@article{pow_yost_aday_kullman_2016, title={Sharing the Roles: An Assessment of Japanese Medaka Estrogen Receptors in Vitellogenin Induction}, volume={50}, ISSN={["1520-5851"]}, DOI={10.1021/acs.est.6b01968}, abstractNote={Teleost fish express at least three estrogen receptor (ER) subtypes. To date, however, the individual role of these ER subtypes in regulating expression of estrogen responsive genes remains ambiguous. Here, we investigate putative roles of three ER subtypes in Japanese medaka (Oryzias latipes), using vitellogenin (VTG) I and II as model genes. We identify specific ligand/receptor/promoter dynamics, using transient transactivation assays that incorporate luciferase reporters comprising 3kb promoter/enhancer regions of medaka VTGI and VTGII genes. Four steroidal estrogens (17β-estradiol, estrone, estriol, and 17α-estradiol) were tested in these assays. Results indicate that all three medaka ERs (mERs) are capable of initiating transactivation of both VTG I and II, with ERβ2 exhibiting greatest activity. Promoter deletion analysis suggests that ligand-specific receptor transactivation and utilization of regional-specific estrogen response elements may be associated with differential activities of each medaka ER. Further, cluster analysis of in vivo gene expression and in vitro transactivation suggests that all three ER subtypes putatively play a role in up-regulation of VTG. Results illustrate that preferential ligand/receptor/promoter interactions may have direct implications for VTG gene expression and other ER-mediated regulatory functions that are relevant to the risk assessment of estrogenic compounds.}, number={16}, journal={ENVIRONMENTAL SCIENCE & TECHNOLOGY}, author={Pow, Crystal S. D. Lee and Yost, Erin E. and Aday, D. Derek and Kullman, Seth W.}, year={2016}, month={Aug}, pages={8886–8895} }
 @article{lee_kullman_yost_meyer_worley-davis_williams_reckhow_2015, title={Predicting characteristics of rainfall driven estrogen runoff and transport from swine AFO spray fields}, volume={532}, ISSN={["1879-1026"]}, DOI={10.1016/j.scitotenv.2015.06.051}, abstractNote={Animal feeding operations (AFOs) have been implicated as potentially major sources of estrogenic contaminants into the aquatic environment due to the relatively minimal treatment of waste and potential mobilization and transport of waste components from spray fields. In this study a Bayesian network (BN) model was developed to inform management decisions and better predict the transport and fate of natural steroidal estrogens from these sites. The developed BN model integrates processes of surface runoff and sediment loss with the modified universal soil loss equation (MUSLE) and the soil conservation service curve number (SCS-CN) runoff model. What-if scenario simulations of lagoon slurry wastes to the spray fields were conducted for the most abundant natural estrogen estrone (E1) observed in the system. It was found that E1 attenuated significantly after 2 months following waste slurry application in both spring and summer seasons, with the overall attenuation rate predicted to be higher in the summer compared to the spring. Using simulations of rainfall events in conjunction with waste slurry application rates, it was predicted that the magnitude of E1 runoff loss is significantly higher in the spring as compared to the summer months, primarily due to spray field crop management plans. Our what-if scenario analyses suggest that planting Bermuda grass in the spray fields is likely to reduce runoff losses of natural estrogens near the water bodies and ecosystems, as compared to planting of soybeans.}, journal={SCIENCE OF THE TOTAL ENVIRONMENT}, author={Lee, Boknam and Kullman, Sethw. and Yost, Erin E. and Meyer, Michael T. and Worley-Davis, Lynn and Williams, C. Michael and Reckhow, Kenneth H.}, year={2015}, month={Nov}, pages={571–580} }
 @article{yost_pow_hawkins_kullman_2014, title={Bridging the Gap From Screening Assays to Estrogenic Effects in Fish: Potential Roles of Multiple Estrogen Receptor Subtypes}, volume={48}, ISSN={["1520-5851"]}, DOI={10.1021/es404093n}, abstractNote={This study seeks to delineate the ligand interactions that drive biomarker induction in fish exposed to estrogenic pollutants and provide a case study on the capacity of human (h) estrogen receptor (ER)-based in vitro screening assays to predict estrogenic effects in aquatic species. Adult male Japanese medaka (Oryzias latipes) were exposed to solutions of singular steroidal estrogens or to the estrogenic extract of an anaerobic swine waste lagoon. All exposure concentrations were calibrated to be equipotent based on the yeast estrogen screen (YES), which reports activation of hERα. These exposures elicited significantly different magnitudes of hepatic vitellogenin and choriogenin gene induction in the male medaka. Effects of the same YES-calibrated solutions in the T47D-KBluc assay, which reports activation of hERα and hERβ, generally recapitulated observations in medaka. Using competitive ligand binding assays, it was found that the magnitude of vitellogenin/choriogenin induction by different estrogenic ligands correlated positively with preferential binding affinity for medaka ERβ subtypes, which are highly expressed in male medaka liver prior to estrogen exposure. Results support emerging evidence that ERβ subtypes are critically involved in the teleost estrogenic response, with the ERα:ERβ ratio being of particular importance. Accordingly, incorporation of multiple ER subtypes into estrogen screening protocols may increase predictive value for the risk assessment of aquatic systems, including complex estrogenic mixtures.}, number={9}, journal={ENVIRONMENTAL SCIENCE & TECHNOLOGY}, author={Yost, Erin E. and Pow, Crystal Lee and Hawkins, Mary Beth and Kullman, Seth W.}, year={2014}, month={May}, pages={5211–5219} }
 @article{yost_meyer_dietze_williams_worley-davis_lee_kullman_2014, title={Transport of Steroid Hormones, Phytoestrogens, and Estrogenic Activity across a Swine Lagoon/Sprayfield System}, volume={48}, ISSN={["1520-5851"]}, DOI={10.1021/es5025806}, abstractNote={The inflow, transformation, and attenuation of natural steroid hormones and phytoestrogens and estrogenic activity were assessed across the lagoon/sprayfield system of a prototypical commercial swine sow operation. Free and conjugated steroid hormones (estrogens, androgens, and progesterone) were detected in urine and feces of sows across reproductive stages, with progesterone being the most abundant steroid hormone. Excreta also contained phytoestrogens indicative of a soy-based diet, particularly, daidzein, genistein, and equol. During storage in barn pits and the anaerobic lagoon, conjugated hormones dissipated, and androgens and progesterone were attenuated. Estrone and equol persisted along the waste disposal route. Following application of lagoon slurry to agricultural soils, all analytes exhibited attenuation within 2 days. However, analytes including estrone, androstenedione, progesterone, and equol remained detectable in soil at 2 months postapplication. Estrogenic activity in the yeast estrogen screen and T47D-KBluc in vitro bioassays generally tracked well with analyte concentrations. Estrone was found to be the greatest contributor to estrogenic activity across all sample types. This investigation encompasses the most comprehensive suite of natural hormone and phytoestrogen analytes examined to date across a livestock lagoon/sprayfield and provides global insight into the fate of these analytes in this widely used waste management system.}, number={19}, journal={ENVIRONMENTAL SCIENCE & TECHNOLOGY}, author={Yost, Erin E. and Meyer, Michael T. and Dietze, Julie E. and Williams, C. Michael and Worley-Davis, Lynn and Lee, Boknam and Kullman, Seth W.}, year={2014}, month={Oct}, pages={11600–11609} }
 @article{yost_meyer_dietze_meissner_worley-davis_williams_lee_kullman_2013, title={Comprehensive Assessment of Hormones, Phytoestrogens, and Estrogenic Activity in an Anaerobic Swine Waste Lagoon}, volume={47}, ISSN={["1520-5851"]}, DOI={10.1021/es4026408}, abstractNote={In this study, the distribution of steroid hormones, phytoestrogens, and estrogenic activity was thoroughly characterized within the anaerobic waste lagoon of a typical commercial swine sow operation. Three independent rounds of sampling were conducted in June 2009, April 2010, and February 2011. Thirty-seven analytes in lagoon slurry and sludge were assessed using LC/MS-MS, and yeast estrogen screen was used to determine estrogenic activity. Of the hormone analytes, steroidal estrogens were more abundant than androgens or progesterone, with estrone being the predominant estrogen species. Conjugated hormones were detected only at low levels. The isoflavone metabolite equol was by far the predominant phytoestrogen species, with daidzein, genistein, formononetin, and coumestrol present at lower levels. Phytoestrogens were often more abundant than steroidal estrogens, but contributed minimally toward total estrogenic activity. Analytes were significantly elevated in the solid phases of the lagoon; although low observed log KOC values suggest enhanced solubility in the aqueous phase, perhaps due to dissolved or colloidal organic carbon. The association with the solid phase, as well as recalcitrance of analytes to anaerobic degradation, results in a markedly elevated load of analytes and estrogenic activity within lagoon sludge. Overall, findings emphasize the importance of adsorption and transformation processes in governing the fate of these compounds in lagoon waste, which is ultimately used for broadcast application as a fertilizer.}, number={23}, journal={ENVIRONMENTAL SCIENCE & TECHNOLOGY}, author={Yost, Erin E. and Meyer, Michael T. and Dietze, Julie E. and Meissner, Benjamin M. and Worley-Davis, Lynn and Williams, C. Michael and Lee, Boknam and Kullman, Seth W.}, year={2013}, month={Dec}, pages={13781–13790} }