Ultrafast chemical repair of DNA single and double strand break precursors in irradiated V79 cells
The fast kinetics of reactions of free radical precursors of DNA single strand breaks (ssb) and double strand breaks (dsb) have been determined in Chinese hamster V79 cells by fast mixing and irradiation methods using the alkaline unwinding technique to assay breaks. Fast chemical repair of oxygen-dependent ssb and dsb precursors was observed and approached completion within 10-20 ms of irradiation. Treatment of cells with the glutathione synthesis blocking agent, buthionine sulphoximine, showed that approximately half of the chemical repair was attributable to intracellular non-protein thiols. The nature of the residual repair is obscure, but it is apparently not attributable to non-protein thiols. Similar repair rates and thiol dependences were also found for cell kill. With all three endopoints, oxygen competes with and blocks the chemical repair.
- Research Organization:
- Cancer Research Campaign Gray Laboratory, Middlesex, England
- OSTI ID:
- 5003385
- Journal Information:
- Basic Life Sci.; (United States), Journal Name: Basic Life Sci.; (United States); ISSN BLFSB
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMAL CELLS
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
CHO CELLS
DNA
DNA REPAIR
ELEMENTS
KINETICS
NONMETALS
NUCLEIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
OXYGEN
RADIOINDUCTION
REACTION KINETICS
RECOVERY
REPAIR
STRAND BREAKS
THIOLS