| nerve-independent dna synthesis and mitosis in regenerating hindlimbs of larval xenopus laevis. | xenopus laevis larvae at stage 52-53 (according to nieuwkoop and faber 1956) were subjected to amputation of both limbs at the thigh level as well as to repeated denervations of the right limb. results obtained in larvae sacrificed during wound healing (1 after amputation), blastema formation (3 days) and blastema growth (5 and 7 days) showed that denervated right limbs have undergone the same histological modifications observed in innervated left limbs and have formed a regeneration blastema co ... | 1992 | 28305578 |
| partial characterization of neural-inducing factors from xenopus gastrulae evidence for a larger protein complex containing the factor. | high (mr ≈ 90-110 kda) and low (mr ≈ 15-30 kda) molecular weight forms of neural-inducing factors have been found in the supernatant of xenopus gastrula homogenate. the factors, which are protein in nature, have been partially purified by size exclusion high-performance liquid chromatography (hplc) and sodium dodecyl sulphate (sds)-polyacrylamide gel electrophoresis. the factor of smaller size, which could be derived from a precursor, is associated with other proteins in a larger complex. the ne ... | 1992 | 28305609 |
| dynamic distribution of region-specific maternal protein during oogenesis and early embryogenesis of xenopus laevis. | for analysing spatial distribution of maternal proteins in an amphibian egg, monoclonal antibodies specific to certain regions were raised. one monoclonal antibody was found (moab xa5b6) which reacted specifically with the animal hemisphere of the mature xenopus laevis egg. the maternal protein that reacted with the moab xa5b6 was shown to be distributed asymmetrically along the dorso-ventral axis in the upper region of the equatorial zone of the fertilized egg. at late blastula stage, the antig ... | 1991 | 28305969 |
| in vitro evidence that interactions betweenxenopus blastomeres restrict cell migration. | the consistency of the frog blastula's fate map is produced, in part, because the progeny of blastomeres located in dfferent regions do not intermix with one another. we examined the cause for this restriction of intermixing in two types of cultures. in one type of culture, two groups of cells were excised from blastulae and stuck together; the movement of cells between the groups was monitored. cells migrated more extensively between groups derived from the same region than between groups deriv ... | 1990 | 28306109 |
| mesodermal induction in early amphibian embryos by activin a (erythroid differentiation factor). | recently the mesoderm-inducing effects of the transforming growth factor β (tgf-β) family of proteins have been widely examined. in an attemt to elucidate the functions of these proteins, porcine inhibin a and activin a (erythroid differentiation factor; edf) were examined. treatment of explants with activin a led to differentiation of mesodermal derivatives such as mesenchyme, notochord, blood cells and muscle, but inhibin a had a much lesser effect. the mesodermal differentiation induced by ac ... | 1990 | 28305412 |
| expression of exogenously introduced bacterial chloramphenicol acetyltransferase genes in xenopus laevis embryos before the midblastula transition. | previous papers have reported that dnas exogenously injected into xenopus laevis fertilized eggs are expressed only at and after the midblastula transition (mbt). we have injected fertilized eggs of xenopus laevis with circular plasmids that contained bacterial chloramphenicol acetyltransferase (cat) genes connected to the promoter of viral genes (psv2cat and pad12.e1acat) or the xenopus cardiac actin gene (actin-cat fusion gene), and examined whether these dnas are expressed during the stage be ... | 1990 | 28305411 |
| epiboly connected with cleavage in morula and early blastula stages of xenopus laevis, a study using time-lapse photography. | measurements were made of the external surface areas occupied by animal and vegetal blastomeres and their daughter cells at successive cleavage cycles in 15 embyros of xenopus laevis. on the animal side, after each cleavage a general area increase (epiboly) occurs from cycle 4 (16-cell stage, stage 5) to cycle 10 (stage 8 1/2), while on the vegetal side there is a slight general area decrease after each cleavage from cycle 6 to cycle 10. the comparison between the external surface areas of indiv ... | 1990 | 28305669 |
| the expression of barley α-amylase genes in xenopus laevis oocytes. | the synthesis and secretion of α-amylase (ec 3.2.1.1) from xenopus laevis oocytes injected with plasmids containing barley α-amylase complementary dna (cdna), genomic dna, or synthetic α-amylase mrna were studied. α-amylase accumulated within the oocytes beginning 12 h after injection of dna and in the medium 12 h later as a result of secretion. s1 mapping showed that the transcription of genomic dna was initiated at the same site in oocytes as in barley aleurone, but that the transcription of c ... | 1990 | 24202011 |
| the metamorphic switch in hemoglobin phenotype ofxenopus laevis involves erythroid cell replacement. | to elucidate the cellular basis of hemoglobin transition inxenopus laevis the distribution of larval and adult hemoglobins was analyzed by indirect immunofluorescence in the circulating erythrocytes during metamorphosis. in addition, the morphological characteristics as well as the capacity for synthesis of dna and hemoglobin in the erythrocytes were followed during the same developmental period. our quantitative analysis on the distribution of larval and adult hemoglobins suggests that they are ... | 1989 | 28305873 |
| developmental pattern and molecular identification of globin chains in xenopus laevis. | high-resolution electrophoresis of larval and adult hemoglobins of xenopus laevis reveals stage-specific differences in the number and mobility of the globin chains. to establish the relationship between the globin chains and the previously described globin genes, the corresponding mrnas were hybrid-selected from total erythroblast rna by representative cdna clones, and translated in vitro. electrophoretic separation of the translation products allowed identification of a major and a minor α-glo ... | 1988 | 28305747 |
| protein kinases in amphibian ectoderm induced for neural differentiation. | ectoderm explants from early gastrula stages of xenopus laevis were induced with a neutralizing factor. the factor was isolated from xenopus gastrulae and partially purified by chromatography on deae cellulose. the ectoderm was cultured for different periods of time and then homogenized. protein kinase activity was determined in the homogenates from induced and control explants with histone h 1 or c-terminal peptide derived from histone h 1 as substrates. the c-terminal peptide is a more specifi ... | 1988 | 28305429 |
| xenopus skin mucus induces oral dyskinesias that promote escape from snakes. | african clawed frogs fed to american water snakes induced yawning and gaping which slowed ingestion and facilitated the frogs' escape without inducing flavor aversion. the peptide and/or indolealkylamine contents of the frog's poison glands caused the effect because frogs with purged glands did not induce these behaviors and rarely escaped. poison gland mucus, applied orally, elicited similar oral movements. the frog's clear lubricating mucus was inactive. as several compounds in the poison glan ... | 1988 | 3227042 |
| crystallins during xenopus laevis free lens formation. | the ontogeny and localization of crystallins during free lens development (i.e. lens development without the optic vesicle) were investigated in xenopus laevis using the indirect immunofluorescence staining method with an antiserum raised against homologous total lens soluble proteins. since the developing free lenses pass through stages similar to those of the lenses regenerated from the inner cell layer of the outer cornea following lentectomy in the same species freeman's classification was u ... | 1988 | 28305564 |
| cell proliferation in ectodermal explants from xenopus embryos. | dissociated prospective ectoderm cells from xenopus laevis embryos divide autonomously up to the 17th division cycle of the embryo. to examine the requirements for the further proliferation of these cells, the continuation of cell division in compact ectodermal explants beyond the 17th division cycle has been studied. such explants develop into aggregates of epidermal cells, as can be shown immunohistochemically with an anti-serum against xenopus epidermal cytokeratin. cell division in these exp ... | 1988 | 28305558 |
| binding of anti-fibronectin to early amphibian ectoderm does not result in inhibition of neural induction under in vitro conditions. | antibodies directed to fibronectin (anti-fn) were injected into the blastocoel of late blastulae of xenopus laevis. two animal caps (ectoderm) were isolated, when control embryos reached the early gastrula stage, and were combined with untreated upper blastopore lip in the sandwich method. in two control series fibronectin or holtfreter solution was injected into the blastocoel. the results of the experiments suggest that neural induction cannot be prevented by binding anti-fn to fibronectin, wh ... | 1987 | 28305695 |
| characterization of repetitive dna transcripts isolated from a xenopus laevis gastrula-stage cdna clone bank. | by screening a cdna library prepared from polyadenylated nuclear rna of xenopus laevis gastrula-stage embryos with total genomic dna we have identified nine clones belonging to seven different families of repeated dna. two of these families exhibit partial sequence homologies and thus probably represent subfamilies of a common origin. the individual families comprise between 0.024% and 1.5% and, in total, about 2% of the x. laevis genome. six of the clones elements represent dispersed repetitive ... | 1987 | 28305657 |
| the direction of cleavage waves and the regional variation in the duration of cleavage cycles on the dorsal side of the xenopus laevis blastula. | the animal and the dorsal side of five embryos of xenopus laevis were studied in detail from the 7th to the 13th cleavage by means of time-lapse cinematography. at each cleavage the regionally ordered sequence of blastomere divisions is visible in the films as a "cleavage wave", propagating about three times slower in the dorsal than in the animal view. in the dorsal view the waves run in an animal-vegetal direction, initially with a left-to-right deviation and in later cleavages converging on t ... | 1986 | 28305687 |
| the inducing capacity of the presumptive endoderm of xenopus laevis studied by transfilter experiments. | the inducing capacity of the vegetal hemisphere of early amphibian blastulae was studied by placing a nucleopore filter (pore size 0.4 μm) between isolated presumptive endoderm and animal (ectodermal) caps. the inducing effect was shown to traverse the nucleopore membrane. the reacting ectoderm differentiated into mainly ventral mesodermal derivatives. expiants consisting of five animal caps also formed dorsal mesodermal and neural structures. those results together with data published elsewhere ... | 1986 | 28305409 |
| neural-inducing activity of nuclei and nuclear fractions from xenopus laevis embryos. | from embryos (xenopus laevis) of different developmental stages nuclei were isolated which exert neural inducing activity in the biological test. the active material could partly be extracted from the nuclei. experiments for the isolation of nuclear ribonucleoprotein (rnp) particles have shown that the activity is localized at least in part in these particles. on the other hand, some neural inducer is not detached from chromatin and the nuclear matrix even with ionic detergents. inducing activit ... | 1986 | 28305447 |
| isolation of plasma membranes from xenopus embryos. | plasma membranes were isolated in high yield from xenopus gastrulae by repeated sedimentation in discontinuous sucrose gradients. most of the yolk was separated by lowspeed sedimentation before centrifugation on the discontinuous sucrose gradients. the isolation of plasma membranes was followed by covalent labelling of the surface of dissociated gastrula cells with diazoniobenzene sulphonate, by electron microscopy and the distribution of enzymatic markers. the isolated plasma membranes have a l ... | 1986 | 28305446 |
| two recessive mutations with maternal effect upon colour and cleavage ofxenopus l. laevis eggs. | "pale eggs" and "partial cleavage" are two mutations with a maternal effect that are found in the same family ofxenopus l. laevis. the pale eggs have animal hemispheres of a yellow to beige colour and give rise to normally pigmented tadpoles and frogs. the cells of pale embryos contain fewer melanosomes than those of controls. the partial cleavage eggs are characterized by an abnormality of cleavage visible from the eight-cell stage onwards, by abnormal yolk platelet distribution and abnormal cy ... | 1984 | 28305590 |
| inducing activity of subcellular fractions from amphibian embryos. | the homogenate from unfertilized eggs, gastrulae, neurulae and hatched embryos ofxenopus laevis was fractionated by differential centrifugation and subsequent repeated centrifugation on discontinuous sucrose gradients. a high archencephalic-neural inducing activity was found in rnp particles, which were released from the high-speed ("microsomal") sediment by treatment with edta, and in a fraction of heterogeneous small vesicles. the highest archencephalic inducing activity was observed in rnp pa ... | 1984 | 28305490 |
| change in the differentiation pattern ofxenopus laevis ectoderm by variation of the incubation time and concentration of vegetalizing factor. | early amphibian gastrula ectoderm (xenopus laevis) has been treated with vegetalizing factor using the sandwich technique, varying the period of incubation and the inducer concentration.the pattern of induced tissues depends on three factors: the inducer concentration, the size of inducer pellet and the time of exposure of ectodermal target cells to inducer.short treatment with inducer will result in the formation of blood cells and heart structures. an increase in incubation time or inducer con ... | 1983 | 28305118 |
| repetitive sequences associated with polyadenylated rna of xenopus laevis embryos. | electron microscopy revealed that transcripts of complementary repetitive sequence elements are widely distributed among long poly (a) containing rna molecules of xenopus laevis. cdna/rna hybridization experiments suggest that many of these polyadenylated transcripts carry protein coding sequences which are interrupted by repetitive elements. our in-vitro translation experiments indicate that removal of repetitive elements must precede the utilization of protein coding sequences associated with ... | 1982 | 28305260 |
| the fate of oocyte nuclear proteins during early development ofxenopus laevis. | the localization and movements of four nuclear proteins, originally contained in the germinal vesicle ofxenopus oocytes, were followed through early development from cleavage to late neurula. the study made use of monoclonal antibodies directed against germinal vesicle proteins. biochemical methods showed that all proteins persist in the embryo without a change in molecular size or gross concentration. at early stages the proteins are localized preferentially in the cytoplasm of the animal hemis ... | 1982 | 28305052 |
| the presence of an endogenous lectin in early embryos ofxenopus laevis. | xenopus laevis embryos were examined for the presence of endogenous carbohydrate binding proteins. soluble extracts of cleavage, gastrula and neurula embryos are able to agglutinate trypsinized rabbit erythrocytes. unlike other embryonic lectins this agglutination activity requires the presence of calcium ions but not of sulphydryl reducing agents. it is specifically inhibited by galactose and galactose containing derivatives. thiodigalactoside is the most potent disaccharide inhibitor followed ... | 1982 | 28305386 |
| cloning of cdna sequences derived from poly(a)+ nuclear rna ofxenopus laevis at different developmental stages: evidence for stage specific regulation. | nuclear poly(a)+ rna was isolated from gastrula and early tadpole stages ofxenopus laevis, transcribed into cdna and integrated as double stranded cdna by the g-c joining method into the pst cleavage site of plasmid pbr 322. after cloning ine. coli strain hb 101 the clone libraries were hybridized to32p labelled cdna derived from nuclear poly(a)+ rna of the two different developmental stages. about 20% of the clones gave a positive hybridization signal thus representing rna molecules of high and ... | 1981 | 28305358 |
| the lens proteins in adult and embryos of the periodic albino mutant ofxenopus laevis. | the crystallins of normal and ap mutants ofx. laevis have been studied using biochemical (electrophoresis in agar and polyacrylamide gels, isoelectric focusing) and immunochemical methods (immunoelectrophoresis, immunodiffusion, immunoabsorption, immunofluorescence, isoelectrofocusing with immunoidentification). the immunochemical analysis was carried out with rabbit antisera prepared against electrophoretic fractions of the mutant lens.crystallins of adultx. laevis (ap/ap; ++/++) are heterogeno ... | 1980 | 28305170 |
| the effects of tunicamycin and 2-deoxy-d-glucose on the development ofxenopus laevis embryos. | tunicamycin and 2-deoxy-d-glucose were applied toxenopus laevis embryos in the first cleavage furrow, blastula and early gastrula stages. no effect was observed with 2-deoxy-d-glucose up to the concentration 0.1 m. the effect of tunicamycin is dose- and stage-dependent. at the concentration of 5 μg/ml cleaving embryos are arrested at the onset of gastrulation and their cells exhibit decreased intercellular adhesivity, while embryos treated in the blastula and early gastrula stages may develop up ... | 1980 | 28305930 |
| the role of tensile fields and contact cell polarization in the morphogenesis of amphibian axial rudiments. | the role of stretching-generated tensile stresses upon the organization of axial rudiments have been studied. pieces of the dorsal wall ofxenopus laevis andrana temporaria embryos at the late gastrula stage were rotated through 90°, transplanted into the field of neurulation tensions of another embryo and replaced by ventral tissues already insensitive to inductive influences. the axial rudiments which developed from rotated and transplanted dorsal tissues oped from rotated and transplanted dors ... | 1980 | 28305148 |
| quantitative aspects of rna synthesis in normal and lithium-treated embryos ofxenopus laevis. | the treatment ofxenopus early embryos with lithium chloride produces exogastruale - embryos which fail to gastrulate normally and in which the rates of cell division are reduced. in the present study estimations of incorporations of (5-3h) uridine and the specific activities of the 5'-ribonucleotide precursor pools showed that exogastrulae have higher rates of rna synthesis per cell than control neurulae. sub-cellular fractionations showed that a greater proportion of labelled rna was retained i ... | 1979 | 28305001 |
| changes in the cell surface coat during the development ofxenopus laevis embryos, detected by lectins. | the composition of the surface coat in embryonic cells ofxenopus laevis was examined by agglutination and fluorescent staining with lectins.cells of early and mid gastrula stages were agglutinated by lectins specific for d-mannose, d-galactose, l-fucose, n-acetyl-d-glucosamine and n-acetyl-d-galactosamine. no differences in agglutinability among ectoderm, mesoderm and endoderm cells were observed with lectins specific for d-mannose, d-galactose and n-acetyl-d-galactosamine, though agglutination ... | 1978 | 28305035 |
| melanin synthesis activation dependent on inductive influences. | gene activity in melanin-synthesising cells of albino periodic (ap) mutants ofxenopus laevis is expressed phenotypically in the framework of the following cycle: a period of complete albinism succeeds the short peak of pigmentation, and melanosomes which have formed disappear. skin and choroid coat melanophores as well as pigmented epithelium melanocytes are involved in this cycle.parabiosis experiments allowed hormonal regulation of the melanin-synthesising gene activity to be excluded. neural ... | 1978 | 28305010 |
| differentiated protein synthesis with polysomes from petunia ovaries before fertilization. | polysomes from cross-, self- and unpollinated ovaries have been injected in xenopus laevis eggcells. the synthesised proteins have been identified by means of gel-electrophoresis. it appeared that few hours after pollination the protein pattern of the pollinated ovary has changed in comparison with that of unpollinated ones. however, in this early stage, there is only little difference found in the protein pattern of selfed and crossed ovaries. from 12 h after pollination and onwards, the differ ... | 1977 | 24425225 |
| inducing activity of fractionated microsomal material from thexenopus laevis gastrula stage. | the postmitochondrial supernatant fromxenopus gastrulae has been fractionated on sucrose gradients. part of the microsomal material was treated with edta, which dissociates most of the polysomal and monosomal material into ribosomal subunits. in addition, a series of pooled fractions from the edta treated gradients has been applied to discontinuous gradients in more concentrated sucrose to separate membranous material from the remaining microsomal components.pooled fractions from all gradients h ... | 1976 | 28305523 |
| [a comparison of the inducing ability from the superficial layer of the yolk platelet coats and the microsomal fraction of cleavage, gastrula and neurula stages of xenopus laevis]. | deuterencephalic and spinocaudal inducing activity is extractable from the yolk platelet coats and the microsomal fraction of cleavage, gastrula and neurula stages ofxenopus laevis.extracts of both cell fractions from the gastrula and neurula cause a significantly stronger deuterencephalic and spinocaudal reaction than those from cleavage stages, when tested antriturus alpestus ectoderm. | 1974 | 28304839 |
| [not available]. | | 1948 | 18891702 |
| divergent axial morphogenesis and earlyshhexpression in vertebrate prospective floor plate. | the notochord has organizer properties and is required for floor plate induction and dorsoventral patterning of the neural tube. this activity has been attributed to sonic hedgehog (shh) signaling, which originates in the notochord, forms a gradient, and autoinducesshhexpression in the floor plate. however, reported data are inconsistent and the spatiotemporal development of the relevantshhexpression domains has not been studied in detail. we therefore studied the expression dynamics ofshhin rab ... | 2018 | 29423139 |
| cloning and spatiotemporal expression of xenopus laevis apolipoprotein ci. | apolipoprotein ci (apoci) belongs to the apolipoprotein superfamily, members of which are involved in lipid transport, uptake and homeostasis. excessive apoci has been implicated in atherosclerosis and alzheimer's disease in humans. in this study we report the isolation of xenopus laevis apoci and describe the expression pattern of this gene during early development, using reverse transcription polymerase chain reaction and whole mount in situ hybridization. xenopus apoci is enriched in the dors ... | 2018 | 29346450 |
| monepantel is a non-competitive antagonist of nicotinic acetylcholine receptors from ascaris suum and oesophagostomum dentatum. | zolvix®is a recently introduced anthelmintic drench containing monepantel as the active ingredient. monepantel is a positive allosteric modulator of deg-3/des-2 type nicotinic acetylcholine receptors (nachrs) in several nematode species. the drug has been reported to produce hypercontraction of caenorhabditis elegans and haemonchus contortus somatic muscle. we investigated the effects of monepantel on nachrs from ascaris suum and oesophagostomum dentatum heterologously expressed in xenopus laevi ... | 2017 | 29366967 |
| 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 |
| 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 |
| characterization of pax3 and sox10 transgenic xenopus laevis embryos as tools to study neural crest development. | the neural crest is a multipotent population of cells that originates a variety of cell types. many animal models are used to study neural crest induction, migration and differentiation, with amphibians and birds being the most widely used systems. a major technological advance to study neural crest development in mouse, chick and zebrafish has been the generation of transgenic animals in which neural crest specific enhancers/promoters drive the expression of either fluorescent proteins for use ... | 2018 | 29522707 |
| molecular and functional characterization of the gulf toadfish serotonin transporter (sert; slc6a4). | the serotonin transporter (sert) functions in the uptake of the neurotransmitter serotonin (5-ht) from the extracellular milieu and is the molecular target of the selective serotonin reuptake inhibitors (ssris), a common group of antidepressants. the current study comprehensively assesses the sequence, tissue distribution, transport kinetics, and physiological function of a teleost sert. the 2,022-bp toadfish sert sequence encodes a protein of 673 amino acids, which shows 83% similarity to zebra ... | 2018 | 29487159 |
| fam60al as a novel factor involved in reprogramming of somatic cell nuclear transfer in zebrafish (danio rerio). | the main reason for abnormal development of cloned animals or embryos, and inefficient animal cloning, is a poor understanding of the reprogramming mechanism. to better comprehend reprogramming and subsequent generation of pluripotent stem cells, we must investigate factors related to reprogramming of somatic cells as nuclear donors. as we know,fam60al(family with sequence similarity 60, member a, like) is a coding gene only found in zebrafish and frog (xenopus laevis) among vertebrates. however ... | 2018 | 29483827 |
| chemical screening using cell-freexenopusegg extract. | most drug screening methods use purified proteins, cultured cells, and/or small model organisms such asxenopus, zebrafish, flies, or nematodes. these systems have proven successes in drug discovery, but they also have weaknesses. although purified cellular components allow for identification of compounds with activity against specific targets, such systems lack the complex biological interactions present in cellular and organismal screens. in vivo systems overcome these weaknesses, but the lack ... | 2018 | 29475996 |
| expression of the adhesion g protein-coupled receptor a2 (adgra2) during xenopus laevis development. | the adhesion g protein-coupled receptor a2 (adgra2) is a seven transmembrane receptor that has been described to be a regulator for angiogenesis in mice. furthermore, the zebrafish ouchless mutant is unable to develop dorsal root ganglia through a disrupted trafficking of adgra2. besides rna sequencing data, nothing is reported about adgra2 in the south african crawled frog xenopus laevis. in this study, we investigated for the first time the spatio-temporal expression of adgra2 during early xen ... | 2018 | 29462671 |
| expression patterns of zebrafishnocturningenes and the transcriptional activity of the frognocturninpromoter in zebrafish rod photoreceptors. | daily modulation of gene expression is critical for the circadian rhythms of many organisms. one of the modulating mechanisms is based on nocturnin, a deadenylase that degrades mrna in a circadian fashion. thenocturningenes are expressed broadly, but their tissue expression patterns differ between mice and the frogxenopus laevis; this difference suggests that the extent of the regulation ofnocturingene expression varies among species. in this study, we set out to characterize the expression patt ... | 2017 | 29386877 |
| heterologous expression of aedes aegypti cation chloride cotransporter 2 (aeccc2) in xenopus laevis oocytes induces an enigmatic na⁺/li⁺ conductance. | the yellow fever mosquito aedes aegypti possesses three genes encoding putative na⁺-coupled cation chloride cotransporters (cccs): aenkcc1, aeccc2, and aeccc3. to date, none of the aecccs have been functionally characterized. here we expressed aeccc2 heterologously in xenopus oocytes and measured the uptake of li⁺ (a tracer for na⁺) and rb⁺ (a tracer for k⁺). compared to control (h₂o-injected) oocytes, the aeccc2-expressing oocytes exhibited significantly greater uptake of li⁺, but not rb⁺. howe ... | 2019 | 30875796 |
| the effects of insecticides on two splice variants of the glutamate-gated chloride channel receptor of the major malaria vector, anopheles gambiae. | between half to 1 million people die annually from malaria. anopheles gambiae mosquitoes are major malaria vectors. unfortunately, resistance has emerged to the agents currently used to control a. gambiae, creating a demand for novel control measures. the pentameric glutamate-gated chloride channel (glucl) expressed in the muscle and nerve cells of these organisms are a potentially important biological target for malaria control. the pharmacological properties of anophiline glucl receptors are, ... | 2019 | 31479507 |
| periodic albinism of a widely used albino mutant of xenopus laevis caused by deletion of two exons in the hermansky-pudlak syndrome type 4 gene. | the periodic albino mutant of xenopus laevis is a recessive mutant, in which reduced amounts of melanin appear in the retinal pigment epithelium (rpe) and in melanophores at the late embryonic stage, after which both rpe and melanophores gradually depigment. three types of pigment cells (melanophores, iridophores, and xanthophores) have been reported to be affected in this albino. however, the causative gene of the periodic albinism remains unknown. hermansky-pudlak syndrome (hps) is an autosoma ... | 2020 | 33147376 |
| disease-associated hcn4 v759i variant is not sufficient to impair cardiac pacemaking. | the hyperpolarization-activated cation current if is a key determinant for cardiac pacemaker activity. it is conducted by subunits of the hyperpolarization-activated cyclic nucleotide-gated (hcn) channel family, of which hcn4 is predominant in mammalian heart. both loss-of-function and gain-of-function mutations of the hcn4 gene are associated with sinus node dysfunction in humans; however, their functional impact is not fully understood yet. here, we sought to characterize a hcn4 v759i variant ... | 2020 | 33095298 |
| using an aquatic model, xenopus laevis, to uncover the role of chromodomain 1 in craniofacial disorders. | the chromodomain family member chromodomain 1 (chd1) has been shown to have numerous critical molecular functions including transcriptional regulation, splicing, and dna repair. complete loss of function of this gene is not compatible with life. on the other hand, missense and copy number variants of chd1 can result in intellectual disabilities and craniofacial malformations in human patients including cleft palate and pilarowski-bjornsson syndrome. we have used the aquatic developmental model o ... | 2020 | 32918369 |
| acute consequences of a unilateral viiith nerve transection on vestibulo-ocular and optokinetic reflexes in xenopus laevis tadpoles. | loss of peripheral vestibular function provokes severe impairments of gaze and posture stabilization in humans and animals. however, relatively little is known about the extent of the instantaneous deficits. this is mostly due to the fact that in humans a spontaneous loss often goes unnoticed initially and targeted lesions in animals are performed under deep anesthesia, which prevents immediate evaluation of behavioral deficits. here, we use isolated preparations of xenopus laevis tadpoles with ... | 2020 | 32915311 |
| l-glutamic acid monosodium salt reduces the harmful effect of lithium on the development of xenopus laevis embryos. | many xenobiotics in the environment affect the human body in various ways. among those xenobiotics, lithium chloride (li, licl) and monosodium glutamate (l-glutamic acid monosodium salt, msg) compounds affect the crucial processes of stem cell differentiation, cell proliferation, developmental gene expression, and overall development in animals. in this study, we aimed to examine the developmental effects of exposure to flavor enhancer msg and lici medicament on xenopus embryos using the frog em ... | 2020 | 32705564 |
| uncoupling sodium channel dimers restores the phenotype of a pain-linked nav 1.7 channel mutation. | the voltage-gated sodium channel nav 1.7 is essential for adequate perception of painful stimuli. mutations in the encoding gene, scn9a, cause various pain syndromes in humans. the hnav 1.7/a1632e channel mutant causes symptoms of erythromelalgia and paroxysmal extreme pain disorder (pepd), and its main gating change is a strongly enhanced persistent current. on the basis of recently published 3d structures of voltage-gated sodium channels, we investigated how the inactivation particle binds to ... | 2020 | 32663327 |
| trpm6 and trpm7: novel players in cell intercalation during vertebrate embryonic development. | a common theme in organogenesis is how the final structure of organs emerge from epithelial tube structures, with the formation of the neural tube being one of the best examples. two types of cell movements co-occur during neural tube closure involving the migration of cells toward the midline of the embryo (mediolateral intercalation or convergent extension) as well as the deep movement of cells from inside the embryo to the outside of the lateral side of the neural plate (radial intercalation) ... | 2020 | 32315468 |
| effects of bisphenol a and its alternative bisphenol f on notch signaling and intestinal development: a novel signaling by which bisphenols disrupt vertebrate development. | we previously found bisphenol a (bpa) alternative, bisphenol f (bpf) upregulated notch-related gene expression in intestines of the african clawed frog xenopus laevis, suggesting an agonistic action on notch signaling, a crucial signaling in multiple biological processes during development. here, we aimed to confirm the actions of bpa and bpf on notch signaling and to reveal their effects on intestinal development. using x. laevis, an excellent model for developmental biology, we found that 10-1 ... | 2020 | 32311622 |
| modeling bainbridge-ropers syndrome in xenopus laevis embryos. | the additional sex combs-like (asxl1-3) genes are linked to human neurodevelopmental disorders. the de novo truncating variants in asxl1-3 proteins serve as the genetic basis for severe neurodevelopmental diseases such as bohring-opitz, shashi-pena, and bainbridge-ropers syndromes, respectively. the phenotypes of these syndromes are similar but not identical, and include dramatic craniofacial defects, microcephaly, developmental delay, and severe intellectual disability, with a loss of speech an ... | 2020 | 32132929 |
| hplc reveals novel features of nucleoside and nucleobase homeostasis, nucleoside metabolism and nucleoside transport. | humans possess three members of the cation-coupled concentrative nucleoside transporter cnt (slc 28) family, hcnt1-3: hcnt1 is selective for pyrimidine nucleosides but also transports adenosine, hcnt2 transports purine nucleosides and uridine, and hcnt3 transports both pyrimidine and purine nucleosides. hcnt1/2 transport nucleosides using the transmembrane na+ electrochemical gradient, while hcnt3 is both na+- and h+-coupled. by producing recombinant hcnt3 in xenopus laevis oocytes, we have used ... | 2020 | 32126230 |
| evaluation of the effects of low concentrations of bisphenol af on gonadal development using the xenopus laevis model: a finding of testicular differentiation inhibition coupled with feminization. | developmental exposures to estrogenic chemicals possibly cause structural and functional abnormalities of reproductive organs in vertebrates. bisphenol af (bpaf), a bisphenol a (bpa) analogue, has been shown to have higher estrogenic activity than bpa, but little is known about the effects of bpaf on gonadal development, particularly gonadal differentiation. we aimed to determine whether low concentrations of bpaf could disrupt gonadal differentiation and subsequent development using xenopus lae ... | 2020 | 31991354 |
| cfap43 modulates ciliary beating in mouse and xenopus. | malfunctions of motile cilia cause a variety of developmental defects and diseases in humans and animal model organisms. defects include impaired mucociliary clearance of the airways, sperm immotility, hydrocephalus and organ laterality. here, we characterize the evolutionary conserved cfap43 gene by loss-of-function experiments in the mouse and the frog xenopus laevis. cfap43 is expressed in tissues carrying motile cilia and acts as a target gene of the transcription factor foxj1, which is esse ... | 2020 | 31884020 |
| insights regarding skin regeneration in non-amniote vertebrates: skin regeneration without scar formation and potential step-up to a higher level of regeneration. | skin wounds are among the most common injuries in animals and humans. vertebrate skin is composed of an epidermis and dermis. after a deep skin injury in mammals, the wound heals, but the dermis cannot regenerate. instead, collagenous scar tissue forms to fill the gap in the dermis, but the scar does not function like the dermis and often causes disfiguration. in contrast, in non-amniote vertebrates, including fish and amphibians, the dermis and skin derivatives are regenerated after a deep skin ... | 2020 | 31831357 |
| impact of copper in xenopus laevis liver: histological damages and atp7b downregulation. | copper is an essential micronutrient but its excess in the dietary can be toxic. both copper deficiency and abundance can occur in natural conditions and can lead to pathological dysfunctions. many of the toxic effects of copper, such as increased lipid peroxidation in cell membranes and dna damage, are due to its role in the generation of oxygen free radicals. copper is released into the environment by both natural sources and human activities and it can damage organisms and ecosystems. in the ... | 2020 | 31757510 |
| [exploring the mysteries of megakaryocytopoiesis and thrombopoiesis through comparative hematology]. | in modern hematology, research on hematopoiesis and blood cells in vertebrates, such as birds, reptiles, amphibians, and fish, is lagging. this is because there are many experimental constraints when selecting subjects other than humans and mice as research subjects. currently, the availability of flow cytometry to count classified nucleated blood cells and utilization of whole genome information have led to novel findings. for example, in case of amphibian hematopoiesis studies, megakaryocytes ... | 2019 | 31597828 |
| distinct host-mycobacterial pathogen interactions between resistant adult and tolerant tadpole life stages of xenopus laevis. | mycobacterium marinum is a promiscuous pathogen infecting many vertebrates, including humans, whose persistent infections are problematic for aquaculture and public health. among unsettled aspects of host-pathogen interactions, the respective roles of conventional and innate-like t (it) cells in host defenses against m. marinum remain unclear. in this study, we developed an infection model system in the amphibian xenopus laevis to study host responses to m. marinum at two distinct life stages, t ... | 2019 | 31591148 |
| different pharmacological properties of glut9a and glut9b: potential implications in preeclampsia. | glucose transporter 9 (glut9/slc2a9) is the major regulator of uric acid homeostasis in humans. hyperuricemia due to impaired regulation by glut9 in pregnancy is closely associated with preeclampsia. while glut9 is expressed in two alternative splice variants, glut9a and glut9b, with different subcellular localizations, no functional differences of the two splice variants are known to date. the aim of this study was to investigate the function of both glut9 isoforms. | 2019 | 31502429 |
| heterologous hyaluronic acid production in kluyveromyces lactis. | hyaluronic acid (ha) is a biopolymer composed by the monomers glucuronic acid (glcua) and n-acetyl glucosamine (glcnac). it has a broad range of applications in the field of medicine, being marketed between usd 1000-5000/kg. its primary sources include extraction of animal tissue and fermentation using pathogenic bacteria. however, in both cases, extensive purification protocols are required to prevent toxin contamination. in this study, aiming at creating a safe ha producing microorganism, the ... | 2019 | 31466214 |
| advancing genetic and genomic technologies deepen the pool for discovery in xenopus tropicalis. | xenopus laevis and xenopus tropicalis have long been used to drive discovery in developmental, cell, and molecular biology. these dual frog species boast experimental strengths for embryology including large egg sizes that develop externally, well-defined fate maps, and cell-intrinsic sources of nutrients that allow explanted tissues to grow in culture. development of the xenopus cell extract system has been used to study cell cycle and dna replication. xenopus tadpole tail and limb regeneration ... | 2019 | 31254427 |
| adaptive correction of craniofacial defects in pre-metamorphic xenopus laevis tadpoles involves thyroid hormone-independent tissue remodeling. | although it is well established that some organisms can regenerate lost structures, the ability to remodel existing malformed structures has been less well studied. therefore, in this study we examined the ability of pre-metamorphic xenopus laevis tadpoles to self-correct malformed craniofacial tissues. we found that tadpoles can adaptively improve and normalize abnormal craniofacial morphology caused by numerous developmental perturbations. we then investigated the tissue-level and molecular me ... | 2019 | 31253636 |
| the amphibian (xenopus laevis) colony-stimulating factor-1 and interleukin-34-derived macrophages possess disparate pathogen recognition capacities. | pathogens such as the frog virus 3 (fv3) ranavirus are contributing to the worldwide amphibian declines. while amphibian macrophages (mϕs) are central to the immune defenses against these viruses, the pathogen recognition capacities of disparate amphibian mϕ subsets remain unexplored. in turn, mϕ differentiation and functionality are interdependent on the colony-stimulating factor-1 receptor (csf-1r), which is ligated by colony-stimulating factor-1 (csf-1) and the unrelated interleukin-34 (il-34 ... | 2019 | 31029710 |
| the voltage sensing phosphatase (vsp) localizes to the apical membrane of kidney tubule epithelial cells. | voltage-sensing phosphatases (vsps) are transmembrane proteins that couple changes in membrane potential to hydrolysis of inositol signaling lipids. vsps catalyze the dephosphorylation of phosphatidylinositol phosphates (pips) that regulate diverse aspects of cell membrane physiology including cell division, growth and migration. vsps are highly conserved among chordates, and their rna transcripts have been detected in the adult and embryonic stages of frogs, fish, chickens, mice and humans. how ... | 2019 | 30964862 |
| developmental exposure to chemicals associated with unconventional oil and gas extraction alters immune homeostasis and viral immunity of the amphibian xenopus. | although aquatic vertebrates and humans are increasingly exposed to water pollutants associated with unconventional oil and gas extraction (uog), the long-term effects of these pollutants on immunity remains unclear. we have established the amphibian xenopus laevis and the ranavirus frog virus 3 (fv3) as a reliable and sensitive model for evaluating the effects of waterborne pollutants. x. laevis tadpoles were exposed to a mixture of equimass amount of uog chemicals with endocrine disrupting act ... | 2019 | 30939317 |
| developmental regulation of wnt signaling by nagk and the udp-glcnac salvage pathway. | in a screen for human kinases that regulate xenopus laevis embryogenesis, we identified nagk and other components of the udp-glcnac glycosylation salvage pathway as regulators of anteroposterior patterning and wnt signaling. we find that the salvage pathway does not affect other major embryonic signaling pathways (fgf, tgfβ, notch, or shh), thereby demonstrating specificity for wnt signaling. we show that the role of the salvage pathway in wnt signaling is evolutionarily conserved in zebrafish a ... | 2019 | 30904594 |
| stage-dependent cardiac regeneration in xenopus is regulated by thyroid hormone availability. | despite therapeutic advances, heart failure is the major cause of morbidity and mortality worldwide, but why cardiac regenerative capacity is lost in adult humans remains an enigma. cardiac regenerative capacity widely varies across vertebrates. zebrafish and newt hearts regenerate throughout life. in mice, this ability is lost in the first postnatal week, a period physiologically similar to thyroid hormone (th)-regulated metamorphosis in anuran amphibians. we thus assessed heart regeneration in ... | 2019 | 30755533 |
| ketone body modulation of ligand-gated ion channels. | ketogenesis is a metabolic process wherein ketone bodies are produced from the breakdown of fatty acids. in humans, fatty acid catabolism results in the production of acetyl-coa which can then be used to synthesize three ketone bodies: acetoacetate, acetone, and β-hydroxybutyrate. ketogenesis occurs at a higher rate in situations of low blood glucose, such as during fasting, heavy alcohol consumption, and in situations of low insulin, as well as in individuals who follow a 'ketogenic diet' consi ... | 2019 | 30562540 |
| physiological effects of kdm5c on neural crest migration and eye formation during vertebrate development. | lysine-specific histone demethylase 5c (kdm5c) belongs to the jumonji family of demethylases and is specific for the di- and tri-demethylation of lysine 4 residues on histone 3 (h3k4 me2/3). kdm5c is expressed in the brain and skeletal muscles of humans and is associated with various biologically significant processes. kdm5c is known to be associated with x-linked mental retardation and is also involved in the development of cancer. however, the developmental significance of kdm5c has not been e ... | 2018 | 30522514 |
| ivermectin promotes peripheral nerve regeneration during wound healing. | peripheral nerves have the capacity to regenerate due to the presence of neuroprotective glia of the peripheral nervous system, schwann cells. upon peripheral nerve injury, schwann cells create a permissive microenvironment for neuronal regrowth by taking up cytotoxic glutamate and secreting neurotrophic signaling molecules. impaired peripheral nerve repair is often caused by a defective schwann cell response after injury, and there is a critical need to develop new strategies to enhance nerve r ... | 2018 | 30411007 |
| in vitro inhibition of human nucleoside transporters and uptake of azacitidine by an isocitrate dehydrogenase-2 inhibitor enasidenib and its metabolite agi-16903. | 1. the present study investigated inhibitory effects of enasidenib and its metabolite agi-16903 on (a) recombinant human nucleoside transporters (hnts) in hnt-producing xenopus laevis oocytes, and (b) azacitidine uptake in a normal b-lymphoblast peripheral blood cell line (pbc) and acute myeloid leukemia (aml) cell lines. 2. enasidenib inhibited hent1, hent2, hent3, and hent4 in oocytes with ic50 values of 7, 63, 27, and 76 μm, respectively, but exhibited little inhibition of hcnt1-3. agi-16903 ... | 2019 | 30394160 |
| paracetamol-induced liver injury modelled in xenopus laevis embryos. | failure to predict drug-induced liver injury (dili) remains a major contributing factor to lead compound drop-out during drug development. xenopus embryos are amenable for early stage medium throughput small molecule screens and so have the potential to be used in pre-clinical screens. to begin to assess the usefulness and limitations of xenopus embryos for safety assessment in the early phases of drug development, paracetamol was used as a model hepatotoxin. paracetamol overdose is associated w ... | 2019 | 30282005 |
| i spy with my little eye: a simple behavioral assay to test color sensitivity on digital displays. | passive and interactive virtual reality (vr) environments are becoming increasingly popular in the field of behavioral neuroscience. while the technique was originally developed for human observers, corresponding applications have been adopted for the research of visual-driven behavior and neural circuits in animals. rgb color reproduction using red, green and blue primary color pixels is generally calibrated for humans, questioning if the distinct parameters are also readily transferable to oth ... | 2018 | 30127095 |
| 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 |
| 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 |
| 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 |
| conservation and divergence of protein pathways in the vertebrate heart. | heart disease is the leading cause of death in the western world. attaining a mechanistic understanding of human heart development and homeostasis and the molecular basis of associated disease states relies on the use of animal models. here, we present the cardiac proteomes of 4 model vertebrates with dual circulatory systems: the pig (sus scrofa), the mouse (mus musculus), and 2 frogs (xenopus laevis and xenopus tropicalis). determination of which proteins and protein pathways are conserved and ... | 2019 | 31490923 |
| discovery of the arp2 protein as a determining molecule in tumor cell death. | cancer is a multifactorial disease that constitutes a serious public health problem worldwide. prostate cancer advanced stages are associated with the development of androgen-independent tumors and an apoptosis-resistant phenotype that progresses to metastasis. by studying androgen-independent lymphoid nodule carcinoma of the prostate (lncap) cells induced to apoptosis by serum elimination, we identified the activation of a non-selective cationic channel of 23ps conductance that promotes incomin ... | 2019 | 32091029 |
| descubrimiento de la proteína reguladora de apoptosis 2 como determinante en la muerte de células tumorales. | cancer is a multifactorial disease that constitutes a serious public health problem worldwide. prostate cancer advanced stages are associated with the development of androgen-independent tumors and an apoptosis-resistant phenotype that progresses to metastasis. by studying androgen-independent lymphoid nodule carcinoma of the prostate (lncap) cells induced to apoptosis by serum elimination, we identified the activation of a non-selective cationic channel of 23ps conductance that promotes incomin ... | 2019 | 31695224 |
| a flipr assay for discovery of gabaa receptor modulators of natural origin. | a fluorometric imaging plate reader (flipr) assay utilizing chinese hamster ovary (cho) cells stably transfected with gabaa receptors of α1β2γ2 subunit composition was evaluated and validated for rapid screening of plant extract libraries and efficient localization of active compounds in extracts. validation was performed with pure compounds and extracts known to contain allosteric gabaa receptor modulators. plants extracts that had been previously reported as active in an assay using xenopus la ... | 2019 | 31127604 |
| cardiovascular pharmacology of k2p17.1 (task-4, talk-2) two-pore-domain k+ channels. | k2p17.1 (task-4, talk-2) potassium channels are expressed in the heart and represent potential targets for pharmacological management of atrial and ventricular arrhythmias. reduced k2p17.1 expression was found in atria and ventricles of heart failure (hf) patients. modulation of k2p17.1 currents by antiarrhythmic compounds has not been comprehensively studied to date. the objective of this study was to investigate acute effects of clinically relevant antiarrhythmic drugs on human k2p17.1 channel ... | 2018 | 30008082 |
| evaluation of a multiplexed, multispecies nuclear receptor assay for chemical hazard assessment. | sensitivity to potential endocrine disrupting chemicals in the environment varies across species and is influenced by sequence conservation of their nuclear receptor targets. here, we evaluated a multiplexed, in vitro assay testing receptors relevant to endocrine and metabolic disruption from five species. the trans-factorial™ system of human nuclear receptors was modified to include additional species: mouse (mus musculus), frog (xenopus laevis), zebrafish (danio rerio), chicken (gallus gallus) ... | 2020 | 33049310 |
| organelle size scaling over embryonic development. | cell division without growth results in progressive cell size reductions during early embryonic development. how do the sizes of intracellular structures and organelles scale with cell size and what are the functional implications of such scaling relationships? model organisms, in particular caenorhabditis elegans worms, drosophila melanogaster flies, xenopus laevis frogs, and mus musculus mice, have provided insights into developmental size scaling of the nucleus, mitotic spindle, and chromosom ... | 2020 | 32003549 |
| polyunsaturated fatty acid-derived iks channel activators shorten the qt interval ex-vivo and in-vivo. | we aimed to assess the ability of natural and modified polyunsaturated fatty acids (pufas) to shorten qt interval in ex-vivo and in-vivo guinea pig hearts. | 2020 | 32223014 |
| investigation of non-cb1, non-cb2 win55212-2-sensitive g-protein-coupled receptors in the brains of mammals, birds, and amphibians. | previous studies have found non-cb1 non-cb2 g-protein-coupled receptors in rodents that are activated by the aminoalkylindole cannabinoid agonist win55212-2. this work obtained evidence for the presence or absence of similar receptors in the brains of other mammals, birds and amphibians. | 2018 | 30376752 |
| modulation by neonicotinoids of honeybee α1/chicken β2 hybrid nicotinic acetylcholine receptors expressed in xenopus laevis oocytes. | neonicotinoids targeting insect nicotinic acetylcholine (ach) receptors (insect nachrs) are used for crop protection, but there is a concern about adverse effects on pollinators such as honeybees (apis mellifera). thus, we investigated the agonist actions of neonicotinoids (imidacloprid, thiacloprid and clothianidin) on a. mellifera α1 (amα1)/chicken β2 hybrid nachrs in xenopus laevis oocytes according to the subunit stoichiometry of (amα1)3(β2)2 and (amα1)2(β2)3 using voltage-clamp electrophysi ... | 2020 | 32448414 |
| the mechanism of loop c-neonicotinoid interactions at insect nicotinic acetylcholine receptor α1 subunit predicts resistance emergence in pests. | neonicotinoids selectively modulate insect nicotinic acetylcholine receptors (insect nachrs). studies have shown that serine with ability to form a hydrogen bond in loop c of some insect nachr α subunits and glutamate with a negative charge at the corresponding position in vertebrate nachrs may contribute to enhancing and reducing the neonicotinoid actions, respectively. however, there is no clear evidence what loop c properties underpin the target site actions of neonicotinoids. thus, we have i ... | 2020 | 32371996 |
| environmental oxygen exposure allows for the evolution of interdigital cell death in limb patterning. | amphibians form fingers without webbing by differential growth between digital and interdigital regions. amniotes, however, employ interdigital cell death (icd), an additional mechanism that contributes to a greater variation of limb shapes. here, we investigate the role of environmental oxygen in the evolution of icd in tetrapods. while cell death is restricted to the limb margin in amphibians with aquatic tadpoles, eleutherodactylus coqui, a frog with terrestrial-direct-developing eggs, has ce ... | 2019 | 31204171 |
| transcriptome profiling reveals male- and female-specific gene expression pattern and novel gene candidates for the control of sex determination and gonad development in xenopus laevis. | xenopus laevis is an amphibian (frog) species widely used in developmental biology and genetics. to unravel the molecular machinery regulating sex differentiation of xenopus gonads, we analyzed for the first time the transcriptome of developing amphibian gonads covering sex determination period. we applied microarray at four developmental stages: (i) nf50 (undifferentiated gonad during sex determination), (ii) nf53 (the onset of sexual differentiation of the gonads), (iii) nf56 (sexual different ... | 2019 | 30972573 |
| expression of tcr genes in adult and larval xenopus laevis. | in order to better understand the development and function of γδ t cells in xenopus frogs, it is necessary to determine where and when γδ t cells are found in xenopus tissues. this study examined the expression of tcr genes, focused primarily on tcr γ, in tissues of adult and larval xenopus laevis and provide new data about the expression pattern of these different tcr genes in this anuran amphibian. tcr gene expression was detected by rt-pcr in adult frog tissues including the thymus, spleen, s ... | 2019 | 30738793 |
| combined effects of mutations in loop c and the loop d-e-g triangle on neonicotinoid interactions with drosophila dα1/chicken β2 hybrid nachrs. | neonicotinoid insecticides interact with the orthosteric sites of nicotinic acetylcholine receptors (nachrs) formed at the interfaces of (a) two adjacent α subunits and (b) α and non-α subunits. however, little is known of the detailed contributions of these two orthosteric sites to neonicotinoid actions. we therefore applied voltage-clamp electrophysiology to the dα1/chicken β2 hybrid nachr expressed in xenopus laevis oocytes to explore the agonist actions of imidacloprid and thiacloprid on wil ... | 2018 | 30704712 |
| the publications of embryologist lev v. beloussov. | a list of papers and books of the late lev v. beloussov was compiled and is available in word and endnote supplements. the breadth of his work is briefly described. | 2018 | 30321582 |