OXYGEN TOXICITY AND SUPEROXIDE DISMUTASE
OXYGEN TOXICITY AND SUPEROXIDE DISMUTASE
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DOI：
10.1128/jb.114.3.1193-1197.1973
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发表时间：
1973-01-01
影响因子：
3.2
通讯作者：
FRIDOVICH, I
中科院分区：
文献类型：
--
作者：
GREGORY, EM;FRIDOVICH, I
氧可引起大肠杆菌超氧化物歧化酶含量的增加，但对枯草芽孢杆菌无影响。E.在100%O_2下诱导生长的大肠杆菌B细胞比含有低水平未诱导的这种酶的细胞对20 atm O_2的致死作用有更大的抵抗力。相反，B.枯草芽孢杆菌不能通过增加其超氧化物歧化酶的含量来响应O2，但无论是在100%O2下还是在有氧条件下生长，枯草芽孢杆菌对高压O2都同样敏感。在这些生物体中的过氧化氢酶表现出对氧的相互反应。因此，E. coliB不受O2诱导，而B.枯草杆菌是如此诱导。这些结果是一致的，认为超氧化物歧化酶是防御这些生物体对氧的毒性的重要组成部分，而它们的过氧化氢酶在这方面是次要的。链黑菌素产生O2−的能力，通过一个循环的还原，然后自发再氧化，已在体外得到验证。进一步观察到E.在有氧条件下，超氧化物歧化酶诱导水平高的大肠杆菌B对抗生素的致死性的抗性高于大肠杆菌。大肠杆菌，其中含有低未诱导水平的这种酶。诱导和未诱导的细胞之间的这种差异被消除的O2的去除。这些结果与链黑菌素在需氧条件下增强的致死性可能与其通过还原和自发再氧化循环在体内产生O2−的提议一致。总的来说，这些观察结果支持了O2−是氧毒性的重要因子的假设，并且超氧化物歧化酶的功能是减弱这种活性自由基造成的威胁。
Oxygen caused an increase in the amount of superoxide dismutase inEscherichia coliB but not inBacillus subtilis. E. coliB cells, induced by growth under 100% O2, were much more resistant to the lethal effects of 20 atm of O2than were cells which contained the low uninduced level of this enzyme. In contrast,B. subtilis, which could not respond to O2by increasing its content of superoxide dismutase, remained equally sensitive to hyperbaric O2whether grown under 100% O2or areobically. The catalase in these organisms exhibited a reciprocal response to oxygen. Thus, the catalase ofE. coliB was not induced by O2, whereas that ofB. subtiliswas so induced. These results are consistent with the view that superoxide dismutase is an important component of the defenses of these organisms against the toxicity of oxygen, whereas their catalases are of secondary importance in this respect. The ability of streptonigrin to generate O2−, by a cycle of reduction followed by spontaneous reoxidation, has been verified in vitro. It is further observed thatE. coliB which contain the high induced level of superoxide dismutase were more resistant to the lethality of this antibiotic, in the presence of oxygen, than wereE. coliB which contained the low uninduced level of this enzyme. This difference between induced and uninduced cells was eliminated by the removal of O2. These results are consistent with the proposal that the enhanced lethality of streptonigrin under aerobic conditions may relate to its in vivo generation of O2−by a cycle of reduction and spontaneous reoxidation. In toto, these observations lend support to the hypothesis that O2−is an important agent of oxygen toxicity and that superoxide dismutase functions to blunt the threat posed by this reactive radical.