Free blastocyst and implantation stages in the European brown hare: correlation between ultrasound and histological data.

The European brown hare (Lepus europaeus) is the only species with superconception, whereby the maternal reproductive tract hosts two sets of conceptuses at different developmental stages. The embryonic development of the hare has not yet been described. To understand the mechanism of superconception, we studied oviduct transport and implantation stages by embryo flushing and live high-resolution ultrasound.

Prolonged storage of epididymal spermatozoa does not affect their capacity to fertilise in vitro-matured domestic cat (Felis catus) oocytes when using ICSI.

The impact of different storage conditions of epididymal spermatozoa (including prolonged storage, cryopreservation and freeze-drying) on their fertilisation capacity was tested using intracytoplasmic sperm injection (ICSI). This kind of information is urgently needed when applying assisted reproductive technology to endangered felids in zoos. In particular, the utilisation of epididymal spermatozoa of castrated or deceased felids often requires time-consuming transportation and is therefore susceptible to loss of gamete quality.

Embryonic gene activation in in vitro produced embryos of the domestic cat (Felis catus).

Accurate embryonic gene activation (EGA) is essential for the embryo's developmental potency and reflects the quality of in vitro produced embryos. To describe the dynamic and temporal patterns of EGA in the cat, the mRNA expression of developmentally important genes (DNA methyltransferases 1 and 3A, DNMT1 and DNMT3A; gap junction protein α 1, GJA1; transcription factor octamer 4, POU5F1 (OCT4); insulin-like growth factor (IGF) 1 and 2 receptors, IGF1R and IGF2R) was examined by RT-PCR techniques in preimplantation embryos obtained after in vitro maturation and IVF. Furthermore, influences of ICSI and sperm cryopreservation on the relative mRNA abundance in 4-5-days-old morulae were analyzed.

Functional role of feline zona pellucida protein 4 trefoil domain: a sperm receptor or structural component of the domestic cat zona pellucida?

The trefoil domain (TFD) is a protein structure characterized by six cysteines, which form a typical three-loop structure by three disulphide bridges. It is assumed that two of these loops generate a hydrophobic groove, which could be a binding site for carbohydrate residues or proteins. The zona pellucida (ZP) protein, ZP4, contains such a TFD.