Hepatic Gene Expression Profiling of American Kestrels (Falco sparverius) Exposed In Ovo to Three Alternative Brominated Flame Retardants.

A number of brominated flame retardants (BFRs) have been reported to interfere with the thyroid signaling pathway and cause oxidative stress in birds, yet the underlying shifts in gene expression associated with these effects remain poorly understood. In this study, we measured hepatic transcriptional responses of 31 genes in American kestrel (Falco sparverius) hatchlings following in ovo exposure to one of three high-volume alternative BFRs: 1,2-bis(2,4,6-tribromophenoxy) ethane (BTPBE), bis(2-ethylhexyl)-2,3,4,5-tetrabromophthalate (TBPH), or 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (EHTBB). Hatchling kestrels exhibited shifts in the expression of genes related to oxidative stress (CYP, GSTA, SOD, and GPX1), thyroid hormone metabolism and transport (DIO1, DIO2, and TTR), lipid and protein metabolism (PPAR, HMGCR, FAB1, and LPL), and cytokine-mediated inflammation (TLR3, IL18, IRF7, STAT3, RACK1, and CEBPB). Male and female hatchlings differed in which genes were differentially expressed, as well as the direction of the effect (up- vs. downregulation). These results build upon our previous findings of increased oxidative stress and disrupted thyroid signaling pathway in the same hatchlings. Furthermore, our results indicate that inflammatory responses appear to occur in female hatchlings exposed to BTBPE and EHTBB in ovo. Gene expression analysis revealed multiple affected pathways, adding to the growing evidence that sublethal physiological effects are complex and are a concern for birds exposed to BTBPE, EHTBB, or TBPH in ovo.

Reconnaissance of Surface Water Estrogenicity and the Prevalence of Intersex in Smallmouth Bass (Micropterus Dolomieu) Inhabiting New Jersey.

The observation of testicular oocytes in male fishes has been utilized as a biomarker of estrogenic endocrine disruption. A reconnaissance project led in the Northeastern United States (US) during the period of 2008-2010 identified a high prevalence of intersex smallmouth bass on or near US Fish & Wildlife Service National Wildlife Refuges that included the observation of 100% prevalence in smallmouth bass males collected from the Wallkill River, NJ, USA. To better assess the prevalence of intersex smallmouth bass across the state of New Jersey, a tiered reconnaissance approach was initiated during the fall of 2016. Surface water samples were collected from 101 (85 river, 16 lake/reservoir) sites across the state at base-flow conditions for estrogenicity bioassay screening. Detectable estrogenicity was observed at 90% of the sites and 64% were above the US Environmental Protection Agency trigger level of 1 ng/L. Median surface water estrogenicity was 1.8 ng/L and a maximum of 6.9 ng/L E2EqBLYES was observed. Adult smallmouth bass were collected from nine sites, pre-spawn during the spring of 2017. Intersex was identified in fish at all sites, and the composite intersex prevalence was 93.8%. Prevalence across sites ranged from 70.6% to 100%. In addition to intersex, there was detectable plasma vitellogenin in males at all sites. Total estrogenicity in surface water was determined at these fish collection sites, and notable change over time was observed. Correlation analysis indicated significant positive correlations between land use (altered land; urban + agriculture) and surface water estrogenicity. There were no clear associations between land use and organismal metrics of estrogenic endocrine disruption (intersex or vitellogenin). This work establishes a baseline prevalence of intersex in male smallmouth bass in the state of New Jersey at a limited number of locations and identifies a number of waterbodies with estrogenic activity above an effects-based threshold.

Influence of demographics, exposure, and habitat use in an urban, coastal river on tumor prevalence in a demersal fish.

Neoplasia and associated tissue biomarkers in benthic fishes are commonly used to characterize effects of contaminated sediments in aquatic ecosystems. However, these fish are often migratory or partially-migratory, and thus assessing the effect of location-specific contamination is challenging because the fish will have a complex exposure history. We determined liver and skin neoplasia prevalence for a benthic, partially-migratory fish, white sucker (Catostomus commersonii), and used carbon and nitrogen stable isotope ratios to determine the diet contribution associated with areas of contaminated sediments within the urbanized portion of the St. Louis River. We then tested which factors were significantly related to neoplasia prevalence, including age, sex, and the percent diet obtained from contaminated areas within the St. Louis River relative to Lake Superior, the reference area. Overall, the prevalence of contaminant-related internal and external tumors was low, <5%. For skin neoplasia prevalence, both sex and age were significant factors, whereas location-specific diet contribution based on stable isotope analysis was not a significant factor. For liver neoplasia prevalence, only age was a significant factor. Nevertheless, for all contaminants measured (polychlorinated biphenyls [PCBs], polychlorinated dibenzodioxins [PCDDs], and polychlorinated dibenzofurans [PCDFs]), there was a significant, negative correlation between liver tissue concentration and Lake Superior diet contribution, confirming that the St. Louis River is the primary source of contaminant exposure. The research highlights the complexity of exposure to location-specific contaminants and potentially infectious agents associated with neoplasia at urban, contaminated sites in the Great Lakes, and elsewhere. It also demonstrates the need to determine the full set of risk factors across life-stages, habitats, and biological endpoints.

Necropsy-based Wild Fish Health Assessment.

Anthropogenic influences from increased nutrients and chemical contaminants, to habitat alterations and climate change, can have significant effects on fish populations. Adverse effects monitoring, utilizing biomarkers from the organismal to the molecular level, can be used to assess the cumulative effects on fishes and other organisms. Fish health has been used worldwide as an indicator of aquatic ecosystem health. The necropsy-based fish health assessment provides data on visible abnormalities and lesions, parasites, condition and organosomatic indices. These can be compared by site, season and sex, as well as temporally, to document change over time. Severity ratings can be assigned to various observations to calculate a fish health index for more quantitative assessment. A drawback of the necropsy-based assessment is that it is based on visual observations and condition factors, which are not as sensitive as tissue and subcellular biomarkers for sublethal effects. Additionally, it is rarely possible to identify causes or risk factors associated with observed abnormalities. So, for instance a raised lesion or "tumor" on the fins, lips or body surface may be a neoplasm. However, it could also be a response to a parasite, chronic inflammation or hyperplasia of normal cells in response to an irritant. Conversely, neoplasms, certain parasites, other infectious agents and many tissue changes are not visible and so may be underestimated. However, during the necropsy-based assessment, blood (plasma), tissues for histopathology (microscopic pathology), genomics and other molecular analyses, and otoliths for aging can be collected. These downstream analyses, together with geospatial analyses, habitat assessments, water quality and contaminant analyses can all be important in comprehensive ecosystem evaluations.

Indicators of exposure to estrogenic compounds at Great Lakes Areas of Concern: species and site comparisons.

Adverse effects resulting from potential exposure of wild fishes to estrogenic endocrine disruptors were assessed at seven United States Great Lakes Areas of Concern using biomarkers ranging from organismal (gonadosomatic indices) to tissue/plasma (histology, plasma vitellogenin) and molecular (hepatic gene transcripts) levels. Biomonitoring was conducted on pelagic, top predator species, largemouth Micropterus salmoides and smallmouth M. dolomieu bass and benthic, omnivorous white sucker Catostomus commersonii. Seasonal (spring and fall) comparisons were conducted at select sites. Intersex (testicular oocytes), plasma vitellogenin, and hepatic vitellogenin transcripts were commonly observed in bass species. Testicular oocyte severity was positively, although weakly, correlated with plasma vitellogenin, hepatic transcripts of vitellogenin, estrogen receptor α, and estrogen receptor ß2, while negatively correlated with androgen receptor ß and phosphoenolpyruvate carboxykinase. No testicular oocytes were observed in white sucker; however, plasma vitellogenin and hepatic vitellogenin transcripts were commonly detected in the males. The results demonstrate the importance of utilizing multiple endpoints to assess exposure to estrogenic compounds as well as the importance of choosing sensitive species.

Micronuclei and other erythrocyte nuclear abnormalities in fishes from the Great Lakes Basin, USA.

Biological markers (biomarkers) sensitive to genotoxic and mutagenic contamination in fishes are widely used to identify exposure effects in aquatic environments. The micronucleus assay was incorporated into a suite of indicators to assess exposure to genotoxic and mutagenic contamination at five Great Lakes Areas of Concern (AOCs), as well as one non-AOC (reference) site. The assay allowed enumeration of micronuclei as well as other nuclear abnormalities for both site and species comparisons. Erythrocyte abnormality data was also compared to skin and liver tumor prevalence and hepatic transcript abundance. Erythrocyte abnormalities were observed at all sites with variable occurrence and severity among sites and species. Benthic-oriented brown bullhead (Ameiurus nebulosus) and white sucker (Catostomus commersonii) expressed lower rates of erythrocyte abnormalities, but higher rates of skin and liver neoplasms, when compared to pelagic-oriented largemouth bass (Micropterus salmoides) or smallmouth bass (Micropterus dolomieu) at the same site. The reduced erythrocyte abnormalities, increased transcript abundance associated with Phase I and II toxicant responsive pathways, and increased neoplastic lesions among benthic-oriented taxa may indicate the development of contaminant resistance of these species to more acute effects. Environ. Mol. Mutagen. 58:570-581, 2017. © 2017 This article is a U.S. Government work and is in the public domain in the USA. Environmental and Molecular Mutagenesis published by Wiley Periodicals, Inc. on behalf of Environmental Mutagen Society.