[ Objective] The aim of the research was to select alkaline pmtease-producing strains and provide basis for the application in production. [ Method ] An alkaline protease-preducing strain was isolated from the sea wat...[ Objective] The aim of the research was to select alkaline pmtease-producing strains and provide basis for the application in production. [ Method ] An alkaline protease-preducing strain was isolated from the sea water and sea mud collected from Qingdao coastal area. After ultraviolet mutagenesis and microwave mutagenesis, a target strain ZR-58-3-1-3 was obtained. The protease activity and enzymatic properties of the strain were determined preliminarily. [ Result ] Prote- ase activity of the selected strain reached 145 U/ml. After the compound mutagenesis, protease activity of the fermentation liquid of strain ZR-58-3-1-3 reached 775 U/m｜, which was about 4.3 times higher than that of the original strain. The optimal temperature for alkaline protease produced by strain ZR-58-3-1-3 was 45℃, and the optimal pH was 8.5, suggesting it belongs to moderate temperature protease with relatively high thermal stabihty. [ Conclusion] Strain ZR-58-3-1-3 has stable alkaline protease production performance and can be used as an alkaline protease-producing mutant strain.展开更多
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 ...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 ceils） 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,展开更多
文摘[ Objective] The aim of the research was to select alkaline pmtease-producing strains and provide basis for the application in production. [ Method ] An alkaline protease-preducing strain was isolated from the sea water and sea mud collected from Qingdao coastal area. After ultraviolet mutagenesis and microwave mutagenesis, a target strain ZR-58-3-1-3 was obtained. The protease activity and enzymatic properties of the strain were determined preliminarily. [ Result ] Prote- ase activity of the selected strain reached 145 U/ml. After the compound mutagenesis, protease activity of the fermentation liquid of strain ZR-58-3-1-3 reached 775 U/m｜, which was about 4.3 times higher than that of the original strain. The optimal temperature for alkaline protease produced by strain ZR-58-3-1-3 was 45℃, and the optimal pH was 8.5, suggesting it belongs to moderate temperature protease with relatively high thermal stabihty. [ Conclusion] Strain ZR-58-3-1-3 has stable alkaline protease production performance and can be used as an alkaline protease-producing mutant strain.
文摘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 ceils） 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,
