In order to improve the production of human-like collagen III(HLC III)by fed-batch culture of recombinant Escherichia coli BL21,the Plackett-Burman and Box-Behnken design were applied to optimize the fermentation proc...In order to improve the production of human-like collagen III(HLC III)by fed-batch culture of recombinant Escherichia coli BL21,the Plackett-Burman and Box-Behnken design were applied to optimize the fermentation process parameters.Three variables(induction time,inoculum age and pH),which have significant effects on HLC III production,were selected from eight variables by Plackett-Burman design.With the regression coefficient analysis in the Box-Behnken design,a relationship between HLC III production and three significant factors was obtained,and the optimum levels of the three variables were as follows:induction time 3.2h,inoculum age 12.6 h and pH 6.7.The 3D response surface plots and 2D contour plots created by the Box-Behnken design showed that the interaction between induction time and pH and that between innoculum age and pH were significant.An average 9.68 g·L1HLC III production was attained in the validation experiment under optimized condition,which was 80%higher than the yield of 5.36 g·L1before optimization.展开更多
The world of Ingmar Bergman is notoriously dark. He exposes us repeatedly to the isolation of human subjectivity and to our desperate attempts to break free of it. To be human for Bergman is to be imperiled, to move i...The world of Ingmar Bergman is notoriously dark. He exposes us repeatedly to the isolation of human subjectivity and to our desperate attempts to break free of it. To be human for Bergman is to be imperiled, to move in an atmosphere of relentless anxiety, and to be driven by passions whose source and power we can neither master nor understand. Is there a period of innocence, a time before we are caught in the coils of the human condition？ The author will argue that Bergman＇s treatment of children demonstrates that in his world birth is the fall from grace.展开更多
基金Supported by the National Natural Science Foundation of China（20776119） the National High Technology Research and Development Program of China（2007AA03Z456A） the Special Research Program of the Education Department of Shaanxi Province（07JK417）
文摘In order to improve the production of human-like collagen III(HLC III)by fed-batch culture of recombinant Escherichia coli BL21,the Plackett-Burman and Box-Behnken design were applied to optimize the fermentation process parameters.Three variables(induction time,inoculum age and pH),which have significant effects on HLC III production,were selected from eight variables by Plackett-Burman design.With the regression coefficient analysis in the Box-Behnken design,a relationship between HLC III production and three significant factors was obtained,and the optimum levels of the three variables were as follows:induction time 3.2h,inoculum age 12.6 h and pH 6.7.The 3D response surface plots and 2D contour plots created by the Box-Behnken design showed that the interaction between induction time and pH and that between innoculum age and pH were significant.An average 9.68 g·L1HLC III production was attained in the validation experiment under optimized condition,which was 80%higher than the yield of 5.36 g·L1before optimization.
文摘The world of Ingmar Bergman is notoriously dark. He exposes us repeatedly to the isolation of human subjectivity and to our desperate attempts to break free of it. To be human for Bergman is to be imperiled, to move in an atmosphere of relentless anxiety, and to be driven by passions whose source and power we can neither master nor understand. Is there a period of innocence, a time before we are caught in the coils of the human condition？ The author will argue that Bergman＇s treatment of children demonstrates that in his world birth is the fall from grace.
