luxS基因在变形链球菌生物膜形成中的硫代谢作用

The sulfur metabolism functional of luxS in the Streptococcus mutans for biofilm formation

目的通过比较在不同条件培养基中变形链球菌IngbrittC国际标准株及luxS基因缺陷株24h生物膜形成的厚度及平均荧光强度,探讨luxS基因在变形链球菌生膜形成中的硫代谢作用。方法建立以圆形玻片为载体的生物膜模型,通过营养补充实验培养两菌株生物膜,利用激光共聚焦扫描显微镜观察测定两菌株生物膜厚度和平均荧光强度。结果当分别加入一定浓度半胱氨酸、蛋氨酸时,缺陷株生物膜厚度有明显增长,但未恢复至标准株水平;加入半胱氨酸,标准株生物膜厚度有所增加;当加入S-腺苷甲硫氨酸时,缺陷株与标准株生物膜的厚度均降低。结论在变形链球菌生物膜形成中,luxS基因不但具有密度感应功能,在硫代谢中也起着重要作用。

Objective In order to study the sulfur metabolism role of luxS gene for biofilm formation,we have performed the experiment to compare the biofilm thickness and mean fluorecence intensity of Streptococcus mutans Ingbritt C international standard strain and luxS mutant strain in different kinds of culture medium for 24 h cultivation. Methods The biofilm models of both Streptococcus mutans standard strain and luxS mutant strain were built on the carriers of round slides. The biofilm cultivation of the two strains was carried out by nutritional complementation experiments. Confocal laser scanning microscopy was used to observe and determinate the thickness of biofilm and mean fluorecence intensity. Results A significant increase in the thickness of luxS mutant strain biofilm was observed after the addition of cysteine as well as methionine,but the standard strain levels were not reached; the biofilm thickness of standard strain increased after the addition of cysteine; the biofilm thickness of the both kinds of strains decreased after the addition of SAM. Conclusions Apart from its role in quorum sensing,luxS gene also plays an important part in sulfur metabolism for biofilm formation of Streptococcus mutans.