Gene Expression of Fathead Minnows (Pimephales promelas) Exposed to Two Types of Treated Municipal Wastewater Effluents

Abstract

Contaminants of emerging concern (CECs) in treated municipal effluents have the potential to adversely impact exposed organisms prompting elevated public concern. Using transcriptomic tools, we investigated changes in gene expression and cellular pathways in the liver of male fathead minnows (Pimephales promelas) exposed to 5% concentrations of full secondary-treated (HTP) or advanced primary-treated (PL) municipal wastewater effluents containing CECs. Gene expression changes were associated with apical end points (plasma vitellogenin and changes in secondary sexual characteristics). Of 32 effluent CECs analyzed, 28 were detected including pharmaceuticals, personal care products, hormones, and industrial compounds. Exposure to both effluents produced significantly higher levels of plasma VTG and changes in secondary sexual characteristics (e.g., ovipositor development). Transcript patterns differed between effluents, with <10% agreement in the detected response (e.g., altered production of transcripts involved in xenobiotic detoxification, oxidative stress, and apoptosis were observed following exposure to both effluents). Exposure to PL effluent caused changes in transcription of genes involved in metabolic pathways (e.g., lipid transport and steroid metabolism). Exposure to HTP effluent affected transcripts involved in signaling pathways (e.g., focal adhesion assembly and extracellular matrix). The results suggest a potential association between some transcriptomic changes and physiological responses following effluent exposure. This study identified responses in pathways not previously implicated in exposure to complex chemical mixtures containing CECs, which are consistent with effluent exposure (e.g., oxidative stress) in addition to other pathway responses specific to the effluent type.

Using Transcriptomic Tools to Evaluate Biological Effects Across Effluent Gradients at a Diverse Set of Study Sites in Minnesota, USA

“…Of these, 10 from each were found in the CRP, suggesting a similar pattern of gene regulation. The remainder of the genes either are unique to downstream (9) or effluent (7) or were found in both but with opposite gene regulation (8). This was a common trend throughout many of the significant KEGG pathways identified at the R site.…”

Transcriptomic Profiles in Zebrafish Liver Permit the Discrimination of Surface Water with Pollution Gradient and Different Discharges

“…Although the concentrations of these chemicals employed in the zebrafish exposure research were higher than detected concentrations in the river water, many other compounds coexisted in the surface water, which affected aquatic vertebrate in similar mode with these typical pollutants. Hence, it is reasonable to compare the gene profiles in the zebrafish exposed to single compound and those exposed to the surface water [8]. These model chemicals were selected because of the typical chemical structure, toxic mechanism, as well as the data availability.…”

“…We are facing many challenges in understanding the big data obtained using this powerful tool, while researchers have successfully made some progresses to use genomic profiles of aquatic organisms exposed to wastewater effluent [8,9,10,11,12] and surface water [13,14]. Falciani et al [15] used gene expression fingerprints to distinguish the origins of flounder taken from sites of different pollution status.…”

A Self‐Organizing Map of the Fathead Minnow Liver Transcriptome to Identify Consistent Toxicogenomic Patterns across Chemical Fingerprints

“…The result of this clustering step confirmed the visual observations for the toxicogenomic fingerprints just described. 2013) were assigned to cluster 7 together with other experiments from 5 different studies that obviously showed only small effects on the fathead minnow liver transcriptome (Garcia-Reyero et al 2009, 2011Carter 2010;Gust et al 2011;Vidal-Dorsch et al 2013).…”