Copper Metabolism in Marine Synechococcus

痕量金属样品的处理和分析导致发现，铁等微小(纳摩尔)水平的金属正在对海洋初级生产者的多样性、丰度和碳固定产生深远影响。这些重要初级生产者之一--海洋蓝藻--同样受到铜(自然和人为)水平的积极和消极影响，也可能受到钴和镍水平的影响。与此同时，蓝藻和其他浮游植物正在通过吸收改变金属的分布及其反应活性，这导致地表水中金属的可测量耗尽，并通过细胞外产生金属结合配体。由于铜在水生环境中的重要性，PI将使用来自寡营养环境和沿海环境的模型聚球藻菌株来表征海洋蓝藻中的铜代谢，这些菌株具有由全基因组测序项目揭示的截然不同的金属生理。他们将使用探测细胞全球反应的全基因组微阵列来表征菌株如何对不同的铜水平做出反应，并将这些研究与细胞内金属水平的最新表征以及其他细胞生理和光合作用能力的测量相结合。将对不同的铜相关基因进行分子遗传学研究，以确定它们在细胞中的功能。初步结果发现了一个潜在的候选细胞内铜结合蛋白，该蛋白在所有海洋蓝藻中都是保守的。与此同时，初步结果发现，沿海蓝藻对铜的抵抗力强于远洋物种，这可能是由于一种新的铜结合或外排系统。PI将通过开发动手实验室组件来说明铜在水环境中的重要性，这些组件将向中学生传达有关海洋环境中金属营养/污染的一些基本概念。这项研究将与水生探险公司合作进行，后者提供教育项目，将缺乏服务的年轻人与科学联系起来。广泛影响这项研究将揭示海洋蓝藻适应沿海和低营养环境中金属水平的一些主要机制。因此，这些结果将有助于我们了解这些生物的分布和多样性与全球初级生产力的关系。它们应该会导致沿海环境中金属应力和污染的更强大的生物标记物。PI将在之前的外展活动基础上扩展，如他们在加利福尼亚州拉荷亚白桦水族馆展出的海洋基因组学博物馆，通过开发动手实验室组件，向中学生传达一些关于海洋环境中金属营养/污染的基本概念。这将与水上探险公司合作进行，后者提供教育项目，将服务不足的年轻人与科学联系起来，激励环境行动，并增加对海洋栖息地的接触。此外，还将培训微生物金属生理学跨学科领域的一名本科生和研究生。

Trace metal sample handling and analysis have led to the discovery that tiny (nanomolar) levels of metals such as iron are having profound influences on the diversity, abundance, and carbon fixation of primary producers in the oceans. One of these important primary producers, marine cyanobacteria, have similarly been shown to be affected, positively and negatively, by copper (natural and anthropogenic) levels and may also be influenced by cobalt and nickel levels. At the same time, cyanobacteria and other phytoplankton are changing the distributions of metals and their reactivity through uptake, which causes measurable depletion of metals in surface waters, and through the extra-cellular production of metal binding ligands. Because of the importance of copper in aquatic environments, the PIs will characterize copper metabolism in marine cyanobacteria using model Synechococcus strains from oligotrophic environments and from coastal environments that have very different metal physiologies revealed by the whole genome sequencing projects. They will characterize how the strains respond to different copper levels using whole genome microarrays that probe the global response of the cell and will combine these studies with state of the art characterization of intracellular metal levels and other measures of cellular physiology and photosynthetic capacity. Molecular genetics studies of diverse copper associated genes will be undertaken to determine their function in the cell. Preliminary results have found a potential candidate for an intracellular copper binding protein that is conserved in all marine cyanobacteria. At the same time, preliminary results have found that coastal cyanobacteria have greater resistance to copper than open ocean species and this might be due to a novel copper binding or efflux system. The PIs will illustrate the importance of copper in aquatic environments by developing hands-on lab components that will communicate some basic concepts around metal nutrition/pollution in the marine environment to middle school students. This will be undertaken in collaboration with Aquatic Adventures, who provide educational programs that connect underserved youth to science.Broader Impacts This research will reveal some of the major mechanisms by which marine cyanobacteria have adapted to metal levels in coastal and oligotrophic environments. Thus these results will help us understand the distribution and diversity of these organisms in relation to global primary productivity. They should lead to more robust biomarkers for metal stress and pollution in coastal environments. The PIs will expand on a previous outreach activity like their museum exhibit on marine genomics at the Birch Aquarium, La Jolla CA, by developing hands-on lab components that will communicate some basic concepts around metal nutrition/pollution in the marine environment to middle school students. This will be undertaken in collaboration with Aquatic Adventures, who provide educational programs that connect underserved youth to science, inspire environmental action, and increase exposure to marine habitats. In addition an undergraduate and graduate student in the interdisciplinary field of the metal physiology of microbes will be trained.