5种白蚁基因组DNA随机扩增多态性研究

采用RAPD（Random amplified polymorphic DNA)技术对尖唇异白蚁（Heterotermes aculabialis)、黄肢散白蚁（Reticulitermes flaviceps)、扩头散白蚁（R.ampliceps)、细颚木鼻白蚁（Stylotermes angustignathus)和陇南树白蚁（Glyptotermes longnanensis)等5种白蚁的基因组DNA多态性进行了初步分析。在所用的20个随机引物中有4个引物能扩增出稳定的带型,5种白蚁6个群体共扩增出43条带,均为多态性片段;同一种类不同群体和同一群体不同品级间存在一定程度的多态性,但种间扩增片段差异显著大于种内差异。以UPGMA方法将扩增片段分布和共享度数据矩阵进行聚类分析,所得结果支持我国异白蚁属与散白蚁属合并的观点。     

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.     

A Chemometry of Aldrovanda vesiculosa L. (Waterwheel,Droseraceae) Populations

The genus Aldrovanda is a Palaeogene element containing a single extant species, Aldrovanda vesiculosa L. This aquatic carnivorous herb has a very wide range of distribution, natively covering four continents; however, it is a critically endangered aquatic plant species worldwide. Previous studies revealed that A. vesiculosa had an extremely low genetic variation. The main aim of the present paper is to explore, using chemometric tools, the diversity of 16 A. vesiculosa populations from various sites from four continents (Eurasia, Africa, Australia). Using chemometric data as markers for genetic diversity, we show the relationships of 16 A. vesiculosa populations from various sites, including four continents. Phytochemical markers allowed the identification of five well-supported (bootstrap > 90%) groups among the 16 populations sampled. The principal component analysis data support the idea that the strongly related African (Botswana) and Australian (Kimberley, NT, NW Australia) populations are the most distant ones, separated from the European and Asian ones. However, considering the five Australian populations sampled, three are nested within the Eurasian group. The chemometric data are correlated positively with the geographical distances between the samples, which suggests a tendency toward isolation for the most distant populations.     

中国喇叭螺属的系统发育关系和生物地理学初探(肺螺亚纲:柄眼目:虹蛹螺科)

本文运用支序分析方法和H enn ig86软件探讨了柄眼目虹蛹螺科喇叭螺属中国种类的系统发育关系。中国喇叭螺属种类现已知17种,主要分布于我国长江流域和秦岭以南的地区。选择H.tubif erum和G.hung erf ord ianus作为外群,运用命令ie*对原始数据集进行运算,并进行逐步加权处理,结果共得到步长=115,C I值=74,R I值=90的同等简约树2株,选择其中具有较少未解决系统关系的一株作为支序分析的首选支序图。支序分析的结果将中国喇叭螺属的17个种初步分为两组:喇叭螺组和贝喇叭螺组。贝喇叭螺组包括B.p licid ens和B.hubeina,喇叭螺组包括剩余的15种。该结果与J.T he le(1931)将喇叭螺属分为喇叭螺指名亚属和贝喇叭螺亚属相符。根据首选支序图,运用扩散-隔离分析方法对该属的动物地理学进行了分析和讨论,认为中国喇叭螺属现有分布格局的形成可能与青藏高原的隆起有关。     

Phylogenetic positions of two marine ciliates, Metanophrys similis and Pseudocohnilembus hargisi (Protozoa, Ciliophora,Scuticociliatia), inferred from complete small subunit rRNA gene sequences

The small subunit rRNA (SSrRNA) gene was sequenced for two marine scuticociliates Metanophrys similis and Pseudocohnilembus hargisi. The results show that this gene comprises 1763 and 1753 nucleotides in the two marine ciliates respectively. Metanophrys similis is phylogenetically closely related to the clade containing Mesanophrys carcini and Anophyroides haemophila, which branches basally to other species within the order Philasterida. Pseudocohnilembus hargisi groups with its congener, P. marinus, with strong bootstrap support. Paranophrys magna groups with the clade including Cohnilembus and Uronema, representing a sister clade to that containing the two Pseudocohnilembus species.     

Phylogenetic positions of two marine ciliates, Metanophrys similis and Pseudocohnilembus hargisi (Protozoa, Ciliophora, Scuticociliatia), inferred from complete small subunit rRNA gene sequences

The small subunit rRNA (SSrRNA) gene was sequenced for two marine scuticociliates Metanophrys similis and Pseudocohnilembus hargisi. The results show that this gene comprises 1763 and 1753 nucleotides in the two marine ciliates respectively. Metanophrys similis is phylogenetically closely related to the clade containing Mesanophrys carcini and Anophyroides haemophila, which branches basally to other species within the order Philasterida. Pseudocohnilembus hargisi groups with its congener, P. marinus, with strong bootstrap support. Paranophrys magna groups with the clade including Cohnilembus and Uronema, representing a sister clade to that containing the two Pseudocohnilembus species.     

Comparison of Molecular Biological Techniques (RAPD, ARDRA and SSrRNA Gene Sequencing) on the Phylogenetic Relationships of Lower Taxa within Spirotrichous Ciliates

The evolutionary relationships of seven spirotrichous ciliates (3 stichotrichs: Oxytricha saltans, O. Ferruginea, Stylonychia mytilus; 4 hypotrichs: Uronychia transfuga, Diophrys appendiculata, Aspidisca steini, Euplotes vannus) inferred from the SSrRNA (small subunit rRNA) gene sequences and the polymorphic patterns of RAPD (random amplified polymorphic DNA) and ARDRA (amplified ribosomal DNA restriction analyses) fingerprinting are constructed. Compared with that of morphometric characters, the dendrograms from SSrRNA gene using three different calculation methods (distance matrix, maximum-parsimony, and UPGMA) agree with the morphological division into two clades, Oxytricha - Stylonychia and Uronychia - Diophrys - Aspidisca - Euplotes, though the branching orders within the hypotrichous ciliates are slightly different from morphometric analyses.     

基于PsbA-trnH,RbcL和trnL-F序列的野生葡萄系统发育

采用PCR技术从湘西地区的3种野生葡萄中分离PsbA-trnH、RbcL和trnL-F基因片段,克隆至pMD18-T载体中测序,结合GenBank/EMBL/DDBJ中公布的其他葡萄科植物相应cpDNA基因信息,使用Mega4构建系统发育进化树,分析其系统发育关系.结果显示,PsbA-trnH,RbcL和trnL-F这3种cpDNA基因序列均能用于葡萄科属间的分子鉴定,但结果与传统形态学分类存在一些差异,RbcL能用于葡萄属内种间的分子鉴定.     

具腋生花序的异叶岩桐属一新记录种

描述了产自厄瓜多尔南部和秘鲁北部的热带地区片段化生境下的异叶岩桐属Monopyle一新种。本种与异叶岩桐属其他物种的重要区别在于其具有明显凸出的红色毛被以及腋生的花序,同时本种在过去十多年前采集到的标本中很少被发现,因此需要关注他的保护问题。     

角蝾螺精子的超微结构

用透射电镜(TEM)技术研究了角蝾螺精子的超微结构.成熟精子包括头部和尾部.头部由啤酒瓶状顶体与柱状细胞核构成.顶体内含物分布均匀,电子密度稍低于细胞核;顶体下腔呈细长管状,基部扩大成喇叭形,内有颗粒状物质分布.细胞核物质致密,电子密度高;核的前、后端都有一V字形凹陷,分别为核前窝和核后窝.尾部包括中段和末段.中段由5个线粒体围绕近、远端中心粒构成;末段细长鞭状,由中央轴丝及外包的质膜组成,轴丝为典型的"9+2"结构.比较了角蝾螺精子与相关腹足类精子结构的异同,分析了角蝾螺精子在腹足类系统演化中的地位.