SGER: The Role of Metal Reduction in the Relationship Between Marine Phytoplankton and Their Associated Bacteria

9614005夏皮罗在浮游植物与其相关细菌之间的关系中，假定细菌从浮游植物的分泌物中获得营养，浮游植物利用细菌作为特定维生素的来源、N或P的来源，或作为替代碳源。该SGER项目假设该协会的主要作用与金属减少和收购有关。因此，藻圈将被视为细菌还原活性金属和浮游植物吸收活性金属的共生区。作为检验这一假说的第一步，研究人员将确定是否存在与浮游植物密切相关的可复制的细菌组合，以及这些组合是否能够还原金属。在这项SGER项目中，将建立俄勒冈州海岸的浮游植物克隆，随后将对常见的海洋细菌属进行16S rRNA探针分析，包括一种常见的金属还原物种腐烂希万氏菌。使用DNA扩增对与浮游植物自然样本相关的细菌进行种群分析，将使研究人员能够确定与浮游植物相关的细菌的特征，无论它们是否适合培养技术。自然样品将用从扩增的DNA中产生的16S rRNA探针进行探测。这项研究的意义在于，它有可能为浮游植物吸收金属提供一种基于共生的机制。这可能被证明是理解世界海洋中强烈建议限制初级生产的金属区域的关键。***

9614005 SHAPIRO In the relationship between phytoplankton and their associated bacteria, it is assumed that the bacteria derive nutrition from phytoplankton exudates, and that phytoplankton utilize the bacteria as a source of specific vitamins, a source of N or P, or as an alternate carbon source. This SGER project hypothesizes that a major role of this association relates to metal reduction and acquisition. Thus, the phycosphere will be examined as a symbiotic zone of active metal reduction by bacteria and uptake by phytoplankton. As a first step in examining this hypothesis, the researchers will determine whether there are replicable assemblages of bacteria living in close association with phytoplankters, and whether these associations are capable of metal reduction. During this SGER project phytoplankton clones from the Oregon coast will be established and will subsequently be tested with 16s rRNA probe analysis for common marine bacterial genera, including Shewanella putrefaciens, a common metal-reducing species. Population analysis of bacteria associated with phytoplankton natural samples, using DNA amplification, will permit the researchers to characterize bacteria associated with phytoplankton whether or not they are amenable to culturing techniques. Natural samples will be probed with 16s rRNA probes generated from the amplified DNA. The significance of this research lies in its potential to provide a mechanism, based on symbiosis, for metal uptake by phytoplankton. This may prove critical in understanding those regions of the world's oceans where metal limitation of primary production is strongly suggested. ***