title: Transcriptional and catalytic responses of antioxidant and biotransformation pathways in mussels, Mytilus galloprovincialis, exposed to chemical mixtures.
abstract: Antioxidant and biotransformation pathways are widely studied in marine organisms exposed to environmental stressors. However, mechanisms of responses and links between different intracellular levels are not always easy to elucidate and conflicting results are frequently observed between molecular and enzymatic data. In this study, transcriptional and catalytic responses of antioxidant and biotransformation parameters were analyzed after a 4-week exposure of a marine invertebrate, Mytilus galloprovincialis, to chemical mixtures from low polluted and highly polluted sediments. A significant, dose-dependent bioaccumulation was observed for polycyclic aromatic hydrocarbons, especially low molecular weight compounds. Among antioxidant defences, catalase and glutathione peroxidases did not exhibit variations in enzymatic activity, while the corresponding gene transcriptions were up- and down-regulated, respectively; unchanged mRNA levels of superoxide dismutase confirmed the non-synchronous pathways of variations for such antioxidants. Biotransformation responses also revealed inconsistent trends between transcriptional and catalytic variations of glutathione S-transferases, and a significant increase in mRNA levels for cytochrome P450 3A1. The overall results indicated that transcriptional responses might be sensitive but do not necessarily correspond to functional changes, being more useful as "exposure" rather than "effect" biomarkers. Data on gene transcription and catalytic activities should be carefully interpreted when assessing the impact of chemical pollutants and additional studies are needed on modulation of post-transcriptional mechanisms by environmental stressors.
authors.affiliation: Dipartimento di Scienze della Vita e dell'Ambiente, Università Politecnica delle Marche, Via Brecce Bianche, 60130 Ancona, Italy.
authors.forename: Maria Elisa
authors.initials: ME
authors.lastname: Giuliani
authors.forename: Maura
authors.initials: M
authors.lastname: Benedetti
authors.forename: Augustine
authors.initials: A
authors.lastname: Arukwe
authors.forename: Francesco
authors.initials: F
authors.lastname: Regoli
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D061745:Antioxidant Response Elements / Q000187:drug effects*; D001483:Base Sequence; D001711:Biotransformation / Q000187:drug effects*; D002374:Catalase / Q000378:metabolism; D003001:Cloning, Molecular; D017931:DNA Primers / Q000235:genetics; D004305:Dose-Response Relationship, Drug; D004785:Environmental Pollutants / Q000493:pharmacokinetics / Q000633:toxicity*; D005786:Gene Expression Regulation / Q000187:drug effects*; D005979:Glutathione Peroxidase / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D007558:Italy; D008522:Mediterranean Sea; D019216:Metals, Heavy / Q000493:pharmacokinetics / Q000633:toxicity; D008969:Molecular Sequence Data; D049878:Mytilus / Q000187:drug effects* / Q000378:metabolism; D011084:Polycyclic Aromatic Hydrocarbons / Q000493:pharmacokinetics / Q000633:toxicity; D060888:Real-Time Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D017931:DNA Primers; D004785:Environmental Pollutants; D019216:Metals, Heavy; D011084:Polycyclic Aromatic Hydrocarbons; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D005982:Glutathione Transferase