Suter W, Rosselet A, Knüsel F
Antimicrob Agents Chemother. 1978 May;13(5):770-83. doi: 10.1128/AAC.13.5.770.
The effect of quindoxin on the synthesis of deoxyribonucleic acid (DNA), ribonucleic acid, and protein in Escherichia coli KL 399 was examined under aerobic and anaerobic conditions. In the absence of oxygen the synthesis of DNA was completely inhibited by 10 ppm of quindoxin, whereas the syntheses of ribonucleic acid and protein were not affected. Quinoxalin-di-N-oxides (QdNO) induce degradation of DNA in both proliferating and non-proliferating cells. polA, recA, recB, recC, exrA, and uvrA mutants were more susceptible than the corresponding repair-proficient strains. All strains were more resistant in the presence of oxygen. Quindoxin was reduced to quinoxalin-N-oxide by intact E. coli cells or by a cell-free E. coli extract. Electron spin resonance measurements demonstrated the generation of free radicals during the reduction of quindoxin. Oxygen or deficiency of energy sources impaired the antibiotic activity and the reduction of QdNO. The QdNO reductase activity was demonstrated to be lower in QdNO-resistant mutants than in the susceptible parent strain. Based on these results it is concluded that an intermediate of reduction, probably a free radical, is responsible for the lethal effect of quindoxin. With three independent techniques no evidence has been found for binding of quindoxin to DNA.
在需氧和厌氧条件下，研究了喹乙醇对大肠杆菌KL 399中脱氧核糖核酸（DNA）、核糖核酸和蛋白质合成的影响。在无氧条件下，10 ppm的喹乙醇可完全抑制DNA的合成，而核糖核酸和蛋白质的合成不受影响。喹恶啉二-N-氧化物（QdNO）可诱导增殖细胞和非增殖细胞中的DNA降解。polA、recA、recB、recC、exrA和uvrA突变体比相应的修复 proficient 菌株更敏感。在有氧条件下，所有菌株的抗性都更强。完整的大肠杆菌细胞或无细胞的大肠杆菌提取物可将喹乙醇还原为喹恶啉-N-氧化物。电子自旋共振测量表明，喹乙醇还原过程中会产生自由基。氧气或能量源缺乏会损害抗生素活性和QdNO的还原。已证明QdNO抗性突变体中的QdNO还原酶活性低于敏感亲本菌株。基于这些结果得出结论，还原中间体，可能是自由基，是喹乙醇致死作用的原因。通过三种独立技术，未发现喹乙醇与DNA结合的证据。
