In Vivo Characterization of Bacteria-mediated Extracellular Reduction of Chromium

细菌介导的细胞外铬还原的体内表征

• 批准号: 7995995
• 负责人: H Peter Lu
• 金额: $ 35.31万
• 依托单位: BOWLING GREEN STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-01-13 至 2012-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7995995
• 关键词: Bacteria; Bioremediations; Cell surface; Chromium; Complex; Cytochrome c Group; Cytochromes; Electron Microscopy; Goals; Gold; Health; Human; Image; In Situ; In Vitro; Individual; Iron; Kinetics; Location; Measurement; Measures; Mediating; Metals; Methods; Microscopy; Molecular; Oxides; Oxidoreductase; Play; Resolution; Role; Scanning; Scanning Electron Microscopy; Science; Shewanella; Solutions; Surface; Testing; Toxic effect; Water; base; chromium hexavalent ion; extracellular; hematite; in vivo; nanometer; nanoscale; nanosized; oxidation; particle; research study; superfund site

DESCRIPTION (provided by the applicant): Hexavalent chromium[Cr(VI)]exists at the Superfund sites where it poses major health concerns to humans. Bacteria-mediated in situ transformation of water soluble and toxic Cr(VI) to less soluble/toxic Cr(III) represents a promising method to contain and treat Cr(VI). However, the molecular mechanisms by which bacteria reduce Cr(VI) remain undetermined. Reduction of Cr(VI) by dissimilatory iron (Fe) reducing bacterium Shewanella oneidensis results in formation of nano-sized Cr(III) particles on the cell surfaces. We hypothesize that cell surface-exposed cytochromes MtrC and OmcA of S. oneidensis are involved in the formation of Cr(III) by reducing Cr(VI) directly as Cr(VI) terminal reductases and indirectly as Fe(III) oxide terminal reductases to produce Fe(II) that in turn reduces Cr(VI). We plan to use nanoscale AFM correlated SERS imaging microscopy (AFM-CSIM) developed by us along with other methods to test our hypothesis. AFM-CSIM can simultaneously determine the locations of cytochromes and nano-sized metal particles as well as their oxidation states on the bacterial surfaces at nanometer-resolution. Co-localization of MtrC and OmcA with nano-sized Cr(III) and Fe(III) particles by AFM-CSIM will provide direct evidences to support our hypothesis. Other approaches (e.g. immuno-gold localization with scanning electron microscopy and the measurements of Cr(VI) reductase activity of purified MtrC and OmcA) will be used to validate the AFM-CSIM results. Successful completion of this project will help not only achieve our long-term goal of understanding the molecular mechanisms by which bacteria reduce Cr(VI), but also develop science-based solutions to mitigate the toxic effects of Cr(VI) at the Superfund sites.

描述（申请人提供）： 六价铬[CR（VI）]存在于超级基金站点，对人类构成了重大健康关注。细菌介导的水溶性和有毒CR（VI）到较少溶解/有毒CR（III）的原位转化是一种有希望的含有和处理Cr（VI）的方法。但是，细菌减少Cr（VI）的分子机制仍未确定。通过异化铁（Fe）减少CR（VI）减少CR（Fe），减少Shewanella Oneidensis的细菌会导致在细胞表面上形成纳米大小的Cr（III）颗粒。我们假设Oneidensis的细胞表面暴露的细胞色素MTRC和OMCA通过直接减少Cr（vi）作为Cr（VI）末端还原酶，并间接为Fe（III）氧化物末端还原酶，以产生Fe（II）。我们计划使用我们开发的纳米级AFM相关SERS成像显微镜（AFM-CSIM）以及其他方法来检验我们的假设。 AFM-CSIM可以同时确定细胞色素和纳米大小的金属颗粒的位置及其在纳米分辨率下细菌表面上的氧化态。 AFM-CSIM与纳米尺寸CR（III）和Fe（III）颗粒的MTRC和OMCA共定位将提供直接证据以支持我们的假设。其他方法（例如，通过扫描电子显微镜进行免疫金定位以及纯化的MTRC和OMCA的Cr（VI）还原酶活性的测量）将用于验证AFM-CSIM结果。该项目的成功完成将不仅有助于我们实现我们的长期目标，以了解细菌减少CR（VI）的分子机制，而且还可以开发基于科学的解决方案来减轻Superfund网站上CR（VI）的毒性作用。

项目成果

Single-cell imaging and spectroscopic analyses of Cr(VI) reduction on the surface of bacterial cells.

• DOI: 10.1021/la303779y
• 发表时间: 2013-01-22
• 期刊: Langmuir : the ACS journal of surfaces and colloids
• 作者: Wang Y;Sevinc PC;Belchik SM;Fredrickson J;Shi L;Lu HP
• 通讯作者: Lu HP

Biofilm shows spatially stratified metabolic responses to contaminant exposure.

• DOI: 10.1111/j.1462-2920.2012.02850.x
• 发表时间: 2012-11
• 期刊: Environmental microbiology
• 影响因子: 5.1
• 作者: Cao B;Majors PD;Ahmed B;Renslow RS;Silvia CP;Shi L;Kjelleberg S;Fredrickson JK;Beyenal H
• 通讯作者: Beyenal H