LuxS基因缺失对变形链球菌耐酸性的影响  

Effects of LuxS gene deletion on the acid resistance ability of Streptococcus mutans

作　　者：于丹妮[1] 陈杰[1] 张耀超[1] 韩育植[1] 

机构地区：[1]天津医科大学第二医院口腔科,300211

出　　处：《实用口腔医学杂志》2009年第6期838-841,共4页Journal of Practical Stomatology

基　　金：天津市自然科学基金资助项目(编号:06YFJMJC06900)

摘　　要：目的:探讨变形链球菌Ingbritt C(血清C型)国际标准株与LuxS基因缺失的变形链球菌突变株之间耐酸能力的差异。方法:配制相同浓度的变形链球菌标准株与LuxS缺陷株菌悬液,分别在不同pH值(pH3.5～7.0)的BHI液体培养基中培养相同时间后,用紫外分光光度计测定吸光度,比较2种菌株的生长情况;先在轻度酸性环境(pH5.5)中预酸化,再将2种菌株于致死性pH值环境(pH3.0)中培养,比较其适应性耐酸能力。结果:①pH值为6.0～7.0时,2种菌珠在相同pH值条件下生长情况间的差异无显著性(P>0.05),且3组不同pH值条件下细菌生长情况间的差异亦无显著性(P>0.05);②pH值为4.5～5.5时,2种菌株的生长情况的差异有显著性(P<0.05);③在pH值为3.0时,LuxS缺陷株的生存率(0.006 5%)要明显低于标准株的生存率(0.078%),差异有显著性(P<0.05)。④在pH值5.5环境下预酸化后,LuxS缺陷株的生存率(0.747%)约为标准株生存率(8.65%)的1/10。结论:在亚致死性pH值中,变形链球菌标准株与LuxS缺陷株的耐酸能力具有差异,标准株的耐酸能力强于LuxS缺陷株,2种菌株均表现出了适应性耐酸的能力;变形链球菌LuxS缺陷株对酸的敏感性增加,而适应性耐酸能力仍然存在。Objective： To study the difference between the acid resistance of Streptococcus mutans Ingbritt C international standard strain and the acid resistance of LuxS mutant strain. Methods： Solutions of Streptococcus mutans standard strain and LuxS mutant strain with same density were prepared and cultured at pH 3.5 to 7.0 BHI liquid for same period. Terminal growth situation was compared. After being acidized in pH 5.5 BHI liquid, the two strains were cultured at pH 3.0 BHI liquid. The acid tolerance responses of the two strains were compared. Results： （1）At pH 6.0 to 7.0, the difference of growth between Streptococcus mutans standard strain and LuxS mutant strain was not significant at the same pH value, and the differences of bacterial growth situation under three different pH values were not significant. （2）At pH 4.5 to 5.5, the difference of growth between the two strains was significant. （3）At pH 3.0,the survival rate of LuxS mutant strain（0. 006 5% ）was significantly lower than the standard strain （0.078%）. （4）At pH 5.5, the survival rate of LuxS mutant strain（0. 747% ）was lower than the standard strain（8.65% ）by about 10 times after the pre-acidification. Conclusion： At sub-lethal pH value, there is significant difference of aciduricity between Streptococcus mutarts standard strain and LuxS mutant strain. The acid resistance of standard strain is stronger than that of LuxS mutant strain. The two strains both display the capability of acid tolerance responses. LuxS mutant strain is more sensitive to acid inactivation, but the capability of acid tolerance responses still exists.

关 键 词：变形链球菌 LUXS基因 耐酸性 突变株 

分 类 号：R780.2[医药卫生—口腔医学]