| Fontibacter sp. SgZ-2厌氧腐殖质/Fe(Ⅲ)还原特性及电子传递机制研究 |
| 摘要点击 1579 全文点击 1101 投稿时间：2014-01-17 修订日期：2014-04-11 |
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| 中文关键词 Fontibacter 腐殖质 Fe(Ⅲ) 呼吸抑制剂 电子传递链 |
| 英文关键词 Fontibacter humus Fe(Ⅲ) respiratory inhibitor electron transport chain |
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| 中文摘要 |
| 腐殖质和Fe（Ⅲ）呼吸是重要的微生物胞外呼吸形式，电子传递途径是胞外呼吸研究的核心科学问题. 为全面理解1株铁还原新菌的电子转移特性和环境功能，以该菌株Fontibacter sp. SgZ-2为研究对象，考察其厌氧腐殖质和Fe（Ⅲ）还原特性，并探寻不同电子受体条件下的电子传递链组成差异. 采用厌氧恒温培养法研究了菌株厌氧还原特性. 结果表明，菌株SgZ-2具有还原腐殖质模式物[9，10-蒽醌-2，6-二磺酸（9，10-anthraquinone-2，6-disulfonic acid，AQDS）和9，10-蒽醌-2-磺酸（9，10-anthraquinone-2-sulfonic acid，AQS）]、腐殖酸（humic acids，HA）和可溶性Fe（Ⅲ）（Fe-EDTA和柠檬酸铁）以及铁氧化物[水铁矿（hydrous ferric oxide，HFO）]的能力. 发酵性糖类（葡萄糖和蔗糖）是菌株SgZ-2还原腐殖质和Fe（Ⅲ）的最佳电子供体. 另外，通过呼吸抑制剂法比较了菌株4种电子受体条件下（O2、AQS、Fe-EDTA和HFO）参与电子传递的电子载体差异. 结果表明，O2和Fe-EDTA还原条件下，菌株SgZ-2的电子传递链组分基本相似，均包括脱氢酶、醌泵和细胞色素b-c. AQS和HFO还原条件下，电子传递链组分只包含脱氢酶. 因而，菌株SgZ-2可溶性和不溶性Fe（Ⅲ）之间的电子传递链组分存在明显差异，并且可溶性受体之间（O2、Fe-EDTA和AQS）的电子传递链组成也不同. 本研究建立了1株铁还原新菌Fontibacter sp. SgZ-2不同电子受体条件下的电子传递链模型，并将电子传递机制的研究拓展到了Fontibacter菌属. 此研究将为理解该属的电子转移特性及其环境行为提供理论基础. |
| 英文摘要 |
| Humus and Fe(Ⅲ) respiration are important extracellular respiration metabolism. Electron transport pathway is the key issue of extracellular respiration. To understand the electron transport properties and the environmental behavior of a novel Fe(Ⅲ)-reducing bacterium, Fontibacter sp. SgZ-2, capacities of anaerobic humus/Fe(Ⅲ) reduction and electron transport mechanisms with four electron acceptors were investigated in this study. The results of anaerobic batch experiments indicated that strain SgZ-2 had the ability to reduce humus analog [9,10-anthraquinone-2,6-disulfonic acid (AQDS) and 9,10-anthraquinone-2-sulfonic acid (AQS)], humic acids (HA), soluble Fe(Ⅲ) (Fe-EDTA and Fe-citrate) and Fe(Ⅲ) oxides [hydrous ferric oxide (HFO)]. Fermentative sugars (glucose and sucrose) were the most effective electron donors in the humus/Fe(Ⅲ) reduction by strain SgZ-2. Additionally, differences of electron carrier participating in the process of electron transport with different electron acceptors (i. e., oxygen, AQS, Fe-EDTA and HFO) were investigated using respiratory inhibitors. The results suggested that similar respiratory chain components were involved in the reducing process of oxygen and Fe-EDTA, including dehydrogenase, quinones and cytochromes b-c. In comparison, only dehydrogenase was found to participate in the reduction of AQS and HFO. In conclusion, different electron transport pathways may be employed by strain SgZ-2 between insoluble and soluble electron acceptors or among soluble electron acceptors. Preliminary models of electron transport pathway with four electron acceptors were proposed for strain SgZ-2, and the study of electron transport mechanism was explored to the genus Fontibacter. All the results from this study are expected to help understand the electron transport properties and the environmental behavior of the genus Fontibacter. |
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