bluuebunny/crossref_metadata_2025_split huggingface dataset:
Parthenogenetic development of bovine oocytes treated with ethanol and cytochalasin b after in vitro maturation
Authors: Fukui Yutaka , Sawai Ken , Furudate Makoto , Sato Noriyuki , Iwazumi Yasuaki , Ohsaki Kazue 
Published: February 2005

AbstractThe present study was conducted to investigate the effects of different culture durations (24–36 hr) on bovine oocyte maturation in vitro and the effect of the presence or absence of cumulus cells at the time of treatment to induce parthenogenetic activation (exposure to ethanol and cytochalasin B; CB) (experiment I). The effects of dosage (2.5 or 5.0 μg/ml) and incubation time (2.5, 5, or 10 hr) in CB (experiment II) on the subsequent development to the blastocyst stage in vitro was also investigated. In experiment I, cleavage and development to the blastocyst stage were not affected by the presence or absence of cumulus cells at the time of parthenogenetic activation. However, the 24‐hr culture duration for in vitro maturation had a significantly lower rate of development to the blastocyst stage than the longer culture durations (27‐36 hr). In experiment II, treatment with 5 μg/ml CB for 5 hr showed the highest percentage of development to blastocyst in the oocytes matured for both 27 and 30 hr. To determine the viability of the parthenogenetic embryos (morulae and blastocysts), four recipient heifers received two embryos each, and one heifer was found to be pregnant on day 35 following transfer. Although fetal heartbeat was not observed, the subsequent estrus was prolonged in all heifers. The present results demonstrate development of in vitro‐matured, parthenogenetically activated bovine embryos up to the preimplantation stage. © 1992 Wiley‐Liss, Inc.
Stage‐Specific expression of rat transition protein 2 mrna and possible localization to the chromatoid body of step 7 spermatids by in situ hybridization using a nonradioactive riboprobe
Authors: Saunders P. T. K. , Millar M. R. , Maguire S. M. , Sharpe R. M. 
Published: February 2005

AbstractThe present study has used methoxyacetic acid (MAA)‐induced depletion of specific germ cell types in the rat and in situ hybridization with nonradioactive riboprobes to determine the stages of the spermatogenic cycle at which there is expression of the mRNA for the basic chromosomal protein transition protein 2 (TP2). On Northern blots, an abundant mRNA was detectable in samples from control adult rats, but the amount of message was markedly reduced when RNA was extracted from the testes of rats treated 14 and 21 days previously with methoxyacetic acid. These testes were depleted specifically of step 7–12 spermatids, suggesting that these cells contain TP2 mRNA. When tissue sections were subjected to in situ hybridization, the TP2 mRNA was localized at the cellular and subcellular levels. Messenger RNA for TP2 was first detectable in spermatids at step 7. In these spermatids, at high magnification, in addition to some positive reaction in the cytoplasm, intense staining was located to a perinuclear structure consistent with localization of mRNA within the chromatoid body. The amount of TP2 mRNA in the cytoplasm increased as remodelling of the early spermatid nucleus progressed and was highest in step 10 and 11 spermatids at stages X and XI. Thereafter, the mRNA decreased until it was undetectable in step 14 spermatids at stage XIV. The localization of TP2 mRNA to the chromatoid body of step 7 spermatids would be consistent with this organelle being a storage site for long‐lived mRNAs utilized later in spermiogenesis. © 1992 Wiley‐Liss, Inc.
The third IGF‐II promoter specifies transcription of three transcripts out of five in human placenta
Authors: Daimon Makoto , Johnson Thomas R. , Ilan Joseph , Ilan Judith 
Published: February 2005

AbstractInsulin‐like growth factor‐II (IGF‐II) mRNA exists as multiple transcript size classes, such as 6.0, 5.3, 4.9, 3.2, and 2.2 kb mRNAs in various human tissues. Three different promoters, 2 different polyadenylation sites, and alternative splicing are involved in producing these multiple transcripts. Initiation of transcription at the 3 different promoters results in multiple mRNAs which contain identical coding regions but different 5′‐untranslated regions (5′‐UTRs). The first promoter is thought to direct expression of 5.3 kb mRNA in adult human liver. The second promoter region directs expression of 6.0, 3.2, and 2.2 kb mRNAs in human fetal tissues and several adult nonliver tissues. The third promoter specifies transcription of a 4.9 kb mRNA in various tissues. We isolated and sequenced a cDNA clone (pIGF‐II‐1‐70) from a human plcental cDNA library, which contains the IGF‐II coding region and the 5′‐UTR associated with the third promoter. By using a 5′‐UTR‐specific probe from the clone, we found that this third 5′‐UTR is contained in the IGF‐II mRNA of 2.2 kb and is absent in the 3.2 kb IGF‐II mRNA. We also found an 0.9 kb transcript expressed in placenta, which hybridized strongly to the third 5′‐UTR specific probe but not to IGF‐II coding region probes. This finding might indicate the existence of an mRNA encoding an IGF‐II‐associated peptide. © 1992 Wiley‐Liss, Inc.
Transforming growth factor β and basic fibroblast growth factor synergistically promote early bovine embryo development during the fourth cell cycle
Authors: Larson R. C. , Ignotz G. G. , Currie W. B. 
Published: February 2005

AbstractDevelopmentally competent bovine blastocysts were produced by adding transforming growth factor β(TGFβ) and basic fibroblast growth factor (bFGF) to serum‐free cultures of in vitro produced, 2‐cell bovine embryos. The effects of TGFβ were evaluated because this growth factor signals synthesis and secretion of the extracellular matrix component fibronectin and its receptor. Previous investigations have demonstrated that fibronectin promotes early bovine embryo development in vitro. The effects of TGFβ can be potentiated by bFGF; bFGF itself is an effector of protein synthesis and a potent mitogen.A positive interaction between the 2 growth factors resulted in 38.8% of fertilized oocytes maturing beyond the 16‐cell stage; of these, 24.6% formed blastocysts. Transfer of early blastocysts produced using serum‐free medium supplemented with growth factors resulted in pregnancy in 3 of 9 recipients.These results support the hypothesis that TGFβ and bFGF act synergistically to promote development of bovine embryos beyond the “8‐cell block” observed in vitro. (c) 1992 Wiley‐Liss, Inc.
Fate of microinjected genes in preimplantation mouse embryos
Authors: Burdon Thomas G. , Wall Robert J. 
Published: February 2005

AbstractThe state of genes microinjected into mouse embryos was followed from the one‐cell to the blastocyst stage using the polymerase chain reaction (PCR). Microinjected DNA was detected in all one‐, two‐, and four‐cell injected embryos and in 44% of morula and 26% of blastocysts. Head‐to‐tail ligation of microinjected genes, a common feature of stably integrated transgene arrays, was detected in all embryos after injection of microinjected genes and occurred irrespective of the structure at the ends of the injected genes. Sensitivity of microinjected DNA to a methylation‐dependent restriction endonuclease Dpn I was lost in all embryos by the two‐cell stage (24 hr), indicating a change in DNA methylation, independent of transgene integration. Dissociation of blastomeres prior to compaction revealed a mosaic distribution of the microinjected DNA within the embryo and supports the notion that injected genes form a limited number of arrays, which segregate independently until they integrate into the genome or are degraded. Published 1992 Wiley‐Liss, Inc.
Factor in urinary extracts from pregnant women that inhibit mouse oocyte maturation in vitro
Authors: Sakakibara Ryuzo , Sakai Kazuya , Sakurai Yuko , Kohnoura Tae , Ishiguro Masatsune 
Published: February 2005

AbstractMouse oocyte maturation inhibitory factors, on the basis of inhibitory activity of spontaneous germinal vesicle breakdown (GVBD) of denuded mouse oocytes in culture, were extracted and partially purified by reversed‐phase resin adsorption and Sephadex G‐100 and G‐50 column chromatographies from the urine of pregnant women. Denuded oocytes obtained from ovaries of ICR mice underwent spontaneous GVBD by cultivation for 3 h in modified Krebs–Ringer's buffered solution, while this spontaneous GVBD was found to be inhibited by adding the final preparation (U‐D‐4) of urine. The inhibition was dose dependent, ranging from 0.6 to 10 μg protein/ml medium. Oocytes treated with U‐D‐4 and resuspended in control medium resumed GVBD. The molecular mass of U‐D‐4 was estimated to be less than 2,000 Da with gel filtration. Ether treatment failed to extract inhibitory factor(s) from U‐D‐4 and pepsin treatment inactivated U‐D‐4, indicating that inhibitory factor(s) in U‐D‐4 are peptide‐like substances. The inhibitory effect of U‐D‐4 on spontaneous GVBD was partially reversed in the presence of naloxone, a potent opioid antagonist. U‐D‐4s obtained from urine samples of pregnant women, nonpregnant women, and men showed the inhibitory effect on spontaneous GVBD; however, the activity of U‐D‐4 obtained from pregnancy urine was significantly more potent than those of the other urine samples. © 1993 Wiley‐Liss, Inc.
Isolation of sperm bindin from the oyster (Crassostrea gigas)
Authors: Brandriff Brigitte , Moy Gary W. , Vacquier Victor D. 
Published: February 2005

AbstractA method was devised for isolating the insoluble content of the acrosome granule of sperm of the oyster Crassostrea gigas. The method involves the dissolution of the entire cell, except for the acrosome granule, in the detergent sodium lauroyl sarcosinate (sarcosy I). The isolated acrosome granule content is ring‐shaped and is 84% protein by weight. SDS‐polyacrylamide gel electro‐phoresis of this material yields from 1 to 4 bands of 65,000; 53,000; 43,000 and 34,000 apparent molecular weight, all of which stain with the PAS reaction indicating the material is a glycoprotein. The 65,000 molecular weight component is always present, but the presence of the other three bands varies with each preparation. The isolated acrosome granules agglutinate formaldehyde‐fixed oyster eggs. A trypsin‐generated glycopeptide digest of oyster egg surfaces inhibits the agglutinin activity of the isolated acrosome granules. We propose that the acrosomal glyco‐protein material is oyster sperm bindin which functions as the adhesive substance bonding the sperm to the egg during fertilizaion.
Two pathways from glycogen to glucose‐6‐phosphate in sea urchin eggs with special reference to the difference between the species in the contribution ratio of each pathway
Authors: Hino Akiya , Tazawa Eigoro , Yasumasu Ikuo 
Published: February 2005

AbstractIn the unfertilized eggs of the sea urchins, Anthocidaris crassispina, Pseudocentrotus depressus, Hemicentrotus pulcherrimus, Mespilia globulus, Temnopleurus toreumaticus, Toxopeneustes pileolus, and Clypeaster japonicus, the activities of phosphorylase [EC 2.4.1.1], phosphoglucomutase [EC 2.7.5.1], exo‐l,4‐α‐glucosidase [EC 3.2.1.3], and hexokinase [EC 2.7.1.1] are very similar. In all species, only phosphorylase activity is higher in fertilized eggs than in unfertilized eggs. The concentrations of glycogen, glucose, GIP, G6P, ATP, ADP, and Pi; the products and substrates in reactions catalyzed by these enzymes, were measured in these eggs. Based on the concentrations of these compounds in the eggs, it is assumed that G6P is produced by the combined action of glucosidase and hexokinase in all species examined, and that it is also produced in the reaction catalyzed by phosphorylase and phosphoglucomutase in all species except A crassispina and P depressus. Glycogen was found both in supernatant and in precipitate fractions, which were obtained by adding perchloric acid. Glycogen in the precipitate seems to be protein‐bound. Whole glycogen level in the eggs is almost the same in all species examined, but the level of acid‐soluble glycogen, as well as GIP, is markedly lower in the eggs of A crassispina and P depressus than in the eggs of other species examined. Protein‐bound glycogen is utilized by glucosidase activity but not by phosphorylase activity, in contrast to acid‐soluble glycogen, which is utilized by both enzyme activities. Hence, it is assumed that the failure of G6P production by phosphorylase and phosphoglucomutase‐in A crassispina and P depressus eggs is due to a low level of acid‐soluble glycogen in these eggs.
Possible causal relation between the acrosome reaction and cross‐fertilization in the sea urchins hemicentrotus pulcherrimus and pseudocentrotus depressus
Authors: Aketa Kenji , Ohta Tadayuki 
Published: February 2005

AbstractSperm of Hemicentrotus pulcherrimus undergo the acrosome reaction in the jelly coat or on the surface of the vitelline layer of Pseudocentrotus depressus eggs and can fertilize the latter, whereas those of P depressus do not undergo the acrosome reaction even after they strike the vitelline layer of H pulcherrimus eggs and cannot cross‐fertilize.In the latter combination, however, if cross‐insemination is performed in the presence of homologous egg water, cross‐fertilization becomes less difficult than in normal seawater, and percentage cross‐fertilization rises as does percentage acrosome reaction. It is suggested that the cross‐fertilizability of this combination depends highly on the inductivity of the acrosome reaction. The reason why such a causal relation is observed is discussed.
Transfer of cultured rabbit embryos
Authors: Binkerd Pamela E. , Anderson Gary B. 
Published: February 2005

AbstractEmbryo transfer experiments were carried out to study the developmental capacity of cultured rabbit embryos when transferred to recipients of variable postovulatory maturity. Rabbit embryos were flushed from the oviduct at 26 hours postcoitum (pc) and cultured in a modified Ham's F‐10 medium supplemented with bovine serum albumin (BSA) for a period of 70 hours. At 96 hours pc the cultured embryos, which ranged from the early morula to the expanding blastocyst stage, were transferred to pseudopregnant recipients mated to vasectomized males 36 to 96 hours prior to the transfer procedure. Greatest embryo survival occurred when transfers were made to either the oviducts or uterine horns of recipients at 48 hours pc. Intermediate results for both implantation rates and number of young born were obtained with recipients at 36, 60, 72, and 84 hours pc. Transferred embryos consistently failed to survive the uterine environment of recipients 96 hours pc at transfer although this group was synchronous with embryonic chronological age. Oviductal transfers were generally more successful than uterine transfers. Markedly higher rates of embryo survival resulted from embryos that were collected 60 and 72 hours pc and transferred directly to synchronous recipients without an interim period of culture. Dissimilarity of development for in vivo grown rabbit embryos and those cultured in synthetic medium is demonstrated.
Effects of hydrolase inhibitors on fertilization of sea urchins: I. Protease inhibitors
Authors: Hoshi Motonori , Moriya Tsuneo , Aoyagi Takaaki , Umezawa Hamao , Mohri Hideo , Nagai Yoshitaka 
Published: February 2005

AbstractTo search the spermatozoa of sea urchins for their lysins, the eggs were inseminated in the presence of various protease inhibitors. Among them, two chymotrypsin‐specific inhibitors, chymostatin and N‐tosyl‐L‐phenylalanyl‐chloro‐methane, as well as p‐nitrophenyl p′‐guanidinobenzoate, inhibit fertilization of the sea urchins, Hemicentrotus pulcherrimus and Strongylocentrotus intermedius.A chymotrypsin‐like protease is presumed to be a lysin of the sea urchins, since the inhibition of fertilization by chymostatin is remarkably diminished if the eggs are pretreated with trypsin or chymotrypsin to break the vitelline coat before insemination, and since N‐tosyl‐L‐phenylalanyl‐chloromethane, and p‐nitrophenyl p′‐guanidinobenzoate, as well as chymostatin, inhibit the fertilization.In all the sea urchins so far studied, elevation of fertilization envelopes is inhibited by leupeptin, antipain, soybean trypsin inhibitor, and p‐nitrophenyl p′‐guanidinobenzoate, all of which are potent trypsin inhibitors.Synthetic inhibitors have cytotoxic side effects on the eggs, but the microbial and plant inhibitors have no such effects.
Isolation of bovine zonae pellucidae from ovaries with collagenase: Antigenic and sperm receptor properties
Authors: Gwatkin R. B. L. , Williams D. T. , Meyenhofer M. 
Published: February 2005

AbstractZonae pellucidae were collected from bovine ovaries by chopping, dispersing the chopped tissue with collagenase, sieving through nylon mesh screens, and pipetting. The zonae were free of corona cell processes when examined under the scanning electron microscope. Solutions of zonae obtained with collagenase exhibited the same antigenic and sperm receptor properties as those obtained without enzyme treatment.
Effect of the inhibitors of ion movements, verapamil and tetraethylammonium, on fertilization of mouse eggs in vitro
Authors: Shellenbarger David L. , Shapiro Bennett M. 
Published: February 2005

AbstractBetter than 75% fertilization of C57BL/6 mouse eggs with C57BL/6 sperm is obtained in vitro in a modified Kreb's‐Ringer‐bicarbonate medium containing 8 mM HEPES. No fertilization of obtained when Ca2+ is omitted from this medium. The drug verapamil, which interferes with Ca2+ channels and blocks the acrosome reaction [Schackmann et al, 1978] and fertilization in the sea urchin, also blocks fertilization of mouse eggs in vitro when included in complete medium at a concentration of 80 μg/ml. Tetraethylammonium, which inhibits delayed axonal potassium currents and prevents the acrosome reaction in sea urchin sperm, also completely inhibits fertilization of mouse eggs in vitro at a concentration of 5 mM. Tetramethylammonium, which does not inhibit potassium movements at the same concentration reduces fertilization by about 50%. The data are consistent with the hypothesis that ion movements are necessary for activation of the sperm and/or egg in mouse fertilization.
Induction of meiosis of Xenopus laevis oocytes by mianserine
Authors: Hanocq‐Quertier J. , Baltus E. 
Published: February 2005

AbstractMaturation of Xenopus laevis oocytes can be induced by mianserine, a tricyclic antidepressant. K+‐free medium facilitates this maturation process. Mianserine must be kept in contact with the oocytes during the whole process of maturation for maximal efficiency. It is inactive after injection into the oocytes. Mianserine induces the formation of maturation‐promoting factor (MPF) in the treated oocytes. Mianserine‐induced maturation is strongly inhibited by theophylline, even in K+‐free medium. Progesterone displays synergistic effects with mianserine for the induction of maturation. Likewise, oestradiol shows cooperative maturing effects with progesterone as well as with mianserine. It is suggested that mianserine exerts its primary effects on oocyte maturation by inhibiting a membrane adenylate cyclase.
Lectin‐mediated sperm agglutination of bufo arenarum and leptodactylus chaquensis spermatozoa
Authors: del Pino Enrique J. , Cabada Marcelo O. , Fonio María C. 
Published: February 2005

AbstractVarious plant lecins were employed in cell agglutination experiments to ascertain the presence of specific saccharides in the surface of B arenarum and L chaquensis spermatozoa. B arenarum spermatozoa were specifically agglutinated with Concanavalin A (Con A), phytohemagglutinin P (PHA‐P), and wheat germ agglutinin (WGA), but not with soybean agglutinin (SBA). In contrast, L chaquensis spermatozoa were strongly agglutinated by SBA, WGA, and PHA‐P. L chaquensis spermatozoa did not agglutinate with Con A even at high concentrations. Lectinmediated sperm agglutination was inhibited in the presence of specific lectinbinding sugars. Spermatozoa from both species were agglutinated randomly with all lectins suggesting a uniform distribution in the sperm surface of the lectinbinding saccharide ligands.B arenarum sperm agglutination induced by Con A is sensitive to temperature. B arenarum spermatozoa are more agglutinable at 24°C than at 4°C. These results suggest that lectin‐binding site mobility is necessary for sperm agglutination.
Differences in the rate of redistribution of receptors for concanavalin A in vivo and in vitro on spermatozoa from normal mice and from sterile mice carrying different T/t locus haplotypes
Authors: Dooher Gerald B. 
Published: February 2005

AbstractThe redistribution of receptors for fluorescein isothiocyanate‐conjugated concanavalin A (FITC‐con A) on mouse spermatozoa during maturation has been studied in vivo and in vitro using normal mice and sterile mice carrying two different lethal T‐locus haplotypes (tx/ty). Receptors for FITC‐con A, uniformly distributed on the head of functionally immature sperm within the proximal epididymis, become localized as the cells acquire functional maturity within the distal portion of the epididymis. Examining samples of epididymal sperm incubated for short periods of time in vitro, a similar increase in the proportion of discretely labeled cells is observed with time. Sperm from sterile tx/ty males also show redistribution of receptors for FITC‐con A in vivo and in vitro; however, a significantly smaller proportion of cells of the population achieve a discrete distribution of receptors comparable to that displayed on sperm from fertile mice. It is concluded that mouse sperm undergo redistribution of receptors for con A normally in acquiring functional maturity within the epididymis and upon liberation from the male urogenital tract; the sterility of tx/ty mice may be due to a genetically based impairment of plasma membrane reorganization reflected in sluggish redistribution of receptors for con A shown by these cells in vivo and in vitro.
Ultrastructural changes in the spermatid nucleolus during spermiogenesis in the guinea pig
Authors: Ohtomo Kazuo 
Published: February 2005

AbstractMorphological changes in the ring‐shaped nucleoli of spermatids were observed by electron microscopy during spermiogenesis in the guinea pig. In the early acrosomal phase each nucelolus was composed of a bundule of fibers about 25 nm in diameter and 250 nm in length. In cross section the fibers were seen to be closely packed in hexagonal fashion. From the early maturation phase through maturation of the spermatids the fibers of the nuceloli appeared to be replaced by a fine filamentous structure. As the condensation of chromatin proceeded, the filamentous structure decreased in density, and finally the space of the nucleolus was replaced by a nucleolar vacuole.
The effects of aphidicolin and α‐amanitin on DNA synthesis in preimplantation mouse embryos
Authors: Cozad Karen M. , Warner Carol M. 
Published: February 2005

AbstractThe effects of aphidicolin and α‐amanitin on DNA synthesis by preimplantation mouse embryos were studied. It was found that both blastocyst and 8‐cell embryos showed marked inhibition of 3H‐thymidine incorporation into DNA by aphidicolin at concentrations of 20–50 μg/ml. However, aphidicolin did not inhibit the conversion of morula embryos to blastocyst embryos, although aphidicolin‐treated blastocysts lost their blastocoel and collapsed into a compact form after prolonged exposure to the drug. Both 8‐cell and blastocyst embryos were found to be susceptible to inhibition of DNA synthesis by α‐amanitin.