结核杆菌Hsp65与人IL-2融合蛋白在耻垢杆菌表达

目的：构建能够分泌表达结核分枝杆菌热休克蛋白65（Hsp65）与人IL-2融合蛋白的重组耻垢分枝杆菌（recombinant Mycobacterium Smegmatis,rMs）。方法：用EcoRV和HindIII双酶切含Hsp65．IL-2融合基因的pPRO-hsp65-IL-2载体,回收目的基因片断Hsp65-IL-2,并将其亚克隆入同样双酶切的大肠埃希菌-分枝杆菌穿梭分泌表达载体pDE22中。重组质粒pDE22-hsp65-IL-2酶切鉴定正确后,电穿孔转化MS感受态,潮霉素抗性压力筛选阳性rMs。Westem—blot鉴定rMs培养上清蛋白中目的蛋白的表达。结果：重组pDE22-hsp65-IL-2质粒酶切后可获得约2000bp片段,与预期大小一致。Western-blot结果表明,rMs培养上清蛋白中有特异性反应条带,大小为78kD,与Hsp65-IL-2融合蛋白大小相一致。结论：成功构建了大肠埃希菌．分枝杆菌穿梭分泌表达载体pDE22-hsp65-IL-2,为该rMs的免疫学特性及抗结核分枝杆菌感染的保护效果研究奠定了基础。     

ESAT6-CFP10融合蛋白基因的克隆及其在耻垢分枝杆菌中的表达

目的:构建能表达ESAT6-CFP10融合蛋白的重组耻垢分枝杆菌疫苗。方法:以结核杆菌H37Rv基因组DNA为模板,克隆cfp10基因,将其插入到pGEM-T-easy载体后与esat6基因连接,构建含有esat6和cfp10融合基因的重组载体pGEM-e6c10。酶切消化pGEM-e6c10重组质粒,将esat6-cfp10基因亚克隆到pDE22分泌表达穿梭载体,以电穿孔方法将重组质粒转化至耻垢分枝杆菌。PCR筛选到的阳性克隆经温度诱导后,SDS-PAGE和Western印迹检测表达蛋白的正确性。结果:可表达出相对分子质量约23000的ESAT6-CFP10融合蛋白。Western印迹证明重组蛋白有较好的免疫原性。结论:获得能表达ESAT6-CFP10融合蛋白的重组耻垢分枝杆菌,为结核病的预防奠定了一定的基础。     

乙型肝炎病毒S基因与截短C基因融合的穿梭表达载体的构建

研究目的是构建HBVS基因和截短C基因融合的胞壁型和分泌型大肠杆菌和分枝杆菌(E．coli-BCG)穿梭质粒。采用PCR方法从结核分枝杆菌MTB毒株H37Rv的基因中扩增出相对分子质量为19000的抗原胞壁区及其上游调控元件基因,克隆入穿梭载体pOLYG中。以含HBV基因组的质粒pCP10序列为模板,PCR扩增获得5基因片段Sw和C基因编码氨基端的部分基因片段Ct,克隆入胞壁型穿梭表达载体pCW和分泌型穿梭表达载体pDE22。经酶切和序列测定证实,胞壁型和分泌型载体pCW-Sw-Ct和pDE22-Sw-Ct构建成功。为进一步研究含S基因和截短C基因融合的重组BCG活疫苗奠定了基础。     

表达绿色荧光蛋白的重组耻垢分枝杆菌的构建

目的 建立可表达绿色荧光蛋白的耻垢分枝杆菌,便于对耻垢分枝杆菌进行直观检测和快速定量。方法利用PCR技术从真核表达质粒pLVTH扩增获得绿色荧光蛋白的编码基因,克隆人大肠埃希菌一分枝杆菌穿梭载体pMV261,建立重组质粒pMVGFP,并经酶切鉴定证实。利用电穿孔技术将pMVGFP转化入耻垢分枝杆菌,利用卡那霉素抗性筛选重组耻垢分枝杆菌克隆,扩大培养后直接涂片,荧光显微镜镜检。结果重组质粒pMVGFP构建正确;将重组耻垢分枝杆菌在荧光显微镜下观察,证实绿色荧光蛋白在重组耻垢分枝杆菌中的表达。结论自发释放荧光的重组耻垢分枝杆菌的成功建立,为研究结核病致病机制和快速筛选化学药物等奠定了基础。     

猪白细胞介素18成熟蛋白基因的克隆与表达

目的克隆猪白细胞介素18(pIL-18)成熟蛋白基因,并在植物乳杆菌(Lb.plantarum)NC8中进行表达。方法通过RT-PCR方法从猪脾脏细胞中扩增出pIL-18成熟蛋白基因,克隆到T载体pMD18-T后测序;将阳性基因片段克隆至大肠埃希菌-乳酸菌穿梭表达载体pSIP-409构建重组表达载体pSIP-409-IL-18,进行酶切和PCR鉴定;应用电穿孔技术将其转化至Lb.plantarum NC8中,经SppIP诱导表达后,进行SDS-PAGE及Western-blot分析。结果经测序,pIL-18成熟蛋白基因核苷酸长度为579 bp,编码193个核苷酸;酶切和PCR鉴定证明成功构建了重组表达载体pSIP-409-IL-18;SDS-PAGE及Western-blot分析表明重组菌表达了18 kD的融合蛋白,该重组蛋白可以与鼠抗猪IL-18多克隆抗体反应。结论成功克隆了pIL-18成熟蛋白基因,并获得有生物活性的pIL-18重组乳酸菌,为研制开发IL-18重组乳酸菌制剂奠定基础。     

变形链球菌F-ATPase启动子荧光蛋白载体的构建及表达

目的构建由质子移位膜ATP酶(membrane-bound proton-translocating ATPase,F-ATPase)启动子启动的绿色荧光蛋白报告基因穿梭表达载体,观察其在大肠埃希菌中的表达同时鉴定表达产物。方法以变形链球菌(UA159)基因组为模板,扩增F-ATPase启动子片段,构建由F-ATPase启动子启动的绿色荧光表达载体pFgfp,酶切F-ATPase启动子及绿色荧光蛋白编码基因,连接到穿梭质粒pDL276,构建重组载体pLFgfp。结果重组质粒pLFgfp酶切及基因序列分析证实目的片段成功插入,重组载体转化后的大肠埃希菌有绿色荧光蛋白的表达,并能随着细菌传代继续表达。结论 F-ATPase启动子启动的绿色荧光蛋白穿梭表达载体pLFgfp构建成功,为研究生物膜环境中耐酸菌F-ATPase毒力因子的表达奠定基础。     

结核分枝杆菌Ag85B-Esat6-HspX融合基因真核表达载体的构建

目的构建结核分枝杆菌Ag85B-Esat6-HspX融合基因,并对其在体外真核细胞中进行表达。方法用PCR法从结核分枝杆菌H37Rv株基因组中分别扩增Ag85B、Esat6、HspX基因,插入到pUC19-T载体,序列测定正确后,将融合基因再次克隆到真核表达载体pcDNA3.1（-）。重组质粒经酶切鉴定并测序正确后,用MegaTran1.0转染293T细胞,并用Western-Blot检测目的蛋白的表达。结果 Western-blot检测到分子量大小约65 kDa的目的蛋白。结论成功地构建了结核分枝杆菌Ag85B-Esat6-HspX融合基因的真核表达载体,且该重组载体可在体外真核细胞中获得特异性的表达。     

结核杆菌活动期高表达基因Rv1776c的克隆及其在耻垢分枝杆菌中的表达

目的构建表达结核分枝杆菌Rv1776c基因的重组耻垢分支杆菌,并鉴定该基因在重组耻垢分支杆菌中的活性。方法采用PCR技术克隆结核分枝杆菌Rv1776c基因,构建大肠埃希菌-分支杆菌穿梭表达质粒pMV-Rv1776c,通过酶切和测序鉴定其正确性,用电穿孔法将重组质粒转染到耻垢分支杆菌mc^2155中。以SDS-PAGE及Western blot检测证实Rv1776c蛋白在重组耻垢分支杆菌内的表达。结果重组耻垢分支杆菌构建成功,生长曲线说明重组质粒不会影响耻垢分支杆菌的体外生长;SDSPAGE及Western blot检测证实Rv1776c在耻垢分枝杆菌内表达出相对分子量约56kD的Rv1776c蛋白。结论成功构建了Rv1776c基因的穿梭质粒pMV-Rv1776c,且该质粒在耻垢分枝杆菌内具有生物活性,为进一步研究其表达产物的功能提供基础。     

结核杆菌eis基因的克隆及其在耻垢分枝杆菌中的表达

目的:构建结核分枝杆菌eis基因的穿梭表达载体,鉴定其在重组耻垢分枝杆菌中的生物活性。方法:采用PCR技术克隆结核分枝杆菌eis基因,构建大肠杆菌-分枝杆菌穿梭表达载体pMV-eis,经酶切和测序鉴定其正确性,用电穿孔法将重组质粒转化至耻垢分枝杆菌mc²155中,采用SDS-PAGE和Western blot检测eis基因在耻垢分枝杆菌中的表达。结果:成功构建结核杆菌eis基因穿梭表达载体pMV-eis;生长曲线说明重组质粒不会影响耻垢分枝杆菌的体外生长;SDS-PAGE 和Western blot检测证实eis在耻垢分枝杆菌中可表达出相对分子量约42kDa的Eis蛋白。结论:成功构建了eis基因穿梭表达质粒pMV-eis,且该重组质粒在耻垢分枝杆菌中具有生物活性,为下一步研究表达产物Eis的功能奠定了一定基础。     

阴道毛滴虫黏附蛋白65-3基因原核表达质粒的构建及表达

质粒 pMD-18T-ap65-3 经 Xho I 和 BamH I 双酶切, 1.0% 凝胶电泳后纯化回收阴道毛滴虫黏附蛋白 65-3 基因,定向克隆至原核表达载体 pET-32a( ), 构建原核表达质粒 pET32a-ap65-3. 重组质粒转化大肠埃希菌 JM109 感受态细胞中, 筛选阳性克隆, 进行PCR﹑酶切及测序鉴定正确后, 将重组质粒 pET32a-ap65-3 转化于大肠埃希菌 BL21 中,异丙基-β-D硫代半乳糖苷 (IPTG) 诱导重组蛋白表达后利用十二烷基磺酸钠一聚丙烯酰胺凝胶电泳 (SDS-PAGE) 和免疫印迹 (Western blot) 对重组蛋白进行分析鉴定. 本实验为研究阴道毛滴虫病的致病机制及蛋白生物学功能奠定了基础.     

Polymorphisms of 20 regulatory proteins between Mycobacterium tuberculosis and Mycobacterium bovis

Mycobacterium tuberculosis and Mycobacterium bovis are responsible for tuberculosis in humans and animals, respectively. Both species are closely related and belong to the Mycobacterium tuberculosis complex (MTC). M. tuberculosis is the most ancient species from which M. bovis and other members of the MTC evolved. The genome of M. bovis is over >99.95% identical to that of M. tuberculosis but with seven deletions ranging in size from 1 to 12.7 kb. In addition, 1200 single nucleotide mutations in coding regions distinguish M. bovis from M. tuberculosis. In the present study, we assessed 75 M. tuberculosis genomes and 23 M. bovis genomes to identify non‐synonymous mutations in 202 coding sequences of regulatory genes between both species. We identified species‐specific variants in 20 regulatory proteins and confirmed differential expression of hypoxia‐related genes between M. bovis and M. tuberculosis.     

牛分支杆菌与肺结核分支杆菌基因组的比较

通过比较基因组学的方法研究发现,牛分支杆菌与肺结核杆菌基因组的同源性为99．95％,但在牛分枝杆菌基因组中有11个缺失区,大小从1kb到12．7kb,遗传信息的缺失引起牛分枝杆菌的基因组减小;牛分枝杆菌与肺结核分枝杆菌H37Rv间存在着2437个单核苷酸多态性（SNPs）,与肺结核分枝杆菌CDC1551间存在着2423个单核苷酸多态性（SNPs）,牛分支杆菌与肺结核分枝杆菌在编码细胞壁和分泌蛋白上变异程度也是巨大的。研究结果揭示了牛分支杆菌与肺结核分枝杆菌的遗传关系,为研究分支杆菌疫苗和诊断试剂提供理论依据,对牛肺结核病的防治有着非常重要的意义。     

Tuberculosis patients co-infected with Mycobacterium bovis and Mycobacterium tuberculosis in an urban area of Brazil

In this cross-sectional study, mycobacteria specimens from 189 tuberculosis (TB) patients living in an urban area in Brazil were characterised from 2008-2010 using phenotypic and molecular speciation methods (pncA gene and oxyR pseudogene analysis). Of these samples, 174 isolates simultaneously grew on Löwenstein-Jensen (LJ) and Stonebrink (SB)-containing media and presented phenotypic and molecular profiles of Mycobacterium tuberculosis, whereas 12 had molecular profiles of M. tuberculosis based on the DNA analysis of formalin-fixed paraffin wax-embedded tissue samples (paraffin blocks). One patient produced two sputum isolates, the first of which simultaneously grew on LJ and SB media and presented phenotypic and molecular profiles of M. tuberculosis, and the second of which only grew on SB media and presented phenotypic profiles of Mycobacterium bovis. One patient provided a bronchial lavage isolate, which simultaneously grew on LJ and SB media and presented phenotypic and molecular profiles of M. tuberculosis, but had molecular profiles of M. bovis from paraffin block DNA analysis, and one sample had molecular profiles of M. tuberculosis and M. bovis identified from two distinct paraffin blocks. Moreover, we found a low prevalence (1.6%) of M. bovis among these isolates, which suggests that local health service procedures likely underestimate its real frequency and that it deserves more attention from public health officials.     

Mycobacterium tuberculosis mammalian cell entry operon (mce) homologs in Mycobacterium other than tuberculosis (MOTT)

The cloned mammalian cell entry gene mce1a from Mycobacterium tuberculosis confers to non-pathogenic Escherichia coli the ability to invade and survive inside macrophages and HeLa cells. The aim of this work was to search for and characterize homologs of the four M. tuberculosis mammalian cell entry operons (mce1, mce2, mce3 and mce4) in mycobacteria other than tuberculosis (MOTT). The dot-blot and polymerase chain reaction (PCR) experiments performed on 24 clinical isolates representing 20 different mycobacterial species indicated that the mce operons were widely distributed throughout the genus Mycobacterium. BLAST search results showed the presence of mce1, mce2 and mce4 homologs in Mycobacterium bovis, Mycobacterium avium and Mycobacterium smegmatis. A homologous region for the mce3 operon was also found in M. avium and M. smegmatis. DNA and protein alignments were done to compare the M. tuberculosis mce operons and the deduced M. bovis, M. avium, and M. smegmatis homologs. The deduced proteins of M. bovis mce1, mce2 and mce4 operons had 99.6-100% homology with the respective M. tuberculosis mce proteins (MTmce). The similarity between M. avium mce proteins and the individual M. tuberculosis homologs ranged from 56.2 to 85.5%. The alignment results between M. smegmatis mce proteins and the respective MTmce proteins ranged from 58.5% to 68.5%. Primer sets were designed from the M. tuberculosis mce4a gene for amplification of 379-bp fragments. Amplification was successful in 14 strains representing 11 different mycobacterial species. The PCR fragments were sequenced from 10 strains representing eight species. Alignment of the sequenced PCR products showed that mce4a homologs are highly conserved in the genus Mycobacterium. In conclusions, the four mce operons in different mycobacterial species are generally organized in the same manner. The phylogenetic tree comparing the different mce operons showed that the mce1 operon was closely related to the mce2 operon and mce3 diverged from the other operons. The wide distribution of the mce operons in pathogenic and non-pathogenic mycobacteria implicates that the presence of these putative virulence genes is not an indicator for the pathogenicity of the bacilli. Instead, the pathogenicity of these factors might be determined by their expression.     

cAMP levels within Mycobacterium tuberculosis and Mycobacterium bovis BCG increase upon infection of macrophages

Adenosine 3',5'-cyclic monophosphate (cAMP)-mediated signal transduction is common in both prokaryotes and eukaryotes, and several bacterial pathogens modulate cAMP signaling pathways of their mammalian hosts during infection. In this study, cAMP levels associated with Mycobacterium tuberculosis and Mycobacterium bovis BCG were measured during macrophage infection. cAMP levels within both bacteria increased c . 50-fold during infection of J774.16 macrophages, relative to the cAMP levels within bacteria incubated in tissue culture media alone. cAMP levels also increased within the macrophage cytoplasm upon uptake of live, but not dead, mycobacteria. The presence of albumin in the absence of oleic acid significantly decreased cAMP secretion and production by both M. tuberculosis and M. bovis BCG. These results suggest that cAMP signaling plays a role in the interaction of tuberculosis-complex mycobacteria with macrophages during infection, and that albumin may be a physiological indicator differentiating host environments during infection.     

Mycobacterium massiliense is differentiated from Mycobacterium abscessus and Mycobacterium bolletii by erythromycin ribosome methyltransferase gene (erm) and clarithromycin susceptibility patterns

Erythromycin ribosome methyltransferase gene (erm) sequences of Mycobacterium massiliense and Mycobacterium bolletii isolates were newly investigated. Forty nine strains of M. massiliense that were analyzed in the present study had a deleted erm(41). Due to a frame‐shift mutation, large deletion, and truncated C‐terminal region, the Erm(41) of M. massiliense had only 81 amino acids encoded by 246 nucleotides. Corresponding to these findings, most of the M. massiliense isolates (89.8%) were markedly clarithromycin susceptible, but resistant strains invariably had a point mutation at the adenine (A₂₀₅₈ or A₂₀₅₉) in the peptidyltransferase region of the 23S rRNA gene, which is quite different from Mycobacterium abscessus and M. bolletii. In addition, erm(41) sequences of M. massiliense were more conserved than those of M. abscessus and M. bolletii. The results of species identification using erm(41) showed concordant results with those of multi‐locus sequence analysis (rpoB, hsp65, sodA and 16S‐23S ITS) where there were originally inconsistent results between rpoB and hsp65 sequence analysis in previous research. Therefore, erm(41) PCR that was used in the present study can be efficiently used to simply differentiate M. massiliense from M. abscessus and M. bolletii.     

Mycobacterium avium and Mycobacterium intracellulare chromatotypes defined by curvilinear gradient HPLC of mycolic acids

Seventy-nine strains of Mycobacterium avium complex bacteria (MAC), previously characterized by genetic probe analysis, were assayed using two methods of reverse phase high-performance liquid chromatography (HPLC) that employed curvilinear gradients. Although different in column length and cycle time, the methods produced equivalent results, yielding seven distinct chromatographic patterns (chromatotypes) of M. avium and M. intracellulare based on the ratio of mycolate concentrations in the late vs. the middle of three peak clusters (L:M ratio). The M. avium strains (n = 36) were assigned to chromatotypes 1 through 4 (L:M ratios less than 3), and the M. intracellulare strains (n = 25) to chromatotypes 5 through 7 (L:M ratios greater than 4). Of 18 Mycobacterium 'X' strains, seven resembled M. avium, seven others resembled M. intracellulare, and four were intermediate between M. avium and M. intracellulare.     

Expression profiles of low molecular mass heat shock proteins by Mycobacterium avium and Mycobacterium intracellulare

Closely related non-tuberculous mycobacterial species, Mycobacterium avium and Mycobacterium intracellulare, were compared for the profiles of their production of low molecular mass heat shock proteins at 45 degrees C, by performing polyacrylamide gel electrophoresis analysis of bacterial cell lysate proteins. All of the M. intracellulare but not M. avium strains potently increased the production of the 18-kDa heat shock protein, when cultured at 45 degrees C. Half of the M. intracellulare strains with high sensitivity to 45 degrees C produced not only the 18-kDa heat shock protein but also the 16-kDa heat shock protein at 45 degrees C. These findings indicate that M. avium and M. intracellulare differentially respond to 45 degrees C heat shock in terms of the production of low molecular mass heat shock proteins.     

Discrimination of Mycobacterium avium- Mycobacterium intracellulare strains by genomic DNA fingerprinting with a 16S rRNA gene probe

Abstract Ribotyping was investigated as a means of distinguishing ten different serotyped reference strains and seven epidemiologically unrelated isolates of Mycobacterium avium - Mycobacterium intracellulare using a labelled 16S rDNA probe. Thirteen restriction enzymes were screened towards an accurate discrimination of strins. Two selected restriction enzymes ( Sac I and Cla I) enabled us to classify the 17 strains into ten ribotypes with an index of discrimination of 0.897. Typeability and reproductibility of the method reached 100%. The patterns obtained exhibited polymorphism of RE fragments within and outside the 16S rRNA gene and may be useful for epidemiological studies.