In Vitro Inhibitive Activity And Composition Analysis Of The Metabolites Of Bacillus Subtilis Isolated From Oral Cavity

Dental caries, which is a infectious disease of dental hard tissue, having a high incidence, wide coverage, can affect people’s health directly or indirectly. However, the existing clinical treatment cannot meet the requirements of prevention and control of caries. Biological replacement therapy, which prevent and control the infectious diseases by colonizing harmless strains into human microflora, have been applied to prevent oral infectious disease. To find out a harmless strains, which can inhibit the major cariogenic bacteria, is a problem to be settled urgently. A large number of studies have shown that, Bacillus subtilis, distributing widely and non-pathogenic, is wildly used in the field of food, industrial, medical, etc. And it is proved that Bacillus subtilis can be isolate in the human oral cavity. Therefore, the aim of this study is to separate Bacillus subtilis from oral cavity, and verify whether its metabolites can inhibit the the cariogenic bacteria, and then analysis its metabolites preliminarily.Methods:The dental plaque was extracted by scratching method, and Bacillus subtilis were then isolated using plate culture method, that were identified through morphology and 16S rDNA gene sequence analysis. The inhibitory activity of the metabolic products against the major cariogenic bacteria were observed by use of the agar well diffusion method. The bacterial metabolites were detected by gas chromatography-mass spectrometer technique and using principal components analysis as clustering analysis method. The mathematical model was established by partial least squares discrimination analysis method and used orthogonal partial least squares discriminant analysis correcting the date. And the results were contradistinguished in KEGG finally.Results:Three strains of bacteria were isolated from the dental plaque, which were identified as Bacillus subtilis through morphology and 16S rDNA gene sequence analysis. The metabolic products show significant inhibitory activity to Streptococcus mutans, Viscous actinomycetes and Lactobacillus acidophilus, especially Viscous actinomycetes. There are 178 kinds of metabolites been found out by gas chromatography-mass spectrometer technique. And each of these can be mapped out in KEGG. Conclusion:Bacillus subtilis can be isolated from the dental plaque, and the metabolic products can inhibit the major cariogenic bacteria. Bacillus subtilis is expected to play an important role in prevention and control of caries disease as an inhibitive bacterium. There are 178 kinds of metabolites been found out by gas chromatography-mass spectrometer technique, which laid a certain foundation for optimization of culture and application of Bacillus subtilis.