Effect Of Fluoride On Biofilm Formation Of The Fluoride-Resistant Strains Of Streptococcus Mutans

Objective:In this experiment,the ideal model of single-bacteria biofilm was constructed to observe the specific process of biofilm formation of Streptococcus mutans fluoride-resistant strains,and the difference of biofilm formation from parental strains was compared.The formation of biofilms of fluoride-resistant strains was observed.The impact of this,laying the foundation for the study of metabolomics.Methods:1?Bacteria:Streptococcus mutans parent strain UA159 and:fluoride-tolerant strain UA159-FR2?Experimental grouping:Parental group(UA group):Streptococcus mutans UA159 was formulated into a bacter:ial suspension in a non-fluorine-containing BHI medium to construct a biofilm;Fluoride-tolerant group'(FR group):Streptococcus mutans UA159-FR is formulated into a bacterial suspension in a non-fluorine-containing BHI medium to construct a biofilm;Fluorine-containing group(FFR group):Streptococcus mutans UA159-FR was formulated into a bacterial suspension in a medium containing 1 g/L of NaF BHI to construct a biofilm.3?experimental method:(1)The differences of biofilm biomass between parental strains and fluoride-tolerant strains were compared by crystal violet staining.The effects of fluoride on biofilm biomass of fluoride-tolerant strains were investigated.The experiment was divided into six time points:(6h,12h,18h,24h,36h,48h).(2)The differences of biofilm morphology between parental strains and fluoride-tolerant strains and the effects of fluoride on the biofilm morphology of fluoride-resistant strains were observed by scanning electron microscopy.The experiment was divided into six periods:6h,12h,18h,24h,36h,48h.Click to proceed.(3)The difference of biofilm formation ability between parent strain and fluoride-tolerant strain was observed by laser confocal microscopy,and the effect of fluoride on biofilm formation ability of fluoride-tolerant strain was divided into six time points(6h,12h,18h,24h,36h,48h)experimental observation and statistics were performed.4?The data obtained from the experiment were statistically compared using SPSS 21.0 one-way ANOVA.Results:1?It was observed by crystal violet staining that the biofilm biomass reached a maximum at 24h-36h and was relatively stable.There was no significant difference in biofilm biomass between the parental group and the fluoride-tolerant group(P>0.05).The biomass of the fluoride group was significantly less than the fluoride-resistant group at the six time points(P<0.05).2?Scanning electron microscopy showed that the morphology of biofilms was prolonged with time.The biofilm structure of the parental group and the fluoride-tolerant group was gradually complicated,and no significant difference was observed.The complete biofilm formation was not observed in the fluorine-containing group during the experimental time.3?The confocal microscope was used to observe the biofilm formation ability.The experimental bioassay showed that the biofilms in the three groups were green fluorescence at 6h-24h,mainly viable.The biofilm at 36h-48h showed yellow fluorescence.The main bacteria.The bacterial density and viable ratio of the parent group and the fluoride-tolerant group were only different at different time points.The bacterial density of the fluorine-containing group was significantly lower than that of the fluoride-resistant group(P<0.01),and the live bacteria ratio was lower at 12h,18h,and 24h.Fluoride-resistant group(P<0.01),the specific mechanism needs further experimental exploration.Conclusion:First,there was no significant difference in the morphology and formation ability of the biofilms of Streptococcus mutans parent strains and fluoride-resistant strains.Second,fluoride significantly inhibited the formation of biofilms of fluoride-resistant strains.