| assays to study mitotic centrosome and spindle pole assembly and regulation. | faithful chromosome segregation during cell division requires proper bipolar spindle assembly and critically depends on spindle pole integrity. in most animal cells, spindle poles form as the result of the concerted action of various factors operating in two independent pathways of microtubule assembly mediated by chromatin/rangtp and by centrosomes. mutation or deregulation of a number of spindle pole-organizing proteins has been linked to human diseases, including cancer and microcephaly. our ... | 2016 | 27193852 |
| encapsulation of xenopus egg and embryo extract spindle assembly reactions in synthetic cell-like compartments with tunable size. | methods are described for preparing xenopus laevis egg and embryo cytoplasm and encapsulating extract spindle assembly reactions in cell-like compartments to investigate the effects of cell size on intracellular assembly. cytoplasm prepared from the eggs or embryos of individual frogs is screened for the ability to form interphase nuclei and metaphase spindles, and subsequently packaged, along with dna, into droplets of varying size using microfluidics. the dimensions of these cell-like droplets ... | 2016 | 27193845 |
| visualizing and analyzing branching microtubule nucleation using meiotic xenopus egg extracts and tirf microscopy. | mitotic and meiotic spindles consist primarily of microtubules, which originate from centrosomes and within the vicinity of chromatin. indirect evidence suggested that microtubules also originate throughout the spindle, but the high microtubule density within the spindle precludes the direct observation of this phenomenon. by using meiotic xenopus laevis egg extract and employing total internal reflection (tirf) microscopy, microtubule nucleation from preexisting microtubules could be demonstrat ... | 2016 | 27193844 |
| mechanical roles of apical constriction, cell elongation, and cell migration during neural tube formation in xenopus. | neural tube closure is an important and necessary process during the development of the central nervous system. the formation of the neural tube structure from a flat sheet of neural epithelium requires several cell morphogenetic events and tissue dynamics to account for the mechanics of tissue deformation. cell elongation changes cuboidal cells into columnar cells, and apical constriction then causes them to adopt apically narrow, wedge-like shapes. in addition, the neural plate in xenopus is s ... | 2016 | 27193152 |
| from meiosis to mitosis - the sperm centrosome defines the kinetics of spindle assembly after fertilization in xenopus. | bipolar spindle assembly in the vertebrate oocyte relies on a self-organization chromosome-dependent pathway. upon fertilization, the male gamete provides a centrosome, and the first and subsequent embryonic divisions occur in the presence of duplicated centrosomes that act as dominant microtubule organizing centres (mtocs). the transition from meiosis to embryonic mitosis involves a necessary adaptation to integrate the dominant chromosome-dependent pathway with the centrosomes to form the bipo ... | 2016 | 27179073 |
| lateral line scene analysis in the purely aquatic frog xenopus laevis daudin (pipidae). | the ability to locate and discriminate water surface waves that impinge simultaneously from multiple directions was studied in the clawed frog, xenopus laevis. monofrequency waves of 5-30 hz were presented from point sources at a distance of 10 cm from the frog, unless stated otherwise, and the animal's response turn towards the wave origin examined. two-choice conditioning with two simultaneous frontal waves at a 90-degree inter-wave angle revealed discrimination thresholds lower than 1 hz for ... | 2016 | 27172931 |
| with no lysine l-wnk1 isoforms are negative regulators of the k+-cl- cotransporters. | the k(+)-cl(-) cotransporters (kcc1-kcc4) encompass a branch of the slc12 family of electroneutral cation-coupled chloride cotransporters that translocate ions out of the cell to regulate various factors, including cell volume and intracellular chloride concentration, among others. l-wnk1 is an ubiquitously expressed kinase that is activated in response to osmotic stress and intracellular chloride depletion, and it is implicated in two distinct hereditary syndromes: the renal disease pseudohypoa ... | 2016 | 27170636 |
| neural activity-dependent regulation of radial glial filopodial motility is mediated by glial cgmp-dependent protein kinase 1 and contributes to synapse maturation in the developing visual system. | radial glia in the developing optic tectum extend highly dynamic filopodial protrusions within the tectal neuropil, the motility of which has previously been shown to be sensitive to neural activity and nitric oxide (no) release. using in vivo two-photon microscopy, we performed time-lapse imaging of radial glial cells and measured filopodial motility in the intact albino xenopus laevis tadpole. application of mk801 to block neuronal nmda receptor (nmdar) currents confirmed a significant reducti ... | 2016 | 27170125 |
| technique to target microinjection to the developing xenopus kidney. | the embryonic kidney of xenopus laevis (frog), the pronephros, consists of a single nephron, and can be used as a model for kidney disease. xenopus embryos are large, develop externally, and can be easily manipulated by microinjection or surgical procedures. in addition, fate maps have been established for early xenopus embryos. targeted microinjection into the individual blastomere that will eventually give rise to an organ or tissue of interest can be used to selectively overexpress or knock d ... | 2016 | 27168375 |
| trialkyltin rexinoid-x receptor agonists selectively potentiate thyroid hormone induced programs of xenopus laevis metamorphosis. | the trialkyltins tributyltin (tbt) and triphenyltin (tpt) can function as rexinoid-x receptor (rxr) agonists. we recently showed that rxr agonists can alter thyroid hormone (th) signaling in a mammalian pituitary th-responsive reporter cell line, gh3.tre-luc. the prevalence of tbt and tpt in the environment prompted us to test whether they could also affect th signaling. both trialkyltins induced the integrated luciferase reporter alone and potentiated th activation at low doses. trimethyltin, w ... | 2016 | 27167774 |
| assessing primary neurogenesis in xenopus embryos using immunostaining. | primary neurogenesis is a dynamic and complex process during embryonic development that sets up the initial layout of the central nervous system. during this process, a portion of neural stem cells undergo differentiation and give rise to the first populations of differentiated primary neurons within the nascent central nervous system. several vertebrate model organisms have been used to explore the mechanisms of neural cell fate specification, patterning, and differentiation. among these is the ... | 2016 | 27166855 |
| deep-brain photoreception links luminance detection to motor output in xenopus frog tadpoles. | nonvisual photoreceptors are widely distributed in the retina and brain, but their roles in animal behavior remain poorly understood. here we document a previously unidentified form of deep-brain photoreception in xenopus laevis frog tadpoles. the isolated nervous system retains sensitivity to light even when devoid of input from classical eye and pineal photoreceptors. these preparations produce regular bouts of rhythmic swimming activity in ambient light but fall silent in the dark. this sensi ... | 2016 | 27166423 |
| delineating the grin1 phenotypic spectrum: a distinct genetic nmda receptor encephalopathy. | to determine the phenotypic spectrum caused by mutations in grin1 encoding the nmda receptor subunit glun1 and to investigate their underlying functional pathophysiology. | 2016 | 27164704 |
| novel exon 1 protein-coding regions n-terminally extend human kcne3 and kcne4. | the 5 human (h)kcne β subunits each regulate various cation channels and are linked to inherited cardiac arrhythmias. reported here are previously undiscovered protein-coding regions in exon 1 of hkcne3 and hkcne4 that extend their encoded extracellular domains by 44 and 51 residues, which yields full-length proteins of 147 and 221 residues, respectively. full-length hkcne3 and hkcne4 transcript and protein are expressed in multiple human tissues; for hkcne4, only the longer protein isoform is d ... | 2016 | 27162025 |
| xenmine: a genomic interaction tool for the xenopus community. | the xenopus community has embraced recent advances in sequencing technology, resulting in the accumulation of numerous rna-seq and chip-seq datasets. however, easily accessing and comparing datasets generated by multiple laboratories is challenging. thus, we have created a central space to view, search and analyze data, providing essential information on gene expression changes and regulatory elements present in the genome. xenmine (www.xenmine.org) is a user-friendly website containing publishe ... | 2017 | 27157655 |
| prolonged vestibular stimulation induces homeostatic plasticity of the vestibulo-ocular reflex in larval xenopus laevis. | vestibulo-ocular reflexes (vor) stabilise retinal images during head/body motion in vertebrates by generating spatio-temporally precise extraocular motor commands for corrective eye movements. while vor performance is generally robust with a relatively stable gain, cerebellar circuits are capable of adapting the underlying sensory-motor transformation. here, we studied cerebellum-dependent vor plasticity by recording head motion-induced lateral rectus and superior oblique extraocular motor disch ... | 2016 | 27152983 |
| high-resolution scanning electron microscopy and immuno-gold labeling of the nuclear lamina and nuclear pore complex. | scanning electron microscopy (sem) is a technique used to image surfaces. field emission sems (fesems) can resolve structures that are ~0.5-1.5 nm apart. fesem, therefore is a useful technique for imaging molecular structures that exist at surfaces such as membranes. the nuclear envelope consists of four membrane surfaces, all of which may be accessible for imaging. imaging of the cytoplasmic face of the outer membrane gives information about ribosomes and cytoskeletal attachments, as well as de ... | 2016 | 27147058 |
| color and intensity discrimination in xenopus laevis tadpoles. | investigations into the physiology of xenopus laevis have the potential to greatly accelerate biomedical research, especially concerning neural plasticity and sensory systems, but are limited by the lack of available information on behavioral learning in this species. here, we attempt to lay the foundations for a behavioral assay in xenopus that can be used in conjunction with biological manipulations. we tested cohorts of xenopus tadpoles across four light-mediated active-avoidance experiments, ... | 2016 | 27146661 |
| development of the larval amphibian growth and development assay: effects of chronic 4-tert-octylphenol or 17β-trenbolone exposure in xenopus laevis from embryo to juvenile. | the larval amphibian growth and development assay (lagda) is a globally harmonized test guideline developed by the u.s. environmental protection agency in collaboration with japan's ministry of the environment. the lagda was designed to evaluate apical effects of chronic chemical exposure on growth, thyroid-mediated amphibian metamorphosis and reproductive development. during the validation phase, two well-characterized endocrine-disrupting chemicals were tested to evaluate the performance of th ... | 2016 | 27143402 |
| pharmacological characterization of histamine-gated chloride channels from the housefly musca domestica. | the biogenic amine histamine (ha) is not only the neurotransmitter of photoreceptors but also has important roles in mechanosensory reception, temperature preference, sleep and olfactory processing in insects. two cdnas (mdhcla and mdhclb) that encode ha-gated chloride channel subunits (mdhcla and mdhclb) were cloned from the housefly musca domestica. the crnas were injected into xenopus laevis oocytes to examine the functions and pharmacological characteristics of mdhcla and mdhclb channels usi ... | 2017 | 27139242 |
| a novel synaptic plasticity rule explains homeostasis of neuromuscular transmission. | excitability differs among muscle fibers and undergoes continuous changes during development and growth, yet the neuromuscular synapse maintains a remarkable fidelity of execution. here we show in two evolutionarily distant vertebrates (xenopus laevis cell culture and mouse nerve-muscle ex-vivo) that the skeletal muscle cell constantly senses, through two identified calcium signals, synaptic events and their efficacy in eliciting spikes. these sensors trigger retrograde signal(s) that control pr ... | 2016 | 27138195 |
| high-resolution full-field optical coherence microscopy using a broadband light-emitting diode. | high-resolution full-field optical coherence microscopy (ff-ocm) is demonstrated using a single broadband light-emitting diode (led). the characteristics of the led-illumination ff-ocm system are measured and compared to those obtained using a halogen lamp, the light source of reference in ff-ocm. both light sources yield identical performance in terms of spatial resolution and detection sensitivity, using the same setup and camera. in particular, an axial resolution of 0.7 μm (in water) is reac ... | 2016 | 27137603 |
| optimization and comparison of bottom-up proteomic sample preparation for early-stage xenopus laevis embryos. | xenopus laevis is an important model organism in developmental biology. while there is a large literature on changes in the organism's transcriptome during development, the study of its proteome is at an embryonic state. several papers have been published recently that characterize the proteome of x. laevis eggs and early-stage embryos; however, proteomic sample preparation optimizations have not been reported. sample preparation is challenging because a large fraction (~90 % by weight) of the e ... | 2016 | 27137514 |
| spatiotemporal dynamics of the nuclear pore complex transport barrier resolved by high-speed atomic force microscopy. | nuclear pore complexes (npcs) are biological nanomachines that mediate the bidirectional traffic of macromolecules between the cytoplasm and nucleus in eukaryotic cells. this process involves numerous intrinsically disordered, barrier-forming proteins known as phenylalanine-glycine nucleoporins (fg nups) that are tethered inside each pore. the selective barrier mechanism has so far remained unresolved because the fg nups have eluded direct structural analysis within npcs. here, high-speed atomic ... | 2016 | 27136131 |
| [the point mutation in noggin2 protein that enhances its ability to bind activin]. | earlier we have revealed the ability of noggin family proteins to bind a member of the tuf-β superfamily, activinb, and to repress the activin-dependent smad2 signaling cascade. in the present work we have characterized a mutant of the xenopus laevis noggin2, bearing the substitution w203r. we have shown that this point mutation enhances the affinity of noggin2 to activinb, while weakens its affinity to bmp. consistently, we have shown that w203 r mutant inhibits smad2 signaling cascade more eff ... | 2016 | 27125031 |
| [the cytoskelrtal protein zvxin interacts with the hedgehog receptor patched]. | earlier, we demonstrated zyxin influence upon hedgehog (hh)-signaling pathway during early patterning of the central neural system (cns) anlage of the xenopus laevis embryo. now we show that zyxin can physically interact with the transmembrane receptor of hh, patched2 (ptc2). binding of hh by this receptor activates signaling pathway, which regulates many events, including numerous types of cell differentiation during the embryonic development. in particular, patterning of the cns anlage. the ab ... | 2016 | 27125030 |
| surface area of carbon nanoparticles: a dose metric for a more realistic ecotoxicological assessment. | engineered nanoparticles such as graphenes, nanodiamonds, and carbon nanotubes correspond to different allotropes of carbon and are among the best candidates for applications in fast-growing nanotechnology. it is thus likely that they may get into the environment at each step of their life cycle: production, use, and disposal. the aquatic compartment concentrates pollutants and is expected to be especially impacted. the toxicity of a compound is conventionally evaluated using mass concentration ... | 2016 | 27124492 |
| osr1 and spak sensitivity of large-conductance ca2+ activated k+ channel. | the oxidative stress-responsive kinase 1 (osr1) and the serine/threonine kinases spak (sps1-related proline/alanine-rich kinase) are under the control of wnk (with-no-k [lys]) kinases. osr1 and spak participate in diverse functions including cell volume regulation and neuronal excitability. cell volume and neuronal excitation are further modified by the large conductance ca2+-activated k+ channels (maxi k+ channel or bk channels). an influence of osr1 and/or spak on bk channel activity has, howe ... | 2016 | 27119824 |
| heterogeneous inhibition in macroscopic current responses of four nicotinic acetylcholine receptor subtypes by cholesterol enrichment. | the nicotinic acetylcholine receptor (nachr), located in the cell membranes of neurons and muscle cells, mediates the transmission of nerve impulses across cholinergic synapses. in addition, the nachr is also found in the electric organs of electric rays (e.g., the genus torpedo). cholesterol, which is a key lipid for maintaining the correct functionality of membrane proteins, has been found to alter the nachr function. we were thus interested to probe the changes in the functionality of differe ... | 2016 | 27116687 |
| centromeric dna replication reconstitution reveals dna loops and atr checkpoint suppression. | half of the human genome is made up of repetitive dna. however, mechanisms underlying replication of chromosome regions containing repetitive dna are poorly understood. we reconstituted replication of defined human chromosome segments using bacterial artificial chromosomes in xenopus laevis egg extract. using this approach we characterized the chromatin assembly and replication dynamics of centromeric alpha-satellite dna. proteomic analysis of centromeric chromatin revealed replication-dependent ... | 2016 | 27111843 |
| expanding the genetic toolkit in xenopus: approaches and opportunities for human disease modeling. | the amphibian model xenopus, has been used extensively over the past century to study multiple aspects of cell and developmental biology. xenopus offers advantages of a non-mammalian system, including high fecundity, external development, and simple housing requirements, with additional advantages of large embryos, highly conserved developmental processes, and close evolutionary relationship to higher vertebrates. there are two main species of xenopus used in biomedical research, xenopus laevis ... | 2017 | 27109192 |
| adaptive plasticity of spino-extraocular motor coupling during locomotion in metamorphosing xenopus laevis. | during swimming in the amphibian italic! xenopus laevis, efference copies of rhythmic locomotor commands produced by the spinal central pattern generator (cpg) can drive extraocular motor output appropriate for producing image-stabilizing eye movements to offset the disruptive effects of self-motion. during metamorphosis, italic! x. laevisremodels its locomotor strategy from larval tail-based undulatory movements to bilaterally synchronous hindlimb kicking in the adult. this change in propulsive ... | 2016 | 27103674 |
| selective inhibition of the kinase dyrk1a by targeting its folding process. | autophosphorylation of amino-acid residues is part of the folding process of various protein kinases. conventional chemical screening of mature kinases has missed inhibitors that selectively interfere with the folding process. here we report a cell-based assay that evaluates inhibition of a kinase at a transitional state during the folding process and identify a folding intermediate-selective inhibitor of dual-specificity tyrosine-phosphorylation-regulated kinase 1a (dyrk1a), which we refer to a ... | 2016 | 27102360 |
| xenopus: leaping forward in kidney organogenesis. | while kidney donations stagnate, the number of people in need of kidney transplants continues to grow. although transplanting culture-grown organs is years away, pursuing the engineering of the kidney de novo is a valid means of closing the gap between the supply and demand of kidneys for transplantation. the structural organization of a mouse kidney is similar to that of humans. therefore, mice have traditionally served as the primary model system for the study of kidney development. the mouse ... | 2017 | 27099217 |
| early ketamine exposure results in cardiac enlargement and heart dysfunction in xenopus embryos. | ketamine is a commonly used clinical anesthetic and a popular recreational drug. however, with the exception of studies about the nervous system, studies about the effect of early ketamine exposure on embryos are rare. xenopus laevis is a commonly used vertebrate model for assessing teratogenicity. therefore, we treated xenopus embryos with ketamine to evaluate its teratogenicity on embryos. | 2016 | 27091482 |
| potentiating effect of glabridin from glycyrrhiza glabra on gabaa receptors. | extracts from glycyrrhiza are traditionally used for the treatment of insomnia and anxiety. glabridin is one of the main flavonoid compounds from glycyrrhiza glabra and displays a broad range of biological properties. in the present work, we investigated the effect of glabridin on gabaa receptors. for this purpose, we employed the two-electrode voltage-clamp technique on xenopus laevis oocytes expressing recombinant gabaa receptors. through this approach, we observed that glabridin presents a st ... | 2016 | 29214227 |
| perfluoroalkylated substance effects in xenopus laevis a6 kidney epithelial cells determined by atr-ftir spectroscopy and chemometric analysis. | the effects of four perfluoroalkylated substances (pfass), namely, perfluorobutanesulfonate (pfbs), perfluorooctanoic acid (pfoa), perfluorooctanesulfonate (pfos), and perfluorononanoic acid (pfna) were assessed in xenopus laevis a6 kidney epithelial cells by attenuated total reflection fourier-transform infrared (atr-ftir) spectroscopy and chemometric analysis. principal component analysis-linear discriminant analysis (pca-lda) was used to visualize wavenumber-related alterations and anova-simu ... | 2016 | 27078751 |
| inhibition of intestinal α-glucosidase and glucose absorption by feruloylated arabinoxylan mono- and oligosaccharides from corn bran and wheat aleurone. | the effect of feruloylated arabinoxylan mono- and oligosaccharides (faxmo) on mammalian α-glucosidase and glucose transporters was investigated using human caco-2 cells, rat intestinal acetone powder, and xenopus laevis oocytes. the isolated faxmo from wheat aleurone and corn bran were identified to have degree of polymerization (dp) of 4 and 1, respectively, by hplc-ms. both faxmo extracts were effective inhibitors of sucrase and maltase functions of the α-glucosidase. the ic50 for faxmo extrac ... | 2016 | 27073693 |
| thyroid hormone activates wnt/β-catenin signaling involved in adult epithelial development during intestinal remodeling in xenopus laevis. | during amphibian intestinal remodeling, thyroid hormone (th) induces some larval epithelial cells to dedifferentiate into adult stem cells, which newly generate the absorptive epithelium analogous to the mammalian epithelium. to clarify molecular mechanisms underlying adult epithelial development, we here focus on th response genes that are associated with the canonical wnt pathway. our quantitative reverse transcription plus polymerase chain reaction and immunohistochemical analyses indicate th ... | 2016 | 27068920 |
| evaluating the teratogenicity of the selective ß3-adrenoceptor agonist, cl 316.243 hydrate by employing fetax (frog embryo teratogenesis assay). | in this study, the frog embryo teratogenesis assay (fetax - xenopus) technique was employed to evaluate the potential teratogenicity of the selective ß-adrenoceptor (ar) agonist, cl 316.243. in this context, cl 316.243 was applied to the south african clawed frog (xenopus laevis) embryos. the media containing the cl 316.24-exposed embryos were monitored and changed/replaced once every 24 hours. using fetax, we determined the minimum concentrations to inhibit growth (mcig) for cl 316.243. the 96- ... | 2017 | 27063898 |
| evaluation of microtransplantation of rat brain neurolemma into xenopus laevis oocytes as a technique to study the effect of neurotoxicants on endogenous voltage-sensitive ion channels. | microtransplantation of mammalian brain neurolemma into the plasma membrane of xenopus oocytes is used to study ion channels in their native form as they appear in the central nervous system. use of microtransplanted neurolemma is advantageous for various reasons: tissue can be obtained from various sources and at different developmental stages; ion channels and receptors are present in their native configuration in their proper lipid environment along with appropriate auxiliary subunits; allowi ... | 2017 | 27063102 |
| neurotransmitter signaling pathways required for normal development in xenopus laevis embryos: a pharmacological survey screen. | neurotransmitters are not only involved in brain function but are also important signaling molecules for many diverse cell types. neurotransmitters are widely conserved, from evolutionarily ancient organisms lacking nervous systems through man. here, results are reported from a loss- and gain-of-function survey, using pharmacological modulators of several neurotransmitter pathways to examine possible roles for these pathways in normal embryogenesis. applying reagents targeting the glutamatergic, ... | 2016 | 27060969 |
| expression and purification of the full murine npm2 and study of its interaction with protamines and histones. | mouse nucleoplasmin m.npm2 was recombinantly expressed and the protein consisting of the complete sequence was purified and characterized. similar to its xenopus laevis x.npm2 counterpart, the protein forms stable pentameric complexes and exhibits an almost undistinguishable hydrodynamic ionic strength-dependent unfolding behavior. the interaction of n.pm2 with histones and mouse p1/p2 protamines revealed that these chromosomal proteins bind preferentially to the distal part of the nucleoplasmin ... | 2016 | 28955874 |
| effects of cd2+ on the epithelial na+ channel (enac) investigated by experimental and modeling studies. | the function of the epithelial na+ channel from the apical membrane of many na+ transporting epithelia is modulated by various chemical compounds from the extracellular space, such as heavy metals, protons or chloride ions. we have studied the effect of extracellular cd2+ on the function of the epithelial na+ channel (enac) in heterologously expressed xenopus laevis oocytes and na+-transporting epithelia. we assayed channel function as the amiloride-sensitive sodium current (i(na)). cd2+ rapidly ... | 2016 | 27045669 |
| erratum: reappraising the effects of artemisinin on the atpase activity of pfatp6 and serca1a e255l expressed in xenopus laevis oocytes. | | 2016 | 27045446 |
| xenopus genomic data and browser resources. | the two species of xenopus most commonly used in biomedical research are the diploid xenopus (silurana) tropicalis and the tetraploid xenopus laevis. the x. tropicalis genome sequence has been available since 2010 and this year the x. laevis, genome from two distinct genetic backgrounds has been published. multiple genome assemblies available for both species and transcriptomic and epigenetic data sets are growing rapidly, all of which are available from a variety of web resources. this review d ... | 2017 | 27039265 |
| identification and characterization of heptapeptide modulators of the glycine receptor. | the glycine receptor is a member of the cys-loop receptor superfamily of ligand-gated ion channels and is implicated as a possible therapeutic target for the treatment of diseases such as alcoholism and inflammatory pain. in humans, four glycine receptor subtypes (α1, α2, α3, and β) co-assemble to form pentameric channel proteins as either α homomers or αβ heteromers. to date, few agents have been identified that can selectively modulate the glycine receptor, especially those possessing subtype ... | 2016 | 27038522 |
| identification and functional characterization of four transient receptor potential ankyrin 1 variants in apolygus lucorum (meyer-dür). | as signal integrators that respond to various physical and chemical stimuli, transient receptor potential (trp) channels fulfil critical functional roles in the sensory systems of both vertebrate and invertebrate organisms. here, four variants of trp ankyrin 1 (trpa1) were identified and cloned from the green plant bug, apolygus lucorum. spatiotemporal expression profiling across development and in different adult tissues revealed that the highest relative-transcript levels occurred in first-ins ... | 2016 | 27038267 |
| [identification of a novel calcium (ca^(2+))-activated chloride channel accessory gene in xenopus laevis]. | calcium (ca^(2+))-activated chloride channel accessories (clcas) are putative anion channel-related proteins with diverse physiological functions. exploring clca diversity is important for prediction of gene structure and function. in an effort to identify novel clca genes in xenopus laevis, we successfully cloned and characterized a xenopus laevis cdna predicted to encode the xclca3 gene. cloning of xclca3 was achieved by computational analysis, rapid amplification of cdna ends (race), and a ti ... | 2016 | 27028816 |
| evolution of heat sensors drove shifts in thermosensation between xenopus species adapted to different thermal niches. | temperature is one of the most critical environmental factors affecting survival, and thus species that inhabit different thermal niches have evolved thermal sensitivities suitable for their respective habitats. during the process of shifting thermal niches, various types of genes expressed in diverse tissues, including those of the peripheral to central nervous systems, are potentially involved in the evolutionary changes in thermosensation. to elucidate the molecular mechanisms behind the evol ... | 2016 | 27022021 |
| effects of gsm-like radiofrequency irradiation during the oogenesis and spermiogenesis of xenopus laevis. | we aimed to evaluate the effect of gsm-like radiofrequency electromagnetic radiation (rf-emr) on the oogenesis, and spermiogenesis of xenopus laevis, and so the development of the embryos obtained from normal females+normal males (i.e. "n(f)+n(m)"); normal females+rf-exposed males (i.e. "n(f)+rf(m)"); rf-exposed female+normal male (i.e. "rf(f)+n(m)"); and rf-exposed female+rf-exposed male (i.e. "rf(f)+rf(m)". various, assessments were performed to determine potential teratogenic effects and mort ... | 2016 | 27017260 |
| genome-wide analysis of dorsal and ventral transcriptomes of the xenopus laevis gastrula. | rna sequencing has allowed high-throughput screening of differential gene expression in many tissues and organisms. xenopus laevis is a classical embryological and cell-free extract model system, but its genomic sequence had been lacking due to difficulties arising from allotetraploidy. there is currently much excitement surrounding the release of the completed x. laevis genome (version 9.1) by the joint genome institute (jgi), which provides a platform for genome-wide studies. here we present a ... | 2017 | 27016259 |
| mapping neurogenesis onset in the optic tectum of xenopus laevis. | neural progenitor cells have a central role in the development and evolution of the vertebrate brain. during early brain development, neural progenitors first expand their numbers through repeated proliferative divisions and then begin to exhibit neurogenic divisions. the transparent and experimentally accessible optic tectum of xenopus laevis is an excellent model system for the study of the cell biology of neurogenesis, but the precise spatial and temporal relationship between proliferative an ... | 2016 | 27012549 |
| neural regeneration dynamics of xenopus laevis olfactory epithelium after zinc sulfate-induced damage. | neural stem cells (nscs) of the olfactory epithelium (oe) are responsible for tissue maintenance and the neural regeneration after severe damage of the tissue. in the normal oe, nscs are located in the basal layer, olfactory receptor neurons (orns) mainly in the middle layer, and sustentacular (sus) cells in the most apical olfactory layer. in this work, we induced severe damage of the oe through treatment with a zinc sulfate (znso4) solution directly in the medium, which resulted in the loss of ... | 2016 | 27012180 |
| single-cell mass spectrometry with multi-solvent extraction identifies metabolic differences between left and right blastomeres in the 8-cell frog (xenopus) embryo. | single-cell metabolic mass spectrometry enables the discovery (untargeted) analysis of small molecules in individual cells. using single-cell capillary electrophoresis high-resolution mass spectrometry (ce-hrms), we recently uncovered small-molecule differences between embryonic cells located along the animal-vegetal and dorsal-ventral axes of the 16-cell frog (xenopus laevis) embryo, raising the question whether metabolic cell heterogeneity also exists along the left-right body axis. to address ... | 2016 | 27004603 |
| an early developmental vertebrate model for nanomaterial safety: bridging cell-based and mammalian toxicity assessment. | with the rise in production of nanoparticles (nps) for an ever-increasing number of applications, there is an urgent need to efficiently assess their potential toxicity. we propose a np hazard assessment protocol that combines mammalian cytotoxicity data with embryonic vertebrate abnormality scoring to determine an overall toxicity index. | 2016 | 27003295 |
| expressional characterization of mrna (guanine-7) methyltransferase (rnmt) during early development of xenopus laevis. | methylation of the guanosine cap structure at the 5' end of mrna is essential for efficient translation of all eukaryotic cellular mrnas, gene expression and cell viability and promotes transcription, splicing, polyadenylation and nuclear export of mrna. in the current study, we present the spatial expression pattern of the xenopus laevis rnmt homologue. a high percentage of protein sequence similarity, especially within the methyltransferase domain, as well as an increased expression in the cel ... | 2016 | 27002806 |
| generation of a xenopus laevis f1 albino j strain by genome editing and oocyte host-transfer. | completion of the xenopus laevis genome sequence from inbred j strain animals has facilitated the generation of germline mutant x. laevis using targeted genome editing. in the last few years, numerous reports have demonstrated that talens are able to induce mutations in f0 xenopus embryos, but none has demonstrated germline transmission of such mutations in x. laevis. in this report we used the oocyte host-transfer method to generate mutations in both tyrosinase homeologs and found highly-penetr ... | 2017 | 26993591 |
| gabaa receptor modulation by phenyl ring compounds is associated with a water solubility cut-off value. | the modulation of n-methyl-d-aspartate receptors is associated with a molar water solubility cut-off effect of approximately 1.1 mmol/l and hence are unaffected by significantly less soluble compounds. however, compounds with this molar water solubility are still able to modulate x03b3;-aminobutyric acid type a (gabaa) receptors. we hypothesized that gabaa receptor modulation by phenolic compounds would exhibit cut-off at a molar water solubility value less than 1.1 mmol/l. | 2016 | 26986632 |
| noggin4 is a long-range inhibitor of wnt8 signalling that regulates head development in xenopus laevis. | noggin4 is a noggin family secreted protein whose molecular and physiological functions remain unknown. in this study, we demonstrate that in contrast to other noggins, xenopus laevis noggin4 cannot antagonise bmp signalling; instead, it specifically binds to wnt8 and inhibits the wnt/β -catenin pathway. live imaging demonstrated that noggin4 diffusivity in embryonic tissues significantly exceeded that of other noggins. using the fluorescence recovery after photobleaching (frap) assay and mathem ... | 2016 | 26973133 |
| exposure to butachlor causes thyroid endocrine disruption and promotion of metamorphosis in xenopus laevis. | butachlor is extensively applied in rice paddy ecosystem in china, and has been widespread contaminant in the aquatic environment. here, xenopus laevis was used for the evaluation of teratogenesis developmental toxicity, and disruption of thyroid system when exposure to different concentrations of butachlor by window phase exposure. acute toxicity investigation shown that 96 h-lc50 value of butachlor was 1.424 mg l(-1) and 0.962 mg l(-1) for tadpoles (starting from stages 46/47) and embryos (sta ... | 2016 | 26971167 |
| thyroid endocrine disruption of azocyclotin to xenopus laevis during metamorphosis. | organotin compounds are ubiquitous contaminants that are frequently detected in the environment and in biota, which raises concern about their risk to wildlife and human health. in the present study, nieuwkoop & faber stage 51 xenopus laevis tadpoles were exposed to different concentrations of azocyclotin (0, 0.02, 0.1 and 0.5μg/l) for 21 days, during which time the tadpoles underwent morphological development. exposure to azocyclotin caused an inhibitory effect on the pre-metamorphic developmen ... | 2016 | 26970056 |
| rescue of protein expression defects may not be enough to abolish the pro-arrhythmic phenotype of long qt type 2 mutations. | most missense long qt syndrome type 2 (lqts2) mutations result in kv11.1 channels that show reduced levels of membrane expression. pharmacological chaperones that rescue mutant channel expression could have therapeutic potential to reduce the risk of lqts2-associated arrhythmias and sudden cardiac death, but only if the mutant kv11.1 channels function normally (i.e. like wt channels) after membrane expression is restored. fewer than half of mutant channels exhibit relatively normal function afte ... | 2016 | 26958806 |
| a novel short anionic antibacterial peptide isolated from the skin of xenopus laevis with broad antibacterial activity and inhibitory activity against breast cancer cell. | a vastarray of bioactive peptides from amphibian skin secretions is attracting increasing attention due to the growing problem of bacteria resistant to conventional antibiotics. in this report, a small molecular antibacterial peptide, named xenopus laevis antibacterial peptide-p1 (xlasp-p1), was isolated from the skin of xenopus laevis using reversed-phase high-performance liquid chromatography. the primary structure of xlasp-p1, which has been proved to be a novel peptide by blast search in amp ... | 2016 | 26952034 |
| a specialized mechanism of translation mediated by fxr1a-associated micrornp in cellular quiescence. | micrornas predominantly decrease gene expression; however, specific mrnas are translationally upregulated in quiescent (g0) mammalian cells and immature xenopus laevis oocytes by an fxr1a-associated microrna-protein complex (micrornp) that lacks the micrornp repressor, gw182. their mechanism in these conditions of decreased mtor signaling, and therefore reduced canonical (cap-and-poly(a)-tail-mediated) translation, remains undiscovered. our data reveal that mtor inhibition in human thp1 cells en ... | 2016 | 26942679 |
| pdzrn3 is required for pronephros morphogenesis in xenopus laevis. | pdzrn3, a multidomain protein with e3-ubiquitin ligase activity, has been reported to play a role in myoblast and osteoblast differentiation and, more recently, in neuronal and endothelial cell development. the expression of the pdzrn3 gene is developmentally regulated in various vertebrate tissues, including muscular, neural and vascular system. little is known about its expression during kidney development, although genetic polymorphisms and alterations around the human pdzrn3 chromosomal regi ... | 2016 | 26934292 |
| association of plasminuria with overhydration in patients with ckd. | hypervolemia is a common feature of patients with ckd and associated with hypertension. recent work has shown stimulation of sodium retention by urinary plasmin during nephrotic syndrome. however, it is unclear whether plasminuria plays a role in patients with stable ckd and non-nephrotic proteinuria. | 2016 | 26933188 |
| towards the bridging of molecular genetics data across xenopus species. | the clawed african frog xenopus laevis has been one of the main vertebrate models for studies in developmental biology. however, for genetic studies, xenopus tropicalis has been the experimental model of choice because it shorter life cycle and due to a more tractable genome that does not result from genome duplication as in the case of x. laevis. today, although still organized in a large number of scaffolds, nearly 85% of x. tropicalis and 89% of x. laevis genomes have been sequenced. there is ... | 2016 | 26925848 |
| xcyp26c induced by inhibition of bmp signaling is involved in anterior-posterior neural patterning of xenopus laevis. | vertebrate neurogenesis requires inhibition of endogenous bone morphogenetic protein (bmp) signals in the ectoderm. blocking of bmps in animal cap explants causes the formation of anterior neural tissues as a default fate. to identify genes involved in the anterior neural specification, we analyzed gene expression profiles using a xenopus affymetrix gene chip after bmp-4 inhibition in animal cap explants. we found that the xcyp26c gene, encoding a retinoic acid (ra) degradation enzyme, was upreg ... | 2016 | 26923193 |
| fast-onset lidocaine block of rat nav1.4 channels suggests involvement of a second high-affinity open state. | local anesthetics (las) block resting, open, and inactivated states of voltage-gated na(+) channels where inactivated states are thought to bind with highest affinity. however, reports of fast-onset block occurring over milliseconds hint at high-affinity block of open channels. movement of voltage-sensor domain iv-segment 4 (divs4) has been associated with high affinity la block termed voltage-sensor block (vsb) that also leads to a second open state. these observations point to a second high-af ... | 2016 | 26922882 |
| iron overload leading to torsades de pointes in β-thalassemia and long qt syndrome. | the authors present a unique case of torsades de pointes in a β-thalassemia patient with early iron overload in the absence of any structural abnormalities as seen in hemochromatosis. genetic testing showed a novel kcnq1 gene mutation 1591c>t [gln531ter(x)]. testing of the gene mutation in xenopus laevis oocytes showed loss of function of the iks current. the authors hypothesize that iron overload combined with the kcnq1 gene mutation leads to prolongation of qtc and torsades de pointes. | 2016 | 26920202 |
| hedgehog inhibition causes complete loss of limb outgrowth and transformation of digit identity in xenopus tropicalis. | the study of the tetrapod limb has contributed greatly to our understanding of developmental pathways and how changes to these pathways affect the evolution of morphology. most of our understanding of tetrapod limb development comes from research on amniotes, with far less known about mechanisms of limb development in amphibians. to better understand the mechanisms of limb development in anuran amphibians, we used cyclopamine to inhibit hedgehog signaling at various stages of development in the ... | 2016 | 26918681 |
| polyunsaturated fatty acids are potent openers of human m-channels expressed in xenopus laevis oocytes. | polyunsaturated fatty acids have been reported to reduce neuronal excitability, in part by promoting inactivation of voltage-gated sodium and calcium channels. effects on neuronal potassium channels are less explored and experimental data ambiguous. the aim of this study was to investigate anti-excitable effects of polyunsaturated fatty acids on the neuronal m-channel, important for setting the resting membrane potential in hippocampal and dorsal root ganglion neurones. | 2016 | 26914447 |
| in vivo tracking of histone h3 lysine 9 acetylation in xenopus laevis during tail regeneration. | xenopus laevis tadpoles can completely regenerate their appendages, such as tail and limbs, and therefore provide a unique model to decipher the molecular mechanisms of organ regeneration in vertebrates. epigenetic modifications are likely to be involved in this remarkable regeneration capacity, but they remain largely unknown. to examine the involvement of histone modification during organ regeneration, we generated transgenic x. laevis ubiquitously expressing a fluorescent modification-specifi ... | 2016 | 26914410 |
| reduction in e-cadherin expression fosters migration of xenopus laevis primordial germ cells. | the transition from passive to active migration of primordial germ cells in xenopus embryos correlates with a reduction in overall adhesion to surrounding endodermal cells as well as with reduced e-cadherin expression. single cell force spectroscopy, in which cells are brought into brief contact with a gold surface functionalized with e-cadherin constructs, allows for a quantitative estimate of functional e-cadherin molecules on the cell surface. the adhesion force between migratory pgcs and the ... | 2016 | 26907205 |
| post-transcriptional regulation mediated by specific neurofilament introns in vivo. | neurons regulate genes post-transcriptionally to coordinate the supply of cytoskeletal proteins, such as the medium neurofilament (nefm), with demand for structural materials in response to extracellular cues encountered by developing axons. by using a method for evaluating functionality of cis-regulatory gene elements in vivo through plasmid injection into xenopus embryos, we discovered that splicing of a specific nefm intron was required for robust transgene expression, regardless of promoter ... | 2016 | 26906423 |
| c21orf59/kurly controls both cilia motility and polarization. | cilia are microtubule-based projections that function in the movement of extracellular fluid. this requires cilia to be: (1) motile and driven by dynein complexes and (2) correctly polarized on the surface of cells, which requires planar cell polarity (pcp). few factors that regulate both processes have been discovered. we reveal that c21orf59/kurly (kur), a cytoplasmic protein with some enrichment at the base of cilia, is needed for motility; zebrafish mutants exhibit characteristic development ... | 2016 | 26904945 |
| tumor protein tctp regulates axon development in the embryonic visual system. | the transcript encoding translationally controlled tumor protein (tctp), a molecule associated with aggressive breast cancers, was identified among the most abundant in genome-wide screens of axons, suggesting that tctp is important in neurons. here, we tested the role of tctp in retinal axon development in xenopus laevis we report that tctp deficiency results in stunted and splayed retinotectal projections that fail to innervate the optic tectum at the normal developmental time owing to impaire ... | 2016 | 26903505 |
| insights into the gate of the nuclear pore complex. | nuclear pore complexes (npcs) serve as the gateway of the cell nucleus. these macromolecular assemblies form selective aqueous translocation channels permitting the free diffusion of small molecules, as well as receptor-mediated transport of large cargoes. over the past decade, major progress has been made in both the structural determination of individual nucleoporins and subcomplexes by x-ray crystallography and in the structural analysis of the entire npc by cryo-electron tomography (cryo-et) ... | 2016 | 26902931 |
| follicle cell trypsin-like protease hrovochymase: its cdna cloning, localization, and involvement in the late stage of oogenesis in the ascidian halocynthia roretzi. | we previously reported that the sperm trypsin-like protease hracrosin and its precursor hrproacrosin participate in fertilization of the ascidian halocynthia roretzi. the hrproacrosin gene is annotated in the h. roretzi genome database as harore.cg.mtp2014.s89.g15383; our previously reported sequence of hrproacrosin gene appeared to include four nucleotides inserted near the 3'-end of hrproacrosin, resulting in a frame-shift mutation and a premature termination codon. the gene architecture of hr ... | 2016 | 26896838 |
| cftr channel in oocytes from xenopus laevis and its regulation by xshroom1 protein. | shroom is a family of related proteins linked to the actin cytoskeleton. xshroom1 is constitutively expressed in xenopus laevis oocytes, and it is required for the expression of the epithelial sodium channel (enac). as there is a close relationship between enac and the cystic fibrosis transmembrane regulator (cftr), we examined the action of xshroom1 on cftr expression and activity. biotinylation was used to measure cftr surface expression, and currents were registered with voltage clamp when st ... | 2016 | 26888038 |
| a mechanism to enhance cellular responsivity to hormone action: krüppel-like factor 9 promotes thyroid hormone receptor-β autoinduction during postembryonic brain development. | thyroid hormone (th) receptor (tr)-β (trb) is induced by th (autoinduced) in xenopus tadpoles during metamorphosis. we previously showed that krüppel-like factor 9 (klf9) is rapidly induced by th in the tadpole brain, associates in chromatin with the trb upstream region in a developmental stage and th-dependent manner, and forced expression of klf9 in the xenopus laevis cell line xtc-2 accelerates and enhances trb autoinduction. here we investigated whether klf9 can promote trb autoinduction in ... | 2016 | 26886257 |
| the d-amino acid transport by the invertebrate slc6 transporters kaat1 and caatch1 from manduca sexta. | the ability of the slc6 family members, the insect neutral amino acid cotransporter kaat1(k(+)-coupled amino acid transporter 1) and its homologous caatch1(cation anion activated amino acid transporter/channel), to transport d-amino acids has been investigated through heterologous expression in xenopus laevis oocytes and electrophysiological techniques. in the presence of d-isomers of leucine, serine, and proline, the mskaat1 generates inward, transport-associated, currents with variable relativ ... | 2016 | 26884475 |
| collagenoma in an african clawed frog (xenopus laevis). | a 3-y-old female xenopus laevis was reported for a gray mass on the abdomen. the frog was used for egg collection and was otherwise experimentally naïve. on physical exam, the frog was bright and active and had a firm, gray, lobulated mass (1.5 cm × 0.5 cm × 0.5 cm) in the cutaneous tissue of the left lateral abdomen. an excisional biopsy was performed under anesthesia, and the entire mass was removed and processed for histopathology. microscopically, the dermis was greatly expanded by connectiv ... | 2016 | 26884406 |
| retigabine holds kv7 channels open and stabilizes the resting potential. | the anticonvulsant retigabine is a kv7 channel agonist used to treat hyperexcitability disorders in humans. retigabine shifts the voltage dependence for activation of the heteromeric kv7.2/kv7.3 channel to more negative potentials, thus facilitating activation. although the molecular mechanism underlying retigabine's action remains unknown, previous studies have identified the pore region of kv7 channels as the drug's target. this suggested that the retigabine-induced shift in voltage dependence ... | 2016 | 26880756 |
| mrn, ctip, and brca1 mediate repair of topoisomerase ii-dna adducts. | repair of dna double-strand breaks (dsbs) with complex ends poses a special challenge, as additional processing is required before dna ligation. for example, protein-dna adducts must be removed to allow repair by either nonhomologous end joining or homology-directed repair. here, we investigated the processing of topoisomerase ii (top2)-dna adducts induced by treatment with the chemotherapeutic agent etoposide. through biochemical analysis in xenopus laevis egg extracts, we establish that the mr ... | 2016 | 26880199 |
| e-cadherin is required for cranial neural crest migration in xenopus laevis. | the cranial neural crest (cnc) is a highly motile and multipotent embryonic cell population, which migrates directionally on defined routes throughout the embryo, contributing to facial structures including cartilage, bone and ganglia. cadherin-mediated cell-cell adhesion is known to play a crucial role in the directional migration of cnc cells. however, migrating cnc co-express different cadherin subtypes, and their individual roles have yet to be fully explored. in previous studies, the expres ... | 2016 | 26879760 |
| direct interaction of the resistance to inhibitors of cholinesterase type 3 protein with the serotonin receptor type 3a intracellular domain. | pentameric ligand-gated ion channels (plgic) are expressed in both excitable and non-excitable cells that are targeted by numerous clinically used drugs. assembly from five identical or homologous subunits yields homo- or heteromeric pentamers, respectively. the protein known as resistance to inhibitors of cholinesterase (ric-3) was identified to interfere with assembly and functional maturation of plgics. we have shown previously for serotonin type 3a homopentamers (5-ht3a ) that the interactio ... | 2016 | 26875553 |
| sf3b4-depleted xenopus embryos: a model to study the pathogenesis of craniofacial defects in nager syndrome. | mandibulofacial dysostosis (mfd) is a human developmental disorder characterized by defects of the facial bones. it is the second most frequent craniofacial malformation after cleft lip and palate. nager syndrome combines many features of mfd with a variety of limb defects. mutations in sf3b4 (splicing factor 3b, subunit 4) gene, which encodes a component of the pre-mrna spliceosomal complex, were recently identified as a cause of nager syndrome, accounting for 60% of affected individuals. nothi ... | 2016 | 26874011 |
| cytosolic calcium transients are a determinant of contraction-induced hsp72 transcription in single skeletal muscle fibers. | the intrinsic activating factors that induce transcription of heat shock protein 72 (hsp72) in skeletal muscle following exercise remain unclear. we hypothesized that the cytosolic ca(2+) transient that occurs with depolarization is a determinant. we utilized intact, single skeletal muscle fibers from xenopus laevis to test the role of the cytosolic ca(2+) transient and several other exercise-related factors (fatigue, hypoxia, amp kinase, and cross-bridge cycling) on the activation of hsp72 tran ... | 2016 | 26869714 |
| carrier-mediated prodrug uptake to improve the oral bioavailability of polar drugs: an application to an oseltamivir analogue. | the goal of this study was to improve the intestinal mucosal cell membrane permeability of the poorly absorbed guanidino analogue of a neuraminidase inhibitor, oseltamivir carboxylate (goc) using a carrier-mediated strategy. valyl amino acid prodrug of goc with isopropyl-methylene-dioxy linker (goc-isp-val) was evaluated as the potential substrate for intestinal oligopeptide transporter, hpept1 in xenopus laevis oocytes heterologously expressing hpept1, and an intestinal mouse perfusion system. ... | 2016 | 26869437 |
| t-cell internal antigen 1 counteracts somatic rna degradation during early xenopus embryogenesis. | in xenopus laevis, maternal transcripts that localize to the vegetal cortex of the oocyte are specifically inherited by prospective germ cells during cleavage stages. while a large fraction of maternal transcripts is degraded during the maternal to zygotic transition (mzt), transcripts associated with the germ-line are stable. a sequence in the dead end 1 3'utr mediates vegetal localization in the oocyte as well as mir mediated clearance in somatic cells and germ cell specific stabilization duri ... | 2015 | 26864483 |
| bioelectric signalling via potassium channels: a mechanism for craniofacial dysmorphogenesis in kcnj2-associated andersen-tawil syndrome. | xenopus laevis craniofacial development is a good system for the study of andersen-tawil syndrome (ats)-associated craniofacial anomalies (cfas) because (1) kcnj2 is expressed in the nascent face; (2) molecular-genetic and biophysical techniques are available for the study of ion-dependent signalling during craniofacial morphogenesis; (3) as in humans, expression of variant kcnj2 forms in embryos causes a muscle phenotype; and (4) variant forms of kcnj2 found in human patients, when injected int ... | 2016 | 26864374 |
| stem cell-like xenopus embryonic explants to study early neural developmental features in vitro and in vivo. | understanding the genetic programs underlying neural development is an important goal of developmental and stem cell biology. in the amphibian blastula, cells from the roof of the blastocoel are pluripotent. these cells can be isolated, and programmed to generate various tissues through manipulation of genes expression or induction by morphogens. in this manuscript protocols are described for the use of xenopus laevis blastocoel roof explants as an assay system to investigate key in vivo and in ... | 2016 | 26863402 |
| tweaking subtype selectivity and agonist efficacy at (s)-2-amino-3-(3-hydroxy-5-methyl-isoxazol-4-yl)propionic acid (ampa) receptors in a small series of bntetampa analogues. | a series of analogues of the (s)-2-amino-3-(3-hydroxy-5-methyl-isoxazol-4-yl)propionic acid (ampa) receptor agonist bntetampa (5b) were synthesized and characterized pharmacologically in radioligand binding assays at native and cloned ampa receptors and functionally by two-electrode voltage clamp electrophysiology at the four homomeric ampa receptors expressed in xenopus laevis oocytes. the analogues 6 and 7 exhibit very different pharmacological profiles with binding affinity preference for the ... | 2016 | 26862980 |
| unequal contribution of native south african phylogeographic lineages to the invasion of the african clawed frog, xenopus laevis, in europe. | due to both deliberate and accidental introductions, invasive african clawed frog (xenopus laevis) populations have become established worldwide. in this study, we investigate the geographic origins of invasive x. laevis populations in france and portugal using the phylogeographic structure of x. laevis in its native south african range. in total, 80 individuals from the whole area known to be invaded in france and portugal were analysed for two mitochondrial and three nuclear genes, allowing a ... | 2016 | 26855879 |
| a three amino acid deletion in the transmembrane domain of the nicotinic acetylcholine receptor α6 subunit confers high-level resistance to spinosad in plutella xylostella. | spinosad is a macrocyclic lactone insecticide that acts primarily at the nicotinic acetylcholine receptors (nachrs) of target insects. here we describe evidence that high levels of resistance to spinosad in the diamondback moth (plutella xylostella) are associated with a three amino acid (3-aa) deletion in the fourth transmembrane domain (tm4) of the nachr α6 subunit (pxα6). following laboratory selection with spinosad, the sz-spinr strain of p. xylostella exhibited 940-fold resistance to spinos ... | 2016 | 26855198 |
| making muscle: morphogenetic movements and molecular mechanisms of myogenesis in xenopus laevis. | xenopus laevis offers unprecedented access to the intricacies of muscle development. the large, robust embryos make it ideal for manipulations at both the tissue and molecular level. in particular, this model system can be used to fate map early muscle progenitors, visualize cell behaviors associated with somitogenesis, and examine the role of signaling pathways that underlie induction, specification, and differentiation of muscle. several characteristics that are unique to x. laevis include myo ... | 2016 | 26853935 |
| using xenopus laevis retinal and spinal neurons to study mechanisms of axon guidance in vivo and in vitro. | the intricate and precise establishment of neuronal connections in the developing nervous system relies on accurate navigation of growing axons. since ramón y cajal's discovery of the growth cone, the phenomenon of axon guidance has been revealed as a coordinated operation of guidance molecules, receptors, secondary messengers, and responses driven by the dynamic cytoskeleton within the growth cone. with the advent of new and accelerating techniques, xenopus laevis emerged as a robust model to i ... | 2016 | 26853934 |
| heterologous expression of melanopsin: present, problems and prospects. | melanopsin, the photosensory pigment of specialized mammalian retinal ganglion cells, is involved in various non-image forming tasks such as pupillary light reflex, circadian entrainment and irradiance detection. melanopsin genes have been detected in all vertebrate classes and are resolved in two lineages, opn4m and opn4x. in addition, two splice variants have been found in several species leading to a short (opn4-s) and a long (opn4-l) isoform, mainly differing in the length of the c terminus. ... | 2016 | 26850932 |