Streptococcus-Candida Communication in Oral Biofilms

描述(申请人提供)：牙菌斑生物膜是在口腔表面发现的多菌群落，嵌入宿主唾液成分和微生物胞外产物的基质中。这些生物膜为口腔软硬组织疾病提供了感染源。微生物之间的通讯反应调节着生物膜的结构、组成和致病潜力。口腔链球菌在这方面尤其重要，因为它们是口腔表面的主要定殖者。它们的沉积为潜在致病生物的定居提供了附着底物，例如白色念珠菌，这是人类大多数酵母感染的原因。口腔链球菌和白色念珠菌之间的共黏附被认为是为了促进白色念珠菌的口腔携带和持久性，从而导致诸如义齿诱导的口腔炎等疾病。研究表明，戈登链球菌和白色念珠菌之间的微生物结合涉及互补和协同的粘附素受体分子。链球菌细胞表面相关抗原I/II家族粘附素，命名为SSPA和SspB，靶向酵母细胞表面受体，导致其他表面分子与配对细胞类型的紧密结合。这些附着过程推动了混合物种生物膜的发展和积累，这些生物膜在形态、生理和病原学上都是独一无二的。本研究的目的是：鉴定白色念珠菌对戈登葡萄球菌SspB蛋白的受体；确定L/111家族蛋白识别酵母受体的分子基础；研究底物组成、环境因素和链球菌粘附素表达对戈登葡萄球菌-C的影响。白念珠菌混合生物被膜；确定戈登葡萄球菌和白念珠菌在生物被膜中的差异基因表达模式，并通过细胞-细胞接触诱导。这些实验将提供关于介导戈登葡萄球菌和白色念珠菌相互作用的主要成分的详细分子信息，并更好地了解共粘着导致生物膜成熟的信号和途径。这些信息将有助于制定更有效的基于生物学的战略，以控制多微生物生物被膜，并用于治疗性预防白色念珠菌过度生长。念珠菌感染对公众健康构成严重威胁。本研究为控制或预防口腔内念珠菌的生长提供了新的方法。

DESCRIPTION (provided by applicant): Dental plaque biofilms are polymicrobial communities found on oral surfaces embedded in a matrix of host salivary components and microbial extracellular products. These biofilms provide an infection source for diseases of the oral hard and soft tissues. Communication reactions between the micro-organisms modulate the structure, composition and pathogenic potential of the biofilms. The oral streptococci are especially important in this respect because they are primary colonizers of oral cavity surfaces. Their deposition provides an attachment substrate for colonization by potentially pathogenic organisms such as the fungus Candida albicans, which is the cause of most yeast infections in humans. Co-adhesion between oral streptococci and C. albicans is proposed to facilitate oral carriage and persistence of C. albicans, leading to disease conditions such as denture-induced stomatitis. Studies have demonstrated that inter-microbial binding of Streptococcus gordonii and C. albicans involves complementary and co-operative adhesin- receptor molecules. Streptococcal cell surface-associated antigen I/II family adhesins, designated SspA and SspB, target yeast cell surface receptors, resulting in close engagement of other surface molecules on the partner cell types. These adhesion processes drive the development and accumulation of mixed species biofilms that are morphologically, physiologically and pathogenically unique. The objectives of this application are to: identify the C. albicans receptor for the SspB protein of S. gordonii; define the molecular basis of yeast receptor recognition by antigen l/ll family proteins; investigate the effects of substratum composition, environmental factors and the role of Streptococcal adhesin expression on the development of S. gordonii-C. albicans mixed biofilms; determine patterns of differential gene expression in S. gordonii and C. albicans in biofilms and induced by cell-cell contact. These experiments will provide detailed molecular information on the major components mediating interactions of S. gordonii and C. albicans and better understanding of the signals and pathways by which co-adhesion leads to biofilm maturation. Such information will assist in the development of more effective biologically based strategies for control of polymicrobial biofilms, and for therapeutic prevention of C. albicans overgrowth. Candida yeast infections are a serious threat to public health. This research devises new methods for controlling or preventing growth of Candida in the mouth.