Partial purification and characterization of a novel neurotoxin and three cytolysins from box jellyfish (Carybdea marsupialis) nematocyst venom

Abstract

This paper describes one neurotoxin and three cytolysins isolated from the venom of the Caribbean box jellyfish Carybdea marsupialis. To assess the cytolytic and neurotoxic activity of the nematocyst venom, several bioassays were carried out, and to evaluate the effect of the toxin, the dose causing 50% lethality (LD(50)) was determined in vivo using sea crabs (Ocypode quadrata). The proteins with neurotoxic and cytolytic effects were isolated using low-pressure liquid chromatography. The fraction containing the neurotoxic activity was analyzed by SDS-PAGE and showed a single protein band with an apparent molecular weight of 120 kDa (CmNt). To demonstrate the neurotoxic activity of this protein, a small fraction of the purified protein was injected into a crab, and the typical convulsions, paralysis, and death provoked by neurotoxins were observed. Three fractions containing cytolysins had protein bands in SDS PAGE with apparent molecular weights of 220, 139, and 36 kDa, and their cytolytic activity was confirmed with the haemolysis assay.