从线粒体和叶绿体基因组的结构看生物基因组的进化

通过分析各类真核生物线粒体和叶绿体基因组的大小与结构,得出这两种细胞器基因组都有小基因组与大基因组两种形式以及与之对应的结构特点,从而都是通过两种进化途径从它们各自祖先的基因组发展成为现代的线粒体和叶绿体基因组的结论。比较细胞器基因组与核（类核）基因组的存在和性质,发现类似的两种途径同样可以说明核（类核）基因组的进化。结合这三种基因组的起源问题,提出了一个生物基因组起源和进化的统一模式。     

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.     

Present status and development on biological nitrogen fixation research in China

This presentation introduces the advances in biological nitrogen fixation research abroad, in particular,describes the great progress and achievements on its research in China as follows: collection of rhizobial resources and establishment of the largest database of Rhizobium in China, correction and development of Rhizobium taxonomy in international; discovery of a couple of nif genes, identification and unification of linkage among the nif gene operons of Klebsiella pneumoniae, finding of regulative mechanism of positive regulation nif gene and its sensitivity to oxygen,temperature; finding of the activity of nodulation gene nodD3 product in Sinorhizobium meliloti which is not controlled by flavonoid produced from its host alfalfa; finding of the association between expression of genes coding the products for carbon utilization and nitrogen metabolism and their regulations; chemical synthesis of nodulation factor of Sinorhizobium meliloti; constructions of engineered nitrogen fixers and utilization in practice based on the research of gene expression and regulation; chemical simulation of the structure and function of nitrogenase and bringing forward the model of nitrogenase active center for the first time in international and synthesis of model compounds which were paid attention by colleagues abroad. Finally, the development of nitrogen fixation research in China in future has been put forward, suggesting that the nif gene regulation and its role in providing crops with nitrogen element, signal transduction and molecular interactions between Rhizobium and legume, coupling between carbon and nitrogen metabolisms, nitrogen fixation and photosynthesis, and functional genomics of nitrogen-fixing nodule symbiosis, etc., would be actively worked on.     

Mitochondrial genetic variation within and between Holbrookia lacerata lacerata and Holbrookia lacerata subcaudalis,the spot-tailed earless lizards of Texas

ABSTRACT

We examined genetic relationships among individuals and populations of the species Holbrookia lacerata, the spot-tailed earless lizard, using whole mitochondrial genomes. Lizards were collected from south, central and west Texas. We found significant amounts of genetic structure among populations and evidence of two major reciprocally monophyletic groups of spot-tailed earless lizards in Texas. Holbrookia lacerata lacerata occurs on the Edwards Plateau and adjacent regions of West Texas north of the Balcones Escarpment, while Holbrookia lacerata subcaudalis occurs in South Texas and adjacent Mexico south of the Balcones Escarpment. These two recognised subspecies correspond to the two clades we discovered. Holbrookia l. lacerata occupies much of its historical range at sometimes high population densities, while populations of H. l. subcaudalis appear to be highly fragmented based on recent observations compared to their historical range.     

细菌和酵母基因组中ORF结构特征的统计分析

将第一ATG规则用于细菌Hpyl，Hpyl99，E.coli，Aero，Tmar和Yeast基因组中，并用给出ORF(包含已知基因编码区)进行检验，其结果对以ATG起始的ORF序列正确率皆为89％以上，将五种细菌和酵母基因组中给出ORF分成第一种(已确定的编码序列)和第二种(还未确定为编码序列的)ORF，并计算L—Ter到第一ATG的平均距离，分析了五种细菌和酵母终止密码子在L-Ter位置和Ter位置上的使用频率，发现在Ter位置上终止密码子使用的偏置程度比在L-Ter位置上大．     

基于线粒体蛋白编码基因探讨飞虱科Delphacidae13属系统发育关系

飞虱科昆虫隶属于半翅目蜡蝉总科,是世界上最重要的农业害虫之一.昆虫的线粒体基因是昆虫分子与进化研究中常用且有效的分子标记.本研究基于线粒体蛋白编码基因探讨了飞虱科13属18种的系统发育关系,分别采用距离法、最大似然法和贝叶斯法构建的系统发育树得到的结论是一致的,即在飞虱科13属中,Ugyops属较为原始,处于系统树的基...     

移位变换下一类进化树的重构问题

讨论多重基因组在移位变换下的一类进化树的重构问题：给定一个由若干基因组组成的集族∏与另一个基因组A，其中所有基因组由同样的一些有向的基因组成，且每个基因组由相同数目的染色体组成，每一个基因在每个基因组中恰好出现一次，所有基因组有相同的尾基因集合，要求构造一个由A到∏的进化树，使得沿此树所发生的移位变换数目最少．给出由一个基因组生成一些给定基因组的近似算法；在一个特殊情况下给出其多项式时间算法．     

原核生物和酵母基因组中起始密码的特征分析

提出了一个识别基因起始密码子的第一ATG规则，用酵母基因组中的已知基因检验，正确率为99．9％；用大肠杆菌基因组中已知以ATG起始的基因进行检验，正确率为92．9％；用枯草杆菌基因组中已知以ATG起始的基因的进行检验，正确率为81．0％，统计了L－Ter（上游最后一个终止密码）到起始密码子之间的距离（记为D值），酵母的平均长度是17个碱基；在大肠杆菌和枯草杆菌中，以ATG起始的基因的D值分别是36和33个碱基；以非ATG起始的基因的D值分别是39和32个碱基；解释了真核和原核生物D值差别的原因；发现大肠杆菌和枯草杆菌中，以ATG起始的基因和以非ATG起始的基因序列的构造差异。认为L－Ter到起始密码子之间的序列可能是mRNA先导充列的主要结构。     

基于网络药理学的五苓散多成分-多靶点-多通路作用机制研究

通过中药系统药理学数据库与分析平台（traditional Chinese medicine system pharmacology datebase and analysis platform,TCMSP)筛选五苓散组分白术、茯苓、猪苓、泽泻、桂枝的潜在活性成分,PharmMapper服务器预测潜在靶点,构建化合物-靶点网络、蛋白互作( protein-protein interaction,PPI) 网络,进行基因本体( gene ontology,GO) 富集分析、基于KEGG( Kyoto encyclopedia of genes and enomes) 的生物通路富集分析。结果表明,筛选得到五苓散中50种活性成分,构建化合物 靶点网络共459个节点,关键靶点包括CSDE1、PRPS1、HSD17B4、CLPP、ACBD7、AZGP1等。构建五苓散靶点的PPI互作网络包含155个节点和527条相互作用关系,关键节点包括CSDE1、CITED2、RANBP2、HSD17B4、TAF13、SOD2等。GO富集分析途径相关条目主要涉及细胞溶质、细胞对有机物质和化学刺激的反应,含氮物质代谢,有机物循环代谢进程,蛋白、小分子和离子结合及转运活性等。KEGG代谢通路分析包括膀胱癌、前列腺癌、内分泌抵抗、癌症中的蛋白聚糖、流体剪切应力和动脉粥样硬化等途径。研究结果初步验证了五苓散药理作用的分子机制,为进一步深入揭示其分子作用机制奠定了基础,预测五苓散的潜在作用靶点如PRPS1、HSD17B4等,可为五苓散的深入研究提供新思路。