Bioavailibility of Toxicants as Reflected in the In Situ Microbial Community Ecology and Relationship to Defensible End-Points

原位微生物群落生态中反映的有毒物质的生物利用度及其与防御终点的关系

• 批准号: 9814813
• 负责人: David White
• 金额: $ 48.59万
• 依托单位: University of Tennessee Knoxville
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-10-01 至 2002-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9814813&HistoricalAwards=false
• 关键词: Bioavailibility; Toxicants; Reflected; Situ; Microbial

9814813White Contamination of soil and water by polluting organic compounds or metals has been shown to alter the composition of native communities of microbes in the environment. Recovery by the microbial community from contaminant effects and possible remediation of the environment are dependent upon a host of factors, biotic and abiotic, operating over varying time frames and spatial scales. A critical determinant of the recovery and remediation process is the composition of the initial, affected microbial community, in terms of taxonomic representation, abundance of individual populations, and metabolic status. The ability to assess, characterize, and track all the microbial species comprising a local community has been greatly enhanced by modern molecular methods of analysis for two major classes of bacterial compounds: bacterial cell wall lipids, and the DNA sequence of various ribosomal genes (usually the 16S rRNA gene). Obviating the need to grow or culture the bacteria in the laboratory, these molecular methods can provide rapid, accurate identification of microbial populations within soil or water samples, and preliminary indications of their relative abundances and metabolic states. As a pioneer in the development of the "signature lipid biomarker" methodology, Dr. White and his colleagues are now expanding the technology to include DNA sequence analyses, and to apply these methods to the study of contrasting contaminated and uncontaminated sites at two major field locations, at Wurtsmith AFB in Michigan and at Cocodrie marsh in Louisiana, both subject to persistent hydrocarbon contaminations. One overall goal is to test the hypothesis that microbial community composition will change in a directional and predictable manner as contaminants are attenuated either in space (over a gradient of contaminant concentration) or through time (over several seasons of microbial growth and metabolism). An auxiliary hypothesis under test is whether there are "sentinel" species of microbes that signal particular states of remediation. The development of effective bioremediation strategies for contaminated soils or waters has been moving away from the "silver bullet" approach that relies upon a single agent (adding one particular bacterial species) to a more ecological approach that emphasizes metabolic dynamics among microbial community members in the environment. Rapid, accurate identification of the full range of microbes present in local communities increasingly is possible with the use of modern molecular methods of cell wall lipid analysis and DNA sequencing of diagnostic gene regions. In turn, the characterization of microbial community composition may reveal distinctive assemblages of "sentinel" species that correlate with various states of environmental remediation.

9814813White 污染有机化合物或金属造成的土壤和水污染已被证明会改变环境中原生微生物群落的组成。微生物群落从污染物影响中恢复以及可能的环境修复取决于许多生物和非生物因素，这些因素在不同的时间范围和空间尺度上发挥作用。恢复和修复过程的一个关键决定因素是最初受影响的微生物群落的组成，包括分类学代表性、个体种群的丰度和代谢状态。通过现代分子分析方法，对两大类细菌化合物进行评估、表征和追踪构成当地群落的所有微生物物种的能力得到极大增强：细菌细胞壁脂质和各种核糖体基因（通常是 16S rRNA 基因）的 DNA 序列。这些分子方法无需在实验室中培养或培养细菌，可以快速、准确地识别土壤或水样中的微生物种群，并初步指示其相对丰度和代谢状态。作为开发“标志性脂质生物标志物”方法的先驱，怀特博士和他的同事们现在正在扩展该技术，将 DNA 序列分析纳入其中，并将这些方法应用于对比两个主要现场地点（密歇根州的沃特史密斯空军基地和路易斯安那州的科科德里沼泽）的受污染和未受污染地点的研究，这两个地点都受到持久性碳氢化合物的影响。 污染。一个总体目标是检验这样一种假设：随着污染物在空间（污染物浓度梯度）或时间（微生物生长和代谢的几个季节）的衰减，微生物群落组成将以定向和可预测的方式发生变化。正在测试的一个辅助假设是是否存在发出特定修复状态信号的“哨兵”微生物物种。针对受污染土壤或水域的有效生物修复策略的开发已经从依赖单一药剂（添加一种特定细菌物种）的“银弹”方法转向强调环境中微生物群落成员之间的代谢动态的更加生态的方法。通过使用细胞壁脂质分析和诊断基因区域 DNA 测序的现代分子方法，快速、准确地识别当地社区中存在的各种微生物越来越成为可能。反过来，微生物群落组成的表征可能揭示与环境修复的各种状态相关的“哨兵”物种的独特组合。