Isolation , the purification and the identification of Hepatotoxin Microcystin-LR from two cyanobacterial species and studying biological activity on some aquatic organisms


The study was included the isolation , the purification and the cultivation two cyanobacterial species isolated from AL-Khandaq river , Basrah city/ southern of Iraq represented by species Nostoc muscurum ( Agardh) and Anabaena variabilis ( kuetz.) in addition to green algae ( non- toxic alga) Chlorella vulgaris Beijerinck with measuring their growth constant ( K ) and generation time ( G ) . This study showed that the ability of two cyanobacterial species to produce toxins type hepatotoxins ( Microcystin-LR ) as the first time in Iraq especially for the two types above. Hepatotoxin was identified after the extraction and the purification by using HPLC technique ( High performance liquid chromatography ) to detect the purity and the concentration of this toxin , in addition Infra-red technique was used to investigate chemical active groups of hepatotoxoins. The Concentration of hepatotoxins reached to 28.57 µg/ml for alga N. muscurum and 4.61 µg/ml for species A. variabilis respectively . The two cyanobacterial species were used as food for three economic fish larvae represented by Cyprinus carpio L., Hypophthalmicthyes molitrix VaL. and Ctenopharyngodon idella Val. The results showed significant decreasing in mean of weight , length and survival percentage for all fish larvae when fed on toxic species compared with fed on non- toxic species C. vulgaris . Also the results showed toxic effect of two cyanobacterial species on some zooplankton species represented by Artemia salina , Daphnia magna and Brachionus calyciflorous after fed on toxic species . This feeding led to significantly decreasing p≤ 0.05 in the mean numbers of zooplankton compared with those fed on non- toxic microalga C. vulgaris .