反义寡核苷酸药物癌泰得的定性分析方法研究

 癌泰得 (ACTCACTCAGGCCTCAGACT)为端粒酶表达抑制活性反义寡核苷酸 .为了探讨其定性检测手段 ,通过阴离子交换高效液相色谱和毛细管凝胶电泳分析方法 ,确定了该硫代寡核苷酸以及与其有关的短序列和部分未被硫代类似物的保留时间 ,并分析了不同混合物样品 .结果表明 ,阴离子交换高效液相色谱对硫代寡核苷酸骨架上的差异非常敏感 ,可很好地分离长度相同的硫代和未完全硫代类似物 ,并且随未被硫代磷酸基数目增加 ,保留时间依次缩短 .阴离子交换高效液相色谱对硫代寡核苷酸的长度不敏感 ,不能分离相差一个碱基的硫代寡核苷酸 .毛细管凝胶电泳可很好地分离长度相差一个碱基的硫代寡核苷酸 ,不能分离同长硫代和部分硫代寡核苷酸 .高效液相色谱结合毛细管凝胶电泳可有效地确定癌泰得的纯度和修饰程度 .     

气相色谱质谱联用在食品检验中的应用

介绍了气相色谱质谱联用技术的原理、特点及相关性能,重点阐述了气相色谱质谱联用技术在食品检验领域的应用,并且为气相色谱质谱联用技术在食品检测分析方面的应用提出改进意见,以保证其在食品检验领域发挥更重要的作用。     

寡核苷酸的优化设计

在核酸分子杂交、ＤＮＡ序列测定和通过ＰＣＲ放大ＤＮＡ片段等实验中 ,都需要使用寡核苷酸作为探针或引物 ,而对这些反应的质量起最重要影响作用的 ,就是这些寡核苷酸探针或引物。用优化的寡核苷酸进行实验能够很快得到好的结果 ,而用不够合适的寡核苷酸时 ,常常得出似是而非的结果 ,不仅大大增加了后续实验的工作量 ,还可能一无所获。怎样优化设计寡核苷酸呢 ?至少有下列收稿日期 :2 0 0 1 0 4 0 9几个方面的问题需要考虑。1 .估测可能形成的ＤＮＡ或ＲＮＡ双链的稳定性寡核苷酸 ,无论是ＤＮＡ的或者ＲＮＡ的 ,都有形成双链结构的潜在可能…     

UPLC/Q-TOF-MS联用技术在药物分析中的应用进展

超高效液相色谱与四级杆飞行时间质谱(UPLC/Q-TOF-MS)联用,将超高效液相色谱的高效分离能力和高灵敏度的特性与四级杆飞行时间质谱的高分辨特性有机结合起来,在药物分析领域得到越来越广泛的应用。本文对近年来UPLC/Q-TOF-MS在天然药物成分分析、药效成分代谢动力学研究、中药指纹图谱建立、目标成分快速发现和表征等领域中的应用进行了概述,并指出其在药物分析领域中的优势和未来的发展方向。     

高效薄层色谱法纯化合成寡核苷酸及其衍生物

在分子生物学研究的许多领域均需要一定纯度的寡核苷酸.目前寡核苷酸的纯化方法主要有高效液相色谱法及电泳法两种.这两种方法不仅需要一定的仪器设备而且纯化周期长(2—3d)、回收率低(50%—80%).文中报道建立了一种高效薄层色谱纯化寡核苷酸及其衍生物的方法.该方法可在3—4h 内获得寡核苷酸纯品,平 均回收率可达97.7%.     

SELEX技术及Aptamer研究的新进展

综述了近几年指数富集的配体系统进化(SELEX)技术的改良与寡核苷酸配基(aptamer)研究应用方面的新进展.Aptamer是指利用SELEX(systematicevolutionofligandsbyexponentialenrichment)技术,从随机寡核苷酸文库中筛选获得的能够与靶分子特异结合的短单链寡核苷酸配基,通常具有纳摩尔到皮摩尔的亲和力.高通量筛选的技术特点与aptamer精确识别、易体外合成与修饰等特性,使得aptamer在分析化学与生物医药研究方面具有广阔的应用前景.     

反义寡核苷酸的化学修饰

反义寡核苷酸的功能在很大程度上取决于其稳定性、生物利用度及与靶基因结合或反应的特性．通过特定的化学修饰可以改变这些物理、化学特性,从而增加其抗病毒、抗肿瘤及对其他特定基因的表达抑制活性．     

质谱技术在植物内源激素检测中的应用(综述)

植物内源激素对植物的各种生理活动具有显著的调节作用,但含量极少,对其进行超微量定量检测具有重要意义。在各种检测方法中,质谱法因具有高效、快速、灵敏的优点而得以广泛应用。本文综述近年来质谱技术在植物内源激素检测中的应用,包括样品前处理方法、有机质谱联用技术(气相色谱-质谱、液相色谱-质谱)和生物质谱等,并探讨其未来研究方向。     

蛋白质结构与相互作用研究新方法——交联质谱技术

蛋白质的空间结构信息以及蛋白质间的相互作用信息对于研究蛋白质的功能有重要意义.研究蛋白质结构与相互作用的传统技术,如核磁共振技术、X射线晶体衍射技术等,对于蛋白质的纯度、结晶性和绝对量均有比较高的要求,限制了其广泛应用.交联质谱技术是近十多年来发展起来的新技术,它将质谱技术与交联技术相结合,在研究蛋白质结构与相互作用方面具有速度快、成本小、蛋白质各方面性状要求低等优势.本文就交联质谱技术各个环节的技术方法加以综述,包括交联质谱实验分离富集技术、常见交联剂特性、交联质谱数据库搜索算法、结果验证研究和交联质谱技术的应用等方面,并展望了该研究方向未来的发展.     

现代代谢组学平台建设及相关技术应用

代谢组作为生命科学研究的5个层面(基因组、转录组、蛋白质组、代谢组和表型组)之一越来越受到科研工作者的关注。色谱–质谱联用技术由于其高分离能力、高灵敏度等优点在代谢组学(定性和定量)领域发挥重要的作用,基于色谱–质谱联用技术的代谢组学已成功应用于代谢表型差异研究、基因功能鉴定和转基因生物安全性评价等多个研究方向。本文以中国科学院遗传与发育生物学研究所代谢组学平台为例,详细介绍了现代代谢组学平台色谱–质谱联用仪器的硬件组成,以及不同技术平台在现在系统生物学研究中的具体应用。     

Analysis of nucleic acids by ion-spray mass spectrometry

We analyzed various synthetic oligonucleotides with the use of ion-spray mass spectrometer. The most suitable conditions were investigated for analyzing oligonucleotides with molecular weights ranging from 3000 to 15000. We have found that the pH of the solvent was critical to reduce the formation of adduct ions in the mass spectra. Tandem mass spectrometry was also used to study the sequences.     

Analysis and purification of synthetic oligonucleotides by reversed-phase high-performance liquid chromatography with photodiode array and mass spectrometry detection.

Native and modified synthetic oligonucleotides were purified by reversed-phase HPLC using volatile ion-pairing mobile phases. Purification of 10-90 nmol of oligonucleotides in a single injection was demonstrated using a 4.6 x 75-mm HPLC column packed with porous 2.5 microm C18 sorbent. Separation of target products from N-1 failure fragments was achieved for oligonucleotides in the 4- to 60-mer size range. We employed a combination of absorbance and mass spectrometry detection to identify by-products of oligonucleotide synthesis. This method was also employed for analysis and purification of fluorescently labeled oligonucleotides.     

Site-specific incorporation of the 1-hexanol-1,N6-etheno-2'-deoxyadenosine adduct into oligodeoxyribonucleotides

Modified oligonucleotides that contain the hydrophobic 1-hexanol-1,N(6)-etheno-2'-deoxyadenosine adduct have been synthesized using a mild solid phase phosphoramidite chemistry. The presence and the integrity of the modified nucleoside in the synthetic oligomers were confirmed by electrospray ionization and MALDI mass spectrometry measurements together with analysis of the complete enzymatic hydrolysate by high performance liquid chromatography coupled to UV and fluorescent detection techniques.     

Negative electrospray ionization mass spectrometry of synthetic and chemically modified oligonucleotides.

We report here on the analysis of synthetic oligonucleotides by electrospray ionization mass spectrometry (ESI-MS). After intensive removal of salt ions (especially sodium cations), negative ion mass spectra, allowing mass measurement with an accuracy of 0.01%, were obtained on several oligonucleotides up to 80 nucleotides. In most cases, the resolution was sufficient to observe n-1 and n-2 forms due to internal deletions during automated synthesis, and to identify the missing nucleotides. A 132-mer, whose size is close to the limit of automated chemical synthesis, was also successfully mass measured. A quantitative study showed that ESI-MS can provide quantitative data on oligonucleotides of similar size and structure. The described methodology is used to characterize oligonucleotide analogues such as phosphorothioate oligonucleotides designed for antisense applications. Finally, analyses in the positive ion mode on a trimer TpTpT in the presence of different amine bases were performed and allowed a better understanding of the influence of these bases on the ions formation.     

An automated algorithm for sequence confirmation of chemically modified oligonucleotides by tandem mass spectrometry

We have developed a tandem mass spectrometry (MS/MS) data analysis program for confirmation of sequence of chemically modified oligonucleotides. The method is based on the analysis of deconvoluted MS/MS data for fragment ions from three charge states and comparison of these data against a set of computer-generated masses from expected fragmentation patterns. The algorithm compares the experimental masses not only against the fragment set predicted for the expected sequence but also against a wider test set covering all next-neighbor position switches of the original sequence and all pairwise swaps of nucleosides, which in synthesis would result in molecules with masses within a preset mass tolerance. The algorithm is capable of identifying incorrect sequences that would not be distinguished by identity testing with electrospray ionization mass spectrometry. The method has been tested with permutations of the two 21-mer single strands of a chemically modified short interfering RNA containing 2′-O-methyl and phosphorothioate linkages. For both strands, challenge sequences were synthesized and tested with the premise that they were the original sequences. The algorithm correctly reported the locations of next-neighbor position switches and nucleoside swaps. The results confirm the approach as useful for MS/MS-based identity test methods for synthetic oligonucleotides.     

Characterization of synthetic oligonucleotides containing biologically important modified bases by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Oligonucleotides containing modified bases are commonly used for biochemical and biophysical studies to assess the impact of specific types of chemical damage on DNA structure and function. In contrast to the synthesis of oligonucleotides with normal DNA bases, oligonucleotide synthesis with modified bases often requires modified synthetic or deprotection conditions. Furthermore, several modified bases of biological interest are prone to further damage during synthesis and oligonucleotide isolation. In this article, we describe the application of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) to the characterization of a series of modified synthetic oligonucleotides. The potential for and limits in obtaining high mass accuracy for confirming oligonucleotide composition are discussed. Examination of the isotope cluster is also proposed as a method for confirming oligonucleotide elemental composition. MALDI-TOF-MS analysis of the unpurified reaction mixture can be used to confirm synthetic sequence and to reveal potential problems during synthesis. Analysis during and after purification can yield important information on depurination and base oxidation. It can also reveal unexpected problems that can occur with nonstandard synthesis, deprotection, or purification strategies. Proper characterization of modified oligonucleotides is essential for the correct interpretation of experiments performed with these substrates, and MALDI-TOF-MS analysis provides a simple yet extensive method of characterization that can be used at multiple stages of oligonucleotide production and use.     

Characterization of therapeutic oligonucleotides using liquid chromatography with on-line mass spectrometry detection

A method for the analysis and characterization of therapeutic and diagnostic oligonucleotides has been developed using a combination of liquid chromatography and mass spectrometry (LC-MS). The optimized ion-pairing buffers permit a highly efficient separation of native and chemically modified antisense oligonucleotides (AS-ODNs) from their metabolites or failure synthetic products. The mobile phases were MS compatible, allowing for direct and sensitive analysis of components eluting from the column. The method was applied for the quantitation and characterization of AS-ODNs, including phosphorothioates and 2'-O-methyl-modified phosphorothioates. Tandem LC-MS analysis confirmed the identity of the oligonucleotide metabolites, failure products, the presence of protection groups not removed after synthesis, and the extent of depurination or phosphorothioate backbone oxidation.     

The use of mass spectrometry in genomics

Recent advances in the development of electrospray ionization (ESI) and matrix-assisted laser desorption/ionization (MALDI) now permit the near routine analysis of oligonucleotides and intact nucleic acids. These developments have led to the use of mass spectrometry (MS) as a detection platform for genomics studies. Among the various uses of mass spectrometry in genomics, applications focused on the characterization of single nucleotide polymorphisms (SNPs) and short tandem repeats (STRs) are particularly well-suited to MALDI or ESI-based analysis. It is predicted that continued developments in methodology and instrumentation will further improve the capabilities of mass spectrometry for nucleic acid analysis.     

Determination of oligonucleotide molecular masses by MS-MALDI

MALDI mass spectrometry (MS) of 14- to 42-mer homogeneous oligonucleotides and their mixtures was carried out using a Vision 2000 instrument (Thermo BioAnalysis, Finnigan, United States). Conditions for the determination of oligonucleotide molecular masses were optimized by applying various matrices and operation modes. The most reproducible results with minimal uncontrolled decomposition of the oligonucleotides including their apurinization during the MALDI MS registration were obtained using 2,4,6-trihydroxyacetophenone as a matrix instead of 3-hydroxypicolinic acid, usually employed in the mass spectrometry of oligonucleotides. Our approach allows the determination of molecular masses of oligonucleotides obtained by chemical synthesis and the evaluation of their component composition and purity. It was applied to the mass spectrometric analysis of oligonucleotides containing a 3'-(methyl-C-phosphonate) group or a modified 1,N6-ethenodeoxyadenosine unit.     

Analysis of Polymerase Chain Reaction-Amplified DNA Products by Mass Spectrometry Using Matrix-Assisted Laser Desorption and Electrospray: Current Status

Recent advances in molecular biology are making it possible to diagnose genetic diseases and identify pathogens through the analysis of DNA. As clinical applications for molecular diagnosis increase, rapid, reliable methods for determination of DNA size will be needed. Mass spectrometry offers the potential of analyzing amplified DNA quickly and reliably, without the need for gel-based separation and sample labeling steps that are conventionally employed. Both electrospray ionization and matrix-assisted laser desorption/ionization have been evaluated for the size analysis of DNA using both synthetic oligonucleotides and PCR-amplified samples corresponding to bases 1626 to 1701 of the cystic fibrosis transmembrane conductance regulator gene. Both technologies have been demonstrated to have mass range and sensitivity required for the analysis of PCR-amplified DNA in this size range using minimal sample preparation. Steps required to incorporate either ionization technique into a reliable analytical scheme for the rapid, routine analysis of DNA are outlined.