Abstract.To induce meiotic resumption of porcine oocytes, it is thought to be necessary to expose the cumulus-oocyte complexes (COCs) to gonadotropins during in-vitro maturation (IVM). However, the detailed mechanism of meiotic resumption by gonadotropins is still unknown, and successful piglet production has not been reported by using oocytes matured in gonadotropin-free media and fertilized in vitro. The present study was undertaken to examine the combinational effects of epidermal growth factor (EGF)-family members and dibutyryl cyclic AMP (cAMP) in a chemically defined medium on IVM of porcine oocytes and the developmental competence following in vitro fertilization (IVF). The basic IVM medium was a chemically defined medium, modified porcine oocyte medium (mPOM). Supplementation of the IVM medium with 10 or 1000 ng/ml EGF, amphiregulin and betacellulin during the whole IVM period, except for 10 ng/ml amphiregulin, increased the percentage of oocytes maturing to the metaphase-II stage. When COCs were exposed to both dibutyryl cAMP and EGF-family members during the first 20-h of IVM and then culture was continued in the absence of EGF-family members and dibutyryl cAMP, the incidence of metaphase-II oocytes was significantly increased and was not different from that of oocytes cultured in a standard IVM system with gonadotropins. The developmental competence of the oocytes to the blastocyst stage following IVF was no different from that of control oocytes matured with gonadotropins. When these blastocysts were transferred into the uterine horn of three recipients, all of gilts became pregnant and delivered a total of 11 piglets. These observations indicate that supplementation of a chemically defined maturation medium with EGF-family members and dibutyryl cAMP during the first 20 h of IVM can support well the meiotic progress and developmental competence of porcine oocytes. Key words: Cyclic AMP (cAMP), Epidermal growth factor (EGF), In vitro maturation, Oocyte, Pig (J. Reprod. Dev. 55: [446][447][448][449][450][451][452][453] 2009) uccessful in-vitro production of porcine embryos has the potential to provide an effective system for mass production of embryos for better understanding of the physiology of embryonic development and animal reproductive technologies, including production of transgenic and/or cloned animals [1,2]. Relatively efficient systems for in-vitro production of porcine embryos have already been developed, but they contain materials derived from organisms, such as porcine follicular fluid and bovine serum albumin, in the culture media [3,4]. Chemically defined media, which only known chemicals, but none derived from animals, yeast or plants, should be useful in clarifying the mechanism of interactive communication between the oocyte and the surrounding cumulus cells during meiosis, the oocyte reaction following sperm penetration and early development. Furthermore, application of a defined system for in-vitro embryo production would be good for a quality control against the risk of viral c...

An efficient synthesis of bioactive chiral flavanones (1) was achieved through the Rh-catalyzed asymmetric 1,4-addition of arylboronic acid to chromone. The reaction in toluene proceeded smoothly at room temperature in the presence of 0.5% Rh catalyst with electron-poor chiral diphosphine MeO-F(12)-BIPHEP. In this reaction, the 1,2-addition to (S)-1 frequently occurred to yield (2S,4R)-2,4-diaryl-4-chromanol as a byproduct, which could be reduced by changing the reaction solvent to CH(2)Cl(2) to deactivate the Rh catalyst (3% required).

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A variety of bioactive flavanones is prepared.

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