muscle. Biochim Biophys Acta 250, 103-16.
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Rowat, P. F., and Selverston, A. I. (1997). Synchronous bursting can arise from mutual excitation, even when individual cells are not endogenous bursters. J Comput Neurosci 4, 129-39.
Mutual excitation between two neurons is generally thought to raise the excitation level of each neuron or, if they are both bursty, to act to synchronize their bursts. If only one is bursty, it can induce synchronized bursts in the other cell. Here we show that two nonbursty cells can be induced to burst in synchrony by mutual excitatory synaptic connections, provided the presynaptic threshold for graded synaptic transmission at each synapse is at a different level. This mechanism may operate in a recently discovered network in the lobster Homarus gammarus. By a duality between presynaptic threshold and injected current, we also show that two identical, nonbursty, mutual excitatory cells could be induced to burst in synchrony by injecting differing amounts of current in the two cells. Finally we show that differential oscillations between two mutual excitatory cells could be stopped by a slow-tailed hyperpolarizing current pulse into one cell or a slow-tailed depolarizing pulse into the other.
Rudolph, A. S., and Crowe, J. H. (1985). Membrane stabilization during freezing: the role of two natural cryoprotectants, trehalose and proline. Cryobiology 22, 367-77.
The relative effectiveness of two natural cryoprotectants, proline and trehalose, in preserving membrane structure and function during freezing was studied. Isolated vesicles of sarcoplasmic reticulum (SR) from lobster muscle (Homarus americanus) were employed to study changes in structure and function during rapid freeze-thaw conditions. Both proline and trehalose were shown to effectively preserve the structure (assessed with freeze fracture) and function (assessed by the ability of the membranes to transport calcium) in the frozen vesicles. As a first step toward determining the mechanism of cryoprotection by these compounds, we have investigated their effectiveness in inhibiting freezing induced fusion between phospholipid vesicles. Pamiltoyloleoyl- phosphatidylcholine: phosphatidylserine (85:15 mole ratio) small unilamellar vesicles (SUVs) were made incorporating one of the following fluorescent probes, and energy donor, cholesteryl anthracene- 9-carboxylate, or an energy acceptor, nitrobenzo-2-oxa-1,3-diazole phosphatidylethanolamine to investigate the amount of membrane mixing during rapid freeze-thaw cycles, and storage at -20 degrees C. Membrane mixing was measured as an energy transfer from donor to acceptor when donor vesicles and acceptor vesicles were mixed before a particular freezing treatment. Membrane mixing was correlated with structural changes in these membranes by freeze-fracture analysis. Both trehalose and proline were found to be more effective in preventing membrane mixing between SUVs than the standard protectants, glycerol and dimethylsulfoxide.
Sagi, A., Khalaila, I., Abdu, U., Shoukrun, R., and Weil, S. (1999). A newly established ELISA showing the effect of the androgenic gland on secondary-vitellogenic-specific protein in the hemolymph of the crayfish Cherax qundricarinatus. General and Comparative Endocrinology 115, 37-45.
A quantitative enzyme-linked immunosorbent assay (ELISA) was developed to monitor the onset of secondary vitellogenesis in Cherax quadricarinatus females and in intersex individuals (having both male and female reproductive systems) after removal of the androgenic gland (AG). As a prerequisite for the assay, the 106-kDa polypeptide was separated from newly laid C. quadricarinatus eggs by SDS-PAGE, and anti-106-kDa antibody was raised in rabbit. The specificity of the anti-106-kDa polypeptide for proteins specific for the hemolymph of secondary-vitellogenic females was confirmed by double immunodiffusion and immunoblot cross-reactivity tests. A characteristic standard ELISA curve, using egg high-density lipoprotein (HDL), showed linearity between 16 and 500 ng (r = 0.953) and was sensitive for amounts as low as 8 ng. The inter- and intraassay coefficients of variance were 14.8 and 7.2%, respectively. Only traces of egg HDL equivalents were detected in the hemolymph of male and primary-vitellogenic females (11 to 110 mu g/ml), confirming the specificity of the assay, whereas high levels of such a protein (8-35 mg/ml) were detected in the hemolymph of secondary-vitellogenic females. Removal of the AG from intersex individuals leads to a significant increase in the concentration of vitellogenic- specific protein in the hemolymph (up to 2 mg/ml). Moreover, a significantly lower concentration was found in females subjected to AG transplant (79.3 mu g/ml). The ELISA thus provided an accurate and sensitive tool to investigate the influence of the AG on the expression of a vitellogenic- specific protein in female and intersex C. quadricarinatus, confirming the central role of this gland in tuning sexual plasticity in this species. (C) 1999 Academic Press.
Salares, V. R., Young, N. M., Bernstein, H. J., and Carey, P. R. (1979). Mechanisms of spectral shifts in lobster carotenoproteins. The resonance Raman spectra of ovoverdin and the crustacyanins. Biochim Biophys Acta 576, 176-91.
Resonance Raman data have been used to elucidate the mechanisms of the absorption spectral shifts occurring for astaxanthin upon binding to the carotenoproteins, ovoverdin and alpha-,beta- and gamma- crustacyanins, from the lobster Homarus americanus. Although distinguishable on the basis of small differences in their resonance Raman spectra the binding sites of the crustacyanins, giving rise to lambdamax at 605 +/- 25 nm, are essentially the same. The large red shift in lambdamax for the crustacyanins compared to free astaxanthin (lambdamax 480 nm), is accounted for by a charge-polarisation mechanism in which charged groups and possibly hydrogen bonds in the binding site set up pi electron polarisation in the ligand. Several alternate mechanisms can be eliminated. Ovoverdin is found to consist of three polypeptide chains of molecular weight 105,000, 95,000 and 78,000 which are not linked by disulfide bridges. The visible absorption peaks of ovoverdin at 460 and 640 nm are shown to arise from two astaxanthin molecules each bound at a different site. The spectral characteristics of the 460 nm site suggest a rigid hydrophobic environment for astaxanthin, in which no charge-ligand interactions occur. The mechanism of the spectral shift in the 640 nm site is the same as in the crustacyanins, i.e. a charge-polarisation effect. Resonance Raman spectra of ovoverdin and the crustacyanins could be obtained in situ; they were identical to the spectra of the purified proteins showing that the carotenoid sites were unperturbed by protein isolation.
Sanders, B. (1983). Insulin-like peptides in the lobster Homarus americanus. III. No glucostatic role. Gen Comp Endocrinol 50, 378-82.
Lobsters contained insulin immunoreactivity ranging from 3.4 +/- 0.6 to 7.2 +/- 0.5 microU ml-1 hemolymph. Experimental results indicated that the hemolymph insulin immunoreactive peptides have no glucostatic function. With an increase in exogenous glucose in the hemolymph no increase in hemolymph immunoreactive insulin was observed. Also, injection of hepatopancreas extract did not increase the rate of glucose removal from the hemolymph.
Sanders, B. (1983). Insulin-like peptides in the lobster Homarus americanus. II. Insulin- like biological activity. Gen Comp Endocrinol 50, 374-7.
The in vitro incorporation of [14C]glucose into glycogen in lobster muscle was used to measure insulin-like biological activity. Glycogenesis was significantly increased by the same hepatopancreas eluate which was previously found to have the greatest insulin immunoreactivity. Hemolymph but not gut extract also increased the rate of glycogenesis.
Sanders, B. (1983). Insulin-like peptides in the lobster Homarus americanus. I. Insulin immunoreactivity. Gen Comp Endocrinol 50, 366-73.
Experiments were conducted to determine if insulin-like peptides are present in the lobster Homarus americanus. Peptides were found that bind specifically to bovine insulin antibodies in a modified vertebrate radioimmunoassay. Extracts of whole hepatopancreas, gut, and hemolymph contained insulin immunoreactivity (IRI) concentrations of 67.5, 14.0, and 11.0 ng, respectively, per 700-g lobster. No insulin immunoreactivity was detected in neurosecretory cells of the eyestalk. The highest immunoreactivity was measured in the hepatopancreas, in the same fractions of eluate which contained the highest immunoreactivity when a bovine insulin standard was passed through the same chromatographic column.
Sauter, A., Staudenmann, W., Hughes, G. J., and Heizmann, C. W. (1995). A novel EF-hand Ca(2+)-binding protein from abdominal muscle of crustaceans with similarity to calcyphosine from dog thyroidea. Eur J Biochem 227, 97-101.
The amino acid sequence of a novel EF-hand Ca(2+)-binding protein from the abdominal muscle of the crayfish, Orconectes limosus, has been elucidated by tandem mass spectrometry and automated Edman degradation. The name CCBP-23 (23-kDa crustacean Ca(2+)-binding protein) is proposed. The protein can also exist as a disulfide-linked homodimer. The sequence of the monomeric form spans 200 residues with an acetylated N-terminal Ser and reveals four EF-hand domains. The 174- mass-unit difference between the calculated average molecular mass of 22,669.6 Da deduced from the sequence and the obtained electrospray ionization mass spectroscopy (ESI-MS) mass of 22,844 Da has not yet been explained. Partial sequence analysis (137 residues) of CCBP-23 from the lobster, Homarus americanus, showed a sequence identity of 74% with the crayfish protein. Homology searches revealed a 44% sequence identity of CCBP-23 from crayfish to calcyphosine, a Ca(2+)-binding protein from dog thyroidea (Lefort et al., 1989). Although CCBP-23 also shows a 44% identity to R2D5 antigen (Nemoto et al., 1993), we believe that both proteins represent two distinct subgroups within the family of EF-hand proteins.
Savagaon, K. A., and Sreenivasan, A. (1975). Purification and properties of latent and iso-enzymes of phenoloxidase in lobster (Panulirus homarus Linn.). Indian J Biochem Biophys 12, 94-9.
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Savagaon, K. A., and Sreenivasan, A. (1975). Purification and properties of pre-phenoloxidase activating enzyme in lobster (Panulirus homarus Linn.). Indian J Biochem Biophys 12, 89-93.
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Saver, M. A., Wilkens, J. L., and Airriess, C. N. (1998). Proctolin affects the activity of the cardiac ganglion, myocardium, and cardioarterial valves in Carcinus maenas hearts. Journal of Comparative Physiology B-Biochemical Systemic and Environmental Physiology 168, 473-482.
The decapod crustacean heartbeat is initiated by the cardiac ganglion and is regulated by a variety of neuronal and hormonal inputs. In this paper we examine the effects of the peptide hormone proctolin which appears to have multiple sites of action in the shore crab, Carcinus maenas. To examine some of the potential sites of proctolin action we used three heart preparations: in situ intact and open hearts, and isolated hearts. We provide evidence in support of the hypothesis that proctolin affects cardiac activity at many levels. It acts at the cardiac ganglion to modulate burst rate and at the myocardium to alter contractile force. We calculated the relationship between contractility and ganglionic output of in situ hearts as the ratio of ventricular pressure or tension to amplitude of the electromyogram or intracellular excitatory junction potential. Large proctolin-induced changes in this ratio, which could not be accounted for by ganglionic output, membrane potential or input resistance suggest direct action on the myocardium. The greater increases in ventricular pressure than in tension in the in situ hearts may reflect proctolin- induced contraction of the cardioarterial valves. Finally, proctolin can possibly influence heart rate by action on the cardioregulatory nerves of the central nervous system.
Saver, M. A., and Wilkens, J. L. (1998). Comparison of the effects of five hormones on intact and open heart cardiac ganglionic output and myocardial contractility in the shore crab Carcinus maenas. Comparative Biochemistry and Physiology a-Molecular and Integrative Physiology 120, 301-310.
The effects of five pericardial organ hormones (5- hydroxytryptamine, octopamine, dopamine, proctolin, and crustacean cardioactive peptide) were surveyed on intact and open Carcinus maenas heart preparations. The major goal of this study was to gain insight into the delicate balance of hormone action on the intact heart and cardiovascular system. Secondarily, we hoped to comment on the possible sites of hormonal action. Each hormone increased heart rate and extracellular electromyogram amplitude in a characteristic way. Changes in heart rate reflected changes in cardiac ganglion burst rate. Heart contractility, measured in intact hearts as ventricular pressure and in open hearts as isometric tension, could arise directly from the myocardioum or via changes in neural drive. Proctolin increased pressure to a greater extent than tension. Although we did not directly test proctolin effects on the cardiac ganglion, myocardium, cardioarterial valves, arterial resistance, or CNS regulatory nerves, our data led us to suggest that proctolin may have multiple sites of action on these hearts. Finally, we were interested in determining the time course of hormone action on in situ heart preparations. We found that responses to peptides were faster in onset and recovery than the amines. This study provides an overview of how several hormones act to modulate heart rate and contractility. (C) 1998 Elsevier Science Inc. All rights reserved.
Saver, M. A., Wilkens, J. L., and Syed, N. I. (1999). In situ and in vitro identification and characterization of cardiac ganglion neurons in the crab, Carcinus maenas. Journal of Neurophysiology 81, 2964-2976.
The aim of this study was to investigate the intrinsic membrane properties and hormonal responses of individual central pattern generating neurons in the cardiac ganglion of the shore crab Carcinus maenas. Because the cardiac ganglion in this crustacean species is buried within the heart musculature and is therefore inaccessible for direct morphological and electrophysiological analysis, we developed two novel in vitro preparations. First, to make the ganglion accessible, Lye established a brief enzymatic treatment procedure that enabled us to isolate the entire cardiac ganglion, in the absence of muscle tissue. Second, a cell culture procedure was developed to isolate individual neurons in vitro. With the use of both isolated ganglionic and neuronal cell culture techniques, this study provides the first direct account of the neuroanatomy of the cardiac ganglion in shore crabs. We demonstrate that cultured neurons not only survived the isolation procedures, but that they also maintained their intrinsic membrane and transmitter response properties, similar to those seen in the intact ganglion. Specifically, we tested the peptides proctolin, crustacean cardioactive peptide. the FLRFamide- related peptide F2, and an amine (serotonin) on both isolated ganglion and in vitro culture neurons. We measured changes in neuronal bust rate, burst amplitude, pacemaker slope, and membrane potential oscillation amplitude in response to the above four hormones. Each hormone either increased neuronal activity in spontaneously bursting neurons, or induced a bursting pattern in quiescent cells. The in vitro cell culture system developed here now provides us with an excellent opportunity to elucidate cellular, synaptic and hormonal mechanisms by which cardiac activity is generated in shore crabs.
Saxena, V. P., Kegeles, G., and Kikas, R. (1976). Volume of reaction by the Archibald ultracentrifuge method (lobster hemocyanin). Biophys Chem 5, 161-4.
Samples of lobster hemocyanin (Homarus americanus) under conditions of reversible reaction between whole (25 S) and half (17 S) molecules have been subjected to accurately known nitrogen pressures in analytical ultracentrifuge cells. A modified pressurization chamber of the type developed by Schumaker and colleagues has been constructed for this purpose. The molecular weight was then determined at the top (liquid- gas) meniscus, by means of the Archibald method. The logarithmic dependence upon pressure of the derived equilibrium constant then gave directly the volume of reaction. Experiments were performed in veronal- citrate buffers at pH 8, where the molar volume of formation of whole (dodecameric) molecules from half molecules appears to be negative, and at pH 8.46 in veronal-citrate buffer in the presence of 0.003 molar free calcium ion, where the molar volume of formation was estimated to be + 390 cm3/mole. In glycine-sodium hydroxide buffer at pH 9.6 containing 0.0047 molar free calcium, the molar volume of formation of whole molecules was estimated to be +120 +/- 70 cm3, corresponding to an estimated difference in partial specific volume between whole molecules and half molecules of only 1.3 (10)-4cm3/gram. The correctness of the sign of this value in glycine buffer has been verified by pressure-jump light-scattering experiments.
Scheibling, R. E., Hennigar, A. W., and Balch, T. (1999). Destructive grazing, epiphytism, and disease: the dynamics of sea urchin - kelp interactions in Nova Scotia. Canadian Journal of Fisheries and Aquatic Sciences 56, 2300-2314.
We measured the rate of advance of urchin (Strongylocentrotus droebachiensis) feeding aggregations (fronts) as they destructively grazed kelp beds (Laminaria longicruris) at both a wave-exposed site and a sheltered site in Nova Scotia over 3.5 years. The grazing fronts were composed of high densities of large adults (up to 98 and 70 per 0.25 m(2) at the exposed and sheltered sites, respectively). Urchins in the recently formed barrens, or in adjacent kelp beds, occurred at much lower densities and consisted mainly of juveniles. The fronts moved onshore into shallower water at each site, but their rate of advance varied markedly between sites and over time at each site, ranging from 0 to 4 m.month(-1). The rate of advance of a front was related to the biomass of urchins; fronts did not advance below a threshold biomass of similar to 2 kg.m(-2). Infestations of kelp by an epiphytic bryozoan (Membranipora membranacea) caused marked reductions in kelp canopy cover and biomass during winter, but the canopy regenerated through recruitment of juvenile sporophytes in spring. A localized outbreak of disease decimated S. droebachiensis at the exposed site in 1993, which enabled kelp to recolonize the barrens. Surviving urchins gradually reaggregated and resumed destructive grazing after similar to 1.5 years. A recurrence of disease in 1995 eliminated urchins at both sites and terminated the transition from kelp beds to barrens on a coastal scale. Our findings have important implications for the management of the urchin fishery, which targets grazing fronts for harvesting.
Schmid, A., and Becherer, C. (1999). Distribution of histamine in the CNS of different spiders. Microscopy Research and Technique 44, 81-93.
Immunohistochemistry is used to demonstrate histamine- immunoreactivity in the CNS of spiders. We found histamine- immunoreactivity in the photoreceptors of different spiders. Therefore, we suggest that histamine is a neurotransmitter of photoreceptors in all arthropods, since it is also known to occur in the photoreceptors of the other main arthropod taxa (Merostomata, Crustacea, and Insecta). We also describe a system of only six omnisegmental histamine-immunoreactive neurons within the central nervous system. These histamine- immunoreactive neurons can be divided into two subgroups: a dorsal system with two cells per hemisphere and a ventral system with only one cell per hemisphere. All six cells have extended arborizations in both the motor and the sensory areas of all neuromeres in the suboesophageal ganglionic mass. In contrast to araneomorph spiders, two additional sets of histamine-immunoreactive neurons were detected in mygalomorph spiders. The first set consists of seventeen cells with their cell bodies located in the cheliceral ganglion and projecting to central areas of the protocerebrum. The second set contains many if not all sensory projections from the tarsal organs on all eight legs and the pedipalps to the Blumenthal neuropil. Microsc. Res. Tech. 44:81-93, 1999. (C) 1999 Wiley-Liss, Inc.
Schmidt, M. (1997). Distribution of centrifugal neurons targeting the soma clusters of the olfactory midbrain among decapod crustaceans. Brain Res 752, 15-25.
To determine the distribution of two systems of centrifugal neurons innervating the soma clusters of the olfactory midbrain across decapod crustaceans, brains of the following nine species comprising most infraorders were immunostained with antibodies against dopamine and the neuropeptides substance P and FMRFamide: Macrobrachium rosenbergii, Homarus americanus, Cherax destructor, Orconectes limosus, Procambarus clarkii, Astacus leptodactylus, Carcinus maenas, Eriocheir sinensis and Pagurus bernhardus. One system consisting of several neurons with dopamine-like immunoreactivity that originate in the eyestalk ganglia was present in the four crayfish but not in any other species. These neurons project mainly into the lateral soma clusters (cluster 10) comprising the somata of ascending olfactory projection neurons and innervate very sparsely the medial soma clusters (clusters 9 and 11) containing the somata of local interneurons. In the innervation pattern of the lateral cluster, the dopamine-immunoreactive neurons showed large species-specific differences. The other system comprises a pair of giant neurons with substance P-like immunoreactivity. These neurons have somata in the median protocerebrum of the central brain and major projections into the lateral clusters and the core of the olfactory lobes, the neuropils that are the first synaptic relay in the central olfactory pathway of decapods; minor arborizations are present in the medial clusters. The system of substance P-immunoreactive giant neurons was present and of great morphological similarity in all studied species. Only in one species, the shrimp Macrobrachium rosenbergii, evidence for co-localization of FMRFamide-like with substance P-like immunoreactivity in these neurons was obtained. These and previously collected data indicate that the centrifugal neurons with dopamine-like immunoreactivity may be associated with the presence of an accessory lobe, a second-order neuropil that receives input from the olfactory lobe and only occurs in spiny lobsters, clawed lobsters and crayfish. The pair of centrifugal giant neurons with substance P-like immunoreactivity, on the other hand, appears to be a constitutive component of the decapod crustacean brain that most likely is functionally associated with the olfactory lobe. Both systems apparently exert modulatory functions on olfactory information processing by preferentially targeting the somata of the projection neurons. Thus, in the olfactory projection neurons, the somata seem to be more directly involved in information processing than in most other neurons of the arthropod CNS.
Schmidt, M. (1997). Distribution of presumptive chemosensory afferents with FMRFamide- or substance P-like immunoreactivity in decapod crustaceans. Brain Res 746, 71-84.
In five species of decapod crustaceans--Cherax destructor (crayfish), Carcinus maenas (crab), Homarus americanus (clawed lobster), Eriocheir sinensis (crab), Macrobrachium rosenbergii (shrimp)--immunocytochemical stainings revealed the presence of sensory afferents with FMRFamide- like immunoreactivity in the central nervous system. These afferents were extremely thin, very numerous, and innervated all sensory neuropils except the optic and olfactory lobes. In their target neuropils they gave rise to condensed net- or ball-like terminal structures. Only in Homarus americanus but not in any other studied species immunocytochemistry revealed a separate, non-overlapping class of sensory afferents with substance P-like immunoreactivity. Also the afferents with substance P-like immunoreactivity were very thin and numerous, innervated all sensory neuropils except optic and olfactory lobes, and gave rise to condensed terminal structures. From their morphological characteristics it can be concluded that likely both classes of afferents are chemosensory. The substance P-like immunoreactivity suggests a link with the nociceptor afferents of vertebrates, with which both classes of afferents share several other morphological features.
Schneider, H., Trimmer, B. A., Rapus, J., Eckert, M., Valentine, D. E., and Kravitz, E. A. (1993). Mapping of octopamine-immunoreactive neurons in the central nervous system of the lobster. J Comp Neurol 329, 129-42.
It has been suggested that serotonin and octopamine serve important roles in behavioral regulation in lobsters. In this paper the locations of octopamine-immunoreactive neurons were mapped in wholemount preparations of the ventral nerve cord of 4th stage lobster (Homarus americanus) larvae. Approximately 86 neurons were found, distributed as follows: brain, 12; circumesophageal ganglia, 2; subesophageal ganglion, 38; thoracic ganglia, 6 each; and 4th and 5th abdominal ganglia, 2 each. All the octopamine-immunoreactive neurons are paired and located along the midline. Of the 86 neurons, 28 were identified as neurosecretory, and 26 as intersegmental ascending thoracic, ascending abdominal, or descending interneurons. The neurosecretory system is arranged segmentally and located entirely within the thoracic and subesophageal neuromeres with extensive terminal fields of endings along 2nd thoracic and subesophageal nerve roots. This set of neurons shares the features of central and peripheral endings with 2 pairs of large serotonin-containing neurosecretory neurons found in the fifth thoracic and first abdominal ganglia. The intersegmental neurons include: (1) two cells in the brain and 2 pairs of cells in the 3rd and 4th neuromeres of the subesophageal ganglion, which project to the 6th abdominal ganglion; (2) a segmentally organized group of ascending interneurons found in the subesophageal and in all thoracic ganglia; and (3) pairs of ascending interneurons found in the 4th and 5th ganglia in the abdominal nerve cord. By means of a biochemical assay, the cell bodies of octopamine-immunoreactive neurosecretory cells in the thoracic segment of the nerve cord were found to contain 40-100 fmol of octopamine, while control neurons had none.
Schneider, H., Budhiraja, P., Walter, I., Beltz, B. S., Peckol, E., and Kravitz, E. A. (1996). Developmental expression of the octopamine phenotype in lobsters, Homarus americanus. J Comp Neurol 371, 3-14.
We have used immunocytochemical methods to examine the sequence of appearance of octopamine-immunoreactive neurons during development, and to try to correlate that appearance with the emergence of behavioral or physiological capabilities. The first octopamine neurons express their transmitter phenotype at approximately 43% of embryonic development. The last cells show immunostaining at the 3rd larval stage. In the wild, therefore, immunoreactivity in cells appears over a 9-12 month period. In contrast, serotonin-immunoreactive neurons stain early in embryonic development and the last serotonin-immunoreactive cells appear at about the same time the first octopamine-immunoreactive neurons show staining. The pattern of appearance of octopamine- immunoreactive cells is cell type-specific. A pair of brain cells and the descending interneurons stain first. Additional brain cell staining is seen throughout embryonic development. The ascending interneurons appear next, and a general anterior-posterior gradient typifies their emergence over a relatively short portion of embryonic life (E 48-62%). The neurosecretory cell staining appears last, is segment-specific, begins at about 62% development, and continues to the 3rd larval stage. The emergence of immunostaining for amine neurotransmitters within groups of identified neurons at precise times in development may specify possible functional units. With at least one group of cells, this possibility seems plausible: the three pairs of claw octopamine neurosecretory cells show immunostaining as a unit.
Scholz, N. L., Chang, E. S., Graubard, K., and Truman, J. W. (1998). The NO/cGMP pathway and the development of neural networks in postembryonic lobsters. Journal of Neurobiology 34, 208-226.
The nitric oxide/cyclic 3',5'-guanosine monophosphate (NO/cGMP) signaling pathway has been implicated in certain forms of developmental and adult neuronal plasticity. Here we use wholemount immunocytochemistry to identify components of this pathway in the nervous system of postembryonic lobsters as they develop through metamorphosis. We find that the synthetic enzyme for NO (nitric oxide synthase, or NOS) and the receptor for this transmitter (NO-sensitive soluble guanylate cyclase) are broadly distributed in the central nervous system (CNS) at hatching. In the brain, NOS immunoreactivity is intensified during glomerular development in the olfactory and accessory lobes. Whereas only a few neurons express NOS in the CNS, many more neurons synthesize cGMP in the presence of NO. NO- sensitive guanylate cyclase activity is a stable feature of some cells, while in others it is regulated during development. In the stomatogastric nervous system, a subset of neurons become responsive to NO at metamorphosis, a time when larval networks are reorganized into adult motor circuits. cGMP accumulation was occasionally detected in the nucleus of many cells in the CNS, which suggests that cGMP may have a role in transcription. Based on these findings, we conclude that the NO/cGMP signaling pathway may participate in the development of the lobster nervous system. Furthermore, NO may serve as a modulatory neurotransmitter for diverse neurons throughout the CNS. (C) 1998 John Wiley & Sons, inc.
Schreiner, B., Staaland, D. H., and Johansson, A. S. (1969). Functional significance of neurosecretory cells in the last abdominal ganglion of the lobster, Homarus vulgaris L. Gen Comp Endocrinol 13, 399-402.
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Schwarz, T. L., Lee, G. M., Siwicki, K. K., Standaert, D. G., and Kravitz, E. A. (1984). Proctolin in the lobster: the distribution, release, and chemical characterization of a likely neurohormone. J Neurosci 4, 1300-11.
A radioimmunoassay, immunohistochemical techniques, and high pressure liquid chromatography (HPLC) methods have been developed for the study of the pentapeptide proctolin in the lobster Homarus americanus. Proctolin-like immunoreactivity is present in nearly every portion of the lobster nervous system; immunoreactivity is found in the brain, in each of the ganglia and connectives of the ventral nerve cord, and in many of the nerve roots that emerge from the cord. The greatest amounts are found in the pericardial organs, which are well known neurosecretory structures, and these structures have been selected for more detailed study. The immunoreactive material in the pericardial organs appears to be authentic proctolin. This material co-migrates with synthetic proctolin in two HPLC systems. Furthermore, a peptide that is purified from pericardial organs by HPLC is indistinguishable from synthetic proctolin in high resolution fast atom bombardment mass spectrometry. Cytochemistry reveals that the surface of the pericardial organs is densely covered with immunoreactive varicosities. No cell bodies that stain for proctolin are found in the pericardial organs, and the cells that give rise to the varicosities have not yet been located. The nerve endings in pericardial organs are capable of releasing proctolin-like material when depolarized in the presence of Ca++. These findings suggest that proctolin is a neurohormone in the lobster.
Sefiani, M., Le Caer, J. P., and Soyez, D. (1996). Characterization of hyperglycemic and molt-inhibiting activity from sinus glands of the penaeid shrimp Penaeus vannamei. Gen Comp Endocrinol 103, 41-53.
To design a homologous bioassay for the molt-inhibiting hormone and the crustacean hyperglycemic hormone of the shrimp Penaeus vannamei, the effect of sinus gland homogenate (SGh), in vitro, on ecdysteroid production by Y-organs (YOs), and the effect of the injection of SGh, in vivo, on the glycemia of shrimps have been investigated. Addition of SGh to incubation medium of shrimp YOs dose dependently reduced, within a few hours, ecdysteroid release into the medium. Moreover, inhibition by SGh decreases drastically in YOs from animals in late premolt stages, when there is maximal ecdysteroid production. Injection of SGh into shrimps evokes a hyperglycemic response maximal after 2 hr. Immunoadsorption of SGh with an anti-Homarus americanus cHHA antiserum inhibited both biological activities of the homogenate. After fractionation of acidic sinus gland extract by RP-HPLC, the maximal response in both bioassays was associated with the major UV absorbent peak, which was also the major immunoreactive peak when tested by ELISA with the anti-lobster cHHA. After a further purification step, the molecular mass of the bioactive and immunoreactive peptide was found to be 8627 +/- 0.3 Da by electrospray ionization mass spectrometry. The amino acid sequence of the first 38 residues of this peptide was established by gas-phase microsequencing. This sequence shows 55% homology with the first 38 residues of the lobster cHHA.
Shalev, A., Goldenberg, P. Z., and Huebner, E. (1980). Evidence for an H-Y crossreactive antigen in invertebrates. Differentiation 16, 77-80.
A sex specific antigen which crossreacts with the mammalian H-Y antigen has been identified on the cell surface of hemocytes from the lobster (Homarus americanus) and the gonadal cells of three insect species. The hemocytes from the male lobster, the testicular cells from the male beetle (P. cornutus), and the ovarian cells from two Orthopteran species (L. maderae and D. punctata) specifically absorbed H-Y antibodies. The specificity of H-Y antibody absorptions by cells from only one sex, suggest that an ancestral H-Y-like antigen may be present in invertebrates which could be engaged in sexual (cellular) recognition events.
Sheehy, M. R. J., Bannister, R. C. A., Wickins, J. F., and Shelton, P. M. J. (1999). New perspectives on the growth and longevity of the European lobster (Homarus gammarus). Canadian Journal of Fisheries and Aquatic Sciences 56, 1904-1915.
The natural rate of lipofuscin accumulation in an eyestalk ganglion was determined from microtagged European lobsters, Homarus gammarus, of known age, recaptured from the Yorkshire fishery (United Kingdom). This calibration, in combination with supporting data from shorter-lived astacideans (freshwater crayfish), was used to age wild lobsters from the fishery. A unique perspective of age-at-size in a clawed-lobster population was obtained, which circumvented some difficulties associated with conventional methods for estimating generalized growth and natural mortality. The exceptional ages attained by some of the largest lobsters (males: average 31 years, maximum 42 +/- 5 years; females: average 54 years, maximum 72 +/- 9 years) are explained by ageing theory, indicate natural mortality rates, M, of 0.15 and 0.08 for males and females, respectively, and point to the existence of an offshore refuge. Age-at-size is highly variable: at least seven year-classes enter the fishery at 85 mm carapace length. This limits resolution of annual cohorts in size compositions, complicates development of recruitment indices, and may explain past size composition stability. The new age-length data suggest potential selective fishing impacts and past early recruitment variations. The study highlights the need for age data in order to obtain accurate crustacean stock assessments.
Sherman, R. G., and Atwood, H. L. (1971). Structure and neuromuscular physiology of a newly discovered muscle in the walking legs of the lobster Homarus americanus. J Exp Zool 176, 461-74.
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Shieh, H. S. (1969). The biosynthesis of phospholipids in the lobster, Homarus americanus. Comp Biochem Physiol 30, 679-84.
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Shih, T. W., Suzuki, Y., Nagasawa, H., and Aida, K. (1998). Immunohistochemical identification of hyperglycemic hormone- and molt-inhibiting hormone-producing cells in the eyestalk of the kuruma prawn, Penaeus japonicus. Zoological Science 15, 389-397.
This study deals with the localization of crustacean hyperglycemic hormone (CHH, Pej-SGP-III) and molt-inhibiting hormone (MIH, Pej-SGP-IV) in the eyestalk of the kuruma prawn Penaeus japonicus using immunohistochemistry. High-titer and highly specific antisera were raised in rabbits against synthetic Pej-SGP-III C-terminal peptide (Glu-Glu-His-Met-Ala- Ala-Met-Gln-Thr-Val-NH2) and Pej-SGP-IV C-terminal peptide (Val-Trp-Ile-Ser-Ile-Leu-Asn-Ala-Gly-Gln-OH), both of which were conjugated with bovine serum albumin by a cross linker. Eyestalks were removed from mature male prawns at the intermolt stage of the molting cycle and fixed in Bouin's solution. Serial sections stained immunohistochemically showed that neurosecretory cells of Pej-SGP-III and Pej-SGP-IV were located in the same cluster of the medulla terminalis ganglionic X- organ (MTGX), and that three kinds of neurosecretory cells, which were stained with anti-Pej-SGP-III antiserum and/or anti- Pej-SGP-IV antiserum were present. The number of neurosecretory cells which stained with both antisera was much fewer than that of neurosecretory cells which stained with one of the antisera only. The axon and axon terminals in the sinus gland were also stained and the staining density of the sinus gland was always deeper than that of the neurosecretory cells.
Shimada, R., Ushio, H., and Yamanaka, H. (1998). Changes in content of extractive components in the tail muscle of three species of lobsters during storage. Fisheries Science 64, 979-984.
Post-mortem changes in content of ATP and its related compounds, free amino acids, and polyamines were investigated in the tail muscle of Japanese spiny lobster Panulirus japonicus, rock lobster Jasus lalandii from South Africa, and American lobster Homarus americanus from Canada during storage at 0, 5, and 10 degrees C. Initial ATP level in the muscle of Japanese spiny lobster was higher than other species and the decreasing rate was the slowest. During storage, AMP and IMP accumulated to a similar extent in the muscle of Japanese spiny lobster, while only IMP accumulated in the muscle of American lobster. In the muscle of rock lobster, neither AMP nor IMP accumulated and inosine increased rapidly. Taurine, asparagine, glutamine, proline, glycine, and arginine were dominant in every lobster, and no polyamine was detected in the early stage of storage. With degradation of arginine, ornithine increased in the muscle of rock lobster, while both ornithine and putrescine increased to about the half of the initial arginine level in the muscle of American lobster. Arginine remained at a higher level, and the other two compounds did not increase in the muscle of Japanese spiny lobster.
Siemankowski, R. F., and Zobel, C. R. (1976). Comparative studies on the structure and aggregative properties of the myosin molecule. I. The structure of the lobster myosin molecule. J Mechanochem Cell Motil 3, 171-84.
Myosin purified from the abdominal flexor muscle of the lobster, Homarus americanus, has a number average length of 1559 +/- 218 A, a rod like tail 1335 A long and a globular head 225 X 45 A as determined from electron microscopic observations on platinum shadowed preparations. The mass of the molecule was determined to be ca. 486,000 daltons from high speed equilibrium centrifugation studies at neutral and alkaline pH, and by SDS-acrylamide gel electrophoresis. Both sedimentation equilibrium centrifuge studies at alkaline pH and SDS- acrylamide gel electrophoresis experiments, indicate that the molecule contains a heavy chain core (two polypeptide chains weighing ca. 210,000 daltons each) and ca. four light chains of two weight classes (ca. 16,000 and 20,000 daltons). The amino acid composition of the myosin was determined. The specific activities of the Mg2+ -activated, K+/EDTA-activated, and Ca2+ -activated ATPases of the myosin were determined. Kinetic analysis of the digestion of lobster myosin with trypsin suggests that lobster myosin contains three classes of lysine and arginine residues; slowly split (k = 2.07 +/- 0.31 X 10(-2) moles/min2), rapidly split (k = 11.0 +/- 1.83 X 10(-2) moles/min2) and trypsin insensitive. There are 187 +/- 22 slowly split residues, 280 +/- 35 rapidly split residues, and 144 +/- 41 trypsin insensitive bonds per molecule. Comparison of these molecular parameters with those for the vertebrate skeletal muscle myosin indicates that the two myosins are similar in terms of mass, shape and overall polypeptide chain composition but may be considerably different in terms of local polypeptide chain conformation or composition.
Sikerwar, S. S., Downing, K. H., and Glaeser, R. M. (1991). Three-dimensional structure of an invertebrate intercellular communicating junction. J Struct Biol 106, 255-63.
Gap junctions containing extensive, highly ordered crystalline arrays of hexagonally packed connexons have been isolated from the hepatopancreas of the arthropod, Homarus americanus (American lobster). The structure of such junctions has been studied to a resolution of approximately 25 A in three dimensions by electron microscopy of negatively stained specimens. The structure, which has the crystallographic symmetry of the two-sided plane group p6, reveals the connexon as an annular oligomer which projects approximately 30-45 A from the cytoplasmic surface. The stain-filled channel structure appears to be approximately 40-45 A wide in the extracellular region. Projection images of glucose-embedded specimens extend to a resolution of 10 A, and show a strong contrast from the connexon subunits. Overall the structure is quite similar to that of rat liver junctions, except that less stain is seen in the aqueous region of the gap and more surrounding the protrusions of the protein into the cytoplasm.
Simmers, J., and Moulins, M. (1988). Nonlinear interneuronal properties underlie integrative flexibility in a lobster disynaptic sensorimotor pathway. J Neurophysiol 59, 757-77.
1. In the lobster Homarus, a single mechanoreceptor neuron (anterior gastric receptor, AGR) associated with muscle gm 1 of the gastric medial tooth has access to motoneurons (GM) innervating this muscle via an excitatory synaptic pathway involving two bilateral interneurons (commissural gastric, CG) (see 31). 2. Studies on in vitro preparations of the stomatogastric nervous system show that despite its apparent simplicity, this disynaptic pathway can express considerable flexibility in information processing, as evident by a wide variety of GM output responses to sensory input from AGR (Fig. 1). 3. This input/output flexibility does not rely on multiple synaptic pathways operating in parallel with the interneuron CG, since it is demonstrated that AGR has access to GM only via CG (Fig. 2). 4. Short AGR impulse trains at different spike frequencies can give rise to similarly brief excitation of GM, or prolonged motoneuron responses. Moreover, graded increases in AGR discharge frequency can lead to a sudden increase in the intensity of GM responsiveness that otherwise grades linearly with receptor firing. Such step changes in gain (both in duration and magnitude) are due to synaptic triggering of regenerative "plateau" depolarizations in CG (Figs. 3 and 4). 5. Sustained tonic discharge in AGR can induce cyclic bursting activity in previously nonrhythmic GM neurons. Furthermore, the frequency of motoneuron bursts increases with the frequency of AGR tonic firing. Such changes in pattern are ascribed to synaptic triggering and modification of regenerative "oscillatory" depolarizations in CG (Fig. 5). 6. Higher levels of AGR firing can result either in strong activation of GM motoneurons or in complete inactivation of GM. This switch in sign of the motor response is dependent on base-line levels of activity in the receptor and is due to the capability of CG to fire action potentials only within a window of membrane potential (Figs. 6-8). The functional outcome of this cellular property of CG is that positive feedback from AGR to GM can be switched to negative feedback via the same excitatory synaptic pathway (Fig. 9). 7. We conclude that flexibility in sensorimotor integration can be an inbuilt feature even of hard-wired neuronal pathways; in the present case, changes in input/output relationships reside with intrinsic properties of an intercalated interneuron (Fig. 10).
Simmers, J., and Moulins, M. (1988). A disynaptic sensorimotor pathway in the lobster stomatogastric system. J Neurophysiol 59, 740-56.
1. In the lobster Homarus, muscle gm 1 that causes protraction of the medial tooth of the gastric mill system is innervated via a dorsal branch of the anterior gastric nerve by motoneurons (GM) arising in the stomatogastric ganglion (STG) (Fig. 1). 2. A ventral branch of the anterior gastric nerve (VAGN) contains a single unit that is mechanosensitive, responds to gentle pressure on the stomach wall in the vicinity of gm 1, and evokes reflex activation of GM motoneurons (Fig. 2). 3. This mechanoreceptor neuron (called anterior gastric receptor, AGR) has been identified morphologically (Fig. 3) and electrophysiologically (Figs. 4 and 5). The bipolar cell body is located in the dorsal ventricular nerve immediately posterior to the STG. It sends out long peripheral processes in the left and right VAGNs to ramify bilaterally in the epidermis of the stomach wall underlying muscle gm 1. The axon of the AGR runs anteriorly through the STG and projects to the left and right commissural ganglia (CoGs) via the stomatogastric (STN) and inferior esophageal nerves. 4. AGR activation of GM motoneurons disappears after cutting the STN, indicating that the reflex is mediated by an axonal pathway involving rostral ganglia (Fig. 6). 5. Electrophysiological (Fig. 7) and morphological (Fig. 8) methods were used to identify an interneuron (commissural gastric neuron, CG) located in each CoG and intercalated between AGR and GM. Axons of the two CGs project to the STG via the superior esophageal nerves and the STN. 6. Simultaneous intracellular recordings from the three cell types demonstrate that AGR excites CG, which in turn excites GM; in each case excitatory postsynaptic potentials follow presynaptic impulses one for one and at constant latency (Fig. 9). Raising the threshold for spiking with saline containing high divalent cation concentrations further indicates that both excitatory connections are monosynaptic and confirms that AGR does not directly excite GM motoneurons (Fig. 10). 7. The input/output properties of AGR in this disynaptic excitatory pathway (Fig. 11) are discussed as also are the functional implications of such a long-loop pathway for sensorimotor integration.
Sithigorngul, P., Saraithongkum, W., Jaideechoey, S., Longyant, S., and Sithigorngul, W. (1998). Novel FMRFamide-like neuropeptides from the eyestalk of the giant freshwater prawn Macrobrachium rosenbergii. Comparative Biochemistry and Physiology B-Biochemistry & Molecular Biology 120, 587-595.
Isolation of the FMRFamide-like neuropeptides (FLPs) from the eyestalk of the giant freshwater prawn Macrobrachium rosenbergii was performed using 5000 ground eyestalks extracted in methanol/acetic acid/water (90:1:9). After the extract was partially purified using C18 cartridges, it was further purified by eight steps of RP-HPLC using four kinds of columns: C18, C8, cyano and phenyl, and three solvent systems: acetonitrile (ACN)/trifluoroacetic acid, ACN/heptafluoroacetic acid and ACN/triethylammonium acetate. Dot-ELISA, using a mixture of two monoclonal antibodies, FM-23 (made against FMRFamide) and AF1-62 (made against KNEFIRFamide), was used to monitor FLPs in the fractions during the purification processes. Two subfamilies of five FLPs were obtained from the first six fractions of the first step of purification by RP- HPLC; four of them are new sequences. Three FLPs, DRNFLRFamide, ADKNFLRFamide and NYDKNFLRFamide share five to seven common C- terminus residues with those found in the pericardial organs of Homarus americanus, Callinectes sapidus and Procambarus clarkii. The other two FLPs, APALRLRFamide and DRTPALRLRFamide, share six common residues at the C-terminus with those found in Limulus polyphemus and Periplaneta americana. These findings suggest that more than one transcript might be responsible for encoding FLPs in M. rosenbergii. (C) 1998 Elsevier Science Inc. All rights reserved.
Sithigorngul, P., Panchan, N., Vilaivan, T., Sithigorngul, W., and Petsom, A. (1999). Immunochemical analysis and immunocytochemical localization of crustacean hyperglycemic hormone from the eyestalk of Macrobrachium rosenbergii. Comparative Biochemistry and Physiology B-Biochemistry & Molecular Biology 124, 73-80.
Heptapeptide (YANAVQV-NH2 = T -) and octapeptide (YANAVQTV-NH2 = T +), the putative C-terminus of crustacean hyperglycemic hormone (CHH) from the eyestalk of the giant freshwater prawn Macrobrachium rosenbergii, was synthesized by solid phase peptide synthesis and conjugated to bovine serum albumin, then used for immunization in swiss mice. Specificity of the antisera against both peptides was determined by indirect immunoperoxidase ELISA. The best response of antiserum against each peptide was used to determine the presence of the natural CHH in the eyestalk extract after separation by one step of RP- HPLC using dot-ELISA. The peptide immunoreactive substances were found in fraction 30 using anti-T - antiserum and in fraction 38 using anti-T + antiserum. However, the CHH activity was found only in fractions 37-39. Immunocytochemical localization of peptide immunoreactive substances in the eyestalk of M. rosenbergii using the anti-T - antiserum did not show any specific staining. In contrast, the anti-T + antiserum revealed specific staining on a group of 24 +/- 5 neurons in medulla terminalis ganglionic x-organ and their processes through the sinus gland. Similar results were also obtained using the eyestalk of another species, the giant tiger prawn Penaeus monodon, in which 34 +/- 4 neuronal cells were recognized. These results strongly indicate that the anti-T + antibody can bind to the natural CHH while the anti-T - antibody can not; therefore, this isoform of CHH in M. rosenbergii should consist of 72 residues and threonine is predicted to be present at position 71. (C) 1999 Elsevier Science Inc. All rights reserved.
Sithigorngul, W., Jaideechoey, S., Saraithongkum, W., Longyant, S., and Sithigorngul, P. (1999). Purification and characterization of an isoform of crustacean hyperglycemic hormone from the eyestalk of Macrobrachium rosenbergii. Journal of Experimental Zoology 284, 217-224.
Isolation of the crustacean hyperglycemic hormone (CHH) from the eyestalk of the giant freshwater prawn Macrobrachium rosenbergii was performed using 5,000 ground eyestalks extracted in methanol-acetic acid-water (90:1:9). After the extract was partially purified using C18 cartridges, it was further purified by eight steps of RP-HPLC using four kinds of columns: C18, C8, cyano and phenyl, and three solvent systems: acetonitrile (ACN)/trifluoroacetic acid, ACN/heptafluoroacetic acid and ACN/triethylammonium acetate. The bioassay of CHH during purification was done by injection of eluate fractions into eyestalk-ablated prawns and determination of the ability of the fractions to elevate glucose in the haemolymph. A complete amino acid sequence analysis was performed on one isoform of CHH (Mar-CHH-1), consisting of 71 residues. The sequence of Mar-CHH-1 shows considerable similarity (45-68%) to CHHs reported in other crustaceans. It is expected that there might be more than one isoform of CHH in M. rosenbergii. J. Exp. Zool. 284:217-224, 1999. (C) 1999 Wiley-Liss, Inc.
Siwicki, K. K., Beltz, B. S., Schwarz, T. L., and Kravitz, E. A. (1985). Proctolin in the lobster nervous system. Peptides 6, 393-402.
The pentapeptide proctolin (Arg-Tyr-Leu-Pro-Thr) is present in high concentrations in neurosecretory organs of the lobster, Homarus americanus. The central nervous system contains ca. 1400 proctolin- immunoreactive neurons, which appear to serve a variety of different functions. Some of these neurons have been specifically identified and analyzed biochemically to determine which classical neurotransmitters coexist with the peptide. These include: serotonin-proctolin cell pairs in the fifth thoracic and first abdominal ganglia; a large dopamine- proctolin neuron in the circumesophageal ganglion; and cholinergic- proctolin sensory neurons which innervate a mechanoreceptor in the scaphognathite. With these identified neurons we have begun to investigate the physiological actions of proctolin, the interactions between cotransmitters, and the development of multiple transmitter phenotypes in individual neurons.
Siwicki, K. K., and Bishop, C. A. (1986). Mapping of proctolinlike immunoreactivity in the nervous systems of lobster and crayfish. J Comp Neurol 243, 435-53.
Whole-mount immunocytochemical techniques have been used to map candidate proctolin-containing cells in the central nervous systems of the lobster, Homarus americanus, and the crayfish, Procambarus clarkii. Proctolinlike immunoreactivity was detected in cell bodies and neuropil regions in all central ganglia, and immunoreactive axons were detected in most interganglionic connectives and nerve roots. Cell body staining was confined to fewer than 2% of all cells. Immunoreactive neurons include motoneurons, sensory neurons, neurosecretory cells, and interneurons. Colocalization of the proctolinlike antigen with other neurotransmitters was indicated in a number of cases. Many aspects of the distribution of immunoreactivity were similar in lobster and crayfish; however, staining differences were detected in a number of identified neurons and neural groups, including neurons that innervate the pericardial organs and hindgut motoneurons. Further studies of such neurons might provide interesting clues about the physiological functions of proctolin and the evolution of peptide transmission.
Siwicki, K. K., Beltz, B. S., and Kravitz, E. A. (1987). Proctolin in identified serotonergic, dopaminergic, and cholinergic neurons in the lobster, Homarus americanus. J Neurosci 7, 522-32.
In order to explore the functions of the peptide proctolin in the lobster nervous system, 3 classes of neurons showing proctolin-like immunocytochemical staining were selected for study. These neurons were identified on the basis of physiological and/or morphological criteria, isolated by dissections, and analyzed with biochemical methods to determine whether they contained authentic proctolin and which classical neurotransmitters coexisted with the peptide. Pairs of large proctolin-immunoreactive neurons in fifth thoracic and first abdominal ganglia were identified as serotonin-immunoreactive neurons (Beltz and Kravitz, 1983, 1987) by staining serial sections of the ganglia alternately with the 2 antisera. Physiologically identified cells, dissected from the ganglia and analyzed with high-performance liquid chromatography (HPLC), contained approximately 20 microM proctolin and 0.5 mM serotonin. A large proctolin-immunoreactive neuron in the circumesophageal ganglion was identified as the lobster homolog of a dopaminergic neurosecretory cell found in other crustaceans (Cooke and Goldstone, 1970). The large lobster cell stained with antityrosine hydroxylase antiserum, and synthesized 3H-dopamine from 3H-tyrosine. Dissected cell bodies, analyzed by HPLC, contained approximately 25 microM proctolin. Proctolin-immunoreactive sensory neurons were identified as large stained fibers that terminated in sensory dendrites of the oval organ mechanoreceptor in the scaphognathite (Pasztor, 1979; Pasztor and Bush, 1982). The largest sensory fiber was isolated for biochemical studies. It synthesized 3H-acetylcholine from 3H-choline and, by HPLC analysis, was found to contain approximately 3 microM proctolin. Thus, proctolin coexists with different conventional transmitters in several classes of identified lobster neurons. Investigations of the actions of proctolin in these different contexts should contribute to a more complete understanding of the diverse functions of neuropeptides and their roles as cotransmitters.
Skajaa, K., Ferno, A., Lokkeborg, S., and Haugland, E. K. (1998). Basic movement pattern and chemo-oriented search towards baited pots in edible crab (Cancer pagurus L.). Hydrobiologia 372, 143-153.
The basic (natural) movement pattern and gear-induced behaviour of female edible crab Cancer pagurus L. were studied by means of a stationary positioning system. Nine crabs were tagged with ultrasonic transmitters and their positions were monitored approximately every third minute for 9-24 days. Because the crabs sometimes hid, the signals were often received improperly, resulting in inaccurate position fixes, and a computer program to distinguish between movement and inactivity was developed. Edible crabs showed a nocturnal activity cycle. During the day crabs were in hiding as indicated by less accurate position fixes. There were variations in activity levels both between and within individuals. Three crabs hardly moved at all during the study, while the others were active during some, or all nights. The crabs did not return to the same place after movement, but stayed close to the hydrophone triangle (290 x 350 x 175 m) throughout the study. The activity and movement patterns are discussed in relation to optimal foraging behaviour and predator avoidance. Six baited pots were set in the area on seven nights. Four of the crabs located baited pots during the study. Three crabs located pots more than once, resulting in a total of nine localisations. Three of the tagged crabs were caught. The localisations of baited pots were divided into four categories on the basis of the current direction at the start of the localisation and whether the crab was caught or not, in order to suggest the probability of the localisation being chemically stimulated. At least six of the localisations seemed to be induced by chemical attraction to the bait. Pots were always located during night at the time of high activity. The searching distances ranged from 12 to 48 m. Speed of movement during searching was higher than speed during basic movement.
Skiebe, P. (1999). Allatostatin-like immunoreactivity in the stomatogastric nervous system and the pericardial organs of the crab Cancer pagurus, the lobster Homarus americanus, and the crayfish Cherax destructor and Procambarus clarkii. Journal of Comparative Neurology 403, 85-105.
The distribution of allatostatin (AST)-like immunoreactivity was studied in the stomatogastric nervous system (STNS) and the neurosecretory pericardial organs (PO) of four decapod crustacean species by using wholemount immunocytochemical techniques and confocal microscopy. AST-like immunoreactivity was found within the STNS of all four species; its distribution in each was unique. In all four species, AST-like immunoreactivity was present in the paired commissural ganglia (CoG), in the esophageal ganglion (OG), in the stomatogastric ganglion (STG), and in their connecting nerves. Within the CoGs, numerous cell bodies and neuropil were stained. In the OG, two cell bodies were immunoreactive, although their branching pattern varies between species. In the STG of C. pagurus and H. americanus, neuropil was stained extensively, but no labeled cell bodies were found. Surprisingly, in C. destructor and P. clarkii, cell bodies were stained in the STG, one brightly stained cell body in both species and an additional two to five weakly stained cell bodies in P. clarkii. In all four species, stained gastropyloric receptor cells were present. In contrast to the variable staining within the STNS, all four species have a similar pattern of AST-like immunoreactivity within the PO. Only in C. destructor, AST- immunoreactive varicosities occur on the surface of the circumesophageal connectives and on the postesophageal commissure and suggest another neurohaemal source for AST-Like peptides in this species. The pattern of this staining suggests that AST-like peptides are likely utilized as both neurohormones and as neuromodulators in the STNS of decapod crustacea. J. Comp. Neurol. 403:85-105, 1999. (C) 1999 Wiley- Liss, Inc.
Smith, D. S., and Anderson, M. E. (1972). The disposition of membrane systems in cardiac muscle of a lobster, Homarus americanus. Tissue Cell 4, 629-45.
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Smith, I. P., Collins, K. J., and Jensen, A. C. (1998). Movement and activity patterns of the European lobster, Homarus gammarus, revealed by electromagnetic telemetry. Marine Biology 132, 611-623.
European lobsters, Homarus gammarus (L.), were tracked on an artificial reef in Poole Bay on the south coast of England using an electromagnetic telemetry system which monitored movements between reef units and recorded body movements (pitching and rolling) detected with a tilt switch incorporated into the transmitting tag. Several environmental variables (water temperature, light, hydrostatic pressure, current velocity and direction) were recorded simultaneously by the telemetry system, which was self-contained on the seabed. Movements between units of the artificial reef (excursions outside shelter) were predominantly nocturnal, peaking 1.5 to 3 h after sunset and returning to low levels shortly before dawn. A marked decline in the number of inter-reef unit movements from late summer to winter was related to decreasing water temperature rather than to daytime light level, wave height or tidal range. Activity indicated by the tilt switch was also greater at night, but declined gradually fr-om a peak early in the night to a minimum at around midday, on average, implying a degree of activity within reef units during daylight. As with movements between reef units; activity declined seasonally with decreasing water temperature; in addition, the diel pattern of activity disappeared in winter.
Smith, I. P., Collins, K. J., and Jensen, A. C. (1998). Electromagnetic telemetry of lobster (Homarus gammarus (L.)) movements and activity: preliminary results. Hydrobiologia 372, 133-141.
Individual European lobsters were tracked on an artificial reef using an electromagnetic telemetry system, which detected movements between reef units and also recorded body movements (pitching and rolling) indicated by a tilt switch incorporated into the transmitting tag. Several environmental variables were recorded simultaneously by the telemetry system, which was self-contained on the seabed. To date, 26 lobsters (14 female, 12 male) have been tagged, up to seven have been monitored simultaneously and four individuals have been tracked for over 6 months. Movements between units of the artificial reef (over open seabed away from shelter) were predominantly nocturnal, although daytime movements occurred during periods of low light levels associated with increased turbidity resulting from wave action. A marked decline in the number of inter-reef movements from late summer to winter was most closely related to decreasing water temperature. Activity indicated by the tilt switch was greater at night for most lobsters, but there were moderate levels of activity during the day. As with inter-reef movements, activity declined as winter progressed and in addition the diel pattern diminished.
Smith, D. L., Knowles, J. F., and Winpenny, K. (1998). The accumulation, retention and distribution of Tc-95m in crab (Cancer pagurus L.) and lobster (Homarus gammarus L.). A comparative study. Journal of Environmental Radioactivity 40, 113-135.
The accumulation, retention and distribution of Tc-95m has been compared in lobsters and edible a abs kept under identical experimental conditions. The steady-state concentration factor (C-ss) for the uptake of Tc-95m from seawater was significantly greater for female crabs (C-ss = 17.9) than for males (C-ss =14.4), whereas in lobsters where was no such sex difference and the C-ss of 1161 was much greater than in cl nbs. The uptake of technetium from food (as indicated by whole body counts) was only moderately greater in lobsters than crabs. Retention of Tc-95m was similar for crabs and lobsters of both sexes but the clearance rate was greater after the nuclide had been taken up from seawater (t(b1/2) = 51 days) than from food (t(b1/2) = 108 days). In all crabs and most male lobsters Tc- 95m was predominantly in the hepatopancreas while in a few male and all female lobsters it was mainly in muscle. Lobster ovaries consistently contained more activity than testes but this difference was nor seen in crabs. In hepatopancreas cells of both species Tc-95m occur fed mainly in the cytosol and some initial steps were taken to determine the relationship between technetium and cytosol proteins. The results for crab and lobster are compared with those from previous studies on these and other crustacean species. The possible basis for the much higher concentrations of technetium in lobsters than crabs is discussed and further research suggested. Crown copyright (C) 1998 Published by Elsevier Science Ltd, All rights reserved.
Smith, I. P., Collins, K. J., and Jensen, A. C. (1999). Seasonal changes in the level and diel pattern of activity in the European lobster Homarus gammarus. Marine Ecology-Progress Series 186, 255-264.
European lobsters are large, mobile crustaceans of ecological and commercial significance. Until recently, the lack of a reliable technique for long-term, in situ monitoring of activity has hindered study of seasonal variation in activity and its determinants. Electromagnetic telemetry has been used to measure seasonal changes in locomotor activity and body movements of lobsters on an artificial reef in Poole Bay, southern England. Both measures of activity showed marked seasonal variation, related primarily to water temperature, with greatest activity in late summer and minimum values in winter. Subsidiary effects of water movement and seabed illumination were also indicated. Throughout the spring and summer, excursions outside shelter were almost exclusively nocturnal, with movement peaking in the early part of the night. Body movements followed a similar pattern, but with less abrupt changes, suggesting a degree of activity within shelters during the day. Diel timing of lobster activity appeared to be mainly governed exogenously by light level, since the length of the nocturnal active period and the timing of the activity peak varied seasonally with the times of sunset and sunrise, and there was a relative increase in diurnal activity during periods of low seabed light levels caused by increased turbidity. During low temperatures in mid to late winter, activity was low throughout the 24 h cycle. These findings suggest that there are Likely to be significant seasonal changes in the relationship between fishing effort and fishing mortality that need to be taken into account in lobster stock assessment.
Snyder, M. J., and Chang, E. S. (1991). Ecdysteroids in relation to the molt cycle of the American lobster, Homarus americanus. II. excretion of metabolites. Gen Comp Endocrinol 83, 118-31.
Ecdysteroid (Ecd) excretion patterns were followed during the molt cycle of adult male and female lobsters. Homarus americanus. Urine was the major route of Ecd elimination, amounting to greater than or equal to 96% of the excreted radioimmunoassay activity for all molt stages. The other identified route of Ecd elimination from the hemolymph was the feces, which accounted for the remaining 4% of the total Ecd excretion. High polarity metabolites (HP), including 20,26- dihydroxyecdysone (2026E) and 20-hydroxyecdysonoic acid (20EA), were the major types of Ecds found in the urine. Other urinary Ecd components included 20-hydroxyecdysone (20E), ecdysone (E), and ponasterone A (P). The major portion of urinary HP was composed of conjugates of 2026E, 20E, E, P, and other unidentified metabolites. The fecal Ecds were predominately HP and apolar metabolites. Apolar fecal Ecds were hydrolyzable to release 20EA, 2026E, 20E, E, P, and other metabolites. By means of intubation, [3H]E was placed directly into the cardiac stomach of lobsters. The gut pathway formed an apolar conjugate of [3H]E which was found exclusively in the feces. Lobsters are therefore capable of excreting ingested Ecds without absorption.
Snyder, M. J., and Chang, E. S. (1991). Ecdysteroids in relation to the molt cycle of the American lobster, Homarus americanus. I. Hemolymph titers and metabolites. Gen Comp Endocrinol 81, 133-45.
Hemolymph ecdysteroid (Ecd) titers were measured using radioimmunoassay (RIA) during the molt cycle of the American lobster, Homarus americanus. Individual animals showed small, transitory rises of Ecds which increased in magnitude with the onset of premolt and culminated in a large premolt peak at morphological stages D2(2)-D3(1). Male lobsters had significant postmolt peaks and late premolt titers that remained high until ecdysis. In females, postmolt peaks were absent and late premolt titers reached basal levels before ecdysis. At least seven different Ecd metabolites were identified by high-performance liquid chromatography-RIA analyses. High polarity products (HP) were the most abundant metabolites in virtually every molt stage. Titers of HP were significantly higher in males during late postmolt-early intermolt and in late premolt. Levels of 20-hydroxyecdysone (20E) were equivalent in both sexes and correlated with the morphological changes associated with premolt. Evidence was also obtained for the presence of ecdysone, ponasterone A, and other as yet unidentified metabolites. The pattern of Ecd metabolites in the hemolymph supports other data indicative of 20E as the major molting hormone. Metabolism of 20E is primarily toward more polar compounds, including conjugates.
Snyder, M. J., and Chang, E. S. (1992). Role of the midgut gland in metabolism and excretion of ecdysteroids by lobsters, Homarus americanus. Gen Comp Endocrinol 85, 286-96.
The chromatographic profile of ecdysteroids (Ecds) from the midgut gland (MG) of juvenile female lobsters, Homarus americanus, was examined using high-performance liquid chromatography (HPLC) and radioimmunoassay (RIA) over four stages of the molt cycle. Upon initial examination, highly polar Ecd conjugates appeared to be the principal metabolites found in all molt stages. HPLC fractions containing apolar Ecds initially exhibited low RIA activity. Upon hydrolysis with a Helix pomatia enzyme preparation and reanalysis, significant amounts of other Ecds were released. Amounts of apolar Ecd conjugates were estimated, at their highest levels, to be at least 50% of the total Ecds in MGs of molt stage D3 lobsters. Only the MG formed significant amounts of apolar Ecds upon in vitro culture with [3H]ecdysone ([3H]E). Epidermis and antennal gland significantly increased their rates of [3H]E metabolism in vitro between molt stages C4 and D1. This result further supports the idea that regulation of ecdysteroid metabolism, at least in selected tissues, may be important in the molt cycle regulation of hormone titers. Using gel filtration column chromatography and sucrose density gradient centrifugation analyses, evidence was found for association of apolar Ecds with a protein(s) from MG cytosol. The protein was estimated to have a molecular weight of 180,000-200,000 and specifically bound apolar Ecds.
Snyder, M. J. (1998). Identification of a new cytochrome P450 family, CYP45, from the lobster, Homarus americanus, and expression following hormone and xenobiotic exposures. Archives of Biochemistry and Biophysics 358, 271-276.
Anew cytochrome P450, the first member of the CYP45 family, was identified from the hepatopancreas of the American lobster, Homarus americanus. The lobster CYP45 shares significant sequence homologies to the vertebrate CYP3 and the invertebrate CYP6, CYP9, CYP28, and CYP30 families, perhaps indicating a common ancestor of these P450s. Of seven tissues examined, CYP45 was expressed only in the hepatopancreas, the crustacean equivalent of the vertebrate liver, pancreas, and intestine. Over the course of the lobster molt cycle, CYP45 expression mirrored the hemolymph titer of ecdysteroids, suggesting its potential involvement in molting hormone dynamics. This idea was strengthened further by ecdysteroid treatment of intermolt- stage lobsters during the lowest hemolymph titers and CYP45 expression levels. Significant elevations in hepatopancreas CYP45 mRNA levels were elicited by such injections over a 2- to 4-day interval. Similar experiments were performed by intubating juvenile lobsters with various xenobiotics. Induction of CYP45 expression occurred following phenobarbital and heptachlor administration, but not by beta-naphthoflavone. Hormonal and xenobiotic modulation of lobster CYP45 expression provides a potential pathway for endocrine disruption in lobsters. (C) 1998 Academic Press.
Snyder, M. F. (1999). Ribosomal proteins S27E, p2, and L37A from marine invertebrates. Marine Biotechnology 1, 184-190.
Single complementary DNAs encoding sequences for 40S ribosomal proteins related to S27E from the American lobster Homarus americanus and mussel Mytilus galloprovincialis were characterized. Single genes for ribosomal proteins L37A and P2 from the gumboot chiton Cryptochiton stellerii, are similarly described. The lobster S27E protein contains the highly conserved cysteine residues, suggesting its likely designation in the C-4 protein family containing zinc finger motifs. The lobster S27E protein also appears to have an intermediate gene copy number between lower and higher euckaryotes. Expression of the S27E protein in lobster hepatopancreas was slightly elevated during several postmolt and premolt stages. Chlorinated pesticide treatment significantly reduced S27E expression in hepatopancreas, indicating that this gene is responsive to endogenous and exogenous cues.
Souheil, H., Vey, A., Thuet, P., and Trilles, J. P. (1999). Pathogenic and toxic effects of Fusarium oxysporum (Schlecht.) on survival and osmoregulatory capacity of Penaeus japonicus (Bate). Aquaculture 178, 209-224.
A gill-blackening disease in Penaeus japonicus was caused by Fusarium oxysporum, now considered for the first time to be a parasite of this shrimp. Two different isolates of a strain of F. oxysporum, I-1 and I-2, have been used in our experiments. In I-2 treated for 3 days with antibiotics, sporulation and growth were inhibited compared to I-1 treated for only 3 h. The pathogenic effect of F. oxysporum is dose- and isolate- dependent. With isolate I-1, all inoculated animals died within 14 days and their gills were covered in black patches, although they showed no signs of reduced behavioural activity. In contrast, with isolate I-2, all animals died later within 22 days and gill lesions produced were Limited but, nevertheless, the behaviour activity of the animals was significantly reduced. Moulting or exposure to low salinities increased animal mortality. In juvenile animals, infection by F. oxysporum resulted in a significant decrease in their hypoosmoregulatory capacity (hypo-OC) in seawater and in their hyper-osmoregulatory in diluted medium. Injections of crude filtrates from shake cultures of the fungus showed that molecules greater than 6-8 kDa caused a significant decrease in the hypo-OC and are likely to be responsible for the toxic effects of this fungus on these animals. (C) 1999 Elsevier Science B.V. All rights reserved.
Soyez, D., Noel, P. Y., Van Deijnen, J. E., Martin, M., Morel, A., and Payen, G. G. (1990). Neuropeptides from the sinus gland of the lobster Homarus americanus: Characterization of hyperglycemic peptides. Gen Comp Endocrinol 79, 261-74.
In order to characterize hyperglycemic peptides from the sinus gland of the lobster, Homarus americanus, a bioassay was developed with juvenile H. gammarus. This assay was used for determining the hyperglycemic activity of peptides perified by reversed-phase high-performance liquid- chromatography, from acidic extracts of sinus gland. The major peptides are eluted in three sets of two peptides. Among them, two pairs show hyperglycemic activity when assayed on lobster; when assayed on crayfish, three peptides are active. The less hydrophobic pair consists of basic peptides (pI: 8.7), with a MW of 8633 Da., determined by fast- atom bombardment mass spectrometry. The most hydrophobic pair consists of acid peptides (pI: 5.0), with a MW of 8577 Da. Amino acid composition of the hyperglycemic peptides shows strong homologies within each pair.
Soyez, D., Le Caer, J. P., Noel, P. Y., and Rossier, J. (1991). Primary structure of two isoforms of the vitellogenesis inhibiting hormone from the lobster Homarus americanus. Neuropeptides 20, 25-32.
The amino acid sequence of two isoforms of the Vitellogenesis Inhibiting Hormone from the lobster Homarus americanus (one biologically active and one inactive in a heterologous bioassay) has been established by gas-phase microsequencing and fast-atom bombardment mass spectrometry. These two isoforms, isolated from sinus glands display the same sequence of 77 amino acid residues (m.w.: 9135 Da) and have a free N-terminus. Structurally related to Crustacean Hyperglycemic Hormone and Molt Inhibiting Hormone, the Vitellogenesis Inhibiting Hormone of the lobster clearly appears as an original member of the newly described family of neuropeptides, so far proper to crustaceans, which are involved in the control of major physiological functions.
Soyez, D. (1997). Occurrence and diversity of neuropeptides from the crustacean hyperglycemic hormone family in arthropods - A short review. In "Neuropeptides in Development and Aging", Vol. 814, pp. 319-323.
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Soyez, D., Laverdure, A. M., Kallen, J., and Van Herp, F. (1998). Demonstration of a cell-specific isomerization of invertebrate neuropeptides. Neuroscience 82, 935-42.
Neurohemal organs of the lobster Homarus americanus contain isoforms of the crustacean hyperglycemic hormone, which differ by the third amino acid (phenylalanyl) residue that is either in the L- or in the D- configuration. Polyclonal antisera have been raised in rabbit against synthetic octapeptides with the sequence corresponding to the N- terminal part of the L- or D-phenylalanine-containing isoforms. Their specificity was shown by immunoassays, indicating that they discriminate the isoforms of the lobster hyperglycemic neuropeptides. It was demonstrated that the two major forms of the crayfish Orconectes limosus hyperglycemic hormone also correspond to peptide isomers containing the L- or D-phenylalanyl residue. The cellular distribution of the isoforms among the neurosecreting cells of the major neuroendocrine complex in lobster and crayfish has been studied by immunohistochemistry. Every hyperglycemic hormone-containing cell was labelled with the anti-L antisera while only some of them were visualized with the anti-D antisera. These results constitute the first observation of peptide isomerization at the cellular level and suggest that the isomerization process occurs in specialized neuroendocrine cells.
Spanier, E., McKenzie, T. P., Cobb, J. S., and Clancy, M. (1998). Behavior of juvenile American lobsters, Homarus americanus, under predation risk. Marine Biology 130, 397-406.
The influence of predation risk and food deprivation on the behavior and activity of juvenile American lobsters, Homarus americanus Milne Edwards, was examined in single and paired individuals in laboratory experiments performed during 1988 and in the winter of 1991/92. In the presence of a predator (the tautog Tautoga onitis Linnaeus) restrained behind a barrier, single lobsters significantly reduced the time spent feeding at night, consumed fewer mussels, and quickly brought them back to shelter. Single lobsters did not forage during the day in any treatment. If deprived of food for 60 h, they consumed more mussels and spent more time walking than recently fed (12-h food-deprived) lobsters. Paired lobsters did forage during the day in the presence of a predator. The smaller lobsters (subdominant) in the pairs foraged for a longer time in the presence than in the absence of a predator and significantly longer than single individuals. Shelter occupancy was significantly shorter in single? recently fed lobsters in the presence of a predator compared to time spent sheltering in its absence. Among food-deprived lobsters? paired individuals spent a significantly shorter time within the shelter than single lobsters in the absence of a predator. Larger (dominant) lobsters, however, spent more time than subdominant lobsters within the shelter during all periods of the day. Without a predator, paired lobsters spent significantly more time than single ones in shelter-related activities. Under predation risk, subdominant lobsters concentrated shelter-building time during the day and built a higher percent of alternative shelters than either single or dominant lobsters. In the absence of a predator, paired lobsters walked in the open area for a significantly longer time than single ones in the absence of a predator. This apparently was associated with fighting between dominant and subdominant lobsters and the attempts of the larger lobster to drive the smaller one from its shelter. During the day, lobsters fought for a significantly longer time in the presence than in the absence of a predator. When the tautog was not constrained, mortality rate was similar in both single and paired lobsters. Mortality rate among subdominant lobsters, however, was seven times higher than among dominant lobsters. We suggest that the risk of predation interferes with the ability of single juvenile lobsters to acquire and consume food. They appear to trade off energetic consideration against risk of predation when foraging away from the shelter. The introduction of a conspecific competitor to the system may further increase risk (of the subdominant) to the predator. Intraspecific interactions tend to increase the risk of predation to smaller lobsters but increase the survival rate among larger lobsters.
Spanoghe, P. T., and Bourne, P. K. (1997). Relative influence of environmental factors and processing techniques on Panulirus cygnus morbidity and mortality during simulated live shipments. Marine and Freshwater Research 48, 839-844.
In this study, conducted in collaboration with the Western Australian rock lobster industry during the 1992-93 fishing season, daily records were made on morbidity and mortality of western rock lobsters, Panulirus cygnus, held in commercial shipping (export) cartons. The aims were to measure the rates of morbidity + mortality and to identify patterns of correlation of morbidity + mortality rates for a range of environmental variables recorded by the processors. In three processing units, the rate of morbidity + mortality in simulated live shipments averaged 5.2% (+/- 0.6), with a highly significant difference (P<0.001) between processing units. Three factors, holding time in export cartons, ambient temperature within the export cartons and chilling period before packing lobsters, had the greatest influence on the rate of morbidity + mortality. Morbidity + mortality rate of animals held for 30-36 h (10.4 +/- 2.3%) was twice that of animals held for 20-24 h (5.2 +/- 0.6%). A positive significant correlation (r = 0.25, P = 0.001) was identified between morbidity + mortality rate and the internal carton temperature. A prolongation of the chilling period was reflected by improved survival, possibly resulting from an anaesthesic effect of the chilling treatment.
Spaziani, E., DeSantis, K., Orourke, B. D., Wang, W. L., and Weld, J. D. (1997). The clearance in vivo and metabolism of ecdysone and 3- dehydroecdysone in tissues of the crab Cancer antennarius. Journal of Experimental Zoology 279, 609-619.
The Y-organs of Cancer antennarius secrete the hormones ecdysone (E) and much greater amounts of 3-dehydroecdysone (3DE), but the dominant derivative in the circulation is 20- hydroxyecdysone (20E). The uptake and clearance of E, 3DE, and metabolites were compared in selected tissues in vivo, and the capacity of each to generate 20E was assessed in vitro. [H-3]- labeled E or 3DE, injected into intermolt crabs, rapidly cleared from hemolymph, while being taken up and then rapidly cleared from tissues (muscle, heart, epidermis, ovary) within 1 h. Labeled 20E from E or 3DE appeared in all tissues in the first hour, cleared to varying degrees from tissues, and then reaccumulated over 24 h. Among these tissues, ovary accumulated the most labeled 20E. Generally by 24 h more labeled 20E accumulated from 3DE than from E. Excising the eyestalks (inducing premolt) did not affect the outcomes except that deeyestalking caused much greater concentrations of 3DE than E to appear in all tissues initially. Tissue extracellular volumes ([C-14]inulin spaces) were not altered by deeyestalking, except transiently in epidermis, and otherwise did not account for the observed ecdysteroid dynamics. A parallel study with eyestalk neural tissue from crabs receiving [H-3]3DE showed extraordinary accumulation of 3DE and labeled metabolites. The normalized tissue/hemolymph ratio was 72 at 8 h, compared with 0.6-2.6 for other tissues. The apparent extracellular volume of eyes was high (80%) but did not account for the high ecdysteroid accumulation. Tissues were incubated 18 h with [H-3]3DE. Activities representing 3 beta-reductase and 20-hydroxylase generally were present, evidenced by finding labeled E and 20E. Tissue blanks, hemolymph, and muscle were devoid of activity, hepatopancreas and epidermis were intermediate, ovary, testis, and hindgut were high, and eyestalk tissue was highest in activities. Low amounts of labeled high-polar material were usually present, and a labeled derivative tentatively identified as 3-dehydro-20- hydroxyecdysone (3D20E) also appeared in ovary, hepatopancreas, hindgut, and eyes, indicating some direct conversion of 3DE to 3D20E. In composite, these data indicate that 3DE secreted by Y-organs is converted to E, thence to 20E by several tissues, accounting for the preponderance of 20E in crustacean hemolymph. The findings support the hypotheses that 20E is the definitive molting hormone (receptor ligand) and that an ecdysteroid feedback mechanism controls release of the molt- inhibiting hormone from the eyestalks. (C) 1991 Wiley-Liss, Inc.
Speare, D. J., Cawthorn, R. J., Horney, B. S., MacMillan, R., and MacKenzie, A. L. (1996). Effects of formalin, chloramine-T, and low salinity dip on the behavior and hemolymph biochemistry of the American lobster. Can Vet J 37, 729-34.
The purpose of this research was to investigate the salinity and formalin sensitivity of a ciliate parasite (Anophryoides haemophila) of the American lobster (Homarus americanus), and to examine the target- animal (lobster) safety of chemical-bath treatments involving low salinity, formalin, or chloramine-T that could be used to control this parasite in lobster pounds. "Bumper car" disease, caused by An. haemophila, is an important concern to lobster pound operators in eastern North America, because of the implicated lobster mortality rate and the general lack of preventive and therapeutic intervention regimes. We determined, using an in vitro method, that formalin at 50 mg/L, or low salinity at 8.0 parts per thousand (ppt) for 1 hour killed 100% of the parasites. When healthy lobsters were exposed to formalin at 200 mg/L, there were no negative behavioral responses and no significant differences in a panel of hemolymph biochemical indices. Similar results occurred when lobsters were exposed to chloramine-T, a common finfish therapeutic agent for topical bacteria and protozoa, at 10 mg/L for 1 hour. The low salinity treatment (8.0 ppt) resulted in significant adverse changes in lobster behavior and biochemical indices; however, these changes did not persist for more than 1 week after treatment ended. Although these treatments are unlikely to kill parasites that have already invaded the lobster carapace, they should be effective in reducing parasite loads on the gill and carapace surface of the lobster and in the environment of the impoundment housing.
Spoek, G. L. (1967). The influence of salts on the binding of oxygen by the haemocyanin of the lobster Homarus gammarus L. Acta Physiol Pharmacol Neerl 14, 506-7.
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Spycher, S. E., Arya, S., Isenman, D. E., and Painter, R. H. (1987). A functional, thioester-containing alpha 2-macroglobulin homologue isolated from the hemolymph of the American lobster (Homarus americanus). J Biol Chem 262, 14606-11.
An alpha 2-macroglobulin-like protease inhibitor was isolated from the cell-free hemolymph of the american lobster (Homarus americanus) by ion- exchange chromatography and gel filtration. Whereas the undissociated molecule has a molecular weight of 342,000 as determined by ultracentrifugation studies, under reducing sodium dodecyl sulfate- polyacrylamide gel electrophoresis, the protein has a subunit molecular weight of 180,000. On the basis of this and other evidence, we conclude that the lobster protein is a dimer consisting of two disulfide-bonded monomers. The purified protein inhibits proteolytic enzymes but protects the esterolytic activity of trypsin toward low molecular weight substrates from inactivation by soybean trypsin inhibitor. The methylamine sensitivity of this activity suggests the presence of an internal thioester bond. This was confirmed by the covalent incorporation of [14C]methylamine, by the formation of Mr 55,000 and 125,000 autolytic cleavage fragments in sodium dodecyl sulfate- polyacrylamide gel electrophoresis, and, more directly, by the amino acid sequence of a tryptic peptide containing the putative thioester region. Whereas the N-terminal amino acid sequence (22 residues) of the protein revealed an overall identity of only 18% when compared with the human protein, the sequence of the thioester-containing peptide was highly conserved, both with respect to human alpha 2-macroglobulin and to other proteins having a thioester bond. The protein showed the "slow to fast" conformational change typical in alpha 2-macroglobulins in nondenaturing gel electrophoresis after treatment with trypsin, but not after incubation with methylamine.
Srivastava, R., Lau, D., and Goldsmith, T. H. (1996). Formation and storage of 11-cis retinol in the eyes of lobster (Homarus) and crayfish (Procambarus). Vis Neurosci 13, 215-22.
Modes of storage and mechanisms of formation of 11-cis retinoids in the eyes of animals vary widely among the major phyla. We here describe evidence from two species of macruran decapod crustacea that point to different processes from those known in insects, the other group of arthropods for which there is extensive data. The eyes of the lobster (Homarus) contain about 300 pmol of retinal, somewhat less free retinol, and variable amounts (up to 1000+ pmol) of two retinyl esters, over 90% of which contain retinol in the 11-cis configuration. The major ester contains the long chain, polyunsaturated fatty acid docosahexaenoate (C22:6), but retinyl oleate (C18:1) is also present. Crayfish (Procambarus) contain the same retinyl esters, although in much smaller amounts. Homogenates of the eyes of both species are capable of isomerizing all-trans retinyl docosahexaenoate to the 11-cis configuration without using the energy of light. Crude fractionation of homogenates shows isomerase activity associated with membranes. The reaction mechanism has not been explored in detail, but on the basis of present evidence it may be similar to that found in vertebrate pigment epithelium. It is clearly different from the light-dependent processes known in insects (Hymenoptera and Diptera) and cephalopod mollusks, where isomerization takes place at the level of the aldehyde and 11-cis retinyl esters are not present as major storage reserves.
Stauber, W. T., Canonico, P. G., Milanesi, A. A., and Bird, J. W. (1975). Lysosomal enzymes in aquatic species. IV. Distribution and particle properties of muscle lysosomes of the lobster, Homarus americanus. Comp Biochem Physiol [B] 50, 379-84.
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Steele, C., Skinner, C., Alberstadt, P., and Mathewson, C. (1999). Organization of chemically activated food search behavior in Procambarus clarkii Girard and Orconectes rusticus Girard crayfishes. Biological Bulletin 196, 295-302.
The feeding responses of decapod crustaceans to chemical stimuli have most often been evaluated in terms of one defining act, ignoring the organization of the behavior. To gain greater insight into foraging behavior, we considered the organization of food-search behavior in evaluating the responses of two species of crayfishes to a feeding stimulant. We also examined the effects of food deprivation on the behavioral organization and whether a behavioral dichotomy exists between food search and feeding behavior in these species. Individual crayfish of the species Procambarus clarkii and Orconectes rusticus were presented with infusions of a feeding stimulant consisting of a supernatant leachate of 100 mi water and 1 g of fish flakes. The stimulant was injected with a syringe and small-bore plastic infusion tubing into the center of a behavioral arena 25 cm square and 15 cm deep. Total injection time was 20 s. Experimental groups were presented with either the full- strength leachate (100%) or one of five dilutions: 75%, 50%, 25%, 10%, or 0% (controls) of full-strength. The feeding stimulant was presented either the day after the crayfish were fed or after one week of food deprivation. We analyzed three components of food-search behavior-detection, probing (nearfield search), and locomotion (far-field, or distant, search)-recording the order of occurrence and the latency time to initiation for each behavior. When presented with the stimulus following regular feeding, both species responded to concentrations greater than or equal to 50% full strength with probing behavior (near-field search) prior to locomotion, and to concentrations <50% full-strength with locomotion prior to, or even in the absence of, probing. Detection always occurred first. These results indicate that chemical stimuli preferentially activate distant food search in both species and that a behavioral dichotomy exists between food search and feeding behavior. One week of food deprivation had no effect on the organization of food-search behavior in P. clarkii; however, groups of unfed O. rusticus presented with 25% and 10% full-strength concentrations probed prior to locomotion, indicating a change in behavioral organization.
Steenbergen, J. F., Kimball, H. S., Low, D. A., Schapiro, H. C., and Phelps, L. N. (1977). Serological grouping of virulent and avirulent strains of the lobster pathogen Aerococcus viridans. J Gen Microbiol 99, 425-30.
Virulent strains of Aerococcus viridans (formerly Gaffkya homari) are the aetiologic agents of gaffkemia, a septicaemic disease of the American lobster (Homarus americanus). The virulent and avirulent forms of this bacterium, previously thought to be taxonomically indistinguishable, have been differentiated by serological studies. Antisera were produced in rabbits using autoclaved bacteria as antigens. Reactions were measured by agglutination tests using microtitre techniques and an antigenic scheme was determined. Specific antisera were prepared by absorption and used to determine antigens of strains of A. viridans and other Gram-positive cocci. In general, only virulent strains of A. viridans have antigen b. Both virulent and avirulent strains possess other antigens also detected in strains of the genus Staphylococcus.
Stein, E. A., Younai, S., and Cooper, E. L. (1987). Hemagglutinins and bacterial agglutinins of earthworms. Prog Clin Biol Res 233, 79-89.
The biological roles of invertebrate agglutinins have been and remain an unresolved subject of controversy. Classical studies on agglutinins, beginning with the pioneer work of Noguchi (1903) on Limulus polyphemus and Homarus americanus have emphasized their hemagglutinating properties, an approach that has been criticized for its lack of biological relevance. While erythrocyte agglutination has proven useful for determining various properties of invertebrate agglutinins, it does not address the question of their natural function. More recently, invertebrate agglutinins have been investigated for their ability to interact with pathogenic agents such as bacteria (for review, see Pistole, 1982), yeast (Van der Knapp et al., 1982; Renwrantz and Stahmer, 1983) and parasitic protozoans (Ingram et al., 1984). In addition, the possible relationship of agglutinins to defense mechanisms of both vertebrates and invertebrates has been indicated by the observation that limulin, the major agglutinin of Limulus polyphemus, bears a number of similarities to vertebrate C-reactive proteins (Robey and Liu, 1981). In annelids, there have been no studies on bacterial agglutinins prior to our work with Lumbricus (Stein et al., 1985; Stein et al., submitted). Earthworms are particularly appropriate for studying bacterial agglutinins since their coelomic fluid contains constant low levels of bacteria and fungal spores, and their agglutinins are both naturally occurring and inducible. Although our initial studies on Lumbricus agglutinins were directed toward their hemagglutinating properties, our recent observations using bacteria have allowed us to reach the following conclusions: 1) Lumbricus coelomic fluid normally contains agglutinins against both erythrocytes and bacteria. After injecting worms with either erythrocytes or bacteria, agglutinin titers increase in coelomic fluid. This increase appears to be due to both an increase in numbers of agglutinins as well as levels of specific agglutinins. 2) Absorption studies, temperature effects and sugar inhibition analyses suggest that agglutinins which bind to erythrocytes are identical to bacterial agglutinins, but there are additional agglutinins capable of reacting only with bacteria. 3) The inducibility and bacterial binding properties of Lumbricus agglutinins suggest that they serve an immune function by participating in the earthworm's defense against bacterial infection. In this sense, the agglutinins serve as a humoral surveillance system that entraps and prevents the multiplication of pathogenic bacteria.
Stent, G. S., Thompson, W. J., and Calabrese, R. L. (1979). Neural control of heartbeat in the leech and in some other invertebrates. Physiol Rev 59, 101-36.
The heartbeat of the leech Hirudo consists of the contractile rhythm of the circular muscles in the wall of a bilateral pair of celomic sinuses, the heart tubes, that run the length of the leech body. The constriction cycles of the segmental heart-tube sections are coordinated so that on one body side they constrict in a rear-to-front progression (peristalsis), while on the other side they constrict nearly in concert (nonperistalsis). Spontaneous right-left reciprocal transitions between peristaltic and nonperistaltic coordination modes occur every few dozen heartbeat cycles. The constriction of each segmental heart-tube section is controlled via excitatory synapses by a rhythmically active heart motor neuron, or HE cell, of which 17 bilateral pairs are iterated in segmental ganglia of the ventral nerve cord. The activity rhythm of the HE cell ensemble is in turn controlled via inhibitory synapses by a rhythmically active heart interneuron, the HN cell, of which seven bilateral pairs are iterated in the rostral segmental ganglia. The HN heart interneuron owes its activity rhythm to an endogenous polarization cycle, and the cycles of all members of the HN cell ensemble are locked into an appropriate phase relation thanks to their mutual interconnection via excitatory and inhibitory synaptic connections. The observed activity pattern and identified synaptic connections of HE cells and HN cells can account not only for the generation of the two bilaterally asymmetric heartbeat coordination modes but also for the right-left coordination mode transitions. In contrast to the heartbeat of Hirudo, the beat of the single-chambered heart of the lobsters Panulirus and Homarus is controlled by a set of nine rhythmically active neurons that make up the cardiac ganglion. Of these, five larger cells are heart motor neurons that innervate the heart muscle fibers via excitatory synapses. The remaining four smaller neurons of the cardiac ganglion are interneurons that provide excitatory input to each other and to the heart motor neurons. Although all the neurons of the cardiac ganglion appear capable of producing their own endogenous polarization rhythm, it is currently believed that one of the interneurons acts as a pacemaker for the whole ensemble of interneurons and motor neurons. The beat of the two-chambered heart of the marine snail Aplysia is generated by yet an entirely different mechanism. Here, the basic contractile rhythm of the heart is due to an endogenous polarization cycle of the heart muscle fibers. That myogenic rhythm is controlled and modulated by a set of cardiovascular motor neurons located in the abdominal ganglion, some of which make excitatory and others of which make inhibitory connections with the heart muscle fibers. The activity of these cardiovascular motor neurons is controlled by three types of heart interneurons via both inhibitory and excitatory connections. The interneurons are in turn interconnected in a manner that prevents the simultaneous activation of antagonistic cardiac motor acts...
Stetten, M. R., and Goldsmith, P. K. (1981). Two hexokinases of Homarus americanus (lobster), one having great affinity for mannose and fructose and low affinity for glucose. Biochim Biophys Acta 657, 468-81.
Two major hexokinases (ATP: D-hexose 6-phosphotransferases, EC 2.7.1.1) have been identified in tissues of Homarus americanus (lobster) and separated from each other by DEAE-cellulose ion-exchange chromatography and by polyacrylamide gel electrophoresis. The molecular weight of each, determined by gel filtration, is about 50 000. Hexokinase II, named for its column elution order, resembles hexokinase isozymes I and II of vertebrates. Km values for glucose, mannose and fructose are 0.08, 0.13 and 6.7 mM, respectively. It is strongly inhibited by the reaction products, ADP and glucose-6-P (Ki = 0.8 mM). Hexokinase I appears to be different from any animal hexokinase previously described. It has a high affinity for mannose and fructose and low affinity for glucose. Km values are 6, 0.07 and 1.2 mM and relative maximum rates 100, 520 and 1070 for glucose, mannose and fructose, respectively. Hexokinase I is not inhibited by physiological concentrations of ATP nor by glucose-6-P , mannose-6-P or fructose-6-P even at high concentrations. Both enzymes occur in muscle at about 10% of the concentration found in the hepatopancreas. The use of Leuconostoc mesenteroides glucose-6-phosphate dehydrogenase (D-glucose- 6-phosphate: NADP+ 1-oxidoreductase, EC 1.1.1.49), with NAD as cofactor, is recommended for measuring hexokinases in crude tissue preparations to avoid the variable further reduction of nucleotide caused by the action of 6-phosphogluconate dehydrogenase when NADP is used with yeast glucose-6-phosphate dehydrogenase.
Stewart, J. E., Arie, B., Zwicker, B. M., and Dingle, J. R. (1969). Gaffkemia, a bacterial disease of the lobster, Homarus americanus: effects of the pathogen, Gaffkya homari, on the physiology of the host. Can J Microbiol 15, 925-32.
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Stewart, J. E., and Cornick, J. W. (1972). Effects of Gaffkya homari on glucose, total carbohydrates, and lactic acid of the hemolymph of the lobster (Homarus americanus). Can J Microbiol 18, 1511-3.
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Stewart, J. E., and Zwicker, B. M. (1972). Natural and induced bactericidal activities in the hemolymph of the lobster, Homarus americanus: products of hemocyte-plasma interaction. Can J Microbiol 18, 1499-509.
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Stewart, J. E., and Arie, B. (1973). Depletion of glycogen and adenosine triphosphate as major factors in the death of lobsters (Homarus americanus) infected with Gaffkya homari. Can J Microbiol 19, 1103-10.
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Stocker, W., Breit, S., Sottrup-Jensen, L., and Zwilling, R. (1991). alpha2-Macroglobulin from hemolymph of the freshwater crayfish Astacus astacus. Comp Biochem Physiol [B] 98, 501-9.
1. A high mol. wt proteinase inhibitor has been purified from the haemolymph of the freshwater crayfish Astacus astacus. 2. The protein is a disulphide-bonded dimer (Mr 390,000) of two identical polypeptide chains (Mr 185,000). 3. The inhibitor displays a broad specificity and protects trypsin from inhibition by soybean trypsin inhibitor and thus is similar to vertebrate alpha 2-macroglobulin. 4. The alpha 2- macroglobulin-like inhibitor from Astacus interacts with bovine trypsin in an equimolar stoichiometry thereby decreasing tryptic hydrolysis of N-benzoyl-L-arginine-ethylester to 50% residual activity. In contrast, the activity of Astacus protease, a digestive zinc proteinase from crayfish toward succinyl-alanyl-alanyl-alanyl-4-nitroanilide is inhibited almost completely. 5. Sensitivity of the inhibitor to methylamine and autolytic cleavage suggests the presence of an internal thioester bond. 6. The N-terminal amino acid sequence of Astacus alpha 2-macroglobulin is strongly related to the alpha 2-macroglobulins from Pacifastacus leniusculus (91% identity) and from the lobster Homarus americanus (72% identity). In contrast, only 25% of the residues are identical with the alpha 2-macroglobulin from the horseshoe crab Limulus polyphemus. There is also a faint similarity to human complement protein C3 and human alpha 2-macroglobulin.
Stockmann, R., Laverdure, A. M., and Breuzet, M. (1997). Localization of a crustacean hyperglycemic hormone-like immunoreactivity in the neuroendocrine system of Euscorpius carpathicus (L.) (Scorpionida, Chactidae). Gen Comp Endocrinol 106, 320-6.
The neuroendocrine system of Euscorpius carpathicus was immunohistochemically localized using a polyclonal antiserum raised against a purified Homarus americanus crustacean hyperglycemic hormone (Hoa-cHHA). There were cross-reactions in E. carpathicus procerebral and subesophageal neurosecretory cells, neurohemal organs, and intra- and extraganglionic neurosecretory tracts. Among the neurohemal structures, the Kwartirnikov's organ, the Tropfenkomplex, and the coxal disc reacted strongly. In Euscorpius, the differing results between adults and juveniles suggest neurosecretory variations related to developmental stage. These immunohistochemical observations suggest the presence of substances related to the cHH in scorpions; however, in this heterologous system, it is not at present possible to assess physiological significance.
Stoeva, S., Dolashka, P., Hristova, R., Genov, N., and Voelter, W. (1999). Subunit composition and N-terminal analysis of arthropod hemocyanins. Comparative Biochemistry and Physiology B-Biochemistry & Molecular Biology 122, 69-75.
Fourteen structural subunits of hemocyanins from two different infraorders of crustacea, brachyura (Maia squinado, Carcinus maenas) and astacidea (Homarus americanus) were isolated and characterized. N-terminal amino acid sequences were determined and compared with known sequences of crustacean and cheliceratan hemocyanins. Relationships between the investigated polypeptide chains were established. The results demonstrate that the degree of identity, calculated from the amino terminal sequences, is lower than that determined from the complete sequences and can be used for reliable characterization of the whole individual subunits. Independent evolution is possible not only for members of different subphyla, but also for those from one infraorder or from the same hemocyanin. (C) 1999 Elsevier Science Inc. All rights reserved.
Strichartz, G. R., and Hanson Bay, C. M. (1981). Saxitoxin binding in nerves from walking legs of the lobster Homarus americanus. Two classes of receptors. J Gen Physiol 77, 205-21.
The binding of exchange-labeled saxitoxin (STX) to sodium channels has been investigated in the nonmyelinated fibers of the walking leg nerves of the lobster. The properties of the STX binding site differed systematically among the nerves from different walking legs. The equilibrium dissociation constant for STX binding (KSTX) to the front legs is approximately twice that for the binding to the rear legs; the average ratio of KSTX (front): KSTX (rear) from five separate experiments was 1.80 +/- 0.21 (mean +/- SE). The actual KSTX values ranged from 124.0 to 22.7 nM for the front leg nerves and from 8.6 to 12.7 nM for the rear leg nerves. KSTX values for the middle two walking leg nerves fell between those for the front and rear legs. The inhibitory dissociation constant for tetrodotoxin (KTTX), calculated from tetrodotoxin's inhibition of labeled STX binding, was 3.02 +/- 0.27 nM for the front legs and 2.20 +/- 0.33 nM for the rear legs. The ratio KSTX: KTTX was different in the front and rear leg nerves, being 5.5 and 4.2, respectively. The apparent P pKa of the STX receptor also differed between the two legs, being 4.6 +/- 0.3 for the front legs and 5.1 +/- 0.1 for the rear legs. These results demonstrate that one tissue type in one organism can contain different toxin binding sites. The difference in the receptors can be qualitatively accounted for by the location of an additional negative charge near the receptor site of the rear walking leg.
Subramoniam, T. P., Reichwein, B., Dircksen, H., and Keller, R. (1998). On the isolation and characterisation of a crustacean hyperglycaemic hormone in the eyestalk of the shrimp Penaeus indicus. Aquaculture 162, 99-111.
In decapod crustaceans, the eyestalk represents the pivotal source for several neuropeptides influencing various physiological activities concerned with metabolism, growth and reproduction. Prominent among them is-the crustacean hyperglycaemic hormone (CHH) which regulates the blood glucose level by its 'diabetogenic' action. This paper reports on the first characterisation of a CHH in the commercially important penaeid species Penaeus indicus. Reversed phase HPLC of extracts from eyestalk ganglia on a Waters mu-Bondapak phenyl column combined with an enzyme linked immunosorbent assay revealed that among six immunoreactive peptide fractions in total a late eluting peak fraction,with the retention time of about 50 min shows the strongest immunoreactivity to a polyclonal rabbit antiserum raised against the CHH of the freshwater crayfish Orconectes limosus. The amino acid composition of this peptide, purified by rechromatography was determined according to the orthophthaldialdehyde post column derivatisation method. The most interesting features are the low molar concentration of acidic amino acid residues (e.g. Asx, Glx) but a high molar concentration of lysine residues. The CHH material was localised immunocytochemically in the neurosecretory centres of X-organ sinus gland system using the same antiserum. A large number of perikarya of the medulla terminalis X-organ, the neural tract as well as the sinus gland showed intense immunoreactivity. Though the hyperglycaemic response of this HPLC purified CHH of P. indicus was found to be very poor when injected into eyestalkless as well as eyestalk-intact crayfish, O. limosus, it clearly induced hyperglycaemia in P. indicus. (C) 1998 Elsevier Science B.V.
Subramoniam, T. (1999). Endocrine regulation of egg production in economically important crustaceans. Current Science 76, 350-360.
Significant advances have been made in crustacean reproductive endocrinology, especially in view of its application potential in aquaculture. Major contribution is in the isolation, characterization as well as functional role of eye-stalk neuropeptides, which control diversified physiological functions, including egg production. Their specific control over proximate endocrine glands such as mandibular organ and Y- organ has relevance to the formulation of control methods to enhance egg production in the commercially important crustaceans. Neuropeptide diversity as well as multiple peptide actions in the crustaceans call for intensified work in the field to gain greater understanding towards their possible use in reproductive control. Plausibility of biogenic amines and endogenous vertebrate-type steroids in the control of reproduction indicates the complexity of crustacean endocrinology as well as their use in the formulation of control measures. A need for understanding the vitellogenic processes together with the tissue response to various endocrine factors in controlling reproduction is also stressed.
Sugumaran, M., and Nellaiappan, K. (1991). Lysolecithin--a potent activator of prophenoloxidase from the hemolymph of the lobster, Homarus americanas. Biochem Biophys Res Commun 176, 1371-6.
The phenoloxidase system, which is involved in encapsulation and melanization of foreign objects in crustacean, is found to be present in an inactive proenzyme form in the hemocytes of the lobster, Homarus americanas. Activation of the enzyme could be achieved either by treatment with an anionic detergent such as sodium dodecyl sulfate, or by a cationic detergent such as cetylpyridinium chloride, but not by either nonionic detergent or zwitterionic detergent. In addition, a number of fatty acids also activated the proenzyme. However, phospholipids, especially lysolecithin proved to be the most potent activator of prophenoloxidase. Therefore, it is proposed that apart from the well established proteolytic mode of activation, prophenoloxidase can also be activated by this alternative mode involving lipids.
Sukhdeo, S. C., and Page, C. H. (1992). Abdominal postural motor responses initiated by the muscle receptor organ in lobster depend upon centrally generated motor activity. J Exp Biol 162, 167-83.
1. Stretch stimulation of the abdominal muscle receptor organ of the lobster Homarus americanus initiated spike discharge of its tonic sensory neuron (SR1). This sensory response evoked a series of tonic postural reflex responses in the motor neurons that innervate the superficial extensor and flexor muscles of the abdominal postural system. The type of motor response depended on whether a flexion or extension pattern of spontaneous activity was being generated by the postural efferents. Spontaneous shifts between these centrally generated motor activities completely changed the SR1-evoked reflex responses. 2. During spontaneous centrally initiated flexion activity, tonic SR1 neuron discharge elicited an assistance response that included excitation of a medium-sized flexor excitor (f3) and the peripheral extensor inhibitor (e5), and inhibition of at least one extensor excitor. Neither the other flexor excitors nor the peripheral flexor inhibitor (f5) were affected by SR1 excitation. 3. During spontaneous centrally initiated extension activity, SR1 activity elicited a response that included excitation of the extensor excitors and the flexor peripheral inhibitor (f5) only, f3 and e5 spontaneous activities were unchanged. This response was a resistance reflex, since SR1 discharge normally resulted from an imposed abdominal flexion. 4. The SR1-initiated control of postural motor activity in lobster differs from previously published results in the crayfish Procambarus clarkii.
Sullivan, R. E., and Miller, M. W. (1984). Dual effects of proctolin on the rhythmic burst activity of the cardiac ganglion. J Neurobiol 15, 173-96.
The neuropeptide proctolin has distinguishable excitatory effects upon premotor cells and motorneurons of Homarus cardiac ganglion. Proctolin's excitation of the small, premotor, posterior cells is rapid in onset (5-10 s) and readily reversible (less than 3 min). Prolonged bursts in small cells often produce a "doublet" ganglionic burst mode via interactions with large motorneuron burst-generating driver potentials. In contrast to small cell response, proctolin's direct excitatory effects upon motorneuron are slow in onset (60-90 s to peak) and long-lasting (10-20 min). The latter include: a concentration- dependent (10(-9)-10(-7)M) depolarization of the somatic membrane potential; increases in burst frequency and enhancement of the rate of depolarization of the interburst pacemaker potential. Experiments on isolated large cells indicate: the slow depolarization is produced by a decrease in the resting GK and proctolin can produce or enhance motorneuron autorhythmicity . A two- tiered non-hierarchical network model is proposed. The differential pharmacodynamics exhibited by the two cell types accounts for the sequential modes of ganglionic burst activity produced by proctolin.
Sun, P. S. (1994). Molecular cloning and sequence analysis of a cDNA encoding a molt- inhibiting hormone-like neuropeptide from the white shrimp Penaeus vannamei. Mol Mar Biol Biotechnol 3, 1-6.
The X-organ of the eyestalk in crustaceans is a source of neurosecretory peptides. Total RNA was isolated from X-organs of the white shrimp Penaeus vannamei and used to clone a cDNA encoding a molt- inhibiting hormone-like (MIH-like) neuropeptide by the 3' and 5' rapid amplification of cDNA ends (RACE) method. Sequence analysis of the 470- bp cDNA reveals a 306-bp open reading frame and a 164-bp 3' untranslated region. The deduced polypeptide consists of a 72-amino acid mature peptide and a 30-amino acid region of propeptide. The mature peptide shares 49 and 29% amino acid identity to the MIH from the lobster Homarus americanus and the crab Carcinus maenas, respectively. Northern hybridization shows that the MIH-like mRNA has a molecular size of 2.0 kb and is present in the eyestalk.
Taggart, P., and Landau, M. (1992). Characterization of a G-protein from the mandibular organ of the lobster Homarus americanus (Nephropidae, Decapoda). Comp Biochem Physiol [B] 102, 799-802.
1. GTP-binding activity was found in both calf brain and male lobster mandibular organ (MO). There was approximately two to three times as much binding in the calf brain. 2. The GTP-binding activity could be extracted from the calf brain with sodium cholate, but not from the MOs. 3. Using ADP-ribosylation catalyzed by pertussis toxin, GTP- binding was shown to be the result of the presence of G-protein. In the lobster MO the G-protein alpha subunit has a molecular weight of about 42 kDa and may be of the Go or Gi varieties.
Talbot, P., and Chanmanon, P. (1980). The structure of sperm from the lobster, Homarus americanus. J Ultrastruct Res 70, 275-86.
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Talbot, P., and Chanmanon, P. (1980). Morphological features of the acrosome reaction of lobster (Homarus) sperm and the role of the reaction in generating forward sperm movement. J Ultrastruct Res 70, 287-97.
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Talbot, P. (1981). The ovary of the lobster, Homarus americanus. II. Structure of the mature follicle and origin of the chorion. J Ultrastruct Res 76, 249-62.
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Talbot, P. (1981). The ovary of the lobster, Homarus americanus. I. Architecture of the mature ovary. J Ultrastruct Res 76, 235-48.
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Talbot, P., and Goudeau, M. (1988). A complex cortical reaction leads to formation of the fertilization envelope in the lobster, Homarus. Gamete Res 19, 1-18.
We have examined the formation of the fertilization envelope in the lobsters Homarus americanus and H gammarus. Oocytes were fixed for electron microscopy either in the ovary or following extrusion from the gonopore. Mature ovarian oocytes are surrounded by a coat (envelope 1), which is comprised of small electron-dense granules and structures resembling "bottlebrushes." At least part of this coat is synthesized by the follicle cells of the ovary. The cortex of ovarian oocytes contains four types of vesicles that we refer to as high-density vesicles (HDV), low-density vesicles (LDV), moderately dense vesicles (MDV), and ring vesicles (RV). Oocytes that were electrically extruded from the gonopore and fixed immediately had an envelope identical to that of ovarian oocytes. The cortex of gonopore oocytes contained the four types of vesicles found in ovarian oocytes. When unfertilized gonopore oocytes were allowed to incubate in sea water, the oocyte cortex appeared unaltered, but envelope 1 swelled and the bottlebrushes dispersed. When recently fertilized oocytes were fixed during natural spawning or following in-vitro fertilization, each type of vesicle was released in sequence from the cortex of the oocyte. The contents of the HDV and LDV appeared first in the perivitelline space, but their fate could not be determined at later times. The ring-shaped elements of the RV and the moderately electron-dense material of the MDV were released exocytotically somewhat later; these materials coalesced in the perivitelline space to form a new coat (envelope 2). Envelope 1 subsequently condensed to its original thickness and appeared firmly attached to envelope 2. Our results show that the fertilized lobster egg is surrounded by two discrete coats. The outer coat, which is formed in the ovary, undergoes a swelling/condensation cycle at spawning. The inner coat originates from a complex cortical reaction. Together these coats comprise the fertilization envelope of the lobster egg.
Tam, Y. K., and Kornfield, I. (1996). Characterization of microsatellite markers in Homarus (Crustacea, Decapoda). Mol Mar Biol Biotechnol 5, 230-8.
Three variable microsatellite loci have been isolated from the American lobster, Homarus americanus. In a population sample from the Gulf of Maine, the effective numbers of alleles (Ne) for the two most variable loci were 16.33 and 13.19, respectively. Reduced variability at all three loci was seen in the European lobster, H. gammarus, for which the maximum Ne was 4.00. The reduction in variability in H. gammarus is consistent with a bottleneck event. Inheritance analysis using H. americanus demonstrated segregation of codominant alleles and the absence of linkage. Null alleles were observed at two loci in inheritance studies. This study demonstrates that microsatellite loci should be useful in studying the population structure of clawed lobsters.
Tam, Y. K., and Kornfield, I. (1998). Phylogenetic relationships of clawed lobster genera (Decapoda : Nephropidae) based on mitochondrial 16S rRNA gene sequences. Journal of Crustacean Biology 18, 138-146.
Approximately 350 base pairs (bp) of the mitochondrial 16S rRNA gene were used to study the phylogenetic relationships among 5 genera of the clawed lobster family Nephropidae (infraorder Astacidea), including Homarus, Homarinus, Metanephrops, Nephrops, and Nephropsis. Maximum-parsimony analysis, using a hermit crab, Pagurus pollicaris (infraorder Anomura), as an outgroup. produced a tree topology in which Homarus and Nephrops formed a well-supported clade that excluded Homarinus. The same tree topology was obtained from both neighbor-joining and maximum-likelihood analyses, Some morphological characters that appear synapomorphic for Nephrops and Metanephrops may be due to convergence rather than symplesiomorphy. The current taxonomy, therefore, does not reflect the phylogeny of this group as suggested by the molecular data. More molecular data and studies using homologous morphological characters me needed to reach a better understanding of the phylogenetic history of clawed lobsters.
Tang, J. M., Wang, J., and Eisenberg, R. S. (1989). K+-selective channel from sarcoplasmic reticulum of split lobster muscle fibers. J Gen Physiol 94, 261-78.
The patch clamp technique has been used to study channels in a membrane inside a cell. A single muscle fiber is skinned in relaxing saline (high K+, low Ca2+ with EGTA and ATP), leaving the native sarcoplasmic reticulum (SR) membrane exposed for patching. Fibers are dissected from the second antenna remotor muscles of the American lobster, Homarus americanus. Transmission and scanning electron microscopy confirm the large volume fraction of SR (approximately 70%) and absence of sarcolemma in this unusual skinned preparation. The resting potential of the SR was measured after the resistance of the patch of membrane was broken down. It is near 0 mV (-0.4 +/- 0.6 mV). The average input resistance of the SR is 842 +/- 295 M omega. Some 25% of patches contain a K+-selective channel with a mean open time of seconds and the channel displays at least two conducting states. The open probability is weakly voltage dependent, large at zero and positive potentials (cytoplasm minus SR lumen), and decreasing at negative potentials. The maximal conductance of this channel is 200 +/- 1 pS and the substate conductance is 170 +/- 3 pS in symmetrical 480 mM K+ solution. The current-voltage relation of the open channel is linear over a range of +/- 100 mV. The selectivity is similar to the SR K+ channel of vertebrates: PK/PNa is 3.77 +/- 0.03, determined from reversal potential measurements, whereas gamma K/gamma Na is 3.28 +/- 0.06, determined from open-channel conductance measurements in symmetrical 480 mM solutions. Voltage-dependent block in the lobster SR K+ channel is similar to, but distinct from, that reported for the vertebrate channels. It occurs asymmetrically when hexamethonium is added to both sides of the membrane. The block is more effective from the cytoplasmic side of the channel.
Tang, C. H., Lu, W. Q., Wainwright, G., Webster, S. G., Rees, H. H., and Turner, P. C. (1999). Molecular characterization and expression of mandibular organ- inhibiting hormone, a recently discovered neuropeptide involved in the regulation of growth and reproduction in the crab Cancer pagurus. Biochemical Journal 343, 355-360.
Methyl farnesoate, the crustacean juvenoid, is synthesized and secreted from the mandibular organs of crustaceans under the negative control of the sinus gland-derived mandibular organ- inhibiting hormone (MO-IH). Previously we isolated and sequenced two isoforms, MO-IH-1 and MO-IH-2, differing by just one amino acid, from sinus glands of the edible crab, Cancer pagurus. We now report the isolation of cDNAs encoding MO-IH-1 and MO-IH-2 by a combination of reverse-transcriptase-mediated PCR in conjunction with 5' and 3' rapid amplification of cDNA ends ('RACE'). Full-length clones of MO-IH-1 and MO-IH-2 encoded a 34-residue putative signal peptide and the mature 78- residue MO-IH sequences. Northern blot analysis of various tissues showed that MO-IH expression is confined to the X-organ (a cluster of perikarya within the eye). Southern blot analysis indicated that there are approx. 10 copies of the gene for MO- IH in C. pagurus. Additional Southern blotting experiments detected MO-IH-hybridizing bands in another Cancer species, C. antennarius. In support of this, an HPLC-radioimmunoassay analysis of sinus gland extracts of C. antennarius and C. magister also revealed MO-IH-like immunoreactivity.
Tani, M., and Kuramoto, T. (1998). Cool-sensitive neurons in the ventral nerve cord of crustaceans. Comparative Biochemistry and Physiology a-Molecular and Integrative Physiology 119, 845-852.
The firing properties and distribution of the cool-sensitive neurons in the ventral nerve cord were studied in lour crustacean species (Panulirus japonicus, Penaeus japonicus, Homarus americanus and Ligia exotica). Several efferent axons in each of the three nerve roots (r1, r2, r3) initiated impulses or raised frequency of spontaneous impulses when the isolated nerve cord was cooled for 3-5 min. The spontaneous and elicited impulses stopped with warming. The efferent firing pattern was tonic. The increase in impulse frequency depended on falling temperature in a range of 0.5-5.5 degrees C. The response curve to ooling was sigmoid. The maximum frequency of large amplitude impulses was up to 10 Hz, whereas smaller amplitude impulses were higher than 10 Hz. These cool-sensitive neurons appeared present in all ganglia in the nerve cord of the four crustacean species. Most silent neurons in an isolated abdominal ganglion were slowly depolarized by cooling (0.5 mV/degrees C). But this depolarization did not result in spiking. A few silent neurons (3%) produced sustained depolarizing potentials with cooling (2.5-3 mV/degrees C) and generated action potentials. The cold neurons seemed to be interneurons and appeared to interact synaptically with other interneurons and some efferent neurons in the ganglion. Judged from the high sensitivity and the distribution of the cool- sensitive neurons, the central cold neurons of crustaceans may function as an environmental temperature detector. (C) 1998 Elsevier Science Inc.
Taylor, H. H., Paterson, B. D., Wong, R. J., and Wells, R. M. G. (1997). Physiology and live transport of lobsters: report from a workshop. Marine and Freshwater Research 48, 817-822.
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Taylor, H. H., and Waldron, F. M. (1997). Respiratory responses to air-exposure in the southern rock lobster, Jasus edwardsii (Hutton) (Decapoda : Palinuridae). Marine and Freshwater Research 48, 889-897.
Air-exposure of settled Jasus edwardsii at 17 degrees C initially halved oxygen consumption, doubled ventilation frequency and reduced heart rate. During 8 h emersion, oxygen uptake partially recovered, ventilation remained elevated and heart rate was restored. Haemolymph P-CO2 increased fourfold, despite the hyperventilation. Branchial gas exchange, initially impaired In air, may improve as the gills drain. Partial anaerobiosis was indicated by elevation of haemolymph [lactate(-)] to 4.2 mmol L-1. Although haemolymph pH decreased similar to 0.3 units over 8 h, a base excess compensated all of the metabolic and part of the respiratory acidosis. On return to water, oxygen consumption initially increased to >2.5 times pre-emersion rates while ventilation and heart rates increased further. Most respiratory variables returned to pre-emersion levels within 8 h of reimmersion, but oxygen consumption and heart rate remained elevated for 24 h. The excess oxygen consumption over resting rate during 24 h recovery in water indicated a metabolic cost of 8 h emersion equivalent to 10 h resting metabolism in water. These responses contrast with better acid-base compensation previously reported for undisturbed Homarus gammarus in air and worse tolerance of air- exposure by Panulirus argus.
Tazaki, K., and Cooke, I. M. (1986). Currents under voltage clamp of burst-forming neurons of the cardiac ganglion of the lobster (Homarus americanus). J Neurophysiol 56, 1739-62.
Crustacean cardiac ganglion neuronal somata, although incapable of generating action potentials, produce regenerative, slow (greater than 200 ms) depolarizing potentials reaching -20 mV (from -50 mV) in response to depolarizing stimuli. These potentials initiate a burst of action potentials in the axon and are thus termed driver potentials. The somata of the anterior-most neurons (cells 1 or 2) were isolated by ligaturing for study of their membrane currents with a two-electrode voltage clamp. Inward current is attributed to Ca2+ by reason of dependence of driver potential amplitude on [Ca2+]0, independence of [Na+]0, resistance to tetrodotoxin, and inhibition by Cd (0.2 mM) and Mn (4 mM). Ca-mediated current (ICa) is present at -40 mV. It is optimally activated by a holding potential (Vh) of -50 to -60 mV and by clamps (command potential, Vc) to -10 mV. Time to peak (10-30 ms) and amplitude are strongly voltage dependent. Maximum tail-current amplitudes observed at -70 to -85 mV are ca. 100 nA. Inward tail peaks may not be resolved by our clamp (settling time, 2 ms). Tails relax with a time constant (tau) of approximately equal to 12 ms (at -70 to - 85 mV). ICa exhibits inactivation in double pulse regimes. Recovery has a tau of approximately equal to 0.7 s. Tail current analyses indicate an exponential decline (tau approximately equal to 23 ms at -20 mV) toward a maintained amplitude of inward current tails. Analysis of outward currents indicates the presence of three conductance mechanisms having voltage dependences, time courses, and pharmacology similar to those of early outward current (IA), delayed outward current (IK), and outward current (IC) of molluscan neurons. Analysis of tail currents indicates a reversal potential for each of these near -75 mV, indicating that they are K currents. Early outward current, IA, shows a peak at 5 ms followed by rapid decline. Response to a second clamp given within 0.4 s is reduced; recovery is exponential, with a tau of approximately equal to 200 ms (at Vh = -50 mV). The amplitude of IA tested at 0 mV shows activation or deactivation by subthreshold shifts of Vh. The extent and rate of these changes shows voltage dependence (tau approximately equal to 100-500 ms for subthreshold prepulses). At the normal cell resting potential of -50 mV the amplitude of IA is 25% of that tested from -80 mV.(ABSTRACT TRUNCATED AT 400 WORDS).
Tazaki, K., and Cooke, I. M. (1990). Characterization of Ca current underlying burst formation in lobster cardiac ganglion motorneurons. J Neurophysiol 63, 370-84.
1. The anterior motorneurons of the cardiac ganglion of Homarus americanus were ligated less than 300 microns from the soma. This removes impulse-generating membrane and sites of synaptic input while preserving the ability of the soma to generate the burst-forming potentials termed "driver potentials" regenerative, slow (250-ms duration) depolarizations (to -20 mV) in response to brief, depolarizing stimuli. At stimulus intervals corresponding to rates of bursting observed in spontaneously active, intact ganglia (0.3-1.2/s), driver potential amplitude increases with increasing stimulus interval. 2. A two-electrode voltage clamp was used to characterize inward current observable from the ligated neurons in tetrodotoxin (TTX)- tetraethylammonium (TEA)-containing salines. The amplitude of inward current shows a hyperbolic relation to [Ca]o that is well fitted by a form of the Michaelis-Menten equation. Inward current is maintained but not augmented when Ca2+ is replaced by Ba2+ or Sr2+. It is concluded that the inward current, to be referred to as ICa, is mediated by voltage-dependent Ca channels. 3. Contamination of ICa by early outward current (IA) was evaluated by addition of 4-aminopyridine (4-AP, 4 mM). In the presence of 4-AP, the net inward current is increased and the potential at which maximum ICa occurs is shifted 10 mV more positive. 4. Subtraction of outward currents recorded in Mn2(+)-containing saline from overall currents in the absence of Mn2+ provided another means to separate inward from outward current. I-V curves from such "Mn- subtracted" records show ICa approaches a saturating value for steps to -5 mV and more depolarized. The time to peak ICa is voltage dependent. The largest inward currents (up to 240 nA) and minimal time to peak (4 ms) are observed for steps from holding potentials of -50 to -60 mV. 5. Decline of ICa during depolarized steps observed in Mn-subtracted records represents inactivation rather than development of competing outward current. Inactivation is slow and incomplete; the rate and fractional amount of inactivation are not directly voltage dependent. Nonsubtracted responses to 500-ms depolarizations to potentials evoking little outward current show that an initial rapid decline of ICa (tau approximately 40 ms) is followed at approximately 80 ms by a slower phase of decline (tau approximately 180 ms). With repetitive clamps, the early phase proved labile.(ABSTRACT TRUNCATED AT 400 WORDS).
Telford, M. (1968). The effects of stress on blood sugar composition of the lobster, Homarus americanus. Can J Zool 46, 819-26.
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Tensen, C. P., De Kleijn, D. P., and Van Herp, F. (1991). Cloning and sequence analysis of cDNA encoding two crustacean hyperglycemic hormones from the lobster Homarus americanus. Eur J Biochem 200, 103-6.
Using the polymerase chain reaction with degenerated oligonucleotides, we have isolated cDNA clones that encode two structurally different (92% identity) crustacean hyperglycemic hormones (CHH) from the lobster Homarus americanus. The deduced amino acid sequences fully agree with previously published data on partial amino acid sequences, amino acid compositions and molecular masses of hyperglycemic peptides in the lobster. A comparative analysis between the deduced primary structure of two lobster CHH and the crab CHH sequence reveals a phylogenetic relationship and allows the prediction of biologically important regions within the structures of these novel neuropeptides.
Tensen, C. P., Verhoeven, A. H., Gaus, G., Janssen, K. P., Keller, R., and Van Herp, F. (1991). Isolation and amino acid sequence of crustacean hyperglycemic hormone precursor-related peptides. Peptides 12, 673-81.
The crustacean hyperglycemic hormone (CHH) is synthesized as part of a larger preprohormone in which the sequence of CHH is N-terminally flanked by a peptide for which the name CPRP (CHH precursor-related peptide) is proposed. Both CHH and CPRP are present in the sinus gland, the neurohemal organ of neurosecretory cells located in the eyestalk of decapod crustaceans. This paper describes the isolation and sequence analysis of CPRPs isolated from sinus glands of the crab Carcinus maenas, the crayfish Orconectes limosus and the lobster Homarus americanus. The published sequence of "peptide H" isolated from the land crab, Cardisoma carnifex, has now been recognized as a CPRP in this species. Sequence comparison reveals a high level of identity for the N-terminal region (residues 1-13) between all four peptides, while identity in the C-terminal domain is high between lobster and crayfish CPRP on the one hand, and between both crab species on the other. Conserved N-terminal residues include a putative monobasic processing site at position 11, which suggests that CPRP may be a biosynthetic intermediate from which a potentially bioactive decapeptide can be derived.
Tensen, C. P., Janssen, K. P., Soyez, D., and Van Herp, F. (1991). Comparative characterization of hyperglycemic neuropeptides from the lobster Homarus americanus. Peptides 12, 241-9.
With the use of a two-step HPLC purification procedure, two sets of two isoforms of the crustacean hyperglycemic hormone (CHH) were isolated from sinus glands of the lobster Homarus americanus. Structural differences between the two groups of isoforms were found in their amino acid sequences, amino acid compositions and precise molecular weights. Using peptide mapping, the difference between the isoforms in each group was located within the first eight amino acids at the N- termini. The nature of this difference remained unclear as all four peptides had the same N-terminal amino acid sequence unto residue 19.
Thamotharan, M., and Ahearn, G. (1996). Dipeptide transport by crustacean hepatopancreatic brush-border membrane vesicles. J Exp Biol 199, 635-41.
Epithelial brush-border membrane vesicles (BBMVs) of lobster (Homarus americanus) hepatopancreas were formed by a Mg2+ precipitation technique. In these BBMVs, [14C]glycylsarcosine ([14C]Gly-Sar) uptake was stimulated by a transmembrane proton gradient. transmembrane K+ diffusion potential (inside negative) stimulated [14C]Gly-Sar uptake above that observed with short-circuited vesicles, while an inwardly directed Na+ gradient had no stimulatory effect on peptide uptake. [14C]Gly-Sar influx (over 10 s) occurred by a low-affinity, saturable, proton-gradient-dependent carrier system (Kt=5.90±0.13 mmol l-1, Jmax=4662±487 pmol mg-1 protein 10 s-1; mean ± s.e.m., N=3). This carrier exhibited a high-affinity proton binding site (KH=235±25 nmol l-1; pK=6.6) and an apparent 1H+:1Gly-Sar transport stoichiometry. Influx of 0.1 mmol l-1 [14C]Gly-Sar into lobster hepatopancreatic BBMVs was significantly (P0.01) cis-inhibited by 10 mmol l-1 diethylpyrocarbonate and by a variety of other dipeptides (10 mmol l-1), suggesting a broad transport specificity. These observations strongly suggest that transport of peptides into crustacean hepatopancreas is proton-gradient-dependent and electrogenic, qualitatively resembling the peptide transport paradigm proposed for fish and mammals.
Thurn, M. J., and Hall, M. R. (1999). Ovarian function in the giant tiger prawn (Penaeus monodon) as determined by in vitro bioassay. Physiological and Biochemical Zoology 72, 588-596.
Ovary tissue fragments of the giant tiger prawn Penaeus monodon were incubated in vitro with L-methionine[S-35] plus L- cysteine[S-35] as a metabolic labeling reagent. The labeled cytoplasmic and secreted proteins synthesized in vitro during incubations under various conditions were subjected to SDS polyacrylamide electrophoresis and visualized by autoradiography. Vitellogenin (Vg) was immunologically identified and shown to be actively synthesized and released into the incubation medium. The synthesis and release of Vg into the incubation medium was optimized and shown to be linear over a 16-h period. Comparisons between different ovarian regions and different stages of development revealed that the level of Vg synthesis and accumulation in the incubation media was variable depending on stage of development and region within the ovary. Coincubation of ovarian fragments with sinus gland extracts showed a dose-related inhibition of total protein and Vg synthesis. The in vitro ovarian bioassay is suitable for examining the effect of hormonal inputs of P. monodon.
Tierney, A. J., Blanck, J., and Mercier, A. J. (1997). FMRFamide-like peptides in the crayfish (Procambarus clarkii) stomatogastric nervous system: Distribution and effects on the pyloric motor pattern. Journal of Experimental Biology 200, 3221-3233.
Whole-mount immunocytochemistry was used to map the location of FMRFamide-like peptides in the crayfish (Procambarus clarkii) stomatogastric nervous system. This system contains the pyloric and gastric mill central pattern generators, which receive modulatory inputs from projection neurons with somata located primarily in other ganglia of the stomatogastric nervous system, Our studies revealed stained somata in the commissural and esophageal ganglia. A pair of stained somata was located in the inferior ventricular nerve, and another pair of somata was located in the stomatogastric nerve where it is joined by the two superior esophageal nerves, The stomatogastric ganglion contained no stained somata, but the neuropil was brightly stained and 2-4 axons projected laterally in small nerves directly from the ganglion. These results indicate that FMRFamide or related peptides may act as neuromodulators in the crayfish stomatogastric nervous system. To test this hypothesis, we studied the effects of FMRFamide and four related peptides (DF2, NF1, F-1 and LMS) on the pyloric motor pattern, DF2, NF1 and F-1 all excited certain pyloric cells, especially the lateral pyloric (LP) and ventricular dilator (VD) neurons, and enhanced pyloric cycling frequency in most actively rhythmic preparations, FMRFamide had no detectable effects on pyloric cells, and LMS had inhibitory effects, causing disruption of the pyloric rhythm in actively cycling preparations and reducing tonic activity in non-rhythmic preparations.
Tierney, A. J., Godleski, M. S., and Rattananont, P. (1999). Serotonin-like immunoreactivity in the stomatogastric nervous systems of crayfishes from four genera. Cell and Tissue Research 295, 537-551.
We used whole-mount immunocytochemistry to characterize the distribution of serotonin in the stomatogastric nervous systems of seven species of crayfish representing three genera from the family Cambaridae (Orconectes, Cambarus, and Procambarus) and one from the family Astacidae (Pacifastacus). In all species, we observed serotonin-like immunoreactivity in four gastropyloric receptor (GPR) neurons located in the lateral ventricular nerves, with one pair of neurons in each nerve. As in other crustaceans, the GPR axons project to the stomatogastric ganglion and to the bilateral commissural ganglia. In three cray fishes, we observed the GPR axons crossing the commissural ganglia and extending toward the thoracic nervous system. This feature was most clearly and consistently seen in Pacifastacus leniusculus. The number of stained somata in the commissural ganglia varied among crayfish species from two (in Procambarus clarkii) to five (in Pacifastacus leniusculus). The largest soma (the L cell) displayed both serotonin- and tyrosine hydroxylase-like immunoreactivity in all species, suggesting that serotonin and dopamine are cotransmitters in this cell. The inferior esophageal nerve and a branch of this nerve (the inner labral nerve) contained several axons with serotonin-like immunoreactivity. These axons were clearly present in only one species (Procambarus us clarkii). Serotonin acts as a neuromodulator of rhythms produced by circuits in the crab and lobster stomatogastric ganglion, and is likely to play a similar role in crayfish. Differences are apparent in the distribution of serotonin among crayfish species and between crayfish and other crustaceans, and could result in differences in the physiological action of this modulator.
Tremblay, M. J., and Eagles, M. D. (1997). Molt timing and growth of the lobster, Homarus americanus, off northeastern Cape Breton Island, Nova Scotia. Journal of Shellfish Research 16, 383-394.
Seasonal changes in molt condition, together with mark- recapture data, were used to estimate molt timing and growth of adolescent and adult lobsters (Homalus americanus) in the St. Anns Bay area (northeastern Cape Breton Island) in 1993 and 1994. In both years, most molting occurred between late Jul:, and early September. Within the larger sizes (>70 mm CL), males molted earlier than females, but there was extensive overlap in their molting periods. Annual differences in molting time were apparent and were linked to bottom temperature. Double moiling of individual lobsters was rare and limited mainly to prerecruit lobsters. From spring to autumn, there were substantial changes in trap catch rate, size composition. and sex ratio. Males dominated the catch in late summer and fall, probably because they molted earlier than females. Within- season and between-year changes in catchability associated with molting need accounting if trap catch rates are to be used as indices of lobster abundance and for estimation of exploitation rate.
Trimmer, B. A., Kobierski, L. A., and Kravitz, E. A. (1987). Purification and characterization of FMRFamidelike immunoreactive substances from the lobster nervous system: isolation and sequence analysis of two closely related peptides. J Comp Neurol 266, 16-26.
In the preceding paper (Kobierski et al: J. Comp. Neurol. 266:1-15, '87) FMRFamidelike immunoreactivity (FLI) was localized to specific cells and processes in the nervous system of the lobster Homarus americanus. In an effort to establish a role for this material we have purified and characterized a variety of immunoreactive peptides that can be extracted from the secretory pericardial organs. By using gel- filtration chromatography and three different HPLC systems, it has been established that little or no authentic FMRFamide is present. Of the major immunoreactive components two peptides were purified in sufficient quantity for microsequence analysis and have been tentatively identified as the octapeptides Ser-Asp-Arg-Asn-Phe-Leu-Arg- Phe-amide (FLI 3) and Thr-Asn-Arg-Asn-Phe-Leu-Arg-Phe-amide (FLI 4). Both of these are novel neuropeptides with some sequence homology to the previously described FMRFamide family. The pericardial organs release FLI when depolarized with 100 mM K+ in the presence of calcium. Between 75 and 80% of this release is accounted for by FLI 3 and FLI 4. One of these peptides (FLI 4) has been synthesized and shown to cochromatograph with the endogenous immunoreactive material. Preliminary studies show that this peptide can act as a modulator of exoskeletal and cardiac neuromuscular junctions.
Trippel, E. A. (1999). The first marine biological station in Canada: 100 years of scientific research at St. Andrews. Canadian Journal of Fisheries and Aquatic Sciences 56, 2495-2507.
The first marine biological station in Canada was established in St. Andrews, New Brunswick, in July 1899. The original station was a portable laboratory and was moved between various summer research sites in Atlantic Canada before a permanent station was established in St. Andrews in 1908. Early research included practical problems in the fisheries and descriptive work of coastal fauna and was performed by university researchers. Contributions to Canadian Biology, a journal founded to report the findings of the early station's researchers, in time evolved into the Canadian Journal of Fisheries and Aquatic Sciences. For the first 75 years, the station was managed as part of the Fisheries Research Board of Canada and its predecessors, and since 1979 by the Department of Fisheries and Oceans (from 1972 to 1978, two other government departments held this responsibility). Research on fisheries, the environment, oceanography, and aquaculture has dominated the station's history. July 1999 marked the 100th anniversary of marine research in St. Andrews. We celebrate and remember with pride our accomplishments and look forward to the future of conserving Canada's aquatic environment and the livelihood of Atlantic Canadians.
Trott, T. J., Voigt, R., and Atema, J. (1997). Chemoreception by the red-jointed fiddler crab Uca minax (LeConte): Spectral tuning properties of the walking legs. Marine and Freshwater Behaviour and Physiology 30, 239-249.
The red-jointed fiddler crab Uca minax is one of the most abundant macroinvertebrates inhabiting the temperate western Atlantic salt marshes, along the eastern and southern coasts of the United States. Dactyl chemoreception is the primary sensory modality involved in food detection. Ninety-six chemoreceptor cells from 69 male and female second and third legs were tested with 20 compounds known to be stimulatory in other decapods. Each compound was tested as 1 s pulses at 10(-3) M. Overall, chemoreceptor cells on the dactyls responded strongest to glutamate and ammonium chloride followed by citric acid. Glutamate-and ammonium chloride-best cells formed the most prominent cell populations and were relatively narrowly tuned. Individual cells exhibited a range of tuning breadths based on responses to single compounds. Amines were moderately stimulatory. Surprisingly, hexose sugars which cause strong behavioural responses in U. minax elicited only weak physiological responses. Glutamate sensitivity separates U. minax from other species of fiddler crabs. The results indicate that the chemical response spectrum of U. minax includes compounds that occur naturally in salt marshes as algal and animal constituents, exudates, and decomposition products.
Trott, T. J. (1999). Gustatory responses of ghost crab Ocypode quadrata to seawater extracts and chemical fractions of natural stimuli. Journal of Chemical Ecology 25, 375-388.
The efficacy of seawater-extracted fresh and decomposing blue crab (Callinectes sapidus) claw muscle homogenates as stimulants of feeding behavior by the ghost crab (Ocypode quadrata) was tested with cheliped flexion as a bioassay. Stimulatory components of extracts were heat-stable and <1 kDa. Fresh seawater extracts of muscle tissue homogenate elicited the most responses and decreased in efficacy with decomposition. Ultrafiltrates <1 kDa also became less stimulating with increasing decay of the homogenate. When ultrafiltrates were extracted with ethyl ether, the aqueous phase elicited the most responses. To some degree, active components were soluble in ether. Ion-exchange chromatography of the aqueous phase yielded eluates containing neutral and acidic compounds, which, following a peak in activity, became less stimulatory over time. In contrast, eluates containing amphoteric and basic compounds remained highly effective throughout bacterial degradation. However, their activity was significantly suppressed when they were mixed with neutral and acidic compounds isolated from the same samples. Mixture suppression may function as a mechanism ensuring the consumption of high-quality foods. The ability of O. quadrata to respond to both fresh and decomposing tissues contributes to this species' flexibility in foraging strategies and its success as an inhabitant of sandy beaches.
Tsai, K. L., and Talbot, P. (1993). Video microscopic analysis of ionophore induced acrosome reactions of lobster (Homarus americanus) sperm. Mol Reprod Dev 36, 454-61.
Sperm from the American lobster (Homarus americanus) are normally nonmotile. However, during fertilization, the sperm undergo a calcium- dependent acrosome reaction that propels them forward about 18 microns. The reaction occurs in two phases, eversion and ejection, which take place too quickly to permit analysis by direct observation. The purposes of this study were to examine the structural changes occurring in sperm during the normal acrosome reaction and to determine the rate of the reaction using video microscopy. The reaction was induced in vitro by ionophore A23187 and recorded using a video system attached to a Nikon Nomarski interference microscope. Videotapes were played back frame by frame (30 frames/sec), and images of reactions from 10 sperm were analyzed. The acrosome reaction, including the eversion of the acrosomal vesicle and ejection of the subacrosomal material and nucleus, can be divided into 4 steps: (1) expansion of the apical cap followed by expansion of the remainder of the acrosomal cylinder; expansion of the cylinder begins at its apical end and proceeds toward its base, (2) eversion of the apical half of the acrosomal vesicle and initial contraction of the apical cap, (3) eversion of the basal half of the acrosomal vesicle, continued contraction of the apical cap, and ejection of the subacrosomal material and nucleus, and (4) final contraction of the apical cap and ejection of the acrosomal filament. During steps 2, 3, and 4, the mean forward movement of sperm is 12.7, 3.9, and 1.1 microns, respectively.(ABSTRACT TRUNCATED AT 250 WORDS).
Tshudy, D., and Parsons, G. A. (1998). Intraspecific variation in external morphology of the American lobster, Homarus americanus (Crustacea : Decapoda : Nephropidae). Proceedings of the Biological Society of Washington 111, 102-109.
Intraspecific variation in external morphology of Homarus americanus H. Milne Edwards was examined in order to interpret better the fossil record of clawed lobsters. Several hundred H. americanus were collected from the Gulf of Maine. Lobsters were collected from rocky, shelly and muddy substrates. Detailed examination of 175 specimens indicates that carapace proportions, carapace groove positions, expression of carapace spines and general claw form are virtually constant within the sample-regardless of age, sex or substrate. This corroborates the scarcely published conclusion of taxonomists on modern lobsters: these external features are, in fact, reliable species characters. This study also shows, however, that number and arrangement of spines on the rostrum and claws are variable within the species and, therefore, not good species characters; this variation is unrelated to age, sex or substratum.
Tsukimura, B., and Borst, D. W. (1992). Regulation of methyl farnesoate in the hemolymph and mandibular organ of the lobster, Homarus americanus. Gen Comp Endocrinol 86, 297-303.
Methyl farnesoate (MF) was measured in the hemolymph and mandibular organs (MO) of the lobster. Although a few animals had detectable MF levels in their hemolymph, this compound was undetectable (less than 0.4 ng/ml) in the hemolymph of most animals. One day after bilateral eyestalk ablation, MF was detected in the hemolymph of all animals, reaching variable levels (2.0-31.2 ng/ml) by the fourth day. Unilateral eyestalk ablation caused a smaller increase in hemolymph levels of MF. Similarly, the MF content of the MO, the only known site of MF synthesis, was low in intact lobsters (8.1 ng/gland) and was elevated in unilaterally and bilaterally eyestalk-ablated animals (54.1 and 106.9 ng/gland, respectively). When extracts of the sinus gland (SG), a source of neuropeptides in the eyestalk, were injected into bilaterally ablated lobsters, hemolymph levels of MF dropped to undetectable levels in 2 to 3 hr. The response to SG extract was dose dependent, and MF levels recovered by 12 to 24 hr after treatment. SG extract also lowered the MF content in the MO from 267.6 to 6.6 ng/gland after 4 hr. These results indicate that MF in the hemolymph and MO is negatively regulated by a factor(s) from the SG.
Tucker, R. K. (1979). Effects of in vivo cadmium exposure on ATPases in gill of the lobster, Homarus americanus. Bull Environ Contam Toxicol 23, 33-5.
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Tudge, C. C., Scheltinga, D. M., and Jamieson, B. G. M. (1998). Spermatozoal ultrastructure in the spiny lobster Jasus novaehollandiae Holthuis, 1963 (Palinuridae, Palinura, Decapoda). Journal of Morphology 236, 117-126.
The spermatozoal ultrastructure of the spiny lobster Jasus novaehollandiae is most similar to that in other investigated palinurans and, in particular, to the spermatozoa of Parulirus species. Shared characters include the globular nucleus penetrated by the bases of three or more microtubular arms; an anteriorly situated cytoplasmic zone with mitochondria and conspicuous lamellar bodies; a complex, four-zoned acrosomal vesicle (however, lacking the crystalline region present in Panulirus) with a homogeneous region; a scroll region; a flocculent region; and a region of periacrosomal material that farms finger-like involutions into the flocculent region. The related scyllarid slipper lobsters (Scyllarus and Thenus) possess spermatozoa with acrosome morphology similar to that of Jasus, but the sperm is generally more flattened, numerous radiating acrosome fins are present, and the microtubular arms (in Scyllarus) are cytoplasmic in origin and not nuclear. Sperm morphology provides preliminary evidence in support of the hypothesis of two independent lines of evolution in the Palinuridae but investigation into additional taxa within this group is required.
Turrigiano, G. G., and Selverston, A. I. (1991). Distribution of cholecystokinin-like immunoreactivity within the stomatogastric nervous systems of four species of decapod crustacea. J Comp Neurol 305, 164-76.
The distribution of cholecystokinin-like immunoreactivity was studied in the stomatogastric nervous systems, pericardial organs, and haemolymph of four species of decapod crustacea, by using immunocytochemical and radioimmunoassay techniques. Whereas cholecystokinin-like immunoreactivity was found within the stomatogastric nervous systems of all four species, its distribution in each is unique. Two species (Panulirus interruptus and Homarus americanus) have cholecystokinin-like immunoreactivity within fibers and neuropil of the stomatogastric ganglion (STG); two other species (Cancer antenarius and Procambarus clarkii) do not. Further, the cholecystokinin-like immunoreactivity within the STGs of Panulirus and Homarus arise from distinct structures; from a projection of anterior ganglia in Panulirus, and from somata within the posterior motor nerves in Homarus. The staining in the other ganglia of the stomatogastric nervous system also shows some interspecies variability, although it appears to be more highly conserved than staining within the STG. These differences in staining were confirmed by measuring the amount of CCK- like peptide present in tissue extracts of ganglia by radioimmunoassay. In contrast to the variable staining within the STG, all four species have cholecystokinin-like immunoreactivity within the neurosecretory pericardial organs and thoracic segmental nerves. This cholecystokinin- like immunoreactivity is contained within fibers and within varicosities that coat the surface of these structures. The location of this staining and the presence of detectible levels of CCK-like peptide in the haemolymph suggests that CCK-like peptides in decapod crustacea may be utilized as neurohormones.
Umphrey, H. R., Lee, K. J., Watson, R. D., and Spaziani, E. (1998). Molecular cloning of a cDNA encoding molt-inhibiting hormone of the crab, Cancer magister. Molecular and Cellular Endocrinology 136, 145-149.
A neuropeptide molt-inhibiting hormone (MIH) negatively regulates crustacean molting glands (Y-organs). We report here the molecular cloning of a cDNA encoding putative MIH of the Dungeness crab, Cancer magister. A cDNA library was commercially prepared using poly (A(+)) RNA isolated from C. magister eyestalk neural ganglia. The library was screened using as probe a previously cloned portion of a cDNA encoding MIH of the blue crab, Callinectes sapidus. DNA sequence analysis of one positive clone revealed a 339 base pair open reading frame encoding a 78 amino acid putative MIH and a 35 amino acid signal peptide. The deduced amino acid sequence of C. magister MIH shows high sequence identity (80-98%) with MIH of three other brachyuran crabs, but lower identity (26-45%) with MIH and MIH-like peptides from astacurans and shrimp. Studies using reverse transcription-polymerase chain reaction (RT-PCR) indicate the MIH gene is expressed in eyestalk but not control (muscle, gill, gonad, hepatopancreas) tissue. (C) 1998 Elsevier Science Ireland Ltd.
Uthe, J. F., and Musial, C. J. (1986). Polycyclic aromatic hydrocarbon contamination of American lobster, Homarus americanus, in the proximity of a coal-coking plant. Bull Environ Contam Toxicol 37, 730-8.
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Uthe, J. F., Scott, D. P., and Chou, C. L. (1987). Cadmium contamination in American lobster, Homarus americanus, near a coastal lead smelter: use of multiple linear regression for management. Bull Environ Contam Toxicol 38, 687-94.
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Uthe, J. F., Misra, R. K., King, T. L., and Musial, C. J. (1996). Estimating analytical variances in measurement of polycyclic aromatic hydrocarbons and application to monitoring contaminants in American lobster (Homarus americanus). J AOAC Int 79, 797-802.
A method is presented for estimating replicate polycyclic aromatic hydrocarbon (PAH) concentrations in American lobster (Homarus americanus) digestive gland tissue based on recoveries of added perdeuterated surrogates from a single satisfactory analysis. PAH concentrations demonstrated a large interanimal variance, even in specimens captured at the same time in the same place. Principal component analysis showed that the variability of the total system of biological variables (carapace length, lobster weight, and digestive gland weight) could be adequately summarized by the first principal component alone in each data set. Ranks provide ordered classification of individuals, allowing data analysis by statistical methods for continuous variables (i.e., analysis of variance). PAH concentrations in individual lobsters were generally highly sensitive to animal size, sex, and fishing area. Efficient monitoring would result from analyzing individual animals of a single sex from a study area, using as small a geographical study area as possible, measuring a single biological variable, and using individual specimens of as narrow a size range as possible.
Utting, M., Agricola, H. J., Sandeman, R., and Sandeman, D. (2000). Central complex in the brain of crayfish and its possible homology with that of insects. Journal of Comparative Neurology 416, 245-261.
A small, medial heterolateral neuropil in the brain of crustaceans has long been regarded as the central body of the crustacean brain. Its simplicity and the absence of clear layers within its neuropil have led to the question of its homology with the more complex central body that occupies an approximately equivalent position in the brain of insects. We have labelled neurons in the central body of the Australian freshwater crayfish Cherax destructor by the extracellular application of dextrans and by treating the brain with antibodies to anti-CCAP, anti-locustatachykinin, anti- perisulfakinin,anti-proctolin, anti-dip-allatostatin AI, anti- PEA-head-peptide, anti-serotonin, and anti-rabbit anti- substance P, all of which label neurons in the insect brain. The dextran and immunocytochemical labelling have revealed a neural complex associated with the crayfish central body that is very similar in overall anatomical architecture to the subset of neuropils that are incorporated in the central complex of the insects, and in particular to that of the locust. Similarities between the crayfish and locust central complexes extend to the number and position of the neuropils, the location of the cell body clusters of the neurons that belong to the central complex, the numbers of tracts that link some of the constituent neuropils together, and the form and immunoreactivity of many of the individual neuron classes. These similarities are taken as evidence to support a possible homology between the crustacean central complex and that of the insects. J. Comp. Neurol. 416:245-261, 2000. (C) 2000 Wiley- Liss, Inc.
Uzmann, J. R. (1967). Juvenile Ascarophis (Nematoda: Spiruroidea) in the American lobster, Homarus americanus. J Parasitol 53, 218.
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Uzmann, J. R. (1967). Historiobdella homari (Annelida: Polychaeta) in the American lobster, Homarus americanus. J Parasitol 53, 210-1.
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van der Meeren, G. I. (1997). Preliminary acoustic tracking of native and transplanted European lobsters (Homarus gammarus) in an open sea lagoon. Marine and Freshwater Research 48, 915-921.
In a larger release project, European lobsters (Homarus gammarus) under legal size have been captured, checked for magnetic microtags, externally tagged, and released to their home site for population and migration studies. To see if transplanted lobsters behave differently from native lobsters, four acoustically tagged males were released between three stationary hydrophones in an open sea lagoon and tracked continuously for 2-3 weeks. Lobster 1 was from the lagoon, Lobster 2 was transplanted less than 1000 m from its capture location, and Lobsters 3 and 4 were transplanted more than 5000 m. Within a few hours, Lobsters 1 and 2 took up residence in the area of their original home sites. Lobsters 3 and 4 took up residence in the lagoon after extended roaming. Six days after release, Lobsters 1 and 4 engaged in nocturnal activity, Lobster 2 changed locations occasionally without moving long distances, and Lobster 3 did not move. The odd movement patterns in the transplanted lobsters could be caused by their lack of local knowledge. Since rocks caused blocking of the acoustic signals, manual monitoring was needed to confirm the lobster positions. In cryptic animals such as lobsters, a continuous tracking system that can penetrate stones is required.
Voigt, R., Weinstein, A. M., and Atema, J. (1997). Spectral tuning of chemoreceptor cells in the lateral antennules of the American lobster, Homarus americanus. Marine and Freshwater Behaviour and Physiology 30, 19-27.
Chemoreceptor cells in the lateral flagellum of the first antennae (lateral antennule) of the American lobster, Homarus americanus, serve, among other functions, in long distance orientation and mediate chemical recognition of food and chemical information used in social interactions. Based upon extracellular recordings of action potentials, we report on 60 cells identified with a 15-compound equimolar mixture of mostly amino acids and a few other compounds used in previous studies of lobster chemoreceptors. Subsequently, all cells were tested with each compound separately. Forty-three percent of all cells responded strongest to hydroxyproline, 13% to taurine, and 10% to glutamate. These cells were generally narrowly tuned and had no consistent second best stimulus. Other cells were more broadly tuned and responded strongest to valine, arginine, leucine, glutamine, serine, glycine, alanine and ammonium. Most chemoreceptor cells responded less to a mixture containing their best compound than to the best compound alone, though a few gave stronger responses to the mixture. At a low concentration (10(-6) M) the mixture components enhanced the response to Hydroxyproline (Hyp); at medium and higher concentrations (10(-5) M, 10(-4) M) they suppressed the response to Hyp, resulting in a shallow, extended range of the stimulus-response function for the mixture.
Voss, D., and Voigt, R. (1997). Can the female American lobster predict the dominant male? Biological Bulletin 193, 216-217.
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Vye, C., Cobb, J. S., Bradley, T., Gabbay, J., Genizi, A., and Karplus, I. (1997). Predicting the winning or losing of symmetrical contests in the American lobster Homarus americanus (Milne-Edwards). Journal of Experimental Marine Biology and Ecology 217, 19-29.
The ability to predict the outcome of symmetrical contests between male lobsters (Homarus americanus) on the basis of 21 variables was investigated using a stepwise discriminant analysis. Measured variables included wet weight, carapace length, claw length, width and thickness, claw volume, claw contraction force, handedness, antenna length, color, plasma protein level, plasma calcium level, exoskeleton calcium concentration and motor activity. Plasma protein level, exoskeleton calcium concentration and claw dimensions were found to be important in the above ascending order for discrimination with an average squared canonical correlation of 0.55-0.65. The discussion focuses on the variables differentiating winners from losers and whether these variables could also aid competing lobsters when assessing the relative fighting ability of their rivals. (C) 1997 Elsevier Science B.V.
Waddy, S. L., and Aiken, D. E. (1999). Timing of the metamorphic molt of the American lobster (Homarus americanus) is governed by a population-based, photoperiodically entrained daily rhythm. Canadian Journal of Fisheries and Aquatic Sciences 56, 2324-2330.
The metamorphic molt of the American lobster (Homarus americanus) occurs in the form of a population-based, recurring daily rhythm that is photoperiodically entrained. Molting occurs predominantly in the scotophase (dark period) at temperatures of 11, 15, and 20.C and in both normal and reversed photoperiod cycles. Molting is arrhythmic in larvae reared in continuous illumination (LL), but when larvae reared in LL are transferred to cyclic photoperiod conditions (LD 12:12), the rhythm is reinstated in a stepwise manner over 3 days. When larvae are transferred from LD 12:12 to LL, the molting rhythm continues for 3 days before dampening. The rhythm appears to be phase-set by the onset of darkness: similar proportions of larvae (79-89%) reared in scotophase lengths of 6, 10, and 12 h molted in the 12-h period following lights-off. The results demonstrate that the synchrony of the metamorphic molt with the scotophase is not fortuitous and suggest that the molting rhythm may result from a gated event under the influence of an endogenous pacemaker.
Wahle, R. A. (1997). Consequences of fishing, with regard to lobster fisheries: report from a workshop. Marine and Freshwater Research 48, 1115-1119.
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Wahle, R. A., and Incze, L. S. (1997). Pre- and post-settlement processes in recruitment of the American lobster. Journal of Experimental Marine Biology and Ecology 217, 179-207.
In censuses conducted between 1989 and 1993 the cause of consistent local differences in benthic recruitment of the American lobster (Homarus americanus Milne-Edwards) to coastal sites in Maine was unclear. Field experiments were conducted to assess the role of pre-and post-settlement processes in causing high and low extremes in recruitment on opposite sides of an outer coastal island in our study area. The west side of the island has some of the highest population densities measured in New England. Our results indicate that postlarval supply determines these differences in recruitment between the two sites. Standardized replicate cobble plots deployed on each side of the island ruled out habitat differences as an explanation for these differences, because they exhibited the same east-west difference in recruitment as the natural habitat. We also ruled out differing rates of post-settlement loss because we recovered previously marked and released settlers in equal numbers in similar plots from both sites. The distribution of neustonic postlarvae and hydrographic evidence indicate that wind-driven surface transport produces an asymmetric postlarval supply to the two sides of the island during the settlement season. Differences in the degree of asymmetry from year to year correspond to differences in the magnitude of eastward transport. We also conducted experiments at the site receiving high recruitment to assess whether new recruits or older year classes were near the saturation of cobble habitat for these animals. The combination of saturation seeding trials, using hatchery-reared lobsters, and weekly counts of natural recruits and immigrants suggests that lobsters may become increasingly subject to crowding as they grow. Movements away from the initial settlement site, probably in part caused by crowding, tend to smooth the inequality in population density which is set initially by postlarval supply. (C) 1997 Elsevier Science B.V.
Walrond, J. P., Wiens, T. J., and Govind, C. K. (1990). Inhibitory innervation of a lobster muscle. Cell Tissue Res 260, 421-9.
Inhibitory neuromuscular synapses formed by the common inhibitor (CI) neuron on the distal accessory flexor muscle (DAFM) in the lobster, Homarus americanus, were studied with electrophysiological and electron- microscopic (thin-section and freeze-fracture) techniques. Postsynaptic inhibition as indicated by inhibitory junctional potentials was several- fold stronger on distal compared to proximal muscle fibers. This difference correlated with the results of serial thin-section studies, which showed more inhibitory synapses on distal fibers than on their proximal counterparts. Effects of postsynaptic inhibition on excitatory junctional potentials via current shunting had a morphological correlate in the spatial relationship between inhibitory and excitatory synapses on the distal fibers. Inhibitory synapses were larger than their excitatory counterparts and had fewer glial processes. In freeze- fracture views, inhibitory synapses did not appear as raised plateaus in the P-face as do excitatory synapses, and their active zones were more widely scattered. The intramembrane particles in the inhibitory postsynaptic membrane - representing neurotransmitter receptors - are arranged in parallel rows in the sarcolemmal P-face and have complementary furrows in the sarcolemmal E-face. Altogether, our findings help to describe a population of inhibitory neuromuscular synapses formed by the CI neuron in lobster muscle.
Walrond, J. P., Govind, C. K., and Huestis, S. E. (1993). Two structural adaptations for regulating transmitter release at lobster neuromuscular synapses. J Neurosci 13, 4831-45.
The distal accessory flexor muscle (DAFM) in the lobster (Homarus americanus) walking leg consists of 5 muscle fiber bundles. All five bundles, one proximal, one distal, and 3 medial, are innervated by one excitatory and one inhibitory motor neuron. Both neurons release more transmitter on the distal bundle than on the proximal bundle. The aim of our studies was to investigate the structural basis of this differentiation. Thin sections cut at 50 microns intervals showed a similar number of excitatory synapses on the two bundles. Freeze- fracture views of excitatory synapses showed that synapse size, active zone number per synapse, and intramembrane particle density in the postsynaptic membrane are similar proximally and distally. Active zones at synapses on the distal bundle are larger and contain about 50% more large intramembrane particles, which are thought to include the voltage- gated Ca2+ channels that couple the action potential to transmitter release, than their counterparts on the most proximal bundle. This difference in channel number appears to produce a disproportionate increase in the probability of transmitter release sufficient to account for most of the proximal-distal disparity in the amplitude of the excitatory postsynaptic potential. In contrast, staining the inhibitor for antibodies to the inhibitory neurotransmitter, GABA, showed that it forms more varicosities on the distal bundle than on the proximal bundle. Because most of the synapses are located in the varicosities, differences in synapse number likely regulate the proximal-distal disparity in the amount of inhibitory transmitter released. Therefore, the regional differentiation in the amount of transmitter released in the DAFM appears to be based on two distinct mechanisms. In the inhibitor, transmitter release appears to be regulated differentially by differences in synapse number. In the excitor, transmitter release appears to be regulated differentially from a similar number of synapses by differences in active zone structure.
Watson, W. H., Vetrovs, A., and Howell, W. H. (1999). Lobster movements in an estuary. Marine Biology 134, 65-75.
The extent to which the American lobster, Homarus americanus (H. Milne-Edwards), utilizes estuarine habitats is poorly understood. From 1989 to 1991 we examined lobster movements in and around the Great Bay estuary, New Hampshire using tag/recapture and ultrasonic telemetry. A total of 1212 lobsters were tagged and recaptured at sites ranging from the middle of Great Bay, 23.0 km from the coast, to Isles of Shoals, 11.2 km offshore. Twenty-six lobsters equipped with ultrasonic transmitters were tracked for periods ranging from 2 weeks to >1 year. Most lobsters moved < 5 km toward the coast, with those furthest inland moving the greatest distance. Lobsters with transmitters moved in a sporadic fashion, with residency in one area for 2 to 4 weeks alternating with rapid movement to a new location (mean velocity = 0.3 km d(-1), 1.8 km d(-1) max.). Site of release influenced distance moved, but there was no significant relationship between lobster size and distance traveled, days at large, or rate of movement. Most movement into the estuary occurred in the spring, while during the remainder of the year there was a strong tendency to move downriver, toward the coast. These seasonal migrations of estuarine lobsters may enhance their growth and survival by enabling them to avoid low salinity events in the spring and fall, and to accelerate their growth in warmer estuarine waters during the summer.
Weesie, R. J., Askin, D., Jansen, F. J., de Groot, H. J., Lugtenburg, J., and Britton, G. (1995). Protein-chromophore interactions in alpha-crustacyanin, the major blue carotenoprotein from the carapace of the lobster, Homarus gammarus. A study by 13C magic angle spinning NMR. FEBS Lett 362, 34-8.
MAS (magic angle spinning) 13C NMR has been used to study protein- chromophore interactions in alpha-crustacyanin, the blue astaxanthin- binding carotenoprotein of the lobster, Homarus gammarus, reconstituted with astaxanthins labelled with 13C at the 14,14' or 15,15' positions. Two signals are seen for alpha-crustacyanin containing [14,14'- 13C2]astaxanthin, shifted 6.9 and 4.0 ppm downfield from the 134.1 ppm signal of uncomplexed astaxanthin in the solid state. With alpha- crustacyanin containing [15,15'-13C2]astaxanthin, one essentially unshifted broad signal is seen. Hence binding to the protein causes a decrease in electronic charge density, providing the first experimental evidence that a charge redistribution mechanism contributes to the bathochromic shift of the astaxanthin in alpha-crustacyanin, in agreement with inferences based on resonance Raman data [Salares, et al. (1979) Biochim. Biophys. Acta 576, 176-191]. The splitting of the 14 and 14' signals provides evidence for asymmetric binding of each astaxanthin molecule by the protein.
Weesie, R. J., Verel, R., Jansen, F., Britton, G., Lugtenburg, J., and deGroot, H. J. M. (1997). The mechanism of the colour shift of astaxanthin in alpha- crustacyanin as investigated by C-13 MAS NMR and specific isotope enrichment. Pure and Applied Chemistry 69, 2085-2090.
By selective isotope enrichment of astaxanthin, MAS NMR and semi-empirical modelling, ligand-protein interactions associated with the red shift in alpha-crustacyanin, the major blue astaxanthin binding carotenoprotein complex from the carapace of the lobster Homarus gammarus, have been analysed. C-13 Magic Angle Spinning (MAS) NMR spectra were obtained after reconstitution with astaxanthins labelled in the centre of the molecule or at the two keto groups. The MAS data reveal electrostatic polarizations of the conjugated chain. In addition, solid state NMR results for pure unlabelled astaxanthin can be compared with natural abundance C-13 MAS data for canthaxanthin and beta-carotene, to address the effect of the ring functionalities on the electronic properties of the polyene chain. Quantum chemical calculations were performed to reconcile the MAS data with one of several simple and straightforward mechanisms for the colour shift. The results point towards a colour shift mechanism in which the astaxanthin may be doubly charged, possibly by a double protonation of the two ring keto groups.
Weesie, R. J., Jansen, F., Merlin, J. C., Lugtenburg, J., Britton, G., and deGroot, H. J. M. (1997). C-13 magic angle spinning NMR analysis and quantum chemical modeling of the bathochromic shift of astaxanthin in alpha- crustacyanin, the blue carotenoprotein complex in the carapace of the lobster Homarus gammarus. Biochemistry 36, 7288-7296.
Selective isotope enrichment, C-13 magic angle spinning (MAS) NMR, and semiempirical quantum chemical modeling, have been used to analyze ligand-protein interactions associated with the bathochromic shift of astaxanthin in alpha-crustacyanin, the blue carotenoprotein complex from the carapace of the lobster Homarus gammarus. Spectra of alpha-crustacyanin were obtained after reconstitution with astaxanthins labeled with C-13 at positions 4,4', 12,12', 13,13', or 20,20'. The data reveal substantial downfield shifts of 4.9 and 7.0 ppm at positions 12 and 12' in the complex, respectively. In contrast, at the 13 and 13' positions, small upfield shifts of 1.9 ppm were observed upon binding to the protein. These data are in line with previously obtained results for positions 14,14' (3.9 and 6.8 ppm downfield) and 15,15' (0.6 ppm upfield) and confirm the unequal perturbation of both halves after binding of the chromophore. However, these results also show that the main perturbation is of symmetrical origin, since the chemical shift differences exhibit a similar pattern in both halves of the astaxanthin molecule. A small downfield shift of 2.4 ppm was detected for the 4 and 4' positions. Finally, the 20,20' methyl groups are shifted 0.4 ppm upfield by the protein. The full data set provides convincing evidence that charge polarization is of importance for the bathochromic shift. The NMR shifts are compared with calculated charge densities for astaxanthin subjected to variations in protonation states of the ring- functional groups, as models of ligand-protein interactions. Taking into account the color shift and other available optical data, the current model for the mechanisms of interaction with the protein was refined. The results point toward a mechanism in which the astaxanthin is charged and subject to strong electrostatic polarizations originating from both keto groups, mast likely a double protonation.
Weesie, R. J., Merlin, J. C., De Groot, H. J. M., Britton, G., Lugtenburg, J., Jansen, F., and Cornard, J. P. (1999). Resonance Raman spectroscopy and quantum chemical modeling studies of protein-astaxanthin interactions in alpha- crustacyanin (major blue carotenoprotein complex in carapace of lobster, Homarus gammarus). Biospectroscopy 5, 358-370.
Resonance Raman spectroscopy and quantum chemical calculations were used to investigate the molecular origin of the large redshift assumed by the electronic absorption spectrum of astaxanthin in alpha-crustacyanin, the major blue carotenoprotein from the carapace of the lobster, Homarus gammarus. Resonance Raman spectra of alpha-crustacyanin reconstituted with specifically C-13-labeled astaxanthins at the positions 15, 15,15', 14,14', 13,13', 12,12', or 20,20' were recorded. This approach enabled us to obtain information about the effect of the ligand-protein interactions an the geometry of the astaxanthin chromophore in the ground electronic state. The magnitude of the downshifts of the C=C stretching modes for each labeled compound indicate that the main perturbation on the central part of the polyene chain is not homogeneous. In addition, changes in the 1250-1400 cm(-1) spectral range indicate that the geometry of the astaxanthin polyene chain is moderately changed upon binding to the protein. Semiempirical quantum chemical modeling studies (Austin method 1) show that the geometry change cannot be solely responsible for the bathochromic shift from 480 to 632 nm of protein-bound astaxanthin. The calculations are consistent with a polarization mechanism that involves the protonation or another interaction with a positive ionic species of comparable magnitude with both ketofunctionalities of the astaxanthin-chromophore and support the changes observed in the resonance Raman and visible absorption spectra. The results are in good agreement with the conclusions that were drawn on the basis of a study of the charge densities in the chromophore in alpha-crustacyanin by solid-state NMR spectroscopy. From the results the dramatic bathochromic skiff can be explained not only from a change in the ground electronic state conformation but also from an interaction in the excited electronic state that significantly decreases the energy of the pi-antibonding C=O orbitals and the HOMO-LUMO gap. (C) 1999 John Wiley & Sons, Inc.
Weissburg, M. J. (1999). Tuning breadth and sex-specific sensitivity in chemosensory neurons of male and female Uca pugnax. Journal of Comparative Physiology a-Sensory Neural and Behavioral Physiology 185, 229-238.
Chemosensory neurons of female fiddler crabs (genus Uca) display greater sensitivity to mixtures of food-related stimuli than do neurons in males. This phenomenon represents an interesting contrast to other sex-specific systems, which tend to be in response to cues associated with mating and parental care. This study examined the responses of chemosensory neurons in males and females to ten individual stimuli to determine if sex-specific responses were restricted to a few key compounds, or if the heightened sensitivity of females was broadly distributed. Neurons in males and females responded well to all stimuli, and although fiddler crabs are primarily herbivorous, highly efficacious physiological stimulants included amino acids and amines as well as carbohydrates most closely associated with plant material. The chemosensory neurons are characterized by broad tuning and relatively high response thresholds, when compared to other crustaceans. Most importantly, the investigations revealed a robust pattern in which female neurons displayed elevated responses to all stimuli. Tuning breadth was not shown to be sex-specific, nor were there detectable differences in over-all response profiles. The most likely explanation for these patterns is that the broad sex-specificity in Uca is produced via fundamental alterations in cellular properties associated with chemosensory transduction.
West, J. M. (1997). Ultrastructural and contractile activation properties of crustacean muscle fibres over the moult cycle. Comparative Biochemistry and Physiology B-Biochemistry & Molecular Biology 117, 333-345.
Crustacean muscles are composed of muscle fibres with greatly different ultrastructure. At the time of ecdysis the large chelae muscle undergoes an atrophy triggered by the moult to aid in the withdrawal of the muscle mass. There appear to be distinct differences between the signs of atrophy observed in long- and shore sarcomere fibres during late premoult which are discussed in this review. Myofibrillar splitting is more evident in short sarcomere fibres while erosion within the myofibrillar bundles is more extensive in fibres with long sarcomeres. Immediately after ecdysis the carapace expands stretching the internal muscles. This review also describes the mechanisms that fibres with different ultrastructure use to elongate as the new exoskeleton expands. Fibres with short sarcomeres increase their length by inserting new sarcomeres along the length of the myofibril by transverse sarcomere splitting and Z line splitting. Long sarcomere fibres, however, may utilize mechanisms other than sarcomere insertion. Large electron dense structures located around the Z lines, in the A and I bands and between myofibrils are observed in long- sarcomere fibres thought to be undergoing lengthening. These structures may be involved in myofibrillar elongation. As elongation and atrophy involve changes to the myofibrillar lattice, the functional properties at certain stages of the moult cycle are discussed. Long-sarcomere fibres maintain their function over the moult cycle developing forces of similar magnitude in the intermoult, premoult and postmoult stages. The contractile properties of fibres with short sarcomeres were modified over the moult cycle as these fibres could not withstand maximal activation during the premoult stage suggesting that sarcomeric proteins have been disrupted. (C) 1997 Elsevier Science Inc.
Wheatly, M. G. (1999). Calcium homeostasis in crustacea: The evolving role of branchial, renal, digestive and hypodermal epithelia. Journal of Experimental Zoology 283, 620-640.
Crustaceans serve as an ideal model for the study of calcium homeostasis due to their natural molting cycle. Demineralization and remineralization of the calcified cuticle is accompanied by bidirectional Ca transfer across the primary Ca transporting epithelia: gills, antennal gland (kidney), digestive system, and cuticular hypodermis. The review will demonstrate how a continuum of crustaceans can be used as a paradigm for the evolution of Ca transport mechanisms. Generally speaking, aquatic crustaceans rely primarily on branchial Ca uptake and accordingly are affected by water Ca content; terrestrial crustaceans rely on intake of dietary Ca across the digestive epithelium. Synchrony of mineralization at the cuticle vs. storage sites will be presented. Physiological and behavioral adaptations have evolved to optimize Ca balance during the molting cycle in different Ca environments. Intracellular Ca regulation reveals common mechanisms of apical and basolateral membrane transport as well as intracellular sequestration. Regulation of cell Ca concentration will be discussed in intermolt and during periods of the molting cycle when transepithelial Ca flux is significantly elevated. Molecular characterization of the sarco-/endoplasmic reticular Ca pump in aquatic species reveals the presence of two isoforms that originate from a single gene. This gene is differentially expressed during the molting cycle. Gene expression may be regulated by a suite of hormones including ecdysone, calcitonin, and vitamin D. Perspectives for future research are presented. (C) 1999 Wiley-Liss, Inc.
Whiteley, N. M., and ElHaj, A. J. (1997). Regulation of muscle gene expression over the moult in crustacea. Comparative Biochemistry and Physiology B-Biochemistry & Molecular Biology 117, 323-331.
Muscle growth in crustacea occurs over the moult and involves a corresponding increase in fractional rates of sarcomeric protein synthesis. Heterologous and homologous cDNA probes for the myofibrillar protein, actin and myosin, have been used to investigate the factors responsible for controlling muscle growth in crustaceans at the molecular level. Factors such as passive stretch, caused by ecdysial expansion; moulting hormones such as ecdysteroids, which regulate the cycle of moult related events; and temperature, an environ mental factor known to influence the rates of many biochemical reactions, all play a role in modulating muscle growth in crustacea. In isopod crustaceans, the regulation of muscle growth produces new problems as these crustaceans are characterised by a biphasic moult cycle in which the posterior half of the old exoskeleton is shed hours to days before the anterior half. These animals therefore provide an ideal model for the study of differential muscle growth. In both decapod and isopod crustaceans, transcriptional regulation alone may not be sufficient to account far the the upregulation of sarcomeric protein synthesis during intermittent growth. Both passive stretch and elevated ecdysteroid titre increase protein synthesis rates for actin in lobster muscles, in vivo. These factors may be involved in the promotion of ribosomal activity and translational processing during ecdysial muscle growth. Temperature has a direct effect on protein synthesis rates and levels of actin mRNA expression and may be a principal factor in the control of seasonal moult cycles. (C) 1997 Elsevier Science Inc.
Wilkens, J. L., and McMahon, B. R. (1972). Aspects of branchial irrigation in the lobster Homarus americanus. I. Functional analysis of scaphognathite beat, water pressures and currents. J Exp Biol 56, 469-79.
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Wilkens, J. L., and Young, R. E. (1975). Patterns and bilateral coordination of scaphognathite rhythms in the lobster Homarus americanus. J Exp Biol 63, 219-35.
The bilateral patterns of forward and reversed scaphognathite (SG) pumping are described for the American lobster. During forward pumping the two SGs usually function synchronously, but may also function independently. The nine muscles of one SG are arranged into four functional groups which are sequentially active during forward pumping. During reversed beats, motor neurones to one group of muscles are inactive while bursts to another are either delayed or missing. Reversal beats do not appear to alter the phasing of the central oscillators that generate the basic SG rhythm. Phase analysis of bilateral SG beating demonstrates two types of relationship: phase coupling or phase drifting with a tendency to couple. An animal may remain in one state for long periods of time or may alternate between states. Coupling can occur at more than one phase indicating phase multistability. The coupled state may remain constant at markedly different frequencies of beating, indicating phase rather than latency coupling between SGs. During the drifting state each SG tends to assume its "intrinsic" rate of oscillation. The drift state reflects the inherent asymmetry of the two SG systems. The influence of several parameters of sensory stimulation on phase and frequency of SG beating are analyzed.
Wilkens, J. (1997). Possible mechanisms of control of vascular resistance in the lobster Homarus americanus. J Exp Biol 200, 487-93.
In Homarus americanus, the resistance to fluid flow through each of the arteries leaving the heart, including the complete hemocoelic return pathways, can be controlled. Each of the five arterial types (anterior median, paired anterior lateral, paired hepatic, sternal and dorsal abdominal) exhibits a unique spectrum of responses to a battery of neurotransmitters (acetylcholine, glutamic acid, -aminobutyric acid) and neurohormones (dopamine, octopamine, 5-hydroxytryptamine, crustacean cardioactive peptide, FLRFamide-related peptides F1 and F2, and proctolin). Acetylcholine causes increases in resistance in all arteries except the anterior median artery; in the dorsal abdominal artery, this increase is antagonized by -aminobutyric acid. All neurohormones that are effective in a particular artery cause increases in resistance to flow. The sites of action of these compounds in the dorsal abdominal artery are valves located at major branch points; the sites of control in the other arteries are not known. It is concluded that the control of arterial resistance is a mechanism which the animal can exploit to produce different flow patterns among the various arteries.
Wilkens, J., Davidson, G., and Cavey, M. (1997). Vascular peripheral resistance and compliance in the lobster Homarus americanus. J Exp Biol 200, 477-85.
The peripheral resistance to flow through each arterial bed (in actuality, the entire pathway from the heart back to the pericardial sinus) and the mechanical properties of the seven arteries leaving the lobster heart are measured and compared. Resistance is inversely proportional to artery radius and, for each pathway, the resistance falls non-linearly as flow rate increases. The resistance of the hepatic arterial system is lower than that predicted on the basis of its radius. Body-part posture and movement may affect the resistance to perfusion of that region. The total vascular resistance placed on the heart when each artery is perfused at a rate typical of in vivo flow rates is approximately 1.93 kPa s ml-1. All vessels exhibit adluminal layers of fibrils and are relatively compliant at pressures at or below heart systolic pressure. Arteries become stiffer at pressures greater than peak systolic pressure and at radii greater than twice the unpressurized radius. The dorsal abdominal artery possesses striated muscle in the lateral walls. This artery remains compliant over the entire range of hemolymph pressures expected in lobsters. These trends are illustrated when the incremental modulus of elasticity is compared among arteries. All arteries should function as Windkessels to damp the pulsatile pressures and flows generated by the heart. The dorsal abdominal artery may also actively regulate its flow.
Wilkens, J. L., and Kuramoto, T. (1998). Comparison of the roles of neurohormones in the regulation of blood distribution from the hearts of American and Japanese lobsters. Journal of Comparative Physiology B-Biochemical Systemic and Environmental Physiology 168, 483-490.
The decapod cardiovascular system consists of a single ventricle that pumps blood into seven arteries; previous work has shown that the outflow distribution patterns of intact animals are variable. In the present study, flow recordings were made from pairs of arteries in semi-isolated hearts whilst different cardioactive hormones were infused into the heart. Each hormone (5-hydroxytryptamine, octopamine, dopamine, proc tolin and Fl) changed the outflow pattern, heart rate and ventricular pressure in a unique way. The probable sites of hormone action are the cardioarterial valves located at the origin of each artery except one, the dorsal abdominal. Outflow from the dorsal abdominal is controlled downstream by valves located at the origin of the se,omental lateral arteries. The responses to a particular hormone were sometimes different between the hearts of American and Japanese lobsters.
Willis, J. H. (1999). Cuticular proteins in insects and crustaceans. American Zoologist 39, 600-609.
Comparisons between crustacean and insect cuticles are hampered by the paucity of cuticular protein sequences for the former. Sufficient complete sequences are available for insect cuticular proteins to allow recognition of conserved moths and relationships among proteins that reflect the type of cuticle from which they have been extracted. All five sequences from an arachnid and two of 14 from crustaceans have a moth found in the largest group of insect cuticular proteins. Numerous insights have been gained from studying insect cuticular proteins and their genes. These insights have been summarized in hopes of encouraging interest in building on the foundations laid by Dorothy Skinner with the exoskeleton of Gecarcinus.
Winlow, W., and Laverack, M. S. (1970). The occurrence of an anal proprioceptor in the decapod crustacea Homarus gammarus (L.) (syn. H. vulgaris M.Ed.) and Nephrops norvegicus (Leach). Life Sci 9, 93-7.
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Wojtowicz, M. B., and Brockerhoff, H. (1972). Isolation and some properties of the digestive amylase of the American lobster (Homarus americanus). Comp Biochem Physiol [B] 42, 295-302.
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Xu, F. Q., Hollins, B., Gress, A. M., Landers, T. M., and McClintock, T. S. (1997). Molecular cloning and characterization of a lobster G alpha(s) protein expressed in neurons of olfactory organ and brain. Journal of Neurochemistry 69, 1793-1800.
We have isolated from an American lobster (Homarus americanus) olfactory organ cDNA library a clone, lobG alpha(s), with >70% identity to mammalian and arthropod G alpha(s) sequences. In genomic Southern blots, a fragment of lobG alpha(s) detected only one band, suggesting the lobsters have a single G alpha(s) gene. In brain and olfactory organ, lobG alpha(s) mRNA was expressed predominantly in neurons, including many of the neuronal cell body clusters of the brain. G alpha(s) protein was also expressed broadly, appearing on western blots as a band of 51.8 kDa in brain, eyestalk, pereiopod, dactyl, tail muscle, olfactory organ, and aesthetasc hairs. These results suggest that lobG alpha(s) plays a role in a wide variety of signal transduction events. Its presence in the olfactory aesthetasc hairs, which are almost pure preparations of the outer dendrites of the olfactory receptor neurons, and the expression of lobG alpha(s) mRNA in the olfactory receptor neurons of the olfactory organ indicate that lobG alpha(s) may mediate olfactory transduction. That virtually all ORNs express lobG alpha(s) mRNA equally predicts that hyperpolarizing odor responses mediated by cyclic AMP are a property of all lobster olfactory receptor neurons.
Xu, F. Q., Hollins, B., Landers, T. M., and McClintock, T. S. (1998). Molecular cloning of a lobster G(beta) subunit and G(beta) expression in olfactory receptor neuron dendrites and brain neuropil. Journal of Neurobiology 36, 525-536.
We have isolated from the olfactory organ of the American lobster (Homarus americanus) two cDNA clones with homology to beta subunits of G proteins. LobG(beta 1) contained a complete open reading frame that predicted an amino acid sequence,vith >80% identity to G(beta) sequences from other species. LobG(beta 2) was a fragment of an open reading frame whose predicted amino acid sequence had 65-69% identity to other G(beta) sequences. LobG(beta 2) mRNA was not detectable in the brain, eye plus eyestalk, leg, dactyl, olfactory organ, or tail muscle. In contrast, lobG(beta 1) was expressed in all these tissues as a single mRNA species of 6.4 kb and a protein of 37 kD. In the brain and olfactory organ, G(beta) immunoreactivity was almost exclusively confined to neurites: the neuropil regions of the brain and the outer dendrites of the olfactory receptor neurons. Coimmunoprecipitation revealed that lobster G(beta) interacted with both G(alpha s) and G(alpha q). LabG(beta 1) is likely to be involved in a wide range of signaling events including olfactory transduction and synaptic transmission in the brain, (C) 1998 John Wiley & Sons, Inc.
Yang, W. J., Aida, K., and Nagasawa, H. (1997). Amino acid sequences and activities of multiple hyperglycemic hormones from the Kuruma prawn, Penaeus japonicus. Peptides 18, 479-485.
By means of a single-step reversed-phase HPLC, six CHH family peptides were isolated from sinus gland extracts of the kuruma prawn, Penaeus japonicus. Five of these peptides (Pej-SGP-I, - II, -III, -V, and -VI) expressed hyperglycemic activity and were considered to be the hyperglycemic hormones of this prawn. The amino acid sequences of the five peptides were determined (the amino acid sequence of Pej-SGP-III had been previously determined), revealing that all consisted of 72 amino acid residues with a free amino-terminus and an amidated carboxyl- terminus. They showed considerable sequence similarity to one another, but much less similarity to Pej-SGP-IV with molt- inhibiting activity, the sequence of which had also been determined previously. Examination of the dose-response relationship of these peptides showed that they were equally potent but had different efficacies, which were in the order of Pej-SGP-V, -VI > -III, -I > -II corresponding well with their sequence characteristics. (C) 1997 Elsevier Science Inc.
Yazawa, T., Wilkens, J. L., ter Keurs, H., and Cavey, M. J. (1999). Structure and contractile properties of the ostial muscle (musculus orbicularis ostii) in the heart of the American lobster. Journal of Comparative Physiology B-Biochemical Systemic and Environmental Physiology 169, 529-537.
"Venous" blood enters the crustacean heart through bivalved ostia. Each ostium is a discrete anatomical unit that remains functional even when isolated from the heart. Muscle fibers produce overshooting action potentials that have a plateau of variable duration in response to nervous drive from the cardiac ganglion or during trains of electrical stimuli. Contractions show summation and facilitation when stimulated by trains of stimuli delivered at rates greater than 0.5 s(-1) and 0.2 s(-1) respectively. Contraction amplitude increases with stimulating impulse frequency and train duration. Maximum force occurs at 1.2 times the slack length. The morphology of ostial fibers resembles that of myocardial fibers. Interconnected bundles of myofilaments occur in both the ostial fibers and the myocardial fibers. In ostial and myocardial fibers, the myofilament bundles are invested by perforated sheets of sarcoplasmic reticulum, and these sheets interface with a network of sarcolemmal tubules to form dyadic interior couplings at the level of the sarcomeric H-bands. The contractile apparatus originates and terminates at intermediate junctions on the transverse cellular boundaries, and the lateral surfaces of the muscle fibers are linked by a modest number of communicating (gap) junctions.
Yentsch, C. M., and Balch, W. (1975). Lack of secondary intoxification by red tide poison in the American lobster Homarus americanus. Environ Lett 9, 249-54.
Lobsters are able to feed on shellfish which are toxic with PSP (paralytic shellfish poisoning from Gonyaulax tamarensis) with no apparent harm to themselves, and no measurable assimilation of the poison into their tissues. Lobsters consumed food containing in excess of 1000 mug PSP. There was no impairment of respiration (oxygen consumption) measurable two to three hours after feeding, and no PSP measured in the meat of the claws and tail 48 to 120 hours after feeding. The only PSP was in the guts and contents which were measured 48 hours after feeding began.
Young, N. M., and Williams, R. E. (1983). The circular dichroism of ovoverdin and other carotenoproteins from the lobster Homarus americanus. Can J Biochem Cell Biol 61, 1018-24.
The circular dichroic (CD) spectra of the alpha-, beta'-, and gamma- crustacyanins, ovoverdin, and the yellow lobster-shell protein were measured in the region 200-750 nm, for comparison with the CD spectrum of the free carotenoid astaxanthin. The two carotenoid chromophores of ovoverdin gave a CD spectrum with a series of bands of alternating sign and ellipticities up to 1.9 X 10(5) degree X cm2 X dmol-1, comparable to the low temperature CD spectrum of astaxanthin in the UV region. The visible region of ovoverdin also contained strong CD bands where astaxanthin itself has very weak ones. The blue (640 nm) chromophore of ovoverdin gave a broad negative CD feature quite different from the blue chromophores of the three crustacyanins. The crustacyanins have a broad positive feature between 400 and 610 nm with ellipticities up to 2 X 10(5) degree X cm2 X dmol-1, followed at higher wavelengths by a negative band with an ellipticity up to 1 X 10(5) degree X cm2 X dmol- 1. Gaussian curve-fitting procedures showed the positive features to consist of a minimum of two or three CD bands. In addition to the exciton bands at the main visible absorption, the yellow lobster-shell protein had a pair of CD bands of equal but opposite ellipticity associated with an absorption band between 250 and 340 nm. The UV regions of the CD spectra of the five carotenoproteins have bands from both carotenoid and protein chromophores, and possible assignments of these bands to one or the other of the two types of chromophore are proposed.
Zeng, C. S., and Naylor, E. (1997). Rhythms of larval release in the shore crab Carcinus maenas (Decapoda: Brachyura). Journal of the Marine Biological Association of the United Kingdom 77, 451-461.
The process of larval release in field collected ovigerous Carcinus maenas was monitored in the laboratory using a time- lapse video recorder. Under constant light (L:L) and simulated natural light/dark cycles (L:D),larval release normally occurred in two or more main events at about daily and/or tidal intervals. Since larval release in the crab was expressed with circadian and circatidal periodicity in continuous light and in the absence of tidal cues, it suggests involvement of endogenous timing. Crabs showing daily larval release rhythms released larvae at various times of the day in L:L. In contrast, under simulated L:D cycles, 37 out of 38 crabs released larvae during the dark phase, suggesting nocturnal release of larvae in the crab under natural conditions. Larval release from freshly collected females which shed larvae within two days of collection occurred predominantly around the times of expected nocturnal high tide. When both local semidiurnal high tides occurred in daylight during long summer days, larval release appeared to start 2-3 h earlier than the expected morning high tide, before the onset of daylight. Larval release at the time around high tide, linked to a previously described larval tidal migration rhythm of ebb-phased upward swimming, is likely to have been selected for by enhancing the larval offshore dispersal process. Nocturnal larval release is probably adaptive in the avoidance of visual predators by ovigerous females as they release larvae.
Zhou, T., and Rebach, S. (1999). Chemosensory orientation of the rock crab Cancer irroratus. Journal of Chemical Ecology 25, 315-329.
The importance of chemical cues in the foraging behavior of the rock crab, Cancer irroratus, was investigated. Crabs were presented with mussel prey located upstream, downstream, or cross-stream. Trials were conducted under both light and dark conditions. With the prey upstream, the crabs exhibited the shortest search time and 100% searching success. There was a significant difference between how direction treatments, but there were no significant differences between light and dark treatments. When presented with mussel extract and a seawater control, crabs approached the source of the current. Analysis of search patterns revealed differences in search time, path length and straightness, and total number of turns. Chemoreception was the predominant mode of prey detection and was used in guiding crabs to their prey. Large variabilities in the search path and search path parameters were exhibited, and there was no fixed search pattern for orientation toward food while foraging. It is suggested that rock crabs employed both chemotaxis and rheotaxis for locating odor sources.
Zhuang, Z., Duerr, J., and Ahearn, G. (1995). Ca2+ and Zn2+ are transported by the electrogenic 2Na+/1H+ antiporter in echinoderm gastrointestinal epithelium. J Exp Biol 198, 1207-17.
45Ca2+ uptake by purified brush-border membrane vesicles of starfish (Pycnopodia helianthoides) pyloric ceca was stimulated by an outwardly directed H+ gradient and this stimulation was enhanced by the simultaneous presence of an induced membrane potential (inside negative; K+/valinomycin). External amiloride (competitive inhibitor; Ki=660 µmol l-1) and a monoclonal antibody raised against proteins associated with the lobster (Homarus americanus) electrogenic 2Na+/1H+ antiporter both inhibited approximately half of the proton- gradient-stimulated 45Ca2+ uptake. These results suggested that Ca2+ might be transported by the electrogenic antiporter and that the crustacean antibody was inhibitory to the exchange function in echinoderms, as was recently shown in crustacean epithelial brush- border membrane vesicles. Carrier-mediated 45Ca2+ influx by amiloride- sensitive and amiloride-insensitive systems displayed the following kinetic constants: (amiloride-sensitive) Kt=66±2 µmol l-1; Jmax=0.173±0.002 pmol µg-1 protein 8 s-1; (amiloride- insensitive) Kt=18±0.3 µmol l-1; Jmax=0.100±0.001 pmol µg-1 protein 8 s-1. Zn2+ was a mixed inhibitor of 45Ca2+ influx by carrier-mediated transport, displaying a Ki of 920 µmol l-1. Mn2+, Cu2+, Fe2+ and Mg2+ also inhibited 45Ca2+ uptake, but the mechanism(s) of inhibition by these other cations was not disclosed. An equilibrium shift experiment showed that both Na+ and Zn2+ were able to exchange with equilibrated 45Ca2+ in these vesicles, suggesting that both monovalent and divalent cations were able to enter pyloric cecal cells through a common carrier-mediated transport system. In addition, the echinoderm electrogenic system appeared to exhibit a molecular component recognized by the crustacean antibody that may imply a similar epitope in the two animals.
Zhuang, Z., and Ahearn, G. (1996). Ca2+ transport processes of lobster hepatopancreatic brush-border membrane vesicles. J Exp Biol 199, 1195-208.
45Ca2+ uptake by hepatopancreatic brush-border membrane vesicles of Atlantic lobster (Homarus americanus) occurred by a combination of three independent processes: (1) an amiloride-sensitive carrier- mediated transport system; (2) an amiloride-insensitive carrier- mediated transport system; and (3) a verapamil-inhibited channel process responsive to transmembrane potential. Both carrier-mediated processes were antiporters and capable of exchanging external Ca2+ with intravesicular Na+ or H+. The kinetic parameters of both carrier- mediated processes have been reported previously. External amiloride and Zn2+ were both competitive inhibitors of 45Ca2+ influx, reducing entry of the divalent cation at a single binding site with Ki values of 370 µmol l-1 for amiloride and 940 µmol l-1 for Zn2+. It is concluded that the mechanisms controlling Ca2+ entry into hepatopancreatic epithelial cells include a previously reported electrogenic 2Na+/1H+ antiporter, an electroneutral 2Na+/1Ca2+ antiporter and a verapamil-sensitive Ca2+ channel, which might also be used for the entry of Zn2+ and possibly other heavy metals. Evidence from an equilibrium-shift experiment, based on the thermodynamics of a coupled transport process, suggested that both monovalent (Na+) and divalent (Ca2+ and Zn2+) cations may enter hepatopancreatic epithelial cells through a common carrier-mediated transport protein. This suite of hepatopancreatic brush-border Ca2+ transport processes qualitatively resembles that previously reported for the luminal membrane of lobster antennal glands and suggests that crustacean epithelial cells from different organs may handle this divalent cation by similar means.
Zhuang, Z. P., and Ahearn, G. A. (1998). Energized Ca2+ transport by hepatopancreatic basolateral plasma membranes of Homarus americanus. Journal of Experimental Biology 201, 211-220.
Ca2+ transport by hepatopancreatic basolateral membrane vesicles of Atlantic lobster (Homarus americanus) occurred by at least two independent processes: (1) an ATP-dependent carrier transport system, and (2) a Na+-gradient-dependent carrier mechanism, The sensitivity of ATP-dependent Ca2+ transport to vanadate indicated that it was probably due to a P-type ATPase, This system exhibited an extremely high apparent affinity for Ca2+ (K-t=65.28+/-14.39 nmol l(-1); J(max)=1.07+/- 0.06 pmol mu g(-1) protein 8 s(-1)), The Na+-gradient-dependent carrier transport system exhibited the properties of a Ca2+/Na+ antiporter capable of exchanging external Ca2+ with intravesicular Na+ or Li+, Kinetic analysis of the Na+- dependence of the antiport indicated that at least three Na+ were exchanged with each Ca2+ (n=2.91+/-0.22), When Li+ replaced Na+ in exchange for Ca-45(2+), the apparent affinity for Ca2+ influx was not significantly affected (with Naf, K- t=14.57+/-5.02 mu mol l(-1); with Li+, K-t=20.17+/-6.99 mu mol l(-1)), but the maximal Ca2+ transport velocity was reduced by a factor of three (with Na+, J(max)=2.72+/-0.23 pmol mu g(-1) protein 8 s(-1); with Li+, J(max)=1.03+/-0.10 pmol mu g(-1) protein 8 s(-1)), It is concluded that Ca2+ leaves hepatopancreatic epithelial cells across the basolateral membrane by way of a high-affinity, vanadate-sensitive Ca2+- ATPase and by way of a low-affinity Ca2+/Na+ antiporter with an apparent 3:1 exchange stoichiometry. The roles of these transporters in Ca2+ balance during the molt cycle are discussed.
Zlateva, T., Di Muro, P., Salvato, B., and Beltramini, M. (1996). The o-diphenol oxidase activity of arthropod hemocyanin. FEBS Lett 384, 251-4.
Arthropod hemocyanin (isolated from the crab Carcinus maenas and the lobster Homarus americanus) is usually referred to as an oxygen transport-storage protein. The protein, however, also catalyses with low efficiency the oxidation of o-diphenol to quinone, similarly to tyrosinase (monophenol, o-diphenol:oxygen oxidoreductase). The enzymatic parameters of hemocyanin are affected by the aggregation state of the protein; namely V(max) exhibited by a dissociated subunit is one order of magnitude greater than that of aggregated species. The reaction velocity is increased by the presence of perchlorate, an anion of the Hofmeister series. The results are also discussed on the basis of active site accessibility in comparison with tyrosinase.
Zollman, J. R., and Gainer, H. (1971). Electrophysiological properties of nerve cell bodies in the sixth abdominal ganglion of the Maine lobster, Homarus americanus. Comp Biochem Physiol A 38, 407-33.
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