Molecular Reproduction & Development Volume 78, Issue 8 cover image

Transmission electron micrograph of a sea urchin (Strongylocentrotus purpuratus) spermatozoon (purple) bound to the tip of an egg microvillus (yellow) by the bindin protein (diffuse purple), which was released during exocytosis of the sperm acrosomal vesicle. Egg microvilli are approximately 0.25 µm in diameter. More on observing these events on the cellular level in a classroom laboratory setting is presented by VD Vacquier (this issue).     

Molecular Reproduction & Development Volume 78, Issue 7 cover image

Ascidians are hermaphrodites, releasing sperm and eggs nearly simultaneously, but several species including the ascidian (prochodate) Ciona intestinalis are self‐sterile (self‐incompatible). In this species, the self‐incompatibility system is mediated by the vitelline coat ligand v‐Themis‐A/B and the sperm‐side receptor s‐Themis‐A/B. In this issue, it is described that a sperm GPIanchored protein CiUrabin in lipid rafts may play a key role in the primary binding of sperm to the vitelline coat. This image of a C. intestinalis egg was taken by Takako Saito.     

Molecular Reproduction & Development Volume 78, Issue 6 cover image

Artist's rendition of Xenopus sperm swimming in the jelly layers as they approach the egg surface. Burnett et al. (this issue) fi nd that water soluble components of this jelly layer directly interact with sperm, thereby initiating chemotactic motility towards the egg. Original art by Douglas Chandler.     

Molecular Reproduction & Development Volume 78, Issue 9 cover image

Failure of embryos to develop in vitro is often associated with increased cellular death or apoptosis. Apoptotic cell death signals involve the activation of cysteine proteases, namely caspases, which are produced as catalytically inactive zymogens and must undergo proteolytic processing (cleavage) for activation. Coutinho et al. (this issue) fi nd that cleaved (active) caspase 3 (CC3) was detected (green staining) in porcine embryos, and that elevated levels predict cell death and developmental delay. Blue staining indicates cell nuclei.     

Molecular Reproduction & Development Volume 79, Issue 12, December 2012 cover image

Spermatogenesis relies on an intimate relationship between developing spermatogenic cells and Sertoli cells. A surface‐expressed isoform of CEACAM2 (green) on elongating spermtids is used to maintain contact with Sertoli cells (red, tubulin, and their nuclei in blue, DAPI) shown here in stained frozen sections of mouse seminiferous tubules by Salaheldeen et al. (this issue).