Genomic integrity of T1 DNA after gamma-and ultraviolet irradiation.
T1 DNA, gamma-irradiated in the phage particle or irradiated with ultraviolet light was checked for structural integrity by kinetics of melting and reannealing. gamma-Irradiated DNA differed in all thermokinetic properties by a factor of 3-4 from DNA degraded by mechanical or enzymatical treatments. Ultraviolet irradiation caused much smaller effects than gamma-irradiation. Considering the frequency of pyrimidine dimers in relation to the gamma-ray induced lesions, strong evidence can be derived, that in addition to single base damages, local denatured regions are produced by gamma-irradiation. Such regions, formed possibly by direct absorption of radiation energy in DNA, i.e. by primary ionizations, are associated with base lesions and are passed over during reannealing.
D003090:Coliphages; D004277:DNA, Single-Stranded; D004279:DNA, Viral / Q000528:radiation effects*; D004926:Escherichia coli; D005720:Gamma Rays; D007700:Kinetics; D008433:Mathematics; D009691:Nucleic Acid Denaturation; D009695:Nucleic Acid Renaturation; D014466:Ultraviolet Rays
D004277:DNA, Single-Stranded; D004279:DNA, Viral