数字PCR技术在核酸标准物质研制中的应用

在标准物质研制领域,生物标准物质的研制逐渐成为了研究热点,同时基于核酸的检测技术的开发与应用又推动了核酸标准物质的进程。核酸标准物质需要高级别、精准的定值方法,数字PCR作为单分子定量技术得到了广泛的应用。数字PCR是一种测定核酸分子的绝对定量方法,如微滴式数字PCR是采用油包水形成的微滴作为反应室,将含有DNA模板的反应溶液分配到大量独立的反应室中进行扩增反应,再通过统计反应室中的阳性信号来定量DNA的拷贝数,从而达到精确定量核酸拷贝数的目的。综述了近年来关于数字PCR及其在核酸标准物质研究领域的最新应用进展,重点综述了其在转基因检测、医疗诊断等领域的应用进展,以期为核酸标准物质的研制提供参考。     

实时定量PCR发展概述

实时定量聚合酶链反应(real-time quantitative polymerase chain reaction,简称qPCR)是一种通过荧光信号对PCR进程进行实时监测,并对未知模板进行定量分析的一种核酸定量技术,该技术在临床诊断和生命科学等多领域发挥着重要的作用。现就生物制品领域有着重要应用价值的中介探针聚合酶链反应(mediator probe polymerase chain reaction,MP PCR)和数字聚合酶链反应(digital polymerase chain reaction,dPCR)新技术加以介绍,同时也对qPCR技术中的关键因素(如参考基因选择和核酸质量评价)以及qPCR最低限度标准(minimum information for the publication of real-time quantitative PCR,MIQE)指南作一概述。     

数字PCR及其在现代医学分子诊断中的应用

数字PCR(digital PCR,dPCR)技术被认为是精确定量核酸分子的全新技术手段,因为具有较高的灵敏度和特异性等特点而得到迅速发展。数字PCR在临床上的多个领域展现出良好的应用前景,比如肿瘤液体活检、器官移植物损伤评估、无创产前筛查、病原微生物分子诊断以及二代测序文库质控和结果验证等。本文就数字PCR在上述领域中的应用研究及其进展进行综述。     

核酸定量检测方法研究进展

核酸相关的研究和应用广泛存在于各个学科领域,与之相关的核酸定量检测技术越来越受到研究人员的重视。本文对目前实验室广泛采用的和近几年进展迅速的核酸定量方法(包括紫外分光光度法、荧光染料法、实时荧光定量PCR法、数字PCR法等)进行介绍,着重阐述其检测原理和优缺点,为研究人员今后进行相关研究提供参考。     

数字PCR技术及其在检测领域的应用

随着分子生物学技术的不断发展和需求的多样化,用于核酸检测的各种PCR衍生技术应运而生。数字PCR是一种单分子水平的大规模分区扩增定量核酸检测技术。该技术以微腔室/微孔或微滴作为PCR反应器,无需校准物和绘制标准曲线即可实现对样品初始浓度的绝对定量,具有高灵敏度、高特异性和高精确度的特点。本文详细介绍了数字PCR的技术发展史、作用原理以及仪器平台类型,系统阐述了数字PCR在转基因检测、疾病诊断、环境及食品监管等方面的应用概况,并对该技术的应用前景进行了展望,以期对未来数字PCR的开发利用提供参考。     

数字PCR技术及其应用进展

数字PCR(Digital PCR,dPCR)是核酸绝对定量的新方法,该技术通过分液,将含有核酸模板的PCR反应体系分配到上万个反应器中进行PCR扩增,根据荧光信号的有或无,进行结果计数,通过泊松分布的统计处理,直接得出核酸的拷贝数。相比于实时荧光定量PCR(Quantitative PCR,qPCR),dPCR不需要建立标准曲线,应用前景更广。本文对dPCR的发展历史、原理及其应用进行了综述。     

数字PCR技术及其应用进展北大核心CSCD

数字PCR(Digital PCR,dPCR)是核酸绝对定量的新方法,该技术通过分液,将含有核酸模板的PCR反应体系分配到上万个反应器中进行PCR扩增,根据荧光信号的有或无,进行结果计数,通过泊松分布的统计处理,直接得出核酸的拷贝数。相比于实时荧光定量PCR(Quantitative PCR,qPCR),dPCR不需要建立标准曲线,应用前景更广。本文对dPCR的发展历史、原理及其应用进行了综述。     

癌症液体活检新思路：数字PCR检测DNA甲基化

癌症的早期诊断可提高患者生存率.微创采集人体体液的液体活检方法可避免传统肿瘤组织活检方法侵入性和异质性的问题,逐渐成为癌症诊断的新方式.另外,DNA甲基化作为预测癌症发生发展的标志物,引起了越来越多研究者的关注.但传统DNA甲基化的检测方法灵敏度不高,且容易出现假阳性.近年来,数字PCR技术因其超高的检测灵敏度和精确度、无需标准曲线即可进行核酸绝对定量检测的优势,被用于DNA甲基化的定量检测中.本文首先介绍了DNA甲基化与癌症发生发展的关系,总结了传统DNA甲基化检测方法及其在癌症临床诊断中的应用,阐述了基于不同核酸样本分散方法的数字PCR技术及其在微量DNA甲基化检测中的优势,总结了采用数字PCR技术检测癌症患者体液中DNA甲基化的具体步骤,列举了数字PCR技术在癌症DNA甲基化检测中的研究成果及应用进展,最后提出了数字PCR技术检测癌症DNA甲基化未来可能面临的挑战,并对数字PCR技术在癌症液体活检方面的应用前景进行了展望.     

数字PCR在功能核酸精准检测中的研究进展

数字PCR是近年来迅速发展起来的一种定量分析技术。该技术结果判定不依赖于扩增曲线的循环阈值(Ct),不受扩增效率的影响,具有很好的准确度和重现性,并且可以实现绝对定量分析。数字PCR已经在功能核酸检测、鉴定等研究领域显示出巨大的技术优势和应用前景。在对数字PCR技术的基本原理和定量方法介绍的基础上,对该技术在功能核酸检测的主要应用领域进行综述,并对数字PCR在功能核酸检测领域中的研究前景做出了展望。     

数字PCR定量检测血浆中环状RNA方法的建立

生物标志物一直是医学领域的研究热点.目前主要以实时荧光定量PCR技术作为分子诊断的检测手段,用于大样本的核酸检测,但该技术具有限制性,会导致假阴性.作为第三代PCR的数字PCR技术,优化并提高了检测灵敏度,无需标准曲线实现绝对定量检测,大大提高了检测的精准度,尤其是对于低表达RNA的检测,显得更为出色.本研究以hsa_circ_0061276为例,利用微滴式数字PCR EvaGreen染料法对血浆中hsa_circ_0061276的拷贝数进行绝对定量地检测,成功检测出胃炎和胃癌患者血浆中hsa_circ_0061276的具体拷贝数.因此,数字PCR作为新型检测技术在临床实际应用中有较大推广价值.     

数字PCR在新型冠状病毒检测中的应用前景

2020年,由新型冠状病毒（SARS-CoV-2）导致的新型冠状肺炎（COVID-19）疫情在世界各国大规模爆发,导致全球公共卫生安全受到巨大影响。目前广泛采用的荧光定量PCR（RT-PCR）在检测SARS-CoV-2方面存在可能出现“假阴性”结果、需多次取样、重复检测等缺点,亟需建立一种灵敏度更高、样本用量少、操作简单的检测技术,以快速、准确、高效的筛选出新型冠状肺炎患者。数字PCR为新兴痕量核酸分子技术,具有灵敏度高、耐受性强、可绝对定量等优点,在病毒检测领域中广泛应用。介绍了SARS-CoV-2病原学特征和荧光PCR检测SARS-CoV-2目前存在的主要问题,并对数字PCR在SARS-CoV-2检测中的应用前景进行了具体阐述,以期为后续开发更高效的检测试剂盒、提高检测准确性提供方案。     

A decade with nucleic acid‐based microbiological methods in safety control of foods

In the last decade, nucleic acid‐based methods gradually started to replace or complement the culture‐based methods and immunochemical assays in routine laboratories involved in food control. In particular, real‐time polymerase chain reaction (PCR) was technically developed to the stage of good speed, sensitivity and reproducibility, at minimized risk of carry‐over contamination. Basic advantages provided by nucleic acid‐based methods are higher speed and added information, such as subspecies identification, information on the presence of genes important for virulence or antibiotic resistance. Nucleic acid‐based methods are attractive also to detect important foodborne pathogens for which no classical counterparts are available, namely foodborne pathogenic viruses. This review briefly summarizes currently available or developing molecular technologies that may be candidates for involvement in microbiological molecular methods in the next decade. Potential of nonamplification as well as amplification methods is discussed, including fluorescent in situ hybridization, alternative PCR chemistries, alternative amplification technologies, digital PCR and nanotechnologies.     

数字PCR技术及应用研究进展

数字PCR是继实时定量PCR之后新兴发展起来的一种绝对定量分析技术。通过将单个DNA分子转移入独立的反应室,PCR扩增反应后,对荧光信号进行检测分析,实现单分子的绝对定量。数字PCR技术摆脱了对标准曲线的依赖,具有更高灵敏度和准确度,在基因突变检测、拷贝数变异检测、微生物检测、转基因食品检测以及下一代测序等方面均得到广泛应用。本文介绍数字PCR技术的定量方法,并评述该技术在主要应用领域的研究进展。     

Molecular Identification of Nanoplanktonic Protists Based on Small Subunit Ribosomal RNA Gene Sequences for Ecological Studies1

Nanoplanktonic protists are comprised of a diverse assemblage of species which are responsible for a variety of trophic processes in marine and freshwater ecosystems. Current methods for identifying small protists by electron microscopy do not readily permit both identification and enumeration of nanoplanktonic protists in field samples. Thus, one major goal in the application of molecular approaches in protistan ecology has been the detection and quantification of individual species in natural water samples. Sequences of small subunit ribosomal RNA (SSU rRNA) genes have proven to be useful towards achieving this goal. Comparison of sequences from clone libraries of protistan SSU rRNA genes amplified from natural assemblages of protists by the polymerase chain reaction (PCR) can be used to examine protistan diversity. Furthermore, oligonucleotide probes complementary to short sequence regions unique to species of small protists can be designed by comparative analysis of rRNA gene sequences. These probes may be used to either detect the RNA of particular species of protists in total nucleic acid extracts immobilized on membranes, or the presence of target species in water samples via in situ hybridization of whole cells. Oligonucleotide probes may also serve as primers for the selective amplification of target sequences from total population DNA by PCR. Thus, molecular sequence information is becoming increasingly useful for identifying and enumerating protists, and for studying their spatial and temporal distribution in nature. Knowledge of protistan species composition, abundance and variability in an environment can ultimately be used to relate community structure to various aspects of community function and biogeochemical activity.     

Sensitive detection of mycoplasmalike organisms in field-collected and in vitro propagated plants of Brassica, Hydrangea and Chrysanthemum by polymerase chain reaction

A polymerase chain reaction (PCR) protocol, previously designed for amplification of a DNA fragment from aster yellows mycoplasmalike organism (MLO), was employed to investigate the detection of MLO DNA in field-collected and in vitro micropropagated plants. PCR with template DNA extracted from symptomatic, naturally-infected samples of Brassica, Chrysanthemum and Hydrangea, each yielded a DNA band corresponding to 1.0 Kbp. However, no DNA product was observed when either infected Ranunculus (with phyllody disease) or Gladiolus with (symptoms of ‘germs fins’) was used as source of template nucleic acid for PCR; further experiments indicated absence of target DNA in the case of Ranunculus and the presence of substances in Gladiolus which inhibited the PCR. The MLO-specific DNA was detected by PCR using less than 95 pg of total nucleic acid (equivalent to total nucleic acid from 1.9, ug tissue) in the case of field-collected Hydrangea and less than 11.4 pg of nucleic acid (equivalent to total nucleic acid from 19 ng of tissue) in the case of field-collected Brassica. The findings illustrate highly sensitive detection of MLOs in both field-grown and in vitro micropropagated infected plants.