title: Conditional transduction of Salmonella typhimurium envB mutations.
abstract: Joint transduction of the argR and envB genes was observed, at a frequency of 24.5%, when four envB strains were transduced to tetracycline resistance (Tetr) with bacteriophage P22 grown on an argR372::Tn10 envB+ donor. When round-cell argR372::Tn10 derivatives of those envB strains were used as donors, two of them did not produce envB transductants in wild-type LT2 and other envB+ recipients, even though large numbers of Tetr transductants were obtained. This apparent exclusion of envB mutations did not occur when mecillinam-resistant derivatives of those envB+ strains were used as recipients. Mutations conferring partial resistance to mecillinam were found, unlinked to the argR-envB region, in three of the four envB strains studied; envB+ derivatives of the four strains were competent to accept envB mutations excluded by wild-type recipients. It is suggested that some envB mutations are lethal in the absence of suppressor mutations, some of which increase resistance to mecillinam.
mesh_terms: D000560:Amdinocillin / Q000494:pharmacology; D005798:Genes, Bacterial; D009154:Mutation; D010403:Penicillin Resistance; D012486:Salmonella typhimurium / Q000166:cytology / Q000187:drug effects / Q000235:genetics*; D014161:Transduction, Genetic
chemical_list: D000560:Amdinocillin