New Cationic Antimicrobial Peptide Screened from Boiled-Dried Anchovies by Immobilized Bacterial Membrane Liposome Chromatography

An efficient immobilized bacterial membrane liposome chromatography method was used to screen potential antimicrobial peptides from boiled-dried anchovies. A novel cationic antimicrobial peptide (Apep10) was successfully isolated by one-step chromatography. The sequence of Apep10 was identified as GLARCLAGTL by matrix-assisted laser desorption/ionization quadrupole time-of-flight tandem mass spectrometry (MALDI-Q-TOF MS). The antimicrobial activity assessment indicated that Apep10 inhibited the growth of the reference bacteria (Escherichia coli, Shigella dysenteriae, Pseudomonas aeruginosa, Salmonella typhimurium, Staphylococcus aureus, Bacillus subtilis, and Streptococcus pneumoniae), with minimal inhibitory concentration (MIC) values ranging from 8 to 64 mu g/mL. Almost no cytotoxicity against mouse erythrocytes was observed at concentrations below 20 mu g/mL. Nucleotide leakage induced by Apep10 showed that the peptide exhibited permeable activity on the cytoplasmic membrane. Alterations in morphology were observed by scanning electronic microscopy (SEM). Membrane disruption was confirmed by confocal laser scanning microscopy (CLSM) with propidium iodide (PI). The results demonstrate that immobilized bacterial membrane liposome chromatography is a straightforward technique for screening unknown antimicrobial peptides with cell-membrane-interacting activities from boiled-dried anchovies.