Intergeneric Signaling Molecules of S. cristatus

描述：牙菌斑(生物膜)已被认为是成人牙周病的主要致病因素。导致该疾病发生的关键事件是从共生牙科生物膜向致病生物膜的转变。众所周知，过渡过程涉及几种特殊的牙周病原体的定植，如牙龈卟啉单胞菌。其长期目标是了解导致健康菌斑向病理性菌斑转化的事件和因素，并通过防止牙龈假单胞菌附着来改变牙周病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FIMA基因的表达，FIMA基因是一种编码菌毛的主要蛋白质单位(菌毛蛋白)的毒力基因。一个引人注目的发现是，暴发性链球菌分子(S)的存在可以在转录水平显著抑制FIMA在牙龈假单胞菌中的表达。结果表明，金黄色葡萄球菌在体外可抑制牙龈假单胞菌生物被膜的形成。在这项拨款申请中，我们将把重点放在从生物化学和遗传学的角度对S.criatus信号分子进行表征。对于这一应用的假设是，犯罪链霉菌通过属间信号系统在阻止牙龈假单胞菌在牙科生物膜上定植方面发挥重要作用。为了验证这一假说，我们将从鉴定和纯化鸡冠状病毒信号分子(S)开始。信号分子将在功能和遗传结构方面进行表征。我们还将试图了解口腔生物膜中信号基因表达的调节。因此，将克隆鸡冠状芽胞杆菌信号转导基因。该基因的启动子区域将与报告基因如氯霉素乙酰转移酶基因融合，并通过测定酶活性来确定基因的表达水平。最后，我们将研究该分子在致病口腔生物膜形成中的作用。将启动研究，以确定信号分子在健康受试者和牙周炎患者牙菌斑中的分布。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，这些技术可用于重新编程牙科生物膜的发展，并减少成人牙周炎的发生率。

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.