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(22-33) Cellular responses elicited by cyanobacterial toxins in a rainbow trout liver cell line. Teneva, Ivanka*,1, Schirmer, Kristin2, Mladenov, Rumen1, Schüürmann, Gerrit2, 1 University of Plovdiv, Plovdiv, Bulgaria2 UFZ Centre for Environmental Research, Leipzig, Germany ABSTRACT- Cellular responses elicited by cyanobacterial toxins in a rainbow trout liver cell line. Teneva, I.1, K. Schirmer2, R. Mladenov1, G. Schüürmann2. 1University of Plovdiv, Bulgaria; 2UFZ Centre for Environmental Research, Leipzig, Germany. Biologically active compounds produced by cyanobacteria can be a blessing and a curse. Glycolipids produced by certain freshwater cyanobacteria were found to possess anti-tumor activity. In contrast, potent hepatotoxins are produced by a number of genera of cyanobacteria. Death of humans, as well as domestic and wild animals has been linked to high doses of cyanobacterial hepatotoxins, whereas low doses appear to cause liver swelling and potentially tumor promotion. Studies on the toxic mechanisms elicited by cyanotoxins have so far focussed on mammals, using whole animals or cell bioassays. Yet, little is known about the effects of cyanotoxins to fish. Thus, we have investigated the responses elicited by five species of the genus Phormidium and one species of the genus Lyngbya (PACC - Plovdiv Algal Culture Collection) in the rainbow trout liver cell line, RTL-W1. Cyanobacteria were grown in culture and concentrations of up to 50% of this culture medium were used for 24 h exposures to the fish liver cells. The culture medium of Lyngbya and two species of Phormidium caused distinct dose-response relationships in RTL-W1 cells as assessed using three fluorescent indicator dyes. The indicator dyes were alamar Blue, 5-carboxyfluorescein diacetate acetoxymethyl ester (CFDA-AM) and neutral red, which measure metabolic activity, cell membrane integrity and lysosomal membrane function, respectively. In all cases of significant cytotoxicity, alamar Blue and neutral red were more sensitive indicators than CFDA-AM, thereby implying a mechanism that is distinct from general membrane damage. In fact, changes in cell morphology hint at cytoskeletal impairment. Future work will focus on the changes in gene expression and biochemical parameters leading to the cellular responses observed. Key words: cyanobacteria, cytotoxicity, rainbow trout liver cells RTL-W1 |
