Isolation, Characterization and Pathology of the Toxin From a Microcystis Aeruginosa (= Anacystis Cyanea) Bloom

Abstract

The nature of the toxicity of a bloom of blue-green alga, M. aeruginosa (= Anacystis cyanea), that occurred in a man-made lake was investigated. Crude algal bloom extracts were toxic to laboratory mice when injected intraperitoneaIIy. The lethal dose (LDlOO) of these extracts was 15-30 mg of lyophilized algal bloom per kilogram body weight. The toxin was purified by a procedure that included ammonium sulphate fractionation, solvent extraction, acid precipitation, Sephadex G25 and DEAE-Sephadex chromatography, and high-voltage electrophoresis at pH 6·5. The preparation gave a single spot on high-voltage electrophoresis at pH 9·0, had no free amino group, and was characterized by a simple amino acid composition of equimolar quantities of L-methionine, L-tyrosine, D-alanine, D-glutamic acid, erythro fi-methyl aspartic acid and methylamine.