| anp and cnp activate cftr expressed in xenopus laevis oocytes by direct activation of pka. | acting through different receptors, natriuretic peptides (atrial natriuretic peptide [anp], brain type natriuretic peptide [bnp] and c-type natriuretic peptide [cnp]) increase intracellular cgmp, which then stimulates different pathways that activate fluid secretion. | 2015 | 26016495 |
| centrin-2 (cetn2) mediated regulation of fgf/fgfr gene expression in xenopus. | centrins (cetns) are highly conserved, widely expressed, and multifunctional ca(2+)-binding eukaryotic signature proteins best known for their roles in ciliogenesis and as critical components of the global genome nucleotide excision repair system. two distinct cetn subtypes, cetn2-like and cetn3-like, have been recognized and implicated in a range of cellular processes. in the course of morpholino-based loss of function studies in xenopus laevis, we have identified a previously unreported cetn2- ... | 2015 | 26014913 |
| xenopus tacc1 is a microtubule plus-end tracking protein that can regulate microtubule dynamics during embryonic development. | microtubule plus-end dynamics are regulated by a family of proteins called plus-end tracking proteins (+tips). we recently demonstrated that the transforming acidic coiled-coil (tacc) domain family member, tacc3, can function as a +tip to regulate microtubule dynamics in xenopus laevis embryonic cells. although it has been previously reported that tacc3 is the only tacc family member that exists in xenopus, our examination of its genome determined that xenopus, like all other vertebrates, contai ... | 2015 | 26012630 |
| bimodal interaction of mammalian polo-like kinase 1 and a centrosomal scaffold, cep192, in the regulation of bipolar spindle formation. | serving as microtubule-organizing centers, centrosomes play a key role in forming bipolar spindles. the mechanism of how centrosomes promote bipolar spindle assembly in various organisms remains largely unknown. a recent study with xenopus laevis egg extracts suggested that the plk1 ortholog plx1 interacts with the phospho-t46 (p-t46) motif of xenopus cep192 (xcep192) to form an xcep192-mediated xaura-plx1 cascade that is critical for bipolar spindle formation. here, we demonstrated that in cult ... | 2015 | 26012549 |
| paraxis is required for somite morphogenesis and differentiation in xenopus laevis. | in most vertebrates, the segmentation of the paraxial mesoderm involves the formation of metameric units called somites through a mesenchymal-epithelial transition. however, this process is different in xenopus laevis because it does not form an epithelial somite. xenopus somitogenesis is characterized by a complex cells rearrangement that requires the coordinated regulation of cell shape, adhesion, and motility. the molecular mechanisms that control these cell behaviors underlying somite format ... | 2015 | 26010523 |
| identification of distal enhancers for six2 expression in pronephros. | the embryonic nephric mesenchyme contains pluripotent progenitor cells. six2, a homeodomain transcription factor, is expressed in a subset of the nephric mesenchyme, and it functions to maintain a progenitor state by suppressing nephrogenesis. despite the functional significance of six2 in nephric development, its regulatory mechanisms remain unclear. to identify the cis-regulatory elements for six2, we focused on the evolutionarily conserved sequences known as conserved noncoding sequences (cns ... | 2015 | 26009236 |
| preparation of xenopus laevis retinal cryosections for electron microscopy. | transmission electron microscopy is the gold standard for examination of photoreceptor outer segment morphology and photoreceptor outer segment abnormalities in transgenic animal models of retinal disease. small vertebrates such as zebrafish and xenopus laevis tadpoles have been used to generate retinal disease models and to study outer segment processes such as protein trafficking, and their breeding capabilities facilitate experiments involving large numbers of animals and conditions. however, ... | 2015 | 26008144 |
| protein-carbohydrate interaction between sperm and the egg-coating envelope and its regulation by dicalcin, a xenopus laevis zona pellucida protein-associated protein. | protein-carbohydrate interaction regulates multiple important processes during fertilization, an essential biological event where individual gametes undergo intercellular recognition to fuse and generate a zygote. in the mammalian female reproductive tract, sperm temporarily adhere to the oviductal epithelium via the complementary interaction between carbohydrate-binding proteins on the sperm membrane and carbohydrates on the oviductal cells. after detachment from the oviductal epithelium at the ... | 2015 | 26007194 |
| dynein-based accumulation of membranes regulates nuclear expansion in xenopus laevis egg extracts. | nuclear size changes dynamically during development and has long been observed to correlate with the space surrounding the nucleus, as well as with the volume of the cell. here we combine an in vitro cell-free system of xenopus laevis egg extract with microfluidic devices to systematically analyze the effect of spatial constraints. the speed of nuclear expansion depended on the available space surrounding the nucleus up to a threshold volume in the nanoliter range, herein referred to as the nucl ... | 2015 | 26004509 |
| formation of a new limb bud at the boundary between a transplanted limb bud and the tail surface of xenopus tadpoles. | through transplantation experiments with xenopus laevis tadpoles, we found a new morphogenetic phenomenon consisting of limb bud formation at the boundary between transplanted whole limb buds and the tail surface. this phenomenon occurs without limb-limb stump interaction and has a number of unique features: (1) only one extra limb bud was formed per transplant and the new limb and the transplanted limb were bilaterally symmetrical, forming a pair of limb girdles. (2) extra new limb bud formatio ... | 2015 | 26003976 |
| asymmetrical allocation of jak1 mrna during spermatogonial stem cell division in xenopus laevis. | during xenopus spermatogenesis, each primary spermatogonium (pg), the largest single cell in the testis, undergoes mitotic divisions with a concomitant decrease in size to produce smaller differentiating spermatogonia. the spermatogonial stem cells (sscs) occur in this pg population. taking advantage of identifiable and isolatable properties of xenopus sscs, we examined jak1 gene expression during the spermatogenesis because there have been reports on the important role of jak/stat pathway in re ... | 2015 | 25988600 |
| in vitro and in vivo evidence for active brain uptake of the ghb analog hocpca by the monocarboxylate transporter subtype 1. | γ-hydroxybutyric acid (ghb) is a recreational drug, a clinically prescribed drug in narcolepsy and alcohol dependence, and an endogenous substance that binds to both high- and low-affinity sites in the brain. for studying the molecular mechanisms and the biologic role of the ghb high-affinity binding sites, ligands with high and specific affinity are essential. the conformationally restricted ghb analog hocpca (3-hydroxycyclopent-1-enecarboxylic acid) is one such compound. the objective of this ... | 2015 | 25986445 |
| expressing and characterizing mechanosensitive channels in xenopus oocytes. | the oocytes of the african clawed frog (xenopus laevis) comprise one of the most widely used membrane protein expression systems. while frequently used for studies of transporters and ion channels, the application of this system to the study of mechanosensitive ion channels has been overlooked, perhaps due to a relative abundance of native expression systems. recent advances, however, have illustrated the advantages of the oocyte system for studying plant and bacterial mechanosensitive channels. ... | 2015 | 25981775 |
| ethanol modulation is quantitatively determined by the transmembrane domain of human α1 glycine receptors. | mutagenesis and labeling studies have identified amino acids from the human α1 glycine receptor (glyr) extracellular, transmembrane (tm), and intracellular domains in mediating ethanol (etoh) potentiation. however, limited high-resolution structural data for physiologically relevant receptors in this cys-loop receptor superfamily have made pinpointing the critical amino acids difficult. homologous ion channels from lower organisms provide conserved models for structural and functional properties ... | 2015 | 25973519 |
| 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 |
| involvement of histidine residue his382 in ph regulation of mct4 activity. | monocarboxylate transporter 4 (mct4) is a ph-dependent bi-directional lactate transporter. transport of lactate via mct4 is increased by extracellular acidification. we investigated the critical histidine residue involved in ph regulation of mct4 function. transport of lactate via mct4 was measured by using a xenopus laevis oocyte expression system. mct4-mediated lactate transport was inhibited by zn2+ in a ph physiological condition but not in an acidic condition. the histidine modifier depc (d ... | 2014 | 25919709 |
| deconstructing cartilage shape and size into contributions from embryogenesis, metamorphosis, and tadpole and frog growth. | understanding skeletal diversification involves knowing not only how skeletal rudiments are shaped embryonically, but also how skeletal shape changes throughout life. the pharyngeal arch (pa) skeleton of metamorphosing amphibians persists largely as cartilage and undergoes two phases of development (embryogenesis and metamorphosis) and two phases of growth (larval and post-metamorphic). though embryogenesis and metamorphosis produce species-specific features of pa cartilage shape, the extents to ... | 2015 | 25913729 |
| urotensin ii upregulates migration and cytokine gene expression in leukocytes of the african clawed frog, xenopus laevis. | urotensin ii (uii) exhibits diverse physiological actions including vasoconstriction, locomotor activity, osmoregulation, and immune response via the uii receptor (utr) in mammals. however, in amphibians the function of the uii-utr system remains unknown. in the present study, we investigated the potential immune function of uii using leukocytes isolated from the african clawed frog, xenopus laevis. stimulation of male frogs with lipopolysaccharide increased mrna expression of uii and utr in leu ... | 2015 | 25907658 |
| transport function of rice amino acid permeases (aaps). | the transport function of four rice (oryza sativa) amino acid permeases (aaps), osaap1 (os07g04180), osaap3 (os06g36180), osaap7 (os05g34980) and osaap16 (os12g08090), was analyzed by expression in xenopus laevis oocytes and electrophysiology. osaap1, osaap7 and osaap16 functioned, similarly to arabidopsis aaps, as general amino acid permeases. osaap3 had a distinct substrate specificity compared with other rice or arabidopsis aaps. osaap3 transported the basic amino acids lysine and arginine we ... | 2015 | 25907566 |
| influence of hydrophobic residues on the activity of the antimicrobial peptide magainin 2 and its synergy with pgla. | magainin 2 (mag2) and pgla are two related antimicrobial peptides found in the skin of the african frog xenopus laevis with a pronounced synergistic activity, which act by permeabilizing bacterial membranes. to probe the influence of hydrophobic peptide-lipid and peptide-peptide interactions on the antimicrobial activity and on synergy, the sequence of mag2 was modified by replacing single amino acids either with a small alanine or with the stiff and bulky hydrophobic 3-(trifluoromethyl)-l-bicyc ... | 2015 | 25898805 |
| the influence of artificially introduced n-glycosylation sites on the in vitro activity of xenopus laevis erythropoietin. | erythropoietin (epo), the primary regulator of erythropoiesis, is a heavily glycosylated protein found in humans and several other mammals. intriguingly, we have previously found that epo in xenopus laevis (xlepo) has no n-glycosylation sites, and cross-reacts with the human epo (huepo) receptor despite low homology with huepo. in this study, we introduced n-glycosylation sites into wild-type xlepo at the positions homologous to those in huepo, and tested whether the glycosylated mutein retained ... | 2015 | 25898205 |
| targeted gene disruption in xenopus laevis using crispr/cas9. | | 2015 | 25897376 |
| glutamylation of nap1 modulates histone h1 dynamics and chromosome condensation in xenopus. | linker histone h1 is required for mitotic chromosome architecture in xenopus laevis egg extracts and, unlike core histones, exhibits rapid turnover on chromatin. mechanisms regulating the recruitment, deposition, and dynamics of linker histones in mitosis are largely unknown. we found that the cytoplasmic histone chaperone nucleosome assembly protein 1 (nap1) associates with the embryonic isoform of linker histone h1 (h1m) in egg extracts. immunodepletion of nap1 decreased h1m binding to mitotic ... | 2015 | 25897082 |
| left-right patterning in xenopus conjoined twin embryos requires serotonin signaling and gap junctions. | a number of processes operating during the first cell cleavages enable the left-right (lr) axis to be consistently oriented during xenopus laevis development. prior work showed that secondary organizers induced in frog embryos after cleavage stages (i.e. conjoined twins arising from ectopic induced primary axes) correctly pattern their own lr axis only when a primary (early) organizer is also present. this instructive effect confirms the unique lr patterning functions that occur during early emb ... | 2014 | 25896280 |
| optogenetics in developmental biology: using light to control ion flux-dependent signals in xenopus embryos. | developmental bioelectricity, electrical signaling among non-excitable cells, is now known to regulate proliferation, apoptosis, gene expression, and patterning during development. the extraordinary temporal and spatial resolution offered by optogenetics could revolutionize the study of bioelectricity the same way it has revolutionized neuroscience. there is, however, no guide to adapting optogenetics to patterning systems. to fill this gap, we used optogenetic reagents, both proteins and photoc ... | 2014 | 25896279 |
| notch is a direct negative regulator of the dna-damage response. | the dna-damage response (ddr) ensures genome stability and proper inheritance of genetic information, both of which are essential to survival. it is presently unclear to what extent other signaling pathways modulate ddr function. here we show that notch receptor binds and inactivates atm kinase and that this mechanism is evolutionarily conserved in caenorhabditis elegans, xenopus laevis and humans. in c. elegans, the notch pathway impairs ddr signaling in gonad germ cells. in mammalian cells, ac ... | 2015 | 25895060 |
| identification and expression of an atypical isoform of metallothionein in the african clawed frog xenopus laevis. | exploiting the annotation of the western clawed frog silurana tropicalis genome, we identified a new metallothionein (mt) gene, exhibiting all the features to be considered an active gene, but with an atypical coding region, showing only 17 cysteine residues instead of the canonical 20 cysteines of vertebrate metallothioneins and two anomalous cysteine triplets. however, the presence of a gene in the genome does not ensure its effective expression. by using conventional and real-time pcr analyse ... | 2015 | 25882350 |
| impact of maternal n-3 polyunsaturated fatty acid deficiency on dendritic arbor morphology and connectivity of developing xenopus laevis central neurons in vivo. | docosahexaenoic acid (dha, 22:6n-3) is an essential component of the nervous system, and maternal n-3 polyunsaturated fatty acids (pufas) are an important source for brain development. here, the impact of dha on developing central neurons was examined using an accessible in vivo model. xenopus laevis embryos from adult female frogs fed n-3 pufa-adequate or deficient diets were analyzed every 10 weeks for up to 60 weeks, when frogs were then switched to a fish oil-supplemented diet. lipid analysi ... | 2015 | 25878281 |
| neutrophil elastase activates protease-activated receptor-2 (par2) and transient receptor potential vanilloid 4 (trpv4) to cause inflammation and pain. | proteases that cleave protease-activated receptor-2 (par(2)) at arg(36)↓ser(37) reveal a tethered ligand that binds to the cleaved receptor. par(2) activates transient receptor potential (trp) channels of nociceptive neurons to induce neurogenic inflammation and pain. although proteases that cleave par(2) at non-canonical sites can trigger distinct signaling cascades, the functional importance of the par(2)-biased agonism is uncertain. we investigated whether neutrophil elastase, a biased agonis ... | 2015 | 25878251 |
| a new nomenclature of xenopus laevis chromosomes based on the phylogenetic relationship to silurana/xenopus tropicalis. | xenopus laevis (xla) is an allotetraploid species which appears to have undergone whole-genome duplication after the interspecific hybridization of 2 diploid species closely related to silurana/xenopus tropicalis (xtr). previous cdna fluorescence in situ hybridization (fish) experiments have identified 9 sets of homoeologous chromosomes in x. laevis, in which 8 sets correspond to chromosomes 1-8 of x. tropicalis (xtr1-xtr8), and the last set corresponds to a fusion of xtr9 and xtr10. in addition ... | 2015 | 25871511 |
| identification of a novel dehydration responsive gene, drp10, from the african clawed frog, xenopus laevis. | during periods of environmental stress a number of different anuran species employ adaptive strategies to promote survival. our study found that in response to dehydration (i.e., loss of total body water content), the african clawed frog (xenopus laevis) increased the expression of a novel gene (drp10) that encodes a structural homolog of the freeze-responsive fr10 protein found in wood frogs. similar to fr10, the drp10 protein was found to also contain a highly conserved n-terminal cleavable si ... | 2015 | 25866033 |
| germ layer formation during xenopus embryogenesis: the balance between pluripotency and differentiation. | the african clawed frog, xenopus laevis, has long been a model animal for the studies in the fields of animal cloning, developmental biology, biochemistry, cell biology, and physiology. with the aid of xenopus, major molecular mechanisms that are involved in embryonic development have been understood. germ layer formation is the first event of embryonic cellular differentiation, which is induced by a few key maternal factors and subsequently by zygotic signals. meanwhile, another type of signals ... | 2015 | 25862657 |
| toxic mechanisms of copper oxide nanoparticles in epithelial kidney cells. | cuo nps have previously been reported as toxic to a range of cell cultures including kidney epithelial cells from the frog, xenopus laevis (a6). here we examine the molecular mechanisms affecting toxicity of cu in different forms and particle sizes. a6 cells were exposed to ionic cu (cu2+) or cuo particles of three different sizes: cuo nps of 6 nm (np6), larger poly-dispersed cuo nps of <100 nm (poly) and cuo micro particles of <5 μm (micro), at 200 μm, equal to 12.7 mg cu/l. poly was significan ... | 2015 | 25862124 |
| a requirement for hedgehog signaling in thyroid hormone-induced postembryonic intestinal remodeling. | intestinal remodeling during amphibian metamorphosis has long been studied as a model for the formation of the adult organs in vertebrates, especially the formation of adult organ-specific stem cells. like all other processes during metamorphosis, this process is controlled by thyroid hormone (t3), which affects cell fate and behavior through transcriptional regulation of target genes by binding to t3 receptors (trs). earlier studies have shown that sonic hedgehog (shh) is induced by t3 in the d ... | 2015 | 25859319 |
| functional characterization of the human facilitative glucose transporter 12 (glut12) by electrophysiological methods. | glut12 is a member of the facilitative family of glucose transporters. the goal of this study was to characterize the functional properties of glut12, expressed in xenopus laevis oocytes, using radiotracer and electrophysiological methods. our results showed that glut12 is a facilitative sugar transporter with substrate selectivity: d-glucose ≥ α-methyl-d-glucopyranoside (α-mg) > 2-deoxy-d-glucose(2-dog) > d-fructose = d-galactose. α-mg is a characteristic substrate of the na(+)/glucose (sglt) f ... | 2015 | 25855082 |
| atp4a is required for development and function of the xenopus mucociliary epidermis - a potential model to study proton pump inhibitor-associated pneumonia. | proton pump inhibitors (ppis), which target gastric h(+)/k(+)atpase (atp4), are among the most commonly prescribed drugs. ppis are used to treat ulcers and as a preventative measure against gastroesophageal reflux disease in hospitalized patients. ppi treatment correlates with an increased risk for airway infections, i.e. community- and hospital-acquired pneumonia. the cause for this correlation, however, remains elusive. the xenopus embryonic epidermis is increasingly being used as a model to s ... | 2015 | 25848696 |
| fmrp regulates neurogenesis in vivo in xenopus laevis tadpoles. | fragile x syndrome (fxs) is the leading known monogenic form of autism and the most common form of inherited intellectual disability. fxs results from silencing the fmr1 gene during embryonic development, leading to loss of fragile x mental retardation protein (fmrp), an rna-binding protein that regulates mrna transport, stability, and translation. fxs is commonly thought of as a disease of synaptic dysfunction, however, fmrp expression is lost early in embryonic development, well before most sy ... | 2017 | 25844398 |
| desflurane increased the activity of excitatory amino-acid carrier 1 (eaac1) expressed in xenopus oocytes. | desflurane is a volatile anaesthetic agent with neuroprotective properties. excitatory amino-acid carrier 1 (eaac1) may be neuroprotective by taking up glutamate and cysteine. therefore, the effects of desflurane on eaac1 activity were investigated in this study. eaac1 was expressed in xenopus laevis oocytes. two-electrode voltage-clamping technique was used to record membrane currents upon exposure to l-glutamate (30 μm) in the presence or absence of desflurane (0.4, 1.0, 2.0, 2.6, or 3.2mm). c ... | 2015 | 25840279 |
| in vivo investigation of cilia structure and function using xenopus. | cilia are key organelles in development and homeostasis. the ever-expanding complement of cilia associated proteins necessitates rapid and tractable models for in vivo functional investigation. xenopus laevis provides an attractive model for such studies, having multiple ciliated populations, including primary and multiciliated tissues. the rapid external development of xenopus and the large cells make it an especially excellent platform for imaging studies. here we present embryological and cel ... | 2015 | 25837389 |
| reproductive strategies of the kangaroo leech, marsupiobdella africana (glossiphoniidae). | the kangaroo leech, marsupiobdella africana, is a hermaphroditic organism, with insemination taking place by the planting of a spermatophore on another leech. spermatophores are mostly planted on the anterior of the recipient leech, but not always. several spermatophores may be planted by different leeches on a single recipient. the spermatophore consists of two side by side lobes. within minutes from planting of the spermatophore, the contents are squeezed out and into the body of the recipient ... | 2015 | 25830114 |
| evidence for a revised ion/substrate coupling stoichiometry of gaba transporters. | plasma membrane γ-aminobutyric acid (gaba) transporters (gats) are electrogenic transport proteins that couple the cotranslocation of na(+), cl(-), and gaba across the plasma membrane of neurons and glia. a fundamental property of the transporter that determines its ability to concentrate gaba in cells and, hence, regulate synaptic and extra-synaptic gaba concentrations, is the ion/substrate coupling stoichiometry. here, we scrutinized the currently accepted 2 na(+):1 cl(-):1 gaba stoichiometry ... | 2015 | 25824654 |
| a 90 day safety assessment of genetically modified rice expressing cry1ab/1ac protein using an aquatic animal model. | in fields of transgenic bt rice, frogs are exposed to bt proteins through consumption of both target and nontarget insects. in the present study, we assessed the risk posed by transgenic rice expressing a cry1ab/1ac fusion protein (huahui 1, hh1) on the development of xenopus laevis. for 90 days, froglets were fed a diet with 30% hh1 rice, 30% parental rice (minghui 63, mh63), or no rice as a control. body weight and length were measured every 15 days. after sacrificing the froglets, we performe ... | 2015 | 25822065 |
| toxicity evaluation of a new zn-doped cuo nanocomposite with highly effective antibacterial properties. | the increased resistances to conventional antibiotics determine a strong need for new antibacterials, and specific syntheses at the nanoscale promise to be helpful in this field. a novel zinc-doped copper oxide nanocomposite (nzn-cuo) has been recently sonochemically synthesized and successfully tested also against multi-drug resistant bacteria. after synthesis and characterization of the physicochemical properties, the new nzn-cuo is here evaluated by the frog embyo teratogenesis assay-xenopus ... | 2015 | 25820130 |
| 17α-ethinylestradiol can disrupt hemoglobin catabolism in amphibians. | different chemical substances, which enter the environment due to anthropogenic influences, can affect the endocrine system and influence development and physiology of aquatic animals. one of these endocrine disrupting chemicals is the synthetic estrogen, 17α-ethinylestradiol (ee2), which is a main component of various oral contraceptives and demonstrably affects many different aquatic vertebrates at extremely low concentrations by feminization phenomena. the aim of the present study was to inve ... | 2015 | 25819740 |
| an in vivo screen to identify candidate neurogenic genes in the developing xenopus visual system. | neurogenesis in the brain of xenopus laevis continues throughout larval stages of development. we developed a 2-tier screen to identify candidate genes controlling neurogenesis in xenopus optic tectum in vivo. first, microarray and nanostring analyses were used to identify candidate genes that were differentially expressed in sox2-expressing neural progenitor cells or their neuronal progeny. then an in vivo, time-lapse imaging-based screen was used to test whether morpholinos against 34 candidat ... | 2015 | 25818835 |
| crystal structure of a xenopus laevis skin proto-type galectin, close to but distinct from galectin-1. | xenopus laevis (african clawed frog) has two types of proto-type galectins that are similar to mammalian galectin-1 in amino acid sequence. one type, comprising xgalectin-ia and -ib, is regarded as being equivalent to galectin-1, and the other type, comprising xgalectin-va and -vb, is expected to be a unique galectin subgroup. the latter is considerably abundant in frog skin; however, its biological function remains unclear. we determined the crystal structures of two proto-type galectins, xgale ... | 2015 | 25804418 |
| functional characterization of the 1,5-benzodiazepine clobazam and its major active metabolite n-desmethylclobazam at human gaba(a) receptors expressed in xenopus laevis oocytes. | the 1,5-benzodiazepine clobazam is indicated for the adjunctive treatment of seizures associated with lennox-gastaut syndrome in patients 2 years of age or older in the united states, and for treatment of anxiety and various forms of epilepsy elsewhere. clobazam has been reported to exhibit different in vivo adverse effects and addiction liability profile than the classic 1,4-benzodiazepines. in this study, it was investigated whether the in vitro pharmacological properties of clobazam and its m ... | 2015 | 25798598 |
| regeneration of xenopus laevis spinal cord requires sox2/3 expressing cells. | spinal cord regeneration is very inefficient in humans, causing paraplegia and quadriplegia. studying model organisms that can regenerate the spinal cord in response to injury could be useful for understanding the cellular and molecular mechanisms that explain why this process fails in humans. here, we use xenopus laevis as a model organism to study spinal cord repair. histological and functional analyses showed that larvae at pre-metamorphic stages restore anatomical continuity of the spinal co ... | 2015 | 25797152 |
| apoptosis and differentiation of xenopus tail-derived myoblasts by thyroid hormone. | the metamorphosis of anuran amphibians is induced by thyroid hormone (th). to study the molecular mechanisms underlying tail regression during metamorphosis, we established a cell line, xl-b4, from a xenopus laevis tadpole tail at a premetamorphic stage. the cells expressed myoblast markers and differentiated into myotubes in differentiation medium. xl-b4 cells expressing fluorescent proteins were transplanted into tadpole tails. at 5 days post-transplantation, fluorescence was observed in myotu ... | 2015 | 25791374 |
| ensemble-based virtual screening for cannabinoid-like potentiators of the human glycine receptor α1 for the treatment of pain. | the human glycine receptors (hglyrs) are chloride-selective ion channels that mediate inhibitory neurotransmission in the brain stem and spinal cord. they are also targets for compounds of potential use in analgesic therapies. here, we develop a strategy to discover analgesic drugs via structure-based virtual screening based on the recently published nmr structure of the hglyr-α1 transmembrane domain (pdb id: 2m6i ) and the critical role of residue s296 in hglyr-α1 potentiation by δ(9)-tetrahydr ... | 2015 | 25790278 |
| hdac1 regulates the proliferation of radial glial cells in the developing xenopus tectum. | in the developing central nervous system (cns), progenitor cells differentiate into progeny to form functional neural circuits. radial glial cells (rgs) are a transient progenitor cell type that is present during neurogenesis. it is thought that a combination of neural trophic factors, neurotransmitters and electrical activity regulates the proliferation and differentiation of rgs. however, it is less clear how epigenetic modulation changes rg proliferation. we sought to explore the effect of hi ... | 2015 | 25789466 |
| species-specific loss of sexual dimorphism in vocal effectors accompanies vocal simplification in african clawed frogs (xenopus). | phylogenetic studies can reveal patterns of evolutionary change, including the gain or loss of elaborate courtship traits in males. male african clawed frogs generally produce complex and rapid courtship vocalizations, whereas female calls are simple and slow. in a few species, however, male vocalizations are also simple and slow, suggesting loss of male-typical traits. here, we explore features of the male vocal organ that could contribute to loss in two species with simple, slow male calls. in ... | 2015 | 25788725 |
| ear manipulations reveal a critical period for survival and dendritic development at the single-cell level in mauthner neurons. | second-order sensory neurons are dependent on afferents from the sense organs during a critical period in development for their survival and differentiation. past research has mostly focused on whole populations of neurons, hampering progress in understanding the mechanisms underlying these critical phases. to move toward a better understanding of the molecular and cellular basis of afferent-dependent neuronal development, we developed a new model to study the effects of ear removal on a single ... | 2015 | 25787878 |
| a gustatory receptor tuned to d-fructose in antennal sensilla chaetica of helicoverpa armigera. | insect gustatory systems play important roles in food selection and feeding behaviors. in spite of the enormous progress in understanding gustation in drosophila, for other insects one of the key elements in gustatory signaling, the gustatory receptor (gr), is still elusive. in this study, we report that fructose elicits behavioral and physiological responses in helicoverpa armigera (harm) to fructose and identify the gustatory receptor for this sugar. using the proboscis extension reflex (per) ... | 2015 | 25784630 |
| papc mediates self/non-self-distinction during snail1-dependent tissue separation. | cleft-like boundaries represent a type of cell sorting boundary characterized by the presence of a physical gap between tissues. we studied the cleft-like ectoderm-mesoderm boundary in xenopus laevis and zebrafish gastrulae. we identified the transcription factor snail1 as being essential for tissue separation, showed that its expression in the mesoderm depends on noncanonical wnt signaling, and demonstrated that it enables paraxial protocadherin (papc) to promote tissue separation through two n ... | 2015 | 25778923 |
| unique gene expression profile of the proliferating xenopus tadpole tail blastema cells deciphered by rna-sequencing analysis. | organ regenerative ability depends on the animal species and the developmental stage. the molecular bases for variable organ regenerative ability, however, remain unknown. previous studies have identified genes preferentially expressed in the blastema tissues in various animals, but transcriptome analysis of the isolated proliferating blastema cells has not yet been reported. in the present study, we used rna-sequencing analysis to analyze the gene expression profile of isolated proliferating bl ... | 2015 | 25775398 |
| developmentally regulated post-translational modification of nucleoplasmin controls histone sequestration and deposition. | nucleoplasmin (npm) is an abundant histone chaperone in vertebrate oocytes and embryos. during embryogenesis, regulation of npm histone binding is critical for its function in storing and releasing maternal histones to establish and maintain the zygotic epigenome. here, we demonstrate that xenopus laevis npm post-translational modifications (ptms) specific to the oocyte and egg promote either histone deposition or sequestration, respectively. mass spectrometry and npm phosphomimetic mutations us ... | 2015 | 25772360 |
| endogenous gradients of resting potential instructively pattern embryonic neural tissue via notch signaling and regulation of proliferation. | biophysical forces play important roles throughout embryogenesis, but the roles of spatial differences in cellular resting potentials during large-scale brain morphogenesis remain unknown. here, we implicate endogenous bioelectricity as an instructive factor during brain patterning in xenopus laevis. early frog embryos exhibit a characteristic hyperpolarization of cells lining the neural tube; disruption of this spatial gradient of the transmembrane potential (vmem) diminishes or eliminates the ... | 2015 | 25762681 |
| proteomics analysis of xenopus laevis gonad tissue following chronic exposure to atrazine. | atrazine is the most commonly detected pesticide contaminant in ground and surface water. previous studies have shown that atrazine is an endocrine disruptor owing to its adverse effects on the male reproductive system in several vertebrates, but very few molecular mechanisms for these effects have been revealed. in the present study, xenopus laevis were exposed to 100 ppb of atrazine for 120 d, and then the isobaric tags for relative and absolute quantitation (itraq) technique was used to detec ... | 2015 | 25760937 |
| cloning of interleukin-10 from african clawed frog (xenopus tropicalis), with the finding of il-19/20 homologue in the il-10 locus. | interleukin-10 (il-10) is a pleiotropic cytokine that plays an important role in immune system. in the present study, the il-10 gene of african clawed frog (xenopus tropicalis) was first cloned, and its expression pattern and 3d structure were also analyzed. the frog il-10 mrna encoded 172 amino acids which possessed several conserved features found in il-10s from other species, including five-exon/four-intron genomic structure, conserved four cysteine residues, il-10 family motif, and six α-hel ... | 2015 | 25759841 |
| direct observation of ca(2+) -induced calmodulin conformational transitions in intact xenopus laevis oocytes by (19) f nmr spectroscopy. | the ca(2+) -mediated conformational transition of the protein calmodulin (cam) is essential to a variety of signal transduction pathways. whether the transition in living cells is similar to that observed in buffer is not known. here, we report the direct observation by (19) f nmr spectroscopy of the transition of the ca(2+) -free and -bound forms in xenopus laevis oocytes at different ca(2+) levels. we find that the ca(2+) -bound cam population increased greatly upon binding the target protein ... | 2015 | 25753548 |
| efficient retina formation requires suppression of both activin and bmp signaling pathways in pluripotent cells. | retina formation requires the correct spatiotemporal patterning of key regulatory factors. while it is known that repression of several signaling pathways lead to specification of retinal fates, addition of only noggin, a known bmp antagonist, can convert pluripotent xenopus laevis animal cap cells to functional retinal cells. the aim of this study is to determine the intracellular molecular events that occur during this conversion. surprisingly, blocking bmp signaling alone failed to mimic nogg ... | 2015 | 25750435 |
| phospholipase c and d regulation of src, calcium release and membrane fusion during xenopus laevis development. | this review emphasizes how lipids regulate membrane fusion and the proteins involved in three developmental stages: oocyte maturation to the fertilizable egg, fertilization and during first cleavage. decades of work show that phosphatidic acid (pa) releases intracellular calcium, and recent work shows that the lipid can activate src tyrosine kinase or phospholipase c during xenopus fertilization. numerous reports are summarized to show three levels of increase in lipid second messengers inositol ... | 2015 | 25748412 |
| more similar than you think: frog metamorphosis as a model of human perinatal endocrinology. | hormonal control of development during the human perinatal period is critically important and complex with multiple hormones regulating fetal growth, brain development, and organ maturation in preparation for birth. genetic and environmental perturbations of such hormonal control may cause irreversible morphological and physiological impairments and may also predispose individuals to diseases of adulthood, including diabetes and cardiovascular disease. endocrine and molecular mechanisms that reg ... | 2015 | 25744725 |
| xenopus laevis oocytes as a model system for studying the interaction between asbestos fibres and cell membranes. | the mode of interaction of asbestos fibres with cell membranes is still debatable. one reason is the lack of a suitable and convenient cellular model to investigate the causes of asbestos toxicity. we studied the interaction of asbestos fibres with xenopus laevis oocytes, using electrophysiological and morphological methods. oocytes are large single cells, with a limited ability to endocytose molecular ligands; we therefore considered these cells to be a good model for investigating the nature o ... | 2015 | 25745069 |
| rns60, a charge-stabilized nanostructure saline alters xenopus laevis oocyte biophysical membrane properties by enhancing mitochondrial atp production. | we have examined the effects of rns60, a 0.9% saline containing charge-stabilized oxygen nanobubble-based structures. rns60 is generated by subjecting normal saline to taylor-couette-poiseuille (tcp) flow under elevated oxygen pressure. this study, implemented in xenopus laevis oocytes, addresses both the electrophysiological membrane properties and parallel biological processes in the cytoplasm. intracellular recordings from defolliculated x. laevis oocytes were implemented in: (1) air oxygenat ... | 2015 | 25742953 |
| manipulation and in vitro maturation of xenopus laevis oocytes, followed by intracytoplasmic sperm injection, to study embryonic development. | amphibian eggs have been widely used to study embryonic development. early embryonic development is driven by maternally stored factors accumulated during oogenesis. in order to study roles of such maternal factors in early embryonic development, it is desirable to manipulate their functions from the very beginning of embryonic development. conventional ways of gene interference are achieved by injection of antisense oligonucleotides (oligos) or mrna into fertilized eggs, enabling under- or over ... | 2015 | 25742326 |
| a regression-based differential expression detection algorithm for microarray studies with ultra-low sample size. | global gene expression analysis using microarrays and, more recently, rna-seq, has allowed investigators to understand biological processes at a system level. however, the identification of differentially expressed genes in experiments with small sample size, high dimensionality, and high variance remains challenging, limiting the usability of these tens of thousands of publicly available, and possibly many more unpublished, gene expression datasets. we propose a novel variable selection algorit ... | 2015 | 25738861 |
| allosteric modulation of the glycine receptor activated by agonists differing in efficacy. | the glycine receptor (glyr) is the predominant inhibitory neurotransmitter receptor in the brainstem and spinal cord but is also found in higher brain regions. glyr function is affected by a variety of allosteric modulators including drugs of abuse, such as ethanol and inhalants and the ubiquitous divalent cation zinc. two-electrode voltage-clamp experiments were conducted on xenopus laevis oocytes expressing wild-type α1 homomeric glycine receptors to compare the degree of enhancement produced ... | 2015 | 25721789 |
| [on a contribution of boris balinsky to the comparative and ecological embryology of amphibians]. | the outstanding embryologist boris ivanovich balinsky (1905-1997) worked in the soviet union up to 1941 and in south africa since 1949. his experimental studies fulfilled during the soviet period of his scientific career mainly on the embryos of the caudate amphibians are widely known. after moving to africa (johannesburg), he continued the research of amphibian development, with using those possibilities, which were offered by the diverse fauna of local anura. other embryologists started comple ... | 2015 | 25720271 |
| ferritin h subunit gene is specifically expressed in melanophore precursor-derived white pigment cells in which reflecting platelets are formed from stage ii melanosomes in the periodic albino mutant of xenopus laevis. | "white pigment cells" are derived from melanophore precursors and contain both melanophore-specific and iridophore-specific pigment organelles. whereas melanophores differentiate in the wild type regenerating tail, white pigment cells appear in the regenerating tail in the periodic albino mutant (a(p)/a(p)) of xenopus laevis. the localization and density of white pigment cells in the mutant regenerating tail are similar to those of melanophores in the wild type regenerating tail. here, white pig ... | 2015 | 25715760 |
| histone titration against the genome sets the dna-to-cytoplasm threshold for the xenopus midblastula transition. | during early development, animal embryos depend on maternally deposited rna until zygotic genes become transcriptionally active. before this maternal-to-zygotic transition, many species execute rapid and synchronous cell divisions without growth phases or cell cycle checkpoints. the coordinated onset of transcription, cell cycle lengthening, and cell cycle checkpoints comprise the midblastula transition (mbt). a long-standing model in the frog, xenopus laevis, posits that mbt timing is controlle ... | 2015 | 25713373 |
| histone h2a and h4 n-terminal tails are positioned by the mep50 wd repeat protein for efficient methylation by the prmt5 arginine methyltransferase. | the protein arginine methyltransferase prmt5 is complexed with the wd repeat protein mep50 (also known as wdr77 or androgen coactivator p44) in vertebrates in a tetramer of heterodimers. mep50 is hypothesized to be required for protein substrate recruitment to the catalytic domain of prmt5. here we demonstrate that the cross-dimer mep50 is paired with its cognate prmt5 molecule to promote histone methylation. we employed qualitative methylation assays and a novel ultrasensitive continuous assay ... | 2015 | 25713080 |
| molecular mechanism of chrdl1-mediated x-linked megalocornea in humans and in xenopus model. | chordin-like 1 (chrdl1) mutations cause non-syndromic x-linked megalocornea (xmc) characterized by enlarged anterior eye segments. mosaic corneal degeneration, presenile cataract and secondary glaucoma are associated with xmc. beside that chrdl1 encodes ventroptin, a secreted bone morphogenetic protein (bmp) antagonist, the molecular mechanism of xmc is not well understood yet. in a family with broad phenotypic variability of xmc, we identified the novel chrdl1 frameshift mutation c.807_808deltc ... | 2015 | 25712132 |
| valproate-induced neurodevelopmental deficits in xenopus laevis tadpoles. | autism spectrum disorder (asd) is increasingly thought to result from low-level deficits in synaptic development and neural circuit formation that cascade into more complex cognitive symptoms. however, the link between synaptic dysfunction and behavior is not well understood. by comparing the effects of abnormal circuit formation and behavioral outcomes across different species, it should be possible to pinpoint the conserved fundamental processes that result in disease. here we use a novel mode ... | 2015 | 25698756 |
| mismatch repair-dependent metabolism of o6-methylguanine-containing dna in xenopus laevis egg extracts. | the cytotoxicity of sn1-type alkylating agents such as n-methyl-n'-nitrosourea (mnu), n-methyl-n'-nitro-n-nitrosoguanidine (mnng), or the cancer chemotherapeutics temozolomide, dacarbazine and streptozotocin has been ascribed to the persistence of o(6)-methylguanine ((me)g) in genomic dna. one hypothesis posits that (me)g toxicity is caused by futile attempts of the mismatch repair (mmr) system to process (me)g/c or (me)g/t mispairs arising during replication, while an alternative proposal sugge ... | 2015 | 25697728 |
| monitoring of rhodopsin trafficking and mistrafficking in live photoreceptors. | outer segment (os) directed trafficking is required for accomplishing the extremely high concentration of rhodopsin and explicitly high photon sensitivity of rod photoreceptor cells. aberrant targeting of rhodopsin often leads to blinding disorders, due to various mechanisms causing rhodopsin mislocalization. until recently, it has been challenging to monitor the dynamics of rhodopsin biogenesis and trafficking. here, we describe a new method to visualize rhodopsin trafficking in living and unfi ... | 2015 | 25697531 |
| patterns of hypothalamic regionalization in amphibians and reptiles: common traits revealed by a genoarchitectonic approach. | most studies in mammals and birds have demonstrated common patterns of hypothalamic development highlighted by the combination of developmental regulatory genes (genoarchitecture), supporting the notion of the hypothalamus as a component of the secondary prosencephalon, topologically rostral to the diencephalon. in our comparative analysis we have summarized the data on the expression patterns of different transcription factors and neuroactive substances, used as anatomical markers, in the devel ... | 2015 | 25691860 |
| one-pot refolding of core histones from bacterial inclusion bodies allows rapid reconstitution of histone octamer. | we report an optimized method to purify and reconstitute histone octamer, which utilizes high expression of histones in inclusion bodies but eliminates the time consuming steps of individual histone purification. in the newly modified protocol, xenopus laevis h2a, h2b, h3, and h4 are expressed individually into inclusion bodies of bacteria, which are subsequently mixed together and denatured in 8m guanidine hydrochloride. histones are refolded and reconstituted into soluble octamer by dialysis a ... | 2015 | 25687285 |
| a functional correlate of severity in alternating hemiplegia of childhood. | mutations in atp1a3, the gene that encodes the α3 subunit of the na(+)/k(+) atpase, are the primary cause of alternating hemiplegia of childhood (ahc). correlations between different mutations and ahc severity were recently reported, with e815k identified in severe and d801n and g947r in milder cases. this study aims to explore the molecular pathological mechanisms in ahc and to identify functional correlates for mutations associated with different levels of disease severity. | 2015 | 25681536 |
| development of a new approach for targeted gene editing in primordial germ cells using talens in xenopus. | a gene of interest can be efficiently modified using transcription activator-like effector nucleases (talens) (christian et al., 2010;li et al., 2011). however, if a target gene is essential for development, growth and fertility, use of talens with high mutagenic activity in f0 frogs could result in developmental disorders or sterility, which would reduce the number of f1 progeny and make f1 phenotypical analysis difficult. we used the 3' untranslated region of deadsouth gene (ds-3') of xenopus ... | 2015 | 25661867 |
| histochemical analyses of biliary development during metamorphosis of xenopus laevis tadpoles. | in mammalian liver development, intrahepatic biliary morphogenesis takes place in periportal, but not in pericentral, regions. liver progenitor cells transiently form epithelial plate structures and then intrahepatic bile ducts around the portal veins under the influence of the mesenchyme. the present study was undertaken to histochemically examine normal biliary development and its dependence on the action of the thyroid hormone triiodothyronine (t3) in xenopus laevis tadpoles. in these tadpole ... | 2015 | 25660701 |
| microtubule-associated protein tau promotes neuronal class ii β-tubulin microtubule formation and axon elongation in embryonic xenopus laevis. | compared with its roles in neurodegeneration, much less is known about microtubule-associated protein tau's normal functions in vivo, especially during development. the external development and ease of manipulating gene expression of xenopus laevis embryos make them especially useful for studying gene function during early development. to study tau's functions in axon outgrowth, we characterized the most prominent tau isoforms of xenopus embryos and manipulated their expression. none of these fo ... | 2015 | 25656701 |
| cnrip1 is a regulator of eye and neural development in xenopus laevis. | cannabinoid receptor interacting protein 1 (cnrip1), which has been originally identified as the binding partner of cannabinoid receptor 1 (cnr1), is evolutionarily conserved throughout vertebrates, but its physiological function has been unknown. here, we identify a developmental role of cnrip1 using xenopus laevis embryos. during early embryogenesis, expression of xenopus laevis cnrip1 is highly restricted to the animal region of gastrulae where neural and eye induction occur, and afterward it ... | 2015 | 25652037 |
| understanding early organogenesis using a simplified in situ hybridization protocol in xenopus. | organogenesis is the study of how organs are specified and then acquire their specific shape and functions during development. the xenopuslaevis embryo is very useful for studying organogenesis because their large size makes them very suitable for identifying organs at the earliest steps in organogenesis. at this time, the primary method used for identifying a specific organ or primordium is whole mount in situ hybridization with labeled antisense rna probes specific to a gene that is expressed ... | 2015 | 25651461 |