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目的 :分析ffh基因沉默对变形链球菌耐氟菌株体外耐酸能力的影响。方法 :利用电穿孔法,将si RNA转入UA159-FR,使其与ffh基因靶向位点结合,筛选出含ffh基因沉默的变形链球菌耐氟菌株,与UA159-FR的标准菌液分别在不同p H值(以0.5为间隔,p H为3.5~7.5)的BHI液体培养基中37℃微需氧(95%N2、5%CO2)培养24 h,离心,采用p H计测定培养物上清的终末p H值;5 m L生理盐水稀释细菌沉淀,用紫外分光光度计测定600 nm处的吸光度,采用SPSS 17.0软件包对所得数据进行统计学分析。结果:原菌株UA159-FR与ffh基因沉默的变形链球菌UA159-FR相比,Δp H差异显著(P<0.05),且前者高于后者。两者比较p H=3.5~5.0时,OD600有显著差异(P<0.01);p H=5.5~7.5时,OD600有显著差异(P<0.05),且两者生长趋势相似。结论:ffh基因沉默对变形链球菌耐氟菌株的耐酸性有一定影响。
Objective: To analyze the effect of ffh gene silencing on acid-fast tolerance of Streptococcus mutans-resistant strains in vitro. METHODS: The si RNAs were transferred into UA159-FR by electroporation and combined with the target site of ffh gene. The fluoride-resistant strains of Streptococcus mutans that contained ffh gene silencing were screened and compared with the standard strains of UA159-FR The cells were cultured in BHI broth with different p H values (p 0.55 to 7.5 at 0.5 intervals) for 24 h at 37 ° C in microaerobic oxygen (95% N 2, 5% CO 2), centrifuged and assayed by p H The final p H value of the supernatant was measured. The bacterial pellet was diluted with 5 mL normal saline and the absorbance at 600 nm was measured by UV spectrophotometer. The data were analyzed by SPSS 17.0 software package. Results: The original strain UA159-FR had a significant difference in Δp H (P <0.05) compared with UF-Sf mutants silenced by ffh gene, and the former was higher than the latter. There was a significant difference in OD600 between p5 = 5.0 and 5.0 (P <0.01). There was a significant difference in OD600 between p5 = 7.5 and 7.5 (P <0.05). Conclusion: ffh gene silencing has some effect on the acid resistance of Streptococcus mutans-resistant strains.