Further studies on a temperature‐sensitive mutant of Escherichia coli with defective repair capacity

Abstract

A temperature-sensitive mutant of E. coli, WG24, was studied with respect to its sensitivity to photodynamic action, its capacity to perform host controlled reactivation, and its sensitivity to transduction a t elevated temperatures. Mutant cells are much more sensitive than wild type cells to photodynamic action by thiopyronine and visible light a t elevated temperatures. As well defined rec mutants, WG24 cells are less able to reactivate UV irradiated I c phages a t elevated temperatures, while their ability to repair T1 phages is less impaired. Mutant cells cannot be transduced t o T6 resistance a t a detectable rate a t elevated temperature. It is concluded, therefore, that some rec gene carries a ts mutation in this mutant.