Abstract:

To fully assess the impacts of Deepwater Horizon (DWH) oil on the vertebrate stress response and the trajectory for recovery, our research integrated molecular, cellular, gland/organ and whole animal physiological and behavioral studies using a benthic marine teleost, the Gulf toadfish (Opsanus beta), a resident of the Gulf of Mexico. These studies evaluated multiple pathways (e.g., pituitary fatigue, reduced receptor sensitivity, disruption or overstimulation of cortisol biosynthesis) and the consequence of these changes at the whole animal level (e.g., changes in carbohydrate metabolism, immune capacity and responses to natural stresses such as predation and social interaction). In this series of experiments, mRNA expression of CYP1A within the HPI axis (i.e., the hypothalamus-POA region, head kidney) as well as liver were evaluated during long-term exposures to DWH oil. The concentration of DWH oil sum total PAHs used in the experiment based on fluorescence analysis was Low 0.692 +/- 0.085, Medium 1.432 +/- 0.0116, and High 3.525 +/- 0.260 ug/L sum total PAHs and based on GC-MS(SIM)(US EPA Method 8270D) Low 0.041, Medium 0.158, and High 0.797 ug/L sum total PAHs. Each exposure was followed by a complementary recovery period (i.e., no oil or PAH exposure) to assess the recovery trajectory. These experiments were completed at Rosenstiel School of Marine and Atmospheric Science (RSMAS), University of Miami, Marine Technology & Life Sciences Seawater Complex (MTLSS) Building, room 211 between January 2019 to December 2019.

Suggested Citation:

Cartolano, Maria C., Matthew M. Alloy, Jenna Shroyer, and M. Danielle McDonald. 2020. Chronic exposure mRNA expression analysis on the Gulf toadfish (Opsanus beta). Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/n7-3kfs-jt63

Purpose:

To determine if the AhR was activated during a 28-day exposure to low, environmentally realistic concentrations of Deepwater Horizon (DWH) oil.

Data Parameters and Units:

The headers include Replicate fish ID; hypothalamus-POA EF1a mRNA expression (Ct value); hypothalamus-POA CYP1A mRNA expression (Ct value); head kidney EF1a mRNA expression (Ct value); head kidney CYP1A mRNA expression (Ct value); Liver EF1a mRNA expression (Ct value); liver CYP1A mRNA expression (Ct value) Note: nd= not determined

Methods:

Total RNA was isolated from tissues, DNAse treated, and cDNA synthesized. qPCR was then done on tissues to analyze mRNA expression of CYP1A compared to the housekeeping gene elongation factor 1 alpha.

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