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目的观察模拟失重对变异链球菌生长、产酸及合成胞外多糖的影响,探讨模拟失重环境下变异链球菌的生物学效应。方法采用高截面纵横比容器(high aspect ratio vessel,HARV)建立模拟失重细菌培养模型,将变异链球菌分为正常对照组、模拟失重组,在2、4、6、8、10、12、16、20和24 h,比较其菌液的OD600nm吸光度值并绘制生长曲线;培养24 h后,测定p H值并分析p H变化;通过蒽酮法分析模拟失重对细菌合成水不溶性及水溶性胞外多糖的影响。结果与对照组相比,模拟失重组变异链球菌提前进入对数生长期,2、4、6、8、10、12 h的OD600nm值升高(P<0.05);16、20、24 h的OD600nm值无明显变化(P>0.05)。模拟失重条件下变异链球菌的产酸能力与对照组相比差异无统计学意义(P>0.05),合成水不溶性及水溶性胞外多糖的能力较对照组有明显抑制(P<0.05)。结论短期失重环境对变异链球菌生长及合成胞外多糖的能力有一定影响,其作用机理有待深入研究。
Objective To observe the effects of simulated weightlessness on the growth, acid production and extracellular polysaccharide of Streptococcus mutans, and to explore the biological effects of Streptococcus mutans in a simulated weightlessness environment. Methods The model of simulated weightless bacteria culture was established by using high aspect ratio vessel (HARV). The Streptococcus mutans were divided into normal control group and simulated weightlessness group. At 2,4,6,8,10,12,16 , 20 and 24 h respectively. The OD600nm absorbance value of the bacteria solution was compared and the growth curve was drawn. After cultured for 24 h, the p H value was determined and the changes of p H were analyzed. Anthrone method was used to simulate the water insoluble and water-soluble cells Exopolysaccharide effects. Results Compared with the control group, the streptococcus mutans of simulated weightlessness group entered the logarithmic growth phase in advance, and OD600nm increased at 2, 4, 6, 8, 10 and 12 h (P <0.05); at 16, 20 and 24 h OD600nm value no significant change (P> 0.05). Compared with the control group, there was no significant difference in the acidogenic capacity of S. mutans under simulated weightlessness (P> 0.05). The ability of synthesizing water-insoluble and water-soluble exopolysaccharides was significantly inhibited compared with the control group (P <0.05). Conclusion Short-term weightlessness environment has an impact on the growth of Streptococcus mutans and the ability to synthesize exopolysaccharide, and its mechanism needs further study.