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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
the effect of an environmentally relevant phthalate mixture on primordial germ cells of xenopus laevis embryos. 201832550375
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
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
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
thyroid hormone levels and temperature during development alter thermal tolerance and energetics of xenopus laevis larvae.environmental variation induced by natural and anthropogenic processes including climate change may threaten species by causing environmental stress. anuran larvae experiencing environmental stress may display altered thyroid hormone (th) status with potential implications for physiological traits. therefore, any capacity to adapt to environmental changes through plastic responses provides a key to determining species vulnerability to environmental variation. we investigated whether developmenta ...201830464840
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
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
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
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
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
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
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
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
functional analysis of a triplet deletion in the gene encoding the sodium glucose transporter 3, a potential risk factor for adhd.sodium-glucose transporters (sglt) belong to the solute carrier 5 family, which is characterized by sodium dependent transport of sugars and other solutes. in contrast, the human sglt3 (hsglt3) isoform, encoded by slc5a4, acts as a glucose sensor that does not transport sugar but induces membrane depolarization by na+ currents upon ligand binding. whole-exome sequencing (wes) of several extended pedigrees with high density of attention-deficit/hyperactivity disorder (adhd) identified a triplet a ...201830286162
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
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
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
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
ras-dva small gtpases lost during evolution of amniotes regulate regeneration in anamniotes.in contrast to amniotes (reptiles, birds and mammals), anamniotes (fishes and amphibians) can effectively regenerate body appendages such as fins, limbs and tails. why such a useful capability was progressively lost in amniotes remains unknown. as we have hypothesized recently, one of the reasons for this could be loss of some genes regulating the regeneration in evolution of amniotes. here, we demonstrate the validity of this hypothesis by showing that genes of small gtpases ras-dva1 and ras-dv ...201830158598
isolation and primary culture methods of adult and larval myogenic cells from xenopus laevis.during amphibian metamorphosis, larval-to-adult conversion of the myogenic system occurs and there are two distinct types of muscle stem cells; larval myogenic cells have a death-fate by apoptosis in the presence of thyroid hormone t3, and adult myogenic cells have a life-fate under the same conditions. here, we describe isolation and culture methods for adult and larval myogenic cells from the frog, xenopus laevis. both types of cultured myogenic cells undergo cell division and cell differentia ...201830151775
isolation and culture of amphibian (xenopus laevis) sub-capsular liver and bone marrow cells.the x. laevis sub-capsular liver is thought to be the principal hematopoietic site of xenopodinae species from early development and, in case of certain species, into adulthood. the xenopus bone marrow appears to be comprised of precursor cells committed to myeloid lineages, such as macrophage- and granulocyte-progenitor cells. with alarming increases in the contribution of pathogenic infections to the global amphibian declines, now more than ever a better understanding of the mechanisms control ...201830151774
x-fact: xenopus-fast clearing technique.accessibility and imaging of cell compartments in big specimens are crucial for cellular biological research but also a matter of contention. confocal imaging and tissue clearing on whole organs allow for 3d imaging of cellular structures after being subjected to in-toto immunohistochemistry. lately, the passive clarity technique (pact) has been adapted to clear and immunolabel large specimens or individual organs of several aquatic species. we recently demonstrated tissue clearing on one-week o ...201830151770
dye electroporation and imaging of calcium signaling in xenopus nervous system.electroporation is an efficient method of transferring charged macromolecules into living cells in order to study their morphology, function, and connectivity within neuronal networks. labeling cells with fluorophore-coupled macromolecules can be used to trace projections of whole neuronal ensembles, as well as the fine morphology of single cells. here, we present a protocol to visualize pre- and postsynaptic components of a sensory relay synapse in the brain, using the olfactory system of xenop ...201830151769
quantitative proteomics for xenopus embryos ii, data analysis.the oocytes, embryos, and cell-free lysates of the frog xenopus laevis have emerged as powerful models for quantitative proteomic experiments. in the accompanying paper (chapter 13) we describe how to prepare samples and acquire multiplexed proteomics spectra from those. as an illustrative example we use a 10-stage developmental time series from the egg to stage 35 (just before hatching). here, we outline how to convert the ~700,000 acquired mass spectra from this time series into protein expres ...201830151768
quantitative proteomics of xenopus embryos i, sample preparation.xenopus oocytes and embryos are model systems optimally suited for quantitative proteomics. this is due to the availability of large amount of protein material and the ease of physical manipulation. furthermore, facile in vitro fertilization provides superbly synchronized embryos for cell cycle and developmental stages. here, we detail protocols developed over the last few years for sample preparation of multiplexed proteomics with tmt-tags followed by quantitative mass spectrometry analysis usi ...201830151767
a simple knock-in system for xenopus via microhomology mediated end joining repair.following completion of the genome sequences of xenopus tropicalis and x. laevis, gene targeting techniques have become increasingly important for the further development of xenopus research in the life sciences. gene knockout using programmable nucleases, such as talen and crispr/cas9, has reached a level whereby we can readily and routinely perform loss-of-function analysis of genes of interest in these species. however, there is still room for improvement in gene knock-in techniques owing to ...201830151761
generation and care of xenopus laevis and xenopus tropicalis embryos.robust and efficient protocols for fertilization and early embryo care of xenopus laevis and xenopus tropicalis are essential for experimental success, as well as maintenance and propagation of precious animal stocks. the rapid growth of the national xenopus resource has required effective implementation and optimization of these protocols. here, we discuss the procedures used at the national xenopus resource, which we found helpful for generation and early upkeep of xenopus embryos and tadpoles ...201830151756
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
husbandry, general care, and transportation of xenopus laevis and xenopus tropicalis.maintenance of optimal conditions such as water parameters, diet, and feeding is essential to a healthy xenopus laevis and xenopus tropicalis colony and thus to the productivity of the lab. our prior husbandry experience as well as the rapid growth of the national xenopus resource has given us a unique insight into identifying and implementing these optimal parameters into our husbandry operations. here, we discuss our standard operating procedures that will be of use to both new and established ...201830151755
unusual light-reflecting pigment cells appear in the xenopus neural tube culture system in the presence of guanosine.isolation and culture of xenopus laevis neural tubes resulted in differentiation of melanophores and iridophores from neural crest cells; the differentiated melanophores and iridophores were then maintained in culture for more than 6 months. guanosine has been reported to promote reflecting platelet formation in melanin-producing pigment cells; however, the process of pigment organellogenesis is still unclear. in the present study, unusual light-reflecting pigment cells were observed upon additi ...201830309510
uroplakins play conserved roles in egg fertilization and acquired additional urothelial functions during mammalian divergence.uroplakin (up) tetraspanins and their associated proteins are major mammalian urothelial differentiation products that form unique two-dimensional crystals of 16-nm particles ("urothelial plaques") covering the apical urothelial surface. although uroplakins are highly expressed only in mammalian urothelium and are often referred to as being urothelium specific, they are also expressed in several mouse nonurothelial cell types in stomach, kidney, prostate, epididymis, testis/sperms, and ovary/ooc ...201830303751
retinal tissue preparation for high-resolution live imaging of photoreceptors expressing multiple transgenes.live imaging has become the favorite method in recent years to study the protein transport, localization and dynamics in live cells. protein transport is extremely essential for proper function of photoreceptors. aberration in the proper transport of proteins gives rise to the loss of photoreceptor and blindness. on the other hand, the ease of generation of transgenic xenopus laevis tadpoles and the advantage of high resolution live confocal imaging provide new insight into understanding protein ...201830302320
antibacterial and antibiofilm activity and mode of action of magainin 2 against drug-resistant acinetobacter baumannii.antimicrobial peptides (amps) are promising therapeutic agents for treating antibiotic-resistant bacterial infections. previous studies showed that magainin 2 (isolated from african clawed fogs xenopus laevis) has antimicrobial activity against gram-positive and gram-negative bacteria. the present study was conducted to investigate the antibacterial activity of magainin 2 against acinetobacter baumannii. magainin 2 showed excellent antibacterial activity against a. baumannii strains and high sta ...201830301180
evaluating iodide recycling inhibition as a novel molecular initiating event for thyroid axis disruption in amphibians.the enzyme iodotyrosine deiodinase (dehalogenase, iyd) catalyzes iodide recycling and promotes iodide retention in thyroid follicular cells. loss of function or chemical inhibition of iyd reduces available iodide for thyroid hormone synthesis, which leads to hormone insufficiency in tissues and subsequent negative developmental consequences. iyd activity is especially critical under conditions of lower dietary iodine and in low iodine environments. our objective was to evaluate the toxicological ...201830137636
kv12.1 channels are not sensitive to gqpcr-triggered activation of phospholipase cβ.kv12.1 k+ channels are expressed in several brain areas, but no physiological function could be attributed to these subunits so far. as genetically-modified animal models are not available, identification of native kv12.1 currents must rely on characterization of distinct channel properties. recently, it was shown in xenopus laevis oocytes that kv12.1 channels were modulated by membrane pi(4,5)p2. however, it is not known whether these channels are also sensitive to physiologically-relevant pi(4 ...201830136882
developmental dependence for functional eye regrowth in xenopus laevis. 201830136686
photocatalytic degradation of azo dye using core@shell nano-tio2 particles to reduce toxicity.clean and safe water is fundamental for human and environmental health. traditional remediation of textile dye-polluted water with chemical, physical, and biological processes has many disadvantages. due to this, nano-engineered materials are drawing more attention to this area. however, the widespread use of nano-particles for this purpose may lead to photocatalytic degradation of xenobiotics, while increasing the risk of nano-particle-induced ecotoxicity. therefore, we comparatively evaluated ...201830136182
cross-limb communication during xenopus hindlimb regenerative response: non-local bioelectric injury signals.regeneration of damaged body parts requires coordination of size, shape, location and orientation of tissue with the rest of the body. it is not currently known to what extent injury sites communicate with the remaining soma during repair, or what information may emanate from the injury site and reach other regions. we examined the bioelectric properties (resting potential gradients in the epidermis) of xenopus laevis froglets undergoing hindlimb amputation and observed that the contralateral (u ...201830126906
molecular characterization of wdr68 gene in embryonic development of xenopus laevis.wdr68, also known as dcaf7, is a wd40 repeated domain protein highly conserved in eukaryotic organisms in both plants and animals. this protein participates in numerous cellular processes and exerts its function through interaction with other proteins. in the present work, we isolated, sequenced and characterized cdna corresponding to the wdr68 gene in embryos of the amphibian xenopus laevis. syntenic analysis revealed high conservation of the genomic region containing the wdr68 locus in amniote ...201830125741
in vitro expression and functional characterization of npa motifs in aquaporins of nosema bombycis.nosema bombycis contains functional aquaporins (nbaqps), which are key targets for exploring the mechanism of n. bombycis infection; however, the regulation of these nbaqps remains unknown. the two highly conserved asparagine-proline-alanine sequences (npa motifs) play important roles in aqp biogenesis. as part of this study, we constructed a series of nbaqp mutants (nbaqp_npa1, nbaqp_npa2, and nbaqp_npa1,2) and expressed them in bmn cells. the results showed that mutations in either npa motif o ...201830105406
inward- and outward-facing homology modeling of human concentrative nucleoside transporter 3 (hcnt3) predicts an elevator-type transport mechanism.the human slc28 family of concentrative (na+-dependent) nucleoside transporters has three members, hcnt1, hcnt2 and hcnt3. previously, we have used heterologous expression in xenopus laevis oocytes in combination with an engineered cysteine-less hcnt3 protein hcnt3(c-) to undertake systematic substituted cysteine accessibility method (scam) analysis of the transporter using the membrane-impermeant thiol reactive reagent p-chloromercuribenzene sulfonate (pcmbs). a continuous sequence of more than ...201830096006
a sodium transporter hvhkt1;1 confers salt tolerance in barley via regulating tissue and cell ion homeostasis.our previous studies showed that high salt tolerance in tibetan wild barley accessions was associated with hvhkt1;1, a member of the high-affinity potassium transporter family. however, molecular mechanisms of hvhkt1;1 for salt tolerance and its roles in k+/na+ homeostasis remain to be elucidated. functional characterization of hvhkt1;1 was conducted in the present study. nacl-induced transcripts of hvhkt1;1 were significantly higher in the roots of tibetan wild barley xz16 relative to other gen ...201829917153
the rna-binding complex escrt-ii in xenopus laevis eggs recognizes purine-rich sequences through its subunit, vps25.rna-binding proteins (rbp) are critical regulators of gene expression. recent studies have uncovered hundreds of mrna-binding proteins that do not contain annotated rna-binding domains and have well-established roles in other cellular processes. investigation of these nonconventional rbps is critical for revealing novel rna-binding domains and may disclose connections between rna regulation and other aspects of cell biology. the endosomal sorting complex required for transport ii (escrt-ii) is a ...201829903915
transcriptome of xenopus andrei, an octoploid frog, during embryonic development.although polyploidy occurs throughout the fish and amphibian lineages, the xenopus genus exhibits a high incidence of polyploidy, with 25 out of the 26 known species being polyploid. however, transcriptomic information is currently available for only one of these species, the tetraploid xenopus laevis. xenopus andrei, an octoploid species within the xenopus genus, offers an opportunity for assessing a novel polyploid transcriptome during vertebrate development. rna-seq data was generated at nine ...201829900348
validation and bioinformatics analysis of differentially expressed circrnas involved in developing male xenopus laevis chronically exposed to atrazine.the data presented here are related to the research article titled "identification of circular rnas and their alterations involved in developing male xenopus laevis chronically exposed to atrazine" (sai et al., 2018) [1]. circular rnas (circrnas) are implicated in multiple developmental anomalies (bachmayr-heyda et al., 2015; li et al., 2015) [2], [3]. this report describes the differentially expressed circrnas involved in developing male xenopus laevis (x. laevis) chronically exposed to atrazin ...201829900306
regulation of nuclear factor of activated t cells (nfat) and downstream myogenic proteins during dehydration in the african clawed frog.xenopus laevis, otherwise known as the african clawed frog, undergoes natural dehydration of up to 30% of its total body water during the dry season in sub-saharan africa. to survive under these conditions, a variety of physiological and biochemical changes take place in x. laevis. we were interested in understanding the role that the calcineurin-nfat pathway plays during dehydration stress response in the skeletal muscles of x. laevis. immunoblotting was performed to characterize the protein le ...201829923155
semicircular canal influences on the developmental tuning of the translational vestibulo-ocular reflex.vestibulo-ocular reflexes (vors) rely on neuronal computations that transform vestibular sensory signals into spatio-temporally appropriate extraocular motor commands. the motoneuronal discharge for contractions of the superior oblique eye muscle during linear translation derives from a utricular epithelial sector that is spatially aligned with the pulling direction of this muscle. in xenopus laevis, the alignment is gradually achieved during larval development and requires motion-related semici ...201829922219
atrial fibrillation and heart failure-associated remodeling of two-pore-domain potassium (k2p) channels in murine disease models: focus on task-1.understanding molecular mechanisms involved in atrial tissue remodeling and arrhythmogenesis in atrial fibrillation (af) is essential for developing specific therapeutic approaches. two-pore-domain potassium (k2p) channels modulate cellular excitability, and task-1 (k2p3.1) currents were recently shown to alter atrial action potential duration in af and heart failure (hf). finding animal models of af that closely resemble pathophysiological alterations in human is a challenging task. this study ...201829881975
pou3f transcription factor expression during embryonic development highlights distinct pou3f3 and pou3f4 localization in the xenopus laevis kidney.the pou (pit-oct-unc) genes encode a large transcription factor family comprising 6 classes (pou1f to pou6f ) involved in many developmental processes, such as cell commitment and differentiation. the pou3f class contains four members (pou3f1, pou3f2, pou3f3, pou3f4) characterized by expression in ectodermal tissue derivatives, such as nervous system and otic vesicle, during mammalian development. in order to obtain insights into the potential conservation of this class of transcription factors ...201829877572
lrpap1 as a specific marker of proximal pronephric kidney tubuli in xenopus laevis embryos.lrpap1, also known as receptor associated protein (rap) is a small protein of 40 kda associated with six of the seven members of the evolutionary conserved family of ldl receptors. numerous studies showed that lrpap1 has a dual function, initially as a chaperone insuring proper formation of intermolecular disulfide bonds during biogenesis of low density lipoprotein (ldl) receptors and later as an escort protein during trafficking through the endoplasmic reticulum and the early golgi compartment, ...201829877571
genome-wide transcriptomics analysis of genes regulated by gata4, 5 and 6 during cardiomyogenesis in xenopus laevis.the transcription factors gata4, gata5 and gata6 play important roles in heart muscle differentiation. the data presented in this article are related to the research article entitled "genome-wide transcriptomics analysis identifies sox7 and sox18 as specifically regulated by gata4 in cardiomyogenesis" (afouda et al., 2017) [1]. the present study identifies genes regulated by these individual cardiogenic gata factors using genome-wide transcriptomics analysis. we have presented genes that are spe ...201829876429
ligand binding and activation properties of the purified bacterial cyclic nucleotide-gated channel sthk.cyclic nucleotide-modulated ion channels play several essential physiological roles. they are involved in signal transduction in photoreceptors and olfactory sensory neurons as well as pacemaking activity in the heart and brain. investigations of the molecular mechanism of their actions, including structural and electrophysiological characterization, are restricted by the availability of stable, purified protein obtained from accessible systems. here, we establish that sthk, a cyclic nucleotide- ...201829752414
retraction of rod-like mitochondria during microtubule-dependent transport.molecular motors play relevant roles on the regulation of mitochondria size and shape, essential properties for the cell homeostasis. in this work, we tracked single rod-shaped mitochondria with nanometer precision to explore the performance of microtubule motor teams during processive anterograde and retrograde transport. we analyzed simultaneously the organelle size and verified that mitochondria retracted during retrograde transport with their leading tip moving slower in comparison with the ...201829752335
determination of metals and pharmaceutical compounds released in hospital wastewater from toluca, mexico, and evaluation of their toxic impact.due to the activities inherent to medical care units, the hospital effluent released contains diverse contaminants such as tensoactives, disinfectants, metals, pharmaceutical products and chemical reagents, which are potentially toxic to the environment since they receive no treatment or are not effectively removed by such treatment before entering the drain. they are incorporated into municipal wastewater, eventually entering water bodies where they can have harmful effects on organisms and can ...201829751329
yokukansan contains compounds that antagonize the 5-ht3 receptor.we recently focused on alkaloids in uncaria hook (a constituent of the kampo medicine, yokukansan) and identified the pharmacological action of geissoschizine methyl ether on several g protein-coupled receptors. however, the functions of other identified alkaloids in uncaria hook, including hirsutine, hirsuteine, rhynchophylline, isorhynchophylline, corynoxeine, isocorynoxeine, are not clear.201829747744
foxo4 activity is regulated by phosphorylation and the cellular environment during dehydration in the african clawed frog, xenopus laevis.the african clawed frog, xenopus laevis, is capable of enduring seasonal bouts of severe dehydration stress resulting from transcriptional regulation that facilitates a pro-survival response. previous studies have shown that dehydration increases antioxidant gene expression in this amphibian. as foxo4 is known to regulate several antioxidant genes, we sought to understand how differential phosphorylation and environmental factors (urea, temperature) may contribute to its transcriptional regulati ...201829746959
mechanism of how augmin directly targets the γ-tubulin ring complex to microtubules.microtubules (mts) must be generated from precise locations to form the structural frameworks required for cell shape and function. mts are nucleated by the γ-tubulin ring complex (γ-turc), but it remains unclear how γ-turc gets to the right location. augmin has been suggested to be a γ-turc targeting factor and is required for mt nucleation from preexisting mts. to determine augmin's architecture and function, we purified xenopus laevis augmin from insect cells. we demonstrate that augmin is su ...201829875259
living xenopus oocytes, eggs, and embryos as models for cell division.xenopus laevis has long been a popular model for studies of development and, based on the use of cell-free extracts derived from its eggs, as a model for reconstitution of cell cycle regulation and other basic cellular processes. however, work over the last several years has shown that intact xenopus eggs and embryos are also powerful models for visualization and characterization of cell cycle-regulated cytoskeletal dynamics. these findings were something of a surprise, given that the relatively ...201829804672
conserved rna binding activity of a yin-yang 1 homologue in the ova of the purple sea urchin strongylocentrotus purpuratus.yin-yang 1 (yy1) is a highly conserved transcription factor possessing rna-binding activity. a putative yy1 homologue was previously identified in the developmental model organism strongylocentrotus purpuratus (the purple sea urchin) by genomic sequencing. we identified a high degree of sequence similarity with yy1 homologues of vertebrate origin which shared 100% protein sequence identity over the dna- and rna-binding zinc-finger region with high similarity in the n-terminal transcriptional act ...201829795182
spiral waves and vertebrate embryonic handedness.during early embryonic development, the vertebrate main body axis is segmented from head-to-tail into somites. somites emerge sequentially from the presomitic mesoderm (psm) as a consequence of oscillatory waves of genetic activity, called somitogenesis waves. here, we discuss the implications of the dynamic patterns of early x-delta-2 expression in the prospective somites (somitomeres) of xenopus laevis. we report that right somitomeres normally emerge before left to form chiral structures (i.e ...201829872025
nmda receptor signaling is important for neural tube formation and for preventing antiepileptic drug-induced neural tube defects.failure of neural tube closure leads to neural tube defects (ntds), which can have serious neurological consequences or be lethal. use of antiepileptic drugs (aeds) during pregnancy increases the incidence of ntds in offspring by unknown mechanisms. here we show that during xenopus laevis neural tube formation, neural plate cells exhibit spontaneous calcium dynamics that are partially mediated by glutamate signaling. we demonstrate that nmda receptors are important for the formation of the neura ...201829712790
xenopus laevis oocyte as a model for the study of the cytoskeleton.at the beginning of diplotene, the oocyte of xenopus laevis is a cell of about 10-20 microns destined to increase 10,000-fold its size when the oocyte becomes filled with yolk platelets and has accumulated a great number of pigment granules in a half of its periphery. its internal architecture is gradually accomplished during growth because of several factors, especially because of cytoskeletal changes. in the fully-grown oocyte, the cytoskeleton appears to sustain the eccentrically located germ ...201829705198
roles of xenopus chemokine ligand cxclh (xcxclh) in early embryogenesis.several chemokine molecules control cell movements during early morphogenesis. however, it is unclear whether chemokine molecules affect cell fate. here, we identified and characterized the cxc-type chemokine ligand in xenopus laevis, xenopus cxclh (xcxclh), during early embryogenesis. xcxclh is expressed in the dorsal vegetal region at the gastrula stage. both overexpression and knockdown of xcxclh in the dorsal region inhibited gastrulation. xcxclh contributed to the attraction of mesendoderma ...201829700804
effect of hemin, baicalein and heme oxygenase-1 (ho-1) enzyme activity inhibitors on cd-induced accumulation of ho-1, hsps and aggresome-like structures in xenopus kidney epithelial cells.cadmium is a highly toxic environmental pollutant that can cause many adverse effects including cancer, neurological disease and kidney damage. aquatic amphibians are particularly susceptible to this toxicant as it was shown to cause developmental abnormalities and genotoxic effects. in mammalian cells, the accumulation of heme oxygenase-1 (ho-1), which catalyzes the breakdown of heme into co, free iron and biliverdin, was reported to protect cells against potentially lethal concentrations of cd ...201829698685
microvascular anatomy of the brain of the adult pipid frog, xenopus laevis (daudin): a scanning electron microscopic study of vascular corrosion casts.to demonstrate the 3d microvascular anatomy of the brain of the model organism xenopus laevis daudin scanning electron microscopy of vascular corrosion casts was correlated with light microscopy of stained 7 µm thick serial tissues sections. results showed that supplying arteries descended from the leptomeningeal surface without remarkable branchings straight to the subventricular zone where they branched and capillarized. capillaries showed few h- and/or y-shaped anastomoses during their centri ...201829693258
developmental toxicity of dibutyl phthalate and citrate ester plasticizers in xenopus laevis embryos.citrate esters have been considered as alternatives to phthalate plasticizers. being considered to have low toxicity in mammals, their toxicological information for aquatic animals remains poorly understood. we examined the developmental toxicity of citrate esters including tributyl o-acetylcitrate (atbc), triethyl 2-acetylcitrate (atec), and trihexyl o-acetylcitrate (athc) together with dibutyl phthalate (dbp) based on the frog embryo teratogenesis assay-xenopus (fetax). atbc has the lowest 96  ...201829684872
akt signaling displays multifaceted functions in neural crest development.akt signaling is an essential intracellular pathway controlling cell homeostasis, cell proliferation and survival, as well as cell migration and differentiation in adults. alterations impacting the akt pathway are involved in many pathological conditions in human disease. similarly, during development, multiple transmembrane molecules, such as fgf receptors, pdgf receptors or integrins, activate akt to control embryonic cell proliferation, migration, differentiation, and also cell fate decisions ...201829859890
a novel clcn5 pathogenic mutation supports dent disease with normal endosomal acidification.dent disease is an x-linked recessive renal tubular disorder characterized by low-molecular-weight proteinuria, hypercalciuria, nephrolithiasis, nephrocalcinosis, and progressive renal failure. inactivating mutations of clcn5, the gene encoding the 2cl- /h+ exchanger clc-5, have been reported in patients with dent disease 1. in vivo studies in mice harboring an artificial mutation in the "gating glutamate" of clc-5 (c.632a > c, p.glu211ala) and mathematical modeling suggest that endosomal chlori ...201829791050
rod-specific ablation using the nitroreductase/metronidazole system to investigate regeneration in xenopus.genetically controlled cell type-specific ablation provides a reproducible method to induce regeneration that can be temporally and spatially controlled. until recently, regeneration studies in xenopus have relied on surgical methods to stimulate regeneration. these methods are labor intensive and not as reproducible as a genetically controlled approach. in this protocol we describe selective ablation of rod photoreceptors in the premetamorphic xenopus laevis retina using the nitroreductase/metr ...201829789402
rxr ligands modulate thyroid hormone signaling competence in young xenopus laevis tadpoles.appropriate thyroid hormone (th) signaling through thyroid hormone receptors (trs) is essential for vertebrate development. amphibian metamorphosis is initiated and sustained through the action of th on trs, which are conserved across vertebrates. trs heterodimerize with retinoid x receptors (rxrs) on thyroid hormone response elements (tres) in the genome; however, in most cell line and adult animal studies, rxr ligands do not affect expression of tr target genes. we used a quantitative, precoci ...201829762675
methods for investigating the larval period and metamorphosis in xenopus.anuran metamorphosis resembles postembryonic development in mammals, a period around birth when many organs/tissues mature into their adult form as circulating thyroid and stress hormone levels are high. unlike uterus-enclosed mammalian embryos, tadpoles develop externally and undergo the dramatic changes of hormone-dependent development totally independent of maternal influence, making them a valuable model in which to study vertebrate postembryonic organ development and maturation. various pro ...201829769395
infrared laser-mediated gene induction at the single-cell level in the regenerating tail of xenopus laevis tadpoles.we describe a precise and reproducible gene-induction method in the amphibian, xenopus laevis tetrapod amphibians are excellent models for studying the mechanisms of three-dimensional organ regeneration because they have an exceptionally high regenerative ability. however, spatial and temporal manipulation of gene expression has been difficult in amphibians, hindering studies on the molecular mechanisms of organ regeneration. recently, however, development of a xenopus transgenic system with a h ...201829769391
developmental expression profiles and thyroidal regulation of cytokines during metamorphosis in the amphibian xenopus laevis.early life-stages of amphibians rely on the innate immune system for defense against pathogens. while thyroid hormones (th) are critical for metamorphosis and later development of the adaptive immune system, the role of th in innate immune system development is less clear. an integral part of the innate immune response are pro-inflammatory cytokines - effector molecules that allow communication between components of the immune system. the objective of this study was to characterize the expressio ...201829656046
new targets for old drugs: cardiac glycosides inhibit atrial-specific k2p3.1 (task-1) channels.cardiac glycosides have been used in the treatment of arrhythmias for more than 200 years. two-pore-domain (k2p) potassium channels regulate cardiac action potential repolarization. recently, k2p3.1 [tandem of p domains in a weak inward rectifying k+ channel (twik)-related acid-sensitive k+ channel (task)-1] has been implicated in atrial fibrillation pathophysiology and was suggested as an atrial-selective antiarrhythmic drug target. we hypothesized that blockade of cardiac k2p channels contribu ...201829643254
cell transplantation as a method to investigate spinal cord regeneration in regenerative and nonregenerative xenopus stages.mammals are not capable of regenerating their central nervous system (cns); anamniotes, however, can regenerate in response to injury. the mechanisms that explain the different regenerative capabilities include: (i) extrinsic mechanisms that consider the cellular environment and extracellular matrix composition, (ii) intrinsic factors implicating the presence or absence of genetic programs that promote axon regeneration, and (iii) the presence or absence of neural stem and progenitors cells (nsp ...201829769390
expression variation and covariation impair analog and enable binary signaling control.due to noise in the synthesis and degradation of proteins, the concentrations of individual vertebrate signaling proteins were estimated to vary with a coefficient of variation (cv) of approximately 25% between cells. such high variation is beneficial for population-level regulation of cell functions but abolishes accurate single-cell signal transmission. here, we measure cell-to-cell variability of relative protein abundance using quantitative proteomics of individual xenopus laevis eggs and cu ...201829759982
identification of loop d domain amino acids in the human aquaporin-1 channel involved in activation of the ionic conductance and inhibition by aqb011.aquaporins are integral proteins that facilitate the transmembrane transport of water and small solutes. in addition to enabling water flux, mammalian aquaporin-1 (aqp1) channels activated by cyclic gmp can carry non-selective monovalent cation currents, selectively blocked by arylsulfonamide compounds aqb007 (ic50 170 μm) and aqb011 (ic50 14 μm). in silico models suggested that ligand docking might involve the cytoplasmic loop d (between aqp1 transmembrane domains 4 and 5), but the predicted si ...201829755973
deciphering the molecular determinants of cholinergic anthelmintic sensitivity in nematodes: when novel functional validation approaches highlight major differences between the model caenorhabditis elegans and parasitic species.cholinergic agonists such as levamisole and pyrantel are widely used as anthelmintics to treat parasitic nematode infestations. these drugs elicit spastic paralysis by activating acetylcholine receptors (achrs) expressed in nematode body wall muscles. in the model nematode caenorhabditis elegans, genetic screens led to the identification of five genes encoding levamisole-sensitive-achr (l-achr) subunits: unc-38, unc-63, unc-29, lev-1 and lev-8. these subunits form a functional l-achr when hetero ...201829719008
transposable elements and polyploid evolution in animals.polyploidy in animals is much less common than in plants, where it is thought to be pervasive in all higher plant lineages. recent studies have highlighted the impact of polyploidization and the associated process of diploidy restoration on the evolution and speciation of selected taxonomic groups in the animal kingdom: from vertebrates represented by salmonid fishes and african clawed frogs to invertebrates represented by parasitic root-knot nematodes and bdelloid rotifers. in this review, we f ...201829715568
premotor neuron divergence reflects vocal evolution.to identify mechanisms of behavioral evolution, we investigated the hindbrain circuit that generates distinct vocal patterns in two closely related frog species. male xenopus laevis and xenopus petersii produce courtship calls that include a fast trill: trains of ∼60 hz sound pulses. although fast trill rates are similar, x. laevis fast trills have a longer duration and period than those of x. petersii to pinpoint the neural basis of these differences, we used whole-cell patch-clamp recordings i ...201829875228
molecular insights into variable electron transfer in amphibian cryptochrome.cryptochrome proteins are activated by the absorption of blue light, leading to the formation of radical pairs through electron transfer in the active site. recent experimental studies have shown that once some of the amino acid residues in the active site of xenopus laevis cryptochrome dash are mutated, radical-pair formation is still observed. in this study, we computationally investigate electron-transfer pathways in the x. laevis cryptochrome dash by extensively equilibrating a previously es ...201829874607
new apetx-like peptides from sea anemone heteractis crispa modulate asic1a channels.sea anemones are an abundant source of various biologically active peptides. the hydrophobic 20% ethanol fraction of tropical sea anemone heteractis crispa was shown to contain at least 159 peptide compounds including neurotoxins, proteinase and α-amylase inhibitors, as well as modulators of acid-sensing ion channels (asics). the three new peptides, π-anmtx hcr 1b-2, -3, and -4 (41 aa) (short names hcr 1b-2, -3, -4), identified by a combination of reversed-phase liquid chromatography and mass sp ...201829684594
comparison of oocyte mrna localization patterns in sterlet acipenser ruthenus and african clawed frog xenopus laevis.in oocytes, rna localization has critical implications, as assembly of proteins in particular subcellular domains is crucial to embryo development. the distribution of mrna molecules can identify and characterize localized transcripts. the goal of this study was to clarify the origin of primordial germ cells in the oocyte body plan and to reveal the generation of cell lineages by localized rnas. the distribution of 12 selected mrnas in sterlet acipenser ruthenus oocytes was investigated by qpcr ...201829682883
cardiac regeneration in xenopus tropicalis and xenopus laevis: discrepancies and problems.two studies have recently focused on adult heart regeneration in xenopus. while we reported on cardiac myogenic regeneration in xenopus tropicalis after injury, marshall and colleagues found no regeneration in an injured heart in xenopus laevis. here, we would like to join the discussion initiated by marshall et al. who debated the methods and species differences in both studies. we agree with their view that the species difference in cardiac regenerative capacity could lead to different results ...201829713455
is adult cardiac regeneration absent in xenopus laevis yet present in xenopus tropicalis?we recently used an endoscopy-based resection method to explore the consequences of cardiac injury in adult xenopus laevis, obtaining the result that the adult xenopus heart is unable to regenerate. at 11 months post-amputation, cellular and biological marks of scarring persisted. we thus concluded that, contrary to urodeles and teleosts, adult anurans share a cardiac injury outcome similar to adult mammals. however, in their work published in this journal on the 13 december 2017, liao et al. sh ...201829713454
retinoic acid-induced expression of hnf1b and fzd4 is required for pancreas development in xenopus laevis.retinoic acid (ra) is required for pancreas specification in xenopus and other vertebrates. however, the gene network that is directly induced by ra signalling in this context remains to be defined. by rna sequencing of in vitro-generated pancreatic explants, we identified the genes encoding the transcription factor hnf1β and the wnt-receptor fzd4/fzd4s as direct ra target genes. functional analyses of hnf1b and fzd4/fzd4s in programmed pancreatic explants and whole embryos revealed their requir ...201829769220
coulomb and ch-π interactions in (6-4) photolyase-dna complex dominate dna binding and repair abilities.(6-4) photolyases ((6-4)pls) are flavoenzymes that repair the carcinogenic uv-induced dna damage, pyrimidine(6-4)pyrimidone photoproducts ((6-4)pps), in a light-dependent manner. although the reaction mechanism of dna photorepair by (6-4)pls has been intensively investigated, the molecular mechanism of the lesion recognition remains obscure. we show that a well-conserved arginine residue in xenopus laevis (6-4)pl (xl64) participates in dna binding, through coulomb and ch-π interactions. fragment ...201829762762
effects of multiple life stage exposure to the fungicide prochloraz in xenopus laevis: manifestations of antiandrogenic and other modes of toxicity.the larval amphibian growth and development assay (lagda) is an internationally harmonized testing guideline for evaluating effects of chronic chemical exposure in amphibians. in order to evaluate the effects of chronic exposure to an antiandrogenic chemical in an amphibian model, prochloraz was tested using a variation of the lagda design. exposure was initiated with <1d post-fertilization embryos at nominal concentrations of 0, 6.7, 20, 60 and 180 μg/l (0, 18, 53, 159, 478 nm) and continued in ...201829674245
fluorescent anesthetics.methods for using exogenous fluorophore and general anesthetic 1-aminoanthracene (1-ama) and its photoactive derivative 1-azidoanthracene (1-aza) are provided. 1-ama potentiates gabaa chloride currents and immobilizes xenopus laevis tadpoles. cellular and tissue anesthetic distribution can be imaged for quantifying "on-pathway" and "off-pathway" targets. 1-aza shares targets with 1-ama and offers further optoanesthetic spatial and temporal control upon near-uv laser irradiation. furthermore, 1-a ...201829673536
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