Xenopus laevis
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PROVIDER: PRJNA131575 | ENA |
REPOSITORIES: ENA
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Project description:Premetamorphic Xenopus laevis tadpole tail respond to thyroid hormone by resorption. The goal of this experiment is to identify the genes involved in the TH-induced resorption tadpole tail and compare it to TH-induced proliferation and differentiation program in tadpole limb and brain. Xenopus tadpoles (NF54) were treated with 100 nM T3 in 0.1 x MMR for another 24h and 48h or without T3 for 48h (control group). NF 61 tadpoles were in 0.1 X MMR till they reached NF stage 62. The tails were dissected after the experiment. Keywords: development or differentiation design,organism part comparison design,reference design,replicate design,time series design
2005-10-04 | GSE3405 | GEO
Project description:Premetamorphic Xenopus laevis tadpoles brain ventricle cells respond to thyroid hormone by proliferation and subsequent differentiation. The goal of this experiment is to identify the genes involved in the TH-induced proliferation pathway in tadpole brain and compare it to TH-induced proliferation and differentiation program in tadpole limb. Xenopus tadpoles (NF54) were treated with 1 mM methimazole in 0.1 X MMR solution for 1 week to block the endogenous TH production and reduce the TH present in the system of the tadpole. They were then treated with 100 nM T3 in 1 mM methimazole and 0.1 x MMR for another 24h and 48h or without T3 for 48h (control group). Brains from the tadpoles were dissected at the end of the experiment. Keywords: development or differentiation design,organism part comparison design,reference design,replicate design,time series design
2005-10-04 | GSE3402 | GEO
Project description:Premetamorphic Xenopus laevis tadpole tail respond to thyroid hormone by resorption. The goal of this experiment is to identify the genes involved in the TH-induced resorption tadpole tail and compare it to TH-induced proliferation and differentiation program in tadpole limb and brain. Xenopus tadpoles (NF54) were treated with 100 nM T3(triioodthyronine) in 0.1 x MMR for another 24h and 48h or without T3 for 48h (control group). NF 61 tadpoles were in 0.1 X MMR till they reached NF stage 62. The tails were dissected after the experiment.
2006-11-08 | E-MNIA-94 | biostudies-arrayexpress
Project description:Premetamorphic Xenopus laevis tadpoles limb bud cells respond to thyroid hormone by proliferation and subsequent differentiation. The goal of this experiment is to identify the genes involved in the TH-induced proliferation pathway in developing tadpole limb bud and compare it to TH-induced proliferation and differentiation program in tadpole brain. Xenopus tadpoles (NF54) were treated with 1 mM methimazole in 0.1 X MMR solution for 1 week to block the endogenous TH production and reduce the TH present in the system of the tadpole. They were then treated with 100 nM T3 in 1 mM methimazole and 0.1 x MMR for another 24h and 48h or without T3 for 48h (control group). Limb buds were dissected at the end of the experiment. Keywords: development or differentiation design,organism part comparison design,reference design,replicate design,time series design
2005-10-04 | GSE3404 | GEO
Project description:Thyroid hormone induced changes in Xenopus laevis tadpole brain
| PRJNA93535 | ENA
Project description:RNA sequencing of the proliferating Xenopus tadpole tail blastema cells
| PRJDB2519 | ENA
Project description:RIP-Chip Analysis of hnRNP K in Xenopus juvenile brain
| PRJNA134323 | ENA
Project description:Hydroxylated polychlorinated biphenyls are the metabolites produced from polychlorinated biphenyls (PCBs) by drug-metabolizing enzyme cytochrome P450 1A1. These compounds are bound to transthyretin, a major plasma thyroid hormone-binding protein in amphibian tadpoles. The compounds-transthyretin complexes are transferred into the brain across the blood brain barrier in mammals. Thus these compounds are suspected to disrupt neural development in brain. We studied about the effects of hydroxylated PCBs on the thyroid system in brain using metamorphosing tadpoles of African clawed toad, Xenopus laevis. The metamorphosis assay revealed that these compounds had inhibitory effects on the thyroid hormone-induced metamorphosis. This in vivo assay was a powerful tool to detect thyroid-disrupting activities, because we were not able to detect the inhibitory effects of these compounds using thyroid hormone-responsive reporter gene assay in a cultured Xenopus cell line. A genome-wide gene expression analysis in brain following short-term exposure to these compounds demonstrated that the delay of metamorphosis and the morphological thyroid-disrupting changes could be caused partially by disruption of the thyroid hormone-induced gene expression by hydroxylated PCBs. Furthermore, we associated functional ontology terms with the transcripts whose expression were altered by thyroid hormone alone, or thyroid hormone and hydroxylated PCBs. We suggested that these approachs using a technique of bioinformatics revealed molecular mechanism of thyroid-disrupting activities in vivo. Thyroid hormones induce amphibian metamorphosis and alter a lot of thyroid hormone-responsive gene expression. We studied about the effects of hydroxylated PCBs on TH-induced gene expression. Premetamorphic tadpoles were treated with 500 nM hydroxylated PCBs in the presence of 1 nM thyroid hormone for 4 days. After exposure period total RNA was extracted from brain. Study included at least three replicate of each treatment.
2010-12-31 | E-GEOD-23154 | biostudies-arrayexpress
Project description:Pregnane X receptor (PXR) is generally considered the most important sensor of natural and anthropogenic xenobiotics in vertebrates. In Xenopus, however, PXR plays a role in neural development and it is irresponsive to xenobiotics. We report a first broad-spectrum amphibian xenobiotic receptor, which is an ortholog of the mammalian constitutive androstane receptor (CAR). The low basal activity and pronounced responsiveness to activators such as drugs and steroids displayed by the Xenopus CAR resemble PXR, which both trace back to a common ancestor early in the divergence of land vertebrates. The constitutive activity of CAR emerged first in Sauropsida (reptiles and birds) and it is common to all fully terrestrial land vertebrates (Amniota). This activity can be mimicked by humanizing just two amino acids of the Xenopus CAR. These results demonstrate a remarkable plasticity of CAR which enabled its employment as Xenopus xenosensors. They open way to toxicogenomic and bioaugmentation studies in amphibians, a critically endangered taxon of land vertebrates. Taken together, we provide evidence for a much earlier origin of CAR, for its conservation in tetrapods which exceeds that of PXR, and for its remarkable functional plasticity which enabled its role as a PXR-like xenosensor in Amphibia.
2011-10-11 | GSE28510 | GEO
Project description:Hydroxylated polychlorinated biphenyls are the metabolites produced from polychlorinated biphenyls (PCBs) by drug-metabolizing enzyme cytochrome P450 1A1. These compounds are bound to transthyretin, a major plasma thyroid hormone-binding protein in amphibian tadpoles. The compounds-transthyretin complexes are transferred into the brain across the blood brain barrier in mammals. Thus these compounds are suspected to disrupt neural development in brain. We studied about the effects of hydroxylated PCBs on the thyroid system in brain using metamorphosing tadpoles of African clawed toad, Xenopus laevis. The metamorphosis assay revealed that these compounds had inhibitory effects on the thyroid hormone-induced metamorphosis. This in vivo assay was a powerful tool to detect thyroid-disrupting activities, because we were not able to detect the inhibitory effects of these compounds using thyroid hormone-responsive reporter gene assay in a cultured Xenopus cell line. A genome-wide gene expression analysis in brain following short-term exposure to these compounds demonstrated that the delay of metamorphosis and the morphological thyroid-disrupting changes could be caused partially by disruption of the thyroid hormone-induced gene expression by hydroxylated PCBs. Furthermore, we associated functional ontology terms with the transcripts whose expression were altered by thyroid hormone alone, or thyroid hormone and hydroxylated PCBs. We suggested that these approachs using a technique of bioinformatics revealed molecular mechanism of thyroid-disrupting activities in vivo.
2010-12-31 | GSE23154 | GEO