Environmental Phylogeny, Physiology, and Evolutionary Significance of Polycyclic Triterpenoids

多环三萜类化合物的环境系统发育、生理学和进化意义

• 批准号: 0641899
• 负责人: Ann Pearson
• 金额: $ 27.96万
• 依托单位: Harvard University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-07-01 至 2010-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0641899&HistoricalAwards=false
• 关键词: Environmental; Phylogeny; Physiology; Evolutionary; Significance

The record of lipid biomarkers preserved in ancient sedimentary rocks is a fundamental geochemical tool used to decipher early environments on Earth. In this project we seek to achieve a better understanding of the (i) genetic diversity, (ii) evolutionary history and (iii) the physiological benefit that drove the evolution of a particular class of these biomarkers, the polycyclic triterpenoids. These compounds include the steroids (e.g., cholesterol) and the analogous microbial compounds known as hopanoids. This project will have three primary components. We will examine contrasts between aerobic and anaerobic environments and between terrestrial and aquatic system, by sequencing genes for hopanoid biosynthesis. We hope to determine the primary organisms and settings that are sources for these important geological biomarkers. We will study whether these compounds confer a phenotype that is related to the presence of oxygen, by using genetically tractable strains of common laboratory microorganisms. Finally, we will use large-insert clone libraries to look for sequences for other varieties of triterpenoid cyclases. This may help us understand the evolutionary history of this gene family. This project represents the first systematic study to utilize molecular biological approaches to survey a major lipid biosynthetic pathway of interest to geobiology. We hope to provide new and robust information about the evolution of aerobic organisms, oxygenation of Earth surface environments, and the geologic record of lipid biomarkers.

在古代沉积岩中保存的脂质生物标志物的记录是一种基本的地球化学工具，用于破译地球上的早期环境。 在这个项目中，我们试图更好地了解（i）遗传多样性，（ii）进化史以及（iii）推动这些特定类别的生物标志物（多环芳三萜类化合物）演变的生理益处。 这些化合物包括类固醇（例如胆固醇）和类似的微生物化合物，称为霍托甘油棒。 该项目将具有三个主要组件。 我们将通过测序基因进行霍托烷生物合成，研究有氧和厌氧环境以及陆地和水生系统之间的对比度。 我们希望确定这些重要地质生物标志物来源的主要生物和环境。 我们将研究这些化合物是否通过使用常见实验室微生物的遗传障碍菌株来赋予与氧存在相关的表型。 最后，我们将使用大型插入克隆文库来寻找其他三萜循环酶的序列。 这可能有助于我们了解这个基因家族的进化史。 该项目代表了使用分子生物学方法来调查地球生物学感兴趣的主要脂质生物合成途径的首个系统研究。 我们希望提供有关有氧生物的演变，地面环境的氧合以及脂质生物标志物的地质记录的新信息。