单核细胞增生李斯特菌噬菌体裂解酶Lys039的活性分析及初步应用OA北大核心CSTPCD

To investigate the properties of Listeria monocytogenes phage endolysin and initial application in food matrix,the gene sequence of Listeria bacteriophage endolysin Lys039 was obtained from NCBI and subjected to bioinformatics analysis.The gene was then expressed and purified in E.coli,and its lytic activity,influence on biofilm,and application in milk matrix were investigated.The results showed that:1)Lys039 was composed of 341 amino acids,with a molecular weight of 36.4 ku and isoelectric point of 9.81.Its structure exhibited amidase activity and lyses the cell walls of 22 strains of Listeria monocytogenes,2 strains of Listeria innocua,1 strain of Listeria ivanovii,and 1 strain of Listeria welshimeri in our laboratory.However,it exhibit no lytic activity on Staphylococci spp,Bacillus subtilis,and Salmonella spp.2)The lytic activity of Lys039 increased gradually with concentration enrichment,the optimum temperature was 30 ℃and the optimal pH value was 6.0.3)Lys039 can effectively clear the biofilm formed by Listeria monocytogenes and reduce the number of Listeria monocytogenes in milk.In conclution,Lys039 has a wide range of temperature tolerance,acid and alkali resistance and wide lytic spectrum,which can significantly reduce biofilm and has good preliminary application.This study provides a theoretical basis for further prevention and rapid detection of Listeria monocytogenes.