Publications

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amphibian (xenopus laevis) interleukin-8 (cxcl8): a perspective on the evolutionary divergence of granulocyte chemotaxis.the glutamic acid-leucine-arginine (elr) motif is a hallmark feature shared by mammalian inflammatory cxc chemokines such the granulocyte chemo-attractant cxcl8 (interleukin-8, il-8). by contrast, most teleost fish inflammatory chemokines lack this motif. interestingly, the amphibian xenopus laevis encodes multiple isoforms of cxcl8, one of which (cxcl8a) possesses an elr motif, while another (cxcl8b) does not. these cxcl8 isoforms exhibit distinct expression patterns during frog development and ...201830258441
molecular determinants of α-conotoxin potency for inhibition of human and rat α6β4 nicotinic acetylcholine receptors.nicotinic acetylcholine receptors (nachrs) containing α6 and β4 subunits are expressed by dorsal root ganglion neurons and have been implicated in neuropathic pain. rodent models are often used to evaluate the efficacy of analgesic compounds, but species differences may affect the activity of some nachr ligands. a previous candidate α-conotoxin-based therapeutic yielded promising results in rodent models, but failed in human clinical trials, emphasizing the importance of understanding species di ...201830249616
the balance of two opposing factors mad and myc regulates cell fate during tissue remodeling.cell proliferation and differentiation are two distinct yet coupled processes in development in diverse organisms. understanding the molecular mechanisms that regulate this process is a central theme in developmental biology. the intestinal epithelium is a highly complex tissue that relies on the coordination of cell proliferation within the crypts and apoptosis mainly at the tip of the villi, preservation of epithelial function through differentiation, and homeostatic cell migration along the c ...201830237868
two tier hox collinearity mediates vertebrate axial patterning.a two tier mechanism mediates hox collinearity. besides the familiar collinear chromatin modification within each hox cluster (nanocollinearity), there is also a macrocollinearity tier. individual hox clusters and individual cells are coordinated and synchronized to generate multiscale (macro and nano) collinearity in the early vertebrate embryo. macro-collinearity is mediated by three non-cell autonomous hox-hox interactions. these mediate temporal collinearity in early nom (non-organizer mesod ...201830234110
dscam differentially modulates pre- and postsynaptic structural and functional central connectivity during visual system wiring.proper patterning of dendritic and axonal arbors is a critical step in the formation of functional neuronal circuits. developing circuits rely on an array of molecular cues to shape arbor morphology, but the underlying mechanisms guiding the structural formation and interconnectivity of pre- and postsynaptic arbors in real time remain unclear. here we explore how down syndrome cell adhesion molecule (dscam) differentially shapes the dendritic morphology of central neurons and their presynaptic r ...201830219101
systematic variation of the benzoylhydrazine moiety of the glun2a selective nmda receptor antagonist tcn-201.glun2a containing n-methyl-d-aspartate receptors (nmdars) are important ion channels in the central nervous system and highly involved in several different neurophysiological but also neuropathophysiological processes. however, current understanding of the contribution of glun2a containing nmdars in these processes is incomplete. therefore, highly selective compounds are required to further investigate these ion channels. in 2010, tcn-201 (2), one of the first selective negative allosteric modul ...201830218911
bighead is a wnt antagonist secreted by the xenopus spemann organizer that promotes lrp6 endocytosis.the xenopus laevis embryo has been subjected to almost saturating screens for molecules specifically expressed in dorsal spemann organizer tissue. in this study, we performed high-throughput rna sequencing of ectodermal explants, called animal caps, which normally give rise to epidermis. we analyzed dissociated animal cap cells that, through sustained activation of mapk, differentiate into neural tissue. we also microinjected mrnas for cerberus, chordin, fgf8, bmp4, wnt8, and xnr2, which induce ...201830209221
a review of interventions against fetal alcohol spectrum disorder targeting oxidative stress.fetal alcohol spectrum disorder is caused by maternal ethanol exposure; it causes physical, behavioral, cognitive, and neural impairments (murawski et al., 2015). mechanisms of fasd causing damage are not yet fully elucidated. oxidative stress might be one of its mechanisms (henderson et al., 1995). yet no effective treatment against fasd has been found other than ethanol abstention (long et al., 2010).201830205148
in vitro analyses of novel hcn4 gene mutations.the hyperpolarization-activated cyclic nucleotide-gated cation channel hcn4 contributes significantly to the generation of basic cardiac electrical activity in the sinus node and is a mediator of modulation by β-adrenergic stimulation. heterologous expression of sick sinus syndrome (sss) and bradycardia associated mutations within the human hcn4 gene results in altered channel function. the main aim was to describe the functional characterization of three (two novel and one known) missense mutat ...201830196304
inward rectifier potassium (kir) channels in the soybean aphid aphis glycines: functional characterization, pharmacology, and toxicology.inward rectifier k+ (kir) channels contribute to a variety of physiological processes in insects and are emerging targets for insecticide development. previous studies on insect kir channels have primarily focused on dipteran species (e.g., mosquitoes, fruit flies). here we identify and functionally characterize kir channel subunits in a hemipteran insect, the soybean aphid aphis glycines, which is an economically important insect pest and vector of soybeans. from the transcriptome and genome of ...201830196125
a dual-app nucleoside probe provides structural insights into the human telomeric overhang in live cells.understanding the topology adopted by individual g-quadruplex (gq)-forming sequences in vivo and targeting a specific gq motif among others in the genome will have a profound impact on gq-directed therapeutic strategies. however, this remains a major challenge as most of the tools poorly distinguish different gq conformations and are not suitable for both cell-free and in-cell analysis. here, we describe an innovative probe design to investigate gq conformations and recognition in both cell-free ...201830192541
multiscale analysis of architecture, cell size and the cell cortex reveals cortical f-actin density and composition are major contributors to mechanical properties during convergent extension.the large-scale movements that construct complex three-dimensional tissues during development are governed by universal physical principles. fine-grained control of both mechanical properties and force production is crucial to the successful placement of tissues and shaping of organs. embryos of the frog xenopus laevis provide a dramatic example of these physical processes, as dorsal tissues increase in young's modulus by six-fold to 80 pascal over 8 h as germ layers and the central nervous syst ...201830190279
draft genome of dugesia japonica provides insights into conserved regulatory elements of the brain restriction gene nou-darake in planarians.planarians are non-parasitic platyhelminthes (flatworms) famous for their regeneration ability and for having a well-organized brain. dugesia japonica is a typical planarian species that is widely distributed in the east asia. extensive cellular and molecular experimental methods have been developed to identify the functions of thousands of genes in this species, making this planarian a good experimental model for regeneration biology and neurobiology. however, no genome-level information is ava ...201830181897
the cytoskeletal protein zyxin interacts with the zinc-finger transcription factor zic1 and plays the role of a scaffold for gli1 and zic1 interactions during early development of xenopus laevis.we have shown recently that the cytoskeletal protein zyxin participates in the fine tuning of the neural plate pattering in xenopus laevis embryos by modulating activity of one of the effectors of hedgehog (shh) signaling cascade, the transcription factor gli1. in the present work, we show that zyxin can also interact with the potential modulator of the shh pathway, the transcription factor zic1. the interaction of proteins occurs primarily by mean of the zinc-finger domain of zic1 and 2nd lim d ...201830180953
a single xlf dimer bridges dna ends during nonhomologous end joining.nonhomologous end joining (nhej) is the primary pathway of dna double-strand-break repair in vertebrate cells, yet how nhej factors assemble a synaptic complex that bridges dna ends remains unclear. to address the role of xrcc4-like factor (xlf) in synaptic-complex assembly, we used single-molecule fluorescence imaging in xenopus laevis egg extract, a system that efficiently joins dna ends. we found that a single xlf dimer binds dna substrates just before the formation of a ligation-competent sy ...201830177755
morphomechanical reactions and mechanically stressed structures in amphibian embryos, as related to gastrulation and axial organs formation.reactions of embryonic tissues to a distributed and concentrated stretching are described and compared with the mechanics of the normal gastrulation movements. a role of mechanically stressed dynamic cell structures in the gastrulation, demarcation of notochord borders and in providing proportionality of the axial rudiments is demonstrated. a morphomechanical scheme of amphibian gastrulation is presented.201830321583
reconstitution of cell-cycle oscillations in microemulsions of cell-free xenopus egg extracts.real-time measurement of oscillations at the single-cell level is important to uncover the mechanisms of biological clocks. although bulk extracts prepared from xenopus laevis eggs have been powerful in dissecting biochemical networks underlying the cell-cycle progression, their ensemble average measurement typically leads to a damped oscillation, despite each individual oscillator being sustained. this is due to the difficulty of perfect synchronization among individual oscillators in noisy bio ...201830320763
assembly of protein complexes restricts diffusion of wnt3a proteins.members of the wnt protein family play roles in many aspects of embryogenesis and homeostasis. despite their biological significance, characteristics of wnt proteins still remain unclear, mainly due to their insolubility after the removal of serum. here we examine wnt proteins in serum-containing media by using analytical ultracentrifugation with a fluorescence detection system. this analysis reveals that wnt3a assembles into high-molecular-weight complexes that become dissociable by interaction ...201830320232
polystyrene microplastics did not affect body growth and swimming activity in xenopus laevis tadpoles.a growing number of studies have highlighted the contamination and the effects towards organisms of diverse microplastics (μps) in the marine environment. surprisingly, although the main sources of μps for marine environments are inland surface waters, the information on the occurrence and the effects of μps in freshwater ecosystems is still scant. thus, the aim of the present work is to investigate the ingestion and possible adverse effects due to the exposure to polystyrene μps (psμps; ø = 3 μ ...201830317408
calcineurin promotes apc/c activation at meiotic exit by acting on both xerp1 and cdc20.vertebrate oocytes await fertilization arrested at metaphase of the second meiotic division. fertilization triggers a transient calcium wave, which induces the activation of the anaphase-promoting complex/cyclosome (apc/c) and its co-activator cdc20 resulting in the destruction of cyclin b and hence meiotic exit. two calcium-dependent enzymes are implicated in fertilization-induced apc/ccdc20 activation: calcium-/calmodulin-dependent kinase type ii (camkii) and calcineurin (can). while the role ...201830373936
assessment of the complex refractive indices of xenopus laevis sciatic nerve for the optimization of optical (nir) neurostimulation.despite an increasing interest in the use of light for neural stimulation, there is little information on how it interacts with neural tissue. the choice of wavelength in most of the optical stimulation literature is based on already available light sources designed for other applications. this paper is the first one to report the complex refractive index of the sciatic nerve of xenopus laevis, which is a crucial parameter for identifying the optimal wavelength of optical stimuli. the xenopus la ...201830371379
the receptor-like pseudokinase ghr1 is required for stomatal closure.guard cells control the aperture of stomatal pores to balance photosynthetic carbon dioxide uptake with evaporative water loss. stomatal closure is triggered by several stimuli that initiate complex signaling networks to govern the activity of ion channels. activation of slow anion channel1 (slac1) is central to the process of stomatal closure and requires the leucine-rich repeat receptor-like kinase (lrr-rlk) guard cell hydrogen peroxide-resistant1 (ghr1), among other signaling components. here ...201830361234
divergent subgenome evolution after allopolyploidization in african clawed frogs (xenopus).whole genome duplication (wgd), the doubling of the nuclear dna of a species, contributes to biological innovation by creating genetic redundancy. one mode of wgd is allopolyploidization, wherein each genome from two ancestral species becomes a 'subgenome' of a polyploid descendant species. the evolutionary trajectory of a duplicated gene that arises from wgd is influenced both by natural selection that may favour redundant, new or partitioned functions, and by gene silencing (pseudogenization). ...201830341989
synthetic light-activated ion channels for optogenetic activation and inhibition.optogenetic manipulation of cells or living organisms became widely used in neuroscience following the introduction of the light-gated ion channel channelrhodopsin-2 (chr2). chr2 is a non-selective cation channel, ideally suited to depolarize and evoke action potentials in neurons. however, its calcium (ca2+) permeability and single channel conductance are low and for some applications longer-lasting increases in intracellular ca2+ might be desirable. moreover, there is need for an efficient lig ...201830333716
multiple combinations of rdl subunits diversify the repertoire of gaba receptors in the honey bee parasite varroa destructor.in insects, γ-aminobutyric acid (gaba) is the major inhibitory neurotransmitter, and gaba-gated ion channels are the target of different classes of insecticides, including fipronil. we report here the cloning of six subunits (four rdl, one lcch3, and one grd) that constitute the repertoire of the gaba-gated ion channel family of the varroa mite (varroa destructor), a honey bee ectoparasite. we also isolated a truncated grd subunit with a premature stop codon. we found that when expressed in xeno ...201830333227
emerin induces nuclear breakage in xenopus extract and early embryos.emerin is an inner nuclear membrane protein often mutated in emery-dreifuss muscular dystrophy. because emerin has diverse roles in nuclear mechanics, cytoskeletal organization, and gene expression, it has been difficult to elucidate its contribution to nuclear structure and disease pathology. in this study, we investigated emerin's impact on nuclei assembled in xenopus laevis egg extract, a simplified biochemical system that lacks potentially confounding cellular factors and activities. notably ...201830332321
early redox activities modulate xenopus tail regeneration.redox state sustained by reactive oxygen species (ros) is crucial for regeneration; however, the interplay between oxygen (o2), ros and hypoxia-inducible factors (hif) remains elusive. here we observe, using an optic-based probe (optrode), an elevated and steady o2 influx immediately upon amputation. the spatiotemporal o2 influx profile correlates with the regeneration of xenopus laevis tadpole tails. inhibition of ros production but not ros scavenging decreases o2 influx. inhibition of hif-1α i ...201830327466
expression of trpv channels during xenopus laevis embryogenesis.transient receptor potential (trp) cation channel genes code for an extensive family of conserved proteins responsible for a variety of physiological processes, including sensory perception, ion homeostasis, and chemical signal transduction. the trp superfamily consists of seven subgroups, one of which is the transient receptor potential vanilloid (trpv) channel family. while trpv channels are relatively well studied in adult vertebrate organisms given their role in functions such as nociception ...201830326274
transcriptome analysis of xenopus orofacial tissues deficient in retinoic acid receptor function.development of the face and mouth is orchestrated by a large number of transcription factors, signaling pathways and epigenetic regulators. while we know many of these regulators, our understanding of how they interact with each other and implement changes in gene expression during orofacial development is still in its infancy. therefore, this study focuses on uncovering potential cooperation between transcriptional regulators and one important signaling pathway, retinoic acid, during developmen ...201830390632
flow cytometric analysis of xenopus laevis and x. tropicalis blood cells using acridine orange.automated blood cell counters can distinguish cells based on their size and the presence or absence of a nucleus. however, most vertebrates have nucleated blood cells that cannot be counted automatically. we established an alternative automatic method for counting peripheral blood cells by staining cells with the fluorescent dye acridine orange (ao) and analysing cell populations using flow cytometry (fcm). as promising new animal models, we chose xenopus laevis and three inbred strains of x. tr ...201830390005
size-dependent functional response of xenopus laevis feeding on mosquito larvae.predators can play an important role in regulating prey abundance and diversity, determining food web structure and function, and contributing to important ecosystem services, including the regulation of agricultural pests and disease vectors. thus, the ability to predict predator impact on prey is an important goal in ecology. often, predators of the same species are assumed to be functionally equivalent, despite considerable individual variation in predator traits known to be important for sha ...201830386704
trypanosoma brucei aquaglyceroporins mediate the transport of metabolic end-products: methylglyoxal, d-lactate, l-lactate and acetate.bloodstream forms of trypanosoma (t.) brucei, the causative agent of african sleeping sickness, possess a highly active glycolysis, which generates as main end-products: pyruvate under aerobic conditions, and pyruvate and glycerol under anaerobic conditions. to secrete them into the extracellular milieu, the parasites have at least two main specific membrane proteins, the pyruvate transporter and the aquaglyceroporins however, there are several other minor products from the glycolysis that must ...201830409521
brief local application of progesterone via a wearable bioreactor induces long-term regenerative response in adult xenopus hindlimb.the induction of limb repair in adult vertebrates is a pressing, unsolved problem. here, we characterize the effects of an integrated device that delivers drugs to severed hindlimbs of adult xenopus laevis, which normally regenerate cartilaginous spikes after amputation. a wearable bioreactor containing a silk protein-based hydrogel that delivered progesterone to the wound site immediately after hindlimb amputation for only 24 hr induced the regeneration of paddle-like structures in adult frogs. ...201830404012
atlht1 transporter can facilitate the uptake and translocation of a glycinergic-chlorantraniliprole conjugate in arabidopsis thaliana.understanding of the transporters involved in the uptake and translocation of agrochemicals in plants could provide an opportunity to guide pesticide to the site of insect feeding. the product of arabidopsis thaliana gene atlht1 makes a major contribution to the uptake into the roots of free amino acids and some of their derivatives. here, a chlorantraniliprole-glycine conjugate (cap-gly-1) was tested for its affinity to atlht1 both in planta and in vitro. seedlings deficient in atlht1 exhibited ...201830403859
cellspecks: a software for automated detection and analysis of calcium channels in live cells.to couple the fidelity of patch-clamp recording with a more high-throughput screening capability, we pioneered a, to our knowledge, novel approach to single-channel recording that we named "optical patch clamp." by using highly sensitive fluorescent ca2+ indicator dyes in conjunction with total internal fluorescence microscopy techniques, we monitor ca2+ flux through individual ca2+-permeable channels. this approach provides information about channel gating analogous to patch-clamp recording at ...201830447989
automating event-detection of brain neuron synaptic activity and action potential firing in vivo using a random-access multiphoton laser scanning microscope for real-time analysis.determining how a neuron computes requires an understanding of the complex spatiotemporal relationship between its input (e.g. synaptic input as a result of external stimuli) and action potential output. recent advances in in vivo, laser-scanning multiphoton technology, known as random-access microscopy (ram), can capture this relationship by imaging fluorescent light, emitted from calcium-sensitive biosensors responding to synaptic and action potential firing in a neuron's full dendritic arbor ...201830440280
expression of hyaluronan synthases upregulated by thyroid hormone is involved in intestinal stem cell development during xenopus laevis metamorphosis.during amphibian intestinal remodeling, thyroid hormone (th) induces adult stem cells, which newly generate the absorptive epithelium analogous to the mammalian one. we have previously shown that hyaluronan (ha) is newly synthesized and plays an essential role in the development of the stem cells via its major receptor cd44 in the xenopus laevis intestine. we here focused on ha synthase (has) and examined how the expression of has family genes is regulated during natural and th-induced metamorph ...201830430240
novel findings on the impact of chytridiomycosis on the cardiac function of anurans: sensitive vs. tolerant species.understanding of the physiological effects of chytridiomycosis is crucial to worldwide amphibian conservation. therefore, we analyzed the cardiac function of two anuran species (xenopus laevis and physalaemus albonotatus) with different susceptibilities to infection by the causative agent of chytridiomycosis, batrachochytrium dendrobatidis (hereafter bd).201830425891
a taxonomically and geographically constrained information base limits non-native reptile and amphibian risk assessment: a systematic review.for many taxa, new records of non-native introductions globally occur at a near exponential rate. we undertook a systematic review of peer-reviewed publications on non-native herpetofauna, to assess the information base available for assessing risks of future invasions, resulting in 836 relevant papers. the taxonomic and geographic scope of the literature was also compared to a published database of all known invasions globally. we found 1,116 species of herpetofauna, 95% of which were present i ...201830425887
development of an acute method to deliver transgenes into the brains of adult xenopus laevis.the central vocal pathway of the african clawed frog, xenopus laevis, is a powerful vertebrate model to understand mechanisms underlying central pattern generation. however, fast and efficient methods of introducing exogenous genes into the neurons of adult x. laevis are currently not available. here, we systematically tested methods of transgene delivery into adult x. laevis neurons. although successfully used for tadpole neurons for over a decade, electroporation was not efficient in transfect ...201830416430
the effect of an environmentally relevant phthalate mixture on primordial germ cells of xenopus laevis embryos. 201832550375
effects of quinine, quinidine and chloroquine on human muscle nicotinic acetylcholine receptors.the genus cinchona is known for a range of alkaloids, such as quinine, quinidine, cinchonine, and cinchonidine. cinchona bark has been used as an antimalarial agent for more than 400 years. quinine was first isolated in 1820 and is still acknowledged in the therapy of chloroquine-resistant falciparum malaria; in lower dosage quinine has been used as treatment for leg cramps since the 1940s. here we report the effects of the quinoline derivatives quinine, quinidine, and chloroquine on human adult ...201830515099
auditory perception exhibits sexual dimorphism and left telencephalic dominance in xenopus laevis.sex differences in both vocalization and auditory processing have been commonly found in vocal animals, although the underlying neural mechanisms associated with sexual dimorphism of auditory processing are not well understood. in this study we investigated whether auditory perception exhibits sexual dimorphism in xenopus laevis to do this we measured event-related potentials (erps) evoked by white noise (wn) and conspecific calls in the telencephalon, diencephalon and mesencephalon respectively ...201830509903
control of xenopus tadpole locomotion via selective expression of ih in excitatory interneurons.locomotion relies on the coordinated activity of rhythmic neurons in the hindbrain and spinal cord and depends critically on the intrinsic properties of excitatory interneurons. therefore, understanding how ion channels sculpt the properties of these interneurons, and the consequences for circuit function and behavior, is an important task. the hyperpolarization-activated cation current, ih, is known to play important roles in shaping neuronal properties and for rhythm generation in many neurona ...201830503615
genomic takeover by transposable elements in the strawberry poison frog.we sequenced the genome of the strawberry poison frog, oophaga pumilio, at a depth of 127.5× using variable insert size libraries. the total genome size is estimated to be 6.76 gb, of which 4.76 gb are from high copy number repetitive elements with low differentiation across copies. these repeats encompass dna transposons, rna transposons, and ltr retrotransposons, including at least 0.4 and 1.0 gb of mariner/tc1 and gypsy elements, respectively. expression data indicate high levels of gypsy and ...201830517748
modeling underwater hearing and sound localization in the frog xenopus laevis.animals that are small compared to sound wavelengths face the challenge of localizing a sound source since the main cues to sound direction-interaural time differences (itd) and interaural level differences (ild)-both depend on size. remarkably, the majority of terrestrial vertebrates possess internally coupled ears (ice) with an air-filled cavity connecting the two eardrums and producing an inherently directional middle-ear system. underwater, longer wavelengths and faster sound-speed reduce bo ...201830522324
silurana chromosomal evolution: a new piece to the puzzle.the african clawed frogs of the subgenus silurana comprise both diploid and tetraploid species. the root of the polyploidization event leading to the extant xenopus calcaratus, x. mellotropicalis, and x. epitropicalis is not fully understood so far. in x. mellotropicalis, we previously proposed 2 evolutionary scenarios encompassing complete (scenario a) or incomplete (scenario b) translocation of a heterochromatic block from chromosome 9 to 2 in a diploid ancestor. to resolve this puzzle, we per ...201830537723
the interplay between voluntary food intake, dietary carbohydrate-lipid ratio and nutrient metabolism in an amphibian, (xenopus laevis).digestion of food and metabolism of frogs are little studied at the moment, and such processes could be very particular in the case of amphibians, given their ectothermic and carnivorous nature which may lead them to use nutrients through specific biochemical pathways. in the present study, 24 adult xenopus laevis (six replicates with two frogs per treatment) were randomly assigned to two diets with different carbohydrate:fat ratio (4.5:1 and 2.1:1), changing the dietary glucogenic and lipogenic ...201830532132
xenopus hybrids provide insight into cell and organism size control.determining how size is controlled is a fundamental question in biology that is poorly understood at the organismal, cellular, and subcellular levels. the xenopus species, x. laevis and x. tropicalis differ in size at all three of these levels. despite these differences, fertilization of x. laevis eggs with x. tropicalis sperm gives rise to viable hybrid animals that are intermediate in size. we observed that although hybrid and x. laevis embryogenesis initiates from the same sized zygote and pr ...201830564147
alteration of the retinoid acid-cbp signaling pathway in neural crest induction contributes to enteric nervous system disorder.hirschsprung disease (hscr) and/or hypoganglionosis are common pediatric disorders that arise from developmental deficiencies of enteric neural crest cells (enccs). retinoid acid (ra) signaling has been shown to affect neural crest (nc) development. however, the mechanisms underlying ra deficiency-induced hscr or hypoganglionosis are not well-defined. in this report, we found that in hscr patient bowels, the ra nuclear receptor rarα and its interacting coregulator creb-binding protein (cbp) were ...201830560112
time-lapse imaging of cell death in cell culture and whole living organisms using turn-on deep-red fluorescent probes.cell death is a central process in developmental biology and also an important indicator of disease status and treatment efficacy. two related fluorescent probes are described that are molecular conjugates of one or two zinc dipicolylamine (zndpa) coordination complexes with an appended solvatochromic benzothiazolium squaraine dye. the probes were designed to target the anionic phospholipid, phosphatidylserine (ps), that is exposed on the surface of dead and dying cells. a series of spectrometri ...201830858977
ventx1.1 as a direct repressor of early neural gene zic3 in xenopus laevis.from xenopus embryo studies, the bmp4/smad1-targeted gene circuit is a key signaling pathway for specifying the cell fate between the ectoderm and neuro-ectoderm as well as the ventral and dorsal mesoderm. in this context, several bmp4/smad1 target transcriptional factors have been identified as repressors of the neuro-ectoderm. however, none of these direct target transcription factors in this pathway, including gata1b, msx1 and ventx1.1 have yet been proven as direct repressors of early neuro- ...201830590909
development of a rapid functional assay that predicts glut1 disease severity.to examine the genotype to phenotype connection in glucose transporter type 1 (glut1) deficiency and whether a simple functional assay can predict disease outcome from genetic sequence alone.201830588498
effects of copper on the early development of xenopus laevis: the case of cuso4 and bordeaux mixture solutions. 201830701063
combined effects of mutations in loop c and the loop d-e-g triangle on neonicotinoid interactions with drosophila dα1/chicken β2 hybrid nachrs.neonicotinoid insecticides interact with the orthosteric sites of nicotinic acetylcholine receptors (nachrs) formed at the interfaces of (a) two adjacent α subunits and (b) α and non-α subunits. however, little is known of the detailed contributions of these two orthosteric sites to neonicotinoid actions. we therefore applied voltage-clamp electrophysiology to the dα1/chicken β2 hybrid nachr expressed in xenopus laevis oocytes to explore the agonist actions of imidacloprid and thiacloprid on wil ...201830704712
the publications of embryologist lev v. beloussov.a list of papers and books of the late lev v. beloussov was compiled and is available in word and endnote supplements. the breadth of his work is briefly described.201830321582
bapx1 is required for jaw joint development in amphibians.the acquisition of a movable jaw and a jaw joint are key events in gnathostome evolution. jaws are derived from the neural crest derived pharyngeal skeleton and the transition from jawless to jawed vertebrates consists of major morphological changes, which must have a genetic foundation. recent studies on the effects of bapx1 knockdown in fish and chicken indicate that bapx1 has acquired such a role in primary jaw joint development during vertebrate evolution, but evidence from amphibians is mis ...201830168254
investigation of non-cb1, non-cb2 win55212-2-sensitive g-protein-coupled receptors in the brains of mammals, birds, and amphibians.previous studies have found non-cb1 non-cb2 g-protein-coupled receptors in rodents that are activated by the aminoalkylindole cannabinoid agonist win55212-2. this work obtained evidence for the presence or absence of similar receptors in the brains of other mammals, birds and amphibians.201830376752
cardiovascular pharmacology of k2p17.1 (task-4, talk-2) two-pore-domain k+ channels.k2p17.1 (task-4, talk-2) potassium channels are expressed in the heart and represent potential targets for pharmacological management of atrial and ventricular arrhythmias. reduced k2p17.1 expression was found in atria and ventricles of heart failure (hf) patients. modulation of k2p17.1 currents by antiarrhythmic compounds has not been comprehensively studied to date. the objective of this study was to investigate acute effects of clinically relevant antiarrhythmic drugs on human k2p17.1 channel ...201830008082
i spy with my little eye: a simple behavioral assay to test color sensitivity on digital displays.passive and interactive virtual reality (vr) environments are becoming increasingly popular in the field of behavioral neuroscience. while the technique was originally developed for human observers, corresponding applications have been adopted for the research of visual-driven behavior and neural circuits in animals. rgb color reproduction using red, green and blue primary color pixels is generally calibrated for humans, questioning if the distinct parameters are also readily transferable to oth ...201830127095
biological concerns on the selection of animal models for teratogenic testing.during pregnancy fetus can be exposed to a variety of chemicals which may induce abortion and malformations. due to the amounts of new substances coming into the market every year, a high demand for a rapid, reliable, and cost-effective method to detect potential toxicity is necessary. different species have been used as animal models for teratogen screening, most of them sharing similar development processes with humans. however, the application of embryology knowledge to teratology is hampered ...201829896687
transgenic xenopus laevis line for in vivo labeling of nephrons within the kidney.xenopus laevis embryos are an established model for studying kidney development. the nephron structure and genetic pathways that regulate nephrogenesis are conserved between xenopus and humans, allowing for the study of human disease-causing genes. xenopus embryos are also amenable to large-scale screening, but studies of kidney disease-related genes have been impeded because assessment of kidney development has largely been limited to examining fixed embryos. to overcome this problem, we have g ...201829642376
pharmacological profile of vestibular inhibitory inputs to superior oblique motoneurons.vestibulo-ocular reflexes (vor) are mediated by three-neuronal brainstem pathways that transform semicircular canal and otolith sensory signals into motor commands for the contraction of spatially specific sets of eye muscles. the vestibular excitation and inhibition of extraocular motoneurons underlying this reflex is reciprocally organized and allows coordinated activation of particular eye muscles and concurrent relaxation of their antagonistic counterparts. here, we demonstrate in isolated p ...201829556714
trrap is a central regulator of human multiciliated cell formation.the multiciliated cell (mcc) is an evolutionarily conserved cell type, which in vertebrates functions to promote directional fluid flow across epithelial tissues. in the conducting airway, mccs are generated by basal stem/progenitor cells and act in concert with secretory cells to perform mucociliary clearance to expel pathogens from the lung. studies in multiple systems, includingxenopus laevisepidermis, murine trachea, and zebrafish kidney, have uncovered a transcriptional network that regulat ...201829588376
embryonic lethality is not sufficient to explain hourglass-like conservation of vertebrate embryos.understanding the general trends in developmental changes during animal evolution, which are often associated with morphological diversification, has long been a central issue in evolutionary developmental biology. recent comparative transcriptomic studies revealed that gene expression profiles of mid-embryonic period tend to be more evolutionarily conserved than those in earlier or later periods. while the hourglass-like divergence of developmental processes has been demonstrated in a variety o ...201829568479
characterization of pax3 and sox10 transgenic xenopus laevis embryos as tools to study neural crest development.the neural crest is a multipotent population of cells that originates a variety of cell types. many animal models are used to study neural crest induction, migration and differentiation, with amphibians and birds being the most widely used systems. a major technological advance to study neural crest development in mouse, chick and zebrafish has been the generation of transgenic animals in which neural crest specific enhancers/promoters drive the expression of either fluorescent proteins for use ...201829522707
molecular and functional characterization of the gulf toadfish serotonin transporter (sert; slc6a4).the serotonin transporter (sert) functions in the uptake of the neurotransmitter serotonin (5-ht) from the extracellular milieu and is the molecular target of the selective serotonin reuptake inhibitors (ssris), a common group of antidepressants. the current study comprehensively assesses the sequence, tissue distribution, transport kinetics, and physiological function of a teleost sert. the 2,022-bp toadfish sert sequence encodes a protein of 673 amino acids, which shows 83% similarity to zebra ...201829487159
fam60al as a novel factor involved in reprogramming of somatic cell nuclear transfer in zebrafish (danio rerio).the main reason for abnormal development of cloned animals or embryos, and inefficient animal cloning, is a poor understanding of the reprogramming mechanism. to better comprehend reprogramming and subsequent generation of pluripotent stem cells, we must investigate factors related to reprogramming of somatic cells as nuclear donors. as we know,fam60al(family with sequence similarity 60, member a, like) is a coding gene only found in zebrafish and frog (xenopus laevis) among vertebrates. however ...201829483827
chemical screening using cell-freexenopusegg extract.most drug screening methods use purified proteins, cultured cells, and/or small model organisms such asxenopus, zebrafish, flies, or nematodes. these systems have proven successes in drug discovery, but they also have weaknesses. although purified cellular components allow for identification of compounds with activity against specific targets, such systems lack the complex biological interactions present in cellular and organismal screens. in vivo systems overcome these weaknesses, but the lack ...201829475996
expression of the adhesion g protein-coupled receptor a2 (adgra2) during xenopus laevis development.the adhesion g protein-coupled receptor a2 (adgra2) is a seven transmembrane receptor that has been described to be a regulator for angiogenesis in mice. furthermore, the zebrafish ouchless mutant is unable to develop dorsal root ganglia through a disrupted trafficking of adgra2. besides rna sequencing data, nothing is reported about adgra2 in the south african crawled frog xenopus laevis. in this study, we investigated for the first time the spatio-temporal expression of adgra2 during early xen ...201829462671
physiological effects of kdm5c on neural crest migration and eye formation during vertebrate development.lysine-specific histone demethylase 5c (kdm5c) belongs to the jumonji family of demethylases and is specific for the di- and tri-demethylation of lysine 4 residues on histone 3 (h3k4 me2/3). kdm5c is expressed in the brain and skeletal muscles of humans and is associated with various biologically significant processes. kdm5c is known to be associated with x-linked mental retardation and is also involved in the development of cancer. however, the developmental significance of kdm5c has not been e ...201830522514
ivermectin promotes peripheral nerve regeneration during wound healing.peripheral nerves have the capacity to regenerate due to the presence of neuroprotective glia of the peripheral nervous system, schwann cells. upon peripheral nerve injury, schwann cells create a permissive microenvironment for neuronal regrowth by taking up cytotoxic glutamate and secreting neurotrophic signaling molecules. impaired peripheral nerve repair is often caused by a defective schwann cell response after injury, and there is a critical need to develop new strategies to enhance nerve r ...201830411007
divergent axial morphogenesis and earlyshhexpression in vertebrate prospective floor plate.the notochord has organizer properties and is required for floor plate induction and dorsoventral patterning of the neural tube. this activity has been attributed to sonic hedgehog (shh) signaling, which originates in the notochord, forms a gradient, and autoinducesshhexpression in the floor plate. however, reported data are inconsistent and the spatiotemporal development of the relevantshhexpression domains has not been studied in detail. we therefore studied the expression dynamics ofshhin rab ...201829423139
cloning and spatiotemporal expression of xenopus laevis apolipoprotein ci.apolipoprotein ci (apoci) belongs to the apolipoprotein superfamily, members of which are involved in lipid transport, uptake and homeostasis. excessive apoci has been implicated in atherosclerosis and alzheimer's disease in humans. in this study we report the isolation of xenopus laevis apoci and describe the expression pattern of this gene during early development, using reverse transcription polymerase chain reaction and whole mount in situ hybridization. xenopus apoci is enriched in the dors ...201829346450
effects of amphibian phylogeny, climate and human impact on the occurrence of the amphibian-killing chytrid fungus.chytridiomycosis, due to the fungus batrachochytrium dendrobatidis (bd), has been associated with the alarming decline and extinction crisis of amphibians worldwide. because conservation programs are implemented locally, it is essential to understand how the complex interactions among host species, climate and human activities contribute to bd occurrence at regional scales. using weighted phylogenetic regressions and model selection, we investigated geographic patterns of bd occurrence along a l ...201728055125
an inducible amphipathic helix within the intrinsically disordered c-terminus is not required for protein biosynthesis, trafficking, or garp2 interaction, but can participate in membrane curvature generation by peripherin-2/rds.peripherin-2/rds is required for biogenesis of vertebrate photoreceptor outer segment organelles. its localization at the high curvature rim domains of outer segment disk membranes suggests that it may act to shape these structures; however, the molecular function of this protein is not yet resolved. here, we apply biochemical, biophysical, and imaging techniques, to elucidate the role(s) played by the protein's intrinsically disordered c-terminal domain, and an incipient amphipathic α-helix con ...201728325841
immune roles of amphibian (xenopus laevis) tadpole granulocytes during frog virus 3 ranavirus infections.infections by frog virus 3 (fv3) and other ranaviruses (rvs) are contributing to the amphibian declines, while the mechanisms controlling anuran tadpole susceptibility and adult frog resistance to rvs, including the roles of polymorphonuclear granulocytes (pmns) during anti-fv3 responses, remain largely unknown. since amphibian kidneys represent an important fv3 target, the inability of amphibian (xenopus laevis) tadpoles to mount effective kidney inflammatory responses to fv3 is thought to cont ...201728238879
amphibian (xenopus laevis) tadpoles and adult frogs mount distinct interferon responses to the frog virus 3 ranavirus.infections of amphibians by frog virus 3 (fv3) and other ranavirus genus members are significantly contributing to the amphibian declines, yet much remains unknown regarding amphibian antiviral immunity. notably, amphibians represent an important step in the evolution of antiviral interferon (ifn) cytokines as they are amongst the first vertebrates to possess both type i and type iii ifns. accordingly, we examined the roles of type i and iii ifns in the skin of fv3-challenged amphibian xenopus l ...201728081430
long term effects of carbaryl exposure on antiviral immune responses in xenopus laevis.water pollutants associated with agriculture may contribute to the increased prevalence of infectious diseases caused by ranaviruses. we have established the amphibian xenopus laevis and the ranavirus frog virus 3 (fv3) as a reliable experimental platform for evaluating the effects of common waterborne pollutants, such as the insecticide carbaryl. following 3 weeks of exposure to 10 ppb carbaryl, x. laevis tadpoles exhibited a marked increase in mortality and accelerated development. exposure at ...201727988452
hepatitis e virus orf3 is a functional ion channel required for release of infectious particles.hepatitis e virus (hev) is the leading cause of enterically transmitted viral hepatitis globally. of hev's three orfs, the function of orf3 has remained elusive. here, we demonstrate that via homophilic interactions orf3 forms multimeric complexes associated with intracellular endoplasmic reticulum (er)-derived membranes. hev orf3 shares several structural features with class i viroporins, and the function of hev orf3 can be maintained by replacing it with the well-characterized viroporin influe ...201728096411
the malaria parasite's lactate transporter pffnt is the target of antiplasmodial compounds identified in whole cell phenotypic screens.in this study the 'malaria box' chemical library comprising 400 compounds with antiplasmodial activity was screened for compounds that perturb the internal ph of the malaria parasite, plasmodium falciparum. fifteen compounds induced an acidification of the parasite cytosol. two of these did so by inhibiting the parasite's formate nitrite transporter (pffnt), which mediates the h+-coupled efflux from the parasite of lactate generated by glycolysis. both compounds were shown to inhibit lactate tra ...201728178359
aquaglyceroporins are the entry pathway of boric acid in trypanosoma brucei.the boron element possesses a range of different effects on living beings. it is essential to beneficial at low concentrations, but toxic at excessive concentrations. recently, some boron-based compounds have been identified as promising molecules against trypanosoma brucei, the causative agent of sleeping sickness. however, until now, the boron metabolism and its access route into the parasite remained elusive. the present study addressed the permeability of t. brucei aquaglyceroporins (tbaqps) ...201728087364
functional characterisation and cell specificity of bvsut1, the transporter that loads sucrose into the phloem of sugar beet (beta vulgaris l.) source leaves.sugar beet (beta vulgaris l.) is one of the most important sugar-producing plants worldwide and provides about one third of the sugar consumed by humans. here we report on molecular characterisation of the bvsut1 gene and on the functional characterisation of the encoded transporter. in contrast to the recently identified tonoplast-localised sucrose transporter bvtst2.1 from sugar beet taproots, which evolved within the monosaccharide transporter (mst) superfamily, bvsut1 represents a classical ...201728075052
sucrose transporter localization and function in phloem unloading in developing stems.how sucrose transporters (suts) regulate phloem unloading in monocot stems is poorly understood and particularly so for species storing high suc concentrations. to this end, sorghum bicolor suts sbsut1 and sbsut5 were characterized by determining their transport properties heterologously expressed in yeast or xenopus laevis oocytes, and their in planta cellular and subcellular localization. the plasma membrane-localized sbsut1 and sbsut5 exhibited a strong selectivity for suc and high suc affini ...201727986867
h(+)-dependent inorganic phosphate uptake in trypanosoma brucei is influenced by myo-inositol transporter.trypanosoma brucei is an extracellular protozoan parasite that causes human african trypanosomiasis or "sleeping sickness". during the different phases of its life cycle, t. brucei depends on exogenous inorganic phosphate (pi), but little is known about the transport of pi in this organism. in the present study, we showed that the transport of (32)pi across the plasma membrane follows michaelis-menten kinetics and is modulated by ph variation, with higher activity at acidic ph. bloodstream forms ...201728185085
two spatially and temporally distinct ca(2+) signals convey arabidopsis thaliana responses to k(+) deficiency.in plants, potassium (k(+) ) homeostasis is tightly regulated and established against a concentration gradient to the environment. despite the identification of ca(2+) -regulated kinases as modulators of k(+) channels, the immediate signaling and adaptation mechanisms of plants to low-k(+) conditions are only partially understood. to assess the occurrence and role of ca(2+) signals in arabidopsis thaliana roots, we employed ratiometric analyses of ca(2+) dynamics in plants expressing the ca(2+) ...201727579668
polar localization of the nip5;1 boric acid channel is maintained by endocytosis and facilitates boron transport in arabidopsis roots.boron uptake in arabidopsis thaliana is mediated by nodulin 26-like intrinsic protein (nip)5;1, a boric acid channel that is located preferentially on the soil side of the plasma membrane in root cells. however, the mechanism underlying this polar localization is poorly understood. here, we show that the polar localization of nip5;1 in epidermal and endodermal root cells is mediated by the phosphorylation of thr residues in the conserved tpg (thrprogly) repeat in the n-terminal region of nip5;1. ...201728341806
models of amphibian myogenesis - the case of bombina variegata.several different models of myogenesis describing early stages of amphibian paraxial myotomal myogenesis are known. myoblasts of xenopus laevis and hymenochirus boettgeri change their position from perpendicular to parallel, in relation to axial organs, and differentiate into mononucleate myotubes. in bombina variegate the myotomal myoblasts change their shape from round to elongate and then differentiate into mononuclear, morphologically mature myotubes. in pelobates fuscus and triturus vulgari ...201728287243
cloning and expression analysis of zygote arrest 1 (zar1) in new zealand white rabbits.zygote arrest 1 (zar1) is an oocyte-specific maternal-effect gene. previous studies indicate that zar1 plays important role in early embryo development, but little is known about its function in rabbit. the objectives of this study were to clone the new zealand white rabbit zar1 gene and to investigate its expression in various organs in groups of animals with different reproductive traits.we obtained a 709-bp zar1 cdna fragment consisting of an 8-bp exon 1, 161-bp exon 2, 75-bp exon 3, 271-bp e ...201728360383
targeting functional noncoding rnas.noncoding rnas have essential biochemical functions in different areas of cellular metabolism, including protein synthesis, rna splicing, protein secretion, and dna replication. we have successfully used morpholino antisense oligonucleotides for the functional inactivation of small noncoding rnas required for dna replication (y rnas in vertebrates and stem-bulge rnas in nematodes). here we discuss specific issues of targeting functional noncoding rnas for inactivation by morpholino antisense oli ...201728364241
isolation and functional characterization of cslsi1, a silicon transporter gene in cucumis sativus.cucumber (cucumis sativus) is a widely grown cucurbitaceous vegetable that exhibits a relatively high capacity for silicon (si) accumulation, but the molecular mechanism for silicon uptake remains to be clarified. here we isolated and characterized cslsi1, a gene encoding a silicon transporter in cucumber (cv. mch-4). cslsi1 shares 55.70 and 90.63% homology with the lsi1s of a monocot and dicot, rice (oryza sativa) and pumpkin (cucurbita moschata), respectively. cslsi1 was predominantly expresse ...201727701737
a staging table of post-ovipositional development for the south american collared lizard tropidurus torquatus (squamata: tropiduridae).the mouse, chicken, african clawed frog, and zebrafish are considered ¨model organisms¨ due to their extensive embryological and genetic characterization. however, they are far from representative of known diversity, impairing phylogenetic analyses of developmental patterns. since squamates have historically received limited attention in developmental studies, we here describe the developmental sequence for tropidurus torquatus, and provide the first post-ovipositional developmental series for t ...201727741560
first parasitological study of the african clawed frog (xenopus laevis, amphibia) in chile.introduced species can arrive into new territories with parasites; however, these species are expected to face lower parasite richness than in their original regions. both introduced hosts and parasites can affect native fauna. since their release into the wild in chile following laboratory use, xenopus laevis daudin, 1802 has widely spread throughout central chile. the only pathogen described on the host is the fungus batrachochytrium dendrobatidis longcore, pessier, nichols, 1999; thus, this i ...201728746452
heterologous expression of panax ginseng pgtip1 confers enhanced salt tolerance of soybean cotyledon hairy roots, composite, and whole plants.the panax ginseng tip gene pgtip1 was previously demonstrated to have high water channel activity by its heterologous expression in xenopus laevis oocytes and in yeast; it also plays a significant role in growth of pgtip1-transgenic arabidopsis plants under favorable conditions and has enhanced tolerance toward salt and drought treatment. in this work, we first investigated the physiological effects of heterologous pgtip1 expression in soybean cotyledon hairy roots or composite plants mediated b ...201728769947
the xenopus tadpole: an in vivo model to screen drugs favoring remyelination.in multiple sclerosis, development of screening tools for remyelination-promoting molecules is timely.201728752787
functional characterization of an aquaporin from a microsporidium, nosema bombycis.microsporidia are a diverse group of eukaryotic organisms, capable of causing parasitic infections in both vertebrates and invertebrates. during the germination process, there is an increase in the osmotic pressure of microsporidian spores. as part of this study, we cloned a homologous aquaporin gene in nosema bombycis, and named it nosema bombycis aquaporin (nbaqp). sequence analysis revealed that the nbaqp contains an open reading frame with a length of 750 bp and encodes a polypeptide of 249 ...201728749993
iron is a substrate of the plasmodium falciparum chloroquine resistance transporter pfcrt in xenopus oocytes.the chloroquine resistance transporter of the human malaria parasite plasmodium falciparum, pfcrt, is an important determinant of resistance to several quinoline and quinoline-like antimalarial drugs. pfcrt also plays an essential role in the physiology of the parasite during development inside erythrocytes. however, the function of this transporter besides its role in drug resistance is still unclear. using electrophysiological and flux experiments conducted on pfcrtexpressing xenopus laevis oo ...201728768767
multi-omics analysis sheds light on the evolution and the intracellular lifestyle strategies of spotted fever group rickettsia spp.arthropod-borne rickettsia species are obligate intracellular bacteria which are pathogenic for humans. within this genus, rickettsia slovaca and rickettsia conorii cause frequent and potentially severe infections, whereas rickettsia raoultii and rickettsia massiliae cause rare and milder infections. all four species belong to spotted fever group (sfg) rickettsiae. however, r. slovaca and r. raoultii cause scalp eschar and neck lymphadenopathy (senlat) and are mainly associated with dermacentor ...201728775717
toxicity effects of functionalized quantum dots, gold and polystyrene nanoparticles on target aquatic biological models: a review.nano-based products are widespread in several sectors, including textiles, medical-products, cosmetics, paints and plastics. nanosafety and safe-by-design are driving nanoparticle (np) production and applications through np functionalization (@nps). indeed, @nps frequently present biological effects that differ from the parent material. this paper reviews the impact of quantum dots (qds), gold nanoparticles (aunps), and polystyrene-cored nps (psnps), evidencing the role of np functionalization i ...201728858240
molecular evolution of two distinct dmrt1 promoters for germ and somatic cells in vertebrate gonads.the transcription factor dmrt1 has important functions in two distinct processes, somatic-cell masculinization and germ-cell development in mammals. however, it is unknown whether the functions are conserved during evolution, and what mechanism underlies its expression in the two cell lineages. our analysis of the xenopus laevis and silurana tropicalis dmrt1 genes indicated the presence of two distinct promoters: one upstream of the noncoding first exon (ncex1), and one within the first intron. ...201727927791
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