DARK REACTIVATION IN ULTRAVIOLET IRRADIATED ESCHERICHIA COLI

Abstract

UV-irradiated cells of E. coli B were reactivated in the dark while suspended in physiological saline solution. Although the magnitude of dark reactivation approached that obtained by photorecovery, the time required to reach this level was about 14 hours with dark incubation as compared to 50 minutes with light. Temperature influences the rate of recovery, giving optimum results at 35oC for 100 minutes of reactivation. The effects of photoreactivation and dark reactivation are not additive. An UV resistant strain of E. coli. C-30, showed little ability to be dark reactivated.