Radiation biology. Radioecology
ISSN: 0869-8031

Archives → 2020 → V. 60. №6. → pp. 595–603

Article

Study of the Mechanism of Dioxidine Genotoxicity using lux-Biosensors of Escherichia coli

D. A. Sviridova, E. A. Machigov, E. V. Igonina, B. S. Zhoshibekova, S. K. Abilev

N.I. Vavilov Institute of General Genetics, Russian Academy of Sciences, Moscow, Russia

Abstract

We studied the ability of the antibacterial agent dioxidine to generate superoxide anion radicals in E. coli cells, induce an SOS response, cause DNA fragmentation, bacterial death, and the effect of antioxidants on these processes using E. coli luminescent biosensors. Dioxidine induced the SOS response in the pColD-lux biosensor at concentrations in which it most effectively induces luminescence in the pSoxS-lux biosensor, which responds to an increase in the superoxide concentration in the cell. Dioxidine in concentrations of more than 0.001 mol/L caused a decrease in the survival of bacterial cells and, as revealed by electrophoretic analysis, is accompanied by degradation of bacterial DNA. Recalculation of quantitative indicators of the luminescence intensity of pColD-lux per 1000 viable cells showed that the level of the biosensor SOS response from the concentration of dioxidine does not decrease, but increases. The antioxidants glutathione and acetylcysteine in bacterial cells reduced the induction by dioxidine of both the SOS response and the increase in the level of superoxide radical. DNA degradation increased with increasing dioxidine concentration and decreased with the combined use of dioxidine and antioxidants. The probable mechanisms of the formation of a hydroxyl radical during the reduction of the dioxidine NO group by bacterial reductases are discussed.

Keywords

dioxidine, biosensors, Esherichia coli, SOS response, free radicals, electrophoresis, DNA degradation, bacterial survival, antioxidants