Collaborative Research: The Role of Copper in the High Affinity Iron Uptake systems of Eukaryotic Marine Phytoplankton

合作研究：铜在真核海洋浮游植物高亲和力铁吸收系统中的作用

• 批准号: 0526704
• 负责人: Mark Wells
• 金额: $ 38.42万
• 依托单位: University of California-Santa Cruz
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-08-15 至 2009-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0526704&HistoricalAwards=false
• 关键词: Collaborative; Research; Role; Copper; Affinity

Iron enrichment of High Nitrate, Low Chlorophyll (HNLC) waters of the subarctic Pacific lead seed populations of Pseudo-nitzschia (pennate) diatoms to rapidly bloom. Recent findings from laboratory and field experiments show that Pseudo-nitzschia species posses the ability to grow on strongly complexed Fe (III), and that this ability is directly dependent on Cu availability. This Fe uptake system is induced under Fe-stress, and its efficiency contrasts what is known about other coastal diatoms. Genes homologous to high affinity Fe uptake proteins are found in T. pseudonana, and should be present in Pseudo-nitzschia species. Because T. pseudonana possesses putative genes for high-affinity Fe uptake proteins and can still be readily starved for Fe under normal laboratory culture conditions, it is implied that the Fe uptake system in T. pseudonana is incomplete, or that some environmental factor prevents induction or limits the functionality of the high affinity Fe uptake system in contrast to the highly efficient system in Pseudo-nitzschia. As a result, more molecular and physiological studies are needed to better ascertain the mechanism and functionality of the high affinity Fe uptake systems in eukaryotic diatoms such as T. pseudonana and Pseudo-nitzschia species. In this study, researchers at the University of California at Santa-Cruz and the University of Rhode Island will focus on understanding the relationship between Fe redox chemistry in seawater and the molecular, biologically mediated reactions that render Fe availability for uptake by eukaryotic phytoplankton. The team of scientists will establish whether or not the structural components of the high affinity Fe uptake system indicated by sequence homology can function in T. pseudonana and if the same components are present and can function in Pseudo-nitzschia spp. The researchers will also examine how the gene expression patterns of the high affinity iron uptake homologues are induced by Fe stress, and how the presence of these proteins correlates with the rates of Fe and Cu uptake in Pseudo-nitzschia spp. and T. pseudonana. In addition, the work will determine which cell fraction harbors this additional Cu quota and whether or not the increased Cu requirement of Pseudo-nitzschia under Fe stress occurs with other phytoplankton species in offshore waters. This work will be important to understanding the mechanistic controls that effect the Fe uptake of large diatoms, as well as provide insight into how the natural or anthropogenic fluxes of iron to HNLC waters influence the export of carbon to the deep ocean and effect the global climate. In terms of broader impacts, the project will provide the training, education, and research to a beginning female investigator, a Ph.D. student, and a graduate student. A high school teacher who will bring the field results to the science classroom will also participate in the project.

亚北极太平洋高硝酸盐低叶绿素（HNLC）沃茨的铁富集导致伪菱形藻（羽状）硅藻种子种群迅速开花。最近的研究结果表明，从实验室和现场实验表明，拟菱形藻物种的生长能力强络合铁（III），这种能力是直接依赖于铜的可用性。 这铁吸收系统诱导铁应力下，其效率对比是已知的其他沿海硅藻。 在T.拟菱形藻属的物种中应该存在。因为T.在正常培养条件下，黑胸藻具有高亲合铁吸收蛋白基因，且仍能耐受铁的饥饿，这表明黑胸藻的铁吸收系统可能与铁的吸收有关。 这可能是由于假菱形藻的铁吸收系统不完整，或者是由于某些环境因素阻止了铁吸收系统的诱导，或者限制了铁吸收系统的功能，而假菱形藻的铁吸收系统是高效的。 因此，需要更多的分子和生理学研究来更好地确定真核硅藻（如T. Nitzschia和Pseudo-nitzschia种。 在这项研究中，加州大学圣克鲁斯分校和罗得岛大学的研究人员将专注于了解海水中Fe氧化还原化学与分子生物介导的反应之间的关系，这些反应使Fe可用于真核浮游植物的吸收。 科学家小组将确定由序列同源性指示的高亲和力铁吸收系统的结构组分是否可以在T。如果相同的成分存在并能在假菱形藻中起作用， 研究人员还将研究高亲和力铁吸收同系物的基因表达模式是如何被铁胁迫诱导的，以及这些蛋白质的存在如何与伪菱形藻的铁和铜吸收率相关。和T.是的 此外，这项工作将确定哪些细胞部分窝藏这一额外的铜配额，以及是否增加铜的需求，假菱形藻铁胁迫下发生与其他浮游植物物种在近海沃茨。这项工作将是重要的理解机制的控制，影响铁的吸收大型硅藻，以及提供洞察如何自然或人为通量的铁HNLC沃茨影响碳出口到深海和影响全球气候。 就更广泛的影响而言，该项目将为一名初出茅庐的女研究员提供培训、教育和研究，一个学生，一个研究生。一位将现场结果带到科学课堂的高中教师也将参与该项目。