| nutrient restriction causes reversible g2 arrest in xenopus neural progenitors. | nutrient status affects brain development; however, the effects of nutrient availability on neural progenitor cell proliferation in vivo are poorly understood. without food, xenopus laevis tadpoles enter a period of stasis during which neural progenitor proliferation is drastically reduced, but resumes when food becomes available. here, we investigate how neural progenitors halt cell division in response to nutrient restriction and subsequently re-enter the cell cycle upon feeding. we demonstrat ... | 2019 | 31649012 |
| bioinformatics screening of genes specific for well-regenerating vertebrates reveals c-answer, a regulator of brain development and regeneration. | the molecular basis of higher regenerative capacity of cold-blooded animals comparing to warm-blooded ones is poorly understood. although this difference in regenerative capacities is commonly thought to be a result of restructuring of the same regulatory gene network, we hypothesized that it may be due to loss of some genes essential for regeneration. we describe here a bioinformatic method that allowed us to identify such genes. for investigation in depth we selected one of them encoding trans ... | 2019 | 31644900 |
| azi-medetomidine: synthesis and characterization of a novel α2 adrenergic photoaffinity ligand. | agonists at the α2 adrenergic receptor produce sedation, increase focus, provide analgesia, and induce centrally mediated hypotension and bradycardia, yet neither their dynamic interactions with adrenergic receptors nor their modulation of neuronal circuit activity is completely understood. photoaffinity ligands of α2 adrenergic agonists have the potential both to capture discrete moments of ligand-receptor interactions and to prolong naturalistic drug effects in discrete regions of tissue in vi ... | 2019 | 31638765 |
| nucleoplasmin is a limiting component in the scaling of nuclear size with cytoplasmic volume. | how nuclear size is regulated relative to cell size is a fundamental cell biological question. reductions in both cell and nuclear sizes during xenopus laevis embryogenesis provide a robust scaling system to study mechanisms of nuclear size regulation. to test if the volume of embryonic cytoplasm is limiting for nuclear growth, we encapsulated gastrula-stage embryonic cytoplasm and nuclei in droplets of defined volume using microfluidics. nuclei grew and reached new steady-state sizes as a funct ... | 2019 | 31636119 |
| n-glycosylation of trek-1/hk2p2.1 two-pore-domain potassium (k2p) channels. | mechanosensitive htrek-1 two-pore-domain potassium (hk2p2.1) channels give rise to background currents that control cellular excitability. recently, trek-1 currents have been linked to the regulation of cardiac rhythm as well as to hypertrophy and fibrosis. even though the pharmacological and biophysical characteristics of htrek-1 channels have been widely studied, relatively little is known about their posttranslational modifications. this study aimed to evaluate whether htrek-1 channels are n- ... | 2019 | 31635148 |
| an optimized screen reduces the number of ga transporters and provides insights into nitrate transporter 1/peptide transporter family substrate determinants. | based on recent in vitro data, a relatively large number of the plant nitrate transporter 1/peptide transporter family (npf) proteins have been suggested to function as gibberellic acid (ga) transporters. most ga transporting npf proteins also appear to transport other structurally unrelated phytohormones or metabolites. several of the gas used in previous in vitro assays are membrane permeable weak organic acids whose movement across membranes are influenced by the ph-sensitive ion-trap mechani ... | 2019 | 31632416 |
| kif2a scales meiotic spindle size in hymenochirus boettgeri. | size is a fundamental feature of biological systems that affects physiology at all levels. for example, the dynamic, microtubule-based spindle that mediates chromosome segregation scales to a wide range of cell sizes across different organisms and cell types. xenopus frog species possess a variety of egg and meiotic spindle sizes, and differences in activities or levels of microtubule-associated proteins in the egg cytoplasm between xenopus laevis and xenopus tropicalis have been shown to accoun ... | 2019 | 31630945 |
| biochemical responses revealed in an amphibian species after exposure to a forgotten contaminant: an integrated biomarker assessment. | vanadium is a metal whose toxicity towards terrestrial and aquatic species has been under-reported to date.. the biochemical responses of vanadium in amphibian species have not been determined. to establish the effects of vanadium (v) on exposed adult xenopus laevis, acute and chronic exposures were conducted, and biomarker analyses were performed on liver and muscle tissues from exposed frogs. biomarkers of exposure, such as acetylcholinesterase (ache) and metallothioneins (mt), were analysed. ... | 2020 | 31629886 |
| identification of crucial residues in α-conotoxin ei inhibiting muscle nicotinic acetylcholine receptor. | α-conotoxins (α-ctxs) are small disulfide-rich peptides from venom of conus species that target nicotinic acetylcholine receptors (nachrs). the muscle-type nachrs have been recognized as a potential target for several diseases, such as myogenic disorders, muscle dystrophies, and myasthenia gravis. ei, an α4/7-ctx, mainly blocks α1β1δε nachrs and has an extra n-terminal extension of three amino acids. in this study, the alanine scanning (ala-scan) mutagenesis was applied in order to identify key ... | 2019 | 31623211 |
| popdc3 gene variants associate with a new form of limb girdle muscular dystrophy. | the popeye domain containing 3 (popdc3) gene encodes a membrane protein involved in cyclic adenosine monophosphate (camp) signaling. besides gastric cancer, no disease association has been described. we describe a new muscular dystrophy associated with this gene. | 2019 | 31610034 |
| lin28b increases neural crest cell migration and leads to transformation of trunk sympathoadrenal precursors. | the rna-binding protein lin28b regulates developmental timing and determines stem cell identity by suppressing the let-7 family of micrornas. postembryonic reactivation of lin28b impairs cell commitment to differentiation, prompting their transformation. in this study, we assessed the extent to which ectopic lin28b expression modulates the physiological behavior of neural crest cells (ncc) and governs their transformation in the trunk region of developing embryos. we provide evidence that the ov ... | 2020 | 31601998 |
| embryogenesis of marsupial frogs (hemiphractidae), and the changes that accompany terrestrial development in frogs. | the developmental adaptations of the marsupial frogs gastrotheca riobambae and flectonotus pygmaeus (hemiphractidae) are described and compared with frogs belonging to seven additional families. incubation of embryos by the mother in marsupial frogs is associated with changes in the anatomy and physiology of the female, modifications of oogenesis, and extraordinary changes in embryonic development. the comparison of early development reveals that gene expression is highly conserved. however, the ... | 2019 | 31598865 |
| extracellular lysine 38 plays a crucial role in ph-dependent transport via human monocarboxylate transporter 1. | human monocarboxylate transporters (hmcts) are expressed in many tissues and mediate the transport of various substrates across the plasma membrane. among hmcts, hmct1-4 cotransport h+ with monocarboxylates such as pyruvate and l-lactate, implying that these proteins recognize both substrate and h+. however, the mechanism of translocation, and particularly that of hmct1 ph-dependent transport, remains largely unknown. this study aimed at identifying residues involved in the ph dependence of hmct ... | 2020 | 31593685 |
| cytosolic gaba inhibits anion transport by wheat almt1. | anion transport by aluminium-activated malate transporter (almt) proteins is negatively regulated by gamma-aminobutyric acid (gaba), which increases in concentration during stress. here, the interaction between gaba and wheat (triticum aestivum, ta) taalmt1 heterologously-expressed in xenopus laevis oocytes was investigated. gaba inhibited anion transport by taalmt1 in membrane patches from the cytosolic, not extracellular membrane face, via a reduction in open probability (npopen ), not an inhi ... | 2020 | 31591723 |
| identification of lysine histidine transporter 2 as an 1-aminocyclopropane carboxylic acid transporter in arabidopsis thaliana by transgenic complementation approach. | 1-aminocyclopropane-1-carboxylic acid (acc), a biosynthetic precursor of ethylene, has long been proposed to act as a mobile messenger in higher plants. however, little is known about the transport system of acc. recently, our genetic characterization of an acc-resistant mutant with normal ethylene sensitivity revealed that lysine histidine transporter 1 (lht1) functions as a transporter of acc. as amino acid transporters might have broad substrate specificity, we hypothesized that other amino a ... | 2019 | 31572413 |
| electrophysiological studies revealed cam1-mediated regulation of the arabidopsis calcium channel cngc12. | the arabidopsis cyclic nucleotide-gated channel (cngc) family consists of 20 members, which have been reported to participate in various physiological processes, such as pathogen defense, development, and thermotolerance. although cngc11 and cngc12 have been identified a decade ago and their role in programmed cell death is well studied, their precise channel regulation has not been studied electrophysiologically. here, we determined the channel activities of cngc11 and cngc12 utilizing the two- ... | 2019 | 31572412 |
| in vitro reconstruction of xenopus oocyte ovulation. | progesterone is widely used to induce maturation of isolated fully grown oocytes of the african clawed frog, xenopus laevis. however, the hormone fails to release oocytes from the layer of surrounding follicle cells. here, we report that maturation and follicle rupture can be recapitulated in vitro by treating isolated follicular oocytes with progesterone and low doses of the matrix metalloproteinase (mmp), collagenase, which are ineffective in the absence of the steroid. using this in vitro ovu ... | 2019 | 31561408 |
| bap1 regulates epigenetic switch from pluripotency to differentiation in developmental lineages giving rise to bap1-mutant cancers. | the bap1 tumor suppressor is mutated in many human cancers such as uveal melanoma, leading to poor patient outcome. it remains unclear how bap1 functions in normal biology or how its loss promotes cancer progression. here, we show that bap1 is critical for commitment to ectoderm, mesoderm, and neural crest lineages during xenopus laevis development. bap1 loss causes transcriptional silencing and failure of h3k27ac to accumulate at promoters of key genes regulating pluripotency-to-commitment tran ... | 2019 | 31555735 |
| structural determinants underlying permeant discrimination of the cx43 hemichannel. | connexin (cx) gap junction channels comprise two hemichannels in neighboring cells, and their permeability is well-described, but permeabilities of the single cx hemichannel remain largely unresolved. moreover, determination of isoform-specific cx hemichannel permeability is challenging because of concurrent expression of other channels with similar permeability profiles and inhibitor sensitivities. the mammalian cx hemichannels cx30 and cx43 are gated by extracellular divalent cations, removal ... | 2019 | 31554662 |
| emodepside has sex-dependent immobilizing effects on adult brugia malayi due to a differentially spliced binding pocket in the rck1 region of the slo-1 k channel. | filariae are parasitic nematodes that are transmitted to their definitive host as third-stage larvae by arthropod vectors like mosquitoes. filariae cause diseases including: lymphatic filariasis with distressing and disturbing symptoms like elephantiasis; and river blindness. filarial diseases affect millions of people in 73 countries throughout the topics and sub-tropics. the drugs available for mass drug administration, (ivermectin, albendazole and diethylcarbamazine), are ineffective against ... | 2019 | 31553770 |
| morpholino studies in xenopus brain development. | antisense morpholino oligonucleotides (mos) have become a valuable method to knockdown protein levels, to block with mrna splicing and to interfere with mirna function. mos are widely used to alter gene expression in development of xenopus and zebrafish, where they are typically injected into the fertilized egg or blastomeres. here we present methods to use electroporation to target delivery of mos to the central nervous system of xenopus laevis or xenopus tropicalis tadpoles. briefly, mo electr ... | 2020 | 31552666 |
| odontomas in frogs. | odontomas are variably differentiated, hamartoma-like proliferations of odontogenic epithelium, pulp ectomesenchyme (odontoblasts), and dental matrix. frogs are polyphyodont and homodont. their teeth also differ from mammals in that they are restricted to the upper jaw in adults and lack a periodontal ligament and cementum, attaching directly to the underlying bone. odontomas were identified in an african clawed frog (xenopus laevis), a false tomato frog (dyscophus guineti), and a tomato frog of ... | 2020 | 31551010 |
| exposure to graphene oxide at environmental concentrations induces thyroid endocrine disruption and lipid metabolic disturbance in xenopus laevis. | graphene oxide (go) has become a topic of increasing concern for its environmental and health risks. however, the potential toxic effects of go on wildlife remain limited. the present study chose the xenopus laevis tadpole as a model to assess the thyroid endocrine disruption as well as the lipid metabolic disturbance of go. tadpoles at the 51 stage were exposed to go (0, 0.01, 0.1, and 1 mg/l) for 21 days, when tadpoles were undergoing an extremely complicated phase of morphological changes and ... | 2019 | 31549672 |
| microinjection of dna into eyebuds in xenopus laevis embryos and imaging of gfp expressing optic axonal arbors in intact, living xenopus tadpoles. | the primary visual projection of tadpoles of the aquatic frog xenopus laevis serves as an excellent model system for studying mechanisms that regulate the development of neuronal connectivity. during establishment of the retino-tectal projection, optic axons extend from the eye and navigate through distinct regions of the brain to reach their target tissue, the optic tectum. once optic axons enter the tectum, they elaborate terminal arbors that function to increase the number of synaptic connect ... | 2019 | 31545319 |
| characteristics of in vivo model systems for ovarian cancer studies. | an understanding of the molecular pathogenesis and heterogeneity of ovarian cancer holds promise for the development of early detection strategies and novel, efficient therapies. in this review, we discuss the advantages and limitations of animal models available for basic and preclinical studies. the fruit fly model is suitable mainly for basic research on cellular migration, invasiveness, adhesion, and the epithelial-to-mesenchymal transition. higher-animal models allow to recapitulate the arc ... | 2019 | 31540126 |
| colony-stimulating factor-1- and interleukin-34-derived macrophages differ in their susceptibility to mycobacterium marinum. | mycobacterium tuberculosis (mtb), the causative agent of tuberculosis (tb), remains the leading global cause of death from an infectious agent. mycobacteria thrive within their host mϕs and presently, there is no animal model that permits combined in vitro and in vivo study of mycobacteria-host mϕ interactions. mycobacterium marinum (mm), which causes tb in aquatic vertebrates, has become a promising model for tb research, owing to its close genetic relatedness to mtb and the availability of alt ... | 2019 | 31535730 |
| structure-function elucidation of a new α-conotoxin, milia, from conus milneedwardsi. | the a-conotoxins are peptide toxins that are found in the venom of marine cone snails and they are potent antagonists of various subtypes of nicotinic acetylcholine receptors (nachrs). because nachrs have an important role in regulating transmitter release, cell excitability, and neuronal integration, nachr dysfunctions have been implicated in a variety of severe pathologies. we describe the isolation and characterization of α-conotoxin milia, the first conopeptide from the venom of conus milnee ... | 2019 | 31527432 |
| enrichment of aurora b kinase at the inner kinetochore controls outer kinetochore assembly. | outer kinetochore assembly enables chromosome attachment to microtubules and spindle assembly checkpoint (sac) signaling in mitosis. aurora b kinase controls kinetochore assembly by phosphorylating the mis12 complex (mis12c) subunit dsn1. current models propose dsn1 phosphorylation relieves autoinhibition, allowing mis12c binding to inner kinetochore component cenp-c. using xenopus laevis egg extracts and biochemical reconstitution, we found that autoinhibition of the mis12c by dsn1 impedes its ... | 2019 | 31527147 |
| identification of shaker k+ channel family members in rosaceae and a functional exploration of pbrkat1. | pbrkat1, which is inhibited by external na+ in xenopus laevis oocytes, is characterized as encoding a typical inward rectifying channel that is mainly expressed in guard cells. potassium (k+) is the most abundant cation in plant cells necessary for plant growth and development. the uptake and transport of k+ are mainly completed through transporters and channels, and the shaker family genes are the most studied k+ channels in plants. however, there is far less information about this family in ro ... | 2019 | 31523779 |
| spatiotemporal expression profile of embryonic and adult ankyrin repeat and ef-hand domain containing protein 1-encoding genes ankef1a and ankef1b in zebrafish. | recent human next-generation sequencing (ngs) studies indicate a correlation between ankef1 (ankyrin repeat and ef-hand domain containing protein 1) expression and cilia formation or function. additionally, a single study conducted in the african clawed frog (xenopus laevis) showed ankef1 is down-regulated after pharmacological fibroblast growth factor (fgf) inhibition and plays a role in protocadherin-mediated cell protrusion and adhesion. that study also revealed a critical role for ankef1 in ... | 2019 | 31520739 |
| polyamine biosynthesis in xenopus laevis: the xlazin2/xlodc2 gene encodes a lysine/ornithine decarboxylase. | ornithine decarboxylase (odc) is a key enzyme in the biosynthesis of polyamines, organic cations that are implicated in many cellular processes. the enzyme is regulated at the post-translational level by an unusual system that includes antizymes (azs) and antizyme inhibitors (azins). most studies on this complex regulatory mechanism have been focused on human and rodent cells, showing that azins (azin1 and azin2) are homologues of odc but devoid of enzymatic activity. little is known about xenop ... | 2019 | 31509528 |
| smooth muscle in cardiac chambers is common in turtles and extensive in the emydid turtle, trachemys scripta. | a prominent layer of smooth muscle lining the luminal side of the atria of freshwater turtles (emydidae) was described more than a century ago. we recently demonstrated that this smooth muscle provides a previously unrecognized mechanism to change cardiac output in the emydid red-eared slider (trachemys scripta) that possibly contributes to their tremendous diving capacity. the purpose of the present immunohistochemical study was firstly to screen major groups of vertebrates for the presence of ... | 2020 | 31509333 |
| a herbivore-induced plant volatile of the host plant acts as a collective foraging signal to the larvae of the meadow moth, loxostege sticticalis (lepidoptera: pyralidae). | the meadow moth loxostege sticticalis is a serious agricultural pest that feeds on the leaves of many economic crops, such as sugar beet, soybean, sunflower, and potato. in addition to the rapid migration of adult moths, the collective foraging behavior of the larvae is also thought to be involved in the search for new food sources and substantially contributes to the expansion of the infested area. however, whether and how the chemical signals take part in this process remains unknown. in this ... | 2019 | 31499032 |
| inferring the "primordial immune complex": origins of mhc class i and antigen receptors revealed by comparative genomics. | comparative analyses suggest that the mhc was derived from a prevertebrate "primordial immune complex" (pic). pic duplicated twice in the well-studied two rounds of genome-wide duplications (2r) early in vertebrate evolution, generating four mhc paralogous regions (predominantly on human chromosomes [chr] 1, 6, 9, 19). examining chiefly the amphibian xenopus laevis, but also other vertebrates, we identified their mhc paralogues and mapped mhc class i, agr, and "framework" genes. most class i gen ... | 2019 | 31492741 |
| pharmacological characterization of a homomeric nicotinic acetylcholine receptor formed by ancylostoma caninum acr-16. | parasitic nematode infections are treated using anthelmintic drugs, some of which target nicotinic acetylcholine receptors (nachrs) located in different parasite tissues. the limited arsenal of anthelmintic agents and the prevalence of drug resistance imply that future defense against parasitic infections will depend on the discovery of novel targets and therapeutics. previous studies have suggested that ascaris suum acr-16 nachrs are a suitable target for the development of antinematodal drugs. ... | 2019 | 31486912 |
| disruptive effects of two organotin pesticides on the thyroid signaling pathway in xenopus laevis during metamorphosis. | organotin compounds are the ubiquitous environmental pollutants due to their wide industrial and agricultural applications and unexpected releasing into the environment, which show characteristic of endocrine disruptors to interfere with the synthesis, receptor binding or action of endogenous-hormones. organotin pesticides (otps) are used in agriculture and may impact endocrine functions on organisms. thyroid hormones (ths) play fundamental roles in regulating the basal metabolism and energy bal ... | 2019 | 31476497 |
| disruption of the lotus japonicus transporter ljnpf2.9 increases shoot biomass and nitrate content without affecting symbiotic performances. | after uptake from soil into the root tissue, distribution and allocation of nitrate throughout the whole plant body, is a critical step of nitrogen use efficiency (nue) and for modulation of plant growth in response to various environmental conditions. in legume plants nitrate distribution is also important for the regulation of the nodulation process that allows to fix atmospheric n (n2) through the symbiotic interaction with rhizobia (symbiotic nitrogen fixation, snf). | 2019 | 31470797 |
| comparative analysis of the developmental toxicity in xenopus laevis and danio rerio induced by al2 o3 nanoparticle exposure. | engineered aluminum oxide nanoparticles (al2 o3 nps) having high-grade thermal stability and water-dispersion properties are extensively used in different industries and personal care products. toxicological response evaluation of these nps is indispensable in assessing the health risks and exposure limits because of their industrial disposal into the aquatic environment. we assessed and compared the developmental toxicity of al2 o3 nps in xenopus laevis and danio rerio over a period of 96 h usi ... | 2019 | 31470468 |
| divergent roles of the wnt/pcp formin daam1 in renal ciliogenesis. | kidneys are composed of numerous ciliated epithelial tubules called nephrons. each nephron functions to reabsorb nutrients and concentrate waste products into urine. defects in primary cilia are associated with abnormal formation of nephrons and cyst formation in a wide range of kidney disorders. previous work in xenopus laevis and zebrafish embryos established that loss of components that make up the wnt/pcp pathway, daam1 and arhgef19 (wgef) perturb kidney tubulogenesis. dishevelled, which act ... | 2019 | 31469868 |
| in cell nmr spectroscopy: investigation of g-quadruplex structures inside living xenopus laevis oocytes. | g-quadruplexes are inherently polymorphic nucleic acid structures. their folding topology depends on the nucleic acid primary sequence and on physical-chemical environmental factors. hence, it remains unclear if a g-quadruplex topology determined in the test tube (in vitro) will also form in vivo. characterization of g-quadruplexes in their native environment has been proposed as an efficient strategy to tackle this issue. so far, characterization of g-quadruplex structures in living cells has r ... | 2019 | 31444765 |
| characterization and proteomic-transcriptomic investigation of monocarboxylate transporter 6 knockout mice: evidence of a potential role in glucose and lipid metabolism. | monocarboxylate transporter 6 [(mct6), slc16a5] is an orphan transporter with no known endogenous substrates or physiological role. previous in vitro and in vivo experiments investigated mct6 substrate/inhibitor specificity in xenopus laevis oocytes; however, these data remain limited. transcriptomic changes in the livers of mice undergoing different dieting schemes have suggested that mct6 plays a role in glucose and lipid metabolism. the objectives of this study were 1) to develop a novel knoc ... | 2019 | 31436537 |
| coexposure to environmental concentrations of cis-bifenthrin and graphene oxide: adverse effects on the nervous system during metamorphic development of xenopus laevis. | despite the great concerns associated with the combined biological effects of nanoparticles and insecticides, the current understanding of the corresponding ecological risks remains limited. xenopus laevis (x. laevis) tadpoles were exposed to various concentrations of typical pyrethroid (cis-bifenthrin; cis-bf), either alone or in combination with graphene oxide (go), for 21 days. the presence of go resulted in increased bioconcentration of cis-bf and a higher 1s-enantiomer fraction. exposure to ... | 2020 | 31425913 |
| xenopus laevis as a bioindicator of endocrine disruptors in the region of central chile. | one of the direct causes of biodiversity loss is environmental pollution resulting from the use of chemicals. different kinds of chemicals, such as persistent organic pollutants and some heavy metals, can be endocrine disruptors, which act at low doses over a long period of time and have a negative effect on the reproductive and thyroid system in vertebrates worldwide. research on the effects of endocrine disruptors and the use of bioindicators in neotropical ecosystems where pressure on biodive ... | 2019 | 31422435 |
| changes in ca2+ removal can mask the effects of geometry during ip3r mediated ca2+ signals. | calcium (ca2+) signals are ubiquitous. most intracellular ca2+ signals involve the release of ca2+ from the endoplasmic reticulum (er) through inositol 1,4,5-trisphosphate receptors (ip3rs). the non-uniform spatial organization of ip3rs and the fact that their individual openings are coupled via cytosolic ca2+ are key factors for the variety of spatio-temporal distributions of the cytosolic [ca2+] and the versatility of the signals. in this paper we combine experiments performed in untreated and ... | 2019 | 31417423 |
| gaining insights in the nutritional metabolism of amphibians: analyzing body nutrient profiles of the african clawed frog, xenopus laevis. | whole bodies of xenopus laevis (n = 19) were analysed for chemical composition and morphometrics. the nutrient profile (macronutrients, amino acids, fatty acids and minerals) was evaluated by sex; interactions among variables with body weights and lengths, and comparisons made with different species of marine and fresh water fish. significant differences were found in morphometric measurements, water content, several minerals and fatty acids between sexes of x. laevis. amino acid profiles differ ... | 2019 | 31410305 |
| novel vectors for functional interrogation of xenopus orfeome coding sequences. | the current xenopus orfeome contains ~10,250 validated, full-length cdna sequences without stop codons from xenopus laevis and ~3,970 from xenopus tropicalis cloned into gateway-compatible entry vectors. to increase the utility of the orfeome, we have constructed the gateway-compatible destination vectors pdxtp and pdxtr, which in combination can control the spatial and temporal expression of any open reading frame (orf). pdxtp receives a promoter/enhancer of interest, which controls the spatial ... | 2019 | 31403250 |
| comparative embryonic spatio-temporal expression profile map of the xenopus p2x receptor family. | p2x receptors are atp-gated cations channels formed by the homo or hetero-trimeric association from the seven cloned subunits (p2x1-7). p2x receptors are widely distributed in different organs and cell types throughout the body including the nervous system and are involved in a large variety of physiological but also pathological processes in adult mammals. however, their expression and function during embryogenesis remain poorly understood. here, we report the cloning and the comparative expres ... | 2019 | 31402854 |
| radiographic and ultrasonographic appearance of pneumonia in a frog. | a 12-year-old female african clawed frog (xenopus laevis) displayed lethargy and anorexia for 1 week. radiographs detected a moderately reduced volume of aerated lung with lobulated margins with the left lung predominantly affected. transcelomic ultrasound revealed marked consolidation of the left lung. postmortem examination confirmed suppurative and histiocytic pneumonia, worse in the left lung, caused by mycobacterium chelonae. given that amphibian pulmonary consolidation and celomic effusion ... | 2019 | 31392794 |
| evolution of cis-regulatory modules for the head organizer gene goosecoid in chordates: comparisons between branchiostoma and xenopus. | in cephalochordates (amphioxus), the notochord runs along the dorsal to the anterior tip of the body. in contrast, the vertebrate head is formed anterior to the notochord, as a result of head organizer formation in anterior mesoderm during early development. a key gene for the vertebrate head organizer, goosecoid (gsc), is broadly expressed in the dorsal mesoderm of amphioxus gastrula. amphioxus gsc expression subsequently becomes restricted to the posterior notochord from the early neurula. thi ... | 2019 | 31388442 |
| stereoselective anti-cancer activities of ginsenoside rg3 on triple negative breast cancer cell models. | ginsenoside rg3 (rg3) has two epimers, 20(s)-ginsenoside rg3 (srg3) and 20(r)-ginsenoside rg3 (rrg3), and while rg3 itself has been reported to have anti-cancer properties, few studies have been reported on the anti-cancer effects of the different epimers. the aim was to investigate the stereoselective effects of the rg3 epimers on triple negative breast cancer (tnbc) cell lines, tested using cell-based assays for proliferation, apoptosis, cell cycle arrest, migration and invasion. molecular doc ... | 2019 | 31374984 |
| allocation trade-offs impact organ size and muscle architecture in an invasive population of xenopus laevis in western france. | invasive species are a global scourge and often negatively impact native species. understanding the expansion and dispersal limits of these species is essential. as previous studies have demonstrated increased locomotor performance for populations at the edge of the range of expanding populations, studies of locomotion including the anatomical and physiological traits underlying dispersal capacity are of interest. we focus here on an invasive population of xenopus laevis introduced in france nea ... | 2019 | 31373390 |
| leishmania heme uptake involves lmflvcrb, a novel porphyrin transporter essential for the parasite. | leishmaniasis comprises a group of neglected diseases caused by the protozoan parasite leishmania spp. as is the case for other trypanosomatid parasites, leishmania is auxotrophic for heme and must scavenge this essential compound from its human host. in mammals, the slc transporter flvcr2 mediates heme import across the plasma membrane. herein we identify and characterize leishmania major flvcrb (lmflvcrb), the first member of the flvcr family studied in a non-metazoan organism. this protein lo ... | 2020 | 31372684 |
| erratum: skin grafting in xenopus laevis: a technique for assessing development and immunological disparity. | | 2019 | 31371466 |
| jmjd6a regulates gsk3β rna splicing in xenopus laevis eye development. | it has been suggested that jmjd6 plays an important role in gene regulation through its demethylation or hydroxylation activity on histone and transcription factors. in addition, jmjd6 has been shown to regulate rna splicing by interaction with splicing factors. in this study, we demonstrated that jmjd6a is expressed in developing xenopus laevis eye during optic vesicle formation and retinal layer differentiation stages. knockdown of jmjd6a by an antisense morpholino resulted in eye malformation ... | 2019 | 31361752 |
| identification of the catechin uptake transporter responsible for intestinal absorption of epigallocatechin gallate in mice. | many studies have shown that epigallocatechin gallate (egcg) contribute to the health benefits of green tea, although its bioavailability is usually low. however, the mechanism underlying its intestinal absorption remains unclear. in human subjects, it has been reported that the bioavailability of egcg increases after repeated oral catechin intake. we hypothesized that a certain uptake transporter was involved in this increase, and investigated a novel egcg transporter. we first confirmed the in ... | 2019 | 31358798 |
| maldi-imaging of early stage xenopus laevis embryos. | xenopus laevis is an important model organism for vertebrate development. an extensive literature has developed on changes in transcript expression during development of this organism, and there is a growing literature on the corresponding protein expression changes during development. in contrast, there is very little information on changes in metabolite expression during development. we present the first maldi mass-spectrometry images of metabolites within the developing embryo. these images w ... | 2019 | 31357275 |
| encephalopathies with kcnc1 variants: genotype-phenotype-functional correlations. | to analyze clinical phenotypes associated with kcnc1 variants other than the progressive myoclonus epilepsy-causing variant p.arg320his, determine the electrophysiological functional impact of identified variants and explore genotype-phenotype-physiological correlations. | 2019 | 31353855 |
| spatial analysis of reck, mt1-mmp, and timp-2 proteins during early xenopus laevis development. | proper cell-cell and cell-ecm interactions are vital for cell migration and patterning of the vertebrate embryo. mmps and their inhibitors, reck and timps, are all differentially expressed during embryogenesis to regulate such ecm remodeling and cell interactions. mt1-mmp, reck, and timp-2 are unique amongst other ecm-regulating proteins as they act in the pericellular space. past studies have shown that reck and timp-2 interact with mt1-mmp on the cell surface, thereby influencing cell behaviou ... | 2019 | 31352120 |
| sorafenib activity and disposition in liver cancer does not depend on organic cation transporter 1. | systemic therapy of advanced hepatocellular carcinoma (hcc) with the small-molecule multikinase inhibitor sorafenib is associated with large interindividual pharmacokinetic variability and unpredictable side effects potentially requiring dose reduction or treatment termination. organic cation transporter (oct1; gene slc22a1) has been proposed as a clinical biomarker of hcc response. because proof is lacking that oct1 transports sorafenib, we used a combinatorial approach to define how oct1 contr ... | 2020 | 31350763 |
| αd-conotoxins in species of the eastern pacific: the case of conus princeps from mexico. | conus snails produce venoms containing numerous peptides such as the α-conotoxins (α-ctxs), which are well-known nicotinic acetylcholine receptor (nachr) antagonists. thirty-eight chromatographic fractions from conus princeps venom extract were isolated by rp-hplc. the biological activities of 37 fractions (0.07 µg/µl) were assayed by two-electrode voltage clamp on human α7 nachrs expressed in xenopus laevis oocytes. fractions f7 and f16 notably inhibited the response elicited by acetylcholine b ... | 2019 | 31336928 |
| reference gene validation for quantitative real-time pcr studies in amphibian kidney-derived a6 epithelial cells. | quantitative real-time polymerase chain reaction is a widely used technique that relies on reference genes for the normalisation of gene expression. these reference genes are constitutively expressed and must remain stable across all samples and treatments. stability of housekeeping genes may vary and must be optimised for a specific tissue, sample or cell line. here we present a study screening for possible reference gene candidates, eef1a1, rpl8, sub1.l, clta, h4 and odc1, in the xenopus laevi ... | 2019 | 31333044 |
| involvement of g-quadruplex regions in mammalian replication origin activity. | genome-wide studies of dna replication origins revealed that origins preferentially associate with an origin g-rich repeated element (ogre), potentially forming g-quadruplexes (g4). here, we functionally address their requirements for dna replication initiation in a series of independent approaches. deletion of the ogre/g4 sequence strongly decreased the corresponding origin activity. conversely, the insertion of an ogre/g4 element created a new replication origin. this element also promoted rep ... | 2019 | 31332171 |
| na3 glycan: a potential therapy for retinal pigment epithelial deficiency. | atrophic age-related macular degeneration (amd) is the most common type of amd, yet there is no united states food and drug administration (fda)-approved therapy. this disease is characterized by retinal pigment epithelial (rpe) insufficiency, primarily in the macula, which affects the structure and physiology of photoreceptors and ultimately, visual function. in this study, we evaluated the protective effects of a naturally derived small molecule glycan therapeutic-asialo-, tri-antennary comple ... | 2019 | 31322324 |
| structure, development, and functional morphology of the cement gland of the giant danio, devario malabaricus. | aquatic species in several clades possess cement glands producing adhesive secretions of various strengths. in vertebrates, transient adhesive organs have been extensively studied in xenopus laevis, other anurans, and in several fish species. however, the development of these structures is not fully understood. | 2019 | 31310039 |
| evaluating the role of fish as surrogates for amphibians in pesticide ecological risk assessment. | ecological risk of chemicals to aquatic-phase amphibians has historically been evaluated by comparing estimated environmental concentrations in surface water to surrogate toxicity data from fish species. despite their obvious similarities, there are biological disparities among fish and amphibians that could affect their exposure and response to chemicals. given the alarming decline in amphibians, in which anthropogenic pollutants play at least some role, investigating the risk of chemicals to a ... | 2019 | 31299708 |
| the many faces of xenopus: xenopus laevis as a model system to study wolf-hirschhorn syndrome. | wolf-hirschhorn syndrome (whs) is a rare developmental disorder characterized by intellectual disability and various physical malformations including craniofacial, skeletal, and cardiac defects. these phenotypes, as they involve structures that are derived from the cranial neural crest, suggest that whs may be associated with abnormalities in neural crest cell (ncc) migration. this syndrome is linked with assorted mutations on the short arm of chromosome 4, most notably the microdeletion of a cr ... | 2019 | 31297068 |
| phosphomimetic substitution at ser-33 of the chloroquine resistance transporter pfcrt reconstitutes drug responses in plasmodium falciparum. | the chloroquine resistance transporter pfcrt of the human malaria parasite plasmodium falciparum confers resistance to the former first-line antimalarial drug chloroquine, and it modulates the responsiveness to a wide range of quinoline and quinoline-like compounds. pfcrt is post-translationally modified by phosphorylation, palmitoylation, and, possibly, ubiquitination. however, the impact of these post-translational modifications on p. falciparum biology and, in particular, the drug resistance- ... | 2019 | 31285265 |
| assessing predator-prey interactions in a chemically altered aquatic environment: the effects of ddt on xenopus laevis and culex sp. larvae interactions and behaviour. | behavioural assays are used as a tool to understand ecotoxicological effects on organisms, but are often not applied in an ecologically relevant context. assessment of the effect of chemical contaminants on behaviours relating to fitness and trophic interactions for example, requires incorporating predator-prey interactions to create impact assessments. dichlorodiphenyltrichloroethane (ddt) is a controlled substance but is still regularly used as a form of mosquito control. there is little expli ... | 2019 | 31278447 |
| effects of cis-bifenthrin enantiomers on the growth, behavioral, biomarkers of oxidative damage and bioaccumulation in xenopus laevis. | chirality should be taken into consideration when assessing the effect of synthetic pyrethroids to aquatic environmental safety. in our study, 96 h acute toxicity assay showed that enantiomers of cis-bf had an addictive effect of toxicity on xenopus laevis and r-cis-bifenthrin(r-cis-bf) had higher acute toxicity than s-cis-bf. in chronic assay, r-cis-bf exerted more toxic effect on behavior and development of tadpoles than s-cis-bf, and there was also enantioselective effect of cis-bf on antioxi ... | 2019 | 31276910 |
| neuroendocrine modulation of predator avoidance/prey capture tradeoffs: role of tectal npy2r receptors. | the optic tectum rapidly inhibits food intake when a visual threat is present. anatomical and electrophysiological evidence support a role for neuropeptide y (npy), originating from cells in the thalamus, in the tectal inhibition of prey capture. here we test the hypothesis that tectal npy receptor type 2 (npy2r) influences prey-capture and predator-avoidance responses in the african clawed frog, xenopus laevis. we tested two questions: 1) does tectal npy administration decrease food intake and ... | 2019 | 31271760 |
| impact of 4-aminopyridine on vestibulo-ocular reflex performance. | vestibulo-ocular reflexes (vor) are mediated by frequency-tuned pathways that separately transform the different dynamic and static aspects of head motion/position-related sensory signals into extraocular motor commands. voltage-dependent potassium conductances such as those formed by kv1.1 are important for the ability of vor circuit elements to encode highly transient motion components. here we describe the impact of the kv1.1 channel blocker 4-aminopyridine (4-ap) on spontaneous and motion-ev ... | 2019 | 31270663 |
| impacts of the synthetic androgen trenbolone on gonad differentiation and development - comparisons between three deeply diverged anuran families. | using a recently developed approach for testing endocrine disruptive chemicals (edcs) in amphibians, comprising synchronized tadpole exposure plus genetic and histological sexing of metamorphs in a flow-through-system, we tested the effects of 17β-trenbolone (tb), a widely used growth promoter in cattle farming, in three deeply diverged anuran families: the amphibian model species xenopus laevis (pipidae) and the non-models bufo(tes) viridis (bufonidae) and hyla arborea (hylidae). trenbolone was ... | 2019 | 31270347 |
| developmentally regulated gtp-binding protein 1 modulates ciliogenesis via an interaction with dishevelled. | cilia are critical for proper embryonic development and maintaining homeostasis. although extensively studied, there are still significant gaps regarding the proteins involved in regulating ciliogenesis. using the xenopus laevis embryo, we show that dishevelled (dvl), a key wnt signaling scaffold that is critical to proper ciliogenesis, interacts with drg1 (developmentally regulated gtp-binding protein 1). the loss of drg1 or disruption of the interaction with dvl reduces the length and number o ... | 2019 | 31270137 |
| phosphatidylinositol 4,5-bisphosphate (pip2) and ca2+ are both required to open the cl- channel tmem16a. | transmembrane member 16a (tmem16a) is a widely expressed ca2+-activated cl- channel with various physiological functions ranging from mucosal secretion to regulating smooth muscle contraction. understanding how tmem16a controls these physiological processes and how its dysregulation may cause disease requires a detailed understanding of how cellular processes and second messengers alter tmem16a channel gating. here we assessed the regulation of tmem16a gating by recording ca2+-evoked cl- current ... | 2019 | 31266809 |
| dyrk1a-related intellectual disability: a syndrome associated with congenital anomalies of the kidney and urinary tract. | haploinsufficiency of dyrk1a causes a recognizable clinical syndrome. the goal of this paper is to investigate congenital anomalies of the kidney and urinary tract (cakut) and genital defects (gd) in patients with dyrk1a variants. | 2019 | 31263215 |
| functional characterization of smn evolution in mouse models of sma. | spinal muscular atrophy (sma) is a monogenic neurodegenerative disorder and the leading genetic cause of infantile mortality. while several functions have been ascribed to the smn (survival motor neuron) protein, their specific contribution to the disease has yet to be fully elucidated. we hypothesized that some, but not all, smn homologues would rescue the sma phenotype in mouse models, thereby identifying disease-relevant domains. using aav9 to deliver smn homologs to sma mice, we identified a ... | 2019 | 31263170 |
| comparative analysis of p4ha1 and p4ha2 expression during xenopus laevis development. | collagen prolyl 4-hydroxylases (c-p4hs) are evolutionary conserved enzymes whose activity is essential for the correct folding of stable triple helical molecules of collagen and collagen-like proteins. they play crucial roles in embryo development, connective tissue functional organization, tumor growth and metastasis. despite the important function of these enzymes, little is known about their expression during vertebrate development. in this study, we determine and compare the previously undes ... | 2019 | 31250915 |
| transcriptome analysis of regeneration during xenopus laevis experimental twinning. | animal embryos have the remarkable property of self-organization. over 125 years ago, hans driesch separated the two blastomeres of sea urchin embryos and obtained twins, in what was the foundation of experimental embryology. since then, embryonic twinning has been obtained experimentally in many animals. in a recent study, we developed bisection methods that generate identical twins reliably from xenopus blastula embryos. in the present study, we have investigated the transcriptome of regenerat ... | 2019 | 31250914 |
| data demonstrating distinct embryonic developmental defects induced by bisphenol a alternatives. | embryos of xenopus laevis (african clawed frog) were exposed to the widespread environmental plasticizers bisphenol af (bpaf; 0.003-3 μm), bisphenol a (bpa; 1-50 μm), or 17β-estradiol (e2; 10 μm) from just after fertilization through 96 hours of development. the potencies and cellular and morphological effects were compared across chemical treatments and controls. the embryos were staged, counted and imaged, and time-lapse movies collected, on an inverted stereomicroscope and camera. the data sh ... | 2019 | 31249853 |
| an extracellular acidic cleft confers profound h+-sensitivity to epithelial sodium channels containing the δ-subunit in xenopus laevis. | the limited sodium availability of freshwater and terrestrial environments was a major physiological challenge during vertebrate evolution. the epithelial sodium channel (enac) is present in the apical membrane of sodium-absorbing vertebrate epithelia and evolved as part of a machinery for efficient sodium conservation. enac belongs to the degenerin/enac protein family and is the only member that opens without an external stimulus. we hypothesized that enac evolved from a proton-activated sodium ... | 2019 | 31248986 |
| commentary on classic paper "gimlich, r.l., gerhart, j.c., 1984. early cellular interactions promote embryonic axis formation in xenopus laevis. dev biol 104, 117-130." | | 2019 | 31235010 |
| catalyst-free click pegylation reveals substantial mitochondrial atp synthase sub-unit alpha oxidation before and after fertilisation. | using non-reducing western blotting to assess protein thiol redox state is challenging because most reduced and oxidised forms migrate at the same molecular weight and are, therefore, indistinguishable. while copper catalysed click chemistry can be used to ligate a polyethylene glycol (peg) moiety termed click pegylation to mass shift the reduced or oxidised form as desired, the potential for copper catalysed auto-oxidation is problematic. here we define a catalyst-free trans-cyclooctene-methylt ... | 2019 | 31234016 |
| cardiotoxicity in african clawed frog (xenopus laevis) sub-chronically exposed to environmentally relevant atrazine concentrations: implications for species survival. | the toxic effects of different atrazine concentrations on tadpoles and adult male african clawed frogs (xenopus laevis) were assessed in a controlled laboratory environment following 90 days' exposure. the aim was to elucidate the danger of atrazine exposure on the cardiac tissue relative to its critical function of rhythmic contractility, fundamental for optimal blood circulation and homeostasis. tadpoles and adult frogs were exposed to 0 μg/l (control), 0.01 μg l-1, 200 μg l-1 and 500 μg l-1 c ... | 2019 | 31203168 |
| peia-5466: a novel peptide antagonist containing non-natural amino acids that selectively targets α3β2 nicotinic acetylcholine receptors. | pharmacologically distinguishing α3β2 nicotinic acetylcholine receptors (nachrs) from closely related subtypes, particularly α6β2, has been challenging due to the lack of subtype-selective ligands. we created analogs of α-conotoxin (α-ctx) peia to identify ligand-receptor interactions that could be exploited to selectively increase potency and selectivity for α3β2 nachrs. a series of peia analogs were synthesized by replacing amino acid residues in the second disulfide loop with standard or nons ... | 2019 | 31194549 |
| single cell proteomics by data-independent acquisition to study embryonic asymmetry in xenopus laevis. | techniques that allow single cell analysis are gaining widespread attention, and most of these studies utilize genomics-based approaches. while nanofluidic technologies have enabled mass spectrometric analysis of single cells, these measurements have been limited to metabolomics and lipidomic studies. single cell proteomics has the potential to improve our understanding of intercellular heterogeneity. however, this approach has faced challenges including limited sample availability, as well as a ... | 2019 | 31194517 |
| injection of mrna isolated from trophozoites of giardia intestinalis induces expression of three types of chloride currents in xenopus laevis oocytes. | giardia lamblia is one of the most important worldwide causes of intestinal infections, yet little is known about its cellular physiology, especially the diversity of ionic channels that this parasite expresses. in this work, we show that injection of mrna isolated from trophozoites of giardia, into xenopus laevis oocytes, induces expression of three types of chloride currents (here referred to as icl-g1, icl-g2, and icl-g3), which have different biophysical and pharmacological properties. icl-g ... | 2019 | 31187589 |
| the effect of xenopus laevis egg extracts with/without brg1 on the development of preimplantation cloned mouse embryos. | summarymuch effort has been devoted to improving the efficiency of animal cloning. the aim of this study was to investigate the effect of brg1 contained in xenopus egg extracts on the development of cloned mouse embryos. the results showed that mouse nih/3t3 cells were able to express pluripotent genes after treatment with egg extracts, indicating that the egg extracts contained reprogramming factors. after co-injection of xenopus egg extracts and single mouse cumulus cells into enucleated mouse ... | 2019 | 31182178 |
| dspe-peg modification of α-conotoxin txid. | in order to improve stability of a peptide marine drug lead, α-conotoxin txid, we synthesized and modified txid at the n-terminal with dspe-peg-nhs by a nucleophilic substitution reaction to prepare the dspe-peg-txid for the first time. the reaction conditions, including solvent, ratio, ph, and reaction time, were optimized systematically and the optimal one was reacted in dimethyl formamide at ph 8.2 with triethylamine at room temperature for 120 h. the in vitro stabilities in serum, simulated ... | 2019 | 31181805 |
| ecotoxicity of nanomaterials in amphibians: a critical review. | nanomaterials (nms) have been used in a growing number of commercial products, and their rapid expansion could lead to their release into the aquatic environments. however, there is limited knowledge about the impact of nms in the biota, especially the amphibians. the present study revised the historical use of amphibian species as a model system for nanoecotoxicological studies and summarized the data available in the scientific literature about the genotoxic, mutagenic, histopathological, embr ... | 2019 | 31181520 |
| disassembly of actin and keratin networks by aurora b kinase at the midplane of cleaving xenopus laevis eggs. | the large length scale of xenopus laevis eggs facilitates observation of bulk cytoplasm dynamics far from the cortex during cytokinesis. the first furrow ingresses through the egg midplane, which is demarcated by chromosomal passenger complex (cpc) localized on microtubule bundles at the boundary between asters. using an extract system, we found that local kinase activity of the aurora b kinase (aurkb) subunit of the cpc caused disassembly of f-actin and keratin between asters and local softenin ... | 2019 | 31178324 |
| organic anion-transporting polypeptide 1a4-mediated heterogeneous distribution of sulforhodamine-101 in rat hepatic lobules. | it has been known that organic anion-transporting polypeptides (oatps) involve hepatic transports several organic anionic compounds and drugs. this study aimed to investigate sulforhodamine-101 (sr-101) distribution in the rat liver, determine the molecules responsible for the distribution, and delineate the manner of distribution. after intravenous sr-101 administration, its distribution in frozen rat hepatic sections was examined. sr-101-derived signals were detected in regions around the hepa ... | 2019 | 31174976 |
| a sclerocornea-associated rad21 variant induces corneal stroma disorganization. | sclerocornea is a cornea opacification disorder. disorganized corneal stroma fibrils are observed in patients' cornea. previously we identified a rad21c1348t variant that is associated with a peripheral sclerocornea pedigree. to explore whether this rad21 variant can induce sclerocornea-related phenotype, and to investigate the possible mechanisms of such phenotype, the orthologous rad21 wild-type and variant mrnas were injected into xenopus laevis embryos and the developed eyes were subjected f ... | 2019 | 31173765 |
| ism1 regulates nodal signaling and asymmetric organ morphogenesis during development. | isthmin1 (ism1) was originally identified as a fibroblast group factor expressed in xenopus laevis embryonic brain, but its biological functions remain unclear. the spatiotemporal distribution of ism1, with high expression in the anterior primitive streak of the chick embryo and the anterior mesendoderm of the mouse embryo, suggested that ism1 may regulate signaling by the nodal subfamily of tgb-β cytokines that control embryo patterning. we report that ism1 is an inhibitor of nodal signaling. i ... | 2019 | 31171630 |
| mortality, teratogenicity and growth inhibition of three glyphosate formulations using frog embryo teratogenesis assay-xenopus. | ample evidence around the world exists suggesting a link between exposure to glyphosate, toxicity and perturbed physiological functions in non-target organisms. although glyphosate formulations are widely used for weed and alien plant management, their ecotoxicological information remain scanty. using the 96-hour frog embryo teratogenesis assay-xenopus protocol, embryotoxicity and teratogenicity of three glyphosate-based formulations were assessed. embryos of xenopus laevis were exposed to round ... | 2019 | 31168868 |
| impacts of the mhc class i-like xnc10 and innate-like t cells on tumor tolerance and rejection in the amphibian xenopus. | the conditions that lead to antitumor or protumor functions of natural killer t (nkt) cells against mammalian tumors are only partially understood. therefore, insights into the evolutionary conservation of nkt and their analogs-innate-like t (it) cells-may reveal factors that contribute to tumor eradication. as such, we investigated the amphibian xenopus laevis it cells and interacting mhc class i-like (xnc or mhc1b.l) genes against ff-2 thymic lymphoid tumors. upon ff-2 intraperitoneal transpla ... | 2019 | 31155639 |
| the direct permeation of nanoparticles through the plasma membrane transiently modifies its properties. | the exposure to metal nanoparticles (nps) has increased with their widespread use in industry, research and medicine. it is well known that nps may enter cells and that this mechanism is crucial to exert both the therapeutic and toxicity effects. the main cellular entrance route is endocytosis-based, however, recent experimental studies, have reported that nps can also enter the cell crossing directly the plasma membrane, it is thus important to investigate this alternative internalization mecha ... | 2019 | 31150635 |
| the plus maze and scototaxis test are not valid behavioral assays for anxiety assessment in the south african clawed frog. | there are no behavioral models for testing anxiety in amphibians, a group of animals widely used for developmental, ecotoxicological, and genetic research. we aimed to validate two common rodent paradigms, the plus maze and the scototaxis test, for use in the aquatic african clawed frog (xenopus laevis). we predicted: (a) that frogs would prefer the dark, vs. light, portions of the testing arenas (face validity), (b) that this behavior could be altered with acute administration of anxio-selectiv ... | 2019 | 31144017 |
| acclimation temperature effects on locomotor traits in adult aquatic anurans (x. tropicalis and x. laevis) from different latitudes: possible implications for climate change. | climate change is in part responsible for the 70% decline in amphibian species numbers worldwide. although temperature is expected to impact whole-organism performance in ectotherms, reversible thermal acclimation has been suggested as a mechanism that may buffer responses to abrupt temperature changes. here, we test for an effect of acclimation on locomotor performance traits (jump force and stamina) in adults of two predominantly aquatic and closely related frog species from different climatic ... | 2019 | 31139411 |
| using the xenopus developmental eye regrowth system to distinguish the role of developmental versus regenerative mechanisms. | a longstanding challenge in regeneration biology is to understand the role of developmental mechanisms in restoring lost or damaged tissues and organs. as these body structures were built during embryogenesis, it is not surprising that a number of developmental mechanisms are also active during regeneration. however, it remains unclear whether developmental mechanisms act similarly or differently during regeneration as compared to development. since regeneration is studied in the context of matu ... | 2019 | 31139088 |
| preserving genome integrity during the early embryonic dna replication cycles. | during the very early stages of embryonic development chromosome replication occurs under rather challenging conditions, including a very short cell cycle, absence of transcription, a relaxed dna damage response and, in certain animal species, a highly contracted s-phase. this raises the puzzling question of how the genome can be faithfully replicated in such a peculiar metabolic context. recent studies have provided new insights into this issue, and unveiled that embryos are prone to accumulate ... | 2019 | 31137726 |