CpG DNA enhances the immune responses elicited by the DNA vaccine against foot-and-mouth disease virus in guinea pigs

CpG DNA is DNA sequence that has immune stimulatory effects. Several lines of investigation over the past few years indicate that CpG DNA plays an important role in the induction of immune responses to DNA vaccines. In this study, CpG DNA-containing synthetic oligodeoxynucleotide (CpG-ODN) was cloned into the eukaryotic expression plasmid encoding a fusion protein containing b- galactosidase from E. coli and immunogenic epitopes of foot- and-mouth disease virus (FMDV) type O, and the immune responses induced by the plasmid were assayed. The results showed that guinea pigs immunized with the recombinant plasmid containing CpG-ODN generated a higher level of FMDV-neutralizing antibody and a stronger T cell proliferative response and protection against viral challenge than those receiving the plasmid containing no CpG-ODN. Our study demonstrated that it is an effective route to enhance the efficacy of DNA vaccines by inserting exogenous CpG DNA into the plasmids, and the DNA vaccine developed here is a promising candidate to prevent FMDV infection.     

Applications of14C-AMS in biomedical sciences (Bio-14C-AMS)

Accelerator mass spectrometry (AMS) is an ultrasensitive measure for tracing¹⁴C labeled moleculesin vivo or detecting the biomarker for assessment of carcinogenesis. In this review, basic principles, wide applications and new progresses of¹⁴C-bio-AMS are presented. It has been a new advanced tool for measuring the adduction of biologcial molecules with xenobiotics, including carcinogens, drugs, agrochemicals, nicotine, etc. The successful applications have proven the effectiveness of AMS to assessing cancer risk, screening drug toxicity and studying nutrients uptake. In particular, AMS is characterized by measuring xenobiotics at very low dose levels relevant to human environmental exposure. It is sensitive and precise to an attomole (10⁻¹⁸ mole) or less of¹⁴C per mg carbon. Although it has some shortcomings, undoubtedly, AMS possesses an evident merit of high sensitivity and will have widespread applications in the biomedical sciences.     

甲醛致斜纹夜蛾SL-1细胞DNA损伤作用的研究

为了研究甲醛致昆虫细胞DNA-蛋白质的交联作用（DNA—protein crosslinks,DPC）和DNA的断裂作用,以斜纹夜蛾SL-1细胞为材料,采用KCI-SDS沉淀法和彗星实验来检测液态甲醛染毒后SL-1细胞中DPC的含量及DNA的断裂效应．KCISDS沉淀法的结果表明,低浓度的液态甲醛（25μmol／L,125μmol／L）不能引起DPC,较高浓度（625μmol／L）可以引起明显的DPC（P〈0．01）;而彗星实验的结果则显示甲醛在低浓度（5μmol／L,25μmol／L）时可以引起DNA链的断裂（P〈0．01）,在较高浓度（625μmol／L）时尾部DNA％和尾矩比空白对照显著降低（P〈0．01）,表明此时甲醛所致的DPC掩盖了DNA断裂的作用．结论是甲醛在较高浓度时可以导致明显的DPC作用,而在低浓度时以DNA断裂为主．     

Sm(Ⅲ)-HP配合物与DNA的作用机制

 应用紫外-可见光谱法和荧光光谱法并以中性红(NR)作光谱探针研究了Sm(Ⅲ)HP配合物与DNA的作用机制。研究表明,血卟啉(HP)与Sm(Ⅲ)的配合比n_Sm(Ⅲ)∶n_HP = 1∶ 1,Sm(Ⅲ)HP配合物与DNA的结合比n_Sm(Ⅲ)HP ∶ n_DNA = 1∶ 1,Sm(Ⅲ)HP配合物与DNA的结合常数K^θ_30℃ = 1.67×10⁴  L/mol。该过程为熵所驱动,其Δ _r H_m为4.86×10⁴ J/mol,Δ_r S_m为195.61 J/(mol·K),30 ℃时Δ_r G_m为－1.06×10⁴ J/mol。Scatchard法和探针法研究表明,Sm(Ⅲ)HP与DNA之间的结合方式主要是沟区作用。     

导入大豆总DNA改良大麦籽粒营养品质

利用花粉管通道法和基因枪法将大豆总DNA直接导入大麦。采用微量凯氏定氮法和氨基酸自动分析仪进行大麦后代籽粒蛋白质含量和氨基酸含量分析。结果显示：(1)经花粉管通道法导入大豆总DNA获得的大麦后代有6个单株籽粒蛋白质含量明显超过对照(12．91％)，它们是18．23％，16．61％，16．42％，16．58％，16．22％和16．38％，占总数比例的7．06％；(2)经基因枪法导入大豆总DNA共获得12个单株籽粒蛋白质含量明显超过对照(13．29％)，它们的蛋白含量分别为16．70％，16．52％，17．9l％，19．59％，17．44％，18．56％，18．46％，17．3l％，16．5l％，18．8l％，18．8l％和19．02％，占总数比例的8．33％；(3)籽粒氨基酸含量分析显示在高蛋白变异后代中，随着籽粒蛋白质含量增加的同时，籽粒总氨基酸和各种必需氨基酸含量也有明显提高．经直线相关分析显示，导入大豆总DNA的后代籽粒赖氨酸等6种必需氨基酸含量与总氨基酸含量呈极显著正相关关系。本试验结果充分说明，直接导入大豆总DNA有可能提高大麦籽粒的蛋白质含量及质量。     

Environmental chemical stressors as epigenome modifiers: a new horizon in assessment of toxicological effects

In eukaryotic cells, chromatin transformation from euchromatin into heterochromatin as a means of controlling gene expression and replication has been known as the ‘‘accessibility hypothesis' '. The interplay of epigenetic changes including histone modifications, DNA methylation, RNA interference(RNAi) and other func- tional epigenetic components are intricate. It is believed that these changes are well-programmed, inherited and can be modified by environmental contaminant stressors. Environmentally-driven epigenetic alterations during development, e.g. embryonic, foetal or neonatal stage, may influence disease susceptibility in adulthood. Therefore, understanding how epigenome modifications develop in response to environmental chemicals and, how epigenetic-xenobiotic interactions influence human health will shed new insights into gene-environment interactions in the epidemiology of several diseases including cancer. In this review, we consider studies of chemical modifiers including nutritional and xenobiotic effects on epigenetic components in vitro or in vivo. By examining the most-studied epigenome modifications and how their respective roles are interlinked, we highlight the central role of xenbiotic- modified epigenetic mechanisms. A major requirement will be to study and understand effects following environmentally-relevant exposures. We suggest that the study of epigenetic toxicology will open up new opportunities to devise strategies for the prevention or treatment of at-risk populations.     

基于PFP荧光共振能量转移原理检测氧化损伤DNA

提出一种基于水溶性共轭聚合物PFP荧光共振能量转移原理检测氧化损伤DNA的方法。通过加入DNA修复酶来识别并切除被氧化的DNA碱基,获得含磷酸基团核苷酸空隙的DNA,再通过羟基引入荧光标记物,加入PFP后可得到PFPDNA复合物,通过荧光共振能量转移(fluorescence resonance energy transfer,FRET)进行氧化损伤DNA的检测。对方法的影响因素进行了考查和优化,包括PFP的浓度、DNA修复酶的种类、DNA聚合酶I的用量以及芬顿反应的时间等。研究表明,基于PFP荧光共振能量转移原理检测氧化损伤DNA方法具有灵敏度高和特异性强的优势,可确保检测的准确性,对老年疾病的预防医学具有很好的应用前景。     

DNA分子电荷输运的大极化机制探讨

近年来研究发现,与生命体密切相关的DNA损伤与修复过程伴随着DNA链内电荷的转移.在DNA中,极化子是重要的元激发,是DNA中电荷传递可能的载流子.为了更好的理解DNA的电荷输运的极化子机制,给出了能够准确估计电声耦合常数α数值的理论方法.利用确定的电声耦合常数α,计算了极化子宽度和极化子束缚能.计算结果显示,DNA中的电荷输运是通过大极化子的相干运动来实现的.     

不同花色金盏菊的RAPD分析

利用RAPD分析技术,选取13个具有10个碱基长度的随机引物,对开淡黄色花和橙色花的金盏菊进行了扩增反应,在对扩增产物进行琼脂糖电泳后显示：有9个随机引物扩增出条带,一共扩增出条带89条,平均每个随机引物扩增约10条,在9个随机引物中,有3个引物扩增的条带在两种不同花色金盏菊中有差异,此项研究结果将为分析控制淡黄色和橙色花色有关的基因提供一点新的思路。     

p53-dependent upregulation of PIG3 transcription by γ-ray irradiation and its interaction with KAP1 in responding to DNA damage

PIG3 (p53-inducible gene 3), originally identified as one of a set of genes induced by p53 before the onset of apoptosis, was assumed to contribute to early cellular response to DNA damage. Here, we studied the relation between p53 status and the increased expression of PIG3 by ionizing radiation (IR), and the related clues regarding the involvement of PIG3 in the cellular response to IR-induced DNA damage signaling. We demonstrated that the pentanucleotide microsatellite sequence was responsible for the p5...