Effects of acute exposure to the non-steroidal anti-inflammatory drug ibuprofen on the developing North American Bullfrog (Rana catesbeiana) tadpole.

A variety of pharmaceutical chemicals can represent constituents of municipal effluent outflows that are dispersed into aquatic receiving environments worldwide. Increasingly, there is concern as to the potential of such bioactive substances to interact with wildlife species at sensitive life stages and affect their biology. Using a combination of DNA microarray, quantitative real-time polymerase chain reaction, and quantitative nuclease protection assays, we assessed the ability of sub-lethal and environmentally relevant concentrations of ibuprofen (IBF), a non-steroidal anti-inflammatory agent and prevalent environmental contaminant, to function as a disruptor of endocrine-mediated post-embryonic development of the frog.

Evaluating the treatment of a synthetic wastewater containing a pharmaceutical and personal care product chemical cocktail: compound removal efficiency and effects on juvenile rainbow trout.

Pharmaceutical and personal care products (PPCPs) can evade degradation in sewage treatment plants (STPs) and can be chronically discharged into the environment, causing concern for aquatic organisms, wildlife, and humans that may be exposed to these bioactive chemicals. The ability of a common STP process, conventional activated sludge (CAS), to remove PPCPs (caffeine, di(2-ethylhexyl)phthalate, estrone, 17α-ethinylestradiol, ibuprofen, naproxen, 4-nonylphenol, tonalide, triclocarban and triclosan) from a synthetic wastewater was evaluated in the present study. The removal of individual PPCPs by the laboratory-scale CAS treatment plant ranged from 40 to 99.

Minimally invasive transcriptome profiling in salmon: detection of biological response in rainbow trout caudal fin following exposure to environmental chemical contaminants.

An increasing number of anthropogenic chemicals have demonstrated potential for disruption of biological processes critical to normal growth and development of wildlife species. Both anadromous and freshwater salmon species are at risk of exposure to environmental chemical contaminants that may affect migratory behavior, environmental fitness, and reproductive success. A sensitive metric in determination of the presence and impact of such environmental chemical contaminants is through detection of changes in the status of gene transcript levels using a targeted quantitative real-time polymerase chain reaction assay.

Triclosan exposure alters postembryonic development in a Pacific tree frog (Pseudacris regilla) Amphibian Metamorphosis Assay (TREEMA).

The Amphibian Metamorphosis Assay (AMA), developed for Xenopus laevis, is designed to identify chemicals that disrupt thyroid hormone (TH)-mediated biological processes. We adapted the AMA for use on an ecologically-relevant North American species, the Pacific tree frog (Pseudacris regilla), and applied molecular endpoints to evaluate the effects of the antibacterial agent, triclosan (TCS). Premetamorphic (Gosner stage 26-28) tadpoles were immersed for 21 days in solvent control, 1.

Effect of low dose exposure to the herbicide atrazine and its metabolite on cytochrome P450 aromatase and steroidogenic factor-1 mRNA levels in the brain of premetamorphic bullfrog tadpoles (Rana catesbeiana).

The transcriptional regulator steroidogenic factor 1 (SF-1) and the enzyme cytochrome P450 aromatase (CYP19) play a central role in modulation of a broad range of tissue-specific developmental processes associated with hormone homeostasis that includes differentiation of the central nervous system. SF-1 and CYP19 expression may be targeted by a variety of endocrine disruptive agents prevalent within the environment. In the present study, we cloned and characterized partial sequences for bullfrog (Rana catesbeiana) SF-1 and CYP19 and examined the effects of a 48h exposure to 1 and 100μg/l of the herbicide atrazine (ATZ) and its major metabolite desethylatrazine (DEA), as well as 5ng/l of the estrogenic chemical, 17α-ethynylestradiol (EE(2)), and 673ng/l of the thyroid hormone, 3,5,3'-triiodothyronine (T(3)), on SF-1 and CYP19 mRNA abundance in the brains of premetamorphic bullfrog tadpoles.

Nanometals induce stress and alter thyroid hormone action in amphibia at or below North American water quality guidelines.

Nanometals are manufactured to particle sizes with diameters in the nanometer range and are included in a variety of consumer and health products. There is a lack of information regarding potential effects of these materials on aquatic organisms. Amphibians are regarded as environmental sentinels and demonstrate an exquisite sensitivity to thyroid hormone action, a hormone that is essential for human health.

Integrating omic technologies into aquatic ecological risk assessment and environmental monitoring: hurdles, achievements, and future outlook.

Background: In this commentary we present the findings from an international consortium on fish toxicogenomics sponsored by the U.K. Natural Environment Research Council (Fish Toxicogenomics-Moving into Regulation and Monitoring, held 21-23 April 2008 at the Pacific Environmental Science Centre, Vancouver, BC, Canada).

Roscovitine inhibits thyroid hormone-induced tail regression of the frog tadpole and reveals a role for cyclin C/Cdk8 in the establishment of the metamorphic gene expression program.

The involvement of phosphorylation signaling pathways in postembryonic development of the frog is poorly understood. The thyroid hormone, 3, 5, 3'-triiodothyronine (T(3)), is essential for inducing tadpole metamorphosis and we show that the cyclin-dependent kinase (Cdk) inhibitor, roscovitine, prevents T(3)-dependent regression of cultured tail tips from Rana catesbeiana tadpoles. Using tail tips from precociously induced and naturally metamorphosing tadpoles, our data suggest that protein phosphorylation is important in the establishment of the T(3)-dependent proapoptotic gene expression program.

Identification of gene expression indicators for thyroid axis disruption in a Xenopus laevis metamorphosis screening assay. Part 1. Effects on the brain.

Thyroid hormones (TH), thyroxine (T(4)) and 3,5,3'-triiodothyronine (T(3)), play crucial roles in regulation of growth, development and metabolism in vertebrates and their actions are targets for endocrine disruptive agents. Perturbations in TH action can contribute to the development of disease states and the US Environmental Protection Agency is developing a high throughput screen using TH-dependent amphibian metamorphosis as an assay platform. Currently this methodology relies on external morphological endpoints and changes in central thyroid axis parameters.

Decreased cyclin-dependent kinase activity promotes thyroid hormone-dependent tail regression in Rana catesbeiana.

The thyroid hormone (TH), 3,5,3'-triiodothyronine (T(3)), is an important regulator of diverse cellular processes including cell proliferation, differentiation, and apoptosis, with increasing evidence that the modulation of the phosphoproteome is an important factor in the TH-mediated response. However, little is understood regarding the mechanisms whereby phosphorylation may contribute to T(3)-mediated cellular outcomes during development. The cyclin-dependent kinases (Cdks) and mitogen-activated protein kinases (MAPK/ERK) have been implicated in TH signaling in mammalian cells.

The bactericidal agent triclosan modulates thyroid hormone-associated gene expression and disrupts postembryonic anuran development.

We investigated whether exposure to environmentally relevant concentrations of the bactericidal agent, triclosan, induces changes in the thyroid hormone-mediated process of metamorphosis of the North American bullfrog, Rana catesbeiana and alters the expression profile of thyroid hormone receptor (TR) alpha and beta, basic transcription element binding protein (BTEB) and proliferating nuclear cell antigen (PCNA) gene transcripts. Premetamorphic tadpoles were immersed in environmentally relevant concentrations of triclosan and injected with 1 x 10(-11)mol/g body weight 3,5,3'-triiodothyronine (T3) or vehicle control. Morphometric measurements and steady-state mRNA levels obtained by quantitative polymerase chain reaction were determined.

Use of heterologous cDNA arrays and organ culture in the detection of thyroid hormone-dependent responses in a sentinel frog, Rana catesbeiana.

Despite the extensive use of wildlife species in elucidating important biological processes, very few gene expression tools are available. For example, many frog species with different sensitivities and ecological niches are used as sentinel species for environmental contaminants and as developmental models. However, gene expression analyses have been essentially limited to one laboratory species.