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Geology topics

J. R. Winton

Publications and source records attributed to J. R. Winton.

At least 37 records · Page 2Linked to original sources
USGS2006

Genetic effects of ELISA-based segregation for control of bacterial kidney disease in Chinook salmon (Oncorhynchus tshawytscha)

We evaluated genetic variation in ability of Chinook salmon (Oncorhynchus tshawytscha) to resist two bacterial pathogens: Renibacterium salmoninarum, the agent of bacterial kidney disease (BKD), and Listonella anguillarum, an agent of vibriosis. After measuring R. salmoninarum antigen in 499 adults by enzyme-linked immunosorbent assay (ELISA), we mated each of 12 males with high or low antigen levels to two females with low to moderate levels and exposed subsets of their progeny to each pathogen separately. We found no correlation between R. salmoninarum antigen level in parents and survival of their progeny following pathogen exposure. We estimated high heritability for resistance to R. salmoninarum (survival h2 = 0.890 ?? 0.256 (mean ?? standard error)) independent of parental antigen level, but low heritability for resistance to L. anguillarum (h2 = 0.128 ?? 0.078). The genetic correlation between these survivals (rA = -0.204 ?? 0.309) was near zero. The genetic and phenotypic correlations between survival and antigen levels among surviving progeny exposed to R. salmoninarum were both negative (rA = -0.716 ?? 0.140; rP = -0.378 ?? 0.041), indicating that variation in antigen level is linked to survival. These results suggest that selective culling of female broodstock with high antigen titers, which is effective in controlling BKD in salmon hatcheries, will not affect resistance of their progeny. ?? 2006 NRC.

Canadian Journal of Fisheries and Aquatic Sciences↗
USGS2006

Interactions among two strains of Tubifex tubifex (Oligochaeta: Tubificidae) and Myxobolus cerebralis (Myxozoa)

Host-parasite interactions influence host population growth, host evolution and parasite success. We examined the interactions among Myxobolus cerebralis, the parasite that causes salmonid whirling disease, and resistant and susceptible strains of the oligochaete host Tubifex tubifex. Strains of T. tubifex with diverse genotypes often coexist in nature and have variable susceptibilities to M. cerebralis infection. Further, parasite proliferation differs by several orders of magnitude among T. tubifex strains. We examined total biomass produced by individual T. tubifex, including progeny production and adult growth, parasite proliferation and prevalence of infection using 2 strains of T. tubifex at 2 myxospore doses in a response-surface experimental design. Total biomass production per individual oligochaete and progeny biomass produced by an individual adult oligochaete were density-dependent for both resistant and susceptible individuals and the effects did not change with the addition of myxospores. However, both resistant and susceptible adults had highest growth when exposed to M. cerebralis. The presence of resistant oligochaetes in mixed cultures did not reduce the infection prevalence or parasite proliferation in susceptible individuals. In natural aquatic communities, resistant strains of T. tubifex may not reduce the effects of M. cerebralis on the salmonid host, particularly if sufficient numbers of susceptible T. tubifex are present. ?? Inter-Research 2006.

Diseases of Aquatic Organisms↗
USGS2005

Sequence motifs and prokaryotic expression of the reptilian paramyxovirus fusion protein

Fourteen reptilian paramyxovirus isolates were chosen to represent the known extent of genetic diversity among this novel group of viruses. Selected regions of the fusion (F) gene were sequenced, analyzed and compared. The F gene of all isolates contained conserved motifs homologous to those described for other members of the family Paramyxoviridae including: signal peptide, transmembrane domain, furin cleavage site, fusion peptide, N-linked glycosylation sites, and two heptad repeats, the second of which (HRB-LZ) had the characteristics of a leucine zipper. Selected regions of the fusion gene of isolate Gono-GER85 were inserted into a prokaryotic expression system to generate three recombinant protein fragments of various sizes. The longest recombinant protein was cleaved by furin into two fragments of predicted length. Western blot analysis with virus-neutralizing rabbit-antiserum against this isolate demonstrated that only the longest construct reacted with the antiserum. This construct was unique in containing 30 additional C-terminal amino acids that included most of the HRB-LZ. These results indicate that the F genes of reptilian paramyxoviruses contain highly conserved motifs typical of other members of the family and suggest that the HRB-LZ domain of the reptilian paramyxovirus F protein contains a linear antigenic epitope. ?? Springer-Verlag 2005.

Archives of Virology↗
USGS2005

Combined use of the ASK and SHK-1 cell lines to enhance the detection of infectious salmon anemia virus

Infectious salmon anemia (ISA) is a severe disease primarily affecting commercially farmed Atlantic salmon (Salmo salar) in seawater. The disease has been reported in portions of Canada, the United Kingdom, the Faroe Islands, and the United States. Infectious salmon anemia virus (ISAV), the causative agent of ISA, has also been isolated from several asymptomatic marine and salmonid fish species. Diagnostic assays for the detection of ISAV include virus isolation in cell culture, a reverse transcriptase-PCR, an enzyme-linked immunosorbent assay, and an indirect fluorescent antibody test. Virus isolation is considered the gold standard, and 5 salmonid cell lines are known to support growth of ISAV. In this study, the relative performance of the salmon head kidney 1 (SHK-1), Atlantic salmon kidney (ASK), and CHSE-214 cell lines in detecting ISAV was evaluated using samples from both experimentally and naturally infected Atlantic salmon. Interlaboratory comparisons were conducted using a quality control-quality assurance ring test. Both the ASK and SHK-1 cell lines performed well in detecting ISAV, although the SHK-1 line was more variable in its sensitivity to infection and somewhat slower in the appearance of cytopathic effect. Relative to the SHK-1 and ASK lines, the CHSE-214 cell line performed poorly. Although the ASK line appeared to represent a good alternative to the more commonly used SHK-1 line, use of a single cell line for diagnostic assays may increase the potential for false-negative results. Thus, the SHK-1 and ASK cell lines can be used in combination to provide enhanced ability to detect ISAV.

Journal of Veterinary Diagnostic Investigation↗
USGS2005

Fish can get diseases too

Infectious diseases are increasingly recognized as an important component of the ecology of fish in the wild. Many of the viral, bacterial, protozoan and fungal pathogens of fish that were initially discovered in captive fish have their origin among wild populations; however, the impact of disease among these free-ranging stocks has been difficult to study. At the WFRC, combinations of field and laboratory investigations, aided by the tools of molecular biology, have begun to provide information on the ecology of infectious diseases among natural populations of fish in both freshwater and marine ecosystems.

Fact Sheet↗
USGS2004

High doses of corticosteroid suppress resistance to Ichthyophonus in starry flounder

Application of pharmacological doses of the corticosteroid dexamethasone phosphate to starry flounder Platichthys stellatus resulted in a predisposition to clinical ichthyophoniasis and a progression from latent Ichthyophonus infections to patent, histologically identifiable infections. Among Ichthyophonus -challenged starry flounder, the prevalences of clinical infections and histologically identifiable infections were significantly greater in two groups that received dexamethasone (100% and 31%, respectively) than in the respective control groups (8% and 0%). Proliferation of Ichthyophonus infections in corticosteroid-treated groups may have resulted from suppression of the cellular immune response that typically follows corticosteroid application; however, further studies are needed to determine whether these effects occur at lower, physiological concentrations of corticosteroids.

Journal of Aquatic Animal Health↗
USGS2004

Complete genome sequence of Fer-de-Lance Virus reveals a novel gene in reptilian Paramyxoviruses

The complete RNA genome sequence of the archetype reptilian paramyxovirus, Fer-de-Lance virus (FDLV), has been determined. The genome is 15,378 nucleotides in length and consists of seven nonoverlapping genes in the order 3??? N-U-P-M-F-HN-L 5???, coding for the nucleocapsid, unknown, phospho-, matrix, fusion, hemagglutinin-neuraminidase, and large polymerase proteins, respectively. The gene junctions contain highly conserved transcription start and stop signal sequences and tri-nucleotide intergenic regions similar to those of other Paramyxoviridae. The FDLV P gene expression strategy is like that of rubulaviruses, which express the accessory V protein from the primary transcript and edit a portion of the mRNA to encode P and I proteins. There is also an overlapping open reading frame potentially encoding a small basic protein in the P gene. The gene designated U (unknown), encodes a deduced protein of 19.4 kDa that has no counterpart in other paramyxoviruses and has no similarity with sequences in the National Center for Biotechnology Information database. Active transcription of the U gene in infected cells was demonstrated by Northern blot analysis, and bicistronic N-U mRNA was also evident. The genomes of two other snake paramyxovirus genotypes were also found to have U genes, with 11 to 16% nucleotide divergence from the FDLV U gene. Pairwise comparisons of amino acid identities and phylogenetic analyses of all deduced FDLV protein sequences with homologous sequences from other Paramyxoviridae indicate that FDLV represents a new genus within the subfamily Paramyxovirinae. We suggest the name Ferlavirus for the new genus, with FDLV as the type species.

Journal of Virology↗
USGS2004

Differential propagation of the metazoan parasite Myxobolus cerebralis by Limnodrilus hoffmeisteri, Ilyodrilus templetoni, and genetically distinct strains of Tubifex tubifex

Whirling disease, caused by the parasite Myxobolus cerebralis, has infected rainbow trout (Oncorhynchus mykiss) and other salmonid fish in the western United States, often with devastating results to native populations but without a discernible spatial pattern. The parasite develops in a complex 2-host system in which the aquatic oligochaete Tubifex tubifex is an obligate host. Because substantial differences in whirling disease severity in different areas of North America did not seem explainable by environmental factors or features of the parasite or its fish host, we sought to determine whether ecological or genetic variation within oligochaete host populations may be responsible. We found large differences in compatibility between the parasite and various laboratory strains of T. tubifex that were established from geographic regions with different whirling disease histories. Moreover, 2 closely related species of tubificids, Limnodrilus hqffmeisteri and Ilyodrilus templetoni, which occur naturally in mixed species assemblages with T. tubifex, were incompatible with M. cerebralis. Virulence of the parasite was directly correlated with the numbers of triactinomyxon spores that developed within each strain of T. tubifex. Thus, the level of virulence was directly related to the compatibility between the host strain and the parasite. Genetic analyses revealed relationships that were in agreement with the level of parasite production. Differences in compatibilities between oligochaetes and M. cerebralis may contribute to the spatial variance in the severity of the disease among salmonid populations. ?? American Society of Parasitologists 2004.

Journal of Parasitology↗
USGS2004

Molecular characterization of birnaviruses isolated from wild marine fishes at the Flemish Cap (Newfoundland)

Several isolates of aquatic birnaviruses were recovered from different species of wild fish caught in the Flemish Cap, a Newfoundland fishery close to the Atlantic coast of Canada. The nucleotide sequence of a region of the NS gene was identical among the isolates and was most similar to the Dry Mills and West Buxton reference strains of infectious pancreatic necrosis virus (IPNV). Phylogenetic analysis of the sequence of a region of the VP2 gene demonstrated that the isolates were most closely aligned with the American strains of IPNV serotype Al. Electron microscopy of virus structures clarified and concentrated from cultures of infected chinook salmon embryo (CHSE-214) cells revealed a majority of typical IPNV-like icosahedral particles, as well as a low proportion of type I tubules having a diameter of approximately 55 nm and a variable length of up to 2 µm . The tubules could be propagated in cell cultures, but always in the presence of low proportions of icosahedral particles. Cloning of selected isolates by serial dilution yielded preparations with a high proportion of the tubular structures with a density in CsCl gradients of approximately 1.30 g cm -3 . Polyacrylamide gel electrophoresis revealed the material in the band was composed of the IPNV pVP2 and VP2 proteins.

Flemish Cap↗
USGS2003

Relative resistance of Pacific salmon to infectious salmon anaemia virus

Infectious salmon anaemia (ISA) is a major disease of Atlantic salmon, Salmo salar, caused by an orthomyxovirus (ISAV). Increases in global aqua culture and the international movement of fish made it important to determine if Pacific salmon are at risk. Steelhead trout, Oncorhynchus mykiss, and chum, O. keta, Chinook, O. tshawytscha, coho, O. kisutch, and Atlantic salmon were injected intraperitoneally with a high, medium, or low dose of a Norwegian strain of ISAV. In a second challenge, the same species, except chum salmon, were injected with a high dose of either a Canadian or the Norwegian strain. Average cumulative mortality of Atlantic salmon in trial 1 was 12% in the high dose group, 20% in the medium dose group and 16% in the low dose group. The average cumulative mortality of Atlantic salmon in trial 2 was 98%. No signs typical of ISA and no ISAV-related mortality occurred among any of the groups of Oncorhynchus spp. in either experiment, although ISAV was reisolated from some fish sampled at intervals post-challenge. The results indicate that while Oncorhynchus spp. are quite resistant to ISAV relative to Atlantic salmon, the potential for ISAV to adapt to Oncorhynchus spp. should not be ignored.

Journal of Fish Diseases↗
USGS2003

Host and geographic range extensions of the North American strain of viral hemorrhagic septicemia virus

Viral hemorrhagic septicemia virus (VHSV) was isolated from populations of Pacific sardine Sardinops sagax from the coastal waters of Vancouver Island, British Columbia, Canada, and central and southern California, USA. The virus was also isolated from Pacific mackerel Scomber japonicus in southern California, from eulachon or smelt Thaleichthys pacificus , and surf smelt Hypomesus pretiosus pretiosus from Oregon, USA. Mortality and skin lesions typical of viral hemorrhagic septicemia in other marine fish species were observed among sardine in Canada and in a few surf smelt from Oregon, but the remaining isolates of VHSV were obtained from healthy appearing fish. The prevalence of VHSV among groups of apparently healthy sardine, mackerel and smelt ranged from 4 to 8% in California and Oregon. A greater prevalence of infection (58%) occurred in groups of sardine sampled in Canada that sustained a naturally occurring epidemic during 1998-99. A captive group of surf smelt in Oregon exhibited an 81% prevalence of infection with clinical signs in only a few fish. The new isolates were confirmed as North American VHSV and were closely related based on comparisons of the partial nucleotide sequence of the glycoprotein (G) gene. The VHSV isolates from sardine in Canada and California were the most closely related, differing from isolates obtained from other marine fish species and salmonids in British Columbia, Canada, Alaska and Washington, USA. These new virus isolations extend both the known hosts (sardine, mackerel and 2 species of smelt) and geographic range (Oregon and California, USA) of VHSV.

Diseases of Aquatic Organisms↗
USGS2002

Status and opportunities for genomics research with rainbow trout

The rainbow trout (Oncorhynchus mykiss) is one of the most widely studied of model fish species. Extensive basic biological information has been collected for this species, which because of their large size relative to other model fish species are particularly suitable for studies requiring ample quantities of specific cells and tissue types. Rainbow trout have been widely utilized for research in carcinogenesis, toxicology, comparative immunology, disease ecology, physiology and nutrition. They are distinctive in having evolved from a relatively recent tetraploid event, resulting in a high incidence of duplicated genes. Natural populations are available and have been well characterized for chromosomal, protein, molecular and quantitative genetic variation. Their ease of culture, and experimental and aquacultural significance has led to the development of clonal lines and the widespread application of transgenic technology to this species. Numerous microsatellites have been isolated and two relatively detailed genetic maps have been developed. Extensive sequencing of expressed sequence tags has begun and four BAC libraries have been developed. The development and analysis of additional genomic sequence data will provide distinctive opportunities to address problems in areas such as evolution of the immune system and duplicate genes. ?? 2002 Elsevier Science Inc. All rights reserved.

Conference Paper↗
USGS2002

Optimization of nested polymerase chain reaction assays for identification of Aeromonas salmonicida, Yersinia ruckeri and Flavobacterium psychrophilum

Nested polymerase chain reaction (PCR) assays were developed using first-round primers complementary to highly conserved regions within the bacterial 16S ribosomal RNA (rRNA) gene (universal eubacterial primers) and second-round primers specific for sequences within the 16S rRNA genes of Aeromonas salmonicida , Yersinia ruckeri , and Flavobacterium psychrophilum . Following optimization of the MgCl 2 concentration and primer annealing temperature, PCR employing the universal eubacterial primers was used to amplify a 1,500-base-pair (bp) product visible in agarose gels stained with ethidium bromide. The calculated detection limit of this single-round assay was less than 1.4 × 10 4 colony-forming units (CFU) per reaction for all bacterial species tested. Single-round PCR using primer sets specific for A. salmonicida , Y. ruckeri , and F. psychrophilum amplified bands of 271, 575, and 1,100 bp, respectively, with detection limits of less than 1.4 × 10 4 , 1.4 × 10 5 , and 1.4 × 10 5 CFU per reaction. Using the universal eubacterial primers in the first round and the species-specific primer sets in the second round of nested PCR assays improved the detection ability by approximately four orders of magnitude to fewer than 14 CFU per sample for each of the three bacterial species. Such nested assays could be adapted to a wide variety of bacterial fish pathogens for which 16S sequences are available.

Journal of Aquatic Animal Health↗
USGS2002

Spring viremia of carp

pring viremia of carp (SVC) is an important disease affecting cyprinids, mainly common carp Cyprinus carpio . The disease is widespread in European carp culture, where it causes significant morbidity and mortality. Designated a notifiable disease by the Office International des Epizooties, SVC is caused by a rhabdovirus, spring viremia of carp virus (SVCV). Affected fish show destruction of tissues in the kidney, spleen and liver, leading to hemorrhage, loss of water-salt balance and impairment of immune response. High mortality occurs at water temperatures of 10 to 17°C, typically in spring. At higher temperatures, infected carp develop humoral antibodies that can neutralize the spread of virus and such carp are protected against re-infection by solid immunity. The virus is shed mostly with the feces and urine of clinically infected fish and by carriers. Waterborne transmission is believed to be the primary route of infection, but bloodsucking parasites like leeches and the carp louse may serve as mechanical vectors of SVCV. The genome of SVCV is composed of a single molecule of linear, negative-sense, single-stranded RNA containing 5 genes in the order 3¹-NPMGL-5¹ coding for the viral nucleoprotein, phosphoprotein, matrix protein, glycoprotein, and polymerase, respectively. Polyacrylamide gel electrophoresis of the viral proteins, and sequence homologies between the genes and gene junctions of SVCV and vesicular stomatitis viruses, have led to the placement of the virus as a tentative member of the genus Vesiculovirus in the family Rhabdoviridae . These methods also revealed that SVCV is not related to fish rhabdoviruses of the genus Novirhabdovirus . In vitro replication of SVCV takes place in the cytoplasm of cultured cells of fish, bird and mammalian origin at temperatures of 4 to 31°C, with an optimum of about 20°C. Spring viremia of carp can be diagnosed by clinical signs, isolation of virus in cell culture and molecular methods. Antibodies directed against SVCV react with the homologous virus in serum neutralization, immunofluorescence, immunoperoxidase, or enzyme-linked immunosorbent assays, but they cross-react to various degrees with the pike fry rhabdovirus (PFR), suggesting the 2 viruses are closely related. However, SVCV and PFR can be distinguished by certain serological tests and molecular methods such as the ribonuclease protection assay.

Diseases of Aquatic Organisms↗
USGS2002

Elevated temperature exacerbates Ichthyophonus infections in buffalo sculpin

High incidences of Ichthyophonus hoferi, a parasite primarily of marine and estuarine fishes, have recently been reported in rockfishes and Pacific herring from the eastern North Pacific (Kent et al 2001, Hershberger et al 2002). Taxonomic position of I. hoferi remains unresolved, but recent phylogenetic studies have grouped the organism with Dermocystidium, Psorospermium, the rosette agent of salmonids, and Rhinosporidium in the Mesomycetozoa, a novel clade of protists near the animal-fungal divergence (Herr et al 1999). Genetic differences among isolates from the east coast of North America indicate that more than one species of Ichthyophonus exist (Rand et al 2000), and different species have likely been assigned the same name based on morphological characteristics. Therefore, hereafter in this manuscript, the organism will be referred to as Ichthyophonus .

Fish Health Newsletter↗
USGS2001

Negligible risk associated with the movement of processed rainbow trout, Oncorhynchus mykiss (Walbaum), from an infectious haematopoietic necrosis virus (IHNV) endemic area

To assess the risk of transmission of infectious haematopoietic necrosis virus (IHNV) associated with the movement of processed rainbow trout, Oncorhynchus mykiss, from an area where the virus is endemic, 240 freshly eviscerated fish (225-500 g) exhibiting spinal curvature or spinal compression types of deformities were tested for IHNV by virus isolation and polymerase chain reaction (PCR) techniques. Commercially produced rainbow trout, approximately 1-year-old, that exhibited spinal deformities were considered to have had a high likelihood of having survived an outbreak of IHN. Serological analysis of fish exhibiting spinal curvature or spinal compression types of deformities for anti-IHNV antibodies resulted, in 71 and 50% of the serum samples, respectively, with detectable neutralization activity suggesting previous infection with IHNV. A portion of the skin and muscle in the area of the deformity was collected, as well as brain tissue from each commercially processed fish. Tissue homogenates were tested for IHNV using the epithelioma papulosum cyprini (EPC) cell line pretreated with polyethylene glycol and the chinook salmon embryo (CHSE-214) cell line using standard methods. Nested, reverse transcriptase (RT)-PCR for the detection of IHNV used the central 1231 bp portion of the glycoprotein (G) challenge studies and is suggested as a mechanism responsible for virus clearance. These results provide scientific information that can be used to assess the risk associated with the movement of processed rainbow trout from an IHNV endemic area.

Journal of Fish Diseases↗