title: Toxicity and toxins of natural blooms and isolated strains of Microcystis spp. (Cyanobacteria) and improved procedure for purification of cultures.
abstract: All samples of cyanobacterial blooms collected from 1986 to 1989 from Lake Kasumigaura, Ibaraki Prefecture, Japan, were hepatotoxic. The 50% lethal doses (LD50s) of the blooms to mice ranged from 76 to 556 mg/kg of body weight. Sixty-eight Microcystis cell clones (67 Microcystis aeruginosa and 1 M. viridis) were isolated from the blooms. Twenty-three strains (including the M. viridis strain) were toxic. However, the ratio of toxic to nontoxic strains among the blooms varied (6 to 86%). Microcystins were examined in six toxic strains. Five toxic strains produced microcystin-RR, -YR, and -LR, with RR being the dominant toxin in these strains. Another strain produced 7-desmethylmicrocystin-LR and an unknown microcystin. This strain showed the highest toxicity. Establishment of axenic strains from the Microcystis cells exhibiting extracellularly mucilaginous materials was successful by using a combination of the agar plate technique and two-step centrifugation.
authors.affiliation: Department of Agricultural Chemistry, Ibaraki University, Ibaraki, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Shirai
authors.forename: A
authors.initials: A
authors.lastname: Ohtake
authors.forename: T
authors.initials: T
authors.lastname: Sano
authors.forename: S
authors.initials: S
authors.lastname: Matsumoto
authors.forename: T
authors.initials: T
authors.lastname: Sakamoto
authors.forename: A
authors.initials: A
authors.lastname: Sato
authors.forename: T
authors.initials: T
authors.lastname: Aida
authors.forename: K
authors.initials: K
authors.lastname: Harada
authors.forename: T
authors.initials: T
authors.lastname: Shimada
authors.forename: M
authors.initials: M
authors.lastname: Suzuki
mesh_terms: D000818:Animals; D001427:Bacterial Toxins; D002498:Centrifugation; D002851:Chromatography, High Pressure Liquid; D000087522:Cyanobacteria Toxins; D005068:Eutrophication; D007928:Lethal Dose 50; D008297:Male; D008387:Marine Toxins / Q000302:isolation & purification* / Q000633:toxicity; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D052998:Microcystins; D046931:Microcystis / Q000032:analysis / Q000254:growth & development* / Q000472:pathogenicity / Q000502:physiology; D014774:Virulence; D014871:Water Microbiology
chemical_list: D001427:Bacterial Toxins; D000087522:Cyanobacteria Toxins; D008387:Marine Toxins; D052998:Microcystins