Loss of R Factors Promoted by Bacteriophage M13 and the M13 Carrier State

摘要

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.