The objectives of the present study were to determine 1) if temporal variability influenced the toxicity of Elkhorn River water and 2) if the toxic effect was consistent between two sentinel organisms, the fathead minnow (Pimephales promelas) and the northern leopard frog (Rana pipiens). During spring 2012, atrazine indicator strips were used to document the occurrence of agrichemical pulses in the Elkhorn River. Polar organic chemical integrative samplers (POCIS) were deployed for 14 d during both a pulse and post-pulse period as indicated by the atrazine strips. Pesticide concentrations detected in the POCIS extracts ranged from 1.6 to 281 fold higher during the pulse period compared to the post-pulse period. Fish and frog bioassays were conducted for 7 d, and hepatic mRNA expression of vitellogenin (Vtg) and estrogen receptor-α (ERα) was determined by quantitative real-time PCR (RT-qPCR). Compared to lab water controls, fish exposed to water collected during an agrichemical pulse experienced significant reductions in Vtg and ERα, whereas exposed female frogs did not. Male leopard frogs, in contrast experienced significant increases in the expression of ERα, whereas pulse exposed male minnows did not. The significant effects observed following agrichemical pulse exposure demonstrate 1) that episodic agrichemical runoff adversely impacts sentinel organisms, and 2) that the adverse impacts observed depends upon the sex and species of the sentinel organism.

Recent research has suggested that the fate of biologically active compounds (BACs) originating from point sources such as wastewater treatment plants is fundamentally different from that of similar compounds released from nonpoint sources through runoff from agricultural landscapes. Downstream from wastewater treatment plants, BACs will degrade via a variety of mechanisms; however, their concentration in the water adjacent to the point of discharge may not decrease over time, as the compounds are continually released. In contrast, in agricultural systems, BACs are episodically introduced to surface water during snowmelt and rainstorm events, and under these circumstances, may be found in water for only hours or days after a storm event. Recent research in our laboratories as well as others, has suggested that sediments play an important role in the persistence of herbicides and steroids in watersheds after nonpoint source loading events. Conceptually, the sediment serves as both a sink and a source, equilibrating with BACs during storm events then slowly releasing them back into the water over time, long after the initial pulse of chemicals has moved downstream.

The goal of the current study was to determine whether sediments from agriculturally-intense watersheds can act as a potential source of anti-estrogenic endocrine-disrupting compounds. The specific objectives of the current study were to determine 1) whether female fathead minnows (Pimephales promelas) experience alterations in endocrine function when exposed to sediments collected from agriculturally-intense watersheds and 2) if these sediments display anti-estrogenic activity in an in vitro assay. In addition, sediment samples were analyzed for the presence of steroid hormones and pesticides associated with local agricultural practices. To accomplish this, sediments and water were collected from three sites within two agriculturally-intense Nebraska watersheds (Bow Creek and the Elkhorn River). In 2009, minnows were exposed to sediment and/or water collected from the two Bow Creek sites (East Bow Creek and the Confluence) in the laboratory, while in 2010, minnows were exposed to sediment and/or water from East Bow Creek, the Confluence and the Elkhorn River. Following the 7-d exposure period, the hepatic mRNA expression of two-estrogen responsive genes, estrogen receptor α (ERα) and vitellogenin (Vtg) was determined. In 2009, females exposed to Confluence sediments, in the presence of laboratory water or Confluence water, experienced significant reductions in ERα expression relative to unexposed and Confluence water-exposed females. The defeminization of these females suggests the presence of a biologically-available anti-estrogenic compound in sediments collected from this site. In 2010, sediments were assessed for anti-estrogenic activity on days 0 and 7 of the exposure period using a four-hour yeast estrogen screen. Lipophilic extracts (LEs) of day 0 sediments collected from the Confluence and the Elkhorn River induced significant reductions in the estrogenic reporter activity of treated yeast cultures suggesting the presence of a lipophilic anti-estrogenic compound in these extracts. Chemical analysis revealed the presence of a variety of steroid hormones, including those associated with the production of beef cattle (ie: β-trenbolone, α-zearalanol and α-zearalenol), in sediments indicating that compounds utilized by local beef cattle operations are capable of entering nearby watersheds. Overall, the results of this study indicate that an environmentally-relevant anti-estrogenic compound is present in sediments from agriculturally-intense watersheds and that this compound is bioavailable to fish. Furthermore, the presence of steroid hormones in sediments from these watersheds provides evidence indicating that steroids are capable of sorbing to sediments. Clearly, sediments are capable of acting as a source of endocrine-disrupting compounds in the aquatic environment.

Despite advances in combination antiretroviral therapy (cART), people living with HIV (PLWH) continue to experience gastrointestinal dysfunction. Infusions of anti-α4β7 monoclonal antibodies (mAbs) have been proposed to increase virologic control during simian immunodeficiency virus (SIV) infection in macaques with mixed results. Recent evidences suggested that therapeutic efficacy of vedolizumab (a humanized anti-α4β7 mAb), during inflammatory bowel diseases depends on microbiome composition, myeloid cell differentiation, and macrophage phenotype. We tested this hypothesis in SIV-infected, anti-α4β7 mAb-treated macaques and provide flow cytometric and microscopic evidence that anti-α4β7 administered to SIV-infected macaques increases the maturity of macrophage phenotypes typically lost in the small intestines during SIV disease progression. Further, this increase in mature macrophage phenotype was associated with tissue viral loads. These phenotypes were also associated with dysbiosis markers in the gut previously identified as predictors of HIV replication and immune activation in PLWH. These findings provide a novel model of anti-α4β7 efficacy offering new avenues for targeting pathogenic mucosal immune response during HIV/SIV infection.

The northern leopard frog Rana (Lithobates) pipiens is an important animal model, being used extensively in cancer, neurology, physiology, and biomechanical studies. R. pipiens is a native North American frog whose range extends from northern Canada to southwest United States, but over the past few decades its populations have declined significantly and is now considered uncommon in large portions of the United States and Canada. To aid in the study and conservation of R. pipiens, this paper describes the first R. pipiens transcriptome. The R. pipiens transcriptome was annotated using Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Eukaryotic Orthologous Groups (KOG). Differential expression analysis revealed universal and tissue specific genes, and endocrine-related genes were identified. Transcriptome assemblies and other sequence data are available for download.