Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| calcium-induced calcium release mechanism from the sarcoplasmic reticulum in skinned crab muscle fibres. | mechanically skinned skeletal muscle fibres of the crab carcinus maenas have been used to investigate the mechanism of calcium release from the sarcoplasmic reticulum. calcium release has been monitored by the amplitude and kinetics of the tension developed by the fibre. results show that a very low calcium concentration, insufficient to directly activate contractile proteins, induces a release of calcium from the sr. this release is stimulated by low concentrations of caffeine and inhibited by ... | 1986 | 3085951 |
| neurohormonal control of ecdysteroid biosynthesis by carcinus maenas y-organs in vitro, and preliminary characterization of the putative molt-inhibiting hormone (mih). | using simple culture techniques, the effects of neurosecretory tissue, sinus gland-conditioned media, and sinus gland extracts upon the biosynthesis of ecdysteroids by carcinus maenas y-organs in vitro were investigated. the sinus glands were found to be a major source of a factor which profoundly repressed ecdysteroid synthesis and which did not appear to be species-specific within other brachyurans examined (liocarcinus, cancer). it is suggested that the inhibitory factor is produced by the ne ... | 1986 | 3956985 |
| immunochemical and immunocytochemical studies of the crustacean vitellogenesis-inhibiting hormone (vih). | immunochemical investigations, using dot immunobinding assay (dia) and enzyme-linked immunosorbent assay (elisa), and immunocytochemical studies reveal the following new information about crustacean vitellogenesis-inhibiting hormone (vih): (1) the structure of vih is sufficiently different from that of the other sinus gland neuropeptides to allow a selective recognition of vih by polyclonal antibodies. (2) from immunochemical criteria, vih does not seem strictly species specific. the antisera ra ... | 1987 | 3666410 |
| [beta-alanylation, a means for neutralization of histamine in the central nervous system of carcinus maenas]. | histamine neutralization in carcinus maenas is not ensured by oxidation, methylation, or acetylation. after injecting labelled histamine, radioactive carcinine (beta-alanylhistamine), biosynthesized in the central nervous system, rapidly accumulates in the heart. this synthesis is intense and proportional to the amount of histamine injected; on the contrary, it is very low after injecting labelled beta-alanine, whatever the amount injected. ten days after injecting [14c]histamine, the amounts of ... | 1987 | 3121156 |
| [effect of elastic properties of the crab axon sheath on the movement of nerve fibers at the action potential]. | the shear modulus (nu) of single giant axon of the crab carcinus maenas was determined by measuring the axon elastic stretching up to 1-10%. the value obtained for nu (5-7 x 10(3) dn x cm) is more than that for sheaths of reptilian and mammalian red blood cells by 10(4)-10(6) times. proteolysis of the axon sheath by pronase solution (2 mg/ml, 15-20 min) increases the amplitude of axon movement at the action potential by 8-10 times. it is suggested that the collagen fibers, schwann's and connecti ... | 1987 | 3617222 |
| force-sensitive mechanoreceptors of the dactyl of the crab: single-unit responses during walking and evaluation of function. | the activities of individual force-sensitive mechanoreceptors of the dactyl (terminal leg segment) of the crab, carcinus maenas, have been recorded during free walking. these receptors have also been mechanically and electrically stimulated in freely moving animals to directly evaluate their function in locomotion. all force-sensitive mechanoreceptors fired during the stance phase of walking and were silent during swing. receptor discharges showed regular phase relationships to bursts in motor n ... | 1987 | 3585482 |
| single-unit responses and reflex effects of force-sensitive mechanoreceptors of the dactyl of the crab. | this paper examines the responses and reflex effects of force-sensitive mechanoreceptors of the most distal leg segment, the dactyl, of the leg of the crab, carcinus maenas. the goals of these studies are to establish the potential activities and functions of these receptors in posture and locomotion. the responses of force-sensitive mechanoreceptors to imposed mechanical stimuli depended upon their location on the dactyl. a distal group of receptors is located on a specialized region, the dacty ... | 1987 | 3585481 |
| [demonstration of carcinine synthetase, a new enzyme catalysing the metabolism of histamine in the central nervous system of carcinus maenas]. | carcinine biosynthesis was induced in vitro from its two components, beta-alanine and histamine. the reaction was catalyzed by muscle, heart, and cns extracts from carcinus maenas. the specific activity of the enzyme, carcinine synthetase, was 15 times higher in cns than in other organs. only cns extracts induced biosynthesis of carcinine from histidine, and only in the presence of pyridoxal-5'-phosphate. hence the seat of carcinine biosynthesis seems to be the cns. it is highly probable that in ... | 1987 | 3819732 |
| activation of skinned muscle fibers by calcium and strontium ions. | intact and mechanically skinned skeletal muscle fibers of the crab carcinus maenas have been used. the aim of the experiments was to determine the origin of the mechanical activity recorded in intact crab muscle fibers exhibiting an inward strontium current in strontium solution without calcium. to do so, the effect of strontium ions in inducing activation of contractile proteins and calcium release from the sarcoplasmic reticulum has been studied. the properties of the sarcoplasmic reticulum me ... | 1987 | 2440539 |
| elaboration and ultrastructural changes in the pore canal system of the mineralized cuticle of carcinus maenas during the moulting cycle. | two basic structural components are concerned in the elaboration of the pore canal system in the mineralized cuticle of the decapod crab carcinus maenas: tubular cytoplasmic extensions originating from epidermis and vertical fibres. these components are present from the moment the first procuticular materials of the new cuticle are laid down but their organization varies according to a precise schedule during the further moult cycle stages. cytoplasmic extensions form a complicated branching sys ... | 1987 | 18620225 |
| ultrastructural shape and three-dimensional organization of the intracuticular canal systems in the mineralized cuticle of the green crab carcinus maenas. | two main self-contained canal systems are present in the crab mineralized cuticle. the first, or fibre canal system, is constituted by simple, unbranched vertical canals containing axially running fibres in close association with myoepidermal junctions. the second, or pore canal system, is composed of procuticular pore canals and epicuticular channels that prolong the procuticular canals. in opposition to widespread opinion, pore canals make up a three-dimensional branched system extending from ... | 1987 | 18620224 |
| unusual cardioactive peptide (ccap) from pericardial organs of the shore crab carcinus maenas. | an unusual crustacean cardioactive peptide (ccap) from the pericardial organs of the shore crab carcinus maenas has been purified to homogeneity by a two-step reversed-phase hplc procedure. manual microsequencing using the 4-(n,n-dimethylamino)azobenzene 4'-isothiocyanate/phenylisothiocyanate double-coupling technique and automated gas-phase sequencing of the oxidized peptide revealed that ccap is a nonapeptide (m(r) 957) of the sequence pro-phe-[unk]cys-asn-ala-phe-thr-gly-cys-nh(2). we have co ... | 1987 | 16593803 |
| signaled avoidance in the eye withdrawal reflex of the green crab. | learning in a signaled avoidance procedure was studied in the eye withdrawal reflex of the green crab, carcinus maenas. a puff of air to the eye, which causes eye retraction, was used as the unconditioned stimulus (us). a mild vibration on the carapace, which has no effect on untrained animals, was used as a warning (conditioned) stimulus (cs). eye withdrawal during the cs led to the omission of the otherwise scheduled us. acquisition was rapid, reaching about 75% avoidance after 30 trials. exti ... | 1988 | 16812569 |
| classical conditioning of the eye withdrawal reflex in the green crab. | eye withdrawal in the green crab, carcinus maenas was conditioned by pairing a mild vibration to the carapace as a conditioned stimulus (cs) with a puff of air to one of the eyes as an unconditioned stimulus (us). animals subjected to repeated pairings showed an increased probability of eye retraction during cs presentation. significantly less responding was found in several control groups subjected to backward conditioning, unpaired stimuli, stimuli alone, or simply time in the apparatus. altho ... | 1988 | 3411360 |
| localization of pigment-dispersing hormone (pdh) immunoreactivity in the central nervous system of carcinus maenas and orconectes limosus (crustacea), with reference to fmrfamide immunoreactivity in o. limosus. | by use of antisera raised against synthetic pigment-dispersing hormone (pdh) of uca pugilator and fmrfamide, the distribution of immunoreactive structures in the central nervous system (cns) of carcinus maenas and orconectes limosus was studied by light microscopy. in both species, a total of 10-12 pdh-positive perikarya occur amongst the anterior medial, dorsal lateral and angular somata of the cerebral ganglion (cg). in c. maenas, one pdh-perikaryon was found in each commissural ganglion (cog) ... | 1988 | 3416337 |
| after-effects following responses of a muscle stretch receptor of the shore crab, carcinus maenas. | stretch evoked responses of the thoracic-coxal muscle receptor organ in the crab are shown to be time dependent. thus, by varying the interstretch interval, the duration of the t fibre dynamic component of the response to a ramp-and-hold stretch was found to be directly related to the inter-stretch interval. with long interstretch intervals (e.g. 10 min), the t fibre dynamic component of the response to stretch was undistinguishable from the response when pre-conditioned with stimulation of the ... | 1988 | 3380357 |
| effects of anions, ca2+, mg2+, and aliphatic alcohols on the reaction of hemocyanin with cyanide. | the reaction between carcinus maenas hemocyanin and cyanide has been used for probing protein conformation in the presence of perturbants such as various anions, cations (ca2+, mg2+), and aliphatic alcohols. the kinetic parameters of the reaction are strongly affected by these agents, suggesting that the induced conformational modifications change the reactivity of the active site toward exogenous ligands. different patterns are observed according to the perturbant used. as indicated by the math ... | 1988 | 3355164 |
| neural control of ventilation in the shore crab, carcinus maenas. ii. frequency-modulating interneurons. | 1. we have identified a class of nonspiking interneurons which can control the frequency of ventilation in a graded manner. these frequency modulating interneurons (fmis) also receive synaptic inputs in-phase with the ventilatory motor output providing a functional positive feedback loop in the ventilatory system. the class of fmis is composed of three morphologically and physiologically distinct interneurons, fmi1, fmi2 and fmi3. 2. depolarization of fmi1 increases the rate of ventilation, whil ... | 1988 | 3351789 |
| cloning and sequence analysis of cdna for precursor of a crustacean hyperglycemic hormone. | crustacean hyperglycemic hormone (chh) from carcinus maenas, a 72 amino acid neuropeptide, originates in neurosecretory perikarya in the eyestalk ganglia. poly (a)rna was isolated from these perikarya and a cdna library was prepared. screening of 20,000 clones with a 26-mer oligonucleotide, corresponding to a partial sequence of chh, yielded one positive clone with an insert of approximately 2,000 bp, which contained the complete coding sequence for a pre-pro chh. this precursor consists of a pu ... | 1989 | 2806562 |
| electrogenic sodium-proton exchange in membrane vesicles from crab (carcinus maenas) gill. | plasma membrane vesicles from na+-absorbing posterior gills of the green crab carcinus maenas were shown to contain a na+-h+ antiporter sensitive to amiloride (ki = 280 mumol/l), using a fluorometric assay based on acridine orange. lithium was found to support li+-h+ exchange, giving michaelis-menten kinetics (k0.5 = 20 mmol/l) and a hill coefficient of 1.32 +/- 0.06, indicating a stoichiometry of 1 li+:1 h+. the stoichiometry of na+-h+ exchange, however, appeared to be 2 na+:1 h+. the dependenc ... | 1989 | 2552847 |
| amino acid sequence of the crustacean hyperglycemic hormone (chh) from the shore crab, carcinus maenas. | crustacean hyperglycemic hormone (chh) was isolated from sinus glands of carcinus maenas, and its primary structure was determined by manual microsequencing, using the dabitc-pitc double-coupling method. the neurohormone consists of 72 amino acid residues (8524 da). three disulfide bridges are present and both the n- and c-terminus are blocked. chh does not show significant sequence homology to any known peptide hormone or protein. | 1989 | 2792364 |
| hemolymph oxygen transport during environmental hypoxia in the shore crab, carcinus maenas. | pre- and postbranchial blood was sampled from crabs, carcinus maenas, in control normoxic conditions and after 3, 24 and 72 hours exposure to hypoxic water (pwo2 = 30 torr) at 15 degrees c. oxygen partial pressures, ph and the concentrations of l-lactate, urate and hemocyanin were measured and an in vitro relationship between p50 and ph was determined on a pooled sample for each series, allowing an estimation of the average in vivo oxygen affinity. in separate experiments, in vitro additions of ... | 1989 | 2781169 |
| nonspiking interneurons in the ventilatory central pattern generator of the shore crab, carcinus maenas. | eight nonspiking interneurons were identified that are elements of the central pattern generator controlling ventilation in the shore crab, carcinus maenas. intracellular recordings from these neurons in an isolated ganglion preparation revealed that these cells exhibit large amplitude oscillations in their membrane potentials, which are in-phase with the ventilatory motor pattern. these oscillations are present during the expression of the two distinct ventilatory motor output patterns correspo ... | 1989 | 2754049 |
| learning and the role of cue reinforcement in the shell cracking behaviour of the shore crab: carcinus maenas (l). | the shell-cracking behaviour of carcinus maenas as it fed on littorina littorea has been described. of the various behavioural tactics employed, sawing, drilling/prizing, cutting/crushing and poking were found to be most frequently used. the establishment of a puncture or crack on the winkle shell while harvesting the prey served as an additional cue landing to (1) higher shell-cracking activity per unit time and (2) more frequent and directional inter change or behavioural tactics. analyses of ... | 1989 | 24897673 |
| ultrastructural changes in the gill epithelium of the green crab carcinus maenas in relation to the external salinity. | observation of semi-thin and ultrathin sections performed in the gills of green crabs (carcinus maenas) kept in 100% and in dilute 30% sea water respectively reveals marked differences between the six anterior and the three posterior pairs of gills. the anterior gill lamellae are almost entirely lined by a thin pavement epithelium (0.9 to 3 mum thick) which does not undergo any noticeable change when crabs are acclimated from full to dilute sea water. this supports the view it is chiefly involve ... | 1989 | 18620265 |
| farnesylacetone, a sesquiterpenic hormone of crustacea, inhibits electron transport in isolated rat liver mitochondria. | farnesylacetone (c18 h30 0) is a male hormone extracted from the androgenic gland of crab, carcinus maenas. appropriate enzymatic assays, as well as spectrophotometric studies, indicate that micromolar concentrations of farnesylacetone interact with the electron transport pathway of rat liver mitochondria. by the use of artificial electron donors and electron acceptors, it is shown that farnesylacetone immediately inhibits the electron transfer within complex i (nadh ubiquinone reductase activit ... | 1989 | 2561085 |
| profilicollis botulus (van cleave, 1916) from diving ducks and shore crabs of british columbia. | adults of profilicollis botulus were found in 6 species of diving ducks in british columbia including 3 new hosts: common goldeneye, bucephala clangula (l.); barrow's goldeneye, b. islandica (gmelin); and greater scaup, aythya marila (l.). the identification of the species was verified by the examination of co-types and specimens from eider ducks, somateria mollissima (l.), from scotland and oldsquaw, clangula hyemalis (l.), from new brunswick. cystacanths from the hairy shore crab, hemigrapsus ... | 1989 | 2918442 |
| ultrastructural study on the spermiogenesis and spermatozoon of the metacercariae of microphallus primas (digenea), a parasite of carcinus maenas. | the thread-like spermatozoon of the crab parasite microphallus primas was studied by electron microscopy. a survey of the head region of the spermatozoon reveals three features hitherto unknown in platyhelminthes spermatozoa. the first is the aberrant inclusion of the nucleus within one of the two axonemes, limited to the head end region. the second is the coexistence, in the same axoneme, of two patterns, 9 + 0 (doublets without dynein arms) and 9 + "1". the third is the presence of a layer of ... | 1990 | 2310565 |
| lever-press conditioning in the crab. | an operant chamber has been developed for studying lever-press conditioning in the green crab carcinus maenas. in one series of experiments, animals were presented with a single bar and were reinforced with food for every bar press. performance increased over time and high rates of responding were observed after 2 days of training. the response rate was always higher than that for a yoked (noncontingent) control group. when the contingencies were switched, the animals adjusted to the new conditi ... | 1990 | 2255730 |
| gamma-aminobutyric acid-inhibitory motor innervation of leg muscles of the shore crab. | the inhibitory motor innervation of a crustacean leg was studied in the crab, carcinus maenas. in in vitro preparations of the central nervous system and the proximal leg nerves, motor nerve recordings demonstrate the presence of a single common inhibitory motor neuron which elicits picrotoxin-sensitive inhibitory junction potentials in a distal leg muscle, the accessory flexor. this inhibitor is the common inhibitor (ci). immunohistochemical detection of the inhibitory motor neuron neurotransmi ... | 1990 | 12106056 |
| amino acid sequence of putative moult-inhibiting hormone from the crab carcinus maenas. | putative moult-inhibiting hormone (mih) was isolated from sinus glands of the shore crab carcinus maenas, and its primary structure determined by automated edman degradation of endoproteinase derived peptide fragments. mih is a 78 residue neuropeptide (deduced molecular mass 9181 da) with three disulphide bridges and unblocked n- and c-termini. mih shows some homology to the crustacean hyperglycemic hormone (chh) neuropeptide family. however, consideration of the roles of various members of this ... | 1991 | 1679945 |
| effects of dopamine and acclimation to reduced salinity on the concentration of cyclic amp in the gills of the green crab, carcinus maenas (l). | injection of 10(-5) m dopamine into adult green crabs increased the concentration of cyclic amp (camp) in all gills tested. short-term acclimation (24 hr) of crabs to 40% seawater (sw) also increased the camp content of the posterior gills as compared to controls, an effect similar to that seen with injection of dopamine. however, when crabs were acclimated to reduced salinity for 2 weeks, the concentration of camp in the gills was not statistically different from that of gills from crabs in 100 ... | 1991 | 1652531 |
| isolation, sequence analysis, and physiological properties of enkephalins in the nervous tissue of the shore crab carcinus maenas l. | [leu]- and [met]enkephalin from thoracic ganglia of the shore crab carcinus maenas have been purified to homogeneity by a reversed-phase hplc procedure. automated gas-phase sequencing revealed a primary structure identical with that of enkephalins from vertebrates. the immunoreactive material in different parts of the nervous system of c. maenas was measured by ria. isolated crustacean [leu]enkephalin shows physiological properties identical to synthetic [leu]enkephalin in our bioassay. the enke ... | 1991 | 11607217 |
| in ovo cultivation of microphallus primas (trematoda: microphallidae) metacercariae to ovigerous adults and the establishment of the life-cycle in the laboratory. | this investigation reports for the first time the establishment of a trematode life-cycle in the laboratory using in ovo cultivation of the adult stage. microphallus primas metacercarial cysts were removed from carcinus maenas crabs and chemically excysted. using a modification of the technique developed by fried (1962) the released metacercariae were grown in fertile hen's eggs to ovigerous adult flukes. these were removed from the under surface of the chorio-allantoic membrane of chick embryos ... | 1991 | 1780184 |
| fine structure of the neurohemal sinus gland of the shore crab, carcinus maenas, and immuno-electron-microscopic identification of neurosecretory endings according to their neuropeptide contents. | the sinus gland of the shore crab, carcinus maenas, is a compact assembly of interdigitating neurosecretory axon endings abutting upon the thin basal lamina of a central hemolymph lacuna. four types of axon endings are distinguishable by the size distribution, shape, electron density and core structure of their neurosecretory granules. one additional type of axon ending is characterized by electron-lucent vacuoles and vesicles. the axon profiles are surrounded by astrocyte-like glial cells. vari ... | 1992 | 1423493 |
| biosynthesis of eicosanoids by blood cells of the crab, carcinus maenas. | blood cells from the crab, carcinus maenas, stimulated with calcium ionophore a23187, in the presence of exogenous fatty acid, produced cyclooxygenase, lipoxygenase and monooxygenase derivatives of eicosatetraenoic (20:4(n - 6)) and eicosapentaenoic (20:5(n - 3)) acids. isolation, identification and quantification of these products was achieved using chiral and reverse phase-high performance liquid chromatography, gas-chromatography, radioimmunoassay and gas chromatography-mass spectrometry. the ... | 1992 | 1543736 |
| structural organization of two fast, rhythmically active crustacean muscles. | the organization of the flagellum abductor muscle and of a scaphognathite levator muscle of the green crab, carcinus maenas, has been compared quantitatively using light and electron microscopy. these muscles are rhythmically active at relatively high frequencies and for long durations. fibers of both muscles are interconnected to form fascicles of 50 or more fibers within which there is cytoplasmic continuity. a single muscle is made up of 8-12 fascicles. individual fibers consist of a peripher ... | 1992 | 1571968 |
| [characterization of secondary vitellin in the crustacean brachyura carcinus maenas]. | the secondary vitellin was chromatographically purified and characterized in the crab, carcinus maenas. it was a lipoglycoprotein of molecular weight 500,000. after dissociation, we observed two major sub units (82,000 and 72,000, respectively), and many lighter minor fractions. these results are compared with those described for some other crustacea. | 1992 | 1600463 |
| structure and possible functions of the calcospherite-rich cells (r* cells) in the digestive gland of the shore crab carcinus maenas. | r*-cells of the digestive gland of carcinus maenas have been investigated functionally and morphologically. a comparison of the capacity of separated cell suspensions to synthesize glycogen gave support to the hypothesis that r and r* cells belong to the same cell line. the unexpected observation of r* cells in gastric juice suggests that their release could represent a mode of redistribution of carbohydrate stores when the feeding activity of the crab is lower. under electron microscopy, the ca ... | 1992 | 1310440 |
| molecular cloning of crustacean pigment dispersing hormone precursor. | the cdna encoding the precursor of the pigment dispersing hormone (pdh) of the shore crab, carcinus maenas, was isolated and sequenced. the precursor consists of a putative 22 amino acid signal peptide, a putative 33 residue peptide of unknown function, and the 18 amino acid mature pdh, followed by a gly residue which serves as a possible amide donor. the deduced mature pdh amino acid sequence is identical to those of uca pugilator and cancer magister, previously determined by edman degradation. | 1992 | 1282803 |
| isolation of a neuropeptide from locust corpus cardiacum which influences ileal transport. | 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 i ... | 1992 | 1487715 |
| chromatographic analysis of low-molecular-mass copper-binding ligands from the crab species scylla serrata and portunus pelagicus. | two copper-binding proteins and a zinc-binding ligand were isolated from the hepatopancreas of the crab portunus pelagicus. the copper-binding proteins behave similarly to those from the crabs carcinus maenas and scylla serrata, and were shown to be metallothioneins. reversed-phase high-performance liquid chromatographic (hplc) analysis confirmed the relative purity of both proteins with only cross-contamination between the two different forms of metallothioneins, and offers a good method to sep ... | 1992 | 1618990 |
| quantification, immunoaffinity purification and sequence analysis of a pigment-dispersing hormone of the shore crab, carcinus maenas (l.). | 1. a sensitive sandwich-elisa for pigment-dispersing hormone (pdh) with a detection limit of approximately 5 fmol per well has been developed using primary igg and secondary biotinylated igg fractions from an antiserum against beta-pdh and streptavidin-peroxidase conjugate for detection. 2. elisa determinations in different parts of the central nervous system of the shore crab carcinus maenas revealed maximum levels of 15.1 pmol immunoreactive pdh in the two eyestalk ganglia of one crab, 3.6 pmo ... | 1993 | 8472537 |
| the binding of cd(ii) to the hemocyanin of the mediterranean crab carcinus maenas. | the interaction of carcinus hemocyanin with cd(ii) was studied. the incubation of the apoprotein with the metal yields a derivative containing 1 g-at. of edta-stable cd(ii) per 75 kda. spectroscopic data ruled out cd(ii) coordination to tryptophan or cysteine residues. the optical activity and fluorescence properties of the protein are affected by cd(ii) binding and indicate a rearrangement of tryptophan residues. the poor cd(ii) binding to the oxy-form and the resistance of cd(ii)-hemocyanin to ... | 1993 | 8470909 |
| changes in the brain levels of gaba and related amino acids in anoxic shore crab (carcinus maenas). | the effects of anoxia on the brain concentrations of gamma-aminobutyric acid (gaba), glutamate, aspartate, glutamine, alanine, and taurine were measured in the shore crab (carcinus maenas) and compared with data previously obtained from anoxia-tolerant vertebrates. c. maenas was found to survive 12 h in nitrogen-bubbled water. the changes found in brain amino acid levels were strikingly similar to those seen in anoxia-tolerant vertebrates. thus, during anoxia, the brain of c. maenas displayed co ... | 1993 | 8097386 |
| autoradiographic localization of opioid binding sites combined with immunogold detection of leu-enkephalin, crustacean hyperglycaemic hormone and moult inhibiting hormone at the electron microscopic level in the sinus gland of the shore crab, carcinus maenas. | double labelling experiments were performed on the same tissue section at the electron microscopic level, in order to show the involvement of the opioid leucine-enkephalin (leu-enk) in the modulation of crustacean hyperglycaemic hormone (chh) mobilization. both neuropeptides were stored in distinct axon terminals of the sinus gland of carcinus maenas. a post-embedding immunogold cytochemical technique for leu-enk, chh and the chh neurohormone related moult inhibiting hormone (mih) was combined w ... | 1993 | 8392990 |
| an x-ray absorption near edge structure spectroscopy study of metal coordination in co(ii)-substituted carcinus maenas hemocyanin. | high-resolution x-ray absorption near edge structure spectroscopy was used to characterize the metal sites in three different cobalt-substituted derivatives of carcinus maenas hemocyanin (hc), including a mononuclear cobalt, a dinuclear cobalt and a copper-cobalt hybrid derivative. co(ii) model complexes with structures exemplifying octahedral, trigonal bipyramidal, pseudo-tetrahedral, and square planar geometries were also studied. the results provide structural information about the metal bind ... | 1993 | 8312502 |
| effects of crustacean hyperglycemic hormones from carcinus maenas and orconectes limosus on blood and muscle glucose and glycogen concentration of chasmagnathus granulata. | the effects of purified crustacean hyperglycemic hormones (chh) from carcinus maenas or orconectes limosus, and of eyestalk extract of chasmagnathus granulata on the blood and muscle glucose and glycogen concentration of chasmagnathus granulata were investigated. different groups of animals (at least 7 animals per group) were injected with chh from either c. maenas or o. limosus chh dissolved in saline (16 pmol/animal) or crude eyestalk extract of c. granulata (1 eyestalk equivalent/animal). all ... | 1993 | 8136730 |
| molecular cloning of crustacean putative molt-inhibiting hormone (mih) precursor. | a cdna encoding the complete precursor of the putative molt-inhibiting hormone (mih) of the shore crab, carcinus maenas, was isolated and sequenced. the precursor consists of a putative 35 amino acid signal peptide and the 78 amino acid mature mih. the deduced mih amino acid sequence is in complete agreement with the sequence previously determined by edman degradation. in situ hybridization revealed mih-expression in a subpopulation of large neurosecretory perikarya of the medulla terminalis x-o ... | 1993 | 8224217 |
| the involvement of a cyclic nucleotide secondary messenger system in the prophenoloxidase cascade of the crustacean, carcinus maenas. | 1993 | 8132040 | |
| molecular cloning of crustacean red pigment concentrating hormone precursor. | a cdna encoding the precursor of the red pigment concentrating hormone (rpch) of the shore crab, carcinus maenas, was isolated and sequenced. the predicted preprohormone sequence consists of a putative 25 amino acid signal peptide, the eight amino acid rpch sequence followed by a gly as amide donor, a dibasic processing site and a 74 residue peptide of unknown function, referred to as rpch-precursor-related peptide (rprp). in in situ hybridisation experiments, the rpch gene transcript could be l ... | 1993 | 8373416 |
| isolation and identification of a cardioactive peptide from tenebrio molitor and spodoptera eridania. | we isolated several cardioactive peptides from extracts of whole heads of the mealworm, tenebrio molitor, and the southern armyworm, spodoptera eridania, using a semi-isolated heart of manduca sexta for bioassay. we have now isolated from each species the peptide with the strongest effect on rate of contraction of the heart. the peptides were identified using micro edman sequencing and mass spectrometric methods. this cardioactive peptide has the same primary structure from both species: pro-phe ... | 1993 | 8129851 |
| crustacean cardioactive peptide in the sphinx moth, manduca sexta. | the isolation, identification, and actions of crustacean cardiactive peptide (ccap) have been examined in the sphinx moth manduca sexta. a sensitive and specific enzyme-linked immunosorbent assay (elisa) was used to quantify ccap-like immunoreactivity in the nervous system. the ccap-like immunoreactivity from the abdominal cns was then purified, and its sequence was ascertained by amino acid analysis, mass spectral analysis, and hplc. these studies showed that the nervous system of m. sexta cont ... | 1993 | 8234018 |
| demonstration of co-resistance of haemonchus contortus to ivermectin and moxidectin. | studies were conducted to determine whether organisms which are resistant to ivermectin are also resistant to moxidectin. the mechanisms of action of moxidectin and ivermectin were compared by measuring the changes in membrane conductance they induced in leg muscle fibres of the common shore crab (pachygrapsus crassipes) by using standard micro-electrode techniques. meriones unguiculatus (jirds) were infected with ivermectin-resistant or -susceptible strains of haemonchus contortus, treated with ... | 1993 | 8362470 |
| molecular cloning of two pigment-dispersing hormone (pdh) precursors in the blue crab callinectes sapidus reveals a novel member of the pdh neuropeptide family. | a cdna library was established from the eyestalk ganglia of the blue crab callinectes sapidus. screening resulted in the isolation of a clone (497 bp excluding poly(a) tail) which encodes a beta-pdh previously found in several crustacean species. it displays high sequence similarity with a clone isolated from an eyestalk cdna library of the shore crab carcinus maenas, indicating the close phylogenetic relationship of both species. a second clone (414 bp exclusive of the poly(a) tail) encodes a n ... | 1994 | 7999056 |
| membrane-associated carbonic anhydrase from the crab gill: purification, characterization, and comparison with mammalian cas. | carbonic anhydrase (ca) was purified from the gills of the shore crab carcinus maenas using affinity chromatography and hplc. the predominantly membrane-bound ca was found to share several features with mammalian ca iv. its apparent molecular weight of 36 kda was reduced to 33 kda by treatment with pngase f, suggesting that crab ca is a glycoprotein with one n-linked oligosaccharide chain. more than half of the membrane-bound crab ca was released from membranes by treatment with a phosphatidylin ... | 1994 | 8037456 |
| opsonic activity of cell adhesion proteins and beta-1,3-glucan binding proteins from two crustaceans. | a beta-1,3-glucan binding protein (beta gbp) from the shore crab carcinus maenas was purified from plasma by precipitation of the protein at low ionic strength. the protein had a molecular mass of 110 kda, and was shown to affinity precipitate with laminarin, a soluble beta-1,3-glucan, and to cross-react with an antiserum directed toward beta gbp from the crayfish pacifastacus leniusculus. also, a protein from the haemocytes of c. maenas with a molecular mass of 80 kda was found to mediate cell ... | 1994 | 8050614 |
| purification and characterization of a cadmium-induced metallothionein from the shore crab carcinus maenas (l.). | two metallothionein variants were purified from the midgut gland of crabs (carcinus maenas) exposed to a high cadmium concentration (2 p.p.m.). one of the variants was purified from crabs exposed to a low cadmium concentration (0.5 p.p.m.). the purification method involved acetone precipitation, gel filtration and reversed-phase h.p.l.c. the complete amino acid sequences of both variants have been elucidated by m.s. and automated sequence analysis on s-methylated proteins or fragments produced b ... | 1994 | 8110201 |
| an oxygenation-sensitive dye binding to carcinus maenas hemocyanin. | the interaction of 4',6-diamidino-2-phenylindole (dapi) with carcinus maenas hemocyanin has been investigated by steady state fluorescence, dynamic fluorescence and circular dichroism measurements. the dye binds to apohemocyanin (without copper) as well as to oxygenated hemocyanin and to deoxygenated hemocyanin with very similar affinities (kd approximately equal to 1 microm ) and number of binding sites (one per subunit). in contrast, the fluorescence quantum yield enhancement of dapi bound to ... | 1994 | 17020829 |
| calcium transport in gill plasma membranes of the crab carcinus maenas: evidence for carriers driven by atp and a na+ gradient. | a procedure was developed for the preparation of inside-out vesicles from plasma membranes isolated from the branchial epithelium of the green shore crab carcinus maenas (l.). procedures normally applied to fish branchial epithelium required the introduction of an additional hypotonic shock to obtain a preparation containing 22% inside-out vesicles, 33% right-side-out vesicles and 45% leaky membrane fragments. in such membrane preparations, the first direct evidence for uphill (against a [ca2+] ... | 1994 | 7964408 |
| involvement of camp and cgmp in the mode of action of molt-inhibiting hormone (mih) a neuropeptide which inhibits steroidogenesis in a crab. | in crustaceans, production of molting hormones (or ecdysteroids) by the molting glands (y-organs; yo), is under negative control exerted by a neuropeptide, the molt-inhibiting hormone (mih). mih of the crab carcinus maenas inhibits in vitro steroidogenesis of basal (intermolt crab) or activated (premolt crab) yo. mih inhibits secretion of the two ecdysteroids synthesized by crab yo, ecdysone (e) secreted throughout the molting cycle, and 25-deoxyecdysone (25de), secreted during the premolt perio ... | 1994 | 7523205 |
| cardiac performance in semi-isolated heart of the crab carcinus maenas. | a semi-isolated, in situ heart preparation of the shore crab, carcinus maenas, supported by its alary ligaments, pumps vigorously for hours at a mean heart rate of 49.7 beats/min and cardiac output of 30 ml.kg-1.min-1. these hearts show no adaptive responses to changes in pericardial sinus pressure, outflow resistance, or afterload. direct perfusion-induced stretch of the heart wall causes increases in contractile force but minimal changes in heart rate. stroke work and power are lower than comp ... | 1994 | 8160871 |
| degeneration of afferent neurons and long-term stability of the ventilatory central pattern generator in chronically deafferented crabs. | 1. the effects of chronic deafferentation, 3-180 days, are tested on the function and morphology of the crab (carcinus maenas) ventilatory central pattern generator (cpgv). almost all afferent axons are carried in the mixed sensory/motor levator nerve. the ability to speed the cpgv cycle rate by stimulating this nerve (wilkens and dicaprio 1994) decreases as the afferent neurons degenerate. stimulation of the levator nerve eliminates motor units from the output even after 60 days of deafferentat ... | 1994 | 8145191 |
| effects of scaphognathite nerve stimulation on the acutely deafferented crab ventilatory central pattern generator. | 1. sensory axons from crab (carcinus maenas) scaphognathites enter the thoracic ganglion primarily via the lnb branch of the levator nerve. the lna branch of the levator nerve and the depressor nerve each contain relatively few sensory axons. 2. acutely deafferented ventilatory central pattern generators show a free running burst rate which is lower than that observed in intact crabs. electrical stimulation of the levator nerve, or of its lnb branch, increases the burst rate in a frequency depen ... | 1994 | 8145190 |
| molecular cloning and sequence analysis of a cdna encoding a molt-inhibiting hormone-like neuropeptide from the white shrimp penaeus vannamei. | the x-organ of the eyestalk in crustaceans is a source of neurosecretory peptides. total rna was isolated from x-organs of the white shrimp penaeus vannamei and used to clone a cdna encoding a molt-inhibiting hormone-like (mih-like) neuropeptide by the 3' and 5' rapid amplification of cdna ends (race) method. sequence analysis of the 470-bp cdna reveals a 306-bp open reading frame and a 164-bp 3' untranslated region. the deduced polypeptide consists of a 72-amino acid mature peptide and a 30-ami ... | 1994 | 8055060 |
| contractile properties of a high-frequency muscle from a crustacean - mechanical power output | the mechanical power output during oscillatory contraction was determined for the flagellum abductor muscle of the crab carcinus maenas using the work loop technique. measurements were made at 10 hz, which is the normal operating frequency of the muscle. the temperature was 15 °c. increasing the number of stimuli per cycle (given at an interstimulus interval of 3.3 ms) decreased the number of cycles required to reach a work plateau and increased the work per cycle at the plateau to a maximum ... | 1994 | 9317838 |
| neurosecretion of crustacean hyperglycemic hormone evoked by axonal stimulation or elevation of saline k+ concentration quantified by a sensitive immunoassay method | a sandwich-type enzyme-linked immunosorbent assay (elisa) was utilized to quantify crustacean hyperglycemic hormone (as carcinus maenas equivalents) released by single x-organ­sinus gland systems of the crab cardisoma carnifex during continuous perifusion. basal rates of secretion (20­60 pg min-1) were stable for at least 4 h. electrical stimulation (600 stimuli in 5 min) of the axon tract increased secretion two- to threefold, but only if it resulted in neural activity that was propagat ... | 1994 | 9317835 |
| contractile properties of a high-frequency muscle from a crustacean - contraction kinetics | 1. the flagella (small appendages on the maxillipeds) of the crab carcinus maenas beat regularly when active at about 10 hz (15 °c). the beat of a flagellum is due to contraction of a single small muscle, the flagellum abductor (fa). the optimal stimulus frequency for tetanic contraction of the fa was about 200 hz. when the muscle was stimulated at 10 hz with paired stimuli per cycle, the interstimulus interval that maximized peak force was 2­4 ms, which corresponded well to the interspi ... | 1994 | 9317795 |
| contractile properties of a high-frequency muscle from a crustacean - activation patterns in vivo | 1. the flagella of crustaceans are small appendages, borne on the maxillipeds, which beat repetitively when active. flagellar movement is brought about by contraction of a single muscle, the flagellum abductor (fa). 2. the stroke frequency of the flagella of the green crab, carcinus maenas, was about 11 hz at 15 °c and was relatively independent of animal size [frequency is proportional to (animal mass)-0.07], even though scaling considerations suggest that, for constant muscle stress, frequ ... | 1994 | 9317764 |
| fine structure and morphogenesis of the sclerite epicuticle in the atlantic shore crab carcinus maenas. | three basic sublayers are identified in the epicuticle of the mineralised sclerites of the atlantic shore crab carcinus maenas (crustacea, decapoda): the surface coat, the cuticulin layer, and the inner epicuticle. their morphogenesis and subsequent changes are described throughout the moulting cycle in the normal cuticle and the cuticular structures, namely the sensory bristles and epicuticular spines. at first, the cuticulin layer begins to form just after apolysis. this layer is built directl ... | 1995 | 18621310 |
| quantitation of peptide hormone in single cultured secretory neurons of the crab, cardisoma carnifex. | the content of crustacean hyperglycemic hormone (chh) in single cultured neurons of the crab cardisoma carnifex was determined by a sensitive enzyme-linked immunosorbent assay (elisa), using purified chh (1-50 pg) of the crab carcinus maenas as standard. the somata were dissociated from the group of approximately 150 peptidergic neurons that form the x-organ--sinus gland neuroendocrine system. as previously reported, the neurons show immediate regenerative outgrowth in defined culture conditions ... | 1995 | 7553771 |
| structural characterization of mononuclear cu(ii) and its nitrite complex in the active site of carcinus maenas hemocyanin. | the preparation of a mononuclear cu(ii) derivative of carcinus maenas hemocyanin (cu(ii)-hc) and a nitrite complex of the derivative (cu(ii)-hc-no2-) are described. several techniques have been used in their characterization, including x-ray absorption, continuous wave (cw) epr, and electron spin-echo envelope modulation (eseem) spectroscopies. exafs results for cu(ii)-hc indicate the presence of three ligands at 1.99 +/- 0.01 a and a fourth one at 2.26 +/- 0.01 a from the copper. the same coord ... | 1995 | 7849011 |
| cu(ii) coordination in arthropod and mollusk green half-methemocyanins analyzed by electron spin-echo envelope modulation spectroscopy. | hemocyanin (hc) is a dinuclear copper protein that binds oxygen reversibly. the structure of the cu(ii) site in a derivative of hemocyanin known as green half-met (ghm) has been analyzed using the pulsed epr technique of electron spin-echo envelope modulation (eseem) spectroscopy. the derivative, prepared by treating the native protein with nitrite at low ph, contains a mixed-valent binuclear copper center. it was shown through chemical assays and the ligand exchange reaction products identified ... | 1995 | 7849010 |
| a convenient synthesis of 25-deoxyecdysone, a major secretory product of crustacean y-organs and of 2,25-dideoxyecdysone, its putative immediate precursor. | 25-deoxyecdysone, a major secretory product of y-organs of at least several species of crustaceans and the immediate precursor of circulating ponasterone a in these animals, can easily be synthesized from ecdysone. the present four-step procedure involves the formation of a mixture of delta 24,25 and delta 25,26 intermediates which might also be used to prepare a labeled reference compound for metabolic or binding studies. similarly, 2,25-dideoxyecdysone was prepared from 2-deoxyecdysone. these ... | 1995 | 7618184 |
| occurrence of analogues of the myotropic neuropeptide orcokinin in the shore crab, carcinus maenas: evidence for a novel neuropeptide family. | by use of an enzyme immunoassay that was developed for the determination of orcokinin, a myotropic neuropeptide of the sequence nfdeidrsgfgfn from the crayfish, orconectes limosus, immunoreactive material was detected in extracts of thoracic ganglia from the shore crab, carcinus maenas. isolation of the immunoreactive material was achieved by the following steps: 1) prepurification by gel filtration, 2) immunoaffinity chromatography on an anti-orcokinin igg protein-a sepharose column, and 3) rev ... | 1995 | 7716076 |
| molecular cloning of a cdna encoding putative molt-inhibiting hormone from the blue crab, callinectes sapidus. | a cdna library was constructed using poly(a+) rna isolated from eyestalk neural ganglia of the blue crab, callinectes sapidus. the library was screened using a probe generated by pcr based on the published amino acid sequence of molt-inhibiting hormone from the shore crab, carcinus maenas. dna sequence analysis of one positive clone revealed a 339 bp open reading frame encoding a 78-residue putative molt-inhibiting hormone and a 35-residue signal peptide. the deduced amino acid sequence of c. sa ... | 1995 | 7537497 |
| molecular cloning of three distinct cdnas, each encoding a different adipokinetic hormone precursor, of the migratory locust, locusta migratoria. differential expression of the distinct adipokinetic hormone precursor genes during flight activity. | three distinct cdnas encoding the preproadipokinetic hormones i, ii, and iii (prepro-akh i, ii, and iii), respectively, of locusta migratoria have been isolated and sequenced. the three l. migratoria akh precursors have an overall architecture similar to that of other precursors of the akh/red pigment-concentrating hormone (rpch) family identified so far. the akh i and ii precursors of l. migratoria are highly homologous to the schistocerca gregaria and schistocerca nitans akh precursors. althou ... | 1995 | 7559443 |
| a highly conserved red pigment-concentrating hormone precursor in the blue crab callinectes sapidus. | a cdna library was established from the eyestalk ganglia of the blue crab callinectes sapidus. one clone was isolated (644 bp excluding the poly(a) tail) which encodes the red pigment-concentrating hormone (rpch)-precursor, consisting of the 25 amino acid residue signal peptide, the rpch, and a 73 amino acid residue rpch-precursor related peptide. this clone displays high sequence similarity with a clone isolated from an eyestalk cdna library of the shore crab carcinus maenas, in accordance with ... | 1995 | 7611999 |
| modulation of membrane fluidity and lipidic metabolism in transformed rat fibroblasts induced by the sesquiterpenic hormone farnesylacetone. | farnesylacetone is a natural terpene extracted from androgenic glands of the crustacean carcinus maenas and is capable of inhibiting proliferation, notably in transformed mammalian cells. flow cytometry with three lipophilic probes, diphenylhexatriene, trimethylammonium-diphenylhexatriene, and nile red, has revealed modifications of the lipidic metabolism in transformed fr3t3-mtt4 rat fibroblasts treated by farnesylacetone, including changes in membrane fluidity. farnesylacetone strongly increas ... | 1995 | 7736867 |
| comparison of antibacterial activity in the hemocytes of different crustacean species. | antibacterial activity in hemocytes of the squat lobster, galathea strigosa, the norway lobster, nephrops norvegicus, the common shrimp, crangon crangon, and the giant antarctic isopod, glyptonotus antarcticus, was investigated in vitro. for all species, the marine bacterium, psychrobacter immobilis, was used as the test organism, although with g. antarcticus, the gram positive bacteria, planococcus citreus and bs 68 (an isolate from antarctic waters), were also used. hemocyte lysate supernatant ... | 1995 | 7866773 |
| high-level secretion of hirudin by hansenula polymorpha--authentic processing of three different preprohirudins. | a dna sequence coding for a subtype of the hirudin variant hv1 was expressed in the methylotrophic yeast hansenula polymorpha from a strongly inducible promoter element derived from a gene of the methanol metabolism pathway. for secretion, the coding sequence was fused to the kex2 recognition site of three different prepro segments engineered from the mf alpha 1 gene of saccharomyces cerevisiae, the glucoamylase (gam1) gene of schwanniomyces occidentalis and the gene for a crustacean hyperglycem ... | 1995 | 8597538 |
| complete primary structure of the molt-inhibiting hormone (mih) of the mexican crayfish procambarus bouvieri (ortmann). | 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 ( ... | 1996 | 8735961 |
| amino acid sequence of a peptide with molt-inhibiting activity from the kuruma prawn penaeus japonicus. | six major peptides (pej-sgp-i-vi) that belong to the chh family have been isolated from the sinus gland extracts of the kuruma prawn penaeus japonicus. by in vitro assay using the y-organ of the crayfish procambarus clarkii, pej-sgp-iv was found to be active in inhibiting ecdysteroid synthesis. we determined the complete amino acid sequence. pej-sgp-iv consists of 77 amino acid residues, with both free aimno- and carboxyl-termini. the sequence of pej-sgp-iv shows considerable similarity to that ... | 1996 | 8801521 |
| purification and characterization of a proline-rich antibacterial peptide, with sequence similarity to bactenecin-7, from the haemocytes of the shore crab, carcinus maenas. | antibacterial peptides are important for non-specific host defence in many animals. they have been extensively characterized from mammals, amphibians, insects and chelicerates but have not so far been found in crustaceans. here we report the presence of several constitutive antibacterial proteins, active against both gram-positive and gram-negative bacteria, in the haemocytes of the shore crab, carcinus maenas. these proteins have molecular masses of > 70 kda, approximately 45 kda, approximately ... | 1996 | 8856051 |
| evidence for the involvement of 3-oxo-delta 4 intermediates in ecdysteroid biosynthesis. | although the involvement of 3-oxo-delta 4 compounds as intermediates in arthropod ecdysteroid biosynthesis has been postulated for a long time, it has not yet been directly demonstrated. in the present study, 3-oxo-delta 4-steroids have been synthesized and incubated in vitro with dissociated moulting gland cells from the crab carcinus maenas. the tritiated compounds were converted into 3-dehydroecdysone, ecdysone and/or 25-deoxyecdysone, i.e. final ecdysteroids. this means that the 3-oxo-delta ... | 1996 | 8973547 |
| endocrine regulation of the phosphatidylinositol pathway in the norway lobster, nephrops norvegicus, and the shore crab, carcinus maenas. | the present study examines the mode of action of eyestalk factors, in particular crustacean hyperglycaemic hormone (chh), on known target tissues (muscle and hepatopancreas) in two decapod crustacean species, nephrops norvegicus and carcinus maenas. the possibility that receptors to chh are coupled to an elevation of cytosolic ca2+ derived from intracellular stores via activation of the phosphatidylinositol pathway was investigated. using an inositol 1,4,5-trisphosphate (insp3)-specific competit ... | 1996 | 8921359 |
| neuropeptide-induced inhibition of steroidogenesis in crab molting glands: involvement of cgmp-dependent protein kinase. | in crustaceans, ecdysteroid production by the molting glands (y-organs) is negatively regulated by a neuropeptide, molt-inhibiting hormone (mih). the involvement of cyclic nucleotide-dependent kinases in the mechanism of action of this neuropeptide was investigated with regard to the steroidogenic activity of carcinus maenas y-organs. regardless of the activity level, the major phosphotransferase activity measured in cytosolic fraction was cgmp-dependent, indicating a relatively high cytosolic c ... | 1996 | 8921354 |
| purification, kinetical and molecular characterizations of a serine collagenolytic protease from greenshore crag (carcinus maenas) digestive gland. | a serine collagenolytic protease was purified from a water soluble fraction of greenshore crab digestive gland by acidic precipitation, gel filtration on a sephadex g-50 column, ion-exchange chromatography on a fractogel tsk deae column, immobilized metal ion affinity chromatography (imac) on ida (cu2+) sepharose 6b and ion-exchange chromatography on hyper d column. the molecular mass of the monomeric carcinus serine collagenase (csc) was estimated to be 23,000 by sds page and its isoelectric po ... | 1996 | 8896334 |
| does the n-terminal pyroglutamate residue have any physiological significance for crab hyperglycemic neuropeptides? | a characteristic feature of all crustacean hyperglycemic hormones (chh) is that they are always present in the sinus gland as multiple forms or isoforms. the amino acid sequence of the minor form of chh from the green shore crab, carcinus maenas, was determined by automated microsequencing and ms, and was almost identical to that of the major form, except that the n-terminal residue was glutamine rather than pyroglutamate. limited analysis (electrospray ms and amino acid composition) of the two ... | 1996 | 8841399 |
| crab clockwork: the case for interactive circatidal and circadian oscillators controlling rhythmic locomotor activity of carcinus maenas. | the circalunidian hypothesis that tidal rhythms in coastal animals are controlled by two lunar-day (c.24.8 h) oscillators coupled in antiphase is challenged. rhythmic locomotor activity patterns of the shore crab carcinus maenas, and probably of some other species too, are more economically explained by interacting circadian (c.24 h) and true circatidal (c.12.4 h) physiological oscillators. a testable hypothesis is proposed that combines a circadian promotor and a circatidal inhibitor of locomot ... | 1996 | 8874979 |
| sensory feedback and central afferent interaction in the muscle receptor organ of the crab, carcinus maenas. | 1. an interaction exists between two proprioceptive afferent neurons innervating the thoracic-coxal muscle receptor organ (tcmro) of the crab, carcinus maenas. intracellular recordings were made from the extraganglionic regions of the afferents in order to characterize this interaction and its effects on sensory feedback. 2. a current-induced depolarization of the nonspiking t fiber of the tcmro results in a depolarization of the p fiber, a small-diameter (7 microns) neuron innervating the same ... | 1996 | 8871199 |
| sensory characteristics of the p afferent neurone of the crab thoracic-coxal muscle receptor organ. | intracellular recordings were made from the p fibre, the smallest of the three afferent neurones innervating the thoracic-coxal muscle receptor organ of the crab (carcinus maenas). while the two larger afferents are nonspiking, the response of the p fibre to a trapezoidal change in receptor muscle length consists of a single action potential signalling the onset of stretch superimposed on a graded amplitude receptor potential. the p fibre is sensitive to the velocity of the applied stretch, but ... | 1996 | 8765562 |
| infestation of an introduced host, the european green crab, carcinus maenas, by a symbiotic nemertean egg predator, carcinonemertes epialti. | the recent introduction of the european green crab, carcinus maenas, to the west coast of the u.s. has provided an opportunity for host transfer of the symbiotic nemertean egg predator, carcinonemertes epialti, from its native shore crab host, hemigrapsus oregonensis to the exotic c. maenas. two surveys of c. maenas in bodega harbor, california, revealed that, in march 1995 prevalence of c. epialti on c. maenas was significantly lower than on h. oregonensis (11% versus 74%), but in november 1995 ... | 1996 | 8636851 |
| the o-diphenol oxidase activity of arthropod hemocyanin. | arthropod hemocyanin (isolated from the crab carcinus maenas and the lobster homarus americanus) is usually referred to as an oxygen transport-storage protein. the protein, however, also catalyses with low efficiency the oxidation of o-diphenol to quinone, similarly to tyrosinase (monophenol, o-diphenol:oxygen oxidoreductase). the enzymatic parameters of hemocyanin are affected by the aggregation state of the protein; namely v(max) exhibited by a dissociated subunit is one order of magnitude gre ... | 1996 | 8617365 |
| nitrite reductase activity of deoxy carcinus maenas hemocyanin: formation of the half-met derivative. | 1996 | 11666340 | |
| apparent water permeability as a physiological parameter in crustaceans | this article reviews the use of apparent water permeability (awp) calculated from measurements of isotope-labelled water flux as a physiological estimate of whole-body water permeability in aquatic invertebrates. the rationale and practices of awp calculations are described in an appendix. awp calculations have provided a wealth of information. however, the validity of the method and therefore also of the information obtained have been questioned. consequently, the use of awp data in discussions ... | 1996 | 9320480 |
| active absorption of na+ and cl- across the gill epithelium of the shore crab carcinus maenas: voltage-clamp and ion-flux studies | mechanisms of active nacl uptake across the posterior gills of the shore crab carcinus maenas were examined using radiochemical and electrophysiological techniques. in order to measure short-circuit current (isc), transepithelial conductance (gte) and area-related unidirectional fluxes of na+ and cl-, single split gill lamellae (epithelium plus cuticle) of hyperregulating shore crabs were mounted in a modified ussing chamber. the negative short-circuit current measured with haemolymph-like nacl ... | 1996 | 9319445 |
| opioid receptor types for endogenous enkephalin in the thoracic ganglion of the crab, carcinus maenas. | in crustaceans, the endogenous opioid peptides, enkephalins, are known to be concentrated in the thoracic ganglion, although they have been demonstrated in all parts of the nervous system. bmax and kd measurements have been obtained for the binding of ligands used to characterize delta- and kappa-type opioid receptors in vertebrates. high- and low affinity binding of [3h] [2-d-pen5-d pen] enkephalin ([3h]dpdpe) has been measured with a kd = 9.2 +/- 2.4 nm, bmax = 153 fmol/mg, and kd = 243 +/- 27 ... | 1996 | 8899815 |
| isolation and identification of multiple neuropeptides of the allatostatin superfamily in the shore crab carcinus maenas. | 20 neuropeptides belonging to the allatostatin superfamily were isolated from extracts of cerebral and thoracic ganglia of the shore crab carcinus maenas. they were purified by hplc, monitored by radioimmunoassay and identified by mass spectrometry and amino acid sequencing. the allatostatins are characterised by a common c-terminal pentapeptide sequence -yxfgl-nh2. previously such peptides have only been reported from insects. in insects the variable post-tyrosyl residue is restricted to ala, a ... | 1997 | 9461295 |
| "exolysosomes," enzyme-containing vesicles in the ecdysial space of molting crabs. | free vesicle-like bodies (vlbs) present in the ecdysial space of cuticle regions undergoing degradation during preecdysis of the atlantic shore crab carcinus maenas have been interpreted either as infectious organisms or as secretion structures associated with degradation of the old cuticle. ultrastructural, cytochemical, and immunocytological investigations were performed to test these hypotheses and to see whether vlbs are peculiar to this crab species. similar vlbs were systematically found i ... | 1997 | 9245765 |