Project description:Diethylstilbestrol (DES) is a synthetic estrogen that has been banned for use in humans, but still is employed in livestock and aquaculture operations in some parts of the world. Detectable concentrations of DES in effluent and surface waters have been reported to range from slightly below 1 to greater than 10 ng/L. Little is known, however, concerning the toxicological potency of DES in fish. In this study, sexually-mature fathead minnows (Pimephales promelas) of both sexes were exposed to 1, 10 or 100 ng DES/L water in a flow-through system. Tissue concentrations of DES and changes in a number of estrogen-responsive endpoints, including alterations to the hepatic transcriptome in females, were measured in the fish at the end of a 4-d exposure, and after a 4-d depuration/recovery period in clean water. The objectives of the study were to measure accumulation of DES in fish tissues, characterize effects of the chemical on physiological endpoints related to reproductive performance, and to evaluate DES's potency relative to concentrations reported in aquatic environments. The current series includes n=11 microarrays associated with recovery-phase samples (collected from fish exposed continuously for 4 d, and then held in control water for an additional 4 days before tissues were collected).
Project description:Diethylstilbestrol (DES) is a synthetic estrogen that has been banned for use in humans, but still is employed in livestock and aquaculture operations in some parts of the world. Detectable concentrations of DES in effluent and surface waters have been reported to range from slightly below 1 to greater than 10 ng/L. Little is known, however, concerning the toxicological potency of DES in fish. In this study, sexually-mature fathead minnows (Pimephales promelas) of both sexes were exposed to 1, 10 or 100 ng DES/L water in a flow-through system. Tissue concentrations of DES and changes in a number of estrogen-responsive endpoints, including alterations to the hepatic transcriptome in females, were measured in the fish at the end of a 4-d exposure, and after a 4-d depuration/recovery period in clean water. The objectives of the study were to measure accumulation of DES in fish tissues, characterize effects of the chemical on physiological endpoints related to reproductive performance, and to evaluate DES's potency relative to concentrations reported in aquatic environments. The current series includes n=12 microarrays associated with exposure-phase samples (collected from fish exposed continuously for 4 d).
Project description:Diethylstilbestrol (DES) is a synthetic estrogen that has been banned for use in humans, but still is employed in livestock and aquaculture operations in some parts of the world. Detectable concentrations of DES in effluent and surface waters have been reported to range from slightly below 1 to greater than 10 ng/L. Little is known, however, concerning the toxicological potency of DES in fish. In this study, sexually-mature fathead minnows (Pimephales promelas) of both sexes were exposed to 1, 10 or 100 ng DES/L water in a flow-through system. Tissue concentrations of DES and changes in a number of estrogen-responsive endpoints, including alterations to the hepatic transcriptome in females, were measured in the fish at the end of a 4-d exposure, and after a 4-d depuration/recovery period in clean water. The objectives of the study were to measure accumulation of DES in fish tissues, characterize effects of the chemical on physiological endpoints related to reproductive performance, and to evaluate DES's potency relative to concentrations reported in aquatic environments. The current series includes n=11 microarrays associated with recovery-phase samples (collected from fish exposed continuously for 4 d, and then held in control water for an additional 4 days before tissues were collected). Fish were exposed to 0, 1, 10, or 100 ng DES/L delivered in a continuous flow (45 ml/min) of sand filtered, UV treated, Lake Superior Water, without the use of carrier solvents. Flow of DES into the test system was initiated without fish present and continued for 1 d. Exposures then were started by placing three male and three female sexually-mature fathead minnows into each tank. There were eight replicate tanks for the control and 100 ng/L treatments, and six replicate tanks for the 1 and 10 ng/L groups. The fish were held at 25+1M-BM-:C under a 16:8 L:D photoperiod and were fed frozen adult brine shrimp twice daily (San Francisco Bay Brand, Newark, CA, USA). Fish used for the experiment were from an on-site culture, and all procedures involving animals conformed to guidelines approved by the local Animal Care and Use Committee. After the 4-d exposure, fish from three tanks from each treatment (n=9 per sex) were sampled for determination of various biological endpoints. At this time fish from two additional tanks from the control and 100 ng/L treatments also were sampled for determination of DES tissue residues (n=6 per sex). Delivery of DES to the test system was subsequently stopped, and fish from the remaining three tanks per treatment group were sampled 4 d later (n= 9 per sex). The fathead minnows were euthanized with buffered MS-222 (Argent, Redmond, VA, USA) and weighed. Fish were scored for occurrence and relative expression of nuptial tubercles, which in males can be reduced by ER agonists. Blood was collected from the caudal vein/artery with a microhematocrit tube, and plasma was separated by centrifugation and stored at -80M-BM-:C. Gonads were removed from males and a subsample (8.5M-BM-13.0 mg; meanM-BM-1SD) was immediately immersed in tissue culture media for determination of ex vivo steroid production. Livers were removed from both sexes and flash-frozen for gene expression analyses using microarray (females) or real-time QPCR (males). Hepatic transcripts from three females per treatment group, in each phase of the experiment (except n=2 from recovery phase 10 ng/L) were analyzed using a custom 15,000 feature microarray (GEO Platform Accession GPL9248). Data sets for the exposure phase (n=12 microarrays) and recovery phase (n=11) were normalized independently using Fastlo (Ballman et al., 2004) implemented in R (http://www.r-project.org/), but analyzed using parallel approaches.
Project description:Diethylstilbestrol (DES) is a synthetic estrogen that has been banned for use in humans, but still is employed in livestock and aquaculture operations in some parts of the world. Detectable concentrations of DES in effluent and surface waters have been reported to range from slightly below 1 to greater than 10 ng/L. Little is known, however, concerning the toxicological potency of DES in fish. In this study, sexually-mature fathead minnows (Pimephales promelas) of both sexes were exposed to 1, 10 or 100 ng DES/L water in a flow-through system. Tissue concentrations of DES and changes in a number of estrogen-responsive endpoints, including alterations to the hepatic transcriptome in females, were measured in the fish at the end of a 4-d exposure, and after a 4-d depuration/recovery period in clean water. The objectives of the study were to measure accumulation of DES in fish tissues, characterize effects of the chemical on physiological endpoints related to reproductive performance, and to evaluate DES's potency relative to concentrations reported in aquatic environments. The current series includes n=12 microarrays associated with exposure-phase samples (collected from fish exposed continuously for 4 d). Fish were exposed to 0, 1, 10, or 100 ng DES/L delivered in a continuous flow (45 ml/min) of sand filtered, UV treated, Lake Superior Water, without the use of carrier solvents. Flow of DES into the test system was initiated without fish present and continued for 1 d. Exposures then were started by placing three male and three female sexually-mature fathead minnows into each tank. There were eight replicate tanks for the control and 100 ng/L treatments, and six replicate tanks for the 1 and 10 ng/L groups. The fish were held at 25+1M-BM-:C under a 16:8 L:D photoperiod and were fed frozen adult brine shrimp twice daily (San Francisco Bay Brand, Newark, CA, USA). Fish used for the experiment were from an on-site culture, and all procedures involving animals conformed to guidelines approved by the local Animal Care and Use Committee. After the 4-d exposure, fish from three tanks from each treatment (n=9 per sex) were sampled for determination of various biological endpoints. At this time fish from two additional tanks from the control and 100 ng/L treatments also were sampled for determination of DES tissue residues (n=6 per sex). Delivery of DES to the test system was subsequently stopped, and fish from the remaining three tanks per treatment group were sampled 4 d later (n= 9 per sex). The fathead minnows were euthanized with buffered MS-222 (Argent, Redmond, VA, USA) and weighed. Fish were scored for occurrence and relative expression of nuptial tubercles, which in males can be reduced by ER agonists. Blood was collected from the caudal vein/artery with a microhematocrit tube, and plasma was separated by centrifugation and stored at -80M-BM-:C. Gonads were removed from males and a subsample (8.5M-BM-13.0 mg; meanM-BM-1SD) was immediately immersed in tissue culture media for determination of ex vivo steroid production. Livers were removed from both sexes and flash-frozen for gene expression analyses using microarray (females) or real-time QPCR (males). Hepatic transcripts from three females per treatment group, in each phase of the experiment (except n=2 from recovery phase 10 ng/L) were analyzed using a custom 15,000 feature microarray (GEO Platform Accession GPL9248). Data sets for the exposure phase (n=12 microarrays) and recovery phase (n=11) were normalized independently using Fastlo (Ballman et al., 2004) implemented in R (http://www.r-project.org/), but analyzed using parallel approaches.
Project description:Ab initio gene prediction and evidence alignment were used to produce the first annotations for the fathead minnow (Pimephales promelas) genome. We also describe a genome browser, hosted by the Society of Environmental Toxicology and Chemistry, that provides simplified access to the annotation data in context with the genomic sequence. The present study extends the utility of the fathead minnow genome and supports the continued development of this species as a model organism for predictive toxicology. Environ Toxicol Chem 2017;36:3436-3442. Published 2017 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.
Project description:In 2011, the Fathead Minnow nidovirus (FHMNV; Genus Bafinivirus, Family Coronaviridae, Order Nidovirales) was isolated from pond-raised juvenile Muskellunge Esox masquinongy suffering from lingering mortality at the Wild Rose Hatchery in Wild Rose, Wisconsin. Moribund Muskellunge exhibited tubular necrosis in the kidneys as well as multifocal coalescing necrotizing hepatitis. The FHMNV was also isolated from apparently healthy juvenile Muskellunge at the Wolf Lake State Fish Hatchery in Mattawan, Michigan. The identity of the two syncytia-forming viruses (designated MUS-WR and MUS-WL from Wild Rose Hatchery and Wolf Lake State Fish Hatchery, respectively) as strains of FHMNV was determined based on multiple-gene sequencing and phylogenetic analyses. The pathogenicity of the MUS-WL FHMNV strain was determined by experimentally infecting naive juvenile Muskellunge through intraperitoneal injection with two viral concentrations (63 and 6.3 × 10(3) TCID50/fish). Both doses resulted in 100% mortality in experimentally infected fish, which exhibited severely pale gills and petechial hemorrhaging in eyes, fins, and skin. Histopathological alterations in experimentally infected fish were observed mainly in the hematopoietic tissues in the form of focal areas of necrosis. Phylogenetic analysis of concatenated partial spike glycoprotein and helicase gene sequences revealed differences between the MUS-WL FHMNV, MUS-WR FHMNV, and two other FHMNV originally isolated from moribund Fathead Minnows Pimephales promelas including the index FHMNV strain (GU002364). Based on a partial helicase gene sequence, a reverse transcriptase PCR assay was developed that is specific to FHMNV. These results give evidence that the risks posed to Muskellunge by FHMNV should be taken seriously. Received May 1, 2015; accepted February 8, 2016.
Project description:A growing number of studies have examined transcriptional responses to sex steroids along the hypothalamic-pituitary-gonadal axis in teleost fishes. However, data are lacking on the molecular cascades that underlie progesterone signaling. The objective of this study was to characterize the transcriptional response in the ovary of fathead minnows (Pimephales promelas) in response to progesterone (P4). Fathead minnow ovaries were exposed in vitro to 500 ng P4/L. Germinal vesicle migration and breakdown (GVBD) was observed and microarrays were used to identify gene cascades affected by P4. Microarray analysis identified 1702 differentially expressed transcripts after P4 treatment. Functional enrichment analysis revealed that transcripts involved in the molecular functions of protein serine/threonine kinase activity, ATP binding, and activity of calcium channels were increased after P4 treatment. There was an overwhelming decrease in levels of transcripts of genes that are structural constituents of ribosomes with P4 treatment. There was also evidence for gene expression changes in steroid and maturation-related transcripts. Pathway analyses identified cell cycle regulation, insulin action, hedgehog, and B cell activation as pathways containing an over-representation of highly regulated transcripts. Significant regulatory sub-networks of P4-mediated transcripts included genes regulated by tumor protein p53 and E2F transcription factor 1. These data provide novel insight into the molecular signaling cascades that underlie P4-signaling in the ovary and identify genes and processes that may indicate premature GVBD due to environmental pollutants that mimic progestins.
Project description:The US Environmental Protection Agency conducts ecological risk assessments with a battery of fish toxicity tests that include acute, early life stage, and reproduction tests. While endpoints in these tests (survival, growth and reproduction) are conceptually related, because they are measured in separate exposures, the quantitative relationships between them are difficult to determine and largely ignored. In the current test, fathead minnows (FHM) were exposed for 28 days to 1 mg/L or 2 mg/L carbaryl, a well-studied carbamate insecticide, in early life stages and then reared in clean water until adulthood, when reproduction was assessed. Also. weekly growth measurements were taken throughout the test to determine growth rates during and after exposure. Growth curves derived from these measurements were then compared to the reproductive output. The data indicate that carbaryl reduced growth rate only for a brief time early in the exposure. However, this brief effect impacted overall growth into adulthood and lowered the reproductive output of exposed FHM. The effect of a transient exposure early in life to carbaryl could have later population-level impacts by causing mortality, lowering growth rates, and reducing reproductive output.