Publications

mutant elovl4 that causes autosomal dominant stargardt-3 macular dystrophy is misrouted to rod outer segment disks.	autosomal dominant stargardt macular dystrophy caused by mutations in the elongation of very long chain fatty acids (elovl4) gene results in macular degeneration, leading to early childhood blindness. transgenic mice and pigs expressing mutant elovl4 develop progressive photoreceptor degeneration. the mechanism by which these mutations cause macular degeneration remains unclear, but have been hypothesized to involve the loss of an er-retention dilysine motif located in the extreme c-terminus. do ...	2014	24833735
mta2 promotes tipin-dependent maintenance of replication fork integrity.	orderly progression of s phase requires the action of replisome-associated tipin and tim1 proteins, whose molecular function is poorly understood. here, we show that tipin deficiency leads to the accumulation of aberrant replication intermediates known as reversed forks. we identified mta2, a subunit of the nurd chromatin remodeler complex, as a novel tipin binding partner and mediator of its function. mta2 is required for tipin-dependent polymerase α binding to replicating chromatin, and this f ...	2014	24830473
transmembrane voltage potential of somatic cells controls oncogene-mediated tumorigenesis at long-range.	the microenvironment is increasingly recognized as a crucial aspect of cancer. in contrast and complement to the field's focus on biochemical factors and extracellular matrix, we characterize a novel aspect of host:tumor interaction - endogenous bioelectric signals among non-excitable somatic cells. extending prior work focused on the bioelectric state of cancer cells themselves, we show for the first time that the resting potentials of distant cells are critical for oncogene-dependent tumorigen ...	2014	24830454
distal expression of sprouty (spry) genes during xenopus laevis limb development and regeneration.	the eukaryotic sprouty (spry) proteins are negative regulators of receptor tyrosine kinase signaling pathways, which in turn provide readout for morphogens such as fibroblast growth factors (fgfs) that are essential for many developmental processes, including limb development. in a transcriptome analysis of early proximo-distal patterning of the xenopus laevis limb bud, spry1a, 2 and 4 were predicted to be expressed predominantly in the distal third. expression of all three in the distal limb in ...	2014	24823862
chibby functions in xenopus ciliary assembly, embryonic development, and the regulation of gene expression.	wnt signaling and ciliogenesis are core features of embryonic development in a range of metazoans. chibby (cby), a basal-body associated protein, regulates β-catenin-mediated wnt signaling in the mouse but not drosophila. here we present an analysis of cby's embryonic expression and morphant phenotypes in xenopus laevis. cby rna is supplied maternally, negatively regulated by snail2 but not twist1, preferentially expressed in the neuroectoderm, and regulates β-catenin-mediated gene expression. r ...	2014	25220153
role for endocytosis of a constitutively active gpcr (gpr185) in releasing vertebrate oocyte meiotic arrest.	vertebrate oocytes are naturally arrested at prophase of meiosis i for sustained periods of time before resuming meiosis in a process called oocyte maturation that prepares the egg for fertilization. members of the constitutively active gpr3/6/12 family of g-protein coupled receptors represent important mediators of meiotic arrest. in the frog oocyte the gpr3/12 homolog gprx (renamed gpr185) has been shown to sustain meiotic arrest by increasing intracellular camp levels through gαsβγ. here we s ...	2014	25220151
activation of sox3 gene by thyroid hormone in the developing adult intestinal stem cell during xenopus metamorphosis.	the maturation of the intestine into the adult form involves the formation of adult stem cells in a thyroid hormone (t3)-dependent process in vertebrates. in mammals, this takes place during postembryonic development, a period around birth when the t3 level peaks. due to the difficulty of manipulating late-stage, uterus-enclosed embryos, very little is known about the development of the adult intestinal stem cells. interestingly, the remodeling of the intestine during the t3-dependent amphibian ...	2014	25211587
thyroid hormone-regulated wnt5a/ror2 signaling is essential for dedifferentiation of larval epithelial cells into adult stem cells in the xenopus laevis intestine.	amphibian intestinal remodeling, where thyroid hormone (t3) induces some larval epithelial cells to become adult stem cells analogous to the mammalian intestinal ones, serves as a unique model for studying how the adult stem cells are formed. to clarify its molecular mechanisms, we here investigated roles of non-canonical wnt signaling in the larval-to-adult intestinal remodeling during xenopus laevis metamorphosis.	2014	25211363
identification of dehydroabietc acid from boswellia thurifera resin as a positive gabaa receptor modulator.	in a two-microelectrode voltage clamp assay with xenopus laevis oocytes, a petroleum ether extract (100 μg/ml) of the resin of boswellia thurifera (burseraceae) potentiated gaba-induced chloride currents (igaba) through receptors of the subtype α₁β₂γ₂s by 319.8% ± 79.8%. with the aid of hplc-based activity profiling, three known terpenoids, dehydroabietic acid (1), incensole (2), and akba (3), were identified in the active fractions of the extract. structure elucidation was achieved by means of ...	2014	25200370
divergent antiviral roles of amphibian (xenopus laevis) macrophages elicited by colony-stimulating factor-1 and interleukin-34.	macrophages are integral to amphibian immunity against rvs, as well as to the infection strategies of these pathogens. although csf-1 was considered to be the principal mediator of macrophage development, the il-34 cytokine, which shares no sequence identity with csf-1, is now believed to contribute to vertebrate monopoiesis. however, the respective roles of csf-1- and il-34-derived macrophages are still poorly understood. to delineate the contribution of these macrophage populations to amphibia ...	2014	25190077
diverse functions of kindlin/fermitin proteins during embryonic development in xenopus laevis.	the kindlin/fermitin family includes three proteins involved in regulating integrin ligand-binding activity and adhesion. loss-of-function mutations in kindlins1 and 3 have been implicated in kindler syndrome and leukocyte adhesion deficiency iii (lad-iii) respectively, whereas kindlin2 null mice are embryonic lethal. post translational regulation of cell-cell and cell-ecm adhesion has long been presumed to be important for morphogenesis, however, few specific examples of activation-dependent ch ...	2014	25173804
electrophysiological characterization of human na⁺/taurocholate cotransporting polypeptide (hntcp) heterologously expressed in xenopus laevis oocytes.	the na(+)/taurocholate cotransporting polypeptide (ntcp) plays a major role in na(+)-dependent bile acid uptake into hepatocytes. the purpose of the present study was to establish the heterologous expression of human ntcp (hntcp) in xenopus laevis oocytes and to elucidate whether the transport of bile acid via hntcp is electrogenic using electrophysiological techniques. first, we evaluated the uptake of taurocholate (tca) by hntcp heterologously expressed in xenopus oocytes utilizing [(3)h]-labe ...	2014	25168282
a cycloartane glycoside derived from actaea racemosa l. modulates gabaa receptors and induces pronounced sedation in mice.	23-o-acetylshengmanol 3-o-β-d-xylopyranoside (ac-sm) isolated from actaea racemosa l.-an herbal remedy for the treatment of mild menopausal disorders-has been recently identified as a novel efficacious modulator of gabaa receptors composed of α1-, β2-, and γ2s-subunits. in the present study, we analyzed a potential subunit-selective modulation of gaba-induced chloride currents (igaba) at gaba concentrations eliciting 3-8% of the maximal gaba response (ec3-8) through nine gabaa receptor isoforms ...	2014	25161170
transport of boron by the tassel-less1 aquaporin is critical for vegetative and reproductive development in maize.	the element boron (b) is an essential plant micronutrient, and b deficiency results in significant crop losses worldwide. the maize (zea mays) tassel-less1 (tls1) mutant has defects in vegetative and inflorescence development, comparable to the effects of b deficiency. positional cloning revealed that tls1 encodes a protein in the aquaporin family co-orthologous to known b channel proteins in other species. transport assays show that the tls1 protein facilitates the movement of b and water into ...	2014	25035406
ion selectivity of pore-forming peptides and ion channels measured in xenopus oocytes.	the xenopus laevis oocyte is a widely used system for heterologous expression of exogenous ion channel proteins. they are easy to obtain, mechanically and electrically stable, have a large size, enabling multiple types of electrophysiological recordings: two-electrode voltage clamp, single cell-attached or cell-free patch-clamp and macropatch recordings. the size of an oocyte (1 mm in diameter) also allows for the use of additional electrodes (from 1 to 3) for injection of diverse materials (ca( ...	2014	25023320
berberine attenuates spontaneous action potentials in sinoatrial node cells and the currents of human hcn4 channels expressed in xenopus laevis oocytes.	the present study investigated the electropharmacological effects of a traditional chinese herbal drug, berberine, on the spontaneous activity of sinoatrial nodes (sans) of the rabbit heart and on human hyperpolarization-activated cyclic nucleotide-gated 4 (hhcn4) channels, which are heterologously expressed in xenopus oocytes, and which contribute to pacemaker currents (ifs). a standard microelectrode technique and standard two‑electrode voltage‑clamp recordings were employed to examine the pro ...	2014	25017321
hargreaves does not evaluate nociception following a surgical laparotomy in xenopus leavis frogs.	the present study was performed to determine the effectiveness of the hargreaves test for the evaluation of nociception in frogs, more precisely to determine if cutaneous thresholds to a radiant heat stimulus would increase with analgesics following an abdominal laparotomy performed under general anaesthesia. non breeding female xenopus leavis frogs (3 groups (non-anaesthetized, anaesthetized with tricaine methanesulfonate (ms222), with or without an abdominal laparotomy) were used to evaluate t ...	2014	25016568
nmda receptor structures reveal subunit arrangement and pore architecture.	n-methyl-d-aspartate (nmda) receptors are hebbian-like coincidence detectors, requiring binding of glycine and glutamate in combination with the relief of voltage-dependent magnesium block to open an ion conductive pore across the membrane bilayer. despite the importance of the nmda receptor in the development and function of the brain, a molecular structure of an intact receptor has remained elusive. here we present x-ray crystal structures of the xenopus laevis glun1-glun2b nmda receptor with ...	2014	25008524
transit amplification in the amniote cerebellum evolved via a heterochronic shift in neurod1 expression.	the cerebellum has evolved elaborate foliation in the amniote lineage as a consequence of extensive atoh1-mediated transit amplification in an external germinal layer (egl) comprising granule cell precursors. to explore the evolutionary origin of this layer, we have examined the molecular geography of cerebellar development throughout the life cycle of xenopus laevis. at metamorphic stages xenopus displays a superficial granule cell layer that is not proliferative and expresses both atoh1 and ne ...	2014	25005474
the thymus and skin wound healing in xenopus laevis adults.	the capacity to heal wounds without scars is generally lost during the development in vertebrates. to explore the involvement of cells of the adaptive immune system in a scar-like tissue based repair, we studied the thymus in 15-month-old xenopus after skin incisional wounding. after injury, the organ size significantly increased and marked changes in structure and tnf-α immunoreactivity were detected in the medullary microenvironment when the granulation tissue was present in the repair area. m ...	2014	24998030
revealing transient structures of nucleosomes as dna unwinds.	the modulation of dna accessibility by nucleosomes is a fundamental mechanism of gene regulation in eukaryotes. the nucleosome core particle (ncp) consists of 147 bp of dna wrapped around a symmetric octamer of histone proteins. the dynamics of dna packaging and unpackaging from the ncp affect all dna-based chemistries, but depend on many factors, including dna positioning sequence, histone variants and modifications. although the structure of the intact ncp has been studied by crystallography a ...	2014	24990379
conformational flexibility of the agonist binding jaw of the human p2x3 receptor is a prerequisite for channel opening.	it is assumed that atp induces closure of the binding jaw of ligand-gated p2x receptors, which eventually results in the opening of the membrane channel and the flux of cations. immobilization by cysteine mutagenesis of the binding jaw inhibited atp-induced current responses, but did not allow discrimination between disturbances of binding, gating, subunit assembly or trafficking to the plasma membrane.	2014	24989924
efficacy of tricaine methanesulfonate (ms-222) as an anesthetic agent for blocking sensory-motor responses in xenopus laevis tadpoles.	anesthetics are drugs that reversibly relieve pain, decrease body movements and suppress neuronal activity. most drugs only cover one of these effects; for instance, analgesics relieve pain but fail to block primary fiber responses to noxious stimuli. alternately, paralytic drugs block synaptic transmission at neuromuscular junctions, thereby effectively paralyzing skeletal muscles. thus, both analgesics and paralytics each accomplish one effect, but fail to singularly account for all three. tri ...	2014	24984086
positive allosteric modulation of the ghb high-affinity binding site by the gabaa receptor modulator monastrol and the flavonoid catechin.	γ-hydroxybutyric acid (ghb) is a metabolite of γ-aminobutyric acid (gaba) and a proposed neurotransmitter in the mammalian brain. we recently identified α4βδ gabaa receptors as possible high-affinity ghb targets. gabaa receptors are highly sensitive to allosteric modulation. thus to investigate whether ghb high-affinity binding sites are also sensitive to allosteric modulation, we screened both known gabaa receptor ligands and a library of natural compounds in the rat cortical membrane ghb speci ...	2014	24973695
identification and lateral membrane localization of cyclin m3, likely to be involved in renal mg2+ handling in seawater fish.	the kidney of marine teleosts is the major site of mg(2+) excretion and produces urine with a high mg(2+) concentration. however, the transporters involved in mg(2+) excretion are poorly understood. the cyclin m (cnnm; also known as ancient conserved domain protein) family comprises membrane proteins homologous to the bacterial mg(2+) and co(2+) efflux protein, corc. to understand the molecular mechanism of mg(2+) homeostasis in marine teleosts, we analyzed the expression of the cnnm family gene ...	2014	24965791
tetrabromobisphenol a disrupts vertebrate development via thyroid hormone signaling pathway in a developmental stage-dependent manner.	data concerning effects of tetrabromobisphenol a (tbbpa) on thyroid hormone (th)-dependent vertebrate development have been limited, although tbbpa has been demonstrated in vitro to disrupt the th signaling pathway at the transcriptional level. in this study, we investigated the effects of tbbpa on t3-induced and spontaneous xenopus laevis metamorphosis, which share many similarities with th-dependent development in higher vertebrates. in a 6-day t3-induced metamorphosis assay using premetamorph ...	2014	24963557
changes of statistical structural fluctuations unveils an early compacted degraded stage of pns myelin.	degradation of the myelin sheath is a common pathology underlying demyelinating neurological diseases from multiple sclerosis to leukodistrophies. although large malformations of myelin ultrastructure in the advanced stages of wallerian degradation is known, its subtle structural variations at early stages of demyelination remains poorly characterized. this is partly due to the lack of suitable and non-invasive experimental probes possessing sufficient resolution to detect the degradation. here ...	2014	24962806
a simple behavioral assay for testing visual function in xenopus laevis.	measurement of the visual function in the tadpoles of the frog, xenopus laevis, allows screening for blindness in live animals. the optokinetic response is a vision-based, reflexive behavior that has been observed in all vertebrates tested. tadpole eyes are small so the tail flip response was used as alternative measure, which requires a trained technician to record the subtle response. we developed an alternative behavior assay based on the fact that tadpoles prefer to swim on the white side of ...	2014	24962702
reconstitution of β-catenin degradation in xenopus egg extract.	xenopus laevis egg extract is a well-characterized, robust system for studying the biochemistry of diverse cellular processes. xenopus egg extract has been used to study protein turnover in many cellular contexts, including the cell cycle and signal transduction pathways(1-3). herein, a method is described for isolating xenopus egg extract that has been optimized to promote the degradation of the critical wnt pathway component, β-catenin. two different methods are described to assess β-catenin p ...	2014	24962160
actions of hydrogen sulfide on sodium transport processes across native distal lung epithelia (xenopus laevis).	hydrogen sulfide (h2s) is well known as a highly toxic environmental chemical threat. prolonged exposure to h2s can lead to the formation of pulmonary edema. however, the mechanisms of how h2s facilitates edema formation are poorly understood. since edema formation can be enhanced by an impaired clearance of electrolytes and, consequently, fluid across the alveolar epithelium, it was questioned whether h2s may interfere with transepithelial electrolyte absorption. electrolyte absorption was elec ...	2014	24960042
deep proteomics of the xenopus laevis egg using an mrna-derived reference database.	mass spectrometry-based proteomics enables the global identification and quantification of proteins and their posttranslational modifications in complex biological samples. however, proteomic analysis requires a complete and accurate reference set of proteins and is therefore largely restricted to model organisms with sequenced genomes.	2014	24954049
annotation of loci from genome-wide association studies using tissue-specific quantitative interaction proteomics.	genome-wide association studies (gwas) have identified thousands of loci associated with complex traits, but it is challenging to pinpoint causal genes in these loci and to exploit subtle association signals. we used tissue-specific quantitative interaction proteomics to map a network of five genes involved in the mendelian disorder long qt syndrome (lqts). we integrated the lqts network with gwas loci from the corresponding common complex trait, qt-interval variation, to identify candidate gene ...	2014	24952909
nucleosomal regulation of chromatin composition and nuclear assembly revealed by histone depletion.	nucleosomes are the fundamental unit of chromatin, but analysis of transcription-independent nucleosome functions has been complicated by the gene-expression changes resulting from histone manipulation. here we solve this dilemma by developing xenopus laevis egg extracts deficient for nucleosome formation and by analyzing the proteomic landscape and behavior of nucleosomal chromatin and nucleosome-free dna. we show that although nucleosome-free dna can recruit nuclear-envelope membranes, nucleos ...	2014	24952593
motion based x-ray imaging modality.	a new x-ray imaging method (patent pending) was developed to visualize function-related motion information. we modify existing x-ray imaging methods to provide four images without increasing the necessary measurement time or radiation dose. the most important of these images is a new "kinetic" image that represents motions inside the object or living body. the motion-based contrast of the kinetic image can help visualize details that were not accessible before. the broad range of the movements a ...	2014	24951684
the transport mechanism of the human sodium/myo-inositol transporter 2 (smit2/sglt6), a member of the leut structural family.	the sodium/myo-inositol transporter 2 (smit2) is a member of the slc5a gene family, which is believed to share the five-transmembrane segment inverted repeat of the leut structural family. the two-electrode voltage-clamp (tevc) technique was used to measure the steady-state and the pre-steady-state currents mediated by human smit2 after expression in xenopus laevis oocytes. phlorizin is first shown to be a poor inhibitor of pre-steady-state currents for depolarizing voltage pulse. from an up to ...	2014	24944204
diuresis by intravenous administration of xanthurenic acid in rats, and inhibition by probenecid.	the conjugates with sulfate and glucoside of xanthurenic acid, a tryptophan metabolite, were reported to show natriuresis. sulfotransferase for xanthurenic acid works in the renal proximal tubule to produce the sulfate of xanthurenic acid as well as the liver, and we recently found that xanthurenic acid is a substrate of renal organic anion transporter oat1. the purpose of this study was to examine relationship between the transport by oat1 and diuresis related with xanthurenic acid. drug transp ...	2014	24942862
functional analysis of human na(+)/k(+)-atpase familial or sporadic hemiplegic migraine mutations expressed in xenopus oocytes.	functional characterization of atp1a2 mutations that are related to familial or sporadic hemiplegic migraine (fhm2, shm).	2014	24921013
wnk3 abrogates the nedd4-2-mediated inhibition of the renal na+-cl- cotransporter.	the serine/threonine kinase wnk3 and the ubiquitin-protein ligase nedd4-2 are key regulators of the thiazide-sensitive na+-cl- cotransporter (ncc), wnk3 as an activator and nedd2-4 as an inhibitor. nedd4-2 was identified as an interacting partner of wnk3 through a glutathione-s-transferase pull-down assay using the n-terminal domain of wnk3, combined with lc-ms/ms analysis. this was validated by coimmunoprecipitation of wnk3 and nedd4-2 expressed in hek293 cells. our data also revealed that the ...	2014	24920754
submembrane assembly and renewal of rod photoreceptor cgmp-gated channel: insight into the actin-dependent process of outer segment morphogenesis.	the photoreceptor outer segment (os) is comprised of two compartments: plasma membrane (pm) and disk membranes. it is unknown how the pm renewal is coordinated with that of the disk membranes. here we visualized the localization and trafficking process of rod cyclic nucleotide-gated channel α-subunit (cnga1), a pm component essential for phototransduction. the localization was visualized by fusing cnga1 to a fluorescent protein dendra2 and expressing in xenopus laevis rod photoreceptors. dendra2 ...	2014	24920621
generation of endo-sirnas in xenopus laevis oocytes.	endogenous sirnas (endo-sirnas) are well documented and characterized in c. elegans and drosophila. endo-sirnas can also be found in vertebrates; however, their biology is much less clear. they are thought to be produced by dicer and to contribute to transposon silencing. because of their generally low abundance and their similarity with mirnas and products of physiological rna turn-over, endo-sirnas are difficult to investigate. here, we report a system, oocytes from xenopus laevis, that allows ...	2014	24920357
phoretic interaction between the kangaroo leech marsupiobdella africana (hirudinea: glossiphoniidae) and the cape river crab potamonautes perlatus (decapoda: potamonautidae).	the south african leech marsupiobdella africana is a temporary ectoparasite of the amphibian xenopus laevis, has a phoretic association with a freshwater crab potamonautes perlatus, and exhibits advanced parental care by incubating its offspring in a brood pouch. because phoretic associations are usually regarded to favor the phoront's dispersion, its occurrence within the biology of a parasitic species reflects an intimate context of interactions. in addition to phoresy, attachment to the crab ...	2014	24918071
ncoa4 transcriptional coactivator inhibits activation of dna replication origins.	ncoa4 is a transcriptional coactivator of nuclear hormone receptors that undergoes gene rearrangement in human cancer. by combining studies in xenopus laevis egg extracts and mouse embryonic fibroblasts (mefs), we show here that ncoa4 is a minichromosome maintenance 7 (mcm7)-interacting protein that is able to control dna replication. depletion-reconstitution experiments in xenopus laevis egg extracts indicate that ncoa4 acts as an inhibitor of dna replication origin activation by regulating cmg ...	2014	24910095
endothelin modulates the circadian expression of non-visual opsins.	the non-visual opsin, melanopsin, expressed in the mammalian retina, is considered a circadian photopigment because it is responsible to entrain the endogenous biological clock. this photopigment is also present in the melanophores of xenopus laevis, where it was first described, but its role in these cells is not fully understood. x. laevis melanophores respond to light with melanin granule dispersion, the maximal response being achieved at the wavelength of melanopsin maximal excitation. pigme ...	2014	24816266
single cell wound generates electric current circuit and cell membrane potential variations that requires calcium influx.	breaching of the cell membrane is one of the earliest and most common causes of cell injury, tissue damage, and disease. if the compromise in cell membrane is not repaired quickly, irreversible cell damage, cell death and defective organ functions will result. it is therefore fundamentally important to efficiently repair damage to the cell membrane. while the molecular aspects of single cell wound healing are starting to be deciphered, its bio-physical counterpart has been poorly investigated. u ...	2014	24801267
caging, but not air deprivation, slows tadpole growth and development in the amphibian xenopus laevis.	xenopus laevis tadpoles raised in submerged cages in normoxic water develop more slowly than tadpoles raised with access to air. this study distinguishes between the effects of being caged and being deprived access to air on development and growth. tadpoles were raised in high and low density control tanks and in cages in the same tank that were either completely submerged or with the top exposed to air. experiments were repeated with the cages in different positions relative to the air stones a ...	2014	24799365
maternal syntabulin is required for dorsal axis formation and is a germ plasm component in xenopus.	in amphibians and teleosts, early embryonic axial development is driven by maternally deposited mrnas and proteins, called dorsal determinants, which migrate to the presumptive dorsal side of the embryo in a microtubule-dependent manner after fertilization. syntabulin is an adapter protein that binds to kinesin kif5b and to the transmembrane protein syntaxin1. in zebrafish, a mutation in syntabulin causes complete embryo ventralization. it is unknown whether syntabulin plays an analogous role du ...	2014	24798204
structural and functional similarity of amphibian constitutive androstane receptor with mammalian pregnane x receptor.	the nuclear receptors and xenosensors constitutive androstane receptor (car, nr1i3) and pregnane x receptor (pxr, nr1i2) induce the expression of xenobiotic metabolizing enzymes and transporters, which also affects various endobiotics. while human and mouse car feature a high basal activity and low induction upon ligand exposure, we recently identified two constitutive androstane receptors in xenopus laevis (xlcará and â) that possess pxr-like characteristics such as low basal activity and activ ...	2014	24797902
thyroid hormones in the skeletogenesis and accessory sources of endogenous hormones in xenopus laevis (amphibia; anura) ontogeny: experimental evidence.	skeletal development was studied in normal and goitrogen-treated xenopus laevis tadpoles reared under thyroid hormone (th) deficiency. early stages of skeletal development proceed similarly in both groups. later stages are retarded or completely arrested in goitrogen-treated tadpoles. after goitrogen-treated tadpoles were transferred into pure water or into a medium containing both goitrogen and exogenous th, tadpoles resumed development. consequently, late stages of skeletogenesis are th-depend ...	2014	24795191
investigating physical chromatin associations across the xenopus genome by chromatin immunoprecipitation.	chromatin immunoprecipitation (chip) combined with genomic analysis techniques provide a global snapshot of protein-dna interactions in the context of chromatin, yielding insights into which genomic loci might be regulated by the dna-associated protein under investigation. this protocol describes how to perform chip on intact or dissected xenopus embryos. the chip-isolated dna fragments are suitable for high-throughput sequencing (chip-seq) or for quantitative pcr (chip-qpcr). in this protocol, ...	2014	24786504
african clawed toads (xenopus laevis) sense the distance of lateral line stimuli.	sighted african clawed toads use their lateral lines to detect stimulus distance, although accuracy and precision are poorer than for stimulus direction. single surface wave trains elicited discrete turns and/or swims towards the wave origin. most responses were brief, ending with the toad stationary (70% overall; 54-86% individual toads) or pausing before turning away (11%; 1-24%). lunges or capturing movements with the arms (13%; 10-22%) also indicated where toads expected to find prey. overal ...	2014	24781249
nucleoside transporters and human organic cation transporter 1 determine the cellular handling of dna-methyltransferase inhibitors.	inhibitors of dna methyltransferases (dnmts), such as azacytidine, decitabine and zebularine, are used for the epigenetic treatment of cancer. their action may depend upon their translocation across the plasma membrane. the aim of this study was to identify transporter proteins contributing to dnmt inhibitor action.	2014	24780098
biomechanics and the thermotolerance of development.	successful completion of development requires coordination of patterning events with morphogenetic movements. environmental variability challenges this coordination. for example, developing organisms encounter varying environmental temperatures that can strongly influence developmental rates. we hypothesized that the mechanics of morphogenesis would have to be finely adjusted to allow for normal morphogenesis across a wide range of developmental rates. we formulated our hypothesis as a simple mo ...	2014	24776615
unusual evolutionary conservation and further species-specific adaptations of a large family of nonclassical mhc class ib genes across different degrees of genome ploidy in the amphibian subfamily xenopodinae.	nonclassical mhc class ib (class ib) genes are a family of highly diverse and rapidly evolving genes wherein gene numbers, organization, and expression markedly differ even among closely related species rendering class ib phylogeny difficult to establish. whereas among mammals there are few unambiguous class ib gene orthologs, different amphibian species belonging to the anuran subfamily xenopodinae exhibit an unusually high degree of conservation among multiple class ib gene lineages. comparati ...	2014	24771209
the wnt/jnk signaling target gene alcam is required for embryonic kidney development.	proper development of nephrons is essential for kidney function. β-catenin-independent wnt signaling through fzd8, inversin, daam1, rhoa and myosin is required for nephric tubule morphogenesis. here, we provide a novel mechanism through which non-canonical wnt signaling contributes to tubular development. using xenopus laevis as a model system, we found that the cell-adhesion molecule alcam is required for proper nephrogenesis and functions downstream of fzd3 during embryonic kidney development. ...	2014	24764076
monoterpene glycoside esk246 from pittosporum targets lat3 amino acid transport and prostate cancer cell growth.	the l-type amino acid transporter (lat) family consists of four members (lat1-4) that mediate uptake of neutral amino acids including leucine. leucine is not only important as a building block for proteins, but plays a critical role in mtorc1 signaling leading to protein translation. as such, lat family members are commonly upregulated in cancer in order to fuel increased protein translation and cell growth. to identify potential lat-specific inhibitors, we established a function-based high-thro ...	2014	24762008
a device for emulating cuff recordings of action potentials propagating along peripheral nerves.	this paper describes a device that emulates propagation of action potentials along a peripheral nerve, suitable for reproducible testing of bio-potential recording systems using nerve cuff electrodes. the system is a microcontroller-based stand-alone instrument which uses established nerve and electrode models to represent neural activity of real nerves recorded with a nerve cuff interface, taking into consideration electrode impedance, voltages picked up by the electrodes, and action potential ...	2014	24760928
11-trifluoromethyl-phenyldiazirinyl neurosteroid analogues: potent general anesthetics and photolabeling reagents for gabaa receptors.	while neurosteroids are well-described positive allosteric modulators of gamma-aminobutyric acid type a (gabaa) receptors, the binding sites that mediate these actions have not been definitively identified.	2014	24756762
facial transplants in xenopus laevis embryos.	craniofacial birth defects occur in 1 out of every 700 live births, but etiology is rarely known due to limited understanding of craniofacial development. to identify where signaling pathways and tissues act during patterning of the developing face, a 'face transplant' technique has been developed in embryos of the frog xenopus laevis. a region of presumptive facial tissue (the "extreme anterior domain" (ead)) is removed from a donor embryo at tailbud stage, and transplanted to a host embryo of ...	2014	24748020
trpc2 is expressed in two olfactory subsystems, the main and the vomeronasal system of larval xenopus laevis.	complete segregation of the main olfactory epithelium (moe) and the vomeronasal epithelium is first observed in amphibians. in contrast, teleost fishes possess a single olfactory surface, in which genetic components of the main and vomeronasal olfactory systems are intermingled. the transient receptor potential channel trpc2, a marker of vomeronasal neurons, is present in the single fish sensory surface, but is already restricted to the vomeronasal epithelium in a terrestrial amphibian, the red- ...	2014	24737764
chd7, the gene mutated in charge syndrome, regulates genes involved in neural crest cell guidance.	heterozygous loss of function mutations in chd7 (chromodomain helicase dna-binding protein 7) lead to charge syndrome, a complex developmental disorder affecting craniofacial structures, cranial nerves and several organ systems. recently, it was demonstrated that chd7 is essential for the formation of multipotent migratory neural crest cells, which migrate from the neural tube to many regions of the embryo, where they differentiate into various tissues including craniofacial and heart structures ...	2014	24728844
prolonged in vivo imaging of xenopus laevis.	while live imaging of embryonic development over long periods of time is a well established method for embryos of the frog xenopus laevis, once development has progressed to the swimming stages, continuous live imaging becomes more challenging because the tadpoles must be immobilized. current imaging techniques for these advanced stages generally require bringing the tadpoles in and out of anesthesia for short imaging sessions at selected time points, severely limiting the resolution of the data ...	2014	24723337
functional analysis of a missense mutation in the serine protease inhibitor spint2 associated with congenital sodium diarrhea.	membrane-bound serine proteases play important roles in different biological processes. their regulation by endogenous inhibitors is poorly understood. a y163c mutation in the spint2 gene encoding the serine protease inhibitor hepatocyte growth factor inhibitor hai-2 is associated with a congenital sodium diarrhea. the functional consequences of this mutation on hai-2 activity and its physiological targets are unknown. we established a cellular assay in xenopus laevis oocytes to study functional ...	2014	24722141
immunohistochemical analysis of pax6 and pax7 expression in the cns of adult xenopus laevis.	pax6 and pax7 are transcription factors essential for the development of the cns. in addition, increasing data, mainly obtained in amniotes, support that they are expressed in subsets of neurons in the adult, likely playing a role in maintaining neuron type identity. in the present study we analyzed the detailed distribution of pax6 and pax7 cells in the adult cns of xenopus laevis. immunohistochemistry with antibodies that are required for high-resolution analysis of pax-expressing cells was co ...	2014	24717807
the egg membrane microdomain-associated uroplakin iii-src system becomes functional during oocyte maturation and is required for bidirectional gamete signaling at fertilization in xenopus laevis.	in xenopus laevis, sperm-egg interaction promotes partial proteolysis and/or tyrosine phosphorylation of uroplakin iii (upiii) and the tyrosine kinase src, which both localize to the cholesterol-enriched egg membrane microdomains (mds). here we show that sperm promote proteolysis and/or tyrosine phosphorylation of upiii and src in mds isolated from ovulated and unfertilized eggs (uf-mds). an antibody against the extracellular domain of upiii interferes with these events. inhibition of fertilizat ...	2014	24715460
differential modulation of gaba(a) receptor function by aryl pyrazoles.	several aryl pyrazoles characterized by a different molecular structure (flexible vs constrained), but chemically related to rimonabant and am251, were tested for their ability to modulate the function of recombinant α1β2γ2l gabaa receptors expressed in xenopus laevis oocytes. the effects of 6bio-r, 14bio-r, ness 0327, gp1a and gp2a (0.3-30 μm) were evaluated using a two-electrode voltage-clamp technique. 6bio-r and 14bio-r potentiated gaba-evoked cl(-) currents. ness 0327, gp1a and gp2a did not ...	2014	24704372
behavioral observation of xenopus tadpole swimming for neuroscience labs.	neuroscience labs benefit from reliable, easily-monitored neural responses mediated by well-studied neural pathways. xenopus laevis tadpoles have been used as a simple vertebrate model preparation in motor control studies. most of the neuronal pathways underlying different aspects of tadpole swimming behavior have been revealed. these include the skin mechanosensory touch and pineal eye light-sensing pathways whose activation can initiate swimming, and the cement gland pressure-sensing pathway r ...	2014	24693257
marine natural products acting on the acetylcholine-binding protein and nicotinic receptors: from computer modeling to binding studies and electrophysiology.	for a small library of natural products from marine sponges and ascidians, in silico docking to the lymnaea stagnalis acetylcholine-binding protein (achbp), a model for the ligand-binding domains of nicotinic acetylcholine receptors (nachrs), was carried out and the possibility of complex formation was revealed. it was further experimentally confirmed via competition with radioiodinated α-bungarotoxin ([¹²⁵i]-αbgt) for binding to achbp of the majority of analyzed compounds. alkaloids pibocin, va ...	2014	24686559
ire1α is essential for xenopus pancreas development.	inositol requiring enzyme-1 (ire1) is highly conserved from yeasts to humans. upon the endoplasmic reticulum (er) stress, ire1 activates x-box-binding protein 1 (xbp1) by unconventionally splicing xbp1 mrna, which activates the unfolded protein response (upr) to restore er homeostasis. in mice, ire1α inactivity leads to embryonic death and ire1α plays an essential role in extraembryonic tissues and the placenta. however, its precise action in the embryo proper is still unknown. in this study, th ...	2014	24683410
ephrinb2 affects apical constriction in xenopus embryos and is regulated by adam10 and flotillin-1.	the eph/ephrin signalling pathways have a critical function in cell adhesion and repulsion, and thus play key roles in various morphogenetic events during development. here we show that a decrease in ephrinb2 protein causes neural tube closure defects during xenopus laevis embryogenesis. such a decrease in ephrinb2 protein levels is observed on the loss of flotillin-1 scaffold protein, a newly identified ephrinb2-binding partner. this dramatic decline in ephrinb2 protein levels on the absence of ...	2014	24662724
purification and characterization of a urea sensitive lactate dehydrogenase from the liver of the african clawed frog, xenopus laevis.	the african clawed frog, xenopus laevis, is able to withstand extremely arid conditions by estivating, in conjunction with dehydration tolerance and urea accumulation. estivating x. laevis reduce their metabolic rate and recruit anaerobic glycolysis, driven by lactate dehydrogenase (ldh; e.c. 1.1.1.27) enzymes that reversibly convert pyruvate and nadh to lactate and nad(+), to meet newly established atp demands. the present study investigated purified ldh from the liver of dehydrated and control ...	2014	24651940
disk-shaped amperometric enzymatic biosensor for in vivo detection of d-serine.	at the synapse, d-serine is an endogenous co-agonist for the n-methyl-d-aspartate receptor (nmdar). it plays an important role in synaptic transmission and plasticity and has also been linked to several pathological diseases such as schizophrenia and huntington's. the quantification of local changes in d-serine concentration is essential to further understanding these processes. we report herein the development of a disk-shaped amperometric enzymatic biosensor for detection of d-serine based on ...	2014	24650010
discovery of a potent and selective α3β4 nicotinic acetylcholine receptor antagonist from an α-conotoxin synthetic combinatorial library.	α-conotoxins are disulfide-rich peptide neurotoxins that selectively inhibit neuronal nicotinic acetylcholine receptors (nachrs). the α3β4 nachr subtype has been identified as a novel target for managing nicotine addiction. using a mixture-based positional-scanning synthetic combinatorial library (ps-scl) with the α4/4-conotoxin buia framework, we discovered a highly potent and selective α3β4 nachr antagonist. the initial ps-scl consisted of a total of 113 379 904 sequences that were screened fo ...	2014	24649848
musashi protein-directed translational activation of target mrnas is mediated by the poly(a) polymerase, germ line development defective-2.	the mrna-binding protein, musashi, has been shown to regulate translation of select mrnas and to control cellular identity in both stem cells and cancer cells. within the mammalian cells, musashi has traditionally been characterized as a repressor of translation. however, we have demonstrated that musashi is an activator of translation in progesterone-stimulated oocytes of the frog xenopus laevis, and recent evidence has revealed musashi's capability to function as an activator of translation in ...	2014	24644291
dissection of xenopus laevis neural crest for in vitro explant culture or in vivo transplantation.	the neural crest (nc) is a transient dorsal neural tube cell population that undergoes an epithelium-to-mesenchyme transition (emt) at the end of neurulation, migrates extensively towards various organs, and differentiates into many types of derivatives (neurons, glia, cartilage and bone, pigmented and endocrine cells). in this protocol, we describe how to dissect the premigratory cranial nc from xenopus laevis embryos, in order to study nc development in vivo and in vitro. the frog model offers ...	2014	24637938
the different effects on cranial and trunk neural crest cell behaviour following exposure to a low concentration of alcohol in vitro.	embryonic neural crest cells give rise to large regions of the face and peripheral nervous system. exposure of these cells to high alcohol concentrations leads to cell death in the craniofacial region resulting in facial defects. however, the effects of low concentrations of alcohol on neural crest cells are not clear. in this study, cranial neural crest cells from xenopus laevis were cultured in an ethanol concentration approximately equivalent to one drink. techniques were developed to study v ...	2014	24631632
glycogen-supplemented mitotic cytosol for analyzing xenopus egg microtubule organization.	undiluted cytoplasmic extract prepared from unfertilized xenopus laevis eggs by low-speed centrifugation (csf extracts) is useful for reconstitution of egg microtubule dynamics and meiosis-ii spindle organization, but it suffers limitations for biochemical analysis due to abundant particulates. here, we describe preparation and the use of fully clarified, undiluted mitotic cytosol derived from csf extract. addition of glycogen improves the ability of this cytosol to reconstitute microtubule orga ...	2014	24630120
specificity of calcium/calmodulin-dependent protein kinases in mouse egg activation.	camkiiγ, the predominant camkii isoform in mouse eggs, controls egg activation by regulating cell cycle resumption. in this study we further characterize the involvement and specificity of camkiiγ in mouse egg activation. using exogenous expression of different crnas in camk2g(-/-) eggs, we show that the other multifunctional cam kinases, camki, and camkiv, are not capable of substituting camkiiγ to initiate cell cycle resumption in response to a rise in intracellular ca (2+). exogenous expressi ...	2014	24626179
quantitative proteomics of xenopus laevis embryos: expression kinetics of nearly 4000 proteins during early development.	while there is a rich literature on transcription dynamics during the development of many organisms, protein data is limited. we used itraq isotopic labeling and mass spectrometry to generate the largest developmental proteomic dataset for any animal. expression dynamics of nearly 4,000 proteins of xenopus laevis was generated from fertilized egg to neurula embryo. expression clusters into groups. the cluster profiles accurately reflect the major events that mark changes in gene expression patte ...	2014	24626130
the cost of muscle power production: muscle oxygen consumption per unit work increases at low temperatures in xenopus laevis.	metabolic energy (atp) supply to muscle is essential to support activity and behaviour. it is expected, therefore, that there is strong selection to maximise muscle power output for a given rate of atp use. however, the viscosity and stiffness of muscle increases with a decrease in temperature, which means that more atp may be required to achieve a given work output. here, we tested the hypothesis that atp use increases at lower temperatures for a given power output in xenopus laevis. to account ...	2014	24625645
functional characterization of tissue inhibitor of metalloproteinase-1 (timp-1) n- and c-terminal domains during xenopus laevis development.	extracellular matrix (ecm) remodeling is essential for facilitating developmental processes. ecm remodeling, accomplished by matrix metalloproteinases (mmps), is regulated by endogenous tissue inhibitors of metalloproteinases (timps). while the timp n-terminal domain is involved in inhibition of mmp activity, the c-terminal domain exhibits cell-signaling activity, which is timp and cell type dependent. we have previously examined the distinct roles of the xenopus laevis timp-2 and -3 c-terminal ...	2014	24616631
cyp19a1 (aromatase) expression in the xenopus brain at different developmental stages.	cytochrome p450 aromatase (p450arom; aromatase) is a microsomal enzyme involved in the production of endogeneous sex steroids by converting testosterone into oestradiol. aromatase is the product of the cyp19a1 gene and plays a crucial role in the sexual differentiation of the brain and in the regulation of reproductive functions. in the brain of mammals and birds, expression of cyp19a1 has been demonstrated in neuronal populations of the telencephalon and diencephalon. by contrast, a wealth of e ...	2014	24612124
tail structure is formed when blastocoel roof contacts blastocoel floor in xenopus laevis.	the tail organizer has been assessed by such transplantation methods as the einsteck procedure. however, we found that simple wounding of blastocoel roof (bcr) made it possible to form secondary tails without any transplantation in xenopus laevis. we revealed that the ectopic expression of xbra was blocked by inhibiting the contact between bcr and blastocoel floor (bcf), and wounding per se seemed to be not directly related to the secondary tail formation. therefore, the secondary tail might be ...	2014	24611759
structure of aurora b-incenp in complex with barasertib reveals a potential transinhibitory mechanism.	the aurora family is a well conserved and well characterized group of serine-threonine kinases involved in the normal progression of mitosis. the deregulation of aurora kinases impairs spindle assembly, checkpoint function and cell division. to date, many small molecules that compete with atp for binding to aurora kinases have been developed and characterized. here, the first structure of the xenopus laevis aurora b-incenp complex bound to the clinically relevant small molecule barasertib was de ...	2014	24598913
a novel serotonin-secreting cell type regulates ciliary motility in the mucociliary epidermis of xenopus tadpoles.	the embryonic skin of xenopus tadpoles serves as an experimental model system for mucociliary epithelia (mce) such as the human airway epithelium. mces are characterized by the presence of mucus-secreting goblet and multiciliated cells (mccs). a third cell type, ion-secreting cells (iscs), is present in the larval skin as well. synchronized beating of mcc cilia is required for directional transport of mucus. here we describe a novel cell type in the xenopus laevis larval epidermis, characterized ...	2014	24598162
kcnt1 gain of function in 2 epilepsy phenotypes is reversed by quinidine.	mutations in kcnt1 have been implicated in autosomal dominant nocturnal frontal lobe epilepsy (adnfle) and epilepsy of infancy with migrating focal seizures (eimfs). more recently, a whole exome sequencing study of epileptic encephalopathies identified an additional de novo mutation in 1 proband with eimfs. we aim to investigate the electrophysiological and pharmacological characteristics of hkcnt1 mutations and examine developmental expression levels.	2014	24591078
the effects of pesticide exposure on ultraviolet-b radiation avoidance behavior in tadpoles.	effects of contaminants on behavior may have important consequences on wildlife populations because behaviors such as predation, predator avoidance, reproduction, and social interaction can affect population dynamics. as a common environmental stressor, ultraviolet-b (uvb) radiation causes various deleterious effects and some aquatic organisms actively avoid uvb radiation in water. however, the extent to which environmental contaminants can impair uvb avoidance has not been evaluated, which may ...	2014	24589757
a voltage dependent non-inactivating na+ channel activated during apoptosis in xenopus oocytes.	ion channels in the plasma membrane are important for the apoptotic process. different types of voltage-gated ion channels are up-regulated early in the apoptotic process and block of these channels prevents or delays apoptosis. in the present investigation we examined whether ion channels are up-regulated in oocytes from the frog xenopus laevis during apoptosis. the two-electrode voltage-clamp technique was used to record endogenous ion currents in the oocytes. during staurosporine-induced apop ...	2014	24586320
generation of recombinant antibodies to rat gabaa receptor subunits by affinity selection on synthetic peptides.	the abundance and physiological importance of gabaa receptors in the central nervous system make this neurotransmitter receptor an attractive target for localizing diagnostic and therapeutic biomolecules. gabaa receptors are expressed within the retina and mediate synaptic signaling at multiple stages of the visual process. to generate monoclonal affinity reagents that can specifically recognize gabaa receptor subunits, we screened two bacteriophage m13 libraries, which displayed human scfvs, by ...	2014	24586298
disulfide cross-linking of transport and trimerization domains of a neuronal glutamate transporter restricts the role of the substrate to the gating of the anion conductance.	excitatory amino acid transporters remove synaptically released glutamate and maintain its concentrations below neurotoxic levels. eaats also mediate a thermodynamically uncoupled substrate-gated anion conductance that may modulate cell excitability. a structure of an archeal homologue, which reflects an early intermediate on the proposed substrate translocation path, has been suggested to be similar to an anion conducting conformation. to probe this idea by functional studies, we have introduce ...	2014	24584931
engineering xenopus embryos for phenotypic drug discovery screening.	many rare human inherited diseases remain untreatable despite the fact that the disease causing genes are known and adequate mouse disease models have been developed. in vivo phenotypic drug screening relies on isolating drug candidates by their ability to produce a desired therapeutic phenotype in whole organisms. embryos of zebrafish and xenopus frogs are abundant, small and free-living. they can be easily arrayed in multi-well dishes and treated with small organic molecules. with the developm ...	2014	24576445
hplc-based activity profiling for gabaa receptor modulators in adenocarpus cincinnatus.	in a two-microelectrode voltage clamp assay with xenopus laevis oocytes, a dichloromethane extract of adenocarpus cincinnatus roots and tubers (leguminosae) enhanced the gaba-induced chloride current (igaba) through receptors of the subtype α1β2γ2s by 126.5 ± 25.1% when tested at 100 μg/ml. by means of hplc-based activity profiling, 15 flavonoid and isoflavonoid derivatives, including eight new compounds, were identified in the active fractions of the extract. isoflavone 11 and pterocarpans 2 an ...	2014	24571311
ras-dva1 small gtpase regulates telencephalon development in xenopus laevis embryos by controlling fgf8 and agr signaling at the anterior border of the neural plate.	we previously found that the small gtpase ras-dva1 is essential for the telencephalic development in xenopus laevis because ras-dva1 controls the fgf8-mediated induction of foxg1 expression, a key telencephalic regulator. in this report, we show, however, that ras-dva1 and foxg1 are expressed in different groups of cells; whereas ras-dva1 is expressed in the outer layer of the anterior neural fold, foxg1 and fgf8 are activated in the inner layer from which the telencephalon is derived. we resolv ...	2014	24570397
structure-function elucidation of a new α-conotoxin, lo1a, from conus longurionis.	α-conotoxins are peptide toxins found in the venom of marine cone snails and potent antagonists of various subtypes of nicotinic acetylcholine receptors (nachrs). nachrs are cholinergic receptors forming ligand-gated ion channels in the plasma membranes of certain neurons and the neuromuscular junction. because nachrs have an important role in regulating transmitter release, cell excitability, and neuronal integration, nachr dysfunctions have been implicated in a variety of severe pathologies su ...	2014	24567324
methods for the study of caspase activation in the xenopus laevis oocyte and egg extract.	the study of apoptosis and caspases has advanced greatly over recent decades. studies conducted in the xenopus laevis egg extract and oocyte model system have significantly contributed to these advances. twenty years ago, newmeyer and colleagues first showed that the x. laevis egg extract, when incubated at room temperature, reconstituted the key molecular events of cellular apoptosis including cytochrome c release, nuclear condensation, internucleosomal fragmentation, and caspase activation. th ...	2014	24567099
the cryocapsule: simplifying correlative light to electron microscopy.	correlating complementary multiple scale images of the same object is a straightforward means to decipher biological processes. light microscopy and electron microscopy are the most commonly used imaging techniques, yet despite their complementarity, the experimental procedures available to correlate them are technically complex. we designed and manufactured a new device adapted to many biological specimens, the cryocapsule, that simplifies the multiple sample preparation steps, which at present ...	2014	24533564
rfx7 is required for the formation of cilia in the neural tube.	regulatory factor x (rfx) transcription factors are important for development and are likely involved in the pathogenesis of serious human diseases including ciliopathies. while seven rfx genes have been identified in vertebrates and several rfx transcription factors have been reported to be regulators of ciliogenesis, the role of rfx7 in development including ciliogenesis is not known. here we show that rfx7 in xenopus laevis is expressed in the neural tube, eye, otic vesicles, and somites. kno ...	2014	24530844
evidence for expression and function of angiotensin ii receptor type 1 in pulmonary epithelial cells.	there is a growing evidence that the peptide hormone angiotensin ii (angii) can act as an auto-/paracrine mediator to regulate epithelial ion transport processes. the present study focused on the impact of angii on transepithelial ion transport in pulmonary epithelia. transcripts for the angii receptor type 1 (atr1) were detected in lungs of xenopus laevis and h441 cells (human pulmonary epithelial cell line). native xenopus lung preparations were used for ussing chamber recordings and apically ...	2014	24530803
changes in oscillatory dynamics in the cell cycle of early xenopus laevis embryos.	during the early development of xenopus laevis embryos, the first mitotic cell cycle is long (∼85 min) and the subsequent 11 cycles are short (∼30 min) and clock-like. here we address the question of how the cdk1 cell cycle oscillator changes between these two modes of operation. we found that the change can be attributed to an alteration in the balance between wee1/myt1 and cdc25. the change in balance converts a circuit that acts like a positive-plus-negative feedback oscillator, with spikes o ...	2014	24523664
wiring the retinal circuits activated by light during early development.	light information is sorted by neuronal circuits to generate image-forming (if) (interpretation and tracking of visual objects and patterns) and non-image-forming (nif) tasks. among the nif tasks, photic entrainment of circadian rhythms, the pupillary light reflex, and sleep are all associated with physiological responses, mediated mainly by a small group of melanopsin-expressing retinal ganglion cells (mrgcs). using xenopus laevis as a model system, and analyzing the c-fos expression induced by ...	2014	24521229
degradation of m(r) 25,000 protein by cathepsin l-like protease in xenopus laevis oocytes.	a phosphorylated protein with a molecular mass of 25,000 (pp25) is involved in xenopus laevis vitellogenin b1 and partially overlaps with phosvitin and lipovitellin 2. the protease responsible for pp25 degradation was studied in vitro since this occurs during embryogenesis. initially, a protease thought to be a contaminant of the purified pp25 preparation was analyzed and an antipain-sensitive protease presumed to be involved. when commercially available proteases were examined, pp25 was not deg ...	2014	24510540