Optimizing Electrical Activation of Porcine Oocytes by Adjusting Pre‐ and Post‐Activation Mannitol Exposure Times

Modifying electrical activation conditions have been used to improve in vitro embryo production and development in pigs. However, there is insufficient information about correlations of porcine embryo development with oocyte pre‐ and post‐activation conditions. The purpose of this study was to compare the developmental rates of porcine oocytes subjected to different mannitol exposure times, either pre‐ or post‐electrical activation, and to elucidate the reason for the optimal mannitol exposure time. Mannitol exposure times around activation were adjusted as 0, 1, 2 or 3 min. Blastocyst development were checked on day 7. Exposure of oocytes to mannitol for 1 or 2 min before electrical activation produced significantly higher blastocyst rates than exposure for 0 or 3 min. There was no significant difference in blastocyst rates when activated oocytes were exposed to mannitol for 0, 1, 2 or 3 min after electrical activation. While exposure of oocytes to mannitol for 1 min pre‐ and 3 min post‐activation showed significantly higher blastocyst development than 0 min pre‐ and 0 min post‐activation. It also showed higher maintenance of normal oocyte morphology than exposure for 0 min pre‐ and 0 min post‐activation. In conclusion, exposure of oocytes to mannitol for 1 min pre‐ and 3 min post‐activation seems to be optimal for producing higher in vitro blastocyst development of porcine parthenogenetic embryos. The higher blastocyst development is correlated with higher maintenance of normal morphology in oocytes exposed to mannitol for 1 min pre‐ and 3 min post‐activation.     

Comparison of Conventional Freezing and Vitrification with Dimethylformamide and Ethylene Glycol for Cryopreservation of Ovine Embryos

The aim of this work was to evaluate the efficiency of the cryoprotectants dimethylformamide and ethylene glycol for cryopreservation of ovine embryos using vitrification and conventional freezing. The recovered embryos were distributed randomly in three treatment groups: Gr. 1: conventional freezing (n = 44), Gr. 2: vitrification with ethylene glycol (n = 39) and Gr. 3: vitrification with dimethylformamide (n = 38). Quality of fresh embryos in control group as well as of frozen and vitrified embryos was examined by three methodologies: staining with propidium iodide and Hoechst 33258 and evaluation under fluorescent microscopy, evaluation of re‐expansion and hatching rates after culture, and determination of apoptotic index with TUNEL technique. It was established that re‐expansion rate in all treatment groups was similar. In the same time, hatching rates were higher in Gr. 1 (40.5%) and Gr. 2 (35.3%) in comparison with Gr. 3 (15.5%, p < 0.05). The number of dead cells in vitrified embryos of Gr. 2 and Gr. 3 was higher (42.6 ± 26.2 and 63.2 ± 34.65, respectively) in comparison with Gr. 1 (conventional freezing, 10.1 ± 8.5, p < 0.05). Embryos vitrified with dimethylformamide included the same quality of apoptotic cells that Gr. 1 (conventional freezing) and fresh embryos. In conclusion, the dimethylformamide and ethylene glycol used as cryoprotectant to vitrify ovine embryos, in the concentrations and exposition time tested in this work, were not as efficient as the conventional freezing for cryopreservation of ovine embryos Thus, the conventional freezing with ethylene glycol was the most efficient method to cryopreserve ovine embryos in comparison with vitrification.     

KOI-126: a triply eclipsing hierarchical triple with two low-mass stars

The Kepler spacecraft has been monitoring the light from 150,000 stars in its primary quest to detect transiting exoplanets. Here, we report on the detection of an eclipsing stellar hierarchical triple, identified in the Kepler photometry. KOI-126 [A, (B, C)], is composed of a low-mass binary [masses M(B) = 0.2413 ± 0.0030 solar mass (M(⊙)), M(C) = 0.2127 ± 0.0026 M(⊙); radii R(B) = 0.2543 ± 0.0014 solar radius (R(⊙)), R(C) = 0.2318 ± 0.0013 R(⊙); orbital period P(1) = 1.76713 ± 0.00019 days] on an eccentric orbit about a third star (mass M(A) = 1.347 ± 0.032 M(⊙); radius R(A) = 2.0254 ± 0.0098 R(⊙); period of orbit around the low-mass binary P(2) = 33.9214 ± 0.0013 days; eccentricity of that orbit e(2) = 0.3043 ± 0.0024). The low-mass pair probe the poorly sampled fully convective stellar domain offering a crucial benchmark for theoretical stellar models.     

Nitrogen excretion in cockroaches: uric Acid is not a major product

Thin-layer chromatographic and enzymatic spectrophotometric analyses have failed to detect uric acid in fecal extracts from American cockroaches on specified diets. Uric acid appears in the excreta when it is a dietary constituent, although most of it is apparently absorbed and stored internally. Surprisingly, ammonia is a major excretory product.     

Aquaporin 9 is expressed in the epididymis of immature and mature pigs

Aquaporins (AQPs) are channel proteins that facilitate the transepithelial and bidirectional movement of water. AQP9 is an aquaporin that is expressed in the mammalian epididymis. This water transport contributes to epididymal sperm concentration. This study aimed to examine the morphology of epididymal epithelium in piglets and boars, as well as the expression and immunolocalization of AQP9. The piglets presented an epididymal epithelium in differentiation with principal, basal and apical cells. The cellular population of the epididymal epithelium in boars consisted of principal, basal, apical, clear and narrow cells. The migratory cells known as halo cells were observed in the epididymis of both piglets and boars. AQP9 expression presented differences between piglets and boars. Moderate intensity of AQP9 immunoreaction was observed in the apical border of the epididymal epithelium of the caput and cauda regions in the piglet epididymis. A moderate‐to‐intense reaction for AQP9 was observed in the nuclei of epithelial cells of the three epididymal regions in the boar epididymis. The region of the cauda epididymis showed reactivity for AQP9 also in the apical border of the epithelium. It is believed that the AQP9 is already functional in piglets at only 1 week of age and is more active, playing a pivotal role in the caput and cauda regions of the epididymis. Moreover, the intense AQP9 expression in the apical border of epithelial cells in the cauda region of the boar epididymis suggests a higher performance of AQP9 in this region, where sperm complete their maturation process, stored and concentrated.