Strain LT/Sv female mice show a high frequency of spontaneous ovarian teratomas arising from parthenogenetically activated follicular oocytes. LT/Sv oocytes also arrest at metaphase of meiosis I, rather than progressing through to metaphase II, as do almost all fully grown oocytes from most other strains. We investigated a new set of recombinant inbred strains derived from BALB/c and C58 (the p...

IN THE PRESENT WORK, SIX CURIMATID SPECIES WERE ANALYZED Cyphocharax voga (Hensel, 1870), Cyphocharax spilotus (Vari, 1987), Cyphocharax saladensis (Meinken, 1933), Cyphocharax modestus (Fernández-Yépez, 1948), Steindachnerina biornata (Braga & Azpelicueta, 1987) and Steindachnerina insculpta (Fernández-Yépez, 1948) collected from two hydrographic basins. All samples presented 2n=54 meta-submet...

The quality of mammalian oocytes declines with age, which negatively affects fertilization and developmental potential. The aging process often accompanies damages to macromolecules such as proteins, DNA, and lipids. To investigate if aged oocytes display an altered lipidome compared to young oocytes, we performed a global lipidomic analysis between oocytes from 4-week-old and 42 to 50-week-old...

Holocentric chromosomes occur in a number of independent eukaryotic lineages. They form holokinetic kinetochores along the entire poleward chromatid surfaces, and owing to this alternative chromosome structure, species with holocentric chromosomes cannot use the two-step loss of cohesion during meiosis typical for monocentric chromosomes. Here we show that the plant Luzula elegans maintains a h...

From 1 August 1993 until 30 September 1994, 69 couples suffering from azoospermia underwent testicular sperm extraction and intracytoplasmic sperm injection. In 50 couples with obstructive azoospermia a total of 631 metaphase-II oocytes were injected after testicular sperm extraction yielding a 2-PN fertilization rate of 57%. In female patients <40 years of age an ongoing pregnancy rate per tra...

This study examines the timing of changes in chromosome configurations of pig oocytes derived from small antral follicles of follicular and/or inactive stage donors using modified 199 medium supplemented with gonadotropins (Follicle Stimulating Hormone (FSH), 10 IU/ml; Human Chorionic Gonadotropin (hCG), 10 IU/ml) and Glucosamine (0.539 mg/ml). Oocytes (n = 1,215) were fixed at the end of 3 hou...

The dynamics of the Aurora B protein kinase during Xenopus oocyte meiotic maturation were examined. Resting G2 oocytes express inactive Aurora B that is not associated with other subunits of the chromosome passenger complex (CPC). Activity increases near the time of germinal vesicle breakdown in progesterone-treated oocytes, and this increase is correlated with the synthesis of inner centromere...

introduction: the purpose of this study was to investigate the effect of vitrification procedure on the survival, fertilization, development and ultrastructure of metaphase (mii) mouse oocyte. materials and methods: female nmri mice 6-10 weeks old were superovulated using ip injection of 10 iu hmg and 10 iu hcg. ovulated oocyte were collected from the ampullary portion of the oviducts at 12-13 ...