Cross-species apical microinjected selenomethionine toxicity in embryo-larval fishes.

Selenium (Se) is an essential micronutrient that becomes toxic when exposures minimally exceed those that are physiologically required. Studies on Se contaminated aquatic environments have identified that embryo-larval fishes are at particular risk of Se toxicity, primarily due to maternal Se transfer to developing eggs during oogenesis. This study emulated these exposures in embryo-larval fathead minnow (FHM), rainbow trout (RBT), white sucker (WSu), and white sturgeon (WSt) using embryonic selenomethionine (SeMet) microinjections.

Maternal Transfer and Apical and Physiological Effects of Dietary Hexabromocyclododecane Exposure in Parental Fathead Minnows (Pimephales promelas).

Hexabromocyclododecane (HBCD) is a persistent organic pollutant that has been characterized as an endocrine disruptor, undergoes maternal transfer, and hinders development and growth in oviparous organisms. The present study examined the apical effects of dietary HBCD (11.5, 36.

Alkylation of Benz[a]anthracene Affects Toxicity to Early-Life Stage Zebrafish and In Vitro Aryl Hydrocarbon Receptor 2 Transactivation in a Position-Dependent Manner.

Polycyclic aromatic hydrocarbons (PAHs) are structurally diverse organic chemicals that can have adverse effects on the health of fishes through activation of aryl hydrocarbon receptor 2 (AhR2). They are ubiquitous in the environment, but alkyl PAHs are more abundant in some environmental matrices. However, relatively little is known regarding the effects of alkylation on the toxicity of PAHs to fishes in vivo and how this relates to potency for activation of AhR2 in vitro.

A Novel Multispecies Toxicokinetic Modeling Approach in Support of Chemical Risk Assessment.

Standardized laboratory tests with a limited number of model species are a key component of chemical risk assessments. These surrogate species cannot represent the entire diversity of native species, but there are practical and ethical objections against testing chemicals in a large variety of species. In previous research, we have developed a multispecies toxicokinetic model to extrapolate chemical bioconcentration across species by combining single-species physiologically based toxicokinetic (PBTK) models.

Remodeling of Arctic char (Salvelinus alpinus) lipidome under a stimulated scenario of Arctic warming.

Arctic warming associated with global climate change poses a significant threat to populations of wildlife in the Arctic. Since lipids play a vital role in adaptation of organisms to variations in temperature, high-resolution mass-spectrometry-based lipidomics can provide insights into adaptive responses of organisms to a warmer environment in the Arctic and help to illustrate potential novel roles of lipids in the process of thermal adaption. In this study, we studied an ecologically and economically important species-Arctic char (Salvelinus alpinus)-with a detailed multi-tissue analysis of the lipidome in response to chronic shifts in temperature using a validated lipidomics workflow.

Development of a Comprehensive Toxicity Pathway Model for 17α-Ethinylestradiol in Early Life Stage Fathead Minnows ().

There is increasing pressure to develop alternative ecotoxicological risk assessment approaches that do not rely on expensive, time-consuming, and ethically questionable live animal testing. This study aimed to develop a comprehensive early life stage toxicity pathway model for the exposure of fish to estrogenic chemicals that is rooted in mechanistic toxicology. Embryo-larval fathead minnows (FHM; ) were exposed to graded concentrations of 17α-ethinylestradiol (water control, 0.

In ovo exposure of fathead minnow (Pimephales promelas) to selenomethionine via maternal transfer and embryo microinjection: A comparative study.

Selenium (Se) is an essential trace element of concern that is known to contaminate aquatic ecosystems as a consequence of releases from anthropogenic activities. Selenium is of particular toxicological concern for egg-laying vertebrates as they bioaccumulate Se through the diet and deposit excess Se to embryo-offspring via maternal transfer, a process which has been shown to result in significant teratogenic effects. The purpose of the present study was to determine and compare the in ovo effects of Se exposure on early development of a laboratory model fish species native to North American freshwater systems, the fathead minnow (Pimephales promelas), through two different exposure routes, maternal transfer and microinjection.

Plant cell wall glycosyltransferases: High-throughput recombinant expression screening and general requirements for these challenging enzymes.

Molecular characterization of plant cell wall glycosyltransferases is a critical step towards understanding the biosynthesis of the complex plant cell wall, and ultimately for efficient engineering of biofuel and agricultural crops. The majority of these enzymes have proven very difficult to obtain in the needed amount and purity for such molecular studies, and recombinant cell wall glycosyltransferase production efforts have largely failed. A daunting number of strategies can be employed to overcome this challenge, including optimization of DNA and protein sequences, choice of expression organism, expression conditions, co-expression partners, purification methods, and optimization of protein solubility and stability.

Historical and Contemporary Patterns of Mercury in a Hydroelectric Reservoir and Downstream Fishery: Concentration Decline in Water and Fishes.

Mercury (Hg) contamination can pose risks to human and animal health as well as commercial fisheries. Reservoir construction in riverine systems produces flooded conditions amenable to Hg(II)-methylating bacteria, which can transform this relatively benign environmental contaminant into the bioaccumulative, environmentally relevant, and neurotoxic methyl-Hg (MeHg). Hg concentrations ([Hg]) in fishes from reservoirs can take decades to decrease to pre-dam levels, but less is known about Hg exported downstream and its dynamics within downstream fish populations.

African American community leaders' policy recommendations for reducing racial disparities in HIV infection, treatment, and care: results from a community-based participatory research project in Philadelphia, Pennsylvania.

African Americans account for 45% of new HIV infections in the United States. Little empirical research investigates African American community leaders' normative recommendations for addressing these disparities. Philadelphia's HIV infection rate is 5 times the national average, nearly 70% of new infections are among African Americans, and 2% of African Americans in Philadelphia are living with HIV/AIDS.