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Several lines of evidence suggest that decapacitation of sperm occurs normally in the male reproductive tract, and as a result the acrosome is stabilized and the acrosome reaction is controlled. Since the defining experiments in 1951, where decapacitation was reversed in the female reproductive tract by capacitation, investigations have pursued the molecular events of this process. This review attempts to examine critically the older literature and compare that perspective with the current theories. The theories for decapacitation of sperm include the possible role of a peptide decapacitation factor, a glycoprotein-mediated steroid transfer to the sperm, masking of a galactosyl transferase by some macromolecule-containing carbohydrate, preclusion of calcium influx by a binding protein, and sperm interaction with the acrosome stabilizing factor. Although these theories are diverse, there are some unifying aspects. However, there remain some major unanswered questions. For example, although we point to some circumstantial evidence that infers a single decapacitation factor, this needs to be further substantiated. It is concluded that with the purification of a macromolecule involved in capacitation, specific proposals on the mechanism of capacitation, and new tools to evaluate the capacitation process, it is likely that another decade will not pass without emergence of a unifying molecular theory of sperm capacitation.

The three morphologically and functionally distinct jelly coat layers of Xenopus laevis eggs, J1, J2, and J3, were separated by manual dissection, solubilized with dithiothreitol, and physicochemically analyzed. The chemical composition of the three jelly layers varied from 37 to 48% protein and 63 to 52% carbohydrate. The carbohydrate consisted of hexosamines, galactose, and fucose. Some of the carbohydrate in each of the jelly layers was covalently linked to protein through O-glycosidic bonds as beta elimination of the carbohydrate moiety in the presence of alkali was observed. In agreement with a previous finding, covalently attached sulfate was localized within the innermost jelly coat layer, J1. Cellulose acetate electrophoresis at pH 8.0 resolved a total of nine macromolecular components from the three jelly coat layers differentially staining for protein and carbohydrate: J1 yielded two anodically migrating components; the middle layer J2 yielded two cathodically migrating macromolecular components; the outermost layer J3 contained five species, three anodic and two cathodic. Sodium dodecyl sulfate agarose gel electrophoresis analysis yielded nine unique species, six of which stained coincidently for protein and carbohydrate. Immunoelectrophoresis and Ouchterlony double diffusion analyses using antiserum to total jelly components resolved nine different antigenic species with cross-reactivity between one or two macromolecules in layers J1 and J3. Analytical sedimentation velocity centrifugation revealed eight distinct species all of which exhibited hypersharp schlieren patterns and whose s20,w values were highly concentration dependent. On the basis of these analyses, Xenopus laevis egg jelly layers are composed of at least 8-9 distinct macromolecular species. The majority of these macromolecules are uniquely associated with different jelly coat layers.

Secretory products of the oviduct provide part of the milieu for the critical events of fertilization and embryo development. Past work from this laboratory has indicated that three large sulfated glycoproteins can be isolated from rabbit oviductal fluid and are synthesized by oviductal epithelium incubated in vitro. These three glycoproteins are antigenically similar. This paper presents evidence for their localization within the oviductal tissue and their hormonal control of synthesis. Utilizing goat antiserum to these oviductal glycoproteins and the immunoglobulin-horseradish peroxidase bridge method, these macromolecules have been localized in the ampulla and isthmus of the oviduct. Ten days after ovariectomy an oviduct was removed for immunolocalization. The does were then given estradiol for the next 4 days and the second oviduct was removed. Oviducts treated with estradiol showed immunostaining of virtually all of the secretory granules within the secretory cells of the isthmus. While light level immunocytochemistry suggested the possibility of two populations of secretory granules within the ampulla because some of the granules did not show immunocytochemical staining, the more sensitive immunocytochemistry at the electron microscopic level showed staining of all granules of the ampulla and isthmus. Absorption of the antiserum with pure antigen prevented all staining. After ovariectomy and hormone withdrawal, most of the immunostaining was lost in the isthmus and virtually no staining in the ampulla was observed. Oviductal cell suspensions were made to evaluate incorporation of [35S] sulfate and [3H] leucine as a function of hormonal priming of the tissue. Estrogen-primed oviductal cells incorporated the sulfate and leucine into these specific glycoproteins.(ABSTRACT TRUNCATED AT 250 WORDS)