EFFECTS OF NON‐IONIZING AND IONIZING RADIATIONS ON THE TRANSFORMING ABILITY OF E. COLI DNA

Abstract— A transformation system in Escherichia coli was employed to verify the extent of the lesions caused by ultraviolet (UV) and ionizing radiations. DNA inactivated at 280 nm could be reactivated to some extent by exposing the transforming DNA solutions at 240 nm. This reactivation has been tested using more than one strain of E. coli as recipient. Transforming DNA inactivated by ionizing radiations (90Sr beta rays and 60Co gamma rays) was not reactivable. Low doses of beta rays, however, reactivated the DNA inactivated by 280 nm UV to a slight but significant extent.