Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| retinotopic analysis of fiber pathways in the regenerating retinotectal system of the adult newt cynops pyrrhogaster. | retinotopic analysis of the pathways of regenerating retinal fibers within the optic tract and in the tectum of an adult newt was performed by selective labeling of the retinal fibers with horseradish peroxidase. at the tenth week of regeneration, all the regenerating retinal fibers from different retinal quadrants had terminal arbors nearly at the parts of the tectum innervated normally by those quadrants. the pathways for individual retinal fibers, however, were greatly disorganized within the ... | 1981 | 6162521 |
| retinotopic analysis of fiber pathways is amphibians. i. the adult newt cynops pyrrhogaster. | the possibility that pathways of retinal fibers within the optic tract and the tectum of the adult newt are retinotopic was examined by selective labeling of the retinal fibers with horseradish peroxidase. within the optic tract fibers from the ventral, temporal and dorsal retinal quadrants were ordered from the dorsal to ventral edges of th optic tract. the nasal retinal fibers exhibited two different pathways. the fibers from the dorsonasal retina ran along the ventral edge of the optic tract, ... | 1981 | 6162523 |
| follicle-stimulating hormone (fsh) receptors in the testis of the newt, cynops pyrrhogaster, and comparison of temperature dependency of the receptors with those of the other vertebrates. | 1980 | 6245987 | |
| [evaluation of amputation techniques for the study of limb regeneration in the newt and toad]. | a comparison between forelimb amputations through the radius-ulna and the humerus was made in the adult newt, cynops pyrrhogaster pyrrhogaster and the young toad, xenopus laevis. newts regenerated their forelimbs after the amputations and the new parts resembled the old in structure and function. toads regenerated their forelimbs incompletely after the amputations. the new parts lacked joints and fingers showing a simply elongate pattern. the effect of re-amputation of exposed bone on the regene ... | 1984 | 6468505 |
| lack of cellular differentiation with neoplastic-like proliferation in the limbs of the newt cynops pyrrhogaster. | we report a case of a neoplastic-like proliferation of epidermal cells in the limbs of an adult newt. the undifferentiated cell mass infiltrated the mesodermal tissues. possible effects of this event on limb regeneration are discussed. | 2003 | 6486729 |
| comparative study of extracellular fibrils on the ectodermal layer in gastrulae of five amphibian species. | previous studies have shown the presence of a network of extracellular fibrils on the inner surface of the ectodermal layer of the ambystoma maculatum gastrulae. the alignment of the network along the blastopore-animal pole axis has suggested that the network of fibrils guides the migrating mesodermal cells in gastrulae by contact guidance. we have also shown that these fibrils can be deposited on substrata by explanted embryonic fragments and that substrata conditioned in this manner support di ... | 1983 | 6602807 |
| cadmium, copper and zinc-binding protein (metallothionein) in the liver of the water lizard triturus pyrrhogaster. | a low-mr copper (cu) and zinc (zn)-binding protein was present in the liver of a control water lizard triturus pyrrhogaster. cadmium (cd) accumulated in the liver of the animals after intramuscular injections of cd salt and was bound to cu- and zn-binding protein of a single isoform that had properties characteristic of metallothionein (mt). effects of cd loading on several essential elements in the liver and kidney were also determined. | 1984 | 6719500 |
| seasonal variation in pituitary gonadotropin in the adult male newt, cynops pyrrhogaster pyrrhogaster, revealed by isoelectric focusing technique and radioreceptor assay. | the seasonal variation in pituitary gonadotropin in the adult male newt, cynops pyrrhogaster pyrrhogaster was investigated by means of isoelectric focusing (ief) coupled with radioreceptor assay (rra), which employed anolis or xenopus testicular homogenates as receptors and 125i-rat fsh as radioligand. in the anolis rra system, the standard curve was obtained with 0.125-16 ng/tube of niamdd rat fsh i-3. purified preparations, chicken lh ief-1, chicken fsh agchd11113a and bullfrog basic gonadotro ... | 1981 | 6796397 |
| cell surface properties of amphibian embryonic cells. | gastrula and neurula embryos of cynops pyrrhogaster were dissociated into cell suspensions with ethylenediaminetetraacetic acid (edta), trypsin, and solution. the cells were cultured in niu-twitty's balanced salt solution and their aggregates were examined histologically. the results indicated that the capacity of amphibian embryonic cells for aggregate formation, sorting out, and notochord differentiation was not suppressed by edta and alkali treatments. trypsin treatment, however, virtually su ... | 1980 | 6796637 |
| studies on the development of melanophores in in vitro cultured amphibian neural plates. | various parts of neural plates of japanese newt (cynops pyrrhogaster) neurula embryos were cultured alone in drops of culture media (niu-twitty's balanced salt solution or modified leibovitz l-15 medium) with or without fetal calf serum (fcs). although none of the parts gave rise to melanophores in a medium without fcs, some produced melanophores in a medium with fcs. the localization of melanophore-producing areas in the neural plates corresponded to that of tada's (1944) findings. the assumpti ... | 1983 | 6825926 |
| the degradation of urate in liver peroxisomes. association of allantoinase with allantoicase in amphibian liver but not in fish and invertebrate liver. | allantoinase and allantoicase were co-purified from frog (rana catesbeiana) liver. the ratio of the two enzyme activities remained constant during purification and was unchanged by a variety of treatments of the purified enzyme. these results suggest that allantoinase and allantoicase are located in the same protein. it was found that the two hepatic enzyme activities are also associated with the same protein in other frogs (xenopus laevis and rana nigromacultata), tadpoles (r. catesbeiana), and ... | 1983 | 6833275 |
| the structure of the kidney of japanese newts, triturus (cynops) pyrrhogaster. | the construction of renal lobules in triturus (cynops) pyrrhogaster was studied by reconstruction from serial semithin sections, and the structure of nephrons, collecting ducts and ureters was investigated by means of light and electron microscopy. in t. pyrrhogaster the kidney was mesonephros in construction; renal lobules were arranged segmentally and each of them sent one ureter. male ureters ran caudally and met together before joining the wolffian duct. in renal lobules, long collecting duc ... | 1983 | 6837932 |
| seasonal changes in plasma testosterone and 5 alpha-dihydrotestosterone levels in the adult male newt, cynops pyrrhogaster pyrrhogaster. | seasonal changes in plasma levels of testosterone (t) and 5 alpha-dihydrotestosterone (dth) were examined in the adult male japanese red-bellied newt. the concentration of plasma t increased significantly (p less than 0.05) from january to february and decreased drastically from april to july when it reached its minimum. after the summer decline, plasma t increase rapidly from july to october (p less than 0.05) and reached its maximum in october. concerning the seasonal fluctuation of plasma dht ... | 1983 | 6884270 |
| effect of hypophysectomy and starvation on the fine structure of vitellogenic oocytes in the newt, triturus pyrrhogaster (laur). | hypophysectomy and starvation in triturus pyrrhogaster result in a similar ultrastructural pattern of follicular atresia. the first detectable change in the oocytes is decrease in the size and number of microvilli. subsequently the yolk precursor bodies (ypb) disappear from the micropinocytotic vesicles and the mitochondria degenerate. finally the yolk platelets undergo decomposition. the smaller yolk platelets disintegrate by granulation, vacuolation and lobule formation. the larger platelets, ... | 1982 | 6892135 |
| seasonal and geographical changes of spontaneous skin papillomas in the japanese newt cynops pyrrhogaster. | the occurrence of spontaneous skin papillomas in japanese newts (cynops pyrrhogaster) from niigata prefecture in northern japan was monitored over four seasons covering a period of 2 years. of 13,613 newts, 249 were found to possess papillomas. the percentage of newts with papillomas was highest in autumn, ranging from 1.93 to 5.45% of the total average. these values were more than four times as high as values obtained in the other three seasons (0.16 to 0.50%). a total of 12,167 newts were coll ... | 1982 | 7105040 |
| behaviour of annulate lamellae during the maturation of oocytes in the newt, cynops pyrrhogaster. | the distribution of annulate lamellae, electron-dense masses, rough endoplasmic reticulum, and golgi complexes in longitudinal sections of newt oocytes at several stages of progesterone-induced maturation was recorded with an electron microscope equipped with a drawing device. annulate lamellae in full-grown oocytes occur in close contact with electron-dense masses and the nuclear envelope and elsewhere. stacks of annulate lamellae increase in number for 6 h after progesterone treatment. meanwhi ... | 1982 | 7142895 |
| the photoreceptor cell in the pineal organ of the japanese common newt. | 1982 | 7151960 | |
| creeping locomotion of the endodermal cells dissociated from gastrulae of the japanese newt, cynops pyrrhogaster. | 1981 | 7238592 | |
| temporal pattern of cleavage and the onset of gastrulation in amphibian embryos developed from eggs with the reduced cytoplasm. | fertilized eggs of the japanese newt, cynops pyrrhogaster, were divided into two or four equal-sized parts with fine glass rods before the first cleavage. in such cases one of the egg fragments, at least, proceeds to cleavage and gastrulates. the temporal pattern of cell division and the onset of gastrulation in such half or quarter embryos were investigated and compared with normal development. the following results were obtained: (1) desynchronization starts two divisions earlier in quarter em ... | 1981 | 7276823 |
| meiosis of primary spermatocytes and early spermiogenesis in the resultant spermatids in newt, cynops pyrrhogaster in vitro. | dissociated spermatogenic cells were cultivated within the collagen matrix at low cell density. the largest cell type in the culture was identified as the primary spermatocytes by their size and the morphological characteristics revealed by ultra-thin sections. chromosome analysis showed that about 90% of the cells examined were either in first or second meiosis. within the collagen matrix, the fates of 282 single primary spermatocytes at meiotic stage in diakinesis or metaphase were followed. i ... | 1981 | 7308609 |
| electron microscope study of vertebrate liver innervation. | liver fine structure was studied in various groups of vertebrates to reveal intrahepatic nerves. nerve fibers were found in the connective tissue of the liver in all mammals, birds, and reptiles studied (japanese monkey, crab-eating monkey, rabbit, guinea pig, rat, golden hamster, pigeon, japanese quail, and turtle, pseudemys scripta). nerve fibers also made direct contact with hepatocytes in these animals except for the rat and the golden hamster. intrahepatic nerves were rare or absent in amph ... | 1981 | 7316686 |
| [differentiation of granulocytes in the newt (triturus pyrrhogaster), with special reference to the granule formation (author's transl)]. | 1980 | 7424490 | |
| neuroepithelial endocrine and nervous system in the respiratory tract of cynops pyrrhogaster with special reference to the distribution of nitric oxide synthase and serotonin. | the respiratory tract of urodeles harbours an intramural nerve network comprising an innervated system of neuroepithelial endocrine (nee) cells. however, striking differences have been noted between phylogenetically closely related species. zamboni- or formaldehyde-fixed whole-mount preparations and sections of the saclike lungs of a japanese salamander, cynops salamander, cynops pyrrhogaster, have been investigated for the immunocytochemical detection of nitric oxide synthase (nos), serotonin ( ... | 1994 | 7529073 |
| atomic force microscope observations of otoconia in the newt. | calcitic and aragonitic otoconia from the japanese red-bellied newt, cynops pyrrhogaster, were examined using an atomic force microscope. the surface structure of both otoconial polymorphs consisted of arrays of elements approximately 50 nm in diameter. elements were generally round and were separated by shallow depressions of no more than 20 nm. the elements are suggested to be single crystals of calcium carbonate. the relationship of these observations to theories of otoconial genesis is discu ... | 1995 | 7559167 |
| development of the otolith organs and semicircular canals in the japanese red-bellied newt, cynops pyrrhogaster. | the sequence in which the otoliths and semicircular canals and their associated sensory epithelia appear and develop in the newt are described. three-dimensional reconstruction of serial sections through the otic vesicle of newt embryos from stages 31 through 58 demonstrate the first appearance, relative position and growth of the otoliths. a single otolith is first seen in stage 33 embryos (approximately 9 days old); this splits into separate utricular and saccular otoliths at stage 40 (13 days ... | 1995 | 7642454 |
| the morphogenic features of otoconia during larval development of cynops pyrrhogaster, the japanese red-bellied newt. | otoconia are calcified protein matrices within the gravity-sensing organs of the vertebrate vestibular system. mammalian otoconia are barrel-shaped with triplanar facets at each end. reptilian otoconia are commonly prismatic or fusiform in shape. amphibians have all three otoconial morphologies, barrel-shaped otoconia within the utricle, with prismatic and fusiform otoconia in the saccule. scanning electron microscopy revealed a sequential appearance of all three otoconial morphologies during la ... | 1995 | 7642456 |
| calcium-containing, smooth-surfaced endoplasmic reticulum and vacuoles in cells of the blastopore-forming region during gastrulation of the newt, cynops pyrrhogaster. | ultrastructural changes in cells of the blastopore-forming region (bfr) were examined during gastrulation of the newt, cynops pyrrhogaster. smooth-surfaced endoplasmic reticulum (ser), tubular in shape and with two types of vacuole, empty vacuoles and multilamellar vacuoles, appeared in cells of the bfr at the beginning of formation of the blastopore. the extent of the tubular ser increased during formation of the blastopore. with the deepening of the blastoporal groove, the tubular ser and mult ... | 1995 | 7645763 |
| development and application of a homologous radioimmunoassay for xenopus prolactin. | a specific and sensitive homologous radioimmunoassay (ria) for xenopus prolactin (xprl) was developed. prl isolated from x. laevis pituitary glands was used for generating antiserum in a rabbit, for radioligand and for the standard. pituitary homogenates and plasma from adult xenopus produced displacement curves parallel to the xprl standard. plasma from hypophysectomized xenopus showed negligible cross-reactivity. purified prls from other amphibian species such as the bullfrog (rana catesbeiana ... | 1995 | 7657154 |
| proliferation of newt spermatogonia by mammalian fsh via sertoli cells in vitro. | our previous studies showed that mammalian follicle-stimulating hormone (fsh) stimulated the proliferation and differentiation of secondary spermatogonia into primary spermatocytes in organ culture of testes fragments from cynops pyrrhogaster. to elucidate how fsh stimulates spermatogonial proliferation, we studied the interaction of spermatogonia with somatic cells in the presence or absence of fsh in cultures of aggregated cells derived from fractionated cell populations. when spermatogonia or ... | 1995 | 7673874 |
| promotion of differentiation of newt primary spermatocytes into spermatids by mammalian fsh via sertoli cells. | our previous studies showed that mammalian follicle-stimulating hormone (fsh) promoted the differentiation of primary spermatocytes into elongated spermatids in organ culture of testes fragments from cynops pyrrhogaster. to elucidate the mechanism of fsh action, in this study the testes in the primary spermatocyte stage were dissociated and fractionated into germ and somatic cells, the latter comprising more than 80% sertoli cells. radioreceptor assays showed that fsh bound to somatic cells, ver ... | 1995 | 7673875 |
| mammalian follicle-stimulating hormone stimulates dna synthesis in secondary spermatogonia and sertoli cells in organ culture of testes fragments from the newt, cynops pyrrhogaster. | we previously showed in organ culture of testes fragments from cynops pyrrhogaster that mammalian follicle-stimulating hormone (fsh) stimulates secondary spermatogonia to differentiate into primary spermatocytes. in this report, we demonstrate in organ culture that fsh stimulates dna synthesis in secondary spermatogonia and sertoli cells: the numbers of secondary spermatogonia and sertoli cells incorporating 5-bromo-2'-deoxyuridine (brdu) throughout the culture period in the presence of fsh were ... | 1994 | 7881917 |
| sodefrin: a female-attracting peptide pheromone in newt cloacal glands. | a decapeptide called sodefrin was isolated from the abdominal gland of the cloaca of the male red-bellied newt, cynops pyrrhogaster. the native peptide, as well as the synthetic one, had a female-attracting activity. sodefrin was found in the apical portion of the epithelial cells of the abdominal gland. sodefrin is apparently species specific because it did not attract females of cynops ensicauda. this is the first amphibian pheromone to be identified and the first peptide pheromone identified ... | 1995 | 7886452 |
| initiation and stimulation of spermatogenesis in vitro by mammalian follicle-stimulating hormone in the japanese newt, cynops pyrrhogaster. | in order to elucidate the molecular mechanisms by which spermatogenesis is regulated, especially the roles of hormones and somatic cells in the initiation and promotion of spermatogenesis, we developed an organ culture system with a chemically defined medium. when newt testes fragments rich in secondary spermatogonia were cultured in control medium for three weeks, most of the testicular cysts still remained as secondary spermatogonia. on the other hand, in the medium supplemented with follicle- ... | 1994 | 7981029 |
| ultrastructure of the olfactory organ of the newt, cynops pyrrhogaster. | the ultrastructure of the nasal sacs of the japanese newt, cynops pyrrhogaster, was studied by scanning and transmission electron microscopy. the paired nasal sacs of the newt are dorsoventrally flattened with a lateral nasal sinus off the main cavity of each sac. throughout each sac is a series of ridges and grooves. in the main cavity, sensory epithelium with ciliated and microvillous receptor cells lines the grooves, and a thin, ciliated non-sensory epithelium lines the ridges. secretory glan ... | 1994 | 8059972 |
| hormonal control of response to and secretion of sex attractants in japanese newts. | hormonal control of sexual chemoattraction in the newt, cynops pyrrhogaster, was investigated by a water preference test. sexually inert newts injected with prolactin (prl) and human chorionic gonadotropin (hcg) in combination preferred the water in which newts of the opposite sex had been kept, whereas saline-injected specimens did not. this indicates that prl and hcg enhance the response of the newts to attractant(s) secreted by the opposite sex. the water in which prl plus hcg-treated newts h ... | 1994 | 8190778 |
| motion sickness in amphibians. | we explored the question of whether amphibians get motion sickness by exposing anurans (frogs) and urodeles (salamanders) to the provocative stimulus of parabolic aircraft flight. animals were fed before flight, and the presence of vomitus in their containers after flight was used to indicate motion-induced emesis. none of the species that we studied vomited during the 8 to 10 parabolas of each flight. however, at least one specimen from each of the anuran species rana rugosa, rana nigromaculata ... | 1993 | 8216158 |
| the egg nucleus regulates the behavior of sperm nuclei as well as cycling of mpf in physiologically polyspermic newt eggs. | the possible role of the egg nucleus in regulating the behavior of sperm nuclei and the cycling of maturation-promoting factor (mpf) was investigated in the physiologically polyspermic eggs of the newt cynops pyrrhogaster. many sperm entered all areas of the egg, but only one sperm pronucleus, the principal sperm pronucleus, moved to the center of the animal hemisphere to form a zygote nucleus with the egg pronucleus. all sperm and egg pronuclei synthesized dna, but the zygote nucleus completed ... | 1993 | 8224532 |
| hormonal induction of male courtship behavior in the japanese newt, cynops pyrrhogaster. | in the breeding season, the sexually mature male newt, cynops pyrrhogaster, vibrates the tail in front of the female at an early stage of courtship. effects of prolactin (prl), gonadotropin (gth), and sex steroids on this behavior were investigated in the male paired with the female receiving prl and gth. the behavior was elicited in the sexually inert male by injections of prl of bovine, ovine, or bullfrog origin and human chorionic gonadotropin or bullfrog lh and fsh in combination. the effect ... | 1993 | 8294119 |
| non-invasive assessment of otolith formation during development of the japanese red-bellied newt, cynops pyrrhogaster. | pre-mated adult female newts and embryos have been flown on the international microgravity laboratory-2 (iml-2) space shuttle flight in 1994 (wiederhold et al., 1992b). with the specimens available from this flight, the calcification of otoliths, ulna, radius and backbone of the flown larvae and adult newts were analyzed. the experiments presented here studied the development of the otoliths on the ground. otoliths of living newts, from embryo to adult, were observed in situ with the application ... | 1995 | 8575997 |
| comparison of mauthner cell size in sexually developed and undeveloped male red-bellied newts. | differences in mauthner (m) cell size were examined in sexually developed and undeveloped male red-bellied newts, cynops pyrrhogaster. the mean areas of nuclei and cell bodies of m cells and mean maximum and minimum diameters of the cell bodies in the sexually developed males were significantly larger than those in the sexually undeveloped ones. in the hypophysectomized male newts, all these parameters were not significantly different from those in the sexually undeveloped ones. these values wer ... | 1995 | 8586962 |
| [new sex pheromone isolated from the abdominal glands of male newt, cynops pyrrhogaster]. | sodefrin, a novel decapeptide which attracts female newts, cynops pyrrhogaster was isolated from the abdominal gland of the male of the same species. synthetic sodefrin was tested for its activity with sexually active females and males and sexually inert females. it attracted only sexually active females. the effect of sodefrin was blocked by a bilateral nostril plugging with cotton balls soaked in melted vaseline. immunoelectronmicroscopic study using antiserum against sodefrin revealed that so ... | 1995 | 8763038 |
| activin treated urodele ectoderm: a model experimental system for cardiogenesis. | the tissue interactions which comprise the inductive phenomena associated with urodele heart morphogenesis are relatively well understood. in order to take full advantage of the experimental potential of this system formulation of an in vitro tissue culture system would be very helpful. herein are described conditions for culturing cynops pyrrhogaster early gastrula ectoderm tissue in the presence of the peptide growth factor activin. two-week old explant cultures frequently displayed beating he ... | 1996 | 8877444 |
| radioimmunoassay of a newt sex pheromone, sodefrin, and the influence of hormones on its level in the abdominal gland. | a specific and sensitive radioimmunoassay (ria) was developed for the measurement of sodefrin, a female-attracting decapeptide pheromone of the red-bellied newt, cynops pyrrhogaster. sodefrin synthesized according to the amino acid sequence of native sodefrin, isolated from the abdominal glands of the cloaca of the male newt, was used as a reference standard. an antiserum to sodefrin was produced by immunizing a rabbit with synthetic sodefrin that was extended on its c-terminus with cys coupled ... | 1996 | 8954769 |
| involvement of endogenous prolactin in the expression of courtship behavior in the newt, cynops pyrrhogaster. | in order to ascertain the involvement of endogenous prolactin (prl) in the expression of courtship behavior by the male newt, cynops pyrrhogaster, antiserum against homologous prl was administered to male newts, which had been exhibiting courtship behavior in the field and had been taken to the laboratory. the effect of the antiserum on the preference of terrestrial over aquatic habitats also was investigated. within 24 hr of the first injection of antiserum, both incidence and frequency of cour ... | 1996 | 8998963 |
| primary structures of sperm-specific basic nuclear proteins and gene expression in japanese newt, cynops pyrrhogaster. | electrophoretic analyses of acid extracts from mature sperm of newt, cynops pyrrhogaster, on acid/urea/triton x-100 polyacrylamide gel showed the exclusive occurrence of sperm-specific nuclear basic proteins (sbps), which moved faster than somatic histones on the gel. these sbps were eluted separately by reversed phase-high-performance liquid chromatography as two large peaks and a few small peaks. of these, only the small peaks disappeared with treatment of the acid extracts with alkaline phosp ... | 1997 | 9041126 |
| effect of protein phosphatase inhibitors on cleavage furrow formation in newt eggs: inhibition of normal furrow formation and concomitant induction of furrow-like dents. | the effects of three protein phosphatase inhibitors, okadaic acid, calyculin a and tautomycin, on the formation of cleavage furrows and the induction of furrow-like dents in the egg of the newt, cynops pyrrhogaster, were examined. solutions of the individual compound were injected into the animal hemisphere of one of the two presumptive blastomere regions of the embryo during the first cleavage. injection of a solution containing any of the chemicals often disturbed the formation of a normal fur ... | 1997 | 9108337 |
| changes in microtubule structures during the first cell cycle of physiologically polyspermic newt eggs. | the unfertilized egg of the newt, cynops pyrrhogaster, has a second meiotic spindle at the animal pole and numerous cortical cytasters. after physiologically polyspermic fertilization, all sperm nuclei incorporated into the egg develop sperm asters, and the cortical cytasters change into bundles of cortical microtubules. the size of the sperm asters in the animal hemisphere is approximately 5.6-fold larger than that in the vegetal hemisphere. only one sperm nucleus moves toward the center of the ... | 1997 | 9136124 |
| female-attracting pheromone in newt cloacal glands. | it has been postulated that male newts emit pheromones that attract females of the same species. female newts of the species cynops pyrrhogaster were attracted to water in which sexually active conspecific males had been kept, but not to water in which abdominal gland-ablated males had been kept, indicating that the attracting pheromone was secreted by or through the abdominal gland of the cloaca. an attempt has been made to isolate and characterize the female-attracting pheromone in the abdomin ... | 1997 | 9370206 |
| innervation of two peptidergic (substance p and calcitonin gene-related peptide) nerves in the cerebral arteries and choroid plexus of the japanese newt (triturus pyrrhogaster). | the pattern of cerebrovascular substance p (sp) and calcitonin gene-related peptide (cgrp) immunoreactive (-ir) innervation was investigated in the newt. sp-ir nerves supplying the cerebral arterial tree and choroid plexus were positive for cgrp, but negative for vasoactive intestinal polypeptide or neuropeptide y. it is suggested that cerebrovascular sp- and cgrp-ir axons are sensory in nature. the supply of sp- and cgrp-ir nerves to the major cerebral arteries is relatively poor. nevertheless, ... | 1997 | 9409510 |
| [elucidation of the mechanism of retinal degeneration and regeneration and the prospects for its clinical application]. | in order to obtain the basic knowledge necessary to develop therapeutical intervention for blindness due to the damaged retina and optic nerve, the mechanism of retinal degeneration and regeneration in an amphibian model, cynops pyrrhogaster, was studied. in the retinal degenerative process following enucleation and reimplantation of the eye ball, evidence was found for active cell death of neural retinal cells. as the degeneration proceeded, musashi, an ribonucleic acid (rna)-binding protein, s ... | 1997 | 9436360 |
| ultrastructure of the endolymphatic sac in the larva of the japanese red-bellied newt cynops pyrrhogaster. | the ultrastructure of the endolymphatic sac (es) of the late stage larva of the japanese red-bellied newt, cynops pyrrhogaster (stage 57), was examined by light and transmission electron microscopy. the two endolymphatic sacs are located at the dorsal-medial side of the otic vesicle on the dorsal-lateral side of the midbrain in the cranial cavity. the wall of the sac is composed of a layer of cubical epithelial cells with loose, interposed intercellular spaces. the sac contains a large luminal c ... | 1998 | 9477311 |
| changes in cyclin b during oocyte maturation and early embryonic cell cycle in the newt, cynops pyrrhogaster: requirement of germinal vesicle for mpf activation. | when full-grown oocytes of the newt cynops pyrrhogaster were treated with progesterone in o-r2 solution containing antibiotics, approximately 85% of the oocytes completed meiosis synchronously. maturation-promoting factor (mpf) activity appeared just before germinal vesicle breakdown (gvbd) and the oocytes maintained high mpf activity throughout metaphase i and metaphase ii of meiosis. a slight decrease of mpf activity was observed at the first polar body emission. the distribution of cyclin b1 ... | 1998 | 9520324 |
| difference between dorsal and ventral iris in lens producing potency in normal lens regeneration is maintained after dissociation and reaggregation of cells from the adult newt, cynops pyrrhogaster. | in wolffian lens regeneration, lentectomized newt eye can produce a new lens from the dorsal marginal iris, but the ventral iris has never shown such capabilities. to investigate the difference of lens regenerating potency between dorsal and ventral iris epithelium at the cellular level, a transplantation system using cell reaggregates was developed. two methods were devised for preparing the reaggregates from pigmented iris epithelial cells. one was rotating cells in an agar-coated multiplate o ... | 1998 | 9563906 |
| development of the endolymphatic sac and duct in the japanese red-bellied newt, cynops pyrrhogaster. | the development and maturation of the endolymphatic sac (es) and duct (ed) were studied in the newt cynops pyrrhogaster. the es first appears as an oval capsule at the dorsal-medial tip of the otic vesicle at stage 39, about 11 days after oviposition. the es consists of polymorphous epithelial cells with a minimum of cytoplasm. the intercellular space (is) between the epithelial cells is narrow and has a smooth surface. at stage 44, the size of the es increases as many vacuoles in the is become ... | 1998 | 9606061 |
| patterns of gene expression in the core of spemann's organizer and activin-treated ectoderm in cynops pyrrhogaster. | the presumptive pharyngeal endoderm region of the cynops early gastrula induces head or trunk-tail structures in sandwich culture. activin-treated ectoderm can mimic this phenomenon at least at the histological level. the patterns of expression of organizer-specific genes were examined to compare these two inductive materials at the molecular level. a chordin cdna clone from cynops pyrrhogaster (cychd) was isolated by reverse transcription-polymerase chain reaction (rt-pcr). cychd mrna was first ... | 1998 | 9639361 |
| production of otoconia in the endolymphatic sac in the japanese red-bellied newt, cynops pyrrhogaster: light and transmission electron microscopic study. | the formation of otoconia in the endolymphatic sac (es) of the larval newt, cynops pyrrhogaster, has been studied by light and transmission electron microscopy. some of the epithelial cells of the es contain an abundance of swollen vesicles, golgi complexes, rough endoplasmic reticula and ribosomes at the late larval stages 50 and 51, approximately 26-30 days after eggs are laid. five days later, at stage 52, crystals are present in the vacuoles between the epithelial cells. serial sections indi ... | 1998 | 9726680 |
| cloning of cdnas for the pituitary glycoprotein hormone alpha subunit precursor molecules in three amphibian species, bufo japonicus, rana catesbeiana, and cynops pyrrhogaster. | we have isolated cdna clones encoding molecules of putative glycoprotein hormone alpha subunit precursors from their pituitary cdna libraries for a toad, bullfrog and newt. the insert of the isolated toad cdna was 562 bp long containing the 5'-untranlated, coding and 3'-untranslated regions of 38, 363 and 161 bp, respectively. the insert of the bullfrog cdna was 604 bp long containing the 5'-untranslated, coding and 3'-untranslated regions of 70, 366, and 168 bp, respectively. in the newt, a com ... | 1998 | 9748402 |
| isolation and characterization of a gene expressed mainly in the gastric epithelium, a novel member of the ep37 family that belongs to the betagamma-crystallin superfamily. | ep37 family proteins are non-lens members of the betagamma-crystallin superfamily, of which expression is observed in integumental tissues of the japanese newt, cynops pyrrhogaster. in the present study, a gene was isolated that has high homology with ep37 and is transcribed mainly in the gastric epithelial cells and hence designated gep. the predicted amino acid sequence of the gep cdna contains four betagamma-crystallin motifs in the n-terminal half, as is the case in the integumental ep37 pro ... | 1998 | 9783472 |
| a critical role for the optic vesicle in lens development; a reinvestigation of free lens formation in cynops pyrrhogaster. | the role of the optic vesicle in lens development was reinvestigated in cynops pyrrhogaster. to study the necessity for the optic vesicle in early lens development, the optic anlages of stage 17-27 embryos were ablated and the frequency of free lens formation was examined with lens specific markers. free lens formation was not observed when operations were performed prior to contact between the head surface epidermis and the optic vesicle (stages 17-18). on the contrary, free lens formation occu ... | 1998 | 9810703 |
| cloning of cdna for newt wt1 and the differential expression during spermatogenesis of the japanese newt, cynops pyrrhogaster. | to investigate the function of wilms' tumor 1 (wt1) during spermatogenesis, cdna for newt wt1 homolog was cloned and the expression of wt1 in newt testes was examined. the cdna is 2089 bp in length and encodes 426 amino acid (aa) residues. the deduced aa sequence shares 76 and 79% homology with human and xenopus wt1, respectively. northern blot analysis shows that wt1 mrna, 3.2 and 4.5 kb in length, are expressed in the testis and kidney. both wt1 mrna species are detected in various stages of s ... | 1998 | 9865970 |
| sodefrin: a novel sex pheromone in a newt. | the abdominal gland in the male red-bellied newt, cynops pyrrhogaster, is the source of a female-attracting pheromone. an attempt was made to isolate and characterize the female-attracting pheromone in the abdominal glands of male newts. the active substance, named sodefrin (from the japanese 'sodefuri' which means 'soliciting') has been isolated and shown to be a novel decapeptide with the sequence, ser-ile-pro-ser-lys-asp-ala-leu-leu-lys. its minimum effective concentration in water is 0.1-1.0 ... | 1999 | 10051096 |
| elevation of plasma prolactin concentrations by low temperature is the cause of spermatogonial cell death in the newt, cynops pyrrhogaster. | temperature plays an important role in reproduction of urodeles. spermatogenesis in newts is arrested when the environmental temperature lowers. we found that transfer of newts, cynops pyrrhogaster, to low temperature (8 and 12 degrees c) caused cell death of spermatogonia just before meiosis and elevation of prolactin concentration in the newt plasma. injection of a dopamine antagonist (pimozide), which is known to increase the plasma prolactin concentration, to the newt caused significant incr ... | 1999 | 10082633 |
| rise of intracellular ca2+ level causes the decrease of cyclin b1 and mos in the newt eggs at fertilization. | unfertilized eggs of the newt, cynops pyrrhogaster, are arrested at the second meiotic metaphase, with activity of the m-phase promoting factor (mpf) maintained at a high level. after fertilization, the eggs resume the cell cycle, and emit the second polar body. when the change in [ca2+]i in the fertilized eggs was monitored by aequorin, an early increase in [ca2+]i was observed 5-10 min after insemination and continued for about 30 sec. a late increase in [ca2+]i then occurred 10-15 min after f ... | 1999 | 10369395 |
| sperm surface heparin/heparan sulfate is responsible for sperm binding to the uterine envelope in the newt, cynops pyrrhogaster. | the sperm-binding properties of egg envelopes are investigated in the newt, cynops pyrrhogaster. sperm binding was only seen on the uterine envelope when acrosome-reacted sperm were inseminated. no acrosome-intact sperm bound to the envelopes. by scanning electron microscopic observation, acrosome-reacted sperm were revealed to bind to a seat-like structure present on the surface of the uterine envelope. sperm binding to the uterine envelope was inhibited by treatment of eggs with heparin or hep ... | 1999 | 10445507 |
| endoderm differentiation and inductive effect of activin-treated ectoderm in xenopus. | when presumptive ectoderm is treated with high concentrations of activin a, it mainly differentiates into axial mesoderm (notochord, muscle) in xenopus and into yolk-rich endodermal cells in newt (cynops pyrrhogaster). xenopus ectoderm consists of multiple layers, different from the single layer of cynops ectoderm. this multilayer structure of xenopus ectoderm may prevent complete treatment of activin a and subsequent whole differentiation into endoderm. in the present study, therefore, xenopus ... | 1999 | 10466926 |
| molecular cloning of newt sex pheromone precursor cdnas: evidence for the existence of species-specific forms of pheromones. | cloning of cdna encoding a decapeptide pheromone (sodefrin) that attracts conspecific female newts was attempted. a cdna clone encoding a protein consisting of 189 amino acid residues including a sodefrin sequence was isolated from a cynops pyrrhogaster abdominal gland cdna library. likewise, a cdna clone encoding a molecule comparable to the sodefrin precursor was obtained from a cynops ensicauda abdominal gland cdna library. this clone encoded a precursor protein of 192 amino acid residues, in ... | 1999 | 10471817 |
| expression of genes of type i and type ii collagen in the formation and development of the blastema of regenerating newt limb. | we cloned cdnas of alpha1(i) and alpha1(ii) collagen, and studied their expression profiles in regenerating limbs of newts, cynops pyrrhogaster. the expression of the alpha1(i) gene was markedly up-regulated at the early bud stage of the blastema. in situ hybridization experiments revealed that the alpha1(i) gene was expressed in not only mesenchymal cells of the blastema, but also the basal cells of the wound epidermis at the wound healing stage when the epidermal basement membrane was absent. ... | 1999 | 10474166 |
| immunohistochemical localisation of amelogenin-like proteins and type i collagen and histochemical demonstration of sulphated glycoconjugates in developing enameloid and enamel matrices of the larval urodele (triturus pyrrhogaster) teeth. | the presence of collagen in enameloid distinguishes it clearly from true enamel, but little is known about the phylogenetic relationship between these 2 tissues. it has previously been reported that amelogenins are the principal proteins of the enamel matrix, that type i collagen and chondroitin sulphates are the predominant matrices in dentine, and that amphibian and reptilian aprismatic enamels, contain no sulphated glycoconjugates, although certain sulphated substances are secreted into mamma ... | 1999 | 10580861 |
| production of a recombinant newt growth hormone and its application for the development of a radioimmunoassay. | complementary dna (cdna) encoding newt (cynops pyrrhogaster) growth hormone (ngh) was cloned from a cdna library constructed from mrnas of newt pituitary glands and was expressed in escherichia coli. based on northern blot analysis using the cdna as a probe, the ngh mrna was estimated to be 940 bases in length. the recombinant ngh (nghr) had a molecular mass of 22 kda as determined by sds-page and possessed considerable bioactivity as determined in a xenopus cartilage assay. using the nghr, we p ... | 2000 | 10620427 |
| expression of helix-loop-helix type negative regulators of differentiation during limb regeneration in urodeles and anurans. | the urodele is capable of regenerating its limb by forming a blastema even in the adult. by contrast, the anuran, which is phylogenetically close to the urodele, loses this ability during metamorphosis and forms blastema-like tissues that develop only into a spike-like structure in the adult. in order to compare the molecular mechanism of the formation and maintenance of the blastema between the urodele and anuran, the genes encoding helix-loop-helix (hlh) type negative regulators of differentia ... | 1999 | 10646803 |
| initiation of sperm motility in the newt, cynops pyrrhogaster, is induced by a heat-stable component of egg-jelly. | sperm motility in amphibians is thought to be initiated by a decrease in environmental osmolarity. however, fertilisation in the newt, cynops pyrrhogaster, is achieved in an environment without osmotic change. we show here that sperm motility initiating activity is present in jelly layer extract (je). je was gel-filtrated and a single peak with sperm motility initiating activity was detected in the fraction corresponding to about 50 kda. the activity was strengthened by heat treatment of je at 1 ... | 1999 | 10717951 |
| prolactin induces apoptosis in the penultimate spermatogonial stage of the testes in japanese red-bellied newt (cynops pyrrhogaster). | cell death is a common feature during spermatogenesis and, in some seasonal breeding animals, is often observed at the transition stage from spermatogonia to spermatocytes. in the japanese red-bellied newt, we have previously shown that this cell death is caused by the elevated titer of plasma prl that occurs after animals are transferred to low temperature, suggesting that cell death causes the cessation of spermatocytogenesis from late autumn to early spring. in the present report, first we sh ... | 2000 | 10830286 |
| distribution of dorsal-forming activity in precleavage embryos of the japanese newt, cynops pyrrhogaster: effects of deletion of vegetal cytoplasm, uv irradiation, and lithium treatment. | two types of axis-deficient embryos developed after deletion of the vegetal cytoplasm: wasp-shaped embryos and permanent-blastula-type embryos. in situ hybridization revealed that neither type of axis-deficient embryo expressed goosecoid or pax-6. brachyury was expressed in the constricted waist region of the wasp-shaped embryos but was not expressed in the permanent-blastula-type embryos. further, we examined the effect of uv irradiation on japanese newt embryos. surprisingly, uv-irradiated jap ... | 2000 | 10864468 |
| significance of egg-jelly substances in the internal fertilization of the newt, cynops pyrrhogaster. | japanese newt, cynops pyrrhogaster, undergoes internal fertilization as do most urodeles. in this study, we focused on the roles of egg-jelly in fertilization of c. pyrrhogaster and characterized the substances associated with those roles. when dry sperm were directly inseminated onto the egg, normal fertilization occurred without the presence of water. egg-jelly extract (je) prepared with steinberg's salt solution contained the activity for the initiation of sperm motility. a substance of about ... | 2000 | 10874160 |
| hormonal control of urodele reproductive behavior. | hormonal control of expression of courtship behavior and of development of structures related to the reproductive behavior in two species of japanese newts, cynops pyrrhogaster and cynops ensicauda, was described. prolactin (prl) and androgen were essential factors for eliciting courtship behavior. in addition, arginine vasotocin markedly enhanced the expression of courtship behavior. prl induced migration to water, in which courtship and oviposition take place, and converted the integument from ... | 2000 | 10874169 |
| hormonal influence on the olfactory response to a female-attracting pheromone, sodefrin, in the newt, cynops pyrrhogaster. | sodefrin is a female-attracting pheromone isolated from the abdominal glands of male newts, cynops pyrrhogaster. previously, the preference of conspecific female newts for sodefrin was shown to be completely abolished by plugging the bilateral nostrils, indicating that it acts on the olfactory organ. to determine the sensitivity of the olfactory receptor cells to sodefrin, electro-olfactograms (eogs) in response to sodefrin solution were recorded from the ventral nasal epithelium of sexually dev ... | 2000 | 10874171 |
| molecular cloning, functional characterization, and gene expression of a follicle-stimulating hormone receptor in the testis of newt cynops pyrrhogaster. | we previously demonstrated in vitro that mammalian follicle-stimulating hormone (fsh) stimulates the proliferation of newt secondary spermatogonia and their differentiation into primary spermatocytes. in the current study, we isolated a cdna from newt testis that encodes a fsh receptor (fsh-r). the total sequence homology in the deduced protein of the newt was approximately 70% with mammalian fsh-rs. mammalian cells, transiently transfected with the cloned newt fsh-r cdna, displayed specific bin ... | 2000 | 10944452 |
| identification and characterization of newt rad (ras associated with diabetes), a gene specifically expressed in regenerating limb muscle. | formation of the blastema is a key event for limb regeneration in urodele amphibians, and skeletal muscle has been thought to be a major origin of the multipotent blastemal mesenchyme. in the present study, we used differential display to identify the genes expressed differentially in the muscle at the amputation site. we have isolated a cdna clone that was upregulated during limb regeneration of the japanese newt, cynops pyrrhogaster. deduced amino acid sequence revealed that the cloned cdna wa ... | 2001 | 11146509 |
| newt prolactin and its involvement in reproduction. | the amino acid sequence of newt (cynops pyrrhogaster) prolactin deduced from the nucleotide sequence of its cdna showed a relatively high homology with sequences of chicken and sea turtle prolactins as well as with those of anuran prolactins. cynops prolactin receptor transcripts were detected in various tissues and organs, suggesting that prolactin plays multiple roles in urodeles. urodele prolactin was purified from the pituitaries of c. pyrrhogaster. antiserum against this prolactin was used ... | 2000 | 11149387 |
| injection of a sperm extract triggers egg activation in the newt cynops pyrrhogaster. | unfertilized eggs of the newt cynops pyrrhogaster are arrested at the second meiotic metaphase. the primary signal for egg activation is a transient increase in [ca2+](i), which is triggered by the fertilizing sperm and propagates over the egg cortex as a ca2+ wave. we injected an extract of cynops sperm (se) into unfertilized eggs and induced a wave-like [ca2+](i) increase which resulted in activation and resumption of meiosis. the se-injected eggs showed degradation of cyclin b1 and dna replic ... | 2001 | 11161564 |
| molecular cloning of newt prolactin (prl) cdna: effect of temperature on prl mrna expression. | a partial prolactin (prl) cdna was specifically pcr amplified from a cdna library constructed from pituitary mrnas of the newt (cynops pyrrhogaster) and cloned into plasmid vectors. one clone thus obtained contained a 739-bp insert encoding the c-terminal amino acid sequence of the mature hormone molecule. using this clone as a probe, the full-length newt prl cdna was screened from the cdna library. the prl cdna clone thus obtained consisted of 1024 bp encoding the entire sequence of the mature ... | 2001 | 11178884 |
| an experimental animal model of split cord malformation. | in this study, we examined an experimental animal model of split cord malformation (scm) produced by the surgical induction of a fistula. in cynopus pyrrhogaster neurulae (stage 18.5 +/- 0.5), the neural plate was incised and divided to construct a fistula that mimicked a neurenteric canal. after the procedure, the development of these embryos was examined morphologically and histologically. following incubation, hemicords, hemicords with their own heminotochords, and dermal sinus were observed ... | 2000 | 11182638 |
| cloning of dynein intermediate chain cdna of the newt cynops pyrrhogaster. | to isolate genes whose expression is up-regulated after initiation of meiosis, we employed an mrna differential display method using rna extracted from newt testis fragments in the spermatogonial and spermatocyte stages. we report here isolation of a spermatocyte stage-specific cdna clone encoding a newt homologue of dynein intermediate chain (ic). the newt dynein ic cdna was found to encode a polypeptide consisting of 694 amino acid residues with 66.8% and 45.8% amino acid sequence similarity t ... | 2001 | 11347905 |
| isolation of the third component of complement and its derivative with anaphylatoxin-like activity from the plasma of the newt cynops pyrrhogaster. | the third component of complement (c3) of a newt, cynops pyrrhogaster, was purified using a fast protein liquid chromatography technique. the purified newt c3 consists of two polypeptide chains (the molecular masses of the alpha and beta-chains of c3 were 120,000 and 70,000, respectively) linked by disulfide bonds. the alpha-chain retained an internal thiolester bond that was cleaved with methylamine, and the n-terminal amino acid sequence of the alpha-chain was xvqlidakagkaakf. digestion of new ... | 2005 | 11356226 |
| toxicity and toxin profiles of the newt, cynops pyrrhogaster from western japan. | a total of 382 specimens of a japanese newt, cynops pyrrhogaster, were collected from western japan during 1996 to 1999, and assayed for their individual, geographical, sexual, seasonal variations, and anatomical distribution of toxicity by mouse. most of the specimens tested showed toxicity scores ranging from 5 to 370 mu/g, where no seasonal, but large individual, sexual, and regional variations of toxicity were clearly recognized. among the parts, skin and muscle showed higher toxicity scores ... | 2001 | 11405279 |
| distribution of blue-sensitive photoreceptors in amphibian retinas. | previously, we reported that an opsin (rc-ms) belonging to the sws2 group opsins is expressed in bullfrog green rods [hisatomi, o. et al., febs lett., 1999, 447, 44-48]. an anti-rc-ms antiserum recognized the cones of the japanese common newt, cynops pyrrhogaster, which has no green rods. we isolated a cdna encoding an sws2 group opsin (cp-sws2) from this newt and found that cp-sws2 is expressed in a small population of the cones. our results suggest that sws2 opsins can be expressed in either g ... | 2001 | 11470275 |
| comparative study of sequential expression of the organizer-related genes in normal cynops pyrrhogaster embryos and mesodermalized ectoderm. | an artificially mesodermalized ectoderm (me) of early cynops pyrrhogaster gastrula acquires the organizer property; the me is able to induce the secondary axis. the expression of organizer-related genes was investigated during the mesodermalizing process of the me. the expression of c. pyrrhogaster organizer-related genes, such as bra, gsc, lim-1, chd and noggin, were analyzed. cynops pyrrhogaster shh expression was also investigated. the organizer-related genes were activated by 12 h after the ... | 2001 | 11473542 |
| cytopathologic observations of the lung of adult newts (cynops pyrrhogaster) on-board the space shuttle, columbia, during the second international microgravity laboratory experiments. | four adult female japanese newts, cynops pyrrhogaster, were carried for 15 days aboard the orbiting space shuttle, columbia, in july of 1994, as part of the second international microgravity laboratory, iml-2 aquatic animal experiments. these previously fertilized newts, after stimulation with chorionic gonadotropin by a spaceflight adapted injection procedure, deposited numerous eggs for study of early development during weightlessness. the primitive saccular lungs of the two newts which surviv ... | 1995 | 11536733 |
| formation of otoconia in the japanese red-bellied newt, cynops pyrrhogaster. | pre-mated adult female newts and fertilized eggs will be flown on the international microgravity laboratory-2 flight, in 1994. one objective of the flight will be to observe the influence of microgravity on the development of the gravity-sensing organs in the inner ear. these organs contain sensory hair cells covered by a layer of dense stones (otoconia). gravity and linear acceleration exert forces on these masses, leading to excitation of the nerve fibers innervating the hair cells. if the pro ... | 1994 | 11537935 |
| astronewt: early development of newt in space. | astronewt experiment explores the effects of earth gravity on the early development of japanese red-bellied newt, cynops pyrrhogaster. since female newts keep spermatophore in cloaca, fertilized eggs could be obtained without mating. fertilization of newt's egg occurs just prior to spawning, so that gonadotrophic cues applied to females in orbit leads to laying eggs fertilized just in space. a property of newt being kept in hibernation at low temperature may be of great help for the space exp ... | 1996 | 11538624 |
| development of gravity-sensing organs in altered gravity conditions: opposite conclusions from an amphibian and a molluscan preparation. | researchers examined early otolith development in microgravity using fertilized eggs of the japanese newt, cynops pyrrhogaster in space flight. ground experiments examined statocyst, embryonic statolith volume, and statoconia in the post-metamorphic marine mollusk aplysia californica reared at 1-g and 2-5.7-g. results indicate that exposure to hypergravity decreased the otolith mass to compensate for increased weight in aplysia. in the cynops, there was no compensatory difference in otolith mass ... | 1997 | 11540698 |
| expression of a novel matrix metalloproteinase gene during cynops early embryogenesis. | matrix metalloproteinases (mmps) are thought to play important roles in the gastrulation of cynops pyrrhogaster embryos. mmp cdnas were cloned from cynops pyrrhogaster and we report here a novel mmp called cymmp, which has strong similarity to mmp-21 (xmmp) in xenopus. reverse transcription-polymerase chain reaction (rt-pcr) analysis demonstrated that cymmp mrna was already present in cleavage stage embryos. the amount of the mrna then gradually decreased, but increased again starting in late ga ... | 2001 | 11606053 |
| secretory glands of tetrodotoxin in the skin of the japanese newt cynops pyrrhogaster. | intra-tissue distribution of tetrodotoxin (ttx) in the skin of larva, juvenile, and adult japanese newt cynops pyrrhogaster was investigated by means of a monoclonal antibody-based immunoenzymatic technique. in the investigation, ttx was localized at immature glands in juvenile, and at the granular cells composing of granular and mixed glands in adult specimens under a light microscope. no specific stain was recognized in larval section. a duct like structure extending from the granular gland to ... | 2002 | 11689234 |
| follicle-stimulating hormone is indispensable for the last spermatogonial mitosis preceding meiosis initiation in newts (cynops pyrrhogaster). | we previously reported that mammalian fsh induced differentiation of secondary spermatogonia into primary spermatocytes in organ culture of newt testicular fragments, whereas in medium lacking fsh primary spermatocytes never appeared. here, we investigated why spermatogonia fail to form primary spermatocytes in the absence of fsh. spermatogonia maintained proliferative activity and viability at about half the level of those cultured in the presence of fsh, progressed into the seventh generation, ... | 2002 | 11751258 |
| egg-jelly structure promotes efficiency of internal fertilization in the newt, cynops pyrrhogaster. | egg-jelly is composed of a network of fibrous components and contains substances regulating the sperm-egg interaction. many studies on the latter have been conducted, whereas the role of the egg-jelly structure in fertilization has not yet been fully assessed. in this study, we examined the fertilization efficiency in the presence and absence of the structure around the egg of the newt, cynops pyrrhogaster, using a gelatin gel system. although de-jellied eggs of c. pyrrhogaster can be fertilized ... | 2002 | 11857465 |
| regional specification of the head and trunk-tail organizers of a urodele (cynops pyrrhogaster) embryo is patterned during gastrulation. | the dorsal marginal zone (dmz) of an amphibian early gastrula is thought to consist of at least two distinct domains: the future head and trunk-tail organizers. we studied the mechanism by which the organizing activities of the lower half of the dmz (ldmz) of the urodelean (cynops pyrrhogaster) embryo are changed. the uninvoluted ldmz induces the notochord and then organizes the trunk-tail structures, whereas after cultivation in vitro or suramin treatment, the same ldmz loses the notochord-indu ... | 2002 | 11900459 |
| study of cynops pyrrhogaster notochord differentiation using a novel monoclonal antibody. | two monoclonal antibodies which reacted specifically with the notochord of the early cynops pyrrhogaster embryo were screened. the antigen molecules were detected within and around the notochord. they were first found mostly between the neural plate and the dorsal part of the notochord in the early neurula (stage 15). they were subsequently detected between the notochord and the somite in the advanced embryo, and they were last detected between the notochord and the underlying endoderm. whole-mo ... | 2002 | 11940099 |
| the activity for the induction of the sperm acrosome reaction localises in the outer layers and exists in the high-molecular-weight components of the egg-jelly of the newt, cynops pyrrhogaster. | localisation of the acrosome reaction inducing activity in egg-jelly was examined in the newt, cynops pyrrhogaster. the jelly has six layers: the j0, j1, j2, j3, j4 and st layers. jelly was mechanically dissected and placed on a millipore filter. when sperm were added from the outer surface side of the jelly, most of them exhibited the acrosome reaction after passing through the jelly. when egg-jelly was divided into four layers, strong activity for the induction of acrosome reaction was detecte ... | 2002 | 11964085 |
| sequence analysis and expressional regulation of messenger rnas encoding beta subunits of follicle-stimulating hormone and luteinizing hormone in the red-bellied newt, cynops pyrrhogaster. | two distinct cdnas encoding beta subunits of follicle-stimulating hormone (fsh) and luteinizing hormone (lh) were cloned from the cdna library constructed for the pituitary of the red-bellied newt, cynops pyrrhogaster, and sequenced. the newt fshbeta and lhbeta cdnas encode polypeptides of 129 and 131 amino acids, including signal peptides of 20 and 19 amino acids, respectively. the number and position of cysteine and n-glycosylation in each of the beta subunits of fsh and lh, which are consider ... | 2002 | 11967191 |
| peptide and protein pheromones in amphibians. | purification, characterization and biological activity of urodele and anuran sex-pheromones were reviewed. female-attracting pheromones obtained from the abdominal gland of cynops pyrrhogaster and c. ensicauda males are peptides consisting of 10 amino acid residues being designated sodefrin and silefrin, respectively. each pheromone attracted only conspecific females. molecular cloning of cdnas encoding sodefrin and silefrin revealed that both are generated from precursor proteins. synthesis of ... | 2002 | 11997210 |