title: Toxicity of Microcystis species isolated from natural blooms and purification of the toxin.
abstract: Microcystis strains (2 toxic and 18 nontoxic to mice) were isolated from toxic waterblooms that had been collected from Lake Kasumigaura, Ibaraki Prefecture, Japan, in August 1985. Thirteen of the strains (2 toxic and 11 nontoxic) were Microcystis aeruginosa, 2 (nontoxic) were Microcystis wesenbergii, and the other 5 were difficult to identify. Six (1 toxic and 4 nontoxic M. aeruginosa and 1 M. wesenbergii) of these 20 strains were established as axenic cultures. A toxic and axenic strain of M. aeruginosa, K-139, was used to study the relationship between growth conditions and toxicity. Cells in early-to-mid-log phase showed the highest toxicity (50% lethal dose, 7.5 mg of cells per kg of mouse), and maximum toxicity was not affected by growth temperatures between 22 and 30 degrees C. Purification and characterization of the toxins from K-139 cells were also conducted, and at least two toxins were detected. One of the toxins (molecular mass, 980 daltons) has not been reported previously. The main target of the toxin in mice was the liver. Marked congestion and necrosis in the parenchymal cells around the central veins of the liver were observed microscopically in specimens that had been prepared from the mice with acute toxicity after injection with the toxin.
authors.affiliation: Department of Agricultural Chemistry, Ibaraki University, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Ohtake
authors.forename: M
authors.initials: M
authors.lastname: Shirai
authors.forename: T
authors.initials: T
authors.lastname: Aida
authors.forename: N
authors.initials: N
authors.lastname: Mori
authors.forename: K
authors.initials: K
authors.lastname: Harada
authors.forename: K
authors.initials: K
authors.lastname: Matsuura
authors.forename: M
authors.initials: M
authors.lastname: Suzuki
authors.forename: M
authors.initials: M
authors.lastname: Nakano
mesh_terms: D000818:Animals; D001681:Biological Assay; D002851:Chromatography, High Pressure Liquid; D005260:Female; D005618:Fresh Water; D007564:Japan; D008099:Liver / Q000187:drug effects / Q000473:pathology; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D051379:Mice; D008810:Mice, Inbred C57BL; D046931:Microcystis / Q000302:isolation & purification* / Q000378:metabolism; D013696:Temperature; D014118:Toxins, Biological / Q000302:isolation & purification / Q000633:toxicity*; D014871:Water Microbiology
chemical_list: D014118:Toxins, Biological