中文摘要：

目的：利用变异链球菌luxS基因敲除的突变株,研究该基因缺陷对于生物膜多糖基质的影响。方法：通过向生物膜培养悬液中加入与细菌直径相近的磁性小珠,利用这些小珠由于生物膜约束而在磁场中位移受限的原理,采用生物膜定量分析仪,定量比较luxS突变株与野生株在利用外源性碳水化合物合成生物膜多糖基质能力方面的差异。采用SPSS 10.0软件包对实验数据,进行Dunnet双侧t检验。结果：变异链球菌luxS基因突变株与野生株均可利用碳水化合物合成胞外多糖基质,且外源性糖的加入可显著促进生物膜的形成。在加入1%蔗糖时,2菌株生物膜均在1h内迅速形成,而两者之间无显著差异。在加入1%葡萄糖时,两菌株的生物膜形成速度均有所加快,突变株的改变则更为明显。结论：luxS基因参与调节细菌对多糖基质代谢的过程,而其对于生物膜形成的影响也更多是通过调节多糖基质代谢实现的。

英文摘要：

PURPOSE： To investigate the effect of Streptococcus mutans luxS gene on polysaccharide matrix metabolism.METHODS： Based on the immobilization of magnetic beads by adherent cells,an assay of biofilm quantitative analysis was developed for the kinetic quantification of biofilm formation.S.mutans luxS gene mutant strain and wild-type strain were compared for their ability of utilizing exogenous carbohydrate to form extracellular polysaccharide matrix.SPSS 10.0 software package was used for statistical analysis.Dunnet t two-side test of one factor analysis of variance was performed.RESULTS： Both luxS mutant strain and wild-type strain could use exogenous carbohydrate to form polysaccharide matrix.With 1% sucrose added,both strains completed their biofilm formation within one hour.When adding 1% glucose,these strains also accelerated the formation of biofilm,and this was more significant in the mutant strain.CONCLUSIONS： The luxS gene of S.mutans can regulate its extracellular polysaccharide matrix metabolism.Moreover,the regulation of this gene on biofilm formation is more probably via polysaccharide matrix pathway.