Studies On The Extraction Of Nematocyst Venom From Jellyfish And Its Hemolytic And Toxic Activities

Jellyfish toxins are one important protein group of marine medicine leads with unique and novel structures.The characterization of the nematocysts-the jellyfish toxic cells,the extraction of the nematocyst venom and the hemolytic and toxic activity of the nematocyst venom were investigated in this study.Main results are as follows:1.The microscopic,scan and ultrastructure viewes of the nematocysts of Cyanea Sp, Rhopilema esculentum Kishinouye and Stomolophus nomurai Kishinouye exhibited that these jellyfishes contained different types of nematocysts.The mini-bead beater could be used to rupture the nematocysts of jellyfish and to extract the nematocyst venom.2.The Cyanea sp nematocyst venom had strong hemolytic activity.The hemolytic activity was temperature-dependent:at 4℃,no hemolysis occurred;incubation at 37℃for 45min,the hemolytic activity reached to the highest.The venom was sensitive to pH value.The strongest hemolytic activity was found at pH 7.8. Trypsin could greatly inhibit the hemolytic activity.The hemolytic activity was divalent-cations dependent.Ca²⁺ might be an important activator for the hemolysis of the venom,however,it had no effect on the stability of the venom.The presence of EDTA,NaCl and GSH was benefit for the stability of the hemolytic activity.According to the results of orthogonal test,GSH had the strongest effect on the hemolytic activity.3.The protein composition had significant difference between the tentacle extract and the nematocyst extract.The nematocyst extract exhibited sronger hemolytic activity than the tentacle extract.The hemolytic activity:Rhopilema esculentum Kishinouye> Cyanea Sp> Stomolophus nomurai Kishinouye.4.The Cyanea sp nematocyst venom was toxic to fish,producing typical neurotoxin toxicity.The ID₅₀ was about 0.6μg protein/g·fish.Toxic venom was stable when kept at -80℃,but a great loss of the lethality was observed when the venom was stored at -20℃.The toxic activity of the nematocyst venom of Cyanea sp was stabler than other reported jellyfish toxins.Heating at 60℃for 20 min,the venom still had significant lethal effect.Heating at 80℃for 40min or 100℃for 20min totally inactivated the toxicity of the venom.The venom was hydrolyzed by a proteolytic enzyme,trypsin.5.The study on the separation of the Cyanea sp nematocyst venom exhibited that the hemolytic molecular was not toxic to fish.The isoelectric point of the hemolytic component was higher than 7.8 while the toxic component' was lower than 7.8. The separation of the Cyanea sp nematocyst venom using DEAE-Sepharose Fast Flow and Sephadex G-100 mainly yielded two protein bands with molecular weights of 60 kDa and 47 kDa.In conclusion,the different species of jellyfishes contained different toxic nematocysts.The Cyanea sp nematocyst venom had strong hemolytic and toxic activity.The present study established foundations for the separation and characterization of the jellyfish venom,the study on the mechanisms of the venom action and the pharmacology,and the theatment on the jellyfish stings in the future.