Cover Story:
Ovum pick-up (OPU) is widely used technique in livestock production. In general, OPU is performed to collect oocytes, which are then transported to the laboratory. During transportation, the oocytes are cultured in air atmosphere. Hara et al. examined the effects of oocyte transportation (conventional and modified methods) on embryonic quality (Hara S, et al. The effect of oocyte transportation on embryonic quality. p. 301–309). The conventional method induced mitochondrial dysfunction in oocytes and high DNA methylation in early embryos. However, the modified method, which uses a polysaccharide gel substrate, improved these effects. These results indicate that the modified method is a useful approach for oocyte transportation.
Cover Story:
The golden (Syrian) hamster (Mesocricetus auratus) is a small rodent belonging to the family Cricetidae, which is taxonomically distinct from laboratory Muridae rodents, such as mice and rats. Hirose et al. recently applied intraoviductal genome-editing technology (i-GONAD) to hamsters and successfully generated gene knockout (KO) strains (Hirose et al. Proc Natl Acad Sc. USA, 2020). These KO hamsters serve as unique research models, providing insights that are not attainable using mice or rats. Hirose et al. reported a simplified vitrification protocol for preserving hamster embryos, enabling safe cryopreservation of KO strains (Hirose et al., A simplified protocol for vitrification of hamster embryos, p. 290-294). To overcome the strong in vitro developmental block in hamster embryos, we used in vivo-derived 8-cell embryos. Using this approach, 21–26% of vitrified embryos developed to term after embryo transfer. Owing to its reproducibility, our vitrification protocol is broadly applicable to laboratories working with hamsters. The upper image shows a wild-type golden hamster, and the lower images show vitrified-warmed 8-cell embryos restoring their normal morphology.
Cover Story:
Plasmalogens are special types of glycerophospholipids found in the brain and blood that may help control hormone secretion. In this study, Kadokawa et al. explored whether certain laboratory-made choline plasmalogens (CPls) influence the release of reproductive hormones from cow pituitary cells (Effects of chemosynthetic choline plasmalogens on gonadotropin secretion from bovine gonadotrophs. pp. 201–209). As shown in the cover image, the researchers used computer simulations to predict how CPl molecules might attach to a specific protein on hormone-producing cells, called GPR61. One type of CPl could boost the release of a hormone called FSH, but only when another hormone (GnRH) was present. The other type of CPl had a weaker effect on its own. These results suggest that natural glycerophospholipids in the blood work together with brain signals to regulate fertility.
