Antibacterial activity of crab haemocyanin against clinical pathogens

Abstract

The increasing antibiotic resistance among pathogenic bacteria is a challenge that drives the development of new antibacterial substances. Marine inhabitants are excellent sources of antimicrobial proteins and considered as promising candidates for the treatment of microbial infections. In the present study, we obtained haemocyanin from Eriphia verrucosa and studied its potential to suppress the growth of some pathogenic bacteria and yeasts. The putative antibacterial molecules were isolated from the haemolymph by chromatography appropriate for producing the native haemocyanin (EvH) and its five structural units (SUs). The results showed that EvH had no antimicrobial activity unlike its glycosylated SUs. All haemocyanin SUs exhibited differential antibacterial activity depending on their grade of glycosylation. The strongest antimicrobial activity of SU1 (with highest carbohydrate content) was against Escherichia coli and Bacillus subtilis. The least glycosylated SU3 and SU4 exhibited the lowest antimicrobial activity against all strains. The fraction SU1 has the potential to be applied as a substitute for some commonly used antibiotics. It was demonstrated that the grade of haemocyanin glycosylation plays an important role in its functional antibacterial properties.