Project description:An anthropogenic chemical contaminant commonly identified in aquatic receiving environments is the non-steroidal anti-inflammatory drug (NSAID), ibuprofen(IBF). While the role of ibuprofen in target organisms is known, there exists a paucity of data on the impact of exposure to non-target wildlife species. In the case of frog species, normal development and environmental fitness involves the actions of the thyroid hormones (THs), particularly at key points in the life cycle. We investigated whether exposure of premetamorphic North American bullfrog (Rana catesbeiana) tadpoles to IBF altered their response to treatment with an exogenous dose of thyroid hormone (T3).
Project description:An anthropogenic chemical contaminant commonly identified in aquatic receiving environments is the non-steroidal anti-inflammatory drug (NSAID), ibuprofen(IBF). While the role of ibuprofen in target organisms is known, there exists a paucity of data on the impact of exposure to non-target wildlife species. In the case of frog species, normal development and environmental fitness involves the actions of the thyroid hormones (THs), particularly at key points in the life cycle. We investigated whether exposure of premetamorphic North American bullfrog (Rana catesbeiana) tadpoles to IBF altered their response to treatment with an exogenous dose of thyroid hormone (T3). Six animals randomly selected from each treatment were examined for the status of the hepatic transcriptome using MAGEX DNA array analysis.
Project description:Amphibian metamorphosis involves thyroid hormone (TH)-dependent postembryonic remodeling of differentiated tissues as a tadpole transforms into a frog. Rana [Lithobates] catesbeiana (American bullfrog) metamorphosis can be precociously induced in premetamorphic tadpoles by treatment with exogenous TH. However, metamorphosis is temperature-dependent and does not occur at 5°C, even with TH treatment. Remarkably, exposure to TH at 5°C establishes a molecular memory that primes the tadpole for an accelerated metamorphosis when shifted to a permissive temperature (24°C). Previous research suggests that histone post-translational modifications (PTMs) and the incorporation of histone variants are altered upon cold temperature exposure in the presence and absence of TH. Herein, we use mass spectrometry to analyze the histone composition of premetamorphic R. catesbeiana blood, liver, and tailfin following TH injection at a permissive temperature (24°C), a non-permissive temperature (5°C), and a shifted condition (5 to 24°C). We identify changes in histone and non-histone chromatin associated protein abundance and putative PTMs, suggesting that epigenetic variations may contribute to early TH signaling events and to molecular memory.
