Virulence and mutation rates of Salmonella typhimurium strains with increased mutagenic strength in a mouse model.
Two strains of Salmonella typhimurium presenting increased mutation rates, either spontaneous or mediated by DNA damage, have been constructed. One of the strains carries a null mutS mutation, while the other harbors plasmid pRW30, which contains the Escherichia coli umuDC operon. The virulence of these strains has been determined by inoculating BALB/c or Swiss mice. The 50% lethal dose of both strains is identical to that obtained for the wild-type. Likewise, the two strains and the wild-type contribute equally to animal death in mixed infections. The frequency of Nal(R) mutants recovered from animals inoculated with either wild-type or MutS(-) cells was not affected by the presence of pRW30. These results indicate that the DNA damage which S. typhimurium cells can suffer during the infectious process by host cell metabolites does not cause induction of the SOS response at levels able to trigger the error-prone DNA repair pathway.
Campoy
S
S
Department of Genetics and Microbiology, Faculty of Sciences, Universitat Autònoma de Barcelona, Spain.
Pérez de Rozas
A M
AM
Barbé
J
J
Badiola
I
I
D000251:Adenosine Triphosphatases; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics; D004268:DNA-Binding Proteins; D004259:DNA-Directed DNA Polymerase; D004195:Disease Models, Animal; D029968:Escherichia coli Proteins; D005260:Female; D051379:Mice; D008807:Mice, Inbred BALB C; D051719:MutS DNA Mismatch-Binding Protein; D009154:Mutation; D013014:SOS Response, Genetics; D012481:Salmonella Infections, Animal / Q000382:microbiology*; D012486:Salmonella typhimurium / Q000235:genetics* / Q000472:pathogenicity*; D014774:Virulence
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C078202:UmuC protein, E coli; D004259:DNA-Directed DNA Polymerase; C055218:UmuD protein, E coli; D000251:Adenosine Triphosphatases; D051719:MutS DNA Mismatch-Binding Protein; C497175:MutS protein, E coli