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https://www.readbyqxmd.com/read/28220837/a-novel-role-of-the-organizer-gene-goosecoid-as-an-inhibitor-of-wnt-pcp-mediated-convergent-extension-in-xenopus-and-mouse
#1
Bärbel Ulmer, Melanie Tingler, Sabrina Kurz, Markus Maerker, Philipp Andre, Dina Mönch, Marina Campione, Kirsten Deißler, Mark Lewandoski, Thomas Thumberger, Axel Schweickert, Abraham Fainsod, Herbert Steinbeißer, Martin Blum
Goosecoid (Gsc) expression marks the primary embryonic organizer in vertebrates and beyond. While functions have been assigned during later embryogenesis, the role of Gsc in the organizer has remained enigmatic. Using conditional gain-of-function approaches in Xenopus and mouse to maintain Gsc expression in the organizer and along the axial midline, neural tube closure defects (NTDs) arose and dorsal extension was compromised. Both phenotypes represent convergent extension (CE) defects, arising from impaired Wnt/planar cell polarity (PCP) signaling...
February 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28220619/the-palatal-interpterygoid-vacuities-of-temnospondyls-and-the-implications-for-the-associated-eye-and-jaw-musculature
#2
Florian Witzmann, Ingmar Werneburg
A diagnostic feature of temnospondyls is the presence of an open palate with large interpterygoid vacuities, unlike the closed palate of most other early tetrapods, in which the vacuities are either slit-like or completely absent. Attachment sites on neurocranium and palatal bones in temnospondyls allow the reconstruction of a powerful m. retractor bulbi and a large, sheet-like m. levator bulbi that formed the elastic floor of the orbit. This muscle arrangement indicates that temnospondyls were able to retract the eyeballs through the interpterygoid vacuities into the buccal cavity, like extant frogs and salamanders...
February 21, 2017: Anatomical Record: Advances in Integrative Anatomy and Evolutionary Biology
https://www.readbyqxmd.com/read/28219984/motor-neurons-tune-premotor-activity-in-a-vertebrate-central-pattern-generator
#3
Kristy J Lawton, Wick M Perry, Ayako Yamaguchi, Erik Zornik
Central patterns generators (CPGs) are neural circuits that drive rhythmic motor output without sensory feedback. Vertebrate CPGs are generally believed to operate in a top-down manner in which premotor interneurons activate motor neurons that in turn drive muscles. In contrast, the frog (Xenopus laevis) vocal CPG contains a functionally unexplored neuronal projection from the motor nucleus to the premotor nucleus, indicating a recurrent pathway that may contribute to rhythm generation. In this study we characterized the function of this bottom-up connection...
February 20, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28215683/effects-of-hormonal-stimulation-on-the-concentration-and-quality-of-excreted-spermatozoa-in-the-critically-endangered-panamanian-golden-frog-atelopus-zeteki
#4
Gina Della Togna, Vance L Trudeau, Brian Gratwicke, Matthew Evans, Lauren Augustine, Han Chia, Edward J Bronikowski, James B Murphy, Pierre Comizzoli
Knowledge of basic gamete biology is critical to better protect and propagate endangered amphibian species and also to develop reproductive technologies combined with germplasm cryopreservation. The objectives of the study were to test different hormonal stimulations and then characterize the quantity and quality of Panamanian golden frog (Atelopus zeteki) spermatozoa. Following intraperitoneal injection of the gonadotropin-releasing hormone agonist (des-Gly(10), D-Ala(6), Pro-NHEt(9-)-GnRH 1, 2 or 4 μg/g of body weight), human chorionic gonadotropin (hCG; 5 or 10 IU/gbw), or Amphiplex™ (0...
March 15, 2017: Theriogenology
https://www.readbyqxmd.com/read/28213302/disrupting-effects-of-azocyclotin-to-the-hypothalamo-pituitary-gonadal-axis-and-reproduction-of-xenopus-laevis
#5
Shuying Li, Meng Li, Wenjun Gui, Qiangwei Wang, Guonian Zhu
Over the past few decades, the hazards associated with the extensive use of organictin compounds have become an issue of extreme concern, while at present the effects of these substances on amphibians remain poorly understood. In the present study, we chose azocyclotin, one of common use acaricides in China. We focused on sexual development and steroidogenesis disrupting effects of azocyclotin in the Xenopus laevis. Tadpoles were exposed to azocyclotin (0.05 and 0.5μg/L) for long-term (4 months) study. Results showed that exposure to azocyclotin caused developmental toxicity, including decreased survival, body weight, body length, gonadosomatic index, hepatosomatic index and female phenotype...
February 8, 2017: Aquatic Toxicology
https://www.readbyqxmd.com/read/28211500/video-monitoring-of-brown-planthopper-predation-in-rice-shows-flaws-of-sentinel-methods
#6
Yi Zou, Joop de Kraker, Felix J J A Bianchi, Mario D van Telgen, Haijun Xiao, Wopke van der Werf
Immobilized preys are routinely used in agro-ecological exposure studies to quantify predation of pests under field conditions, but this method has not been validated. Our purpose was to determine the validity of using immobilized adults of the major rice pest Nilaparvata lugens, brown plant hopper (BPH), as sentinels. We used direct observation by video recording to determine the causal agents of removal of field exposed BPH sentinels with two experiments: 1) we recorded removal events of dead, immobilized BPH; and 2) we compared removal of (i) dead, immobilized BPH, (ii) live, immobilized BPH, and (iii) live, mobile BPH...
February 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28208379/prediction-of-the-moments-in-advection-diffusion-lattice-boltzmann-method-i-truncation-dispersion-skewness-and-kurtosis
#7
Irina Ginzburg
The effect of the heterogeneity in the soil structure or the nonuniformity of the velocity field on the modeled resident time distribution (RTD) and breakthrough curves is quantified by their moments. While the first moment provides the effective velocity, the second moment is related to the longitudinal dispersion coefficient (k_{T}) in the developed Taylor regime; the third and fourth moments are characterized by their normalized values skewness (Sk) and kurtosis (Ku), respectively. The purpose of this investigation is to examine the role of the truncation corrections of the numerical scheme in k_{T}, Sk, and Ku because of their interference with the second moment, in the form of the numerical dispersion, and in the higher-order moments, by their definition...
January 2017: Physical Review. E
https://www.readbyqxmd.com/read/28208115/effects-of-%C3%AE-cypermethrin-enantiomers-on-the-growth-biochemical-parameters-and-bioaccumulation-in-rana-nigromaculata-tadpoles-of-the-anuran-amphibians
#8
Peng Xu, Ledan Huang
Populations of many amphibian species are declining worldwide in part because of pesticide contamination. As a surface water contaminant, α-cypermethrin may have severe ecological impacts on amphibians. Here, we examined the acute toxicity of α-cypermethrin enantiomers to dark-spotted frog Rana nigromaculata tadpoles at 24, 48, 72 and 96h, finding that the tadpoles were indeed sensitive to α-cypermethrin. The (S)-(1R, 3R)-enantiomer was approximately 29 times more toxic than the (R)-(1S, 3S)-enantiomer at 96h...
February 13, 2017: Ecotoxicology and Environmental Safety
https://www.readbyqxmd.com/read/28202572/differential-regulation-of-nmda-receptors-by-d-serine-and-glycine-in-mammalian-spinal-locomotor-networks
#9
David Acton, Gareth Brian Miles
Activation of N-methyl-D-aspartate receptors (NMDARs) requires the binding of a co-agonist, either D-serine or glycine, in addition to glutamate. Changes in occupancy of the co-agonist binding site are proposed to modulate neural networks including those controlling swimming in frog tadpoles. Here, we characterize regulation of the NMDAR co-agonist binding site in mammalian spinal locomotor networks. Blockade of NMDARs by D(-)-2-amino-5-phosphonopentanoic acid (D-APV) or 5,7-dichlorokynurenic acid reduced the frequency and amplitude of pharmacologically induced locomotor-related activity recorded from the ventral roots of spinal-cord preparations from neonatal mice...
February 15, 2017: Journal of Neurophysiology
https://www.readbyqxmd.com/read/28199338/development-and-application-of-an-edna-method-to-detect-the-critically-endangered-trinidad-golden-tree-frog-phytotriades-auratus-in-bromeliad-phytotelmata
#10
Sarah Brozio, Chloe Manson, Eleanor Gourevitch, Thomas J Burns, Mark S Greener, J Roger Downie, Paul A Hoskisson
The use of environmental DNA (eDNA) to monitor rare and elusive species has great potential for conservation biology. Traditional surveying methods can be time-consuming, labour-intensive, subject to error or can be invasive and potentially damaging to habitat. The Trinidad golden treefrog (Phytotriades auratus) is one such species that would benefit from such an approach. This species inhabits the giant bromeliad (Glomeropitcairnia erectiflora) on two peaks on the Caribbean island of Trinidad. Traditional survey methods for this species have required the destruction of the giant bromeliad, which is the only known habitat of this frog...
2017: PloS One
https://www.readbyqxmd.com/read/28198035/testing-the-effect-of-dietary-carotenoids-on-larval-survival-growth-and-development-in-the-critically-endangered-southern-corroboree-frog
#11
Phillip G Byrne, Aimee J Silla
The success of captive breeding programs (CBPs) for threatened species is often limited due to a lack of knowledge of the nutritional conditions required for optimal growth and survival. Carotenoids are powerful antioxidants known to accelerate vertebrate growth and reduce mortality. However, the effect of carotenoids on amphibian life-history traits remains poorly understood. The aim of our study was to use a manipulative laboratory experiment to test the effect of dietary-carotenoid supplementation during the larval life stage on the survival, growth and development of the critically endangered southern corroboree frog (Pseudophryne corroboree)...
February 15, 2017: Zoo Biology
https://www.readbyqxmd.com/read/28197725/schema-vs-primitive-perceptual-grouping-the-relative-weighting-of-sequential-vs-spatial-cues-during-an-auditory-grouping-task-in-frogs
#12
Hamilton E Farris, Michael J Ryan
Perceptually, grouping sounds based on their sources is critical for communication. This is especially true in túngara frog breeding aggregations, where multiple males produce overlapping calls that consist of an FM 'whine' followed by harmonic bursts called 'chucks'. Phonotactic females use at least two cues to group whines and chucks: whine-chuck spatial separation and sequence. Spatial separation is a primitive cue, whereas sequence is schema-based, as chuck production is morphologically constrained to follow whines, meaning that males cannot produce the components simultaneously...
February 15, 2017: Journal of Comparative Physiology. A, Neuroethology, Sensory, Neural, and Behavioral Physiology
https://www.readbyqxmd.com/read/28195132/analysis-of-craniocardiac-malformations-in-xenopus-using-optical-coherence-tomography
#13
Engin Deniz, Stephan Jonas, Michael Hooper, John N Griffin, Michael A Choma, Mustafa K Khokha
Birth defects affect 3% of children in the United States. Among the birth defects, congenital heart disease and craniofacial malformations are major causes of mortality and morbidity. Unfortunately, the genetic mechanisms underlying craniocardiac malformations remain largely uncharacterized. To address this, human genomic studies are identifying sequence variations in patients, resulting in numerous candidate genes. However, the molecular mechanisms of pathogenesis for most candidate genes are unknown. Therefore, there is a need for functional analyses in rapid and efficient animal models of human disease...
February 14, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28193811/the-dual-rod-system-of-amphibians-supports-colour-discrimination-at-the-absolute-visual-threshold
#14
Carola A M Yovanovich, Sanna M Koskela, Noora Nevala, Sergei L Kondrashev, Almut Kelber, Kristian Donner
The presence of two spectrally different kinds of rod photoreceptors in amphibians has been hypothesized to enable purely rod-based colour vision at very low light levels. The hypothesis has never been properly tested, so we performed three behavioural experiments at different light intensities with toads (Bufo) and frogs (Rana) to determine the thresholds for colour discrimination. The thresholds of toads were different in mate choice and prey-catching tasks, suggesting that the differential sensitivities of different spectral cone types as well as task-specific factors set limits for the use of colour in these behavioural contexts...
April 5, 2017: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
https://www.readbyqxmd.com/read/28193810/thresholds-and-noise-limitations-of-colour-vision-in-dim-light
#15
REVIEW
Almut Kelber, Carola Yovanovich, Peter Olsson
Colour discrimination is based on opponent photoreceptor interactions, and limited by receptor noise. In dim light, photon shot noise impairs colour vision, and in vertebrates, the absolute threshold of colour vision is set by dark noise in cones. Nocturnal insects (e.g. moths and nocturnal bees) and vertebrates lacking rods (geckos) have adaptations to reduce receptor noise and use chromatic vision even in very dim light. In contrast, vertebrates with duplex retinae use colour-blind rod vision when noisy cone signals become unreliable, and their transition from cone- to rod-based vision is marked by the Purkinje shift...
April 5, 2017: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
https://www.readbyqxmd.com/read/28191733/a-novel-dynamic-expression-of-vasa-in-male-germ-cells-during-spermatogenesis-in-the-chinese-soft-shell-turtle-pelidiscus-sinensis
#16
Wei Li, Piaoyi Zhang, Xuling Wu, Xinping Zhu, Hongyan Xu
vasa gene encodes a highly conserved DEAD-box RNA helicase, required for germ cell development across animal kingdom. Vasa mutations cause male infertility in mammals. It has been widely used as a biomarker for studying animal fertility or manipulating germ cells in organisms. However, in reptilians, the functions of vasa gene involved in germ cell differentiation are largely unclear; this hampers the development of biological techniques and the improvement of the productivity in these species. Here a vasa cDNA was isolated in Chinese soft-shell turtle and it predicts a protein of 691 amino acid residues, which is 72%, 69%, 58%, 59%, and 54-56% identical to its homolog from mouse, platypus, frog, chicken, and fish, respectively, and named as PsVasa...
February 13, 2017: Journal of Experimental Zoology. Part B, Molecular and Developmental Evolution
https://www.readbyqxmd.com/read/28188691/zebrafish-transgenic-constructs-label-specific-neurons-in-xenopus-laevis-spinal-cord-and-identify-frog-v0v-spinal-neurons
#17
José L Juárez-Morales, Reyna I Martinez-De Luna, Michael E Zuber, Alan Roberts, Katharine E Lewis
A correctly functioning spinal cord is crucial for locomotion and communication between body and brain but there are fundamental gaps in our knowledge of how spinal neuronal circuitry is established and functions. To understand the genetic program that regulates specification and functions of this circuitry, we need to connect neuronal molecular phenotypes with physiological analyses. Studies using Xenopus laevis tadpoles have increased our understanding of spinal cord neuronal physiology and function, particularly in locomotor circuitry...
February 11, 2017: Developmental Neurobiology
https://www.readbyqxmd.com/read/28187674/a-new-species-of-poison-dart-frog-anura-dendrobatidae-from-manu-province-amazon-region-of-southeastern-peru-with-notes-on-its-natural-history-bioacoustics-phylogenetics-and-recommended-conservation-status
#18
Shirley J Serrano-Rojas, Andrew Whitworth, Jaime Villacampa, Rudolf VON May, Roberto C Gutiérrez, José M Padial, Juan C Chaparro
We describe and name a new species of poison-dart frog from the Amazonian slopes of the Andes in Manu Province, Madre de Dios Department, Peru; specifically within the Amarakaeri Communal Reserve and the buffer zone of Manu National Park. Ameerega shihuemoy sp. nov. is supported by a unique combination of characters: black dorsum with cream to light orange dorsolateral lines, blue belly reticulated with black, and the lack of axillary, thigh and calf flash marks. Within Ameerega, it shares the general appearance of A...
January 16, 2017: Zootaxa
https://www.readbyqxmd.com/read/28187641/cryptic-within-cryptic-genetics-morphometrics-and-bioacoustics-delimitate%C3%A2-a-new-species-of-i-eleutherodactylus-i-anura-eleutherodactylidae-from-eastern-cuba
#19
Ariel Rodríguez, Álvaro Dugo-Cota, Santiago Montero-Mendieta, Alejandro Gonzalez-Voyer, Roberto Alonso Bosch, Miguel Vences, Carles Vilà
We studied the variation in genetics, bioacustics, and morphology in Eleutherodactylus glamyrus, a regionally endemic frog species restricted to high elevations in the Sierra Maestra Massif, Western Cuba that was originally described as a cryptic species hidden under the name E. auriculatus. Genetic analysis of mtDNA sequences of the 16S and cob genes identify two allopatric and strongly supported mitochondrial clades (phylogroups) which also showed no haplotype sharing in the nuclear Rag-1 gene. Bioacustic, and morphological comparisons concordantly identify these two phylogroups as independent evolutionary lineages...
January 20, 2017: Zootaxa
https://www.readbyqxmd.com/read/28186362/effects-of-the-herbicide-triclopyr-on-metamorphic-northern-red-legged-frogs
#20
Amy E Yahnke, Christian E Grue, Marc P Hayes, Schuyler Pearman-Gillman
Aquatic herbicides are used to manage invasive emergent plants in and around wetlands. Metamorphic frogs that emerge during the aquatic weed management season may be at risk of herbicide exposure. Metamorphic northern red-legged frogs (Rana aurora) were exposed to a triclopyr tank mix labelled for control of broadleaf emergent aquatic weeds such as invasive purple loosestrife (Lythrum salicaria). The tank mix consisted of Renovate® 3 (triclopyr triethylamine salt [TEA] 44.4%), the modified vegetable oil surfactant Competitor®, and marker dye Hi-Light®...
February 10, 2017: Environmental Toxicology and Chemistry
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