Collaborative Research: Assessing the role of compound-specific phosphorus hydrolase transformations in the marine phosphorus cycle

合作研究：评估化合物特异性磷水解酶转化在海洋磷循环中的作用

• 批准号: 2001212
• 负责人: Solange Duhamel
• 金额: $ 49.98万
• 依托单位: University of Arizona
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-09-01 至 2022-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2001212&HistoricalAwards=false
• 关键词: Collaborative; Research; Assessing; role; compound

Phosphorus (P) is an essential building block for life. Because P is in short supply over vast areas of the ocean, P availability may control biological productivity, such as photosynthesis and carbon fixation, which has implications for uptake of the greenhouse gas carbon dioxide and thus climate regulation. Marine microorganisms must satisfy their nutritional requirement for P by obtaining it from seawater, where P is present in a variety of chemical forms, from simple phosphate ions (Pi) to complex dissolved organic phosphorus (DOP) molecules. The concentration of DOP vastly exceeds Pi over most ocean areas, therefore DOP is a critically important source of P for marine microbial nutrition and productivity. However, much remains unknown about the contribution of specific DOP compounds to the P nutrition, productivity, and structure of marine microbial communities. In this project, the investigators will conduct field experiments in the Atlantic Ocean and perform a series of controlled laboratory studies with pure enzymes and microbial cultures to determine how and to what extent different DOP compounds are degraded to Pi in the marine environment. Furthermore, the contribution of these compound-specific DOP molecules to microbial P nutrition, carbon fixation, and community structure will be determined, thus advancing the current state of knowledge regarding the factors that control the activity and distribution of microbial species in the ocean, and the ocean?s role in the climate system. This project will support two female junior investigators, a postdoctoral researcher, and graduate and undergraduate students. The undergraduate students will be recruited from the Marine Sciences program at Savannah State University, an Historically Black Colleges and Universities. In addition, results will be incorporated into new hands-on K-12 educational tools to teach students about microbial P biogeochemistry, including a digital game and formal lesson plans with hands-on demos. These tools will be validated with K-12 educators and will be widely accessible to the public through various well-known online platforms. These activities will thus reach a broad audience including a significant fraction of underrepresented groups.P is a vital nutrient for life. Marine microorganisms utilize P-hydrolases, such as alkaline phosphatase (AP), to release and acquire phosphate (Pi) from a wide diversity of dissolved organic P (DOP) compounds, including P-esters (P-O-C bonds), phosphonates (P-C), and polyphosphates (P-O-P). Compound-specific DOP transformations have the potential to exert critical and wide-ranging impacts on marine microbial ecology (e.g. variable DOP bioavailability among species), biogeochemistry (e.g. P geologic sequestration via formation of calcium Pi), and global climate (e.g. aerobic production of the greenhouse gas methane by dephosphorylation of methylphosphonate). However, the mechanisms and comparative magnitude of specific DOP transformations, in addition to their relative contributions to microbial community-level P demand, productivity, and structure, are not completely understood. This study will fill these knowledge gaps by tracking the fate of specific DOP pools in the marine environment. Specifically, this project will test four hypotheses in the laboratory using recombinant enzymes and axenic cultures representative of marine eukaryotic and prokaryotic plankton from high and low nutrient environments, and in the field using observational and experimental approaches along natural Pi gradients in the Atlantic Ocean. In particular, the investigators will reveal potential differences in the hydrolysis and utilization of specific DOP compounds at the community- (bulk enzymatic assays), taxon- (cell sorting of radiolabeled cells in natural samples), species- (axenic cultures) and molecular-levels (pure enzyme kinetic studies and cell-associated proteomes and exoproteomes). Results from our proposed work will provide a robust understanding of the enzymatic basis involved in the transformation of specific forms of DOP and create new knowledge on the relative contribution of these specific P sources to Pi production, marine microbial nutrition, community structure, primary productivity, and thus global carbon cycling and climate. In particular, our refined measurements of the concentration of bioavailable DOP and our unique estimates of DOP remineralization fluxes will provide critical new information to improve models of marine primary production and P cycling.

磷（P）是生命的重要组成部分。 由于磷在海洋的广大地区供应短缺，磷的可用性可能会控制生物生产力，如光合作用和碳固定，这对温室气体二氧化碳的吸收和气候调节有影响。 海洋微生物必须通过从海水中获得磷来满足其对磷的营养需求，其中磷以各种化学形式存在，从简单的磷酸根离子（Pi）到复杂的溶解有机磷（DOP）分子。 在大多数海洋区域，DOP的浓度远远超过Pi，因此DOP是海洋微生物营养和生产力的关键重要P源。然而，仍有很多未知的具体DOP化合物的P营养，生产力和海洋微生物群落结构的贡献。 在该项目中，研究人员将在大西洋进行实地实验，并使用纯酶和微生物培养物进行一系列受控实验室研究，以确定不同DOP化合物在海洋环境中如何以及在多大程度上降解为Pi。 此外，这些化合物的具体DOP分子对微生物的磷营养，固碳和社区结构的贡献将被确定，从而推进目前的知识状态有关的因素，控制的活动和分布的微生物物种在海洋中，和海洋？在气候系统中的作用。 该项目将支持两名女性初级研究员，一名博士后研究员，以及研究生和本科生。 本科生将从萨凡纳州立大学的海洋科学项目中招募，这是一所历史上的黑人学院和大学。 此外，研究结果将被纳入新的实践K-12教育工具，向学生传授微生物磷地球化学，包括数字游戏和带有实践演示的正式课程计划。这些工具将与K-12教育工作者进行验证，并将通过各种知名的在线平台向公众广泛提供。因此，这些活动将覆盖广泛的受众，包括很大一部分代表性不足的群体。 海洋微生物利用P-水解酶（如碱性磷酸酶（AP））从多种溶解的有机P（DOP）化合物（包括P-酯（P-O-C键）、膦酸酯（P-C）和多磷酸盐（P-O-P））中释放和获取磷酸盐（Pi）。特定化合物的DOP转化有可能对海洋微生物生态学（例如，不同物种之间DOP的生物利用度）、海洋地球化学（例如，通过形成钙Pi的磷地质封存）和全球气候（例如，通过甲基膦酸盐的去磷酸化产生温室气体甲烷的有氧生产）产生关键和广泛的影响。然而，具体DOP转换的机制和比较幅度，除了他们的相对贡献微生物群落水平的磷需求，生产力和结构，还没有完全理解。这项研究将通过跟踪海洋环境中特定DOP池的命运来填补这些知识空白。具体而言，该项目将测试四个假设在实验室中使用重组酶和纯培养物代表海洋真核和原核浮游生物从高和低营养环境，并在现场使用观测和实验方法沿着自然Pi梯度在大西洋。特别是，研究人员将揭示特定DOP化合物在社区（批量酶测定），分类群（天然样品中放射性标记细胞的细胞分选），物种（纯培养物）和分子水平（纯酶动力学研究和细胞相关蛋白质组和外蛋白质组）的水解和利用的潜在差异。 从我们提出的工作的结果将提供一个强大的了解参与特定形式的DOP的转化酶的基础上，创造新的知识，这些特定的磷源的相对贡献Pi生产，海洋微生物营养，社区结构，初级生产力，从而全球碳循环和气候。特别是，我们对生物可利用DOP浓度的精确测量和我们对DOP矿化通量的独特估计将为改进海洋初级生产和P循环模型提供关键的新信息。

项目成果

Contrasting Roles of DOP as a Source of Phosphorus and Energy for Marine Diazotrophs

DOP 作为海洋固氮生物磷源和能源的对比作用

• DOI: 10.3389/fmars.2022.923765
• 发表时间: 2022
• 期刊: Frontiers in Marine Science
• 影响因子: 3.7
• 作者: Filella, Alba;Riemann, Lasse;Van Wambeke, France;Pulido-Villena, Elvira;Vogts, Angela;Bonnet, Sophie;Grosso, Olivier;Diaz, Julia M.;Duhamel, Solange;Benavides, Mar
• 通讯作者: Benavides, Mar

Dissolved Organic Phosphorus Utilization by Phytoplankton Reveals Preferential Degradation of Polyphosphates Over Phosphomonoesters

• DOI: 10.3389/fmars.2018.00380
• 发表时间: 2018-10-25
• 期刊: FRONTIERS IN MARINE SCIENCE
• 影响因子: 3.7
• 作者: Diaz, Julia M.;Holland, Alisia;Duhamel, Solange
• 通讯作者: Duhamel, Solange

How microbes in Iceland can teach us about possible life on Mars

冰岛的微生物如何让我们了解火星上可能存在的生命

• DOI: 10.33424/futurum112
• 发表时间: 2021
• 期刊: Futurum
• 作者: Duhamel, Solange;Hamilton, Christopher
• 通讯作者: Hamilton, Christopher

Preferential utilization of inorganic polyphosphate over other bioavailable phosphorus sources by the model diatoms Thalassiosira spp.

模型硅藻 Thalassiosira spp 优先利用无机多磷酸盐而不是其他生物可利用的磷源。

• DOI: 10.1111/1462
• 发表时间: 2019
• 期刊: Environmental Microbiology
• 影响因子: 5.1
• 作者: Diaz, Julia M.;Steffen, Rachel;Sanders, James G.;Tang, Yuanzhi;Duhamel, Solange
• 通讯作者: Duhamel, Solange