A Comparative Table of Anuran Normal Tables

Nieuwkoop, P.D.; Faber, J.S. Faber

doi:10.1201/9781003064565-29

Cited by 6 publications

(9 citation statements)

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“…For example, tail resorption is the last step in metamorphosis because it must occur after limb development is complete and the limbs are functional for locomotion. Under natural development, it takes approximately two months to go from a fertilized egg through a larval tadpole to a juvenile frog, with the metamorphic transition from tadpole to frog taking approximately 4.5 weeks under ideal conditions (13,18,21,59).…”

Section: Discussionmentioning

confidence: 99%

“…Statistics were performed using 2-way 9 ANOVA analysis with a Sidak's multiple comparison test (MCT) in GraphPad Prism 9. Sequences for the primers used for quantitative PCR are given S1 Table . Transgenic tadpole luciferase reporter assay: NF 54 tadpoles, sorted at 1wk-PF for GFP+ expression in the eye lens, were staged by assessing morphology of the hind limb, according to the normal scale by Nieuwkoop and Faber (59), and then treated through their rearing water for two days as previously described (50). Treatment concentrations were 10 nM T3 and 2 nM TBT.…”

Section: Gene Expressionmentioning

confidence: 99%

“…While 1wk-PF tadpoles are considered only partially competent to respond to THs, tadpoles at NF 54 (approximately 26 days PF) are considered fully competent to respond to THs and to be entering metamorphosis (21,49,61). We raised tadpoles to NF 54, using hind limb development to determine the developmental stage (59), and then treated them with 10 nM T3 in the presence and absence of 30 nM Bex to investigate whether the RXR agonist could still potentiate the action of T3 in a fully competent tadpole. Tadpoles were treated for three days with compounds (a longer treatment time was not possible due to the extreme gill resorption in T3 plus Bex animals), and then we measured the LJ angle.…”

Section: Rxr Agonists Potentiate T3-action In Th-competent (Nf 54) Tadpolesmentioning

confidence: 99%

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Retinoid-X Receptor Agonists Increase Thyroid Hormone Competence in Lower Jaw Remodeling of Pre-Metamorphic Xenopus laevis tadpoles

Mengeling

Vetter

Furlow

2021

Preprint

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Thyroid hormone (TH) signaling plays critical roles during vertebrate development, including regulation of skeletal and cartilage growth. TH acts through its receptors (TRs), nuclear hormone receptors (NRs) that heterodimerize with Retinoid-X receptors (RXRs), to regulate gene expression. A defining difference between NR signaling during development compared to in adult tissues, is competence, the ability of the organism to respond to an endocrine signal. Amphibian metamorphosis, especially in Xenopus laevis, the African clawed frog, is a well-established in vivo model for studying the mechanisms of TH action during development. Previously, we’ve used one-week post-fertilization X. laevis tadpoles, which are only partially competent to TH, to show that in the tail, which is naturally refractive to exogenous T3 at this stage, RXR agonists increase TH competence, and that RXR antagonism inhibits the TH response. Here, we focused on the jaw that undergoes dramatic TH-mediated remodeling during metamorphosis in order to support new feeding and breathing styles. We used a battery of approaches in one-week-old tadpoles, including quantitative morphology, differential gene expression and whole mount cell proliferation assays, to show that both pharmacologic (bexarotene) and environmental (tributyltin) RXR agonists potentiated TH-induced responses but were inactive in the absence of TH; and the RXR antagonist UVI 3003 inhibited TH action. At this young age, the lower jaw has not developed to the point that T3-induced changes produce an adult-like jaw morphology, and we found that increasing TH competence with RXR agonists did not give us a more natural-metamorphic phenotype, even though Bex and TBT significantly potentiated cellular proliferation and the TH induction of runx2, a transcription factor critical for developing cartilage and bone. Prominent targets of RXR-mediated TH potentiation were members of the matrix metalloprotease family, suggesting that RXR potentiation may emphasize pathways responsible for rapid changes during development.

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Section: Discussionmentioning

confidence: 99%

Section: Gene Expressionmentioning

confidence: 99%

Section: Rxr Agonists Potentiate T3-action In Th-competent (Nf 54) Tadpolesmentioning

confidence: 99%

See 1 more Smart Citation

Retinoid-X Receptor Agonists Increase Thyroid Hormone Competence in Lower Jaw Remodeling of Pre-Metamorphic Xenopus laevis tadpoles

Mengeling

Vetter

Furlow

2021

Preprint

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“…The EVL, on the other hand, is an outer epithelium that is proposed to have evolved as a permeability barrier (see above, §7c) derived from the surface epithelial layer of an ancestral actinopterygian, that is observed in present-day amphibians [15,17]. In support of this idea, the EVL of zebrafish and the surface epithelial layer of Xenopus, which have been studied in some detail, both derive from the outermost layer of the blastoderm and form distinct outer epithelial sheets joined by tight junctions that serve a primarily protective function [70,299]. However, the EVL surrounds the entire embryo at all stages and, with few exceptions (see above, §5d), forms the periderm which functions as a primitive skin [24,60,69,70].…”

Section: Evolutionary Origin Of Teleost Extraembryonic Structuresmentioning

confidence: 99%

Origin, form and function of extraembryonic structures in teleost fishes

Concha

Reig

2022

Phil. Trans. R. Soc. B

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Teleost eggs have evolved a highly derived early developmental pattern within vertebrates as a result of the meroblastic cleavage pattern, giving rise to a polar stratified architecture containing a large acellular yolk and a small cellular blastoderm on top. Besides the acellular yolk, the teleost-specific yolk syncytial layer (YSL) and the superficial epithelial enveloping layer are recognized as extraembryonic structures that play critical roles throughout embryonic development. They provide enriched microenvironments in which molecular feedback loops, cellular interactions and mechanical signals emerge to sculpt, among other things, embryonic patterning along the dorsoventral and left–right axes, mesendodermal specification and the execution of morphogenetic movements in the early embryo and during organogenesis. An emerging concept points to a critical role of extraembryonic structures in reinforcing early genetic and morphogenetic programmes in reciprocal coordination with the embryonic blastoderm, providing the necessary boundary conditions for development to proceed. In addition, the role of the enveloping cell layer in providing mechanical, osmotic and immunological protection during early stages of development, and the autonomous nutritional support provided by the yolk and YSL, have probably been key aspects that have enabled the massive radiation of teleosts to colonize every ecological niche on the Earth. This article is part of the theme issue ‘Extraembryonic tissues: exploring concepts, definitions and functions across the animal kingdom’.

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“…A complete metamorphosis developmental study was conducted in which four replicates of 20 young gastrula stage embryos (NF stage 10) (Nieuwkoop & Faber, 1994) per treatment were exposed to dechlorinated tap water (control) or varying concentrations of PFOS through 150 dpm. A mini-diluter flow-through exposure system (Benoit, Mattson, & Olson, 1981) was used to deliver five test concentrations (0.06, 0.13, 0.25, 0.50 and 1.0 mg PFOS/L [nominal]) and a control (dechlorinated tap water) with complete volume exchange every 6.5 hours.…”

Section: Perfluorooctanesulfonate Exposurementioning

confidence: 99%

Effect of perfluorooctanesulfonate exposure on steroid hormone levels and steroidogenic enzyme activities in juvenile Silurana tropicalis

Fort

Mathis

Fort

et al. 2019

J of Applied Toxicology

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The impact of the perfluoro‐chemical, perfluorooctanesulfonate (PFOS), on gonadal steroidogenesis during sexual differentiation in Silurana tropicalis was examined because of its ubiquity in the environment, bioaccumulative nature and potential to disturb endocrine activity. A partial life cycle study exposing S. tropicalis to varying concentrations of PFOS 0.06, 0.13, 0.25, 0.50 and 1.0 mg PFOS/L [nominal]) was conducted. Gonad and plasma samples were collected from juvenile control specimens and organisms exposed to PFOS from early embryo through 150 days post‐metamorphosis. Gonad CYP17, aromatase and 5α‐reductase activities were measured. Plasma estradiol, testosterone, dihydrotestosterone (DHT) and gonadal testosterone were measured in both males and females. Increased plasma DHT and gonadal testosterone were found in PFOS‐treated juvenile male S. tropicalis compared to controls. Decreased plasma estradiol, but not testosterone, was detected in PFOS‐treated female S. tropicalis compared to controls. Plasma DHT was not detected and an increase in gonadal testosterone was detected in PFOS‐treated female frogs. Female S. tropicalis exposed to PFOS exhibited a concentration‐related decrease in the mean aromatase activity, but not 5α‐reductase. PFOS exposure in male frogs induced a concentration‐related increase in 5α‐reductase activity, but did not alter aromatase activity compared to control frogs. A concentration‐related increase in CYP 17,20‐lyase activity, but not 17‐hydroxylase activity, was found in both female and male S. tropicalis exposed to PFOS.

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A Comparative Table of Anuran Normal Tables

Cited by 6 publications

References 0 publications

Retinoid-X Receptor Agonists Increase Thyroid Hormone Competence in Lower Jaw Remodeling of Pre-Metamorphic Xenopus laevis tadpoles

Retinoid-X Receptor Agonists Increase Thyroid Hormone Competence in Lower Jaw Remodeling of Pre-Metamorphic Xenopus laevis tadpoles

Origin, form and function of extraembryonic structures in teleost fishes

Effect of perfluorooctanesulfonate exposure on steroid hormone levels and steroidogenic enzyme activities in juvenile Silurana tropicalis

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