白羊草ISSR-PCR反应体系的建立与优化

采用正交试验与单因素、双因素设计结合的方法,对白羊草ISSR-PCR反应体系的Mg2+、dNTP、模板DNA、Taq DNA聚合酶及引物5种主要因素进行优化。确立了白羊草最佳反应体系及扩增程序:25μL体系中dNTP 0.2mmol/L、Taq酶1.0U、引物0.6μmol/L、Mg2+2.5mmol/L、DNA模板30ng、10×PCR Buffer 2.5μL;扩增程序:94℃预变性5min,94℃变性45s,50～60℃(退火温度随引物不同而定)退火60s,72℃延伸90s,共35个循环,72℃后延伸5min。     

Distribution of latent bovine herpesvirus 2 DNA in tissues of experimentally infected sheep

The biology of latent infection by bovine herpesvirus 2 (BoHV-2), the agent of mammillitis in cows, remains largely unknown. We herein report attempts to reactivate the latent infection and investigated the sites of BoHV-2 latency in experimentally infected sheep. Ewes inoculated with BoHV-2 in the udder’s skin shed virus for up to five days, developed mammillitis and seroconverted. However, attempts to reactivate latent infection by dexamethasone administration at day 40 pi failed. Nevertheless, viral DNA - and not infectious virus - was detected by PCR in several nerve ganglia and/or regional lymph nodes (LNs) of all animals at day 40 post-reactivation. Likewise, lambs previously inoculated with BoHV-2 in the nose harbored latent viral DNA in trigeminal ganglia, tonsils and regional LNs. These results demonstrate that BoHV-2 establishes latent infection in nerve ganglia and in regional lymphoid tissues, yet virus reactivation is not easily achieved by standard protocols used.     

珍稀濒危植物裸果木RAPD反应体系优化研究

以裸果木新鲜叶片为材料,采用改进CTAB法提取基因组DNA,在参考一般RAPD分析反应程序的基础上,研究了裸果木RAPD分析过程中的影响因素Taq酶、Mg2+、dNTP、引物、模板DNA浓度、变性时间等,建立了适于裸果木RAPD反应的PCR体系:模板DNA为4ng/μL,引物浓度为0.3μmol/L,dNTP浓度为0.5mmol/L,Mg2+浓度为2.0mmol/L,Taq酶用量为1U,ddH2O补足25μL;94℃预变性5min,94℃变性45s,36℃退火40s,72℃延伸1min,共30个循环,最后72℃延伸10min,扩增结果稳定。     

An investigation of the aetiological role of bovine herpesvirus 4 in bovine endometritis

Uteri from 31 infertile cattle were examined for the presence of bovine herpesvirus 4 (BoHV-4) by nested polymerase chain reaction (PCR). Samples were also tested for bacteria, including chlamydiae and Mycoplasma bovis. BoHV-4 was detected by PCR in 27/31 (87.1%) samples, but the presence and amount of viral DNA was not correlated with histological and bacteriological findings. Arcanobacterium pyogenes, Histophilus somni and Pasteurella multocida were isolated from five cows with endometritis. Chlamydiae were detected in four cases (12.9%), but only two of these had endometritis. The study does not support a role for BoHV-4 as primary agent in bovine endometritis.     

Detection of Bovine herpesvirus 4 DNA in aborted bovine fetuses

The presence of Bovine herpesvirus 4 (BoHV-4) was investigated by several methods in 24 aborted bovine fetuses. Polymerase chain reaction (PCR) and in situ DNA hybridization proved the presence of BoHV-4 DNA in 7 (29%) of the fetuses. The BoHV-4 genome was detected in the cytoplasm of splenic lymphocytes and monocytes, and sometimes in renal tubular epithelial cells or hepatic Kupffer cells, in all 7 PCR-positive fetuses. However, BoHV-4-specific monoclonal antibody failed to detect viral antigen in the formalin-fixed, paraffin-embedded tissue samples. No bacterial pathogens were found in the tissues of the BoHV-4-positive fetuses. Fungi were detected in 1 sample, and antibody to bovine viral diarrhea virus was detected in another. These results indicate that BoHV-4 could play a role in reproductive disorders of cattle, including abortion.     

山生柳SSR-PCR反应体系优化

本研究以祁连山4个海拔梯度的山生柳（Salix oritrepha）为材料,采用L9(34)正交试验设计和单因子试验,分析山生柳SSR技术中PCR体系的主要成分对扩增结果的影响,并对引物SHUK123的适宜退火温度进行优化。结果表明,PCR反应体系的最佳条件:20 μL体系中2.0 mmol·L-1 Mg2+ 1 μL,0.10 mmol·L-1 dNTPs 1.5 μL,0.5 U Taq酶用量为1 μL,20 ng·μL-1 DNA模板1 μL, 0.5 μmol·L-1的上下游引物各2 μL,10× Taq Buffer 2 μL,ddH2O加至20 μL。扩增反应程序：94 ℃高温预变性时间3 min,94 ℃变性45 s,Tm(不同退火温度)退火时间45 s,72 ℃延伸30 s,循环数30个,最后72 ℃后延伸时间5 min,4 ℃保温。适宜退火温度为56 ℃。以上结果表明,此反应体系在山生柳PCR扩增中的稳定性和可重复性较好。     

RAPD分子标记鉴定紫花苜蓿品种的反应体系优化

以中苜1号紫花苜蓿(Medicago sativa L.cv.Chongmu No.1)为研究材料,通过对RAPD-PCR反应退火温度、反应体系中的模板DNA、Taq聚合酶、Mg²⁺、dNTP、引物用量的梯度处理,分别对各项单因子进行优化。结果表明,当退火温度为37℃,总反应体积25μl时,各反应物适宜用量为模板DNA80ng,Taq聚合酶1.5U,Mg²⁺6.25×10^-5mmol,dNTP0.3×10^-5mmol,随机引物0.4×10^-5mmol,缓冲液KCl1.25×10^-3mmol,扩增结果清晰、稳定,并且在不同实验室扩增结果具有较好的一致性。     

A specific PCR to differentiate between gE negative vaccine and wildtype bovine herpesvirus type 1 strains

In the context of infectious bovine rhinotracheitis (IBR) control programmes using glycoprotein E (gE) deleted marker vaccines, a PCR assay was developed to allow the genotypic differentiation between wildtype bovine herpesvirus type 1 (BoHV-1) and gE negative strains. This assay is based on the PCR amplification of a 281 bp DNA fragment within the gE gene. The specificity of the amplification was confirmed by restriction endonuclease analysis and nucleotide sequencing of the PCR product. Its ability to determine the gE genotype of BoHV-1 strains was demonstrated on isolates coming from 20 experimental calves infected with four different BoHV-1 strains. This PCR assay may be a useful tool for monitoring the spread of live marker vaccine and the gE genotype of viral field isolates.     

鸡细小病毒与禽呼肠病毒二重PCR检测方法的建立

建立可同时检测鸡细小病毒(Chicken parvovirus,ChPV)与禽呼肠病毒(Avian reovirus,ARV)的二重PCR方法,为防控ChPV与ARV提供技术支撑。根据鸡细小病毒NS1基因和禽呼肠病毒σC基因的保守序列,设计合成两对引物用于检测ChPV和ARV,通过优化二重PCR的反应体系,特异性、敏感性试验评价建立的ChPV与ARV二重PCR。优化后的二重PCR反应体系为:2×PCR Mix 12.5μL,其中ChPV与ARV的上、下游引物各1.0μL,混合模板2.0μL,ddH2O补足25μL;最佳的反应程序为:95℃5min;95℃1min,56.1℃1min,72℃1min,35个循环;最后72℃延伸10min。结果显示,建立的二重PCR能够同时扩增出204bp ChPV和405bp ARV片段;该方法对ChPV与ARV的检测敏感性分别达到58fg和53fg,但对鸡新城疫病毒、H9亚型禽流感病毒、马立克病病毒、鸡传染性喉气管炎病毒、鸡传染性支气管炎病毒等病原体均无特异性扩增,对ChPV与ARV混合感染的临床阳性病料的检测结果与各病毒单项PCR检测结果符合率为94%以上。建立的二重PCR可用于ChPV与ARV感染的快速鉴别诊断。     

Acute and latent infection by bovine herpesvirus type 5 in experimentally infected goats

The ability of alphaherpesviruses to infect different ruminant species may have important implications for control/eradication efforts. Serological data indicate that goats may be naturally infected with bovine herpesviruses. To investigate the susceptibility of goats to bovine herpesvirus-5 (BoHV-5), 3-4-month-old kids were inoculated intranasally with each of three Brazilian BoHV-5 isolates (G1, n=8; G2, n=5; G3, n=5). The acute infection was characterized by virus shedding in nasal secretions for up to 14 days (titers up to 10(5.97)TCID(50)/mL), mild respiratory signs and conjunctivitis. All animals seroconverted to BoHV-5, developing virus neutralizing (VN) titers from 4 to 32 to the homologous viruses. At day 60 post inoculation (pi), two animals from each group were euthanized for tissue collection and the remaining goats were submitted to dexamethasone administration (0.4 mg kg(-1) for 5 days). Dexamethasone treatment resulted in virus reactivation in 9 out of 12 animals, as ascertained by virus shedding and/or by increase in VN titers. Virus shedding was detected in 8/12 animals and lasted from 1 to 9 days. Latent viral DNA was detected by PCR in the olfactory bulb and/or trigeminal ganglia of 6/6 goats euthanized at day 60 pi and in 12/12 animals euthanized 40 days post-dexamethasone. These results show that young goats are susceptible to BoHV-5 and may shed virus upon reactivation of latent infection. Thus, it is reasonable to expect that goats raised in close contact with cattle in areas where BoHV-5 is endemic may be infected and therefore should be considered potential reservoirs of the virus.     

Characterization of Bovine herpesvirus type 4 isolated from cattle with mastitis and subclinical infection by the virus among cattle

An outbreak of contagious mastitis occurred among cattle on a farm, and bovine herpesviruses were isolated from the affected mammary tissues, scabs and abscess discharge of the cattle. A bovine herpesvirus type 4 (BoHV-4)-specific fragment was amplified from the isolates by polymerase chain reaction (PCR). Restriction endonuclease analyses demonstrated that the isolates were related to Movar-like European type BoHV-4. To determine the ratio of BoHV-4 subclinical infection in the cattle, a genomic survey was performed by PCR for cattle that were moved to the animal hygiene service station in Ibaraki prefecture. The BoHV-4 genome was occasionally detected in peripheral blood leukocytes, lymph nodes and nervous tissues. The rate of BoHV-4 subclinical infection was relatively high in the cattle.     

Evaluation of polymerase chain reaction diagnosis of Cryptosporidium spp in dairy cattle and wildlife

This study investigated the utility of the polymerase chain reaction (PCR) protocol as a screening test for Cryptosporidium spp in 125 fecal samples from dairy cattle and wild rodents. Samples initially examined by fecal flotation and ELISA were evaluated using four PCR protocols (18S SSU rRNA, TRAP-C2, HSP70, and COWP), and the relative accuracy and agreement of PCR protocols was assessed. Although PCR can be both highly sensitive and accurate, the ability of these protocols to accurately detect DNA in samples can vary. A combination of techniques may be the best choice for to screen samples for this parasite.     

Detection of bovine herpesvirus type 4 antibodies and bovine lymphotropic herpesvirus in New Zealand dairy cows

AIM: To detect the presence of bovine herpesvirus (BoHV) type 4 in New Zealand dairy cows with clinical metritis.

METHODS: Serum samples taken from 92 dairy cows with clinical metritis, each from a different farm, were tested for the presence of antibodies against BoHV-4 using a commercially available, indirect ELISA. Peripheral blood mononuclear cells (PBMC) were collected from 10 BoHV-4 seropositive cows, and PBMC were examined by a pan-herpesvirus nested PCR to detect herpesvirus. PCR products were sequenced directly and a proportion of the PCR products were cloned and sequenced to identify the virus present.

RESULTS: Antibodies to BoHV-4 were detected in 23/92 (25%) serum samples. The pan-herpesvirus PCR was positive in 8/10 PBMC samples. Cloning and sequencing identified that all of the eight PCR-positive PBMC contained bovine lymphotropic herpesvirus (BLHV); no BoHV-4 DNA was detected.

CONCLUSIONS: This study reports the finding of the presence of apparent antibodies to BoHV-4, and BLHV DNA in New Zealand dairy cows affected by metritis.

CLINICAL RELEVANCE: Bovine herpesvirus type 4 and BLHV are reported to have the potential to cause reproduction failure in cows. This is the first report of apparent BoHV-4 antibodies, and BLHV in New Zealand. The importance and epidemiology of these viruses in cattle in New Zealand requires further investigation.     

Susceptibility of mice to bovine herpesvirus type 5 infection in the central nervous system

Bovine herpesvirus type 5 (BoHV-5) is an important pathogen that causes meningoencephalitis in cattle. Few studies have used the mouse as a model for BoHV-5 infection. Despite the fact that BoHV-5 can infect mice with immune deficiencies, little is known about viral replication, immune response, and the course of infection in the central nervous system (CNS) of wild-type mice. Therefore, the aim of this study was to evaluate the response in the CNS of BALB/c mice acutely infected with BoHV-5 at different days post-inoculation (dpi). BoHV-5, when inoculated intracranially, was able to infect and replicate within the CNS of BALB/c mice. Until 15 dpi, the mice were able to survive without showing prominent neurological signs. The infection was accompanied by a Th1 immune response, with a significant expression of the cytokines IFN-γ and TNF-α and chemokine CCL-2. The expression of these cytokines and chemokines was most significant in the early course of infection (3 and 4 dpi), and it was followed by meningoencephalitis with perivascular cuffing and periventriculitis, composed mainly of macrophages and lymphocytes. After the expression of cytokines and chemokine, the mice were able to curb BoHV-5 acute infection in the brain, since there was a decrease in the number of BoHV-5 DNA copies after 3 dpi and viable viral particles were not detected after 6 dpi. Importantly, BoHV-5 was able to infect the trigeminal ganglia during acute infection, since a large number of BoHV-5 DNA copies were detected on 1 and 2 dpi.     

Establishment and Application of Mycobacterium Typing Triple PCR Detection Method

This study was aimed to establish a triple PCR method to rapidly identify Mycobacterium species, and evaluate its testing reliability.Three pairs of primer that were respectively specific to rv 3036c, rv 1970f and pncA genes of Mycobacterium were designed to establish a triple PCR for preliminary identification of Mycobacterium tuberculosis(M.tuberculosis), Mycobacterium bovis(M.bovis) and other Mycobacterium spp.PCR products were the expected sizes of 500(rv3036c), 125(rv1970f) and 249 bp(pncA), and contained two DNA bands(500 and 125 bp) with M.tuberculosis DNA template, two DNA bands(500 and 249 bp) with M.bovis DNA template.No band or non-specific band appeared with Mycobacterium spp.except M.tuberculosis and M.bovis DNA templates.The sensitivity of the triple PCR was calculated to 50 pg/μL template of genomic DNA.86 acid-fast bacteria were detected by the triple PCR, 16S rDNA and ITS gene sequencing, growth test and biochemical test, and the results were consistent between triple PCR and 16S rDNA and ITS gene sequencing.The detecting accuracy of triple PCR was 100%, and higher than growth test and biochemical test.     

紫花苜蓿ISSR-PCR反应体系的建立与优化

通过优化影响紫花苜蓿(Medicago sativa L.)ISSR-PCR的主要参数,建立适于紫花苜蓿的ISSR反应体系和扩增程序。在20μL体系中各反应物的最适含量为:15 ng模板DNA,0.2 mmol/L dNTP,0.4μmol/L ISSR引物,0.8 U Taq DNA聚合酶,2μL 10×PCR Buffer,1.5 mmol/L MgCl₂,2.5%去离子甲酰胺。PCR扩增程序为:94℃预变性4 min,94℃变性30 s,62℃(62℃~58℃)退火45 s,72℃延伸1 min 45 s,共11个循环,每个循环退火温度降1℃;94℃变性30 s,52℃(52℃~48℃)退火45 s,72℃延伸1 min 45 s,共24个循环;72℃延伸5 min,25℃保温。     

Isolation and characterisation of cervine herpesvirus-1 from red deer semen

AIM: This communication describes the isolation of herpesvirus during routine export examination of semen collected from red deer stags in New Zealand. METHODS: Virus isolation was carried out using bovine embryonic lung (BEL) cells and viruses were characterised by direct immunofluorescense, restriction-fragment-length polymorphism analysis (RFLP), polymerase chain reaction (PCR) analysis and nucleotide sequencing. RESULTS: Herpesvirus was isolated from red deer semen on 2 different occasions from different animals. In both cases the virus was identified as cervine herpesvirus-1 (CvHV-1), based on RFLP, PCR and sequence analysis. Nucleotide sequence analysis of the glycoprotein-D gene showed 99.7% homology to the Banffshire strain of CvHV-1 and 89.5%, 89.2%, 85.3% and 79.6% homology to bovine herpesvirus 1.2 (BoHV-1.2), bovine herpesvirus 1.1 (BoHV-1.1), cervine herpesvirus-2 (CvHV-2) and caprine herpesvirus-1 (CpHV-1), respectively. CONCLUSION: This is the first time that CvHV-1 has been isolated in New Zealand. Its inclusion in serological surveys will allow the prevalence of CvHV-1 in the red deer population to be assessed in this country. The clinical significance of CvHV1 infection in New Zealand red deer herds has yet to be determined.     

分枝杆菌分型三重PCR检测方法的建立及应用

本研究旨在建立一种快速鉴定分枝杆菌的三重PCR方法,并比较分析其在临床检测中的可靠性。根据已发表的结核分枝杆菌、牛分枝杆菌和非洲分枝杆菌rv 3036c基因,结核分枝杆菌rv 1970f基因(RD7)和牛分枝杆菌pncA基因的序列,改造并设计合成了3对特异性扩增引物,建立了一种能对分枝杆菌样品进行初步鉴定的三重PCR方法。结果显示该方法可针对rv 3036c、rv 1970f和pncA基因分别扩增出大小为500、125和249 bp的目的片段,能特异性检测出结核分枝杆菌(500和125 bp两条带)和牛分枝杆菌(500和249 bp两条带),并可将结核分枝杆菌、牛分枝杆菌与其他分枝杆菌加以区分。本方法的检测灵敏度为50 pg/μL模板基因组DNA。对86株抗酸染色阳性菌进行三重PCR鉴定,鉴定结果与细菌16S rDNA和ITS序列测定结果一致,检测准确度为100%,优于生长特征和生化试验鉴定。     

假俭草ISSR-PCR反应体系的建立与优化

以假俭草为材料,对影响ISSR—PCR扩增结果的因素进行了探讨,建立了适合假俭草ISSR—PCR分析的最佳反应体系。表明在20弘L总体积中,包含40ng模板DNA、ISSR引物0．4umol／L、dNTPs0．1mmol／L、Mg^2＋1．0mmol／L、0．1U TaqDNA聚合酶和10×buffer 2．0uL。扩增条件为．94℃预变性5min;94℃变性45s,55℃退火45s,72℃延伸1．5min,35个循环;72℃延伸7min。     

铜绿假单胞菌flgE基因PCR检测方法的初步建立

为建立一种基于铜绿假单胞菌flgE基因的PCR检测方法,本试验根据GenBank中已发表的铜绿假单胞菌flgE基因序列,设计合成了1对特异性引物,由铜绿假单胞菌基因组DNA中扩增获得了目的基因。从退火温度、循环次数、Mg2+浓度、dNTPs浓度和引物浓度5个方面优化了反应条件,并检测了该方法的特异性和敏感性。结果成功扩增出了铜绿假单胞菌1 400 bp的flgE特异性基因片段,最佳退火温度、循环次数、Mg2+浓度、dNTPs浓度和引物浓度分别为56℃、30个循环、1.6 mmol/L、0.2 mmol/L和0.3μmol/L。特异性试验表明,仅铜绿假单胞菌中可扩增出目的片段,而多杀性巴氏杆菌、鼠伤寒沙门氏菌、志贺氏菌、致病性大肠杆菌和金黄色葡萄球菌中均未扩增出相应片段。敏感性试验结果表明,本方法可检测到最低10 pg/μL的铜绿假单胞菌基因组DNA以及100 CFU/mL的病原菌。