Department of Microbiology, Macdonald College of McGill University, 21111 Lakeshore Road, Ste. Anne de Bellevue, Québec, Canada H9X 1C0.
Appl Environ Microbiol. 1988 Jun;54(6):1313-7. doi: 10.1128/aem.54.6.1313-1317.1988.
A heterotrophic semisolid medium was used with two sensitive assay methods, C(2)H(2) reduction and O(2)-dependent tritium uptake, to determine nitrogenase and hydrogenase activities, respectively. Organisms known to be positive for both activities showed hydrogenase activity in both the presence and absence of 1% C(2)H(2), and thus, it was possible to test a single culture for both activities. Hydrogen uptake activity was detected for the first time in N(2)-fixing strains of Pseudomonas stutzeri. The method was then applied to the most-probable-number method of counting N(2)-fixing and H(2)-oxidizing bacteria in some natural systems. The numbers of H(2)-oxidizing diazotrophs were considerably higher in soil surrounding nodules of white beans than they were in the other systems tested. This observation is consistent with reports that the rhizosphere may be an important ecological niche for H(2) transformation.
采用异养半固体培养基和两种敏感的测定方法，即 C(2)H(2)还原和 O(2)依赖性氚摄取，分别测定固氮酶和氢化酶活性。已知对这两种活性均为阳性的生物在有和没有 1% C(2)H(2)的情况下均显示出氢化酶活性，因此可以对单个培养物进行这两种活性的测试。首次在固氮假单胞菌的 N(2)固定菌株中检测到氢摄取活性。然后，该方法被应用于一些自然系统中最可能数法计数 N(2)固定和 H(2)氧化细菌的方法。在白豆根瘤周围土壤中，H(2)氧化固氮菌的数量明显高于其他测试系统。这一观察结果与根际可能是 H(2)转化的重要生态位的报告一致。
