Hassan H M, Fridovich I
J Bacteriol. 1977 Mar;129(3):1574-83. doi: 10.1128/jb.129.3.1574-1583.1977.
Anaerobically grown Escherichia coli K-12 contain only one superoxide dismutase and that is the iron-containing isozyme found in the periplasmic space. Exposure to oxygen caused the induction of a manganese-containing superoxide dismutase and of another, previously undescribed, superoxide dismutase, as well as of catalase and peroxidase. These inductions differed in their responsiveness towards oxygen. Thus the very low levels of oxygen present in deep, static, aerobic cultures were enough for nearly maximal induction of the manganese-superoxide dismutase. In contrast, induction of the new superoxide dismutase, catalase, and peroxidase required the much higher levels of oxygen achieved in vigorously agitated aerobic cultures. Anaerobically grown cells showed a much greater oxygen enhancement of the lethality of streptonigrin than did aerobically grown cells, in accord with the proposal that streptonigrin can serve as an intracellular source of superoxide. Anaerobically grown cells in which enzyme inductions were prevented by puromycin were damaged by exposure to air. This damage was evidenced both as a decline in viable cell count and as structural abnormalities evident under an electron microscope.
厌氧培养的大肠杆菌K - 12仅含有一种超氧化物歧化酶，即存在于周质空间的含铁同工酶。暴露于氧气会诱导产生含锰超氧化物歧化酶、另一种先前未描述的超氧化物歧化酶、过氧化氢酶和过氧化物酶。这些诱导作用对氧气的反应性有所不同。因此，深层静止需氧培养物中存在的极低水平氧气足以使锰超氧化物歧化酶的诱导作用接近最大值。相比之下，新的超氧化物歧化酶、过氧化氢酶和过氧化物酶的诱导需要在剧烈搅拌的需氧培养物中达到的更高水平的氧气。与链黑菌素可作为细胞内超氧化物来源的提议一致，厌氧培养的细胞比需氧培养的细胞对链黑菌素致死性的氧气增强作用要大得多。用嘌呤霉素阻止酶诱导的厌氧培养细胞暴露于空气中会受到损伤。这种损伤表现为活细胞计数下降以及在电子显微镜下可见的结构异常。
