Laboratory of Radiation Biology

The unique particle accelerators located at JINR provide the excellent possibilities for a wide spectrum of radiobiological research. This fact has basically defined the fields of cellular and molecular biophysical research at JINR. In 80's the priority of the biological research at JINR was focused on investigation of the mechanisms responsible for the differences in relative biological effectiveness (RBE) of ionizing radiation with different physical characteristics. The RBE problem has been one of the key problems in radiobiology for quite along time. Nevertheless the much efforts p ut in study of RBE problem in radiobiological laboratories of the world, the mechanisms responsible for different relative biological effectiveness of ionizing radiation with different linear energy transfer (LET) have not been revealed. The experiments carried out at JINR heavy ion accelerators have shown the biological effect of radiation with different LET to be basically determined by two main factors: the microdosimetric characteristics of charged particles and the biological properties of the living cells, namely their DNA repair capacity. The RBE problem was solved by the conclusion inferred from experimental and theoretical studies, that the DNA repair ability depends on LET, since the nature of the lethal radiation-induced damages depends on LET

Based on the data on the particularity of the lethal action of different type of radiation on the cells with different genotype, wide research program aimed to thorough investigation of the mutagenic action of radiation with different LET on different bacterial cells was carried out. The linear-quadratic dose-response dependence for mutation induction by gamma-irradiation was found, that does not change with increasing of LET; RBE coefficients of ionizing radiation increase with LET growing and RBE(LET) dependence is described by a curve with a local maximum. The maximum of the dependence for mutagenic assay is shifted in lower region of LET in comparison with that corresponding to a lethal effect of irradiation. The mutation frequency, induced by the radiation with different LET, depends on the state of the cell reparation system. The determining role in mutagenesis play the inducible SOS repair system; the increase of the genetic efficiency of radiation with growing of LET is conditioned by the increase of the multiply DNA damages, repaired by the mutagenic branch of SOS reparation; the gene mutations in prokaryotes induced by heavy charged particles are caused by delta-electron region of the particle track; the difference in the position of the maximum RBE(LET) dependences of the mutagenic and lethal effect of irradiation is conditioned by different nature of the DNA damages. The former are caused by the multiply single strand damages, the latter are caused by the double strand breakes of DNA. The biological effectiveness of the radiation with different LET on the mutagenic assay is determined by the energy micro-distribution in genetic structures, the state of genome and DNA repair system. The role of biological factor in mutagenic efficiency of heavy charged particles also depends on LET.

Radiation-Genetic Studies in Mammalian and Human Cells

study of the mechanisms of stable and unstable chromosome aberration formation in human and mammalian cells exposed to heavy charged particles;

study of mutagenic action of heavy ions on mammalian cells;

study of low dose irradiation effects on chromosome system of mammalian cells;

the comet-method study of the induction and reparation of DNA damages by heavy ions;

Radiation Research

study of radiation field characteristics at the JINR basic installations and in environment; development of accelerators radiation shielding calculation methods;

development of radiation protection system for designing and upgrading accelerators in the JINR and member-states;

study of radiation detectors and dosimeters;

research in the field of radioecology;

physics support of the biological experiments at the JINR basic installations;

Computer Molecular Modeling of Biophysical Systems

modeling of the DNA, RNA, and protein conformation changes; the reparation processes and other related phenomena;

study of the mutation change dynamics;

study of the radiation induced effects;

computer graphical tools and visualizations.

Radiobiological Studies in Retinal and Crystalline of Lens.

mechanism of cataract genesis induced by heavy charged particle;

radiobiological effects of heavy ion irradiation on retina and visual pigment;

study of structure of visual pigment by small-angle scattering of neutrons method.