Abstract:

Objective  This study aimed to detect the difference in the expression levels of autolysin atlS gene of Streptococcus gordonii (S. gordonii) at different growth stages and pH values, as well as to analyze the factors regulating atlS gene expression in S. gordonii. Methods  S. gordonii wild strains (ATCC 35105) were collected at different growth stages (early exponential phase, mid-exponential phase, late exponential stage, and platform stage) and pH values (pH 7 and pH 5.5), and total RNA was extracted by using a conventional method. Fluorescence quantitative polymerase chain reaction (FQ-PCR) was used to measure the relative mRNA expression of atlS gene, with bacterial 16S rRNA as internal reference, for a comparison of the mRNA levels of atlS gene expression in S. gordonii at different growth stages and pH values. Results  FQ-PCR results showed that atlS gene expression increased with gradually increasing growth stage under neutral conditions and was higher than that under acidic conditions (P<0.05). Conclusion  The atlS gene expression in S. gordonii is influenced by growth stage and pH value factors.

Key words:  Streptococcus gordonii, atlS gene, fluorescence quantitative polymerase chain reaction