Characterization and Antimicrobial Efficacy of Bovine Dermcidin-Like Antimicrobial Peptide Gene ‎

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Due to the significance of the antimicrobial peptides as innate immune effectors, in this study, a novel bovine antimicrobial peptide and its antimicrobial spectrum were described. RNA isolation from various tissues and RT-PCR were conducted. The DCD-like peptide was synthesized, and its antimicrobial effect was analyzed. The bovine dermcidin-like gene contains 5 exons intermittent by 4 introns. Bovine DCD-like mRNA was 398 bp with ORF size of 336 bp. Bovine DCD-like was expressed in skin and blood. Analysis of amino acid compositions showed that cysteine was repeated six times, which indicates the presence of 3 disulfide bonds that play a role in the peptide stability. Bovine DCD-like had an antimicrobial effect on Enterococcus faecalis, Streptococcus bovis, and  Staphylococcus epidermidis, which was highest at 50 and 100 µg/ml. The effect on Candida albicans and Escherichia coli was slightly low. In Staphylococcus aureus, the activity of bovine DCD-like was affected greatly at pH 4.5 and 5.5. The optimum salt concentrations were 50 and 100 mM with E. coli and all other bacterial strains, respectively. In C. albicans, the activity of bovine DCD-like decreased with increasing pH regardless of the concentration of NaCl. The pH 6.5 of the sweat buffer was optimum for the activity of bovine DCD-like. Finally, it was concluded that the bovine DCD-like gene expressed in skin cells and the DCD-like peptide secreted into the sweat, had high antimicrobial activities against many Gram-positive and -negative strains, as well as yeast-like fungus.