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.
Subject(s)
Cnidarian Venoms/isolation & purification , Cytotoxins/isolation & purification , Neurotoxins/isolation & purification , Animals , Biological Assay/methods , Brachyura/drug effects , Chromatography, High Pressure Liquid , Cnidarian Venoms/chemistry , Cnidarian Venoms/toxicity , Cubozoa , Cytotoxins/chemistry , Electrophoresis, Polyacrylamide Gel , Erythrocytes/drug effects , Hemolysis , Lethal Dose 50 , Molecular Weight , Neurotoxins/chemistryABSTRACT
BACKGROUND: Seabather's eruption (SBE) is a highly pruritic dermatosis affecting swimmers and divers in marine waters off Florida, in the Gulf of Mexico, and the Caribbean Sea. Its cause has been attributed to various organisms but recently to the larvae of the schyphomedusa, Linuche unguiculata. OBJECTIVE: We attempted to determine whether immature and adult Linuche cause SBE. METHODS: Episodes of SBE in the Cancun and Cozumel area of the Mexican Caribbean were evaluated during the season of high tourism (January-June). This time corresponds to the moments in the life cycle when the three swimming stages of L unguiculata-ephyrae, medusae, and larvae-can be sequentially observed. Our methods include (1) observations by divers, biologists, and students coinciding with stinging outbreaks and the onset of SBE; (2) serologic evaluation of individuals stung by L unguiculata; and (3) the demonstration of Linuche nematocysts on the affected skin. RESULTS: All 3 swimming Linuche stages can cause SBE. CONCLUSION: The offending stages of Linuche can be identified by the cutaneous lesion's morphology and the time of year.
Subject(s)
Cnidarian Venoms/poisoning , Pruritus/etiology , Skin Diseases, Vesiculobullous/etiology , Adolescent , Adult , Animals , Child , Child, Preschool , Female , Humans , Life Cycle Stages , Male , Middle Aged , Scyphozoa/growth & development , SwimmingABSTRACT
Adult Linuche unguiculata medusae cause seabather's eruption just like that animal's larval form. This observation explains the wide seasonal incidence and the fact that lesions can appear on exposed skin.
