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41.
以紫外光谱、荧光光谱、粘度法和凝胶电泳方法研究了全反式维甲酸合钇(Ⅲ)配合物与DNA的作用。结果表明,该配合物能在生理条件下比配体和金属离子更有效地切割质粒DNA,体系离子强度和pH值的变化对配合物的切割活性有较大影响,自由基捕捉剂的加入不影响配合物的切割活性。该配合物对DNA的切割可能通过水解机理进行。该配合物可使DNA的粘度增加,使EB-DNA体系的荧光强度和DNA溶液的紫外吸收强度降低。据此推断,该配合物主要以嵌入方式与DNA作用。 相似文献
42.
In weakly acidic buffer medium, the interaction of amikacin with calf thymus DNA, yeast RNA and denatured DNA has been investigated by using resonance Rayleigh scattering (RRS) technique. The result shows that calf thymus DNA is capable of enhancing the RRS intensity of the amikacin, while yeast RNA and denatured DNA have very little enhancement effect. Based on the characteristics, a sensitive assay for detecting double-stranded DNA in the presence of denatured DNA and yeast RNA has been developed. The enhancement of the RRS signal is directly proportional to the concentration of double-stranded DNA in the range 0.02-12.0 μg ml−1 for calf thymus DNA and its detection limit (3σ) is 2.5 ng ml−1. The method shows a wide linear range and high sensitivity, and almost no interference can be observed from RNA, denatured DNA, amino acid and most of the metal ions. The trace amounts of nucleic acid in synthetic samples and practical samples are determined with satisfactory results. Therefore, the proposed method is promising for as an effect means for recognition in vivo and determination in situ of double-stranded DNA. 相似文献
43.
抗癌药物的电化学研究(Ⅱ)道诺霉素在DNA修饰石墨粉末微电极上的电化学行为及分析应用 总被引:8,自引:0,他引:8
研究了道诺霉素 ( DNM)在石墨粉末微电极和 DNA修饰石墨粉末微电极上的电化学行为 ,并分析了产生差别的原因。在此基础上 ,提出了测定微量 DNM的方法 ,DNM浓度在 1 .0× 1 0 - 7~ 1 .0× 1 0 - 5mol/L之间其微分脉冲伏安 ( DPV)峰电流与浓度有良好的线性关系 ,检出限为 5 .0× 1 0 - 8mol/L。采用标准加入法测定了模拟样品中的 DNM,回收率在 94%~ 1 0 8%之间 ,结果令人满意 相似文献
44.
Optical sensors based on hybrid DNA/conjugated polymer complexes 总被引:2,自引:0,他引:2
Ho HA Béra-Abérem M Leclerc M 《Chemistry (Weinheim an der Bergstrasse, Germany)》2005,11(6):1718-1724
Single-stranded DNA (ss-DNA) can specifically bind to various targets, including a complementary ss-DNA, ions, proteins, drugs, and so forth. When binding takes place, the oligonucleotide probe often undergoes a conformational transition. This conformational change of the negatively charged ss-DNA can be detected by using a water-soluble, cationic polythiophene derivative, which transduces the complex formation into an optical (colorimetric or fluorometric) signal without any labeling of the probe or the target. This simple and rapid methodology has enabled the specific and sensitive detection of nucleic acids and human thrombin. This new biophotonic tool can easily be applied to the detection of various other biomolecules and is also useful in the high-throughput screening of new drugs. 相似文献
45.
Molecular dynamics simulations of double-helical DNA oligomers have been performed to investigate differences in the structure, dynamics, and hydration of F-F and T-T mispairs. Hexamers containing F-F pairs were found to be more dynamic, especially in the region of the mispair itself. This dynamic variability derives from greater flexibility of F-F pairs. The T-T mispairs, on the other hand, were found to be comparatively tightly bound as wobble pairs. The major and minor groove edges of the T-T pairs were observed to be solvated at exposed carbonyl positions by at least one water molecule, while F-F pairs lacked solvating waters. Stacking interactions were nearly identical for T-T and F-F pairs, leading to similar average structures, even though F stacking was more dynamically variable. Solvation differences between F-F and T-T therefore support the steric exclusion model for nucleotide incorporation in DNA replication. Large differences in the orientation of minor groove functional groups, in addition to differences in solvation, further rationalize why F bases present during DNA extension events induce stalls. Two novel nucleotides are proposed to further elucidate minor groove interactions of DNA with polymerase molecules.Electronic Supplementary Material This Material consists of equilibration protocol, plots of center-of-mass stacking, water radial distribution functions, helical parameter dynamics, and dynamics data for a control AT sequence. Supplementary material is available in the online version of this article at Contribution to the Jacopo Tomasi Honorary Issue 相似文献
46.
Fabrice Freville Tristan Richard Katell Bathany Serge Moreau 《Helvetica chimica acta》2006,89(12):2958-2974
A new strategy to cyclize short synthetic oligonucleotides on DNA or RNA target strands is described. The approach is based on metal‐templated cyclization of short synthetic oligonucleotides conjugated with two chelating 2,2′ : 6′,2′′‐terpyridine (Tpy) moieties at their 3′‐ and 5′‐ends. Cyclization after metal addition (Zn2+, Fe2+) was demonstrated by means of thermal‐denaturation experiments, MALDI‐Q‐TOF‐MS, and gel electrophoresis (PAGE). 1D‐ and 2D‐NMR Experiments were performed to analyze the association of complementary strands after metal‐mediated cyclization. Our protocol allows the efficient circularization of synthetic oligonucleotides. Thereby, the hybridization on a complementary strand was more efficient with an RNA target strand and a 2′‐O‐methylated circularized oligomer. 相似文献
47.
5-氟尿嘧啶-1-乙酸合铜(Ⅱ)的合成及其与DNA的作用 总被引:1,自引:0,他引:1
The 5-fluorouracil-1-acetic acid (5FuAA) and its Cu(Ⅱ) complex (5FuAACu) were synthesized and the date for the crystal complex was obtained. The interaction of 5-fluorouracil-1-acetic acid (5FuAA) and its Cu(Ⅱ) complex (5FuAACu) with DNA was also investigated by using spectral, viscometric, electrochemical and agarose gel electrophoresis methods. The results of interaction with DNA suggest that both 5FuAA and 5FuAACu can bind to DNA in a static electricity attraction mode. But the attraction of 5FuAACu is greater than that of 5FuAA. 相似文献
48.
Study of various binding materials like potassium bromide, poly(vinyl alcohol), starch, silver and aluminum has been carried out using laser-induced breakdown spectroscopy (LIBS). The role of matrix effects using these five binders on LIBS signal intensity was investigated for better performance of LIBS technique as a quantitative analytical tool. For comparative study of different binders, the signal intensity of different Mg lines at 518.3, 517.2, 383.8 and 279.5 nm wavelengths were recorded for pellets prepared with known concentrations of Mg in these binders. The influence of laser energy on ablated mass under different binding materials and its correlation with LIBS signal intensity has been explored. Optical scanning microscopy images of the ablated crater were studied to understand the laser ablation process. The study revealed that the binding material plays an important role in the generation of LIBS signal. The relative signal intensity measured for a standard Mg line (at 518.3 nm) were 735, 538, 387, 227 and 130 for potassium bromide, starch, poly(vinyl alcohol), silver and aluminum as binders, respectively. This indicates clearly that potassium bromide is better as a binder for LIBS studies of powder samples. 相似文献
49.
Two kinds of thio-heterocyclic fused naphthalene carboxamides, 3a-b, 4a-b, were designed, synthesized and quantitatively evaluated as efficient antitumor and DNA photocleaving agents. Compound 3a or 3b, having the thiophene ring, intercalated into DNA more strongly than compound 4a or 4b, having the thioxanthene ring. Compound 4a or 4b, photocleaved DNA more efficiently than 3a or 3b via superoxide anion. Compound 4a was the strongest inhibitor for P388 (murine leukemia cell), while 3a was the most cytotoxic one against A549 (human lung cancer cell). Each new compound showed stronger DNA photocleaving activity than corresponding naphthalimide. 相似文献
50.