bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of demecolcine (colcemid) on goldfish oocyte meiosis in Vitro
Authors: Habibi Hamid R. , Lessman Charles A. 
Published: February 2005

AbstractGerminal vesicle migration (GVM) and dissolution (GVD) were studied in goldfish oocytes treated with 17‐α,20–β‐dihydroxyprogesterone (DHP) and/or demecolcine (DE; a colchicine derivative also known as colcemid) in vitro. DE (100 μg/ml) in the presence of DHP, enhanced steroid‐induced GVM, after both 24 and 48 hr of incubation and significantly reduced the DHP ED50 value for GVM. Similarly, administration of DE alone elicited a significant, dose‐related increase in GVM after 24 or 48 hr of incubation. The presence of DE, either alone or in combination with DHP, was without effect on GVD. The effect of DE was also tested on ooplasmic viscoelasticity in goldfish follicles subjected to a centrifugal force (160g for 1 min). Preincubation (24 hr) of goldfish follicles in DE significantly influenced the direction and the extent of the centrifugally induced GV movement along the axis of centrifugal force in a dose‐related fashion. The present results provide support for the hypothesis that cytoskeletal components, such as microtubules that are sensitive to DE, are involved in the mechanism of GVM in goldfish oocytes.
Effects of the calcium channel blocker diltiazem on the excitability of mouse oocytes
Authors: Yoshida Shigeru 
Published: February 2005

AbstractEffects of the organic Ca antagonist diltiazem on Ca channels were studied in ovulated and unfertilized oocytes of the mouse by using intracellular recording techniques. The resting potential was not affected by diltiazem. The threshold level of the Ca action potential shifted slightly toward positive voltages with diltiazem concentration, but the shift was not statistically significant. The overshoot and maximum rate of rise of the Ca action potential were inhibited by the drug in a dose‐dependent manner, but higher amounts of diltiazem were necessary to cause similar blocking effects on Ca channels in mouse oocytes than in other differentiated cells. Increases of external concentration of Ca2+ antagonized the degree of diltiazem inhibition. However, the sequence of block of Ca2+, Sr2+, and Ba2+ currents was different for diltiazem vs Cd2+. It is suggested that diltiazem inhibition can not be explained by simple competitive scheme, ie, antagonism between diltiazem and permeant cations does not occur at the same binding site associated with the Ca channel in mouse oocytes.
Study on oocyte maturation and activation of the common prawnpalaemon serratus(Pennant): Relationship between oocyte maturation and the molt cycle cytological aspects
Authors: Cledon Philippe 
Published: February 2005

AbstractA detailed chronology of the cytological events related to maturation that take place within the reproduction molt cycle has been established. It has been shown that oocytes, initially arrested at prophase I, resume meiosis when approaching stage D1‴ of the molt cycle, ie, 4–5 days before molting. The following steps characterize this premolt period of oocyte maturation: nuclear envelope folding, nucleolar dissociation, condensation of the chromosomes, and beginning of the breakdown of the nuclear envelope (GVBD). At the ultrastructural level, it has been confirmed that GVBD actually takes place at the D1‴−D2stage transition, when the germinal vesicle still occupies a central position in the oocyte. The migration of the chromosome takes only a few hours and begins approximately 4 hr before molting. It is only 1–2 hr before molting that the divalent chromosomes that are not yet organized in a metaphase plate become visible at the surface of the oocyte. They lay in a nucleoplasmic area no longer limited by the nuclear envelope. Metaphase I is reached a few minutes after molting. A second meiotic block appears at this stage, which persists until spawning, ie, for about 24 hr. Fertilization occurs at the moment of spawning. In vitro fertilization experiments demonstrated that fertilization normally triggers the release of the second meiotic block. Extrusion of the two polar bodies can be easily observed using a method for clearing and staining the oocytes in toto.
Lectin binding sites on the plasma membrane of epididymal and ejaculated chimpanzee sperm
Authors: Young Leona G. , Gould Kenneth G. , Hinton Barry T. 
Published: February 2005

AbstractLectins have been used to analyze variations in the distribution and density of exposed saccharides of the sperm plasma membrane during physiologic maturation and after ejaculation. Studies have been conducted in a number of nonprimate species but have been conducted to only a limited extent in nonhuman primates. In this study, pure suspensions of chimpanzee sperm from the caput and cauda epididymis and from the ejaculate were labeled with lectins conjugated to fluorescein isothiocyanate in order to visualize changes in the distribution of exposed membrane glycocomponents. The lectins used were Con A, DBA, RCA‐I, and WGA. Con A binding showed minimal change during epididymal transit, with an increased binding to the flagellum after ejaculation. DBA binding was relatively constant in all specimens. RCA‐I showed distinct changes in binding pattern between epididymal and ejaculated sperm. On ejaculated sperm strong fluorescence was limited to the posterior head and to the midpiece. WGA binding increased during epididymal passage and decreased after ejaculation. There appears to be a wide variety of saccharide groups available for lectin binding on the surface of epididymal and ejaculated chimpanzee sperm. The general similarity in binding patterns of caput and cauda epididymal chimpanzee sperm exposed to Con A and DBA might reflect the fact that sperm morphology does not change during epididymal transit in this species, thus implying a more stable membrane structure than is present in other primates so far studied.
Sperm‐egg interactions in the shrimp Rhynchocinetes typus
Authors: Barros C. , Dupré E. , Viveros L. 
Published: February 2005

AbstractSperm‐egg interaction in Rhynchocinetes typus was studied with the phase‐contrast and scanning electron microscopes. R typus spermatozoa present in the vas deferens have the shape of a round‐headed nail. After contact with seawater it is possible to observe the unfolding of the rays or stellate arms, giving the spermatozoon the appearance of an inverted umbrella. From the center of the flat face of the umbrella emerges a spike with longitudinal striations. Ovarian eggs and spermatozoa were mixed in vitro by agitating them for two minutes in Millipore‐filtered seawater. The first gamete contact was established by the spermatozoon through the tip of the spike, which exerted a lytic action on the egg envelopes. After the rigid spike was completely inside the egg, the rays became aligned parallel to each other and began to enter the eggs. Toward the final stages of ray entry, it was possible to observe fusion of the ray membranes with one another, and later the fusion process continued toward the tip of the radial spines. Concomitantly, the egg surface that surrounds the sperm swelled in a circular fashion and formed a fertilization cone. After the spermatozoon entry was complete, a scarlike mark appeared at the place on the egg surface through which penetration occurred. The whole penetration process was completed within 45‐60 minutes.
Estimation and manipulation of glutathione levels in prepuberal mouse ovaries and ova:Relevance to sperm nucleus transformation in the fertilized egg
Authors: Calvin Harold I. , Grosshans Kurt , Blake Emily J. 
Published: February 2005

AbstractGlutathione (GSH), the major low‐molecular‐weight thiol in mammalian cells, is believed to be a necessary factor for the transformation of the disulfide‐stabilized sperm nucleus into the male pronucleus after fertilization. Its concentration in mouse ova, isolated from the ampulla of the oviduct after hormone‐induced superovulation of 3–4‐week‐old mice, has been determined by an enzymic cycling microassay. The level found was 1.80 pmol per ovum. Mean ovum diameter was estimated as 71–72 μm, indicating a GSH concentration of 9–10 mM in the mouse egg. Administration of L‐buthionine S, R‐sulfoximine, an inhibitor of GSH biosynthesis, during the 2 days preceding ovulation, reduced ovum GSH content below 0.20 pmol (<1.0 mM). The mean GSH concentration of the hormone‐stimulated ovaries was reduced from 3.2 mM to 0.2 mM under these conditions.It has also been demonstrated that measurement and manipulation of ovum and ovarian levels of GSH can aid in studying its function in ovaries, ova, and early embryos. Hormone‐induced superovulation was achieved in BSO‐treated prepuberal C57B1/6 X SJL mice whose ovaries contained less than 10% of control levels of GSH. Over 50% of the isolated ova were fertilized in vitro. However, abnormal one‐cell embryos resulted in which the maternally derived pronucleus coexisted with an unchanged sperm nucleus, thus confirming that adequate levels of GSH are necessary for initiating transformation of the fertilizing sperm nucleus.
Cell surface markers of mouse primordial germ cells defined by two monoclonal antibodies
Authors: Hahnel A. C. , Eddy E. M. 
Published: February 2005

AbstractMonoclonal antibodies EMA‐1 and EMA‐6 bind to cell surface antigens of mouse primordial germ cells between 7 and 14 days of development. Primordial germ cells can be identified by alkaline phosphatase activity, and EMA‐1 and EMA‐6 apparently recognize this same population of cells prior to 14 days of development. EMA‐1 labels primordial germ cells in 8‐ to 13‐day mouse embryos and EMA‐6 in 8‐ to 10‐day embryos. A difference in the cells recognized by EMA‐1 and the lectin Dolichos biflorus agglutinin in early embryos suggests that these probes may be useful for studying primordial germ cells in situ or for isolating them from mouse embryos.
Immunological evidence that a 305‐kilodalton vitelline envelope polypeptide isolated from sea urchin eggs is a sperm receptor
Authors: Acevedo‐Duncan Mildred , Carroll Edward J. 
Published: February 2005

AbstractDirect isolation of the sea urchin egg vitelline envelope with intact sperm receptors is difficult because the envelope is firmly attached to the egg plasma membrane. We now report a method for producing an inseminated egg preparation in Strongylocentrotus purpuratus (using soybean trypsin inhibitor [STI] and Ca2+, Mg2+‐free seawater) that contains an elevated vitelline envelope (VE*‐STI). The VE*‐STI is devoid of cortical granule material, and supernumerary sperm do not detach postinsemination, suggesting that the VE*‐STI contains active sperm receptors. VE*‐STIs contain a 305‐kD polypeptide and additional components that range from 225 to 31 kD, whereas the 305‐kD polypeptide was considerably reduced in VE*s. Electrophoresis of sperm receptor hydrolase digests of VE*‐STIs showed that the 305‐kD polypeptide and several other envelope polypeptides are protease substrates. Univalent Fab fragments against VE*s, VE*‐STIs, and 305 and 225‐kD polypeptides blocked sperm binding and fertilization in an Fab concentration‐dependent manner. The 305 and 225‐kD polypeptides were localized in the VE*‐STI using indirect immunofluorescence. Enzyme‐linked immunosorbent assays showed that the 305 and 225‐kD polypeptides share determinants, suggesting that the 225‐kD polypeptide may be derived from the 305‐kD polypeptide by the proteolysis that occurs at the cell surface during fertilization. Fab fragments against S purpuratus VE*‐STI antigens neither bound to nor blocked homologous sperm binding and fertilization of Lytechinus variegatus eggs. Cross fertilizability occurred to the extent of 5% or less between L variegatus and S purpuratus, therefore, we conclude that the 305 kD‐polypeptide isolated from S purpuratus is a species‐specific vitelline envelope sperm receptor.
Equine zona pellucida and capsule: Some physicochemical and antigenic properties
Authors: Bousquet Daniel , Guillomot Michel , Betteridge Keith J. 
Published: February 2005

AbstractThe capsule which surrounds the pre‐attachment equine embryo has been compared with the zona pellucida (zp) that it replaces, as well as with the rabbit blastocyst coverings, by means of physicochemical and immunological methods. Trypsin solution at pH varying between 7.5 and 9.0 completely solubilized the capsule, as did Na borohydride. However, solutions of pH 2.0 or 12.0, urea, high temperature (65°C, 60 min or 80°C, 30 min), mercaptoethanol and dithiothreitol were able to solubilize the zp but not the capsule at the concentrations used. Indirect immunofluorescence on cryostat sections and whole mounts of fresh or frozen‐thawed material showed that 1) common antigens are shared by equine, porcine and bovine zp; 2) day 7 to day 15.5 capsule reacted with anti‐capsule‐serum but not with anti‐zp‐serum except for a few patches on the surface of the capsule; 3) anti‐capsule‐serum, but not anti‐zp‐serum, reacted with the capsular material recovered along with a broken day 27.5 conceptus; 4) anti‐capsule‐serum does not react with rabbit blastocyst coverings; 5) anti‐capsule antibodies can be absorbed from the anti‐capsule‐serum by uterine proteins from either pregnant or non‐pregnant mares; and 6) the capsule does not contain mouse laminin‐like material.
A protein family immunorelated to a sperm‐binding protein and its regulation in human semen
Authors: Metafora S. , Lombardi G. , De Rosa M. , Quagliozzi L. , Ravagnan G. , Peluso G. , Abrescia P. 
Published: February 2005

AbstractIn human seminal plasma a family of proteins that is immunologically related to the RSV‐IV protein secreted under androgen control from the epithelium of the rat seminal vesicles was detected by a radioimmunoassay. Evidence for the origin of these antigens from human seminal vesicle is presented. Quantitative measurements of this family of proteins were performed in men with low levels of serum testosterone (idiopathic hypogonadotropic hypogonadism) and in individuals having serum testosterone in the normal range of values but carrying sex chromosome aberrations (Klinefelter's syndrome). In the first case we have found a marked decrease in the total amount of the RSV‐IV‐related proteins. An increase of about 40% in the total amount of these antigens was obtained in these subjects by gonadotropin treatment. A decreased amount of these proteins was also detected in the subjects affected by Klinefelter's syndrome. The possibility that some factor(s) under genetic control is involved, in addition to testosterone, in the regulation of this family of proteins is discussed.
Characterization of hatching‐associated changes in the sea urchin fertilization envelope
Authors: Uher Vera Irene , Carroll Edward J. 
Published: February 2005

AbstractThe embryo of the sea urchin Strongylocentrotus purpuratus hatches from the fertilization envelope (FE) via synthesis and secretion of a hatching enzyme and by ciliary activity. Although the basic characteristics of the hatching enzyme are known, little is understood about changes in the FE during hatching. We have studied the biochemical changes in FEs during hatching. Polyacrylamide gel analysis revealed an increasingly complex polypeptide spectrum of the extractable fraction of FEs isolated during development. Immunoblotting of these polypeptides (using antiserum against the soluble polypeptides extracted from FEs isolated at 30 minutes postinsemination) revealed a decrease in the soluble FE components during hatching. Immunochemical analysis of hatching medium showed a strong correlation between the soluble FE components released and the hatching interval. Immunoblotting of hatching media indicated the presence of soluble FE polypeptides of similar and lower molecular weights than those obtained for extracts of FEs. These results imply that the hatching‐associated changes in the FE of S purpuratus occur via proteolysis of FE components, which are derived from the paracrystalline protein fraction, a subset of cortical granule proteins.
Intracellular localization of argyrophilic proteins in the maturing oocyte, fertilized egg, and spermatozoa of the starfish, Asterina pectinifera
Authors: Amikura Reiko M. , Yamada Hisafumi , Hirai Setsuro , Nagano Hiroshi 
Published: February 2005

AbstractChanges in intracellular localization of argyrophilic proteins visualized as silver‐stained particles by nuclear organizer region (NOR)‐silver staining were investigated in starfish oocyte maturation. The silver‐stained particles were localized in the germinal vesicle and nucleolus of immature oocytes and dispersed into the cytoplasm at the time of germinal vesicle breakdown (GVBD). In the mature egg cytoplasm, silver‐stained particles were distributed on yolk‐like granules with diameters of 0.3–1.0 μm. In spermatozoa, silver‐stained particles were detected heavily in the acrosome and centrosomes but few were detected in the nucleus, whereas they were present in the male pronucleus of fertilized eggs. The silver‐stained particles were removed by pretreatment of eggs with protease but not with nuclease. These results indicate that argyrophilic proteins disperse to the egg cytoplasm during GVBD and might be incorporated to the male pronucleus from the egg cytoplasm in fertilization. The morphological changes from chromosomes through chromosome vesicles to female pronucleus were also observed with light microscopy after NOR‐silver staining.
Effects of induced ovulation by pregnant mare's serum and human chorionic gonadotropin on the sex ratio of mouse fetuses
Authors: Sakai N. , Endo A. 
Published: February 2005

AbstractThe sex ratio of the fetuses from mice treated with pregnant mare's serum (PMS)/human chorionic gonadotropin (HCG) to induce ovulation did not differ appreciably from that of spontaneously ovulated controls. Rather, an intriguing observation was that the sex ratio in the right uterine horns tended to be lower than that in the left horns in both spontaneously ovulated controls and PMS/HCG‐treated groups. We speculate on its possible relation to the observed right‐left asymmetry of horn sizes (number of fetuses in the horn).
Embryonic development in culture of two dasyurid marsupials, Sminthopsis crassicaudata (gould) and Sminthopsis macroura (spencer), during cleavage and blastocyst formation
Authors: Selwood Lynne 
Published: February 2005

AbstractEmbryos of Sminthopsis crassicaudata and Sminthopsis macroura were cultured for up to 96 hours during cleavage and early expansion of the blastocyst in Dulbecco's modified Eagle's medium (DMEG), DMEG containing 2.76 gm/liter sodium lactate (DMEGL), DMEG containing 3.5 gm/liter galactose (DMEGAL), DMEG containing 15 ng/ml progesterone (DMEGP) or 150 ng/ml progesterone (DMEGP10), and DMEGL containing 15 ng/ml progesterone (DMEGLP).The disappearance of sperm was used to indicate the time of ovulation (day 0). Fertilized eggs were found in the uterus at the end of day 1, four‐cell stages at the end of day 2, and embryos completing the fourth division by the end of day 3 in S. macroura and day 4 in S. crassicaudata. Estimated developmental times in culture were similar to those obtained in vivo. In both species, the first two divisions take about 24 hours, cleavage is arrested for 24 hours or longer at the rounded four‐cell stage, and the third and fourth divisions take a further 24 hours. The blastocyst expands during the next 24 hours in which time the fifth and sixth divisions occur. It was possible to culture embryos from S. macroura but not S. crassicaudata over the four‐cell stage to early expanding blastocysts.DMEGAL did not support cleavage in culture. DMEG, DMEGL, DMEGP, DMEGP10, and DMEGLP all supported culture during cleavage and early blastocyst expansion. Blastocyst expansion was slightly enhanced using media containing sodium lactate. More embryos completed the fifth division and formed expanding blastocysts in DMEG, DMEGL, and DMEGLP.
Sea urchin testicular cells evaluated by fluorescence microscopy of unfixed tissue
Authors: Simpson Marcia V. , Poccia Dominic 
Published: February 2005

AbstractA procedure is presented for rapid, quantitative evaluation of cell and nuclear types present in the male gonad of the sea urchin. Vitally stained whole mounts of tissue fragments or dissociated cells are prepared, which reveal detailed 3‐dimensional chromatin patterns and enough cytoplasmic features to provide reliable markers for most of the somatic and germ line cell types. Representative cellular morphologies are described. Nuclear volume changes during spermatogenesis are quantified. Spermatid nuclei contain an apparently interconnected network of heterochromatin. Regions relatively devoid of chromatin decrease in size as nuclear condensation proceeds and spherical nuclear shape is maintained. The major decrease in nuclear volume occurs prior to the late spermatid stage. The volume of the spermatozoan nucleus is achieved by the smallest late spermatid nucleus before the change from spherical to conoid morphology. The relationship of this morphological transition to sperm histone dephosphorylation is discussed.
Impaired ability of human spermatozoa to penetrate zona‐free hamster oocytes: Is a postacrosomal sheath anomaly involved?
Authors: Courtot A. M. , Escalier D. , Jouannet P. , David G. 
Published: February 2005

AbstractWe selected 17 infertile men whose sperm ultrastructural study revealed at least 70% of spermatozoa with postacrosomal sheath (PAS) anomalies. Among the other sperm head defects, those affecting the nuclear shape were most frequently encountered and were highly correlated with PAS anomalies (r = +0.71; P < .01). PAS anomalies were also correlated with chromatin condensation defects (r = +0.67; P < .01) and acrosome anomalies (r = +0.53; P <.05). Those spermatozoa were tested for their ability to penetrate zona‐free hamster oocytes and were compared to a control sperm population. It was shown that sperm head morphological anomalies impaired the ability of spermatozoa to attach to and penetrate the oocyte. The highest significant and negative correlations were found between the penetration rate and 1) the percentage of spermatozoa with PAS anomalies (r = −0.81; P < .01) and 2) the percentage of spermatozoa with nuclear shape anomalies (r = −0.66; P < .01). The effect of PAS anomalies on human fertilization process are discussed.
Development of mouse embryos in vitro is affected by strain and culture medium
Authors: Dandekar Pramila V. , Glass Robert H. 
Published: February 2005

AbstractOne‐cell and two‐cell embryos from three random‐bred strains of mice–CF1, Dub:(ICR), and CFW (Swiss‐Webster)–were cultured to the blastocyst stage in Spindle's, Earle's, Ham's F10, Whittingham's T6, or Hoppe and Pitts' medium. CFW embryos were more successful than CF1 and Dub:(ICR) embryos in developing to the blastocyst stage in all five media. Dub:(ICR) and CFW two‐cell embryos showed the best development in Spindle's, Whittingham's T6, and Hoppe and Pitts', whereas CF1 two‐cell embryos were most successful in developing in Hoppe and Pitts' medium. Similar results were obtained with one‐cell embryos, although fewer developed to the blastocyst stage, and T6 rather than Hoppe and Pitts' medium sustained the best development of CF1 one‐cell embryos. For all strains, the least successful development was in Ham's F10, but CFW embryos did show good development in this medium. In addition to the effects of various media on mouse embryo development, our results indicate that the strain of mouse used for the bioassay of media is of critical importance. Random‐bred CFW (Swiss‐Webster) mice are as suitable as a hybrid strain for this purpose.