MALDI‐TOF‐Massenspektrometrie: Risikoanalyse im Flug

The high accuracy, molecular resolution and sensitivity of matrix‐assisted laser desorption/ionisation time‐of‐flight mass spectrometry (MALDI‐TOF‐MS) make it an efficient method for analysing all kinds of biomolecules including nucleic acids, proteins/peptides, carbohydrates and lipids. MALDI‐TOF‐MS based high‐throughput genotyping of genetic heterogeneities possesses the potential of becoming a routine method. MAL‐DI‐TOF‐MS can be used for the identification of proteins and posttranslational modifications. Taken together, MALDI‐TOF‐MS represents a integrated platform technology in bioanalytics and molecular medicine.     

双子表面活性剂研究进展和应用

双子表面活性剂是一类新型的表面活性剂,它是由联结基团通过化学键将两个或多个单体表面活性剂连接在一起,由此产生优异的表面活性等一系列的性质,从而获得了广泛的应用.本文就它的合成进展及在生物技术、抗病毒、环境保护、新材料制备等方面的应用作一介绍。     

DNA Microarrays

The complete human genes (ca. 100 000) as well as the whole spectrum of biological diversity should soon be able to be analyzed simultaneously by means of DNA microarrays using the fast technical advances that are occurring in this area. The particular strength of array analysis, typically based on the hybridization of nucleic acid probes attached to microchips with labeled RNA or DNA samples, results from the highly redundant measurement of many parallel hybridization events (see picture), which leads to an extraordinary level of assay validation.     

SVMs在微阵列表达数据分析中的应用

微阵列技术允许同时录制成百万的基因表达水平。但由于经费和工艺的限制,目前研究者获得的表达数据集往往包含少量的样本,而基因表达的测量值却有上万条。很多传统的统计方法无法分析这样的数据,本文结合数据挖掘中统计学习理论的相关知识,详细介绍了一种有监督分析方法———支持向量机(SVMs)在微阵列表达数据分析中的应用。     

Synthesis of a novel multivalent galactoside with high hepatocyte targeting for gene delivery

A novel bifunctional glycolipid which carded a cluster of thiogalactosides as the hepatocyte targeting ligand for gene delivery was prepared. Hexa-antennary alcohol 1 was used as the core scaffold to attach a cholesterol molecule by a poly（ethylene glycol） chain, while its remaining branches were linked with five acetylgalactosides, which would be deacetylated later to produce pentaantennary galactoside. Liposome containing the galactoside showed high affinity and transfection activity in hepatoma cells HepG2.     

Polyethylenimine (PEI)g-comb-poly(ethylene glycol)-transferrin(I): Tumor-targeted Vector for Gene Delivery In-vitro

A new vector, PEG as a core, low Mw PEI was grafted to PEG, and transferrin was conjugated the co-polymer to form PEI-g-PEG-transferrin1,2. NMR, FT-IR and TGA spectroscopy confirmed the structures of activated PEG and the final products. The MW of PEI-g-P…     

Impact of Cationic Charge Density and PEGylated Poly(Amino Acid) Tercopolymer Architecture on Their Use as Gene Delivery Vehicles. Part 2: DNA Protection,Stability, Cytotoxicity,and Transfection Efficiency

The impact of the molecular architecture on the transfection efficiency of PEGylated poly(amino acid) block copolymers was investigated for PEG‐b‐p(l ‐Lys)_x‐b‐p(l ‐Leu)_y, PEG‐b‐p(l ‐Leu)_x‐b‐p(l ‐Lys)_y, and PEG‐b‐p((l ‐Leu)_x‐co‐(l ‐Lys)_y). The block lengths of p(l ‐Lys) and p(l ‐Leu) were varied between 10, 20, and 40; and 10 and 20, respectively, to study the influence of the ionic/hydrophobic balance. The results show that ABC triblock copolymers form smaller and more stable polyplexes with plasmid DNA than AB diblock copolymers—as verified by long‐term aggregation and ethidium bromide exclusion studies—protect the DNA more effectively against nucleases, and provide better transfection efficiencies, as indicated by total protein as well as luciferase expression. More detailed studies revealed that triblock copolymers with p(l ‐Leu) forming the C‐block were most efficient in DNA complexation with a 2.3 times higher transfection rate. Furthermore, increasing the cationic character by increasing the p(l ‐Lys) chain length led to up to 25% higher transfection but at the same time induced some cytotoxicity. Diblock copolymers, where the amino acid–building blocks exist as a random copolymer, bind more loosely with DNA leading to less compact and less stable aggregates with lower transfection efficiencies.     

Chemical Physics in Living Cells-using Light to Visualize and Control Intracellular Signal Transduction?

Cells are crowded microenvironments filled with macromolecules undergoing constant physical and chemical interactions. The physicochemical makeup of the cells affects various cellular responses, determines cell-cell interactions and influences cell decisions. Chemical and physical properties differ between cells and within cells. Moreover, these properties are subject to dynamic changes in response to environmental signals, which often demand adjustments in the chemical or physical states of intracellular molecules. Indeed, cellular responses such as gene expression rely on the faithful relay of information from the outside to the inside of the cell, a process termed signal transduction. The signal often traverses a complex path across subcellular spaces with variable physical chemistry, sometimes even influencing it. Understanding the molecular states of such signaling molecules and their intracellular environments is vital to our understanding of the cell. Exploring such intricate spaces is possible today largely because of experimental and theoretical tools. Here, we focus on one tool that is commonly used in chemical physics studies-light. We summarize recent work which uses light to both visualize the cellular environment and also control intracellular processes along the axis of signal transduction. We highlight recent accomplishments in optical microscopy and optogenetics, an emerging experimental strategy which utilizes light to control the molecular processes in live cells. We believe that optogenetics lends unprecedented spatiotemporal precision to the manipulation of physicochemical properties in biological contexts. We hope to use this work to demonstrate new opportunities for chemical physicists who are interested in pursuing biological and biomedical questions.     

O-羧甲基壳聚糖的制备及应用研究进展

O_羧甲基壳聚糖是壳聚糖的一种衍生物 ,具有比壳聚糖更优良的特性 ,有着更广阔的应用前景。本文对它的制备、性质、应用 ,特别是其在药物释放及基因治疗方面应用的研究进展进行了综述。