免提核酸的高通量DNA检测技术

目的介绍一种基于捕获的高通量DNA检测技术,无需核酸提取,适用于不同样品的各种应用,以提供遗传分析有力的技术手段。方法全血、唾液、干血斑和口腔拭子等样品裂解后释放DNA,经热变性后,通过与一系列特异探针杂交使靶DNA被捕获至96孔板;洗去未结合探针后,直接利用特异性引物进行荧光定量扩增(qPCR),或用酶连接连续排列的杂交探针,形成两端为特定序列的单链DNA模板,最后用通用引物进行qPCR分析;以全血中P16基因为靶标评估免提核酸技术的DNA检测效果,并将其应用于全血、血清及干血片样品中寄生虫DNA的检测,评估其灵敏度和特异性,同时评估了不同储藏方法下唾液及口腔拭子DNA检测的稳定性。结果成功应用于全血、干血斑、唾液、口腔拭子等多种样品的DNA检测;无需核酸提取,唾液及拭子样品在室温及4℃下保存15 d后检测仍具有较高的稳定性;该方法对疟原虫的检测下限低至0.06个疟原虫/μL,较传统镜检具有更高的灵敏度,可准确检测到被感染样品中的寄生虫DNA。结论建立了无需核酸提取的高通量DNA检测技术,适用于不同样本类型及靶标检测,为大规模基因筛查分析提供一个灵敏、高效的工具。     

基于茎环引物探针法定量检测乙型肝炎病毒miR-3的方法学建立

目的:本研究拟通过广泛筛选特异性引物探针组,建立一套乙型肝炎病毒(HBV)微小RNA-3(miR-3)的绝对定量PCR检测方法。方法:基于茎环引物RT-qPCR方法原理,设计茎环引物进行逆转录,结合SYBR Green法qPCR进行特异性初筛,选择特异性较佳的引物组,再结合TaqMan MBG探针,确定最佳的引物探针组,实现对HBV miR-3的定量检测。结果:共设计和测试了25套茎环引物组,利用基于SYBR Green的RT-qPCR方法,筛选出6套具有良好特异性的引物组,并进一步针对这些引物组设计和测试了相应的探针,获得了可精准定量HBV miR-3的引物探针组。测试结果表明,该引物探针组不但保证了高特异性,而且定量线性范围达到每个反应102～108拷贝,其扩增效率约为88%。结论:本研究确立了一套可用于绝对定量检测HBV miR-3的特异性引物探针组。     

重组酶介导恒温扩增技术检测疟原虫方法的建立?

本研究利用重组酶介导恒温扩增RAA技术，建立了一种快速检测疟原虫的方法。选取疟原虫18S rDNA序列，设计了检测疟原虫的通用引物，并对引物进行筛选和特异性检测。筛选出4组扩增效果较好的引物。该方法整个反应过程在37℃下进行，扩增时间短（40 min），并具有良好的特异性。结果表明，成功建立了一种检测疟原虫的RAA法，并且该方法适合于进出口岸疟原虫的快速检测。     

2012年发现的新冠状病毒分子检测方法的建立与探针优化

目的 建立2012年确定的新冠状病毒的分子检测方法,并筛选优化引物与探针.方法 依据最先发表的208 bp长的新冠状病毒1b片段核酸序列,比对分析后设计合成常规RT-PCR引物1对及荧光定量RT-PCR引物1对与TaqMan探针2条(TZ1,TZ2),同时合成锁核酸修饰的TaqMan探针2条(LNA-TZ1,LNA-TZ2).建立检测新冠状病毒感染的常规RT-PCR方法与4种荧光定量RT-PCR,分析比较其灵敏度与特异性,同时参照欧洲发表的2种荧光定量RT-PCR引物与探针对(upE,ORF1b)建立相应方法,以合成的阳性模板比较6对荧光定量RT-PCR引物与探针的检出灵敏度.结果 所合成的常规RT-PCR与荧光定量RT-PCR引物与探针皆有较好特异性,不能扩增其他人冠状病毒模板及常见呼吸道病毒模板,检出下限达50 ～ 500拷贝/反应.锁核酸修饰TaqMan探针可改善荧光定量PCR检测方法的反应性能,经锁核酸修饰的TaqMan探针与常规TaqMan探针相比,检出率提高10倍左右,其中LNA-TZ1与upE探针对具最佳反应性能.结论 本研究所建立的常规RT-PCR与荧光定量RT-PCR可用于新冠状病毒的分子检测,并推荐使用LNA-TZ1与upE探针对.本研究为新冠状病毒分子检测方法应用与改进奠定了基础.     

TaqMan探针实时PCR检测人MTHFR基因C677T多态性方法的建立

目的建立TaqMan探针实时PCR检测人MTHFR基因C677T多态性的方法。方法设计一对MTHFR基因C677T多态位点的引物及TaqMan探针,采用TaqMan探针实时PCR扩增SNP分型方法检测唇腭裂患者及其父母共100人的MTHFR基因C677T多态性,与常规PCR-RFLP方法进行一致率比较,并对其特异性、敏感性和重复性以及成本-效益等进行评价,同时对部分实时PCR产物样本进行测序验证。结果运用TaqMan探针实时荧光PCR技术对MTHFR基因C677T多态性检测结果准确,特异性好,与常规PCR-RFLP方法结果具有高度一致性,Kappa=0.922>0.75(P=0.000);检测灵敏度可达2×103拷贝;重复性好、高通量、无污染、安全性好;随机样品TaqMan探针分型结果与测序结果完全一致。结论成功建立了TaqMan探针实时PCR检测人MTHFR基因C677T多态性的方法;此方法是常规临床诊断及大规模群体研究的良好平台。     

微板酶联夹心杂交法定量检测人IL-18 mRNA

目的：建立一种高灵敏度、高特异性、精确、简便的微孔板酶联夹心杂交技术，定量检测人IL-18mRNN。方法：针对人IL-18mRNA RT-PCR产物—条链的不同区域序列设计—对特异探针，其中一条为捕获探针，5’端为氨基修饰，可以与微量DNA结合板表面的NOS基团共价结合，“竖直”地包被在微孔板内；另一条为检测探针，3’端标记生物素。提取人外周血单个核细胞中总RNA，进行RT-PCR扩增IL-18 mRNA，产物热变性后加入已包被捕获探针的微孔板内进行杂交，再加入检测探针与已杂交的产物结合，最后经亲和素-辣根过氧化物酶(SAV-HRP)系统检测杂交信号。结果：该法检测IL-18mRNA RT-PCR产物的灵敏度明显高于琼脂糖凝胶电泳，重复性良好，且结果数据化。结论：该方法具有操作简单、灵敏度高、特异性强等优点，适合于PCR扩增产物的定量检测。     

一种可用于溶瘤病毒M1体内组织定量的TaqMan RT-qPCR检测法的建立与评价

目的:监测溶瘤病毒M1在组织中的传播情况,以更好地控制给药剂量,确保安全性。方法:建立一种基于TaqMan的实时定量PCR检测法,用于对组织中溶瘤病毒M1的检测和定量,并检测静脉注射病毒后多种实验动物体内的病毒载量和分布。结果:我们以一对特异的引物(Q3)和标准RNA开始SYBR Green RT-qPCR研究。通过优化实验方法发现当退火温度高于62℃时可降低基质效应,但却影响了扩增效率。因此我们建立了一步法TaqMan RT-qPCR实验,重新设计了一对Q3短引物(Q3S)。运用一步TaqMan RT-qPCR检测法和Q3S引物,在混有SD大鼠或食蟹猴基质RNA的背景下,均能特异性检测到低拷贝数的标准RNA。经验证,该方法适用于检测M1病毒在小鼠、SD大鼠和食蟹猴体内的组织分布。结论:利用Q3S引物构建的TaqMan一步法RT-qPCR能够定量检测不同动物不同组织样品中的M1病毒,具有特异性和敏感性,可进一步应用于临床样品的检测。     

一种可用于溶瘤病毒M1体内组织定量的TaqMan RT-qPCR检测法的建立与评价（英文）

目的:监测溶瘤病毒M1在组织中的传播情况,以更好地控制给药剂量,确保安全性。方法:建立一种基于TaqMan的实时定量PCR检测法,用于对组织中溶瘤病毒M1的检测和定量,并检测静脉注射病毒后多种实验动物体内的病毒载量和分布。结果:我们以一对特异的引物(Q3)和标准RNA开始SYBR Green RT-qPCR研究。通过优化实验方法发现当退火温度高于62℃时可降低基质效应,但却影响了扩增效率。因此我们建立了一步法TaqMan RT-qPCR实验,重新设计了一对Q3短引物(Q3S)。运用一步TaqMan RT-qPCR检测法和Q3S引物,在混有SD大鼠或食蟹猴基质RNA的背景下,均能特异性检测到低拷贝数的标准RNA。经验证,该方法适用于检测M1病毒在小鼠、SD大鼠和食蟹猴体内的组织分布。结论:利用Q3S引物构建的TaqMan一步法RT-qPCR能够定量检测不同动物不同组织样品中的M1病毒,具有特异性和敏感性,可进一步应用于临床样品的检测。     

不同黏膜上皮细胞中巨噬细胞炎性蛋白-3α转录水平的荧光定量RT-PCR比较分析

目的 定量比较分析不同黏膜上皮细胞中人巨噬细胞炎性蛋白-3α(MIP-3α)的转录水平.方法 体外转录制备MIP-3α RNA标准品,人工合成MIP-3α mRNA序列特异的引物及TaqMan探针.利用TaqMan EZ RT-PCR试剂盒的反应体系和ABI实时荧光定量PCR仪进行实时荧光定量RT-PCR.通过对RT-PCR产物测序、使用标准品和质控品进行多次独立测试等评估实时荧光定量RT-PCR方法的特异性、灵敏度和可重复性.随后对不同黏膜上皮细胞系Caco-2、T-84、HeLa和淋巴细胞系PM1中MIP-3α mRNA水平进行了定量检测.结果 建立了可用于MIP-3α mRNA水平定量检测的实时荧光定量RT-PCR方法,该方法特异性好(扩增片段测序结果与参考序列完全一致)、灵敏度高(25 μl反应体系中有5个拷贝就可以检出)、检测样品浓度范围广(103～1010拷贝/ml).对Caco-2、T-84、HeLa和PM1细胞中MIP-3α mRNA水平的定量分析表明,肠黏膜上皮细胞Caco-2和T-84的MIP-3α mRNA水平比HeLa和PM1细胞高.结论 黏膜上皮细胞能表达丰富的MIP-3α,不同黏膜上皮细胞MIP-3α的表达水平可能不同.     

PCR结合寡核苷酸探针杂交检测临床常见真菌的实验研究

目的 建立PCR结合生物标记的寡核甘酸探针斑点杂交技术,鉴定临床常见的真菌。方法 首先用真菌通用引物扩增白念球菌、热带念球菌、假热带念球菌、近平滑念球菌、光滑念球菌、解脂念球菌、克鲁斯念球菌、季也蒙念球菌、黄曲 霉、烟曲霉的核糖体大亚单位基因的保守区序列,然后用生物素标记的种特异性寡核苷酸探针与扩增产物杂交,并将此方法用于临床标本和临床分离菌株的检测。结果 通用引物可以扩增上述11种临床常见真菌的DNA,扩增片段长度在260bp左右。9种特异性探针分别与11种真菌标准菌株的PCR扩增产物杂交,结果表明每种探针都具有高度特异性。斑点杂交法和Southerm杂交法检测敏感性相同,为100fg;琼脂糖凝胶电泳法检测敏感性为1pg。通过69例临床标本和31例临床分析菌株的检测,PCR－杂交法的结果和真菌培养法的结果基本一致。结论 PCR结合生物素标记的寡核苷酸探针杂交技术可将9种临床常见真菌鉴定到种,方法快速、敏感、特异。     

2-Cys Peroxiredoxin TPx-1 is involved in gametocyte development in Plasmodium berghei

Peroxiredoxins (Prxs) constitute a ubiquitous family of antioxidant enzymes involved in diverse cellular functions including cell proliferation and differentiation. To investigate the physiologic role of typical 2-Cys Prx in malaria parasites (TPx-1), we disrupted this gene in the rodent malaria parasite Plasmodium berghei (pbtpx-1). The gene-disrupted parasite (Prx KO) developed normally in mouse erythrocytes and multiplied at a rate similar to that of the parent strain (WT) during the experimental period. The normal growth rate was not altered after 10 passages, and the level of 8-hydroxy-2'-deoxyguanosine, which accumulates in the parasite genome during the cell cycle, was similar between Prx KO and WT. These results suggest that TPx-1 does not prevent parasite DNA oxidation, in contrast to mammalian Prx, and that it is not essential for asexual parasite growth in mouse erythrocytes. However, Prx KO produced up to 60% fewer gametocytes, sexual-stage parasites involved in the transition between the mammalian host and the mosquito, than WT did. The peak of gametocytemia was also delayed; however, the male/female ratio of gametocytes and the exflagellation activity of male gametocytes were normal. These results suggest that TPx-1 is required for normal gametocyte development but does not affect the male/female gametocyte ratio or male gametogenesis. Although the mechanism by which PbTPx-1 contributes to gametocyte development remains unknown, these findings suggest, for the first time, the involvement of Prx in the sexual development of the malaria parasite.     

Sex- and stage-specific reporter gene expression in Plasmodium falciparum

For malaria transmission, Plasmodium parasites must successfully complete gametocytogenesis in the vertebrate host. Differentiation into mature male or female Plasmodium falciparum gametocytes takes 9-12 days as the parasites pass through five distinct morphologic stages (I-V). To evaluate the signals controlling the initiation of stage- and/or sex-specific expression, reporter constructs containing the 5'-flanking regions (FR) of seven genes with distinct expression patterns through gametogenesis were developed. The regulatory information present in the 5'-FR of each selected gene was found to be sufficient to drive appropriate sex- and stage-specific reporter gene expression. The transformed parasite lines also provide in vivo markers to identify gametocytes at specific stages, including a subpopulation of schizonts that express early gametocyte markers.     

Real-time RT-PCR assay for rapid and specific detection of classical swine fever virus: comparison of SYBR Green and TaqMan MGB detection methods using novel MGB probes

Real-time PCR is an accurate, rapid and reliable method that can be used for the detection and also for the quantitation of specific DNA molecules. The basic principle is the recurring measurement of a fluorescent signal, which is proportional to the amount of amplification product. In our trial two detection systems were tested for classical swine fever virus (CSFV) detection and for its discrimination from other pestiviruses; non-specific dsDNA-binding dye SYBR Green and specific fluorogenic TaqMan MGB probes. Real-time RT-PCR assays were evaluated for diagnostic sensitivity and specificity by different pestiviral reference and field strains. With both approaches, SYBR Green and TaqMan probes, respectively, all of the CSFV strains isolated on cell culture were detected and also clearly distinguished from other pestiviruses. However, the established one-step real-time TaqMan RT-PCR assay was shown to be more appropriate for pestivirus quantitation, it reduces the risk of contamination and is less time consuming.     

SYBR Green Ⅰ联合TaqMan荧光定量PCR检测HBV-DNA的意义

目的探索SYBR GreenⅠ联合TaqMan荧光定量PCR检测HBV-DNA的意义。方法选择浓度为10^8.48、10^5.70和10^3.70copies/ml的3种HBV-DNA阳性血清和〈1×10^3.0copies/ml的阴性血清各1份,在TaqMan-PCR混合反应体系中加入SYBR Green Ⅰ组成双荧光PCR（TaqMan＋SYBR Green Ⅰ组）,同时进行TaqMan和SYBR Green Ⅰ的单荧光PCR（分别为TaqMan组和SYBR Green Ⅰ组）,设置同一PCR和熔解曲线的循环参数,检测HBV-DNA含量及其Tm,每种方法一次检测每份血清5次。结果TaqMan＋SYBR Green Ⅰ组检测的HBV-DNA阳性血清均为阳性,其平均含量为10^8.55±0.32、10^5.79±0.29、10^3.81±0.30,与TaqMan组的10^8.49±0.31、10^5.69±0.34、10^3.72±0.26copies/ml0.320.290.300.310.300.25对应浓度值取10对数比较,无统计学意义（t=0.31、0.54和0.27,P〉0.05）;与SYBR Green I组的10^8.41±0.35,10^5.21±0.34和10^3.26±0.26copies/ml（不含未检出的两次血清）比较,除高浓度外,中低浓度有统计学意义（t=2.90和0.340.262.62,P〈0.05）。TaqMan＋SYBR Green I组和SYBR Green Ⅰ组阳性血清均出现明显熔解曲线,熔解温度（Tm）分别为71.8℃、72℃和79.8℃,阴性血清未出现扩增曲线和Tm值。结论SYBR Green Ⅰ联合TaqMan-PCR检测HBV-DNA时,具有能维持TaqMan-PCR的高灵敏度、特异性更强,并能同时检测HBV-DNATm的特点,为HBV的DNA多态性分析,尤其是在HBV基因分型方面提供了新的检测思路。     

Parasitemia characteristics of Plasmodium vivax malaria patients in the Republic of Korea

Parasitemia characteristics of Plasmodium vivax malaria in temperate regions may differ from those in tropical zones. However, most parasitological and clinical features of P. vivax malaria have been investigated in the latter. In this study, we investigated 383 malaria patients to clarify the parasitemia characteristics of a P. vivax strain in the Republic of Korea (ROK). The mean parasitemia (8,396/μL) was less than half of tropical P. vivax malaria, and multiple invasions of erythrocytes were not rare (53.5% of the patients, 2.4% of the total investigated RBCs), but less than the observations in tropical zones. The intervals between the first symptom onset and diagnosis were significantly longer in gametocyte (+) patients than in gametocyte (-) patients. Only half of the total patients had both genders of gametocytes (191 of 353), and the male gametocyte density (169/μL) was lower than that of P. vivax strains of a previous study. Multiple invasions of erythrocytes and gametocytemia were coincident factors of the degree of anemia in P. vivax malaria. The present findings demonstrate the P. vivax strain in ROK reveals relatively low parasitemia and low male to female gametocyte ratio. The low ratio may be related with low transmission efficacy.     

Quantification of Plasmodium falciparum gametocytes in differential stages of development by quantitative nucleic acid sequence-based amplification

Two quantitative nucleic acid sequence-based amplification assays (QT-NASBA) based on Pfs16 and Pfs25, have been developed to quantify sexual stage commitment and mature gametocytes of Plasmodium falciparum. Pfs16 mRNA is expressed in all sexual forms including sexually committed ring stages while expression of Pfs25 mRNA is restricted to late stage gametocytes. Both assays showed a sensitivity of one sexual stage parasite/microl of blood. Blood samples from experimentally infected non-immune human volunteers were tested for Plasmodium falciparum by standard microscopy, a previously developed asexual 18S rRNA QT-NASBA, Pfs16 and Pfs25 mRNA QT-NASBA. Pfs16 QT-NASBA was positive in 9 out of 10 volunteers within 48 h after first detection of 18S rRNA, mostly before or at the day of positive microscopy. In contrast, the Pfs25 mRNA QT-NASBA was negative during the 28 days of follow-up, but consistently positive in gametocyte samples from naturally infected Kenyan patients. These data suggest that sexual stage commitment can occur early in the blood-stage infection without successful maturation into infectious gametocytes. In conclusion, Pfs16 and Pfs25 QT-NASBA assays in combination with a previously developed asexual stage QT-NASBA allow for the separate quantification of all developmental stages present in the circulation. The application of sexual stage QT-NASBA assays may contribute to a better understanding of the biology and epidemiology of malaria transmission.