Novel Mechanism of Uranium Reduction Via Microbial Nanowires

通过微生物纳米线还原铀的新机制

基本信息

批准号：
7995994
负责人：
Gemma Reguera
金额：
$ 29.69万
依托单位：
MICHIGAN STATE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-02-01 至 2012-11-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7995994
关键词：
Agglutination Animal Model Bacteria Biological Biological Process Biological Sciences Biomass Bioremediations Biosensor Caliber Carbon Cell model Cells Collaborations Complex Data Defect Development Dimensions Discipline Electrodes Electron Transport Electronics Electrons Engineering Excision Foundations Genetic Geobacter Goals Gold Health In Situ In Vitro Knowledge Laboratories Leadership Length Lipid Bilayers Measures Mediating Membrane Lipids Metals Microbe Microbial Biofilms Minerals Modeling Molecular Monitor Nanotechnology Oxidants Oxides Physiological Physiology Pilum Precipitation Principal Investigator Process Proteins Public Health Radioactive Radioisotopes Research Research Personnel Research Support Roentgen Rays Role Screening procedure Site Spectrum Analysis Structure Superfund System Transmission Electron Microscopy Uranium Work X ray diffraction analysis X-Ray Diffraction absorption appendage base design electronic structure extracellular fundamental research ground water improved innovation insight microbial microorganism multidisciplinary mutant nanoscale nanostructured nanowire new technology novel novel strategies programs tool toxic metal

项目摘要

DESCRIPTION (provided by the applicant): One promising strategy for the in situ bioremediation of radioactive contaminants is to stimulate the activity of dissimilatory metal-reducing microorganisms to reductively precipitate uranium and other soluble toxic metals. While Geobacter bacteria are recognized as important agents for the reductive precipitation of soluble U(VI) to insoluble U(IV) in situ, the underlying mechanism is poorly understood. The reduction of U(VI) and other soluble contaminants by these microorganisms is directly dependent on the reduction of Fe(III) oxides, their natural electron acceptor. The recent discovery that Geobacter bacteria employ a novel mechanism for electron transport to Fe(III) oxides via protein nanowires (conductive pili) prompted us to investigate a potential role for these extracellular appendages in U(VI) reduction. Expression of pilus nanowires in the model organism Geobacter sulfurreducens led to a rapid precipitation of U(VI) to a U(IV) mineral along the nanowire length, demonstrating a previously unrecognized role for Geobacter nanowires in electron transfer to U(VI). Our objective in this proposal is to characterize the mechanism of U(VI) reduction mediated by Geobacter's pilus nanowires at the molecular and nano-scale level. As a complex biological and electronic structure of nanoscale dimensions (3-5 nm in diameter), insights into the structure and electronics of Geobacter's nanowires and their contribution to uranium reduction will require innovative approaches that integrate biological, physical and nanotechnological tools. To accomplish this, we bring together a team of researchers with recognized leadership in microbial metal reduction and nanowires, biosensor design, and environmental spectroscopy. Specifically, we propose the following aims: Specific Aim #1: Identify the molecular basis of nanowire-mediated electron transfer. Our working hypothesis, based on strong preliminary data presented in the application, is that the key nanowire components involved in U(VI) reduction can be identified by screening mutants with defects in nanowire functions and studying their effect in U(VI) transformations. Specific Aim #2: Develop nanostructured bioelectronic interfaces that integrate electroactive nanowires and lipid membranes with electrodes. Our working hypothesis, also based upon preliminary data, is that nanowire electrochemical processes can be mimicked and studied using nanostructured bioelectronic interfaces that integrate functional components of the nanowire system with electrodes. These studies are innovative in that they integrate microbiological, physical and nanotechnological tools to elucidate the novel mechanism of uranium reduction by microbial nanowires. At the completion of these studies we will have elucidated the basis of nanowire electron transfer to uranium at the molecular and nanoscale level, to enhance our knowledge of the key biological processes involved in the bioremediation of radionuclides and other soluble toxic metals and provide a basis for improved bioremediation processes.

描述（申请人提供）：放射性污染物的原位生物修复的一种有希望的策略是刺激异化金属还原微生物的活性，以还原沉淀铀和其他可溶性有毒金属。虽然地球细菌被认为是可溶性U（VI）还原为不溶性U（IV）的重要药物，但对基本机制的理解很少。这些微生物对U（VI）和其他可溶性污染物的还原直接取决于其自然电子受体的Fe（III）氧化物的还原。最近的发现，地球细菌采用了一种新型的通过蛋白纳米线（导电pili）向Fe（III）氧化物传输到Fe（III）的机制，这促使我们研究了这些细胞外附属物在U（VI）还原中的潜在作用。模型生物体地球杆菌中菌毛纳米线的表达导致U沿纳米线的u（vi）迅速沉淀到u（iv）矿物质，这表明在电子转移到u（VI）中，纳米杆菌在geobacter nanowires中的作用（VI）。我们在该提案中的目标是表征由分子和纳米级水平的Geobacter的Pilus纳米线介导的U（VI）还原的机制。作为纳米级维度的复杂生物学和电子结构（直径为3-5 nm），对地理杆菌纳米线的结构和电子的见解及其对铀还原的贡献将需要整合生物学，物理，物理和纳米技术工具的创新方法。为此，我们将一组研究人员组成，在微生物金属减少和纳米线，生物传感器设计和环境光谱方面具有公认的领导能力。具体而言，我们提出以下目的：特定目标＃1：确定纳米介介导的电子传递的分子基础。我们的工作假设基于应用程序中提出的强有初步数据，是可以通过筛选纳米线函数中具有缺陷的突变体并研究其在U（VI）转换中的作用来鉴定出参与U（VI）降低的关键纳米线组件。特定目的＃2：开发纳米结构的生物电子界面，将电活性纳米线和脂质膜与电极整合。我们的工作假设也基于初步数据，是可以使用纳米结构化的生物电子界面对纳米线电化学过程进行模仿和研究，从而将纳米线系统的功能成分与电极整合在一起。这些研究具有创新性，因为它们整合了微生物，物理和纳米技术工具，以阐明微生物纳米线减少铀的新机制。这些研究完成时，我们将阐明在分子和纳米级水平上向铀转移到铀的基础，以增强我们对辐射核酸盐和其他可溶性金属生物修复涉及的关键生物学过程的了解，并为改进的生物化过程提供基础。