Antimicrobial activity and mechanism of the human milk-sourced peptide Casein201

• DOI: 10.1016/j.bbrc.2017.02.108
• Publication Date: 2017-02-27T16:30:57Z
• Authors: Fan Zhang; Xianwei Cui; Yanrong Fu; Jun Zhang; Yahui Zhou; Yazhou Sun; Xing Wang; Yun Li; Qianqi Liu; Ting Chen
• Keywords: Staphylococcus aureus; 0303 health sciences; Milk, Human; Infant, Newborn; Caseins; Bacterial Infections; Microbial Sensitivity Tests; Listeria monocytogenes; 3. Good health; Klebsiella pneumoniae; 03 medical and health sciences; Anti-Infective Agents; Microscopy, Electron, Transmission; Escherichia coli; Microscopy, Electron, Scanning; Humans; Female; Amino Acid Sequence; Peptides; Yersinia enterocolitica

Casein201 is one of the human milk sourced peptides that differed significantly in preterm and full-term mothers. This study is designed to demonstrate the biological characteristics, antibacterial activity and mechanisms of Casein201 against common pathogens in neonatal infection.The analysis of biological characteristics was done by bioinformatics. Disk diffusion method and flow cytometry were used to detect the antimicrobial activity of Casein201. Killing kinetics of Casein201 was measured using microplate reader. The antimicrobial mechanism of Casein201 was studied by electron microscopy and electrophoresis.Bioinformatics analysis indicates that Casein201 derived from β-casein and showed significant sequence overlap. Antibacterial assays showed Casein201 inhibited the growth of S taphylococcus aureus and Y ersinia enterocolitica. Ultrastructural analyses revealed that the antibacterial activity of Casein201 is through cytoplasmic structures disintegration and bacterial cell envelope alterations but not combination with DNA.We conclude the antimicrobial activity and mechanism of Casein201. Our data demonstrate that Casein201 has potential therapeutic value for the prevention and treatment of pathogens in neonatal infection.