Characterization, purification and phylogenetic analysis of a cytolysin from the sea anemone Heteractis magnifica of the Indian Ocean

• Published in: Journal of Venomous Animals and Toxins
• Main Authors: S Karthikayalu, V Rama, R Kirubagaran, R Venkatesan
• Format: Article in Journal/Newspaper
• Language: English
• Published: SciELO 2010
• Subjects: Heteractis magnifica; marine toxin; hemolysin; cytolysin; Arctic medicine. Tropical medicine; RC955-962; Toxicology. Poisons; RA1190-1270; Zoology; QL1-991; Arctic; Indian
• Online Access: https://doi.org/10.1590/S1678-91992010000200006; https://doaj.org/article/2fcc79d4db8e4b31a8f2cd3c1f92e1f2

It is well established that sea anemones comprise a rich source of cytolytic toxins. The present study reports the isolation and characterization of a cytolysin obtained from the sea anemone Heteractis magnifica collected in the Andaman Islands of the Indian Ocean. The crude extract was screened for hemolytic activity by a blood agar plate method and a 6-mm zone of clearance was observed after incubation. The hemolytic property of the crude extract, tested by the microtiter plate method, revealed positive results at concentrations as low as 120 ng/mL. Furthermore, it was favored by alkaline pH and was stable up to 60°C. On the other hand, the hemolytic effect was abolished by the addition of human serum. Purification steps involved ammonium sulfate precipitation and subsequent desalting by dialysis, followed by anion- and cation-exchange chromatographies. The purified fractions displayed the presence of a 19-kDa cytolysin when analyzed by SDS-PAGE. The conserved region of the cytolysin (with 303 bp) was amplified by RT-PCR and was sequenced. The sequence showed maximum homology (97%) with the already reported cytolysins from other sea anemone species.