Understanding microbial manganese-oxidizing communities and physiological mechanisms in metal oxide-rich hydrothermal sediments using a metagenomic and metatranscriptomic approach

使用宏基因组和宏转录组方法了解富含金属氧化物热液沉积物中的微生物锰氧化群落和生理机制

• 批准号: 1129553
• 负责人: Bradley Tebo
• 金额: $ 79.93万
• 依托单位: Oregon Health & Science University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-15 至 2015-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1129553&HistoricalAwards=false
• 关键词: Understanding; microbial; manganese; oxidizing; communities

Hydrothermal systems are important sources of dissolved Mn to the oceans. Upon oxidation of Mn(II), Mn(III,IV) oxides are deposited at the sea floor as crusts, nodules and sediments both near and far from the sources. Microbial activity has long been recognized as being important to the fate of Mn in these hydrothermal systems, yet we know very little about the organisms that catalyze Mn oxidation, the mechanisms by which Mn is oxidized or the physiological function that Mn oxidation serves. The overarching goals of this project are to reveal the organisms and mechanism(s) underlying Mn(II) oxidation, to evaluate whether hydrothermal Mn oxidizers may obtain energy from Mn oxidation, and test whether thermophilic Mn oxidizers exist. Specifically, the project will: 1) evaluate whether we can identify certain genomic sequences that correlate to the presence/concentration of Mn oxides (and hence Mn(II)- oxidizing bacteria) by comparing the metagenomes of ferromanganese (containing both Mn and Fe oxides) microbial mats with ferruginous (Fe oxide only) mats from Lau Basin and Loihi Seamount; 2) use peptide probes bound to magnetic particles for selectively binding and capturing Mn oxide particles and characterizing the particles using phylogenetic and functional gene (PCR and FISH) and transcriptomic analysis; 3) assess the main pathways of carbon fixation in ferromanganese microbial mats as compared to ferruginous mats as a possible indicator of Mn-based auto/mixotrophy using genomic approaches and substrate stimulated (e.g., addition of Mn(II)) CO2 fixation measurements and stable isotope probing (SIP) genomic analysis; and 4) isolate and characterize Mn(II)-oxidizing bacteria and determine whether thermophilic Mn oxidizers exist.Intellectual meritThe results of this research will increase our understanding of Mn(II) oxidation in hydrothermal sediments, identify microorganisms that are the environmentally relevant Mn oxidizers and begin to address the long standing question of whether Mn auto/mixotrophy exists using approaches not based on the biases associated with cultivation. Ultimately this information is critical to our understanding of biogeochemical cycles (Mn oxidation and Mn oxides impact many other elemental cycles, including carbon, sulfur, and heavy metals) and the natural attenuation of toxic metal and organic compounds; this may lead to improved technologies for environmental remediation. Because Mn oxides are believed to be an analog to the ancestral Mn centers in photosystem II, this research may also lend new insights into ancient biogeochemistry occurring before the Great Oxidation Event.Broader impactsThe project will provide support and training for one Ph.D. student and one postdoctoral researcher, and will contribute to the education of undergraduate and highly qualified high school students through independent research projects and mentorships. They will participate in a geoscience education program targeting the education of 6-12 grade Alaskan Native Americans. In addition, this project will contribute to a training program targeted to middle school teachers that highlights the connections between chemistry, biology, and geology in the environment. The results of the work will be broadly disseminated through presentations, publications, and the World Wide Web.

热液系统是海洋中溶解的锰的重要来源。当锰(II)氧化时，锰(III，IV)氧化物以结壳、结核和沉积物的形式沉积在海底，无论是在源头附近还是远离源头。长期以来，微生物的活动一直被认为对这些热液系统中的锰的去向具有重要的影响，但我们对催化锰氧化的生物、锰氧化的机理或锰氧化的生理功能知之甚少。该项目的总体目标是揭示锰(II)氧化的生物和机理(S)，评估热液锰氧化剂是否可以从锰氧化中获得能量，并测试是否存在嗜热锰氧化剂。具体地说，该计划将：1)评估我们能否通过比较来自刘盆地和洛伊希海山的锰铁(同时包含锰和铁氧化物)微生物垫的元基因组和铁质(仅含铁氧化物)微生物垫的基因组，来评估我们是否能够识别与氧化锰(因此也包括锰(II)氧化细菌)的存在/浓度相关的某些基因组序列；2)使用结合在磁性颗粒上的多肽探针选择性地结合和捕获氧化锰颗粒，并使用系统发育和功能基因(聚合酶链式反应和FISH)和转录组学分析来表征颗粒；3)利用基因组方法和底物刺激(例如，添加锰(II))二氧化碳固定测量和稳定同位素探测(SIP)基因组分析，评估铁锰微生物垫与铁质垫相比的主要固碳途径，作为基于锰的自养/混合营养的可能指标；4)分离和鉴定锰(II)氧化菌，确定是否存在嗜热锰氧化菌。智力价值这项研究的结果将增加我们对热液沉积物中锰(II)氧化的理解，识别与环境相关的锰氧化菌，并开始解决长期存在的问题，即是否存在锰的自养/混合营养，而不是基于与培养相关的偏见。归根结底，这些信息对我们理解生物地球化学循环(锰氧化和锰氧化物影响许多其他元素循环，包括碳、硫和重金属)以及有毒金属和有机化合物的自然衰减至关重要；这可能会导致环境修复技术的改进。由于锰氧化物被认为是光系统II中祖先锰中心的类似物，这项研究也可能为了解发生在大氧化事件之前的古代生物地球化学提供新的见解。广泛的影响该项目将为一名博士生和一名博士后研究员提供支持和培训，并将通过独立的研究项目和导师为本科生和高素质高中生的教育做出贡献。他们将参加一项针对6-12年级阿拉斯加原住民教育的地球科学教育计划。此外，该项目还将促进一项针对中学教师的培训计划，该计划突出了化学、生物学和环境地质学之间的联系。这项工作的成果将通过演讲、出版物和万维网广泛传播。