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disruptive effects of two organotin pesticides on the thyroid signaling pathway in xenopus laevis during metamorphosis.organotin compounds are the ubiquitous environmental pollutants due to their wide industrial and agricultural applications and unexpected releasing into the environment, which show characteristic of endocrine disruptors to interfere with the synthesis, receptor binding or action of endogenous-hormones. organotin pesticides (otps) are used in agriculture and may impact endocrine functions on organisms. thyroid hormones (ths) play fundamental roles in regulating the basal metabolism and energy bal ...201931476497
disruption of the lotus japonicus transporter ljnpf2.9 increases shoot biomass and nitrate content without affecting symbiotic performances.after uptake from soil into the root tissue, distribution and allocation of nitrate throughout the whole plant body, is a critical step of nitrogen use efficiency (nue) and for modulation of plant growth in response to various environmental conditions. in legume plants nitrate distribution is also important for the regulation of the nodulation process that allows to fix atmospheric n (n2) through the symbiotic interaction with rhizobia (symbiotic nitrogen fixation, snf).201931470797
comparative analysis of the developmental toxicity in xenopus laevis and danio rerio induced by al2 o3 nanoparticle exposure.engineered aluminum oxide nanoparticles (al2 o3 nps) having high-grade thermal stability and water-dispersion properties are extensively used in different industries and personal care products. toxicological response evaluation of these nps is indispensable in assessing the health risks and exposure limits because of their industrial disposal into the aquatic environment. we assessed and compared the developmental toxicity of al2 o3 nps in xenopus laevis and danio rerio over a period of 96 h usi ...201931470468
divergent roles of the wnt/pcp formin daam1 in renal ciliogenesis.kidneys are composed of numerous ciliated epithelial tubules called nephrons. each nephron functions to reabsorb nutrients and concentrate waste products into urine. defects in primary cilia are associated with abnormal formation of nephrons and cyst formation in a wide range of kidney disorders. previous work in xenopus laevis and zebrafish embryos established that loss of components that make up the wnt/pcp pathway, daam1 and arhgef19 (wgef) perturb kidney tubulogenesis. dishevelled, which act ...201931469868
in cell nmr spectroscopy: investigation of g-quadruplex structures inside living xenopus laevis oocytes.g-quadruplexes are inherently polymorphic nucleic acid structures. their folding topology depends on the nucleic acid primary sequence and on physical-chemical environmental factors. hence, it remains unclear if a g-quadruplex topology determined in the test tube (in vitro) will also form in vivo. characterization of g-quadruplexes in their native environment has been proposed as an efficient strategy to tackle this issue. so far, characterization of g-quadruplex structures in living cells has r ...201931444765
characterization and proteomic-transcriptomic investigation of monocarboxylate transporter 6 knockout mice: evidence of a potential role in glucose and lipid metabolism.monocarboxylate transporter 6 [(mct6), slc16a5] is an orphan transporter with no known endogenous substrates or physiological role. previous in vitro and in vivo experiments investigated mct6 substrate/inhibitor specificity in xenopus laevis oocytes; however, these data remain limited. transcriptomic changes in the livers of mice undergoing different dieting schemes have suggested that mct6 plays a role in glucose and lipid metabolism. the objectives of this study were 1) to develop a novel knoc ...201931436537
bisphenol a, bisphenol af, di-n-butyl phthalate, and 17β-estradiol have shared and unique dose-dependent effects on early embryo cleavage divisions and development in xenopus laevis.bisphenol a (bpa), bisphenol af (bpaf), and di-n-butyl phthalate (dbp) are widespread compounds used in the production of plastics. we used xenopus laevis to compare their effects on early embryo cell division and development. directly after in vitro fertilizations, embryos were exposed to bpa, bpaf, dbp, or 17β-estradiol (e2) for up to 96 h. bpa (1-50 μm) and bpaf (0.003-25 μm) caused disrupted cleavage divisions, slowed cytokinesis, and cellular dissociation within 1-6 h. flexures of the spina ...201930579998
molecular charge associated with antiarrhythmic actions in a series of amino-2-cyclohexyl ester derivatives.a series of amino-2-cyclohexyl ester derivatives were studied for their ion channel blocking and antiarrhythmic actions in the rat and a structure-activity analysis was conducted. the compounds are similar in chemical structure except for ionizable amine groups (pk values 6.1-8.9) and the positional arrangements of aromatic naphthyl moieties. ventricular arrhythmias were produced in rats by coronary-artery occlusion or electrical stimulation. the electrophysiological effects of these compounds o ...201930571955
lack of evidence for synaptic high-affinity γ-hydroxybutyric acid (ghb) transport in rat brain synaptosomes and 11 na+ -dependent slc neurotransmitter transporters.γ-hydroxybutyric acid (ghb) is an endogenous compound proposed to act as a neurotransmitter. na+ -dependent, high-affinity ghb transport has long been considered important evidence supporting this hypothesis. however, the molecular identity of such a high-affinity transporter remains unknown. in this study, we sought to identify and characterize ghb synaptic transport through a series of studies using both native and recombinant systems with the ultimate aim of providing evidence to clarify the ...201930570143
lysine demethylase 3a in craniofacial and neural development during xenopus embryogenesis.epigenetic modifier lysine demethylase 3a (kdm3a) specifically demethylates mono‑ and di‑methylated ninth lysine of histone 3 and belongs to the jumonji domain‑containing group of demethylases. kdm3a serves roles during various biological and pathophysiological processes, including spermatogenesis and metabolism, determination of sex, androgen receptor‑mediated transcription and embryonic carcinoma cell differentiation. in the present study, physiological functions of kdm3a were evaluated during ...201930569092
ospht1;3 mediates uptake, translocation, and remobilization of phosphate under extremely low phosphate regimes.plant roots rely on inorganic orthophosphate (pi) transporters to acquire soluble pi from soil solutions that exists at micromolar levels in natural ecosystems. here, we functionally characterized a rice (oryza sativa) pi transporter, os phosphate transporter-1;3 (ospht1;3), that mediates pi uptake, translocation, and remobilization. ospht1;3 was directly regulated by os phosphate starvation response-2 and, in response to pi starvation, showed enhanced expression in young leaf blades and shoot b ...201930567970
increasing nitroxide lifetime in cells to enable in-cell protein structure and dynamics measurements by electron spin resonance spectroscopy.there is increasing evidence that the stability, structure, dynamics, and function of many proteins differ in cells versus in vitro. the determination of protein structure and dynamics within the native cellular environment may lead to better understanding of protein behavior. electron spin resonance (esr) has emerged as a technique that can report on protein structure and dynamics within cells. nitroxide based spin labels are capable of reporting on protein dynamics, structure, and backbone fle ...201930550988
dual cationic-anionic profiling of metabolites in a single identified cell in a live xenopus laevis embryo by microprobe ce-esi-ms.in situ capillary microsampling with capillary electrophoresis (ce) electrospray ionization (esi) mass spectrometry (ms) enabled the characterization of cationic metabolites in single cells in complex tissues and organisms. for deeper coverage of the metabolome and metabolic networks, analytical approaches are needed that provide complementary detection for anionic metabolites, ideally using the same instrumentation. described here is one such approach that enables sequential cationic and anioni ...201930542678
radiobiological characteristics of descendant progeny of fish and amphibian cells that survive the initial ionizing radiation dose.to evaluate the development of delayed lethal mutations, the production of medium borne lethal bystander signals, and the acquirement of radiosensitive or radioresistant traits in distant descendant progeny of fish and amphibian cells surviving ionizing radiation materials and methods: american eel brain endothelial cells (eelb) and african clawed frog epithelial cells (a6) were initially irradiated with gamma rays at 0.5 gy or 2 gy. ionizing radiation (ir)-surviving cells were grown for 27 popu ...201930530089
a xenopus tadpole alternative model to study innate-like t cell-mediated anti-mycobacterial immunity.owing to the high incidence of multi-drug resistance and challenges posed by the complex and long duration of treatments, mycobacterium tuberculosis (mtb) infections remain a significant clinical burden, which would benefit from development of novel immuno-therapeutic-based treatment strategies. among early immune effectors, invariant or innate-like (i)t cells are attracting attention because of their potential regulatory activity, which can shape anti-mycobacterial immune responses. unlike conv ...201930521838
enhanced visual experience rehabilitates the injured brain in xenopus tadpoles in an nmdar-dependent manner.traumatic brain injuries introduce functional and structural circuit deficits that must be repaired for an organism to regain function. we developed an injury model in which xenopus laevis tadpoles are given a penetrating stab wound that damages the optic tectal circuit and impairs visuomotor behavior. in tadpoles, as in other systems, injury induces neurogenesis. the newly generated neurons are thought to integrate into the existing circuit; however, whether they integrate via the same mechanis ...201930517041
sr 57227a is a partial agonist/partial antagonist of 5-ht3 receptor and inhibits subsequent 5-ht- or sr 57227a-induced 5-ht3 receptor current.the serotonin (5-hydroxytryptamine) type 3 (5-ht3) receptors are transmembrane ligand-gated ion channels. although several 5-ht3 receptor agonists have been used as preclinical tools, sr 57227a is the most commonly used 5-ht3 receptor agonist with the ability to cross the blood brain barrier. however, the precise pharmacological profile of sr 57227a remains unclear. therefore, we examined the pharmacological profile of sr 57227a at the 5-ht3a and 5-ht3ab receptors. we microinjected xenopus laevi ...201930509492
expression pattern and histone acetylation of energy metabolic genes in xenopus laevis liver in response to diet statuses.amphibians can survive without food for relatively longer periods by reducing the locomotor activity and metabolic rate and can recover quickly with refeeding from a dormant state. to clarify the molecular mechanism underlying this survival strategy, we investigated serum biochemical parameters, the transcript levels of energy metabolic genes, and global and gene-specific histone modifications in the liver of adult male xenopus laevis, which were fed, fasted, or refed after fasting. glucose, tri ...201930460762
how thyroid hormones and their inhibitors affect cartilage growth and shape in the frog xenopus laevis.understanding how skeleton changes shape in ontogeny is fundamental to understanding how its shape diversifies in phylogeny. amphibians pose a special case because their jaw and throat skeleton consists of cartilages that are dramatically reshaped midway through life to support new feeding and breathing styles. although amphibian metamorphosis is commonly studied by immersing larvae in thyroid hormones (th), how individual cartilages respond to th is poorly understood. this study documents the e ...201930456781
class a scavenger receptors mediate extracellular dsrna sensing, leading to downstream antiviral gene expression in a novel american toad cell line, bufotad.viral double-stranded (ds)rna is a potent pathogen-associated molecular pattern (pamp), capable of inducing a strong antiviral state within the cell, protecting the cell from virus infection. in mammals and fish, sensing extracellular dsrna is mediated by cell-surface class a scavenger receptors (sr-as). currently, very little is known about sr-as in amphibians, including: sequence, expression patterns and function. to this end, sr-a expression and function was studied in a novel american toad ( ...201930452932
proteolytic activation of bmps: analysis of cleavage in xenopus oocytes and embryos.bone morphogenetic proteins (bmps) are synthesized as inactive precursors that are cleaved to generate active ligands, along with prodomain fragments that can modulate growth factor activity. here we provide three protocols that can be used to examine the process of proteolytic activation of bmps. the first protocol describes how to generate radiolabeled bmp precursor proteins in xenopus oocytes and then analyze the time course of precursor cleavage by recombinant enzymes in vitro. the second pr ...201930414129
microtransplantation of human brain receptors into oocytes to tackle key questions in drug discovery.it is important in drug discovery to demonstrate that activity of novel drugs found by screening on recombinant receptors translates to activity on native human receptors in brain areas affected by disease. in this review, we summarise the development and use of the microtransplantation technique. native receptors are reconstituted from human brain tissues into oocytes from the frog xenopus laevis where they can be functionally assessed. oocytes microtransplanted with hippocampal tissue from an ...201930395928
a modified tripeptide motif of rs1 (rsc1a1) down-regulates exocytotic pathways of human na+-d-glucose cotransporters sglt1, sglt2, and glucose sensor sglt3 in the presence of glucose.a domain of protein rs1 (rsc1a1) called rs1-reg down-regulates the plasma membrane abundance of na+-d-glucose cotransporter sglt1 by blocking the exocytotic pathway at the trans-golgi. this effect is blunted by intracellular glucose but prevails when serine in a qsp (gln-ser-pro) motif is replaced by glutamate [rs1-reg(s20e)]. rs1-reg binds to ornithine decarboxylase (odc) and inhibits odc in a glucose-dependent manner. because the odc inhibitor difluoromethylornithine (dfmo) acts like rs1-reg(s ...201930355744
functional studies of transcriptional cofactors via microinjection-mediated gene editing in xenopus.the anuran xenopus laevis has been studied for decades as a model for vertebrate cell and developmental biology. more recently, the highly related species xenopus tropicalis has offered the opportunity to carry out genetic studies due to its diploid genome as compared to the pseudo-tetraploid xenopus laevis. amphibians undergo a biphasic development: embryogenesis to produce a free-living tadpoles and subsequent metamorphosis to transform the tadpole to a frog. this second phase mimics the so-ca ...201930353533
comprehensive analysis of formin localization in xenopus epithelial cells.reorganization of the actin cytoskeleton is crucial for cellular processes, including cytokinesis and cell-cell junction remodeling. formins are conserved processive actin-polymerizing machines that regulate actin dynamics by nucleating, elongating, and bundling linear actin filaments. because the formin family is large, with at least 15 members in vertebrates, there have not been any comprehensive studies examining formin localization and function within a common cell type. here, we characteriz ...201930379611
anticipation of food intake induces phosphorylation switch to regulate basolateral amino acid transporter lat4 (slc43a2) function.amino acid absorption requires luminal uptake into and subsequent basolateral efflux out of epithelial cells, with the latter step being critical to regulate the intracellular concentration of the amino acids. the basolateral essential neutral amino acid uniporter lat4 (slc43a2) has been suggested to drive the net efflux of non-essential and cationic amino acids via parallel amino acid antiporters by recycling some of their substrates; its deletion has been shown to cause defective postnatal gro ...201930379325
high-affinity k+ transporters from a halophyte, sporobolus virginicus, mediate both k+ and na+ transport in transgenic arabidopsis, x. laevis oocytes and yeast.class ii high-affinity potassium transporters (hkts) have been proposed to mediate na+-k+ co-transport in plants, as well as na+ and k+ homeostasis under k+-starved and saline environments. we identified class ii hkts, namely svhkt2;1 and svhkt2;2 (svhkts), from the halophytic turf grass, sporobolus virginicus. svhkt2;2 expression in s. virginicus was up-regulated by nacl treatment, while svhkt2;1 expression was assumed to be up-regulated by k+ starvation and down-regulated by nacl treatment. lo ...201930325438
generation and analysis of xenopus laevis models of retinal degeneration using crispr/cas9.xenopus laevis have proven to be a useful system for rapid generation and analysis of transgenic models of human retinal disease. however, experimental approaches in this system were limited by lack of a robust knockdown or knockout technology. here we describe a protocol for generation of cas9-edited x. laevis embryos. the technique introduces point mutations into the genome of x. laevis resulting in in-frame and out-of-frame insertions and deletions that allow modeling of both dominant and rec ...201930324446
expression of the hormonal fgf co-receptor klotho beta in the xenopus laevis model.klotho beta (klb), a single-pass transmembrane protein, has been described as a co-receptor for endocrine fgfs, such as fgf15/19 and fgf21, to regulate critical metabolic processes in multiple organs and tissues in adult mice. however, its function during early embryonic development remains largely unknown. in this paper, we evaluated for the first time the expression of klb mrna during early development of xenopus laevis by rt-pcr and whole mount in situ hybridization. rt-pcr experiments showed ...201930259590
expression cloning human and rat renal cortex na/pi cotransporters: behind the scenes in the murer laboratory.in the pre-genomic era, the cloning of a cdna represented a significant achievement, particularly if the gene of interest encoded a membrane protein. at the time, molecular probes such as partial peptide sequences, suitable nucleic acid sequences, or antibodies were unavailable for most proteins and the "sodium-phosphate transporter" was no exception. in contrast, brush-border membrane vesicles and epithelial cell culture experiments had established a reliable set of functional hallmarks that de ...201930175377
comparisons of socs mrna and protein levels in xenopus provide insights into optic nerve regenerative success.in vertebrates from fishes to mammals, optic nerve injury induces increased expression ofsuppressor of cytokine signaling 3(socs3) mrna, a modulator of cytokine signaling that is known to inhibit cns axon regeneration. unlike amniotes, however, anamniotes successfully regenerate optic axons, despite this increase. to address this seeming paradox, we examined the socs3 response to optic nerve injury in the frog,xenopus laevis, at both the mrna and protein levels. far from being only transiently i ...201930315759
design, synthesis, and pharmacological evaluation of novel β2/3 subunit-selective γ-aminobutyric acid type a (gabaa) receptor modulators.subunit-selective modulation of γ-aminobutyric acid type a receptors (gabaar) is considered to exert fewer side effects compared to unselective clinically used drugs. here, the β2/3 subunit-selective gabaar modulators valerenic acid (va) and loreclezole (lor) guided the synthesis of novel subunit-selective ligands with simplified structures. we studied their effects on gabaars expressed in xenopus laevis oocytes using two-microelectrode voltage clamp technique. five compounds showed significantl ...201930289721
lymphocyte deficiency induced by sublethal irradiation in xenopus.in many studies of diseases affecting amphibians, it is important to determine to what extent lymphocyte-mediated defenses are involved. for example, in studies of the nature of the immune response of xenopus laevis to the amphibian chytrid fungus, batrachochytrium dendrobatidis, it was essential to determine if mucosal antimicrobial peptides or lymphocyte-mediated immunity was most important for resistance to this skin pathogen. in this protocol, we describe a method for sublethal irradiation t ...201930104411
mass spectrometry-based absolute quantification of single xenopus embryo proteomes.early xenopus development is characterized by a poor correlation between global mrna and protein abundances due to maternal mrna and protein loading. therefore, proteome profiling is necessary to study gene expression dynamics during early xenopus development. in contrast to mammals, single xenopus eggs and embryos contain enough protein to allow identification and quantification of thousands of proteins using mass spectrometry-based proteomics. in addition to investigating developmental process ...201930104410
regulation of melanopsin signaling: key interactions of the nonvisual photopigment.melanopsin is a g protein-coupled receptor with a peak sensitivity in the blue part of the spectrum, which plays a key role in nonvisual light-mediated signaling. recently, its importance in forming visual pathway as well as its role in blood vessels photorelaxation was also revealed. melanopsin was discovered in 1998 in xenopus leavis. since then, the melanopsin presence was demonstrated across the species. the existence of two melanopsin genes (opn4m and opn4x) as well as melanopsin isoforms r ...201930102761
copper uptake mechanism of arabidopsis thaliana high-affinity copt transporters.copper (cu) is an essential plant micronutrient. under scarcity, cu2+ is reduced to cu+ and taken up through specific high-affinity transporters (copts). in arabidopsis, the copt family consists of six members, either located at the plasma membrane (copt1, copt2, and copt6) or in internal membranes (copt3 and copt5). cu uptake by copt proteins has been mainly assessed through complementation studies in corresponding yeast mutants, but the mechanism of this transport has not been elucidated. to t ...201930043153
following endocrine-disrupting effects on gene expression in xenopus laevis.endocrine-disrupting chemicals (edcs), found in all categories of chemicals, are suspected to be a cause of declining well-being and human health, both as single molecules and as mixtures. it is therefore necessary to develop high throughput methods to assess the endocrine-disrupting potential of multiple chemicals currently on the market that are as yet untested. an advantage of in vivo chemical screening is that it provides a full spectrum of physiological impacts exerted by a given chemical. ...201930042138
assessing antibody responses to pathogens or model antigens in xenopus by enzyme-linked immunosorbent assay (elisa).xenopus laevis-specific monoclonal antibodies recognize igm and igy antibodies not only from x. laevis but also x. tropicalis as well as a variety of amphibian species including ranidae, bufonidae, and even some salamanders. these reagents are very useful to assess antibody responses from the serum or other animal secretions (e.g., peritoneal fluid). we present here an enzyme-linked immunosorbent assay (elisa) optimized for amphibians that permits users to detect and titrate the presence of each ...201930042135
studies of limb regeneration in larval xenopus.a basic protocol is given for animal maintenance and surgery in studies of hindlimb regeneration in larval xenopus laevis unlike urodele limbs, those of larval frogs typically show much more variation in the extent of regeneration after amputation. such variation can be reduced by optimizing the conditions of larval maintenance to regulate the rates of growth and development, by selecting only larvae with normal rates of growth and morphological development for experimental use, and by attention ...201929895566
investigating the cellular and molecular mechanisms of wound healing in xenopus oocytes and embryos.the african clawed frog xenopus has remarkable capacities to heal wounds rapidly and to regenerate complex tissues. because of its experimental tractability, studies using xenopus oocytes, embryos, and larvae have contributed extensively to our understanding of the molecular and cellular mechanisms underpinning wound healing and tissue regeneration. in this protocol, we describe wound-healing assays following mechanical or laser injuries of oocytes and multicellular epithelia in xenopus laevis e ...201929895564
ex vivo eye tissue culture methods for xenopus.lens regeneration can be studied in whole animals following removal of the original lens (lentectomy). however, culturing a whole animal can be impractical for assays involving small molecule inhibitors or proteins. ex vivo eye tissue culture is an alternative approach for examining lens regeneration. the ex vivo culture system offers certain advantages when compared to the in vivo regeneration assay, as the percentage of cases showing lens differentiation can exceed that seen in whole animals. ...201929895561
bile acids inhibit human purinergic receptor p2x4 in a heterologous expression system.we recently demonstrated that bile acids, especially tauro-deoxycholic acid (t-dca), modify the function of the acid-sensing ion channel asic1a and other members of the epithelial sodium channel (enac)/degenerin (deg) ion channel family. surprisingly, asic1 shares a high degree of structural similarity with the purinergic receptor p2x4, a nonselective cation channel transiently activated by atp. p2x4 is abundantly expressed in the apical membrane of bile duct epithelial cells and is therefore ex ...201930988062
pacap-38 and pacap(6-38) degranulate rat meningeal mast cells via the orphan mrgb3-receptor.infusion of pituitary adenylate cyclase activating peptide-38 (pacap-38) provokes migraine attacks in migraineurs and headache in non-migraineurs. adverse events like long-lasting flushing and heat sensation can be terminated with oral antihistamine treatment, indicating the involvement of mast cell activation after pacap-infusion. degranulation of rat peritoneal mast cells was provoked by several isoforms of pacap via previously unknown receptor pharmacology. the effect might thus be mediated e ...201930983973
molecular markers for corneal epithelial cells in larval vs. adult xenopus frogs.corneal epithelial stem cells (cescs) and their proliferative progeny, the transit amplifying cells (tacs), are responsible for maintaining the integrity and transparency of the cornea. these stem cells (scs) are widely used in corneal transplants and ocular surface reconstruction. molecular markers are essential to identify, isolate and enrich for these cells, yet no definitive cesc marker has been established. an extensive literature survey shows variability in the expression of putative cesc ...201930981716
molecular and functional characterization of a short-type peptidoglycan recognition protein, pgrp-s in the amphibian xenopus laevis.peptidoglycan recognition proteins (pgrps) are a family of pattern recognition receptors (prrs) involved in host antibacterial responses, and their functions have been characterized in most invertebrate and vertebrate animals. however, little information is available regarding the function of frog pgrps. in this study, a short-type pgrp (termed xl-pgrp-s) gene was identified in the african clawed frog, xenopus laevis. the predicted protein of xl-pgrp-s contains several structural features known ...201930980872
loss of function of kmt2d, a gene mutated in kabuki syndrome, affects heart development in xenopus laevis.kabuki syndrome is a haploinsufficient congenital multi-organ malformation syndrome, which frequently includes severe heart defects. mutations in the histone h3k4 methyltransferase kmt2d have been identified as the main cause of kabuki syndrome, however, the role of kmt2d in heart development remains to be characterized.201930980591
antimicrobial peptides of multicellular organisms: my perspective.antimicrobial peptides of multicellular organisms were first characterized in the 1980s by investigators who felt that known systems of immunity could not explain what they observed: the resistance to bacterial infection of a cecropia moth pupa lacking antibodies or lymphocytes (cecropins (steiner 1981)), the potent microbicidal activity of neutrophils from a rabbit (defensins (selsted et al. 1985)), and the healing of a wound on the skin of the african clawed frog without infection in a non-ste ...201930980349
mitotic replisome disassembly depends on traip ubiquitin ligase activity.we have shown previously that the process of replication machinery (replisome) disassembly at the termination of dna replication forks in the s-phase is driven through polyubiquitylation of one of the replicative helicase subunits (mcm7) by cul2lrr1 ubiquitin ligase. interestingly, upon inhibition of this pathway in caenorhabditis elegans embryos, the replisomes retained on chromatin were unloaded in the subsequent mitosis. here, we show that this mitotic replisome disassembly pathway exists in ...201930979826
evaluation of cyclic luciferin as a substrate for luminescence measurements in in vitro and in vivo applications.bioluminescence imaging (bli) is a powerful tool for cell tracking, monitoring of gene delivery and expression in small laboratory animals. an alternative luciferase (luc) substrate cyclic luciferin (cycluc) was recently advanced for bli applications as providing a stronger, more stable signal at significantly lower doses than the classical substrate d-luciferin (d-luc) increasing sensitivity of luc detection 10 to 100 times. we evaluated benefits of using cycluc in in vivo studies in mice injec ...201930979501
in vivo and in vitro quantitative analysis of neural crest cell migration.the neural crest is an embryonic cell population induced at the border of the neural plate from where it delaminates and migrates long distances across the embryo. due to its extraordinary migratory capabilities, the neural crest has become a powerful system to study cellular and molecular aspects of collective and single cell migration both in vivo and in vitro. here we provide detailed protocols used to perform quantitative analysis of molecular and cellular aspects of xenopus laevis neural cr ...201930977071
hybrid-type and two-tetrad antiparallel telomere dna g-quadruplex structures in living human cells.although the telomeric sequence has been reported to form various g-quadruplex topologies in vitro and in xenopus laevis oocytes, in living human cells, the topology of telomeric dna g-quadruplex remains a challenge. to investigate the human telomeric dna g-quadruplex in a more realistic human cell environment, in the present study, we demonstrated that the telomeric dna sequence can form two hybrid-type and two-tetrad antiparallel g-quadruplex structures by in-cell 19f nmr in living human cells ...201930976813
autophagy in xenopus laevis rod photoreceptors is independently regulated by phototransduction and misfolded rhop23h.we previously reported autophagic structures in rod photoreceptors expressing a misfolding rho (rhodopsin) mutant (rhop23h), suggesting that autophagy may play a role in degrading the mutant rho and/or be involved in photoreceptor cell death. to further examine autophagy in normal and diseased rods, we generated transgenic xenopus laevis tadpoles expressing the dually fluorescent autophagy marker mrfp-egfp-lc3 in rods, which changes from green to yellow and finally red as autophagic structures d ...201930975014
optoelectronic control of single cells using organic photocapacitors.optical control of the electrophysiology of single cells can be a powerful tool for biomedical research and technology. here, we report organic electrolytic photocapacitors (oepcs), devices that function as extracellular capacitive electrodes for stimulating cells. oepcs consist of transparent conductor layers covered with a donor-acceptor bilayer of organic photoconductors. this device produces an open-circuit voltage in a physiological solution of 330 mv upon illumination using light in a tiss ...201930972364
thermal reduction of graphene oxide mitigates its in vivo genotoxicity toward xenopus laevis tadpoles.the worldwide increase of graphene family materials raises the question of the potential consequences resulting from their release in the environment and future consequences on ecosystem health, especially in the aquatic environment in which they are likely to accumulate. thus, there is a need to evaluate the biological and ecological risk but also to find innovative solutions leading to the production of safer materials. this work focuses on the evaluation of functional group-safety relationshi ...201930970633
n-glycosylation-dependent regulation of hk2p17.1 currents.two pore-domain potassium (k2p) channels mediate potassium background currents that stabilize the resting membrane potential and facilitate action potential repolarization. in the human heart, hk2p17.1 channels are predominantly expressed in the atria and purkinje cells. reduced atrial hk2p17.1 protein levels were described in patients with atrial fibrillation or heart failure. genetic alterations in hk2p17.1 were associated with cardiac conduction disorders. little is known about posttranslatio ...201930969900
modeling congenital kidney diseases in xenopus laevis.congenital anomalies of the kidney and urinary tract (cakut) occur in ∼1/500 live births and are a leading cause of pediatric kidney failure. with an average wait time of 3-5 years for a kidney transplant, the need is high for the development of new strategies aimed at reducing the incidence of cakut and preserving renal function. next-generation sequencing has uncovered a significant number of putative causal genes, but a simple and efficient model system to examine the function of cakut genes ...201930967415
critical role of an mhc class i-like/innate-like t cell immune surveillance system in host defense against ranavirus (frog virus 3) infection.besides the central role of classical major histocompatibility complex (mhc) class ia-restricted conventional cluster of differentiation 8 (cd8) t cells in antiviral host immune response, the amphibian xenopuslaevis critically rely on mhc class i-like (mhc1b10.1.l or xnc10)-restricted innate-like (i)t cells (ivα6 t cells) to control infection by the ranavirus frog virus 3 (fv3). to complement and extend our previous reverse genetic studies showing that ivα6 t cells are required for tadpole survi ...201930959883
is normalized hindlimb length measurement in assessment of thyroid disruption in the amphibian metamorphosis assay relevant?the amphibian metamorphosis assay represents an oecd level 3 and edsp tier 1 ecotoxicity test assessing thyroid activity of chemicals in african clawed frog (xenopus laevis). to evaluate the effectiveness of snout-vent length (svl) normalization of hindlimb length (hll), correlation between the hll and svl or body weight was evaluated in the control groups of 10 individual studies from three laboratories. two studies required separate analysis of the nieuwkoop-faber (nf) stage ≤60 and >60 animal ...201930957914
nacl-induced csrci2e and csrci2f interact with aquaporin cspip2;1 to reduce water transport in camelina sativa l.rare cold-inducible 2 (rci2) proteins are small hydrophobic proteins that are known to be localized in cellular membranes. the function of rci2 proteins has been reported to be associated with low-temperature, salt, and drought stress tolerances as a membrane potential regulator; however, the specific functions are still unknown. the pip2 (plasma membrane intrinsic protein 2) aquaporins are proteins that transport water and small solutes into the cell. the expression and activity of pip2 protein ...201930954220
functional and structural analysis of rare slc2a2 variants associated with fanconi-bickel syndrome and metabolic traits.deleterious variants in slc2a2 cause fanconi-bickel syndrome (fbs), a glycogen storage disorder, whereas less common variants in slc2a2 associate with numerous metabolic diseases. phenotypic heterogeneity in fbs has been observed, but its causes remain unknown. our goal was to functionally characterize rare slc2a2 variants found in fbs and metabolic disease-associated variants to understand the impact of these variants on glut2 activity and expression and establish genotype-phenotype correlation ...201930950137
gpcr-independent activation of g proteins promotes apical cell constriction in vivo.heterotrimeric g proteins are signaling switches that control organismal morphogenesis across metazoans. in invertebrates, specific gpcrs instruct g proteins to promote collective apical cell constriction in the context of epithelial tissue morphogenesis. in contrast, tissue-specific factors that instruct g proteins during analogous processes in vertebrates are largely unknown. here, we show that daple, a non-gpcr protein linked to human neurodevelopmental disorders, is expressed specifically in ...201930948426
pyrophosphate stimulates the phosphate-sodium symporter of trypanosoma brucei acidocalcisomes and saccharomyces cerevisiae vacuoles.inorganic pyrophosphate (ppi) is a by-product of biosynthetic reactions and has bioenergetic and regulatory roles in a variety of cells. here we show that ppi and other pyrophosphate-containing compounds, including polyphosphate (polyp), can stimulate sodium-dependent depolarization of the membrane potential and pi conductance in xenopus oocytes expressing a saccharomyces cerevisiae or trypanosoma brucei na+/pi symporter. ppi is not taken up by xenopus oocytes, and deletion of the tbpho91 spx do ...201930944211
new roles for wnt and bmp signaling in neural anteroposterior patterning.during amphibian development, neural patterning occurs via a two-step process. spemann's organizer secretes bmp antagonists that induce anterior neural tissue. a subsequent caudalizing step re-specifies anterior fated cells to posterior fates such as hindbrain and spinal cord. the neural patterning paradigm suggests that a canonical wnt-signaling gradient acts along the anteroposterior axis to pattern the nervous system. wnt activity is highest in the posterior, inducing spinal cord, at intermed ...201930936121
desmoplakin is required for epidermal integrity and morphogenesis in the xenopus laevis embryo.desmoplakin (dsp) is a unique and critical desmosomal protein, that is integral to epidermal development. however, it is unclear whether this protein is required specifically for epidermal morphogenesis. using morpholinos or crispr/cas9 mutagenesis we decreased the function of dsp in frog embryos to better understand its role during epidermal development. dsp morphant and mutant embryos had developmental defects such as epidermal fragility that mimicked what has been reported in mammals. most im ...201930935896
identification and functional characterization of the chloride channel gene, gsclc-c2 from wild soybean.the anionic toxicity of plants under salt stress is mainly caused by chloride (cl-). thus cl- influx, transport and their regulatory mechanisms should be one of the most important aspects of plant salt tolerance studies, but are often sidelined by the focus on sodium (na+) toxicity and its associated adaptations. plant chloride channels (clcs) are transport proteins for anions including cl- and nitrate (no3-), and are critical for nutrition uptake and transport, adjustment of cellular turgor, st ...201930935372
induction of a spindle-assembly-competent m phase in xenopus egg extracts.normal mitotic spindle assembly is a prerequisite for faithful chromosome segregation and unperturbed cell-cycle progression. precise functioning of the spindle machinery relies on conserved architectural features, such as focused poles, chromosome alignment at the metaphase plate, and proper spindle length. these morphological requirements can be achieved only within a compositionally distinct cytoplasm that results from cell-cycle-dependent regulation of specific protein levels and specific po ...201930930041
trace, machine learning of signal images for trace-sensitive mass spectrometry: a case study from single-cell metabolomics.recent developments in high-resolution mass spectrometry (hrms) technology enabled ultrasensitive detection of proteins, peptides, and metabolites in limited amounts of samples, even single cells. however, extraction of trace-abundance signals from complex data sets ( m/ z value, separation time, signal abundance) that result from ultrasensitive studies requires improved data processing algorithms. to bridge this gap, we here developed "trace", a software framework that incorporates machine lear ...201930929422
recovery of the xenopus laevis heart from ros-induced stress utilizes conserved pathways of cardiac regeneration.urodele amphibians and some fish are capable of regenerating up to a quarter of their heart tissue after cardiac injury. while many anuran amphibians like xenopus laevis are not capable of such feats, they are able to repair lesser levels of cardiac damage, such as that caused by oxidative stress, to a far greater degree than mammals. using an optogenetic stress induction model that utilizes the protein killerred, we have investigated the extent to which mechanisms of cardiac regeneration are co ...201930924142
ursodeoxycholic acid inhibits uptake and vasoconstrictor effects of taurocholate in human placenta.intrahepatic cholestasis of pregnancy (icp) causes increased transfer of maternal bile acids to the fetus and an increased incidence of sudden fetal death. treatment includes ursodeoxycholic acid (udca), but it is not clear if udca protects the fetus. this study explores the placental transport of the bile acid taurocholate (tc) by the organic anion-transporting polypeptide, (oatp)4a1, its effects on the placental proteome and vascular function, and how these are modified by udca. various method ...201930922127
latrophilin2 is involved in neural crest cell migration and placode patterning in xenopus laevis.latrophilin2 (lphn2) is an adhesion-class of g protein-coupled receptor with an unknown function in development. here, we show that xenopus laevis lphn2 (xlphn2) is involved in the migration and differentiation of neural crest (nc) cells and placode patterning in xenopus laevis embryos. although xlphn2 mrna was detected throughout embryogenesis, it was expressed more abundantly in the placode region. morpholino antisense oligonucleotide-mediated knockdown of xlphn2 caused abnormal migration of n ...201930919913
regulation of na+-k+-cl- cotransporter type 2 by the with no lysine kinase-dependent signaling pathway.na+-k+-cl- cotransporter type 2 (nkcc2) is confined to the apical membrane of the thick ascending limb of henle, where it reabsorbs a substantial fraction of the ultrafiltered nacl load. it is expressed along this nephron segment as three main splice variants (called nkcc2a, nkcc2b, and nkcc2f) that differ in residue composition along their second transmembrane domain and first intracellular cytosolic connecting segment (cs2). nkcc2 is known to be activated by cell shrinkage and intracellular [c ...201930917032
agr2-interacting prod1-like protein tfp4 from xenopus laevis is necessary for early forebrain and eye development as well as for the tadpole appendage regeneration.the agr family genes, ag1, agr2, and agr3, encode for the thioredoxin domain containing secreted proteins and are specific only for vertebrates. these proteins are attracting increasing attention due to their involvement in many physiological and pathological processes, including exocrine secretion, cancer, regeneration of the body appendages, and the early brain development. at the same time, the mode by which agrs regulate intracellular processes are poorly understood. despite that the recepto ...201930912273
xmap215 promotes microtubule-f-actin interactions to regulate growth cone microtubules during axon guidance in xenopuslaevis.it has long been established that neuronal growth cone navigation depends on changes in microtubule (mt) and f-actin architecture downstream of guidance cues. however, the mechanisms by which mts and f-actin are dually coordinated remain a fundamentally unresolved question. here, we report that the well-characterized mt polymerase, xmap215 (also known as ckap5), plays an important role in mediating mt-f-actin interaction within the growth cone. we demonstrate that xmap215 regulates mt-f-actin al ...201930890650
a microarray-based comparative analysis of gene expression profiles in thyroid glands in amphibian metamorphosis: differences in effects between chemical exposure and food restriction.tadpoles during metamorphosis are sensitive to chemical exposure as shown in the amphibian metamorphosis assay, which is a method to detect effects of chemicals on the functions of hypothalamus-pituitary-thyroid axis. the present study reports existence of different modes of action between pyriproxyfen (pyr) and 6-propyl-2-thiouracil (ptu) under different feeding conditions based on gene expression profiles (transcriptomics) in the thyroid glands of tadpoles of the african clawed frog, xenopus l ...201930883854
effect of nucleosome assembly on alkylation by a dynamic electrophile.quinone methides are reactive electrophiles that are generated during metabolism of various drugs, natural products, and food additives. their chemical properties and cellular effects have been described previously, and now their response to packaging dna in a nucleosome core is described. a model bisquinone methide precursor (bisqmp) was selected based on its ability to form reversible adducts with guanine n7 that allow for their redistribution and transfer after quinone methide regeneration. a ...201930882212
exposure to graphene oxide at environmental concentrations induces thyroid endocrine disruption and lipid metabolic disturbance in xenopus laevis.graphene oxide (go) has become a topic of increasing concern for its environmental and health risks. however, the potential toxic effects of go on wildlife remain limited. the present study chose the xenopus laevis tadpole as a model to assess the thyroid endocrine disruption as well as the lipid metabolic disturbance of go. tadpoles at the 51 stage were exposed to go (0, 0.01, 0.1, and 1 mg/l) for 21 days, when tadpoles were undergoing an extremely complicated phase of morphological changes and ...201931549672
microinjection of dna into eyebuds in xenopus laevis embryos and imaging of gfp expressing optic axonal arbors in intact, living xenopus tadpoles.the primary visual projection of tadpoles of the aquatic frog xenopus laevis serves as an excellent model system for studying mechanisms that regulate the development of neuronal connectivity. during establishment of the retino-tectal projection, optic axons extend from the eye and navigate through distinct regions of the brain to reach their target tissue, the optic tectum. once optic axons enter the tectum, they elaborate terminal arbors that function to increase the number of synaptic connect ...201931545319
characteristics of in vivo model systems for ovarian cancer studies.an understanding of the molecular pathogenesis and heterogeneity of ovarian cancer holds promise for the development of early detection strategies and novel, efficient therapies. in this review, we discuss the advantages and limitations of animal models available for basic and preclinical studies. the fruit fly model is suitable mainly for basic research on cellular migration, invasiveness, adhesion, and the epithelial-to-mesenchymal transition. higher-animal models allow to recapitulate the arc ...201931540126
colony-stimulating factor-1- and interleukin-34-derived macrophages differ in their susceptibility to mycobacterium marinum.mycobacterium tuberculosis (mtb), the causative agent of tuberculosis (tb), remains the leading global cause of death from an infectious agent. mycobacteria thrive within their host mϕs and presently, there is no animal model that permits combined in vitro and in vivo study of mycobacteria-host mϕ interactions. mycobacterium marinum (mm), which causes tb in aquatic vertebrates, has become a promising model for tb research, owing to its close genetic relatedness to mtb and the availability of alt ...201931535730
structure-function elucidation of a new α-conotoxin, milia, from conus milneedwardsi.the a-conotoxins are peptide toxins that are found in the venom of marine cone snails and they are potent antagonists of various subtypes of nicotinic acetylcholine receptors (nachrs). because nachrs have an important role in regulating transmitter release, cell excitability, and neuronal integration, nachr dysfunctions have been implicated in a variety of severe pathologies. we describe the isolation and characterization of α-conotoxin milia, the first conopeptide from the venom of conus milnee ...201931527432
enrichment of aurora b kinase at the inner kinetochore controls outer kinetochore assembly.outer kinetochore assembly enables chromosome attachment to microtubules and spindle assembly checkpoint (sac) signaling in mitosis. aurora b kinase controls kinetochore assembly by phosphorylating the mis12 complex (mis12c) subunit dsn1. current models propose dsn1 phosphorylation relieves autoinhibition, allowing mis12c binding to inner kinetochore component cenp-c. using xenopus laevis egg extracts and biochemical reconstitution, we found that autoinhibition of the mis12c by dsn1 impedes its ...201931527147
identification of shaker k+ channel family members in rosaceae and a functional exploration of pbrkat1.pbrkat1, which is inhibited by external na+ in xenopus laevis oocytes, is characterized as encoding a typical inward rectifying channel that is mainly expressed in guard cells. potassium (k+) is the most abundant cation in plant cells necessary for plant growth and development. the uptake and transport of k+ are mainly completed through transporters and channels, and the shaker family genes are the most studied k+ channels in plants. however, there is far less information about this family in ro ...201931523779
spatiotemporal expression profile of embryonic and adult ankyrin repeat and ef-hand domain containing protein 1-encoding genes ankef1a and ankef1b in zebrafish.recent human next-generation sequencing (ngs) studies indicate a correlation between ankef1 (ankyrin repeat and ef-hand domain containing protein 1) expression and cilia formation or function. additionally, a single study conducted in the african clawed frog (xenopus laevis) showed ankef1 is down-regulated after pharmacological fibroblast growth factor (fgf) inhibition and plays a role in protocadherin-mediated cell protrusion and adhesion. that study also revealed a critical role for ankef1 in ...201931520739
polyamine biosynthesis in xenopus laevis: the xlazin2/xlodc2 gene encodes a lysine/ornithine decarboxylase.ornithine decarboxylase (odc) is a key enzyme in the biosynthesis of polyamines, organic cations that are implicated in many cellular processes. the enzyme is regulated at the post-translational level by an unusual system that includes antizymes (azs) and antizyme inhibitors (azins). most studies on this complex regulatory mechanism have been focused on human and rodent cells, showing that azins (azin1 and azin2) are homologues of odc but devoid of enzymatic activity. little is known about xenop ...201931509528
identification of lysine histidine transporter 2 as an 1-aminocyclopropane carboxylic acid transporter in arabidopsis thaliana by transgenic complementation approach.1-aminocyclopropane-1-carboxylic acid (acc), a biosynthetic precursor of ethylene, has long been proposed to act as a mobile messenger in higher plants. however, little is known about the transport system of acc. recently, our genetic characterization of an acc-resistant mutant with normal ethylene sensitivity revealed that lysine histidine transporter 1 (lht1) functions as a transporter of acc. as amino acid transporters might have broad substrate specificity, we hypothesized that other amino a ...201931572413
electrophysiological studies revealed cam1-mediated regulation of the arabidopsis calcium channel cngc12.the arabidopsis cyclic nucleotide-gated channel (cngc) family consists of 20 members, which have been reported to participate in various physiological processes, such as pathogen defense, development, and thermotolerance. although cngc11 and cngc12 have been identified a decade ago and their role in programmed cell death is well studied, their precise channel regulation has not been studied electrophysiologically. here, we determined the channel activities of cngc11 and cngc12 utilizing the two- ...201931572412
in vitro reconstruction of xenopus oocyte ovulation.progesterone is widely used to induce maturation of isolated fully grown oocytes of the african clawed frog, xenopus laevis. however, the hormone fails to release oocytes from the layer of surrounding follicle cells. here, we report that maturation and follicle rupture can be recapitulated in vitro by treating isolated follicular oocytes with progesterone and low doses of the matrix metalloproteinase (mmp), collagenase, which are ineffective in the absence of the steroid. using this in vitro ovu ...201931561408
bap1 regulates epigenetic switch from pluripotency to differentiation in developmental lineages giving rise to bap1-mutant cancers.the bap1 tumor suppressor is mutated in many human cancers such as uveal melanoma, leading to poor patient outcome. it remains unclear how bap1 functions in normal biology or how its loss promotes cancer progression. here, we show that bap1 is critical for commitment to ectoderm, mesoderm, and neural crest lineages during xenopus laevis development. bap1 loss causes transcriptional silencing and failure of h3k27ac to accumulate at promoters of key genes regulating pluripotency-to-commitment tran ...201931555735
structural determinants underlying permeant discrimination of the cx43 hemichannel.connexin (cx) gap junction channels comprise two hemichannels in neighboring cells, and their permeability is well-described, but permeabilities of the single cx hemichannel remain largely unresolved. moreover, determination of isoform-specific cx hemichannel permeability is challenging because of concurrent expression of other channels with similar permeability profiles and inhibitor sensitivities. the mammalian cx hemichannels cx30 and cx43 are gated by extracellular divalent cations, removal ...201931554662
emodepside has sex-dependent immobilizing effects on adult brugia malayi due to a differentially spliced binding pocket in the rck1 region of the slo-1 k channel.filariae are parasitic nematodes that are transmitted to their definitive host as third-stage larvae by arthropod vectors like mosquitoes. filariae cause diseases including: lymphatic filariasis with distressing and disturbing symptoms like elephantiasis; and river blindness. filarial diseases affect millions of people in 73 countries throughout the topics and sub-tropics. the drugs available for mass drug administration, (ivermectin, albendazole and diethylcarbamazine), are ineffective against ...201931553770
fluorescence lifetime imaging reveals heterogeneous functional distribution of egfp expressed in xenopus oocytes.the oocytes from xenopus laevis are well known for their polarity, presenting a distinct animal and vegetal pole. other heterogeneities are less known. to study the heterogeneity of the xenopus oocyte, we expressed egfp and analyzed the protein distribution with fluorescence lifetime microscopy. the vegetal pole exhibited higher levels of fluorescence, than the animal pole. however, the fluorescence lifetimes between the two areas were indistinguishable, suggesting similar environments. in contr ...201931658452
nutrient restriction causes reversible g2 arrest in xenopus neural progenitors.nutrient status affects brain development; however, the effects of nutrient availability on neural progenitor cell proliferation in vivo are poorly understood. without food, xenopus laevis tadpoles enter a period of stasis during which neural progenitor proliferation is drastically reduced, but resumes when food becomes available. here, we investigate how neural progenitors halt cell division in response to nutrient restriction and subsequently re-enter the cell cycle upon feeding. we demonstrat ...201931649012
bioinformatics screening of genes specific for well-regenerating vertebrates reveals c-answer, a regulator of brain development and regeneration.the molecular basis of higher regenerative capacity of cold-blooded animals comparing to warm-blooded ones is poorly understood. although this difference in regenerative capacities is commonly thought to be a result of restructuring of the same regulatory gene network, we hypothesized that it may be due to loss of some genes essential for regeneration. we describe here a bioinformatic method that allowed us to identify such genes. for investigation in depth we selected one of them encoding trans ...201931644900
azi-medetomidine: synthesis and characterization of a novel α2 adrenergic photoaffinity ligand.agonists at the α2 adrenergic receptor produce sedation, increase focus, provide analgesia, and induce centrally mediated hypotension and bradycardia, yet neither their dynamic interactions with adrenergic receptors nor their modulation of neuronal circuit activity is completely understood. photoaffinity ligands of α2 adrenergic agonists have the potential both to capture discrete moments of ligand-receptor interactions and to prolong naturalistic drug effects in discrete regions of tissue in vi ...201931638765
nucleoplasmin is a limiting component in the scaling of nuclear size with cytoplasmic volume.how nuclear size is regulated relative to cell size is a fundamental cell biological question. reductions in both cell and nuclear sizes during xenopus laevis embryogenesis provide a robust scaling system to study mechanisms of nuclear size regulation. to test if the volume of embryonic cytoplasm is limiting for nuclear growth, we encapsulated gastrula-stage embryonic cytoplasm and nuclei in droplets of defined volume using microfluidics. nuclei grew and reached new steady-state sizes as a funct ...201931636119
n-glycosylation of trek-1/hk2p2.1 two-pore-domain potassium (k2p) channels.mechanosensitive htrek-1 two-pore-domain potassium (hk2p2.1) channels give rise to background currents that control cellular excitability. recently, trek-1 currents have been linked to the regulation of cardiac rhythm as well as to hypertrophy and fibrosis. even though the pharmacological and biophysical characteristics of htrek-1 channels have been widely studied, relatively little is known about their posttranslational modifications. this study aimed to evaluate whether htrek-1 channels are n- ...201931635148
an optimized screen reduces the number of ga transporters and provides insights into nitrate transporter 1/peptide transporter family substrate determinants.based on recent in vitro data, a relatively large number of the plant nitrate transporter 1/peptide transporter family (npf) proteins have been suggested to function as gibberellic acid (ga) transporters. most ga transporting npf proteins also appear to transport other structurally unrelated phytohormones or metabolites. several of the gas used in previous in vitro assays are membrane permeable weak organic acids whose movement across membranes are influenced by the ph-sensitive ion-trap mechani ...201931632416
kif2a scales meiotic spindle size in hymenochirus boettgeri.size is a fundamental feature of biological systems that affects physiology at all levels. for example, the dynamic, microtubule-based spindle that mediates chromosome segregation scales to a wide range of cell sizes across different organisms and cell types. xenopus frog species possess a variety of egg and meiotic spindle sizes, and differences in activities or levels of microtubule-associated proteins in the egg cytoplasm between xenopus laevis and xenopus tropicalis have been shown to accoun ...201931630945
spontaneous emergence of cell-like organization in xenopus egg extracts.every daughter cell inherits two things from its mother: genetic information and a spatially organized complement of macromolecular complexes and organelles. the extent to which de novo self-organization, as opposed to inheritance of an already organized state, can suffice to yield functional cells is uncertain. we used xenopus laevis egg extracts to show that homogenized interphase egg cytoplasm self-organizes over the course of ~30 minutes into compartments 300 to 400 micrometers in length tha ...201931672897
single-cell proteomics in complex tissues using microprobe capillary electrophoresis mass spectrometry.direct measurement of proteins produced by single cells promises to expand our understanding of molecular cell-to-cell differences (heterogeneity) and their contribution to normal and impaired development. high-resolution mass spectrometry (hrms) is the modern technology of choice for the label-free identification and quantification of proteins, albeit usually in large populations of cells. recent advances in microscale sample collection and processing, separation, and ionization have extended t ...201931668233
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