Enhancement of Damage to Escherichia coli Strain B/R after Ultraviolet and Irradiation

SUMMARY: Death of Escherichia coli after exposure to ultraviolet (u.v.) radiation or to γ-rays was markedly increased when the bacteria were incubated on media containing chloramphenicol or puromycin. A similar effect occurred when an irradiated histidine-requiring strain of E. coli b/r was deprived of its requirement but not when several other amino acid auxotrophic mutants of E. coli b/r were similarly deprived. The extra killing may be associated with the synthesis of RNA rather than be a direct consequence of inhibition of protein synthesis.