Geology Reports⌕ Search

Geology topics

J. L. Bartholomew

Publications and source records attributed to J. L. Bartholomew.

9 recordsLinked to original sources
USGS2009

Propagation of the myxozoan parasite Myxobolus cerebralis by different geographic and genetic populations of Tubifex tubifex: An Oregon perspective

Tubifex tubifex are obligate invertebrate hosts in the life cycle of Myxobolus cerebralis, the myxozoan parasite that causes whirling disease in salmonid fishes. This exotic parasite is established to varying degrees across Oregon's Columbia River system (Pacific Northwest, USA) and characteristics of local T. tubifex populations likely play a role in the pattern of disease occurrence. To better understand these patterns, we collected T. tubifex from three Oregon river basins (Willamette, Deschutes, and Grande Ronde), determined their genotype (mitochondrial 16S rDNA lineage and RAPD genotype) and exposed 10 different populations to M. cerebralis in the laboratory. Four mt lineages were identified: I, III, V and VI. Lineage III was found in all river basins but dominated both central and eastern sites. The RAPD assay further divided these lineages into geographic sub-populations; no RAPD genotype was common to all basins. There was a significant difference in prevalence of infection and level of parasite production among the populations we exposed to M. cerebralis that was attributed to genotypic composition. Only lineage III worms released actinospores and only populations dominated by this lineage amplified the parasite. These populations had the lowest survival, however, the lineage dominant before exposure remained dominant despite the high prevalence of infection. The distribution and infection dynamics of susceptible T. tubifex throughout Oregon may contribute to the differences in M. cerebralis occurrence; our studies further support the influence of oligochaete genotypes on the manifestation of whirling disease in salmonid populations. ?? 2009 Elsevier Inc. All rights reserved.

Journal of Invertebrate Pathology↗
USGS2006

Characterization of the host response to the myxosporean parasite, Ceratomyxa shasta (Noble), by histology, scanning electron microscopy, and immunological techniques

The tissue response of Salmo gairdneri Richardson, against the myxosporean parasite. Ceratomyxa shasta (Noble), was investigated using histological techniques, scanning electron microscopy and immunological methods. The progress of infection in C. shasta ‐susceptible and resistant steelhead and rainbow trout was examined by standard histological techniques and by indirect fluorescent antibody methods using monoclonal antibodies directed against C. shasta antigens. Trophozoite stages were first observed in the posterior intestine and there was indication that resistance was due to the inability of the parasite to penetrate this tissue rather than to an inflammatory response. Examination of a severely infected intestine by scanning electron microscopy showed extensive destruction of the mucosal folds of the posterior intestine. Western blotting and indirect fluorescent antibody techniques were used to investigate the immunological component of the host response. No antibodies specific for C. shasta were detected by either method.

Journal of Fish Diseases↗
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↗
USGS1999

Relative virulence of three isolates of Piscirickettsia salmonis for coho salmon Oncorhynchus kisutch

Piscirickettsia salmonis was first recognized as the cause of mortality among pen-reared coho salmon Oncorhynchus kisutch in Chile. Since the initial isolation of this intracellular Gram-negative bacterium in 1989, similar organisms have been described from several areas of the world, but the associated outbreaks were not reported to be as serious as those that occurred in Chile. To determine if this was due to differences in virulence among isolates of P. salmonis , we conducted an experiment comparing isolates from Chile, British Columbia, Canada, and Norway (LF-89, ATL-4-91 and NOR-92, respectively). For each of the isolates, 3 replicates of 30 coho salmon were injected intraperitoneally with each of 3 concentrations of the bacterium. Negative control fish were injected with MEM-10. Mortalities were collected daily for 41 d post-injection. Piscirickettsiosis was observed in fish injected with each of the 3 isolates, and for each isolate, cumulative mortality was directly related to the concentration of bacterial cells administered. The LF-89 isolate was the most virulent, with losses reaching 97% in the 3 replicates injected with 105.0 TCID50, 91% in the replicates injected with 104.0 TCID50, and 57% in the fish injected with 103.0 TCID50. The ATL-4-91 isolate caused losses of 92% in the 3 replicates injected with 105.0 TCID50, 76% in the fish injected with 104.0 TCID50, and 32% in those injected with 103.0 TCID50. The NOR-92 isolate was the least virulent, causing 41% mortality in the replicates injected with 104.6 TCID50. At 41 d post-injection, 6% of the fish injected with 103.6 TCID50 NOR-92 had died. Mortality was only 2% in the fish injected with 102.6 TCID50 NOR-92, which was the same as the negative control group. Because the group injected with the highest concentration (104.6 TCID50) of NOR-92 was still experiencing mortality at 41 d, it was held for an additional 46 d. At 87 d post-injection, the cumulative mortality in this group had reached 70%. These differences in virulence among the isolates were statistically significant (p < 0.0001), and are important for the management of affected stocks of fish.

Diseases of Aquatic Organisms↗
USGS1992

Prevalence of Renibacterium salmoninarum among downstream-migrating salmonids in the Columbia River

Bacterial kidney disease (BKD) is an important contributor to mortality of salmonids in hatcheries in the Columbia River basin. However, the impact of BKD on the survival of downstream migrants is difficult to determine because there is little information on the disease-related mortality among these fish. In this study, the impact of BKD on juvenile salmonids was examined by determining the percentage of downriver migrants infected with Renibacterium salmoninarum (the causative agent of BKD) and evaluating the effects of salt water on the progress of the disease. During the 2 years of this study, approximately 20% of the three species of migrating hatchery and wild salmonids ( Oncorhynchus spp.) collected were infected with R. salmoninarum . Mortality caused by BKD increased when fish were held in salt water.

Journal of Aquatic Animal Health↗
USGS1991

Demonstration of the salmonid humoral response to Renibacterium salmoninarum using a monoclonal antibody against salmonid immunoglobulin

The specificity of the antibody response of salmonids to Renibacterium salmoninarum antigens was demonstrated by western blotting techniques that utilized a monoclonal antibody against salmonid immunoglobulin. In this study, the specificity of the response in immunized chinook salmon Oncorhynchus tshawytscha was compared with the response in naturally infected chinook salmon and coho salmon O. kisutch , and immunized rabbits. The antibody response in immunized salmon and rabbits and the naturally infected fish was primarily against the 57–58kilodalton protein complex. In addition to recognizing these proteins in the extracellular fraction and whole-cell preparations, antibody from the immunized salmon and rabbits detected four proteins with lower molecular masses. Western blotting techniques allow identification of the specific antigens recognized and are a useful tool for comparing the immunogenicity of different R. salmoninarum preparations. Immunofluorescent techniques with whole bacteria were less sensitive than western blotting in detecting salmonid anti- R. salmoninarum antibody.

Journal of Aquatic Animal Health↗
USGS1989

Development, characterization, and use of monoclonal and polyclonal antibodies against the myxosporean, Ceratomyxa shasta

Both monoclonal and polyclonal antisera were produced against Ceratomyxa shasta. Ascites containing trophozoites of the parasite was collected from infected fish and used as antigen for immunization of mice. The resulting monoclonal antibodies reacted specifically with trophozoite and sporoblast stages but did not react with C. shasta spores by either indirect fluorescent antibody techniques or in Western blots. This indicates that some C. shasta antigens are specific to certain life stages of the parasite. Polyclonal antiserum was produced in a rabbit by injecting a spore protein electro-eluted from an SDS-polyacrylamide gel. This antiserum reacted with both trophozoites and spores by indirect fluorescent antibody techniques and in Western blots. All antisera were tested for cross-reactivity to trout white blood cells, a contaminant of the ascites, and to other myxosporea. Two monoclonal antibodies reacted with white blood cells and myxosporea of the genera Sphaerospora and Myxobilatus. One hybridoma produced antibodies of high specificity for C. shasta pre-spore stages. This is the first report of a monoclonal antibody produced against a myxosporean parasite.

Journal of Eukaryotic Microbiology↗