Cell-cell Interactions Between Oral Actinomyces And Othe

口腔放线菌与其他细胞之间的相互作用

• 批准号: 7006927
• 负责人: PAUL E KOLENBRANDER
• 金额: --
• 依托单位: NATIONAL INSTITUTE OF DENTAL & CRANIOFACIAL RESEARCH
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7006927
• 关键词: Actinomyces; Fusobacterium nucleatum; biofilm; biological signal transduction; cell cell interaction; confocal scanning microscopy; dental plaque; gene expression; human subject; microorganism culture; microorganism interaction; oral bacteria; saliva

Mixed-species communities of microbes are examples of genome-genome interactions. Such communities in the human oral cavity form dental plaque. We are expanding our previous studies that demonstrated initial dental plaque is composed of several kinds of interacting cells. During this reporting period, novel plasmids for use in Fusobacterium nucleatum, an oral microbe that interacts with a wide variety of other human oral bacteria including initial colonizers such as oral streptococci and actinomyces, have been developed. We hypothesize that dental plaque communities initiate through intimate interactions between cells (genomes) of different species and not by clonal growth of genetically identical cells. The human oral cavity provides easy access to natural biofilms on a retrievable enamel chip, which is an excellent model to study genome-genome interactions. To complement our studies of initial oral microbial communities formed on the retrievable enamel chip, we tested the role of cell-cell interactions in forming multispecies communities in a saliva-conditioned in vitro flowcell. We had shown previously that a pair of streptococcal and actinomyces species exhibited mutualism when grown together on saliva as the sole nutrient source; individually neither species could grow on saliva. In this reporting period, we extended this aspect of the study to examine a community of four oral bacterial species for additional potential for mutualism when grown in a flowcell with saliva as the sole source of nutrition. All four species interacted and formed mixed-species communities. Again two species were found to mutually benefit by being inoculated together into the flowcell, suggesting that oral bacteria communicate through close contact and metabolic products. We have continued our studies on early colonizing streptococci. In this reporting period, we examined the effects of antimicrobial agents on a streptococcal biofilm grown in a saliva-conditioned flowcell. The flowcell coupled with confocal laser microscopy enabled examination of growing oral biofilms in situ without disruption of the microbial community. Biofilms composed of oral streptococci were grown in the flowcell and treated with several commercially available antimicrobial mouthrinses. The results of this study revealed varying abilities of the antimicrobial agents to cause cellular damage on the growing biofilm in situ, and this study demonstrated the usefulness of the flowcell in the rapid assessment of antimicrobial efficacy. We are continuing our investigations of cell adherence molecules, cell signaling molecules, gene expression within human oral biofilms, and of the relevance of these events to bacterial community architecture. Our hypothesis is that signaling molecules involved in cellular communication impact the spatiotemporal development and establishment of dental plaque as well as colonization of the host. One pair of early colonizing species includes streptococci which ferment complex carbohydrates and sugars to lactic acid, which is the preferred substrate for growth by veillonellae. Initial results obtained during this reporting period suggest that veillonellae send a signal to streptococci that induces the expression of a gene encoding an amylase. Microbial diversity and accessibility make dental plaque communities very attractive for the study of genome-genome interactions, which might occur at multiple levels including physical, metabolic, and genetic. We emphasize here the importance of determining first the physical interactions occurring in vivo between cells of different species and genera in order to design the correct in vitro studies to determine potential metabolic exchange between species. Our long-range goal is to understand the molecular mechanisms of cellular communication and their relationship to the spatiotemporal development and establishment of dental plaque andd colonization of the host epithelial cells.

微生物的混合物种群落是基因组-基因组相互作用的例子。人类口腔中的这些群落形成牙菌斑。我们正在扩展我们以前的研究，证明最初的牙菌斑是由几种相互作用的细胞组成的。在本报告期间，开发了用于具核梭杆菌的新型质粒，具核梭杆菌是一种与多种其他人类口腔细菌相互作用的口腔微生物，包括初始定殖菌，如口腔链球菌和放线菌。我们假设牙菌斑群落是通过不同物种的细胞（基因组）之间的密切相互作用而启动的，而不是通过遗传相同的细胞的克隆生长。人类口腔提供了在可回收的釉质芯片上容易获得的天然生物膜，这是研究基因组-基因组相互作用的极好模型。 为了补充我们对可回收釉质芯片上形成的初始口腔微生物群落的研究，我们测试了细胞-细胞相互作用在唾液调节的体外流动池中形成多物种群落的作用。我们之前已经证明，当一对链球菌和放线菌物种在唾液作为唯一营养源的情况下一起生长时，它们表现出互利共生;单独地，这两个物种都不能在唾液上生长。在本报告所述期间，我们扩展了这方面的研究，以检查四种口腔细菌物种的群落，当在以唾液作为唯一营养来源的流动池中生长时，其具有额外的互利共生潜力。四个物种相互作用，形成混合物种群落。再次发现两个物种通过一起接种到流通池中而相互受益，这表明口腔细菌通过密切接触和代谢产物进行交流。 我们继续对早期定植链球菌进行研究。在本报告期内，我们研究了抗菌剂对唾液条件流通池中生长的链球菌生物膜的影响。流动池与共聚焦激光显微镜相结合，能够原位检查生长的口腔生物膜，而不会破坏微生物群落。由口腔链球菌组成的生物膜在流通池中生长，并用几种市售的抗微生物漱口水处理。该研究的结果揭示了抗菌剂在原位生长的生物膜上引起细胞损伤的不同能力，并且该研究证明了流通池在快速评估抗菌功效中的有用性。 我们正在继续我们的调查细胞粘附分子，细胞信号分子，人类口腔生物膜内的基因表达，以及这些事件与细菌群落结构的相关性。我们的假设是，参与细胞通讯的信号分子影响时空的发展和建立牙菌斑以及定植的主机。一对早期定植的菌种包括链球菌，其将复合碳水化合物和糖发酵成乳酸，乳酸是韦荣球菌生长的优选底物。本报告期间获得的初步结果表明，韦荣菌素向链球菌发送信号，诱导编码淀粉酶的基因表达。微生物多样性和可及性使得牙菌斑群落对于基因组-基因组相互作用的研究非常有吸引力，基因组-基因组相互作用可能发生在多个水平，包括物理，代谢和遗传。我们在这里强调的重要性，首先确定在体内发生的物理相互作用之间的细胞不同的物种和属，以设计正确的体外研究，以确定潜在的物种之间的代谢交换。我们的长期目标是了解细胞通讯的分子机制及其与牙菌斑的时空发育和建立以及宿主上皮细胞定植的关系。