bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sex and Region‐Specific Regulation of Oestrogen Receptor β in the Rat Hypothalamus
Authors: Orikasa C. , Sakuma Y. 
Published: January 2005

AbstractSexual dimorphism in the expression of oestrogen receptor (ER)β mRNA and protein was characterized in the rostral forebrain of the rat and its dependence on the neonatal endocrine environment was revealed. We present novel data demonstrating, in gonadectomized adult rats, that the amount of oestrogen caused a significant reduction in the number of ERβ messages and protein in the ventromedial nucleus in both sexes, but no such effects were detected in the preoptic area or the amygdala. In gonadectomized females, more so than in males, the ventromedial nucleus of the adult rat contained a significantly larger number of ERβ‐positive neurones both in terms of ERβ mRNA and protein. In the juvenile rat on day 14, sex difference in ERβ expression was already observed in the ventromedial nucleus. Treatment of neonatal females with oestrogen from days 1–10 or neonatal orchidectomy of males reversed the sex difference in the ventromedial nucleus when observed on day 14, showing that the neonatal presence of oestrogen had caused irreversible masculinization of this structure. Our results suggest that sex‐specific expression of ERβ is patterned by perinatal hormone exposure: down‐regulation of ERβ caused by oestrogen in a region‐specific manner.
Fos Expression is Selectively and Differentially Regulated By Endogenous Glucocorticoids in the Paraventricular Nucleus of the Hypothalamus and the Dentate Gyrus
Authors: Fevurly R. D. , Spencer R. L. 
Published: January 2005

AbstractWe examined the extent to which basal levels of corticosterone, which vary in a circadian fashion, influence the pattern of Fos protein expression in the paraventricular nucleus of the hypothalamus (PVN), the hippocampal formation and three different functional cortical areas. Basal and poststress (1 h of restraint) Fos expression, as determined by immunohistochemistry, was examined in male rats with either no previous surgical manipulation or in rats 5 days after: (i) sham adrenalectomy; (ii) adrenalectomy with no corticosterone replacement; or (iii) adrenalectomy with corticosterone (25 µg/ml) in the drinking water replacement. In adrenal‐intact rats, restraint produced similar patterns of Fos expression in the PVN, cortical areas and hippocampus (CA1–CA3), with peak levels of expression attained 60–90 min after restraint onset. Surprisingly, in the dentate gyrus, there was a dissociation between the two blades in the pattern of Fos expression after restraint. In the inner blade (suprapyramidal), there was a delayed induction that occurred between 60 and 90 min after restraint onset and, in the outer blade (infrapyramidal), there was a steady decline in Fos expression after restraint. Adrenalectomy had an effect on Fos expression only in the PVN and dentate gyrus, and the nature of the effect was quite different for both brain regions. In the PVN, adrenalectomy had no effect on Fos expression in unstressed rats, but resulted in an enhanced number of Fos positive cells after restraint. In the dentate gyrus, adrenalectomy resulted in an overall reduction of Fos positive cells in both blades, and this reduction was present in unstressed and stressed rats. Corticosterone replacement normalized the adrenalectomy effect on Fos expression in both brain regions. Thus, Fos expression in the rat brain displays specific patterns of dependency on the permissive effects of glucorticoids, and this dependency varies between brain regions.
LOCALIZATION AND MULTIPLE FORMS OF ACETYLCHOLINESTERASE IN SEA URCHIN EMBRYOS
Authors: OZAKI HIRONOBU 
Published: January 2005

Acetylcholinesterase during the development of the sea urchin Pseudocentrotus depressus was examined by enzyme assay (the colorimetric method of Ellmanet al.), histochemistry (a Cu‐thiocholine method), polyacrylamide gel electrophoresis and DEAE‐Sephadex ion exchange chromatography.The enzyme activity is detected in the unfertilized egg, remains low during cleavage, elevates slightly through gastrulation, and then increases rapidly thereafter. The intense activity is localized in the mesenchyme cells associated with the larval skeleton of young pluteus larvae, and their cell membranes and nuclear envelops. Soluble enzyme accounts for 60% of the total activity. The additional 34% is extracted by 1% Triton X‐100 from particulates. The soluble enzyme consists of two forms. Both are strongly acidic proteins which are similar in electric charge, but dissimilar in size, being 180,000 and 280,000 in molecular weights. The enzyme released from the membrane by the detergent possesses a component which is not present in the soluble complement of the enzyme. It is not a secondary product of the soluble enzyme interacting with the detergent.Acetylcholinesterase serves as a marker of late differentiation and regional differentiation in the sea urchin embryo.
STUDY OF THE NUCLEI ISOLATED FROM NEWT EMBRYOS BY THE USE OF FICOLL
Authors: TAKAHASHI YOSHIHIRO , ASAO TEZRO 
Published: January 2005

1) Nuclei were isolated from early newt embryos using Ficoll in the isolation medium. Nuclei thus isolated were almost free from cytoplasmic contamination, with minimum loss of the nuclear constituents. The characterization of the nuclei thus isolated, including the determination of RNA polymerase activity and analysis of population of RNA's synthesized, is described.
2) In addition, the nuclei isolated from blastulae were characterized by electron microscopic observation, by the determination of RNA polymerase activity and by analysis of the chromatin constituents.
DIFFERENTIATION OF PARTIALLY MESODERMALIZED ECTODERM; HOMOIOGENETIC AND HETEROGENETIC INDUCTION BY PRIMARILY INDUCED PART OF THE ECTODERM
Authors: NISHIJIMA KATSUSHI , NODA SHINICHI , KURIHARA KAZUSHIGE , SASAKI NAOI 
Published: January 2005

Using embryos of the Japanese newt, Cynops pyrrhogaster, homoiogenetic and heterogenetic induction were investigated in the partially mesodermaelzed presumptive ectoderm. Half of the isolated presumptive ectoderm was placed in contact with the swimbladder of the crucian carp, Carasius auratus, for 15 or 60 min, while the other half was stained with Nile blue sulfate at the same time. The distribution of the stained cells in the tissues evoked in the explants was examined after cultivation for 10 days.Some mesodermal tissues were composed of both stained and unstained cells. This indicates homoiogenetic induction by the primarily induced part of the ectoderm on the other half. The neural and epidermal tissues in the explants were composed of stained cells only, except in one case. We conclude that the neural tissues are derived from cells not placed in contact with the swimbladder and that they are induced by the primarily induced part of the ectoderm.
A DETAILED FATE MAP OF THE WING DISC OF SARCOPHAGA PEREGRINA
Authors: AKIYAMA YOSHINORI , OHTAKI TETSUYA 
Published: January 2005

In order to construct an anlageplan of the imaginal disc, various fragments of the wing disc from mature larvae of Sarcophaga peregrina were implanted into host larvae of the same age. The implants were metamorphosed with the host and the differentiated adult structures were analyzed.On the basis of the results obtained from the transplanted disc fragments, a fate map of the wing disc was satisfactorily constructed.The fate map of S. peregrina is similar to an earlier study of Drosophila, but the PAA, PWP, and AP are located in different positions from those of Drosophila.
VEGETALIZATION OF PRESUMPTIVE ECTODERM OF NEWT GASTRULAE IN A TRANSFILTER EXPERIMENT WITH FISH SWIMBLADDER AS THE INDUCTOR
Authors: KAWAKAMI IZUMI , SASAKI NAOI , SATO ATSUKO , OSAKO NOBUMITSU 
Published: January 2005

The diffusibility of the vegetalizing factor was examined by a transfilter culture using an ethanol‐fixed swimbladder of the crucian carp (Carassius auratus) as the inductor and presumptive ectoderm from gastrulae of Cynops pyrrhogaster as the responding tissue. Nucleopore filters, about 12–14 μm thick, with nominal pore sizes of 0.05, 0.1, 0.6, 0.8, 3.0 and 8.0 μm were interposed between the interacting tissues. The responding pieces of ectoderm were removed from the assemblies after contact for 0.5, 1, 3, or 24 hr and cultured in Holtfreter's solution for 10 days at 20°C.The inductions observed were almost entirely mesodermal, although masses of endoderm‐like yolky cells were seen in explants and neural tissues in a few cases. Filter membranes with pores of 0.05 to 8.0 μm did not interfere with the vegetalizing effect.Under an electron microscope, small cytoplasmic cones of the responding cells of the presumptive ectoderm were observed in the pores of the interposed filter after 3 hr's contact. The cones grew longer as the cultivation time increased, but even after 24 hr there was no contact between the interacting tissues. Since 3 hr's contact between the interacting tissues was sufficient to cause full vegetalization on the transfilter culture with the swimbladder, the formation of the cytoplasmic outgrowths had no significance in the induction.
A Normal Table of Early Development in Bombina Orientalis (Boulenger), in Relation to Rearing Temperature
Authors: MICHAEL PREMA 
Published: January 2005

The effect of temperature on the rate of development of Bombina orientalis has been investigated. Eggs obtained by hormonal stimulation were reared at 9 to 22.5°C with a variation of ±0.5°C, and development was followed up to the neurula stage.Between 20 and 22.5°C development proceeded normally with very little variation in time. Large time deviations were evident at temperatures below 18°C, particularly after the commencement of gastrulation. Abnormalities occurred at low temperatures and were common at 9°C. At 7°C initial cleavage was incomplete and further development did not occur.
Chick Embryo Extract, Muscle Trophic Factor and Chick and Horse Sera as Environments for Chick Myogenic Cell Growth
Authors: HAGIWARA YASUKO , KIMURA ICHIRO , OZAWA EIJIRO 
Published: January 2005

Chick myogenic cells grew in a medium composed of Eagle's minimum essential medium (MEM), horse serum (HS), and one of the essential factors needed for myogenic cell growth (EFMG), that is, chick embryo extract (EE), chick serum (CS), or the muscle trophic factor (MTF). But they did not grow in the absence of the EFMG. In the absence of HS, they scarcely grew in a medium composed of MEM, and EE or MTF. They grew in a medium composed of MEM and CS; they grew much better in a medium composed of MEM, CS, and HS.In the presence of one of the EFMG, the optimal HS concentration for growth varied depending on its lot. At higher HS concentrations, growth was suppressed. Further, it was suggested that an inhibitory substance(s) for myogenic cell growth was present in HS. The inhibitory effects can usually be minimized by diluting the serum with an artificial medium.
Early Events in Anuran Amphibian Fertilization: An Ultrastructural Study of Changes Occurring in the Course of Monospermic Fertilization and Artificial Activation
Authors: CHARBONNEAU M. , PICHERAL B. 
Published: January 2005

In unfertilized frog eggs, the plasma membrane displays an animal vegetal polarity characterized by the presence of short microvilli in the vegetal hemisphere and long microvilli or ridge‐like protrusions in the animal hemisphere. The densities of microvilli are similar in the two hemispheres.The fertilizing sperm always fuses with the animal hemisphere of the egg and induces a wave of exocytosis of cortical granules from its site of penetration. Similar spreading of the cortical reaction is seen on activation by pricking the egg cortex. The integration of the cortical granule membrane with the plasma membrane is rapidly followed by elongation of microvilli, which is progressively realized all over the egg surface from the site of sperm entry or the site of pricking. At this time, the length and shape of the microvilli in the animal and vegetal hemispheres are similar and their densities are the same as in unfertilized eggs.A “smoothing” wave can be seen on the living egg, 40–60 seconds after pricking, starting around the site of pricking. This wave of microvillar elongation is accompanied by changes in intensity of diffracted light spots observed at the surface of the egg. This pattern might result from rapid and progressive thickening of the cortex that would drive pigment granules into the cytoplasm. The Brownian movement of these granules is thought to be responsible for the observed diffracted light spots.Electrical stimulus or the ionophore A23187 induced activation reactions similar to those triggered by the sperm or by pricking, except that the cortical reaction began simultaneously in several distinct sites of the cortex.
Effects of UV‐irradiation at Various Wavelengths on Sterilizing Drosophila Embryos
Authors: TOGASHI SHIN , OKADA MASUKICHI 
Published: January 2005

Embryos of Drosophila melanogaster at the early intravitelline nuclear multiplication stage were irradiated with UV light at the posterior pole. The sterility and mortality of these embryos were examined in relation to the dose and wavelength of the UV light.Sterility, expressed either as the frequency of pole‐cell‐deficient embryos, or as the frequency of agametic adults, was found to be dependent on the wavelength of UV light. UV‐irradiation at 280 nm was found moot effective in causing sterility on Drosophila embryos. The minimum dose of radiation to give a 100% sterility was 200 J/m2 at 280 nm, and 400 J/m2 at 254 nm. In contrast, mortality showed no dependency on the wavelength.The possibility that nucleic acids in the posterior region is a target of 280 nm radiation is discussed.
Spermiogenesis in the Flatworm, Notoplana Japonica with Special Attention to the Organization of an Acrosome and Flagella
Authors: KUBO‐IRIE MIYOKO , ISHIKAWA MASARU 
Published: January 2005

Ultrastructural changes during spermiogenesis in the flatworm, Notoplana japonica were studied with special attention to organizing process of an acrosome and flagella. During spermiogenesis, the Golgi complex develops conspicuously but it fails to organize the structure of an acrosomal vesicle. Consequently, no acrosome is formed at the apex of the sperm. As a substitute for an acrosomal structure, the slender process at the tip of the mature sperm is prominently occupied with glycogen granules.The axoneme of the flagellum is formed from the basal body in the protrusion which is juxtaposed to the nucleus of the early spermatid. Two flagella associated with an electron‐dense structure (EDS) extend superficially from the spermatid body in opposite directions. Progressively, they take an acute angle to each other and finally run alongside the sperm body. The axoneme consits of nine peripheral doublets with arms, a central cylinder containing an electron dense core, a less dense intermediate zone and fine spokes between the cylinder and doublets.
Induction of the Acrosome Reaction of Sea Urchin Spermatozoa by Means of Urea
Authors: KATO KOICHI H. , SUGIYAMA MASAO 
Published: January 2005

Urea is an effective reagent for inducing the acrosome reaction of spermatozoa in sea urchins. Urea‐treated spermatozoa are capable of fertilizing eggs in Ca‐deficient sea water. The pH of the urea solution is an important factor affecting the induction of the acrosome reaction. The reaction occurs at a high percentage in urea Solution at pH's higher than 7.8, while the reaction is almost completely suppressed at pH 7.2. Ca++ is also an important factor for the induction of the reaction, although the minimum concentration required is very low.The acrosomal filament formed in urea solution is similar in shape to that formed in egg‐water, when fixed after 10 seconds' urea‐treatment. The acrosome granule material is found around the basal portion of the acrosomal filament.
Neuroendocrine Regulation of the Development of Seasonal Forms of the Asian Comma Butterfly, Polygonia c‐aureum L
Authors: ENDO KATSUHIKO 
Published: January 2005

In the butterfly, Polygonia c‐aureum, development of seasonal forms controlled by the photoperiod and temperature was shown to involve a neuroendocrine system of the brain‐corpus cardiacum‐corpus allatum complex.For analysis of the neuroendocrine system concerned, the innervation of the complex was investigated first by cobalt chloride perfusion staining and then by severance of axons, ablation of the candidate cells, injection of a homogenate of these cells and transplantation of corpora cardiaca using pupae programmed to be either summer‐form or autumn‐form adults.The results suggested that medial nerve cells produce what is called material producing the summer form.The seasonal forms of the Asian comma butterfly, Polygonia c‐aureum L., summer and autumn forms (Fig. la, b), are determined by the photoperiod and the temperature during the larval period (1–3). Previous studies have given the following results on the physiological mechanism involved in the effect of environmental factors in inducing these seasonal forms. First, the mechanism involves neurosecretory cells located somewhere in the brain (2). Second, the nervous connections between the brain and the corpus cardiacum (NCC I+II (4)) and between the right and left brain lobes are indispensable for the effect (2, 5–7).The present study consisted of two series of experiments. One was designed to demonstrate morphologically the axonal connection of the corpus cardiacum with the corpus allatum in this butterfly, like that shown in several other insects (8–13). The other series was designed to locate the neurosecretory cells producing material related to the seasonal form and to see if this material is also present in the corpus cardiacum.
Mode of Action of some Stimulants of the Hatching Enzyme Secretion in Fish Embryos*
Authors: IUCHI ICHIRO , HAMAZAKI TATSUO , YAMAGAMI KENJIRO 
Published: January 2005

Mode of action of two stimulants of the hatching enzyme secretion, electric current (AC) and potassium cyanide, was analyzed by applying them to Medaka embryos in the presence or absence of suppressants of nervous system‐mediated secretion, tetrodotoxin or MS–222. Electric current (AC) stimulated the secretion of the hatching gland of the embryos that had been treated with these suppressants, while potassium cyanide did not. These results strongly suggest that electric current acts as a stimulant of hatching enzyme secretion directly on the gland cell itself, while potassium cyanide stimulates the secretion indirectly, probably through nervous system of the embryo.In the present experiments, it was also shown that Ca2+ and ionophore, X‐537A, when applied directly to the hatching gland extracellularly, induced a marked secretion‐associated morphological change of the gland cells instantaneously. However, it was found that chum salmon prolactin did not induce the secretion‐associated morphological changes in the hatching gland cells when it was applied directly to the gland cells in situ or indirectly through embryonic circulation.
Partial Purification from Chick Embryos of a Factor which Promotes Myoblast Proliferation and Delays Fusion
Authors: ICHIO  , OZAWA EIJIRO 
Published: January 2005

Chick embryo extract (EE) contained an activity which promoted myoblast proliferation and delayed fusion. Various tissue extracts prepared from 12‐day embryos and adult chicken also showed the activity. We partially purified this active substance from 12‐day embryos, following procedures which included extraction at pH 3.5, CM‐Sephadex C–50 ion exchange and Sephadex G‐75 gel filtration. Judging from the dose‐response analyses, the factor was purified by some hundred‐fold when EE was used as the starting material. The activity was associated with a macro‐molecular substance (MW > 300K daltons) at first, but the apparent molecular weight of the active substance was estimated to be between 16 and 20K daltons at the final step of the preparation. It promoted myoblast proliferation and delayed myotube formation, and was active for both avian and rat myoblasts.Since bovine pituitary gland fibroblast growth factor (FGF) showed the same activity, the factor may be FGF‐related.
Comparative Study on the Ability of Various Teratocarcinomas to Form Chimeric Mouse Embryos
Authors: HANAOKA KAZUNORI , KATO YOSHIHIRO , NOGUCHI TAKEHIKO 
Published: January 2005

Various embryonal carcinoma cells of different origins were compared as to the ability to form chimeric blastocysts by means of aggregating with normal 8‐cell stage mouse embryos. The teratocarcinoma lines examined were OTT6050 and five newly established ones including a spontaneous testicular teratocarcinoma STT‐2. The present results have revealed that distinct differences existed in the ability of colonizing blastocysts among teratocarcinomas and also among embryonal carcinoma cell lines.Since STT‐2 stem cells were found to be incorporated into blastocysts most efficiently, further development of the blastocysts were examined in utero. It was found that STT‐2 stem cells could be incorporated into the fetuses up to the 7‐to 28‐somite stages. This is the first case to demonstrate that testicular teratocarcinoma cells with the male germ cell origin have the developmental potency to participate into mouse embryogenesis.
Microtubules During Blastoderm Formation in the Egg of the Silkworm, Bombyx mori L.
Authors: TAKESUE SACHIKO , KEINO HIROOMI 
Published: January 2005

Microtubules in the silkworm egg, Bombyx mori, were observed by electron microscopy, in order to investigate the relationship between cytoskeletal organelles and the migration of energids, the cleavage nuclei accompanied by the associated cytoplasm, near the egg surface or during blastoderm formation. Numerous microtubules were observed in the associated cytoplasm of an energid even in the interphase of mitosis.At about 8.5 hr after oviposition, when many energids had already cleft and distributed near the peripheral yolk granule region, long microtubules distributed radially from the perinuclear region to the periphery in the associated cytoplasm. When an energid was protruding, the microtubules above the nucleus distributed at a more acute angle than those under the nucleus. When a blastoderm cell had just been formed, the microtubules were observed only under the nucleus.Colchicine, an inhibitor of microtubules, stopped the migration of energids and inhibited the formation of blastoderm cells even after many energids had already distributed at the peripheral yolk granule region. The relationship between the microtubules and the migration of energids near the egg surface or during blastoderm formation was discussed.
Pattern Regulation of the Leg Disc of the Fleshfly, Sarcophaga peregeina
Authors: KAMAI HIROYUKI , OHTAKI TETSUYA 
Published: January 2005

A fate map of the hind leg disc of Sarcophaga peregrina was constructed by examining the adult structures of implanted disc fragments. The locations of presumptive adult structures in the disc were similar to those of fore leg disc of Drosophila and Sarcophaga ruficornis. However, the concentric borderlines of the segments could not be ascertained in the present case.Pattern regulation of disc fragments was studied by culturing them either in adult females for several days or for 3 days in mature larvae placed on wet condition. Cultured disc fragments regenerated or duplicated as in Drosophila, with some exceptions. For instance, the region with a high density of positional values, the upper medial quarter, of the fore leg disc of Drosophila was not found. A characteristic difference in the rate of regeneration or duplication was observed in the implanted fragments, when cultured in larvae or adult hosts. This variable pattern regulation in larval and adult hosts could be due to different compositions of the hemolymph in which would healing of the implanted disc fragments takes place.