ORAL BIOFILMS: DIFFERENTIAL DISPLAY AND GENETIC EXCHANGE

成人牙周炎是一种生物群移位性疾病，由牙菌斑的生态转变引起，并由此导致慢性炎症。因此，了解牙菌斑的生理学及其复杂的生态学，使其达到可控制的程度，是预防和治疗牙周病的核心。牙菌斑是一种生态复杂的生物膜，有350多个微生物分类群，但生物膜的组织并不是随机的。口腔链球菌，包括戈登链球菌，是最早在被覆膜的牙齿表面定居的细菌之一，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，先锋物种如戈登螺旋藻对牙齿表面的初始结合在建立与牙龈健康和疾病相关的生态群落方面起着关键作用。这一提议的中心假设是，在牙菌斑生物膜中，细菌是有知觉的，并通过接收、传输和对化学和物理信号的反应来促进其维持、生理和发育。因此，拟议研究的目标是开发和使用一种优化的差异显示方法和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菌落形成的细菌之间的关键通信，2)确定细菌对环境线索的反应，其中包括来自其他细菌物种以及宿主的信号，以及3)确定生物膜形成对另一种形式的细胞间通信--遗传交换的影响。这项研究的实际好处是，它可能导致新的策略来颠覆或调节口腔生物膜形成中的关键相互作用，从而产生新的治疗方法来控制口腔生物膜的建立，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.