‘三棱榄'橄榄果实香气成分分析

1 材料与方法选取广东优良鲜食橄榄品种‘三棱榄’,2001年12月6日采样,采用固相微萃取法(SPME)富集香气成分(鲜橄榄果肉于15℃下捣碎后取样1.0 g放入4 mL聚四氟乙烯硅橡胶垫密封螺口玻璃瓶中,插入100μm聚二甲基硅氧烷纤维头于室温25-30℃顶空取样2 h),用美国Finnigan TRACE GC-MS气相色谱-质谱联用仪进行分析。气相色谱柱为DB-1弹性毛细管柱30 m×0.25 mm,载气为He(99.99％),流速1.0mL/min。程序升温从40℃开始先保持10 min,后以2℃/min的升温速率升至150℃保持10 min。质谱条件:电子能量70 eV,离子源温度250℃,质量范围35-450 aum,不分流进样。2002年12月18日采样重复分析。

Studies on the Volatile Aroma Compounds in Fruit of Chinese White Olive Sanling (Canarium album Raeusch.)

AIM:To construct engineered E.coli strains which can express nattokinase with fibrinolysis activity using gene engineering technology.METHODS:The pro-nattokinase (pro-NK) gene was amplified by PCR and inserted into expression vector pET3c. The recombined plasmid pENK which expressed the fusion protein of pro-NK and 22 amino acid peptide was then transferred into lysogenic host strains BL21(DE3)pLysS^- and BL21(DE3)pLysS⁺. Both SDS-PAGE and the fibrin plate assay were used to examine the expression and the activity of the target protein.RESULTS:SDS-PAGE assay showed the fused gene encoding 42 kD fusion protein was expressed in both expression strains pENK-(DE3)pLysS^- and pENK-(DE3)pLysS⁺, and the fibrin plate assay indicated that the expression product had fibrinolysis activity. pENK-(DE3)pLysS^- exhibited the basal expression of the target gene, while fusion protein was only induced by IPTG in pENK-(DE3)pLysS⁺. Basal expression of the fused toxic gene in pENK-(DE3)pLysS^- led to bacteriolysis and hollow lawns.CONCLUSION:A pro-NK fusion protein with fibrinolysis activity is successfully expressed in E.coli, which lay a foundation for the exploitation of nattokinase.