Hill S, Turner G L, Bergersen F J
J Gen Microbiol. 1984 May;130(5):1061-7. doi: 10.1099/00221287-130-5-1061.
Effects of very low concentrations of dissolved O2 on nitrogenase activity in Klebsiella pneumoniae were studied in a stirred chamber system which enabled simultaneous measurements of steady-state O2 concentrations, O2 consumption and C2H2 reduction. A strain carrying a chromosomal nifH::lac fusion as well as the Nif+ plasmid pRD1, expressed nitrogenase activity with 80 nM-O2, a concentration known to inhibit nifH::lac expression by about 50% Thus nitrogenase activity in vivo was no more sensitive to O2 than expression of nifH::lac. When compared with anaerobic treatments, dissolved O2 near 30 nM apparently stimulated nitrogenase derepression and enhanced the activity of nitrogenase synthesized anaerobically. Thus, in this organism, N2 fixation occurs in microaerobic as well as anaerobic conditions.
在一个搅拌室系统中研究了极低浓度溶解氧对肺炎克雷伯菌中固氮酶活性的影响，该系统能够同时测量稳态氧浓度、氧消耗和乙炔还原。携带染色体nifH::lac融合基因以及Nif+质粒pRD1的菌株，在80 nM - O₂浓度下表达固氮酶活性，已知该浓度可抑制nifH::lac表达约50%。因此，体内固氮酶活性对氧的敏感性并不比nifH::lac的表达更高。与厌氧处理相比，接近30 nM的溶解氧明显刺激了固氮酶的去阻遏，并增强了厌氧合成的固氮酶的活性。因此，在这种生物体中，固氮作用在微需氧和厌氧条件下均会发生。
