The movement of large amounts of nutrients by migrating animals has ecological benefits for recipient food webs that may be offset by co-transported contaminants. Salmon spawning migrations are archetypal of this process, carrying marine-derived materials to inland ecosystems where they stimulate local productivity but also enhance contaminant exposure. Pacific salmon abundance and biomass are higher now than in the last century, reflecting substantial shifts in community structure that probably altered nutrient versus contaminant delivery.
View Article and Find Full Text PDFIn the Lake Koocanusa-Kootenai River system (Montana, USA and British Columbia, Canada), selenium (Se) contamination has become an international concern and is suspected to contribute to the observed burbot (Lota lota) population collapse. Due to our limited ability to sample burbot in Lake Koocanusa for monitoring studies, we used a reference population to develop tools to model tissue Se disposition for a focal species in systems with elevated Se. Total Se concentrations in otoliths, biofluids (blood and endolymph), and tissues (muscle, liver, and ovary) from burbot in reference lakes in northwestern Ontario, Canada, were measured to document tissue-to-tissue Se relationships and evaluate the potential for otoliths to retrace Se exposure in fish.
View Article and Find Full Text PDFHydrologic and irrigation regimes mediate the timing of selenium (Se) mobilization to rivers, but the extent to which patterns in Se uptake and trophic transfer through recipient food webs reflect the temporal variation in Se delivery is unknown. We investigated Se mobilization, partitioning, and trophic transfer along approximately 60 river miles of the selenium-impaired segment of the Lower Gunnison River (Colorado, USA) during six sampling trips between June 2015 and October 2016. We found temporal patterns in Se partitioning and trophic transfer to be independent of those in dissolved Se concentrations and that the recipient food web sustained elevated Se concentrations from earlier periods of high Se mobilization.
View Article and Find Full Text PDFMercury (Hg) is a pervasive environmental pollutant and contaminant of concern for both people and wildlife that has been a focus of environmental remediation efforts for decades. A growing body of literature has motivated calls for revising Hg consumption advisories to co-consider selenium (Se) levels in seafood and implies that remediating aquatic ecosystems with ecosystem-scale Se additions could be a robust solution to Hg contamination. Provided that elevated Se concentrations are also known toxicological threats to aquatic animals, we performed a literature search to evaluate the strength of evidence supporting three assertions underpinning the ameliorating benefits of Se: (1) dietary Se reduces MeHg toxicity in consumers; (2) environmental Se reduces Hg bioaccumulation and biomagnification in aquatic food webs; and (3) Se inhibits Hg bioavailability to, and/or methylmercury production by, microbial communities.
View Article and Find Full Text PDFCoal combustion residuals (CCRs, also known as "coal ash") contain high concentrations of toxic and carcinogenic elements that can pose ecological and human health risks upon their release into the environment. About half of the CCRs that are generated annually in the U.S.
View Article and Find Full Text PDFEffluents from coal-fired power plant ash ponds are a major source of environmental contamination, annually loading more than a million metric tons of pollutants to aquatic ecosystems in the United States alone. Though this waste stream is characterized by elevated concentrations of numerous inorganic constituents, decades of previous research effort have focused on the ecotoxicological consequences of a single stressor: selenium. In this study, we compared concentrations of 10 trace elements among three North Carolina reservoirs with varying burdens following decades of coal combustion residual (CCR) inputs.
View Article and Find Full Text PDFAnthropogenic activities resulting in releases of selenium-laden waste streams threaten freshwater ecosystems. Lake ecosystems demand special consideration because they are characterized by prolonged retention of selenium and continuous cycling of the element through the food chain, through which it becomes available to toxicologically susceptible egg-laying vertebrates. This study documents the current selenium burden of lakes in North Carolina (NC) with historic selenium inputs from nearby coal-fired power plants.
View Article and Find Full Text PDFAutoimmune diseases (ADs) are estimated to affect between 5 and 8 % of the US population, and approximately 80 % of these patients are women. Sjögren's syndrome (SS) is an AD that occurs predominately in women over men (16:1). The hallmark characteristic of SS is diminished secretory production from the primary exocrine gland and the lacrimal or salivary glands resulting in symptoms of dry eye and mouth.
View Article and Find Full Text PDFMyocarditis is more severe in men than in women and difficult to diagnose due to a lack of imaging modalities that directly detect myocardial inflammation. Translocator protein 18 kDa (TSPO) is used extensively to image brain inflammation due to its presence in CD11b(+) brain microglia. In this study, we examined expression of TSPO and CD11b in mice with coxsackievirus B3 (CVB3) myocarditis and biopsy sections from myocarditis patients in order to determine if it could be used to image myocarditis.
View Article and Find Full Text PDFAm J Physiol Regul Integr Comp Physiol
February 2013
Recent findings indicate that TLR3 polymorphisms increase susceptibility to enteroviral myocarditis and inflammatory dilated cardiomyopathy (iDCM) in patients. TLR3 signaling has been found to inhibit coxsackievirus B3 (CVB3) replication and acute myocarditis in mouse models, but its role in the progression from myocarditis to iDCM has not been previously investigated. In this study we found that TLR3 deficiency increased acute (P = 5.
View Article and Find Full Text PDFBackground: IL-33 through its receptor ST2 protects the heart from myocardial infarct and hypertrophy in animal models but, paradoxically, increases autoimmune disease. In this study, we examined the effect of IL-33 or ST2 administration on autoimmune heart disease.
Methods And Results: We used pressure-volume relationships and isoproterenol challenge to assess the effect of recombinant (r) IL-33 or rST2 (eg, soluble ST2) administration on the development of autoimmune coxsackievirus B3 myocarditis and dilated cardiomyopathy in male BALB/c mice.
Am J Physiol Heart Circ Physiol
April 2012
Myocarditis and dilated cardiomyopathy (DCM) are often caused by viral infections and occur more frequently in men than in women, but the reasons for the sex difference remain unclear. The aim of this study was to assess whether gene changes in the heart during coxsackievirus B3 (CVB3) myocarditis in male and female BALB/c mice predicted worse DCM in males. Although myocarditis (P = 4.
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