Hexavalent chromium Cr(VI) is an important contaminant released from both domestic and industrial... more Hexavalent chromium Cr(VI) is an important contaminant released from both domestic and industrial effluents, and represents the predominant chemical form of the metal in aquatic ecosystems. In the marine bivalve Mytilus galloprovincialis exposure to non-toxic, environmentally relevant concentrations of Cr(VI) was shown to modulate functional parameters and gene expression in both the digestive gland and hemocytes. In this work, the effects of exposure to Cr(VI) (0.1-1-10 g L −1 animal −1 for 96 h) in mussel gills were investigated. Gill morphology and immunolocalization of GSH-transferase (GST), of components involved in cholinergic (AChE and ChAT), adrenergic (TH) and serotoninergic (5-HT 3 receptor) systems, regulating gill motility, were evaluated. Total glutathione content, activities of GSH-related enzymes (glutathione reductase -GSR, GST), of catalase, and of key glycolytic enzymes (phosphofructokinase -PFK and pyruvate kinase -PK) were determined. Moreover, mRNA expression of selected Mytilus genes (GST-, metallothionein isoforms MT10 and MT20, HSP70 and 5-HT receptor) was assessed by RT-q-PCR. Cr(VI) exposure induced progressive changes in gill morphology and in immunoreactivity to components involved in neurotransmission that were particularly evident at the highest concentration tested, and associated with large metal accumulation. Cr(VI) increased the activities of GST and GSR, and total glutathione content to a different extent at different metal concentrations, this suggesting Cr(VI) detoxication/reduction at the site of metal entry. Cr(VI) exposure also increased the activity of glycolytic enzymes, indicating modulation of carbohydrate metabolism. Significant changes in transcription of different genes were observed. In particular, the mRNA level for the 5-HTR was increased, whereas both decreases and increases were observed for GST-, MT10, MT20 and HSP70 mRNAs, showing sex-and concentration-related differences. The results demonstrate that Cr(VI) significantly affected functional and molecular parameters in mussel gills, and indicate that this tissue represents the major target of exposure to environmentally relevant concentrations of the metal.
Tunicates are chordate invertebrates, closely related to vertebrates, which represent valuable or... more Tunicates are chordate invertebrates, closely related to vertebrates, which represent valuable organisms for the study of a variety of biological processes from an evolutionary point of view. As invertebrates, they rely on innate immunity to cope with foreign, potentially pathogenic material. Among tunicates, the compound ascidian Botryllus schlosseri is emerging as a reliable model organism for the study of innate immune responses. However, there is a general lack of knowledge on the signalling pathways activated during immune responses and, in particular, in phagocytosis.
Hexavalent chromium Cr(VI) is an important contaminant released from both domestic and industrial... more Hexavalent chromium Cr(VI) is an important contaminant released from both domestic and industrial effluents, and represents the predominant chemical form of the metal in aquatic ecosystems. In the marine bivalve Mytilus galloprovincialis exposure to non-toxic, environmentally relevant concentrations of Cr(VI) was shown to modulate functional parameters and gene expression in both the digestive gland and hemocytes. In this work, the effects of exposure to Cr(VI) (0.1-1-10 g L −1 animal −1 for 96 h) in mussel gills were investigated. Gill morphology and immunolocalization of GSH-transferase (GST), of components involved in cholinergic (AChE and ChAT), adrenergic (TH) and serotoninergic (5-HT 3 receptor) systems, regulating gill motility, were evaluated. Total glutathione content, activities of GSH-related enzymes (glutathione reductase -GSR, GST), of catalase, and of key glycolytic enzymes (phosphofructokinase -PFK and pyruvate kinase -PK) were determined. Moreover, mRNA expression of selected Mytilus genes (GST-, metallothionein isoforms MT10 and MT20, HSP70 and 5-HT receptor) was assessed by RT-q-PCR. Cr(VI) exposure induced progressive changes in gill morphology and in immunoreactivity to components involved in neurotransmission that were particularly evident at the highest concentration tested, and associated with large metal accumulation. Cr(VI) increased the activities of GST and GSR, and total glutathione content to a different extent at different metal concentrations, this suggesting Cr(VI) detoxication/reduction at the site of metal entry. Cr(VI) exposure also increased the activity of glycolytic enzymes, indicating modulation of carbohydrate metabolism. Significant changes in transcription of different genes were observed. In particular, the mRNA level for the 5-HTR was increased, whereas both decreases and increases were observed for GST-, MT10, MT20 and HSP70 mRNAs, showing sex-and concentration-related differences. The results demonstrate that Cr(VI) significantly affected functional and molecular parameters in mussel gills, and indicate that this tissue represents the major target of exposure to environmentally relevant concentrations of the metal.
Tunicates are chordate invertebrates, closely related to vertebrates, which represent valuable or... more Tunicates are chordate invertebrates, closely related to vertebrates, which represent valuable organisms for the study of a variety of biological processes from an evolutionary point of view. As invertebrates, they rely on innate immunity to cope with foreign, potentially pathogenic material. Among tunicates, the compound ascidian Botryllus schlosseri is emerging as a reliable model organism for the study of innate immune responses. However, there is a general lack of knowledge on the signalling pathways activated during immune responses and, in particular, in phagocytosis.
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Papers by Laura Canesi