молекулярная биофизика, биофизика клетки, физико-химические механизмы регуляции, механизмы влияния ЭМП
Prof. Sergei Aksyonov is a Head of Exobiology Laboratory of Biophysical Department of Biological Faculty of Lomonosov Moscow State University. He has graduated from Physical Faculty of MSU as physicist and after having worked in the Lebedev Physical Institute of USSR Acad. Sci. He received his Candidate of Phys.-Mathem. degree in Physical Institute (1963) (speciality experimental physics). Since 1965 till now he has been working in the Biological Faculty of MSU, where received his Doctor of Phys.-Mathem. degree (1979) (speciality biophysics). Subject of his dissertation was "State of water and its role in dynamics of biological structures". Aksyonov published more than 220 papers on the molecular and membrane biophysics, experimental physics, exobiology, plant physiology, microbiology. He published 2 monographs and was a supervisor of 15 Candidate theses.
Aksyonov proposed a concept on the regulative action of water in biological structures. He elaborated also a concept on dynamic character of stability of biological systems with different levels of organization. Sensitivity to regulation as a condition of reproduction, not strength of structures, has a key significance in durability. The dynamic character of stability is also an inherent property of DNA, that leads to the impossibility of immortality of individual organisms - their death occurs usually because of weakening the immune system and, on the contrary, the active immune system, in the long run, "devour" the organism. Necessity of preventing general pandemia requires variability in amino acid composition of proteins in different types of organisms, thus variability can not be regarded as "neutral".
Aksyonov revised previous estimations of water state in biological systems which were made by different physical methods, and obtained a new correct estimation. Generalized characteristics of dynamics of proteins in water and data on their differences between 12 enzyme and non-enzyme proteins were obtained. Effects of competition of water for inter-chain hydrogen bonds were shown on model ethyleneimine polymers. Complicated character of dynamics of biological-active substances in membranes has been demonstrated. Study of three species of photosynthetic membranes and model systems revealed four different stages of hydration. Each of them is associated with specific changes in the structure, dynamics and electron transfer efficiency in number of steps of photosynthetic chain. Sensitive mechanism of regulation of cellular metabolism at the expense of protein sorbtion-desorbtion process was proposed, that because of changes in dynamics of proteins and entropy leads to small change in free energy. The differences between regulative action of Ca and Mg ions and the nature of sensitivity of cellular metabolism to the small changes of pH, hydration level and other weak exposures were explained on the basis of this mechanism. The causes of increase of relaxation times for water protons in serum under cancer were elucidated. On basis of NMR and EPR-imaging data the heterogeneity of distribution and the state of water within endosperm of wheat seed during imbibition and maturation was shown. In exobiology the work on the limits of active functioning of biological systems in extreme conditions, on the duration limits of anabiosis, on the specificity of biological role of water, on the capability for regulation of water relations for lower plants in high mountain deserts have been done. The critical analysis of Viking data on the search of life in Mars was fulfilled and so on.
Аксенов С. И., Грунина Т. Ю., Горячев С. Н.Физико-химический механизм влияния магнитных бурь и ЭМП низких частот на биологические и социальные процессы // Биомедицинская радиоэлектроника, 2007. № 8-9, с.77-87
A mathematical modelling of the K+/H+ antiport system was carried out to investigate the influence of a weak low-frequency applied periodic electric field on ion flux via a carrier across the lipid membrane. Nonlinear in character, the system can have a damped oscillatory, trigger or self-sustained oscillatory behaviour depending on the pattern of the ionic flux. Numerical calculation showed that the applied electric field could parametrically regulate nonlinear biological systems and the effects can be significant in bifurcation areas. The intensity of applied periodic electric field was estimated to be in the range 10-600 V/cm and the frequency in the range 10-2-10 Hz.
Smirnov A. I., Aksyonov S. I., et alIn vivo seed investigation by electron paramagnetic resonance spin probe technique // J. Plant Physiology, 1992, 140:447-452
Aksyonov S. I., et alC and P spectroscopic study of dynamics vs function relations in photosynthetic membranes of purple bacteria at different humidity // Biologicheskye membrany, 1991, 8:491-503
Aksyonov S. I., et alESR tomography of water state in wheat seeds at early ripening stage // Biofizika, 1991, 36:318-321
Aksyonov S. I.Dynamic character of stability of biological systems and effect of water on it // Studia biophysica, 1990, 136:117-132
Aksyonov S. I., et alEffect of low-molecular ligands on relaxation of water protons in protein solutions // Biofizika, 1990, 35:39-42
Smirnov A. I., Aksyonov S. I., et alEPR-tomography study of distribution of water-dissolved probe in wheat grain during imbibition // Fiziologiya rastenii, 1988, 35:663-668
Aksyonov S. I., Golovina E. A.Admission and distribution of water in wheat seeds during swelling // Soviet Plant Physiology, 1986, 33:124-130
Aksyonov S. I., et alEffect of hydration of Rhodospirillum rubrum photosynthetic membrane and reaction centre protein preparations on their functional activity // Izvestiya AN SSSR, biolog. serie, 1985, N 1:105-116