The effects of chemical structure on hydrolysis/uptake of small peptides in the marine environment

了解海洋表面碳和氮的循环是必要的，原因有很多，包括了解海洋和其他环境变化对气候变化的影响。大部分的研究焦点都集中在碳和氮的无机形式上，特别是对海洋表面溶解有机氮（DON）化合物的循环及其影响知之甚少。德克萨斯大学奥斯汀分校的研究人员将研究海洋生物群释放的多肽和蛋白质一类有机氮化合物。如果这些化合物的分子量足够小，它们就可以被细菌吸收和结合，并且/或者被细菌回收为无机氮，可能支持初级生产。转化，主要是通过细胞外酶水解，产生可被微生物吸收的小肽或游离氨基酸。本研究将探讨多肽水解的机制、多肽在海水中DON的整体分解和/或保存中的重要性，以及化学结构在影响反应途径中的作用。这项研究将使用新颖和创新的技术，这是目前使用的方法的重大进步，以检查这些过程。这些方法包括使用同位素标记的化合物以及在实验室制造的特定化合物（肽和相关化合物）。该研究将为我们对海洋氮循环中DON动力学的理解提供重要的进展。该项目将涉及研究生、本科生和高中阶段的学生，并将有一个重要的外联组成部分。互动将包括暑期本科课程、公开研讨会和相关活动，以及联合广播节目《科学与海洋》。

An understanding of the cycling of carbon and nitrogen in the surface ocean is necessary for many reasons, including understanding the impacts of marine and other environmental changes in a changing climate. Much of the research focus has been on inorganic forms of carbon and nitrogen and, in particular, little is known about the cycling of dissolved organic nitrogen (DON) compounds in the surface ocean and their impact. Researchers at the University of Texas at Austin will investigate peptides and proteins, one class or organic nitrogen compounds released from marine biota. These compounds can be taken up and incorporated if they have sufficiently small molecular weight and/or recycled back to inorganic nitrogen by bacteria, potentially supporting primary production. Conversion, primarily by extracellular enzymatic hydrolysis, produces small peptides or free amino acids that can be assimilated by microbes. The proposed research will investigate the mechanisms of peptide hydrolysis, their importance in the overall breakdown and/or preservation of DON in ocean waters, and the role of chemical structure in influencing the reaction pathways. The study will use novel and innovative techniques which are a substantial advancement over currently used approaches, to examine these processes. These approaches include the use of isotopically labeled compounds as well as specific compounds (peptides and related compounds) manufactured in the laboratory. The study should provide significant advancements in our understanding of DON dynamics in the marine nitrogen cycle. The project will involve students at the graduate, undergraduate and high school level and will have a significant outreach component. Interactions will include summer undergraduate programs, public seminars and related activities and Science and the Sea, a syndicated radio program.