MULTI-WALL CARBON NANOTUBE-BASED DNA NANOSENSOR FOR DETERMINING MITOXANTRONE-DNA INTERACTION IN-VITRO

The present study involves the development of a carbon nanotube based DNA nanosensor to determine the toxicological behavior of mitoxantrone (MTX). Mitoxantrone intercalates with DNA and produces a MTX-DNA adduct, resulting in the blockade of protein synthesis and excessive production of free radicals in the myocardium which eventually leads to cardiac toxicity. So, our work employs a DNA nanosensor to investigate the interaction of MTX with DNA. Multi-wall carbon nanotubes (MWCNTs) were functionalized with carboxyl group and were used for immobilization of DNA to construct the DNA nanosensor. The DNA nanosensor was immersed in MTX solution to monitor MTX-DNA interaction with respect to time and alter the resistance of the nanosensor. It was observed that MTX-DNA interaction is fast initially and as time elapses, the change in interaction gets slow due to formation of MTX-DNA adduct. The limit of detection (LOD) and limit of quantification (LOQ) were found as 150 (ng/mL) and 456 (ng/mL), respectively, for DNA nanosensor. This study suggests that the potentiometric nanosensor allows real-time monitoring of the drug-DNA interaction changes by measuring the potential at DNA/sensor interface which can prove to be an important tool in drug discovery pipelines and molecular toxicology.     

Matrix splicing system

The string splicing system was introduced by Tom Head, which stands as an abstract model for the DNA recombination under the influence of restriction enzymes and ligase enzymes. However, it is observed that strings are not very capable of modelling the complex chemical process. Hence, in this article, matrix splicing system is introduced with a new splicing operation among the matrices. It is shown with an illustration that the DNA recombination process can be simulated by the matrix splicing system, which justifies the suitability of the matrices for modelling the complex processes of the molecules. The properties of the components of the system such as cutting rules and the splicing rules are discussed. Besides some properties of the system, it is shown that this system stands as a theoretical model for splicing strings in parallel. The abstraction of the ligase enzymes is explained which is missing in all the splicing models that have come out so far. The ability of the system in generating new patterns is also outlined.     

新型基因枪微弹材料可行性初步研究-Ⅰ

基因枪在未来临床基因转导中很有前途,但目前所用微弹材料金、钨都属于重金属,其长期存在于人体的安全性尚无法估计。提出用羟基磷灰石(HAP)微粒来代替金或钨微粒,从理论上推导了这种取代的可行性,并报告了一种HAP微粒的制备及其负载DNA的研究结果。理论推导完全按照物理学方法进行。实验部分的方法:将稳定剂H以一定速度和比例滴入一定浓度的Ca(H2PO4)2溶液中,再按照一定的速度和比例滴入Ca(OH)2饱和溶液,期间或完成后超声处理一定时间,将所得HAP微粒溶液与亚精胺和DNA以一定比例和浓度在一定pH条件下混合。结论:所得HAP粒径值符合要求,并且能够高效负载DNA。     

结核分枝杆菌融合抗原Ag85B-ESAT6真核表达载体的构建及鉴定

以结核分枝杆菌H37Rv株的基因组作为模板,将Ag85B和ESAT6编码基因进行PCR扩增,然后采用基因剪接重叠扩增PCR法(gene SOEing)将其通过疏水甘氨酸接头(GGIGIAPG)连接融合,定向克隆至质粒Pvax1中,构建结核分枝杆菌Ag85B-ESAT6融合抗原的真核表达质粒Pvax1/AE.经单双限制性内切酶图谱、PCR产物及DNA测序分析等多种方法鉴定,证实Pvax1/AE真核表达质粒构建成功.为进一步研究其结核核酸疫苗原型的免疫保护效果奠定了基础.     

压电基因传感器检测芽孢杆菌靶序列研究

在石英晶体微天平(QCM)上用生物素亲和素法和自组装法2种不同的方法固定寡核苷酸探针,构建压电基因传感器,对芽孢杆菌靶序列进行实时检测。结果表明:生物素亲和素法固定探针效果更好,靶序列浓度为0.05~0.5μmol/L时,有很好的线性关系,线性回归方程为Y=93.88X+10.88(R=0.989 0,N=6,P<0.001),非线性误差为±4.7%。该传感器特异性较好,能够识别错配3个碱基的序列。     

DNA计算的原理及研究进展

阐述了DNA计算的机理及其数学原理,介绍了Adleman实验,指出了DNA计算目前的应用领域和存在的问题,并对DNA计算的发展前景进行了展望。     

Cover Picture: Protein Detecting Arrays Based on Cationic Polythiophene–DNA‐Aptamer Complexes (Adv. Mater. 20/2006)

The cover image depicts biochips based on responsive nanoaggregates made from stoichiometric complexes between a cationic polythiophene and an appropriate DNA aptamer. These structures undergo a conformational transition from an unfolded to a folded (G‐quadruplex) structure in the presence of a specific target protein that results in a significant increase of the fluorescence intensity, as reported on p. 2703 by Leclerc and co‐workers.     

Sensitive determination of DNA based on resonance light scattering enhancement of azocarmine G and CTAB

A new method for the determination of DNA was developed with azocarmine G（AG） in the presence of cetyltrimethylammonium bromide（CTAB） by the resonance light scattering （RLS） technique. The synthetic samples were determined with satisfactory results, and the reaction mechanism was also studied. The results show that under the optimum conditions, the weak RLS signal of AG can be enhanced by DNA, which results from the formation of a new ternary complex AG-CTAB-DNA with large size. Moreover, the enhanced RLS intensity at 552 nm is directly proportional to the concentration of DNA in the range of 0 - 1.0 μg/mL for fish sperm DNA （fsDNA） and 0 - 1.5μg/mL for calf thymus DNA （ctDNA）. Based on this, a new assay of DNA can be established. The detection limits （3σ） are 2. 1 ng/mL for fsDNA and 2.2 ng/mL for ctDNA, respectively.     

Spectroscopy Study on Crystal Structure of Ce（NO3）3 （phen）2 and Interactions of Ce（NO3）3 （phen）2 with DNA

Inrecentyears ,Komiyaetal.[1] havefoundthatrareearthsionsmaybeoneofthestrongestcutre agentsofnucleicacids .Theexperimentalresults ,thatrareearthsrepresscancersonwholeanimalbodiesandonhumanbodies(invitro) ,indicatedthatrareearthselementsactuallyhavestrongf…