共查询到20条相似文献，搜索用时 15 毫秒
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Bacterial type III protein secretion systems deliver effector proteins into eukaryotic cells in order to modulate cellular processes. Central to the function of these protein-delivery machines is their ability to recognize and secrete substrates in a defined order. Here, we describe a mechanism by which a type III secretion system from the bacterial enteropathogen Salmonella enterica serovar Typhimurium can sort its substrates before secretion. This mechanism involves a cytoplasmic sorting platform that is sequentially loaded with the appropriate secreted proteins. The sequential loading of this platform, facilitated by customized chaperones, ensures the hierarchy in type III protein secretion. Given the presence of these machines in many important pathogens, these findings can serve as the bases for the development of novel antimicrobial strategies. 相似文献
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Saeij JP Boyle JP Coller S Taylor S Sibley LD Brooke-Powell ET Ajioka JW Boothroyd JC 《Science (New York, N.Y.)》2006,314(5806):1780-1783
The majority of known Toxoplasma gondii isolates from Europe and North America belong to three clonal lines that differ dramatically in their virulence, depending on the host. To identify the responsible genes, we mapped virulence in F(1) progeny derived from crosses between type II and type III strains, which we introduced into mice. Five virulence (VIR) loci were thus identified, and for two of these, genetic complementation showed that a predicted protein kinase (ROP18 and ROP16, respectively) is the key molecule. Both are hypervariable rhoptry proteins that are secreted into the host cell upon invasion. These results suggest that secreted kinases unique to the Apicomplexa are crucial in the host-pathogen interaction. 相似文献
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A secreted serine-threonine kinase determines virulence in the eukaryotic pathogen Toxoplasma gondii
Taylor S Barragan A Su C Fux B Fentress SJ Tang K Beatty WL Hajj HE Jerome M Behnke MS White M Wootton JC Sibley LD 《Science (New York, N.Y.)》2006,314(5806):1776-1780
Toxoplasma gondii strains differ dramatically in virulence despite being genetically very similar. Genetic mapping revealed two closely adjacent quantitative trait loci on parasite chromosome VIIa that control the extreme virulence of the type I lineage. Positional cloning identified the candidate virulence gene ROP18, a highly polymorphic serine-threonine kinase that was secreted into the host cell during parasite invasion. Transfection of the virulent ROP18 allele into a nonpathogenic type III strain increased growth and enhanced mortality by 4 to 5 logs. These attributes of ROP18 required kinase activity, which revealed that secretion of effectors is a major component of parasite virulence. 相似文献
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Bioinformatic analysis and functional characterization of the cfem proteins in maize anthracnose fungus Colletotrichum graminicola 
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下载免费PDF全文 GONG An-dong JING Zhong-ying ZHANG Kai TAN Qing-qun WANG Guo-liang LIU Wen-de 《农业科学学报》2020,19(2):541-550
Fungal secreted proteins that contain the Common in Fungal Extracellular Membrane(CFEM) domain are important for pathogenicity. The hemibiotrophic fungus Colletotrichum graminicola causes the serious anthracnose disease of maize. In this study, we identified 24 CgCFEM proteins in the genome of C. graminicola. Phylogenic analysis revealed that these 24 proteins(CgCFEM1–24) can be divided into 2 clades based on the presence of the trans-membrane domain. Sequence alignment analysis indicated that the amino acids of the CFEM domain are highly conserved and contain 8 spaced cysteines, with the exception that CgCFEM1 and CgCFEM24 lack 1 and 2 cysteines, respectively. Ten CgCFEM proteins with a signal peptide and without the trans-membrane domain were considered as candidate effectors and, thus were selected for structural prediction and functional analyses. The CFEM domain in the candidate effectors can form a helical-basket structure homologous to the Csa2 protein in Candida albicans, which is responsible for haem acquisition and pathogenicity. Subcellular localization analysis revealed that these effectors accumulate in the cell membrane, nucleus, and cytosolic bodies. Additionally, 5 effectors, CgCFEM6, 7, 8, 9 and 15, can suppress the BAX-induced programmed cell death in Nicotiana benthamiana with or without the signal peptide. These results demonstrate that these 10 CgCFEM candidate effectors with different structures and subcellular localizations in host cells may play important roles during the pathogenic processes on maize plants. 相似文献
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Salmonella enterica causes a variety of diseases, including gastroenteritis and typhoid fever. The success of this pathogen depends on its capacity to proliferate within host cells in a membrane-bound compartment. We found that the Salmonella-containing vacuole recruited the plus-end-directed motor kinesin. Bacterial effector proteins translocated into the host cell by a type III secretion system antagonistically regulated this event. Among these effectors, SifA targeted SKIP, a host protein that down-regulated the recruitment of kinesin on the bacterial vacuole and, in turn, controlled vacuolar membrane dynamics. 相似文献
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Schirawski J Mannhaupt G Münch K Brefort T Schipper K Doehlemann G Di Stasio M Rössel N Mendoza-Mendoza A Pester D Müller O Winterberg B Meyer E Ghareeb H Wollenberg T Münsterkötter M Wong P Walter M Stukenbrock E Güldener U Kahmann R 《Science (New York, N.Y.)》2010,330(6010):1546-1548
Biotrophic pathogens, such as the related maize pathogenic fungi Ustilago maydis and Sporisorium reilianum, establish an intimate relationship with their hosts by secreting protein effectors. Because secreted effectors interacting with plant proteins should rapidly evolve, we identified variable genomic regions by sequencing the genome of S. reilianum and comparing it with the U. maydis genome. We detected 43 regions of low sequence conservation in otherwise well-conserved syntenic genomes. These regions primarily encode secreted effectors and include previously identified virulence clusters. By deletion analysis in U. maydis, we demonstrate a role in virulence for four previously unknown diversity regions. This highlights the power of comparative genomics of closely related species for identification of virulence determinants. 相似文献
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基于全基因组序列预测里氏木霉QM6a的分泌蛋白 总被引：1，自引：0，他引：1
里氏木霉(Trichoderma reesei)QM6a为重要的产纤维素酶工业生产菌株,为明确其内存在的分泌蛋白,对该菌分泌蛋白进行预测,并明确其特征。利用SignalP、ProtComp等5个软件对该菌中9 143条蛋白质序列进行分泌蛋白预测,并对上述分泌蛋白的氨基酸大小分布情况、信号肽长度及其切割位点等性质进行分析。里氏木霉中含有分泌蛋白356个,其氨基酸长度、信号肽长度与其他植物病原菌不同;信号肽切割位点属于A-X-A类型,与其他已经报道的植物病原真菌、细菌以及卵菌中分泌蛋白信号肽切割位点一致。通过上述生物信息学分析方法有效地实现了里氏木霉分泌蛋白的预测,也证明了分泌蛋白的信号肽切割位点具有物种保守性特点。 相似文献
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Mueller CA Broz P Müller SA Ringler P Erne-Brand F Sorg I Kuhn M Engel A Cornelis GR 《Science (New York, N.Y.)》2005,310(5748):674-676
Many pathogenic bacteria use injectisomes to deliver effector proteins into host cells through type III secretion. Injectisomes consist of a basal body embedded in the bacterial membranes and a needle. In Yersinia, translocation of effectors requires the YopB and YopD proteins, which form a pore in the target cell membrane, and the LcrV protein, which assists the assembly of the pore. Here we report that LcrV forms a distinct structure at the tip of the needle, the tip complex. This unique localization of LcrV may explain its crucial role in the translocation process and its efficacy as the main protective antigen against plague. 相似文献
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白粉菌通过在植物细胞内形成吸器,产生大量的效应蛋白,从而实现在寄主细胞内的侵染。前期有研究人员对Oidium heveae进行基因组和转录组测序分析,预测出133个潜在的效应蛋白。笔者克隆了其中的一个基因OhEP2 (Oidium heveae Effector Protein 2),并构建了OhEF 2基因在拟南芥Col-0背景下的过表达转基因植株。通过接种发现,过量表达OhEF 2可以明显促进拟南芥对橡胶树白粉菌的感病性,但不能提高假单胞菌DC 3000的毒性功能,表明OhEF 2可能只在白粉菌侵染的过程中发挥作用。进一步研究发现,OhEF 2显著降低了橡胶树白粉菌在拟南芥上激发的胼胝体沉积和PR1 (Pathogen-Related Gene1)基因表达,这为进一步研究效应蛋白OhEF 2在植物体内的毒性作用机理奠定了基础。 相似文献
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Signatures of adaptation to obligate biotrophy in the Hyaloperonospora arabidopsidis genome 总被引：2，自引：0，他引：2
Baxter L Tripathy S Ishaque N Boot N Cabral A Kemen E Thines M Ah-Fong A Anderson R Badejoko W Bittner-Eddy P Boore JL Chibucos MC Coates M Dehal P Delehaunty K Dong S Downton P Dumas B Fabro G Fronick C Fuerstenberg SI Fulton L Gaulin E Govers F Hughes L Humphray S Jiang RH Judelson H Kamoun S Kyung K Meijer H Minx P Morris P Nelson J Phuntumart V Qutob D Rehmany A Rougon-Cardoso A Ryden P Torto-Alalibo T Studholme D Wang Y Win J Wood J Clifton SW Rogers J Van den Ackerveken G Jones JD 《Science (New York, N.Y.)》2010,330(6010):1549-1551
Many oomycete and fungal plant pathogens are obligate biotrophs, which extract nutrients only from living plant tissue and cannot grow apart from their hosts. Although these pathogens cause substantial crop losses, little is known about the molecular basis or evolution of obligate biotrophy. Here, we report the genome sequence of the oomycete Hyaloperonospora arabidopsidis (Hpa), an obligate biotroph and natural pathogen of Arabidopsis thaliana. In comparison with genomes of related, hemibiotrophic Phytophthora species, the Hpa genome exhibits dramatic reductions in genes encoding (i) RXLR effectors and other secreted pathogenicity proteins, (ii) enzymes for assimilation of inorganic nitrogen and sulfur, and (iii) proteins associated with zoospore formation and motility. These attributes comprise a genomic signature of evolution toward obligate biotrophy. 相似文献
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为了更好地明确褐环乳牛肝菌分泌蛋白的功能,基于前期所获得327个分泌蛋白序列,对其理化性质进行分析。结果表明,69.72%的分泌蛋白理论等电点小于6.0,属于酸性蛋白,同时,利用随机数生成软件对上述不同理论等电点类别的分泌蛋白进行10%抽样分析,明确33个不同理论等电点类别的分泌蛋白(包括23个酸性蛋白、4个中性蛋白、6个碱性蛋白)的分子质量、分子式、原子数量、半衰期、不稳定性系数、脂肪族氨基酸指数、总平均亲水性等理化性质,其中14个分泌蛋白为稳定性蛋白,14个分泌蛋白为亲水性蛋白。 相似文献
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丁香假单胞菌产生的荧光色素是一种具有毒性功能的致病性因子,也是细菌鉴定和分类的重要依据。测定了基本培养基不同组分的浓度对丁香假单胞菌荧光色素产生能力的影响,并比较了几种金属离子螯合剂对恢复丁香假单胞菌荧光物质合成能力以及细菌生长能力的影响,旨在找到恢复丁香假单胞菌在常规培养基上合成荧光色素的方法。结果如下:①丁香假单胞菌荧光色素的合成能力主要受培养基中铁离子浓度的影响,而与眎蛋白胨,以及K2HPO4、MgSO4的浓度均无关;② 0.05 g/L的螯合剂8-羟基喹啉可使丧失荧光物质合成能力的丁香假单胞菌恢复产生荧光,恢复的荧光物质合成可以被铁盐（FeCl3）逆转;但同时8-羟基喹啉对细菌生长也有一定的抑制作用;③其他金属离子螯合剂,如柠檬酸(C6H8O7·H2O)、酒石酸钠(Na2C4H4O6)、磷酸三钠(Na3PO4)和乙二胺四乙酸二钠(EDTA-Na2),均不能恢复丁香假单胞菌产荧光色素。该结果表明在KB培养基中添加螯合剂8-羟基喹啉（0.05 g/L）可以使丁香假单胞菌恢复荧光物质的合成能力。 相似文献
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The genomes of the barley, Arabidopsis and pea powdery mildew are significantly larger than those of related fungi. This is due to an extraordinary expansion of retro-trasposons that are evident as repetitive elements in the sequence. The protein coding genes are fewer than expected due to an overall reduction in the size of gene families, a reduction in the number of paralogs and because of the loss of certain metabolic pathways. Many of these changes have also been observed in the genomes of other taxonomically unrelated obligate biotrophic pathogens. The only group of genes that bucks the trend of gene loss, are those encoding small secreted proteins that bear the hall marks of effectors. 相似文献
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利用聚丙稀酰胺电泳技术首次对丁香假单胞菌中6个致病变种全细胞蛋白电泳,发现同一致病变种内菌株蛋白条带一致,不同致病变种之间存在差异.以往对丁香假单胞菌中致病变种的鉴定方法主要是根据致病性的差异,结合营养筛选和血清学方法来进行.对丁香假单胞菌的6个致病变种的全细胞蛋白分析表明:全细胞蛋白质电泳能成功地鉴定到致病变种. 相似文献
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Srikanth CV Wall DM Maldonado-Contreras A Shi HN Zhou D Demma Z Mumy KL McCormick BA 《Science (New York, N.Y.)》2010,330(6002):390-393
The enteric pathogen Salmonella enterica serovar Typhimurium causes food poisoning resulting in gastroenteritis. The S. Typhimurium effector Salmonella invasion protein A (SipA) promotes gastroenteritis by functional motifs that trigger either mechanisms of inflammation or bacterial entry. During infection of intestinal epithelial cells, SipA was found to be responsible for the early activation of caspase-3, an enzyme that is required for SipA cleavage at a specific recognition motif that divided the protein into its two functional domains and activated SipA in a manner necessary for pathogenicity. Other caspase-3 cleavage sites identified in S. Typhimurium appeared to be restricted to secreted effector proteins, which indicates that this may be a general strategy used by this pathogen for processing of its secreted effectors. 相似文献
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【目的】可可毛色二孢（Lasiodiplodia theobromae）是一种世界性分布的重要植物病原真菌,可引起严重的葡萄溃疡病（Botryosphaeria dieback）,影响果木品质并造成巨大的经济损失。本研究预测并分析可可毛色二孢基因组范围内的分泌蛋白,并明确其基本特征,为该病菌分泌蛋白致病机理的研究打下基础。【方法】依据已公布的可可毛色二孢全基因组序列,利用信号肽预测软件SignalP v5.0、跨膜结构分析软件TMHMM v2.0、细胞器定位分析软件ProtComp v9.0、GPI锚定预测软件big-PI Fungal Predictor和亚细胞器定位分析软件TargetP v2.0生物信息学软件对该菌中的典型分泌蛋白进行筛选。对分泌蛋白N端信号肽的长度、氨基酸使用频率及其切割位点进行统计分析。依据蛋白序列的同源性,应用BLASTP程序对分泌组蛋白进行功能注释分析,预测其生物学功能。采用蔗糖酶缺陷的酵母分泌系统,对所选分泌蛋白的信号肽进行活性检测。利用qRT-PCR方法检测所选分泌蛋白基因在可可毛色二孢侵染葡萄中的表达情况。【结果】在可可毛色二孢全基因组编码蛋白中共筛选获得552个潜在的具有典型信号肽的分泌蛋白,占全基因组预测蛋白总数的4.3%,其编码蛋白长度集中于101—400 aa。信号肽统计分析表明,其信号肽长度以18—20 aa的序列最为集中,信号肽长度为20 aa的蛋白数量最多。信号肽中使用频率最高的氨基酸为丙氨酸;非极性、疏水的氨基酸使用频率最高,占氨基酸总数的60.2%。其信号肽的-3至-1位置上的氨基酸相对保守,切割位点属于A-X-A类型,可被Sp I型信号肽酶识别并切割。336个分泌蛋白具有功能注释,其功能较多集中于细胞壁降解有关的酶类以及致病相关蛋白,并且这些蛋白在分子量、等电点、脂肪族氨基酸指数等方面均存在差异。通过蔗糖酶缺陷的酵母分泌系统证实,挑选的9个分泌蛋白信号肽均具有分泌活性。qRT-PCR检测结果表明,所选分泌蛋白基因在该病菌侵染初期的表达发生变化。【结论】利用生物信息学分析技术从可可毛色二孢全基因组中共预测获得552个经典分泌蛋白。其信号肽氨基酸长度分布广泛,氨基酸组成中非极性、疏水的氨基酸使用频率最高。功能注释主要集中在细胞壁组分降解相关的酶类、致病侵染相关的坏死诱导相关蛋白以及几丁质结合蛋白等。 相似文献
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三七细菌性叶斑病病原菌鉴定 总被引：1，自引：0，他引：1
[目的]对引起三七细菌性叶宽病的病原菌进行系统鉴定。[方法]以2011及2012年在云南文山及石林县的三七苗圃采集的三七细菌性叶斑病病株为材料,采用柯赫氏法则,检测分离菌株致病性并重新分离得到病原菌。通过病菌形态观察、致病性测定、16SrD—NA序列分析及生理生化特性分析（Biolog系统）对其进行鉴定。[结果]确定三七细菌性叶斑病病原菌为丁香假单胞菌丁香致病变种（Pseudomonas syringae pv．syringae）。[结论]该研究为三七细菌性叶瘫病菌详细鉴定的国内首报。 相似文献
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