罗伊乳杆菌对致龋变形链球菌拮抗作用的研究

目的研究罗伊乳杆菌对变形链球菌的拮抗作用,初步了解产生拮抗作用的原因。方法利用罗伊乳杆菌无菌上清液,应用双层平板打孔法测定其抑菌效果,再通过滤纸片抑菌法对罗伊乳杆菌发酵的酸乳制品与普通酸乳制品对变形链球菌的抑菌作用进行比较,用饱和硫酸铵沉淀法分析产生拮抗作用的原因。结果罗伊乳杆菌有显著抑菌活性（P〈0.05）,仅罗伊乳杆菌的发酵乳样品对变性链球菌产生直径为6.3mm抑菌圈,80%饱和硫酸铵沉淀的细菌素抑菌活力最强,蛋白酶K处理后无明显抑菌圈。结论本研究证明了罗伊乳杆菌的代谢产物以及罗伊乳杆菌发酵的酸奶制品对致龋菌变形链球菌有着明显的拮抗作用。

The antagonistic effect of Lactobacillus reuteri against one of the major cariogenic organism Streptococcus mutants

Objective To study the antagonistic effect of Lactobacillus reuteri against one of the major cariogenic organism Streptococcus mutants and find the cause of its antagonism. Methods The antagonistic effect of cell-free superna- tants（CFSs） of Lactobacillus reuteri culture was assayed by bilayer plate punch method. And the antagonistic effect of yo- ghurt products containing L. reuteri and common yoghurt against Streptococcus mutants was compared by filter paper bacterio- stasis assay. Finally,the cause of antagonistic effect of Lactobacillus reuteri against Streptococcus mutants was analyzed by saturated ammonium sulfate precipitation assay. Results l-actobacillus reuteri showed a significant growth inhibitory effect against S. mutans, moreover,only the yoghurts containing L. reuteri showed antagonistic effect against Streptococcus mutants and the diameter of inhibition zone was 6.3 mm. The antagonism of bacteriocin precipitated by 80% ammonium sulfate was the strongest,and after the treatment of proteinase K, no significant inhibition zone was found. Conclusion The metabo- lism of Lactobacillus reuteri and yoghurt products fermented by Lactobacillus reuteri both had significant antagonistic effect against S. mutans.