The relation of resistance transfer factors to the F-factor (sex-factor) of<i>Escherichia coli</i>K12

Abstract

The genetic elements promoting conjugation associated with transmissible drug resistance are of two or more kinds. Experiments with phage specific for F + bacteria have shown that one large class differs from F essentially only in the production of a cytoplasmic repressor which limits the synthesis of the specific F pilus, whether by the RTF itself or by F when this is present in the same cell.