Publications

lh-rh neuron system of the newt by immunohistochemical study.	the location of lh-rh producing neurons, the pathways and terminal distributions of their fibers in the newt, cynops pyrrhogaster were studied immunohistochemically. the lh-rh positive perikarya are located in the nucleus of the diagonal band of broca and the medial septal nucleus. no lh-rh immunoreactive neuronal perikarya could be detected in the diencephalon. the pathways of fibers originating from the lh-rh reactive neurons were classified into three groups: the first project to the median e ...	1979	395922
occurrence of sym-homospermidine in the japanese newt, cynops pyrrhogaster pyrrhogaster.		1979	428556
spontaneous regressive epitheliomas in the japanese newt, cynops pyrrhogaster.	spontaneous tumors in urodele amphibians have been considered uncommon, and this resistance has sometimes been associated with the natural regenerative capacity of tissues in such species. this report describes spontaneous, nonpigmented, benign epitheliomas which were found in 44 of 1586 (2.8%) adult newts, cynops pyrrhogaster, captured in central japan. both sexes were affected equally, usually with single tumors occurring at any epidermal site. under laboratory conditions, these large tumors r ...	1979	445390
role of sodium ions in p-aminohippurate transport by newt kidney.	1. the effect of external na+ concentration on p-aminohippurate uptake by isolated kidneys of newt (triturus pyrrhogaster) was studied kinetically and electrophysiologically. 2. p-aminohippurate uptake conformed to michaelis-menten type kinetics in regard to both p-aminohippurate and na+ concentrations in the incubation medium. kinetic studies revealed that reduction of na+ concentration increased the values of kt without altering the maximal rate (v) of p-aminohippurate uptake. the values of kt ...	1979	454592
effects of changes in sodium electrochemical potential gradient on p-aminohippurate transport in newt kidney.	1. the relation between p-aminohippurate uptake and the electrochemical potential gradient of na+ (delta muna+) across the peritubular membrane was examined in newt (triturus pyrrhogaster) kidney. the delta muna+ was modified by changing cellular na+ concentration and/or lowering the electrical potential difference across the peritubular membrane (peritubular membrane potential) 2. elevation of external k+ concentration or addition of alanine at 40 mm to the medium decreased the delta muna+ main ...	2004	534632
mechanism of cleavage of newt eggs.	cytokinesis by contraction of the base of the cleavage furrow and the dependence of the position of the future furrow on the arrangement of cytoplasm under it have been demonstrated at relatively earlier stages of cleavage in amphibian eggs. the following experiments and observations on dividing eggs of the newt cynops pyrrhogaster indicated the presence of the contracting force at the base of the furrow and revealed that the above cleavage mechanisms occurred throughout cleavage. (1) deformatio ...	1979	573273
cyclic changes in the cortical layer of non-nucleated fragments of the newt's egg.	various changes in the cortical layer of the amphibian egg have been observed during cleavage; for example, rounding up in the animal hemisphere, increase in stiffness of the surface and reactivity of the cortex to furrow-inducing cytoplasmic components. the three kinds of change occur synchronously with the cleavage cycle. the present experiments were aimed at determining whether the above changes in the cortical layer are caused exclusively by the nucleus or autonomously by the cytoplasm. uncl ...	1979	573307
on the vascular architecture of the carotid labyrinth in cynops pyrrhogaster and onychoactylus japonicus.	the fine vascular arrangement of the carotid labyrinth in two species of urodeles, cynops pyrrhogaster and onychodactylus japonicus was investigated. india ink-gelatin injected preparations were examined under the dissecting microscope. resin casts of the blood vessels prepared using the method of murakami (1971) were observed in the scanning electron microscope. in both species, the common carotid artery terminated in the central chamber from which arose two retia mirabilia, i.e. an external ca ...	1977	597008
[phylogenetic studies on some japanese amphibia by means of immunoelectrophoresis. ii. relationships of some amphibians to japanese pond frogs (author's transl)].	since the japanese pond frogs (rana nigromaculata and r. brevipoda) are known to be very closely allied with each other in morphological, ecological, physiological or immunological characters, the phylogenetical relationships between the japanese pond frogs and other 10 species of japanese amphibians were investigated by means of immunoelectrophoretic analysis of liver extract. the results obtained are as follows: (1) there are conservative antigens which are commonly found in all species of anu ...	1978	631194
effect of starvation & hypophysectomy on amino acid levels of ovaries of triturus pyrrhogaster laur.		1978	700806
[phylogenetic studies on some japanese amphibia by mean of immunoelectrophoresis. i. relationships of some frogs and newt to toad (author's transl)].	the phylogenetic relationship among toad, frogs and newt from japan was investigated by means of immunoelectrophoresis. homologous, heterologous and non-identity reactions between rabbit anti-bufo bufo antiserum and antigen from each of 13 species and 2 subspecies of japanese amphibia were examined. the number and positions of arcs appeared in these reactions were compared. the relationship observed in the comparison well coincided with the classification of the upper taxa of amphibia; viz 1) hy ...	1975	808417
axon regeneration across the site of injury in the optic nerve of the newt triturus pyrrhogaster.	the process by which axons regenerate following a freeze injury to the optic nerve of the newt was analyzed by light and electron microscopy. freezing destroys cellular constituents in a one millimeter segment of the nerve, leaving intact the basal lamina and the blood supply to the eye. no axons are seen at the site of injury one to seven days post lesion. this contrasts with the persistence of normal-appearing but severed unmyelinated axons within the cranial stump which thus give a false appe ...	1977	862013
the relationship of a specific chromosomal region to the development of the acrosome.	in early spermatids of urodeles the chromosome segments bearing constitutive heterochromatin are localized in one half of the round nucleus; this region becomes the basal part of the long nucleus of the spermatozoon. the euchromatic chromosome segments extend toward the anterior nuclear pole in a bouquet configuration (macgregor and walker, 1973). in the course of spermiohistogenesis, one of the heterochromatic regions (the acrosomal chromocenter) migrates from the basal part to the anterior hal ...	1976	949922
cytological and microspectrophotometric analysis of mesodermalized explants of triturus gastrula ectoderm.	using isolated presumptive ectoderm of the newt (triturus pyrrhogaster) embryos as a reactor and extract of rat bone marrow as a mesodermal inductor, changes of cell number and mitotic index of the reactor cells were studied. in early stages of cultivation the increase in cell number in the mesodermalized ectodermal piece was slower than in the non-mesodermalized epidermal piece; but after 24 h it showed abrupt increase and reached a cell population equal to that of the control at 48 h of cultiv ...	1976	978130
movement of the cell surface and change in surface area during cleavage in the newt's egg.	in cleaving eggs of the newt, cynops pyrrhogaster, the behaviour of the egg surface was analysed by observing linear and area changes in a transplanted piece of cortex which differed in pigmentation from the background. results from the animal hemisphere showed that the surface in the cleavage plane shrank extensively in the region where the early cleavage furrow was being formed. on both sides of the cleavage plane, the surface began to shrink in a direction parallel to the cleavage furrow and ...	1976	987048
electron microscopic stldy of the developing lateral-line organ in the embryo of the newt, triturus pyrrhogaster.	the morphological sequence of events occurring in the development of the lateral-line organ was investigated in the embryo of the newt, triturus pyrrhogaster, by means of electron microscopy. six stages of development have been defined for convenience of description. the primordium of the lateral-line organ migrating from the pre- and post-auditory placodes is segmented into a small cell mass accompanied by a few schwann cells enveloping nerve fibers. in the clump of cells of the lateral-line pr ...	1976	1008255
architecture of the marrow vasculature in three amphibian species and its significance in hematopoietic development.	architecture of the bone marrow vasculature, particularly that of the femur, was analyzed in three amphibian species in relation to the early phylogeny of marrow hematopoiesis. a dye-injection method and histological techniques, including both serial sectioning and reconstruction methods, were used for this purpose. from these observations the following conclusions may be drawn. (1) marrow hematopoiesis is absent from the femur of the urodelan (triturus pyrrhogaster) and appears first in the fem ...	1976	1083670
studies on the gastrulation of amphibian embryos: light and electron microscopic observation of a urodele cynops pyrrhogaster.	the course of gastrulation in embryos of a urodele, cynops pyrrhogaster, was studied with 1 mum epon sections and transmission and scanning electron microscopy. during the initial period of gastrulation, the bottle cells and a groove are formed in the dorsal part. the outer ends of the bottle cells have many microvilli, an electron-dense layer and many small vesicles. microtubules are present parallel to the long axis of the bottle cells, and a yolk-platelet-free region is observed at the inner ...	1975	1214113
an immunohistochemical study of regenerating newt retinas.	light-microscopical examination was carried out to investigate the emergence and development of several classes of immunoreactive cells in regenerating retinas of the adult newt (triturus pyrrhogaster) after total retinal ablation. immunoreactive proliferating cell nuclear antigen (ir-pcna, a marker for replicating cells) was present in nuclei of all neuroblasts in the early mono-layered to several-layered stages (15-20 days after retinal ablation; days 15-20), but was lost progressively in an i ...	1992	1356660
[immunocytochemical studies on the pancreatic endocrine cells in the japanese newt (cynopus pyrrhogaster)].	pancreatic endocrine cells were examined by light and electron microscopic immunocytochemistry to discuss the co-localization of peptides in one cell type. a cells were irregular in shape with an occasional long cytoplasmic process, and contained glucagon-immunoreactive granules with various contours. these granules were 160-300nm in diameter with various density, and also immunoreactive to anti-human pancreatic polypeptide (pp) serum. a part of them were further immunoreactive to anti-somatosta ...	1992	1360408
epibolic extension of the presumptive ectodermal layer of embryos of the newt cynops pyrrhogaster before and during gastrulation.	epibolic extension of the presumptive ectodermal layer (pel) was investigated in embryos of the newt cynops pyrrhogaster before and during gastrulation. the pel was composed of only one layer of columnar cells at all stages examined. the cells of the pel became elongated from the blastula to the early gastrula stage. they were most elongated at the early gastrula stage and then shortened during gastrulation. present observations suggest that changes in cell shape of the pel play an important rol ...	1992	1402739
the origin of the luteinizing hormone-releasing hormone (lhrh) neurons in newts (cynops pyrrhogaster): the effect of olfactory placode ablation.	neurons containing luteinizing hormone-releasing hormone (lhrh) are first detected in newt embryos (cynops pyrrhogaster) in the olfactory epithelium and ventromedial portion of the olfactory nerve, after which they sequentially appear in the intracerebral course of the terminal nerve at prometamorphosis, and in the septo-preoptic area at postmetamorphosis. in adults, however, lhrh-immunoreactive cells are rarely seen in the nasal region, and their distribution shifts into the brain, suggesting t ...	1965	1423481
presence of d-aspartate oxidase and free d-aspartate in amphibian (xenopus laevis, cynops pyrrhogaster) tissues.	1. this paper is the first report on the presence of d-aspartate oxidase activity and free d-aspartate in the amphibian tissues. 2. the presence of d-aspartate oxidase activity in tissues of clawed toad (xenopus laevis) and japanese newt (cynops pyrrhogaster) was demonstrated by requirements for enzyme activity, selective inhibition with meso-tartrate and substrate specificity. 3. in each animal, the highest activity was found in kidney, followed by liver and brain, and no gender difference in t ...	1992	1424565
comparative study of sexual dimorphism of the innominate bone in rodents and amphibians.	sexual dimorphism in the shape of the innominate bone was demonstrated in the rat, mouse, chinese hamster (cricetulus griseus), frog (ranna nigromaculata), and newt (cynops pyrrhogaster) with a computer-assisted morphometric technique. in the rat, mouse, and hamster, ratios of ischium and pubis widths to the innominate bone length (inl) were larger in the males than in the females; however, the ratio of pubis length to inl was larger in the females than in the males. in the frog, the ratio of di ...	1992	1443668
expression and distribution of regeneration-responsive molecule during normal development of the newt, cynops pyrrhogaster.	we have investigated the expression and distribution of the regeneration-responsive molecule, 2ni-36, the loss of which is responsible for initiation of dedifferentiation of dorsal marginal iris pigmented epithelial cells to regenerate a lens. in the process of the normal development of the newt, the expression of 2ni-36 could not be detected in embryos at the early developmental stages, i.e., cleavages, gastrulation and neurulation, nor through later developmental stages to tail-bud, even thoug ...	1992	1445784
reduction of papilloma size by ultraviolet irradiation in the japanese newt, cynops pyrrhogaster.	experiments were conducted on 44 captive japanese newts (cynops pyrrhogaster) to test the hypothesis that ultraviolet (uv) irradiation might inhibit growth or induce regression of spontaneous skin papillomas of probable viral origin. an empirically derived exposure to uv irradiation (42 microw per cm2 per day) induced reduction of papilloma size which began approximately 4 weeks after irradiation was initiated. this regression included histological evidence of tissue vacuolization and cellular n ...	1992	1556253
appearance and maturation of voltage-dependent conductances in solitary spiking cells during retinal regeneration in the adult newt.	electrical membrane properties of solitary spiking cells during newt (cynops pyrrhogaster) retinal regeneration were studied with whole-cell patch-clamp methods in comparison with those in the normal retina. the membrane currents of normal spiking cells consisted of 5 components: inward na+ and ca++ currents and 3 outward k+ currents of tetraethylammonium (tea)-sensitive, 4-aminopyridine (4-ap)-sensitive, and ca(++)-activated varieties. the resting potential was about -40 mv. the activation volt ...	1992	1625217
characterization of a tandemly repeated dna sequence family originally derived by retroposition of trna(glu) in the newt.	a previous report from this laboratory showed that in vitro transcription of total genomic dna of the newt cynopus pyrrhogaster resulted in a discrete sized 8 s rna, which represented highly repetitive and transcribable sequences with a glutamic acid trna-like structure in the newt genome. we isolated four independent clones from a newt genomic library and determined the complete sequences of three 2000 to 2400 base-pair psti fragments spanning the 8 s rna gene. the glutamic acid trna-related se ...	1991	1660072
liver ultrastructure and a new cell type in the japanese newt, cynops pyrrhogaster.	the liver of the japanese newt, cynops pyrrhogaster, has been investigated using light, scanning, and transmission electron microscopy. hepatic parenchyma was composed of clusters and cords or tubules of polyhedral cells separated by a sinusoidal net. hepatocytes had spherical, euchromatic nuclei with one or more nucleoli and stacked mitochondria with sparse cristae and dense bodies. rough endoplasmic reticula formed peribiliary stacks and diffusely scattered vesicles and tubules. smooth endopla ...	1991	1815727
homologous radioimmunoassay for bullfrog growth hormone.	antiserum against bullfrog growth hormone (fgh) was produced by immunizing rabbits with the highly purified fgh obtained from adenohypophyses of adult bullfrogs. histological studies on bullfrog adenohypophyses revealed that the cells that immunologically reacted with the antiserum against fgh corresponded to the ones positively stained with the antiserum against rat gh. the antiserum together with fgh and 125i-fgh was employed to develop a radioimmunoassay (ria) for fgh. several dilutions of pl ...	1991	1874383
amphibian prolactins: activity in the eft skin transepithelial potential bioassay.	the effects of purified prolactins isolated from frogs (fprl; rana catesbeiana) and newts (nprl; cynops pyrrhogaster) were compared with those of ovine prolactin (oprl) and thyrotropin releasing hormone (trh) in the eft (notophthalmus viridescens) skin transepithelial potential (tep) bioassay. at total doses as low as 0.4 micrograms/animal, both fprl and nprl were as effective as oprl in reducing eft skin tep. by contrast, trh at total doses as high as 400 micrograms/animal was ineffective in al ...	1991	1908395
magnetic shielding induces early developmental abnormalities in the newt, cynops pyrrhogaster.	developing larvae of the japanese newt, cynops pyrrhogaster, were subjected for 5 days to a shielded environment in which the static magnetic field was about 10,000 times weaker (5 nt) than the geomagnetic norm, which ranges between 30 and 60 microt at the earth's surface. larvae from non-cleavage to neurula stages were exposed under shielded or normal (control) conditions and then examined for evidence of developmental abnormalities either 1 day or 20 days after treatment. the magnetic shieldin ...	1991	1930306
the occurrence of melanosomes in the newt glomus cell.	combined light and electron microscopic observations of the carotid labyrinth of the newt, cynops pyrrhogaster, revealed the occurrence of glomus cells with melanosomes (mg cells), a finding so far unreported in the amphibian carotid labyrinth. these melanosomes, which derived from melanophores, were electron-dense and usually oval (250-700 nm in diameter). they occurred in groups enclosed by a limiting membrane, and the diameter of clusters was approximately 1.5 microns. these clusters were sur ...	1991	2039662
involvement of prolactin in the regulation of plasma calcium levels in the newt, cynops pyrrhogaster.	in the newt, cynops pyrrhogaster, parathyroidectomy (ptx) brought about a marked decrease in the concentration of plasma calcium. the animals recovered from the hypocalcemia by 15 days after the operation if the pituitary gland was left intact. after ptx, no significant changes in the plasma sodium concentration were observed. experiments were then conducted to obtain direct evidence that endogenous prolactin (prl) is involved in this recovery process. recovery of the calcium level after ptx was ...	1991	2055443
differentiation of the brain stem reticular formation in the triturus, triturus pyrrhogaster.	the brain stem of the triturus was observed to be initially composed exclusively of the mantle layer. a few days before hatching, a narrow marginal layer differentiated peripherally. at the time of hatching, the marginal layer was clearly visible throughout the brain stem, except for in a medial region of the optic tectum. approximately one week after hatching, a few cells migrated into the marginal layer, and almost simultaneously, a few fibers in that layer were myelinated. cells migrating int ...	1990	2216305
control of sperm nuclear behavior in physiologically polyspermic newt eggs: possible involvement of mpf.	we have studied the mechanism controlling the behavior of accessory sperm nuclei in physiologically polyspermic eggs of the newt, cynops pyrrhogaster. our approach was to identify cytoplasmic components which would prevent the usual degeneration of accessory sperm nuclei. injection of cytoplasm from unfertilized eggs, but not fertilized ones, induced multipolar cleavage in polyspermically fertilized eggs as well as centrosome separation and formation of extra bipolar spindles in accessory sperm ...	1990	2257969
purification and properties of newt prolactin.	a highly purified prolactin (prl) was obtained from pituitary glands of newts, cynops pyrrhogaster, by extraction of acetone-dried powder with acid acetone and high-performance liquid chromatography (hplc) on mono-q (anion exchange), superose-12 (gel filtration), and tsk-gel ods-120t (reverse-phase) columns with a yield of 4.5 mg per 325 mg of protein starting material. purification was monitored by sds-polyacrylamide gel electrophoresis (page) and western blotting analysis employing antiserum a ...	1990	2295424
how is the flagellar length of mature sperm determined? ii. comparison of tubulin synthesis in spermatids between newt and xenopus in vitro.	in order to elucidate mechanisms that control flagellar length of mature sperm, we studied in synchronous cell suspension cultures flagellar growth, tubulin pool, and tubulin synthesis in round spermatids of xenopus laevis and the newt cynops pyrrhogaster. the average final length of flagella in xenopus round spermatids was 35 mum, almost the same length as that in mature sperm, whereas in the newt round spermatids, the length was 210 mum, almost half that of mature sperm. kinetics of flagellar ...	1990	2298244
observations on cardiac ultrastructure of the adult japanese newt, cynops pyrrhogaster.	investigation of atrial and ventricular cardiac ultrastructure by transmission and scanning electron microscopy of the adult japanese newt, cynops pyrrhogaster, has revealed some unique cell types and features in this amphibian. typical urodelan-type thin trabeculae composed of myocytes with conventional architecture of loosely scattered myofibrils were observed. scarce granules of variable size and density were seen in atrial myocytes, and some purkinje-like fibers were observed. unique structu ...	1990	2311100
gastric leiomyomas in the japanese newt, cynops pyrrhogaster; ultrastructural observations.	nineteen of 700 outwardly healthy captive adult japanese newts, cynops pyrrhogaster, had nodular neoplasms protruding on the gastric serosal surface. these tumours were characterized as sharply circumscribed leiomyomas of the muscularis externa with occasional submucosal involvement. ultrastructural analysis of tumour myocytes revealed irregular-shaped, well-differentiated cells with cytoplasmic processes, and reduced quantities of intracellular myofibrils. they were surrounded by enlarged inter ...	1990	2312798
comparative studies on the vascular organization of carotid labyrinths of anurans and caudates.	the three-dimensional structures of the carotid labyrinth in five species of anurans representing four families (rana nigromaculata, rana catesbeiana, bufo japonicus, hyla arborea, and xenopus laevis), and three species of caudates representing three families (cynops pyrrhogaster, hynobius nebulosus, ambystoma mexicanum) were compared using vascular corrosion castings and scanning electron microscopy (sem). anuran carotid labyrinths are spherical in shape and are classified into two groups accor ...	1990	2338718
development of cell surface activity and cell surface adhesiveness in early embryos of the newt, cynops pyrrhogaster.	the development of cell surface activity and adhesiveness was examined in relation to cleavage number in early embryos of the newt, cynops pyrrhogaster. both large hyaline bleb formation and surface adhesiveness to substratum were manifested in presumptive ectodermal cells isolated from embryos after the eleventh cleavage (mid-blastula stage). scanning electron microscopy of the inner surface of the blastocoelic wall (presumptive ectodermal cell layer) revealed the formation of large blebs after ...	1990	2350730
development and application of homologous radioimmunoassay for newt prolactin.	a specific and sensitive homologous radioimmunoassay (ria) for newt (cynops pyrrhogaster) prolactin (prl) was developed. prl isolated from newt pituitary glands was used for generating antiserum in a rabbit, for radioiodination, and for the standard. several dilutions of plasma and pituitary homogenate of newts yielded dose-response curves which were parallel to the standard curve. plasma from hypophysectomized newts showed the least amount of cross-reaction. pituitary homogenates of other speci ...	1990	2354781
cleavage plane determination in amphibian eggs.	in the present study using eggs of cynops pyrrhogaster and xenopus laevis, we examined (1) structural changes in the cytoplasm before the appearance of the cleavage furrow using a cytochemical method, (2) the time of cleavage plane determination depending on the mitotic apparatus (ma), by changing the shape of the eggs, and (3) the time of arrival of the "cleavage stimulus" at the cortex, by injecting colchicine solution or removing cytoplasm. results were as follows: (1) in amphibian eggs the d ...	1990	2356982
transient outward currents and changes of their gating properties after cell activation in thrombocytes of the newt.	1. the electrical properties of the cell membrane of thrombocytes in the newt, triturus pyrrhogaster, were studied using the whole-cell variation of the patch-electrode voltage-clamp technique. 2. in medium containing ca2+ (1.8 mm), activated thrombocytes became round and then spread on the glass. activation of thrombocytes was inhibited by the removal of external ca2+ and addition of 1 w/v% albumin to the external media. 3. for thrombocytes kept in the resting state, depolarizations more positi ...	2008	2443665
electrophysiological properties of three types of granulocytes in circulating blood of the newt.	1. the electrophysiological properties of three subtypes of granulocytes obtained from the circulating blood of the newt, triturus pyrrhogaster, were studied using the whole-cell variation of the patch-electrode voltage-clamp technique. 2. neutrophils were identified by their multilobulated nucleus in the cytoplasm. basophils and eosinophils, having characteristic granular structures in their cells, could definitely be distinguished from other leucocytes. the reliability of cellular identificati ...	1989	2484207
amphibian (urodele) myotomes display transitory anterior/posterior and medial/lateral differentiation patterns.	myotome differentiation during mexican axolotl (ambystoma mexicanum) somitogenesis was analyzed by employing anti-actin and anti-myosin monoclonal antibodies as molecular probes. myotome differentiation occurs after segmentation and proceeds in the cranial-to-caudal direction along the somite file. within individual somites myotome differentiation displays distinct polarities. examination of the somite file at the tailbud stage revealed that soon after segmentation, actin/myosin accumulate predo ...	1989	2647546
effects of salts in promoting the adhesion of amphibian gastrula cells.	presumptive ectodermal and endodermal cells were isolated from the gastrula of the newt cynops pyrrhogaster, and the effects of salts on embryonic cell adhesion were examined. when the concentrations of nacl, kcl, mgso4 and ca (no3)2 in the culture medium were increased individually, they all effectively promoted ectodermal cell adhesion. mgso4 and ca(no3)2 promoted endodermal cell adhesion, but nacl and kcl did not. the culture medium containing increased nacl (90 mm) nonspecifically promoted e ...	1989	2723609
an electrically mediated block to polyspermy in the primitive urodele hynobius nebulosus and phylogenetic comparison with other amphibians.	at fertilization, the egg of the primitive urodele, hynobius nebulosus, produced a fertilization potential which rose from -12 to +47 mv. a similar activation potential was elicited by pricking with a needle, by applying a23187, or by electric shock. the potential change was mediated by an increased permeability to cl-. clamping the egg's membrane potential at +40 mv blocked fertilization, while clamping at +20 mv induced polyspermy. these results indicated the occurrence of an electrical polysp ...	2009	2744241
evidence that the voltage-dependent component in the fertilization process is contributed by the sperm.	to investigate the mechanisms that account for the voltage dependence of fertilization and provide an electrical block to polyspermy, we studied cross-fertilizations between three species of amphibians having different degrees of voltage dependence. anurans, such as the toad bufo japonicus, as well as the primitive urodele hynobius nebulosus, have voltage-dependent fertilization; other urodeles, such as cynops pyrrhogaster, have voltage-independent fertilization (y. iwao, 1989, dev. biol. 134, 4 ...	2009	2744242
development of the heartbeat during normal ontogeny and during long-term organ culture of hearts of the newt, cynops pyrrhogaster.	development of cardiac contraction was investigated in the newt, cynops pyrrhogaster, during normal development and in hearts maintained in long-term organ culture. in the embryos the heart began beating as early as stage 33. the heart rate increased up to stage 52 and then gradually decreased to the adult rate by stage 60. the heart rate showed a logarithmic temperature dependence. in organ-cultured hearts the pattern of heart rate depended on the stage at which the heart was explanted; culture ...	1989	2766048
developmental physiology of cardiac contraction in the japanese newt in vivo and in vitro.	development and differentiation of whole hearts of larvae of an experimental amphibian species, the japanese newt (cynops pyrrhogaster), were studied in vitro and in vivo with particular reference to cardiac contraction, its temperature sensitivity and morphology. hearts cultured in the solid or flat state in plastic flasks for 27 days developed from stage 35 to stage 55 and corresponded closely to in vivo developing hearts with respect to morphologic criteria and temperature sensitivity of card ...	1989	2795664
ultrastructural characterization of the spontaneous papilloma of japanese newts.	the spontaneous epithelioma of the japanese newt, cynops pyrrhogaster, is a useful animal model for study of development and regression of papillomata of suspected viral origin. therefore, ultrastructural studies of this cutaneous tumor were undertaken in order to characterize this model further. the ultrastructure of normal cynops pyrrhogaster epidermis resembled teleost more than anuran epidermis. surface cells of the bilayered stratum corneum were covered by micro-ridges and contained promine ...	1989	2804952
na/k pump activity in the new membrane formed at first cleavage in cynops pyrrhogaster eggs.	resting membrane potentials (em) increased in the negative direction during first cleavage in cynops pyrrhogaster eggs whose new membranes formed at first cleavage were exposed to bathing solutions by removing the vitelline envelopes. em was -11.4 and -87.2 mv at the one- and two-cell stages, respectively. na/k pump activity contributed to em at the two-cell stage by about -30 mv. the distribution of na/k atpase activity was cytochemically studied by ernst's method (s. a. ernst, 1972, j. histoch ...	1988	2832229
teratogenic effects of carcinogenic agents on limb regeneration in the japanese newt cynops pyrrhogaster.	normal regeneration of the amputated forelimb of the japanese newt cynops pyrrhogaster and regeneration after a single intraperitoneal injection of three potent mutagenic/carcinogenic agents was investigated. three dose levels of each agent and controls were tested for teratogenicity in this newt model with the following chemicals: n-methyl-n'-nitro-n-nitrosoguanidine (mnng), 4-nitro-quinoline-1-oxide, and 2-(2-furyl)-3-(5-nitrofuryl)acrylamide. these chemicals were administered at 10 days (late ...	1985	2866598
mauthner neurons survive metamorphosis in anurans: a comparative hrp study on the cytoarchitecture of mauthner neurons in amphibians.	giant medullary neurons were revealed in adult xenopus laevis and rana esculenta following hrp injections to the spinal cord. these neurons were identified as mauthner neurons because (1) they have the same position and orientation as the larval mauthner neurons, i.e., they lie at the level of the viiith nerve root. (2) they have two large dendritic trees that for each species are similar to those of the larval mauthner neurons, (3) they are clearly distinguishable from other large reticular neu ...	1986	3081602
autoneuralization in the amphibian ectoderm--a species-specific and stage-specific phenomenon.	ectoderm from ambystoma is especially prone to undergo 'autoneuralization'. this assertion has led to the maxim that ectoderm from this species is unsuitable for studying cell differentiation. here we report that the degree of neuralization in cultured explants is stage-dependent. control explants from blastulae (stage 8-9) show no neuralization, while explants treated with licl (10 mm) give rise to neuralization in about 70% of the cases. this difference between control and experiment decreases ...	1987	3311847
effect of prolactin on transcutaneous na transport in the japanese newt, cynops pyrrhogaster.	the effect of ovine prolactin (prl) on the electric parameters related to active na transport across the skin was investigated in the japanese newt, cynops pyrrhogaster. spring newts living in a pond or stream for breeding and autumn newts migrating from water to land for hibernation were collected and used for the experiments. autumn newt skin was found to have a higher transepithelial potential difference (tep) and higher resistances to the active na current (rna) and to the shunt pathway (rs) ...	1988	3360287
how is the flagellar length of mature sperm determined? i. comparison of flagellar growth in spermatids between newt and xenopus in vitro.	the kinetics of flagellar growth in round spermatids were compared between xenopus laevis and cynops pyrrhogaster in vitro, the latter of which has about 13 times longer flagella in mature sperm than the former. in both species, more than 90% of the spermatids derived from marked primary spermatocytes grew flagella. in xenopus the average flagellar length increased to 28 microns by the 6th day and then stopped growth, while in the newt, flagellar growth did not stop until reaching 107 microns in ...	1988	3371423
formation of germ layers and roles of the dorsal lip of the blastopore in normally developing embryos of the newt cynops pyrrhogaster.	three-dimensional relationships between tissues during the formation of germ layers were studied in sections of normally developing embryos of the newt, cynops pyrrhogaster. in gastrulae, the inner postinvolution layer was not in direct contact with the outer preinvolution layer as a result of the presence of an intervening layer of cells. only after the formation of the yolk plug, a narrow strip of primitive notochord, which consisted of columnar cells, established a close contact with the cent ...	1988	3404106
factors related to the initiation of cell migration along the inner surface of the blastocoelic wall during amphibian gastrulation.	changes in the quantity of extracellular matrix on the inner surface of the blastocoelic wall (bw) and the adhesiveness of cells to fibronectin were examined in relation to the timing of initiation of cell migration along the bw during gastrulation of the newt, cynops pyrrhogaster. extracellular matrix fibrils were already abundantly present all over the inner surface of the bw prior to the beginning of cell migration. on the other hand, the adhesiveness of cells to fibronectin rapidly increased ...	1988	3409322
total dna transcription in vitro: a procedure to detect highly repetitive and transcribable sequences with trna-like structures.	total dnas from various animals were transcribed in vitro in a hela cell extract, and it was found that one to several discrete rnas were transcribed by rna polymerase iii. with tortoise (geoclemys reevessi) and newt (cynops pyrrhogaster), distinct 6.5s and 8s rnas were transcribed from these respective dnas. representative phage clones carrying the 6.5s and 8s rna genes were isolated from genomic libraries of these animals, and the sequences of these genes were determined. the 5' parts of highl ...	1986	3455763
monoamine-containing basal cells in the taste buds of the newt triturus pyrrhogaster.	monoamine-containing cells were examined by fluorescence histochemistry and electron microscopy. two or three serotonin-like fluorescent cells were located just above the basal lamina and failed to reach the free surface of the taste bud. ultrastructurally this cell type was characterized by the presence of dense-cored vesicles and finger-like cytoplasmic processes. many characteristics of merkel cells were present.	1987	3481961
induction of ocular tumor by nickel subsulfide in the japanese common newt, cynops pyrrhogaster.	chemically induced ocular tumors in amphibians have not been reported previously. in the present study, nickel subsulfide (ni3s2) was administered to lentectomized japanese common newts, cynops pyrrhogaster, by a single injection into the posterior chamber of the right eye (40-100 micrograms ni3s2/newt). control newts received a similar injection of vehicle. malignant melanoma-like tumors developed in the injected eyes of seven of eight ni3s2-treated newts at 9 months (versus none of six control ...	1987	3621207
the spike component of the fertilization potential in the toad, bufo japonicus: changes during meiotic maturation and absence during cross-fertilization.	immature oocytes of the toad, bufo japonicus, inseminated between first- and second-meiotic metaphase, exhibited polyspermy. monospermy occurred when the oocytes had reached second-meiotic metaphase. electrical recording during insemination of the immature oocyte showed fast-rising and slow-rising spikes followed by a gradual shift to a positive membrane potential. the number of fast spikes in each oocyte corresponded well with the number of sperm observed in cytological sections. mature oocytes ...	1987	3653525
cell death during normal gastrulation in the newt, cynops pyrrhogaster.	cells falling off from ectoderm were observed in normally developing gastrulae of the newt, cynops pyrrhogaster, in light microscopic examination. these cells eventually died. the number of such necrotic cells per embryo varied from a few dozen to a few thousand. in embryos with many necrotic cells, the ectoderm was thin, the yolk plug large, and establishment of the neural plate was delayed compared with embryos with fewer necrotic cells. a neural tube of normal size was formed at the tail bud ...	1986	3731278
new translation system of mrna coding for neurotransmitter receptors using oocytes of the newt, cynops pyrrhogaster.	eel electroplax mrna was injected into oocytes of newts (cynops pyrrhogaster) and the injection induced synthesis of a nicotinic acetylcholine receptor in the oocyte membrane. the time course of the induction and dose-response relationship of the receptor were recorded electrophysiologically. the receptor responses and their developmental changes were similar to those of xenopus oocytes injected with eel mrna. newt oocytes lived much longer (7-10 days) than xenopus oocytes (3-4 days) under our e ...	2013	3742236
surface contraction of dividing newt eggs induced by lowering the external ionic strength or ph, or by trypsinization.	as the first cleavage progresses, newt (cynopus pyrrhogaster) eggs deprived of their vitelline membrane grow to expose the new, unpigmented surface to a saline medium full-strength steinberg solution). further exposure of these eggs to sucrose medium resulted in rapid and extensive contraction of the unpigmented surface. in the sucrose medium the contraction continued until the next cleavage, and eventually the eggs divided into many blastomeres. but partial reversal of the contraction was obser ...	1986	3793777
comparative studies on the electric nature of amphibian gonadotropin.	the isoelectric focusing (ief) profiles of pituitary gonadotropic (gth) activity in six species of adult male amphibians were examined in addition to the newt and bullfrog. the gth activity was measured by two radioreceptor assay (rra) systems; one with xenopus laevis testicular homogenate as the receptor preparation, and the other with anolis carolinensis testicular homogenate, both employing 125i-labeled rat fsh as the radioligand, or by a radioimmunoassay (ria) system for bullfrog basic gth ( ...	1985	3874809
effects of temperature on papilloma growth in the newt, cynops pyrrhogaster.	the effects of temperature on skin papillomas of newts (cynops pyrrhogaster) were studied. newts bearing these tumors were maintained for 30 weeks at 4 +/- 1 (s.e.), 10 +/- 1, 13 +/- 2, 25 +/- 1, and 30 +/- 1 degree. the diameters of the papillomas were measured externally. they decreased at 4, 25, and 30 degrees, and increased at 10 and 13 degrees. the effect of temperature on the tumor growth or regression began to appear from around the 10th week. furthermore, when the temperatures were chang ...	1985	3971368
differentiation and distribution of annulate lamellae in growing oocytes in the newt, cynops pyrrhogaster.	stages of oocyte development in cynops pyrrogaster are defined, and changes of annulate lamellae in their fine structure, number, sizes and locations during oogenesis are described. the results show that two different types of annulate lamellae occur during oogenesis. one type differentiates in or at the periphery of vesicle-rich cytoplasm at the early stages of vitellogenesis and increases in number and size. the maximum number of about 40 stacks per median section of oocyte is reached at the s ...	1985	3998684
cell surface changes during cleavage of newt eggs: scanning electron microscopic studies.	scanning electron microscopic studies were carried out on changes of the cell surface during the first cleavage of eggs of the newt, cynopus (triturus) pyrrhogaster. a dense population of elongated microvilli, which initially covered a double line indicating the initial furrow and stress marks running on each side of it, became located inside the pigmented area a little apart from its border with the unpigmented area when this borderline was established. this finding, together with data of carbo ...	2014	4039355
the mast cells in the brain of the triturus pyrrhogaster (boie). i. the histologic studies.		1968	4181658
a nephroblastoma in a fire-bellied newt, cynops pyrrhogaster.		1970	4321086
[neural control of the terminal of the hindgut of triturus pyrrhogaster].		1974	4477310
merits of the japanese newt, cynops pyrrhogaster pyrrhogaster, as an experimental animal, especially for the study of transplantation immunity.		1973	4609273
monoamine oxidase in the neurohypophysis of the newt (cynops pyrrhogaster pyrrhogaster), the toad (bufo bufo japonicus) and the tortoise (clemmys japonica).		1972	4623962
spontaneous epidermal tumor in an adult newt, cynops pyrrhogaster.		1973	4689907
electron microscopic study on the parathyroid gland of the parathormone-injected newt, triturus pyrrhogaster (boie).		1973	4740812
self-differentiation of the heart rudiment of the newt (cynops pyrrhogaster).		1973	4797323
wave of stiffness propagating along the surface of the newt egg during cleavage.	in the eggs of the newt, cynops (triturus) pyrrhogaster, change in stiffness of the cortex was measured in various regions at the time of the cleavage. measurements were performed by mitchison and swann's cell elastimeter method with a modification, in which two fine pipettes were attached to the surface of one egg at the same time, in order to compare the rigidity of two regions. the stiffness of the cortex changed very little before the start of the first cleavage. however, just before the app ...	1974	4809240
electrical coupling between fat cells in newt fat body and mouse brown fat.	white fat from the newt, triturus pyrrhogaster, fat body, and brown fat from the interscapular fat pad of newborn mice have been tested for the presence of low-resistance intercellular junctions. 42 pairs of amphibian fat cells and 15 pairs of mammalian brown fat cells were found to be "electrically coupled." in most of these cases intracellular deposition of a dye, niagara sky blue: 6b, was used to supplement and confirm direct observations of impalements. coupling was often difficult to find i ...	1971	4938627
electron-microscopic observations on the finer structure of basophilic granulocytes of newt (triturus pyrrhogaster).		2016	4960340
origin of histones, and relation between nuclear histones and cytoplasmic basic proteins in early development of japanese newt, triturus pyrrhogaster.		1972	5037000
ultrastructural change in the parathyroid gland of the phosphate treated newt, triturus pyrrhogaster (boié).		1971	5168592
experiments on a spontaneously orginated visceral tumor in the newt, triturus pyrrhogaster.		1970	5278142
[the electron microscopic study on the functional area of the digestive epithelial cell membrane in newt, triturus pyrrhogaster].		1971	5290269
alkaline phosphatase activity in the regenerating limb of the adult newt triturus pyrrhogaster.		1969	5384492
cultivation in vitro of the testis cord of the newt, triturus pyrrhogaster.		1969	5392793
an electron microscopic study on the guanophore in the iris of the newt, triturus pyrrhogaster (boié).		1969	5395640
are the parathyroid glands necessary to the life of the newt, cynops pyrrhogaster?		1969	5395934
behaviour of histones and cytoplasmic basic proteins during embryogenesis of the japanese newt, triturus pyrrhogaster.		1969	5408616
electron microscopic study on the parathyroid gland of the newt triturus pyrrhogaster (boié) in natural hibernation.		1970	5442608
regional histone changes in embryos of the newt, triturus pyrrhogaster, during early development.		1970	5459824
ultrasturcture of the parathyroid gland of the newt, triturus pyrrhogaster (boié) in the spring season.		1970	5468683
lymphosarcomatous disease of the newt, triturus pyrrhogaster.		1970	5538539
mast cells and histamine in a newt, triturus pyrrhogaster boié.		1968	5711878
differentiation capacity of the marginal zone in the morula and blastula of triturus pyrrhogaster.		1967	6075513
in vitro analyses of wolffian lens regeneration: differentiation of the regenerating lens rudiment of the newt, triturus pyrrhogaster.		1967	6075514
histochemical and electrophoretic studies of esterase in the regenerating forelimb of the adult newt, triturus pyrrhogaster.		1967	6075515