The pollen tube of flowering plants undertakes a long journey to transport two sperm cells for double fertilization. New work on pollen tube guidance has identified an arabinogalactan-derived ovular factor that primes tubes to respond to female gametophyte-secreted attraction signals.

A distinctive Mn-2+-sensitive adenylate cyclase [ATP pyrophosphate-lyase(cyclizing), EC 4.6.1.1] system insensitive to fluoride has been found in rat seminiferous tubules and epididymal sperm. The development of this distinctive adenylate cyclase in testis was studied during spermatogenesis. It was first detectable in seminiferous tubules in immature rats at about the time of the first reductiv...

Protein recycling is important for maintaining homeostasis of the Golgi and its cisternae. The Vps54 (Scat) protein, a subunit of the GARP tethering complex, is a central factor in retrograde transport to the trans-Golgi. We found the scat(1) mutant to be male sterile in Drosophila with individualization problems occurring during spermatogenesis. Another typically observed phenotype was the abn...

Arginine vasopressin (VP) is neurohypophysial hormone has been implicated in stimulating contractile activity of the male reproductive tract in the testis. Higher levels of VP decrease sperm count and motility. However, very little is known about the involvement of VP in controlling mammalian reproductive process. The goal of this study was to confirm that effect of VP receptor (AVPR2) on sperm...

On terminally differentiated sperm cells, surface proteins are segregated into distinct surface domains that include the anterior and posterior head domains. We have analyzed the formation of the anterior and posterior head domains of guinea pig sperm in terms of both the timing of protein localization and the mechanism(s) responsible. On testicular sperm, the surface proteins PH-20, PH-30 and ...

During their epididymal maturation, stabilizing factors such as cholesterol sulfate are associated with the sperm plasma membrane. Cholesterol is sulfated in epididymal spermatozoa by the enzyme estrogen sulfotransferase. Because of its role in the efflux of sulfate conjugates formed intracellularly by sulfotransferases, the ATP-binding cassette membrane transporter G2 (ABCG2) might have a role...

The Physiology and Endocrinology Symposium titled “Sperm-Oviduct Interactions in Livestock and Poultry” was held at the joint annual meeting of the American Society of Animal Science, American Dairy Science Association, Poultry Science Association, Asociación Mexicana de Producción Animal, and Canadian Society of Animal Science, with partial sponsorship by the EAAP (European Federation of Anima...

Progesterone, a putative in vivo initiator of the human sperm acrosome reaction (AR), has previously been shown to act at the sperm plasma membrane to initiate the AR in vitro. Here, we have investigated whether bicarbonate (HCO3-) was required for the progesterone-initiated human AR and whether HCO3(-)-dependent cAMP activation might be involved. Capacitated human sperm were suspended in the p...

The oviduct occupies a unique position in mammalian reproduction as the site of sperm transport, the final maturation of sperm and egg, fertilization, and the initial development of the embryo. This dissertation examines the factors that control the number, distribution and physiological state of spermatozoa in the oviduct. The golden hamster (Mesocricetus auratus) was used as the animal model....