Biocidal activity of chicken defensin-9 against microbial pathogens

In this study we identified the expression patterns of β-defensin-9 in local chicken from Saudi Arabia, evaluated antimicrobial activities of the synthetic chicken β-defensin-9 (sAvBD-9) against pathogenic bacteria and fungi, and investigated the mode of sAvBD-9 action on the bacterial cells. The AvBD-9 gene of the local Saudi chicken encodes a polypeptide of 67 amino acids, which is highly similar to the duck, quail, and goose polypeptides (97%, 86%, and 87%, respectively) and shares a low sequence similarity with the mammalian defensins. AvBD-9 is expressed in various organs and tissues of the local chicken and is able to inhibit the growth of both Gram-negative and Gram-positive bacteria, as well as is active against unicellular and multicellular fungi, Aspergillus flavus, Aspergillus niger, and Candida albicans. The sAvBD-9 completely inhibited the growth of both Gram-positive and Gram-negative bacterial strains as well as Candida albicans. The haemolytic effects of sAvBD-9 were limited. The morphological analysis by TEM revealed that sAvBD-9 induces shortening and swelling of Staphylococcus aureus and Shigella sonni cells, opens holes and deep craters in their envelopes, and leads to the release of their cytoplasmic content. Our data shed light on the potential applications of sAvBD-9 in the pharmaceutical industry.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author