Antimicrobial activity of yak beta-defensin 116 against Staphylococcus aureus and its role in gut homeostasis

Staphylococcus aureus (S. aureus) is one of the most common food-borne poisoning microbial agent. However, the antimicrobial activity of beta-defensin 116 in yak and its application in S. aureus-induced diarrheal disease have not been reported. In this study, 303 bp cDNA sequence of yak DEFB116 gene was obtained. In addition, the prokaryotic expression vector of DEFB116 protein with a molecular weight of 16 kDa was successfully constructed and expressed. The yak DEFB116 gene can encode 19 amino acids, the percentage of hydrophobic amino acids is 36 % and the total positive charge is 6, which has potential antibacterial potential. Sufficient DEFB116 protein concentration and time can destroy the integrity of the bacterial cell membrane, resulting in leakage of intracellular solutes and thus killing S. aureus. The intestinal histopathological features and the number of inflammatory cells were improved in the diarrhea mouse model under the action of DEFB116 protein. The decrease of goblet cells was reversed, the expression of mucoprotein was increased. DEFB116 protein increased the abundance of Lactobacillus johnsonii, Lactobacillus reuteri and Desulfovibrio, and inhibited the reproduction of pathogenic bacteria. These findings provide new insights into the potential future applications of yak beta-defencins in the food industry and medical fields.

Automated summary

This study reports the antimicrobial activity of yak beta-defensin 116 against Staphylococcus aureus and its application in diarrheal disease. The findings suggest that DEFB116 protein can disrupt bacterial cell membrane, kill S. aureus, and improve histopathological features in a mouse model of diarrhea. Additionally, DEFB116 protein increases the abundance of beneficial bacteria and inhibits the growth of pathogenic bacteria.