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[Alternative localization of the determinant of pathogenicity coded by the Yersinia pseudotuberculosis pVM82 plasmid]
Abstract:
The chromosomal DNA regions in Yersinia pseudotuberculosis strains occur that are homologous to 25 Md DNA segment of the plasmid pVM82 encoding the bacterial capability of immunosuppression. The character of the chromosomal DNA regions dispersion reacting with the 25 Md segment probes is different in epidemiologically hazardous and nonvirulent strains of Yersinia pseudotuberculosis. The specific DNA regions occur as well as identical ones. The suppression of antibody formation to a number of main Yersinia pseudotuberculosis antigens by epidemiologically hazardous strain is demonstrated. The suppression is analogous to the one previously described for Yersinia pseudotuberculosis strains harbouring the plasmid pVM82.
Insights
Epidemiologically hazardous Yersinia pseudotuberculosis strains possess chromosomal DNA homologous to immunosuppression-encoding plasmid pVM82. This genetic difference correlates with suppressed antibody formation in these virulent bacterial strains.
Area of Science:
- Microbiology
- Immunology
- Genetics
Background:
- Yersinia pseudotuberculosis is an opportunistic pathogen.
- Plasmid pVM82 confers immunosuppressive properties to bacteria.
- The genetic basis for immunosuppression in virulent strains is not fully understood.
Purpose of the Study:
- To investigate the chromosomal DNA regions in Yersinia pseudotuberculosis homologous to the immunosuppression-encoding plasmid pVM82.
- To compare the distribution of these homologous regions in virulent and nonvirulent strains.
- To confirm the immunosuppressive activity of virulent strains.
Main Methods:
- DNA hybridization using probes from the 25 Md DNA segment of plasmid pVM82.
- Analysis of chromosomal DNA dispersion patterns in different Yersinia pseudotuberculosis strains.
- Assessment of antibody formation suppression in response to Yersinia pseudotuberculosis antigens.
Main Results:
- Chromosomal DNA regions homologous to the 25 Md segment of pVM82 were identified in Yersinia pseudotuberculosis.
- The dispersion of these homologous regions differed between epidemiologically hazardous and nonvirulent strains.
- Epidemiologically hazardous strains demonstrated suppression of antibody formation to key antigens, similar to strains with pVM82.
Conclusions:
- Virulent Yersinia pseudotuberculosis strains harbor chromosomal DNA with homology to the immunosuppression-mediating plasmid pVM82.
- This genetic homology is associated with the observed immunosuppressive phenotype in hazardous strains.
- The findings suggest a chromosomal mechanism for immunosuppression in Yersinia pseudotuberculosis.