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(473) Toxinology of Microcystis isolated strains form various Moroccan water-bodies. Oudra, Brahim1, Loudiki, Mohammed1, Sabour, Brahim2, Vasconcelos, Vitor3, 1 2 3 ABSTRACT- Cyanotoxins harmful effects on human and animal health have been recognized particularly in countries where drinking water supplies are contaminated by toxic cyanobacteria. In Morocco, cyanobacteria blooms are common in some water bodies used for recreational and/or drinking water reservoirs. In order to avoid any sanitary hazard, there is a need to establish a cyanotoxins national monitoring program. During the cyanobacteria survey, many sites including rivers, ponds and reservoirs in central regions of Morocco, have been prospected. Many toxic cyanobacterium strains mainly represented by Microcystis genus, have been screened. In this paper we present a results of toxinological studies of the some of these forming-blooms cyanobacterial species isolated from various water-bodies particularly Microcytis aeruginosa, Microcystis ichthyoblabe and Microcytis wesenberjii. These strains cultured on Z8 medium under controlled laboratory conditions presented a positive mouse bioassay with evident signs of hepatotoxicity. The content of microcystins was determined by the Enzyme-linked immunosorbent assay (ELISA). The amount of microcystin contents are ranged from 29.6 to 944 micrograms/g. The isolation and identification of Mcyst-LR and other microcystin variants have been performed by high performance liquid chromatography with photodiode array (HPLC-PDA) detection. The result shows that M. ichthyblabe present a maximum of 11 variants whereas M. aeruginosa and M. wesenberjii strains produce only one variant. Under the laboratory culture conditions, the Mcyst-LR has not been detected in the analyzed strains. By using the curve calibration, the concentration of these detected microcystins variants have been determined. The results will be presented and discussed. Key words: Cyanobacteria, Microcystis, Microcystins, Morocco |
