Rapid Detection of Rifampin-resistant Clinical Isolates of Mycobacterium tuberculosis by Reverse Dot Blot Hybridization

Objective A PCR-reverse dot blot hybridization(RDBH) assay was developed for rapid detection of rpo B gene mutations in ‘hot mutation region' of Mycobacterium tuberculosis(M. tuberculosis). Methods 12 oligonucleotide probes based on the wild-type and mutant genotype rpoB sequences of M. tuberculosis were designed to screen the most frequent wild-type and mutant genotypes for diagnosing RIF resistance. 300 M. tuberculosis clinical isolates were detected by RDBH, conventional drug-susceptibility testing(DST) and DNA sequencing to evaluate the RDBH assay. Results The sensitivity and specificity of the RDBH assay were 91.2%(165/181) and 98.3%(117/119), respectively, as compared to DST. When compared with DNA sequencing, the accuracy, positive predictive value(PPV) and negative predictive value(NPV) of the RDBH assay were 97.7%(293/300), 98.2%(164/167), and 97.0%(129/133), respectively. Furthermore, the results indicated that the most common mutations were in codons 531(48.6%), 526(25.4%), 516(8.8%), and 511(6.6%), and the combinative mutation rate was 15(8.3%). One and two strains of insertion and deletion were found among all strains, respectively. Conclusion Our findings demonstrate that the RDBH assay is a rapid, simple and sensitive method for diagnosing RIF-resistant tuberculosis.

Detection of mutation in embB gene of Mycobacterium tuberculosis from clinical isolates of tuberculous patients in China by means of reverse-dot blot hybridization

The relationship between embB mutation of Mycobacterium tuberculosis and ethambutol (EMB) resistance of the clinical isolates of tuberculous patients in China was investigated by reverse dot blot hybridization (RDBH) in addition to evaluating the clinical value with application of PCR-RDBH technique to detect EMB resistance. In the present study, the genotypes of the 258 bp fragments of embB genes from 196 clinical isolates of M. tuberculosis were analysed with RDBH and DNA sequencing. It was demonstrated that 60 out of 91 phenotypically EMB-resistant isolates (65.9%) showed 5 types of missense mutations at codon 306 of embB gene, resulting in the replacement of the Met residue of the wild type strain with Val, Ile or Leu residues. In these mutations, the GTP mutation (38/91, 41.8%) and the ATA mutation (16/91, 17.6%) were the most encountered genotypes. The embB mutation at codon 306 could also be found in 69 isolates of phenotypically EMB-sensitive but resistant to other anti-tuberculous drugs, but no such gene mutation could be found in 36 strains of drug-sensitive isolates. Meanwhile, the concordance with the results of DNA sequencing for one wide-type probe and 5 probes for specific mutations was 100% . It was concluded that the EMB-resistance occurring in most M. tuberculosis is due to appearance of embB mutation at codon 306, and the PCR-RDBH assay was proved to be a rapid, simple and reliable method for the detection of gene mutations, which might be a good alternative for the drug-resistance screening.

Comparison of the Tellgenplex HPV DNA test with the PCR-reverse dot blot assay for human papillomavirus genotyping

Objective: To access the performance of the Tellgenplex human papillomavirus(HPV) DNA test compared to the polymerase chain reaction-reverse dot blot(PCR-RDB) assay for the HPV genotyping.Methods: Sixty cervical swab samples were genotyped by the Tellgenplex HPV DNA test and the PCR-RDB assay.The Tellgenplex HPV DNA test and the PCR-RDB assay can detect 26 and 23 HPV genotypes, respectively.Each sample showed discrepancy was genotyped using sequencing.Results: The percent agreement between the two tests ranged from 83.3% to 100.0% according to different genotype.This showed perfect agreement(>0.81) for high-risk HPV genotypes(35, 39, 45, 53, 56, 59, 66, 68, and 82), substantial agreement(>0.65) for high-risk HPV genotypes(16, 18, 33, 52, and 58) and low-risk HPV genotype 43 between the two assays by the kappa analysis.The positive rates of the two assays for frequent HPV genotypes(16, 35, 39, 45, 52, 53, 58, 59, 66, and 82) were not statistically different, but the PCR-RDB assay showed higher positive rates than the Tellgenplex HPV DNA test for HPV genotypes 81(P<0.05).As for more than 10 positive results by the Tellgenplex HPV DNA test and/or the PCR-RDB assay, the PCR-RDB assay showed higher relative sensitivity and specificity than the Tellgenplex HPV DNA test for the three HPV genotypes(16, 52, and 81).All HPV genotypes that can be detected by only the Tellgenplex HPV DNA test(HPV genotypes 44 and 55) were confirmed by sequencing.Conclusions: In conclusion, our results demonstrated that the PCR-RDB assay which can detect more multiple HPV genotypes in each specimen shows higher relative sensitivity and specificity than the Tellgenplex HPV DNA test, which makes it a better option for routine clinical use.

Dot-Blot Hybridization for Detection of Five Cucurbit Viruses by Digoxigenin-Labelled cDNA Probes

Dot-blot hybridization was applied in this paper to detect five viruses infecting cucurbitaceous crops, Zuccini yellow mosaic virus (ZYMV), Watermelon mosaic virus (WMV), Cucumber mosaic virus (CMV), Papaya ringspot virus- watermelon strain (PRSV-W) and Squash mosaic virus (SqMV), as a good alternative assay in seed health test and epidemiological and transgenic research. Digoxigenin-labelled cDNA probes of the five viruses were synthesized by PCR with the specific primers and applied in dot-blot hybridization to detect five viruses in crude extraction of the infected leaves. And three SqMV probes of different lengths (0.55, 1.6, and 2.7 kb, respectively) were designed to investigate the effect of hybridization. The results showed that the sensitivity for detecting the crude extraction of infected leaves by ZYMV, WMV, CMV, PRSV-W, and SqMV was down to 1:160, 1:160, 1:320, 1:160, and 1:320, respectively. Three SqMV probes of different length showed no differences on the sensitivity and specificity. The digoxigenin-labelled probes prepared by PCR could be used for accurate and rapid identification of 5 viruses infecting cucurbitaceous crops with good stabilities, sensitivities, specificity, and reproducibilities.

A rapid reverse dot blot assay for all 18 β-thalassemia mutations in Chinese population

A set of allele-specific oligonucleotide (ASO) probes used for detecting all 18 β-tha-lassemia mutations found in Chinese was immobilized on two strips of Biodyne C membrane;one containing 7 pairs of oligonucleotide probes specific for the most commonly found mutant al-leles,and the other containing the remaining 11 pairs of ASO_s specific for the less commonlyfound.The membranes were hybridized with β-globin sequences amplified by polymerase chainreaction (PCR) with biotinylated primers,and then treated with Streptavidin-POD conjugateand substrates for color development.The method has been applied successfully to the detectionof all 18 Chinese β-thalassemia mutations and prenatal diagnosis of two high-risk pregnancies ofβ-thalassemia.Patients with homozygous,heterozygous and compound heterozygous alleles ofthese mutations and normal individuals could be easily distinguished by the present method.Us-ing the immobilized-probe format (reverse dot blot),it was able to screen simultaneously multi-ple β-thalassemia mutations of a DNA sample by performing hybridization only once.This assayis simple,rapid and independent of radio-isotopes and can be appplied for all 18 β-thalassemiamutations so far found in Chinese population.It is considered that this method may be usefulfor gene frequency investigation of large numbers of β-thalassemia DNA samples and used as aroutine method in the clinic laboratory.

PCR-Dotblot杂交法直接检测临床病原菌的报告

目的为了寻找临床病原菌系统，检测和鉴别的有力手段。方法用真细菌保守的１６ＳｒＲＮＡ基因为模板，以ＰＣＲ－Ｄｏｔｂｌｏｔ杂交的方法检测临床病原菌。结果它将１６ＳｒＲＮＡ基因的广谱性和变异性并存之特点和ＰＣＲ－Ｄｏｔｂｌｏｔ杂交的敏感性结合起来，对该法的建立进行了探讨，并初步用于临床感染的检测。结论为细菌通用检测法的建立提供了基础。

COMBINED DETECTION OF BREAST CANCER MICROMETASTASES IN THE LYMPH NODES AND BONE MARROW USING REVERSETRANSCRIPTASE CHAIN REACTION AND SOUTHERN HYBRIDIZATION

Objective:The presence of lymph nodes and bone marrow micrometastases of patients with breast carcinoma by immunohistochemistry (IHC) methods has been strongly correlated to early recurrence and shorter overall survival. The aim of this study was to detect micrometastases in matched sample pairs of lymph nodes and the bone marrow of primary breast cancer patients using a more sensitive method, and compare with other clinical parameters. Methods: Cytokeratin 19 (CK-19) gene mRNA expression was detected by reverse trauscriptase-polymerase chain reaction (RT-PCR) and Southern blot hybridization. Human breast cancer cell line T47D was mixed with bone marrow cells at different proportions. The positive detection rate was compared among RT-PCR, Southern blotting and IHC methods. Results: Cytokeratin 19 gene was expressed in all 6 positive control samples, while the expression wasn’t seen in 18 negative control samples. CK-19 IHC positive cells were detected at a dilution of one T47D cell in 5 x105 bone marrow cells, while the sensitivity detected by PCR and Southern blot hybridization was at 1:5x104 and 1:106, respectively. In the samples from the 35 patients, we found CK-19 positive cells in 2 cases (5.7%) by IHC. CK-19 gene expression signal was detected in 14/35 (40%) by RT-PCR, and 17/35 (48.6%) by southern blotting. Four cases were micrometastases positive both in lymph node and bone marrow (11.4%). There was no correlation between CK-1 9 detection and other clinical parameters. Conclusion: combined detection of micrometastases in lymph node and bone marrow by RT-PCR and Southern blotting, using CK-19 as a biological marker is a highly sensitive method for breast cancer.

DETECTION OF BREAST CANCER MICROMETASTASES IN BONE MARROW USING REVERSE-TRANSCRIPTASE CHAINREACTION AND SOUTHERN HYBRIDIZATION

Objective: The aim of this study was to detectmicromethetuses in bone marrow of primary breast cancerpatients, and compare with other clinical parameters.Methods: Cytokeratin 19 (CK-19) genc mRNA expressionwas detected by reverse tra nscri ptase- polymerase chainreaction (RT-PCR) and Southern blot hybridization.Human breast cancer cell line T47D was mixed with bonemarrow cells in different proportions. The positive detectionrate was compared among RT-PCR, Southern blotting andimmunohistochemistry (IHC) methods. Results: Cytokeratin 19 gene was expressed in all 6 positive controlsamples while the expression was not seen in 8 negativecontrol samples. In all 54 patients l4 cases were CK-19positive (25.9%) by RT-PCR, another positive signal wasobtained in 5/54 (9.3%) of bone marrow samples bySouthern blotting. The totul positive cases are 19/54 (35.2% ).CK-19 IHC+ cells were detected at a dilution of one T47Dcen in 5×104 bone marrow cells, while the sensitivitydetected by PCR and Southern blot hybridization was at1:5×105 and 1:1×106, respectively. This demonstrates thatRT-PCR and Southern blotting was at Ieast 20 times moresenstive than the IHC method. The micrometastasespositive rate of the larger tumor size group (>5.0 cm) wassignificantly (P<0.05) greater than that of the smaller tumorsize group (0-2.0 cm). Conclusion: detection of micrometastues in bone marrow by RT-PCR and Southernblotting, using CK-19 as a biological marken is highlysensitive and it is a method to be used for anticipating theprognosis of breast cancer patients.

Accuracy of a reverse dot blot hybridization assay for simultaneous detection of the resistance of four anti-tuberculosis drugs in Mycobacterium tuberculosis isolated from China

Background:Drug resistant tuberculosis poses a great challenge for tuberculosis control worldwide.Timely determination of drug resistance and effective individual treatment are essential for blocking the transmission of drug resistant Mycobacterium tuberculosis.We aimed to establish and evaluate the accuracy of a reverse dot blot hybridization(RDBH)assay to simultaneously detect the resistance of four anti-tuberculosis drugs in M tuberculosis isolated in China.Methods:In this study,we applied a RDBH assay to simultaneously detect the resistance of rifampicin(RIF),isoniazid(INH),streptomycin(SM)and ethambutol(EMB)in 320 clinical M.tuberculosis isolates and compared the results to that from phenotypic drug susceptibility testing(DST) and sequencing.The RDBH assay was designed to test up to 42 samples at a time.Pearson's chi-square test was used to compute the statistical measures of the RDBH assay using the phenotypic DST or sequencing as the gold standard method,and Kappa identity test was used to determine the consistency between the RDBH assay and the phenotypic DST or sequencing.Results:The results showed that the concordances between phenotypic DST and RDBH assay were 95%for RIF,92.8%for INH,84.7%for SM,77.2%for EMB and the concordances between sequencing and RDBH assay were 97.8%for RIF,98.8%for INH,99.1%for SM,93.4%for EMB.Compared to the phenotypic DST results,the sensitivity and specificity of the RDBH assay for resistance detection were 92.4 and 98.5%for RIF,90.3 and 97.3%for INH,77.4 and 91.5%for SM,61.4 and 85.7%for EMB,respeaively;compared to sequencing,the sensitivity and specificity of the RDBH assay were 97.7 and 97.9%for RIF,97.9 and 100.0% for INH,97.8 and 1OO.O% for SM,82.6 and 99.1%for EMB,respectively.The turnaround time of the RDBH assay was 7 h for testing 42 samples.Conclusions:Our data suggested that the RDBH assay could serve as a rapid and efficient method for testing the resistance of M. tuberculosis against RIF,INH,SM and EMB,enabling early administration of appropriate treatment regimens to the affected drug resistant tuberculosis patients.

DETECTION OF STRAND BREAKS OF DNA IN HUMAN EARLY CHORIONIC VILLUS CELLS INDUCED BY DIAGNOSTIC ULTRASOUND USING ^(32)P-LABELED ALU HYBRIDIZATION

Objective To explore if strand breaks of DNA in human early chorionic villus cells in uterus were induced by diagnostic ultrasound and to evaluate the method used for detection of single-stranded breaks and double-stranded breaks in human DNA. Methods 60 normal pregnant women aged 20-30, who underwent artificial abortion during 6-8 weeks of gestation, were randomly divided into 2 experimental groups: All 30 cases were exposed to diagnostic ultrasound in uterus for 10 minutes, and 24 hours later chorionic villi were extracted; the other 30 cases were taken as the control group. Single-stranded DNA and double-stranded DNA in villus cells in all cases were isolated by the alkaline unwinding combined with hydroxylapatite chromatography, and were quantitatively detected using 32 P-labeled Alu probe for dot-blotting hybridization. Results There was no significant difference in quantity and percentage in single-stranded DNA and double-stranded DNA between 2 groups （P>0.05）. 32 P-Alu probe could only hybridize with human DNA, and could detect DNA isolated from as few as 2.5×10 3 chorionic villus cells and 0.45ng DNA in human leukocytes. Conclusion The results suggested that there were no DNA strand damages in human chorionic villus cells when the uterus was exposed to diagnostic ultrasound for 10 minutes. The method,32P-Alu probe for dot-blotting hybridization, was even more specific, sensitive and accurate than conventional approaches.

低比例DNA污染对地中海贫血基因检测结果的影响

目的 研究低比例DNA污染对地中海贫血基因检测结果判读的影响,以及荧光定量PCR(QF-PCR)技术的鉴定污染的能力。方法 2019年1月至2020年1月在中山市博爱医院进行地中海贫血基因检测的11 128名受检者中,选取其中7例确诊基因型分别为-a^(4.2)/aa、-a3.7/--^(SEA)、aWSa/--^(SEA)、a^(CS)α/aa、βCD41-42/βN、a^(CS)a/aa β^(IVS-Ⅱ-654)/βN、a^(QS)a/aa的患者为研究对象,提取外周血DNA,建立污染模型。用QF-PCR技术检测低比例污染样本。分别用PCR-流式荧光杂交方法和Gap-PCR+反向点杂交法检测污染模型。结果 当DNA污染比例小于10%(2 ng/μL)时QF-PCR技术易漏检,而PCR-流式荧光杂交法能提示3.7缺失型(Gap-PCR不提示);反向点杂交膜条法能提示WS、QS突变型α地贫和17种突变型β地贫(PCR-流式荧光杂交法不提示)。结论 两种方法相比较PCR-流式荧光杂交法对检测3.7缺失型更加灵敏,反向点杂交膜条检测法对α、β点突变的检测灵敏度更高。

Reverse Dot Blot Analysis: A Rapid Prenatal Diagnostic Approach for β-thalassemia Mutations in Chinese

The recently developed method of in vitro DNA amplification by PCR coupled with radioactive or nonradioactive ASO probe detection provides a simple approach to the prenatal diagnosis of β-thalassemia. However, the DNA diagnosis of β-thalassemia has remained a complicated problem,because β-thalassemia

某地区女性HPV感染情况及分型分析

目的调查分析山西地区女性HPV的感染情况和常见感染类型,以及不同年龄组中HPV感染的大体情况。从而为该地区宫颈癌的预防、早期诊断和治疗等提供流行病学参考。方法选取送检于太原金域医学检验中心的7030例女性宫颈脱落细胞样本,进行23种HPV基因分型检测。结果7030例样本中共检测出1406例阳性标本,总阳性率为20%。高危型HPV(HR-HPV)共检出1509例(15.06%),低危型HPV(LR-HPV)共检出347例(4.94%)。HR-HPV各亚型检出率从高到低排前五位的分别为HPV52(3.81%)、HPV16(3.29%)、HPV53(2.35%)、HPV58(2.02%)、HPV56(1.59%)和HPV51(1.51%);LR-HPV感染型主要以HPV81(1.35%)、HPV43(1.17%)和HPV42(1.14%)为主。单一亚型的感染率最高为13.90%,双重感染率为3.54%,三重感染率为1.10%,多重感染率为0.50%。HPV检出率最高的是>60~70岁年龄段的女性人群(64.29%),其次为≤20岁的女性人群(54.55%)。结论山西地区女性人群HPV感染率较高,高危型HPV感染占主导位置。HPV感染高发年龄人群应加强宫颈病变的筛查意识,重视HPV的定期复查,以早期发现和预防宫颈癌。

生物技术专业分子生物学实验的建立与思考——以反向点杂交检测β-地中海贫血基因类型为例

本校在面向应用型人才培养的生物技术专业中开设反向点杂交检测β-地中海贫血基因类型的实验项目。从生物安全与阳性基因型多样性的角度出发,实验室将CD41-42(-TTCT)、-28(A>G)、IVS-Ⅱ-654(C>T)、CD71-72(+A)、CD17(A>T)以及野生型共6种常见的基因型克隆至T载体中,建立β-珠蛋白基因突变类型模板库,丰富实验内容。同时笔者对实践教学提出思路,首先,小教师+翻转课堂教学法充分激发学生学习探索的兴趣;其次,在课堂的实验等待时间组织讨论,充分结合理论与实验知识点,以提高教学效果;最后,思政教育与实践同行,培养科学逻辑思维与良好实验习惯,并鼓励科普宣教。

基因芯片对人乳头瘤病毒的快速检测和分型

目的 针对HPV DNA亚型的异质性,建立HPV DNA亚型的基因芯片快速检测方法,为HPV感染病例提供诊断依据。方法 18 种HPV DNA亚型(HPV6、16、18、31、33、35、39、11、45、51、52、53、56、58、42、59、66、68)特异性探针,固定于硝酸纤维素膜制备成基因芯片,生物素标记引物经通用引物介导PCR(GD PCR)扩增HPV DNA, PCR产物与基因芯片经反向点杂交检测HPV亚型;同时采用荧光定量PCR检测HPV6、11、16 和18亚型。结果 31 例标本中,基因芯片的阳性检出率为74.2%,其中HPV6/18、HPV11/16、HPV33/58 和HPV6/11/33多重感染各1 例(3.2%);荧光定量PCR 阳性检出率为67.7%,与前种方法相比较,漏诊率为6.5%。结论 HPV分型基因芯片可1次检测HPV多种亚型,灵敏度高和特异性强,有利于对HPV多重感染的诊断。

贵州三都水族β-地中海贫血筛查及基因分析

目的 了解贵州省三都水族β-地中海贫血的发病率、基因突变类型及分布特点,进一步从分子水平揭示β-地中海贫血多态性。方法 采用"红细胞休克一管定量法"测定红细胞脆性,乙酸纤维素薄膜电泳分离测定HbA2,一分钟碱变性法测定HbF。对贵州省三都水族自治县1 090例当地水族居民,进行β-地中海贫血血液学筛查。用常规酚-氯仿抽提法提取β-地中海贫血携带者DNA,经PCR-反向点杂交法对β珠蛋白基因进行突变分析。结果 在受检的1 090人中,共检出β-地中海贫血携带者49例,检出率为4.50％,男性26例,女性23例,男女比值为1.1:1。经基因分析该地人群的β-地中海贫血基因突变类型主要为CD41-42(TCTT)移码突变(20例,40.82％)和CD17(A→T)无义突变(20例,40.82％),尚有9例(18.36％)不在中国人常见的16种β-地中海贫血突变范围内,待测序。结论 贵州省三都地区水族人群中β-地中海贫血有较高的发生率,且其基因突变类型有明显的地区差异和显著的民族特点,是我国一个较为特殊的β-地中海贫血分布区域。

应用膜反向斑点杂交技术快速检测结核分支杆菌耐乙胺丁醇基因型的研究

应用膜反向斑点杂交技术快速检测结核分支杆菌对乙胺丁醇 (EMB)耐药性。设计与合成用于检测结核分支杆菌耐EMB基因embB的寡核苷酸探针 ,点于硝酸纤维素膜上 ,与结核分支杆菌临床分离株生物素标记的聚合酶链反应 (PCR)产物进行反向斑点杂交 ,并与PCR 单链构象多态性 (PCR SSCP)和PCR 直接测序 (PCR DS)结果比较。对 81株结核分支杆菌临床分离株进行分析 ,31株EMB敏感株中 ,2 6株embB基因的SSCP图谱、膜反向斑点杂交结果与标准株 (H37Rv)完全相同 ;其余 5株SSCP图谱出现泳动变位 ,其中 3株E1b杂交阳性 ,PCR DS分析为embB基因 30 6位密码子ATG→GTG突变 ;2株E1d杂交阳性 ,PCR DS分析为embB基因 30 6位密码子ATG→ATA突变。 5 0株耐EMB菌株中 ,2 4株PCR SSCP图谱与标准菌株相同 ,E1杂交阳性 ;2 6株PCR SSCP图谱出现泳动变位 ,其中 18株E1b杂交阳性 ,2株E1c杂交阳性 ,5株E1d杂交阳性 ,1株E1e杂交阳性 ,未发现E1f杂交阳性 ,与PCR SSCP、PCR DS分析结果一致。突变检出率为 5 2 %。膜反向斑点杂交技术可能成为检测部分结核分支杆菌乙胺丁醇耐药基因型简便、快速的方法。

反向斑点杂交法快速检测甘薯羽状斑驳病毒和甘薯G病毒

【目的】以克隆得到的甘薯羽状斑驳病毒(Sweet potato feathery mottle virus,SPFMV)和甘薯G病毒(Sweet potato virus G,SPVG)基因片段为探针建立反向斑点杂交技术体系,应用于甘薯组培脱毒苗带毒情况检测,为生产优质甘薯组培脱毒苗提供保障。【方法】根据已公布的侵染甘薯的SPFMV和SPVG的核苷酸序列设计两对特异引物,以RT-PCR法从染病的甘薯叶片扩增SPFMV和SPVG的两个片段,并以克隆到的两个病毒片段及内参基因Actin片段为探针建立反向斑点杂交体系。【结果】分别克隆出长度约310和500 bp的片段,经BLAST比对,所获得的310 bp片段为SPFMV的外壳蛋白基因片段,同源性为97%,500 bp片段为SPVG的外壳蛋白基因片段,同源性为99%。分别用带有SPFMV和SPVG片段的重组质粒pUC-SPFMV和pUC-SPVG进行反向斑点杂交,发现不同病毒能获得单一信号,无交叉现象。以染病甘薯和脱毒甘薯苗为样品,用该种病毒的探针进行反向斑点杂交,染病植株样品中能获得单一信号,而脱毒苗甘薯样品未见任何信号,杂交结果与RT-PCR检测结果一致。【结论】用建立的反向斑点杂交技术体系能有效检测甘薯中的SPFMV和SPVG,无交叉信号,可用于甘薯组培脱毒苗的前期检测。

PCR法制备地高辛标记DNA探针斑点杂交检测对虾传染性皮下及造血组织坏死病毒(IHHNV)

利用非放射性标记物地高辛(DIG),通过PCR方法制备了对虾传染性皮下及造血组织坏死病毒(IHHNV)DNA探针,探针长度705bp,标记产量为20ng/μL。通过核酸探针斑点杂交检测方法对此探针特异性及灵敏度进行验证,结果表明,该探针具有较高的灵敏度和较强的特异性,检测IHHNVDNA的检出灵敏度为24.8pg,可检出26.6ng患病对虾组织DNA中的IHHNV,与250.4ng健康虾组织DNA、202.5ng健康虾匀浆液,白斑综合症病毒(WSSV)DNA和肝胰腺细小病毒(HPV)DNA均不发生交叉反应。本方法可应用于健康亲虾、苗种的培育和无特定病原(SPF)对虾种群的选育及IHHNV流行病学调查,并具有较高的应用价值。

对虾WSSV人工感染螯虾及其检测

用对虾白斑综合症病毒(WSSV)人工感染淡水克氏原螯虾(Procambarusclarkii) ,感染组螯虾3～6d内全部死亡。核酸探针点杂交两次检测感染螯虾的鳃、胃、血淋巴 ,阳性检出率分别为92% (92% ) ,89 % (86 % ) ,81 % (75 % ) ,对照为11 % (3% ) ,5 % (5 % ) ,0(0) ;光镜下可观察到感染螯虾的胃、鳃组织的靶细胞核肿大、嗜酸性着染 ,电镜下病变组织细胞核可见形态大小与WSSV一致的病毒粒子 ;病毒核酸原位杂交两次检测感染螯虾的胃、鳃 ,阳性检出率均为100 % ,对照阳性检出率均为0。结果表明 :对虾WSSV可感染淡水克氏原螯虾 。