Expression and Identification of Porcine β-Defensin 1 in Escherichia coli and Up-Regulation by Streptococcus Infection in Porcine Tongue In Vivo
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Defensins are members of a major family of antimicrobial peptides that play an important role in the innate immune response, which are of interest as potential novel pharmaceutical agents. We successfully constructed expression system of porcine β-defensin 1 (pBD-1) with his-tag in Escherichia coli Rossetta (DE3) cells and investigated the effect of Streptococcus ATCC 19714 infection on the mRNA expression of pBD-1 in porcine tongue in vivo. The results showed that active pBD-1 not to be affected by the presence of his-tag was obtained and displayed a high antimicrobial activity against Streptococcus ATCC 19714 at a concentration of 42 ± 5.2 μg/ml. The mRNA level of pBD-1 after infection in the tongue mucosa was initially changed with significant up-regulation at 3 h and reached the highest level at 6 h (about tenfold higher than 0 h), thereafter reduced to normal level at 12 h. The results indicated that pBD-1 is shown as a potent antimicrobial activity, and the expression level of pBD-1 against Streptococcus ATCC 19714 is up-regulation in the porcine tongue.
KeywordsPorcine β-defensin 1 Antimicrobial peptides Fusion protein Innate immunity Streptococcus Escherichia coli
This study was supported by Postdoctoral Settled Foundation of Heilongjiang (LBH-Q07017) and Special Foundation for Technological Innovation Research of Harbin (RC2008XK002019). The authors thank the members in the veterinary internal medicine laboratory in the College of Veterinary Medicine, Northeast Agricultural University for their help in collecting the porcine tongue mucosa samples.
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