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modeling ocular lens disease in xenopus.ocular lens clouding is termed as cataract, which depending on the onset, is classified as congenital or age-related. developing new cataract treatments requires new models. thus far, xenopus embryos have not been evaluated as a system for studying cataract.202031872467
bupropion inhibits serotonin type 3ab heteromeric channels at clinically relevant concentrations.bupropion, a food and drug administration-approved antidepressant and smoking cessation aid, blocks dopamine and norepinephrine reuptake transporters and noncompetitively inhibits nicotinic acetylcholine and serotonin (5-ht) type 3a receptors (5-ht3ars). 5-ht3 receptors are pentameric ligand-gated ion channels that regulate synaptic activity in the central and peripheral nervous system, presynaptically and postsynaptically. in the present study, we examined and compared the effect of bupropion a ...202031871303
the γ-hydroxybutyric acid (ghb) analogue ncs-382 is a substrate for both monocarboxylate transporters subtypes 1 and 4.the small-molecule ligand (e)-2-(5-hydroxy-5,7,8,9-tetrahydro-6h-benzo[7]annulen-6-ylidene)acetic acid (ncs-382) is an analogue of γ-hydroxybutyric acid (ghb) and is widely used for probing the brain-specific ghb high-affinity binding sites. to reach these, brain uptake is imperative, and it is therefore important to understand the molecular mechanisms of ncs-382 transport in order to direct in vivo studies. in this study, we hypothesized that ncs-382 is a substrate for the monocarboxylate trans ...202031866563
applying tensile and compressive force to xenopus animal cap tissue.over many years, the xenopus laevis embryo has provided a powerful model system to investigate how mechanical forces regulate cellular function. here, we describe a system to apply reproducible tensile and compressive force to x. laevis animal cap tissue explants and to simultaneously assess cellular behavior using live confocal imaging.202031857437
insights into the assembly and activation of the microtubule nucleator γ-turc.microtubules are dynamic polymers of α- and β-tubulin and have crucial roles in cell signalling, cell migration, intracellular transport and chromosome segregation1. they assemble de novo from αβ-tubulin dimers in an essential process termed microtubule nucleation. complexes that contain the protein γ-tubulin serve as structural templates for the microtubule nucleation reaction2. in vertebrates, microtubules are nucleated by the 2.2-megadalton γ-tubulin ring complex (γ-turc), which comprises γ-t ...202031856152
organ-specific requirements for thyroid hormone receptor ensure temporal coordination of tissue-specific transformations and completion of xenopus metamorphosis.background: thyroid hormone (triiodothyronine [t3]) is essential for the development throughout vertebrates. anuran metamorphosis mimics mammalian postembryonic development, a period around birth when plasma t3 level peaks and many organs/tissues mature into their adult forms. compared with the uterus-enclosed mammalian embryos, tadpoles can be easily manipulated to study the roles of t3 and t3 receptors (trs) in tissue remodeling and adult organ development. we and others have previously knocke ...202031854240
bringing immersive science to undergraduate laboratory courses using crispr gene knockouts in frogs and butterflies.the use of crispr/cas9 for gene editing offers new opportunities for biology students to perform genuine research exploring the gene-to-phenotype relationship. it is important to introduce the next generation of scientists, health practitioners and other members of society to the technical and ethical aspects of gene editing. here, we share our experience leading hands-on undergraduate laboratory classes, where students formulate hypotheses regarding the roles of candidate genes involved in deve ...202032034043
annexin a3 is necessary for parallel artery-vein alignment in the mouse retina.annexin a3 (anxa3) is a member of the calcium-regulated, cell membrane-binding family of annexin proteins. we previously confirmed that anxa3 is expressed in the endothelial lineage in vertebrates and that loss of anxa3 in xenopus laevis leads to embryonic blood vessel defects. however, the biological function of anxa3 in mammals is completely unknown. in order to investigate anxa3 vascular function in mammals, we generated an endothelial cell-specific anxa3 conditional knockout mouse model (anx ...202032020697
active emigration from climate change-caused seawater intrusion into freshwater habitats.ecological risk assessment associated with seawater intrusions has been supported on the determination of lethal/sublethal effects following standard protocols that force exposure neglecting the ability of mobile organisms to spatially avoid salinized environments. thus, this work aimed at assessing active emigration from climate change-caused seawater intrusion into freshwater habitats. to specific objectives were delineated: first, to compute median 12-h avoidance conductivities (ac50,12h) for ...202031883492
heparan sulfate proteoglycans regulate bmp signalling during neural crest induction.bone morphogenetic protein (bmp) signalling is key to many developmental processes, including early regionalisation of the ectoderm. the neural crest is induced here by a combination of bmp and wnt signals from nearby tissues with many secreted factors contributing to its initial specification at the neural plate border. gremlin 1 (grem1) is a secreted bmp antagonist expressed in the neural crest in xenopus laevis but its function here is unknown. as well as binding bmps, grem1 has been shown to ...202031883440
d-glucuronolactone attenuates para-xylene-induced defects in neuronal development and plasticity in xenopus tectum in vivo.xylene and its derivatives are known to be neurotoxic to the central nervous system of animals. our previous work has shown that para-xylene (px) can cause an increase in apoptotic cells and abnormal avoidance behavior in xenopus laevis. however, the mechanism underlying the impact of px on neuronal structural and functional plasticity is less clear. here, we examined the effects of px on neuronal development and plasticity in the developing optic tectum. we found that huc/d-positive neurons wer ...202031811891
analysis of clcnkb mutations at dimer-interface, calcium-binding site, and pore reveals a variety of functional alterations in clc-kb channel leading to bartter syndrome.pathological missense mutations in clcnkb gene give a wide spectrum of clinical phenotypes in bartter syndrome type iii patients. molecular analysis of the mutated clc-kb channels can be helpful to classify the mutations according to their functional alteration. we investigated the functional consequences of nine mutations in the clcnkb gene causing bartter syndrome. we first established that all tested mutations lead to decreased clc-kb currents. combining electrophysiological and biochemical m ...202031803959
role of trka signaling during tadpole tail regeneration and early embryonic development in xenopus laevis.neurotrophic signaling regulates neural cell behaviors in development and physiology, although its role in regeneration has not been fully investigated. here, we examined the role of neurotrophic signaling in xenopus laevis tadpole tail regeneration. after the tadpole tails were amputated, the expression of neurotrophin ligand family genes, especially ngf and bdnf, was up-regulated as regeneration proceeded. moreover, notochordal expression of the ngf receptor gene trka, but not that of other ne ...202031788928
studying in vivo retinal progenitor cell proliferation in xenopus laevis.the efficient generation and maintenance of retinal progenitor cells (rpcs) are key goals needed for developing strategies for productive eye repair. although vertebrate eye development and retinogenesis are well characterized, the mechanisms that can initiate rpc proliferation following injury-induced regrowth and repair remain unknown. this is partly because endogenous rpc proliferation typically occurs during embryogenesis while studies of retinal regeneration have largely utilized adult (or ...202031786778
molecular characterization of the orphan transporter slc16a9, an extracellular ph- and na+-sensitive creatine transporter.human monocarboxylate transporters (hmcts) mediate the transport of monocarboxylates across plasma membranes. one such transporter, hmct9, has been shown to be related to serum uric acid levels and the risk of renal overload gout. however, the functional characteristics of hmct9 remain unknown. the aim of this study was to investigate the expression and localization of hmct9 using a xenopus laevis oocyte heterologous expression system and characterize its transport properties. kinetic analysis o ...202031784090
a glimpse of the peptide profile presentation by xenopus laevis mhc class i: crystal structure of pxela-uaa reveals a distinct peptide-binding groove.the african clawed frog, xenopus laevis, is a model species for amphibians. before metamorphosis, tadpoles do not efficiently express the single classical mhc class i (mhc-i) molecule xela-uaa, but after metamorphosis, adults express this molecule in abundance. to elucidate the ag-presenting mechanism of xela-uaa, in this study, the xela-uaa structure complex (pxela-uaag) bound with a peptide from a synthetic random peptide library was determined. the amino acid homology between the xela-uaa and ...202031776204
endoplasmic reticulum transmembrane protein tmtc3 contributes to o-mannosylation of e-cadherin, cellular adherence, and embryonic gastrulation.protein glycosylation plays essential roles in protein structure, stability, and activity such as cell adhesion. the cadherin superfamily of adhesion molecules carry o-linked mannose glycans at conserved sites and it was recently demonstrated that the transmembrane and tetratricopeptide repeat-containing proteins 1-4 (tmtc1-4) gene products contribute to the addition of these o-linked mannoses. here, biochemical, cell biological, and organismal analysis was used to determine that tmtc3 supports ...202031851597
desensitization of nmda channels requires ligand binding to both glun1 and glun2 subunits to constrict the pore beside the activation gate.n-methyl-d-aspartate (nmda) receptor channels are activated by glutamate (or nmda) and glycine. the channels also undergo desensitization, which denotes decreased channel availability, after prolonged exposure to the activating ligands. glycine apparently has a paradoxical negative effect on desensitization, as the increase in ambient glycine in concentrations required for channel activation would increase sustained nmda receptor currents. we hypothesized that this classical "glycine-dependent d ...202031821563
apple almt9 requires a conserved c-terminal domain for malate transport underlying fruit acidity.malate accumulation in the vacuole largely determines apple (malus domestica) fruit acidity, and low fruit acidity is strongly associated with truncation of ma1, an ortholog of aluminum-activated malate transporter9 (almt9) in arabidopsis (arabidopsis thaliana). a mutation at base 1,455 in the open reading frame of ma1 leads to a premature stop codon that truncates the protein by 84 amino acids at its c-terminal end. here, we report that both the full-length protein, ma1, and its naturally occur ...202031772076
effect of triadimefon and its metabolite on adult amphibians xenopus laevis.the decrease in the population of amphibians all over the world has raised concerns. adult x. laevis frogs were exposed to 0, 1 and 10 mg/l triadimefon and triadimenol. after 14 or 28 days exposure, we collected male and female specimens to study swimming activity, lactic dehydrogenase (ldh) and antioxidant enzyme activity in blood samples, histopathology of liver and thyroid tissue, thyroid hormone levels and thyroid hormone-related gene expression levels in brains. our results showed that tria ...202031743868
ligand binding characteristics of the ku80 von willebrand domain.the n-terminal von willebrand domain of ku80 supports interactions with a ku binding motif (kbm) that has been identified in at least three other dna repair proteins: the non-homologous end joining (nhej) scaffold aplf, the modulator of retrovirus infection, mri, and the werner syndrome protein (wrn). a second, more recently identified ku binding motif present in xlf and several other proteins (kbmx) has also been reported to interact with this domain. the isolated ku80 von willebrand antigen do ...202031733588
tomato roots have a functional silicon influx transporter but not a functional silicon efflux transporter.silicon (si) accumulation in shoots differs greatly with plant species, but the molecular mechanisms for this interspecific difference are unknown. here, we isolated homologous genes of rice si influx (sllsi1) and efflux (sllsi2) transporter genes in tomato (solanum lycopersicum l.) and functionally characterized these genes. sllsi1 showed transport activity for si when expressed in both rice lsi1 mutant and xenopus laevis oocytes. sllsi1 was constitutively expressed in the roots. immunostaining ...202031724184
the flavor enhancer maltol increases pigment aggregation in dermal and neural melanophores in xenopus laevis tadpoles.melanophores are pigmented cells that change the distribution of melanosomes, enabling animals to appear lighter or darker for camouflage, thermoregulation, and protection from ultraviolet radiation. a complex series of hormonal and neural mechanisms regulates melanophore pigment distribution, making these dynamic cells a valuable tool to screen toxicants as they rapidly respond to changes in the environment. we found that maltol, a naturally occurring flavor enhancer and fragrance agent, induce ...202031721268
iron nanoparticle bio-interactions evaluated in xenopus laevis embryos, a model for studying the safety of ingested nanoparticles.iron nanoparticles (nps) have been proposed as a tool in very different fields such as environmental remediation and biomedical applications, including food fortification against iron deficiency, even if there is still concern about their safety. here, we propose xenopus laevis embryos as a suitable model to investigate the toxicity and the bio-interactions at the intestinal barrier of fe3o4 and zerovalent iron (zvi) nps compared to fe(ii) and (iii) salts in the 5 to 100 mg fe/l concentration ra ...202031718350
toward decoding bioelectric events in xenopus embryogenesis: new methodology for tracking interplay between calcium and resting potentials in vivo.although chemical signaling during embryogenesis is readily addressed by a plethora of available techniques, the developmental functions of ionic signaling are still poorly understood. it is increasingly realized that bioelectric events in nonneural cells are critical for pattern regulation, but their study has been hampered by difficulties in monitoring and manipulating them in vivo. recent developments in visualizing electrical signaling dynamics in the field of neuroscience have facilitated f ...202031711960
arabidopsis pic30 encodes a major facilitator superfamily transporter responsible for the uptake of picolinate herbicides.picloram is an auxinic herbicide that is widely used for controlling broad leaf weeds. however, its mechanism of transport into plants is poorly understood. in a genetic screen for picloram resistance, we identified three arabidopsis mutant alleles of pic30 (picloram resistant30) that are specifically resistant to picolinates, but not to other auxins. pic30 is a previously uncharacterized gene that encodes a major facilitator superfamily (mfs) transporter. similar to most members of mfs, pic30 c ...202031710151
serotonin and mucxs release by small secretory cells depend on xpod, a ssc specific marker gene.mucus secretion and ciliary motility are hallmarks for muco-ciliary epithelia (mce). both, mammalian airways as well as the less complex epidermis of xenopus embryos show cilia-driven mucus flow to protect the organism against harmful effects by exogenous pathogens or pollutants. four cell types set up the epidermal mce in xenopus. multi-ciliated cells (mccs) generate an anterior to posterior flow of mucus. ion secreting cells (iscs) are characterized by the expression of ion transporters, presu ...202031705622
the hkt transporter hvhkt1;5 negatively regulates salt tolerance.maintaining low intracellular na+ concentrations is an essential physiological strategy in salt stress tolerance in most cereal crops. here, we characterized a member of the high-affinity k+ transporter (hkt) family in barley (hordeum vulgare), hvhkt1;5, which negatively regulates salt tolerance and has different functions from its homology in other cereal crops. hvhkt1;5 encodes a plasma membrane protein localized to root stele cells, particularly in xylem parenchyma cells adjacent to the xylem ...202031690708
simple method to characterize the ciliary proteome of multiciliated cells.motile cilia of multiciliated epithelial cells have important roles in animal development and cell homeostasis. although several studies have identified and reported proteins localized in this complex organelle and the related immotile primary cilia from various cell types, it is still challenging to isolate high quantities of ciliary proteins for proteomic analysis. in this study, african clawed frog (xenopus laevis) embryos, which have many multiciliated cells in the epidermis, were treated wi ...202031689115
complement c1q subunit molecules from xenopus laevis possess conserved function in c1q-immunoglobulin interaction.complement component 1q (c1q), together with c1r and c1s to form c1, recognize and bind immune complex to initiate the classical complement pathway. in this study, c1q subunit molecules (xlc1qa, xlc1qb, xlc1qc) were cloned and analyzed from xenopus laevis (x. laevis). the open reading frame (orf) of xlc1qa is 819 bp of nucleotide sequence encoding 272 amino acids, the orf of xlc1qb is 711 bp encoding 236 aa, and the xlc1qc is consists of 732 bp encoding 243 aa. the deduced amino acid sequences c ...202031678076
identification and characterization of the atlantic salmon peptide transporter 1a.peptide transporter 1 (pept1) mediates the uptake of dietary di-/tripeptides in vertebrates. however, in teleost fish gut, more than one pept1-type transporter might operate, because of teleost-specific whole gen(om)e duplication event(s) that occurred during evolution. here, we describe a novel teleost di-/tripeptide transporter, i.e., the atlantic salmon (salmo salar) peptide transporter 1a [pept1a; or solute carrier family 15 member 1a (slc15a1a)], which is a paralog (77% similarity and 64% i ...202031664857
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 ...202031593685
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 ...202031591723
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 ...202031350763
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 ...202031552666
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 ...202031551010
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 ...202031509333
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 ...202031425913
pannexin 1 activation and inhibition is permeant-selective.the large-pore channel pannexin 1 (panx1) is expressed in many cell types and can open upon different, yet not fully established, stimuli. panx1 permeability is often inferred from channel permeability to fluorescent dyes, but it is currently unknown whether dye permeability translates to permeability to other molecules. cell shrinkage and c-terminal cleavage led to a panx1 open-state with increased permeability to atomic ions (current), but did not alter ethidium uptake. panx1 inhibitors affect ...202031698505
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. ...202031629886
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 ...202031372684
the expression of key guidance genes at a forebrain axon turning point is maintained by distinct fgfr isoforms but a common downstream signal transduction mechanism.during development the axons of neurons grow toward and locate their synaptic partners to form functional neural circuits. axons do so by reading a map of guidance cues expressed by surrounding tissues. guidance cues are expressed at a precise space and time, but how guidance cue expression is regulated, and in a coordinated manner, is poorly understood. semaphorins (semas) and slits are families of molecular ligands that guide axons. we showed previously that fibroblast growth factor (fgf) sign ...202030993182
effects of glyphosate and a commercial formulation roundup® exposures on maturation of xenopus laevis oocytes.pesticides are often found at high concentrations in small ponds near agricultural field where amphibians are used to live and reproduce. even if there are many studies on the impacts of phytopharmaceutical active ingredients in amphibian toxicology, only a few are interested in the earlier steps of their life cycle. while their populations are highly threatened with extinction. the aim of this work is to characterize the effects of glyphosate and its commercial formulation roundup® gt max on th ...202030835066
adverse effects of fly ashes used as immobilizing agents for highly metal-contaminated soils on xenopus laevis oocytes survival and maturation-a study performed in the north of france with field soil extracts.amphibians are now recognized as the most endangered group. one of this decline causes is the degradation of their habitat through direct contamination of water, soil leaching, or runoff from surrounding contaminated soils and environments. in the north of france, the extensive industrial activities resulted in massive soil contamination by metal compounds. mineral amendments were added to soils to decrease trace metal mobility. because of the large areas to be treated, the use of inexpensive in ...202030875069
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 ...202031601998
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 ...202032502469
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 ...202032497588
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 ...202032479394
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 ...202032473090
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 ...202032471306
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 ...202032457646
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 ...202032457040
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 ...202032452767
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 ...202032451989
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 ...202032449214
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 ...202032447198
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 ...202032445211
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.202032428920
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 ...202032424618
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 ...202032416911
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 ...202032405802
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 ...202032404311
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 ...202032394190
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 ...202032392797
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 ...202032386526
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 ...202032376910
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 ...202032376599
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 ...202032374496
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 ...202032374212
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.202032369665
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 ...202032367042
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 ...202032366647
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 ...202032365171
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 ...202032360492
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 ...202032360350
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 ...202032357477
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 ...202032356520
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.202032350123
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 ...202032346517
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 ...202032335941
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 ...202032335401
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 ...202032320318
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 ...202032317978
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 ...202032306529
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 ...202032306336
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 ...202032290562
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 ...202032283689
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 ...202032277988
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 ...202032277804
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.202032273815
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 ...202032272353
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 ...202032268182
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 ...202032260357
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 ...202032259572
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, ...202032259520
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 ...202032251494
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 ...202032245200
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 ...202032244312
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 ...202032244060
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 ...202032222974
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