Genotoxicity of microcystic cyanobacteria extract of a water source in China

The water pollution of toxic cyanobacteria (blue-green algae) is a worldwid e problem and worsens with industrialization. Microcystins are potent cycli c heptapeptidic hepatotoxins produced mainly by Microcystis aeruginosa, and their hepatotoxicity has been well-documented. In contrast, information on the genotoxic effects of microcystins is relatively scarce. In our present study, the genotoxicity of microcystic cyanobacteria extract (MCE) of a wa ter source in China was studied using Salmonella typhimurium assay (Ames te st), comet assay (Single cell gel electrophoresis) and mouse micronucleus t est. Results from Ames test indicated that MCE had strong mutagenicity rega rdless of the presence of S9. Moreover, MCE was able to induce DNA damage i n primary cultured rat hepatocytes examined by comet assay. In addition, MC E also enhanced bone marrow micronucleated polychromatic erythrocytes in mi ce. The analysis of HPLC showed that the main component of MCE was microcys tin-LR. The understanding of the potent genotoxicity of MCE will help to es tablish the possible link between water cyanobacteria contamination and hig h risk of primary liver cancer found in some endemic areas. (C) 1999 Elsevi er Science B.V. All rights reserved.