Seven microcystins from Microcystis waterbloom in Lake Dalai,China

Seven types of microcystins,isolated from Microcystis waterbloom in Lake Dalai, were characterized.The major toxins:MCYST-LR,MCYST-RR,[D-Asp³]MCYST-LR and [Dha⁷]MCYST-LR were identified by high performance liquid chromatography(HPLC),as compared with the authentic microcystins.The minor toxins:MCYST FR,[L-Mser⁷]MCYST-LR and an unknown MCYST which was most likely to be MCYST-(H₄)YR were identified with fritfast atom bombardment liquid chromatography/mass spectrometry(Frit-FAB LC/MS)and amino acid analysis.The toxigenic diversity in blue-green algae(cyanobacteria)was discussed.