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  • 1
    Electronic Resource
    Electronic Resource
    Galactosyltransferase activity is restricted to the plasma membranes of equine and bovine sperm (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 28 (1991), S. 74-78 
    Details
    ISSN: 1040-452X
    Keywords: Galactosyltransferase ; Sperm-egg binding ; Fertilization ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: β1, 4-Galactosyltransferase (GalTase) is localized to the plasma membrane of mouse sperm, in which it mediates the binding of sperm to glycoconjugate residues in the egg zona pellucida. In this study, the presence and subcellular distribution of sperm GalTase were determined in two other mammalian species that yield sufficient sperm for subecellular fractionation. Equine and bovine semen were collected, and the plasma membranes (PM), outer acrosomal membranes (OAM), and inner acrosomal membranes (IAM) were sequentially removed. The purities of the isolated membrane preparations were determined by transmission electron microscopy and found to be ≥90%, 96%, and 98% for equine PM, OAM, and IAM, respectively, and ≥80%, 94%, and 97% for bovine PM, OAM, and IAM, respectively. GalTase activity was assayed under optimal conditions in all membrane preparations and was preferentially localized to the isolated PM both in equine and in bovine spermatozoa. The selective localization of GalTase to the sperm PM in two other species suggest that it may serve as a generalized gamete receptor during initial sperm-egg binding in mammals.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080280112
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  • 2
    Electronic Resource
    Electronic Resource
    Equine oocyte in vitro maturation: Influences of sera, time, and hormones (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 30 (1991), S. 360-368 
    Details
    ISSN: 1040-452X
    Keywords: Luteinizing hormone ; Equine chorionic gonadotropin ; Oocyte ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Objectives of the present research were to determine the influences of types of media, sera, time and hormones on equine oocyte in vitro maturation (IVM). The following types of media and sera were evaluated: Menezo's B2 medium (B2), modified Tissue Culture Medium 199 (TCM), Defined Medium (DM), fetal calf serum (FCS), mare serum collected on the first day of estrus (MS), and mare serum collected on the day of ovulation (MSO). Resultant oocyte maturation was compared with the control: DM with bovine serum albumin (BSA). Effect of culture time (0, 15, and 32 hr) and the following hormones on oocyte IVM were evaluated: none, bovine luteinizing hormone (bLH; 1, 10, 100 μg/ml), equine luteinizing hormone (eLH; 100 μg/ml), bovine follicle-stimulating hormone (FSH; 5 μg/ml), and equine chorionic gonadotropin (eCG; 1 and 100 IU/ml). Cumulus expansion in the media and sera experiments was 50% (DM with BSA), 80% (TCM, B2, and DM with MS or MSO), and 100% (FCS with any medium). The proportion of metaphase II (MII) oocytes was significantly (P 〈 0.05) increased by MS, MSO, and FCS as compared with the control (BSA). In vitro culture for either 15 or 32 hr significantly (P 〈 0.05) increased the percentage of MII oocytes as compared with 0 hr of culture. Cumulus expansion in the hormone experiments was 80% (none, bLH, and eLH), and 100% (eCG and FSH). Freshly prepared bLH significantly (P 〈 0.05) inhibited nuclear maturation of equine oocytes. In summary, 15 hr of culture was sufficient time for equine oocyte IVM and all combinations of medium, serum, and hormone addition were equally effective in achieving IVM except fresh bLH and DM with BSA.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080300411
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  • 3
    Electronic Resource
    Electronic Resource
    Fine structure of equine oocytes matured in vitro for 15 hours (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 37 (1994), S. 87-92 
    Details
    ISSN: 1040-452X
    Keywords: Equine ; IVM ; Oocyte ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Transmission electron microscopy (TEM) was used to evaluate the fine structure of equine oocytes cultured in vitro. Oocytes obtained by follicular aspiration were cultured for either zero or 15 hr. After treatment oocytes were processed either by light microsocopy (nuclear evaluation) or TEM (cytoplasmic evaluation). Those oocytes cultured for 15 hr were incubated in modified TCM 199 with 15% (v/v) mare serum (day of ovulation) at 39 ± 0.2°C. Evaluation using TEM revealed that cortical granules were present in all oocytes. However, zero-time oocytes contained few cortical granules, and these were scattered throughout the cytoplasm, whereas 15 hr oocytes contained numerous cortical granules primarily found in very close proximity to the oolemma. Further ultrastructural analysis of both groups revealed organelle structure similar to that previously described for in vivo matured equine oocytes. Evaluation of nucelar maturity (lacmoid stain) showed that 15 hr of culture resulted in significant numbers of oocytes at metaphase II (8/17; 47%). These data demonstrate that oocytes cultured for 15 hr in modified TCM 199 with 15% mare serum (day of ovulation) are mature with respect to nuclear configuration and cortical granule migration and, therefore, would be appropriate candidates for in vitro fertilization. © 1994 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080370112
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