ABSTRACT
This study examined differences in the nematocyst ratios between two species of Australian cubozoans. In Chiropsalmus sp., a species that feeds exclusively on shrimp, no changes in the ratio of the three groups of nematocyst present in the cnidome were detected with size of the individual animals. In Chironex fleckeri, the ratio of different types of nematocysts in the cnidome for small animals (less than 40 mm) was similar to that of Chiropsalmus sp. However, with an increase in body size in C. fleckeri, the nematocyst ratio changed, with mastigophores (nematocysts believed to hold the lethal venom component for prey) increasing in proportion. The change in cnidome ratio is correlated with a change in the prey of C. fleckeri with increased size. Small C. fleckeri appeared to feed exclusively on prawns, medium sized animals fed on fish and prawns and large animals fed predominantly on fish. An increase in the proportion of mastigophores (and presumably the lethal venom component) in the cnidome of C. fleckeri may also be responsible for why this species has caused numerous human fatalities, while the Australian Chiropsalmus sp. has not.
Subject(s)
Cnidarian Venoms/toxicity , Cubozoa/physiology , Animals , Bites and Stings/pathology , HumansABSTRACT
Chironex fleckeri, the northern Australian box jellyfish produces one of, if not, the most potent animal venoms. Study of the venom has been hampered by the limits of the animals' range and the venom's thermolability. Using retained lethality and native polyacrylamide gel electrophoresis (NPAGE), we show that lyophilization of autolysis isolated nematocysts is an effective method of transporting the venom. In addition, Sephadex G-200 chromatography, spin concentration, and NPAGE fail to demonstrate the presence of a 600 kDa protein to which the bulk of the lethal activity has been ascribed. Sodium dodecyl sulfate capillary electrophoresis of crude venom yields several protein bands with a molecular weight range of 30-200 kDa. Freeze-thaw studies show a loss of activity and NPAGE bands after two freeze thaw cycles.
Subject(s)
Cnidarian Venoms/isolation & purification , Scyphozoa/chemistry , Animals , Chromatography, Ion Exchange , Cnidarian Venoms/chemistry , Cnidarian Venoms/toxicity , Electrophoresis, Capillary , Electrophoresis, Polyacrylamide Gel , Molecular Weight , Northern TerritoryABSTRACT
Ovine antivenom prolonged survival in mice challenged with intravenous Chironex fleckeri venom over a limited dose range. Verapamil enhanced the beneficial effect of ovine antivenom. This data suggests that there may be an, as yet undefined, optimal antivenom dose for humans and that verapamil, used in combination with antivenom is an effective agent.