| phosphorylation influences water and ion channel function of atpip2;1. | the phosphorylation state of two serine residues within the c-terminal domain of atpip2;1 (s280, s283) regulates its plasma membrane localization in response to salt and osmotic stress. here, we investigated whether the phosphorylation state of s280 and s283 also influence atpip2;1 facilitated water and cation transport. a series of single and double s280 and s283 phosphomimic and phosphonull atpip2;1 mutants were tested in heterologous systems. in xenopus laevis oocytes, phosphomimic mutants at ... | 2020 | 32678928 |
| predation threats for a 24-h period activated the extension of axons in the brains of xenopus tadpoles. | the threat of predation is a driving force in the evolution of animals. we have previously reported that xenopus laevis enhanced their tail muscles and increased their swimming speeds in the presence of japanese larval salamander predators. herein, we investigated the induced gene expression changes in the brains of tadpoles under the threat of predation using 3'-tag digital gene expression profiling. we found that many muscle genes were expressed after 24 h of exposure to predation. ingenuity p ... | 2020 | 32678123 |
| electrophysiological effects of non-vitamin k antagonist oral anticoagulants on atrial repolarizing potassium channels. | non-vitamin k antagonist oral anticoagulants (noacs) are widely used in the prevention of stroke and systemic embolism in patients with non-valvular atrial fibrillation (af). the efficacy of noacs has been attributed in part to pleiotropic effects that are mediated through effects on thrombin, factor xa, and their respective receptors. direct pharmacological effects of noacs and cardiac ion channels have not been addressed to date. we hypothesized that the favourable clinical outcome of noac use ... | 2020 | 32676673 |
| functional and regulatory characterization of three amts in maize roots. | maize grows in nitrate-dominated dryland soils, but shortly upon localized dressing of nitrogen fertilizers, ammonium is retained as a noticeable form of nitrogen source available to roots. thus in addition to nitrate, the absorption of ammonium can be an important strategy that promotes rapid plant growth at strong nitrogen demanding stages. the present study reports the functional characterization of three root-expressed ammonium transporters (amts), aiming at finding out functional and regula ... | 2020 | 32676086 |
| mechanosensitivity is an essential component of phototransduction in vertebrate rods. | photoreceptors are specialized cells devoted to the transduction of the incoming visual signals. rods are able also to shed from their tip old disks and to synthesize at the base of the outer segment (os) new disks. by combining electrophysiology, optical tweezers (ots), and biochemistry, we investigate mechanosensitivity in the rods of xenopus laevis, and we show that 1) mechanosensitive channels (mscs), transient receptor potential canonical 1 (trpc1), and piezo1 are present in rod inner segme ... | 2020 | 32667916 |
| role of taalmt1 malate-gaba transporter in alkaline ph tolerance of wheat. | malate exudation through wheat (triticum aestivum l) aluminium-activated malate transporter 1 (taalmt1) confers al3+ tolerance at low ph, but is also activated by alkaline ph, and is regulated by and facilitates significant transport of gamma-aminobutyric acid (gaba, a zwitterionic buffer). therefore, taalmt1 may facilitate acidification of an alkaline rhizosphere by promoting exudation of both malate and gaba. here, the performance of wheat near isogenic lines et8 (al+3 -tolerant, high taalmt1 ... | 2020 | 32666573 |
| slc12a2 variants cause a neurodevelopmental disorder or cochleovestibular defect. | the slc12 gene family consists of slc12a1-slc12a9, encoding electroneutral cation-coupled chloride co-transporters. scl12a2 has been shown to play a role in corticogenesis and therefore represents a strong candidate neurodevelopmental disorder gene. through trio exome sequencing we identified de novo mutations in slc12a2 in six children with neurodevelopmental disorders. all had developmental delay or intellectual disability ranging from mild to severe. two had sensorineural deafness. we also id ... | 2020 | 32658972 |
| oxidized glutathione increases delta-subunit expressing epithelial sodium channel activity in xenopus laevis oocytes. | epithelial sodium channels (enac) are heterotrimeric structures, made up of α, β, and γ subunits, and play an important role in maintaining fluid homeostasis. when δ-enac subunits are expressed in place of (or in addition to) the α-enac subunit alongside β- and γ- subunits, fundamental changes in the biophysical properties of enac can be observed. using human enac crna constructs and the xenopas laevis oocyte expression system, we show that oxidized glutathione (gssg) differently effects αβγ-ena ... | 2020 | 32656545 |
| mambalgin-2 induces cell cycle arrest and apoptosis in glioma cells via interaction with asic1a. | gliomas are fast growing and highly invasive brain tumors, characterized by tumor microenvironment acidification that drives glioma cell growth and migration. channels containing acid-sensing ion channel 1a subunit (asic1a) mediate amiloride-sensitive cation influx in late stage glioma cells, but not in normal astrocytes. thus, selective targeting of asic1a can be a perspective strategy for glioma treatment. here, asic1a expression in u251 mg and a172 glioma cells, but not in normal astrocytes, ... | 2020 | 32650495 |
| transcriptomic analysis identifies early cellular and molecular events by which estrogen disrupts testis differentiation and causes feminization in xenopus laevis. | extensive studies have shown that estrogenic endocrine-disrupting chemicals (edcs) can disrupt testis differentiation and even cause feminization in vertebrates. however, little is known about the mechanisms by which estrogenic edcs disrupt testis differentiation. here, we employed xenopus laevis, a model amphibian species sensitive to estrogenic edcs, to explore the molecular and cellular events by which 17β-estradiol (e2) disrupts testis differentiation and causes feminization. following water ... | 2020 | 32645606 |
| altered glutaminase 1 activity during neurulation and its potential implications in neural tube defects. | the neurulation process is regulated by a large amount of genetic and environmental factors that determine the establishment, folding, and fusion of the neural plate to form the neural tube, which develops into the main structure of the central nervous system. a recently described factor involved in this process is glutamate. through nmda ionotropic receptor, glutamate modifies intracellular ca2+ dynamics allowing the oriented cell migration and proliferation, essentials processes in neurulation ... | 2020 | 32636743 |
| the histone h3-h4 tetramer is a copper reductase enzyme. | eukaryotic histone h3-h4 tetramers contain a putative copper (cu2+) binding site at the h3-h3' dimerization interface with unknown function. the coincident emergence of eukaryotes with global oxygenation, which challenged cellular copper utilization, raised the possibility that histones may function in cellular copper homeostasis. we report that the recombinant xenopus laevis h3-h4 tetramer is an oxidoreductase enzyme that binds cu2+ and catalyzes its reduction to cu1+ in vitro. loss- and gain-o ... | 2020 | 32631887 |
| heterologous expression of concatenated nicotinic ach receptors: pros and cons of subunit concatenation and recommendations for construct designs. | concatenation of cys-loop receptor subunits is a commonly used technique to ensure experimental control of receptor assembly. however, we recently demonstrated that widely used constructs did not lead to the expression of uniform pools of ternary and more complex receptors. the aim was therefore to identify viable strategies for designing concatenated constructs that would allow strict control of resultant receptor pools. | 2020 | 32627170 |
| relationship between oxygen consumption and neuronal activity in a defined neural circuit. | neuronal computations related to sensory and motor activity along with the maintenance of spike discharge, synaptic transmission, and associated housekeeping are energetically demanding. the most efficient metabolic process to provide large amounts of energy equivalents is oxidative phosphorylation and thus dependent on o2 consumption. therefore, o2 levels in the brain are a critical parameter that influences neuronal function. measurements of o2 consumption have been used to estimate the cost o ... | 2020 | 32615976 |
| comprehensive imaging of sensory-evoked activity of entire neurons within the awake developing brain using ultrafast aod-based random-access two-photon microscopy. | determining how neurons transform synaptic input and encode information in action potential (ap) firing output is required for understanding dendritic integration, neural transforms and encoding. limitations in the speed of imaging 3d volumes of brain encompassing complex dendritic arbors in vivo using conventional galvanometer mirror-based laser-scanning microscopy has hampered fully capturing fluorescent sensors of activity throughout an individual neuron's entire complement of synaptic inputs ... | 2020 | 32612514 |
| cofactor-enabled functional expression of fruit fly, honeybee, and bumblebee nicotinic receptors reveals picomolar neonicotinoid actions. | the difficulty of achieving robust functional expression of insect nicotinic acetylcholine receptors (nachrs) has hampered our understanding of these important molecular targets of globally deployed neonicotinoid insecticides at a time when concerns have grown regarding the toxicity of this chemotype to insect pollinators. we show that thioredoxin-related transmembrane protein 3 (tmx3) is essential to enable robust expression in xenopus laevis oocytes of honeybee (apis mellifera) and bumblebee ( ... | 2020 | 32611810 |
| disabled-2: a positive regulator of the early differentiation of myoblasts. | dab2 is an adaptor protein and a tumor suppressor. our previous study has found that dab2 was expressed in early differentiating skeletal muscles in mouse embryos. in this study, we determined the role of dab2 in the skeletal muscle differentiation using c2c12 myoblasts in vitro and xenopus laevis embryos in vivo. the expression of dab2 was increased in c2c12 myoblasts during the formation of myotubes in vitro. knockdown of dab2 expression in c2c12 myoblasts resulted in a reduction of myotube fo ... | 2020 | 32607799 |
| comparing the effect of triadimefon and its metabolite on male and female xenopus laevis: obstructed growth and gonad morphology. | amphibians are the most endangered class of vertebrates. in this study, xenopus laevis frogs were exposed to 0, 1 and 10 mg/l of triadimefon or triadimenol. after 14 or 28 days of exposure, high levels of triadimefon or triadimenol obstructed the growth of frogs. however, low levels of triadimefon induced the growth of females after the longer period of exposure. we also found that the antioxidant enzyme activity and ldh levels in males were higher than those in females after 28-days exposure. i ... | 2020 | 32603964 |
| the histone chaperone fact induces cas9 multi-turnover behavior and modifies genome manipulation in human cells. | cas9 is a prokaryotic rna-guided dna endonuclease that binds substrates tightly in vitro but turns over rapidly when used to manipulate genomes in eukaryotic cells. little is known about the factors responsible for dislodging cas9 or how they influence genome engineering. unbiased detection through proximity labeling of transient protein interactions in cell-free xenopus laevis egg extract identified the dimeric histone chaperone facilitates chromatin transcription (fact) as an interactor of sub ... | 2020 | 32603710 |
| active forces shape the metaphase spindle through a mechanical instability. | the metaphase spindle is a dynamic structure orchestrating chromosome segregation during cell division. recently, soft matter approaches have shown that the spindle behaves as an active liquid crystal. still, it remains unclear how active force generation contributes to its characteristic spindle-like shape. here we combine theory and experiments to show that molecular motor-driven forces shape the structure through a barreling-type instability. we test our physical model by titrating dynein act ... | 2020 | 32601228 |
| a turripeptide from polystira nobilis venom inhibits human α3β2 and α7 nicotinic acetylcholine receptors. | almost all marine snails within superfamily conoidea produce venoms containing numerous neuroactive peptides. most toxins characterized from members of this superfamily are produced by species belonging to family conidae. these toxins (conotoxins) affect diverse membrane proteins, such as voltage- and ligand-gated ion channels, including nicotinic acetylcholine receptors (nachrs). family turridae has been considerably less studied than their conidae counterpart and, therefore, turrid toxins (tur ... | 2020 | 32592834 |
| organizing the oocyte: rna localization meets phase separation. | rna localization is a key biological strategy for organizing the cytoplasm and generating both cellular and developmental polarity. during rna localization, rnas are targeted asymmetrically to specific subcellular destinations, resulting in spatially and temporally restricted gene expression through local protein synthesis. first discovered in oocytes and embryos, rna localization is now recognized as a significant regulatory strategy for diverse rnas, both coding and non-coding, in a wide range ... | 2020 | 32591084 |
| contribution of monocarboxylate transporter 6 to the pharmacokinetics and pharmacodynamics of bumetanide in mice. | bumetanide, a sulfamyl loop diuretic, is used for the treatment of edema in association with congestive heart failure. being a polar, anionic compound at physiologic ph, bumetanide uptake and efflux into different tissues is largely transporter-mediated. of note, organic anion transporters (slc22a) have been extensively studied in terms of their importance in transporting bumetanide to its primary site of action in the kidney. the contribution of one of the less-studied bumetanide transporters, ... | 2020 | 32587098 |
| functional analysis of the osnpf4.5 nitrate transporter reveals a conserved mycorrhizal pathway of nitrogen acquisition in plants. | low availability of nitrogen (n) is often a major limiting factor to crop yield in most nutrient-poor soils. arbuscular mycorrhizal (am) fungi are beneficial symbionts of most land plants that enhance plant nutrient uptake, particularly of phosphate. a growing number of reports point to the substantially increased n accumulation in many mycorrhizal plants; however, the contribution of am symbiosis to plant n nutrition and the mechanisms underlying the am-mediated n acquisition are still in the e ... | 2020 | 32586957 |
| acute toxicity of fluazinam to aquatic organisms and its bioaccumulation in brachydanio rerio. | fluazinam (fzn) is a dinitroaniline fungicide. to evaluate the environmental risk of fzn in aquatic environments and ascertain the potential danger to typical aquatic organisms in china, the acute toxicity of fzn to representative aquatic organisms, including brachydanio rerio, chlorella vulgaris beij., daphnia magna straus, and xenopus laevis, was measured, and its bioaccumulation properties in brachydanio rerio were further investigated. the results showed that the acute toxicity of fzn to bra ... | 2020 | 32583109 |
| electromechanical coupling of the kv1.1 voltage-gated k+ channel is fine-tuned by the simplest amino acid residue in the s4-s5 linker. | investigating the shaker-related k+ channel kv1.1, the dysfunction of which is responsible for episodic ataxia 1 (ea1), at the functional and molecular level provides valuable understandings on normal channel dynamics, structural correlates underlying voltage-gating, and disease-causing mechanisms. most studies focused on apparently functional amino acid residues composing voltage-gated k+ channels, neglecting the simplest ones. glycine at position 311 of kv1.1 is highly conserved both evolution ... | 2020 | 32577860 |
| polo-like kinase 1 (plk1) is a positive regulator of dna replication in the xenopus in vitro system. | polo-like kinase 1 (plk1) is a cell cycle kinase essential for mitosis progression, but also important for checkpoint recovery and adaptation in response to dna damage and replication stress. however, although plk1 is expressed in s phase, little is known about its function during unperturbed dna replication. using xenopus laevis egg extracts, mimicking early embryonic replication, we demonstrate that plk1 is simultaneously recruited to chromatin with pre-replication proteins where it accumulate ... | 2020 | 32573322 |
| molecular regulation of α3β4 nicotinic acetylcholine receptors by lupeol in cardiovascular system. | cardiovascular disease (cvd) occurs globally and has a high mortality rate. the highest risk factor for developing cvd is high blood pressure. currently, natural products are emerging for the treatment of hypertension to avoid the side effects of drugs. among existing natural products, lupeol is known to be effective against hypertension in animal experiments. however, there exists no study regarding the molecular physiological evidence against the effects of lupeol. consequently, we investigate ... | 2020 | 32570692 |
| three host plant volatiles, hexanal, lauric acid, and tetradecane, are detected by an antenna-biased expressed odorant receptor 27 in the dark black chafer holotrichia parallela. | insects rely on olfaction to locate their host plants by antennae in complex chemical environments. odorant receptor (or) genes are thought to play a crucial role in the process. ors function together with odorant coreceptors to determine the specificity and sensitivity of olfactory reception. the dark black chafer, holotrichia parallela motschulsky (coleoptera: scarabaeidae), is a destructive underground pest. to understand the molecular basis of h. parallela olfactory reception, an olfactory-b ... | 2020 | 32551589 |
| loc496300 is expressed in the endoderm of developing xenopus laevis embryos. | | 2019 | 32550462 |
| using hdr and a template to introduce an in-frame ha tag on the 3' end of the xenopus laevis gata2.l open reading frame. | | 2019 | 32550411 |
| chemical and voltage gating of gap junction channels expressed in xenopus oocytes. | in most tissues, cells in contact with each other directly intercommunicate via cell-to-cell channels aggregated at gap junctions. direct cell-to-cell communication provides a fundamental mechanism for coordinating many cellular functions in mature and developing organs, as it enables free exchange of small cytosolic molecules. gap junction channels are regulated by a chemical gating mechanism sensitive to cytosolic calcium concentration [ca2+]i in the nanomolar range mediated by ca2+-activated ... | 2020 | 32548808 |
| investigating the impact of the phosphorylation status of tyrosine residues within the tacc domain of tacc3 on microtubule behavior during axon growth and guidance. | axon guidance is a critical process in forming the connections between a neuron and its target. the growth cone steers the growing axon toward the appropriate direction by integrating extracellular guidance cues and initiating intracellular signal transduction pathways downstream of these cues. the growth cone generates these responses by remodeling its cytoskeletal components. regulation of microtubule dynamics within the growth cone is important for making guidance decisions. tacc3, as a micro ... | 2020 | 32543081 |
| the transition state and regulation of γ-turc-mediated microtubule nucleation revealed by single molecule microscopy. | determining how microtubules (mts) are nucleated is essential for understanding how the cytoskeleton assembles. while the mt nucleator, γ-tubulin ring complex (γ-turc) has been identified, precisely how γ-turc nucleates a mt remains poorly understood. here, we developed a single molecule assay to directly visualize nucleation of a mt from purified xenopus laevis γ-turc. we reveal a high γ-/αβ-tubulin affinity, which facilitates assembly of a mt from γ-turc. whereas spontaneous nucleation require ... | 2020 | 32538784 |
| functional characterization of the arabidopsis ammonium transporter atamt1;3 with the emphasis on structural determinants of substrate binding and permeation properties. | atamt1;3 is a major contributor to high-affinity ammonium uptake in arabidopsis roots. using a stable electrophysiological recording strategy, we demonstrate in xenopus laevis oocytes that atamt1;3 functions as a typical high-affinity nh4+ uniporter independent of protons and ca2+. the findings that atamt1;3 transports methylammonium (mea+, a chemical analog of nh4+) with extremely low affinity (km in the range of 2.9-6.1 mm) led to investigate the mechanisms underlying substrate binding. homolo ... | 2020 | 32528489 |
| hcn2 channel-induced rescue of brain teratogenesis via local and long-range bioelectric repair. | embryonic exposure to the teratogen nicotine results in brain defects, by disrupting endogenous spatial pre patterns necessary for normal brain size and patterning. extending prior work in xenopus laevis that showed that misexpression of ion channels can rescue morphogenesis, we demonstrate and characterize a novel aspect of developmental bioelectricity: channel-dependent repair signals propagate long-range across the embryo. we show that distal hcn2 channel misexpression and distal transplants ... | 2020 | 32528251 |
| xela ds2 and xela vs2: two novel skin epithelial-like cell lines from adult african clawed frog (xenopus laevis) and their response to an extracellular viral dsrna analogue. | the skin epithelial layer acts as an important immunological barrier against pathogens and is capable of recognizing and responding to pathogen-associated molecular patterns (pamps) in human and mouse models. although presumed, it is unknown whether amphibian skin epithelial cells exhibit the ability to respond to pamps such as viral double-stranded rna (dsrna). to address this, two cell lines from the dorsal skin (xela ds2) and ventral skin (xela vs2) of the african clawed frog (xenopus laevis) ... | 2020 | 32526291 |
| monoterpenes differently regulate acid-sensitive and mechano-gated k2p channels. | potassium k2p ("leak") channels conduct current across the entire physiological voltage range and carry leak or "background" currents that are, in part, time- and voltage-independent. the activity of k2p channels affects numerous physiological processes, such as cardiac function, pain perception, depression, neuroprotection, and cancer development. we have recently established that, when expressed in xenopus laevis oocytes, k2p2.1 (trek-1) channels are activated by several monoterpenes (mts). he ... | 2020 | 32508645 |
| clearance of activity-evoked k+ transients and associated glia cell swelling occur independently of aqp4: a study with an isoform-selective aqp4 inhibitor. | the mammalian brain consists of 80% water, which is continuously shifted between different compartments and cellular structures by mechanisms that are, to a large extent, unresolved. aquaporin 4 (aqp4) is abundantly expressed in glia and ependymal cells of the mammalian brain and has been proposed to act as a gatekeeper for brain water dynamics, predominantly based on studies utilizing aqp4-deficient mice. however, these mice have a range of secondary effects due to the gene deletion. an efficie ... | 2021 | 32506554 |
| the transcription factor hypermethylated in cancer 1 (hic1) regulates neural crest migration via interaction with wnt signaling. | the transcription factor hypermethylated in cancer 1 (hic1) is associated with both tumorigenesis and the complex human developmental disorder miller-dieker syndrome. while many studies have characterized hic1 as a tumor suppressor, hic1 function in development is less understood. loss-of-function mouse alleles show embryonic lethality accompanied with developmental defects, including craniofacial abnormalities that are reminiscent of human miller-dieker syndrome patients. however, the tissue or ... | 2020 | 32502469 |
| dehydration stress alters the mitogen-activated-protein kinase signaling and chaperone stress response in xenopus laevis. | in arid conditions, the african clawed frog xenopus laevis enters a state of estivation dormancy as an adaptive survival strategy. under estivation, x. laevis experience severe dehydration stress as 25-35% of total body water is lost. dehydration in x. laevis can lead to periods of hypoxia due to elevated blood viscosity that impedes tissue perfusion. to understand how x. laevis survives under such stress, we studied the regulation pattern of key mitogen-activated protein kinases (mapk) and thei ... | 2020 | 32497588 |
| altered thyroid hormone levels affect the capacity for temperature-induced developmental plasticity in larvae of rana temporaria and xenopus laevis. | anuran larvae show phenotypic plasticity in age and size at metamorphosis as a response to temperature variation. the capacity for temperature-induced developmental plasticity is determined by the thermal adaptation of a population. multiple factors such as physiological responses to changing environmental conditions, however, might influence this capacity as well. in anuran larvae, thyroid hormone (th) levels control growth and developmental rate and changes in th status are a well-known stress ... | 2020 | 32479394 |
| the perinuclear er scales nuclear size independently of cell size in early embryos. | nuclear size plays pivotal roles in gene expression, embryo development, and disease. a central hypothesis in organisms ranging from yeast to vertebrates is that nuclear size scales to cell size. this implies that nuclei may reach steady-state sizes set by limiting cytoplasmic pools of size-regulating components. by monitoring nuclear dynamics in early sea urchin embryos, we found that nuclei undergo substantial growth in each interphase, reaching a maximal size prior to mitosis that declined st ... | 2020 | 32473090 |
| association of a novel splice site mutation in p/q-type calcium channels with childhood epilepsy and late-onset slowly progressive non-episodic cerebellar ataxia. | episodic ataxia type 2 (ea2) is characterized by paroxysmal attacks of ataxia with typical onset in childhood or early adolescence. the disease is associated with mutations in the voltage-gated calcium channel alpha 1a subunit (cav2.1) that is encoded by the cacna1a gene. however, previously unrecognized atypical symptoms and the genetic overlap existing between ea2, spinocerebellar ataxia type 6, familial hemiplegic migraine type 1, and other neurological diseases blur the genotype/phenotype co ... | 2020 | 32471306 |
| cloning and expression of cockroach α7 nicotinic acetylcholine receptor subunit. | understanding insect nicotinic acetylcholine receptor (nachr) subtypes is of major interest because they are the main target of several insecticides. in this study, we have cloned a cockroach pameα7 subunit that encodes a 518 amino acid protein with futures typical of nachr subunit, and sequence homology to α7 subunit. pameα7 is differently expressed in the cockroach nervous system, in particular in the antennal lobes, optical lobes and the mushroom bodies where specific expression was found in ... | 2020 | 32457646 |
| experimental platform using the amphibian xenopus laevis for research in fundamental and medical immunology. | the amphibian xenopus constitutes a powerful, versatile, and cost-effective nonmammalian model with which to investigate important contemporary issues of immunity relevant to human health such as ontogeny of immunity, self-tolerance, wound healing, autoimmunity, cancer immunity, immunotoxicology, and adaptation of host immune defenses to emerging pathogens. this model system presents several attractive features: an external developmental environment free of maternal influence that allows for eas ... | 2020 | 32457040 |
| nuclei determine the spatial origin of mitotic waves. | traveling waves play an essential role in coordinating mitosis over large distances, but what determines the spatial origin of mitotic waves remains unclear. here, we show that such waves initiate at pacemakers, regions that oscillate faster than their surroundings. in cell-free extracts of xenopus laevis eggs, we find that nuclei define such pacemakers by concentrating cell cycle regulators. in computational models of diffusively coupled oscillators that account for nuclear import, nuclear posi ... | 2020 | 32452767 |
| the regulation of akt and foxo transcription factors during dehydration in the african clawed frog (xenopus laevis). | the african clawed frog (xenopus laevis) naturally tolerates severe dehydration using biochemical adaptation, one of which is the elevation of antioxidant defenses during whole-body dehydration. the present study investigated the role and regulation of a pathway known to regulate oxidative stress response, the akt-foxo signaling pathway, in clawed frog skeletal muscle, responding to medium (15%) and high (30%) dehydration. protein levels of total and phosphorylated akt, foxo1, and foxo3 were ass ... | 2020 | 32451989 |
| microvascular anatomy of ovary and oviduct in the adult african clawed toad (xenopus laevis daudin, 1802)-histomorphology and scanning electron microscopy of vascular corrosion casts. | ovaries and oviducts of the adult african clawed toad (xenopus laevis daudin, 1802) were studied by light microscopy (lm) of paraplast embedded tissue sections and scanning electron microscopy (sem) of vascular corrosion casts (vccs). histomorphology revealed that ovarian vessels located in the thecal layers. ovarian and interlobar arteries displayed a horse-shoe shaped longitudinally running bundle of vascular smooth muscle cells. follicular blood vessels showed flattened profiles, which were c ... | 2020 | 32449214 |
| optical control of muscular nicotinic channels with azocuroniums, photoswitchable azobenzenes bearing two n-methyl-n-carbocyclic quaternary ammonium groups. | by linking two n-methyl-n-carbocyclic quaternary ammonium groups to an azobenzene scaffold in meta- or para-positions we generated a series of photoswitchable neuromuscular ligands for which we coined the term "azocuroniums". these compounds switched between the (e)- and (z)-isomers by light irradiation at 400-450 nm and 335-340 nm, respectively. meta-azocuroniums were potent nicotinic ligands with a clear selectivity for the muscular nachrs compared to neuronal α7 and α4β2 subtypes, showed good ... | 2020 | 32447198 |
| cross-taxa distinctions in mechanisms of developmental effects for aquatic species exposed to trifluralin. | standard ecological risk assessment practices often rely on larval and juvenile fish toxicity data as representative of the amphibian aquatic phase. empirical evidence suggests that endpoints measured in fish early life stage tests are often sufficient to protect larval amphibians. however, the process of amphibian metamorphosis relies on endocrine cues that affect development and morphological restructuring and are not represented by these test endpoints. the present study compares developmenta ... | 2020 | 32445211 |
| identification of transient receptor potential channel 4-associated protein as a novel candidate gene causing congenital primary hypothyroidism. | congenital primary hypothyroidism (ch) is the most common endocrine disorder in neonates. | 2020 | 32428920 |
| de novo mutations in fbrsl1 cause a novel recognizable malformation and intellectual disability syndrome. | we report truncating de novo variants in specific exons of fbrsl1 in three unrelated children with an overlapping syndromic phenotype with respiratory insufficiency, postnatal growth restriction, microcephaly, global developmental delay and other malformations. the function of fbrsl1 is largely unknown. interestingly, mutations in the fbrsl1 paralogue auts2 lead to an intellectual disability syndrome (auts2 syndrome). we determined human fbrsl1 transcripts and describe protein-coding forms by we ... | 2020 | 32424618 |
| imaging nascent transcription in wholemount vertebrate embryos to characterize zygotic genome activation. | a major event in early embryo development is the awakening of the embryonic genome, a process of large-scale transcriptional induction termed zygotic genome activation (zga). to understand how zga is controlled temporally and spatially, tools are required to image and quantify nascent transcription in wholemount embryos. in this chapter, we describe a metabolic labeling approach that leverages 5-ethynyl uridine (5-eu) incorporation into newly transcribed rnas. subsequently, click chemistry is us ... | 2020 | 32416911 |
| supportive role of the na+ transporter cmhkt1;1 from cucumis melo in transgenic arabidopsis salt tolerance through improved k+/na+ balance. | cmhkt1;1 selectively exports na+ from plant cells. upon nacl stress, its expression increased in a salt-tolerant melon cultivar. overexpression of cmhkt1;1 increased transgenic arabidopsis salt tolerance through improved k+/na+ balance. high-affinity k+ transporters (hkts) are thought to be involved in reducing na+ in plant shoots under salt stress and modulating salt tolerance, but their function in a moderately salt-tolerant species of melon (cucumis melo l.) remains unclear. in this study, a ... | 2020 | 32405802 |
| animal maintenance systems: xenopus laevis. | modular recirculating animal aquaculture systems incorporate uv sterilization and biological, mechanical, and activated carbon filtration, creating a nearly self-contained stable housing environment for xenopus laevis nonetheless, minimal water exchange is necessary to mitigate accumulation of metabolic waste, and regular weekly, monthly, and yearly maintenance is needed to ensure accurate and efficient operation. this protocol describes the methods for establishing a new recirculating system an ... | 2020 | 32404311 |
| altered functional properties of a missense variant in the tresk k+ channel (kcnk18) associated with migraine and intellectual disability. | mutations in the kcnk18 gene that encodes the tresk k2p potassium channel have previously been linked with typical familial migraine with aura. recently, an atypical clinical case has been reported in which a male individual carrying the p.trp101arg (w101r) missense mutation in the kcnk18 gene was diagnosed with intellectual disability and migraine with brainstem aura. here we report the functional characterization of this new missense variant. this mutation is located in a highly conserved resi ... | 2020 | 32394190 |
| managing the oocyte meiotic arrest-lessons from frogs and jellyfish. | during oocyte development, meiosis arrests in prophase of the first division for a remarkably prolonged period firstly during oocyte growth, and then when awaiting the appropriate hormonal signals for egg release. this prophase arrest is finally unlocked when locally produced maturation initiation hormones (mihs) trigger entry into m-phase. here, we assess the current knowledge of the successive cellular and molecular mechanisms responsible for keeping meiotic progression on hold. we focus on tw ... | 2020 | 32392797 |
| differences in intrinsic tubulin dynamic properties contribute to spindle length control in xenopus species. | the function of cellular organelles relates not only to their molecular composition but also to their size. however, how the size of dynamic mesoscale structures is established and maintained remains poorly understood [1-3]. mitotic spindle length, for example, varies several-fold among cell types and among different organisms [4]. although most studies on spindle size control focus on changes in proteins that regulate microtubule dynamics [5-8], the contribution of the spindle's main building b ... | 2020 | 32386526 |
| structure of the cytoplasmic ring of the xenopus laevis nuclear pore complex by cryo-electron microscopy single particle analysis. | the nuclear pore complex (npc) exhibits structural plasticity and has only been characterized at local resolutions of up to 15 å for the cytoplasmic ring (cr). here we present a single-particle cryo-electron microscopy (cryo-em) structure of the cr from xenopus laevis npc at average resolutions of 5.5-7.9 å, with local resolutions reaching 4.5 å. improved resolutions allow identification and placement of secondary structural elements in the majority of the cr components. the two y complexes in e ... | 2020 | 32376910 |
| rpe cells engulf microvesicles secreted by degenerating rod photoreceptors. | rhodopsin is mislocalized to the inner segment plasma membrane (is pm) in various blinding disorders including autosomal-dominant retinitis pigmentosa caused by class i rhodopsin mutations. in these disorders, rhodopsin-laden microvesicles are secreted into the extracellular milieu by afflicted photoreceptor cells. using a xenopus laevis model expressing class i mutant rhodopsin or na+/k+-atpase (nka) fused to dendra2, we fluorescently labeled the microvesicles and found retinal pigment epitheli ... | 2020 | 32376599 |
| renal microvasculature in the adult pipid frog, xenopus laevis: a scanning electron microscope study of vascular corrosion casts. | we studied the opisthonephric (mesonephric) kidneys of adult male and female xenopus laevis using scanning electron microscopy (sem) of vascular corrosion casts and light microscopy of paraplast embedded tissue sections. both techniques displayed glomeruli from ventral to mid-dorsal regions of the kidneys with single glomeruli located dorsally close beneath the renal capsule. glomeruli in general were fed by a single afferent arteriole and drained via a single thinner efferent arteriole into per ... | 2020 | 32374496 |
| molecular characterization of frog vocal neurons using constellation pharmacology. | identification and characterization of neuronal cell classes in motor circuits are essential for understanding the neural basis of behavior. it is a challenging task, especially in a non-genetic-model organism, to identify cell-specific expression of functional macromolecules. here, we performed constellation pharmacology, calcium imaging of dissociated neurons to pharmacologically identify functional receptors expressed by vocal neurons in adult male and female african clawed frogs, xenopus lae ... | 2020 | 32374212 |
| the gria3 c.2477g > a variant causes an exaggerated startle reflex, chorea, and multifocal myoclonus. | hemizygous mutations in gria3 encoding the glua3 subunit of the amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor are known to be associated with neurodevelopmental disorders, including intellectual disability, hypotonia, an autism spectrum disorder, sleep disturbances, and epilepsy in males. | 2020 | 32369665 |
| molecular architecture of the luminal ring of the xenopus laevis nuclear pore complex. | the nuclear pore complex (npc) mediates the flow of substances between the nucleus and cytoplasm in eukaryotic cells. here we report the cryo-electron tomography (cryo-et) structure of the luminal ring (lr) of the npc from xenopus laevis oocyte. the observed key structural features of the lr are independently confirmed by single-particle cryo-electron microscopy (cryo-em) analysis. the lr comprises eight butterfly-shaped subunits, each containing two symmetric wings. each wing consists of four e ... | 2020 | 32367042 |
| stentian structural plasticity in the developing visual system. | in a small fraction of xenopus tadpoles, a single retinal ganglion cell (rgc) axon misprojects to the ipsilateral optic tectum. presenting flashes of light to the ipsilateral eye causes that ipsilateral axon to fire, whereas stimulating the contralateral eye excites all other rgc inputs to the tectum. we performed time-lapse imaging of individual ipsilaterally projecting axons while stimulating either the ipsilateral or contralateral eye. stimulating either eye alone reduced axon elaboration by ... | 2020 | 32366647 |
| combining endocannabinoids with retigabine for enhanced m-channel effect and improved kv7 subtype selectivity. | retigabine is unique among anticonvulsant drugs by targeting the neuronal m-channel, which is composed of kv7.2/kv7.3 and contributes to the negative neuronal resting membrane potential. unfortunately, retigabine causes adverse effects, which limits its clinical use. adverse effects may be reduced by developing m-channel activators with improved kv7 subtype selectivity. the aim of this study was to evaluate the prospect of endocannabinoids as m-channel activators, either in isolation or combined ... | 2020 | 32365171 |
| functional characterization of multifunctional ligands targeting acetylcholinesterase and alpha 7 nicotinic acetylcholine receptor. | alzheimer's disease (ad) is a neurodegenerative disorder associated with cholinergic dysfunction, provoking memory loss and cognitive dysfunction in elderly patients. the cholinergic hypothesis provided over the years with molecular targets for developing palliative treatments for ad, acting on the cholinergic system, namely, acetylcholinesterase and α7 nicotinic acetylcholine receptor (α7 nachr). in our synthetic work, we used "click-chemistry" to synthesize two multi target directed ligands (m ... | 2020 | 32360492 |
| inhibition of cardiac kv4.3 (ito) channel isoforms by class i antiarrhythmic drugs lidocaine and mexiletine. | transient outward k+ current, ito, contributes to cardiac action potential generation and is primarily carried by kv4.3 (kcnd3) channels. two kv4.3 isoforms are expressed in human ventricle and show differential remodeling in heart failure (hf). lidocaine and mexiletine may be applied in selected patients to suppress ventricular arrhythmias, without effects on sudden cardiac death or mortality. isoform-dependent effects of antiarrhythmic drugs on kv4.3 channels and potential implications for rem ... | 2020 | 32360350 |
| effects of ferrocenyl 4-(imino)-1,4-dihydro-quinolines on xenopus laevis prophase i - arrested oocytes: survival and hormonal-induced m-phase entry. | xenopus oocytes were used as cellular and molecular sentinels to assess the effects of a new class of organometallic compounds called ferrocenyl dihydroquinolines that have been developed as potential anti-cancer agents. one ferrocenyl dihydroquinoline compound exerted deleterious effects on oocyte survival after 48 h of incubation at 100 μm. two ferrocenyl dihydroquinoline compounds had an inhibitory effect on the resumption of progesterone induced oocyte meiosis, compared to controls without f ... | 2020 | 32357477 |
| structure of a single-chain h2a/h2b dimer. | chromatin is the complex assembly of nucleic acids and proteins that makes up the physiological form of the eukaryotic genome. the nucleosome is the fundamental repeating unit of chromatin, and is composed of ∼147 bp of dna wrapped around a histone octamer formed by two copies of each core histone: h2a, h2b, h3 and h4. prior to nucleosome assembly, and during histone eviction, histones are typically assembled into soluble h2a/h2b dimers and h3/h4 dimers and tetramers. a multitude of factors inte ... | 2020 | 32356520 |
| how to grow xenopus laevis tadpole stages to adult. | in xenopus laevis, the tadpole stage is characterized by three forms-those occurring before the initiation of limb development, those covering limb development, and those encompassing metamorphosis. maximal tadpole growth, especially during the second form, is critically dependent on good husbandry practices. here we describe a protocol for raising xenopus laevis tadpoles through to adulthood. each step may need to be modified depending on the aquaria used and local conditions. | 2020 | 32350123 |
| effect of nano-encapsulation of β-carotene on xenopus laevis embryos development (fetax). | vitamin a plays a vital role during embryo development as most precursor of embryonic retinoic acid, a key morphogen during embryogenesis. carotenoids, including β-carotene, are important vegetal source of vitamin a and in contrast to teratogenic potential of animal-derived retinoids, β-carotene is usually considered freed from embryotoxic effects and supplements in pregnancy with β-carotene are suggested. the aim of the present work is to evaluate the effect of bulk and nano-encapsulated β-caro ... | 2020 | 32346517 |
| concentration-dependent physiological and transcriptional adaptations of wheat seedlings to ammonium. | conventional wheat production utilizes fertilizers of various nitrogen forms. sole ammonium nutrition has been shown to improve grain quality, despite the potential toxic effects of ammonium at elevated concentrations. we therefore investigated the responses of young seedlings of winter wheat to different nitrogen sources (nh4 no3 = nn, nh4 cl = nnh4+ and kno3 = nno3- ). growth with ammonium-nitrate was superior. however, an elevated concentration of sole ammonium caused severe toxicity symptoms ... | 2020 | 32335941 |
| transcriptional changes caused by estrogenic endocrine disrupting chemicals in gonad-mesonephros complexes of genetic male xenopus laevis: multiple biomarkers for early detection of testis differentiation disruption. | our recent study revealed some early molecular and cellular events in which 17β-estradiol (e2) disrupted testis differentiation and resulted in feminization in xenopus laevis (the african clawed frog), an ideal species for studying reproductive endocrine disruption by estrogenic endocrine disrupting chemicals (edcs). on this basis, we aimed to develop multiple biomarkers for early detection of testis differentiation disruption by estrogenic edcs in x. laevis. tadpoles at stage 45/46 were exposed ... | 2020 | 32335401 |
| the abcf gene family facilitates disaggregation during animal development. | protein aggregation, once believed to be a harbinger and/or consequence of stress, age, and pathological conditions, is emerging as a novel concept in cellular regulation. normal versus pathological aggregation may be distinguished by the capacity of cells to regulate the formation, modification, and dissolution of aggregates. we find that caenorhabditis elegans aggregates are observed in large cells/blastomeres (oocytes, embryos) and in smaller, further differentiated cells (primordial germ cel ... | 2020 | 32320318 |
| spadin selectively antagonizes arachidonic acid activation of trek-1 channels. | trek-1 channel activity is a critical regulator of neuronal, cardiac, and smooth muscle physiology and pathology. the antidepressant peptide, spadin, has been proposed to be a trek-1-specific blocker. here we sought to examine the mechanism of action underlying spadin inhibition of trek-1 channels. heterologous expression in xenopus laevis oocytes and electrophysiological analysis using two-electrode voltage clamp in standard bath solutions was used to characterize the pharmacological profile of ... | 2020 | 32317978 |
| effect of salinity acclimation on osmoregulation, oxidative stress, and metabolic enzymes in the invasive xenopus laevis. | aquatic animals often display physiological adjustments to improve their biological performance and hydrosaline balance in saline environments. in addition to energetic costs associated with osmoregulation, oxidative stress, and the activation of the antioxidant system are common cellular responses to salt stress in many species, but the knowledge of osmoregulation-linked oxidative homeostasis in amphibians is scarce. here we studied the biochemical responses and oxidative responses of xenopus l ... | 2020 | 32306529 |
| preparation of soluble malectin and its tetramer. | malectin is a membrane-anchored endoplasmic reticulum (er)-resident lectin, which is first identified in xenopus laevis in 2008 and highly conserved among animals. malectin plays an important role in the quality control of glycoprotein in the er through recognizing the glc2man9glcnac2 (g2m9) oligosaccharide chain on the newly synthesized glycoproteins. in this chapter, we will describe the preparation of recombinant soluble malectin and its tetramer, which might be developed as useful tools for ... | 2020 | 32306336 |
| neurotoxin merging: a strategy deployed by the venom of the spider cupiennius salei to potentiate toxicity on insects. | the venom of cupiennius salei is composed of dozens of neurotoxins, with most of them supposed to act on ion channels. some insecticidal monomeric neurotoxins contain an α-helical part besides their inhibitor cystine knot (ick) motif (type 1). other neurotoxins have, besides the ick motif, an α-helical part of an open loop, resulting in a heterodimeric structure (type 2). due to their low toxicity, it is difficult to understand the existence of type 2 peptides. here, we show with the voltage cla ... | 2020 | 32290562 |
| multidirectional changes in parameters related to sulfur metabolism in frog tissues exposed to heavy metal-related stress. | the investigations showed changes of the cystathionine γ-lyase (cth), 3-mercaptopyruvate sulfurtransferase (mpst) and rhodanese (tst) activity and gene expression in the brain, heart, liver, kidney, skeletal muscles and testes in frogs pelophylaxridibundus, xenopuslaevis and xenopus tropicalis in response to pb2+, hg2+ and cd2+ stress. the results were analyzed jointly with changes in the expression of selected antioxidant enzymes (cytoplasmic and mitochondrial superoxide dismutase, glutathione ... | 2020 | 32283689 |
| a generalizable optogenetic strategy to regulate receptor tyrosine kinases during vertebrate embryonic development. | ligand-independent activation of receptor tyrosine kinases (rtks) allows for dissecting out the receptor-specific signaling outcomes from the pleiotropic effects of the ligands. in this regard, rtk intracellular domains (icd) are of interest due to their ability to recapitulate signaling activity in a ligand-independent manner when fused to chemical or optical dimerizing domains. a common strategy for synthetic activation of rtks involves membrane tethering of dimerizer-rtk icd fusions. dependin ... | 2020 | 32277988 |
| simple embryo injection of long single-stranded donor templates with the crispr/cas9 system leads to homology-directed repair in xenopus tropicalis and xenopus laevis. | we report model experiments in which simple microinjection of fertilized eggs has been used to effectively perform homology-directed repair (hdr)-mediated gene editing in the two xenopus species used most frequently for research: x. tropicalis and x. laevis. we have used long single-stranded dnas having phosphorothioate modifications as donor templates for hdr at targeted genomic sites using the clustered regularly interspaced short palindromic repeats/crispr-associated protein 9 (crispr/cas9) s ... | 2020 | 32277804 |
| toward the understanding of biology of oocyte life cycle in xenopus laevis: no oocytes left behind. | for the past more than 25 years, we have been focusing on the developmental and reproductive biology of the female gametes, oocytes, and eggs, of the african clawed frog xenopus laevis. | 2020 | 32273815 |
| nastep, an essential protein for self-incompatibility in nicotiana, performs a dual activity as a proteinase inhibitor and as a voltage-dependent channel blocker. | the s-specific pollen rejection response in nicotiana depends on the interaction between s-rnase and a suite of slf proteins. however, the biochemical pathway requires other essential proteins. one of them is the stigmatic protein nastep, which belongs to the kunitz-type protease inhibitor family. within the pollen tubes, nastep is a positive regulator of ht-b stability, likely inhibiting its degradation and, additionally, interacts with nasipp, a mitochondrial phosphate carrier. to gain a deepe ... | 2020 | 32272353 |
| isolation and characterization of a novel member of the acc ligand-gated chloride channel family, hco-lcg-46, from the parasitic nematode haemonchus contortus. | the acc-1 family of cys-loop receptors are ligand-gated chloride channels sensitive to acetylcholine (ach), and are only present in invertebrates. studies of this family of inhibitory receptors has provided insight into how they bind and respond to ach in a manner vastly different from nicotinic acetylcholine receptors and appear to be present in tissues that are relevant to anthelmintic action. here, we have identified two members of the acc-1 family from the parasitic nematode haemonchus conto ... | 2020 | 32268182 |
| the tumor suppressor tff1 occurs in different forms and interacts with multiple partners in the human gastric mucus barrier: indications for diverse protective functions. | tff1 is a protective peptide of the trefoil factor family (tff), which is co-secreted with the mucin muc5ac, gastrokine 2 (gkn2), and igg fc binding protein (fcgbp) from gastric surface mucous cells. tff1-deficient mice obligatorily develop antropyloric adenoma and about 30% progress to carcinomas, indicating that tff1 is a tumor suppressor. as a hallmark, tff1 contains seven cysteine residues with three disulfide bonds stabilizing the conserved tff domain. here, we systematically investigated t ... | 2020 | 32260357 |
| microrna expression in the heart of xenopus laevis facilitates metabolic adaptation to dehydration. | xenopus laevis survive severe dehydration during the summer months in their natural range. microrna regulate translation of target mrnas and have shown to be differentially expressed in response to dehydration in x. laevis. during dehydration, heart rate is elevated which appears to compensate for the reduced oxygen delivery capability due to increased hematocrit. we hypothesized that micrornas would be differentially expressed in the heart to modulate gene expression levels in response to dehyd ... | 2020 | 32259572 |
| natural size variation among embryos leads to the corresponding scaling in gene expression. | xenopus laevis frogs from laboratory stocks normally lay eggs exhibiting extensive size variability. we find that these initial size differences subsequently affect the size of the embryos prior to the onset of growth, and the size of tadpoles during the growth period. even though these tadpoles differ in size, their tissues, organs, and structures always seem to be properly proportioned, i.e. they display static allometry. initial axial patterning events in xenopus occur in a spherical embryo, ... | 2020 | 32259520 |
| pact/prkra and p53 regulate transcriptional activity of dmrt1. | the transcription factor dmrt1 (doublesex and mab-3 related transcription factor) has two distinct functions, somatic-cell masculinization and germ-cell development in some vertebrate species, including mouse and the african clawed frog xenopus laevis. however, its transcriptional regulation remains unclear. we tried to identify dmrt1-interacting proteins from x. laevis testes by immunoprecipitation with an anti-dmrt1 antibody and ms/ms analysis, and selected three proteins, including pact/prkra ... | 2020 | 32251494 |
| αm-conotoxin miiij blocks nicotinic acetylcholine receptors at neuromuscular junctions of frog and fish. | we report the discovery and functional characterization of αm-conotoxin miiij, a peptide from the venom of the fish-hunting cone snail conus magus. injections of αm-miiij induced paralysis in goldfish (carassius auratus) but not mice. intracellular recording from skeletal muscles of fish (c. auratus) and frog (xenopus laevis) revealed that αm-miiij inhibited postsynaptic nicotinic acetylcholine receptors (nachrs) with an ic50 of ~0.1 μm. with comparable potency, αm-miiij reversibly blocked ach-g ... | 2020 | 32245200 |
| trefoil factor family (tff) modules are characteristic constituents of separate mucin complexes in the xenopus laevis integumentary mucus: in vitro binding studies with fim-a.1. | the skin of the frog xenopus laeevis is protected from microbial infections by a mucus barrier that contains frog integumentary mucins (fim)-a.1, fim-b.1, and fim-c.1. these gel-forming mucins are synthesized in mucous glands consisting of ordinary mucous cells and one or more cone cells at the gland base. fim-a.1 and fim-c.1 are unique because their cysteine-rich domains belong to the trefoil factor family (tff). furthermore, fim-a.1 is unusually short (about 400 amino acid residues). in contra ... | 2020 | 32244312 |
| 4-hydroxynonenal induces cx46 hemichannel inhibition through its carbonylation. | hemichannels formed by connexins mediate the exchange of ions and signaling molecules between the cytoplasm and the extracellular milieu. under physiological conditions hemichannels have a low open probability, but in certain pathologies their open probability increases, which can result in cell damage. pathological conditions are characterized by the production of a number of proinflammatory molecules, including 4-hydroxynonenal (4-hne), one of the most common lipid peroxides produced in respon ... | 2020 | 32244060 |
| water-soluble variant of human lynx1 positively modulates synaptic plasticity and ameliorates cognitive impairment associated with α7-nachr dysfunction. | lynx1 is a gpi-tethered protein colocalized with nicotinic acetylcholine receptors (nachrs) in the brain areas important for learning and memory. previously, we demonstrated that at low micromolar concentrations the water-soluble lynx1 variant lacking gpi-anchor (ws-lynx1) acts on α7-nachrs as a positive allosteric modulator. we hypothesized that ws-lynx1 could be used for improvement of cognitive processes dependent on nachrs. here we showed that 2 µm ws-lynx1 increased the acetylcholine-evoked ... | 2020 | 32222974 |
| effects of syntaxins 2, 3, and 4 on rat and human epithelial sodium channel (enac) in xenopus laevis oocytes. | syntaxins are snare proteins and may play a role in epithelial sodium channel (enac) trafficking. the aim of the present study was to investigate the effects of syntaxin 2 (stx2), syntaxin 3 (stx3), and syntaxin 4 (stx4) on rat (renac) and human enac (henac). co-expression of renac and stx3 or stx4 in xenopus laevis oocytes increased amiloride-sensitive whole-cell currents (δiami) on average by 50% and 135%, respectively, compared to oocytes expressing renac alone. in contrast, stx2 had no signi ... | 2020 | 32221667 |
| effect assessment of reclaimed water and carbamazepine exposure on the thyroid axis of x. laevis: apical and histological effects. | there is increasing environmental concern about the constant presence of pharmaceuticals and personal care products (ppcps) in surface water, generally attributed to water discharge from wastewater treatment plants (wwtps) that are unable to completely remove these compounds. the slight, but continuous, presence of these contaminants in reclaimed water (rw) poses a risk of chronic and sublethal toxicity, and the thyroid axis can likely be a target of many of these ppcps. in this work, we address ... | 2020 | 32220735 |
| defining the specific pathogen-free state of xenopus using taqman assays. | colonies of valuable inbred and transgenic laboratory-reared xenopus frogs maintained for research constitute naïve populations of animals susceptible to some opportunistic infectious diseases. therefore, it is prudent to characterize any new animal acquisitions before introduction into an existing colony as a biosecurity measure to preclude the concurrent introduction of an infectious microorganism associated with the new animal(s). in addition, some pathogens of xenopus, such as chlamydia and ... | 2020 | 32213545 |
| action potentials in xenopus oocytes triggered by blue light. | voltage-gated sodium (na+) channels are responsible for the fast upstroke of the action potential of excitable cells. the different α subunits of na+ channels respond to brief membrane depolarizations above a threshold level by undergoing conformational changes that result in the opening of the pore and a subsequent inward flux of na+. physiologically, these initial membrane depolarizations are caused by other ion channels that are activated by a variety of stimuli such as mechanical stretch, te ... | 2020 | 32211871 |
| the actin-family protein arp4 is a novel suppressor for the formation and functions of nuclear f-actin. | the crosstalk between actin and actin-related proteins (arps), namely arp2 and arp3, plays a central role in facilitating actin polymerization in the cytoplasm and also in the nucleus. nuclear f-actin is required for transcriptional regulation, double-strand break repair, and nuclear organization. the formation of nuclear f-actin is highly dynamic, suggesting the involvement of positive and negative regulators for nuclear actin polymerization. while actin assembly factors for nuclear f-actin hav ... | 2020 | 32204557 |
| mechanical stress regulates epithelial tissue integrity and stiffness through the fgfr/erk2 signaling pathway during embryogenesis. | physical forces generated by tissue-tissue interactions are a critical component of embryogenesis, aiding the formation of organs in a coordinated manner. in this study, using xenopus laevis embryos and phosphoproteome analyses, we uncover the rapid activation of the mitogen-activated protein (map) kinase erk2 upon stimulation with centrifugal, compression, or stretching force. we demonstrate that erk2 induces the remodeling of cytoskeletal proteins, including f-actin, an embryonic cadherin c-ca ... | 2020 | 32187556 |