染料木素及其钐配合物与DNA的相互作用

在合成染料木素钐（Ⅲ）配合物的基础上，以荧光光谱法、紫外吸收光谱法和粘度法研究了染料木素及其钐（Ⅲ）配合物与DNA的作用．结果发现，该配合物的荧光强度在加入DNA后增大，而染料木素则降低；配合物使DNA-EB体系的荧光强度降低要明显强于染料木素；配合物相较于配体与DNA相互作用之后，其紫外光谱的减色效应以及红移现象均强于配体；配合物使DNA粘度的增加的程度也大于配体．结果显示，染料木素及其钐（Ⅲ）配合物都能与DNA发生插入结合作用，但配合物与DNA结合得更加紧密．抗肿瘤活性体外测试的结果表明，无论染料木素还是配合物对于筛选的瘤株均具有一定的抑制作用，但是配合物对瘤株的抑制强于配体。     

Phylogeny and divergence of Chinese Angiopteridaceae based on chloroplast DNA sequence data （rbcL and trnL-F）

Marattioid ferns are an ancient lineage of primitive vascular plants that first appeared in the middle Carboniferous. Extant members are almost exclusively restricted to tropical regions, and the spe- cies-rich family Angiopteridaceae are limited in their distribution to the eastern hemisphere; relation- ships within the group are currently vague. Here the phylogenetic relationship between Angiopteris Hoffm. and Archangiopteris Christ et Gies. was evaluated based on the sequence analysis of chloro- plast rbcL gene and trnL-F intergenic spacer with MEGA2 and MrBayes v3.0b4. On the basis of the phy- logenetic pattern and fossil record, we further estimated the divergence time for the two genera. The phy- logenetic trees revealed that all species of Angiopteris and Archangiopteris in this study formed a monophyletic group with strong statistical support, but the relationship between the two genera re- mained unresolved based on individual sequence analysis. On the other hand, the sequence analyses of combined data set revealed that Archangiopteris species diverged first, indicating that Archangiop- teris may not be a direct derivative as traditionally assumed. The clade of Angiopteris and Archan- giopteris appears to have diversified in the late Oligocene (≈26 Ma) based on the molecular estimate. Thus, the evolutionary history of extant Angiopteris and Archangiopteris has been characterized by ancient origin and recent diversification, and these groups are not relic and endangered lineages as traditionally considered.     

4种植物多酚对生物大分子的保护作用

为了研究多酚类化合物对生物大分子氧化损伤的保护作用,采用MDA测定、SDSPAGE、琼脂糖电泳,检测了4种多酚对由自由基引起的脂质过氧化、蛋白质氧化降解、DNA断裂的保护作用.结果表明:槲皮素在抑制脂质过氧化中作用最突出,在保护蛋白质氧化降解中香草醛作用最强;芦丁在保护DNA的氧化性损伤中最有效.说明4种化合物在不同的抗氧化体系中有不同的活性.     

蓝藻分子系统学研究中常用的DNA序列

本文对近年来蓝藻分子系统学研究中常用的DNA序列进行了综述,分析了这些序列的特点和适用范围,并对蓝藻分子系统学的研究方法提出了自己的看法。     

对甲氧基苯甲醛为荧光探针测定DNA含量

基于DNA与对甲氧基苯甲醛的荧光猝灭效应,以甲氧基苯甲醛作为荧光探针建立了一种简便快速测定DNA的荧光分析方法.考察了pH、荧光探针浓度、温度、放置时间等条件对荧光探针及DNA测定的影响.该方法测定DNA含量的线性范围为51~1 000 ng/mL,检出限为30 ng/mL,10次测量500 ng/mL DNA的相对标准偏差为2.0%,可用于合成样品的测定.     

基于支持向量机和多层感知器的多病类诊断基因选择方法

超高维基因空间超小样本的基因选择问题是基因芯片技术的挑战性课题之一,对于解决维数发难问题和获得诊断基因具有重要的理论和实际意义.针对DNA微阵列数据的超高维空间和超小样本特性,提出了实现二病类样本有效分类的基于支持向量机(SVM)和leave-one-out的递增基因选择方法,并针对多病类情况的基因选择问题,提出了在区分两两病类所选基因基础上的基于多层感知器(MLP)和leave-one-out/MLP leave-4-out的递减基因选择方法.对于真实MIT数据(7129个基因、两个病类、72个样本)和NCI数据(2308个基因、64个样本、4个病类),用文中方法选择出了11个和6个诊断基因,与传统SNR方法的比较结果表明所选出的这些诊断基因有很好的诊断性能(即推广能力),既可有效诊断相应疾病,同时极大降低芯片和诊断费用,表明了该方法的有效性.     

利用分子遗传学方法探索新疆地区人类起源和迁徙模式

新疆地处亚、欧大陆交往联系的要冲地带,在研究人群进化、迁徙模式方面具有重要意义.大量的研究揭示:新疆地区现代人群是东西方人群混合的结果,支持此地区人类起源的混合学说,但对此仍有争议.文中对近年来新疆地区古代人群和现代人群的DNA遗传数据进行了综述,来探索东西欧亚对新疆古代人群和现代人群遗传结构的影响,并在考古学和体质人类学背景下对新疆青铜器时期和铁器时期的古代人群的来源和迁徙模式做出合理的预测,为今后新疆地区人群的遗传学研究指明方向.     

菠菜基因组DNA提取方法与条件的研究

分别采用CTAB、SDS、高盐低pH三种方法从菠菜叶片中提取基因组DNA,通过A260/A280值、A260/A230值和琼脂糖凝胶电泳对所提取的DNA进行定量、定性分析和综合比较。研究提取缓冲液用量、水浴时间、蛋白质沉淀剂(氯仿-异戊醇)用量、DNA沉淀剂(异丙醇)用量等条件对DNA提取效率和纯度的影响。并对CTAB法的提取条件进行了正交试验,优选出菠菜基因组DNA提取的适宜条件。     

试论发现DNA双螺旋结构的模型方法

DNA双螺旋结构模型的发现是20世纪生命科学最伟大的成就.本文从DNA双螺旋结构发现的角度,对模型方法的应用、意义和原则等进行论述和探讨.     

Functional analysis of the sbcD （dr1921 ） gene of the extremely radioresistant bacterium Deinococcus radiodurans

In eukaryotes, the Mre11-Rad50-Nbs1 (MRN) complex, which resides at the crossroads of DNA repair and checkpoint signaling, rapidly forms prominent foci at damage sites following double-strand break (DSB) induction. This complex carries out the initial processing of the DSB ends. Mutations in the genes that encode components of this complex result in DNA-damage hypersensitivity, genomic in- stability, telomere shortening, and aberrant meiosis. Therefore, the MR proteins are highly conserved during evolution. The bacterial orthologs of Mre11 and Rad50 are the SbcD and SbcC proteins, respec- tively. Deinococcus radiodurans, an extremely radioresistant bacterium, is able to mend hundreds of radiation-induced DSBs. The SbcD and SbcC proteins were identified as the products of the Dr1921 and Dr1922 genes. Disruption of the sbcD gene, by direct reverse-orientation insertional mutagenesis tech- nology, remarkably increases the cells’ sensitivity to various types of DNA damaging agents, such as ionizing radiation, ultraviolet irradiation, hydrogen peroxide, and mitomycin C. We also provide evidence that the drSbcD protein plays an important role in both growth and DNA repair in this organ- ism, especially in repair of DSBs generated after cellular exposure to 6000 Gy of IR. These results demonstrate that the drSbcD protein plays an important role in DSBs repair in D. radiodurans.