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：螺旋体是侵入性的，快速移动的革兰氏阴性细菌，具有螺旋波或平面波形形状，内部周质鞭毛，将细胞体包裹在细胞体周围，并通过促进细胞体的波动波或开瓶器样旋转来驱动运动，而流体外膜含有较少的跨膜外膜。大多数螺旋体粘附蛋白（粘附素）被脂质锚锚定在外膜上，并且可能是高度移动的。螺旋体在密集的生物材料中移动的速度比纯液体更快，这可能是由于细胞及其细胞外环境之间的牵引粘合剂相互作用而导致的，这对于其他细菌无法接近的环境可能至关重要。如果运动能力取决于粘附，那么粘附素也可能是流动性的，尤其是在诸如对表面的粘附条件之类的条件下，随着粘附复合物将细菌锚定在表面上，细菌运动和流动促进细胞体的前进。在存在和不存在流动的情况下，螺旋体粘附和运动的动态配位的性质和机制尚未定义，并且尚未针对大多数细菌定义。这在很大程度上是由于需要开发快速，高分辨率的活细胞成像工具来研究粘附和运动的协调。我的实验室是开发基于成像的方法，用于研究流动和非流动环境中细菌粘附，运动性和运动的方法，并最近建立了第一个基于成像的粒子跟踪和生物物理分析工具来研究细菌粘附和流动表面的运动。我们主要与莱姆病螺旋菌伯氏毛毛毛毛（BB）一起鉴定了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，并出乎意料地发现，BB运动刺激并稳定在流动下与内皮细胞的BB相互作用。 研究计划的总体目标：研究BB粘附和运动的基本特性和机制。短期目标：开发基于快速的，基于细胞成像的快速现场成像方法来研究粘附和运动的细菌协调。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，以及如何协调粘附和运动。 意义：这些研究将提供对螺旋体运动和粘附的机制的首次动态见解。这项研究将对加拿大微生物学家具有基本的，非健康相关的兴趣，尤其是因为它将建立用于研究其他细菌的粘附和运动能力的方法，包括那些在工业上形成工业和医学上重要的流动性生物膜。