Waterborne chemical cues in the plankton: a systems biology approach

浮游生物中的水性化学线索：系统​​生物学方法

• 批准号: 1060300
• 负责人: Julia Kubanek
• 金额: $ 54.59万
• 依托单位: Georgia Tech Research Corporation
• 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: 2011-10-01 至 2015-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1060300&HistoricalAwards=false
• 关键词: Waterborne; chemical; cues; plankton; systems

Intellectual merit: Competition is a major force structuring communities, including the marine plankton. The release of compounds that inhibit competitors, a process known as allelopathy, is hypothesized to be important among phytoplankton, especially for species that compete poorly for resources yet form dense blooms. Ecological interactions involving the toxic red tide dinoflagellate Karenia brevis present an ideal system for understanding chemically mediated interactions. Blooms of this species occur frequently in accessible coastal areas of the Gulf of Mexico, causing massive fish kills and contaminating shellfish. The dramatic consequences of these blooms motivate the following questions. What strategies does this harmful alga use in competition with other phytoplankton? What lethal and sub-lethal effects are experienced by competitors? How do phytoplankton respond, resist, and detoxify their surroundings? What roles do chemical cues play in these interactions? How are different phytoplankton communities affected by allelopathy? Previous studies have shown that K. brevis is allelopathic to several naturally co-occurring phytoplankton species, but compounds other than the known neurotoxic brevetoxins produced by K. brevis generally were responsible. This species produces allelopathic mixtures of unstable, 500-1000 Da organic compounds which cause reduced photosystem II activity and disrupt cell membranes of sensitive species, whereas some other competitors remain unaffected. Moreover, natural blooms of K. brevis were allelopathic to the competing diatom Skeletonema grethae. This species, in turn, appeared to influence the chemistry of K. brevis, reducing its allelopathic effects. Death is a rare outcome of K. brevis allelopathy; more subtle, non-lethal responses have predominated. Overall, environmental context may be critical for predicting what ecologically important chemical mediators are released into marine systems and the consequences of these compounds to plankton communities. The project will: 1) Characterize the exudate metabolome among K. brevis samples of varying allelopathic potency. Exudates of K. brevis strains and natural bloom samples will be studied by mass spectrometry (MS) and nuclear magnetic resonance (NMR) metabolomics to pinpoint candidate chemical cues involved in competition. Karenia brevis protein expression will be examined by MS proteomics to test whether K. brevis up- or down-regulates key proteins involved in pathway networks in response to challenges by competitors. 2) Seek to understand sub-lethal metabolic impacts of exposure to allelopathy on target phytoplankton, by studying responses of phytoplankton to K. brevis allelopathy by MS-based metabolomics and proteomics. This work will provide an unbiased approach to determining molecular targets of allelopathy and allow testing of whether sub-lethal responses to allelopathy include suppressed fundamental cellular functioning and up-regulated pathways related to stress and detoxification. 3) Relate allelopathic sensitivity to metabolic responses in target phytoplankton, by comparing metabolomic and proteomic changes of sensitive versus resistant competitors to K. brevis allelopathy. The expectation is that more resistant species experience enhancement of detoxification pathways and more robust, unaffected cellular function relative to competitors most sensitive to allelopathy. 4) Determine how estuarine and off-shore phytoplankton differ in their physiological responses to allelopathy, because allelopathy may be more important for maintaining dense blooms in near-shore waters than in the initiation of blooms off-shore. Broader impacts: Phytoplankton blooms can be devastating to local economies and pose human health risks. The discovery of new chemically mediated interactions and metabolic responses in the marine plankton could eventually lead to prediction and control strategies to alleviate the harmful consequences of these blooms. Continued effort to characterize mixtures of allelopathic compounds and determine their effects on competing species could lead to biodegradable treatments for reducing phytoplankton or microbial growth in aquatic and terrestrial environments. This study builds on past successes, applying lessons learned from chemistry about ecological processes and using ecological insights to discover unique natural products with important biological functions. This project will provide training for 3 PhD students and several undergraduates. The PhD students will expand their roles in previous educational training activities, participating in a "Tech for Teaching" program that places Georgia Tech students in Atlanta-area public high schools with ~99% minority students. These African-American students will learn about the question-asking nature of science and issues surrounding red tides in the U.S., as well as associated connections to human impacts on marine environments, exciting them about science by connecting it with their daily lives.

智力优势：竞争是构建群落的主要力量，包括海洋浮游生物。抑制竞争者的化合物的释放，一个被称为化感作用的过程，被假设在浮游植物中是重要的，特别是对于那些对资源竞争很差但形成密集水华的物种。有毒赤潮甲藻Karenia brevis的生态相互作用为理解化学介导的相互作用提供了一个理想的系统。该物种的大量繁殖经常发生在墨西哥湾可进入的沿海地区，造成大量鱼类死亡和贝类污染。这些水华的戏剧性后果引发了以下问题。这种有害的浮游植物在与其他浮游植物的竞争中使用什么策略？竞争对手经历了哪些致命和亚致命影响？浮游植物如何应对，抵抗和解毒他们的环境？化学信号在这些相互作用中扮演什么角色？不同的浮游植物群落如何受到化感作用的影响？以往的研究表明，K。brevis对几种自然共存的浮游植物具有化感作用，但除了已知的由K.一般来说，brevis是负责的。该物种产生不稳定的500-1000 Da有机化合物的化感混合物，其导致光系统II活性降低并破坏敏感物种的细胞膜，而一些其他竞争者不受影响。此外，K.短体对竞争硅藻Grethae具有化感作用。反过来，这种物种似乎影响了K的化学性质。brevis，降低其化感作用。死亡是K的罕见结果。短化感作用;更微妙的，非致命的反应占主导地位。总体而言，环境背景可能是至关重要的预测生态重要的化学介质释放到海洋系统和这些化合物的浮游生物群落的后果。本项目将：1）研究K.不同的化感作用的样品。K.将通过质谱法（MS）和核磁共振（NMR）代谢组学研究brevis菌株和天然水华样品，以查明参与竞争的候选化学线索。利用MS蛋白质组学技术检测短凯伦藻蛋白质的表达情况，以验证短凯伦藻是否具有生物学活性。brevis上调或下调参与途径网络的关键蛋白质，以响应竞争对手的挑战。2)通过研究浮游植物对钾的响应，了解化感作用对目标浮游植物亚致死代谢的影响。利用MS代谢组学和蛋白质组学技术对短叶薯蓣化感作用的研究进展。这项工作将提供一个公正的方法来确定化感作用的分子靶点，并允许测试化感作用的亚致死反应是否包括抑制基本细胞功能和上调与应激和解毒相关的途径。3)通过比较敏感与抗性竞争对手的代谢组学和蛋白质组学变化，将化感作用敏感性与目标浮游植物的代谢反应联系起来。化感作用期望的是，更多的抗性物种经历增强解毒途径和更强大的，不受影响的细胞功能相对于竞争对手最敏感的化感作用。4)确定如何河口和近海浮游植物不同的生理反应，化感作用，因为化感作用可能是更重要的维持密集的水华在近岸沃茨比在启动水华离岸。更广泛的影响：浮游植物大量繁殖可能对当地经济造成破坏，并对人类健康构成威胁。海洋浮游生物中新的化学介导的相互作用和代谢反应的发现可能最终导致预测和控制策略，以减轻这些水华的有害后果。继续努力表征化感化合物的混合物，并确定其对竞争物种的影响，可能会导致生物可降解的处理，减少浮游植物或微生物在水生和陆地环境中的生长。这项研究建立在过去的成功基础上，应用化学关于生态过程的经验教训，并利用生态学的见解来发现具有重要生物功能的独特天然产物。该项目将为3名博士生和几名本科生提供培训。博士生将扩大他们在以前的教育培训活动中的作用，参加一个“技术教学”计划，该计划将格鲁吉亚技术学生安置在少数民族学生占99%的亚特兰大地区公立高中。这些非洲裔美国学生将了解科学的提问性质和美国赤潮问题，以及人类对海洋环境影响的相关联系，通过将科学与他们的日常生活联系起来，使他们对科学感到兴奋。