高亲和力PO4(3-)转运子编码基因的cDNA克隆及特性分析

以简并引物，利用RT -PCR，克隆了普通小麦和黑麦根系的PO 43-转运子( Trans-porter)基因长约1.2kb的部分cDNA序列。对其与GenBank中的已知序列进行同源性比较，结果表明：(1)小麦与拟南芥、番茄等高等植物的氨基酸水平的同源性为60%～78%; (2)与酵母较低为40%左右，而与丝状真菌和细菌的同源性则<27%; (3)小麦与黑麦的同源性为75%。对其表达特性的研究表明：(1)该基因在根系和茎叶组织中均有表达，但在根系组织中转录产物的累积量显著高于茎叶;(2)磷饥饿条件下，茎叶和根系组织中该基因的表达均增强，但根系组织中增强幅度较大，由此认为该基因产物的功能不只是根系从生长环境中吸收PO 43-，而与PO 43-在植物体内的转运密切相关;(3)磷饥饿5天 后的植株重新供给充足的PO 43-，则该基因的表达在24小时内即显著减弱;(4)分根试验中同株的部分根系生长于磷饥饿(OuM)环境中，而另一部分根系生长于PO 43-充足(250uM)的环境中，这两部分根系中该基因转录产物的积累水平并无显著差异。因此认为植物感受磷饥饿胁迫的信号可能来自植物体内部POi-库的耗竭。此外，用磷讥饿条件下的普通小麦根系mRNA构建了cDNA文库，以克隆的部分序列为探针，从cDNA文库中分离了全长序列。

Two genera of freshwater Dinophyta newly recorded from China

A re-examination under the phase contrast microscope of a collection made in a small lake in Xizang, China, which had been previously referred to Glenodinium gymnodinium Penard, has shown that the cell wall is composed of numerous usually hexagonal platelets, and thus the species should be a relatively common member of the genus Woloszynskia, namely W. tenuissima (Lauterborn) Thompson. Tetradinium intermedium Geitler is an immobile species collected from a small pond in Wuhan City, Hubei Province, China. It was attached on filaments of an Oedogonium species. Both genera are newly recorded in China.

甲壳单糖、寡糖、低聚糖制备方法的优化与比较研究

该文通过大量实验,确定了制备单糖、寡糖及低聚糖的最佳生产工艺,并对几种制备方法做了比较研究.该文采用氧化降解和微波降解等不同技术对甲壳低聚糖的制备工艺进行了研究.H<,2>O<,2>作为氧化剂,在酸性条件下,采用4因素3水平进行正交实验,得到了制备分子量2000以下的寡糖的最佳条件.微波降解制备低聚糖目前尚未见报道,经过该实验证明此方法可降低能耗,减小污染,节省时间和原料,是一个具有产业化前景和市场潜力的好方法.通过以不同的壳聚糖为原料,探讨了在微波场作用下纯溶剂及盐效应对分子量变化的影响,最终产物的分子量均在1×10<'5>～10×10<'5>之间.根据IR光谱,壳聚糖降解前后主要峰的位置都无变化,只是随壳聚糖相对分子质量的降低各峰峰强有所变化,证明了壳聚糖氧化降解及微波降解制备寡糖、低聚糖是以开裂壳聚糖的β-1.4糖苷键来进行.该项研究对更好的开发利用甲壳质资源,促进中国海洋生物制品的发展具有十分重要的意义.

Cytological and Molecular Identification of Alien Chromatin in Giant Spike Wheat Germplasm

Alien chromosomes of twelve giant spike wheat germplasm lines were identified by C-banding, genomic in situ hybridization (GISH), sequence characterized amplified region (SCAR), and random amplified polymorphic DNA (RAPD). All lines showed a chromosome number of 2n = 42, five of them carried both a pair of wheat-rye (Triticum aestivum-Secale cereal) 1BL/1RS translocation chromosomes and a pair of Agropyron intermedium (Ai) chromosomes, three carried a pair of Ai chromosomes only, three others carried a pair of 1BL/1RS chromosomes only, and one carried neither 1BL/1BS nor Ai chromosome. Further identification revealed that the identical Ai chromosome in these germplasm lines substituted the chromosome 2D of common wheat (Triticum aestivum L.), designated as 2Ai. The genetic implication and further utilization of 2Ai in wheat improvement were also discussed.