Extracellular Vesicles Contribute to the Difference in Lipid Composition between Ovarian Follicles of Different Size Revealed by Mass Spectrometry Imaging.

Follicular fluid (FF) ensures a safe environment for oocyte growth and maturation inside the ovarian follicle in mammals. In each cycle, the large dominant follicle (LF) contains the oocyte designated to be ovulated, whereas the small subordinate follicles (SFs) of the same wave will die through atresia. In cows, the oocytes from the SF, being 2 mm in size, are suitable for in vitro reproduction biotechnologies, and their competence in developing an embryo depends on the size of the follicles.

Cytokine supplemented maturation medium improved development to term following somatic cell nuclear transfer (SCNT) in cattle.

Context: In vitro maturation is an important process in the production of embryos. It has been shown that three cytokines, fibroblast growth factor 2, leukemia inhibitory factor and insulin-like growth factor 1 (FLI), increased efficiency of in vitro maturation, somatic cell nuclear transfer (SCNT) blastocyst production, and in vivo development of genetically engineered piglets.

Aims: Assess effects of FLI on oocyte maturation, quality of oocytes, and embryo development in bovine in vitro fertilisation (IVF) and SCNT.

Centrosome Formation in the Bovine Early Embryo.

Centrosome formation during early development in mice and rats occurs due to the appearance of centrioles de novo. In contrast, in humans and other non-rodent mammals, centrioles are thought to be derived from spermatozoa. Ultrastructural study of zygotes and early embryos of cattle at full series of ultrathin sections show that the proximal centriole of the spermatozoon disappears by the end of the first cleavage division.