HIV-1型前病毒基因检测芯片的研制及应用

目的研制艾滋病病毒1型(HIV-1)前病毒基因检测芯片，并将其应用到临床样本的检测中。方法合成多对引物，经筛选实验后选出6对适宜的引物用于逆转录-聚合酶链反应(RT—PCR)，扩增HIV基因组gag区(保守区)6个HIV目的基因片段，扩增小鼠GAPDH基因片段作为阳性内参片段，PCR扩增辣椒红素基因片段作为阴性对照片段。将上述片段克隆到pMD18-T载体上，从中选取3个HIV-1目的片段、阳性对照片段和阴性对照片段进行PCR扩增，扩增产物经纯化后点在尼龙膜上，制备成核酸检测芯片。地高辛PCR标记样本核酸与芯片杂交后，用酶联显色，分析结果。结果共检测了98份阳性样本和30个阴性样本，敏感性达93．9％，特异性为100．0％。结论该HIV-1前病毒基因检测芯片成本较低，具有较高的特异性和灵敏度，可以用于HIV-1感染和母婴传播的早期诊断。     

中国肠产毒性大肠杆菌中耶尔森菌强毒力岛的检测

目的　了解耶尔森菌强毒力岛在中国肠产毒性大肠杆菌中的分布及插入位点。方法　使用PCR扩增、DNA打点杂交和DNA测序及分析方法。结果　在 94株分离自中国的肠产毒性大肠杆菌中 ,14株耶尔森菌强毒力岛核心区的 8个基因PCR扩增阳性 ,除 3株菌的整合酶基因外 ,PCR扩增产物长度均与预期一致 ,但天冬酰胺转运RNA(asnTtRNA)位点扩增阴性 ;上述 14株菌进行全菌DNA打点杂交试验 ,均与irp2和 fyuA探针杂交 ;选择上述 3株菌中的 1株 ,对其整合酶基因的PCR产物测序 ,并与鼠疫耶尔森菌强毒力岛的整合酶基因序列比较 ,发现该整合酶基因于 5’端缺失了 347bp的片段。 结论　 14 %肠产毒性大肠杆菌携带的耶尔森菌强毒力岛 ,且均插入在天冬酰胺转运RNA位点处 ;部分菌株所携带的耶尔森菌强毒力岛的整合酶基因发生了缺失。     

志贺菌耐多药相关基因水平转移的验证及其耐药性研究

目的对志贺菌耐多药相关基因(T1C4)水平转移进行验证,并对其与细菌耐药性的关系进行初步判定。方法培养已筛选出的包含T1C4基因片段的阳性克隆,提取其质粒,PCR扩增T1C4基因片段、纯化、制备探针,与志贺菌敏感株SS23、志贺菌耐多药转移株(ST11)、大肠埃希菌耐多药株(E667)的基因组DNA和质粒DNA进行斑点杂交。采用药敏纸片法研究含T1C4基因片段大肠埃希菌的耐药性。结果应用PCR方法可以从ST11和E667菌株基因组DNA中扩增出T1C4基因片段,而SS23菌株不含该基因片段;应用T1C4基因探针进行斑点杂交显示,ST11和E667菌株的全基因组和质粒DNA均可显示杂交信号,而SS23菌株的基因组和质粒DNA均不产生杂交信号;14种药物的药敏试验表明,含有T1C4基因的大肠埃希菌(DH5α)对四环素、先锋V、头孢噻吩、氟哌酸、复方新诺明等五种药物的抑菌环直径明显小于(相差3mm以上)不含T1C4基因的DH5α菌株。结论 T1C4基因片段为ST11菌株从E667菌株获得,且存在于两菌株的质粒上;T1C4基因可能介导细菌对多种药物的抗性。     

鼠疫耶尔森氏菌inv基因中IS1541的研究及应用

目的　了解鼠疫耶尔森氏菌 inv基因中 IS15 41的插入情况 ,为鼠疫耶尔森氏菌的鉴别诊断提供依据。方法　 PCR反应及 Southern杂交分析。结果　对来自不同疫源地的 5 0株鼠疫耶尔森氏菌的 inv基因中部分序列进行扩增 ,均可扩出一条长为 10 0 0 bp的片段 ,用 IS15 41作探针 ,对其进行 Southern杂交分析 ,杂交结果无差别 ,而对照菌株除假结核耶尔森氏菌扩出一条长约 30 0 bp左右的片段外 ,其它均为阴性。结论　鼠疫耶尔森氏菌 inv基因高度同源 ,其间均有 IS15 41插入 ;该方法有助于鼠疫耶尔森氏菌与其它菌株的鉴别诊断     

PCR结合长臂光敏生物素探针检测粪便中志贺氏菌

本文报告了聚合酶链反应(PCR)结合长臂光敏生物素探针检测出腹泻病患者粪便中志贺氏菌。选择志贺氏菌和侵袭性大肠杆菌(EIEC)共有的DNA序列;质粒编码的侵袭相关焦点(ial)作为靶序列,PCR检测9株志贺氏菌,均扩增出320bp DNA片段,。19株非志贺氏菌均阴性。敏感试验显示其最小检菌量为100 cfu。58份粪际本中,23份阳性(39.6％),粪培养18份阳性(31％)。PCR敏感性高于粪培养8.6％。用长臂光敏生物素标记福氏2a扩     

PCR-ELISA微孔板杂交技术检测结核杆菌DNA

目的　采用PCR ELISA微孔板杂交技术检测结核杆菌DNA。方法 采用PCR技术扩增结核杆菌DNA，并将扩增产物加入预先包被结核杆菌探针的微孔板，再加入结核杆菌显色探针，同时进行微孔板核酸夹心杂交ELISA显色。共检测肺部疾病患者痰标本 510例。结果 该法的灵敏度为 59.3%，特异性为 95.0%；阳性预测值为 96.3%，阴性预测值为 51.4%。结论 PCR ELISA微孔板杂交技术可快速、准确地检测结核杆菌DNA，是结核病早期诊断和鉴别诊断的可靠实验室方法。     

实时荧光定量PCR检测五日热巴通体

目的 采用TaqMan-MGB探针建立检测五日热巴通体的实时荧光定量PCR（real-time quantitative PCR）方法。方法 根据五日热巴通体特异的16-23S rRNA间隔区序列设计引物和探针，以克隆的16-23S rRNA间隔区基因片段作DNA模板，建立了检测五日热巴通体实时荧光定量检测方法。结果 建立的定量标准曲线的循环阈值（Ct）与模板拷贝数呈良好的线性关系（r=0．996）；与普通PCR相比较，荧光定量PCR检测的灵敏度约为它的200倍。用荧光定量PCR检测其它相关立克次体和细菌，检出结果为阴性。实时荧光定量PCR检测五日热巴通体实验感染小鼠血、脾脏、肝脏和肺组织DNA样本，脾脏和肝脏样本中检出较高水平五日热巴通体DNA，血和肺部检出的目的DNA的水平较低。结论 本研究建立的检测五日热巴通体的实时荧光定量PCR法具有很高的检测灵敏度和特异性，可用于临床患者血样本的检测，作五日热的早期诊断。     

用聚合酶链反应技术鉴别恶性疟原虫不同地理株的初步研究

目的 阐明Fccl/HN株与云南株间的不同生物学特性。方法 用M26-32作探针，筛选恶性疟原虫cDNA基因表达文库，根据所获得的靶抗原决定簇表位的基因序列设计引物，分别进行PCR扩增；地高辛酶促生物标记Fccl-HN株DNA的PCR扩增产物，分别与Fccl/HN株DNA，云南株DNA和阳性克隆511的扩增产物杂交。结果 PCR扩增后Fccl/HN株DNA在约500bp和450bp处有2条特异性条带；云南株DNA在约500bp处有1条较淡的条带和1300bp处一较亮的特异性条带，阳性克隆511仅在约500bp处有1条特异性条带，标记探针能与克隆DNA，恶性疟原虫Fccl/HN株和云南株的PCR扩增产物杂交。结论 恶性疟原虫Fccl/HN株与云南株在基因组DNA结构上可能存在差异。     

PCR在沙门氏菌肠炎快速诊断中的应用

选择沙门氏菌共同的侵袭基因(invA)作为靶序列,用聚合酶链反应(PCR)直接检测腹泻病粪便中沙门氏菌。PCR检测10株沙门氏菌,均扩增出invA基因中284bp DNA片段,20株非沙门氏菌均阴性。敏感试验显示,其最小检菌量为8个细菌/ml,DNA最小检出量为100fg。PCR检测84份腹泻粪标本,13份阳性,其中10份粪培养阳性,3份粪培养阴性。     

PCR—ELISA微孔板杂交技术检测结核杆菌DNA

目的 采用PCR-ELISA微孔板杂交技术检测结核杆菌DNA。方法 采用PCR技术扩增结核杆菌DNA，并将扩增产物加入预先包被结核杆菌探针的微孔板，再加入结核杆菌显色探针，同时进行微孔板核酸夹心杂交ELISA显色。共检测肺部疾病患者痰标本510例。结果 该法的灵敏度为59．3％，特异性为95．0％；阳性预测值为96．3％，阴性预测值为51．4％。结论 PCR-ELISA微孔板杂交技术可快速、准确地检测结核杆菌DNA，是结核病早期诊断和鉴别诊断的可靠实验室方法。     

检测贝氏柯克斯体的实时荧光定量PCR

目的采用新型TaqMan-MGB探针建立检测贝氏柯克斯体的实时荧光定量PCR(real-timequantitativePCR)方法。方法根据贝氏柯克斯体特异的23SrRNA插入基因序列设计引物和探针,以克隆的23SrRNA插入基因片段作DNA模板,在荧光定量PCR检测仪(ABI7900型)上建立实时荧光定量检测方法。结果建立的定量标准曲线的循环阈值(Ct)与模板拷贝数呈良好的线性关系(r=0.997);与套式PCR相比较,荧光定量PCR检测敏感性是其100倍。用荧光定量PCR检测其它相关立克次体,检出结果均为0。用荧光定量PCR检测贝氏柯克斯体感染的小鼠脾脏标本,脾脏中贝氏柯克斯体的感染量与感染过程具有相关性。结论本研究建立的检测贝氏柯克斯体的实时荧光定量PCR具有很高的特异性和敏感性,特别适合样本中微量贝氏柯克斯体DNA的检测,其定量检测可用于动物实验中的贝氏柯克斯体感染程度的分析。     

16SrRNA基因PCR加反相杂交技术检测细菌DNA

目的探讨聚合酶链反应（ＰＣＲ）加反相杂交技术在细菌ＤＮＡ检测中的应用。方法以１６ＳｒＲＮＡ基因为靶序列，设计引物及寡核苷酸探针，采用ＰＣＲ法加反相杂交检测标准菌株及临床标本细菌ＤＮＡ。结果对２０株不同标准菌株进行ＰＣＲ扩增，均出现３７１ｂｐ长度的ＤＮＡ片段，敏感性试验可检测出１０－１２ｇ的细菌ＤＮＡ，与人基因组及病毒无交叉反应；２２份血培养阳性标本及４份脑脊液培养阳性标本均扩增出３７１ｂｐ长度ＤＮＡ条带，反相杂交区分革兰阳性／阴性细菌与培养结果相符。结论１６ＳｒＲＮＡ基因ＰＣＲ加反相杂交技术检测细菌ＤＮＡ，具有敏感、快速、准确的特点，为细菌感染的临床诊断提供了科学的依据。     

Polymerase chain reaction with double primer pairs for detection of human parvovirus B19 induced aplastic crises in family outbreaks.

Parvovirus B19 DNA can be detected by polymerase chain reaction with double primer pairs (nested PCR). Recent infection was documented by a retrospective serological study using Parvoscan-B19 enzyme linked immunosorbent assay (EIA) for detection of B19 human parvovirus IgM and IgG antibodies in serum or plasma specimens. In 3 families B19 outbreaks caused aplastic crises necessitating blood transfusion in 5 children and 1 adult with hereditary sphaerocytosis. Four members from 2 of the families had clinically overt haemolytic anaemia prior to the event. Two members in another family presented with an aplastic crisis disclosing the underlying chronic haemolytic disease. All 7 patients were identified as PCR positive in serum samples taken 3-14 days after the onset of symptoms. Comparison with dot blot hybridization revealed detectable DNA in only 2/3 PCR positive patients. Thus, nested PCR is more sensitive than the dot blot hybridization method and is therefore a suitable complement to the antibody assay for identifying recent B19 infection.     

Short report: detection of Leishmania DNA by polymerase chain reaction on blood samples from dogs with visceral leishmaniasis.

Immunological, parasitological, and molecular techniques were applied to blood samples of dogs to diagnose Leishmania infections. In 1997, 644 domestic dogs were studied. Peripheral blood samples were collected for serological diagnosis and detection of Leishmania parasite by polymerase chain reaction (PCR). The indirect immunofluorescence test was positive in 139 (21.6%) of 644 dogs examined. The PCR was performed in 70 blood samples and 3 bone marrow aspirates. A 120-bp fragment specific for Leishmania was present in PCR hybridization analysis of all seropositive samples in the molecular assays. The PCR hybridization test, which used a minicircle of Leishmania chagasi as a probe, was negative in 20 seronegative dogs. These results suggest that a combined PCR-Southern hybridization technique is a highly sensitive approach to diagnose leishmaniasis in dogs, which are a zoonotic reservoir of leishmaniasis for humans.     

荧光定量PCR检测嗜吞噬细胞无形体

目的采用新型TaqMan-MGB探针建立检测嗜吞噬细胞无形体的实时荧光定量PCR(quantitativereal-timePCR)方法。方法依据gltA基因序列设计嗜吞噬细胞无形体特异引物和探针,以克隆的嗜吞噬细胞无形体gltA基因片段作DNA模板,在荧光定量PCR检测仪(ABI7900HT)上建立实时荧光定量检测方法。结果建立的定量标准曲线的循环阈值(Ct)与模板拷贝数呈良好的线性关系(r=0.996);与套式PCR相比较,荧光定量PCR检测的灵敏度是其100倍。用荧光定量PCR检测其它相关立克次体和细菌DNA样本,检出结果几乎为0;对荧光定量PCR检测重复性进行分析,变异系数(CV)批内和批间误差在0~2.1%之间,证明该荧光定量PCR具有种特异性和良好的重复性。用荧光定量PCR检测体疑染嗜吞噬细胞无形体的10份蜱和30份小鼠脾脏标本,结果与套式PCR检测结果有密切相关性,但是定量PCR检测敏感性和准确率均高于套式PCR。结论本研究建立的检测嗜吞噬细胞无形体的实时荧光定量PCR具有很高的特异性和敏感性,特别适合检出样本中微量嗜吞噬细胞无形体。     

一种莱姆病螺旋体real-time PCR方法的建立及其在鼠标本检测中的应用评价

目的 基于莱姆病螺旋体recA 基因,建立一种检测鼠中莱姆病螺旋体的real-time PCR方法。方法 通过GenBank分析比较莱姆病螺旋体recA 基因,选择其保守序列设计MGB探针及引物并进行方法学评估。并应用建立的real-time PCR方法和nested PCR方法对收集的123份鼠标本进行检测分析。结果 本研究建立的real-time PCR方法仅对莱姆病螺旋体检测阳性,其最小检出浓度为10¹ copies/μL。标准曲线各浓度点Ct值批内、批间平均变异系数(CV)分别为1.56%和2.30%。123份鼠标本中,real-time PCR检测59例阳性,nested PCR检测43例阳性。结论 新建立的real-time PCR方法具有快速、敏感和特异的优点,可用于鼠标本中莱姆病螺旋体的检测。     

Evaluation of PCR and nested PCR assays currently used for detection of Coxiella burnetii in Japan

Detection of Coxiella burnetii, the etiologic agent of Q fever, is important for diagnosis of Q fever. PCR-based methods have been widely used for the detection mostly because isolation of C. bumetii is time-consuming. Recent reports showed that PCR-positive rates of Q fever infection widely differed. We have evaluated the PCR and nested PCR assays currently used in Japan. The nested PCR assay detected as few as 6 microorganisms and was 10 times more sensitive than the regular PCR assay. The nested PCR assay did not show any non-specific bands with 12 other bacteria, whereas the PCR assay showed some extra bands for 5 of the 12 bacteria. These results suggest that the nested PCR is more sensitive and specific than the PCR in the detection of C. burnetii. However, nested PCR generally has a risk of cross-contamination during preparation of the 2nd PCR. Using blood specimens serially collected from an acute Q fever patient, the PCR and the nested PCR assays gave very similar results, suggesting that sensitivity of the PCR assay is at an achieved level of the detection for clinical specimens although the nested PCR assay is more sensitive. It is recommended that both the PCR and nested PCR assays should be performed for the detection of C. burnetii to obtain reliable results.     

A simple method to detect Plasmodium falciparum directly from blood samples using the polymerase chain reaction.

We have developed a simple method for treating blood samples permitting direct detection of Plasmodium falciparum parasites using the P. falciparum-specific DNA probe pPF14 after polymerase chain reaction (PCR) amplification of target DNA sequences, and have compared this method with microscopic examination of thick blood smears. For PCR amplification, blood samples were lysed, then filtered onto filter paper. After drying, a piece of the filter paper was added directly to the PCR mixture for amplification. The presence of PCR products was detected using nonisotopically labeled probe. This method permits detection of less than than 10 parasites in a 20-microliters sample, and minimizes the effects of PCR inhibitors generally found in blood. Samples were collected from patients presenting at malaria clinics in Mae Sod and Mae Ramat, Thailand, and 626 were analyzed both by the PCR method and by conventional microscopy. Of these, 157 were positive both by microscopy and by PCR, while 297 were negative by both methods. PCR detected 131 samples that were negative by microscopy, and failed to detect 41 samples identified as positive by microscopy. All discordant samples were re-analyzed by microscopy and by PCR. Upon re-examination at a higher sensitivity, microscopy identified five additional positive cases, while six previously positive cases were found to be negative. This method of treating blood samples for PCR may also be useful in other diagnostic assays.     

Use of polymerase chain reaction (PCR) and DNA probe hybridization to determine the Gram reaction of the infecting bacterium in the intraocular fluids of patients with endophthalmitis

OBJECTIVES: To evaluate polymerase chain reaction (PCR) combined with DNA probe hybridization to determine the Gram reaction of the bacterium in intraocular specimens from patients with infectious endophthalmitis. METHODS: Fifty-seven intraocular specimens - 17 aqueous humor (AH) and 40 vitreous fluid (VF) - from 55 patients with clinically diagnosed infectious endophthalmitis and 25 control intraocular specimens from non-infectious ocular disorders (10 AH and 15 VF) were evaluated by microscopy, culture and PCR-DNA probe hybridization to detect the Gram reaction of the bacterium. RESULTS: PCR-DNA probe hybridization was specific and sensitive to detect 30 fg of both gram-positive and gram-negative bacterial DNA. None of the controls showed bacteria by microscopy, culture or PCR. Of the 57 intraocular specimens, conventional microbiological methods could detect a bacterial aetiology in 32 (56.1%), while PCR-DNA probe hybridization could detect 52 (91.2%) specimens. This difference was statistically significant (P= 0.003). In bacteriologically positive specimens, there was absolute correlation of the Gram reaction between the results of smear and culture methods and PCR-DNA probe hybridization. Of the 25 bacteriologically negative specimens, 20 (80%) were positive by PCR-DNA probe hybridization, of which seven (35%) were gram-positive, 12 (60%) gram-negative and one (5%) positive by both. Results of PCR on AH and VF were not significantly different. CONCLUSION: PCR and DNA probe hybridization to determine the Gram reaction of the bacterium in intraocular fluids is a specific and sensitive method in the diagnosis of bacterial endophthalmitis. AH is an ideal specimen for PCR, since its collection is a simple and safe office procedure.