| comparative analysis of amphibian somite morphogenesis: cell rearrangement patterns during rosette formation and myoblast fusion. | detailed sem observations of the changes in cellular morphology, arrangements, and contacts that occur during the process of somite formation were made in two species of urodele amphibians, ambystoma mexicanum and pleurodeles waltlii, and one species of anuran amphibian, rana sphenocephala. after fixation, embryos were fractured transversely, horizontally, and parasagittally, and the intrasomitic cellular arrangement pattern was examined with the sem. it was found that ambystoma and pleurodeles ... | 1981 | 7338706 |
| the ability of localized implants of whole or minced dermis to disrupt pattern formation in the regenerating forelimb of the axolotl. | the ability of localized grafts of dermis to alter pattern formation in the regenerating limb of the axolotl was studied. longitudinal pieces of skin (1/4 of circumference of the limb) were removed from either the anterior or the posterior surface of the upper forelimb. epidermis was removed by immersion in versene followed by mechanical stripping. the resulting dermis was cross transplanted directly beneath the skin on the opposite side of the limb from which it originated. after 5 days of heal ... | 1981 | 7034520 |
| [model studies of the effect of structural changes in cleaving embryo on electrical parameters of cellular interactions]. | two models of the embryo developing from one initial cell by cleavage division are considered. equivalent electrical schemes were constructed, changes in electrical coupling coefficient (kec) and input resistance (ri) of the embryos during cleavage were estimated. considerable influence of cleavage-related changes of membrane parameters on kec and ri appears at the first five--ten cleavages and essentially depends on the ratio of contact and incontact membrane resistances. a comparison of the es ... | 2007 | 7317491 |
| enzymes involved in dna replication in the axolotl. ii. control of dna ligase activity during very early development. | | 1981 | 7286414 |
| enzyme involved in dna replication in the axolotl. i. analysis of the forms and activities of dna polymerase and dna ligase during development. | | 1981 | 7286413 |
| probability aspects of supernumerary production in the regenerating limbs of the axolotl, ambystoma mexicanum. | the applicability of deterministic models, and in particular the polar co-ordinate model of french, bryant & bryant (1976), to the regenerative process has been investigated by performing ipsilateral blastemal rotations of varying angle on the fore and hind limbs of the axolotl. the results show that the frequency of supernumerary production rises with increasing angle to reach a peak at 180 degree and then falls off more rapidly, giving rise to an asymmetric distribution curve. the position of ... | 1981 | 7334295 |
| behavioral and electrophysiological study of cutaneous trigeminal nerves in axolotls. ii. the effects of cross-anastomosis of nerves. | | 1981 | 7272781 |
| behavioral and electrophysiological study of cutaneous trigeminal nerves in axolotls. i. normal innervation and reinnervation following nerve section. | behavioral responses to light tactile stimulation of the skin of the head of axolotls were variable in occurrence but were of a constant pattern. retraction of the eyes and gills followed stimulation of dorsal but not ventral skin. ventral skin yielded lowering of the head. touching near the lips caused turning of the head and a snap towards the stimulator. following section and regeneration of divisions of the trigeminal vth nerve, normal behavioral responses returned in 7-17 weeks. afferent ac ... | 1981 | 7272780 |
| mitochondrial morphology in the spermatozoa of the mexican axolotl, ambystoma mexicanum. | thin-section and freeze-fracture electron microscopy of immature and mature spermatozoa of the mexican axolotl, ambystoma mexicanum, revealed numerous small spherical mitochondria with diameters ranging from 0.15 to 0.22 micrometers. both the spherical form and the small size of these mitochondria were confirmed by serial thin-section studies. in mature spermatozoa, the mitochondria are located in the midpiece region, in tight contact with each other, exhibiting an almost crystalline arrangement ... | 1981 | 7320076 |
| amphibian pronephric duct morphogenesis: segregation, cell rearrangement and directed migration of the ambystoma duct rudiment. | the axolotl pronephric duct rudiment is readily accessible to both sem observation and surgical manipulation. the rudiment segregates from the dorsal part of the lateral mesoderm and then extends caudally along the ventrolateral border of the segmenting comites, eventually contacting the cloacal wall. the marked thinning of the rudiment which accompanies this migration is paralleled by a corresponding reduction in cell number across the duct's diameter and by caudad translocation and elongation ... | 1981 | 7310283 |
| [effects of concanavalin a on neural induction in the young gastrula of the axolotl (ambystoma mexicanum shaw. ) and pleurodele (pleurodeles waltlii michah.)]. | presumptive ectoderm from young gastrulae of the pleurodele and the axolotl was treated with concanavalin a(5-25 micrograms/ml). then, it was combined, in a sandwich, with the dorsal lip of the blastopore and cultured in vitro for 5-7 days. the results of the experiments show that the treated ectoderm becomes more fragile than untreated control ectoderm. nevertheless, the neural induction and the histological differentiation of the neural tissue appeared in a rather normal fashion. | 1981 | 7257883 |
| regeneration of subnormally innervated axolotl arms. | forearms of juvenile axolotls contain about 5000 axons, of which only 25% are myelinated and visible by light microscopy. virtually all the axons degenerate after transection of the brachial plexus, but repeated operations fail to keep the arm completely denervated. regrown nerve fibres were detected by electron microscopy after 6 weeks of attempted denervation and related to the quantity usually considered necessary for limb regeneration. such arms regenerated quite normally, provided their inn ... | 1981 | 7276803 |
| vitellogenin synthesis and characterisation of the liver estrogen receptor in the neotenous salamander ambystoma mexicanum. | | 1981 | 7227646 |
| two actin variants in developing axolotl heart. | | 1981 | 6894432 |
| [autoradiographic investigations on postnatal proliferative activity of the telencephalic and diencephalic matrix-zones in the axolotl (ambystoma mexicanum), with special references to the olfactory organ (author's transl)]. | the localization and proliferative activity of the matrix-zones has been investigated in the telencephalon and in the diencephalon of 21 axolotls (ambystoma mexicanum) by means of autoradiographs, after injection of tritiated thymidine at different stages of the postnatal life. there are no previous detailed autoradiographical reports on postnatal brain development in the axolotl. matrix-zones (i.e. ventricular and subventricular zone) exist in the dorsal part and in the ventral part of the tele ... | 1981 | 7336815 |
| antigen trapping in ambystoma mexicanum. role of secondary lymphoid organs. | | 1981 | 7238968 |
| comparative immunocytochemical localization of prolactin and somatotropin in the pituitaries of lepidosiren paradoxa, rana temporaria and ambystoma mexicanum. | the cellular binding sites of anti-oprl igg and anti-bsth igg were demonstrated in the pituitary glands of lepidosiren paradoxa, rana temporaria and ambystoma mexicanum by means of the unlabeled antibody enzyme method by light and electron microscopy (the latter only in lepidosiren). with the light microscope prl or prl-like substances and sth or sth-like substances were revealed in two different cell types in the distal lobe corresponding to the acidophils. however, as a result of the insuffici ... | 1981 | 7018691 |
| lactate dehydrogenase isoenzyme pattern as a marker of lymphocyte populations in the axolotl (ambystoma mexicanum). | | 1981 | 6976277 |
| pattern regulation and the origin of extra parts following axial misalignments in the urodele limb bud. | pattern regulation following axial misalignments in the stage-38+to stage-40 urodele limb bud was studied on one newt and two salamander species. grafts of the distal tip of the limb bud were made to the stump of a host limb bud from which a similar piece had been removed. the grafts were positioned with either their anteroposterior, dorsoventral, or both of these axes reversed with respect to the host axes. mirror-imaged duplications, positioned posteriorly or both anteriorly and posteriorly, o ... | 1980 | 7310274 |
| evidence that the premature death mutation (p) in the mexican axolotl (ambystoma mexicanum) is not an autonomous cell lethal. | cell-lethal developmental mutations, which are presumed to affect the viability of all cells in a mutant embryo, have been distinguished from other development lethals on the basis of the results of parabiosis and transplant experiments. premature death (p), previously classified as a cell lethal, does not survive parabiosis. however, transplants involving mutant eye, flank epidermis and primordial limb tissue all survived on a normal recipient. the mutant, therefore, cannot be considered a true ... | 1980 | 7310271 |
| regions of the brain influencing the projection of developing optic tracts in the salamander. | eye primordia from the mexican axolotl or the california newt were transplanted into hosts of either species. these "third" eyes often developed an optic nerve that penetrated the host brain and made one of three central projections: bilateral to the dorsal thalami, tecta, and basal optic nuclei; ipsilateral to the same areas; or ipsilateral into the cord. the type of projection made by a transplanted eye seemed to depend on where its nerve first entered the brain. the optic fibers that reached ... | 1980 | 7440804 |
| the effects of eliminating impulse activity on the development of the retinotectal projection in salamanders. | the california newt taricha torosa manufactures tetrodotoxin, a blocker of voltage-sensitive sodium channels and therefore of action potentials.the newt's own nervous system is insensitive to this toxin. grafting an embryonic eye to the newt from a tetrodotoxin-sensitive species, the mexican axolotl, blocks action potentials in the retinal ganglion cells of the transplanted eye. neuroanatomical and electrophysical techniques demonstrate that while such ganglion cells are incapable of firing impu ... | 1980 | 7440803 |
| 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 |
| segmental innervation of rotated and supernumerary axolotl hindlimbs. | the segmental nerve supply to axolotl limbs was misrouted by severing the limbs at the level of the femur, rotating them 180 degrees around their long axis, and then suturing them to the intact proximal stump. following return of the blood supply to the rotated limb by the cross-anastomosing of blood vessels, a blastema often formed to the side of the rotation site giving rise to a supernumerary limb. the muscles of both rotated and supernumerary limbs were innervated by the segmental nerves. th ... | 1980 | 7462973 |
| intercalary regeneration of symmetrical thighs in the axolotl, ambystoma mexicanum. | | 1980 | 7000578 |
| 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 |
| morphogenetic properties of the skin in axolotl limb regeneration. | a study has been made of the morphogenetic properties of anterior and posterior skin from the lower forelimb of the axolotl. the basic experiment consisted of a graft of a half cuff of skin from a donor to a host limb followed by a 2-week healing period, amputation through the graft, and a study of the resulting regenerate. limbs with double posterior skin formed double posterior regenerates and, in contrast, limbs with double anterior skin formed normal or slightly hypomorphic regenerates. post ... | 1980 | 7003051 |
| inducing effects of the grey crescent region of early developmental stages of ambystoma mexicanum. | parts of the grey crescent region of 1-2 cell, 8 cell and morula stages ofambystoma mexicanum were combined with presumptive gastrula ectoderm of the same species (sandwich method).grey crescent material of the early cleavage stages induced neural tissues at a very low rate (6%-7%).from the morula stage onwards, the inducing ability of the grey crescent area increased and led to the formation of mesodermal as well as neural organs. the implanted area did not participate in the organ formations. | 1980 | 28304975 |
| regulation and potency in the forelimb rudiment of the axolotl embryo. | anterior, posterior, dorsal and ventral halves of the pre-bud forelimb rudiment of tail-bud axolotl embryos can all give rise to normal limbs after the complementary half has been removed. a histological study of the regulation of the posterior half rudiment showed no requirement for mesodermal healing across the gap, and no proliferative zone. the development of the limb bud on the operated side lags behind that of the control bud for several weeks of larval life. when half limb rudiments and d ... | 1980 | 7430930 |
| experiments on developing limb buds of the axolotl ambystoma mexicanum. | various experiments were performed on the limb buds of axolotls to compare the behaviour of amphibian limbs with that previously reported for chick limbs. following removal of the tip or whole limb bud, extensive powers of regulation were observed since complete limbs always formed. similarly after distal to proximal grafts intercalary regulation occurred to produce perfect limbs and after proximal to distal grafts serial repetitions resulted. transplantation and rotation of limb buds to reverse ... | 1980 | 7430928 |
| gap junctions in early amphibian embryos. | cell pairs from late cleavage and early blastula ambystoma mexicanum embryos were found to be electrotonically coupled. thin-section electron microscopy revealed typical gap junctions between the cells. freeze-fracture electron microscopy showed the gap junctions to be comprised of aggregations of 8.5-nm p-face particles and corresponding e-face pits. the conductance of the amphibian embryonic gap junction is known to be voltage-dependent, but no obvious gating structure was resolved by these mo ... | 1980 | 7416050 |
| ultrastructure of the renal juxtaglomerular complex and peripolar cells in the axolotl (ambystoma mexicanum) and toad (bufo marinus). | renal juxtaglomerular regions were examined in the axolotl (ambystoma mexicanum and toad (bufo marinus). prominent granulated peripolar epithelial cells were found surrounding the origin of the glomerular tuft in the axolotl. these cells resembled the peripolar cells recently discovered in mammalian species. they contained multiple electron-dense cytoplasmic granules, some of which showed a paracrystalline substructure and signs of exocytoxic activity. such cells were difficult to find and small ... | 1980 | 7410189 |
| regeneration of reversed aneurogenic arms of the axolotl. | aneurogenic arms of young axolotls were implanted into the flank as heterotopic autografts with reversed proximo-distal orientation. the formerly proximal ends of such arms regressed to a variable extent, and then either regenerated or could do so following a second amputation. the regenerate always contained a complete sequence of skeletal elements between the adjacent stump skeleton and terminal digits, being a mirror image of the implanted arms with identical transverse axes but an opposed pr ... | 1980 | 7400749 |
| spatial distribution of abundant proteins in oocytes and fertilized eggs of the mexican axolotl (ambystoma mexicanum). | | 1980 | 7372013 |
| neural crest cell migration in relation to extracellular matrix organization in the embryonic axolotl trunk. | | 1980 | 7371990 |
| electrical activity in cardiac mutant axolotl hearts. | electrical recordings from the hearts of both cardiac lethal mutant and normal embryos showed the presence of action potentials conducted over the heart tube. ionic coupling and gap junctions also were observed in both. these results suggest that the absence of heart function in mutant embryos does not result from a defect in electrical activity. | 1980 | 7373269 |
| distal transformation from double-half forearms in the axolotl, ambystoma mexicanum. | | 1980 | 7371978 |
| regeneration of symmetrical forelimbs in the axolotl, ambystoma mexicanum. | | 1980 | 7371977 |
| melanogenesis in oocytes of wild-type and mutant albino axolotls. | | 1980 | 7371975 |
| hemoglobins of an amphibia, the neotenous ambystoma mexicanum. complete amino-acid sequence of the alpha chain of the major component using automatic solid-phase edman degradation. | the primary structure of axolotl (neotenous ambystoma mexicanum) alpha chain has been determined. nh2-terminal sequence data were performed using the solid-phase method. complete amino acid assignments were deduced from the sequences of peptides obtained after cleavage with cyanogen bromide; the methionine-containing peptides, isolated from alpha chain tryptic digest, allowing the alignment of these fragments. all overlaps have been clearly established. axolotl alpha chain contains 142 residues, ... | 1980 | 7358052 |
| immunofluorescence studies for myosin, alpha-actinin and tropomyosin in developing hearts of normal and cardiac lethal mutant mexican axolotls, ambystoma mexicanum. | recessive mutant gene c in axolotl embryos results in an absence of normal heart function. immunofluorescence studies were done to determine the distributions of myosin, tropomyosin and alpha-actinin in the hearts of normal and mutant siblings. anti-myosin specifically stains the a bands of myofibrils in normal hearts and reveals a progressive increase in myofibril organization with development. mutant hearts display less staining for myosin than normal and localization is mainly in amorphous co ... | 1980 | 6989943 |
| neural crest replaced by gastrula ectoderm in amphibia. effect on neurulation, cns, gills and limbs. | early axolotl gastrula ectoderm was grafted into early triturus neural stages in place of excised neural folds at the gill and anterior trunk level. macroscopically the young graft behaves like normal neural fold material: it follows the closing host neural plate to the dorsal midline, folds into the host's interior and, especially in the gill region, moves ventrad beneath the host's epidermis. these movements cannot be interpreted as active migration. they are the result of passive displacement ... | 1980 | 7457916 |
| evidence of the first genetic activity required in axolotl development. | | 1980 | 7444204 |
| 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 |
| 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 |
| 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 |
| positional information in the forelimb of the axolotl: experiments with double-half tissues. | | 1979 | 527764 |
| steroidogenesis in axolotl testis. histochemistry of two major enzymes related to cell type, spermatogenesis, and substrate. | | 1979 | 499762 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| maintenance of growth- and thyroid-stimulating properties of ectopic pituitaries in the mexican axolotl (ambystoma mexicanum). | | 1979 | 467973 |
| chloride-dependent sodium transport in the skin of ambystoma mexicanum [proceedings]. | | 1979 | 458718 |
| axon reflexes in axolotl limbs: evidence that branched motor axons reinnervate muscles selectively. | | 1979 | 428494 |
| 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 |
| development of synaptic connections between different segmental motoneurones striated muscles in an axolotl limb. | | 1979 | 446887 |
| [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 |
| 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 |
| 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 |
| morphogenetic interactions occurring between blastemas and stumps after exchanging blastemas between normal and double-half forelimbs in the axolotl, ambystoma mexicanum. | | 1979 | 437319 |
| 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 |
| 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 |
| 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 |
| 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 |
| regulation of the mauthner cell following unilateral rotation of the prospective hindbrain in axolotl (ambystoma mexicanum) neurulae. | | 1978 | 679039 |
| the effect of healing time on the proximodistal organization of double-half forelimb regenerates in the axolotl, ambystoma mexicanum. | | 1978 | 751844 |
| studies on the effects of bleaching amphibian rod pigments. iv. photoresponses recorded intracellularly from axolotl red rods following bleaching flashes. | | 1978 | 668824 |
| studies on the effects of bleaching amphibian rod pigments in situ. iii. linear dichroism in axolotl red rods before and during bleaching. | | 1978 | 668823 |
| 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 |
| 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 |
| supernumerary limbs in the axolotl. | | 1978 | 643082 |
| interaction between foreign and regenerating axons in axolotl muscle. | | 1978 | 647386 |
| 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 |
| 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 |
| 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 |
| 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 |
| experimental studies on a mutant gene, a, causing albinism in the axolotl, ambystoma mexicanum. | | 1978 | 414944 |
| 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 |
| [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 |
| experimental studies on two mutant genes, r and x, in the mexican axolotl (ambystoma mexicanum). | | 1978 | 620874 |
| the occurrence of supernumerary limbs following blastemal transplantation in the regenerating forelimb of the axolotl, ambystoma mexicanum. | | 1978 | 620870 |
| myogenesis and inductive processes during heart development in mexican axolotls (ambystoma mexicanum). | | 1978 | 367464 |
| 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 |
| 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 |
| 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 |
| neuroanatomy of spastic, a behavior mutant of the mexican axoloti: purkinje cell distribution in the adult cerebellum. | the spastic mutant, found in the mexican axolotl, shows swimming coordination and equilibrium deficiencies. histological analyses of wild-type and spastic mutant cerebella previously characterized in physiological studies revealed changes in purkinje cell location in the mutant auricle or vestibulo-cerebellum. purkinje cells are "translocated" ventrally correlated with a similar translocation of vestibular single units described previuosly (ide, '77). where wild-type purkinje cells are distribut ... | 1977 | 915044 |
| neurophysiology of spastic, a behavior mutant of the mexican axoloti: altered vestibular projection to cerebellar auricle and area acoustico-lateralis. | the spastic mutant of ambystoma mexicanum shows deficiencies in swimming coordination and equilibrium. behavior "phenocopy" experiments done previously indicated that vestibular projections to cerebellum and hindbrain interneurons might be responsible for mutant behavior patterns. to test function in mutant vestibular projections, single unit recordings were carried out in the vestibulo-cerebellum (auricle) and hindbrain area acoustico-lateralis (aay) of wild-type and mutant animals in response ... | 1977 | 915043 |
| axolotl stretch reflex [proceedings]. | | 1977 | 599458 |
| genetic and experimental studies on three associated mutant genes in the mexican axolotl: st (for stasis), mi (for microphthalmic) and h (for hand lethal). | three mutant genes, st, mi, and h, were discovered in an axolotl male received from mexico city. all three are recessive to their normal alleles, and appear to segregate independently. larvae homozygous for st (for stasis) suffer blockage of the circulation at hatching or shortly after, and the majority soon die; any surviving live only a few weeks at most. the mi/mi (microphthalmic) can be identified at the feeding stage. none survives more than a few days. the h/h (hand lethals) live until the ... | 1977 | 925667 |
| 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 |
| 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 |
| preferential expression of the maternal allele for alcohol dehydrogenase (adh) in the amphibian hybrid ambystoma mexicanum (axolotl) x ambystoma texanum. | | 1977 | 561728 |
| 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 |
| cardiac mutant salamanders: evidence for heart induction. | homozygosity for gene c in ambystoma mexicanum results in no detectable heartbeat in situ. alteration of the cardiac environment through organ culture results in rapid initiation of spontaneous heartbeat, indicating that absence of cardiac function in situ is not the result of failure of embryonic induction. | 1977 | 908918 |
| a scanning electron microscopic comparison of the development of embryonic and regenerating limbs in the axolotl. | a comparison between the surface features of embryonic limb development and limb regeneration was made in the axolotl. scanning electron microscopy revealed an overall similarity between embryonic and regenerating limbs. a notable feature was the lack of a morphologically discrete apical epidermal specialization on the surface of any of the limbs. histological preparations revealed no thickening of the apical epidermis in embryonic limbs. there is a definite thickening of the apical epidermis in ... | 1977 | 908913 |
| thyroxine-induced gill resorption in the axolotl (ambystoma mexicanum). | | 1977 | 903970 |
| dosage effects of the white (d) and melanoid (m) genes on pigment pattern in the mexican axolotl, ambystoma mexicanum, shaw. | | 1977 | 892230 |
| spontaneous release of transmitter from 'repressed' nerve terminals in axolotl muscle. | | 1977 | 18677 |