| lactate dehydrogenase from the abdomen and heart muscle of the crayfish orconectes limosus. | | 1982 | 6217947 |
| ecdysteroid receptors: a comparison of cytoplasmic and nuclear receptors from crayfish hypodermis. | cytoplasmic and nuclear ecdysteroid receptors from intermolt orconectes limosus integument have been compared. the specificities as well as the kd values for three [3h]ecdysteroids are very similar in both preparations. using a photoaffinity labelling technique, the molecular mass of the hormone-receptor complexes from both preparations was determined by sodium dodecyl sulfate-gel electrophoresis as 70 000 da. the isoelectric points are about 6 in both cases. nuclear receptor can be extracted by ... | 1982 | 7118075 |
| unusual behaviour of nadp-linked malic enzyme from crustacean tissues on 2',5' adp-sepharose 4b. | 1. essential differences in the binding of nadp-dependent malic enzymes from mammals, fish and crustacea to 2',5' adp-sepharose 4b have been shown. 2. the enzymes from mammalian and fish tissues interact with 2',5' adp-sepharose, whereas the enzymes from crayfish orconectes limosus and shrimp crangon crangon tissues do not. 3. these results provide evidence that 2',5' adp-sepharose cannot be used for the purification of nadp-dependent malic enzyme from crayfish and shrimp and indicate presumably ... | 1982 | 7128115 |
| a novel ef-hand ca(2+)-binding protein from abdominal muscle of crustaceans with similarity to calcyphosine from dog thyroidea. | the amino acid sequence of a novel ef-hand ca(2+)-binding protein from the abdominal muscle of the crayfish, orconectes limosus, has been elucidated by tandem mass spectrometry and automated edman degradation. the name ccbp-23 (23-kda crustacean ca(2+)-binding protein) is proposed. the protein can also exist as a disulfide-linked homodimer. the sequence of the monomeric form spans 200 residues with an acetylated n-terminal ser and reveals four ef-hand domains. the 174-mass-unit difference betwee ... | 1995 | 7851448 |
| demonstration of a cell-specific isomerization of invertebrate neuropeptides. | neurohemal organs of the lobster homarus americanus contain isoforms of the crustacean hyperglycemic hormone, which differ by the third amino acid (phenylalanyl) residue that is either in the l- or in the d-configuration. polyclonal antisera have been raised in rabbit against synthetic octapeptides with the sequence corresponding to the n-terminal part of the l- or d-phenylalanine-containing isoforms. their specificity was shown by immunoassays, indicating that they discriminate the isoforms of ... | 1998 | 9483547 |
| cloning and characterization of the l15 ribosomal protein gene homologue from the crayfish orconectes limosus. | a cdna homologue of the large unit rat ribosomal protein l15 was cloned from an epidermal cdna library of the crayfish orconectes limosus, being the first crustacean ribosomal protein gene cloned to date. it contains 204 amino acids, deduced from the nucleotide sequence, and reveals 70-76% sequence identity with other arthropod and vertebrate ribosomal l15s. a single, abundant 0.7-kb mrna transcript was constitutively expressed and revealed similar expression levels, among various adult crayfish ... | 1999 | 10080916 |
| a permanent cell line of the crayfish orconectes limosus as a potential model in comparative oncology. | a cell line, designated olga-ph-j/92, was established from neuronal tissue of the crayfish orconectes limosus. to date the cell line has been subcultured more than 150 times. from the original cell line two 'daughter' cell lines and one cloned cell line were isolated. best growth was obtained when the cells were incubated in eagle's minimum essential medium supplemented with 6% fetal bovine serum at a temperature of 27 degrees c. under these conditions the population doubling time lasted between ... | 2000 | 11125551 |
| laboratory and field assessment of uranium trophic transfer efficiency in the crayfish orconectes limosus fed the bivalve c. fluminea. | at present, ecotoxicological information regarding the impact of natural uranium (u) on freshwater ecosystems via the trophic contamination route is scarce. we generated an experimental trophic food chain involving the prey species, corbicula fluminea, and a predator, orconectes limosus, for a 10-day and a 30-day feeding periods (food ration: one whole soft body/day/crayfish). we studied the efficiency of u trophic transfer and the distribution of u in the predator. during the test, we varied th ... | 2005 | 16087252 |
| antioxidant defence enzyme activities in hepatopancreas, gills and muscle of spiny cheek crayfish (orconectes limosus) from the river danube. | the aim of our study was to determine the activity of antioxidant defence (ad) enzymes: superoxide dismutase (sod), catalase (cat), glutathione peroxidase (gsh-px), glutathione reductase (gr) and the phase ii biotransformation enzyme glutathione-s-transferase (gst) in the hepatopancreas, the gills and muscle of spiny cheek crayfish (orconectes limosus) from the river danube and to compare tissue specificities of investigated enzymes. our results indicated that both specific and total sod activit ... | 2008 | 17889622 |
| infection with acanthocephalans increases the vulnerability of gammarus pulex (crustacea, amphipoda) to non-host invertebrate predators. | phenotypic alterations induced by parasites in their intermediate hosts often result in enhanced trophic transmission to appropriate final hosts. however, such alterations may also increase the vulnerability of intermediate hosts to predation by non-host species. we studied the influence of both infection with 3 different acanthocephalan parasites (pomphorhynchus laevis, p. tereticollis, and polymorphus minutus) and the availability of refuges on the susceptibility of the amphipod gammarus pulex ... | 2008 | 18371238 |
| prevalence of the crayfish plague pathogen aphanomyces astaci in invasive american crayfishes in the czech republic. | in central europe invasive north american crayfishes are carriers of the oomycete aphanomyces astaci, which causes crayfish plague. this lethal disease currently represents one of the major threats to native european crayfishes. we used molecular methods-species--specific amplification and sequencing of the pathogen dna--to investigate the prevalence of individuals latently infected with a. astaci in 28 populations of two invasive american crayfish species (6 of the signal crayfish [pacifastacus ... | 2009 | 19459897 |
| spiny-cheek crayfish orconectes limosus carry a novel genotype of the crayfish plague pathogen aphanomyces astaci. | the oomycete aphanomyces astaci causes mass mortalities of european crayfish. different species of north american crayfish, original hosts of this parasite, seem to carry different strains of a. astaci. so far, four distinct genotype groups have been recognised using random amplification of polymorphic dna (rapd-pcr). we succeeded in isolating a. astaci from the spiny-cheek crayfish orconectes limosus, a widespread invader in europe, and confirmed that this species carries a novel a. astaci geno ... | 2011 | 21856310 |
| re-examination of the prevalence of aphanomyces astaci in north american crayfish populations in central europe by taqman mgb real-time pcr. | we applied quantitative taqman minor groove binder real-time polymerase chain reaction (pcr) on dna isolates from soft abdominal cuticle of 460 north american crayfish orconectes limosus and pacifastacus leniusculus, previously tested for aphanomyces astaci presence by conventional semi-nested pcr. both approaches target the internal transcribed spacers of the pathogen nuclear ribosomal dna, but apply different specific sequence motifs and technologies. the real-time pcr approach seems to provid ... | 2011 | 22303628 |
| amino acid sequence of crustacean hyperglycemic hormone (chh) from the crayfish, orconectes limosus: emergence of a novel neuropeptide family. | the primary structure of the major form of chh from sinus glands of the crayfish, orconectes limosus, was determined by manual edman microsequencing. it is a 72-residue peptide with a calculated mr of 8400 da. in the number of residues, it is identical to the chh of carcinus maenas and very similar to mih (moult inhibiting hormone) of homarus americanus. all three peptides have pglu as n-terminus in common, and val-nh2 is the c-terminal residue in orconectes and carcinus chh. six cys residues oc ... | 2007 | 1800954 |
| potentiation of a transient outward current by na+ influx in crayfish neurones. | in voltage-clamped "motor-giant" neurones of the crayfish orconectes limosus a depolarizing voltage step elicits a transient inward current carried by na+ which is followed by an early and a delayed outward current. the early outward current is reduced if the na+ current is suppressed by tetrodotoxin or the removal of external na+. it is also abolished if the k+ channel blocking agents tetraethylammonium and 3,4-diaminopyridine are applied to the neurone. the outward current was not depressed if ... | 2004 | 2409521 |
| ecdysteroid production by the cephalic gland of the crayfish orconectes limosus. | | 2004 | 520813 |
| interneurons in the tritocerebrum of the crayfish. | in isolated head preparations of the freshwater crayfish orconectes limosus 268 local and projecting interneurons with branches in the tritocerebrum have been penetrated with glass microelectrodes and characterized for their sensory inputs. using 3 criteria (sensory modality, site of receptors, response type of interneurons), the interneurons found were divided into 16 classes. the interneurons were either unimodal mechanoreceptive (89%) or bimodal (9% responding to mechanical and chemical stimu ... | 2012 | 3567643 |
| [specific toxic properties of metal salts of austro-potamobius pallipes pallipes and orconectes limosus]. | | 2016 | 4802734 |
| isolation and some properties of mitochondria from the abdomen muscle of the crayfish orconectes limosus. | | 2003 | 187373 |
| the significance of droughts for hyporheic dwellers: evidence from freshwater crayfish. | freshwater biodiversity is globally threatened by various factors while severe weather events like long-term droughts may be substantially devastating. in order to remain in contact with the water or stay in a sufficiently humid environment at drying localities, the ability to withstand desiccation by dwelling in the hyporheic zone, particularly through vertical burrowing is crucial. we assessed the ability of three european native and five non-native crayfish as models to survive and construct ... | 2016 | 27225308 |
| effect of experimental exposure to differently virulent aphanomyces astaci strains on the immune response of the noble crayfish astacus astacus. | european crayfish are sensitive to the crayfish plague pathogen, aphanomyces astaci, carried by north american crayfish species due to their less effective immune defence mechanisms against this disease. during a controlled infection experiment with a susceptible crayfish species astacus astacus using three a. astaci strains (representing genotype groups a, b, and e), we investigated variation in their virulence and in crayfish immune defence indicators (haemocyte density, phenoloxidase activity ... | 2015 | 26410255 |
| temporal dynamics of spore release of the crayfish plague pathogen from its natural host, american spiny-cheek crayfish (orconectes limosus), evaluated by transmission experiments. | the crayfish plague pathogen, aphanomyces astaci, is one of the most serious threats to indigenous european crayfish species. the north american invasive spiny-cheek crayfish, orconectes limosus, is an important source of this pathogen in central and western europe. we evaluated potential changes in a. astaci spore release rate from infected individuals of this species by experiments investigating the pathogen transmission to susceptible noble crayfish, astacus astacus. we filtered defined volum ... | 2013 | 23425502 |
| the concentrations of antioxidant compounds in the hepatopancreas, the gills and muscle of some freshwater crayfish species. | we examined the concentrations of vitamin e (vit e), sulphydryl groups (-sh), total protein and protein electrophoretic profiles in the hepatopancreas, the gills and muscle of three freshwater crayfish species: noble crayfish (astacus astacus), stone crayfish (austropotamobius torrentium) and spiny cheek crayfish (orconectes limosus). vit e concentration in the hepatopancreas of o. limosus was lower compared to a. astacus, while in the gills of o. limosus it was lower compared to both a. astacus ... | 2006 | 17278707 |
| crustacean cardioactive peptide-immunoreactive neurons in the ventral nervous system of crayfish. | crustacean cardioactive peptide-immunoreactive neurons have been mapped in whole-mount preparations and sections of the ventral nervous system of the crayfish astacus astacus and orconectes limosus. based on their morphology, projection patterns, and staining characteristics, two types of contralaterally projecting neurons are individually identifiable. in both species, these neurons occur in all neuromers as apparent serial homologs. in adult specimens, one type of cell has a small, densely sta ... | 1994 | 7814685 |
| quantitative determination and distribution of the myotropic neuropeptide orcokinin in the nervous system of astacidean crustaceans. | for quantitative determinations of orcokinin, an indirect, noncompetitive sandwich elisa was developed. this elisa is highly specific for orcokinin and the detection limit is 1 fmol. in three astacidean species (orconectes limosus, homarus americanus, and astacus astacus) orcokinin immunoreactivity (ok-ir) was measurable in all parts of the nervous system. upon normalization to the protein content of the tissue (pmol/mg protein), concentrations were shown to be in the same range in all three spe ... | 1994 | 7937311 |
| a new endocrine gland in the antennal segment of the crayfishes orconectes limosus and astacus astacus. | | 1979 | 520811 |
| plasticity in fecundity highlights the females' importance in the spiny-cheek crayfish invasion mechanism. | invasion is one of the most consequential phenomena affecting the distribution of native species. few in number of species, european crayfish are losing the competition with introduced north american crayfish. the spiny-cheek crayfish, orconectes limosus, is an outstanding example, successfully competing against the native narrow-clawed crayfish, astacus leptodactylus. for four years, we collected data regarding crayfish occurrences, their relative abundance, and the structure of populations in ... | 2015 | 26358988 |
| invasive crayfish and crayfish plague on the move: first detection of the plague agent aphanomyces astaci in the romanian danube. | native european crayfish, such as astacus leptodactylus, are threatened, among other factors, by the crayfish plague agent aphanomyces astaci, dispersed by invasive north american crayfish. two of these invaders, pacifastacus leniusculus and orconectes limosus, have extended their distribution in the river danube catchment; the latter was detected for the first time in romania in 2008. we monitored, at monthly intervals for over 2 yr, occurrence of native a. leptodactylus and invasive o. limosus ... | 2012 | 22422132 |
| posttranslational isomerization of a neuropeptide in crustacean neurosecretory cells studied by ultrastructural immunocytochemistry. | isomerization of the third amino acid residue (a phenylalanine) of crustacean hyperglycemic hormone (chh) has been previously reported to occur as a late step of hormone precursor maturation in a few neurosecretory cells in the x-organ-sinus gland complex of the crayfish orconectes limosus. in the present report, using conformation-specific antisera combined with immunogold labeling, we have studied, at the ultrastructural level, the distribution of l- and d-chh immunoreactivity in chh-secreting ... | 2003 | 14533741 |
| distribution of centrifugal neurons targeting the soma clusters of the olfactory midbrain among decapod crustaceans. | to determine the distribution of two systems of centrifugal neurons innervating the soma clusters of the olfactory midbrain across decapod crustaceans, brains of the following nine species comprising most infraorders were immunostained with antibodies against dopamine and the neuropeptides substance p and fmrfamide: macrobrachium rosenbergii, homarus americanus, cherax destructor, orconectes limosus, procambarus clarkii, astacus leptodactylus, carcinus maenas, eriocheir sinensis and pagurus bern ... | 1997 | 9106436 |
| phosphorus fractions of crayfish haemolymph, serum and haemocyanin. | different amounts of haemolymph proteins participate in clot formation in astacus leptodactylus and orconectes limosus (20% and 10%, respectively), although in both species the content of proteins in haemolymph is similar. in both species the content of total phosphorus in the clot was similar (0.33-0.49%, w/w) but it was about 6 times lower in serum of o. limosus than in serum of a. leptodactylus (2.2 and 14.8 mg/100 ml, respectively). an even greater difference in phosphorus content was found ... | 1985 | 4090857 |
| [comparative analysis of cu2+ toxicity in astacus leptodactylus and orconectes limosus: depression of ion-regulatory functions and of na-k dependant atpase activity in the gills]. | | 1973 | 4278905 |
| prevalence of the crayfish plague pathogen aphanomyces astaci in populations of the signal crayfish pacifastacus leniusculus in france: evaluating the threat to native crayfish. | aphanomyces astaci, the crayfish plague pathogen, first appeared in europe in the mid-19(th) century and is still responsible for mass mortalities of native european crayfish. the spread of this parasite across the continent is especially facilitated by invasive north american crayfish species that serve as its reservoir. in france, multiple cases of native crayfish mortalities have been suggested to be connected with the presence of the signal crayfish pacifastacus leniusculus, which is highly ... | 2013 | 23894606 |
| identification of orcokinin gene-related peptides in the brain of the crayfish procambarus clarkii by the combination of maldi-tof and on-line capillary hplc/q-tof mass spectrometries and molecular cloning. | we developed a strategy for the exploration of brain peptides in the red swamp crayfish, procambarus clarkii, utilizing the combined techniques of matrix-assisted laser desorption/ionization with time-of-flight mass spectrometry (maldi-tof ms), molecular cloning, and on-line capillary reversed-phase hplc/quadrupole orthogonal acceleration time-of-flight (q-tof)-ms. we initially performed direct maldi-tof ms analysis with slices of the brain. the ms spectra from a slice of the olfactory lobe indi ... | 2000 | 10753578 |
| ecdysis of decapod crustaceans is associated with a dramatic release of crustacean cardioactive peptide into the haemolymph. | on the basis of detailed analyses of morphological characteristics and behavioural events associated with ecdysis in a crab (carcinus maenas) and a crayfish (orconectes limosus), a comprehensive substaging system has been introduced for the ecdysis stage of the moult cycle of these decapod crustaceans. in a remarkably similar stereotyped ecdysis sequence in both species, a passive phase of water uptake starting with bulging and rupture of thoracoabdominal exoskeletal junctions is followed by an ... | 2000 | 10637181 |
| structure, distribution, and biological activity of novel members of the allatostatin family in the crayfish orconectes limosus. | in the central and peripheral nervous system of the crayfish, orconectes limosus, neuropeptides immunoreactive to an antiserum against allatostatin i (= dipstatin 7) of the cockroach diploptera punctata have been detected by immunocytochemistry and a sensitive enzyme immunoassay. abundant immunoreactivity occurs throughout the central nervous system in distinct interneurons and neurosecretory cells. the latter have terminals in well-known neurohemal organs, such as the sinus gland, the pericardi ... | 1999 | 10477125 |
| evidence for the involvement of the crustacean hyperglycemic hormone in the regulation of lipid metabolism. | effects of the crustacean hyperglycemic hormone on total lipids in the hemolymph of chasmagnathus granulata and on free fatty acids, phospholipids, and triglycerides in the hemolymph of carcinus maenas, as well as on their release by orconectes limosus hepatopancreas in vitro, were investigated. eyestalk ablation led to a significant decrease of total lipids in the hemolymph of c. granulata and of free fatty acid levels in c. maenas. crustacean hyperglycemic hormone injections completely reverse ... | 2011 | 9237301 |
| crustacean hyperglycaemic hormone in the nervous system of the primitive crustacean species daphnia magna and artemia salina (crustacea: branchiopoda). | crustacean hyperglycaemic hormone-immunoreactive neuronal systems are detected in the central and peripheral nervous systems of two entomostracan crustaceans, daphnia magna and artemia salina, by immunocytochemistry using specific antisera against crustacean hyperglycaemic hormones of the decapod crustaceans orconectes limosus and carcinus maenas. in d. magna, four small putative interneurones are detected in the brain. in the thorax, ten bipolar peripheral neurones are stained by both antisera. ... | 1997 | 9023085 |
| 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 |
| 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 |
| primary structure of the major isomorph of the crustacean hyperglycemic hormone (chh-i) from the sinus gland of the mexican crayfish procambarus bouvieri (ortmann): interspecies comparison. | the amino acid sequence of this neuropeptide was elucidated by means of a combined approach of enzymatic digestions, manual and automatic edman degradations, and mass spectrometry. it is a 72 residue peptide (molecular mass 8388 da), with six cysteines forming three disulfide bridges connecting residues 7-43, 23-39, and 26-52, with blocked n- and c-termini, and lacking the amino acids histidine, methionine, and tryptophan. the chh-i of procambarus bouvieri is compared with the other known chhs f ... | 2011 | 8441709 |
| high-affinity binding of crustacean hyperglycemic hormone (chh) to hepatopancreatic plasma membranes of the crab carcinus maenas and the crayfish orconectes limosus. | the binding properties of the crustacean hyperglycemic hormone (chh) of two species, the shore crab, carcinus maenas (brachyura) and the crayfish, orconectes limosus (astacura), were investigated using purified plasma membranes of one of the main target organs, the hepatopancreas. assays were performed under equilibrium binding conditions with 125i-chh as labeled ligand and unlabeled chh in increasing concentrations as displacing ligand. in both cases, comparable binding characteristics were obs ... | 2011 | 8382808 |
| 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 |
| isolation and amino acid sequence of crustacean hyperglycemic hormone precursor-related peptides. | the crustacean hyperglycemic hormone (chh) is synthesized as part of a larger preprohormone in which the sequence of chh is n-terminally flanked by a peptide for which the name cprp (chh precursor-related peptide) is proposed. both chh and cprp are present in the sinus gland, the neurohemal organ of neurosecretory cells located in the eyestalk of decapod crustaceans. this paper describes the isolation and sequence analysis of cprps isolated from sinus glands of the crab carcinus maenas, the cray ... | 2011 | 1788131 |
| 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 |
| identification of orcokinins in single neurons in the stomatogastric nervous system of the crayfish, cherax destructor. | the orcokinins are a highly conserved family of crustacean peptides that enhance hindgut contractions in the crayfish orconectes limosus (stangier et al. [1992] peptides 13:859-864). by combining immunocytochemical and mass spectrometrical analysis of the stomatogastric nervous system (stns) in the crayfish cherax destructor, we show that multiple orcokinins are synthesized in single neurons. immunocytochemistry demonstrated orcokinin-like immunoreactivity in all four ganglia of the stns and in ... | 2002 | 11840478 |
| circulation of copper in the biotic compartments of a freshwater dammed reservoir. | this study concerns a chronic copper release in an aquatic ecosystem: mirgenbach reservoir; which is characterized by high salinity, conductivity and hardness, a eutrophic state and a high temperature. to study the bioavailability of copper in the biotic compartments, the sampling covered the entire food chain (phyto- and zooplankton, macroalgae, aquatic plants, crustaceans, mollusks, and fish). of the organisms present, the filter feeder dreissena polymorpha, the detritivorous bithynia tentacul ... | 2005 | 15327867 |
| a new cytochrome p450 from drosophila melanogaster, cyp4g15, expressed in the nervous system. | a novel cytochrome p450 was isolated from drosophila melanogaster by pcr strategy with primers deduced from the crayfish orconectes limosus cyp4c15 sequence, which is supposed to be involved in ecdysteroid biosynthesis. the full-length cdna contains a 1980 bp open reading frame encoding a predicted protein of 574 amino acids and was designated cyp4g15. the corresponding gene is located at 10c1 on the x chromosome. the presence of a n-terminal segment mainly hydrophobic indicated that the corresp ... | 2000 | 10891384 |
| survey of the crayfish plague pathogen presence in the netherlands reveals a new aphanomyces astaci carrier. | north american crayfish species as hosts for the crayfish plague pathogen aphanomyces astaci contribute to the decline of native european crayfish populations. at least six american crayfish species have been reported in the netherlands but the presence of this pathogenic oomycete with substantial conservational impact has not yet been confirmed in the country. we evaluated a. astaci prevalence in dutch populations of six alien crustaceans using species-specific quantitative pcr. these included ... | 2014 | 24933021 |
| the complete mitogenome of the invasive spiny-cheek crayfish orconectes limosus (rafinesque, 1817) (crustacea: decapoda: cambaridae). | the invasive freshwater crayfish orconectes limosus mitogenome was recovered by genome skimming. the mitogenome is 16,223 base pairs in length consisting of 13 protein-coding genes, 2 ribosomal subunit genes, 22 transfer rnas, and a non-coding at-rich region. the o. limosus mitogenome has an at bias of 71.37% and base composition of 39.8% for t, 10.3% for c, 31.5% for a, and 18.4% for g. the mitogene order is identical to two other genera of northern hemisphere crayfish that have been sequenced ... | 2016 | 25648916 |
| the thermal tolerance of crayfish could be estimated from respiratory electron transport system activity. | whether electron transport system (ets) activity could be used as an estimator of crayfish thermal tolerance has been investigated experimentally. food consumption rate, respiration rates in the air and water, the difference between energy consumption and respiration costs at a given temperature ('potential growth scope', pgs), and ets activity of orconectes limosus and pacifastacus leniusculus were determined over a temperature range of 5-30°c. all concerned parameters were found to be temperat ... | 2014 | 24679968 |
| reproductive plasticity in freshwater invader: from long-term sperm storage to parthenogenesis. | orconectes limosus, a north american crayfish species, is one of the most important aquatic invaders in european inland waters. despite more than 120 years occurrence in europe and intense research, there are still gaps in knowledge of its life history and ecology. investigation into o. limosus invasive success requires identifying the mechanisms that enabled them to establish dense and widespread populations from small initial numbers without observable limitation by an introduction bottleneck. ... | 2013 | 24204886 |
| markers of oxidative stress in hepatopancreas of crayfish (orconectes limosus, raf) experimentally exposed to nanosilver. | silver nanoparticles, chemically neutral particles in the size range of 1-100 nm, express strong antimicrobial activity and therefore have a broad range of applications. the increased use of consumer products with nanosilver (nanoag) may result in its release into the environment, and may particularly affect aquatic systems. the mechanisms of the harmful effects of nanoag against aquatic organisms are unclear. therefore, in the present study we investigate the pro-oxidative potential of these na ... | 2014 | 23460582 |
| relative importance of direct and trophic uranium exposures in the crayfish orconectes limosus: implication for predicting uranium bioaccumulation and its associated toxicity. | pollutants that occur at sublethal concentrations in the environment may lead to chronic exposure in aquatic organisms. if these pollutants bioaccumulate, then organisms higher in the food chain may also be at risk. increased attention has thus been focused on the relative importance of dietary uptake, but additional knowledge of the cellular distribution of metals after dietary exposure is required to assess the potential toxicity. the authors address concerns relating to increasing uranium (u) ... | 2013 | 23280947 |
| behavioural determinants of agonistic success in invasive crayfish. | ecosystems today increasingly suffer invasions by multiple invasive species, some of which may share similar advantageous life history traits and ecological niche. in such cases, direct competition can influence invasion success of both species, and provide insights into competition without co-evolution in species equally novel to the environment. we used two widespread crayfish invaders of freshwater ecosystems of europe, signal crayfish (pacifastacus leniusculus) and spiny cheek crayfish (orco ... | 2012 | 22688078 |
| misidentification of olga-ph-j/92, believed to be the only crustacean cell line. | continuous cell lines from aquatic invertebrate species are few and the development of crustacean cell lines remains an elusive goal. although a crayfish cell line derived from neural ganglia of orconectes limosus was reported in 2000, this cell line olga-ph-j/92 failed to be authenticated as such. in this report, we describe our attempts to identify the taxonomic identity of the cell line through immunological and molecular techniques. immunohistochemical screening for the expression of a suite ... | 2011 | 21938590 |
| a successful crayfish invader is capable of facultative parthenogenesis: a novel reproductive mode in decapod crustaceans. | biological invasions are impacting biota worldwide, and explaining why some taxa tend to become invasive is of major scientific interest. north american crayfish species, particularly of the family cambaridae, are prominent invaders in freshwaters, defying the "tens rule" which states that only a minority of species introduced to new regions become established, and only a minority of those become invasive and pests. so far, success of cambarid invaders has largely been attributed to rapid matura ... | 2011 | 21655282 |
| intra-sex dimorphism in crayfish females. | a unique cycle of female form alternation has been revealed in an experimental population of orconectes limosus during a year-long observation. significant cyclic changes observed in chelae length, width, and robustness, as well as in abdomen width, demonstrated a form alternation similar to that in conspecific males. small females alternate between sexually active and sexually inactive forms with a short time interval between successive molts as well as different growth patterns of some body pa ... | 2010 | 20932733 |
| cross-species amplification of microsatellite markers in the invasive spiny-cheek crayfish (orconectes limosus): assessment and application. | the north american spiny-cheek crayfish, orconectes limosus (cambaridae), endangered in its native range, is a widespread invasive species in european waters and conservationally important carrier of crayfish plague. however, its population structure is poorly known, and no informative genetic markers for the species are available. we tested cross-species transfer of microsatellite loci to spiny-cheek crayfish from 5 other crayfish species. variability of 10 successfully amplifying loci derived ... | 2010 | 20145303 |
| molecular, mass spectral, and physiological analyses of orcokinins and orcokinin precursor-related peptides in the lobster homarus americanus and the crayfish procambarus clarkii. | recently, cdnas encoding prepro-orcokinins were cloned from the crayfish procambarus clarkii; these cdnas encode multiple copies of four orcokinin isoforms as well as several other peptides. using the translated open reading frames of the p. clarkii transcripts as queries, five ests encoding american lobster homarus americanus orthologs were identified via blast analysis. from these clones, three cdnas, each encoding one of two distinct prepro-hormones, were characterized. predicted processing o ... | 2009 | 19007832 |
| characterization of a molt-inhibiting hormone (mih) of the crayfish, orconectes limosus, by cdna cloning and mass spectrometric analysis. | the structure of the precursor of a molt-inhibiting hormone (mih) of the american crayfish, orconectes limosus was determined by cloning of a cdna based on rna from the neurosecretory perikarya of the x-organ in the eyestalk ganglia. the open reading frame includes the complete precursor sequence, consisting of a signal peptide of 29, and the mih sequence of 77 amino acids. in addition, the mature peptide was isolated by hplc from the neurohemal sinus gland and analyzed by esi-ms and maldi-tof-m ... | 2005 | 16269348 |
| identification of neuropeptides from the sinus gland of the crayfish orconectes limosus using nanoscale on-line liquid chromatography tandem mass spectrometry. | in this article, a novel and sensitive analytical strategy for direct characterization of neuropeptides from the x-organ-sinus gland neurosecretory system of the crayfish orconectes limosus is presented. a desalted extract corresponding to 0.5 sinus gland equivalents was analyzed in a nanoflow liquid chromatography system coupled to quadrupole time-of-flight tandem mass spectrometry (nanolc-qtof ms/ms). the existence and structural identity of four crustacean hyperglycemic hormone precursor-rela ... | 2004 | 14981133 |
| neuropeptidomic analysis of the brain and thoracic ganglion from the jonah crab, cancer borealis. | mass spectrometric methods were applied to determine the peptidome of the brain and thoracic ganglion of the jonah crab (cancer borealis). fractions obtained by high performance liquid chromatography were characterized using maldi-tof ms and esi-q-tof ms/ms. in total, 28 peptides were identified within the molecular mass range 750-3000da. comparison of the molecular masses obtained with maldi-tof ms with the calculated molecular masses of known crustacean peptides revealed the presence of at lea ... | 2003 | 12914784 |
| phenotype plasticity in postural muscles of the crayfish orconectes limosus raf.: correlation of myofibrillar atpase-based fiber typing with electrophysiological fiber properties and the effect of chronic nerve stimulation. | the characteristics of the medial and lateral superficial extensor muscles (sem and sel) in the crayfish orconectes limosus abdomen and their developmental and activity-dependent plasticity were studied. it was shown that both muscles are innervated by at least five excitatory and one inhibitory motor neuron in a nonuniform pattern. the muscles are composed of at least three different matpase histochemistry-based fiber types that are all different from a fourth type in the uniform deep extensor ... | 2002 | 12115909 |
| enkephalinergic control of the secretory activity of neurons producing stereoisomers of crustacean hyperglycemic hormone in the eyestalk of the crayfish orconectes limosus. | a subgroup of neurons in the classical x organ sinus gland neuroendocrine system of the crayfish (orconectes limosus) eyestalk produces two chiral forms of the crustacean hyperglycemic hormone (chh) in two different types of neurons: chh in 22 cells and d phe(3) chh in eight cells. previous reports have demonstrated that release of chh from the sinus gland is inhibited by enkephalins. here, we have addressed the questions of 1) whether this inhibition affects one or both types of chh neurons, 2) ... | 2002 | 11835178 |
| molting cycle-dependent expression of cyp4c15, a cytochrome p450 enzyme putatively involved in ecdysteroidogenesis in the crayfish, orconectes limosus. | a cytochrome p450 enzyme cdna (cyp4c15) has been previously cloned from a cdna library of crayfish steroidogenic glands (y-organs). the conceptual translation of the cyp4c15 cdna sequence was analyzed for regions of putative high antigenicity and a mixture of two synthetic peptides was chosen for the production of a specific polyclonal antibody. western blot analysis on y-organ subcellular fractions indicated an endoplasmic reticulum location of cyp4c15, in agreement with the structural feature ... | 2002 | 11755057 |
| molecular cloning of a novel crustacean member of the aldoketoreductase superfamily, differentially expressed in the antennal glands. | biochemical studies on ecdysteroid metabolism in arthropods suggest that aldoketoreductase enzymes (akrs) may be involved in this pathway, but very few molecular data are available on these oxidoreductases in invertebrates. looking for such enzymes in the crayfish orconectes limosus, we have used a pcr strategy with primers deduced from a recent insect 3beta-reductase sequence, and from mammalian 5beta-reductase sequences. a full-length cdna, corresponding to a putative akr, was isolated from cr ... | 2001 | 11264009 |
| effects of serotonin and fluoxetine on blood glucose regulation in two decapod species. | one of the best known crustacean hormones is the crustacean hyperglycemic hormone (chh). however, the mechanisms involved in hormone release in these animals are poorly understood, and thus constitute the central objective of the present study. different groups of crustaceans belonging to diverse taxa (chasmagnathus granulata, a grapsid crab and orconectes limosus, an astacid) were injected with serotonin, fluoxetine, or a mixture of both, and glycemic values (c. granulata and o. limosus) and ch ... | 2001 | 11151031 |
| two orcokinins and the novel octapeptide orcomyotropin in the hindgut of the crayfish orconectes limosus: identified myostimulatory neuropeptides originating together in neurones of the terminal abdominal ganglion. | the tridecapeptides asn(13)-orcokinin and val(13)-orcokinin, two known members of the orcokinin neuropeptide family native to crustaceans, and a novel octapeptide, orcomyotropin, fdafttgfamide, have been identified from extracts of hindguts of the crayfish orconectes limosus using an isolated hindgut contractility bioassay, high-performance liquid chromatography, microsequencing and mass spectrometry. all three peptides display strong inotropic actions on crayfish hindguts. orcomyotropin showed ... | 2000 | 10952880 |
| dynamics of biosynthesis and release of crustacean hyperglycemic hormone isoforms in the x-organ-sinus gland complex of the crayfish orconectes limosus. | the crustacean hyperglycemic hormone (chh) is the major neuropeptide produced by the x-organ-sinus gland neurosecretory system of the crayfish, orconectes limosus. this hormone is synthesized by two different cell types, as two isomers (chh and d-phe3-chh) which display different activities the aim of this report is to analyze and compare the synthetic and secretory activities of these specialized cells. in vitro pulse-chase incubations and time-course experiments were conducted on isolated x-or ... | 2000 | 10931194 |
| ecdysteroid biosynthesis in crayfish y-organs: feedback regulation by circulating ecdysteroids | in crustaceans, ecdysteroid synthesis in the y-organs is negatively regulated by the molt-inhibiting hormone (mih). reduction or cessation of mih release from the sinus gland in the eyestalk, probably due to environmental cues, is one of possibly several signals for an increase of edysteroid production and subsequently enhancement of 20-hydroxyecdysone (20e) levels in the hemolymph. the present study asks the question whether the 20e peak in premoult stages d2/d3 is explained solely bythe cessat ... | 1999 | 10398338 |
| combination of peptide profiling by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and immunodetection on single glands or cells. | the combination of two sensitive and powerful analytical techniques on the same biological sample was examined: (i) matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (maldi-tof ms), which gives informative peptide profiling on complex samples such as organs or cells; (ii) immunological tools such as enzyme-linked immunosorbent assay (elisa) and immunocytochemistry to probe for specific peptides in biological extracts or cells. the cellular expression of the two precurs ... | 1998 | 9599581 |
| ultrastructural changes of the microvillar cytoskeleton in the photoreceptor of the crayfish orconectes limosus related to different adaptation conditions. | in the retina of crayfish microvilli of seven of the eight photoreceptor cells build highly organized structures, the rhabdoms. cytoskeletal elements inside the microvilli were investigated in conventional and slightly extracted electron microscopical preparations. in conventional preparations the ultrastructure of these cytoskeletal elements depended on the adaptational state of the animal. they appeared as central filament-like structures inside each microvillus when dark-adapted retinae were ... | 1995 | 18621305 |
| structure-activity relationships of the crustacean myotropic neuropeptide orcokinin. | orcokinin (ok, nfdeidrsgfgfn) was recently identified from the crayfish, orconectes limosus, as a potent hindgut-stimulating factor (14). to assess the importance of structural features of the peptide involved in effective ligand-receptor interactions, synthetic analogues of orcokinin were tested in the hindgut bioassay. tests with n- and c-terminal-truncated analogues and the c-terminal-amidated analogue (ok-nh2) demonstrate that changes at the c-terminus interfere less with biological activity ... | 1995 | 7784249 |
| cloning and expression of two crustacean hyperglycemic-hormone mrnas in the eyestalk of the crayfish orconectes limosus. | crustacean hyperglycemic hormone (chh) is a multifunctional neurohormone produced in the eyestalk of crustaceans and is primarily involved in the regulation of carbohydrate metabolism. in several crustacean species, chh isoforms with identical amino acid sequences and molecular masses, but with different chromatographic elution patterns, are synthesized. to obtain sequence information on the chh preprohormone in the crayfish orconectes limosus we isolated two full-length cdnas encoding two struc ... | 1994 | 7925379 |
| comparison of directional selectivity in identified spiking and nonspiking mechanosensory neurons in the crayfish orconectes limosus. | we have recorded electrical activity from two identified synaptically coupled mechanosensory interneurons in the abdominal nervous system of the crayfish orconectes limosus and have studied their responses to constant-velocity water-jet stimuli presented from different directions. the two neurons, the ascending caudal photoreceptor (cpr) and the local directionally selective neuron, responded preferentially to stimuli delivered ipsilaterally to their dendritic input regions. both neurons feature ... | 1994 | 7517037 |
| structure and localization of mrna encoding a pigment dispersing hormone (pdh) in the eyestalk of the crayfish orconectes limosus. | the pigment-dispersing hormone (pdh) is produced in the eyestalks of crustacea where it induces light-adapting movements of pigment in the compound eye and regulates the pigment dispersion in the chromatophores. to study this hormone at the mrna level, we cloned and sequenced cdna encoding pdh in the crayfish orconectes limosus. the structure of the pdh preprohormone consists of a signal peptide, a pdh precursor-related peptide (pprp) and the highly conserved pdh peptide at the carboxy-terminal ... | 1993 | 8477858 |
| orcokinin: a novel myotropic peptide from the nervous system of the crayfish, orconectes limosus. | a myotropic peptide, named orcokinin, was isolated from approximately 1200 abdominal nerve cords of the crayfish, orconectes limosus. its amino acid sequence was determined as follows: asn-phe-asp-glu-ile-asp-arg-ser-gly-phe-gly-phe-asn. this structure was confirmed by synthesis. there is no sequence similarity to any known neuropeptide. orcokinin exhibits high potency on the crayfish hindgut, enhancing both frequency and amplitude of spontaneous contractions. the threshold of biological activit ... | 2008 | 1480511 |
| isolation of the rhabdomeral microvillar cytoskeleton of the crayfish (orconectes limosus) photoreceptor by a crosslinking reagent. | 1. rhabdomeral microvilli of photoreceptor cells of invertebrates contain a labile central cytoskeleton. for stabilization of the rhabdomeral cytoskeleton of the crayfish orconectes limosus the crosslinking reagent suberic acid bis (n-hydroxysuccinimide ester) was used. 2. it was found that this crosslinking reagent can be successfully used to stabilize and isolate the microvillar cytoskeleton of crayfish photoreceptors. 3. after detergent treatment cytosolic proteins and the cell membranes were ... | 1992 | 1526132 |
| evidence for a pathway of distal screening pigment granules across the basement membrane of the crayfish photoreceptor. | the distal pigment cells of orconectes limosus contain two layers of large electron lucent vacuoles that are separated by layers of small right-angled platelets adjacent to the crystalline cones. the crystalline cones of the dioptric apparatus of this species have evaginations into the distal pigment cell cytoplasm. in photoreceptors of orconectes limosus and procambarus clarkii a dark pigment accumulation site was detected just distal to the basement membrane at the edges of each retina. these ... | 2009 | 1418243 |
| effects of chloroquine on the photosensory membrane turnover and the ultrastructure of lysosome-related bodies of the crayfish photoreceptor. | the effect of chloroquine in combination with bright light on the ultrastructure of crayfish (orconectes limosus r.) photoreceptors was investigated in vivo. chloroquine had several effects upon the crayfish retina. multivesicular bodies (mvb) that are involved in lysosomal degradation of photosensory membrane were altered in ultrastructure. mvb frequently contained smaller mvb in a state of more advanced membrane degradation. additionally screening pigment-like granules appeared in mvb. mvb acc ... | 2013 | 1418239 |
| the effect of neuropeptides on the erg of the crayfish orconectes limosus. | ccap (crustacean cardioactive peptide), proctolin, fmrfamide, met- and leu-enkephalin, substance p, rpch (red pigment concentrating hormone) and pdh (pigment dispersing hormone) were applied to the isolated retina of the crayfish orconectes limosus. changes in light sensitivity, measured as changes of the amplitude of the electroretinogram (erg) were observed after application of rpch, pdh and ccap. rpch caused an increase of the erg amplitude to 133% of its reference value whereas pdh and ccap ... | 2009 | 1590891 |
| peroxidase and tyrosinase are present in secondary lysosomes that degrade photosensory membranes of the crayfish photoreceptor: possible role in pigment granule formation. | three enzymes (acid phosphatase, peroxidase, and tyrosinase) were localized by electron microscopy within the retina of crayfish orconectes limosus. peroxidase activity was observed only in lamellar bodies, which are secondary lysosomes and degrade photosensory membrane. after h2o2 was omitted from the reaction medium, peroxidase activity in lamellar bodies was partly inhibited but was not missing completely. after addition of sodium pyruvate, which inhibits endogenous generation of h2o2, staini ... | 1991 | 1667820 |
| detection of mrna encoding crustacean hyperglycemic hormone (chh) in the eyestalk of the crayfish orconectes limosus using non-radioactive in situ hybridization. | a non-radioactive in situ hybridization procedure for the localization of the mrna encoding the crustacean hyperglycemic hormone (chh) in the eyestalk of the crayfish orconectes limosus has been developed. based on the partial amino acid sequence of chh, polymerase chain reactions were performed to generate complementary dna (cdna) clones encoding chh. non-radioactively labelled probes derived from the cdna sequence were used to establish suitable conditions in terms of tissue fixation and pretr ... | 1991 | 2067718 |
| annexins as regulators of invertebrate phototransduction. | two proteins from crayfish (orconectes limosus) retinae bind ca(2+)-dependently to phospholipid membranes and crossreact with an antibody against calelectrin (annexin iv). these proteins (p48 and p40) are prominent substrates for the protein carboxyl methyl transferase (pcmt) which we propose to be an intracellular protein crosslinking enzyme. methylation and consequent crosslinking of p40 and p48 to the cytoskeleton or to the plasma membrane seem to be regulated by phosphorylation. in vivo inhi ... | 1991 | 1839808 |
| further evidence for synthesis of screening pigment granules involved in the photosensory membrane turnover of the crayfish photoreceptor. | photosensory membrane degradation in crayfish occurs at first in multi-vesicular bodies (mvbs) and then, with the aid of lysosomal enzymes, in lysosome related lamellar bodies. in organ culture experiments with the isolated crayfish retina (orconectes limosus) small screening pigment-like granules became visible under the electron microscope in such lamellar bodies and suggested a possible relation of photosensory membrane degradation and screening pigment granule synthesis. chloroquine, an inhi ... | 1990 | 2101928 |
| stretch-activated current through single ion channels in the abdominal stretch receptor organ of the crayfish. | single stretch-activated ion channels were studied on the soma and primary dendrites of stretch receptor neurons of the crayfish orconectes limosus. when the membrane of the patch was deformed by applying suction to the pipette, a marked nonlinear increase in single-channel activity could be observed in two types of channels. these were indistinguishable on the basis of their single-channel conductances but differed in their voltage range of activation. one type showed strong inward rectificatio ... | 1989 | 2482327 |
| new types of synaptic connections in crayfish stretch receptor organs: an electron microscopic study. | the synaptic input to crayfish (orconectes limosus) stretch receptor neurons, and the synaptic interactions between the inhibitory and excitatory efferents were analysed by electron microscopy of serial sections. several novel types of synaptic connections have been observed: (i) inhibitory synaptic input on the axon hillock and initial axon segment; (ii) serial synaptic terminals on the sensory cell body; (iii) simultaneous synaptic contacts of the same inhibitory terminal with sensory dendrite ... | 1987 | 3694235 |
| immunocytochemical evidence for the gabaergic innervation of the stretch receptor neurons in crayfish. | the gabaergic innervation of the stretch receptor neurons of the crayfish orconectes limosus has been investigated by means of light- and electron microscope immunocytochemistry using an antibody to gaba. both whole-mount preparations and post-embedding semithin sections revealed a massive gabaergic innervation of both the slowly and the fast adapting receptor neurons. the stretch receptor organ is supplied by one principle gaba-immunoreactive axon, which gives off several branches that innervat ... | 1987 | 3683849 |
| the hemopoietic character of the "cephalic gland" in the crayfish orconectes limosus. | topographical, histological, and radioimmunological reinvestigations of the "cephalic gland" in the head of the crayfish orconectes limosus demonstrated that this tissue is not of an endocrine nature. it is a part of the hemopoietic tissue and does not produce ecdysteroids. | 1983 | 6628973 |
| immuno-electron-microscopic evidence of ecdysteroids in y-organ of orconectes limosus (crustacea, decapoda). | ecdysone was demonstrated by ultrastructural immunocytochemistry to be present in the mitochondria of the y-organs of the crayfish orconectes limosus. this is in remarkable contrast to the prothoracic glands of insects and suggests substantial differences in the biosynthesis of the same hormone, ecdysone, in crustaceans and insects. | 1983 | 6352042 |
| characterization of cytoplasmic ecdysteroid receptors in the hypodermis of the crayfish, orconectes limosus. | [3h]ecdysone, [3h]20-oh-ecdysone and [3h]ponasterone a were specifically bound by the 120 000 g supernatant of the homogenate from crayfish hypodermis. according to the hplc test, the bound hormone was not metabolized. analysis of the cytosol receptor by sucrose-density-gradient centrifugation, gel filtration and enzymatic degradation revealed the protein character of the receptor, a molecular weight of 70 000-80 000 d, and 5s. the binding capacity was rapidly lost after treatment with n-ethyl-m ... | 1981 | 6276248 |
| demonstration of three different types of chemosensitive units in the crayfish claw using a computerized evaluation. | the different types of single units, sensitive either to amino acids, amines or 'pyridines' were found in afferent neurones in the claw of orconectes limosus. the shape of action potentials and the pattern of nerve impulse discharge were characteristic for each type. a computer program used in simultaneous recordings from several units selects up to four units according to spike amplitudes and establishes post-stimulus-time histograms, time interval histograms and average time courses of action ... | 1980 | 7052464 |
| single unit analysis of mechano- and chemosensitive neurones in the crayfish claw. | discharges from single sensory neurones originating in two different hair structures on the chelae of the crayfish orconectes limosus were recorded. mechanosensitive units responded to flow alteration or the deflection of single large setae. chemosensitive units were activated by fish extract in linear dependence on the logarithm of concentration of the chemoexcitant. mechano- and chemosensitive units differed with regard to the amplitudes of their action potentials and the time distribution of ... | 1980 | 7052463 |
| [structure and innervation of the abdominal stretch receptors in the crayfish orconectes limosus (raf.)]. | | 1980 | 6253351 |
| the ultrastructure of a hitherto unrecognized gland, the cephalic gland in the head of orconectes limosus which produces ecdysteroids. | | 1979 | 520812 |
| alterations of crossbridge angle induced by beta, gamma-imido-adenosine-triphosphate. electron microscope and optical diffraction studies on myofibrillar fragments of abdominal muscles of the crayfish orconectes limosus. | the molecular basis of muscle contraction is thought to consist of cyclic movements of parts of the myosin molecules (crossbridges). unitl now different states of the proposed crossbridge cycle could be stablilized and demonstrated by electron microscopy only in the case of highly specialized insect flight muscles. in this paper evidence is presented that it is also possible to induce crossbridge positions corresponding to the rigor [16] and the pseudorelaxed state [3] in non-insect muscles. hom ... | 1979 | 467464 |
| tracing of neurosecretory neurons in crayfish optic ganglia by cobalt iontophoresis. | the axonal connections between the medulla terminalis ganglionic x-organ (mtgxo) and the sinus gland are traced by iontophoretic application of cobalt dye to the neurosecretory system in the eyestalks of the crayfish, orconectes limosus. the mtgxo consists of about 15 large perikarya, forming a distinct subgroup of neurosecretory cells in the medulla terminalis and giving rise to a prominent fibre bundle. additional axons reaching the sinus gland from the medulla interna, the medulla externa and ... | 1978 | 728967 |
| [na-k ionic pump and spike adaptation in the slowly and rapidly adapting stretch receptor neuron of the crayfish orconectes limosus (raf.)]. | a very important cause of the spike adaptation in the slowly adapting stretch receptor neuron (sn1) is the na-k ionic pump. an increasing inhibition of the ionic pump, produced by gradual reduction of the external k+-concentration or application of rising doses of ouabain, is correlated with an adequate diminution of frequency decay. but even high concentrations of ouabain (10(-3) -- 5 . 10(-3) m) can not completely abolish the spike adaptation. immediately after the onset of a current step the ... | 1978 | 754423 |
| [frequency response of the abdominal stretch receptor neurons of the crayfish orconectes limosus (raf.) to intracellular current stimulation]. | in the slowly adapting stretch receptor neurons the temporal decline of the impulse frequency in response to intracellular current stimulation can be interpreted--apart from the high initial overshoot--by the sum of two exponential functions with time constants of approximately 1 and 10 s. in the rapidly adapting cells the discharge frequency decays--after only a little initial overshoot by current step stimulation--nearly rectilinear with about 8 imp./s2 and stops suddenly mostly in the range o ... | 1978 | 747044 |