Chromosomal mutagenesis in human somatic cells: 30-year cytogenetic monitoring after Chornobyl accident.

In the lecture we have generalized and analyzed the data of cytogenetic laboratory of National Research Center for Radiation Medicine of the National Academy of Medical Sciences of Ukraine on 30-year selective cytogenetic monitoring among the priority contingents of different ages exposed to radiation after Chornobyl accident in Ukraine. It is highlighted that not only targeted but also untargeted radiation-induced cytogenetic effects should be explored, especially in delayed terms following radiation exposure. The new methodical approaches for studying "bystander effect", individual radiosensitivity, and various forms of radiation-induced chromosomal instability (delayed, hidden, transmissible) have been proposed.

[Radiation induced modification of human somatic cells chromosome sensitivity in testing mutagenic effect of bleomycin].

The voluntary investigation of hidden chromosome instability in 53 persons with different intensity of radiation exposure had been carried pout using modified "G2-bleomycin sensitivity assay". In all examined groups the individual levels of chromosome injuries under identical bleomycin exposure varied in wide range and didnrt depend on their initial values in the intact cultures. Among control donors and individuals with low radiation exposure approximately 33% hypersensitive persons had been identified that can be considered as genetically caused phenomenon.

[Chromosome instability revealed in children of fathers irradiated during Chernobyl accident].

Four children groups with and without thyroid pathology born to fathers exposed to ionizing irradiation in 1986 during Chernobyl accident as liquidators as well as residents of territory with radioactive contamination have been cytogenetically observed. The frequency and spectrum of chromosome aberrations in peripheral blood lymphocytes have been studied using two-termed cultivation (during 48 and 144 hours). Under the short-term incubation the observed groups did not significantly differ on the mean-group integral cytogenetic parameters which corresponded to age norm, but in progeny of parents from radionuclide contaminated territory the increased level of chromosome type exchanges has been revealed.

[Results of a cytogenetic study of children from radionuclide-contaminated goiter endemic zone of the Rivno region of Ukraine ].

Under the conventional cytogenetical examination of 6 different children groups (with and without non-stohastic thyroid pathology, exposed and nonexposed to the iodine isotopes in 1986) from the goiter endemic zone of Ukraine which belongs to the territory contaminated by 137Cs radionuclides, the identical to the spontaneous level of somatic chromosome mutagenesis of the last decade in all observed groups with the tendency to increasing of stable aberrations in some persons had been established.

[The results of 14-year cytogenetic monitoring of priority follow-up groups of Chernobyl accident victims].

The paper presents the results of 14-year (1987-2000) random cytogenetic monitoring of the Ukraine's population exposed to radiation due to the Chernobyl Atomic Power Plant accident. Conventional, G-banding, and molecular (FISH-WCP) cytogenetic methods were used to examine groups of victims exposed to radiation of varying intensity (reconvalescents diagnosed as having acute radiation disease, liquidators, Chernobyl power plant staff, and persons who had lived in the radionuclide-polluted areas, etc.).

[Dimatif modification of the cytogenetic effect in the peripheral blood lymphocytes of children subjected to a constant low-intensity radiation exposure].

Primary results of cytogenetic monitoring of children living in regions of Ukraine contaminated after Chernobyl accident permit suggesting existence of radiation-induced modification of sensitivity of somatic cell chromosomes to mutagens. It may be supposed that interindividual and group difference in sensitivity of in vivo irradiated cells to additional induction of in vitro mutagen effect is explained not only by inherited properties, but also by preliminary irradiation.

[Thiosulfate oxidation by nonsulfur purple bacteria].

The capability to oxidize thiosulfate was studied in 11 cultures of purple bacteria belonging to Rhodomicrobium vannielii, Rhodopseudmonas viridis, Rh. sphaeroides, Rh. capsulata, and Rhodospirillum rubrum.

[Ectothiorhodospira shaposhnikovii respiration when growing in light and in darkness].

The respiration of the purple phototrophic bacterium Ectothiorhodospira shaposhnikovii grown in the light under the anaerobic conditions or in the dark in the presence of oxygen is stimulated with sulfide, NNNN-tetramethyl-p-phenylenediamine (TMPD) + ascorbate and, to a less extent, organic substrates. The electron transport system of the organism is characterized by weak activities of NADH- and NADPH-oxidoreductases and a weak activity of the oxidase region. The respiration of intact cells in the presence of various substrates and the activity of enzymes of the respiration chain in E.

[Thiosulfate metabolism in Rhodopseudomonas palustris].

The cells of the purple nonsulfur bacterium Rhodopseudomonas palustris, Nakamura strain, are capable of oxidizing thiosulfate and sulfide both under the anaerobic conditions in the light and under the aerobic conditions in the dark. Regardless of the presence of thiosulfate in the medium, the cells contain thiosulfate reductase, rodanase, thiosulfate oxidase, and sulfite oxidase. However, the capability to oxidize thiosulfate and sulfide is induced in Rh.

[Growth of purple sulfur bacteria in the dark in anaerobic conditions].

Phototrophic sulphur bacteria Chromatium minutissimum 1 C, Ectothiorhodospira shaposhnikovii 1, and various strains of Thiocapsa roseopersicina grow in the dark under anaerobic conditions (hydrogen or argon) on organic media in the presence of sulphide, thiosulphate or molecular sulphur. Ect. shaposhnikovii grows also in the presence of sulphite, cysteine, methionine, glutathione, and, to a less degree, sulphates.