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 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 3, March 2012 cover image

RNA interference provides a means of regulating gene expression by targeting genes for silencing in a sequence‐specific manner through the design of short hairpin RNAs (shRNAs). The development of such techniques for producing transgenic livestock that express shRNAs has tremendous potential for agriculture. Pictured here are cloned, transgenic bovine blastocysts established by Tessanne et al. (this issue) that express GFP in addition to an shRNA that targets the myostatin gene, a negative regulator of muscle growth.     

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 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 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 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 7, July 2012 cover image

Planarians can exist in both innately sexual and asexual modes, and the latter can be sexualized by a feeding method. The Dugesia ryukyuensis pictured were experimentally sexualized via feeding. They develop hermaphroditic sexual organs, copulate, and lay crossfertilized eggs. Three spheres are cocoons that contain several fertilized eggs. More can be learned about the cellular basis for this switching process in Nodono and Matsumoto (this issue).     

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 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.