Publications

in vivo modulation and quantification of micrornas during axolotl tail regeneration.	the ability to regenerate diseased, injured, or missing complex tissue is widespread throughout lower vertebrates and invertebrates; however, our knowledge of the molecular mechanisms that regulate this amazing ability is still in its infancy. many recent papers have shown important roles for micrornas in regulating regeneration in a number of species. the ability to detect and quantify mirna expression fluctuations at a single cell level in vivo in different cell types during processes like reg ...	2015	25740485
thyroxine-induced metamorphosis in the axolotl (ambystoma mexicanum).	the axolotl (ambystoma mexicanum) has remained an important model for regeneration and developmental biology for over a century. although axolotls in captive-bred colonies usually exist in an aquatic form, they retain the ability to undergo metamorphosis following exposure to thyroid hormone. here we present a robust method for inducing metamorphosis in adult axolotls that results in high survivability and produces terrestrial animals that can be maintained in long-term captivity.	2015	25740483
high-efficiency electroporation of the spinal cord in larval axolotl.	axolotls are well known for their remarkable ability to regenerate complex body parts and structures throughout life, including the entire limb and tail. particularly fascinating is their ability to regenerate a fully functional spinal cord after losing the tail. electroporation of dna plasmids or morpholinos is a valuable tool to gain mechanistic insight into the cellular and molecular basis of regeneration. it provides among other advantages a simple and fast method to test gene function in a ...	2015	25740481
studying newt brain regeneration following subtype specific neuronal ablation.	the realization that neuronal injury does not result in permanent functional or cellular loss in all vertebrates has fascinated regenerative biologists. neuronal regeneration occurs in a subset of species, including lizards, teleost fish, axolotls, and newts. one tool for studying neuronal regeneration in the adult brain is intraventricular injection of selective neuronal toxins, which leads to loss of subpopulations of neurons. to trace cells involved in the regeneration process, plasmids encod ...	2015	25740479
housing and maintenance of ambystoma mexicanum, the mexican axolotl.	the aim of this paper is to assemble a significant amount of information on ambystoma mexicanum, the axolotl salamander, to assist in the basic knowledge needed to raise, breed, and study most aspects of axolotl biology. it is important to understand the basic biology of the axolotl in order to make informed decisions on their proper care and use in experiments. therefore, we will provide necessary information to the non-herpetologist that will assist in their study of this unique and fascinatin ...	2015	25740475
[on the classification of the cleavage patterns in amphibian embryos].	this paper presents a brief survey and preliminary classification of embryonic cleavage patterns in the class amphibia. we use published data on 41 anuran and 22 urodele species concerning the character of the third cleavage furrow (latitudinal or longitudinal) and the stage of transition from synchronous to asynchronous blastomere divisions in the animal hemisphere (4-8-celled stage, 8-16-celled stage or later). based on this, four patterns of amphibian embryonic cleavage are recognized, and an ...	2015	25720261
long-duration muscle dedifferentiation during limb regeneration in axolotls.	although still debated, limb regeneration in salamanders is thought to depend on the dedifferentiation of remnant tissue occurring early after amputation and generating the progenitor cells that initiate regeneration. this dedifferentiation has been demonstrated previously by showing the fragmentation of muscle fibers into mononucleated cells and by revealing the contribution of mature muscle fibers to the regenerates by using lineage-tracing studies. here, we provide additional evidence of dedi ...	2015	25671422
identification of reference genes and validation for gene expression studies in diverse axolotl (ambystoma mexicanum) tissues.	for the precise quantitative rt-pcr normalization a set of valid reference genes is obligatory. moreover have to be taken into concern the experimental conditions as they bias the regulation of reference genes. up till now, no reference targets have been described for the axolotl (ambystoma mexicanum). in a search in the public database salsite for genetic information of the axolotl we identified fourteen presumptive reference genes, eleven of which were further tested for their gene expression ...	2015	25637570
talen-mediated gene editing of the thrombospondin-1 locus in axolotl.	loss-of-function genetics provides strong evidence for a gene's function in a wild-type context. in many model systems, this approach has been invaluable for discovering the function of genes in diverse biological processes. axolotls are urodele amphibians (salamanders) with astonishing regenerative abilities, capable of regenerating entire limbs, portions of the tail (including spinal cord), heart, and brain into adulthood. with their relatively short generation time among salamanders, they off ...	2015	27499866
homodimeric anoctamin-1, but not homodimeric anoctamin-6, is activated by calcium increases mediated by the p2y1 and p2x7 receptors.	the p2x7 receptor (p2x7r) is a ligand-gated ion channel that conducts na(+), k(+), and ca(2+) when activated by extracellular atp. in various cell types, such as secretory epithelia, the p2x7r is co-expressed with ca(2+)-dependent cl(-) channels of the tmem16/anoctamin family. here, we studied whether the p2x7r and tmem16a/anoctamin-1 (ano1) or tmem16f/anoctamin-6 (ano6) interact functionally and physically, using oocytes of xenopus laevis and ambystoma mexicanum (axolotl) for heterologous expre ...	2015	25592660
[radioautographic and electron microscopic research on the structure and dynamic proliferative activity of muscle satellite cells during limb muscle transplantation in axolotls].		2015	3231405
histone deacetylases are required for amphibian tail and limb regeneration but not development.	amphibians such as xenopus laevis and ambystoma mexicanum are capable of whole structure regeneration. however, transcriptional control over these events is not well understood. here, we investigate the role of histone deacetylase (hdac) enzymes in regeneration using hdac inhibitors. the class i/ii hdac inhibitor valproic acid (vpa) inhibits tail regeneration in embryos of the anuran amphibian xenopus laevis, confirming a recent report by others (tseng et al., 2011). this inhibition correlates w ...	2015	22947425
[specific growth rate and the rate of energy metabolism in the ontogenesis of axolotl, ambystoma mexicanum (amphibia: ambystomatidae)].	concordant changes in the rate of energy metabolism and specific growth rate of axolotls have been revealed. several periods of ontogeny are distinguished, which differ in the ratio of energy metabolism to body weight and, therefore, are described by different allometric equations. it is suggested that the specific growth rate of an animal determines the type of dependence of energy metabolism on body weight.	2016	14994475
drug-induced and genetic hypermelanism: effects on pigment cell differentiation.	allopurinol, a drug that inhibits the enzyme xanthine dehydrogenase (xdh), is known to cause hypermelanism in the axolotl. the hypermelanistic condition that results from allopurinol treatment is similar in most respects to the phenotype that results from the action of the melanoid (m) gene in axolotls. on the basis of structural and biochemical studies, it now seems clear that genetic and drug-induced hypermelanism are the same in the following ways. 1) both types of melanism result in the prod ...	2016	2771877
immunocytochemical characterisation of ensheathing glia in the olfactory and vomeronasal systems of ambystoma mexicanum (caudata: ambystomatidae).	the olfactory and vomeronasal systems of vertebrates are characterised by neurogenesis occurring throughout life. the regenerative ability of olfactory receptor neurons relies on specific glial cells, the olfactory and vomeronasal axon-surrounding cells. numerous studies have examined mammalian olfactory ensheathing cells which are considered potential candidates for spinal cord injury repair using cell-based therapy. with regard to non-mammalian vertebrates, limited information is available on ...	2016	25433448
a novel role for sall4 during scar-free wound healing in axolotl.	the human response to serious cutaneous damage is limited to relatively primitive wound healing, whereby collagenous scar tissue fills the wound bed. scars assure structural integrity at the expense of functional regeneration. in contrast, axolotls have the remarkable capacity to functionally regenerate full thickness wounds. here, we identified a novel role for sall4 in regulating collagen transcription after injury that is essential for perfect skin regeneration in axolotl. furthermore, we ide ...	2016	28955504
cooperative inputs of bmp and fgf signaling induce tail regeneration in urodele amphibians.	urodele amphibians have remarkable organ regeneration ability. they can regenerate not only limbs but also a tail throughout their life. it has been demonstrated that the regeneration of some organs are governed by the presence of neural tissues. for instance, limb regeneration cannot be induced without nerves. thus, identifying the nerve factors has been the primary focus in amphibian organ regeneration research. recently, substitute molecules for nerves in limb regeneration, bmp and fgfs, were ...	2016	26703427
myocardial plasticity: cardiac development, regeneration and disease.	the adult mammalian heart is unable to recover from myocardial cell loss due to cardiac ischemia and infarction because terminally differentiated cardiomyocytes proliferate at a low rate. however, cardiomyocytes in other vertebrate animal models such as zebrafish, axolotls, newts and mammalian mouse neonates are capable of de-differentiating in order to promote cardiomyocyte proliferation and subsequent cardiac regeneration after injury. although de-differentiation may occur in adult mammalian c ...	2016	27498024
activation of smad2 but not smad3 is required to mediate tgf-β signaling during axolotl limb regeneration.	axolotls are unique among vertebrates in their ability to regenerate tissues, such as limbs, tail and skin. the axolotl limb is the most studied regenerating structure. the process is well characterized morphologically; however, it is not well understood at the molecular level. we demonstrate that tgf-β1 is highly upregulated during regeneration and that tgf-β signaling is necessary for the regenerative process. we show that the basement membrane is not prematurely formed in animals treated with ...	2016	27549395
histological image data of limb skeletal tissue from larval and adult ambystoma mexicanum.	the data presented in this article are related to the article entitled "cartilage and bone cells do not participate in skeletal regeneration in ambystoma mexicanum limbs" [1]. here we present image data of the post-embryonic development of the forelimb skeletal tissue of ambystoma mexicanum. histological staining was performed on sections from the intact limbs of young (6.5 cm) and old (25 cm) animals, and on dissected skeletal tissues (cartilage, bone, and periosteum) from these animals.	2016	27547798
liver histological changes and lipid peroxidation in the amphibian ambystoma mexicanum induced by sediment elutriates from the lake xochimilco.	lacustrine sediments accumulate pollutants that input from the lake watershed and can be released to the water column by sediment resuspension; thus, pollutants can change their bioavailability and exert adverse effects to aquatic biota. shallow-urban lakes are particularly susceptible to receive pollutants from urban discharges and sediment resuspension. lake xochimilco, in mexico city, an urban-shallow lake, faces multiple problems: urban sprawl, overexploitation of aquifers, drying of springs ...	2016	27521947
genome-wide analysis reveals conserved transcriptional responses downstream of resting potential change in xenopus embryos, axolotl regeneration, and human mesenchymal cell differentiation.	endogenous bioelectric signaling via changes in cellular resting potential (v mem) is a key regulator of patterning during regeneration and embryogenesis in numerous model systems. depolarization of v mem has been functionally implicated in dedifferentiation, tumorigenesis, anatomical re-specification, and appendage regeneration. however, no unbiased analyses have been performed to understand genome-wide transcriptional responses to v mem change in vivo. moreover, it is unknown which genes or ge ...	2016	27499876
limb regeneration.	limb regeneration is observed in certain members of the animal phyla. some animals keep this ability during their entire life while others lose it at some time during development. how do animals regenerate limbs? is it possible to find unifying, conserved mechanisms of limb regeneration or have different species evolved distinct means of replacing a lost limb? how is limb regeneration similar or different to limb development? studies on many organisms, including echinoderms, arthropods, and chor ...	2016	24009038
adult axolotls can regenerate original neuronal diversity in response to brain injury.	the axolotl can regenerate multiple organs, including the brain. it remains, however, unclear whether neuronal diversity, intricate tissue architecture, and axonal connectivity can be regenerated; yet, this is critical for recovery of function and a central aim of cell replacement strategies in the mammalian central nervous system. here, we demonstrate that, upon mechanical injury to the adult pallium, axolotls can regenerate several of the populations of neurons present before injury. notably, ...	2016	27156560
expression analysis of baf60c during heart regeneration in axolotls and neonatal mice.	some organisms, such as zebrafish, urodele amphibians, and newborn mice, have a capacity for heart regeneration following injury. however, adult mammals fail to regenerate their hearts. to know why newborn mice can regenerate their hearts, we focused on epigenetic factors, which are involved in cell differentiation in many tissues. baf60c (brg1/brm-associated factor 60c), a component of atp-dependent chromatin-remodeling complexes, has an essential role for cardiomyocyte differentiation at the e ...	2016	27125315
fgf8 and shh substitute for anterior-posterior tissue interactions to induce limb regeneration.	in salamanders, grafting of a left limb blastema onto a right limb stump yields regeneration of three limbs, the normal limb and two 'supernumerary' limbs. this experiment and other research have shown that the juxtaposition of anterior and posterior limb tissue plus innervation are necessary and sufficient to induce complete limb regeneration in salamanders. however, the cellular and molecular basis of the requirement for anterior-posterior tissue interactions were unknown. here we have clarifi ...	2016	27120163
the role of stem cells in limb regeneration.	limb regeneration is a complex yet fascinating process observed to some extent in many animal species, though seen in its entirety in urodele amphibians. accomplished by formation of a morphologically uniform intermediate, the blastema, scientists have long attempted to define the cellular constituents that enable regrowth of a functional appendage. today, we know that the blastema consists of a variety of multipotent progenitor cells originating from a variety of tissues, and which contribute t ...	2016	27008101
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 ...	2016	26934886
marcks-like protein is an initiating molecule in axolotl appendage regeneration.	identifying key molecules that launch regeneration has been a long-sought goal. multiple regenerative animals show an initial wound-associated proliferative response that transits into sustained proliferation if a considerable portion of the body part has been removed. in the axolotl, appendage amputation initiates a round of wound-associated cell cycle induction followed by continued proliferation that is dependent on nerve-derived signals. a wound-associated molecule that triggers the initial ...	2016	26934225
proteinaceous pheromone homologs identified from the cloacal gland transcriptome of a male axolotl, ambystoma mexicanum.	pheromones play an important role in modifying vertebrate behavior, especially during courtship and mating. courtship behavior in urodele amphibians often includes female exposure to secretions from the cloacal gland, as well as other scent glands. the first vertebrate proteinaceous pheromone discovered, the decapeptide sodefrin, is a female attracting pheromone secreted by the cloacal gland of male cynops pyrrhogaster. other proteinaceous pheromones in salamanders have been shown to elicit resp ...	2016	26885665
courtship pheromone use in a model urodele, the mexican axolotl (ambystoma mexicanum).	sex pheromones have been shown to constitute a crucial aspect of salamander reproduction. until now, courtship pheromones of salamandridae and plethodontidae have been intensively studied, but information on chemical communication in other urodelan families is essentially lacking. the axolotl (ambystoma mexicanum, ambystomatidae) has a courtship display that suggests a key role for chemical communication in the orchestration of its sexual behavior, but no sex pheromones have yet been characteriz ...	2016	26842386
localization of amylin-like immunoreactivity in melanocyte-stimulating hormone-containing cells of the pars intermedia but not those of the pars distalis in the axolotl (ambystoma mexicanum) pituitary.	immunohistochemical techniques were employed to investigate the distribution of amylin-like immunoreactivity in the axolotl (ambystoma mexicanum) pituitary. amylin-immunoreactive cells were observed in the pars intermedia, and these cells were found to be immunoreactive for α-melanocyte-stimulating hormone (αmsh) as well. in contrast, αmsh-immunoreactive cells in the pars distalis were immuno-negaitive for amylin. these light microscopic findings were confirmed by immunoelectron microscopy. amyl ...	2016	26797189
fgf and bmp derived from dorsal root ganglia regulate blastema induction in limb regeneration in ambystoma mexicanum.	urodele amphibians have a remarkable organ regeneration ability that is regulated by neural inputs. the identification of these neural inputs has been a challenge. recently, fibroblast growth factor (fgf) and bone morphogenic protein (bmp) were shown to substitute for nerve functions in limb and tail regeneration in urodele amphibians. however, direct evidence of fgf and bmp being secreted from nerve endings and regulating regeneration has not yet been shown. thus, it remained uncertain whether ...	2016	27432514
a concise review of common animal models for the study of limb regeneration.	correct selection of an appropriate animal mode to closely mimic human extremity diseases or to exhibit desirable phenotypes of limb regeneration is the first critical step for all scientists in biomedical and regenerative researches. the commonly-used animals in limb regeneration and repairing studies, such as axolotl, mice, and rats, are discussed in the review and other models including cockroaches, dogs, and horses are also mentioned. the review weighs the general advantages, disadvantages, ...	2016	27391218
a conserved microrna regulatory circuit is differentially controlled during limb/appendage regeneration.	although regenerative capacity is evident throughout the animal kingdom, it is not equally distributed throughout evolution. for instance, complex limb/appendage regeneration is muted in mammals but enhanced in amphibians and teleosts. the defining characteristic of limb/appendage regenerative systems is the formation of a dedifferentiated tissue, termed blastema, which serves as the progenitor reservoir for regenerating tissues. in order to identify a genetic signature that accompanies blastema ...	2016	27355827
could we also be regenerative superheroes, like salamanders?	development of methods to reawaken the semi-dormant regenerative potential that lies within adult human tissues would hold promise for the restoration of diseased or damaged organs and tissues. while most of the regeneration potential is suppressed in many vertebrates, including humans, during adult life, urodele amphibians (salamanders) retain their regenerative ability throughout adulthood. studies in newts and axolotls, two salamander models, have provided significant knowledge about adult li ...	2016	27338874
neuregulin-1 signaling is essential for nerve-dependent axolotl limb regeneration.	the mexican axolotl (ambystoma mexicanum) is capable of fully regenerating amputated limbs, but denervation of the limb inhibits the formation of the post-injury proliferative mass called the blastema. the molecular basis behind this phenomenon remains poorly understood, but previous studies have suggested that nerves support regeneration via the secretion of essential growth-promoting factors. an essential nerve-derived factor must be found in the blastema, capable of rescuing regeneration in d ...	2016	27317805
cartilage and bone cells do not participate in skeletal regeneration in ambystoma mexicanum limbs.	the mexican axolotl is one of the few tetrapod species that is capable of regenerating complete skeletal elements in injured adult limbs. whether the skeleton (bone and cartilage) plays a role in the patterning and contribution to the skeletal regenerate is currently unresolved. we tested the induction of pattern formation, the effect on cell proliferation, and contributions of skeletal tissues (cartilage, bone, and periosteum) to the regenerating axolotl limb. we found that bone tissue grafts f ...	2016	27316294
tissue- and time-directed electroporation of cas9 protein-grna complexes in vivo yields efficient multigene knockout for studying gene function in regeneration.	a rapid method for temporally and spatially controlled crispr-mediated gene knockout in vertebrates will be an important tool to screen for genes involved in complex biological phenomena like regeneration. here we show that in vivo injection of cas9 protein-guide rna (grna) complexes into the spinal cord lumen of the axolotl and subsequent electroporation leads to comprehensive knockout of sox2 gene expression in sox2+ neural stem cells with corresponding functional phenotypes from the gene knoc ...	2016	29302334
accessories to limb regeneration.	in a recent issue of nature, nacu et al. (2016) identified fgf and hh ligands as interacting molecular influences that are necessary and sufficient to induce the formation of supernumerary limbs from blastemal tissue in axolotl salamanders.	2016	27219058
oral-facial tissue reconstruction in the regenerative axolotl.	absence of large amounts of orofacial tissues caused by cancerous resections, congenital defects, or trauma results in sequelae such as dysphagia and noticeable scars. oral-neck tissue regeneration was studied in the axolotl (regenerative amphibian) following a 2.5-mm punch biopsy that simultaneously removed skin, connective tissue, muscle, and cartilage in the tongue and intermandibular region. the untreated wound was studied macroscopically and histologically at 17 different time points rangin ...	2016	28121390
joint encoding of object motion and motion direction in the salamander retina.	the processing of motion in visual scenes is important for detecting and tracking moving objects as well as for monitoring self-motion through the induced optic flow. specialized neural circuits have been identified in the vertebrate retina for detecting motion direction or for distinguishing between object motion and self-motion, although little is known about how information about these distinct features of visual motion is combined. the salamander retina, which is a widely used model system f ...	2016	27903729
accelerated cell divisions drive the outgrowth of the regenerating spinal cord in axolotls.	axolotls are unique in their ability to regenerate the spinal cord. however, the mechanisms that underlie this phenomenon remain poorly understood. previously, we showed that regenerating stem cells in the axolotl spinal cord revert to a molecular state resembling embryonic neuroepithelial cells and functionally acquire rapid proliferative divisions (rodrigo albors et al., 2015). here, we refine the analysis of cell proliferation in space and time and identify a high-proliferation zone in the re ...	2016	27885987
live imaging of axolotl digit regeneration reveals spatiotemporal choreography of diverse connective tissue progenitor pools.	connective tissues-skeleton, dermis, pericytes, fascia-are a key cell source for regenerating the patterned skeleton during axolotl appendage regeneration. this complexity has made it difficult to identify the cells that regenerate skeletal tissue. inability to identify these cells has impeded a mechanistic understanding of blastema formation. by tracing cells during digit tip regeneration using brainbow transgenic axolotls, we show that cells from each connective tissue compartment have distinc ...	2016	27840105
multiplicity of buc copies in atlantic salmon contrasts with loss of the germ cell determinant in primates, rodents and axolotl.	the primordial germ cells (pgcs) giving rise to gametes are determined by two different mechanisms in vertebrates. while the germ cell fate in mammals and salamanders is induced by zygotic signals, maternally delivered germ cell determinants specify the pgcs in birds, frogs and teleost fish. assembly of the germ plasm in the oocyte is organized by the single buc in zebrafish, named velo1 in xenopus, and by oskar in drosophila. secondary loss of oskar in several insect lineages coincides with cha ...	2016	27784263
a histological atlas of the tissues and organs of neotenic and metamorphosed axolotl.	axolotl (ambystoma mexicanum) has been emerging as a promising model in stem cell and regeneration researches due to its exceptional regenerative capacity. although it represents lifelong lasting neoteny, induction to metamorphosis with thyroid hormones (ths) treatment advances the utilization of axolotl in various studies. it has been reported that amphibians undergo anatomical and histological remodeling during metamorphosis and this transformation is crucial for adaptation to terrestrial cond ...	2016	27436816
beryllium nitrate inhibits fibroblast migration to disrupt epimorphic regeneration.	epimorphic regeneration proceeds with or without formation of a blastema, as observed for the limb and skin, respectively. inhibition of epimorphic regeneration provides a means to interrogate the cellular and molecular mechanisms that regulate it. in this study, we show that exposing amputated limbs to beryllium nitrate disrupts blastema formation and causes severe patterning defects in limb regeneration. in contrast, exposing full-thickness skin wounds to beryllium only causes a delay in skin ...	2016	27578793
homology of the cranial vault in birds: new insights based on embryonic fate-mapping and character analysis.	bones of the cranial vault appear to be highly conserved among tetrapod vertebrates. moreover, bones identified with the same name are assumed to be evolutionarily homologous. however, recent developmental studies reveal a key difference in the embryonic origin of cranial vault bones between representatives of two amniote lineages, mammals and birds, thereby challenging this view. in the mouse, the frontal is derived from cranial neural crest (cnc) but the parietal is derived from mesoderm, plac ...	2016	27853617
evolution of the head-trunk interface in tetrapod vertebrates.	vertebrate neck musculature spans the transition zone between head and trunk. the extent to which the cucullaris muscle is a cranial muscle allied with the gill levators of anamniotes or is instead a trunk muscle is an ongoing debate. novel computed tomography datasets reveal broad conservation of the cucullaris in gnathostomes, including coelacanth and caecilian, two sarcopterygians previously thought to lack it. in chicken, lateral plate mesoderm (lpm) adjacent to occipital somites is a recent ...	2016	27090084
the evolution of basal progenitors in the developing non-mammalian brain.	the amplification of distinct neural stem/progenitor cell subtypes during embryogenesis is essential for the intricate brain structures present in various vertebrate species. for example, in both mammals and birds, proliferative neuronal progenitors transiently appear on the basal side of the ventricular zone of the telencephalon (basal progenitors), where they contribute to the enlargement of the neocortex and its homologous structures. in placental mammals, this proliferative cell population c ...	2016	26732839
[localization of glycogen in the axolotl egg before and during the first division].		2016	5063586
the electrical properties of the ectoderm in the amphibian embryo during induction and early development of the nervous system.	1. the electrical properties of ectodermal cells have been studied in embryos of the axolotl ambystoma mexicanum between gastrulation and the closure of the neural tube.2. at the time of neural induction by the underlying mesoderm the mean membrane potential recorded in ectoderm cells was -30 mv (+/- 1.5 mv s.e. of mean) and in presumptive neural cells -27 mv (+/- 1.6 mv s.e. of mean).3. at late neural fold stages, when specification of the neuroectoderm is complete, the membrane potential in pr ...	2016	4778140
the first cleavage of the amphibian egg. an electron microscope study of the onset of cytokinesis in the egg of ambystoma mexicanum.		2016	4914286
evaluation of the anesthetic effects of ms222 in the adult mexican axolotl (ambystoma mexicanum).	the mexican axolotl (ambystoma mexicanum) is a unique research model in several fields of medicine, where surgical and invasive procedures may be required. as yet, little is known about the efficacy of ms222 (tricaine methanesulfonate), which is the most commonly used anesthetic agent in amphibians. the main objectives of this study were to evaluate the anesthetic effects and physiological changes in adult axolotls following a 20-minute immersion bath, containing progressive ms222 concentrations ...	2016	30050832
[study of charge variation of neurosecretory perikaryons during induced metamorphosis in ambystoma mexicanum (shaw)].		2016	5148651
[contributions to the study of the morphology of the neurosecretory system in ambystoma mexicanum and its larva].		2016	5509951
biology's beloved amphibian - the axolotl - is racing towards extinction.		2017	32080554
mccrearamycins a-d, geldanamycin-derived cyclopentenone macrolactams from an eastern kentucky abandoned coal mine microbe.	four cyclopentenone-containing ansamycin polyketides (mccrearamycins a-d), and six new geldanamycins (gdms b-g, including new linear and mycothiol conjugates), were characterized as metabolites of streptomyces sp. ad-23-14 isolated from the rock creek underground coal mine acid drainage site. biomimetic chemical conversion studies using both simple synthetic models and gdm d confirmed that the mccrearamycin cyclopentenone derives from benzilic acid rearrangement of 19-hydroxy gdm, and thereby pr ...	2017	28140487
identification of mutant genes and introgressed tiger salamander dna in the laboratory axolotl, ambystoma mexicanum.	the molecular genetic toolkit of the mexican axolotl, a classic model organism, has matured to the point where it is now possible to identify genes for mutant phenotypes. we used a positional cloning-candidate gene approach to identify molecular bases for two historic axolotl pigment phenotypes: white and albino. white (d/d) mutants have defects in pigment cell morphogenesis and differentiation, whereas albino (a/a) mutants lack melanin. we identified in white mutants a transcriptional defect in ...	2017	28127056
reading and editing the pleurodeles waltl genome reveals novel features of tetrapod regeneration.	salamanders exhibit an extraordinary ability among vertebrates to regenerate complex body parts. however, scarce genomic resources have limited our understanding of regeneration in adult salamanders. here, we present the ~20 gb genome and transcriptome of the iberian ribbed newt pleurodeles waltl, a tractable species suitable for laboratory research. we find that embryonic stem cell-specific mirnas mir-93b and mir-427/430/302, as well as harbinger dna transposons carrying the myb-like proto-onco ...	2017	29273779
heart regeneration in adult xenopus tropicalis after apical resection.	myocardium regeneration in adult mammals is very limited, but has enormous therapeutic potentials. however, we are far from complete understanding the cellular and molecular mechanisms by which heart tissue can regenerate. the full functional ability of amphibians to regenerate makes them powerful animal models for elucidating how damaged mature organs are naturally reconstituted in an adult organism. like other amphibians, such as newts and axolotls, adult xenopus displays high regenerative cap ...	2017	29255592
regulation of regeneration by heparan sulfate proteoglycans in the extracellular matrix.	just as the building of a house requires a blueprint, the rebuilding of lost or damaged body parts through regeneration requires a set of instructions for the assembly of the various tissues into the right places. much progress has been made in understanding how to control the differentiation of different cell types to provide the building blocks for regeneration, such as bone, muscle, blood vessels and nerves/schwann cells. these are the cells that follow the blueprint (the pattern-following ce ...	2017	29242821
the axolotl limb regeneration model as a discovery tool for engineering the stem cell niche.	recent advances in genomics and gene editing have expanded the range of model organisms to include those with interesting biological capabilities such as regeneration. among these are the classic models of regeneration biology, the salamander. although stimulating endogenous regeneration in humans likely is many years away, with advances in stem cell biology and biomedical engineering (e.g. bio-inspired materials), it is evident that there is great potential to enhance regenerative outcomes by a ...	2017	29230380
convergent evolutionary reduction of atrial septation in lungless salamanders.	nearly two thirds of the approximately 700 species of living salamanders are lungless. these species respire entirely through the skin and buccopharyngeal mucosa. lung loss dramatically impacts the configuration of the circulatory system but the effects of evolutionary lung loss on cardiac morphology have long been controversial. for example, there is presumably little need for an atrial septum in lungless salamanders due to the absence of pulmonary veins and the presence of a single source of m ...	2017	27558020
re-epithelialization of large wound in paedomorphic and metamorphic axolotls.	axolotls (ambystoma mexicanum) may heal their skin wounds scar-free in both paedomorphs and metamorphs. in previous studies on small punch skin wounds, rapid re-epithelialisation was noted in these two axolotl morphs. however, large wound size in mammals may affect wound healing. in this study, large circumferential full thickness excision wounds on the hind limbs were created on juvenile paedomorphic and metamorphic axolotls. the results showed re-epithelialisation was more quickly initiated in ...	2017	27859516
detailed tail proteomic analysis of axolotl (ambystoma mexicanum) using an mrna-seq reference database.	salamander axolotl has been emerging as an important model for stem cell research due to its powerful regenerative capacity. several advantages, such as the high capability of advanced tissue, organ, and appendages regeneration, promote axolotl as an ideal model system to extend our current understanding on the mechanisms of regeneration. acknowledging the common molecular pathways between amphibians and mammals, there is a great potential to translate the messages from axolotl research to mamma ...	2017	27896924
conserved and novel functions of programmed cellular senescence during vertebrate development.	cellular senescence, a form of stable cell cycle arrest that is traditionally associated with tumour suppression, has been recently found to occur during mammalian development. here, we show that cell senescence is an intrinsic part of the developmental programme in amphibians. programmed senescence occurs in specific structures during defined time windows during amphibian development. it contributes to the physiological degeneration of the amphibian pronephros and to the development of the ceme ...	2017	27888193
a tissue-mapped axolotl de novo transcriptome enables identification of limb regeneration factors.	mammals have extremely limited regenerative capabilities; however, axolotls are profoundly regenerative and can replace entire limbs. the mechanisms underlying limb regeneration remain poorly understood, partly because the enormous and incompletely sequenced genomes of axolotls have hindered the study of genes facilitating regeneration. we assembled and annotated a de novo transcriptome using rna-sequencing profiles for a broad spectrum of tissues that is estimated to have near-complete sequence ...	2017	28099853
amphibase: a new genomic resource for non-model amphibian species.	more than five thousand genes annotated in the recently published xenopus laevis and xenopus tropicalis genomes do not have a candidate orthologous counterpart in other vertebrate species. to determine whether these sequences represent genuine amphibian-specific genes or annotation errors, it is necessary to analyze them alongside sequences from other amphibian species. however, due to large genome sizes and an abundance of repeat sequences, there are limited numbers of gene sequences available ...	2017	28095648
retinoic acid receptor regulation of epimorphic and homeostatic regeneration in the axolotl.	salamanders are capable of regenerating amputated limbs by generating a mass of lineage-restricted cells called a blastema. blastemas only generate structures distal to their origin unless treated with retinoic acid (ra), which results in proximodistal (pd) limb duplications. little is known about the transcriptional network that regulates pd duplication. in this study, we target specific retinoic acid receptors (rars) to either pd duplicate (ra treatment or rarγ agonist) or truncate (rarβ antag ...	2017	28087637
regulation of injury-induced ovarian regeneration by activation of oogonial stem cells.	some animals have the ability to generate large numbers of oocytes throughout life. this raises the question whether persistent adult germline stem cell populations drive continuous oogenesis and whether they are capable of mounting a regenerative response after injury. here we demonstrate the presence of adult oogonial stem cells (oscs) in the adult axolotl salamander ovary and show that ovarian injury induces osc activation and functional regeneration of the ovaries to reproductive capability. ...	2017	28028909
the posterior neural plate in axolotl gives rise to neural tube or turns anteriorly to form somites of the tail and posterior trunk.	classical grafting experiments in the mexican axolotl had shown that the posterior neural plate of the neurula is no specified neuroectoderm but gives rise to somites of the tail and posterior trunk. the bipotentiality of this region with neuromesodermal progenitor cell populations was revealed more recently also in zebrafish, chick, and mouse. we reinvestigated the potency of the posterior plate in axolotl using grafts from transgenic embryos, immunohistochemistry, and in situ hybridization. th ...	2017	28017643
mechanisms of vertebrate germ cell determination.	two unique characteristics of the germ line are the ability to persist from generation to generation and to retain full developmental potential while differentiating into gametes. how the germ line is specified that allows it to retain these characteristics within the context of a developing embryo remains unknown and is one focus of current research. germ cell specification proceeds through one of two basic mechanisms: cell autonomous or inductive. here, we discuss how germ plasm driven germ ce ...	2017	27975276
biology's beloved amphibian - the axolotl - is racing towards extinction.		2017	29144487
transcriptome dynamics along axolotl regenerative development are consistent with an extensive reduction in gene expression heterogeneity in dedifferentiated cells.	although in recent years the study of gene expression variation in the absence of genetic or environmental cues or gene expression heterogeneity has intensified considerably, many basic and applied biological fields still remain unaware of how useful the study of gene expression heterogeneity patterns might be for the characterization of biological systems and/or processes. largely based on the modulator effect chromatin compaction has for gene expression heterogeneity and the extensive changes ...	2017	29134148
identification of regenerative roadblocks via repeat deployment of limb regeneration in axolotls.	axolotl salamanders are powerful models for understanding how regeneration of complex body parts can be achieved, whereas mammals are severely limited in this ability. factors that promote normal axolotl regeneration can be examined in mammals to determine if they exhibit altered activity in this context. furthermore, factors prohibiting axolotl regeneration can offer key insight into the mechanisms present in regeneration-incompetent species. we sought to determine if we could experimentally co ...	2017	29302364
limb regeneration in a direct-developing terrestrial salamander, bolitoglossa ramosi (caudata: plethodontidae): limb regeneration in plethodontid salamanders.	appendage regeneration is one of the most compelling phenomena in regenerative biology and is extensively studied in axolotls and newts. however, the regenerative capacity in other families of salamanders remains poorly described. here we characterize the limb regeneration process in bolitoglossa ramosi, a direct-developing terrestrial salamander of the plethodontid family. we (1) describe the major morphological features at different stages of limb regeneration, (2) show that appendage regenera ...	2017	29299325
transcriptional correlates of proximal-distal identify and regeneration timing in axolotl limbs.	cells within salamander limbs retain memories that inform the correct replacement of amputated tissues at different positions along the length of the arm, with proximal and amputations completing regeneration at similar times. we investigated the possibility that positional memory is associated with variation in transcript abundances along the proximal-distal limb axis. transcripts were deeply sampled from ambystoma mexicanum limbs at the time they were administered fore arm vs upper arm amputat ...	2017	29107037
efficient gene knockin in axolotl and its use to test the role of satellite cells in limb regeneration.	salamanders exhibit extensive regenerative capacities and serve as a unique model in regeneration research. however, due to the lack of targeted gene knockin approaches, it has been difficult to label and manipulate some of the cell populations that are crucial for understanding the mechanisms underlying regeneration. here we have established highly efficient gene knockin approaches in the axolotl (ambystoma mexicanum) based on the crispr/cas9 technology. using a homology-independent method, we ...	2017	29087939
salamander spinal cord regeneration: the ultimate positive control in vertebrate spinal cord regeneration.	repairing injured tissues / organs is one of the major challenges for the maintenance of proper organ function in adulthood. in mammals, the central nervous system including the spinal cord, once established during embryonic development, has very limited capacity to regenerate. in contrast, salamanders such as axolotls can fully regenerate the injured spinal cord, making this a very powerful vertebrate model system for studying this process. here we discuss the cellular and molecular requirement ...	2017	29030146
a new and improved algorithm for the quantification of chromatin condensation from microscopic data shows decreased chromatin condensation in regenerating axolotl limb cells.	the nuclear landscape plays an important role in the regulation of tissue and positional specific genes in embryonic and developing cells. changes in this landscape can be dynamic, and are associated with the differentiation of cells during embryogenesis, and the de-differentiation of cells during induced pluripotent stem cell (ipsc) formation and in many cancers. however, tools to quantitatively characterize these changes are limited, especially in the in vivo context, where numerous tissue typ ...	2017	29023511
propofol (2,6-diisopropylphenol) is an applicable immersion anesthetic in the axolotl with potential uses in hemodynamic and neurophysiological experiments.	the mexican axolotl (ambystoma mexicanum) is an important model species in regenerative biology. traditionally, axolotls are anesthetized using benzocaine or ms-222, both of which act to inhibit voltage gated sodium channels thereby preventing action potential propagation. in some neurophysiological experiments this is not desirable; therefore we tested propofol as an alternative anesthetic in the axolotl. we evaluated benzocaine, ms-222, and propofol's cardiovascular effects, effects on action ...	2017	28975032
inhibition of vascular endothelial growth factor receptor decreases regenerative angiogenesis in axolotls.	angiogenesis is crucial for tissue growth and repair in mammals, and is chiefly regulated by vascular endothelial growth factor (vegf) signaling. we evaluated the effect of chemical inhibition of vegf receptor signaling in animals with superior regenerative ability, axolotl salamanders, to determine the impact on vascularization and regenerative outgrowth. following tail amputation, treated animals (100 nm ptk787) and controls were examined microscopically and measured over the month-long period ...	2017	28921926
lineage tracing of genome-edited alleles reveals high fidelity axolotl limb regeneration.	salamanders are unparalleled among tetrapods in their ability to regenerate many structures, including entire limbs, and the study of this ability may provide insights into human regenerative therapies. the complex structure of the limb poses challenges to the investigation of the cellular and molecular basis of its regeneration. using crispr/cas, we genetically labelled unique cell lineages within the developing axolotl embryo and tracked the frequency of each lineage within amputated and fully ...	2017	28917058
comparison of tissue processing methods for microvascular visualization in axolotls.	the vascular system, the pipeline for oxygen and nutrient delivery to tissues, is essential for vertebrate development, growth, injury repair, and regeneration. with their capacity to regenerate entire appendages throughout their lifespan, axolotls are an unparalleled model for vertebrate regeneration, but they lack many of the molecular tools that facilitate vascular imaging in other animal models. the determination of vascular metrics requires high quality image data for the discrimination of ...	2017	28913170
novel axolotl cardiac function analysis method using magnetic resonance imaging.	the salamander axolotl is capable of complete regeneration of amputated heart tissue. however, non-invasive imaging tools for assessing its cardiac function were so far not employed. in this study, cardiac magnetic resonance imaging is introduced as a non-invasive technique to image heart function of axolotls. three axolotls were imaged with magnetic resonance imaging using a retrospectively gated fast low angle shot cine sequence. within one scanning session the axolotl heart was imaged three t ...	2017	28837595
tail regeneration and other phenomena of wound healing and tissue restoration in lizards.	wound healing is a fundamental evolutionary adaptation with two possible outcomes: scar formation or reparative regeneration. scars participate in re-forming the barrier with the external environment and restoring homeostasis to injured tissues, but are well understood to represent dysfunctional replacements. in contrast, reparative regeneration is a tissue-specific program that near-perfectly replicates that which was lost or damaged. although regeneration is best known from salamanders (includ ...	2017	28814609
dii perfusion as a method for vascular visualization in ambystoma mexicanum.	perfusion techniques have been used for centuries to visualize the circulation of tissues. axolotl (ambystoma mexicanum) is a species of salamander that has emerged as an essential model for regeneration studies. little is known about how revascularization occurs in the context of regeneration in these animals. here we report a simple method for visualization of the vasculature in axolotl via perfusion of 1,1'-dioctadecy-3,3,3',3'-tetramethylindocarbocyanine perchlorate (dii). dii is a lipophili ...	2017	28654050
advances in decoding axolotl limb regeneration.	humans and other mammals are limited in their natural abilities to regenerate lost body parts. by contrast, many salamanders are highly regenerative and can spontaneously replace lost limbs even as adults. because salamander limbs are anatomically similar to human limbs, knowing how they regenerate should provide important clues for regenerative medicine. although interest in understanding the mechanics of this process has never wavered, until recently researchers have been vexed by seemingly im ...	2017	28648452
ion channel signaling influences cellular proliferation and phagocyte activity during axolotl tail regeneration.	little is known about the potential for ion channels to regulate cellular behaviors during tissue regeneration. here, we utilized an amphibian tail regeneration assay coupled with a chemical genetic screen to identify ion channel antagonists that altered critical cellular processes during regeneration. inhibition of multiple ion channels either partially (anoctamin1/tmem16a, anoctamin2/tmem16b, kv2.1, kv2.2, l-type cav channels and h/k atpases) or completely (glyr, gabaar, kv1.5 and serca pumps) ...	2017	28603004
a retrospective study of diseases in ambystoma mexicanum: a report of 97 cases.	ambystoma mexicanum kept as pets are affected by a variety of diseases. however, no reports regarding the incidence of specific diseases are available. this study aimed to identify the diseases that occur frequently in this species by surveying the incidence of conditions in pet a. mexicanum specimens brought to a veterinary hospital. the sample comprised 97 pet a. mexicanum individuals brought to the authors' hospital during the 82-month period, i.e., from january 2008 to october 2014. in total ...	2017	28529268
senescence gives insights into the morphogenetic evolution of anamniotes.	senescence represents a mechanism to avoid undesired cell proliferation that plays a role in tumor suppression, wound healing and embryonic development. in order to gain insight on the evolution of senescence, we looked at its presence in developing axolotls (urodele amphibians) and in zebrafish (teleost fish), which are both anamniotes. our data indicate that cellular senescence is present in various developing structures in axolotls (pronephros, olfactory epithelium of nerve fascicles, lateral ...	2017	28500032
a brief history of the study of nerve dependent regeneration.	nerve dependence is a phenomenon observed across a stunning array of species and tissues. from zebrafish to fetal mice to humans, research across various animal models has shown that nerves are critical for the support of tissue repair and regeneration. although the study of this phenomenon has persisted for centuries, largely through research conducted in salamanders, the cellular and molecular mechanisms of nerve dependence remain poorly-understood. here we highlight the near-ubiquity and clin ...	2017	28459075
tissue regeneration in dentistry: can salamanders provide insight?	the ability to regenerate damaged tissues would be of tremendous benefit for medicine and dentistry. unfortunately, humans are unable to regenerate tissues such as teeth and fingers or to repair injured spinal cord. with an aging population, health problems are more prominent and dentistry is no exception as loss of bone tissue in the orofacial sphere from periodontal disease is on the rise. humans can repair oral soft tissues exceptionally well; however, hard tissues, such as bone and teeth, ar ...	2017	28376251
embryonic yolk removal affects neither morphology nor escape performance of larval axolotls.	maternal effects, the influences of maternal phenotype on the phenotypes of her offspring, mediate early ontogenetic traits through maternal investment. in amphibians, provisioning eggs with yolk is the main source of maternal investment. while larger eggs generally result in larger, higher-quality offspring, the relationship between egg size and offspring phenotype is complicated because offspring can evolve to be more or less responsive to variation in yolk provisions. previous studies of seve ...	2017	28365231
data on chemical activation of wnt/β-catenin during axolotl limb regeneration.	limb amputation in axolotls was performed to obtain data demonstrating that a chemical agonist of wnt (int-related protein)/β-catenin signalling can have a role in axolotl limb regeneration (wischin et al., 2017) [1]. the data revealed that active β-catenin protein was present during limb regeneration in some leydig cells in the epithelium; after the chemical treatment, it was observed in more leydig cells. in addition, the chemical agonist of wnt generated distinct limb malformation.	2017	28349103
diffusion tensor tractography reveals muscle reconnection during axolotl limb regeneration.	axolotls have amazing ability to regenerate their lost limbs. our previous works showed that after amputation the remnant muscle ends remained at their original location whilst sending satellite cells into the regenerating parts to develop into early muscle fibers in the late differentiation stage. the parental and the newly formed muscle fibers were not connected until very late stage. the present study used non-invasive diffusion tensor imaging (dti) to monitor weekly axolotl upper arm muscles ...	2017	28253344
repeated removal of developing limb buds permanently reduces appendage size in the highly-regenerative axolotl.	matching appendage size to body size is fundamental to animal function. generating an appropriately-sized appendage is a robust process executed during development which is also critical for regeneration. when challenged, larger animals are programmed to regenerate larger limbs than smaller animals within a single species. understanding this process has important implications for regenerative medicine. to approach this complex question, models with altered appendage size:body size ratios are req ...	2017	28235582
methylene blue assay for estimation of regenerative re-epithelialization in vivo.	the rapidity with which epithelial cells cover a wound surface helps determine whether scarring or scar-less healing results. as methylene blue is a vital dye that is absorbed by damaged tissue but not undamaged epidermis, it can be used to assess wound closure. we sought to develop a quantitative methylene blue exclusion assay to estimate the timeframe for re-epithelialization in regenerating appendages in zebrafish and axolotls, two classic model systems of regeneration. following application ...	2017	28228166
regrow like an axolotl.		2017	28183965