The somatic cell nuclear transfer （SCNT） technique has been applied successfully in a range of mammalian species giving rise to offspring, however, the efficiency of development to term has remained low. Oocyte meio...The somatic cell nuclear transfer （SCNT） technique has been applied successfully in a range of mammalian species giving rise to offspring, however, the efficiency of development to term has remained low. Oocyte meiotic arrest is an important option to make the SCNT more flexible and increase the number of cloned embryos produced. This paper showed that the use of butyrolactone I to arrest the meiotic division for 24 h prior to in vitro maturation （IVM） provided bovine oocytes capability of supporting development of blastocysts as efficiently as non arrested oocytes. In the SCNT group, cleavage rates were not affected by prematuration when adding butyrolactone I during IVM （57.9% vs. 62.4%; control vs. 10 μmol.L^-1 butyrolactone I）, developmental rates to biastocyst were unaffected （22.0% vs. 20.3%; control vs. 10 μmol.L^-1 butyrolactone I, p〉0.05） by the addition ofbutyrolactone I during IVM in cloned embryos. Moreover, the total cell numbers of blastocyst were not affected by butyrolactone I （total nucleus numbers, 132±16.5 vs. 128±19.4, p〉0.05）. In conclusion, the SCNT embryos from butyrolactone I- prematured bovine oocytes had the same developmental potential as the non treated one. The present study provided a method for laboratories of in vitro embryos production, mainly those working on the SCNT, where prematuration could be used to iiacrease the flexibility of the procedure.展开更多
Cyclopropylamine is synthesized with γ butyrolactone and isopropanol by five steps of ring opening esterification, cyclization, hydrolysis, acylation and Hofmann degradation. Cyclization and hydrolysis are key steps ...Cyclopropylamine is synthesized with γ butyrolactone and isopropanol by five steps of ring opening esterification, cyclization, hydrolysis, acylation and Hofmann degradation. Cyclization and hydrolysis are key steps in the process, and Phase Transfer Catalysis (PTC) is used in the two steps respectively. In the cyclization reaction, because solid liquid PTC, sodium hydroxide is applied instead of expensive sodium alcoholate, the reaction can be carried out in mild conditions. The optimum re action conditions are as follows: 0.03∶1∶1.5 mole ratio of BTEAC to ester to sodium hydroxide, reacting at 50 ℃ for 2 h with yield of 92%. Hydrolysis of isopropyl cyclopropanecarboxylate is accelerated by liquid liquid PTC, and the order of catalytic activity is BTEAC>BTMAC>CTMAB>TBAB. The results show that the new synthesis method is superior to those from literature and feasible for production with simple routes, mild reaction conditions, cheap materials and total yield of 52.6%.展开更多
基金Supported by the Scientific Research Fund of Heilongjiang Provincial Education Department (11531028)Heilongjiang Postdoctoral Fund (LBH-Z11245)
文摘The somatic cell nuclear transfer （SCNT） technique has been applied successfully in a range of mammalian species giving rise to offspring, however, the efficiency of development to term has remained low. Oocyte meiotic arrest is an important option to make the SCNT more flexible and increase the number of cloned embryos produced. This paper showed that the use of butyrolactone I to arrest the meiotic division for 24 h prior to in vitro maturation （IVM） provided bovine oocytes capability of supporting development of blastocysts as efficiently as non arrested oocytes. In the SCNT group, cleavage rates were not affected by prematuration when adding butyrolactone I during IVM （57.9% vs. 62.4%; control vs. 10 μmol.L^-1 butyrolactone I）, developmental rates to biastocyst were unaffected （22.0% vs. 20.3%; control vs. 10 μmol.L^-1 butyrolactone I, p〉0.05） by the addition ofbutyrolactone I during IVM in cloned embryos. Moreover, the total cell numbers of blastocyst were not affected by butyrolactone I （total nucleus numbers, 132±16.5 vs. 128±19.4, p〉0.05）. In conclusion, the SCNT embryos from butyrolactone I- prematured bovine oocytes had the same developmental potential as the non treated one. The present study provided a method for laboratories of in vitro embryos production, mainly those working on the SCNT, where prematuration could be used to iiacrease the flexibility of the procedure.
基金The Science and Research Foundation of Education Commission of Hunan Province
文摘Cyclopropylamine is synthesized with γ butyrolactone and isopropanol by five steps of ring opening esterification, cyclization, hydrolysis, acylation and Hofmann degradation. Cyclization and hydrolysis are key steps in the process, and Phase Transfer Catalysis (PTC) is used in the two steps respectively. In the cyclization reaction, because solid liquid PTC, sodium hydroxide is applied instead of expensive sodium alcoholate, the reaction can be carried out in mild conditions. The optimum re action conditions are as follows: 0.03∶1∶1.5 mole ratio of BTEAC to ester to sodium hydroxide, reacting at 50 ℃ for 2 h with yield of 92%. Hydrolysis of isopropyl cyclopropanecarboxylate is accelerated by liquid liquid PTC, and the order of catalytic activity is BTEAC>BTMAC>CTMAB>TBAB. The results show that the new synthesis method is superior to those from literature and feasible for production with simple routes, mild reaction conditions, cheap materials and total yield of 52.6%.
