EAGER: Tracking marine diazotrophy with isotope-labeling proteomics

EAGER：利用同位素标记蛋白质组学追踪海洋固氮营养

• 批准号: 2050685
• 负责人: Jacob Waldbauer
• 金额: $ 29.96万
• 依托单位: University of Chicago
• 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: 2021-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2050685&HistoricalAwards=false
• 关键词: EAGER; Tracking; marine; diazotrophy; isotope

Throughout much of the global ocean, nitrogen fixation – the conversion of abundant atmospheric nitrogen gas into chemical forms usable by life – is a crucial source of nutrients for biological activity. In particular, life needs nitrogen to make proteins, the essential biochemical machines that power all cells. Nitrogen fixation in the oceans is carried out by a variety of microorganisms, whose surprising diversity and ecology oceanographers are working to uncover. This project uses a novel mass spectrometry technique to directly track the flow of nitrogen from nitrogen gas, via nitrogen fixation, into proteins. These measurements reveal which nitrogen-fixing organisms are active in a given part of the ocean, what proteins they make with the nitrogen they fix, and how that nitrogen ultimately flows to feed the entire marine biological community. This information will better inform models and predictions of how marine microbial ecosystems, and the essential biogeochemistry they perform, responds to changing conditions in the ocean. This project engages an undergraduate student researcher, recruited from groups underrepresented in science, in both the field and laboratory work.Diazotrophy (biological N2 fixation) is the largest input of fixed nitrogen to the ocean and is carried out by a wide diversity of marine microbes, but we have limited ability to quantify the N2-fixation activity of the full diversity of marine diazotrophs, or to resolve how the N they fix ultimately flows to supply the broader microbial community. Since the primary biosynthetic fate of fixed N2 is protein production, proteomics is poised to make substantial contributions to our understanding of the marine nitrogen cycle, and to the molecular physiology and ecological roles of diazotrophs in particular. This project brings a novel 15N-tracking proteomics methodology to bear on three outstanding questions in marine diazotroph ecology:1) How is whole-community N2 fixation activity apportioned among different diazotroph taxa?2) How do diazotrophs and their symbiotic partners make biosynthetic use of the N they fix?3) How much diazotroph-derived N is redistributed to particular non-diazotroph taxa?The investigators are conducting 15N2-tracking proteomics experiments at the Hawaii Ocean Time-series (HOT) Station ALOHA, assaying N incorporation from 15N-labeled dinitrogen into proteins of both diazotrophs and the broader microbial community. This is the first use of proteomics to track diazotrophic 15N2 incorporation, representing a novel, molecular-level approach for investigating marine nitrogen fixation that encompasses the entire microbial community with high taxonomic resolution. 15N-tracking proteomics data provides unique insight into the flow of nitrogen currency through its key biological accounts in cellular proteomes, and into the ecophysiology and biogeochemical roles of marine diazotrophs.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.

在全球大部分海洋中，固氮作用（将大气中丰富的氮气转化为生命可用的化学形式）是生物活动的重要营养来源。特别是，生命需要氮来制造蛋白质，蛋白质是为所有细胞提供动力的重要生化机器。海洋中的固氮是由多种微生物进行的，海洋学家正在努力揭示其令人惊讶的多样性和生态学。该项目使用一种新颖的质谱技术来直接跟踪氮气中的氮气通过固氮作用进入蛋白质的流动。这些测量揭示了哪些固氮生物体在海洋的特定区域中活跃，它们用固氮产生哪些蛋白质，以及氮最终如何流动以养活整个海洋生物群落。这些信息将更好地为海洋微生物生态系统及其所执行的基本生物地球化学如何响应海洋条件变化的模型和预测提供信息。该项目聘请了一名本科生研究员，他们是从科学领域中代表性不足的群体中招募的，从事现场和实验室工作。固氮生物（生物固氮）是海洋固定氮的最大输入，是由多种海洋微生物进行的，但我们量化全部海洋固氮生物多样性的固氮活性的能力有限，或者解决如何解决海洋固氮生物的问题。 他们最终修复流量以供应更广泛的微生物群落。由于固定氮的主要生物合成命运是蛋白质生产，因此蛋白质组学将为我们了解海洋氮循环，特别是固氮生物的分子生理学和生态作用做出重大贡献。该项目带来了一种新颖的 15N 跟踪蛋白质组学方法，用于解决海洋固氮生物生态学中的三个突出问题：1）整个群落的 N2 固定活性如何在不同的固氮生物类群之间分配？2）固氮生物及其共生伙伴如何对它们固定的 N 进行生物合成利用？3）有多少固氮生物衍生的 N 被重新分配给特定的固氮生物 研究人员正在夏威夷海洋时间序列 (HOT) 站 ALOHA 进行 15N2 跟踪蛋白质组学实验，分析 15N 标记的二氮与固氮生物和更广泛的微生物群落蛋白质中的 N 结合情况。这是蛋白质组学首次用于追踪固氮 15N2 掺入，代表了一种新颖的分子水平方法，用于研究海洋固氮，该方法以高分类分辨率涵盖整个微生物群落。 15N 跟踪蛋白质组学数据通过细胞蛋白质组中的关键生物帐户提供了对氮货币流动的独特见解，以及海洋固氮生物的生态生理学和生物地球化学作用。该奖项反映了 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。