Expression and Purification of ZNF191（243-368） in Three Expression Systems

ZNF191 （243-368）, a new human zinc finger protein, probably relates to some hereditary diseases and cancers, To obtain adequate amount of ZNF191（243-368） for the study of its property, structure and function, three different expression systems of inclusion-body, glutathione S-transferase （GST）, and hexahistidine （6 × His） were used and compared. Among these systems, the expression level of ZNFI91（243-368） was increased in inclusion body system under a higher isopropylthio-β-D-galactoside （IPTG） concentration, but the non-target proteins were also increased more, which made its purification more difficult and the yield lower. The expression of His-tag fusion protein was almost not affected by IPTG concentration, temperature and inducing time. At a high IPTG concentration the highest expression yield for GST fusion protein was obtained. And the fusion proteins can be partially purified by a single affinity chromatography step. The fusion protein systems show advantages for expression of these proteins.     

Production of recombinant bleaching enzymes from thermophilic microorganisms in fungal hosts

Cost-effective production of enzymes for industrial processes makes the appropriate selection of the host-vector expression system critical. We have developed two systems for the bulk production of bleaching enzymes from thermophiles. Kluyveromyces lactis has been developed as a secretion host employing expression vectors based on the 2μ-like plasmid pKD1 of Kluyveromyces drosophilarium. Our second system involves the filamentous fungus Trichoderma reesei. Fusion and nonfusion vectors have been constructed using the strong cellobiohydrolase 1 (cbh1) promoter. The KEX2 protease cleavage site and a 6 × HIS-tag have been incorporated to facilitate both cleavage and purification of the mature foreign proteins.     

A combination of modified particle swarm optimization algorithm and support vector machine for gene selection and tumor classification

In the analysis of gene expression profiles, the number of tissue samples with genes expression levels available is usually small compared with the number of genes. This can lead either to possible overfitting or even to a complete failure in analysis of microarray data. The selection of genes that are really indicative of the tissue classification concerned is becoming one of the key steps in microarray studies. In the present paper, we have combined the modified discrete particle swarm optimization (PSO) and support vector machines (SVM) for tumor classification. The modified discrete PSO is applied to select genes, while SVM is used as the classifier or the evaluator. The proposed approach is used to the microarray data of 22 normal and 40 colon tumor tissues and showed good prediction performance. It has been demonstrated that the modified PSO is a useful tool for gene selection and mining high dimension data.     

基于Gene Ontology的表达谱与基因功能相似性的相关性研究

聚类是芯片数据分析中被广泛使用的方法。未知基因的功能通常通过其与已知基因在不同生物状态下具有表达相似性来进行预测。然而，还未有人就这种通过表达相似性来进行功能注释的方法的可靠性进行评估。本文利用Gene Ontology对表达相似性和基因功能相似性的相关关系进行了全面的研究。研究表明，尽管表达谱的相似性和基因功能相似性之间有一定的依赖关系，但相关性较弱。在Gene Ontology的三大类中，相对生物过程和分子功能，基因表达谱的相似性更有助于细胞组分的注释。本文的研究结果对于基因功能的预测有一定的指导意义。     

Fluorescence-based nucleic acid detection and microarrays

Recent analytical innovations for nucleic acid detection have revolutionized the biological sciences. Single nucleic acid sequence detection methods have been expanded to incorporate multiplexed detection strategies. A variety of nucleic acid detection formats are now available that can address high throughput genomic interrogation. Many of these parallel detection platforms or arrays, employ fluorescence as the signaling method. Fluorescence-based assays offer many advantages, including increased sensitivity, safety and multiplexing capabilities, as well as the ability to measure multiple fluorescence properties. Multiplexed microarray platforms provide parallel detection capabilities capable of measuring thousands of simultaneous responses. This review will discuss both single target detection and microarray applications with a focus on gene expression and pathogenic microorganism (PM) detection.     

线型碳链LiC_(2n)Li的结构和电子光谱的密度泛函理论研究

应用密度泛函理论,在B3LYP/6 31G(d)水平上优化得到了线型簇合物LiC2nLi(n=1 ~10,D∞h)的基态平衡几何构型,并计算了它们的谐振动频率.利用含时密度泛函理论,计算了簇合物LiC2nLi的X1∑ +g→11∑ +u跃迁的垂直激发能,以及相应的振子强度.基于计算结果,建立了跃迁能和体系大小n的解析关系式. 同时也计算了体系的第一绝热电离能,讨论了体系的电离能与体系大小n的关系.     

Bioanalytical methods applied to endocrine disrupting polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans. A review

The usual methods for determining polychlorinated dibenzo-p-dioxins (PCDD), polychlorinated dibenzofurans (PCDF) and polychlorinated biphenyls (PCB) are generally expensive and time consuming. This fact has favored the development of faster and cheaper techniques, based on immunoassays and bioassays. This paper reviews these bioanalytical methods and their analytical importance at the present moment.     

基于PiggyBac转座系统的低溢漏诱导型Tet-On过表达体系的建立及应用

为避免诱导基因稳定表达的Tet-On诱导表达系统溢漏表达,实现简便且高效的外源基因稳定诱导表达, 本研究拟在Tet-On调控的转录水平基础上,将基于稳定配体Shield-1的不稳定结构域FK506结合蛋白引入目的基因的N端,从蛋白水平控制其本底表达水平.为验证该系统的效果,本研究以荧光蛋白TdTomato为报告基因,经流式分析结果证明优化后的体系较原体系的溢漏表达在蛋白水平上降低7倍左右.将该系统应用于基于小鼠胚胎干细胞的体外牙向分化模型,在诱导因子Dox和稳定配体Shield-1的协同作用下,诱导表达牙齿发育相关转录因子Hand2提高了牙向分化诱导的完成度.