The toxic effect of strained hydrocarbon 2,2'—bis (bicyclo[2.2.1]heptane) (BBH) was studied using whole-cell bacterial lux-biosensors based on Escherichia coli cells in which luciferase genes are transcriptionally fused with stress-inducible promoters. It was shown that BBH has the genotoxic effect causing bacterial SOS response however no alkylating effect has been revealed. In addition to DNA damage, there is an oxidative effect causing the response of OxyR/S and SoxR/S regulons. The most sensitive to BBH lux-biosensor was E . coli pSoxS-lux which reacts to the appearance of superoxide anion radicals in the cell. It is assumed that the oxidation of BBH leads to the generation of reactive oxygen species, which provide the main contribution to the genotoxicity of this substance.

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Discharges in He-CO, He-CO-O2 mixtures are studied in the range of experimental parameters typical of the action of a high-power CO laser with fast gas flow and liquid N2 cooling. Gas and vibrational temperatures, their radial profiles, CO vibrational population and E/N values are measured. The values of E/N are also calculated by solving the electron balance equation. Comparison of the measured and calculated data shows that the dominant ionization process in He-CO mixtures is the reaction CO+e to CO++2e. For He-CO-O2 mixtures, the reaction CO( nu >14)+CO*(I1 Sigma ) to C2O2++e is proposed as the main ionization process. Such a mechanism allows one to explain the marked influence of a small O2 admixture on He-CO plasma parameters.

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Toxic effect of 2-ethylnorbornane (2-ethyl(bicyclo[2.2.1]heptane) (EBH)) on bacteria has been studied using the E. coli pRecA-lux and E. coli pKatG- lux cells as lux-biosensors. It was shown that the addition of EBH to the incubation medium leads to death and growth retardation, high level oxidative stress and DNA damage in E. coli cells. It is assumed that the oxidation of EBH with atmospheric oxygen causes the formation of reactive oxygen species in the medium, which makes a major contribution to the toxicity of this substance. biosensor, luciferase, bioluminescence, inducible promoter, PrecA, PkatG The authors are grateful to Stanislav Filippovich Chalkin for the development of interdisciplinary ties in the scientific community. The work was financially supported by the Ministry of Higher Education and Science of Russia (Project Unique Identifier RFMEFI60417X0181, Agreement No. 14.604.21.0181 of 26.09.2017).