Separation of two myotoxins from nematocysts of the box jellyfish (Chironex fleckeri).

Two myotoxins, both lethal to mice by i.v. injection, were obtained by chromatography on Sephadex G-200 of material released from isolated microbasic mastigophores of C. fleckeri. Both toxins elicit contractures of skeletal (diaphragm) musculature of the rat and of smooth (ileum and vas deferens) and atrial musculature of the guinea-pig, although consistent differences in the parameters of the contractures of each muscle type elicited by the two toxins are shown. Moreover, one toxin, with a molecular weight of approximately 150,000, also elicits activity on crustacean (barnacle) musculature, whilst the other toxin, with a molecular weight of approximately 600,000, elicits no activity in barnacle musculature at the concentrations tested. The toxins are labile when released from nematocysts and they lose all myotoxic activity within 3 days at 5 degrees C. They can also be isolated chromatographically from crude extracts of the contents of mixed nematocysts of C. fleckeri. They are considered to be the principal toxins injected by C. fleckeri during nematocyst discharge and appear to be different from the C. fleckeri toxins described by other workers.