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 strong