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[A new pathogenic trait encoded by Yersinia pseudotuberculosis pVM82 plasmid]
Abstract:
The strains of Yersinia pseudotuberculosis isolated from patients in the course of outbreaks of infection (epidemic strains) were found to possess at least two plasmids with molecular masses of 45 and 82 MD. In contrast, the strains obtained in sporadic cases harbored different sets of plasmids, but never the 82 MD plasmids. These plasmids designated pVM82 and isolated from strains of different geographic regions of the country were identical. pVM82 have no homology with Y. pestis plasmids of the similar size coding for the FraI antigen. The pVM82 DNA was found to be composed of the 57 MD plasmid DNA and the 25 MD fragment of Y. pseudotuberculosis DNA. Using Western blot hybridization technique it was shown that the presence of pVM82 suppressed formation of antibody against some major antigenic determinants of Y. pseudotuberculosis. Immunosuppression took place when the animals were infected with bacteria grown below 20 but not at 37 degrees C. The 57 MD plasmid failed to produce immunosuppression. It was concluded that the 25 MD fragment of pFN82 encoded a novel pathogenic factor responsible for immunosuppression.
Insights
Epidemic Yersinia pseudotuberculosis strains carry unique 82 MD plasmids (pVM82) not found in sporadic cases. This plasmid contains a novel 25 MD fragment responsible for immunosuppression in Yersinia infections.
Area of Science:
- Microbiology
- Immunology
- Molecular Biology
Context:
- Yersinia pseudotuberculosis is an important bacterial pathogen.
- Epidemic strains of Y. pseudotuberculosis possess distinct plasmid profiles compared to sporadic strains.
- Plasmids play a significant role in bacterial virulence and pathogenicity.
Purpose:
- To characterize the plasmids found in epidemic and sporadic strains of Yersinia pseudotuberculosis.
- To investigate the role of the 82 MD plasmid (pVM82) in Y. pseudotuberculosis pathogenicity.
- To identify the genetic basis for immunosuppression associated with pVM82.
Summary:
- Epidemic Yersinia pseudotuberculosis strains harbor 45 MD and 82 MD plasmids (pVM82), while sporadic strains lack pVM82.
- pVM82, composed of a 57 MD plasmid and a 25 MD DNA fragment, shows no homology with Y. pestis plasmids.
- The 25 MD fragment of pVM82 encodes a novel pathogenic factor responsible for Y. pseudotuberculosis-induced immunosuppression, particularly at lower temperatures.
Impact:
- Identifies a novel virulence factor in Yersinia pseudotuberculosis contributing to disease pathogenesis.
- Provides insights into the genetic mechanisms underlying Yersinia-mediated immunosuppression.
- Highlights the importance of plasmid-borne genes in bacterial adaptation and virulence.