NER: Molecular-To-Microscale Investigation Of Microbial Habitats: Exploratory Studies Using Molecular Probes and Microcomputed Tomography and Fluorescence

NER：微生物栖息地的分子到微观研究：使用分子探针、微计算机断层扫描和荧光的探索性研究

• 批准号: 0210819
• 负责人: Peggy O'Day
• 金额: $ 9.47万
• 依托单位: Arizona State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-07-15 至 2004-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0210819&HistoricalAwards=false
• 关键词: NER; Molecular; Microscale; Investigation; Microbial

O'DayNER- 0210819This proposal was received in response to the Nanoscale Science and Engineering initiative NSF 01-157, category NER, and is co-funded by the GEO and BIO Directorates. A significant challenge to integrating the study of microbiological and geochemical systems lies in visualizing, identifying, and measuring chemical reactions and feedbacks at appropriate length and time scales within their natural environments. This proposal seeks to explore a novel combination of molecular biological probes and synchrotron X-ray micro-computed tomography (m-CT) and fluorescence to obtain complementary information about physical and chemical microhabitats and microbial distribution in natural systems in two and three dimensions. Microbial communities are found in pore spaces and on mineral surfaces at length scales corresponding to individual bacteria and bacterial communities (~1-100 mm). Chemical reactions involving microorganisms and aqueous solutions, colloids, and minerals take place at the molecular level, but the interaction volumes of microbial communities may range from ~5-1000 mm3 or more. Conventional examination techniques such as electron or fluorescence microscopy require destructive sample preparation methods that can severely alter biological and physical structures. The aim of this exploratory study is to investigate a method for examining the distribution of microbial communities in situ and in three dimensions, and to develop complementary techniques for coupling element-specific spectroscopic probes and molecular biological probes. We propose to use nucleic acid biological probes directed against rRNA targets and tagged with heavy elements (iodine, gold, and silver) to map the spatial distribution of microbial communities within natural porous material using density-contrast synchrotron m-CT. In addition, we will investigate the ability of fluorescence m-CT measurements to map specific element distribution in two dimensions using these target elements and those of the mineral substrates. Based on density contrast and fluorescence mapping, we will explore the spatial distribution of microbial communities and mineral substrates, and attempt XANES spectroscopy of specific elements to gain chemical information. The coupling of physical and chemical data in two and three dimensions, with information content ranging from molecular to micron scale, will enable innovative future studies of fundamental processes involving element cycling among geologic fluids, minerals, and microbes.

该提案是根据纳米尺度科学与工程计划NSF 01-157 （NER类别）收到的，由GEO和BIO理事会共同资助。整合微生物和地球化学系统研究的一个重大挑战在于可视化、识别和测量在自然环境中适当长度和时间尺度的化学反应和反馈。本研究旨在探索分子生物学探针与同步加速器x射线微计算机断层扫描（m-CT）和荧光的新组合，以获得自然系统中物理和化学微栖息地以及微生物分布的二维和三维互补信息。微生物群落存在于孔隙空间和矿物表面，其长度尺度对应于单个细菌和细菌群落（~1-100 mm）。涉及微生物与水溶液、胶体和矿物质的化学反应发生在分子水平上，但微生物群落的相互作用体积可能在~5-1000 mm3或更多。传统的检查技术，如电子或荧光显微镜，需要破坏性的样品制备方法，可以严重改变生物和物理结构。本探索性研究的目的是探索一种原位和三维检测微生物群落分布的方法，并开发耦合元素特异性光谱探针和分子生物学探针的互补技术。我们建议使用针对rRNA靶点的核酸生物探针，并使用重元素（碘、金和银）标记，利用密度对比同步加速器m-CT绘制天然多孔材料中微生物群落的空间分布。此外，我们将研究荧光m-CT测量的能力，利用这些目标元素和矿物基质的元素在两个维度上绘制特定元素分布。基于密度对比和荧光制图，我们将探索微生物群落和矿物基质的空间分布，并尝试对特定元素进行XANES光谱分析以获得化学信息。二维和三维物理和化学数据的耦合，其信息内容范围从分子尺度到微米尺度，将使未来对涉及地质流体、矿物和微生物之间元素循环的基本过程的创新研究成为可能。