The effect of water isotopic composition on Rhodococcus erythropolis biomass production

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...

Possible Mechanisms of Biological Effects Observed in Living Systems during 2H/1H Isotope Fractionation and Deuterium Interactions with Other Biogenic Isotopes

“…Further, the consumption of deuterium-depleted water affects the adaptive capacity of organisms in different periods of ontogeny. It is the choice of the object of research for properly assessing the multifaceted effects of isotope exchange reactions on biological systems that is important in such scientific studies; therefore, in scientific literature, one can find studies of various unicellular and multicellular organisms [74,75,76,77,78], but often in a discrete form, without taking into account the genetic heterogeneity of individuals. However, recently the latter seems to be a relevant factor, because the different sensitivity was shown of animals of different stocks (Wistar and random bred albino male rats) in different periods of ontogeny to the effects of the drinking diet with deuterium-depleted content (δ 2 H = −705‰ [79]), including their morphofunctional indices and biochemical processes (e.g., hydrogen peroxide production by isolated mitochondria of rat liver).…”

Changes in rabbits’ liver morphological parameters in simulation of hypoxia corrected by the use of the modified isotopic D/H composition in the water

“…A determination of deuterium in a blood plasma was done by the NMR spectrometer JEOL JNM-ECA 400 MHz [29,30]. Spectra filming had been done on the appropriate deuterium nucleus resonant frequency -61.4 MHz.…”

Influence of Deuterium-Depleted Water on the Isotope D/H Composition of Liver Tissue and Morphological Development of Rats at Different Periods of Ontogenesis

“…It is very important to make right choice of the purpose of research that would allow to estimate properly the diversity of the effect of isotope exchange reactions produced on biological systems, which seems to be essential in such scientific work. In scientific literature, one can find studies of various unicellular and multicellular organisms [16][17][18] that are often presented in a discrete form, without taking into account the genetic heterogeneity of the studied subjects.…”