The incubation in deuterium-depleted medium of mitochondria isolated from the liver of rats that consumed drinking diet with depleted deuterium (46 ppm) revealed a higher (by 35%) generation of hydrogen peroxide in comparison with the mitochondria (isolated from the liver of rats that consumed drinking diet with 152 ppm deuterium) incubated in medium that contained 152 ppm deuterium. Succinate addition to the reaction system led to an increase in the production of hydrogen peroxide in isolated mitochondria by 44-81%, whereas the difference in the generation of HO between the organelles incubated in mediums 46 and 152 ppm was reduced by 14%. The revealed change in the functional activity of mitochondria suggests the ability of the organism to adapt to the deuterium-depleted drinking diet, which is probably due to the formation of the D/H isotope transmembrane gradient.

No abstract

The effect of the physical and chemical properties of a medium on the functioning of biological systems is today attracting the close attention of researchers. Broadening the problem area in this field is related to many unsettled questions appeared upon analysis of the results of mild exposures of living matter of differ ent levels of organization. Isotopic composition of water is one of the most important physical and chem ical factors, the significance of which is doubtless [1,2]. It has been found that the biological effects could be observed upon small natural variations in the isoto pic composition of water both toward a decrease and increase with respect to the standard ocean water [2]. As a result of numerous studies of the effect of water with increased deuterium content on biological sys tems, different positive and negative dose and object dependent effects have been observed [1,[3][4][5][6].At present, research on the biological effects of water with decreased deuterium content has consider ably progressed. Investigations performed on different living organisms [6-9] have revealed predominantly positive effects. However, as in the case of heavy water, the effects were dose dependent [3, 10, 11], the choice of a bioobject being of great significance.The study of mechanisms of the effect of isotopic composition of water on the functioning of biological systems demonstrated their intricacy and diversity. Suggestions regarding the effect of deuterium on sys tems of hydrogen bonds providing the structure and functions of macromolecules were made. It was noted that hydrogen bonds with deuterium involved are sev eral times stronger than the conventional ones. Upon cell incubation in water with a changed D/H ratio, when compared to the initial one, not only the ratio of deuterium and protium water as a solvent within the biological system changed, but also isotopic exchange in hydroxyl, sulfhydryl, carboxyl, and amino groups of molecules of all the organic compounds occurred [1,[12][13][14].In connection with the growing number of studies of the biological effects of light water, investigation of the effect of such media on bacteria, including rhodo cocci, is of interest. This group of microorganisms is evolutionarily adapted to utilization and transforma tion of a wide range of compounds of hydrocarbon ori gin. Natural compounds utilized by actinobacteria including representatives of the Rhodococcus genus are petroleum hydrocarbons entering the biosphere in a natural and technogenic way and other natural biolog ically stable compounds including hydrophobic ones. The main habitat of actinobacteria is soils, humic and other organic compounds of which serve as an almost exhaustless carbon depot available for maintenance of the vital functions of this group of bacteria. To follow the ecological K strategy typical for rhodococci, they have a corresponding catabolic enzymatic apparatus and system of energy efficient transport of hydrocar bon molecules into the cell represented by the produc tion of biogenic surfac...

Rhodococcus strains with a wide spectrum of catabolic genes, have provided a more marked reduction of toxicity of imidazolinone. In the case of glyphosate, the opposite strain-specific pattern is found.

No abstract