[Effects of glycyrrhizic acid on the growth and acid-producing of Streptococcus mutans in vitro].

Objective: To investigate the antibacterial activity of glycyrrhizic acid against Streptococcus mutans (S. mutans, ATCC 25175) in vitro.

Methods: The minimal inhibitory concentration (MIC) and the minimal bactericidal concentration (MBC) of glycyrrhizic acid against S.

[Effect of decoction of Radix glycyrrhizae on the growth and acid-production of Streptococcus mutans in vitro].

Objective: To investigate the antibacterial activity of decoction of Radix glycyrrhizae against Streptococcus mutans (S. mutans) in vitro.

Methods: The decoction of Radix glycyrrhizae was prepared by boiling particles of Radix glycyrrhizae, the diameter was 0.

[Study on protein extraction methods for Streptococcus mutans].

Objective: To establish an efficient and stable method for protein extraction of Streptococcus mutans.

Methods: The collected bacteria were treated by freeze-thaw and ultrasonic (method 1), ultrasonic (method 2), boiling (method 3), boiling and ultrasonic (method 4), respectively. The index such as state of bacteria broken, concentration of extracted protein and SDS-PAGE of protein were employed to evaluate the effects of above four methods.