结核分枝杆菌Zmp1基因原核表达载体的构建及表达鉴定

目的构建结核分枝杆菌锌离子依赖的金属蛋白酶1(Zmp1)基因的原核表达载体,并在大肠杆菌中进行表达。方法以卡介苗(BCG)基因组DNA为模板,采用PCR法扩增Zmp1基因;定向克隆到原核表达载体pET-32a(+)的多克隆位点中,构建重组原核表达质粒pET-32a(+)-Zmp1;转化入大肠杆菌BL21(DE3)中经IPTG诱导表达,表达产物经SDS-PAGE和Western blot法鉴定。结果PCR法扩增出Zmp1基因;重组表达质粒经双酶切及基因测序鉴定构建正确;表达的重组Zmp1融合蛋白相对分子质量(Mr)约为94 000,大小与预期融合蛋白一致;重组Zmp1融合蛋白可与His标签单克隆抗体特异性结合。结论成功构建了Zmp1基因原核表达载体,并在大肠杆菌BL21(DE3)中获得重组Zmp1融合蛋白表达。     

结核分枝杆菌PPE68蛋白的表达、鉴定及抗血清的制备

目的在大肠杆菌中表达结核分枝杆菌PPE68蛋白,鉴定并纯化重组rPPE68蛋白后免疫新西兰大白兔,制备兔抗PPE68多克隆抗体。方法将已经过鉴定的重组原核表达质粒pET32a(+)-PPE68转化至大肠杆菌BL21中,IPTG诱导大量表达PPE68蛋白。对表达蛋白进行鉴定后利用亲和层析法进行纯化。以纯化后重组rPPE68为免疫抗原,与弗氏不完全佐剂等体积混合,采用皮下多点注射法免疫新西兰大白兔,于第3次免疫后的第7天采血。用凝集实验与Western-blot检测抗血清的特异性,并用双向免疫扩散法测定抗血清效价。结果在大肠杆菌中表达的目的产物经SDS-PAGE分析,在相对分子质量57 000处可见特异性条带,免疫印迹分析证实表达的目的蛋白可与结核分枝杆菌H37Rv株感染小鼠的血清发生反应。纯化的rPPE68蛋白免疫新西兰大白兔后,凝集反应与Western-blot证实了抗血清的特异性,双向免疫扩散法测得血清效价为1∶16。结论已成功表达结核分枝杆菌PPE68蛋白,制备了特异性兔抗PPE68多克隆抗体,对结核病的早期诊断提供了一种新的思路。     

结核分枝杆菌调节蛋白RelA的原核表达及多克隆抗体制备

目的:克隆编码结核分枝杆菌调节基因RelA并在大肠杆菌中表达,纯化后制备兔抗RelA的抗体。方法:利用PCR从结核分枝杆菌H37Rv株中扩增RelA基因,构建重组表达质粒pET-32a(+)-RelA;以重组质粒转化大肠杆菌BL21(DE3),筛选阳性重组菌株,IPTG诱导目的蛋白表达,在变性条件下对目的蛋白进行镍离子亲和层析纯化,通过SDS-PAGE和Westem blot鉴定目的蛋白的表达及反应原性;以表达的RelA蛋白免疫家兔,制备抗RelA的多克隆抗体并进行效价及特异性鉴定。结果:扩增了RelA基因,克隆于表达载体pET-32a(+)中,PCR筛选和酶切鉴定获得阳性克隆,测序证实正确。经诱导在大肠杆菌中表达出相对分子质量(Mr)为120 000的目的蛋白;纯化的RelA免疫家兔后,能有效地刺激特异性抗体的产生,抗血清的效价达到1∶6 400以上,且具有良好的特异性。结论:已成功构建RelA基因的原核表达载体,并在大肠杆菌中获得高效表达;制备出兔抗RelA抗体,效价及特异性均良好,为进一步研究RelA蛋白在结核病中的致病机制奠定了基础。     

结核分枝杆菌Ag85B基因的克隆及真核表达载体的构建

目的 构建以结核分枝杆菌分泌蛋白Ａｇ８５Ｂ基因为基础的核酸疫苗。方法 采用聚合酶链反应从结核杆菌Ｈ３７Ｒａ株基因组中,扩增出蛋白Ａｇ８５Ｂ的成熟蛋白的编码基因,用限制性内切酶消化后,插入克隆载体ｐＵＣ１９中。经酶切鉴定与序列测定证实后,以亚克隆法构建于真核表达载体ｐｃＤＮＡ３的相应酶切位点。结果 结核分枝杆菌Ｈ３７Ｒａ株Ａｇ８５Ｂ成熟蛋白的编码基因经序列测定证实,与Ｅｒｄｍａｎ株完全一致;用Ｅｃｏ     

结核分枝杆菌Rv0073基因在大肠杆菌中的表达及纯化

目的 构建结核分枝杆菌(MTB) Rv0073基因原核表达载体并进行表达和纯化.方法 以MTB H37Rv基因组DNA为模板,采用聚合酶链反应(PCR)扩增目的基因片段,构建原核表达载体pET26b-Rv0073,经测序确定无误后转化至大肠杆菌(E.coli)感受态细胞BL21中.用聚丙烯酰氨凝胶电泳(SDS-PAGE)方法检测重组蛋白表达,检测异丙基-β-D-硫代半乳糖苷(IPTG)诱导不同时间、不同温度条件下重组蛋白表达量.采用His镍磁珠进行外源蛋白小量纯化.结果 成功构建重组表达质粒,重组蛋白经IPTG诱导后,2h开始明显表达且表达量无时间依赖性,在不同温度诱导下,重组蛋白的表达量随温度的增高而减少.重组蛋白以包涵体形式存在,经His镍磁珠纯化后获得重组蛋白.结论 成功构建并表达Rv0073蛋白,为后续Rv0073的大量纯化及其功能研究奠定了基础.     

结核分枝杆菌cfp10-esat6融合基因原核表达载体的构建及表达

构建结核分枝杆菌cfp10-esat6融合基因及其原核表达载体,在大肠杆菌中表达融合蛋白CFP10-ESAT6。用基因拼接(GeneSOEing)法扩增cfp10-esat6融合基因,并将其定向克隆至原核表达载体pGEX-4T-1,构建原核表达重组质粒pGcfp10-esat6。重组子经限制性内切酶分析、聚合酶链式反应及测序鉴定后转化宿主菌大肠杆菌BL21,IPTG(isopropy-β-D-thiogalactoside,异丙基硫代-β-D半乳糖苷)诱导表达约42kDa带谷胱苷肽硫转移酶(Glutathione-S-TransferasesGST)蛋白标签的rCFP10-ESAT6融合蛋白,经谷胱苷肽硫转移酶融合蛋白纯化试剂盒得到纯化的融合蛋白,产物进行SDS-PAGE电泳、Western-blot鉴定。重组质粒pGcfp10-esat6中目的基因测序结果与报道序列相同;在大肠杆菌中以可溶性非包涵体形式表达;表达量约占菌体总蛋白的40%,表达蛋白纯化后获得纯度为90%左右的重组蛋白;Western印迹结果证实重组蛋白与确诊的结核病患者血清发生特异免疫反应。本研究成功构建了原核表达载体pGcfp10-esat6,获得了rCFP10-ESAT6融合蛋白,为rCFP10-ESAT6融合蛋白在结核病诊断中的应用奠定了基础。     

结核分枝杆菌保护性肽表位KLIANNTRV多聚体重组表达及鉴定

目的 重组表达结核分枝杆菌保护性肽表位KLIANNTRV二聚体、四聚体、八聚体,以进一步探讨其免疫效应.方法 选取结核分枝杆菌抗原表位KLIANNTRV,引入Th表位PADRE及木马肽序列(RKKRRQRRR),并以RVKR序列作为接头,分别合成结核分枝杆菌保护性肽表位KLIANNTRV二聚体、四聚体、八聚体全基因序列,经PCR扩增后分别插入融合表达载体pGEX-4T-1,将重组质粒转人大肠杆菌BI21并以IPTG诱导表达,进一步经GST亲合层析柱纯化,经SDS-PAGE和Westerm-blot鉴定重组表达蛋白.结果 成功构建了结核分枝杆菌保护性表位KLIANNTRV二聚体、四聚体、八聚体的表达质粒,并经IPTG诱导表达了大小约为20000、32000、54000的融合蛋白.结论 结核分枝杆菌保护性肽表位KLIANNTRV多聚体的重组表达为进一步开发结核疫苗提供有价值的依据.     

结核分枝杆菌毒力分泌基因Rv3872重组卡介苗的构建及表达

目的:构建结核分枝杆菌Rv3872的原核重组表达质粒pET-3872并对其进行表达及鉴定。构建表达结核分枝杆菌抗原蛋白Rv3872即PE35的重组卡介苗。方法:应用PCR技术扩增Rv3872基因,定向克隆入pET32a(+)并转化E.coli BL21(DE3)菌株,测序后用IPTG诱导蛋白表达,通过SDS-PAGE和Western blot对目的蛋白进行检测及鉴定。用纯化蛋白免疫新西兰大白兔制备多克隆抗体。构建重组穿梭表达质粒pMV-3872,将重组质粒电穿孔进入卡介苗,对重组卡介苗进行诱导表达用SDS-PAGE和Western blot检测和鉴定目的蛋白。结果:表达融合蛋白的pET-3872质粒构建成功,重组蛋白经Western blot检测出特异性阳性信号。重组卡介苗BCG-3872构建成功,热诱导表达后经SDS-PAGE和Western blot,在培养上清中检测到目的蛋白。结论:成功构建了重组质粒pET32a(+),并在大肠杆菌中表达了PE35蛋白,有利于进一步研究Rv3872基因功能。本研究还对表达结核分枝杆菌蛋白PE35的重组卡介苗进行了鉴定,为进一步研究该重组卡介苗的免疫功能奠定了基础。     

结核分枝杆菌lhp基因原核表达载体的构建和表达

目的：构建结核分枝杆菌(MTB)lhp和基因原核表达载体并进行表达。方法：用PCR扩增MTB lhp基因，并克隆入pQE30质粒。测序正确后，再亚克隆入pET32a( )质粒，构建pQE30—CFP10和pET32a( )—CFP10重组体。结果：以重组体分别转化DH5α和BL21(DE3)菌后，经IPTG诱导，pQE30—CFP10未表达目的蛋白；而pET32a( )—CFP10则表达出Mr为20000左右重组蛋白。SDS—PAGE分析显示，IPTG诱导4h重组蛋白的表达量最高：表达蛋白以可溶性非包涵体形式存在于胞质中，表达量占全菌蛋白质的38%，用Western blot证实其具有良好的抗原性。经Ni—NTA柱纯化，获得纯度为93%的重组蛋白。结论：成功地构建原核表达载体pET32a( )—CFP10，并获得重组CFP10蛋白，为MTB重组抗原的应用奠定了基础。     

结核分枝杆菌Ag85A蛋白的原核表达、纯化和免疫反应性

目的通过原核表达获得结核分枝杆菌Ag85A蛋白。方法用PCR从结核分枝杆菌H37Rv菌株中扩增出编码Ag85A的fbpA基因,克隆入原核表达载体pProEXHTb,产生重组质粒pPro85A后,转化至大肠杆菌感受态细胞BL21并诱导大量表达。用镍纯化系统纯化重组Ag85A蛋白,用不同分枝杆菌感染的小鼠血清通过ELISA确定其免疫反应性。利用PCR技术鉴定fbpA基因在不同分枝杆菌的分布。结果32 ku的Ag85A蛋白获得高效表达和纯化。表达Ag85A蛋白的fbpA基因在结核分枝杆菌H37Rv、H37Ra、BCG、草分枝杆菌、土地分枝杆菌、耻垢分枝杆菌和次要分枝杆菌中均有表达,但在牝牛分枝杆菌中未表达。结核病患者和结核分枝杆菌毒株H37Rv感染小鼠血清所产生的抗Ag85A抗体滴度最高。结论重组Ag85A蛋白已成功表达纯化,并保留了免疫反应性。     

结核分枝杆菌Ag85B/GST融合蛋白表达载体构建及在大肠杆菌中的表达

目的 构建结核分枝杆菌Ag85B／GSF融合蛋白表达质粒，并在大肠杆菌(E．coli)中诱导表达。方法 以质粒pUC18／Ag85B为模板，用PCR法扩增结核杆菌Ag85B基因，扩增的Ag85B上游含有EcoR Ⅰ酶切位点，下游含有SalⅠ酶切位点；将Ag85B基因定向插入质粒pGEX-4T-1中，构建原核表达质粒pGEX-Ag85B并转化E．coli B121，筛选阳性重组子，限制性内切酶切鉴定和DNA序列测定，异丙基硫代半乳糖苷(IPTG)诱导表达，SDS-PAGE和Westem blot鉴定结果。结果 成功构建原核表达质粒pGEX-Ag85B并表达出Mr约56000大小的Ag85B／GSY融合蛋白，表达量占总菌体的30％。结论 为进一步进行纯化Ag85B蛋白和研究其在膀胱肿瘤治疗中的作用奠定了基础。     

Rapid and sensitive identification of Mycobacterium tuberculosis.

The fatty acid constituents of 14 species of Mycobacterium (14 isolates) and one isolate each of Corynebacterium xerosis, Nocardia asteroides, and Streptomyces albus were examined with the purpose of distinguishing Mycobacterium tuberculosis from other acid-fast bacilli. Combined thin-layer chromatography (TLC) of methyl mycolates and gas-liquid chromatography (GLC) of shorter-chain fatty acid esters provided an unequivocal identification of M. tuberculosis in a matter of 2 to 3 days. The methodology included rapid and simplified procedures for methanolysis and extraction of bacterial lipids with equally facilitated GLC and TLC analyses. These studies were performed with 0.5 to 1.0 mg of dry bacterial cells (approximately 2.5 X 10(7) CFU). When applied to 100 unknown cultures, the methodology with combined TLC-GLC correctly identified all 49 of the M. tuberculosis-Mycobacterium bovis cultures and a variety of other mycobacterium taxa. It was also interesting to note that 28 of 39 (72%) of the nontuberculous mycobacteria were correctly identified. An additional five species were tentatively identified as belonging to either of two species (Mycobacterium malmoense, Mycobacterium terrae), but in all cases, the two species belonged to the same Runyon group. All six nonmycobacterial species were differentiated from the mycobacteria studied.     

Rapid diagnostic test that uses isocitrate lyase activity for identification of Yersinia pestis.

The presence of high levels of isocitrate lyase activity in Yersinia pestis grown on blood agar base medium, as compared with low levels of this enzyme in Yersinia pseudotuberculosis and Yersinia enterocolitica, suggested that the differences in the levels of this enzyme could be used for the presumptive identification of Y. pestis. A modified, semiquantitative assay for isocitrate lyase activity is described which requires no expensive instrumentation, utilizes readily available chemicals and substrates, and requires only 20 min for completion. This test yielded positive results with all 108 isolates of Y. pestis tested and negative results with all strains of Y. pseudotuberculosis (68 isolates) and Y. enterocolitica (202 isolates) tested. Less than 2% of the approximately 1,300 non-Yersinia isolates from the family Enterobacteriaceae and none of the 93 isolates from the family Pseudomonadaceae yielded positive results. We conclude that this test provides for rapid identification of Y. pestis and should be useful in the initial screening of isolates from rodent and flea populations and in the presumptive identification of this organism from suspected cases of human plague.     

结核分枝杆菌Ag85B/IL-2-GST融合蛋白表达质粒的构建及原核表达

卡介苗（BCG）膀胱灌注是治疗表浅型膀胱肿瘤及预防其复发最有效的方法之一,BCG联合IL-2治疗膀胱肿瘤具有更好的临床疗效。无论是BCG还是IL-2在临床治疗膀胱癌均存在着剂量大、疗程长、毒副作用大等缺点。     

Evaluation of a qualitative isocitrate lyase assay for rapid presumptive identification of Yersinia pestis cultures.

Qualitative rapid tests for isocitrate lyase activity were positive for all of 1,695 Yersinia pestis cultures tested but for none of 382 cultures of other gram-negative species. The test is simple, required only commonly available, easily prepared reagents, and provided clear-cut positive or negative results within 20 min.     

Direct identification and typing of Mycobacterium tuberculosis by PCR.

We have developed a rapid PCR assay that types strains of Mycobacterium tuberculosis by generating distinct DNA fingerprints directly from primary cultures. This assay allows strain identification analogous to that achieved by the standard restriction fragment length polymorphism method, and fingerprints are obtained in less than 8 h. This assay does not require subculturing, DNA purification, restriction digestion, Southern blotting, or nucleic acid hybridization. Rapid and precise identification of M. tuberculosis strains permits immediate molecular epidemiologic studies. The assay can be converted to a computer-automated system by employing fluorescently labeled PCR primers and the Perkin-Elmer DNA sequencer so that unknown-specimen fingerprints are identified by computer comparison to a database of M. tuberculosis strain fingerprints.     

Detection and identification of Mycobacterium tuberculosis by DNA amplification.

The polymerase chain reaction (PCR) was used to identify mycobacterial DNA sequences in uncultured clinical specimens. Two oligonucleotide primers derived from the sequence of a gene that codes for the 65-kilodalton antigen of Mycobacterium tuberculosis amplified DNA from all 11 species of mycobacteria tested. Amplified DNAs of nontuberculosis mycobacteria were found to be approximately 20 to 40 bases shorter than those from M. tuberculosis and Mycobacterium bovis BCG. DNA equivalent to that present in as few as 40 M. tuberculosis cells either alone or in the presence of DNA equivalent to that in 10(6) human cells could be detected. Results from analysis of cultured bacteria and clinical specimens showed PCR was sensitive and specific both in detecting mycobacteria and in differentiating M. tuberculosis and BCG from other species of mycobacteria. The PCR method with the primers reported here may become a useful tool in the early and rapid detection of mycobacterial infections in uncultured clinical specimens.     

The role of isocitrate lyase and the glyoxylate cycle in Escherichia coli growing under glucose limitation

Escherichia coli changes its metabolism in response to environmental circumstances, and metabolic adaptations are evident in hungry bacteria growing slowly in glucose-limited chemostats. The role of isocitrate lyase (AceA) was examined in E. coli growing under glucose limitation. AceA activity was elevated in a strain-dependent manner in the commonly used E. coli K-12 laboratory strains MG1655 and MC4100, but an aceA disruption surprisingly increased fitness under glucose limitation in both strains. However, in bacteria adapted to limiting glucose in long-term chemostats, mutations outside aceA changed its role from a negative to a positive influence. These results suggest that a recently proposed pathway of central metabolism involving the glyoxylate cycle enzymes is redundant in wild-type bacteria, but may take on a beneficial role after context adaptation. Interestingly, the aceA gene sequence did not alter during prolonged selection, so mutations in unidentified genes changed the metabolic context of unaltered AceA from a negative to a positive influence in bacteria highly adapted to limiting glucose.     

Whole chromosomal DNA probes for rapid identification of Mycobacterium tuberculosis and Mycobacterium avium complex.

Whole chromosomal DNA probes were used to identify clinical isolates of Mycobacterium tuberculosis, Mycobacterium avium complex, and Mycobacterium gordonae. The probe for M. tuberculosis was prepared from Mycobacterium bovis BCG, which has been shown to be closely related to M. tuberculosis. A probe for the M. avium complex was prepared from three strains representing each of the three DNA homology groups in the M. avium complex. The probes were used in dot blot assays to identify clinical isolates of mycobacteria. The dot blot test correctly identified 57 of the 61 (93%) cultures grown on solid media, and 100% of antibiotic-treated broth-grown cells were correctly identified. Identification by dot blot required a maximum of 48 h. When the probes were tested against 63 positive BACTEC (Johnston Laboratories, Inc., Towson, Md.) cultures of clinical specimens, 59% were correctly identified. However, of the 14 BACTEC cultures that had been treated with antibiotics before being lysed, 13 (93%) were correctly identified.