【摘要】 目的:了解不同致龋力的变异链球菌临床分离株(593号高致龋力临床株和18号低致龋力临床株)在生物膜状态不同时间段合成胞外多糖的能力差异。方法:①在聚苯乙烯塑料片上分别形成3、12、20 h变异链球菌生物膜标本,用异硫氰酸荧光素标记的伴刀豆球蛋白A对其中的胞外多糖进行染色,激光共聚焦扫描显微镜观察。②采用静置法培养形成粘附生长的细菌,蒽酮法测定3～24 h其合成胞外多糖的量。结果:①胞外多糖与染料结合后发出绿色荧光,各时间段593号临床株绿色荧光的分布较18号临床株更致密和广泛。②3～20 h 593号临床株合成水溶性葡聚糖能力强于18号临床株(P<0.05);3～16 h 593号临床株合成水不溶性葡聚糖能力强于18号临床株(P<0.05);其他时间点二者合成胞外多糖的能力无显著性差异(P>0.05)。结论:在生物膜形成过程中两菌株合成胞外多糖量随时间延长而增加,593号临床株在生物膜形成早期3～16 h更强的合成胞外多糖能力(含水溶性和水不溶性葡聚糖),可能是其具高致龋力的原因之一。更多还原

【Abstract】 Objective: To observe the exopolysaccharides produced by biofilm cells of clinical strains 593 and 18 and the difference between the two strains.Methods:① Streptococcus mutans biofilms formed on polystyrene plastic sheets in 3,12 and 20 hours respectively,exopolysaccharides distribution,after fluorescein isothiocyanate-conjugated concanavalin A staining,were visualized by confocal scanning laser microscopy.② The amounts of exopolysaccharides by adhesive streptococcus mutans in different culture time were determined by the anthrone method.Results: After combining with the fluorescent stain,the exopolysaccharides showed green light.Strain 593 in biofilm possessed stronger ability to synthesize exopolysaccharides than strain 18,especially the amount of water soluble glucans in 3～20 h and water insoluble glucans in 3～16 h(P<0.05).Conclusion: The stronger ability of biofilm strain 593 to synthesize exopolysaccharides in the early biofilm formation stage during the 3～16 h may be the reason for its higher cariogenic ability.更多还原