Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
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| differential patterns of inhibition of the sugar transporters glut2, glut5 and glut7 by flavonoids. | only limited data are available on the inhibition of the sugar transporter glut5 by flavonoids or other classes of bioactives. intestinal glut7 is poorly characterised and no information exists concerning its inhibition. we aimed to study the expression of glut7 in caco-2/tc7 intestinal cells, and evaluate inhibition of glucose transport by glut2 and glut7, and of fructose transport by glut2, glut5 and glut7, by flavonoids. differentiated caco-2/tc7 cell monolayers were used to investigate glut7 ... | 2018 | 29548810 |
| comparison of etomidate, benzocaine, and ms222 anesthesia with and without subsequent flunixin meglumine analgesia in african clawed frogs (xenopus laevis). | often few alternative anesthetics for exotic species are available, due to the small numbers of these animals used in research. in this study, we evaluated the depth and duration of anesthesia in xenopus laevis after their immersion in 3 doses of etomidate (15, 22.5, and 30 mg/l) and in 3 doses of benzocaine (0.1%, 0.5%, and 1%) compared with the 'gold standard,' tricaine methanesulfonate (ms222; 2 g/l). we then chose an optimal dose for each alternative anesthetic according to induction time, d ... | 2018 | 29555009 |
| ribosomal rna biogenesis and its response to chilling stress in oryza sativa. | ribosome biogenesis is crucial for plant growth and environmental acclimation. processing of ribosomal rnas (rrnas) is an essential step in ribosome biogenesis and begins with transcription of the rdna. the resulting precursor-rrna (pre-rrna) transcript undergoes systematic processing, where multiple endonucleolytic and exonucleolytic cleavages remove the external and internal transcribed spacers (ets and its). the processing sites and pathways for pre-rrna processing have been deciphered in sac ... | 2018 | 29555785 |
| pharmacological profile of vestibular inhibitory inputs to superior oblique motoneurons. | vestibulo-ocular reflexes (vor) are mediated by three-neuronal brainstem pathways that transform semicircular canal and otolith sensory signals into motor commands for the contraction of spatially specific sets of eye muscles. the vestibular excitation and inhibition of extraocular motoneurons underlying this reflex is reciprocally organized and allows coordinated activation of particular eye muscles and concurrent relaxation of their antagonistic counterparts. here, we demonstrate in isolated p ... | 2018 | 29556714 |
| effects of trimethoprim-sulfadiazine and detomidine on the function of equine kv 11.1 channels in a two-electrode voltage-clamp (tevc) oocyte model. | the long qt syndrome (lqts) is a channelopathy that can lead to severe arrhythmia and sudden cardiac death. pharmacologically induced lqts is caused by interaction between drugs and potassium channels, especially the kv 11.1 channel. due to such interactions, numerous drugs have been withdrawn from the market or are administered with precautions in human medicine. however, some compounds, such as trimethoprim-sulfonamide combinations are still widely used in veterinarian medicine. therefore, we ... | 2018 | 29566261 |
| embryonic lethality is not sufficient to explain hourglass-like conservation of vertebrate embryos. | understanding the general trends in developmental changes during animal evolution, which are often associated with morphological diversification, has long been a central issue in evolutionary developmental biology. recent comparative transcriptomic studies revealed that gene expression profiles of mid-embryonic period tend to be more evolutionarily conserved than those in earlier or later periods. while the hourglass-like divergence of developmental processes has been demonstrated in a variety o ... | 2018 | 29568479 |
| spindle assembly in egg extracts of the marsabit clawed frog, xenopus borealis. | egg extracts of the african clawed frog xenopus laevis have provided a cell-free system instrumental in elucidating events of the cell cycle, including mechanisms of spindle assembly. comparison with extracts from the diploid western clawed frog, xenopus tropicalis, which is smaller at the organism, cellular and subcellular levels, has enabled the identification of spindle size scaling factors. we set out to characterize the marsabit clawed frog, xenopus borealis, which is intermediate in size b ... | 2018 | 29573195 |
| incorporation of the δ-subunit into the epithelial sodium channel (enac) generates protease-resistant enacs in xenopus laevis. | the epithelial sodium channel (enac) is a critical regulator of vertebrate electrolyte homeostasis. enac is the only constitutively open ion channel in the degenerin/enac protein family, and its expression, membrane abundance, and open probability therefore are tightly controlled. the canonical enac is composed of three subunits (α, β, and γ), but a fourth δ-subunit may replace α and form atypical δβγ-enacs. using xenopus laevis as a model, here we found that mrnas of the α- and δ-subunits are d ... | 2018 | 29576549 |
| the right thalamus may play an important role in anesthesia-awakening regulation in frogs. | previous studies have shown that the mammalian thalamus is a key structure for anesthesia-induced unconsciousness and anesthesia-awakening regulation. however, both the dynamic characteristics and probable lateralization of thalamic functioning during anesthesia-awakening regulation are not fully understood, and little is known of the evolutionary basis of the role of the thalamus in anesthesia-awakening regulation. | 2018 | 29576980 |
| proteomic characterization of the neural ectoderm fated cell clones in the xenopus laevis embryo by high-resolution mass spectrometry. | the molecular program by which embryonic ectoderm is induced to form neural tissue is essential to understanding normal and impaired development of the central nervous system. xenopus has been a powerful vertebrate model in which to elucidate this process. however, abundant vitellogenin (yolk) proteins in cells of the early xenopus embryo interfere with protein detection by high-resolution mass spectrometry (hrms), the technology of choice for identifying these gene products. here, we systematic ... | 2018 | 29578674 |
| delay models for the early embryonic cell cycle oscillator. | time delays are known to play a crucial role in generating biological oscillations. the early embryonic cell cycle in the frog xenopus laevis is one such example. although various mathematical models of this oscillating system exist, it is not clear how to best model the required time delay. here, we study a simple cell cycle model that produces oscillations due to the presence of an ultrasensitive, time-delayed negative feedback loop. we implement the time delay in three qualitatively different ... | 2018 | 29579091 |
| orthogonality of pyrrolysine trna in the xenopus oocyte. | chemical aminoacylation of orthogonal trna allows for the genetic encoding of a wide range of synthetic amino acids without the need to evolve specific aminoacyl-trna synthetases. this method, when paired with protein expression in the xenopus laevis oocyte expression system, can extract atomic scale functional data from a protein structure to advance the study of membrane proteins. the utility of the method depends on the orthogonality of the trna species used to deliver the amino acid. here, w ... | 2018 | 29581437 |
| unexplained cardiac arrest: a tale of conflicting interpretations of kcnq1 genetic test results. | unexplained cardiac arrest (uca) is often the first manifestation of an inherited arrhythmogenic disease. genetic testing in uca is challenging due to the complexities of variant interpretation in the absence of supporting cardiac phenotype. we aimed to investigate if a kcnq1 variant [p.(pro64_pro70del)], previously reported as pathogenic, contributes to the long-qt syndrome phenotype, co-segregates with disease or affects kcnq1 function in vitro. | 2018 | 29582136 |
| mitochondrial ros cause motor deficits induced by synaptic inactivity: implications for synapse pruning. | developmental synapse pruning refines burgeoning connectomes. the basic mechanisms of mitochondrial reactive oxygen species (ros) production suggest they select inactive synapses for pruning: whether they do so is unknown. to begin to unravel whether mitochondrial ros regulate pruning, we made the local consequences of neuromuscular junction (nmj) pruning detectable as motor deficits by using disparate exogenous and endogenous models to induce synaptic inactivity en masse in developing xenopus l ... | 2018 | 29587245 |
| high-throughput screening to identify anesthetic ligands using xenopus laevis tadpoles. | general anesthetics are considered among the most significant advances in modern medicine; however, they are also some of the most dangerous commonly administered drugs. despite this, the discovery of novel anesthetics has been slow, with few clinically used agents regardless of their nearly 200-year history. xenopus laevis frogs have a long history as a model organism and provide a vital bridge between in vitro and preclinical mammalian assays. the provided protocols are efficient and cost-effe ... | 2018 | 29588028 |
| trrap is a central regulator of human multiciliated cell formation. | the multiciliated cell (mcc) is an evolutionarily conserved cell type, which in vertebrates functions to promote directional fluid flow across epithelial tissues. in the conducting airway, mccs are generated by basal stem/progenitor cells and act in concert with secretory cells to perform mucociliary clearance to expel pathogens from the lung. studies in multiple systems, includingxenopus laevisepidermis, murine trachea, and zebrafish kidney, have uncovered a transcriptional network that regulat ... | 2018 | 29588376 |
| functional variants in hcn4 and cacna1h may contribute to genetic generalized epilepsy. | genetic generalized epilepsy (gge) encompasses seizure disorders characterized by spike-and-wave discharges (swd) originating within thalamo-cortical circuits. hyperpolarization-activated (hcn) and t-type ca2+ channels are key modulators of rhythmic activity in these brain regions. here, we screened hcn4 and cacna1h genes for potentially contributory variants and provide their functional analysis. | 2017 | 29588962 |
| the degenerin region of the human bile acid-sensitive ion channel (basic) is involved in channel inhibition by calcium and activation by bile acids. | the bile acid-sensitive ion channel (basic) is a member of the enac/degenerin family of ion channels. it is activated by bile acids and inhibited by extracellular ca2+. the aim of this study was to explore the molecular mechanisms mediating these effects. the modulation of basic function by extracellular ca2+ and tauro-deoxycholic acid (t-dca) was studied in xenopus laevis oocytes heterologously expressing human basic using the two-electrode voltage-clamp and outside-out patch-clamp techniques. ... | 2018 | 29589117 |
| mir-206 is required for changes in cell adhesion that drive muscle cell morphogenesis in xenopus laevis. | micrornas (mirnas) are highly conserved small non-coding rna molecules that post-transcriptionally regulate gene expression in multicellular organisms. within the set of muscle-specific mirnas, mir-206 expression is largely restricted to skeletal muscle and is found exclusively within the bony fish lineage. although many studies have implicated mir-206 in muscle maintenance and disease, its role in skeletal muscle development remains largely unknown. here, we examine the role of mir-206 during x ... | 2018 | 29596841 |
| the effects of 4-hydroxybenzoic acid identified from bamboo (dendrocalamus asper) shoots on kv1.4 channel. | bamboo shoot has been used as a treatment for epilepsy in traditional chinese medicine for generations to treat neuronal disorders such as convulsive, dizziness and headaches. 4-hydroxybenzoic acid (4-hba) is a non-flavonoid phenol found abundantly in dendrocalamus asper shoots (bamboo), fruits (strawberries and apples) and flowers. kv1.4 is a rapidly inactivating shaker-related member of the voltage-gated potassium channels with two inactivation mechanisms; the fast n-type and slow c-type. it p ... | 2018 | 29599640 |
| muscarinic modulation of the xenopus laevis tadpole spinal mechanosensory pathway. | muscarinic acetylcholine receptors (machrs) mediate effects of acetylcholine (ach) in many systems, including those involved in spinal functions like locomotion. in xenopus laevis tadpoles at two days old, a model vertebrate for motor control research, we investigated the role of machrs in the skin mechanosensory pathway. we found that machr activation by carbachol did not affect the sensory rohon-beard neuron properties. however, carbachol could hyperpolarise sensory interneurons and decrease t ... | 2018 | 29601952 |
| effects of environmentally relevant sub-chronic atrazine concentrations on african clawed frog (xenopus laevis) survival, growth and male gonad development. | sub-chronic toxicity of environmentally relevant atrazine concentrations on exposed tadpoles and adult male african clawed frogs (xenopus laevis) was evaluated in a quality controlled laboratory for 90 days. the aim of this study was to determine the effects of atrazine on the survival, growth and gonad development of african clawed frogs. after exposure of tadpoles to atrazine concentrations of 0 (control), 0.01, 200 and 500 μg l-1 in water, mortality rates of 0, 0, 3.3 and 70% respectively wer ... | 2018 | 29602044 |
| cellular composition and organization of the spinal cord central canal during metamorphosis of the frog xenopus laevis. | studying the cellular composition and morphological changes of cells lining the central canal during xenopus laevis metamorphosis could contribute to understand postnatal development and spinal cord regeneration. here we report the analysis of central canal cells at different stages during metamorphosis using immunofluorescence for protein markers expression, transmission and scanning electron microscopy and cell proliferation assays. the central canal was regionalized according to expression of ... | 2018 | 29603210 |
| xenopus laevis macrophage-like cells produce xcl-1, an intelectin family serum lectin that recognizes bacteria. | xenopus laevis ca2+ -dependent lectin-1 (xcl-1) is an intelectin family serum lectin that selectively recognizes carbohydrate chains on the bacterial cell surface. immunofluorescence examination of control spleen tissues from normal x. laevis revealed cells producing xcl-1 (xcl-1+ cells) exclusively in red pulps. intraperitoneal injection of escherichia coli lipopolysaccharide (lps) caused a marked increase in the number of xcl-1+ cells in red pulps on day 3, followed by a rapid decrease to near ... | 2018 | 29604105 |
| preparations and protocols for whole cell patch clamp recording of xenopus laevis tectal neurons. | the xenopus tadpole retinotectal circuit, comprised of the retinal ganglion cells (rgcs) in the eye which form synapses directly onto neurons in the optic tectum, is a popular model to study how neural circuits self-assemble. the ability to carry out whole cell patch clamp recordings from tectal neurons and to record rgc-evoked responses, either in vivo or using a whole brain preparation, has generated a large body of high-resolution data about the mechanisms underlying normal, and abnormal, cir ... | 2018 | 29608176 |
| divergent evolutionary trajectories of two young, homomorphic, and closely related sex chromosome systems. | there exists extraordinary variation among species in the degree and nature of sex chromosome divergence. however, much of our knowledge about sex chromosomes is based on comparisons between deeply diverged species with different ancestral sex chromosomes, making it difficult to establish how fast and why sex chromosomes acquire variable levels of divergence. to address this problem, we studied sex chromosome evolution in two species of african clawed frog (xenopus), both of whom acquired novel ... | 2018 | 29608717 |
| distinct mhc class i-like interacting invariant t cell lineage at the forefront of mycobacterial immunity uncovered in xenopus. | the amphibian xenopus laevis is to date the only species outside of mammals where a mhc class i-like (mhc-like) restricted innate-like (i) t cell subset (ivα6 t cells) reminiscent of cd1d-restricted inkt cells has been identified and functionally characterized. this provides an attractive in vivo model to study the biological analogies and differences between mammalian it cells and the evolutionarily antecedent xenopus it cell defense system. here, we report the identification of a unique it cel ... | 2018 | 29610296 |
| new information on morphology and molecular data of camallanid nematodes parasitising xenopus laevis (anura: pipidae) in south africa. | three species of nematodes from the camallanidae that are known to infect xenopus laevis daudin (anura: pipidae) were collected from several localities across south africa. new data on morphology, partial 28s and cox1 genes, infection levels and distribution are presented herein. the most common species, batrachocamallanus slomei southwell et kirshner, 1937, from the stomach and less often oesophagus, was found in eight localities. camallanus kaapstaadi southwell et kirshner, 1937, also from the ... | 2018 | 29611533 |
| aluminum-activated malate transporters can facilitate gaba transport. | plant aluminum-activated malate transporters (almts) are currently classified as anion channels; they are also known to be regulated by diverse signals, leading to a range of physiological responses. gamma-aminobutyric acid (gaba) regulation of anion flux through almt proteins requires a specific amino acid motif in almts that shares similarity with a gaba binding site in mammalian gabaa receptors. here, we explore why taalmt1 activation leads to a negative correlation between malate efflux and ... | 2018 | 29618628 |
| an intersubunit electrostatic interaction in the gabaa receptor facilitates its responses to benzodiazepines. | benzodiazepines are positive allosteric modulators of the gabaa receptor (gabaar), acting at the α-γ subunit interface to enhance gabaar function. gaba or benzodiazepine binding induces distinct conformational changes in the gabaar. the molecular rearrangements in the gabaar following benzodiazepine binding remain to be fully elucidated. using two molecular models of the gabaar, we identified electrostatic interactions between specific amino acids at the α-γ subunit interface that were broken by ... | 2018 | 29622679 |
| micrornp-mediated translational activation of nonadenylated mrnas in a mammalian cell-free system. | micrornas are small noncoding rnas that regulate translation and mrna stability by binding target mrnas in complex with argonaute (ago) proteins. ago interacts with a member of the tnrc6 family proteins to form a micrornp complex, which recruits the ccr4-not complex to accelerate deadenylation and inhibits translation. micrornas primarily repress translation of target mrnas but have been shown to enhance translation of a specific type of target reporter mrnas in various experimental systems: g0 ... | 2018 | 29626383 |
| an ex vivo assay for screening glucocorticoid signaling disruption based on glucocorticoid-response gene transcription in xenopus tails. | there is a pressing need for developing in vivo or ex vivo assays to screen the glucocorticoid (gc) signaling disruption of chemicals. thus, we aimed to establish an ex vivo assay for screening gc signaling disruption based on the gc-response gene transcription in xenopus laevis tails cultured ex vivo. firstly, we investigated effects of corticosterone (cort, a main gc in frogs) on gc-response gene expression, and determined the six genes as molecular endpoints for assaying the gc signaling disr ... | 2018 | 29628076 |
| tbx2 is required for the suppression of mesendoderm during early xenopus development. | t-box family proteins are dna-binding transcriptional regulators that play crucial roles during germ layer formation in the early vertebrate embryo. well-characterized members of this family, including the transcriptional activators brachyury and vegt, are essential for the proper formation of mesoderm and endoderm, respectively. to date, t-box proteins have not been shown to play a role in the promotion of the third primary germ layer, ectoderm. | 2018 | 29633424 |
| expression of the inactivating deiodinase, deiodinase 3, in the pre-metamorphic tadpole retina. | thyroid hormone (th) orchestrates amphibian metamorphosis. thus, this developmental phase is often used to study th-dependent responses in specific tissues. however, th signaling appears early in development raising the question of the control of th availability in specific cell types prior to metamorphosis. th availability is under strict temporal and tissue-specific control by deiodinases. we examined the expression of the th-inactivating enzyme, deiodinase type 3 (d3), during early retinal de ... | 2018 | 29641587 |
| transgenic xenopus laevis line for in vivo labeling of nephrons within the kidney. | xenopus laevis embryos are an established model for studying kidney development. the nephron structure and genetic pathways that regulate nephrogenesis are conserved between xenopus and humans, allowing for the study of human disease-causing genes. xenopus embryos are also amenable to large-scale screening, but studies of kidney disease-related genes have been impeded because assessment of kidney development has largely been limited to examining fixed embryos. to overcome this problem, we have g ... | 2018 | 29642376 |
| new targets for old drugs: cardiac glycosides inhibit atrial-specific k2p3.1 (task-1) channels. | cardiac glycosides have been used in the treatment of arrhythmias for more than 200 years. two-pore-domain (k2p) potassium channels regulate cardiac action potential repolarization. recently, k2p3.1 [tandem of p domains in a weak inward rectifying k+ channel (twik)-related acid-sensitive k+ channel (task)-1] has been implicated in atrial fibrillation pathophysiology and was suggested as an atrial-selective antiarrhythmic drug target. we hypothesized that blockade of cardiac k2p channels contribu ... | 2018 | 29643254 |
| developmental expression profiles and thyroidal regulation of cytokines during metamorphosis in the amphibian xenopus laevis. | early life-stages of amphibians rely on the innate immune system for defense against pathogens. while thyroid hormones (th) are critical for metamorphosis and later development of the adaptive immune system, the role of th in innate immune system development is less clear. an integral part of the innate immune response are pro-inflammatory cytokines - effector molecules that allow communication between components of the immune system. the objective of this study was to characterize the expressio ... | 2018 | 29656046 |
| atopt6 protein functions in long-distance transport of glutathione in arabidopsis thaliana. | the involvement of the arabidopsis oligopeptide transporter atopt6, which was previously shown to take up glutathione (gsh) when expressed in yeast cells or in xenopus laevis oocytes, in gsh transport was analyzed using opt6 knockout mutant lines. the concentration of gsh in flowers or siliques was lower in opt6 mutants relative to wild-type plants, suggesting involvement of atopt6 in long-distance transport of gsh. the gsh concentration in phloem sap was similar between opt6 mutants and wild-ty ... | 2018 | 29669129 |
| galantamine is not a positive allosteric modulator of human α4β2 or α7 nicotinic acetylcholine receptors. | the alkaloid galantamine was originally isolated from the green snowdrop galanthus woronowii and is currently marketed as a drug for treatment of mild to moderate dementia in patients with alzheimer's disease. in addition to a well-documented proficiency to inhibit acetylcholinesterase, galantamine has been reported to increase neuronal nicotinic ach (nach) receptor function by acting as a positive allosteric modulator. yet there remains controversy regarding these findings in the literature. to ... | 2018 | 29669164 |
| fluorescent anesthetics. | methods for using exogenous fluorophore and general anesthetic 1-aminoanthracene (1-ama) and its photoactive derivative 1-azidoanthracene (1-aza) are provided. 1-ama potentiates gabaa chloride currents and immobilizes xenopus laevis tadpoles. cellular and tissue anesthetic distribution can be imaged for quantifying "on-pathway" and "off-pathway" targets. 1-aza shares targets with 1-ama and offers further optoanesthetic spatial and temporal control upon near-uv laser irradiation. furthermore, 1-a ... | 2018 | 29673536 |
| effects of multiple life stage exposure to the fungicide prochloraz in xenopus laevis: manifestations of antiandrogenic and other modes of toxicity. | the larval amphibian growth and development assay (lagda) is an internationally harmonized testing guideline for evaluating effects of chronic chemical exposure in amphibians. in order to evaluate the effects of chronic exposure to an antiandrogenic chemical in an amphibian model, prochloraz was tested using a variation of the lagda design. exposure was initiated with <1d post-fertilization embryos at nominal concentrations of 0, 6.7, 20, 60 and 180 μg/l (0, 18, 53, 159, 478 nm) and continued in ... | 2018 | 29674245 |
| comparison of oocyte mrna localization patterns in sterlet acipenser ruthenus and african clawed frog xenopus laevis. | in oocytes, rna localization has critical implications, as assembly of proteins in particular subcellular domains is crucial to embryo development. the distribution of mrna molecules can identify and characterize localized transcripts. the goal of this study was to clarify the origin of primordial germ cells in the oocyte body plan and to reveal the generation of cell lineages by localized rnas. the distribution of 12 selected mrnas in sterlet acipenser ruthenus oocytes was investigated by qpcr ... | 2018 | 29682883 |
| new apetx-like peptides from sea anemone heteractis crispa modulate asic1a channels. | sea anemones are an abundant source of various biologically active peptides. the hydrophobic 20% ethanol fraction of tropical sea anemone heteractis crispa was shown to contain at least 159 peptide compounds including neurotoxins, proteinase and α-amylase inhibitors, as well as modulators of acid-sensing ion channels (asics). the three new peptides, π-anmtx hcr 1b-2, -3, and -4 (41 aa) (short names hcr 1b-2, -3, -4), identified by a combination of reversed-phase liquid chromatography and mass sp ... | 2018 | 29684594 |
| developmental toxicity of dibutyl phthalate and citrate ester plasticizers in xenopus laevis embryos. | citrate esters have been considered as alternatives to phthalate plasticizers. being considered to have low toxicity in mammals, their toxicological information for aquatic animals remains poorly understood. we examined the developmental toxicity of citrate esters including tributyl o-acetylcitrate (atbc), triethyl 2-acetylcitrate (atec), and trihexyl o-acetylcitrate (athc) together with dibutyl phthalate (dbp) based on the frog embryo teratogenesis assay-xenopus (fetax). atbc has the lowest 96 ... | 2018 | 29684872 |
| microvascular anatomy of the brain of the adult pipid frog, xenopus laevis (daudin): a scanning electron microscopic study of vascular corrosion casts. | to demonstrate the 3d microvascular anatomy of the brain of the model organism xenopus laevis daudin scanning electron microscopy of vascular corrosion casts was correlated with light microscopy of stained 7 µm thick serial tissues sections. results showed that supplying arteries descended from the leptomeningeal surface without remarkable branchings straight to the subventricular zone where they branched and capillarized. capillaries showed few h- and/or y-shaped anastomoses during their centri ... | 2018 | 29693258 |
| effect of hemin, baicalein and heme oxygenase-1 (ho-1) enzyme activity inhibitors on cd-induced accumulation of ho-1, hsps and aggresome-like structures in xenopus kidney epithelial cells. | cadmium is a highly toxic environmental pollutant that can cause many adverse effects including cancer, neurological disease and kidney damage. aquatic amphibians are particularly susceptible to this toxicant as it was shown to cause developmental abnormalities and genotoxic effects. in mammalian cells, the accumulation of heme oxygenase-1 (ho-1), which catalyzes the breakdown of heme into co, free iron and biliverdin, was reported to protect cells against potentially lethal concentrations of cd ... | 2018 | 29698685 |
| roles of xenopus chemokine ligand cxclh (xcxclh) in early embryogenesis. | several chemokine molecules control cell movements during early morphogenesis. however, it is unclear whether chemokine molecules affect cell fate. here, we identified and characterized the cxc-type chemokine ligand in xenopus laevis, xenopus cxclh (xcxclh), during early embryogenesis. xcxclh is expressed in the dorsal vegetal region at the gastrula stage. both overexpression and knockdown of xcxclh in the dorsal region inhibited gastrulation. xcxclh contributed to the attraction of mesendoderma ... | 2018 | 29700804 |
| xenopus laevis oocyte as a model for the study of the cytoskeleton. | at the beginning of diplotene, the oocyte of xenopus laevis is a cell of about 10-20 microns destined to increase 10,000-fold its size when the oocyte becomes filled with yolk platelets and has accumulated a great number of pigment granules in a half of its periphery. its internal architecture is gradually accomplished during growth because of several factors, especially because of cytoskeletal changes. in the fully-grown oocyte, the cytoskeleton appears to sustain the eccentrically located germ ... | 2018 | 29705198 |
| nmda receptor signaling is important for neural tube formation and for preventing antiepileptic drug-induced neural tube defects. | failure of neural tube closure leads to neural tube defects (ntds), which can have serious neurological consequences or be lethal. use of antiepileptic drugs (aeds) during pregnancy increases the incidence of ntds in offspring by unknown mechanisms. here we show that during xenopus laevis neural tube formation, neural plate cells exhibit spontaneous calcium dynamics that are partially mediated by glutamate signaling. we demonstrate that nmda receptors are important for the formation of the neura ... | 2018 | 29712790 |
| is adult cardiac regeneration absent in xenopus laevis yet present in xenopus tropicalis? | we recently used an endoscopy-based resection method to explore the consequences of cardiac injury in adult xenopus laevis, obtaining the result that the adult xenopus heart is unable to regenerate. at 11 months post-amputation, cellular and biological marks of scarring persisted. we thus concluded that, contrary to urodeles and teleosts, adult anurans share a cardiac injury outcome similar to adult mammals. however, in their work published in this journal on the 13 december 2017, liao et al. sh ... | 2018 | 29713454 |
| cardiac regeneration in xenopus tropicalis and xenopus laevis: discrepancies and problems. | two studies have recently focused on adult heart regeneration in xenopus. while we reported on cardiac myogenic regeneration in xenopus tropicalis after injury, marshall and colleagues found no regeneration in an injured heart in xenopus laevis. here, we would like to join the discussion initiated by marshall et al. who debated the methods and species differences in both studies. we agree with their view that the species difference in cardiac regenerative capacity could lead to different results ... | 2018 | 29713455 |
| transposable elements and polyploid evolution in animals. | polyploidy in animals is much less common than in plants, where it is thought to be pervasive in all higher plant lineages. recent studies have highlighted the impact of polyploidization and the associated process of diploidy restoration on the evolution and speciation of selected taxonomic groups in the animal kingdom: from vertebrates represented by salmonid fishes and african clawed frogs to invertebrates represented by parasitic root-knot nematodes and bdelloid rotifers. in this review, we f ... | 2018 | 29715568 |
| deciphering the molecular determinants of cholinergic anthelmintic sensitivity in nematodes: when novel functional validation approaches highlight major differences between the model caenorhabditis elegans and parasitic species. | cholinergic agonists such as levamisole and pyrantel are widely used as anthelmintics to treat parasitic nematode infestations. these drugs elicit spastic paralysis by activating acetylcholine receptors (achrs) expressed in nematode body wall muscles. in the model nematode caenorhabditis elegans, genetic screens led to the identification of five genes encoding levamisole-sensitive-achr (l-achr) subunits: unc-38, unc-63, unc-29, lev-1 and lev-8. these subunits form a functional l-achr when hetero ... | 2018 | 29719008 |
| a role for sox9 in post-transcriptional processes: insights from the amphibian oocyte. | sox9 is a member of the gene family of sox transcription factors, which is highly conserved among vertebrates. it is involved in different developmental processes including gonadogenesis. in all amniote species examined thus far, sox9 is expressed in the sertoli cells of the male gonad, suggesting an evolutionarily conserved role in testis development. however, in the anamniotes, fishes and amphibians, it is also expressed in the oocyte but the significance of such an expression remains to be el ... | 2018 | 29740094 |
| foxo4 activity is regulated by phosphorylation and the cellular environment during dehydration in the african clawed frog, xenopus laevis. | the african clawed frog, xenopus laevis, is capable of enduring seasonal bouts of severe dehydration stress resulting from transcriptional regulation that facilitates a pro-survival response. previous studies have shown that dehydration increases antioxidant gene expression in this amphibian. as foxo4 is known to regulate several antioxidant genes, we sought to understand how differential phosphorylation and environmental factors (urea, temperature) may contribute to its transcriptional regulati ... | 2018 | 29746959 |
| yokukansan contains compounds that antagonize the 5-ht3 receptor. | we recently focused on alkaloids in uncaria hook (a constituent of the kampo medicine, yokukansan) and identified the pharmacological action of geissoschizine methyl ether on several g protein-coupled receptors. however, the functions of other identified alkaloids in uncaria hook, including hirsutine, hirsuteine, rhynchophylline, isorhynchophylline, corynoxeine, isocorynoxeine, are not clear. | 2018 | 29747744 |
| determination of metals and pharmaceutical compounds released in hospital wastewater from toluca, mexico, and evaluation of their toxic impact. | due to the activities inherent to medical care units, the hospital effluent released contains diverse contaminants such as tensoactives, disinfectants, metals, pharmaceutical products and chemical reagents, which are potentially toxic to the environment since they receive no treatment or are not effectively removed by such treatment before entering the drain. they are incorporated into municipal wastewater, eventually entering water bodies where they can have harmful effects on organisms and can ... | 2018 | 29751329 |
| retraction of rod-like mitochondria during microtubule-dependent transport. | molecular motors play relevant roles on the regulation of mitochondria size and shape, essential properties for the cell homeostasis. in this work, we tracked single rod-shaped mitochondria with nanometer precision to explore the performance of microtubule motor teams during processive anterograde and retrograde transport. we analyzed simultaneously the organelle size and verified that mitochondria retracted during retrograde transport with their leading tip moving slower in comparison with the ... | 2018 | 29752335 |
| ligand binding and activation properties of the purified bacterial cyclic nucleotide-gated channel sthk. | cyclic nucleotide-modulated ion channels play several essential physiological roles. they are involved in signal transduction in photoreceptors and olfactory sensory neurons as well as pacemaking activity in the heart and brain. investigations of the molecular mechanism of their actions, including structural and electrophysiological characterization, are restricted by the availability of stable, purified protein obtained from accessible systems. here, we establish that sthk, a cyclic nucleotide- ... | 2018 | 29752414 |
| identification of loop d domain amino acids in the human aquaporin-1 channel involved in activation of the ionic conductance and inhibition by aqb011. | aquaporins are integral proteins that facilitate the transmembrane transport of water and small solutes. in addition to enabling water flux, mammalian aquaporin-1 (aqp1) channels activated by cyclic gmp can carry non-selective monovalent cation currents, selectively blocked by arylsulfonamide compounds aqb007 (ic50 170 μm) and aqb011 (ic50 14 μm). in silico models suggested that ligand docking might involve the cytoplasmic loop d (between aqp1 transmembrane domains 4 and 5), but the predicted si ... | 2018 | 29755973 |
| expression variation and covariation impair analog and enable binary signaling control. | due to noise in the synthesis and degradation of proteins, the concentrations of individual vertebrate signaling proteins were estimated to vary with a coefficient of variation (cv) of approximately 25% between cells. such high variation is beneficial for population-level regulation of cell functions but abolishes accurate single-cell signal transmission. here, we measure cell-to-cell variability of relative protein abundance using quantitative proteomics of individual xenopus laevis eggs and cu ... | 2018 | 29759982 |
| rxr ligands modulate thyroid hormone signaling competence in young xenopus laevis tadpoles. | appropriate thyroid hormone (th) signaling through thyroid hormone receptors (trs) is essential for vertebrate development. amphibian metamorphosis is initiated and sustained through the action of th on trs, which are conserved across vertebrates. trs heterodimerize with retinoid x receptors (rxrs) on thyroid hormone response elements (tres) in the genome; however, in most cell line and adult animal studies, rxr ligands do not affect expression of tr target genes. we used a quantitative, precoci ... | 2018 | 29762675 |
| coulomb and ch-π interactions in (6-4) photolyase-dna complex dominate dna binding and repair abilities. | (6-4) photolyases ((6-4)pls) are flavoenzymes that repair the carcinogenic uv-induced dna damage, pyrimidine(6-4)pyrimidone photoproducts ((6-4)pps), in a light-dependent manner. although the reaction mechanism of dna photorepair by (6-4)pls has been intensively investigated, the molecular mechanism of the lesion recognition remains obscure. we show that a well-conserved arginine residue in xenopus laevis (6-4)pl (xl64) participates in dna binding, through coulomb and ch-π interactions. fragment ... | 2018 | 29762762 |
| retinoic acid-induced expression of hnf1b and fzd4 is required for pancreas development in xenopus laevis. | retinoic acid (ra) is required for pancreas specification in xenopus and other vertebrates. however, the gene network that is directly induced by ra signalling in this context remains to be defined. by rna sequencing of in vitro-generated pancreatic explants, we identified the genes encoding the transcription factor hnf1β and the wnt-receptor fzd4/fzd4s as direct ra target genes. functional analyses of hnf1b and fzd4/fzd4s in programmed pancreatic explants and whole embryos revealed their requir ... | 2018 | 29769220 |
| cell transplantation as a method to investigate spinal cord regeneration in regenerative and nonregenerative xenopus stages. | mammals are not capable of regenerating their central nervous system (cns); anamniotes, however, can regenerate in response to injury. the mechanisms that explain the different regenerative capabilities include: (i) extrinsic mechanisms that consider the cellular environment and extracellular matrix composition, (ii) intrinsic factors implicating the presence or absence of genetic programs that promote axon regeneration, and (iii) the presence or absence of neural stem and progenitors cells (nsp ... | 2018 | 29769390 |
| infrared laser-mediated gene induction at the single-cell level in the regenerating tail of xenopus laevis tadpoles. | we describe a precise and reproducible gene-induction method in the amphibian, xenopus laevis tetrapod amphibians are excellent models for studying the mechanisms of three-dimensional organ regeneration because they have an exceptionally high regenerative ability. however, spatial and temporal manipulation of gene expression has been difficult in amphibians, hindering studies on the molecular mechanisms of organ regeneration. recently, however, development of a xenopus transgenic system with a h ... | 2018 | 29769391 |
| methods for investigating the larval period and metamorphosis in xenopus. | anuran metamorphosis resembles postembryonic development in mammals, a period around birth when many organs/tissues mature into their adult form as circulating thyroid and stress hormone levels are high. unlike uterus-enclosed mammalian embryos, tadpoles develop externally and undergo the dramatic changes of hormone-dependent development totally independent of maternal influence, making them a valuable model in which to study vertebrate postembryonic organ development and maturation. various pro ... | 2018 | 29769395 |
| larval thymectomy of xenopus laevis. | in jawed vertebrates from sharks to mammals, the thymus is the primary (or central) lymphoid tissue where t cells develop and mature. the particular stromal cell types, cytokine environment, and tissue organization in the thymus are essential for v(d)j recombination, positive selection for major histocompatibility complex recognition, and negative selection against self-peptide recognition of most αβ t cells. the thymectomy operation on xenopus tadpole larva described here creates a t-cell-defic ... | 2018 | 29769397 |
| dissecting and culturing animal cap explants. | the animal cap explant is a simple but adaptable tool available to developmental biologists. the use of animal cap explants in demonstrating the presence of mesoderm-inducting activity in the xenopus embryo vegetal pole is one of many elegant examples of their worth. animal caps respond to a range of growth factors (e.g., wnts, fgf, tgf-β), making them especially useful for studying signal transduction pathways and gene regulatory networks. explants are also suitable for examining cell behavior ... | 2018 | 29769399 |
| septin-dependent remodeling of cortical microtubule drives cell reshaping during epithelial wound healing. | wounds in embryos heal rapidly through contraction of the wound edges. despite well-recognized significance of the actomyosin purse string for wound closure, roles for other cytoskeletal components are largely unknown. here, we report that the septin cytoskeleton cooperates with actomyosin and microtubules to coordinate circumferential contraction of the wound margin and concentric elongation of wound-proximal cells in xenopus laevis embryos. microtubules reoriented radially, forming bundles alo ... | 2018 | 29777035 |
| rod-specific ablation using the nitroreductase/metronidazole system to investigate regeneration in xenopus. | genetically controlled cell type-specific ablation provides a reproducible method to induce regeneration that can be temporally and spatially controlled. until recently, regeneration studies in xenopus have relied on surgical methods to stimulate regeneration. these methods are labor intensive and not as reproducible as a genetically controlled approach. in this protocol we describe selective ablation of rod photoreceptors in the premetamorphic xenopus laevis retina using the nitroreductase/metr ... | 2018 | 29789402 |
| a novel clcn5 pathogenic mutation supports dent disease with normal endosomal acidification. | dent disease is an x-linked recessive renal tubular disorder characterized by low-molecular-weight proteinuria, hypercalciuria, nephrolithiasis, nephrocalcinosis, and progressive renal failure. inactivating mutations of clcn5, the gene encoding the 2cl- /h+ exchanger clc-5, have been reported in patients with dent disease 1. in vivo studies in mice harboring an artificial mutation in the "gating glutamate" of clc-5 (c.632a > c, p.glu211ala) and mathematical modeling suggest that endosomal chlori ... | 2018 | 29791050 |
| conserved rna binding activity of a yin-yang 1 homologue in the ova of the purple sea urchin strongylocentrotus purpuratus. | yin-yang 1 (yy1) is a highly conserved transcription factor possessing rna-binding activity. a putative yy1 homologue was previously identified in the developmental model organism strongylocentrotus purpuratus (the purple sea urchin) by genomic sequencing. we identified a high degree of sequence similarity with yy1 homologues of vertebrate origin which shared 100% protein sequence identity over the dna- and rna-binding zinc-finger region with high similarity in the n-terminal transcriptional act ... | 2018 | 29795182 |
| living xenopus oocytes, eggs, and embryos as models for cell division. | xenopus laevis has long been a popular model for studies of development and, based on the use of cell-free extracts derived from its eggs, as a model for reconstitution of cell cycle regulation and other basic cellular processes. however, work over the last several years has shown that intact xenopus eggs and embryos are also powerful models for visualization and characterization of cell cycle-regulated cytoskeletal dynamics. these findings were something of a surprise, given that the relatively ... | 2018 | 29804672 |
| asymmetric distribution of biomolecules of maternal origin in the xenopus laevis egg and their impact on the developmental plan. | asymmetric cell division is a ubiquitous feature during the development of higher organisms. asymmetry is achieved by differential localization or activities of biological molecules such as proteins, and coding and non-coding rnas. here, we present subcellular transcriptomic and proteomic analyses along the animal-vegetal axis of xenopus laevis eggs. more than 98% of the maternal mrnas could be categorized into four localization profile groups: animal, vegetal, extremely vegetal, and a newly des ... | 2018 | 29844480 |
| the calcium-sensing receptor increases activity of the renal ncc through the wnk4-spak pathway. | background hypercalciuria can result from activation of the basolateral calcium-sensing receptor (casr), which in the thick ascending limb of henle's loop controls ca2+ excretion and nacl reabsorption in response to extracellular ca2+ however, the function of casr in the regulation of nacl reabsorption in the distal convoluted tubule (dct) is unknown. we hypothesized that casr in this location is involved in activating the thiazide-sensitive nacl cotransporter (ncc) to prevent nacl loss.methods ... | 2018 | 29848507 |
| in vivo mitotic spindle scaling can be modulated by changing the levels of a single protein: the microtubule polymerase xmap215. | in many organisms, early embryonic development is characterized by a series of reductive cell divisions that result in rapid increases in cell number and concomitant decreases in cell size. intracellular organelles, such as the nucleus and mitotic spindle, also become progressively smaller during this developmental window, but the molecular and mechanistic underpinnings of these scaling relationships are not fully understood. for the mitotic spindle, changes in cytoplasmic volume are sufficient ... | 2018 | 29851557 |
| n-terminal and central domains of apc function to regulate branch number, length and angle in developing optic axonal arbors in vivo. | during formation of neuronal circuits, axons navigate long distances to reach their target locations in the brain. when axons arrive at their target tissues, in many cases, they extend collateral branches and/or terminal arbors that serve to increase the number of synaptic connections they make with target neurons. here, we investigated how adenomatous polyposis coli (apc) regulates terminal arborization of optic axons in living xenopus laevis tadpoles. the n-terminal and central domains of apc ... | 2018 | 29856981 |
| progress toward identifying causes of maldevelopment induced in xenopus by pond water and sediment extracts from minnesota, usa. | in previously conducted laboratory studies with the south african clawed frog (xenopus laevis), pond water and sediment samples collected from various sites in minnesota, usa, were demonstrated to have the potential to induce a variety of developmental abnormalities, including early embryo-larval maldevelopment, abnormal limb development, and disruption of metamorphosis. the results of exposure of x. laevis to suspect pond water and sediment samples supported the hypothesis that these samples we ... | 1999 | 29857636 |
| comparative toxicity of ammonium and nitrate compounds to pacific treefrog and african clawed frog tadpoles. | the effects of ammonium nitrate, ammonium chloride, ammonium sulfate, and sodium nitrate on survival and growth of pacific treefrog (pseudacris regilla [baird and girard]) and african clawed frog (xenopus laevis [daudin]) tadpoles were determined in static-renewal tests. the 10-d ammonium nitrate and ammonium sulfate lc50s for p. regilla were 55.2 and 89.7 mg/l nh4 -n, respectively. the 10-d lc50s for x. laevis for the three ammonium compounds ranged from 45 to 64 μg/l nh4 - n. the 10-d sodium n ... | 1999 | 29857645 |
| akt signaling displays multifaceted functions in neural crest development. | akt signaling is an essential intracellular pathway controlling cell homeostasis, cell proliferation and survival, as well as cell migration and differentiation in adults. alterations impacting the akt pathway are involved in many pathological conditions in human disease. similarly, during development, multiple transmembrane molecules, such as fgf receptors, pdgf receptors or integrins, activate akt to control embryonic cell proliferation, migration, differentiation, and also cell fate decisions ... | 2018 | 29859890 |
| testicular and androgen dependence of skin gland morphology in the anurans, xenopus laevis and rana pipiens. | in anuran amphibians, there is increasing evidence that exocrine glands dispersed throughout the general integument are secondary sex characters (ssc). following the recent discovery of sexually dimorphic "breeding glands" in the dorsum of male rana pipiens, we studied the effects of castration and testosterone treatment on the dorsal skin glands of male xenopus laevis and r. pipiens to determine whether the dorsal breeding glands, or any other dorsal skin glands, are androgen dependent. the dor ... | 1993 | 29865448 |
| ultrastructural changes in the connective tissue of the gastric region during the metamorphosis of xenopus laevis. | development of the gastric connective tissue of xenopus laevis during metamorphosis was investigated by electron microscopy. throughout the larval period to stage 60, the layer of connective tissue underlying the gastric epithelium consists of immature fibroblasts surrounded by a sparse extracellular matrix. at the beginning of the transition from the larval to the adult epithelial form, at about stage 60, extensive changes occur in the connective tissue. the number of cells suddenly increses an ... | 1989 | 29865622 |
| development of the ethmoidal structures of the endocranium in the anuran pipa pipa. | investigation of eight developmental stages by means of serial sections and subsequent graphic or wax model reconstructions, as well as by means of cleared-and-stained and dissected material, revealed that the ethmoidal endocranium in pipa pipa consists in early states of a single horizontal ethmoid plate lacking labial cartilages. later in the course of development, structures comparable with those in other anurans appear, though modified and of reduced size. these adult structures arise from t ... | 1989 | 29865644 |
| spiral waves and vertebrate embryonic handedness. | during early embryonic development, the vertebrate main body axis is segmented from head-to-tail into somites. somites emerge sequentially from the presomitic mesoderm (psm) as a consequence of oscillatory waves of genetic activity, called somitogenesis waves. here, we discuss the implications of the dynamic patterns of early x-delta-2 expression in the prospective somites (somitomeres) of xenopus laevis. we report that right somitomeres normally emerge before left to form chiral structures (i.e ... | 2018 | 29872025 |
| molecular insights into variable electron transfer in amphibian cryptochrome. | cryptochrome proteins are activated by the absorption of blue light, leading to the formation of radical pairs through electron transfer in the active site. recent experimental studies have shown that once some of the amino acid residues in the active site of xenopus laevis cryptochrome dash are mutated, radical-pair formation is still observed. in this study, we computationally investigate electron-transfer pathways in the x. laevis cryptochrome dash by extensively equilibrating a previously es ... | 2018 | 29874607 |
| premotor neuron divergence reflects vocal evolution. | to identify mechanisms of behavioral evolution, we investigated the hindbrain circuit that generates distinct vocal patterns in two closely related frog species. male xenopus laevis and xenopus petersii produce courtship calls that include a fast trill: trains of ∼60 hz sound pulses. although fast trill rates are similar, x. laevis fast trills have a longer duration and period than those of x. petersii to pinpoint the neural basis of these differences, we used whole-cell patch-clamp recordings i ... | 2018 | 29875228 |
| mechanism of how augmin directly targets the γ-tubulin ring complex to microtubules. | microtubules (mts) must be generated from precise locations to form the structural frameworks required for cell shape and function. mts are nucleated by the γ-tubulin ring complex (γ-turc), but it remains unclear how γ-turc gets to the right location. augmin has been suggested to be a γ-turc targeting factor and is required for mt nucleation from preexisting mts. to determine augmin's architecture and function, we purified xenopus laevis augmin from insect cells. we demonstrate that augmin is su ... | 2018 | 29875259 |
| genome-wide transcriptomics analysis of genes regulated by gata4, 5 and 6 during cardiomyogenesis in xenopus laevis. | the transcription factors gata4, gata5 and gata6 play important roles in heart muscle differentiation. the data presented in this article are related to the research article entitled "genome-wide transcriptomics analysis identifies sox7 and sox18 as specifically regulated by gata4 in cardiomyogenesis" (afouda et al., 2017) [1]. the present study identifies genes regulated by these individual cardiogenic gata factors using genome-wide transcriptomics analysis. we have presented genes that are spe ... | 2018 | 29876429 |
| lrpap1 as a specific marker of proximal pronephric kidney tubuli in xenopus laevis embryos. | lrpap1, also known as receptor associated protein (rap) is a small protein of 40 kda associated with six of the seven members of the evolutionary conserved family of ldl receptors. numerous studies showed that lrpap1 has a dual function, initially as a chaperone insuring proper formation of intermolecular disulfide bonds during biogenesis of low density lipoprotein (ldl) receptors and later as an escort protein during trafficking through the endoplasmic reticulum and the early golgi compartment, ... | 2018 | 29877571 |
| pou3f transcription factor expression during embryonic development highlights distinct pou3f3 and pou3f4 localization in the xenopus laevis kidney. | the pou (pit-oct-unc) genes encode a large transcription factor family comprising 6 classes (pou1f to pou6f ) involved in many developmental processes, such as cell commitment and differentiation. the pou3f class contains four members (pou3f1, pou3f2, pou3f3, pou3f4) characterized by expression in ectodermal tissue derivatives, such as nervous system and otic vesicle, during mammalian development. in order to obtain insights into the potential conservation of this class of transcription factors ... | 2018 | 29877572 |
| atrial fibrillation and heart failure-associated remodeling of two-pore-domain potassium (k2p) channels in murine disease models: focus on task-1. | understanding molecular mechanisms involved in atrial tissue remodeling and arrhythmogenesis in atrial fibrillation (af) is essential for developing specific therapeutic approaches. two-pore-domain potassium (k2p) channels modulate cellular excitability, and task-1 (k2p3.1) currents were recently shown to alter atrial action potential duration in af and heart failure (hf). finding animal models of af that closely resemble pathophysiological alterations in human is a challenging task. this study ... | 2018 | 29881975 |
| evaluating thyroid disrupting chemicals in vivo using xenopus laevis. | using in vivo animal model systems for chemical screening can permit evaluation of the signaling pathways implicated. xenopus laevis is an ideal model organism to test thyroid axis disruption as thyroid hormones are highly conserved across vertebrates. here, we describe a high-throughput assay using non-feeding embryonic stage transgenic x. laevis (th/bzip) to screen for thyroid disrupting chemicals using a 3 day exposure protocol. we further describe a protocol to detect endocrine disruption of ... | 2018 | 29892825 |
| role of thyroid hormone receptor in amphibian development. | the amphibian xenopus laevis has long been used as a model for studying vertebrate cell and developmental biology largely due to the easiness to manipulate this system in vivo and in vitro. while most of the developmental studies have been on xenopus embryogenesis, considerable efforts have been made to understand its metamorphosis, a process mimicking postembryonic development in mammals when many organs mature into their adult forms in the presence of high levels of thyroid hormone (t3). amphi ... | 2018 | 29892830 |
| ex vivo eye tissue culture methods for xenopus. | lens regeneration can be studied in whole animals following removal of the original lens (lentectomy). however, culturing a whole animal can be impractical for assays involving small molecule inhibitors or proteins. ex vivo eye tissue culture is an alternative approach for examining lens regeneration. the ex vivo culture system offers certain advantages when compared to the in vivo regeneration assay, as the percentage of cases showing lens differentiation can exceed that seen in whole animals. ... | 2019 | 29895561 |
| investigating the cellular and molecular mechanisms of wound healing in xenopus oocytes and embryos. | the african clawed frog xenopus has remarkable capacities to heal wounds rapidly and to regenerate complex tissues. because of its experimental tractability, studies using xenopus oocytes, embryos, and larvae have contributed extensively to our understanding of the molecular and cellular mechanisms underpinning wound healing and tissue regeneration. in this protocol, we describe wound-healing assays following mechanical or laser injuries of oocytes and multicellular epithelia in xenopus laevis e ... | 2019 | 29895564 |
| studies of limb regeneration in larval xenopus. | a basic protocol is given for animal maintenance and surgery in studies of hindlimb regeneration in larval xenopus laevis unlike urodele limbs, those of larval frogs typically show much more variation in the extent of regeneration after amputation. such variation can be reduced by optimizing the conditions of larval maintenance to regulate the rates of growth and development, by selecting only larvae with normal rates of growth and morphological development for experimental use, and by attention ... | 2019 | 29895566 |
| biological concerns on the selection of animal models for teratogenic testing. | during pregnancy fetus can be exposed to a variety of chemicals which may induce abortion and malformations. due to the amounts of new substances coming into the market every year, a high demand for a rapid, reliable, and cost-effective method to detect potential toxicity is necessary. different species have been used as animal models for teratogen screening, most of them sharing similar development processes with humans. however, the application of embryology knowledge to teratology is hampered ... | 2018 | 29896687 |
| evaluation of teratogenicity of pharmaceuticals using fetax. | pharmaceuticals are chemical compounds which are used to preserve human and animal health. once administered, these compounds are metabolized or can remain unaltered until excreted. therefore, a mixture of pharmaceuticals and their metabolites enters municipal sewers and wastewater treatment plants where, depending on their polarity, water solubility, and persistence, they cannot be completely removed or transformed during the treatment process, so that unaltered pharmaceuticals and/or their met ... | 2018 | 29896699 |
| visualization of gene expression patterns by in situ hybridization on early stages of development of xenopus laevis. | in situ hybridization performed using whole fixed embryos provides accurate and detailed visualization of gene expression patterns. these patterns are useful for investigating spatial patterns of gene expression in normally developing embryos but can also be useful in investigating the effects of genetic or environmental changes on expression of genetic markers characteristic of particular tissues, organs, or genetic pathways. our lab's protocol for whole-mount in situ hybridization is presented ... | 2018 | 29896701 |