Publications

labeling strategy and signal broadening mechanism of protein nmr spectroscopy in xenopus laevis oocytes.	we used xenopus laevis oocytes, a paradigm for a variety of biological studies, as a eukaryotic model system for in-cell protein nmr spectroscopy. the small globular protein gb1 was one of the first studied in xenopus oocytes, but there have been few reports since then of high-resolution spectra in oocytes. the scarcity of data is at least partly due to the lack of good labeling strategies and the paucity of information on resonance broadening mechanisms. here, we systematically evaluate isotope ...	2015	25965532
conformational rearrangements in the transmembrane domain of cnga1 channels revealed by single-molecule force spectroscopy.	cyclic nucleotide-gated (cng) channels are activated by binding of cyclic nucleotides. although structural studies have identified the channel pore and selectivity filter, conformation changes associated with gating remain poorly understood. here we combine single-molecule force spectroscopy (smfs) with mutagenesis, bioinformatics and electrophysiology to study conformational changes associated with gating. by expressing functional channels with smfs fingerprints in xenopus laevis oocytes, we we ...	2015	25963832
positive modulation of synaptic and extrasynaptic gabaa receptors by an antagonist of the high affinity benzodiazepine binding site.	gabaa receptors are the major inhibitory neurotransmitter receptors in the brain and are the target for many clinically important drugs such as the benzodiazepines. benzodiazepines act at the high-affinity binding site at the α+/γ- subunit interface. previously, an additional low affinity binding site for diazepam located in the transmembrane (tm) domain has been described. the compound sjm-3 was recently identified in a prospective screening of ligands for the benzodiazepine binding site and in ...	2015	25963418
xenopus laevis oocyte maturation is affected by metal chlorides.	few studies have been conducted using xenopus laevis germ cells as oocytes, though these cells offer many advantages allowing both electrophysiological studies and morphological examination. our aim was to investigate the effects of metal (cadmium, lead, cobalt and zinc) exposures using cell biology approaches. first, cell survival was evaluated with both phenotypical and electrophysiological approaches. secondly, the effect of metals on oocyte maturation was assessed with morphological observat ...	2015	25957907
building the microtubule cytoskeleton piece by piece.	the microtubule (mt) cytoskeleton gives cells their shape, organizes the cellular interior, and segregates chromosomes. these functions rely on the precise arrangement of mts, which is achieved by the coordinated action of mt-associated proteins (maps). we highlight the first and most important examples of how different map activities are combined in vitro to create an ensemble function that exceeds the simple addition of their individual activities, and how the xenopus laevis egg extract system ...	2015	25957410
in vitro, ex vivo, and in vivo determination of thyroid hormone modulating activity of benzothiazoles.	as in vitro assays are increasingly used to screen chemicals for their potential to produce endocrine disrupting adverse effects, it is important to understand their predictive capacity. the potential for a set of 6 benzothiazoles to affect endpoints related to thyroid hormone synthesis inhibition were assessed using in vitro, ex vivo, and in vivo assays. inhibition of thyroid peroxidase (tpo) derived from pig thyroid glands was determined for benzothiazole (btz), 2-mercaptobenzothiazole (mbt), ...	2015	25953703
subchronic and chronic developmental effects of copper oxide (cuo) nanoparticles on xenopus laevis.	metal oxide nanoparticles, such as copper oxide (cuo), are mass produced for use in a variety of products like coatings and ceramics. acute exposure to cuo nanoparticles has caused toxicity to many aquatic organisms, yet there is no information on the effect of prolonged cuo nanomaterial exposures. this study examined effects of chronic exposure to cuo nanoparticles on xenopus laevis growth and development. experiments included a 14 d subchronic exposure and a 47 d chronic exposure throughout me ...	2015	25950410
mgcracgap restricts active rhoa at the cytokinetic furrow and both rhoa and rac1 at cell-cell junctions in epithelial cells.	localized activation of rho gtpases is essential for multiple cellular functions, including cytokinesis and formation and maintenance of cell-cell junctions. although mgcracgap (mgc) is required for spatially confined rhoa-gtp at the equatorial cortex of dividing cells, both the target specificity of mgc's gap activity and the involvement of phosphorylation of mgc at ser-386 are controversial. in addition, mgc's function at cell-cell junctions remains unclear. here, using gastrula-stage xenopus ...	2015	25947135
structural insights into thyroid hormone transport mechanisms of the l-type amino acid transporter 2.	thyroid hormones (ths) are transported across cell membranes by different transmembrane transporter proteins. in previous studies, we showed marked 3,3'-diiodothyronine (3,3'-t2) but moderate t3 uptake by the l-type amino acid transporter 2 (lat2). we have now studied the structure-function relationships of this transporter and th-like molecules. our lat2 homology model is based on 2 crystal structures of the homologous 12-transmembrane helix transporters arginine/agmatine antiporter and amino a ...	2015	25945809
single-cell mass spectrometry reveals small molecules that affect cell fates in the 16-cell embryo.	spatial and temporal changes in molecular expression are essential to embryonic development, and their characterization is critical to understand mechanisms by which cells acquire different phenotypes. although technological advances have made it possible to quantify expression of large molecules during embryogenesis, little information is available on metabolites, the ultimate indicator of physiological activity of the cell. here, we demonstrate that single-cell capillary electrophoresis-electr ...	2015	25941375
controlled surface topography regulates collective 3d migration by epithelial-mesenchymal composite embryonic tissues.	cells in tissues encounter a range of physical cues as they migrate. probing single cell and collective migratory responses to physically defined three-dimensional (3d) microenvironments and the factors that modulate those responses are critical to understanding how tissue migration is regulated during development, regeneration, and cancer. one key physical factor that regulates cell migration is topography. most studies on surface topography and cell mechanics have been carried out with single ...	2015	25933063
regulation of hbpip2;3, a latex-abundant water transporter, is associated with latex dilution and yield in the rubber tree (hevea brasiliensis muell. arg.).	rubber tree (hevea brasiliensis) latex, the source of natural rubber, is synthesised in the cytoplasm of laticifers. efficient water inflow into laticifers is crucial for latex flow and production since it is the determinant of the total solid content of latex and its fluidity after tapping. as the mature laticifer vessel rings are devoid of plasmodesmata, water exchange between laticifers and surrounding cells is believed to be governed by plasma membrane intrinsic proteins (pips). to identify ...	2015	25927524
quantum dot assisted tracking of the intracellular protein cyclin e in xenopus laevis embryos.	luminescent semiconductor nanocrystals, also known as quantum dots (qd), possess highly desirable optical properties that account for development of a variety of exciting biomedical techniques. these properties include long-term stability, brightness, narrow emission spectra, size tunable properties and resistance to photobleaching. qd have many promising applications in biology and the list is constantly growing. these applications include dna or protein tagging for in vitro assays, deep-tissue ...	2015	25925383
disruption of the rice nitrate transporter osnpf2.2 hinders root-to-shoot nitrate transport and vascular development.	plants have evolved to express some members of the nitrate transporter 1/peptide transporter family (npf) to uptake and transport nitrate. however, little is known of the physiological and functional roles of this family in rice (oryza sativa l.). here, we characterized the vascular specific transporter osnpf2.2. functional analysis using cdna-injected xenopus laevis oocytes revealed that osnpf2.2 is a low-affinity, ph-dependent nitrate transporter. use of a green fluorescent protein tagged osnp ...	2015	25923512
hplc-based activity profiling for herg channel inhibitors in the south african medicinal plant galenia africana.	the human ether-a-go-go-related gene channel is a voltage-activated k(+) channel involved in cardiac action potential. its inhibition can lead to qt prolongation, and eventually to potentially fatal arrhythmia. therefore, it is considered a primary antitarget in safety pharmacology. to assess the risk of human ether-a-go-go-related gene channel inhibition by medicinal plants, 700 extracts from different parts of 142 medicinal plants collected in southern africa were screened on xenopus laevis oo ...	2015	25922911
homeolog-specific targeted mutagenesis in xenopus laevis using talens.	transcription activator-like effector nucleases (talens) have previously been used for targeted genome editing in various organisms including xenopus laevis. however, because of genomic polyploidization, x. laevis usually possess homeologous genes (homeologs) with quite similar sequences that make the analysis of gene function difficult. in the present study, we show methodological examples of targeted gene modification of x. laevis homeologs. the x. laevis cytoglobin gene (cygb) consists of two ...	2015	25920501
developing xenopus embryos recover by compacting and expelling single wall carbon nanotubes.	single wall carbon nanotubes are high aspect ratio nanomaterials being developed for use in materials, technological and biological applications due to their high mechanical stiffness, optical properties and chemical inertness. because of their prevalence, it is inevitable that biological systems will be exposed to nanotubes, yet studies of the effects of nanotubes on developing embryos have been inconclusive and are lacking for single wall carbon nanotubes exposed to the widely studied model or ...	2016	26153061
xenopus lap2β protein knockdown affects location of lamin b and nucleoporins and has effect on assembly of cell nucleus and cell viability.	xenopus lap2β protein is the single isoform expressed in xtc cells. the protein localizes on heterochromatin clusters both at the nuclear envelope and inside a cell nucleus. the majority of xlap2β fraction neither colocalizes with tpx2 protein during interphase nor can be immunoprecipitated with xlap2β antibody. knockdown of the xlap2β protein expression in xtc cells by synthetic sirna and plasmid encoded sirna resulted in nuclear abnormalities including changes in shape of nuclei, abnormal chro ...	2016	26209045
cell cycle synchronization in xenopus egg extracts.	many important discoveries in cell cycle research have been made using cell-free extracts prepared from the eggs of the south african clawed frog xenopus laevis. these extracts efficiently support the key nuclear functions of the eukaryotic cell cycle in vitro under apparently the same controls that exist in vivo. the xenopus cell-free system is therefore uniquely suited to the study of the mechanisms, dynamics and integration of cell cycle regulated processes at a biochemical level. here, we de ...	2016	26254920
identification of genes expressed in the migrating primitive myeloid lineage of xenopus laevis.	during primitive hematopoiesis in xenopus, cebpa and spib expressing myeloid cells emerge from the anterior ventral blood island. primitive myeloid cells migrate throughout the embryo and are critical for immunity, healing, and development. although definitive hematopoiesis has been studied extensively, molecular mechanisms leading to the migration of primitive myelocytes remain poorly understood. we hypothesized these cells have specific extracellular matrix modifying and cell motility gene exp ...	2016	26264370
regulation of growth rate and developmental timing by xenopus thyroid hormone receptor α.	thyroid hormone (th) is critical for vertebrate postembryonic development, a period around birth in mammals when plasma th levels are high. interestingly, th receptors (trs), especially trα, are expressed prior to the synthesis and secretion of zygotic th, suggesting the existence of unliganded tr during development. however, the role of unliganded tr during mammalian development has been difficult to study, in part due to the relatively weak phenotype of tr knockout mice. amphibian metamorphosi ...	2016	26219216
metamorphic remodeling of the olfactory organ of the african clawed frog, xenopus laevis.	the amphibian olfactory system undergoes massive remodeling during metamorphosis. the transition from aquatic olfaction in larvae to semiaquatic or airborne olfaction in adults requires anatomical, cellular, and molecular modifications. these changes are particularly pronounced in pipidae, whose adults have secondarily adapted to an aquatic life style. in the fully aquatic larvae of xenopus laevis, the main olfactory epithelium specialized for sensing water-borne odorous substances lines the pri ...	2016	26294036
phosphorylation at serine 52 and 635 does not alter the transport properties of glucosinolate transporter atgtr1.	little is known about how plants regulate transporters of defense compounds. in a. thaliana, glucosinolates are transported between tissues by npf2.10 (atgtr1) and npf2.11 (atgtr2). mining of the phosphat4.0 database showed two cytosol exposed phosphorylation sites for atgtr1 and one membrane-buried phosphorylation site for atgtr2. in this study, we investigate whether mutation of the two potential regulatory sites of atgtr1 affected transport of glucosinolates in xenopus oocytes. characterizati ...	2016	26340317
proteomics of xenopus development.	modern mass spectrometry-based methods provide an exciting opportunity to characterize protein expression in the developing embryo. we have employed an isotopic labeling technology to quantify the expression dynamics of nearly 6000 proteins across six stages of development in xenopus laevis from the single stage zygote through the mid-blastula transition and the onset of organogenesis. approximately 40% of the proteins show significant changes in expression across the development stages. the exp ...	2016	26396253
complicated behavior of g-quadruplexes and evaluating g-quadruplexes' ligands in various systems mimicking cellular circumstance.	environments surrounding g-rich sequences remarkably affect the conformations of these structures. a proper evaluation system mimicking the crowded environment in a cell with macromolecules should be developed to perform structural and functional studies on g-quadruplexes. in this study, the topology and stability of a g-quadruplex formed by human telomeric repeat sequences were investigated in a macromolecule-crowded environment created by polyethylene glycol 200 (peg200), tumor cell extract, a ...	2016	28955851
nearly 1000 protein identifications from 50 ng of xenopus laevis zygote homogenate using online sample preparation on a strong cation exchange monolith based microreactor coupled with capillary zone electrophoresis.	a sulfonate-silica hybrid strong cation exchange monolith microreactor was synthesized and coupled to a linear polyacrylamide coated capillary for online sample preparation and capillary zone electrophoresis-tandem mass spectrometry (cze-ms/ms) bottom-up proteomic analysis. the protein sample was loaded onto the microreactor in an acidic buffer. after online reduction, alkylation, and digestion with trypsin, the digests were eluted with 200 mm ammonium bicarbonate at ph 8.2 for cze-ms/ms analysi ...	2016	26670623
quantitative analysis of filament branch orientation in listeria actin comet tails.	several bacterial and viral pathogens hijack the host actin cytoskeleton machinery to facilitate spread and infection. in particular, listeria uses arp2/3-mediated actin filament nucleation at the bacterial surface to generate a branched network that will help propel the bacteria. however, the mechanism of force generation remains elusive due to the lack of high-resolution three-dimensional structural data on the spatial organization of the actin mother and daughter (i.e., branch) filaments with ...	2016	26497103
effects of dietary exposure of polycyclic musk hhcb on the metamorphosis of xenopus laevis.	the compound 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta-[γ]-2-benzopyrane (hhcb; galaxolide, chemical abstracts service number 1222-05-5) is a synthetic musk used extensively as a fragrance in many consumer products and classified as an emerging pollutant. the ecotoxicological information available for hhcb addresses exposure via water, but this compound is frequently adsorbed into particulate matter. the goal of the present study was to assess the effects of dietary exposure to seve ...	2016	26472276
catalytic activity of human carbonic anhydrase isoform ix is displayed both extra- and intracellularly.	most carbonic anhydrases catalyse the reversible conversion of carbon dioxide to protons and bicarbonate, either as soluble cytosolic enzymes, in or at intracellular organelles, or at the extracellular face of the cell membrane as membrane-anchored proteins. carbonic anhydrase isoform ix (ca ix), a membrane-bound enzyme with catalytic activity at the extracellular membrane surface, has come to prominence in recent years because of its association with hypoxic tissue, particularly tumours, often ...	2016	26470855
bumetanide derivatives aqb007 and aqb011 selectively block the aquaporin-1 ion channel conductance and slow cancer cell migration.	aquaporins (aqps) in the major intrinsic family of proteins mediate fluxes of water and other small solutes across cell membranes. aqp1 is a water channel, and under permissive conditions, a nonselective cation channel gated by cgmp. in addition to mediating fluid transport, aqp1 expression facilitates rapid cell migration in cell types including colon cancers and glioblastoma. work here defines new pharmacological derivatives of bumetanide that selectively inhibit the ion channel, but not the w ...	2016	26467039
phosphorylation of rs1 (rsc1a1) steers inhibition of different exocytotic pathways for glucose transporter sglt1 and nucleoside transporter cnt1, and an rs1-derived peptide inhibits glucose absorption.	cellular uptake adapts rapidly to physiologic demands by changing transporter abundance in the plasma membrane. the human gene rsc1a1 codes for a 67-kda protein named rs1 that has been shown to induce downregulation of the sodium-d-glucose cotransporter 1 (sglt1) and of the concentrative nucleoside transporter 1 (cnt1) in the plasma membrane by blocking exocytosis at the golgi. injecting rs1 fragments into xenopus laevis oocytes expressing sglt1 or cnt1 and measuring the expressed uptake of α-me ...	2016	26464324
a curcumin analog, go-y078, effectively inhibits angiogenesis through actin disorganization.	the inhibition of angiogenesis is a theoretically ideal chemotherapy for cancer, but there remains room for improvement. most inhibitors of angiogenesis approved to date target vascular endothelial growth factors (vegfs); however, vegfs are only one of the many classes of participant in tumor angiogenesis. because tumor angiogenesis is orchestrated by many components, including growth factors, signal transducers, and effectors, its regulation exhibits redundancy. curcumin can associate with many ...	2016	26459768
monitoring smad activity in vivo using the xenopus model system.	the embryo of the african clawed frog xenopus laevis plays a central role in the field of cell and developmental biology. one of the strengths of xenopus as model system lies in the high degree of conservation between amphibians and mammals in the molecular mechanisms controlling tissue patterning and differentiation. as such, many signaling cascades were first investigated in frog embryos and then confirmed in mouse and/or human cells. the tgf-β signaling cascade greatly benefited from this mod ...	2016	26520129
the prototoxin lypd6b modulates heteromeric α3β4-containing nicotinic acetylcholine receptors, but not α7 homomers.	prototoxins are a diverse family of membrane-tethered molecules expressed in the nervous system that modulate nicotinic cholinergic signaling, but their functions and specificity have yet to be completely explored. we tested the selectivity and efficacy of leukocyte antigen, plaur (plasminogen activator, urokinase receptor) domain-containing (lypd)-6b on α3β4-, α3α5β4-, and α7-containing nicotinic acetylcholine receptors (nachrs). to constrain stoichiometry, fusion proteins encoding concatemers ...	2016	26586467
effect of n-glycosylation on the transport activity of the peptide transporter pept1.	the intestinal peptide transporter pept1 provides bulk quantities of amino acids to epithelial cells. pept1 is a high-capacity and low-affinity solute carrier of the slc15 family found in apical membranes of enterocytes in small intestine and distal colon. surprisingly, murine pept1 (mpept1) has an apparent molecular mass of ∼95 kda in the small intestine but ∼105 kda in the large intestine. here we describe studies on mpept1 protein glycosylation and how glycans affect transport function. putat ...	2016	26585416
sex differences and endocrine regulation of auditory-evoked, neural responses in african clawed frogs (xenopus).	mating depends on the accurate detection of signals that convey species identity and reproductive state. in african clawed frogs, xenopus, this information is conveyed by vocal signals that differ in temporal patterns and spectral features between sexes and across species. we characterized spectral sensitivity using auditory-evoked potentials (aeps), commonly known as the auditory brainstem response, in males and females of four xenopus species. in female x. amieti, x. petersii, and x. laevis, p ...	2016	26572136
identification of an inhibitory alcohol binding site in gabaa ρ1 receptors.	alcohols inhibit γ-aminobutyric acid type a ρ1 receptor function. after introducing mutations in several positions of the second transmembrane helix in ρ1, we studied the effects of ethanol and hexanol on gaba responses using two-electrode voltage clamp electrophysiology in xenopus laevis oocytes. the 6' mutations produced the following effects on ethanol and hexanol responses: small increase or no change (t6'm), increased inhibition (t6'v), and small potentiation (t6'y and t6'f). the 5' mutatio ...	2016	26571107
quantification of x. laevis vitellogenin by liquid chromatography tandem mass spectrometry.	over the last several decades, there has been an increase in public awareness and regulatory activity in regard to the presence of emerging contaminants in the environment that may have the potential to interact with the endocrine system of exposed wildlife. alterations in vitellogenin (vtg), a high density yolk precursor protein, can indicate endocrine activity in oviparous species, including many fish and amphibians. while various methodologies and experiments have been performed to characteri ...	2016	26562177
distinctive effects of nicotinic receptor intracellular-loop mutations associated with nocturnal frontal lobe epilepsy.	previously characterized nicotinic acetylcholine receptor (nachr) autosomal dominant nocturnal frontal lobe epilepsy (adnfle)-associated mutations are found in α2, α4 and β2 subunit transmembrane (tm) domains. they predominantly increase ach potency and, for β2-subunit mutants, increase macroscopic currents. two recently-identified mutations, α4(r336h) and β2(v337g), located in the intracellular cytoplasmic loop (c2) have been associated with non-familial nfle. effects of these mutations on α4β2 ...	2016	26561946
alternative splice variant of the thiazide-sensitive nacl cotransporter: a novel player in renal salt handling.	the thiazide-sensitive nacl cotransporter (ncc) is an important pharmacological target in the treatment of hypertension. the human slc12a3 gene, encoding ncc, gives rise to three isoforms. only the third isoform has been extensively investigated. the aim of the present study was, therefore, to establish the abundance and localization of the almost identical isoforms 1 and 2 (ncc1/2) in the human kidney and to determine their functional properties and regulation in physiological conditions. immun ...	2016	26561651
identification of micrornas and microrna targets in xenopus gastrulae: the role of mir-26 in the regulation of smad1.	micrornas (mirnas) are known to play diverse roles in the regulation of vertebrate development. to investigate mirna-target mrna relationships in embryonic development, we have carried out small-rna sequencing to identify mirnas expressed in the early gastrula of xenopus laevis. we identify a total of 180 mirnas, and we have identified the locations of the mirna precursor sequences in the x. laevis genome. of these mirnas, 141 represent mirs previously identified in xenopus tropicalis. alignment ...	2016	26548531
using in vivo imaging to measure rna mobility in xenopus laevis oocytes.	rna localization in the xenopus oocyte is responsible for the establishment of polarity during oogenesis as well as the specification of germ layers during embryogenesis. however, the inability to monitor mrna localization in live vertebrate oocytes has posed a major barrier to understanding the mechanisms driving directional transport. here we describe a method for imaging ms2 tagged rna in live xenopus oocytes to study the dynamics of rna localization. we also focus on methods for implementing ...	2016	26546269
sex-specific response to hypoxia in a reduced brainstem preparation from xenopus laevis.	respiratory reflexes and tolerance to hypoxia show significant sexual dimorphism. however, the data supporting this notion originates exclusively from mammals. to determine whether this concept is limited to this group of vertebrates, we examined the sex-specific response to acute hypoxia in an adult reduced brainstem preparation from xenopus laevis. within the first 5min of exposure to hypoxic acsf (98% n2/2% co2), recordings of respiratory-related activity show a stronger increase in fictive b ...	2016	26528898
expression pattern of bcar3, a downstream target of gata2, and its binding partner, bcar1, during xenopus development.	primitive hematopoiesis generates red blood cells that deliver oxygen to the developing embryo. mesodermal cells commit to a primitive blood cell fate during gastrulation and, in order to do so the mesoderm must receive non-cell autonomous signals transmitted from other germ layers. in xenopus, the transcription factor gata2 functions in ectodermal cells to generate or transmit the non-cell autonomous signals. here we have identified breast cancer antiestrogen resistance 3 (bcar3) as a gene that ...	2016	26631802
differential thyroid hormone sensitivity of fast cycling progenitors in the neurogenic niches of tadpoles and juvenile frogs.	adult neurogenesis occurs in neural stem cell (nsc) niches where slow cycling stem cells give rise to faster cycling progenitors. in the adult mouse nsc niche thyroid hormone, t3, and its receptor trα act as a neurogenic switch promoting progenitor cell cycle completion and neuronal differentiation. little is known about whether and how t3 controls proliferation of differentially cycling cells during xenopus neurogenesis. to address this question, we first used sox3 as a marker of stem cell and ...	2016	26628040
in vitro model systems to investigate bile salt export pump (bsep) activity and drug interactions: a review.	the bile salt export pump protein (bsep), expressed on the canalicular membranes of hepatocytes, is primarily responsible for the biliary excretion of bile salts. the inhibition of bsep transport activity can lead to an increase in intracellular bile salt levels and liver injury. this review discusses the various in vitro assays currently available for assessing the effect of drugs or other chemical entities to modulate bsep transport activity. bsep transporter assays use one of the following pl ...	2016	26683212
atrazine and malathion shorten the maturation process of xenopus laevis oocytes and have an adverse effect on early embryo development.	the use of pesticides has a negative impact on the environment. amphibians have long been regarded as indicator species to pollutants due to their permeable skin and sensitivity to the environment. studies have shown that population declines of some amphibians are directly linked with exposure to agricultural contaminants. in the past, much of the studies have focused on the toxic effect of contaminants on larvae (tadpoles), juvenile and adult frogs. however, due to the nature of their life cycl ...	2016	26686575
amphibian macrophage development and antiviral defenses.	macrophage lineage cells represent the cornerstone of vertebrate physiology and immune defenses. in turn, comparative studies using non-mammalian animal models have revealed that evolutionarily distinct species have adopted diverse molecular and physiological strategies for controlling macrophage development and functions. notably, amphibian species present a rich array of physiological and environmental adaptations, not to mention the peculiarity of metamorphosis from larval to adult stages of ...	2016	26705159
electrophysiological characterization of na,k-atpases expressed in xenopus laevis oocytes using two-electrode voltage clamping.	the transport of three na(+) per two k(+) means that the na,k-atpase is electrogenic, and though the currents generated by the ion pump are small compared to ion channel currents, they can be measured using electrophysiology, both steady-state pumping and individual steps in the transport cycle. various electrophysiological techniques have been used to study the endogenous pumps of the squid giant axon and of cardiac myocytes from for example rabbits. here, we describe the characterization of he ...	2016	26695042
identification of methylated deoxyadenosines in vertebrates reveals diversity in dna modifications.	methylation of cytosine deoxynucleotides generates 5-methylcytosine (m(5)dc), a well-established epigenetic mark. however, in higher eukaryotes much less is known about modifications affecting other deoxynucleotides. here, we report the detection of n(6)-methyldeoxyadenosine (m(6)da) in vertebrate dna, specifically in xenopus laevis but also in other species including mouse and human. our methylome analysis reveals that m(6)da is widely distributed across the eukaryotic genome and is present in ...	2016	26689968
reappraising the effects of artemisinin on the atpase activity of pfatp6 and serca1a e255l expressed in xenopus laevis oocytes.		2016	26733217
assessing differences in toxicity and teratogenicity of three phthalates, diethyl phthalate, di-n-propyl phthalate, and di-n-butyl phthalate, using xenopus laevis embryos.	phthalates, compounds used to add flexibility to plastics, are ubiquitous in the environment. in particular, the diethyl (dep), di-n-propyl (dnpp), and di-n-butyl (dbp) phthalates were found to exert detrimental effects in both mammalian and non-mammalian studies, with toxic effects varying according to alkyl chain length. embryos of xenopus laevis, the african clawed frog, have been used to assess toxicity and teratogenicity of several compounds and serves as a model for assessing adverse and t ...	2016	26730679
hydrophobic interactions between the s5 segment and the pore helix stabilizes the closed state of slo2.1 potassium channels.	under normal physiological conditions, slo2.1k(+) channels are in a closed state unless activated by an elevation in [na(+)]i. fenamates such as niflumic acid also activate slo2.1. previous studies suggest that activation of slo2.1 channels is mediated by a conformational change in the selectivity filter, and not a widening of the aperture formed by the s6 segment bundle crossing as occurs in voltage-gated k(+) channels. it is unclear how binding of na(+) or fenamates is allosterically linked to ...	2016	26724206
single-cell mass spectrometry for discovery proteomics: quantifying translational cell heterogeneity in the 16-cell frog (xenopus) embryo.	we advance mass spectrometry from a cell population-averaging tool to one capable of quantifying the expression of diverse proteins in single embryonic cells. our instrument combines capillary electrophoresis (ce), electrospray ionization, and a tribrid ultrahigh-resolution mass spectrometer (hrms) to enable untargeted (discovery) proteomics with ca. 25 amol lower limit of detection. ce-μesi-hrms enabled the identification of 500-800 nonredundant protein groups by measuring 20 ng, or <0.2% of th ...	2016	26756663
homology-driven assembly of non-redundant protein sequence sets (nomess) for mass spectrometry.	to enable mass spectrometry (ms)-based proteomic studies with poorly characterized organisms, we developed a computational workflow for the homology-driven assembly of a non-redundant reference sequence dataset. in the automated pipeline, translated dna sequences (e.g. ests, rna deep-sequencing data) are aligned to those of a closely related and fully sequenced organism. representative sequences are derived from each cluster and joined, resulting in a non-redundant reference set representing the ...	2016	26743511
adaptive plasticity of spino-extraocular motor coupling during locomotion in metamorphosing xenopus laevis.	during swimming in the amphibian italic! xenopus laevis, efference copies of rhythmic locomotor commands produced by the spinal central pattern generator (cpg) can drive extraocular motor output appropriate for producing image-stabilizing eye movements to offset the disruptive effects of self-motion. during metamorphosis, italic! x. laevisremodels its locomotor strategy from larval tail-based undulatory movements to bilaterally synchronous hindlimb kicking in the adult. this change in propulsive ...	2016	27103674
selective inhibition of the kinase dyrk1a by targeting its folding process.	autophosphorylation of amino-acid residues is part of the folding process of various protein kinases. conventional chemical screening of mature kinases has missed inhibitors that selectively interfere with the folding process. here we report a cell-based assay that evaluates inhibition of a kinase at a transitional state during the folding process and identify a folding intermediate-selective inhibitor of dual-specificity tyrosine-phosphorylation-regulated kinase 1a (dyrk1a), which we refer to a ...	2016	27102360
mapping neurogenesis onset in the optic tectum of xenopus laevis.	neural progenitor cells have a central role in the development and evolution of the vertebrate brain. during early brain development, neural progenitors first expand their numbers through repeated proliferative divisions and then begin to exhibit neurogenic divisions. the transparent and experimentally accessible optic tectum of xenopus laevis is an excellent model system for the study of the cell biology of neurogenesis, but the precise spatial and temporal relationship between proliferative an ...	2016	27012549
neural regeneration dynamics of xenopus laevis olfactory epithelium after zinc sulfate-induced damage.	neural stem cells (nscs) of the olfactory epithelium (oe) are responsible for tissue maintenance and the neural regeneration after severe damage of the tissue. in the normal oe, nscs are located in the basal layer, olfactory receptor neurons (orns) mainly in the middle layer, and sustentacular (sus) cells in the most apical olfactory layer. in this work, we induced severe damage of the oe through treatment with a zinc sulfate (znso4) solution directly in the medium, which resulted in the loss of ...	2016	27012180
single-cell mass spectrometry with multi-solvent extraction identifies metabolic differences between left and right blastomeres in the 8-cell frog (xenopus) embryo.	single-cell metabolic mass spectrometry enables the discovery (untargeted) analysis of small molecules in individual cells. using single-cell capillary electrophoresis high-resolution mass spectrometry (ce-hrms), we recently uncovered small-molecule differences between embryonic cells located along the animal-vegetal and dorsal-ventral axes of the 16-cell frog (xenopus laevis) embryo, raising the question whether metabolic cell heterogeneity also exists along the left-right body axis. to address ...	2016	27004603
an early developmental vertebrate model for nanomaterial safety: bridging cell-based and mammalian toxicity assessment.	with the rise in production of nanoparticles (nps) for an ever-increasing number of applications, there is an urgent need to efficiently assess their potential toxicity. we propose a np hazard assessment protocol that combines mammalian cytotoxicity data with embryonic vertebrate abnormality scoring to determine an overall toxicity index.	2016	27003295
expressional characterization of mrna (guanine-7) methyltransferase (rnmt) during early development of xenopus laevis.	methylation of the guanosine cap structure at the 5' end of mrna is essential for efficient translation of all eukaryotic cellular mrnas, gene expression and cell viability and promotes transcription, splicing, polyadenylation and nuclear export of mrna. in the current study, we present the spatial expression pattern of the xenopus laevis rnmt homologue. a high percentage of protein sequence similarity, especially within the methyltransferase domain, as well as an increased expression in the cel ...	2016	27002806
identifying domains of efhc1 involved in ciliary localization, ciliogenesis, and the regulation of wnt signaling.	efhc1 encodes a ciliary protein that has been linked to juvenile myoclonic epilepsy. in ectodermal explants, derived from xenopus laevis embryos, the morpholino-mediated down-regulation of efhc1b inhibited multiciliated cell formation. in those ciliated cells that did form, axoneme but not basal body formation was inhibited. efhc1b morphant embryos displayed defects in central nervous system (cns) and neural crest patterning that were rescued by a efhc1b-gfp chimera. efhc1b-gfp localized to cili ...	2016	26783883
differential requirement of bone morphogenetic protein receptors ia (alk3) and ib (alk6) in early embryonic patterning and neural crest development.	bone morphogenetic proteins regulate multiple processes in embryonic development, including early dorso-ventral patterning and neural crest development. bmps activate heteromeric receptor complexes consisting of type i and type ii receptor-serine/threonine kinases. bmp receptors ia and ib, also known as alk3 and alk6 respectively, are the most common type i receptors that likely mediate most bmp signaling events. since early expression patterns and functions in xenopus laevis development have no ...	2016	26780949
lens regeneration from the cornea requires suppression of wnt/β-catenin signaling.	the frog, xenopus laevis, possesses a high capacity to regenerate various larval tissues, including the lens, which is capable of complete regeneration from the cornea epithelium. however, the molecular signaling mechanisms of cornea-lens regeneration are not fully understood. previous work has implicated the involvement of the wnt signaling pathway, but molecular studies have been very limited. iris-derived lens regeneration in the newt (wolffian lens regeneration) has shown a necessity for act ...	2016	26778749
using frogs faces to dissect the mechanisms underlying human orofacial defects.	in this review i discuss how xenopus laevis is an effective model to dissect the mechanisms underlying orofacial defects. this species has been particularly useful in studying the understudied structures of the developing face including the embryonic mouth and primary palate. the embryonic mouth is the first opening between the foregut and the environment and is critical for adult mouth development. the final step in embryonic mouth formation is the perforation of a thin layer of tissue covering ...	2016	26778163
ventricular cell fate can be specified until the onset of myocardial differentiation.	the mechanisms that govern specification of various cell types that constitute vertebrate heart are not fully understood. whilst most studies of heart development have utilised the mouse embryo, we have used an alternative model, embryos of the frog xenopus laevis, which permits direct experimental manipulation of a non-essential heart. we show that in this model pluripotent animal cap explants injected with cardiogenic factor gata4 mrna express pan-myocardial as well as ventricular and proepica ...	2016	26776863
high and low gaba sensitivity α4β2δ gabaa receptors are expressed in xenopus laevis oocytes with divergent stoichiometries.	gabaa receptors that contain the α4 and δ subunits are thought to be located extrasynaptically, mediating tonic currents elicited by low concentrations of gaba. these α4βδ receptors are modulated by neurosteroids and certain anesthetics, identifying them as important drug targets in research. however, pharmacological studies on these receptors have often yielded variable results, possibly due to the expression of receptors in different stoichiometries or arrangements. in this study, we injected ...	2016	26774457
proper notch activity is necessary for the establishment of proximal cells and differentiation of intermediate, distal, and connecting tubule in xenopus pronephros development.	notch signaling in pronephros development has been shown to regulate establishment of glomus and proximal tubule, but how notch signal works on competency of pronephric anlagen during the generation of pronephric components remains to be understood.	2016	26773453
retracted: the anaphase-promoting complex/cyclosome is essential for entry into meiotic m-phase.	vertebrate immature oocytes are arrested at prophase of meiosis i (mi). hormonal stimulation breaks this prophase-i arrest and induces re-entry into mi. the mechanism underlying meiotic resumption remains largely elusive. here, we demonstrate that the anaphase-promoting complex/cyclosome (apc/c) in complex with cdh1 has an unexpected function in meiosis in that it is essential for meiotic resumption. we identify the catalytic subunit of protein phosphatase 6 (pp6c) as the critical substrate whos ...	2016	26766445
energetics of photoinduced charge migration within the tryptophan tetrad of an animal (6-4) photolyase.	cryptochromes and photolyases are flavoproteins that undergo cascades of electron/hole transfers after excitation of the flavin cofactor. it was recently discovered that animal (6-4) photolyases, as well as animal cryptochromes, feature a chain of four tryptophan residues, while other members of the family contain merely a tryptophan triad. transient absorption spectroscopy measurements on xenopus laevis (6-4) photolyase have shown that the fourth residue is effectively involved in photoreductio ...	2016	26765169
[the biological activity of the sevanol and its analogues].	previously, from the plant thymus armeniacus a new lignan sevanol was isolated, it's structure was elucidated and was shown that it effectively inhibits the acid-sensing channel asic3 and also exhibits a pronounced analgesic and anti-inflammatory effect. in this work biological activity of the sevanol analog obtained by chemical synthesis from simple precursors, the stereoisomer of sevanol and a precursor molecule represents a half of sevanol was measured in electrophysiological experiments on h ...	2016	26762099
neurotransmitter signaling pathways required for normal development in xenopus laevis embryos: a pharmacological survey screen.	neurotransmitters are not only involved in brain function but are also important signaling molecules for many diverse cell types. neurotransmitters are widely conserved, from evolutionarily ancient organisms lacking nervous systems through man. here, results are reported from a loss- and gain-of-function survey, using pharmacological modulators of several neurotransmitter pathways to examine possible roles for these pathways in normal embryogenesis. applying reagents targeting the glutamatergic, ...	2016	27060969
expression and purification of the full murine npm2 and study of its interaction with protamines and histones.	mouse nucleoplasmin m.npm2 was recombinantly expressed and the protein consisting of the complete sequence was purified and characterized. similar to its xenopus laevis x.npm2 counterpart, the protein forms stable pentameric complexes and exhibits an almost undistinguishable hydrodynamic ionic strength-dependent unfolding behavior. the interaction of n.pm2 with histones and mouse p1/p2 protamines revealed that these chromosomal proteins bind preferentially to the distal part of the nucleoplasmin ...	2016	28955874
effects of cd2+ on the epithelial na+ channel (enac) investigated by experimental and modeling studies.	the function of the epithelial na+ channel from the apical membrane of many na+ transporting epithelia is modulated by various chemical compounds from the extracellular space, such as heavy metals, protons or chloride ions. we have studied the effect of extracellular cd2+ on the function of the epithelial na+ channel (enac) in heterologously expressed xenopus laevis oocytes and na+-transporting epithelia. we assayed channel function as the amiloride-sensitive sodium current (i(na)). cd2+ rapidly ...	2016	27045669
erratum: reappraising the effects of artemisinin on the atpase activity of pfatp6 and serca1a e255l expressed in xenopus laevis oocytes.		2016	27045446
identification and characterization of heptapeptide modulators of the glycine receptor.	the glycine receptor is a member of the cys-loop receptor superfamily of ligand-gated ion channels and is implicated as a possible therapeutic target for the treatment of diseases such as alcoholism and inflammatory pain. in humans, four glycine receptor subtypes (α1, α2, α3, and β) co-assemble to form pentameric channel proteins as either α homomers or αβ heteromers. to date, few agents have been identified that can selectively modulate the glycine receptor, especially those possessing subtype ...	2016	27038522
identification and functional characterization of four transient receptor potential ankyrin 1 variants in apolygus lucorum (meyer-dür).	as signal integrators that respond to various physical and chemical stimuli, transient receptor potential (trp) channels fulfil critical functional roles in the sensory systems of both vertebrate and invertebrate organisms. here, four variants of trp ankyrin 1 (trpa1) were identified and cloned from the green plant bug, apolygus lucorum. spatiotemporal expression profiling across development and in different adult tissues revealed that the highest relative-transcript levels occurred in first-ins ...	2016	27038267
[identification of a novel calcium (ca^(2+))-activated chloride channel accessory gene in xenopus laevis].	calcium (ca^(2+))-activated chloride channel accessories (clcas) are putative anion channel-related proteins with diverse physiological functions. exploring clca diversity is important for prediction of gene structure and function. in an effort to identify novel clca genes in xenopus laevis, we successfully cloned and characterized a xenopus laevis cdna predicted to encode the xclca3 gene. cloning of xclca3 was achieved by computational analysis, rapid amplification of cdna ends (race), and a ti ...	2016	27028816
evolution of heat sensors drove shifts in thermosensation between xenopus species adapted to different thermal niches.	temperature is one of the most critical environmental factors affecting survival, and thus species that inhabit different thermal niches have evolved thermal sensitivities suitable for their respective habitats. during the process of shifting thermal niches, various types of genes expressed in diverse tissues, including those of the peripheral to central nervous systems, are potentially involved in the evolutionary changes in thermosensation. to elucidate the molecular mechanisms behind the evol ...	2016	27022021
effects of gsm-like radiofrequency irradiation during the oogenesis and spermiogenesis of xenopus laevis.	we aimed to evaluate the effect of gsm-like radiofrequency electromagnetic radiation (rf-emr) on the oogenesis, and spermiogenesis of xenopus laevis, and so the development of the embryos obtained from normal females+normal males (i.e. "n(f)+n(m)"); normal females+rf-exposed males (i.e. "n(f)+rf(m)"); rf-exposed female+normal male (i.e. "rf(f)+n(m)"); and rf-exposed female+rf-exposed male (i.e. "rf(f)+rf(m)". various, assessments were performed to determine potential teratogenic effects and mort ...	2016	27017260
bioelectric signalling via potassium channels: a mechanism for craniofacial dysmorphogenesis in kcnj2-associated andersen-tawil syndrome.	xenopus laevis craniofacial development is a good system for the study of andersen-tawil syndrome (ats)-associated craniofacial anomalies (cfas) because (1) kcnj2 is expressed in the nascent face; (2) molecular-genetic and biophysical techniques are available for the study of ion-dependent signalling during craniofacial morphogenesis; (3) as in humans, expression of variant kcnj2 forms in embryos causes a muscle phenotype; and (4) variant forms of kcnj2 found in human patients, when injected int ...	2016	26864374
stem cell-like xenopus embryonic explants to study early neural developmental features in vitro and in vivo.	understanding the genetic programs underlying neural development is an important goal of developmental and stem cell biology. in the amphibian blastula, cells from the roof of the blastocoel are pluripotent. these cells can be isolated, and programmed to generate various tissues through manipulation of genes expression or induction by morphogens. in this manuscript protocols are described for the use of xenopus laevis blastocoel roof explants as an assay system to investigate key in vivo and in ...	2016	26863402
tweaking subtype selectivity and agonist efficacy at (s)-2-amino-3-(3-hydroxy-5-methyl-isoxazol-4-yl)propionic acid (ampa) receptors in a small series of bntetampa analogues.	a series of analogues of the (s)-2-amino-3-(3-hydroxy-5-methyl-isoxazol-4-yl)propionic acid (ampa) receptor agonist bntetampa (5b) were synthesized and characterized pharmacologically in radioligand binding assays at native and cloned ampa receptors and functionally by two-electrode voltage clamp electrophysiology at the four homomeric ampa receptors expressed in xenopus laevis oocytes. the analogues 6 and 7 exhibit very different pharmacological profiles with binding affinity preference for the ...	2016	26862980
unequal contribution of native south african phylogeographic lineages to the invasion of the african clawed frog, xenopus laevis, in europe.	due to both deliberate and accidental introductions, invasive african clawed frog (xenopus laevis) populations have become established worldwide. in this study, we investigate the geographic origins of invasive x. laevis populations in france and portugal using the phylogeographic structure of x. laevis in its native south african range. in total, 80 individuals from the whole area known to be invaded in france and portugal were analysed for two mitochondrial and three nuclear genes, allowing a ...	2016	26855879
a three amino acid deletion in the transmembrane domain of the nicotinic acetylcholine receptor α6 subunit confers high-level resistance to spinosad in plutella xylostella.	spinosad is a macrocyclic lactone insecticide that acts primarily at the nicotinic acetylcholine receptors (nachrs) of target insects. here we describe evidence that high levels of resistance to spinosad in the diamondback moth (plutella xylostella) are associated with a three amino acid (3-aa) deletion in the fourth transmembrane domain (tm4) of the nachr α6 subunit (pxα6). following laboratory selection with spinosad, the sz-spinr strain of p. xylostella exhibited 940-fold resistance to spinos ...	2016	26855198
making muscle: morphogenetic movements and molecular mechanisms of myogenesis in xenopus laevis.	xenopus laevis offers unprecedented access to the intricacies of muscle development. the large, robust embryos make it ideal for manipulations at both the tissue and molecular level. in particular, this model system can be used to fate map early muscle progenitors, visualize cell behaviors associated with somitogenesis, and examine the role of signaling pathways that underlie induction, specification, and differentiation of muscle. several characteristics that are unique to x. laevis include myo ...	2016	26853935
using xenopus laevis retinal and spinal neurons to study mechanisms of axon guidance in vivo and in vitro.	the intricate and precise establishment of neuronal connections in the developing nervous system relies on accurate navigation of growing axons. since ramón y cajal's discovery of the growth cone, the phenomenon of axon guidance has been revealed as a coordinated operation of guidance molecules, receptors, secondary messengers, and responses driven by the dynamic cytoskeleton within the growth cone. with the advent of new and accelerating techniques, xenopus laevis emerged as a robust model to i ...	2016	26853934
heterologous expression of melanopsin: present, problems and prospects.	melanopsin, the photosensory pigment of specialized mammalian retinal ganglion cells, is involved in various non-image forming tasks such as pupillary light reflex, circadian entrainment and irradiance detection. melanopsin genes have been detected in all vertebrate classes and are resolved in two lineages, opn4m and opn4x. in addition, two splice variants have been found in several species leading to a short (opn4-s) and a long (opn4-l) isoform, mainly differing in the length of the c terminus. ...	2016	26850932
a western blot protocol for detection of proteins heterologously expressed in xenopus laevis oocytes.	oocytes of the african clawed frog, xenopus laevis, are often used for expression and biochemical characterization of transporter proteins as the oocytes are particularly suitable for uptake assays and electrophysiological recordings. assessment of the expression level of expressed transporters at the individual oocyte level is often desirable when comparing properties of wild type and mutant transporters. however, a large content of yolk platelets in the oocyte cytoplasm makes this a challengin ...	2016	26843169
rna whole-mount in situ hybridisation proximity ligation assay (rish-pla), an assay for detecting rna-protein complexes in intact cells.	techniques for studying rna-protein interactions have lagged behind those for dna-protein complexes as a consequence of the complexities associated with working with rna. here we present a method for the modification of the existing in situ hybridisation-proximity ligation assay (ish-pla) protocol to adapt it to the study of rna regulation (rish-pla). as proof of principle we used the well-characterised interaction of the xenopus laevis staufen rna binding protein with vg1 mrna, the complex of w ...	2016	26824753
nuclear size is sensitive to ntf2 protein levels in a manner dependent on ran binding.	altered nuclear size is associated with many cancers, and determining whether cancer-associated changes in nuclear size contribute to carcinogenesis necessitates an understanding of mechanisms of nuclear size regulation. although nuclear import rates generally positively correlate with nuclear size, ntf2 levels negatively affect nuclear size, despite the role of ntf2 (also known as nutf2) in nuclear recycling of the import factor ran. we show that binding of ran to ntf2 is required for ntf2 to i ...	2016	26823604
a gradient of maternal bicaudal-c controls vertebrate embryogenesis via translational repression of mrnas encoding cell fate regulators.	vertebrate bicaudal-c (bicc1) has important biological roles in the formation and homeostasis of multiple organs, but direct experiments to address the role of maternal bicc1 in early vertebrate embryogenesis have not been reported. here, we use antisense phosphorothioate-modified oligonucleotides and the host-transfer technique to eliminate specifically maternal stores of both bicc1 mrna and bicc1 protein from xenopus laevis eggs. fertilization of these bicc1-depleted eggs produced embryos with ...	2016	26811381
pld1 regulates xenopus convergent extension movements by mediating frizzled7 endocytosis for wnt/pcp signal activation.	phospholipase d (pld) is involved in the regulation of receptor-associated signaling, cell movement, cell adhesion and endocytosis. however, its physiological role in vertebrate development remains poorly understood. in this study, we show that pld1 is required for the convergent extension (ce) movements during xenopus gastrulation by activating wnt/pcp signaling. xenopus pld1 protein is specifically enriched in the dorsal region of xenopus gastrula embryo and loss or gain-of-function of pld1 in ...	2016	26806705
hmga2 is required for neural crest cell specification in xenopus laevis.	hmga proteins are small nuclear proteins that bind dna by conserved at-hook motifs, modify chromatin architecture and assist in gene expression. two hmgas (hmga1 and hmga2), encoded by distinct genes, exist in mammals and are highly expressed during embryogenesis or reactivated in tumour progression. we here addressed the in vivo role of xenopus hmga2 in the neural crest cells (nccs). we show that hmga2 is required for normal ncc specification and development. hmga2 knockdown leads to severe dis ...	2016	26806704
alterations in gene expression levels provide early indicators of chemical stress during xenopus laevis embryo development: a case study with perfluorooctane sulfonate (pfos).	in the present study, xenopus laevis embryos were exposed to a range of perfluorooctane sulfonate (pfos) concentrations (0, 0.5, 6, 12, 24, 48 and 96mg/l) for 96h in laboratorial conditions to establish toxicity along with possible gene expression changes. mortality and deformities were monitored daily and head-tail length was measured at the end of the assay as an indicator of growth. at 24 and 96h post-exposure (hpe), the mrna expression levels of the genetic markers involved in general stress ...	2016	26802562
morphological, biochemical, transcriptional and epigenetic responses to fasting and refeeding in intestine of xenopus laevis.	amphibians are able to survive for several months without food. however, it is unclear what molecular mechanisms underlie their survival. to characterize the intestinal responses to fasting and refeeding, we investigated morphological, biochemical, transcriptional and epigenetic changes in the intestine from adult male xenopus laevis.	2016	26798452
post-translational regulation of hexokinase function and protein stability in the aestivating frog xenopus laevis.	xenopus laevis endure substantial dehydration which can impose hypoxic stress due to impaired blood flow. tissues may increase reliance on anaerobic glycolysis for energy production making the regulation of hexokinase (hk) important. we investigated the enzymatic properties and phosphorylation state of purified hk from the muscle of control and dehydrated (30% total body water lost) frogs. bioinformatic tools were also applied to analyze the structural implication of hk phosphorylation in silico ...	2016	26797504
using xenopus embryos to study transcriptional and posttranscriptional gene regulatory mechanisms of intermediate filaments.	intermediate filament genes exhibit highly regulated, tissue-specific patterns of expression during development and in response to injury. identifying the responsible cis-regulatory gene elements thus holds great promise for revealing insights into fundamental gene regulatory mechanisms controlling tissue differentiation and repair. because much of this regulation occurs in response to signals from surrounding cells, characterizing them requires a model system in which their activity can be test ...	2016	26795487
a novel synaptic plasticity rule explains homeostasis of neuromuscular transmission.	excitability differs among muscle fibers and undergoes continuous changes during development and growth, yet the neuromuscular synapse maintains a remarkable fidelity of execution. here we show in two evolutionarily distant vertebrates (xenopus laevis cell culture and mouse nerve-muscle ex-vivo) that the skeletal muscle cell constantly senses, through two identified calcium signals, synaptic events and their efficacy in eliciting spikes. these sensors trigger retrograde signal(s) that control pr ...	2016	27138195