Molecular Reproduction & Development Volume 79, Issue 10, October 2012 cover image

Gonad development in some fish is controlled by fine‐tuned exposure to steroids. For example, genetically female (XX) medaka can be induced to form testes in the presence of cortisol. Kitano et al. (this issue) demonstrate that 17β‐estradiol can rescue this masculinization process, as demonstrated by this false‐colored image of the ovary‐filled gonad obtained from such a fish.     

Molecular Reproduction & Development Volume 79, Issue 6, June 2012 cover image

Maturation in bovine oocytes is triggered by a single surge of gonadotropins, i.e., luteinizing hormone (LH) and follicle‐stimulating hormone (FSH), which cause changes in the intraooplasmic concentrations of second messengers such as cyclic adenosine 3′,5′‐ monophosphate and Ca²+ through their activity on cumulus cells (see Silvestre et al., this issue). This time‐sequence shows a representative fluorescent intensity profile of the Ca²+ wave triggered in cumulus cells by the addition of FSH in an immature bovine cumulusoocyte complex loaded with the fluorescent Ca²+ indicator Fluo‐4 FF/AM. The top image shows the cumulus‐oocyte complex at the time of FSH addition, and the bottom image shows the same cumulus‐oocyte complex 162 sec after exposure; intermediate images were taken at 48, 66, 84, 108, 132 sec from the addition of FSH, respectively.     

Molecular Reproduction & Development Volume 79, Issue 5, May 2012 cover image

Buffaloes (Bubalus bubalis) constitute an important animal in the dairy economy of India and South Asian countries. Implementation of embryo‐related artifi cial reproductive technologies will facilitate planned improvement strategies for this species. Yet more needs to be understood about its embryonic development. Verma et al. (in this issue) contribute to this understanding by identifying the stage of embryonic genome activation.     

Molecular Reproduction & Development Volume 79, Issue 9, September 2012 cover image

Semen has a heterogeneous population of sperm with varying degrees of DNA damage. Increased sperm DNA fragmentation is a pathological trait observed in a large percentage of infertile men (Shamsi et al., this issue). Pictured here is the comet assay (background), which is used to assess DNA fragmentation in sperm populations from infertile men. It can distinguish individual sperm with intact DNA (circular halos) from those with DNA damage (smaller halo in the comet head, with most of the DNA migrating into the comet tail). A scanning electron micrograph of a human sperm (image courtesy of Judith Lyons, www.judithlyons.co.uk ) and DNA double helix and are shown in relief.     

Molecular Reproduction & Development Volume 79, Issue 2, February 2012 cover image

Reflected image assembly of a median sagittal section of the epididymal channel during the mating period in the seasonal breeder Podarcis sicula (lizard). The main channel lumen is filled with spermatozoa and secretory granules during this period. Details about the regionalization and specialization of this organ are detailed in Verderame et al. (this issue).     

Molecular Reproduction & Development Volume 79, Issue 4, April 2012 cover image

In sea urchins, a soluble coat of egg jelly induces morphological and physiological changes in spermatozoa. This colorized scanning electron micrograph is a snapshot of such activated sperm. In this issue, Kazama et al. identify the reactive oxygen species that are generated by this process and that may influence sperm behavior.     

Molecular Reproduction & Development Volume 79, Issue 11, November 2012 cover image

Image of mouse egg after intracytoplasmic sperm injection. A filamentous actin cap (red) has formed over the decondensing sperm head (DNA in blue), displacing cortical granules (green) from that region. Some cortical granules have undergone exocytosis in response to sperm‐induced calcium release, as detailed in Miao and Williams (this issue).     

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).     

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 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 78, Issue 12 cover image

Signal transduction across plasma membrane is prerequisite for activation of sperm motility and sperm chemotaxis at fertilization. An oscillatory increase in intracellular calcium occurs upon activation of tunicate sperm (shown in false color in the foreground, clockwise displaying later time points; starting at 11:00). Zhu and Inaba (this issue) report that lipid rafts are essential for these calcium dynamics and for subsequent activation of adenylyl cyclase. Background image is of a single tunicate, Ciona intestinalis.