Publications

toxic mechanisms of copper oxide nanoparticles in epithelial kidney cells.	cuo nps have previously been reported as toxic to a range of cell cultures including kidney epithelial cells from the frog, xenopus laevis (a6). here we examine the molecular mechanisms affecting toxicity of cu in different forms and particle sizes. a6 cells were exposed to ionic cu (cu2+) or cuo particles of three different sizes: cuo nps of 6 nm (np6), larger poly-dispersed cuo nps of <100 nm (poly) and cuo micro particles of <5 μm (micro), at 200 μm, equal to 12.7 mg cu/l. poly was significan ...	2015	25862124
a requirement for hedgehog signaling in thyroid hormone-induced postembryonic intestinal remodeling.	intestinal remodeling during amphibian metamorphosis has long been studied as a model for the formation of the adult organs in vertebrates, especially the formation of adult organ-specific stem cells. like all other processes during metamorphosis, this process is controlled by thyroid hormone (t3), which affects cell fate and behavior through transcriptional regulation of target genes by binding to t3 receptors (trs). earlier studies have shown that sonic hedgehog (shh) is induced by t3 in the d ...	2015	25859319
functional characterization of the human facilitative glucose transporter 12 (glut12) by electrophysiological methods.	glut12 is a member of the facilitative family of glucose transporters. the goal of this study was to characterize the functional properties of glut12, expressed in xenopus laevis oocytes, using radiotracer and electrophysiological methods. our results showed that glut12 is a facilitative sugar transporter with substrate selectivity: d-glucose ≥ α-methyl-d-glucopyranoside (α-mg) > 2-deoxy-d-glucose(2-dog) > d-fructose = d-galactose. α-mg is a characteristic substrate of the na(+)/glucose (sglt) f ...	2015	25855082
atp4a is required for development and function of the xenopus mucociliary epidermis - a potential model to study proton pump inhibitor-associated pneumonia.	proton pump inhibitors (ppis), which target gastric h(+)/k(+)atpase (atp4), are among the most commonly prescribed drugs. ppis are used to treat ulcers and as a preventative measure against gastroesophageal reflux disease in hospitalized patients. ppi treatment correlates with an increased risk for airway infections, i.e. community- and hospital-acquired pneumonia. the cause for this correlation, however, remains elusive. the xenopus embryonic epidermis is increasingly being used as a model to s ...	2015	25848696
dissecting microtubule structures by laser ablation.	here, we describe a detailed protocol, based on laser ablation and fluorescence optical microscopy, to measure the microtubule organization in spindles, including microtubule length distribution, polarity, and plus and minus end densities. the method uses the asymmetry in microtubule depolymerization after a cut, where the newly created microtubule plus ends depolymerize all the way to the minus ends, whereas the newly created minus ends remain stable. the protocol described in this chapter is o ...	2015	25640424
expression of a novel serine/threonine kinase gene, ulk4, in neural progenitors during xenopus laevis forebrain development.	we have analyzed the expression pattern of a novel serine/threonine kinase gene ulk4 during forebrain development in xenopus laevis. to this aim, we firstly cloned a ulk4 cdna fragment from x.laevis and generated a rna probe that was used for its detection by in situ hybridization. throughout development xulk4 expression was detected along the ventricular (vz) and subventricular zones (svz) of all forebrain regions, with the exception of the vz of the striatum. in the adult, xulk4 was also mainl ...	2015	25637795
distinct patterns of endosulfatase gene expression during xenopus laevis limb development and regeneration.	the heparan sulfate 6-o-endosulfatases sulf1 and sulf2 regulate multiple cellular processes and organ development. sulfs modulate a range of heparan-sulfate-dependent extracellular pathways, including the fibroblast growth factor, bone morphogenetic protein, and wingless/wnt signaling pathways. known patterns of sulf transcript expression together with functional experiments have implicated the sulfs in chondrogenesis and muscle regeneration in mammals. here, we describe the expression patterns ...	2015	27499864
the effects of simazine, a chlorotriazine herbicide, on the expression of genes in developing male xenopus laevis.	simazine was investigated for gene expression concurrent with simazine-induced phenotype changes during development of male xenopus laevis. x. laevis tadpoles (nieuwkoop-faber stage 46) were exposed to 0.1, 1.2, 11.0 and 100.9 μg/l simazine for 100 days. the results showed that an increased mortality of x. laevis, decreased gonad weight and altered gonadosomatic index of males significantly (p<0.05) when exposed to simazine at 11.0 and 100.9 µg/l. significant degeneration in testicular tissues w ...	2015	25634327
acute toxic effects of the herbicide formulation and the active ingredient used in cycloxydim-tolerant maize cultivation on embryos and larvae of the african clawed frog, xenopus laevis.	most genetically engineered herbicide-tolerant crops are still awaiting approval in europe. there is, however, a recent trend for the cultivation of cycloxydim-tolerant maize hybrids for use in maize production. we studied the acute toxic effects of the complementary herbicide focus(®) ultra and its active ingredient cycloxydim on embryos and early-stage larvae of the african clawed frog (xenopus laevis). the results indicate that the herbicide formulation is significantly more toxic than the ac ...	2015	25634323
α- and β-subunit composition of voltage-gated sodium channels investigated with μ-conotoxins and the recently discovered μo§-conotoxin gviij.	we investigated the identities of the isoforms of the α (nav1)- and β (navβ)-subunits of voltage-gated sodium channels, including those responsible for action potentials in rodent sciatic nerves. to examine α-subunits, we used seven μ-conotoxins, which target site 1 of the channel. with the use of exogenously expressed channels, we show that two of the μ-conotoxins, μ-buiiib and μ-sxiiia, are 50-fold more potent in blocking nav1.6 from mouse than that from rat. furthermore, we observed that μ-bu ...	2015	25632083
hydrogen sulfide decreases β-adrenergic agonist-stimulated lung liquid clearance by inhibiting enac-mediated transepithelial sodium absorption.	in pulmonary epithelia, β-adrenergic agonists regulate the membrane abundance of the epithelial sodium channel (enac) and, thereby, control the rate of transepithelial electrolyte absorption. this is a crucial regulatory mechanism for lung liquid clearance at birth and thereafter. this study investigated the influence of the gaseous signaling molecule hydrogen sulfide (h2s) on β-adrenergic agonist-regulated pulmonary sodium and liquid absorption. application of the h2s-liberating molecule na2s ( ...	2015	25632025
small-molecule high-throughput screening utilizing xenopus egg extract.	screens for small-molecule modulators of biological pathways typically utilize cultured cell lines, purified proteins, or, recently, model organisms (e.g., zebrafish, drosophila, c. elegans). herein, we describe a method for using xenopus laevis egg extract, a biologically active and highly tractable cell-free system that recapitulates a legion of complex chemical reactions found in intact cells. specifically, we focus on the use of a luciferase-based fusion system to identify small-molecule mod ...	2015	25618336
the wnt receptor frizzled-4 modulates adam13 metalloprotease activity.	cranial neural crest (cnc) cells are a transient population of stem cells that originate at the border of the neural plate and the epidermis, and migrate ventrally to contribute to most of the facial structures including bones, cartilage, muscles and ganglia. adam13 is a cell surface metalloprotease that is essential for cnc cell migration. here, we show in xenopus laevis embryos that the wnt receptor fz4 binds to the cysteine-rich domain of adam13 and negatively regulates its proteolytic activi ...	2015	25616895
temporal and spatial expression analysis of peripheral myelin protein 22 (pmp22) in developing xenopus.	peripheral myelin protein 22 (pmp22), a member of the junction protein family claudin/emp/pmp22, contributes to the formation and maintenance of myelin sheaths in the peripheral nervous system. apart from the establishment and maintenance of peripheral nerves, pmp22 and its family member have also participated in a broad range of more general processes including cell cycle regulation and apoptosis during development. pmp22 has been identified from several vertebrate species including mouse, huma ...	2015	25616247
discovery of a novel general anesthetic chemotype using high-throughput screening.	the development of novel anesthetics has historically been a process of combined serendipity and empiricism, with most recent new anesthetics developed via modification of existing anesthetic structures.	2015	25603205
highly efficient gene knockout by injection of talen mrnas into oocytes and host transfer in xenopus laevis.	zinc-finger nucleases, transcription activator-like effector nucleases (talens) and the crispr/cas (clustered regularly interspaced short palindromic repeats/crispr-associated proteins) system are potentially powerful tools for producing tailor-made knockout animals. however, their mutagenic activity is not high enough to induce mutations at all loci of a target gene throughout an entire tadpole. in this study, we present a highly efficient method for introducing gene modifications at almost all ...	2015	25596277
structural analysis of dopamine- and amphetamine-induced depolarization currents in the human dopamine transporter.	amphetamine (amph) induces depolarizing currents through the human dopamine transporter (hdat). recently we discovered that the s(+) enantiomer of amph induces a current through hdat that persists long after its removal from the external milieu. the persistent current is less prominent for r(-)amph and essentially absent for dopamine (da)-induced currents. related agents such as methamphetamine also exhibit persistent currents, which are present in both frog oocyte and mammalian hek expression s ...	2015	25594379
trpp2-dependent ca2+ signaling in dorso-lateral mesoderm is required for kidney field establishment in xenopus.	in xenopus laevis embryos, kidney field specification is dependent on retinoic acid (ra) and coincides with a dramatic increase of ca(2+) transients, but the role of ca(2+) signaling in the kidney field is unknown. here, we identify trpp2, a member of the transient receptor potential (trp) superfamily of channel proteins encoded by the pkd2 gene, as a central component of ca(2+) signaling in the kidney field. trpp2 is strongly expressed at the plasma membrane where it might regulate extracellula ...	2015	25588842
pan-african phylogeography of a model organism, the african clawed frog 'xenopus laevis'.	the african clawed frog xenopus laevis has a large native distribution over much of sub-saharan africa and is a model organism for research, a proposed disease vector, and an invasive species. despite its prominent role in research and abundance in nature, surprisingly little is known about the phylogeography and evolutionary history of this group. here, we report an analysis of molecular variation of this clade based on 17 loci (one mitochondrial, 16 nuclear) in up to 159 individuals sampled th ...	2015	25583226
interactive effects of ultraviolet-b radiation and pesticide exposure on dna photo-adduct accumulation and expression of dna damage and repair genes in xenopus laevis embryos.	pesticide use and ultraviolet-b (uvb) radiation have both been suggested to adversely affect amphibians; however, little is known about their interactive effects. one potential adverse interaction could involve pesticide-induced dysregulation of dna repair pathways, resulting in greater numbers of dna photo-adducts from uvb exposure. in the present study, we investigated the interactive effects of uvb radiation and two common pesticides (endosulfan and α-cypermethrin) on induction of dna photo-a ...	2015	25569846
effects on channel properties and induction of cell death induced by c-terminal truncations of pannexin1 depend on domain length.	pannexin1 (panx1) is an integral membrane protein and known to form multifunctional hexameric channels. recently, panx1 was identified to be responsible for the release of atp and utp from apoptotic cells after site-specific proteolysis by caspases 3/7. cleavage at the carboxy-terminal (ct) position aa 376-379 irreversibly opens human panx1 channels and leads to the release of the respective nucleotides resulting in recruitment of macrophages and in subsequent activation of the immunologic respo ...	2015	25567359
desflurane increased the activity of excitatory amino-acid carrier 1 (eaac1) expressed in xenopus oocytes.	desflurane is a volatile anaesthetic agent with neuroprotective properties. excitatory amino-acid carrier 1 (eaac1) may be neuroprotective by taking up glutamate and cysteine. therefore, the effects of desflurane on eaac1 activity were investigated in this study. eaac1 was expressed in xenopus laevis oocytes. two-electrode voltage-clamping technique was used to record membrane currents upon exposure to l-glutamate (30 μm) in the presence or absence of desflurane (0.4, 1.0, 2.0, 2.6, or 3.2mm). c ...	2015	25840279
in vivo investigation of cilia structure and function using xenopus.	cilia are key organelles in development and homeostasis. the ever-expanding complement of cilia associated proteins necessitates rapid and tractable models for in vivo functional investigation. xenopus laevis provides an attractive model for such studies, having multiple ciliated populations, including primary and multiciliated tissues. the rapid external development of xenopus and the large cells make it an especially excellent platform for imaging studies. here we present embryological and cel ...	2015	25837389
reproductive strategies of the kangaroo leech, marsupiobdella africana (glossiphoniidae).	the kangaroo leech, marsupiobdella africana, is a hermaphroditic organism, with insemination taking place by the planting of a spermatophore on another leech. spermatophores are mostly planted on the anterior of the recipient leech, but not always. several spermatophores may be planted by different leeches on a single recipient. the spermatophore consists of two side by side lobes. within minutes from planting of the spermatophore, the contents are squeezed out and into the body of the recipient ...	2015	25830114
evidence for a revised ion/substrate coupling stoichiometry of gaba transporters.	plasma membrane γ-aminobutyric acid (gaba) transporters (gats) are electrogenic transport proteins that couple the cotranslocation of na(+), cl(-), and gaba across the plasma membrane of neurons and glia. a fundamental property of the transporter that determines its ability to concentrate gaba in cells and, hence, regulate synaptic and extra-synaptic gaba concentrations, is the ion/substrate coupling stoichiometry. here, we scrutinized the currently accepted 2 na(+):1 cl(-):1 gaba stoichiometry ...	2015	25824654
a 90 day safety assessment of genetically modified rice expressing cry1ab/1ac protein using an aquatic animal model.	in fields of transgenic bt rice, frogs are exposed to bt proteins through consumption of both target and nontarget insects. in the present study, we assessed the risk posed by transgenic rice expressing a cry1ab/1ac fusion protein (huahui 1, hh1) on the development of xenopus laevis. for 90 days, froglets were fed a diet with 30% hh1 rice, 30% parental rice (minghui 63, mh63), or no rice as a control. body weight and length were measured every 15 days. after sacrificing the froglets, we performe ...	2015	25822065
toxicity evaluation of a new zn-doped cuo nanocomposite with highly effective antibacterial properties.	the increased resistances to conventional antibiotics determine a strong need for new antibacterials, and specific syntheses at the nanoscale promise to be helpful in this field. a novel zinc-doped copper oxide nanocomposite (nzn-cuo) has been recently sonochemically synthesized and successfully tested also against multi-drug resistant bacteria. after synthesis and characterization of the physicochemical properties, the new nzn-cuo is here evaluated by the frog embyo teratogenesis assay-xenopus ...	2015	25820130
17α-ethinylestradiol can disrupt hemoglobin catabolism in amphibians.	different chemical substances, which enter the environment due to anthropogenic influences, can affect the endocrine system and influence development and physiology of aquatic animals. one of these endocrine disrupting chemicals is the synthetic estrogen, 17α-ethinylestradiol (ee2), which is a main component of various oral contraceptives and demonstrably affects many different aquatic vertebrates at extremely low concentrations by feminization phenomena. the aim of the present study was to inve ...	2015	25819740
an in vivo screen to identify candidate neurogenic genes in the developing xenopus visual system.	neurogenesis in the brain of xenopus laevis continues throughout larval stages of development. we developed a 2-tier screen to identify candidate genes controlling neurogenesis in xenopus optic tectum in vivo. first, microarray and nanostring analyses were used to identify candidate genes that were differentially expressed in sox2-expressing neural progenitor cells or their neuronal progeny. then an in vivo, time-lapse imaging-based screen was used to test whether morpholinos against 34 candidat ...	2015	25818835
crystal structure of a xenopus laevis skin proto-type galectin, close to but distinct from galectin-1.	xenopus laevis (african clawed frog) has two types of proto-type galectins that are similar to mammalian galectin-1 in amino acid sequence. one type, comprising xgalectin-ia and -ib, is regarded as being equivalent to galectin-1, and the other type, comprising xgalectin-va and -vb, is expected to be a unique galectin subgroup. the latter is considerably abundant in frog skin; however, its biological function remains unclear. we determined the crystal structures of two proto-type galectins, xgale ...	2015	25804418
functional characterization of the 1,5-benzodiazepine clobazam and its major active metabolite n-desmethylclobazam at human gaba(a) receptors expressed in xenopus laevis oocytes.	the 1,5-benzodiazepine clobazam is indicated for the adjunctive treatment of seizures associated with lennox-gastaut syndrome in patients 2 years of age or older in the united states, and for treatment of anxiety and various forms of epilepsy elsewhere. clobazam has been reported to exhibit different in vivo adverse effects and addiction liability profile than the classic 1,4-benzodiazepines. in this study, it was investigated whether the in vitro pharmacological properties of clobazam and its m ...	2015	25798598
regeneration of xenopus laevis spinal cord requires sox2/3 expressing cells.	spinal cord regeneration is very inefficient in humans, causing paraplegia and quadriplegia. studying model organisms that can regenerate the spinal cord in response to injury could be useful for understanding the cellular and molecular mechanisms that explain why this process fails in humans. here, we use xenopus laevis as a model organism to study spinal cord repair. histological and functional analyses showed that larvae at pre-metamorphic stages restore anatomical continuity of the spinal co ...	2015	25797152
apoptosis and differentiation of xenopus tail-derived myoblasts by thyroid hormone.	the metamorphosis of anuran amphibians is induced by thyroid hormone (th). to study the molecular mechanisms underlying tail regression during metamorphosis, we established a cell line, xl-b4, from a xenopus laevis tadpole tail at a premetamorphic stage. the cells expressed myoblast markers and differentiated into myotubes in differentiation medium. xl-b4 cells expressing fluorescent proteins were transplanted into tadpole tails. at 5 days post-transplantation, fluorescence was observed in myotu ...	2015	25791374
ensemble-based virtual screening for cannabinoid-like potentiators of the human glycine receptor α1 for the treatment of pain.	the human glycine receptors (hglyrs) are chloride-selective ion channels that mediate inhibitory neurotransmission in the brain stem and spinal cord. they are also targets for compounds of potential use in analgesic therapies. here, we develop a strategy to discover analgesic drugs via structure-based virtual screening based on the recently published nmr structure of the hglyr-α1 transmembrane domain (pdb id: 2m6i ) and the critical role of residue s296 in hglyr-α1 potentiation by δ(9)-tetrahydr ...	2015	25790278
hdac1 regulates the proliferation of radial glial cells in the developing xenopus tectum.	in the developing central nervous system (cns), progenitor cells differentiate into progeny to form functional neural circuits. radial glial cells (rgs) are a transient progenitor cell type that is present during neurogenesis. it is thought that a combination of neural trophic factors, neurotransmitters and electrical activity regulates the proliferation and differentiation of rgs. however, it is less clear how epigenetic modulation changes rg proliferation. we sought to explore the effect of hi ...	2015	25789466
species-specific loss of sexual dimorphism in vocal effectors accompanies vocal simplification in african clawed frogs (xenopus).	phylogenetic studies can reveal patterns of evolutionary change, including the gain or loss of elaborate courtship traits in males. male african clawed frogs generally produce complex and rapid courtship vocalizations, whereas female calls are simple and slow. in a few species, however, male vocalizations are also simple and slow, suggesting loss of male-typical traits. here, we explore features of the male vocal organ that could contribute to loss in two species with simple, slow male calls. in ...	2015	25788725
ear manipulations reveal a critical period for survival and dendritic development at the single-cell level in mauthner neurons.	second-order sensory neurons are dependent on afferents from the sense organs during a critical period in development for their survival and differentiation. past research has mostly focused on whole populations of neurons, hampering progress in understanding the mechanisms underlying these critical phases. to move toward a better understanding of the molecular and cellular basis of afferent-dependent neuronal development, we developed a new model to study the effects of ear removal on a single ...	2015	25787878
a gustatory receptor tuned to d-fructose in antennal sensilla chaetica of helicoverpa armigera.	insect gustatory systems play important roles in food selection and feeding behaviors. in spite of the enormous progress in understanding gustation in drosophila, for other insects one of the key elements in gustatory signaling, the gustatory receptor (gr), is still elusive. in this study, we report that fructose elicits behavioral and physiological responses in helicoverpa armigera (harm) to fructose and identify the gustatory receptor for this sugar. using the proboscis extension reflex (per) ...	2015	25784630
papc mediates self/non-self-distinction during snail1-dependent tissue separation.	cleft-like boundaries represent a type of cell sorting boundary characterized by the presence of a physical gap between tissues. we studied the cleft-like ectoderm-mesoderm boundary in xenopus laevis and zebrafish gastrulae. we identified the transcription factor snail1 as being essential for tissue separation, showed that its expression in the mesoderm depends on noncanonical wnt signaling, and demonstrated that it enables paraxial protocadherin (papc) to promote tissue separation through two n ...	2015	25778923
unique gene expression profile of the proliferating xenopus tadpole tail blastema cells deciphered by rna-sequencing analysis.	organ regenerative ability depends on the animal species and the developmental stage. the molecular bases for variable organ regenerative ability, however, remain unknown. previous studies have identified genes preferentially expressed in the blastema tissues in various animals, but transcriptome analysis of the isolated proliferating blastema cells has not yet been reported. in the present study, we used rna-sequencing analysis to analyze the gene expression profile of isolated proliferating bl ...	2015	25775398
developmentally regulated post-translational modification of nucleoplasmin controls histone sequestration and deposition.	nucleoplasmin (npm) is an abundant histone chaperone in vertebrate oocytes and embryos. during embryogenesis, regulation of npm histone binding is critical for its function in storing and releasing maternal histones to establish and maintain the zygotic epigenome. here, we demonstrate that xenopus laevis npm post-translational modifications (ptms) specific to the oocyte and egg promote either histone deposition or sequestration, respectively. mass spectrometry and npm phosphomimetic mutations us ...	2015	25772360
endogenous gradients of resting potential instructively pattern embryonic neural tissue via notch signaling and regulation of proliferation.	biophysical forces play important roles throughout embryogenesis, but the roles of spatial differences in cellular resting potentials during large-scale brain morphogenesis remain unknown. here, we implicate endogenous bioelectricity as an instructive factor during brain patterning in xenopus laevis. early frog embryos exhibit a characteristic hyperpolarization of cells lining the neural tube; disruption of this spatial gradient of the transmembrane potential (vmem) diminishes or eliminates the ...	2015	25762681
proteomics analysis of xenopus laevis gonad tissue following chronic exposure to atrazine.	atrazine is the most commonly detected pesticide contaminant in ground and surface water. previous studies have shown that atrazine is an endocrine disruptor owing to its adverse effects on the male reproductive system in several vertebrates, but very few molecular mechanisms for these effects have been revealed. in the present study, xenopus laevis were exposed to 100 ppb of atrazine for 120 d, and then the isobaric tags for relative and absolute quantitation (itraq) technique was used to detec ...	2015	25760937
cloning of interleukin-10 from african clawed frog (xenopus tropicalis), with the finding of il-19/20 homologue in the il-10 locus.	interleukin-10 (il-10) is a pleiotropic cytokine that plays an important role in immune system. in the present study, the il-10 gene of african clawed frog (xenopus tropicalis) was first cloned, and its expression pattern and 3d structure were also analyzed. the frog il-10 mrna encoded 172 amino acids which possessed several conserved features found in il-10s from other species, including five-exon/four-intron genomic structure, conserved four cysteine residues, il-10 family motif, and six α-hel ...	2015	25759841
direct observation of ca(2+) -induced calmodulin conformational transitions in intact xenopus laevis oocytes by (19) f nmr spectroscopy.	the ca(2+) -mediated conformational transition of the protein calmodulin (cam) is essential to a variety of signal transduction pathways. whether the transition in living cells is similar to that observed in buffer is not known. here, we report the direct observation by (19) f nmr spectroscopy of the transition of the ca(2+) -free and -bound forms in xenopus laevis oocytes at different ca(2+) levels. we find that the ca(2+) -bound cam population increased greatly upon binding the target protein ...	2015	25753548
efficient retina formation requires suppression of both activin and bmp signaling pathways in pluripotent cells.	retina formation requires the correct spatiotemporal patterning of key regulatory factors. while it is known that repression of several signaling pathways lead to specification of retinal fates, addition of only noggin, a known bmp antagonist, can convert pluripotent xenopus laevis animal cap cells to functional retinal cells. the aim of this study is to determine the intracellular molecular events that occur during this conversion. surprisingly, blocking bmp signaling alone failed to mimic nogg ...	2015	25750435
phospholipase c and d regulation of src, calcium release and membrane fusion during xenopus laevis development.	this review emphasizes how lipids regulate membrane fusion and the proteins involved in three developmental stages: oocyte maturation to the fertilizable egg, fertilization and during first cleavage. decades of work show that phosphatidic acid (pa) releases intracellular calcium, and recent work shows that the lipid can activate src tyrosine kinase or phospholipase c during xenopus fertilization. numerous reports are summarized to show three levels of increase in lipid second messengers inositol ...	2015	25748412
more similar than you think: frog metamorphosis as a model of human perinatal endocrinology.	hormonal control of development during the human perinatal period is critically important and complex with multiple hormones regulating fetal growth, brain development, and organ maturation in preparation for birth. genetic and environmental perturbations of such hormonal control may cause irreversible morphological and physiological impairments and may also predispose individuals to diseases of adulthood, including diabetes and cardiovascular disease. endocrine and molecular mechanisms that reg ...	2015	25744725
xenopus laevis oocytes as a model system for studying the interaction between asbestos fibres and cell membranes.	the mode of interaction of asbestos fibres with cell membranes is still debatable. one reason is the lack of a suitable and convenient cellular model to investigate the causes of asbestos toxicity. we studied the interaction of asbestos fibres with xenopus laevis oocytes, using electrophysiological and morphological methods. oocytes are large single cells, with a limited ability to endocytose molecular ligands; we therefore considered these cells to be a good model for investigating the nature o ...	2015	25745069
rns60, a charge-stabilized nanostructure saline alters xenopus laevis oocyte biophysical membrane properties by enhancing mitochondrial atp production.	we have examined the effects of rns60, a 0.9% saline containing charge-stabilized oxygen nanobubble-based structures. rns60 is generated by subjecting normal saline to taylor-couette-poiseuille (tcp) flow under elevated oxygen pressure. this study, implemented in xenopus laevis oocytes, addresses both the electrophysiological membrane properties and parallel biological processes in the cytoplasm. intracellular recordings from defolliculated x. laevis oocytes were implemented in: (1) air oxygenat ...	2015	25742953
manipulation and in vitro maturation of xenopus laevis oocytes, followed by intracytoplasmic sperm injection, to study embryonic development.	amphibian eggs have been widely used to study embryonic development. early embryonic development is driven by maternally stored factors accumulated during oogenesis. in order to study roles of such maternal factors in early embryonic development, it is desirable to manipulate their functions from the very beginning of embryonic development. conventional ways of gene interference are achieved by injection of antisense oligonucleotides (oligos) or mrna into fertilized eggs, enabling under- or over ...	2015	25742326
a regression-based differential expression detection algorithm for microarray studies with ultra-low sample size.	global gene expression analysis using microarrays and, more recently, rna-seq, has allowed investigators to understand biological processes at a system level. however, the identification of differentially expressed genes in experiments with small sample size, high dimensionality, and high variance remains challenging, limiting the usability of these tens of thousands of publicly available, and possibly many more unpublished, gene expression datasets. we propose a novel variable selection algorit ...	2015	25738861
allosteric modulation of the glycine receptor activated by agonists differing in efficacy.	the glycine receptor (glyr) is the predominant inhibitory neurotransmitter receptor in the brainstem and spinal cord but is also found in higher brain regions. glyr function is affected by a variety of allosteric modulators including drugs of abuse, such as ethanol and inhalants and the ubiquitous divalent cation zinc. two-electrode voltage-clamp experiments were conducted on xenopus laevis oocytes expressing wild-type α1 homomeric glycine receptors to compare the degree of enhancement produced ...	2015	25721789
[on a contribution of boris balinsky to the comparative and ecological embryology of amphibians].	the outstanding embryologist boris ivanovich balinsky (1905-1997) worked in the soviet union up to 1941 and in south africa since 1949. his experimental studies fulfilled during the soviet period of his scientific career mainly on the embryos of the caudate amphibians are widely known. after moving to africa (johannesburg), he continued the research of amphibian development, with using those possibilities, which were offered by the diverse fauna of local anura. other embryologists started comple ...	2015	25720271
ferritin h subunit gene is specifically expressed in melanophore precursor-derived white pigment cells in which reflecting platelets are formed from stage ii melanosomes in the periodic albino mutant of xenopus laevis.	"white pigment cells" are derived from melanophore precursors and contain both melanophore-specific and iridophore-specific pigment organelles. whereas melanophores differentiate in the wild type regenerating tail, white pigment cells appear in the regenerating tail in the periodic albino mutant (a(p)/a(p)) of xenopus laevis. the localization and density of white pigment cells in the mutant regenerating tail are similar to those of melanophores in the wild type regenerating tail. here, white pig ...	2015	25715760
histone titration against the genome sets the dna-to-cytoplasm threshold for the xenopus midblastula transition.	during early development, animal embryos depend on maternally deposited rna until zygotic genes become transcriptionally active. before this maternal-to-zygotic transition, many species execute rapid and synchronous cell divisions without growth phases or cell cycle checkpoints. the coordinated onset of transcription, cell cycle lengthening, and cell cycle checkpoints comprise the midblastula transition (mbt). a long-standing model in the frog, xenopus laevis, posits that mbt timing is controlle ...	2015	25713373
histone h2a and h4 n-terminal tails are positioned by the mep50 wd repeat protein for efficient methylation by the prmt5 arginine methyltransferase.	the protein arginine methyltransferase prmt5 is complexed with the wd repeat protein mep50 (also known as wdr77 or androgen coactivator p44) in vertebrates in a tetramer of heterodimers. mep50 is hypothesized to be required for protein substrate recruitment to the catalytic domain of prmt5. here we demonstrate that the cross-dimer mep50 is paired with its cognate prmt5 molecule to promote histone methylation. we employed qualitative methylation assays and a novel ultrasensitive continuous assay ...	2015	25713080
molecular mechanism of chrdl1-mediated x-linked megalocornea in humans and in xenopus model.	chordin-like 1 (chrdl1) mutations cause non-syndromic x-linked megalocornea (xmc) characterized by enlarged anterior eye segments. mosaic corneal degeneration, presenile cataract and secondary glaucoma are associated with xmc. beside that chrdl1 encodes ventroptin, a secreted bone morphogenetic protein (bmp) antagonist, the molecular mechanism of xmc is not well understood yet. in a family with broad phenotypic variability of xmc, we identified the novel chrdl1 frameshift mutation c.807_808deltc ...	2015	25712132
valproate-induced neurodevelopmental deficits in xenopus laevis tadpoles.	autism spectrum disorder (asd) is increasingly thought to result from low-level deficits in synaptic development and neural circuit formation that cascade into more complex cognitive symptoms. however, the link between synaptic dysfunction and behavior is not well understood. by comparing the effects of abnormal circuit formation and behavioral outcomes across different species, it should be possible to pinpoint the conserved fundamental processes that result in disease. here we use a novel mode ...	2015	25698756
mismatch repair-dependent metabolism of o6-methylguanine-containing dna in xenopus laevis egg extracts.	the cytotoxicity of sn1-type alkylating agents such as n-methyl-n'-nitrosourea (mnu), n-methyl-n'-nitro-n-nitrosoguanidine (mnng), or the cancer chemotherapeutics temozolomide, dacarbazine and streptozotocin has been ascribed to the persistence of o(6)-methylguanine ((me)g) in genomic dna. one hypothesis posits that (me)g toxicity is caused by futile attempts of the mismatch repair (mmr) system to process (me)g/c or (me)g/t mispairs arising during replication, while an alternative proposal sugge ...	2015	25697728
monitoring of rhodopsin trafficking and mistrafficking in live photoreceptors.	outer segment (os) directed trafficking is required for accomplishing the extremely high concentration of rhodopsin and explicitly high photon sensitivity of rod photoreceptor cells. aberrant targeting of rhodopsin often leads to blinding disorders, due to various mechanisms causing rhodopsin mislocalization. until recently, it has been challenging to monitor the dynamics of rhodopsin biogenesis and trafficking. here, we describe a new method to visualize rhodopsin trafficking in living and unfi ...	2015	25697531
patterns of hypothalamic regionalization in amphibians and reptiles: common traits revealed by a genoarchitectonic approach.	most studies in mammals and birds have demonstrated common patterns of hypothalamic development highlighted by the combination of developmental regulatory genes (genoarchitecture), supporting the notion of the hypothalamus as a component of the secondary prosencephalon, topologically rostral to the diencephalon. in our comparative analysis we have summarized the data on the expression patterns of different transcription factors and neuroactive substances, used as anatomical markers, in the devel ...	2015	25691860
one-pot refolding of core histones from bacterial inclusion bodies allows rapid reconstitution of histone octamer.	we report an optimized method to purify and reconstitute histone octamer, which utilizes high expression of histones in inclusion bodies but eliminates the time consuming steps of individual histone purification. in the newly modified protocol, xenopus laevis h2a, h2b, h3, and h4 are expressed individually into inclusion bodies of bacteria, which are subsequently mixed together and denatured in 8m guanidine hydrochloride. histones are refolded and reconstituted into soluble octamer by dialysis a ...	2015	25687285
a functional correlate of severity in alternating hemiplegia of childhood.	mutations in atp1a3, the gene that encodes the α3 subunit of the na(+)/k(+) atpase, are the primary cause of alternating hemiplegia of childhood (ahc). correlations between different mutations and ahc severity were recently reported, with e815k identified in severe and d801n and g947r in milder cases. this study aims to explore the molecular pathological mechanisms in ahc and to identify functional correlates for mutations associated with different levels of disease severity.	2015	25681536
development of a new approach for targeted gene editing in primordial germ cells using talens in xenopus.	a gene of interest can be efficiently modified using transcription activator-like effector nucleases (talens) (christian et al., 2010;li et al., 2011). however, if a target gene is essential for development, growth and fertility, use of talens with high mutagenic activity in f0 frogs could result in developmental disorders or sterility, which would reduce the number of f1 progeny and make f1 phenotypical analysis difficult. we used the 3' untranslated region of deadsouth gene (ds-3') of xenopus ...	2015	25661867
histochemical analyses of biliary development during metamorphosis of xenopus laevis tadpoles.	in mammalian liver development, intrahepatic biliary morphogenesis takes place in periportal, but not in pericentral, regions. liver progenitor cells transiently form epithelial plate structures and then intrahepatic bile ducts around the portal veins under the influence of the mesenchyme. the present study was undertaken to histochemically examine normal biliary development and its dependence on the action of the thyroid hormone triiodothyronine (t3) in xenopus laevis tadpoles. in these tadpole ...	2015	25660701
microtubule-associated protein tau promotes neuronal class ii β-tubulin microtubule formation and axon elongation in embryonic xenopus laevis.	compared with its roles in neurodegeneration, much less is known about microtubule-associated protein tau's normal functions in vivo, especially during development. the external development and ease of manipulating gene expression of xenopus laevis embryos make them especially useful for studying gene function during early development. to study tau's functions in axon outgrowth, we characterized the most prominent tau isoforms of xenopus embryos and manipulated their expression. none of these fo ...	2015	25656701
cnrip1 is a regulator of eye and neural development in xenopus laevis.	cannabinoid receptor interacting protein 1 (cnrip1), which has been originally identified as the binding partner of cannabinoid receptor 1 (cnr1), is evolutionarily conserved throughout vertebrates, but its physiological function has been unknown. here, we identify a developmental role of cnrip1 using xenopus laevis embryos. during early embryogenesis, expression of xenopus laevis cnrip1 is highly restricted to the animal region of gastrulae where neural and eye induction occur, and afterward it ...	2015	25652037
understanding early organogenesis using a simplified in situ hybridization protocol in xenopus.	organogenesis is the study of how organs are specified and then acquire their specific shape and functions during development. the xenopuslaevis embryo is very useful for studying organogenesis because their large size makes them very suitable for identifying organs at the earliest steps in organogenesis. at this time, the primary method used for identifying a specific organ or primordium is whole mount in situ hybridization with labeled antisense rna probes specific to a gene that is expressed ...	2015	25651461
semicircular canal-dependent developmental tuning of translational vestibulo-ocular reflexes in xenopus laevis.	gaze stabilization during head/body movements is achieved to a large extent by vestibular-evoked compensatory eye movements. these reflexes derive from semicircular canal and otolith organs and depend on the transformation of the respective sensory signals into extraocular motor commands. to elicit directionally and dynamically appropriate compensatory eye movements, extraocular motoneurons require spatiotemporally specific inputs from semicircular canals and regions of the utricular epithelium ...	2015	25266079
evolutionarily conserved role for soxc genes in neural crest specification and neuronal differentiation.	members of the sox family of transcription factors play a variety of critical developmental roles in both vertebrates and invertebrates. whereas soxbs and soxes are involved in neural and neural crest development, respectively, far less is known about members of the soxc subfamily. to address this from an evolutionary perspective, we compare expression and function of soxc genes in neural crest cells and their derivatives in lamprey (petromyzon marinus), a basal vertebrate, to frog (xenopus laev ...	2015	25286121
analysis of nuclear reprogramming following nuclear transfer to xenopus oocyte.	germinal vesicle of stage v-vi xenopus laevis oocytes (at the prophase i stage of meiosis) can be used to transplant mammalian nuclei. in this type of interspecies nuclear transfer no cell division occurs and no new cell types are generated. however, the transplanted nuclei undergo extensive transcriptional reprogramming. here, it is first explained how to carry out transplantation of multiple mammalian cell nuclei to xenopus oocytes. it is then described how to perform rt-qpcr, western blot, ch ...	2015	25287339
glycine transporters glyt1 and glyt2 are differentially modulated by glycogen synthase kinase 3β.	inhibitory glycinergic neurotransmission is terminated by the specific glycine transporters glyt1 and glyt2 which actively reuptake glycine from the synaptic cleft. glyt1 is associated with both glycinergic and glutamatergic pathways, and is the main regulator of the glycine levels in the synapses. glyt2 is the main supplier of glycine for vesicle refilling, a process that is vital to preserve the quantal glycine content in synaptic vesicles. therefore, to control glycinergic neurotransmission e ...	2015	25301276
cd44 functions in wnt signaling by regulating lrp6 localization and activation.	wnt reception at the membrane is complex and not fully understood. cd44 is a major wnt target gene in the intestine and is essential for wnt-induced tumor progression in colorectal cancer. here we show that cd44 acts as a positive regulator of the wnt receptor complex. downregulation of cd44 expression decreases, whereas cd44 overexpression increases wnt activity in a concentration-dependent manner. epistasis experiments place cd44 function at the level of the wnt receptor lrp6. mechanistically, ...	2015	25301071
comparative genomic and expression analysis of the adenosine signaling pathway members in xenopus.	adenosine is an endogenous molecule that regulates many physiological processes via the activation of four specific g-protein-coupled adora receptors. extracellular adenosine may originate either from the hydrolysis of released atp by the ectonucleotidases or from cellular exit via the equilibrative nucleoside transporters (slc29a). adenosine extracellular concentration is also regulated by its successive hydrolysis into uric acid by membrane-bound enzymes or by cell influx via the concentrative ...	2015	25319637
xenbase, the xenopus model organism database; new virtualized system, data types and genomes.	xenbase (http://www.xenbase.org), the xenopus frog model organism database, integrates a wide variety of data from this biomedical model genus. two closely related species are represented: the allotetraploid xenopus laevis that is widely used for microinjection and tissue explant-based protocols, and the diploid xenopus tropicalis which is used for genetics and gene targeting. the two species are extremely similar and protocols, reagents and results from each species are often interchangeable. x ...	2015	25313157
different solvent fractions of acanthopanax senticosus harms exert antioxidant and anti-inflammatory activities and inhibit the human kv1.3 channel.	the potential antioxidant and anti-inflammatory activities of acanthopanax senticosus harms were evaluated and its effect on the human kv1.3 potassium channel was detected. the ethyl acetate fraction possessed the highest phenolic (289.19±7.43 mg tannic acid equivalents/g) and flavonoid (10.80±0.67 mg quercetin equivalents/g) contents and exhibited stronger antioxidant effects than other fractions in most of the antioxidant assays. on the other hand, the dichloromethane (ch(2)cl(2)) fraction sho ...	2015	25340513
histone methyltransferase dot1l plays a role in postembryonic development in xenopus tropicalis.	histone methylations have been implicated to play important roles in diverse cellular processes. of particular interest is the methylation of histone h3k79, which is catalyzed by an evolutionarily conserved methyltransferase, disruptor of telomeric silencing (dot1)-like (dot1l). to investigate the role of dot1l during vertebrate development, we have generated a dot1l-specific transcription activator-like effector nuclease (talen) nuclease to knockdown endogenous dot1l in xenopus tropicalis, a di ...	2015	25366346
flow sensing in developing xenopus laevis is disrupted by visual cues and ototoxin exposure.	we explored how lateral line cues interact with visual cues to mediate flow sensing behaviors in the nocturnal developing frog, xenopus laevis, by exposing animals to current flows under different lighting conditions and after exposure to the ototoxin gentamicin. under dark conditions, xenopus tadpoles move downstream at the onset of current flow, then turn, and orient toward the direction of the flow with high accuracy. postmetamorphic froglets also exhibit positive rheotaxis but with less accu ...	2015	25380559
phosphatidylinositol 4,5-bisphosphate degradation inhibits the na+/bicarbonate cotransporter nbce1-b and -c variants expressed in xenopus oocytes.	we previously reported that the phospholipid phosphatidylinositol 4,5-bisphosphate (pip2 ) directly stimulates heterologously expressed electrogenic na(+)/bicarbonate cotransporter nbce1-a in an excised macropatch from the xenopus oocyte, and indirectly stimulates nbce1-b and -c in the intact oocyte primarily through inositol 1,4,5-trisphosphate/ca(2+). in the current study, we expand on a previous observation that pip2 may also directly stimulate nbce1 in the intact oocyte. in this study on ooc ...	2015	25398525
hcn2 channels: a permanent open state and conductance changes.	hyperpolarization-activated cyclic nucleotide-gated (hcn) channels in the membranes of heart and brain cells can conduct na(+) and k(+) ions and activate between -30 and -120 mv. we express the α subunit of hcn2 channels in xenopus laevis oocytes and are confronted with two unexpected problems. first, we observe a rise in membrane conductance at resting potential proportional to the amount of expression. on activation to hyperpolarizing potentials, the instantaneous conductance rises in proporti ...	2015	25391723
system l amino acid transporter lat1 accumulates o-(2-fluoroethyl)-l-tyrosine (fet).	o-(2-fluoroethyl)-l-tyrosine (fet) labeled with fluorine-18 is an important and specific tracer for diagnostics of glioblastoma via positron emission tomography (pet). however, the mechanism of its quite specific accumulation in tumor tissue has not been understood so far. in this work we demonstrate that [(3)h]l-tyrosine is primarily transported by the system l transporter lat1 in human ln229 glioblastoma cells. fet reduced tyrosine transport, suggesting that it shares the same uptake pathway. ...	2015	25385314
protocadherin-9 involvement in retinal development in xenopus laevis.	biological roles of most protocadherins (pcdhs) are a largely unsolved problem. therefore, we cloned cdna for xenopus laevis protocadherin-9 and characterized its properties to elucidate the role. the deduced amino acid sequence was highly homologous to those of mammalian protocadherin-9 s. x. laevis protocadherin-9 expressed from the cdna in l cells showed basic properties similar to those of mammalian pcdhs. expression of x. laevis protocadherin-9 was first detected in stage-31 embryos and inc ...	2015	25414271
mutations in the voltage-gated potassium channel gene kcnh1 cause temple-baraitser syndrome and epilepsy.	temple-baraitser syndrome (tbs) is a multisystem developmental disorder characterized by intellectual disability, epilepsy, and hypoplasia or aplasia of the nails of the thumb and great toe. here we report damaging de novo mutations in kcnh1 (encoding a protein called ether à go-go, eag1 or kv10.1), a voltage-gated potassium channel that is predominantly expressed in the central nervous system (cns), in six individuals with tbs. characterization of the mutant channels in both xenopus laevis oocy ...	2015	25420144
a novel method for inducing nerve growth via modulation of host resting potential: gap junction-mediated and serotonergic signaling mechanisms.	a major goal of regenerative medicine is to restore the function of damaged or missing organs through the implantation of bioengineered or donor-derived components. it is necessary to understand the signals and cues necessary for implanted structures to innervate the host, as organs devoid of neural connections provide little benefit to the patient. while developmental studies have identified neuronal pathfinding molecules required for proper patterning during embryogenesis, strategies to initia ...	2015	25449797
a method for using direct injection of plasmid dna to study cis-regulatory element activity in f0 xenopus embryos and tadpoles.	the ability to express exogenous reporter genes in intact, externally developing embryos, such as xenopus, is a powerful tool for characterizing the activity of cis-regulatory gene elements during development. although methods exist for generating transgenic xenopus lines, more simplified methods for use with f0 animals would significantly speed the characterization of these elements. we discovered that injecting 2-cell stage embryos with a plasmid bearing a ϕc31 integrase-targeted attb element ...	2015	25448690
cellular characterization of thrombocytes in xenopus laevis with specific monoclonal antibodies.	platelets are produced from megakaryocytes (mks) in the bone marrow. in contrast, most nonmammalian vertebrates have nucleated and spindle-shaped thrombocytes instead of platelets in their circulatory systems, and the presence of mks as thrombocyte progenitors has not been verified. in developing a new animal model in adult african clawed frog (xenopus laevis), we needed to distinguish nucleated thrombocytes and their progenitors from other blood cells, because the cellular morphology of activat ...	2015	25448492
changes in gastric sodium-iodide symporter (nis) activity are associated with differences in thyroid gland sensitivity to perchlorate during metamorphosis.	we investigated stage-dependent changes in sensitivity of the thyroid gland to perchlorate during development of african clawed frog tadpoles (xenopus laevis) in relation to non-thyroidal iodide transporting tissues. perchlorate-induced increases in thyroid follicle cell size and colloid depletion were blunted when exposures began at nieuwkoop-faber (nf) stage 55 compared to when exposures began at nf stages 49 or 1-10. to determine if the development of other iodide transporting tissues may con ...	2015	25448256
biological and biochemical properties of two xenopus laevis n-acetylgalactosaminyltransferases with contrasting roles in embryogenesis.	the biosynthesis of mucin-type o-linked glycans in animals is initiated by members of the large family of polypeptide n-acetylgalactosaminyltransferases (galnac-ts), which play important roles in embryogenesis, organogenesis, adult tissue homeostasis and carcinogenesis. until now, the mammalian forms of these enzymes have been the best characterized. however, two n-acetylgalactosaminyltransferases (xgalnac-t6 and xgalnac-t16) from the african clawed frog (xenopus laevis), which are most homologo ...	2015	25447273
a gene expression map of the larval xenopus laevis head reveals developmental changes underlying the evolution of new skeletal elements.	the morphology of the vertebrate head skeleton is highly plastic, with the number, size, shape, and position of its components varying dramatically between groups. while this evolutionary flexibility has been key to vertebrate success, its developmental and genetic bases are poorly understood. the larval head skeleton of the frog xenopus laevis possesses a unique combination of ancestral tetrapod features and anuran-specific novelties. we built a detailed gene expression map of the head mesenchy ...	2015	25446275
xenopus laevis fgf receptor substrate 3 (xfrs3) is important for eye development and mediates pax6 expression in lens placode through its shp2-binding sites.	members of the fibroblast growth factor (fgf) family play important roles during various developmental processes including eye development. frs (fgf receptor substrate) proteins bind to fgfr and serve as adapters for coordinated assembly of multi-protein complexes involved in ras/mapk and pi3 kinase/akt pathways. here, we identified xenopus laevis frs3 (xfrs3), a homolog of vertebrate frs3, and investigated its roles during embryogenesis. xfrs3 is expressed maternally and zygotically with specif ...	2015	25446028
transcriptional changes in african clawed frogs (xenopus laevis) exposed to 17α-ethynylestradiol during early development.	although the past two decades have witnessed a significant increase in the number of studies investigating effects of estrogenic chemicals on amphibians, to date little is known about specific molecular interactions of estrogens with the hypothalamus-pituitary-gonadal-hepatic axis in developing amphibians. here, tissue-specific functional sets of genes, derived previously from studies of fishes exposed to endocrine active chemicals, were evaluated in xenopus laevis exposed to 17α-ethynylestradio ...	2015	25427717
ntpdase2 and the p2y1 receptor are not required for mammalian eye formation.	eye formation in vertebrates is controlled by a conserved pattern of molecular networks. homeobox transcription factors are crucially involved in the establishment and maintenance of the retina. a previous study of massé et al. (nature, 449: 1058-62, 2007) using morpholino knockdown identified the ectonucleotidase ntpdase2 and the p2y1 receptor as essential elements for eye formation in embryos of the clawed frog xenopus laevis. in order to investigate whether a similarly essential mechanism wou ...	2015	25504514
kcnip1 a ca²⁺-dependent transcriptional repressor regulates the size of the neural plate in xenopus.	in amphibian embryos, our previous work has demonstrated that calcium transients occurring in the dorsal ectoderm at the onset of gastrulation are necessary and sufficient to engage the ectodermal cells into a neural fate by inducing neural specific genes. some of these genes are direct targets of calcium. here we search for a direct transcriptional mechanism by which calcium signals are acting. the only known mechanism responsible for a direct action of calcium on gene transcription involves an ...	2015	25499267
the small heat shock protein, hsp30, is associated with aggresome-like inclusion bodies in proteasomal inhibitor-, arsenite-, and cadmium-treated xenopus kidney cells.	in the present study, treatment of xenopus laevis a6 kidney epithelial cells with the proteasomal inhibitor, mg132, or the environmental toxicants, sodium arsenite or cadmium chloride, induced the accumulation of the small heat shock protein, hsp30, in total and in both soluble and insoluble protein fractions. immunocytochemical analysis revealed the presence of relatively large hsp30 structures primarily in the perinuclear region of the cytoplasm. all three of the stressors promoted the formati ...	2015	26260897
fluorescent ratiometric ph indicator sypher2: applications in neuroscience and regenerative biology.	sypher is a genetically encoded fluorescent ph-indicator with a ratiometric readout, suitable for measuring fast intracellular ph shifts. however, the relatively low brightness of the indicator limits its use.	2015	26259819
brain-derived neurotrophic factor (bdnf) expression in normal and regenerating olfactory epithelium of xenopus laevis.	olfactory epithelium has the capability to continuously regenerate olfactory receptor neurons throughout life. adult neurogenesis results from proliferation and differentiation of neural stem cells, and consequently, olfactory neuroepithelium offers an excellent opportunity to study neural regeneration and the factors involved in the maintenance and regeneration of all their cell types. we analyzed the expression of bdnf in the olfactory system under normal physiological conditions as well as du ...	2015	25488259
distinct action of the α-glucosidase inhibitor miglitol on sglt3, enteroendocrine cells, and glp1 secretion.	oral ingestion of carbohydrate triggers glucagon-like peptide 1 (glp1) secretion, but the molecular mechanism remains elusive. by measuring glp1 concentrations in murine portal vein, we found that the atp-sensitive k(+) (katp) channel is not essential for glucose-induced glp1 secretion from enteroendocrine l cells, while the sodium-glucose co-transporter 1 (sglt1) is required, at least in the early phase (5 min) of secretion. by contrast, co-administration of the α-glucosidase inhibitor (α-gi) m ...	2015	25486965
nuclear size scaling during xenopus early development contributes to midblastula transition timing.	early xenopus laevis embryogenesis is a robust system for investigating mechanisms of developmental timing. after a series of rapid cell divisions with concomitant reductions in cell size, the first major developmental transition is the midblastula transition (mbt), when zygotic transcription begins and cell cycles elongate. whereas the maintenance of a constant nuclear-to-cytoplasmic (n/c) volume ratio is a conserved cellular property, it has long been recognized that the n/c volume ratio chang ...	2015	25484296
aminolevulinate synthase 2 mediates erythrocyte differentiation by regulating larval globin expression during xenopus primary hematopoiesis.	hemoglobin synthesis by erythrocytes continues throughout a vertebrate's lifetime. the mechanism of mammalian heme synthesis has been studied for many years; aminolevulinate synthase 2 (alas2), a heme synthetase, is associated with x-linked dominant protoporphyria in humans. amphibian and mammalian blood cells differ, but little is known about amphibian embryonic hemoglobin synthesis. we investigated the function of the xenopus alas2 gene (xalas2) in primitive amphibian erythrocytes and found th ...	2015	25482442