Chemical Mapping of Chromate Uptake, Localization, and Reduction in Remediating B

修复 B 中铬酸盐吸收、定位和还原的化学图谱

• 批准号: 7572265
• 负责人: Joseph MK Irudayaraj
• 金额: $ 28.63万
• 依托单位: PURDUE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-01-08 至 2011-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7572265
• 关键词: Address; Bacteria; Bioavailable; Biochemical; Biochemistry; Biological; Biological Models; Biology; Bioreactors; Bioremediations; Catalysis; Cell Culture Techniques; Cell Survival; Cell membrane; Cell surface; Cells; Chemicals; Chromates; Chromium; Complex; Cytoplasm; Cytosol; Development; Distal; Drug Metabolic Detoxication; Engineering; Enhancers; Environment; Environmental Impact; Environmental Pollution; Environmental Risk Factor; Enzymes; Event; Fluorescence; Generations; Gold; Growth; Hazardous Waste Sites; Health; Heavy Metals; Human; ICP-AES; Image; Imaging Techniques; Immobilization; In Situ; In Vitro; Investigation; Ions; Knowledge; Laboratories; Life; Link; Maps; Measurement; Measures; Mediating; Metabolic; Metals; Methodology; Microbe; Microscopy; Molecular; Monitor; Nanostructures; Nutrient; Organism; Outcome; Oxidoreductase; Performance; Polyethylene Glycols; Population; Powder Diffraction; Process; Proteobacteria; Resolution; Roentgen Rays; Scheme; Shapes; Shewanella; Signal Transduction; Silver; Site; Soil; Source; Structure; Sulfhydryl Compounds; Surface; Testing; Toxic effect; United States; Variant; Work; appendage; base; carcinogenicity; chromium hexavalent ion; cost; improved; in vivo; microbial; microorganism; nanoparticle; nanoprobe; nanorod; nanoscale; novel; particle; periplasm; pollutant; remediation; respiratory; response; success; uptake

DESCRIPTION (provided by applicant): Cr(VI) contamination of soil and groundwater is a significant problem worldwide. In the United States, chromate is the third most common contaminant of hazardous waste sites and the second most common inorganic contaminant found in the environment. In situ and ex situ bioremediation processes that exploit the intrinsic metabolic capabilities of dissimilatory metal ion-reducing bacteria (DMRB) remain potent, potentially cost-effective approaches to the reductive immobilization or detoxification of environmental contaminants. The microbial catalysis of Cr(VI) reduction to sparingly soluble, less bioavailable Cr(III), for example, is a promising remediation strategy for Cr(VI)-contaminated subsurface soil and groundwater environments. The genus Shewanella represents one of the few groups of microorganisms that have received intensive investigation because of their wide ecological distribution, diverse respiratory capacities, and environmental relevance. Despite several advances made in elucidating Shewanella biology as it relates to chromate transformation, fundamental questions about the specific chromate reduction mechanism remain unclear. This information gap includes (i) the identity of dedicated chromate reductase(s), (ii) the cellular localization of chromate transformation (e.g., distal appendages, outer cell surface, periplasm, cytoplasmic membrane, cytosol), and (iii) the environmental parameters under which microbial populations have the greatest specific chromate reduction rates. The problem in predicting and assessing bioremediation performance is compounded by the lack of fundamental knowledge of the molecular basis, regulatory mechanisms, and biochemistry enabling bacterial metal-reducing capabilities. We propose to engineer nanoscale methodologies, comprising of chromate-tagged nanoparticles and intracellularly grown gold nanoislands to function as enhancers for Surface Enhanced resonance Raman scattering probing to generate chemical maps of chromate reduction sites as well as to monitor the reduction dynamics in exquisite molecular and single-organism detail. Objectives of this study are to 1) assess the impact of gold nanoparticle composition, geometry, and functionality on cell viability, growth, and efficacy of microbial chromate reduction using S. oneidensis as a model system; 2) track the localization of chromate transformation at single-cell resolution using functionalized gold nanostructures as well as using intracellularly grown gold nanoislands by Raman chemical imaging; and 3) evaluate the influence of bioremediation-relevant environmental factors on chromate transport, localization, and reduction rates. The development of passive and active nanoprobes in conjunction with confocal Raman chemical imaging will constitute a significant step in enabling a platform for dynamic monitoring of intracellular events and compartmentalization of metal reduction sites at single-cell resolution. The knowledge gained from this novel study will contribute to the development of scientifically grounded strategies for improving bioremediation efficacy.

描述（由申请人提供）： 土壤和地下水的六价铬污染是世界范围内的一个重大问题。在美国，铬酸盐是危险废物场的第三大常见污染物，也是环境中第二大常见的无机污染物。利用异化金属离子还原菌（DMRB）内在代谢能力的原位和异位生物修复过程仍然是环境污染物还原固定或解毒的有效且具有潜在成本效益的方法。例如，微生物催化 Cr(VI) 还原为难溶、生物利用度较低的 Cr(III)，是一种很有前景的修复 Cr(VI) 污染的地下土壤和地下水环境的策略。希瓦氏菌属因其广泛的生态分布、多样化的呼吸能力和环境相关性而成为少数受到深入研究的微生物群之一。尽管在阐明希瓦氏菌与铬酸盐转化相关的生物学方面取得了一些进展，但有关特定铬酸盐还原机制的基本问题仍不清楚。该信息差距包括（i）专用铬酸盐还原酶的身份，（ii）铬酸盐转化的细胞定位（例如远端附属物，外细胞表面，周质，细胞质膜，细胞质），以及（iii）环境微生物种群具有最大特定铬酸盐还原率的参数。由于缺乏对细菌金属还原能力的分子基础、调节机制和生物化学的基础知识，预测和评估生物修复性能的问题变得更加复杂。我们建议设计纳米级方法，包括铬酸盐标记的纳米颗粒和细胞内生长的金纳米岛，作为表面增强共振拉曼散射探测的增强剂，以生成铬酸盐还原位点的化学图，并监测精致分子和单金属中的还原动态。 - 有机体细节。本研究的目的是 1) 使用 S. oneidensis 作为模型系统，评估金纳米粒子的组成、几何形状和功能对细胞活力、生长和微生物铬酸盐还原功效的影响； 2) 使用功能化金纳米结构以及通过拉曼化学成像使用细胞内生长的金纳米岛以单细胞分辨率追踪铬酸盐转化的定位； 3) 评估生物修复相关环境因素对铬酸盐迁移、定位和还原率的影响。被动和主动纳米探针的开发与共焦拉曼化学成像相结合，将构成一个重要的一步，以实现动态监测细胞内事件和以单细胞分辨率划分金属还原位点的平台。从这项新颖的研究中获得的知识将有助于制定有科学依据的策略，以提高生物修复功效。