%A"Bresler, S E" %A"Noskin, L A" %A"Suslov, A V [AN SSSR, Leningrad. Inst. Yadernoj Fiziki]" %D1980 %I; %2 %J[] %K63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT., DNA, BIOLOGICAL RADIATION EFFECTS, STRAND BREAKS, BIOLOGICAL REPAIR, RADIOINDUCTION, DOSE-RESPONSE RELATIONSHIPS, ELASTICITY, ESCHERICHIA COLI, GAMMA RADIATION, VISCOSIMETERS, BACTERIA, BIOLOGICAL EFFECTS, BIOLOGICAL RECOVERY, ELECTROMAGNETIC RADIATION, IONIZING RADIATIONS, MEASURING INSTRUMENTS, MECHANICAL PROPERTIES, MICROORGANISMS, NUCLEIC ACIDS, ORGANIC COMPOUNDS, RADIATION EFFECTS, RADIATIONS, RECOVERY, REPAIR, TENSILE PROPERTIES, 560131* - Radiation Effects on Microorganisms- Basic Studies- (-1987) %PMedium: X; Size: Pages: 1289-1300 %TInduction of double-strand breaks in DNA of prokaryotes and eukaryotes and their repair. 1. Application of elastoviscosimetry for studying double-strand breaks in DNA of Escherichia coli induced by. gamma. -irradiation %XIt is shown that the method of elastoviscosimetry gives a possibility to record the formation of DNA double-strand breaks in Escherichia coli cells induced by ..gamma.. irradiation at doses close to D/sub 37/. The dependence of changes of elastoviscosity parameter on the dose (tau/sub 0/) passes through the maximum. It is shown that the ascending section of this curve (at minimum ..gamma.. irradiation doses) characterizes the relaxation process of the superspiralised chromosome in nucleotide of the E. coli. This relaxation is observed due to ..gamma.. induced damages which are not double-strand breaks. By the maximum position one can judge on a dose yield of the first DNA double-strand break, the descending part of the dose curve describes the kinetics of accumulation of breaks with the dose increase. The analysis of the data obtained gives the possibility to come to the conclusion that when applying a usual technique of irradiation and lysis of cells not providing for special measures on inhibition of endo-and exonuclease activity in ..gamma.. irradiated cells, the dose yield of double-strand breaks noticeably increases (by 4.2 times). In the case of an essential, though incomplete, inhibition of nuclease activities in ..gamma.. irradiated cells the dose yield of breaks approximately corresponds to the dose curve of inactivation of these cells (D/sub 37/12.5+-3.0 krad, the first double-strand break -at 14.5+-2.4 krad). %0Journal Article %N;Journal ID: CODEN: MOBIB %1 %CUSSR %Rhttps://doi.org/ Journal ID: CODEN: MOBIB HEDB %GRussian