Like other stifftail ducks, lake ducks are promiscuous and boisterous in their sexual activity. One explanation for the evolution of such a long penis might be selection for its competitive advantage — for instance, groups of drakes might display their everted penises to attract females. Success in sperm competition may also be a factor. The base of the lake-duck penis is covered with spines, y...

Unraveling animal life cycles and embryonic development is basic to understanding animal biology and often sheds light on phylogenetic relationships. A key group for understanding the evolution of the Metazoa is the early branching phylum Placozoa, which has attracted rapidly increasing attention. Despite over a hundred years of placozoan research the life cycle of this enigmatic phylum remains...

Fertilization is the process by which two terminally differentiated cells, the sperm and the egg, merge to form a totipotent cell, the zygote. This review addresses one of the culminating steps in getting sperm and egg together: the cell-cell interactions that allow the two gametes to fuse and create the zygote. Based on cell biological and genetic studies, major players include CD9 on the egg ...

Perhaps one of the most exciting and revolutionary scientific discoveries of the past 3 decades has been the development of in vitro fertilization (IVF) to treat human infertility. It is impossible to quantify its effect on numerous families since the first IVF birth in 1978 in Oldham, England (Steptoe and Edwards, 1978). With increasing clinical utilization of assisted reproductive technologie...

The images above were featured in the recent Biomedical Image Awards of the Wellcome Centre Medical Photographic Library in London, UK. They are part of a growing collection, now numbering over 150 000 images. In the photograph at top left, spinal nerves can be seen growing into the wing bud of a four-day chick embryo. Amid the long striations of the sea squirt heart at bottom left, the gap jun...

Abstract Background Spermatogonial stem cells (SSCs) in the testis are crucial for transferring genetic information to next generation. Successful transplantation of SSCs infertile men is an advanced therapeutic application reproductive biology research. Methods In this experimental research, both vitro and vivo characterization undifferentiated differentiated were performed by morphology—immun...

Since about 1880, the eggs and sperm of sea urchins have been used for the study of fertilization, the metabolic activation of development and gene regulatory mechanisms governing embryogenesis. Sea urchin gametes are a favorite material for observations of the process of fertilization in advanced high school, community college, and university biology laboratory courses. This article is a labor...

spermatozoa. Because spermatozoa are largely incapable of de novo gene transcription and contemporaneous protein translation, their biology is highly dependent on changes in their proteomic landscape mediated by myriad posttranslational modifications, including the acquisition or loss of entire proteins. Proteomic changes in the epididymis, for example, are central to our understanding of how s...

Micellar mannose nanoparticles were constructed from poly{styrene-co-[(maleic anhydride)-alt-styrene]} with fluorophores or quenchers doped into the hydrophobic inner cores, allowing the direct monitoring of multivalent lectin-glycan interactions. The mannose-displaying nanoparticles bind Con A and sperm surface lectins with high affinity, suggesting their broad utility for modulating protein-c...

Red light has been shown to increase sperm swimming speeds, but there is little characterization of its effect on DNA or swimming force. In this study 633nm laser light irradiation did not induce significant levels of oxidative DNA damage. OCIS codes: (000.1430) Biology and medicine, (350.4855) Optical tweezers or optical manipulation