Biological characterization of omw1 and omw2: antimicrobial peptides derived from omwaprin

Two cationic antimicrobial peptides (AMP) were designed based on the snake venom peptide, omwaprin, hypothesized to be shorter, cost effective and potent. Omw1 and omw2 demonstrated significant broad-spectrum antimicrobial activity against standard and clinical strains at a MIC ranging from 15.625 to 250 µg/ml for omw1 and from 31.3 to 500 µg/ml for omw2. Time–kill kinetics revealed that omw1 caused complete lysis of E. coli ATCC 25922 at 1× MIC and S. aureus ATCC 25923 at 2× MIC after 40 and 60 min of incubation, respectively. Membranolytic activity of the peptides was assessed by propidium iodide stain, where red fluorescence was observed in cells treated with the peptides compared to untreated cells. Notable morphological changes were observed in the microbes treated with peptides, as revealed by scanning electron micrographs. Omw1 and omw2 were also potent to inhibit the formation as well as dispersal of matured biofilms at 1/2× MIC against clinical strain, C. albicans. Further, minimal hemolytic activity demonstrated by both the peptides at microbicidal concentration against human erythrocytes proves that the designed peptides were less toxic and potent antimicrobial agents which could be considered for further studies with animal models to affirm its efficiency.