Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| an ambystoma mexicanum est sequencing project: analysis of 17,352 expressed sequence tags from embryonic and regenerating blastema cdna libraries. | the ambystomatid salamander, ambystoma mexicanum (axolotl), is an important model organism in evolutionary and regeneration research but relatively little sequence information has so far been available. this is a major limitation for molecular studies on caudate development, regeneration and evolution. to address this lack of sequence information we have generated an expressed sequence tag (est) database for a. mexicanum. | 2004 | 15345051 |
| role of cranial neural crest cells in visceral arch muscle positioning and morphogenesis in the mexican axolotl, ambystoma mexicanum. | the role of cranial neural crest cells in the formation of visceral arch musculature was investigated in the mexican axolotl, ambystoma mexicanum. dii (1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine, perchlorate) labeling and green fluorescent protein (gfp) mrna injections combined with unilateral transplantations of neural folds showed that neural crest cells contribute to the connective tissues but not the myofibers of developing visceral arch muscles in the mandibular, hyoid, and bran ... | 2004 | 15366001 |
| [the inhibitory action of thiouracil on the melanogenesis of the regenerating tail of axolotl]. | 1950 | 15421315 | |
| [isolated action of different hormones on the metamorphosis of hypophysectomized axolotls]. | 1950 | 15421580 | |
| biochemical gradients in the axolotl gastrula. | 1950 | 15444065 | |
| an introduction to the mexican axolotl (ambystoma mexicanum). | a number of unusual traits, including a remarkable capacity for wound healing and limb regeneration, make the axolotl an interesting animal model. the author provides an overview of axolotl care and use in biomedical research. | 2004 | 15457201 |
| gene expression in the axolotl germ line: axdazl, axvh, axoct-4, and axkit. | primordial germ cells (pgcs) in embryos of mammals and urodele amphibians are formed by induction in the absence of germ plasm. we describe expression of four germ cell-related genes through the germ cell cycle of the axolotl. the orthologs of vasa and daz-like are up-regulated in pgcs of tail bud embryos before the gonad forms and are expressed throughout the female germ cell cycle. mammalian oct-4 is a marker of pluripotency in embryonic cells. axolotl oct-4 has higher homology to oct-4 than t ... | 2004 | 15517581 |
| developmental origins and evolution of jaws: new interpretation of "maxillary" and "mandibular". | cartilage of the vertebrate jaw is derived from cranial neural crest cells that migrate to the first pharyngeal arch and form a dorsal "maxillary" and a ventral "mandibular" condensation. it has been assumed that the former gives rise to palatoquadrate and the latter to meckel's (mandibular) cartilage. in anamniotes, these condensations were thought to form the framework for the bones of the adult jaw and, in amniotes, appear to prefigure the maxillary and mandibular facial prominences. here, we ... | 2004 | 15531376 |
| quantitative evaluation of morpholino-mediated protein knockdown of gfp, msx1, and pax7 during tail regeneration in ambystoma mexicanum. | vertebrate regeneration is a fascinating but poorly understood biological phenomena. urodele amphibians such as ambystoma mexicanum (the axolotl) can functionally regenerate complex body structures such as the limb and tail, including the spinal cord, throughout life. so far, molecular studies on regeneration have been limited due to the paucity of tools for knocking-down gene and protein function. in this article, we quantitatively assessed the ability of morpholinos to specifically down-regula ... | 2005 | 15580632 |
| isoproterenol-produced damage in amphibian heart could be mediated by adrenergic receptors located in the heart muscle. | in mammals, isoproterenol may produce heart damage in part by binding to adrenergic receptors in the coronary arteries. previously we showed evidence that isoproterenol produces cellular necrosis and interstitial fibrosis in the ventricle of the heart of an amphibian, which has no coronary arteries. the present study examines responses to 3-adrenergic receptor stimulation in the heart of urodele amphibians. the hearts from three amphibians; ambystoma mexicanum, a. tigrinum and a. dumerilii were ... | 2004 | 15633614 |
| evidence for emergence of an amphibian iridoviral disease because of human-enhanced spread. | our understanding of origins and spread of emerging infectious diseases has increased dramatically because of recent applications of phylogenetic theory. iridoviruses are emerging pathogens that cause global amphibian epizootics, including tiger salamander (ambystoma tigrinum) die-offs throughout western north america. to explain phylogeographical relationships and potential causes for emergence of western north american salamander iridovirus strains, we sequenced major capsid protein and dna me ... | 2005 | 15643965 |
| cardiac myofibril formation is not affected by modification of both n- and c-termini of sarcomeric tropomyosin. | although the role of tropomyosin is well-defined in striated muscle, the precise mechanism of how tropomyosin functions is still unclear. it has been shown that extension of either n- or c-terminal ends of sarcomeric tropomyosin do not affect cardiac myofibrillogenesis, but it is not known whether simultaneous extension of both ends affects the process. for studying structural/functional relationships of sarcomeric tropomyosin, we have chosen the ambystoma mexicanum because cardiac mutant hearts ... | 2005 | 15738580 |
| diminished myofibril organization in mutant axolotl hearts transfected with site-directed mutants of sarcomeric tropomyosins. | we used a model lacking endogenous sarcomeric tropomyosin, the cardiac mutant of the mexican axolotl, to examine the effect of mutant tropomyosins on sarcomeric myofibril formation. previous studies have introduced wild-type mouse alpha-tropomyosin into mutant hearts in organ culture with subsequent for-mation of organized myofibrils. this study examines the predominant embry-onic axolotl tpm-4 type tropomyosin (tpm4alpha), containing a conservative re- placement of glutamic acid for aspartic ac ... | 2005 | 15738587 |
| haem conformation of amphibian nytrosylhaemoglobins detected by xanes spectroscopy. | we investigated for the first time the haem stereochemistry in the nitrosylated derivative of two amphibian haemoglobins, xenopus laevis and ambystoma mexicanum, by means of x-ray absorption spectroscopy technique with the aim to explain the relationships between the active site structure and physiological function of these proteins, compared to that from humans. our results show that while the fe site local structure of human hbno is modulated by an allosteric effector such as ihp shifting the ... | 2005 | 15744461 |
| transcriptional and phylogenetic analysis of five complete ambystomatid salamander mitochondrial genomes. | we report on a study that extended mitochondrial transcript information from a recent est project to obtain complete mitochondrial genome sequence for 5 tiger salamander complex species (ambystoma mexicanum, a. t. tigrinum, a. andersoni, a. californiense, and a. dumerilii). we describe, for the first time, aspects of mitochondrial transcription in a representative amphibian, and then use complete mitochondrial sequence data to examine salamander phylogeny at both deep and shallow levels of evolu ... | 2005 | 15780978 |
| anti-sense-mediated inhibition of expression of the novel striated tropomyosin isoform tpm1kappa disrupts myofibril organization in embryonic axolotl hearts. | striated muscle tropomyosin (tm) is described as containing ten exons; 1a, 2b, 3, 4, 5, 6b, 7, 8, and 9a/b. exon 9a/b has critical troponin binding domains and is found in striated muscle isoforms. we have recently discovered a smooth (exon 2a)/striated (exons 9a/b) isoform expressed in amphibian, avian, and mammalian hearts, designated as an isoform of the tpm1 gene (tpm1kappa). tpm1kappa expression was blocked in whole embryonic axolotl heart by transfection of exon-specific anti-sense oligonu ... | 2005 | 15838882 |
| limb chondrogenesis of the seepage salamander, desmognathus aeneus (amphibia: plethodontidae). | salamanders are infrequently mentioned in analyses of tetrapod limb formation, as their development varies considerably from that of amniotes. however, urodeles provide an opportunity to study how limb ontogeny varies with major differences in life history. here we assess limb development in desmognathus aeneus, a direct-developing salamander, and compare it to patterns seen in salamanders with larval stages (e.g., ambystoma mexicanum). both modes of development result in a limb that is morpholo ... | 2005 | 15880507 |
| expression of heat-shock protein 70 during limb development and regeneration in the axolotl. | urodele amphibians (e.g., axolotls) have the unique ability, among vertebrates, to regenerate perfectly many parts of their body after amputation. the limb has been the most widely studied regenerating structure in these organisms and provides an ideal model in which to understand how vertebrates can regenerate complex tissues. the present study focuses on hsp-70, a member of the stress-related heat-shock protein family. this protein is normally induced after a stress or trauma such as heat-shoc ... | 2005 | 15965983 |
| hedgehog signaling controls dorsoventral patterning, blastema cell proliferation and cartilage induction during axolotl tail regeneration. | tail regeneration in urodeles requires the coordinated growth and patterning of the regenerating tissues types, including the spinal cord, cartilage and muscle. the dorsoventral (dv) orientation of the spinal cord at the amputation plane determines the dv patterning of the regenerating spinal cord as well as the patterning of surrounding tissues such as cartilage. we investigated this phenomenon on a molecular level. both the mature and regenerating axolotl spinal cord express molecular markers ... | 2005 | 15983402 |
| corticotropin-releasing hormone-mediated metamorphosis in the neotenic axolotl ambystoma mexicanum: synergistic involvement of thyroxine and corticoids on brain type ii deiodinase. | in the present study, morphological changes leading to complete metamorphosis have been induced in the neotenic axolotl ambystoma mexicanum using a submetamorphic dose of t(4) together with an injection of corticotropin-releasing hormone (crh). an injection of crh alone is ineffective in this regard presumably due to a lack of thyrotropic stimulation. using this low hormone profile for induction of metamorphosis, the deiodinating enzymes d2 and d3 known to be present in amphibians were measured ... | 2005 | 15993107 |
| multiview robotic microscope reveals the in-plane kinematics of amphibian neurulation. | a new robotic microscope system, called the frogatron 3000, was developed to collect time-lapse images from arbitrary viewing angles over the surface of live embryos. embryos are mounted at the center of a horizontal, fluid-filled, cylindrical glass chamber around which a camera with special optics traverses. to hold them at the center of the chamber and revolve them about a vertical axis, the embryos are placed on the end of a small vertical glass tube that is rotated under computer control. to ... | 2005 | 16078621 |
| a comprehensive expressed sequence tag linkage map for tiger salamander and mexican axolotl: enabling gene mapping and comparative genomics in ambystoma. | expressed sequence tag (est) markers were developed for ambystoma tigrinum tigrinum (eastern tiger salamander) and for a. mexicanum (mexican axolotl) to generate the first comprehensive linkage map for these model amphibians. we identified 14 large linkage groups (125.5-836.7 cm) that presumably correspond to the 14 haploid chromosomes in the ambystoma genome. the extent of genome coverage for these linkage groups is apparently high because the total map size (5251 cm) falls within the range of ... | 2005 | 16079226 |
| tensile properties of embryonic epithelia measured using a novel instrument. | we present the first measurements of the tensile properties of embryonic epithelia, data that are crucial to understanding the mechanics of morphogenetic movements. fine wires were glued to the surface of an intact, live embryo using cyanoacrylate glue, after which the epithelium between the wires was separated from the remainder of the embryo by microsurgery. the wires were then separated from each other in 0.1 microm steps under computer control in order to elongate the tissue at a constant tr ... | 2005 | 16084209 |
| proximodistal identity during vertebrate limb regeneration is regulated by meis homeodomain proteins. | the mechanisms by which cells obtain instructions to precisely re-create the missing parts of an organ remain an unresolved question in regenerative biology. urodele limb regeneration is a powerful model in which to study these mechanisms. following limb amputation, blastema cells interpret the proximal-most positional identity in the stump to reproduce missing parts faithfully. classical experiments showed the ability of retinoic acid (ra) to proximalize blastema positional values. meis homeobo ... | 2005 | 16107473 |
| automated 3-d reconstruction of the surface of live early-stage amphibian embryos. | although three-dimensional (3-d) reconstructions of the surfaces of live embyos are vital to understanding embryo development, morphogenetic tissue movements and other factors have prevented the automation of this task. here, we report an integrated set of software algorithms that overcome these challenges, making it possible to completely automate the reconstruction of embryo surfaces and other textured surfaces from multiview images. the process involves: 1) building accurate point corresponde ... | 2005 | 16119236 |
| axolotl hemoglobin: cdna-derived amino acid sequences of two alpha globins and a beta globin from an adult ambystoma mexicanum. | erythrocytes of the adult axolotl, ambystoma mexicanum, have multiple hemoglobins. we separated and purified two kinds of hemoglobin, termed major hemoglobin (hb m) and minor hemoglobin (hb m), from a five-year-old male by hydrophobic interaction column chromatography on alkyl superose. the hemoglobins have two distinct alpha type globin polypeptides (alpham and alpham) and a common beta globin polypeptide, all of which were purified in fplc on a reversed-phase column after s-pyridylethylation. ... | 2005 | 16143550 |
| molecular characterization of major histocompatibility complex class ii alleles in wild tiger salamanders (ambystoma tigrinum). | major histocompatibility complex (mhc) class ii genes are usually among the most polymorphic in vertebrate genomes because of their critical role (antigen presentation) in immune response. prior to this study, the mhc was poorly characterized in tiger salamanders (ambystoma tigrinum), but the congeneric axolotl (ambystoma mexicanum) is thought to have an unusual mhc. most notably, axolotl class ii genes lack allelic variation and possess a splice variant without a full peptide binding region (pb ... | 2005 | 16195876 |
| nitric oxide in the amphibian (ambystoma tigrinum) lateral line. | nicotinamide adenine dinucleotide phosphate reduced-diaphorase (nadph-d) histochemistry was investigated in the axolotl (ambystoma tigrinum) lateral line. hair cells of neuromast organs of the head skin and neurons of the postotic ganglia showed a significant nadph-d reaction. multiunit recording of neuromast afferent activity was also performed. nitric oxide synthase inhibitor n omega-nitro-l-arginine methyl ester (l-name) produced an initial slight excitation followed by a significant inhibiti ... | 2006 | 16225991 |
| histamine (h3) receptors modulate the excitatory amino acid receptor response of the vestibular afferents. | although the effectiveness of histamine-related drugs in the treatment of peripheral and central vestibular disorders may be explained by their action on the vestibular nuclei, it has also been shown that antivertigo effects can take place at the peripheral level. in this work, we examined the actions of h3 histaminergic agonists and antagonists on the afferent neuron electrical discharge in the isolated inner ear of the axolotl. our results indicate that h3 antagonists such as thioperamide, clo ... | 2005 | 16310756 |
| cranial neural crest emergence and migration in the mexican axolotl (ambystoma mexicanum). | the timing and pattern of cranial neural crest cell emergence and migration in the mexican axolotl, ambystoma mexicanum, are assessed using scanning electron microscopy (sem). cranial neural crest cells emerge and begin to migrate at the time of neural fold closure and soon form three distinct streams. the most anterior (mandibular) stream emerges first, at the level of the mesencephalon. cells in this stream migrate rostroventrally around the optic vesicle. the second (hyoid) and third (branchi ... | 2002 | 16351868 |
| myoseptal architecture of sarcopterygian fishes and salamanders with special reference to ambystoma mexicanum. | during axial undulatory swimming in fishes and salamanders muscular forces are transmitted to the vertebral axis and to the tail. one of the major components of force transmission is the myoseptal system. the structure of this system is well known in actinopterygian fishes, but has never been addressed in sarcopterygian fishes or salamanders. in this study we describe the spatial arrangement and collagen fiber architecture of myosepta in latimeria, two dipnoans, and three salamanders in order to ... | 2003 | 16351889 |
| the development of the hindbrain afferent projections in the axolotl: evidence for timing as a specific mechanism of afferent fiber sorting. | the aim of this study is to reveal the timing and growth pattern of central octavolateral projection development in the mexican axolotl, ambystoma mexicanum. in this amphibian species the development of the inner ear occurs first, followed by mechanosensory lateral line organs, and finally by ampullary electroreceptors. several hypotheses have been proposed about how the development of peripheral organs, including differential projections of the ear, might relate to the development of central pr ... | 2005 | 16351978 |
| [myocardial regeneration in ambystoma mexicanum after surgical injury]. | ventricular resection of the heart of ambystoma mexicanum was performed and the type of tissue that restored the lesion and if it is by hypertrophy or hyperplasia of myocardium, were evaluated. masson's trichrome stain indicated that 5 days after resection, the gap was occupied with a blood clot surrounded by collagen fibres (83 +/- 6%) and muscle (10 +/- 3%) and the rest of area (7 +/- 2%) free of tissue. a proportion of 50 +/- 4 and 90 +/- 2% was muscular tissue, 10 and 30 days after injury. t ... | 2006 | 16366167 |
| a germline gfp transgenic axolotl and its use to track cell fate: dual origin of the fin mesenchyme during development and the fate of blood cells during regeneration. | the development of transgenesis in axolotls is crucial for studying development and regeneration as it would allow for long-term cell fate tracing as well as gene expression analysis. we demonstrate here that plasmid injection into the one-cell stage axolotl embryo generates mosaic transgenic animals that display germline transmission of the transgene. the inclusion of scei meganuclease in the injections (thermes, v., grabher, c., ristoratore, f., bourrat, f., choulika, a., wittbrodt, j., joly, ... | 2006 | 16387293 |
| developmental and evolutionary origins of the vertebrate dentition: molecular controls for spatio-temporal organisation of tooth sites in osteichthyans. | the rainbow trout (oncorhynchus mykiss) as a developmental model surpasses both zebrafish and mouse for a more widespread distribution of teeth in the oro-pharynx as the basis for general vertebrate odontogenesis, one in which replacement is an essential requirement. studies on the rainbow trout have led to the identification of the initial sequential appearance of teeth, through differential gene expression as a changing spatio-temporal pattern, to set in place the primary teeth of the first ge ... | 2006 | 16496402 |
| crystal structure of axolotl (ambystoma mexicanum) liver bile acid-binding protein bound to cholic and oleic acid. | the family of the liver bile acid-binding proteins (l-babps), formerly called liver basic fatty acid-binding proteins (lb-fabps) shares fold and sequence similarity with the paralogous liver fatty acid-binding proteins (l-fabps) but has a different stoichiometry and specificity of ligand binding. this article describes the first x-ray structure of a member of the l-babp family, axolotl (ambystoma mexicanum) l-babp, bound to two different ligands: cholic and oleic acid. the protein binds one mole ... | 2006 | 16555310 |
| developmental analysis of genetic differences in pigmentation in the axolotl. | 1949 | 16588892 | |
| the rare occurrence of mitosis without spindle apparatus ("colchicine mitosis") producing endopolyploidy in embryos of the axolotl. | 1952 | 16589227 | |
| conjecture: can continuous regeneration lead to immortality? studies in the mrl mouse. | a particular mouse strain, the mrl mouse, has been shown to have unique healing properties that show normal replacement of tissue without scarring. the serendipitous discovery that the mrl mouse has a profound capacity for regeneration in some ways rivaling the classic newt and axolotl species raises the possibility that humans, too, may have an innate regenerative ability. we propose this mouse as a model for continuous regeneration with possible life-extending properties. we will use the class ... | 2006 | 16608389 |
| surface contraction and expansion waves correlated with differentiation in axolotl embryos--i. prolegomenon and differentiation during invagination through the blastopore, as shown by the fate map. | we have discovered a series of expansion and contraction, solitary waves that correlate with discrete steps of differentiation in the urodele amphibian axolotl embryo (ambystoma mexicanum). here we examine in detail the proposition that the blastopore is a set of differentiation waves. we superimposed the image of the axolotl fate map onto our digitized video images of normal gastrulation and matched the fate map to pigmentation irregularities on the embryo. we were then able to track the invagi ... | 1994 | 16649266 |
| conserved roles for oct4 homologues in maintaining multipotency during early vertebrate development. | all vertebrate embryos have multipotent cells until gastrulation but, to date, derivation of embryonic stem (es) cell lines has been achieved only for mouse and primates. es cells are derived from mammalian inner cell mass (icm) tissue that express the class v pou domain (pouv) protein oct4. loss of oct4 in mice results in a failure to maintain icm and consequently an inability to derive es cells. here, we show that oct4 homologues also function in early amphibian development where they act as s ... | 2006 | 16651543 |
| identification of the non-specific cytotoxic cell receptor protein 1 (nccrp1) in regenerating axolotl limbs. | the teleost non-specific cytotoxic cells (ncc) are evolutionary precursors of the mammalian natural killer (nk) cells and an important element of innate immunity. the non-specific cytotoxic cell receptor protein (nccrp1) is a characteristic cell surface protein with main functions in target cell recognition and cytotoxicity with sequence information available for many species of fish. we have isolated a cdna encoding the axolotl homologue of fish nccrp1 out of limb regeneration blastema and anal ... | 2006 | 16676190 |
| differential expression of tropomyosin during segmental heart development in mexican axolotl. | the mexican axolotl, ambystoma mexicanum, serves as an intriguing model to investigate myofibril organization and heart development in vertebrates. the axolotl has a homozygous recessive cardiac lethal gene "c" which causes a failure of ventricular myofibril formation and contraction. however, the conus of the heart beats, and has organized myofibrils. tropomyosin (tm), an essential component of the thin filament, has three known striated muscle isoforms (tpm1alpha, tpm1kappa, and tpm4alpha) in ... | 2006 | 16741969 |
| the rise of the boy-genius: psychological neoteny, science and modern life. | the mid-20th century saw the rise of the boy-genius, probably because a personality type characterized by prolonged youthfulness is advantageous both in science and modern life generally. this is the evolution of 'psychological neoteny', in which ever-more people retain for ever-longer the characteristic behaviours and attitudes of earlier developmental stages. whereas traditional societies are characterized by initiation ceremonies marking the advent of adulthood, these have now dwindled and di ... | 2006 | 16750307 |
| terminal nerve-derived neuropeptide y modulates physiological responses in the olfactory epithelium of hungry axolotls (ambystoma mexicanum). | the vertebrate brain actively regulates incoming sensory information, effectively filtering input and focusing attention toward environmental stimuli that are most relevant to the animal's behavioral context or physiological state. such centrifugal modulation has been shown to play an important role in processing in the retina and cochlea, but has received relatively little attention in olfaction. the terminal nerve, a cranial nerve that extends underneath the lamina propria surrounding the olfa ... | 2006 | 16855098 |
| molecular and immunohistochemical analyses of cardiac troponin t during cardiac development in the mexican axolotl, ambystoma mexicanum. | the mexican axolotl, ambystoma mexicanum, is an excellent animal model for studying heart development because it carries a naturally occurring recessive genetic mutation, designated gene c, for cardiac nonfunction. the double recessive mutants (c/c) fail to form organized myofibrils in the cardiac myoblasts resulting in hearts that fail to beat. tropomyosin expression patterns have been studied in detail and show dramatically decreased expression in the hearts of homozygous mutant embryos. becau ... | 2007 | 16888779 |
| the axolotl limb: a model for bone development, regeneration and fracture healing. | among vertebrates, urodele amphibians (e.g., axolotls) have the unique ability to perfectly regenerate complex body parts after amputation. the limb has been the most widely studied due to the presence of three defined axes and its ease of manipulation. hence, the limb has been chosen as a model to study the process of skeletogenesis during axolotl development, regeneration and to analyze this animal's ability to heal bone fractures. extensive studies have allowed researchers to gain some knowle ... | 2007 | 16920050 |
| 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 |
| 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 |
| changes in oxygen consumption during metamorphosis induced by thyroid administration in the axolotl. | 1927 | 16993919 | |
| 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 |
| 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 |
| [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 |
| 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 |
| 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 |
| curious dropsical condition of an axolotl. | 1887 | 17231716 | |
| 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 |
| 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 |
| mapping centromeres in the axolotl. | 1956 | 17247612 | |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| an infectious disease causing wide-spread necrosis in the liver of the mexican axolotl. | 1937 | 17732647 | |
| mutant genes in the mexican axolotl. | 1974 | 17756293 | |
| the mexican axolotl, and its susceptibility-to transformations. | 1885 | 17808850 | |
| the mexican axolotl and its susceptibility to transformations. | 1885 | 17837280 | |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 | |
| the influence of the corticotropic hormone from ox on the active salt uptake in the axolotl. | 1949 | 18129272 | |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| all about axolotls. | 2008 | 18356918 | |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |