不同蔗糖浓度下外源性右旋糖酐酶与氟化钠对粘放线菌生物膜的影响

The influence of exogenous dextranase and sodium fluoride on biofilm of Actinomyces viscosus under different sucrose concentration conditions

目的探索在不同蔗糖浓度条件下,外源性右旋糖酐酶(Dex)与氟化钠(NaF)对粘放线菌生物膜的影响。方法利用结晶紫染色法测定粘放线菌生物膜量。用二甲氧唑黄(XTT)法检测细菌生物膜的活性。用pH仪测定细菌培养初始液体培养基的pH值(pH1)及培养18h后培养基的pH值(pH2),并计算ΔpH(pH1-pH2)。结果在不同蔗糖浓度条件下,各组细菌生物膜量先随蔗糖浓度升高而增加,至蔗糖质量分数为0.5%时到达峰值,继而随浓度升高生物膜量减少;在蔗糖质量分数为1%时,Dex+NaF组生物膜量明显小于Dex组或NaF组。随着蔗糖浓度的增加,各组生物膜活性有降低趋势。相同蔗糖浓度下,Dex组生物膜活性与对照组相似(P>0.05);NaF组生物膜活性较之对照组有轻度增加(P<0.05)。随着蔗糖浓度增加,各组ΔpH变化趋势为先增大后减小;在蔗糖质量分数为0.25%~2%时,Dex和NaF单独使用及联合使用时均能抑制细菌产酸。结论在本实验条件下,Dex和NaF对细菌生物膜的形成、生物膜活性及细菌产酸的作用受蔗糖浓度的影响。在蔗糖质量分数为1%时,Dex和NaF联用对粘放线菌生物膜形成的抑制作用表现出协同作用。在蔗糖质量分数为2%时,Dex和NaF能协同抑制细菌生物膜产酸。

Objective To explore the impact of exogenous dextranase（Dex） and sodium fluoride（NaF） on the biomass, biofilm vitality and acid production ofActinomyces viscosus in different sucrose concentration substrate. Methods Crystal violet staining was used to quantify the biomass ofA. viscosus in each group. 2,3 bis（2 methoxy 4 nitro 5 sulfophenyl） 5 [（phenylamino）carbonyl] 2H tetrazolium hydroxide（XTT） assay was used to detect the vitality of the bacterial biofilms, pH electrode was applied to measure the pH values of the initial（pHI） and the 18 h liquid culture medium（pH2）, and then the ApH（pHI-pH2） values was calculated. Results Under different sucrose concentration conditions, the bacterial biomass increased with the increase of sucrose concentration, and reached the peak at a sucrose mass fraction of 0.5%, and then decreased with the increase of sucrose concentration. In the 1% sucrose mass fraction groups, the bacterial biomass formed in the Dex＋NaF group was significantly less than in the Dex or NaF group. In all groups, the bacterial vitality was decreased along with the increased sucrose concentration. Under the same sucrose concentration, the bacteria vitality of the Dex group was similar to that of the control group（P〉0.05）, and there was a slight increase in the bacteria vitality in the NaF group compared with the control group（P〈0.05）. With the increase of sucrose concentration, ApH changes were first increased and then decreased. The single or combined use of NaF and Dex could inhibit the acid production of A. viscosus under the sucrose mass fraction ranged from 0.25% to 2%. Conclusion Sucrose concentration was one of the factors that can influence the effect of Dex and NaF, both single and combination, on the bacterial biomass, biofilm vitality and acid production. The inhibitory effect of the combined use of Dex and NaF on the formation of bacterial biofilm showed a synergistic effect at the sucrose mass fraction of 1%. Dex and NaF displayed synergistic effect on acid production at the sucrose mass fraction of 2%.