Pkdrej, a member of the polycystin-1 gene family, is expressed only in the male germ line. Male mice that are homozygous for a targeted mutation in the Pkdrej allele (Pkdrej(tm/tm)) are fertile in unrestricted mating trials, but exhibit lower reproductive success when competing with wild-type males in sequential mating trials and in artificial insemination of mixed-sperm populations. Following ...

Introduction While conception rates following cervical insemination of synchronised ewes with fresh semen are generally around 60-70%, conception rates with frozen-thawed semen are unacceptably low (<20% generally). These poor conception rates following cervical insemination with frozen-thawed semen appear to stem from two inter-related factors which are additive in their negative impacts: (a) ...

I propose a mechanism by which viruses successfully infect new individuals, despite being immotile particles with no ability for directed movement. Within cells, viral particle movements are directed by motors and elements of the cytoskeleton, but how viruses cross extracellular barriers, like mucus, remains a mystery. I propose that viruses cross these barriers by hitch-hiking on bacteria or s...

Calcium (Ca(2+)) is an absolute requirement for a decisive sperm function event: the acrosome reaction (AR). Physiologically, sperm capacitation is a prerequisite for this specialized exocytosis and both events are intimately related. In an effort to separate capacitation from AR, we have been using a modified sperm incubation medium where Ca(2+) is replaced by Strontium (Sr(2+)). The aim of th...

Acrosomal assembly during spermatogenesis and acrosome reaction during sperm-oocyte interaction are unique events of vesicle synthesis, transport, and fusion leading to fertilization. SNARE complex formation is essential for membrane fusion, and vesicle-associated (v-) SNARE intertwines with target membrane (t-) SNARE to form a coiled coil that bridges two membranes and facilitates fusion. We d...

Axonemal dynein complexes are preassembled in the cytoplasm before their transport to cilia, but the mechanism of this process remains unclear. We now show that mice lacking Pih1d3, a PIH1 domain-containing protein, develop normally but manifest male sterility. Pih1d3(-/-) sperm were immotile and fragile, with the axoneme of the flagellum lacking outer dynein arms (ODAs) and inner dynein arms (...

The antigenic properties of mammalian spermatozoa have been a topic of interest since the work of Landsteiner before the turn of the century, and the last decade has seen a considerable resurgence of interest in this phenomenon. As many as 16 distinct antigens have been reported to exist on or in mammalian spermatozoa (reviewed by Piko, 1967 ; Metz, 1972) . Weil and Rodenburg (1962), and more r...

The cellular and molecular mechanisms regulating the reuptake of the testicular fluid supporting sperm exiting the testes in the bird are not known. The presence of aquaporins, proteins involved in transmembrane water transport, was investigated. Observations were limited to the ductuli efferentes, collecting ducts, and ductus epididymis. Interestingly all of these ducts were positive for aquap...

In flowering plants, pollen grains germinate to form pollen tubes that transport male gametes (sperm cells) to the egg cell in the embryo sac during sexual reproduction. Pollen tube biology is complex, presenting parallels with axon guidance and moving cell systems in animals. Pollen tube cells elongate on an active extracellular matrix in the style, ultimately guided by stylar and embryo sac s...