Project description:Our main objectives were: 1) to identify transcriptional signatures specific to the exposure to two metals: Ni and Cd; 2) to investigate the mechanisms of toxicity for these two metals; and 3) to develop a predictive tool to identify the sublethal effects of Ni and Cd contaminants in fish sampled from natural environments. The molecular mechanisms underlying nickel (Ni) and cadmium (Cd) toxicity and their specific effects on fish are poorly understood. Documenting gene transcription profiles offers a powerful approach towards identifying the molecular mechanisms affected by these metals and to discover biomarkers of their toxicity. However, confounding environmental factors can complicate the interpretation of the results and the detection of biomarkers for fish captured in their natural environment. In the present study, a 1000 candidate-gene microarray, developed from a previous RNA-seq study on a subset of individual fish from contrasting level of metal contamination, was used to investigate the transcriptional response to metal (Ni and Cd) and non metal (temperature, oxygen, and diet) stressors in yellow perch (Perca flavescens). Specifically, we aimed at 1) identifying transcriptional signatures specific to Ni and Cd exposure, 2) investigating the mechanisms of their toxicity, and 3) developing a predictive tool to identify the sublethal effects of Ni and Cd contaminants in fish sampled from natural environments. A total of 479 genes displayed significantly different transcription levels when temperature varied while 287 and 177 genes were differentially transcribed at different concentrations of Ni and Cd, respectively. These metals were found to mainly affect the transcription level of genes involved in iron metabolism, transcriptional and translational processes, vitamin metabolism, blood coagulation, and calcium transport. In addition, a linear discriminant analysis (LDA) made using gene transcription levels yielded 94% correctly reassigned samples regarding their level of metal contamination, which indicates the potential of the microarray to detect perch response to Cd or Ni effects.

Project description:Transcriptional profiling of the digestive gland tissue of female mussel Mytilus galloprovincialis exposed to nickel along with a temperature gradient Background: The exposure of marine organisms to stressing agents may affect the level and pattern of gene expression. Although many studies have examined the ecological effects of heat stress on mussels, little is known about the physiological mechanisms that might be affected by co-exposure to heat stress and environmental contaminants such as nickel (Ni). In the present work we investigated the effects of simultaneous changes in temperature and Ni supply on lysosomal membrane stability (LMS) and malondialdehyde accumulation (MDA) in the digestive gland (DG) of the blue mussel Mytilus galloprovincialis (Lam.). To shed some light into how the molecular response to environmental stressors is modulated, we employed a cDNA microarray with 1,673 sequences to measure the relative transcript abundances in the DG of mussels exposed to Ni along with the temperature increase. Temperature and Ni rendered additive effects on LMS and MDA accumulation, increasing the toxic effects of metal cations. Ni loads in DG tissues was also affected by co-exposure to 26°C. In animals exposed only to heat stress, functional genomics analysis of the microarray data (171 DEGs) revealed 7 biological processes, largely dominated by the up-regulation of folding protein-related genes, and the down regulation of genes involved in cell migration and cellular component assembly. Exposure to Ni at 18°C and 26°C rendered respectively 188 and 262 DEGs showing distinct pattern in term of biological processes. In particular, the response of mussels exposed to Ni at 26°C was characterized by the up regulation of proteolysis, ribosome biogenesis, response to unfolded proteins and catabolic-related genes as well as the down-regulation of genes encoding cellular metabolic processes. Our data provide new insights on the transcriptomic response in mussels challenging temperature increases and Ni exposure and should be carefully considered in view of the biological effects of heat stress and particularly in polluted areas.

Project description:Our main objectives were: 1) to identify transcriptional signatures specific to the exposure to two metals: Ni and Cd; 2) to investigate the mechanisms of toxicity for these two metals; and 3) to develop a predictive tool to identify the sublethal effects of Ni and Cd contaminants in fish sampled from natural environments. The molecular mechanisms underlying nickel (Ni) and cadmium (Cd) toxicity and their specific effects on fish are poorly understood. Documenting gene transcription profiles offers a powerful approach towards identifying the molecular mechanisms affected by these metals and to discover biomarkers of their toxicity. However, confounding environmental factors can complicate the interpretation of the results and the detection of biomarkers for fish captured in their natural environment. In the present study, a 1000 candidate-gene microarray, developed from a previous RNA-seq study on a subset of individual fish from contrasting level of metal contamination, was used to investigate the transcriptional response to metal (Ni and Cd) and non metal (temperature, oxygen, and diet) stressors in yellow perch (Perca flavescens). Specifically, we aimed at 1) identifying transcriptional signatures specific to Ni and Cd exposure, 2) investigating the mechanisms of their toxicity, and 3) developing a predictive tool to identify the sublethal effects of Ni and Cd contaminants in fish sampled from natural environments. A total of 479 genes displayed significantly different transcription levels when temperature varied while 287 and 177 genes were differentially transcribed at different concentrations of Ni and Cd, respectively. These metals were found to mainly affect the transcription level of genes involved in iron metabolism, transcriptional and translational processes, vitamin metabolism, blood coagulation, and calcium transport. In addition, a linear discriminant analysis (LDA) made using gene transcription levels yielded 94% correctly reassigned samples regarding their level of metal contamination, which indicates the potential of the microarray to detect perch response to Cd or Ni effects. Comparison between fish exposed to three temperatures (11, 20, 28M-BM-0C) using a loop design, comparison between control fish and fich exposed to restrictive diet using a pairwise design, comparison between fish exposed to hypoxia and control fish, comparison between fish exposed to two concentrations of cadmium and control fish using a loop design, and comparison between fish exposed to two concentrations of nickel and control fish using a loop design.

Dataset Information

Transcriptome analysis of the early response to nickel (Ni) in Acidiphilium sp. PM

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