@article{leonard_cope_hammer_barnhart_bringolf_2017, title={Extending the toxicity-testing paradigm for freshwater mussels: Assessing chronic reproductive effects of the synthetic estrogen 17 alpha-ethinylestradiol on the unionid mussel Elliptio complanata}, volume={191}, ISSN={["1878-1659"]}, DOI={10.1016/j.cbpc.2016.09.002}, abstractNote={Surface water concentrations of the synthetic estrogen 17α-ethinylestradiol (EE2) as low as 1ng/L can cause adverse reproductive effects in fish under acute and chronic exposure conditions, whereas higher concentrations (> 5ng/L) in acute studies are necessary to elicit adverse effects in freshwater mussels. Prolonged chronic exposures of freshwater mussels to EE2 remain un-evaluated. An extended duration testing paradigm was used to examine reproductive and biochemical (carbohydrate, lipid, protein) effects of EE2 on the unionid mussel, Elliptio complanata, throughout its reproductive cycle. Mussels were exposed to a control and EE2 concentrations (5 and 50ng/L) in six discrete and sequential 28 d tests, and in one discrete and simultaneous 180 d test, from February through August. Foot protrusion and siphoning behavior were recorded daily, along with conglutinate releases and larval (glochidia) mortality. Gonad, hemolymph, and gonad fluid samples were taken for biochemical and vitellogenin-like protein (Vtg) analysis post-exposure. Female mussels released eggs and conglutinates during the months of April to June, indicating sexual maturation during this time. Conglutinates released in the 5ng/L treatment in 28 d exposures contained fewer glochidia and more eggs, and increased concentrations of Vtg in hemolymph were observed from April to August in the 5ng/L treatment during the 180 d exposure. Results indicate that the 180 d test approach, concurrent with the sequence of 28 d tests, enabled a more robust evaluation of mussel behavior and physiology than would have been possible with a single short-term (28 d) test.}, journal={COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY C-TOXICOLOGY & PHARMACOLOGY}, author={Leonard, Jeremy A. and Cope, W. Gregory and Hammer, Edward J. and Barnhart, M. Christopher and Bringolf, Robert B.}, year={2017}, month={Jan}, pages={14–25} }
 @article{archambault_bergeron_cope_lazaro_leonard_shea_2016, title={Assessing toxicity of contaminants in riverine suspended sediments to freshwater mussels}, volume={36}, ISSN={0730-7268}, url={http://dx.doi.org/10.1002/etc.3540}, DOI={10.1002/etc.3540}, abstractNote={The Clinch River in Virginia and Tennessee, USA, is well known for its diverse native freshwater mussel assemblages; however, notable declines in mussel populations in recent decades have prompted much concern and subsequent research. The authors examined the toxicity of recently deposited sediments on juveniles of the freshwater mussel Epioblasma brevidens by collecting time-integrated sediment samples from the water column with sediment traps from 11 sites in the Clinch River basin, including 6 sites within an 88-km reach deemed a "mussel zone of decline." Mussels were exposed to the riverine sediments and to 3 control sediments for 28 d; survival, shell length, and biomass were then assessed. Sediment treatment (i.e., river location) had a significant effect on mussel survival (p < 0.01) and biomass (p = 0.02) but did not affect length (p = 0.37), and sediments from 2 of the tributaries were the most toxic. Inorganic and organic analyses of sediments indicated the presence of metals and polycyclic aromatic hydrocarbons at all sites. Manganese was negatively correlated with mussel survival and biomass, as was ammonia with survival and total organic carbon with biomass. Current land uses in the watershed indicate that fossil fuel mining and agriculture may be associated with elevated manganese and ammonia, respectively. The authors found that sediments collected with sediment traps over relatively short deployment durations can help elucidate recent contaminant influx and its potential for inducing toxicity in benthic organisms. Environ Toxicol Chem 2017;36:395-407. © 2016 SETAC.}, number={2}, journal={Environmental Toxicology and Chemistry}, publisher={Wiley}, author={Archambault, Jennifer M. and Bergeron, Christine M. and Cope, W. Gregory and Lazaro, Peter R. and Leonard, Jeremy A. and Shea, Damian}, year={2016}, month={Aug}, pages={395–407} }
 @article{leonard_cope_barnhart_bringolf_2014, title={Metabolomic, behavioral, and reproductive effects of the aromatase inhibitor fadrozole hydrochloride on the unionid mussel Lampsilis fasciola}, volume={206}, ISSN={["1095-6840"]}, DOI={10.1016/j.ygcen.2014.07.019}, abstractNote={• We examined the effects of a model aromatase inhibitor on a unionid mussel. • Endpoints of interest included female reproduction, adult behavior, and metabolism. • Significant reduction of female lure display occurred at mid-level concentrations. • Female metabolites were adversely affected at the lowest tested concentration. • Alterations of metabolites in both sexes were reduced after prolonged exposure. Androgen-induced masculinization of female aquatic biota poses concerns for natural population stability. This research evaluated the effects of a twelve day exposure of fadrozole hydrochloride on the metabolism and reproductive status of the unionid mussel Lampsilis fasciola . Although this compound is not considered to be widespread in the aquatic environment, it was selected as a model aromatase (enzyme that converts testosterone to estradiol) inhibitor. Adult mussels were exposed to a control and 3 concentrations of fadrozole (2 μg/L, 20 μg/L, and 50 μg/L), and samples of gill tissue were taken on days 4 and 12 for metabolomics analysis. Gills were used because of the variety of critical processes they mediate, such as feeding, ion exchange, and siphoning. Daily observed mussel behavior included female mantle display, foot protrusion, siphoning, and larval (glochidia) releases. Glochidia mortality was significantly higher in the 20 μg/L treatment. Fewer conglutinate (packets of glochidia) releases were observed in the 50 μg/L treatment, and mortality was highly correlated to release numbers. Foot protrusion was significantly higher in females in nearly all treatments, including the control, during the first 4 days of observations. However, this sex difference was observed only in the 50 μg/L treatment during the last 8 days. Generally, metabolites were significantly altered in female gill tissue in the 2 μg/L treatment whereas males were mostly affected only at the highest (50 μg/L) treatment. Both sexes also revealed significant reductions in fadrozole-induced metabolic effects in gill tissue sampled after 12 days compared to tissue sampled after 4 days, indicating time-dependent mechanisms of disruptions in metabolic pathways and homeostatic processes to compensate for such disruptions.}, journal={GENERAL AND COMPARATIVE ENDOCRINOLOGY}, author={Leonard, Jeremy A. and Cope, W. Gregory and Barnhart, M. Christopher and Bringolf, Robert B.}, year={2014}, month={Sep}, pages={213–226} }
 @article{leonard_cope_barnhart_bringolf_2014, title={Metabolomic, behavioral, and reproductive effects of the synthetic estrogen 17 alpha-ethinylestradiol on the unionid mussel Lampsilis fasciola}, volume={150}, ISSN={["1879-1514"]}, DOI={10.1016/j.aquatox.2014.03.004}, abstractNote={The endocrine disrupting effects of estrogenic compounds in surface waters on fish, such as feminization of males and altered sex ratios, may also occur in aquatic invertebrates. However, the underlying mechanisms of action and toxicity, especially in native freshwater mussels (Order Unionoida), remain undefined. This study evaluated the effects of a 12-day exposure of 17 α-ethinylestradiol (EE2), a synthetic estrogen in oral contraceptives commonly found in surface waters, on the behavior, condition, metabolism, and reproductive status of Lampsilis fasciola. Adult mussels of both sexes were exposed to a control and two concentrations of EE2 (0 ng/L, 5 ng/L considered to be environmentally relevant, and 1,000 ng/L designed to provide a positive metabolic response), and samples of gill tissue were taken on days 4 and 12; gills were used because of the variety of critical processes they mediate, such as feeding, ion exchange, and siphoning. Observations of mussel behavior (mantle display, siphoning, and foot movement) were made daily, and condition of conglutinates (packets of eggs and/or glochidia) released by females was examined. No significant effects of EE2 on glochidia mortality, conglutinate condition, female marsupial gill condition, or mussel foot extension were observed. However, exposure to both concentrations of EE2 significantly reduced male siphoning and mantle display behavior of females. Metabolomics analyses identified 207 known biochemicals in mussel gill tissue and showed that environmentally relevant EE2 concentrations led to decreases in glycogen metabolism end products, glucose, and several essential fatty acids in females after 12 days, indicating reductions in energy reserves that could otherwise be used for growth or reproduction. Moreover, males and females showed significant alterations in metabolites involved in signal transduction, immune response, and neuromodulation. Most of these changes were apparent at 1,000 ng/L EE2, but similar metabolites and pathways were also affected at 5 ng/L EE2. Components of the extracellular matrix of gill tissue were also altered. These results demonstrate the utility of metabolomics when used in conjunction with traditional physiological and behavioral toxicity test endpoints and establish the usefulness of this approach in determining possible underlying toxicological mechanisms of EE2 in exposed freshwater mussels.}, journal={AQUATIC TOXICOLOGY}, author={Leonard, Jeremy A. and Cope, W. Gregory and Barnhart, M. Christopher and Bringolf, Robert B.}, year={2014}, month={May}, pages={103–116} }