bluuebunny/crossref_metadata_2025_split huggingface dataset:
Environment and medium volume influence in vitro fertilisation of pig oocytes
Authors: Coy P. , Martínez E. , Ruiz S. , Vázquez J.M. , Roca J. , Gadea J. 
Published: September 2008

SummaryOviductal oocytes (n = 795) were obtained from ovulation-induced prepubertal gilts. In the first experiment, different parameters related to in vitro fertilisation (IVF) were compared in the presence and absence of cumulus matrix (which is shed with the oocytes at ovulation.) The results show that the presence of this matrix is beneficial because the rates of fertilisation (69%) (number of monospermic oocytes/total number of healthy mature oocytes; 42%), and the median number of spermatozoa per oocyte (1.52±0.06), were improved with respect to those obtained in its absence (54%, 22% and 2.33 ± 0.08, respectively; p<0.01). In the second experiment the effect of two different volumes of co-incubation medium (2 ml and 0.4 ml) on the same parameters of porcine IVF were compared. No significant differences between volumes were observed, except in the mean number of spermtozoa per oocyte and the percentage of dispermic oocytes.
The late events of fertilisation in the penaeoidean shrimpSicyonia ingentis
Authors: Hertzler Philip L. , Clark Wallis H. 
Published: September 2008

SummaryAntibodies to sea urchin β-tubulin and mammalian heavy neurofilaments were to used the late events of fertilisation in the penaeoidean shrimpSicyonia ingentis. The neurofilament antibody fortuitously stained centrosomes in eggs, as well as the subacrosomal region and acrosomal filament in sperm. The neurofilament antibody also stained a cortial site in eggs which was associated with the positioning of the mitotic spindle. During pronuclear migration, a large maternal microtubule during syngamy, while the sperm centrosomes formed the poles of the first mitotic spindle. Colcemid treatment modulated the size of the mitotic spindle and blocked pronuclear migration.
Moderate heat treatment increases the penetrability of zonae pellucidae of salt-stored mammalian oocytes by spermatozoa
Authors: Yanagimachi Ryuzo , Katayose Haruo , Killian Gary , Lee Chin N. , Carrell Douglas T. , Huang Thomas T.F. 
Published: September 2008

SummaryThe zona pellucida of mammalian oocytes stored in highly concentrated solutions of neutral salts is known to retain its biological and biochemical properties. However, the zona may become resistant to sperm penetration as the storage period is increased. In cattle and hamsters, the penetrability of zonae of salt-stored oocytes was restored or increased by treating the oocytes with moderate heat without altering the gross morphology of the zona. Although this technique did not work for salt-stored human ova, this may have been due to the use of so-called inseminated- unfertilised ova which (1) may have been fertilised but failed to activate, or (2) were not fertilised because of functionally defective zonae.
Localisation and capacitation-dependent loss of buffalo sperm-coating antigens shared with rat sperm
Authors: Venditti Paola , Bergamo Paolo , Talevi Riccardo , sansone Giovanni , Abrescia Paolo 
Published: September 2008

SummaryThe heterodimeric sperm-coating protein CFS was previously localised on the middle-piece region of rat spermatozoa by anti-CFS rabbit antibodies. CFS-immunorelated antigens were detected in the secretion of the water buffalo seminal vesicle by protein electrophoresis and Western blotting. Spermatozoa from buffalo epididymal cauda were incubated with the rat antigen and, upon immunostaining with anti-CFS antibodies and goat anti-rabbit fluorescein isothiocyanate (FITC)-conjugated IgGs, CFS was found attached on both the post-acrosomal region and the tail. Indirect immunofluorescence analysis permitted the localisation of CFS-related antigens on the same domains of buffalo ejaculated spermatozoa. These results suggest that the buffalo antigens not only share some epitopes with the homologous rat antigen but may also have some of its functional properties. Ejaculated spermatozoa were capacitatedin vitroand then assayed for their content of CFS-like antigens. An inverse relationship was found between the levels of capacitation and the amounts of antigens detected, thus suggesting that thein vitrotreatment was effective at removing CFS-related proteins from the cell surface. Titration of these proteins to proteins to monitor plasma membrane changes during sperm manipulation or to evaluate sperm quality is proposed.
Confocal ratio-imaging of intercellular pH in unfertilised mouse oocytes
Authors: House C.R. 
Published: September 2008

SummaryUnfertilised mouse oocytes absorbed the pH-sensitive fluoroprobe SNARF-1-AM (carboxyseminaphthorhodafluor-1-acetoxymethylester), the ester being hydrolysed by an intracellular esterase. Ratioimaging of oocytes containing the resultant SNARF-1 excited by laser light (514nm) has been obtained by scanning confocal microscopy with appropriate barrier filters to monitor emission maxima about 590 and 640 nm recorded simultaneously in separate channels of the framestore. Images produced by pixel-by-pixel division of these channel images showed uniform distribution of SNARF-1 in equatorial regions in most cells. However, in some oocytes regions (about 4 μm diameter) with smaller ratios (i.e. lower pHi) were detected. The relation between the ratio of emitted maxima and the extracellular pH (pHo) in the presence of nigericin allowed a calibration procedure to determine the intracellular pH (pHi). With this mehod pHiwas estimated to be 7.13±0.05 (mean ± SEM,n= 31). Whereas the application of a weak acid (butyric) caused a fall in the ratio and hence in pHi, exposure to weak bases (NH4Cl or trimethylamine) caused a rise. Large changes in pH0. did not evoke corresponding changes in the ratio and hence in pHi. Addition of 5% CO2to the external solution buffered at the usual value of pH 7.4, however, did cause a fall in the ratio which was reversible only when HCO3−was present in the external solution.
Methylation in fertilised and parthenogenetic preimplantation mouse embryos
Authors: Croteau S , Menezo Y 
Published: September 2008

SummaryDNA methylation is one of the proposed biochemical mechanisms involved in cell differentiation and in genomic imprinting, and DNA methyltransferase (DMT) is a key enzyme in the embryo since mutation of its gene is lethal early in development. In order to verify that non-viability of uniparental embryos was not due to a defect in the regulation of DMT activity, we compared the metabolism of methylation in parthenogenetic embryos (maternal genome) and in fertilised embryos (maternal and paternal genomes). As regards total methylation, estimated by a measure of S-adenosyl methionine (SAM) and S-adenosyl homocysteine (SAH) formation, no significant difference was found between the two kinds of embryos during preimplantation development. Mean values were 4.5 ± 0.6 fmol (SAM +SAH)/h per 2-cell embryo and 0.40 ± 0.05 fmol SAH/h per 2-cell embryo, i.e. a SAH/(SAM + SAH) ratio of 9%; there was no detectable SAH formation in blastocysts. The same observation can be made for DMT activity, with mean values of: 7.8 fmol/h per oocyte, 8.5 fmol/h per 2-cell embryo, 6.1 fmol/h per 4-cell embryo, 4.1 fmol/h per morula, and no detectable activity in blastocysts. Total methylation as well as DNA methylation is characterised by a progressive drop in activity during preimplantation development.
The role of exogenous energy substrates in blastocoele fluid accumulation in the rat
Authors: Brison Daniel R. , Leese Henry J. 
Published: September 2008

SummaryPreimplantation mammalian development culminates in the formation of a fluid-filled cavity, the blastocoele, which is a prerequisite for successful implantation and further development. The blastocoele is enclosed by a single layer of polarised cells, the trophectoderm, which is the first epithelium formed in development. In embryos of the mouse and the rabbit, a basolaterally located Na+/K+-ATPase hydrolyses ATP to drive the vectorial transport of ions, which is responsible for the accumulation of blastocoele fluid. Using non-invasive assays of energy substrate consumption and blastocoele fluid accumulation, experiments were carried out on single preimplantation rat embryos, to establish: (1) the roles of the Na+/K+-ATPase and exogenous energy substrates, and (2) the relationship between the consumption and metabolism of energy substrates and fluid accumulation, during blastocoele cavity formation in this species. Ouabain 0.5 mM and energy-substrate-free medium both caused an inhibition in the number of embryos forming a blastocoele in culture, and also reduced the rate of fluid accumulation by day 5 blastocysts collapsed in cytochalasin-D and allowed to re-expand. Ouabain also reduced the consumption of glucose (but not pyruvate) and the production of lactate by re-expanding blastocysts. In the absence of the inhibitor, a direct relationship was seen between fluid accumulation and both glucose (but not pyruvate) consumption and lactate production. However, ouabain had no effect on intact, expanded blastocysts. These results suggest that (1) a basolaterally located, ouabain-inhibitable Na+/K+-ATPase is involved in rat blastocoele formation, (2) this process is dependent on exogenous energy substrates, and (3) there may be a direct relationship between the metabolism of glucose via glycolysis, and blastocoele fluid accumulation.
In vitro development of morulae from immature caprine oocytes
Authors: Keskintepe Levent , Darwish Gamal M. , Younis Abdelmoneim I. , Brackett Benjamin G. 
Published: September 2008

SummaryThe effects of medium supplementation with oestrous goat serum and glycoprotein hormones on caprine oocyte maturation in vitro (IVM) were evidenced by proportions of resulting ova completing in vitro fertilisation (IVF) and development to the morula stage. Oocyte-cumulus complexes (OCCs) were harvested in follicular fluid from 2–5 mm diameter follicles. Oocyte maturation took place during 27 h in TCM-199 supplemented with 20% oestrous goat serum, oestradiol-17β (1.0 μg/ml), and either (a) 0.5 μg FSH/ml, (b) 100 μg LH/ml, (c) 100 μg LH + 0.5 μg FSH/ml, (d) 100 μg hCG + 0.5 μg FSH/ml, (e) 0.5 μg TSH/ml or (f) no added glycoprotein hormone (control). Of 353 immature oocytes cultured in seven experiments, 311 (88.1%) exhibited cumulus expansion at the end of the IVM interval; all normalappearing OCCs were inseminated. In vitro insemination was with ejaculated sperm treated with heparin (10 μg/ml) and caffeine (0.4 μg/ml). Proportions (%) of inseminated ova that were fertilised (cleaved) and that reached the morula stage after IVM with (a) FSH, (b) LH, (c) LH + FSH, (d) hCG + FSH, (e) TSH and (f) no added glycoprotein hormone were (a) 22/52 (42.3%) and 9/52 (17.3%), (b) 25/54 (46.3%) and 14/54 (25.9%), (c) 52/65 (80.0%) and 26/65 (40.0%), (d) 48/78 (61.5%) and 22/78 (28.2%), (e) 14/54 (25.9%) and 4/54 (7.4%), and (f) 11/50 (22.0%) and 1/50 (2.0%), respectively. All treatments yielded better results than IVM with no added glycoprotein hormone. After IVM with added LH + FSH higher proportions of oocytes were fertilised (p<0.05), and higher proportions reached the morula stage (p<0.05) when compared with other treatments.
Cytochalasin B does not block sperm penetration into denuded starfish oocytes
Authors: Kyozuka Keiichiro , Osanai Kenzi 
Published: September 2008

SummaryDuring fertilisation in starfish oocytes, the fertilisation cone develops temporarily beneath the penetrating sperm. The role of the fertilisation cone in sperm incorporation in the starfish Asterias amurensis was examined using cytochalasin B (CB). CB (2 μM) allowed sperm acrosomal process–egg plasma membrane fusion and egg activation, but inhibited the development of the fertilisation cone containing actin microfilaments. When sperm were added to intact oocytes (with the jelly coat and vitelline coat) in seawater containing CB, the sperm head did not penetrate the fertilisation membrane. Although the acrosomal process fused with egg plasma membrane, the sperm head remained outside the fertilisation membrane. On the other hand, denuded oocytes without the jelly coat and vitelline coat allowed sperm penetration even in the presence of 2 μM CB. Electron microscopy revealed that sperm organelles, including the acrosomal process, nucleus, mitochondrion and tail, were incorporated into the slightly electron-dense cytoplasm, which was similar to the cytoplasm of the fertilisation cone. These results show that the development of the fertilisation cone/actin filament complex is not essential for incorporation of the sperm, since incorporation can occur in denuded oocytes. However, the cone is required for fertilisation of intact oocytes, suggesting that this actin-filament-containing structure is necessary for getting the sperm through the outer egg coats.
Sperm-egg fusion in the sea urchin is blocked in Mg2+-free seawater
Authors: Mohri Hideo , Hamaguchi Yukihisa , Hamaguchi Miyako S. , Sano Kiyoshi , Shirakawa Hideki , Nakada Ken , Miyazaki Shunichi 
Published: September 2008

SummaryMagnesium ions as well as calcium ions are required for successful fertilisation in sea urchins. In the absence of Mg2+spermatozoa attached to the egg plasma membrane, their acrosomal processes passing through the vitelline envelope, but could not enter the egg cytoplasm (Sanoet al, Dev. Growth Differ.22, 531–41,1980). Such an individual spermatozoon was observed microscopically to resume entry into the egg immediately after the addition of a sufficient amount of Mg2+to the surrounding medium. Neither any change in membrane potential nor an increase in intracellular Ca2+concentration of the egg was observed after insemination in the absence of Mg2+, although both could be observed after the addition of Mg2+. The sperm heads did not show fluorescence when attached to the surface of an egg previously microinjected with mithramycin A in Mg-free seawater, indicating that there was no connection between the sperm and the egg. Therefore, occurrence of fertilisation potential must be a post-fusional event. These results suggest that Mg2+are indispensable for fusion between the sperm acrosomal membrane and the egg plasma membrane.
A unique expression pattern for a sperm membrane protein during sea urchin spermatogenesis
Authors: Ward Rita D. , Mendoza Lisa M. , Moy Gary W. , Vacquier Victor D. , Nishioka David 
Published: September 2008

SummarySpecific mRNAs coding for a 63 kDa sperm membrane protein (63-SMP) were localised in Strongylocentrotus purpuratus testis sections using in situ hybridisation techniques. 35S-labelled antisense RNA probes transcribed from a 766 base pair fragment of the gene coding for the 63-SMP hybridised to all spermatogenic cells in the basal germinal epithelia of testicular acini, except the most peripherally located (least differentiated) spermatogonia. No hybridisation to the luminally located mature spermatozoa or somatic cells of the testis was observed. Using monoclonal antibody J17/30 and indirect immunofluorescence techniques, the 63-SMP was localised to the same subset of spermatogenic cells that contain the 63-SMP mRNA, suggesting that expression of this gene is transcriptionally controlled. In combination with previous studies on the expression of sperm histones and sperm bindin, these results show that multiple, perhaps sequential, classes of gene activity contribute to the differentiation of sea urchin sperm.
Association of cumulus–oocyte complexes with the intrafollicular levels of a blood proten inBubalus bubalis
Authors: Talevi R. , Bergamo P. , Sansone G. , Savarese A. , Venditti P. , Abrescia P. 
Published: September 2008

SummaryThe protein pattern of the follicular fluid (FF) and the ultrastructure of the inner cumulus–oocyte complex (COC) has been analysed in single antral follicles (n= 146) of buffaloB. Bubalisovaries. The protein population of FF was fractionated by SDS-PAGE; the resulting pattern was Coomassie stained and processed for densitometry. Comparartive analysis of sera and autologous FFs showed a marked difference in the level (measured as the percentage of total proteins) of one 21 kDa polypeptide band, called ‘L’. Concentration of L, which was mainly higher in the serum (2.05 ± 1.5%) than in the surrounding FF(0.98 ± 0.94%), fluctuated widely in fluids from the in the same ovary. On gel filtration of FF and SDS-PAGE of ther factions collected, the L polypeptide was found and eluted together with a 36 kDa polypeptide, called ‘H’, with an exclusion volume lower than that of albumin. The levels of both polypeptides in the eluted fractions were measured by gel densitometry and the same ratio H/L was found (2:1). These data suggest that H and L are subunits of a complex high-molecular-weight protein. The presence of L levels in male sera comparable to those detected in females indicates that this putative protein does not originate in the ovary but is transported from the blood. Moreover, a correlation between the increase in the percentage of Lf (calculated as %L in FF/%L in serum) and atresia was observed. COCs (n= 86) obtained during the collection of the single FF samples were processed for transmission electron microscopy. The ultrastructure of each COC was compared with the SDS-PAGE data of the associated FF. Healthy COCs were found to be related to very low levels of Lf (between 0 and 14% of those measured in serum). COCs with an early atretic ultrastructure undetectable at the dissection microscope, were associated with FFs having Lf levels between 24% and 60%; advanced atresia was associated with Lf values up to 70%. Finally, the acrosome reaction of buffalo precapacitated spermatozoain vitrowas monitored by adding one volume of FF with high (FF +; Lf = 80%) or undetectable (FF - ) values of Lf to the sperm suspension. It was found that 96.2% of spermatozoa treated with FF - showed a normal acrosome reaction, without any change in their motility pattern; spermatozoa treated with FF +, in contrast, exhibited poor motility, and only 66.4% of them underwent the acrosome reaction. The ionophore A23187, in a control experiment, resulted in lower percentages of acrosome reactions (38%). In conclusion, our results suggest that enhanced influx of L from serum into the follicle antrum causes an increase in the polypeptide level in FF. This might be due to a loss of selectivity in the blood-follicle barrier of early atretic follicles. The use of the L polypeptide as a biochemical marker for identifying the earlier stage of follicular atresia is proposed.
Localisation of potassium pumps inDrosophilaovarian follicles
Authors: Bohrmann Johannes , Heinrich Ulf-Rüdiger 
Published: September 2008

SummaryIt has been shown previously that, inDrosophilaoogenesis, potassium ions are important for bioelectric phenomena as well as for other physiological and development processes. In the present study we determined the spatial distribution and activity of the (Na+, K+)-pump and of ouabain-insensitive K+pumps in plasma membranes of vitellogenic ovarian follicles (stage 10). We used that light micorscopic anthroylouabain method as well as the cytochemical lead and cerium precipitation methods in combination with electron spectroscopic imaging (ESI) and elelctronm energy-loss spectroscopy (EELS). (Na+, K+)-ATPase activity was predominantly observed on the oolemma as well as on the membranes of the columnar follicle cells covering the oocyte, whereas on the membranes of the nurse cells and of the squamous follicle cells covering the nurse cells the activity was vary low. The highset activity of the (Na+K+)-pump was found at the anterior and posterior ends of the oocute, and this on the oolemma as well as on the membranes of the follicle cells located here. Strong activity of ouabain-insensitive K+-pumps was observed on most of the oolemma (except at the anterior of the oocyte) and on the membranes of some nurse cells located next to the oocyte, whereas less activity was found on the other nurse cell membranes and on the membranes of all follicle cells. The suitability of the differnet methods nurse cell membranes and on the membrances of all follicle cells. The suitability of th different methods used for determining the localisation as well as the activity of K+-pumps is discussed. We further discuss the nature of the ouabain-insensitive K+pumps and the relevance of the observed distribution of K+-pumps for K+uptake, extrafollicular ionic current flow intercelluar signalling and other developmental processes inDrosophilaoogenesis.
Nuclear Sm antigens in the sperm of different organisms
Authors: Delgadoa Fernando , Brito Monica , Concha Ilona I. , Schroeder Ricardo , Burzio Luis O. 
Published: September 2008

SummaryImmunoblot analysis of sperm protein from several species revealed the presence of polypeptides recognised by anti-Sm sera obtained from patients with systemic lupus erythematosus. Immunoreactive polypeptides in human, bull, mouse and rat sperm were identified as protein B', B and D as compared with the Sm polypeptides of HeLa cells. In the sperm of rooster, the teleost fishCyprinus carpioand the musselChoromytilus chorus, the immunoreactive polypeptide profile was more complex. To ascertain the sperm origin of the Sm antigens, immunolocalisation with anti-Sm serum was carried out. The results demonstrated that in all the specied studied staining was confinde to the sperm nucleus, confirming that some polypeptides of the small nuclear ribonnucleoprotein complex are present in the gamete.
Development of cortical contractility in theXenopus leavisoocyte mediated by reorganisation of the cortical cytoskeleton: a model
Authors: Ryabova Lyuba V. , Vassetzky Sergei G. , Capco David G. 
Published: September 2008

SummaryAs the amphibian oocyte becomes the fertilisation-competent egg an actin-myosin assembles in the cortex which provides for the cortical contraction that accompanies the fertilisation. A number of recent investigations provide data for development of a model detailing the structural changes which should accompany the development of this contractile network as well as the signalling mechanisms which regular assembly and contraction.
Second messenger signalling during hormone-inducedXenopusoocyte maturation
Authors: Cork R. John , Robinson Kenneth R. 
Published: September 2008

SummaryAlthough much information about such processes as cell cycle control, second messenger systems, protein kinases and steroid hormone action has been collected from studies ofXenopusoocyte maturation, we still have very little idea about how the steroid hormone, progesterone, signals the resumption of meiosis from the oocyte plasma membrane. In this review we re-examine the data on second messenger systems inXenopusoocytes and discuss some of the unresolved questions about hormone signal transduction during maturation. We outline some reasons for the contradictions in the literature and offer some suggestions for avenues of future research.
Differential accumulation of mRNA and interspersed RNA duringXenopusoogenesis and embrypgenesis
Authors: Liu Chengyu , Smith L. Dennis 
Published: September 2008

SummaryXenopusooctye cytoplasmic poly(A)+RNA has been shown to include two major complex classes: mRNA and interspersed RNA. the former is defined by its translatalility, the latter consists of non–translatable repeat–containing transcripts with unknown functions. In this study we compared the accumulation patterns of total mRNA and a subfamily of interspersed RNA, the XR family (McGrew&Richter, 1989, Dev. Biot. 134, 267–70)