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Relative rates of repair of single-strand breaks and postirradiation DNA degradation in normal and induced cells of Escherichia coli. [uv radiation]

Journal Article · · Biophys. J.; (United States)
Labeled DNA from irradiated Escherichia coli cells was studied on an alkaline sucrose gradient without acid precipitation of the DNA. This enabled the observation of both DNA repair and DNA degradation. The use of a predose of ultraviolet light (uv) caused induction of an inhibitor of postirradiation DNA degradation in le lambda/sup +/ strains. The effect of this induction on both the repair of single-strand breaks and DNA degradation was followed in strains WU3610 (uvr/sup +/) and WU3610-89 (uvr/sup -/). The repair process was more rapid than the degradation, and when degradation was inhibited more repair was apparent. Cells that were lex/sup -/ (B/sub s-1/ and AB2474) could not be induced for inhibition of degradation. Nevertheless, by observation at short times repair could be seen clearly. This repaired DNA was degraded, suggesting that the signal for DNA degradation is not a single-strand break.
Research Organization:
Pennsylvania State Univ., University Park
OSTI ID:
6203816
Journal Information:
Biophys. J.; (United States), Journal Name: Biophys. J.; (United States) Vol. 24:2; ISSN BIOJA
Country of Publication:
United States
Language:
English