title: Impacts of the phenylpyrazole insecticide fipronil on larval fish: time-series gene transcription responses in fathead minnow (Pimephales promelas) following short-term exposure.
abstract: The utilization of molecular endpoints in ecotoxicology can provide rapid and valuable information on immediate organismal responses to chemical stressors and is increasingly used for mechanistic interpretation of effects at higher levels of biological organization. This study contributes knowledge on the sublethal effects of a commonly used insecticide, the phenylpyrazole fipronil, on larval fathead minnow (Pimephales promelas), utilizing a quantitative transcriptomic approach. Immediately after 24h of exposure to fipronil concentrations of ≥31 μg.L(-1), highly significant changes in gene transcription were observed for aspartoacylase, metallothionein, glucocorticoid receptor, cytochrome P450 3A126 and vitellogenin. Different mechanisms of toxicity were apparent over the course of the experiment, with short-term responses indicating neurotoxic effects. After 6 days of recovery, endocrine effects were observed with vitellogenin being up-regulated 90-fold at 61 μg.L(-1) fipronil. Principal component analysis demonstrated a significant increase in gene transcription changes over time and during the recovery period. In conclusion, multiple mechanisms of action were observed in response to fipronil exposure, and unknown delayed effects would have been missed if transcriptomic responses had only been measured at a single time-point. These challenges can be overcome by the inclusion of multiple endpoints and delayed effects in experimental designs.
authors.affiliation: Aquatic Systems Biology Unit, Department of Ecology and Ecosystem Management, Technische Universität München, Mühlenweg 22, D-85354 Freising, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Beggel
authors.forename: Inge
authors.initials: I
authors.lastname: Werner
authors.forename: Richard E
authors.initials: RE
authors.lastname: Connon
authors.forename: Juergen P
authors.initials: JP
authors.lastname: Geist
mesh_terms: D000581:Amidohydrolases / Q000235:genetics / Q000378:metabolism; D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D003530:Cyprinidae; D051544:Cytochrome P-450 CYP3A / Q000235:genetics / Q000378:metabolism; D005260:Female; D015870:Gene Expression / Q000187:drug effects*; D007306:Insecticides / Q000633:toxicity*; D007814:Larva / Q000187:drug effects; D008297:Male; D008668:Metallothionein / Q000235:genetics / Q000378:metabolism; D025341:Principal Component Analysis; D011720:Pyrazoles / Q000633:toxicity*; D011965:Receptors, Glucocorticoid / Q000235:genetics / Q000378:metabolism; D014819:Vitellogenins / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D015415:Biomarkers; D007306:Insecticides; D011720:Pyrazoles; D011965:Receptors, Glucocorticoid; D014819:Vitellogenins; D014874:Water Pollutants, Chemical; D008668:Metallothionein; D051544:Cytochrome P-450 CYP3A; D000581:Amidohydrolases; C019751:aspartoacylase; C082360:fipronil