You are here:
Multigene Biomarkers of Pyrethroid Exposure: Exploratory Experiments
Citation:
Kostich, M., D. Bencic, A. Batt, MaryJean See, R. Flick, D. Gordon, Jim Lazorchak, AND A. Biales. Multigene Biomarkers of Pyrethroid Exposure: Exploratory Experiments. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY. Society of Environmental Toxicology and Chemistry, Pensacola, FL, 38(11):2436-2466, (2019). https://doi.org/10.1002/etc.4552
Impact/Purpose:
Preliminary comparison of different approaches to microarray-based aquatic neurotoxicant detection with each other and with toxic concentrations in a range of species. Shows that multi-gene RNA profiling of whole larval fathead minnows provides similar sensitivity to that achieved with RNA profiling of dissected adult brains. Assay sensitivity is sufficient to protect about 70% of all species represented in the Ecotox database. Supports further exploration of this format as a low-cost, low sample volume assay for simultaneous screening for a broad range of toxicants and physiological perturbations.
Description:
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. Median lethal concentration (LC50) estimates were below most reported values, perhaps attributable to the use of flow‐through exposures or of measured rather than nominal concentrations. Microarray analysis of whole P. promelas larvae and brains from exposed P. promelas adults showed that assays using either tissue type can detect these pyrethroids at concentrations below LC50 values reported for between 72 and 96% of aquatic species, depending on the pesticide. These estimates are conservative because they correspond to the lowest concentrations tested. This suggests that the simpler and less expensive whole‐larval assay provides adequate sensitivity for screening contexts where acute aquatic lethality is observed, but the responsible agent is not known. Gene set analysis (GSA) highlighted several Gene Ontology (GO) terms consistent with known pyrethroid action, but the implications of other GO terms are less clear. Exploration of the sensitivity of results to changes in data processing suggests robustness of the detection assay results, but GSA results were sensitive to methodological variations.
