DNA生物大分子的动力学特性与生物功能(Ⅱ)

对ＤＮＡ中激发的孤立子进行了分类，同时也研究了它的一些特点．我们着重研究了用此理论解释ＤＮＡ的基本生物功能──复制和转录及遗传与变异等问题．     

寡聚核苷酸研究进展

对寡聚核苷酸近年来在化学及生物医学等领域的研究进展进行了比较全面的介绍,包括寡聚核苷酸片断与蛋白质、药物的相互作用以及反义寡聚核苷酸的研究进展及应用前景等。     

乳糖诱导Pfu DNA聚合酶基因的表达及酶的纯化

利用乳糖诱导重组大肠杆菌BL21(DE3)中Pfu DNA聚合酶基因的表达。对诱导菌株起始生长量、乳糖浓度和诱导持续时间进行了优化,尝试使用JK110弱阳离子交换柱和Sephadex G-75凝胶层析柱来分离纯化Pfu DNA聚合酶,并用PCR扩增实验检测酶活性。结果表明乳糖可以有效诱导Pfu酶的表达,JK110离子交换柱有较好的纯化效果,从500 mL培养液中可以得到3×105U的酶活,比活达22,200 U/mg,结果好于IPTG诱导表达。     

运动、氧化应激与DNA损伤和修复

在分子和基因水平上对运动时氧化应激损伤、氧化应激与DNA损伤以及DNA损伤和修复等几方面关系进行探讨,旨在探讨运动疲劳和损伤发生的分子生物学基础,并对未来运动医学研究的发展趋势进行展望。     

Fungal diversity in adult date palm (Phoenix dactylifera L.) revealed by culture-dependent and culture-independent approaches

Endophytic flora plays a vital role in the colonization and survival of host plants, especially in harsh environments, such as arid regions. This flora may, however, contain pathogenic species responsible for various troublesome host diseases. The present study is aimed at investigating the diversity of both cultivable and non-cultivable endophytic fungal floras in the internal tissues (roots and leaves) of Tunisian date palm trees (Phoenix dactylifera). Accordingly, 13 isolates from both root and leaf samples, exhibiting distinct colony morphology, were selected from potato dextrose agar (PDA) medium and identified by a sequence match search wherein their 18S–28S internal transcribed spacer (ITS) sequences were compared to those available in public databases. These findings revealed that the cultivable root and leaf isolates fell into two groups, namely Nectriaceae and Pleosporaceae. Additionally, total DNA from palm roots and leaves was further extracted and ITS fragments were amplified. Restriction fragment length polymorphism (RFLP) analysis of the ITS from 200 fungal clones (leaves: 100; roots: 100) using HaeIII restriction enzyme revealed 13 distinct patterns that were further sequenced and led to the identification of Alternaria, Cladosporium, Davidiella (Cladosporium teleomorph), Pythium, Curvularia, and uncharacterized fungal endophytes. Both approaches confirmed that while the roots were predominantly colonized by Fusaria (members of the Nectriaceae family), the leaves were essentially colonized by Alternaria (members of the Pleosporaceae family). Overall, the findings of the present study constitute, to the authors’ knowledge, the first extensive report on the diversity of endophytic fungal flora associated with date palm trees (P. dactylifera).     

美味猕猴桃基因组DNA的提取条件优化

采用改良CTAB法以及不同2-巯基乙醇梯度和不同EDTA梯度分离基因组DNA的方法对多糖含量高、极易褐化的美味猕猴桃嫩叶基因组DNA提取条件进行了优化：结果表明，提取缓冲液中加入20mmol／LEDTA及4％、5％β-巯基乙醇的改良CTAB法和40mmol／L、60mol／L、80mmol／L、100mmol／LEDTA及不同浓度的β-巯基乙醇(0％～5％)的改良CTAB法提取效果都比较好。     

口腔脱落细胞DNA检验在刑事案件中的应用

报道了3起利用口腔脱落细胞成功进行DNA检验的案例,并对其中一些事项进行了探讨。这些案例表明,口腔脱落细胞DNA检验可以在刑事案件中发挥重要的作用。     

Evaluation of the antioxidant effects of four main theaflavin derivatives through chemiluminescence and DNA damage analyses

Theaflavins (TFs) are the dimers of a couple of epimerized catechins, which are specially formed during black tea fermentation. To explore the differences among four main TF derivatives (theaflavin (TF₁), theaflavin-3-gallate (TF₂A), theaflavin-3′-gallate (TF₂B), and theaflavin-3,3′-digallate (TF₃)) in scavenging reactive oxygen species (ROS) in vitro, their properties of inhibiting superoxide, singlet oxygen, hydrogen peroxide, and the hydroxyl radical, and their effects on hydroxyl radical-induced DNA oxidative damage were systematically analyzed in the present study. The results show that, compared with (−)-epigallocatechin gallate (EGCG), TF derivatives were good antioxidants for scavenging ROS and preventing the hydroxyl radical-induced DNA damage in vitro. TF₃ was the most positive in scavenging hydrogen peroxide and hydroxyl radical, and TF₁ suppressed superoxide. Positive antioxidant capacities of TF₂B on singlet oxygen, hydrogen peroxide, hydroxyl radical, and the hydroxyl radical-induced DNA damage in vitro were found. The differences between the antioxidant capacities of four main TF derivatives in relation to their chemical structures were also discussed. We suggest that these activity differences among TF derivatives would be beneficial to scavenge different ROS with therapeutic potential.     

基于三链DNA结构的全错位排列问题算法

目前,一种新型的DNA计算模型——三链DNA计算模式正越来越受到人们的关注。已经证实,DNA单链能在RecA蛋白的介导下与同源的双链DNA匹配成稳定的三链DNA结构,利用此三链核酸提取目的DNA序列是完全可行的。文章提出了全错位排列问题的基于三链DNA的计算模型,由于表示可能解的链都是双链,彼此不会错配,也不会形成发夹结构,这样就大大降低了编码复杂度和计算错误率。     

DNA序列数形表示的研究

DNA序列的数形表示是用数学方法和计算机处理方法分析生物分子序列首先要解决的问题。序列表示的优劣会对最终分析结果有直接的影响。本文介绍了现有几种DNA序列数形表示方法。