rpoS Mutants in Archival Cultures of Salmonella enterica Serovar Typhimurium
AUTOR(ES)
Sutton, Amy
FONTE
American Society for Microbiology
RESUMO
Long-term survival under limited growth conditions presents bacterial populations with unique environmental challenges. The existence of Salmonella enterica serovar Typhimurium cultures undisturbed in sealed nutrient agar stab vials for 34 to 45 years offered a unique opportunity to examine genetic variability under natural conditions. We have initiated a study of genetic changes in these archival cultures. We chose to start with examination of the rpoS gene since, among gram-negative bacteria, many genes needed for survival are regulated by RpoS, the stationary-phase sigma factor. In each of 27 vials examined, cells had the rpoS start codon UUG instead of the expected AUG of Salmonella and Escherichia coli strains recorded in GenBank. Ten of the 27 had additional mutations in the rpoS gene compared with the X77752 wild-type strain currently recorded in GenBank. The rpoS mutations in the 10 strains included two deletions as well as point mutations that altered amino acid sequences substantially. Since these stored strains were derived from ancestral cells inoculated decades ago and remained undisturbed, it is assumed that the 10 rpoS mutations occurred during storage. Since the remaining 17 sequences were wild type (other than in the start codon), it is obvious that rpoS remained relatively stable during decades of sealed storage.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=94605Documentos Relacionados
- Identification of RpoS (ςS)-Regulated Genes in Salmonella enterica Serovar Typhimurium
- Fusidic Acid-Resistant Mutants of Salmonella enterica Serovar Typhimurium with Low Fitness In Vivo Are Defective in RpoS Induction
- DNA Amplification and Rearrangements in Archival Salmonella enterica Serovar Typhimurium LT2 Cultures
- Characterization of the RpoS Status of Clinical Isolates of Salmonella enterica
- Expression of Salmonella typhimurium rpoS and rpoS-dependent genes in the intracellular environment of eukaryotic cells.