酯酶基因Est2的异源表达及酶学性质研究

对来自α/β水解酶超家族的酯酶基因Est2进行了克隆、异源表达及纯化,然后对其酶学性质进行了研究.研究结果显示:酯酶Est2的最适底物为对硝基苯乙酸酯(p-NPC2),最适反应温度为50℃,最适pH为8.0;Est2具有较好的pH稳定性,在pH 5.0～10.0范围内,其相对酶活性保持在50％以上;在40℃条件下具有最...     

利用微卫星标记定位水稻红莲型细胞质雄性不育恢复基因

以 (丛广 41A×密阳 2 3)×丛广 41B回交群体为基因定位群体 ,采用群分法 ,对红莲型细胞质雄性不育恢复基因进行了定位 .在 1 5 9对微卫星引物中 ,微卫星标记RM2 5 8与红莲型细胞质雄性不育恢复基因连锁 ,从而将该基因定位于水稻第 1 0染色体上 ,距RM2 5 8约 7.8cM ,恢复基因在染色体上可能是成簇分布的     

油菜Polima和陕2A细胞质雄性不育系相关基因的序列比较

orf224是在油菜Polima胞质中发现的一个与细胞雄性不育相关的线粒体基因,陕2A不育系则是我国第一个大面积推广的杂交油菜品种“秦油2号”的亲三,Polima和陕2A的基因组DNA为模板,通过合成5′和3′端一对待异引物,利用多聚酶链式反应(polymerase chain reaction,PCR）从两个不育系的基因组DNA中都扩增出了与orf224同源的DNA片段,将其克隆到pGEM-TEasy载体上进行序列测定,测序结果表明：两序列均由675个核苷酸组成,编码224个氨基酸组成的多肽,两序列的核苷酸及推导出的氨基酸同源性分别为99．9％和99．6％,在＋398处两者有一个碱基的差异（AAC→AGC）和一个氨基酸的差异（Asn→Ser）,从而证实了Polima和陕2A为线粒体上同一座位的不同等位基因的差异。     

Elucidation of the molecular mechanism of widely-used WA type cytoplasmid male sterility in hybrid rice

Hybrid rice is a great achievement of China in agriculture.Three-line hybrid rice breeding is mainly based on the exploitation of cytoplasmic male sterility（CMS）systems.The molecular mechanisms on CMS induction in plants are largely unknown.With the support from the National Natural Science Foundation of China,the research group headed by Prof.Liu Yaoguang in South China Agricultural University has conducted a series of innovative studies focusing on the gene isolation and mechanistic analyses of CMS systems in rice.     

Rational design of glycerol dehydratase： Swapping the genes encoding the subunits of glycerol dehydratase to improve enzymatic properties

1,3-propanediol (1,3-PD) is an important material for chemical industry,and there has been always much interest in the production of 1,3-PD using all possible routes. The genes encoding glyc-erol dehydratase (GDHt) from Citrobacter freundii,Klebsiella pneumoniae and metagenome were cloned and expressed in E. coli. All glycerol dehy-dratases but the one from metagenome could be detected to show enzyme activities. In order to im-prove the enzymatic properties of GDHts,the genes encoding α and β-γ subunits were cloned,and the enzyme characteristics were evolved by rational de-sign based on their 3D structures which were con-structed by homology modeling. Six heteroenzymes were obtained by swapping the α subunit genes of these three different-source-derived GDHts. The pH,thermal stability and Vmax of some heteroenzymes were dramatically improved by 2―5 times compared with the wild one (GDHtKP). The GDHt cloned from metagenome,originally proved to be with no enzyme activity,was converted into active enzyme by swap-ping its subunits with other different GDHts. In addi-tion,the effect of subtle 3D structural changes on the properties of the enzyme was also observed.     

猕猴桃种间体细胞杂种细胞质DNA遗传的初步分析

提取猕猴桃体细胞杂种叶片总DNA,PCR和限制性内切酶,分析了叶绿体基因组的trnT(UGU)和5'trnL(UAA)外显子之间的a～b间隔区DNA片段和光合系统Ⅱ D1蛋白基因(psbA)片段,以及线粒体基因组的ORF25片段的遗传特征.结果表明,狗枣猕猴桃(A.kolomikta)与中华猕猴桃(Actinidia chinensis)的对称体细胞杂种具有与中华猕猴桃相同的a～b间隔区DNA片段,叶绿体DNA遗传为非随机分离.还讨论了cpDNA遗传与猕猴桃种间的亲缘关系.     

植物细胞质雄性不育的分子机理研究进展

对细胞质雄性不育(CMS)的研究不仅在杂种优势利用上具有重要的实践意义,而且在研究核质互作方面具有重要理论意义,文中主要从CMS的胞质基因载体和核基因组对CMS的影响两个方面综述了近年来植物CMS分子机理的研究进展,并对今后的研究方向进行了讨论.     

中国水稻农家品种马尾粘败育株细胞质雄性不育系（马…

１９８４年在中国水稻农家品种马尾粘中发现花粉败育型雄性不育株，用协青早选杂和连续回效选育成马协型雄性不育系，对马协不育系的特征特性，开花习性，花粉败育的细胞学特征，细胞质质量，线粒体ＤＮＡ和线粒体ＣＯＤ同工酶等进行比较研究，结果表明，马协雄性不育系是一种新的细胞质雄性不育系，具有重要的理论意义和实践价值，利用马协不育系与明恢６３配组马协６３杂交稻组合具有优质，高产，多抗特点，通过了湖北省和僵杂交稻     

Effects of truncated mutants of the ε subunit of chloroplast ATP synthase on the fast phase of millisecond delayed light emission of chloroplast and its ATP synthesis ability

The ε subunit of the chloroplast ATP synthase and the truncated ε mutants which lack some amino acid residues from the N-terminus or C-terminus were overexpressed in E. coil When the ε subunit or the truncated ε proteins was added to the spinach chloroplast suspension, both the intensity of the fast phase of millisecond delayed light emission (ms-DLE) and the cyclic and noncyclic photophosphorylation activity of chloroplast were enhanced. With an increase in the number of residues deleted from the N-terminus, the enhancement effect of the N-terminal truncated proteins decreased gradually. For the C-terminal truncated proteins, the enhancement effect increased gradually with an increase in the number of residues deleted from the C-terminus. Besides, the ATP synthesis activity of ε-deficient membrane reconstituted with the ε subunit or the truncated ε proteins was compared. The ATP synthesis activity of reconstituted membrane with the N-terminal truncated proteins decreased gradually as the number of residues deleted from the N-terminus increased. For the C-terminal truncated proteins, the ATP synthesis activity of reconstituted membrane increased gradually with an increase in the number of residues deleted from the C-terminus, but was still lower than that of the wild type ε protein. These results suggested that: (a) the N-terminal domain of the ε subunit of the chloroplast ATP synthase could affect the ATP synthesis activity of ATP synthase by regulating the efficiency of blocking proton leakage of ε subunit; and (b) the C-terminal domain of the ε subunit of the chloroplast ATP synthase had a subtle function in modulating the ATP synthesis ability of ATP synthase.