Spirochete coordination of adhesion and motility in the presence of fluid shear forces

存在流体剪切力时螺旋体粘附和运动的协调

• 批准号: RGPIN-2017-06403
• 负责人: Moriarty, Tara
• 金额: $ 2.04万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=712224
• 关键词: Spirochete; coordination; adhesion; motility; presence

BACKGROUND: Spirochetes are invasive, fast-moving gram-negative-like bacteria with a helical or planar wave-form shape, internal periplasmic flagella that wrap around the cell body and drive movement by undulating wave- or corkscrew-like rotation of the cell body, and a fluid outer membrane containing few transmembrane proteins. Most spirochete adhesion proteins (adhesins) are anchored to the outer membrane by lipid anchors and are likely highly mobile. Spirochetes move faster in dense biological materials than in pure liquid, possible due to traction-conferring adhesive interactions between cells and their extracellular environment, a property that may be crucial for colonization of environments inaccessible to other bacteria. If motility depends on adhesion, then adhesins may also be mobile, especially under conditions such as adhesion to surfaces under flow in which bacterial motility and flow propel the cell body forward as the adhesion complex anchoring bacteria to surfaces remains in a fixed position. The properties and mechanisms underlying dynamic coordination of spirochete adhesion and motility in the presence and absence of flow are not yet defined, and have not been defined for most bacteria. This is largely due to the need to develop rapid, high resolution live cell imaging tools to study coordination of adhesion and motility. My laboratory is expert in developing imaging-based approaches for studying bacterial adhesion, motility and movement in flow and non-flow environments, and recently established the first imaging-based particle-tracking and biophysical analysis tools to studying bacterial adhesion and movement to surfaces under flow. We work primarily with the Lyme disease spirochete Borrelia burgdorferi (Bb), have identified multiple adhesins and extracellular matrix components targeted by these bacteria during movement, and found, unexpectedly, that Bb motility stimulates and stabilizes Bb interactions with endothelial cells under flow. OVERALL OBJECTIVE OF RESEARCH PROGRAM: To investigate the fundamental properties and mechanisms underlying coordination of adhesion and motility in Bb. Short-term objective: Develop rapid, high speed live cell imaging-based methods to study bacterial coordination of adhesion and motility. Long-term objective: Apply these methods to investigate how bacterial motility promotes adhesion to surfaces under flow, and how adhesion and motility are coordinated. SIGNIFICANCE: These studies will provide the first dynamic insight into mechanisms coordinating motility and adhesion in spirochetes. This research will be of fundamental, non-health-related interest for Canadian microbiologists, especially because it will establish methods useful for studying coordination of adhesion and motility in other bacteria, including those that form industrially- and medically-important flow-resistant biofilms.

背景：螺旋体是一种侵入性、快速移动的革兰氏阴性菌，具有螺旋或平面波形形状，内部周质鞭毛包裹在细胞体周围，并通过细胞体的波状或螺旋状旋转来驱动运动，以及含有少量跨膜蛋白的液体外膜。大多数螺旋体粘附蛋白（粘附素）通过脂质锚固定在外膜上，并且可能具有高度的移动性。螺旋体在致密的生物材料中比在纯液体中移动得更快，这可能是由于细胞与其细胞外环境之间具有牵引力的粘附相互作用，这种特性对于其他细菌无法进入的环境中的定殖可能至关重要。如果运动取决于粘附，则粘附素也可能是移动的，特别是在诸如在流动下粘附到表面的条件下，其中细菌运动和流动推动细胞体前进，因为将细菌锚定在表面的粘附复合物保持在固定位置。在存在和不存在流动的情况下，螺旋体粘附和运动的动态协调的特性和机制尚未确定，并且对于大多数细菌来说也尚未确定。这主要是因为需要开发快速、高分辨率的活细胞成像工具来研究粘附和运动的协调。我的实验室擅长开发基于成像的方法来研究流动和非流动环境中的细菌粘附、运动和运动，最近建立了第一个基于成像的颗粒跟踪和生物物理分析工具来研究细菌在流动和非流动环境中的粘附和运动。流动。我们主要研究莱姆病螺旋体伯氏疏螺旋体 (Bb)，已鉴定出这些细菌在运动过程中靶向的多种粘附素和细胞外基质成分，并意外地发现 Bb 运动刺激并稳定了 Bb 与流动下内皮细胞的相互作用。 研究计划的总体目标：研究 Bb 中粘附和运动协调的基本特性和机制。短期目标：开发基于快速、高速活细胞成像的方法来研究细菌粘附和运动的协调。长期目标：应用这些方法来研究细菌运动如何促进流动下表面的粘附，以及粘附和运动如何协调。 意义：这些研究将为螺旋体中协调运动和粘附的机制提供第一个动态见解。这项研究将引起加拿大微生物学家的基本的、非健康相关的兴趣，特别是因为它将建立可用于研究其他细菌粘附和运动协调的方法，包括那些形成工业和医学上重要的抗流动生物膜的细菌。