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grp94 regulates the recruitment of aneural achr clusters for the assembly of postsynaptic specializations by modulating adf/cofilin activity and turnover.temperature is a physiological factor that affects neuronal growth and synaptic homeostasis at the invertebrate neuromuscular junctions (nmjs); however, whether temperature stress could also regulate the structure and function of the vertebrate nmjs remains unclear. in this study, we use xenopus laevis primary cultures as a vertebrate model system for investigating the involvement of heat shock protein 90 (hsp90) family of stress proteins in nmj development. first, cold temperature treatment or ...202032747457
exploring the relationships between amphibian (xenopus laevis) myeloid cell subsets.the differentiation of distinct leukocyte subsets is governed by lineage-specific growth factors that elicit disparate expression of transcription factors and markers by the developing cell populations. for example, macrophages (mφs) and granulocytes (grns) arise from common granulocyte-macrophage progenitors in response to distinct myeloid growth factors. in turn, myelopoiesis of the xenopus laevis anuran amphibian appears to be unique to other studied vertebrates in several respects while the ...202032745480
analysis of pallial/cortical interneurons in key vertebrate models of testudines, anurans and polypteriform fishes.the organization of the pallial derivatives across vertebrates follows a comparable elementary arrangement, although not all of them possess a layered cortical structure as sophisticated as the cerebral cortex of mammals. however, its expansion along evolution has only been possible by the development and coevolution of the cellular networks formed by excitatory neurons and inhibitory interneurons. thus, the comparative analysis of interneuron types in vertebrate models of key evolutionary signi ...202032743670
rare heterozygous gdf6 variants in patients with renal anomalies.although over 50 genes are known to cause renal malformation if mutated, the underlying genetic basis, most easily identified in syndromic cases, remains unsolved in most patients. in search of novel causative genes, whole-exome sequencing in a patient with renal, i.e., crossed fused renal ectopia, and extrarenal, i.e., skeletal, eye, and ear, malformations yielded a rare heterozygous variant in the gdf6 gene encoding growth differentiation factor 6, a member of the bmp family of ligands. previo ...202032737436
new insights in the mode of action of (+)-erythravine and (+)-11α-hydroxy-erythravine alkaloids.erythrinian alkaloids ((+)-erythravine and (+)-11-α-hydroxy-erythravine) have been pointed as the main responsible agents for the anticonvulsant and anxiolytic properties of erythrina mulungu mart ex benth. the present work provides a new set of information about the mode of action of these alkaloids by the use of a complementary approach of neurochemical and electrophysiological assays. we propose here that the antiepileptic and anxiolytic properties exhibited by both alkaloids appear not to be ...202032735983
zinc protection of fertilized eggs is an ancient feature of sexual reproduction in animals.one of the earliest and most prevalent barriers to successful reproduction is polyspermy, or fertilization of an egg by multiple sperm. to prevent these supernumerary fertilizations, eggs have evolved multiple mechanisms. it has recently been proposed that zinc released by mammalian eggs at fertilization may block additional sperm from entering. here, we demonstrate that eggs from amphibia and teleost fish also release zinc. using xenopus laevis as a model, we document that zinc reversibly block ...202032735558
polyploidization and pseudogenization in allotetraploid frog xenopus laevis promote the evolution of aquaporin family in higher vertebrates.aquaporins (aqps), as members of the major intrinsic protein (mip) superfamily, facilitated the permeation of water and other solutes and are involved in multiple biological processes. aqp family exists in almost all living organisms and is highly diversified in vertebrates in both classification and function due to genome wide duplication. while some aqp orthologs have been lost in higher vertebrates through evolution.202032727380
postsynaptic and presynaptic nmdars have distinct roles in visual circuit development.to study contributions of n-methyl-d-aspartate receptors (nmdars) in presynaptic and postsynaptic neurons of the developing visual system, we microinject antisense morpholino oligonucleotide (mo) against glun1 into one cell of two-cell-stage xenopus laevis embryos. the resulting bilateral segregation of mo induces postsynaptic nmdar (postnmdar) knockdown in tectal neurons on one side and presynaptic nmdar (prenmdar) knockdown in ganglion cells projecting to the other side. postnmdar knockdown re ...202032726620
intracellular motor-driven transport of rodlike smooth organelles along microtubules.molecular motors are fascinating proteins that use the energy of atp hydrolysis to drive vesicles and organelles along cytoskeleton filaments toward their final destination within the cell. several copies of these proteins bind to the cargo and take turns transporting the cargo attaching to and detaching from the track stochastically. despite the relevance of molecular motors to cell physiology, key aspects of their collective functioning are still unknown. in this work we propose a one-dimensio ...202032688554
mucociliary epithelial organoids from xenopus embryonic cells: generation, culture and high-resolution live imaging.mucociliary epithelium provides the first line of defense by removing foreign particles through the action of mucus production and cilia-mediated clearance. many clinically relevant defects in the mucociliary epithelium are inferred as they occur deep within the body. here, we introduce a tractable 3d model for mucociliary epithelium generated from multipotent progenitors that were microsurgically isolated from xenopus laevis embryos. the mucociliary epithelial organoids are covered with newly g ...202032804169
redox priming promotes aurora a activation during mitosis.cell cycle-dependent redox changes can mediate transient covalent modifications of cysteine thiols to modulate the activities of regulatory kinases and phosphatases. our previously reported finding that protein cysteine oxidation is increased during mitosis relative to other cell cycle phases suggests that redox modifications could play prominent roles in regulating mitotic processes. the aurora family of kinases and their downstream targets are key components of the cellular machinery that ensu ...202032694171
conservation of glomerular organization in the main olfactory bulb of anuran larvae.the glomerular array in the olfactory bulb of many vertebrates is segregated into molecularly and anatomically distinct clusters linked to different olfactory functions. in anurans, glomerular clustering is so far only described in xenopus laevis. we traced olfactory projections to the bulb in tadpoles belonging to six distantly related anuran species in four families (pipidae, hylidae, bufonidae, dendrobatidae) and found that glomerular clustering is remarkably conserved. the general bauplan co ...202032792916
exposure impacts of environmentally relevant concentrations of a glufosinate ammonium herbicide formulation on larval development and thyroid histology of xenopus laevis.thyroid hormones play critical roles in body growth and development as well as reproduction. they also influence the activities of a wider variety of tissues and biological functions, such as osmoregulation, metabolism, and especially metamorphosis in organisms, such as frogs. these complex activities of thyroid hormones are prone to disruption by agricultural pesticides, often leading to modulation of growth and the reproductive system in particular. these substances include glufosinate ammoniu ...202032948887
an integrated approach to assess the sublethal effects of colloidal gold nanorods in tadpoles of xenopus laevis.gold nanorods (aunr) have been explored for many applications, including innovative nanomedicines, which also might contribute to its increase in the environment, namely due to inadequate disposable of wastes into aquatic environments. early-life stages of amphibians are usually aquatic and sensitive to chemical contamination. accordingly, this study aimed to determine the sublethal effects of ctab functionalized aunr on xenopus laevis tadpoles. as such, tadpoles were exposed to serial concentra ...202032947686
antimicrobial peptide induced-stress renders staphylococcus aureus susceptible to toxic nucleoside analogs.cationic antimicrobial peptides (amps) are active immune effectors of multicellular organisms and are also considered as new antimicrobial drug candidates. one of the problems encountered when developing amps as drugs is the difficulty of reaching sufficient killing concentrations under physiological conditions. here, using pexiganan, a cationic peptide derived from a host defense peptide of the african clawed frog and the first amp developed into an antibacterial drug, we studied whether sub-le ...202033133056
embryonic epidermal lectins in three amphibian species, rana ornativentris, bufo japonicus formosus, and cynops pyrrhogaster.intelectins (itlns) are secretory lectins found in several chordate species that recognize carbohydrates on the bacterial cell surface depending on ca2+ . in newly hatched larvae of rana ornativentris (r. orn), bufo japonicus formosus (b. jpn), and cynops pyrrhogaster (c. pyr), an anti-itln monoclonal antibody (mab) labeled a subset of epidermal cells in whole-mount immunocytochemical assays. in western blot analyses, the mab identified protein bands at approximately 33-37 kda in the larval extr ...202032729712
mechanisms activating latent functions of pip aquaporin water channels via the interaction between pip1 and pip2 proteins.plant plasma-membrane type pip aquaporins are classified into two groups, pip1s and pip2s. in this study, we focused on hvpip1; 2, a pip1 in barley (hordeum vulgare), to dissect the molecular mechanisms that evoke hvpip1-mediated water transport. no hvpip1; 2 protein was localized to the plasma membrane when expressed alone in xenopus laevis oocytes. in contrast, a chimeric hvpip1; 2 protein (hvpip1; 2_24nc), in which the n- and c-terminal regions were replaced with the corresponding regions fro ...202033169164
synthesis of glun2a-selective nmda receptor antagonists with an electron-rich aromatic b-ring.glutamatergic n-methyl-d-aspartate (nmda) receptors are heterotetrameric ion channels that can be comprised of different subunits. glun2a subunit-containing nmda receptors are associated with diseases like anxiety, depression, and schizophrenia. however, the exact contribution of these nmda receptor subtypes is still unclear. to understand better the role of the glun2a-containing receptors, novel ligands were designed. in co-crystallization with the isolated binding site, tcn-201 (1) and analogs ...202033162207
development of antimicrobial peptides from amphibians.since the discovery of magainins from the skin secretions of the african toad xenopus laevis by michael zasloff in 1987, an increasing number of antimicrobial peptides (amps) has been identified in different anuran species and studied in detail [...].202033158031
epigenetic regulation of replication origin assembly: a role for histone h1 and chromatin remodeling factors.during early embryonic development in several metazoans, accurate dna replication is ensured by high number of replication origins. this guarantees rapid genome duplication coordinated with fast cell divisions. in xenopus laevis embryos this program switches to one with a lower number of origins at a developmental stage known as mid-blastula transition (mbt) when cell cycle length increases and gene transcription starts. consistent with this regulation, somatic nuclei replicate poorly when trans ...202033165968
nicotinic acetylcholine receptors in the synganglion of the tick ixodes ricinus: functional characterization using membrane microtransplantation.nicotinic acetylcholine receptors are an important class of excitatory receptors in the central nervous system of arthropods. in the ticks ixodes ricinus, the functional and pharmacological properties of nicotinic receptors located in their neurons are still unknown. the objective of this study was to characterize the pharmacological properties of tick nicotinic receptors using membrane microtransplantation in xenopus laevis oocytes and two-electrodes voltage clamp method. the membranes microtra ...202033120248
aquaporin expression in the alimentary canal of the honey bee apis mellifera l. (hymenoptera: apidae) and functional characterization of am_eglp 1.aquaporins (aqp) are a family of plasma membrane proteins responsible for water transport through cell membranes. they are differentially expressed in different parts of the alimentary canal of insects where they regulate water transport. these proteins have been studied in detail in some insects, but few data are available for aquaporins of the honey bee, apis mellifera. we used quantitative pcr to study the expression of six putative aquaporin genes in forager honey bees. we found differential ...202032956406
observation of nucleic acids inside living human cells by in-cell nmr spectroscopy.the intracellular environment is highly crowded with biomacromolecules such as proteins and nucleic acids. under such conditions, the structural and biophysical features of nucleic acids have been thought to be different from those in vitro. to obtain high-resolution structural information on nucleic acids in living cells, the in-cell nmr method is a unique tool. following the first in-cell nmr measurement of nucleic acids in 2009, several interesting insights were obtained using xenopus laevis ...202033110737
high affinity na+ transport by wheat hkt1;5 is blocked by k.the wheat sodium transporters tmhkt1;5-a and tahkt1;5-d are encoded by genes underlying the major shoot na+ exclusion loci nax2 and kna1 from triticum monococcum (tm) and triticum aestivum (ta), respectively. in contrast to hkt2 transporters that have been shown to exhibit high affinity k+-dependent na+ transport, hkt1 proteins have, with one exception, only been shown to catalyze low affinity na+ transport and no k+ transport. here, using heterologous expression in xenopus laevis oocytes we unc ...202033103046
x-box-binding protein 1 is required for pancreatic development in xenopus laevis.x-box-binding protein 1 (xbp1) is a protein containing the basic leucine zipper structure. it belongs to the camp-response element binding protein (creb)/activating transcription factor transcription factor family. as the main transcription factor, spliced xbp1 (xbp1s) participates in many physiological and pathological processes and plays an important role in embryonic development. previous studies showed that xbp1-knockout mice died because of pancreatic exocrine function deficiency, indicatin ...202033098302
sclerostin inhibits wnt signaling through tandem interaction with two lrp6 ectodomains.low-density lipoprotein receptor-related protein 6 (lrp6) is a coreceptor of the β-catenin-dependent wnt signaling pathway. the lrp6 ectodomain binds wnt proteins, as well as wnt inhibitors such as sclerostin (sost), which negatively regulates wnt signaling in osteocytes. although lrp6 ectodomain 1 (e1) is known to interact with sost, several unresolved questions remain, such as the reason why sost binds to lrp6 e1e2 with higher affinity than to the e1 domain alone. here, we present the crystal ...202033097721
rad21 is involved in corneal stroma development by regulating neural crest migration.previously, we identified rad21r450c from a peripheral sclerocornea pedigree. injection of this rad21 variant mrna into xenopus laevis embryos disrupted the organization of corneal stroma fibrils. to understand the mechanisms of rad21-mediated corneal stroma defects, gene expression and chromosome conformation analysis were performed using cells from family members affected by peripheral sclerocornea. both gene expression and chromosome conformation of cell adhesion genes were affected in cells ...202033096935
phosphoproteomic analysis of xenopus laevis reveals expression and phosphorylation of hypoxia-inducible pfkfb3 during dehydration.xenopus laevis tolerate dehydration when their environments evaporate during summer months. protein phosphorylation has previously shown to regulate important adaptations in x. laevis, including the transition to anaerobic metabolism. we therefore performed phosphoproteomic analysis of x. laevis to further elucidate the cellular and metabolic responses to dehydration. phosphoproteins were enriched in cellular functions and pathways related to glycolysis/gluconeogenesis, the tca cycle, and protei ...202033083755
derivation of proliferative islet1-positive cells during metamorphosis and wound response in xenopus.in mammalian hearts, cardiomyocytes retain a transient capacity to proliferate and regenerate following injury before birth, whereas they lose proliferative capacity immediately after birth. it has also been known that cardiac progenitor cells including islet1-positive cells do not contribute to the cardiac repair and regeneration in mammals. in contrast, hearts of zebrafish, amphibians and reptiles maintain a regenerative ability throughout life. here, we analyzed proliferative capacity of card ...202033070205
non-junctional role of cadherin3 in cell migration and contact inhibition of locomotion via domain-dependent, opposing regulation of rac1.classical cadherins are well-known adhesion molecules responsible for physically connecting neighboring cells and signaling this cell-cell contact. recent studies have suggested novel signaling roles for "non-junctional" cadherins (njcads); however, the function of cadherin signaling independent of cell-cell contacts remains unknown. in this study, mesendodermal cells and tissues from gastrula stage xenopus laevis embryos demonstrate that deletion of extracellular domains of cadherin3 (cdh3; for ...202033060598
scorpion toxin meunatxα-1 sensitizes primary nociceptors by selective modulation of voltage-gated sodium channels.venoms are a rich source of highly specific toxins, which allow the identification of novel therapeutic targets. we have now applied high content screening (hcs) microscopy to identify toxins that modulate pain sensitization signaling in primary sensory neurons of rat and elucidated the underlying mechanism. a set of venoms and fractions thereof were analyzed for their ability to activate type ii protein kinase a (pka-ii) and extracellular signal-regulated kinases (erk1/2). we identified meunatx ...202033051988
glutamate, d-(-)-2-amino-5-phosphonopentanoic acid, and n-methyl-d-aspartate do not directly modulate glycine receptors.replication studies play an essential role in corroborating research findings and ensuring that subsequent experimental works are interpreted correctly. a previously published paper indicated that the neurotransmitter glutamate, along with the compounds n-methyl-d-aspartate (nmda) and d-(-)-2-amino-5-phosphonopentanoic acid (ap5), acts as positive allosteric modulators of inhibitory glycine receptors. the paper further suggested that this form of modulation would play a role in setting the spina ...202033051383
microtubule-dependent pushing forces contribute to long-distance aster movement and centration in xenopus laevis egg extracts.during interphase of the eukaryotic cell cycle, the microtubule (mt) cytoskeleton serves as both a supportive scaffold for organelles and an arborized system of tracks for intracellular transport. at the onset of mitosis, the position of the astral mt network, specifically its center, determines the eventual location of the spindle apparatus and ultimately the cytokinetic furrow. positioning of the mt aster often results in its movement to the center of a cell, even in large blastomeres hundreds ...202033026931
cross-talk between p2x and nmda receptors.purinergic p2x receptors (p2x) are atp-gated ion channels widely expressed in the cns. while the direct contribution of p2x to synaptic transmission is uncertain, p2x reportedly affect n-methyl-d-aspartate receptor (nmdar) activity, which has given rise to competing theories on the role of p2x in the modulation of synapses. however, p2x have also been shown to participate in receptor cross-talk: an interaction where one receptor (e.g., p2x2) directly influences the activity of another (e.g., nic ...202033003406
dna content contributes to nuclear size control in xenopus laevis.cells adapt to drastic changes in genome quantity during evolution and cell division by adjusting the nuclear size to exert genomic functions. however, the mechanism by which dna content within the nucleus contributes to controlling the nuclear size remains unclear. here, we experimentally evaluated the effects of dna content by utilizing cell-free xenopus egg extracts and imaging of in vivo embryos. upon manipulation of dna content while maintaining cytoplasmic effects constant, both plateau si ...202032997613
torc1 selectively regulates synaptic maturation and input convergence in the developing visual system.newly synthesized proteins support the development of functional neural circuits and previous work has suggested that dysregulated translation mediates certain forms of autism spectrum disorder (asd). here, we investigated the role of target of rapamycin complex 1 (torc1) in synaptic and dendritic development in vivo in the retinotectal system of xenopus laevis tadpoles. we found that torc1 signaling regulates dendritic growth and branching and that acute over-activation of torc1 by rheb overexp ...202032996262
a survey of barley pip aquaporin ionic conductance reveals ca2+-sensitive hvpip2;8 na+ and k+ conductance.some plasma membrane intrinsic protein (pip) aquaporins can facilitate ion transport. here we report that one of the 12 barley pips (pip1 and pip2) tested, hvpip2;8, facilitated cation transport when expressed in xenopus laevis oocytes. hvpip2;8-associated ion currents were detected with na+ and k+, but not cs+, rb+, or li+, and was inhibited by ba2+, ca2+, and cd2+ and to a lesser extent mg2+, which also interacted with ca2+. currents were reduced in the presence of k+, cs+, rb+, or li+ relativ ...202032992595
endoparasites infecting exotic captive amphibian pet and zoo animals (anura, caudata) in germany.alongside exotic reptiles, amphibians, such as toads, frogs, salamanders, and newts, are nowadays considered popular pets worldwide. as reported for other exotic pet animals, amphibians are known to harbor numerous gastrointestinal parasites. nonetheless, very little data are available on captive amphibian parasitic diseases. in this study, we applied direct saline fecal smears (dsfs) to examine in total 161 stool samples from 41 different amphibian species belonging to the orders anura and caud ...202032960371
inferring a complete genotype-phenotype map from a small number of measured phenotypes.understanding evolution requires detailed knowledge of genotype-phenotype maps; however, it can be a herculean task to measure every phenotype in a combinatorial map. we have developed a computational strategy to predict the missing phenotypes from an incomplete, combinatorial genotype-phenotype map. as a test case, we used an incomplete genotype-phenotype dataset previously generated for the malaria parasite's 'chloroquine resistance transporter' (pfcrt). wild-type pfcrt (pfcrt3d7) lacks signif ...202032991585
the mechanism of nmda receptor hyperexcitation in high pressure helium and hyperbaric oxygen.professional divers exposed to pressures greater than 1.1 mpa may suffer from the high pressure neurological syndrome (hpns). divers who use closed-circuit breathing apparatus face the risk of cns hyperbaric oxygen toxicity (hbotox). both syndromes are characterized by reversible cns hyperexcitability, accompanied by cognitive and motor deficits. previous studies have demonstrated that the hyperexcitability of hpns is induced mainly by nmda receptors (nmdars). in our recent studies, we demonstra ...202032982789
in-cell nmr spectroscopy of functional riboswitch aptamers in eukaryotic cells.we report here the in-cell nmr-spectroscopic observation of the binding of the cognate ligand 2'-deoxyguanosine to the aptamer domain of the bacterial 2'-deoxyguanosine-sensing riboswitch in eukaryotic cells, namely xenopus laevis oocytes and in human hela cells. the riboswitch is sufficiently stable in both cell types to allow for detection of binding of the ligand to the riboswitch. most importantly, we show that the binding mode established by in vitro characterization of this prokaryotic rib ...202032975353
amiodarone bioconcentration and suppression of metamorphosis in xenopus.trace concentrations of a number of pharmaceutically active compounds have been detected in the aquatic environment in many countries, where they are thought to have the potential to exert adverse effects on non-target organisms. amiodarone (amd) is one such high-risk compound commonly used in general hospitals. amd is known to alter normal thyroid hormone (th) function, although little information is available regarding the specific mechanism by which this disruption occurs. anuran tadpole meta ...202032956954
design, synthesis, and in vitro evaluation of p2x7 antagonists.the p2x7 receptor is a promising target for the treatment of various diseases due to its significant role in inflammation and immune cell signaling. this work describes the design, synthesis, and in vitro evaluation of a series of novel derivatives bearing diverse scaffolds as potent p2x7 antagonists. our approach was based on structural modifications of reported (adamantan-1-yl)methylbenzamides able to inhibit the receptor activation. the adamantane moieties and the amide bond were replaced, an ...202032964578
whole-brain calcium imaging in larval xenopus.sensory systems detect environmental stimuli and transform them into electrical activity patterns interpretable by the central nervous system. en route to higher brain centers, the initial sensory input is successively transformed by interposed secondary processing centers. mapping the neuronal activity patterns at all of those stages is essential to understand sensory information processing. larval xenopus laevis is very well-suited for whole-brain imaging of neuronal activity. this is mainly d ...202033037078
elucidating the framework for specification and determination of the embryonic retina.how cell determination is regulated remains a major unsolved problem in developmental biology. the early embryonic rudiments of many tissues and organs are difficult or impossible to identify, isolate and study at the time when determination occurs. we have examined the commitment process leading to retina formation in xenopus laevis, where presumptive eye tissue can be identified and studied to assay its biological properties during the events leading up to determination. we find that for the r ...202033031807
do muscle contractile properties drive differences in locomotor performance in invasive populations of xenopus laevis in france?jumping and swimming are key locomotor traits in frogs intimately linked to survival and dispersal. french populations of the frog xenopus laevis from the invasion front are known to possess greater terrestrial locomotor endurance. here, we tested whether individuals from the invasion front show differences in their muscle physiology that may underlie the observed whole-organism performance differences. we measured muscle contractile properties of the isolated gastrocnemius muscle in vitro, incl ...202032955613
effect of 158 herbal remedies on human trpv1 and the two-pore domain potassium channels kcnk2, 3 and 9.herbal medicines are used to treat a broad number of maladies. however, the pharmacological profile of most remedies is poorly understood. we investigated the effect of herbal remedies from kampo, traditional chinese medicine (tcm) and other phytotherapies on human two-pore domain potassium channels (kcnk channels; trek-1, task-1 and task-3) as well as the human trpv1 channel. kcnk channels are responsible for the background potassium current of excitable cells, thus essential for the maintenanc ...202032953560
α-conotoxin as potential to α7-nachr recombinant expressed in escherichia coli.α7 nicotinic acetylcholine receptors (nachr) is an important nicotinic acetylcholine receptors subtype and closely associated with cognitive disorders, such as alzheimer's and schizophrenia disease. the mutant arib (v11l, v16a) of α-conotoxin arib with 17-amino acid residues specifically targets α7 nachr with no obvious effect on other nachr subtypes. in the study, the synthetic gene encoding mature peptide of arib and mutant arib (v11l, v16a) carried a fusion protein trx and 6 × his-tag was sep ...202032806654
compaction of rna duplexes in the cell.the structure and flexibility of rna depends sensitively on the microenvironment. using pulsed electron-electron double-resonance (peldor)/double electron-electron resonance (deer) spectroscopy combined with advanced labeling techniques, we show that the structure of double-stranded rna (dsrna) changes upon internalization into xenopus laevis oocytes. compared to dilute solution, the dsrna a-helix is more compact in cells. we recapitulate this compaction in a densely crowded protein solution. at ...202032804430
establishing embryonic territories in the context of wnt signaling.this review highlights the work that my research group has been developing, together with international collaborators, during the last decade. since we were able to establish xenopus laevis experimental model in brazil we have been focused on understanding early embryonic patterns regarding neural induction and axes establishment. in this context, wnt pathway appears as a major player and has been much explored by us and other research groups. here we chose to review three published works that w ...202032930371
a collision coupling model governs the activation of neuronal girk1/2 channels by muscarinic-2 receptors.the g protein-activated inwardly rectifying k+-channel (girk) modulates heart rate and neuronal excitability. following g-protein coupled receptor (gpcr)-mediated activation of heterotrimeric g proteins (gαβγ), opening of the channel is obtained by direct binding of gβγ subunits. interestingly, girks are solely activated by gβγ subunits released from gαi/o-coupled gpcrs, despite the fact that all receptor types, for instance gαq-coupled, are also able to provide gβγ subunits. it is proposed that ...202032903404
experiences with the marsupial frogs: reminiscences of a developmental biologist.this article provides a brief account of the career of eugenia m. del pino. casual events and serendipity played important roles in modeling her career as developmental biologist. in collaboration with colleagues and students, she analyzed the biology and development of the marsupial frog gastrotheca riobambae (family: hemiphractidae) in comparison with xenopus laevis and tropical frogs. the emphasis was placed on oogenesis and the early stages of development. topics include the mono- and multi- ...202032813268
design, synthesis, and electrophysiological evaluation of ns6740 derivatives: exploration of the structure-activity relationship for alpha7 nicotinic acetylcholine receptor silent activation.the α7 nicotinic acetylcholine receptor (nachr) silent agonists, able to induce receptor desensitization and promote the α7 metabotropic function, are emerging as new promising therapeutic anti-inflammatory agents. herein, we report the structure-activity relationship investigation of the archetypal silent agonist ns6740 (1,4-diazabicyclo[3.2.2]nonan-4-yl(5-(3-(trifluoromethyl)-phenyl)-furan-2-yl)methanone) (1) to elucidate the ligand-receptor interactions responsible for the α7 silent activatio ...202032810771
diversity of parasites from xenopus laevis (amphibia: pipidae) and their seasonal rate of infection in selected habitats in the limpopo province, south africa.this study determined the diversity and seasonality of parasites species of the african clawed frog, xenopus laevis (daudin, 1802), from three localities, namely modjadjikloof, mokopane and university of limpopo, limpopo province, south africa. a total of seven parasite species were collected and identified. they included two nematodes, camallanus kaapstaadi southwell & kirshner, 1937 and batrachocamallanus slomei (southwell & kirshner, 1937), a monogenean, protopolystoma xenopodis (price, 1943) ...202032855613
blood-brain barrier protein claudin-5 expressed in paired xenopus laevis oocytes mediates cell-cell interaction.claudin-5 determines the sealing properties of blood-brain barrier tight junctions and its function is impaired in neurodegenerative and neuroinflammatory disorders. focusing on the contribution of claudin-5 to the trans-interaction within the tight junction seal, we used xenopus laevis oocytes as an expression system. cells were clustered and challenged in a novel approach for the analysis of claudin interaction. we evaluated the strengthening effect of claudin-5 to cell-cell-connection in comp ...202032848831
a simple and efficient method for visualizing individual cells in vivo by cre-mediated single-cell labeling by electroporation (cremscle).efficient methods for visualizing cell morphology in the intact animal are of great benefit to the study of structural development in the nervous system. quantitative analysis of the complex arborization patterns of brain cells informs cell-type classification, dissection of neuronal circuit wiring, and the elucidation of growth and plasticity mechanisms. time-lapse single-cell morphological analysis requires labeling and imaging of single cells in situ without contamination from the ramified pr ...202032848634
na+ transporter svhkt1;1 from a halophytic turf grass is specifically upregulated by high na+ concentration and regulates shoot na+ concentration.we characterized an na+ transporter svhkt1;1 from a halophytic turf grass, sporobolus virginicus. svhkt1;1 mediated inward and outward na+ transport in xenopus laevis oocytes and did not complement k+ transporter-defective mutant yeast. svhkt1;1 did not complement athkt1;1 mutant arabidopsis, suggesting its distinguishable function from other typical hkt1 transporters. the transcript was abundant in the shoots compared with the roots in s. virginicus and was upregulated by severe salt stress (50 ...202032847126
preliminary indications that recombinant human il-16 attracts and stimulates lymphocytes of the amphibian, xenopus laevis implying an ancestral role for cd4 as a cytokine receptor.the d1 domain of the cd4 co-receptor interacts with mhc class ii during helper cd4+ th-cell activation and effector function in all gnathostomes but the sequence and structure of this region are not well conserved through phylogeny. conversely, the proximal d4 domain of cd4 is the binding site of the cytokine il-16 and is highly conserved, allowing for promiscuous binding of il-16 to cd4 between disparate gnathostomes. we report here that recombinant human il-16 (rhil-16) bound to xenopus lympho ...202032836028
dynamic expression of mmp28 during cranial morphogenesis.matrix metalloproteinases (mmps) are a large family of proteases comprising 24 members in vertebrates. they are well known for their extracellular matrix remodelling activity. mmp28 is the latest member of the family to be discovered. it is a secreted mmp involved in wound healing, immune system maturation, cell survival and migration. mmp28 is also expressed during embryogenesis in human and mouse. here, we describe the detailed expression profile of mmp28 in xenopus laevis embryos. we show tha ...202032829678
effect of obps on the response of olfactory receptors.the technique of two-electrode voltage-clamp (tevc) recording from the heterologous expression system of olfactory receptors (ors) in xenopus laevis oocytes has been widely used to deorphanize insect ors, that is to identify specific ligands for each of them. however, there is a controversial issue on whether ors are activated by the odorant/obp complex or the odorant alone. the mechanism of interaction among odorants, odorant-binding proteins (obps) and ors remains largely unknown, due to the l ...202032828257
new insights into hcptr2a and hcptr2b, two high-affinity peptide transporters from the ectomycorrhizal model fungus hebeloma cylindrosporum.while plants mainly rely on the use of inorganic nitrogen sources like ammonium and nitrate, soil-borne microorganisms like the ectomycorrhizal fungus hebeloma cylindrosporum can also take up soil organic n in the form of amino acids and peptides that they use as nitrogen and carbon sources. following the previous identification and functional expression in yeast of two ptr-like peptide transporters, the present study details the functions and substrates of hcptr2a and hcptr2b by analysing their ...202032820366
identification of the essential extracellular aspartic acids conserved in human monocarboxylate transporters 1, 2, and 4.human monocarboxylate transporters (hmcts) 1-4 transport monocarboxylates, such as l-lactate and pyruvate, as well as h+ across the plasma membrane. hmct1, 2, and 4 play important roles in energy balance, ph homeostasis. however, the molecular mechanism of these transporters, especially their ph dependency, remains unknown. the aim of this study was to identify the residues involved in the ph dependence of hmct1, 2, and 4. firstly, we focused on the effects of extracellular acids of hmct1. l-lac ...202032819565
a non-canonical role for the dna glycosylase neil3 in suppressing ape1 endonuclease-mediated ssdna damage.the dna glycosylase neil3 has been implicated in dna repair pathways including the base excision repair and the interstrand cross-link repair pathways via its dna glycosylase and/or ap lyase activity, which are considered canonical roles of neil3 in genome integrity. compared with the other dna glycosylases neil1 and neil2, xenopus laevis neil3 c terminus has two highly conserved zinc finger motifs containing grxf residues (designated as zf-grf). it has been demonstrated that the minor ap endonu ...202032817342
tetrapeptide ac-haee-nh2 protects α4β2 nachr from inhibition by aβ.the cholinergic deficit in alzheimer's disease (ad) may arise from selective loss of cholinergic neurons caused by the binding of aβ peptide to nicotinic acetylcholine receptors (nachrs). thus, compounds preventing such an interaction are needed to address the cholinergic dysfunction. recent findings suggest that the 11evhh14 site in aβ peptide mediates its interaction with α4β2 nachr. this site contains several charged amino acid residues, hence we hypothesized that the formation of aβ-α4β2 nac ...202032872553
acute consequences of a unilateral viiith nerve transection on vestibulo-ocular and optokinetic reflexes in xenopus laevis tadpoles.loss of peripheral vestibular function provokes severe impairments of gaze and posture stabilization in humans and animals. however, relatively little is known about the extent of the instantaneous deficits. this is mostly due to the fact that in humans a spontaneous loss often goes unnoticed initially and targeted lesions in animals are performed under deep anesthesia, which prevents immediate evaluation of behavioral deficits. here, we use isolated preparations of xenopus laevis tadpoles with ...202032915311
uncoupling sodium channel dimers restores the phenotype of a pain-linked nav 1.7 channel mutation.the voltage-gated sodium channel nav 1.7 is essential for adequate perception of painful stimuli. mutations in the encoding gene, scn9a, cause various pain syndromes in humans. the hnav 1.7/a1632e channel mutant causes symptoms of erythromelalgia and paroxysmal extreme pain disorder (pepd), and its main gating change is a strongly enhanced persistent current. on the basis of recently published 3d structures of voltage-gated sodium channels, we investigated how the inactivation particle binds to ...202032663327
trpm6 and trpm7: novel players in cell intercalation during vertebrate embryonic development.a common theme in organogenesis is how the final structure of organs emerge from epithelial tube structures, with the formation of the neural tube being one of the best examples. two types of cell movements co-occur during neural tube closure involving the migration of cells toward the midline of the embryo (mediolateral intercalation or convergent extension) as well as the deep movement of cells from inside the embryo to the outside of the lateral side of the neural plate (radial intercalation) ...202032315468
effects of bisphenol a and its alternative bisphenol f on notch signaling and intestinal development: a novel signaling by which bisphenols disrupt vertebrate development.we previously found bisphenol a (bpa) alternative, bisphenol f (bpf) upregulated notch-related gene expression in intestines of the african clawed frog xenopus laevis, suggesting an agonistic action on notch signaling, a crucial signaling in multiple biological processes during development. here, we aimed to confirm the actions of bpa and bpf on notch signaling and to reveal their effects on intestinal development. using x. laevis, an excellent model for developmental biology, we found that 10-1 ...202032311622
modeling bainbridge-ropers syndrome in xenopus laevis embryos.the additional sex combs-like (asxl1-3) genes are linked to human neurodevelopmental disorders. the de novo truncating variants in asxl1-3 proteins serve as the genetic basis for severe neurodevelopmental diseases such as bohring-opitz, shashi-pena, and bainbridge-ropers syndromes, respectively. the phenotypes of these syndromes are similar but not identical, and include dramatic craniofacial defects, microcephaly, developmental delay, and severe intellectual disability, with a loss of speech an ...202032132929
evaluation of the effects of low concentrations of bisphenol af on gonadal development using the xenopus laevis model: a finding of testicular differentiation inhibition coupled with feminization.developmental exposures to estrogenic chemicals possibly cause structural and functional abnormalities of reproductive organs in vertebrates. bisphenol af (bpaf), a bisphenol a (bpa) analogue, has been shown to have higher estrogenic activity than bpa, but little is known about the effects of bpaf on gonadal development, particularly gonadal differentiation. we aimed to determine whether low concentrations of bpaf could disrupt gonadal differentiation and subsequent development using xenopus lae ...202031991354
l-glutamic acid monosodium salt reduces the harmful effect of lithium on the development of xenopus laevis embryos.many xenobiotics in the environment affect the human body in various ways. among those xenobiotics, lithium chloride (li, licl) and monosodium glutamate (l-glutamic acid monosodium salt, msg) compounds affect the crucial processes of stem cell differentiation, cell proliferation, developmental gene expression, and overall development in animals. in this study, we aimed to examine the developmental effects of exposure to flavor enhancer msg and lici medicament on xenopus embryos using the frog em ...202032705564
hplc reveals novel features of nucleoside and nucleobase homeostasis, nucleoside metabolism and nucleoside transport.humans possess three members of the cation-coupled concentrative nucleoside transporter cnt (slc 28) family, hcnt1-3: hcnt1 is selective for pyrimidine nucleosides but also transports adenosine, hcnt2 transports purine nucleosides and uridine, and hcnt3 transports both pyrimidine and purine nucleosides. hcnt1/2 transport nucleosides using the transmembrane na+ electrochemical gradient, while hcnt3 is both na+- and h+-coupled. by producing recombinant hcnt3 in xenopus laevis oocytes, we have used ...202032126230
cfap43 modulates ciliary beating in mouse and xenopus.malfunctions of motile cilia cause a variety of developmental defects and diseases in humans and animal model organisms. defects include impaired mucociliary clearance of the airways, sperm immotility, hydrocephalus and organ laterality. here, we characterize the evolutionary conserved cfap43 gene by loss-of-function experiments in the mouse and the frog xenopus laevis. cfap43 is expressed in tissues carrying motile cilia and acts as a target gene of the transcription factor foxj1, which is esse ...202031884020
insights regarding skin regeneration in non-amniote vertebrates: skin regeneration without scar formation and potential step-up to a higher level of regeneration.skin wounds are among the most common injuries in animals and humans. vertebrate skin is composed of an epidermis and dermis. after a deep skin injury in mammals, the wound heals, but the dermis cannot regenerate. instead, collagenous scar tissue forms to fill the gap in the dermis, but the scar does not function like the dermis and often causes disfiguration. in contrast, in non-amniote vertebrates, including fish and amphibians, the dermis and skin derivatives are regenerated after a deep skin ...202031831357
modulation by neonicotinoids of honeybee α1/chicken β2 hybrid nicotinic acetylcholine receptors expressed in xenopus laevis oocytes.neonicotinoids targeting insect nicotinic acetylcholine (ach) receptors (insect nachrs) are used for crop protection, but there is a concern about adverse effects on pollinators such as honeybees (apis mellifera). thus, we investigated the agonist actions of neonicotinoids (imidacloprid, thiacloprid and clothianidin) on a. mellifera α1 (amα1)/chicken β2 hybrid nachrs in xenopus laevis oocytes according to the subunit stoichiometry of (amα1)3(β2)2 and (amα1)2(β2)3 using voltage-clamp electrophysi ...202032448414
the mechanism of loop c-neonicotinoid interactions at insect nicotinic acetylcholine receptor α1 subunit predicts resistance emergence in pests.neonicotinoids selectively modulate insect nicotinic acetylcholine receptors (insect nachrs). studies have shown that serine with ability to form a hydrogen bond in loop c of some insect nachr α subunits and glutamate with a negative charge at the corresponding position in vertebrate nachrs may contribute to enhancing and reducing the neonicotinoid actions, respectively. however, there is no clear evidence what loop c properties underpin the target site actions of neonicotinoids. thus, we have i ...202032371996
evaluation of a multiplexed, multispecies nuclear receptor assay for chemical hazard assessment.sensitivity to potential endocrine disrupting chemicals in the environment varies across species and is influenced by sequence conservation of their nuclear receptor targets. here, we evaluated a multiplexed, in vitro assay testing receptors relevant to endocrine and metabolic disruption from five species. the trans-factorial™ system of human nuclear receptors was modified to include additional species: mouse (mus musculus), frog (xenopus laevis), zebrafish (danio rerio), chicken (gallus gallus) ...202033049310
polyunsaturated fatty acid-derived iks channel activators shorten the qt interval ex-vivo and in-vivo.we aimed to assess the ability of natural and modified polyunsaturated fatty acids (pufas) to shorten qt interval in ex-vivo and in-vivo guinea pig hearts.202032223014
organelle size scaling over embryonic development.cell division without growth results in progressive cell size reductions during early embryonic development. how do the sizes of intracellular structures and organelles scale with cell size and what are the functional implications of such scaling relationships? model organisms, in particular caenorhabditis elegans worms, drosophila melanogaster flies, xenopus laevis frogs, and mus musculus mice, have provided insights into developmental size scaling of the nucleus, mitotic spindle, and chromosom ...202032003549
impact of copper in xenopus laevis liver: histological damages and atp7b downregulation.copper is an essential micronutrient but its excess in the dietary can be toxic. both copper deficiency and abundance can occur in natural conditions and can lead to pathological dysfunctions. many of the toxic effects of copper, such as increased lipid peroxidation in cell membranes and dna damage, are due to its role in the generation of oxygen free radicals. copper is released into the environment by both natural sources and human activities and it can damage organisms and ecosystems. in the ...202031757510
effects of copper on the neuromasts of xenopus laevis.fish and aquatic amphibians possess neuromasts on the surface of their body that constitute the lateral line, a sensory system used to detect water displacement. copper is known to inactivate the neuromast organs of this system. copper-induced neuromast loss in african clawed frogs, xenopus laevis, was examined by exposing nieuwkoop-faber stage 54-55 larvae to copper concentrations of 0, 100, 200, 300, and 400 µg/l for 96 h, followed by an examination of neuromast counts, staining intensity, and ...202033180147
surface contraction waves or cell proliferation waves in the presumptive neurectoderm during amphibian gastrulation: mexican axolotl versus african clawed frog.this essay represents a critical analysis of the literary data on various types of waves occurring in the amphibian embryos during gastrulation. a surface contraction wave travels through the presumptive neurectoderm during mexican axolotl gastrulation. this wave coincides temporally and spatially with involution of the inducing chordomesoderm and with the prospective neural plate. by contrast, there is no similar surface contraction wave during african clawed frog gastrulation. however, the cla ...202033181236
trim-away mediated knock down uncovers a new function for lbh during gastrulation of xenopus laevis.we previously identified the protein lbh as necessary for cranial neural crest (cnc) cell migration in xenopus through the use of morpholinos. however, lbh is a maternally deposited protein and morpholinos achieve knockdowns through prevention of translation. in order to investigate the role of lbh in earlier embryonic events, we employed the new technique "trim-away" to degrade this maternally deposited protein. trim-away utilizes the e3 ubiquitin ligase trim21 to degrade proteins targeted with ...202033159936
ecotoxicological assessment of commercial boron nitride nanotubes toward xenopus laevis tadpoles and host-associated gut microbiota.despite the growing interest for boron nitride nanotubes (bnnt) due to their unique properties, data on the evaluation of the environmental risk potential of this emerging engineered nanomaterial are currently lacking. therefore, the ecotoxicity of a commercial form of bnnt (containing tubes, hexagonal-boron nitride, and boron) was assessed in vivo toward larvae of the amphibian xenopus laevis. following the exposure, multiple endpoints were measured in the tadpoles as well as in bacterial commu ...202033171057
an aryl hydrocarbon receptor from the caecilian gymnopis multiplicata suggests low dioxin affinity in the ancestor of all three amphibian orders.the aryl hydrocarbon receptor (ahr) plays pleiotropic roles in the development and physiology of vertebrates in conjunction with xenobiotic and endogenous ligands. it is best known for mediating the toxic effects of dioxin-like pollutants such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (tcdd). while most vertebrates possess at least one ahr that binds tcdd tightly, amphibian ahrs bind tcdd with very low affinity. previous analyses of ahrs from xenopus laevis (a frog; order anura) and ambystoma mexic ...202032858041
kunitz-type peptides from the sea anemone heteractis crispa demonstrate potassium channel blocking and anti-inflammatory activities.the kunitz/bpti peptide family includes unique representatives demonstrating various biological activities. electrophysiological screening of peptides hcrg1 and hcrg2 from the sea anemone heteractis crispa on six kv1.x channel isoforms and insect shaker ir channel expressed in xenopus laevis oocytes revealed their potassium channels blocking activity. hcrg1 and hcrg2 appear to be the first kunitz-type peptides from sea anemones blocking kv1.3 with ic50 of 40.7 and 29.7 nm, respectively. in addit ...202033158163
von willebrand factor d and egf domains is an evolutionarily conserved and required feature of blastemas capable of multitissue appendage regeneration.regenerative ability varies tremendously across species. a common feature of regeneration of appendages such as limbs, fins, antlers, and tails is the formation of a blastema-a transient structure that houses a pool of progenitor cells that can regenerate the missing tissue. we have identified the expression of von willebrand factor d and egf domains (vwde) as a common feature of blastemas capable of regenerating limbs and fins in a variety of highly regenerative species, including axolotl (amby ...202032163674
periodic albinism of a widely used albino mutant of xenopus laevis caused by deletion of two exons in the hermansky-pudlak syndrome type 4 gene.the periodic albino mutant of xenopus laevis is a recessive mutant, in which reduced amounts of melanin appear in the retinal pigment epithelium (rpe) and in melanophores at the late embryonic stage, after which both rpe and melanophores gradually depigment. three types of pigment cells (melanophores, iridophores, and xanthophores) have been reported to be affected in this albino. however, the causative gene of the periodic albinism remains unknown. hermansky-pudlak syndrome (hps) is an autosoma ...202033147376
disease-associated hcn4 v759i variant is not sufficient to impair cardiac pacemaking.the hyperpolarization-activated cation current if is a key determinant for cardiac pacemaker activity. it is conducted by subunits of the hyperpolarization-activated cyclic nucleotide-gated (hcn) channel family, of which hcn4 is predominant in mammalian heart. both loss-of-function and gain-of-function mutations of the hcn4 gene are associated with sinus node dysfunction in humans; however, their functional impact is not fully understood yet. here, we sought to characterize a hcn4 v759i variant ...202033095298
using an aquatic model, xenopus laevis, to uncover the role of chromodomain 1 in craniofacial disorders.the chromodomain family member chromodomain 1 (chd1) has been shown to have numerous critical molecular functions including transcriptional regulation, splicing, and dna repair. complete loss of function of this gene is not compatible with life. on the other hand, missense and copy number variants of chd1 can result in intellectual disabilities and craniofacial malformations in human patients including cleft palate and pilarowski-bjornsson syndrome. we have used the aquatic developmental model o ...202032918369
leishmania heme uptake involves lmflvcrb, a novel porphyrin transporter essential for the parasite.leishmaniasis comprises a group of neglected diseases caused by the protozoan parasite leishmania spp. as is the case for other trypanosomatid parasites, leishmania is auxotrophic for heme and must scavenge this essential compound from its human host. in mammals, the slc transporter flvcr2 mediates heme import across the plasma membrane. herein we identify and characterize leishmania major flvcrb (lmflvcrb), the first member of the flvcr family studied in a non-metazoan organism. this protein lo ...202031372684
adverse effects of fly ashes used as immobilizing agents for highly metal-contaminated soils on xenopus laevis oocytes survival and maturation-a study performed in the north of france with field soil extracts.amphibians are now recognized as the most endangered group. one of this decline causes is the degradation of their habitat through direct contamination of water, soil leaching, or runoff from surrounding contaminated soils and environments. in the north of france, the extensive industrial activities resulted in massive soil contamination by metal compounds. mineral amendments were added to soils to decrease trace metal mobility. because of the large areas to be treated, the use of inexpensive in ...202030875069
effects of glyphosate and a commercial formulation roundup® exposures on maturation of xenopus laevis oocytes.pesticides are often found at high concentrations in small ponds near agricultural field where amphibians are used to live and reproduce. even if there are many studies on the impacts of phytopharmaceutical active ingredients in amphibian toxicology, only a few are interested in the earlier steps of their life cycle. while their populations are highly threatened with extinction. the aim of this work is to characterize the effects of glyphosate and its commercial formulation roundup® gt max on th ...202030835066
microsampling capillary electrophoresis mass spectrometry enables single-cell proteomics in complex tissues: developing cell clones in live xenopus laevis and zebrafish embryos.label-free single-cell proteomics by mass spectrometry (ms) is currently incompatible with complex tissues without requiring cell culturing, single-cell dissection, or tissue dissociation. we here report the first example of label-free single-cell ms-based proteomics directly in single cells in live vertebrate embryos. our approach integrates optically guided in situ subcellular capillary microsampling, one-pot extraction-digestion of the collected proteins, peptide separation by capillary elect ...201930827088
conditional demyelination and remyelination in a transgenic xenopus laevis.multiple sclerosis (ms) is the first cause of acquired disability progression in the young adult. pathology of ms associates inflammation, demyelination, and neurodegeneration. the development of immunotherapies, by reducing the relapse rate, has profoundly impacted short-term prognosis and patients' quality of life. these anti-inflammatory medications, however, have not proven to be sufficient to prevent long-term disability progression, resulting from axonal transection and neuronal damage, co ...201930820903
the c-terminus of the retinal homeobox (rax) gene product modulates transcription in a context-dependent manner.the evolutionarily conserved retinal homeobox (rax) transcription factor is essential for normal eye development in all vertebrates. despite rax's biologic significance, the molecular mechanisms underlying rax molecular function as a transcriptional regulator are poorly defined. the rax gene encodes a conserved octapeptide motif (op) near the n-terminus and several conserved regions in the c-terminus of unknown function, including the orthopedia, aristaless, rax (oar) domain and the rx domain. t ...201930820152
more than just a bandage: closing the gap between injury and appendage regeneration.the remarkable regenerative capabilities of amphibians have captured the attention of biologists for centuries. the frogs xenopus laevis and xenopus tropicalis undergo temporally restricted regenerative healing of appendage amputations and spinal cord truncations, injuries that are both devastating and relatively common in human patients. rapidly expanding technological innovations have led to a resurgence of interest in defining the factors that enable regenerative healing, and in coupling thes ...201930800076
the wnt inhibitor dkk1 is required for maintaining the normal cardiac differentiation program in xenopus laevis.wnt proteins can activate different intracellular signaling pathways. these pathways need to be tightly regulated for proper cardiogenesis. the canonical wnt/β-catenin inhibitor dkk1 has been shown to be sufficient to trigger cardiogenesis in gain-of-function experiments performed in multiple model systems. loss-of-function studies however did not reveal any fundamental function for dkk1 during cardiogenesis. using xenopus laevis as a model we here show for the first time that dkk1 is required f ...201930797757
fluorescent analogues of bekm-1 with high and specific activity against the herg channel.peptidic toxins that target specifically mammalian channels and receptors can be found in the venom of animals. these toxins are rarely used directly as tools for biochemical experiments, and need to be modified via the attachment of chemical groups (e.g., radioactive or fluorescent moieties). ideally, such modifications should maintain the toxin specificity and affinity for its target. with the goal of obtaining fluorescent derivatives of bekm-1, a toxin from the scorpion species buthus eupeus ...201932550567
rho flares repair local tight junction leaks.tight junctions contribute to epithelial barrier function by selectively regulating the quantity and type of molecules that cross the paracellular barrier. experimental approaches to evaluate the effectiveness of tight junctions are typically global, tissue-scale measures. here, we introduce zinc-based ultrasensitive microscopic barrier assay (znumba), which we used in xenopus laevis embryos to visualize short-lived, local breaches in epithelial barrier function. these breaches, or leaks, occur ...201930773490
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