Determining the function of sterol lipids in the bacterial domain

确定甾醇脂质在细菌域中的功能

• 批准号: 1919153
• 负责人: Paula Welander
• 金额: $ 82.18万
• 依托单位: Stanford University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-08-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1919153&HistoricalAwards=false
• 关键词: Determining; function; sterol; lipids; bacterial

The overall goal of this project is to determine the functions cholesterol-like lipid molecules have in bacteria. Cholesterol plays many essential roles in the biology of higher organisms, but the importance of cholesterol-like lipids in simpler organisms like bacteria is not well understood. The hypothesis to be tested here is that sterols allow bacteria to sense and react to low levels of oxygen that adversely affect their ability to grow. The work has the potential to expand our understanding of a fundamental cellular pathway and can inform future studies that have broad societal impacts - from human physiology to response to environmental change. This project will also contribute to the goal of broadening participation in STEM fields by providing scientific training for postdoctoral scholars as well as graduate and undergraduate students from diverse backgrounds. Undergraduate underrepresented minority students will participate in this project through two summer programs at Stanford to undertake research projects that are directly relevant to the scientific goals of this proposal. Further, a seminar series that will bring early career underrepresented scientists to Stanford to present their research and interact with students and postdoctoral scholars will be developed and executed by the principle investigators, both of whom are underrepresented minority women scientists themselves.In this project, a variety of molecular studies will be undertaken to investigate the functional role of cholesterol-like lipids, or sterols, in the bacterium Methylococcus capsulatus. M. capsulatus, an environmentally relevant microbe that grows by consuming methane and oxygen, was the first bacterium shown to produce sterols over 40 years ago. However, the function of these very important lipids in bacteria remains a mystery. This project will test the hypothesis that the biosynthesis of certain sterol structures within this microbe signals to the cell that it is experiencing low oxygen stress (termed hypoxia), a condition that adversely affects the bacterium's physiology. To test this hypothesis, the researchers will: (1) determine how varying oxygen levels affect sterol synthesis in M. capsulatus; (2) identify and characterize proteins necessary for transporting specific sterol structures to the outer bacterial membrane under different oxygen conditions; and 3) determine what genes are turned on and off when M. capsulatus sterol-deficient mutant cells are grown under oxygen-replete and oxygen-limited conditions. Together, these studies have the potential to identify unique sterol-binding proteins and transporters, as well as novel sterol regulatory mechanisms in bacteria. This type of a regulatory role for sterols has been shown in eukaryotes but would represent a novel function in the bacterial domain.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

该项目的总体目标是确定胆固醇样脂质分子在细菌中的功能。胆固醇在高等生物体的生物学中起着许多重要作用，但胆固醇样脂质在细菌等简单生物体中的重要性还没有得到很好的理解。这里要测试的假设是，甾醇允许细菌感知并对低水平的氧气做出反应，这对它们的生长能力产生了不利影响。这项工作有可能扩大我们对基本细胞通路的理解，并为未来具有广泛社会影响的研究提供信息-从人类生理学到对环境变化的反应。该项目还将通过为博士后学者以及来自不同背景的研究生和本科生提供科学培训，促进扩大STEM领域参与的目标。代表性不足的本科少数民族学生将通过斯坦福大学的两个暑期项目参与该项目，承担与本提案的科学目标直接相关的研究项目。此外，一系列研讨会将把早期职业生涯中代表性不足的科学家带到斯坦福大学，介绍他们的研究，并与学生和博士后学者互动，将由主要研究人员开发和执行，他们都是代表性不足的少数民族女科学家。在荚膜甲基球菌中。M. capsulatus是一种通过消耗甲烷和氧气而生长的环境相关微生物，是40多年前第一种被证明能产生甾醇的细菌。然而，这些非常重要的脂质在细菌中的功能仍然是一个谜。该项目将测试这样一种假设，即这种微生物中某些甾醇结构的生物合成向细胞发出信号，表明它正在经历低氧应激（称为缺氧），这种条件对细菌的生理产生不利影响。为了验证这一假设，研究人员将：（1）确定不同的氧气水平如何影响M。囊状;（2）鉴定和表征在不同氧条件下将特定甾醇结构转运到细菌外膜所必需的蛋白质;和（3）确定当M. capsulatus甾醇缺陷突变细胞在充氧和限氧条件下生长。总之，这些研究有可能确定独特的甾醇结合蛋白和转运蛋白，以及细菌中新的甾醇调节机制。甾醇的这种调节作用已在真核生物中得到证实，但在细菌领域将代表一种新的功能。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的知识价值和更广泛的影响审查标准进行评估来支持。