Antimicrobial activity of the crude peptide extracts from Blackfin sea catfish Arius jella Day, 1877

Most Antimicrobial Peptides (AMPs) reported from fish possess antimicrobial activity. The study reports the antibacterial potential of the crude peptide extract from Arius jella, Blackfin sea catfish. The crude peptide extract was purified by a three-step process, namely acetic acid-acetone precipitation, Sep-pak®C-18 solid-phase purification, and cation exchange chromatography. The disc diffusion assay revealed that the crude extract obtained through the modified acetic acid-acetone precipitation method exhibited antimicrobial activity against both Gram-negative and Gram-positive bacteria in all tested cases. The Sep-Pak purification yielded 5, 40, and 80 % fractions of the peptide, and these fractions underwent cation exchange chromatography. The peptide fractions (purified) were further tested for antimicrobial activity by broth microdilution assay. The fractions Aj5-5, Aj40-4, and Aj80-2 showed the highest activity against Bacillus cereus; Aj5-5, Aj40-5, and Aj80-2 against Vibrio alginolyticus; and Aj5-1, Aj40-1, and Aj80-4 showed highest activity against Staphylococcus aureus. All the fractions tested were found to be potent against at least one of the pathogens tested. This is the first report of the isolation of AMPs from Arius jella. Further purification and characterization of the peptides could potentially unveil novel therapeutic agents to combat pathogens and would be a substantial contribution to the field of aquaculture and human health management.