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2B - Natural stressors and toxicants (TU13/11) Cyanobacteria - an in vitro approach to studying their toxic potential to mammals and fish. Schirmer, Kristin1, Teneva, Ivanka1, 3, Dzhambazov, Balik2, Mladenov, Ruben3, 1 UFZ Centre for Environmental Research, Leipzig, Germany, Germany3 University of Plovdiv, Plovdiv, Bulgaria, Bulgaria2 Lund University, Lund, Sweden, Sweden ABSTRACT- Toxins produced by cyanobacteria (blue-green algae) have been reported in marine- as well as fresh-water environments throughout the world. Improved analytical detection methods and increased occurrence of cyanobacterial blooms due to eutrophication of many waterbodies are raising awareness of cyanobacterial toxins as a potential risk to environmental health. Recently, cyanobacterial toxins have been found not only at high levels in surface water but also at low, sublethal levels in drinking water. Yet, despite a growing awareness of the presence of cyanobacterial toxins in general, knowledge about the ability of specific species to produce toxic compounds is still rather limited and investigations on toxic mechanisms are directed mostly towards human health using mice. Thus, we pursue the application of in vitro cell cultures from both mammals and fish in order to investigate the toxic potential of individual cyanotoxins, of extracts of cyanobacteria or of cyanobacterial growth medium, as well as of environmental samples. For example, using a combination of cell viability assays, we identified five freshwater species of Phormidium and one of Lyngbya as being toxigenic to both fish and mammalian cells. Fish cells generally appeared less sensitive than mammalian cells and this could be attributed, at least in part, to exposure temperature. Chemical analyses and single-compound toxicity evaluations revealed that none or only a fraction of the observed cytotoxicity could be explained by commonly analysed cyanotoxins, such as microcystin and saxitoxin. To further elucidate the mechanisms of toxicity, and to identify potential markers of sublethal effects, we are currently employing molecular techniques to identify genes that are regulated by cyanobacterial toxins. Key words: toxins, cyanobacteria, in vitro toxicity, teleost and mammalian cell line models |
