Antimicrobial activity of engineered shrimp ovarian peritrophin fragments from fenneropenaeus merguiensis

Shrimp ovarian peritrophin (sop),a major protein in jelly layer and cortical rods,plays a role in egg protection after spawning. previous study,sequence of sop gene from fenneropenaeus merguiensis (fm-sop) was composed of domain a and domain b. the sop domain a contains amino acid sequences between 1-80 of fm-sop. the domain a had six conserved cysteines which have been found in many antimicrobial peptides. the molecular weight of purified rsop-a protein was about 9 kda. the sop domain b contains amino acid sequences 81-329 of fm-sop while sop-b1 was amino acid sequence 182-275 of fm-sop. the molecular weight of purified rhis-sop-b and rhis-sop-b1 protein were about 38.5 and 18.0 kda,respectively. antimicrobial activities of rsop-a,rhis-sop-b and rhis-sop-b1 protein were investigated by liquid growth inhibition assay. minimal inhibition concentration (mic) of rsop-a against staphylococcus aureus,escherichia coli,vibrio harveyi,candida albicans and fusarium oxysporum were 35,280,280,570 and 15 μg/ml,respectively. the mic of rhis-sop-b against s. aureus,v. harveyi and f. oxysporum were 30,270 and 500 μg/ml,respectively. and the mic of rhis-sop-b1 against s. aureus,v. harveyi and f. oxysporum were 20,470 and 250 μg/ml,respectively. the rhis-sop-b and rhis-sop-b1 (1000 μg/ml) did not show antimicrobial activity against e. coli and c. albicans. three purified proteins were able to agglutinate v. harveyi in vitro,displayed a chitinase activity and proteinase inhibition. in addition the stability of the proteins was tested and found decrease antimicrobial activity after incubation at 50 °c for 5 h.