title: Loss of R factors promoted by bacteriophage M13 and the M13 carrier state.
abstract: The infection of different Hfr strains of Escherichia coli bearing derepressed R factors of the fi(+) or fi(-) type can result in the loss of the R factor and the conversion of the infected cells to the R(-) state. This extends earlier observations on the elimination of F' factors by bacteriophage M13 infection. Variability in the efficiency of this conversion can arise because of genetic factors independent of the R factor being eliminated. A fraction of the infected but unconverted R(+) cells were M13 carrier strains. The carrier state had an intracellular basis, and single R(+) cells could maintain the carrier state.
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D003090:Coliphages / Q000254:growth & development*; D003227:Conjugation, Genetic; D004352:Drug Resistance, Microbial; D004926:Escherichia coli / Q000187:drug effects*; D005111:Extrachromosomal Inheritance; D007106:Immune Sera / Q000494:pharmacology; D007612:Kanamycin / Q000494:pharmacology; D009154:Mutation; D013381:Subtilisins / Q000494:pharmacology; D013752:Tetracycline / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D007106:Immune Sera; D007612:Kanamycin; D013381:Subtilisins; D013752:Tetracycline