The Application of Rapid Lysis Techniques in Radiobiology: III. The Effect of Radiosensitizers on the Production of DNA Damage and the Time Course of Its Repair

Abstract

FIELDEN, E. M., SAPORA, 0., AND LOVEROCK, P. S. The Application of Rapid Lysis Techniques in Radiobiology. III. The Effect of Radiosensitizers on the Production of DNA Damage and the Time Course of Its Repair. Radiat. Res. 75, 54-65 (1978). Para-nitroacetophenone (PNAP) increases the yield of single-strand breaks (ssb) measured 0.2 sec after irradiation of Escherichia coli B/r to the same extent as does oxygen. Norpseudopelletierine-N-oxyl (NPPN) does not modify the yield of ssb seen. By studying the time course of the enzymatic repair of ssb and DNA with E. coli B/r and K12 Pol Al it was shown that neither PNAP or NPPN enhanced the yield of fixed damage of the type produced by oxygen. Repair of radiation-produced ssb in the NPPN experiments was inhibited so that after -120 sec the yield of ssb was the same as was found with PNAP or 02. It was concluded that PNAP can only mimic one of the effects of oxygen on DNA damage and that NPPN modifies DNA damage in a different manner to oxygen.