甘肃特有少数民族龋病相关微生物的生态遗传特征研究

Dental caries indeed does harm to the oral health of human beings and it is also a hazardous factor which can give rise to various systemic diseases.Synthetically studying the pathogenesis of dental caries,from the perspective of microbiological factor, environmental factor and host factor, has become one of the most heated focuses of recent researches and one of research frontiers.We aim at different age groups of the minorities peculiar to Gansu Province（Dongxiang,Baoan and Yugu nationalities）.Here,with Han nationality as the control group in this propject,we will conduct the survey of environmental factors including habit, soil and water quality and the epidemiology of the dental caries ,analyze microbiological community structure in oral cavity by using the technologies of 45Pyrosequencing and RT-qPCR, detect physical and chemical factors of saliva by using the method of Inductively Coupled Plasma-Atomic Emission Spectrometry in order to illustrate the relationship between the microbiological community structure and the physical and chemical factors of saliva.In addition,we will test the differences of different bacterial strains of Streptococcus mutans of the special nationalities from the angle of genomics with the technology of suppression subtractive hybridization. In the meanwhile, we will observe the effects of the trace elements on molecular evolution and genetic characteristics of gene brpA on Streptococcus mutans ,which may reveal genetic characteristics of bacterial strains of microorganism contributing to dental caries in groups of the minorities peculiar to Gansu Province.We could illustrate the relationship among environmental factors,the prevalence of dental caries,oral microbiological community structure, physical and chemical factors of saliva and host factor so as to provide the theoretical basis for the ecological prevention of dental caries and the preventive decision made to control the prevalence of dental caries.

龋病严重危害口腔健康。从微生物因素、环境因素、宿主因素等方面综合研究龋病的发病机制是口腔生态学领域的研究热点及前沿之一。本项目拟以汉族为对照，针对甘肃特有少数民族（东乡、保安及裕固族）不同年龄组人群，进行土壤、水质及生活习惯等环境因素调查与龋病流行病学调查；利用454焦磷酸测序和RT-qPCR技术分析他们的龋病相关微生物群落结构、ICP-AES法检测唾液理化因素，阐述龋病相关微生物群落结构与唾液理化因素之间的关系；筛选出甘肃特有少数民族龋病典型致病微生物后，利用SSH技术对其进行不同菌株基因组学差异的检测，同时观察微量元素对其耐酸相关基因作用的分子演变和遗传特征的影响，以揭示甘肃特有少数民族人群致龋微生物菌株生态遗传学特征。阐明环境因素、龋病发病、龋病相关微生物群落结构、唾液理化因素以及宿主因素之间的关系，为生态防治龋病、制定龋病的预防决策提供理论依据。

龋病是口腔内最常见的疾病之一，微生物作为公认的致龋因素，在龋病发生过程中起着关键作用。本课题首先针对甘肃特有少数民族，进行环境因素调查与龋病流行病学调查及样本采集；然后采用高通量测序对保安族受试人群的唾液样本进行微生物群落结构多样性分析，测定样本pH及铁元素含量并分析唾液微生物群落结构多样性与pH、铁元素的相关性，并以保安族儿童为研究对象，通过构建细菌16SrRNA克隆文库，从不同的分类学水平，对比、分析龋病组和无龋组的微生物群落结构差异。同时以变异链球菌CSP的C端16个氨基酸序列(CSPC16)为KH区域，以人源抗菌肽LL-37的整条氨基酸序列为AMP区域，两者通过连接体(-GGG-)连接，合成人源特异性靶向抗菌肽C16LL-37并对其生物学特性进行研究。. 结果表明，龋病人群唾液微生物群落关系可能表现为互利共生；微生物群落结构与环境因素密切相关，可能受到pH环境及铁元素的影响；龋病的发病原因可能是微生物群落结构多样性、唾液酸碱性、微量元素等多因素综合作用的结果。保安族儿童口腔唾液微生物群落结构较为丰富，在口腔微生态系这个复杂的环境中，尚有很多细菌在龋病发生中所发挥的作用需要深入研究，如罗氏菌属、Aggregatibacter菌属等；16SrRNA克隆文库法是一种较成熟且全面的研究方法，有利于口腔微生物群落结构多样性的研究。在实验室人工合成的人源特异性靶向抗菌肽C16LL-37C16LL-37对变异链球菌具备显著的靶向特异性及较强的抗菌活性，且具有较高的生物安全性及良好的稳定性。. 上述结果为进一步研究该地区龋患人群口腔中的主要致龋微生物以及微生物的致龋机制提供数据支持，同时阐明环境因素、龋病发病、龋病相关微生物群落结构、唾液理化因素以及宿主因素之间的关系，为生态防治龋病、制定龋病的预防决策提供理论依据。人源特异性靶向抗菌肽的成功合成也为人类龋病的防治及相关药物的开发奠定了一定的基础。

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