REPLACEMENT THERAPY OF DENTAL CARIES

替代疗法已被证明在啮齿类动物中成功地用于 预防龋齿。 本申请描述了设计的研究 发展预防龋齿的替代疗法， 人类 目标1和2的目的是进一步了解 生理学和生态学参数， 构建一种既无毒力又能够 有效地在人类口腔中定植。 这些研究将涉及 准确分析野生型和乳酸菌的发酵模式 葡萄糖苷酶缺陷型S.变异体，以及可遗传变化的识别 在人类口腔的长时间定殖期间发生， 帮助适应S.变种人适应这种环境 从信息 将分离获得的理想效应菌株。 他们将接受考验 在目标3中，使用无菌和常规大鼠模型， 致龋潜力 效应菌株先发制人的能力 在啮齿类动物的口腔中定居， S.将在目标4中测试变异体。 一株S.产生一种 一种异常有效的细菌素将作为这些细菌的起始菌株， 问题研究 在目标5中，获得高感染率所需的最低感染方案 该菌株在人体内的定殖水平将在一个 涉及3名受试者的临床初步研究。 的微生物检验 这些受试者的唾液和牙菌斑将用于确定 的效应菌株对土著S.变异人种群和 一般菌斑微生物区系。 该菌株产生的细菌素含量为0.01%~ 0.01%。 变形菌作为局部抗龋齿剂是有意义的。 在目标6中， 对于它的纯化、测序和体外合成进行了开发， 使用常规的生物化学和重组DNA技术。 要求7 包括直接证明细菌素和细菌素的作用的研究， 生态决定因子 细菌素也将在啮齿动物中进行测试 作为局部抗龋齿剂的能力的模型。

Replacement therapy has been shown to work successfully in rodents for the prevention of dental caries. This application describes studies designed to develop replacement therapy for the prevention of dental caries in humans. The purpose of Aims 1 and 2 is to further understand the physiology and ecological parameters of Streptococcus mutans in order to construct an effector strain that is both non-virulent and capable of efficiently colonizing the human oral cavity. These studies will involve accurate analysis of the fermentation patterns of wild-type and lactate dehydrogenase-deficient S. mutans, and identification of heritable changes that occur during prolonged colonization of the human oral cavity which help to adapt S. mutans to that environment. From the information obtained, idealized effector strains will be isolated. They will be tested in Aim 3, using gnotobiotic and conventional rat models, for their cariogenic potential. The ability of the effector strains to preemptively colonize the oral cavities of rodents, and displace indigenous strains of S. mutans will be tested in Aim 4. A strain of S. mutans that produces an unusually potent bacteriocin will serve as the starting strain for these studies. In Aim 5 the minimum infection regimen required to obtain high levels of colonization by this strain in humans will be examined in a clinical pilot study involving 3 subjects. Microbiological analysis of saliva and plaque from these subjects will be used to determine the effects of the effector strain on indigenous S. mutans populations and on the general plaque microflora. The bacteriocin produced by this strain of S. mutans is of interest as a topical anti-caries agent. In Aim 6, methods for its purification, sequencing, and in vitro synthesis are developed, using both conventional biochemical and recombinant DNA technology. Aim 7 involves studies to directly demonstrate the role of the bacteriocin an an ecological determinant. The bacteriocin will also be tested in a rodent model for its ability to serve as a topical anti-caries agent.