Development of a multiplex polymerase chain reaction assay for detection of hepatitis C virus,hepatitis B virus,and human immunodeficiency virus 1

BACKGROUND Hepatitis C virus(HCV),hepatitis B virus(HBV),and human immunodeficiency virus 1(HIV-1)are the most epidemic blood-borne viruses,posing threats to human health and causing economic losses to nations for combating the infection transmission.The diagnostic methodologies that depend on the detection of viral nucleic acids are much more expensive,but they are more accurate than sero-logical testing.AIM To develop a rapid,cost-effective,and accurate diagnostic multiplex polymerase chain reaction(PCR)assay for simultaneous detection of HCV,HBV,and HIV-1.METHODS The design of the proposed PCR assay targets the amplification of a short conserved region featured with a distinguishable melting profile and electro-phoretic molecular weight inside each viral genome.Therefore,this diagnostic method will be appropriate for application in both conventional(combined with electrophoresis)and real-time PCR facilities.Confirmatory in silico investigations were conducted to prove the capability of the approached PCR assay to detect variants of each virus.Then,Egyptian isolates of each virus were subjected to the wet lab examination using the given diagnostic assay.RESULTS The in silico investigations confirmed that the PCR primers can match many viral variants in a multiplex PCR assay.The wet lab experiment proved the efficiency of the assay in distinguishing each viral type through high-resolution melting analysis.Compared to related published assays,the proposed assay in the current study is more sensitive and competitive with many expensive PCR assays.CONCLUSION This study provides a simple,cost-effective,and sensitive diagnostic PCR assay facilitating the detection of the most epidemic blood-borne viruses;this makes the proposed assay promising to be substitutive for the mistakable and cheap serological-based assays.

Efficacy of stool multiplex polymerase chain reaction assay in adult patients with acute infectious diarrhea

BACKGROUND Recently,stool multiplex polymerase chain reaction(PCR)tests have been developed for identifying diarrhea-causing bacterial pathogens.Furthermore,fecal calprotectin is a well-known effective marker for intestinal mucosal inflammation.AIM To evaluate the efficacy of stool multiplex PCR and fecal calprotectin in acute infectious diarrhea.METHODS Overall,400 patients with acute infectious diarrhea were enrolled from Kangdong Sacred Heart Hospital(January 2016 to December 2018).Multiplex PCR detected 7 enteropathogenic bacteria including Salmonella,Campylobacter,Shigella,Escherichia coli O157:H7,Aeromonas,Vibrio,and Clostridium difficile.We reviewed clinical and laboratory findings using stool multiplex PCR.RESULTS Stool multiplex PCR test detected considerably more bacterial pathogens than stool culture(49.2%vs 5.2%),with Campylobacter as the most common pathogen(54%).Patients with positive stool PCR showed elevated fecal calprotectin expression compared to patients with negative stool PCR(1124.5±816.9 mg/kg vs 609±713.2 mg/kg,P=0.001).C-reactive protein(OR=1.01,95%CI:1.001-1.027,P=0.034)and sigmoidoscopy-detected colitis(OR=4.76,95%CI:1.101-20.551,P=0.037)were independent factors in stool PCR-based detection of bacterial pathogens.Sensitivity and specificity of calprotectin were evaluated to be 70.5%and 60.9%,respectively(adjusted cut-off value=388 mg/kg).CONCLUSION Stool multiplex PCR test has increased sensitivity in detecting pathogens than conventional culture,and it is correlated with calprotectin expression.Stool multiplex PCR and calprotectin may be effective in predicting clinical severity of infectious diarrhea.

Establishment of a Multiplex PCR System to Diagnose Tuberculosis and Other Bacterial Infections

In order to rapidly diagnose and differentiate tuberculosis from other bacterial infections, a 16S rRNA gene (16s rDNA)-directed multiplex PCR system was developed. In this system, a pair of universal primers and a tubercle bacillus (Tb)-specific primer were designed based on highly con- served regions and Tb species-specific variable region of bacterial 16s rDNA. A 360bp fragment was detected in all bacteria tested, and a 210bp fragment was found only in Tb. 19 species of known bac- teria including Tb were used for evaluating specificity, universality and sensitivity of the PCR. Candi- da albicans and human diploid cell served as controls. It was found that both 210bp and 360bp frag- ments were amplified only in Tb, and only 360 bp fragment was detected in other 18 species of gener- al bacteria. Candida albicans and human cells were negative for both 360bp and 2l0bp fragments. The lowest detectable level of the PCR was 10 fg of DNA for Escherichia coli and 100 fg of DNA for Tb. The results indicated that this multiplex PCR system for the simultaneous detection of Tb and other common bacteria had higher specificity and sensitivity, as well as good universality and might be useful to rapidly diagnose bacterial infections and effectively distinguish tuberculosis from other bacterial involvement.

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.

马铃薯SSR标记多重PCR反应体系优化研究

以马铃薯品种克新18为试验材料,探讨了多重PCR反应体系主要成分、引物不同比例关系及退火温度对SSR标记扩增的影响。在不改变其他成分浓度的条件下,对PCR反应体系的4个组分(Taq酶、MgCl2、模板DNA、dNTPs)进行浓度或用量梯度试验;利用正交设计L(934)对反应体系的4对引物组合(STM0014、Pat、SSI、UGP)在3个水平上进行优化;最终确立了马铃薯SSR标记多重PCR反应优化体系,总体积为20μL;2.5μL 25 mmol.L-1 MgCl2,0.6μL 10 mmol.L-1 dNTPs,Taq酶0.8 U,模板DNA 80 ng;4 mmol.L-1的4对引物之间的用量比为2:1:2:3,退火温度为54.7℃。优化后的反应体系重复性好,扩增结果稳定可靠,能够明显区分不同的马铃薯品种。为进一步探讨马铃薯品种资源遗传多样性、构建DNA指纹图谱打下了坚实的基础。

食源性致病菌通用型多重荧光PCR快速检测体系的建立

以两种食源性致病菌(沙门氏菌、单增李斯特菌)为模板,对通用型多重荧光PCR快速检测体系进行了研究。建立的通用型多重荧光PCR反应体系为:25μL反应液中,Tris-HCl为50mmol/L、pH值为8.8、KCl15mmol/L、(NH4)2SO4为8mmol/L、Mg2+为3mmol/L、dNTP为1.0mmol/L、引物和探针的终浓度分别为1μmol/L和0.5μmol/L、加入0.5μLDMSO,2.5U/份的Taq酶与等量的Taq酶抗体。

山东汉族RhD阴性个体基因多态性研究

目的研究山东汉族人群RhD阴性个体RhD基因多态性。方法采用标准血清学方法和抗球蛋白实验筛选Rh阴性个体;对Rh阴性个体再用吸收放散实验确定DEL型。运用多重聚合酶链反应(PCR)方法分析RhD阴性个体基因存在情况。结果67例Rh阴性个体中DEL型16例,占Rh阴性个体的23.88%,其6个RhD基因特异性的第3、4、5、6、7、9外显子全部存在;剩下51例Rh阴性个体中1例缺失第5外显子,其余50例6个外显子全部缺失。结论山东汉族人群RhD阴性个体中存在一定比例的DEL型,且所有DEL样本均具有完整的RhD基因,在排除DEL型后的RhD阴性个体可能携带RhD基因,但其比例较低。

Prevalent false positives of azoospermia factor a （AZFa） microdeletions caused by single-nucleotide polymorphism rs72609647 in the sY84 screening of male infertility

Multiplex polymerase chain reaction （PCR） has been widely used to detect Y-chromosome micredeletions, which is one of the major causes of male infertility. Both the European Academy of Andrology （EAA） and the European Molecular Genetics Quality Network （EMQN） have recommended the use of sY84 and sY86 markers for the detection of azoospermia factor a （AZFa） microdeletion during DNA testing for male infertility. In this study, a large-scale analysis of AZF microdeletion in a total of 630 Chinese males, including healthy semen donors （n=200）, infertile males with normal sperm count （n=226） and patients with either nonobstructive azoospermia or severe oligozoospermia （n=204）, was performed. A series of nine sequence-tagged site （STS） markers from the AZF region of the Y chromosome was used to detect microdeletions. All primers were designed based on the recommendations of the National Center for Biotechnology Information. An unusually high incidence （73/630, 11.6%） of sY84-absent but sY86-present genotypes was observed in the AZFa microdeletion screening. Sequencing the sY84-flanking region revealed a total of 73 patients with sY84-absent but sY86-present genotypes have a T-to-G transversion at the fifth base from the 5＇ end of the reverse sY84 primer. These prevalent false positives, which were not only observed in infertile men, but also observed in donors, resulted from a single-nucleotide polymorphism （SNP） named rs72609647 in the targeting sequence of the reverse sY84 primer. Our study suggests that a pre-screening of existence of rs72609647 polymorphism can prevent the frequent false positive results of AZFa microdeletions detection in the infertile Chinese males. Given the SNP rs72609647 was recently found in a deep sequencing of a Chinese individual, the current EAA and EMQN standards may need to be scrutinized among different populations to avoid the potential genetic variations in the primer binding sequences.

Molecular study on Y chromosome microdeletions in Egyptian males with idiopathic infertility

Aim: To determine the frequency of genetic deletions within the azoospermia factors in Egyptian infertile males. Methods: The Yq microdeletions in 33 infertile males with undetectable chromosomal anomalies were examined by mutiplex polymerase chain reaction (PCR). Deletions were confirmed using single PCR amplifications. Results: Four out of the total 33 (12 %) men had Yq11 microdeletions, thus supporting the average reported figures in other populations. Three of those 4 cases had single short tandem sequence deletions with discrete histological findings of their testes. Single sY272 deletion within AZFc was associated with Sertoli cell only syndrome, whereas a patient with isolated sY84 deletion within AZFa had immature testicular structure. The remaining case had a large deletion in AZFa-c and short stature. Conclusion: The present study supports the hypothesis that the Yqn encompasses genetic determinants of stature besides genes controlling spermatogenesis.

Combination of Cytogenetic Analysis and Molecular Screening in Patients with de novo Acute Myeloid Leukemia

Nowadays the role of genetic findings in determining the diagnosis,therapy and prognosis of acute myeloid leukemia(AML) has become more valuable.To improve and validate the detection of clonal chromosomal aberrations in leukemia,we designed a combined application of karyotyping with multiplex reverse transcription-polymerase chain reaction(RT-PCR) and fluorescence in situ hybridization(FISH),and addressed the expression and distribution of fusion genes among the subtypes of Chinese adult patients with de novo AML.Multiplex RT-PCR assays were performed on 477 samples from newly diagnosed AML patients,and cytogenetic data were obtained from 373 of them by R or G banding techniques and those in some cases were confirmed by FISH.The PCR products in some suspected cases were tested by two-directional sequencing.The results showed that except unqualified samples,fusion genes were detected by multiplex RT-PCR in 211 of 474 patients(44.51%),including AML1-ETO,CBFβ-MYH11,PML-RARα,PLZF-RARα,NPM-RARα,MLL rearrangements,BCR-ABL,DEK-CAN,SET-CAN,TEL-PDGFR,TLS-ERG,AML1-MDS1(EVI-1).In 373 patients,who took both multiplex RT-PCR and karyotype analysis,the detection rate of chromosomal aberrations by using multiplex RT-PCR and karyotyping was 160/373(42.89%) and 179/373(47.98%) respectively,and the combination could optimize the detection rate of clonal genetic abnormalities to 216/373(57.90%).The PCR results from 11 cases 'normal' in karyotyping but abnormal in RT-PCR for MLL rearrangements were confirmed by two-directional sequencing.It is concluded that karyotype studies remain the cornerstone for genetic testing;conventional cytogenetics and molecular-based methods are complementary tests for the detection of clonal genetic aberrations in AML,especially for the cryptic or submicroscopic aberrations.Once a genetic marker has been identified by combined analysis,it could be used to monitor residual disease during/after chemotherapy,by quantitative RT-PCR and/or FISH.

Rapid prenatal diagnosis of trisomy 21 by fluorescent quantitative multiplex polymerase chain reaction

Trisomy 21, also named Down syndrome was the most frequent autosomal aneuploidy and the most common cause of mental retardation. Fifty percent patients had congenital heart malformation. Every 20 minutes one case of trisomy 21 was born, and the incidence rate was 1 in 600 to 800 newborns in China.1 In two thirds of cases with trisomy 21, there was a spontaneous abortion, so the actual incidence was higher than that obtained postnatally.

Forensic Identification of Four Indian Snake Species Using Single Multiplex Polymerase Chain Reaction

Among different endangered animal species,snakes are the most neglected creature looked at with apathy and therefore,are ruthlessly killed,illegally trafficked,and poached for their venom,lucrative skin,meat,and bones for manufacturing of medicines,accessories,and food items.Establishing the identity of the endangered snake species is important for punishing the offenders under Wildlife Protection Act(WPA)(1972)but morphological characters fail to establish identity as they are often altered.The technique of identification of snake species at molecular level holds very effective conclusion in punishing offender.Here,we have constructed and demonstrated a novel multiplexing polymerase chain reaction technique,using 16S rRNA and C-mos gene for identification of four Indian snake species,namely Ptyas mucosa,Daboia russellii,Naja naja,and Xenochrophis piscator.They are listed in Appendix-II and III of convention on international trade in endangered species of wild fauna and flora and Schedule II;Part II of Indian WPA,1972.Therefore,it may be considered a functional tool for establishing species-specific identity of four Indian snake species and promising to be useful for their conservation.

T-ARMS PCR多重检测方法研究

目的 建立有错配的加尾双引物扩增受阻突变体系聚合酶链反应(T-ARMS PCR)多重检测的方法,实现针对肝细胞癌常见基因突变位点TP53 R249S、TP53 R273H、CTNNB1 S45F的多重检测。方法 针对3个基因突变位点进行引物设计,每个基因突变位点所设计引物序列的5′端不加一段DNA序列(Tail Free Primer)或者所设计的引物序列5′端加一段相同的DNA序列(Tailed Primer),利用实时荧光定量PCR仪分别检测并比较3个基因突变位点的不同引物序列形成的单重体系、三重体系的扩增结果,研究T-AMRS PCR方法对突变型基因位点突变负荷的检测限、特异性和多靶标检测能力。结果 3个基因突变位点Tailed Primer单重体系扩增结果显示,突变型质粒的扩增均优于野生型质粒,野生型质粒的扩增均被有效抑制,突变负荷检测限低至0.10%,特异性良好。Tailed Primer三重体系减少了引物二聚体的产生,调控CTNNB1 S45F、TP53 R249S、TP53 R273H的解链温度分别为81.11℃、82.36℃、86.35℃,实现不同突变位点的显著区分。与Taqman探针基因分型方法相比,T-AMRS PCR方法野生型和突变型基因的Ct值差异更显著,单荧光通道即可实现突变基因检测。结论 运用T-ARMS PCR进行一管三重检测,分析熔解曲线,能有效检测到目的基因突变,抑制野生型模板的扩增,并区分不同的基因突变位点;同时,Tailed Primer设计减少了多重情况下引物二聚体的产生。该方法可为临床中肝细胞癌的早期筛查、预后预测、病情监测提供理论依据。

适于玉米杂交种复杂样品纯度鉴定的SSR复合检测方案的建立

为了解决玉米复杂样品纯度中存在遗传不稳定及回交株等难以鉴定的问题,通过分析3998份国家和省级审定玉米品种,结合快速提取、多重扩增体系等技术,构建一套适用于复杂样品纯度检测的复合检测方案。分析53份不同来源的郑单958纯度测试样品,结果表明,对于复杂样品使用单个位点进行纯度判定时,不同位点间结果会有较大差别,使用3个或3个以上位点综合判定时能够有效获得准确稳定的纯度检测结果。复合检测方案能够在时间和成本未大幅增加、仅增加少数引物的条件下获得多个SSR标记指纹,使复杂样品得到更加全面、精准解析,从而为种子生产中复杂样品的质量问题提供解决方案。

Developmental Validation of the EX16+22Y System

The EX 16+22Y system is a polymerase chain reaction(PCR)-based amplification kit that enables typing of 15 autosomal short tandem repeat(STR)loci(i.e„D3S1358,D13S317,D7S820,D16S539,TPOX,TH01,D2S133&CSF1PO,D19S433,vWA,D18S51,D21S11,D8S1179,D5S81&and FGA)and 22 widely used Y chromosome STR(Y-STR)loci(DYS391,DYS527a/b,DYS635,DYS458,DYS456,DYS385a/b,DYS43&DYS44&DYS437,DYS19,DYS576,DYS533,DYS393,DYS389I/n,DYS439,DYS392,Y_GATA_H4,DYS390,and DYS481)which contains 20 core Y-STR recommended by the Ministry of Public Security and amelogenin.This multiplex system was designed for the simultaneous analysis of amelogenin-Y allele mutation,single-source searches,kinship(including familial searching),mixture profiles,international data sharing,and other forensic applications.In this study,the multiplex system was validated for sensitivity of detection,species specificity,DNA mixtures,stability,sizing precision,stutter,reproducibility,and PCR-based conditions according to the Scientific Working Group on DNA Analysis Methods developmental validation guidelines and Chinese criteria for the human fluorescent STR multiplex PCR reagent.The results show that the EX16+22Y system is a robust and reliable amplification kit which can be used for human identification testing.

多重聚合酶链反应系统用于儿童常见细菌及真菌血流感染的价值研究

目的探讨多重聚合酶链反应系统用于儿童常见细菌及真菌血流感染的价值。方法选取2014年1月-2016年1月医院住院疑诊血流感染患儿135例,采集患儿的血标本,分别采用血培养法、16SrDNA-PCR和多重聚合酶链反应系统进行检测,对比3种方法检测儿童血流感染的阳性率。结果血培养法检测阳性标本12份,阳性率为8.89%,16SrDNA-PCR检测阳性标本26份,阳性率为19.26%,多重聚合酶链反应系统检测阳性标本24份,阳性率为17.78%;16SrDNA-PCR和多重聚合酶链反应系统的阳性率均显著高于血培养法(P<0.05);16SrDNA-PCR和多重聚合酶链反应系统阳性率比较,差异无统计学意义。结论多重聚合酶链反应系统具有操作简单、检测时间短等优势,可在较短时间内鉴定儿童血流感染的常见病原菌,对临床诊疗有较好的指导意义。

基于微卫星标志构建湖北钉螺PCR多重反应体系

目的筛选湖北钉螺多态性微卫星位点,建立多重反应体系,以对钉螺进行基因分型和群体遗传学分析。方法从GenBank数据库和文献中筛选合适的湖北钉螺微卫星位点,设计合成引物并进行评价,构建多重反应体系。结果从GenBank中获得4个满足条件的三核苷酸重复序列位点,从文献中获得9个双核苷酸序列位点;成功设计合成11对引物,其中5对引物扩增效果好。最终构建的多重反应体系中5个位点均具有高度多态性,且不存在连锁不平衡。结论研究所建立的多重反应体系扩增效果好、各位点多态性高,将有利于后续开展针对钉螺扩散的溯源研究。

Screening for Y chromosome microdeletions in idiopathic and nonidiopathic infertile men with varicocele and cryptorchidism

Cytogenetic and molecular studies of azoospermic and oligozoospermic males have suggested the presence of azoospermia factors （AZF） in the Y chromosome. Deletion in AZF regions has been reported to disrupt spermatogenesis and cause infertility. Several candidate genes responsible for spermatogenesis have been identified in this region and some of them are thought to be functional in human spermatogenesis. And we reported clinical and molecular studies of Y chromosome microdeletions in Chinese. This study aimed at assessing the frequency of microdeletions in Chinese men with idiopathic and nonidiopathic infertility problems and dicussing the clinical significance of the AZF region.

Molecular Analysis-Based Genetic Characterization of a Cohort of Patients with Duchenne and Becker Muscular Dystrophy in Eastern China

Background： Duchenne muscular dystrophy （DMD） and Becker muscular dystrophy （BMD） are common X-linked recessive neuromuscular disorders caused by mutations in dystrophin gene. Multiplex polymerase chain reaction （multiplex PCR） and multiplex ligation-dependent probe amplification （MLPA） are the most common methods for detecting dystrophin gene mutations, This study aimed to contrast the two methods and discern the genetic characterization of patients with DMD/BMD in Eastern China. Methods： We collected 121 probands, 64 mothers ofprobands, and 15 fetuses in our study. The dystrophin gene was detected by multiplex PCR primarily in 28 probands, and MLPA was used in multiplex PCR-negative cases subsequently. The dystrophin gene of the remaining 93 probands and 62 female potential carriers was tested by MLPA directly. In fetuses, multiplex PCR and MLPA were performed on 4 fetuses and 10 fetuses, respectively. In addition, sequencing was also performed in 4 probands with negative MLPA. Results： We found that 61.98% of the subjects had genetic mutations including deletions （50.41%） and duplications （11.57%）. There were 43.75% of mothers as carriers of the mutation. In 15 fetuses, 2 out of 7 male fetuses were found to be unhealthy and 2 out of 8 female fetuses were found to be carriers. Exons 3-26 and 45-52 have the maximum frequency in mutation regions. In the frequency ofexons individually, exon 47 and exon 50 were the most common in deleted regions and exons 5, 6, and 7 were found most frequently in duplicated regions. Conclusions： MLPA has better productivity and sensitivity than multiplex PCR. Prenatal diagnosis should be applied in DM D high-risk fetuses to reduce the disease incidence. Furthermore, it is the responsibility of physicians to inform female carriers the importance of prenatal diagnosis.