Contaminant biomonitoring augmented with a qPCR array indicates hepatic mRNA gene expression effects in...

Area of Science:

• Environmental Toxicology
• Wildlife Biology
• Molecular Ecology

Background:

• Birds bioaccumulate persistent contaminants, posing risks to embryos via maternal transfer.
• Assessing contaminant effects in wildlife is challenging due to limited sensitive biomarkers.
• Tissue residue concentrations alone have uncertainties in predicting adverse effects.

Purpose of the Study:

• To investigate the relationship between embryonic contaminant burdens and gene expression in liver tissue.
• To identify potential mRNA expression biomarkers for contaminant exposure in seabird embryos.
• To evaluate the utility of egg collection for biomonitoring contaminant impacts.

Main Methods:

• Collected rhinoceros auklet eggs and incubated them under controlled conditions.
• Analyzed whole embryo tissue for residues of mercury, pesticides, PFAS, PCBs, and HFRs.
• Extracted RNA from embryonic liver tissue for qPCR array analysis of gene expression.

Main Results:

• Found correlations between embryonic total mercury and specific genes, including sepp1.
• Identified a correlation between the biotransformation gene cyp1a4 and perfluoroalkyl carboxylic acid PFHpA.
• Demonstrated the link between chemical residues and in ovo mRNA gene expression in hepatic tissue.

Conclusions:

• Egg contaminant burdens are associated with specific molecular responses in developing seabird embryos.
• mRNA expression analysis in embryonic liver tissue can serve as a sensitive biomarker for contaminant effects.
• This approach enhances contaminant biomonitoring programs using samples from free-living populations.