Molecular Probes for Nutrient Stress in Phytoplankton: Emiliania Huxleyi as a Model

Palenik 9818543浮游植物营养胁迫的分子探针：Emily huxleyi作为模型。浮游植物的类型和生理状态都影响海洋中的主要过程，如固碳、钙化、硫磺气体排放和有毒水华的形成。然而，我们了解单个浮游植物物种或单个细胞领域的生理状态的能力是有限的。大多数生物现场测量(例如，碳固定、C：N比、Fv/Fm)目前都在整个浮游植物群落中进行整合。从长远来看，对个别“基石”浮游植物物种的生理生态的了解将为生态系统过程提供更机械、更具预测性的理解。艾美莲是一种丰富的、世界性的浮游植物物种，由于其在方解石(球石)和硫磺气体DMS的水柱中产生，在全球碳和硫的生物地球化学循环中具有重要作用。它既存在于营养稀少的环境中，也存在于浅海环境中，在一些已知的地点，它会形成卫星图像中可见的大规模水华。到目前为止，我们对这种生物的生态学的了解主要集中在这些水华现象上。浮游植物生态学领域的研究目标之一是开发浮游植物营养状况的不依赖孵化的探针。根据以前的工作，已经开发出一种针对细胞表面蛋白Nrp1的抗体，这种蛋白存在于氮胁迫下，但不存在于硝酸盐或氨氮充足的E.Huxley中。在这项研究中，该抗体将被用来开发一种现场方法来表征自然的虎纹伊蚊种群的生理状态。整个细胞测试将得到优化，其效率和灵敏度将被表征，以检测低营养环境中存在的细胞数量。荧光显微镜和图像分析将被用来量化表达Nrp1的细胞的数量，理想情况下是表达的相对水平。针对完整的完整细胞的抗体将被开发来计算样本中氮应激细胞的总数和百分比。之前从加州海流和挪威海岸获得的一些样本将首先进行实地测试，以确定是否存在氮胁迫的细胞。对特定浮游植物群体的生理状态的演示将是新颖的。这项工作将涉及对一名研究生和一名或多名本科生进行培训，使他们掌握将免疫学探针应用于海洋生态问题的新技术。

Palenik 9818543Molecular Probes for Nutrient Stress in Phytoplankton: Emiliania huxleyi as a model.Numerous examples exist where both the type and physiological status of the phytoplankton influence major processes in the oceans such as carbon fixation, calcification, sulfur gas emission, and toxic bloom formation. Our ability to understand the physiological status in the field of individual phytoplankton species or individual cells is limited, however. Most biological field measurements (carbon fixation, C:N ratio, Fv/Fm, for example) currently integrate over the whole phytoplankton community. In the long term, an understanding of the physiological ecology of individual "keystone" phytoplankton species will provide a more mechanistic, predictive understanding of ecosystem processes.Emiliania huxleyi is an abundant, cosmopolitan phytoplankton species which is important in the global biogeochemical cycles of carbon and sulfur because of its production in the water column of calcite (coccoliths) and the sulfur gas DMS. It is present in both oligotrophic and neritic environments and in some locations is known to form massive blooms visible in satellite images. To date our understanding of the ecology of this organism has focused on these bloom phenomena.One of the research goals of the field of phytoplankton ecology is the development of incubation-independent probes of phytoplankton nutrient status. From previous work an antibody to a cell surface protein, NRP1, that is present in nitrogen-stressed, but not nitrate--replete or ammonia-replete E. huxley has been developed. In this study the antibody will be used to develop a field method for characterizing the physiological state of natural E. huxleyi populations. A whole cell assay will be optimized and its efficiency and sensitivity characterized for examining cell numbers down to those present in oligotrophic environments. Fluorescence microscopy and image analysis will be used to quantify the number of cells expressing NRP1 and ideally the relative level of expression.An antibody to intact whole cells will be developed to count the total and percent nitrogen-stressed cells in samples. A few previously obtained samples from the California current and the coast of Norway will be tested initially for the presence of nitrogen-stressed cells in the field. The demonstration of the physiological state of a specific phytoplankton group would be novel. This work will involve the training of one graduate student and one or more undergraduates in emerging techniques for applying immunological probes to marine ecological questions.