Archive for the ‘Cell’ Category - Part 4

Dynamics of Carbohydrate Affinities at the Cell Surface: MATERIALS AND METHODS(2)

The tetramethylbenzidine was from Merck (Darmstadt, Germany). Chlortetracycline (CTC), Toluidine Blue, Л-a-benzoyl-L-argi-nine-p-nitroanilide (4.0 mM), cartilage chondroitin 4-sulphate, heparin-al-bumin-biotin (heparin-BSA-biotin), inositol, D( + )-mannose, maltose, mannan (from Saccharomyces ceravisiae), D( + )-glucose, fucose, fucoi-dan, 1-O-methyl-a-D-glycopyranoside and bovine serum albumin (BSA) as well as all other chemicals were from Sigma (St. Louis, MO) if not indicated otherwise. […]

Dynamics of Carbohydrate Affinities at the Cell Surface: MATERIALS AND METHODS(1)

Chemicals and Media Polyacrylamide-biotin (PAA-biotin) as well as a-L-fucose-polyacryl-amide-biotin (fucose-PAA-biotin) and LewisA-polyacrylamide-biotin (LeA-PAA-biotin) were obtained from Glycotech Corporation (Moscow, Russia). Both biotinylated probes consist of 20 mol% carbohydrate, 5 mol% biotin, and 75 mol% acrylamide, which equals the conjugation of four carbohydrate moieties and one biotin moiety to one polyacrylamide molecule. Neutravidin horseradish peroxidase conjugated […]

Dynamics of Carbohydrate Affinities at the Cell Surface: INTRODUCTION(5)

Due to technical limitations, it is difficult to follow this process in situ. In this study, we used biotinylated carbohydrate probes to detect carbohydrate affinity of sperm cells before and after capacitation in vitro. To this end, the specific oviduct-binding area of the sperm surface (the apical sperm head plasma membrane) with the carbohydrate binding […]

Dynamics of Carbohydrate Affinities at the Cell Surface: INTRODUCTION(4)

Despite the importance of follicular fluid for IVF and for in vitro sperm capacitation, the effects on carbohydrate-binding affinities of the sperm cell (and thus its affinity for the oviduct epithelial cells) have still to be elucidated. It should be noted that sperm capacitation normally occurs in the female genital tract, but for IVF, sperm […]

Dynamics of Carbohydrate Affinities at the Cell Surface: INTRODUCTION(3)

Although initial attempts have been made to characterize molecules involved in sperm-oviduct binding, still very little is known about the mechanisms involved in sperm release after ovulation. Hormonal changes at the time of ovulation are likely to affect sperm release. Preliminary data suggested that these changes induce secretory activity in the oviduct, most predominantly in […]

Dynamics of Carbohydrate Affinities at the Cell Surface: INTRODUCTION(2)

The sperm cells contain lectin-like molecules on their cellular surface with affinities for certain carbohydrate moieties on the apical surface of oviduct epithelial cells. Indirectly, these interactions can be studied by the use of competitive carbohydrate-binding inhibition assays. For instance, fetuin and sialic acid specifically block binding of the hamster sperm to the oviduct epithelium, […]

Dynamics of Carbohydrate Affinities at the Cell Surface: INTRODUCTION(1)

Sperm cells are stored in the oviduct of mammalian species during estrus. Bovine sperm cells actively attach to ciliated epithelial cells with the apical part of the sperm head surface. Sperm cells remain attached until the time of ovulation, when, under not-yet-characterized conditions, they will be released and are capable of fertilizing the oocyte (capacitated). […]

Cloned Mice: DISCUSSION(4)

Although the efficacy of IE and the resulting cytoplast developmental competence in different strains of mouse oocytes were not compared directly, a slight improvement in cleavage and blastocyst development and a live offspring were obtained using B6CBAF1 oocytes. In this strain, ethanol-induced meiotic progression was initially delayed, so that by 15 min pa, 97% of […]

Cloned Mice: DISCUSSION(3)

A confounding variable in our comparison of cytoplast types was the use of ethanol versus SrCl2 for activation. Ethanol was used in our study because of its apparent success in yielding cloned mice from cumulus cells following IE of B6D2F1 oocytes. Activation using ethanol has also used successful in goat cloning by somatic cell nuclear […]

Cloned Mice: DISCUSSION(2)

Given the relatively low rate of IE, oocytes whose chromatin would have only been incompletely compartmentalized in PBs were also used in the creation of cytoplasts for nuclear transfer experiments. Thus, the relative developmental competence of both oocyte types was not considered. In vitro development of embryos cloned by transfer of ES cell nuclei into […]

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