Department of Biochemistry, Faculty of Biology and Environmental Protection, University of Silesia, Katowice, Poland.
PLoS One. 2013;8(1):e53484. doi: 10.1371/journal.pone.0053484. Epub 2013 Jan 9.
Electron transport chain (ETCh) of ammonium (AOB) and nitrite oxidizing bacteria (NOB) participates in oxidation of ammonium to nitrate (nitrification). Operation of ETCh may be perturbed by a range of water-soluble xenobiotics. Therefore, consortia of nitrifying bacteria may be used as a biosensor to detect water contamination. A surprising feature of this system is an increase of oxygen consumption, detected in the presence of certain inhibitors of ETCh. Thus, to shed light on the mechanism of this effect (and other differences between inhibitors) we monitored separately respiration of the bacteria of the first (AOB - Nitrosomonas) and second (NOB -Nitrobacter) stages of nitrification. Furthermore, we measured plasma membrane potential and the level of reduction of NAD(P)H. We propose a novel model of ETCh in NOB to explain the role of reverse electron transport in the stimulation of oxygen consumption (previously attributed to hormesis).
氨氧化细菌 (AOB) 和亚硝酸盐氧化菌 (NOB) 的电子传递链 (ETCh) 参与将氨氧化为硝酸盐 (硝化作用)。一系列水溶性外源物质可能会干扰 ETCh 的运作。因此，硝化细菌的共生体可被用作生物传感器来检测水污染。该系统的一个惊人特征是在某些 ETCh 抑制剂存在的情况下，耗氧量增加。因此，为了阐明这种效应的机制（以及抑制剂之间的其他差异），我们分别监测硝化作用的第一阶段（AOB-硝化单胞菌）和第二阶段（NOB-硝化杆菌）细菌的呼吸作用。此外，我们还测量了质膜电位和 NAD(P)H 的还原水平。我们提出了一个新的 NOB 中的 ETCh 模型，以解释逆电子传递在刺激耗氧量中的作用（以前归因于应激反应）。
