Publications

[induction of haploid androgenesis in the axolotl by ultraviolet irradiation and a cytomorphological study of the mechanism of its origin].		2003	5896234
a recessive factor (o, for ova deficient) determining a complex of abnormalities in the mexican axolotl (ambystoma mexicanum).		1966	5923194
the influence of beta-aminopropionitrile on the cartilage matrix of the regenerating limbs of the axolotl (ambystoma mexicanum). a histochemical study.		1966	5957964
[the effect of colchicine on the spinal cord regeneration of ambystoma mexicanum after extirpation of a small section].		1966	5982866
[the influence of the feeding of embryonal liver tissue on the tail regeneration of ambystoma mexicanum, with special consideration of the regeneration of the tail spinal cord].		1966	5988091
[the role of trauma in the restoration of regeneration capacity in axolotl extremities, inhibited by x-irradiation].		1966	5997300
[changes in sulfhydryl group content in extremities tissues of axolotl under inhibition of their regeneration capability by x-irradiation and its restoration].		1966	5998247
[intracellular recording of responses from different frog and axolotl retinal cells].		1966	6003846
[experimental production of diploid androgenesis in the axolotl by the method of the combined action of ultraviolet rays and heat shock].		1966	6010499
the response of the gil epithelium of the adult axolotl (siredon mexicanum) to roentgen radiation.		1967	6020196
expression of specific pteridines in neural crest transplants between pleurodeles and axolotl.		1967	6034431
[light and electron microscope observations on the taste buds of the axolotl tongue].		1967	6051698
albino axolotls from an albino tiger salamander through hybridization.		2003	6055330
spheroidal and ring nucleoli in amphibian oocytes. patterns of uridine incorporation and fine structural features.	in maturing oocytes of the newt triturus viridescens, the nucleoli undergo a series of morphological changes that are very similar to those described by callan for the axolotl, ambystoma mexicanum. the nucleoli first assume the form of spheroids which then become extended into ring or necklace shapes that are dnase-sensitive; in mature oocytes the nucleoli revert to a spheroidal form. short term in vitro incorporation studies with uridine-(3)h on both species show that rna synthesis occurs in a ...	1967	6055993
an analysis of distal dominance in the regenerating limb of the axolotl.		1967	6062893
actinomycin d: effect on induced metamorphosis in the mexican axolotl.		1967	6076906
a voltage-gated hydrogen ion current in the oocyte membrane of the axolotl, ambystoma.	membrane currents in the immature oocyte of the urodele amphibian ambystoma were studied using the two-micro-electrode voltage-clamp technique. a current carried by h ions (ih) constituted the major portion of outward current activated by depolarizations from the resting voltage (about -60 mv). net inward current was not observed at this developmental stage. the reversal potential for ih measured from tail currents obtained in two step voltage-clamp experiments shifted by 54 mv per unit change i ...	1984	6086909
off-pathway synaptic transmission in the outer retina of the axolotl is mediated by a kainic acid-preferring receptor.	intracellular recordings were made from off-centre bipolar cells and horizontal cells in the superfused axolotl retina eyecup preparation. bath-applied (+/-)cis-2,3-piperidine dicarboxylic acid (pda), gamma-d-glutamylglycine (dgg), l-glutamic acid diethyl ester (gdee), (+/-)2-amino-5-phosphonovaleric acid (2-apv) and magnesium ions were assessed as antagonists of the actions of the photoreceptor transmitter. the rank order of antagonist efficacy was pda greater than dgg greater than greater than ...	1984	6093015
enzyme clusters during the metamorphic period of ambystoma mexicanum: role of thyroid hormone.	enzyme activities and dna content have been measure in axolotl liver during the metamorphic period (4-8 months after spawning). three different types of enzyme activity profiles were observed. in the type i profile (carbamoyl-phosphate synthase, arginase, ornithine transcarbamoylase, and glutamate dehydrogenase) enzyme activity is high in the youngest animals studied, and shows a minimum at 5 months followed by a maximum at 8 months of age. thereafter activities do not change or slightly decreas ...	1982	6128371
the effects of adenyl compounds on the heart of the axolotl (ambystoma mexicanum).	in the spontaneously beating axolotl atrium, adenosine 5'-triphosphate (atp) produced initial excitation followed by inhibition and then by a secondary excitation. this third phase of the atp response was only seen in electrically driven preparations in the presence of 8-phenyltheophylline (8-pt), an adenosine receptor antagonist. alpha,beta-methylene atp (apcpp), a stable analogue of atp, produced only excitatory effects, while adenosine and beta,gamma-methylene atp (appcp), a slowly degradable ...	1983	6140115
is the na+,k+-atpase symmetrically distributed in the neuroepithelium of the vestibular system in the axolotl (ambyostoma mexicanum)?	this study was undertaken to assess the localization of the na+,k+-atpase in the neuroepithelial cells of the macula sacculi. in vitro perilymphatic (basolateral) perfusion with ouabain produced a significant drop in the membrane potential. endolymphatic (apical) application of ouabain had practically no effect on membrane potentials. this suggests that na+,k+-atpase is asymmetrically distributed in the neuroepithelial cells.	1984	6151945
the alveolar-lining layer in the lung of the axolotl, ambystoma mexicanum. an electron-microscopic study using heavy metal complexes.	lungs of neotenic larvae of ambystoma mexicanum were prepared for maintaining the air-tissue boundary during aldehyde fixation. four methods of postfixation were applied: 1) osmium tetroxide followed by en-bloc staining with uranyl acetate and phosphotungstic acid, 2) ruthenium redosmium tetroxide, 3) osmium tetroxide-ferrocyanide, and 4) tannic acid-osmium tetroxide. three types of cells line the inner surface of the axolotl lung: 1) pneumocytes, covering the capillaries with flat cellular exte ...	1982	6174238
has prolactin an intermedin-like activity on the integument of the axolotl?	skin explants of the neotenic form of ambystoma tigrinum (axolotl) have been kept in culture during several days. when alpha-msh or prolactin are added to the medium, a dispersion of melanin in melanosomes is observed. the reaction is reversible in the case of prolactin when the explants are transferred in the medium without hormones. furthermore with prolactin, expansion of melanin in dermal melanophores is a more permanent and highly reproducible phenomenon, compared with the action of alpha-m ...	1981	6176199
expansion of the visual projection to the tectum of axolotls during metamorphosis.	during artificially induced metamorphosis in axolotls, the indirect visual projection from the ipsilateral eye develops followed by the expansion of the contralateral direct projection to occupy most of the tectal surface. during expansion the ipsilateral input is temporarily lost indicating the functional interdependence of the two projections. final stabilization of the projections and congruence of the ipsilateral and contralateral inputs is achieved a month after arrival on land.	1982	6185185
the genes coding for 4 snrnas of drosophila melanogaster: localization and determination of gene numbers.	four small nuclear rnas (snrnas) have been isolated from drosophila melanogaster flies. they have been characterized by base analysis, fingerprinting, and injection into axolotl oocytes. the size of the molecules and the modified base composition suggest that the following correlations can be made: snrna1 approximately u2-snrna; snrna2 approximately u3-snrna; snrna3 approximately u4-snrna; snrna4 approximately u6-snrna. the snrnas injected into axolotl oocytes move into the nuclei, where they ar ...	1983	6191277
improved techniques for use of the triploid cell marker in the axolotl, ambystoma mexicanum.	techniques for using the triploid cell marker for studying cell lineage during the development and regeneration of the axolotl limb are described. triploid animals possess cells with three nucleoli while diploid animals possess cells with two nucleoli. we have developed a technique for isolating the limb dermis as a sheet of cells for whole-mount analysis of cellular ploidy. whole-mount tissue preparations as well as paraffin-embedded sectioned tissues were stained specifically for nucleoli with ...	1984	6205921
[effects of exogenous tsh on the thyroid activity of adult or neotenic amphibians].	in adult anuran and neotenic urodela, bred in laboratory conditions, the levels of plasma thyroid hormones are undetectable (t3 less than 50 ng/100 ml, t4 less than 5 ng/100 ml). thyroid function can be reactivated after ovine tsh treatment. under those conditions, metamorphosis is induced in the axolotl and t4 plasmatic levels reaches 0,53 +/- 0,13 micrograms/100 ml and those of t3 9 +/- 2,64 ng/100 ml. in adult anuran, thyroid reactivation under thyrotropic treatment determines an increased se ...	1982	6220788
equilibrium properties of a voltage-dependent junctional conductance.	the conductance of junctions between amphibian blastomeres is strongly voltage dependent. isolated pairs of blastomeres from embryos of ambystoma mexicanum, xenopus laevis, and rana pipiens were voltage clamped, and junctional current was measured during transjunctional voltage steps. the steady-state junctional conductance decreases as a steep function of transjunctional voltage of either polarity. a voltage-insensitive conductance less than 5% of the maximum remains at large transjunctional vo ...	1981	6259274
suppression of sprouted synapses in axolotl muscle by transplanted foreign nerves.	1. the supracoracoideus (s.c.) muscle of the axolotl shoulder is innervated by two nerves, the anterior and posterior s.c. nerves. the posterior nerve was induced to make synapses outside its normal territory in the muscle by removing a segment of the anterior nerve. intracellular recording indicated that the efficacy of transmission from posterior nerve terminals outside their normal territory increased over several weeks prior to the return of the anterior nerve. 2. the anterior nerve reinnerv ...	1980	6259337
hormonal control of glycogenolysis and the mechanism of action of adrenaline in amphibian liver in vitro.	in in vitro cultures of liver from ambystoma mexicanum glycogenolysis was stimulated by adrenaline, glucagon, and vasopressin in a dose-dependent manner. maximum activity was seen at 10(-6) m hormone while 10(-9) m was without effect. dibutyryl cyclic amp (10(-3) m) stimulated glycogenolysis maximally although 10(-5) m had no effect. the glucose release brought about by adrenaline was blocked by the beta-adrenergic antagonist propranolol but not by prazosin or yohimbine which are alpha 1- and al ...	1983	6301936
ribosomal 5s genes in relation to c-value in amphibians.	we have measured the amount of 5s-ribosomal dna in the genomes of xenopus laevis, triturus cristatus carnifex and ambystoma mexicanum, three species of amphibians which have widely different c-values. our best estimate is that these organisms have about 24,000, 32,000 and 61,000 5s-genes per haploid genome respectively. a trend to increasing 5s gene copynumber with increasing c-values in amphibians is apparent, probably linked to the need to supply more ribosomes to the larger cells which are as ...	1983	6304650
axonal pathfinding in the absence of normal pathways and impulse activity.	retinal axons were challenged to grow to their targets both along abnormal pathways and in the absence of impulse activity. eye primordia were first transplanted from normal to ectopic sites in axolotl embryos. most of the hosts were genetically eyeless, others were enucleated normal embryos. these axolotl embryos were then parabiotically joined to california newt embryos. both operations were completed by stage 28, which is before axons have left the eye. the result of the parabiosis was a para ...	1984	6325605
anchoring filaments of the amphibian epidermal-dermal junction traverse the basal lamina entirely from the plasma membrane of hemidesmosomes to the dermis.	an electron microscopical study of the epidermal-dermal junction in the axolotl and adult rana pipiens has been carried out. this shows that filaments of about 12nm in diameter, known as anchoring filaments, pass from the hemidesmosomes at the base of the epidermal cells across the basal lamina to the dermis. there they may unite to form broader fibres, known as anchoring fibrils, or may simply form bundles. in the axolotl, particularly, the anchoring fibrils or bundles of anchoring filaments, e ...	1984	6335885
maturation of transplantation antigens in ambystoma mexicanum.	both juvenile (14-16 week) and adult (18 month) ambystoma mexicanum reject skin allografts from adult ambystoma more speedily than they reject such grafts from juvenile axolotls. donor-specific histocompatibility antigen, prepared from splenocytes, is more effective in inhibiting adult host splenocyte migration when the antigen is prepared from spleen cells from adult, rather than from juvenile ambystoma. the thymus is fully developed in juvenile ambystoma, suggesting that the delayed kinetics o ...	1983	6341109
positional information in the forelimb of the axolotl: properties of the posterior skin.	two series of experiments were carried out to investigate the properties of the positional information carried by posterior skin of the axolotl forelimb. the skin was assayed by grafting it to the anterior side of a normal limb and then amputating through the graft region. the formation of a double posterior regenerate indicates that the grafted skin carried the posterior coding. in the first series, double posterior limbs were created by grafting posterior half limb rudiments to the flank of ta ...	1983	6348201
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
the distribution of marked dermal cells from small localized implants in limb regenerates.	numerous experiments have demonstrated that skin has a profound influence on the pattern of limb regeneration in urodeles. in this investigation, the fate during regeneration of marked cells derived from narrow strips of skin inserted into different positions around the limb circumference has been followed. skin strips were taken from triploid axolotls and transplanted into diploid sibling animals. the distribution of trinucleolate cells was determined at the site of amputation and in the regene ...	1984	6389219
[formation of the gray crescent, induced in axolotl oocytes during maturation, depends on factors of nuclear origin].	inhibitors of protein synthesis can elicit the precocious appearance of a grey crescent (gc) in in vitro maturing ambystoma mexicanum oocytes. this treatment however fails to induce gc formation when the oocytes are enucleated before initiation of maturation. the ability to form a gc is reestablished in enucleated oocytes by the injection of nucleoplasm from a normal oocyte, either before or after injection of the inhibitor. in the latter case, the gc appears even though the protein synthesis le ...	1983	6412990
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
accumulation and localization of troponin-t in developing hearts of ambystoma mexicanum.	troponin-t (tn-t) expression in developing hearts of axolotls, ambystoma mexicanum, was studied with the use of polyclonal and monoclonal antibodies and sds-polyacrylamide gel electrophoresis. in precontractile hearts (stage 32/33), tn-t was present in addition to myosin, actin and tropomyosin as evidenced by the presence of the protein bands in sds-gels and by indirect immunofluorescence. tn-t was localized in amorphous collections at the peripheries of these precontractile cells. hearts of nor ...	1984	6442732
cellular contribution to supernumerary limbs in the axolotl, ambystoma mexicanum.	using the triploid cell marker, the cellular contribution from graft and stump to the supernumerary limbs which result from controlateral grafts of limb buds and regeneration blastemas in the axolotl has been analyzed. grafts were made so as to appose anterior and posterior limb positions. overall, the contribution from graft and stump tissue was found to be approximately equal although the position of the boundary between the two was variable from limb to limb. this result is consistent with mo ...	1984	6468757
cellular contribution to supernumerary limbs resulting from the interaction between developing and regenerating tissues in the axolotl.	the relationship between limb development and limb regeneration is considered with regard to the mechanisms by which pattern is established during limb outgrowth. in a previous paper (muneoka, k. and bryant, s. v. 1982 nature (london) 298, 369-371) the interaction between cells from the developing limb bud and the regenerating limb blastema was found to result in the production of organized supernumerary limb structures. in this paper the relative cellular contribution from developing and regene ...	1984	6468758
the pigmentary system of developing axolotls. i. a biochemical and structural analysis of chromatophores in wild-type axolotls.	a biochemical and transmission electron microscopic description of the wild-type pigment phenotype in developing mexican axolotls (ambystoma mexicanum) is presented. there are three pigment cell types found in adult axolotl skin - melanophores, xanthophores and iridophores. both pigments and pigment cells undergo specific developmental changes in axolotls. melanophores are the predominant pigment cell type throughout development; xanthophores occur secondarily and in fewer numbers than melanopho ...	1984	6470605
the pigmentary system of developing axolotls. ii. an analysis of the melanoid phenotype.	the melanoid mutant in the mexican axolotl (ambystoma mexicanum) is analysed with respect to the differentiation of pigment cells. pigment cells were observed with the transmission electron microscope in order to determine any unusual structural characteristics and to determine what happens to each of the cell types as development proceeds. chemical analysis of pteridine pigments was also carried out, and changes in pteridine biosynthesis were found to correlate well with changes in xanthophore ...	1984	6470606
regeneration of surgically created mixed-handed axolotl forelimbs: pattern formation in the dorsal-ventral axis.	the regeneration of surgically created mixed-handed limb stumps is examined in the axolotl. operations were performed in the lower arm and upper arm regions and grafts were allowed to heal for approximately one month prior to amputation or were amputated immediately. in the lower arm group both anterior and posterior limb halves were inverted, whereas only posterior halves were inverted in the upper arm group. almost all the limbs regenerated were normal in the anterior-posterior axis, whereas a ...	1984	6491582
[nuclear behavior of embryonic cells and growing oocytes from the clawed toad in the cytoplasm of maturing axolotl oocytes].	the behaviour of the nuclei of the x. laevis vitellogenic oocytes was studied by their transplantation into the cytoplasm of the axolotl maturing oocytes. after the germinal vesicle breakdown, in the case the transplanted nuclei were located close to each other a common giant spindle united the chromosomes of all transplanted nuclei. a mosaic spindle united sometimes the chromosomes of the two amphibian species. the embryonic nuclei transplanted in the cytoplasm of the maturing oocytes formed, a ...	2006	6504501
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
[radioautographic study of the cellular proliferation of retinal pigment epithelium in axolotls].	the proliferative activity of the pigment epithelium cells in the axolotl eyes was studied using 3h-thymidine in two types experiments: after the removal of lens, iris and retina and upon the cultivation of the pigment epithelium pieces in the cavity of lens-less eye. irrespective of the operation type, the level of proliferation of the pigment epithelium cells changed regularly with respect to the time of observation. in the intact eye, the level of proliferation of the pigment epithelium cells ...	2006	6521975
the cellular contributions of blastema and stump to 180 degrees supernumerary limbs in the axolotl.	by inverting triploid blastemas onto diploid stumps (and vice versa) the cellular contributions to supernumerary limbs so generated have been assessed. the four classes of 180 degrees supernumerary limbs each had a different mixture of stump and blastemal cells. the mesoderm of normal supernumeraries was composed entirely or almost entirely of stump cells and were always of stump handedness. the mesoderm of symmetrical supernumeraries was of variable composition, it could be mostly stump, mostly ...	1984	6533251
the response of denervated axolotl arms to delayed amputation.	forearms of juvenile axolotls can be kept denervated for up to 4 weeks by deflecting brachial nerves to the flank. a more orthodox second denervation prolongs this state up to a total of six weeks. the denervated arms are unable to regenerate for the whole period, but eventually become reinnervated and then regenerate normally. these results and analogous experiments on adult newts prompt a partial retraction and reinterpretation of my previous report on regeneration after prolonged denervation.	1984	6533253
common mechanisms in vertebrate axonal navigation: retinal transplants between distantly related amphibia.	embryonic eye primordia were transplanted from the anuran, xenopus laevis, to the urodele, ambystoma mexicanum, in order to assess whether retinal axons of one species could grow to appropriate central targets in a distantly related species. to trace the early retinal projections, xenopus primordia were removed, incubated for 20 min in a solution containing [3h]proline, washed, and then transplanted to host axolotl embryos. genetically eyeless hosts were used in some of the experiments so that t ...	1984	6536722
calmodulin during development and metamorphosis in urodelan amphibians.	calmodulin isolated and purified to homogeneity from young larvae is very similar to that obtained from adult pleurodeles waltlii and these proteins are almost identical to previously described vertebrate calmodulins. during p. waltlii development, an increase in total individual calmodulin content is observed after the heart beating stage. in dorsal axial muscle, calmodulin level which is very high at the beginning of larval life (premetamorphosis) decreases strikingly in the first part of prom ...	1984	6537929
control of dna ligase molecular forms in nucleocytoplasmic combinations of axolotl and pleurodeles.	a light form of dna ligase (ec 6.5.1.2), the only form present in oocytes of the axolotl (ambystoma mexicanum), has been shown to be replaced by a heavy form of the enzyme when the egg enters cleavage. this early biochemical event has been assumed to rely on direct nuclear input. sucrose gradient analysis permits discrimination between enzymes from axolotl and the sharp-ribbed salamander (pleurodeles waltlii) for both heavy and light enzymatic forms of dna ligase. genetic activity of blastula nu ...	1983	6574490
perpendicular orientation and directional migration of amphibian neural crest cells in dc electrical fields.	the behavior of cultured neural crest cells of ambystoma mexicanum and xenopus laevis in dc electrical fields was studied. in fields of 1-5 v/cm, isolated or confluent cells retract both their anode- and cathode-facing margins. subsequently, the cells elongate, with protrusive activity confined to their narrow ends. in larger fields (greater than or equal to 5 v/cm), protrusions form on the cathode-facing sides of the perpendicularly oriented cells. the cells then begin migrating laterally, perp ...	1984	6582473
[an anatomical study of teeth in the axolotl (siredon mexicanum)].		1983	6585764
fertilization of amphibian eggs: a comparison of electrical responses between anurans and urodeles.	in pleurodeles waltl and ambystoma mexicanum, which exhibit physiological polyspermy, the membrane potential in most eggs did not change in any consistent pattern during 45 min after fertilization; in some cases, a slow hyperpolarization began 5 to 15 min after insemination and continued for 10-15 min. these eggs then slowly depolarized, reaching a stable value of -10 to +10 mv, about 45 min after fertilization. membranes of eggs activated by a23187 or by electrical stimulus showed a similar beh ...	1983	6603379
the effect of vitamin a on limb regeneration in rana temporaria.	previous experiments in which vitamin a has been administered to developing or regenerating limbs have shown that different limb axes are affected. in regenerating axolotl limbs, serial reduplications in the proximodistal axis are produced. in the developing chick limb bud, mirror-imaged reduplications in the anteroposterior axis are produced. results reported here on rana temporaria limb buds reveal that vitamin a causes both effects to occur. that is, limbs are both serially reduplicated in th ...	1983	6603380
pattern regulation in the anterior half of the embryonically produced symmetrical forelimb of the axolotl, ambystoma mexicanum.	symmetrical forelimbs were created in the axoltl by performing surgery on embryos at stages 32-34. the technique of j.m.w. slack (j. embryol. exp. morphol., 39:151-168, 1977) was utilized. several experiments were then performed to test the ability of these symmetrical forelimbs to participate in pattern formation. when symmetrical limbs were amputated without previous surgery, 58% failed to regenerate. when symmetrical limbs were wounded in the plane of symmetry and permitted to heal for 30 day ...	1983	6613906
gross morphological analysis of limb regeneration in postmetamorphic adult ambystoma.	due to the great disparity between regeneration times for the larval salamander (40 days), axolotl (30+ days), newt (44 days), and adult salamander (155 to 370 days), a staging system was devised so correlative comparisons could be made between regenerative model systems. the sequence was based on two criteria: 1) the stages should be similar to previously reported sequences for the newt, axolotl, and larval salamander, and 2) the stages must be readily recognizable by examination of the externa ...	1983	6614512
size dependence during the development of the amphibian foot. colchicine-induced digital loss and reduction.	localized treatment of the limb buds of the frog, xenopus laevis, and the salamander, ambystoma mexicanum, with the mitotic inhibitor colchicine results in limbs that, when compared with the contralateral control, are smaller in size and have lost skeletal elements. there is a very well defined pattern in terms of what elements are most likely to be lost. for example, frogs that have lost a toe always lose the first toe, while salamanders always lose the fifth. these differences correspond to qu ...	1983	6631320
fibronectin in early amphibian embryos. migrating mesodermal cells contact fibronectin established prior to gastrulation.	the three-dimensional organisation of fibronectin (fn) in early amphibian embryos (ambystoma mexicanum, pleurodeles waltlii) was studied with the use of antibodies against amphibian-fn. immunofluorescence labelling was performed on whole-mount specimens. it was shown that before gastrulation an extensive extracellular network consisting of anastomosed fn-fibrils underlies the roof of the blastocoel prior to the migration of mesodermal cells. initially, fn-fibrils develop radially on the inner su ...	1983	6640612
[nuclear behavior of the growing oocytes of the clawed frog in the cytoplasm of the maturing oocytes of the axolotl].		1983	6641489
spastic mutant axolotl: identification of a phenocopy pathway with implications for the control of axolotl swimming by the vestibulocerebellum.	the spastic mutant axolotl shows abnormal swimming behavior, which includes a preponderance of "embryonic" swimming elements (coils) versus mature swimming elements (sinusoids) and a failure to entrain sinusoids into a prolonged swimming sequence. the mutant also shows anatomical disorganization in the area acousticolateralis and cerebellar auricle, but it is unclear (1) to what extent the behavioral abnormalities are traceable to the vestibulocerebellar defect or (2) how the vestibulocerebellar ...	1983	6643720
the effect of vitamin a on the regenerating axolotl limb.	these experiments describe further investigations into the effects of vitamin a on regenerating limbs. the effects of different retinoids, the time of administration, concentration of vitamin a and histological, autoradiographic and histochemical studies are reported. the most obvious result of vitamin a treatment is to cause proximal elements to regenerate from distal amputation levels, that is to cause serial reduplication of pattern in the proximodistal axis. retinoic acid was the most potent ...	1983	6655434
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
[proliferative activity of the pigment epithelium and regenerating retinal cells in ambystoma mexicanum].	cellular sources of retinal regeneration and proliferative activity of the cells taking part in retina restoration have been studied in axolotls using 3h-thymidine. the cells of ciliary-terminal zone proved to be the main source of retinal restoration. besides these cells, the pigmented cells of the iris inner and outer layers and pigment epithelium cells can take part in this process. morphological stages of retinal regeneration have been established and regular changes in the level of prolifer ...	2006	6657169
[cell satellites and postsatellites in the muscle tissue of the adult ambystoma mexicanum].		1983	6662019
a steady efflux of ionic current predicts hind limb development in the axolotl.	for more than a week prior to the emergence of a hind limb, a steady electric current is driven out of the ventrolateral flank in the immature axolotl, returning through the integument in adjacent regions of the body. a marked peak in the density of this outcurrent could be observed over the exact area of hind limb formation 4 to 6 days prior to its appearance. after a bud projected from the flank, current densities were observed to decrease in magnitude yet localize about the early limb. in abo ...	1983	6663262
isolation of the messenger rna for 8s dna ligase in early developing axolotl egg and its cell free translation.	a new dna ligase activity is expressed when the axolotl eggs enter cleavage. the messenger rna can be labelled by [3h] uridine thereby indicating its de novo synthesis. this new genetic expression is occurring just before cleavage and is the earliest found during amphibian development. the newly synthesized [3h] mrna can be translated in vitro in the rabbit reticulocyte lysate system. the resulting product is a 160 k protein specifically immunoprecipitated with the antiserum directed against 8s ...	1983	6682971
reversal of developmental competence in inverted amphibian eggs.	inverted amphibian embryos were employed for an analysis of pattern formation in early embryogenesis. axolotl (ambystoma) and xenopus eggs were inverted prior to the first cleavage division and permitted to develop upside down to the early gastrulation stage. in both cases the cleavage patterns of the animal and vegetal hemispheres were reversed. by gastrulation, however, developmental arrest began, and no inverted embryos developed beyond neurulation. the state of competence of the animal and v ...	1983	6683745
neurulation in the mexican salamander (ambystoma mexicanum): a drug study and cell shape analysis of the epidermis and the neural plate.	we analysed the neurulation movements in the mexican salamander ambystoma mexicanum. embryos were exposed to colchicine or nocodazole prior to neural fold formation. exposure to these drugs prevented the anterior neural folds from closing. neurulation however proceeded normally in the posterior regions of the embryo. we were unable to find apically constricted cells in the neural plate of colchicine-blocked neurulae. only rounded-up neural plate cells were present (semithin sections). this situa ...	1983	6684145
neural crest cell behavior in white and dark larvae of ambystoma mexicanum: time-lapse cinemicrographic analysis of pigment cell movement in vivo and in culture.	the pattern of migration and motile activity of developing pigment cells of the mexican axolotl, ambystoma mexicanum, were analyzed by time-lapse cinemicrography in vivo and in culture. in vivo, melanocytes of dark (d/-) larvae migrate from dorsal to ventral in a highly directional manner. they are elongated and aligned parallel to the direction of migration. nearly all protrusive activity occurs at their ventral, leading edges. translocation occurs at a mean rate of 0.7 micron/min and involves ...	1984	6699589
neural crest cell behavior in white and dark larvae of ambystoma mexicanum: differences in cell morphology, arrangement, and extracellular matrix as related to migration.	melanocytes of white (d/d) larvae of the mexican axolotl (ambystoma mexicanum) are confined to the dorsal midline of the trunk region, whereas in dark (d/-) larvae they are spread laterally on the flank as well, where they contribute to the normal pigment pattern of the trunk. pigment cell migration in the subepidermal space of white larvae is inhibited by the white epidermis (dalton '50; keller et al., '82). the present scanning electron microscopic study describes a well-defined sequence of ch ...	1984	6699590
genetic mapping in the mexican axolotl, ambystoma mexicanum.	in the mexican axolotl, ambystoma mexicanum, gynogenetic diploids can be produced by suppressing the release of the second polar body in eggs activated with irradiated sperm. if the female is heterozygous for a particular mutation, some of the progeny will be homozygous for the mutation. the proportion depends on the distance from the centromere and can be used to determine the gene--centromere (or gene-kinetochore) distance. the mapping function is based on the neurospora tetrad mapping functio ...	1984	6704787
skin glands in the axolotl: the creation and maintenance of a spacing pattern.	the morphogenesis of skin glands in the larval axolotl is described at the light microscope level. the glands are derived from the epidermis, but are eventually located in the dermis. the glands are non-randomly arranged within the skin and the spacing pattern tends towards a hexagonal array in two dimensions. analysis of the spacing pattern in animals of different sizes reveals that a clear relationship exists between gland size and the distance between glands. occasionally, new small glands ar ...	1984	6716048
[regeneration of isolated skeletal muscle tissue in the axolotl ambystoma mexicanum].		2014	6723509
retinoic acid-induced pattern duplication in regenerating urodele limbs.	the effects of varying doses of retinoic acid on forelimb regeneration in larval ambystoma mexicanum amputated through the wrist joint and in adult notophthalmus viridescens amputated through the basal carpals were compared. in both species, the major effect of retinoic acid was to cause the proximodistal duplication, in the regenerate, of stump segments proximal to the amputation plane. transverse axial duplications (anteroposterior and dorsoventral) occurred in a smaller percentage of cases; t ...	1984	6724131
discovery and initial characterization of a new conditional (temperature-sensitive) maternal effect mutation in the axolotl.	the discovery of a new temperature-sensitive maternal effect mutation in ambystoma mexicanum is described. the new gene (ts-1) was recognized when 100% of the eggs spawned by homozygous females failed to develop past early gastrulation when reared at 25 degrees c. eggs raised at 10 degrees c developed normally to sexual maturity. a temperature-sensitive period during blastulation was identified by a preliminary series of temperature shifts. histologic examination revealed that nuclear abnormalit ...	1984	6734988
different modes of pronephric duct origin among vertebrates.	it is possible to distinguish differences in pronephric duct morphogenesis by using scanning electron microscopy to observe the results of blocking, marking and grafting experiments as well as the normal course of development. here we compare the mode of pronephric duct development in embryos representing three orders of vertebrates: birds (class, aves; order, gallus); frogs (class, amphibia; order, anura); and salamanders (class, amphibia; order, urodela). the axolotl (a urodele) pronephric duc ...	1984	6740242
regional biosynthetic markers in the early amphibian embryo.	a search has been made for regional differences in macromolecular synthesis in the axolotl embryo at a stage when the principal regions have become determined but terminal differentiation has not yet begun. the epidermis of the neurula makes a number of abundant proteins which are not made elsewhere. some of these are identified by immunoprecipitation as cytokeratins (relative molecular masses (mr) 62,59,54,51 and 46 x 10(3)). at the same stage a network of tonofilaments becomes visible by elect ...	1984	6747529
in vitro development of isolated ectoderm from axolotl gastrulae.	the development of ectoderm isolated from the animal pole of axolotl gastrulae is monitored by light microscopy, electron microscopy and analysis of newly synthesized proteins, glycoproteins and glycolipids. when control embryos are undergoing neurulation it is shown that the explants autonomously begin to express epidermal markers and do not express mesodermal markers. however the results suggest that not all the cells become epidermal and electron microscope examination shows that only the out ...	1984	6747530
axial organization of the regenerating limb: asymmetrical behaviour following skin transplantation.	an extensive series of skin grafting operations has been performed to investigate axial organization in the regenerating axolotl limb. semicircular cuffs of skin from either anterior, posterior, dorsal or ventral surfaces were exchanged between right and left limbs thereby creating limbs with double anterior, double posterior, double dorsal or double ventral skin, all with normal internal tissues. both fore and hindlimbs were used at both upper and lower limb levels. following amputation through ...	1982	6754846
carbamoyl-phosphate synthase (ammonia) of rat and axolotl liver: determination of immunological cross-reactivity without purification of the axolotl enzyme.	a method has been developed to establish the degree of cross-reactivity of an antiserum raised against purified carbamoyl-phosphate synthase (ammonia) from adult rat liver, toward a homologous enzyme from another species without purification of the latter enzyme. for that purpose the ratio between enzyme activity and enzyme protein, i.e., the molecular specific activity in crude liver extracts, was determined by two independent methods. when the molecular specific activity was determined by mean ...	1982	6754856
morphogenesis of the regenerating limb blastema of the axolotl: shape, autonomy and pattern.		1983	6828512
regional differences of protein synthesis in the limb regeneration blastema of the axolotl.		1983	6828516
dna ligase in axolotl egg: a model for study of gene activity control.	replacement of the light form of dna ligase (6 s) by the heavy form (8 s) in activated egg of axolotl has been studied as a model for change in genetic activity exerted by the female pronucleus. nuclear transplantation shows that a blastula nucleus is able to govern the replacement of the light ligase by the heavy one. the result is not the same if the grafted nucleus is taken from an androgenetic embryo, devoid of the heavy enzyme. therefore the change in the properties of the female pronucleus ...	1983	6832475
differences between embryos and adults in the plasticity of somatosensory afferents to the axolotl tectum.	the plasticity of somatosensory afferents in the adult axolotl tectum was studied in two ways. first, normal adult axolotls were monocularly enucleated, and second, adult animals which had been monocular since embryogenesis had the tectum contralateral to the remaining eye excised. after a survival time of about one year the brains of these animals were studied electrophysiologically and histochemically. in the enucleated adults, the deprived tectum lacked visual activity, and the acetylcholines ...	1983	6850352
the origin of the mesoderm in an anuran, xenopus laevis, and a urodele, ambystoma mexicanum.	we have investigated whether superficial cells of the blastula contribute to mesodermal structures in the anuran xenopus laevis and the urodele ambystoma mexicanum. the superficial cells alone of late blastulae of both embryos were labelled with bolton-hunter reagent and the embryos were allowed to develop. the progeny of the labelled cells were identified at later stages and the results demonstrate that superficial cells of xenopus blastulae make no significant contribution to the mesoderm, whe ...	1983	6862108
effects of immunization, adult thymectomy and irradiation on axolotl spleen lymphocytes: discontinuous ficoll density gradients analysis.		1983	6873432
the structure of supernumerary limbs formed after 180 degrees blastemal rotation in the newt triturus cristatus.	the structure of supernumerary limbs formed following 180 degrees ipsilateral blastema rotations in the arm of the newt triturus cristatus is analysed. both the skeletal pattern and the muscle patterns are examined. as is the case after comparable experiments in the axolotl (see, for example, maden & mustafa, 12982) the extra limbs which form show a range of anatomies. limbs symmetrical about the dorsal-ventral and anterior-posterior axis are reported as well as some limbs which were part symmet ...	1983	6886592
assessment of mutagenic damage following ethyl methanesulfonate mutagenesis in the axolotl (ambystoma mexicanum).	when male axolots (ambystoma mexicanus) were treated with 100 mg/liter of ethyl methanesulfonate (ems), a dominant lethal effect was obtained. embryonic survival of f1 progeny was most severely reduced between about 50 and 150 days after treatment. dominant lethal lesions probably consist of chromosome breaks that lead to loss of parts of chromosomes or entire chromosomes. the appearance of embryos with a single nucleolus was used to assess this type of damage. the peak incidence of such embryos ...	1983	6886657
muscle and cartilage differentiation in axolotl limb regeneration blastema cultures.	a tissue culture system is described for explants of mesenchyme from ambystoma mexicanum limb regeneration blastemas. explants were cultured on collagen substrate for 3 weeks in minimal essential medium supplemented with the hormones insulin, thyroxine, somatotropin, and hydrocortisone, plus beef embryo extract (ee), 2%. this medium supported extensive cell migration onto the substrate followed by cell proliferation and differentiation of both cartilage matrix and myotubes. cultures on plastic s ...	1983	6886662
experimental studies on a lethal gene (t) in the mexican axolotl, ambystoma mexicanum.	in the mexican axolotl, ambystoma mexicanum, the developmental mutation lethal t is inherited as a simple mendelian recessive. mutant larvae failed to feed and died, on the average, 17 days after hatching. unfed wild-type larvae died an average of 23 days after hatching. by 15 days, forelimb development had progressed further in the wild type; a cartilaginous scapula and humerus were present, but no cartilage was seen in the mutant limb. histological examination indicated that the visceral carti ...	1983	6886665
cell commitment and gene expression in the axolotl embryo.	in the axolotl embryo the somitic mesoderm passes through a reversible and then an irreversible phase of commitment with respect to its later differentiation into muscle. we show that the commencement of alpha-actin synthesis and the first appearance of thin myofilaments occur at the the same developmental stage as the transition between these phases. in intact embryos beta-and gamma-actin are made at all stages of development and in all tissues. alpha-actin, however, first appears at the late h ...	1980	6893572
two actin variants in developing axolotl heart.		1981	6894432
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
lysophosphatidyl choline facilitates labeling of cns projections with horseradish peroxidase.	previously, it has been difficult to label sensory terminations in the cns by back-filling peripheral sensory nerves with horseradish peroxidase (hrp), apparently because the amount of hrp transported along the axons is insufficient. labeling of central sensory projections in axolotls and frogs can be improved by agents known to disrupt membranes. of those tested, l-alpha-lysophosphatidyl choline is the most effective. the addition of this detergent ot the hrp solution dramatically increases bot ...	1980	6967137
on spontaneous skin tumours in amphibia.	in 7 from 320 rana temporaria grass frogs and 16 from 978 rana ridibunda pond frogs, the 31 and 47 spontaneous skin tumors respectively, were observed. the tumors were represented by cystadenopapillomas and adenocarcinomas, and developed from epithelium of skin mucous glands. the spontaneous pigment tumors (melanophoromas) were found in 2 axolotls ambistoma mexicanum. these tumors developed from hyperplastic melanophores in pigment spots and focal proliferations of melanophores located deeply in ...	1980	6969862
thymus dependency in anti-trinitrophenyl (tnp) binding responses in the spleen of ambystoma mexicanum. effects of thymectomy and anti-thymocyte serum treatments.		1981	6970685
an atlas of notochord and somite morphogenesis in several anuran and urodelean amphibians.	a scanning electron microscopic, comparative survey of notochord and somite formation including some details of change in cell morphology and arrangement, was made of selected stages of two species of anuran amphibians (xenopus laevis and rana pipiens) and two species of urodeles (ambystoma mexicanum and pleurodeles waltlii). the ectoderm or neural plate was removed from fixed embryos and the dorsal aspect of the developing notochord and somite mesoderm was photographed. micrographs of comparabl ...	1980	6971322