Project description:Despite major successes in reducing the risks of lead (Pb) exposure over the past few decades, two issues of considerable importance remain unresolved: (1) how differences in water chemistry influence acute and chronic Pb toxicity, and (2) the elucidation of specific toxic mechanisms and modes of action (MOA). To more clearly define the water chemistry parameters mediating Pb toxicity we evaluated the effects of hardness (as CaSO4) and DOC (as humic acid (HA)) during chronic (150d) exposures to the fathead minnow (Pimephales promelas). Traditional toxicological endpoints were examined alongside gene expression analyses to help clarify the underlying mechanisms and MOA of Pb toxicity and to identify robust molecular markers of exposure and effect. Keywords: time course, chronic lead (Pb) exposure
Project description:Omics approaches are broadly used to explore endocrine and toxicity-related pathways and functions. Nevertheless, there is still a significant gap in knowledge in terms of understanding the endocrine system and its numerous connections and intricate feedback loops, especially in non-model organisms. The fathead minnow (Pimephales promelas) is a widely used small fish model for aquatic toxicology and regulatory testing, particularly in North America. A draft genome has been published but the amount of available genomic or transcriptomic information is still far behind that of other more broadly studied species, such as the zebrafish. Here, we surveyed the tissue-specific proteome and transcriptome profiles in adult male fathead minnow. To do so, we generated a draft transcriptome using short and long sequencing reads. We also performed RNA sequencing and proteomics analysis on the telencephalon, hypothalamus, liver, and gut of male fish. The main purpose of this analysis was to generate tissue-specific omics data in order to support future aquatic ecotoxicogenomic and endocrine-related studies as well as to improve our understanding of the fathead minnow as an ecological model.
Project description:Characterization of the renal transcriptomic response to Yersinia ruckeri/Conseuqences of early life stage thyroid suppression on long-term immune function and the immune response in the fathead minnow (Pimephales promelas)
Project description:Despite major successes in reducing the risks of lead (Pb) exposure over the past few decades, two issues of considerable importance remain unresolved: (1) how differences in water chemistry influence acute and chronic Pb toxicity, and (2) the elucidation of specific toxic mechanisms and modes of action (MOA). To more clearly define the water chemistry parameters mediating Pb toxicity we evaluated the effects of hardness (as CaSO4) and DOC (as humic acid (HA)) during chronic (150d) exposures to the fathead minnow (Pimephales promelas). Traditional toxicological endpoints were examined alongside gene expression analyses to help clarify the underlying mechanisms and MOA of Pb toxicity and to identify robust molecular markers of exposure and effect. Keywords: time course, chronic lead (Pb) exposure To analyze the gene expression responses to low-level Pb exposures fish were exposed +/- Pb in low ionic strength base water and fish collected at 2d, 4d, 10d, and 30d for microarray analysis. Equal amounts of RNA from all no lead controls were pooled (18 fish total for 2d & 4d exposures; 12 fish total for 10d & 30d exposures) as reference samples for hybridization with each of 3 separate biological replicate pools (6 fish total for 2d & 4d exposures; 4 fish total for 10d & 30d exposures) of RNA from age-matched, lead-exposed fish. Each pair of hybridizations was repeated with dye-swaps. Additional repeats were performed for various arrays to ensure quality of data obtained from initial hybridization.
Project description:Production, usage and disposal of the munitions constituent (MC) cyclotrimethylenetrinitramine (RDX) has led to environmental releases on military facilities. The chemical attributes of RDX are conducive for leaching to surface water which may put aquatic organisms at risk of exposure. Because RDX has been observed to cause aberrant neuromuscular effects across a wide range of animal phyla, we assessed the effects of RDX on central nervous system (CNS) function in the representative aquatic ecotoxicological model species, fathead minnow (Pimephales promelas). A brain-tissue based cDNA library enriched for transcripts differentially expressed in response to RDX exposure was developed for fathead minnow and was transitioned to custom cDNA-based microarrays. All 4,128 cDNAs were sequenced, quality filtered and assembled yielding 3,018 unique sequences and 945 significant blastx matches (E ≤ 10-5). Bioassays were conducted exposing fathead minnows to RDX at 0.625, 1.25, 2.5, 5, 10 mg/L or an acetone-spike control for 10d. Overt toxicity of RDX in fathead minnow occurred only at the highest exposure concentration resulting in 50% mortality. Conversely, Bayesian analysis of microarray data indicated significant changes in transcript expression in fathead minnow brain tissue at RDX concentrations as low as 0.625 mg/L. In total, 154 microarray targets representing 44 unique transcript identities were differentially expressed in RDX exposures, the majority of which were validated by RT-qPCR. Investigation of molecular pathways, gene ontology and individual gene functions indicated that RDX exposures affected metabolic processes involved in: oxygen transport, neurological function, calcium binding / signaling, energy metabolism, cell cycle / cell proliferation, oxidative stress and ubiquitination. In total, our study indicated that RDX exposure affected molecular processes critical to CNS function in fathead minnow.