Ultraviolet inactivation and photoproducts of transforming DNA irradiated at low temperatures.
Solutions of Haemophilus influenzae transforming DNA were irradiated at temperatures ranging from 25 degrees C to - 196 degrees C. Temperature dependence of the formation of thymine-containing dimers was closely correlated with inactivation of transforming activity; in general, both dimerization and inactivation decreased with decreasing temperature. The fraction of nonphotoreactivable damage increased with increasing dose at low temperatures. The nonphotoreactivable spore-type photoproduct was formed at low temperatures with a maximum at - 100 degrees C, a temperature at which the nonphotoreactivable biological inactivation was also a maximum. Intrastrand cross-linking, like dimer formation, decreased with decreasing irradiation temperature.
D002854:Chromatography, Paper; D003080:Cold Temperature; D004269:DNA, Bacterial / Q000528:radiation effects*; D006193:Haemophilus influenzae; D008027:Light; D011830:Radiation Effects; D013941:Thymine; D014170:Transformation, Genetic; D014466:Ultraviolet Rays
D004269:DNA, Bacterial; D013941:Thymine