Comparative Study On The Hemolytic And Cytotoxic Activities Of Nematocyst Venoms From The Two Jellyfishes Nemopilema Nomurai And Cyanea Nozakii

Jellyfish nematocysts contain toxic polypeptides or proteins, which mightincrease the health risk during jellyfish blooms. Two giant jellyfishes, Nemopilemanomurai Kishinouye,1922and Cyanea nozakii Kishinouye,1891, which are themajor bloom species in the northern China seas in recent year, were selected to studytheir nematocysts’ tissue distribution, venom content and toxicity. The main resultsare as the following:1. Microscopic observation revealed that both of the two jellyfishes’nematocystswere clustered in the tentacle surface, but C. nozakii was concentrated relative to N.nomurai. The tissue distribution density of C. nozakii nematocyst (14909±349cysts/cm2) was higher than that of N. nomurai (9008±309cysts/cm2). N. nomuraipresented4types of nematocysts, respectively atrichous isorhizas, holotrichousisorhizas, homotrichous microbasic curytele and heterotrichous microbasic curytele. C.nozakii presented3types of nematocysts, respectively atrichous isorhizas,holotrichous isorhizas and merotrichous isorhizas. Most the N. nomurai were spheric,whereas in C.nozakii they were ellipsoidal mostly.2. The nematocysts were ruptured with a Mini-Beadbeater-16to extract thenematocyst venom thereof. Rupture time of120s yielded maximum ruptureefficiency for both species’ nematocysts. Concentration of the extracted venomproteins N. nomurai (0.22mg/mL-0.30mg/mL) was slightly higher than that of C.nozakii (0.18mg/mL-0.28mg/mL).The venom proteins’content per nematocyst of N.nomurai was also slightly higher than that of C. nozakii.3. Both species’ nematocyst venoms might cause hemolysis of red blood cellsfrom chicken, pigeon and sheep and effect was dependent on the dose of the venoms and exposure time. The hemolytic activity of C. nozakii venom to red blood cells fromchicken (72.14μg/mL as EC50-30min), pigeon (73.84μg/mL as EC50-30min) orsheep (63.62μg/mL as EC50-30min) was significantly weaker than that of N. nomuraito the same red blood cells (80.35μg/mL,80.81μg/mL and69.69μg/mL as EC50-30min, respectively). Notwithstanding, the quantity of C. nozakii nematocystsequivalent to hemolytic EC50-30min in1mL reaction with chicken (721cysts or0.048cm2tentacle surface), pigeon (738cysts or0.050cm2tentacle surface), or sheepred blood cells (636cysts or0.043cm2tentacle surface) was similar to that of N.nomurai for the same equivalence (730,735or634cysts, within0.081,0.082or0.070cm2tentacle surface, respectively). The hemolytic effect of both jellyfishvenoms to sheep red blood cells was stronger than to chicken or pigeon red bloodcells. The results indicated that C. nozakii was more effective for hemolysis than N.nomurai per venom, however such effect per nematocyst or unit tentacle surface areawas similar for both jellyfish species. Mammalian red blood cells might presentdifferent sensitivities from that of birds to the jellyfish venoms.4. Both species’ nematocyst venoms could inhibit the survival rates of incubatedA9(mice subcutaneous connective tissue) cells, A-673(human rhabdomyosarcoma)cells and A-431(human epidermoid carcinoma) cells, and the effect was dependent onthe dose of venoms and exposure time. The toxicity of C. nozakii venom to A9cells(49.8μg/mL as EC50-24h), A-673cells (43.6μg/mL as EC50-24h) or A-431cells (40.9μg/mL as EC50-24h) was significantly stonger than that of N. nomurai to the samecell lines (78.0μg/mL,70.1μg/mL and68.6μg/mL as EC50-24h, respectively).Accordingly, the quantity of C. nozakii nematocysts equivalent to cytotoxic EC50-24hin1mL reaction with A9cells (498cysts or0.033cm2tentacle surface), A-673cells(436cysts or0.029cm2tentacle surface), or A-431(409cysts or0.027cm2tentaclesurface) was lower than that of N. nomurai for the same cell lines (709,637or624cysts, within0.079,0.071or0.069cm2tentacle surface, respectively). The jellyfishvenoms were more toxic to the current cell lines than reported Rhizostomeae orSemaeostomeae jellyfish venoms to other cells from the mammalian lung, liver, nerve,blood vessel or mammary gland. The results indicated that C. nozakii was more cytotoxic than N. nomurai, no matter in terms of per venom, per nametocyst or unittentacle surface area; and the skin and striated muscle were sensitive to thecytotoxicity of jellyfish venoms.5. The results indicated that C. nozakii were more toxic than N. nomurai, andhigh concern for C. nozakii is suggested during relevant jellyfish toxic risk treatment.