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[sphaerospora truttae (myxosporidia) in salmo trutta and thymallus thymallus: first detection in thüringia and in the hartz region and also in the grayling].s. truttae is described from brown trout and grayling in middle germany. this species is obviously not connected with pkx, the causative agent of proliferative kidney disease (pkd) in salmonids. s. truttae, however, is important in this connection from the viewpoint of differential diagnostics.19911888073
mitochondrial dna variation of gyrodactylus spp (monogenea, gyrodactylidae) populations infecting atlantic salmon, grayling, and rainbow trout in norway and sweden.approximately 800 bp of the mitochondrial cytochrome oxidase i (coi) gene were sequenced from 76 gyrodactylus specimens of 32 salmonid host populations, i.e. from salmo salar, thymallus thymallus, and oncorhynchus mykiss in norway, sweden and latvia. the coi sequences indicated a substantial intraspecific differentiation of gyrodactylus salaris and gyrodactylus thymalli. in total, 12 haplotypes were identified which group into five well supported clades, three clades with parasites from atlantic ...200314572510
pituitary adenylate cyclase-activating polypeptide and growth hormone-releasing hormone-like peptide in sturgeon, whitefish, grayling, flounder and halibut: cdna sequence, exon skipping and evolution.to better understand the evolution of pituitary adenylate cyclase-activating polypeptide (pacap) and growth hormone-releasing hormone (ghrh), we isolated the cdnas encoding these peptides from the brains of five species of fish: sturgeon, whitefish, grayling, flounder and halibut. both hormones are encoded in tandem in full-length cdnas. we compared the phylogenetic relationship among these and other known sequences encoding pacap. in closely related species, transcripts encoding pacap and ghrh ...200212409211
the use of host specificity, pathogenicity, and molecular markers to differentiate between gyrodactylus salaris malmberg, 1957 and g. thymalli zitnan, 1960 (monogenea: gyrodactylidae).the validity of gyrodactylus thymalli has been questioned, based on its morphological and genetic resemblance to g. salaris. this taxonomic problem has practical implications regarding correct diagnosis of g. salaris, which has proved to be highly pathogenic to stocks of wild norwegian atlantic salmon. the host specificity and pathogenicity of g. salaris and g. thymalli were experimentally tested on salmon and grayling. both parasite species were able to infect, live and reproduce on both fish s ...200211860035
the susceptibility of grayling (thymallus thymallus) to experimental infections with the monogenean gyrodactylus salaris.the pathogenic monogenean gyrodactylus salaris infecting atlantic salmon (salmo salar) is found to attach and reproduce under laboratory conditions on several species in the subfamily salmoninae other than the atlantic salmon. the gyrodactylid species gyrodactylus thymalli infecting grayling (thymallus thymallus) in another subfamily, thymallinae, is previously said to be very similar to g. salaris based on morphometry and genetical analysis which prompted the present laboratory experiments to t ...200111403770
fish status survey of nordic lakes: effects of acidification, eutrophication and stocking activity on present fish species composition.the status of fish populations in 3821 lakes in norway, sweden and finland was assessed in 1995-1997. the survey lakes were chosen by stratified random sampling from all (126 482) fennoscandian lakes > or = 0.04 km2. the water chemistry of the lakes was analyzed and information on fish status was obtained by a postal inquiry. fish population losses were most frequent in the most highly acidified region of southern norway and least common in eastern fennoscandia. according to the inquiry results, ...200312733793
non-repetitive dna sequence divergence in phylogenetically diploid and tetraploid teleostean species of the family cyprinidae and the order isospondyli.non-repetitive dna of anciently tetraploid teleostean species was analysed for the presence of duplicated sequences. closely related diploid species were investigated in comparison. from the reassociation kinetics of total nuclear dna, rate constants and fraction sizes of classes of repetitive and non-repetitive sequences were determined. dna fractions enriched in the slowest renaturing sequence class were determined. dna fractions enriched in the slowest renaturing sequence class were prepared ...1979533669
analysis of ribosomal rna intergenic spacer (igs) sequences in species and populations of gyrodactylus (platyhelminthes: monogenea) from salmonid fish in northern europe.the intergenic spacer (igs) region of ribosomal rna genes was amplified and sequenced from a variety of gyrodactylus specimens collected from wild and farmed atlantic salmon salmo salar, rainbow trout oncorhynchus mykiss, and grayling thymallus thymallus, from various locations in northern europe. phylogenetic analysis of the sequences confirmed the distinction between g. salaris malmberg, 1957 and g. thymalli zitnan, 1960, supporting their validity as separate species. g. salaris adapted to rai ...200314960037
emerging vesiculo-type virus infections of freshwater fishes in europe.rhabdoviruses were isolated from perch perca fluviatilis and largemouth bass micropterus salmoides exhibiting clinical signs of disease. preliminary studies indicated that these viruses could be neutralised by antisera to perch rhabdovirus (dorson et al. 1984) and may be similar to those previously isolated from grayling thymallus thymallus and pike-perch stizostedion stizostedion. the relationship between these viruses and the previously characterised fish rhabdoviruses, pike fry rhabdovirus (p ...200314960032
identification of reproductively isolated lineages of amur grayling (thymallus grubii dybowski 1869): concordance between phenotypic and genetic variation.we analysed variation at maternally (mitochondrial dna control region sequences) and bi-parentally (10 microsatellites) inherited genetic markers, as well as across 12 meristic characters in 7 populations of amur grayling, thymallus grubii, from eastern siberia. all three data sets were concordant in supporting the existence of three diagnosable, reciprocally monophyletic, and most probably reproductively isolated, lineages of grayling within the amur drainage. there was a significant correlatio ...200312919473
evidence of enhanced bacterial invasion during diplostomum spathaceum infection in european grayling, thymallus thymallus (l.).farmed grayling, thymallus thymallus (l.), are susceptible to atypical aeromonas salmonicida (aas) infections. interactions between bacteria and parasites were studied using grayling subjected to concomitant exposure to aas bacteria and the digenean parasite diplostomum spathaceum. atypical as was detected from fish by a combination of bacterial cultivation and polymerase chain reaction techniques. a detection level of 17 aas cells per 100 mg intestine tissue sample was obtained. concomitant bac ...200616436118
[the oxygen diffusion coefficient in isolated skeletal muscle fibers].the oxygen diffusion coefficients in isolated skeletal muscle fibres of baikal seal and grayling, white rat, chicken were calculated on the basis of experimentally determined curve of dependence of the o2 consumption on po2 and the radius of the fibres. in all the cases, the diffusion coefficient was smaller in the fibres than in water. the oxygen diffusion coefficient was increased during embryogenesis and postnatal period in chicken. the influence of different parameters of the oxygen transpor ...19911668155
systemic spironucleosis in sea-farmed atlantic salmon salmo salar, caused by spironucleus barkhanus transmitted from feral arctic char salvelinus alpinus?a hexamitid flagellate was found in the gall bladder and intestine of arctic char salvelinus alpinus in northern norway. scanning and transmission electron microscopy showed this flagellate to be identical to spironucleus barkhanus from grayling thymallus thymallus and farmed atlantic salmon salmo salar. it is hypothesized that systemic spironucleosis in sea-caged atlantic salmon was due to transmission of flagellates from feral char to the salmon.19989653460
in vitro cultivation and temperature-dependent growth of two strains of spironucleus barkhanus (diplomonadida: hexamitidae) from atlantic salmon salmo salar and grayling thymallus thymallus.spironucleus barkhanus from muscle abscesses of farmed atlantic salmon salmo salar l., and from the gall bladder of grayling thymallus thymallus (l.) was cultivated axenically in a medium routinely used for cultivation of the human pathogen giardia duodenalis. trophozoites multiplied by binary division, but multinucleated cells (< 10 nuclei) were frequently observed. complete cell divisions were never observed in these cells. both strains grew at all temperatures tested (5, 10, 15 and 20 degrees ...19989653459
liver function abnormalities in the course of a type a (h1n1) influenza outbreak: relation to reye's syndrome.in the course of the a/brazil (h1n1) outbreak of 1978-1979, two cases of reye's syndrome occurred in grayling, michigan, an area with a county-wide population of 2056 school age children. school absenteeism peaked at levels between 16-28 per cent. clinical histories and paired blood specimens were collected from 860 school children; the initial blood was obtained shortly after the peak of the outbreak. serologic results confirmed that type a h1n1 virus was the cause of the outbreak. serum alanin ...19817304602
spatial and population genetic structure of microsatellites in white pine.we evaluated the population genetic structure of seven microsatellite loci for old growth and second growth populations of eastern white pine (pinus strobus). from each population, located within hartwick pines state park, grayling, michigan, usa, 120-122 contiguous trees were sampled for genetic analysis. within each population, genetic diversity was high and inbreeding low. when comparing these populations, there is a significant, but small (less than 1%), genetic divergence between population ...200415487991
effects of chemical pollution on the activities of hepatic xenobiotic metabolizing enzymes in fish from the river rhône.polychlorobiphenyl (pcbs) levels and hepatic xenobiotic metabolizing enzyme activities were measured in fish from three locations of the river rhône to study the consequences of a constant loading of pcbs from a pcb incineration plant. our results show that levels of pcbs and enzyme activities were higher in fish living downstream from the plant than in fish from two locations upstream, suggesting enzyme induction by pcbs (known to be potent inducers in laboratory conditions). enzyme activities ...19883145559
initial steps of speciation by geographic isolation and host switch in salmonid pathogen gyrodactylus salaris (monogenea: gyrodactylidae).to test the hypothesis that host-switching can be an important step in the speciation of gyrodactylid monogenean flatworms, we inferred the phylogeny within a cluster of parasites morphologically close to gyrodactylus salaris malmberg 1957, collected from atlantic, baltic and white sea salmon (salmo salar), farmed rainbow trout (oncorhynchus mykiss), and grayling (thymallus thymallus) from northern europe. the internal transcribed spacer region of the nuclear ribosomal gene was sequenced for tax ...200415013741
the parasite fauna of brown trout salmo trutta, white fish coregonus lavaretus, and grayling thymallus thymallus from water bodies of north karelia (russia).the data on parasite fauna of brown trout salmo trutta, whitefish coregonus lavaretus, and grayling thymallus thymallus from lake-river system paanajarvi-olanga (white sea basin) are presented. as lake-river systems on this area remain in natural conditions, without any anthropogenic pressure, the parasite fauna of salmonidae in these water bodies had not been changed and has an archetypal status.200416865973
[phylogenetic analyses of the family tetraonchidae (platyhelminthes: monogenea)].a phylogenetic reconstruction of the monogenean family tetraonchidae was carried out by methods of parsimony-based cladistics. the analysis included 20 species of tetraonchids and two out-groups (sundanonchus tomanorum and dactylogyrus amphibothrium) and was based on 34 morphofunctional characters. software paup 4.0 and winclada were used for the phylogenetic reconstructions. obtained results allow proposing a preliminary phylogenetic hypothesis of the family tetraonchidae along with the discuss ...200415553772
the incongruence of nuclear and mitochondrial dna variation supports conspecificity of the monogenean parasites gyrodactylus salaris and g. thymalli.the monogenean gyrodactylus salaris malmberg, 1957 is an economically important parasite on atlantic salmon whereas the morphologically very similar g. thymalli zitnan, 1960 on grayling is considered harmless. even molecular markers cannot unambiguously discriminate both species. the nuclear internal transcribed spacer (its) sequences are identical in both species, and although mitochondrial cytochrome oxidase i (coi) sequences show substantial variation, no support for monophyly of either speci ...200616863602
algorithms for selecting informative marker panels for population assignment.given a set of potential source populations, genotypes of an individual of unknown origin at a collection of markers can be used to predict the correct source population of the individual. for improved efficiency, informative markers can be chosen from a larger set of markers to maximize the accuracy of this prediction. however, selecting the loci that are individually most informative does not necessarily produce the optimal panel. here, using genotypes from eight species--carp, cat, chicken, d ...200516305328
toxicity of acid aluminium-rich water to seven freshwater fish species: a comparative laboratory study.the present study focuses on the relative sensitivity among freshwater fish species to aqueous aluminium. seven common scandinavian fish species were exposed to acidic al-rich water, acidic al-poor water, and approximately neutral water as a control. the relative sensitivity among the species to an acute aluminium challenge was documented, and was in the following order: atlantic salmon, salmo salar, as the most sensitive; then roach, rutilus rutilus; minnow, phoxinus phoxinus; perch, perca fluv ...199715093412
comparison of mercury and methylmercury in northern pike and arctic grayling from western alaska rivers.in western alaska, mercury (hg) could be a potential health risk to people whose diet is primarily fish-based. in 2000, total hg (thg) and methylmercury (mehg) were examined in northern pike (esox lucius) and arctic grayling (thymallus arcticus) from two watersheds in western alaska, the yukon and kuskokwim rivers. whitefish (coregonus sp.) were also examined from the kuskokwim river. pike from the yukon and kuskokwim rivers had mean concentrations of thg in muscle of 1.506 and 0.628 mg/kg wet w ...200312656259
occurrence of the microsporidian parasite nucleospora salmonis in four species of salmonids from the massif central of france.nucleospora salmonis (hedrick, groff et baxa, 1991), an intranuclear microsporidian parasite of marine and freshwater fish, causes diseases mainly in salmonid species. losses have been reported in stocks of salmonid fish reared in the region of auvergne (france). the cause of chronic mortalities in the local host species raised in aquaculture and destined for supplementation of the river system loire-allier was examined. the presence of n. salmonis was confirmed by pcr and histology in salmo sal ...200616696429
epidemiology of gyrodactylus salaris (monogenea) in the river tornionjoki, a baltic wild salmon river.the occurrence of gyrodactylus salaris in the river tornionjoki was investigated in 2000-2004. infection of salmon parr, salmo salar, was common in the uppermost reach of the river system but decreased downstream and was rare in the lowermost reach. this pattern was consistent across the study period regardless of varying water temperatures. the oldest age groups of parr were more often infected than younger ones throughout the river system, irrespective of their origin (wild or stocked). parasi ...200818355178
complex patterns of colonization and refugia revealed for european grayling thymallus thymallus, based on complete sequencing of the mitochondrial dna control region.the complete mitochondrial dna (mtdna) control region (1043 base pairs) and 162-bp of flanking transfer rna genes were sequenced in 316 european grayling, thymallus thymallus, from 44 populations throughout the western european range of the species. a total of 58 haplotypes were revealed with pairwise divergence ranging from 0.001 to 0.038. an inferred intraspecific phylogenetic tree revealed two well-supported clades within the danube basin, one highly divergent clade in the adriatic basin, and ...200212144660
host specificity dynamics: observations on gyrodactylid monogeneans.the directly transmitted viviparous gyrodactylids have high species richness but low morphological and biological diversity, and many species are recorded from only a single host. they therefore constitute a guild of species ideal for studies of the evolutionary significance of host specificity. the group has the widest host range of any monogenean family, being found on 19 orders of bony fish. however, individual species range from narrowly specific (71% of 402 described species recorded from a ...200211835970
putative virulence factors of atypical aeromonas salmonicida isolated from arctic charr, salvelinus alpinus (l.), and european grayling, thymallus thymallus (l.).atypical aeromonas salmonicida (aas) causes generalized lethal infections in farmed arctic charr, salvelinus alpinus (l.), and european grayling, thymallus thymallus (l.), and is thus a serious threat for culture of these fish species. virulence factors were studied among isolates of aas from arctic charr (n = 20), european grayling (n = 19) and other fish species (n = 20), of which 48 were of finnish and 11 of swedish origin. all isolates produced an a-layer. extracellular products (ecp) of the ...200312899410
genetic diversity of atypical aeromonas salmonicida studied by pulsed-field gel electrophoresis.pulsed-field gel electrophoresis (pfge) pattern analysis with xbai restriction enzyme was used to study the genetic heterogeneity of 88 atypical aeromonas salmonicida strains which were earlier or during this study characterized phenotypically, by ribotyping (clai/psti) and by plasmid profile analysis. the strains of certain'ribotypes were also analysed by digestion with spei. the strains represented different geographic locations: finland (72 strains), iceland (5 strains), norway (5 strains), s ...199910579451
ecotoxicological assessment of sediment, suspended matter and water samples in the upper danube river. a pilot study in search for the causes for the decline of fish catches.goals, scope and background: fish populations, especially those of the grayling (thymallus thymallus), have declined over the last two decades in the upper danube river between sigmaringen and ulm, despite intensive and continuous stocking and improvement of water quality since the 1970s. similar problems have been reported for other rivers, e.g. in switzerland, great britain, the united states and canada. in order to assess if ecotoxicological effects might be related to the decline in fish cat ...200617067025
the marine pathogenic genotype of spironucleus barkhanus from farmed salmonids redescribed as spironucleus salmonicida n. sp.there are two genotypes of the diplomonad spironucleus barkhanus. based on sequence data from the small subunit ribosomal rna gene the conspecificity of these two genotypes has been questioned. therefore, we have sampled spironucleus from 27 fish, representing 14 populations, five species, and four genera. partial nucleotide sequences from the three genes; small subunit ribosomal dna, glutamate dehydrogenase 1 and alpha-tubulin were compared. the pathogenic isolates of s. barkhanus, which causes ...200617123418
permanent impairment in the feeding behavior of grayling (thymallus thymallus) exposed to methylmercury during embryogenesis.embryos of grayling (thymallus thymallus) were exposed to different concentrations of methylmercury (0.16, 0.8, 4.0 and 20 micrograms hg l-1) during the first 10 days of development. the exposure resulted in body concentrations in the newly hatched fry of 0.09, 0.27, 0.63 and 3.80 micrograms hg g-1 wet wt., respectively. a control group had a body concentration of 0.01 microgram hg g-1. morphological disturbances were only found in the highest exposure group. three years later, at a size of 13.8 ...19989652130
amplification of distinct subfamilies of short interspersed elements during evolution of the salmonidae.there are at least three different kinds of short interspersed repetitive elements in salmonid genomes. of these, members of the hpai family are found to be most widely distributed in salmonid species. the hpai family is present with high copy numbers in all members of the subfamily salmoninae, such as salmon, trout and charr. in order to determine whether the amplification of the hpa sequence occurred rapidly within a short evolutionary period or gradually, over the long term, a search was made ...19948071990
[geographical variation of allele frequencies at the ldh-a* locus in the arctic grayling thymallus arcticus pall. and in the european grayling thymallus arcticus l].the allele frequencies of ldh-a* locus were studied in the population of siberian grayling from the kozhym river (pechora basin) and in the population of european grayling from pechora, mezen', and vym' rivers (northern dvina basin). in samples of both species (n = 134), three ldh-a phenotypes have been identified in total, which proved to be under the control of two alleles: ldh-a*100 and ldh-a*50. the alternative alleles of ldh-a* locus were identified in the populations of siberian grayling f ...200415575515
a comparative immunopathological study of injection site reactions in salmonids following intraperitoneal injection with oil-adjuvanted vaccines.an adequate understanding of the inflammatory mechanisms following intraperitoneally-injected oil-adjuvanted vaccines in fish is required for the improvement of the quality of vaccines. we report the findings of a study in which the importance of neutrophils, macrophages, lymphocytes and mast cells (mcs) in early inflammatory reactions of atlantic salmon were examined in comparison with those of rainbow trout and grayling. the inflamed areas in the pylorus/pancreas area (injection site) were seq ...200616221512
toxicity of a phytosterol mixture to grayling (thymallus thymallus) during early developmental stages.the study concerns the toxicity of a phytosterol mixture, ultrasitosterol, consisting mainly of beta-sitosterol 75.7% and beta-sitostanol 13.0%, to grayling (thymallus thymallus) embryos. eyed eggs were exposed to three concentrations (1 microg/l, 10 microg/l, and 50 microg/l) of ultrasitosterol for 4 weeks. embryos and later on hatched fry were taken for triiodothyronine (t3), thyroxine (t4), and histopathological analyses after 7, 14, 21, and 28 days of exposure. most of the eggs (>95%) hatche ...200515886854
comparison of seasonal dynamics of the essential pufa contents in benthic invertebrates and grayling thymallus arcticus in the yenisei river.seasonal dynamics of contents of essential polyunsaturated fatty acids (pufa) in dominant groups of benthic invertebrates: gammarids (gammaridae, amphipoda), oligochaetes (oligochaeta), chironomid larvae (chironomidae, diptera) and caddisfly larvae (trichoptera), and dominant benthivorous fish, siberian grayling thymallus arcticus, have been studied in ecosystem of the large siberian river. during the year of the study most benthic invertebrate taxa showed significant variations in the contents ...200616996285
experience from lipizzan horse and salmonid species endemic to the adriatic river system. examples for the application of molecular markers for preservation of biodiversity and management of animal genetic resources.management of breeding- and free-living populations, traditionally based on phenotypic traits, relays more and more on availability of reliable information about the basic population genetic parameters as heterozygosity, mean number of alleles per locus, percentage of polymorphic loci, population structuring, genetic distances and others. therefore, the application of molecular markers, revealing a great deal of phenotypically hidden information, becomes inevitable for population analysis. conse ...200415380646
assessing the impact of a downscaled climate change simulation on the fish fauna in an inner-alpine river.this study assesses the impact of a changing climate on fish fauna by comparing the past mean state of fish assemblage to a possible future mean state. it is based on (1) local scale observations along an inner-alpine river called mur, (2) an ipcc emission scenario (is92a), implemented by atmosphere-ocean global circulation model (aogcm) echam4/opyc3, and (3) a model-chain that links climate research to hydrobiology. the mur river is still in a near-natural condition and water temperature in sum ...200717587065
lack of circadian regulation of in vitro melatonin release from the pineal organ of salmonid teleosts.in many teleost species, the photoreceptive pineal organ harbors the circadian clock that regulates melatonin release in the pineal organ itself. however, the pineal organ of three salmonids (rainbow trout oncorhynchus mykiss, masu salmon oncorhynchus masou, and sockeye salmon oncorhynchus nerka) did not exhibit circadian rhythms in melatonin release when maintained under constant darkness (dd) in vitro, suggesting that the pineal organs of all salmonids lack the circadian regulation of melatoni ...200717681505
[component communities of parasites in the grayling thymallus thymallus (l.) (salmoniformes, thymallidae) and the minnow phoxinus phoxinus (l.) (cypriniformes, cyprinidae) from the pechora river].component communities of parasites of thymallus thymallus and phoxinus phoxinus are described. the communities differ in the number of species and in the number of dominate species, which is one in p. phoxinus and usually two in t. thymallus. in the first case the dominate species is allogenic, while in the second case dominate species are autogenic. values of the species diversity indexes are also different for these communities. the differences between parasite communities of t. thymallus and ...200718052005
cumulative industrial activity alters lotic fish assemblages in two boreal forest watersheds of alberta, canada.we evaluated the cumulative effects of land use disturbance resulting from forest harvesting, and exploration and extraction of oil and gas resources on the occurrence and structure of stream fish assemblages in the kakwa and simonette watersheds in alberta, canada. logistic regression models showed that the occurrence of numerically dominant species in both watersheds was related to two metrics defining industrial activity (i.e., percent disturbance and road density), in addition to stream wett ...200818815827
fate of chlorinated fatty acids in migrating sockeye salmon and their transfer to arctic grayling.to investigate whether biotransport constitutes an entry route into pristine ecosystems for nonpersistent, nonvolatile xenobiotic compounds, extractable organically bound halogen in sockeye salmon (oncorhynchus nerka) from alaska was determined before and after spawning migration. the major organohalogen compounds in the salmon were halogenated fatty acids, predominantly chlorinated species that accounted for up to 35% of the extractable, organically bound chlorine (eocl) in the fish tissues. th ...200415575271
a salmonid est genomic study: genes, duplications, phylogeny and microarrays.salmonids are of interest because of their relatively recent genome duplication, and their extensive use in wild fisheries and aquaculture. a comprehensive gene list and a comparison of genes in some of the different species provide valuable genomic information for one of the most widely studied groups of fish.200819014685
[structure of component parasite communities in the grayling, thymallus thymallus l. (salmoniformes, thymallidae), and minnow, phoxinus phoxinus l. (cypriniformes, cyprinidae), from the upper reaches of the pechora river].a comparative analysis of parasite communities in the grayling and minnow has been performed. these communities differ in the number of constituent species and in that the community of the minnow is dominated by one allogenic species, whereas that of the grayling usually has two dominants, both being autogenic species. the values of species diversity indices characterizing these communities are also different. differences between the parasite communities of these fish species reflect the positio ...200919548620
characterisation of atypical aeromonas salmonicida infection in arctic charr salvelinus alpinus and european grayling thymallus thymallus.cultured stocks of arctic charr salvelinus alpinus and european grayling thymallus thymallus are vulnerable to infection by achromogenic atypical aeromonas salmonicida (aas). in finland, natural stocks of both fish species have to be supported by restocking, and aas infection poses a threat to successful restocking because no preventive means are available. in this study, we analysed aas isolates from arctic charr and european grayling and from other sources genetically, and characterised the si ...200516231637
[parasite fauna in salmonidean fishes from the paanaiarvi-olanga lake-river system].the data on parasite fauna in the brown trout salmo trutta, white fish coregonus lavaretus, and grayling thymall thymallus from the paanajarvi-olanga lake-river system (white sea basin) are presented. as like-river systems in this area remain in natural conditions, without any anthropogenic pressure, the parasite fauna in salmonoideans from these water bodies had not been changed and has an archetypical state. the parasite fauna core is established in fishes aged 3+. parasite species forming the ...200515810556
[cytochemical characteristics of the myxosporidian henneguya cerebralis (myxosporidia, myxobolidae) and pathohistological changes in the kosogol grayling in myxosporidiasis].content and distribution of rna, protein, dna, glycogen and carbohydrate components in spores and vegetative sporeforming stages plasmodium of henneguya cerebralis were described. pathohistological changes in head tissus of thymallus arcticus nigrescens are discussed. the conclusion on the relative youth of parasite system "h. cerebralis--thymallus arcticus nigrescens" is made.19854011305
host-based identification is not supported by morphometrics in natural populations of gyrodactylus salaris and g. thymalli (platyhelminthes, monogenea).gyrodactylus salaris is a serious pest of wild pre-smolt atlantic salmon (salmo salar) in norway. the closely related g. thymalli, originally described from grayling (thymallus thymallus), is assumed harmless to both grayling and salmon. the 2 species are difficult to distinguish using traditional, morphometric methods or molecular approaches. the aim of this study was to explore whether there is a consistent pattern of morphometrical variation between g. salaris and g. thymalli and to analyse t ...200717697446
[molecular-genetic detection of a nonpathogenic genotype of spironucleus barkhanus (diplomonadida: hexamitidae) in the black baikal grayling (thymallus arcticus baicalensis dybowski, 1874)].a nonpathogenic genotype of spironucleus barkhanus (diplomonadida: hexamitidae) has been revealed for the first time in the baikal grayling (salmoniformes: thymallidae) by molecular-genetic methods. sequences corresponding to a fragment of the gene encoding the small ribosomal subunit rna (ssu rrna) have been obtained. the genotype of s. barkhanus from baikal fish is identical to that characteristic of the parasite found in freshwater salmonid fishes.200818946998
the salmonid cathelicidins: a gene family with highly varied c-terminal antimicrobial domains.the cathelicidin family of host defence peptides is regarded as an important component of the host innate immune system. its members have been found in mammals, birds, primitive vertebrate atlantic hagfish and, most recently, also in ray-finned fish such as rainbow trout and atlantic salmon. by using genomic pcr amplifications and rt-pcr tissue analyses we have here investigated and characterized the cathelicidin gene family in three salmonids: brown trout (salmo trutta fario), brook trout (salv ...200919168146
mitochondrial dna variation of a natural population of gyrodactylus thymalli (monogenea) from the type locality river hnilec, slovakia.the monogenean flatworm gyrodactylus thymalli (zitnan, helminthologia, 2:266-269, 1960) is considered a harmless ectoparasite on grayling (thymallus thymallus). the species is closely related to g. salaris malmberg, 1957 that causes severe gyrodactylosis on atlantic salmon (salmo salar) in many norwegian rivers. in this paper, we study the mitochondrial diversity of a g. thymalli population from one of the type localities hrable on river hnilec, slovakia. by sequencing parts of the mitochondrial ...200717694404
the complete mitochondrial dna sequence of the monogenean gyrodactylus thymalli (platyhelminthes: monogenea), a parasite of grayling (thymallus thymallus).we present the complete mitochondrial (mt) genome of gyrodactylus thymalli, a monogenean ectoparasite on grayling (thymallus thymallus). the circular genome is 14788 bp in size and includes all 35 genes recognized from other flatworm mt genomes. the overall a+t content of the mt genome is 62.8%. twenty regions of non-coding dna ranging from 1 to 111 bp in length were identified in addition to 2 highly conserved large non-coding regions 799 bp and 767 bp in size. compared to the recently describe ...200717559954
transmission of tetracapsuloides bryosalmonae (myxozoa: malacosporea) to fredericella sultana (bryozoa: phylactolaemata) by various fish species.tetracapsuloides bryosalmonae is a myxozoan parasite of salmonids and freshwater bryozoans, which causes proliferative kidney disease (pkd) in the fish host. to test which fish species are able to transmit t. bryosalmonae to bryozoans, an infection experiment was conducted with 5 pkd-sensitive fish species from different genera. rainbow trout oncorhynchus mykiss, brown trout salmo trutta, brook trout salvelinus fontinalis, grayling thymallus thymallus and northern pike esox lucius were cohabitat ...200818500029
an investigation into the prevalence of renibacterium salmoninarum in farmed rainbow trout, oncorhynchus mykiss (walbaum), and wild fish populations in selected river catchments in england and wales between 1998 and 2000.a cross-sectional survey of renibacterium salmoninarum infection in farmed rainbow trout (rbt) and wild fish populations was carried out in 10 farms and six river catchments, respectively, in england and wales. the majority of the wild fish were sampled in 1998 and the farmed fish in 2000. grayling, thymallus thymallus, and brown trout, salmo trutta, were the main wild species sampled. two fish, one grayling and one salmon, salmo salar, were r. salmoninarum culture-positive, compared with 40 con ...200818234016
bioaccumulation of metals in fish of salmonidae family and the impact on fish meat quality.the study was aimed at determining the levels of metals in water samples and muscles of the fish caught in the una river basin, located in the northwestern part of bosnia and herzegovina. for that purpose, three fish species: brown trout (salmo trutta m. fario), grayling (thymallus thymallus) and californian trout (salmo gairdneri), together with stem water samples, were analyzed for metal concentrations (pb, hg, cd, as, mn, ni, cu, cr, se, co, sn, zn, fe, ca, p) during a 2-year period. the fish ...200717171264
first isolation of hirame rhabdovirus from freshwater fish in europe.a rhabdovirus was isolated in cell culture inoculated with tissue material from diseased grayling, thymallus thymallus (l.), originating from a fish farm affected by a mortality episode in poland. diagnostics tests showed that the virus was not related to novirhabdoviruses known in europe, nor to vesiculovirus-like species, except perch rhabdovirus (prhv) with which it shared moderate serological relations. however, rt-pcr with prhv probes gave negative results. to identify the virus, a random-p ...201423962315
molecular and karyological identification and morphological description of cystocercous cercariae of phyllodistomum umblae and phyllodistomum folium (digenea, gorgoderidae) developing in european sphaeriid bivalves.two cystocercous gorgoderid cercariae of the genus phyllodistomum braun, 1899, phyllodistomum umblae (fabricius, 1780) and phyllodistomum folium (olfers, 1816), developing in sphaeriid bivalves from norway and lithuania, were studied and compared. our previous molecular studies revealed very close phylogenetic relation of these two species and proved that cystocercous cercariae of p. folium develop in sporocysts in the gills of sphaeriid bivalves. in the present study morphological descriptions ...201526116245
genetic diversity of diplomonadida in fish of the genus coregonus from southeastern siberia.diplomonadida are primitive flagellate protozoa, among which both commensals and pathogens have been recorded. to date, members of the genera hexamita and spironucleus have been reported in the digestive system of fish in the baikal region. we determined the genetic diversity of diplomonadida in fish of the genus coregonus from south-eastern siberia using molecular-genetic methods. fish for analysis were caught in lake baikal and in the barguzin, nepa, chechuy, and kirenga rivers from 2010 to 20 ...201627078653
characterization of perch rhabdovirus (prv) in farmed grayling thymallus thymallus.two finnish fish farms experienced elevated mortality rates in farmed grayling thymallus thymallus fry during the summer months, most typically in july. the mortalities occurred during several years and were connected with a few neurological disorders and peritonitis. virological investigation detected an infection with an unknown rhabdovirus. based on the entire glycoprotein (g) and partial rna polymerase (l) gene sequences, the virus was classified as a perch rhabdovirus (prv). pairwise compar ...201324113245
evolution and regulation of the downstream gene of hypoxia-inducible factor-1alpha in naked carp (gymnocypris przewalskii) from lake qinghai, china.the naked carp (gymnocypris przewalskii) is a native teleost of lake qinghai (altitude, 3.2 km) on the qinghai-tibet plateau in china. hypoxia-inducible factor (hif)-1alpha of gymnocypris przewalskii was cloned and a phylogenetic tree for vertebrate hif-1alpha was constructed. by analysis of maximum likelihood models of codon substitutions for hif-1alpha, three positive sites in the branch lineages of crucian carp, eelpout, and flounder, and a higher proportion of neutral sites in naked carp, an ...200818941827
antimicrobial and host cell-directed activities of gly/ser-rich peptides from salmonid cathelicidins.cathelicidins, a major family of vertebrate antimicrobial peptides (amps), have a recognized role in the first line of defense against infections. they have been identified in several salmonid species, where the putative mature peptides are unusually long and rich in serine and glycine residues, often arranged in short multiple repeats (rlgggs/rpgggs) intercalated by hydrophobic motifs. fragments of 24-40 residues, spanning specific motifs and conserved sequences in grayling or brown, rainbow an ...201627818338
contemporary isolation-by-distance, but not isolation-by-time, among demes of european grayling (thymallus thymallus, linnaeus) with recent common ancestors.the development of isolation by distance (ibd) and isolation by time (ibt) was contrasted among demes of european grayling (thymallus thymallus) that have diverged within the last 25 generations following colonization of a lake (lesjaskogsvatnet). we find low but significant levels of genetic differentiation among spawning tributaries and a pattern of ibd among them. we do not, however, find evidence for ibt despite an up to four-week difference in spawning date between "warm/early" and "cold/la ...200919154368
susceptibility of selected freshwater fish species to a uk lactococcus garvieae isolate.gram-positive cocci recovered from diseased rainbow trout from a farm in england were characterized by different methods, including pulsed field gel electrophoresis, as virulent lactococcus garvieae serogroup 2 (pulsotype a1). groups of rainbow trout were kept at a range of temperatures and injected intraperitoneally (i.p.) with one of the uk isolates, l. garvieae 00021. the 18 degrees c and 16 degrees c groups showed 67% and 28% mortality, respectively, by day 27 post-injection. fish kept at 14 ...200919500233
mitochondrial haplotype diversity of gyrodactylus thymalli (platyhelminthes; monogenea): extended geographic sampling in united kingdom, poland, and norway reveals further lineages.in recent years, the mitochondrial haplotype diversity of the monogenean ectoparasites gyrodactylus salaris malmberg, 1957 on atlantic salmon and g. thymalli zitnan, 1960 on grayling has been studied intensively to understand the taxonomy and phylogeography of the two species. according to these studies, neither species can be considered monophyletic, but unfortunately, the geographic sampling has mostly been restricted to fennoscandia. only few samples from continental europe have been analysed ...200717216240
a risk-benefit analysis of wild fish consumption for various species in alaska reveals shortcomings in data and monitoring needs.northern peoples face a difficult decision of whether or not to consume wild fish, which may contain dangerous levels of contaminants such as methylmercury (mehg), but which also offer a number of positive health benefits, and play an important role in rural household economies. here, new methods for developing consumption advice are applied to an existing data-set for methylmercury (mehg) levels in alaskan fish. we apply a quantitative risk-benefit analysis for eight freshwater, saltwater and a ...201020673961
reconstructing mitochondrial genomes directly from genomic next-generation sequencing reads--a baiting and iterative mapping approach.we present an in silico approach for the reconstruction of complete mitochondrial genomes of non-model organisms directly from next-generation sequencing (ngs) data-mitochondrial baiting and iterative mapping (mitobim). the method is straightforward even if only (i) distantly related mitochondrial genomes or (ii) mitochondrial barcode sequences are available as starting-reference sequences or seeds, respectively. we demonstrate the efficiency of the approach in case studies using real ngs data s ...201323661685
microrna loci support conspecificity of gyrodactylus salaris and gyrodactylus thymalli (platyhelminthes: monogenea).the monogenean flatworm gyrodactylus salaris is a serious threat to wild and farmed atlantic salmon stocks in norway. morphologically, the closely related but harmless gyrodactylus thymalli on grayling can hardly be distinguished from g. salaris. until now, molecular approaches could not resolve unambiguously whether g. salaris and g. thymalli represent just one polytypic species, two polytypic species or a complex of more than two species. in the first known genome-wide analysis utilizing 37 co ...201424998346
genetic population structure of gyrodactylus thymalli (monogenea) in a large norwegian river system.the extent of geographic genetic variation is the result of several processes such as mutation, gene flow, selection and drift. processes that structure the populations of parasite species are often directly linked to the processes that influence the host. here, we investigate the genetic population structure of the ectoparasite gyrodactylus thymalli žitňan, 1960 (monogenea) collected from grayling (thymallus thymallus l.) throughout the river glomma, the largest watercourse in norway. parts of ...201526463886
reservoir hosts for gyrodactylus salaris may play a more significant role in epidemics than previously thought.gyrodactylus salaris malmberg, 1957 has had a devastating impact on wild norwegian stocks of atlantic salmon salmo salar l., and it is the only office international des epizooties (oie) listed parasitic pathogen of fish. the uk is presently recognised as g. salaris-free, and management plans for its containment and control are currently based on scandinavian studies. the current study investigates the susceptibility of british salmonids to g. salaris, and determines whether, given the host isola ...201425526740
oxygen dissociation and content of blood from alaskan burbott (lota lota), pike (esox lucius) and grayling (thymallus arcticus). 19734148985
hybrid origin of baltic salmon-specific parasite gyrodactylus salaris: a model for speciation by host switch for hemiclonal organisms.host switching explains the high species number of ectoparasitic, viviparous, mainly parthenogenetic but potentially hermaphroditic flatworms of the genus gyrodactylus. the starlike mitochondrial phylogeny of gyrodactylus salaris suggested parallel divergence of several clades on grayling (also named as gyrodactylus thymalli) and an embedded sister clade on baltic salmon. the hypothesis that the parasite switched from grayling to salmon during the glacial diaspora was tested using a 493-bp nucle ...200717971088
[genetic variation of the mtdna cyt b locus in graylings (thymalus sp.: thymalidae, pisces) introduced into the baydrag gol river of the valley of lakes basin (mongolia)].based on sequence variation of the mtdna cyt b gene, an analysis of graylings introduced from the arctic ocean basin (selenga river basin) into one of the rivers of central asian inland basin (baydrag goal river of the valley of lakes basin) was carried out. morphological and molecular genetic identification was performed, and it was established that the introduced species corresponded to the baikal grayling. the relationships among central asian grayling species are discussed.201526310033
analysis of fin clips as a nonlethal method for monitoring mercury in fish.monitoring of mercury in fish typically involves removal of individuals from the sampled population and subsequent analysis of fillets. this study assessed whether the analysis of fins, structures routinely clipped to mark released fish in population studies, could provide a nonlethal approach for estimating mercury concentrations in axial muscle (fillets). we analyzed fillets and selected fins from 401 northern pike (esox lucius) and 79 walleye (sander vitreus) from 21 lakes in minnesota and wi ...200818323115
comparative baseline levels of mercury, hsp 70 and hsp 60 in subsistence fish from the yukon-kuskokwim delta region of alaska.in subsistence fish; northern pike (esox lucius), burbot (lota lota), whitefish (coregonus nelsoni), grayling (thymallus arcticus) and sheefish (stenodus lencichthys), we determined the hsp 60 and hsp 70 levels in 31 samples from adult fish gills. a dot-blot analysis using antibodies to either hsp 70 or hsp 60 showed the average hsp 70 concentration was 9.1 microg/mg protein, while the average hsp 60 concentration was 147.4 microg/mg protein. mercury levels in muscle tissue in these fish average ...199910622434
improvement of common carp (cyprinus carpio) sperm cryopreservation using a programable freezer.the applicability of a programmable freezer for the increased-scale cryopreservation of common carp sperm was investigated. the effect of different equilibration times, cryopreservation methods, extenders, dilution ratios, activating solutions on the post-thaw motility of common carp sperm was investigated. the suitable post-thaw storage time-interval as well as fertilizing capacity of cryopreserved sperm was also examined. the motility, curvilinear velocity (vcl) and straightness (str) values d ...201627570061
habitat use by the fish assemblages of two chalk streamspatterns of habitat use by fish assemblages in two chalk streams in southern england were examined to identify species preferences with respect to major habitat gradients. both study sites, although differing in some physical habitat characteristics, mainly channel width, water temperature and instream cover, could be arranged similarly along a continuum extending from erosional to depositional habitats. twelve fish species were collected from stream surveys conducted during july 1993. the habit ...19979236089
organochlorine pesticides and polychlorinated biphenyls (pcbs) in sediments and biota from four us arctic lakes.organochlorine (oc) concentrations in surface sediment, snails (lymnea sp.), and two freshwater fish species (grayling, thymallus arcticus; and lake trout, salvelinus namaycush) from four lakes in the us arctic were determined. in surface sediment, chlorinated benzenes (including hexachlorobenzene, hcb), and p,p'-ddt were the primary analytes detected (max = 0.7 ng/g dry wt), while individual polychlorinated biphenyl (pcb) congeners were always below 0.1 ng/g. a wider range of compounds and high ...19979419256
occurrence of intersex in wild freshwater fish in slovenian rivers: a histological evaluation.the aim of this preliminary research was to establish if there are intersex occurrences in wild freshwater fish in slovenian rivers and streams. in the first study we evaluated all fish species of both sexes obtained from the river ljubljanica from its source to mouth. in the second study we focused on the rainbow trout (oncorhynchus mykiss) and brown trout (salmo trutta m. fario) males from 30 rivers and streams in different parts of slovenia. the male gonads were histologically assessed for th ...201627749265
[finding of the subarctic leeches, acanthobdella peledina and cystobranchus mammillatus, in the lake baikal basin and the reasons for their absence in lake baikal itself].acanthobdella peledina was first found in the basin of lake baikal on the fluvial form of the balkal grayling thymallus arcticus baicalensis and coregonus lavaretus pidschian from the upper angara. cystobranchus mammillatus, a parasite of burbot, is widely distributed in the tributaries of baikal. the absence of these subarctic leeches from baikal itself is explained by their rheophily.2007492778
cytological studies in thymallus thymallus and coregonus albula. 19715173403
henneguya cartilaginis n. sp. (myxozoa: myxosporea) in the head cartilage of masu salmon oncorhynchus masou masou.henneguya cartilaginis n. sp. (myxozoa: myxosporea) is described from wild masu salmon oncorhynchus masou masou in hokkaido, japan. h. cartilaginis n. sp. produced white cysts, up to 3mm in size, in the head of masu salmon. infected fish exhibited cranial protrusion due to the cysts. spores (11.4 × 8.6 μm) of h. cartilaginis n. sp. were egg-shaped with the posterior end more pointed and possessed two caudal appendages (34.2 μm average length). histological observations revealed that large plasmo ...201222664475
leech-like parasites (clitellata, acanthobdellida) infecting native and endemic eastern siberian salmon fishes.salmonoid fish bdellosis is caused by leech-like ectoparasites in the monogenetic order acanthobdellida. although acanthobdella species have been known to infect several threatened species in eurasia, little is known about their ecology and epidemiology. in this paper, we report on the mass affection (up to 70.7%) of fish in lower course of the chechuj river, a right tributary of the lena and provide information on finding acanthobdella peledina on two of six salmonoid fish species inhabiting th ...201222645444
[description of a new species of proteocephalus pronini sp.n. (cestoda: proteocephalidae)--a parasite of grayling from lake hovsgol].a new cestode species, proteocephalus pronini sp. n., is described from the lake hovsgol grayling thymallus arcticus nigrescens (mongolia, hovsgol lake). the new species differs from p. thymalli from the baikal lake by the length of strobile, number of proglottids, form of mature proglottids, and number of diverticles of uterus.200711548584
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