Connecting Trace Elements and Metalloenzymes Across Marine Biogeochemical Gradients

伍兹霍尔海洋研究所的两名科学家将确定酶活性在微量金属循环中的作用。 具体而言，研究人员将解决以下问题：（1）热带北太平洋下沉颗粒有机物质的降解可能受到微生物合成锌蛋白酶的能力的影响，而锌蛋白酶的合成能力又受锌的丰度或可用性控制；（2）汞的甲基化部分受含钴酶的活性控制，因此向含咕啉的酶或负责甲基化的辅助因子供应不稳定的钴。 为了实现他们的目标，他们将从热带北太平洋沿生物地球化学梯度（沿西经 150°，从 18°N 到赤道）的三个监测站收集痕量金属和金属酶的溶解和颗粒样品。 还将获得来自金属清洁沉积物捕集器的沉降颗粒。这些样品还将用于使用金属、金属螯合剂、B12 和蛋白酶的改良剂进行船上孵化实验，以检查海洋“暮光区”（100-500 m）内有机物异养、酶促降解的敏感性和金属限制。 这项研究将产生一个新的宏蛋白质组/金属酶数据集，该数据集应该提供对金属生物地球化学循环的见解，以及初级生产力的共同限制和对透光区碳输出的控制。 就更广泛的影响而言，将创建一个在线宏蛋白质组数据服务器，以便社区可以访问该研究生成的原始数据文件。 预计目前支持者参与的俄亥俄州克利夫兰公立学校外展活动将继续进行。 在这项工作中，支持者计划利用养成孵化实验来教导学生营养物质在浮游植物生长中的作用。 该项目将支持和培训一名研究生。

Two scientists from Woods Hole Oceanographic Institution will determine the role of enzymatic activity in the cycling of trace metals. Specifically the researchers would address the following questions: (1) degradation of sinking particulate organic material in the Tropical North Pacific can be influenced by the ability of microbes to synthesize zinc proteases, which in turn is controlled by the abundance or availability of zinc, and (2) methylation of mercury is controlled, in part, by the activity of cobalt-containing enzymes, and therefore the supply of labile cobalt to the corrinoid-containing enzymes or co-factors responsible for methylation. To attain their goal, they will collect dissolved and particulate samples for trace metals and metalloenzymes from three stations along a biogeochemical gradient in the Tropical North Pacific (along 150°W from 18°N to the equator). Sinking particles from metal clean sediment traps will also be obtained. The samples will also be used to carry out shipboard incubation experiments using amendments of metals, metal-chelators, B12, and proteases to examine the sensitivity and metal limitation of heterotrophic, enzymatic degradation of organic matter within the oceanic "Twilight Zone" (100-500 m). This study will result in a novel metaproteomic/metalloenzyme datasets that should provide insights into the biogeochemical cycling of metals, as well as co-limitation of primary productivity and controls on the export of carbon from the photic zone. In terms of broader impacts, an online metaproteomic data server would be created so the community can have access to the raw data files generated by this research. It is anticipated that the current public school outreach activities in Cleveland, Ohio in which the proponents are involved will be continued. During this effort, the proponents plan to use grow-out incubation experiments to teach students about the role of nutrients in phytoplankton growth. One graduate student would be supported and trained by this project.