Microbial Diversity and Genetic Characterization

微生物多样性和遗传特征

• 批准号: 6757189
• 负责人: PAGE W CAUFIELD
• 金额: $ 35.03万
• 依托单位: NEW YORK UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-06-15 至 2007-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6757189
• 关键词: Streptococcus mutans; bacterial genetics; biofilm; clinical research; denaturing gradient gel electrophoresis; dental caries; dental plaque; ecosystem; genetic markers; genetic strain; human subject; nucleic acid probes; nucleic acid sequence; oral bacteria; polymerase chain reaction; preschool child (1-5); ribosomal DNA; ribosomal RNA; subtraction hybridization; transposon /insertion element

The proposed studies are anticipated to yield important new information as to the composition of the bacterial biota that comprises the caries-associated plaque biofilm. The long-term benefit of such information should lead researchers to devising both diagnostic and preventative strategies for dental caries based on addressing its etiological agents. This proposal will focus on children with a severe forms of dental caries called Early Childhood Caries (ECC). Using a powerful technique of gradient electrophoresis will be used to separate 16S rDNA markers from an array of bacteria in plaque biofilms. These gels should show differences between the microfloras of ECC and caries-free children. This profiling, in turn, will allow us to identify or approximate those bacteria, some likely to be uncultivable, associated with caries. Another hypothesis to be tested is whether strains of mutans streptococci, or the entire caries-biofilm differ in their ability to cause disease. Subtraction DNA hybridization will be used to discover unique genetic loci present in mutans streptococci or dental plaques of caries-prone children. Further development of subtraction DNA hybridization will lead to our overall objective, i.e., to characterize from whole plaque a constellation of genetic loci within the caries-active biofilm, irrespective of the limitation of first cultivating specific bacteria. This will set the groundwork for subsequent studies in which a set of DNA probes can be compiled and tested, which will be useful for predicting whether a particular child is at risk for caries. Knowing the function of these genetic loci and the bacterial host from which they arise will give important information as to the causation of caries. Moreover, having genetic markers for disease may eliminate the costly and imprecise practice of cultivating bacteria from dental plaque. The research proposed will likely impact on these more serious forms of caries, leading to its eventual prevention.

拟议的研究预计将产生关于组成与龋齿相关的菌斑生物膜的细菌生物群的重要新信息。这些信息的长期益处应该引导研究人员在解决其病因的基础上，设计出龋齿的诊断和预防策略。这项提案将重点关注患有严重龋齿的儿童，这种龋齿被称为早期儿童龋齿(ECC)。利用一种强大的梯度电泳技术，将从菌斑生物膜中的一系列细菌中分离出16S rDNA标记。这些凝胶应该显示ECC儿童和无龋齿儿童的微生物区系之间的差异。反过来，这种图谱将使我们能够识别或近似那些与龋齿有关的细菌，其中一些可能是不可培养的。另一个需要检验的假设是，变形链球菌菌株或整个龋齿生物膜在致病能力上是否有所不同。消减DNA杂交将被用来发现在易患龋齿的儿童的变种、链球菌或牙菌斑中存在的独特遗传位点。消减DNA杂交的进一步发展将导致我们的总体目标，即从整个菌斑中鉴定出有龋齿活性的生物膜中的一系列遗传位点，而不考虑首先培养特定细菌的限制。这将为随后的研究奠定基础，在这些研究中，可以编辑和测试一组DNA探针，这将有助于预测特定儿童是否有患龋齿的风险。了解这些基因座的功能和它们产生的细菌宿主将为龋病的病因提供重要信息。此外，拥有疾病的遗传标记可能会消除从牙菌斑中培养细菌的昂贵和不精确的做法。这项拟议的研究可能会对这些更严重的龋齿形式产生影响，最终导致其预防。