SPECIFICITY AND SOME PHYSICOCHEMICAL CHARACTERISTICS OF THE ANTIBACTERIAL ACTIVITY FROM BLUE-CRAB CALLINECTES-SAPIDUS

Haemolymph of the brachyuran crustacean Callinectes sapidus possesses bactericidal activity which is highly inhibitory to Gram-negative bact eria cultured from blue crab carapace, including Aeromonas hydrophila, Vibrio parahemolyticus, Vibrio alginolyticus and Vibrio vulnificus. S everal strains of Escherichia coli were also susceptible, but all othe r bacteria that were not isolated from blue crabs were resistant. No l ysozyme-like activity was detected. A quantitative turbidometric assay using E. coli was used to measure antibacterial activity after exposu re to various physical and chemical treatments. The activity was most active at low pH, heat labile, inhibited by sodium chloride, and inact ivated by protease. The antibacterial activity appeared to be confined to the haemocytes. (C) 1996 Academic Press Limited