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2B - Natural Stressors and Toxicants (TUP/74) Photoinduced acute lethality and sublethal effects of retene to coregonid larvae. Vehniäinen, Eeva1, Häkkinen, Jani1, Oikari, Aimo1, 1 Environmental Sciences, University of Jyväskylä, Jyväskylä, Finland ABSTRACT- Photoinduced toxicity of polynuclear aromatic hydrocarbons (PAHs) is one of the indirect effects of enhanced UV-B radiation. We investigated the effect of simultaneous retene, a resin acid derived PAH, and UV-B on mortality and levels of CYP1A and HSP70 in newly hatched larvae of whitefish and vendace. Whitefish and vendace larvae were pre-exposed to 10 - 100 mg/l and 3.2 - 100 mg/l retene, respectively, and irradiated 3 h daily on two days with UV-B (CIE-weighted daily doses 2.8 or 5.4 kJ/m2 for whitefish and 5.4 kJ/m2 for vendace) or with visible light only. Levels of CYP1A and HSP70 were measured by Western blotting. Neither UV-B nor retene on their own caused mortality. Simultaneous retene and UV-B exposure caused very high mortality to both species (LC50 values of whitefish 13 mg/l and 14 mg/l for the high and low doses of UV-B, respectively, and of vendace 25 mg/l). Retene upregulated CYP1A both in the prescence and absence of UV-B in both species. In whitefish the upregulation was greatest with the second largest concentration of retene but in vendace it was approximately proportional to the concentration of retene. UV-B caused CYP1A induction (10% of maximal induction) in whitefish but not in vendace. Unlike in vendace, both UV-B and retene upregulated HSP70 in larvae of whitefish. Results show that the two species exposed simultaneously to retene and UV-B differ in addition to mortality also in the induction of CYP1A and HSP70 as sublethal responses. Key words: UV-B, phototoxicity, retene |
