DNA damage and transcriptional changes in the gills of mytilus galloprovincialis exposed to nanomolar doses of combined metal salts (Cd, Cu, Hg)

Aiming at an integrated and mechanistic view of the early biological effects of selected metals in the marine sentinel organism Mytilus galloprovincialis, we exposed mussels for 48 hours to 50, 100 and 200 nM solutions of equimolar Cd, Cu and Hg salts and measured cytological and molecular biomarker...

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Bibliographic Details
Published in:PloS one 2013-01, Vol.8 (1), p.e54602
Main Authors: Varotto, Laura, Domeneghetti, Stefania, Rosani, Umberto, Manfrin, Chiara, Cajaraville, Miren P, Raccanelli, Stefano, Pallavicini, Alberto, Venier, Paola
Format: Article
Language:English
Subjects:
Abnormalities
Actin
Alzheimer's disease
Animals
Annotations
Apoptosis
Atomic absorption analysis
Bioaccumulation
Bioindicators
Biological effects
Biological magnification
Biology
Biomarkers
Bivalvia
Cadmium
Cell cycle
Chemical bonds
Chemical synthesis
Contaminants
Copper
Deoxyribonucleic acid
DNA
DNA Damage
DNA methylation
Earth Sciences
Exposure
GADD45 protein
Gene expression
Gene Expression Regulation - drug effects
Gene sequencing
Genes
Genetic aspects
Gills
Gills - metabolism
Heat shock proteins
Heavy Metal Poisoning
Homeostasis
Life sciences
Ligands
Medicine
Mercury
Metals
Metals, Heavy - metabolism
Metals, Heavy - pharmacology
Micronuclei
Mollusks
Mussels
Mytilus - metabolism
Oxidative stress
Permeability
Poisoning - metabolism
Proteasomes
Protein binding
Protein biosynthesis
Protein synthesis
Protein turnover
Proteins
Salts
Spectral analysis
Spectrometry
Structure-function relationships
Transcription
Transcription (Genetics)
Transcription, Genetic - drug effects
Veterinary Science
Water pollution
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Summary:Aiming at an integrated and mechanistic view of the early biological effects of selected metals in the marine sentinel organism Mytilus galloprovincialis, we exposed mussels for 48 hours to 50, 100 and 200 nM solutions of equimolar Cd, Cu and Hg salts and measured cytological and molecular biomarkers in parallel. Focusing on the mussel gills, first target of toxic water contaminants and actively proliferating tissue, we detected significant dose-related increases of cells with micronuclei and other nuclear abnormalities in the treated mussels, with differences in the bioconcentration of the three metals determined in the mussel flesh by atomic absorption spectrometry. Gene expression profiles, determined in the same individual gills in parallel, revealed some transcriptional changes at the 50 nM dose, and substantial increases of differentially expressed genes at the 100 and 200 nM doses, with roughly similar amounts of up- and down-regulated genes. The functional annotation of gill transcripts with consistent expression trends and significantly altered at least in one dose point disclosed the complexity of the induced cell response. The most evident transcriptional changes concerned protein synthesis and turnover, ion homeostasis, cell cycle regulation and apoptosis, and intracellular trafficking (transcript sequences denoting heat shock proteins, metal binding thioneins, sequestosome 1 and proteasome subunits, and GADD45 exemplify up-regulated genes while transcript sequences denoting actin, tubulins and the apoptosis inhibitor 1 exemplify down-regulated genes). Overall, nanomolar doses of co-occurring free metal ions have induced significant structural and functional changes in the mussel gills: the intensity of response to the stimulus measured in laboratory supports the additional validation of molecular markers of metal exposure to be used in Mussel Watch programs.
ISSN:1932-6203
1932-6203
DOI:10.1371/journal.pone.0054602