bluuebunny/crossref_metadata_2025 huggingface dataset:
EFFECTS OF TEMPERATURE ON THE PATTERN OF RNA SYNTHESIS IN XENOPUS LAEVIS NEURULA CELLS
Authors: NISHIO Y. , SHIOKAWA K. , YAMANA K.
Published: January 2005

Isolated cells of Xenopus laevis neurulae were labeled with 3H‐uridine at three different temperatures (21°C, 30°C and 10°C), and the pattern of RNA synthesis was examined, using polyacrylamide gels. At 21°C (standard temperature), the synthesis of 28S and 18S ribosomal RNA (rRNA), as well as other RNAs, occurred quite actively. At 30°C (higher temperature), the syntheses of rRNA, 4S and heterogeneous RNA were all increased about twofold (Q10= 2). When the temperature was lowered to 10°C, however, the accumulation of both 28S and 18S rRNA was inhibited nearly completely, while the other RNAs were still synthesized at a 50% level. The absence of 40S rRNA precursor at 10°C makes it highly likely that at the lowered temperature the transcription of rRNA precursor is inhibited. These effects of temperature changes on RNA synthesis were all reversible: the synthesis returned to a normal rate within 4 hr in those cells that had previously been exposed to the lower or higher temperature for 6 hr.
CARDIAC MUSCLE CELL DIFFERENTIATION IN VITRO FROM A CHARACTERISTIC CELL LINE ISOLATED FROM MOUSE TERATOCARCINOMA
Authors: AMANO SHIGETOYO , UNO KAZUKO , HAGIWARA ATSUYOSHI
Published: January 2005

A characteristic in vitro cell line, SEBIII, was isolated from the mouse teratocarcinoma OTT6050. The SEBIII line, which maintains the structure of the embryoid body, grows rapidly in suspension culture. The chromosome number is near diploid. SEBIII cells, which were transferred to the peritoneal cavity of 129/Sv strain mice and left for one week, differentiated into several tissues in the subsequent in vitro culture. Of the tissues differentiated, the most dominant was the spontaneously pulsating muscle cells. Electron microscopic observations of these muscle cells revealed the presence of myofilaments with Z bands and intercalated disks. The nature of the factor(s) which induce the differentiation of SEBIII EB into cardiac muscle cells is discussed.
MOUSE MUSCLE CELL DIFFERENTIATION IN CLONAL CULTURE
Authors: NAKAMURA HARUKAZU , FUJISAWA HAJIME , WATANABE KENJI , KUBO SEIICHI , IBATA YASUHIKO
Published: January 2005

Clonal culture of muscle cells from thigh muscles of the term fetus of the mouse was undertaken. Myoblasts were spherical or spindle‐shaped, and proliferated exponentially until day 4 in culture. The generation time of the muscle cells from 2 to 4 days' culture was 9.1 to 13.4 hr. The fusion of myoblasts began on day 4 in culture; many myotubes had been formed by day 6 and spontaneous contraction was observed on day 7. Clonal efficiency was 30%, and the proportion of muscle colonies in all the colonies was 72%.
DOES COLCHICINE AFFECT AGGREGATION OF NORMAL AND TRANSFORMED BHK CELLS DIFFERENTLY?
Authors: OZAKI HIROKI S. , OKADA T. S. , YASUDA KUNIO
Published: January 2005

The effect of colchicine and vinblastine on cell aggregation was studied, using BHK cells and their transformed derivatives (pyBHK cells). When cells were dissociated with EDTA and the assay was made in a Ca2+‐containing medium, the aggregation of transformed cells was prevented by colchicine and vinblastine, whereas the aggregation of normal cells was unaffected. When a Ca2+‐free medium was used for aggregation, neither type of cell was influenced by these drugs. BHK and pyBHK cells, dissociated by trypsin in the presence of Ca2+, can aggregate only in the Ca2+‐containing medium and the aggregation of both cell types was equally prevented by colchicine and vinblastine. Based on these results, it was concluded that colchicine and vinblastine inhibited the Ca2+‐dependent mechanism of cell adhesion, but not the Ca2+‐independent one which occurs in the Ca2+‐free aggregation medium.
EFFECTS OF THYROXINE AND PROLACTIN ON COLLAGEN BREAKDOWN IN THE THIGH BONE AND TAIL FIN OF THE RANA CATESBEIANA TADPOLE
Authors: YAMAGUCHI KEIICHIRO , YASUMASU IKUO
Published: January 2005

Injection of 14C‐proline into the tadpole causes labeling of protein in the collagen fraction of the thigh bone and tail fin. The radioactivity of the 14C‐hydroxyproline residue is about 26% of the total radioactivity in the 14C‐labeled protein of the collagen fraction in the thigh bone as well as in the tail fin. In 14C‐proline‐loaded tadpoles into which prolactin has been injected, the radioactivity in the collagen fraction in these tissues is markedly higher than that in control animals. In thyroxine‐treated tadpoles, the 14C‐radioactivity of the collagen fraction in the thigh bone is always higher than that of the controls, but it is markedly low in the tail fin. During the incubation of thigh bone and tail fin isolated from 14C‐proline‐loaded tadpoles, low molecular weight materials containing 14C‐hydroxyproline are released from the 14C‐labeled protein of these tissues. The rate of 14C‐hydroxyproline release, which represents the rate of collagen breakdown, is higher in thigh bone and tail fin isolated from thyroxine‐treated tadpoles and is markedly lower in these tissues isolated from prolactin‐treated tadpoles than in those isolated from controls. In these tissues, the high rate of collagen breakdown in thyroxine‐treated tadpoles is reduced by prolactin injection.
STABILITY OF ISOLATED MITOTIC APPARATUS DURING STORAGE*
Authors: FORER ARTHUR , ZIMMERMAN A. M.
Published: January 2005

Mitotic apparatus (MA) were isolated from sea urchin zygotes using various isolation procedures, and various properties of the isolated MA were studied and compared. MA isolated using hexylene glycol had birefringences which depended on the pH of the isolation medium, the lower the pH the higher the MA birefringence. The stability of the MA Birefringence also depended on the pH of the hexylene glycol isolation medium (the lower the pH the slower the rate of decay of birefringence), as did the final birefringence reached after prolonged storage. MA isolated using glycerol‐dimethylsulphoxide (MTME) had much more stable birefringence than MA isolated using hexylene glycol; their birefringence decay rates were about 1000 times slower than those of MA isolated using hexylene glycol.

Birefringence which remained after extraction of MA with H2O, or 0.5 M KC1 was also studied; the results depended on the MA isolation medium, on the medium the MA were stored in, and on the amount of time the MA were stored after isolation, as described in detail in the text.

These results are discussed, and it is suggested that several components (including, perhaps, oriented ribosomes) contribute to birefringence of isolated MA.
DEVELOPMENT OF THE SEA‐STAR, ASTERINA BATHERI GOTO
Authors: KANO YASUO T. , KOMATSU MIÉKO
Published: January 2005

Using natural spawning and artificial fertilization, the entire process of development from eggs to juveniles was observed in the sea‐star, Asterina batheri Goto.

The breeding season of this animal in Tsukumo Bay and Toyama Bay is estimated to be late summer. The spawned eggs are approximately 430 μm in diameter and float near the surface of sea water. They develop, through a wrinkled blastula stage by holoblastic. radial cleavage, into a pear‐shaped brachiolaria bearing 3 blunt brachiolar arms. Metamorphosis takes place while the brachiolariae are swimming. Ten days after fertilization, metamorphosis is complete; the resulting juveniles are about 800 μm in diameter and colored pale brown with a green tint. They bear 2 pairs of tube‐feet and a terminal tentacle in each arm.

Development of this species is thus of the direct type, and very similar in every respect to that of Asterina coronata japonica, which is closely related to the present species.
ENZYMES OF THE TRICARBOXYLIC ACID CYCLE IN SEA URCHIN EGGS AND EMBRYOS
Authors: OKABAYASHI KEN , NAKANO EIZO
Published: January 2005

Changes in the activity of some enzymes of the tricarboxylic acid cycle during development of sea urchins were investigated. Unfertilized eggs showed substantial activity of citrate synthase, aconitase, NAD‐ and NADP‐specific isocitrate dehydrogenases, fumarase and malate dehydrogenase. During development, the activity of citrate synthase, aconitase, NADP‐specific isocitrate dehydrogenase and malate dehydrogenase increases gradually, whereas the activity of fumarase remains rather constant. There is no close correlation between changes in the enzyme activity and the increase in oxygen consumption during development. Citrate synthase, aconitase, NADP‐specific isocitrate dehydrogenase are mainly localized in the mitochondrial fraction, whereas fumarase and malate dehydrogenase are present in both mitochondrial and cytosol fractions. The intracellular localization of these enzymes does not change during development. A possible mechanism for the regulation of some enzymes of the tricarboxylic acid cycle in sea urchin eggs is discussed.
CHANGES IN ACTIVITIES OF CREATINE KINASE, ARGININE KINASE AND THEIR MULTIENZYME FORMS DURING EMBRYONIC AND LARVAL DEVELOPMENT OF SEA URCHINS
Authors: FUJIMAKI HIDEKAZU , YANAGISAWA TOMIO
Published: January 2005

The presence and the changes of CPK and APK have been studied during larval development through metamorphosing of Hemicentrotus pulcherrimus, Anthocidaris crassispina and Pseudo‐centrotus depressus. While no CPK activity was found in the unfertilized eggs and the embryos of early developmental stages, APK was quite active throughout these stages. At the late 8‐armed pluteus stage just prior to metamorphosis, CPK first became active. Electrophoretically this CPK was identical with one of three CPK forms of sperm, tube feet and esophagus but not with two CPK forms of lantern muscle. APK in the unfertilized eggs and early embryos was electrophoretically separated into two distinct molecular forms, one of which disappeared during the late larval stages. The persisting form of larval APK was identical with a single APK form present in the adult muscular tissues.
ENZYMO‐CYTOCHEMICAL OBSERVATIONS ON THE CORTICAL CHANGE IN THE EGGS OF CYPRINUS CARPIO AND CARASSIUS AURATUS
Authors: KUDO SHIGEHARU
Published: January 2005

Acid phosphatase (AcPase) and cholinesterase (ChE) activities were examined by ultracytochemical techniques in the mature unfertilized and the fertilized eggs of Cyprinus carpio and Carassitus auratus, to reveal the differences among three kinds of structures, cortical alveoli, CA‐ and CB‐granules, which discharge their contents on fertilization into the perivitelline space. Deposits of the reaction product for AcPase activity are localized on the plasmalemma of unfertilized eggs, in the cortical alveoli, cytoplasmic matrix, lamellae of the Golgi apparatus and sometimes in multivesicular bodies but not in CA‐ and CB‐granules, mitochondria, rough endoplasmic reticulum or on the plasmalemma of fertilized eggs. Deposits of the reaction product for ChE activity are localized on the inner surface of the plasmalemma, in the cytoplasmic matrix, in mitochondria and on a small number of tubular or cisternal membranes of the endoplasmic reticulum in mature unfertilized eggs, and on the outer surface of the limiting membrane of CB‐granules and on membranous structures (possibly Golgi lamellae) associated with their formation, in fertilized eggs. The deposits on the plasmalemma rapidly disappear almost completely, with discharge of the cortical alveoli soon after fertilization, but they are again seen on the inner surface of the plasmalemma when emiocytotic discharge of the CB‐granules begins about 10 min after fertilization.
VACUOLATION OF EXPLANTED AND IMPLANTED NOTOCHORDS OF AMPHIBIA
Authors: TAKAYA HIROSI , KAYAHARA TETSURO
Published: January 2005

Processes of vacuolation were investigated with the explanted and implanted rudiments of amphibian notochord. Explanted notochords generally underwent vacuolation when they were surrounded by other differentiating tissues. In the absence of these tissues, they were not only unable to vacuolate but also unable to survive. When the notochords were implanted into the ventral mass of yolk granules of neurula, they showed no vacuolation and died within a few days if they were alone and not surrounded by other differentiating tissues. These facts suggest that the presence of other differentiating tissues surrounding the notochord is a requisite for the notochord to vacuolate. Further, the fact that in explanted notochords, vacuolation was frequently interrupted and was left unfinished when the surrounding tissues were scarce, suggests that the quantity of the surrounding tissues is important in promoting vacuolation. Interruption of the vacuolation occurs in the explanted notochord at any stage from the beginning to the end of the process. Therefore, almost all the stages of vacuolation were observed in these notochords. Very frequently, different parts of a single notochord presented different stages of vacuolation. All these stages were essentially the same as those found in the normal notochord. From these results, it emerges that although vacuolation of the explanted and implanted notochords is carried out with the same process as in the normal intact one, it is accomplished only when they are surrounded by a sufficient quantity of other differentiating tissues.
INDIVIDUAL VARIATION IN THE DISTRIBUTION OF LENS POTENCY IN WOLFFIAN LENS REGENERATION
Authors: WATANABE KENJI
Published: January 2005

After lentectomy in newts, lens regeneration originates from the iris. The regenerant was externally observed with a stereomicroscope as a depigmented area (DA) of the iris, and the extent of DA up to 15 days after lentectomy was measured. The extent of DA was found to differ among individuals, whereas it was the same in both eyes of each animal. In a number of animals one eye was used for lentectomy. After measuring the DA, two groups of animals were selected; a “W‐group” with an extremely wide DA that deviated from the standard value, and “N‐group”, with an extremely narrow DA. Six iris sectors obtained from the animals of the W‐group or N‐group were implanted into lentectomized eyes of other animals to investigate the difference in the distribution of lens potency in these two groups. Animals of the W‐group possessed a wider distribution of lens potency than animals of the N‐group. Pulse‐labelling with 3H‐thymidine on lentectomized eyes of both groups was done 0, 3, 5, 7 and 12 days after lentectomy. DNA‐synthesis began earlier and continued longer in the dorsal part of the iris of the W‐group than in that of the N‐group. The distribution of lens potency in the iris is discussed on the basis of these findings.
MORPHOLOGICAL CHANGES OF CULTURED MYOCARDIAL CELLS DUE TO CHANGE IN EXTRACELLULAR CALCIUM ION CONCENTRATION
Authors: GOSHIMA KIYOTA , YAMANAKA HACHIRO , EGUCHI GORO , YOSHINO SHIGEO
Published: January 2005

Increase in the extracellular Ca2+ concentration from low (≤ 10−7 M) to normal (10−3 M) caused morphological changes of cultured myocardial cells obtained from fetal mouse heart. The extracellular Na+ and K+ concentrations of the normal medium (10−3 M Ca2+) did not significantly affect the genesis of these morphological changes. Like Ca2+, Ba2+ and Sr2+, but not Mg2+, Co2+ or Ni2+, could induce morphological changes. Increase in the extracellular Ca2+ concentration from 10−8 M to 10−3M also caused excess uptake of 45Ca2+ by cultured myocardial cells. B–16CW 1 cells, which did not show these morphological changes, did not take up excess 45Ca2+ on this treatment. Treatments, such as addition of verapamil or incubation at pH 6.3, which reduced the genesis of morphological changes, reduced the rate of 45Ca2+ uptake by myocardial cells. These facts show that the morphological changes of myocardial cells induced by increasing the extracellular Ca2+ concentration from low to normal are due to excess uptake of Ca2+ by the myocardial cells.

The morphological changes of cultured myocardial cells induced by increasing the extracellular Ca2+ concentration from low to normal were reversed on further incubation of the cells in medium with or without Ca2+.
Electron Microscopic Analysis of Phagocytic Activity of Chick Embryonic Retinal pigment cells in vitro
Authors: TSUNEMATSU YASUHIKO , FUNAHASHI MASAKAZU , NAKAJIMA AKIRA
Published: January 2005

The phagocytosis of latex particles by retinal pigmented cells from chick embryos was studied in vitro. The pigment epithelial cells phagocytized latex particles within 2 hr without a latent period, as found in some mamalian species. The number of latex phagosomes increased with time, and the phagosomes eventually became distributed nearly uniformly in the cytoplasm. When cultures that had been exposed to latex particles for 24 hr were incubated without the particles for a further 7 days, numerous latex phagosomes remained inside the cells without any decrease in their number. This indicates that phagocytized particles are not ejected from the cells, presumably due to a defect in, or absence of, exocytotic activity.
An Ultrastructural Study of Cell‐to‐Cell Membrane Interaction at Early Stages of Postnatal Ontogenesis of Cortical Brain Neurons in White Rats
Authors: GLEZER I. ILYA
Published: January 2005

In early postnatal ontogenesis of cerebral cortex (visual area) of the white rat, a wide distribution of different types of membrane contacts have been found between developing nervous cells and their processes. The following types of contacts were observed: 1. Penetration of thin filopodia into specialized invaginations having all the features of coated vesicles; 2. Contacts of filopodia with thickened surface membrane; 3. Contacts of opposit filopodia; 4. Contacts of membranes with reciprocal invaginations alternating with filopodia or surface blebs.

These types of membrane interaction were regularly distributed along the surface of cells and their processes, and were situated in close approximation to typical tight junctions and other adhesional complexes. As a rule, filopodia were components of axon branches, and almost all invaginations were situated on plasma membranes of cell bodies or on dendrites, although sometimes there were invaginations on axon profiles and filopodia on dendrites.

It is suggested that the distribution and structural specialization of these membrane contacts reflect their participation in the process of programmed cell‐to‐cell recognition that precedes the formation of synaptic contact. Other reports and the current data reveal the special morphogenetic role of membrane communication in the formation and stability of integrative cell systems.
The Persistence in the Synthesis of Type H Proteoglycan and Type II Collagen by Chondrocytes Cultured in the Presence of Chick Embryo Extract1
Authors: KATAGIRI YOHKO U. , YAMAGATA TATSUYA
Published: January 2005

The effect of chick embryo extract on the phenotypic expression of differentiated chondrocytes has been studied in consideration of the fact that these cells are well characterized by certain specific cell products, such as type H proteochondroitin sulfate and type II collagen. In this study, we utilized floating chondrocytes derived from chick embryonic sterna, which can be cultured in suspension with no apparent change in the type of cell products for at least a period of eight weeks, as described in a previous paper (1). In the presence of chick embryo extract in the medium, the floating chondrocytes became attached to the bottom of the culture dish, and the attached cells took on a fibroblast‐like appearance. Biochemical analyses of the proteochondroitin sulfate and collagen synthesized by the attached cells revealed that if the culture medium was renewed everyday, the cells having a fibroblast‐like appearance continued to synthesize type H proteochondroitin sulfate and type II collagen. When however, the medium was replaced every other day, the synthesis of both proteochondroitin sulfate and collagen by the attached cells switched from the chondrocyte type to the fibroblast type, i.e. the synthesis of type M proteochondroitin sulfate and type I collagen, with little change in the fibroblast‐like appearance. The results show that the morphological features of chondrocytes are not necessarily associated with the biochemical properties of these cells, and further suggest that, in chick embryo extract, there is no modulator capable of acting directly on the chondrocytes to bring about phenotypic changes with respect to the synthesis of collagen and proteoglycans.
Change in Hatching Enzyme Activity during Development of the Sea Urchin, Hemicentrotus Pulcherrimus
Authors: NAKATSUKA MITSUNOBU
Published: January 2005

The time course of change in hatching enzyme activity during development of embryos of the sea urchin Hemicentrotus pulcherrimus was observed. The enzyme was present in the particulate fraction in embryos until the time of hatching and was maximal at the time of hatching. Cell fractionation studies suggested the existence of an inhibitor of the hatching enzyme. This possibility was subsequently substantiated by experiments in mixtures of fractions: the activity of hatching enzyme in the particulate fraction was inhibited by the supernatant of embryos. This inhibitory factor was heat‐stable and non‐dialyzable, but it was not characterized further. The activity of secreted hatching enzyme was not inhibited by this factor, suggesting that the molecular forms of hatching enzyme in embryos and in the culture supernatant are different. After hatching, the amount of increase in the hatching enzyme activity in the culture supernatant was 3.5 times the amount of decrease in enzyme activity in the embryos, suggesting that the enzyme was activated during its secretion.
Chromatin Arrangement and Axis Formation in the Spermiogenesis of a Pulmonate Snail
Authors: TERAKADO KIYOSHI
Published: January 2005

Nuclear change in relation to axis formation and condensation during spermiogenesis was investigated in the snail, Physa acuta. In the early spermatid, characteristic thick layers (termed apical and basal plates) are formed on two sides of a nuclear envelope. Soon after the formation of these plates, a developing acrosome and a flagellum attach externally to the center of the apical and basal plates, respectively. However, most (presumably all) of the chromatin filaments become attached all over the inner surface of the apical and basal plates. This means that the plates themselves are actually the specialized forms of the nuclear envelope to which chromatin filaments become connected; by means of these plates, the chromatin filaments become arranged in parallel to the antero‐posterior axis as the nucleus elongates. This suggests that the formation of these two thick layers on opposing surfaces of the nucleus primarily determines the antero‐posterior axis of the spermatid and the direction of the arrangement of chromatin.

The flattening of the nucleus prior to elongation is caused mainly by the enlargement of the basal plate. Subsequent nuclear shaping and condensation are discussed in relation to the change in the surface structures of the nucleus and the organization of the microtubules.
Light and Electron Microscopic Studies on Fertilization of Pelmatohydra Robusta I. Sperm Entry to a Specialized Region of the Egg
Authors: NODA KOICHI , KANAI CHIEKO
Published: January 2005

Fertilization of a fresh water polyp, Pelmatohydra robusta, was studied by light and electron microscopy. A small depression was observed in the animal pole of the unfertilized egg. The egg pronucleus was always situated in close contact with the bottom of the depression. Microvilli which were covered with an egg coat consisting of filamentous components were observed on the egg surface. Microvilli and the egg coat were not detected on the surface of the depression. Sperm were associated with the egg plasma membrane and entered the egg only at the bottom of the depression. Excess sperm aggregated around the depression of inseminated eggs. After fertilization, the egg made a protrusion in the region where the egg pronucleus and sperm were in close contact with each other. A new egg coat was formed on the entire surface of the fertilized egg. The restriction of sperm‐egg interactions to a specialized region of the hydra egg is discussed in connection with the micropyle of Pisces eggs and the animal dimple of Discoglossus (Anura) eggs.
The Role of Extracellular Ca2+ in the Activation of Pectinaria Oocytes
Authors: ANSTROM JOHN , SUMMERS ROBERT G.
Published: January 2005

Several events are associated with fertilization in oocytes. Two such events are an increase in cytoplasmic Ca2+ concentration and the resumption of meiosis. Oocytes of the marine annelid, Pectinaria gouldii, are in metaphase I arrest when they are spawned. In this report we investigate the relationship between Ca2+ and resumption of meiosis in this species. Meiosis in unfertilized oocytes could be re‐initiated with the divalent cation ionophore, A23187. Oocytes in Ca2+ free sea water, however, did not resume meiosis in the presence of the ionophore. Furthermore, it was observed that Ca2+ must be present for at least 15 min following ionophore treatment for meiosis to resume. These results suggest that extracellular Ca2+ is required for the re‐initiation of meiosis in this species.
Cytoplasmic Maturity Revealed by the Structural Changes in Incorporated Spermatozoon during the Course of Starfish Oocyte Maturation
Authors: HIRAI SETSURO , NAGAHAMA YOSHITAKA , KISHIMOTO TAKEO , KANATANI HARUO
Published: January 2005

Immature oocytes of the starfish, Asterina pectinifera, are polyspermic. Spermatozoa can enter immature oocytes upon insemination, but the changes associated with the fertilization process in oocytes matured with 1‐methyladenine (1‐MeAde), such as the formation of aster and pronucleus, were not observed. After immature oocytes, previously inseminated, were matured with 1‐MeAde, the formation of the sperm monaster was observed during germinal vesicle breakdown (GVBD). Amphiasters and pronuclei were formed after the formation of the second polar body. The acquisition by oocytes of the capacity to undergo the normal process of fertilization, therefore, occurs during the course of oocyte maturation. After injection of the cytoplasm of maturing oocytes into inseminated immature oocytes, the formation of aster and pronucleus was observed, suggesting that maturation‐promoting factor (MPF) may be involved in establishing the cytoplasmic conditions (cytoplasmic maturity) necessary for the fertilization process to occur. In contrast, when enucleated, inseminated halves of immature oocytes were treated with 1‐MeAde, only monasters were formed, while in the nucleated halves both amphiasters and sperm pronuclei were formed. Thus, germinal vesicle material is required for the formation of amphiaster and sperm pronucleus but not for the formation of monaster. It is possible that the amount of MPF produced in enucleated halves was sufficient only for the formation of the monaster but not for the formation of the amphiaster and pronucleus, since it has been previously established that germinal vesicle material is necessary for the amplification of MPF. The formation of the monaster in the enucleated halves at a time corresponding to GVBD in nucleated controls suggests that the amount of MPF needed for this event is rather small. For the induction of subsequent fertilization process, large amounts of MPF may be required to establish the necessary cytoplasmic conditions, although other possible role of nuclear material is not excluded.
Oviducal Contribution to Alteration of the Vitelline Coat in the Frog, Rana japonica. An Electron Microscopic Study
Authors: YOSHIZAKI N. , KATAGIRI CH.
Published: January 2005

The vitelline coat (VC) surrounding coelomic eggs of the frog, Rana japonica, comprises bundles of filaments running both parallel and perpendicular to the egg surface. The coat gives little or no staining reaction with PA‐CrA‐Silver methenamine. In contrast, in the VC of uterine eggs the filament bundles are less conspicuous. and the interstices between the filament bundles stain strongly for carbohydrate. This alteration occurs during passage of the eggs down the first 1/20 th of the oviduct, the pars recta. The epithelium of the p. recta contains secretory cells, which contain electron‐dense granules distinct from those in the jelly‐secreting cells in more caudal portions of the oviduct. Treatment of coelomic eggs with an extract of p. recta followed by exposure to a sperm suspension resulted in marked swelling and softening of the VC. These results indicate that the contents of the granules secreted from the epithelial cells in the p. recta are deposited in the VC to increase its susceptibility to a fertilizing sperm.
Characterization of the Constituent Fatty Acids in the Phosphoglycerides of Chemically Induced Polycystic Disease and Gastric Tumor in Rat
Authors: RYUZAKI MASASHI , OHTA AKISHIGE , OSHIMA MIEKO
Published: January 2005

The positional distribution of fatty acids in choline‐ and ethanolamine phosphoglycerides from the livers of polycystic disease‐bearing rats and stomachs of gastric tumor‐bearing rats was analyzed and compared to that in normal rat liver and stomach. Polycystic disease and gastric tumors were induced with N‐Methyl‐N′‐Nitro‐N‐Nitrosoguanidine. There was no significant difference between diseased and normal organs with respect to the composition of fatty acids at the 1‐position, except that diseased livers exhibited an increase of approximately 22% in 16: 0 fatty acid and a decrease of approximately 12% in 18: 1 fatty acid. However, in diseased organs, there were marked quantitative changes in the positional distribution of fatty acids at the 2‐position, their composition exhibiting greater saturation. Furthermore, in diseased organs, there was an increase in 15: 0 fatty acid at the 2‐position of ethanolamine phosphoglycerides.
Glycoproteins from Teratocarcinomas and Organs of Adult Mice: Analysis by Affinity Chromatography on Lectin‐conjugated Agarose1
Authors: OZAWA MASAYUKI , FUJIYAMA JIRO , FURUKAWA TATSUHIKO , SATO KUMIKO , NOGUCHI TAKEHIKO , MURAMATSU TAKASHI
Published: January 2005

Glycoproteins were isolated from particulate fraction of four teratccarcinomas and several organs of adult mice by affinity chromatography on lectins conjugated with agarose [concanavalin A (Con A), wheat germ agglutinin (WGA), Ricinus communis agglutinin (RCA), peanut agglutinin (PNA) and Dolichos biflorus agglutinin (DBA)] and were compared by SDS gel electrophoresis. Glycoprotein components were found to be very similar in three lines of solid teratocarcinoma, namely F9, STT‐2 and OTT‐10A. Teratocarcinoma OTT6050, which is an ascitic form called embryoid bodies, also gave glycoprotein profiles somewhat similar to those of other teratocarcinomas. However, glycoprotein profiles of most adult organs were significantly different from those of teratocarcinomas. The following points were of special interest. 1) RCA receptors from the four teratocarcinomas gave a strong band with an apparent molecular weight 145,000 daltons, which was either weak or absent in the receptors from adult organs. 2) The WGA receptors of all adult organs except muscle and small intestine gave more intense bands than those of the teratocarcinomas. 3) Glycoproteins with molecular weights of more than 240,000 daltons were present in WGA receptors, RCA receptors and PNA receptors of teratocarcinoma OTT 6050, but not in the receptors of other teratocarcinomas.
Differentiation of Various Cell Types during Fruiting Body Formation of Dictyostelium Discoideum*
Authors: HAYASHI MORIAKI , TAKEUCHI IKUO
Published: January 2005

The processes of differentiation of the presumptive cells (prespore and prestalk cens) into mature spores, stalk and basal‐disc cells in Dictyotelium discoideum was investigated. The number of stalk and disc cells in pre‐labeled culminating cell masses was estimated by determining the radioactivity of the undissociable fraction separated by filtration from the dissociable fraction containing presumptive cells and spores. Changes in the proportion of amoeboid cells stainable with fluorescein‐conjugated antispore serum and encapsulated spores were also followed in the dissociable fraction.

Formation of stalk and disc cells began at 17 hr of development and was completed at 26 hr, while formation of morphologically identifiable spores began at 18 hr and was completed at 20 hr, long before completion of stalk formation. At the onset of culmination, unstained cells abruptly increased with an accompanying decrease of stained cells, when unstained rear‐guard cells appeared in the hind region. Although some of the rear‐guard cells soon differentiated into basal‐disc cells, the rest remained amoeboid in the upper part of the spore mass (sorus) after complete formation of a fruiting body. Despite the presence of the amoeboid cells in mature sori, the proportion of the sorus to the stalk and disc of a fruiting body was approximately equal to that of stained (prespore) to unstained (prestalk) cells in a migrating slug.
Change in the Respiratory Rate of Sea Urchin Spermatozoa following Sperm‐egg Interaction in the Absence of Mg2+
Authors: FUJIWARA AKIKO , YASUMASU IKUO , MOHRI HIDEO
Published: January 2005

Spermatozoa of the sea urchin, Hemicentrotus pulcherrimus (108 cells/ml), preincubated with unfertilized eggs deprived of jelly coats (more than l05 cells/ml) at 20°C for 20min in Mg2+ free artificial sea water containing 1 mM Ca2+ (MFASW), exhibited very low respiration, which was enhanced by 2, 4 dinitrophenol (DNP). The fertilization rate in MFASW was usually less than 5% and was about 25% at most. Preincubation with fertilized eggs (with and without a fertilization membrane) in MFASW did not reduced the respiratory rate of spermatozoa. The rate of sperm respiration was lower in MFASW than in artificial sea water (ASW), but was higher than the respiratory rate of spermatozoa preincubated in MFASW with unfertilized eggs. Sperm respiration in MFASW or in ASW was not stimulated by 2, 4 dinitrophenol. Almost complete inhibition of sperm respiration was obtained with unfertilized eggs fixed with glutaraldehyde at concentrations of above 105 cells/ml in MFASW and of about l04 cells/ml in ASW. The respiratory rate of spermatozoa treated with fixed eggs was enhanced by DNP. It is concluded that the respiratory rate of the spermatozoa is reduced by their interaction with unfertilized eggs before their penetration into the eggs.
Morphological Characterization of First Instar Larvae of Asian Horseshoe Crabs and their Hybrids*
Authors: YAMAMICHI YOSHIO , SUGITA HIROAKI , SEKIGUCHI KOICHI
Published: January 2005

The morphological characters of first instar larvae of three Asian horseshoe crabs and their hybrids were examined. For this purpose, the length of six parts on the larvae, the pattern of pigmentation, the structure of the margin of the opisthosoma, and the distribution and shape of spines on the extracardiac region of the prosoma were recorded. In general, the phenotypes of the hybrids were intermediate between those of the parents, suggesting that both male and female genomes contribute to development of the hybrids. However, there were some exceptional characters and phenotypic variations. Some characters were inherited from only one parent. This was suggested to imply that if the maternal species did not have the gene regulating expression of a given paternal character, the paternal gene did not express this character.
Changes in Activities of Glucose Metabolising Enzymes in Germ Cells during Spermatogenesis in Rats
Authors: NAKAMURA MASAHISA , FUJIWARA AKIKO , YASUMASU IKUO , OKINAGA SHOICHI , ARAI KIYOSHI
Published: January 2005

The rate of 14CO2, liberation from [14C‐1]glucose was identical to that from [14C‐6]glucose in spermatids, but more than the latter in spermatogonia. Rotenone (1 μM) completely inhibited 14CO2 release from [14C‐1]glucose in spermatids, but decreased it only 30% in spermatogonia. The activity of glucose‐6‐phosphate dehydrogenase, but not 6‐phosphogluconate dehydrogenase, was markedly lower in spermatocytes and spermatids than in spermatogonia. The activities of the glycolytic enzymes, glucosephosphate isomerase, fructose diphosphatase, glyceraldehyde‐3‐phosphate dehydrogenase and enolase, differed only slightly in spermatids and spermatogonia. It is concluded that the low glucose‐6‐phosphate dehydrogenase activity may contribute to the low activity of the pentose cycle in spermatocytes and spermatids.
Changes in Soybean Agglutinin (SBA) and Peanut Agglutinin (PNA) Binding Pattern in the Epidermis of the Developing Chick Embryo
Authors: TAKATA KUNIAKI , HIRANO HIROSHI
Published: January 2005

Lectin binding pattern in the developing chick embryonic epidermis was studied using peroxidase labeling method. The epidermis of the 13‐day‐old embryo is in an undifferentiated state. Little binding of soybean agglutinin (SBA), specific for N‐acetyl‐D‐galactosamine, and peanut agglutinin (PNA), specific for β‐D‐galactose, was seen in such epidermal cells. As the epidermis developed toward keratinization, the cell membrane of the differentiating flattened cells was positively stained with SBA and PNA. The positive staining was also seen in the supranuclear region of the cells located between the flattened cells and the basal cells. The basal cells remained unstained in all the stages of development. Similar staining pattern with SBA and PNA was seen in the cultured skin explants during the epidermal differentiation in vitro. These observations show that the SBA‐ and PNA‐reactive glycoconjugates accumulate during the epidermal cell differentiation, suggesting their important roles in the maintenance of the ordered structure of the epidermis.
Sperm Bind but Do not Unbind from the Fixed Sea Urchin Egg
Authors: GREEN JEFFREY D.
Published: January 2005

In S. purpuratus sperm remained bound to aldehyde‐fixed eggs and did not exhibit a detachment phase. Sperm bound in high numbers and the binding curve was similar to that for unfixed homologous gametes. Binding kinetics were analyzed using sequential still photographs of slightly flattened, fixed eggs under supported coverslips. In this way, a single egg could be observed. Alternatively, sperm remaining in the supernatant over settled eggs were counted at successive time points postmixing using spectrophotometry (340 nm) and hemocytometry. Additionally, aliquots of mixed gametes were fixed at successive time points and the numbers of bound sperm determined microscopically on egg perimeters. The maximum number of sperm bound by 2 min; this number remained at or near maximum for as long as 10 min when the experiments were terminated. When sperm were jelly‐reacted before addition to eggs, fewer sperm bound, although binding curves were similar to the above experiments. It appears that the binding efficiency of sperm decreases with time after initiation of the acrosome reaction: (1) fewer prereacted sperm bound; and, (2) sperm did not continue to bind after 2 min even though the egg surface was not saturated. Whether these effects are related to motility or other factors is unclear. Furthermore, the above results indicate the importance of the cortical reaction to sperm unbinding. Such studies enable one to observe sperm behavior while precluding the effects of egg secretion during the initial stages of fertilization.
Progression throughout All Stages of Meiosis from the Early Prophase of Newt Primary Spermatocytes in vitro
Authors: NISHIKAWA AKIO , SHIN‐ICHI ABE
Published: January 2005

Stages of prophase of living primary spermatocytes were determined by use of Rose culture chambers (1). Dissociated primary spermatocytes were cultured at low cell‐density in a collagen matrix at 22°C or 27°C and the percentages of cells which had progressed from various stages in prophase through meiosis to various advanced stages were measured. In a standard medium (Leibovitz‐15 + 10% fetal bovine serum), more than 70% of the primary spermatocytes at stages beyond the pachytene stage could advance to round spermatids with flagella within a few days at 22°C. The percentages of cells that progressed from stages before the late zygotene stage were less, but at least 13 % of leptotene cells reached metaphase I within a week at 22°C. The percentage of cells that progressed was slightly lower at 27°C than at 22°C: 6.3 and 4.3 days were required for progress from leptotene to metaphase I at 22°C and 27C, respectively. Fetal bovine serum was not indispensable for progression through meiosis. Moreover, 0.5–5.0 μg/ml ovine follicle stimulating hormone (NIAMDD‐o‐FSH‐13), 0.01–1.0 μg/ml 5α‐dihydrotestosterone and 1.0 μg/ml testosterone propionate had no significant effect in increasing the percentage of cell progression at 22°C.
Ultrastructural Evidence that Chick Primordial Germ Cells Leave the Blood‐Vascular System Prior to Migrating to the Gonadal Anlagen
Authors: ANDO YUKO , FUJIMOTO TOYOAKI
Published: January 2005

It is known that chick primordial germ cells (PGCs), after separation from the endoderm in early embryonic development, temporarily circulate via the blood‐vascular system and eventually migrate to the gonadal anlagen. However, direct evidence that circulating PGCs leave the blood vessels is lacking. The purpose of present study is to describe the ultrastructural features of PGCs as they emerge from the blood vessels. PGCs leaving the blood vessels were first examined with semi‐thin sections stained with toluidine blue. Then, some of the sections were re‐embedded in Epon 812, and sectioned for electron microscopy. PGCs were observed emerging from the capillaries in the region posterior to the omphalomesenteric arteries of the embryo, between the splanchnic mesoderm and open‐gut endoderm, at stages 15–18 (about 2.5 days of incubation). Ultrastructurally, PGCs exhibited the protruding, bulge‐like cytoplasmic processes through the endothelial gaps in the capillary walls. Prior to emerging, intravascular PGCs seemed to stick to the endothelium of the blood vessels. Thus, our results offer ultrastructural evidence that the circulating PGCs exit the blood vessels prior to migrating to the gonadal anlagen.
Pathogenesis of Thalidomide Teratogenesis in the Marmoset (Callithrix jacchus): Evidence Suggesting a Possible Trophic Influence of Cholinergic Nerves in Limb Morphogenesis
Authors: McBRIDE W. G. , VARDY P. H.
Published: January 2005

Thalidomide administered to the marmoset (Callithrix jacchus) will produce a pattern of deformities similar to those found in man. In the cervical and lumbar regions of the thalidomide malformed marmoset fetus, the spinal cord and dorsal root ganglia are smaller than those of the control. The reduction in size of the D.R.G.'s is due to a marked reduction in the number of neurons. Drugs which influence the function of cholinergic nerves in the chick and rabbit embryo interfere with development. Thalidomide produced peripheral neuropathy in adults by interference with the function of the cholinergic nerves. Thus it appears that thalidomide malformations are due in part, to an interference with numbers of, and probably the functions of, the cholinergic nerves in the embryo. It would appear that cholinergic nerves have a possible morphogenetic and trophic influence in embryogenesis.
The Inhibitory Effect of 5‐Bromodeoxyuridine on the Programmed Cell Death in the Chick Limb
Authors: TONÉ SHIGENOBU , TANAKA SHOJI , KATO YOSHIHIRO
Published: January 2005

The inhibitory effect of 5‐bromodeoxyuridine (BrdU) on the programmed cell death in interdigital mesenchyme of a chick leg bud was studied using vital staining and histological methods. A single administration of BrdU at day 6 1/3 specifically inhibited the programmed cell death in the mesenchyme of interdigital areas of a leg bud, resulting in the formation of a web‐like structure. No inhibitory effect was observed on general development of limb buds. Hoechst 33258 staining revealed that many cells of interdigits incorporated BrdU into their nuclei. The simultaneous administration of thymidine blocked the BrdU effect.
Cloning and Characterization of Genes Expressed in the Mouse Reticulocytes
Authors: MISHINA YUJI , NATORI SHUNJI , OBINATA MASUO
Published: January 2005

In mouse reticulocytes, approximately 250 middle abundant‐rare class messages were estimated to be present besides globin mRNA (OBINATA and IKAWA, 1980). Approximately 200 independent genomic clones (rt‐clones) expressed in the mouse reticulocyte mRNAs were obtained from a mouse gene library. Surprisingly, most of the rt‐clones are shown to be expressed even in non‐erythroid tissues significantly. By the plaque hybridization method with 133 rt‐clones, the pattern of expression of these genes was examined at different stages of erythroid cell maturation.
In Vitro Regression of Tadpole Tail by Thyroid Hormone
Authors: NIKI KAORU , YOSHIZATO KATSUTOSHI , NAMIKI HIDEO , KIKUYAMA SAKAÈ
Published: January 2005

DERBY successfully maintained the tail of tadpole (Rana pipiens) in vitro over a period of 2 weeks in a physiological salt solution (1). When we tried to apply DERBY'S methods of the tissue culture to tadpoles of bullfrog, Rana catesbeiana, it was found that the tissue regressed spontanously without stimulation of thyroid hormone. Several different media were examined in order to select a better culture medium for the bullfrog tadpole tissues. RPMI‐1640 medium supplemented with insulin and transferrin was found to be satisfactory for this aim. With this improved medium, the interaction between the epidermis and the mesenchyme has been investigated during the hormone‐induced tadpole tail regression and the epidermal dependence of the mesenchyme regression was demonstrated by the following three experiments. (i) Some of surgically prepared mesenchymes regressed in responce to thyroid hormone. In these cases the mesenchymes were revealed to be contaminated with the remaining epidermal cells. (ii) Complete removal of the epidermis was accomplished by the chemical treatment. The mesenchyme thus obtained (“nude tail fin”) was insensible to thyroid hormone. (iii) “Skin conditioned medium” (SCM) was prepared by culturing the skin in the presence and absence of thyroid hormone. Nude tail fin regressed when cultured in the SCM containing thyroid hormone.
Isolation and Purification of Vitelline‐Coat Lysin from Testis of Turbo cornutus (Mollusca)
Authors: OGAWA ATSUKO , HAINO‐FUKUSHIMA KAZU
Published: January 2005

A substance causing swelling of the vitelline coat (vitelline‐coat lysin) was extracted from the testis of a sea snail, Turbo cornutus. Its activity was quantified by a volumetric method using a suspension of vitelline coat isolated from T. cornutus eggs. The lysin was purified 50‐fold by hydroxyapatite and Bio‐Gel P‐10 column chromatographies and the final preparation appeared homogenous on sodium dodecyl sulfate polyacrylamide gel electrophoresis. Its molecular weight was estimated to be 18,500 by sodium dodecyl sulfate polyacrylamide gel electrophoresis, and 18,000 by sedimentation equilibrium analysis. These results suggested that the lysin exists as a monomeric molecule. Its isoelectric point was pH 6.4. The lysin contained residues of most common amino acids except cystine and cysteine, with relatively high proportions of lysine, aspartic acid and leucine. The N‐terminal amino acid was identified as serine. The lysin loosened the fibrous structure of the vitelline coat without releasing any soluble product and seemed to act by a stoichiometric, nonenzymatic mechanism.