Metabolic Currencies of the Ocean Carbon Cycle

微生物在海洋中碳和营养物质循环中的作用？地球上最大的生物系统？最初是在40年前被描述的。现在，我们知道地球上一半的初级生产是由海洋浮游植物完成的，其中一半在几周内被海洋细菌循环利用。这项提议是微生物学家和化学家之间的合作，以确定在海洋表层浮游植物和细菌之间传递的特定化合物。确定海洋微生物食物网的关键化学物质将提供对海洋碳循环如何被调节的见解，生成数据以改进海洋碳模型，并在微生物学和化学的界面上培训新的科学家。在微生物生态学的实践学习机会将提供给高中学生，无论是在课堂上还是在乔治亚海岸的海洋生态系统。在海洋表面碳循环中，维持微生物自养生物和异养生物之间碳流动的浮游植物代谢物将在本项目中确定。由细菌-浮游植物共培养组成的模型系统矩阵将用于基于细菌转运基因表达模式的关键代谢物的生物测定。候选代谢物的化学特性及其潜在生态作用的评估将通过与细菌转运体突变体共培养的外代谢组学分析来进行。先进的质谱法和核磁共振将用于代谢组学分析，利用两者的灵敏度和化合物鉴定优势。候选代谢物在海洋微生物组和其他微生物系统中的分布将通过挖掘环境序列数据集来表征同源转运体基因。该项目代表了一种鉴定微生物组功能中重要代谢物的新方法，这些化合物通常难以用标准化学方法处理，因为它们的浓度低，生物需求高。

The roles of microbes in cycling carbon and nutrients in the ocean ? the largest biological system on Earth ? were initially described about 40 years ago. Now, it is known that half of Earth's primary production is carried out by marine phytoplankton, and half of that is recycled within weeks by marine bacteria. This proposal is a collaboration between microbiologists and chemists to identify the specific compounds that pass between phytoplankton and bacteria in surface ocean waters. Identifying the key chemicals of the ocean's microbial food web will provide insights into how the marine carbon cycle is regulated, generate data to improve ocean carbon models, and train new scientists at the interface of microbiology and chemistry. Hands-on learning opportunities in microbial ecology will be provided for high school students, both in the classroom and in marine ecosystems of the Georgia coast. Phytoplankton metabolites that sustain the flow of carbon between microbial autotrophs and heterotrophs in the surface ocean carbon cycle will be identified in this project. A matrix of model systems consisting of bacteria-phytoplankton co-cultures will be used as biological assays for key metabolites based on expression patterns of bacterial transporter genes. The chemical identity of candidate metabolites and evaluation of their potential ecological role will be carried out by exometabolomic analysis of co-cultures with bacterial transporter mutants. Both advanced mass spectrometry and NMR will be used for metabolomics analysis, taking advantage of the sensitivity and compound identification strengths of each. The distribution of candidate metabolites in the ocean microbiome and other microbial systems will be characterized by mining environmental sequence datasets for orthologous transporter genes. This project represents a novel approach to identifying metabolites important in microbiome function, compounds often difficult to address with standard chemical approaches because of their low concentrations and high biological demand.