Detection Of Mutation In The Acid-resistant Gene AtpABCDEFGH Of Fluoride-resistant Strain Of Streptococcus Mutans And Clinical Signiifcance

Objective:Caries is one of the three major diseases endangering our health, is akind of chronic progressive infectious diseases. It generally occurs in allgroups.Among various kinds of risk factors, plaque,where a variety ofbacteria survive,is the main cause of tooth decay, in which streptococcusmutans acts as the main pathogenic bacteria, closely related to theoccurrence and development of caries.Since the1940s, people havestarted to use fluoride to prevent caries.Fluoride functions mainly bypreventing demineralization and promoting mineralization of enamel.Atthe same time,fluoride can inhibit the growth and acid production ofbacteries.The curative effect of fluoride becomes not good untilfluoride-resistant strains of streptococcus mutans exist in the oralenvironment. F0F1-ATPase is a kind of function protein which iscomposed of two different domains.It works as a pump that can pump theproton out of cell with the energy of ATP hydrolysis.So the intracellularPH maintains stable,making the strptococcus mutans survive in the acidicenvironment.Scholars from home and abroad have full proof thatfluoride-resistant strains of streptococcus mutans have stronger cariosityand resistance to fluoride.Detection of mutation in the acid-resistantgenes dltC，Dgk，comD and ccpA of the fluoride-resistant strains ofstreptococcus mutans indicates that there are mutations.We try to detectthe mutation in the acid-resistant genes atpABCDEFGH of thefluoride-resistant strains of streptococcus mutans, providing the theoretical foundation to the development of more effective methods ofcuring caries.Materials and Methods:1.Identifying the fluoride-resistant strain of Streptococcus mutansUA159.2.Extraction of the genome DNA of UA159-FR.3.The purpose of PCR amplification genes4. The construction of a recombinant plasmid: connecting the genesand PMD-19T vector,transforming it into E.coli cells.5. Extracting the plasmid,identifying the gene we need.6. Sendingfor sequencing.Result:1. Successfully identifying UA159-FR.2.Successfully construct the recombinant plasmid.3.By using the BLAST tool to compare the homology of theobtained comD and gbpB genes sequences in the GenBank datebase.Wefound that the acid resistance related geneConclusion:Successfully built the recombinant plasmids of the acid-resistantgenes comD and gbpB mutations of the fluoride-resistant strain ofstreptococcus mutans in competent cell E.coli JM109and indentifiedthem by PCR，enzyme digestion and gene sequencing.The research is ofgreat importance for preventing and controlling the caries disease in thefuture.