【摘要】 目的:比较远缘链球菌在游离和黏附状态下合成水溶性、水不溶性多糖的能力并探讨其原因。方法:在不同培养时间和多种蔗糖浓度条件下,对远缘链球菌进行摇动培养和静止培养,以模拟该菌在游离和黏附的状态下生长。采用蒽酮法测定细菌合成的水溶性和水不溶性多糖的含量,实验数据采用SPSS10.0软件包分析,选用单因素方差分析的Dunnett双侧检验比较组间的差异有无统计学意义。结果:生物膜形成发展期,游离菌合成的水溶性多糖随培养时间的延长而增多,黏附菌合成的水溶性多糖则随时间呈下降趋势;在生物膜成熟期,黏附菌合成的水不溶性多糖多于游离菌(P<0.05),而两者合成的水溶性多糖量的差异无显著性(P>0.05)。细菌合成的水溶性、水不溶性多糖随蔗糖浓度的增加而增加;在各个蔗糖浓度条件下,黏附菌合成的水不溶性胞外多糖量显著多于游离菌(P<0.05),而水溶性胞外多糖的量差异不大(P>0.05)。结论:培养时间和蔗糖浓度增加,导致远缘链球菌合成的水不溶性胞外多糖较游离状态明显增加;生物膜特殊的生长环境,是造成这种差异的可能原因。更多还原

【Abstract】 PURPOSE:To elucidate the amount of exopolysaccharides produced by Streptococcus sobrinus when cultivated at different conditions.METHODS:S.sobrinus was grown in TS broth and was allowed to attach to the cover glass surface to form bioflims.The anthrone method was applied to measure the amounts of soluble and insoluble exopolysaccharides produced by attached S.sobrinus and planktonic ones when cultivated at different time and in different concentrations of sucrose.The data were analyzed using SPSS 10.0 software package,Dunnett’s t test was used to compare the difference between the two groups.RESULTS:Attached bacteria synthesized more insoluble polysaccharide than planktonic ones at every sucrose concentration(P<0.05),but almost the same production of soluble polysaccharide(P>0.05).CONCLUSION:The ability of S.sobrinus to synthesize insoluble polysaccharide was enhanced in the adherent phase,which may clarify why bacteria in biofilms are highly cariogenic.更多还原