Determination of the Substrates for Sulphate-reducing Bacteria within Marine and Esturaine Sediments with Different Rates of Sulphate Reduction
Determination of the Substrates for Sulphate-reducing Bacteria within Marine and Esturaine Sediments with Different Rates of Sulphate Reduction
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不同硫酸盐还原率的海洋和河口沉积物中硫酸盐还原菌底物的测定
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发表时间：
1989
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通讯作者：
R. Herbert
中科院分区：
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作者：
R. Parkes;G. Gibson;I. Mueller;W. Buckingham;R. Herbert
通过用 20 mM 钼酸盐选择性抑制硫酸盐还原并测量由此产生的底物积累，确定了来自 Loch Eil、Loch Etive 和 Tay 河口的沉积泥浆中硫酸盐还原细菌使用的底物。添加钼酸盐后，底物积累呈线性，积累速率与硫酸盐还原速率密切匹配，表明除专门涉及硫酸盐还原的代谢途径外，其他代谢途径不受抑制剂影响。在所有三个地点的沉积物中，乙酸盐都是主要底物，尽管由于乙酸盐氧化而减少的硫酸盐百分比在各个地点之间差异很大（泰河口，35％；Loch Eil，64％；Loch Etive，100％）。除醋酸盐外，在泰河口和 Loch Eil 沉积物中，17 种单独的底物被证明在不同程度上参与了硫酸盐还原；这些包括乳酸盐、H2、丙酸盐、异丁酸盐和正丁酸盐、异戊酸盐和正戊酸盐、2-甲基丁酸盐和氨基酸。在这两个地点，丙酸盐占硫酸盐减少量的 6% 至 12%。丁酸盐（正丁酸和异丁酸）、异戊酸和 2-甲基丁酸在每个地点的重要性大致相同，合计分别占泰河口和 Loch Eil 沉积物硫酸盐减少量的 13% 和 11%。乳酸仅在泰河口沉积物中很重要，占硫酸盐减少量的 43%。泰河口沉积物中氨基酸积累率最大，但艾尔湖中氨基酸对硫酸盐还原的贡献（9%）高于泰河口沉积物（2%）。在测量的 21 种氨基酸中，有 9 种呈线性增加；其中最重要的是丝氨酸、谷氨酸和精氨酸。一般来说，当硫酸盐还原率较高时，该过程的底物比较低时更加多样化。结合两个实验的结果并假设各个底物完全降解，几乎所有硫酸盐减少都可以在每个地点进行（泰河口，101％；Loch Eil，98％；Loch Etive，> 100％）。
The substrates used by sulphate-reducing bacteria in sediment slurries from Loch Eil, Loch Etive and the Tay estuary were determined by selectively inhibiting sulphate reduction with 20 mM-molybdate and measuring the resultant substrate accumulation. Substrate accumulation was linear after molybdate addition, and the rate of accumulation closely matched sulphate reduction rates, indicating that metabolic pathways other than those specifically involving sulphate reduction were not affected by the inhibitor. In sediments from all three sites acetate was a major substrate, although the percentage of sulphate reduced due to acetate oxidation varied considerably among the sites (Tay estuary, 35%; Loch Eil, 64%; Loch Etive, 100%). In addition to acctate, 17 individual substrates were shown to be involved in sulphate reduction to varying extents in the Tay estuary and Loch Eil sediments; these included lactate, H2, propionate, iso- and n-butyrate, iso- and n-valerate, 2-methylbutyrate and amino acids. At both sites propionate accounted for between 6 and 12% of sulphate reduction. Butyrate (n- and iso-), iso-valerate and 2-methylbutyrate were of approximately equal importance at each site and together accounted for 13 and 11%, respectively, of the sulphate reduction in the Tay estuary and Loch Eil sediments. Lactate was only importnat in the Tay estuary sediments, where it accounted for 43% of sulphate reduction. The rate of accumulation of amino acids was greatest in the Tay estuary sediments, but the contribution of amino acids to sulphate reduction was higher in the Loch Eil (9%) than in the Tay estuary sediments (2%). Of the 21 individual amino acids that were measured there was a linear increase in nine; the most important of these were serine, glutamate and arginine. In general, when sulphate reduction rates were high the substrates for this process were more varied than when rates were low. Combining the results of two experiments and assuming complete degradation of the individual substrates, almost all the sulphate reduction could be accounted for at each site (Tay estuary, 101%; Loch Eil, 98%; Loch Etive, > 100%).