Toxicity of the Surgeonfishes-II

Specimens of surgeonfish Ctenochaetus striatus collected in Tahiti contained a water-soluble toxin in addition to ciguatoxin. The water-soluble toxin was tentatively named maitotoxin (MT) after the Tahitian name for surgeonfish maito. Purification of MT was achievable by the standard purification procedures for polar lipids. The toxin was eluted from a silicic acid column with chloroform-methanol (6:4) and from a cellulose column with chloroform-methanol-methanol-water (5:15:1). Upon gel-filtration through Sephadex G-25, it appeared in the fractions near void volume. Acid hydrolysis of the toxin afforded fatty acids, glucose and galactose, and 15 amino acids. The minimum lethal dose to mice by ip injection was estimated to be 15-20mg/kg. Guppies put in 40 ppm solution of MT died within 150min. These chemical and physiological properties indicated a close similarity of MT to the ichthyotoxin produced by the phytoflagellate Prymnesium parvum.