Transcriptomic analysis of ovarian signaling at the emergence of the embryo from obligate diapause in the American mink (Neovison vison)

Metabolomic Profiling of Female Mink Serum during Early to Mid-Pregnancy to Reveal Metabolite Changes

Mink embryos enter a period of diapause after the embryo develops into the blastocyst, and its reactivation is mainly caused by an increase in polyamine. The specific process of embryo diapause regulation and reactivation remains largely unexamined. This study aimed to identify changes in metabolites in the early pregnancy of mink by comparing and analyzing in serum metabolites up to twenty-nine days after mating. Blood samples were taken on the first day of mating, once a week until the fifth week. Metabolomic profiles of the serum samples taken during this period were analyzed by ultra-performance liquid chromatography/mass spectrometry. Multivariate statistical analyses identified differential metabolite expression at different time points in both positive and negative ion modes. The levels of dopamine, tyramine, L-phenylalanine, L-tyrosine, tyrosine, L-kynurenine, L-lysine, L-arginine, D-ornithine, and leucine changed significantly. These metabolites may be associated with the process of embryo diapause and subsequent reactivation.

Integrative Proteomic and Phosphoproteomic Analyses Revealed Complex Mechanisms Underlying Reproductive Diapause in Bombus terrestris Queens

Reproductive diapause is an overwintering strategy for Bombus terrestris, which is an important pollinator for agricultural production. However, the precise mechanisms underlying reproductive diapause in bumblebees remain largely unclear. Here, a combination analysis of proteomics and phosphoproteomics was used to reveal the mechanisms that occur during and after diapause in three different phases: diapause (D), postdiapause (PD), and founder postdiapause (FPD). In total, 4655 proteins and 10,600 phosphorylation sites of 3339 proteins were identified. Diapause termination and reactivation from D to the PD stage were characterized by the upregulation of proteins associated with ribosome assembly and biogenesis, transcription, and translation regulation in combination with the upregulation of phosphoproteins related to neural signal transmission, hormone biosynthesis and secretion, and energy-related metabolism. Moreover, the reproductive program was fully activated from PD to the FPD stage, as indicated by the upregulation of proteins related to fat digestion and absorption, the biosynthesis of unsaturated fatty acids, fatty acid elongation, protein processing in the endoplasmic reticulum, and the upregulation of energy-related metabolism at the phosphoproteome level. We also predicted a kinase-substrate interaction network and constructed protein-protein networks of proteomic and phosphoproteomic data. These results will help to elucidate the mechanisms underlying the regulation of diapause in B. terrestris for year-round mass breeding.

Glycine and Melatonin Improve Preimplantation Development of Porcine Oocytes Vitrified at the Germinal Vesicle Stage

Lipid-rich porcine oocytes are extremely sensitive to cryopreservation compared to other low-lipid oocytes. Vitrification has outperformed slowing freezing in oocyte cryopreservation and is expected to improve further by minimizing cellular osmotic and/or oxidative stresses. In this study, we compared the effects of loading porcine cumulus-oocyte complexes with glycine (an organic osmolyte) or glycine plus melatonin (an endogenous antioxidant) during vitrification, thawing and subsequent maturation to mitigate osmotic injuries or osmotic and oxidative damages on the developmental potential of porcine oocytes. Our data demonstrated that glycine treatment significantly increased the vitrification efficiency of porcine oocytes to levels comparable to those observed with glycine plus melatonin treatment. It was manifested as the thawed oocyte viability, oocyte nuclear maturation, contents of reactive oxygen species, translocation of cortical granules and apoptotic occurrence in mature oocytes, levels of ATP and transcripts of glycolytic genes in cumulus cells (markers of oocyte quality), oocyte fertilization and blastocyst development. However, the latter was more likely than the former to increase ATP contents and normal mitochondrial distribution in mature oocytes. Taken together, our results suggest that mitigating osmotic and oxidative stresses induced by vitrification and thawing can further enhance the developmental competency of vitrified porcine oocytes at the germinal vesicle stage.