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on the mechanism of the electrophysiological changes and membrane lesions induced by asbestos fiber exposure in xenopus laevis oocytes.the so-called amphibole asbestos fibers are enriched with mineral iron ions, able to stimulate ros production. we recently reported that crocidolite asbestos was able to interact with the cell membranes of xenopus laevis oocytes, to alter their electrical membrane properties. here, we found that applied iron ions (fe3+) or h2o2 (for ros generation) mimicked these effects, suggesting that at least one effect of iron-containing asbestos fiber exposure was mediated by ros production. furthermore, c ...201930765791
wgddetector: a pipeline for detecting whole genome duplication events using the genome or transcriptome annotations.with the availability of well-assembled genomes of a growing number of organisms, identifying the bioinformatic basis of whole genome duplication (wgd) is a growing field of genomics. the most extant software for detecting footprints of wgds has been restricted to a well-assembled genome. however, the massive poor quality genomes and the more accessible transcriptomes have been largely ignored, and in theoretically they are also likely to contribute to detect wgd using ds based method. here, to ...201930760221
analysis of long non-coding rna involved in atrazine-induced testicular degeneration of xenopus laevis.long non-coding rna (lncrna) plays a critical role in male germline development. atrazine (az) as an environmental endocrine disrupting chemical (edcs) can induce male reproductive toxicity in amphibians. our previous studies demonstrated that az can alter gene and circular rna (circrna) expression of damaged testes in xenopus laevis (x. laevis). we furthered to investigate the lncrna expression profiling in the testis of x. laevis. over 3559 lncrnas were detected by lncrna sequencing. az induce ...201930675760
oscillating aquaporin phosphorylation and 14-3-3 proteins mediate the circadian regulation of leaf hydraulics.the circadian clock regulates plant tissue hydraulics to synchronize water supply with environmental cycles and thereby optimize growth. the circadian fluctuations in aquaporin transcript abundance suggest that aquaporin water channels play a role in these processes. here, we show that hydraulic conductivity (kros) of arabidopsis (arabidopsis thaliana) rosettes displays a genuine circadian rhythmicity with a peak around midday. combined immunological and proteomic approaches revealed that phosph ...201930674691
non-acylated wnts can promote signaling.wnts are a family of 19 extracellular ligands that regulate cell fate, proliferation, and migration during metazoan embryogenesis and throughout adulthood. wnts are acylated post-translationally at a conserved serine and bind the extracellular cysteine-rich domain (crd) of frizzled (fzd) seven-pass transmembrane receptors. although crystal structures suggest that acylation is essential for wnt binding to fzds, we show here that several wnts can promote signaling in xenopus laevis and danio rerio ...201930673610
effect of the flavonoid hesperidin on glucose and fructose transport, sucrase activity and glycaemic response to orange juice in a crossover trial on healthy volunteers.although polyphenols inhibit glucose absorption and transport in vitro, it is uncertain whether this activity is sufficient to attenuate glycaemic response in vivo. we examined this using orange juice, which contains high levels of hesperidin. we first used a combination of in vitro assays to evaluate the potential effect of hesperidin and other orange juice components on intestinal sugar absorption and then tested whether this translated to an effect in healthy volunteers. hesperidin attenuated ...201930670104
whole-cell photoacoustic sensor based on pigment relocalization.photoacoustic (optoacoustic) imaging can extract molecular information with deeper tissue penetration than possible by fluorescence microscopy techniques. however, there is currently still a lack of robust genetically controlled contrast agents and molecular sensors that can dynamically detect biological analytes of interest with photoacoustics. in a biomimetic approach, we took inspiration from cuttlefish who can change their color by relocalizing pigment-filled organelles in so-called chromato ...201930663315
the cmg helicase bypasses dna-protein cross-links to facilitate their repair.covalent dna-protein cross-links (dpcs) impede replication fork progression and threaten genome integrity. using xenopus egg extracts, we previously showed that replication fork collision with dpcs causes their proteolysis, followed by translesion dna synthesis. we show here that when dpc proteolysis is blocked, the replicative dna helicase cmg (cdc45, mcm2-7, gins), which travels on the leading strand template, bypasses an intact leading strand dpc. single-molecule imaging reveals that gins doe ...201930595447
xenopus laevis fgf16 activates the expression of genes coding for the transcription factors sp5 and sp5l.fibroblast growth factors (fgfs) comprise a family of signalling molecules with essential roles in early embryonic development across animal species. the role of fgfs in mesoderm formation and patterning in xenopus has been particularly well studied. however, little is known about fgf16 in xenopus. using in situ hybridisation, we uncover the expression pattern of fgf16 during early xenopus laevis development, which has not been previously described. we show that the zygotic expression of fgf16 i ...201932149373
rhinella marina oocytes: a suitable alternative expression system for functional characterization of aquaglyceroporins.amphibian oocytes have been extensively used for heterologous expression of membrane proteins for studying their biochemical and biophysical properties. so far, xenopus laevis is the main amphibian used as oocytes source to express aquaglyceroporins in order to assess water and solutes permeability. however, this well-established amphibian model represents a threat to the biodiversity in many countries, especially in those from tropical regions. for that reason, the import of xenopus laevis is s ...201930631140
identification of vacuolar phosphate efflux transporters in land plants.inorganic phosphate (pi) is an essential component of all life forms. land plants acquire pi from the soil through roots and associated symbioses, and it is then transported throughout the plant. when sufficient, excess pi is stored in vacuoles for remobilization following pi deficiency. although pi release from the vacuoles to the cytoplasm serves as a critical mechanism for plants to adapt to low-pi stress, the transporters responsible for vacuolar pi efflux have not been identified. here, we ...201930626920
cdk phosphorylation of xenopus laevis m18bp1 promotes its metaphase centromere localization.chromosome segregation requires the centromere, the site on chromosomes where kinetochores assemble in mitosis to attach chromosomes to the mitotic spindle. centromere identity is defined epigenetically by the presence of nucleosomes containing the histone h3 variant cenp-a. new cenp-a nucleosome assembly occurs at the centromere every cell cycle during g1, but how cenp-a nucleosome assembly is spatially and temporally restricted remains poorly understood. centromere recruitment of factors requi ...201930606714
probing the dynamics and structural topology of the reconstituted human kcnq1 voltage sensor domain (q1-vsd) in lipid bilayers using electron paramagnetic resonance spectroscopy.kcnq1 (kv7.1 or kvlqt1) is a potassium ion channel protein found in the heart, ear, and other tissues. in complex with the kcne1 accessory protein, it plays a role during the repolarization phase of the cardiac action potential. mutations in the channel have been associated with several diseases, including congenital deafness and long qt syndrome. nuclear magnetic resonance (nmr) structural studies in detergent micelles and a cryo-electron microscopy structure of kcnq1 from xenopus laevis have s ...201930620191
immunohistochemical localization of calpains in the amphibian xenopus laevis.though histochemical techniques have been used for decades, they are still very important in basic research. they make it possible to work on fixed tissues and provide a large amount of information in a relatively short time and at a low cost. here we describe methods for indirect immunohistochemistry and immunofluorescence on sections of tadpoles and tissues of adult amphibians belonging to the species xenopus laevis. the objective is to localize calpains within tissues in order to understand t ...201930617797
applications of in-cell nmr in structural biology and drug discovery.in-cell nuclear magnetic resonance (nmr) is a method to provide the structural information of a target at an atomic level under physiological conditions and a full view of the conformational changes of a protein caused by ligand binding, post-translational modifications or protein⁻protein interactions in living cells. previous in-cell nmr studies have focused on proteins that were overexpressed in bacterial cells and isotopically labeled proteins injected into oocytes of xenopus laevis or delive ...201930609728
curare alkaloids from matis dart poison: comparison with d-tubocurarine in interactions with nicotinic, 5-ht3 serotonin and gabaa receptors.several novel bisbenzylisoquinoline alkaloids (bbiqas) have recently been isolated from a matis tribe arrow poison and shown by two-electrode voltage-clamp to inhibit mouse muscle nicotinic acetylcholine receptors (nachr). here, using radioligand assay with aplysia californica achbp and radioiodinated α-bungarotoxin ([125i]-αbgt), we show that bbiqa1, bbiqa2, and d-tubocurarine (d-tc) have similar affinities to nachr orthosteric site. however, a competition with [125i]-αbgt for binding to the to ...201930608952
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
xenopus oocytes as a heterologous expression system for analysis of tight junction proteins.claudins (cldns) represent the largest family of transmembrane tight junction (tj) proteins, determining organ-specific epithelial barrier properties. because methods for the analysis of multiple cldn interaction are limited, we have established the heterologous xenopus laevis oocyte expression system for tj protein assembly and interaction analysis. oocytes were injected with crna encoding human cldn-1, -2, or -3 or with a combination of these and were incubated in pairs for interaction analysi ...201930645152
insemination or phosphatidic acid induces an outwardly spiraling disk of elevated ca2+ to produce the ca2+ wave during xenopus laevis fertilization.during xenopus fertilization, the initial intracellular calcium ((ca2+)i) release at the sperm-egg binding site (hot spot) has not been described without the use of inhibitors, nor related to underlying er structure. without inhibitors, we now report that sperm induce an initial hot spot after sperm addition to xenopus eggs that was ~25 µm. this area is consistent with the size of er patches and clusters of ip3 receptors that have enhanced activity. furthermore, we find a new mechanism for the f ...201930641042
ensa and arpp19 differentially control cell cycle progression and development.greatwall (gwl) is an essential kinase that indirectly controls pp2a-b55, the phosphatase counterbalancing cyclin b/cdk1 activity during mitosis. in xenopus laevis egg extracts, gwl-mediated phosphorylation of overexpressed arpp19 and ensa turns them into potent pp2a-b55 inhibitors. it has been shown that the gwl/ensa/pp2a-b55 axis contributes to the control of dna replication, but little is known about the role of arpp19 in cell division. by using conditional knockout mouse models, we investiga ...201930626720
xenopus slc7a5 is essential for notochord function and eye development.slc7a5 (also known as lat1), largely accepted as an amino acid transporter, has been shown to play important roles in cancer and developmental processes. because knockout mice of slc7a5 are embryonically lethal due to placental defects, it is difficult to evaluate its role in early development. in this study, expression and function of slc7a5 were evaluated in xenopus laevis embryos that develop without a placenta. expression of slc7a5 was detected in the notochord and in the eye and it was not ...201930625369
reinterpretation of the substrate specificity of the voltage-sensing phosphatase during dimerization.voltage-sensing phosphatases (vsps) cleave both 3- and 5-phosphates from inositol phospholipids in response to membrane depolarization. when low concentrations of ciona intestinalis vsp are expressed in xenopus laevis oocytes, the 5-phosphatase reaction can be observed during large membrane depolarizations. when higher concentrations are expressed, the 5-phosphatase activity is observed with smaller depolarizations, and the 3-phosphatase activity is revealed with strong depolarization. here we a ...201930622132
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
skin grafting in xenopus laevis: a technique for assessing development and immunological disparity.skin grafting in the amphibian xenopus laevis has been used to detect not only allogeneic antigens that differ by minor h antigens or by one mhc haplotype, but also to detect ontogeny-specific antigens (including both emerging adult- and disappearing larval-specific) during metamorphosis. to understand the mechanisms underlying allogeneic tolerance or immune responses against larval- and/or adult-specific antigens, a complete mhc homozygous, inbred strain is the most appropriate experimental mod ...201930606753
methodological improvements for fluorescence recordings in xenopus laevis oocytes.xenopus laevis oocytes are a widely used model system because of their capacity to translate exogenous mrna, but their high intrinsic background fluorescence is a disadvantage for fluorescence recordings. here, we developed two distinct methods for improving fluorescence recordings from oocytes. one was a pharmacological method in which a small-molecule salt-inducible kinase inhibitor was co-injected with the mrna of interest to stimulate melanin production. we interrogated the oocytes using cut ...201930606741
αd-conotoxins in species of the eastern pacific: the case of conus princeps from mexico.conus snails produce venoms containing numerous peptides such as the α-conotoxins (α-ctxs), which are well-known nicotinic acetylcholine receptor (nachr) antagonists. thirty-eight chromatographic fractions from conus princeps venom extract were isolated by rp-hplc. the biological activities of 37 fractions (0.07 µg/µl) were assayed by two-electrode voltage clamp on human α7 nachrs expressed in xenopus laevis oocytes. fractions f7 and f16 notably inhibited the response elicited by acetylcholine b ...201931336928
neuroendocrine modulation of predator avoidance/prey capture tradeoffs: role of tectal npy2r receptors.the optic tectum rapidly inhibits food intake when a visual threat is present. anatomical and electrophysiological evidence support a role for neuropeptide y (npy), originating from cells in the thalamus, in the tectal inhibition of prey capture. here we test the hypothesis that tectal npy receptor type 2 (npy2r) influences prey-capture and predator-avoidance responses in the african clawed frog, xenopus laevis. we tested two questions: 1) does tectal npy administration decrease food intake and ...201931271760
impact of 4-aminopyridine on vestibulo-ocular reflex performance.vestibulo-ocular reflexes (vor) are mediated by frequency-tuned pathways that separately transform the different dynamic and static aspects of head motion/position-related sensory signals into extraocular motor commands. voltage-dependent potassium conductances such as those formed by kv1.1 are important for the ability of vor circuit elements to encode highly transient motion components. here we describe the impact of the kv1.1 channel blocker 4-aminopyridine (4-ap) on spontaneous and motion-ev ...201931270663
data demonstrating distinct embryonic developmental defects induced by bisphenol a alternatives.embryos of xenopus laevis (african clawed frog) were exposed to the widespread environmental plasticizers bisphenol af (bpaf; 0.003-3 μm), bisphenol a (bpa; 1-50 μm), or 17β-estradiol (e2; 10 μm) from just after fertilization through 96 hours of development. the potencies and cellular and morphological effects were compared across chemical treatments and controls. the embryos were staged, counted and imaged, and time-lapse movies collected, on an inverted stereomicroscope and camera. the data sh ...201931249853
an extracellular acidic cleft confers profound h+-sensitivity to epithelial sodium channels containing the δ-subunit in xenopus laevis.the limited sodium availability of freshwater and terrestrial environments was a major physiological challenge during vertebrate evolution. the epithelial sodium channel (enac) is present in the apical membrane of sodium-absorbing vertebrate epithelia and evolved as part of a machinery for efficient sodium conservation. enac belongs to the degenerin/enac protein family and is the only member that opens without an external stimulus. we hypothesized that enac evolved from a proton-activated sodium ...201931248986
commentary on classic paper "gimlich, r.l., gerhart, j.c., 1984. early cellular interactions promote embryonic axis formation in xenopus laevis. dev biol 104, 117-130." 201931235010
catalyst-free click pegylation reveals substantial mitochondrial atp synthase sub-unit alpha oxidation before and after fertilisation.using non-reducing western blotting to assess protein thiol redox state is challenging because most reduced and oxidised forms migrate at the same molecular weight and are, therefore, indistinguishable. while copper catalysed click chemistry can be used to ligate a polyethylene glycol (peg) moiety termed click pegylation to mass shift the reduced or oxidised form as desired, the potential for copper catalysed auto-oxidation is problematic. here we define a catalyst-free trans-cyclooctene-methylt ...201931234016
single cell proteomics by data-independent acquisition to study embryonic asymmetry in xenopus laevis.techniques that allow single cell analysis are gaining widespread attention, and most of these studies utilize genomics-based approaches. while nanofluidic technologies have enabled mass spectrometric analysis of single cells, these measurements have been limited to metabolomics and lipidomic studies. single cell proteomics has the potential to improve our understanding of intercellular heterogeneity. however, this approach has faced challenges including limited sample availability, as well as a ...201931194517
injection of mrna isolated from trophozoites of giardia intestinalis induces expression of three types of chloride currents in xenopus laevis oocytes.giardia lamblia is one of the most important worldwide causes of intestinal infections, yet little is known about its cellular physiology, especially the diversity of ionic channels that this parasite expresses. in this work, we show that injection of mrna isolated from trophozoites of giardia, into xenopus laevis oocytes, induces expression of three types of chloride currents (here referred to as icl-g1, icl-g2, and icl-g3), which have different biophysical and pharmacological properties. icl-g ...201931187589
impacts of the mhc class i-like xnc10 and innate-like t cells on tumor tolerance and rejection in the amphibian xenopus.the conditions that lead to antitumor or protumor functions of natural killer t (nkt) cells against mammalian tumors are only partially understood. therefore, insights into the evolutionary conservation of nkt and their analogs-innate-like t (it) cells-may reveal factors that contribute to tumor eradication. as such, we investigated the amphibian xenopus laevis it cells and interacting mhc class i-like (xnc or mhc1b.l) genes against ff-2 thymic lymphoid tumors. upon ff-2 intraperitoneal transpla ...201931155639
involvement of myt1 kinase in the g2 phase of the first cell cycle in xenopus laevis.during cleavage of xenopus laevis, the first mitotic cell cycle immediately following fertilization is approximately 90 min and consists of s, g2, and m phases. in contrast, the subsequent eleven cell cycles are approximately 30 min and consist mostly of s and m phases. the balance between cdc25 and wee1a/myt1 is thought to be crucial for xenopus first cell cycle progression; however, the role of myt1 in this period has not been fully investigated. in this study, we examined the roles of myt1, w ...201931128913
the direct permeation of nanoparticles through the plasma membrane transiently modifies its properties.the exposure to metal nanoparticles (nps) has increased with their widespread use in industry, research and medicine. it is well known that nps may enter cells and that this mechanism is crucial to exert both the therapeutic and toxicity effects. the main cellular entrance route is endocytosis-based, however, recent experimental studies, have reported that nps can also enter the cell crossing directly the plasma membrane, it is thus important to investigate this alternative internalization mecha ...201931150635
impacts of the synthetic androgen trenbolone on gonad differentiation and development - comparisons between three deeply diverged anuran families.using a recently developed approach for testing endocrine disruptive chemicals (edcs) in amphibians, comprising synchronized tadpole exposure plus genetic and histological sexing of metamorphs in a flow-through-system, we tested the effects of 17β-trenbolone (tb), a widely used growth promoter in cattle farming, in three deeply diverged anuran families: the amphibian model species xenopus laevis (pipidae) and the non-models bufo(tes) viridis (bufonidae) and hyla arborea (hylidae). trenbolone was ...201931270347
a sclerocornea-associated rad21 variant induces corneal stroma disorganization.sclerocornea is a cornea opacification disorder. disorganized corneal stroma fibrils are observed in patients' cornea. previously we identified a rad21c1348t variant that is associated with a peripheral sclerocornea pedigree. to explore whether this rad21 variant can induce sclerocornea-related phenotype, and to investigate the possible mechanisms of such phenotype, the orthologous rad21 wild-type and variant mrnas were injected into xenopus laevis embryos and the developed eyes were subjected f ...201931173765
ism1 regulates nodal signaling and asymmetric organ morphogenesis during development.isthmin1 (ism1) was originally identified as a fibroblast group factor expressed in xenopus laevis embryonic brain, but its biological functions remain unclear. the spatiotemporal distribution of ism1, with high expression in the anterior primitive streak of the chick embryo and the anterior mesendoderm of the mouse embryo, suggested that ism1 may regulate signaling by the nodal subfamily of tgb-β cytokines that control embryo patterning. we report that ism1 is an inhibitor of nodal signaling. i ...201931171630
mortality, teratogenicity and growth inhibition of three glyphosate formulations using frog embryo teratogenesis assay-xenopus.ample evidence around the world exists suggesting a link between exposure to glyphosate, toxicity and perturbed physiological functions in non-target organisms. although glyphosate formulations are widely used for weed and alien plant management, their ecotoxicological information remain scanty. using the 96-hour frog embryo teratogenesis assay-xenopus protocol, embryotoxicity and teratogenicity of three glyphosate-based formulations were assessed. embryos of xenopus laevis were exposed to round ...201931168868
developmentally regulated gtp-binding protein 1 modulates ciliogenesis via an interaction with dishevelled.cilia are critical for proper embryonic development and maintaining homeostasis. although extensively studied, there are still significant gaps regarding the proteins involved in regulating ciliogenesis. using the xenopus laevis embryo, we show that dishevelled (dvl), a key wnt signaling scaffold that is critical to proper ciliogenesis, interacts with drg1 (developmentally regulated gtp-binding protein 1). the loss of drg1 or disruption of the interaction with dvl reduces the length and number o ...201931270137
the plus maze and scototaxis test are not valid behavioral assays for anxiety assessment in the south african clawed frog.there are no behavioral models for testing anxiety in amphibians, a group of animals widely used for developmental, ecotoxicological, and genetic research. we aimed to validate two common rodent paradigms, the plus maze and the scototaxis test, for use in the aquatic african clawed frog (xenopus laevis). we predicted: (a) that frogs would prefer the dark, vs. light, portions of the testing arenas (face validity), (b) that this behavior could be altered with acute administration of anxio-selectiv ...201931144017
acclimation temperature effects on locomotor traits in adult aquatic anurans (x. tropicalis and x. laevis) from different latitudes: possible implications for climate change.climate change is in part responsible for the 70% decline in amphibian species numbers worldwide. although temperature is expected to impact whole-organism performance in ectotherms, reversible thermal acclimation has been suggested as a mechanism that may buffer responses to abrupt temperature changes. here, we test for an effect of acclimation on locomotor performance traits (jump force and stamina) in adults of two predominantly aquatic and closely related frog species from different climatic ...201931139411
using the xenopus developmental eye regrowth system to distinguish the role of developmental versus regenerative mechanisms.a longstanding challenge in regeneration biology is to understand the role of developmental mechanisms in restoring lost or damaged tissues and organs. as these body structures were built during embryogenesis, it is not surprising that a number of developmental mechanisms are also active during regeneration. however, it remains unclear whether developmental mechanisms act similarly or differently during regeneration as compared to development. since regeneration is studied in the context of matu ...201931139088
preserving genome integrity during the early embryonic dna replication cycles.during the very early stages of embryonic development chromosome replication occurs under rather challenging conditions, including a very short cell cycle, absence of transcription, a relaxed dna damage response and, in certain animal species, a highly contracted s-phase. this raises the puzzling question of how the genome can be faithfully replicated in such a peculiar metabolic context. recent studies have provided new insights into this issue, and unveiled that embryos are prone to accumulate ...201931137726
growth at cold temperature increases the number of motor neurons to optimize locomotor function.during vertebrate development, spinal neurons differentiate and connect to generate a system that performs sensorimotor functions critical for survival. spontaneous ca2+ activity regulates different aspects of spinal neuron differentiation. it is unclear whether environmental factors can modulate this ca2+ activity in developing spinal neurons to alter their specialization and ultimately adjust sensorimotor behavior to fit the environment. here, we show that growing xenopus laevis embryos at col ...201931130453
genome wide decrease of dna replication eye density at the midblastula transition of xenopus laevis.during the first rapid divisions of early development in many species, the dna:cytoplasm ratio increases until the midblastula transition (mbt) when transcription resumes and cell cycles lengthen. s phase is very rapid in early embryos, about 20-30 times faster than in differentiated cells. using a combination of dna fiber studies and a xenopus laevis embryonic in vitro replication system, we show that s phase slows down shortly after the mbt owing to a genome wide decrease of replication eye de ...201931130065
the effect of xenopus laevis egg extracts with/without brg1 on the development of preimplantation cloned mouse embryos.summarymuch effort has been devoted to improving the efficiency of animal cloning. the aim of this study was to investigate the effect of brg1 contained in xenopus egg extracts on the development of cloned mouse embryos. the results showed that mouse nih/3t3 cells were able to express pluripotent genes after treatment with egg extracts, indicating that the egg extracts contained reprogramming factors. after co-injection of xenopus egg extracts and single mouse cumulus cells into enucleated mouse ...201931182178
dspe-peg modification of α-conotoxin txid.in order to improve stability of a peptide marine drug lead, α-conotoxin txid, we synthesized and modified txid at the n-terminal with dspe-peg-nhs by a nucleophilic substitution reaction to prepare the dspe-peg-txid for the first time. the reaction conditions, including solvent, ratio, ph, and reaction time, were optimized systematically and the optimal one was reacted in dimethyl formamide at ph 8.2 with triethylamine at room temperature for 120 h. the in vitro stabilities in serum, simulated ...201931181805
ecotoxicity of nanomaterials in amphibians: a critical review.nanomaterials (nms) have been used in a growing number of commercial products, and their rapid expansion could lead to their release into the aquatic environments. however, there is limited knowledge about the impact of nms in the biota, especially the amphibians. the present study revised the historical use of amphibian species as a model system for nanoecotoxicological studies and summarized the data available in the scientific literature about the genotoxic, mutagenic, histopathological, embr ...201931181520
disassembly of actin and keratin networks by aurora b kinase at the midplane of cleaving xenopus laevis eggs.the large length scale of xenopus laevis eggs facilitates observation of bulk cytoplasm dynamics far from the cortex during cytokinesis. the first furrow ingresses through the egg midplane, which is demarcated by chromosomal passenger complex (cpc) localized on microtubule bundles at the boundary between asters. using an extract system, we found that local kinase activity of the aurora b kinase (aurkb) subunit of the cpc caused disassembly of f-actin and keratin between asters and local softenin ...201931178324
organic anion-transporting polypeptide 1a4-mediated heterogeneous distribution of sulforhodamine-101 in rat hepatic lobules.it has been known that organic anion-transporting polypeptides (oatps) involve hepatic transports several organic anionic compounds and drugs. this study aimed to investigate sulforhodamine-101 (sr-101) distribution in the rat liver, determine the molecules responsible for the distribution, and delineate the manner of distribution. after intravenous sr-101 administration, its distribution in frozen rat hepatic sections was examined. sr-101-derived signals were detected in regions around the hepa ...201931174976
methods for studying dna single-strand break repair and signaling in xenopus laevis egg extracts.dna single-strand breaks (ssbs) are the most common type of dna lesions as they are generated approximately 10,000 times per mammalian cell each day. unrepaired ssbs compromise dna replication and transcription programs, leading to genome instability, and have been implicated in many diseases including cancer. in this chapter, we introduce methods to study the atr-chk1 dna damage response (ddr) pathway and dna repair pathway in response to a site-specific, defined ssb plasmid in xenopus laevis e ...201931127575
ptk7 proteolytic fragment proteins function during early xenopus development.protein tyrosine kinase 7 (ptk7) is as a critical regulator of canonical and non-canonical wnt-signaling during embryonic development and cancer cell formation. disrupting ptk7 activity perturbs vertebrate nervous system development, and also promotes human cancer formation. observations in different model systems suggest a complex cross-talk between ptk7 protein and wnt signaling. during xenopus laevis nervous system development, we previously showed that ptk7 protein positively regulates canon ...201931125531
development of an in vitro diagnostic method to determine the genotypic sex of xenopus laevis.a genotypic sex determination assay provides accurate gender information of individuals with well-developed phenotypic characters as well as those with poorly developed or absent of phenotypic characters. determination of genetic sex for xenopus laevis can be used to validate the outcomes of tier 2 amphibian assays, and is a requirement for conducting the larval amphibian growth and development assay (lagda), in the endocrine disruptor screening program (edsp), test guidelines. the assay we deve ...201931106075
composition and endocrine effects of water collected in the kibale national park in uganda.pesticides are used worldwide with potential harmful effects on both fauna and flora. the kibale national park in uganda, a site renowned for its biodiversity is surrounded by tea, banana and eucalyptus plantations as well as maize fields and small farms. we previously showed presence of pesticides with potential endocrine disruptive effects in the vicinity. to further investigate the water pollution linked to agricultural pressure in this protected area, we implemented a complementary monitorin ...201931103006
cardiotoxicity in african clawed frog (xenopus laevis) sub-chronically exposed to environmentally relevant atrazine concentrations: implications for species survival.the toxic effects of different atrazine concentrations on tadpoles and adult male african clawed frogs (xenopus laevis) were assessed in a controlled laboratory environment following 90 days' exposure. the aim was to elucidate the danger of atrazine exposure on the cardiac tissue relative to its critical function of rhythmic contractility, fundamental for optimal blood circulation and homeostasis. tadpoles and adult frogs were exposed to 0 μg/l (control), 0.01 μg l-1, 200 μg l-1 and 500 μg l-1 c ...201931203168
peia-5466: a novel peptide antagonist containing non-natural amino acids that selectively targets α3β2 nicotinic acetylcholine receptors.pharmacologically distinguishing α3β2 nicotinic acetylcholine receptors (nachrs) from closely related subtypes, particularly α6β2, has been challenging due to the lack of subtype-selective ligands. we created analogs of α-conotoxin (α-ctx) peia to identify ligand-receptor interactions that could be exploited to selectively increase potency and selectivity for α3β2 nachrs. a series of peia analogs were synthesized by replacing amino acid residues in the second disulfide loop with standard or nons ...201931194549
identification of a regeneration-organizing cell in the xenopus tail.unlike mammals, xenopus laevis tadpoles have a high regenerative potential. to characterize this regenerative response, we performed single-cell rna sequencing after tail amputation. by comparing naturally occurring regeneration-competent and -incompetent tadpoles, we identified a previously unrecognized cell type, which we term the regeneration-organizing cell (roc). rocs are present in the epidermis during normal tail development and specifically relocalize to the amputation plane of regenerat ...201931097661
embryonic expression of gins members in the development of the mammalian nervous system.the gins (go, ichi, nii, and san) complex contains four protein subunits (psf1, psf2, psf3, and sld5) and has been identified as a factor essential for the initiation and elongation stages of the dna replication process. a previous study indicated that psf2 participated in the developing central nervous system (cns) of xenopus laevis. however, the expression and function of gins members in the mammalian developing nervous system remains unclear. here, we examined the expression of gins members i ...201931095979
a ywhaz variant associated with cardiofaciocutaneous syndrome activates the raf-erk pathway.cardiofaciocutaneous (cfc) syndrome is a genetic disorder characterized by distinctive facial features, congenital heart defects, and skin abnormalities. several germline gain-of-function mutations in the ras/raf/mek/erk pathway are associated with the disease, including kras, braf, mek1, and mek2. cfc syndrome thus belongs to a group of disorders known as rasopathies, which are all caused by pathogenic mutations in various genes encoding components of the ras pathway. we recently identified nov ...201931024343
spindle-f-actin interactions in mitotic spindles in an intact vertebrate epithelium.mitotic spindles are well known to be assembled from and dependent on microtubules. in contrast, whether actin filaments (f-actin) are required for or are even present in mitotic spindles has long been controversial. here we have developed improved methods for simultaneously preserving f-actin and microtubules in fixed samples and exploited them to demonstrate that f-actin is indeed associated with mitotic spindles in intact xenopus laevis embryonic epithelia. we also find that there is an "f-ac ...201931091161
phosphatidylinositol 4,5-bisphosphate (pip2) and ca2+ are both required to open the cl- channel tmem16a.transmembrane member 16a (tmem16a) is a widely expressed ca2+-activated cl- channel with various physiological functions ranging from mucosal secretion to regulating smooth muscle contraction. understanding how tmem16a controls these physiological processes and how its dysregulation may cause disease requires a detailed understanding of how cellular processes and second messengers alter tmem16a channel gating. here we assessed the regulation of tmem16a gating by recording ca2+-evoked cl- current ...201931266809
dyrk1a-related intellectual disability: a syndrome associated with congenital anomalies of the kidney and urinary tract.haploinsufficiency of dyrk1a causes a recognizable clinical syndrome. the goal of this paper is to investigate congenital anomalies of the kidney and urinary tract (cakut) and genital defects (gd) in patients with dyrk1a variants.201931263215
functional characterization of smn evolution in mouse models of sma.spinal muscular atrophy (sma) is a monogenic neurodegenerative disorder and the leading genetic cause of infantile mortality. while several functions have been ascribed to the smn (survival motor neuron) protein, their specific contribution to the disease has yet to be fully elucidated. we hypothesized that some, but not all, smn homologues would rescue the sma phenotype in mouse models, thereby identifying disease-relevant domains. using aav9 to deliver smn homologs to sma mice, we identified a ...201931263170
comparative analysis of p4ha1 and p4ha2 expression during xenopus laevis development.collagen prolyl 4-hydroxylases (c-p4hs) are evolutionary conserved enzymes whose activity is essential for the correct folding of stable triple helical molecules of collagen and collagen-like proteins. they play crucial roles in embryo development, connective tissue functional organization, tumor growth and metastasis. despite the important function of these enzymes, little is known about their expression during vertebrate development. in this study, we determine and compare the previously undes ...201931250915
transcriptome analysis of regeneration during xenopus laevis experimental twinning.animal embryos have the remarkable property of self-organization. over 125 years ago, hans driesch separated the two blastomeres of sea urchin embryos and obtained twins, in what was the foundation of experimental embryology. since then, embryonic twinning has been obtained experimentally in many animals. in a recent study, we developed bisection methods that generate identical twins reliably from xenopus blastula embryos. in the present study, we have investigated the transcriptome of regenerat ...201931250914
neurotoxicity and mode of action of fluralaner on honeybee apis mellifera l.fluralaner, a novel pesticide that targets the γ-aminobutyric acid (gaba) receptor (gabar) subunit of resistant to dieldrin (rdl), exhibits strong potential to be an insecticide to control agricultural insect pests. however, the risk and action of fluralaner to economic insects, e.g., honeybee apis mellifera linnaeus, remains unclear.201931081291
xenopus resources: transgenic, inbred and mutant animals, training opportunities, and web-based support.two species of the clawed frog family, xenopus laevis and x. tropicalis, are widely used as tools to investigate both normal and disease-state biochemistry, genetics, cell biology, and developmental biology. to support both frog specialist and non-specialist scientists needing access to these models for their research, a number of centralized resources exist around the world. these include centers that hold live and frozen stocks of transgenic, inbred and mutant animals and centers that hold mol ...201931073289
pdgf-b: the missing piece in the mosaic of pdgf family role in craniofacial development.the platelet-derived growth factor (pdgf) family consists of four ligands (pdgf-a, pdgf-b, pdgf-c, pdgf-d) and two tyrosine kinase receptors (pdgfr-α and pdgfr-β). in vertebrates, pdgf signaling influences cell proliferation, migration, and matrix deposition, and its up-regulation is implicated in cancer progression. despite this evidence, the role of each family member during embryogenesis is still incomplete and partially controversial. in particular, study of the role of pdgf signaling during ...201931070827
the c-type atp-binding cassette transporter osabcc7 is involved in the root-to-shoot translocation of arsenic in rice.rice is a major dietary source of inorganic arsenic (as), a nonthreshold carcinogen. reducing as accumulation in rice grain is of critical importance for food safety. in the present study, we investigated the role of a member of the rice c-type atp-binding cassette (abc) transporter (osabcc) family, osabcc7, in arsenite [as(iii)] accumulation in rice. quantitative real-time rt-pcr showed that osabcc7 was expressed intensively in the roots and the expression was strongly suppressed by as(iii) exp ...201931028396
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
effects of nonylphenols on embryonic development and metamorphosis of xenopus laevis: fetax and amphibian metamorphosis toxicity test (oecd tg231).nonylphenols (nps) are a group of endocrine-disrupting surfactants that mimic estrogen. to determine the developmental toxicity and thyroid-disrupting effect of nps, the effects of exposure to nonylphenol (np), 4-nonylphenol (4-np), and nonylphenol ethoxylate (np-12) were examined according to the frog embryo teratogenesis assay-xenopus (fetax) and organization for economic co-operation and development test guidelines 231 (tg231). in fetax, the lc50 values of np, 4-np, and np-12 were 59.14 mg/l, ...201931022611
slpi inhibits atp-mediated maturation of il-1β in human monocytic leukocytes: a novel function of an old player.interleukin-1β (il-1β) is a potent, pro-inflammatory cytokine of the innate immune system that plays an essential role in host defense against infection. however, elevated circulating levels of il-1β can cause life-threatening systemic inflammation. hence, mechanisms controlling il-1β maturation and release are of outstanding clinical interest. secretory leukocyte protease inhibitor (slpi), in addition to its well-described anti-protease function, controls the expression of several pro-inflammat ...201931019507
special considerations for making explants and transplants with xenopus tropicalis.although xenopus laevis is an important model organism for embryological experimentation, the smaller, more genetically tractable, and faster developing xenopus tropicalis provides advantages for using genetic approaches to understand developmental mechanisms. explant cultures and transplants of x. tropicalis embryonic tissues present unique opportunities to examine embryonic tissue determination in a simplified setting. here we demonstrate preparation of explants and transplants of preplacodal ...201931010887
identification of the catechin uptake transporter responsible for intestinal absorption of epigallocatechin gallate in mice.many studies have shown that epigallocatechin gallate (egcg) contribute to the health benefits of green tea, although its bioavailability is usually low. however, the mechanism underlying its intestinal absorption remains unclear. in human subjects, it has been reported that the bioavailability of egcg increases after repeated oral catechin intake. we hypothesized that a certain uptake transporter was involved in this increase, and investigated a novel egcg transporter. we first confirmed the in ...201931358798
effects of cis-bifenthrin enantiomers on the growth, behavioral, biomarkers of oxidative damage and bioaccumulation in xenopus laevis.chirality should be taken into consideration when assessing the effect of synthetic pyrethroids to aquatic environmental safety. in our study, 96 h acute toxicity assay showed that enantiomers of cis-bf had an addictive effect of toxicity on xenopus laevis and r-cis-bifenthrin(r-cis-bf) had higher acute toxicity than s-cis-bf. in chronic assay, r-cis-bf exerted more toxic effect on behavior and development of tadpoles than s-cis-bf, and there was also enantioselective effect of cis-bf on antioxi ...201931276910
maldi-imaging of early stage xenopus laevis embryos.xenopus laevis is an important model organism for vertebrate development. an extensive literature has developed on changes in transcript expression during development of this organism, and there is a growing literature on the corresponding protein expression changes during development. in contrast, there is very little information on changes in metabolite expression during development. we present the first maldi mass-spectrometry images of metabolites within the developing embryo. these images w ...201931357275
encephalopathies with kcnc1 variants: genotype-phenotype-functional correlations.to analyze clinical phenotypes associated with kcnc1 variants other than the progressive myoclonus epilepsy-causing variant p.arg320his, determine the electrophysiological functional impact of identified variants and explore genotype-phenotype-physiological correlations.201931353855
erratum: skin grafting in xenopus laevis: a technique for assessing development and immunological disparity. 201931371466
jmjd6a regulates gsk3β rna splicing in xenopus laevis eye development.it has been suggested that jmjd6 plays an important role in gene regulation through its demethylation or hydroxylation activity on histone and transcription factors. in addition, jmjd6 has been shown to regulate rna splicing by interaction with splicing factors. in this study, we demonstrated that jmjd6a is expressed in developing xenopus laevis eye during optic vesicle formation and retinal layer differentiation stages. knockdown of jmjd6a by an antisense morpholino resulted in eye malformation ...201931361752
reference gene validation for quantitative real-time pcr studies in amphibian kidney-derived a6 epithelial cells.quantitative real-time polymerase chain reaction is a widely used technique that relies on reference genes for the normalisation of gene expression. these reference genes are constitutively expressed and must remain stable across all samples and treatments. stability of housekeeping genes may vary and must be optimised for a specific tissue, sample or cell line. here we present a study screening for possible reference gene candidates, eef1a1, rpl8, sub1.l, clta, h4 and odc1, in the xenopus laevi ...201931333044
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
involvement of g-quadruplex regions in mammalian replication origin activity.genome-wide studies of dna replication origins revealed that origins preferentially associate with an origin g-rich repeated element (ogre), potentially forming g-quadruplexes (g4). here, we functionally address their requirements for dna replication initiation in a series of independent approaches. deletion of the ogre/g4 sequence strongly decreased the corresponding origin activity. conversely, the insertion of an ogre/g4 element created a new replication origin. this element also promoted rep ...201931332171
na3 glycan: a potential therapy for retinal pigment epithelial deficiency.atrophic age-related macular degeneration (amd) is the most common type of amd, yet there is no united states food and drug administration (fda)-approved therapy. this disease is characterized by retinal pigment epithelial (rpe) insufficiency, primarily in the macula, which affects the structure and physiology of photoreceptors and ultimately, visual function. in this study, we evaluated the protective effects of a naturally derived small molecule glycan therapeutic-asialo-, tri-antennary comple ...201931322324
structure, development, and functional morphology of the cement gland of the giant danio, devario malabaricus.aquatic species in several clades possess cement glands producing adhesive secretions of various strengths. in vertebrates, transient adhesive organs have been extensively studied in xenopus laevis, other anurans, and in several fish species. however, the development of these structures is not fully understood.201931310039
evaluating the role of fish as surrogates for amphibians in pesticide ecological risk assessment.ecological risk of chemicals to aquatic-phase amphibians has historically been evaluated by comparing estimated environmental concentrations in surface water to surrogate toxicity data from fish species. despite their obvious similarities, there are biological disparities among fish and amphibians that could affect their exposure and response to chemicals. given the alarming decline in amphibians, in which anthropogenic pollutants play at least some role, investigating the risk of chemicals to a ...201931299708
comparative embryonic spatio-temporal expression profile map of the xenopus p2x receptor family.p2x receptors are atp-gated cations channels formed by the homo or hetero-trimeric association from the seven cloned subunits (p2x1-7). p2x receptors are widely distributed in different organs and cell types throughout the body including the nervous system and are involved in a large variety of physiological but also pathological processes in adult mammals. however, their expression and function during embryogenesis remain poorly understood. here, we report the cloning and the comparative expres ...201931402854
radiographic and ultrasonographic appearance of pneumonia in a frog.a 12-year-old female african clawed frog (xenopus laevis) displayed lethargy and anorexia for 1 week. radiographs detected a moderately reduced volume of aerated lung with lobulated margins with the left lung predominantly affected. transcelomic ultrasound revealed marked consolidation of the left lung. postmortem examination confirmed suppurative and histiocytic pneumonia, worse in the left lung, caused by mycobacterium chelonae. given that amphibian pulmonary consolidation and celomic effusion ...201931392794
evolution of cis-regulatory modules for the head organizer gene goosecoid in chordates: comparisons between branchiostoma and xenopus.in cephalochordates (amphioxus), the notochord runs along the dorsal to the anterior tip of the body. in contrast, the vertebrate head is formed anterior to the notochord, as a result of head organizer formation in anterior mesoderm during early development. a key gene for the vertebrate head organizer, goosecoid (gsc), is broadly expressed in the dorsal mesoderm of amphioxus gastrula. amphioxus gsc expression subsequently becomes restricted to the posterior notochord from the early neurula. thi ...201931388442
stereoselective anti-cancer activities of ginsenoside rg3 on triple negative breast cancer cell models.ginsenoside rg3 (rg3) has two epimers, 20(s)-ginsenoside rg3 (srg3) and 20(r)-ginsenoside rg3 (rrg3), and while rg3 itself has been reported to have anti-cancer properties, few studies have been reported on the anti-cancer effects of the different epimers. the aim was to investigate the stereoselective effects of the rg3 epimers on triple negative breast cancer (tnbc) cell lines, tested using cell-based assays for proliferation, apoptosis, cell cycle arrest, migration and invasion. molecular doc ...201931374984
allocation trade-offs impact organ size and muscle architecture in an invasive population of xenopus laevis in western france.invasive species are a global scourge and often negatively impact native species. understanding the expansion and dispersal limits of these species is essential. as previous studies have demonstrated increased locomotor performance for populations at the edge of the range of expanding populations, studies of locomotion including the anatomical and physiological traits underlying dispersal capacity are of interest. we focus here on an invasive population of xenopus laevis introduced in france nea ...201931373390
novel vectors for functional interrogation of xenopus orfeome coding sequences.the current xenopus orfeome contains ~10,250 validated, full-length cdna sequences without stop codons from xenopus laevis and ~3,970 from xenopus tropicalis cloned into gateway-compatible entry vectors. to increase the utility of the orfeome, we have constructed the gateway-compatible destination vectors pdxtp and pdxtr, which in combination can control the spatial and temporal expression of any open reading frame (orf). pdxtp receives a promoter/enhancer of interest, which controls the spatial ...201931403250
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
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
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
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