Publications
| Title | Abstract | Year Filter | PMID(sorted descending) Filter |
|---|
| generation of transgenic axolotls (ambystoma mexicanum). | 2009 | 20147240 | |
| axolotl (ambystoma mexicanum) in vitro fertilization. | 2009 | 20147239 | |
| ambystoma mexicanum, the axolotl: a versatile amphibian model for regeneration, development, and evolution studies. | 2009 | 20147230 | |
| molecular cloning and characterization of ligand- and species-specificity of amphibian estrogen receptors. | estrogens are essential for normal reproductive activity in both males and females as well as for ovarian differentiation during a critical developmental stage in most vertebrates. to understand the molecular mechanisms of estrogen action and to evaluate estrogen receptor ligand interactions in amphibians, we isolated cdnas encoding the estrogen receptors (eralpha and erbeta) from the japanese firebelly newt (cynops pyrrhogaster), tokyo salamander (hynobius tokyoensis), axolotl (ambystoma mexica ... | 2010 | 20064516 |
| "origin of the elastic fibres in the heart and aorta of the axolotl and the salmon trout." | 1897 | 19971150 | |
| proteomic analysis of blastema formation in regenerating axolotl limbs. | following amputation, urodele salamander limbs reprogram somatic cells to form a blastema that self-organizes into the missing limb parts to restore the structure and function of the limb. to help understand the molecular basis of blastema formation, we used quantitative label-free liquid chromatography-mass spectrometry/mass spectrometry (lc-ms/ms)-based methods to analyze changes in the proteome that occurred 1, 4 and 7 days post amputation (dpa) through the mid-tibia/fibula of axolotl hind li ... | 2009 | 19948009 |
| neurotrophic regulation of fibroblast dedifferentiation during limb skeletal regeneration in the axolotl (ambystoma mexicanum). | the ability of animals to repair tissue damage is widespread and impressive. among tissues, the repair and remodeling of bone occurs during growth and in response to injury; however, loss of bone above a threshold amount is not regenerated, resulting in a "critical-size defect" (csd). the development of therapies to replace or regenerate a csd is a major focus of research in regenerative medicine and tissue engineering. adult urodeles (salamanders) are unique in their ability to regenerate compl ... | 2010 | 19944088 |
| amelogenin evolution and tetrapod enamel structure. | amelogenins are the major proteins involved in tooth enamel formation. in the present study, we have cloned and sequenced four novel amelogenins from three amphibian species in order to analyze similarities and differences between mammalian and non-mammalian amelogenins. the newly sequenced amphibian amelogenin sequences were from a red-eyed tree frog (litoria chloris) and a mexican axolotl (ambystoma mexicanum). we identified two amelogenin isoforms in the eastern red-backed salamander (plethod ... | 2009 | 19828974 |
| coherent movement of cell layers during wound healing by image correlation spectroscopy. | we have determined the complex sequence of events from the point of injury until reepithelialization in axolotl skin explant model and shown that cell layers move coherently driven by cell swelling after injury. we quantified three-dimensional cell migration using correlation spectroscopy and resolved complex dynamics such as the formation of dislocation points and concerted cell motion. we quantified relative behavior such as velocities and swelling of cells as a function of cell layer during h ... | 2009 | 19804742 |
| sciatic nerve injury model in the axolotl: functional, electrophysiological, and radiographic outcomes. | the 2 aims of this study were as follows: 1) to establish outcome measures of nerve regeneration in an axolotl model of peripheral nerve injury; and 2) to define the timing and completeness of reinnervation in the axolotl following different types of sciatic nerve injury. | 2010 | 19764825 |
| detecting mitoses in time-lapse images of embryonic epithelia using intensity analysis. | although the frequency and orientation of mitoses can significantly affect the mechanics of early embryo development, these data have not been available due to a shortage of suitable automated techniques. fluorescence imaging, though popular, requires biochemical intervention and is not always possible or desirable. here, a new technique that takes advantage of a localized intensity change that occurs in bright field images is used to identify mitoses. the algorithm involves mapping a deformable ... | 2009 | 19757061 |
| myofibril-inducing rna (mir) is essential for tropomyosin expression and myofibrillogenesis in axolotl hearts. | the mexican axolotl, ambystoma mexicanum, carries the naturally-occurring recessive mutant gene 'c' that results in a failure of homozygous (c/c) embryos to form hearts that beat because of an absence of organized myofibrils. our previous studies have shown that a noncoding rna, myofibril-inducing rna (mir), is capable of promoting myofibrillogenesis and heart beating in the mutant (c/c) axolotls. the present study demonstrates that the mir gene is essential for tropomyosin (tm) expression in ax ... | 2009 | 19728883 |
| mir-196 is an essential early-stage regulator of tail regeneration, upstream of key spinal cord patterning events. | salamanders have the remarkable ability to regenerate many body parts following catastrophic injuries, including a fully functional spinal cord following a tail amputation. the molecular basis for how this process is so exquisitely well-regulated, assuring a faithful replication of missing structures every time, remains poorly understood. therefore a study of microrna expression and function during regeneration in the axolotl, ambystoma mexicanum, was undertaken. using microarray-based profiling ... | 2009 | 19682983 |
| acid-sensing ionic-channel functional expression in the vestibular endorgans. | in the vestibular system, the electrical discharge of the afferent neurons has been found to be highly sensitive to external ph changes, and acid-sensing ionic-channels (asic) have been found to be functionally expressed in afferent neurons. no previous attempt to assay the asic function in vestibular afferent neurons has been done. in our work we studied the electrical discharge of the afferent neuron of the isolated inner ear of the axolotl (ambystoma tigrinum) to determine the participation o ... | 2009 | 19660522 |
| memory of fate and position, colorized. | many of our ideas about cellular memory of fate and position come from regeneration studies in salamanders. a popular notion is that cells of the blastema transdifferentiate to different fates during limb regeneration. in a recent issue of nature, tanaka and colleagues challenge this notion. using transplant experiments with gfp-expressing axolotl, they show vividly which cells of the blastema remember their fate and position of origin. | 2009 | 19619486 |
| mathematical model of the cupula-endolymph system with morphological parameters for the axolotl (ambystoma tigrinum) semicircular canals. | by combining mathematical methods with the morphological analysis of the semicircular canals of the axolotl (ambystoma tigrinum), a system of differential equations describing the mechanical coupling in the semicircular canals was obtained. the coefficients of this system have an explicit physiological meaning that allows for the introduction of morphological and dynamical parameters directly into the differential equations. the cupula of the semicircular canals was modeled both as a piston and ... | 2008 | 19593455 |
| cells keep a memory of their tissue origin during axolotl limb regeneration. | during limb regeneration adult tissue is converted into a zone of undifferentiated progenitors called the blastema that reforms the diverse tissues of the limb. previous experiments have led to wide acceptance that limb tissues dedifferentiate to form pluripotent cells. here we have reexamined this question using an integrated gfp transgene to track the major limb tissues during limb regeneration in the salamander ambystoma mexicanum (the axolotl). surprisingly, we find that each tissue produces ... | 2009 | 19571878 |
| the role of nerve signaling in limb genesis and agenesis during axolotl limb regeneration. | 2009 | 19571075 | |
| regeneration and pattern formation - an interview with susan bryant. interviewed by richardson, michael k and chuong, cheng-ming. | susan bryant is one of the leading researchers in regeneration and pattern formation. born in england in 1943, she studied biology at kings college, london (uk). after a ph.d. with angus bellairs on caudal autotomy and regeneration in lizards, she researched urodele regeneration in marcus singer's lab at case western reserve university. then, at the university of california, irvine, she adopted the axolotl as a research model for limb regeneration and pattern formation. her work supported models ... | 2009 | 19557688 |
| epigenetic marks in somatic chromatin are remodelled to resemble pluripotent nuclei by amphibian oocyte extracts. | reprogramming pluripotency after nuclear transplantation shows that molecules in oocytes can remodel somatic chromatin to a stem cell state. here we report on an ex-ovo system using axolotl oocyte extracts to remodel epigenetic marks of somatic chromatin. molecules present in axolotl oocyte extracts induce the reduction of the overall levels of h3k9me3, hp1alpha and dna methylation of somatic cells, and they increase the levels of h3k9ac. the levels of signal intensity detected in treated differ ... | 2009 | 19440040 |
| a model of transcriptional and morphological changes during thyroid hormone-induced metamorphosis of the axolotl. | anuran (frog) metamorphosis has long-served as a model of how thyroid hormones regulate post-embryonic development in vertebrates. however, comparatively little is known about urodele (salamander) metamorphosis. we conducted a detailed time-course study of induced metamorphosis in the mexican axolotl (ambystoma mexicanum) that probed metamorphic changes in morphology and gene expression in the skin. using morphometrics, quantitative pcr, histology, and in situ hybridization we demonstrate that t ... | 2009 | 19275901 |
| amphibian sex determination: segregation and linkage analysis using members of the tiger salamander species complex (ambystoma mexicanum and a. t. tigrinum). | little is known about the genetic basis of sex determination in vertebrates though considerable progress has been made in recent years. in this study, segregation analysis and linkage mapping were performed to localize an amphibian sex-determining locus (ambysex) in the tiger salamander (ambystoma) genome. segregation of sex phenotypes (male and female) among the second generation individuals of interspecific crosses (ambystoma mexicanum x ambystoma tigrinum tigrinum) was consistent with mendeli ... | 2009 | 19259115 |
| evidence for directional selection at a novel major histocompatibility class i marker in wild common frogs (rana temporaria) exposed to a viral pathogen (ranavirus). | whilst the major histocompatibility complex (mhc) is well characterized in the anuran xenopus, this region has not previously been studied in another popular model species, the common frog (rana temporaria). nor, to date, have there been any studies of mhc in wild amphibian host-pathogen systems. we characterise an mhc class i locus in the common frog, and present primers to amplify both the whole region, and specifically the antigen binding region. as no more than two expressed haplotypes were ... | 2009 | 19240796 |
| expression of nkx2.5 in wild type, cardiac mutant, and thyroxine-induced metamorphosed hearts of the mexican axolotl. | nkx2.5, a homeodomain-containing transcription factor, is known to be necessary for normal heart development in vertebrates. it is one of the earliest lineage-restricted genes expressed in cardiovascular progenitor cells and knowledge of its expression patterns has important therapeutic implications for damaged cardiomyocytes. mexican axolotl is a unique system to study heart development for two reasons: the presence of a mutant phenotype lacking organized myofibrils due to sarcomeric tropomyosi ... | 2009 | 19191032 |
| genic regions of a large salamander genome contain long introns and novel genes. | the basis of genome size variation remains an outstanding question because dna sequence data are lacking for organisms with large genomes. sixteen bac clones from the mexican axolotl (ambystoma mexicanum: c-value = 32 x 10(9) bp) were isolated and sequenced to characterize the structure of genic regions. | 2009 | 19144141 |
| microarray and cdna sequence analysis of transcription during nerve-dependent limb regeneration. | microarray analysis and 454 cdna sequencing were used to investigate a centuries-old problem in regenerative biology: the basis of nerve-dependent limb regeneration in salamanders. innervated (nr) and denervated (dl) forelimbs of mexican axolotls were amputated and transcripts were sampled after 0, 5, and 14 days of regeneration. | 2009 | 19144100 |
| cardiovascular physiology and diseases of amphibians. | the class amphibia includes three orders of amphibians: the anurans (frogs and toads), urodeles (salamanders, axolotls, and newts), and caecilians. the diversity of lifestyles across these three orders has accompanying differences in the cardiovascular anatomy and physiology allowing for adaptations to aquatic or terrestrial habitats, pulmonic or gill respiration, hibernation, and body elongation (in the caecilian). this article provides a review of amphibian cardiovascular anatomy and physiolog ... | 2009 | 19131029 |
| detection of mitoses in embryonic epithelia using motion field analysis. | although computer simulations indicate that mitosis may be important to the mechanics of morphogenetic movements, algorithms to identify mitoses in bright field images of embryonic epithelia have not previously been available. here, the authors present an algorithm that identifies mitoses and their orientations based on the motion field between successive images. within this motion field, the algorithm seeks 'mitosis motion field prototypes' characterised by convergent motion in one direction an ... | 2009 | 19051076 |
| regulation of dermal fibroblast dedifferentiation and redifferentiation during wound healing and limb regeneration in the axolotl. | adult urodeles (salamanders) are unique in their ability to regenerate complex organs perfectly. the accessory limb model (alm) in the axolotl allows for the identification of signals from the wound epidermis, nerves and dermal fibroblasts that interact to regenerate a limb. in the present study, we have used the alm to identity the axolotl (ambystoma mexicanum) orthologue of twist (amtwist), a basic helix-loop-helix transcription factor that is involved in the regeneration of the dermis during ... | 2008 | 19046162 |
| axolotl/newt. | 2008 | 19030817 | |
| organophosphorus pesticides effect on early stages of the axolotl ambystoma mexicanum (amphibia: caudata). | ambystoma mexicanum is an endemic salamander of xochimilco, a wetland of the basin of mexico valley. nowadays, axolotl populations are decreasing due environmental stressors. particularly, studies about organophosphorus pesticides (opps; i.e. chlorpyrifos and malathion) toxicity are of great importance due to their intensive use in agricultural activities in xochimilco. thus, the aim of this study was to evaluate under controlled conditions the toxicity of chlorpyrifos (cpf) and malathion (mlt) ... | 2009 | 19012946 |
| working with oocyte nuclei: cytological preparations of active chromatin and nuclear bodies from amphibian germinal vesicles. | the giant nucleus or germinal vesicle (gv) of amphibian oocytes presents a remarkable opportunity to examine nuclear structures in unprecedented levels of detail. by making use of spread preparations of gvs, it is possible to investigate the structure and function of transcription units in active chromatin and a variety of nuclear bodies, all within the limits of resolution of the light microscope. the basic method for producing gv spreads that is described here is based on simple manual dissect ... | 2008 | 18951160 |
| transcriptional response of mexican axolotls to ambystoma tigrinum virus (atv) infection. | very little is known about the immunological responses of amphibians to pathogens that are causing global population declines. we used a custom microarray gene chip to characterize gene expression responses of axolotls (ambystoma mexicanum) to an emerging viral pathogen, ambystoma tigrinum virus (atv). | 2008 | 18937860 |
| the influence of local x-ray treatment on the tail development of the young axolotl, siredon mexicanum. | 1948 | 18934404 | |
| the effect of total brain ablation at stage 28 on subsequent development and behavior in two species of amblystoma. | 1948 | 18889754 | |
| origin and transplantation of melanotic tumor in the axolotl. | 1948 | 18862173 | |
| a comparative proteomic analysis during urodele lens regeneration. | to examine underlying mechanisms of urodele lens regeneration we have employed a proteomic analysis of 650 proteins involved in several signaling pathways. we compared expression of these proteins between the regeneration-competent dorsal iris and the regeneration-incompetent ventral iris in the newt. after a series of screenings we selected several proteins to evaluate their expression quantitatively on immunoblots. we then used these selected proteins to compare their expression between the do ... | 2008 | 18848527 |
| pitx1 expression in developing and regenerating axolotl limbs. | the expression of the homeobox transcription factor pitx1 was investigated in the mexican axolotl (ambystoma mexicanum) during limb development and regeneration by whole-mount mrna in situ hybridizations. this clone shares high amino acid identity with pitx1 from other vertebrates (92% xenopus; 87% chick; 75% human and mouse) within the region isolated. in the developing limbs, pitx1 was expressed in hindlimb mesenchyme, as has been reported in other species. the expression pattern in the hindli ... | 2008 | 18833906 |
| chytridiomycosis in an aquarium collection of frogs: diagnosis, treatment, and control. | the introduction of a new group of dendrobatid frogs to an established captive amphibian collection was followed by several acute mortalities in both resident and introduced frog populations. chytridiomycosis, caused by batrachochytrium dendrobatidis, was diagnosed by histology in two of the dead frogs. following the diagnosis, all amphibians were moved to a specially made quarantine room with strict handling protocols and treated with itraconazole. frogs, being terrestrial amphibians, were trea ... | 2008 | 18817004 |
| regeneration in axolotls: a model to aim for! | urodele amphibians such as the axolotl are the champions of tissue regeneration amongst vertebrates. these animals have mastered the ability to repair and replace most of their tissues following damage or amputation even well into adulthood. in fact it seems that the ability of these organisms to regenerate perfectly is not affected by their age. in addition to being able to regenerate, these animals display a remarkable resistance to cancer. they therefore represent a unique model organism to s ... | 2008 | 18814845 |
| expression cloning of tmem16a as a calcium-activated chloride channel subunit. | calcium-activated chloride channels (caccs) are major regulators of sensory transduction, epithelial secretion, and smooth muscle contraction. other crucial roles of caccs include action potential generation in characean algae and prevention of polyspermia in frog egg membrane. none of the known molecular candidates share properties characteristic of most caccs in native cells. using axolotl oocytes as an expression system, we have identified tmem16a as the xenopus oocyte cacc. the tmem16 family ... | 2008 | 18805094 |
| dual epithelial origin of vertebrate oral teeth. | the oral cavity of vertebrates is generally thought to arise as an ectodermal invagination. consistent with this, oral teeth are proposed to arise exclusively from ectoderm, contributing to tooth enamel epithelium, and from neural crest derived mesenchyme, contributing to dentin and pulp. yet in many vertebrate groups, teeth are not restricted only to the oral cavity, but extend posteriorly as pharyngeal teeth that could be derived either directly from the endodermal epithelium, or from the ecto ... | 2008 | 18794902 |
| glucose transporter distribution in the vessels of the central nervous system of the axolotl ambystoma mexicanum (urodela: ambystomatidae). | the glut-1 isoform of the glucose transporter is commonly considered a reliable molecular marker of blood-brain barrier endothelia in the neural vasculature organized in a three-dimensional network of single vessels. the central nervous system of the axolotl ambystoma mexicanum is characterized by a vascular architecture that contains both single and paired vessels. the presence and distribution of the glut-1 transporter are studied in this urodele using both immunoperoxidase histochemistry and ... | 2008 | 18727107 |
| identification of differentially expressed genes in 4-day axolotl limb blastema by suppression subtractive hybridization. | the goal of our study was the identification of up-regulated genes during axolotl (ambystoma mexicanum) hindlimb regeneration 4 days after amputation using suppression subtractive hybridization (ssh). approximately 400 clones that harbored upregulated genes in regenerating blastema tissue were selected for sequence analysis. a blast homology search against ncbi non-redundant database and an ambystoma est database revealed 102 clones that showed homology to known sequences in genbank with annotat ... | 2008 | 18663994 |
| oleic acid loading does not add to the nephrotoxic effect of albumin in an amphibian and chronic rat model of kidney injury. | under proteinuric conditions, ultrafiltrated albumin can induce an inflammatory and fibrotic response in proximal tubular cells. it is unclear whether albumin per se or compounds bound to albumin are nephrotoxic. some studies have supported the toxicity of albumin-bound fatty acids; however, these compared untreated, fatty acid containing, albumin and delipidated albumin. to prevent confounding by the delipidation procedure, we compared delipidated albumin and oleic acid (oa)-loaded delipidated ... | 2008 | 18653900 |
| chytridiomycosis survey in wild and captive mexican amphibians. | mexico, a rich country in terms of amphibian diversity, hosts about 375 described species. population declines have been documented for several species where it is evident that their habitat is being destroyed or modified. however, other species which inhabit pristine areas are declining as well. it has been suggested that the chytrid fungus batrachochytrium dendrobatidis (b.d.) may be one of the causes of the enigmatic declines in mexico. we surveyed a total of 45 localities, in 12 states acros ... | 2008 | 18648793 |
| structural changes in the proximal tubule of the short-toes axolotl mutant. | a recessive lethal mutation in axolotls that involves the kidneys, the mullerian ducts and the limbs was described by humphrey (1967). in the present experiments, we have examined the structural defects that lead to kidney malfunction and subsequent death in homozygous mutants and compared the defects with those observed in other axolotls lacking this mutant gene. the ultrastructure of the mesonephric kidney was studied in homozygous s/s short-toes axolotls with ascites and/or edema and hemorrha ... | 1991 | 18621179 |
| distribution of sulfhydryloxidase (sox) immunoreactivity in the testis of the axolotl (ambystoma mexicanum) (amphibia, urodela). | immunohistochemical localization of sulfhydryloxidase (sox) has been examined in the testis of the axolotl (ambystoma mexicanum). the urodelan testis contains germ cells in various phases of differentiation from primordial germ cells to mature spermatozoa. sox immunoreactivity is present in mitochondria of primordial germ cells and primary spermatogonia and declines within the population of secondary spermatogonia, suggesting, that the antibody used to localize sox may serve to estimate the deve ... | 1991 | 18621168 |
| endothelial nuclear bulging: morphological evidence for an intraglomerular perfusion regulating mechanism in the axolotl. | kidneys of the axolotl (ambystoma mexicanum: urodela, amphibia) have been investigated by light and electron microscopy as well as microvascular corrosion casting. numerous glomerular endothelial nuclei bulge into the glomerular capillary lumen. it is concluded that these cells virtually stop the blood-flow in the respective vessel by blockage of erythrocyte passage. a proposal for an intraglomerular regulation mechanism of capillary perfusion (and thus filtration) by endothelial isometric contr ... | 1991 | 18621164 |
| primary culture of axolotl spinal cord ependymal cells. | in order to examine the role of ependymal cells in the spinal cord regeneration of urodele amphibians, procedures were established to identify and culture these cells. cell isolation and culture conditions were determined for ependymal cells from larval and adult axolotls (ambystoma mexicanum). dissociated cells prepared from intact spinal cords were cultured on fibronectin- or laminin-coated dishes. dissociated cells attached more rapidly to fibronectin, but attached and spread on both fibronec ... | 1990 | 18620322 |
| a novel protein involved in heart development in ambystoma mexicanum is localized in endoplasmic reticulum. | the discovery of the naturally occurring cardiac non-function (c) animal strain in ambystoma mexicanum (axolotl) provides a valuable animal model to study cardiomyocyte differentiation. in homozygous mutant animals (c/c), rhythmic contractions of the embryonic heart are absent due to a lack of organized myofibrils. we have previously cloned a partial sequence of a peptide cdna (n1) from an anterior-endoderm-conditioned-medium rna library that had been shown to be able to rescue the mutant phenot ... | 2008 | 18563628 |
| neurotrophic regulation of epidermal dedifferentiation during wound healing and limb regeneration in the axolotl (ambystoma mexicanum). | adult urodeles (salamanders) are unique in their ability to regenerate complex organs perfectly. the recently developed accessory limb model (alm) in the axolotl provides an opportunity to identify and characterize the essential signaling events that control the early steps in limb regeneration. the alm demonstrates that limb regeneration progresses in a stepwise fashion that is dependent on signals from the wound epidermis, nerves and dermal fibroblasts from opposite sides of the limb. when all ... | 2008 | 18533144 |
| effects of nitrate on embryos of three amphibian species. | embryos of three aquatic breeding amphibian species, ambystoma mexicanum, hyla chrysoscelis, and rana clamitans, were exposed to increasing levels (0, 5, 10, 30, 60, 100, 300, and 500 mg/l) of nitrate-n (no(3)-) in laboratory, static-renewal experiments. lethal effects were recorded from gosner stage 2 (h. chrysoscelis and r. clamitans) or harrison stage 2 (a. mexicanum) to time of hatching. date of hatching and length at hatching were also compared between treatments for a. mexicanum. no signif ... | 2008 | 18496633 |
| multi-scale finite element modeling allows the mechanics of amphibian neurulation to be elucidated. | the novel multi-scale computational approach introduced here makes possible a new means for testing hypotheses about the forces that drive specific morphogenetic movements. a 3d model based on this approach is used to investigate neurulation in the axolotl (ambystoma mexicanum), a type of amphibian. the model is based on geometric data from 3d surface reconstructions of live embryos and from serial sections. tissue properties are described by a system of cell-based constitutive equations, and pa ... | 2008 | 18408255 |
| orexin-a immunoreactive cells and fibers in the central nervous system of the axolotl brain and their association with tyrosine hydroxylase and serotonin immunoreactive somata. | orexin-a-like immunoreactivity in the axolotl brain was investigated by immunohistochemistry. immunoreactive somata formed a single group in the hypothalamus, but were distributed beyond several nuclei, namely, the ventral aspect of the nucleus preopticus posterior, dorsal aspect of the nucleus suprachiasmaticus and anterior aspect of the pars ventralis hypothalami. immunoreactive fibers were distributed throughout the brain from the olfactory bulb to the spinal cord except the cerebellum. the d ... | 2008 | 18378425 |
| all about axolotls. | 2008 | 18356918 | |
| analysis of the expression and function of wnt-5a and wnt-5b in developing and regenerating axolotl (ambystoma mexicanum) limbs. | urodele amphibians are unique adult vertebrates because they are able to regenerate body parts after amputation. studies of urodele limb regeneration, the key model system for vertebrate regeneration, have led to an understanding of the origin of blastema cells and the importance of positional interactions between blastema cells in the control of growth and pattern formation. progress is now being made in the identification of the signaling pathways that regulate dedifferentiation, blastema morp ... | 2008 | 18336582 |
| conserved pattern of otp-positive cells in the paraventricular nucleus and other hypothalamic sites of tetrapods. | the paraventricular nucleus complex (pa) is a component of central neural circuitry that regulates several homeostatic variables. the paraventricular nucleus is composed of magnocellular neurons that project to the posterior pituitary and parvicellular neurons that project to numerous sites in the central nervous system. according to the revised prosomeric model, the paraventricular nucleus is located caudal to the eye stalk along the rostrocaudal dimension of the dorsal hypothalamic alar plate. ... | 2008 | 18331876 |
| igx antibodies in the urodele amphibian ambystoma mexicanum. | until recently, it was believed that urodele amphibians are able to synthesize only two immunoglobulin isotypes, igm and igy. we reinvestigated this issue in the iberian ribbed newt pleurodeles waltl and reported recently that this urodele expresses at least three isotypes: igm, igp and igy. in this study, we demonstrate that another urodele, ambystoma mexicanum, has also a third isotype whose amino acid sequence presents the highest homology with the amino acid sequence of xenopus igx. this iso ... | 2008 | 18280565 |
| effect of thyroid hormone concentration on the transcriptional response underlying induced metamorphosis in the mexican axolotl (ambystoma). | thyroid hormones (th) induce gene expression programs that orchestrate amphibian metamorphosis. in contrast to anurans, many salamanders do not undergo metamorphosis in nature. however, they can be induced to undergo metamorphosis via exposure to thyroxine (t4). we induced metamorphosis in juvenile mexican axolotls (ambystoma mexicanum) using 5 and 50 nm t4, collected epidermal tissue from the head at four time points (days 0, 2, 12, 28), and used microarray analysis to quantify mrna abundances. | 2008 | 18267027 |
| calcium waves. | waves through living systems are best characterized by their speeds at 20 degrees c. these speeds vary from those of calcium action potentials to those of ultraslow ones which move at 1-10 and/or 10-20 nm s(-1). all such waves are known or inferred to be calcium waves. the two classes of calcium waves which include ones with important morphogenetic effects are slow waves that move at 0.2-2 microm s(-1) and ultraslow ones. both may be propagated by cycles in which the entry of calcium through the ... | 2008 | 18192175 |
| the influence of the corticotropic hormone from ox on the active salt uptake in the axolotl. | 1949 | 18129272 | |
| reversal of sex in females of genotype ww in the axolotl (siredon or ambystoma mexicanum) and its bearing upon the role of the z chromosomes in the development of the testis. | 1948 | 18101409 | |
| localized co-transcriptional recruitment of the multifunctional rna-binding protein celf1 by lampbrush chromosome transcription units. | the highly-extended transcription units of lampbrush chromosomes (lbcs) offer unique opportunities to study the co-transcriptional events occurring on nascent transcripts. using lbcs from amphibian oocytes, i investigated whether celf1, an rna binding protein involved in the regulation of alternative splicing, mrna stability and translation, is localized to active transcription units. antibodies raised against mammalian (cug-bp1) and amphibian (eden-bp) celf1 were used to immunostain lbc spreads ... | 2007 | 18095176 |
| transforming growth factor: beta signaling is essential for limb regeneration in axolotls. | axolotls (urodele amphibians) have the unique ability, among vertebrates, to perfectly regenerate many parts of their body including limbs, tail, jaw and spinal cord following injury or amputation. the axolotl limb is the most widely used structure as an experimental model to study tissue regeneration. the process is well characterized, requiring multiple cellular and molecular mechanisms. the preparation phase represents the first part of the regeneration process which includes wound healing, c ... | 2007 | 18043735 |
| a clash of traditions: the history of comparative and experimental embryology in sweden as exemplified by the research of gösta jägersten and sven hörstadius. | until the 1940s research traditions were often imported from germany to sweden, and young scientists went to german universities to learn new techniques and get in touch with the latest ideas. in developmental biology, the comparative, phylogenetic embryology advocated most forcefully by ernst haeckel co-existed with the "entwickelungsmechanik" tradition developed by wilhelm his, wilheln roux and others partly as a reaction to haeckel's ideas. i use the zoology department at uppsala university a ... | 2007 | 18008099 |
| evidence for balancing selection at the dab locus in the axolotl, ambystoma mexicanum. | the axolotl (ambystoma mexicanum) has been characterized as immunodeficient, and the absence of major histocompatibility complex (mhc) class ii polymorphism has been cited as a possible explanation. here we present evidence for considerable allelic polymorphism at the mhc class ii dab locus for a sample of wild-caught axolotls. evidence that these sequences are the product of balancing selection for disease resistance is discussed. | 2007 | 18001306 |
| chondrogenesis and ossification of the lissamphibian pectoral girdle. | knowledge of amphibian shoulder development is requisite for further understanding of gnathostome pectoral girdle evolution. fish and amniotes share few pectoral girdle elements, but modern amphibians exhibit a unique combination of traits that bridge the morphological gap between these two groups. i analyzed patterns of chondrogenesis, ossification, and bone histology of the pectoral girdles of two anuran species (xenopus laevis and bombina orientalis) and two urodele species (ambystoma mexican ... | 2008 | 17999401 |
| a reduction of tropomyosin limits development of sarcomeric structures in cardiac mutant hearts of the mexican axolotl. | the cardiac lethal mutation in mexican axolotl (ambystoma mexicanum) results in a lack of contractions in the ventricle of mutant embryos. previous studies have demonstrated that tropomyosin, a component of thin filaments, is greatly reduced in mutant hearts lacking myofibril organization. confocal microscopy was used to examine the structure and comparative amount of tropomyosin at heartbeat initiation and at a later stage. the formation of functional sarcomeres coincided with contractions in n ... | 2007 | 17990128 |
| muscular derivatives of the cranialmost somites revealed by long-term fate mapping in the mexican axolotl (ambystoma mexicanum). | the fate of single somites has not been analyzed from a comparative perspective with modern cell-marking methods. most of what we know is based on work using quail-chick chimeras. consequently, to what degree cell fate has been conserved despite the anatomical differences among vertebrates is unknown. we have analyzed the cell fate of the cranialmost somites, with the focus on somite two, in the mexican axolotl (ambystoma mexicanum). somite cells were marked by injection of dextran-fluorescein a ... | 2007 | 17976053 |
| nerve-induced ectopic limb blastemas in the axolotl are equivalent to amputation-induced blastemas. | adult urodeles (salamanders) are unique in their ability to regenerate complex organs perfectly. the recently developed accessory limb model (alm) in the axolotl provides an opportunity to identify and characterize the essential signaling events that control the early steps in limb regeneration. the alm demonstrates that limb regeneration progresses in a stepwise fashion that is dependent on signals from the wound epidermis, nerves and dermal fibroblasts from opposite sides of the limb. when all ... | 2007 | 17959163 |
| urodele p53 tolerates amino acid changes found in p53 variants linked to human cancer. | urodele amphibians like the axolotl are unique among vertebrates in their ability to regenerate and their resistance to develop cancers. it is unknown whether these traits are linked at the molecular level. | 2007 | 17903248 |
| the mexican axolotl and its susceptibility to transformations. | 1885 | 17837280 | |
| the mexican axolotl, and its susceptibility-to transformations. | 1885 | 17808850 | |
| mutant genes in the mexican axolotl. | 1974 | 17756293 | |
| an infectious disease causing wide-spread necrosis in the liver of the mexican axolotl. | 1937 | 17732647 | |
| bone morphogenetic protein-4 and noggin signaling regulates pigment cell distribution in the axolotl trunk. | wild-type (dark) and white mutant axolotl (ambystoma mexicanum) embryos were used to investigate the role of the secreted growth factor bone morphogenetic protein-4 (bmp-4) and its antagonist, noggin, in dorso-lateral trunk neural crest (nc) migration. implantation of a bmp-4-coated microbead caused a melanophore-free zone around the bead, reduction of the dorsal fin above the bead, and disappearance of myotome tissue. we established a novel method that allows controlled induction of protein syn ... | 2008 | 17662068 |
| the short toes mutation of the axolotl. | the axolotl mutant strain, short toes (s/s), can regenerate spinal cord and tail, but not limbs. this makes s/s potentially very useful for limb regeneration studies. this mutant merits a new examination that integrates the original description of the mutant, existing experimental studies, new data and current thinking about stem cells and regeneration. there are still major gaps in information about this mutant; the gene(s) causing the defects has not yet been discovered, and even the histologi ... | 2007 | 17661741 |
| bmp-4 and noggin signaling modulate dorsal fin and somite development in the axolotl trunk. | bmp-4, a member of the tgf-beta superfamily of growth factors, is involved in various developmental processes. we investigated the effects of bmp-4 and its antagonist noggin on axolotl trunk development. implantation of bmp-4-coated microbeads caused inhibition of muscle and dorsal fin formation in the vicinity of the microbeads. at some distance, myotomes developed with reduced height but increased width, which was accompanied by increased cell proliferation. these effects could be modulated by ... | 2007 | 17654602 |
| highly restricted diversity of tcr delta chains of the amphibian mexican axolotl (ambystoma mexicanum) in peripheral tissues. | gammadelta t cells localize at mammalian epithelial surfaces to exert both protective and regulatory roles in response to infections. we have previously characterized the mexican axolotl (ambystoma mexicanum) t cell receptor delta (trd) chain. in this study, trd repertoires in spleen, liver, intestine and skin from larvae, pre-adult and adult axolotls were examined and compared to the thymic trd repertoire. a trdv transcript without n/d diversity, trdv1s1-trdj1, dominates the trd repertoires unt ... | 2007 | 17523213 |
| a clonal analysis of neural progenitors during axolotl spinal cord regeneration reveals evidence for both spatially restricted and multipotent progenitors. | complete regeneration of the spinal cord occurs after tail regeneration in urodele amphibians such as the axolotl. little is known about how neural progenitor cells are recruited from the mature tail, how they populate the regenerating spinal cord, and whether the neural progenitor cells are multipotent. to address these issues we used three types of cell fate mapping. by grafting green fluorescent protein-positive (gfp(+)) spinal cord we show that a 500 microm region adjacent to the amputation ... | 2007 | 17507409 |
| comparative analysis of xenopus vegt, the meso-endodermal determinant, identifies an unusual conserved sequence. | the transcription factor, vegt, is the meso-endodermal determinant in xenopus laevis. we examined vegt orthologs from several anuran amphibians and the urodele amphibian, the mexican axolotl. in addition to the conserved t-box, the dna-binding domain, the orthologs share a conserved 57 amino acid domain at the c-terminal. most striking is a 17-nucleotide (nt) sequence near the 3' end of the open reading frame. the 17 nts are absolutely conserved among the anurans, whose last common ancestor live ... | 2007 | 17459091 |
| ranavirus-associated mass mortality in imported red tailed knobby newts (tylototriton kweichowensis): a case report. | a mass die-off of imported red tailed knobby newts (tylototriton kweichowensis) occurred in 2004 in belgium and the netherlands. in addition to massive infection with rhabdias tokyoensis, ranavirus was isolated from three dead newts examined virologically and the gene coding for the major capsid protein of the virus was sequenced. the isolate showed 99.8% similarity to the published sequence of frog virus 3. upon experimental infection of axolotls (ambystoma mexicanum) with this isolate, no mark ... | 2008 | 17449300 |
| characterization and expression of a maternal axolotl cyclin b1 during oogenesis and early development. | the m phase promoting factor (mpf) is a dimer composed of a catalytic cdk1 subunit and a cyclin b regulatory subunit. we have characterized a cdna containing the entire coding sequence of an axolotl cyclin b1 protein that is able to promote mpf activity when added to a fraction from prophase i oocytes that contains monomeric cdk1. the axolotl cyclin b1 gene is expressed as a maternal mrna in oocytes and early embryos. its poly(a) tail length increases in metaphase ii oocytes and then decreases r ... | 2007 | 17428262 |
| modulation of the reaction cycle of the na+:ca2+, k+ exchanger. | ca(2+) concentration in retinal photoreceptor rod outer segment (os) strongly affects the generator potential kinetics and the receptor light adaptation. the response to intense light stimuli delivered in the dark produce potential changes exceeding 40 mv: since the ca(2+) extrusion in the os is entirely controlled by the na(+):ca(2+), k(+) exchanger, it is important to assess how the exchanger ion transport rate is affected by the voltage and, in general, by intracellular factors. it is indeed ... | 2007 | 17415556 |
| role of myofibril-inducing rna in cardiac tnt expression in developing mexican axolotl. | the mexican axolotl, ambystoma mexicanum, has been a useful animal model to study heart development and cardiac myofibrillogenesis. a naturally-occurring recessive mutant, gene "c", for cardiac non-function in the mexican axolotl causes a failure of myofibrillogenesis due to a lack of tropomyosin expression in homozygous mutant (c/c) embryonic hearts. myofibril-inducing rna (mir) rescues mutant hearts in vitro by promoting tropomyosin expression and myofibril formation thereafter. we have studie ... | 2007 | 17408593 |
| isolation and characterization of axolotl npdc-1 and its effects on retinoic acid receptor signaling. | retinoic acid, a key morphogen in early vertebrate development and tissue regeneration, mediates its effects through the binding of receptors that act as ligand-induced transcription factors. these binding events function to recruit an array of transcription co-regulatory proteins to specific gene promoters. one such co-regulatory protein, neuronal proliferation and differentiation control-1 (npdc-1), is broadly expressed during mammalian development and functions as an in vitro repressor of ret ... | 2007 | 17331771 |
| tropomodulin expression in developing hearts of normal and cardiac mutant mexican axolotl. | in the axolotl, ambystoma mexicanum, a simple, recessive cardiac-lethal mutation in gene "c" results in the hearts of c/c homozygous animals being deficient in sarcomeric tropomyosin (tm) and failing to form mature myofibrils. subsequently, the mutant hearts do not beat. a three-step model of myofibril assembly recently developed in cell culture prompted a reassessment of the myofibril assembly process in mutant hearts using a relatively new late marker for thin filament assembly, tropomodulin ( ... | 2006 | 17303917 |
| mapping centromeres in the axolotl. | 1956 | 17247612 | |
| early gene expression during natural spinal cord regeneration in the salamander ambystoma mexicanum. | in contrast to mammals, salamanders have a remarkable ability to regenerate their spinal cord and recover full movement and function after tail amputation. to identify genes that may be associated with this greater regenerative ability, we designed an oligonucleotide microarray and profiled early gene expression during natural spinal cord regeneration in ambystoma mexicanum. we sampled tissue at five early time points after tail amputation and identified genes that registered significant changes ... | 2007 | 17241119 |
| measurement of in vivo stress resultants in neurulation-stage amphibian embryos. | in order to obtain the first quantitative measurements of the in vivo stresses in early-stage amphibian embryos, we developed a novel instrument that uses a pair of parallel wires that are glued to the surface of an embryo normal to the direction in which the stress is to be determined. when a slit is made parallel to the wires and between them, tension in the surrounding tissue causes the slit to open. under computer control, one of the wires is moved so as to restore the original wire spacing, ... | 2007 | 17237990 |
| curious dropsical condition of an axolotl. | 1887 | 17231716 | |
| limb regeneration in axolotl: is it superhealing? | the ability of axolotls to regenerate their limbs is almost legendary. in fact, urodeles such as the axolotl are the only vertebrates that can regenerate multiple structures like their limbs, jaws, tail, spinal cord, and skin (the list goes on) throughout their lives. it is therefore surprising to realize, although we have known of their regenerative potential for over 200 years, how little we understand the mechanisms behind this achievement of adult tissue morphogenesis. many observations can ... | 2006 | 17205184 |
| migratory patterns and developmental potential of trunk neural crest cells in the axolotl embryo. | using cell markers and grafting, we examined the timing of migration and developmental potential of trunk neural crest cells in axolotl. no obvious differences in pathway choice were noted for dii-labeling at different lateral or medial positions of the trunk neural folds in neurulae, which contributed not only to neural crest but also to rohon-beard neurons. labeling wild-type dorsal trunks at pre- and early-migratory stages revealed that individual neural crest cells migrate away from the neur ... | 2007 | 17183528 |
| [the era of the axolotls: speculations regarding the neurobiological modifications during the adolescence]. | the article summarizes a number of recent findings about the brain changes which take place during the adolescence and the youth, their relations with their behavior and some questions are formulated with regard to the deepening of these hypothesis. | 2014 | 17146500 |
| inhibition of sonic hedgehog signaling leads to posterior digit loss in ambystoma mexicanum: parallels to natural digit reduction in urodeles. | molecular mechanisms patterning the tetrapod limb, including anterior-posterior axis determination involving sonic hedgehog (shh), have received much attention, particularly in amniotes. anterior-posterior patterning in urodele amphibians differs radically from that of amniotes in that it shows a pronounced anterior-to-posterior sequence of digit development. in contrast, amniotes develop their digits almost simultaneously with a slight posterior-to-anterior polarity. here we use cyclopamine, an ... | 2007 | 17117438 |
| wnt/beta-catenin signaling regulates vertebrate limb regeneration. | the cellular and molecular bases allowing tissue regeneration are not well understood. by performing gain- and loss-of-function experiments of specific members of the wnt pathway during appendage regeneration, we demonstrate that this pathway is not only necessary for regeneration to occur, but it is also able to promote regeneration in axolotl, xenopus, and zebrafish. furthermore, we show that changes in the spatiotemporal distribution of beta-catenin in the developing chick embryo elicit apica ... | 2006 | 17114576 |
| changes in oxygen consumption during metamorphosis induced by thyroid administration in the axolotl. | 1927 | 16993919 | |
| microarray analysis identifies keratin loci as sensitive biomarkers for thyroid hormone disruption in the salamander ambystoma mexicanum. | ambystomatid salamanders offer several advantages for endocrine disruption research, including genomic and bioinformatics resources, an accessible laboratory model (ambystoma mexicanum), and natural lineages that are broadly distributed among north american habitats. we used microarray analysis to measure the relative abundance of transcripts isolated from a. mexicanum epidermis (skin) after exogenous application of thyroid hormone (th). only one gene had a >2-fold change in transcript abundance ... | 2007 | 16926121 |
| rna of amvegt, the axolotl orthologue of the xenopus meso-endodermal determinant, is not localized in the oocyte. | the transcription factor, vegt, is the meso-endodermal determinant in xenopus laevis, and the localization of vegt rna to the vegetal cortex of the oocyte is an important starting point for embryonic patterning. we have cloned the vegt orthologue from the urodele amphibian, ambystoma mexicanum, the mexican axolotl. axolotl vegt (amvegt) is expressed zygotically in the presumptive mesoderm and rohon-beard neurons as in x. laevis, and its expression persists at the tip of the tail as with zebrafis ... | 2007 | 16920404 |