Read by QxMD icon Read


Melanie J Gallant, Natacha S Hogan
Early life-stages of amphibians rely on the innate immune system for defense against pathogens. While thyroid hormones (TH) are critical for metamorphosis and later development of the adaptive immune system, the role of TH in innate immune system development is less clear. An integral part of the innate immune response are pro-inflammatory cytokines - effector molecules that allow communication between components of the immune system. The objective of this study was to characterize the expression of key pro-inflammatory cytokines, tumor necrosis factor-α (TNFα), interleukin-1β (IL-1β) and interferon-γ (IFN-γ), throughout amphibian development and determine the impacts of thyroidal modulation on their expression...
April 12, 2018: General and Comparative Endocrinology
Chaoyou Tao, Xinshu Zou, Kai Du, Lin Zhang, Hongwei Yan, Xiaodong Yuan
Shape-tunable hollow silica nanomaterials, including hollow silica nano-spheres and nano-tadpoles, were synthesized with a one-step soft-templating method. A possible particle growth mechanism was proposed. Films were built from these shape-tunable hollow silica nanomaterials with refractive indices as low as 1.045, which is, to the best of our knowledge, the third-lowest value ever reported so far. For the first time, the refractive indices of films were tuned by changing the morphology of building blocks...
April 15, 2018: Optics Letters
Estella A Newcombe, Kiersten M Ruff, Ashish Sethi, Angelique R Ormsby, Yasmin M Ramdzan, Archa Fox, Anthony W Purcell, Paul R Gooley, Rohit V Pappu, Danny M Hatters
Soluble huntingtin exon 1 (Httex1) with expanded polyglutamine (polyQ) engenders neurotoxicity in Huntington's disease. To uncover the physical basis of this toxicity, we performed structural studies of soluble Httex1 for wild type and mutant polyQ lengths. Nuclear magnetic resonance experiments show evidence for conformational rigidity across the polyQ region. In contrast, hydrogen-deuterium exchange shows absence of backbone amide protection, suggesting negligible persistence of hydrogen bonds. The seemingly conflicting results are explained by all-atom simulations, which show that Httex1 adopts tadpole-like structures with a globular head encompassing the N-terminal amphipathic and polyQ regions and the tail encompassing the C-terminal proline-rich region...
April 5, 2018: Journal of Molecular Biology
Haihui Liu, Mingtai Chen, Lulu Liu, Saisai Ren, Panpan Cheng, Hao Zhang
Accumulating evidence indicates that mesenchymal stem cells (MSCs) have been widely used in tissue engineering and regenerative medicine due to their multilineage differentiation potentials. Recent studies show that germ-like cells can also be derived from stem cells, such as human umbilical cord MSCs and human bone marrow MSCs in vitro. However, whether human adipose-derived MSCs (hAD-MSCs) can be induced into germ-like cells has never been reported. In this study, we isolated hAD-MSCs and confirmed that their characteristics were in accordance with that of MSCs established before...
April 2018: Cellular Reprogramming
Eva-Stina Edholm, Maureen Banach, Kun Hyoe Rhoo, Martin S Pavelka, Jacques Robert
The amphibian Xenopus laevis is to date the only species outside of mammals where a MHC class I-like (MHC-like) restricted innate-like (i) T cell subset (iVα6 T cells) reminiscent of CD1d-restricted iNKT cells has been identified and functionally characterized. This provides an attractive in vivo model to study the biological analogies and differences between mammalian iT cells and the evolutionarily antecedent Xenopus iT cell defense system. Here, we report the identification of a unique iT cell subset (Vα45-Jα1...
April 2, 2018: Proceedings of the National Academy of Sciences of the United States of America
Zhenyu Liu, Katelynne B Donnelly, Kara G Pratt
The Xenopus tadpole retinotectal circuit, comprised of the retinal ganglion cells (RGCs) in the eye which form synapses directly onto neurons in the optic tectum, is a popular model to study how neural circuits self-assemble. The ability to carry out whole cell patch clamp recordings from tectal neurons and to record RGC-evoked responses, either in vivo or using a whole brain preparation, has generated a large body of high-resolution data about the mechanisms underlying normal, and abnormal, circuit formation and function...
March 15, 2018: Journal of Visualized Experiments: JoVE
Cornelius Rimayi, David Odusanya, Jana M Weiss, Jacob de Boer, Luke Chimuka, Felix Mbajiorgu
Sub-chronic toxicity of environmentally relevant atrazine concentrations on exposed tadpoles and adult male African clawed frogs (Xenopus laevis) was evaluated in a quality controlled laboratory for 90 days. The aim of this study was to determine the effects of atrazine on the survival, growth and gonad development of African clawed frogs. After exposure of tadpoles to atrazine concentrations of 0 (control), 0.01, 200 and 500 μg L-1 in water, mortality rates of 0, 0, 3.3 and 70% respectively were recorded for the 90 day exposure period...
March 23, 2018: Aquatic Toxicology
Nicola Jean Porter, Wen-Chang Li
Muscarinic acetylcholine receptors (mAChRs) mediate effects of acetylcholine (ACh) in many systems, including those involved in spinal functions like locomotion. In Xenopus laevis tadpoles at two days old, a model vertebrate for motor control research, we investigated the role of mAChRs in the skin mechanosensory pathway. We found that mAChR activation by carbachol did not affect the sensory Rohon-Beard neuron properties. However, carbachol could hyperpolarise sensory interneurons and decrease their voltage responses to outward currents...
March 27, 2018: Brain Research Bulletin
Alessandro Catenazzi, Sandra V Flechas, David Burkart, Nathan D Hooven, Joseph Townsend, Vance T Vredenburg
Emerging infectious disease is a growing threat to global health, and recent discoveries reveal that the microbiota dwelling on and within hosts can play an important role in health and disease. To understand the capacity of skin bacteria to protect amphibian hosts from the fungal disease chytridiomycosis caused by Batrachochytrium dendrobatidis (Bd), we isolated 192 bacterial morphotypes from the skin of 28 host species of frogs (families Bufonidae, Centrolenidae, Hemiphractidae, Hylidae, Leptodactylidae, Strabomantidae, and Telmatobiidae) collected from the eastern slopes of the Peruvian Andes (540-3,865 m a...
2018: Frontiers in Microbiology
Melissa Cui Bender, Caroline Hu, Chris Pelletier, Robert J Denver
Many animal life histories entail changing feeding ecology, but the molecular bases for these transitions are poorly understood. The amphibian tadpole is typically a growth and dispersal life-history stage. Tadpoles are primarily herbivorous, and they capitalize on growth opportunities to reach a minimum body size to initiate metamorphosis. During metamorphic climax, feeding declines, at which time the gastrointestinal (GI) tract remodels to accommodate the carnivorous diet of the adult frog. Here we show that anorexigenic hypothalamic feeding controls are absent in the tadpole, but develop during metamorphosis concurrent with the production of the satiety signal leptin...
March 28, 2018: Proceedings. Biological Sciences
Andrea Ferrario, Robert Merrison-Hort, Stephen R Soffe, Roman Borisyuk
Although, in most animals, brain connectivity varies between individuals, behaviour is often similar across a species. What fundamental structural properties are shared across individual networks that define this behaviour? We describe a probabilistic model of connectivity in the hatchling Xenopus tadpole spinal cord which, when combined with a spiking model, reliably produces rhythmic activity corresponding to swimming. The probabilistic model allows calculation of structural characteristics that reflect common network properties, independent of individual network realisations...
March 28, 2018: ELife
Kellie A Woll, Roderic G Eckenhoff
General anesthetics are considered among the most significant advances in modern medicine; however, they are also some of the most dangerous commonly administered drugs. Despite this, the discovery of novel anesthetics has been slow, with few clinically used agents regardless of their nearly 200-year history. Xenopus laevis frogs have a long history as a model organism and provide a vital bridge between in vitro and preclinical mammalian assays. The provided protocols are efficient and cost-effective and therefore readily amendable for high-throughput evaluation of novel anesthetic ligands...
2018: Methods in Enzymology
Eva Sidlauskaite, Jack W Gibson, Ian L Megson, Philip D Whitfield, Artak Tovmasyan, Ines Batinic-Haberle, Michael P Murphy, Peter R Moult, James N Cobley
Developmental synapse pruning refines burgeoning connectomes. The basic mechanisms of mitochondrial reactive oxygen species (ROS) production suggest they select inactive synapses for pruning: whether they do so is unknown. To begin to unravel whether mitochondrial ROS regulate pruning, we made the local consequences of neuromuscular junction (NMJ) pruning detectable as motor deficits by using disparate exogenous and endogenous models to induce synaptic inactivity en masse in developing Xenopus laevis tadpoles...
March 20, 2018: Redox Biology
Nadia C Bach, Damián J G Marino, Guillermo S Natale, Gustavo M Somoza
In the last years, the agricultural expansion has led to an increased use of pesticides, with glyphosate as the most widely used worldwide. This is also the situation in Argentina, where glyphosate formulations are the most commercialized herbicides. It is known that glyphosate formulations are much more toxic than the active ingredient, and this difference in toxicity can be attributed to the adjuvants present in the formula. In this context, the aim of the present study was to evaluate and compare sub-lethal histological effects of the glyphosate formulation Roundup Ultramax and glyphosate active ingredient on Leptodactylus latrans tadpoles at Gosner-stage 36...
March 17, 2018: Chemosphere
Caroline Peripolli Dos Santos, James Eduardo Lago Londero, Maurício Beux Dos Santos, Rayana Dos Santos Feltrin, Luiza Loebens, Livia Bataioli Moura, Sonia Zanini Cechin, André Passaglia Schuch
The increased incidence of solar ultraviolet (UV) radiation, an environmental genotoxic agent, due to ozone depletion or deforestation may help to explain the enigmatic decline of amphibian populations in specific localities. In this work, we evaluated the importance of DNA repair performed by photolyases to maintain the performance of treefrog tadpoles after acute and chronic treatments with environmental-simulated doses of solar UVB and UVA radiation. Immediately after UV treatments, tadpoles were exposed to a visible light source to activate photolyases or kept in dark containers...
March 14, 2018: Journal of Photochemistry and Photobiology. B, Biology
Adam L Crane, Douglas P Chivers, Maud C O Ferrari
Exposure to intense predation risk can induce morphological and behavioural phenotypes that prepare prey, often at young ages, for surviving attacks from unknown predators. However, previous studies revealed that this survival advantage depended on the predator species. Here, we used alarm cues from injured conspecifics to simulate a period of high predation risk for embryonic wood frogs, Lithobates sylvaticus. Two weeks post-hatching, we tested whether the embryonic risk exposure influenced survival in encounters with two novel predators: (1) a spider (Dolomedes sp...
2018: PloS One
Parthena Soupiadou, Francisco Branoner, Hans Straka
Vestibulo-ocular reflexes (VOR) are mediated by three-neuronal brainstem pathways that transform semicircular canal and otolith sensory signals into motor commands for the contraction of spatially specific sets of eye muscles. The vestibular excitation and inhibition of extraocular motoneurons underlying this reflex is reciprocally organized and allows coordinated activation of particular eye muscles and concurrent relaxation of their antagonistic counterparts. Here, we demonstrate in isolated preparations of Xenopus laevis tadpoles that the discharge modulation of superior oblique motoneurons during cyclic head motion derives from an alternating excitation and inhibition...
March 19, 2018: Journal of Neurology
Wenjun Zhang, Yuele Lu, Ledan Huang, Cheng Cheng, Shanshan Di, Li Chen, Zhiqiang Zhou, Jinling Diao
Pesticides are one of major causes for amphibian population declines and the behavior of pesticide metabolite products to amphibians has become a rising concern. In this study, the acute toxicity and the chronic effects of triadimefon and triadimenol (the metabolite of triadimefon) on Rana. nigromaculata were investigated. In the acute assay, significant differences were observed in antioxidant enzyme activities and malondialdehyde levels between the triadimefon and triadimenol. The 96 h-acute toxicity of triadimefon (25...
March 16, 2018: Ecotoxicology and Environmental Safety
Richard Mollard
This study describes the culture, cryobanking, thawing and passaging of karyotypically validated cells from two life history stages of the "least concern" Australian native amphibian species Litoria infrafrenata. Adult frog toe and tadpole macerates were generated from animals euthanized due to ill health following injury. Cultured cells proliferated and formed colonies after one to two weeks of culture. Cultures were cryopreserved in liquid nitrogen for a minimum of one month, thawed, passaged for expansion and karyotyped...
March 13, 2018: Cryobiology
Ellen A G Chernoff, Kazuna Sato, Hai V N Salfity, Deborah A Sarria, Teri Belecky-Adams
The differentiated state of spinal cord ependymal cells in regeneration-competent amphibians varies between a constitutively active state in what is essentially a developing organism, the tadpole of the frog Xenopus laevis , and a quiescent, activatable state in a slowly growing adult salamander Ambystoma mexicanum , the Axolotl. Ependymal cells are epithelial in intact spinal cord of all vertebrates. After transection, body region ependymal epithelium in both Xenopus and the Axolotl disorganizes for regenerative outgrowth (gap replacement)...
2018: Frontiers in Cellular Neuroscience
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"