铽（Ⅲ）探针法研究一些金属离子与DNA的作用

本文首次选用Ｔｂ（Ⅲ）作为荧光探针，研究了ｃｄ（Ⅱ）、Ｚｎ（Ⅱ）、Ｃａ（Ⅱ）、Ｍｇ（Ⅱ）与ＤＮＡ反应的结合部位。结果表明：Ｃｄ（Ⅱ）、Ｚｎ（Ⅱ）在ＤＮＡ上有两种结合部位，即ＤＮＡ双螺旋外侧的磷酸基和内侧的碱基鸟漂呤上的Ｎ－Ｔ。而ｃａ（Ⅱ）、Ｍｇ（Ⅱ）在ＤＮＡ上只有一个结合部位即磷酸基。说明Ｔｂ（Ⅲ）不仅可以作为ＤＮＡ构象及ＤＮＡ单链成分、不配对碱基残余的探针，而且可以用它探测一些金属离子与ＤＮＡ反应的结合部位。     

脱氧核糖核酸与双苯甲亚胺相互作用的荧光特性研究

采用荧光光谱法对脱氧核糖核酸（ＤＮＡ）与双苯甲亚胺（Ｈｏｃｅｈｓｔ ３３２５８）相互作用的方式及其作用机理进行了研究,证实了Ｈｏｅｃｈｓｔ ３３２５８与ＤＮＡ的相互作用除嵌入作用时,还存在持异性的静电作用;Ｈｏｅｃｈｓｔ３３２５８与ＤＮＡ主要作用在Ａ－Ｔ匹配,同时,在磷酸根的存在下可以减弱Ｈｏｅｃｈｓｔ３３２５８与ＤＮＡ的非特异性作用。另外,根据荧光峰增强与Ｈｏｅｃｈｓｔ３３２５８浓度的线性关系,     

2,9-二甲基-1,10-菲咯啉的dl-丙氨酸衍生物的合成表征及其镧(Ⅲ)配合物与 DNA作用光谱研究

以２,９－二甲基－１,１０－菲咯啉为初始原料,合成了２,９－二甲基－１,１０－菲咯啉的ｄｌ－丙氨酸衍生物：１,１０－菲咯啉－２,９－二亚甲基亚氨基－（２,２’－二甲基）二乙酸（Ｌ）。该配体经过元素分析。红外光谱、核磁共振氢谱表征。在 ２５±０．１℃、 Ｉ＝ ０．１ｍｏｌ·ｄｍ~（－３）ＮａＮＯ_３的条件下,用ｐＨ电位滴定法测定了该配体的质子化常数及其与Ｌａ（Ⅲ）的配合物的稳定常数。通过电子光谱研究了Ｌｂ（Ⅲ）的配合物与小牛胸腺 ＤＮＡ的相互作用。用溴化乙锭作为荧光探针研究了 Ｌａ（Ⅲ）－Ｌ配合物与小牛胸腺 ＤＮＡ的相互作用的过程。作为对比,也研究了 Ｌａ（Ⅲ）分别与１,１０－菲咯啉（Ｐｈｅｎ）、 ｄｌ－丙氨酸（ Ａｌａ）的配合物与小牛胸腺 ＤＮＡ的相互作用。结果表明 Ｌａ（Ⅲ）－Ｌ配合物与小牛胸腺ＤＮＡ作用既有共价键合,又有插入作用。     

高序热解石墨与玻碳电极上DNA的氧化和吸附行为

在高序热解石墨（ＨＯＰＧ）电极上,采用微分脉冲伏安法（ＤＰＶ）和电化学原子显微镜法（ＥＣＡＦＭ）探究小牛胸腺ＤＮＡ（ＣＴ ＤＮＡ）在电极表面的吸附。实验发现,控制电位下预极化对双链ＤＮＡ和ＨＯＰＧ电极上的吸附有很大的影响。而对单链ＤＮＡ影响不大。实验表明,在ＨＯＰＧ电极上ＥＡＦＭ是ＤＮＡ研究领域十分有用的技术,根据ＡＦＭ图象,结合文献上的ＤＮＡ吸附模型提出了ＣＴ ＤＮＡ研究领域十分有用的技术,根据     

单链脱氧核糖核酸在石墨电极表面固定化的研究

用５％（Ｖ／Ｖ）３－氨基丙基三乙氧基硅烷（ＰｒＮＨ２硅烷Ⅱ）在石墨电极表面硅烷化以导入氨基（－ＮＨ２）,然后用乙基－（３－二甲基丙基）碳二亚胺盐要卤）ＥＤＣ）关活化剂,将单链ＤＮＡ（共价固定在石墨电极表面。采用显微分光光度法、红外光谱法和电化学方法对电极表面的ｓｓＤＮＡ层进行了表征,并用紫外－可见光谱法对电极表面固定化ｓｓＤＮＡ的杂交特性进行了研究。结果表明,ｓｓＤＮＡ可以比较均匀地固定在石墨电极     

稀土-8-羟基喹啉-核酸体系的荧光特性

报道了钪、钇、镧等三价离子在核酸存在下与８羟基喹啉（８ＨＱＬ）形成三元体系的荧光特性，对比核酸和稀土离子的种类对荧光发射的影响。结果表明有鱼精子ＤＮＡ（ＤＮＡｆｓ）＞小牛胸腺ＤＮＡ（ＤＮＡｃｔ）＞酵母ＲＮＡ（ＲＮＡｙ）的荧光增强顺序；稀土离子与８ＨＱＬ的摩尔比随稀土离子的种类发生变化，与ＲＥ３＋８ＨＱＬ配合物的摩尔比有较大差异。     

DNA电化学传感器在DNA片段识别与测定中的应用

本文用乙基－（３－二甲基丙基）碳二亚胺盐酸盐（ＥＤＣ）和羟基丁二酰亚胺（ＮＨＳ）活化已被氧化的石墨电极,然后将单链ＤＮＡ（ｓｓＤＮＡ－１）固定在石墨电极上。运用核酸杂交技术,使具有电化学活性的染料Ｈｏｅｃｈｓｔ ３３２５８ 嵌入双链ＤＮＡ 分子（ｄｓＤＮＡ）的碱基对中,在石墨电极表面形成ｄｓＤＮＡ－Ｈｏｅｃｈｓｔ ３３２５８ 层,通过伏安法测定嵌入Ｈｏｅｃｈｓｔ ３３２５８的氧化峰电流,可以识别和测定溶液中互补的ｓｓＤＮＡ－２ 片段,ｓｓＤＮＡ－２ 的浓度在４．８×１０－ ５～１．１×１０－ ７ ｍ ｇ／ｍ Ｌ范围内,有线性关系,检测限可达６．０×１０－ ８ ｍ ｇ／ｍ Ｌ。     

钌联吡啶络合物与脱氧核糖核酸分子相互作用的荧光光谱研究与？…

合成了２苯基（４－溴）咪唑「ｆ」邻菲咯啉（简称ＰＩＰⅢ）新的配体及「Ｒｕ（ｂｐｙ）２ＰＩＰ（Ⅲ）」＾２＋新的络合物,用荧光光谱研究了络合物与小牛胸腺ＤＮＡ分子的结合情况,在ｐＨ７．４,络合物与ＤＮＡ作用后,在５８７ｎｍ（λｅｘ＝４７１ｎｍ）产生很强的荧光峰,其发光强度与ＤＮＡ浓度呈线性关系;     

N-β-萘酚醛-D-氨基葡萄糖席夫碱金属配合物与DNA作用的谱学研究

合成了Ｎ－β－萘酚醛－Ｄ－氨基葡萄糖席夫碱（Ｃ１７Ｈ１９Ｏ６Ｎ,简写为ＮＧ）的Ｃｕ（Ⅱ）、Ｚｎ（Ⅱ）、Ｎｉ（Ⅱ）、Ｆｅ（Ⅱ,Ⅲ）、Ｃｏ（Ⅱ,Ⅲ）金属配合物,并用电子吸收光谱、荧光光谱、表面增强拉曼光谱研究了它们与ＤＮＡ的相互作用。探讨了这们与ＤＮＡ的作用方式,发现具有萘环结构的化合物与ＤＮＡ容易发生插入作用,其中Ｃｕ（Ⅱ）ＮＧ,Ｆｅ（Ⅱ）ＮＧ,Ｆｅ（Ⅱ）ＮＧ,Ｃｏ（Ⅱ）ＮＧ,Ｃｏ（Ⅲ）ＮＧ作为抗癌药物有进一步研究的价值。     

DNA分子结构的多态性研究 (Ⅱ) 吖啶橙凝聚体变化诱导的质粒DNA大分子构象的研究

利用吸收光谱和荧光光谱方法,研究了吖啶橙（ＡＯ）与质粒ＤＮＡ水溶液、以及含胶束介质的吖啶橙与质粒ＤＮＡ溶液体系的相互结合作用及减色效应。结果表明：吖啶橙对质粒ＤＮＡ的吸收光谱有减色效应;含十二烷基硫酸钠（ＳＤＳ）的ＡＯ水溶液体系中,随着ＳＤＳ浓度的增加,其光谱结果表现为由凝聚态向单体的转化。而在含十二烷基硫酸钠（ＳＤＳ）的ＡＯ与质粒ＤＮＡ溶液体系中,吖啶橙凝聚态随ＳＤＳ浓度的增加,对ＡＯ与质粒ＤＮＡ相互结合产生协同的减色效应,使质粒ＤＮＡ空间结构发生缩拢。进一步采用电泳法研究了ＡＯ凝聚态可能对质粒ＤＮＡ构象的影响,结果表明：在ＡＯ与质粒ＤＮＡ溶液体系中,ＡＯ浓度的增加对质粒ＤＮＡ构象未产生影响;而在含有ＳＤＳ的ＡＯ与质粒ＤＮＡ的溶液体系中,由于ＳＤＳ对ＡＯ凝聚态的解聚作用,以及ＳＤＳ对质粒ＤＮＡ减色效应的协同作用,使得质粒ＤＮＡ的构象发生变化,诱导质粒ＤＮＡ形成超螺旋构象     

DNA/CdS纳米粒子复合体系的光谱和光电化学性质

在水溶液中以DNA作为模板和稳定剂, 构筑了DNA与CdS纳米粒子复合体系(DNA/CdS NPC), 研究DNA的含量, 单双链等对复合体系光电响应的影响, 并综合TEM, UV-Vis, IR和荧光光谱等对其形貌和光谱性质进行表征. 结果表明, CdS纳米粒子(CdS NPs)与DNA链之间主要通过静电作用结合; DNA模板对CdS NPs的禁带宽度没有影响; 以DNA模板合成的CdS NPs具有较高的表面态密度, 其对CdS NPs的荧光有增强作用, 而对光电流响应有抑制作用, 并且DNA在复合体系中的含量影响荧光增强和光电流减弱的程度. 该复合体系在荧光标记检测和DNA的定量分析方面可能具有应用前景.     

Biochemical Characterization of Translesion Synthesis by Sulfolobus acidocaldarius DNA Polymerases

To study the DNA synthesis mechanism of Sulfolobus acidocaldarius, a thermophilic species from Crenarchaeota, two DNA polymerases of B family(polB1 and polB3), and one DNA polymerase of Y family(polIV) were recombinantly expressed, purified and biochemically characterized. Both DNA polymerases polB1(Saci_1537) and polB3(Saci_0074) possessed DNA polymerase and 3' to 5' exonuclease activities; however, both the activities of B3 were very inefficient in vitro. The polIV(Saci_0554) was a polymerase, not an exonuclease. The activities of all the three DNA polymerases were dependent on divalent metal ions Mn²⁺ and Mg²⁺. They showed the highest activity at pH values ranging from 8.0 to 9.5. Their activities were inhibited by KCl with high concentration. The optimal reaction temperatures for the three DNA polymerases were between 60 and 70℃. Deaminated bases dU and dI on DNA template strongly hindered primer extension by the two DNA polymerases of B family, not by the DNA polymerase of Y family. DNA polymerase of Y Family bypassed the two AP site analogues dSpacer and propane on template more easily than DNA polymerases of B family. Our results suggest that the three DNA polymerases coordinate to fulfill various DNA synthesis in Sulfolobus acidocaldarius cell.     

序列特异性DNA断裂蛋白质

序列特异性DNA断裂蛋白质是在序列特异性DNA结合蛋白质及小分子DNA断裂试剂基础上设计合成的。其基本原理是在含有DN A结合域的蛋白质上引入一个金属鳌合剂并鳌合一个适当的金属离子,其中序列特异性DNA结合蛋白质具有与DNA特定序列结合的能力,从而可以起导向物的作用,而引入的金属鳌合齐J与金属离子复合物具有断裂DNA的功能,两者协同作用可以达到序列特异性断裂DNA的目的。     

Fluorescence enhancement method for the determination of nucleic acids using cationic cyanine as a fluorescence probe

A fluorescence enhancement method with a cationic cyanine as a probe was developed for the determination of nucleic acids. Under the experimental conditions, the fluorescence enhancement of cyanine (lambda(ex)/lambda(em)= 524/591.5 nm) was observed in the presence of DNA. The calibration graphs were linear over the range of 0.01-15 microg mL(-1) for both calf thymus DNA (CT DNA) and fish sperm DNA (FS DNA). The limits of detection were 0.005 and 0.007 microg mL(-1) for CT DNA and FS DNA, respectively. The method was applied to the determination of DNA in synthetic and real samples and satisfactory results were obtained. A possible fluorescence enhancement mechanism was also studied.     

Label‐Free and Label Based Electrochemical Detection of Hybridization by Using Methylene Blue and Peptide Nucleic Acid Probes at Chitosan Modified Carbon Paste Electrodes

A chitosan modified carbon paste electrode (ChiCPE) based DNA biosensor for the recognition of calf thymus double stranded DNA (dsDNA), single stranded DNA (ssDNA) and hybridization detection between complementary DNA oligonucleotides is presented. DNA and oligonucleotides were electrostatically attached by using chitosan onto CPE. The amino groups of chitosan formed a strong complex with the phosphate backbone of DNA. The immobilized probe could selectively hybridize with the target DNA to form hybrid on the CPE surface. The detection of hybridization was observed by using the label‐free and label based protocols. The oxidation signals of guanine and adenine greatly decreased when a hybrid was formed on the ChiCPE surface. The changes in the peak currents of methylene blue (MB), an electroactive label, were observed upon hybridization of probe with target. The signals of MB were investigated at dsDNA modified ChiCPE and ssDNA modified ChiCPE and the increased peak currents were observed, in respect to the order of electrodes. The hybridization of peptide nucleic acid (PNA) probes with the DNA target sequences at ChiCPE was also investigated. Performance characteristics of the sensor were described, along with future prospects.     

DNA binding studies of Vinca alkaloids: experimental and computational evidence

Fluorescence studies on the indole alkaloids vinblastine sulfate, vincristine sulfate, vincamine and catharanthine have demonstrated the DNA binding ability of these molecules. The binding mode of these molecules in the minor groove of DNA is non-specific. A new parameter of the purine-pyrimidine base sequence specificty was observed in order to define the non-specific DNA binding of ligands. Catharanthine had shown 'same' pattern of 'Pu-Py' specificity while evaluating its DNA binding profile. The proton resonances of a DNA decamer duplex were assigned. The models of the drug:DNA complexes were analyzed for DNA binding features. The effect of temperature on the DNA binding was also evaluated.     

Construction and control of plasmid DNA network

The influences of different cations on plasmid DNA network structures on a mica substrate were investigated by atomic force microscopy (AFM). Interactions between the DNA strands and mica substrate, and between the DNA strands themselves were more strongly influenced by the complex cations (Fe(phen)3(2+), Ni(phen)3(2+), and Co(phen)3(3+)) than by the simple cations (Mg2+, Mn2+, Ni2+, Ca2+, Co3+). The mesh height of the plasmid DNA network was higher when the complex cations were added to DNA samples. The mesh size decreased with increasing DNA concentration and increased with decreasing DNA concentration in the same cation solution sample. Hence, plasmid DNA network height can be controlled by selecting different cations, and the mesh size can be controlled by adjusting plasmid DNA concentration.     

欧前胡素及同分异构体与DNA的作用机理及构效关系研究

在模拟人体生理条件下,采用紫外光谱法、荧光光谱法、DNA热变性及黏度法研究欧前胡素及同分异构体异欧前胡素与DNA的作用机制,并探讨其构效关系.紫外光谱表明,加入DNA后,欧前胡素和异欧前胡素的紫外光谱均呈现减色效应;荧光光谱显示,随着欧前胡素或异欧前胡素浓度的增大,DNA-BR的荧光被猝灭,表明欧前胡素和异欧前胡素对BR与DNA的结合存在竞争性抑制;盐效应、DNA热变性温度、黏度法等实验进一步证明欧前胡素和异欧前胡素与DNA的作用模式均为嵌插与静电混合作用模式.研究表明,欧前胡素和异欧前胡素均与DNA发生作用,且欧前胡素与DNA作用强于异欧前胡素.     

DNA-conjugated polymers for self-assembled DNA chip fabrication.

We developed two DNA-conjugated polymers, one based on polyallylamine and the other on polyacrylic acid, for use in DNA chips. A 30-mer single-stranded DNA probe and thioctic acid were covalently attached to polyallylamine as sidechains. The same single-stranded DNA and 3-(pyridyldithio)propionyl hydrazide were covalently attached to polyacrylic acid as sidechains. Both DNA-conjugated polymers could be specifically immobilized onto a gold sensor substrate by a self-assembly technique. The interactions between fully matched DNA and each DNA-conjugated polymer were investigated by surface plasmon resonance. A gold surface modified with either DNA-conjugated polymer recognized fully matched DNA much better than unmatched DNA. The hybridization selectivity and efficiency of DNA-conjugated polyallylamine was optimized by adjusting the pH so as to reduce the effects of cationic polymer sidechains. The hybridization selectivity and efficiency of DNA-conjugated polymers were higher than those of a conventional immobilized thiol-based DNA. The coating of DNA-conjugated polymers reduced nonspecific adsorption of DNA by the gold substrate. DNA-conjugated polyacrylic acid was more selective toward fully matched DNA than was DNA-conjugated polyallylamine. Therefore, DNA-conjugated polymers show promise for application in novel DNA chips.     

Detection of processed genetically modified food using CIM monolithic columns for DNA isolation

The availability of sufficient quantities of DNA of adequate quality is crucial in polymerase chain reaction (PCR)-based methods for genetically modified food detection. In this work, the suitability of anion-exchange CIM (Convective Interaction Media; BIA Separations, Ljubljana, Slovenia) monolithic columns for isolation of DNA from food was studied. Maize and its derivates corn meal and thermally pretreated corn meal were chosen as model food. Two commercially available CIM disk columns were tested: DEAE (diethylaminoethyl) and QA (quaternary amine). Preliminary separations were performed with standard solution of salmon DNA at different pH values and different NaCl concentrations in mobile phase. DEAE groups and pH 8 were chosen for further isolations of DNA from a complex matrix-food extract. The quality and quantity of isolated DNA were tested on agarose gel electrophoresis, with UV-scanning spectrophotometry, and by amplification with real-time PCR. DNA isolated in this way was of suitable quality for further PCR analyses. The described method is also applicable for DNA isolation from processed foods with decreased DNA content. Furthermore, it is more effective and less time-consuming in comparison with the existing proposed methods for isolation of DNA from plant-derived foods.