|
2B - Natural stressors and toxicants (TU13/12) Toxicity of heterocystous cyanobacteria from Portugal. Osswald, Joana1, 2, Saker, Martin2, Vasconcelos, Vítor1, 2, 1 Faculty of Sciences, University of Porto, Porto, Portugal, Portugal2 CIIMAR, Porto, Portugal, Portugal ABSTRACT- As it happens in the rest of the world, in Portugal the most common and the better studied cyanotoxins are microcystins produced by Microcystis aeruginosa . This species which is hepatotoxic to mice, has been detected as a component of the phytoplankton in many Portuguese water bodies. However, results of routine counts of phytoplankton from several health authauroties and from our laboratory indicated occurrences of other potentially toxic groups of cyanobacteria. These groups include the heterocystous genera of which there is scarce information about their toxin production. 10 isolates of heterocystous cyanobacteria (five Anabaena spp. , one Cylindrospermopsis raciborskii and four Aphanizomenon spp. ) were obtained from Maranhão Reservoir (a large water body used for recreational and agriculture purposes in the south of Portugal). Taxonomic classification was done using morphometric characteristics. Toxicity was analysed using the comercial ELISA test kit EMPK (Enviro®Gard Microcystin Plate Kit, 75400. Strategic Diagnostic Inc.) and also by the HPLC method for microcystins. Finally, mice bioassays were carried out (survival time, symptoms and post-mortem examination) in order to determine the toxicity of the cultivated strains. Five strains were lethal to mice indicating putative public health-risks. Acknowledgements: CYANOTOX project (ENV4-CT98-0802) Key words: bioassay, cyanotoxins, health-risk, phytoplankton |
