OCE-PRF Uncovering the Genetic Basis of Novel Oxidative Extracellular Electron Transfer Mechanisms in an Electrochemically Active Marine Bacterial Consortium

OCE-PRF 揭示电化学活性海洋细菌群落中新型氧化细胞外电子转移机制的遗传基础

• 批准号: 2126677
• 负责人: Joshua Sackett
• 金额: $ 29.84万
• 依托单位: University of Cincinnati Main Campus
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-07-01 至 2024-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2126677&HistoricalAwards=false
• 关键词: OCE; PRF; Uncovering; Genetic; Basis

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).Recently, it was discovered that some microbes are capable of respiring (‘breathing’) or deriving energy (‘eating’) from solid-phase minerals located outside the cell. This is facilitated by extracellular electron transfer (EET): the process by which some microbes shuttle electrons into and out of their cells from/to solid materials. EET can be evaluated in a laboratory setting, in which microbes are grown on electrodes and the generation of biological current – the flow of electrons to/from the electrode – can be measured. In these experiments, the electrodes are poised at specific voltages (redox potentials) that function as proxies for mineral surfaces. Much of our knowledge of EET has been obtained from just a few model organisms capable of respiratory mineral reduction, in which electrons are transferred out of the cell onto oxidized solid-phase materials, such as iron and manganese oxides, which are prevalent in freshwater and marine sediments. However, little is known about the mechanism or ecological implications of oxidative EET, the process by which electrons are transferred from reduced minerals into the cell as a source of energy (‘eating’). Evidence from microbial community surveys suggests that organisms inhabiting a wide variety of habitats, including both freshwater and marine environments, may be capable of EET. This project will expand upon our understanding of the genetic basis of oxidative EET in microbes isolated from marine sediments grown individually and in a co-culture consortium. Further, this information will provide insight into the role of EET in global elemental cycling and may inform alternative clean energy generation, bioremediation, and wastewater treatment efforts using electrochemically active organisms. This project will provide educational and training opportunities to undergraduate students, who will be recruited to aid with research tasks. Community outreach activities, particularly in underserved areas of Cincinnati, will be organized to provide middle-school aged children with hands-on educational opportunities focused around electromicrobiology and bioenergy production.The discovery of extracellular electron transfer (EET) has important implications for a wide range of biogeochemically important processes. In marine subsurface sediments, where microbial biomass is estimated to account for 0.6% of the total biomass on Earth, lithotrophic metabolisms are difficult to detect since the genetic basis of oxidative EET remains largely unknown and uncharacterized, and ‘omics’ studies fail to identify genes or proteins involved in this process. This significant knowledge gap, coupled with direct measurements of microbial metabolism in the ‘deep’ and ‘dark’ ocean far exceeding the expected models based on the influx of organic carbon to the system, strongly suggest that the importance of lithotrophic metabolisms, and the mechanisms by which these metabolisms operate, has been overlooked and understanding and detection of these processes in nature is crucial. Furthermore, the ecology of EET in polymicrobial communities is poorly understood, but a variety of data imply that diverse microbial communities are important for stable and processive environmental function. Thus, the overarching goal of this project is to gain insight into the genetic basis of EET in oxidative processes, and into the ecological implications of these processes, in two genetically tractable, electrode-oxidizing lithotrophic marine sediment bacteria in pure culture and in co-culture. Cutting-edge, targeted high-throughput sequencing techniques will be used to identify genes putatively involved in oxidative EET and genes that facilitate interspecies electron transfer in co-cultures. Gene deletion mutants will be constructed, and mutant strains will be assayed for their capacity for oxidative EET and interspecies electron transfer. Not only will this allow for a better understanding of microbial community ecology in marine systems, but this study will also provide insight into oxidative EET in a wide array of habitats, including marine and terrestrial subsurface environments and engineered environments where reduced electron sources are prevalent. From an applied and biotechnological standpoint, results from this work will enhance the capacity for evaluating microbe-electrode interactions in genetically tractable organisms, and may inform industrial applications of electrochemically active organisms, such as clean energy generation, wastewater treatment, and electrosynthesis.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

该奖项的全部或部分资金来源于《2021 年美国救援计划法案》（公法 117-2）。最近，人们发现一些微生物能够呼吸（“呼吸”）或获取能量（“进食”）细胞外电子转移（EET）促进了这一过程：一些微生物将电子从固体材料进出细胞的过程。 EET 可以在实验室环境中进行评估，其中微生物在电极上生长，并且可以测量生物电流（流入/流出电极的电子流）的产生。在这些实验中，电极处于特定电压。我们关于 EET 的大部分知识都是从几种能够进行呼吸矿物质还原的模型生物中获得的，其中电子从细胞转移到氧化固相材料上，例如氧化还原电位。如铁和然而，人们对氧化 EET 的机制或生态影响知之甚少，氧化 EET 是电子从还原矿物质转移到细胞作为能量来源（“吃”）的过程。微生物群落调查的证据表明，生活在各种栖息地（包括淡水和海洋环境）的生物体可能具有 EET 能力。该项目将扩展我们对氧化 EET 遗传基础的理解。此外，这些信息将深入了解 EET 在全球元素循环中的作用，并可能为使用电化学活性生物体的替代清洁能源发电、生物修复和废水处理工作提供信息。该项目将为本科生提供教育和培训机会，招募他们来协助研究任务，特别是在辛辛那提服务欠缺的地区，将组织为中学生提供实践教育机会。大约电微生物学和生物能源生产。细胞外电子转移 (EET) 的发现对于海洋地下沉积物中的一系列生物地球化学重要过程具有重要意义，其中微生物生物量估计占地球总生物量的 0.6%，即岩石营养代谢。由于氧化 EET 的遗传基础在很大程度上仍然未知且未表征，并且“组学”研究未能识别参与该过程的基因或蛋白质，因此很难检测到这一重要知识。差距，加上对“深海”和“暗海”海洋中微生物代谢的直接测量，大大超出了基于有机碳流入系统的预期模型，表明石营养代谢的重要性以及这些代谢的机制此外，对多微生物群落中 EET 的生态学了解甚少，但各种数据表明，多样化的微生物群落对于稳定和持续的环境功能非常重要。因此，该项目的总体目标是深入了解纯培养和共培养的两种遗传上易处理的电极氧化石营养海洋沉积物细菌中氧化过程中 EET 的遗传基础，以及这些过程的生态影响。将使用尖端的、有针对性的高通量测序技术来鉴定可能参与氧化 EET 的基因，以及在共培养物中促进种间电子转移的基因。将分析突变菌株的氧化 EET 和种间电子转移能力，这不仅可以更好地了解海洋系统中的微生物群落生态，而且这项研究还将深入了解各种栖息地的氧化 EET。 ，包括海洋和陆地地下环境以及普遍存在电子源减少的工程环境，从应用和生物技术的角度来看，这项工作的结果将增强从遗传角度评估微生物-电极相互作用的能力。该奖项是 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Physiologic, Genomic, and Electrochemical Characterization of Two Heterotrophic Marine Sediment Microbes from the Idiomarina Genus

Idiomarina 属两种异养海洋沉积物微生物的生理、基因组和电化学特征

• DOI: 10.3390/microorganisms10061219
• 发表时间: 2022-06-14
• 期刊: Microorganisms
• 影响因子: 4.5
• 作者: Vinales, Jorge;Sackett, Joshua;Trutschel, Leah;Amir, Waleed;Norman, Casey;Leach, Edmund;Wilbanks, Elizabeth;Rowe, Annette
• 通讯作者: Rowe, Annette

Genome-Scale Mutational Analysis of Cathode-Oxidizing Thioclava electrotropha ElOx9T

阴极氧化硫棒菌 ElOx9T 的基因组规模突变分析

• DOI: 10.3389/fmicb.2022.909824
• 发表时间: 2022
• 期刊: Frontiers in Microbiology
• 影响因子: 5.2
• 作者: Joshua D. Sackett;N. Kamble;E. Leach;Taruna A Schuelke;E. Wilbanks;A. Rowe
• 通讯作者: A. Rowe