In this study,the in vitro antimicrobial and antiviral activities of the lysozyme from marine strain S-12-86 (LS) were investigated. The antimicrobial activity of LS was tested by minimum inhibition concentration (MIC) and minimum bactericidal concentration (MBC) method. The inhibiting effects of LS on pseudo rabies virus (PRV) in swine kidney cells (PK-15 cells) were judged by cytopathogenic effect test (CPE). The results showed LS had a broad antimicrobial spectrum against several standard strains including gram-positive bacteria,gram-negative bacteria,fungi,etc. The MIC of LS was 0.25-4.00 mg mL-1 and its MBC was 0.25-8.00 mg mL-1,respectively. Observation under the transmission electron microscope revealed that the cell wall of Candida albicans was distorted seriously,and the cytoplasm with many cavities was asymmetrical after being hydrolyzed by LS. The median cytotoxicity concentration (TC50) of LS was 100.0 μg mL-1,the median effective concentration (EC50) was 0.46 μg mL-1,and the selectivity index (TI = TC50/EC50) was 217. LS could inhibit PRV in PK-15 cells when it was added to cell culture medium at 0,2,4,6,and 8 h after PK-15 cells had been infected by PRV. From the results,we concluded that LS had broad antimicrobial spectrum and good inhibiting effects on PRV.
