Publications

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water-soluble variant of human lynx1 positively modulates synaptic plasticity and ameliorates cognitive impairment associated with α7-nachr dysfunction.lynx1 is a gpi-tethered protein colocalized with nicotinic acetylcholine receptors (nachrs) in the brain areas important for learning and memory. previously, we demonstrated that at low micromolar concentrations the water-soluble lynx1 variant lacking gpi-anchor (ws-lynx1) acts on α7-nachrs as a positive allosteric modulator. we hypothesized that ws-lynx1 could be used for improvement of cognitive processes dependent on nachrs. here we showed that 2 µm ws-lynx1 increased the acetylcholine-evoked ...202032222974
effects of syntaxins 2, 3, and 4 on rat and human epithelial sodium channel (enac) in xenopus laevis oocytes.syntaxins are snare proteins and may play a role in epithelial sodium channel (enac) trafficking. the aim of the present study was to investigate the effects of syntaxin 2 (stx2), syntaxin 3 (stx3), and syntaxin 4 (stx4) on rat (renac) and human enac (henac). co-expression of renac and stx3 or stx4 in xenopus laevis oocytes increased amiloride-sensitive whole-cell currents (δiami) on average by 50% and 135%, respectively, compared to oocytes expressing renac alone. in contrast, stx2 had no signi ...202032221667
effect assessment of reclaimed water and carbamazepine exposure on the thyroid axis of x. laevis: apical and histological effects.there is increasing environmental concern about the constant presence of pharmaceuticals and personal care products (ppcps) in surface water, generally attributed to water discharge from wastewater treatment plants (wwtps) that are unable to completely remove these compounds. the slight, but continuous, presence of these contaminants in reclaimed water (rw) poses a risk of chronic and sublethal toxicity, and the thyroid axis can likely be a target of many of these ppcps. in this work, we address ...202032220735
defining the specific pathogen-free state of xenopus using taqman assays.colonies of valuable inbred and transgenic laboratory-reared xenopus frogs maintained for research constitute naïve populations of animals susceptible to some opportunistic infectious diseases. therefore, it is prudent to characterize any new animal acquisitions before introduction into an existing colony as a biosecurity measure to preclude the concurrent introduction of an infectious microorganism associated with the new animal(s). in addition, some pathogens of xenopus, such as chlamydia and ...202032213545
action potentials in xenopus oocytes triggered by blue light.voltage-gated sodium (na+) channels are responsible for the fast upstroke of the action potential of excitable cells. the different α subunits of na+ channels respond to brief membrane depolarizations above a threshold level by undergoing conformational changes that result in the opening of the pore and a subsequent inward flux of na+. physiologically, these initial membrane depolarizations are caused by other ion channels that are activated by a variety of stimuli such as mechanical stretch, te ...202032211871
the actin-family protein arp4 is a novel suppressor for the formation and functions of nuclear f-actin.the crosstalk between actin and actin-related proteins (arps), namely arp2 and arp3, plays a central role in facilitating actin polymerization in the cytoplasm and also in the nucleus. nuclear f-actin is required for transcriptional regulation, double-strand break repair, and nuclear organization. the formation of nuclear f-actin is highly dynamic, suggesting the involvement of positive and negative regulators for nuclear actin polymerization. while actin assembly factors for nuclear f-actin hav ...202032204557
mechanical stress regulates epithelial tissue integrity and stiffness through the fgfr/erk2 signaling pathway during embryogenesis.physical forces generated by tissue-tissue interactions are a critical component of embryogenesis, aiding the formation of organs in a coordinated manner. in this study, using xenopus laevis embryos and phosphoproteome analyses, we uncover the rapid activation of the mitogen-activated protein (map) kinase erk2 upon stimulation with centrifugal, compression, or stretching force. we demonstrate that erk2 induces the remodeling of cytoskeletal proteins, including f-actin, an embryonic cadherin c-ca ...202032187556
targeted pathway-based in vivo testing using thyroperoxidase inhibition to evaluate plasma thyroxine as a surrogate metric of metamorphic success in model amphibian xenopus laevis.chemical safety evaluation is in the midst of a transition from traditional whole-animal toxicity testing to molecular pathway-based in vitro assays and in silico modeling. however, to facilitate the shift in reliance on apical effects for risk assessment to predictive surrogate metrics having characterized linkages to chemical mechanisms of action, targeted in vivo testing is necessary to establish these predictive relationships. in this study, we demonstrate a means to predict thyroid-related ...202032176285
ssrp1-mediated histone h1 eviction promotes replication origin assembly and accelerated development.in several metazoans, the number of active replication origins in embryonic nuclei is higher than in somatic ones, ensuring rapid genome duplication during synchronous embryonic cell divisions. high replication origin density can be restored by somatic nuclear reprogramming. however, mechanisms underlying high replication origin density formation coupled to rapid cell cycles are poorly understood. here, using xenopus laevis, we show that ssrp1 stimulates replication origin assembly on somatic ch ...202032165637
evaluation of effective and practical euthanasia methods for larval african clawed frogs (xenopus laevis).larval, or tadpole-stage xenopus laevis frogs are a popular research model for developmental biology and disease studies. existing euthanasia guidance documents offer recommendations for both eggs and adult stages, yet do not specifically address the larval stage. data evaluating effective euthanasia methods for groups of x. laevis tadpoles would therefore be useful. the goal of the current study was to evaluate the efficacy of various immersion euthanasia procedures on tadpoles: tricaine methan ...202032164797
amphibian thalamic nuclear organization during larval development and in the adult frog xenopus laevis: genoarchitecture and hodological analysis.the early patterning of the thalamus during embryonic development defines rostral and caudal progenitor domains, which are conserved from fishes to mammals. however, the subsequent developmental mechanisms that lead to the adult thalamic configuration have only been investigated for mammals and other amniotes. in this study, we have analyzed in the anuran amphibian xenopus laevis (an anamniote vertebrate), through larval and postmetamorphic development, the progressive regional expression of spe ...202032162311
rapid shifts in the temperature dependence of locomotor performance in an invasive frog, xenopus laevis, implications for conservation.temperature is a critical abiotic factor impacting all aspects of the biology of organisms, especially in ectotherms. as such, it is an important determinant of the potential invasive ability of organisms and may limit population expansion unless organisms can physiologically respond to changes in temperature either through plasticity or by adapting to their novel environment. here, we studied the african clawed frog, xenopus laevis, which has become invasive on a global scale. we compared adult ...202032159752
reversible thiol oxidation inhibits the mitochondrial atp synthase in xenopus laevis oocytes.oocytes are postulated to repress the proton pumps (e.g., complex iv) and atp synthase to safeguard mitochondrial dna homoplasmy by curtailing superoxide production. whether the atp synthase is inhibited is, however, unknown. here we show that: oligomycin sensitive atp synthase activity is significantly greater (~170 vs. 20 nmol/min-1/mg-1) in testes compared to oocytes in xenopus laevis (x. laevis). since atp synthase activity is redox regulated, we explored a regulatory role for reversible thi ...202032150908
fluorescent calcium imaging and subsequent in situ hybridization for neuronal precursor characterization in xenopus laevis.spontaneous intracellular calcium activity can be observed in a variety of cell types and is proposed to play critical roles in a variety of physiological processes. in particular, appropriate regulation of calcium activity patterns during embryogenesis is necessary for many aspects of vertebrate neural development, including proper neural tube closure, synaptogenesis, and neurotransmitter phenotype specification. while the observation that calcium activity patterns can differ in both frequency ...202032150168
quantitative capillary zone electrophoresis-mass spectrometry reveals the n-glycome developmental plan during vertebrate embryogenesis.glycans are known to be involved in many biological processes, while little is known about the expression of n-glycans during vertebrate development. we now report the first quantitative studies of both the expression of n-linked glycans at six early development stages and the expression of n-glycosylated peptides at two early development stages in xenopus laevis, the african clawed frog. n-glycans were labeled with isobaric tandem mass tags, pooled, separated by capillary electrophoresis, and c ...202032149324
testing for thyroid hormone disruptors, a review of non-mammalian in vivo models.thyroid hormones (ths) play critical roles in profound changes in many vertebrates, notably in mammalian neurodevelopment, although the precise molecular mechanisms of these fundamental biological processes are still being unravelled. environmental and health concerns prompted the development of chemical safety testing and, in the context of endocrine disruption, identification of thyroid hormone axis disrupting chemicals (thadcs) remains particularly challenging. as various molecules are known ...202032147522
recent progress of in-cell nmr of nucleic acids in living human cells.the inside of living cells is highly crowded with biological macromolecules. it has long been considered that the properties of nucleic acids and proteins, such as their structures, dynamics, interactions, and enzymatic activities, in intracellular environments are different from those under in vitro dilute conditions. in-cell nmr is a robust and powerful method used in the direct measurement of those properties in living cells. however, until 2 years ago, in-cell nmr was limited to xenopus laev ...202032144741
miniaturized filter-aided sample preparation (micro-fasp) method for high throughput, ultrasensitive proteomics sample preparation reveals proteome asymmetry in xenopus laevis embryos.we report a miniaturized filter aided sample preparation method (micro-fasp) for low-loss preparation of submicrogram proteomic samples. the method employs a filter with ∼0.1 mm2 surface area, reduces the total volume of reagents to <10 μl, and requires only two sample transfer steps. the method was used to generate 25 883 unique peptides and 3069 protein groups from 1000 mcf-7 cells (∼100 ng protein content), and 13 367 peptides and 1895 protein groups were identified from 100 mcf-7 cells (∼10 ...202032125139
activation of mouse nbce1-b by xenopus laevis and mouse irbits: role of the variable nt appendage of irbits.the ip3 receptor binding protein released with inositol 1,4,5-trisphosphate (irbit) plays important roles in the regulation of intracellular ca2+ signaling and intracellular ph. the mammals express two irbit paralogs, i.e., irbit1 (encoded by ahcyl1) and irbit2 (encoded by ahcyl2). the clawed frog xenopus laevis oocyte is widely used for biophysical studies on ion channels and transporters. it remains unknown whether endogenous irbit is expressed in xenopus oocytes. here, we cloned from frog ooc ...202032119862
chromatin accessibility and histone acetylation in the regulation of competence in early development.as development proceeds, inductive cues are interpreted by competent tissues in a spatially and temporally restricted manner. while key inductive signaling pathways within competent cells are well-described at a molecular level, the mechanisms by which tissues lose responsiveness to inductive signals are not well understood. localized activation of wnt signaling before zygotic gene activation in xenopus laevis leads to dorsal development, but competence to induce dorsal genes in response to wnts ...202032119833
regeneration enhancers: a clue to reactivation of developmental genes.during tissue and organ regeneration, cells initially detect damage and then alter nuclear transcription in favor of tissue/organ reconstruction. until recently, studies of tissue regeneration have focused on the identification of relevant genes. these studies show that many developmental genes are reused during regeneration. concurrently, comparative genomics studies have shown that the total number of genes does not vastly differ among vertebrate taxa. moreover, functional analyses of developm ...202032096563
microtubule minus-end binding protein camsap2 and kinesin-14 motor kifc3 control dendritic microtubule organization.neuronal dendrites are characterized by an anti-parallel microtubule organization. the mixed oriented microtubules promote dendrite development and facilitate polarized cargo trafficking; however, the mechanism that regulates dendritic microtubule organization is still unclear. here, we found that the kinesin-14 motor kifc3 is important for organizing dendritic microtubules and to control dendrite development. the kinesin-14 motor proteins (drosophila melanogaster ncd, saccharomyces cerevisiae k ...202032084403
stem cell development involves divergent thyroid hormone receptor subtype expression and epigenetic modifications in the xenopus metamorphosing intestine.in the intestine during metamorphosis of the frog xenopus laevis, most of the larval epithelial cells are induced to undergo apoptosis by thyroid hormone (th), and under continued th action, the remaining epithelial cells dedifferentiate into stem cells (scs), which then newly generate an adult epithelium analogous to the mammalian intestinal epithelium. previously, we have shown that the precursors of the scs that exist in the larval epithelium as differentiated absorptive cells specifically ex ...202032084349
14-3-3 targets keratin intermediate filaments to mechanically sensitive cell-cell contacts.intermediate filament (if) cytoskeletal networks simultaneously support mechanical integrity and influence signal transduction pathways. marked remodeling of the keratin if network accompanies collective cellular morphogenetic movements that occur during early embryonic development in the frog xenopus laevis. while this reorganization of keratin is initiated by force transduction on cell-cell contacts mediated by c-cadherin, the mechanism by which keratin filament reorganization occurs remains p ...202032074004
relationship between the induced iron overload model and hepatic erythropoiesis in xenopus laevis.iron is an essential element for hemoglobin synthesis during erythropoiesis. iron overload, in contrast, adversely affects erythropoiesis and causes organ dysfunction. research using various animal models may help to elucidate pathophysiological mechanisms induced by excess iron. in the present study, we evaluated the relationship between iron metabolism and erythropoietic activity in the african clawed frog, xenopus laevis. in x. laevis, both erythropoiesis and iron metabolism occur in the live ...202032068375
ashwin gene expression profiles in oocytes, preimplantation embryos, and fetal and adult bovine tissues.the ashwin gene, originally identified in xenopuslaevis, was found to be expressed first in the neural plate and later in the embryonic brain, eyes, and spinal cord. functional studies of ashwin suggest that it participates in cell survival and anteroposterior patterning. furthermore, ashwin is expressed zygotically in this species, which suggests that it participates in embryonic development. nevertheless, the expression of this gene has not been studied in mammals. thus, the aim of this study ...202032054057
ncbp2 modulates neurodevelopmental defects of the 3q29 deletion in drosophila and xenopus laevis models.the 1.6 mbp deletion on chromosome 3q29 is associated with a range of neurodevelopmental disorders, including schizophrenia, autism, microcephaly, and intellectual disability. despite its importance towards neurodevelopment, the role of individual genes, genetic interactions, and disrupted biological mechanisms underlying the deletion have not been thoroughly characterized. here, we used quantitative methods to assay drosophila melanogaster and xenopus laevis models with tissue-specific individu ...202032053595
interactions of deet and novel repellents with mosquito odorant receptors.the carboxamide n,n-di-ethyl-meta-toluamide (deet) is the most effective and widely used insect repellent today. however, drawbacks concerning the efficacy and the safety of the repellent have led to efforts to design new classes of insect repellents. through quantitative structure-activity relationships, chemists have discovered two chemical groups of novel repellents: the acylpiperidines and the carboxamides, with the acylpiperidines generally more potent in biological assays. although the exa ...202032048720
chlorpromazine binding to the pas domains uncovers the effect of ligand modulation on eag channel activity.ether-a-go-go (eag) potassium selective channels are major regulators of neuronal excitability and cancer progression. eag channels contain a per-arnt-sim (pas) domain in their intracellular n-terminal region. the pas domain is structurally similar to the pas domains in non-ion channel proteins, where these domains frequently function as ligand-binding domains. despite the structural similarity, it is not known whether the pas domain can regulate eag channel function via ligand binding. here, us ...202032047112
2,2',4,4'-tetrabromodipheny ether (bde-47) disrupts gonadal development of the africa clawed frog (xenopus laevis).previous studies have shown that bde-47, one of the most abundant polybrominated diphenyl ethers (pbdes) congeners, has a weak estrogenic activity, but it has remained unclear whether bde-47 disrupts gonadal development and causes male-to-female sex reversal in lower vertebrates, with limited and controversial data. the present study aimed to determine the effects of bde-47 on gonadal development in xenopus laevis, a model amphibian species for studying adverse effects of estrogenic chemicals on ...202032045789
the grapevine nae sodium exclusion locus encodes sodium transporters with diverse transport properties and localisation.grapevine (vitis vinifera l.) is a valuable crop for human consumption and wine production, and is prone to suffering from salinity stress in arid regions or when exposed to low quality irrigation water. a previous study identified a quantitative trait locus (qtl) nae, containing six high-affinity potassium transporter 1 genes, that was associated with shoot na+ exclusion in grapevine. while hkt1;1 was predicted to be the most likely gene within this qtl to encode for this important salinity tol ...202032044673
all-fibre supercontinuum laser for in vivo multispectral photoacoustic microscopy of lipids in the extended near-infrared region.among the numerous endogenous biological molecules, information on lipids is highly coveted for understanding both aspects of developmental biology and research in fatal chronic diseases. due to the pronounced absorption features of lipids in the extended near-infrared region (1650-1850 nm), visualisation and identification of lipids become possible using multi-spectral photoacoustic (optoacoustic) microscopy. however, the spectroscopic studies in this spectral region require lasers that can pro ...202032042589
multistep peripherin-2/rds self-assembly drives membrane curvature for outer segment disk architecture and photoreceptor viability.rod and cone photoreceptor outer segment (os) structural integrity is essential for normal vision; disruptions contribute to a broad variety of retinal ciliopathies. oss possess many hundreds of stacked membranous disks, which capture photons and scaffold the phototransduction cascade. although the molecular basis of os structure remains unresolved, recent studies suggest that the photoreceptor-specific tetraspanin, peripherin-2/rds (p/rds), may contribute to the highly curved rim domains at dis ...202032041874
low concentrations of tetrabromobisphenol a disrupt notch signaling and intestinal development in in vitro and in vivo models.tetrabromobisphenol a (tbbpa) was recently reported to upregulate notch target gene expression in embryonic stem cells differentiating to neurons in vitro, implying activation on notch signaling, a crucial signaling involved in multiple organ development and homeostasis.the present study aimed to determine whether tbbpa at low concentrations can disrupt notch signaling in the intestine and subsequently its development using in vitro and in vivo models, given tbbpa uptake mainly via the intestine ...202032041402
xenopus deep cell aggregates: a 3d tissue model for mesenchymal-to-epithelial transition.mesenchymal-to-epithelial transition (met) describes the ability of loosely associated migratory cells to form a more adherent sheet-like assembly of cells. met is a conserved motif occurring throughout organogenesis and plays a key role in regeneration and cancer metastasis, and is the first step in producing induced pluripotent stem cells (ipscs). to resolve fundamental biological questions about met, its relation to epithelial-to-mesenchymal transition, and to explore met's role in tissue ass ...202132939727
characterizing channelrhodopsin channel properties via two-electrode voltage clamp and kinetic modeling.two-electrode voltage clamp (tevc) is a preferred electrophysiological technique used to study gating kinetics and ion selectivity of light-activated channelrhodopsins (chrs). the method uses two intracellular microelectrodes to hold, or clamp, the membrane potential at a specific value and measure the flow of ions across the plasma membrane. here, we describe the use of tevc and a simple solution exchange protocol to measure cation selectivity and analyze gating kinetics of the c1c2 chimera exp ...202132865738
epigenetic control of myeloid cells behavior by histone deacetylase activity (hdac) during tissue and organ regeneration in xenopus laevis.in the present work we have focused on the histone deacetylase (hdac) control of myeloid cells behavior during xenopus tail regeneration. here we show that myeloid differentiation is crucial to modulate the regenerative ability of xenopus tadpoles in a hdac activity-dependent fashion. hdac activity inhibition during the first wave of myeloid differentiation disrupted myeloid cells dynamics in the regenerative bud as well the mrna expression pattern of myeloid markers, such as lurp, mpox, spib an ...202132858087
clearance of activity-evoked k+ transients and associated glia cell swelling occur independently of aqp4: a study with an isoform-selective aqp4 inhibitor.the mammalian brain consists of 80% water, which is continuously shifted between different compartments and cellular structures by mechanisms that are, to a large extent, unresolved. aquaporin 4 (aqp4) is abundantly expressed in glia and ependymal cells of the mammalian brain and has been proposed to act as a gatekeeper for brain water dynamics, predominantly based on studies utilizing aqp4-deficient mice. however, these mice have a range of secondary effects due to the gene deletion. an efficie ...202132506554
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