| [effect of valinomycin on mitotic activity and ciliary movement during embryonic development]. | the k+ ionophore valinomycin very quickly arrests cleavage in sea urchin and mouse eggs at concentrations ranging between 10 and 3 micron. development of axolotl and xenopus eggs is not arrested before the blastula or gastrula stage. the motility of sea urchin sperm, blastulae and gastrulae is suppressed, within a few minutes, by 1-9 micron valinomycin. | 1978 | 96956 |
| delayed hypersensitivity in ambystoma mexicanum. | | 1979 | 113261 |
| [meiosis: role of a histone kinase in the condensation of ovarian oocyte chromosomes of xenopus laevis and ambystoma mexicanum]. | by injecting heterologous histone-kinase preparations into ovarian axolotl oocytes, it has been possible to speed up the progesterone-induced process of chromosome condensation. moreover, in some instances, this condensation and even complete maturation have been obtained after injection of protein kinase alone, thus in the absence of hormone stimulation. two different histone kinase preparations have been used: one was prepared from ascites cell chromatin and the other from in vitro ovulated xe ... | 1975 | 177222 |
| ketogenesis in vertebrate livers. | 1. the hypothesis is advanced that a gluconeogenic organ such as the liver would evolve to oxidise fatty acids as its source of atp for gluconeogenesis. it is also argued that such an organ might, in the light of current knowledge, be expected to be ketogenic. the animals investigated were lamprey, rainbow trout, eel, toad, axolotl, lizard and rat. 2. the respiratory quotients of liver slices from all animals was close to 0.74. ketone bodies were produced from butyrate by all livers excepting th ... | 1977 | 318434 |
| [participation of irradiated tissues in the formation of limb regenerates in axolotls]. | | 1976 | 939173 |
| [activity and isoenzymes of lactate dehydrogenase in tissues of amphibians (xenopus laevis, ambystoma mexicanum, triturus alpestris and vulgaris) and the response in the fat body of xenopus males to gonadotropin injection (author's transl)]. | lactate-dehydrogenase activity was determined by the optical test method using pyruvate as substrate and the isoenzymes were separated by vertical starch gel electrophoresis. species-specific and organ-specific characteristics of the total activity and the isoenzyme patterns of the four amphibian species are compared with those of rat and mouse. application of gonadotropin increases the amount of soluble protein and the lactate-dehydrogenase activity in the fat body of xenopus and the isoenzyme ... | 1975 | 1176091 |
| low resistance junctions between mesoderm cells during development of trunk muscles. | 1. electrical connexions between mesoderm cells have been examined during the formation of somites in xenopus laevis, bombina orientalis and ambystoma mexicanum. 2. in xenopus the resting potentials of presumptive myotome cells (-65 + 2 mv, s.e. of mean) and somite muscle cells (-65 +/- 0-6 mv s.e. of mean) were 40 mv, greater than dermatome cells (-25 +/- 0-6 mv, s.e. of mean). similar differences were found in bombina and ambystoma. 3. in all three species cells of the dermatome layer of the m ... | 1976 | 1255515 |
| neuron-specific enolase-like immunoreactivity in the vertebrate retina: selective labelling of müller cells in anura. | neuron-specific enolase (nse) immunocytochemistry was carried out in retinae of goldfish, axolotl, clawed frog, cane toad, lizard, chick, guinea-pig, rabbit, rat, cat and human. with the exception of anura, strong immunoreactivity was seen in the large ganglion, amacrine cells and horizontal cells of the retina in all of the other species. photoreceptors were found to be labelled in the rat and human retina and only one cone type in rabbit. photoreceptor pedicles and ellipsoids were stained in t ... | 1992 | 1459864 |
| phylogeny of the third component of complement, c3: analysis of the conservation of human cr1, cr2, h, and b binding sites, concanavalin a binding sites, and thiolester bond in the c3 from different species. | the third component of complement, c3, binds to several other complement proteins. to study the diverse reactivities of c3, we analyzed the conservation of structural and functional features in the c3 from different species. first, we developed a method to purify swine (po), rabbit (rb), mouse (mo), cobra (co), xenopus (xe), axolotl (ax), and trout (tr) c3 from plasma. this involved protein precipitation by polyethylene glycol, followed by anion-exchange, gel filtration, and cation exchange chro ... | 1992 | 1535601 |
| ectopic expression of a genomic fragment containing a homeobox causes neural defects in the axolotl. | an axolotl (ambystoma mexicanum) genomic fragment containing the ahox1 homeobox was placed under the control of the mouse hsp68 promoter, which seems to function constitutively in the axolotl. the resulting construct was injected into fertilized axolotl eggs to see if it would perturb development. of the injected embryos, 20% showed severe reduction of the anterior neural plate. later in development, these embryos had small heads, no eyes, and appeared to lack the normal regionalization of the b ... | 1991 | 1680349 |
| alkaline phosphatase and dipeptidylpeptidase iv staining of tissue components of skeletal muscle: a comparative study. | a combined alkaline phosphatase (ap) and dipeptidlypeptidase iv (dpp iv) staining reaction has demonstrated enzymatic heterogeneity of the arterial and venous segments of capillaries in rat skeletal muscle. this study compared the staining reactions of skeletal muscles in many commonly used laboratory animals, including the axolotl, chick, quail, monodelphys, rat, mouse, hamster, guinea pig, rabbit, dog, monkey, and human. dpp iv activity was found in the venous ends of the capillaries and in th ... | 1990 | 1701462 |
| localization of calmodulin in epidermis and skin glands: a comparative immunohistological investigation in different vertebrate species. | the study deals with the immunolocalization of calmodulin-reactive epithelial cells in different vertebrates (tinca tinca, ambystoma mexicanum, xenopus laevis, rana ridibunda, columba domestica, sus scrofa domestica, homo sapiens sapiens). the immunoperoxidase technique was performed on acetone fixed frozen sections using monoclonal (bf8) and polyclonal (acam) anti-calmodulin antibodies. we were able to differentiate 2 major types of staining patterns: 1. a more superficial epidermal staining in ... | 1991 | 1718122 |
| [adaptative differential maturation of neurohypophyseal provasotocin in amphibians: presence of hydrin 2(vasotocinyl-glycine) in anura but not in urodela]. | occurrence of hydrin 2 (vasotocinyl-glycine), an intermediate in the provasotocin processing, has been shown in the neurointermediate lobe of the pituitary of semi-aquatic or terrestrial amphibian species belonging to the order anura, namely rana esculenta, r. temporaria, r. pipiens (ranidae), and bufo bufo, b. marinus, b. ictericus (bufonidae). in contrast hydrin 2 appears absent in species belonging to the order urodela, namely the axolotl ambystoma mexicanum (ambystomidae) and the pleurodele ... | 1991 | 1756409 |
| hydrogen ion currents in rat alveolar epithelial cells. | alveolar epithelial cells isolated from rats and maintained in primary culture were studied using the whole-cell configuration of the "patch-clamp" technique. after other ionic conductances were eliminated by replacing permeant ions with n-methyl-d-glucamine methanesulfonate, large voltage-activated hydrogen-selective currents were observed. like h+ currents in snail neurons and axolotl oocytes, those in alveolar epithelium are activated by depolarization, deactivate upon repolarization, and are ... | 1991 | 1722118 |
| heterogeneity in spinal radial glia demonstrated by intermediate filament expression and hrp labelling. | considerable evidence indicates that radial glial cells play an active role in guiding growing neurites during development of the vertebrate cns. in this paper we describe subpopulations of radial glial in the spinal cord of the axolotl. amphibians maintain radial glia throughout life, and subpopulations are described using anatomical criteria following filling of individual cells with horseradish peroxidase and immunocytochemical staining with a range of intermediate filament antibodies. radial ... | 1990 | 1705577 |
| isolation and characterization of a developmentally regulated homeobox sequence in the mexican axolotl ambystoma mexicanum. | a homeobox-containing genomic dna fragment was isolated from the mexican axolotl. this clone was obtained from a partial genomic library enriched for sequences that cross-hybridized with the drosophila antp homeobox under low stringency hybridization conditions. dna sequence analysis revealed that this sequence (ahox1) was 66% homologous to the antp homeobox sequence and was most closely related to the mouse hox-1.6 (84% identity) and drosophila lab (79% identity) homeobox sequences. several cro ... | 1990 | 1695851 |
| mhc-like molecules in some nonmammalian vertebrates can be detected by some cross-reactive monoclonal antibodies. | mab to human and mouse mhc molecules were tested for binding to blood or spleen cells of various nonmammalian vertebrates by immunofluorescence and flow cytometry. those that bound were used to immunoprecipitate cross-reactive molecules from biosynthetically or cell surface-labeled spleen or blood cells. in addition, mab to human mhc molecules were screened by western blots. as expected from the results with xenoantisera, there were few mab that cross-reacted, and many of these cross-reactions w ... | 1990 | 1690241 |
| t-cell-specific membrane antigens in the mexican axolotl (urodele amphibian). | comparative analysis of sds-page patterns of axolotl spleen cells membrane detergent lysates showed important discrepancies between control and thymectomized animals. among these, a 38-kd protein band, which appeared as a major protein in controls, was not or poorly expressed after thymectomy. a rabbit antiserum (l12) raised against the 38-kd eluted band labeled in indirect immunofluorescence 80-86% of thymocytes and 40-46% of mig- lymphoid cells in the spleen. the anti-38-kd antibodies stained ... | 1992 | 1627952 |
| the stopping response of xenopus laevis embryos: behaviour, development and physiology. | 1. when xenopus laevis embryos swim into an obstruction they usually stop. this stopping response to stimulation on the head is present from stage 28 to 45. at stage 37/38 it is more reliable in restrained than in free-swimming animals, and to stimuli to the cement gland than to the head skin. 'fictive' swimming also stops reliably after the same stimuli but struggling and 'fictive' struggling do not. 2. discharge of deformation-sensitive trigeminal sensory neurons in response to pressure on the ... | 1992 | 1583603 |
| the marginal zone of the 32-cell amphibian embryo contains all the information required for chordamesoderm development. | the formation of the amphibian organizer is evidenced by the ability of cells of the dorsal marginal zone (dmz) to self-differentiate to form notochord and to induce the formation of other axial structures from neighboring regions of the embryo. we have attempted to determine when these abilities are acquired in the urodele, ambystoma mexicanum (axolotl), and in the anuran, xenopus laevis, by removing the mesodermalizing influence of the vegetal hemisphere at different stages of development and ... | 1992 | 1583451 |
| polymorphism of hyaluronidase in serum from man, various mouse strains and other vertebrate species revealed by electrophoresis. | polymorphism of hyaluronidase (ec 3.2.1.35) was detected in the serum from 6 out of 20 vertebrate species by electrophoretic analysis. electrophoresis was performed on a hyaluronan-containing polyacrylamide gel, that visualizes hyaluronidase activity upon incubation at acid ph. no hyaluronidase activity was detected in the sera of horse, swine, cattle, goat, sheep, rabbit, chicken, triton alpestris, triton palmatus, triton vulgaris, pleurodeles, axolotl, eel and dog-fish. the 6 positive sera wer ... | 1990 | 2357493 |
| reproducible proliferative responses of salamander (ambystoma mexicanum) lymphocytes cultured with mitogens in serum-free medium. | there are several reports that proliferative responses (tritiated thymidine incorporation (3htdr)) of salamander splenocytes cultured with phytohemagglutinin-p (pha) or concanavalin a (con a) in 1% fetal bovine serum (fbs)-supplemented medium are either statistically insignificant or never approach the magnitude typically observed in similarly treated cultures of frog lymphocytes. the present study confirms these findings, but also reports highly significant and reproducible pha-induced prolifer ... | 1992 | 1473594 |
| developmental expression of the xenopus int-2 (fgf-3) gene: activation by mesodermal and neural induction. | we have used a probe specific for the xenopus homologue of the mammalian proto-oncogene int-2 (fgf-3) to examine the temporal and spatial expression pattern of the gene during xenopus development. int-2 is expressed from just before the onset of gastrulation through to prelarval stages. in the early gastrula, it is expressed around the blastopore lip. this is maintained in the posterior third of the prospective mesoderm and neuroectoderm in the neurula. a second expression domain in the anterior ... | 1992 | 1425349 |
| isolation of lactose-binding lectins from axolotl (ambystoma mexicanum). | 1. lactose-inhibitable hemagglutination activity was identified in extracts of axolotl (ambystoma mexicanum) larvae. 2. two types of lectin were isolated from extracts by affinity chromatography on lactose-sepharose. 3. a thiol-independent lectin of subunit mol. wt 15 kda and a thiol-dependent lectin of subunit mol. wt 18 kda were identified. 4. the 15 kda and a 18 kda polypeptides were weakly reactive with polyclonal anti-human galaptin serum. | 1992 | 1424562 |
| evolution of vertebrate igm: complete amino acid sequence of the constant region of ambystoma mexicanum mu chain deduced from cdna sequence. | cdna clones coding for the constant region of the mexican axolotl (ambystoma mexicanum) mu heavy immunoglobulin chain were selected from total spleen rna, using a cdna polymerase chain reaction technique. the specific 5'-end primer was an oligonucleotide homologous to the jh segment of xenopus laevis mu chain. one of the clones, jha/3, corresponded to the complete constant region of the axolotl mu chain, consisting of a 1362-nucleotide sequence coding for a polypeptide of 454 amino acids followe ... | 1992 | 1382992 |
| immunohistochemical localization of beta-endorphin-like material in the urodele and anuran amphibian tissues. | in the present study, we have localized for the first time beta-endorphin (beta-ep)-like material in the adult and larval urodele and anuran tissues using immunohistochemical techniques. in the adult notophthalmus viridescens and ambystoma mexicanum, strong immunoreactivity to beta-ep antisera was observed in the region of the intermediate lobe, the latter fluorescing as a discrete body. the fluorescence was confined to the periphery of the cells, while the nuclei and the immediately surrounding ... | 1989 | 2530130 |
| valproic acid induced abnormal development of the central nervous system of three species of amphibians: implications for neural tube defects and alternative experimental systems. | embryos of ambystoma mexicanum, xenopus laevis, and hyperolius viridiflavus taeniatus were exposed to various concentrations of valproic acid (vpa: 0.1, 1.5, 10 mm) from blastula stage (s) 9 on up to advanced gastrulation of control embryos (s 11 1/2-12). at 10 and 5 mm vpa early development was affected in all species tested. however, the most pronounced effects occurred in ambystoma: the neural folds appeared delayed and showed a flattened and wavy shape; the neural tube was not formed and emb ... | 1992 | 1363963 |
| incorporation of labeled amino acids into proteins of the cell organelles of muscle tissue during the restoration of the regenerative capacity of the limbs of axolotl, suppressed by x-irradiation. | the incorporation of labeled amino acids into the total proteins of muscle tissue and cell organelles during the regeneration of limbs of axolotls and after the suppression of the regenerative capacity by x-irradiation and its experimental restoration were investigated. in the case of suppression of the regenerative capacity of the limbs by x-irradiation, the protein synthesis in the muscle tissue is impaired. the intensity of the incorporation of labeled amino acids into the proteins of a homog ... | 1975 | 1129636 |
| ontogeny of ldh-isozymes in mexican axolotl, ambystoma mexicanum by thin-layer isoelectric focusing. | the ontogeny of lactate dehydrogenase (ldh) isozymes in developing mexican axolotl, ambystoma mexicanum was investigated by thin-layer isoelectric focusing in polyacrylamide gel. the isoelectric points (pi values) of the isozymes were determined. the minor components generally remained masked during conventional electrophoresis, but became sharp as isofocusing progressed. we identified in developing eggs and embryos five major ldh isozymes, which could also be traced in the ovarian eggs. all the ... | 1976 | 992242 |
| antibody-dependent cellular cytotoxicity in poikilotherms. | 51cr-chromate labelled chicken red blood cells, treated with rabbit (anti-chicken red blood cell) serum, are lysed in vitro, in the absence of complement, by spleen cells from xenopus laevis, ambystoma mexicanum or lacerta viridis. optimal conditions for lysis by xenopus spleen cells were determined. the phenomenon seems homologous with antibody-dependent cellular cytotoxicity (adcc) mediated by mammalian or avian k cells. the phylogenetic significance of the finding is discussed. | 1977 | 612470 |
| a natural heterohaemagglutinin in xenopus laevis serum. | in most adult xenopus laevis the serum contains a 'natural' factor capable of lysing the erythrocytes from a wide variety of amniote species. the factor has no effect on the erythrocytes of another amphibian, ambystoma mexicanum, nor will serum from one animal lyse red cells from another xenopus individual. no lysing factor was present in the serum of larval (tadpole) xenopus. heating of xenopus serum to 56 degrees for 30 min, absorption of the serum with zymosan or inulin, or removal of calcium ... | 1978 | 580428 |
| role of tropomyosin in actin filament formation in embryonic salamander heart cells. | recessive mutant gene c in ambystoma mexicanum embryos causes a failure of the heart to function even though initial heart development appears normal. an analysis of the constituent proteins of normal and mutant hearts by sds-poly-acrylamide gel electrophoresis shows that actin (43,000 daltons) is present in almost normal amounts, while myosin heavy chain (200,000 daltons) is somewhat reduced in mutants. both sds-polyacrylamide gel electrophoresis and immunofluorescence studies reveal that tropo ... | 1979 | 383724 |
| binding of adrenergic ligands to liver plasma membrane preparations from the axolotl, ambystoma mexicanum; the toad, xenopus laevis; and the australian lungfish, neoceratodus forsteri. | the beta-adrenergic ligand iodocyanopindolol (icp) bound specifically to hepatic plasma membrane preparations from the axolotl, ambystoma mexicanum (bmax, 40 fmol/mg protein (p) at free concentration above 140 pm; kd, 42 pm); the toad, xenopus laevis (bmax, 200 fmol/mg p at 1 nm; kd, 300 pm); and the australian lungfish, neoceratodus forsteri (bmax, 100 fmol/mg p at 5 nm). for the lungfish, the scatchard plot was curved showing two classes of binding site with kd's of 20 and 500 pm. neither the ... | 1988 | 2847957 |
| thymus independent anti-horse erythrocyte antibody response and suppressor t cells in the mexican axolotl (amphibia, urodela, ambystoma mexicanum). | anti-horse erythrocyte (anti-hrbc) antibody synthesis was studied in normal, early thymectomized and adult thymectomized axolotls. the kinetics of the responses were similar to those described in the same species for antibody synthesis against bacterial or viral antigens. booster injections did not induce any characteristic anamnestic responses. early and adult thymectomized axoltls gave in three experimental groups higher anti-hrbc responses than controls. it is concluded that hrbc acts in the ... | 1979 | 312266 |
| [invariability of the h-y antigen expression in the heterogametic sex of some amphbians and evidence for sexual dimophrism of the antigen expression in pelodytes punctatus d (amphibia, anura)]. | the h-y antigen is studied in some amphibians whose sexual genetic constitution is known. thus, in pelurodeles waltlii, ambystoma mexicanum, xenopus laevis and rana ridibunda, the invariability of the h-y antigen expression in the heterogametic, sex is confirmed. in pelodytes punctatus the genetic sex is unknown but the existence of the h-y antigen in phenotypic males leads to the conclusion of a male heterogamety of the xy type. | 1979 | 121269 |
| [hormonal determination of the differentiation of striated skeletal muscle in urodele amphibians]. | in the urodelan amphibian pleurodeles waltlii, spontaneous external metamorphosis was correlated with an increase in the serum level of thyroxine (t4). within the same period, a change occurred in the myofibrillar atpase profile of the dorsal skeletal muscle; fibres of larval type were gradually replaced by transitional fibres (type iic), then by adult fibres of the types i, iia, and iib. likewise, a myosin isoenzymic transition was observed. in larval animals, myosin electrophoresis revealed 3 ... | 1988 | 2973102 |
| acidic fibroblast growth factor is present in regenerating limb blastemas of axolotls and binds specifically to blastema tissues. | the growth of regenerating limbs of amphibians depends upon proliferation of the blastema cells that accumulate beneath the epidermal cap. the epidermal cap is known to be mitogenic for the blastema cells. we have extracted a mitogenic activity from both the mesenchymal and epidermal (epidermal cap) components of cone stage blastemas which is retained on heparin-sepharose and elutes with 1.15 m nacl. this fraction stimulates neurite outgrowth of pc12 cells and [3h]thymidine incorporation into cc ... | 1991 | 2040374 |
| luteinizing hormone-releasing hormone induces thyroxine release together with testosterone in the neotenic axolotl ambystoma mexicanum. | in male neotenic axolotls ambystoma mexicanum plasma concentrations of thyroxine (t4) and testosterone were increased following intravenous injection of 10 micrograms luteinizing hormone-releasing hormone. a dose of 50 micrograms influenced only plasma t4 levels. this observation suggests for the first time that a hypothalamic hormone is capable of stimulating the thyroidal axis in the neotenic axolotl. | 1988 | 3056776 |
| differential cytolocalization of prosomes in axolotl during oogenesis and meiotic maturation. | the prosomes, a novel type of small rna-protein complex previously characterized in avian and mammalian cells, were isolated from axolotl (ambystoma mexicanum) oocytes and identified by sedimentation analysis and protein composition. the prosomal nature of these particles was further ascertained by immunoblot analysis with anti-duck prosome monoclonal antibodies. by in vitro [35s]methionine labelling, de novo synthesis of prosomal proteins could be detected neither during oogenesis nor meiotic m ... | 1988 | 3075616 |
| sequence, organization and transcriptional analysis of a gene encoding a u1 snrna from the axolotl, ambystoma mexicanum. | amu1, a dna fragment containing a u1 small nuclear rna (snrna)-encoding gene, was isolated from the axolotl, ambystoma mexicanum. although this u1 snrna, produced in axolotl oocytes, exhibits the lowest degree of sequence conservation among vertebrates, its secondary structure is maintained by a number of compensatory base changes. the proximal sequence element (pse) is only weakly similar to that of the previously characterized xenopus laevis pse. exchanging either the entire upstream regions w ... | 1991 | 2022330 |
| paraboloid of axolotl retinal photoreceptor and bovine pituitary thyrotropin fraction share an antigen. | lenses of newts (genera notophthalmus, triturus, cynops) regenerate from irises in the presence of retinae of larval frogs (rana) or adult salamanders (hynobius, ambystoma), species which are themselves incapable of lens regeneration from the iris. in newts, bovine pituitary thyrotropin preparation nih-tsh-b8 can also stimulate lens regeneration from the iris. an antiserum against nih-tsh-b7 (purified as is nih-tsh-b8), absorbed with bovine lutropin preparation nih-lh-b9, cross-reacts with bovin ... | 1988 | 3121378 |
| dna ligase i from xenopus laevis eggs. | we have purified the major dna ligase from xenopus laevis eggs and raised antibodies against it. estimates from sds page indicate that this dna ligase is a 180 kda protein. this enzyme is similar to the mammalian type i dna ligase which is presumed to be involved in dna replication. we have also analysed dna ligase activity during x. laevis early development. unfertilized eggs contain the highest level of activity reflecting the requirement for a large amount of dna replicative enzymes for the p ... | 1991 | 2017356 |
| reinvestigation of dna ligase i in axolotl and pleurodeles development. | we have recently shown that the exclusion process causing the replacement of dna ligases ii by dna ligase i in amphibian eggs after fertilization does not occur in the case of xenopus laevis [hardy, s., aoufouchi, s., thiebaud, p., and prigent, c., (1991) nucleic acids res. 19, 701-705]. since this result is in contradiction with the situation reported in axolotl and pleurodeles we decided to reinvestigate such results in both species. three different approaches have been used: (1) the substrate ... | 1991 | 1886765 |
| the differential transcriptional activity of two amphibian u1 small-nuclear rna genes correlates with structural differences in the proximal sequence element. | we previously analyzed the transcription of an axolotl u1 small-nuclear rna (snrna) gene (amu1) by microinjection into xenopus laevis oocytes. in such an assay, amu1 showed a low template activity compared to that of an x. laevis u1 snrna gene (xlu1b2). swapping the proximal sequence element (pse) with that of xlu1b2 was required for amu1 to acquire a transcription level equal to that of xlu1b2. in the present work, we examine the functional importance of the nucleotides that are common or diffe ... | 1992 | 1735429 |
| a synapse-specific carbohydrate at the neuromuscular junction: association with both acetylcholinesterase and a glycolipid. | with the aim of investigating the roles of carbohydrates in synapse formation, we have characterized a synapse-specific saccharide at the vertebrate neuromuscular junction. two lectins of similar specificity (dolichos biflorus agglutinin, dba, and vicia villosa-b4 agglutinin, vva-b4) stain synaptic but not extrasynaptic regions of the rat muscle fiber surface and thus define a synapse-specific carbohydrate. using these and other probes, we show that the carbohydrate moiety concentrated at the ne ... | 1988 | 3346730 |
| effects of fetal bovine serum and serum-free conditions on white and dark axolotl neural crest explants. | neural crest cells from both white mutant and dark (wildtype) axolotls (ambystoma mexicanum) were cultured in increasing concentrations of fetal bovine serum (fbs; 2 to 20%). for each explant, the total number of cells that migrated and the percent of differentiated melanophores were recorded. at concentrations of fbs above 2% melanophore differentiation was essentially equivalent (32 to 59%) for both the white and dark neural crest cultures, but subtle differences in cell behavior and different ... | 1991 | 2071543 |
| high levels of hmg1-2 protein expression in the cytoplasm and nucleus of hydrocortisone sensitive amphibian thymocytes. | a major 26 kda protein was identified in the cytoplasmic and nuclear compartments of axolotl thymocytes. a polyclonal antiserum was produced against the denatured form of this protein. high levels of 26 kda were expressed by hydrocortisone-sensitive lymphocytes which represent a major thymocyte subpopulation in young animals. however, no further expression of the 26 kda protein was observed in involuted thymus of adult animals nor in thymus of young artificially metamorphosed axolotls. the 26 kd ... | 1990 | 2097001 |
| the mhc molecules of nonmammalian vertebrates. | there is very little known about the long-term evolution of the mhc and mhc-like molecules. this is because both the theory (the evolutionary questions and models) and the practice (the animals systems, functional assays and reagents to identify and characterize these molecules) have been difficult to develop. there is no molecular evidence yet to decide whether vertebrate immune systems (and particularly the mhc molecules) are evolutionarily related to invertebrate allorecognition systems, and ... | 1990 | 2180813 |
| comparative studies on the vascular organization of carotid labyrinths of anurans and caudates. | the three-dimensional structures of the carotid labyrinth in five species of anurans representing four families (rana nigromaculata, rana catesbeiana, bufo japonicus, hyla arborea, and xenopus laevis), and three species of caudates representing three families (cynops pyrrhogaster, hynobius nebulosus, ambystoma mexicanum) were compared using vascular corrosion castings and scanning electron microscopy (sem). anuran carotid labyrinths are spherical in shape and are classified into two groups accor ... | 1990 | 2338718 |
| isolation and characterization of the third complement component of axolotl (ambystoma mexicanum). | 1. using a monoclonal anti-human c3 antibody and a polyclonal anti-cobra venom factor antibody as probes, a protein homologous to the mammalian third complement component (c3) was purified from axolotl plasma and found to be axolotl c3. 2. axolotl c3 consists of two polypeptide chains (mr = 110,000 and 73,000) linked by disulfide bonds. an internal thiolester bond in the alpha chain was identified by the incorporation of [14c]methylamine and nh2-terminal sequence from the c3d fragment of c3. 3. ... | 1990 | 2344737 |
| [effect of prolactin on sodium retention in intact and hypophysectomized ambystoma mexicanus (axolotl)]. | | 1972 | 4114885 |
| immunologic responses in the axolotl, siredon mexicanum. | | 1967 | 4166021 |
| [localisation by immunofluorescence of secretions related to thyreotropins, gonadotropins and corticotropins in axolotl pituitary(ambystoma mexicanum, shaw (author's transl)]. | | 1973 | 4358329 |
| heart development in the mexican salamander, ambystoma mexicanum. i. gross anatomy, histology and histochemistry. | | 1973 | 4684349 |
| [determination of the regeneration capacity of axolotl extremities suppressed by x-irradiation, by the method of tissue heterotransplantation]. | | 1968 | 4901842 |
| [spontaneous mutations occurring in amphibians ambystoma mexicanum shaw, pleurodeles waltlii michah, and xenopus laevis daudin]. | | 1968 | 4905265 |
| lymphosarcoma in the mexican axolotl, ambystoma mexicanum. | | 1970 | 4950974 |
| [study of the serum in the urodeles proteus anguinus laur. and ambystoma mexicanum cope. fraction by electrophoresis and widening]. | | 1965 | 4954695 |
| characteristics of the ureotelic arginase and its role in the advent of ureotelism during the metamorphosis of the mexican axolotl. | | 1967 | 5583769 |
| development and application of homologous radioimmunoassay for newt prolactin. | a specific and sensitive homologous radioimmunoassay (ria) for newt (cynops pyrrhogaster) prolactin (prl) was developed. prl isolated from newt pituitary glands was used for generating antiserum in a rabbit, for radioiodination, and for the standard. several dilutions of plasma and pituitary homogenate of newts yielded dose-response curves which were parallel to the standard curve. plasma from hypophysectomized newts showed the least amount of cross-reaction. pituitary homogenates of other speci ... | 1990 | 2354781 |
| [effect of embryonic brain extract on the forebrain of ambystoma mexicanum following unilateral resection of the right forebrain pole]. | | 1965 | 5832370 |
| characterization of axolotl heavy and light immunoglobulin chains by monoclonal antibodies. | axolotl specific antibodies to 2,4-dinitrophenyl (dnp) were purified by affinity chromatography from the sera of animals immunized with 2,4,6-trinitrophenylated sheep red blood cells (tnp-srbc). the purified anti-tnp/dnp antibodies, when analyzed by sds-page, were constituted of high molecular weight molecules, which in reducing conditions, were separated into heavy 72-88 kd and light 27-30 kd polypeptides. the axolotl heavy antibody chains strongly bound concanavalin-a and migrate faster in sds ... | 1987 | 2449389 |
| thyroid hormone receptors and iodothyronine deiodinases in the developing mexican axolotl, ambystoma mexicanum. | the mexican axolotl, ambystoma mexicanum, is a neotenous salamander that rarely undergoes anatomical metamorphosis, but can be induced to do so by administration of thyroxine (t4). the neoteny appears to be due primarily to low levels of plasma t4 secondary to a low rate of secretion of thyroid-stimulating hormone. however, other factors may also be involved. in anuran amphibia, metamorphosis is accompanied by alterations in thyroid hormone receptor concentration and marked changes in the activi ... | 1992 | 1563619 |
| induction of mesodermal tissues by acidic and basic heparin binding growth factors. | the inducing activity of two heparin binding growth factors hbgf-1 (prostate epithelial cell growth factor; acidic pi) and hbgf-2 (fibroblast growth factor; basic pi) from bovine brain has been tested on totipotent ectoderm from early amphibian (xenopus laevis, ambystoma mexicanum) embryos. both factors induced, at high concentrations, mostly compact spheres surrounded by a non-epidermal epithelium. when the concentration or time of incubation was reduced, large muscle inductions frequently orga ... | 1988 | 2451566 |
| distribution of desmosomal components in the tissues of vertebrates, studied by fluorescent antibody staining. | in previous work we used immunofluorescent staining with specific antibodies to study the distribution of five desmosomal antigens in the epithelia of different vertebrate animals. we showed that all five antigens were present in all epithelia studied in human, bovine, rat, guinea pig, chick and frog (rana pipiens) tissues. it was concluded that desmosomes are highly conserved structures. this paper extends those studies: by including three other species, a lizard (lacerta viridis), the axolotl ... | 1984 | 6378940 |
| effects of trh, bovine tsh, and pituitary extracts on thyroidal t4 release in ambystoma mexicanum. | circulating levels of t4 are measured by radioimmunoassay after intravenous injection of trh, bovine (b) tsh, and pituitary extracts in the mexican axolotl (ambystoma mexicanum). very low control levels of t4 are found (53 +/- 3 pg/ml (n = 27), but they are increased sevenfold following injection of 1/2 pars distalis extract or 1/2-1/10 iu b-tsh. increased levels following these injections are found in plasma up to 48 hr after the injection. an in vitro assay also indicates that a 1/2 pars dista ... | 1983 | 6413295 |
| difference of the in vivo responsiveness to thyrotropin stimulation between the neotenic and metamorphosed axolotl, ambystoma mexicanum: failure of prolactin to block the thyrotropin-induced thyroxine release. | basal and tsh-induced plasma concentrations of t4 have been measured by radioimmunoassay in the neotenic and metamorphosed male axolotl ambystoma mexicanum both before and after an ovine prolactin pretreatment. all injections are made into the vena abdominalis. basal levels of t4 are low in neotenes (85 +/- 19 pg/ml) and somewhat higher in metamorphosed ambystoma (171 +/- 39 pg/ml), but are increased during metamorphosis (1094 +/- 138 pg/ml). following injection of 5 mu bovine tsh circulating le ... | 1984 | 6510692 |
| diverse supernumerary structures develop after inverting the anteroposterior limb axis of the anuran. | contralateral limb bud graftings were performed on tadpoles of the anuran bufo bufo. the anteroposterior axis was inverted while the larvae were at stage iv or v (e.g., between 22-30 days after fertilization). eighty-four tadpoles were operated on, 10 of which were used as controls. at anterior or posterior location 104 supernumerary structures developed in toto. they were collected and whole-mount examined after being stained with alcian blue. they were further prepared for serial sectioning, m ... | 1989 | 2466718 |
| biosynthesis of sulfated proteoglycans in amphibian embryonal cells. | the synthesis of sulfated proteoglycans in small explants from various parts of late blastulae from ambystoma mexicanum or xenopus laevis was investigated by incorporation of radioactive sulfate or glucosamine and galactosamine in media of low, normal or high tonicity. the explants differentiated into ciliated aggregates of fibroblast-like cells, or remained undifferentiated depending upon their origin in the embryo. high tonicity induces the explants to dissociate and prevents morphological dif ... | 1989 | 2504303 |
| regulatory peptides (glucagon, somatostatin, substance p, and vip) in the brain and gastrointestinal tract of ambystoma mexicanum. | the concentrations of immunoreactive components of glucagon, somatostatin, substance p, and vasoactive intestinal polypeptide (vip) in the brain, stomach, and gut of the neotenic mexican axolotl (ambystoma mexicanum) were determined by radioimmunoassay using antibodies of defined regional specificity. the molecular forms of the immunoreactive components were analyzed by high-performance liquid chromatography (hplc). the concentrations and molecular forms of somatostatin and vip in axolotl brain ... | 1985 | 2580753 |
| [nuclear behavior of the growing oocytes of the clawed frog in the cytoplasm of the maturing oocytes of the axolotl]. | | 1983 | 6641489 |
| the distribution of small ions during the early development of xenopus laevis and ambystoma mexicanum embryos. | the free ion concentrations of na+, k+ and cl- have been measured in the cells and intercellular spaces of developing amphibian embryos using ion-sensitive microelectrodes. ca2+, h+ and buffering capacity have also been measured in the intercellular spaces. the free intracellular na+ and k+ concentrations in the early cleavage stages remain approximately constant at 21 mm and 90 mm respectively. the free intracellular cl- concentration, approximately 60 mm during the egg to 4-cell stage, falls d ... | 1983 | 6655587 |
| evolution of motor patterns: aquatic feeding in salamanders and ray-finned fishes. | patterns of muscle activity (motor patterns) have generally been found to be strongly conserved during the evolution of aquatic feeding behavior within closely related groups of fishes and salamanders. we conducted a test of the generality of motor pattern conservation with a much broader phylogenetic scope than has been done previously. activity patterns of three cranial muscles were quantified from electromyographic (emg) recordings made during suction feeding in a salamander (ambystoma mexica ... | 1989 | 2611639 |
| spatial aspects of neural induction in xenopus laevis. | a monoclonal antibody, 2g9, has been identified and characterised as a marker of neural differentiation in xenopus. the epitope is present throughout the adult central nervous system and in peripheral nerves. staining is first detected in embryos at stage 21 in the thoracic region. by stage 29 it stains the whole central nervous system, except the tail tip. the epitope is present in a 65k mr protein, and includes sialic acid. the antibody also reacts with neural tissue in mice and axolotls and n ... | 1989 | 2632233 |
| amphibian (urodele) myotomes display transitory anterior/posterior and medial/lateral differentiation patterns. | myotome differentiation during mexican axolotl (ambystoma mexicanum) somitogenesis was analyzed by employing anti-actin and anti-myosin monoclonal antibodies as molecular probes. myotome differentiation occurs after segmentation and proceeds in the cranial-to-caudal direction along the somite file. within individual somites myotome differentiation displays distinct polarities. examination of the somite file at the tailbud stage revealed that soon after segmentation, actin/myosin accumulate predo ... | 1989 | 2647546 |
| immunocytochemical localization and immunochemical characterization of an insulin-related peptide in the pancreas of the urodele amphibian, ambystoma mexicanum. | the pancreas of the axolotl, ambystoma mexicanum, was investigated by immunocytochemical methods for the presence of immunoreactivity to a number of antisera raised against mammalian insulins. all anti-insulin antisera tested revealed substantial amounts of reaction products confined solely to the aldehyde-fuchsinophilic b cells of the endocrine pancreas. the reactive cell population was detected by use of one polyclonal antiserum against bovine insulin and eight different monoclonal antibodies ... | 1989 | 2663173 |
| survey of the numbers and species of amphibia used in the united kingdom in 1977. | this survey suggests that about 115 000 amphibia, of which more than half were rana temporaria, were supplied for use in teaching and research in the uk during 1977. as only 27 000 were recorded as being used by universities, polytechnics and research institutes, probably mostly for teaching, it must be assumed that the majority are used for teaching purposes in schools. there has been an increase in the proportion of amphibia supplied by recognised suppliers, and also in that being 'purpose-bre ... | 1980 | 6965743 |
| thymus dependency in anti-trinitrophenyl (tnp) binding responses in the spleen of ambystoma mexicanum. effects of thymectomy and anti-thymocyte serum treatments. | | 1981 | 6970685 |
| analysis of actin and tropomyosin in hearts of cardiac mutant axolotls by two-dimensional gel electrophoresis, western blots, and immunofluorescent microscopy. | when homozygous, recessive mutant gene c in ambystoma mexicanum results in a failure of embryonic heart function. this failure is apparently due to abnormal inductive influences from the anterior endoderm resulting in an absence of normal sarcomeric myofibril formation. biochemical and immunofluorescent studies were undertaken to evaluate the contractile proteins actin and tropomyosin in normal and mutant hearts. for the immunofluorescent studies, cardiac tissues were fixed in periodate-lysine-p ... | 1989 | 2664186 |
| [histochemical study of the cholinesterases of various formations of the vertebrate endbrain]. | histochemical studies have been made on true (ache) and false (bche) cholinesterases in different parts of the telencephalon of amphibians, reptiles and mammals. the data obtained indicate that the enzymic localization depends on both the level of the development of the brain and phylogenetic age of its individual formations. in the telencephalon of ambystoma mexicanum, high concentration of ache was found in vascular-capillary network, in other investigated amphibians (triturus vulgaris, rana t ... | 1981 | 6976662 |
| regulation of antibody synthesis in the x-irradiated mexican axolotl. | the effects of x-irradiation were studied on the mexican axolotl antibody synthesis. to reduce the anti-horse red blood cell (hrbc) antibody titers, 150 rd and smaller doses are ineffective, 200-450 rd are increasingly effective, and 700 rd are maximally effective (and lethal). a significant enhancement of the anti-hrbc titers was observed in low doses (50-150 rd x-irradiated animals). this enhancement was also observed when a low x-ray dose was applied only on the thymic areas. in whole body, b ... | 1981 | 7028489 |
| immunocytochemical localization and spatial relation to the adenohypophysis of a somatostatin-like and a corticotropin-releasing factor-like peptide in the brain of four amphibian species. | the distribution of somatostatin (srif) - and corticotropin-releasing factor (crf)-like - immunoreactive material was studied in the brain of four amphibian species (ambystoma mexicanum, pleurodeles waltlii, xenopus laevis, rana ridibunda) by use of immunocytochemistry. a wide network of srif-immunoreactive fibers and numerous perikarya were observed in all amphibians examined, with a dense accumulation of nerve endings in the external layer of the median eminence (elme). in the representatives ... | 1987 | 2880668 |
| antibody diversity in amphibians. noninbred axolotls used the same unique heavy chain and a limited number of light chains for their anti-2,4-dinitrophenyl antibody responses. | noninbred axolotls (ambystoma mexicanum, amphibia, urodela) were immunized with trinitrophenylated sheep red blood cells (tnp-srbc) and anti-2,4-dinitrophenyl (dnp)/tnp antibodies were individually purified by affinity chromatography. the isolated igm-like antibodies were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (sds-page) and isoelectric focusing (ief) under reducing conditions. the sds-page and ief-separated heavy (h) and light (l) chains were electroblotted onto n ... | 1987 | 3106061 |
| peaks of neuronal membrane antigen and thyroxine in larval development of the mexican axolotl. | | 1982 | 7160616 |
| a variant cardiac tropomyosin in the salamander, ambystoma mexicanum. | | 1982 | 7182078 |
| thyroxine and triiodothyronine in plasma and thyroids of the neotenic and metamorphosed axolotl ambystoma mexicanum: influence of trh injections. | circulating levels of t3 and t4, as well as t3 and t4 content of the thyroid glands were measured by radioimmunoassay in the neotenic and metamorphosed axolotl ambystoma mexicanum. in the two experiments which were performed plasma t4 concentrations were more elevated in metamorphosed axolotls, especially in the first experiment (2.12 +/- 0.40 ng/ml vs. 369 +/- 30 pg/ml). t3 plasma values which were only estimated in the second experiment were about five times higher in metamorphosed animals (63 ... | 1988 | 3131185 |
| injection of an antibody against a p21 c-ha-ras protein inhibits cleavage in axolotl eggs. | the presence of a ras protein was demonstrated in cleaving axolotl eggs by selective immunoprecipitation with a polyclonal antibody against a peptide encoded by the c-ha-ras oncogene, cellular homolog of the v-ha-ras oncogene of harvey rat sarcoma virus. injection of this antibody into axolotl oocytes subjected to progesterone treatment does not prevent meiotic maturation. injection of the same antibody into a blastomere of axolotl eggs at the 2- or 4-cell stage causes cleavage arrest in the des ... | 1988 | 3277177 |
| dominant lethal induction by ethyl methanesulfonate in the male axolotl (ambystoma mexicanum). | when male axolotls (ambystoma mexicanum) were treated with ethyl methanesulfonate (ems) and mated at regular intervals thereafter, the incidence of embryonic abnormalities among the f1 progeny increased until a time was reached when none survived to hatching. at 100 mg/1 ems, this point was reached about 130 days after treatment. thereafter, the frequency of abnormalities gradually decreased to control levels. at higher concentrations, abnormalities were seen in spawnings obtained sooner after t ... | 1980 | 7462966 |
| basal lamina is not a barrier to neural crest cell emigration: documentation by tem and by immunofluorescent and immunogold labelling. | one of the factors proposed to control initiation of migration of neural crest (nc) cells is disruption of the basal lamina (bl) that is presumed to exist over the dorsal portion of the neural tube. previously, we discovered that, in the mouse embryo, a continuous bl is not deposited over the dorsal portion of the neural tube until emigration of the nc cells is terminated. here, we show that the pattern of bl deposition in chick embryos is similar, but not identical, to that in the mouse. in par ... | 1987 | 3332260 |
| factors involved in the formation and stabilization of cell aggregates obtained from amphibian embryonic explants. | the effect of factors influencing the formation and stability of animal and vegetal aggregates from xenopus laevis and ambystoma mexicanum was examined in the light and scanning electron microscopes. at extreme values of ph the surface coat covering the vegetal aggregates is dissolved and dissociation may take place. animal aggregates are more resistant. at high tonicities vegetal aggregates may be dissociated, and in the animal aggregates the epidermal differentiation is suppressed. in the abse ... | 1988 | 3370680 |
| identification and expression of a homologue of the murine hoxa5 gene in the mexican axolotl (ambystoma mexicanum). | an excellent model for studying heart development in vertebrates is the cardiac non-function lethal mutant (gene c) mexican axolotl, ambystoma mexicanum. in order to facilitate our analyses of the mutant system, we have undertaken a search for stage-specific molecular markers during embryonic development of the axolotl. we have concentrated on homeobox genes as suitable candidates for monitoring molecular changes during development. a 270-bp probe encoding a portion of the axolotl homeobox gene ... | 1995 | 7557438 |
| behavioral development in the absence of neural activity: effects of chronic immobilization on amphibian embryos. | embryos of xenopus laevis and ambystoma mexicanum were continually immobilized from premotile stages of development to stages at which normally reared embryos were swimming well. immobilization was achieved through exposure to solutions of chloretone, lidocaine, or alpha-bungarotoxin. at a number of stages after recovery from the drugs, spontaneous and stimulated behaviors were extensively quantified. immobilization of ambystoma embryos resulted in temporary defects in musculoskeletal developmen ... | 1986 | 3711983 |
| myelin lipids: a phylogenetic study. | the lipid composition of cns and pns myelin was studied in rat, xenopus, trout and torpedo. the main difference lay in the proportion of cerebrosides, which decreased in the sequence rat greater than xenopus greater than torpedo greater than trout. in addition torpedo cns and pns myelins were extremely rich in sulfatides. in some respects, torpedo appeared closer to tetrapods than trout. otherwise the proportion of the different lipid classes did not reveal any clear evolutionary trends. the pre ... | 1986 | 3785545 |
| axolotl retina and lens development: mutual tissue stimulation and autonomous failure in the eyeless mutant retina. | during eye development in the axolotl (ambystoma mexicanum shaw), morphogenetic movements bring together tissues from head epidermis, neuroectoderm and neural crest. the stages 0 to 14 of axolotl eye development were expanded from rabl's (1898) stages 1 to 10 and correlated with harrison's (1969) stages. at the onset of neurulation (stage 13 of harrison), the head epidermis is already determined to form skin, and the neuroectoderm is committed to form brain, because these tissues develop autonom ... | 1986 | 3805980 |
| cloning, sequencing and expression of an isoform of cardiac c-protein from the mexican axolotl (ambystoma mexicanum). | c-protein, a myosin binding protein, is thought to regulate and stabilize thick filaments during assembly of sarcomeric a-bands. multiple isoforms of c-protein have been characterized in avian and mammalian systems. we now report the isolation and the nucleic acid sequence of a partial c-protein cdna clone from an axolotl heart cdna expression library in lambda gt11. the clone was isolated by screening the library with a heterologous monoclonal anti-c-protein antibody (mf1). sequence comparison ... | 1995 | 7639739 |
| developmental mutants isolated from wild-caught xenopus laevis by gynogenesis and inbreeding. | xenopus laevis obtained from indigenous african populations are a rich source of mutants affecting development. gynogenesis and inbreeding were used to isolate mutants affecting development from wild-caught xenopus laevis females. fourteen mutants were recovered from eight females tested. one mutant was recovered from each of two females. this load of 1.875 developmental mutants per female is similar to that found in the axolotl (ambystoma mexicanum), a urodele amphibian, and is only slightly le ... | 1985 | 3973558 |
| studies on the advent of ureotelism. factors that render the hepatic arginase of the mexican axolotl able to hydrolyse endogenous arginine. | 1. a study was undertaken of the conditions that might operate in the synthesis and hydrolysis of arginine by axolotl liver homogenate to test a previous postulate that liver arginase of the non-metamorphosed mexican axolotl is not able to hydrolyse arginine formed from citrulline and aspartic acid, though it can split exogenous arginine, and also that an enhanced capacity to hydrolyse endogenous arginine plays a major role in the advent of ureotelism observed during the metamorphosis of the axo ... | 1968 | 5701670 |
| expression of pax-6 during urodele eye development and lens regeneration. | regeneration of eye tissues, such as lens, seen in some urodeles involves dedifferentiation of the dorsal pigmented epithelium and subsequent differentiation to lens cells. such spatial regulation implies possible action of genes known to be specific for particular cell lineages and/or axis. hox genes have been the best examples of genes for such actions. we have, therefore, investigated the possibility that such genes are expressed during lens regeneration in the newt. the pax-6 gene (a gene th ... | 1995 | 7761453 |
| the identification and partial cloning by pcr of the gene for tyrosinase-related protein-1 in the mexican axolotl. | the tyrosinase gene family is currently composed of three members, tyrosinase and two tyrosinase-related proteins, trp-1 and trp-2. these three gene products have all been found to act in the synthesis of melanin pigments with the enzyme tyrosinase catalyzing the initial rate-limiting steps. thus far these genes have primarily been analyzed in higher vertebrates. we have used degenerate pcr primers to isolate a large fragment of an axolotl tyrosinase-related protein. sequence analysis of the ent ... | 1995 | 7792254 |
| the evolution of efferent vagal control of the heart in vertebrates. | in vertebrates vagal preganglionic neurons are found in two principle locations in the brain-stem, the dorsal vagal motor nucleus and areas lateral to the dorsal vagal motor nucleus centered on the nucleus ambiguus. in elasmobranch fish 8% of vagal preganglionic neurons are located outside the dorsal vagal motor nucleus; these are all cardiac vagal motoneurones. this proportion increases from fish through amphibians to mammals in which over 30% of vagal preganglionic neurons are outside the dors ... | 1994 | 7827254 |