title: The effects of radioprotectors on DNA polymerase I-directed repair synthesis and DNA strand breaks in toluene-treated and X-irradiated Escherichia coli.
abstract: In Escherichia coli made permeable to nucleotides by toluene treatment, a DNA polymerase I-directed repair synthesis is induced by exposure to X rays. This repair synthesis may be amplified and easily measured through inhibition of DNA ligase action. In an effort to learn more of the relationship between X-ray-induced strand breaks in cellular DNA and the extent of this repair synthesis, experiments designed to compare the influence of radioprotectors on both strand-break production and repair synthesis have been carried out. The results show that cysteamine, sodium formate, and glycerol not only protect against strand breaks but also reduce DNA polymerase I-directed repair synthesis. However, I-, an efficient hydroxyl radical scavenger, is not as effective a protective agent against strand breaks and does not measurably affect repair synthesis in our system.
mesh_terms: D003543:Cysteamine / Q000494:pharmacology; D004256:DNA Polymerase I / Q000502:physiology*; D004260:DNA Repair / Q000187:drug effects*; D004269:DNA, Bacterial / Q000528:radiation effects*; D004259:DNA-Directed DNA Polymerase / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D004926:Escherichia coli / Q000187:drug effects / Q000528:radiation effects*; D005561:Formates / Q000494:pharmacology; D005990:Glycerol / Q000494:pharmacology; D011193:Potassium Iodide / Q000494:pharmacology; D011837:Radiation-Protective Agents / Q000494:pharmacology*; D013997:Time Factors; D014050:Toluene / Q000494:pharmacology
chemical_list: D004269:DNA, Bacterial; D005561:Formates; D011837:Radiation-Protective Agents; C030544:formic acid; D011193:Potassium Iodide; D014050:Toluene; D003543:Cysteamine; D004256:DNA Polymerase I; D004259:DNA-Directed DNA Polymerase; D005990:Glycerol