课程文献中心 更多>>

关键词： l-pipecolic acid   l-lysine cyclodeaminase   l-lysine riboswitch   tetA dual genetic selection   Tn5 transposon   fed-batch cultivation   L-LYSINE   EXBB-EXBD   ONE-POT   BIOSYNTHESIS   CYCLODEAMINASE   EXPRESSION   INSIGHTS  

摘要： L-Pipecolic acid is an important rigid cyclic nonprotein amino acid, which is obtained through the conversion of L-lysine catalyzed by L-lysine cyclodeaminase (LCD). To directly produce L-pipecolic acid from glucose by microbial fermentation, in this study, a recombinant Escherichia coli strain with high efficiency of L-pipecolic acid production was constructed. This study involves the dynamic regulation of the substrate concentration and the expression level of the L-lysine cyclodeaminasecoding gene pipA. In terms of substrate concentration, we adopted the L-lysine riboswitch to dynamically regulate the expression of lysP and lysO genes. As a result, the L-pipecolic acid yield was increased about 1.8-fold as compared with the control. In addition, we used chemically inducible chromosomal evolution (CIChE) to realize the presence of multiple copies of the pipA gene on the genome. The resultant E. coli strain XQ-11-4 produced 61 +/- 3.4 g/ L L-pipecolic acid with a productivity of 1.02 +/- 0.06 g/(L center dot h) and a glucose conversion efficiency (alpha) of 29.6% in fermentation. This is the first report that discovered multiple copies of pipA gene expression on the genome that improves the efficiency of L-pipecolic acid production in an L-lysine high-producing strain, and these results give us new insight for constructing the other valuable biochemicals derived from L-lysine.

摘要： 琵琶,最早写作枇杷,是所有怀抱类弹拨乐器的统称,也代指"弹、拨",右手一来一去两个重要的演奏指法,后专指今人所见这种梨形乐器. 琵琶有五弦、四弦之分,演奏方式有指弹、拨弹之别.唐太宗李世民时期,与少数民族的交流频繁,当时宫廷中就有不少少数民族的乐师,"五弦鼻祖"裴神符(又名裴洛儿)便是其中之一.他是西域疏勒(今新疆喀什)人,使用的是当时已经传入中原的"胡琵琶",即曲项五弦琵琶,当时又称"五弦".

关键词： 《十面埋伏》   琵琶曲   演奏技巧   情感表达  

摘要： 琵琶,自古以来就有"民乐之王"的美称.琵琶音乐是我国传统音乐文化的瑰宝,历史悠久,源远流长.琵琶音域极宽广,音色独特,演奏指法丰富多样,使得琵琶具有极强的表现力,可以表达出丰富的情感.《十面埋伏》是我国民族器乐作品中杰出的大型琵琶武曲,该乐曲以其独特的音乐风格和艺术魅力深受大众喜爱.基于此,文章从演奏技巧和情感表达两个方面对琵琶曲《十面埋伏》进行分析.

关键词： 琵琶   演奏艺术   传承   创新  

摘要： 中国的劳动人民以其智慧创作了丰富的民族音乐文化,建立了具有丰富内涵与广大外延的民族音乐体系,而琵琶则作为我国独有民族乐器,为世界音乐大家庭增添了光彩。琵琶演奏艺术作为一种将文化和音乐融合在一起的艺术表现形式,需要对其进行传承创新发展。