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.     

Identification of quantitative trait loci affecting tolerance to low phosphorus in rice (Oryza Sativa L.)

Phosphorus (P)-deficiency in rice (Oryza. Sativa. L) may cause yield reductions. This research has been conducted to map quantitative trait loci (QTLs) for tolerance to low phosphorus stress in a doubled haploid (DH) population. By using the linkage map of this population, the QTLs for relative dry weight, relative P content and relative P utilization efficiency have been located. The results indicate that one RFLP marker located on chromosome 6 is closely associated with relative root dry weight, relative shoot dry weight and relative total dry weight, which explain 24.9%, 20.5% and 25.2% of the total phenotypic variations, respectively. Two QTLs affect relative P uptake content, which account for 20.7% of the total phenotypic variations. One micro-effect QTL has been found to be associated with relative P utilization efficiency. It is suggested that the P uptake efficiency is more associated with P efficiency. Among the secondary physiological indices of P uptake efficiency, the root dry weight is more important than others.     

Cell surface clustering of Cadherin adhesion complex induced by antibody coated beads

Cadherin receptors mediate cell-cell adhesion, signal transduction and assembly of cytoskeletons. How a single transmembrane molecule Cadherin can be involved in multiple functions through modulating its binding activities with many membrane adhesion molecules and cytoskeletal components is an unanswered question which can be elucidated by clues from bead experiments. Human lung cells expressing N-Cadherin were examined. After co-incubation with anti-N-Cadherin monoclonal antibody coated beads, cell surface clustering of N-Cadherin was induced. Immunofluorescent detection demonstrated that in addition to Cadherin, β-Catenin, α-Catenin, α-Actinin and Actin fluorescence also aggregated respectively at the membrane site of bead attachment. Myosin heavy chain (MHC), another major component of Actin cytoskeleton, did not aggregate at the membrane site of bead attachment. Adhesion unrelated protein Con A and polylysine conjugated beads did not induce the clustering of adhesion molecules. It is indicated that the Cadherin/Catenins/α-Actinin/Actin complex is formed at Cadherin mediated cell adherens junction; occupancy and cell surface clustering of Cadherin is crucial for the formation of Cadherin adhesion protein complexes.     

Identification of quantitative trait loci affecting tolerance to low phosphorus in rice (Oryza Sativa L.)

Phosphorus (P)-deficiency in rice (Oryza.Sativa.L) may cause yield reductions.This research has been conducted to map quantitative trait loci (QTLs) for tolerance to low phosphorus stress in a doubled haploid (DH) population.By using the linkage map of this population,the QTLs for relative dry weight,relative P content and relative P utilization efficiency have been located.The results indicate that one RFLP marker located on chromosome 6 is closely associated with relative root dry weight,relative shoot dry weight and relative total dry weight,which explain 24.9%,20.5% and 25.2% of the total phenotypic variations,respectively.Two QTLs affect relative P uptake content,which account for 20.7% of the total phenotypic variations.One micro-effect QTL has been found to be associated with relative P utilization efficiency.It is suggested that the P uptake efficiency is more associated with P efficiency.Among the secondary physiological indices of P uptake efficiency,the root dry weight is more important than others.     

基于异型网的数据通信和共享

本文主要介绍基于 Unix- Windows异型网环境下点对点通信的一种方法 ,通过它可以实现 Unix服务器、终端与 Windows工作站及 Windows NT服务器间点对点通信。此外还介绍了一种在 Unix- Net Ware- Windows- Windows NT- L ANMAN工作站异型网环境下文件资源共享方法。通过它可实现 Windows工作站及 Windows NT服务器及 L ANMN工作站对 Unix文件服务器及Novell文件服务器的资源共享。     

计算芳烃摩尔体积的新方法——基团键贡献法

根据分子中基团的特性和连接性,发展了一种计算芳烃摩尔体积的新方法——基团键贡献法,该方法将基团贡献法和化学键贡献法有机地结合在一起,既考虑分子中基团的特性,又考虑基团间的连接性(化学键),同时具有基团贡献法和化学键贡献法的特点。应用基团键贡献法对211种芳烃摩尔体积的计算结果表明,计算值十分接近实验值,平均误差0.354％,计算精度显著优于文献方法。     

铁矿球团有机粘结剂的分子构型及选择判据

为开发有效的铁矿球团有机粘结剂 ,需要建立系统的粘结剂结构与性能关系理论 .为此 ,提出了理想的有机粘结剂分子构型 (X—P—K) .通过实例 ,计算了极性基团COO- 及亲水基团O- 的电负性 ,初步确定了极性基团及亲水基团的选择判据 ;对粘结剂有机链架结构与性能的关系进行了定性分析 ,认为选择环形网状结构的链架较为理想 .根据分子结构的理想模型及选择判据 ,研制合成了新型粘结剂S 1 .造球试验结果表明 ,此粘结剂性能优良 ,干球强度为 32 2 .8N 个 ,落下强度为 1 6 .8m 次 ,生球爆裂温度为 82 0℃ ,克服了有机粘结剂热稳定性差的缺陷 .     

基于ARX环境下图形数据库的设计

描述了在ARX环境下用C 操作AutoCAD图形数据库的方法。图形数据库是连接系统数据库与图形显示的桥梁。由于ARX可分享AutoCAD的地址空间并直接调用AutoCAD动态链接库 ,因而使得操作AutoCAD图形数据更加方便     

低聚香豆胶交联凝胶体系

首次研究了微波辅助酸降解香豆胶过程及其影响因素,并与水浴酸降解过程进行对比,获得了低聚香豆胶。研究了低聚香豆胶与硼砂交联形成凝胶的过程,考察了低聚香豆胶浓度、硼砂浓度和pH值对形成凝胶体系的影响,获得了稳定的凝胶体系。进一步研究了低聚香豆胶凝胶体系的流变特性。结果表明：微波辅助酸降解法是快速降解香豆胶的新方法,降解速度显著高于水浴酸降解法。在适当的碱性条件下,低聚香豆胶可与硼砂形成较稳定的交联凝胶体系,该体系具有显著的粘弹性和剪切变稀特性。     

热聚合法制备二苯甲酰-L-酒石酸手性分子印迹聚合物Ⅰ.热聚合条件的优化

以二苯甲酰-L-酒石酸(L-DBTA)为模板分子,甲基丙烯酸甲酯(MMA)等为功能单体,乙二醇二甲基丙烯酸酯(GDMA)为交联剂,采用热聚合方法合成了L-DBTA手性分子印迹聚合物(ML-DBTA),讨论了不同功能单体、功能单体的用量、交联剂的用量、聚合温度、聚合时间、溶剂等对ML-DBTA合成的影响.通过ML-DBTA对底物的结合实验和高效液相色谱分析,合成的ML-DBTA对模板分子L-DBTA具有很好的识别性,对L-DBTA的选择性比二苯甲酰-D-酒石酸(D-DBTA)高,其分离因子(α)可达2.79.优化的热聚合条件为n(L-DBTA)n(MMA)n(GDMA)=1420,聚合温度60℃,聚合时间48 h,溶剂为乙腈.