Molecular Forces in Microbial Biofilms

NSERC的这项发现拨款提案寻求发现稳定各种表面上微生物生物膜形成的分子作用力的潜在机制。微生物生物膜在加拿大几个部门(如食品安全、农业、工业和石油管道、船体涂层等)的大多数主要污染问题中发挥着核心作用，估计每年花费数十亿美元。这种与生物膜相关的问题日益严重的一个关键原因是我们对细菌附着在广泛表面的机制了解有限，以及负责稳定这些生物膜的力量背后的分子理解不足。由于细菌在表面的初始黏附和微菌落形成是成熟生物膜的关键先决条件，本研究计划将针对生物膜形成的初始阶段，并将重点放在在生物膜发展的这些关键阶段赋予生物膜稳定性的“分子作用力”。特别是，它的目的是剖析细菌表面黏附分子和底层底物属性之间的纳米级相互作用，初步解决底物硬度对大肠杆菌生物膜生长的影响。虽然底物硬度长期以来一直被认为是影响哺乳动物细胞信号和干细胞分化的因素，但它对微生物生物膜生长的影响是一个相当新的发现，还没有被很好地了解。为了填补底物硬度如何影响稳定生物膜的分子力的空白，我的实验室将率先在扫描探针显微镜、光学显微镜和力光谱之间进行三向相关测量，具有单分子和单细胞分辨率。这种定量和相关的生物膜研究方法不仅将提供生物膜复杂结构的高分辨率图像，而且还将量化稳定这些结构的纳米级力量。长期目标是扩大研究范围，以涵盖其他底物特性和其他生物膜形成细菌。这将为底物的物理化学特性如何影响赋予生物膜稳定性的分子作用力提供更一般的机械洞察。这一研究项目的结果不仅将加深我们对生物膜在不同表面上附着的结构稳定性的机械理解，还将为加拿大与农业、能源、环境和公共卫生相关的行业以及全球人口带来实实在在的好处，特别是在抗菌素耐药性生物日益威胁的情况下。此外，由于这项研究的跨学科性质，它将成为下一代加拿大科学家的极好培训基地，并将把加拿大带入定量生物膜研究的前沿。

This NSERC discovery grant proposal seeks to discover mechanisms underlying the molecular forces that stabilize microbial biofilm formation on a wide variety of surfaces. Microbial biofilms play a central role in most major fouling problems in several sectors in Canada (e.g. food safety, agriculture, industrial and oil pipelines, ship hull coatings etc.), and is estimated to cost billions of dollars annually. A key reason behind this growing biofilm-related problems is our limited understanding of the mechanisms by which bacteria adhere to a wide range of surfaces, and the lack of molecular understanding behind the forces responsible for stabilizing these biofilms. As initial adhesion and microcolony formation of bacteria on surfaces are crucial pre-requisites for mature biofilms, this research program will target the initial stages of biofilm formation, and will focus on the “molecular forces” that confer biofilm stability during these critical phases of biofilm development. In particular, it aims to dissect the nanoscopic interplay between bacteria's surface adhesion molecules and the properties of the underlying substrate, initially addressing the influence of substrate stiffness on the growth of E. coli biofilms.While substrate stiffness has long been established to influence mammalian cell signalling and stem cell differentiation, its influence on microbial biofilm growth is rather a recent discovery and is not yet well understood. In order to fill the gap on how substrate stiffness affects the molecular forces that stabilize biofilms, my lab will pioneer a three-way correlated measurements between scanning probe microscopy, optical microscopy, and force spectroscopy, with single-molecule and single-cell resolution. This quantitative and correlated approach to biofilm study will not only provide high-resolution images of the biofilm's complex structures, under physiological conditions, it will also quantify the nanoscale forces that stabilize these structures. The long-term goal is to expand the research to cover other substrate properties, and other biofilm-forming bacteria. This will provide a more general mechanistic insights into how the physico-chemical characteristics of the substrate influence the molecular forces that confer biofilm stability.Results from this research program will not only further our mechanistic understanding of the biofilm's structural stability in adhering to different surfaces, it will also lead to tangible benefits to Canadian industries related to agriculture, energy, environment, and public health, and to the global population, especially with the growing threat of antimicrobial-resistant organisms. Furthermore, with the interdisciplinary nature of the research it will be an excellent training ground for the next generation of Canadian scientists, and will bring Canada at the forefront of quantitative biofilm research.