Publications

TitleAbstractYear(sorted descending)
Filter
PMID
Filter
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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 xenopus tropicalis model for studies of developmental and reproductive toxicity.the reproductive cycle encompasses processes such as sex organ differentiation and development in the early life stages and maturation of the gametes in the adult organism. during the early life stages, critical developmental programming of the endocrine and reproductive systems occurs, and exposure to chemicals during these critical developmental windows can result in impaired reproductive function later in life. it is therefore important to evaluate long-term consequences of early life stage e ...201931069675
disrupted plasma membrane protein homeostasis in a xenopus laevis model of retinitis pigmentosa.rhodopsin mislocalization is frequently observed in retinitis pigmentosa (rp) patients. for example, class i mutant rhodopsin is deficient in the vxpx trafficking signal, mislocalizes to the plasma membrane (pm) of rod photoreceptor inner segments (iss), and causes autosomal dominant rp. mislocalized rhodopsin causes photoreceptor degeneration in a manner independent of light-activation. in this manuscript, we took advantage of xenopus laevis models of both sexes expressing wild-type human rhodo ...201931061086
antinociceptive effects of new pyrazoles compounds mediated by the asic-1α channel, trpv-1 and μmor receptors.pyrazoles are potent medicinal scaffolds and exhibit a wide spectrum of biological activities, such as analgesic, anti-inflammatory and antipyretic. in this paper we report on research we have performed with the aim of continuing the biological evaluation of the regio-isomeric pyrazole compounds, lqfm-020 (fluorine, para position), lqfm-021 (fluorine, meta position), and lqfm-039 (fluorine, ortho position) in models of pain induced by acidified saline, capsaicin, and formalin. we also investigat ...201931055237
isolation of nanobodies against xenopus embryonic antigens using immune and non-immune phage display libraries.the use of xenopus laevis as a model for vertebrate developmental biology is limited by a lack of antibodies specific for embryonic antigens. this study evaluated the use of immune and non-immune phage display libraries for the isolation of single domain antibodies, or nanobodies, with specificities for xenopus embryonic antigens. the immune nanobody library was derived from peripheral blood lymphocyte rna obtained from a llama immunized with xenopus gastrula homogenates. screening this library ...201931048885
positively charged tags impede protein mobility in cells as quantified by 19f nmr.proteins are often tagged for visualization or delivery in the "sea" of other macromolecules in cells but how tags affect protein mobility remains poorly understood. here, we employ in-cell 19f nmr to quantify the mobility of proteins with charged tags in escherichia coli cells and xenopus laevis oocytes. we find that the transient charge-charge interactions between the tag and cellular components affect protein mobility. more specifically, positively charged tags impede protein mobility.201931042382
wolf-hirschhorn syndrome-associated genes are enriched in motile neural crest cells and affect craniofacial development in xenopus laevis.wolf-hirschhorn syndrome (whs) is a human developmental disorder arising from a hemizygous perturbation, typically a microdeletion, on the short arm of chromosome four. in addition to pronounced intellectual disability, seizures, and delayed growth, whs presents with a characteristic facial dysmorphism and varying prevalence of microcephaly, micrognathia, cartilage malformation in the ear and nose, and facial asymmetries. these affected craniofacial tissues all derive from a shared embryonic pre ...201931031646
methods for investigating trp channel gating.a complete characterization of temperature -and voltage-activated trp channel gating requires a precise determination of the absolute probability of opening in a wide range of voltages, temperatures, and agonist concentrations. we have achieved this in the case of the trpm8 channel expressed in xenopus laevis oocytes. measurements covered an extensive range of probabilities and unprecedented applied voltages up to 500 mv. in this chapter, we describe animal care protocols of patch-clamp pipette ...201931028680
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
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
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
altering the levels of nuclear import factors in early xenopus laevis embryos affects later development.more than just a container for dna, the nuclear envelope carries out a wide variety of critical and highly regulated cellular functions. one of these functions is nuclear import, and in this study we investigate how altering the levels of nuclear transport factors impacts developmental progression and organismal size. during early xenopus laevis embryogenesis, the timing of a key developmental event, the midblastula transition (mbt), is sensitive to nuclear import factor levels. how might alteri ...201931009515
urokinase-type plasminogen activator (upa) is not essential for epithelial sodium channel (enac)-mediated sodium retention in experimental nephrotic syndrome.in nephrotic syndrome, aberrantly filtered plasminogen (plg) is converted to active plasmin by tubular urokinase-type plasminogen activator (upa) and thought to lead to sodium retention by proteolytic activation of the epithelial sodium channel (enac). this concept predicts that upa is an important factor for sodium retention and that inhibition of upa might be protective in nephrotic syndrome.201931006168
cell type-specific transcriptome analysis unveils secreted signaling molecule genes expressed in apical epithelial cap during appendage regeneration.wound epidermis (we) and the apical epithelial cap (aec) are believed to trigger regeneration of amputated appendages such as limb and tail in amphibians by producing certain secreted signaling molecules. to date, however, only limited information about the molecular signatures of these epidermal structures is available. here we used a transgenic xenopus laevis line harboring the enhanced green fluorescent protein (egfp) gene under control of an es1 gene regulatory sequence to isolate we/aec cel ...201931713234
in vitro modeling of batrachochytrium dendrobatidis infection of the amphibian skin.the largest current disease-induced loss of vertebrate biodiversity is due to chytridiomycosis and despite the increasing understanding of the pathogenesis, knowledge unravelling the early host-pathogen interactions remains limited. batrachochytrium dendrobatidis (bd) zoospores attach to and invade the amphibian epidermis, with subsequent invasive growth in the host skin. availability of an in vitro assay would facilitate in depth study of this interaction while reducing the number of experiment ...201931725762
overexpression of ataap1 increased the uptake of an alanine-chlorantraniliprole conjugate in arabidopsis thaliana.transporters play an important role in the uptake and redistribution of agrochemicals to the site of insect feeding. the product of the arabidopsis thaliana gene ataap1 substantially contributes to inorganic nitrogen acquisition under ecologically relevant amino acid concentrations. here, the transporter ability of ataap1 to a chlorantraniliprole-alanine conjugate (cap-ala-1) was tested both in planta and in vitro. thirty-day-old and 15-day-old plants overexpressing ataap1 increased the uptake o ...201931741272
a prototype of the mammalian sulfotransferase 1 (sult1) family in xenopus laevis: molecular and enzymatic properties of xlsult1b.s.the cytosolic sulfotransferase 1 (sult1) proteins are a family of highly divergent proteins that show variable expansion in different species during vertebrate evolution. to clarify the evolutionary origin of the mammalian lineage of the sult1 family, we compiled xenopus laevis and x. tropicalis sult1 (xsult1) sequences from public databases. the xsult1 family was found to comprise at least six subfamilies, which corresponded in part to five mammalian sult1 subfamilies but only poorly to zebrafi ...201931748465
the chalcone lonchocarpin inhibits wnt/β-catenin signaling and suppresses colorectal cancer proliferation.the deregulation of the wnt/β-catenin signaling pathway is a central event in colorectal cancer progression, thus a promising target for drug development. many natural compounds, such as flavonoids, have been described as wnt/β-catenin inhibitors and consequently modulate important biological processes like inflammation, redox balance, cancer promotion and progress, as well as cancer cell death. in this context, we identified the chalcone lonchocarpin isolated from lonchocarpus sericeus as a wnt ...201931817828
optimized photo-stimulation of halorhodopsin for long-term neuronal inhibition.optogenetic silencing techniques have expanded the causal understanding of the functions of diverse neuronal cell types in both the healthy and diseased brain. a widely used inhibitory optogenetic actuator is enphr3.0, an improved version of the light-driven chloride pump halorhodopsin derived from natronomonas pharaonis. a major drawback of enphr3.0 is related to its pronounced inactivation on a time-scale of seconds, which renders it unsuited for applications that require long-lasting silencin ...201931775747
the tff peptides xp1 and xp4 appear in distinctive forms in the xenopus laevis gastric mucosa: indications for different protective functions.the gastric secretory trefoil factor family (tff) peptides xp1 and xp4 are the xenopus laevis orthologs of mammalian tff1 and tff2, respectively. the aim of this study was to analyze the molecular forms of xp1 and xp4 in the x. laevis gastric mucosa by fplc. xp1 mainly occurred in a monomeric low-molecular-mass form and only a minor subset is associated with the mucus fraction. the occurrence of monomeric xp1 is unexpected because of its odd number of cysteine residues. probably a conserved acid ...201931801293
mathematical model explaining the role of cdc6 in the diauxic growth of cdk1 activity during the m-phase of the cell cycle.in this paper we propose a role for the cdc 6 protein in the entry of cells into mitosis. this has not been considered in the literature so far. recent experiments suggest that cdc 6 , upon entry into mitosis, inhibits the appearance of active cdk 1 and cyclin b complexes. this paper proposes a mathematical model which incorporates the dynamics of kinase cdk 1 , its regulatory protein cyclin b, the regulatory phosphatase cdc 25 and the inhibitor cdc 6 known to be involved in the regulation of ac ...201931795221
expression and ion transport activity of rice oshkt1;1 variants.oshkt1;1 in rice, belongs to the high-affinity k+ transporter family, has been found to be involved in salt tolerance. oshkt1;1 in japonica rice (nipponbare) produces mrna variants, but their functions remain elusive. in salt tolerant rice, pokkali, eight oshkt1;1 variants (v1-v8) were identified in addition to the full-length oshkt1;1 (fl) cdna. absolute quantification by qpcr revealed that accumulation of oshkt1;1-fl mrna is minor in contrast to that of oshkt1;1-v1, -v2, -v4, and -v7 mrnas, al ...201931877741
a novel calcium-activated potassium channel controls membrane potential and intracellular ph in trypanosoma cruzi.trypanosoma cruzi develops in environments where nutrient availability, osmolarity, ionic concentrations, and ph undergo significant changes. the ability to adapt and respond to such conditions determines the survival and successful transmission of t. cruzi. ion channels play fundamental roles in controlling physiological parameters that ensure cell homeostasis by rapidly triggering compensatory mechanisms. combining molecular, cellular and electrophysiological approaches we have identified and ...201932010643
characterization of spinal cord damage based on automatic video analysis of froglet swimming.xenopus laevis frogs are a widely used organism to study aspects of modern biology ( harland and grainger, 2011). its central nervous system is particularly interesting, because in certain stages of metamorphosis the spinal cord can regenerate after injury and recover swimming. with this in mind, automatic gait analysis could help evaluate the regenerative performance by means of a method that automatically and quantitatively establishes the degree in froglets' limb movement. here, we present an ...201931852668
prominin-1 and photoreceptor cadherin localization in xenopus laevis: protein-protein relationships and function.retinal degenerative diseases are genetically diverse and rare inherited disorders that cause the death of rod and cone photoreceptors, resulting in progressive vision loss and blindness. this review will focus on two retinal degeneration-causing genes: prominin-1 (prom1) and photoreceptor cadherin (prcad). we will discuss protein localization, potential roles in photoreceptor outer segment disc morphogenesis, and areas for future investigation.201931884658
autophagy induction by hdac inhibitors is unlikely to be the mechanism of efficacy in prevention of retinal degeneration caused by p23h rhodopsin.we previously found that valproic acid (vpa) and other histone deacetylase inhibitors (hdacis) ameliorate retinal degeneration (rd) caused by p23h rhodopsin in xenopus laevis larvae and hypothesized that this may be due to enhancement of autophagy. here we use x. laevis expressing an autophagy marker to assess effects of hdacis on autophagy. we also assess the effects of non-hdaci activators and inducers of autophagy on rd caused by p23h rhodopsin.201931884645
the peptide transporter 1a of the zebrafish danio rerio, an emerging model in nutrigenomics and nutrition research: molecular characterization, functional properties, and expression analysis.peptide transporter 1 (pept1, alias slc15a1) mediates the uptake of dietary di/tripeptides in all vertebrates. however, in teleost fish, more than one pept1-type transporter might function, due to specific whole genome duplication event(s) that occurred during their evolution leading to a more complex paralogue gene repertoire than in higher vertebrates (tetrapods).201931890051
loc496300 is expressed in the endoderm of developing xenopus laevis embryos. 201932550462
using hdr and a template to introduce an in-frame ha tag on the 3' end of the xenopus laevis gata2.l open reading frame. 201932550411
environmental oxygen exposure allows for the evolution of interdigital cell death in limb patterning.amphibians form fingers without webbing by differential growth between digital and interdigital regions. amniotes, however, employ interdigital cell death (icd), an additional mechanism that contributes to a greater variation of limb shapes. here, we investigate the role of environmental oxygen in the evolution of icd in tetrapods. while cell death is restricted to the limb margin in amphibians with aquatic tadpoles, eleutherodactylus coqui, a frog with terrestrial-direct-developing eggs, has ce ...201931204171
transcriptome profiling reveals male- and female-specific gene expression pattern and novel gene candidates for the control of sex determination and gonad development in xenopus laevis.xenopus laevis is an amphibian (frog) species widely used in developmental biology and genetics. to unravel the molecular machinery regulating sex differentiation of xenopus gonads, we analyzed for the first time the transcriptome of developing amphibian gonads covering sex determination period. we applied microarray at four developmental stages: (i) nf50 (undifferentiated gonad during sex determination), (ii) nf53 (the onset of sexual differentiation of the gonads), (iii) nf56 (sexual different ...201930972573
expression of tcr genes in adult and larval xenopus laevis.in order to better understand the development and function of γδ t cells in xenopus frogs, it is necessary to determine where and when γδ t cells are found in xenopus tissues. this study examined the expression of tcr genes, focused primarily on tcr γ, in tissues of adult and larval xenopus laevis and provide new data about the expression pattern of these different tcr genes in this anuran amphibian. tcr gene expression was detected by rt-pcr in adult frog tissues including the thymus, spleen, s ...201930738793
conservation and divergence of protein pathways in the vertebrate heart.heart disease is the leading cause of death in the western world. attaining a mechanistic understanding of human heart development and homeostasis and the molecular basis of associated disease states relies on the use of animal models. here, we present the cardiac proteomes of 4 model vertebrates with dual circulatory systems: the pig (sus scrofa), the mouse (mus musculus), and 2 frogs (xenopus laevis and xenopus tropicalis). determination of which proteins and protein pathways are conserved and ...201931490923
discovery of the arp2 protein as a determining molecule in tumor cell death.cancer is a multifactorial disease that constitutes a serious public health problem worldwide. prostate cancer advanced stages are associated with the development of androgen-independent tumors and an apoptosis-resistant phenotype that progresses to metastasis. by studying androgen-independent lymphoid nodule carcinoma of the prostate (lncap) cells induced to apoptosis by serum elimination, we identified the activation of a non-selective cationic channel of 23ps conductance that promotes incomin ...201932091029
descubrimiento de la proteína reguladora de apoptosis 2 como determinante en la muerte de células tumorales.cancer is a multifactorial disease that constitutes a serious public health problem worldwide. prostate cancer advanced stages are associated with the development of androgen-independent tumors and an apoptosis-resistant phenotype that progresses to metastasis. by studying androgen-independent lymphoid nodule carcinoma of the prostate (lncap) cells induced to apoptosis by serum elimination, we identified the activation of a non-selective cationic channel of 23ps conductance that promotes incomin ...201931695224
a flipr assay for discovery of gabaa receptor modulators of natural origin.a fluorometric imaging plate reader (flipr) assay utilizing chinese hamster ovary (cho) cells stably transfected with gabaa receptors of α1β2γ2 subunit composition was evaluated and validated for rapid screening of plant extract libraries and efficient localization of active compounds in extracts. validation was performed with pure compounds and extracts known to contain allosteric gabaa receptor modulators. plants extracts that had been previously reported as active in an assay using xenopus la ...201931127604
lissamphibian limbs and the origins of tetrapod hox domains.the expression and function of hox genes have played a key role in the debate on the evolution of limbs from fins. as an early branching tetrapod lineage, lissamphibians may provide information on the origin of the limb's hox domains and particularly how the plesiomorphic tetrapod pattern compares to the hox pattern present in fish fins. here, we comparatively investigated the expression of hox genes in the developing limbs of axolotl and xenopus laevis as well as in the fins of the direct devel ...201931445923
broad applicability of a streamlined ethyl cinnamate-based clearing procedure.turbidity and opaqueness are inherent properties of tissues that limit the capacity to acquire microscopic images through large tissues. creating a uniform refractive index, known as tissue clearing, overcomes most of these issues. these methods have enabled researchers to image large and complex 3d structures with unprecedented depth and resolution. however, tissue clearing has been adopted to a limited extent due to a combination of cost, time, complexity of existing methods and potential nega ...201930665888
evaluating potential distribution of high-risk aquatic invasive species in the water garden and aquarium trade at a global scale based on current established populations.aquatic non-native invasive species are commonly traded in the worldwide water garden and aquarium markets, and some of these species pose major threats to the economy, the environment, and human health. understanding the potential suitable habitat for these species at a global scale and at regional scales can inform risk assessments and predict future potential establishment. typically, global habitat suitability models are fit for freshwater species with only climate variables, which provides ...201930428498
heterologous expression of aedes aegypti cation chloride cotransporter 2 (aeccc2) in xenopus laevis oocytes induces an enigmatic na⁺/li⁺ conductance.the yellow fever mosquito aedes aegypti possesses three genes encoding putative na⁺-coupled cation chloride cotransporters (cccs): aenkcc1, aeccc2, and aeccc3. to date, none of the aecccs have been functionally characterized. here we expressed aeccc2 heterologously in xenopus oocytes and measured the uptake of li⁺ (a tracer for na⁺) and rb⁺ (a tracer for k⁺). compared to control (h₂o-injected) oocytes, the aeccc2-expressing oocytes exhibited significantly greater uptake of li⁺, but not rb⁺. howe ...201930875796
the effects of insecticides on two splice variants of the glutamate-gated chloride channel receptor of the major malaria vector, anopheles gambiae.between half to 1 million people die annually from malaria. anopheles gambiae mosquitoes are major malaria vectors. unfortunately, resistance has emerged to the agents currently used to control a. gambiae, creating a demand for novel control measures. the pentameric glutamate-gated chloride channel (glucl) expressed in the muscle and nerve cells of these organisms are a potentially important biological target for malaria control. the pharmacological properties of anophiline glucl receptors are, ...201931479507
preventing ethanol-induced brain and eye morphology defects using optogenetics.background: embryonic exposure to the teratogen ethanol leads to dysmorphias, including eye and brain morphology defects associated with fetal alcohol spectrum disorder (fasd). exposure of xenopus laevis embryos to ethanol leads to similar developmental defects, including brain and eye dysmorphism, confirming our work and the work of others showing xenopus as a useful system for studies of the brain and eye birth defects associated with fasd. several targets of ethanol action have been hypothesi ...201932685918
myelopoiesis of the amphibian xenopus laevis is segregated to the bone marrow, away from their hematopoietic peripheral liver.across vertebrates, hematopoiesis takes place within designated tissues, wherein committed myeloid progenitors further differentiate toward cells with megakaryocyte/erythroid potential (mep) or those with granulocyte/macrophage potential (gmp). while the liver periphery (lp) of the xenopus laevis amphibian functions as a principal site of hematopoiesis and contains meps, cells with gmp potential are instead segregated to the bone marrow (bm) of this animal. presently, using gene expression and w ...201932038608
antiarrhythmic properties of ranolazine: inhibition of atrial fibrillation associated task-1 potassium channels.background: atrial fibrillation (af) is the most common sustained cardiac arrhythmia and one of the major causes of cardiovascular morbidity and mortality. despite good progress within the past years, safe and effective treatment of af remains an unmet clinical need. the anti-anginal agent ranolazine has been shown to exhibit antiarrhythmic properties via mainly late ina and ikr blockade. this results in prolongation of the atrial action potential duration (apd) and effective refractory period ( ...201932038227
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
endoplasmic reticulum network formation with xenopus egg extracts.the endoplasmic reticulum (er) consists of morphologically distinct domains, including a polygonal network of tubules that is connected by three-way junctions. this network is found in all eukaryotic cells. extracts from xenopus laevis eggs contain stockpiles of components that allow the assembly of an er network in vitro. here we provide protocols for assembly of er networks in extracts that are arrested at different stages of the cell cycle. unfertilized xenopus laevis eggs contain a cytostati ...201929475993
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
nucleotide receptor p2ry4 is required for head formation via induction and maintenance of head organizer in xenopus laevis.vertebrates have unique head structures that are mainly composed of the central nervous system, the neural crest, and placode cells. these head structures are brought about initially by the neural induction between the organizer and the prospective neuroectoderm at early gastrula stage. purinergic receptors are activated by nucleotides released from cells and influence intracellular signaling pathways, such as phospholipase c and adenylate cyclase signaling pathways. as p2y receptor is vertebrat ...201930069871
chromatin characterization in xenopus laevis cell-free egg extracts and embryos.xenopus laevis development is marked by accelerated cell division solely supported by the proteins maternally deposited in the egg. oocytes mature to eggs with concomitant transcriptional silencing. the unique maternal chromatin state contributing to this silencing and subsequent zygotic activation is likely established by histone posttranslational modifications and histone variants. therefore, tools for understanding the nature and function of maternal and embryonic histones are essential to de ...201929475998
the role of ambient temperature and body mass on body temperature, standard metabolic rate and evaporative water loss in southern african anurans of different habitat specialisation.temperature and water availability are two of the most important variables affecting all aspects of an anuran's key physiological processes such as body temperature (tb), evaporative water loss (ewl) and standard metabolic rate (smr). since anurans display pronounced sexual dimorphism, evidence suggests that these processes are further influenced by other factors such as vapour pressure deficit (vpd), sex and body mass (mb). however, a limited number of studies have tested the generality of thes ...201931660269
robustly cycling xenopus laevis cell-free extracts in teflon chambers.a central advantage of studying xenopus laevis is the manipulability of its cell-free extracts, which perform the cell cycle in vitro. however, these extracts are known to be experimentally temperamental and will often complete at most one or two cycles. over the course of developing systems for imaging cell cycle events in extracts in real time, we unexpectedly found that when standard xenopus extracts are placed in teflon tubes, they cycle extremely robustly; in one series of experiments, over ...201829475997
centromere and kinetochore assembly in xenopus laevis egg extract.during cell division, chromosomes must be equally segregated to daughter cells. centromeres, the primary interaction site between chromosomes and microtubules, mediate faithful chromosome segregation during mitosis. functional studies of centromere proteins in cells have proven difficult, as mutation or deletion of most centromeric proteins often results in cell lethality. in this protocol, sperm chromatin or reconstituted chromatin arrays, together with xenopus laevis egg extracts, are used to ...201829475995
micrornas associated with early neural crest development in xenopus laevis.the neural crest (nc) is a class of transitory stem cell-like cells unique to vertebrate embryos. nc cells arise within the dorsal neural tube where they undergo an epithelial to mesenchymal transition in order to migrate and differentiate throughout the developing embryo. the derivative cell types give rise to multiple tissues, including the craniofacial skeleton, peripheral nervous system and skin pigment cells. several well-studied gene regulatory networks underpin nc development, which when ...201829347911
[morphomechanical factors in gastrulation process and differentiation of embryonic tissue of xenopus laevis].effect of mechanical stretch on the differentiation of axial anlages and chordin gene expressionwas studied in sandwich explants prepared from embryonic tissues of xenopus laevis at the early gastrula stagein two variants: with dissected or intact dorso-medial region. in the first case, convergent cell movementswere suppressed and properly organized axial organs (notochord and somites) were almost completely absent.however, they developed if the explants of such type were artificially stretched ...201830272924
Refresh
firstprev
12345678910...
nextlast
Displaying items 501 - 600 of 17138