Chromatin and cytoplasmic characteristics of equine oocytes recovered by transvaginal ultrasound-guided follicle aspiration are influenced by the developmental stage of their follicle of origin.

Dynamic follicular changes occur during the equine estrus cycle, but little is known about their impact on the properties of recovered oocytes. The aim of this study was to characterize the cytoplasmic and chromatin status of equine oocytes in relation to the time of recovery during the follicle wave. Transvaginal ultrasound-guided follicle aspiration was performed two times in relation to the follicle wave: estrus-subordinate, from the subordinate follicles of mares in estrus, 24 hours after human chorionic gonadotropin stimulation of a dominant preovulatory follicle, and new-wave, from the follicles of the subsequent induced follicular wave, at the time of dominant follicle divergence (largest follicle 23 mm diameter).

Sperm migration in pigs after deep intrauterine and intraperitoneal insemination.

Deep intrauterine insemination in pigs allows sperm deposition only into one uterine horn, but bilateral fertilization of oocytes occurs. How the sperm reach the contralateral oviduct remains disputable. The aim of this experiment was to study possible transperitoneal and/or transuterine sperm migration ways.

Occurrence of polyovular follicles in mouse lines selected for high fecundity.

The aim of this study was to evaluate the prevalence of follicles with more than one oocyte (polyovular follicles, POFs) in mouse lines selected for high fecundity. The ovaries of 18 mice, 6 each from 3 different lines, were examined to evaluate the number of POFs and the follicular histology. Polyovular follicles were observed in the two high fecundity breeds, FL1 and FL2, as well as in the unselected control line, DUKsi.

Meiotic progression, mitochondrial features and fertilisation characteristics of porcine oocytes with different G6PDH activities.

The aim of the present study was to investigate the developmental competence, mitochondrial characteristics and chromatin status of immature follicular porcine oocytes selected for their glucose-6-phosphate dehydrogenase (G6PDH) activity by brilliant cresyl blue (BCB) staining. In Experiment 1, the oocyte parameters were determined in parallel right after BCB staining (T(0)), after 22 h of in vitro maturation (IVM) (T(22)) and after 44 h of IVM (T(44)) (n = 496). BCB-stained oocytes (BCB+) at T(0) were characterised by fibrillated chromatin filaments in their germinal vesicles (GV) and diakinesis stages whereas unstained (BCB-) oocytes at T(0) contained in their GV mainly condensed stages of chromatin (P < 0.

Regulation of cap-dependent translation initiation in the early stage porcine parthenotes.

The binding of mRNAs to ribosomes is mediated by the protein complex eIF4F in conjunction with eIF4B (eukaryotic initiation factor 4F and 4B). EIF4F is a three subunit complex consisting of eIF4A (RNA helicase), eIF4E (mRNA cap binding protein), and eIF4G (bridging protein). The crucial role is played by eIF4E, which directly binds the 5'-cap structure of the mRNA and facilitates the recruitment to the mRNA of other translation factors and the 40S ribosomal subunit.

Molecular and subcellular characterisation of oocytes screened for their developmental competence based on glucose-6-phosphate dehydrogenase activity.

Oocyte selection based on glucose-6-phosphate dehydrogenase (G6PDH) activity has been successfully used to differentiate between competent and incompetent bovine oocytes. However, the intrinsic molecular and subcellular characteristics of these oocytes have not yet been investigated. Here, we aim to identify molecular and functional markers associated with oocyte developmental potential when selected based on G6PDH activity.

Alterations in transcript abundance of bovine oocytes recovered at growth and dominance phases of the first follicular wave.

Background: Oocyte developmental competence is highly affected by the phase of ovarian follicular wave. Previous studies have shown that oocytes from subordinate follicles recovered at growth phase (day 3 after estrus) are developmentally more competent than those recovered at dominance phase (day 7 after estrus). However, the molecular mechanisms associated with these differences are not well elucidated.

Effect of recombinant bovine somatotropin (rbST) on cytoplasmic maturation of bovine oocytes and their developmental competence in vitro.

The objectives of this study were to evaluate the effects of recombinant bovine somatotropin (rbST) on the nuclear and cytoplasmic maturation of bovine oocytes and their further developmental competence to blastocysts in vitro. We analyzed the mitochondrial activity and concentration of intracellular stored calcium ([Ca(2+)](is)) in matured oocytes and the morphology and chromatin status of produced embryos after in vitro fertilization. Cumulus-oocyte complexes were incubated in TCM 199 containing 10% fetal calf serum (control medium 1: CM 1) or 10% estrus cow serum (control medium 2: CM 2).

Experimental evidence for the influence of cumulus-oocyte-complexes on sperm release from the porcine oviductal sperm reservoir.

In the pig, a temporal relationship is suggested between sperm release from the sperm reservoir (SR) and ovulation, but the mechanism(s) is still under discussion. In two experiments, the influence of transferred ova on the release of SR-spermatozoa at ovulation and the effect of supplementation with non-sulfated glycosaminoglycan hyaluronan (HA) on embryo development and the number of accessory spermatozoa, respectively, were examined. PMSG/hCG primed ovectomized gilts that had previously received endoscopic low-dose insemination into the cranial uterine horn were used as an experimental model.

Developmental competence of HMC(TM) derived bovine cloned embryos obtained from somatic cell nuclear transfer of adult fibroblasts and granulosa cells.

To enable us to handle a large number of oocytes at a given time and to have an increased throughput of cloned embryos, we attempted the Handmade cloning (HMC) technique, a zona-free method of bovine somatic cell nuclear transfer. Our objective was to study the developmental competence of the HMC derived embryos obtained using different types of somatic cells. A total of 6,874 cumulus-oocyte-complexes were used with either 7th or 11th passage fibroblasts (1st and 2nd groups, respectively), which were prepared from male animals, or granulosa cells (3rd group) as nuclei donors.

Comparison of follicular and oocyte development and reproductive hormone secretion during the ovulatory period in Hungarian native breed, Mangalica, and Landrace gilts.

Only a very small amount of physiological data is available about the low fertility (mean litter size is 5.7+/-0.8) of Hungarian native breed, Mangalica (M), sows.

Ovarian activity and oocyte development during follicular development in pigs at different reproductive phases estimated by the repeated endoscopic method.

The aim of the present study was to assess follicular and oocyte development in the same gilts during three phases of their reproductive life [prepuberal gilts (PP; 6.0 months of age), puberal gilts (P; 9.5 months of age) and primiparous sows (S)].