Publications

acetylcholine promotes binding of α-conotoxin mii at α3 β2 nicotinic acetylcholine receptors.	α-conotoxin mii (α-ctxmii) is a 16-residue peptide with the sequence gccsnpvchlehsnlc, containing cys2-cys8 and cys3-cys16 disulfide bonds. this peptide, isolated from the venom of the marine cone snail conus magus, is a potent and selective antagonist of neuronal nicotinic acetylcholine receptors (nachrs). to evaluate the impact of channel-ligand interactions on ligand-binding affinity, homology models of the heteropentameric α3β2-nachr were constructed. the models were created in modeller with ...	2014	24420650
time-lapse x-ray phase-contrast microtomography for in vivo imaging and analysis of morphogenesis.	x-ray phase-contrast microtomography (xpcμt) is a label-free, high-resolution imaging modality for analyzing early development of vertebrate embryos in vivo by using time-lapse sequences of 3d volumes. here we provide a detailed protocol for applying this technique to study gastrulation in xenopus laevis (african clawed frog) embryos. in contrast to μmri, xpcμt images optically opaque embryos with subminute temporal and micrometer-range spatial resolution. we describe sample preparation, culture ...	2014	24407356
the role of voltage-gated calcium channels in neurotransmitter phenotype specification: coexpression and functional analysis in xenopus laevis.	calcium activity has been implicated in many neurodevelopmental events, including the specification of neurotransmitter phenotypes. higher levels of calcium activity lead to an increased number of inhibitory neural phenotypes, whereas lower levels of calcium activity lead to excitatory neural phenotypes. voltage-gated calcium channels (vgccs) allow for rapid calcium entry and are expressed during early neural stages, making them likely regulators of activity-dependent neurotransmitter phenotype ...	2014	24477801
plakophilin-3 catenin associates with the etv1/er81 transcription factor to positively modulate gene activity.	members of the plakophilin-catenin sub-family (pkp-1, -2, and -3) facilitate the linkage of desmosome junctional components to each other (e.g. desmosomal cadherins to desmoplakin) and the intermediate-filament cytoskeleton. pkps also contribute to desmosomal stabilization and the trafficking of its components. the functions of pkps outside of the desmosome are less well studied, despite evidence suggesting their roles in mrna regulation, small-gtpase modulation (e.g. mid-body scission) during c ...	2014	24475179
nedd4-2 regulates surface expression and may affect n-glycosylation of hyperpolarization-activated cyclic nucleotide-gated (hcn)-1 channels.	hcn channels are important regulators of neuronal excitability. the proper function of these channels is governed by various mechanisms, including post-translational modifications of channel subunits. here, we provide evidence that ubiquitination via a ubiquitin ligase, neuronal precursor cell expressed developmentally downregulated (nedd)-4-2, is involved in the regulation of hyperpolarization-activated cyclic nucleotide-gated (hcn) channels. we identified a py motif (l/ppxy), the characteristi ...	2014	24451387
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
co2 transport by pip2 aquaporins of barley.	co2 permeability of plasma membrane intrinsic protein 2 (pip2) aquaporins of hordeum vulgare l. was investigated. five pip2 members were heterologously expressed in xenopus laevis oocytes. co2 permeability was determined by decrease of cytosolic ph in co2-enriched buffer using a hydrogen ion-selective microelectrode. hvpip2;1, hvpip2;2, hvpip2;3 and hvpip2;5 facilitated co2 transport across the oocyte cell membrane. however, hvpip2;4 that is highly homologous to hvpip2;3 did not. the isoleucine ...	2014	24406630
maintenance of multipotency in human dermal fibroblasts treated with xenopus laevis egg extract requires exogenous fibroblast growth factor-2.	direct reprogramming of a differentiated somatic cell into a developmentally more plastic cell would offer an alternative to applications in regenerative medicine that currently depend on either embryonic stem cells (escs), adult stem cells, or induced pluripotent stem cells (ipscs). here we report the potential of select xenopus laevis egg extract fractions, in combination with exogenous fibroblast growth factor-2 (fgf2), to affect life span, morphology, gene expression, protein translation, an ...	2014	24405062
rem2 is an activity-dependent negative regulator of dendritic complexity in vivo.	a key feature of the cns is structural plasticity, the ability of neurons to alter their morphology and connectivity in response to sensory experience and other changes in the environment. how this structural plasticity is achieved at the molecular level is not well understood. we provide evidence that changes in sensory experience simultaneously trigger multiple signaling pathways that either promote or restrict growth of the dendritic arbor; structural plasticity is achieved through a balance ...	2014	24403140
rare human nicotinic acetylcholine receptor α4 subunit (chrna4) variants affect expression and function of high-affinity nicotinic acetylcholine receptors.	nicotine, the primary psychoactive component in tobacco smoke, produces its behavioral effects through interactions with neuronal nicotinic acetylcholine receptors (nachrs). α4β2 nachrs are the most abundant in mammalian brain, and converging evidence shows that this subtype mediates the rewarding and reinforcing effects of nicotine. a number of rare variants in the chrna4 gene that encode the α4 nachr subunit have been identified in human subjects and appear to be underrepresented in a cohort o ...	2014	24385388
retinoic acid regulation by cyp26 in vertebrate lens regeneration.	xenopus laevis is among the few species that are capable of fully regenerating a lost lens de novo. this occurs upon removal of the lens, when secreted factors from the retina are permitted to reach the cornea epithelium and trigger it to form a new lens. although many studies have investigated the retinal factors that initiate lens regeneration, relatively little is known about what factors support this process and make the cornea competent to form a lens. we presently investigate the role of r ...	2014	24384390
identification of dihydrostilbenes in pholidota chinensis as a new scaffold for gabaa receptor modulators.	a dichloromethane extract of stems and roots of pholidota chinensis (orchidaceae) enhanced gaba-induced chloride currents (i(gaba)) by 132.75 ± 36.69% when tested at 100 μg/ml in a two-microelectrode voltage clamp assay, on xenopus laevis oocytes expressing recombinant α₁β₂γ₂s gaba(a) receptors. by means of an hplc-based activity profiling approach, the three structurally related stilbenoids coelonin (1), batatasin iii (2), and pholidotol d (3) were identified in the active fractions of the extr ...	2014	24462176
cartilage derived morphogenetic protein 2 - a potential therapy for intervertebral disc regeneration?	low back pain is amongst the top ten risk factors that contribute to disability, ranking higher than diabetes and mental health disease globally as a contributor to years lost to disability (yld), and escalating as western societies age. abundant evidence suggests that intervertebral disc (ivd) damage is central to the origin of pain in the spine. ivd degeneration involves the progressive deterioration of the highly organized disc tissue extracellular matrix, losing its elasticity and hence its' ...	2014	24457196
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
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
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
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
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
short term exposure to multi-walled carbon nanotubes induce oxidative stress and dna damage in xenopus laevis tadpoles.	the potential impact of multiwalled carbon nanotubes (mwcnts) was investigated on xenopus laevis tadpoles exposed to 0.1, 1 and 10mg/l. oxidative stress was measured in entire larvae exposed and dna damage (comet assay) was carried out in erythrocytes of circulating blood from 2h to 24h according to standardized recommendations. results showed significant h2o2 production when larvae were exposed to 1mg/l and 10mg/l of mwcnts after 4h and 2h of exposure, respectively. antioxidant enzyme activitie ...	2014	24905693
efficient modulation of γ-aminobutyric acid type a receptors by piperine derivatives.	piperine activates trpv1 (transient receptor potential vanilloid type 1 receptor) receptors and modulates γ-aminobutyric acid type a receptors (gabaar). we have synthesized a library of 76 piperine analogues and analyzed their effects on gabaar by means of a two-microelectrode voltage-clamp technique. gabaar were expressed in xenopus laevis oocytes. structure-activity relationships (sars) were established to identify structural elements essential for efficiency and potency. efficiency of piperin ...	2014	24905252
a single codon insertion in picalm is associated with development of familial subvalvular aortic stenosis in newfoundland dogs.	familial subvalvular aortic stenosis (sas) is one of the most common congenital heart defects in dogs and is an inherited defect of newfoundlands, golden retrievers and human children. although sas is known to be inherited, specific genes involved in newfoundlands with sas have not been defined. we hypothesized that sas in newfoundlands is inherited in an autosomal dominant pattern and caused by a single genetic variant. we studied 93 prospectively recruited newfoundland dogs, and 180 control do ...	2014	24898977
a prominent role for invariant t cells in the amphibian xenopus laevis tadpoles.	invariant t (it) cells expressing an invariant or semi-invariant t cell receptor (tcr) repertoire have gained attention in recent years because of their potential as specialized regulators of immune function. these it cells are typically restricted by nonclassical mhc class i molecules (e.g., cd1d and mr1) and undergo differentiation pathways distinct from conventional t cells. while the benefit of a limited tcr repertoire may appear counterintuitive in regard to the advantage of the diversified ...	2014	24898512
metabolic engineering of pichia pastoris for production of hyaluronic acid with high molecular weight.	the high molecular weight (>1 mda) of hyaluronic acid (ha) is important for its biological functions. the reported limiting factors for the production of ha with high molecular weight (mw) by microbial fermentation are the insufficient ha precursor pool and cell growth inhibition. to overcome these issues, the xenopus laevis xhasa2 and xhasb genes encoding hyaluronan synthase 2 (xhasa2) and udp-glucose dehydrogenase (xhasb), were expressed in pichia pastoris widely used for production of heterol ...	2014	24892811
genome-wide expression profile of the response to spinal cord injury in xenopus laevis reveals extensive differences between regenerative and non-regenerative stages.	xenopus laevis has regenerative and non-regenerative stages. as a tadpole, it is fully capable of functional recovery after a spinal cord injury, while its juvenile form (froglet) loses this capability during metamorphosis. we envision that comparative studies between regenerative and non-regenerative stages in xenopus could aid in understanding why spinal cord regeneration fails in human beings.	2014	24885550
gymnemic acids inhibit sodium-dependent glucose transporter 1.	to evaluate the activity of botanicals used in chinese traditional medicine as hypoglycemic agents for diabetes type ii prevention and/or treatment, extracts prepared from 26 medicinal herbs were screened for their inhibitory activity on sodium-dependent glucose transporter 1 (sglt1) by using two-electrode voltage-clamp recording of glucose uptake in xenopus laevis oocytes microinjected with crna for sglt1. showing by far the strongest sglt1 inhibitory effect, the phytochemicals extracted from g ...	2014	24856809
rapid hebbian axonal remodeling mediated by visual stimulation.	we examined how correlated firing controls axon remodeling, using in vivo time-lapse imaging and electrophysiological analysis of individual retinal ganglion cell (rgc) axons that were visually stimulated either synchronously or asynchronously relative to neighboring inputs in the xenopus laevis optic tectum. rgcs stimulated out of synchrony rapidly lost the ability to drive tectal postsynaptic partners while their axons grew and added many new branches. in contrast, synchronously activated rgcs ...	2014	24855269
male-male clasping may be part of an alternative reproductive tactic in xenopus laevis.	male xenopus laevis frogs have been observed to clasp other males in a sustained, amplectant position, the purpose of which is unknown. we examined three possible hypotheses for this counter-intuitive behavior: 1) clasping males fail to discriminate the sex of the frogs they clasp; 2) male-male clasping is an aggressive or dominant behavior; or 3) that males clasp other males to gain proximity to breeding events and possibly engage in sperm competition. our data, gathered through a series of beh ...	2014	24849114
proteolytic activation of the human epithelial sodium channel by trypsin iv and trypsin i involves distinct cleavage sites.	proteolytic activation is a unique feature of the epithelial sodium channel (enac). however, the underlying molecular mechanisms and the physiologically relevant proteases remain to be identified. the serine protease trypsin i can activate enac in vitro but is unlikely to be the physiologically relevant activating protease in enac-expressing tissues in vivo. herein, we investigated whether human trypsin iv, a form of trypsin that is co-expressed in several extrapancreatic epithelial cells with e ...	2014	24841206
anillin regulates cell-cell junction integrity by organizing junctional accumulation of rho-gtp and actomyosin.	anillin is a scaffolding protein that organizes and stabilizes actomyosin contractile rings and was previously thought to function primarily in cytokinesis [1-10]. using xenopus laevis embryos as a model system to examine anillin's role in the intact vertebrate epithelium, we find that a population of anillin surprisingly localizes to epithelial cell-cell junctions throughout the cell cycle, whereas it was previously thought to be nuclear during interphase [5, 11]. furthermore, we show that anil ...	2014	24835458
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
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
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
retinoic acid induced-1 (rai1) regulates craniofacial and brain development in xenopus.	retinoic acid induced-1 (rai1) is an important yet understudied histone code reader that when mutated in humans results in smith-magenis syndrome (sms), a neurobehavioral disorder accompanied by signature craniofacial abnormalities. despite previous studies in mouse and human cell models, very little is known about the function of rai1 during embryonic development. in the present study, we have turned to the model vertebrates xenopus laevis and xenopus tropicalis to better understand the develop ...	2014	24878353
xenopus cadherin 5 is specifically expressed in endothelial cells of the developing vascular system.	vasculogenesis is an important, multistep process leading to the formation of a functional primary network of blood vessels in the developing embryo. a series of interactions between secreted growth factors and their specific receptors leads to the specification of mesodermal cells to become hemangioblasts, which then differentiate into angioblasts. these subsequently proliferate, coalesce into cords and finally form tubular vascular structures. for proper function of these primary blood vessels ...	2014	24860995
expression pattern of zcchc24 during early xenopus development.	we report the expression pattern of a novel xenopus laevis gene, zcchc24, which encodes a protein containing two zinc finger domains from the zf-cchc and zf-3cxxc superfamilies. this protein shares >84% amino acid identity with its vertebrate homologues. during x. laevis embryonic development, zcchc24 is expressed at gastrula stages in the dorsal mesoderm, including the cardiac precursors region. during neurula stages, zcchc24 is expressed as two stripes in the dorsal region, more precisely, in ...	2014	24860994
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
retrograde intraciliary trafficking of opsin during the maintenance of cone-shaped photoreceptor outer segments of xenopus laevis.	photoreceptor outer segments (oss) are essential for our visual perception, and take either rod or cone forms. the cell biological basis for the formation of rods is well established; however, the mechanism of cone formation is ill characterized. while xenopus rods are called rods, they exhibit cone-shaped oss during the early process of development. to visualize the dynamic reorganization of disk membranes, opsin and peripherin/rds were fused to a fluorescent protein, dendra2, and expressed in ...	2014	24855015
spatiotemporal lipid profiling during early embryo development of xenopus laevis using dynamic tof-sims imaging.	time-of-flight secondary ion mass spectrometry (tof-sims) imaging has been used for the direct analysis of single intact xenopus laevis embryo surfaces, locating multiple lipids during fertilization and the early embryo development stages with subcellular lateral resolution (∼4 μm). the method avoids the complicated sample preparation for lipid analysis of the embryos, which requires selective chemical extraction of a pool of samples and chromatographic separation, while preserving the spatial d ...	2014	24852167
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
yap1, transcription regulator in the hippo signaling pathway, is required for xenopus limb bud regeneration.	the hippo signaling pathway is conserved from insects to mammals and is important for multiple processes, including cell proliferation, apoptosis and tissue homeostasis. hippo signaling is also crucial for regeneration, including intercalary regeneration, of the whole body in the flatworm and of the leg in the cricket. however, its role in vertebrate epimorphic regeneration is unknown. therefore, to identify principles of regeneration that are conserved among bilaterians, we investigated the rol ...	2014	24491818
left-right patterning in xenopus conjoined twin embryos requires serotonin signaling and gap junctions.	a number of processes operating during the first cell cleavages enable the left-right (lr) axis to be consistently oriented during xenopus laevis development. prior work showed that secondary organizers induced in frog embryos after cleavage stages (i.e. conjoined twins arising from ectopic induced primary axes) correctly pattern their own lr axis only when a primary (early) organizer is also present. this instructive effect confirms the unique lr patterning functions that occur during early emb ...	2014	25896280
optogenetics in developmental biology: using light to control ion flux-dependent signals in xenopus embryos.	developmental bioelectricity, electrical signaling among non-excitable cells, is now known to regulate proliferation, apoptosis, gene expression, and patterning during development. the extraordinary temporal and spatial resolution offered by optogenetics could revolutionize the study of bioelectricity the same way it has revolutionized neuroscience. there is, however, no guide to adapting optogenetics to patterning systems. to fill this gap, we used optogenetic reagents, both proteins and photoc ...	2014	25896279
transmembrane signal transduction in oocyte maturation and fertilization: focusing on xenopus laevis as a model animal.	fertilization is a cell biological phenomenon of crucial importance for the birth of new life in a variety of multicellular and sexual reproduction species such as algae, animal and plants. fertilization involves a sequence of events, in which the female gamete "egg" and the male gamete "spermatozoon (sperm)" develop, acquire their functions, meet and fuse with each other, to initiate embryonic and zygotic development. here, it will be briefly reviewed how oocyte cytoplasmic components are orche ...	2014	25546390