title: [Biological properties of plasmid-free strains of Salmonella typhimurium and S. dublin].
abstract: The study of Salmonella virulent strains has revealed that the characteristic feature of such strains is the presence of plasmids with a molecular weight of 90.2-91.5 kb for S. typhimurium and 77.2-78.5 kb for S. dublin. From Salmonella strains harboring only a single plasmid, variants with no plasmid at all have been obtained. These variants possess lower virulence for mice infected through enteral and intraperitoneal routes; besides, they lose their capacity for penetration into epithelial cells of HeLa line. S. typhimurium and S. dublin have shown decreased multiplication rate in vivo in comparison with the parent strains, while the multiplication rates in vitro were similar. These results suggest that the products of plasmid genes are either responsible for the virulent properties of salmonellae, or they have regulatory functions, thus controlling the work of chromosomal genes.
authors.forename: O N
authors.initials: ON
authors.lastname: Iakovleva
authors.forename: B I
authors.initials: BI
authors.lastname: Marakusha
mesh_terms: D000818:Animals; D002455:Cell Division; D004269:DNA, Bacterial / Q000235:genetics; D014644:Genetic Variation; D006367:HeLa Cells; D006801:Humans; D007928:Lethal Dose 50; D051379:Mice; D008970:Molecular Weight; D010957:Plasmids; D012475:Salmonella / Q000166:cytology / Q000235:genetics / Q000472:pathogenicity*; D012486:Salmonella typhimurium / Q000166:cytology / Q000235:genetics / Q000472:pathogenicity; D014161:Transduction, Genetic; D014774:Virulence
chemical_list: D004269:DNA, Bacterial
vernacular_title: Biologicheskie svoĭstva besplazmidnykh shtammov Salmonella typhimurium i S. dublin.