Radiation-induced damage in Escherichia coli B: the effect of superoxide radicals and molecular oxygen.
Radiation-induced damage in Escherichia coli B: the effect of superoxide radicals and molecular oxygen.
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大肠杆菌 B 中的辐射引起的损伤：超氧自由基和分子氧的作用。
DOI：
10.2307/3574810
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发表时间：
1978
影响因子：
3.4
通讯作者：
G. Czapski
中科院分区：
文献类型：
--
作者：
A. Samuni;G. Czapski
研究了超氧自由基和分子氧在悬浮于稀磷酸盐缓冲液中的大肠杆菌B的辐射损伤中的作用。在γ辐射的细胞悬浮液中存在高浓度的聚乙二醇对细菌的辐射敏感性没有影响。这表明损伤主要是内源性的，即起源于细胞内。用N₂O使细胞悬浮液饱和使辐射敏感性加倍，因此表明OH自由基是造成大部分损伤（间接辐射效应）的原因。在有或没有N₂O的情况下存在氧气都会使辐射敏感性大约增加三倍。由于在有N₂O的情况下，所有的eₐq⁻都被一氧化二氮而不是氧气清除，这表明超氧自由基在细菌辐射损伤中没有作用。我们的结果证实了氧效应归因于O₂与重要生物分子上被OH损伤的位点的直接相互作用，并排除了eₐq⁻和O₂⁻对细胞辐射损伤的任何显著贡献。
The roles of superoxide radicals and of molecular oxygen in the radiodamage of Escherichia coli B suspended in dilute phosphate buffer were studied. The presence of high concentrations of polyethylene glycol in the ..gamma..-irradiated cell suspensions had no effect on bacterial radiosensitivity. This indicated that the damage was primarily endogenous, i.e., originated intracellularly. Saturation of the cell suspensions with N/sub 2/O doubled the radiosensitivity, thus indicating that OH radicals were responsible for the majority of the damage (indirect radiation effect). The presence of oxygen either in the absence or presence of N/sub 2/O brought about roughly a threefold increase in the radiosensitivity. Since in the presence of N/sub 2/O all e/sub aq//sup -/ were scavenged by the nitrous oxide rather than by oxygen, this shows that superoxide radicals played no role in the bacterial radiodamage. Our results substantiate the attribution of the oxygen effect to a direct interaction of O/sub 2/ with the OH-damaged sites on vital biomolecules and exclude any significant contribution of e/sub aq$/sup -/ and O/sub 2//sup -/ to the cellular radiodamage.