Establishment of a nested-ASP-PCR method to determine the clarithromycin resistance of Helicobacter pylori

AIM: To investigate clarithromycin resistance positions 2142, 2143 and 2144 of the 23 Sr RNA gene in Helicobacter pylori(H. pylori) by nested-allele specific primer-polymerase chain reaction(nested-ASP-PCR).METHODS: The gastric tissue and saliva samples from 99 patients with positive results of the rapid urease test(RUT) were collected. The nested-ASP-PCR method was carried out with the external primers and inner allele-specific primers corresponding to the reference strain and clinical strains. Thirty gastric tissue and saliva samples were tested to determine the sensitivity of nested-ASP-PCR and ASP-PCR methods. Then, clarithromycin resistance was detected for 99 clinical samples by using different methods, including nestedASP-PCR, bacterial culture and disk diffusion. RESULTS: The nested-ASP-PCR method was successfully established to test the resistance mutation points 2142, 2143 and 2144 of the 23 SrR NA gene of H. pylori. Among 30 samples of gastric tissue and saliva, the H. pylori detection rate of nested-ASP-PCR was 90% and 83.33%, while the detection rate of ASP-PCR was just 63% and 56.67%. Especially in the saliva samples, nested-ASP-PCR showed much higher sensitivity in H. pylori detection and resistance mutation rates thanASP-PCR. In the 99 RUT-positive gastric tissue and saliva samples, the H. pylori-positive detection rate by nested-ASP-PCR was 87(87.88%) and 67(67.68%), in which there were 30 wild-type and 57 mutated strains in gastric tissue and 22 wild-type and 45 mutated strains in saliva. Genotype analysis showed that three-points mixed mutations were quite common, but different resistant strains were present in gastric mucosa and saliva. Compared to the high sensitivity shown by nested-ASP-PCR, the positive detection of bacterial culture with gastric tissue samples was 50 cases, in which only 26 drug-resistant strains were found through analyzing minimum inhibitory zone of clarithromycin. CONCLUSION: The nested-ASP-PCR assay showed higher detection sensitivity than ASP-PCR and drug sensitivity testing, which could be performed to evaluate clarithromycin resistance of H. pylori.

Expression of mucosal addressin cell adhesion molecule 1 on vascular endothelium of gastric mucosa in patients with nodular gastritis

AIM: The interaction of mucosal addressin cell adhesion molecule 1 (MAdCAM-1) with integrin α4β7 mediates lymphocyte recruitment into mucosa-associated lymphoid tissue (MALT). Nodular gastritis is characterized by a unique military pattern on endoscopy representing increased numbers of lymphoid follicles with germinal center, strongly associated with H pylori infection. The purpose of this study was to address the implication of the MAdCAM-1/integrin β7 pathway in NG.METHODS: We studied 17 patients with NG and H pylori infection and 19 H pylori-positive and 14 H pylori-negative controls. A biopsy sample was taken from the antrum and snap-frozen for immunohistochemical analysis of MAdCAM1 and integrin β7. In simultaneous viewing of serial sections,the percentage of MAdCAM-1-positive to von Willebrand factor-positive vessels was calculated. We also performed immunostaining with anti-CD20, CD4, CD8 and CD68 antibodies to determine the lymphocyte subsets coexpressing integrin β7.RESULTS: Vascular endothelial MAdCAM-1 expression was more enhanced in gastric mucosa with than without H pylori infection. Of note, the percentages of MAdCAM-1-positive vessels were significantly higher in the lamina propria of NG patients than in H pylori-positive controls. Strong expression of MAdCAM-1 was identified adjacent to lymphoid follicles and dense lymphoid aggregates. Integrin β7-expressing mononuclear cells, mainly composed of CD20 and CD4 lymphocytes, were associated with vessels lined with MAdCAM-1-expressing endothelium.CONCLUSION: Our results suggest that the MAdCAM-1/integrin α4β7 homing system may participate in gastric inflammation in response to H pylori-infection and contributes to MALT formation, typically leading to the development of NG.

广西道地药材肉桂及阴香的DNA分子鉴定研究

建立一种能够准确鉴别肉桂及阴香的特异性聚合酶链式反应方法,以保障肉桂用药的安全性和有效性。通过对比分析肉桂及阴香的psbA-trnH序列差异找到特异性单核苷酸多态性位点,设计特异性引物,通过优化退火温度、循环次数,评估不同聚合酶种类和不同基因扩增仪等扩增条件对不同来源的肉桂及阴香进行特异性扩增,根据特异性扩增条带进行鉴别。结果表明退火温度为54℃,循环次数为35次时,肉桂经肉桂特异性引物扩增后在100~200 bp处出现特异性条带,阴香无条带;退火温度为56℃,循环次数为40次时,阴香经阴香引物扩增后在200~300 bp处出现特异性条带,肉桂无条带。该研究所建立的特异性PCR方法可以快速准确鉴别出肉桂及阴香,为控制肉桂的质量安全提供参考。

马乳酒样乳杆菌马乳酒样亚种real-time PCR检测方法的建立与应用

本研究建立了一种特异性实时聚合酶链式反应(real-time polymerase chain reaction,real-time PCR)检测方法,根据模式菌株马乳酒样乳杆菌马乳酒样亚种ZW3的16S rDNA序列和全基因组序列设计筛选特异性引物,采用SYBR Green I荧光染料建立real-time PCR方法,并对方法的特异性、灵敏度、重复性和混合体系等进行检测。结果表明,本研究所建立的方法特异性强、灵敏度高、重复性好,建立real-time PCR的标准曲线,其决定系数R2为0.965,具有良好的线性关系,且在马乳酒样乳杆菌马乳酒样亚种及混合体系中可以特异性检出。综上,本研究建立的real-time PCR法可以快速、准确地检测马乳酒样乳杆菌马乳酒样亚种,为马乳酒样乳杆菌的特异性定性定量检测提供了一种新的方法。

PCR analysis of Yq microdeletions in infertile males, a study from South India

AIM: To estimate the frequency of microdeletions in the long arm of Y-chromosome of 20 infertile males from South India. METHODS: Polymerase chain reaction (PCR) amplification using Y-specific STS of azoospermia factor (AZF) regions i.e., SY 84 for AZFa, SY 127 for AZFb and SY 254 for AZFc. RESULTS: Of the 20 infertile subjects 3 (15 %), one azoospermic and two oligozoospermic, showed microdeletions in the AZF region of Y-chromosome. CONCLUSION: The frequency of deletions involving AZF region of the Y-chromosome is 15 % in azoospermic and severely oligozoospermic infertile men. PCR amplification of AZF locus is useful for the diagnosis of microdeletions in the Y-chromosome.

Establishment of a molecular tool for blood meal identification in Malaysia

Objective:To establish a polymerase chain reaction(PCR) technique based on cytochrome b {cytb) gene of mitochondria DNA(mtDNA) for blood meal identification.Methods:The PCR technique was established based on published information and validated using blood sample of laboratory animals of which their whole gene sequences are available in CenBank.PCR was next performed to compile gene sequences of different species of wild rodents.The primers used were complementary to the conserved region of the cytb gene of vertebrate's mtDNA.A total of 100 blood samples,both from laboratory animals and wild rodents were collected und analyzed.The obtained unknown sequences were compared with those in the GenBank database using BLAST program to identify the vertebrate animal species.Results:Gene sequences of 11 species of wild animals caught in 9 localities of Peninsular Malaysia were compiled using the established PCR. The animals involved were Rattus(rattus) tanezumi,Rattus tiomanicus,Leopoldamys sabanus, Tupaia glis,Tupaia minor,Niviventor cremoriventor,Rhinosciurus laticaudatus,Calloseiurus caniseps,Sundamys muelleri,Rattus rajah,and Maxomys whitelwadi.The BLAST results confirmed the host with exact or nearly exact matches(>89%identity).Ten new gene sequences have been deposited in CenBank database since September 2010.Conclusions:This study indicates that the PCR direct sequencing system using universal primer sets for vertebrate cytb gene is a promising technique for blood meal identification.

Association of HLA-DRB1, DQB1 Alleles with Chronic Urticaria

In order to investigate the association of genotypes of HLA-DRB1 and HLA-DQB1 alleles with the genetic susceptibility of chronic urticaria (CU), genotypes of HLA-DRB1 and HLA-DQB1 genes were detected by polymerase chain reactions with sequence-specific primers (PCR-SSP) in 42 patients with CU (19 men and 23 women, mean age 30.67±12.45 y old as well as 193 racially matched healthy persons in ethnic Han from Hubei provinece. Gene frequencies of HLA-DRB1*12, *0901 (RR=3.11, χ2=7.579, P=0.006; RR=2.47, χ2=5.684, P=0.017) were significantly increased in CU patients as compared with that in healthy people. Gene frequencies of HLA-DQB1*05 (RR=0.26, χ2=6.683, P=0.01) were significantly decreased in CU patients. It was suggested that CU was found strongly associated with HLA-DRB1*12, *0901 and HLA-DQB1*05, the former might be the genetic markers for susceptibility to CU, but the latter might play a resistive role.

Follow up of infection of chacma baboons with inoculum containing a and non-a genotypes of hepatitis B virus

AIM: To determine whether one genotype (A or non-A genotypes of HBV) predominated over the other during the course of HBV infection.METHODS: Four baboons were inoculated with HBV. DNA was extracted from serum obtained at monthly intervals postinoculation for 52 weeks and HBV DNA was amplified using primers specific for the core region containing an insert characteristic of genotype A (nt 2 354-2 359, numbering from the EcoRI site). The amplicons were cloned into PCRScriptTM and a minimum of 15 clones per time point were sequenced in both directions.RESULTS: Both genotypes persisted for the entire followup period of 52 weeks. Genotype non-A predominated in two baboons and genotype A in one baboon. Neither genotype predominated in the fourth baboon, as shown at a 5 % level of testing.CONCLUSION: No conclusions concerning the dominance of either genotype or the natural progression or replication rates of HBV could be drawn because the pattern of the genotypes found may have been caused by sampling fluctuations at the time of DNA extraction and cloning as a result of the very low viral loads in the baboon sera.

Impact of endoscopically minimal involvement on IL-8 mRNA expression in esophageal mucosa of patients with non-erosive reflux disease

AIM: Little has been known about the pathogenesis of nonerosive reflux disease (NERD). Recent studies have implicated interleukin 8 (IL-8) in the development and progression of gastroesophgeal reflux disease (GERD). The purpose of this study was to determine IL-8 RNA expression levels in NERD patients with or without subtle mucosal changes. METHODS: We studied 26 patients with NERD and 13 asymptomatic controls. Biopsy sample was taken from the esophagus 3 cm above the gast^oesophageal junction and snap frozen for measurement of IL-8 mRNA levels by real-time quantitative polymerase chain reaction (PCR). We also examined mRNA expression of IL-8 receptors, CXCR-1 and -2 by reverse transcriptase PCR. The patients were endoscopically classified into grade M (mucosal color changes without visible mucosal break) and N (neither minimal involvement nor mucosal break) of the modified Los Angeles classification. RESULTS: The relative IL-8 mRNA expression levels were significantly higher in esophageal mucosa of NERD patients than those in esophageal mucosa of the controls. There was a significant difference in IL-8 mRNA levels between grades M and N. The CXCR-1 and -2 mRNAs were consUtutdvely expressed in esophageal mucosa. CONCLUSION: Our results suggest that high IL-8 levels in esophageal mucosa may be involved in the pathogenesis of NERD through interaction with its receptors. NERD seems to be composed of a heterogeneous population in terms of not only endoscopically minimal involvement but also immune and inflammatory processes.

Isolation and Molecular Characterization of <i>Mycoplasma mycoides</i>Subspecie <i>mycoides</i>in 3 Agro Ecological Zones of Nasarawa State, Nigeria

Contagious bovine pleuropneumonia is a disease caused by Mycoplasma mycoides subspecie mycoides, a transboundary animal disease causing serious devastation to cattle producers in Africa. The study was designed to identify and characterize the pathogenic member of mycoplasma cluster the Mycoplasma mycoides subspecie mycoides (Mmm) isolated from cattle infected with the disease. Three hundred (300) samples of nasal swabs and pleural fluid from cattle showing signs of CBPP were analyzed using culture and biochemical identification techniques and polymerase chain reaction (PCR) using specific primers to determine the prevalence of contagious bovine pleuropneumonia in Nasarawa State, Nigeria. Isolation recorded a prevalence of 4% and PCR recorded a prevalence of 67.7%. Isolates subjected to PCR analysis produced an amplicon size of 548 bp and 1.1 k bp respectively for the Mycoplasma mycoides cluster and Mycoplasma mycoides subspecie mycoides. Sequencing of the 16 S rRNA gene blast search revealed 96% to 99% sequence homology of Mycoplasma mycoides subspecie mycoides compared with 14 available sequences in the gen bank at NCBI. Based on this investigation mass vaccination of cattle is recommended, isolation and PCR techniques could be used as diagnostic tools for CBPP disease in three agro ecological zones of Nasarawa state, Nigeria.

温州苍南地区122例畲族MNS血型抗原和基因频率调查

目的:探讨温州苍南地区畲族人群MNS血型系统抗原和基因频率分布情况。方法:收集2021年10月至2022年4月温州医科大学附属苍南医院苍南地区122例畲族人群基本信息及外周血样,采用血清学方法鉴定MNS表现型,荧光聚合酶链反应-序列特异性引物法对MNS基因分型进行检测。结果:温州苍南地区畲族人群的MNS血型血清学定型与基因型结果一致。MNS血型系统的基因频率分别为:M=0.566、N=0.434、S=0.037、s=0.963。基因型MM、MN、NN的频率分别为0.254、0.123、0.623,基因型ss、Ss的频率分别为0.926、0.074,未检测到SS基因型。结论:温州苍南地区畲族人群MNS血型基因频率分布与报道的藏族、汉族其他人群分布相似又有差异,具有自身分布频率特点。

序列特异引物引导的聚合酶链式反应(PCR-SSP)结合血清学在疑难血型鉴定中的应用

目的 探讨血型血清学与序列特异引物引导的聚合酶链式反应(PCR-SSP)基因分型在ABO疑难血型鉴定中的作用。方法 用血清学分析鉴定的ABO疑难血型标本80例,同时采用PCR-SSP法进行基因分型,结合两种方法学结果,确定血型及制定输血策略。结果 血清学鉴定亚型40例,其他原因引起的抗原抗体缺失或减弱正常血型40例;PCR-SSP法基因分型亚型41例(3例二者结果不一致:血清学Ael型1例,基因分型O2O2;血清学O型1例,基因分型BO1;血清学A型1例,基因分型AB),正常血型39例。结论 使用血清学结合基因分型鉴定ABO疑难血型具有重要意义。

一种副干酪乳杆菌快速鉴定方法的建立及应用

目的:基于肠杆菌基因间重复一致序列聚合酶链反应技术(Enterobacterial Repetitive Intergenic Consensus-Polymerase Chain Reaction,ERIC-PCR),寻找并制备一对引物探针,灵敏、准确地从复杂生境中鉴定副干酪乳杆菌。方法:寻找副干酪乳杆菌HP-B1145的肠杆菌基因间重复一致序列(Enterobacterial Repetitive Intergenic Consensus,ERIC)最佳反应体系,对ERIC片段回收纯化得到特定条带及序列结果,据此设计引物,快速鉴定副干酪乳杆菌。结果:根据回收得到的副干酪乳杆菌HP-B1145 ERIC片段,设计出了一对引物探针(1145-S-F:5’-GCAGGATGCTGATTGTTAGCAG-3’;1145-S-R:5’-CTCCGACCAAAGCGACTATGAC-3’)。结论:根据引物特异性、准确性、普适性、含量限度实验得出,设计的引物能准确灵敏地从复杂生境中鉴定副干酪乳杆菌。

中国北方汉族人群HLA-A、HLA-B、HLA-DR等位基因频率检测及其临床意义

目的从基因水平了解中国北方地区汉族人群人类白细胞抗原HLA-A、HLA-B、HLA-DR位点的 等位基因(以下分别简称为A等位基因、B等位基因及DR等位基因)频率,获得更完整、准确的HLA群体遗传学 数据。方法 应用聚合酶链反应一序列特异性引物(PCR-SSP)方法对2000名北方汉族健康志愿者进行A、B、DR 等位基因分型。结果鉴定了17个A等位基因,32个B等位基因,13个DRB1等位基因。最常见的基因型分别 为A*02、B*13、DRB1*15,其相应基因频率范围分别为0.2400-0.2767、0.1330-0.1432和0.1557-0.1707。结 论 本结果可作为我国HLA多态性研究的群体资料和正常参考值,对群体遗传、疾病关联研究以及寻找HLA 相合的异基因造血干细胞供者具有重要意义。

中药材鳖甲的位点特异性PCR鉴定研究

目的 本研究旨在建立一种简便、实用的鳖甲 DNA分子鉴定方法。方法 根据中华鳖和鳖甲混淆品原动物的 12 S r RNA基因片段的序列数据库 ,找出中华鳖与其它鳖科动物有明显区别的位点 ,设计 1对能特异性鉴别中华鳖的引物 ,然后利用鳖甲中残存的 DNA,通过 PCR扩增 ,即可准确鉴别鳖甲。结果 用这对引物对不同来源的10块鳖甲进行鉴定结果表明 ,其中有 3块为伪品 ,结果与 DNA序列分析鉴定一致。还测定了斑鼋和鳖甲一伪品12 S r RNA基因片段序列。结论 该引物配置药材鉴定试剂盒可在鳖甲类药材鉴定使用。

PCR-SSP技术对广东汉族人HLA-DR基因分型

探索具有高分辨率、高特异性和简捷快速的方法对ＨＬＡ－ＤＲ基因分型，为临床器官移植配型和疾病相关性分析提供实用的方法和基础资料．利用ＤＲ１～ＤＲｗ１８序列特异性的１９组引物及１对内参照引物进行ＰＣＲ扩增即ＰＣＲ－ＳＳＰ对ＨＬＡ－ＤＲ进行基因分型，扩增产物经琼脂糖凝胶电泳，溴乙锭染色，在紫外光下观察分型结果．每个被检个体的ＤＲ型别可由特异引物扩增出现的电泳谱带直接判断．双盲检测２２例的结果１００％正确．在１０２例中国广东地区汉族人中，ＤＲ９和ＤＲ２的基因频率最高，分别为０．２２０５和０．１９１２，ＤＲ１０为最低（０．００９８）．与用ＰＣＲ－ＳＳＯ方法分型获得的结果比较，基因型别分布基本一致，但一些等位基因的频率有差异，表明ＨＬＡ－ＤＲ基因频率的分布在不同地区、不同种族的人群间存在着差异．ＰＣＲ－ＳＳＰ法分辨率和特异性虽不及ＰＣＲ－ＳＳＯ法但比血清学方法精细，分型的全过程只需２～４ｈ能满足临床器官移植配型的要求．基因频率调查结果为器官移植配型和疾病相关性分析提供了基础资料．

等位基因特异性引物PCR技术及其应用研究

目的 :研究建立等位基因特异性引物PCR技术体系 ,并将其应用于基因单核苷酸多态性研究工作。方法 :通过美国国家生物信息中心 (NCBI)的genBank获取基因序列及其相应位点的SNP信息。利用Primer5 .0软件设计引物 ,并经NCBI的Blast2 .0软件检验其特异性。结果 :建立了单一等位基因特异性引物PCR(SASP -PCR)与嵌套式等位基因特异性引物PCR(NASP—PCR)两种技术 ,并应用于 β2 肾上腺素受体及内皮源性一氧化氮合酶基因单核苷酸多态性的研究 ,证实该技术的稳定性和优越性。结论 :等位基因特异性引物PCR技术是一种更为简便、特异性较高、费用少的、便于推广的SNP检测方法 。

HLA-DRB1、DQB1基因多态性与流行性出血热的相关性

目的从基因水平探讨HLA-DRB1、DQB1等位基因多态性与流行性出血热的相关性,以阐述其免疫遗传学特征。方法应用序列特异性引物聚合酶链反应技术检测流行性出血热患者和正常对照组各50例的HLA-DRB1、DQB1等位基因。结果流行性出血热患者与正常对照组比较,HLA-DRB1*16等位基因分布频率明显增高(Pc=0.010 6),两组间其余HLA-DRB1-、DQB1等位基因分布频率差异无统计学意义(Pc>0.05)。结论HLA-DRB1*16等位基因与流行性出血热呈正相关,可能为流行性出血热易感基因之一。

PCR-SSP法检测胎儿、新生儿ABO血型

目的 研究用PCR SSP法鉴定胎儿、新生儿血型及基因型。方法 用PCR SSP法检测 5 6例 16周以上孕妇的胎儿、新生儿脐血红细胞基因型 ;用常规法检测双亲及胎儿、新生儿血红细胞ABO血型。结果 用PCR SSP法检测出全部 5 6例脐血ABO血型及基因型 ;PCR SSP法检测出的子代血型与由父母血型按孟德尔遗传规律推测的子代血型符合率达 10 0 % ;用常规法检测脐血ABO血型 ,检出率为 87.5 %。结论 PCR SSP法检测子代ABO血型方法可靠 。

焦磷酸测序中PCR引物与测序引物的设计

利用焦磷酸测序技术进行核酸序列测定时,测序信号过低或非特异性信号过高均会导致测序失败。因此,PCR引物与测序引物的设计十分重要。本研究以rs8175347为例,通过设计具有不同多聚酶亲和指数(PPI)的PCR引物,并运用焦磷酸测序测定其扩增产物,考察了PPI值对扩增效率以及测序信号的影响;以rs914232、rs671位点为例,对比不同测序方向以及dNTP的推注顺序,考察了两者对测序结果的影响。结果表明,提高PCR引物的PPI值有助于增强扩增效率与测序结果的信号峰强度,测序方向和dNTP推注顺序的不合理选择会严重干扰部分SNP测序结果的判断。因此,在设计PCR引物时,应将多聚酶亲和指数理论与传统基于解链温度值的引物设计思路相结合,为焦磷酸测序提供高质量的测序模板;在进行定量测序时,还要综合考虑待测位点(SNP)两侧的序列,选择合适的测序方向以及dNTP的推注顺序,使测序结果更加准确。