Method for the isolation of Escherichia coli relaxed mutants, utilizing near ultraviolet irradiation

Abstract

Near ultraviolet radiation (300 to 380 nm) induces a transient growth inhibition in 'stringent' (rel+) strains of E. coli, whereas 'relaxed' +) strains of E. coli, whereas 'relaxed(rel-) strains are only mildly affected. This difference permits rapid isolation of large numbers of relaxed mutants of E. coli.