Hopanoid Physiology: Implications for Microbial Life on the Early Earth

保存在古代沉积岩中的脂质生物标志物提供了地球早期生命的关键记录。它们携带的结构和同位素信息直接反映了相关生物体的生化途径。这些信息可以揭示早期进化和环境，并提供了少数几个可用的窗口之一，以了解古代生态系统的组成。其中最古老的脂质生物标志物是Hopanes，细菌Hopanoids的成岩产物。合成hopanoids或类似分子的能力可能存在于细菌的最后共同祖先中，并且该途径随后从大多数分类群中丢失。Hopanoids是为数不多的直接记录早期地球生物活动的生物产物之一。该项目将采取生理学方法来了解hopanoids的进化和功能，目的是增加我们对早期地球条件的了解。研究者将进行三部分的研究：1）hopanoids的生物合成和细胞环境，2）表型和生理学，3）hopanoids修饰的适应性和早期生命进化的影响。该项目产生的更广泛的影响将通过指导，社区推广和本科教育来实现。PI马克思和皮尔逊将在整个项目中指导博士后研究员亚历山大布拉德利。反过来，布拉德利博士将通过哈佛的微生物科学计划指导一名本科生，该计划大力招收来自经济和种族背景不同的学生。通过微生物科学计划，我们还将参加一系列为期一天的专业发展研讨会的K-12科学教师。PI和布拉德利博士将参与开发课程和领导实验室活动，向来自不同背景的教师传达尖端成果。最后，这个项目将形成一个新的模块的基于项目的研究课程的基础上，旨在教研究技能的本科生在微生物进化的更广泛的主题。

Lipid biomarkers preserved in ancient sedimentary rocks provide a key record of early life on Earth. They carry structural and isotopic information directly reflecting the biochemical pathways of their associated organisms. This information can shed light on early evolution and environments and provides one of the few available windows to the composition of ancient ecosystems. Among the most ancestral lipid biomarkers are the hopanes, diagenetic products of bacterial hopanoids. The ability to synthesize hopanoids or similar molecules probably was present in the last common ancestor of Bacteria, and this pathway subsequently was lost from most taxonomic groups. Hopanoids are one of the few biological products that directly record biological activity on the early Earth. This project will take a physiological approach to understanding the evolution and function of hopanoids with the goal to increase our understanding of conditions on early Earth. The PIs will undertake a three-part study: 1) Biosynthesis and cellular setting of hopanoids, 2) Phenotype and physiology, 3) Adaptation to hopanoid modification and implications for evolution of early life.The broader impacts resulting from this project will be realized through mentoring, community outreach, and undergraduate education. PIs Marx and Pearson will mentor postdoctoral fellow Alexander Bradley throughout the project. In turn, Dr. Bradley will mentor an undergraduate student through Harvard's Microbial Sciences Initiative, which makes a strong effort to recruit students from economically and ethnically diverse backgrounds. Through the Microbial Sciences Initiative we will also participate in a series of day-long professional development workshops for K-12 science teachers. The PIs and Dr. Bradley will participate in developing the curriculum and leading laboratory activities to communicate cutting-edge results to teachers from diverse backgrounds. Finally, this project will form the basis for a new module of a project-based research course designed to teach research-skills to undergraduates within the broader theme of microbial evolution.