EFFECTS OF PH ON EXPRESSION OF SODIUM-FLUORIDE RESISTANCE IN STREPTOCOCCUS-MUTANS
EFFECTS OF PH ON EXPRESSION OF SODIUM-FLUORIDE RESISTANCE IN STREPTOCOCCUS-MUTANS
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DOI：
10.1177/00220345870660101701
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发表时间：
1987-10-01
影响因子：
7.6
通讯作者：
KRAL, TA
中科院分区：
文献类型：
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作者：
BRUSSOCK, SM;KRAL, TA
采用逐步筛选法，在Todd-Hewitt琼脂上筛选出变异链球菌GS-5耐氟突变株。抗性在此定义为在48小时内形成集落的能力。第一步突变体表现出六种不同水平的抗性，范围为400至1000 μ g/mL氟化钠。第二步突变体表现出两种水平的抗性，一种在1600 μ g/mL氟化钠下，最高在3000 μ g/mL氟化钠下。在pH 5和6下测试所有突变体（最初在pH 7.2下分离）的氟化物抗性。在这些较低的pH值，所有的突变体表现出耐氟与亲本菌株相比，但在大大降低的水平。
Stable fluoride-resistant mutants of Streptococcus mutans GS-5 were isolated on Todd-Hewitt agar by a step-wise selection procedure. Resistance is defined here as the ability to form colonies in 48 hr. First-step mutants demonstrated six different levels of resistance, ranging from 400 to 1000 .mu.g/mL sodium fluoride. Second-step mutants demonstrated two levels of resistance, one at 1600 and the highest at 3000 .mu.g/mL sodium fluoride. All mutants (originally isolated at pH 7.2) were tested for fluoride resistance at pH 5 and 6. At these lower pH values, all of the mutants demonstrated resistance to fluoride when compared with the parent strain, but at much-reduced levels.