Publications

TitleAbstractYear(sorted ascending)
Filter
PMID
Filter
asymmetries in cell division, cell size, and furrowing in the xenopus laevis embryo.asymmetric cell divisions produce two daughter cells with distinct fate. during embryogenesis, this mechanism is fundamental to build tissues and organs because it generates cell diversity. in adults, it remains crucial to maintain stem cells. the enthusiasm for asymmetric cell division is not only motivated by the beauty of the mechanism and the fundamental questions it raises, but has also very pragmatic reasons. indeed, misregulation of asymmetric cell divisions is believed to have dramatic c ...201728409308
asymmetric localization and distribution of factors determining cell fate during early development of xenopus laevis.asymmetric division is a property of eukaryotic cells that is fundamental to the formation of higher life forms. despite its importance, the mechanism behind it remains elusive. asymmetry in the cell is induced by polarization of cell fate determinants that become unevenly distributed among progeny cells. so far dozens of determinants have been identified. xenopus laevis is an ideal system to study asymmetric cell division during early development, because of the huge size of its oocytes and ear ...201728409307
chromosomal passenger complex hydrodynamics suggests chaperoning of the inactive state by nucleoplasmin/nucleophosmin.the chromosomal passenger complex (cpc) is a conserved, essential regulator of cell division. as such, significant anti-cancer drug development efforts have been focused on targeting it, most notably by inhibiting its aurkb kinase subunit. the cpc is activated by aurkb-catalyzed autophosphorylation on multiple subunits, but how this regulates cpc interactions with other mitotic proteins remains unclear. we investigated the hydrodynamic behavior of the cpc in xenopus laevis egg cytosol using sucr ...201728404751
masculinization-related genes and cell-mass structures during early gonadal differentiation in the african clawed frog xenopus laevis.the african clawed frog xenopus laevis has a female heterogametic zz/zw-type sex-determining system. we previously discovered a w-linked female sex-determining gene dm-w that is involved in ovary formation, probably through the up-regulation of the estrogen synthesis genes cyp19a1 and foxl2. we also reported that a unique "mass-in-line structure", which disappears from zz gonads during early testicular development, might serve as the basis for ovary differentiation in zw gonads. however, the mol ...201728397603
pattern of neurogenesis and identification of neuronal progenitor subtypes during pallial development in xenopus laevis.the complexity of the pallium during evolution has increased dramatically in many different respects. the highest level of complexity is found in mammals, where most of the pallium (cortex) shows a layered organization and neurons are generated during development following an inside-out order, a sequence not observed in other amniotes (birds and reptiles). species-differences may be related to major neurogenetic events, from the neural progenitors that divide and produce all pallial cells. in ma ...201728396626
the mgcracgap sxip motif tethers centralspindlin to microtubule plus ends in xenopus laevis.centralspindlin, a complex of the kinesin-6-family member mklp1 and mgcracgap (also known as kif23 and racgap1, respectively), is required for cytokinesis and cell-cell junctions. during anaphase, centralspindlin accumulates at overlapping central spindle microtubules and directs contractile ring formation by recruiting the gef ect2 to the cell equator to activate rhoa. we found that mgcracgap localized to the plus ends of equatorial astral microtubules during cytokinesis in xenopus laevis embry ...201728389580
clinical and genetic spectrum of bartter syndrome type 3.bartter syndrome type 3 is a clinically heterogeneous hereditary salt-losing tubulopathy caused by mutations of the chloride voltage-gated channel kb gene (clcnkb), which encodes the clc-kb chloride channel involved in nacl reabsorption in the renal tubule. to study phenotype/genotype correlations, we performed genetic analyses by direct sequencing and multiplex ligation-dependent probe amplification and retrospectively analyzed medical charts for 115 patients with clcnkb mutations. functional a ...201728381550
a dominant mutation in nuclear receptor interacting protein 1 causes urinary tract malformations via dysregulation of retinoic acid signaling.congenital anomalies of the kidney and urinary tract (cakut) are the most common cause of ckd in the first three decades of life. however, for most patients with cakut, the causative mutation remains unknown. we identified a kindred with an autosomal dominant form of cakut. by whole-exome sequencing, we identified a heterozygous truncating mutation (c.279delg, p.trp93fs*) of the nuclear receptor interacting protein 1 gene (nrip1) in all seven affected members. nrip1 encodes a nuclear receptor tr ...201728381549
multiple origins of embryonic and tadpole myeloid cells in xenopus laevis.rabbit anti-serum against a myeloid-cell-specific peroxidase (mpo) of xenopus laevis was generated to identify myeloid cells in adult and larval animals. smears of blood samples from adult hematopoietic organs were co-stained with mpo and with xl-2, a mouse monoclonal antibody against a leukocyte common antigen. lymphocytes found in the thymus and spleen were xl-2+mpo- and granulocytes found in peripheral blood cells and the spleen were xl-2+mpo+, indicating that double-staining with these two a ...201728374149
upregulation of matrix metalloproteinase triggers transdifferentiation of retinal pigmented epithelial cells in xenopus laevis: a link between inflammatory response and regeneration.in adult xenopus eyes, when the whole retina is removed, retinal pigmented epithelial (rpe) cells become activated to be retinal stem cells and regenerate the whole retina. in the present study, using a tissue culture model, it was examined whether upregulation of matrix metalloproteinases (mmps) triggers retinal regeneration. soon after retinal removal, xmmp9 and xmmp18 were strongly upregulated in the tissues of the rpe and the choroid. in the culture, mmp expression in the rpe cells correspon ...201728371543
population-specific resequencing associates the atp-binding cassette subfamily c member 4 gene with gout in new zealand māori and pacific men.there is no evidence for a genetic association between organic anion transporters 1-3 (slc22a6, slc22a7, and slc22a8) and multidrug resistance protein 4 (mrp4; encoded by abcc4) with the levels of serum urate or gout. the māori and pacific (polynesian) population of new zealand has the highest prevalence of gout worldwide. the aim of this study was to determine whether any polynesian population-specific genetic variants in slc22a6-8 and abcc4 are associated with gout.201728371506
interaction and developmental activation of two neuroendocrine systems that regulate light-mediated skin pigmentation.lower vertebrates use rapid light-regulated changes in skin colour for camouflage (background adaptation) or during circadian variation in irradiance levels. two neuroendocrine systems, the eye/alpha-melanocyte-stimulating hormone (α-msh) and the pineal complex/melatonin circuits, regulate the process through their respective dispersion and aggregation of pigment granules (melanosomes) in skin melanophores. during development, xenopus laevis tadpoles raised on a black background or in the dark p ...201728371026
cul-2lrr-1 and ubxn-3 drive replisome disassembly during dna replication termination and mitosis.replisome disassembly is the final step of dna replication in eukaryotes, involving the ubiquitylation and cdc48-dependent dissolution of the cmg helicase (cdc45-mcm-gins). using caenorhabditis elegans early embryos and xenopus laevis egg extracts, we show that the e3 ligase cul-2lrr-1 associates with the replisome and drives ubiquitylation and disassembly of cmg, together with the cdc-48 cofactors ufd-1 and npl-4. removal of cmg from chromatin in frog egg extracts requires cul2 neddylation, and ...201728368371
xenopus metamorphosis as a model to study thyroid hormone receptor function during vertebrate developmental transitions.a hormone-dependent developmental transition from aquatic to terrestrial existence occurs in all tetrapod vertebrates, such as birth, hatching, and metamorphosis. thyroid hormones (th) and their receptors (trs) are key players in the tissue transformations comprising vertebrate developmental transitions. the african clawed frog, xenopus, is a premier model for the role of trs in developmental transitions because of the numerous and dramatic th-dependent tissue transformations during metamorphosi ...201728363743
asymmetrically reduced expression of hand1 homeologs involving a single nucleotide substitution in a cis-regulatory element.during vertebrate evolution, whole genome duplications resulted in a number of duplicated genes, some of which eventually changed their expression patterns and/or levels via alteration of cis-regulatory sequences. however, the initial process involved in such cis-regulatory changes remains unclear. therefore, we investigated this process by analyzing the duplicated hand1 genes of xenopus laevis (hand1.l and hand1.s), which were generated by allotetraploidization 17-18 million years ago, and comp ...201728359808
the heterochronic gene lin28 regulates amphibian metamorphosis through disturbance of thyroid hormone function.metamorphosis is a classic example of developmental transition, which involves important morphological and physiological changes that prepare the organism for the adult life. it has been very well established that amphibian metamorphosis is mainly controlled by thyroid hormone (th). here, we show that the heterochronic gene lin28 is downregulated during xenopus laevis metamorphosis. lin28 overexpression before activation of th signaling delays metamorphosis and inhibits the expression of th targ ...201728359807
paxillin and embryonic polyadenylation binding protein (epabp) engage to regulate androgen-dependent xenopus laevis oocyte maturation - a model of kinase-dependent regulation of protein expression.steroid-triggered xenopus laevis oocyte maturation is an elegant physiologic model of nongenomic steroid signaling, as it proceeds completely independent of transcription. we previously demonstrated that androgens are the main physiologic stimulator of oocyte maturation in xenopus oocytes, and that the adaptor protein paxillin plays a crucial role in mediating this process through a positive feedback loop in which paxillin first enhances mos protein translation, ensued by erk2 activation and erk ...201728359799
pkc-mediated phosphorylation of nuclear lamins at a single serine residue regulates interphase nuclear size in xenopus and mammalian cells.how nuclear size is regulated is a fundamental cell-biological question with relevance to cancers, which often exhibit enlarged nuclei. we previously reported that conventional protein kinase c (cpkc) contributes to nuclear size reductions that occur during early xenopus development. here we report that pkc-mediated phosphorylation of lamin b3 (lb3) contributes to this mechanism of nuclear size regulation. by mapping pkc phosphorylation sites on lb3 and testing the effects of phosphomutants in x ...201728356420
spemann organizer transcriptome induction by early beta-catenin, wnt, nodal, and siamois signals in xenopus laevis.the earliest event in xenopus development is the dorsal accumulation of nuclear β-catenin under the influence of cytoplasmic determinants displaced by fertilization. in this study, a genome-wide approach was used to examine transcription of the 43,673 genes annotated in the xenopus laevis genome under a variety of conditions that inhibit or promote formation of the spemann organizer signaling center. loss of function of β-catenin with antisense morpholinos reproducibly reduced the expression of ...201728348214
osptr7 (osnpf8.1), a putative peptide transporter in rice, is involved in dimethylarsenate accumulation in rice grain.rice (oryza sativa) is a major dietary source of arsenic (as) for the population consuming rice as their staple food. rice grain contains both inorganic as and methylated as species, especially dimethyarsinate (dma). dma is highly mobile in long-distance translocation in plants, but the underlying mechanism remains unknown. in the present study, we showed that osptr7 (osnpf8.1), a putative peptide transporter in rice, was permeable to dma in xenopus laevis oocytes. transient expression of the os ...201728340032
glycans in the intestinal peptide transporter pept1 contribute to function and protect from proteolysis.despite the fact that many membrane proteins carry extracellular glycans, little is known about whether the glycan chains also affect protein function. we recently demonstrated that the proton-coupled oligopeptide transporter 1 (pept1) in the intestine is glycosylated at six asparagine residues (n50, n406, n439, n510, n515, and n532). mutagenesis-induced disruption of the individual n-glycosylation site n50, which is highly conserved among mammals, was detected to significantly enhance the pept1 ...201728336547
the modulation of two motor behaviors by persistent sodium currents in xenopus laevis tadpoles.persistent sodium currents (inap) are common in neuronal circuitries and have been implicated in several diseases, such as amyotrophic lateral sclerosis (als) and epilepsy. however, the role of inap in the regulation of specific behaviors is still poorly understood. in this study we have characterized inap and investigated its role in the swimming and struggling behavior of xenopus tadpoles. inap was identified in three groups of neurons, namely, sensory rohon-beard neurons (rb neurons), descend ...201728331009
actomyosin-generated tension on cadherin is similar between dividing and non-dividing epithelial cells in early xenopus laevis embryos.epithelia represent a unique situation where polarized cells must maintain sufficiently strong cell-cell contacts to guarantee the epithelial integrity indispensable for barrier functions. nevertheless, epithelia must also keep sufficient plasticity which is crucial during development and morphogenesis. adherens junctions and mechanical forces produced by the actomyosin cytoskeleton are major players for epithelial integrity maintenance and plasticity regulations. to understand how the epitheliu ...201728327558
direct regulation of histidine ammonia-lyase 2 gene by thyroid hormone in the developing adult intestinal stem cells.most vertebrate organs use adult stem cells to maintain homeostasis and ensure proper repair when damaged. how such organ-specific stem cells are formed during vertebrate development is largely unexplored. we have been using the thyroid hormone (t3)-dependent amphibian metamorphosis to address this issue. early studies in xenopus laevis have shown that intestinal remodeling involves complete degeneration of the larval epithelium and de novo formation of adult stem cells through dedifferentiation ...201728323994
sall1 and sall4 repress pou5f3 family expression to allow neural patterning, differentiation, and morphogenesis in xenopus laevis.the embryonic precursor of the vertebrate central nervous system, the neural plate, is patterned along the anterior-posterior axis and shaped by morphogenetic movements early in development. we previously identified the genes sall1 and sall4, known regulators of pluripotency in other contexts, as transcriptional targets of developmental signaling pathways that regulate neural development. here, we demonstrate that these two genes are required for induction of posterior neural fates, the cell sha ...201728322736
teratogenic hazard of bpei-coated silver nanoparticles to xenopus laevis.silver nanoparticles (agnps) are among the most exploited antimicrobial agents and are used in many consumer products. size and surface reactivity are critical physico-chemical properties responsible for nps toxicity, and surface coatings, often used to functionalize or stabilize agnps, can influence their toxic profile and biocompatibility. in the current study the developmental toxicity of (1) negatively charged citrate-coated agnps (cit-agnps), (2) positively charged branched polyethylenimine ...201728318347
jak-stat pathway activation in response to spinal cord injury in regenerative and non-regenerative stages of xenopus laevis.xenopus laevis tadpoles can regenerate the spinal cord after injury but this capability is lost during metamorphosis. comparative studies between pre-metamorphic and metamorphic xenopus stages can aid towards understanding the molecular mechanisms of spinal cord regeneration. analysis of a previous transcriptome-wide study suggests that, in response to injury, the jak-stat pathway is differentially activated in regenerative and non-regenerative stages. we characterized the activation of the jak- ...201728316792
a cellular mechanism for inverse effectiveness in multisensory integration.to build a coherent view of the external world, an organism needs to integrate multiple types of sensory information from different sources, a process known as multisensory integration (msi). previously, we showed that the temporal dependence of msi in the optic tectum of xenopus laevis tadpoles is mediated by the network dynamics of the recruitment of local inhibition by sensory input (felch et al., 2016). this was one of the first cellular-level mechanisms described for msi. here, we expand th ...201728315524
novel short antimicrobial peptide isolated from xenopus laevis skin.a rich source of bioactive peptides, including a large number of antimicrobial peptides, has been found in amphibian skin. in this study, a novel short antimicrobial peptide was purified from xenopus laevis skin and characterised through reversed-phase high-performance liquid chromatography, edman degradation and matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry. the peptide was composed of six amino acids with a sequence of dedlde and thus named x. laevis antibacteria ...201728299865
when size matters: transient receptor potential vanilloid 4 channel as a volume-sensor rather than an osmo-sensor.mammalian cells are frequently exposed to stressors causing volume changes. the transient receptor potential vanilloid 4 (trpv4) channel translates osmotic stress into ion flux. the molecular mechanism coupling osmolarity to trpv4 activation remains elusive. trpv4 responds to isosmolar cell swelling and osmolarity translated via different aquaporins. trpv4 functions as a volume-sensing ion channel irrespective of the origin of the cell swelling.201728295351
functional organization of vestibulo-ocular responses in abducens motoneurons.vestibulo-ocular reflexes (vors) are the dominating contributors to gaze stabilization in all vertebrates. during horizontal head movements, abducens motoneurons form the final element of the reflex arc that integrates visuovestibular inputs into temporally precise motor commands for the lateral rectus eye muscle. here, we studied a possible differentiation of abducens motoneurons into subtypes by evaluating their morphology, discharge properties, and synaptic pharmacology in semi-intact in vitr ...201728292832
transcriptomic insights into genetic diversity of protein-coding genes in x. laevis.we characterize the genetic diversity of xenopus laevis strains using rna-seq data and allele-specific analysis. this data provides a catalogue of coding variation, which can be used for improving the genomic sequence, as well as for better sequence alignment, probe design, and proteomic analysis. in addition, we paint a broad picture of the genetic landscape of the species by functionally annotating different classes of mutations with a well-established prediction tool (polyphen-2). further, we ...201728283406
persistent fibrosis, hypertrophy and sarcomere disorganisation after endoscopy-guided heart resection in adult xenopus.models of cardiac repair are needed to understand mechanisms underlying failure to regenerate in human cardiac tissue. such studies are currently dominated by the use of zebrafish and mice. remarkably, it is between these two evolutionary separated species that the adult cardiac regenerative capacity is thought to be lost, but causes of this difference remain largely unknown. amphibians, evolutionary positioned between these two models, are of particular interest to help fill this lack of knowle ...201728278282
spinal cord cells from pre-metamorphic stages differentiate into neurons and promote axon growth and regeneration after transplantation into the injured spinal cord of non-regenerative xenopus laevis froglets.mammals are unable to regenerate its spinal cord after a lesion, meanwhile, anuran amphibians are capable of spinal cord regeneration only as larvae, and during metamorphosis, this capability is lost. sox2/3+ cells present in the spinal cord of regenerative larvae are required for spinal cord regeneration. here we evaluate the effect of the transplantation of spinal cord cells from regenerative larvae into the resected spinal cord of non-regenerative stages (nr-stage). donor cells were able to s ...201729326551
microprobe capillary electrophoresis mass spectrometry for single-cell metabolomics in live frog (xenopus laevis) embryos.the quantification of small molecules in single cells raises new potentials for better understanding the basic processes that underlie embryonic development. to enable single-cell investigations directly in live embryos, new analytical approaches are needed, particularly those that are sensitive, selective, quantitative, robust, and scalable to different cell sizes. here, we present a protocol that enables the in situ analysis of metabolism in single cells in freely developing embryos of the sou ...201729286491
a glyphosate micro-emulsion formulation displays teratogenicity in xenopus laevis.glyphosate is the active ingredient in broad-spectrum herbicide formulations used in agriculture, domestic area and aquatic weed control worldwide. its market is growing steadily concurrently with the cultivation of glyphosate-tolerant transgenic crops and emergence of weeds less sensitive to glyphosate. ephemeral and lentic waters near to agricultural lands, representing favorite habitats for amphibian reproduction and early life-stage development, may thus be contaminated by glyphosate based h ...201729306033
bioelectric regulation of innate immune system function in regenerating and intact xenopus laevis.two key inputs that regulate regeneration are the function of the immune system, and spatial gradients of transmembrane potential (vmem). endogenous bioelectric signaling in somatic tissues during regenerative patterning is beginning to be understood, but its role in the context of immune response has never been investigated. here, we show that vmem levels modulate innate immunity activity in xenopus laevis embryos. we developed an assay in which x. laevis embryos are infected with a uropathogen ...201729302351
quantitative comparative analysis of the nasal chemosensory organs of anurans during larval development and metamorphosis highlights the relative importance of chemosensory subsystems in the group.the anuran peripheral olfactory system is composed of a number of subsystems, represented by distinct neuroepithelia. these include the main olfactory epithelium and vomeronasal organ (found in most tetrapods) and three specialized epithelia of anurans: the buccal-exposed olfactory epithelium of larvae, and the olfactory recess and middle chamber epithelium of postmetamorphic animals. to better characterize the developmental changes in these subsystems across the life cycle, morphometric changes ...201728503895
differences in mobility at the range edge of an expanding invasive population of xenopus laevis in the west of france.theoretical models predict that spatial sorting at the range edge of expanding populations should favor individuals with increased mobility relative to individuals at the center of the range. despite the fact that empirical evidence for the evolution of locomotor performance at the range edge is rare, data on cane toads support this model. however, whether this can be generalized to other species remains largely unknown. here, we provide data on locomotor stamina and limb morphology in individua ...201728100805
competition and feeding ecology in two sympatric xenopus species (anura: pipidae).the widespread african clawed frog (xenopus laevis) occurs in sympatry with the iucn endangered cape platanna (xenopus gilli) throughout its entire range in the south-western cape, south africa. in order to investigate aspects of the interspecific competition between populations of x. laevis and x. gilli, an assessment of their niche differentiation was conducted through a comprehensive study on food composition and trophic niche structure at two study sites: the cape of good hope (cogh) and kle ...201728439453
limited genomic consequences of hybridization between two african clawed frogs, xenopus gilli and x. laevis (anura: pipidae).the cape platanna, xenopus gilli, an endangered frog, hybridizes with the african clawed frog, x. laevis, in south africa. estimates of the extent of gene flow between these species range from pervasive to rare. efforts have been made in the last 30 years to minimize hybridization between these two species in the west population of x. gilli, but not the east populations. to further explore the impact of hybridization and the efforts to minimize it, we examined molecular variation in one mitochon ...201728439068
chromosome divergence during evolution of the tetraploid clawed frogs, xenopus mellotropicalis and xenopus epitropicalis as revealed by zoo-fish.whole genome duplication (wgd) generates new species and genomic redundancy. in african clawed frogs of the genus xenopus, this phenomenon has been especially important in that (i) all but one extant species are polyploid and (ii) whole genome sequences of some species provide an evidence for genomic rearrangements prior to or after wgd. within xenopus in the subgenus silurana, at least one allotetraploidization event gave rise to three extant tetraploid (2n = 4x = 40) species-xenopus mellotropi ...201728545147
biophysical characterization of genetically encoded voltage sensor asap1: dynamic range improvement.recent work has introduced a new fluorescent voltage sensor, asap1, which can monitor rapid trains of action potentials in cultured neurons. this indicator is based on the gallus gallus voltage-sensitive phosphatase with the phosphatase domain removed and a circularly permuted gfp placed in the s3-s4 linker. however, many of the biophysical details of this indicator remain unknown. in this work, we study the biophysical properties of asap1. using the cut-open voltage clamp technique, we have sim ...201729108650
influence of the rdl a301s mutation in the brown planthopper nilaparvata lugens on the activity of phenylpyrazole insecticides.we discovered the a301s mutation in the rdl gaba-gated chloride channel of fiprole resistant rice brown planthopper, nilaparvata lugens populations by dna sequencing and snp calling via rnaseq. ethiprole selection of two field n. lugens populations resulted in strong resistance to both ethiprole and fipronil and resulted in fixation of the a301s mutation, as well as the emergence of another mutation, q359e in one of the selected strains. to analyse the roles of these mutations in resistance to p ...201729107231
identification of novel cis-regulatory elements of eya1 in xenopus laevis using bac recombineering.the multifunctional eya1 protein plays important roles during the development of cranial sensory organs and ganglia, kidneys, hypaxial muscles and several other organs in vertebrates. eya1 is encoded by a complex locus with candidate cis-regulatory elements distributed over a 329 kbp wide genomic region in xenopus. consequently, very little is currently known about how expression of eya1 is controlled by upstream regulators. here we use a library of xenopus tropicalis genomic sequences in bacter ...201729101371
frizzled-7 is required for xenopus heart development.wnt signalling regulates cardiogenesis during specification of heart tissue and the morphogenetic movements necessary to form the linear heart. wnt11-mediated non-canonical signalling promotes early cardiac development whilst wnt11-r, which is expressed later, also signals through the non-canonical pathway to promote heart development. it is unclear which frizzled proteins mediate these interactions. frizzled-7 (fzd7) is expressed during gastrulation in the mesodermal cells fated to become heart ...201729101100
4-aminopyridine: a pan voltage-gated potassium channel inhibitor that enhances kv 7.4 currents and inhibits noradrenaline-mediated contraction of rat mesenteric small arteries.kv 7.4 and kv 7.5 channels are regulators of vascular tone. 4-aminopyridine (4-ap) is considered a broad inhibitor of voltage-gated potassium (kv ) channels, with little inhibitory effect on kv 7 family members at mmol concentrations. however, the effect of 4-ap on kv 7 channels has not been systematically studied. the aim of this study was to investigate the pharmacological activity of 4-ap on kv 7.4 and kv 7.5 channels and characterize the effect of 4-ap on rat resistance arteries.201729156097
a nonredundant role for the trpm6 channel in neural tube closure.in humans, germline mutations in trpm6 cause autosomal dominant hypomagnesemia with secondary hypocalcemia disorder. loss of trpm6 in mice also perturbs cellular magnesium homeostasis but additionally results in early embryonic lethality and neural tube closure defects. to define the mechanisms by which trpm6 influences neural tube closure, we functionally characterized the role of trpm6 during early embryogenesis in xenopus laevis. the expression of xenopus trpm6 (xtrpm6) is elevated at the ons ...201729142255
developmental changes in spinal neuronal properties, motor network configuration and neuromodulation at free-swimming stages of xenopus frog tadpoles.we describe a novel preparation of the isolated brainstem and spinal cord from pro-metamorphic tadpole stages of the south african clawed frog (xenopus laevis) that permits whole cell patch-clamp recordings from neurons in the ventral spinal cord. previous research on earlier stages of the same species has provided one of the most detailed understandings of the design and operation of a cpg circuit. here we have addressed how development sculpts complexity from this more basic circuit. the prepa ...201729142093
it's not all black and white: visual scene parameters influence optokinetic reflex performance in xenopus laevis tadpoles.the maintenance of visual acuity during active and passive body motion is ensured by gaze-stabilizing reflexes that aim at minimizing retinal image slip. for the optokinetic reflex (okr), large-field visual motion of the surround forms the essential stimulus that activates eye movements. properties of the moving visual world influence cognitive motion perception and the estimation of visual image velocity. therefore, the performance of brainstem-mediated visuo-motor behaviors might also depend o ...201729141881
overland movement in african clawed frogs (xenopus laevis): empirical dispersal data from within their native range.dispersal forms are an important component of the ecology of many animals, and reach particular importance for predicting ranges of invasive species. african clawed frogs (xenopus laevis) move overland between water bodies, but all empirical studies are from invasive populations with none from their native southern africa. here we report on incidents of overland movement found through a capture-recapture study carried out over a three year period in overstrand, south africa. the maximum distance ...201729134157
specific inhibition of gpcr-independent g protein signaling by a rationally engineered protein.activation of heterotrimeric g proteins by cytoplasmic nonreceptor proteins is an alternative to the classical mechanism via g protein-coupled receptors (gpcrs). a subset of nonreceptor g protein activators is characterized by a conserved sequence named the gα-binding and activating (gba) motif, which confers guanine nucleotide exchange factor (gef) activity in vitro and promotes g protein-dependent signaling in cells. gba proteins have important roles in physiology and disease but remain greatl ...201729133411
towards functional selectivity for α6β3γ2 gabaa receptors: a series of novel pyrazoloquinolinones.the gabaa receptors are ligand-gated ion channels, which play an important role in neurotransmission. their variety of binding sites serves as an appealing target for many clinically relevant drugs. here, we explored the functional selectivity of modulatory effects at specific extracellular α+/β- interfaces, using a systematically varied series of pyrazoloquinolinones.201729127702
wall following in xenopus laevis is barrier-driven.the tendency of animals to follow boundaries within their environment can serve as a strategy for spatial learning or defensive behaviour. we examined whether xenopus laevis tadpoles and froglets employ such a strategy by characterizing their swimming pattern in a square tank with shallow water. trajectories obtained from video recordings were analysed for proximity to the nearest wall. with the exception of young larvae, the vast majority of animals (both tadpoles and froglets) spent a dispropo ...201729119247
nuclear pore complex plasticity during developmental process as revealed by super-resolution microscopy.nuclear pore complex (npc) is of paramount importance for cellular processes since it is the unique gateway for molecular exchange through the nucleus. unraveling the modifications of the npc structure in response to physiological cues, also called nuclear pore plasticity, is key to the understanding of the selectivity of this molecular machinery. as a step towards this goal, we use the optical super-resolution microscopy method called direct stochastic optical reconstruction microscopy (dstorm) ...201729116248
the rice high-affinity k+ transporter oshkt2;4 mediates mg2+ homeostasis under high-mg2+ conditions in transgenic arabidopsis.rice (oryza sativa; background nipponbare) contains nine hkt (high-affinity k+ transport)-like genes encoding membrane proteins belonging to the superfamily of ktr/trk/hkt. oshkts have been proposed to include four selectivity filter-pore-forming domains homologous to the bacterial k+ channel kcsa, and are separated into oshkt1s with na+-selective activity and oshkt2s with na+-k+ symport activity. as a member of the oshkt2 subfamily, oshkt2;4 renders mg2+ and ca2+ permeability for yeast cells an ...201729114257
xenopus laevis as a model organism for the study of spinal cord formation, development, function and regeneration.the spinal cord is the first central nervous system structure to develop during vertebrate embryogenesis, underscoring its importance to the organism. because of its early formation, accessibility to the developing spinal cord in amniotes is challenging, often invasive and the experimental approaches amenable to model systems like mammals are limited. in contrast, amphibians, in general and the african-clawed frog xenopus laevis, in particular, offer model systems in which the formation of the s ...201729218002
interaction of purinergic p2x4 and p2x7 receptor subunits.p2x4 and p2x7 are members of the p2x receptor family, comprising seven isoforms (p2x1-p2x7) that form homo- and heterotrimeric non-specific cation channels gated by extracellular atp. p2x4 and p2x7 are widely coexpressed, particularly in secretory epithelial cells and immune and inflammatory cells, and regulate inflammation and nociception. although functional heteromerization has been established for p2x2 and p2x3 subunits expressed in sensory neurons, there are contradictory reports regarding ...201729213241
spindle-to-cortex communication in cleaving frog eggs.during cytokinesis, the mitotic spindle communicates with the cell cortex to position a cleavage furrow that will cut through the cell in the plane defined by the metaphase plate. we investigated the molecular basis of this communication in xenopus laevis eggs, where the signal has to travel ∼400 µm in ∼30 min to reach the cortex from the first anaphase spindle. at anaphase onset, huge microtubule asters grow out from the poles of the spindle and meet at the plane previously defined by the metap ...201729196560
the ectodomain of cadherin-11 binds to erbb2 and stimulates akt phosphorylation to promote cranial neural crest cell migration.during development, a multi-potent group of cells known as the cranial neural crest (cnc) migrate to form craniofacial structures. proper migration of these cells requires proteolysis of cell adhesion molecules, such as cadherins. in xenopus laevis, preventing extracellular cleavage of cadherin-11 impairs cnc migration. however, overexpression of the soluble cleavage product (ec1-3) is capable of rescuing this phenotype. the mechanism by which ec1-3 promotes cnc migration has not been investigat ...201729190819
tissue-specific gene inactivation in xenopus laevis: knockout of lhx1 in the kidney with crispr/cas9.studying genes involved in organogenesis is often difficult because many of these genes are also essential for early development. the allotetraploid frog, xenopus laevis, is commonly used to study developmental processes, but because of the presence of two homeologs for many genes, it has been difficult to use as a genetic model. few studies have successfully used crispr in amphibians, and currently there is no tissue-targeted knockout strategy described in xenopus the goal of this study is to d ...201729187504
evaluating the longevity of surgically extracted xenopus laevis oocytes for the study of nematode ligand-gated ion channels.xenopus laevis oocytes have been extensively used as a heterologous expression system for the study of ion channels. while used successfully worldwide as tool for expressing and characterizing ion channels from a wide range of species, the limited longevity of oocytes once removed from the animal can pose significant challenges. in this study, we evaluate a simple and useful method that extends the longevity of xenopus oocytes after removal from the animal and quantitatively assessed the reliabi ...201729185074
quantification of size effect on protein rotational mobility in cells by 19f nmr spectroscopy.protein diffusion in living cells might differ significantly from that measured in vitro. little is known about the effect of globular protein size on rotational diffusion in cells because each protein has distinct surface properties, which result in different interactions with cellular components. to overcome this problem, the b1 domain of protein g (gb1) and several concatemers of the protein were labeled with 5-fluorotryptophan and studied by 19f nmr in escherichia coli cells, xenopus laevis ...201729184995
the r81t mutation in the nicotinic acetylcholine receptor of aphis gossypii is associated with neonicotinoid insecticide resistance with differential effects for cyano- and nitro-substituted neonicotinoids.the cotton aphid, aphis gossypii glover, is one of the most agriculturally important insect pests. neonicotinoid insecticides and sulfoxaflor have generally shown excellent control of a. gossypii, but these aphids have recently developed resistance against neonicotinoid insecticides. we previously characterized a field-collected a. gossypii kushima clone that showed higher resistance to nitro-substituted neonicotinoids, such as imidacloprid, than to cyano-substituted neonicotinoids, such as acet ...201729183611
targeted base editing via rna-guided cytidine deaminases in xenopus laevis embryos.genome editing using programmable nucleases such as crispr/cas9 or cpf1 has emerged as powerful tools for gene knock-out or knock-in in various organisms. while most genetic diseases are caused by point mutations, these genome-editing approaches are inefficient in inducing single-nucleotide substitutions. recently, cas9-linked cytidine deaminases, named base editors (bes), have been shown to convert cytidine to uridine efficiently, leading to targeted single-base pair substitutions in human cell ...201729179261
rnas coordinate nuclear envelope assembly and dna replication through elys recruitment to chromatin.upon fertilisation, the sperm pronucleus acquires the competence to replicate the genome through a cascade of events that link chromatin remodelling to nuclear envelope formation. the factors involved have been partially identified and are poorly characterised. here, using xenopus laevis egg extracts we show that rnas are required for proper nuclear envelope assembly following sperm dna decondensation. although chromatin remodelling and pre-replication complex formation occur normally, rna-deple ...201729242643
functional reintegration of sensory neurons and transitional dendritic reduction of mitral/tufted cells during injury-induced recovery of the larval xenopus olfactory circuit.understanding the mechanisms involved in maintaining lifelong neurogenesis has a clear biological and clinical interest. in the present study, we performed olfactory nerve transection on larval xenopus to induce severe damage to the olfactory circuitry. we surveyed the timing of the degeneration, subsequent rewiring and functional regeneration of the olfactory system following injury. a range of structural labeling techniques and functional calcium imaging were performed on both tissue slices an ...201729234276
the human dna glycosylases neil1 and neil3 excise psoralen-induced dna-dna cross-links in a four-stranded dna structure.interstrand cross-links (icls) are highly cytotoxic dna lesions that block dna replication and transcription by preventing strand separation. previously, we demonstrated that the bacterial and human dna glycosylases nei and neil1 excise unhooked psoralen-derived icls in three-stranded dna via hydrolysis of the glycosidic bond between the crosslinked base and deoxyribose sugar. furthermore, neil3 from xenopus laevis has been shown to cleave psoralen- and abasic site-induced icls in xenopus egg ex ...201729234069
antagonistic effect of dopamine structural analogues on human gabaρ1 receptor.gabaergic and dopaminergic pathways are co-localized in several areas of the central nervous system and recently several reports have shown co-release of both neurotransmitters. the gaba-a receptor (β and ρ1 subunits) is modulated by dopamine (da) and, interestingly, gabaρ1 can be modulated by several biogenic amines. here we explored the effects of the metabolites of the dopaminergic pathway and other structural analogues of da on gabaρ1 and the da gated ion channel (lgc-53) from caenorhabditis ...201729234054
increasing the length and hydrophobicity of the c-terminal sequence of transthyretin strengthens its binding affinity to retinol binding protein.transthyretin (ttr) is a transporter for thyroid hormone (th) and retinol, the latter via binding with retinol binding protein (rbp). both the n-terminal and c-terminal regions of the ttr subunit are located in close proximity to the central binding channel for ligands. during the evolution of vertebrates, these regions changed in length and hydropathy. the changes in the n-terminal sequence were demonstrated to affect the binding affinities for ths and rbp. here, the effects of changes in the c ...201729226076
species specific rna a-to-i editing of mosquito rdl modulates gaba potency and influences agonistic, potentiating and antagonistic actions of ivermectin.the insect gaba receptor, rdl, is the target of several classes of pesticides. the peptide sequences of rdl are generally highly conserved between diverse insects. however, rna a-to-i editing can effectively alter amino acid residues of rdl in a species specific manner, which can affect the potency of gaba and possibly insecticides. we report here that rna a-to-i editing alters the gene products of rdl in three mosquito disease vectors, recoding five amino acid residues in rdl of aedes aegypti a ...201729223796
rna helicase mov10 is essential for gastrulation and cns development.mov10 is an rna helicase that modulates access of argonaute 2 to microrna recognition elements in mrnas. we examined the role of mov10 in xenopus laevis development and show a critical role for mov10 in gastrulation and in the development of the central nervous system.201729266590
dynamic intramolecular regulation of the histone chaperone nucleoplasmin controls histone binding and release.nucleoplasmin (npm) is a highly conserved histone chaperone responsible for the maternal storage and zygotic release of histones h2a/h2b. npm contains a pentameric n-terminal core domain and an intrinsically disordered c-terminal tail domain. though intrinsically disordered regions are common among histone chaperones, their roles in histone binding and chaperoning remain unclear. using an nmr-based approach, here we demonstrate that the xenopus laevis npm tail domain controls the binding of hist ...201729263320
differentiation-dependent antiviral capacities of amphibian (xenopus laevis) macrophages.infections by ranaviruses such as frog virus 3 (fv3) are significantly contributing to the worldwide amphibian population declines. notably, amphibian macrophages (mφs) are important to both the fv3 infection strategies and the immune defense against this pathogen. however, the mechanisms underlying amphibian mφ fv3 susceptibility and resistance remain unknown. mφ differentiation is mediated by signaling through the colony-stimulating factor-1 receptor (csf-1r), which is now known to be bound by ...201729259133
tight junctions negatively regulate mechanical forces applied to adherens junctions in vertebrate epithelial tissue.epithelia are layers of polarised cells tightly bound to each other by adhesive contacts. epithelia act as barriers between an organism and its external environment. understanding how epithelia maintain their essential integrity while remaining sufficiently plastic to allow events such as cytokinesis to take place is a key biological problem. in vertebrates, the remodelling and reinforcement of adherens junctions maintains epithelial integrity during cytokinesis. the involvement of tight junctio ...201729246943
apetx4, a novel sea anemone toxin and a modulator of the cancer-relevant potassium channel kv10.1.the human ether-à-go-go channel (heag1 or kv10.1) is a cancer-relevant voltage-gated potassium channel that is overexpressed in a majority of human tumors. peptides that are able to selectively inhibit this channel can be lead compounds in the search for new anticancer drugs. here, we report the activity-guided purification and electrophysiological characterization of a novel kv10.1 inhibitor from the sea anemone anthopleura elegantissima. purified sea anemone fractions were screened for inhibit ...201728902151
depolarization of the conductance-voltage relationship in the nav1.5 mutant, e1784k, is due to altered fast inactivation.e1784k is the most common mixed long qt syndrome/brugada syndrome mutant in the cardiac voltage-gated sodium channel nav1.5. e1784k shifts the midpoint of the channel conductance-voltage relationship to more depolarized membrane potentials and accelerates the rate of channel fast inactivation. the depolarizing shift in the midpoint of the conductance curve in e1784k is exacerbated by low extracellular ph. we tested whether the e1784k mutant shifts the channel conductance curve to more depolarize ...201728898267
the effect of 4-hydroxybenzaldehyde on the γ-aminobutyric acid type a receptor.the α1β2γ2 subtype of gabaa receptors is the most commonly found gabaa receptor subtype in the mammalian cortex and hippocampus. it is expressed heterologously in the xenopus laevis oocyte as a α1β2γ2s/l subtype for application as an in vitro model for the screening of compounds that modulate receptor activities. in fact, 4-hydroxybenzaldehyde (4-hb) has been identified as one of the major components in dendrocalamus asper bamboo shoots in our previous study, and the current study showed that at ...201728894409
ultrafast flavin photoreduction in an oxidized animal (6-4) photolyase through an unconventional tryptophan tetrad.photolyases are flavoenzymes repairing uv-induced lesions in dna, which may be activated by a photoreduction of their fad cofactor. in most photolyases, this photoreduction proceeds by electron transfer along a chain of three tryptophan (trp) residues, connecting the flavin to the protein surface. much less studied, animal (6-4) photolyases (repairing pyrimidine-pyrimidone (6-4) photoproducts) are particularly interesting as they were recently shown to have a longer electron transfer chain, coun ...201728890968
sumo co-expression modifies kv 11.1 channel activity.the voltage-gated potassium channel kv 11.1 is the molecular basis for the ikr current, which plays an important role in cardiac physiology. its malfunction is associated with both inherited and acquired cardiac arrhythmias. native currents differ from those in experimental models, suggesting additional regulatory mechanisms. we hypothesized that the post-translational modification sumoylation fine-tunes channel activity.201728888063
interleukin-11 induces and maintains progenitors of different cell lineages during xenopus tadpole tail regeneration.unlike mammals, xenopus laevis tadpoles possess high ability to regenerate their lost organs. in amphibians, the main source of regenerated tissues is lineage-restricted tissue stem cells, but the mechanisms underlying induction, maintenance and differentiation of these stem/progenitor cells in the regenerating organs are poorly understood. we previously reported that interleukin-11 (il-11) is highly expressed in the proliferating cells of regenerating xenopus tadpole tails. here, we show that i ...201728887447
dextmp: deep dive into text for predicting moonlighting proteins.moonlighting proteins (mps) are an important class of proteins that perform more than one independent cellular function. mps are gaining more attention in recent years as they are found to play important roles in various systems including disease developments. mps also have a significant impact in computational function prediction and annotation in databases. currently mps are not labeled as such in biological databases even in cases where multiple distinct functions are known for the proteins. ...201728881966
loss of fourth electron-transferring tryptophan in animal (6-4) photolyase impairs dna repair activity in bacterial cells.(6-4) photolyases [(6-4)pls] are flavoproteins that use blue light to repair the ultraviolet-induced pyrimidine(6-4)pyrimidone photoproduct in dna. their flavin adenine dinucleotide (fad) cofactor can be reduced to its repair-active fadh- form by a photoinduced electron transfer reaction. in animal (6-4)pls, a chain of four trp residues was suggested to be involved in a stepwise transfer of an oxidation hole from the flavin to the surface of the protein. here, we investigated the effect of mutat ...201728880077
methylisothiazolinone toxicity and inhibition of wound healing and regeneration in planaria.methylisothiazolinone (mit) is a common biocide used in cosmetic and industrial settings. studies have demonstrated that mit is a human sensitizer, to the extent that in 2013 mit was named allergen of the year. recently, we showed that mit exposure in xenopus laevis (the african clawed frog) inhibits wound healing and tail regeneration. however, it is unknown whether mit affects these processes in other animals. here, we investigated the effects of mit exposure in planaria-non-parasitic freshwat ...201728869924
in vitro reconstitution of the endoplasmic reticulum.reconstitution of cellular organelles in vitro offers the possibility to perform quantitative and qualitative experiments in a controlled environment that cannot be done with the same accuracy in living cells. following a previous report, the subsequent list of protocols describes how to reconstitute and quantify a tubular er network in vitro based on purified microsomes from culture cells and cytosol from xenopus laevis egg extracts. biological material preparation and reconstitution assays req ...201728862340
advances in the use of xenopus for successful drug screening.understanding embryogenesis currently relies largely on the control of gene expression via several signaling pathways. many of the embryonic signaling pathways guiding embryological events are implicated in diseases that lack effective cure or treatment. because of the large number and size of the eggs, the rapid development of the embryos and the fact they are amenable to pharmacological, surgical and genetic techniques, xenopus laevis has been successfully used in searching for compounds that ...201728846034
dual control of pcdh8l/pcns expression and function in xenopus laevis neural crest cells by adam13/33 via the transcription factors tfap2α and arid3a.adam13/33 is a cell surface metalloprotease critical for cranial neural crest (cnc) cell migration. it can cleave multiple substrates including itself, fibronectin, ephrinb, cadherin-11, pcdh8 and pcdh8l (this work). cleavage of cadherin-11 produces an extracellular fragment that promotes cnc migration. in addition, the adam13 cytoplasmic domain is cleaved by gamma secretase, translocates into the nucleus and regulates multiple genes. here, we show that adam13 interacts with the arid3a/dril1/bri ...201728829038
assembly rules for gabaa receptor complexes in the brain.gabaa receptor (gabaar) pentamers are assembled from a pool of 19 subunits, and variety in subunit combinations diversifies gabaar functions to tune brain activity. pentamers with distinct subunit compositions localize differentially at synaptic and non-synaptic sites to mediate phasic and tonic inhibition, respectively. despite multitudes of theoretical permutations, limited subunit combinations have been identified in the brain. currently, no molecular model exists for combinatorial gabaar ass ...201728816653
the crystal structure of full-length sizzled from xenopus laevis yields insights into wnt-antagonistic function of secreted frizzled-related proteins.the wnt-signaling pathway is crucial to cell proliferation, differentiation, and migration. the secreted frizzled-related proteins (sfrps) represent the largest family of secreted wnt inhibitors. however, their function in antagonizing wnt signaling has remained somewhat controversial. here, we report the crystal structure of sizzled from xenopus laevis, the first full-length structure of an sfrp. tethered by an inter-domain disulfide bond and a linker, the n-terminal cysteine-rich domain (crd) ...201728808056
clathrodin, hymenidin and oroidin, and their synthetic analogues as inhibitors of the voltage-gated potassium channels.we have prepared three alkaloids from the agelas sponges, clathrodin, hymenidin and oroidin, and a series of their synthetic analogues, and evaluated their inhibitory effect against six isoforms of the kv1 subfamily of voltage-gated potassium channels, kv1.1-kv1.6, expressed in chinese hamster ovary (cho) cells using automated patch clamp electrophysiology assay. the most potent inhibitor was the (e)-n-(3-(2-amino-1h-imidazol-4-yl)allyl)-4,5-dichloro-1h-pyrrole-2-carboxamide (6g) with ic50 value ...201728802123
both nuclear size and dna amount contribute to midblastula transition timing in xenopus laevis.during early xenopus laevis embryogenesis both nuclear and cell volumes decrease with the nuclear-to-cytoplasmic (n/c) volume ratio reaching a maximum at the midblastula transition (mbt). at the mbt, embryonic transcription is upregulated and cell cycles lengthen. early studies demonstrated a role for the dna-to-cytoplasmic ratio in the control of mbt timing. by altering nuclear size, we previously showed that the n/c volume ratio also contributes to proper mbt timing. here we examine the relati ...201728801588
role of aqp9 in transport of monomethyselenic acid and selenite.aqp9 is an aquaglyceroporin with a very broad substrate spectrum. in addition to its orthodox nutrient substrates, aqp9 also transports multiple neutral and ionic arsenic species including arsenic trioxide, monomethylarsenous acid (masiii) and dimethylarsenic acid (dmav). here we discovered a new group of aqp9 substrates which includes two clinical relevant selenium species. we showed that aqp9 efficiently transports monomethylselenic acid (msea) with a preference for acidic ph, which has been d ...201728798983
in vivo analysis of the neurovascular niche in the developing xenopus brain.the neurovascular niche is a specialized microenvironment formed by the interactions between neural progenitor cells (npcs) and the vasculature. while it is thought to regulate adult neurogenesis by signaling through vascular-derived soluble cues or contacted-mediated cues, less is known about the neurovascular niche during development. in xenopus laevis tadpole brain, npcs line the ventricle and extend radial processes tipped with endfeet to the vascularized pial surface. using in vivo labeling ...201728795134
comprehensive analyses of hox gene expression in xenopus laevis embryos and adult tissues.from whole genome sequencing of an allotetraploid frog, xenopus laevis, two homeologous sets (l and s) of four hox clusters a through d (hoxa.l/s, hoxb.l/s, hoxc.l/s, and hoxd.l/s) and 13 paralogous groups (pgs) with 76 genes were identified, allowing us to carry out the first comprehensive analyses of hox gene expression in vertebrates. expression of all hox genes during development and in adult tissues was analyzed by rna-sequencing. the expression levels of most hox genes were similar between ...201728791673
the α2β2 isoform combination dominates the astrocytic na+ /k+ -atpase activity and is rendered nonfunctional by the α2.g301r familial hemiplegic migraine type 2-associated mutation.synaptic activity results in transient elevations in extracellular k+ , clearance of which is critical for sustained function of the nervous system. the k+ clearance is, in part, accomplished by the neighboring astrocytes by mechanisms involving the na+ /k+ -atpase. the na+ /k+ -atpase consists of an α and a β subunit, each with several isoforms present in the central nervous system, of which the α2β2 and α2β1 isoform combinations are kinetically geared for astrocytic k+ clearance. while transcr ...201728787093
hmmr mediates anterior neural tube closure and morphogenesis in the frog xenopus.development of the central nervous system requires orchestration of morphogenetic processes which drive elevation and apposition of the neural folds and their fusion into a neural tube. the newly formed tube gives rise to the brain in anterior regions and continues to develop into the spinal cord posteriorly. conspicuous differences between the anterior and posterior neural tube become visible already during neural tube closure (ntc). planar cell polarity (pcp)-mediated convergent extension (ce) ...201728778799
combining cytotoxicity assessment and xenopus laevis phenotypic abnormality assay as a predictor of nanomaterial safety.the african clawed frog, xenopus laevis, has been used as an efficient pre-clinical screening tool to predict drug safety during the early stages of the drug discovery process. x. laevis is a relatively inexpensive model that can be used in whole organism high-throughput assays whilst maintaining a high degree of homology to the higher vertebrate models often used in scientific research. despite an ever-increasing volume of biomedical nanoparticles (nps) in development, their unique physico-chem ...201728777439
tectal corticotropin-releasing factor (crf) neurons respond to fasting and a reactive stressor in the african clawed frog, xenopus laevis.it is well established that hypothalamic neurons producing the peptide corticotropin-releasing factor (crf) play a key role in stress adaptation, including reduction of food intake when a threat or stressor is present. we have previously reported on the presence of an intrinsic crf signaling system within the optic tectum (ot), a brain area that plays a key role in visually guided prey capture/predator avoidance decisions. to better understand the potential role of tectal crf neurons in regulati ...201728774755
the zahn drawings: new illustrations of xenopus embryo and tadpole stages for studies of craniofacial development.the embryos and tadpoles of the frog xenopus are increasingly important subjects for studies of the development of the head and face - studies that are providing novel and crucial insight into the causes and prevention of a suite of devastating birth defects, as well as basic evolutionary and developmental biology. however, many studies are conducted on a range of embryonic stages that are not fully represented in the beloved xenopus resource, nieuwkoop and faber's classic normal table of xenopu ...201728765211
modeling dominant and recessive forms of retinitis pigmentosa by editing three rhodopsin-encoding genes in xenopus laevis using crispr/cas9.the utility of xenopus laevis, a common research subject for developmental biology, retinal physiology, cell biology, and other investigations, has been limited by lack of a robust gene knockout or knock-down technology. here we describe manipulation of the x. laevis genome using crispr/cas9 to model the human disorder retinitis pigmentosa, and to introduce point mutations or exogenous dna sequences. we introduced and characterized in-frame and out-of-frame insertions and deletions in three gene ...201728761125
Refresh
firstprev
...161162163164165166167168169170...
nextlast
Displaying items 16101 - 16200 of 17138