Plugge Caroline M, Jiang Bo, de Bok Frank A M, Tsai Chingling, Stams Alfons J M
Laboratory of Microbiology, Wageningen University, Dreijenplein 10, 6703 HB, Wageningen, The Netherlands.
Arch Microbiol. 2009 Jan;191(1):55-61. doi: 10.1007/s00203-008-0428-9. Epub 2008 Sep 16.
The effect of tungsten (W) and molybdenum (Mo) on the growth of Syntrophobacter fumaroxidans and Methanospirillum hungatei was studied in syntrophic cultures and the pure cultures of both the organisms. Cells that were grown syntropically were separated by Percoll density centrifugation. Measurement of hydrogenase and formate dehydrogenase levels in cell extracts of syntrophically grown cells correlated with the methane formation rates in the co-cultures. The effect of W and Mo on the activity of formate dehydrogenase was considerable in both the organisms, whereas hydrogenase activity remained relatively constant. Depletion of tungsten and/or molybdenum, however, did not affect the growth of the pure culture of S. fumaroxidans on propionate plus fumarate significantly, although the specific activities of hydrogenase and especially formate dehydrogenase were influenced by the absence of Mo and W. This indicates that the organism has a low W or Mo requirement under these conditions. Growth of M. hungatei on either formate or H2/CO2 required tungsten, and molybdenum could replace tungsten to some extent. Our results suggest a more prominent role for H2 as electron carrier in the syntrophic conversion of propionate, when the essential trace metals W and Mo for the functioning of formate dehydrogenase are depleted.
在共养培养物以及两种微生物的纯培养物中，研究了钨（W）和钼（Mo）对富马酸氧化互营杆菌（Syntrophobacter fumaroxidans）和亨氏甲烷螺菌（Methanospirillum hungatei）生长的影响。通过Percoll密度离心法分离共养生长的细胞。对共养生长细胞的细胞提取物中氢化酶和甲酸脱氢酶水平的测量与共培养物中的甲烷生成速率相关。W和Mo对两种微生物中甲酸脱氢酶活性的影响相当大，而氢化酶活性保持相对恒定。然而，钨和/或钼的耗尽对富马酸氧化互营杆菌在丙酸盐加富马酸盐上的纯培养物生长没有显著影响，尽管氢化酶尤其是甲酸脱氢酶的比活性受Mo和W缺失的影响。这表明该生物体在这些条件下对W或Mo的需求较低。亨氏甲烷螺菌在甲酸或H2/CO2上生长需要钨，钼在一定程度上可以替代钨。我们的结果表明，当甲酸脱氢酶功能所需的必需微量金属W和Mo耗尽时，H2作为电子载体在丙酸盐的共养转化中发挥更突出的作用。
