title: DNA damage and translational response during detoxification from copper exposure in a wild population of Chironomus riparius.
abstract: Copper is one of the predominant components of pesticides employed in agriculture and known to be highly toxic once it reaches aquatic organisms. The impact of sublethal concentrations of this metal on wild insects is not yet completely understood. Studies addressing alterations in different levels of gene expression are still lacking. We previously demonstrated that in a wild population of Chironomus riparius, HSP and CYP families of genes were up-regulated at the transcriptional level after copper exposure. Here, we analyse the impact of copper at the genomic, translational and protein functional level, obtaining a comprehensive picture of the molecular reply to this metal. We studied genotoxicity in C. riparius larvae by Comet Assay, the translational response by polysomal profiling and the detoxification capacity by the CYP450 enzymes activity. Fourth-instar larvae from a mountain stream polluted by agricultural land run-off (NE-Italy) were exposed for 3 h copper concentrations ≤ LC50. We report DNA damage induced by copper, even at sublethal levels, as demonstrated by significant increases in all the comet parameters at concentrations ≥1 mg L-1. By estimating the transcript-specific translational efficiency, we observe a specific up-regulation of CYP4G. Furthermore, the enzymatic activity of CYP450 enzymes is increased at all sublethal copper concentrations, confirming the role of this protein family in the detoxification processes. Surprisingly, the HSP transcripts are up-regulated at the transcriptional level, but these changes are buffered at the translational level suggesting the existence of still unknown post-transcriptional controls that may be connected to survival processes.
authors.affiliation: Centre for Integrative Biology, University of Trento, Via Sommarive n. 9, 38123, Povo (TN), Trento, Italy; Institute of Biophysics - CNR - Trento Unit, Via Sommarive 18, 38123, Povo, Trento, Italy; Section of Invertebrate Zoology and Hydrobiology, MUSE-Museo delle Scienze, Corso del Lavoro e della Scienza 3, 38123 Trento, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Bernabò
authors.affiliation: Institute of Biophysics - CNR - Trento Unit, Via Sommarive 18, 38123, Povo, Trento, Italy.
authors.forename: Matteo
authors.initials: M
authors.lastname: Gaglio
authors.affiliation: Section of Invertebrate Zoology and Hydrobiology, MUSE-Museo delle Scienze, Corso del Lavoro e della Scienza 3, 38123 Trento, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Bellamoli
authors.affiliation: Institute of Biophysics - CNR - Trento Unit, Via Sommarive 18, 38123, Povo, Trento, Italy.
authors.forename: Gabriella
authors.initials: G
authors.lastname: Viero
authors.affiliation: Section of Invertebrate Zoology and Hydrobiology, MUSE-Museo delle Scienze, Corso del Lavoro e della Scienza 3, 38123 Trento, Italy. Electronic address: valeria.lencioni@muse.it.
authors.forename: Valeria
authors.initials: V
authors.lastname: Lencioni
mesh_terms: D000818:Animals; D002683:Chironomidae / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D020552:Comet Assay; D003300:Copper / Q000633:toxicity*; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics* / Q000378:metabolism; D004249:DNA Damage / Q000187:drug effects*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects*; D008658:Inactivation, Metabolic / Q000187:drug effects; D007558:Italy; D007814:Larva / Q000378:metabolism; D014176:Protein Biosynthesis / Q000187:drug effects*; D015854:Up-Regulation; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D014874:Water Pollutants, Chemical; D003300:Copper; D003577:Cytochrome P-450 Enzyme System
keywords: Biomarkers; Comet assay; Cytochrome P450; Freshwater monitoring; Heat shock proteins; Polysomal profiling