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Hiroaki Funahashi - One of the best experts on this subject based on the ideXlab platform.

  • 224 SILDENAFIL ACCELERATES SPERM PENETRATION OF PORCINE OOCYTES IN A Chemically Defined Medium
    Reproduction Fertility and Development, 2013
    Co-Authors: Hiroaki Funahashi
    Abstract:

    Sperm capacitation, a cyclic-adenosine monophosphate-dependent phenomenon, is an important initiation step for penetration into oocytes. In porcine IVF, the use of caffeine, as a nonspecific phosphodiesterase (PDE) inhibitor, is common to accelerate sperm capacitation and penetration. The objective of this study was to examine the effects of PDE inhibitors (cilostamide, rolipram, and sildenafil as PDE type 3-, type 4-, and type 5-specific inhibitors, respectively) on the capacitation of boar sperm and the penetration into porcine oocytes in the absence of caffeine and other capacitation inducers in a Chemically Defined Medium. After washing sperm samples collected from an ejaculated sperm-rich fraction of different individual Berkshires, the sperm were resuspended in capacitation inducer-free (theophylline- and adenosine-free) PGM-tac4 (mPGM-tac) at 5 × 105 cells mL–1. The suspension was cultured in mPGM-tac nonsupplemented or supplemented with 2.5 mM cilostamide, rolipram, or sildenafil for 90 min at 39°C in an atmosphere of 5% CO2 in air, and then the capacitation status was assessed by chlortetracycline fluorescence assay. Other sperm suspensions were used to co-culture with denuded in vitro-matured oocytes in the same Medium for 8 h in an atmosphere of 5% CO2 in air and fixed, and sperm penetration was then examined. Statistical analyses of results from 4 replicated trials were performed by ANOVA with a Bonferroni-Dunn post hoc test (significance, P < 0.05). In our result from the chlortetracycline fluorescence assay, although the incidence of intact sperm was significantly reduced in the presence of rolipram (54.3%) and sildenafil (52.7%) as compared with controls (66.7%), there were no differences in capacitated sperm among experimental groups (24.3 to 34.3%). The incidence of acrosome-reacted sperm was higher in the presence of cilostamide (17.3%) than in the others (9.0 to 13.0%). High sperm penetration was observed only in the presence of sildenafil (76.6%) as compared with the control (0%) or the presence of rolipram (4.4%) or cilostamide (1.8%). These results demonstrate that inhibition of PDE type 5, but not PDE type 3 and type 4, significantly accelerates the penetration of boar sperm into the oocytes in a capacitation inducer-free Chemically Defined Medium, whereas inhibition of PDE type 3 may induce an acrosome reaction.

  • effect of glucose and pyruvate on nuclear and cytoplasmic maturation of porcine oocytes in a Chemically Defined Medium
    Theriogenology, 2008
    Co-Authors: Hiroaki Funahashi, Takayuki Koike, Ryoko Sakai
    Abstract:

    The objective was to examine potential roles of glucose and pyruvate in nuclear and cytoplasmic maturation of porcine oocytes. Oocyte-cumulus complexes (OCC), derived from 3 to 6 mm follicles, were cultured in a Chemically Defined Medium (pyruvate-free mNCSU37-PVA), with or without 5.55 mM glucose, during in vitro maturation (IVM); in the absence of glucose, germinal vesicle breakdown (GVBD) and nuclear maturation were prevented (P = 10 mu M 6-AN and >= 10 nM DPI) inhibited resumption of meiosis (P

William B. Mcgill - One of the best experts on this subject based on the ideXlab platform.

  • Azospirillum brasilense produces gibberellin in pure culture on Chemically-Defined Medium and in co-culture on straw
    Soil Biology & Biochemistry, 1992
    Co-Authors: R.a. Janzen, Johan F Dormaar, Stewart B. Rood, William B. Mcgill
    Abstract:

    Abstract Rhizobacteria have been shown to produce gibberellin (GA)-like substances, but this evidence has been obtained primarily from analysis by bioassay, usually on Chemically-Defined Medium, and always in systems containing a single microorganism. We examined, by capillary gas chromatography-mass spectrometry, the production of GAs by Azospirillum brasilense (1) in pure culture on Chemically-Defined Medium and (2) in co-culture with Trichoderma harzianum, a fungus which degrades cellulose and controls some bacterial and fungal phytopathogens, in a barley straw decomposition culture. Pure cultures of Azospirillum brasilense contained Ga3 >iso-Ga3 >GA1, but no precursors thereto were detected. In the Azospirillum + Trichoderma straw culture 0.5 ng Ga1 g−1 straw was measured. This is direct, analytical evidence that Azospirillum brasilense produces GA in the presence of complex biochemicals and another microorganism.

R.a. Janzen - One of the best experts on this subject based on the ideXlab platform.

  • Azospirillum brasilense produces gibberellin in pure culture on Chemically-Defined Medium and in co-culture on straw
    Soil Biology & Biochemistry, 1992
    Co-Authors: R.a. Janzen, Johan F Dormaar, Stewart B. Rood, William B. Mcgill
    Abstract:

    Abstract Rhizobacteria have been shown to produce gibberellin (GA)-like substances, but this evidence has been obtained primarily from analysis by bioassay, usually on Chemically-Defined Medium, and always in systems containing a single microorganism. We examined, by capillary gas chromatography-mass spectrometry, the production of GAs by Azospirillum brasilense (1) in pure culture on Chemically-Defined Medium and (2) in co-culture with Trichoderma harzianum, a fungus which degrades cellulose and controls some bacterial and fungal phytopathogens, in a barley straw decomposition culture. Pure cultures of Azospirillum brasilense contained Ga3 >iso-Ga3 >GA1, but no precursors thereto were detected. In the Azospirillum + Trichoderma straw culture 0.5 ng Ga1 g−1 straw was measured. This is direct, analytical evidence that Azospirillum brasilense produces GA in the presence of complex biochemicals and another microorganism.

Stewart B. Rood - One of the best experts on this subject based on the ideXlab platform.

  • Azospirillum brasilense produces gibberellin in pure culture on Chemically-Defined Medium and in co-culture on straw
    Soil Biology & Biochemistry, 1992
    Co-Authors: R.a. Janzen, Johan F Dormaar, Stewart B. Rood, William B. Mcgill
    Abstract:

    Abstract Rhizobacteria have been shown to produce gibberellin (GA)-like substances, but this evidence has been obtained primarily from analysis by bioassay, usually on Chemically-Defined Medium, and always in systems containing a single microorganism. We examined, by capillary gas chromatography-mass spectrometry, the production of GAs by Azospirillum brasilense (1) in pure culture on Chemically-Defined Medium and (2) in co-culture with Trichoderma harzianum, a fungus which degrades cellulose and controls some bacterial and fungal phytopathogens, in a barley straw decomposition culture. Pure cultures of Azospirillum brasilense contained Ga3 >iso-Ga3 >GA1, but no precursors thereto were detected. In the Azospirillum + Trichoderma straw culture 0.5 ng Ga1 g−1 straw was measured. This is direct, analytical evidence that Azospirillum brasilense produces GA in the presence of complex biochemicals and another microorganism.

Johan F Dormaar - One of the best experts on this subject based on the ideXlab platform.

  • Azospirillum brasilense produces gibberellin in pure culture on Chemically-Defined Medium and in co-culture on straw
    Soil Biology & Biochemistry, 1992
    Co-Authors: R.a. Janzen, Johan F Dormaar, Stewart B. Rood, William B. Mcgill
    Abstract:

    Abstract Rhizobacteria have been shown to produce gibberellin (GA)-like substances, but this evidence has been obtained primarily from analysis by bioassay, usually on Chemically-Defined Medium, and always in systems containing a single microorganism. We examined, by capillary gas chromatography-mass spectrometry, the production of GAs by Azospirillum brasilense (1) in pure culture on Chemically-Defined Medium and (2) in co-culture with Trichoderma harzianum, a fungus which degrades cellulose and controls some bacterial and fungal phytopathogens, in a barley straw decomposition culture. Pure cultures of Azospirillum brasilense contained Ga3 >iso-Ga3 >GA1, but no precursors thereto were detected. In the Azospirillum + Trichoderma straw culture 0.5 ng Ga1 g−1 straw was measured. This is direct, analytical evidence that Azospirillum brasilense produces GA in the presence of complex biochemicals and another microorganism.