REACTIVATION OF ULTRAVIOLET-IRRADIATED ESCHERICHIA COLI

Abstract

Survival of cells of E. coli strain B following irradiation with 2537 A UV light is dependent upon the pH of the plating medium. Low pH values, to pH 5.0, increase survival while high pH values, to pH 8.0, decrease the probability of survival. The pH effect is believed to be concerned with recovery of irradiated cells and not with the selection of portions of the population differing in radiation sensitivity. The pH of the medium is specifically critical during the interval of incubation between 2 and 4 hours after irradiation.