变异链球菌的htrA和clpP基因对其生长和饥饿耐受的影响  

The influence of htrA and clpP gene on starvation tolerance and growth characteristics of Streptococcus mutans

作　　者：王拓[1] 于丹妮[1] 季晓黎[1] 任志明[1] 李娜[2] 韩育植[2] 

机构地区：[1]天津医科大学第二附属医院,天津300211 [2]天津医科大学研究生学院,2009级天津300070

出　　处：《牙体牙髓牙周病学杂志》2011年第10期573-576,共4页Chinese Journal of Conservative Dentistry

摘　　要：目的:观察变异链球菌(下称变链菌)htrA-clpP双基因缺陷株的生长特点;比较缺陷株与标准株在饥饿条件下生长情况的差异。方法:将两菌株分别培养在含有10 g/L葡萄糖及无碳源的TPY培养基中,37℃微需氧条件下培养,从接种入培养基开始以2 h为间隔采用酶联免疫检测仪在600 nm下测定各菌株在两种生长条件下的生长曲线并比较其生长情况的差异,同时在各时间点使用葡萄糖氧化酶法试剂盒测定在含葡萄糖培养基中生长的两菌株耗糖情况并比较其差异。结果:①缺陷株在含10 g/L葡萄糖和无碳源TPY培养基中生长时,生长周期都发生了改变,对数期峰值提前且此阶段生长速度较标准株快(P<0.05),而标准株的对数期峰值及平台期A值均明显高于缺陷株(P<0.05);②标准株和缺陷株在无碳源条件下生长时细胞的生长能力较葡萄糖条件下明显降低(P<0.05);③缺陷株消耗葡萄糖的速度较标准株快(P<0.05)。结论:htrA和clpP基因缺陷可在一定程度上导致变链菌的生长及抗饥饿能力降低。AIM： To observe the growth characteristics of the htrA-clpP mutant strain of Streptococcus mutans and to compare the growth difference of the standard strain and the mutant strain under starvation.METHODS： Standard Streptococcus mutans strain and the mutant strain were cultured respectively in TPY medium containing 10g/L of glucose or TPY containing no carbohydrate,under anaerobic condition at 37 ℃.The growth curve of each strain was determined by Thermo Labsystems.Consumption of glucose of the two strains was examined by glucose oxidase method.RESULTS： ① Growth cycle of the mutant strain changed in TPY medium containing glucose or TPY containing no carbohydrate.The exponential phase shortened and the mutant strain grew faster than the standard strain（P〈0.05）.However,the standard strain grew faster than the mutant strain during the stationary phase（P〈0.05）.② Both strains grew slower in TPY with no carbohydrate（P〈0.05）.③ The mutant strain consumed more glucose than the standard strain.CONCLUSION： Defect of htrA and clpP gene can reduce the capacity of Streptococcus mutans to grow and to resist starvation.

关 键 词：变异链球菌 htrA—clpP双基因缺陷株 HtrA蛋白酶 ClpP蛋白酶 生长 饥饿耐受 

分 类 号：R780.2[医药卫生—口腔医学]