Reproduction Abstracts

Ca2+ signaling is crucial for regulation of sperm motility and [Ca2+]i oscillations may underlie ‘switching’ of sperm behaviors in human spermatozoa, which is believed to be important for sperm progression in the female tract. We have investigated the contribution of membrane potential (Vm) and the sperm Ca2+ channel CatSper to [Ca2+]i oscillations induced by progesterone (P4). Manipulation of Vm was p...

CatSper channels are expressed specifically in the principal piece of the sperm flagellum. In human sperm Catsper channel activation is polymodal and sensitive to increased pHi, progesterone and other agonists, potentially resulting in synergistic enhancement of Ca2+ influx and hyperactivation (1) We have investigated if the interaction of pHi with the CatSper agonist progesterone and 4-aminopyridine (4AP), a potent activator of hyperactivation in human sperm. [Ca<s...

Introduction: An ectopic pregnancy (EP) is defined as a conceptus implanting outside of the uterine cavity, most commonly in the Fallopian tube. It is a life-threatening gynaecological condition with limited treatment options. Large and unstable EP are managed by surgical excision. Smaller stable EP are medically managed with the chemotherapeutic drug methotrexate. Methotrexate has considerable side effects and a high treatment failure rate (~30%). There is an unmet medical ne...

Introduction: A high concentration of polyvinylpyrrolidone (PVP, average molecular weight 360 000) supplementation in culture medium exerts a positive influence on the growth and morphological organization of bovine oocyte–cumulus/granulosa cell complexes in a long-term culture. The objective of the present study was to determine the effect of PVP supplementation on the number of transzonal projections (TZPs) traversing the zona pellucida from cumulus cells to the oocyte....

In a previous study (Peres et al., 2008 Acta Scientiae Veterinariae 36 639), sunflower supplementation during 22 days improved conception rates by 20.4% in Timed AI programs in beef cows. We aimed to evaluate the effects of sunflower seed supplementation on circulating cholesterol (CHOL) and progesterone (P4) concentrations, and the conception rate of recipient beef heifers after timed embryo transfer (TET). Heifers were synchroniz...

Introduction: During implantation, uterine luminal epithelial cells (UECs) disassemble cell–cell and cell–matrix adhesions that contribute to the formation of an epithelial barrier, which is refractory to blastocyst implantation. These changes are critical for successful implantation. We have shown previously that claudin 7 is present in UECs and is lost prior to implantation in the rat. Epithelial cell adhesion molecule (EpCAM) is another protein frequently associat...

Introduction: Cryopreservation is possible for all stages of pre-implantation embryos. It has been reported that survival rate of blastocyst is comparably lower than other stages. There is a high volume of fluid in blastocoel cavity that can be a good ground for ice crystals formation, resulting in damage to the cell structure. In this study, the effects of artificial collapseand reduction of the fluid volume in blastocyst cavity before vitrification process on the survival ra...

Pigs provide outstanding models of human genetic diseases due to the striking similarities to human anatomy, physiology and genetics. Pig induced pluripotent stem cells (piPSCs) have been generated for several years but the cloning efficiency using unsynchronized piPSCs was extremely low. Here, we reported a method to produce diploid cloned embryos from piPSCs which were synchronized to metaphase. The piPSCs cell line was established using a drug-inducible system and exhibit s...

Female meiosis involves a highly asymmetrical division to form a large secondary oocyte and a small polar body. Polo-like kinase I (Plk1) is a serine/threonine kinase which is highly conserved from yeast to human and is a potent regulator of mitosis including cytokinesis. Plk1 is known to regulate myosin via the activation of RhoA which leads to the contraction of the cleavage furrow in mitotic cells. Indirect evidence has also shown that Plk1 may regulate Cdc42 activity throu...

Cyclin A, the first cyclin ever cloned, is thought to be an essential component of the cell-cycle engine. Mammalian cells encode two A-type cyclins, a testis-specific cyclin A1 and a ubiquitously expressed cyclin A2. Cyclin A2 is an essential mitotic CDK regulatory partner and is attributed with a wide range of effects early in the G2–M transition. Although its role in mitosis has been extensively investigated, research into the role of cyclin A2 in meiosis is lacking. In...