| increased transcript levels and kinetic function of pyruvate kinase during severe dehydration in aestivating african clawed frogs, xenopus laevis. | the african clawed frog, xenopus laevis, can withstand extremely arid conditions through aestivation, resulting in dehydration and urea accumulation. aestivating x. laevis reduce their metabolic rate, and rely on anaerobic glycolysis to meet reduced atp demands. the present study investigated how severe dehydration affected the transcript levels, kinetic profile, and phosphorylation state of the key glycolytic enzyme pyruvate kinase (pk) in the liver and skeletal muscle of x. laevis. compared to ... | 0 | 29331521 |
| spinal cord cells from pre-metamorphic stages differentiate into neurons and promote axon growth and regeneration after transplantation into the injured spinal cord of non-regenerative xenopus laevis froglets. | mammals are unable to regenerate its spinal cord after a lesion, meanwhile, anuran amphibians are capable of spinal cord regeneration only as larvae, and during metamorphosis, this capability is lost. sox2/3+ cells present in the spinal cord of regenerative larvae are required for spinal cord regeneration. here we evaluate the effect of the transplantation of spinal cord cells from regenerative larvae into the resected spinal cord of non-regenerative stages (nr-stage). donor cells were able to s ... | 2017 | 29326551 |
| retinoic acid promotes stem cell differentiation and embryonic development by transcriptionally activating cftr. | retinoic acid (ra) plays a pivotal role in many cellular processes; however, the signaling mechanisms mediating the effect of ra are not fully understood. here, we show that ra transcriptionally upregulates cystic fibrosis transmembrane conductance regulator (cftr) by promoting the direct binding of its receptor rarα to cftr promoter in mouse spermatogonia and embryonic stem (es) cells. the ra/cftr pathway is involved in the differentiation of spermatogonia and organogenesis during the embryo de ... | 0 | 29326073 |
| bisphenol f disrupts thyroid hormone signaling and postembryonic development in xenopus laevis. | the safety of bisphenol a (bpa) alternatives has attracted much attention due to their wide use. in this study, we investigated the effects of bisphenol f (bpf), an alternative to bpa, on thyroid hormone (th) signaling and postembryonic development in vertebrates using t3-induced and spontaneous xenopus metamorphosis as models. we found that in the t3-induced metamorphosis assay, higher concentrations of bpf (100-10000 nm) antagonized t3-induced th-response gene transcription and morphological c ... | 0 | 29323886 |
| autocatalytic microtubule nucleation determines the size and mass of xenopus laevis egg extract spindles. | regulation of size and growth is a fundamental problem in biology. a prominent example is the formation of the mitotic spindle, where protein concentration gradients around chromosomes are thought to regulate spindle growth by controlling microtubule nucleation. previous evidence suggests that microtubules nucleate throughout the spindle structure. however, the mechanisms underlying microtubule nucleation and its spatial regulation are still unclear. here, we developed an assay based on laser ab ... | 0 | 29323637 |
| reference gene identification and validation for quantitative real-time pcr studies in developing xenopus laevis. | reference genes are essential for gene expression analysis when using real-time quantitative pcr (rt-qpcr). xenopus laevis is a popular amphibian model for studying vertebrate embryogenesis and development. further, x. laevis is ideal for studying thyroid signaling due to its thyroid dependent metamorphosis, a stage comparable to birth in humans. when using pcr based studies, a primary concern is the choice of reference genes. commonly used references are eef1a1, odc1, rpl8, and actnb, although ... | 0 | 29323148 |
| cranial neural crest transplants. | the transplantation of cranial neural crest (cnc) expressing green fluorescent protein (gfp) in xenopus laevis has allowed researchers not only to assess cnc migration in vivo but also to address many other experimental questions. coupled with loss- or gain-of-function experiments, this technique can be used to characterize the function of specific genes during cnc migration and differentiation. although targeted injection can also be used to assess gene function during cnc migration, cnc transp ... | 0 | 29321285 |
| cranial neural crest explants. | the cranial neural crest (cnc) explant assay was originally designed to assess the basic requirements for cnc migration in vitro. this protocol describes the key parameters of cnc explants in xenopus laevis, with a focus on how to extirpate cnc cells and assay their migration in vitro. the protocol can be adapted according to the needs of the experimenter, some examples of which are discussed here. | 0 | 29321283 |
| nucleus assembly and import in xenopus laevis egg extract. | xenopus egg extract represents a powerful cell-free biochemical tool for studying organelle assembly and function. large quantities of cytoplasm can be isolated, and biochemical manipulation of extract composition and cell cycle state is relatively straightforward. in this protocol, we describe the reconstitution of nuclear assembly by adding a chromatin source to interphasic x. laevis egg extract. intact nuclei assemble within 30-45 min of initiating the reaction, followed by nuclear growth. we ... | 0 | 29321282 |
| analysis of mitotic checkpoint function in xenopus egg extracts. | accurate sister chromatid segregation is pivotal in the faithful transmission of genetic information during each cell division. to ensure accurate segregation, eukaryotic organisms have evolved a "mitotic (or spindle assembly) checkpoint" to prevent premature advance to anaphase before successful attachment of every chromosome to the microtubules of the mitotic spindle. an unattached kinetochore generates a diffusible signal that inhibits ubiquitination of substrates such as cyclin b and securin ... | 0 | 29321280 |
| whole-mount immunofluorescence for visualizing endogenous protein and injected rna in xenopus oocytes. | asymmetric distribution of mrna and protein is a hallmark of cell polarity in many systems. the xenopus laevis oocyte provides many technical advantages to studying such polarity. thousands of oocytes at different stages of maturity can be harvested from a single ovary and, owing to their relatively large size, even the youngest oocytes can be manually microinjected. microinjection of fluorescently labeled rna combined with immunofluorescence of endogenous proteins can provide insight into the c ... | 0 | 29321279 |
| paternal chromosome loss and metabolic crisis contribute to hybrid inviability in xenopus. | hybridization of eggs and sperm from closely related species can give rise to genetic diversity, or can lead to embryo inviability owing to incompatibility. although central to evolution, the cellular and molecular mechanisms underlying post-zygotic barriers that drive reproductive isolation and speciation remain largely unknown. species of the african clawed frog xenopus provide an ideal system to study hybridization and genome evolution. xenopus laevis is an allotetraploid with 36 chromosomes ... | 0 | 29320479 |
| molecular determinants of α3β4 nicotinic acetylcholine receptors inhibition by triterpenoids. | in a previous work, we reported the regulatory role of the triterpenoids on 5-hydroxytryptamine (5-ht)3a receptors activity in xenopus laevis oocytes (eur. j. pharmacol., 615, 2009, lee et al.). in the present report, we studied the modulation of triterpenoids on the activity of the human nicotinic acetylcholine receptor type α3β4. two-electrode voltage clamp experiments were used to test acetylcholine mediated inward current (iach). treatment with triterpenoids (dehydroeburicoic acid, 6α-hydrox ... | 0 | 29311484 |
| exploring the underlying mechanisms of xenopus laevis embryonic cell cycle. | cell cycle is an indispensable process in the proliferation and development. despite significant efforts, global quantification and physical understanding are still challenging. in this study, we explored the mechanisms of xenopus laevis embryonic cell cycle by quantifying the underlying landscape and flux. we uncovered the mexican hat landscape of the xenopus laevis embryonic cell cycle with several local basins and barriers on the oscillation path. the local basins characterize the different p ... | 0 | 29310435 |
| a glyphosate micro-emulsion formulation displays teratogenicity in xenopus laevis. | glyphosate is the active ingredient in broad-spectrum herbicide formulations used in agriculture, domestic area and aquatic weed control worldwide. its market is growing steadily concurrently with the cultivation of glyphosate-tolerant transgenic crops and emergence of weeds less sensitive to glyphosate. ephemeral and lentic waters near to agricultural lands, representing favorite habitats for amphibian reproduction and early life-stage development, may thus be contaminated by glyphosate based h ... | 2017 | 29306033 |
| bioelectric regulation of innate immune system function in regenerating and intact xenopus laevis. | two key inputs that regulate regeneration are the function of the immune system, and spatial gradients of transmembrane potential (vmem). endogenous bioelectric signaling in somatic tissues during regenerative patterning is beginning to be understood, but its role in the context of immune response has never been investigated. here, we show that vmem levels modulate innate immunity activity in xenopus laevis embryos. we developed an assay in which x. laevis embryos are infected with a uropathogen ... | 2017 | 29302351 |
| a triad of residues is functionally transferrable between 5-ht3 serotonin receptors and nicotinic acetylcholine receptors. | cys-loop receptors are pentameric ligand-gated ion channels that facilitate communication within the nervous system. upon neurotransmitter binding, these receptors undergo an allosteric activation mechanism connecting the binding event to the membrane-spanning channel pore, which expands to conduct ions. some of the earliest steps in this activation mechanism are carried out by residues proximal to the binding site, the relative positioning of which may reflect functional differences among membe ... | 0 | 29298898 |
| dioxin exposure alters molecular and morphological responses to thyroid hormone in xenopus laevis cultured cells and prometamorphic tadpoles. | amphibian metamorphosis is driven by thyroid hormone (th). we used prometamorphic tadpoles and a cell line of the african clawed frog (xenopus laevis) to examine immediate effects of dioxin exposure on th. gene expression patterns suggest cross-talk between the thyroid hormone receptor (tr) and aryl hydrocarbon receptor (ahr) signaling pathways. in xlk-wg cells, expression of cytochrome p450 1a6 (cyp1a6), an ahr target, was induced 1000-fold by 100 nm tcdd (2, 3, 7, 8 tetrachlorodibenzo-p-dioxin ... | 0 | 29294139 |
| a transgenic reporter under control of an es1 promoter/enhancer marks wound epidermis and apical epithelial cap during tail regeneration in xenopus laevis tadpole. | rapid wound healing and subsequent formation of the apical epithelial cap (aec) are believed to be required for successful appendage regeneration in amphibians. despite the significant role of aec in limb regeneration, its role in tail regeneration and the mechanisms that regulate the wound healing and aec formation are not well understood. we previously identified xenopus laevis es1, which is preferentially expressed in wounded regions, including the aec after tail regeneration. in this study w ... | 0 | 29291984 |
| hyperinnervation improves xenopus laevis limb regeneration. | xenopus laevis (an anuran amphibian) shows limb regeneration ability between that of urodele amphibians and that of amniotes. xenopus frogs can initiate limb regeneration but fail to form patterned limbs. regenerated limbs mainly consist of cone-shaped cartilage without any joints or branches. these pattern defects are thought to be caused by loss of proper expressions of patterning-related genes. this study shows that hyperinnervation surgery resulted in the induction of a branching regenerate. ... | 0 | 29291977 |
| optimization of mass spectrometric parameters improve the identification performance of capillary zone electrophoresis for single-shot bottom-up proteomics analysis. | the effects of ms1 injection time, ms2 injection time, dynamic exclusion time, intensity threshold, and isolation width were investigated on the numbers of peptide and protein identifications for single-shot bottom-up proteomics analysis using cze-ms/ms analysis of a xenopus laevis tryptic digest. an electrokinetically pumped nanospray interface was used to couple a linear-polyacrylamide coated capillary to a q exactive hf mass spectrometer. a sensitive method that used a 1.4 th isolation width, ... | 0 | 29291811 |
| microprobe capillary electrophoresis mass spectrometry for single-cell metabolomics in live frog (xenopus laevis) embryos. | the quantification of small molecules in single cells raises new potentials for better understanding the basic processes that underlie embryonic development. to enable single-cell investigations directly in live embryos, new analytical approaches are needed, particularly those that are sensitive, selective, quantitative, robust, and scalable to different cell sizes. here, we present a protocol that enables the in situ analysis of metabolism in single cells in freely developing embryos of the sou ... | 2017 | 29286491 |
| nanoscale correlated disorder in out-of-equilibrium myelin ultrastructure. | ultrastructural fluctuations at nanoscale are fundamental to assess properties and functionalities of advanced out-of-equilibrium materials. we have taken myelin as a model of supramolecular assembly in out-of-equilibrium living matter. myelin sheath is a simple stable multilamellar structure of high relevance and impact in biomedicine. although it is known that myelin has a quasi-crystalline ultrastructure, there is no information on its fluctuations at nanoscale in different states due to limi ... | 0 | 29281257 |
| proton-independent activation of acid-sensing ion channel asic3 by alkaloid lindoldhamine from laurus nobilis. | acid-sensing ion channels (asics) play an important role in synaptic plasticity and learning, as well as in nociception and mechanosensation. asics are implicated in pain, neurological and psychiatric diseases but their therapeutic potential is limited by lack of ligands activating them at physiological ph. | 2017 | 29277899 |
| direct modification of the 5-ht3 receptor current by some anticancer drugs. | the serotonin (5-hydroxytryptamine) type 3 (5-ht3) receptor is an important target in the control of emesis, and 5-ht3 receptor antagonists are effective against the early phase chemotherapy evoked vomiting. we recently reported that the anticancer drugs irinotecan and topotecan directly modulate the 5-ht-mediated 5-ht3 receptor current in vitro. in addition, the drug response depends on the 5-ht3 subunit composition. here, we explored the effects of 35 anticancer drugs on the 5-ht3 receptor cur ... | 2017 | 29277715 |
| anosmin-1 is essential for neural crest and cranial placodes formation in xenopus. | during embryogenesis vertebrates develop a complex craniofacial skeleton associated with sensory organs. these structures are primarily derived from two embryonic cell populations the neural crest and cranial placodes, respectively. neural crest cells and cranial placodes are specified through the integrated action of several families of signaling molecules, and the subsequent activation of a complex network of transcription factors. here we describe the expression and function of anosmin-1 (ano ... | 0 | 29277616 |
| the progestin norethisterone affects thyroid hormone-dependent metamorphosis of xenopus laevis tadpoles at environmentally relevant concentrations. | previously, levonorgestrel (lng) has been shown to be an endocrine disruptor of the amphibian thyroid system. in the present study, we investigated whether anti-thyroidal effects are a common property of progestins other than lng. premetamorphic xenopus laevis tadpoles were exposed to norethisterone (net) and dienogest die (each at 0.1-10nm) and lng (10nm) until completion of metamorphosis. lng and net at all concentrations caused a significant developmental retardation whereas die did not impai ... | 0 | 29268119 |
| rna helicase mov10 is essential for gastrulation and cns development. | mov10 is an rna helicase that modulates access of argonaute 2 to microrna recognition elements in mrnas. we examined the role of mov10 in xenopus laevis development and show a critical role for mov10 in gastrulation and in the development of the central nervous system. | 2017 | 29266590 |
| dynamic intramolecular regulation of the histone chaperone nucleoplasmin controls histone binding and release. | nucleoplasmin (npm) is a highly conserved histone chaperone responsible for the maternal storage and zygotic release of histones h2a/h2b. npm contains a pentameric n-terminal core domain and an intrinsically disordered c-terminal tail domain. though intrinsically disordered regions are common among histone chaperones, their roles in histone binding and chaperoning remain unclear. using an nmr-based approach, here we demonstrate that the xenopus laevis npm tail domain controls the binding of hist ... | 2017 | 29263320 |
| differentiation-dependent antiviral capacities of amphibian (xenopus laevis) macrophages. | infections by ranaviruses such as frog virus 3 (fv3) are significantly contributing to the worldwide amphibian population declines. notably, amphibian macrophages (mφs) are important to both the fv3 infection strategies and the immune defense against this pathogen. however, the mechanisms underlying amphibian mφ fv3 susceptibility and resistance remain unknown. mφ differentiation is mediated by signaling through the colony-stimulating factor-1 receptor (csf-1r), which is now known to be bound by ... | 2017 | 29259133 |
| tight junctions negatively regulate mechanical forces applied to adherens junctions in vertebrate epithelial tissue. | epithelia are layers of polarised cells tightly bound to each other by adhesive contacts. epithelia act as barriers between an organism and its external environment. understanding how epithelia maintain their essential integrity while remaining sufficiently plastic to allow events such as cytokinesis to take place is a key biological problem. in vertebrates, the remodelling and reinforcement of adherens junctions maintains epithelial integrity during cytokinesis. the involvement of tight junctio ... | 2017 | 29246943 |
| unravelling the mechanisms that determine the uptake and metabolism of magnetic single and multicore nanoparticles in a xenopus laevis model. | multicore superparamagnetic nanoparticles have been proposed as ideal tools for some biomedical applications because of their high magnetic moment per particle, high specific surface area and long term colloidal stability. through controlled aggregation and packing of magnetic cores it is possible to obtain not only single-core but also multicore and hollow spheres with internal voids. in this work, we compare toxicological properties of single and multicore nanoparticles. both types of particle ... | 0 | 29242877 |
| rnas coordinate nuclear envelope assembly and dna replication through elys recruitment to chromatin. | upon fertilisation, the sperm pronucleus acquires the competence to replicate the genome through a cascade of events that link chromatin remodelling to nuclear envelope formation. the factors involved have been partially identified and are poorly characterised. here, using xenopus laevis egg extracts we show that rnas are required for proper nuclear envelope assembly following sperm dna decondensation. although chromatin remodelling and pre-replication complex formation occur normally, rna-deple ... | 2017 | 29242643 |
| functional reintegration of sensory neurons and transitional dendritic reduction of mitral/tufted cells during injury-induced recovery of the larval xenopus olfactory circuit. | understanding the mechanisms involved in maintaining lifelong neurogenesis has a clear biological and clinical interest. in the present study, we performed olfactory nerve transection on larval xenopus to induce severe damage to the olfactory circuitry. we surveyed the timing of the degeneration, subsequent rewiring and functional regeneration of the olfactory system following injury. a range of structural labeling techniques and functional calcium imaging were performed on both tissue slices an ... | 2017 | 29234276 |
| the human dna glycosylases neil1 and neil3 excise psoralen-induced dna-dna cross-links in a four-stranded dna structure. | interstrand cross-links (icls) are highly cytotoxic dna lesions that block dna replication and transcription by preventing strand separation. previously, we demonstrated that the bacterial and human dna glycosylases nei and neil1 excise unhooked psoralen-derived icls in three-stranded dna via hydrolysis of the glycosidic bond between the crosslinked base and deoxyribose sugar. furthermore, neil3 from xenopus laevis has been shown to cleave psoralen- and abasic site-induced icls in xenopus egg ex ... | 2017 | 29234069 |
| antagonistic effect of dopamine structural analogues on human gabaρ1 receptor. | gabaergic and dopaminergic pathways are co-localized in several areas of the central nervous system and recently several reports have shown co-release of both neurotransmitters. the gaba-a receptor (β and ρ1 subunits) is modulated by dopamine (da) and, interestingly, gabaρ1 can be modulated by several biogenic amines. here we explored the effects of the metabolites of the dopaminergic pathway and other structural analogues of da on gabaρ1 and the da gated ion channel (lgc-53) from caenorhabditis ... | 2017 | 29234054 |
| increasing the length and hydrophobicity of the c-terminal sequence of transthyretin strengthens its binding affinity to retinol binding protein. | transthyretin (ttr) is a transporter for thyroid hormone (th) and retinol, the latter via binding with retinol binding protein (rbp). both the n-terminal and c-terminal regions of the ttr subunit are located in close proximity to the central binding channel for ligands. during the evolution of vertebrates, these regions changed in length and hydropathy. the changes in the n-terminal sequence were demonstrated to affect the binding affinities for ths and rbp. here, the effects of changes in the c ... | 2017 | 29226076 |
| species specific rna a-to-i editing of mosquito rdl modulates gaba potency and influences agonistic, potentiating and antagonistic actions of ivermectin. | the insect gaba receptor, rdl, is the target of several classes of pesticides. the peptide sequences of rdl are generally highly conserved between diverse insects. however, rna a-to-i editing can effectively alter amino acid residues of rdl in a species specific manner, which can affect the potency of gaba and possibly insecticides. we report here that rna a-to-i editing alters the gene products of rdl in three mosquito disease vectors, recoding five amino acid residues in rdl of aedes aegypti a ... | 2017 | 29223796 |
| glut characterization using frog xenopus laevis oocytes. | xenopus laevis oocytes are a useful heterologous expression system for expressing glucose transporters (gluts) and examining their functions. in this chapter, we provide a detailed protocol on oocyte extraction and preparation for glut9 protein expression. furthermore, we describe the determination of glut9 overexpression level by biotinylation and western blotting analysis. finally, we also describe how glut9-expressing oocytes can be used to measure urate kinetics by radioisotopes as well as t ... | 0 | 29218516 |
| xenopus laevis as a model organism for the study of spinal cord formation, development, function and regeneration. | the spinal cord is the first central nervous system structure to develop during vertebrate embryogenesis, underscoring its importance to the organism. because of its early formation, accessibility to the developing spinal cord in amniotes is challenging, often invasive and the experimental approaches amenable to model systems like mammals are limited. in contrast, amphibians, in general and the african-clawed frog xenopus laevis, in particular, offer model systems in which the formation of the s ... | 2017 | 29218002 |
| interaction of purinergic p2x4 and p2x7 receptor subunits. | p2x4 and p2x7 are members of the p2x receptor family, comprising seven isoforms (p2x1-p2x7) that form homo- and heterotrimeric non-specific cation channels gated by extracellular atp. p2x4 and p2x7 are widely coexpressed, particularly in secretory epithelial cells and immune and inflammatory cells, and regulate inflammation and nociception. although functional heteromerization has been established for p2x2 and p2x3 subunits expressed in sensory neurons, there are contradictory reports regarding ... | 2017 | 29213241 |
| spindle-to-cortex communication in cleaving frog eggs. | during cytokinesis, the mitotic spindle communicates with the cell cortex to position a cleavage furrow that will cut through the cell in the plane defined by the metaphase plate. we investigated the molecular basis of this communication in xenopus laevis eggs, where the signal has to travel ∼400 µm in ∼30 min to reach the cortex from the first anaphase spindle. at anaphase onset, huge microtubule asters grow out from the poles of the spindle and meet at the plane previously defined by the metap ... | 2017 | 29196560 |
| the ectodomain of cadherin-11 binds to erbb2 and stimulates akt phosphorylation to promote cranial neural crest cell migration. | during development, a multi-potent group of cells known as the cranial neural crest (cnc) migrate to form craniofacial structures. proper migration of these cells requires proteolysis of cell adhesion molecules, such as cadherins. in xenopus laevis, preventing extracellular cleavage of cadherin-11 impairs cnc migration. however, overexpression of the soluble cleavage product (ec1-3) is capable of rescuing this phenotype. the mechanism by which ec1-3 promotes cnc migration has not been investigat ... | 2017 | 29190819 |
| tissue-specific gene inactivation in xenopus laevis: knockout of lhx1 in the kidney with crispr/cas9. | studying genes involved in organogenesis is often difficult because many of these genes are also essential for early development. the allotetraploid frog, xenopus laevis, is commonly used to study developmental processes, but because of the presence of two homeologs for many genes, it has been difficult to use as a genetic model. few studies have successfully used crispr in amphibians, and currently there is no tissue-targeted knockout strategy described in xenopus the goal of this study is to d ... | 2017 | 29187504 |
| evaluating the longevity of surgically extracted xenopus laevis oocytes for the study of nematode ligand-gated ion channels. | xenopus laevis oocytes have been extensively used as a heterologous expression system for the study of ion channels. while used successfully worldwide as tool for expressing and characterizing ion channels from a wide range of species, the limited longevity of oocytes once removed from the animal can pose significant challenges. in this study, we evaluate a simple and useful method that extends the longevity of xenopus oocytes after removal from the animal and quantitatively assessed the reliabi ... | 2017 | 29185074 |
| quantification of size effect on protein rotational mobility in cells by 19f nmr spectroscopy. | protein diffusion in living cells might differ significantly from that measured in vitro. little is known about the effect of globular protein size on rotational diffusion in cells because each protein has distinct surface properties, which result in different interactions with cellular components. to overcome this problem, the b1 domain of protein g (gb1) and several concatemers of the protein were labeled with 5-fluorotryptophan and studied by 19f nmr in escherichia coli cells, xenopus laevis ... | 2017 | 29184995 |
| the r81t mutation in the nicotinic acetylcholine receptor of aphis gossypii is associated with neonicotinoid insecticide resistance with differential effects for cyano- and nitro-substituted neonicotinoids. | the cotton aphid, aphis gossypii glover, is one of the most agriculturally important insect pests. neonicotinoid insecticides and sulfoxaflor have generally shown excellent control of a. gossypii, but these aphids have recently developed resistance against neonicotinoid insecticides. we previously characterized a field-collected a. gossypii kushima clone that showed higher resistance to nitro-substituted neonicotinoids, such as imidacloprid, than to cyano-substituted neonicotinoids, such as acet ... | 2017 | 29183611 |
| targeted base editing via rna-guided cytidine deaminases in xenopus laevis embryos. | genome editing using programmable nucleases such as crispr/cas9 or cpf1 has emerged as powerful tools for gene knock-out or knock-in in various organisms. while most genetic diseases are caused by point mutations, these genome-editing approaches are inefficient in inducing single-nucleotide substitutions. recently, cas9-linked cytidine deaminases, named base editors (bes), have been shown to convert cytidine to uridine efficiently, leading to targeted single-base pair substitutions in human cell ... | 2017 | 29179261 |
| effect of imidacloprid on the survival of xenopus tadpoles challenged with wild type frog virus 3. | the sensitivity of amphibians to ranavirus may be increased by exposure to other environmental stressors, including chemical contaminants. neonicotinoid insecticides comprise 27% of the global insecticide market and have been detected in wetlands and other aquatic habitats. the present study focused on the effects of exposure of pre-metamorphic xenopus laevis to the neonicotinoid, imidacloprid (imi) on sensitivity to frog virus 3 (fv3) infection. it was hypothesized that exposure of tadpoles to ... | 0 | 29179150 |
| regulation of kv1.4 potassium channels by pkc and ampk kinases. | over the last years extensive kinase-mediated regulation of a number of voltage-gated potassium (kv) channels important in cardiac electrophysiology has been reported. this includes regulation of kv1.5, kv7.1 and kv11.1 cell surface expression, where the kinase-mediated regulation appears to center around the ubiquitin ligase nedd4-2. in the present study we examined whether kv1.4, constituting the cardiac ito,s current, is subject to similar regulation. in the epithelial madin-darby canine kidn ... | 0 | 29168928 |
| identification of isthmin 1 as a novel clefting and craniofacial patterning gene in humans. | orofacial clefts are one of the most common birth defects, affecting 1-2 per 1000 births, and have a complex etiology. high-resolution array-based comparative genomic hybridization has increased the ability to detect copy number variants (cnvs) that can be causative for complex diseases such as cleft lip and/or palate. utilizing this technique on 97 nonsyndromic cleft lip and palate cases and 43 cases with cleft palate only, we identified a heterozygous deletion of isthmin 1 in one affected case ... | 0 | 29162626 |
| functional differences in transport properties of natural hkt1;1 variants influence shoot na+ exclusion in grapevine rootstocks. | under salinity, vitis spp. rootstocks can mediate salt (nacl) exclusion from grafted v. vinifera scions enabling higher grapevine yields and production of superior wines with lower salt content. until now, the genetic and mechanistic elements controlling sodium (na+ ) exclusion in grapevine were unknown. using a cross between two vitis interspecific hybrid rootstocks, we mapped a dominant quantitative trait locus (qtl) associated with leaf na+ exclusion (nae) under salinity stress. the nae locus ... | 0 | 29160564 |
| 4-aminopyridine: a pan voltage-gated potassium channel inhibitor that enhances kv 7.4 currents and inhibits noradrenaline-mediated contraction of rat mesenteric small arteries. | kv 7.4 and kv 7.5 channels are regulators of vascular tone. 4-aminopyridine (4-ap) is considered a broad inhibitor of voltage-gated potassium (kv ) channels, with little inhibitory effect on kv 7 family members at mmol concentrations. however, the effect of 4-ap on kv 7 channels has not been systematically studied. the aim of this study was to investigate the pharmacological activity of 4-ap on kv 7.4 and kv 7.5 channels and characterize the effect of 4-ap on rat resistance arteries. | 2017 | 29156097 |
| functional properties and mechanism of action of pptq, an allosteric agonist and low nanomolar positive allosteric modulator at gabaa receptors. | the former sedative-hypnotic and recreational drug methaqualone (quaalude) is a moderately potent, non-selective positive allosteric modulator (pam) at gabaa receptors (gabaars) (hammer et al., 2015). in the present study, we have identified a novel methaqualone analog, 2-phenyl-3-(p-tolyl)quinazolin-4(3h)-one (pptq), in a screening of 67 analogs at five αβ2γ2s gabaar subtypes and delineated its functional properties and mechanism of action at wild-type and mutant gabaars expressed in xenopus la ... | 0 | 29155148 |
| a nonredundant role for the trpm6 channel in neural tube closure. | in humans, germline mutations in trpm6 cause autosomal dominant hypomagnesemia with secondary hypocalcemia disorder. loss of trpm6 in mice also perturbs cellular magnesium homeostasis but additionally results in early embryonic lethality and neural tube closure defects. to define the mechanisms by which trpm6 influences neural tube closure, we functionally characterized the role of trpm6 during early embryogenesis in xenopus laevis. the expression of xenopus trpm6 (xtrpm6) is elevated at the ons ... | 2017 | 29142255 |
| developmental changes in spinal neuronal properties, motor network configuration and neuromodulation at free-swimming stages of xenopus frog tadpoles. | we describe a novel preparation of the isolated brainstem and spinal cord from pro-metamorphic tadpole stages of the south african clawed frog (xenopus laevis) that permits whole cell patch-clamp recordings from neurons in the ventral spinal cord. previous research on earlier stages of the same species has provided one of the most detailed understandings of the design and operation of a cpg circuit. here we have addressed how development sculpts complexity from this more basic circuit. the prepa ... | 2017 | 29142093 |
| it's not all black and white: visual scene parameters influence optokinetic reflex performance in xenopus laevis tadpoles. | the maintenance of visual acuity during active and passive body motion is ensured by gaze-stabilizing reflexes that aim at minimizing retinal image slip. for the optokinetic reflex (okr), large-field visual motion of the surround forms the essential stimulus that activates eye movements. properties of the moving visual world influence cognitive motion perception and the estimation of visual image velocity. therefore, the performance of brainstem-mediated visuo-motor behaviors might also depend o ... | 2017 | 29141881 |
| overland movement in african clawed frogs (xenopus laevis): empirical dispersal data from within their native range. | dispersal forms are an important component of the ecology of many animals, and reach particular importance for predicting ranges of invasive species. african clawed frogs (xenopus laevis) move overland between water bodies, but all empirical studies are from invasive populations with none from their native southern africa. here we report on incidents of overland movement found through a capture-recapture study carried out over a three year period in overstrand, south africa. the maximum distance ... | 2017 | 29134157 |
| specific inhibition of gpcr-independent g protein signaling by a rationally engineered protein. | activation of heterotrimeric g proteins by cytoplasmic nonreceptor proteins is an alternative to the classical mechanism via g protein-coupled receptors (gpcrs). a subset of nonreceptor g protein activators is characterized by a conserved sequence named the gα-binding and activating (gba) motif, which confers guanine nucleotide exchange factor (gef) activity in vitro and promotes g protein-dependent signaling in cells. gba proteins have important roles in physiology and disease but remain greatl ... | 2017 | 29133411 |
| towards functional selectivity for α6β3γ2 gabaa receptors: a series of novel pyrazoloquinolinones. | the gabaa receptors are ligand-gated ion channels, which play an important role in neurotransmission. their variety of binding sites serves as an appealing target for many clinically relevant drugs. here, we explored the functional selectivity of modulatory effects at specific extracellular α+/β- interfaces, using a systematically varied series of pyrazoloquinolinones. | 2017 | 29127702 |
| wall following in xenopus laevis is barrier-driven. | the tendency of animals to follow boundaries within their environment can serve as a strategy for spatial learning or defensive behaviour. we examined whether xenopus laevis tadpoles and froglets employ such a strategy by characterizing their swimming pattern in a square tank with shallow water. trajectories obtained from video recordings were analysed for proximity to the nearest wall. with the exception of young larvae, the vast majority of animals (both tadpoles and froglets) spent a dispropo ... | 2017 | 29119247 |
| nuclear pore complex plasticity during developmental process as revealed by super-resolution microscopy. | nuclear pore complex (npc) is of paramount importance for cellular processes since it is the unique gateway for molecular exchange through the nucleus. unraveling the modifications of the npc structure in response to physiological cues, also called nuclear pore plasticity, is key to the understanding of the selectivity of this molecular machinery. as a step towards this goal, we use the optical super-resolution microscopy method called direct stochastic optical reconstruction microscopy (dstorm) ... | 2017 | 29116248 |
| the rice high-affinity k+ transporter oshkt2;4 mediates mg2+ homeostasis under high-mg2+ conditions in transgenic arabidopsis. | rice (oryza sativa; background nipponbare) contains nine hkt (high-affinity k+ transport)-like genes encoding membrane proteins belonging to the superfamily of ktr/trk/hkt. oshkts have been proposed to include four selectivity filter-pore-forming domains homologous to the bacterial k+ channel kcsa, and are separated into oshkt1s with na+-selective activity and oshkt2s with na+-k+ symport activity. as a member of the oshkt2 subfamily, oshkt2;4 renders mg2+ and ca2+ permeability for yeast cells an ... | 2017 | 29114257 |
| roles for xenopus aquaporin-3b (aqp3.l) during gastrulation: fibrillar fibronectin and tissue boundary establishment in the dorsal margin. | aquaporins and aquaglyceroporins are a large family of membrane channel proteins that allow rapid movement of water and small, uncharged solutes into and out of cells along concentration gradients. recently, aquaporins have been gaining recognition for more complex biological roles than the regulation of cellular osmotic homeostasis. we have identified a specific expression pattern for xenopus aqp3b (also called aqp3.l) during gastrulation, where it is localized to the sensorial (deep) layer of ... | 0 | 29113748 |
| biophysical characterization of genetically encoded voltage sensor asap1: dynamic range improvement. | recent work has introduced a new fluorescent voltage sensor, asap1, which can monitor rapid trains of action potentials in cultured neurons. this indicator is based on the gallus gallus voltage-sensitive phosphatase with the phosphatase domain removed and a circularly permuted gfp placed in the s3-s4 linker. however, many of the biophysical details of this indicator remain unknown. in this work, we study the biophysical properties of asap1. using the cut-open voltage clamp technique, we have sim ... | 2017 | 29108650 |
| influence of the rdl a301s mutation in the brown planthopper nilaparvata lugens on the activity of phenylpyrazole insecticides. | we discovered the a301s mutation in the rdl gaba-gated chloride channel of fiprole resistant rice brown planthopper, nilaparvata lugens populations by dna sequencing and snp calling via rnaseq. ethiprole selection of two field n. lugens populations resulted in strong resistance to both ethiprole and fipronil and resulted in fixation of the a301s mutation, as well as the emergence of another mutation, q359e in one of the selected strains. to analyse the roles of these mutations in resistance to p ... | 2017 | 29107231 |
| identification of novel cis-regulatory elements of eya1 in xenopus laevis using bac recombineering. | the multifunctional eya1 protein plays important roles during the development of cranial sensory organs and ganglia, kidneys, hypaxial muscles and several other organs in vertebrates. eya1 is encoded by a complex locus with candidate cis-regulatory elements distributed over a 329 kbp wide genomic region in xenopus. consequently, very little is currently known about how expression of eya1 is controlled by upstream regulators. here we use a library of xenopus tropicalis genomic sequences in bacter ... | 2017 | 29101371 |
| frizzled-7 is required for xenopus heart development. | wnt signalling regulates cardiogenesis during specification of heart tissue and the morphogenetic movements necessary to form the linear heart. wnt11-mediated non-canonical signalling promotes early cardiac development whilst wnt11-r, which is expressed later, also signals through the non-canonical pathway to promote heart development. it is unclear which frizzled proteins mediate these interactions. frizzled-7 (fzd7) is expressed during gastrulation in the mesodermal cells fated to become heart ... | 2017 | 29101100 |
| effect of isothiocyanates, bitc and peitc, on stress protein accumulation, protein aggregation and aggresome-like structure formation in xenopus a6 kidney epithelial cells. | numerous studies have elucidated the health benefits of organosulfur compounds, known as isothiocyanates (itcs), derived from cruciferous vegetables. as electrophiles, itcs have the ability to directly bind and modify thiol-containing compounds such as glutathione and cellular protein, including tubulin. while the biochemical effects of itcs have been well characterized, less information is available regarding their effects on the accumulation of stress-inducible heme oxygenase-1 (ho-1), heat sh ... | 0 | 29100952 |
| inheritance of histones h3 and h4 during dna replication in vitro. | nucleosomes are believed to carry epigenetic information through the cell cycle, including through dna replication. it has been known for decades that parental histones are reassembled on newly replicated chromatin, but the mechanisms underlying histone inheritance and dispersal during dna replication are not fully understood. we monitored the fate of histones h3 or h4 from a single nucleosome through dna replication in two in vitro systems. in the sv40 system, histones assembled on a single nuc ... | 2017 | 29091772 |
| abnormal creatine transport of mutations in monocarboxylate transporter 12 (mct12) found in patients with age-related cataract can be partially rescued by exogenous chaperone cd147. | membrane transporters influence biological functions in the ocular lens. here, we investigate the monocarboxylate transporter 12 (mct12), also called creatine transporter 2 (crt2), which is found in the ocular lens and is involved in cataract. as the age-related form affects about half of the population world-wide, understanding relevant pathomechanisms is a prerequisite for exploring non-invasive treatments. we screened the coding exons of the gene slc16a12 in 877 patients from five cohorts, in ... | 2017 | 29088427 |
| active site voltage clamp fluorometry of the sodium glucose cotransporter hsglt1. | in the human sodium glucose cotransporter (hsglt1) cycle, the protein undergoes conformational changes where the sugar-binding site alternatively faces the external and internal surfaces. functional site-directed fluorometry was used to probe the conformational changes at the sugar-binding site. residues (y290, t287, h83, and n78) were mutated to cysteines. the mutants were expressed in xenopus laevis oocytes and tagged with environmentally sensitive fluorescent rhodamines [e.g., tetramethylrhod ... | 2017 | 29087341 |
| elicitation of xenopus laevis tadpole and adult frog peritoneal leukocytes. | peritoneal lavage of xenopus laevis tadpoles and adult frogs is a reliable way of isolating resident and/or recruited innate immune populations. this protocol details the isolation of tadpole and adult amphibian (xenopus laevis) peritoneal leukocytes. the isolated cells are comprised predominantly of innate immune populations and chiefly of mononuclear and polymorphonuclear granulocytes. as described here, these cells are typically elicited by peritoneal injections of animals with heat-killed es ... | 2017 | 29084862 |
| bioconcentration and metabolism of pyriproxyfen in tadpoles of african clawed frogs, xenopus laevis. | bioconcentration and metabolism of pyriproxyfen uniformly labeled with 14c at the phenoxyphenyl ring were studied using tadpoles of african clawed frog, xenopus laevis, exposed to water at the nominal concentrations of 3 and 300 ppb for 22 days under the flow-through conditions, with a following 3 day depuration phase. neither meaningful mortality nor abnormal behavior was observed in control and exposure groups throughout the study. after the rapid uptake to tadpoles, pyriproxyfen was extensive ... | 2017 | 29084385 |
| development of xenopus laevis bipotential gonads into testis or ovary is driven by sex-specific cell-cell interactions, proliferation rate, cell migration and deposition of extracellular matrix. | information on the mechanisms orchestrating sexual differentiation of the bipotential gonads into testes or ovaries in amphibians is limited. the aim of this study was to investigate the development of xenopus laevis gonad, to identify the earliest signs of sexual differentiation, and to describe mechanisms driving these processes. we used light and electron microscopy, immunofluorescence and cell tracing. in order to identify the earliest signs of sexual differentiation the sex of each tadpole ... | 2017 | 29080791 |
| reactivation of larval keratin gene (krt62.l) in blastema epithelium during xenopus froglet limb regeneration. | limb regeneration is considered a form of limb redevelopment because of the molecular and morphological similarities. forming a regeneration blastema is, in essence, creating a developing limb bud in an adult body. this reactivation of a developmental process in a mature body is worth studying. xenopus laevis has a biphasic life cycle that involves distinct larval and adult stages. these distinct developmental stages are useful for investigating the reactivation of developmental processes in pos ... | 2017 | 29079423 |
| aurora a activation in mitosis promoted by bugz. | protein phase separation or coacervation has emerged as a potential mechanism to regulate biological functions. we have shown that coacervation of a mostly unstructured protein, bugz, promotes assembly of spindle and its matrix. bugz in the spindle matrix binds and concentrates tubulin to promote microtubule (mt) assembly. it remains unclear, however, whether bugz could regulate additional proteins to promote spindle assembly. in this study, we report that bugz promotes aurora a (aura) activatio ... | 0 | 29074706 |
| regulatory remodeling in the allo-tetraploid frog xenopus laevis. | genome duplication has played a pivotal role in the evolution of many eukaryotic lineages, including the vertebrates. a relatively recent vertebrate genome duplication is that in xenopus laevis, which resulted from the hybridization of two closely related species about 17 million years ago. however, little is known about the consequences of this duplication at the level of the genome, the epigenome, and gene expression. | 2017 | 29065907 |
| metabolic comparison of dorsal versus ventral cells directly in the live 8-cell frog embryo by microprobe single-cell ce-esi-ms. | single-cell mass spectrometry (ms) empowers the characterization of metabolomic changes as cells differentiate to different tissues during early embryogenesis. using whole-cell dissection and capillary electrophoresis electrospray ionization (ce-esi) ms, we recently uncovered metabolic cell-to-cell differences in the 8- and 16-cell embryo of the south african clawed frog (xenopus laevis), raising the question whether metabolic cell heterogeneity is also detectable across the dorsal-ventral axis ... | 2017 | 29062391 |
| xenbase: a genomic, epigenomic and transcriptomic model organism database. | xenbase (www.xenbase.org) is an online resource for researchers utilizing xenopus laevis and xenopus tropicalis, and for biomedical scientists seeking access to data generated with these model systems. content is aggregated from a variety of external resources and also generated by in-house curation of scientific literature and bioinformatic analyses. over the past two years many new types of content have been added along with new tools and functionalities to reflect the impact of high-throughpu ... | 0 | 29059324 |
| site-directed unnatural amino acid mutagenesis to investigate potassium channel pharmacology in xenopus laevis oocytes. | unnatural amino acid mutagenesis is a useful tool enabling detailed investigation of ion channel structure-function relationships and pharmacology. methods have been developed to apply this technique to different heterologous systems for electrophysiological studies, with each system offering unique advantages and limitations. synthesis of aminoacylated-trna followed by injection into xenopus laevis oocytes is beneficial because it allows for the incorporation of a wide range of unnatural sidech ... | 0 | 29058197 |
| interaction of excitatory amino acid transporters 1 - 3 (eaat1, eaat2, eaat3) with n-carbamoylglutamate and n-acetylglutamate. | inborn deficiency of the n-acetylglutamate synthase (nags) impairs the urea cycle and causes neurotoxic hyperammonemia. oral administration of n-carbamoylglutamate (ncg), a synthetic analog of n-acetylglutamate (nag), successfully decreases plasma ammonia levels in the affected children. due to structural similarities to glutamate, ncg may be absorbed in the intestine and taken up into the liver by excitatory amino acid transporters (eaats). | 2017 | 29055942 |
| maturation of xenopus laevis oocytes under cadmium and lead exposures: cell biology investigations. | since amphibians are recognised as good models to assess the quality of environments, only few studies have dealt with the impacts of chemical contaminants on their gametes, while toxic effects at this stage will alter all the next steps of their life cycle. therefore, we propose to investigate the oocyte maturation of xenopus laevis in cadmium- and lead-contaminated conditions. the impacts of cadmium and lead ions were explored on events involved in the hormone-dependent process of maturation. ... | 2017 | 29053961 |
| rare gabra3 variants are associated with epileptic seizures, encephalopathy and dysmorphic features. | genetic epilepsies are caused by mutations in a range of different genes, many of them encoding ion channels, receptors or transporters. while the number of detected variants and genes increased dramatically in the recent years, pleiotropic effects have also been recognized, revealing that clinical syndromes with various degrees of severity arise from a single gene, a single mutation, or from different mutations showing similar functional defects. accordingly, several genes coding for gabaa rece ... | 2017 | 29053855 |
| comparative early life stage toxicity of the african clawed frog, xenopus laevis following exposure to selected herbicide formulations applied to eradicate alien plants in south africa. | the rise in pesticides application has increased the need for better understanding of their ecological impacts. the global amphibian declines, for example, have been positively correlated with pesticides use. the differential susceptibility in the developmental stages of amphibians to chemical substances are still largely unknown. we examined the 96-h differential toxicity responses of embryos, premetamorphic and transitional larval stage of xenopus laevis, to six formulated aquatic herbicide pr ... | 2017 | 29051999 |
| a molecular atlas of the developing ectoderm defines neural, neural crest, placode, and nonneural progenitor identity in vertebrates. | during vertebrate neurulation, the embryonic ectoderm is patterned into lineage progenitors for neural plate, neural crest, placodes and epidermis. here, we use xenopus laevis embryos to analyze the spatial and temporal transcriptome of distinct ectodermal domains in the course of neurulation, during the establishment of cell lineages. in order to define the transcriptome of small groups of cells from a single germ layer and to retain spatial information, dorsal and ventral ectoderm was subdivid ... | 2017 | 29049289 |
| geraniin is a diuretic by inhibiting the na+:k+:2cl- cotransporter, nkcc2. | geranium seemannii peyr is a perennial plant endemic in central mexico that has been widely used for its diuretic effect, but the responsible compound of this effect is unknown as well as the mechanism by which the diuretic effect is achieved. geraniin is one of the compounds isolated from this kind of geranium. this study was designed to determinate whether geraniin possesses diuretic activity and to elucidate the mechanism of action. geraniin was extracted and purified from geranium seemannii ... | 2017 | 29046296 |
| aprotinin prevents proteolytic epithelial sodium channel (enac) activation and volume retention in nephrotic syndrome. | volume retention in nephrotic syndrome has been linked to activation of the epithelial sodium channel (enac) by proteolysis of its γ-subunit following urinary excretion of serine proteases such as plasmin. here we tested whether pharmacological inhibition of urinary serine protease activity might protect from enac activation and volume retention in nephrotic syndrome. urine from both nephrotic mice (induced by doxorubicin injection) and nephrotic patients exhibited high aprotinin-sensitive serin ... | 0 | 29042083 |
| pfkfb4 control of akt signaling is essential for premigratory and migratory neural crest formation. | neural crest (nc) specification comprises an early phase, initiating immature nc progenitors formation at neural plate stage, and a later phase at neural fold stage, resulting in a functional premigratory nc that is able to delaminate and migrate. we found that the nc gene regulatory network triggers upregulation of pfkfb4 (6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 4) during this late specification phase. as shown in previous studies, pfkfb4 controls akt signaling in gastrulas and gly ... | 2017 | 29038306 |
| sonic hedgehog antagonists reduce size and alter patterning of the frog inner ear. | sonic hedgehog (shh) signaling plays a major role in vertebrate development, from regulation of proliferation to the patterning of various organs. in amniotes, shh affects dorsoventral patterning in the inner ear but affects anteroposterior patterning in teleost ears. it remains unknown how altered function of shh relates to morphogenetic changes that coincide with the evolution of limbs and novel auditory organs in the ear. in this study, we used the tetrapod, xenopus laevis, to test how increa ... | 2017 | 29030893 |
| negative modulation of the gabaa ρ1 receptor function by l-cysteine. | l-cysteine is an endogenous sulfur-containing amino acid with multiple and varied roles in the central nervous system, including neuroprotection and the maintenance of the redox balance. however, it was also suggested as an excitotoxic agent implicated in the pathogenesis of neurological disorders such as parkinson's and alzheimer's disease. l-cysteine can modulate the activity of ionic channels, including voltage-gated calcium channels and glutamatergic nmda receptors, whereas its effects on ga ... | 0 | 29023772 |
| the first successful observation of in-cell nmr signals of dna and rna in living human cells. | in order to understand intracellular biological events, information on the structure, dynamics and interaction of proteins and nucleic acids in living cells is of crucial importance. in-cell nmr is a promising method to obtain this information. although nmr signals of proteins in human cells have been reported, those of nucleic acids were reported only in xenopus laevis oocytes, i.e., not in human cells. here, dna and rna were introduced into human cells by means of pore formation by bacterial t ... | 2017 | 29022027 |
| fanconi-anemia-associated mutations destabilize rad51 filaments and impair replication fork protection. | fanconi anemia (fa) is a genetic disorder characterized by a defect in dna interstrand crosslink (icl) repair, chromosomal instability, and a predisposition to cancer. recently, two rad51 mutations were reported to cause an fa-like phenotype. despite the tight association of fa/hr proteins with replication fork (rf) stabilization during normal replication, it remains unknown how fa-associated rad51 mutations affect replication beyond icl lesions. here, we report that these mutations fail to prot ... | 2017 | 29020621 |
| an inhibitor of thyroid hormone synthesis protects tail skin grafts transplanted to syngenic adult frogs. | tail regression in amphibian tadpoles during metamorphosis is one of the most dynamic morphological changes in animal development and is induced by thyroid hormone (th). it has been proposed that tail resorption is driven by immunological rejection in xenopus laevis, based on experimental evidence showing that larval skin grafts become atrophic on syngenic recipient adult frogs. this led to the hypothesis that tail regression is induced by an immunological rejection against larval skin-specific ... | 2017 | 28990472 |
| design of light-sensitive nmdars by genetically encoded photo-cross-linkers. | genetic code expansion exploiting unnatural amino acids (uaas) is a powerful technique to create novel protein function in vivo. here, we provide a protocol for the incorporation of two uv-sensitive crosslinking uaas into nmda receptors (nmdars), a type of glutamate-gated ion channels mediating fast synaptic transmission. through heterologous expression in xenopus laevis oocytes, we have identified light-sensitive nmdars of glun2b subtype by using the two-electrode voltage electrophysiology meas ... | 2017 | 28986874 |
| permeant-specific gating of connexin 30 hemichannels. | gap junctions confer interconnectivity of the cytoplasm in neighboring cells via docking of two connexons expressed in each of the adjacent membranes. undocked connexons, referred to as hemichannels, may open and connect the cytoplasm with the extracellular fluid. the hemichannel configuration of connexins (cxs) displays isoform-specific permeability profiles that are not directly determined by the size and charge of the permeant. to further explore ca2+-mediated gating and permeability features ... | 2017 | 28982982 |
| the effect of food properties on grasping and manipulation in the aquatic frog xenopus laevis. | the ability to grasp an object is fundamental from an evolutionary perspective. involved in many daily activities, grasping has been extensively studied in primates and other mammals. yet other groups of tetrapods, including anurans, have also evolved significant forelimb prehensile capacities that are often thought to have originated in an arboreal context. in addition, grasping is also observed in aquatic species. but how aquatic frogs use their forelimbs to capture and manipulate prey remains ... | 2017 | 28982969 |
| desynchronizing embryonic cell division waves reveals the robustness of xenopus laevis development. | the early xenopus laevis embryo is replete with dynamic spatial waves. one such wave, the cell division wave, emerges from the collective cell division timing of first tens and later hundreds of cells throughout the embryo. here, we show that cell division waves do not propagate between neighboring cells and do not rely on cell-to-cell coupling to maintain their division timing. instead, intrinsic variation in division period autonomously and gradually builds these striking patterns of cell divi ... | 2017 | 28978482 |
| the slc2a14 gene, encoding the novel glucose/dehydroascorbate transporter glut14, is associated with inflammatory bowel disease. | background: variations in intestinal antioxidant membrane transporters are implicated in the initiation and progression of inflammatory bowel disease (ibd). facilitated glucose transporter member 14 (glut14), encoded by the solute carrier family 2 member 14 (slc2a14) gene, is a putative transporter for dehydroascorbic acid and glucose. although information on the gene is limited, shorter and longer glut14 isoforms have been identified. we hypothesized that glut14 mediates glucose and dehydroasco ... | 2017 | 28971850 |
| differential cytolocation and functional assays of the two major human slc30a8 (znt8) isoforms. | the non-synonymous single nucleotide polymorphism (snp) rs13266634 in human zinc transporter 8, znt8 (slc30a8), leads to a r325 variant, which is associated with an increased risk of developing type 2 diabetes (t2d). although the molecular details remain unknown, the mutation is thought to alter the kinetics of zinc transport into insulin granules in pancreatic β-cells. nevertheless, analysis of znt8 sequences from several animals shows that the amino acid at position 325 is poorly conserved. ap ... | 2017 | 28965566 |