Developmental Patterns of Hepatic Peroxisome Proliferator-Activated Receptor (PPAR) Expression in Xenopus laevis and Response to Pharmaceutical Agonists During Metamorphic Climax.

Peroxisome proliferator-activated receptors (PPAR) are master transcriptional regulators that maintain metabolic homeostasis in vertebrates. Amphibians are often exposed to endocrine disrupting compounds (EDCs) that could dysregulate lipid metabolism. Larvae of the African clawed frog (Xenopus laevis) are routinely used as a model to study aquatic EDC exposures, but PPAR expression has not been characterized across larval development or metamorphosis in this species.

Sustained exposure to triclocarban and triclosan at environmental relevant concentration disrupts gut-liver axis in the black-spotted frog.

Triclocarban (TCC) and triclosan (TCS) are broad-spectrum biocides that are extensively utilized frequently contaminate water bodies and have high environmental persistence. However, the safety of TCC and TCS for wild organisms remains largely unknown. Here, we evaluated the potential health risks for black-spotted frogs (Pelophylax nigromaculatus) when exposed to TCC and TCS at concentrations of 1, 10, and 100 μg/L for 21 consecutive days.

Microcystin-LR Induces Estrogenic Effects at Environmentally Relevant Concentration in Black-Spotted Pond Frogs (): , , , and Investigations.

Harmful cyanobacterial blooms are frequent and intense worldwide, creating hazards for aquatic biodiversity. The potential estrogen-like effect of Microcystin-LR (MC-LR) is a growing concern. In this study, we assessed the estrogenic potency of MC-LR in black-spotted frogs through combined field and laboratory approaches.

Does salinity mediate the toxicity of perfluorooctanesulfonic acid (PFOS) in an estuarine fish?

Perfluorooctanesulfonic acid (PFOS) is detected in estuarine environments, where salinity levels fluctuate regularly. We investigated the effects of salinity on the toxicity of PFOS in embryos and larvae of Cyprinodon variegatus. We crossed six PFOS treatments (0, 1-10,000 μg/L) with two salinities (10, 30 ppt).

Chronic Exposure to a PFAS Mixture Resembling AFFF-Impacted Surface Water Decreases Body Size in Northern Leopard Frogs ().

Per- and polyfluoroalkyl substances (PFAS) occur in the environment as mixtures, yet mixture toxicity remains poorly understood. Aqueous film-forming foams (AFFFs) are a common source of PFAS. Our objective was to examine chronic effects of a complex PFAS mixture on amphibian growth and development.

Occurrence and implications of per and polyfluoroalkyl substances in animal feeds used in laboratory toxicity testing.

The exceptional thermal and chemical stability and the amphiphilicity of per- and polyfluoroalkyl substances (PFAS) have resulted in widespread use and subsequent contamination in environmental media and biota. Concerns surrounding toxicity have led to numerous animal-based toxicity studies. Due to the ubiquity of PFAS and the low parts per trillion (ppt) health advisory levels for drinking water, several contamination elimination protocols have been implemented.

An Environmentally Relevant Mixture of Perfluorooctanesulfonic Acid and Perfluorohexanesulfonic Acid Does Not Conform to Additivity in Northern Leopard Frogs Exposed Through Metamorphosis.

Per- and polyfluoroalkyl substances (PFAS) are chemicals associated with adverse health effects. At aqueous film-forming foam sites, they occur as mixtures, with perfluorooctanesulfonic acid (PFOS) and perfluorohexanesulfonic acid (PFHxS) commonly co-occurring in the highest concentrations. Although PFOS and PFHxS toxicities have been studied, few studies have tested their potential interaction.

Dietary exposure and accumulation of per- and polyfluoroalkyl substances alters growth and reduces body condition of post-metamorphic salamanders.

Per- and polyfluoroalkyl substances (PFAS) are contaminants of concern due to their persistence, potential to bioaccumulate, and toxicity. While dietary exposure is the primary route of exposure for terrestrial species, data on dietary PFAS uptake and adverse effects are largely restricted to mammals. As such, substantial data gaps exist that hinder ecological risk assessment, including environmentally relevant exposure levels and taxa.

Effects of larval atrazine exposure in mesocosms on Blanchard's cricket frogs (Acris blanchardi) reared through overwintering and to reproductive age.

We exposed Blanchard's cricket frog (Acris blanchardi) tadpoles to atrazine in simulated aquatic communities (outdoor mesocosms) at nominal concentrations of 0, 1, 10, 100, and 200 μg/L and tracked the effects of exposure to spring emergence in the laboratory, as well as to reproductive age in outdoor, terrestrial enclosures. We tested hypotheses that 1) atrazine addition increases the prevalence and intensity of testicular ova (TO) among phenotypic males at metamorphosis and after overwintering, 2) atrazine reduces maturation of ova after overwintering among phenotypic females, and 3) atrazine alters mass, time, and survival to metamorphosis, as well as growth and survival across terrestrial life stages. Atrazine addition increased probability of TO presence at metamorphosis, but only when treatments were pooled and compared to the control, where background atrazine was detected.

Atrazine feminizes sex ratio in Blanchard's cricket frogs (Acris blanchardi) at concentrations as low as 0.1 μg/L.

We exposed Blanchard's cricket frogs (Acris blanchardi) to ecologically relevant concentrations (0, 0.1, 1, and 10 μg/L) of a commercial formulation of atrazine throughout the larval period to determine effects on survival, somatic growth and development (time to metamorphosis and mass at metamorphosis), and gonadal development (sex ratio at metamorphosis and the prevalence of testicular ova in phenotypic males). We tested the following hypotheses: 1) atrazine feminizes the sex ratio, 2) atrazine increases the proportion of phenotypic males with testicular ova, and 3) atrazine differentially affects somatic growth (mass at metamorphosis) and development (time to metamorphosis) for males and females.

Effectiveness of a Low-Cost, Graduate Student-Led Intervention on Study Habits and Performance in Introductory Biology.

Institutions have developed diverse approaches that vary in effectiveness and cost to improve student performance in introductory science, technology, engineering, and mathematics courses. We developed a low-cost, graduate student-led, metacognition-based study skills course taught in conjunction with the introductory biology series at Miami University. Our approach aimed to improve performance for underachieving students by combining an existing framework for the process of learning (the study cycle) with concrete tools (outlines and concept maps) that have been shown to encourage deep understanding.

Short-term atrazine exposure at breeding has no impact on Blanchard's cricket frog (Acris blanchardi) reproductive success.

Studies of endocrine-disrupting contaminants have focused on early-life exposures, but later exposures could impact fitness. We exposed adult frogs (Acris blanchardi) at reproduction to ecologically relevant atrazine concentrations (0, 1, or 10 µg/L) in outdoor arenas. We measured likelihood of breeding and number of resulting tadpoles.

Variation in malathion sensitivity among populations of Blanchard's cricket frogs (Acris blanchardi) and implications for risk assessment.

Intraspecific variability in contaminant sensitivity could undermine risk assessments for nontarget organisms such as amphibians. To test how amphibian populations vary in tolerance to anticipated lethal and sublethal exposures to a pesticide, we exposed Blanchard's cricket frogs (Acris blanchardi) from 3 populations across a broad portion of their range to the insecticide malathion. Exposure in mesocosms to a nominal concentration of 1 mg/L (measured concentrations at 1 h and 24 h postaddition of 0.