Global transcriptomic profiling of microcystin-LR or -RR treated hepatocytes (HepaRG).

The canonical mode of action (MOA) of microcystins (MC) is the inhibition of protein phosphatases, but complete characterization of toxicity pathways is lacking. The existence of over 200 MC congeners complicates risk estimates worldwide. This work employed RNA-seq to provide an unbiased and comprehensive characterization of cellular targets and impacted cellular processes of hepatocytes exposed to either MC-LR or MC-RR congeners.

Multigene Biomarkers of Pyrethroid Exposure: Exploratory Experiments.

We describe initial development of microarray-based assays for detecting 4 pyrethroid pesticides (bifenthrin, cypermethrin, esfenvalerate, and permethrin) in water. To facilitate comparison of transcriptional responses with gross apical responses, we estimated concentration-mortality curves for these pyrethroids using flow-through exposures of newly hatched Daphnia magna, Pimephales promelas adults, and 24 h posthatch P. promelas.

Tools to minimize interlaboratory variability in vitellogenin gene expression monitoring programs.

The egg yolk precursor protein vitellogenin is widely used as a biomarker of estrogen exposure in male fish. However, standardized methodology is lacking and little is known regarding the reproducibility of results among laboratories using different equipment, reagents, protocols, and data analysis programs. To address this data gap we tested the reproducibility across laboratories to evaluate vitellogenin gene (vtg) expression and assessed the value of using a freely available software data analysis program.

Initial development of a multigene 'omics-based exposure biomarker for pyrethroid pesticides.

Omics technologies have long since promised to address a number of long standing issues related to environmental regulation. Despite considerable resource investment, there are few examples where these tools have been adopted by the regulatory community, which is in part due to a focus of most studies on discovery rather than assay development. The current work describes the initial development of an omics based assay using 48h Pimephales promelas (FHM) larvae for identifying aquatic exposures to pyrethroid pesticides.

A new approach for the laboratory culture of the fathead minnow, Pimephales promelas.

Fathead minnows are routinely cultured for use in aquatic toxicology studies. A new mass culture system described in the present study consisted of 6 stainless steel tanks, each containing 68 fish and 20 spawning substrates. Spawning results are compared with a previous system of 22 individual glass aquaria, which contained 16 fish and 4 spawning substrates per tank.

Assessing impacts of land-applied manure from concentrated animal feeding operations on fish populations and communities.

Concentrated animal feeding operation (CAFO) manure is a cost-effective fertilizer. In the Midwest, networks of subsurface tile-drains expedite transport of animal hormones and nutrients from land-applied CAFO manure to adjacent waterways. The objective of this study was to evaluate impacts of land-applied CAFO manure on fish populations and communities.

Effects of eutrophication on vitellogenin gene expression in male fathead minnows (Pimephales promelas) exposed to 17alpha-ethynylestradiol in field mesocosms.

This study evaluated the effect of aquatic secondary nutrient supply levels (nitrogen and phosphorus) on the subcellular response of adult male fathead minnows (Pimephales promelas) exposed to a single nominal concentration of 17alpha-ethynylestradiol (EE2), a potent synthetic estrogen, under quasi-natural field conditions. Outdoor mesocosms were maintained under low, medium, and high nutrient supply conditions as categorized by total phosphorus (TP) level (nominal 0.012, 0.

Responses of molecular indicators of exposure in mesocosms: common carp (Cyprinus carpio) exposed to the herbicides alachlor and atrazine.

Common carp (Cyprinus carpio) were treated in aquatic mesocosms with a single pulse of the herbicides atrazine or alachlor to study the bioavailability and biological activity of these herbicides using molecular indicators: Liver vitellogenin gene expression in male fish for estrogenic activity, liver cytochrome P4501A1 gene expression, and DNA damage in blood cells using the single-cell gel electrophoresis method. Both alachlor and atrazine showed dose-related increases in DNA strand breaks at environmentally relevant concentrations (<100 ppb). Gene expression indicators showed that neither herbicide had estrogenic activity in the carp, whereas atrazine at concentrations as low as 7 ppb induced cytochrome P4501A1.

17alpha-ethynylestradiol-induced vitellogenin gene transcription quantified in livers of adult males, larvae, and gills of fathead minnows (Pimephales promelas).

We have applied a method for quantifying relative levels of messenger RNA (mRNA) transcription to assess chemically induced gene expression in fathead minnows (Pimephales promelas). Synthetic oligonucleotides designed for the fathead minnow vitellogenin gene transcription product were used in a reverse transcription polymerase chain reaction (RT-PCR) protocol. This sensitive and rapid strategy detected vitellogenin gene transcription in livers of male fathead minnows exposed to concentrations as low as 2 ng/L of the endocrine-disrupting compound 17alpha-ethynylestradiol for 24 h.