Project description: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 help link tissue concentrations to 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 M) 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.
Project description: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 M-bM-^@M-^Xomic methods with these tissue residue approaches we can uncover mechanistic insight to help link tissue concentrations to 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 M-oM-^AM--M) 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. A total of 52 samples including initial samples and 3 time-points following exposure to cadmium, lead, or a mixture. There were four replicate samples for each treatment and time-point. An additional three replicate samples were used for RT-qPCR.
Project description:Background biology: Global warming has accelerated in recent decades, with the Arctic warming 2–3 times faster than the global average. As a result boreal species are expanding into the Arctic, at a pace reflecting environmental warming. Nevertheless, the poleward expansion of boreal marine species is restricted by their ability to tolerate low water temperatures, and in the case of intertidal species, sub-zero air temperatures during winter. In Greenland, however, the number of days with extreme sub-zero air temperatures has decreased by more than 50% since the 1950’s, suggesting that the low air temperature constraint is weakening. Although boreal intertidal species could potentially benefit from this warmer climate to establish populations in the Arctic, recent work has shown that local intertidal summer air temperatures in Greenland can exceed 36°C. This temperature is above the thermoregulatory capacity of many boreal intertidal species, including the highly abundant blue mussel Mytilus edulis. Therefore will further colonisation of M. edulis in Greenland be inhibited by the increasingly warm summer temperatures. Aim of experiment: Intertidal animals (Greenland blue mussel M. edulis) were sampled in situ on the first warm days of the year from the inner (warmer) and outer (cooler) regions of the Godthåbsfjorden around Nuuk (64°N) to examine the fjord temperature gradient effect. In addition, subtidal M. edulis were also collected and subjected to two acute temperature shocks of 22 and 32°C, which represented common and extreme summer air temperatures for intertidal habitats near Nuuk.
Project description:Blue mussel larvae were fed, in a first group, a balanced diet of essential fatty acids (EFAs) provided by a cocktail diet (COC) from three algal species. Larvae were cultured in three separate tanks from hatching, 0 day post-fertilization (DPF) until 42 DPF. Treated larvae were fed a deficient diet (Tiso) that contains low levels of arachidonic acid (AA) and eicosapentaenoic acid (EPA), two EFAs necessary for larval development, performance, and survival. The goal is to identify coordinated patterns of gene expression and understand their predictive function in relation to growth and mortality during early developmental stages of the blue mussel Mytilus edulis. In order to understand the mechanisms by which growth and survival drive an organism to the full range of its adaptation, we de novo assembled of the mussel transcriptome during early development using next-generation sequencing (NGS) technology, then designed customized microarrays targeting every developmental stage, which encompass major transitions in tissue organization of the fast-evolved blue mussel
Project description:Blue mussel larvae were fed, in a first group, a balanced diet of essential fatty acids (EFAs) provided by a cocktail diet (COC) from three algal species. Larvae were cultured in three separate tanks from hatching, 0 day post-fertilization (DPF) until 42 DPF. Treated larvae were fed a deficient diet (Tiso) that contains low levels of arachidonic acid (AA) and eicosapentaenoic acid (EPA), two EFAs necessary for larval development, performance, and survival. The goal is to identify coordinated patterns of gene expression and understand their predictive function in relation to growth and mortality during early developmental stages of the blue mussel Mytilus edulis. In order to understand the mechanisms by which growth and survival drive an organism to the full range of its adaptation, we de novo assembled of the mussel transcriptome during early development using next-generation sequencing (NGS) technology, then designed customized microarrays targeting every developmental stage, which encompass major transitions in tissue organization of the fast-evolved blue mussel Two experimental conditions, COC and Tiso diets. Biological replicates 3 culture replicate per stage of development for 5 stages of development. Eggs and trocophore larvae did not undertake treatments