Fertilization Mechanisms in Man and Mammals

Pre-loading of mouse oocytes with DNA-specific fluorochrome (Hoechst 33342) permits rapid detection of sperm-oocyte fusion

“…The non-toxic properties of H-33342 depend on cell type and dye concentration, with 1-10 pg H-33342/ml being the typical concentration range used to obtain non-toxic effects in a variety of cell types. However, we found that, with mature mouse oocytes, a concentration of 10 pg H-33342/ml produced detrimental effects, while the viability of oocytes stained with 1 pg H-33342/ml was not significantly different from controls (Table 1 Gwatkin, 1977). During staining, the fluorochrome not only enters the oocyte cytoplasm and nucleus but also becomes trapped within the perivitelline space.…”

Synthesis of zona pellucida proteins by denuded and follicle-enclosed mouse oocytes during culture in vitro

“…It has been known for some time, primarily on the basis of its staining properties, that the zona pellucida contains protein and carbohydrate (3,5), and our recent work demonstrated that the zona pellucida is composed of three different protein species, which we have designated ZP1, ZP2, and ZP3. Having identified the proteins that compose the zona pellucida has permitted us to examine the site of synthesis of these proteins during follicular development.…”

“…The zona pellucida is laid down during growth of the ovarian follicle, remains throughout preimplantation development, and is finally shed as the blastocyst readies for implantation (1)(2)(3). Several lines of evidence suggest that the zona pellucida possesses a receptor for sperm, that it acts as a barrier to further sperm penetration after fertilization, and that its presence is necessary for normal early development in vivo (3)(4)(5). In certain respects the zona pellucida is morphologically and functionally analogous to the vitelline envelope that surrounds oocytes of lower animal species (6,7).…”

ATP‐dependent Ca2+ transport in vesicles isolated from the bile canalicular region of the hepatocyte plasma membrane

“…The high-affinity Ca2'-ATPase is coupled to Ca2 + transport, is calmodulinin'sensitive, sensitive to vanadate under appropriate experimental conditions and is strongly inhibited by La3 ' . Intracellular Ca2+ is essential in the regulation of a large number of cell functions, among them cell motility [I], egg activation [2], muscle contraction [3], neurotransmission [4], secretion [5], and cell proliferation [6]. In spite of the continuous passive entry of external Ca2+, cells maintain the intracellular concentration (0.1 -1 .O pM) three to four orders of magnitude lower than in the extracellular medium (1 -3 mM).…”