Membrane vesicles produced by marine bacteria: origins, distributions, and functions

海洋细菌产生的膜囊泡：起源、分布和功能

• 批准号: 1356460
• 负责人: Sallie Chisholm
• 金额: $ 59.92万
• 依托单位: Massachusetts Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-02-01 至 2019-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1356460&HistoricalAwards=false
• 关键词: Membrane; vesicles; produced; marine; bacteria

Overview: Some bacteria are known to release small amounts of their cell envelope in the form of tiny ( 200 nm diameter) spherical structures known as membrane vesicles. While the functions of these vesicles have been explored in pathogens, nothing is known about their abundance or roles in marine ecosystems. The investigators have recently demonstrated that Prochlorococcus, the numerically dominant photosynthetic cell in the world's oceans releases membrane vesicles continually during growth, and they have shown that these structures are indeed found in abundance in ocean samples. Bacterially produced membrane vesicles represent a major new feature of ocean ecosystems and could provide important clues about the network of interactions among microbes and their environment. Prochlorococcus vesicles contain diverse macromolecules, including lipids, proteins, and nucleic acids, suggesting that these structures could play many varied roles within marine microbial communities. The researchers will use the Prochlorococcus model system and the analysis of natural seawater samples from several field sites to address fundamental questions about the production and function of membrane vesicles in the oceans. The overarching questions motivating this study include: What environmental factors influence the rate of release of membrane vesicles by Prochlorococcus, and what can this tell us about the regulation of this process? How does vesicle abundance vary in different regions of the oceans? What DNA is found in vesicles from natural seawater samples? How does the vesicle "metagenome" compare to the bacterial metagenome, and what can this tell us about the diversity of organisms that release vesicles? What ecological roles might vesicles play in marine microbial ecosystems? Can they facilitate horizontal gene transfer? Can they act as a "decoy" to reduce phage predation?Intellectual Merit: Membrane vesicles represent a major new feature in ocean ecosystems. These discrete, organized structures may influence a number of biogeochemical processes, including horizontal gene transfer; moving small molecules, proteins or other macromolecules between cells; or serving as a source of fixed carbon for other bacteria. Yet we know nothing about them. This project will open this black box, and help us begin to understand the abundance and sources of membrane vesicles in the oceans, determine factors affecting their production by the numerically dominant photoautotroph Prochlorococcus, and explore aspects of their ecological roles in marine systems. With this research, the investigators will begin to establish a new area of study in marine microbial ecology that has the potential to alter current paradigms about the mechanisms through which microbes interact with both their biotic and abiotic environment.Broader Impacts: The investigators will take advantage of several avenues available at MIT to work with under-represented groups. These include: the MIT Summer Research Program, CONVERGE (a preview weekend); SEED (a Saturday education program); KEYs (a program for girls), and the MIT Edgerton Center which facilitates visits from local K-12 classes. The investigator is committed to communicating science to broad audiences. The PI has published two children's books on photosynthesis (Living Sunlight, Ocean Sunlight, Scholastic 2009, 2012; both received "best children's picture book" awards from AAAS), and is currently working on a third, on fossil fuels and climate, which will appear in 2014. This project will play a central role in the professional development of the post-doc(s) involved and data resulting from the proposed activity will be posted on public web sites, including the Prochlorococcus Portal (http://proportal.mit.edu/), and the Vesiclepedia database (http://www.microvesicles.org)

概述：已知一些细菌以微小（200 nm）球形结构的形式释放出少量的细胞包膜，称为膜囊泡。尽管这些囊泡的功能已经在病原体中探讨了，但对它们在海洋生态系统中的丰度或角色尚无知之甚少。研究人员最近表明，二氯环球菌是世界海洋上数值主导的光合细胞，在生长过程中不断释放膜囊泡，它们表明这些结构确实在海洋样品中有丰度发现。细菌产生的膜囊泡代表了海洋生态系统的主要新特征，可以提供有关微生物及其环境之间相互作用网络的重要线索。核球菌囊泡包含多种大分子，包括脂质，蛋白质和核酸，表明这些结构可以在海洋微生物群落中起许多不同的作用。研究人员将使用Prochlorococus模型系统以及对几个现场的天然海水样品的分析来解决有关海洋中膜囊泡的生产和功能的基本问题。促使这项研究的总体问题包括：哪些环境因素会影响甲氯环球菌的膜囊泡的释放速率，这可以告诉我们有关此过程的调节的何种情况？囊泡丰度在海洋的不同区域如何变化？来自天然海水样品的囊泡中发现了哪些DNA？囊泡“元基因组”与细菌元基因组相比如何，这可以告诉我们释放囊泡的生物多样性？囊泡在海洋微生物生态系统中可能起什么生态作用？它们可以促进水平基因转移吗？他们可以充当减少噬菌体捕食的“诱饵”吗？智力优点：膜囊泡代表了海洋生态系统中的主要新特征。这些离散的组织结构可能会影响许多生物地球化学过程，包括水平基因转移。移动细胞之间的小分子，蛋白质或其他大分子；或作为其他细菌的固定碳的来源。但是我们对他们一无所知。该项目将打开这个黑匣子，并帮助我们开始了解海洋中膜囊泡的丰度和来源，确定因数值主导的光自足型核球菌影响其生产的因素，并探索其在海洋系统中生态角色的各个方面。 通过这项研究，研究人员将开始建立一个新的海洋微生物生态研究领域，该研究有可能改变当前的范式，以了解微生物与其生物和非生物环境相互作用的机制。Boader的影响：研究人员将利用MIT可用的几种途径与不足的组合群体一起使用。其中包括：麻省理工学院夏季研究计划，汇聚（预览周末）；种子（星期六教育计划）； Keys（女孩计划）和MIT Edgerton中心，可促进当地K-12班的访问。研究人员致力于向广泛的受众传达科学。 PI已经出版了两本有关光合作用的儿童读物（活阳光，海洋阳光，2009，2012；均获得了来自AAAS的“最佳儿童图画书”奖），目前正在从事第三份工作，从事化石燃料和气候，该项目将在2014年出现。该项目将在公开范围内发挥作用，并在公开范围内发挥作用，并在涉及后的数据中发挥了作用。 ProChlorococcus Portal（http://proportal.mit.edu/）和vesiclepedia数据库（http://www.microvesicles.org）