Isolation And Biological Properties Of Neurotoxin From Sea Anemone (Stichodactyla mertensii, S. haddoni)

Abstract

Neurotoxic proteins obtained from sea anemones Stichodactyla mertensii and S. haddoni were assess for neurotoxic activity of the isolated venom and several bioassays were carried out, and the effect of toxin was determined in vivo using sea shore crabs (Ocypode macrocera) the dose causing 50% lethality (LD50). The LD 50 of these two crude extract was obtained as 0.47 mg/kg and 0.71 mg/kg of crude toxic protein was used. The Brine shrimp lethality (LC50) bioassay was performed with Artemia salina nauplii. The LC50 of the S. mertensii was showed higher cytotoxicity (LC 50 = 0.625 mg/ml) than that of S. haddoni (LC 50 = 0.852 mg/ml). The protein patterns of isolated toxin were also analyzed by SDS-PAGE with an apparent molecular weight of 216 kDa (SmNt1), 193 kDa (SmNt2), 95 kDa (SmNt3), 60 kDa (SmNt4) & 46 kDa (SmNt5) and 103 kDa (ShNt1), 82 kDa (ShNt2) & 63 kDa (ShNt3). Neurotoxic activity was estimated by inject a small amount of the crude toxic protein into the third walking leg of a crab and observed the typical convulsions, paralysis, color changes and death provoked by neurotoxins. Hemolytic activity was also estimated as 13 mg/ml, 7 mg/ml in S. mertensii, S. haddoni respectively. The hemolytic values was estimated as 2.46, 4.92, 27.38& 9.85 HT/mg and 2.29, 4.57, 18.29 and 9.14 HT/mg respectively in chicken, cow, goat and human erythrocytes.