Correlation of transcriptomic responses and metal bioaccumulation in Mytilus edulis L. reveals early indicators of stress
| Autor: | Robyn Hannigan, Helen C. Poynton, William E. Robinson, Bonnie J. Blalock |
|---|---|
| Rok vydání: | 2014 |
| Předmět: |
Gills
Microarray Mytilus edulis Health Toxicology and Mutagenesis Protein Array Analysis Aquatic Science Biology Bioinformatics Transcriptome Stress Physiological Gene expression Animals biology.organism_classification Mytilus Biochemistry Gene Expression Regulation Lead Metals Bioaccumulation Unfolded protein response Toxicogenomics Blue mussel Biomarkers Water Pollutants Chemical Cadmium Environmental Monitoring |
| Zdroj: | Aquatic toxicology (Amsterdam, Netherlands). 155 |
| ISSN: | 1879-1514 |
| Popis: | Marine biomonitoring programs in the U.S. and Europe have historically relied on monitoring tissue concentrations of bivalves to monitor contaminant levels and ecosystem health. By integrating 'omic methods with these tissue residue approaches we can uncover mechanistic insight to link tissue concentrations to potential toxic effects. In an effort to identify novel biomarkers and better understand the molecular toxicology of metal bioaccumulation in bivalves, we exposed the blue mussel, Mytilus edulis L., to sub-lethal concentrations (0.54 μM) of cadmium, lead, and a Cd+Pb mixture. Metal concentrations were measured in gill tissues at 1, 2, and 4 weeks, and increased linearly over the 4 week duration. In addition, there was evidence that Pb interfered with Cd uptake in the mixture treatment. Using a 3025 sequence microarray for M. edulis, we performed transcriptomic analysis, identifying 57 differentially expressed sequences. Hierarchical clustering of these sequences successfully distinguished the different treatment groups demonstrating that the expression profiles were reproducible among the treatments. Enrichment analysis of gene ontology terms identified several biological processes that were perturbed by the treatments, including nucleoside phosphate biosynthetic processes, mRNA metabolic processes, and response to stress. To identify transcripts whose expression level correlated with metal bioaccumulation, we performed Pearson correlation analysis. Several transcripts correlated with gill metal concentrations including mt10, mt20, and contig 48, an unknown transcript containing a wsc domain. In addition, three transcripts directly involved in the unfolded protein response (UPR) were induced in the metal treatments at 2 weeks and were further up-regulated at 4 weeks. Overall, correlation of tissue concentrations and gene expression responses indicates that as mussels accumulate higher concentrations of metals, initial stress responses are mobilized to protect tissues. However, given the role of UPR in apoptosis, it serves as an early indicator of stress, which once overwhelmed will result in adverse physiological effects. |
| Databáze: | OpenAIRE |
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