Impacts of Hypersaline Acclimation on Chlorpyrifos Toxicity to Salmonids

摘要: Author(s): Maryoung, Lindley Anne | Advisor(s): Schlenk, Daniel Abstract: As part of their unique life cycle, most Pacific salmonids transition from freshwater to saltwater, requiring various adjustments in physiology. However, molecular mechanisms underlying this are largely unknown. Additionally, acclimation hypersaline conditions enhances the acute toxicity certain thioether organophosphate and carbamate pesticides some species euryhaline fish, yet sublethal impacts have been far less studied. The current study aimed determine salmonid smoltification, as well how a common pesticide, chlorpyrifos (CPF). A transcriptomics approach was used assess differential gene expression coho salmon (Oncorhynchus kisutch) liver, gills, olfactory rosettes after salinity found that majority altered genes were tissue concentration dependent. From few shared genes, potential osmosenor identified. Osmotic signal transduction cascades also impacted three tissues. Salinity then coupled with CPF on toxicity. Time death rainbow trout mykiss) by more rapid than water (16 ppth). did not impact metabolism, precipitation, or acetylcholinesterase inhibition CPF. In contrast, mRNA neurological targets upregulated saltwater acclimated consistent diminished neuronal signaling which may protect fish cholinergic overload associated inhibition. Sublethal experiments, environmentally relevant, conducted olfaction. Combined exposure olfaction at molecular, physiological, behavioral levels. Concurrent hypersalinity 0.5 µg/L four inhibit transduction. At physiological level, caused decrease sensory response amino acid L-serine bile salt taurocholic acid. negatively behavior reduced avoidance predator cue (L-serine). Overall, these results will be very useful risk assessment strategies evaluating compounds nature estuarine environments stress rising sea