CAREER: Biosynthesis of lipid monolayer membranes in Bacteria

细胞膜界定了生命和环境之间的物理界限。这个项目将大大增加我们对单层细胞膜的理解，这是膜结构的变化，可能有助于微生物在压力环境中生存。揭示单层膜的生物学作用，以及产生单层膜所需的生物化学，将揭示微生物在不同环境和某些恶劣环境中生存的一些机制。提高对单层膜的理解也将为生物技术的工程微生物开辟新的途径。当地高中生和大学生将参与研究。研究人员、参与的学生和高中教师之间的合作将形成一个以环境微生物学为重点的高中教学模块。这个项目的另一个成果将是建立一个互动式区域土壤数据库。该项目将定义环境约束和生物化学机制，控制生产跨膜脂质和单层细胞膜在酸杆菌。脂质单层和跨膜脂质的功能作用仍然难以捉摸。跨膜脂质被认为可以提高对高温和低pH值的耐受性，因为它们通常与嗜极性生活方式有关。然而，它们存在于许多中温原核生物中，如土壤细菌物种，使这一结论变得混乱。该项目将直接探索单层膜之间的联系，细菌细胞生理学，和生物合成膜跨越脂类（支链二烷基甘油四酯和四醚脂类）使用易处理的酸杆菌模型系统。一个目标是为跨膜脂质生产生成表型图谱的环境。另一个目标将是识别和表征涉及跨膜脂质生物合成的生化过程。这两个目标都将利用脂质组学、转录组学和比较基因组学方法来确定生产支链二烷基甘油四酯和四醚脂的关键调控和酶途径。一个额外的组成部分将引入跨膜脂质生物合成能力，以其他细菌物种。总的来说，这些目标将加深我们对原核生物中脂质结构、膜功能和细胞生理学之间关系的理解。该奖项反映了美国国家科学基金会的法定使命，并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，被认为值得支持。

Cell membranes define the physical boundary between life and the environment. This project will substantially increase our understanding of monolayer cell membranes, which are variations in membrane structure that may help microbes survive in stressful environments. Uncovering the biological role of monolayer membranes, and the biochemistry required to produce them, will reveal some of the mechanisms microbes use to inhabit diverse and in some cases harsh environments. Improved understanding of monolayer membranes will also open new avenues in engineering microbes for biotechnology. Local high school students and undergraduates will participate in the research. Collaborations between researchers, participating students, and high school teachers will result in a high school teaching module focused on environmental microbiology. An additional outcome of this project will be the creation of an interactive regional soil database.This project will define the environmental constraints and biochemical mechanisms that govern production of membrane-spanning lipids and monolayer cell membranes in the Acidobacteria. Functional roles for lipid monolayers and membrane-spanning lipids remain elusive. Membrane-spanning lipids are hypothesized to provide increased tolerance to elevated temperatures and low pH, as they are often associated with extremophilic lifestyles. However, their presence in numerous mesophilic prokaryotes, such as soil-dwelling bacterial species, has muddled this conclusion. This project will directly explore the connections between monolayer membranes, bacterial cell physiology, and biosynthesis of membrane-spanning lipids (branched dialkylglycerol tetraester and tetraether lipids) using tractable Acidobacteria model systems. One objective is to generate an environment to phenotype map for membrane-spanning lipid production. Another objective will be to identify and characterize biochemical processes involved in membrane-spanning lipid biosynthesis. Both objectives will utilize lipidomic, transcriptomic, and comparative genomic approaches to identify key regulatory and enzymatic pathways involved in producing branched dialkylglycerol tetraester and tetraether lipids. An additional component will be introducing membrane-spanning lipid biosynthetic capabilities to other bacterial species. Collectively, these objectives will deepen our understanding of the relationship between lipid structure, membrane function, and cell physiology in prokaryotes.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.