Development of novel mass spectrometric visualization approaches for the metabolic interaction of microbial communities in marine environments

海洋微生物形成复杂的群落，具有极端的分类和遗传多样性。这些群落在全球生物地球化学过程中起着重要作用。除了对全球生态系统的基本学术认识外，海洋微生物群落的研究对人类具有重要意义。随着下一代DNA群落测序（宏基因组学）的发展，微生物及其环境中的化学相互作用分析对于理解这些复杂的生态系统非常重要。随着质谱（MS）技术的不断提高，代谢物的非靶向分析（代谢组学）被引入到许多研究领域。与典型的MS-based精确测定海水样品中溶解有机物的质量相比，新的代谢组学工作流程通常采用非靶向串联质谱法。该技术固有的优点包括通过气相分离后的化合物特定峰模式具有更高的选择性。因此，已知分子可以更容易地识别，另一方面，未知分子的结构（从头开始）表征将大大提高。本提案的初始任务将是建立一个非靶向代谢组学工作流，用于表征海水中溶解有机物。除了生成详细的代谢清单外，不同地理和时间点代谢物浓度的空间和时间分辨率成像是本提案的主要目标。由此生成的代谢浓度图将通过多变量统计方法与相同样本量的微生物清单进行比较。本研究的最终目的是显示微生物模式内的代谢相互作用和关系。该工作流程的可行性将首先在概念验证研究中得到验证，该研究包括在圣地亚哥海岸附近进行小型采样活动，并将扩展到更大的采样区域，在那里将研究其他生物相关事件，如藻华。本研究结果将大大提高我们目前对海洋微生物相互作用的认识，并进一步产生新的生物学假设。元基因组学和元代谢组学的结合将为微生物生态系统的研究建立一个重要的新工具箱，是迈向（海洋）生态系统生物学不可缺少的一步。

Marine microorganisms form complex communities with extreme taxonomic and genetic diversity. These communities play an important role in global biogeochemical processes. Besides the basic academic understanding of such global ecosystems, the research on marine microbial communities is of great importance for mankind. Along with next-generation DNA community sequencing (metagenomics), analysis of chemical interaction within microorganisms and their environment is important for the understanding of these complex ecosystems.With the continuous technical enhancement of mass spectrometry (MS), non-targeted analysis of metabolites (metabolomics) was introduced in many fields of research. In contrast to the typically MS-based exact mass determination for dissolved organic matter in marine water samples analysis, novel metabolomics workflows often apply non-targeted tandem mass spectrometry. The inherent advantage of this technique includes the higher selectivity through compound specific peak patterns after gas phase dissociation. Known molecules can thus be easier identified and the structural (de novo) characterization of unknowns on the other hand will be dramatically improved.The initial task of this proposal will be the establishment of a non-targeted metabolomic workflow for the characterization of dissolved organic matter in seawater. In addition to the generation of detailed metabolic inventories, the spatial and time-resolved imaging of metabolite concentration at different geographic and time points is the primary goal of this proposal. The herby generated metabolic concentration maps will then be compared to microbial inventories of the same sample sizes through multivariate statistical approaches. The final aim of this study is to shown metabolic interactions and relations within microbial patterns.The feasibility of this workflow will be first validated in a proof-of-concept study that includes a small sampling campaign close to the coast of San Diego and will be expanded to a bigger sampling area where other biological relevant events, like an algal bloom, will be studied. The results of this study will significantly improve our current knowledge of marine microbial interaction and furthermore generate novel biological hypothesis. The combination of metagenomics and meta-metabolomics will moreover establish an important new toolbox for the investigation of microbial ecosystems and is an indispensable step towards (marine) ecosystem-biology.