The Outer Surface of Vibrio cholerae

项目摘要 细菌的细胞被膜是一种非凡而复杂的结构，它保护细菌免受它们的 周边环境革兰氏阴性菌的一个明显特征是存在外膜 包裹着这些生物体的肽聚糖层。而内膜则由 甘油磷脂，外膜是一个独特的，不对称的双层与甘油磷脂限制 脂质A是一种独特的糖脂，位于外叶。脂质A是以下的脂质部分： 脂多糖（LPS）并将LPS锚定到细菌表面。细菌已经进化出各种 机制，以适应他们的不可预测的，往往是敌对的环境，包括重塑战略， 它们的膜结构通常，这些修饰提供对哺乳动物细胞的组分的抗性。 天然免疫系统和调节宿主识别入侵微生物。的脂质A结构域， LPS对人类有毒，并且通过TLR 4 - 1的识别而有效刺激先天免疫系统。 MD2许多革兰氏阴性病原体改变其脂质A结构以逃避宿主检测。 此外，脂质A和甘油磷脂的结构改变可以直接影响细菌对细菌的耐药性。 先天免疫效应物，如宿主抗微生物肽。 这项提议的总体目标是揭示霍乱弧菌， 霍乱的病原体，重塑它的膜结构和这种重塑所起的作用 在毒力方面。本项目的具体目标是：（1）甘氨酸的生物化学和遗传分析 （2）磷酸乙醇胺修饰的生化和遗传分析; 诉胆固醇脂多糖;（3）阐明胆固醇弧菌中磷脂重塑所需的机制;和（4） 霍乱弧菌膜重塑对宿主先天免疫应答的影响。完成这些 目的将直接有助于我们了解脂质重塑/修饰机制如何影响 发病机制最后，从这项工作中不仅可以更好地了解霍乱， 疫苗开发的途径和产生工程化LPS结构的能力， 潜在的佐剂和/或LPS拮抗剂。

PROJECT ABSTRACT The bacterial cell envelope is a remarkable and complex structure that guards bacteria from their surrounding environment. A defining feature of Gram-negative bacteria is the presence of an outer membrane that encapsulates the peptidoglycan layer of these organisms. While the inner membrane is composed of glycerophospholipids, the outer membrane is a unique, asymmetric bilayer with glycerophospholipids confined to the inner leaflet and lipid A, a unique saccharolipid, localized to the outer leaflet. Lipid A is the lipid moiety of lipopolysaccharide (LPS) and anchors LPS to the bacterial surface. Bacteria have evolved various mechanisms to adapt to their unpredictable and often hostile surroundings, including strategies for remodeling their membrane architecture. Often these modifications provide resistance to components of the mammalian innate immune system and modulate host recognition of the invading microorganism. The lipid A domain of LPS is toxic to humans and potent stimulator of the innate immune system through via recognition by TLR4- MD2. A number of Gram-negative pathogens modify their lipid A structure to evade host detection. Additionally, structural alteration of lipid A and glycerophospholipids can directly impact bacterial resistance to innate immune effectors such as host antimicrobial peptides. The overall objective of this proposal is to unravel the molecular mechanisms by which Vibrio cholerae, the causative agent of the disease cholera, remodels it membrane architecture and the role this remodeling plays in virulence. The Specific Aims of the current proposal are: (1) biochemical and genetic analysis of glycine modification of V. cholerae LPS; (2) Biochemical and genetic analysis of phosphoethanolamine modification of V. cholerae LPS; (3) elucidation of machinery required for phospholipid remodeling in V. cholerae; and (4) impact of V. cholerae membrane remodeling on the host innate immune response. The completion of these Aims will directly contribute to our understanding of how lipid remodeling/modification machinery impacts pathogenesis. Finally, from this work will come not only a better understanding of the disease cholera, but new avenues for vaccine development and the ability to generate engineered LPS structures that could serve as potential adjuvants and/or LPS antagonists.