scholarly journals Both msa Genes in Renibacterium salmoninarum Are Needed for Full Virulence in Bacterial Kidney Disease

2006 ◽  
Vol 72 (4) ◽  
pp. 2672-2678 ◽  
Author(s):  
Alison M. Coady ◽  
Anthony L. Murray ◽  
Diane G. Elliott ◽  
Linda D. Rhodes
Keyword(s):  
Kidney Disease ◽  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Soluble Antigen ◽  
Renibacterium Salmoninarum ◽  
Juvenile Chinook Salmon ◽  
Bacterial Kidney Disease ◽  
Important Virulence Factor ◽  
Chromosomal Loci

ABSTRACT Renibacterium salmoninarum, a gram-positive diplococcobacillus that causes bacterial kidney disease among salmon and trout, has two chromosomal loci encoding the major soluble antigen (msa) gene. Because the MSA protein is widely suspected to be an important virulence factor, we used insertion-duplication mutagenesis to generate disruptions of either the msa1 or msa2 gene. Surprisingly, expression of MSA protein in broth cultures appeared unaffected. However, the virulence of either mutant in juvenile chinook salmon (Oncorhynchus tshawytscha) by intraperitoneal challenge was severely attenuated, suggesting that disruption of the msa1 or msa2 gene affected in vivo expression.

scholarly journals Identification of a Third msa Gene in Renibacterium salmoninarum and the Associated Virulence Phenotype

2004 ◽  
Vol 70 (11) ◽  
pp. 6488-6494 ◽  
Author(s):  
Linda D. Rhodes ◽  
Alison M. Coady ◽  
Rebecca K. Deinhard
Keyword(s):  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Culture Conditions ◽  
Nonuniform Distribution ◽  
Soluble Antigen ◽  
Renibacterium Salmoninarum ◽  
Juvenile Chinook Salmon ◽  
Bacterial Kidney Disease ◽  
Virulence Phenotype ◽  
Challenge Study

ABSTRACT Renibacterium salmoninarum, a gram-positive diplococcobacillus, causes bacterial kidney disease, a condition that can result in extensive morbidity and mortality among stocks of fish. An immunodominant extracellular protein, called major soluble antigen (MSA), is encoded by two identical genes, msa1 and msa2. We found evidence for a third msa gene, msa3, which appears to be a duplication of msa1. Unlike msa1 and msa2, msa3 is not present in all isolates of R. salmoninarum. The presence of the msa3 locus does not affect total MSA production in culture conditions. In a challenge study, isolates possessing the msa3 locus reduced median survival in juvenile chinook salmon (Oncorhynchus tshawytscha) by an average of 34% at doses of ≤105 cells per fish compared to isolates lacking the msa3 locus. In contrast, no difference in survival was observed at the highest dose, 106 cells per fish. The phenotype associated with the msa3 locus and its nonuniform distribution may contribute to observed differences in virulence among R. salmoninarum isolates.

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

2006 ◽  
Vol 63 (12) ◽  
pp. 2793-2808 ◽  
Author(s):  
Jeffrey J Hard ◽  
Diane G Elliott ◽  
Ronald J Pascho ◽  
Dorothy M Chase ◽  
Linda K Park ◽  
...  
Keyword(s):  
Kidney Disease ◽  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Enzyme Linked Immunosorbent Assay ◽  
Antigen Level ◽  
Renibacterium Salmoninarum ◽  
Listonella Anguillarum ◽  
Bacterial Kidney Disease ◽  
Genetic And Phenotypic Correlations ◽  
High Heritability

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.

Vulnerability to predation and physiological stress responses in juvenile chinook salmon (Oncorhynchus tshawytscha) experimentally infected with Renibacterium salmoninarum

1998 ◽  
Vol 55 (7) ◽  
pp. 1599-1606 ◽  
Author(s):  
Matthew G Mesa ◽  
Thomas P Poe ◽  
Alec G Maule ◽  
Carl B Schreck
Keyword(s):  
Stress Responses ◽  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Physiological Stress ◽  
Smallmouth Bass ◽  
Control Fish ◽  
Infection Level ◽  
Renibacterium Salmoninarum ◽  
Juvenile Chinook Salmon ◽  
Juvenile Chinook

We experimentally infected juvenile chinook salmon (Oncorhynchus tshawytscha) with Renibacterium salmoninarum (Rs), the causative agent of bacterial kidney disease (BKD), to examine the vulnerability to predation of fish with differing levels of Rs infection and assess physiological change during progression of the disease. Immersion challenges conducted during 1992 and 1994 produced fish with either a low to moderate (1992) or high (1994) infection level of Rs during the 14-week postchallenge rearing period. When equal numbers of treatment and unchallenged control fish were subjected to predation by either northern squawfish (Ptychocheilus oregonensis) or smallmouth bass (Micropterus dolomieui), Rs-challenged fish were eaten in significantly greater numbers than controls by nearly two to one. In 1994, we also sampled fish every 2 weeks after the challenge to determine some stressful effects of Rs infection. During disease progression in fish, plasma cortisol and lactate increased significantly whereas glucose decreased significantly. Our results indicate the role that BKD may play in predator-prey interactions, thus ascribing some ecological significance to this disease beyond that of direct pathogen-related mortality. In addition, the physiological changes observed in our fish during the chronic progression of BKD indicate that this disease is stressful, particularly during the later stages.

Antibiotic Toxicity, Efficacy, and Teratogenicity in Adult Spring Chinook Salmon (Oncorhynchus tshawytscha)

1972 ◽  
Vol 29 (11) ◽  
pp. 1513-1517 ◽  
Author(s):  
Mark G. DeCew
Keyword(s):  
Kidney Disease ◽  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Fold Increase ◽  
Penicillin G ◽  
Adult Survival ◽  
Bacterial Kidney Disease

Antibiotics were tested for toxicity and efficacy in adult spring chinook salmon (Oncorhynchus tshawytscha) infected with bacterial kidney disease and furunculosis. The complex of penicillin G procaine, dihydrostreptomycin sulfate, and oxytetracycline-HCl was not toxic and it effectively controlled both diseases, producing a three-fold increase in adult survival and production of viable eggs.Mandible and fin teratogenesis occurred in progeny of adults treated with the above antibiotic complex, but could be reduced by providing a 32 day interim between injection and spawning.

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