Effects of Incubation Conditions on Cr(VI) Reduction by c-type Cytochromes in Intact Shewanella oneidensis MR-1 Cells

文献类型： 外文期刊

第一作者： Han, Rui

作者： Han, Rui;Han, Rui;Li, Fangbai;Liu, Tongxu;Li, Xiaomin;Wu, Yundang;Wang, Ying;Chen, Dandan

作者机构：

关键词： c-type cytochromes;Shewanella oneidensis MR-1;Cr(VI) reduction;intact cells;incubation conditions

期刊名称：FRONTIERS IN MICROBIOLOGY （ 影响因子：5.64； 五年影响因子：6.32 ）

ISSN： 1664-302X

年卷期： 2016 年 7 卷

页码：

收录情况： SCI

摘要： It is widely recognized that the outer membrane c-type cytochromes (OM c-Cyts) of metal-reducing bacteria play a key role in microbial metal reduction processes. However, the in situ redox status of OM c-Cyts during microbial metal reduction processes remain poorly understood. In this study, diffuse-transmission UV/Vis spectroscopy is used to investigate the in situ spectral reaction of Cr(VI) reduction by c-Cyts in intact Shewanella oneidensis MR-1 cells under different incubation conditions. The reduced c-Cyts decreased transiently at the beginning and then recovered gradually over time. The Cr(VI) reduction rates decreased with increasing initial Cr(VI) concentrations, and Cr(III) was identified as a reduced product. The presence of Cr(III) substantially inhibited Cr(VI) reduction and the recovery of reduced c-Cyts, indicating that Cr(III) might inhibit cell growth. Cr(VI) reduction rates increased with increasing cell density. The highest Cr(VI) reduction rate and fastest recovery of c-Cyts were obtained at pH 7.0 and 30 degrees C, with sodium lactate serving as an electron donor. The presence of 02 strongly inhibited Cr(VI) reduction, suggesting that 02 might compete with Cr(VI) as an electron acceptor in cells. This study provides a case of directly examining in vivo reaction properties of an outer-membrane enzyme during microbial metal reduction processes under non-invasive physiological conditions.

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[2]In situ spectral kinetics of quinone reduction by c-type cytochromes in intact Shewanella oneidensis MR-1 cells. Han, Rui,Li, Xiaomin,Wu, Yundang,Li, Fangbai,Liu, Tongxu,Han, Rui. 2017

[3]Axial Ligation of Heme in c-Type Cytochromes of Living Shewanella oneidensis: A New Insight into Enhanced Extracellular Electron Transfer. Yuan, Yong,Zhou, Shungui,Li, Laicai. 2015

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