Publications

spontaneous release of transmitter from 'repressed' nerve terminals in axolotl muscle.		1977	18677
electrophysiological experiments on the mechanism and accuracy of neuromuscular specificity in the axolotl.	the supracoracoideus muscle of the axolotl shoulder girdle is innervated by two nerves, the supracoracoideus nerve (sc) supplying most of the muscle and the posterior supracoracoideus (psc) supplying the posterior corner. all the muscle fibres are multiply innervated and at the border between the two innervations many muscle fibres, when penetrated by a microelectrode, show junction potentials from both nerves. in such cases one junction potential is often very small, below the threshold for exc ...	1977	19787
[effect of prolactin on mucous epidermal cells in the intact and hypophysectomized axolotl].		1975	54279
an autoradiographic study of optic fiber projections from eye grafts in eyeless mutant axolotls.		1977	67046
morphological and functional aspects of the arrangement of connective tissue and muscle fibres in the tail of the mexican axolotl, siredon mexicanum (shaw) (amphibia, urodela).	in the lateral musculature of the axolotl tail a multipennate arrangement of muscle fibres is found in the 3rd postanal myomere and all following myomeres. this arrangement appears in larval stages as soon as the myomeres concerned are fully differentiated. within a myomere a uniform degree of contraction of the muscle fibres may be achieved either by helical arrangement as seen in teleosts, by diminishing fibre length in medial direction or by a combination of both phenomena. the relation betwe ...	1977	67739
on the differentiation of prospective ectoderm to a ciliated cell pattern in embryos of ambystoma mexicanum.	the differentiation of the ectoderm in ambystoma mexicanum (harrison stage 26--27) was examined under in vivo and in vitro conditions by scanning electron microscopy under different experimental conditions. about one out of three flank epidermal cells was found to be ciliated in the undistrubed or control embryos. the shape of ciliated cells in the explants from the animal region was only slightly affected. in no case was it possible to find two adjacent ciliated cells, implying that these cells ...	1977	73569
[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
induced metamorphosis in ambystoma mexicanum: lack of effect of triiodothyronine on tissue or blood levels of thyrotropin-releasing hormone (trh).		1998	105962
an sem and tem study of suppression of eye development in eyeless mutant axolotls.	morphology of the primary optic rudiment of normal eyed and mutant eyeless (e/e) axolotl embryos was studied at light. tem and sem levels. the presumptive eyeforming region of eyeless embryos differs from that of normal embryos in several important respects including premature formation of basal lamina, separation from overlying ectoderm by mesenchyme cells and persistence of granules in the interspace surrounding the optic anlage into relatively late developmental stages. these differences sugg ...	1979	110173
[experimental studies on the symmetry reaction of axolotl oocytes and eggs: factors affecting the early appearance of the grey crescent following heat shock].	a heat-shock (36.8 degrees c for 10 min.) can induce the immediate appearance of the grey crescent in a high proportion of freshly laid fertilised or artificially activated axolotl eggs, but only if that shock occurs within 1 h 30 min. following deposit of eggs (at 18 degrees c) and if eggs are not dejellied. on non-activated virgin eggs, the heat-shock is efficient during at least 3 hrs. this symmetry reaction can be induced on in vitro artificially matured oocytes, still protected by follicula ...	1979	111864
delayed hypersensitivity in ambystoma mexicanum.		1979	113261
[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
stretch receptors in urodele limb muscles.	non-encapsulated, fine beaded nerve endings were found histologically on some muscle fibres in a number of limb muscles in newts and axolotls. they were present in newt muscles that had been chronically de-efferented, and in which no efferent activity survived, and were therefore likely to be sensory. they were located only on muscle fibres on or near the outside surface of the muscle. these small-diameter muscle fibres were characterised histochemically by low lipid, sdh and phosphorylase conte ...	1976	129283
[oxygen consumption and cytochrome oxidase activity of muscle tissue from the limbs of axolotls following restoration of regenerative capability suppressed by x-ray irradiation].	the intensity of oxygen consumption and the activity of cytochrome oxidase have been studied in the homogenate, mitochondria and nuclei of the limb muscle tissue in axolotls after the suppression of regenerative ability by x-irradiation and its experimental restoration. under the suppression of regenerative ability, the oxygen consumption was inhibited. the cytochrome oxidase activity in the homogenate and mitochondria decreased and in the nuclei remained at the same level or even increased as c ...	1975	175338
[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
three muscle fibre types in the axial muscle of axolotl (ambystoma mexicanum shaw): a quantitative light- and electron microscopic study.	morphometric analysis by light microscopy of p-phenylene-diamine stained semithin sections of axolotl tail muscle revealed differences in the cross-sectional area of the fibres and in the number of mitochondria and of lipid inclusions per fibre, and indicated the presence of three distinct types of fibres. the tripartition was found to be statistically highly significant. representative fibres from each group established by light microscopic morphometry were subjected to an ultrastructural morph ...	1996	178448
the intracellular localization of carbamoyl-phosphate synthase (ammonia) activity in the liver of the mexican axolotl, ambystoma mexicanum (shaw).		1976	183934
the hormonal regulation of urea excretion in the mexican axoloti (ambystoma mexicanum cope).		1977	188719
the formation and regression of synapses during the re-innervation of axolotl striated muscles.	1. a study has been made of the formation and regression of synapses formed by spinal nerves 16 and 17 in axolotl hind-limb flexor muscles following the severing of nerve 16, using histological, ultrastructural and electrophysiological techniques. 2. axolotl hind-limb flexor myofibres possessed 'en plaque' end-plates from either spinal nerve 16 or 17 or both at intervals of about 1000 micronm along their length; the myofibre's length constant was about 700 micronm allowing electrophysiological o ...	1977	191597
ionic mechanism for the generation of horizontal cell potentials in isolated axolotl retina.	the ionic mechanism of horizontal cell potentials was investigated in the isolated retina of the axolotl ambystoma mexicanum. the membrane potentials of both receptors and horizontal cells were recorded intracellularly while the ionic composition of the medium flowing over the receptor side of the retina was changed. the membrane potential of the horizontal cell is highly depender side of the retina was changed. the membrane potential of the horizontal cell is highly dependent on the extracellul ...	1988	202664
suppression of foreign innervation in axolotl muscle may not be dependent on juxtaposition of native and foreign nerve terminals.	the posterior supracoracoideus nerve of the axolotl, ambystoma mexicanum, was induced to make synapses outside its normal muscle territory. muscle fibres with inputs from both native and foreign nerves were studied during the period of suppression of foreign transmission and in only 8% of fibres were foreign and native terminals found within 120 micrometer of each other. a combined cholinesterase/silver staining technique revealed non-innervated endplates in foreign-innervated fibres just prior ...	1979	223086
re-innervation of axolotl limbs. i. motor nerves.		1975	237287
re-innervation of axolotl limbs. ii. sensory nerves.		1975	237288
multiple melanomas in the axolotl ambystoma mexicanum.	multiple melanophoromas in the axolotl ambystoma mexicanum were characterized by cell anaplasia and polymorphism. pigment spots may be the first stage of tumor development.	1979	286820
target recognition in neurogenesis: formation of the mauthner axon cap.	to learn whether presence of a specific neuron, the mauthner (m) cell, is required for the organization, during embryogenesis, of an associated synaptic neuropil, the m-axon cap, m-cell precursors were experimentally deleted in embryos of the zebra fish (brachydanio rerio) and the axolotl (ambystoma mexicanum). examination of early larvae revealed that in about half of the cases m-axon caps were present in the absence of the corresponding m-cells. the locations and structures of such caps were a ...	1979	291997
quantitive studies of the reactions to horizontal angular accelerations in axolotls. ii. head-turning reflexes in animals with a supernumerary pair of labyrinths.	in axolotls (ambystoma mexicanun) the labyrinths and the associated parts of the medulla were doubled artificially. in these so-called tandem-heads the vestibular afferent fibres from both labyrinths on one side united within the medulla to form common bundles. the head-turning reflexes following impulse acceleration and during long-lasting acceleration were measured quantitatively and compared with those for normal animals. the form and the time-course of the reactions were almost identical in ...	1977	300773
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
high density cell water in amphibian eggs?	the exchange of isotopic water, 2h2o and h2(18)o has been studied in amphibian eggs. the experiments were carried out with ovarian and body cavity eggs of rana temporaria and unfertilized eggs of ambystoma mexicanum. the cytoplasmic diffusion coefficient for h2(18)o was found to be 4.6 x 10(-6) cm2/s, somewhat higher than that for 2h2o, 3.4 x 10(-6) cm2/s. the total change in reduced weight, delta rw, during the isotope experiments was compared with the total amount of water in the egg cell, m. ...	2000	317089
role of thyroid hormones in the normal and glucocorticosteroid hormone-induced evolution of carbamoyl-phosphate synthase (ammonia) activity in axolotl liver.	1. in axolotl liver, the activity of carbamoyl-phosphate synthase (ammonia), expressed per mg liver protein, decreases to a minimum at 5 months of age, then increases to a maximum at 8 months of age which is followed by a decrease again. the initial decrease between 3 and 5 months of age appears to be largely due to an increase in non-carbamoyl-phosphate synthase protein and the following increase between 5 and 8 months of age to a relative increase of carbamoyl-phosphate synthase protein. 2. tr ...	1978	318276
distribution and homologies of subunits in the ldh isoenzyme pattern of urodeles.	1. the subunit distribution and homologies of ldh isoenzymes are investigated in the species triturus vulgaris, cristatus, alpestris and helveticus, and ambystoma mexicanum by means of immunoprecipitation and starch gel electrophoresis. 2. fresh tissue extracts contain the following patterns: (a) trit. vulgaris--two isoenzymes: the m4 and h4 tetramers. no hybrid formation is observed between h and m subunits. (b) trit. cristatus--two isoenzymes: the m4 and h4 tetramers. occasional hybrid formati ...	1978	318283
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
the role of grafted skin in the regeneration of x-irradiated axolotl limbs.		1977	320068
effect of temperature on transplantation immunity in ambystoma mexicanum.	juvenile and mature neotenous ambystoma mexicanum received allogeneic and xenogeneic skin transplants. rejection times for 1st-set, and 3rd-set grafts were noted at 21 degrees c, and for axolotls placed in a cold-room at 7 degrees c 7 h post-grafting, 1 week post-grafting and 2 weeks post-grafting respectively. in all cases graft-rejection was chronic; 2nd and 3rd-set grafts were rejected progressively more rapidly than 1st-set grafts. an important temperature-sensitive event occurs during the 1 ...	1978	357221
identification by immunofluorescence of prolactin- and somatotropin-producing cells in the pituitary gland of the mexican axolotl (ambystoma mexicanum, shaw).	the indirect immunofluorescence procedure was used to identify prolactin (lth)-and somatotropin (sth)-producing cells in the pituitary of the mexican axolotl. histological staining techniques were employed to corroborate immunocytological results. the lth cells are large, orange-staining cells (acidophils 1) distributed in the posterior two-thirds of the pars distalis. the sth cells are small, erythrosinophilic elements (acidophils 2) principally concentrated in the dorsal part of the pars dista ...	1978	365348
myogenesis and inductive processes during heart development in mexican axolotls (ambystoma mexicanum).		1978	367464
regenerative responses in larval axolotl limbs with skin grafts over the amputation surface.	complete flaps of whole skin over the amputation surface of larval axolotl limbs did not prevent dedifferentiation, dna synthesis, and mitosis. however, even by two weeks, insufficient cell division had occurred for blastema formation. in about 50% of the cases, small areas of wound epidermis formed over the amputated tip of the radius or ulna. at two weeks after amputation, mitotic figures and dedifferentiated cells which incorporated h3-thymidine were predominantly located in the vicinity of t ...	1979	381569
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
experimental studies on a mutant gene, a, causing albinism in the axolotl, ambystoma mexicanum.		1978	414944
axon reflexes in axolotl limbs: evidence that branched motor axons reinnervate muscles selectively.		1979	428494
morphogenetic interactions occurring between blastemas and stumps after exchanging blastemas between normal and double-half forelimbs in the axolotl, ambystoma mexicanum.		1979	437319
normal anterior endoderm corrects the heart defect in cardiac mutant salamanders (ambystoma mexicanum).	recessive mutant gene c in axolotl embryos results in an absence of heart function. normal (+/+) anterior endoderm cultured with mutant (c/c) hearts totally corrects the defect.	1979	441740
development of synaptic connections between different segmental motoneurones striated muscles in an axolotl limb.		1979	446887
duplicated axolotl regenerates.	three series of palette stage regenerates were prepared by amputating both arms of juvenile axolotls in the mid-forearm, above the elbow, or close to the shoulder. within each series, excised regenerates were replaced in their original orientation (as a control) or rotated at 90 degrees intervals about the proximodistal axis, or were transplanted to the contralateral arm with identical rotations. control grafts occasionally caused the formation of a single extra digit. all experimental rotations ...	1979	448271
chloride-dependent sodium transport in the skin of ambystoma mexicanum [proceedings].		1979	458718
maintenance of growth- and thyroid-stimulating properties of ectopic pituitaries in the mexican axolotl (ambystoma mexicanum).		1979	467973
the regression of synapses formed by a foreign nerve in a mature axolotl striated muscle.	a study has been made of the factors which determine that the terminals of a foreign flexor nerve at synaptic sites in a unrodele extensor muscle regress on return of the original extensor nerve. the quantal content (m) of the endplate potential (epp) at flexor nerve terminal synapses, during innervation of a previously denervated extensor muscle, increased in about 8 weeks to reach the same size as at normal extensor nerve terminals; the same time was taken for m to reach normal size at extenso ...	1979	487102
allopurinol-induced melanism in the tiger salamander (ambystoma tigrinum nebulosum).	the enzyme, xanthine dehydrogenase (xdh), has been examined in ambystoma tigrinum nebulosum with respect to its role in pigmentation. it now seems probable that the melanoid gene (m) either codes directly for xdh or is somehow intimately connected with the normal function of this enzyme. inhibition of xdh using the drug, allopurinol, results in animals which appear to be phenocopies of melanoid mutants as described for the mexican axolotl (ambystoma mexicanum). the effects of allopurinol in term ...	1979	490138
steroidogenesis in axolotl testis. histochemistry of two major enzymes related to cell type, spermatogenesis, and substrate.		1979	499762
embryo surface morphology during post-gastrula development of the frog, bombina orientalis, as revealed by scanning electron microscopy.	to further study the morphology of the developing amphibian embryo, and to provide a basis for the characterization of abnormal embryogenesis, surface features of the bombina orientalis embryo during post-gastrula development were examined with the scanning electron microscope. ciliated cells similar to those reported for rama pipiens and ambystoma mexicanum were observed in the epidermis. epidermal secretory cells displaying large numbers of exocytotis apertures become prominent at the early ta ...	1996	500492
positional information in the forelimb of the axolotl: experiments with double-half tissues.		1979	527764
the formation of muscles in regenerating limbs of the newt after denervation of the blastema.	the purpose of this experiment was to examine the relationship, if any, between nerve fibers and the formation of muscle pattern in the regenerating amphibian limb. during embryogenesis, nerve fibers grow into the limb bud at the time when the common muscle blastemas subdivide into individual muscle primordia, whereas in regeneration nerve fibers are always present. in order to learn whether or not the muscle pattern could be laid down in the absence of nerves we amputated 58 limbs of newts (not ...	1979	528874
development of the sympathetic system in the mexican axolotl, ambystoma mexicanum.		1977	557011
microtubule proteins in axolotl eggs and developing embryos.		1977	559603
preferential expression of the maternal allele for alcohol dehydrogenase (adh) in the amphibian hybrid ambystoma mexicanum (axolotl) x ambystoma texanum.		1977	561728
evidence for a dna ligase change related to early cleavage in axolotl egg.	a definite change in the forms of dna ligase appears when the axolotl egg enters cleavage. sucrose gradient and phosphocellulose chromatography show that the a 6s form of dna ligase exists before division, i.e. in unfertilised and fertilised egg, and a 8.2s form is present at the first division. n-ethylmaleimide sensitivity and heat stability are different for the two forms. the possible significance of this early change is discussed.	1979	574805
dna synthesis after polyspermic fertilization in the axolotl.	cytological and autoradiographic studies were done to investigate the cytoplasmic control of dna synthesis under conditions of physiological polyspermy. the dna synthetic phases of the egg, principal sperm and accessory sperm nucleic were determined and correlated with nuclear morphology and develpmental fate. results show that accessory sperm nuclei undergo morphological transition to pronuclei. their dna synthetic phase is the same as that of the principal sperm nucleus. hence accessory sperm ...	1979	574896
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
the role of schwann cells in paradoxical regeneration in the axolotl.	the experiments described here examine further the conditions under which paradoxical regeneration occurs and provide support for the hypothesis that a proximal migration of schwann cells is responsible for the phenomenon. when only the hand is shielded from irradiation and the limb is denervated, amputation through the forearm or upper arm sometimes results in regeneration. the effects of variation in the time interval between denervation and amputation, the level of amputation and the method a ...	1977	591863
axolotl stretch reflex [proceedings].		1977	599458
artificial neural induction in amphibia. i. sandwich explants.	1. embryonic tissues (ectoderm, neural plate) of ambystoma mexicanum and tritus were killed with hot water and implanted into ectoderm sandwiches. they induced the ectoderm to form neural tissue, lentoids and unspecialized epidermis. neural tissue always showed retina character. egg pigment was eliminated and gathered at the outer retinal surface or in the centre of rosettes. neural crest cells like mesenchyme or melanophores were completely lacking, retinal pigment did not develop. 2. the thus ...	1977	603082
a lethal mutant gene in the mexican axolotl.	gene ph was discovered in a wild-type axolotl male received from mexico city. larvae homozygous for this gene become recognizable by their lighter color at hatching or shortly after. the development of their forelimbs is retarded, and all limbs are of subnormal length because of the reduction in length of their long bones. many affected larvae die without feeding, and very few survive beyond their third month. at death, older larvae usually show abnormalities of the renal system, edema, ascites, ...	2006	608947
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
[differentiation behavior of the mesodermal germinal sone of differently old pregastrulation stages of ambystoma mexicanum. cultivation of untreated and lithium-treated isolates].	isolates from the dorsal, lateral and ventral area of the marginal zone are showing differentiation capacities already in the stage of early morula. the composition of the differentiation pattern alters: ecto- and mesodermal tissues are realized until the late morula. beyond these, endodermal structures are visible with the stage of early blastula. after a mild li treatment of the isolates the differentiation pattern of the marginal zone shows significant modifications. ectodermal organs are reg ...	1977	614737
the occurrence of supernumerary limbs following blastemal transplantation in the regenerating forelimb of the axolotl, ambystoma mexicanum.		1978	620870
experimental studies on two mutant genes, r and x, in the mexican axolotl (ambystoma mexicanum).		1978	620874
the pattern of innervation of a polyneural muscle: axolotl iliotibialis.	the pattern of innervation on individual iliotibialis muscle fibres from axolotl (ambystoma mexicanum) has been investigated histologically and electrophysiologically. these polyneural fibres were found to be innervated on average at five end plate sites. the sites were distributed irregularly along each fibre. average end plate length was found to be approximately 70 micrometer. most end plates were separated by less than 1000 micrometer; 26% by less than 150 micrometer; the average separation ...	1978	627010
studies on the effects of bleaching amphibian rod pigments in situ. i. the absorbance spectra of axolotl and tiger salamander rhodopsin and porphyropsin.		1978	639883
studies on the effects of bleaching amphibian rod pigments in situ ii. the kinetics of the slow bleaching reactions in axolotl red rods.		1978	639884
supernumerary limbs in the axolotl.		1978	643082
[cell proliferation study at various stages of gastrulation in axolotl embryos].	a study of cell proliferation in different regions of axolotl embryos has shown a rather uniform distribution of the s phase and mitotic indices in the animal half of the early and midgastrulae. the dorsal blastoporal lip is characterized by a very low s phase index as compared with the other regions of the embryo.	1978	643249
interaction between foreign and regenerating axons in axolotl muscle.		1978	647386
cinematographical study of cell migration in the opened gastrula of ambystoma mexicanum.	the migration of inner marginal cells was studied in the ambystoma gastrula, using scanning electron micrography and time-lapse cinemicrography. scanning electron micrographs of gastrulae which were fixed while intact revealed that the migrating cells have flattened lamellipodia at their anterior end and a rounded cell body, which can sometimes be seen to be attached to a neighbouring cell by a slender posterior process. films of opened gastrulae showed actively moving cells, with the same featu ...	1978	650142
developmental studies on an apparent cell-lethal mutant gene-ut-in the mexican axolotl, ambystoma mexicanum.	the discovery of a new mutant gene in stocks of the mexican axolotl derived from breeding stock of the hubrecht laboratory, the netherlands, is described. the gene appears to be a simple recessive and displays complete penetrance. ut/ut larvae develop normally through hatching, but begin to lag in growth and display characteristics defects in gill and limb formation shortly thereafter. the results of parabiosis of normal and mutant embryos, as well as embryological transplants of mutant limb and ...	1978	657276
the failure of double-half forelimbs to undergo distal transformation following amputation in the axolotl, ambystoma mexicanum.	although capable of initiating early regenerative responses, axolotl forelimb stumps which are composed of double-half limb tissues fail to undergo the events that normally lead to the replacement of missing parts. in the present study, the posterior halves of right forelimbs were exchanged with the anterior halves of left forelimbs, or the dorsal halves of right forelimbs were exchanged with the ventral halves of left forelimbs. forelimbs were amputated through the graft region 30 days after gr ...	1978	660138
regeneration of mirror symmetrical limbs in the axolotl.	mirrow symmetrical, double posterior limbs were produced by two types of operations on tailbud embryos of the axolotl, ambystoma mexicanum. when the limbs had grown to maturity, they were amputated and a study was made of the structures which regenerated in their place. the majority of the regenerates were also reduplicated, although a significant minority showed other types of symmetry. reduplicate symmetry was often conserved following several amputations, but the number of skeletal elements p ...	1978	667926
studies on the effects of bleaching amphibian rod pigments in situ. iii. linear dichroism in axolotl red rods before and during bleaching.		1978	668823
studies on the effects of bleaching amphibian rod pigments. iv. photoresponses recorded intracellularly from axolotl red rods following bleaching flashes.		1978	668824
regulation of the mauthner cell following unilateral rotation of the prospective hindbrain in axolotl (ambystoma mexicanum) neurulae.		1978	679039
the differentiation-pattern in dependence of the proportion between inducing and induced cells studied on gastrula-ectoderm of ambystoma mexicanum.	the dependence of the differentiation-pattern of competent amphibian ectoderm on the proportion of inducing and induced material was studied. to do so different masses of licl-treated tissue were combined with a constant mass of untreated material. licl-treated isolates corresponding in size with the treated portions in the combinations served as controls. the experiments seem to show at least three factors responsible for the differentiation-pattern of the combinations: the number of inducing c ...	1978	732361
mesodermalization of amphibian gastrula ectoderm in transfilter experiments.	transfilter experiments were carried out with competent gastrula ectoderm of triturus vulgaris and ambystoma mexicanum as the reacting materials and blastoporal lip, alcohol-treated bone marrow and archenteron roof as the inducing materials, it was shown that a mesodermal inducing substance is able to penetrate nuclepore filters of different pore sizes (3.0, 1.0, 0.4, 0.2 micrometer). the degree of mesodermal differentiations depends on the reacting materials, the inductors and the filters which ...	1978	732366
neurotrophic control of the cell cycle during amphibian limb regeneration.	it is shown here that amputated and denervated limbs of larval axolotls dedifferentiate and a proportion of the cells released undergo dna synthesis and mitosis. when the limb is denervated prior to amputation fewer cells go through the cell cycle, implying the existence of a pool of trophic factor in the limb. recent work has demonstrated that denervated blastemal cells accumulate in the g1 phase of the cycle. these results strongly argue against the theory that the trophic factor controls the ...	1978	744947
the effect of healing time on the proximodistal organization of double-half forelimb regenerates in the axolotl, ambystoma mexicanum.		1978	751844
[morphogenesis of the anterior limb primordium and its histochemical aspects in the pleurodele and the axolotl].	in both species, the primary mesodermal blastema of the forelimb bud derives from a regional proliferation of somatopleural cells under the ectoderm. a cellular sheet of somitic origin invades the limb blastema early. morphological and histochemical changes suggest the establishment of early ecto-mesodermal interactions in the young limb bud.	1975	808278
[evolution of xenografts of embryonic gonads and juvenile ovaries from ambystoma mexicanum shaw, transplanted into triturus alpestris laur].	gonad primordium of ambystoma mexicanum when grafted at tail-bud stage on triturus alpestris is indefinately tolerated. testis or ovaries derived from those grafted embryonic gonads follow their differentiaion and reach sexual maturity. axolotl juvenile ovaries transplanted in triturus alpestris are also tolerated; the ovocytes achieve the entire vitellogenesis but are not able to be laid.	1975	809199
[activities of protein synthesis during the development of lethal nucleocytoplasmic hybrids obtained by nuclear graft between ambystoma mexicanum shaw and ambystoma dumerilii duges (amphibia, urodeles)].	a comparative study of proteinograms and zymograms (ldh, mdh) has been carried out at different ontogenic stages, in ambystoma mexicanum (a.m.), ambystoma dumerilii (a.d.) and nucleocytoplasmic hybrids 2 n a.d/cytoplasm am. it appears that 2 n a.d. nucleus, grafted in a.m. cytoplasm expresses only a part of its potentialities, which could account for lethality of the nucleocytoplasmic hybrids.	2014	809209
[demonstration of rna synthesis during segmentation in the axolotl embryo].	study of the incorporation of 3h-uridine in cleaving embryo of axolotl has shown a nuclear rna synthesis during the period of synchronous cleavage (6th cycle) as well as after the onset of asynchronous divisions (9th or 10th cycle). in the early development of the axolotl, the extent of the transcription phase looks to be an essential element of the quantitative control of gene activity.	1975	811409
[transplantation into the blastocoel of pleurodeles waltlii michah., of blastomers isolated from blocked blastulae obtained from interspecific nuclear transplants between ambystoma mexicanum shaw. and ambystoma dumerilii dugès (urodele amphibians)].	ectodermic blastomeres from arrested nucleocytoplasmic blastulae obtained by nuclear graft between ambystoma mexicanum (a. m.) and ambystoma dumerilii (a. d.), are transplanted in the blastocoele of recipient pleurodeles waltlii blastulae. histo-autoradiographic analysis shows that hybrid cells have cellular affinities and multiplication capacities very different from normal ambystoma mexicanum blastulae isolated cells. the possibility that a revitalisation of lethal blastomeres can occur should ...	1975	813905
[development of gonads transplanted homoplastically in limbs of sexually immature axolotls].	graft development depends on sexual maturation of the host. three successive steps in development of transplants have been demonstrated: somatic growth, gonial division and germinal maturation. sexual maturity occurs earlier in females than in males.	1976	821644
developmental interactions in the growth and branching of the lateral dendrite of mauthner's cell (ambystoma mexicanum).		1977	838120
factors influencing ovulation in the mexican axolotl as revealed by induced spawnings.	axolotl females may be induced to spawn by injecting them with small doses of fsh prior to mating. data on the different categories of spawnings obtained by this procedure have established the following points. (1) spawnings of injected females completely without fertile eggs are small (173 eggs average). courtship occurred in some of the matings (spermatophores found) but not in all. spawnings of injected but uninseminated females re-mated with a second (or third) male, not becoming inseminated ...	1977	845578
the development of monamine-containing neurons in the brain and spinal cord of the salamander, ambystoma mexicanum.	the distribution of monoamine-containing neurons in the cns of the developing and adult axolotl, ambystoma mexicanum, has been investigated using the histochemical fluorescence technique of falck and hillarp combined with microspectrofluorimetry. the earliest catecholamine-containing neurons to be detected are located in the ventral ependymal zone of the spinal cord at the time of hatching (stage 41). between stages 43 and 46, catecholamine fluorescence can be detected in neurons in the followin ...	1977	856887
evidence for abnormal heart induction in cardiac-mutant salamanders (ambystoma mexicanum).	homozygosity for simple recessive gene c in axolotl embryos results in the absence of a heartbeat. gene c alters the morphology of the mutant anterior endoderm - the primary heart inductor.	1977	860120
the timing of morphogenetic events in the regenerating forelimb of the axolotl, ambystoma mexicanum.		1977	863102
fiber counts of regenerating peripheral nerves in axolotls and the effect of metamorphosis.	counts have been made of myelinated and unmyelinated fibers in the sixteenth nerve root of the axolotl, before, during and after regeneration following nerve section. there is no loss of myelinated fibers. many collateral sprouts are formed and eventually withdrawn. regeneration during metamorphosis is similar but there is more sprouting. there is no fiber loss from cut nerves in metamorphosis. this suggests that rising thyroid hormone levels are not in themselves detrimental to nerves without p ...	1977	864039
quantitative studies of the reactions to horizontal angular accelerations in axolotls. i. the head-turning reflexes of normal animals.	1. artifically metamorphosed axolotls were exposed to both brief (impulse) and long-lasting horizontal angular accelerations on a turn-table. the animals responded with a head-turning reaction. 2. the general course of the reaction to impulse acceleration was independent of stimulus intensity. the velocity of the head movement first increased to a maximum exponentially and then decreased in a negative exponential manner. stimulus intensity had a linear relationship to the mean maximum velocity a ...	1977	870596
[desynchronization of cell division during the early development of the axoloty, loach and salmon].	patterns of a relative measure of asynchrony r of the cell population have been studied by means of a mathematical model of the kinetics of cell population which allows to follow the distribution of cells by the mitotic cycle phases in time. the application of the criterion r for the analysis of the patterns of desynchronization of cell divisions in the early embryogenesis of axolotl, loach and salmon has shown, that, unlike the smooth change of the asynchrony measure in the model populations wi ...	1977	882238
[heat production in the early stages of axolotl growth according to direct and indirect calorimetry findings].	the level of energetic metabolism of the growing axolotls was studied by the methods of direct and indirect calorimetry. just after the hatching the heat production of the larvae calculated by the gas exchange exceeds markedly the level of heat production measured by the calorimeter. during the subsequent growth the level of heat production changes as a transitional process, so that therafter indirect calorimetry gives constantly higher values of energetic metabolism than direct one.	1977	882247
experimental studies on a mutant gene (p) causing premature death of ambystoma mexicanum embryos.	the premature death (p) mutation is a recessive lethal, which, in the homozygous condition, gives rise to a complex of abnormalities. the mutant embryos develop only to stage 37, at which time disintegration of superficial tissue begins. many of the abnormalities observed in sections of the stage-37 mutant embryo are related to its failure to establish a functioning circulatory system, or to the resulting edema and/or ascites that distend the abdomen and flanks. there are, however, abnormalities ...	1977	886253
determination of anteroposterior polarity in the axolotl forelimb by an interaction between limb and flank rudiments.	1. it is shown that the mesoderm in the prospective forelimb-bud of the axolotl embryo is thickened and divided into somatic and splanchnic layers, while that of the flank is thinner and divided. the first sign of the limb-bud itself appears at stage 38. 2. a whole, a half or a third of a limb rudiment can develop into a normal or reduplicated limb when transplanted to the flank. 3. an anterior half of a limb rudiment fails to develop when transplanted to the head but will do so if accompanied b ...	1977	886254
control of anteroposterior pattern in the axolotl forelimb by a smoothly graded signal.	(1) it is shown that the number of cartilage elements in an experimentally produced reduplicated limb depends on the width of competent tissue between pieces of flank tissue. (2) seventy well formed reduplications were examined on the assumption that the difference in the number of elements between them results from small differences in graft position. (3) all the reduplications are symmetrical along their entire length. (4) all possess the most posterior structures at both edges with other elem ...	1977	886255