Effects of aquatic nitrate exposures in the Laboratory on brain transcriptome in fathead minnows

These RNA sequencing (RNA-seq) data were collected to better understand how exposure to environmentally relevant doses of nitrate affects the brain transcriptome in fathead minnows. Fish were exposed to nominal doses of 0, 2, 5, 10, 25, or 100 mg/L nitrate nitrogen (NO3-N), added to flow-through well water as sodium nitrate. Transcriptomic data were collected from three experiments that addressed different life stages and durations of nitrate exposure: 1) acute exposure of juvenile fathead minnows for four days, from 75 to 79 days post fertilization (dpf), immediately before sexual maturation was expected to occur; 2) chronic exposure of juvenile fathead minnows from fertilization (day 0) through 79 dpf; this window covers all developmental stages until the beginning of sexual maturation; and 3) acute exposure of reproductive male and female pairs through one spawning cycle. The adult exposure occurred after fish were observed for two spawning cycles in clean water to obtain baseline data on their reproductive cyclicity, fecundity, and fertility. After the exposures, fish were euthanized and dissected to collect whole brains. Brain RNA was extracted, sequenced, and analyzed to identify genes and gene pathways that were affected by nitrate to improve our understanding of how nitrate affects fish physiology. Additionally, RNA data were analyzed to identify possible genetic biomarkers of nitrate exposure. The life history and water quality data for these studies is released in a separate but linked data release.