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species specific rna a-to-i editing of mosquito rdl modulates gaba potency and influences agonistic, potentiating and antagonistic actions of ivermectin.the insect gaba receptor, rdl, is the target of several classes of pesticides. the peptide sequences of rdl are generally highly conserved between diverse insects. however, rna a-to-i editing can effectively alter amino acid residues of rdl in a species specific manner, which can affect the potency of gaba and possibly insecticides. we report here that rna a-to-i editing alters the gene products of rdl in three mosquito disease vectors, recoding five amino acid residues in rdl of aedes aegypti a ...201729223796
xenopus laevis as a model organism for the study of spinal cord formation, development, function and regeneration.the spinal cord is the first central nervous system structure to develop during vertebrate embryogenesis, underscoring its importance to the organism. because of its early formation, accessibility to the developing spinal cord in amniotes is challenging, often invasive and the experimental approaches amenable to model systems like mammals are limited. in contrast, amphibians, in general and the african-clawed frog xenopus laevis, in particular, offer model systems in which the formation of the s ...201729218002
interaction of purinergic p2x4 and p2x7 receptor subunits.p2x4 and p2x7 are members of the p2x receptor family, comprising seven isoforms (p2x1-p2x7) that form homo- and heterotrimeric non-specific cation channels gated by extracellular atp. p2x4 and p2x7 are widely coexpressed, particularly in secretory epithelial cells and immune and inflammatory cells, and regulate inflammation and nociception. although functional heteromerization has been established for p2x2 and p2x3 subunits expressed in sensory neurons, there are contradictory reports regarding ...201729213241
spindle-to-cortex communication in cleaving frog eggs.during cytokinesis, the mitotic spindle communicates with the cell cortex to position a cleavage furrow that will cut through the cell in the plane defined by the metaphase plate. we investigated the molecular basis of this communication in xenopus laevis eggs, where the signal has to travel ∼400 µm in ∼30 min to reach the cortex from the first anaphase spindle. at anaphase onset, huge microtubule asters grow out from the poles of the spindle and meet at the plane previously defined by the metap ...201729196560
the ectodomain of cadherin-11 binds to erbb2 and stimulates akt phosphorylation to promote cranial neural crest cell migration.during development, a multi-potent group of cells known as the cranial neural crest (cnc) migrate to form craniofacial structures. proper migration of these cells requires proteolysis of cell adhesion molecules, such as cadherins. in xenopus laevis, preventing extracellular cleavage of cadherin-11 impairs cnc migration. however, overexpression of the soluble cleavage product (ec1-3) is capable of rescuing this phenotype. the mechanism by which ec1-3 promotes cnc migration has not been investigat ...201729190819
tissue-specific gene inactivation in xenopus laevis: knockout of lhx1 in the kidney with crispr/cas9.studying genes involved in organogenesis is often difficult because many of these genes are also essential for early development. the allotetraploid frog, xenopus laevis, is commonly used to study developmental processes, but because of the presence of two homeologs for many genes, it has been difficult to use as a genetic model. few studies have successfully used crispr in amphibians, and currently there is no tissue-targeted knockout strategy described in xenopus the goal of this study is to d ...201729187504
evaluating the longevity of surgically extracted xenopus laevis oocytes for the study of nematode ligand-gated ion channels.xenopus laevis oocytes have been extensively used as a heterologous expression system for the study of ion channels. while used successfully worldwide as tool for expressing and characterizing ion channels from a wide range of species, the limited longevity of oocytes once removed from the animal can pose significant challenges. in this study, we evaluate a simple and useful method that extends the longevity of xenopus oocytes after removal from the animal and quantitatively assessed the reliabi ...201729185074
quantification of size effect on protein rotational mobility in cells by 19f nmr spectroscopy.protein diffusion in living cells might differ significantly from that measured in vitro. little is known about the effect of globular protein size on rotational diffusion in cells because each protein has distinct surface properties, which result in different interactions with cellular components. to overcome this problem, the b1 domain of protein g (gb1) and several concatemers of the protein were labeled with 5-fluorotryptophan and studied by 19f nmr in escherichia coli cells, xenopus laevis ...201729184995
the r81t mutation in the nicotinic acetylcholine receptor of aphis gossypii is associated with neonicotinoid insecticide resistance with differential effects for cyano- and nitro-substituted neonicotinoids.the cotton aphid, aphis gossypii glover, is one of the most agriculturally important insect pests. neonicotinoid insecticides and sulfoxaflor have generally shown excellent control of a. gossypii, but these aphids have recently developed resistance against neonicotinoid insecticides. we previously characterized a field-collected a. gossypii kushima clone that showed higher resistance to nitro-substituted neonicotinoids, such as imidacloprid, than to cyano-substituted neonicotinoids, such as acet ...201729183611
targeted base editing via rna-guided cytidine deaminases in xenopus laevis embryos.genome editing using programmable nucleases such as crispr/cas9 or cpf1 has emerged as powerful tools for gene knock-out or knock-in in various organisms. while most genetic diseases are caused by point mutations, these genome-editing approaches are inefficient in inducing single-nucleotide substitutions. recently, cas9-linked cytidine deaminases, named base editors (bes), have been shown to convert cytidine to uridine efficiently, leading to targeted single-base pair substitutions in human cell ...201729179261
rna helicase mov10 is essential for gastrulation and cns development.mov10 is an rna helicase that modulates access of argonaute 2 to microrna recognition elements in mrnas. we examined the role of mov10 in xenopus laevis development and show a critical role for mov10 in gastrulation and in the development of the central nervous system.201729266590
dynamic intramolecular regulation of the histone chaperone nucleoplasmin controls histone binding and release.nucleoplasmin (npm) is a highly conserved histone chaperone responsible for the maternal storage and zygotic release of histones h2a/h2b. npm contains a pentameric n-terminal core domain and an intrinsically disordered c-terminal tail domain. though intrinsically disordered regions are common among histone chaperones, their roles in histone binding and chaperoning remain unclear. using an nmr-based approach, here we demonstrate that the xenopus laevis npm tail domain controls the binding of hist ...201729263320
differentiation-dependent antiviral capacities of amphibian (xenopus laevis) macrophages.infections by ranaviruses such as frog virus 3 (fv3) are significantly contributing to the worldwide amphibian population declines. notably, amphibian macrophages (mφs) are important to both the fv3 infection strategies and the immune defense against this pathogen. however, the mechanisms underlying amphibian mφ fv3 susceptibility and resistance remain unknown. mφ differentiation is mediated by signaling through the colony-stimulating factor-1 receptor (csf-1r), which is now known to be bound by ...201729259133
tight junctions negatively regulate mechanical forces applied to adherens junctions in vertebrate epithelial tissue.epithelia are layers of polarised cells tightly bound to each other by adhesive contacts. epithelia act as barriers between an organism and its external environment. understanding how epithelia maintain their essential integrity while remaining sufficiently plastic to allow events such as cytokinesis to take place is a key biological problem. in vertebrates, the remodelling and reinforcement of adherens junctions maintains epithelial integrity during cytokinesis. the involvement of tight junctio ...201729246943
proton-independent activation of acid-sensing ion channel asic3 by alkaloid lindoldhamine from laurus nobilis.acid-sensing ion channels (asics) play an important role in synaptic plasticity and learning, as well as in nociception and mechanosensation. asics are implicated in pain, neurological and psychiatric diseases but their therapeutic potential is limited by lack of ligands activating them at physiological ph.201729277899
direct modification of the 5-ht3 receptor current by some anticancer drugs.the serotonin (5-hydroxytryptamine) type 3 (5-ht3) receptor is an important target in the control of emesis, and 5-ht3 receptor antagonists are effective against the early phase chemotherapy evoked vomiting. we recently reported that the anticancer drugs irinotecan and topotecan directly modulate the 5-ht-mediated 5-ht3 receptor current in vitro. in addition, the drug response depends on the 5-ht3 subunit composition. here, we explored the effects of 35 anticancer drugs on the 5-ht3 receptor cur ...201729277715
spinal cord cells from pre-metamorphic stages differentiate into neurons and promote axon growth and regeneration after transplantation into the injured spinal cord of non-regenerative xenopus laevis froglets.mammals are unable to regenerate its spinal cord after a lesion, meanwhile, anuran amphibians are capable of spinal cord regeneration only as larvae, and during metamorphosis, this capability is lost. sox2/3+ cells present in the spinal cord of regenerative larvae are required for spinal cord regeneration. here we evaluate the effect of the transplantation of spinal cord cells from regenerative larvae into the resected spinal cord of non-regenerative stages (nr-stage). donor cells were able to s ...201729326551
analysis of cell size in the gastrula of ten frog species reveals a correlation of egg with cell sizes, and a conserved pattern of small cells in the marginal zone.we investigated the relationship between egg and cell sizes in the early gastrula of ten species of frogs with eggs of 1,100-3,500 μm diameters. we asked whether differences in cell size of the vegetal region, blastocoel roof, and marginal zone of the early gastrula were associated with egg size. alternatively, we proposed that cell size differences may associate with gastrulation characteristics. the analyzed species were as follows: xenopus laevis, engystomops randi, engystomops coloradorum, e ...201727381278
three-dimensional reconstruction of the cranial and anterior spinal nerves in early tadpoles of xenopus laevis (pipidae, anura).xenopus laevis is one of the most widely used model organism in neurobiology. it is therefore surprising, that no detailed and complete description of the cranial nerves exists for this species. using classical histological sectioning in combination with fluorescent whole mount antibody staining and micro-computed tomography we prepared a detailed innervation map and a freely-rotatable three-dimensional (3d) model of the cranial nerves and anterior-most spinal nerves of early x. laevis tadpoles. ...201729218708
effects of a commonly used glyphosate-based herbicide formulation on early developmental stages of two anuran species.environmental contamination, especially due to the increasing use of pesticides, is suggested to be one out of six main reasons for the global amphibian decline. adverse effects of glyphosate-based herbicides on amphibians have been already discussed in several studies with different conclusions, especially regarding sublethal effects at environmentally relevant concentrations. therefore, we studied the acute toxic effects (mortality, growth, and morphological changes) of the commonly used glyph ...201727785717
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
comparative micrornaome analysis of the testis and ovary of the chinese giant salamander.micrornas (mirnas) are 18-24 nucleotides non-coding rnas that regulate gene expression by post-transcriptional suppression of mrna. the chinese giant salamander (cgs, andrias davidianus), which is an endangered species, has become one of the important models of animal evolution; however, no mirna studies on this species have been conducted. in this study, two small rna libraries of cgs ovary and testis were constructed using deep sequencing technology. a bioinformatics pipeline was developed to ...201728630098
genomic epidemiology of the emerging pathogen batrachochytrium dendrobatidis from native and invasive amphibian species in chile.emerging fungal diseases represent a threat to food security, animal and human health worldwide. amphibian chytridiomycosis, caused by the fungus batrachochytrium dendrobatidis (bd), has been associated with catastrophic and well-documented amphibian population declines and extinctions. for the first time, bd was cultured from native and non-native wild amphibians in chile. phylogenomic analyses revealed that chilean isolates avs2, avs4 and avs7 group within the global panzootic lineage of bd (b ...201729205924
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
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
amphibase: a new genomic resource for non-model amphibian species.more than five thousand genes annotated in the recently published xenopus laevis and xenopus tropicalis genomes do not have a candidate orthologous counterpart in other vertebrate species. to determine whether these sequences represent genuine amphibian-specific genes or annotation errors, it is necessary to analyze them alongside sequences from other amphibian species. however, due to large genome sizes and an abundance of repeat sequences, there are limited numbers of gene sequences available ...201728095648
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
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
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
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
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
pharmacological characterization of histamine-gated chloride channels from the housefly musca domestica.the biogenic amine histamine (ha) is not only the neurotransmitter of photoreceptors but also has important roles in mechanosensory reception, temperature preference, sleep and olfactory processing in insects. two cdnas (mdhcla and mdhclb) that encode ha-gated chloride channel subunits (mdhcla and mdhclb) were cloned from the housefly musca domestica. the crnas were injected into xenopus laevis oocytes to examine the functions and pharmacological characteristics of mdhcla and mdhclb channels usi ...201727139242
expression pattern and pharmacological characterisation of two novel alternative splice variants of the glutamate-gated chloride channel in the small brown planthopper laodelphax striatellus.glutamate-gated chloride channels (glucl) mediate fast inhibitory neurotransmission in invertebrate nervous systems. although only one glucl gene was presented in insects, it showed diverse alternative splicing that was speculated could affect channel function and pharmacology.201727302648
in vitro models of cranial neural crest development toward toxicity tests: frog, mouse, and human.during craniofacial development, cranial neural crest (nc)-derived mesenchymal cells migrate to pharyngeal arches and contribute extensively to neurons, schwann cells, smooth muscle cells, osteoblasts, chondrocytes, and odontoblasts, forming maxillofacial structures. in vitro models using model organism cells, such as african clawed frog (xenopus laevis) and mouse (mus musculus), were developed to understand cellular and molecular mechanisms of cranial nc development. recent studies using human ...201727299949
sex chromosome differentiation and the w- and z-specific loci in xenopus laevis.genetic sex-determining systems in vertebrates include two basic types of heterogamety; xx (female)/xy (male) and zz (male)/zw (female) types. the african clawed frog xenopus laevis has a zz/zw-type sex-determining system. in this species, we previously identified a w-specific sex (female)-determining gene dmw, and specified w and z chromosomes, which could be morphologically indistinguishable (homomorphic). in addition to dmw, we most recently discovered two genes, named scanw and ccdc69w, and ...201727297884
genes coding for cyclin-dependent kinase inhibitors are fragile in xenopus.cell proliferation is strictly regulated by the dosage balance among cell-cycle regulators such as cdk/cyclin complexes and cdk-inhibitors. even in the allotetraploid genome of xenopus laevis, the dosage balance must be maintained for animals to stay alive, and the duplicated homeologous genes seem to have gradually changed, through evolution, resulting in the best genes for them to thrive. in the xenopus laevis genome, while homeologous gene pairs of cdks are fundamentally maintained and a few ...201727393661
gene expression analysis of developing cell groups in the pretectal region of xenopus laevis.our previous analysis of progenitor domains in the pretectum of xenopus revealed three molecularly distinct anteroposterior subdivisions, identified as precommissural (pcp), juxtacommissural (jcp), and commissural (cop) histogenetic domains (morona et al. [2011] j comp neurol 519:1024-1050). here we analyzed at later developmental stages the nuclei derived from these areas, attending to their gene expression patterns and histogenesis. transcription-factor gene markers were used to selectively ma ...201727539385
electrophysiological actions of synthetic cathinones on monoamine transporters.products containing psychoactive synthetic cathinones, such as mephedrone and 3,4-methylenedioxypyrovalerone (mdpv) are prevalent in our society. synthetic cathinones are structurally similar to methamphetamine, and numerous synthetics have biological activity at dopamine, serotonin, and norepinephrine transporters. importantly, monoamine transporters co-transport sodium ions along with their substrate, and movement of substrates and ions through the transporter can generate measurable ionic cur ...201727677783
xenmine: a genomic interaction tool for the xenopus community.the xenopus community has embraced recent advances in sequencing technology, resulting in the accumulation of numerous rna-seq and chip-seq datasets. however, easily accessing and comparing datasets generated by multiple laboratories is challenging. thus, we have created a central space to view, search and analyze data, providing essential information on gene expression changes and regulatory elements present in the genome. xenmine (www.xenmine.org) is a user-friendly website containing publishe ...201727157655
xenopus genomic data and browser resources.the two species of xenopus most commonly used in biomedical research are the diploid xenopus (silurana) tropicalis and the tetraploid xenopus laevis. the x. tropicalis genome sequence has been available since 2010 and this year the x. laevis, genome from two distinct genetic backgrounds has been published. multiple genome assemblies available for both species and transcriptomic and epigenetic data sets are growing rapidly, all of which are available from a variety of web resources. this review d ...201727039265
expanding the genetic toolkit in xenopus: approaches and opportunities for human disease modeling.the amphibian model xenopus, has been used extensively over the past century to study multiple aspects of cell and developmental biology. xenopus offers advantages of a non-mammalian system, including high fecundity, external development, and simple housing requirements, with additional advantages of large embryos, highly conserved developmental processes, and close evolutionary relationship to higher vertebrates. there are two main species of xenopus used in biomedical research, xenopus laevis ...201727109192
genome-wide analysis of dorsal and ventral transcriptomes of the xenopus laevis gastrula.rna sequencing has allowed high-throughput screening of differential gene expression in many tissues and organisms. xenopus laevis is a classical embryological and cell-free extract model system, but its genomic sequence had been lacking due to difficulties arising from allotetraploidy. there is currently much excitement surrounding the release of the completed x. laevis genome (version 9.1) by the joint genome institute (jgi), which provides a platform for genome-wide studies. here we present a ...201727016259
evaluating the teratogenicity of the selective ß3-adrenoceptor agonist, cl 316.243 hydrate by employing fetax (frog embryo teratogenesis assay).in this study, the frog embryo teratogenesis assay (fetax - xenopus) technique was employed to evaluate the potential teratogenicity of the selective ß-adrenoceptor (ar) agonist, cl 316.243. in this context, cl 316.243 was applied to the south african clawed frog (xenopus laevis) embryos. the media containing the cl 316.24-exposed embryos were monitored and changed/replaced once every 24 hours. using fetax, we determined the minimum concentrations to inhibit growth (mcig) for cl 316.243. the 96- ...201727063898
evaluation of microtransplantation of rat brain neurolemma into xenopus laevis oocytes as a technique to study the effect of neurotoxicants on endogenous voltage-sensitive ion channels.microtransplantation of mammalian brain neurolemma into the plasma membrane of xenopus oocytes is used to study ion channels in their native form as they appear in the central nervous system. use of microtransplanted neurolemma is advantageous for various reasons: tissue can be obtained from various sources and at different developmental stages; ion channels and receptors are present in their native configuration in their proper lipid environment along with appropriate auxiliary subunits; allowi ...201727063102
generation of a xenopus laevis f1 albino j strain by genome editing and oocyte host-transfer.completion of the xenopus laevis genome sequence from inbred j strain animals has facilitated the generation of germline mutant x. laevis using targeted genome editing. in the last few years, numerous reports have demonstrated that talens are able to induce mutations in f0 xenopus embryos, but none has demonstrated germline transmission of such mutations in x. laevis. in this report we used the oocyte host-transfer method to generate mutations in both tyrosinase homeologs and found highly-penetr ...201726993591
xenopus: leaping forward in kidney organogenesis.while kidney donations stagnate, the number of people in need of kidney transplants continues to grow. although transplanting culture-grown organs is years away, pursuing the engineering of the kidney de novo is a valid means of closing the gap between the supply and demand of kidneys for transplantation. the structural organization of a mouse kidney is similar to that of humans. therefore, mice have traditionally served as the primary model system for the study of kidney development. the mouse ...201727099217
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
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
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
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
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
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
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
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
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
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
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
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
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
spindle assembly in egg extracts of the marsabit clawed frog, xenopus borealis.egg extracts of the african clawed frog xenopus laevis have provided a cell-free system instrumental in elucidating events of the cell cycle, including mechanisms of spindle assembly. comparison with extracts from the diploid western clawed frog, xenopus tropicalis, which is smaller at the organism, cellular and subcellular levels, has enabled the identification of spindle size scaling factors. we set out to characterize the marsabit clawed frog, xenopus borealis, which is intermediate in size b ...201829573195
cell cycles during early steps of amphibian embryogenesis: a review.the published data on cell cycles during the initial (pregastrular) period of embryonic development in representatives of the class amphibia have been critically discussed. we have also used the literature data on ontogenetic diversity of these animals. the relatively small eggs of two principal model species for amphibian embryology, the mexican axolotl and the african clawed frog, undergo the extensive series of rapid synchronous cleavage divisions, after which the midblastula transition (mbt) ...201830240720
the tmem16a channel mediates the fast polyspermy block in xenopus laevis.in externally fertilizing animals, such as sea urchins and frogs, prolonged depolarization of the egg immediately after fertilization inhibits the entry of additional sperm-a phenomenon known as the fast block to polyspermy. in the african clawed frog xenopus laevis, this depolarization is driven by ca2+-activated cl- efflux. although the prominent ca2+-activated cl- currents generated in immature x. laevis oocytes are mediated by x. laevis transmembrane protein 16a (xtmem16a) channels, little i ...201830012842
skin regeneration of amphibians: a novel model for skin regeneration as adults.adult mammals do not regenerate the dermis of the skin but form a scar after a deep skin injury. since a scar causes serious medical problems, skin regeneration, instead of formation of a scar, has been strongly desired from a clinical point of view. recent studies have suggested multiple origins of myofibroblasts, which are scar-forming cells in skin wound healing of mammals. while amphibians have skin structures that are basically common to mammals as tetrapods, both urodele and anuran amphibi ...201829947057
bapx1 upregulation is associated with ectopic mandibular cartilage development in amphibians.the emergence of novel structures during evolution is crucial for creating variation among organisms, but the underlying processes which lead to the emergence of evolutionary novelties are poorly understood. the gnathostome jaw joint is such a novelty, and the incorporation of bapx1 expression into the intermediate first pharyngeal arch may have played a major role in the evolution of this joint. knockdown experiments revealed that loss of bapx1 function leads to the loss of the jaw joint, becau ...201829942645
musashi and plasticity of xenopus and axolotl spinal cord ependymal cells.the differentiated state of spinal cord ependymal cells in regeneration-competent amphibians varies between a constitutively active state in what is essentially a developing organism, the tadpole of the frog xenopus laevis, and a quiescent, activatable state in a slowly growing adult salamander ambystoma mexicanum, the axolotl. ependymal cells are epithelial in intact spinal cord of all vertebrates. after transection, body region ependymal epithelium in both xenopus and the axolotl disorganizes ...201829535610
morphological and transcriptomic analyses reveal three discrete primary stages of postembryonic development in the common fire salamander, salamandra salamandra.the postembryonic development of amphibians has been characterized as divided into three predominant periods, hereafter named primary developmental stages: premetamorphosis (prem), prometamorphosis (prom), metamorphic climax (meta), and completion of metamorphosis (postm), largely based on examination of anuran development. here, we categorized the postembryonic development of larvae of a poisonous fire salamander (salamandra salamandra) by integrating morphology and gene expression (transcripto ...201829504232
a role for sox9 in post-transcriptional processes: insights from the amphibian oocyte.sox9 is a member of the gene family of sox transcription factors, which is highly conserved among vertebrates. it is involved in different developmental processes including gonadogenesis. in all amniote species examined thus far, sox9 is expressed in the sertoli cells of the male gonad, suggesting an evolutionarily conserved role in testis development. however, in the anamniotes, fishes and amphibians, it is also expressed in the oocyte but the significance of such an expression remains to be el ...201829740094
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
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
high-throughput screening to identify anesthetic ligands using xenopus laevis tadpoles.general anesthetics are considered among the most significant advances in modern medicine; however, they are also some of the most dangerous commonly administered drugs. despite this, the discovery of novel anesthetics has been slow, with few clinically used agents regardless of their nearly 200-year history. xenopus laevis frogs have a long history as a model organism and provide a vital bridge between in vitro and preclinical mammalian assays. the provided protocols are efficient and cost-effe ...201829588028
mitochondrial ros cause motor deficits induced by synaptic inactivity: implications for synapse pruning.developmental synapse pruning refines burgeoning connectomes. the basic mechanisms of mitochondrial reactive oxygen species (ros) production suggest they select inactive synapses for pruning: whether they do so is unknown. to begin to unravel whether mitochondrial ros regulate pruning, we made the local consequences of neuromuscular junction (nmj) pruning detectable as motor deficits by using disparate exogenous and endogenous models to induce synaptic inactivity en masse in developing xenopus l ...201829587245
unexplained cardiac arrest: a tale of conflicting interpretations of kcnq1 genetic test results.unexplained cardiac arrest (uca) is often the first manifestation of an inherited arrhythmogenic disease. genetic testing in uca is challenging due to the complexities of variant interpretation in the absence of supporting cardiac phenotype. we aimed to investigate if a kcnq1 variant [p.(pro64_pro70del)], previously reported as pathogenic, contributes to the long-qt syndrome phenotype, co-segregates with disease or affects kcnq1 function in vitro.201829582136
orthogonality of pyrrolysine trna in the xenopus oocyte.chemical aminoacylation of orthogonal trna allows for the genetic encoding of a wide range of synthetic amino acids without the need to evolve specific aminoacyl-trna synthetases. this method, when paired with protein expression in the xenopus laevis oocyte expression system, can extract atomic scale functional data from a protein structure to advance the study of membrane proteins. the utility of the method depends on the orthogonality of the trna species used to deliver the amino acid. here, w ...201829581437
delay models for the early embryonic cell cycle oscillator.time delays are known to play a crucial role in generating biological oscillations. the early embryonic cell cycle in the frog xenopus laevis is one such example. although various mathematical models of this oscillating system exist, it is not clear how to best model the required time delay. here, we study a simple cell cycle model that produces oscillations due to the presence of an ultrasensitive, time-delayed negative feedback loop. we implement the time delay in three qualitatively different ...201829579091
proteomic characterization of the neural ectoderm fated cell clones in the xenopus laevis embryo by high-resolution mass spectrometry.the molecular program by which embryonic ectoderm is induced to form neural tissue is essential to understanding normal and impaired development of the central nervous system. xenopus has been a powerful vertebrate model in which to elucidate this process. however, abundant vitellogenin (yolk) proteins in cells of the early xenopus embryo interfere with protein detection by high-resolution mass spectrometry (hrms), the technology of choice for identifying these gene products. here, we systematic ...201829578674
the right thalamus may play an important role in anesthesia-awakening regulation in frogs.previous studies have shown that the mammalian thalamus is a key structure for anesthesia-induced unconsciousness and anesthesia-awakening regulation. however, both the dynamic characteristics and probable lateralization of thalamic functioning during anesthesia-awakening regulation are not fully understood, and little is known of the evolutionary basis of the role of the thalamus in anesthesia-awakening regulation.201829576980
incorporation of the δ-subunit into the epithelial sodium channel (enac) generates protease-resistant enacs in xenopus laevis.the epithelial sodium channel (enac) is a critical regulator of vertebrate electrolyte homeostasis. enac is the only constitutively open ion channel in the degenerin/enac protein family, and its expression, membrane abundance, and open probability therefore are tightly controlled. the canonical enac is composed of three subunits (α, β, and γ), but a fourth δ-subunit may replace α and form atypical δβγ-enacs. using xenopus laevis as a model, here we found that mrnas of the α- and δ-subunits are d ...201829576549
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