title: Lethal effects of pyrimidine dimers induced at 365 nm in strains of E. coli differing in repair capability.
abstract: Photoreactivation (PR) after 365-nm inactivation was measured in four strains of Escherichia coli differing in repair capability. Photoreactivation was observed in the recA strains K12 AB2480 and K12 AB2463 indicating a significant role of pyrimidine dimers in the lethal action of 365-nm radiation in these strains. Significant PR was not observed in the uvrA strain, K12 AB1886, or in the repair proficient strain, K12 AB1157, after 365-nm inactivation. Biological evidence indicated that stationary phase cells had not lost the capacity for photo-enzymatic repair after fluences of 365-nm radiation of 2 X 10(6) J/m-2 or less. It is proposed that pyrimidine dimers, although induced, are not significant 365-nm lethal lesions in uvrA and wild-type strains because of their efficient dark repair.
mesh_terms: D004260:DNA Repair; D004255:Deoxyribodipyrimidine Photo-Lyase / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology / Q000528:radiation effects*; D008027:Light; D011740:Pyrimidine Dimers
chemical_list: D011740:Pyrimidine Dimers; D004255:Deoxyribodipyrimidine Photo-Lyase