Greatlion的个人博客分享 http://blog.sciencenet.cn/u/Greatlion

博文

细菌可用其菌毛清除铀污染

已有 2704 次阅读 2011-9-8 20:28 |系统分类:论文交流

原文摘要:Extracellular reduction of uranium via Geobacter conductive pili as a protective cellular mechanism The in situ stimulation of Fe(III) oxide reduction by Geobacter bacteria leads to the concomitant precipitation of hexavalent uranium [U(VI)] from groundwater. Despite its promise for the bioremediation of uranium contaminants, the biological mechanism behind this reaction remains elusive. Because Fe(III) oxide reduction requires the expression of Geobacter's conductive pili, we evaluated their contribution to uranium reduction in Geobacter sulfurreducens grown under pili-inducing or noninducing conditions. A pilin-deficient mutant and a genetically complemented strain with reduced outer membrane c-cytochrome content were used as controls. Pili expression significantly enhanced the rate and extent of uranium immobilization per cell and prevented periplasmic mineralization. As a result, pili expression also preserved the vital respiratory activities of the cell envelope and the cell's viability. Uranium preferentially precipitated along the pili and, to a lesser extent, on outer membrane redox-active foci. In contrast, the pilus-defective strains had different degrees of periplasmic mineralization matching well with their outer membrane c-cytochrome content. X-ray absorption spectroscopy analyses demonstrated the extracellular reduction of U(VI) by the pili to mononuclear tetravalent uranium U(IV) complexed by carbon-containing ligands, consistent with a biological reduction. In contrast, the U(IV) in the pilin-deficient mutant cells also required an additional phosphorous ligand, in agreement with the predominantly periplasmic mineralization of uranium observed in this strain. These findings demonstrate a previously unrecognized role for Geobacter conductive pili in the extracellular reduction of uranium, and highlight its essential function as a catalytic and protective cellular mechanism that is of interest for the bioremediation of uranium-contaminated groundwater.
作 者:Cologgi, Dena L.; Lampa-Pastirk, Sanela; Speers, Allison M.; Kelly, Shelly D.; Reguera, Gemma
期刊名称: Proceedings of the National Academy of Sciences
发表日期: September 6, 2011
原文链接:http://www.pnas.org/content/early/2011/08/30/1108616108.abstract?sid=bfb9ee8e-4f70-49a7-8cb8-f08289fffed8
DOI: 10.1073/pnas.1108616108
ISBN: 0027-8424

http://blog.sciencenet.cn/blog-41454-484240.html

上一篇:污染物处理微生物群落的元基因组学分析
下一篇:[转载]读懂系统发育树

0

该博文允许注册用户评论 请点击登录 评论 (0 个评论)

数据加载中...
扫一扫,分享此博文

Archiver|手机版|科学网 ( 京ICP备14006957 )

GMT+8, 2019-9-15 20:41

Powered by ScienceNet.cn

Copyright © 2007- 中国科学报社

返回顶部