title: Molecular responses of European flounder (Platichthys flesus) chronically exposed to contaminated estuarine sediments.
abstract: Molecular responses to acute toxicant exposure can be effective biomarkers, however responses to chronic exposure are less well characterised. The aim of this study was to determine chronic molecular responses to environmental mixtures in a controlled laboratory setting, free from the additional variability encountered with environmental sampling of wild organisms. Flounder fish were exposed in mesocosms for seven months to a contaminated estuarine sediment made by mixing material from the Forth (high organics) and Tyne (high metals and tributyltin) estuaries (FT) or a reference sediment from the Ythan estuary (Y). Chemical analyses demonstrated that FT sediment contained significantly higher concentrations of key environmental pollutants (including polycyclic aromatic hydrocarbons (PAHs), chlorinated biphenyls and heavy metals) than Y sediment, but that chronically exposed flounder showed a lack of differential accumulation of contaminants, including heavy metals. Biliary 1-hydroxypyrene concentration and erythrocyte DNA damage increased in FT-exposed fish. Transcriptomic and (1)H NMR metabolomic analyses of liver tissues detected small but statistically significant alterations between fish exposed to different sediments. These highlighted perturbance of immune response and apoptotic pathways, but there was a lack of response from traditional biomarker genes. Gene-chemical association annotation enrichment analyses suggested that polycyclic aromatic hydrocarbons were a major class of toxicants affecting the molecular responses of the exposed fish. This demonstrated that molecular responses of sentinel organisms can be detected after chronic mixed toxicant exposure and that these can be informative of key components of the mixture.
authors.affiliation: School of Biosciences, The University of Birmingham, Edgbaston, Birmingham B15 2TT, UK. Electronic address: t.d.williams@bham.ac.uk.
authors.forename: Tim D
authors.initials: TD
authors.lastname: Williams
authors.affiliation: Marine Scotland Science, Marine Laboratory, 375 Victoria Rd., Aberdeen AB11 9DB, UK.
authors.forename: Ian M
authors.initials: IM
authors.lastname: Davies
authors.affiliation: School of Biosciences, The University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
authors.forename: Huifeng
authors.initials: H
authors.lastname: Wu
authors.affiliation: Institute of Aquaculture, The University of Stirling, Stirling FK9 4LA, UK.
authors.forename: Amer M
authors.initials: AM
authors.lastname: Diab
authors.affiliation: Marine Scotland Science, Marine Laboratory, 375 Victoria Rd., Aberdeen AB11 9DB, UK.
authors.forename: Lynda
authors.initials: L
authors.lastname: Webster
authors.affiliation: School of Biosciences, The University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
authors.forename: Mark R
authors.initials: MR
authors.lastname: Viant
authors.affiliation: School of Biosciences, The University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
authors.forename: J Kevin
authors.initials: JK
authors.lastname: Chipman
authors.affiliation: Institute of Aquaculture, The University of Stirling, Stirling FK9 4LA, UK.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Leaver
authors.affiliation: Institute of Aquaculture, The University of Stirling, Stirling FK9 4LA, UK.
authors.forename: Stephen G
authors.initials: SG
authors.lastname: George
authors.affiliation: Marine Scotland Science, Marine Laboratory, 375 Victoria Rd., Aberdeen AB11 9DB, UK.
authors.forename: Colin F
authors.initials: CF
authors.lastname: Moffat
authors.affiliation: Marine Scotland Science, Marine Laboratory, 375 Victoria Rd., Aberdeen AB11 9DB, UK.
authors.forename: Craig D
authors.initials: CD
authors.lastname: Robinson
mesh_terms: D000818:Animals; D004249:DNA Damage / Q000187:drug effects; D063366:Estuaries; D005260:Female; D005432:Flounder / Q000235:genetics / Q000502:physiology*; D019015:Geologic Sediments / Q000032:analysis; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008297:Male; D019216:Metals, Heavy / Q000032:analysis / Q000633:toxicity*; D009153:Mutagens / Q000032:analysis / Q000633:toxicity*; D011078:Polychlorinated Biphenyls / Q000032:analysis / Q000633:toxicity*; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis / Q000633:toxicity*; D014158:Transcription, Genetic / Q000187:drug effects; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000633:toxicity*
chemical_list: D019216:Metals, Heavy; D009153:Mutagens; D011084:Polycyclic Aromatic Hydrocarbons; D014874:Water Pollutants, Chemical; D011078:Polychlorinated Biphenyls
keywords: Flounder; Genotoxicity; Metabolomics; Microarray; Sediments; Toxicogenomics