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toxic and heavy metals as a cause of crayfish mass mortality from acidified headwater streams.mining activities are responsible for high concentrations of metals in river networks in many parts of the world. mining activities and the resulting high loads of heavy metals interact with intensive acid rain, and often have great consequences for biodiversity. however, considering the frequently episodic nature of these heavy acid rains, there is little detailed evidence of direct impacts. in 2011 we observed a massive mortality of noble crayfish and stone crayfish in padrťsko special area of ...201728108890
aphanomyces astaci isolate from latently infected stone crayfish (austropotamobius torrentium) population is virulent.aphanomyces astaci infection is the cause of crayfish plague in european crayfish. here the virulence of an a. astaci as strain isolated from apparently healthy stone crayfish (austropotamobius torrentium) from slovenia was compared to that of the psl-puujärvi a. astaci isolate in 3 crayfish species: noble crayfish (astacus astacus), signal crayfish (pacifastacus leniusculus) from finland and stone crayfish from slovenia. all 3 crayfish species were challenged with psi-puujärvi a. astaci and suc ...201728716442
monitoring of noble, signal and narrow-clawed crayfish using environmental dna from freshwater samples.for several hundred years freshwater crayfish (crustacea-decapoda-astacidea) have played an important ecological, cultural and culinary role in scandinavia. however, many native populations of noble crayfish astacus astacus have faced major declines during the last century, largely resulting from human assisted expansion of non-indigenous signal crayfish pacifastacus leniusculus that carry and transmit the crayfish plague pathogen. in denmark, also the non-indigenous narrow-clawed crayfish astac ...201728654642
high-resolution structural and elemental analyses of calcium storage structures synthesized by the noble crayfish astacus astacus.during premolt, crayfish develop deposits of calcium ions, called gastroliths, in their stomach wall. the stored calcium is used for the calcification of parts of the skeleton regularly renewed for allowing growth. structural and molecular analyses of gastroliths have been primarily performed on three crayfish species, orconectes virilis, procambarus clarkii, and more recently, cherax quadricarinatus. we have performed high-resolution analyses of gastroliths from the native noble crayfish, astac ...201627612582
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 ...201627225308
founder event and its effect on genetic variation in translocated populations of noble crayfish (astacus astacus).establishing translocated populations is a common process to preserve and maintain genetic diversity of threatened species. in 2001, three translocated populations of noble crayfish (astacus astacus) were established in the czech republic, founded by either adult or juvenile individuals from three particular source populations. we assessed genetic diversity at seven microsatellite loci after one decade (assumed three generations) from establishment. although the translocated populations exhibite ...201626077200
de novo assembly and annotation of the freshwater crayfish astacus astacus transcriptome.we generated rna-seq data to assemble the transcriptome of the noble crayfish (astacus astacus) from four combined tissues (abdominal muscle, hepatopancreas, ovaries, green glands). a total of 194 million read pairs with a length of 100 bp were generated. the transcriptome was assembled de novo using trinity software, producing 158,649 non-redundant transcripts. lowly expressed transcripts were filtered out leaving 45,415 transcripts of which 14,559 were found to contain open reading frames with ...201626988698
prevalence of the pathogen aphanomyces astaci in freshwater crayfish populations in croatia.the oomycete aphanomyces astaci is an obligate crayfish parasite that co-evolved with american crayfish species, and they therefore generally live in a balanced relationship. on the contrary, european native crayfish are highly susceptible to a. astaci, and infestation with it causes development of the lethal disease termed crayfish plague. until now, 5 a. astaci strains have been described from the freshwater crayfish present in europe. in this study we aimed to investigate the occurrence of th ...201626865234
subcellular localization of calcium deposits in the noble crayfish astacus astacus spermatophore: implications for post-mating spermatophore hardening and spermatozoon maturation.the freshly ejaculated spermatophore of crayfish undergoes a hardening process during post-mating storage on the body surface of female. the ultrastructural distribution of calcium deposits were studied and compared in freshly ejaculated and post-mating noble crayfish spermatophores, using the oxalate-pyroantimonate technique, to determine possible roles of calcium in post-mating spermatophore hardening and spermatozoon maturation. small particles of sparsely distributed calcium deposits were vi ...201626817519
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 ...201526410255
label-free protein quantification in freshly ejaculated versus post-mating spermatophores of the noble crayfish astacus astacus.crayfish spermatophores are deposited on the body surface of the female during mating and remain there for a period of time before fertilization ensues. post-mating changes in protein expression level in the noble crayfish astacus astacus spermatophore were quantified. in-gel digestion and high resolution mass spectrometry were used for label-free protein quantification. one hundred twelve proteins were identified in the spermatophore of noble crayfish. after 7 days of storage on the body of the ...201525871631
ultrastructure of egg activation and cortical reaction in the noble crayfish astacus astacus.morphological changes in the gamete of female noble crayfish at four developmental stages were studied. mature ovarian oocytes are enclosed by the first envelope that consists of two layers. numerous pores are visible on the surface of the outer layer of this envelope and the inner layer contains bottlebrush-shaped objects. three types of vesicles, including some that are highly and moderately electron-dense and some multi-layered, occur in the cortex of the oocyte. in freshly ovulated eggs, the ...201525464149
some like it hot: thermal tolerance and oxygen supply capacity in two eurythermal crustaceans.thermal sensitivity of the cardiorespiratory oxygen supply capacity has been proposed as the cardinal link underlying the upper boundary of the temperature niche in aquatic ectotherms. here we examined the evidence for this link in two eurythermal decapods, the giant tiger shrimp (penaeus monodon) and the european crayfish (astacus astacus). we found that both species have a temperature resistant cardiorespiratory system, capable of maintaining oxygen delivery up to their upper critical temperat ...201526030412
dose-dependent mortality of the noble crayfish (astacus astacus) to different strains of the crayfish plague (aphanomyces astaci).several reports of the european crayfish species carrying a latent infection of the crayfish plague (aphanomyces astaci) have emerged and the discussion has focused especially on the lowered virulence of as-genotypes behind decreased mortality. the aim of this study was to compare the killing rate of different a. astaci strains in controlled infection experiments. two separate infection experiments with three a. astaci strains (ueft2b (as), evira6462/06 (as) and uef8866-2 (psi)) were made to com ...201424184185
molecular detection and genotyping of aphanomyces astaci directly from preserved crayfish samples uncovers the norwegian crayfish plague disease history.aphanomyces astaci causes crayfish plague in european freshwater crayfish, but most historical epizootics lack agent isolation and identification. although declared as crayfish plague outbreaks by the norwegian competent authorities, only presumptive diagnoses without agent isolation exist from norwegian epizootics until 2005. molecular methods now allow both a. astaci detection and genotype determination from preserved samples. we therefore aimed to (1) investigate molecularly if a. astaci was ...201425124447
recovery of hafnia alvei from diseased brown trout, salmo trutta l., and healthy noble crayfish, astacus astacus (l.), in bulgaria.hafnia alvei was isolated in bulgaria from healthy noble crayfish, astacus astacus (l.), and then from farmed diseased brown trout, salmo trutta l., with signs of haemorrhagic septicaemia. the isolates were identified initially with conventional phenotyping and commercial merlin micronaut and api 20e rapid identification systems, followed by sequencing of the 16s rrna gene. hafnia alvei bt1, bt2 and aa4 were of low virulence to rainbow trout and brown trout, although cytotoxicity was demonstrate ...201424422558
resistance to the crayfish plague pathogen, aphanomyces astaci, in two freshwater shrimps.aphanomyces astaci, the causal agent of the crayfish plague, has recently been confirmed to infect also freshwater-inhabiting crabs. we experimentally tested the resistance of freshwater shrimps, another important decapod group inhabiting freshwaters, to this pathogen. we exposed individuals of two asian shrimp species, macrobrachium dayanum and neocaridina davidi, to zoospores of the pathogen strain isolated from procambarus clarkii, a known a. astaci carrier likely to get into contact with shr ...201425064254
[neutrophin ngf protects glial cells, but not stretch receptor neurons of the crayfish astacus astacus from photooxidative stress]. 201418038644
timing and quantifying aphanomyces astaci sporulation from the noble crayfish suffering from the crayfish plague.aphanomyces astaci sporulation is crucial for the spreading potential of this disease agent. for the first time, we are reporting timing and quantity of a. astaci spores released from noble crayfish (astacus astacus) suffering from crayfish plague under practical aquatic conditions. we infected nine noble crayfish with a. astaci psi-genotype and maintained them in individual 8l tanks. spores (zoospores and cysts) were quantified from water samples (3 × 1 ml) taken every 12h over 10 d using a. as ...201323102971
lc-ms analysis with thiol derivatization to differentiate [dhb(7)]- from [mdha(7)]-microcystins: analysis of cyanobacterial blooms, planktothrix cultures and european crayfish from lake steinsfjorden, norway.kinetic studies showed that [asp(3), dhb(7)]mc-rr reacted with mercaptoethanol hundreds of times more slowly than mc-rr and a range of other [mdha(7)]-containing microcystin congeners. the difference in reaction rate was sufficiently large that derivatization of microcystin-containing samples with mercaptoethanol, followed by lc-ms analysis, clearly discriminated between microcystins containing the isobaric [dhb(7)]- and [mdha(7)]-groups. application of this approach, using lc-ms with both-ion t ...201323531156
effects of climate change, invasive species, and disease on the distribution of native european crayfishes.climate change will require species to adapt to new conditions or follow preferred climates to higher latitudes or elevations, but many dispersal-limited freshwater species may be unable to move due to barriers imposed by watershed boundaries. in addition, invasive nonnative species may expand into new regions under future climate conditions and contribute to the decline of native species. we evaluated future distributions for the threatened european crayfish fauna in response to climate change, ...201323531056
comparative ultrastructure of the spermatozoa of three crayfish species: austropotamobius torrentium, pacifastacus leniusculus, and astacus astacus (decapoda: astacidae).this study reports about the spermatozoal ultrastructure of three species of astacid crayfish, i.e., the stone crayfish austropotamobius torrentium, signal crayfish pacifastacus leniusculus, and noble crayfish astacus astacus. the acrosome is a cup shaped and electron-dense structure at the anterior of the spermatozoon and comprises three layers of differing electron densities filled with parallel filaments that extend from the base to the apical zone. the acrosome was significantly longer in a. ...201323475696
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 ...201323425502
lunar-rhythmic molting in laboratory populations of the noble crayfish astacus astacus (crustacea, astacidea): an experimental analysis.juvenile noble crayfish, astacusastacus (crustacea, astacidea) in the second year of age were kept in the laboratory for a twelve-month period under continuing "summer conditions" (ld 16:8, 19°c). molting processes in this population could be synchronized by artificial moonlight cycles. peaks of exuviations occurred at "new moons". males showed a slightly higher degree of synchronization than females. a phase-shift of the artificial lunar cycle in relation to the natural cycle resulted in a corr ...201323840899
distribution and epidemiology of genotypes of the crayfish plague agent aphanomyces astaci from noble crayfish astacus astacus in finland.the crayfish plague agent aphanomyces astaci was isolated from 69 noble crayfish astacus astacus samples in finland between 1996 and 2006. all isolates were genotyped using randomly amplified polymorphic dna-polymerase chain reaction (rapd-pcr). altogether, 43 isolates belonged to the genotype group of astacus strains (as), which is assumed to represent the genotype originally introduced into europe around 1860 and into finland in 1893. there were 26 crayfish plague isolates belonging to the gro ...201323574706
aphanomyces astaci in wild crayfish populations in slovenia: first report of persistent infection in a stone crayfish austropotamobius torrentium population.all 5 crayfish species inhabiting slovenian freshwaters, of which 3 are indigenous crayfish species (ics: astacus astacus, austropotamobius pallipes, and a. torrentium) and 2 are non-indigenous (nics: pacifastacus leniusculus and cherax quadricarinatus), were inspected for the presence of aphanomyces astaci, the causative agent of crayfish plague. wild crayfish populations showing no clinical signs of infection were inspected using a. astaci-specific real-time pcr. in addition, a conventional pc ...201323548366
fusarium avenaceum causes burn spot disease syndrome in noble crayfish (astacus astacus).burn spot disease has been causing epidemics both in the estonian mainland and in saaremaa island in the threatened noble crayfish (astacus astacus) stocks. to study the cause of the disease, we isolated several fusarium spp. from estonian noble crayfish (a. astacus) populations suffering from burn spot disease syndrome. we first identified fungi directly from melanised cuticle by their its sequences. then we isolated fusarium spp. from melanised spots of crayfish showing burn spot disease sympt ...201323557716
differing virulence of aphanomyces astaci isolates and elevated resistance of noble crayfish astacus astacus against crayfish plague.crayfish plague epidemics (caused by aphanomyces astaci) have been causing population collapses among native european crayfish stocks since the late 1800s. recent indirect and direct evidence has shown that its virulence has been variable, with native european crayfish even acting as carriers. we tested the differences in a. astaci virulence under experimental conditions using both psi- and as-genotypes with 3 finnish noble crayfish astacus astacus populations. we infected crayfish with adjusted ...201223269387
potent infection reservoir of crayfish plague now permanently established in norway.noble crayfish astacus astacus is threatened in europe due to invasive crayfish carrying the crayfish plague agent aphanomyces astaci. norway is among the last countries in which the introduction of non-indigenous crayfish has been limited through strict legislation practices. however, north american signal crayfish pacifastacus leniusculus were recently discovered in a water-course that has been repeatedly hit by the plague. we mapped the distribution and relative density (catch per unit effort ...201122235597
detection and quantification of the crayfish plague agent in natural waters: direct monitoring approach for aquatic environments.aphanomyces astaci, a specialised parasite of north american freshwater crayfish, is the disease agent of crayfish plague that is lethal to european freshwater crayfish. the life cycle of a. astaci has been inferred from experimental laboratory studies, but less is known about its natural sustainability and ecology. to address such questions, tools for monitoring of a. astaci directly in aquatic environments are needed. here, we present an approach for detecting and quantifying a. astaci directl ...201121797031
strongyloides stercoralis excretory/secretory protein strongylastacin specifically recognized by ige antibodies in infected human sera.the infective, microscopic strongyloides stercoralis larvae in contaminated soil can penetrate human skin with the help of excretory/secretory proteases. these proteases play a critical role in infection and transmigration of the parasite to the intestines. strongylastacin is similar to astacin (from the digestive gland of the crayfish astacus astacus), a multi-domain protein with a signal peptide, a pro-enzyme, a catalytic domain containing the zinc binding consensus astacin family signature se ...201121204942
the ionic mechanism of intracellular ph regulation in crayfish muscle fibres.the ionic mechanism of intracellular ph (phi) regulation was investigated in isolated muscle fibres of the carpopodite adductor in the crayfish astacus fluviatilis by electrophysiological means with ph, na+ and cl- -sensitive liquid ion exchanger micro-electrodes. in eighty-six cells a mean phi of 7.14 +/- 0.12 (s.d.) at a membrane potential of--79.7 +/- 3.4 mv was found under control conditions which is about one ph unit more alkaline than predicted from passive distribution and indicates the p ...20113091812
a general mathematical model of transduction events in mechano-sensory stretch receptors.crayfish (astacus astacus) muscle stretch receptors show strong homology to mammalian muscle spindles and bipolar neurons in d. melanogaster. all are typical, non-ciliated, stretch-sensitive, afferent neurons. such receptors are observed in many species and perform an important sensory role. however, they are poorly characterised. a previous study reported a bio-mechanical and behavioural model of a. astacus stretch receptors, which used the principles of elasticity and tension in a spring to de ...201122149673
proenzyme structure and activation of astacin metallopeptidase.proteolysis is regulated by inactive (latent) zymogens, with a prosegment preventing access of substrates to the active-site cleft of the enzyme. how latency is maintained often depends on the catalytic mechanism of the protease. for example, in several families of the metzincin metallopeptidases, a "cysteine switch" mechanism involves a conserved prosegment motif with a cysteine residue that coordinates the catalytic zinc ion. another family of metzincins, the astacins, do not possess a cystein ...201020202938
cloning, characterisation and heterologous expression of an astacin metalloprotease, sc-ast, from the entomoparasitic nematode steinernema carpocapsae.steinernema carpocapsae is a parasitic nematode that is high virulent to insects. the parasitic juvenile reaches the insect haemocoelium by passing through mid-gut barriers and develops there. during invasion, the nematode was predicted to express a large set of proteases, including metalloproteases, one of which was sequenced and expressed in this work. a 1583-nucleotide cdna encoding a putative metalloprotease containing a 28-aa signal peptide, a 79-aa propeptide and a 311-aa mature protease w ...201020670659
a quantitative taqman mgb real-time polymerase chain reaction based assay for detection of the causative agent of crayfish plague aphanomyces astaci.here we present the development and first validation of a taqman minor groove binder (mgb) real-time polymerase chain reaction (rt-pcr) method for quantitative and highly specific detection of aphanomyces astaci, the causative agent of crayfish plague. the assay specificity was experimentally assessed by testing against dna representative of closely related oomycetes, and theoretically assessed by additional sequence similarity analyses comparing the primers and probe sequences to available sequ ...200919201113
incomes, attitudes, and occurrences of invasive species: an application to signal crayfish in sweden.this article analyzes and carries out an econometric test of the explanatory power of economic and attitude variables for occurrences of the nonnative signal crayfish in swedish waters. signal crayfish are a carrier of plague which threatens the native noble crayfish with extinction. crayfish are associated with recreational and cultural traditions in sweden, which may run against environmental preferences for preserving native species. econometric analysis is carried out using panel data at the ...200918946699
isolation and characterization of 11 novel microsatellite dna markers in the noble crayfish, astacus astacus. 200918786153
[synthesis of nucleic acids and localization of atrial natriuretic peptide in the crayfish haemocytes].three types of cells circulate in haemolymph of the crayfish astacus astacus: agranular haemocytes (hcs i), small-granule haemocytes (hcs ii) and large-granule haemocytes (hcs iii). their proliferation, differentiation and function remain poorly understood. by means of light and electron microscopic autoradiography using [3h]-thymidine, we have revealed that only hcs i are capable of dna synthesis and mitosis whereas hcs ii and hcs iii are replicatively inactive. to determine whether the hcs i a ...200818664126
a large discoidal lipoprotein present in only one of two closely related crayfish.the hemolymph lipoproteins of two european freshwater crayfish, astacus astacus and astacus leptodactylus, were isolated and characterized. the former species possesses two sex-independent lipoproteins, which can be related to the formerly described high-density lipoprotein (hdl)/beta-glucan binding protein and very high-density lipoprotein/clotting protein from other crustaceans. the latter species, however, contains an additional third lipoprotein with a unique structure. it is a large discoid ...200818415110
[cilia of hair receptors in the claw of the crayfish astacus astacus]. 20084647991
[heart activity of crayfish astacus astacus in early ontogenesis]. 200812244679
[neurophysiologic patterns of movement control in free-moving astacus astacus crayfish].studies have been made on the neuronal organization of muscular control in the dactylopodite during grasping the food by the claw, holding it by the dactyls, tranasportation to the mouth opening area and to the perioral organs. it was shown that in coordination relationships of efferent structures which control muscular efforts of the dactylopodite during realization of foodgrasping movements, the important role is played by afferent influences from hairy mechanoreceptors located on the inner su ...20087424306
[effect of sensory input parameters on efferent output of spike activity of river crayfish neurons].studies have been made of the influence of localization, direction, frequency and other parameters of mechanostimulation of the cuticular receptors on the impulse activity of efferent neurones innervating claw muscles in the crayfish astacus astacus and a. leptodactylus. the results obtained are discussed from a standpoint of the possibility of central organization of sensory-motor relationships, which involves modulating afferent influences on efferent neuronal activity.20087424305
mechanotransduction and the crayfish stretch receptor.mechanotransduction or mechanosensitivity is found in almost every cell in all organisms from bacteria to vertebrates. mechanosensitivity covers a wide spectrum of functions from osmosensing, cell attachment, classical sensory mechanisms like tactile senses in the skin, detection of sound in hair cells of the hearing apparatus, proprioceptive functions like recording of muscle length and tension in the muscle spindle and tendon organ, respectively, and pressure detection in the circulation etc. ...200717612581
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 ...200617278707
molecular diagnostic methods for detection of thelohania contejeani (microsporidia), the causative agent of porcelain disease in crayfish.diagnosis of thelohania contejeani in the crayfish astacus astacus is currently based on observation of gross clinical signs--opaque appearance of the abdomen and whitish colouration of the musculature--and confirmed by microscopic examination of histological sections of muscle. we have developed 2 molecular diagnostic methods for sensitive and rapid detection of porcelain disease in its early stages: pcr and loop-mediated isothermal amplification (lamp). the pcr test utilises a primer based on ...200616724564
[architectonics of the neuropil of the last abdominal ganglion in the crayfish astacus astacus]. 20064440318
[the topography of the sensory fibers of the neuropile of the first thoracic ganglion of the crayfish astacus astacus]. 20064463630
[heart activity of the crayfish astacus astacus in various functional states]. 200611966202
[the behavioral reactions of fresh-water crayfish to sensory exposures: the autonomic components].sudden changes of the environment such as a short-lasting shadowing of an animal, placing of some small objects into the tank, light vibrations of the bottom etc. caused vegetative responses in the freely moving native crayfish astacus astacus and the american crayfish procambarus cubensis adapted for many generations to aquarium habitat. we observed mainly a sudden decrease of ecg-frequency correlated with similar changes in the electrical activity of the muscles moving the specific ventilatory ...20068135058
[the orienting reaction in invertebrates].there are described the changes in movement and autonomous activity of the freshwater crayfish upon the sudden changes of the environment. the judging the reaction was based on: 1) the observation of all available behavioral manifestations in the crayfish procambarus cubensis which has been in its "natural" habitat; 2) the recording of the electrical activity of the heart (ecg) and of the ventilatory appendages (scaphognathites; sgg) in freely moving astacus astacus and procambarus cubensis; 3) ...20067645326
[the behavioral reactions of fresh-water crayfish to sensory exposures: the motor components].responses to some distant stimuli which acted on the mechanosensory and visual systems and were close to natural ones were investigated in native crayfish astacus astacus and reared in aquaria american crayfish procambarus cubensis. the stimuli did not evoke immediate animal movements, however they induced short-latency emg reactions in walking leg and abdominal muscles as well as long-term changes in the background locomotor activity. considerable non-specificity of the so-called indifferent st ...20067597828
[characteristics of impulse trains in cells of the 6th abdominal ganglion of the crayfish astacus astacus]. 20064766461
identification of an astacin-like metallo-proteinase transcript from the infective larvae of strongyloides stercoralis.strongyloides stercoralis, an important nematode pathogen of humans, is transmitted by contact with soil contaminated with the microscopic larvae of the parasite. we determined the cdna sequence and deduced amino acid structure of a metallo-proteinase that is abundantly transcribed expressed by infective stage larvae of s. stercoralis. this deduced structure of the enzyme revealed a multi-domain protein that included an nh2-terminal peptidase. this peptidase consisted of a signal peptide, a pro- ...200515866474
effect of water temperature on the immune response and infectivity pattern of white spot syndrome virus (wssv) in freshwater crayfish.the susceptibility of two species of freshwater crayfish, pacifastacus leniusculus and astacus astacus, to white spot syndrome virus (wssv) by intramuscular injection was compared and the results show that both species are susceptible to wssv. the effect of water temperature on the development of white spot disease in crayfish was also studied. crayfish were exposed to different temperatures after wssv injection or oral exposure and the mortalities were recorded over a period of 45 days. no mort ...200415276606
detection of genomic dna of the crayfish plague fungus aphanomyces astaci (oomycete) in clinical samples by pcr.a diagnostic procedure, based on a polymerase chain reaction method (pcr) was developed to detect infection of crayfish with the oomycete aphanomyces astaci. a set of oligonucleotide primers was designed to specifically amplify a. astaci dna in the its region surrounding the 5.8s rdna gene. the pcr amplifies a 115bp amplicon. the specificity of the primers was demonstrated by testing on 27 a. astaci strains and against 20 non-a. astaci oomycetes and 5 fungal species. most of the non-a. astaci oo ...200415145505
host prophenoloxidase expression in freshwater crayfish is linked to increased resistance to the crayfish plague fungus, aphanomyces astaci.the crayfish plague (aphanomyces astaci) susceptible freshwater crayfish astacus astacus and the resistant species pacifastacus leniusculus were compared with respect to differential haemocyte count and expression of prophenoloxidase and peroxinectin. a major difference found was that resistant crayfish continuously produced high levels of prophenoloxidase (propo) transcripts and that these levels could not be further increased, whereas in susceptible crayfish propo transcript levels and resista ...200312713493
membrane currents in a calcium type muscle membrane under voltage clamp.four ionic current components were identified in the total membrane current recorded under voltage clamp conditions from the muscle membrane of the crayfish (astacus fluviatilis). the early inward current component is dependent on the presence of ca2+ ions, disappears in ca2+ free solutions and is insensitive to variaton of external na+ ions and to tetrodotoxin. the outward current consists of at least three components, an early, a late and a slow outward current. the outward currents are sensit ...2003153539
activation mechanism of pro-astacin: role of the pro-peptide, tryptic and autoproteolytic cleavage and importance of precise amino-terminal processing.astacin (ec 3.4.24.21) is a prototype for the astacin family and for the metzincin superfamily of zinc peptidases, which comprise membrane-bound and secreted enzymes involved in extracellular proteolysis during tissue development and remodelling. generally, metzincins are translated as pro-enzymes (zymogens), which are activated by removal of an n-terminal pro-peptide. in astacin, however, the mode of zymogen activation has been obscured, since the pro-form does not accumulate in vivo. here we r ...200212441103
biomarkers as diagnostic tools for evaluating effects of unknown past water quality conditions on stream organisms.the following biomarkers were investigated in stream populations of juvenile brown trout (salmo trutta f. fario) and gammarids (gammarus pulex) to determine if crayfish mortality could have been confounded by pollutants: (1) alterations of fish liver ultrastructure, (2) fish gill and kidney histopathology, (3) stress protein (hsp70) expression in fish liver and gills and in gammarids, and (4) changes in various blood parameters of brown trout. in addition, the following measurements were conduct ...200212521141
the environmental consequences of alien species in the swedish lakes mälaren, hjälmaren, vänern and vättern.twenty alien species have become established in the lakes mälaren, vänern, vättern and hjälmaren. intentional introductions include fish and the signal crayfish from north america, ornamental plants, and the canada goose. unintentional introductions include the crayfish plague introduced with infected crayfish, the zebra mussel, and chinese mitten crab introduced with ballast water. the introduction of pathogens and parasites, in particular the crayfish plague, to the lakes has had the greatest ...200111878025
activation of pro-astacin. immunological and model peptide studies on the processing of immature astacin, a zinc-endopeptidase from the crayfish astacus astacus.to contribute knowledge of the processing and activation of invertebrate proteolytic enzymes, we studied the metalloprotease astacin, a digestive enzyme from the freshwater crayfish astacus astacus (decapod crustacean). it is the prototype of the protein family of astacins, members of which occur in organisms from bacteria to man and are involved in a variety of physiological reactions. according to its genomic structure, astacin is produced as a zymogen [geier, g., jacob, e., stöcker, w. & zwil ...200111322872
sequence analysis of the ribosomal internal transcribed spacer dna of the crayfish parasite psorospermium haeckeli.two morphotypes of the crayfish parasite psorospermium haeckeli were isolated from 2 crayfish species of different geographical origin. the oval-shaped sporocysts were obtained from the epidermal and connective tissue beneath the carapace of the noble crayfish astacus astacus from sweden and finland. elongated spores were isolated from the abdominal muscle tissue of the red swamp crayfish procambarus clarkii from usa. to compare genetic divergence of 2 morphotypes of the parasite, the ribosomal ...200111710556
simultaneous experimental study of direct and direct plus trophic contamination of the crayfish astacus astacus by inorganic mercury and methylmercury.an experimental study was carried out to investigate direct and direct plus trophic contamination routes of the crayfish astacus astacus by inorganic mercury (hg(ii)) or methylmercury (mehg). direct exposure was based on low contamination conditions, 300 and 30 ng/l in the dissolved phase, respectively, during 30 d at 20 degrees c. trophic exposure was based on daily consumption of the asiatic clam corbicula fluminea, previously contaminated during 40 d with similar exposure conditions. the hg c ...200111392130
anion uptake and acid-base and ionic effects during isolated and combined exposure to hypercapnia and nitrite in the freshwater crayfish, astacus astacus.nitrite influx into crayfish showed saturation kinetics, supporting a carrier-mediated uptake. addition of 4,4'-diisothiocyanatostilbene-2,2'-disulfonate (dids: at 10(-5), 10(-4) and 10(-3) m) and bumetanide (at 10(-5) m and 10(-4) m) to the ambient water did not significantly affect nitrite influx. rather than suggesting that neither cl-/hco3- exchange nor k+/na+/2cl- cotransport were involved in the transport, this may reflect that the gill cuticle has a low permeability to the pharmacological ...200011128438
[response of membranes of mechanosensitive neurons in astacus astacus to the intracellular injections of solutions under pressure].injections of iso- and hypertonic solutions of some potassium salts caused an obvious depolarisation and reduction of electrical resistance in the crayfish slowly adapting stretch receptor neurones' membrane. this response could be eliminated with gadolinium. the stretch-activated channels in the crayfish stretch receptor neurone seem to be affected by an intracellular hydrostatic pressure.200011059023
comparative experimental study of cadmium and methylmercury trophic transfers between the asiatic clam corbicula fluminea and the crayfish astacus astacus.cadmium (cd) and methylmercury (mehg) trophic transfers were analyzed between the asiatic clam corbicula fluminea and the crayfish astacus astacus. metal bioaccumulation in crayfish was quantified after 5, 10, and 15 days of exposure via daily ingestion of soft bodies of c. fluminea, previously exposed during 7 days to cd (20 microg. l(-1)) and mehg (4 microg. l(-1)). bioaccumulation kinetics in the predator were investigated at organ and tissue levels: hemolymph, tail muscle, hepatopancreas, gi ...200010667929
on the eggs of an enigmatic nematode parasite encapsulated in the connective tissue of the european crayfish, astacus astacus in sweden. 20005720509
cdna cloning, bacterial expression, in vitro renaturation and affinity purification of the zinc endopeptidase astacin.astacin (ec 3.4.24.21) from the freshwater crayfish (astacus astacus) is a prototype for the metzincin superfamily and for the astacin family of zinc peptidases, enzymes which are involved in hatching processes, embryonic patterning and tissue remodelling. here we report on the cloning and overexpression in escherichia coli of an astacin cdna which was reverse-transcribed from crayfish midgut-gland mrna. a cdna construct based on this clone was generated which comprised the nucleotide sequence e ...199910585873
multiple mechanisms of block by the anesthetic isoflurane of a gamma-aminobutyric acid activated chloride channel in crayfish.outside-out patches were excised from the membrane of the deep extensor abdominal muscle (deam), containing gamma-aminobutyric acid (gaba)-activated chloride channels, in the crayfish astacus astacus. gaba and isoflurane (iso) were applied in pulses by a liquid filament switch, and their effects on the gaba-elicited chloride currents were investigated. application of iso alone elicited no current responses and pre-application of iso prior to gaba had no effects on the gaba-elicited current. co-a ...19989447713
action potential and sodium current in the slowly and rapidly adapting stretch receptor neurons of the crayfish (astacus astacus).action potentials (aps) and sodium current from the slowly and the rapidly adapting stretch receptor neurons in the crayfish (astacus astacus) were recorded with a two microelectrode voltage- and current-clamp technique. in the rapidly adapting neuron the aps had a duration of 3.2 +/- 0.2 ms (means +/- se) and an amplitude of 55.2 +/- 1.5 mv. in the slowly adapting receptor neuron aps had a duration of 4.1 +/- 0.2 ms and an amplitude 79.9 +/- 2.0 mv. aps in the rapidly adapting neuron had a larg ...19989772266
cloning and characterization of a cdna coding for astacus embryonic astacin, a member of the astacin family of metalloproteases from the crayfish astacus astacus.the astacin family of zinc endopeptidases was named after the digestive enzyme astacin isolated from the crayfish astacus astacus. employing a reverse transcription/pcr strategy with degenerate oligonucleotide primers specific for two signature seqences of the astacin family, we have isolated a 1602-bp cdna from embryos of developing a. astacus eggs, which was designated astacus embryonic astacin (aea). this cdna was found to code for an astacin-like protease domain which accounts for the n-term ...19989654081
extracellular ca2+ and its effect on acid extrusion in the crayfish stretch receptor neurone1. in the stretch receptor neurones of the crayfish astacus astacus, the intracellular ph (phi), the intracellular na+ concentration ([na+]i) and the membrane potential (em) were measured simultaneously using ion-selective and conventional microelectrodes. normal astacus saline (nas), and salines containing varying amounts of ca2+ (ca2+-nas) but of constant ionic strength, with na+, mg2+ or ba2+ as substituting ions, were used to investigate the effects of extracellular ca2+ concentration ([ca2+ ...19969319690
primary structures of decapod crustacean metallothioneins with special emphasis on freshwater and semi-terrestrial species.cadmium injections induced only a single form of metallothionein (mt) in the midgut gland of potamon potamios, whereas the same treatment induced two isoforms in astacus astacus. the only difference between the two latter isoforms was that one had an extra n-terminal methionine residue. mt from p. potamios showed structural differences from other decapod crustacean mts. it contained a gly-thr motif at positions 8 and 8a, which had previously been found only in certain vertebrate and molluscan mt ...19968921011
characterization and molecular reaction scheme of a chloride channel expressed after axotomy in crayfish.the nerve to the deep extensor abdominal muscle (deam) in crayfish species astacus astacus, containing four excitatory and one inhibitory motor axons, was cut in the third segment on one side of the animal. the distal axon stump was not subject to phagocytosis but was present for months after the axotomy. the two lateral bundles of the deam were prepared 4-6 weeks after the axotomy. the gamma-aminobutyric-acid-(gaba-) activated chloride channel of these bundles was characterized by applying puls ...19968772138
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 ...19947814685
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 ...19947937311
trace elements in crayfish: regional differences and changes induced by cooking.the concentrations of pb, cd, zn, cu, ni, cr, mn, co, as, and se were determined in the abdominal muscle and hepatopancreas from raw and cooked crayfish of astacus astacus (l.) and pacifastacus leniusculus (dana), both of swedish origin. after cooking, the concentrations of cd, ni, and co in the hepatopancreas showed a decrease and the concentrations of pb, cu, and mn in the abdominal muscle showed an increase. metal and metalloid concentrations were also determined in the abdominal muscle and h ...19948311505
interactions among juveniles of two freshwater crayfish species and a predatory fish.two freshwater crayfish species, astacus astacus l. and pacifastacus leniusculus dana, co-occur in some swedish lakes. observational studies indicate that the introduced, north american species p. leniusculus may gradually replace the native a. astacus, but the mechanism behind the replacement is not known. this study examined the direct effects of interspecific competition between the crayfish, and indirect effects of competitive interactions and fish (european perch, perca fluviatilis l.) pred ...199428307005
a light emitting diode microspectrophotometer: intracellular ca2+ measurements in isolated stretch receptor.a microspectrophotometer was designed to measure absorbance changes in single cells. the device utilizes sequentially activated light emitting diodes (led) to provide different wave lengths of light. the instrument has the advantage of relative simplicity and less cost compared to other devices. the spectrophotometer was tested by measuring absorbance changes of the metallochromic ca2+ indicator arsenazo iii (aiii) injected into the crayfish (astacus astacus) stretch receptor. under the conditio ...19938377522
refined 1.8 a x-ray crystal structure of astacin, a zinc-endopeptidase from the crayfish astacus astacus l. structure determination, refinement, molecular structure and comparison with thermolysin.astacin, a 200 residue digestive zinc-endopeptidase from the crayfish astacus astacus l., is the prototype of the "astacin family", which comprises several membrane-bound mammalian endopeptidases and developmentally implicated regulatory proteins. large trigonal crystals of astacin were grown, and x-ray reflection data to 1.8 a resolution were collected. the astacin structure has been solved by multiple isomorphous replacement using six heavy-atom derivatives, and refined to a crystallographic r ...19938445658
implications of the three-dimensional structure of astacin for the structure and function of the astacin family of zinc-endopeptidases.astacin, a zinc-endopeptidase from the crayfish astacus astacus l., represents a structurally distinct group of metalloproteinases termed the 'astacin family'. this protein family includes oligomeric membrane-bound proteins with zinc proteinase domains found in rodent kidneys (meprins a and b) and human small intestine (n-benzoyl-l-tyrosyl-4-aminobenzoate hydrolase). another branch of this family comprises morphogenetically active proteins, which induce bone formation (human bone morphogenetic p ...19938508794
structure of astacin and implications for activation of astacins and zinc-ligation of collagenases.astacin, a digestive zinc-endopeptidase from the crayfish astacus astacus l., is the prototype for the 'astacin family', which includes mammalian metallo-endopeptidases and developmentally regulated proteins of man, fruitfly, frog and sea urchin. here we report the x-ray crystal structure of astacin, which reveals a deep active-site cleft, with the zinc at its bottom ligated by three histidines, a water molecule and a more remote tyrosine. the third histidine (his 102) forms part of a consensus ...19921319561
gaba-gated anion channels in intact crayfish opener muscle fibres and stretch-receptor neurons are neither activated nor desensitized by glutamate.the influence of glutamate on the gaba-activated cl- conductance was studied in the slowly adapting stretch-receptor neuron and dactylopodite opener muscle fibre of the crayfish (astacus astacus) using a two-microelectrode and a three-microelectrode voltage clamp, respectively. glutamate (0.5-1.0 mm) had no effect on the gaba-activated conductance in either preparation. this indicates that the availability of the inhibitory channels for activation of gaba is not influenced by glutamate. the pres ...19921378100
[interaction of alpha-(125)latrocrustotoxin with nerve cell membranes from the river crab astacus astacus].alpha-latrocrustatoxin, the crustacean-specific neurotoxin from the venom of the black widow spider latrodectus mactans tredecimguttatus was radioactively labelled with bolton-hunter reagent to the specific activity of 160 ci/mmol with retention of the biological activity. a highly specific binding of radioactive toxin on plasmatic membranes from the crayfish astacus astacus nerve cells with bmax = 0.04 pmol binding toxin/mg membrane protein and kd = 0.7 x 10(-10) m was demonstrated.19911768295
biochemical and histochemical observations on effects of low-level heavy metal load (lead, cadmium) in different organ systems of the freshwater crayfish, astacus astacus l. (crustacea: decapoda).the effects of low-level lead (20 micrograms/liter) and/or cadmium (2 micrograms/liter) exposure on the structure and function of different organ systems of the freshwater crayfish. astacus astacus l. (crustacea: decapoda) were estimated by several biochemical and histochemical methods. the animals were incubated during 10 weeks (max.) at a temperature of 10 degrees c and a normal diurnal rhythm. lead accumulated in high amounts especially in the digestive gland, carapax, and gills, whereas the ...19912065627
kinetics of nitroanilide cleavage by astacin.the investigation of the catalytic properties of astacin, a zinc-endopeptidase from the crayfish astacus astacus l., has gained importance, because the enzyme represents a novel, structurally distinct family of metalloproteinases which also includes a human bone morphogenetic protein (bmp1). astacin releases nitroaniline from succinyl-alanyl-alanyl-alanyl-4-nitroanilide (suc-ala-ala-ala-pna), a substrate originally designed for pancreatic elastase. this activity was unexpected since only few met ...19911910577
alpha2-macroglobulin from hemolymph of the freshwater crayfish astacus astacus.1. a high mol. wt proteinase inhibitor has been purified from the haemolymph of the freshwater crayfish astacus astacus. 2. the protein is a disulphide-bonded dimer (mr 390,000) of two identical polypeptide chains (mr 185,000). 3. the inhibitor displays a broad specificity and protects trypsin from inhibition by soybean trypsin inhibitor and thus is similar to vertebrate alpha 2-macroglobulin. 4. the alpha 2-macroglobulin-like inhibitor from astacus interacts with bovine trypsin in an equimolar ...19911714366
hemocyanins in spiders, xxiii. complete amino-acid sequence of subunit a of eurypelma californicum hemocyanin.the complete amino-acid sequence of subunit a of the hemocyanin of the tarantula eurypelma californicum was determined by manual sequencing. by limited chymotrypsinolysis, subunit a is split into two fragments of 25 kda and 40 kda, respectively, only one single peptide bond being attacked. the whole chain contains 15 methionine residues, after cyanogen bromide cleavage, 15 peptides were identified indicating that one residue (met85) was not split by the cyanogen bromide reaction. for subcleavage ...19902222854
quantal secretion and loss of vesicles induced by veratridine at the crayfish neuromuscular junction.experiments were conducted in nerve-muscle preparations of small young crayfish (austropotamobius torrentium, astacus astacus). application of veratridine in the superfusate induced strong quantal release of transmitter. after about 5 min when quantal release had declined to a low level preparations were fixed for electron microscopy. unlike control preparations, veratridine-treated preparations revealed nerve terminals which were largely depleted of their synaptic vesicles. our findings suggest ...19901977109
viscoelastic properties of the slowly adapting stretch receptor muscle of the crayfish.the viscoelastic properties of the muscle associated with the slowly adapting stretch receptor organ of the crayfish (astacus astacus) were studied by recording the tension response to various length changes. when steady-state length changes were applied to the muscle, the tension developed in a non-linear way, increasing slowly for small extensions and rapidly when extension increased. muscle tension responses to ramp-and-hold extensions were characterized by a transient peak followed by a grad ...19902239352
voltage dependence of depolarization-contraction coupling processes in skeletal muscle cells.changes of contraction and optical anisotropy of isolated skeletal muscle cells from rana temporaria and astacus fluviatilis were compared under voltage clamp conditions. the time course of the optical signal from frog muscle was shown to consist of two components which could be attributed to calcium binding both on the sarcoplasmic reticulum ca-atpase and troponin c. the optical signal from the crayfish muscle has no distinguishable components, and its onset probably reflects the start of ca-at ...19902358185
biosynthesis of astacus protease, a digestive enzyme from crayfish.for the first time, the site of biosynthesis of a well characterized invertebrate digestive enzyme is localized. the enzyme chosen, astacus protease, is a zinc-metalloenzyme occuring in high concentration in the gastric fluid of the freshwater crayfish astacus astacus. enzyme production was stimulated in adult crayfish either by feeding or by removal of the gastric fluid. immunohistochemistry, cytology and investigation with radioactive tracers demonstrate that in the hours following stimulation ...19892656593
[3h-thymidine and 3h-uridine incorporation into the heart cells of the freshwater crayfish astacus astacus and the swimming crab portunus holsatus].dna and rna syntheses in the heart cells of two decapod species were investigated with the aid of electron microscopic autoradiography. isotopes were injected in the cavity of adult animals 4 hours before fixation. 3h-thymidine labeling was found in several satellite cell nuclei and in some particular epicardial cell nuclei. none of myonuclei was labeled. 3h-uridine incorporated in all the nuclei of muscle fibers. satellite cells were labeled with 3h-uridine very slightly, if at all. such a pecu ...19882469240
electrophysiological evidence for ammonium as a substitute for potassium in activating the sodium pump in a crayfish sensory neuron.electrophysiological studies were performed on slowly adapting cells of the crayfish (astacus astacus) stretch receptor to examine some aspects of the operation of the sodium pump. intracellular sodium activity (aina) and ph (phi) were measured with liquid ion exchanger microelectrodes and the effects of nh3/nh+4 were observed. in cells in which the sodium pump was inhibited by k+-free solution, nh+4 induced a decrease of aina that can be explained only in na+ extrusion is assumed. phi measureme ...19873567730
induction of cytochrome p-450 mediated mono-oxygenase reactions and conjugation activities in freshwater crayfish (astacus astacus).the inducibility of the freshwater crayfish (astacus astacus) biotransformation enzymes with model inducers (aroclor 1254, beta-naphthoflavone, phenobarbital) were investigated three days after intra cephalothoracic injection in the fasting crayfish at 5 degrees c. of the monooxygenase activities, 7-ethoxycoumar in o-deethylase increased in the hepatopancreas significantly (p less than 0.05) after beta-naphthoflavone administration. benzo(a)pyrene hydroxylase did not change. aroclor 1254 and phe ...19863468918
effects of halothane on the transducer and potential activated currents of the crustacean stretch receptor.halothane was applied to the stretch receptor neuron of the crayfish (astacus astacus) and the effects on the transducer properties and the potential activated currents were studied with potential clamp technique using two microelectrodes. exposure to halothane reduced the frequency of action potentials during stretch. this was shown to be due to effects both on the action potential generating currents and the transducer current. halothane partially blocked the ttx sensitive fast inward current ...19853002128
the cytotoxic reaction of hemocytes from the freshwater crayfish, astacus astacus.crayfish hemocytes displayed cytotoxic capacity towards all tested mammalian tumor and nontumor cell lines. the ratio required for the cytotoxic action of effector cells to target cells was at least 1:1. the lysis of the target cells required a minimum of 1 hr to become detected. after separation and isolation of the hemocyte populations of crayfish, the semigranular and granular cells retained their cytotoxic capacity. these cells contain the prophenoloxidase activating (propo) system, a comple ...19854028165
hemocyanins in spiders, xix. complete amino-acid sequence of subunit d from eurypelma californicum hemocyanin, and comparison to chain e.the complete primary structure of subunit d of the hemocyanin from the tarantula eurypelma californicum was determined by manual micro sequencing. subunit d of mr = 73000 is split about in the middle of the chain during limited trypsinolysis, only one single bond being attacked. the whole chain contains 14 methionine residues and after cyanogen bromide cleavage 15 peptides could be isolated by gel and ion exchange chromatography and high pressure liquid chromatography. the cyanogen bromide pepti ...19836642428
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