中国生物工程杂志

To construct a secretary-expression vector of antimicrobial peptide Bactenecin 7 (Bac7), transform it into Lactococcus lactis MG1363, and identify the expression product and its bioactivity. The DNA sequence of Bac7 and its regulation elements was synthesize with overlap-extension PCR. Then the interest gene was cloned into the shuttle-vector pMG36e after it was digested by Sac I and Hind III, the recombination vector was transformed into Lactococcus lactis MG1363 with electrophoration. RT-PCR and Western blot assays were applied to investigate the expressions of the Bac7 gene, and the bioactivity of the expression products Bac7 in culture supernatant was tested with plate-diffusion method. According to the DNA sequencing and double enzyme digestion results, the recombinant vector was successfully constructed and transformed into Lactococcus lactis MG1363, Lactococcus lactis MG1363 carried the recombination vector could secrete bioactive antimicrobial peptide Bac7. All these results indicate the recombination lactic acid bacteria can expression and secrete bioactive Bac7 efficiently, which lay a foundation for further study of oral administration of a Bac7-secreting lactic acid bacteria to treat intestinal bacteria infection.