仪器分析测试技术信息化教学探索与实践

针对高职学生的特点，以仪器分析测试技术课程实训教学为例，按照课前布置学习任务，学生翻转课堂学习，"教、学、做"一体化课堂教学，课后复习巩固的形式，开展信息化教学的探索与实践，并对信息化教学的效果和存在的问题进行了分析。通过信息化教学改革，仪器分析测试技术课程突破了传统教学时空的限制，激发了学生学习的兴趣，构建了"学生主体、教师主导"的教学新模式，提高了课堂教学效果，对推动高职课堂信息化教学的改革具有一定的借鉴意义。     

二维DNA晶体的程序化设计与自组装的研究进展

按照Watson-Crick的碱基配对原则，在理论上能够人工设计与合成DNA碱基序列并自组装成任何一维和二维结构的DNA晶体。DNA分子这种底端向上(bottom-up)的自组装模式为我们提供了一种精确合成纳米材料的方法。本文将从程序化设计、合成刚性的DNA分子瓦(DNA tile)、分子瓦自组装成二维DNA晶体以及二维DNA晶体作为模板在纳米技术中的应用等方面展开，简述这一新奇的并且有着潜在应用前景的研究领域的最新进展。     

基于微机械加工技术的双腔型生物传感器

利用微机械加工技术研制了具有三维结构的腔型传感器，双腔型工作电极与Ag/Agcl参比电极集成在同一微芯片上。考察了微腔型电极的电化学特性及其对H2O2含量的测定。并以此为基础电极制备了半乳糖、葡萄糖双腔型生物传感器。结果表明，该传感器可同时测定半乳糖、葡萄糖双组分，线性上限分别为4．5mmol/L和4．0mmol/L。而且在测试双组分过程中，没有观察到明显的交叉干扰现象。     

Electrophoretic properties of complexes between DNA and the cationic surfactant cetyltrimethylammonium bromide

We use agarose gel electrophoresis to characterize how the monovalent catioinic surfactant cetyltrimethylammonium bromide (CTAB) compacts double-stranded DNA, which is detected as a reduction in electrophoretic DNA velocity. The velocity reaches a plateau at a ratio R = 1.8 of CTAB to DNA-phosphate charges, i.e., above the neutralization point, and the complexes retain a net negative charge at least up to R = 200. Condensation experiments on a mixture of two DNA sizes show that the complexes formed contain only one condensed DNA molecule each. These CTAB-DNA globules were further characterized by time-resolved measurements of their velocity inside the gel, which showed that CTAB does not dissociate during the migration but possibly upon entry into the gel. Using the Ogston-model for electrophoresis of spherical particles, the measured in-gel velocity of the globule is quantitatively consistent with CTAB having two opposite effects, reduction of both the electrophoretic charge and DNA coil size. In the case of CTAB the two effects nearly cancel, which can explain why opposite velocity shifts (globule faster than uncomplexed DNA) have been observed with some catioinic condensation agents. Dissociation of the complexes by addition of anionic surfactants was also studied. The DNA release from the globule was complete at a mixing ratio between anionic and cationic surfactants equal to 1, in agreement with equilibrium studies. Circular DNA retained its supercoiling, and this demonstrates a lack of DNA nicking in the compaction-release cycle which is important in DNA transfection and purification applications.     

Multiplex amplified product-length polymorphism analysis of 36 mitochondrial single-nucleotide polymorphisms for haplogrouping of East Asian populations

We present a reliable, rapid, and economical multiplex amplified product-length polymorphism (APLP) method for analyzing the haplogroup-diagnostic mitochondrial single-nucleotide polymorphisms (mtSNPs) in East Asian populations. By examining only 36 haplogroup-specific mtSNPs in the coding region by using four 9-multiplex polymerase chain reaction (PCR) and subsequent electrophoresis, we could safely assign 1815 individuals from 8 populations of Japanese, Korean, Chinese, and Germans to 45 relevant haplogroups. This multiplex APLP analysis of coding-region mtSNPs for haplogrouping is especially useful not only for molecular phylogenetic studies but also for large-scale association studies due to its rapid and economical nature. This is the first panel of mtSNPs in the coding region to be used for haplogrouping of East Asian populations.     

Detecting DNA Damage with a Silver Solid Amalgam Electrode

Mercury electrodes modified with supercoiled (sc) DNA have been used as highly sensitive tools for the detection of DNA strand breaks or as sensors for DNA cleaving substances. In this paper we show that silver solid amalgam electrode (AgSAE), in connection with alternating current voltammetry, provides similar information about DNA damage as the hanging mercury drop electrode. The AgSAE can be used for the detection of enzymatic or chemical DNA cleavage in solution or at the electrode surface. AgSAE modified with scDNA can be utilized as a sensor for DNA nicking substances.     

Monte Carlo Simulation of the Assembly of bis‐Biotinylated DNA and Streptavidin

We present Monte Carlo simulations of the self‐assembly of bivalent bis‐biotinylated DNA molecules with the tetravalent biotin‐binding protein streptavidin (STV). By fitting the STV binding probabilities for the four possible valencies, the modelling correctly reproduces the dependencies of various network parameters experimentally observed in an earlier study. The combined results from the experimental and theoretical studies suggest that the binding probability for divalent STV formation is about 50 times larger than for the formation of trivalent and about 200 times larger than for tetravalent STV. In accordance with the experimental results, the modelling also indicates that the mixture of an equimolar ratio of DNA and STV leads to a maximum in size of the oligomeric DNA–STV clusters formed. Furthermore, we found a percolation transition in which the DNA cluster size increases rapidly with increasing DNA concentration resulting in the formation of a single supercluster at elevated concentrations. This behaviour coincides with the occurrence of an immobile band previously observed in electrophoretic experiments, indicating the formation of extremely large DNA–STV aggregate networks.     

Molecular modeling of intercalation complexes of antitumor active 9-aminoacridine and a [d,e]-anellated isoquinoline derivative with base paired deoxytetranucleotides

Summary Intercalators are molecules capable of sliding between DNA base pairs without breaking up the hydrogen bonds between the DNA bases. On the basis of molecular mechanics calculations structural, models of B-DNA tetranucleotide intercalation complexes of some cytostatic active 9-aminoacridines and of a [d, e]-anellated isoquinoline derivative are presented. The drug complexes are stabilized by energetically favouredvan der Waals interactions and by selective hydrogen bonds between the side chains of the drugs and the DNA bases. Semiempirical quantum chemistry calculations revealed that the chromophoric system of the intercalators is able to form ,-charge-transfer interactions with the purine bases of the base paired deoxytetranucleotides. The theoretical findings are of interest for a more specific drug design of cytostatically active agents.

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Molecular Modeling von Interkalationskomplexen antitumoraktiver 9-Aminoacridine sowie eines [d, e]-anellierten Isochinolinderivates mit basengepaarten Desoxytetranukleotiden

Zusammenfassung Interkalatoren sind Moleküle, die in der Lage sind, sich zwischen DNA-Basenpaare einzulagern, ohne die Wasserstoffbrücken zwischen den DNA-Basen aufzubrechen. Auf der Basis von molekülmechanischen Rechnungen werden Tetranukleotid-Interkalationskomplexe von verschiedenen zytostatisch aktiven 9-Aminoacridinen und von einem [d, e]-anellierten Isochinolinderivat präsentiert. Die Komplexe werden durch energetisch günstigevan der Waals-Interaktionen sowie durch selektive Wasserstoffbrückenbindungen zwischen den Seitenketten der Wirkstoffe und den DNA-Basen stabilisiert. Semiempirische quantenchemische Rechnungen ergaben, daß der Chromophor der Interkalatoren in der Lage ist, ,-charge-transfer Wechselwirkungen mit den Purinbasen der basengepaarten Desoxytetranukleotide auszubilden. Die theoretischen Ergebnisse sind für ein spezifischeres Wirkstoffdesign zytostatisch aktiver Verbindungen von Interesse.