scholarly journals Complete Genome Sequence of Uropathogenic Proteus mirabilis, a Master of both Adherence and Motility

2008 ◽  
Vol 190 (11) ◽  
pp. 4027-4037 ◽  
Author(s):  
Melanie M. Pearson ◽  
Mohammed Sebaihia ◽  
Carol Churcher ◽  
Michael A. Quail ◽  
Aswin S. Seshasayee ◽  
...  
Keyword(s):  
Genome Sequence ◽  
Proteus Mirabilis ◽  
Complete Genome Sequence ◽  
Type Iii Secretion ◽  
Complete Genome ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Type Iii ◽  
Genes Encoding

ABSTRACT The gram-negative enteric bacterium Proteus mirabilis is a frequent cause of urinary tract infections in individuals with long-term indwelling catheters or with complicated urinary tracts (e.g., due to spinal cord injury or anatomic abnormality). P. mirabilis bacteriuria may lead to acute pyelonephritis, fever, and bacteremia. Most notoriously, this pathogen uses urease to catalyze the formation of kidney and bladder stones or to encrust or obstruct indwelling urinary catheters. Here we report the complete genome sequence of P. mirabilis HI4320, a representative strain cultured in our laboratory from the urine of a nursing home patient with a long-term (≥30 days) indwelling urinary catheter. The genome is 4.063 Mb long and has a G+C content of 38.88%. There is a single plasmid consisting of 36,289 nucleotides. Annotation of the genome identified 3,685 coding sequences and seven rRNA loci. Analysis of the sequence confirmed the presence of previously identified virulence determinants, as well as a contiguous 54-kb flagellar regulon and 17 types of fimbriae. Genes encoding a potential type III secretion system were identified on a low-G+C-content genomic island containing 24 intact genes that appear to encode all components necessary to assemble a type III secretion system needle complex. In addition, the P. mirabilis HI4320 genome possesses four tandem copies of the zapE metalloprotease gene, genes encoding six putative autotransporters, an extension of the atf fimbrial operon to six genes, including an mrpJ homolog, and genes encoding at least five iron uptake mechanisms, two potential type IV secretion systems, and 16 two-component regulators.

scholarly journals Expression of the Bradyrhizobium japonicum Type III Secretion System in Legume Nodules and Analysis of the Associated tts box Promoter

2008 ◽  
Vol 21 (8) ◽  
pp. 1087-1093 ◽  
Author(s):  
Susanne Zehner ◽  
Grit Schober ◽  
Mandy Wenzel ◽  
Kathrin Lang ◽  
Michael Göttfert
Keyword(s):  
Type Iii Secretion ◽  
Bradyrhizobium Japonicum ◽  
Response Regulator ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Symbiotic Efficiency ◽  
Type Iii ◽  
Genes Encoding ◽  
Transcriptional Start Sites ◽  
Type Three Secretion

In Bradyrhizobium japonicum, as in some other rhizobia, symbiotic efficiency is influenced by a type III secretion system (T3SS). Most genes encoding the transport machinery and secreted proteins are preceded by a conserved 30-bp motif, the type-three secretion (tts) box. In this study, we found that regions downstream of 34 tts boxes are transcribed. For nopB, nopL, and gunA2, the transcriptional start sites were found to be 12, 11, and 10 bp downstream of their tts boxes, respectively. The deletion of this motif or modification of two or more conserved residues strongly reduced expression of nopB. This indicates that the tts box is an essential promoter element. Data obtained with lacZ reporter gene fusions of five genes preceded by a tts box (gunA2, nopB, rhcV, nopL, and blr1806) revealed that they are expressed in 4-week-old nodules of Macroptilium atropurpureum. These data suggest that the T3SS is active in mature nitrogen-fixing nodules. The two-component response regulator TtsI is required for the expression of rhcV, nopL, and blr1806 in bacteroids. Staining of inoculated roots showed that nopB is also expressed in early infection stages.

Evaluation of biofilm production and characterization of genes encoding type III secretion system among Pseudomonas aeruginosa isolated from burn patients

Burns ◽  
2012 ◽  
Vol 38 (8) ◽  
pp. 1192-1197 ◽  
Author(s):  
Fereshteh Jabalameli ◽  
Akbar Mirsalehian ◽  
Babak Khoramian ◽  
Marzieh Aligholi ◽  
Seyed Sajjad Khoramrooz ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Type Iii Secretion ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Burn Patients ◽  
Type Iii ◽  
Biofilm Production ◽  
Genes Encoding

scholarly journals Chlamydial Type III Secretion System Is Encoded on Ten Operons Preceded by Sigma 70-Like Promoter Elements

2006 ◽  
Vol 189 (1) ◽  
pp. 198-206 ◽  
Author(s):  
P. Scott Hefty ◽  
Richard S. Stephens
Keyword(s):  
Type Iii Secretion ◽  
Transcriptional Start Site ◽  
Type Iii Secretion System ◽  
Regulatory Elements ◽  
Secretion System ◽  
Secretion Systems ◽  
Promoter Elements ◽  
Type Iii ◽  
Type Iii Secretion Systems ◽  
Genes Encoding

ABSTRACT Many gram-negative bacterial pathogens employ type III secretion systems for infectious processes. Chlamydiae are obligate intracellular bacteria that encode a conserved type III secretion system that is likely requisite for growth. Typically, genes encoding type III secretion systems are located in a single locus; however, for chlamydiae these genes are scattered throughout the genome. Little is known regarding the gene regulatory mechanisms for this essential virulence determinant. To facilitate identification of cis-acting transcriptional regulatory elements, the operon structure was determined. This analysis revealed 10 operons that contained 37 genes associated with the type III secretion system. Linkage within these operons suggests a role in type III secretion for each of these genes, including 13 genes encoding proteins with unknown function. The transcriptional start site for each operon was determined. In conjunction with promoter activity assays, this analysis revealed that the type III secretion system operons encode σ70-like promoter elements. Transcriptional initiation by a sigma factor responsible for constitutive gene expression indicates that undefined activators or repressors regulate developmental stage-specific expression of chlamydial type III secretion system genes.

scholarly journals Mutations in Salmonella Pathogenicity Island 2 (SPI2) Genes Affecting Transcription of SPI1 Genes and Resistance to Antimicrobial Agents

1998 ◽  
Vol 180 (18) ◽  
pp. 4775-4780 ◽  
Author(s):  
Jörg Deiwick ◽  
Thomas Nikolaus ◽  
Jaqueline E. Shea ◽  
Colin Gleeson ◽  
David W. Holden ◽  
...  
Keyword(s):  
Type Iii Secretion ◽  
Antimicrobial Agents ◽  
Type Iii Secretion System ◽  
Polymyxin B ◽  
Secretion System ◽  
Effector Proteins ◽  
Secretion Systems ◽  
Type Iii ◽  
Genes Encoding

ABSTRACT The Salmonella typhimurium genome contains two pathogenicity islands (SPI) with genes encoding type III secretion systems for virulence proteins. SPI1 is required for the penetration of the epithelial layer of the intestine. SPI2 is important for the subsequent proliferation of bacteria in the spleens of infected hosts. Although most mutations in SPI2 lead to a strong reduction of virulence, they have different effects in vitro, with some mutants having significantly increased sensitivity to gentamicin and the antibacterial peptide polymyxin B. Previously we showed that certain mutations in SPI2 affect the ability of S. typhimurium to secrete SPI1 effector proteins and to invade cultured eukaryotic cells. In this study, we show that these SPI2 mutations affect the expression of the SPI1 invasion genes. Analysis of reporter fusions to various SPI1 genes reveals highly reduced expression of sipC,prgK, and hilA, the transcriptional activator of SPI1 genes. These observations indicate that the expression of one type III secretion system can be influenced dramatically by mutations in genes encoding a second type III secretion system in the same cell.

Deletion of the genes encoding the type III secretion system and cytotoxic enterotoxin alters host responses to Aeromonas hydrophila infection

2006 ◽  
Vol 40 (5) ◽  
pp. 198-210 ◽  
Author(s):  
Amin A. Fadl ◽  
Cristi L. Galindo ◽  
Jian Sha ◽  
Tatiana E. Erova ◽  
Clifford W. Houston ◽  
...  
Keyword(s):  
Aeromonas Hydrophila ◽  
Type Iii Secretion ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Host Responses ◽  
Type Iii ◽  
Genes Encoding

scholarly journals CesD2 of Enteropathogenic Escherichia coli Is a Second Chaperone for the Type III Secretion Translocator Protein EspD

2003 ◽  
Vol 71 (4) ◽  
pp. 2130-2141 ◽  
Author(s):  
Bianca C. Neves ◽  
Rosanna Mundy ◽  
Liljana Petrovska ◽  
Gordon Dougan ◽  
Stuart Knutton ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Type Iii Secretion ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Effector Proteins ◽  
Translocator Protein ◽  
Type Iii ◽  
Genes Encoding

ABSTRACT Enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic E. coli are extracellular pathogens that employ a type III secretion system to export translocator and effector proteins, proteins which facilitates colonization of the mucosal surface of the intestine via formation of attaching and effacing (A/E) lesions. The genes encoding the proteins for A/E lesion formation are located on a pathogenicity island, termed the locus of enterocyte effacement (LEE), which contains eae encoding intimin as well as the type III secretion system and effector genes. Many type III secreted proteins are stabilized and maintained in a secretion-competent conformation in the bacterial cytosol by specific chaperone proteins. Three type III chaperones have been described thus far within the EPEC LEE region: CesD, for the translocator proteins EspB and EspD; CesT, for the effector proteins Tir and Map; and CesF, for EspF. In this study we report the characterization of CesD2 (previously Orf27), a second LEE-encoded chaperone for EspD. We show specific CesD2-EspD protein interaction which appears to be necessary for proper EspD secretion in vitro and pathogenesis in vivo as demonstrated in the A/E-lesion-forming mouse pathogen Citrobacter rodentium.

scholarly journals Transcriptional profiling of three Pseudomonas syringae pv. actinidiae biovars reveals different responses to apoplast-like conditions related to strain virulence

2020 ◽  
Author(s):  
Elodie Vandelle ◽  
Teresa Colombo ◽  
Alice Regaiolo ◽  
Tommaso Libardi ◽  
Vanessa Maurizio ◽  
...  
Keyword(s):  
Gene Expression ◽  
Pseudomonas Syringae ◽  
Type Iii Secretion ◽  
Molecular Basis ◽  
Expression Profiles ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Type Iii ◽  
Genes Encoding ◽  
Operon Regulation

AbstractPseudomonas syringae pv. actinidiae (Psa) is a phytopathogen that causes devastating bacterial canker in kiwifruit. Among five biovars defined by genetic, biochemical and virulence traits, Psa3 is the most aggressive and is responsible for the most recent reported outbreaks, but the molecular basis of its heightened virulence is unclear. We therefore designed the first P. syringae multi-strain whole-genome microarray, encompassing biovars Psa1, Psa2 and Psa3 and the well-established model P. syringae pv. tomato, and analyzed early bacterial responses to an apoplast-like minimal medium. Transcriptomic profiling revealed (i) the strong activation in Psa3 of all hrp/hrc cluster genes, encoding components of the type III secretion system required for bacterial pathogenicity and involved in responses to environmental signals; (ii) potential repression of the hrp/hrc cluster in Psa2; and (iii) activation of flagellum-dependent cell motility and chemotaxis genes in Psa1. The detailed investigation of three gene families encoding upstream regulatory proteins (histidine kinases, their cognate response regulators, and proteins with diguanylate cyclase and/or phosphodiesterase domains) indicated that c-di-GMP may be a key regulator of virulence in Psa biovars. The gene expression data were supported by the quantification of biofilm formation. Our findings suggest that diverse early responses to the host apoplast, even among bacteria belonging to the same pathovar, can lead to different virulence strategies and may explain the differing outcomes of infections. Based on our detailed structural analysis of hrp operons, we also propose a revision of hrp cluster organization and operon regulation in P. syringae.Author summaryPseudomonas syringae pv. actinidiae (Psa) is a bacterial pathogen that infects kiwifruit crops. Recent outbreaks have been particularly devastating due to the emergence of a new biovar (Psa3), but the molecular basis of its virulence is unknown so it is difficult to develop mitigation strategies. In this study, we compared the gene expression profiles of Psa3 and various less-virulent biovars in an environment that mimics early infection, to determine the basis of pathogenicity. Genes involved in the assembly and activity of the type III secretion system, which is crucial for the secretion of virulence effectors, were strongly upregulated in Psa3 while lower or not expressed in the other biovars. We also observed the Psa3-specific expression of genes encoding upstream signaling components, confirming that strains of the same bacterial pathovar can respond differently to early contact with their host. Finally, our data suggested a key role in Psa virulence switch ability for the small chemical signaling molecule c-di-GMP, which suppresses the expression of virulence genes. This effect of c-di-GMP levels on Psa3 virulence should be further investigated and confirmed to develop new mitigation methods to target this pathway.

scholarly journals The type III secretion system of Proteus mirabilis HI4320 does not contribute to virulence in the mouse model of ascending urinary tract infection

2007 ◽  
Vol 56 (10) ◽  
pp. 1277-1283 ◽  
Author(s):  
Melanie M. Pearson ◽  
Harry L. T. Mobley
Keyword(s):  
Urinary Tract ◽  
Mouse Model ◽  
Proteus Mirabilis ◽  
Type Iii Secretion ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Negative Regulator ◽  
Wild Type ◽  
Type Iii ◽  
Tract Infections

The Gram-negative enteric bacterium Proteus mirabilis is a frequent cause of urinary tract infections (UTIs) in individuals with long-term indwelling catheters or with complicated urinary tracts. The recent release of the P. mirabilis strain HI4320 genome sequence has facilitated identification of potential virulence factors in this organism. Genes appearing to encode a type III secretion system (TTSS) were found in a low GC-content pathogenicity island in the P. mirabilis chromosome. This island contains 24 intact genes that appear to encode all components necessary to assemble a TTSS needle complex, plus at least two putative secreted effector proteins and their chaperones. The genetic organization of the TTSS genes is very similar to that of the TTSS of Shigella flexneri. RT-PCR analysis indicated that these genes are expressed at low levels in vitro. However, insertional mutation of two putative TTSS genes, encoding the requisite ATPase and a possible negative regulator, resulted in no change in either the growth rate of the mutant or the secreted protein profile compared to wild-type. Furthermore, there was no difference in quantitative cultures of urine, bladder and kidney between the ATPase mutant and the wild-type strain in the mouse model of ascending UTI in either independent challenge or co-challenge experiments. The role of the P. mirabilis TTSS, if any, is yet to be determined.

scholarly journals Closing the Circle on the Discovery of Genes Encoding Hrp Regulon Members and Type III Secretion System Effectors in the Genomes of Three Model Pseudomonas syringae Strains

2006 ◽  
Vol 19 (11) ◽  
pp. 1151-1158 ◽  
Author(s):  
Magdalen Lindeberg ◽  
Samuel Cartinhour ◽  
Christopher R. Myers ◽  
Lisa M. Schechter ◽  
David J. Schneider ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Type Iii Secretion ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Effector Proteins ◽  
Active Member ◽  
Tomato Dc3000 ◽  
Type Iii ◽  
Effector Genes ◽  
Genes Encoding

Pseudomonas syringae strains translocate large and distinct collections of effector proteins into plant cells via the type III secretion system (T3SS). Mutations in T3SS-encoding hrp genes are unable to elicit the hypersensitive response or pathogenesis in nonhost and host plants, respectively. Mutations in individual effectors lack strong phenotypes, which has impeded their discovery. P. syringae effectors are designated Hop (Hrp outer protein) or Avr (avirulence) proteins. Some Hop proteins are considered to be extracellular T3SS helpers acting at the plant-bacterium interface. Identification of complete sets of effectors and related proteins has been enabled by the application of bioinformatic and high-throughput experimental techniques to the complete genome sequences of three model strains: P. syringae pv. tomato DC3000, P. syringae pv. phaseolicola 1448A, and P. syringae pv. syringae B728a. Several recent papers, including three in this issue of Molecular Plant-Microbe Interactions, address the effector inventories of these strains. These studies establish that active effector genes in P. syringae are expressed by the HrpL alternative sigma factor and can be predicted on the basis of cis Hrp promoter sequences and N-terminal amino-acid patterns. Among the three strains analyzed, P. syringae pv. tomato DC3000 has the largest effector inventory and P. syringae pv. syringae B728a has the smallest. Each strain has several effector genes that appear inactive. Only five of the 46 effector families that are represented in these three strains have an active member in all of the strains. Web-based community resources for managing and sharing growing information on these complex effector arsenals should help future efforts to understand how effectors promote P. syringae virulence.

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