Intergeneric Signaling Molecules of S. cristatus

描述：牙菌斑（生物膜）被认为是成人牙周病的主要病因。导致疾病开始的关键事件是由牙周生物膜向致病生物膜的转变。众所周知，转化过程涉及几种特定牙周病原体如牙龈卟啉单胞菌的定殖。长期目标是了解导致健康菌斑转化为致病菌斑的事件和因素，并通过防止牙龈卟啉单胞菌附着来改变牙周致病生物膜的发展过程。在我们正在进行的研究中，我们已经确定了几个环境因素，可以影响表达的fimA基因，编码菌毛的主要蛋白单位（fimbrillin）的毒力基因。一个引人注目的发现是，冠状链球菌分子的存在可以在转录水平上显著抑制牙龈卟啉单胞菌中的fimA表达。因此，S. cristatus能抑制牙龈卟啉单胞菌生物膜的形成。在这个基金申请中，我们将把我们的重点放在表征S。cristatus信号分子，生化和遗传。该应用的假设是S. cristatus通过属间信号系统在阻止牙龈卟啉单胞菌在生物膜上定植中发挥重要作用。为了验证这一假设，我们将从鉴定和纯化S.鸡冠。信号分子将在功能和遗传结构方面进行表征。我们也将试图了解口腔生物膜中信号基因表达的调控。因此，S. cristatus将被克隆。该基因的启动子区将与报告基因如氯霉素乙酰转移酶基因融合，并通过测量酶活性来确定基因表达水平。最后，该分子在致病性口腔生物膜形成中的作用将被研究。将开始研究以确定来自健康受试者和牙周炎患者的牙菌斑中的信号分子的分布。我们的最终目标是将从这些实验室研究中获得的知识转化为实用技术，可用于重新编程牙齿生物膜的发展并降低成人牙周炎的发病率。

DESCRIPTION: Dental plaque (biofilm) has been implicated as a primary causative agent of adult periodontal disease. The key event leading to initiation of the disease is the transition from commensal Dental biofilm to pathogenic biofilm. It is well known that the process of the transition is involved in the colonization of several specific periodontal pathogens such as Porphyromonas gingivalis. The long-range goal is to understand events and factors leading to the transformation of healthy plaque to pathogenic plaque and to change the course of development of periodontopathogenic biofilm by preventing attachment of P. gingivalis. In our ongoing studies, we have identified several environmental factors that can influence expression of fimA gene, a virulence gene encoding a major protein unit (fimbrillin) of fimbriae. One of the striking findings is that the presence of Streptococcus cristatus molecule(s) could significantly repress fimA expression in P. gingivalis at the transcriptional level. As a result, S. cristatus could inhibit the formation of P. gingivalis biofilm in vitro. In this grant application, we will put our focus on characterization of S. cristatus signaling molecule, biochemically and genetically. The hypothesis for this application is that S. cristatus plays an important role in impeding P. gingivalis' colonization on Dental biofilm through intergeneric signaling systems. To test this hypothesis, we will start with identification and purification the signaling molecule(s) of S. cristatus. The signaling molecule will be characterized in the terms of functional and genetic structures. We will also attempt to understand regulation of the signaling gene expression in oral biofilm. Therefore, the signaling gene of S. cristatus will be cloned. The promoter region of the gene will be fused with the reporter gene such as chloramphenicol acetyltransferase gene, and level of the gene expression will be determined by measuring enzymatic activity. Finally the role of this molecule in the formation of pathogenic oral biofilm will be investigated. Studies will be initiated to determine the distribution of the signaling molecule in the Dental plaques from healthy subjects and periodontitis patients. Our ultimate goal is to convert the knowledge gained from these laboratory studies to practical technology that may be used to reprogram development of the Dental biofilm and to reduce the incidence of adult periodontitis.