Bactericidal proteins of skin mucus and skin extracts from fresh water fishes, Clarias batrachus and Tilapia mossambicus

Abstract

Fish skin mucus plays a major role in protection against invading pathogens. The present study was aimed to evaluate the bactericidal activity of skin mucus and skin extracts of two freshwater fishes, Clarias batrachus and Tilapia mossambicus. Fish skin mucus and skin extracts were tested against five Gram-negative organisms (Escherichia coli MTCC 443, Pseudomonas aeruginosa MTCC 3541, Aeromonas hydrophila MTCC 7639, Klebsiella pneumoniae MTCC 618, and Proteus vulgaris MTCC 426) and two Gram-positive organisms (Bacillus coagulans MTCC 492 and Staphylococcus aureus MTCC 96). The results showed that skin extracts of both fishes exhibited bactericidal activity. However, C. batrachus showed more activity against the pathogens than T. mossambicus. Protein profiles of extracts were observed by SDS-PAGE. The present investigation suggests that the mucus and skin extracts of C. batrachus and T. mossambicus are the potential sources of bactericidal proteins for pathogenic microorganisms.