[Nuclear spin catalysis in nanoreactors of living cells].

There is a great variety of chemical elements with magnetic and nonmagnetic isotopes in living cells. The question arises as to whether living cells can perceive the difference between magnetic and non-magnetic isotopes of chemical elements. It has been shown that bacteria Escherichia coli, which were previously enriched with the magnetic isotope of magnesium, 25Mg, essentially faster adapt to the new growth media in comparison with the cells, which were enriched with the nonmagnetic isotopes, 24Mg or 26Mg.

[Reliability of electron-transport membranes and the role of oxygen anion-radicals in aging: stochastic modulation of the genetic program].

All biomolecular constructions and nanorecators are designed to perform preset functions. All of them operate with limited reliability, namely, for each and every device or bionanoreactor normal operation alternates with accidental malfunctions (failures). Timely preventive maintenance replacement (prophylaxis) of functional elements in cells and tissues, the so-called turnover, is the main line of assuring high system reliability of organism as a whole.

[The radioecological problem of radon].

Radon and its daughter decay products are the main part of natural radiation background. The review presents the information on indoor radon radiation level, radon sources, exposure doses and effects on human health. In addition to radioecological aspects, the radon effects should be considered as the important problem of low-dose radiation biology.

[The modelling of survival and mortality curves for human populations based on the theory of reliability].

The reliability theory model of aging (Kol'tover 1981, 1982) was used for analysis of life-tables of Swedish males and females for 1951-1955, 1962-1973 and 1971-1975 calendar years. In terms of the model it has been possible 1) to explain the Gompertz "law" of mortality; 2) to describe quantitatively statistical life-table data including Gompertz's and geriatric ages; 3) to predict the behavior of mortality rate function depending on the extent of population heterogeneity, among them the existence, at respective degrees of heterogeneity, of a maximum in geriatric age range and 4) to estimate the species-specific maximum life-span potential of animals.

[Interconnection between activity and conformational mobility of alpha-chymotrypsin in reverse micelle systems].

A comparative study of the catalytic activity of alpha-chymotrypsin and the spin label rotation frequency in the alpha-chymotrypsin active center of reverse micellar systems solvated by H2O-organic mixtures was carried out. It was found that the decrease in the label rotation frequency resulting from the substitution of water in the micellar inner cavity by glycerol, 2.3-butanediol and dimethylsulfoxide (up to 95%) caused a marked increase (20-fold in the case of 2.

[Structural state of the cardiomyocyte sarcolemma in animals of different ages].

Cardiomyocyte plasmalemma membranes of adult (12 months) and old (24-26 months) rats have been studied. Ageing is accompanied with an essential decrease of the content of the membrane protein SH-groups. We have found an increase in the fraction of strongly immobilized spin-labeled SH-groups, a decrease in that of unsaturated lipids, as well as an increase in that of lysophosphatidylcholine in old rats membranes.

[Stimulation of transcription in mouse liver cells by nitrogen oxide free radicals].

The ESR signal of nitrosyl complexes appears in mouse liver after hydroxylamine injection in vivo. This ESR signal testifies to the appearance of NO free radicals. The concomitant accumulation of [3H]uridine in liver RNA evidences for stimulation of transcription.

[Effect of enterosorption on EPR signals in the liver of rats of different ages].

Liver EPR signals were studied in adult (8 months) and old (24 months) Wistar male rats after the 30 days course of enterosorption carried out daily. The signals were analyzed at the values of g = 1.94, 2.

[Effect of the antioxidant dibunol on the electron paramagnetic resonance signals in the tissues of rats of different ages].

Changes in the intensity of EPR signals from the skeletal and heart muscles, liver, kidneys, thyroid, adrenal cortex, and blood were studied in relation to the animals age and the effect of the antioxidant dibunol. Essential changes were revealed in metabolic activity of the majority of the tissues under study as early as within the first 6 hours after antioxidant administration.

Permeability of bilayer lipid membranes for superoxide (O2-.) radicals.

Egg yolk phosphatidylcholine monolamellar liposomes (1000 A in diameter) loaded with cytochrome c were placed into an external solution, in which superoxide radicals, O2-., were generated by a xanthine-xanthine oxidase system. The penetration of the superoxide radicals across the liposomal membrane was detected by cytochrome c reduction in the inner liposome compartment.

[Permeability of bilayer phospholipid membranes to superoxide oxygen radicals].

Lecithin monolayer liposomes (1000 A in diameter) loaded with cytochrome c were placed into the external solution, in which O2 superoxide radicals were regenerated by the xanthine-xanthine oxidase system. The penetration of superoxide radicals across the liposomal membranes was followed by cytochrome c reduction in the interval volume of the liposomes. The effects of lipid membrane modifiers and temperature on this process were investigated.

[Structural characteristics of paramagnetic analogs of enzyme-substrate complexes of phosphorylation coupling factors].

Mn2+-ion is linked to isolated chloroplast coupling factor CF-1 via the ATP bridge in the catalytically competent ternary complex as deduced from water proton relaxation rate measurements. Two essential SH-groups in CF-1 protein were modified with nitroxyl mercuric derivative as spin label. The substrate complex Ca2+-ATP is shown to induce the structural transition near the active site to the state with a stronger immobilized spin label.

[Reliability of enzyme systems and molecular mechanisms of aging].

A stochastic model of animal mortality and ageing is proposed. In a living being there is a "biological clock", constructed from Q kinds of functional elements (genes), The reliability of functioning of these genes determines the biological age of the being. Oxidative processes in the cells are accompanied by random failures of electron transfer enzyme systems, which result in appearance of free superoxide radicals.