bluuebunny/crossref_metadata_2025_split huggingface dataset:
Capacitation in vitro of bovine spermatozoa by oviduct epithelial cell monolayer conditioned medium
Authors: Chian Ri‐Cheng , Lapointe Serge , Sirard Marc‐André 
Published: February 2005

AbstractThe effect of the active capacitating factor secreted from oviduct epithelial cell monolayers (OECM) in different environments on in vitro fertilization was evaluated. Capacitation was determined as the ability of sperm to fertilize bovine oocytes in vitro. When the mTALP was supplemented with glucose during conditioning, the sperm penetration rate was significantly reduced (P ≤ 0.05) compared to the control (7% ± 1 vs. 30% ± 4). The percentages of sperm penetrated oocytes were higher following insemination in the OECM‐conditioned medium derived from the early stage (48% ± 7) of the estrous cycle than in the OECM‐conditioned medium derived from either mid (35% ± 2) or late stages (28% ± 3) of the estrous cycle. When the medium was supplemented with 0.1 or 0.5 μg/ml estradiol‐17β during medium conditioning, sperm penetration rates increased (P ≤ 0.05) compared to the control group (55% ± 4 vs. 40% ± 3 and 54% ± 2 vs. 41% ± 3, respectively). In addition, the percentages of penetrated oocytes significantly decreased (P ≤ 0.05) following insemination when the OECM‐conditioned medium was added to 0.01%, 0.05%, and 0.1% ethanol compared to the control (25% ± 4, 19% ± 2, 18% ± 3, and 45% ± 3, respectively). Sperm penetration rates significantly (P ≤ 0.01) decreased when the OECM‐conditioned medium was heated to 100°C for 5 min (10% ± 1 vs. 40% ± 3). These results suggest that the active capacitating factor was sereted by the OECM and that this capacitating factor in the OECM‐conditioned medium was inhibited by the presence of glucose. This factor was found to be heat‐sensitive and its action was affected by ethanol. The OECM derived from the three phases of the estrous cycle as well as the presence of estradiol‐17β influenced the capacity of the OECM to secrete this capacitating factor in Vitro. © 1995 wiley‐Liss, Inc.
Allelic polymorphism in the hamster oviductin gene is due to a variable number of mucin‐like tandem repeats
Authors: Paquette Yves , Merlen Yannick , Malette Brigitte , Bleau Gilles 
Published: February 2005

AbstractOviductins are high‐molecular‐weight glycoproteins specifically secreted by the oviduct. These proteins bind to the zona pellucida of the ovulated oocyte and remain associated with the embryo during its transit in the oviduct. They may be involved in fertilization and early embryonic development. In order to explore their putative biological function, the cDNA sequence corresponding to oviductin in the golden hamster was determined. We found that the deduced amino acid sequence of this heavily O‐glycosylated protein presents characteristics typical of mucins, including serine‐ or threonine‐rich tandem repeats. Analysis of several cDNA clones and of genomic DNA revealed the presence of a single copy gene with two frequent alleles differing in the number of repeats. Comparison with oviductin sequences from other mammals indicates a high degree of conservation amongst species, except for the repeat region which shows divergence, notably in the number of repeats. Based on its biochemical and genetic properties, hamster oviductin can now be classified as a secretory mucin. This concept provides a new insight in the elucidation of its biological role: oviductin could possibly provide the oviduct and the oocyte with a protective coating ensuring normal tubal function and embryonic development. © 1995 wiley‐Liss, Inc.
Leukemia inhibitory factor, LIF receptor, and gp130 in the mouse uterus during early pregnancy
Authors: Yang Zeng‐Ming , Le Su‐Ping , Chen Dong‐Bao , Cota Juan , Siero Valentina , Yasukawa Kiyoshi , Harper Michael J. K. 
Published: February 2005

AbstractLeukemia inhibitory factor (LIF) has been shown to play an important role in the implantation of mouse blastocysts. The present study was designed to investigate the changes of LIF protein, LIF receptor, and gp 130 in the mouse uterus during the early pregnancy. LIF protein and LIF receptor were at high levels in the mouse uterus near the time of ovulation and on day 4 of pregnancy. gp 130 was highest on days 3 and 4 of pregnancy. Both LIF receptor and gp 130 showed strong staining in the stroma of the day 5 uterus, at a time when LIF protein was low. The presence of LIF receptor and gp 130 in the luminal epithelium on day 4 and in the stroma on day 5 may indicate the site of the high affinity LIF receptor. The coexistence of a high level of LIF protein, LIF receptor, and gp 130 in the day 4 uterus is consistent with the previously observed high level of uterine LIF mRNA on the same day and the importance of LIF for the blastocyst implantation in mouse. © 1995 wiley‐Liss, Inc.
Effects of cumulus cells and follicle‐stimulating hormone during in vitro maturation on parthenogenetic activation of bovine oocytes
Authors: Chian R. C. , Sirard M. A. 
Published: February 2005

AbstractThe response to parthenogenetic activation (calcium ionophore A23187) of bovine oocytes after 30 hr of culture in different maturation conditions was evaluated. The activation rates of oocytes in response to 10 μ A23187 were similar (86% ± 4 vs. 89% ± 8) when the oocytes matured with or without cumulus cells were cultured in TCM‐199 + 10% fetal calf serum (maturation medium [MM]) alone. However, the activation rates were significantly lower in oocytes matured with than without cumulus cells (48% ± 10 vs. 79% ± 16; P < 0.05) when MM was supplemented with 0.5 μ/ml follicle‐stimulating hormone (FSH), 5.0 μg/ml luteinizing hormone (LH), and 1.0 μg/ml estradiol‐1β (E2). When oocytes with cumulus cells were cultured in different media, MM alone, MM + 0.5 μg/ml FSH, MM + 5.0 μg/ml LH, MM + 1.0 μg/ml E2, and MM + all three hormones, the percentages of activated oocytes were 91% ± 3, 52% ± 14, 83% ± 7, 83% ± 13, and 54% ± 7, respectively. Oocytes with or without cumulus cells during culture began to form a pronucleus 5 hr after activation (5% ± 1 and 7% ± 1, respectively). Finally, the proteins synthesized by oocytes matured with or without cumulus cells before (3 hr) and after (10 hr) activation was labeled with [35S]methionine for analysis. Before activation, a 47 kD protein complex was produced by cumulus cell‐intact oocytes. An active protein synthesis of 60 kD was characteristic for the oocytes with cumulus cells cultured in MM containing 0.5 μg/ml FSH. After activation, there was an appearance of proteins at 75 kD and 47 kD in the oocytes with cumulus cells but not in the oocytes without cumulus cells during the maturation period. These results indicate that bovine oocytes matured in vitro have different capacities for parthenogenetic activation depending on the presence or absence of cumulus cells and the presence of FSH in MM during culture. © 1995 wiley‐Liss, Inc.
Dynamics and organization of MAP kinase signal pathways
Authors: Errede Beverly , Cade Rebecca M. , Yashar Beverly M. , Kamada Yoshiaki , Levin David E. , Irie Kenji , Matsumoto Kunihiro 
Published: February 2005

AbstractIn the budding yeast, Saccharomyces cerevisiae, four separate but structurally related mitogen‐activated protein kinase (MAPK) activation pathways are known. The best understood of these regulates mating. Pheromone binding to receptor informs cells of the proximity of a mating partner and induces differentiation to a mating competent state. The MARK activation cascade mediating this signal is made up of Ste 11 (a MEK kinase [MEKK]), Ste7 (a MAPK/ERK kinase [MEK]), and the redundant MAPK‐related Fus3 and Kss1 enzymes. Another MAPK activation pathway is important for cell integrity and regulates cell wall construction. This cascade consists of Bck1 (a MEKK), the redundant Mkk1 and Mkk2 enzymes (MEKs), and Mpk1 (a MAPK). We exploited these two pathways to learn about the coordination and signal transmission fidelity of MAPK activation cascades.Two lines of evidence suggest that the activities of the mating and cell integrity pathways are coordinated during mating differentiation. First, cells deficient in Mpk1 are susceptible to lysis when they make a mating projection in response to pheromone. Second, Mpk1 activation during pheromone induction coincides with projection formation. The mechanism underlying this coordination is still unknown to us. Our working model is that projection formation generates a mobile second messenger for activation of the cell integrity pathway.Analysis of a STE7 mutation gave us some unanticipated but important insights into parameters important for fidelity of signal transmission. The Ste7 variant has a serine to proline substitution at position 368. Ste7‐P368 has higher basal activity than the wild‐type enzyme but still requires Ste 11 for its function. Additionally, the proline substitution enables the variant to transmit the signal from mammalian Raf expressed in yeast. This novel activity suggests that Ste7‐P368 is inherently more permissive than Ste7 in its interactions with MEKKs. Yet, Ste7‐P368 cross function in the cell integrity pathway occurs only when it is highly overproduced or when Ste5 is missing. This behavior suggests that Ste5, which has been proposed to be a tether for the kinases in the mating pathway, contributes to Ste7 specificity and fidelity of signal transmission. © 1995 wiley‐Liss, Inc.
Activation mechanism and function of the MAP kinase cascade
Authors: Gotoh Yukiko , Nishida Eisuke 
Published: February 2005

AbstractMAP kinase (MAPK) and its activator, MAP kinase kinase (MAPKK), are commonly activated by a variety of extracellular stimuli in mammalian cells and in the process of Xenopus occyte maturation. In order to investigate the function of the MAPK cascade in oocyte maturation, we produced an anti‐Xenopus MAPKK which specifically reacts with MAPKK in vitro. When this antibody was microinjected into immature oocytes, MAPK activation induced by progesterone was prevented. Surprisingly, H1 kinase activation and germinal vesicle breakdown were also inhibited in the oocytes injected with this antibody. These results suggest that the MAPK cascade plays an important role in the maturation promoting factor (MPF) activation during the oocyte maturation process. When this antibody together with Mos was micoinjected into Xenopus two‐cell embryos, the Mos‐induced metaphase arrest (CSF arrest) was prevented. Thus, the MAPK cascade may mediate CSF arrest. During Xenopus early embryogenesis, a low but significant level of MAPK remains active. Injection of mRNA encoding a constitutively active MAPKK resulted in mesoderm induction in animal cap explants. In addition, fibroblast growth‐factor (FGF)‐induced mesoderm induction was inhibited by expressing CL100 (a MAP kinase phosphatase) in animal cap explants. Thus the MAPK cascade may be involved in the mesoderm induction of Xenopus embryos. The activation pathways and roles of the MAPKK/MAPK cascade in various signaling processes will be discussed. © 1995 wiley‐Liss, Inc.
Observation of optical activity in polythiourethane obtained by the controlled cationic ring‐opening polymerization of chiral cyclic thiourethane derived from serine
Authors: Nagai Atsushi , Ochiai Bungo , Endo Takeshi 
Published: February 2005

AbstractThe secondary structure of an optically active polythiourethane [(CH2C*H(CO2Me)NHCOS)n] was evaluated with 1H NMR, IR, and circular dichroism (CD) spectroscopy. Hydrogen bonds between the carbonyl and NH groups in the thiourethane group constrained the main chain of the chiral polythiourethane precisely under the direction of chirality in the main chain, whereas the racemic polymer was also constrained but randomly. The secondary structure of the polythiourethane in CHCl3 changed noticeably in the presence or absence of trifluoroacetic acid, which eliminated constraining intramolecular hydrogen bonds. IR spectroscopy suggested that the secondary structure was almost identical in solid and solution states. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1554–1561, 2005
Theoretical studies of growth mechanism of small fullerene cage C24 (D6d)+
Authors: Lin Wen‐Hsin , Tu Chih‐Chiang , Lee Shyi‐Long 
Published: February 2005

AbstractThe ring‐collapse mechanism of C24 (D6d) has been analyzed using semiempirical AM1 and B3LYP/cc‐pVDZ methods. Based on the ring‐stacking/circumscribing model, two precursors are selected. Transition states and intermediates are located and energetics are computed. Before the stacking begins, the precursor and belt reach a suitable relative orientation accompanied by the release of a large amount of energy. It is observed that the reactions between the precursors and the belts are essentially endoergic in nature, whereas the reactions between the stable intermediates and the final belts are exoergic. The deformation energies (DE) and the bond lengths R of the precursors have been computed. The DE values suggest that there is a chance of the cleavage of the bicyclic precursors as the growth process proceeds toward the cage formation. In contrast, the monocyclic precursor is found to have lower deformation energies than the bicyclic precursor. Analysis of average bond length at different cages shows that a large window is formed and the system appears to follow a cascade‐type bond formation. Comparisons are made to our previous results on C28 growth. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Mass spectrometric detection of biotinylated peptides captured by avidin functional affinity electrophoresis
Authors: Lee Bao‐Shiang , Krisnanchettiar Sangeeth , Lateef Syed Salman , Gupta Shalini 
Published: February 2005

AbstractMatrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry was used to detect biotinylated peptides captured by avidin functional affinity electrophoresis (AFAEP). Peptide samples loaded onto AFAEP were heated with sodium dodecyl sulfate to ensure that the peptides are negatively charged, and thus migrate electrophoretically toward the cathode through the embedded avidin zone in the middle of the gel. To detect the biotinylated peptides, the band containing the avidin‐biotinylated peptide complexes was excised from a 7.5% w/v native polyacrylamide gel, and biotinylated peptides were extracted with aqueous 95% v/v formamide (pH 8.2), aqueous 6 M guanidine HCl (pH 1.5), or water, at temperatures from 4 to 95°C for periods from 5 min to 24 h. It was observed that all three solvents are capable of extracting biotinylated peptides and avidin from the gel, but the best results were obtained with aqueous 95% v/v formamide (pH 8.2) at 65°C for 20 min. However, some AFAEP‐captured biotinylated peptides are not stable and are extensively modified by formamide during extraction at too high a temperature or too long an extraction time. Copyright © 2005 John Wiley & Sons, Ltd.
Multitechnique characterization of thin films of immiscible polymer systems: PS–b‐PMMA diblock copolymers and PS–PMMA symmetric blends
Authors: Kailas L. , Nysten B. , Audinot J.‐N. , Migeon H.‐N. , Bertrand P. 
Published: February 2005

AbstractImmiscible polymer systems are known to form various kinds of phase‐separated structures capable of producing self‐assembled patterns at the surface. In this study, different surface characterization methods were utilized to study the surface morphology and composition produced after annealing thin polymer films. Two different SIMS techniques—static time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) and dynamic nano‐SIMS—were used, complemented by x‐ray photoelectron spectrometry (XPS) and atomic force microscopy (AFM). Thin films (spin‐coated onto silicon wafers) of polystyrene (PS)–poly(methyl methacrylate) (PMMA) symmetric blends and diblock copolymers of similar molecular weight were investigated.Surface enrichment by PS was found on all as‐cast samples. The samples were annealed at 160 °C for different time periods, after which the blend and the copolymer films exhibited opposite behaviour as seen by ToF‐SIMS and XPS. The annealed blend surface presented an increase in the PMMA concentration whereas that of copolymers showed a decrease in PMMA concentration compared with the as‐cast sample. For blends, the nano‐SIMS as well as AFM images revealed the formation of phase‐separated domains at the surface. The composition information obtained from ToF‐SIMS and XPS, as well as the surface mapping by nano‐SIMS and AFM, allowed us to conclude that PS formed phase separated droplet‐like domains on a thin PMMA matrix on annealing. The three‐dimensional nano‐SIMS images showed that the PS droplets were supported inside a rim of PMMA and that these droplets continued from the surface like columnar rods into the film until the substrate interface. In the case of annealed copolymer samples, the AFM images revealed topographical features resembling droplet‐like domains on the surface but there was no phase difference between the domains and the matrix. In the case of copolymers, owing to the covalent bonding between the blocks, complete phase separation was not possible. The three‐dimensional nano‐SIMS images showed domain structures in the form of striations inside the film, which were not continuous until the substrate interface. Information from the different techniques was required to gain an accurate view of the surface composition and topographical changes that have occurred under the annealing conditions. Copyright © 2005 John Wiley & Sons, Ltd.
Cortical GABAergic regulation of dopaminergic responses to psychological stress in the rat dorsolateral striatum
Authors: Matsumoto Machiko , Togashi Hiroko , Kaku Asako , Kanno Manabu , Tahara Kazue , Yoshioka Mitsuhiro 
Published: February 2005

AbstractThe present study was undertaken to examine the possible involvement of cortical γ‐aminobutyric acid (GABA) neuronal mechanisms in the regional differences of dopamine (DA) response to psychological stress: contextual fear conditioning (CFC) in the rat prefrontal cortex (PFC) and dorsolateral striatum (DLS). Rats that received five footshocks (shock intensity, 0.5 mA; shock duration, 2 sec) were subjected to CFC and dynamic changes in DA and GABA in both PFC and DLS were examined using dual‐probe microdialysis. Extracellular levels of DA in the PFC were enhanced during exposure to CFC, whereas the levels in the DLS were not affected by this stimulus. Extracellular levels of GABA in the PFC, but not in the DLS, were markedly enhanced by CFC. Freezing behavior observed during exposure to CFC was attenuated by the GABAA receptor antagonist bicuculline (10–3 M), which was perfused into the PFC. Intracortical application of bicuculline (10–3 M) furthermore caused sustained increases in DA levels in the DLS by CFC. These data suggest that cortical GABAA receptors contribute to modulation of DA release in the DLS in response to CFC. Thus, the GABAergic neuronal system in the PFC appears to play a key role in the regional differences of the DAergic response to psychological stress. Synapse 56:117–121, 2005. © 2005 Wiley‐Liss, Inc.
Ethylene-Induced Differential Growth of Petioles in Arabidopsis. Analyzing Natural Variation, Response Kinetics, and Regulation
Authors: Millenaar Frank F. , Cox Marjolein C.H. , van Berkel Yvonne E.M. de Jong , Welschen Rob A.M. , Pierik Ronald , Voesenek Laurentius A.J.C. , Peeters Anton J.M. 
Published: February 2005

Abstract
Plants can reorient their organs in response to changes in environmental conditions. In some species, ethylene can induce resource-directed growth by stimulating a more vertical orientation of the petioles (hyponasty) and enhanced elongation. In this study on Arabidopsis (Arabidopsis thaliana), we show significant natural variation in ethylene-induced petiole elongation and hyponastic growth. This hyponastic growth was rapidly induced and also reversible because the petioles returned to normal after ethylene withdrawal. To unravel the mechanisms behind the natural variation, two contrasting accessions in ethylene-induced hyponasty were studied in detail. Columbia-0 showed a strong hyponastic response to ethylene, whereas this response was almost absent in Landsberg erecta (Ler). To test whether Ler is capable of showing hyponastic growth at all, several signals were applied. From all the signals applied, only spectrally neutral shade (20 μmol m−2 s−1) could induce a strong hyponastic response in Ler. Therefore, Ler has the capacity for hyponastic growth. Furthermore, the lack of ethylene-induced hyponastic growth in Ler is not the result of already-saturating ethylene production rates or insensitivity to ethylene, as an ethylene-responsive gene was up-regulated upon ethylene treatment in the petioles. Therefore, we conclude that Ler is missing an essential component between the primary ethylene signal transduction chain and a downstream part of the hyponastic growth signal transduction pathway.
Impact of Reduced O-Acetylserine(thiol)lyase Isoform Contents on Potato Plant Metabolism
Authors: Riemenschneider Anja , Riedel Kerstin , Hoefgen Rainer , Papenbrock Jutta , Hesse Holger 
Published: February 2005

Abstract
Plant cysteine (Cys) synthesis can occur in three cellular compartments: the chloroplast, cytoplasm, and mitochondrion. Cys formation is catalyzed by the enzyme O-acetylserine(thiol)lyase (OASTL) using O-acetylserine (OAS) and sulfide as substrates. To unravel the function of different isoforms of OASTL in cellular metabolism, a transgenic approach was used to down-regulate specifically the plastidial and cytosolic isoforms in potato (Solanum tuberosum). This approach resulted in decreased RNA, protein, and enzymatic activity levels. Intriguingly, H2S-releasing capacity was also reduced in these lines. Unexpectedly, the thiol levels in the transgenic lines were, regardless of the selected OASTL isoform, significantly elevated. Furthermore, levels of metabolites such as serine, OAS, methionine, threonine, isoleucine, and lysine also increased in the investigated transgenic lines. This indicates that higher Cys levels might influence methionine synthesis and subsequently pathway-related amino acids. The increase of serine and OAS points to suboptimal Cys synthesis in transgenic plants. Taking these findings together, it can be assumed that excess OASTL activity regulates not only Cys de novo synthesis but also its homeostasis. A model for the regulation of Cys levels in plants is proposed.