Molecular evolution of the exon 2 of CHS genes and the possibility of its application to plant phylogenetic analysis

The exon 2 of chalcone synthase (CHS) gene is relatively conserved during evolution. In this study, three exon 2 fragments from two species in gymnosperm (Cycas panzhihuaensis, Ginkgo biloba) and seven from four species in angiosperm (Magnolia denudata, Salix babylonica, Nymphaea tetragona, Camellia japonica) have been amplified by PCR from genomic DNA and sequenced. Together with other 73 sequences ofCHS collected from EMBL database and literature, these sequences, which embrace 19 families of gymnosperm and angiosperm, have been analyzed for their phylogenetic relations by parsimony method. The result indicated that sequences from the same systematic family usually grouped together except those from Theaceae, Magnoliaceae and Nymphaeaceae. The relative rate test revealed the rate heterogeneity of CHS genes among the families. For the nucleotide substitution the sequences from Asteraceae and Solanaceae evolve faster than those from the other families analyzed while the sequences from Poaceae, Asteraceae and Solanaceae evolve faster for the nonsynonymous substitution. These results suggest that the duplication and extinction events of CHS genes are different among systematic families, therefore it seems impractical to look for orthologous sequences from CHS genes to study plant phylogeny at the family level andlor above. However, it is possible to do so below the family level.     

糖多孢红霉菌酮还原酶域在羰基还原中的应用

为研究糖多孢红霉菌聚酮合成酶模块1的酮还原酶域,催化羰基还原的底物特异性和立体选择性,PCR扩增了该酶域的编码基因(eryKR1),并将其克隆到表达载体pET-28a,得到重组质粒pET-eryKR1,转化到Escherichia coli BL21(DE3)后,获得了重组菌株E.coli BL21(pET-eryKR1).将E.coli BL21(pET-eryKR1)和异源表达枯草芽孢杆菌葡萄糖脱氢酶基因的重组大肠杆菌E.coli BL21(pET-gdh1)进行双重组菌耦合,对4-氯乙酰乙酸乙酯、苯乙酮、2-辛酮和环己酮4种底物进行转化还原,利用气相色谱分析转化液,结果显示E.coli BL21(pET-eryKR1)对环己酮的还原效果较好,产物环己醇的得率最高可达93.24%,而对其他3种底物几乎没有还原能力.利用E.coli BL21(pET-eryKR1)2催化2-甲基环己酮不对称还原,产物主要为顺式-2-甲基环己醇,产率可达41.87%,产物的对映体过量值为74.81%.     

Oxidative photochemical decarboxylation of zaragozic acid A

A unique decomposition reaction of the novel squalene synthase inhibitors called zaragozic acids has been studied. Under very mild conditions, e.g. by merely exposing their solutions to air and visible light at ambient temperature, these compounds, characterized by the 2,8-dioxabicyclo[3.2.1]octane-4,6,7-trihydroxy-3,4,5-tricarboxylic acid core, rapidly decompose. As relatively stable intermediates in the cascade of decomposition, the biologically active 2,8-dioxabicyclo[3.2.1]octane-6,7-dihydroxy-4-keto-5-caroxylic acid (or 3,4-decarboxy-4-dehydro) derivatives of these compounds have been isolated in ca. 20% yield. Derivatization on the highly reactive 4-carbonyl group yields stable derivatives, several of which are potent inhibitors of squalene synthase. Further decomposition results in the elimination of C3 and C4 atoms and the carboxylic acid on C5, the oxidation of C5 to carboxylic acid and the liberation of the oxo group on C1. Specific results obtained with zaragozic acid A, a key representative of the family of these potent cholesterol-lowering agents, are presented in this study.     

运动训练对女子篮球运动员血清 NO、NOS活性影响的研究

通过观察6周运动训练中女大学生运动员血清NO水平、NOS活性的变化,了解篮球训练对女子运动员血清NO含量和NOS活性的影响,结果表明:实验组血清NO含量、NOS活性明显高于对照组,运动训练能够提高运动员血清NOS活性,增加NO的合成,有利于提高运动技能和保护心血管内皮的功能。     

菘蓝色氨酸合成酶基因的克隆与生物信息学分析

对菘蓝色氨酸合成酶基因IiTSA进行克隆,并对其进行生物信息学分析.结果表明:菘蓝IiTSA基因全长2 111bp,包含8个外显子和7个内含子;cDNA全长1 035bp,编码311个氨基酸,编码的蛋白定位在叶绿体基质中,是一种无信号肽和跨膜结构域的疏水性蛋白;二级结构主要由α-螺旋、β-转角、延伸链和不规则卷曲组成;序列比对结果显示,菘蓝IiTSA核酸序列和氨基酸序列与其他多种植物的TSA核酸序列和氨基酸序列均具有较高的同源性.     

葛根素对海洛因依赖大鼠心脏功能的影响及机制

目的:观察葛根素对海洛因依赖大鼠戒断期间心脏功能的变化;并探讨其与一氧化氮(NO)/一氧化氮合酶(NOS)的关系。方法:采用剂量递增法建立海洛因成瘾动物模型,共15 d,最后一次注射海洛因后腹腔注射纳洛酮并观察戒断症状。第17天,利用PowLab计算机生物信号记录分析系统测定大鼠心率(HR)、平均动脉压(mAP);并且通过测定左心室收缩压(LVSP)、左心室舒张末压(LVEDP)、左心室内压最大上升或下降速率(±dp/dtmax);采用比色法测定大鼠心肌组织匀浆中iNOS(诱导型一氧化氮合酶)活力及NO含量。结果:葛根素预处理组与heroin组比较,大鼠HR加快,mAP降低;LVSP升高、LVEDP降低、±dp/dtmax均有所升高;心肌组织iNOS的活力降低,NO的含量减少。结论:葛根素能改善海洛因对心脏功能的抑制作用,其作用与一氧化氮(NO)/一氧化氮合酶(NOS)体系有关。     

银杏GbGGPS基因的克隆及序列分析

利用RACE技术克隆并获得了银杏牻牛儿基牻牛儿基焦磷酸合成酶基因(GbGGPS基因).银杏GbGGPS基因的cDNA全长为1 641 bp,含有1个1 176 bp的可读框,编码391个氨基酸序列.生物信息学预测GbGGPS蛋白的分子质量为42.51 ku,理论等电点为5.98,N端有叶绿体信号肽,其二级结构主要由α-螺旋和无规则卷曲组成.蛋白质同源分析表明,GbGGPS含有多聚异戊二烯基合成酶家族中保守的5个特征性结构域和2个富含天冬氨酸的区域.同源建模分析显示GbGGPS序列与薄荷GGPS蛋白的三维结构及活性位点高度相似.系统进化分析表明,银杏GGPS蛋白归属植物进化支,且与加拿大红豆杉、挪威云杉、北美冷杉的GGPS蛋白归为同一分支.     

加热炉自动燃烧控制模型功能浅析

介绍了太钢2250热连轧厂加热炉自动燃烧控制模型(ACC)系统,分析了加热炉自动燃烧控制模型的组成和实现方法.     

黄蜀葵查尔酮合成酶基因AmCHS克隆及序列分析

从黄蜀葵(Abelmoschus manihot) 花瓣中通过简并引物克隆得到查尔酮合成酶基因cDNA 核心序列,根据核心序列设计特异引物,再应用5′RACE 和3′RACE 技术分别扩增该序列的5′末端和3′末端序列,最后通过序列拼接获得黄蜀葵查尔酮合成酶基因（AmCHS）cDNA全序列.序列分析结果表明AmCHS cDNA编码区长1170 bp,编码389个氨基酸。其氨基酸序列与其它已知高等植物CHS基因具有很高的同源性,并且包含了CHS 具有的活性位点和催化位点等保守性位点.