Designing Primers for H5 and H7 Subtypes of Avian Influenza Virus and Multiplex RT-PCR Amplification

[Objective] The research aimed to design primers that are suitable for detecting H5 and H7 subtypes of avian influenza virus （AIV） ; [Method] DNAStar was used to analyze the homology of the sequences of H5 and H7 subtypes of AIV accessed in GenBank, and design primers（ by Primer Premier 5.0） on high homologous region of these sequences, and then amplified by RT-PCR. [Result] The multiplex RT-PCR amplification, agarose gel electrophoresis and sequencing results showed that the self-designed primers are successful for detecting AIV. [Conclusion] It is feasible to rapidly diagnose AIV through this method.

Respiratory Virus Multiplex RT-PCR Assay Sensitivities and Influence Factors in Hospitalized Children with Lower Respiratory Tract Infections

Multiplex RT-PCR assays have been widely used tools for detection and differentiation of a panel of respiratory viral pathogens. In this study, we evaluated the Qiagen ResPlex lI V2.0 kit and explored factors influencing its sensitivity. Nasopharyngeal swab （NPS） specimens were prospectively collected from pediatric inpatients with lower respiratory tract infections at the time of admission in the Shenzhen Children＇s Hospital from May 2009 to April 2010. Total nucleic acids were extracted using the EZ1 system （Qiagen, Germany） and 17 respiratory viruses and genotypes including influenza A virus （FluA）, FluB, parainfluenza virus 1 （PIV1）, PIV2, PIV3, PIV4, respiratory syncytial virus （RSV）, human metapneumovirus （hMPV）, rhinoviruses （RhV）, enteroviruses （EnV）, human bocaviruses （hBoV）, adenoviruses （AdV）, four coronaviruses （229E, OC43, NL63 and HKU1）, and FluA 2009 pandemic H1NI（H1NI-p） were detected and identified by the ResPlex II kit. In parallel, 16 real-time TaqMan quantitative RT-PCR assays were used to quantitatively detect each virus except for RhV. Influenza and parainfluenza viral cultures were also performed. Among the total 438 NPS specimens collected during the study period, one or more viral pathogens were detected in 274 （62.6%） and 201（45.9%） specimens by monoplex TaqMan RT-PCR and multiplex ResPlex, respectively. When results from monoplex PCR or cell culture were used as the reference standard, the multiplex PCR possessed specificities of 92.9-100.0%. The sensitivity of multiplex PCR for PIV3, hMPV, PIV1 and BoV were 73.1%, 70%, 66.7% and 55.6%, respectively, while low sensitivities （11.1%-40.0%） were observed for FluA, EnV, OC43, RSV and H1N1. Among the seven viruses/genotypes detected with higher frequencies, multiplex PCR sensitivities were correlated significantly with viral loads determined by the TaqMan RT-PCR in FluA, H 1N 1-p and RSV （p=0.011-0.000） The Qiagen ResPlex II multiplex RT-PCR kit possesses excellent specificity for simultaneous detection of 17 viral pathogens in NPS specimens in pediatric inpatients at the time of admission. The sensitivity of multiplex RT-PCR was influenced by viral loads, specimen process methods, primer and probe design and amplification condition.

Use of a Multiplex RT-PCR Assay for Simultaneous Detection of the North American Genotype Porcine Reproductive and Respiratory Syndrome Virus,Swine Influenza Virus and Japanese Encephalitis Virus

A multiplex reverse transcriptase-polymerase chain reaction(multiplex RT-PCR) assay was developed and subsequently evaluated for its efficacy in the detection of multiple viral infections simultaneously,in swine.Specific primers for each of the 3 RNA viruses,North American genotype porcine reproductive and respiratory syndrome virus,Japanese encephalitis virus,and swine influenza virus,were used in the testing procedure.The assay was shown to be highly sensitive because it could detect as little as 10-5 ng of each of the respective amplicons in a single sample containing a composite of all 3 viruses.The assay was also effective in detecting one or more of the same viruses in various combinations in specimens,including lymph nodes,lungs,spleens,and tonsils,collected from clinically ill pigs and in spleen specimens collected from aborted pig fetuses.The results from the multiplex RT-PCR were confirmed by virus isolation.The relative efficiency(compared to the efficiency of separate assays for each virus) and apparent sensitivity of the multiplex RT-PCR method show that this method has potential for application in routine molecular diagnostic procedures.

Subtyping Animal Influenza Virus with General Multiplex RT-PCR and Liquichip High Throughput (GMPLex)

This study developed a multiplex RT-PCR integrated with luminex technology to rapidly subtype simultaneously multiple influenza viruses. Primers and probes were designed to amplify NS and M genes of influenza A viruses HA gene of ill, H3, H5, HT, H9 subtypes, and NA gene of the N1 and N2 subtypes. Universal super primers were introduced to establish a multiplex RT-PCR （GM RT-PCR）. It included three stages of RT-PCR amplification, and then the RT-PCR products were further tested by LiquiChip probe, combined to give an influenza virus （IV） rapid high throughput subtyping test, designated as GMPLex. The IV GMPLex rapid high throughput subtyping test presents the following features： high throughput, able to determine the subtypes of 9 target genes in H1, H3, H5, H7, H9, N1, and N2 subtypes of the influenza A virus at one time; rapid, completing the influenza subtyping within 6 hours; high specificity, ensured the specificity of the different subtypes by using two nested degenerate primers and one probe, no cross reaction occurring between the subtypes, no non-specific reactions with other pathogens and high sensitivity. When used separately to detect the product of single GM RT-PCR for single H5 or N1 gene, the GMPLex test showed a sensitivity of 10-5（= 280ELDs0） forboth tests and the Luminex qualitative ratio results were 3.08 and 3.12, respectively. When used to detect the product of GM RT-PCR for H5N1 strain at the same time, both showed a sensitivity of 10-4（=2800 ELD50）. The GMPLex rapid high throughput subtyping test can satisfy the needs of influenza rapid testing.

Rapid Detection Co-infections of Classical Swine Fever Virus and Porcine Reproductive and Respiratory Syndrome Virus by One-step Multiplex RT-PCR

Classical swine fever virus （CSFV） and porcine reproductive and respiratory syndrome virus （PRRSV） have caused immense economic loss in the pig industry and are considered to be the two most important infectious diseases of pigs in the world A multiplex reverse transcription polymerase chain reaction （multiplex RT-PCR） was developed for CSFV and PRRSV co-infections or infections, respectively. A set of two pairs of primer was designed based on the sequence of nonstructural protein NS54B of CSFV and ORF7 gene of PRRSV. The diagnostic accuracy of multiplex RT-PCR assay was evaluated by using 56 field clinical samples by multiplex RT-PCR, single RT-PCR and sequence analysis; and the specificity of multiplex PCR was verified by using constructed plasmids containing the specific viral target fragments of PRRSV and CSFV, respectively. The results indicated that this assay could reliably differentiate PRRSV and CSFV in co-infection samples. The multiplex RT-PCR developed in this study might provide a new avenue to the rapid the detection of CSFV and PRRSV in one reaction.

Detection and Molecular Characterization of Enteroviruses in Korean Surface Water by Using Integrated Cell Culture Multiplex RT-PCR

Objective To identify waterborne enteric viruses in Korean surface water. Methods Integrated cell culture（ICC）multiplex reverse transcription-polymerase chain reaction （RT-PCR） was simultaneously designed to detect coxsackieviruses （CV）, polioviruses （PV）, and reoviruses （RV）. ICC-multiplex RT-PCR and phylogenetic analysis were conducted using 21 total culturable virus assay （TCVA）-positive sample-inoculated cell cultures. Results CV and RV were detected in 9 samples each, and 3 samples were positive for both CV and RV. PV was not detected in any sample. Molecular phylogenetic analysis of the VP1 gene sequences revealed that CV types B2 and B4 predominated in Korean surface water, and the nucleotide sequences of CV type B2 were clustered with those of CVs isolated from China and Japan. The results suggested that the evolution of these viruses occurred in a region-specific manner. Conclusion CV and RV are detectable in Korean surface water, with a predominance of CV type B2, and the evolution of CV type B2 occur in a region-specific manner.

Multiplex RT-PCR-based detections of CEA, CK20 and EGFR in colorectal cancer patients

AIM: To develop a multiplex reverse transcription polymerase chain reaction (RT-PCR) method detecting cir-culating tumor cells in the peripheral blood of colorectal cancer (CRC) patients. METHODS: Peripheral blood samples were collected from 88 CRC patients and 40 healthy individuals from the blood donors' clinic and subsequently analyzed by multiplex RT-RCR for the expression of carcinoembryonic antigen (CEA), cytokeratin 20 (CK20) and epidermal growth factor receptor (EGFR) mRNA. The analysis involved determining the detection rates of CEA, CK20 and EGFR transcripts vs disease stage and overall survival. Median follow-up period was 19 mo (range 8-28 mo). RESULTS: Rates of CEA, CK20 and EGFR detection in CRC patients were 95.5%, 78.4% and 19.3%, respectively. CEA transcripts were detected in 3 healthy volunteer samples (7.5%), whereas all control samples were tested negative for CK20 and EGFR transcripts. The increasing number of positive detections for CEA, CK20 and EGFR transcripts in each blood sample was positively correlated with Astler-Coller disease stage (P< 0.001) and preoperative serum levels of CEA (P=0.029) in CRC patients. Data analysis using Kaplan-Meier estimator documented signif icant differences in the overall survival of the different CRC patient groups as formed according to the increasing number of positivity for CEA, CK20 and EGFR transcripts. CONCLUSION: These data suggest that multiplex RTPCR assay can provide useful information concerning disease stage and overall survival of CRC patients.

Detection of enteroviruses and hepatitis a virus in water by consensus primer multiplex RT-PCR

AIM: To develop a rapid detection method ofenteroviruses and Hepatitis A virus (HAV).METHODS: A one-step, single-tube consensus primersmultiplex RT-PCR was developed to simultaneouslydetect Poliovirus, Coxsackie virus, Echovirus and HAV.A general upstream primer and a HAV primer and fourdifferent sets of primers (5 primers) specific forPoliovirus, Coxsacki evirus, Echovirus and HAV cDNAwere mixed in the PCR mixture to reverse transcriptand amplify the target DNA.Four distinct amplified DNAsegments representing Poliovirus, Coxsackie virus,Echovirus and HAV were identified by gelelectrophoresis as 589-,671-, 1084-, and 1128bpsequences, respectively. Semi-nested PCR was used toconfirm the amplified products for each enterovirus andHAV.RESULTS: All four kinds of viral genome RNA weredetected, and producing four bands which could bedifferentiated by the band size on the gel.To confirmthe specificity of the multiplex PCR products, semi-nested PCR was performed. For all the four strainstested gave positive results .The detection sensitivityof multiplex PCR was similar to that of monoplex RT-PCR which was 24 PFU for Poliovrus, 21 PFU forCoxsackie virus,60 PFU for Echovirus and 105 TCID50for HAV. The minimum amount of enteric viral RNAdetected by semi-nested PCR was equivalent to 2.4 PFUfor Poliovrus, 2.1 PFU for Coxsackie virus, 6.0 PFU forEchovirus and 10.5 TCID50 for HAV.CONCLUSION: The consensus primers multiplex RT-PCRhas more advantages over monoplex RT-PCR for entericviruses detection, namely, the rapid turnaround timeand cost effectiveness.

Detection of the Mex Efflux Pumps in <i>Pseudomonas</i><i>aeruginosa</i>by Using a Combined Resistance-Phenotypic Markers and Multiplex RT-PCR

The aim of this study was to detect the expression of 4 clinically-important efflux pumps in the Resistance-Nodulation-Cell Division (RND) family including MexAB-OprM, MexXY, MexCD-OprJ and MexEF-OprN in Pseudomonas aeruginosa using a combination of resistance-phenotypic markers and multiplex RT-PCR (mRT-PCR). The antibiotic substrates specific for each Mex systems were used as phenotypic markers including carbenicillin, MexAB-OprM, erythromycin, MexCD-OprJ, norfloxacin and imipenem, MexEF-OprN and gentamicin, MexXY-OprM. The methods were validated with reference strains with known genotypes of the Mex systems and the potential applicability in clinical practice was tested with clinical isolates. The results for the reference strains support that the combination of resistance phenotype and mRT-PCR is a potential-attractive method for diagnosis of efflux-mediated resistance in P. aeruginosa. Further development to make it more practical for clinical use and study in a larger number of clinical isolates is required.

Simultaneous detection of duck hepatitis A virus types 1 and 3, and of duck astrovirus type 1, by multiplex RT-PCR

Dear Editor,Duck virus hepatitis(DVH)is caused by at least threedifferent RNA viruses,including duck hepatitis A virus(DHAV),duck astrovirus type 1(DAstV-1),and duckastrovirus type 2(DAstV-2).The first of these,DHAV,has been classified into three serotypes by

Establishment of Multiplex RT-PCR Detection System for Three Viruses in Freesia

The specific primers were designed according to conserved sequences of coat protein （CP） gene of Freesia mosaic virus （FreMV）, Cucumber mosaic vi- rus （CMV） and Bean yellow mosaic virus （BYMV） published in GenBank, and a multiplex PCR protocol for simultaneous detection of these three viruses in freesia was developed. Three specific fragments were simultaneously amplified in a single PCR reaction. Their lengths were determined to be 340,628 and 212 bp, respec-tively. The sequence analysis indicated that three viruses shared at least 97% of homology with reference sequence. Sensitivity test showed that these three viruses could be detected out in the infected plant tissue greater than 10^-2 mg.

蓝舌病新疆分离株VP7蛋白编码基因序列分析及一步法RT-PCR方法的建立

【目的】分析蓝舌病新疆分离株编码VP7蛋白S7基因保守序列,建立蓝舌病新疆分离株一步法RT-PCR方法,为新疆BTV分子流行病学调查及防控提供技术支持。【方法】采用二代测序技术获得新疆分离株S7基因序列,登陆GenBank对序列进行同源性Blast比对,用软件MEGA 5.0分析序列差异,根据蓝舌病新疆分离株编码VP7蛋白S7基因保守序列,运用软件Oligo6.0设计引物,对蓝舌病新疆分离株S7基因进行RT-PCR扩增,并验证该方法的特异性及敏感性。【结果】蓝舌病中国新疆分离株编码VP7蛋白S7基因序列与哈尔滨报道BTV分离株S7基因片段相似度较高为89.64%,与中国云南报道BTV-29型分离株、蒙古国BTV分离株S7基因片段相似度分别为87.49%和87.39%;与德国BTV分离株S7基因片段相似度为80.70%,其余均无同源性序列。中国新疆分离株S7基因片段序列与4条同源序列间存在26处核苷酸差异,9处氨基酸差异。【结论】建立的蓝舌病中国新疆分离株S7基因片段一步法RT-PCR方法具有良好的特异性,仅BTV中国新疆分离株扩增获得目的条带,该方法的敏感性为4.0×10^(3)copies/mL。

河南郑州桃园桃病毒T的RT-PCR检测

通过选取河南省郑州市周边桃园生长不正常的树体叶片,进行RT-PCR检测桃病毒T的感染。结果表明,18份样品中检测到了6份样品存在病毒感染,检出率为33.3%。检出病毒的桃树样品分布在新郑市多个乡镇的果园,共有5个品种检出病毒;来自巩义市的样品未检测出桃病毒T。检出病毒的桃品种既有生产上的老品种,又有近几年栽植的新品种。结合多个桃园的病毒检出,说明病毒T已在生产中存在较长时间,并在局部区域呈扩散趋势。

猪流行性腹泻病毒变异毒株一步法RT-PCR鉴别检测方法的建立及临床应用

为了建立一种快速鉴别检测猪流行性腹泻病毒(PEDV)变异毒株的病原学方法和掌握洛阳市PEDV变异毒株的流行规律,试验根据GenBank中PEDV变异毒株的特异性序列设计引物,通过优化退火温度、模板添加量、引物添加量建立PEDV变异毒株一步法RT-PCR鉴别检测方法,并分析了该方法的特异性、敏感性和重复性;同时应用该方法检测采集自洛阳市的251份临床样品,并对不同地区、不同年份、不同养殖模式的检测结果进行比较分析。结果表明:优化后的退火温度为51℃,模板添加量为5μL,引物添加量为0.5μL;该方法对PEDV变异毒株能够扩增出550 bp特异性条带,而检测的PEDV经典毒株、猪传染性胃肠炎病毒(TGEV)、猪轮状病毒(RV)、猪繁殖与呼吸综合征病毒(PRRSV)、猪瘟病毒(CSFV)、猪细小病毒(PPV)、猪伪狂犬病病毒(PRV)、猪圆环病毒2型(PCV-2)均为阴性;对PEDV变异毒株RNA的最低检测限达到0.74 ng,对3份PEDV变异毒株阳性病料和3份PEDV变异毒株阴性病料重复检测3次的结果完全一致;检测采集于洛阳市251份临床样品的平均阳性率为29.48%,其中不同地区阳性率介于13.33%~44.44%之间,2018—2022年阳性率介于28.30%~31.58%之间,散养户和规模化猪场的阳性率分别为38.24%和19.13%。说明试验建立的PEDV变异毒株一步法RT-PCR鉴别检测方法特异、敏感、稳定、准确,洛阳市PEDV变异毒株的流行特点为个别地区较严重的情况、近几年流行率基本持平、散养户流行情况较规模化猪场严重。

柑橘3种病毒类病原多重RT-PCR检测技术的建立及应用

【目的】建立柑橘黄化脉明病毒(citrus yellow vein clearing virus,CYVCV)、柑橘衰退病毒(citrus tristeza virus,CTV)和啤酒花矮化类病毒(hop stunt viroid,HSVd)的多重RT-PCR检测体系。【方法】设计多重RT-PCR引物,分析其特异性,确定其最佳浓度比、最适退火温度及灵敏度,在此基础上对福建地区的柑橘样品进行检测。【结果】确定了CYVCV-F/R、CTV-F/R和HSVd-F/R等3对引物的最佳浓度比例为1∶1∶2,最适退火温度为52.9℃,灵敏度结果显示该体系可检测模板稀释到10^(-2)的阳性样品。应用该体系对采自福建部分地区的157份柑橘样品进行检测,结果发现,CYVCV、CTV和HSVd的检出率分别为47.1%、56.7%和22.9%。【结论】成功建立了柑橘CYVCV、CTV和HSVd病原的多重RT-PCR检测方法,为该类病害的检测提供准确、快速的检测方法。

猪Linda病毒巢式RT-PCR检测方法的建立

猪Linda病毒能引起仔猪先天性震颤,严重危害养猪业的发展,目前在我国暂未发现感染病例。本研究根据猪Linda病毒Core-E~(ms)基因序列,设计并合成巢式RT-PCR引物,通过对退火温度、引物浓度等进行优化,建立了猪Linda病毒巢式RT-PCR检测方法。结果显示,该方法具有良好的特异性,与非洲猪瘟病毒、猪瘟病毒、猪繁殖与呼吸综合征病毒、猪伪狂犬病病毒、猪圆环病毒2型均无交叉反应;敏感性好,对慢病毒阳性对照品的最低检出限为10~1 copies/μL,比普通RT-PCR灵敏10倍。使用该方法检测模拟病毒样品,发现最低检出限为10~1 TU/mL,与荧光定量RT-PCR方法一致。本研究首次建立了可检测猪Linda病毒的巢式RT-PCR方法,其特异性强、灵敏度高,为在口岸以及条件有限的场地对猪Linda病毒进行精准且快速的检测提供了有效技术手段,也为防范Linda病毒传入提供了有力技术支撑。

帕利亚姆病毒实时荧光定量RT-PCR检测方法的建立与应用

本研究拟建立帕利亚姆病毒(Palyam virus,PALV)血清型特异性实时荧光定量RT-PCR(qRT-PCR)方法用于临床样本或媒介中PALV血清型鉴定。根据我国流行PALV毒株的基因节段2序列,设计扩增引物和TaqMan探针,建立PALV血清型特异型qRT-PCR方法,对方法的特异性、灵敏性与重复性进行评估;以我国分离的28株PALV和90份核酸阳性血液样本评估检测方法的可靠性;利用建立的方法对采集库蠓样本中携带的PALV进行血清型鉴定。结果显示,建立的PALV血清型qRT-PCR检测方法具有良好的特异性与灵敏性,可检出核酸拷贝数下限在22至28 copies·μL^(-1)。对28株PALV的qRT-PCR检测结果与病毒测序鉴定结果一致;对PALV不同感染阶段哨兵动物血液(90份)中的qRT-PCR鉴定结果与分离病毒的血清型鉴定结果一致;建立的方法可准确鉴定库蠓中携带PALV的血清型。本研究建立的PALV血清型qRT-PCR定型方法具有良好的特异强、敏感性与重复性,可用于PALV感染动物与媒介中PALV血清型的鉴定,具有良好的应用价值。

基于RT-PCR方法对河北省桃病毒和类病毒种类的调查鉴定

病毒是造成桃果实产量和品质下降的原因之一,RT-PCR是检测病毒的常用分子生物学方法。利用RT-PCR方法对河北省113份桃样品进行了13种病毒的检测,结果表明,检测到的10种病毒包括ACLSV、PBNSPaV、HSVd、NSPaV、PNRSV、PaLV、PLMVD、APCLSV、PeVD和PPV,其中ACLSV检测率最高,其次是PBNSPaV和HSVd 2种病毒。病毒具有复合侵染的现象,三重侵染和四重侵染的检测率最高,没有检测到不被病毒侵染和单一侵染的样品。研究结果为河北省桃病毒脱除、无病毒苗木繁育奠定了理论基础。

鸽微RNA病毒实时荧光定量RT-PCR检测方法的建立

旨在建立鸽微RNA病毒(pigeon megrivirus,PiMeV)实时荧光定量RT-PCR检测方法。本研究根据GenBank中PiMeVs序列特征设计特异性检测引物,从信鸽粪便中检测到PiMeV阳性(命名为PiMeV-CHN001株),并对其3 C基因进行核苷酸同源性比较和遗传进化分析,明确其基因特征后,设计特异性实时荧光定量RT-PCR检测(RT-qPCR)引物组,建立检测PiMeV的RT-qPCR方法。结果显示:PiMeV-CHN001株3 C基因全长为591 bp,编码197个氨基酸,和其他2株野鸽源PiMeV(MeV-B1株和MeV-B2株)核苷酸相似性分别为89.5%和92.0%。建立的检测PiMeV的RT-qPCR方法的标准曲线Y轴截距为37.93,斜率为-3.335,相关系数为1.00,扩增效率为99.4%。特异性强,仅PiMeV出现特异性扩增信号和特异性峰值[Tm值为(81.69±0.22)℃],对鸽源禽流感病毒(avian influenza virus,AIV)、鸽源禽I型副黏病毒(pigeon paramyxovirus type I,PPMV-1)、鸽输血传播病毒(pigeon torque teno virus,PTTV)、鸽腺病毒(pigeon adenovirus,PiAd)及鸽圆环病毒(pigeon circovirus,PiCV)检测均未见特异性扩增信号;敏感性优,最低检测限为54.0拷贝·μL^(-1);重复性好,批内和批间变异系数均低于1.5%。用建立的检测方法对42份信鸽粪便样品进行检测,发现2份阳性样品(阳性率为4.76%)。本研究首次证实我国大陆地区信鸽中存在PiMeV,丰富了PiMeV宿主谱信息;建立的RT-qPCR方法为后续开展PiMeV流行病学研究提供支撑。

Multi-dimensional multiplexing optical secret sharing framework with cascaded liquid crystal holograms

Secret sharing is a promising technology for information encryption by splitting the secret information into different shares.However,the traditional scheme suffers from information leakage in decryption process since the amount of available information channels is limited.Herein,we propose and demonstrate an optical secret sharing framework based on the multi-dimensional multiplexing liquid crystal(LC)holograms.The LC holograms are used as spatially separated shares to carry secret images.The polarization of the incident light and the distance between different shares are served as secret keys,which can significantly improve the information security and capacity.Besides,the decryption condition is also restricted by the applied external voltage due to the variant diffraction efficiency,which further increases the information security.In implementation,an artificial neural network(ANN)model is developed to carefully design the phase distribution of each LC hologram.With the advantage of high security,high capacity and simple configuration,our optical secret sharing framework has great potentials in optical encryption and dynamic holographic display.