Comparing α-carbanion-stabilizing ability of substituents using the Brook rearrangement

The α-carbanion-stabilizing ability of the phenylthio and trimethylsilyl groups was compared based on the relative rate of the base-catalyzed Brook rearrangement of the β-substituted α-silylallylalcohol

Mother-to-embryo vitellogenin transport in a viviparous teleost Xenotoca eiseni

魚類がお腹の子供に与える栄養素を解明 --哺乳類が失った遺伝子を利用して胎生機構を獲得--. 京都大学プレスリリース. 2019-10-09.Vitellogenin (Vtg), a yolk nutrient protein that is synthesized in the livers of female animals, and subsequently carried into the ovary, contributes to vitellogenesis in oviparous animals. Thus, Vtg levels are elevated during oogenesis. In contrast, Vtg proteins have been genetically lost in viviparous mammals, thus the yolk protein is not involved in their oogenesis and embryonic development. In this study, we identified Vtg protein in the livers of females during the gestation of the viviparous teleost, Xenotoca eiseni. Although vitellogenesis is arrested during gestation, biochemical assays revealed that Vtg protein was present in ovarian tissues and lumen fluid. The Vtg protein was also detected in the trophotaeniae of the intraovarian embryo. Immunoelectron microscopy revealed that Vtg protein is absorbed into intracellular vesicles in the epithelial cells of the trophotaeniae. Furthermore, extraneous Vtg protein injected into the abdominal cavity of a pregnant female was subsequently detected in the trophotaeniae of the intraovarian embryo. Our data suggest that the yolk protein is one of the matrotrophic factors supplied from the mother to the intraovarian embryo during gestation in X. eiseni