PCR鉴定肺炎克雷伯菌的强毒性血清型

目的:了解肺炎克雷伯菌强毒性血清型K1、K2、K54和K57型菌株在我国重庆、北京、深圳三地的分布及流行趋势。方法:采用PCR对310株肺炎克雷伯菌临床分离株进行血清型K1、K2、K54和K57检测。结果:310株菌中,K1、K2、K54和K57血清型分别占14.2%、9.4%、6.5%和4.2%;来自呼吸系统标本分离株中的K1血清型菌株在4种检测的强毒血清型中占首位,为呼吸系统总数的17.4%。结论:310株肺炎克雷伯菌的4种强毒性血清型中,K1血清型菌株所占比例高,较为流行。     

Occurrence and Identification of Eggplant Mottled Crinkle Virus in India

A virus isolated in India from eggplant (Solanum melongena) showing chlorotic rings, line pattern and mosaic on leaves accompanied with stunted growth was identified as a strain of eggplant mottled crinkle virus on the basis of host range, in vitro properties, particle morphology, molecular weight of capsid protein and serological relationship. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis of virus coat protein revealed the presence of a single polypeptide with a molecular weight of 41,000. An antiserum to the virus produced in rabbit had a titre of 1: 2048 in double diffusion tests.     

聚合酶链反应检测实验动物弓形虫核酸的研究

建立弓形虫动物模型,常规方法提取肝、脾、肾、肺等组织DNA,应用聚合酶链反应（PCR）扩增,产物经电泳检测显示199bp的弓形虫特异带谱。并以γ－32p标记克隆的弓形虫特异DNA片段为探针,对扩增产物行Southern印迹分析,结果上述4种标本均出现阳性杂交带,进一步证实扩增条带是弓形虫特异DNA顺序。同时用酶标法检测显示鼠血清弓形虫抗体IgG;阳性。组织病理学检查结果,肝组织损伤较严重,肝细胞肿大,肝窦消失,脾、肾、肺组织可见轻微的病理改变。另外本文介绍一种简单PCR方法[1],取鼠尾静脉血2μl直接进行扩增,结果与酚-氯仿法提取的DNA扩增结果一致。     

Use of Polymerase Chain Reaction to detect Listeria monocytogenes in silages

Polymerase Chain Reaction, based on amplification of a fragment of Dth18 gene, was applied to detect and specifically to identify Listeria monocytogenes present in silages. About 15 CFU g^–1 of fresh or fermented vegetables have been routinely detected using this rapid technique.     

PCR技术在检测鼠金黄色葡萄球菌中的应用研究

目的　建立实验大小鼠金黄色葡萄球菌的快速检测方法———PCR法。方法　根据已公布的金黄色葡萄球菌耐热核酸酶nuc基因的序列 ,设计并合成一对特异性的引物 ,利用PCR技术扩增nuc基因片段。对金黄色葡萄球菌和其他非金黄色葡萄球菌菌株抽提的DNA进行扩增。结果　金黄色葡萄球菌PCR产物出现 6 6 8bp的特异性DNA扩增片段 ,而其他非金黄色葡萄球菌未出现扩增片段 ,证实了合成的引物对金黄色葡萄球菌具有特异性。将抽提的金黄色葡萄球菌DNA进行系列稀释 ,测定此PCR体系的敏感性 ,结果显示 ,该PCR体系能检出 3pg金黄色葡萄球菌DNA ,且从抽提DNA到PCR扩增及电泳结束仅需 4h。结论　本研究所建立的扩增耐热核酸酶nuc基因检测鼠金黄色葡萄球菌的PCR方法 ,具有快速、可靠、敏感和特异的特点 ,可用于临床样品和金黄色葡萄球菌感染时的检测 ,适合应用于实验大小鼠的监测。     

PCR在慢性宫颈炎HSV感染研究中的应用

ＰＣＲ在慢性宫颈炎ＨＳＶ感染研究中的应用蔡红,姚,季晓辉,周瑶玺（南京医科大学微生物学教研室,南京２１００２９）关键词多聚酶链反应,单纯疱疹病毒,宫颈炎单纯疱疹病毒（ＨＳＶ）被认为与宫颈癌有关。目前生殖道ＨＳＶ感染日渐升高,日益引起人们的重视。由于药...     

一步法PCR检测大鼠肺支原体核酸的研究

一步法体外扩增结合Ｓｏｕｔｈｅｒｎ杂交检测Ｍ５３鼠肺支原体标准株,设计一对特异寡核苷酸引物及探针,合成、纯化、建立了特异、敏感、快速的检测手段。扩增产物经琼脂糖凝胶电泳鉴定,结果显示鼠肺支原体Ｍ５３株基因组ＤＮＡ７１０ｂｐ特异谱带。对５０只ＳＤ大鼠进行检测,结果ＰＣＲ方法检出率高于分离培养法,扩增产物行Ｓｏｕｔｈｅｒｎｂｌｏｔ杂交验证,采用碱性磷酸酶标记寡核苷酸探针,可与膜上特异靶ＤＮＡ序列杂交,而阴性对照无杂交信号。特异性实验检出１０ｐｇ的ＤＮＡ。充分说明一步法ＰＣＲ,具有高度、特异、灵敏、快速等优势,适应与大、小鼠监测中应用。     

Use of Polymerase Chain Reaction for the Detection of Infectious Hypodermal and Hematopoietic Necrosis Virus in Penaeid Shrimp

A rapid and reliable polymerase chain reaction (PCR) method was developed for the detection of infectious hypodermal and hematopoietic necrosis virus (IHHNV) in penaeid shrimp. The oligonucleotide primers amplify a 1681-bp fragment of IHHNV, which encompasses the coding sequence for one of the viral coat proteins. The PCR method detects IHHNV in hemolymph and homogenized tissue obtained from the cephalothorax or pleopods of infected shrimp. The technique was also successfully applied to tissue samples preserved in 70% ethanol. The correct size fragment was amplified using IHHNV obtained from six different geographic regions in three different species of penaeid shrimp. No DNA extraction method was necessary for this technique. The use of hemolymph or pleopods provides a nondestructive screening method by which to test juveniles and adult broodstock for the presence of IHHNV. Received September 21, 1999; accepted January 21, 2000     

四种广普性植物病毒高效mPCR检测方法的建立

本研究建立了能同时检测出烟草花叶病毒(TMV)、黄瓜花叶病毒(CMV)、马铃薯X病毒(PVX)和马铃薯Y病毒(PVY)的多重RT-PCR体系。TMV、CMV、PVX、PVY是四种广普性植物病毒,寄主范围广泛,并且常常发生复合侵染。本研究以上述四种病毒的CP基因部分序列设计引物,以反转录的cDNA为模板,建立多重RT-PCR反应体系,分别扩增出211～417bp的不同长度的基因片断,并通过序列测定来确认扩增序列的特异性。将反转录合成的cDNA进行浓度稀释,来对多重RT-PCR与单重RT-PCR的灵敏度进行比较,结果证明,多重RT-PCR体系能够同时快速检测这四种病毒,并且有很高的灵敏度。     

定量PCR的荧光技术

荧光定量PCR是在普通PCR基础上,利用荧光技术对核酸进行绝对定量的一项新兴技术,其灵敏度高、特异性高、操作简便和定量准确,已被广泛应用于临床和科研中。为更好地发挥荧光定量PCR的优点,荧光技术领域的研发工作十分活跃。     

A Fast-and-Robust Profiler for Improving Polymerase Chain Reaction Diagnostics

Polymerase chain reaction (PCR) is an in vitro technology in molecular genetics that progressively amplifies minimal copies of short DNA sequences in a fast and inexpensive manner. However, PCR performance is sensitive to suboptimal processing conditions. Compromised PCR conditions lead to artifacts and bias that downgrade the discriminatory power and reproducibility of the results. Promising attempts to resolve the PCR performance optimization issue have been guided by quality improvement tactics adopted in the past for industrial trials. Thus, orthogonal arrays (OAs) have been employed to program quick-and-easy structured experiments. Profiling of influences facilitates the quantification of effects that may counteract the detectability of amplified DNA fragments. Nevertheless, the attractive feature of reducing greatly the amount of work and expenditures by planning trials with saturated-unreplicated OA schemes is known to be relinquished in the subsequent analysis phase. This is because of an inherent incompatibility of ordinary multi-factorial comparison techniques to convert small yet dense datasets. Treating unreplicated-saturated data with either the analysis of variance (ANOVA) or regression models destroys the information extraction process. Both of those mentioned approaches are rendered blind to error since the examined effects absorb all available degrees of freedom. Therefore, in lack of approximating an experimental uncertainty, any outcome interpretation is rendered subjective. We propose a profiling method that permits the non-linear maximization of amplicon resolution by eliminating the necessity for direct error estimation. Our approach is distribution-free, calibration-free, simulation-free and sparsity-free with well-known power properties. It is also user-friendly by promoting rudimentary analytics. Testing our method on published amplicon count data, we found that the preponderant effect is the concentration of MgCl₂ (p<0.05) followed by the primer content (p<0.1) whilst the effects due to either the content of the deoxynucleotide (dNTP) or DNA remained dormant (p>0.1). Comparison of the proposed method with other stochastic approaches is also discussed. Our technique is expected to have extensive applications in genetics and biotechnology where there is a demand for cheap, expedient, and robust information.     

Micro-droplet Digital Polymerase Chain Reaction and Real-Time Quantitative Polymerase Chain Reaction Technologies Provide Highly Sensitive and Accurate Detection of Zika Virus

The establishment of highly sensitive diagnostic methods is critical in the early diagnosis and control of Zika virus(ZIKV)and in preventing serious neurological complications of ZIKV infection. In this study, we established micro-droplet digital polymerase chain reaction(ddPCR) and real-time quantitative PCR(RT-qPCR) protocols for the detection of ZIKV based on the amplification of the NS5 gene. For the ZIKV standard plasmid, the RT-qPCR results showed that the cycle threshold(Ct) value was linear from 10~1 to 10~8 copy/l L, with a standard curve R~2 of 0.999 and amplification efficiency of 92.203%;however, a concentration as low as 1 copy/l L could not be detected. In comparison with RT-qPCR, the dd PCR method resulted in a linear range of 10~1–10~4 copy/l L and was able to detect concentrations as low as 1 copy/l L. Thus, for detecting ZIKV from clinical samples, RT-qPCR is a better choice for high-concentration samples(above 10~1 copy/l L),while ddPCR has excellent accuracy and sensitivity for low-concentration samples. These results indicate that the ddPCR method should be of considerable use in the early diagnosis, laboratory study, and monitoring of ZIKV.     

Differentiation of Chlamydia Species by Combined Use of Polymerase Chain Reaction and Restriction Endonuclease Analysis

To differentiate Chlamydia spp., a primer pair designed to generate a genus-specific region of the major outer membrane protein (MOMP) gene was used in a PCR to amplify a single DNA fragment of 245-259 bp. In the PCR, the expected single DNA fragment was amplified from strains of Chlamydia trachomatis, C. psittaci, C. pneumoniae and C. pecorum, respectively. By restriction endonuclease analysis with AluI and PvuII, the amplified products exhibited four distinct patterns, corresponding to the four species. It is, therefore, concluded that one-step PCR followed by restriction endonuclease analysis as described in this study could be a valuable method for the detection and differentiation of Chlamydia species.     

Multivariate Optimization of Polymerase Chain Reaction for Microbial Community Analysis

A multivariate regression, partial least square (PLS) approach was used to optimize a polymerase chain reaction (PCR) method for mixed communities. This approach, in contrast to univariate ones, provided information on the relative influence of the different factors to be optimized, as well as the interactions between factors. Models that predicted the outcome of further optimization were constructed from the initial experiments and verified experimentally. The models constructed were able to predict the outcome of a second set of experiments with high accuracy. PCR-amplification of DNA from environmental samples is often the first step in microbial community fingerprinting. Inhibitors and low cell numbers in the samples can cause problems with yield, for which compensation is normally made by increasing the number of cycles in the PCR-amplification reaction. Increasing the number of cycles, however, can cause other problems such as heteroduplex formation and increased bias. To avoid these problems the effects of different times of denaturing, annealing, and extension on yield were investigated for 2 different samples, one that consisted of a mixture of 9 laboratory strains, and one that represented the microbial community from the surface of the red alga Delisea pulchra. The multivariate approach showed, in addition to the successful optimization of yield, that the different factors affected the PCR depending on sample type. Annealing time had the largest effect on yield for the mixture of laboratory strains, whereas extension time was most important for the D. pulchra community. We suggest that multivariate optimization is a useful tool for PCR optimization and can be used irrespectively of the particular factors that are being investigated.