Environmental stress and signaling based on reactive oxygen species among planktonic protists

基于浮游原生生物活性氧的环境应激和信号传导

• 批准号: 1434842
• 负责人: Suzanne Strom
• 金额: $ 59.96万
• 依托单位: Western Washington University
• 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: 2014-09-01 至 2020-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1434842&HistoricalAwards=false
• 关键词: Environmental; stress; signaling; based; reactive

Traditionally marine food webs have been studied on the basis of size, assuming that larger organisms eat smaller ones, and that they eat everything in a given size range. This simplification has not stood the test of time, especially for the smallest microbial plankton. Not only do smaller organisms sometimes eat larger ones, there is growing evidence that chemical signaling and defenses are acting at these small scales. This project addresses the central premise that the oxidative stress response is an emergent property of phototrophic cellular systems, with implications for nearly every aspect of a phytoplankton cell's life in the upper ocean. Oxidative stress (OS), arising from numerous environmental stressors, can damage cells and lead to release of compounds suspected to be potent signals regulating protist behavior. Through chemical signaling, OS is hypothesized to govern relationships among environmental variability, phytoplankton condition, and protist predation. The study of these integrated processes has three overarching objectives: 1) Use light stress to create oxidatively stressed phytoplankton in the laboratory, and characterize the response using an array of fluorescent probes, biochemical measurements, and physiological assays. In addition, production and release of potential signal molecules will be quantified. 2) Examine protist predation and behavioral responses to oxidatively stressed phytoplankton and associated chemical signals. Responses will be investigated by means of manipulation experiments and resulting signal chemistry. 3) Investigate the prevalence of OS, its environmental correlates, and the microzooplankton predation response in a local embayment. Broader impacts will build directly on these experimental and observational activities. The project will support several graduate students and involve undergraduates through two programs at Shannon Point Marine Center, including one targeting under-represented minorities. Funds will support a significant collection of heterotrophic protists isolates. The fluorometer will be used in developing new units for at least 3 different Western Washington University marine-related courses. In addition, graduate students will use protist images as the basis for outreach activities aimed at the general public and K-12 students.This research will help to elucidate some of the many ways in which the OS response can affect phytoplankton fitness, characterizing the position of key coastal species along an OS response spectrum. Findings will also inform the relatively new and exciting field of chemical signaling in planktonic communities. Finally, this study will help elucidate the links between environmental stress, phytoplankton response, and predation in planktonic ecosystems. These links relate to central issues in biological oceanography, including the predator-prey interactions that influence bloom demise, and the mechanisms by which protists feed selectively and thereby structure prey communities. The research is a cross-cutting endeavor that unites subjects usually studied in isolation through a novel conceptual framework. Outcomes have the potential to generate broadly applicable insights into the ecological and evolutionary regulation of this key trophic link in planktonic food webs.

传统上，海洋食物网是根据大小来研究的，假设较大的生物吃较小的生物，并且它们吃给定大小范围内的所有东西。这种简化并没有经受住时间的考验，尤其是对于最小的浮游微生物而言。不仅较小的生物有时会吃掉较大的生物，而且越来越多的证据表明，化学信号和防御也在这些小尺度上起作用。该项目解决了氧化应激反应是光养细胞系统的一种紧急特性这一中心前提，其影响几乎涉及海洋上层浮游植物细胞生命的每一个方面。氧化应激（OS）是由多种环境应激源引起的，它可以损伤细胞并导致化合物的释放，这些化合物被怀疑是调节原生生物行为的有效信号。通过化学信号，OS被假设控制环境变异性、浮游植物状况和原生生物捕食之间的关系。对这些综合过程的研究有三个主要目标：1)在实验室中利用光胁迫产生氧化应激浮游植物，并使用一系列荧光探针、生化测量和生理分析来表征这种反应。此外，潜在信号分子的产生和释放将被量化。2)研究原生生物对氧化应激浮游植物的捕食和行为反应以及相关的化学信号。反应将通过操作实验和由此产生的信号化学来研究。3)调查局部海湾中OS的流行、环境相关因素以及浮游动物捕食反应。更广泛的影响将直接建立在这些实验和观测活动上。该项目将通过香农角海洋中心的两个项目为几名研究生和本科生提供支持，其中一个项目针对代表性不足的少数族裔。资金将支持大量收集异养原生生物分离物。该荧光计将用于为西华盛顿大学至少3门不同的海洋相关课程开发新的单元。此外，研究生将使用原生图像作为针对普通公众和K-12学生的外展活动的基础。这项研究将有助于阐明生态系统响应影响浮游植物适应性的许多方式，并描述关键沿海物种在生态系统响应谱上的位置。研究结果还将为浮游生物群落中化学信号传导这一相对较新的令人兴奋的领域提供信息。最后，本研究将有助于阐明浮游生态系统中环境胁迫、浮游植物反应和捕食之间的联系。这些联系与生物海洋学的核心问题有关，包括影响水华消亡的捕食者-猎物相互作用，以及原生生物选择性进食从而构建猎物群落的机制。这项研究是一项跨领域的努力，通过一个新的概念框架，将通常孤立研究的学科联系起来。结果有可能对浮游食物网中这一关键营养环节的生态和进化调控产生广泛适用的见解。