Publications

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aurora-a: an expedition to the pole of the spindle in xenopus egg extracts.the aim of this short review is to describe the contribution of xenopus laevis egg extracts to the discovery and understanding of the regulation and function of the serine/threonine kinase aurora-a. the power of these extracts to recapitulate cell cycle events makes them a precious tool to decipher complex biological processes at the molecular level, including the mechanisms that affect aurora-a (post-translational modifications) and mechanisms in which aurora-a plays a crucial role (bipolar spi ...201627759154
studying essential dna metabolism proteins in xenopus egg extract.the correct duplication of genetic information is essential to maintain genome stability, which is lost in cancer cells. replication fork integrity is ensured by a number of dna metabolism proteins that assist replication of chromatin regions difficult to replicate due to their intrinsic dna sequence composition, coordinate repair of dna molecules resulting from aberrant replication events or protect replication forks in the presence of lesions impairing their progression. some dna metabolism ge ...201627759152
two light-activated neuroendocrine circuits arising in the eye trigger physiological and morphological pigmentation.two biological processes regulate light-induced skin colour change. a fast 'physiological pigmentation change' (i.e. circadian variations or camouflage) involves alterations in the distribution of pigment containing granules in the cytoplasm of chromatophores, while a slower 'morphological pigmentation change' (i.e. seasonal variations) entails changes in the number of pigment cells or pigment type. although linked processes, the neuroendocrine coordination triggering each response remains large ...201627557040
ubiquitin-mediated proteolysis in xenopus extract.the small protein modifier, ubiquitin, can be covalently attached to proteins in the process of ubiquitylation, resulting in a variety of functional outcomes. in particular, the most commonly-associated and well-studied fate for proteins modified with ubiquitin is their ultimate destruction: degradation by the 26s proteasome via the ubiquitin-proteasome system, or digestion in lysosomes by proteolytic enzymes. from the earliest days of ubiquitylation research, a reliable and versatile "cell-in-a ...201627528041
reprogramming of somatic cells and nuclei by xenopus oocyte and egg extracts.differentiated somatic cells and nuclei can be reprogrammed to a pluripotent undifferentiated state in the cytoplasm of oocytes and eggs. the ability of the gamete cells to induce reprogramming is not species-specific, so the extracts prepared from the oocytes and eggs of the african clawed frog xenopus laevis can reprogram somatic mammalian cells. thus, xenopus egg extract-mediated reprogramming may constitute an alternative or complement other experimental reprogramming approaches, such as nuc ...201627251073
cell-free xenopus egg extracts for studying dna damage response pathways.in response to a variety of dna replication stress or dna damaging agents, the dna damage response (ddr) pathways are triggered for cells to coordinate dna repair, cell cycle checkpoints, apoptosis, and senescence. cell-free xenopus egg extracts, derived from the eggs of african clawed frogs (xenopus laevis), have been widely used for studies concerning ddr pathways. in this review, we focus on how different experimental systems have been established using xenopus egg extracts to investigate the ...201627160070
n6-methyladenosine sequencing highlights the involvement of mrna methylation in oocyte meiotic maturation and embryo development by regulating translation in xenopus laevis.during the oogenesis of xenopus laevis, oocytes accumulate maternal materials for early embryo development. as the transcription activity of the oocyte is silenced at the fully grown stage and the global genome is reactivated only by the mid-blastula embryo stage, the translation of maternal mrnas accumulated during oocyte growth should be accurately regulated. previous evidence has illustrated that the poly(a) tail length and rna binding elements mediate rna translation regulation in the oocyte ...201627613873
boric acid is reproductively toxic to adult xenopus laevis, but not endocrine active.the potential reproductive and endocrine toxicity of boric acid (ba) in the african clawed frog, xenopus laevis, was evaluated using a 30-day exposure of adult frogs. adult female and male frogs established as breeders were exposed to a culture water control and 4 target (nominal) test concentrations [5.0, 7.5, 10.0, and 15 mg boron (b)/l, equivalent to 28.5, 42.8, 57.0, and 85.5 mg ba/l] using flow-through diluter exposure system. the primary endpoints measured were adult survival, growth (weig ...201627466210
tagging of individual embryos with electronic p-chips.collecting information about biochemical processes occurring inside a single cell or embryo is traditionally done either using fluorescent dyes with microscopy or via microelectrode voltage-clamp techniques. this paper demonstrates that a more direct method - transmission of information using an electronic chip implanted in an embryo - is feasible. a light-activated microtransponder with dimensions 250 μm × 250 μm × 100 μm (a "p-chip") was implanted into a blastula-stage frog (xenopus laevis) em ...201627787762
molecular determinants of transport function in zebrafish slc34a na-phosphate transporters.the epithelial na+-coupled phosphate cotransporter family slc34a (napi-ii) is well conserved in vertebrates and plays an essential role in maintaining whole body levels of inorganic phosphate (pi). a three-dimensional model of the transport protein has recently been proposed with defined substrate coordination sites. zebrafish express two napi-ii isoforms with high sequence identity but a 10-fold different apparent km for pi ([formula: see text]). we took advantage of the two zebrafish isoforms ...201627784684
survival fraction and phenotype alterations of xenopus laevis embryos at 3 gy, 150 kv x-ray irradiation.to determine the radiosensitivity of xenopus laevis embryos, aquatic organism model, for toxicity studies utilizing x-rays at acute high dose levels, by analysing its survival fraction and phenotype alterations under one-exposure integral dose. we used the standard frog embryo teratogenesis assay xenopus test during the early stages of x. laevis development. the embryos were harvested until st. 46 when they were irradiated. the radiation effects were checked daily for a week and the survival, ma ...201627793665
acute phase response in amputated tail stumps and neural tissue-preferential expression in tail bud embryos of the xenopus neuronal pentraxin i gene.regeneration of lost organs involves complex processes, including host defense from infection and rebuilding of lost tissues. we previously reported that xenopus neuronal pentraxin i (xnp1) is expressed preferentially in regenerating xenopus laevis tadpole tails. to evaluate xnp1 function in tail regeneration, and also in tail development, we analyzed xnp1 expression in tailbud embryos and regenerating/healing tails following tail amputation in the 'regeneration' period, as well as in the 'refra ...201627804121
tril targets smad7 for degradation to allow hematopoietic specification in xenopus embryos.in xenopus laevis, bone morphogenetic proteins (bmps) induce expression of the transcription factor gata2 during gastrulation, and gata2 is required in both ectodermal and mesodermal cells to enable mesoderm to commit to a hematopoietic fate. here, we identify tril as a gata2 target gene that is required in both ectoderm and mesoderm for primitive hematopoiesis to occur. tril is a transmembrane protein that functions as a co-receptor for toll-like receptors to mediate innate immune responses in ...201627633996
functional assessment of slc4a11, an integral membrane protein mutated in corneal dystrophies.slc4a11, a member of the slc4 family of bicarbonate transporters, is a widely expressed integral membrane protein, abundant in kidney and cornea. mutations of slc4a11 cause some cases of the blinding corneal dystrophies, congenital hereditary endothelial dystrophy, and fuchs endothelial corneal dystrophy. these diseases are marked by fluid accumulation in the corneal stroma, secondary to defective fluid reabsorption by the corneal endothelium. the role of slc4a11 in these corneal dystrophies is ...201627558157
effects of the biocide methylisothiazolinone on xenopus laevis wound healing and tail regeneration.the south african clawed frog, xenopus laevis, has a strong history as a suitable model for environmental studies. its embryos and transparent tadpoles are highly sensitive to the environment and their developmental processes are well described. it is also amenable for molecular studies. these characteristics enable its use for rapid identification and understanding of exposure-induced defects. to investigate the consequences of chemical exposure on aquatic animals, xenopus laevis embryos and ta ...201627810491
data on micrornas and microrna-targeted mrnas in xenopus ectoderm.small rnas from early neural (i.e., noggin-expressing, or nog) and epidermal (expressing a constitutively active bmp4 receptor, cabr) ectoderm in xenopus laevis were sequenced to identify micrornas (mirs) expressed in each tissue. argonaute-associated mrnas were isolated and sequenced to identify genes that are regulated by micrornas in these tissues. interactions between these ectodermal mirs and selected mir-regulated mrnas were predicted using the pita algorithm; pita predictions for over 600 ...201627812534
gulo acts as a de novo marker for pronephric tubules in xenopus laevis.vitamin c is an antioxidant and acts as a cofactor for several key enzymatic catalytic reactions in animals. amphibians produce vitamin c in their kidneys, as opposed to mammals that produce vitamin c in their liver. gulo serves as a crucial enzyme for vitamin c synthesis in mammals, but the characteristics and localization of its homologous genes during kidney development in xenopus laevis, an amphibian, remains unknown.201627832650
early bioelectric activities mediate redox-modulated regeneration.reactive oxygen species (ros) and electric currents modulate regeneration; however, the interplay between biochemical and biophysical signals during regeneration remains poorly understood. we investigate the interactions between redox and bioelectric activities during tail regeneration in xenopus laevis tadpoles. we show that inhibition of nadph oxidase-mediated production of ros, or scavenging or blocking their diffusion into cells, impairs regeneration and consistently regulates the dynamics o ...201627827821
knock-down of a tonoplast localized low-affinity nitrate transporter osnpf7.2 affects rice growth under high nitrate supply.the large nitrate transporter 1/peptide transporter family (npf) has been shown to transport diverse substrates, including nitrate, amino acids, peptides, phytohormones, and glucosinolates. however, the rice (oryza sativa) root-specific family member osnpf7.2 has not been functionally characterized. here, our data show that osnpf7.2 is a tonoplast localized low-affinity nitrate transporter, that affects rice growth under high nitrate supply. expression analysis showed that osnpf7.2 was mainly ex ...201627826301
two p2x1 receptor transcripts able to form functional channels are present in most human monocytes.to characterize the presence and general properties of p2x1 receptors in single human monocytes we used rt-pcr, flow cytometry, and the patch-clamp and the two-electrode voltage-clamp techniques. most human monocytes expressed the canonical p2x1 (90%) and its splicing variant p2x1del (88%) mrnas. p2x1 receptor immunoreactivity was also observed in 70% of these cells. currents mediated by p2x1 (ec50=1.9±0.8µm) and p2x1del (ec50 >1000µm) channels, expressed in xenopus leavis oocytes, have differen ...201627823931
from cytoskeletal dynamics to organ asymmetry: a nonlinear, regulative pathway underlies left-right patterning.consistent left-right (lr) asymmetry is a fundamental aspect of the bodyplan across phyla, and errors of laterality form an important class of human birth defects. its molecular underpinning was first discovered as a sequential pathway of left- and right-sided gene expression that controlled positioning of the heart and visceral organs. recent data have revised this picture in two important ways. first, the physical origin of chirality has been identified; cytoskeletal dynamics underlie the asym ...201627821521
soybean tip gene family analysis and characterization of gmtip1;5 and gmtip2;5 water transport activity.soybean, one of the most important crops worldwide, is severely affected by abiotic stress. drought and flooding are the major abiotic stresses impacting soybean yield. in this regard, understanding water uptake by plants, its utilization and transport has great importance. in plants, water transport is mainly governed by channel forming aquaporin proteins (aqps). tonoplast intrinsic proteins (tips) belong to the plant-specific aqp subfamily and are known to have a role in abiotic stress toleran ...201627818669
the biosynthetic gene cluster for the cyanogenic glucoside dhurrin in sorghum bicolor contains its co-expressed vacuolar mate transporter.genomic gene clusters for the biosynthesis of chemical defence compounds are increasingly identified in plant genomes. we previously reported the independent evolution of biosynthetic gene clusters for cyanogenic glucoside biosynthesis in three plant lineages. here we report that the gene cluster for the cyanogenic glucoside dhurrin in sorghum bicolor additionally contains a gene, sbmate2, encoding a transporter of the multidrug and toxic compound extrusion (mate) family, which is co-expressed w ...201627841372
dietary exposure to polybrominated diphenyl ether 47 (bde-47) inhibits development and alters thyroid hormone-related gene expression in the brain of xenopus laevis tadpoles.few studies have investigated the thyroid-disrupting effects of polybrominated diphenyl ethers (pbdes) across multiple levels of biological organization in anurans, despite their suitability for the screening of thyroid disruptors. therefore, the present study evaluated the effects of 2,2',4,4'-tetrabromodiphenyl ether (bde-47) on development, thyroid histology and thyroid hormone-related gene expression in xenopus laevis exposed to 0 (control), 50 (low), 500 (medium) or 5000μg bde-47/g food (hi ...201627838513
cohesin acetylation and wapl-pds5 oppositely regulate translocation of cohesin along dna.cohesin is a ring-shaped protein complex that plays a crucial role in sister chromatid cohesion and gene expression. the dynamic association of cohesin with chromatin is essential for these functions. however, the exact nature of cohesin dynamics, particularly cohesin translocation, remains unclear. we evaluated the dynamics of individual cohesin molecules on dna and found that the cohesin core complex possesses an intrinsic ability to traverse dna in an adenosine triphosphatase (atpase)-depende ...201627872142
foxn4 promotes gene expression required for the formation of multiple motile cilia.multiciliated cell (mcc) differentiation involves extensive organelle biogenesis required to extend hundreds of motile cilia. key transcriptional regulators known to drive the gene expression required for this organelle biogenesis are activated by the related coiled-coil proteins multicilin and gemc1. here we identify foxn4 as a new downstream target of multicilin required for mcc differentiation in xenopus skin. when foxn4 activity is inhibited in xenopus embryos, mccs show transient ciliogenes ...201627864379
2h-nmr and md simulations reveal membrane-bound conformation of magainin 2 and its synergy with pgla.magainin 2 (mag2) and pgla are two α-helical antimicrobial peptides found in the skin of the african frog xenopus laevis. they act by permeabilizing bacterial membranes and exhibit an exemplary synergism. here, we determined the detailed molecular alignment and dynamical behavior of mag2 in oriented lipid bilayers by using 2h-nmr on ala-d3-labeled peptides, which yielded orientation-dependent quadrupolar splittings of the labels. the amphiphilic mag2 helix was found to lie flat on the membrane s ...201627851939
afm visualization of sub-50nm polyplex disposition to the nuclear pore complex without compromising the integrity of the nuclear envelope.it has been questioned as to whether polyplexes in the cytoplasm can reach the nuclear compartment and if so in what form. by applying atomic force microscopy (afm) to the nuclear envelope and the nuclear pore complexes, we demonstrate that disposition of polyethylenimine (pei)/dna polyplexes that were microinjected into the oocytes of xenopus laevis, as an example of a non-dividing cell, is exclusive to the nuclear pore complex (npc). afm images show npcs clogged only with sub-50nm polyplexes. ...201627845193
β-klotho as a negative regulator of the peptide transporters pept1 and pept2.β-klotho, a transmembrane protein expressed in several tissues including the brain and the kidney, is critically important for inhibition of 1,25(oh)2d3 formation by fgf23. the extracellular domain of klotho protein could be cleaved off, thus being released into blood or cerebrospinal fluid. soluble klotho is a β-glucuronidase participating in the regulation of several ion channels and carriers. the present study explored the effect of β-klotho protein on the peptide transporters pept1 and pept2 ...201627941311
cellular encoding of cy dyes for single-molecule imaging.a general method is described for the site-specific genetic encoding of cyanine dyes as non-canonical amino acids (cy-ncaas) into proteins. the approach relies on an improved technique for nonsense suppression with in vitro misacylated orthogonal trna. the data show that cy-ncaas (based on cy3 and cy5) are tolerated by the eukaryotic ribosome in cell-free and whole-cell environments and can be incorporated into soluble and membrane proteins. in the context of the xenopus laevis oocyte expression ...201627938668
thermal ecological physiology of native and invasive frog species: do invaders perform better?biological invasions are recognized as an important biotic component of global change that threatens the composition, structure and functioning of ecosystems, resulting in loss of biodiversity and displacement of native species. although ecological characteristics facilitating the establishment and spread of non-native species are widely recognized, little is known about organismal attributes underlying invasion success. in this study, we tested the effect of thermal acclimation on thermal toler ...201627933168
development of erythroid progenitors under erythropoietin stimulation in xenopus laevis larval liver.erythroid progenitors that respond to erythropoietin (epo) are present in the liver of adult xenopus laevis. however, cells responding to epo in the larval liver and through the metamorphosis period under hepatic remodeling have not been characterized. in this study, tadpoles were staged using the tables of nieuwkoop and faber (nf). liver cells from pre- (nf56) or post- (nf66) metamorphic stage were cultured in the presence of epo. β2-globin mrna expression peaked at day 7 after the start of cul ...201627927101
regulation of human cardiac potassium channels by full-length kcne3 and kcne4.voltage-gated potassium (kv) channels comprise pore-forming α subunits and a multiplicity of regulatory proteins, including the cardiac-expressed and cardiac arrhythmia-linked transmembrane kcne subunits. after recently uncovering novel, n-terminally extended (l) kcne3 and kcne4 isoforms and detecting their transcripts in human atrium, reported here are their functional effects on human cardiac kv channel α subunits expressed in xenopus laevis oocytes. as previously reported for short isoforms k ...201627922120
pth1r mutants found in patients with primary failure of tooth eruption disrupt g-protein signaling.primary failure of tooth eruption (pfe) is causally linked to heterozygous mutations of the parathyroid hormone receptor (pth1r) gene. the mutants described so far lead to exchange of amino acids or truncation of the protein that may result in structural changes of the expressed pth1r. however, functional effects of these mutations have not been investigated yet.201627898723
sgk3 sensitivity of large-conductance ca2+-activated k+ channel.large conductance ca2+-activated k+ channels (maxi k+ channels or bk channels) are rapidly activated by increase of cytosolic ca2+ activity. the channels participate in the regulation of diverse functions including neuronal excitation and cell volume. the bk channels may be modified by kinases. channel regulating kinases include the serum & glucocorticoid inducible kinase 3 (sgk3). the present study explored whether sgk3 modifies the activity of bk channels.201627898416
replication, checkpoint suppression and structure of centromeric dna.human centromeres contain large amounts of repetitive dna sequences known as α satellite dna, which can be difficult to replicate and whose functional role is unclear. recently, we have characterized protein composition, structural organization and checkpoint response to stalled replication forks of centromeric chromatin reconstituted in xenopus laevis egg extract. we showed that centromeric dna has high affinity for smc2-4 subunits of condensins and for cenp-a, it is enriched for dna repair fac ...201627893298
ventx induces expansion of primitive erythroid cells and contributes to the development of acute myeloid leukemia in mice.homeobox genes are key regulators in normal and malignant hematopoiesis. the human vent-like homeobox gene ventx, a putative homolog of the xenopus laevis xvent-2 gene, was shown to be highly expressed in normal myeloid cells and in patients with acute myeloid leukemia. we now demonstrate that constitutive expression of ventx suppresses expression of genes responsible for terminal erythroid differentiation in normal cd34+ stem and progenitor cells. transplantation of bone marrow progenitor cells ...201627888632
down-regulation of the na+,cl- coupled creatine transporter creat (slc6a8) by glycogen synthase kinase gsk3ß.the na+,cl- coupled creatine transporter creat (slc6a8) is expressed in a variety of tissues including the brain. genetic defects of creat lead to mental retardation with seizures. the present study explored the regulation of creat by the ubiquitously expressed glycogen synthase kinase gsk3ß, which contributes to the regulation of neuroexcitation. gsk3ß is phosphorylated and thus inhibited by pkb/akt. moreover, gsk3ß is inhibited by the antidepressant lithium. the present study thus further test ...201627978525
a markovian entropy measure for the analysis of calcium activity time series.methods to analyze the dynamics of calcium activity often rely on visually distinguishable features in time series data such as spikes, waves, or oscillations. however, systems such as the developing nervous system display a complex, irregular type of calcium activity which makes the use of such methods less appropriate. instead, for such systems there exists a class of methods (including information theoretic, power spectral, and fractal analysis approaches) which use more fundamental propertie ...201627977764
regulation of photoreceptor gene transcription via a highly conserved transcriptional regulatory element by vsx gene products.the photoreceptor conserved element-1 (pce-1) sequence is found in the transcriptional regulatory regions of many genes expressed in photoreceptors. the retinal homeobox (rx or rax) gene product functions by binding to pce-1 sites. however, other transcriptional regulators have also been reported to bind to pce-1. one of these, vsx2, is expressed in retinal progenitor and bipolar cells. the purpose of this study is to identify xenopus laevis vsx gene products and characterize vsx gene product ex ...201628003732
the natural plant product rottlerin activates kv7.1/kcne1 channels.acquired as well as inherited channelopathies are disorders that are caused by altered ion channel function. a family of channels whose malfunction is associated with different channelopathies is the kv7 k+ channel family; and restoration of normal kv7 channel function by small molecule modulators is a promising approach for treatment of these often fatal diseases.201627997884
roles of aquaporins in setaria viridis stem development and sugar storage.setaria viridis is a c4 grass used as a model for bioenergy feedstocks. the elongating internodes in developing s. viridis stems grow from an intercalary meristem at the base, and progress acropetally toward fully expanded cells that store sugar. during stem development and maturation, water flow is a driver of cell expansion and sugar delivery. as aquaporin proteins are implicated in regulating water flow, we analyzed elongating and mature internode transcriptomes to identify putative aquaporin ...201628018372
cell repair: revisiting the patch hypothesis.plasma membrane damage elicits a complex and dynamic cellular response. a vital component of this response, membrane resealing, is thought to arise from fusion of intracellular membranous compartments to form a temporary, impermeant patch at the site of damage; however, this hypothesis has been difficult to confirm visually. by utilizing advanced microscopy technologies with high spatiotemporal resolution in wounded xenopus laevis oocytes, we provide the first direct visualization of the membran ...201628042380
variability of rheotaxis behaviors in larval bullfrogs highlights species diversity in lateral line function.the morphology and distribution of lateral line neuromasts vary between ecomorphological types of anuran tadpoles, but little is known about how this structural variability contributes to differences in lateral-line mediated behaviors. previous research identified distinct differences in one such behavior, positive rheotaxis towards the source of a flow, in two tadpole species, the african clawed frog (xenopus laevis; type 1) and the american bullfrog (rana catesbeiana; type 4). because these tw ...201627870909
characterisation and vascular expression of nitric oxide synthase 3 in amphibians.in mammals, nitric oxide (no) produced by nitric oxide synthase 3 (nos3) localised in vascular endothelial cells is an important vasodilator but the presence of nos3 in the endothelium of amphibians has been concluded to be absent, based on physiological studies. in this study, a nos3 cdna was sequenced from the toad, rhinella marina. the open reading frame of r. marina nos3 encoded an 1170 amino acid protein that showed 81 % sequence identity to the recently cloned xenopus tropicalis nos3. rhin ...201627543051
peptidomic analysis of the extensive array of host-defense peptides in skin secretions of the dodecaploid frog xenopus ruwenzoriensis (pipidae).the uganda clawed frog xenopus ruwenzoriensis with a karyotype of 2n=108 is one of the very few vertebrates with dodecaploid status. peptidomic analysis of norepinephrine-stimulated skin secretions from this species led to the isolation and structural characterization of 23 host-defense peptides belonging to the following families: magainin (3 peptides), peptide glycine-leucine-amide (pgla; 6 peptides), xenopsin precursor fragment (xpf; 3 peptides), caerulein precursor fragment (cpf; 8 peptides) ...201627290612
quantification of 11 thyroid hormones and associated metabolites in blood using isotope-dilution liquid chromatography tandem mass spectrometry.this paper describes a novel analytical methodology for the simultaneous determination of absolute and total concentrations of 11 native thyroid hormones and associated metabolites, viz. thyroxine (t4), 3,3', 5-triiodothyronine (t3), 3,3', 5'-triiodothyronine (rt3), 3,5-diiodothyronine (3,5-t2), 3,3'- diiodothyronine (3,3'-t2), 3-iodothyronine (t1), thyronine (t0), 3-iodothyronamine (t1am), tetraiodothyroacetic acid (tetrac), triiodothyroacetic acid (triac), and diiodothyroacetic acid (diac), in ...201627215639
increased androgenic sensitivity in the hind limb muscular system marks the evolution of a derived gestural display.physical gestures are prominent features of many species' multimodal displays, yet how evolution incorporates body and leg movements into animal signaling repertoires is unclear. androgenic hormones modulate the production of reproductive signals and sexual motor skills in many vertebrates; therefore, one possibility is that selection for physical signals drives the evolution of androgenic sensitivity in select neuromotor pathways. we examined this issue in the bornean rock frog (staurois parvus ...201627143723
transcription factors mix1 and vegt, relocalization of vegt mrna, and conserved endoderm and dorsal specification in frogs.protein expression of the transcription factor genes mix1 and vegt characterized the presumptive endoderm in embryos of the frogs engystomops randi, epipedobates machalilla, gastrotheca riobambae, and eleutherodactylus coqui, as in xenopus laevis embryos. protein vegt was detected in the animal hemisphere of the early blastula in all frogs, and only the animal pole was vegt-negative. this finding stimulated a vegt mrna analysis in x. laevis eggs and embryos. vegt mrna was detected in the animal ...201627140624
frogs as integrative models for understanding digestive organ development and evolution.the digestive system comprises numerous cells, tissues and organs that are essential for the proper assimilation of nutrients and energy. many aspects of digestive organ function are highly conserved among vertebrates, yet the final anatomical configuration of the gut varies widely between species, especially those with different diets. improved understanding of the complex molecular and cellular events that orchestrate digestive organ development is pertinent to many areas of biology and medici ...201626851628
transcriptome profiles of metamorphosis in the ornamented pygmy frog microhyla fissipes clarify the functions of thyroid hormone receptors in metamorphosis.anuran metamorphosis is an excellent system in which to study postembryonic development. studies on xenopus (mesobatrachia) show that thyroid hormone receptors (trs) regulate metamorphosis in a ligand-dependent manner by coordinating the action of hundreds of genes. however, whether this mechanism is conserved among amphibians is still unknown. to understand the molecular mechanism of this universal phenomenon, we report the transcriptional profiles of the three key developmental stages in micro ...201627254593
impaired gonadal and somatic development corroborate vulnerability differences to the synthetic estrogen ethinylestradiol among deeply diverged anuran lineages.amphibians are undergoing a global decline. one poorly investigated reason could be the pollution of aquatic habitats by endocrine disrupting compounds (edcs). we tested the susceptibility to the synthetically stabilized estrogen 17α-ethinylestradiol (ee2) in three deeply diverged anuran species, differing in sex determination systems, types of gonadogenesis and larval ecologies. to understand whether data from the amphibian model xenopus laevis (pipidae) are analogous and applicable to only dis ...201627434076
the plasticizer bisphenol a affects somatic and sexual development, but differently in pipid, hylid and bufonid anurans.due to their terrestrial habitats and aquatic reproduction, many amphibians are both very vulnerable and highly suitable bioindicators. the plasticizer bisphenol a (bpa) is one of the most produced chemical substances worldwide, and knowledge on its impacts on humans and animals is mounting. bpa is used for the industrial production of polycarbonate plastics and epoxy resins and found in a multitude of consumer products. studies on bpa have involved mammals, fish and the fully aquatic anuran mod ...201627285164
sex reversal assessments reveal different vulnerability to endocrine disruption between deeply diverged anuran lineages.multiple anthropogenic stressors cause worldwide amphibian declines. among several poorly investigated causes is global pollution of aquatic ecosystems with endocrine disrupting compounds (edcs). these substances interfere with the endocrine system and can affect the sexual development of vertebrates including amphibians. we test the susceptibility to an environmentally relevant contraceptive, the artificial estrogen 17α-ethinylestradiol (ee2), simultaneously in three deeply divergent systematic ...201627029458
integrated assessment of biochemical markers in premetamorphic tadpoles of three amphibian species exposed to glyphosate- and methidathion-based pesticides in single and combination forms.in this study, we evaluated the toxic effects of a glyphosate-based herbicide (gbh) and a methidathion-based insecticide (mbi), individually and in combination, on premetamorphic tadpoles of three anuran species: pelophylax ridibundus, xenopus laevis, and bufotes viridis. based on the determined 96-h lc50 values of each species, the effects of a series of sublethal concentrations of single pesticides and their mixtures after 96-h exposure and also the time-related effects of a high sublethal con ...201626595308
testing the evolutionary conservation of vocal motoneurons in vertebrates.medullary motoneurons drive vocalization in many vertebrate lineages including fish, amphibians, birds, and mammals. the developmental history of vocal motoneuron populations in each of these lineages remains largely unknown. the highly conserved transcription factor paired-like homeobox 2b (phox2b) is presumed to be expressed in all vertebrate hindbrain branchial motoneurons, including laryngeal motoneurons essential for vocalization in humans. we used immunohistochemistry and in situ hybridiza ...201626160673
a novel method to verify multilevel computational models of biological systems using multiscale spatio-temporal meta model checking.insights gained from multilevel computational models of biological systems can be translated into real-life applications only if the model correctness has been verified first. one of the most frequently employed in silico techniques for computational model verification is model checking. traditional model checking approaches only consider the evolution of numeric values, such as concentrations, over time and are appropriate for computational models of small scale systems (e.g. intracellular netw ...201627187178
multicellular mathematical modelling of mesendoderm formation in amphibians.the earliest cell fate decisions in a developing embryo are those associated with establishing the germ layers. the specification of the mesoderm and endoderm is of particular interest as the mesoderm is induced from the endoderm, potentially from an underlying bipotential group of cells, the mesendoderm. mesendoderm formation has been well studied in an amphibian model frog, xenopus laevis, and its formation is driven by a gene regulatory network (grn) induced by maternal factors deposited in t ...201626934886
effects of ginseng-spikenard heart-nourishing capsule on inactivation of c-type kv1.4 potassium channel.this research is to explore the effects of traditional chinese medicine ginseng-spikenard heart-nourishing capsule on the inactivation of c-type kv1.4 channels (kv1.4∆n) in xenopus laevis oocytes with two-electrode voltageclamp technique. defolliculated oocytes (stage v-vi) were injected with transcribed crnas of ferret kv1.4δn channels. during recording, oocytes were continuously perfused with nd96 solution (control group) and solution prepared from ginseng-spikenard heart-nourishing capsule (e ...201627731805
xenopus laevis nkx5.3 and sensory organ homeobox (soho) are expressed in developing sensory organs and ganglia of the head and anterior trunk.nkx5 family members are homeobox transcription factors important for sensory organ development. several members of the nkx5 family are expressed in the eye, brain, developing ear, and lateral line. members of this family have been previously identified in medaka, chick, and mouse. here, we characterize two members of the nkx5 family, nkx5.3 and soho, in xenopus laevis. we verify the identity of x. laevis nkx5.3 and soho by phylogenetic comparison to chicken, medaka, and zebrafish orthologs. both ...201627392729
cug-bp, elav-like family member 1 (celf1) is required for normal myofibrillogenesis, morphogenesis, and contractile function in the embryonic heart.cug-bp, elav-like family member 1 (celf1) is a multifunctional rna binding protein found in a variety of adult and embryonic tissues. in the heart, celf1 is found exclusively in the myocardium. however, the roles of celf1 during cardiac development have not been completely elucidated.201627144987
xenopus limb bud morphogenesis.xenopus laevis, the south african clawed frog, is a well-established model organism for the study of developmental biology and regeneration due to its many advantages for both classical and molecular studies of patterning and morphogenesis. while contemporary studies of limb development tend to focus on models developed from the study of chicken and mouse embryos, there are also many classical studies of limb development in frogs. these include both fate and specification maps, that, due to thei ...201626404044
[evolutional principles of homology in regulatory genes of myogenesis].analysis of early steps in muscular system development of invertebrates and vertebrates shows that early steps of myogenesis are regulated by genes-orthologs mainly belonging to two families, pax and bhlh. in the majority of the following organisms, muscles formation (steps of determination and the earliest steps of myogenesis) is regulated by genes orthologs pax3 which belong to the family pax: nematodes (caenorhabditis elegans, pristionchus pacificus), insects (drosophila melanogaster), echino ...201622988754
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 ...201625482090
gene duplications and losses among vertebrate deoxyribonucleoside kinases of the non-tk1 family.deoxyribonucleoside kinases (dnks) salvage deoxyribonucleosides (dns) and catalyze the rate limiting step of this salvage pathway by converting dns into corresponding monophosphate forms. these enzymes serve as an excellent model to study duplicated genes and their evolutionary history. so far, among vertebrates only four mammalian dnks have been studied for their substrate specificity and kinetic properties. however, some vertebrates, such as fish, frogs, and birds, apparently possess a duplica ...201627906638
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 ...201625382697
rattlesnake phospholipase a2 increases cftr-chloride channel current and corrects ∆f508cftr dysfunction: impact in cystic fibrosis.deletion of phe508 in the nucleotide binding domain (∆f508-nbd1) of the cystic fibrosis transmembrane regulator (cftr; a cyclic amp-regulated chloride channel) is the most frequent mutation associated with cystic fibrosis. this mutation affects the maturation and gating of cftr protein. the search for new high-affinity ligands of cftr acting as dual modulators (correctors/activators) presents a major challenge in the pharmacology of cystic fibrosis. snake venoms are a rich source of natural mult ...201627241308
an investigation of the differential effects of ursane triterpenoids from centella asiatica, and their semisynthetic analogues, on gabaa receptors.the ursane triterpenoids, asiatic acid 1 and madecassic acid 2, are the major pharmacological constituents of centella asiatica, commonly known as gotu kola, which is used traditionally for the treatment of anxiety and for the improvement of cognition and memory. using the two-electrode voltage-clamp technique, these triterpenes, and some semisynthetic derivatives, were found to exhibit selective negative modulation of different subtypes of the gabaa receptor expressed in xenopus laevis oocytes. ...201627062315
amino acid transporter b(0)at1 (slc6a19) and ancillary protein: impact on function.amino acids play an important role in the metabolism of all organisms. their epithelial re-absorption is due to specific transport proteins, such as b(0)at1, a na(+)-coupled neutral amino acid symporter belonging to the solute carrier 6 family. here, a recently cloned fish orthologue, from the intestine of salmo salar, was electrophysiologically characterized with the two-electrode voltage clamp technique, in xenopus laevis oocytes heterologously expressing the transporter. substrate specificity ...201627255547
discrete mesh approach in morphogenesis modelling: the example of gastrulation.morphogenesis is a general concept in biology including all the processes which generate tissue shapes and cellular organizations in a living organism. many hybrid formalizations (i.e., with both discrete and continuous parts) have been proposed for modelling morphogenesis in embryonic or adult animals, like gastrulation. we propose first to study the ventral furrow invagination as the initial step of gastrulation, early stage of embryogenesis. we focus on the study of the connection between the ...201627853896
alanine to valine substitutions in the pore helix iiip1 and linker-helix iiil45 confer cockroach sodium channel resistance to ddt and pyrethroids.pyrethroid insecticides exert toxic effects by prolonging the opening of voltage-gated sodium channels. more than 20 sodium channel mutations from arthropod pests and disease vectors have been confirmed to confer pyrethroid resistance. these mutations have been valuable in elucidating the molecular interaction between pyrethroids and sodium channels, including identification of two pyrethroid receptor sites. previously, two alanine to valine substitutions, one in the pore helix iiip1 and the oth ...201627328896
conservation in the involvement of heterochronic genes and hormones during developmental transitions.developmental transitions include molting in some invertebrates and the metamorphosis of insects and amphibians. while the study of caenorhabditis elegans larval transitions was crucial to determine the genetic control of these transitions, drosophila melanogaster and xenopus laevis have been classic models to study the role of hormones in metamorphosis. here we review how heterochronic genes (lin-4, let-7, lin-28, lin-41), hormones (dafachronic acid, ecdysone, thyroid hormone) and the environme ...201627297887
ric-3 expression and splicing regulate nachr functional expression.the nicotinic acetylcholine receptors form a large and diverse family of acetylcholine gated ion channels having diverse roles in the central nervous system. maturation of nicotinic acetylcholine receptors is a complex and inefficient process requiring assistance from multiple cellular factors including ric-3, a functionally conserved endoplasmic reticulum-resident protein and nicotinic acetylcholine receptor-specific chaperone. in mammals and in drosophila melanogaster ric-3 is alternatively sp ...201627129882
conserved roles for cytoskeletal components in determining laterality.consistently-biased left-right (lr) patterning is required for the proper placement of organs including the heart and viscera. the lr axis is especially fascinating as an example of multi-scale pattern formation, since here chiral events at the subcellular level are integrated and amplified into asymmetric transcriptional cascades and ultimately into the anatomical patterning of the entire body. in contrast to the other two body axes, there is considerable controversy about the earliest mechanis ...201626928161
molecular cloning and expression of a gaba receptor subunit from the crayfish procambarus clarkii.molecular cloning has introduced an unexpected, large diversity of neurotransmitter hetero- oligomeric receptors. extensive research on the molecular structure of the γ-aminobutyric acid receptor (gabar) has been of great significance for understanding how the nervous system works in both vertebrates and invertebrates. however, only two examples of functional homo-oligomeric gaba-activated cl(-) channels have been reported. in the vertebrate retina, the gabaρ1 subunit of various species forms ho ...201626577600
sulfate and thiosulfate inhibit oxalate transport via a dprestin (slc26a6)-dependent mechanism in an insect model of calcium oxalate nephrolithiasis.nephrolithiasis is one of the most common urinary tract disorders, with the majority of kidney stones composed of calcium oxalate (caox). given its prevalence (us occurrence 10%), it is still poorly understood, lacking progress in identifying new therapies because of its complex etiology. drosophila melanogaster (fruitfly) is a recently developed model of caox nephrolithiasis. effects of sulfate and thiosulfate on crystal formation were investigated using the drosophila model, as well as electro ...201626538444
histone h2b gene cloning, with implication for its function during nuclear shaping in the chinese mitten crab, eriocheir sinensis.spermatogenesis in animals is the process by which male spermatogonia develop into mature spermatozoa. in most taxa, the process involves changes in the basic proteins associated with dna. somatic-type histones are partially or totally replaced by transition proteins, which in turn are replaced by protamines producing compact packaging of the genome. sperm chromatin in the chinese mitten crab (eriocheir sinensis) has a noncompacted loosely arranged organization. however, its formation during spe ...201626343795
tob1 is expressed in developing and adult gonads and is associated with the p-body marker, dcp2.tob1 is a member of the btg/tob family of proteins with established antiproliferative function. in danio rerio and xenopus laevis, the tob1 gene is expressed from the one-cell stage through to early gastrula stages, followed in later development by discrete expression in many tissues including the notochord and somites. in both mouse and human, tob1 is expressed in many adult tissues including the testis and ovary; however, the specific cell types are unknown. we examine tob1 gene expression in ...201626662055
luteinizing hormone is an effective replacement for hcg to induce ovulation in xenopus.injection of human chorionic gonadotropin (hcg) directly into the dorsal lymph sac of xenopus is a commonly used protocol for induction of ovulation, but recent shortages in the stocks of commercially available hcg as well as lack of a well tested alternative have resulted in frustrating experimental delays in laboratories that predominantly use xenopus in their research. mammalian luteinizing hormones (lh) share structural similarity, functional equivalency, and bind the same receptor as hcg; t ...201627263125
purification and fluorescent labeling of tubulin from xenopus laevis egg extracts.for many years, microtubule research has depended on tubulin purified from cow and pig brains, which may not be ideal for experiments using proteins or extracts from non-brain tissues and cold-blooded organisms. here, we describe a method to purify functional tubulin from the eggs of the frog, xenopus laevis. this tubulin has many benefits for the study of microtubules and microtubule based structures assembled in vitro at room temperature. frog tubulin lacks many of the highly stabilizing postt ...201627193841
retinoic acid homeostasis regulates meiotic entry in developing anuran gonads and in bidder's organ through raldh2 and cyp26b1 proteins.the vitamin a (retinol) and its metabolites such as retinoic acid (ra) affect vertebrate gametogenesis. the level of ra in cells relies on the balance between its synthesis and degradation. the sex-dependent equilibrium is reached in different ways in various species. it is known that ra induces meiosis in developing gonads in mouse, chicken and urodel amphibians, but its role in anuran amphibians has not been studied. here we show in six anuran species (xenopus laevis, bombina bombina, hyla arb ...201624056063
distribution of single wall carbon nanotubes in the xenopus laevis embryo after microinjection.single wall carbon nanotubes (swcnts) are advanced materials with the potential for a myriad of diverse applications, including biological technologies and large-scale usage with the potential for environmental impacts. swcnts have been exposed to developing organisms to determine their effects on embryogenesis, and results have been inconsistent arising, in part, from differing material quality, dispersion status, material size, impurity from catalysts and stability. for this study, we utilized ...201626510384
ddt exposure of frogs: a case study from limpopo province, south africa.amphibians are globally under pressure with environmental contaminants contributing to this. despite caution aired more than 80 years ago of threats posed to amphibians by ddt spraying for disease vector control, no data have been published on concentrations or effects of ddt contamination in frogs from areas where ddt is actively sprayed to control the insect vectors of malaria. in this study, we sampled fat bodies of xenopus laevis and xenopus muelleri naturally occurring in an area where indo ...201627317939
cloning and functional expression of intracellular loop variants of the honey bee (apis mellifera) rdl gaba receptor.the insect gaba receptor, rdl (resistance to dieldrin), plays central roles in neuronal signalling and is the target of several classes of insecticides. to study the gaba receptor from an important pollinator species, we cloned rdl cdna from the honey bee, apis mellifera. three rdl variants were identified, arising from differential use of splice acceptor sites in the large intracellular loop between transmembrane regions 3 and 4. these variants were renamed from previously, as amel_rdlvar1, ame ...201627288983
a dominant mutation in the ht1 kinase uncovers roles of map kinases and ghr1 in co2-induced stomatal closure.activation of the guard cell s-type anion channel slac1 is important for stomatal closure in response to diverse stimuli, including elevated co2 the majority of known slac1 activation mechanisms depend on abscisic acid (aba) signaling. several lines of evidence point to a parallel aba-independent mechanism of co2-induced stomatal regulation; however, molecular details of this pathway remain scarce. here, we isolated a dominant mutation in the protein kinase high leaf temperature1 (ht1), an essen ...201627694184
research advances on animal genetics in china in 2015.chinese scientists have made significant achievements in the field of animal genetics in 2015. incomplete statistics show that among all the publications of 2015 involving nematode (caenorhabditis elegans), fly (drosophila melanogaster), zebrafish (danio rerio), african clawed frog (xenopus) or mice (mus musculus), about 1/5 publications are from china. many innovative studies were published in high-impact international academic journals by chinese scientists, including the identification of a p ...201627655312
slah1, a homologue of the slow type anion channel slac1, modulates shoot cl- accumulation and salt tolerance in arabidopsis thaliana.salinity tolerance is correlated with shoot chloride (cl(-)) exclusion in multiple crops, but the molecular mechanisms of long-distance cl(-) transport are poorly defined. here, we characterize the in planta role of atslah1 (a homologue of the slow type anion channel-associated 1 (slac1)). this protein, localized to the plasma membrane of root stelar cells, has its expression reduced by salt or aba, which are key predictions for a protein involved with loading cl(-) into the root xylem. artifici ...201627340232
a chimeric protein of aluminum-activated malate transporter generated from wheat and arabidopsis shows enhanced response to trivalent cations.taalmt1 from wheat (triticum aestivum) and atalmt1 from arabidopsis thaliana encode aluminum (al)-activated malate transporters, which confer acid-soil tolerance by releasing malate from roots. chimeric proteins from taalmt1 and atalmt1 (ta::at, at::ta) were previously analyzed in xenopus laevis oocytes. those studies showed that al could activate malate efflux from the ta::at chimera but not from at::ta. here, functions of taalmt1, atalmt1 and the chimeric protein ta::at were compared in cultur ...201627039280
reconstitution of co2 regulation of slac1 anion channel and function of co2-permeable pip2;1 aquaporin as carbonic anhydrase4 interactor.dark respiration causes an increase in leaf co2 concentration (ci), and the continuing increases in atmospheric [co2] further increases ci. elevated leaf co2 concentration causes stomatal pores to close. here, we demonstrate that high intracellular co2/hco3 (-) enhances currents mediated by the arabidopsis thaliana guard cell s-type anion channel slac1 upon coexpression of any one of the arabidopsis protein kinases ost1, cpk6, or cpk23 in xenopus laevis oocytes. split-ubiquitin screening identif ...201626764375
identification of a stelar-localized transport protein that facilitates root-to-shoot transfer of chloride in arabidopsis.under saline conditions, higher plants restrict the accumulation of chloride ions (cl(-)) in the shoot by regulating their transfer from the root symplast into the xylem-associated apoplast. to identify molecular mechanisms underpinning this phenomenon, we undertook a transcriptional screen of salt stressed arabidopsis (arabidopsis thaliana) roots. microarrays, quantitative rt-pcr, and promoter-gus fusions identified a candidate gene involved in cl(-) xylem loading from the nitrate transporter 1 ...201626662602
functional validation of the carbon dioxide receptor in labial palps of helicoverpa armigera moths.adult moths possess an organ in their labial palps, the labial-palp pit organ, which is specialized for sensing carbon dioxide (co2). they use co2 as a cue to detect healthy plants and find food or lay eggs on them. the molecular bases of the co2 receptor in drosophila melanogaster and aedes aegypti have been reported, but the molecular mechanisms of the co2 receptor in lepidoptera remains elusive. in this study, we first re-examined three putative helicoverpa armigera co2 gustatory receptor gen ...201627060445
atnpf2.5 modulates chloride (cl(-)) efflux from roots of arabidopsis thaliana.the accumulation of high concentrations of chloride (cl(-)) in leaves can adversely affect plant growth. when comparing different varieties of the same cl(-) sensitive plant species those that exclude relatively more cl(-) from their shoots tend to perform better under saline conditions; however, the molecular mechanisms involved in maintaining low shoot cl(-) remain largely undefined. recently, it was shown that the nrt1/ptr family 2.4 protein (npf2.4) loads cl(-) into the root xylem, which aff ...201628111585
structures of xenopus embryonic epidermal lectin reveal a conserved mechanism of microbial glycan recognition.intelectins (x-type lectins), broadly distributed throughout chordates, have been implicated in innate immunity. xenopus laevis embryonic epidermal lectin (xeel), an intelectin secreted into environmental water by the x. laevis embryo, is postulated to function as a defense against microbes. xeel is homologous (64% identical) to human intelectin-1 (hintl-1), which is also implicated in innate immune defense. we showed previously that hintl-1 binds microbial glycans bearing exocyclic vicinal diol ...201626755729
verapamil-sensitive transport of quinacrine and methylene blue via the plasmodium falciparum chloroquine resistance transporter reduces the parasite's susceptibility to these tricyclic drugs.it is becoming increasingly apparent that certain mutations in the plasmodium falciparum chloroquine resistance transporter (pfcrt) alter the parasite's susceptibility to diverse compounds. here we investigated the interaction of pfcrt with 3 tricyclic compounds that have been used to treat malaria (quinacrine [qc] and methylene blue [mb]) or to study p. falciparum (acridine orange [ao]).201626503982
oschx14 is involved in the k+ homeostasis in rice (oryza sativa) flowers.previously we showed in the osjar1 mutants that the lodicule senescence which controls the closing of rice flowers was delayed. this resulted in florets staying open longer when compared with the wild type. the gene osjar1 is silenced in osjar1 mutants and is a key member of the jasmonic acid (ja) signaling pathway. we found that k concentrations in lodicules and flowers of osjar1-2 were significantly elevated compared with the wild type, indicating that k(+) homeostasis may play a role in regul ...201627903806
mechanism and regulation of dna-protein crosslink repair by the dna-dependent metalloprotease sprtn.covalent dna-protein crosslinks (dpcs) are toxic dna lesions that interfere with essential chromatin transactions, such as replication and transcription. little was known about dpc-specific repair mechanisms until the recent identification of a dpc-processing protease in yeast. the existence of a dpc protease in higher eukaryotes is inferred from data in xenopus laevis egg extracts, but its identity remains elusive. here we identify the metalloprotease sprtn as the dpc protease acting in metazoa ...201627871365
an evaluation of the endocrine disruptive potential of crude oil water accommodated fractions and crude oil contaminated surface water to freshwater organisms using in vitro and in vivo approaches.knowledge regarding the potential impacts of crude oil on endocrine signaling in freshwater aquatic vertebrates is limited. the expression of selected genes as biomarkers for altered endocrine signaling was studied in african clawed frog, xenopus laevis, tadpoles and juvenile mozambique tilapia, oreochromis mossambicus, exposed to weathered bunker and unweathered refinery crude oil water accommodated fractions (wafs). in addition, the expression of the aforementioned genes was quantified in x. l ...201627787904
non-selective cation channel activity of aquaporin atpip2;1 regulated by ca(2+) and ph.the aquaporin atpip2;1 is an abundant plasma membrane intrinsic protein in arabidopsis thaliana that is implicated in stomatal closure, and is highly expressed in plasma membranes of root epidermal cells. when expressed in xenopus laevis oocytes, atpip2;1 increased water permeability and induced a non-selective cation conductance mainly associated with na(+) . a mutation in the water pore, g103w, prevented both the ionic conductance and water permeability of pip2;1. co-expression of atpip2;1 wit ...201627620834
a single amino-acid substitution in the sodium transporter hkt1 associated with plant salt tolerance.a crucial prerequisite for plant growth and survival is the maintenance of potassium uptake, especially when high sodium surrounds the root zone. the arabidopsis high-affinity k(+) transporter1 (hkt1), and its homologs in other salt-sensitive dicots, contributes to salinity tolerance by removing na(+) from the transpiration stream. however, tshkt1;2, one of three hkt1 copies in thellungiella salsuginea, a halophytic arabidopsis relative, acts as a k(+) transporter in the presence of na(+) in yea ...201627208305
inositol transporters atint2 and atint4 regulate arsenic accumulation in arabidopsis seeds.arsenic contamination of groundwater and soils threatens the health of tens of millions of people worldwide. understanding the way in which arsenic is taken up by crops such as rice, which serve as a significant source of arsenic in the human diet, is therefore important. membrane transport proteins that catalyse arsenic uptake by roots, and translocation through the xylem to shoots, have been characterized in a number of plants, including rice. the transporters responsible for loading arsenic f ...201627004129
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