| 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 |
| subcellular localization of class i histone deacetylases in the developing xenopus tectum. | histone deacetylases (hdacs) are thought to localize in the nucleus to regulate gene transcription and play pivotal roles in neurogenesis, apoptosis, and plasticity. however, the subcellular distribution of class i hdacs in the developing brain remains unclear. here, we show that hdac1 and hdac2 are located in both the mitochondria and the nucleus in the xenopus laevis stage 34 tectum and are mainly restricted to the nucleus following further brain development. hdac3 is widely present in the mit ... | 2015 | 26793062 |
| 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 |
| mixture toxicity of microcystin-lr, paraoxon and bromadiolone in xenopus laevis embryos. | apart from infections and habitat loss, environmental pollution is another major factor of global decline of amphibians. using the model of xenopus laevis embryos, we test the hypothesis that combined exposure of amphibians to natural toxins and anthropogenic pollutants induces more pronounced adverse effects than single exposures. | 2015 | 26757121 |
| 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 |
| fiber size-selective stimulation using action potential filtering for a peripheral nerve interface: a simulation study. | functional electrical stimulation is a powerful tool for restoration of function after nerve injury. however selectivity of stimulation remains an issue. this paper presents an alternative stimulation technique to obtain fiber size-selective stimulation of nerves using fda-approved electrode implants. the technique was simulated for the ventral roots of xenopus laevis, motivated by an application in bladder control. the technique relies on applying a high frequency alternating current to filter ... | 2015 | 26737025 |
| 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 |
| molecular and cytological analyses reveal distinct transformations of intestinal epithelial cells during xenopus metamorphosis. | the thyroid hormone (t3)-induced formation of adult intestine during amphibian metamorphosis resembles the maturation of the mammalian intestine during postembryonic development, the period around birth when plasma t3 level peaks. this process involves de novo formation of adult intestinal stem cells as well as the removal of the larval epithelial cells through apoptosis. earlier studies have revealed a number of cytological and molecular markers for the epithelial cells undergoing different cha ... | 2015 | 26719790 |
| on the embryonic cell division beyond the contractile ring mechanism: experimental and computational investigation of effects of vitelline confinement, temperature and egg size. | embryonic cell division is a mechanical process which is predominantly driven by contraction of the cleavage furrow and response of the remaining cellular matter. while most previous studies focused on contractile ring mechanisms of cytokinesis, effects of environmental factors such as pericellular vitelline membrane and temperature on the mechanics of dividing cells were rarely studied. here, we apply a model-based analysis to the time-lapse imaging data of two species (saccoglossus kowalevskii ... | 2015 | 26713241 |
| using confocal analysis of xenopus laevis to investigate modulators of wnt and shh morphogen gradients. | this protocol describes a method to visualise ligands distributed across a field of cells. the ease of expressing exogenous proteins, together with the large size of their cells in early embryos, make xenopus laevis a useful model for visualising gfp-tagged ligands. synthetic mrnas are efficiently translated after injection into early stage xenopus embryos, and injections can be targeted to a single cell. when combined with a lineage tracer such as membrane tethered rfp, the injected cell (and i ... | 2015 | 26709854 |
| 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 |
| thrombopoietin induces production of nucleated thrombocytes from liver cells in xenopus laevis. | the development of mammalian megakaryocytes (mks) and platelets, which are thought to be absent in non-mammals, is primarily regulated by the thrombopoietin (tpo)/mpl system. although non-mammals possess nucleated thrombocytes instead of platelets, the features of nucleated thrombocyte progenitors remain to be clarified. here, we provide the general features of tpo using xenopus laevis tpo (xltpo). hepatic and splenic cells were cultured in liquid suspension with recombinant xltpo. these cells d ... | 2015 | 26687619 |
| 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 |
| up-regulation of excitatory amino acid transporters eaat1 and eaat2 by ß-klotho. | klotho, a transmembrane protein expressed in chorioid plexus of the brain, kidney, and several other tissues, is required for inhibition of 1,25(oh)2d3 formation by fgf23. the extracellular domain of klotho protein could be cleaved off, thus being released into blood or cerebrospinal fluid. at least in part by exerting β-glucuronidase activity, soluble klotho regulates several ion channels and carriers. klotho protein deficiency accelerates the appearance of age related disorders including neuro ... | 2015 | 26684854 |
| 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 |
| spak and osr1 sensitive kir2.1 k+ channels. | kir2.1 (kcnj2) channels are expressed in neurons, skeletal muscle and cardiac tissue and maintain the resting membrane potential. the activity of those channels is regulated by diverse signalling molecules. the present study explored whether kir2.1 channels are sensitive to the transporter and channels regulating kinases spak (sps1-related proline/alanine-rich kinase) and osr1 (oxidative stress-responsive kinase 1), which are in turn regulated by wnk (with-no-k[lys]) kinases. | 2015 | 26673921 |
| hepatocystin is essential for trpm7 function during early embryogenesis. | mutations in protein kinase c substrate 80k-h (prkcsh), which encodes for an 80 kda protein named hepatocystin (80k-h, prkcsh), gives rise to polycystic liver disease (pcld). hepatocystin functions as the noncatalytic beta subunit of glucosidase ii, an endoplasmic reticulum (er)-resident enzyme involved in processing and quality control of newly synthesized glycoproteins. patients harboring heterozygous germline mutations in prkcsh are thought to develop renal cysts as a result of somatic loss o ... | 2015 | 26671672 |
| 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 |
| regulation of the na+,cl- coupled creatine transporter creat (slc6a8) by the janus kinase jak3. | the creatine transporter creat (slc6a8), a na+,cl- coupled transporter is expressed in diverse tissues including the brain. genetic defects of slc6a8 result in mental retardation with seizures. the present study explored the regulation of creat by janus kinase jak3, which is expressed in a variety of tissues including the brain and participates in the regulation of cell survival and differentiation of neuronal precursor cells. | 2015 | 26666525 |
| up-regulation of voltage gated k+ channels kv1.3 and kv1.5 by protein kinase pkb/akt. | the voltage gated k+ channels kv1.3 and kv1.5 contribute to the orchestration of cell proliferation. kinases participating in the regulation of cell proliferation include protein kinase b (pkb/akt). the present study thus explored whether pkb/akt modifies the abundance and function of kv1.3 and kv1.5. | 2015 | 26666245 |
| pou5f3.2-induced proliferative state of embryonic cells during gastrulation of xenopus laevis embryo. | pou class v (pou-v) transcription factors play the important role in maintenance of pluripotency and cell differentiation. pou5f3.2 (oct25), one of xenopus pou-v transcription factors, shows the zygotic expression prior to gastrulation. in order to know the molecular mechanism of pou5f3.2 expression at gastrula stage, we examined a responsiveness of pou5f3.2 to nodal signaling. animal cap assay demonstrated that xnr2 activates the gene expression of pou5f3.2. in comparative analysis of the 5'-fl ... | 2015 | 26660397 |
| the polarity protein inturned links nphp4 to daam1 to control the subapical actin network in multiciliated cells. | motile cilia polarization requires intracellular anchorage to the cytoskeleton; however, the molecular machinery that supports this process remains elusive. we report that inturned plays a central role in coordinating the interaction between cilia-associated proteins and actin-nucleation factors. we observed that knockdown of nphp4 in multiciliated cells of the xenopus laevis epidermis compromised ciliogenesis and directional fluid flow. depletion of nphp4 disrupted the subapical actin layer. co ... | 2015 | 26644512 |
| 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 |
| the differential effects of resveratrol and trans-ε-viniferin on the gaba-induced current in gabaa receptor subtypes expressed in xenopus laevis oocytes. | the natural products resveratrol and trans-ε-viniferin have been reported to have many beneficial effects, which include the enhancement of cognition and memory. there have been no studies which have reported the effects of these compounds on the different gabaa receptor subtypes and this study aimed to address this. | 2015 | 26626239 |
| analysis of neural progenitors from embryogenesis to juvenile adult in xenopus laevis reveals biphasic neurogenesis and continuous lengthening of the cell cycle. | xenopus laevis is a prominent model system for studying neural development, but our understanding of the long-term temporal dynamics of neurogenesis remains incomplete. here, we present the first continuous description of neurogenesis in x. laevis, covering the entire period of development from the specification of neural ectoderm during gastrulation to juvenile frog. we have used molecular markers to identify progenitors and neurons, short-term bromodeoxyuridine (brdu) incorporation to map the ... | 2015 | 26621828 |
| correction: integrin α5β1 function is regulated by xgipc/kermit2 mediated endocytosis during xenopus laevis gastrulation. | | 2015 | 26605543 |
| involvement of slit-robo signaling in the development of the posterior commissure and concomitant swimming behavior in xenopus laevis. | during vertebrate development, the central nervous system (cns) has stereotyped neuronal tracts (scaffolds) that include longitudinal and commissural axonal bundles, such as the medial longitudinal fascicle or the posterior commissure (pc). as these early tracts appear to guide later-developing neurons, they are thought to provide the basic framework of vertebrate neuronal circuitry. the proper construction of these neuronal circuits is thought to be a crucial step for eliciting coordinated beha ... | 2015 | 26605073 |
| involvement of the l-type amino acid transporter lat2 in the transport of 3,3'-diiodothyronine across the plasma membrane. | thyroid hormones are transported across cell membranes by transmembrane transporter proteins, for example by members of the monocarboxylate transporter (mct) and the l-type amino acid transporter (lat) families. lats consist of a light chain (e.g. lat2) and a heavy chain (cd98), which is essential for their cell surface expression and functionality. the specificity of lat2 for thyroid hormones and their metabolites and its role in their transport was not fully clear. this fact motivated us to es ... | 2015 | 26601072 |
| 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 |
| rna-seq and microarray analysis of the xenopus inner ear transcriptome discloses orthologous omim(®) genes for hereditary disorders of hearing and balance. | auditory and vestibular disorders are prevalent sensory disabilities caused by genetic and environmental (noise, trauma, chemicals) factors that often damage mechanosensory hair cells of the inner ear. development of treatments for inner ear disorders of hearing and balance relies on the use of animal models such as fish, amphibians, reptiles, birds, and non-human mammals. here, we aimed to augment the utility of the genus xenopus for uncovering genetic mechanisms essential for the maintenance o ... | 2015 | 26582541 |
| the expression of talen before fertilization provides a rapid knock-out phenotype in xenopus laevis founder embryos. | recent advances in genome editing using programmable nucleases have revolutionized gene targeting in various organisms. successful gene knock-out has been shown in xenopus, a widely used model organism, although a system enabling less mosaic knock-out in founder embryos (f0) needs to be explored in order to judge phenotypes in the f0 generation. here, we injected modified highly active transcription activator-like effector nuclease (talen) mrna to oocytes at the germinal vesicle (gv) stage, foll ... | 2015 | 26580070 |
| 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 |
| gremlin1 induces anterior-posterior limb bifurcations in developing xenopus limbs but does not enhance limb regeneration. | gremlin1 (grem1) has been previously identified as being significantly up-regulated during regeneration of xenopus laevis limbs. grem1 is an antagonist of bone morphogenetic proteins (bmps) with a known role in limb development in amniotes. it forms part of a self-regulating feedback loop linking epithelial (fgf) and mesenchymal (shh) signalling centres, thereby controlling outgrowth, anterior posterior and proximal distal patterning. spatiotemporal regulation of the same genes in developing and ... | 2015 | 26527308 |
| affinity of the heparin binding motif of noggin1 to heparan sulfate and its visualization in the embryonic tissues. | heparin binding motifs were found in many secreted proteins and it was suggested that they are responsible for retardation of the protein diffusion within the intercellular space due to the binding to heparan sulfate proteoglycanes (hspg). here we used synthetic fitc labeled heparin binding motif (hbm peptide) of the xenopus laevis secreted bmp inhibitor noggin1 to study its diffusion along the surface of the heparin beads by frap method. as a result, we have found out that diffusivity of hbm-la ... | 2015 | 26525852 |
| [role of monocarboxylate transporter in statin-induced cytotoxicity]. | although exercise and drug therapy are important to prevent progression of arteriosclerotic disease, exercise leads to an increase in muscular disorder induced by hmg-coa reductase inhibitors (statins). elucidation of this mechanism is needed to prevent the occurrence of muscular disorders. since exercise induces expression of monocarboxylate transporter (mct) 4, we focused on the association between mct4 function and statin-induced muscle injury. first, we examined the transport of l-lactate vi ... | 2015 | 26521871 |
| 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 |
| alternatively spliced isoforms of kv10.1 potassium channels modulate channel properties and can activate cyclin-dependent kinase in xenopus oocytes. | kv10.1 is a voltage-gated potassium channel expressed selectively in the mammalian brain but also aberrantly in cancer cells. in this study we identified short splice variants of kv10.1 resulting from exon-skipping events (e65 and e70) in human brain and cancer cell lines. the presence of the variants was confirmed by northern blot and rnase protection assays. both variants completely lacked the transmembrane domains of the channel and produced cytoplasmic proteins without channel function. in a ... | 2015 | 26518875 |
| novel reporter for faithful monitoring of erk2 dynamics in living cells and model organisms. | uncoupling of erk1/2 phosphorylation from subcellular localization is essential towards the understanding of molecular mechanisms that control erk1/2-mediated cell-fate decision. erk1/2 non-catalytic functions and discoveries of new specific anchors responsible of the subcellular compartmentalization of erk1/2 signaling pathway have been proposed as regulation mechanisms for which dynamic monitoring of erk1/2 localization is necessary. however, studying the spatiotemporal features of erk2, for i ... | 2015 | 26517832 |
| identification and bioinformatics analyses of the basic helix-loop-helix transcription factors in xenopus laevis. | xenopus laevis is a long established model organism for developmental, behavioral and neurological studies. herein, an updated genome-wide survey was conducted using the ongoing genome project of xenopus laevis and 106 non-redundant basic helix-loop-helix (bhlh) genes were identified in the xenopus laevis genome databases. gene ontology (go) enrichment statistics showed 51 significant go annotations of biological processes and molecular functions and 5 significant kegg pathways and a number of x ... | 2015 | 26506645 |
| up-regulation of intestinal phosphate transporter napi-iib (slc34a2) by the kinases spak and osr1. | spak (sps1-related proline/alanine-rich kinase) and osr1 (oxidative stress-responsive kinase 1), kinases controlled by wnk (with-no-k[lys] kinase), are powerful regulators of cellular ion transport and blood pressure. observations in gene-targeted mice disclosed an impact of spak/osr1 on phosphate metabolism. the present study thus tested whether spak and/or osr1 contributes to the regulation of the intestinal na(+)-coupled phosphate co-transporter napi-iib (slc34a2). | 2015 | 26506223 |
| a database of microrna expression patterns in xenopus laevis. | micrornas (mirnas) are short, non-coding rnas around 22 nucleotides long. they inhibit gene expression either by translational repression or by causing the degradation of the mrnas they bind to. many are highly conserved amongst diverse organisms and have restricted spatio-temporal expression patterns during embryonic development where they are thought to be involved in generating accuracy of developmental timing and in supporting cell fate decisions and tissue identity. we determined the expres ... | 2015 | 26506012 |
| dose-dependent early life stage toxicities in xenopus laevis exposed in ovo to selenium. | selenium (se) is a developmental toxicant in oviparous vertebrates. the adverse reproductive effects of se toxicity have been predominantly investigated in fishes and birds with only a few studies focusing on amphibians. the objective of this study was to determine tissue-based toxicity thresholds for early life stage se toxicities in xenopus laevis as a consequence of in ovo exposure through maternal transfer of dietary se. following a 68-day dietary exposure to food augmented with l-selenometh ... | 2015 | 26501870 |
| 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 |
| rhodopsin forms nanodomains in rod outer segment disc membranes of the cold-blooded xenopus laevis. | rhodopsin forms nanoscale domains (i.e., nanodomains) in rod outer segment disc membranes from mammalian species. it is unclear whether rhodopsin arranges in a similar manner in amphibian species, which are often used as a model system to investigate the function of rhodopsin and the structure of photoreceptor cells. moreover, since samples are routinely prepared at low temperatures, it is unclear whether lipid phase separation effects in the membrane promote the observed nanodomain organization ... | 2015 | 26492040 |
| corrigendum: fertilization competence of the egg-coating envelope is regulated by direct interaction of dicalcin and gp41, the xenopus laevis zp3. | | 2015 | 26488680 |
| in vivo study of dynamics and stability of dendritic spines on olfactory bulb interneurons in xenopus laevis tadpoles. | dendritic spines undergo continuous remodeling during development of the nervous system. their stability is essential for maintaining a functional neuronal circuit. spine dynamics and stability of cortical excitatory pyramidal neurons have been explored extensively in mammalian animal models. however, little is known about spiny interneurons in non-mammalian vertebrate models. in the present study, neuronal morphology was visualized by single-cell electroporation. spiny neurons were surveyed in ... | 2015 | 26485435 |
| the hydroxyl side chain of a highly conserved serine residue is required for cation selectivity and substrate transport in the glial glutamate transporter glt-1/slc1a2. | glutamate transporters maintain synaptic concentration of the excitatory neurotransmitter below neurotoxic levels. their transport cycle consists of cotransport of glutamate with three sodium ions and one proton, followed by countertransport of potassium. structural studies proposed that a highly conserved serine located in the binding pocket of the homologous gltph coordinates l-aspartate as well as the sodium ion na1. to experimentally validate these findings, we generated and characterized se ... | 2015 | 26483543 |
| functional characterization of a transition metal ion transporter, oszip6 from rice (oryza sativa l.). | micronutrients are important for the growth and development of plants, which deploy families of transporters for their uptake and distribution. we have functionally characterized a novel transition metal ion transporter from rice, oszip6 (oryza sativa zinc regulated transporter, iron regulated transporter-like protein 6). the transporter was found to be transcriptionally activated in shoot and root tissues in response to deficiency in fe(2+), zn(2+) and mn(2+). oszip6 was expressed in xenopus la ... | 2015 | 26476396 |
| cell cycle control in the early embryonic development of aquatic animal species. | the cell cycle is integrated with many aspects of embryonic development. not only is proper control over the pace of cell proliferation important, but also the timing of cell cycle progression is coordinated with transcription, cell migration, and cell differentiation. due to the ease with which the embryos of aquatic organisms can be observed and manipulated, they have been a popular choice for embryologists throughout history. in the cell cycle field, aquatic organisms have been extremely impo ... | 2015 | 26475527 |
| 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 |
| the xenopus tropicalis orthologue of trpv3 is heat sensitive. | thermosensitive members of the transient receptor potential (trp) family of ion channels (thermal trp channels) play a crucial role in mammalian temperature sensing. orthologues of these channels are present in lower vertebrates and, remarkably, some thermal trp orthologues from different species appear to mediate opposing responses to temperature. for example, whereas the mammalian trpv3 channel is activated by heat, frog trpv3 is reportedly activated by cold. intrigued by the potential implica ... | 2015 | 26458875 |
| the scd6/lsm14 protein xrapb has properties different from rap55 in selecting mrna for early translation or intracellular distribution in xenopus oocytes. | oocytes accumulate mrnas in the form of maternal ribonucleoprotein (rnp) particles, the protein components of which determine the location and stability of individual mrnas prior to translation. scd6/lsm14 proteins, typified by rap55, function in a wide range of eukaryotes in repressing translation and relocating mrnps to processing bodies and stress granules. in xenopus laevis, the rap55 orthologue xrapa fulfils these functions. here we describe the properties of a variant of xrapa, xrapb, whic ... | 2015 | 26455898 |
| rho kinase is required to prevent retinal axons from entering the contralateral optic nerve. | to grow out to contact target neurons an axon uses its distal tip, the growth cone, as a sensor of molecular cues that help the axon make appropriate guidance decisions at a series of choice points along the journey. in the developing visual system, the axons of the output cells of the retina, the retinal ganglion cells (rgcs), cross the brain midline at the optic chiasm. shortly after, they grow past the brain entry point of the optic nerve arising from the contralateral eye, and extend dorso-c ... | 2015 | 26455469 |
| ca(2+)-bk channel clusters in olfactory receptor neurons and their role in odour coding. | olfactory receptor neurons (orns) have high-voltage-gated ca(2+) channels whose physiological impact has remained enigmatic since the voltage-gated conductances in this cell type were first described in the 1980s. here we show that in orn somata of xenopus laevis tadpoles these channels are clustered and co-expressed with large-conductance potassium (bk) channels. we found approximately five clusters per orn and twelve ca(2+) channels per cluster. the action potential-triggered activation of bk ... | 2015 | 26452167 |
| serotonergic regulation of melanocyte conversion: a bioelectrically regulated network for stochastic all-or-none hyperpigmentation. | experimentally induced depolarization of resting membrane potential in "instructor cells" in xenopus laevis embryos causes hyperpigmentation in an all-or-none fashion in some tadpoles due to excess proliferation and migration of melanocytes. we showed that this stochastic process involved serotonin signaling, adenosine 3',5'-monophosphate (camp), and the transcription factors camp response element-binding protein (creb), sox10, and slug. transcriptional microarray analysis of embryos taken at st ... | 2015 | 26443706 |
| putting it all on pigmentation: heuristics of a bold and stochastic cell fate decision. | gradients of transmembrane potential coordinate cell-fate decisions and patterning during embryogenesis and wound-healing. bioelectrical signaling may also be more important for adult pathologies than currently recognized. in this issue of science signaling, lobikin et al. describe a role for bioelectric signals during the development of xenopus leavis embryos to instruct an organism-level response reminiscent of neoplastic progression in melanoma. | 2015 | 26443702 |
| dual processing of sulfated steroids in the olfactory system of an anuran amphibian. | chemical communication is widespread in amphibians, but if compared to later diverging tetrapods the available functional data is limited. the existing information on the vomeronasal system of anurans is particularly sparse. amphibians represent a transitional stage in the evolution of the olfactory system. most species have anatomically separated main and vomeronasal systems, but recent studies have shown that in anurans their molecular separation is still underway. sulfated steroids function a ... | 2015 | 26441543 |
| xenopus laevis as a model to identify translation impairment. | protein synthesis is a fundamental process to gene expression impacting diverse biological processes notably adaptation to environmental conditions. the initiation step, which involves the assembly of the ribosomal subunits at the mrna initiation codon, involved initiation factor including eif4g1. defects in this rate limiting step of translation are linked to diverse disorders. to study the potential consequences of such deregulations, xenopus laevis oocytes constitute an attractive model with ... | 2015 | 26437037 |
| the phytosiderophore efflux transporter tom2 is involved in metal transport in rice. | iron is an essential metal element for all living organisms. graminaceous plants produce and secrete mugineic acid family phytosiderophores from their roots to acquire iron in the soil. phytosiderophores chelate and solubilize insoluble iron hydroxide in the soil. subsequently, plants take up iron-phytosiderophore complexes through specific transporters on the root cell membrane. phytosiderophores are also thought to be important for the internal transport of various transition metals, including ... | 2015 | 26432636 |
| tebuconazole disrupts steroidogenesis in xenopus laevis. | a 27-day controlled exposure study of adult male african clawed frogs (xenopus laevis) was conducted to examine the mechanism by which tebuconazole may disrupt steroidogenesis. the fungicide was measured by lc-ms/ms in tank water and in target tissues (adipose, kidney, liver, and brain), and we observed tissue-specific bioconcentration with bcf up to 238. up to 10 different steroid hormones were quantified in gonads using lc-ms/ms and in plasma using gc-ms/ms and a radioimmunoassay was performed ... | 2015 | 26432166 |
| extinction of an introduced warm-climate alien species, xenopus laevis, by extreme weather events. | invasive, non-native species represent a major threat to biodiversity worldwide. the african amphibian xenopus laevis is widely regarded as an invasive species and a threat to local faunas. populations originating at the western cape, south africa, have been introduced on four continents, mostly in areas with a similar mediterranean climate. some introduced populations are also established in cooler environments where persistence for many decades suggests a capacity for long-term adaptation. in ... | 2017 | 26430383 |
| concentration-dependent effects of nuclear lamins on nuclear size in xenopus and mammalian cells. | a fundamental question in cell biology concerns the regulation of organelle size. while nuclear size is exquisitely controlled in different cell types, inappropriate nuclear enlargement is used to diagnose and stage cancer. clarifying the functional significance of nuclear size necessitates an understanding of the mechanisms and proteins that control nuclear size. one structural component implicated in the regulation of nuclear morphology is the nuclear lamina, a meshwork of intermediate lamin f ... | 2015 | 26429910 |
| 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 |
| biochemical and hematologic reference intervals for aged xenopus laevis in a research colony. | xenopus laevis, the african clawed frog, is commonly used in developmental and toxicology research studies. little information is available on aged x. laevis; however, with the complete mapping of the genome and the availability of transgenic animal models, the number of aged animals in research colonies is increasing. the goals of this study were to obtain biochemical and hematologic parameters to establish reference intervals for aged x. laevis and to compare results with those from young adul ... | 2015 | 26424243 |