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feedback from peripheral musculature to central pattern generator in the neurogenic heart of the crab callinectes sapidus: role of mechanosensitive dendrites.the neurogenic heart of decapod crustaceans is a very simple, self-contained, model central pattern generator (cpg)-effector system. the cpg, the nine-neuron cardiac ganglion (cg), is embedded in the myocardium itself; it generates bursts of spikes that are transmitted by the cg's five motor neurons to the periphery of the system, the myocardium, to produce its contractions. considerable evidence suggests that a cpg-peripheral loop is completed by a return feedback pathway through which the cont ...201019828726
bioaccumulation and depuration of metals in blue crabs (callinectes sapidus rathbun) from a contaminated and clean estuary.blue crabs from a contaminated estuary (hackensack meadowlands-hm) and a cleaner reference site (tuckerton-tk) were analyzed for cr, cu, hg, pb, and zn in muscle and hepatopancreas. crabs from each site were taken into the laboratory and fed food from the other site, or in another experiment, transplanted to the other site for eight weeks. all crabs were analyzed for metals. overall, tissue concentrations reflected environmental conditions. tissue differences were found for cu, pb and zn (all hi ...201019783083
decoding modulation of the neuromuscular transform.when modulators of neuromuscular function alter the motor neuron spike patterns that elicit muscle contractions, it is predicted that they will also retune correspondingly the connecting processes of the neuromuscular transform. here we confirm this prediction by analyzing data from the cardiac neuromuscular system of the blue crab. we apply a method that decodes the contraction response to the spike pattern in terms of three elementary building-block functions that completely characterize the n ...200719763188
transmission of the parasitic dinoflagellate hematodinium sp. infection in blue crabs callinectes sapidus by cannibalism.infection with the parasitic dinoflagellate hematodinium sp. can be devastating to blue crab callinectes sapidus populations. morbidity and mortality appear to depend on the burden of parasitic organisms. heavily infected crabs become lethargic and, if not preyed upon, succumb to overwhelming infection. we report on the transmission of hematodinium sp. into blue crabs that were fed pieces of infected tissues and examined for evidence of infection at time periods from 1 to 48 h and for the genera ...200919750807
anatomy of virgin and mature externae of loxothylacus texanus, parasitic on the dark blue crab callinectes rathbunae (crustacea: cirripedia: rhizocephala: sacculinidae).rhizocephalan parasites are dioecious organisms, in that one or several dwarf males are implanted into the external part of the female parasite soon after it emerges from the interior of the host animal. the structure of the female externa and its resident males is crucial for understanding both the reproductive biology and the taxonomy of these specialized parasites. we use scanning electron microscopy and histological methods to study the anatomy of juvenile and the mature externae of the rhiz ...201019714752
complete mitochondrial genome of the asian paddle crab charybdis japonica (crustacea: decapoda: portunidae): gene rearrangement of the marine brachyurans and phylogenetic considerations of the decapods.given the commercial and ecological importance of the asian paddle crab, charybdis japonica, there is a clearly need for genetic and molecular research on this species. here, we present the complete mitochondrial genome sequence of c. japonica, determined by the long-polymerase chain reaction and primer walking sequencing method. the entire genome is 15,738 bp in length, encoding a standard set of 13 protein-coding genes, two ribosomal rna genes, and 22 transfer rna genes, plus the putative cont ...201019714481
respiratory and digestive responses of postprandial dungeness crabs, cancer magister, and blue crabs, callinectes sapidus, during hyposaline exposure.respiratory responses and gastric processing were examined during hyposaline exposure in two crab species of differing osmoregulatory ability. the efficient osmoregulator, callinectes sapidus, displayed an immediate increase in oxygen uptake when exposed to low salinity in isolation. in contrast, the weak osmoregulator, cancer magister, showed no change in oxygen uptake upon acute exposure (<6 h), but slight increases in oxygen uptake tended to occur over longer time scales (12-24 h). these chan ...201019714337
molt-inhibiting hormone stimulates vitellogenesis at advanced ovarian developmental stages in the female blue crab, callinectes sapidus 1: an ovarian stage dependent involvement.to understand the hormonal coordination of the antagonism between molting and reproduction in crustaceans, the terminally anecdysial mature female callinectes sapidus was used as a model. the regulatory roles of crustacean hyperglycemic hormone (chh) and molt-inhibiting hormone (mih) in vitellogenesis were examined. a competitive specific ria was used to measure the levels of mih and chh in the hemolymphs of mature females at pre- and mid- vitellogenic stages, and their effects on vitellogenesis ...200919583852
molt-inhibiting hormone stimulates vitellogenesis at advanced ovarian developmental stages in the female blue crab, callinectes sapidus 2: novel specific binding sites in hepatopancreas and camp as a second messenger.the finding that molt-inhibiting hormone (mih) regulates vitellogenesis in the hepatopancreas of mature callinectes sapidus females, raised the need for the characterization of its mode of action. using classical radioligand binding assays, we located specific, saturable, and non-cooperative binding sites for mih in the y-organs of juveniles (j-yo) and in the hepatopancreas of vitellogenic adult females. mih binding to the hepatopancreas membranes had an affinity 77 times lower than that of juve ...200919583849
hemolymph ecdysteroids during the last three molt cycles of the blue crab, callinectes sapidus: quantitative and qualitative analyses and regulation.the profiles of circulating ecdysteroids during the three molt cycles prior to adulthood were monitored from the juvenile blue crab, callinectes sapidus. ecdysteroid patterns are remarkably similar in terms of peak concentrations ranging between 210-330 ng/ml hemolymph. analysis of hemolymph at late premolt stage revealed six different types of ecdysteroids with ponasterone a (poa) and 20-oh ecdysone (20-oh e) as the major forms. this ecdysteroid profile was consistent in all three molt cycles. ...201019557853
na+, k+-atpase activity in gill microsomes from the blue crab, callinectes danae, acclimated to low salinity: novel perspectives on ammonia excretion.this investigation provides an extensive characterization of the modulation by atp, mg(2+), na(+), k(+) and nh(4)(+) of a gill microsomal (na(+),k(+))-atpase from callinectes danae acclimated to 15 per thousand salinity. novel findings are the lack of high-affinity atp-binding sites and a 10-fold increase in enzyme affinity for k(+) modulated by nh(4)(+), discussed regarding nh(4)(+) excretion in benthic marine crabs. the (na(+),k(+))-atpase hydrolyzed atp at a maximum rate of 298.7+/-16.7 nmol ...200919535031
real-time pcr-based assay for quantitative detection of hematodinium sp. in the blue crab callinectes sapidus.hematodinium sp. is a parasitic dinoflagellate infecting the blue crab callinectes sapidus and other crustaceans. pcr-based assays are currently being used to identify infections in crabs that would have been undetectable by traditional microscopic examination. we therefore sought to define the limits of quantitative pcr (qpcr) detection within the context of field collection protocols. we present a qpcr assay based on the hematodinium sp. 18s rrna gene that can detect 10 copies of the gene per ...200919419009
daggerblade grass shrimp (palaemonetes pugio): a reservoir host for yellow-head virus (yhv).yellow-head virus (yhv) is a major pathogen in penaeid shrimps. we surveyed 13 crustacean species in eight families from two orders that are commonly found in the mississippi coastal area and freshwater environments as potential reservoir or carrier hosts of yhv. using semi-nested polymerase chain reaction (pcr) on relatively small sample sizes, we did not detect any natural infection. however, when the daggerblade grass shrimp, palaemonetes pugio, and the blue crab, callinectes sapidus, were ex ...200919409902
comparison of fatty acid and proximate compositions of the body and claw of male and female blue crabs (callinectes sapidus) from different regions of the mediterranean coast.fatty acid and proximate compositions of the body and claw of male and female blue crabs from akyatan lagoon and hurma strait were investigated. male blue crab meat had a higher protein and fat content, and lower moisture and ash content, than that of the female from akyatan lagoon. moreover, there were variations of protein and fat amounts in both female crab meats between akyatan lagoon and hurma strait. the dominant saturated fatty acids were palmitic acid (16:0; range from approximately 12% ...200819382333
spontaneous alternation in marine crabs: invasive versus native species.organisms ranging from paramecia to humans tend to explore places that have been least recently explored, which is referred to as spontaneous alternation. although organisms rely on different sources of information in alternating between places, the emergent behavioral pattern is likely advantageous during exploration and foraging. under this rationale, continuous spontaneous alternation performance of the invasive green crab, carcinus maenas was assessed and compared with the native blue crab, ...200919379799
molecular cloning of the crustacean hyperglycemic hormone (chh) precursor from the x-organ and the identification of the neuropeptide from sinus gland of the alaskan tanner crab, chionoecetes bairdi.crustacean hyperglycemic hormone (chh) secreted from sinus glands primarily elicits hyperglycaemia in crustaceans. chh is particularly important for energy metabolism during environmental and physiological stress as animals switch to anaerobiosis. chh has been purified from multiple brachyuran crab species to date, but not from the cold water tanner crab, chionoecetes bairdi, a species found in alaskan coastal waters. the purpose of molecular cloning the c. bairdi chh precursor and identificatio ...200919332072
a skeletal muscle model of extreme hypertrophic growth reveals the influence of diffusion on cellular design.muscle fibers that power swimming in the blue crab callinectes sapidus are <80 microm in diameter in juveniles but grow hypertrophically, exceeding 600 microm in adults. therefore, intracellular diffusion distances become progressively greater as the animals grow and, in adults, vastly exceed those in most cells. this developmental trajectory makes c. sapidus an excellent model for characterization of the influence of diffusion on fiber structure. the anaerobic light fibers, which power burst sw ...200919321701
the specific binding sites of eyestalk- and pericardial organ-crustacean hyperglycaemic hormones (chhs) in multiple tissues of the blue crab, callinectes sapidus.crustacean hyperglycaemic hormone from the pericardial organ (po-chh) is a chh-related neuropeptide but its function and target tissues are not known in crustaceans. to investigate this issue, we employed radiolabelled ligand binding and cgmp assays, using eyestalk-chh (es-chh) as a reference neuropeptide. the membranes were prepared from various tissues of callinectes sapidus: hepatopancreas, hindgut, midgut, gills, heart, abdominal muscles and scaphognathites. like es-chh, recombinant po-chh ( ...200919181902
perfluoroalkyl acids in marine organisms from lake shihwa, korea.to our knowledge, this is the first report of concentrations of perfluorooctanesulfonate (pfos) and other perfluoroalkyl acids (pfas) in marine organisms from the industrialized region of korea. concentrations of eight pfas were determined in three species of fish (mullet, shad, and rockfish) and three species of marine invertebrates (blue crab, oyster, and mussel) from lake shihwa, korea. this is an area in which relatively great concentrations of pfas in water and in adjacent industrial efflue ...200919152061
copper accumulation and toxicity in isolated cells from gills and hepatopancreas of the blue crab (callinectes sapidus).in the present study, we used fresh preparations of mixed-cell populations to evaluate accumulation and toxicity of dissolved copper (1-100 microm) in isolated cells from posterior gills and hepatopancreas of the blue crab (callinectes sapidus). for both gill and hepatopancreatic cells, significant increases in copper accumulation were observed after exposure to 50 or 100 microm copper. in gill cells, a linear increase in copper accumulation was observed over time. in hepatopancreatic cells, a m ...200919143457
habitat complexity influences cascading effects of multiple predators.although multiple predator effects and trophic cascades have both been demonstrated in a wide variety of ecosystems, ecologists have yet to incorporate these studies into an experimental framework that also manipulates a common and likely important factor, spatial heterogeneity. we manipulated habitat complexity, the presence of two top predators (toadfish and blue crabs), and one intermediate predator (mud crabs) to determine whether habitat complexity influences the strength of multiple predat ...200819137947
a trehalose 6-phosphate synthase gene of the hemocytes of the blue crab, callinectes sapidus: cloning, the expression, its enzyme activity and relationship to hemolymph trehalose levels.trehalose in ectoderms functions in energy metabolism and protection in extreme environmental conditions. we structurally characterized trehalose 6-phosphate synthase (tps) from hemocytes of the blue crab, callinectes sapidus. c. sapidus hemo tps (cashemotps), like insect tps, encodes both tps and trehalose phosphate phosphatase domains. trehalose seems to be a major sugar, as it shows higher levels than does glucose in hemocytes and hemolymph. increases in hemotps expression, tps enzyme activit ...200819077285
metallothionein-like proteins in the blue crab callinectes sapidus: effect of water salinity and ions.the effect of water salinity and ions on metallothionein-like proteins (mtlp) concentration was evaluated in the blue crab callinectes sapidus. mtlp concentration was measured in tissues (hepatopancreas and gills) of crabs acclimated to salinity 30 ppt and abruptly subjected to a hypo-osmotic shock (salinity 2 ppt). it was also measured in isolated gills (anterior and posterior) of crabs acclimated to salinity 30 ppt. gills were perfused with and incubated in an isosmotic saline solution (iss) o ...200919049896
crustacean molt-inhibiting hormone: structure, function, and cellular mode of action.in crustacea, secretion of ecdysteroid molting hormones by y-organs is regulated, at least in part, by molt-inhibiting hormone (mih), a polypeptide neurohormone produced by neurosecretory cells of the eyestalks. this article reviews current knowledge of mih, with particular emphasis on recent findings regarding the (a) structure of the mih peptide and gene, (b) levels of mih in eyestalks and hemolymph, (c) cellular mechanism of action of mih, and (d) responsiveness of y-organs to mih. at least 2 ...200919000932
clearance of vibrio campbellii injected into the hemolymph of callinectes sapidus, the atlantic blue crab: the effects of prior exposure to bacteria and environmental hypoxia.the atlantic blue crab, callinectes sapidus (rathbun), lives in a bacteria-rich environment that experiences daily fluctuations in water quality. in the present study, we tested the hypothesis that crustaceans with prior or ongoing exposure to bacteria in their hemolymph have an increased susceptibility to subsequent infections, and that acute exposure to low dissolved oxygen (hypoxia) and elevated carbon dioxide levels (hypercapnia) may further confound the ability of blue crabs to counter a su ...200818964085
the fungus lagenidium callinectes couch (1942) on eggs of the blue crab in chesapeake bay. 194818887846
hepatopancreas alteration of the blue crab callinectes sapidus by the rhizocephalan barnacle loxothylacus texanus.a histological study of the hepatopancreas of the blue crab callinectes sapidus parasitized by the rhizocephalan barnacle loxothylacus texanus was conducted to explore if the degree of development of the parasite's rootlet system was correlated to its maturation process as seen by external characters of its reproductive body or externa. four types of crabs were examined: control, with virgin and mature externa, and scarred. a clear progression with an increase in number and size of the parasite' ...200818805422
the crustacean gill (na+,k+)-atpase: allosteric modulation of high- and low-affinity atp-binding sites by sodium and potassium.the blue crab, callinectes danae, tolerates exposure to a wide salinity range employing mechanisms of compensatory ion uptake when in dilute media. although the gill (na+,k+)-atpase is vital to hyperosmoregulatory ability, the interactions occurring at the sites of atp binding on the molecule itself are unknown. here, we investigate the modulation by na+ and k+ of homotropic interactions between the atp-binding sites, and of phosphoenzyme formation of the (na+,k+)-atpase from the posterior gills ...200818796291
spiny lobsters detect conspecific blood-borne alarm cues exclusively through olfactory sensilla.when attacked by predators, diverse animals actively or passively release molecules that evoke alarm and related anti-predatory behavior by nearby conspecifics. the actively released molecules are alarm pheromones, whereas the passively released molecules are alarm cues. for example, many insects have alarm-signaling systems that involve active release of alarm pheromones from specialized glands and detection of these signals using specific sensors. many crustaceans passively release alarm cues, ...200818689413
myzobdella platensis (hirundinida: piscicolidae) is true parasite of blue crabs (crustacea: portunidae).leeches exhibit a marked scope of diversity, including different kinds of symbiosis. the aim of the present study was to demonstrate through biochemical and histological analysis that a species of piscicolid leech, myzobdella platensis, is a true parasite of blue crabs, feeding on their hemolymph and using them as a site for cocoon deposition. in a total of 48 blue crabs collected on october 2007 at 3 sites of the são vicente estuary, 12 specimens were infested with leeches. callinectes bocourti ...200918601577
development of a denaturing high-performance liquid chromatography method for detection of protist parasites of metazoans.increasingly, diseases of marine organisms are recognized as significant biotic factors affecting ecosystem health. however, the responsible disease agents are often unknown and the discovery and description of novel parasites most often rely on morphological descriptions made by highly trained specialists. here, we describe a new approach for parasite discovery, utilizing denaturing high-performance liquid chromatography (dhplc) reverse-phase ion-pairing technology. systematic investigations of ...200818502933
detection and discovery of crustacean parasites in blue crabs (callinectes sapidus) by using 18s rrna gene-targeted denaturing high-performance liquid chromatography.recently, we described a novel denaturing high-performance liquid chromatography (dhplc) approach useful for initial detection and identification of crustacean parasites. because this approach utilizes general primers targeted to conserved regions of the 18s rrna gene, a priori genetic sequence information on eukaryotic parasites is not required. this distinction provides a significant advantage over specifically targeted pcr assays that do not allow for the detection of unknown or unsuspected p ...200818502913
[temporal and spatial distribution of the crab callinectes sapidus (decapoda: portunidae) in chetumal bay, quintana roo, mexico].in order to determine temporal and spatial distribution patterns of callinectes sapidus, samplings were carried out during the cold-front (january-february), dry (may-june) and rainy (august-september, 2002) climatic seasons, in 30 sampling stations of chetumal bay, grouped in sectors a (14 stations), b (eight stations) and c (eight stations). in each sampling station crabs were collected from two transects parallel to the coast, each with three traps, separated by 30 m. sediments were calcareou ...200718457132
simulated predator extinctions: predator identity affects survival and recruitment of oysters.the rate of species loss is increasing at a global scale, and human-induced extinctions are biased toward predator species. we examined the effects of predator extinctions on a foundation species, the eastern oyster (crassostrea virginica). we performed a factorial experiment manipulating the presence and abundance of three of the most common predatory crabs, the blue crab (callinectes sapidus), stone crab (menippe mercenaria), and mud crab (panopeus herbstii) in estuaries in the eastern united ...200818409432
to paddle or not: context dependent courtship display by male blue crabs, callinectes sapidus.the nature of the courtship signalling used by a species is shaped by many factors, one of which is its habitat. male blue crabs, callinectes sapidus, have a courtship display in which they elevate their body by standing high on their legs, open their chelae and paddle their swimming legs. this courtship display is not reported in other swimming (portunid) crabs and is rarely expressed in laboratory experiments on male blue crabs. in this study, we characterised this display, which we call ;cour ...200818375848
functional studies of crustacean hyperglycemic hormones (chhs) of the blue crab, callinectes sapidus - the expression and release of chh in eyestalk and pericardial organ in response to environmental stress.the rapid increase in the number of putative cdna sequences encoding crustacean hyperglycemic hormone (chh) family in various tissues [either from the eyestalk (es) or elsewhere] underscores a need to identify the corresponding neuropeptides in relevant tissues. moreover, the presence of provided structural chh implies the level of the complexity of physiological regulation in crustaceans. much less is known of the functions of non-es chh than of those of its counterpart present in ess. in the b ...200818190527
human and crab exposure to mercury in the caribbean coastal shoreline of colombia: impact from an abandoned chlor-alkali plant.human hair samples from male and female people aged 6-85 years, as well as muscle of crabs (callinectes sapidus and callinectes bocourti) were collected from different fishing places along the caribbean coastal shoreline of colombia and analyzed for total mercury (t-hg) in order to establish the impact of mercury-polluted sediments in cartagena bay on the ecosystem. hair t-hg in inhabitants varied between 0.1 and 21.8 microg/g, with average and median of 1.52 microg/g and 1.1 microg/g, respectiv ...200818155151
a study of the form and growth of the blue crab callinectes sapidus rathbun. 194918153117
differential growth and moulting characteristics of the blue crab, callinectes sapidus rathbun. 194918113443
studies of a receptor guanylyl cyclase cloned from y-organs of the blue crab (callinectes sapidus), and its possible functional link to ecdysteroidogenesis.crustacean y-organs synthesize ecdysteroid molting hormones. synthesis of ecdysteroids by y-organs is negatively regulated by a polypeptide neurohormone, molt-inhibiting hormone (mih). our laboratory has recently cloned from y-organs of the blue crab (callinectes sapidus) a cdna (csgc-yo1) encoding a putative receptor guanylyl cyclase (csgc-yo1). we hypothesize that csgc-yo1 is an mih receptor. in studies reported here, antipeptide antibodies (anti-csgc-yo1) were raised against a fragment of the ...200818093588
molt-inhibiting hormone immunoreactive neurons in the eyestalk neuroendocrine system of the blue crab, callinectes sapidus.the production of ecdysteroid molting hormones by crustacean y-organs is negatively regulated by a neuropeptide, molt-inhibiting hormone. it is generally agreed that molt-inhibiting hormone is produced and released by the eyestalk neuroendocrine system. in the present study, immunocytochemical methods were used to detect molt-inhibiting hormone immunoreactive neurons in eyestalk ganglia of the blue crab, callinectes sapidus. the primary antiserum used was generated against molt-inhibiting hormon ...200118088946
mechanical properties of the rigid and hydrostatic skeletons of molting blue crabs, callinectes sapidus rathbun.molting in crustaceans involves significant changes in the structure and function of the exoskeleton as the old cuticle is shed and a new one is secreted. the flimsy new cuticle takes several days to harden and during this time crabs rely on a hydrostatic skeletal support system for support and movement. this change from a rigid to a hydrostatic skeletal support mechanism implies correlated changes in the function, and thus mechanical properties, of the cuticle. in particular, it must change fro ...200718055616
identification of the extracellular copper-zinc superoxide dismutase (eccuznsod) gene of the mud crab scylla serrata and its expression following beta-glucan and peptidoglycan injections.an extracellular copper-zinc superoxide dismutase (eccuznsod, or ec-sod) gene was cloned from haemocytes of mud crab scylla serrata. the eccuznsod cdna consists of 939 bp with an open reading frame (orf) of 585 bp that encodes 195 amino acids (aa) with 31 residues of a signal peptide sequence. the predicted molecular mass of the mature protein (164aa) is 17.1 kda with an estimated pi of 6.89. amino acids responsible for binding cu (his84, 86, 101, and 163) and zn (his101, 109, and 121, and asp 1 ...200817949815
clostridium botulinum type f: isolation from crabs.two proteolytic strains of clostridium botulinum type f have been isolated from crabs (callinectes sapidus) from the york river in virginia. this is the first time proteolytic strains of this type have been isolated in the united states and the first demonstration of the presence of type f on the eastern coast of the united states.196817836660
the common blue crab in fresh waters. 193817832161
fungus infection of eggs of the blue crab callinectes sapidus rathbun. 194417814291
regulation of the crab heartbeat by fmrfamide-like peptides: multiple interacting effects on center and periphery.we are studying the functional "logic" of neuromodulatory actions in a simple central pattern generator (cpg)-effector system, the heart of the blue crab callinectes sapidus. the rhythmic contractions of this heart are neurogenic, driven by rhythmic motor patterns generated by the cardiac ganglion (cg). here we used anatomical and physiological methods to examine the sources and actions on the system of the fmrfamide-like peptides (flps) tnrnflrfamide (f(1)), sdrnflrfamide (f(2)), and gynrsflrfa ...200717804580
note on the absorption of calcium during the molting of the blue crab, callinectes sapidus. 191417787849
hatching of the blue crab, callinectes sapidus rathbun. 194217758353
a sex-specific metabolite identified in a marine invertebrate utilizing phosphorus-31 nuclear magnetic resonance.hormone level differences are generally accepted as the primary cause for sexual dimorphism in animal and human development. levels of low molecular weight metabolites also differ between men and women in circulating amino acids, lipids and carbohydrates and within brain tissue. while investigating the metabolism of blue crab tissues using phosphorus-31 nuclear magnetic resonance, we discovered that only the male blue crab (callinectes sapidus) contained a phosphorus compound with a chemical shi ...200717712428
biological studies on the blue crab portunus pelagicus and its parasitic infection in kuwaiti waters.the study investigated the parasites of symbiotic fauna of the blue crab, portunus pelagicus and the environmental factors, which was lacking in kuwait. p. pelagicus feeding habits was studied by examination of the digestive tract. the foregut (stomach) contents of 250 crabs (110 male & 140 female) collected from fish-market, souq-sharq, edelyia capital governorate were investigated. a barnacle, balanus sp. and staked barnacle octolasmis sp. (crustacea: cirripedia) were found strongly firmly to ...200717580579
salinity-stimulated changes in expression and activity of two carbonic anhydrase isoforms in the blue crab callinectes sapidus.two isoforms of the enzyme carbonic anhydrase (ca) in the blue crab gill, cascag and cascac, were identified, sequenced, and found to match the membrane-associated and cytoplasmic isoforms, respectively. the membrane-associated isoform is present in much higher levels of mrna expression in both anterior and posterior gills in crabs acclimated to high salinity (35 p.p.t.), but expression of the cytoplasmic isoform in the posterior gill undergoes a significantly greater degree of up-regulation aft ...200717575037
ultrastructure, histochemistry, and mineralization patterns in the ecdysial suture of the blue crab, callinectes sapidus.the ecdysial suture is the region of the arthropod exoskeleton that splits to allow the animal to emerge during ecdysis. we examined the morphology and composition of the intermolt and premolt suture of the blue crab using light microscopy and scanning electron microscopy. the suture could not be identified by routine histological techniques; however 3 of 22 fluorescein isothiocyanate-labeled lectins tested (lens culinaris agglutinin, vicia faba agglutinin, and pisum sativum agglutinin) differen ...200517481327
characterization of a shrimp serine protease homolog, a binding protein of yellow head virus.a serine protease homolog (sph) cdna namely sph516 was identified via a yeast two-hybrid screen between yellow head virus (yhv) proteins and hemocyte proteins of the black tiger shrimp penaeus monodon. initially, the c-terminal region of sph516 (sph516-c) was found to interact with a putative metal ion-binding domain (mib) encoded by open-reading of frame orf1b of the yhv genome. subsequently, the full-length of sph516 cdna was obtained using 5' rapid amplification of cdna ends (5' race) and it ...200717451807
risk of handling as a route of exposure to infectious waterborne cryptosporidium parvum oocysts via atlantic blue crabs (callinectes sapidus).commercial atlantic blue crabs (callinectes sapidus) were exposed to 2.0x10(4) infectious waterborne oocysts of cryptosporidium parvum. the study demonstrated that blue crabs can transfer c. parvum oocysts to persons involved in handling or preparing crabs and that they may contaminate other surfaces or products during storage.200717449680
vitellogenin and its messenger rna during ovarian development in the female blue crab, callinectes sapidus: gene expression, synthesis, transport, and cleavage.blue crab vitellogenin (vtg) cdna encodes a precursor that, together with two other brachyuran vtgs, forms a distinctive cluster within a phylogenetic tree of crustacean vtgs. using quantitative rt-pcr, we found that vtg was primarily expressed in the hepatopancreas of a vitellogenic female, with minor expression in the ovary. vtg expression in the hepatopancreas correlated with ovarian growth, with a remarkable 8000-fold increase in expression from stage 3 to 4 of ovarian development. in contra ...200717409377
antilipopolysaccharide factor (alf) of mud crab scylla paramamosain: molecular cloning, genomic organization and the antimicrobial activity of its synthetic lps binding domain.antilipopolysaccharide factors (alfs) are small basic proteins that can bind and neutralize lipopolysaccharide (lps) and have broad spectrum antimicrobial activities. in this study, we describe the isolation of the full-length cdna encoding for alf peptide (alfsp) of mud crab, scylla paramamosain by sequencing a hemocyte cdna library and using the rapid amplification cdna end (race) method. a full-length alfsp cdna of 614 bp contains an open reading frame (orf) of 372 bp, encoding 123 amino acid ...200717368541
regulation of the crab heartbeat by crustacean cardioactive peptide (ccap): central and peripheral actions.in regulating neurophysiological systems, neuromodulators exert multiple actions at multiple sites in such a way as to control the activity in an integrated manner. we are studying how this happens in a simple central pattern generator (cpg)-effector system, the heart of the blue crab callinectes sapidus. the rhythmic contractions of this heart are neurogenic, driven by rhythmic motor patterns generated by the cardiac ganglion (cg). in this study, we used anatomical and physiological methods to ...200717303813
k+ and nh4(+) modulate gill (na+, k+)-atpase activity in the blue crab, callinectes ornatus: fine tuning of ammonia excretion.to better comprehend the mechanisms of ionic regulation, we investigate the modulation by na+, k+, nh4(+) and atp of the (na+, k+)-atpase in a microsomal fraction from callinectes ornatus gills. atp hydrolysis obeyed michaelis-menten kinetics with km=0.61+/-0.03 mmol l(-1) and maximal rate of v=116.3+/-5.4 u mg(-1). stimulation by na+ (v=110.6+/-6.1 u mg(-1); k0.5=6.3+/-0.2 mmol l(-1)), mg2+ (v=111.0+/-4.7 u mg(-1); k0.5=0.53+/-0.03 mmol l(-1)), nh4(+) (v=173.3+/-6.9 u mg(-1); k0.5=5.4+/-0.2 mmo ...200717276114
superfund dredging restoration results in widespread regional reduction in cadmium in blue crabs.a nickel-cadmium battery factory released about 53 tons of mostly cadmium and nickel hydroxide suspended solid waste between 1953 and 1979 into foundry cove, which is tidally connected to the hudson river estuary. a major superfund dredging cleanup in 1994-1995 removed most of the cadmium from the sediment from within foundry cove. here, we demonstrate that the cleanup reduced cadmium tissue concentrations (hepatopancreas and leg muscle) in an important fishery species, the blue crab callinectes ...200617256500
differential expression of eight transcripts and their roles in the cuticle of the blue crab, callinectes sapidus.eight cuticle protein transcripts from callinectes sapidus were sequenced and their expression determined across the molt cycle in both calcifying and arthrodial cuticle hypodermis using quantitative pcr, northern blots, and in situ hybridization. four transcripts, designated csamp, are found only in non-calcifying arthrodial membrane hypodermis. they all code for a rebers-riddiford-1 motif, known to bind chitin. csamp9.3 is most likely an exocuticle constituent since it is expressed only during ...200717188921
molecular cloning, characterization and expression of a masquerade-like serine proteinase homologue from black tiger shrimp penaeus monodon.a full-length cdna of a masquerade-like serine proteinase homologue (pmmassph) of penaeus monodon was cloned and characterized by rapid amplification cdna end (race) method. the complete cdna sequence of 1958bp contains an open reading frame (orf) of 1572bp, encoding a 523 amino acid protein including a 19 amino acid signal peptide. the calculated molecular mass of the mature protein (504 amino acids) is 51.58kda with an estimated pi of 4.86. pmmassph has most of the structural characteristics o ...200717174571
differences in enzyme activities between two species of hematodinium, parasitic dinoflagellates of crustaceans.parasitic dinoflagellates of the genus hematodinium infect several commercially important decapod crustaceans. different species of hematodinium have different levels of virulence in their respective hosts. enzyme activities were studied from two species of hematodinium, one isolated from the norway lobster (nephrops norvegicus) and the other from the american blue crab (callinectes sapidus). we report the identification of differences in secretion of acid phosphatase (ap) and leucine arylamidas ...200717156792
the mitochondrial manganese superoxide dismutase gene in chinese shrimp fenneropenaeus chinensis: cloning, distribution and expression.manganese superoxide dismutase (mnsod) plays an important role in crustacean immune defense reaction by eliminating oxidative stress. knowledge on mnsod at molecular level allows us to understand its regulatory mechanism in crustacean immune system. a novel mitochondrial manganese superoxide dismutase (mmnsod) was cloned from hepatopancreas of chinese shrimp fenneropenaeus chinensis by 3' and 5' rapid amplification of cdna ends (race) pcr. the full-length cdna consists of 1185bp with a 660bp ope ...200717097141
identification and developmental expression of mrnas encoding crustacean cardioactive peptide (ccap) in decapod crustaceans.full-length cdnas encoding crustacean cardioactive peptide (ccap) were isolated from several decapod (brachyuran and astacuran) crustaceans: the blue crab callinectes sapidus, green shore crab carcinus maenas, european lobster homarus gamarus and calico crayfish orconectes immunis. the cdnas encode open reading frames of 143 (brachyurans) and 139-140 (astacurans) amino acids. apart from the predicted signal peptides (30-32 amino acids), the conceptually translated precursor codes for a single co ...200616985202
metal concentrations in blue crab (callinectes sapidus) and mullet (mugil cephalus) in iskenderun bay, northern east mediterranean, turkey. 200616977519
expression profiles of na+,k+-atpase during acute and chronic hypo-osmotic stress in the blue crab callinectes sapidus.during acclimation to dilute seawater, the specific activity of na+,k+-atpase increases substantially in the posterior gills of the blue crab callinectes sapidus. to determine whether this increase occurs through regulation of pre-existing enzyme or synthesis of new enzyme, mrna and protein levels were measured over short (<24 h) and long (18 days) time courses. na+,k+-atpase expression, both mrna and protein, did not change during the initial 24-h exposure to dilute seawater (10 ppt salinity). ...200616946242
immune defense reduces respiratory fitness in callinectes sapidus, the atlantic blue crab.crustacean gills function in gas exchange, ion transport, and immune defense against microbial pathogens. hemocyte aggregates that form in response to microbial pathogens become trapped in the fine vasculature of the gill, leading to the suggestion by others that respiration and ion regulation might by impaired during the course of an immune response. in the present study, injection of the pathogenic bacterium vibrio campbellii into callinectes sapidus, the atlantic blue crab, caused a dramatic ...200616946241
a reaction-diffusion analysis of energetics in large muscle fibers secondarily evolved for aerobic locomotor function.the muscles that power swimming in the blue crab, callinectes sapidus, grow hypertrophically, such that in juvenile crabs the cell diameters are <60 microm, whereas fibers of the adult crabs often exceed 600 microm. thus, as these animals grow, their muscle fibers greatly exceed the surface area to volume ratio and intracellular diffusion distance limits of most cells. previous studies have shown that arginine phosphate (ap) recovery in the anaerobic (light) fibers, which demonstrate a fiber siz ...200616943501
accumulation of organic and inorganic contaminants in shellfish collected in estuarine waters near pensacola, florida: contamination profiles and risks to human consumers.we conducted a screening level assessment of contaminants in blue crabs (callinectes sapidus) and oysters (crassostrea virginica) from bays and bayous in the pensacola, fl area. tissue samples were analyzed for 17 dioxins/furans, 12 dioxin-like pcb (dl-pcbs) congeners, mercury, and various metals. contaminant levels were compared to screening values (sv) calculated using u.s. epa recommendations for establishing consumption advisories. all sampling locations exceeded the sv (0.098pgg(-1)) for di ...200716872729
clamming up: environmental forces diminish the perceptive ability of bivalve prey.the lethal and nonlethal impacts of predators in marine systems are often mediated via reciprocal detection of waterborne chemical signals between consumers and prey. local flow environments can enhance or impair the chemoreception ability of consumers, but the effect of hydrodynamics on detection of predation risk by prey has not been investigated. using clams as our model organism, we investigated two specific questions: (1) can clams decrease their mortality by responding to predators? (2) do ...200616869434
expression of crustacean (callinectes sapidus) molt-inhibiting hormone in escherichia coli: characterization of the recombinant peptide and assessment of its effects on cellular signaling pathways in y-organs.a neuropeptide, molt-inhibiting hormone (mih), negatively regulates the synthesis of ecdysteroid molting hormones by crustacean y-organs. we report here the expression of blue crab (callinectes sapidus) mih in escherichia coli. bacteria were transformed with an expression plasmid containing a cdna insert encoding mih. after induction of protein synthesis, recombinant mih (recmih) was detected in the insoluble fraction of cell lysates. the insoluble recmih was refolded and purified by reversed-ph ...200616790313
a comparison of blue crab and bivalve delta15n tissue enrichment in two north carolina estuaries.stable isotope analyses (delta(15)n) were used to examine invertebrate tissue enrichment in two north carolina estuaries with differing amounts of nutrient loading. bivalves collected from a nutrient sensitive estuary yielded a significant difference in mean nitrogen isotopic composition of tissue (10.4 per thousand+/-0.82; n=66) compared to bivalves collected from a less nutrient sensitive estuary (6.4 per thousand+/-0.63; n=45). similarly, blue crabs from nutrient sensitive sites had a nitroge ...200716714075
when r-selection may not predict introduced-species proliferation: predation of a nonnative oyster.predicting outcomes of species introductions may be enhanced by integrating life-history theory with results of contained experiments that compare ecological responses of exotic and analogue native species to dominant features of the recipient environment. an asian oyster under consideration for introduction to the chesapeake bay, usa, the rapidly growing suminoe oyster (crassostrea ariakensis), may not be as successful an invader as its r-selected life history suggests if the trade-off for rapi ...200616711058
et743: chemical analysis of the sea squirt ecteinascidia turbinata ecosystem.the sea squirt ecteinascidia turbinata produces the powerful drug et743. in this study inductively coupled plasma-atomic emission spectroscopy (icp-aes) and matrix assisted laser desorption ionization-mass spectrometry (maldi-ms) are systematically used to measure elemental and molecular species in a florida keys mangrove ecosystem that contains the sea squirt. icp-aes is used to measure the concentration of 27 elements down to the parts per billion level in 16 organisms and 3 sediment samples t ...200616644544
effect of salinity on osmoregulatory patch epithelia in gills of the blue crab callinectes sapidus.in euryhaline crabs, ion-transporting cells are clustered into osmoregulatory patches on the lamellae of the posterior gills. to examine changes in the branchial osmoregulatory patch in the blue crab callinectes sapidus in response to change in salinity and to correlate these changes with other osmoregulatory responses, crabs were acclimated to a range of salinities between 10 and 35 ppt. when crabs that had been acclimated to 35 ppt were subsequently transferred to 10 ppt, both the size of the ...200616641518
incremental ecological exposure risks from contaminated sediments in an urban estuarine river.estuaries in urban regions present unique environmental management challenges. ecosystems in urban estuaries are typically impacted by habitat loss and degradation, watershed modification, and nonpoint and point sources of many chemicals. restoring such systems requires an understanding of the relative contribution of various stressors to overall ecological conditions and an understanding of shifting patterns of stress over time. in this article, we present the results of a multiparameter enviro ...200516639904
molecular cloning of a cdna encoding a crustacean hyperglycemic hormone from eyestalk ganglia of the blue crab, callinectes sapidus.crustacean hyperglycemic hormone (chh), a polypeptide with multiple physiological effects, was first identified in the x-organ/sinus gland neurosecretory system of the eyestalks. in studies reported here, we used a pcr-based cloning strategy (rt-pcr followed by 5'- and 3'-race) to clone from blue crab (callinectes sapidus) eyestalk ganglia a cdna (cschh-1) encoding a putative chh preprohormone. sequence analysis revealed the preprohormone included all structural features previously reported for ...200616631756
cloning and characterisation of mitochondrial manganese superoxide dismutase (mtmnsod) from the giant freshwater prawn macrobrachium rosenbergii.a cdna encoding a mitochondrial manganese superoxide dismutase (mtmnsod) was cloned from the hepatopancreas of giant freshwater prawn macrobrachium rosenbergii using reverse transcription polymerase chain reaction (rt-pcr) by degenerate primers. both 3'- and 5'-regions were isolated by rapid amplification of cdna end (race) pcr method. analysis of nucleotide sequence revealed that the mtmnsod full-length cdna consists of 1202bp containing an open reading frame of 654bp, which encodes a protein c ...200616621606
the effects of hypoxia and ph on phenoloxidase activity in the atlantic blue crab, callinectes sapidus.in its natural coastal and estuarine environments, the blue crab, callinectes sapidus, often encounters hypoxia, accompanied by hypercapnia (increased co2) and an associated decrease in water ph. previous studies have shown that exposure to hypercapnic hypoxia (hh) impairs the crab's ability to remove culturable bacteria from its hemolymph. in the present study we demonstrate that the activity of phenoloxidase (po), an enzyme critical to antibacterial immune defense in crustaceans, is decreased ...200616616537
what is molt-inhibiting hormone? the role of an ecdysteroidogenesis inhibitor in the crustacean molting cycle.the in vivo molt-inhibitory effects of the ecdysone biosynthesis inhibitors 3-hydroxy-l-kynurenine and xanthurenic acid were investigated. these ecdysone biosynthesis inhibitors, isolated from the eyestalks of blue crabs (callinectes sapidus), were injected into eyestalk-ablated crayfish (procambarus clarkii). the active factor was found to be species-nonspecific within crabs and crayfish. the seasonal profiles of the xanthurenic acid and ecdysone titers exhibited a staggered relationship. moreo ...198916594067
hard clams (mercenaria mercenaria) evaluate predation risk using chemical signals from predators and injured conspecifics.hard clams, mercenaria mercenaria, are sessile, filter-feeding organisms that are heavily preyed upon by blue crabs, which find their clam prey using chemical cues. clams may evade blue crabs by reducing their pumping (feeding) behavior when a threat is perceived. the purpose of this study was to determine the type of signals that clams use to detect consumers. clams decreased their pumping time in response to blue crabs and blue crab effluent, but not to crab shells, indicating that chemical si ...200616586040
two new species of epistylis (ciliophora: peritrichida) on the blue crab (callinectes sapidus) in the gulf of mexico.two epibiotic peritrichs infested the blue crab, callinectes sapidus, from the gulf of mexico, mississippi, usa. epistylis callinectes n. sp. was isolated from the epipods of maxillipeds, bases of gill-cleaning setae, and gills, and epistylis clampi n. sp. was isolated from the exterior surfaces of the exoskeleton. epistylis callinectes has short, symmetrically and dichotomously branched stalks; its zooid is elongate ovoid and conspicuously longer than the individual stalk branches, measuring 40 ...200616579810
comparative hemolytic activity of vibrio parahaemolyticus and related vibrios.the hemolytic activities of 91 strains of vibrio parahaemolyticus isolated from human diarrheal stools, sea fish, and sea water; 21 suspected v. parahaemolyticus cultures isolated from wound infections; 14 nonpathogenic marine vibrios; and 21 v. parahaemolyticus isolated from moribund blue crabs callinectes sapidus were compared. potentially pathogenic v. parahaemolyticus strains could be differentiated from the related nonpathogenic marine vibrios, because the former hemolyzed hamster, sheep, a ...197016557747
regulation of protein synthesis in y-organs of the blue crab (callinectes sapidus): involvement of cyclic amp.paired y-organs secrete ecdysteroid hormones that control cycles of growth and molting in crustaceans. y-organs are regulated, at least in part, by molt-inhibiting hormone (mih), a polypeptide produced and released by the x-organ/sinus gland complex of the eyestalks. in the present studies, crab (callinectes sapidus) y-organs were incubated in vitro in the presence of [(35)s]methionine, and cyclic nucleotide analogs or experimental agents that influence the camp signaling pathway. in 4-hr incuba ...200616493643
gill area, permeability and na+ ,k+ -atpase activity as a function of size and salinity in the blue crab, callinectes sapidus.juvenile blue crabs, callinectes sapidus, extensively utilize oligohaline and freshwater regions of the estuary. with a presumptively larger surface-area-to-body weight ratio, juvenile crabs could experience osmo- and ionoregulatory costs well in excess of that of adults. to test this hypothesis, crabs ranging over three orders of magnitude in body weight were acclimated to either sea water (1,000 mosm) or dilute sea water (150 mosm), and gill surface area, water and sodium permeabilities (calcu ...200616432886
molecular cloning of a putative receptor guanylyl cyclase from y-organs of the blue crab, callinectes sapidus.crustacean molt-inhibiting hormone (mih), a polypeptide produced by neurosecretory cells in eyestalk ganglia, suppresses the synthesis of ecdysteroid molting hormones by paired y-organs. data from several sources indicate the effects of mih are mediated, at least in part, by a cgmp second messenger. based on these and related findings, our working hypothesis is that the mih receptor is a receptor guanylyl cyclase (rgc). in studies reported here, we used a pcr-based cloning strategy (rt-pcr follo ...200616426608
the utilization of lipovitellin during blue crab (callinectes sapidus) embryogenesis.embryos of the blue crab callinectes sapidus develop in egg sacs carried on the abdomen of the female. they develop over a period of 10-13 days at 28 degrees c and are nutritionally dependent on yolk until they emerge from the egg sacs as free-swimming zoeae. the principal component of blue crab yolk is lipovitellin (lpii), a water-soluble lipoprotein composed of approximately equal amounts of lipid and protein. we followed changes in the concentration of apoproteins of lpii during embryogenesis ...200616406827
effects of eyestalk ablation on carbonic anhydrase activity in the euryhaline blue crab callinectes sapidus: neuroendocrine control of enzyme expression.carbonic anhydrase (ca) activity in the gills of the euryhaline blue crab, callinectes sapidus, was measured in response to acute low-salinity transfer and treatment with eyestalk ablation (esa) in an attempt to elucidate potential regulatory mechanisms of salinity-mediated ca induction. esa alone resulted in an approximate doubling of ca activity in the posterior, ion-transporting gills of crabs acclimated to 35 ppt. transfer of intact crabs to 28 ppt, a salinity at which the blue crab is still ...200616358277
molecular cloning and characterisation of copper/zinc superoxide dismutase (cu,zn-sod) from the giant freshwater prawn macrobrachium rosenbergii.a copper/zinc superoxide dismutase (cu,zn-sod) cdna was cloned from the hepatopancreas of giant freshwater prawn macrobrachium rosenbergii using reverse transcription-polymerase chain reaction (rt-pcr) by degenerate primers. both 3'- and 5'-regions were isolated by the rapid amplification of cdna ends method. analysis of nucleotide sequence revealed that the cu,zn-sod cdna clone consists of 845 bp with an open reading frame of 603 bp encoding a protein of 201 amino acids with a 22 amino acid sig ...200616356736
bdellovibrios in callinectus sapidus, the blue crab.bdellovibrios were recovered from the gill tissue of all of 31 crabs sampled and from all samples of epibiota obtained from the ventral shell surface of 15 crabs. the results suggest that the blue crab is a reservoir for bdellovibrios. the association with crabs may be an important factor in the ecology of the bdellovibrios.199216348706
phylogenetic position of the copepod-infesting parasite syndinium turbo (dinoflagellata, syndinea).sequences were determined for the nuclear-encoded small subunit (ssu) rrna and 5.8s rrna genes as well as the internal transcribed spacers its1 and its2 of the parasitic dinoflagellate genus syndinium from two different marine copepod hosts. syndinium developed a multicellular plasmodium inside its host and at maturity free-swimming zoospores were released. syndinium plasmodia in the copepod paracalanus parvus produced zoospores of three different morphological types. however, full ssu rdna sequ ...200516310746
a review of the parasitic dinoflagellates hematodinium species and hematodinium-like infections in marine crustaceans.parasitic dinoflagellates in the genus hematodinium are important parasites of marine crustacea. outbreaks of these parasites have damaged commercial stocks of norway lobster nephrops norvegicus, snow crab chionoecetes opilio, tanner crab c. bairdi, american blue crab callinectes sapidus, and velvet swimming crab necora puber. species of hematodinium can reach high enough levels to regulate their host populations, but mortalities are also centred on the unfished juveniles and females, hosts not ...200516175968
molecular cloning and characterisation of cytosolic manganese superoxide dismutase (cytmn-sod) from the giant freshwater prawn macrobrachium rosenbergii.a cytosolic manganese superoxide dismutase (cytmn-sod) cdna was cloned from the hepatopancreas of giant freshwater prawn macrobrachium rosenbergii using reverse transcription polymerase chain reaction (rt-pcr) by degenerate primers. both 3'- and 5'-regions were isolated by rapid amplification of cdna end race method. analysis of nucleotide sequence revealed that the cytmn-sod cdna clone consists of 1339 bp with an open reading frame of 858 bp encoding a protein of 286 amino acids. the calculated ...200616154362
the complete mitochondrial genome of the stomatopod crustacean squilla mantis.animal mitochondrial genomes are physically separate from the much larger nuclear genomes and have proven useful both for phylogenetic studies and for understanding genome evolution. within the phylum arthropoda the subphylum crustacea includes over 50,000 named species with immense variation in body plans and habitats, yet only 23 complete mitochondrial genomes are available from this subphylum.200516091132
gill microsomal (na+,k+)-atpase from the blue crab callinectes danae: interactions at cationic sites.euryhaline crustaceans tolerate exposure to a wide range of dilute media, using compensatory, ion regulatory mechanisms. however, data on molecular interactions occurring at cationic sites on the crustacean gill (na+,k+)-atpase, a key enzyme in this hyperosmoregulatory process, are unavailable. we report that na+ binding at the activating site leads to cooperative, heterotropic interactions that are insensitive to k+. the binding of k+ ions to their high affinity sites displaces na+ ions from th ...200516055367
does intracellular metabolite diffusion limit post-contractile recovery in burst locomotor muscle?post-metamorphic growth in the blue crab entails an increase in body mass that spans several orders of magnitude. the muscles that power burst swimming in these animals grow hypertrophically, such that small crabs have fiber diameters that are typical of most cells (<60 microm) while in adult animals the fibers are giant (>600 microm). thus, as the animals grow, their muscle fibers cross and greatly exceed the surface area to volume ratio (sa:v) and intracellular diffusion distance threshold tha ...200516000534
four differentially expressed cdnas in callinectes sapidus containing the rebers-riddiford consensus sequence.decapod crustaceans such as callinectes sapidus, the blue crab, provide unique opportunities to study proteins involved in biomineralization. subsequent to each molt, the previously deposited soft cuticle is calcified while the postecdysial layers are simultaneously deposited and mineralized. though the majority of the exoskeleton hardens, morphologically similar cuticle at the joints, called arthrodial membrane, remains flexible. it seems reasonable that hypodermal cells producing these cuticle ...200515939643
trimeric g proteins in crustacean (callinectes sapidus) y-organs: occurrence and functional link to protein synthesis.crustacean y-organs produce ecdysteroid molting hormones. regulation of ecdysteroidogenesis appears to be complex, involving regulatory ligands (including but not limited to molt-inhibiting hormone, an eyestalk neurohormone) and the capacity of the y-organs to respond to those ligands. available data indicate cell signaling pathways involving camp, cgmp, or both may be involved in regulation of y-organ function. trimeric g proteins link receptor occupancy to regulation of intracellular camp leve ...200515880757
isolation and structure elucidation of feeding deterrent diterpenoids from the sea pansy, renilla reniformis.four new briarane diterpenoids, renillins a-d (1-4), and the known compound renillafoulin c (5) were isolated from the sea pansy, renilla reniformis. the structures and relative stereochemistry were elucidated by the interpretation of spectroscopic data. using laboratory feeding assays, all compounds tested at natural concentrations significantly deterred feeding by the predatory lesser blue crab, callinectes similis, while renillins c (3) and d (4) also deterred feeding by the predatory mummich ...200515844939
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