[Corn plant DNA methylation pattern changes upon fractional UV-C irradiation].

Relationship of changes of methylation pattern of functionally different parts of DNA and chromosomal aberration yield was studied at the conditions of the fractionating of UV-C irradiation. Combination of restriction analysis (Hpall, MspI, MboI enzymes) with the subsequent raising of PCR (internal transcribed space ITS1, 1TS4 and inter simple sequence repeat - ISSR, 14b primers) was used. The got results testify to the changes in methylation pattern of satellite and transcription active part of DNA atan irradiation in the mode of fractionating and depending on fraction time ranges. The role of the methylation DNA pattern change in development of radiation damage and induction of organism protective reactions was discussed.

[Fractionated UV-C irradiation effects on the changes of transcribed and satellite DNA methylation profile and unstable chromosomal aberration yield].

Interaction between changes of functionally different DNA methylation pattern and chromosomal aberration yield under fractionated UV-C exposure at the doses-of 6.2-9 kJ/m2 have been investigated. Two ways of meristematic tissue renewal after irradiation have been revealed on the grounds of statistical analysis. To estimate changes in the methylation pattern of transcribed and satellite DNA the restriction analysis was carried out. The restriction reaction was followed by PCR with ITS1(19b), ITS4(20b) and ISSR(14b) primers. The obtained data indicate specific changes in the methylation pattern of transcribed and satellite DNA parts under fractionated irradiation with different fraction ranges. Possible role of these changes in the progressing irradiation damage and inducible protection reactions is discussed.

[Structural architectonics of apical root meristems in coherence with the quantitative assessment of its damage by radiation].

The dose dependencies of the aberrant anaphases frequency in the root meristem in 48 hours after irradiation in the range of doses of 4-10 Gy is characterized by threshold and plateau at 33% aberrant anaphase. The plateau indicates the activation of the recovery processes. Topology of cell rows in the primary meristem of the dose to 8 Gy are conserved and recovered damages. New cell rows are formed by local cell pools in the distal meristem, pericycle cells and subepidermy. It grows by intrusive character displacing the rows of damaged cells. Apparently the competition between clones of normal and aberrant cells plays the primary role in the mechanisms of recovery. Resulting to competition the promotion of aberrant cells to the extension zone is slowed down or blocked. So critical level of damage of the root apical meristem was defined about 50% of aberrant anaphase. Exceeding of this level leads to lethal consequence for meristem and it is accompanied by the inclusion of more radical process of restoration through regeneration. Regeneration leads to complete replacement of the apex tissues including the extension zone.

[Critical level of radiation damage of root apical meristem and mechanisms for its recovery in Pisum sativum L].

The dose dependencies of growth and cytogenetical values have been built to determine the critical level of root apical meristem damage induced by cute irradiation in the range from 2 to 20 Gr. We have analyzed the frequencies of aberrant anaphases and the aberration distribution per cell, on the one hand, and the growth of biomass, the survival and regeneration of the root meristem, on the other hand. The critical level of damage to the stem apical meristem and root of seedlings was defined as 44-48% of aberrant anaphase. Exceeding of this level leads to the launch of suicidal program through induction of multiaberrant damages and interphase cell death. It appears that competition of clones of non-aberrant cells, the cells bearing 1 and 2 damages and multiaberrant cells plays the primary role in the mechanisms of recovery. The regeneration provides full or partial restoration of the main root apical meristem. However these local processes are insufficient to restore morphogenesis and survival of seedlings in excess of the critical level damage.

[Changes in wheat DNA methylation pattern after chronic seed gamma-irradiation].

Alterations of DNA methylation patterns of wheat two varieties--Odessa' albatross and Donetsk 48 have been studied. Seeds were irradiated for 4 months with low dose rate (3 x 10(-7) Gy/s). Six restriction endonucleases were used in the experiments. Primary distinction in DNA methylation patterns of the studied varieties has been demonstrated. The chronic irradiation resulted in the increase of methylation level on the sites of recognition for Glul and Sou3Al and in the decline of this index for the sites of recognition of GlaI and HpaII. The meaningful increase of chromosome aberration levels was demonstrated at the same accumulated dose of chronic irradiation. The role of changes of DNA methylation patterns in development of radiation damage and organism protective reactions is discussed.

[The dynamics of cytogenetic anomalies output in seedling merysteme at the chronic irradiation of seeds].

The dynamics of chromosomal aberrations in seedling root merysteme is explored in various terms of irradiation of two genotype corn dry seeds. The effects of chronic irradiation with low rate dose, with acute and with combined irradiation are explored in the different terms of seed storage. It is shown that the output of chromosomal aberrations and of the efficiency of irradiation (1/Gy) change depending on the accumulated dose of chronic irradiation and for both genotypes are described by unmonotonous functions. Efficiency of acute irradiation changes the dependence on the terms of seed storage. The efficiency of chronic irradiation considerably exceeds the efficiency of acute irradiation. Antagonistic effect of combined irradiation dry seeds of one of genotypes is marked.

[Regeneration mechanisms of ontogenetic radioadaptation in plants].

Experimental data were obtained that in pea seedlings modified by decapitation of main root had increased radioresistance (radioadaptation), fixed by various parameters of growth activity of lateral roots, and decreased ability to repair sublethal damages, detected by method of acute gamma-irradiation dose fractionation. These facts both with enlargement of dose dependence shoulder in lateral roots of decapitated seedlings led to conclusion that main role in such mechanism of radioadaptation effect of decapitation belongs to supercellular processes such as repopulation and regeneration. Conclusion was confirmed by the additional comparative investigations of cyto- and histological parameters of apical meristems of intact (control) and decapitated (experiment) lateral roots. It was shown, that the decapitated seedlings had increased mitotic activity of apical meristems of lateral roots and total volume of their meristematic zone. So at the moment of application of irradiation in the test-dose decapitated variant had significantly more meristematic cells of certain size that allowed biological object to form necessary (critical) amount of elements for valid or more complete postradiation recovery.

[The influence of UV-B radiation on reproductive function of Hordeum vulgare L. plants].

It has been shown that ultraviolet-B radiation induced acceleration of flowering and differentiation of sexual spike elements in barley. Increasing of pollen asynchronous development and variability of pollen grains with growing of pollen grain sterility were observed as well. The productivity of plants irradiated with UV-B radiation did not change. Considerable doses of irradiation resulted in decreasing of pollen sterility by intensification of haplontic cell selection. The influence of UV-B radiation on the plants can be considered as a genotoxical effects via formation of initial cell DNA damages and photoinduction.

[Chronic low doze ionizing irradiation and polyfactors of adaptation].

The analysis of cytogenetic anomaly dynamics in conditions of chronic low doze effect of ionizing irradiation in generations of genetically homogeneous laboratory line of mice CC57W/Mv and genetically heterogeneous populations of vole's species, trapped in alienation zone of Chernobyl's NPP in places with different levels of radio nuclide contamination in 1994-2001 was carried out. The data about the physiological adaptation to ionizing irradiation effects under age of linear mice and non-linearity of frequency changes of separate cytogenetic anomalies in generations as laboratory line of mice, and genetically heterogeneous populations of vole's species were obtained. Was supposed, that the number of non-linear effects of the ionizing irradiation in low doze range could be stipulated by comparability between the intensity of it's damage effects and the activation by it the polyfactor systems of anti oxidant ones, reparation events, and also elimination of defective cells.

[Radiation injury of the plants in the zone of influence of the accident on Chernobyl Nuclear Power Station (NPS)].

Were considered the radiobiological effects in some species of agricultural and wild growing plants in 30-kilometer zone of alienation of Chernobyl nuclear power station and other radionuclide contaminated territories. The particular attention was given to the distance plant reactions: immunity decreasing, genetic consequences, changes in phytocenosis. Was discussed the question of possibility of plant adaptation to conditions of high radiation influence.

[Molecular and cellular aspects of development of arbuscular mycorrhizal symbiosis and its role in plant life]. / Molekuliarnye i kletochnye aspekti razvitiia arbuskuliarnykh mikoriznykh simbiozov i ikh znachenie v zhiznedeiatel'nosti rastenii.

Development of arbuscular mycorrhizal (AM) symbiosis with plant root system in term of molecular and cellular events have been analysed. A role of AM symbiosis in plant life has been discussed. Molecular methods for analysis of arbuscular mycorrhizal fungi have been described.

[Effects of chronic irradiation on the adaptive potential of plants]. / Vliianie khronicheskogo oblucheniia na adaptivnyi potentsial rastenii.

The content of anthocianins was determined in Oenothera biennis plants, grown from seeds, picked on the plots with different levels of radionuclide contamination in the 30-km Chernobyl zone. It was shown that the content of anthocianins was higher in plants from Yanov area (20-40 mR/h) than in plants from Chernobyl area (0.04 mR/h). An acute gamma-irradiation of seeds with a dose of 5-100 Gy or UV-irradiation of plants resulted in increasing of anthocianin content which was higher in plants grown from the seeds picked on plots with a low level of radionuclide contamination. The data obtained suggest that chronic irradiation of O. biennis populations induces accumulation of anthocianins. Apparently the adaptivity potential has been more completely realised in plants on the plots with a higher level of radionuclide contamination. The populations which were formed in the absence or at the low level of radionuclide contamination, on the contrary, have a significant adaptivity potential and, accordingly, higher radioresistance.

[Cytogenetic effects of 241Am in the Allium test]. / Tsitogeneticheskie éffekty 241 Am v Allium-teste.

The purpose of this study was to elucidate the genome damage induced by 241Am-irradiation using different parameters of cytogenetic evaluation in Allium-test. The root tip cells test-system for the cytogenetic effects studying was used. 241AmCl3 of different concentrations was used (1.5 x 10(-9)-1.5 x 10(-7) g/l). Water solution-to-plant transfer factor for 241Am was found to be 0.18 +/- 0.04. The internal doses of 241Am accumulated during germination were 0.37-37.00 cGy. The impact of 241Am-irradiation was evaluated on the mitotic index (MI), the yield of aberrant anaphases (AA), the distribution of chromosome aberrations number in cells and the average level of lesion of aberrant cell (LAC). Probably all these parameters are differ in sensitivity to damage factor, but only some changes in MI was revealed. It is supposed, that the absence of any changes in the distribution of chromosome aberrations number in cells and the average level of LAC in 241Am-irradiated cells confirm the absence of significant 241Am-impact on chromosomes, as the alpha-irradiation should cause significant damages in chromosomes. Although solutions of 241Am were high-concentrated, the seedlings didn't accumulate high internal doses. It appears the distribution of 241Am is a significantly heterogeneous hence it is possible the absorbed doses in nuclei can't reach the level necessary for revealing of cytogenetic effects.

[Radiation-induced changes in the genome of pine seeds, forming under conditions of chronic irradiation in the Chernobyl exclusion zone]. / Radiatsionno-indutsirovannye izmeneniia v genome semian sosny, sformirovabshikhsiia v usloviiakh khronicheskogo oblucheniia v zone otchuzhdeniia ChAES.

Comparative study of long-term existing genome damages in the chronically irradiated pine seeds from different parts of Chernobyl zone have been performed by a pulsed field gel electrophoresis and hydroxyapatite chromatography. Some differences were established for DNA degradation kinetic from protoplasts with various accumulated doses of irradiation. Results obtained could testify the existence of long-living changes in the experimental plants genome.

[Soil-plant linkage and expected doses in humans from incorporated long-lived radionuclides]. / Zveno "pochva--rastenie" i ozhidaemye dozovye nagruzki na cheloveka ot inkorporirovannykh dolgozhivushchikh radionuklidov.

The algorithm for calculation of the expected received dose resulted from intake of long-lived 137Cs and 90Sr radionuclides accepted with food has been proposed. The contamination rate and agrochemical type of soils which were involved into trophical chain formation were considered in evaluation of radionuclide level in diet. The calculation of dose loading was made for seven main types of soil in Ukrainian wooded district.

[Antimitotic compounds as modifiers of the radiation lesion of cultured cells]. / Antimitoticheskie soedineniia kak modifikatory luchevogo porazheniia kul'tiviruemykh kletok.

The features of antimitotic substances as radioprotectors were studied. In vitro experiments have demonstrated that taxol revealed radioprotective features concerning the process of polymerization of irradiated microtubules. These results were the basis for the use of taxol and some other substances with high affinity for cytoskeleton proteins as potential radiomodificators in vivo. Experiments with cultivated fibroblasts revealed that colchicine significantly enhances radioactive injuries of cells while taxol and phalloidin manifest their radioprotective features.

[Genetic disorders in the pollen cells of waxy barley in radioactive contamination after the Chernobyl accident]. / Geneticheskie narusheniia v pyl'tsevykh kletkah iachmenia waxy v usloviiakh radioaktivnykh zagriaznenii posle Chernobyl'skoi avarii.

Genotoxic effects during microsporogenesis and gametogenesis were studied in barley of the waxy strain grown on 3 experimental plots situated in the region of the Chernobyl disaster (plot 1 in the town of Chernobyl, plots 2 and 3 in the town of Yanov, 3 km away from the damaged power plant). It was determined that an increased level of radionuclide pollution and chronic irradiation during ontogenesis results in higher incidence of meiotic disturbances and abnormalities during formation of the male gametophyte. Incidence of waxy reversions in pollen grains depends on the activity of radionuclide pollutants as well. We suggest that selection affecting both diplont and haplont forms will provide for the absence of significant aberrations in subsequent plant generations.

[Statistical criterium of pollution heterogeneity in the research of biotic factors of radionuclides migration]. / Statisticheskii kriterii geterogennosti zagriazneniia pri issledovanii bioticheskikh faktorov migratsii radionuklidov.

The nature of the radionuclide contamination resulting from Chernobyl disaster is in its spatial and aggregate heterogeneity determined by the interaction of systematic and incidental factors. To study the radionuclide migration in the soil-plant system, an independent statistical index of contamination heterogeneity H = RAsAp is proposed which is calculated as a Brave-Pirsens coefficient of linear correlation between radioactivity of soil and dry biomass of plants grown on it and which allows to determine relative range of contamination that appears in the form of "hot particles". An adequacy of this index is substantiated, and it is used to analyze the experimental results on radionuclide migration.

[A morphogenetic analysis of a callus culture of Nicotiana tabacum L. in chronic irradiation of the plants]. / Morfogeneticheskii analiz kallusnoi kul'tury Nicotiana tabacum L. pri khronicheskom obluchenii rastenii.

The callus culture of Nicotiana tabacum L. was obtained from the plants chronically irradiated in 10 km zone of Chernobyl Atomic Power Station. The tobacco plants in 10 km zone of Chernobyl during the vegetation period exposed to irradiation with the average dose rate of 0.36 mA/kg (5 mP/h). The total absorbed dose was approximately 0,31 Gy. The morphogenetic analysis of this culture shows a considerable decrease of regeneration index and callus weight.