Publications

aquaporin expression in the alimentary canal of the honey bee apis mellifera l. (hymenoptera: apidae) and functional characterization of am_eglp 1.	aquaporins (aqp) are a family of plasma membrane proteins responsible for water transport through cell membranes. they are differentially expressed in different parts of the alimentary canal of insects where they regulate water transport. these proteins have been studied in detail in some insects, but few data are available for aquaporins of the honey bee, apis mellifera. we used quantitative pcr to study the expression of six putative aquaporin genes in forager honey bees. we found differential ...	2020	32956406
amiodarone bioconcentration and suppression of metamorphosis in xenopus.	trace concentrations of a number of pharmaceutically active compounds have been detected in the aquatic environment in many countries, where they are thought to have the potential to exert adverse effects on non-target organisms. amiodarone (amd) is one such high-risk compound commonly used in general hospitals. amd is known to alter normal thyroid hormone (th) function, although little information is available regarding the specific mechanism by which this disruption occurs. anuran tadpole meta ...	2020	32956954
endoparasites infecting exotic captive amphibian pet and zoo animals (anura, caudata) in germany.	alongside exotic reptiles, amphibians, such as toads, frogs, salamanders, and newts, are nowadays considered popular pets worldwide. as reported for other exotic pet animals, amphibians are known to harbor numerous gastrointestinal parasites. nonetheless, very little data are available on captive amphibian parasitic diseases. in this study, we applied direct saline fecal smears (dsfs) to examine in total 161 stool samples from 41 different amphibian species belonging to the orders anura and caud ...	2020	32960371
design, synthesis, and in vitro evaluation of p2x7 antagonists.	the p2x7 receptor is a promising target for the treatment of various diseases due to its significant role in inflammation and immune cell signaling. this work describes the design, synthesis, and in vitro evaluation of a series of novel derivatives bearing diverse scaffolds as potent p2x7 antagonists. our approach was based on structural modifications of reported (adamantan-1-yl)methylbenzamides able to inhibit the receptor activation. the adamantane moieties and the amide bond were replaced, an ...	2020	32964578
in-cell nmr spectroscopy of functional riboswitch aptamers in eukaryotic cells.	we report here the in-cell nmr-spectroscopic observation of the binding of the cognate ligand 2'-deoxyguanosine to the aptamer domain of the bacterial 2'-deoxyguanosine-sensing riboswitch in eukaryotic cells, namely xenopus laevis oocytes and in human hela cells. the riboswitch is sufficiently stable in both cell types to allow for detection of binding of the ligand to the riboswitch. most importantly, we show that the binding mode established by in vitro characterization of this prokaryotic rib ...	2020	32975353
the mechanism of nmda receptor hyperexcitation in high pressure helium and hyperbaric oxygen.	professional divers exposed to pressures greater than 1.1 mpa may suffer from the high pressure neurological syndrome (hpns). divers who use closed-circuit breathing apparatus face the risk of cns hyperbaric oxygen toxicity (hbotox). both syndromes are characterized by reversible cns hyperexcitability, accompanied by cognitive and motor deficits. previous studies have demonstrated that the hyperexcitability of hpns is induced mainly by nmda receptors (nmdars). in our recent studies, we demonstra ...	2020	32982789
inferring a complete genotype-phenotype map from a small number of measured phenotypes.	understanding evolution requires detailed knowledge of genotype-phenotype maps; however, it can be a herculean task to measure every phenotype in a combinatorial map. we have developed a computational strategy to predict the missing phenotypes from an incomplete, combinatorial genotype-phenotype map. as a test case, we used an incomplete genotype-phenotype dataset previously generated for the malaria parasite's 'chloroquine resistance transporter' (pfcrt). wild-type pfcrt (pfcrt3d7) lacks signif ...	2020	32991585
a survey of barley pip aquaporin ionic conductance reveals ca2+-sensitive hvpip2;8 na+ and k+ conductance.	some plasma membrane intrinsic protein (pip) aquaporins can facilitate ion transport. here we report that one of the 12 barley pips (pip1 and pip2) tested, hvpip2;8, facilitated cation transport when expressed in xenopus laevis oocytes. hvpip2;8-associated ion currents were detected with na+ and k+, but not cs+, rb+, or li+, and was inhibited by ba2+, ca2+, and cd2+ and to a lesser extent mg2+, which also interacted with ca2+. currents were reduced in the presence of k+, cs+, rb+, or li+ relativ ...	2020	32992595
torc1 selectively regulates synaptic maturation and input convergence in the developing visual system.	newly synthesized proteins support the development of functional neural circuits and previous work has suggested that dysregulated translation mediates certain forms of autism spectrum disorder (asd). here, we investigated the role of target of rapamycin complex 1 (torc1) in synaptic and dendritic development in vivo in the retinotectal system of xenopus laevis tadpoles. we found that torc1 signaling regulates dendritic growth and branching and that acute over-activation of torc1 by rheb overexp ...	2020	32996262
dna content contributes to nuclear size control in xenopus laevis.	cells adapt to drastic changes in genome quantity during evolution and cell division by adjusting the nuclear size to exert genomic functions. however, the mechanism by which dna content within the nucleus contributes to controlling the nuclear size remains unclear. here, we experimentally evaluated the effects of dna content by utilizing cell-free xenopus egg extracts and imaging of in vivo embryos. upon manipulation of dna content while maintaining cytoplasmic effects constant, both plateau si ...	2020	32997613
cross-talk between p2x and nmda receptors.	purinergic p2x receptors (p2x) are atp-gated ion channels widely expressed in the cns. while the direct contribution of p2x to synaptic transmission is uncertain, p2x reportedly affect n-methyl-d-aspartate receptor (nmdar) activity, which has given rise to competing theories on the role of p2x in the modulation of synapses. however, p2x have also been shown to participate in receptor cross-talk: an interaction where one receptor (e.g., p2x2) directly influences the activity of another (e.g., nic ...	2020	33003406
microtubule-dependent pushing forces contribute to long-distance aster movement and centration in xenopus laevis egg extracts.	during interphase of the eukaryotic cell cycle, the microtubule (mt) cytoskeleton serves as both a supportive scaffold for organelles and an arborized system of tracks for intracellular transport. at the onset of mitosis, the position of the astral mt network, specifically its center, determines the eventual location of the spindle apparatus and ultimately the cytokinetic furrow. positioning of the mt aster often results in its movement to the center of a cell, even in large blastomeres hundreds ...	2020	33026931
elucidating the framework for specification and determination of the embryonic retina.	how cell determination is regulated remains a major unsolved problem in developmental biology. the early embryonic rudiments of many tissues and organs are difficult or impossible to identify, isolate and study at the time when determination occurs. we have examined the commitment process leading to retina formation in xenopus laevis, where presumptive eye tissue can be identified and studied to assay its biological properties during the events leading up to determination. we find that for the r ...	2020	33031807
whole-brain calcium imaging in larval xenopus.	sensory systems detect environmental stimuli and transform them into electrical activity patterns interpretable by the central nervous system. en route to higher brain centers, the initial sensory input is successively transformed by interposed secondary processing centers. mapping the neuronal activity patterns at all of those stages is essential to understand sensory information processing. larval xenopus laevis is very well-suited for whole-brain imaging of neuronal activity. this is mainly d ...	2020	33037078
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
glutamate, d-(-)-2-amino-5-phosphonopentanoic acid, and n-methyl-d-aspartate do not directly modulate glycine receptors.	replication studies play an essential role in corroborating research findings and ensuring that subsequent experimental works are interpreted correctly. a previously published paper indicated that the neurotransmitter glutamate, along with the compounds n-methyl-d-aspartate (nmda) and d-(-)-2-amino-5-phosphonopentanoic acid (ap5), acts as positive allosteric modulators of inhibitory glycine receptors. the paper further suggested that this form of modulation would play a role in setting the spina ...	2020	33051383
scorpion toxin meunatxα-1 sensitizes primary nociceptors by selective modulation of voltage-gated sodium channels.	venoms are a rich source of highly specific toxins, which allow the identification of novel therapeutic targets. we have now applied high content screening (hcs) microscopy to identify toxins that modulate pain sensitization signaling in primary sensory neurons of rat and elucidated the underlying mechanism. a set of venoms and fractions thereof were analyzed for their ability to activate type ii protein kinase a (pka-ii) and extracellular signal-regulated kinases (erk1/2). we identified meunatx ...	2020	33051988
non-junctional role of cadherin3 in cell migration and contact inhibition of locomotion via domain-dependent, opposing regulation of rac1.	classical cadherins are well-known adhesion molecules responsible for physically connecting neighboring cells and signaling this cell-cell contact. recent studies have suggested novel signaling roles for "non-junctional" cadherins (njcads); however, the function of cadherin signaling independent of cell-cell contacts remains unknown. in this study, mesendodermal cells and tissues from gastrula stage xenopus laevis embryos demonstrate that deletion of extracellular domains of cadherin3 (cdh3; for ...	2020	33060598
derivation of proliferative islet1-positive cells during metamorphosis and wound response in xenopus.	in mammalian hearts, cardiomyocytes retain a transient capacity to proliferate and regenerate following injury before birth, whereas they lose proliferative capacity immediately after birth. it has also been known that cardiac progenitor cells including islet1-positive cells do not contribute to the cardiac repair and regeneration in mammals. in contrast, hearts of zebrafish, amphibians and reptiles maintain a regenerative ability throughout life. here, we analyzed proliferative capacity of card ...	2020	33070205
phosphoproteomic analysis of xenopus laevis reveals expression and phosphorylation of hypoxia-inducible pfkfb3 during dehydration.	xenopus laevis tolerate dehydration when their environments evaporate during summer months. protein phosphorylation has previously shown to regulate important adaptations in x. laevis, including the transition to anaerobic metabolism. we therefore performed phosphoproteomic analysis of x. laevis to further elucidate the cellular and metabolic responses to dehydration. phosphoproteins were enriched in cellular functions and pathways related to glycolysis/gluconeogenesis, the tca cycle, and protei ...	2020	33083755
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
rad21 is involved in corneal stroma development by regulating neural crest migration.	previously, we identified rad21r450c from a peripheral sclerocornea pedigree. injection of this rad21 variant mrna into xenopus laevis embryos disrupted the organization of corneal stroma fibrils. to understand the mechanisms of rad21-mediated corneal stroma defects, gene expression and chromosome conformation analysis were performed using cells from family members affected by peripheral sclerocornea. both gene expression and chromosome conformation of cell adhesion genes were affected in cells ...	2020	33096935
sclerostin inhibits wnt signaling through tandem interaction with two lrp6 ectodomains.	low-density lipoprotein receptor-related protein 6 (lrp6) is a coreceptor of the β-catenin-dependent wnt signaling pathway. the lrp6 ectodomain binds wnt proteins, as well as wnt inhibitors such as sclerostin (sost), which negatively regulates wnt signaling in osteocytes. although lrp6 ectodomain 1 (e1) is known to interact with sost, several unresolved questions remain, such as the reason why sost binds to lrp6 e1e2 with higher affinity than to the e1 domain alone. here, we present the crystal ...	2020	33097721
x-box-binding protein 1 is required for pancreatic development in xenopus laevis.	x-box-binding protein 1 (xbp1) is a protein containing the basic leucine zipper structure. it belongs to the camp-response element binding protein (creb)/activating transcription factor transcription factor family. as the main transcription factor, spliced xbp1 (xbp1s) participates in many physiological and pathological processes and plays an important role in embryonic development. previous studies showed that xbp1-knockout mice died because of pancreatic exocrine function deficiency, indicatin ...	2020	33098302
high affinity na+ transport by wheat hkt1;5 is blocked by k.	the wheat sodium transporters tmhkt1;5-a and tahkt1;5-d are encoded by genes underlying the major shoot na+ exclusion loci nax2 and kna1 from triticum monococcum (tm) and triticum aestivum (ta), respectively. in contrast to hkt2 transporters that have been shown to exhibit high affinity k+-dependent na+ transport, hkt1 proteins have, with one exception, only been shown to catalyze low affinity na+ transport and no k+ transport. here, using heterologous expression in xenopus laevis oocytes we unc ...	2020	33103046
observation of nucleic acids inside living human cells by in-cell nmr spectroscopy.	the intracellular environment is highly crowded with biomacromolecules such as proteins and nucleic acids. under such conditions, the structural and biophysical features of nucleic acids have been thought to be different from those in vitro. to obtain high-resolution structural information on nucleic acids in living cells, the in-cell nmr method is a unique tool. following the first in-cell nmr measurement of nucleic acids in 2009, several interesting insights were obtained using xenopus laevis ...	2020	33110737
nicotinic acetylcholine receptors in the synganglion of the tick ixodes ricinus: functional characterization using membrane microtransplantation.	nicotinic acetylcholine receptors are an important class of excitatory receptors in the central nervous system of arthropods. in the ticks ixodes ricinus, the functional and pharmacological properties of nicotinic receptors located in their neurons are still unknown. the objective of this study was to characterize the pharmacological properties of tick nicotinic receptors using membrane microtransplantation in xenopus laevis oocytes and two-electrodes voltage clamp method. the membranes microtra ...	2020	33120248
antimicrobial peptide induced-stress renders staphylococcus aureus susceptible to toxic nucleoside analogs.	cationic antimicrobial peptides (amps) are active immune effectors of multicellular organisms and are also considered as new antimicrobial drug candidates. one of the problems encountered when developing amps as drugs is the difficulty of reaching sufficient killing concentrations under physiological conditions. here, using pexiganan, a cationic peptide derived from a host defense peptide of the african clawed frog and the first amp developed into an antibacterial drug, we studied whether sub-le ...	2020	33133056
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
development of antimicrobial peptides from amphibians.	since the discovery of magainins from the skin secretions of the african toad xenopus laevis by michael zasloff in 1987, an increasing number of antimicrobial peptides (amps) has been identified in different anuran species and studied in detail [...].	2020	33158031
kunitz-type peptides from the sea anemone heteractis crispa demonstrate potassium channel blocking and anti-inflammatory activities.	the kunitz/bpti peptide family includes unique representatives demonstrating various biological activities. electrophysiological screening of peptides hcrg1 and hcrg2 from the sea anemone heteractis crispa on six kv1.x channel isoforms and insect shaker ir channel expressed in xenopus laevis oocytes revealed their potassium channels blocking activity. hcrg1 and hcrg2 appear to be the first kunitz-type peptides from sea anemones blocking kv1.3 with ic50 of 40.7 and 29.7 nm, respectively. in addit ...	2020	33158163
trim-away mediated knock down uncovers a new function for lbh during gastrulation of xenopus laevis.	we previously identified the protein lbh as necessary for cranial neural crest (cnc) cell migration in xenopus through the use of morpholinos. however, lbh is a maternally deposited protein and morpholinos achieve knockdowns through prevention of translation. in order to investigate the role of lbh in earlier embryonic events, we employed the new technique "trim-away" to degrade this maternally deposited protein. trim-away utilizes the e3 ubiquitin ligase trim21 to degrade proteins targeted with ...	2020	33159936
synthesis of glun2a-selective nmda receptor antagonists with an electron-rich aromatic b-ring.	glutamatergic n-methyl-d-aspartate (nmda) receptors are heterotetrameric ion channels that can be comprised of different subunits. glun2a subunit-containing nmda receptors are associated with diseases like anxiety, depression, and schizophrenia. however, the exact contribution of these nmda receptor subtypes is still unclear. to understand better the role of the glun2a-containing receptors, novel ligands were designed. in co-crystallization with the isolated binding site, tcn-201 (1) and analogs ...	2020	33162207
epigenetic regulation of replication origin assembly: a role for histone h1 and chromatin remodeling factors.	during early embryonic development in several metazoans, accurate dna replication is ensured by high number of replication origins. this guarantees rapid genome duplication coordinated with fast cell divisions. in xenopus laevis embryos this program switches to one with a lower number of origins at a developmental stage known as mid-blastula transition (mbt) when cell cycle length increases and gene transcription starts. consistent with this regulation, somatic nuclei replicate poorly when trans ...	2020	33165968
mechanisms activating latent functions of pip aquaporin water channels via the interaction between pip1 and pip2 proteins.	plant plasma-membrane type pip aquaporins are classified into two groups, pip1s and pip2s. in this study, we focused on hvpip1; 2, a pip1 in barley (hordeum vulgare), to dissect the molecular mechanisms that evoke hvpip1-mediated water transport. no hvpip1; 2 protein was localized to the plasma membrane when expressed alone in xenopus laevis oocytes. in contrast, a chimeric hvpip1; 2 protein (hvpip1; 2_24nc), in which the n- and c-terminal regions were replaced with the corresponding regions fro ...	2020	33169164
ecotoxicological assessment of commercial boron nitride nanotubes toward xenopus laevis tadpoles and host-associated gut microbiota.	despite the growing interest for boron nitride nanotubes (bnnt) due to their unique properties, data on the evaluation of the environmental risk potential of this emerging engineered nanomaterial are currently lacking. therefore, the ecotoxicity of a commercial form of bnnt (containing tubes, hexagonal-boron nitride, and boron) was assessed in vivo toward larvae of the amphibian xenopus laevis. following the exposure, multiple endpoints were measured in the tadpoles as well as in bacterial commu ...	2020	33171057
effects of copper on the neuromasts of xenopus laevis.	fish and aquatic amphibians possess neuromasts on the surface of their body that constitute the lateral line, a sensory system used to detect water displacement. copper is known to inactivate the neuromast organs of this system. copper-induced neuromast loss in african clawed frogs, xenopus laevis, was examined by exposing nieuwkoop-faber stage 54-55 larvae to copper concentrations of 0, 100, 200, 300, and 400 µg/l for 96 h, followed by an examination of neuromast counts, staining intensity, and ...	2020	33180147
surface contraction waves or cell proliferation waves in the presumptive neurectoderm during amphibian gastrulation: mexican axolotl versus african clawed frog.	this essay represents a critical analysis of the literary data on various types of waves occurring in the amphibian embryos during gastrulation. a surface contraction wave travels through the presumptive neurectoderm during mexican axolotl gastrulation. this wave coincides temporally and spatially with involution of the inducing chordomesoderm and with the prospective neural plate. by contrast, there is no similar surface contraction wave during african clawed frog gastrulation. however, the cla ...	2020	33181236