title: Probiotic Lactobacillus casei expressing porcine antimicrobial peptide PR39 elevates antibacterial activity in the gastrointestinal tract.
abstract: PR39, a 4.7 kDa proline-rich antimicrobial peptide, acts as a cationic host defense peptide. In addition to killing bacteria, PR39 mediates inflammatory reactions, including cell proliferation, migration, wound healing, and angiogenesis. Here, we examined the antibacterial effects of this peptide. The synthetic gene fragment PR39 was inserted into the secretory expression vector plasmid pPG:612 of Lactobacillus casei, yielding the recombinant strain pPG:612-PR39/L. casei 393. In vitro antibacterial tests showed that expression of the PR39 peptide in recombinant L. casei resulted in antibacterial activity against Escherichia coli and Salmonella but had only minor antibacterial effects in Staphylococcus aureus. In addition, BALB/c mice fed the recombinant pPG:612-PR39/L. casei 393 grew better and had increased peripheral blood lymphocyte percentages, white blood cell numbers, and spleen indices than mice in the control group. Scanning electron microscopy showed that jejunum and duodenum villus height, crypt depth, and the ratio of villus height/crypt depth in the intestinal villi also increased. Moreover, mice fed the recombinant strain showed significantly lower mortality rates than the control group mice when challenged with the enterotoxigenic E. coli K88+. Thus, this recombinant expression system had the beneficial characteristics of both L. casei and PR39, supporting its potential as an animal feed additive.
authors.affiliation: College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.|College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.affiliation: College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.|College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.
authors.forename: Dian
authors.initials: D
authors.lastname: Guo
authors.affiliation: College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.|College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.
authors.forename: Yangxin
authors.initials: Y
authors.lastname: Liu
authors.affiliation: College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.|College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.
authors.forename: Yilan
authors.initials: Y
authors.lastname: Shao
authors.affiliation: College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.|College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.
authors.forename: Yufeng
authors.initials: Y
authors.lastname: Wang
authors.affiliation: College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.|College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.
authors.forename: Yigang
authors.initials: Y
authors.lastname: Xu
authors.affiliation: College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.|College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.
authors.forename: Yanping
authors.initials: Y
authors.lastname: Jiang
authors.affiliation: College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.|College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.
authors.forename: Wen
authors.initials: W
authors.lastname: Cui
authors.affiliation: College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.|College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.
authors.forename: Yijing
authors.initials: Y
authors.lastname: Li
authors.affiliation: College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.|College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.
authors.forename: Lijie
authors.initials: L
authors.lastname: Tang
keywords: Lactobacillus casei; activité antimicrobienne; antimicrobial activity; antimicrobial peptide PR39; expression recombinante; peptide antimicrobien PR39; recombinant expression