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首页> 外文期刊>Journal of bacteriology >Physiological function of superoxide dismutase in glucose-limited chemostat cultures of Escherichia coli.
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Physiological function of superoxide dismutase in glucose-limited chemostat cultures of Escherichia coli.

机译：超氧化物歧化酶在大肠杆菌葡萄糖有限的化学培养物中的生理功能。

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摘要

Conditions for continuous culture of Escherichia coli K-12 His- Thi- under glucose limitation were established. Both the capacity for respiration, at D greater than 0.2/h, and specific activity of superoxide dismutase increased as a function of specific growth rate, whereas peroxidase and catalase were either invariant with or inversely related to this growth rate. The abrupt increase in the availability of glucose, as a means of elevating the growth rate, was followed by an increase in superoxide dismutase, which reached a plateau before there was a significant increase in the growth rate. Thus, an increase in superoxide dismutase appeared to be a prerequisite for an increase in the rate of growth. Cells that had higher levels of superoxide dismutase, because of varying specific growth rates, were more resistant to the toxicity of hyperbaric oxygen. Superoxide dismutase thus behaved like an essential defense against the toxicity of oxygen. Sensitivity towards streptonigrin increased with specific growth rate in the range of 0.09 to 0.25/h but decreased with further increases in the growth rate. Since this antibiotic has been shown to shunt electrons to oxygen, with concomitant production of O2-, these results indicated a progressive deficiency of reducing power at growth rates below 0.25/h and a surfeit of reducing power with progressively greater protection against O2- by superoxide dismutase at growth rates greater than 0.25/h.
机译：建立了大肠杆菌K-12连续培养的条件。建立了葡萄糖限制下的葡萄糖限制。呼吸能力均在大于0.2 / h的d d d的能力和超氧化物歧化酶的特异性活性随着特定生长速率的函数而增加，而过氧化物酶和过氧化氢酶是不变的或与这种生长速率相反。葡萄糖可用性的突然增加，作为提高生长速率的手段，随后是超氧化物歧化酶的增加，该乳化酶达到了高原，然后在生长速率显着增加之前。因此，超氧化物歧化酶的增加似乎是增加生长速率的先决条件。由于特异性生长率不同，具有较高水平的超氧化物歧化酶的细胞对高压氧的毒性更具抗性。过氧化物歧化酶表现得像对氧气毒性的必要防御。腹雪体的敏感性随着0.09至0.25 / h的范围内的特定生长速率而增加，但增长率的进一步增加降低。由于该抗生素已被证明将电子对氧气分流，并且伴随着O 2的产生，这些结果表明，在低于0.25 / h以下的生长率下降低功率的逐渐缺乏，并且通过超氧化物逐渐更大地保护功率的积极性。生长率大于0.25 / h的歧化酶。

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