Project 5: Molecular Insight into Dioxin Degradation by Microbes and Microbial

项目 5：微生物和微生物降解二恶英的分子洞察

• 批准号: 8695355
• 负责人: GERBEN J ZYLSTRA
• 金额: $ 45.44万
• 依托单位: MICHIGAN STATE UNIVERSITY
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/8695355
• 关键词: Bacteria; Biochemical; Biochemistry; Biodegradation; Biological Availability; Cells; Communities; DNA; Dioxins; Dioxygenases; Drug Metabolic Detoxication; Engineering; Environment; Enzymes; Essential Genes; Event; Evolution; Exposure to; Fire - disasters; Food; Genes; Genetic; Goals; Instruction; Knowledge; Libraries; Ligands; Measurement; Metabolic; Metabolic Pathway; Metagenomics; Microbe; Modeling; Molecular; Movement; Nature; Operon; Organism; Pathway interactions; Physiology; Play; Population; Process; RNA; Risk Factors; Role; Sampling; Site; Source; System; Toxic effect; Work; anthropogenesis; dioxin dioxygenase; exposed human population; forest; genome-wide; improved; insight; microbial; microbial community; microorganism; mineralization; molecular marker; new technology; novel; oxidation; pollutant; pressure; remediation; repository; response; stable isotope; transcriptomics

PROJECT SUMMARY (See instructions): The microbial world is hugely diverse owing to its 3.7 billion years of evolution, which provides for both the opportunity of undiscovered metabolic capacity, including that for pollutant degradation, and the challenge of detecting, recovering, and characterizing this activity. While microbes have been exposed to small amounts of dioxins over millennia due to natural events such as forest fires, it is only in the last century or so that dioxins have become an abundant food source in nature due to anthropogenic activity. This may explain why there are only a few well characterized microbial strains with the ability to mineralize dioxins. We propose to characterize the microbial response to dioxins in pure cultures and microbial communities to understand the limitations on environmental detoxification of this hazardous class of compounds. Our long term goal is to develop microbes for enhanced biodegradation, to identify molecular markers to aid in site assessment, and to develop models for prediction of biodegradation at contaminated sites. Our Specific Aims in the present proposal are: (1) to elucidate the physiology, biochemistry, and genetics of chlorinated dioxins degradation in order to understand and improve the remediation of these highly toxic pollutants, (2) to assess (meta)genome-wide responses and metabolic capabilities by conducting physiogenomic studies of microorganisms and active microbial communities in response to chlorinated dioxins including those from environmentally important geosorbents, and (3) to explore and recover nature's catalytic diversity with the goal of developing a comprehensive profile of microbial community metabolic capabilities for degradation and/or mineralization of chlorinated dioxins and dioxin-like compounds in the environment. We propose to use enrichments to help identify the functionally active populations and hence genes, to use stable isotope probing to recover DNA from the active degrading populations, to use metagenomic and metatranscriptomic libraries and the novel technology of massive parallel RNA bait capture of target DNA and RNA to recover the full genes and operons, to use this information to understand the biochemistry of dioxins degradation, and to use transcriptomic and biochemical analyses of a model dioxin degrading bacterium to understand the total response of the organism to the various pressures involved during the degradation process (i.e. substrate and metabolite toxicity, metabolic fluxes, etc.).

项目总结（见说明）： 由于其37亿年的进化，微生物世界是非常多样化的，这既提供了未被发现的代谢能力的机会，包括污染物降解，也提供了检测，恢复和表征这种活动的挑战。虽然几千年来，由于森林火灾等自然事件，微生物一直接触到少量的二恶英，但由于人类活动，二恶英只是在上个世纪左右才成为自然界中丰富的食物来源。这可以解释为什么只有少数特征良好的微生物菌株具有矿化二恶英的能力。我们建议在纯培养物和微生物群落中表征微生物对二恶英的反应，以了解这类危险化合物对环境解毒的限制。我们的长期目标是开发用于增强生物降解的微生物，识别分子标记以帮助现场评估，并开发用于预测污染场地生物降解的模型。我们在本提案中的具体目标是：（1）阐明氯代二恶英降解的生理学、生物化学和遗传学，以了解和改进这些剧毒污染物的修复，（2）评估（Meta）基因组-通过对微生物和活性微生物群落进行生理基因组学研究，以应对氯化二恶英，包括来自环境中的氯化二恶英，（3）探索和恢复自然界的催化多样性，目的是全面了解微生物群落降解和/或矿化环境中氯化二恶英和二恶英类化合物的代谢能力。我们建议使用富集来帮助识别功能活性群体和基因，使用稳定同位素探测来从活性降解群体中回收DNA，使用宏基因组和元转录组文库以及大规模平行RNA诱饵捕获靶DNA和RNA的新技术来回收完整的基因和操纵子，使用这些信息来了解二恶英降解的生物化学，并利用对二恶英降解模式细菌的转录组学和生物化学分析，了解生物体对降解过程中所涉及的各种压力的总体反应（即底物和代谢物毒性、代谢通量等）。