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Dynamic transcriptomic profiles of zebrafish gills in response to zinc exposure
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Abstracts / Comparative Biochemistry and Physiology, Part A 157 (2010) S35–S39
3. Nuclear proteome changes in Dictyostelium discoideum during adaptations to mercury L. Boatti, F. Marsano, A. Negri, A. Viarengo (University of Piemonte Orientale, DiSAV, Italy) Living organisms respond to adverse environmental conditions activating a number of molecular mechanisms which, in turn, allow them to adapt to the new environmental conditions. Such mechanisms are the outcome of a tight cross-talk among several different cellular components (ranging from signal transduction to the control of gene expression) which are so far poorly characterized and mostly unknown. This work aims to deepen the analysis of changes in the nuclear proteome of a model organism, the social amoeba Dictyostelium discoideum in relation to exposure to a heavy metal widely distributed in soil and waters: mercury. The nuclear protein modifications represent a crucial point in the actuation of stress response, as can be seen as a hub between signal transduction events and realization of new gene expression/protein synthesis, phenomena which in turn may lead to the establishment of detoxification and adaptation processes to new environmental conditions. The proteins extracted from nuclei of control's cells and treated with mercury were labelled using Isotope-coded protein label (ICPL) and then analysed by LC–ESI MS/MS. We have identified about 100 peptides, their main post-translational modifications, and quantitative variations induced by mercury treatment on different proteins such as histones and other proteins that should play a role in the nuclear processes. Histones – between the nuclear proteins – are highly conserved and they do not play simply a structural role, but post-translational modifications at specific aminoacid residues can greatly influence gene expression. These data represent a link between genomics and proteomics and provide information on the regulation of gene expression in Dictyostelium exposed to mercury. doi:10.1016/j.cbpa.2010.06.101
4. Dynamic transcriptomic profiles of zebrafish gills in response to zinc exposure C. Hogstrand, D. Zheng, P. Cunningham (King's College London, UK); P. Kille, G.P. Feeney (Cardiff University, UK); R.D. Handy (University of Plymouth, UK) Zinc is an essential micronutrient and an aquatic pollutant of concern. The fish gill is an important locus for zinc toxicity as well as for acclimation to elevated zinc. We exploited the tractability of the zebrafish gill to study time-dependent regulatory networks of geneexpression leading to zinc acclimation. Fish were exposed to zinc in water (260 μg L−1) and diet (2023 mg zinc kg−1) and compared to fish kept at control condition ([Zn(II)] water: 16 μg L−1, diet: 233 mg kg−1). Gill tissues were harvested at five time points up to 14 days and transcriptome changes analysed in quintuplicate with results anchored to physiological variables. In total, 525 genes were regulated (1.8 Fold-Change, 10% FDR) by zinc exposure. The number of regulated genes increased up to day seven and declined thereafter. Many genes displayed cyclic expression patterns, typical for homeostatic control mechanisms. Annotation enrichment analysis revealed strong overrepresentation of developmental genes and of transcription factors, such as steroid hormone receptors. Early regulation of genes was coordinated by a few key transcription factors and
followed by hedgehog and bone morphogenic protein signalling. The results suggest that zinc exposure reactivated developmental pathways in the gill and stimulated stem cell differentiation, a response likely reflecting gill remodelling in response to exposure. This provides insight to the mechanisms of zinc toxicity and acclimation as well as roles of zinc in biology. The study also highlights the importance of temporal transcriptomics analysis in order to resolve the discrete elements of biological processes, such as zinc acclimation. doi:10.1016/j.cbpa.2010.06.102
5. Effects of hexavalent chromium in Mytilus galloprovincialis L. Canesi, C. Barmo, R. Fabbri, S. Olivieri, G. Gallo (Dipartimento di Biologia, Università di Genova, Italy); L. Boatti, F. Dondero, A. Viarengo (University of Piemonte Orientale, DISAV, Italy) Hexavalent chromium Cr(VI) is an important contaminant released from both domestic and industrial effluents, representing the predominant chemical form in aquatic ecosystems. Cr(VI) is a model oxidative toxicant due to its intracellular reduction to the biologically active Cr(III) form and ROS production. Moreover, recent evidence suggests that chromium may interfere with the endocrine systems, in particular acting as a ‘metalloestrogen’. In this work, the effects of Cr(VI) were investigated in the marine bivalve Mytilus galloprovincialis. Mussels were exposed to Cr(VI) for 96 h (0.01–100 μg/animal/L) and different endpoints were evaluated in different tissues. The highest concentration induced severe stress conditions in the animals. At lower concentrations significant changes in lysosomal biomarkers in both hemocytes and digestive gland were observed. Cr(VI) also induced stimulation of antioxidant enzyme activities (catalase and GST) and lysosomal lipofuscin accumulation, indicating oxidative stress conditions. Moreover, changes in PES (Protein Expression Signature) in hemolymph serum, as evaluated by 2D electrophoresis were observed. Interestingly, in male digestive gland, Cr(VI) induced significant changes in the level of transcripts for Mytilus Estrogen Receptors (MeERs) and serotonin (5-HT) receptors, as evaluated by RT-Q-PCR, supporting the hypothesis that this metal may have significant endocrine disrupting properties in marine bivalves. The results demonstrate that environmental concentrations of Cr (VI) induce a wide range of responses in mussel tissues, with concentration-, tissue- and sex-related differential effects. Supported by the Italian Ministry of Research (PRIN2007) and by Fondazione CARIGE (prot. 2009.0659-42). doi:10.1016/j.cbpa.2010.06.103
6. Trace metals modulate gene expression and efflux activity of ABC transport proteins in the PLHC-1 fish cell line C. Della Torre (Department of Environmental Sciences, “G. Sarfatti” Università di Siena, Italy); R. Zaja, J. Loncar (Laboratory for Molecular Ecotoxicology, Division for Marine and Environmental Research, Ruđer Bošković Institute, Zagreb, Croatia); S. Focardi (Department of Environmental Sciences, “G. Sarfatti” Università di Siena, Italy); T. Smital (Laboratory for Molecular Ecotoxicology, Division for Marine and Environmental Research, Ruđer Bošković Institute, Zagreb, Croatia); I. Corsi (Department of Environmental Sciences, “G. Sarfatti” Università di Siena, Italy)
Abstracts / Comparative Biochemistry and Physiology, Part A 157 (2010) S35–S39
3. Nuclear proteome changes in Dictyostelium discoideum during adaptations to mercury L. Boatti, F. Marsano, A. Negri, A. Viarengo (University of Piemonte Orientale, DiSAV, Italy) Living organisms respond to adverse environmental conditions activating a number of molecular mechanisms which, in turn, allow them to adapt to the new environmental conditions. Such mechanisms are the outcome of a tight cross-talk among several different cellular components (ranging from signal transduction to the control of gene expression) which are so far poorly characterized and mostly unknown. This work aims to deepen the analysis of changes in the nuclear proteome of a model organism, the social amoeba Dictyostelium discoideum in relation to exposure to a heavy metal widely distributed in soil and waters: mercury. The nuclear protein modifications represent a crucial point in the actuation of stress response, as can be seen as a hub between signal transduction events and realization of new gene expression/protein synthesis, phenomena which in turn may lead to the establishment of detoxification and adaptation processes to new environmental conditions. The proteins extracted from nuclei of control's cells and treated with mercury were labelled using Isotope-coded protein label (ICPL) and then analysed by LC–ESI MS/MS. We have identified about 100 peptides, their main post-translational modifications, and quantitative variations induced by mercury treatment on different proteins such as histones and other proteins that should play a role in the nuclear processes. Histones – between the nuclear proteins – are highly conserved and they do not play simply a structural role, but post-translational modifications at specific aminoacid residues can greatly influence gene expression. These data represent a link between genomics and proteomics and provide information on the regulation of gene expression in Dictyostelium exposed to mercury. doi:10.1016/j.cbpa.2010.06.101
4. Dynamic transcriptomic profiles of zebrafish gills in response to zinc exposure C. Hogstrand, D. Zheng, P. Cunningham (King's College London, UK); P. Kille, G.P. Feeney (Cardiff University, UK); R.D. Handy (University of Plymouth, UK) Zinc is an essential micronutrient and an aquatic pollutant of concern. The fish gill is an important locus for zinc toxicity as well as for acclimation to elevated zinc. We exploited the tractability of the zebrafish gill to study time-dependent regulatory networks of geneexpression leading to zinc acclimation. Fish were exposed to zinc in water (260 μg L−1) and diet (2023 mg zinc kg−1) and compared to fish kept at control condition ([Zn(II)] water: 16 μg L−1, diet: 233 mg kg−1). Gill tissues were harvested at five time points up to 14 days and transcriptome changes analysed in quintuplicate with results anchored to physiological variables. In total, 525 genes were regulated (1.8 Fold-Change, 10% FDR) by zinc exposure. The number of regulated genes increased up to day seven and declined thereafter. Many genes displayed cyclic expression patterns, typical for homeostatic control mechanisms. Annotation enrichment analysis revealed strong overrepresentation of developmental genes and of transcription factors, such as steroid hormone receptors. Early regulation of genes was coordinated by a few key transcription factors and
followed by hedgehog and bone morphogenic protein signalling. The results suggest that zinc exposure reactivated developmental pathways in the gill and stimulated stem cell differentiation, a response likely reflecting gill remodelling in response to exposure. This provides insight to the mechanisms of zinc toxicity and acclimation as well as roles of zinc in biology. The study also highlights the importance of temporal transcriptomics analysis in order to resolve the discrete elements of biological processes, such as zinc acclimation. doi:10.1016/j.cbpa.2010.06.102
5. Effects of hexavalent chromium in Mytilus galloprovincialis L. Canesi, C. Barmo, R. Fabbri, S. Olivieri, G. Gallo (Dipartimento di Biologia, Università di Genova, Italy); L. Boatti, F. Dondero, A. Viarengo (University of Piemonte Orientale, DISAV, Italy) Hexavalent chromium Cr(VI) is an important contaminant released from both domestic and industrial effluents, representing the predominant chemical form in aquatic ecosystems. Cr(VI) is a model oxidative toxicant due to its intracellular reduction to the biologically active Cr(III) form and ROS production. Moreover, recent evidence suggests that chromium may interfere with the endocrine systems, in particular acting as a ‘metalloestrogen’. In this work, the effects of Cr(VI) were investigated in the marine bivalve Mytilus galloprovincialis. Mussels were exposed to Cr(VI) for 96 h (0.01–100 μg/animal/L) and different endpoints were evaluated in different tissues. The highest concentration induced severe stress conditions in the animals. At lower concentrations significant changes in lysosomal biomarkers in both hemocytes and digestive gland were observed. Cr(VI) also induced stimulation of antioxidant enzyme activities (catalase and GST) and lysosomal lipofuscin accumulation, indicating oxidative stress conditions. Moreover, changes in PES (Protein Expression Signature) in hemolymph serum, as evaluated by 2D electrophoresis were observed. Interestingly, in male digestive gland, Cr(VI) induced significant changes in the level of transcripts for Mytilus Estrogen Receptors (MeERs) and serotonin (5-HT) receptors, as evaluated by RT-Q-PCR, supporting the hypothesis that this metal may have significant endocrine disrupting properties in marine bivalves. The results demonstrate that environmental concentrations of Cr (VI) induce a wide range of responses in mussel tissues, with concentration-, tissue- and sex-related differential effects. Supported by the Italian Ministry of Research (PRIN2007) and by Fondazione CARIGE (prot. 2009.0659-42). doi:10.1016/j.cbpa.2010.06.103
6. Trace metals modulate gene expression and efflux activity of ABC transport proteins in the PLHC-1 fish cell line C. Della Torre (Department of Environmental Sciences, “G. Sarfatti” Università di Siena, Italy); R. Zaja, J. Loncar (Laboratory for Molecular Ecotoxicology, Division for Marine and Environmental Research, Ruđer Bošković Institute, Zagreb, Croatia); S. Focardi (Department of Environmental Sciences, “G. Sarfatti” Università di Siena, Italy); T. Smital (Laboratory for Molecular Ecotoxicology, Division for Marine and Environmental Research, Ruđer Bošković Institute, Zagreb, Croatia); I. Corsi (Department of Environmental Sciences, “G. Sarfatti” Università di Siena, Italy)