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

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，特别是对于最小的浮游微生物来说。 不仅较小的生物有时会吃较大的生物，而且越来越多的证据表明化学信号和防御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个紧急属性的中心前提，对上层海洋浮游植物细胞生活的几乎每个方面都有影响。氧化应激（OS），由许多环境应激源引起，可损伤细胞并导致释放被怀疑是调节原生生物行为的有效信号的化合物。通过化学信号，OS被假设为管理环境变化，浮游植物状况和原生生物捕食之间的关系。这些综合过程的研究有三个首要目标：1）使用光应力在实验室中创建氧化应激浮游植物，并使用一系列荧光探针，生化测量和生理测定来表征响应。此外，将量化潜在信号分子的产生和释放。2)研究原生生物捕食和行为反应氧化强调浮游植物和相关的化学信号。响应将通过操作实验和产生的信号化学进行研究。3)调查OS的患病率，其环境相关性，和微型浮游动物捕食反应在当地海湾。更广泛的影响将直接建立在这些实验和观测活动之上。该项目将通过香农角海洋中心的两个项目，包括一个针对代表性不足的少数民族的项目，支持几名研究生和本科生。资金将支持大量的异养原生生物分离物的收集。荧光计将用于开发至少3个不同的西方华盛顿大学海洋相关课程的新单位。此外，研究生将使用原生生物图像作为基础，针对普通公众和K-12学生的外展活动。这项研究将有助于阐明OS响应可以影响浮游植物健身的许多方式中的一些，表征关键沿海物种的位置沿着OS响应谱。这些发现也将为相对较新和令人兴奋的化学信号领域提供信息。最后，这项研究将有助于阐明环境胁迫，浮游植物的反应，捕食在浮游生态系统之间的联系。这些联系涉及生物海洋学的核心问题，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奋进，通过一个新颖的概念框架将通常孤立研究的主题结合起来。结果有可能产生广泛适用的见解，这一关键营养环节的生态和进化调控的浮游食物网。

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.