共查询到18条相似文献,搜索用时 171 毫秒
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S层(Slayer)是由单一的蛋白或糖蛋白组成的薄层晶状结构,它广泛存在于古细菌和真细菌细胞的最外表面,可包裹整个细胞。S层在结构化学、形态学、遗传学以及物理化学等方面具有独特的性质,使之在生物技术、分子纳米技术和仿生学等领域蕴藏着广泛的应用潜力。近年来,随着微生物表 相似文献
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S-层蛋白质的功能和应用 总被引:2,自引:0,他引:2
400多种古细菌和细菌有S-层蛋白质,该蛋白质能在菌体表面自装配为规则晶格的单分子表面层(S-层),与菌体以非共价方式连接。S-层作为菌体面对环境的最外层屏障,具有保护、分子筛、维持菌体形状、细胞识别和黏附、毒力因子等功能,是菌体适应周围环境的重要结构。随着遗传、结构、装配和功能等方面研究的逐渐深入,人们意识到了S-层蛋白质潜在的应用价值。其基因的可操作性,独特的自装配特性及其单分子晶体层的结构都很有应用前景,目前已经应用在异源蛋白质的分泌性表达、表面展示和纳米科技等方面。 相似文献
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利用苏云金芽胞杆菌细胞表面展示系统表达禽流感病毒NP蛋白 总被引:1,自引:0,他引:1
首次利用苏云金芽胞杆菌(Bacillus thuringiensis,Bt)S-层蛋白CTC表面展示系统研究在Bt细胞表面展示禽流感病毒NP蛋白的可行性和最佳方案,为研制能常温长期保藏和运输的禽用口服疫苗奠定基础。用全长np基因或部分np基因(npp)代替S-层蛋白ctc基因的3′-端或中部,构建了4个重组质粒pSNP(含ctc-np)、pCSA-SNP(csa-ctc-np)、pCTC-NPP(ctc-npp)和pCSNPP(csa-ctc-npp)。将重组质粒分别电转化入Bt受体菌株BMB171中,获得了5个重组菌株BN、BCN、C-S、BCCN和CN。用5个重组菌株的营养细胞做玻片凝集试验,结果显示5个重组菌株均成功地在细胞表面展示了NP蛋白。用5个重组菌株的营养细胞免疫小鼠,ELISA测定血清抗体效价,结果显示5个重组菌株均具有免疫原性,其中重组菌株CN的免疫原性最高,其含融合基因csa-ctc-npp,证明该种融合基因的构建方式最佳。这为利用S-层蛋白CTC表面展示系统构建展示其它禽类病原体抗原的重组菌株以研制禽用热稳定性口服疫苗奠定了基础。 相似文献
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噬菌体表面展示肽库技术是近年来发展起来的用丝状噬菌体展示外源肽的一项新技术,被广泛应用于分子识别的各个领域。本文就该技术在病毒受体、病毒抗原表位、病毒抗体以及病毒疫苗和病毒性疾病的诊断等央电荷和一简要概述。 相似文献
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唾液富组氨酸蛋白(histidine-rich protein, HRPs)是由人类和高等灵长动物的腮腺、下颌下腺、舌下腺分泌到唾液中的碱性小分子多肽,分子量为4 kD左右,其氨基酸序列富含组氨酸,分子表面带有正电荷和稳定的α螺旋结构.唾液富组氨酸蛋白具有广谱抗菌性,对革兰氏阴性菌、革兰氏阳性菌及真菌都有杀伤作用,其抗菌机制是作用线粒体呼吸通路,诱发ATP的释放.此外,唾液富组氨酸蛋白具有促进伤口愈合的能力,其作用机制与细胞内信号调节激酶1/2通路相关.同时,它也具有金属离子结合能力、机体免疫调节能力,其作用机制与分子表面本身结构特点和阻滞下游信号通路相关.唾液富组氨酸蛋白是一种天然的功能性蛋白质,有望应用在相关疾病的治疗上,本文对唾液富组氨酸蛋白的结构特点、功能机制、应用前景作一简要论述,为后续功能蛋白质的研发和应用奠定了理论基础. 相似文献
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苏云金芽胞杆菌CTC菌株的S-层蛋白可以形成伴胞晶体 总被引:2,自引:1,他引:1
苏云金芽胞杆菌(Bacillus thuringiensis)CTC菌株产生卵圆形伴胞晶体,晶体蛋白分子量为100kD;透射电子显微镜观察结果表明该菌株有S—层结构,而且在母细胞内可以形成伴胞晶体和S—层的初体结构;其蛋白基因导入苏云金芽胞杆菌无晶体突变株BMB171后,扫描电子显微镜观察结果表明转化子能形成晶体,而其形状与CTC菌株的相同;转化子晶体蛋白的分子量大小也与CTC菌株的相同,为100kD。以上实验结果结合以前晶体蛋白N—末端测序和基因核苦酸序列,表明苏云金芽胞杆菌CTC菌株的S—层蛋白可以形成伴胞晶体。 相似文献
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Gang Guo Lei Zhang Zhou Zhou Qiqi Ma Jianping Liu Chenguang Zhu Lei Zhu Ziniu Yu & Ming Sun 《FEMS microbiology letters》2008,282(1):1-7
Bacillus thuringiensis produces various groups of active proteins, such as Cyt, Vip and Parasporin, in addition to the Cry protein. In this study we show S-layer proteins to be a new group of parasporal inclusions of B. thuringiensis . The S-layer consists of a two-dimensional lattice structure and is the outermost component of many archaeobacteria and eubacteria. The parasporal inclusion of B. thuringiensis strain CTC was found to be not a typical crystal protein encoded by the cry gene, but a proteinaceous inclusion encoded by the S-layer gene. Furthermore, the CTC-like strains (with their parasporal inclusions coded by the S-layer gene) are widely distributed and accounted for 25.4% of the B. thuringiensis strains tested. These strains constitue a new group of parasporal inclusions encoded by the S-layer gene of B. thuringiensis and shed new light on B. thuringiensis nontoxic strains. 相似文献
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We screened four B. thuringiensis strains whose parasporal inclusions contained the S-layer protein (SLP), and cloned two slp genes from each strain. Phylogenetic analysis indicated these SLPs could be divided into two groups, SLP1s and SLP2s. To confirm whether SLPs were present in the S-layer or as a parasporal inclusion, strains CTC and BMB1152 were chosen for further study. Western blots with whole-cell associated proteins from strains CTC and BMB1152 in the vegetative phase showed that SLP1s and SLP2s were constituents of the S-layer. Immunofluorescence utilizing spore-inclusion mixtures of strains CTC and BMB1152 in the sporulation phase showed that SLP1s and SLP2s were also constituents of parasporal inclusions. When heterogeneously expressed in the crystal negative strain BMB171, four SLPs from strains CTC and BMB1152 could also form parasporal inclusions. This temporal and spatial expression is not an occasional phenomenon but ubiquitous in B. thuringiensis strains. 相似文献
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类似S-层蛋白的苏云金芽胞杆菌伴胞晶体蛋白基因的克隆 总被引:9,自引:5,他引:4
芽胞杆菌CTC菌被鉴定为苏云金芽胞杆菌,鞭毛血清型H2,幕虫亚种;产生卵圆形伴胞晶体,伴胞晶体蛋白为100kD;测定了该蛋白 N-末端序列,该序列与炭疽芽胞杆菌的细胞表面S-层蛋白具92-93%相似性,根据Southern杂交制作了该晶体蛋白基因ctc所在位置的限制性酶切图谱,分别克隆了该基因5’和3’端所在2.9kb XbaI片段和3.1kb Cla I DNA片段,彼此间具0.6kb重叠,通过拼接获得含完整ctc基因的克隆,含该基因的大肠杆菌与表达S-层蛋白的大肠杆菌具相似生长特征,初步表明CTC菌株的伴胞晶体由细胞表面S-层蛋白组成,苏云金芽胞杆菌区别于蜡状芽胞杆菌和炭疽芽胞杆菌的唯一标准是能形成伴胞晶体,由于S-层是细胞表面的结构成分,本文对CTC菌株鉴定为苏云金芽胞杆菌以及伴胞晶体作为苏云金芽胞杆菌鉴别的唯一标准提出了质疑。 相似文献
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The S-layer protein CTC surface display system of Bacillus thuringiensis was used to test the possibility of displaying avian influenza virus nucleoprotein (NP) on the cell surface of B. thuringiensis. By fusing np with the anchoring motif of ctc, four recombinant plasmids were constructed. They harbored fusion gene ctc-np, csa-ctc-np (csa representing csaAB operon, very important in anchoring S-layer protein on cell surface), ctc-npp (npp representing the part fragment of np), and csa-ctc-npp, respectively. Five recombinant strains were obtained by transferring recombinant plasmids to B. thuringiensis plasmid-free derivative strain BMB171. The vegetative cells of five strains were used as agglutinogens for slide agglutination
assays. The assays showed recombinant NP proteins successfully displayed on the cell surface of five strains. After immunization
of chickens with spores by oral route, all five strains elicited a humoral response to NP and exhibited immunogenicity as
indicated by enzyme-linked immunosorbent assay (ELISA). ELISA also showed that one of five strains, CN (bearing csa-ctc-npp), exhibited the highest immunogenicity among five strains, which suggested that the best way of constructing ctc fusion gene was the csa-ctc-npp. The strategy developed in this study suggests the possibility of generating a heat-stable and oral veterinary vaccine with
B. thuringiensis surface display system. 相似文献
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Distribution of S-layers on the surface of Bacillus cereus strains: phylogenetic origin and ecological pressure 总被引:2,自引:0,他引:2
Mignot T Denis B Couture-Tosi E Kolstø AB Mock M Fouet A 《Environmental microbiology》2001,3(8):493-501
Bacillus anthracis , Bacillus cereus and Bacillus thuringiensis have been described as members of the Bacillus cereus group but are, in fact, one species. B. anthracis is a mammal pathogen, B. thuringiensis an entomopathogen and B. cereus a ubiquitous soil bacterium and an occasional human pathogen. In two clinical isolates of B. cereus , in some B. thuringiensis strains and in B. anthracis , an S-layer has been described. We investigated how the S-layer is distributed in B. cereus , and whether phylogeny or ecology could explain its presence on the surface of some but not all strains. We first developed a simple biochemical assay to test for the presence of the S-layer. We then used the assay with 51 strains of known genetic relationship: 26 genetically diverse B. cereus and 25 non- B. anthracis of the B. anthracis cluster. When present, the genetic organization of the S-layer locus was analysed further. It was identical in B. cereus and B. anthracis . Nineteen strains harboured an S-layer, 16 of which belonged to the B. anthracis cluster. All 19 were B. cereus clinical isolates or B. thuringiensis , except for one soil and one dairy strain. These findings suggest a common phylogenetic origin for the S-layer at the surface of B. cereus strains and, presumably, ecological pressure on its maintenance. 相似文献
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Zhang L Ruan L Hu C Wu H Chen S Yu Z Sun M 《Applied microbiology and biotechnology》2007,76(3):667-675
Two genes, ctc and ctc2, responsible for surface layer (S-layer) protein synthesis in Bacillus thuringiensis CTC, were mutated and resulted in B. thuringiensis Tr5. To synthesize and express the N-acyl-homoserine lactonase (AHL-lactonase) in the extracellular space of B. thuringiensis, the aiiA
4Q7
gene (an AHL-lactonase gene from B. thuringiensis 4Q7), which confers the ability to inhibit plant soft rot disease in B. thuringiensis 4Q7, was fused with the upstream sequence of the ctc gene, which in turn is essential for S-layer protein secretion and anchoring on the cell surface. The resulting fusion gene,
slh-aiiA, was expressed in B. thuringiensis Tr5 to avoid competition for the extracellular space with the native S-layer protein. Our results indicate that B. thuringiensis Tr5 containing the fusion gene slh-aiiA displayed high extracellular AHL-degrading activity. When compared with wild-type B. thuringiensis strains, the ability of the constructed strain to inhibit soft rot disease caused by Erwinia carotovora SCG1 was markedly increased. These findings provide evidence for a significant advance in our ability to inhibit soft rot
disease caused by E. carotovora. 相似文献
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Yan-chun Wang Na Jiang De-wen Zhan Hao-xia Tao Sheng-ling Yuan Peng Wang Ling-chun Wang Zhao-shan Zhang Chun-jie Liu 《World journal of microbiology & biotechnology》2011,27(11):2575-2581
Extracellular antigen 1 (EA1), a major component of the Bacillus anthracis surface layer (S-layer), was used as a fusion partner for the expression of heterologous antigen. A recombinant B. anthracis strain was constructed by integrating a translational fusion harboring the DNA fragments encoding the cell wall–targeting
domain of the S-layer protein EA1 and the 20-kDa N-terminal fragment of anthrax protective antigen (PA20) into the chromosome.
A thermosensitive plasmid expressing Cre recombinase was introduced at a permissive temperature to remove the antibiotic marker.
Cre recombinase action at the loxP sites excised the spectinomycin resistance cassette. The final derivative strains were
analyzed by sodium dodecyl sulfate–polyacrylamide gel electrophoresis, Western blot analysis, and immunofluorescence analysis.
PA20 was successfully expressed on the S-layer of the recombinant antibiotic marker-free strain. Guinea pigs were immunized
with the attenuated recombinant B. anthracis strain, and the bacilli elicited a humoral response to PA20. This antibiotic marker-free strain and the correlative experiment
method may have potential applications for the generation of a live attenuated anthrax vaccine. 相似文献