Collaborative Research: Biological production of reactive oxygen species in freshwaters

智力优势：活性氧物种(ROS)、超氧化物、过氧化氢和羟基，可以对水生系统中金属和有机化合物的循环产生重大影响。虽然已知真菌、藻类和细菌都能产生胞外ROS，但人们普遍认为，与天然有机物的光氧化相比，淡水系统中生物ROS的产生可以忽略不计。然而，来自Voelker实验室的最新结果表明，暗生物产生过氧化氢比光化学产生更重要。这项研究的总体目标是阐明淡水系统中ROS产生的生物学作用。具体目标是确定哪些类型的生物是淡水系统中活性氧物种的重要来源，哪些环境变量影响ROS的产生速率，以及哪些生物地球化学过程可能受到生物ROS产生的影响。PIs将侧重于三个假设：(I)ROS的生物生产是普遍存在的，特定的微生物群(可能是细菌、藻类或真菌)是造成这种现象的原因。(2)特定生物体的生物生产率可能会因环境条件的变化而改变，例如可利用的营养物质和光照强度。(3)超氧化物和芬顿产物是生物产生ROS的结果，其速率足以影响有机化合物和金属的循环。PIs将在选定的田野地点培养和隔离负责产生ROS的微生物，目标是藻类、细菌和/或真菌群。然后，PI将利用他们在栽培有机体上的工作来设计分子技术，以检查生物体自然组合的ROS产生率之间的关系。更广泛的影响。拟议的工作将为几名研究生和本科生提供教育机会。私人投资机构在为少数族裔和妇女提供咨询方面有着良好的记录，这项提议的招生工作将继续侧重于科学和工程领域代表性不足的群体。此外，PIS将利用这项研究的结果，就微生物在产生活性氧物种中的作用及其对微生物生态系统和水生生物地球化学健康的影响开展一系列讲座。专业人士将在一年一度的科学教育工作者专业发展研讨会上发表演讲，主题为？无形世界之窗？由哈佛大学微生物科学倡议组织协调。

Intellectual merit: The reactive oxygen species (ROS), superoxide, hydrogen peroxide, and hydroxyl, can have significant effects on the cycling of metals and organic compounds in aquatic systems. Although it is known that fungi, algae and bacteria are all capable of extracellular ROS production, it has generally been assumed that biological ROS production is negligible in freshwater systems, compared to photo-oxidation of natural organic matter. However, recent results from the Voelker lab indicate that dark biological production of H2O2 is more important than photochemical production. The overall goal of this research is to elucidate the biological role in ROS production in freshwater systems. The specific objectives are to determine which types of organisms are significant sources of reactive oxygen species to freshwater systems, which environmental variables affect ROS production rates, and which biogeochemical processes are likely to be affected by biological ROS production. The PIs will focus on three hypotheses: (i) Biological production of ROS is widespread, and specific microbial groups (which may be bacterial, algal or fungal) are responsible. (ii) Biological production rates by a specific organism can change as a result of changes in the environmental conditions such as available nutrients and light intensity. (iii) Superoxide and Fenton products are generated as a result of biological ROS production, at rates sufficient to affect the cycling of organic compounds and metals. The PIs will cultivate and isolate organisms responsible for ROS production at selected field sites, targeting algal, bacterial, and/or fungal groups. The PIs will then use their work on the cultivated organisms to design molecular techniques to examine the relationship between ROS production rates by natural assemblages of organisms. Broader Impacts. The proposed work will provide an educational opportunity for several graduate students and undergraduates. The PIs have a strong track record in advising minorities and women, and student recruitment efforts for this proposal will continue to be focused on underrepresented groups in science and engineering. In addition, the PIs will draw on the results of this research to develop a series of lectures on the role of microorganisms in the production of reactive oxygen species and their impact on the health of microbial ecosystems and aquatic biogeochemistry. The PIs will present the lectures at the annual Professional Development Workshop for Science Educators entitled ?Windows on the Invisible World? coordinated by the Microbial Sciences Initiative at Harvard University.