Subject(s)
Cyclophosphamide/analogs & derivatives , Microsomes, Liver/metabolism , Animals , Antineoplastic Agents/pharmacology , Chemical Phenomena , Chemistry , Cyclophosphamide/metabolism , Cyclophosphamide/pharmacology , Mice , Nitro Compounds , Phenylhydrazines/analogs & derivatives , Rats , WaterSubject(s)
Monoamine Oxidase/metabolism , Phenylhydrazines/metabolism , Animals , Carbon Radioisotopes , Electrophoresis, Polyacrylamide Gel , In Vitro Techniques , Mitochondria, Liver/enzymology , Monoamine Oxidase/analysis , Phenylhydrazines/analogs & derivatives , Protein Binding , Rats , Sodium Dodecyl Sulfate , Time FactorsSubject(s)
2,3-Diketogulonic Acid/blood , Ascorbic Acid/analogs & derivatives , Dehydroascorbic Acid/blood , Diabetes Mellitus/blood , Sugar Acids/blood , Ascorbic Acid/blood , Colorimetry , Female , Homocysteine , Humans , Light , Male , Methylene Blue , Nitro Compounds , Phenylhydrazines/analogs & derivativesABSTRACT
The degradation of DNA in a repair-proficient strain (B/r) and in two repair-defective strains (Bs-1 and pol A) of Escherichia coli was studied in the presence and absence of three metabolic inhibitors after exposure of the cells to X-radiation. The radiation-induced degradation of DNA was dependent on energy production in freshly harvested log-phase cells and was closely related to the repair capacity of the cells. A different system, probably involving nonspecific deoxyribonucleases acting at radiation-induced strand breaks, appeared to be responsible for the degradative processes in stationary-phase cells or in log-phase cells which had been aged by standing in buffered saline for 2 days before irradiation. The three inhibitors tested (caffeine, rifampin, and carbonyl cyanide m-chlorophenyl hydrazone) were all found to inhibit partially the radiation-induced degradation of DNA in E. coli cells. Under other conditions, the same three compounds amplified the degradative process. The data suggested that the amplification was due to a selective inhibition of repair processes. The degradative processes which were stimulated by X-radiation of E. coli cells show many parallels to those which are evoked by phleomycin or colicine.