Oral Biofilm Dispersal Strategies

人类口腔中含有超过750种细菌物种的物种丰富的微生物群，其中大多数作为牙菌斑生物膜嵌入细胞外聚合物物质中。在这种复杂和竞争性环境中的微生物经历持续的压力和波动：氧的可用性，pH值，氧化还原电位，盐度，水和唾液的生化活性的变化，短期极端温度条件，有时营养饥饿和营养丰富的时期。由于这种环境的不稳定性，成功的微生物占据依赖于两个主要策略：i）建立特定的细胞-细胞相互作用，导致种内相互依赖，以及ii）在作为牙菌斑的寄生生物膜中的巩固。为了表征微生物分散事件的特征，我们选择了一个模型财团的三个公认的口腔细菌称为红色复合体，其中包括牙龈卟啉单胞菌，Tannerella denticola和密螺旋体。我们的研究将集中在两类酶，已牵连在生物膜分散在其他壁龛，包括碳水化合物分散和细胞外核酸酶，与工作的假设，他们可能是负责红色复杂的生物膜重塑。为了实现这一目标，并把我们的结果纳入生物学背景下，我们将实施一个自下而上的方法的结构和功能表征的酶，可能有助于生物膜分散，以及自上而下的方法跟踪这些酶的影响，通过微流体，在体外分析生物膜形态。一般来说，生物膜分散过程的表征很有可能告知细菌生命周期中的独特状态。据我们所知，我们的实验方法来表征基石生物膜分散口腔微生物组是独一无二的在加拿大。

The human oral cavity harbours a species-rich microbiota of greater than 750 bacterial species, the majority of which are embedded in an extracellular polymeric substance as dental plaque biofilms. Microorganisms in this complex and competitive environment experiences continuous stress and fluctuations: oxygen availability, changes in pH, redox potential, salinity, water and biochemical activity of saliva, short term extreme temperature conditions, and at times nutrient starved and nutrient rich periods. Because of this environmental instability, successful microbial occupation relies on two principal strategies: i) establishment of specific cell-cell interactions that lead to intraspecies co-dependence, and ii) entrenchment in recalcitrant biofilms as dental plaque. To characterize the features of microbial dispersive events, we have selected a model consortium of three well recognized oral bacteria known as the red complex, which consists of Porphyromonas gingivalis, Tannerella forsythia and Treponema denticola. Our research will focus on two classes of enzymes that have been implicated in biofilm dispersal in other niches including carbohydrate-dispersins and extracellular nucleases, with a working hypothesis that they may be responsible for red complex biofilm remodelling. To achieve this goal, and to put our results into biological context, we will implement a bottom-up approach of structural and functional characterization of enzymes that may contribute to biofilm dispersal, as well as a top-down approach of tracking the impacts of these enzymes to biofilm morphology through microfluidic, in vitro analyses. In general, the characterization of biofilm dispersal processes have a strong likelihood to inform a unique state in the bacterial lifecycle. To our knowledge, our experimental approach to characterize keystone biofilm dispersal by the oral microbiome is unique in Canada.