文章基本信息

标题：Strand Break Formation in Plasmid DNA Irradiated in Aqueous Solution: Effect of Medium Temperature and Hydroxyl Radical Scavenger Concentration.
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作者：HIROYUKI TOMITA ; MICHIAKI KAI ; TOMOKO KUSAMA 等
期刊名称：Journal of Radiation Research
印刷版ISSN：0449-3060
电子版ISSN：1349-9157
出版年度：1995
卷号：36
期号：1
页码：46-55
DOI：10.1269/jrr.36.46
摘要：Plasmid pBR322 DNA (4363 base pairs) in aerobic aqueous solution was irradiated with 60 Co γ-radiation. The change of diffusion coefficients ( D ) of chemical species, rate constants ( k ) of radical-DNA interaction and solubilities of O 2 in water cannot be ignored when a temperature varies more than a few tens of centigrade. It is important to examine the variation of the yields of DNA strand breaks as a function of temperature in order to analyze the mechanisms of DNA strand breaks from the chemical point of view. Hence, we observed the change of the yield of strand breaks with temperatures between -20 and 42°C by agarose gel electrophoresis. We also observed the change of the yield of strand breaks with the concentration of OH scavenger (Tris) from 1 mmol dm -3 to 100 mmol dm -3 and summarized it with previous experiments. This summarization indicated that the order of the lifetime of OH radical in cellular environment is several nanosecond. This value is consistent with the measurement of the lifetime of 8.7 nanosecond for OH radical in mammalian cell (Roots, R. and Okada, S. (1975) Radiat. Res. 64, 306-320).
关键词：plasmid DNA; strand break; aqueous solution; temperature; lifetime of hydroxyl radical