| reconstitution of the central nervous system during salamander tail regeneration from the implanted neurospheres. | urodele amphibians such as axolotl are well known for their regenerative potential of the damaged central nervous system structures. upon tail amputation, neural stem cells behind the amputation plane undergo self-renewing divisions and contribute to the functional spinal cord in the newly formed regenerate. the neural stem cells, harboring this potential, can be isolated from the animal and cultured under the suspension conditions. after 2-3 weeks in vitro they will proliferate and form the flo ... | 2012 | 22914942 |
| retrotransposon long interspersed nucleotide element-1 (line-1) is activated during salamander limb regeneration. | salamanders possess an extraordinary capacity for tissue and organ regeneration when compared to mammals. in our effort to characterize the unique transcriptional fingerprint emerging during the early phase of salamander limb regeneration, we identified transcriptional activation of some germline-specific genes within the mexican axolotl (ambystoma mexicanum) that is indicative of cellular reprogramming of differentiated cells into a germline-like state. in this work, we focus on one of these ge ... | 2012 | 22913491 |
| activation of germline-specific genes is required for limb regeneration in the mexican axolotl. | the capacity for tissue and organ regeneration in humans is dwarfed by comparison to that of salamanders. emerging evidence suggests that mechanisms learned from the early phase of salamander limb regeneration-wound healing, cellular dedifferentiation and blastemal formation-will reveal therapeutic approaches for tissue regeneration in humans. here we describe a unique transcriptional fingerprint of regenerating limb tissue in the mexican axolotl (ambystoma mexicanum) that is indicative of cellu ... | 2012 | 22841627 |
| spatiotemporal regulation of keratin 5 and 17 in the axolotl limb. | amphibians have greater regeneration capability than higher vertebrates. they can regenerate their limbs after an amputation. as a limb is regenerated, a regeneration-specific epithelium called the apical epithelial cap (aec) is induced. the aec is an essential structure for limb regeneration. despite the importance of the aec, molecular marker genes have not been well studied at the molecular level. | 2012 | 22836940 |
| reconstitution of the central and peripheral nervous system during salamander tail regeneration. | we show that after tail amputation in ambystoma mexicanum (axolotl) the correct number and spacing of dorsal root ganglia are regenerated. by transplantation of spinal cord tissue and nonclonal neurospheres, we show that the central spinal cord represents a source of peripheral nervous system cells. interestingly, melanophores migrate from preexisting precursors in the skin. finally, we demonstrate that implantation of a clonally derived spinal cord neurosphere can result in reconstitution of al ... | 2012 | 22829665 |
| structural and functional analysis of intra-articular interzone tissue in axolotl salamanders. | knowledge of mechanisms directing diarthrodial joint development may be useful in understanding joint pathologies and identifying new therapies. we have previously established that axolotl salamanders can fully repair large articular cartilage lesions, which may be due to the presence of an interzone-like tissue in the intra-articular space. study objectives were to further characterize axolotl diarthrodial joint structure and determine the differentiation potential of interzone-like tissue in a ... | 2012 | 22800772 |
| visualization of retinoic acid signaling in transgenic axolotls during limb development and regeneration. | retinoic acid (ra) plays a necessary role in limb development and regeneration, but the precise mechanism by which it acts during these processes is unclear. the role of ra in limb regeneration was first highlighted by the remarkable effect that it has on respecifying the proximodistal axis of the regenerating limb so that serially repeated limbs are produced. to facilitate the study of ra signaling during development and then during regeneration of the same structure we have turned to the axolo ... | 2012 | 22627291 |
| nerve signaling regulates basal keratinocyte proliferation in the blastema apical epithelial cap in the axolotl (ambystoma mexicanum). | the ability of adult vertebrates to repair tissue damage is widespread and impressive; however, the ability to regenerate structurally complex organs such as the limb is limited largely to the salamanders. the fact that most of the tissues of the limb can regenerate has led investigators to question and identify the barriers to organ regeneration. from studies in the salamander, it is known that one of the earliest steps required for successful regeneration involves signaling between nerves and ... | 2012 | 22537500 |
| partial characterization of the sox2+ cell population in an adult murine model of digit amputation. | tissue regeneration in response to injury in adult mammals is generally limited to select tissues. nonmammalian species such as newts and axolotls undergo regeneration of complex tissues such as limbs and digits via recruitment and accumulation of local and circulating multipotent progenitors preprogrammed to recapitulate the missing tissue. directed recruitment and activation of progenitor cells at a site of injury in adult mammals may alter the default wound-healing response from scar tissue t ... | 2012 | 22530556 |
| muscle development and differentiation in the urodele ambystoma mexicanum. | muscle differentiation has been widely described in zebrafish and xenopus, but nothing is known about this process in amphibian urodeles. both anatomical features and locomotor activity in urodeles are known to show intermediate features between fish and anurans. therefore, a better understanding of myogenesis in urodeles could be useful to clarify the evolutionary changes that led to the formation of skeletal muscle in the trunk of land vertebrates. we report here a detailed morphological and m ... | 2012 | 22519643 |
| skin regeneration in adult axolotls: a blueprint for scar-free healing in vertebrates. | while considerable progress has been made towards understanding the complex processes and pathways that regulate human wound healing, regenerative medicine has been unable to develop therapies that coax the natural wound environment to heal scar-free. the inability to induce perfect skin regeneration stems partly from our limited understanding of how scar-free healing occurs in a natural setting. here we have investigated the wound repair process in adult axolotls and demonstrate that they are c ... | 2012 | 22485136 |
| semi-quantitative immunohistochemical detection of 5-hydroxymethyl-cytosine reveals conservation of its tissue distribution between amphibians and mammals. | 5-hydroxymethyl-cytosine (5-hmc) is a form of modified cytosine, which has recently attracted a considerable attention due to its potential role in transcriptional regulation. according to several reports 5-hydroxymethyl-cytosine distribution is tissue-specific in mammals. thus, 5-hmc is enriched in embryonic cell populations and in adult neuronal tissue. here, we describe a novel method of semi-quantitative immunohistochemical detection of 5-hmc and utilize it to assess the levels of this modif ... | 2012 | 22395462 |
| cell movements of the deep layer of non-neural ectoderm underlie complete neural tube closure in xenopus. | in developing vertebrates, the neural tube forms from a sheet of neural ectoderm by complex cell movements and morphogenesis. convergent extension movements and the apical constriction along with apical-basal elongation of cells in the neural ectoderm are thought to be essential for the neural tube closure (ntc) process. in addition, it is known that non-neural ectoderm also plays a crucial role in this process, as the neural tube fails to close in the absence of this tissue in chick and axolotl ... | 2012 | 22378637 |
| elaphoidella grandidieri (harpacticoida: copepoda): demographic characteristics and possible use as live prey in aquaculture. | in freshwater ecosystems, rotifers and cladocerans are ideal prey for fish larvae whereas copepods, due to their purported low growth rate and predatory tendency, are not. we recently isolated the parthenogenetic elaphoidella grandidieri (gueme et richard, 1893) a benthic freshwater harpacticoid, from a fish farm in the state of morelos, central mexico and tested its potential as a live prey organism for larval vertebrates. population growth and life table demography experiments were conducted, ... | 2011 | 22315830 |
| the amazing, regenerating axolotl. | | 2012 | 22261883 |
| ambiguities in the relationship between gonadal steroids and reproduction in axolotls (ambystoma mexicanum). | axolotls (ambystoma mexicanum) are aquatic salamanders that are widely used in research. axolotls have been bred in laboratories for nearly 150 years, yet little is known about the basic biology of reproduction in these animals. we investigated the effects of changing day length, time of year, and food availability on levels of circulating estradiol and androgens in adult female and male axolotls, respectively. in addition, we examined the effects of these variables on the mass of ovaries, ovidu ... | 2012 | 22245262 |
| esterases activity in the axolotl ambystoma mexicanum exposed to chlorpyrifos and its implication to motor activity. | the axolotl ambystoma mexicanum is a neotenic salamander considered a good biological model due to its ability to regenerate limbs, tail, brain and heart cells. nevertheless, severe reduction of a. mexicanum wild populations in the lacustrine area of xochimilco, the natural habitat of the axolotl, could be related to several environmental pressures as the presence of organophosphate pesticides (opps), intensively applied in agricultural activities in xochimilco. thus the aim of this study was to ... | 2011 | 21996259 |
| electrosensory ampullary organs are derived from lateral line placodes in bony fishes. | electroreception is an ancient subdivision of the lateral line sensory system, found in all major vertebrate groups (though lost in frogs, amniotes and most ray-finned fishes). electroreception is mediated by 'hair cells' in ampullary organs, distributed in fields flanking lines of mechanosensory hair cell-containing neuromasts that detect local water movement. neuromasts, and afferent neurons for both neuromasts and ampullary organs, develop from lateral line placodes. although ampullary organs ... | 2011 | 21988912 |
| immersion and branchial/transcutaneous irrigation anaesthesia with alfaxalone in a mexican axolotl. | immersion anaesthetic techniques are commonly used in amphibian species. alfaxalone has been reported as an immersion anaesthetic in fish but not amphibians. | 2011 | 21988819 |
| molecular and biochemical characterization of the mexican axolotl cd3 (cd3ε and cd3γ/δ). | in mammals, the t-cell receptor (tcr) complex expressed on mature t-cells consists of α/β or γ/δ clonotypic heterodimers non-covalently associated with four invariant chains forming the cd3 complex (cd3γ, cd3δ, cd3ε and cd3ζ). the tcr is the unit implicated in the antigenic peptide recognition whereas the cd3 subunits present as three different dimers (δ-ε, γ-ε and ζ-ζ) in the receptor complex participate to the signal transduction and are indispensable for the expression of the tcr at the cell ... | 2011 | 21789595 |
| the cellular basis for animal regeneration. | the ability of animals to regenerate missing parts is a dramatic and poorly understood aspect of biology. the sources of new cells for these regenerative phenomena have been sought for decades. recent advances involving cell fate tracking in complex tissues have shed new light on the cellular underpinnings of regeneration in hydra, planarians, zebrafish, xenopus, and axolotl. planarians accomplish regeneration with use of adult pluripotent stem cells, whereas several vertebrates utilize a collec ... | 2011 | 21763617 |
| a system for culturing iris pigment epithelial cells to study lens regeneration in newt. | salamanders like newt and axolotl possess the ability to regenerate many of its lost body parts such as limbs, the tail with spinal cord, eye, brain, heart, the jaw¹. specifically, newts are unique for its lens regeneration capability. upon lens removal, ipe cells of the dorsal iris transdifferentiate to lens cells and eventually form a new lens in about a month²(,)³ . this property of regeneration is never exhibited by the ventral iris cells. the regeneration potential of the iris cells can be ... | 2011 | 21730940 |
| the meis homeoprotein regulates the axolotl prod 1 promoter during limb regeneration. | during limb regeneration in salamanders the blastemal cells give rise only to structures distal to the level of amputation. this proximodistal identity can be regulated by ectopic expression of meis homeoproteins or the three finger protein prod 1 which acts at the cell surface. it has been suggested that meis acts by regulating the transcription of prod 1. we have sequenced the axolotl prod 1 promoter and selected two candidate sites for binding meis homeoproteins. the sites were mutated in var ... | 2011 | 21684325 |
| gene expression profile of the regeneration epithelium during axolotl limb regeneration. | urodele amphibians are unique among adult vertebrates in their ability to regenerate missing limbs. the process of limb regeneration requires several key tissues including a regeneration-competent wound epidermis called the regeneration epithelium (re). we used microarray analysis to profile gene expression of the re in the axolotl, a mexican salamander. a list of 125 genes and expressed sequence tags (ests) showed a ≥1.5-fold expression in the re than in a wound epidermis covering a lateral cuf ... | 2011 | 21648017 |
| blastema induction in aneurogenic state and prrx-1 regulation by mmps and fgfs in ambystoma mexicanum limb regeneration. | urodele amphibians can regenerate amputated limbs. it has been considered that differentiated dermal tissues generate multipotent and undifferentiated cells called blastema cells during limb regeneration. in early phases of limb regeneration, blastema cells are induced by nerves and the apical epithelial cap (aec). we had previously investigated the role of neurotrophic factors in blastema or blastema-like formation consisting of prrx-1 positive cells. a new system suitable for investigating ear ... | 2011 | 21539833 |
| pathological features of olfactory neuroblastoma in an axolotl (ambystoma mexicanum). | a one-year-old, female mexican axolotl (ambystoma mexicanum) had a rough-surfaced, polypoid, pink tumor mass of approximately 10 mm in diameter in the oral cavity. histologically, the tumor extended from the ethmoturbinate region and into the oral cavity and had replaced some of the maxillary bone tissue. the tumor mass was composed of a lobular architecture of small round-shaped tumor cells with occasional flexner-wintersteiner-like rosette formation. there were no metastatic lesions in the oth ... | 2011 | 21519157 |
| the axolotl model for regeneration and aging research: a mini-review. | although regeneration of tissues occurs in all adult tetrapods, the ability to regenerate complex structures such as limbs is limited to urodeles (newts and salamanders). given that many of the biological processes and the signaling pathways that control these processes are highly conserved among all tetrapods, it is likely that humans have the potential to regenerate structures in the same way as salamanders. thus the remarkable regenerative abilities of salamanders demonstrate what we reasonab ... | 2011 | 21372551 |
| glycated and carbamylated albumin are more "nephrotoxic" than unmodified albumin in the amphibian kidney. | there is increasing evidence that proteins in tubular fluid are "nephrotoxic." in vivo it is difficult to study protein loading of tubular epithelial cells in isolation, i.e., without concomitant glomerular damage or changes of renal hemodynamics, etc. recently, a unique amphibian model has been described which takes advantage of the special anatomy of the amphibian kidney in which a subset of nephrons drains the peritoneal cavity (open nephrons) so that intraperitoneal injection of protein sele ... | 2011 | 21367923 |
| dynamic expression of two thrombospondins during axolotl limb regeneration. | the molecular processes underlying regeneration remain largely unknown. several potential factors have been elucidated by focusing on the regenerative function of genes originally identified in a developmental context. a complementary approach is to consider the roles of factors involved in wound healing. here we focus on the thrombospondins, a family of secreted extracellular matrix proteins that have been implicated in skin wound healing in mammals. we show that a subset of thrombospondins are ... | 2011 | 21360624 |
| evolution of the germ line-soma relationship in vertebrate embryos. | the germ line and soma together maintain genetic lineages from generation to generation: the germ line passes genetic information between generations; the soma is the vehicle for germ line transmission, and is shaped by natural selection. the germ line and somatic lineages arise simultaneously in early embryos, but how their development is related depends on how primordial germ cells (pgc) are specified. pgcs are specified by one of two means. epigenesis describes the induction of pgcs from plur ... | 2011 | 21228047 |
| evidence for an rna polymerization activity in axolotl and xenopus egg extracts. | we have previously reported a post-transcriptional rna amplification observed in vivo following injection of in vitro synthesized transcripts into axolotl oocytes, unfertilized (ufe) or fertilized eggs. to further characterize this phenomenon, low speed extracts (lse) from axolotl and xenopus ufe were prepared and tested in an rna polymerization assay. the major conclusions are: i) the amphibian extracts catalyze the incorporation of radioactive ribonucleotide in rnase but not dnase sensitive pr ... | 2010 | 21203452 |
| regulation of proximal-distal intercalation during limb regeneration in the axolotl (ambystoma mexicanum). | intercalation is the process whereby cells located at the boundary of a wound interact to stimulate proliferation and the restoration of the structures between the boundaries that were lost during wounding. thus, intercalation is widely considered to be the mechanism of regeneration. when a salamander limb is amputated, the entire cascade of regeneration events is activated, and the missing limb segments and their boundaries (joints) as well as the structures within each segment are regenerated. ... | 2010 | 21158757 |
| functional and structural regeneration in the axolotl heart (ambystoma mexicanum) after partial ventricular amputation. | "in the present study we evaluated the effect of partial ventricular amputation (pva) in the heart of the adult urodele amphibian (ambystoma mexicanum) in vivo on spontaneous heart contractile activity recorded in vitro in association to the structural recovery at one, five, 30 and 90 days after injury. one day after pva, ventricular-tension (vt) (16 ± 3%), atrium-tension (at) (46 ± 4%) and heart rate (hr) (58+10%) resulted lower in comparison to control hearts. on days five, 30 and 90 after dam ... | 2010 | 21147570 |
| matrix metalloproteinase expression during blastema formation in regeneration-competent versus regeneration-deficient amphibian limbs. | we used an antibody array to compare the protein expression of matrix metalloproteinases (mmps)-1, -2, -3, -8, -9, -10, and -13, as well as the tissue inhibitors of metalloproteinases (timps)-1, -2, and -4 during blastema formation in amputated hindlimbs of regeneration-competent wild-type axolotls and stage-54 xenopus, and regeneration-deficient short-toes axolotls and xenopus froglets. expression of mmp-9 and -2 was also compared by zymography. both short-toes and froglet failed to up-regulate ... | 2011 | 21128310 |
| from genes to neural tube defects (ntds): insights from multiscale computational modeling. | the morphogenetic movements, and the embryonic phenotypes they ultimately produce, are the consequence of a series of events that involve signaling pathways, cytoskeletal components, and cell- and tissue-level mechanical interactions. in order to better understand how these events work together in the context of amphibian neurulation, an existing multiscale computational model was augmented. geometric data for this finite element-based mechanical model were obtained from 3d surface reconstructio ... | 2010 | 21119766 |
| functional convergence of signalling by gpi-anchored and anchorless forms of a salamander protein implicated in limb regeneration. | the gpi-anchor is an established determinant of molecular localisation and various functional roles have been attributed to it. the newt gpi-anchored three-finger protein (tfp) prod1 is an important regulator of cell behaviour during limb regeneration, but it is unclear how it signals to the interior of the cell. prod1 was expressed by transfection in cultured newt limb cells and activated transcription and expression of matrix metalloproteinase 9 (mmp9) by a pathway involving ligand-independent ... | 2011 | 21118959 |
| intrinsic repair of full-thickness articular cartilage defects in the axolotl salamander. | the ability to fully regenerate lost limbs has made the axolotl salamander (ambystoma mexicanum) a valuable model for studies of tissue regeneration. the current experiments investigate the ability of these vertebrates to repair large articular cartilage defects and restore normal hyaline cartilage and joint structure independent of limb amputation. | 2011 | 21115129 |
| ex vivo generation of a functional and regenerative wound epithelium from axolotl (ambystoma mexicanum) skin. | urodele amphibians (salamanders) are unique among adult vertebrates in their ability to regenerate structurally complete and fully functional limbs. regeneration is a stepwise process that requires interactions between keratinocytes, nerves and fibroblasts. the formation of a wound epithelium covering the amputation site is an early and necessary event in the process but the molecular mechanisms that underlie the role of the wound epithelium in regeneration remain unclear. we have developed an e ... | 2010 | 20874715 |
| skin wound healing in axolotls: a scarless process. | urodele amphibians, such as the axolotl (ambystoma mexicanum), have the unique faculty among vertebrates to regenerate lost appendages (limbs and tail) and other body parts (apex of the heart, forebrain and jaw) after amputation. interestingly, axolotls never seem to form scar tissue at the site of amputation once regeneration is completed. before now, very few studies were directly focused on the description of the events happening during wound healing after a skin injury in salamanders. in thi ... | 2010 | 20718005 |
| expression of a novel tropomyosin isoform in axolotl heart and skeletal muscle. | tpm1kappa is an alternatively spliced isoform of the tpm1 gene whose specific role in cardiac development and disease is yet to be elucidated. although mrna studies have shown tpm1kappa expression in axolotl heart and skeletal muscle, it has not been quantified. also the presence of tpm1kappa protein in axolotl heart and skeletal muscle has not been demonstrated. in this study, we quantified tpm1kappa mrna expression in axolotl heart and skeletal muscle. using a newly developed tpm1kappa specifi ... | 2010 | 20564186 |
| ion imaging during axolotl tail regeneration in vivo. | several studies have reported that endogenous ion currents are involved in a wide range of biological processes from single cell and tissue behavior to regeneration. various methods are used to assess intracellular and local ion dynamics in biological systems, e.g., patch clamping and vibrating probes. here, we introduce an approach to detect ion kinetics in vivo using a noninvasive method that can electrophysiologically characterize an entire experimental tissue region or organism. ion-specific ... | 2010 | 20549718 |
| lessons from the mexican axolotl: amphibian limb regeneration and its impact on plastic surgery. | | 2010 | 20517075 |
| a comparative study of gland cells implicated in the nerve dependence of salamander limb regeneration. | limb regeneration in salamanders proceeds by formation of the blastema, a mound of proliferating mesenchymal cells surrounded by a wound epithelium. regeneration by the blastema depends on the presence of regenerating nerves and in earlier work it was shown that axons upregulate the expression of newt anterior gradient (nag) protein first in schwann cells of the nerve sheath and second in dermal glands underlying the wound epidermis. the expression of nag protein after plasmid electroporation wa ... | 2010 | 20456522 |
| tissue factor expression in newt iris coincides with thrombin activation and lens regeneration. | lens regeneration in adult salamanders occurs at the pupillary margin of the mid-dorsal iris where pigmented epithelial cells (pec) re-enter the cell cycle and transdifferentiate into lens. it is not understood how the injury caused by removal of the lens (lentectomy) in one location is linked to initiating the response in a different spatial location (dorsal iris) and to this particular sector. we propose that the blood provides a link between the localised coagulation and signal transduction p ... | 2017 | 20420902 |
| a method for the analysis of organophosphorus pesticide residues in mexican axolotl. | a method based on matrix solid-phase dispersion (mspd) was developed for quantitative extraction of three organophosphorus pesticides (opps) from the mexican axolotl, ambystoma mexicanum. the determination was carried out using high- performance liquid chromatography (hplc) with diode array spectrophotometric uv detection (dad). the mspd extraction with octadecylsilyl (c18) sorbent combined with a silica gel clean-up and acetonitrile elution was optimised for chlorpyrifos, fenthion and methyl pa ... | 2010 | 20390927 |
| resection of a large intra-abdominal tumor in the mexican axolotl: a case report. | this case report describes the surgical removal of an intra-abdominal tumor from a mexican axolotl (ambystoma mexicanum). the animal was admitted with left abdominal swelling that had increased over 4 months. | 2010 | 20210972 |
| multiple sequences and factors are involved in stability/degradation of awnt-1, awnt-5a and awnt-5b mrnas during axolotl development. | following fertilization in amphibian, early cleavage stages are maternally controlled at a post-transcriptional level before initiation of zygotic transcriptions at the mid blastula transition (mbt). we document the expression levels of the axolotl awnt-1, awnt-5a and awnt-5b genes as well as the adenylation states of their corresponding mrnas from the end of oogenesis until the tailbud stages. awnt-1/-5a rnas are stable until mbt then degraded before gastrulation. awnt-5b rnas are degraded at f ... | 2010 | 20151991 |
| dermal fibroblasts contribute to multiple tissues in the accessory limb model. | the accessory limb model has become an alternative model for performing investigations of limb regeneration in an amputated limb. in the accessory limb model, a complete patterned limb can be induced as a result of an interaction between the wound epithelium, a nerve and dermal fibroblasts in the skin. studies should therefore focus on examining these tissues. to date, however, a study of cellular contributions in the accessory limb model has not been reported. by using green fluorescent protein ... | 2010 | 20148925 |
| induction of metamorphosis in axolotls (ambystoma mexicanum). | | 2009 | 20147244 |
| axolotl (ambystoma mexicanum) limb and tail amputation. | | 2009 | 20147243 |
| grafting axolotl (ambystoma mexicanum) limb skin and cartilage from gfp+ donors to normal hosts. | | 2009 | 20147242 |
| axolotl (ambystoma mexicanum) embryonic transplantation methods. | | 2009 | 20147241 |
| generation of transgenic axolotls (ambystoma mexicanum). | | 2009 | 20147240 |
| axolotl (ambystoma mexicanum) in vitro fertilization. | | 2009 | 20147239 |
| ambystoma mexicanum, the axolotl: a versatile amphibian model for regeneration, development, and evolution studies. | | 2009 | 20147230 |
| molecular cloning and characterization of ligand- and species-specificity of amphibian estrogen receptors. | estrogens are essential for normal reproductive activity in both males and females as well as for ovarian differentiation during a critical developmental stage in most vertebrates. to understand the molecular mechanisms of estrogen action and to evaluate estrogen receptor ligand interactions in amphibians, we isolated cdnas encoding the estrogen receptors (eralpha and erbeta) from the japanese firebelly newt (cynops pyrrhogaster), tokyo salamander (hynobius tokyoensis), axolotl (ambystoma mexica ... | 2010 | 20064516 |
| proteomic analysis of blastema formation in regenerating axolotl limbs. | following amputation, urodele salamander limbs reprogram somatic cells to form a blastema that self-organizes into the missing limb parts to restore the structure and function of the limb. to help understand the molecular basis of blastema formation, we used quantitative label-free liquid chromatography-mass spectrometry/mass spectrometry (lc-ms/ms)-based methods to analyze changes in the proteome that occurred 1, 4 and 7 days post amputation (dpa) through the mid-tibia/fibula of axolotl hind li ... | 2009 | 19948009 |
| neurotrophic regulation of fibroblast dedifferentiation during limb skeletal regeneration in the axolotl (ambystoma mexicanum). | the ability of animals to repair tissue damage is widespread and impressive. among tissues, the repair and remodeling of bone occurs during growth and in response to injury; however, loss of bone above a threshold amount is not regenerated, resulting in a "critical-size defect" (csd). the development of therapies to replace or regenerate a csd is a major focus of research in regenerative medicine and tissue engineering. adult urodeles (salamanders) are unique in their ability to regenerate compl ... | 2010 | 19944088 |
| coherent movement of cell layers during wound healing by image correlation spectroscopy. | we have determined the complex sequence of events from the point of injury until reepithelialization in axolotl skin explant model and shown that cell layers move coherently driven by cell swelling after injury. we quantified three-dimensional cell migration using correlation spectroscopy and resolved complex dynamics such as the formation of dislocation points and concerted cell motion. we quantified relative behavior such as velocities and swelling of cells as a function of cell layer during h ... | 2009 | 19804742 |
| sciatic nerve injury model in the axolotl: functional, electrophysiological, and radiographic outcomes. | the 2 aims of this study were as follows: 1) to establish outcome measures of nerve regeneration in an axolotl model of peripheral nerve injury; and 2) to define the timing and completeness of reinnervation in the axolotl following different types of sciatic nerve injury. | 2010 | 19764825 |
| detecting mitoses in time-lapse images of embryonic epithelia using intensity analysis. | although the frequency and orientation of mitoses can significantly affect the mechanics of early embryo development, these data have not been available due to a shortage of suitable automated techniques. fluorescence imaging, though popular, requires biochemical intervention and is not always possible or desirable. here, a new technique that takes advantage of a localized intensity change that occurs in bright field images is used to identify mitoses. the algorithm involves mapping a deformable ... | 2009 | 19757061 |
| myofibril-inducing rna (mir) is essential for tropomyosin expression and myofibrillogenesis in axolotl hearts. | the mexican axolotl, ambystoma mexicanum, carries the naturally-occurring recessive mutant gene 'c' that results in a failure of homozygous (c/c) embryos to form hearts that beat because of an absence of organized myofibrils. our previous studies have shown that a noncoding rna, myofibril-inducing rna (mir), is capable of promoting myofibrillogenesis and heart beating in the mutant (c/c) axolotls. the present study demonstrates that the mir gene is essential for tropomyosin (tm) expression in ax ... | 2009 | 19728883 |
| mir-196 is an essential early-stage regulator of tail regeneration, upstream of key spinal cord patterning events. | salamanders have the remarkable ability to regenerate many body parts following catastrophic injuries, including a fully functional spinal cord following a tail amputation. the molecular basis for how this process is so exquisitely well-regulated, assuring a faithful replication of missing structures every time, remains poorly understood. therefore a study of microrna expression and function during regeneration in the axolotl, ambystoma mexicanum, was undertaken. using microarray-based profiling ... | 2009 | 19682983 |
| memory of fate and position, colorized. | many of our ideas about cellular memory of fate and position come from regeneration studies in salamanders. a popular notion is that cells of the blastema transdifferentiate to different fates during limb regeneration. in a recent issue of nature, tanaka and colleagues challenge this notion. using transplant experiments with gfp-expressing axolotl, they show vividly which cells of the blastema remember their fate and position of origin. | 2009 | 19619486 |
| the role of nerve signaling in limb genesis and agenesis during axolotl limb regeneration. | | 2009 | 19571075 |
| cells keep a memory of their tissue origin during axolotl limb regeneration. | during limb regeneration adult tissue is converted into a zone of undifferentiated progenitors called the blastema that reforms the diverse tissues of the limb. previous experiments have led to wide acceptance that limb tissues dedifferentiate to form pluripotent cells. here we have reexamined this question using an integrated gfp transgene to track the major limb tissues during limb regeneration in the salamander ambystoma mexicanum (the axolotl). surprisingly, we find that each tissue produces ... | 2009 | 19571878 |
| regeneration and pattern formation - an interview with susan bryant. interviewed by richardson, michael k and chuong, cheng-ming. | susan bryant is one of the leading researchers in regeneration and pattern formation. born in england in 1943, she studied biology at kings college, london (uk). after a ph.d. with angus bellairs on caudal autotomy and regeneration in lizards, she researched urodele regeneration in marcus singer's lab at case western reserve university. then, at the university of california, irvine, she adopted the axolotl as a research model for limb regeneration and pattern formation. her work supported models ... | 2009 | 19557688 |
| epigenetic marks in somatic chromatin are remodelled to resemble pluripotent nuclei by amphibian oocyte extracts. | reprogramming pluripotency after nuclear transplantation shows that molecules in oocytes can remodel somatic chromatin to a stem cell state. here we report on an ex-ovo system using axolotl oocyte extracts to remodel epigenetic marks of somatic chromatin. molecules present in axolotl oocyte extracts induce the reduction of the overall levels of h3k9me3, hp1alpha and dna methylation of somatic cells, and they increase the levels of h3k9ac. the levels of signal intensity detected in treated differ ... | 2009 | 19440040 |
| a model of transcriptional and morphological changes during thyroid hormone-induced metamorphosis of the axolotl. | anuran (frog) metamorphosis has long-served as a model of how thyroid hormones regulate post-embryonic development in vertebrates. however, comparatively little is known about urodele (salamander) metamorphosis. we conducted a detailed time-course study of induced metamorphosis in the mexican axolotl (ambystoma mexicanum) that probed metamorphic changes in morphology and gene expression in the skin. using morphometrics, quantitative pcr, histology, and in situ hybridization we demonstrate that t ... | 2009 | 19275901 |
| expression of nkx2.5 in wild type, cardiac mutant, and thyroxine-induced metamorphosed hearts of the mexican axolotl. | nkx2.5, a homeodomain-containing transcription factor, is known to be necessary for normal heart development in vertebrates. it is one of the earliest lineage-restricted genes expressed in cardiovascular progenitor cells and knowledge of its expression patterns has important therapeutic implications for damaged cardiomyocytes. mexican axolotl is a unique system to study heart development for two reasons: the presence of a mutant phenotype lacking organized myofibrils due to sarcomeric tropomyosi ... | 2009 | 19191032 |
| cardiovascular physiology and diseases of amphibians. | the class amphibia includes three orders of amphibians: the anurans (frogs and toads), urodeles (salamanders, axolotls, and newts), and caecilians. the diversity of lifestyles across these three orders has accompanying differences in the cardiovascular anatomy and physiology allowing for adaptations to aquatic or terrestrial habitats, pulmonic or gill respiration, hibernation, and body elongation (in the caecilian). this article provides a review of amphibian cardiovascular anatomy and physiolog ... | 2009 | 19131029 |
| detection of mitoses in embryonic epithelia using motion field analysis. | although computer simulations indicate that mitosis may be important to the mechanics of morphogenetic movements, algorithms to identify mitoses in bright field images of embryonic epithelia have not previously been available. here, the authors present an algorithm that identifies mitoses and their orientations based on the motion field between successive images. within this motion field, the algorithm seeks 'mitosis motion field prototypes' characterised by convergent motion in one direction an ... | 2009 | 19051076 |
| regulation of dermal fibroblast dedifferentiation and redifferentiation during wound healing and limb regeneration in the axolotl. | adult urodeles (salamanders) are unique in their ability to regenerate complex organs perfectly. the accessory limb model (alm) in the axolotl allows for the identification of signals from the wound epidermis, nerves and dermal fibroblasts that interact to regenerate a limb. in the present study, we have used the alm to identity the axolotl (ambystoma mexicanum) orthologue of twist (amtwist), a basic helix-loop-helix transcription factor that is involved in the regeneration of the dermis during ... | 2008 | 19046162 |
| axolotl/newt. | | 2008 | 19030817 |
| organophosphorus pesticides effect on early stages of the axolotl ambystoma mexicanum (amphibia: caudata). | ambystoma mexicanum is an endemic salamander of xochimilco, a wetland of the basin of mexico valley. nowadays, axolotl populations are decreasing due environmental stressors. particularly, studies about organophosphorus pesticides (opps; i.e. chlorpyrifos and malathion) toxicity are of great importance due to their intensive use in agricultural activities in xochimilco. thus, the aim of this study was to evaluate under controlled conditions the toxicity of chlorpyrifos (cpf) and malathion (mlt) ... | 2009 | 19012946 |
| a comparative proteomic analysis during urodele lens regeneration. | to examine underlying mechanisms of urodele lens regeneration we have employed a proteomic analysis of 650 proteins involved in several signaling pathways. we compared expression of these proteins between the regeneration-competent dorsal iris and the regeneration-incompetent ventral iris in the newt. after a series of screenings we selected several proteins to evaluate their expression quantitatively on immunoblots. we then used these selected proteins to compare their expression between the do ... | 2008 | 18848527 |
| regeneration in axolotls: a model to aim for! | urodele amphibians such as the axolotl are the champions of tissue regeneration amongst vertebrates. these animals have mastered the ability to repair and replace most of their tissues following damage or amputation even well into adulthood. in fact it seems that the ability of these organisms to regenerate perfectly is not affected by their age. in addition to being able to regenerate, these animals display a remarkable resistance to cancer. they therefore represent a unique model organism to s ... | 2008 | 18814845 |
| dual epithelial origin of vertebrate oral teeth. | the oral cavity of vertebrates is generally thought to arise as an ectodermal invagination. consistent with this, oral teeth are proposed to arise exclusively from ectoderm, contributing to tooth enamel epithelium, and from neural crest derived mesenchyme, contributing to dentin and pulp. yet in many vertebrate groups, teeth are not restricted only to the oral cavity, but extend posteriorly as pharyngeal teeth that could be derived either directly from the endodermal epithelium, or from the ecto ... | 2008 | 18794902 |
| glucose transporter distribution in the vessels of the central nervous system of the axolotl ambystoma mexicanum (urodela: ambystomatidae). | the glut-1 isoform of the glucose transporter is commonly considered a reliable molecular marker of blood-brain barrier endothelia in the neural vasculature organized in a three-dimensional network of single vessels. the central nervous system of the axolotl ambystoma mexicanum is characterized by a vascular architecture that contains both single and paired vessels. the presence and distribution of the glut-1 transporter are studied in this urodele using both immunoperoxidase histochemistry and ... | 2008 | 18727107 |
| identification of differentially expressed genes in 4-day axolotl limb blastema by suppression subtractive hybridization. | the goal of our study was the identification of up-regulated genes during axolotl (ambystoma mexicanum) hindlimb regeneration 4 days after amputation using suppression subtractive hybridization (ssh). approximately 400 clones that harbored upregulated genes in regenerating blastema tissue were selected for sequence analysis. a blast homology search against ncbi non-redundant database and an ambystoma est database revealed 102 clones that showed homology to known sequences in genbank with annotat ... | 2008 | 18663994 |
| a novel protein involved in heart development in ambystoma mexicanum is localized in endoplasmic reticulum. | the discovery of the naturally occurring cardiac non-function (c) animal strain in ambystoma mexicanum (axolotl) provides a valuable animal model to study cardiomyocyte differentiation. in homozygous mutant animals (c/c), rhythmic contractions of the embryonic heart are absent due to a lack of organized myofibrils. we have previously cloned a partial sequence of a peptide cdna (n1) from an anterior-endoderm-conditioned-medium rna library that had been shown to be able to rescue the mutant phenot ... | 2008 | 18563628 |
| neurotrophic regulation of epidermal dedifferentiation during wound healing and limb regeneration in the axolotl (ambystoma mexicanum). | adult urodeles (salamanders) are unique in their ability to regenerate complex organs perfectly. the recently developed accessory limb model (alm) in the axolotl provides an opportunity to identify and characterize the essential signaling events that control the early steps in limb regeneration. the alm demonstrates that limb regeneration progresses in a stepwise fashion that is dependent on signals from the wound epidermis, nerves and dermal fibroblasts from opposite sides of the limb. when all ... | 2008 | 18533144 |
| effects of nitrate on embryos of three amphibian species. | embryos of three aquatic breeding amphibian species, ambystoma mexicanum, hyla chrysoscelis, and rana clamitans, were exposed to increasing levels (0, 5, 10, 30, 60, 100, 300, and 500 mg/l) of nitrate-n (no(3)-) in laboratory, static-renewal experiments. lethal effects were recorded from gosner stage 2 (h. chrysoscelis and r. clamitans) or harrison stage 2 (a. mexicanum) to time of hatching. date of hatching and length at hatching were also compared between treatments for a. mexicanum. no signif ... | 2008 | 18496633 |
| multi-scale finite element modeling allows the mechanics of amphibian neurulation to be elucidated. | the novel multi-scale computational approach introduced here makes possible a new means for testing hypotheses about the forces that drive specific morphogenetic movements. a 3d model based on this approach is used to investigate neurulation in the axolotl (ambystoma mexicanum), a type of amphibian. the model is based on geometric data from 3d surface reconstructions of live embryos and from serial sections. tissue properties are described by a system of cell-based constitutive equations, and pa ... | 2008 | 18408255 |
| orexin-a immunoreactive cells and fibers in the central nervous system of the axolotl brain and their association with tyrosine hydroxylase and serotonin immunoreactive somata. | orexin-a-like immunoreactivity in the axolotl brain was investigated by immunohistochemistry. immunoreactive somata formed a single group in the hypothalamus, but were distributed beyond several nuclei, namely, the ventral aspect of the nucleus preopticus posterior, dorsal aspect of the nucleus suprachiasmaticus and anterior aspect of the pars ventralis hypothalami. immunoreactive fibers were distributed throughout the brain from the olfactory bulb to the spinal cord except the cerebellum. the d ... | 2008 | 18378425 |
| all about axolotls. | | 2008 | 18356918 |
| analysis of the expression and function of wnt-5a and wnt-5b in developing and regenerating axolotl (ambystoma mexicanum) limbs. | urodele amphibians are unique adult vertebrates because they are able to regenerate body parts after amputation. studies of urodele limb regeneration, the key model system for vertebrate regeneration, have led to an understanding of the origin of blastema cells and the importance of positional interactions between blastema cells in the control of growth and pattern formation. progress is now being made in the identification of the signaling pathways that regulate dedifferentiation, blastema morp ... | 2008 | 18336582 |
| 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 |
| 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 |
| transforming growth factor: beta signaling is essential for limb regeneration in axolotls. | axolotls (urodele amphibians) have the unique ability, among vertebrates, to perfectly regenerate many parts of their body including limbs, tail, jaw and spinal cord following injury or amputation. the axolotl limb is the most widely used structure as an experimental model to study tissue regeneration. the process is well characterized, requiring multiple cellular and molecular mechanisms. the preparation phase represents the first part of the regeneration process which includes wound healing, c ... | 2007 | 18043735 |
| a clash of traditions: the history of comparative and experimental embryology in sweden as exemplified by the research of gösta jägersten and sven hörstadius. | until the 1940s research traditions were often imported from germany to sweden, and young scientists went to german universities to learn new techniques and get in touch with the latest ideas. in developmental biology, the comparative, phylogenetic embryology advocated most forcefully by ernst haeckel co-existed with the "entwickelungsmechanik" tradition developed by wilhelm his, wilheln roux and others partly as a reaction to haeckel's ideas. i use the zoology department at uppsala university a ... | 2007 | 18008099 |
| evidence for balancing selection at the dab locus in the axolotl, ambystoma mexicanum. | the axolotl (ambystoma mexicanum) has been characterized as immunodeficient, and the absence of major histocompatibility complex (mhc) class ii polymorphism has been cited as a possible explanation. here we present evidence for considerable allelic polymorphism at the mhc class ii dab locus for a sample of wild-caught axolotls. evidence that these sequences are the product of balancing selection for disease resistance is discussed. | 2007 | 18001306 |
| a reduction of tropomyosin limits development of sarcomeric structures in cardiac mutant hearts of the mexican axolotl. | the cardiac lethal mutation in mexican axolotl (ambystoma mexicanum) results in a lack of contractions in the ventricle of mutant embryos. previous studies have demonstrated that tropomyosin, a component of thin filaments, is greatly reduced in mutant hearts lacking myofibril organization. confocal microscopy was used to examine the structure and comparative amount of tropomyosin at heartbeat initiation and at a later stage. the formation of functional sarcomeres coincided with contractions in n ... | 2007 | 17990128 |
| muscular derivatives of the cranialmost somites revealed by long-term fate mapping in the mexican axolotl (ambystoma mexicanum). | the fate of single somites has not been analyzed from a comparative perspective with modern cell-marking methods. most of what we know is based on work using quail-chick chimeras. consequently, to what degree cell fate has been conserved despite the anatomical differences among vertebrates is unknown. we have analyzed the cell fate of the cranialmost somites, with the focus on somite two, in the mexican axolotl (ambystoma mexicanum). somite cells were marked by injection of dextran-fluorescein a ... | 2007 | 17976053 |
| nerve-induced ectopic limb blastemas in the axolotl are equivalent to amputation-induced blastemas. | adult urodeles (salamanders) are unique in their ability to regenerate complex organs perfectly. the recently developed accessory limb model (alm) in the axolotl provides an opportunity to identify and characterize the essential signaling events that control the early steps in limb regeneration. the alm demonstrates that limb regeneration progresses in a stepwise fashion that is dependent on signals from the wound epidermis, nerves and dermal fibroblasts from opposite sides of the limb. when all ... | 2007 | 17959163 |
| bone morphogenetic protein-4 and noggin signaling regulates pigment cell distribution in the axolotl trunk. | wild-type (dark) and white mutant axolotl (ambystoma mexicanum) embryos were used to investigate the role of the secreted growth factor bone morphogenetic protein-4 (bmp-4) and its antagonist, noggin, in dorso-lateral trunk neural crest (nc) migration. implantation of a bmp-4-coated microbead caused a melanophore-free zone around the bead, reduction of the dorsal fin above the bead, and disappearance of myotome tissue. we established a novel method that allows controlled induction of protein syn ... | 2008 | 17662068 |
| the short toes mutation of the axolotl. | the axolotl mutant strain, short toes (s/s), can regenerate spinal cord and tail, but not limbs. this makes s/s potentially very useful for limb regeneration studies. this mutant merits a new examination that integrates the original description of the mutant, existing experimental studies, new data and current thinking about stem cells and regeneration. there are still major gaps in information about this mutant; the gene(s) causing the defects has not yet been discovered, and even the histologi ... | 2007 | 17661741 |
| bmp-4 and noggin signaling modulate dorsal fin and somite development in the axolotl trunk. | bmp-4, a member of the tgf-beta superfamily of growth factors, is involved in various developmental processes. we investigated the effects of bmp-4 and its antagonist noggin on axolotl trunk development. implantation of bmp-4-coated microbeads caused inhibition of muscle and dorsal fin formation in the vicinity of the microbeads. at some distance, myotomes developed with reduced height but increased width, which was accompanied by increased cell proliferation. these effects could be modulated by ... | 2007 | 17654602 |
| highly restricted diversity of tcr delta chains of the amphibian mexican axolotl (ambystoma mexicanum) in peripheral tissues. | gammadelta t cells localize at mammalian epithelial surfaces to exert both protective and regulatory roles in response to infections. we have previously characterized the mexican axolotl (ambystoma mexicanum) t cell receptor delta (trd) chain. in this study, trd repertoires in spleen, liver, intestine and skin from larvae, pre-adult and adult axolotls were examined and compared to the thymic trd repertoire. a trdv transcript without n/d diversity, trdv1s1-trdj1, dominates the trd repertoires unt ... | 2007 | 17523213 |
| a clonal analysis of neural progenitors during axolotl spinal cord regeneration reveals evidence for both spatially restricted and multipotent progenitors. | complete regeneration of the spinal cord occurs after tail regeneration in urodele amphibians such as the axolotl. little is known about how neural progenitor cells are recruited from the mature tail, how they populate the regenerating spinal cord, and whether the neural progenitor cells are multipotent. to address these issues we used three types of cell fate mapping. by grafting green fluorescent protein-positive (gfp(+)) spinal cord we show that a 500 microm region adjacent to the amputation ... | 2007 | 17507409 |