Influence of bacterial cell concentration and inorganic anions on lysis of Streptococcus mutans BHT by salivary lysozyme.

The aim of this work was to study the influence of bacterial cell concentrations and inorganic anions on lysis of Streptococcus mutans BHT by human salivary lysozyme (HSL). HSL was partly purified from saliva by ion exchange chromatography. The bacteria were grown in a synthetic medium containing 3H-thymidine to monitor DNA release. The experiments demonstrated that release of 3H-thymidine was dependent on the bacterial cell concentration and an apparent Km-value corresponding to approximately 2.9 X 10(8) cells/ml was calculated. The influence of I-, Br-, Cl-, F-, HCO3- and SCN- on bacteriolysis was studied. All anions tested were slightly inhibitory on the action of HSL. The inhibition varied from 7 to 76% depending on the ion and ionic strength. The order of addition of HSL and sodium chloride caused different lytic responses. This was reflected by the amount of HSL adsorbed by the bacteria.