ORAL BIOFILMS: DIFFERENTIAL DISPLAY AND GENETIC EXCHANGE

成人牙周炎是一种由牙菌斑生态转移引起的生物群转移疾病，随之而来的是慢性炎症。因此，了解牙菌斑的生理学及其复杂的生态学，并将其控制到可以控制的程度，对于预防和治疗牙周病至关重要。牙菌斑是一种生态复杂的生物膜，有350多个微生物类群；然而，生物膜的组织并不是随机的。口腔链球菌，包括戈多氏链球菌，是最早在被膜覆盖的牙齿表面定植的细菌之一，为随后附着的其他细菌物种创造了一个模板，最终包括牙周病原体。因此，由先驱物种（如s.g ordonii）对牙齿表面的初始结合对于建立与牙龈健康和疾病相关的生态群落至关重要。该建议的中心假设是，在牙菌斑生物膜内，细菌是有知觉的，并通过接收、传递和响应化学和物理信号来促进其维持、生理和发育。因此，提出的研究目标是开发和使用一种优化的差分显示方法，以及扫描激光共聚焦显微镜，以：1)确定在模型生物膜中调节生长和微集落形成的细菌之间的关键通信；2)确定细菌对环境信号的反应，包括来自其他细菌物种和宿主的信号；3)确定生物膜形成对细胞间通信的另一种形式——遗传交换的影响。这项研究的实际好处是，它可能会导致颠覆或调节口腔生物膜形成中的关键相互作用的新策略，从而导致控制其建立的新疗法，使其对抗生素敏感，并促进其去除。

Adult periodontitis is a biota shift disease caused by an ecological transition of the dental plaque, and consequent chronic inflammation. Understanding the physiology of dental plaque and its complex ecology, to the point where it can be controlled, is therefore central to the prevention and treatment of periodontal disease. Dental plaque is an ecologically complex biofilm with over 350 microbial taxa represented; however the organization of the biofilm is not random. Oral streptococci, including Streptococcus gordonii, are among the first bacteria to colonize the pellicle coated tooth surface, creating a template for the subsequent attachment of other bacterial species, ultimately including periodontal pathogens. The initial binding of the tooth surface by pioneer species, such as S. gordonii, is therefore pivotal in the establishment of ecological communities associated both with gingival health and disease. The central hypothesis of this proposal is that within the dental plaque biofilm, bacteria are sentient and contribute to its maintenance, physiology, and development through receipt, transmission and response to chemical and physical signals. The goals of the proposed study are therefore to develop and use an optimized differential display approach, and scanning laser confocal microscopy, to: 1) identify the critical communications between bacteria that regulate growth and microcolony formation in a model biofilm, 2) identify bacterial responses to environmental cues, which include signals derived from other bacterial species as well as the host, and 3) determine the effect of biofilm formation on an additional form of intercellular communication, genetic exchange. The practical benefit of this study is that it may lead to new strategies for subverting or regulating key interactions in oral biofilm formation, and therefore to new therapies for controlling its establishment, rendering it sensitive to antibiotics, and facilitating its removal.