Publications
| Title | Abstract | Year Filter | PMID(sorted descending) Filter |
|---|
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| the rare occurrence of mitosis without spindle apparatus ("colchicine mitosis") producing endopolyploidy in embryos of the axolotl. | 1952 | 16589227 | |
| developmental analysis of genetic differences in pigmentation in the axolotl. | 1949 | 16588892 | |
| 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 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 |
| 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 |
| [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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| biochemical gradients in the axolotl gastrula. | 1950 | 15444065 | |
| [isolated action of different hormones on the metamorphosis of hypophysectomized axolotls]. | 1950 | 15421580 | |
| [the inhibitory action of thiouracil on the melanogenesis of the regenerating tail of axolotl]. | 1950 | 15421315 | |
| 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 |
| 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 |
| from biomedicine to natural history research: est resources for ambystomatid salamanders. | establishing genomic resources for closely related species will provide comparative insights that are crucial for understanding diversity and variability at multiple levels of biological organization. we developed ests for mexican axolotl (ambystoma mexicanum) and eastern tiger salamander (a. tigrinum tigrinum), species with deep and diverse research histories. | 2004 | 15310388 |
| the scarless heart and the mrl mouse. | the ability to regenerate tissues and limbs in its most robust form is seen in many non-mammalian species. the serendipitous discovery that the mrl mouse has a profound capacity for regeneration in some ways rivalling the classic newt and axolotl species raises the possibility that humans, too, may have an innate regenerative ability. the adult mrl mouse regrows cartilage, skin, hair follicles and myocardium with near perfect fidelity and without scarring. this is seen in the ability to close th ... | 2004 | 15293806 |
| a critical role for thrombin in vertebrate lens regeneration. | lens regeneration in urodele amphibians such as the newt proceeds from the dorsal margin of the iris where pigment epithelial cells (pec) re-enter the cell cycle and transdifferentiate into lens. a general problem in regeneration research is to understand how the events of tissue injury or removal are coupled to the activation of plasticity in residual differentiated cells or stem cells. thrombin, a pivotal regulator of the injury response, has been implicated as a regulator of cell cycle re-ent ... | 2004 | 15293804 |
| characteristics of craniogenesis in the axolotl (ambystoma mexicanum: ambystomatidae) and the role of thyroid hormones in its regulation. | 2017 | 15255140 | |
| cell contact-dependent mechanisms specify taste bud pattern during a critical period early in embryonic development. | after gastrulation, the pharyngeal endoderm is specified to give rise to taste receptor organs without further signaling from other embryonic tissues. we hypothesized that intercellular signaling might be responsible for the specification of taste buds. to test if and when this signaling was occurring, intercellular contacts were transiently disrupted in cultures of pharyngeal endoderm from axolotl embryos, and the number, size, and distribution of taste buds analyzed. disruption of cell contact ... | 2004 | 15254897 |
| expression of a novel cardiac-specific tropomyosin isoform in humans. | tropomyosins are a family of actin binding proteins encoded by a group of highly conserved genes. humans have four tropomyosin-encoding genes: tpm1, tpm2, tpm3, and tpm4, each of which is known to generate multiple isoforms by alternative splicing, promoters, and 3' end processing. tpm1 is the most versatile and encodes a variety of tissue specific isoforms. the tpm1 isoform specific to striated muscle, designated tpm1alpha, consists of 10 exons: 1a, 2b, 3, 4, 5, 6b, 7, 8, and 9a/b. in this stud ... | 2004 | 15249230 |
| patterns of spatial and temporal visceral arch muscle development in the mexican axolotl (ambystoma mexicanum). | vertebrate head development is a classical topic that has received renewed attention during the last decade. most reports use one of a few model organisms (chicken, mouse, zebrafish) and have focused on molecular mechanisms and the role of the neural crest, while cranial muscle development has received less attention. here we describe cranial muscle differentiation and morphogenesis in the mexican axolotl, ambystoma mexicanum. to determine the onset of differentiation we use antibodies against d ... | 2004 | 15216519 |
| coupled amplification and degradation of exogenous rna injected in amphibian oocytes. | the early development of amphibians takes place in the absence of significant transcription and is controlled at the post-transcriptional level. we have reported that in vitro synthesized transcripts injected into axolotl fertilized eggs or oocytes were not continuously degraded as their abundance apparently fluctuated over time, with detected amounts sometimes higher than initial injected amounts. to further characterize this phenomenon, we have co-injected rna chain terminators to prevent rna ... | 2004 | 15161959 |
| low submetamorphic doses of dexamethasone and thyroxine induce complete metamorphosis in the axolotl (ambystoma mexicanum) when injected together. | entanglement of functions between the adrenal (or interrenal) and thyroid axis has been well described for all vertebrates and can be tracked down up to the level of gene expression. both thyroid hormones and corticosteroids may induce morphological changes leading to metamorphosis climax in the neotenic mexican axolotl (ambystoma mexicanum). in a first series of experiments, metamorphosis was induced with an injection of 25 microg t(4) on three alternate days as judged by a decrease in body wei ... | 2004 | 15158126 |
| early expression of two tdt isoforms in the hematopoietic system of the mexican axolotl. implications for the evolutionary origin of the n-nucleotide addition. | nontemplate (n)-nucleotide addition by the terminal dideoxynucleotidyl transferase (tdt) at the junctions of rearranging v( d) j gene segments greatly contribute to antigen-receptor diversity. tdt has been identified in several vertebrate species, where it is highly conserved. we report here the isolation of two forms of tdt mrna in an amphibian, the mexican axolotl. the isoform tdt1 shares all of the conserved structural motifs required for tdt activity and displays an average of 50-58% similar ... | 2004 | 15146297 |
| ultrastructure of the external gill epithelium of the axolotl, ambystoma mexicanum with reference to ionic transport. | the ultrastructure of the external gill epithelium of the axolotl, ambystoma mexicanum, has been examined using conventional transmission electron microscopy to elucidate its role in ionic transport. four cell types are identified in the gill filament and primary gill bar epithelium. these are granular, ciliated, leydig and basal cells. a fifth cell type, the flat mitochondria-rich cell is only found in the gill bar epithelium. the predominant granular cells display microvilli at their surface a ... | 2003 | 15137686 |
| the epithelia of the protrusible tongue of eurycea longicauda guttolineata (hoolbrook 1838) (urodela: plethodontidae). | in this study the lingual and sublingual glands, the lingual stem and the epithelial surface of the protrusible secondary tongue were investigated by light, scanning and transmission electron microscopy. the quality of the secretions of the epithelia was characterized histochemically. the lingual epithelium is formed by superficial (pavement) and goblet cells and at the margin of the tongue pad are also regions covered by ciliated cells. on the dorsal part of the tongue there are goblet cells of ... | 2003 | 15121544 |
| cloning and analysis of axolotl isl2 and lhx2 lim-homeodomain transcription factors. | we cloned and characterized the isl2 and lhx2 lim-homeodomain transcription factors of the mexican salamander, or axolotl, ambystoma mexicanum. using a degenerate pcr approach, partial cdnas representing five lim-homeodomain genes were cloned, indicating conservation of this class of transcription factors in urodeles. full-length cdnas for isl2 and lhx2 were identified and sequenced. the predicted isl2 and lhx2 proteins are well conserved, especially in the lim and dna-binding domains. the isl2 ... | 2004 | 15048808 |
| discrimination of conspecific sex and reproductive condition using chemical cues in axolotls ( ambystoma mexicanum). | chemosensory cues play an important role in the daily lives of salamanders, mediating foraging, conspecific recognition, and territorial advertising. we investigated the behavioral effects of conspecific whole-body odorants in axolotls, ambystoma mexicanum, a salamander species that is fully aquatic. we found that males increased general activity when exposed to female odorants, but that activity levels in females were not affected by conspecific odorants. although males showed no difference in ... | 2004 | 15034733 |
| activation of cdc2 kinase during meiotic maturation of axolotl oocyte. | activity of cdc2, the universal inducer of mitosis, is regulated by phosphorylation and binding to cyclin b. comparative studies using oocytes from several amphibian species have shown that different mechanisms allow cdc2 activation and entry into first meiotic division. in xenopus, immature oocytes stockpile pre-m-phase promoting factor (mpf) composed of cdc2-cyclin b complexes maintained inactive by thr14 and tyr15 phosphorylation of cdc2. activation of mpf relies on the conversion of pre-mpf ... | 2004 | 15013793 |
| retinoic acid repatterns axolotl lateral line receptors. | the effects of all-trans retinoic acid on the development of the lateral line placodes of axolotls was studied. late gastrula and early neurula were exposed to 10(-7) to 10(-5) m retinoic acid for one hour and then reared until they would normally be feeding larvae. as in other vertebrates, the extent of the developmental abnormalities is concentration dependent. those embryos exposed to the highest concentration of retinoic acid failed to form much of the forebrain and midbrain, including the o ... | 2004 | 15005576 |
| [specific growth rate and the rate of energy metabolism in the ontogenesis of axolotl, ambystoma mexicanum (amphibia: ambystomatidae)]. | concordant changes in the rate of energy metabolism and specific growth rate of axolotls have been revealed. several periods of ontogeny are distinguished, which differ in the ratio of energy metabolism to body weight and, therefore, are described by different allometric equations. it is suggested that the specific growth rate of an animal determines the type of dependence of energy metabolism on body weight. | 2016 | 14994475 |
| [developmental disorders of the vertebral column in axolotl in parts of the body deprived of the spinal cord]. | 1952 | 14936897 | |
| [role of the light in early stages of development of axolotl]. | 1952 | 14926635 | |
| influence of local x-ray treatment on development of jaws in young axolotl (siredon mexicanum). | 1952 | 14920442 | |
| [budding of erythrocytes of non-mammals in culture medium; positive culture of axolotl blood]. | 1951 | 14913009 | |
| [mechanism of the effect of the central nervous system on surrounding mesenchyma in foundation of axial skeleton in antogenesis in axolotl]. | 1952 | 14906247 | |
| [functional restoration of denervated extremity in axolotl following roentgen irradiation]. | 1951 | 14906191 | |
| [regeneration of roentgen irradiated axolotl extremity in implantation of non-specific tissue]. | 1951 | 14887583 | |
| [distribution of ribonucleic acid during extremity regeneration in the axolotl]. | 1951 | 14860074 | |
| [brunn reaction in axolotls]. | 1951 | 14859614 | |
| [investigations on the effect of certain iodinated and brominated aromatic compounds on metamorphosis in axolotl]. | 1951 | 14858374 | |
| [action of hormones in function of ph of milieu, on the metamorphosis and development of the axolotl (amblystoma tigrinum green); injections of raceme thyroxin and antuitrin s]. | 1951 | 14849071 | |
| [effect of the extract of the whole hypophysis combined with other hormones on the development of axolotl]. | 1951 | 14847255 | |
| [the neurohypophysis of the axolotl (amblystoma mexicanum)]. | 1951 | 14826989 | |
| [factors determining time, place, and type of development of the axial skeleton in axolotl]. | 1951 | 14793442 | |
| [similarity of correlations of the central nervous system with surrounding tissue in ontogenesis and in transplantation in the axolotl]. | 1951 | 14793425 | |
| injection of exogenous rna in amphibian oocytes leads to rna level fluctuations which are sensitive to cordycepin, an rna chain elongation terminator. | using an in vivo heterologous system to study the stability of xenopus laevis rna injected into axolotl (ambystoma mexicanum) fertilized eggs, we have previously observed unexpected fluctuations in rna level during early development [andéol et al., differentiation 63 (1998) 69-79]. in this study, we further characterize this phenomenon and establish its existence during axolotl and xenopus oogenesis, suggesting a phylogenetically conserved mechanism. the phenomenon can occur with a variety of ex ... | 2003 | 14746268 |
| combined intrinsic and extrinsic influences pattern cranial neural crest migration and pharyngeal arch morphogenesis in axolotl. | cranial neural crest cells migrate in a precisely segmented manner to form cranial ganglia, facial skeleton and other derivatives. here, we investigate the mechanisms underlying this patterning in the axolotl embryo using a combination of tissue culture, molecular markers, scanning electron microscopy and vital dye analysis. in vitro experiments reveal an intrinsic component to segmental migration; neural crest cells from the hindbrain segregate into distinct streams even in the absence of neigh ... | 2004 | 14738875 |
| downregulation of n1 gene expression inhibits the initial heartbeating and heart development in axolotls. | recessive mutant gene c in the axolotl results in a failure of affected embryos to develop contracting hearts. this abnormality can be corrected by treating the mutant heart with rna isolated from normal anterior endoderm or from endoderm conditioned medium. a cdna library was constructed from the total conditioned medium rna using a random priming technique in a pcdnaii vector. we have previously identified a clone (designated as n1) from the constructed axolotl cdna library, which has a unique ... | 2004 | 14729455 |
| identification of angiotensin i in several vertebrate species: its structural and functional evolution. | in order to delineate further the molecular evolution of the renin-angiotensin system in vertebrates, angiotensin i (ang i) has been isolated after incubation of plasma and kidney extracts of emu (dromiceus novaehollandiae), axolotl (ambystoma mexicanum), and sea lamprey (petromyzon marinus). the identified sequences were [asp1, val5, asn9] ang i in emu, [asp1, val5, his9] ang i in axolotl, and [asn1, val5, thr9] ang i in sea lamprey. these results confirmed the previous findings that tetrapods ... | 2004 | 14723880 |
| neurotrophin-independent attraction of growing sensory and motor axons towards developing xenopus limb buds in vitro. | the mechanisms for directing axons to their targets in developing limbs remain largely unknown though recent studies in mice have demonstrated the importance of neurotrophins in this process. we now report that in co-cultures of larval xenopus laevis limb buds with spinal cords and dorsal root ganglia of xenopus and axolotl (ambystoma mexicanum) axons grow directly to the limb buds over distances of up to 800 microm and in particular to sheets of epidermal cells which migrate away from the limb ... | 2004 | 14697361 |
| endogenous electric fields in embryos during development, regeneration and wound healing. | all embryos that have been investigated drive ionic currents through themselves and these currents will generate internal electric fields. here, those examples in which such fields have been measured directly are discussed. the first such measurements were made in chick embryos and about 20 mv mm(-1) was measured near the posterior intestinal portal in 2-4 day-old embryos. this electric field is important for the development of tail structures because reducing its magnitude results in abnormal t ... | 2003 | 14690282 |
| gustatory neurons derived from epibranchial placodes are attracted to, and trophically supported by, taste bud-bearing endoderm in vitro. | taste buds are multicellular receptor organs innervated by the viith, ixth, and xth cranial nerves. in most vertebrates, taste buds differentiate after nerve fibers have reached the lingual epithelium, suggesting that nerves induce taste buds. however, under experimental conditions, taste buds of amphibians develop independently of innervation. thus, rather than being induced by nerves, the developing taste periphery likely regulates ingrowing nerve fibers. to test this idea, we devised a cultur ... | 2003 | 14651931 |
| the axolotl (ambystoma mexicanum), a neotenic amphibian, expresses functional thyroid hormone receptors. | neotenic amphibians such as the axolotl (ambystoma mexicanum) are often unable to undergo metamorphosis under natural conditions. it is thought that neoteny represents a deviation from the standard course of amphibian ontogeny, affecting the thyroid axis at different levels from the central nervous system to peripheral organs. thyroid hormone receptors (trs) that bind the thyroid hormone (th) t(3) have been described in axolotl. however, the full sequences of tr were needed to better characteriz ... | 2004 | 14576183 |
| axolotl pronephric duct migration requires an epidermally derived, laminin 1-containing extracellular matrix and the integrin receptor alpha6beta1. | the epidermis overlying the migrating axolotl pronephric duct is known to participate in duct guidance. this epidermis deposits an extracellular matrix onto the migrating duct and its pathway that is a potential source of directional guidance cues. the role of this matrix in pronephric duct guidance was assayed by presenting matrix deposited on microcarriers directly to migrating pronephric ducts in situ. we found that reorientation of extracellular-matrix-bearing carriers prior to their present ... | 2003 | 14522870 |
| characterization of glycosaminoglycans during tooth development and mineralization in the axolotl, ambystoma mexicanum. | glycosaminoglycans (gags) involved in the formation of the teeth of ambystoma mexicanum were located and characterized with the cuprolinic blue (cb) staining method and transmission electron microscopy (tem). glycosaminoglycan-cuprolinic blue precipitates (gagcb) were found in different compartments of the mineralizing tissue. various populations of elongated gagcb could be discriminated both according to their size and their preferential distribution in the extracellular matrix (ecm). gagcb pop ... | 2003 | 14517102 |
| regulative germ cell specification in axolotl embryos: a primitive trait conserved in the mammalian lineage. | how germ cells are specified in the embryos of animals has been a mystery for decades. unlike most developmental processes, which are highly conserved, embryos specify germ cells in very different ways. curiously, in mouse embryos germ cells are specified by extracellular signals; they are not autonomously specified by maternal germ cell determinants (germ plasm), as are the germ cells in most animal model systems. we have developed the axolotl (ambystoma mexicanum), a salamander, as an experime ... | 2003 | 14511484 |
| [cytology of the islets of langerhans in the axolotl (siredon mexicanum) and ambyostoma maculatum]. | 1962 | 14455288 | |
| [regeneration of the extremities of the adult axolotl, at the expense of embryonal grafts]. | 1959 | 14414792 | |
| a maternal effect of a gene (f) for a fluid imbalance in the mexican axolotl. | 1960 | 14405375 | |
| [effect of isolated hormones on the development and experimental metamorphosis of the axolotl as a function of deficiency of the principal salts of the medum]. | 1954 | 14376947 | |
| [malignant neoplasms produced in axolotl with crystals of methylcholanthrene]. | 1954 | 14365611 | |
| [effect of isolated hormones on the experimental development and metamorphosis of the axolotl as a function of a deficiency of the main salts of the medium, potassium and sodium]. | 1954 | 14364939 | |
| the regulation of urea-biosynthesis enzymes in vertebrates. | 1. carbamoyl phosphate synthetase, ornithine transcarbamoylase, the arginine-synthetase system and arginase were measured in the livers of ammoniotelic, ureotelic and uricotelic animals. the chelonian reptiles, whose nitrogen excretory patterns vary according to the habitat, and the mexican axolotl, a neotenic species, were also studied. 2. the levels of the activities of the first three enzymes mentioned correlate with the amount of nitrogen excreted as urea. 3. the terrestrial turtle, which ex ... | 1965 | 14343146 |
| [study on the incorporation of s35-labeled sodium sulfate in the cartilage of the axolotl]. | 1965 | 14333227 | |
| [compensatory hyperplasia and regeneration in the telencephalon of ambystoma mexicanum following resection of a hemisphere]. | 1964 | 14332323 | |
| [influence of actinomycin d on the metamorphosis induced by thyroxine in the axolotl]. | 1965 | 14331244 |