牛瑟氏泰勒虫二温式PCR快速检测技术的建立及初步应用

为建立一种牛瑟氏泰勒虫快速检测技术,根据GenBank上已发表的牛瑟氏泰勒虫P23表面蛋白基因序列(D84447)设计1对特异性引物,扩增出大小为244 bp的基因片段,经克隆、测序分析,与已知基因序列同源性为100%。用该对引物建立的牛瑟氏泰勒虫二温式PCR能检测出的最高敏感度为171 fg/μL,与牛新孢子虫、弓形虫和卵形巴贝斯虫不产生交叉反应,对48份临床血液样本进行检测,阳性检出率为66.67%。用同一对引物对28份临床血液样本分别进行二温式PCR和三温式PCR检测,阳性符合率为95%,总符合率为96.43%。结果表明,该方法具有快速、敏感、特异等优点,可用于牛瑟氏泰勒虫病的快速临床诊断及流行病学调查。     

羊环形泰勒虫单管套式PCR检测方法的建立及初步应用

为了建立羊环形泰勒虫单管套式PCR检测方法并初步应用于临床检测。根据GenBank上发表的环形泰勒虫Tams1基因序列,设计内、外2对特异性引物,进行单管套式PCR检测方法研究,并进行了特异性、敏感性试验及临床应用试验。结果表明：该检测方法能够扩增的基因片段大小为476 bp,与GenBank收录的相关序列同源性高达93%~98%,而与附红细胞体、新孢子虫、艾美耳球、弓形虫RH株相关病原基因组均无交叉反应,能够检测出DNA的最小量为12 fg。并对57份临床样品进行了检测,检测阳性率为40.4%,高于常规PCR和血涂片镜检测,表明该检测方法具有较高的敏感性,可用于羊环形泰勒虫感染的早期诊断,有较好的临床应用价值。     

牛环形泰勒虫新疆株Tams1基因真核表达载体的构建及免疫反应性研究

研究采用PCR 方法从焦虫病患牛的全血基因组中扩增得到846 bp 的Tams1 基因片段,将其克隆至真核表达载pcDNA3.1(+),构建Tams1基因的真核表达质粒.经测序验证后, 将Tams1基因的真核表达质粒尾静脉注射小白鼠进行Tams1 基因的瞬时表达.取接种小鼠的肝脏提取总RNA,采用RT-PCR 扩增目的条带;用重组质粒pcDNA3.1(+)-Tams1 皮下注射免疫小白鼠4 次后,进行免疫抗体检测.试验结果表明重组质粒pcDNA3.1(+)- Tams1含有完整的Tmas1基因片段.用该重组质粒免疫小鼠56 d后,小鼠血清中抗重组质粒pcDNA3.1(+)- Tams1的抗体效价可达1∶12 000以上,说明该重组质粒具有很强的抗原性.经Western-blot检验可得到抗原-抗体复合物产生的特异性条带,说明该重组质粒pcDNA3.1(+)- Tams1具有免疫原性.     

牛瑟氏泰勒虫HSP70基因的克隆及原核表达

根据GenBank(D12692.1)上发表的牛瑟氏泰勒虫HSP70基因序列设计、合成1对特异性的引物,采用PCR方法扩增牛瑟氏泰勒虫HSP70基因片段,将扩增产物与pMD18-Tsimple载体连接,重组质粒经PCR、酶切鉴定后测序;用pGEX-4T-1表达载体构建重组质粒pGEX-HSP70,经IPTG诱导表达后进行SDS-PAGE、Western-blot分析。结果表明:扩增的HSP70基因与D12692.1序列同源性为99.3%;表达的融合蛋白分子质量约为68ku,而且可与牛瑟氏泰勒虫阳性血清发生特异性反应。     

Haemolytic anaemia in cattle in NSW associated with Theileria infections

Several outbreaks of anaemia, jaundice, abortion and mortality in cattle in New South Wales were attributed to the intracellular parasite, Theileria buffeli . Disease occurred predominantly in periparturient animals that had been moved from inland to coastal areas. Diagnosis was made via exclusion of other causes of haemolytic anaemia and observation of the parasite in blood smears. Treatments included both registered and non-registered products. There is a possibility of a new strain of Theileria sp. in Australia and the possible vectors encountered in NSW are discussed.     

牛瑟氏泰勒虫套式PCR检测方法的建立及初步应用

根据GenBank上发表的牛瑟氏泰勒虫P33基因序列设计2对特异性引物,建立套式PCR检测方法。该方法与弓形虫RH株、猪附红细胞体和犬新孢子虫均无交叉反应,能检测到的最低DNA量为15 fg。在75份临床样本检测中,62份为阳性,阳性率为82.7%。由此可见所建立的套式PCR检测方法具有较高的敏感性和特异性,可用于牛瑟氏泰勒虫急性感染和隐性感染的早期诊断,为该病的临床检测、流行病学调查、进出口检疫和实验室研究提供了新的技术手段。     

环形泰勒虫感染细胞抑制性消减文库的构建及ESTs分析

【目的】环形泰勒虫（Theileria annulata）可以感染牛B淋巴细胞、树突状细胞和巨噬细胞,并可使被感染细胞发生转化,体外培养时可获得类似肿瘤样细胞的无限增殖能力。本研究通过构建环形泰勒虫转化和非转化宿主细胞抑制性消减文库,筛选环形泰勒虫裂殖体基因及转化细胞与宿主正常细胞之间的差异表达基因。【方法】以环形泰勒虫裂殖体转化细胞和非感染牛外周血单个核细胞（即非转化宿主细胞）为试验材料,提取总RNA和mRNA,反转录合成cDNA;然后分别作为tester和driver,进行抑制性消减杂交（SSH）,构建环形泰勒虫转化和非转化宿主细胞抑制性消减文库;对随机挑取的阳性克隆进行测序及生物信息学分析,并利用实时荧光定量PCR对文库部分差异基因进行验证。【结果】通过对文库454个阳性克隆进行测序,共获得了有效表达序列标签（ESTs）364条,大小主要分布在350-1 200 bp之间;将这些ESTs序列在GenBank中进行BLASTn网上序列比对,其匹配于192条基因序列;其中包括环形泰勒虫序列60条(11条为虫体蛋白酶基因序列、10条为膜蛋白基因序列、7条为假设蛋白基因序列、5条为凋亡相关虫体蛋白基因序列、5条为核糖体蛋白基因序列、4条为细胞周期蛋白基因序列、4条为虫体抗原基因序列和虫体其它基因序列14条)、牛基因序列131条（其中19条为肿瘤相关蛋白基因序列）和1条未知序列;其中已有功能注释的ESTs 285条,再将已知功能的ESTs通过WEGO软件从生物学过程（biological process）、细胞组成（cellular component）和分子功能（molecular function）3个部分进行GO聚类分析,结果表明,宿主细胞差异基因主要集中在细胞、细胞进程、结合、催化、代谢进程、生物调节等功能方面。另外,通过对部分环形泰勒虫裂殖体转化宿主细胞差异基因进行荧光定量PCR分析,结果表明,肿瘤相关基因HCLS1和SENP5在转化宿主细胞中转录水平分别是非感染牛PBMCs(非转化宿主细胞)的2.06和1.32倍。【结论】利用SSH技术,成功构建了环形泰勒虫感染宿主细胞的抑制性消减文库,筛选获得了转化宿主细胞和环形泰勒虫裂殖体的表达基因,并通过荧光定量PCR分析获得了2个可能参与宿主细胞转化的基因,为进步探索环形泰勒虫与宿主细胞相互作用的分子机制奠定了基础。     

牛瑟氏泰勒虫P23主要表面蛋白基因的克隆及原核表达

[目的]研究牛瑟氏泰勒虫P23表面蛋白基因的克隆及原核表达.[方法]采用PCR方法扩增牛瑟氏泰勒虫中国延边株P23基因片段,将扩增产物克隆人pMD18-T载体构建重组质粒pMD18-P23经PCR、双酶切鉴定后测序;将目的基因片段亚克隆人表达载体pGEX-4T-1构建重组表达质粒pGEX-4T-P23,转化宿主菌BL21获得重组菌.通过对诱导条件的优化,根据SDS-PAGE确定表达蛋白的最佳表达条件;Western-blotting检测表达蛋白的反应原性.[结果]所克隆的牛瑟氏泰勒虫P23基因片段长507 bp,与牛瑟氏泰勒虫日本株P23基因的核苷酸同源性达99.4%,表达的融合蛋白大小约为46 ku;诱导时机以接种培养后2 h为最佳,诱导时间以6 h为最佳,诱导温度以34℃为最佳,0.008～1.000 mmol/L的IPTC对表达量的影响不大.Western blotting检测表明该蛋白具有较好的抗原性.[结论]为牛瑟氏泰勒虫病的免疫学诊断和预防等研究奠定了基础. Abstract： [Objective] The aim was to study cloning and prokaryotic expression of P23 major surface protein gene of Theileria sergenti.[Method]A pair of specific primers was designed according to the sequence of P23 major surface protein of T.sergenti (D84447).The P23 gene was amplified by PCR from genomic DNA of T.sergenti and cloned into pMD18-T vector to construct recombinant clonal vector pMD18-P23.Positive clones were identified by PCR screening and restriction digestion.A recombinant expression plasmid pGEX-4T-P23 was constructed by subcloning the cloned P23 gene into the linearized pGEX-4T-1 vector and transformed into E.coil BL21.After introduction by IPTG,the expressed fusion protein was identified by SDS-PAGE and Western-blotting. [Result] The cloned gene has a total length of 507 bp.Sequencing result showed that the nucleotide sequence of the cloned P23 gene shared 99.4% identity with that of P23 published in GenBank (D64447).The expressed fusion protein was 46 ku in molecular mass.Induction opportunity of zhours after culture inoculation was the best,the induction time of 6 h was the best,and induction temperature of 34 ℃ was the best as well,IPTG of 1 mmol/L had little effect on the expression.Western-blotting indicated that recombinant protein was recognized by specific antibody. [Conclusion] This study would lay a foundation for further research on the prevention and diagnose of T,sergenti.     

牛瑟氏泰勒虫环介导等温扩增检测方法的建立

为建立快捷、灵敏的牛瑟氏泰勒虫(T.sergenti)检测方法,本研究以感染牛T.sergenti的阳性血液为试验材料,建立了牛T.sergenti P33表面蛋白基因环介导等温扩增(LAMP)检测技术,并优化了LAMP的各反应条件,进行了敏感性和特异性试验。结果显示,扩增产物经显色、电泳、酶切鉴定后,LAMP方法扩增牛T.sergenti产物检测管显色后呈阳性反应,最低检测量为2.3fg/μL模板DNA,比普通PCR高10倍,牛T.sergenti LAMP产物电泳后呈特征性梯状条带,而弓形虫等对照组均无扩增条带。说明本研究建立的LAMP方法具有灵敏、特异、快速等优点,适合于牛T.sergenti的检测。     

Fatal cases of Theileria annulata infection in calves in Portugal associated with neoplastic-like lymphoid cell proliferation

This study was carried out to investigate fifteen cases of acute lethal infection of calves (≤ 4 months of age) by the protozoan parasite Theileria (T.) annulata in the south of Portugal. Calves developed multifocal to coalescent nodular skin lesions, similar to multicentric malignant lymphoma. Infestation with ticks (genus Hyalomma) was intense. Theileria was seen in blood and lymph node smears, and T. annulata infection was confirmed by isolation of schizont-transformed cells and sequencing of hypervariable region 4 of the 18S rRNA gene. At necropsy, hemorrhagic nodules or nodules with a hemorrhagic halo were seen, particularly in the skin, subcutaneous tissue, skeletal and cardiac muscles, pharynx, trachea and intestinal serosa. Histologically, nodules were formed by large, round, lymphoblastoid neoplastic-like cells. Immunohistochemistry (IHC) identified these cells as mostly CD3 positive T lymphocytes and MAC387 positive macrophages. A marker for B lymphocytes (CD79αcy) labeled very few cells. T. annulata infected cells in these nodules were also identified by IHC through the use of two monoclonal antibodies (1C7 and 1C12) which are diagnostic for the parasite. It was concluded that the pathological changes observed in the different organs and tissues were caused by proliferation of schizont-infected macrophages, which subsequently stimulate a severe uncontrolled proliferation of uninfected T lymphocytes.