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:Propranolol is a beta-adrenergic receptor antagonist (β-blocker) that has been detected in United States wastewater effluents at concentrations ranging from 0.026 to 1.90 µg/l. In mammals, there is evidence that β-blockers can cause sexual dysfunction, and alter serotonergic pathways which may impact reproductive behavior but little is known about the effects on fish behavior. The present study tested the effects of propranolol on fecundity and on reproductive behavior of the fathead minnow, Pimephales promelas, a fish that exhibits male parental care. Sexually mature fathead minnows were housed at a ratio of one male and two females per tank and exposed to nominal concentrations of 0, 0.1, 1, 10 µg/l for 21 days. Measured concentrations (±SD) of propranolol were 0.05±0.02, 0.88±0.34 and 4.11±1.19 µg/l. There were no statistically significant differences in fecundity, fertilization rate, hatchability and time to hatch. Propranolol exposure was not associated with a change in nest rubbing behavior, time spent in the nest or approaching the females. There was a significant difference in the number of visits to the nest with males receiving low and medium propranolol treatments. The microarray analysis showed that there were 335 genes up-regulated and 400 genes down-regulated in the brain after exposure to the highest dose of propranolol. Among those genes, myoglobin and calsequestrin transcripts (fold change=10.84 and 5.49, respectively) were highly up-regulated. Ontological analyses indicated changes in genes involved in calcium ion transport, transcription, proteolysis and apoptosis/anti-apoptosis. The results showed that exposure to propranolol at concentrations as high as 4.11 µg/l did not significantly impact reproductive behavior or spawning abilities of fathead minnow but did alter the regulation of genes within the brain of fish. Effects of propanolol exposure were investigated in the brain of adult male fathead minnow exposed to 10 µg/L of propanolol or a solvent control solution (0.01% ethanol). For each treatment, the brain of four different fish were analyzed.