Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
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| cell volume changes regulate slick (slo2.1), but not slack (slo2.2) k+ channels. | slick (slo2.1) and slack (slo2.2) channels belong to the family of high-conductance k+ channels and have been found widely distributed in the cns. both channels are activated by na+ and cl- and, in addition, slick channels are regulated by atp. therefore, the roles of these channels in regulation of cell excitability as well as ion transport processes, like regulation of cell volume, have been hypothesized. it is the aim of this work to evaluate the sensitivity of slick and slack channels to sma ... | 2014 | 25347289 |
| sulfonylureas suppress the stimulatory action of mg-nucleotides on kir6.2/sur1 but not kir6.2/sur2a katp channels: a mechanistic study. | sulfonylureas, which stimulate insulin secretion from pancreatic β-cells, are widely used to treat both type 2 diabetes and neonatal diabetes. these drugs mediate their effects by binding to the sulfonylurea receptor subunit (sur) of the atp-sensitive k(+) (katp) channel and inducing channel closure. the mechanism of channel inhibition is unusually complex. first, sulfonylureas act as partial antagonists of channel activity, and second, their effect is modulated by mgadp. we analyzed the molecul ... | 2014 | 25348414 |
| lack of negatively charged residues at the external mouth of kir2.2 channels enable the voltage-dependent block by external mg2+. | kir channels display voltage-dependent block by cytosolic cations such as mg2+ and polyamines that causes inward rectification. in fact, cations can regulate k channel activity from both the extracellular and intracellular sides. previous studies have provided insight into the up-regulation of kir channel activity by extracellular k+ concentration. in contrast, extracellular mg2+ has been found to reduce the amplitude of the single-channel current at milimolar concentrations. however, little is ... | 2014 | 25350118 |
| differential expression of arid5b isoforms in xenopus laevis pronephros. | arid5b belongs to the arid family of transcription factors characterised by a helix-turn-helix motif- based dna-binding domain called arid (a-t rich interaction domain). in human, alternative splicing leads to long and short isoforms (isoform1 and 2, respectively) which differ in their n-terminal part. in this study, we report the cloning and expression pattern of xenopus laevis arid5b. we have isolated a full length cdna that shows homology with the human arid5b isoform1. furthermore, 5'race ex ... | 2014 | 25354457 |
| two different vestigial like 4 genes are differentially expressed during xenopus laevis development. | the vestigial gene (vg) was first characterized in drosophila and several homologues were identified in vertebrates and called vestigial like 1-4 (vgll1-4). vgll proteins interact with the transcription factors tef-1 and mef-2 through a conserved region called tondu (tdu). vgll4s are characterized by two tandem tdu domains which differentiate them from other members of the vestigial family. in xenopus two genes were identified as vgll4. our bioinformatic analysis demonstrated that these two gene ... | 2014 | 25354458 |
| transporters involved in renal excretion of n-carbamoylglutamate, an orphan drug to treat inborn n-acetylglutamate synthase deficiency. | inborn defects in n-acetylglutamate (nag) synthase (nags) cause a reduction of nag, an essential cofactor for the initiation of the urea cycle. as a consequence, blood ammonium concentrations are elevated, leading to severe neurological disorders. the orphan drug n-carbamoylglutamate (ncg; carbaglu), efficiently overcomes nags deficiency. however, not much is known about the transporters involved in the uptake, distribution, and elimination of the divalent organic anion ncg. organic anion-transp ... | 2014 | 25354943 |
| an adhesome comprising laminin, dystroglycan and myosin iia is required during notochord development in xenopus laevis. | dystroglycan (dg) is a transmembrane receptor for laminin that must be expressed at the right time and place in order to be involved in notochord morphogenesis. the function of dg was examined in xenopus laevis embryos by knockdown of dg and overexpression and replacement of the endogenous dg with a mutated form of the protein. this analysis revealed that dg is required for correct laminin assembly, for cell polarization during mediolateral intercalation and for proper differentiation of vacuole ... | 2014 | 25359726 |
| antennal-expressed ammonium transporters in the malaria vector mosquito anopheles gambiae. | the principal afrotropical malaria vector mosquito, anopheles gambiae remains a significant threat to human health. in this anthropophagic species, females detect and respond to a range of human-derived volatile kairomones such as ammonia, lactic acid, and other carboxylic acids in their quest for blood meals. while the molecular underpinnings of mosquito olfaction and host seeking are becoming better understood, many questions remain unanswered. in this study, we have identified and characteriz ... | 2014 | 25360676 |
| histone methyltransferase dot1l plays a role in postembryonic development in xenopus tropicalis. | histone methylations have been implicated to play important roles in diverse cellular processes. of particular interest is the methylation of histone h3k79, which is catalyzed by an evolutionarily conserved methyltransferase, disruptor of telomeric silencing (dot1)-like (dot1l). to investigate the role of dot1l during vertebrate development, we have generated a dot1l-specific transcription activator-like effector nuclease (talen) nuclease to knockdown endogenous dot1l in xenopus tropicalis, a di ... | 2015 | 25366346 |
| optogenetic control of apoptosis in targeted tissues of xenopus laevis embryos. | killerred (kr) is a recently discovered fluorescent protein that, when activated with green light, releases reactive oxygen species (ros) into the cytoplasm, triggering apoptosis in a kr-expressing cell. this property allows for the use of kr as a means of killing cells in an organism with great temporal and spatial specificity, while minimizing the nonspecific effects that can result from mechanical or chemical exposure damage techniques. such optogenetic control of cell death, and the resultin ... | 2014 | 25374461 |
| spak dependent regulation of peptide transporters pept1 and pept2. | spak (ste20-related proline/alanine-rich kinase) is a powerful regulator of renal tubular ion transport and blood pressure. moreover, spak contributes to the regulation of cell volume. little is known, however, about a role of spak in the regulation or organic solutes. the present study thus addressed the influence of spak on the peptide transporters pept1 and pept2. | 2014 | 25376088 |
| nucleotide bound to rab11a controls localization in rod cells but not interaction with rhodopsin. | precise vectorial transport of rhodopsin is essential for rod photoreceptor health and function. mutations that truncate or extend the c terminus of rhodopsin disrupt this transport, and lead to retinal degeneration and blindness in human patients and in mouse models. here we show that such mutations disrupt the binding of rhodopsin to the small gtpase rab11a. the rhodopsin-rab11a interaction is a direct binding interaction that does not depend on the nucleotide binding state of rab11a. expressi ... | 2014 | 25378153 |
| flow sensing in developing xenopus laevis is disrupted by visual cues and ototoxin exposure. | we explored how lateral line cues interact with visual cues to mediate flow sensing behaviors in the nocturnal developing frog, xenopus laevis, by exposing animals to current flows under different lighting conditions and after exposure to the ototoxin gentamicin. under dark conditions, xenopus tadpoles move downstream at the onset of current flow, then turn, and orient toward the direction of the flow with high accuracy. postmetamorphic froglets also exhibit positive rheotaxis but with less accu ... | 2015 | 25380559 |
| the virtual xenbase: transitioning an online bioinformatics resource to a private cloud. | as a model organism database, xenbase has been providing informatics and genomic data on xenopus (silurana) tropicalis and xenopus laevis frogs for more than a decade. the xenbase database contains curated, as well as community-contributed and automatically harvested literature, gene and genomic data. a gbrowse genome browser, a blast+ server and stock center support are available on the site. when this resource was first built, all software services and components in xenbase ran on a single phy ... | 2014 | 25380782 |
| development of the vertebrate tailbud. | the anatomical tailbud is a defining feature of all embryonic chordates, including vertebrates that do not end up with a morphological tail. due to its seamless continuity with trunk tissues, the tailbud is often overlooked as a mere extension of the body axis; however, the formation of the tail from the tailbud undoubtedly involves unique and distinct mechanisms for forming axial tissues, such as the secondary neurulation process that generates the tailbud-derived spinal cord. tailbud formation ... | 2016 | 25382697 |
| recruitment of gβγ controls the basal activity of g-protein coupled inwardly rectifying potassium (girk) channels: crucial role of distal c terminus of girk1. | the g-protein coupled inwardly rectifying potassium (girk, or kir3) channels are important mediators of inhibitory neurotransmission via activation of g-protein coupled receptors (gpcrs). girk channels are tetramers comprising combinations of subunits (girk1-4), activated by direct binding of the gβγ subunit of gi/o proteins. heterologously expressed girk1/2 exhibit high, gβγ-dependent basal currents (ibasal) and a modest activation by gpcr or coexpressed gβγ. inversely, the girk2 homotetramers ... | 2014 | 25384780 |
| carbon monoxide (co) is a novel inhibitor of connexin hemichannels. | hemichannels (hcs) are hexamers of connexins that can form gap-junction channels at points of cell contacts or "free hcs" at non-contacting regions. hcs are involved in paracrine and autocrine cell signaling, and under pathological conditions may induce and/or accelerate cell death. therefore, studies of hc regulation are of great significance. nitric oxide affects the activity of cx43 and cx46 hcs, whereas carbon monoxide (co), another gaseous transmitter, modulates the activity of several ion ... | 2014 | 25384983 |
| system l amino acid transporter lat1 accumulates o-(2-fluoroethyl)-l-tyrosine (fet). | o-(2-fluoroethyl)-l-tyrosine (fet) labeled with fluorine-18 is an important and specific tracer for diagnostics of glioblastoma via positron emission tomography (pet). however, the mechanism of its quite specific accumulation in tumor tissue has not been understood so far. in this work we demonstrate that [(3)h]l-tyrosine is primarily transported by the system l transporter lat1 in human ln229 glioblastoma cells. fet reduced tyrosine transport, suggesting that it shares the same uptake pathway. ... | 2015 | 25385314 |
| inflammation-induced reactivation of the ranavirus frog virus 3 in asymptomatic xenopus laevis. | natural infections of ectothermic vertebrates by ranaviruses (rv, family iridoviridae) are rapidly increasing, with an alarming expansion of rv tropism and resulting die-offs of numerous animal populations. notably, infection studies of the amphibian xenopus laevis with the ranavirus frog virus 3 (fv3) have revealed that although the adult frog immune system is efficient at controlling rv infections, residual quiescent virus can be detected in mononuclear phagocytes of otherwise asymptomatic ani ... | 2014 | 25390636 |
| hcn2 channels: a permanent open state and conductance changes. | hyperpolarization-activated cyclic nucleotide-gated (hcn) channels in the membranes of heart and brain cells can conduct na(+) and k(+) ions and activate between -30 and -120 mv. we express the α subunit of hcn2 channels in xenopus laevis oocytes and are confronted with two unexpected problems. first, we observe a rise in membrane conductance at resting potential proportional to the amount of expression. on activation to hyperpolarizing potentials, the instantaneous conductance rises in proporti ... | 2015 | 25391723 |
| phosphatidylinositol 4,5-bisphosphate degradation inhibits the na+/bicarbonate cotransporter nbce1-b and -c variants expressed in xenopus oocytes. | we previously reported that the phospholipid phosphatidylinositol 4,5-bisphosphate (pip2 ) directly stimulates heterologously expressed electrogenic na(+)/bicarbonate cotransporter nbce1-a in an excised macropatch from the xenopus oocyte, and indirectly stimulates nbce1-b and -c in the intact oocyte primarily through inositol 1,4,5-trisphosphate/ca(2+). in the current study, we expand on a previous observation that pip2 may also directly stimulate nbce1 in the intact oocyte. in this study on ooc ... | 2015 | 25398525 |
| the olfactory system as a model to study axonal growth patterns and morphology in vivo. | the olfactory system has the unusual capacity to generate new neurons throughout the lifetime of an organism. olfactory stem cells in the basal portion of the olfactory epithelium continuously give rise to new sensory neurons that extend their axons into the olfactory bulb, where they face the challenge to integrate into existing circuitry. because of this particular feature, the olfactory system represents a unique opportunity to monitor axonal wiring and guidance, and to investigate synapse fo ... | 2014 | 25406975 |
| assessment of natural variation in the first pore domain of the tomato hkt1;2 transporter and characterization of mutated versions of slhkt1;2 expressed in xenopus laevis oocytes and via complementation of the salt sensitive athkt1;1 mutant. | single nucleotide polymorphisms (snps) within the coding sequence of hkt transporters are important for the functioning of these transporters in several plant species. to unravel the functioning of hkt transporters analysis of natural variation and multiple site-directed mutations studies are crucial. also the in vivo functioning of hkt proteins, via complementation studies performed with athkt1;1 plants, could provide essential information about these transporters. in this work, we analyzed the ... | 2014 | 25408697 |
| diurnal variation of tight junction integrity associates inversely with matrix metalloproteinase expression in xenopus laevis corneal epithelium: implications for circadian regulation of homeostatic surface cell desquamation. | the corneal epithelium provides a protective barrier against pathogen entrance and abrasive forces, largely due to the intercellular junctional complexes between neighboring cells. after a prescribed duration at the corneal surface, tight junctions between squamous surface cells must be disrupted to enable them to desquamate as a component of the tissue homeostatic renewal. we hypothesize that matrix metalloproteinase (mmps) are secreted by corneal epithelial cells and cleave intercellular junct ... | 2014 | 25412440 |
| protocadherin-9 involvement in retinal development in xenopus laevis. | biological roles of most protocadherins (pcdhs) are a largely unsolved problem. therefore, we cloned cdna for xenopus laevis protocadherin-9 and characterized its properties to elucidate the role. the deduced amino acid sequence was highly homologous to those of mammalian protocadherin-9 s. x. laevis protocadherin-9 expressed from the cdna in l cells showed basic properties similar to those of mammalian pcdhs. expression of x. laevis protocadherin-9 was first detected in stage-31 embryos and inc ... | 2015 | 25414271 |
| identifying direct targets of transcription factor rfx2 that coordinate ciliogenesis and cell movement. | recently, using the frog xenopus laevis as a model system, we showed that transcription factor rfx2 coordinates many genes involved in ciliogenesis and cell movement in multiciliated cells (chung et al., 2014). to our knowledge, it was the first paper to utilize the genomic resources, including genome sequences and interim gene annotations, from the ongoing xenopus laevis genome project. for researchers who are interested in the application of genomics and systems biology approaches in xenopus s ... | 2014 | 25419512 |
| mutations in the voltage-gated potassium channel gene kcnh1 cause temple-baraitser syndrome and epilepsy. | temple-baraitser syndrome (tbs) is a multisystem developmental disorder characterized by intellectual disability, epilepsy, and hypoplasia or aplasia of the nails of the thumb and great toe. here we report damaging de novo mutations in kcnh1 (encoding a protein called ether à go-go, eag1 or kv10.1), a voltage-gated potassium channel that is predominantly expressed in the central nervous system (cns), in six individuals with tbs. characterization of the mutant channels in both xenopus laevis oocy ... | 2015 | 25420144 |
| dynein light intermediate chains maintain spindle bipolarity by functioning in centriole cohesion. | cytoplasmic dynein 1 (dynein) is a minus end-directed microtubule motor protein with many cellular functions, including during cell division. the role of the light intermediate chains (lics; dync1li1 and 2) within the complex is poorly understood. in this paper, we have used small interfering rnas or morpholino oligonucleotides to deplete the lics in human cell lines and xenopus laevis early embryos to dissect the lics' role in cell division. we show that although dynein lacking lics drives micr ... | 2014 | 25422374 |
| transcriptional changes in african clawed frogs (xenopus laevis) exposed to 17α-ethynylestradiol during early development. | although the past two decades have witnessed a significant increase in the number of studies investigating effects of estrogenic chemicals on amphibians, to date little is known about specific molecular interactions of estrogens with the hypothalamus-pituitary-gonadal-hepatic axis in developing amphibians. here, tissue-specific functional sets of genes, derived previously from studies of fishes exposed to endocrine active chemicals, were evaluated in xenopus laevis exposed to 17α-ethynylestradio ... | 2015 | 25427717 |
| evidence from peptidomic analysis of skin secretions that allopatric populations of xenopus gilli (anura:pipidae) constitute distinct lineages. | the international union for conservation of nature (iucn) endangered cape platanna xenopus gilli inhabits disjunct ranges at the tip of cape peninsula and near the town of kleinmond on opposite sides of false bay in the extreme southwest of africa. peptidomic analysis of host-defense peptides in norepinephrine-stimulated skin secretions from frogs from the cape peninsula range resulted in the identification of two magainins, two peptide glycine-leucine-amide (pgla) peptides, two xenopsin-precurs ... | 2015 | 25433327 |
| [follicular cells of the amphibian ovary: origin, structure, and functions]. | formation of the follicular envelopes surrounding oocytes in the developing ovary and their subsequent morphological differentiation go hand-in-hand with succession of the steroidogenesis stages, arrest of meiosis and its maintenance, establishment of the conditions necessary for vitellogenesis, oocyte growth, and maturation. metabolites are exchanged via gap junctions and receptor-mediated transport through the perioocytic space. the ion transport in follicular cells (fcs) regulates the plasma ... | 2016 | 25434201 |
| gene expression pattern of kifc3 during spermatogenesis of the skink eumeces chinensis. | kinesin superfamily is a class of microtubule-dependent motors that play crucial roles in acrosome biogenesis, nuclear reshaping and flagellum formation during spermiogenesis. we have cloned kinesin-like gene kifc3 (termed ec-kifc3) from the total rna of the testis of the skink eumeces chinensis. the cdna sequence of ec-kifc3 had a full-length of 3033bp, including a 260bp 5'-untranslated region (5'utr), a 445bp 3'-untranslated region (3'utr) and an open reading frame that encoded a 775-amino-aci ... | 2015 | 25434495 |
| evolutionary innovation and conservation in the embryonic derivation of the vertebrate skull. | development of the vertebrate skull has been studied intensively for more than 150 years, yet many essential features remain unresolved. one such feature is the extent to which embryonic derivation of individual bones is evolutionarily conserved or labile. we perform long-term fate mapping using gfp-transgenic axolotl and xenopus laevis to document the contribution of individual cranial neural crest streams to the osteocranium in these amphibians. here we show that the axolotl pattern is strikin ... | 2014 | 25434971 |
| xenopus laevis fgf receptor substrate 3 (xfrs3) is important for eye development and mediates pax6 expression in lens placode through its shp2-binding sites. | members of the fibroblast growth factor (fgf) family play important roles during various developmental processes including eye development. frs (fgf receptor substrate) proteins bind to fgfr and serve as adapters for coordinated assembly of multi-protein complexes involved in ras/mapk and pi3 kinase/akt pathways. here, we identified xenopus laevis frs3 (xfrs3), a homolog of vertebrate frs3, and investigated its roles during embryogenesis. xfrs3 is expressed maternally and zygotically with specif ... | 2015 | 25446028 |
| a gene expression map of the larval xenopus laevis head reveals developmental changes underlying the evolution of new skeletal elements. | the morphology of the vertebrate head skeleton is highly plastic, with the number, size, shape, and position of its components varying dramatically between groups. while this evolutionary flexibility has been key to vertebrate success, its developmental and genetic bases are poorly understood. the larval head skeleton of the frog xenopus laevis possesses a unique combination of ancestral tetrapod features and anuran-specific novelties. we built a detailed gene expression map of the head mesenchy ... | 2015 | 25446275 |
| biological and biochemical properties of two xenopus laevis n-acetylgalactosaminyltransferases with contrasting roles in embryogenesis. | the biosynthesis of mucin-type o-linked glycans in animals is initiated by members of the large family of polypeptide n-acetylgalactosaminyltransferases (galnac-ts), which play important roles in embryogenesis, organogenesis, adult tissue homeostasis and carcinogenesis. until now, the mammalian forms of these enzymes have been the best characterized. however, two n-acetylgalactosaminyltransferases (xgalnac-t6 and xgalnac-t16) from the african clawed frog (xenopus laevis), which are most homologo ... | 2015 | 25447273 |
| baroreflex function in anurans from different environments. | anurans from terrestrial environments have an enhanced ability to maintain mean arterial blood pressure (p(m)) through lymph mobilization in response to desiccation or hemorrhage compared with semiaquatic or aquatic species. because short term blood pressure homeostasis is regulated by arterial baroreceptors, we compared baroreflex function in three species of anurans that span a range of environments, dehydration tolerance and an ability to maintain p(m) with dehydration and hemorrhage. the car ... | 2015 | 25447736 |
| changes in gastric sodium-iodide symporter (nis) activity are associated with differences in thyroid gland sensitivity to perchlorate during metamorphosis. | we investigated stage-dependent changes in sensitivity of the thyroid gland to perchlorate during development of african clawed frog tadpoles (xenopus laevis) in relation to non-thyroidal iodide transporting tissues. perchlorate-induced increases in thyroid follicle cell size and colloid depletion were blunted when exposures began at nieuwkoop-faber (nf) stage 55 compared to when exposures began at nf stages 49 or 1-10. to determine if the development of other iodide transporting tissues may con ... | 2015 | 25448256 |
| cellular characterization of thrombocytes in xenopus laevis with specific monoclonal antibodies. | platelets are produced from megakaryocytes (mks) in the bone marrow. in contrast, most nonmammalian vertebrates have nucleated and spindle-shaped thrombocytes instead of platelets in their circulatory systems, and the presence of mks as thrombocyte progenitors has not been verified. in developing a new animal model in adult african clawed frog (xenopus laevis), we needed to distinguish nucleated thrombocytes and their progenitors from other blood cells, because the cellular morphology of activat ... | 2015 | 25448492 |
| a method for using direct injection of plasmid dna to study cis-regulatory element activity in f0 xenopus embryos and tadpoles. | the ability to express exogenous reporter genes in intact, externally developing embryos, such as xenopus, is a powerful tool for characterizing the activity of cis-regulatory gene elements during development. although methods exist for generating transgenic xenopus lines, more simplified methods for use with f0 animals would significantly speed the characterization of these elements. we discovered that injecting 2-cell stage embryos with a plasmid bearing a ϕc31 integrase-targeted attb element ... | 2015 | 25448690 |
| a novel method for inducing nerve growth via modulation of host resting potential: gap junction-mediated and serotonergic signaling mechanisms. | a major goal of regenerative medicine is to restore the function of damaged or missing organs through the implantation of bioengineered or donor-derived components. it is necessary to understand the signals and cues necessary for implanted structures to innervate the host, as organs devoid of neural connections provide little benefit to the patient. while developmental studies have identified neuronal pathfinding molecules required for proper patterning during embryogenesis, strategies to initia ... | 2015 | 25449797 |
| differential regulation of the glutamate transporters glt-1 and glast by gsk3β. | the glutamate transporters glast and glt-1 are mainly expressed in glial cells and regulate glutamate levels in the synapses. glast and glt-1 are the targets of several signaling pathways. in this study we explore the possible functional interaction between these transporters and gsk3β. this kinase is involved in multiple cellular processes including neuronal development and synaptic plasticity. to evaluate whether glt-1 and glast were regulated by gsk3β, we coexpressed these proteins in heterol ... | 2014 | 25454285 |
| molecular characterization and mrna expression of ribosomal protein l8 in rana nigromaculata during development and under exposure to hormones. | like xenopus laevis, some species of the rana genus are also used to study endocrine disrupting chemicals (edcs). although ribosomal protein l8 (rpl8) is the most-used reference gene for analyzing gene expression by quantitative reverse transcription polymerase chain reaction in rana, its suitability as the reference gene has never been validated in any species of the rana genus. we characterized rpl8 cdna in rana nigromaculata, a promising native species in east asia for assaying endocrine disr ... | 2014 | 25458689 |
| distinct patterns of compartmentalization and proteolytic stability of pde6c mutants linked to achromatopsia. | phosphodiesterase-6 (pde6) is an essential effector enzyme in vertebrate photoreceptor cells. mutations in rod and cone pde6 cause recessive retinitis pigmentosa and achromatopsia, respectively. the mechanisms of missense pde6 mutations underlying severe visual disorders are poorly understood. to probe these mechanisms, we expressed seven known missense mutants of cone pde6c in rods of transgenic xenopus laevis and examined their stability and compartmentalization. pde6c proteins with mutations ... | 2015 | 25461672 |
| host-defense peptides from skin secretions of fraser's clawed frog xenopus fraseri (pipidae): further insight into the evolutionary history of the xenopodinae. | peptidomic analysis of norepinephrine-stimulated skin secretions of the tetraploid frog xenopus fraseri boulenger, 1905 (pipidae) led to identification of 13 host-defense peptides. the primary structures of the peptides demonstrate that they belong to the magainin (3 peptides), peptide glycine-leucine-amide, pgla (4 peptides), and xenopsin-precursor fragment, xpf (2 peptides) families, first identified in xenopus laevis, together with caerulein precursor fragment-related peptides, cpf-rp (4 pept ... | 2014 | 25463057 |
| distinct features of cap binding by eif4e1b proteins. | eif4e1b, closely related to the canonical translation initiation factor 4e (eif4e1a), cap-binding protein is highly expressed in mouse, xenopus and zebrafish oocytes. we have previously characterized eif4e1b as a component of the cpeb mrnp translation repressor complex along with the eif4e-binding protein 4e-transporter, the xp54/ddx6 rna helicase and additional rna-binding proteins. eif4e1b exhibited only very weak interactions with m(7)gtp-sepharose and, rather than binding eif4g, interacted w ... | 2014 | 25463438 |
| calcium-dependent neuroepithelial contractions expel damaged cells from the developing brain. | both developing and adult organisms need efficient strategies for wound repair. in adult mammals, wounding triggers an inflammatory response that can exacerbate tissue injury and lead to scarring. in contrast, embryonic wounds heal quickly and with minimal inflammation, but how this is achieved remains incompletely understood. using in vivo imaging in the developing brain of xenopus laevis, we show that atp release from damaged cells and subsequent activation of purinergic receptors induce long- ... | 2014 | 25468753 |
| microtubule nucleation remote from centrosomes may explain how asters span large cells. | a major challenge in cell biology is to understand how nanometer-sized molecules can organize micrometer-sized cells in space and time. one solution in many animal cells is a radial array of microtubules called an aster, which is nucleated by a central organizing center and spans the entire cytoplasm. frog (here xenopus laevis) embryos are more than 1 mm in diameter and divide with a defined geometry every 30 min. like smaller cells, they are organized by asters, which grow, interact, and move t ... | 2014 | 25468969 |
| cellular and molecular targets of benzo[a]pyrene and metal toxicity in xenopus laevis embryos and in hep g2 cells. | this paper describes the use of two in vitro systems (stage 35 xenopus laevis embryos and the human hepatoblastoma cell line, hep g2) to study effects of some environmental contaminants (benzo[a]pyrene, copper and zinc), which are representative of chemicals with different cell targets and mechanisms of action. the ability to activate benzo[a[pyrene and to metabolise it with the cytochrome p4501a isozyme were demonstrated in both in vitro systems by assessing the formation of water-soluble and p ... | 2014 | 25470671 |
| essential amino acid transporter lat4 (slc43a2) is required for mouse development. | amino acid (aa) uniporter lat4 (slc43a2) mediates facilitated diffusion of branched-chain aas, methionine and phenylalanine, although its physiological role and subcellular localization are not known. we report that slc43a2 knockout mice were born at expected mendelian frequency but displayed an ∼10% intrauterine growth retardation and low amniotic fluid aas, suggesting defective transplacental transport. postnatal growth was strongly reduced, with premature death occurring within 9 days such th ... | 2015 | 25480797 |
| validation of the sperm chromatin dispersion (scd) test in the amphibian xenopus laevis using in situ nick translation and comet assay. | the integrity of sperm dna is becoming increasingly recognised as an important parameter of semen quality, but there are no published reports of this procedure for any amphibian. the primary aim of this study was to apply a modified sperm chromatin dispersion (scd) test (halomax) to an amphibian sperm model (african clawed frog; xenopus laevis) and to validate the assay against in situ nick translation (isnt) and the double-comet assay procedure. inactivated spermatozoa were collected from fresh ... | 2015 | 25482041 |
| n-glycans in xenopus laevis testis characterised by lectin histochemistry. | analysis of glycan chains of glycoconjugates is difficult because of their considerable variety. despite this, several functional roles for these glycans have been reported. n-glycans are oligosaccharides linked to asparagine residues of proteins. they are synthesised in the endoplasmic reticulum (er) in a unique way, and later modified in both the er and golgi apparatus, developing different oligosaccharide chains. an essential role for complex n-glycans in mammalian spermatogenesis has been re ... | 2016 | 25482090 |
| aminolevulinate synthase 2 mediates erythrocyte differentiation by regulating larval globin expression during xenopus primary hematopoiesis. | hemoglobin synthesis by erythrocytes continues throughout a vertebrate's lifetime. the mechanism of mammalian heme synthesis has been studied for many years; aminolevulinate synthase 2 (alas2), a heme synthetase, is associated with x-linked dominant protoporphyria in humans. amphibian and mammalian blood cells differ, but little is known about amphibian embryonic hemoglobin synthesis. we investigated the function of the xenopus alas2 gene (xalas2) in primitive amphibian erythrocytes and found th ... | 2015 | 25482442 |
| nuclear size scaling during xenopus early development contributes to midblastula transition timing. | early xenopus laevis embryogenesis is a robust system for investigating mechanisms of developmental timing. after a series of rapid cell divisions with concomitant reductions in cell size, the first major developmental transition is the midblastula transition (mbt), when zygotic transcription begins and cell cycles elongate. whereas the maintenance of a constant nuclear-to-cytoplasmic (n/c) volume ratio is a conserved cellular property, it has long been recognized that the n/c volume ratio chang ... | 2015 | 25484296 |
| evolutionary diversification of mcm3 genes in xenopus laevis and danio rerio. | embryonic cell cycles of amphibians are rapid and lack zygotic transcription and checkpoint control. at the mid-blastula transition, zygotic transcription is initiated and cell divisions become asynchronous. several cell cycle-related amphibian genes retain 2 distinct forms, maternal and zygotic, but little is known about the functional differences between these 2 forms of proteins. the minichromosome maintenance (mcm) 2-7 complex, consisting of 6 mcm proteins, plays a central role in the regula ... | 2014 | 25485507 |
| distinct action of the α-glucosidase inhibitor miglitol on sglt3, enteroendocrine cells, and glp1 secretion. | oral ingestion of carbohydrate triggers glucagon-like peptide 1 (glp1) secretion, but the molecular mechanism remains elusive. by measuring glp1 concentrations in murine portal vein, we found that the atp-sensitive k(+) (katp) channel is not essential for glucose-induced glp1 secretion from enteroendocrine l cells, while the sodium-glucose co-transporter 1 (sglt1) is required, at least in the early phase (5 min) of secretion. by contrast, co-administration of the α-glucosidase inhibitor (α-gi) m ... | 2015 | 25486965 |
| brain-derived neurotrophic factor (bdnf) expression in normal and regenerating olfactory epithelium of xenopus laevis. | olfactory epithelium has the capability to continuously regenerate olfactory receptor neurons throughout life. adult neurogenesis results from proliferation and differentiation of neural stem cells, and consequently, olfactory neuroepithelium offers an excellent opportunity to study neural regeneration and the factors involved in the maintenance and regeneration of all their cell types. we analyzed the expression of bdnf in the olfactory system under normal physiological conditions as well as du ... | 2015 | 25488259 |
| apkc phosphorylates p27xic1, providing a mechanistic link between apicobasal polarity and cell-cycle control. | during the development of the nervous system, apicobasally polarized stem cells are characterized by a shorter cell cycle than nonpolar progenitors, leading to a lower differentiation potential of these cells. however, how polarization might be directly linked to the kinetics of the cell cycle is not understood. here, we report that apicobasally polarized neuroepithelial cells in xenopus laevis have a shorter cell cycle than nonpolar progenitors, consistent with mammalian systems. we show that t ... | 2014 | 25490266 |
| methylmercury exposure during early xenopus laevis development affects cell proliferation and death but not neural progenitor specification. | methylmercury (mehg) is a widespread environmental toxin that preferentially and adversely affects developing organisms. to investigate the impact of mehg toxicity on the formation of the vertebrate nervous system at physiologically relevant concentrations, we designed a graded phenotype scale for evaluating xenopus laevis embryos exposed to mehg in solution. embryos displayed a range of abnormalities in response to mehg, particularly in brain development, which is influenced by both mehg concen ... | 2017 | 25496965 |
| kcnip1 a ca²⁺-dependent transcriptional repressor regulates the size of the neural plate in xenopus. | in amphibian embryos, our previous work has demonstrated that calcium transients occurring in the dorsal ectoderm at the onset of gastrulation are necessary and sufficient to engage the ectodermal cells into a neural fate by inducing neural specific genes. some of these genes are direct targets of calcium. here we search for a direct transcriptional mechanism by which calcium signals are acting. the only known mechanism responsible for a direct action of calcium on gene transcription involves an ... | 2015 | 25499267 |
| ntpdase2 and the p2y1 receptor are not required for mammalian eye formation. | eye formation in vertebrates is controlled by a conserved pattern of molecular networks. homeobox transcription factors are crucially involved in the establishment and maintenance of the retina. a previous study of massé et al. (nature, 449: 1058-62, 2007) using morpholino knockdown identified the ectonucleotidase ntpdase2 and the p2y1 receptor as essential elements for eye formation in embryos of the clawed frog xenopus laevis. in order to investigate whether a similarly essential mechanism wou ... | 2015 | 25504514 |
| subcellular metabolite and lipid analysis of xenopus laevis eggs by laesi mass spectrometry. | xenopus laevis eggs are used as a biological model system for studying fertilization and early embryonic development in vertebrates. most methods used for their molecular analysis require elaborate sample preparation including separate protocols for the water soluble and lipid components. in this study, laser ablation electrospray ionization (laesi), an ambient ionization technique, was used for direct mass spectrometric analysis of x. laevis eggs and early stage embryos up to five cleavage cycl ... | 2014 | 25506922 |
| pre-meiotic transformation of germplasm-related structures during male gamete differentiation in xenopus laevis. | to highlight the ultrastructural features of transformation occurring with germplasm-related structures (gprs), the spermatogenic cells of xenopus laevis were studied by transmission electron microscopy and quantitative analysis. it was determined that in spermatogonia and spermatocytes, the compact germinal granules underwent fragmentation into particles comparable with inter-mitochondrial cement (imc). fragments of imc agglutinated some cell mitochondria and resulted in the creation of mitocho ... | 2016 | 25511532 |
| vertical signalling involves transmission of hox information from gastrula mesoderm to neurectoderm. | development and patterning of neural tissue in the vertebrate embryo involves a set of molecules and processes whose relationships are not fully understood. classical embryology revealed a remarkable phenomenon known as vertical signalling, a gastrulation stage mechanism that copies anterior-posterior positional information from mesoderm to prospective neural tissue. vertical signalling mediates unambiguous copying of complex information from one tissue layer to another. in this study, we report ... | 2014 | 25514127 |
| comparative pharmacology of flatworm and roundworm glutamate-gated chloride channels: implications for potential anthelmintics. | pharmacological targeting of glutamate-gated chloride channels (glucls) is a potent anthelmintic strategy, evidenced by macrocyclic lactones that eliminate numerous roundworm infections by activating roundworm glucls. given the recent identification of flatworm glucls and the urgent need for drugs against schistosomiasis, flatworm glucls should be evaluated as potential anthelmintic targets. this study sought to identify agonists or modulators of one such glucl, smglucl-2 from the parasitic flat ... | 2014 | 25516835 |
| evidence for multiple, distinct adar-containing complexes in xenopus laevis. | adar (adenosine deaminase acting on rna) is an rna-editing enzyme present in most metazoans that converts adenosines in double-stranded rna targets into inosines. although the rna targets of adar-mediated editing have been extensively cataloged, our understanding of the cellular function of such editing remains incomplete. we report that long, double-stranded rna added to xenopus laevis egg extract is incorporated into an adar-containing complex whose protein components resemble those of stress ... | 2015 | 25519486 |
| characterization of the ca2+-gated and voltage-dependent k+-channel slo-1 of nematodes and its interaction with emodepside. | the cyclooctadepsipeptide emodepside and its parent compound pf1022a are broad-spectrum nematicidal drugs which are able to eliminate nematodes resistant to other anthelmintics. the mode of action of cyclooctadepsipeptides is only partially understood, but involves the latrophilin lat-1 receptor and the voltage- and calcium-activated potassium channel slo-1. genetic evidence suggests that emodepside exerts its anthelmintic activity predominantly through slo-1. indeed, slo-1 deficient caenorhabdi ... | 2014 | 25521608 |
| direct nkx2-5 transcriptional repression of isl1 controls cardiomyocyte subtype identity. | during cardiogenesis, most myocytes arise from cardiac progenitors expressing the transcription factors isl1 and nkx2-5. here, we show that a direct repression of isl1 by nkx2-5 is necessary for proper development of the ventricular myocardial lineage. overexpression of nkx2-5 in mouse embryonic stem cells (escs) delayed specification of cardiac progenitors and inhibited expression of isl1 and its downstream targets in isl1(+) precursors. embryos deficient for nkx2-5 in the isl1(+) lineage faile ... | 2015 | 25524439 |
| structural requirements in the transmembrane domain of glic revealed by incorporation of noncanonical histidine analogs. | the cyanobacterial pentameric ligand-gated ion channel glic, a homolog of the cys-loop receptor superfamily, has provided useful structural and functional information about its eukaryotic counterparts. x-ray diffraction data and site-directed mutagenesis have previously implicated a transmembrane histidine residue (his234) as essential for channel function. here, we investigated the role of his234 via synthesis and incorporation of histidine analogs and α-hydroxy acids using in vivo nonsense sup ... | 2014 | 25525989 |
| pancreatic carcinoma in an african clawed frog (xenopus laevis). | this report describes the histologic features of a pancreatic carcinoma in an adult female african clawed frog (xenopus laevis). the animal was found to be in poor body condition and subsequently euthanized for a complete necropsy. histologically, the pancreas was effaced by packets of polyhedral cells consistent with a pancreatic islet cell carcinoma. metastatic disease was not identified. pancreatic tumors are uncommon in amphibians, and this report is the first to describe a pancreatic carcin ... | 2014 | 25527022 |
| chronic sublethal exposure to silver nanoparticles disrupts thyroid hormone signaling during xenopus laevis metamorphosis. | nanoparticles (nps) are engineered in the nanoscale (<100 nm) to have unique physico-chemical properties from their bulk counterparts. nanosilver particles (agnps) are the most prevalent nps in consumer products due to their strong antimicrobial action. while agnp toxicity at high concentrations has been thoroughly investigated, the sublethal effects at or below regulatory guidelines are relatively unknown. amphibian metamorphosis is mediated by thyroid hormone (th), and initial studies with bul ... | 2015 | 25531432 |
| negative regulation of the creatine transporter slc6a8 by spak and osr1. | transport regulation involves several kinases including spak (sps1-related proline/alanine-rich kinase) and osr1 (oxidative stress-responsive kinase 1), which are under control of wnk (with-no-k[lys]) kinases. the present study explored whether spak and/or osr1 participate in the regulation of the creatine transporter creat (slc6a8), which accomplishes na+ coupled cellular uptake of creatine in several tissues including kidney, intestine, heart, skeletal muscle and brain. | 2014 | 25531585 |
| the effect of 900 and 1800 mhz gsm-like radiofrequency irradiation and nicotine sulfate administration on the embryonic development of xenopus laevis. | the aim of this study was to investigate the effects of gsm-like radiofrequency electromagnetic radiation (rf emr) and nicotine sulfate (ns) exposure on xenopus embryonic development.the developmental effects of gsm-like rf-emr (900-1800 mhz, at a sar value of 1w/kg and ns on xenopus laevis embryos were investigated). following the application of radiofrequency radiation and/or ns administration, the embryos were closely examined in order to determine their possible teratogenic effects. xenopus ... | 2015 | 25531835 |
| human intestine luminal ace2 and amino acid transporter expression increased by ace-inhibitors. | sodium-dependent neutral amino acid transporter b(0)at1 (slc6a19) and imino acid (proline) transporter sit1 (slc6a20) are expressed at the luminal membrane of small intestine enterocytes and proximal tubule kidney cells where they exert key functions for amino acid (re)absorption as documented by their role in hartnup disorder and iminoglycinuria, respectively. expression of b(0)at1 was shown in rodent intestine to depend on the presence of the carboxypeptidase angiotensin-converting enzyme 2 (a ... | 2015 | 25534429 |
| characterization of tweety gene (ttyh1-3) expression in xenopus laevis during embryonic development. | the tweety family of genes encodes large-conductance chloride channels and has been implicated in a wide array of cellular processes including cell division, cell adhesion, regulation of calcium activity, and tumorigenesis, particularly in neuronal cells. however, their expression patterns during early development remain largely unknown. here, we describe the spatial and temporal patterning of ttyh1, ttyh2, and ttyh3 in xenopus laevis during early embryonic development. ttyh1 and ttyh3 are initi ... | 2015 | 25541457 |
| phylogenetic and structural analysis of the phospholipase a2 gene family in vertebrates. | the phospholipase a (pla)2 family is the most complex gene family of phospholipases and plays a crucial role in a number of physiological activities. however, the phylogenetic background of the pla2 gene family and the amino acid residues of the pla2g7 gene following positive selection gene remain undetermined. in this study, we downloaded 49 genomic data sets of pla from different species, including the human, house mouse, norway rat, pig, dog, chicken, cattle, african clawed frog, sumatran ora ... | 2015 | 25543670 |
| transmembrane signal transduction in oocyte maturation and fertilization: focusing on xenopus laevis as a model animal. | fertilization is a cell biological phenomenon of crucial importance for the birth of new life in a variety of multicellular and sexual reproduction species such as algae, animal and plants. fertilization involves a sequence of events, in which the female gamete "egg" and the male gamete "spermatozoon (sperm)" develop, acquire their functions, meet and fuse with each other, to initiate embryonic and zygotic development. here, it will be briefly reviewed how oocyte cytoplasmic components are orche ... | 2014 | 25546390 |
| effects on channel properties and induction of cell death induced by c-terminal truncations of pannexin1 depend on domain length. | pannexin1 (panx1) is an integral membrane protein and known to form multifunctional hexameric channels. recently, panx1 was identified to be responsible for the release of atp and utp from apoptotic cells after site-specific proteolysis by caspases 3/7. cleavage at the carboxy-terminal (ct) position aa 376-379 irreversibly opens human panx1 channels and leads to the release of the respective nucleotides resulting in recruitment of macrophages and in subsequent activation of the immunologic respo ... | 2015 | 25567359 |
| interactive effects of ultraviolet-b radiation and pesticide exposure on dna photo-adduct accumulation and expression of dna damage and repair genes in xenopus laevis embryos. | pesticide use and ultraviolet-b (uvb) radiation have both been suggested to adversely affect amphibians; however, little is known about their interactive effects. one potential adverse interaction could involve pesticide-induced dysregulation of dna repair pathways, resulting in greater numbers of dna photo-adducts from uvb exposure. in the present study, we investigated the interactive effects of uvb radiation and two common pesticides (endosulfan and α-cypermethrin) on induction of dna photo-a ... | 2015 | 25569846 |
| pan-african phylogeography of a model organism, the african clawed frog 'xenopus laevis'. | the african clawed frog xenopus laevis has a large native distribution over much of sub-saharan africa and is a model organism for research, a proposed disease vector, and an invasive species. despite its prominent role in research and abundance in nature, surprisingly little is known about the phylogeography and evolutionary history of this group. here, we report an analysis of molecular variation of this clade based on 17 loci (one mitochondrial, 16 nuclear) in up to 159 individuals sampled th ... | 2015 | 25583226 |
| trpp2-dependent ca2+ signaling in dorso-lateral mesoderm is required for kidney field establishment in xenopus. | in xenopus laevis embryos, kidney field specification is dependent on retinoic acid (ra) and coincides with a dramatic increase of ca(2+) transients, but the role of ca(2+) signaling in the kidney field is unknown. here, we identify trpp2, a member of the transient receptor potential (trp) superfamily of channel proteins encoded by the pkd2 gene, as a central component of ca(2+) signaling in the kidney field. trpp2 is strongly expressed at the plasma membrane where it might regulate extracellula ... | 2015 | 25588842 |
| homodimeric anoctamin-1, but not homodimeric anoctamin-6, is activated by calcium increases mediated by the p2y1 and p2x7 receptors. | the p2x7 receptor (p2x7r) is a ligand-gated ion channel that conducts na(+), k(+), and ca(2+) when activated by extracellular atp. in various cell types, such as secretory epithelia, the p2x7r is co-expressed with ca(2+)-dependent cl(-) channels of the tmem16/anoctamin family. here, we studied whether the p2x7r and tmem16a/anoctamin-1 (ano1) or tmem16f/anoctamin-6 (ano6) interact functionally and physically, using oocytes of xenopus laevis and ambystoma mexicanum (axolotl) for heterologous expre ... | 2015 | 25592660 |
| structural analysis of dopamine- and amphetamine-induced depolarization currents in the human dopamine transporter. | amphetamine (amph) induces depolarizing currents through the human dopamine transporter (hdat). recently we discovered that the s(+) enantiomer of amph induces a current through hdat that persists long after its removal from the external milieu. the persistent current is less prominent for r(-)amph and essentially absent for dopamine (da)-induced currents. related agents such as methamphetamine also exhibit persistent currents, which are present in both frog oocyte and mammalian hek expression s ... | 2015 | 25594379 |
| highly efficient gene knockout by injection of talen mrnas into oocytes and host transfer in xenopus laevis. | zinc-finger nucleases, transcription activator-like effector nucleases (talens) and the crispr/cas (clustered regularly interspaced short palindromic repeats/crispr-associated proteins) system are potentially powerful tools for producing tailor-made knockout animals. however, their mutagenic activity is not high enough to induce mutations at all loci of a target gene throughout an entire tadpole. in this study, we present a highly efficient method for introducing gene modifications at almost all ... | 2015 | 25596277 |
| semi-solid tumor model in xenopus laevis/gilli cloned tadpoles for intravital study of neovascularization, immune cells and melanophore infiltration. | tumors have the ability to grow as a self-sustaining entity within the body. this autonomy is in part accomplished by the tumor cells ability to induce the formation of new blood vessels (angiogenesis) and by controlling cell trafficking inside the tumor mass. these abilities greatly reduce the efficacy of many cancer therapies and pose challenges for the development of more effective cancer treatments. hence, there is a need for animal models suitable for direct microscopy observation of blood ... | 2015 | 25601449 |
| discovery of a novel general anesthetic chemotype using high-throughput screening. | the development of novel anesthetics has historically been a process of combined serendipity and empiricism, with most recent new anesthetics developed via modification of existing anesthetic structures. | 2015 | 25603205 |
| atnpf5.5, a nitrate transporter affecting nitrogen accumulation in arabidopsis embryo. | dipeptide (leu-leu) and nitrate transport activities of 26 arabidopsis npf (nrt1/ptr family) proteins were screened in saccharomyces cerevisiae and xenopus laevis oocytes, respectively. dipeptide transport activity has been confirmed for 2 already known dipeptide transporters (atnpf8.1 and atnpf8.3) but none of the other tested npfs displays dipeptide transport. the nitrate transport screen resulted in the identification of two new nitrate transporters, atnpf5.5 and atnpf5.10. the localization o ... | 2015 | 25608465 |
| the effect of long-term corticosterone treatment on blood cell differentials and function in laboratory and wild-caught amphibian models. | the effect of long-term stress on amphibian immunity is not well understood. we modeled a long-term endocrine stress scenario by elevating plasma corticosterone in two species of amphibians and examined effects on white blood cell differentials and innate immune activity. plasma corticosterone was elevated in american bullfrogs (lithobates catesbeianus) by surgically implanting corticosterone capsules and in african clawed frogs (xenopus laevis) by immersion in corticosterone-treated water. to p ... | 2015 | 25616196 |
| temporal and spatial expression analysis of peripheral myelin protein 22 (pmp22) in developing xenopus. | peripheral myelin protein 22 (pmp22), a member of the junction protein family claudin/emp/pmp22, contributes to the formation and maintenance of myelin sheaths in the peripheral nervous system. apart from the establishment and maintenance of peripheral nerves, pmp22 and its family member have also participated in a broad range of more general processes including cell cycle regulation and apoptosis during development. pmp22 has been identified from several vertebrate species including mouse, huma ... | 2015 | 25616247 |
| the wnt receptor frizzled-4 modulates adam13 metalloprotease activity. | cranial neural crest (cnc) cells are a transient population of stem cells that originate at the border of the neural plate and the epidermis, and migrate ventrally to contribute to most of the facial structures including bones, cartilage, muscles and ganglia. adam13 is a cell surface metalloprotease that is essential for cnc cell migration. here, we show in xenopus laevis embryos that the wnt receptor fz4 binds to the cysteine-rich domain of adam13 and negatively regulates its proteolytic activi ... | 2015 | 25616895 |
| normal table of embryonic development in the four-toed salamander, hemidactylium scutatum. | we present a complete staging table of normal development for the lungless salamander, hemidactylium scutatum (caudata: plethodontidae). terrestrial egg clutches from naturally ovipositing females were collected and maintained at 15 °c in the laboratory. observations, photographs, and time-lapse movies of embryos were taken throughout the 45-day embryonic period. the complete normal table of development for h. scutatum is divided into 28 stages and extends previous analyses of h. scutatum embryo ... | 2015 | 25617760 |
| small-molecule high-throughput screening utilizing xenopus egg extract. | screens for small-molecule modulators of biological pathways typically utilize cultured cell lines, purified proteins, or, recently, model organisms (e.g., zebrafish, drosophila, c. elegans). herein, we describe a method for using xenopus laevis egg extract, a biologically active and highly tractable cell-free system that recapitulates a legion of complex chemical reactions found in intact cells. specifically, we focus on the use of a luciferase-based fusion system to identify small-molecule mod ... | 2015 | 25618336 |
| the frog inner ear: picture perfect? | many recent accounts of the frog peripheral auditory system have reproduced wever's (1973) schematic cross-section of the ear of a leopard frog. we sought to investigate to what extent this diagram is an accurate and representative depiction of the anuran inner ear, using three-dimensional reconstructions made from serial sections of rana pipiens, eleutherodactylus limbatus and xenopus laevis. in rana, three discrete contact membranes were found to separate the posterior otic (=endolymphatic) la ... | 2015 | 25630769 |
| hydrogen sulfide decreases β-adrenergic agonist-stimulated lung liquid clearance by inhibiting enac-mediated transepithelial sodium absorption. | in pulmonary epithelia, β-adrenergic agonists regulate the membrane abundance of the epithelial sodium channel (enac) and, thereby, control the rate of transepithelial electrolyte absorption. this is a crucial regulatory mechanism for lung liquid clearance at birth and thereafter. this study investigated the influence of the gaseous signaling molecule hydrogen sulfide (h2s) on β-adrenergic agonist-regulated pulmonary sodium and liquid absorption. application of the h2s-liberating molecule na2s ( ... | 2015 | 25632025 |
| α- and β-subunit composition of voltage-gated sodium channels investigated with μ-conotoxins and the recently discovered μo§-conotoxin gviij. | we investigated the identities of the isoforms of the α (nav1)- and β (navβ)-subunits of voltage-gated sodium channels, including those responsible for action potentials in rodent sciatic nerves. to examine α-subunits, we used seven μ-conotoxins, which target site 1 of the channel. with the use of exogenously expressed channels, we show that two of the μ-conotoxins, μ-buiiib and μ-sxiiia, are 50-fold more potent in blocking nav1.6 from mouse than that from rat. furthermore, we observed that μ-bu ... | 2015 | 25632083 |
| acute toxic effects of the herbicide formulation and the active ingredient used in cycloxydim-tolerant maize cultivation on embryos and larvae of the african clawed frog, xenopus laevis. | most genetically engineered herbicide-tolerant crops are still awaiting approval in europe. there is, however, a recent trend for the cultivation of cycloxydim-tolerant maize hybrids for use in maize production. we studied the acute toxic effects of the complementary herbicide focus(®) ultra and its active ingredient cycloxydim on embryos and early-stage larvae of the african clawed frog (xenopus laevis). the results indicate that the herbicide formulation is significantly more toxic than the ac ... | 2015 | 25634323 |
| the effects of simazine, a chlorotriazine herbicide, on the expression of genes in developing male xenopus laevis. | simazine was investigated for gene expression concurrent with simazine-induced phenotype changes during development of male xenopus laevis. x. laevis tadpoles (nieuwkoop-faber stage 46) were exposed to 0.1, 1.2, 11.0 and 100.9 μg/l simazine for 100 days. the results showed that an increased mortality of x. laevis, decreased gonad weight and altered gonadosomatic index of males significantly (p<0.05) when exposed to simazine at 11.0 and 100.9 µg/l. significant degeneration in testicular tissues w ... | 2015 | 25634327 |
| expression of a novel serine/threonine kinase gene, ulk4, in neural progenitors during xenopus laevis forebrain development. | we have analyzed the expression pattern of a novel serine/threonine kinase gene ulk4 during forebrain development in xenopus laevis. to this aim, we firstly cloned a ulk4 cdna fragment from x.laevis and generated a rna probe that was used for its detection by in situ hybridization. throughout development xulk4 expression was detected along the ventricular (vz) and subventricular zones (svz) of all forebrain regions, with the exception of the vz of the striatum. in the adult, xulk4 was also mainl ... | 2015 | 25637795 |
| dissecting microtubule structures by laser ablation. | here, we describe a detailed protocol, based on laser ablation and fluorescence optical microscopy, to measure the microtubule organization in spindles, including microtubule length distribution, polarity, and plus and minus end densities. the method uses the asymmetry in microtubule depolymerization after a cut, where the newly created microtubule plus ends depolymerize all the way to the minus ends, whereas the newly created minus ends remain stable. the protocol described in this chapter is o ... | 2015 | 25640424 |
| lizip3 is a cellular zinc transporter that mediates the tightly regulated import of zinc in leishmania infantum parasites. | cellular zinc homeostasis ensures that the intracellular concentration of this element is kept within limits that enable its participation in critical physiological processes without exerting toxic effects. we report here the identification and characterization of the first mediator of zinc homeostasis in leishmania infantum, lizip3, a member of the zip family of divalent metal-ion transporters. the zinc transporter activity of lizip3 was first disclosed by its capacity to rescue the growth of s ... | 2015 | 25644708 |