scholarly journals The Pathogenicity Island-Associated K15 Capsule Determinant Exhibits a Novel Genetic Structure and Correlates with Virulence in Uropathogenic Escherichia coli Strain 536

2004 ◽  
Vol 72 (10) ◽  
pp. 5993-6001 ◽  
Author(s):  
György Schneider ◽  
Ulrich Dobrindt ◽  
Holger Brüggemann ◽  
Gábor Nagy ◽  
Britta Janke ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Gene Cluster ◽  
Pathogenicity Island ◽  
Coli Strain ◽  
Open Reading Frames ◽  
E Coli ◽  
Secretion Pathway ◽  
Encoding Gene ◽  
Group 2 ◽  
K 12

ABSTRACT The K15 capsule determinant of uropathogenic Escherichia coli strain 536 (O6:K15:H31) is part of a novel 79.6-kb pathogenicity island (PAI) designated PAI V536 that is absent from the genome of nonpathogenic E. coli K-12 strain MG1655. PAI V536 shows typical characteristics of a composite PAI that is associated with the pheV tRNA gene and contains the pix fimbriae determinant as well as genes coding for a putative phosphoglycerate transport system, an autotransporter protein, and hypothetical open reading frames. A gene cluster coding for a putative general secretion pathway system, together with a kps K15 determinant, is localized downstream of a truncated pheV gene (′pheV) also present in this chromosomal region. The distribution of genes present on PAI V536 was studied by PCR in different pathogenic and nonpathogenic E. coli isolates of various sources. Analysis of the 20-kb kps locus revealed a so far unknown genetic organization. Generally, the kps K15 gene cluster resembles that of group 2 and 3 capsules, where two conserved regions (regions 1 and 3) are located up- or downstream of a highly variable serotype-specific region (region 2). Interestingly, recombination of a group 2 and 3 determinant may have been involved in the evolution of the K15 capsule-encoding gene cluster. Expression of the K15 capsule is important for virulence in a murine model of ascending urinary tract infection but not for serum resistance of E. coli strain 536.

scholarly journals afa-8 Gene Cluster Is Carried by a Pathogenicity Island Inserted into the tRNAPhe of Human and Bovine Pathogenic Escherichia coli Isolates

2001 ◽  
Vol 69 (2) ◽  
pp. 937-948 ◽  
Author(s):  
Lila Lalioui ◽  
Chantal Le Bouguénec
Keyword(s):  
Escherichia Coli ◽  
Direct Repeat ◽  
Pathogenicity Island ◽  
Genomic Region ◽  
Open Reading Frames ◽  
Blood Isolate ◽  
Distinctive Features ◽  
E Coli ◽  
Pathogenic Escherichia Coli ◽  
K 12

ABSTRACT We recently described a new afimbrial adhesin, AfaE-VIII, produced by animal strains associated with diarrhea and septicemia and by human isolates associated with extraintestinal infections. Here, we report that the afa-8 operon, encoding AfaE-VIII adhesin, from the human blood isolate Escherichia coli AL862 is carried by a 61-kb genomic region with characteristics typical of a pathogenicity island (PAI), including a size larger than 10 kb, the presence of an integrase-encoding gene, the insertion into a tRNA locus (pheR), and the presence of a small direct repeat at each extremity. Moreover, the G+C content of the afa-8 operon (46.4%) is lower than that of the E. coli K-12/MG1655 chromosome (50.8%). Within this PAI, designated PAI IAL862, we identified open reading frames able to code for products similar to proteins involved in sugar utilization. Four probes spanning these sequences hybridized with 74.3% of pathogenicafa-8-positive E. coli strains isolated from humans and animals, 25% of human pathogenic afa-8-negativeE. coli strains, and only 8% of fecal strains (P = 0.05), indicating that these sequences are strongly associated with the afa-8 operon and that this genetic association may define a PAI widely distributed among human and animal afa-8-positive strains. One of the distinctive features of this study is that E. coli AL862 also carries another afa-8-containing PAI (PAI IIAL862), which appeared to be similar in size and genetic organization to PAI IAL862 and was inserted into the pheV gene. We investigated the insertion sites of afa-8-containing PAI in human and bovine pathogenic E. coli strains and found that this PAI preferentially inserted into the pheV gene.

scholarly journals Identification of Candidates for a Subunit Vaccine against Extraintestinal Pathogenic Escherichia coli

2006 ◽  
Vol 75 (4) ◽  
pp. 1916-1925 ◽  
Author(s):  
Lionel Durant ◽  
Arnaud Metais ◽  
Coralie Soulama-Mouze ◽  
Jean-Marie Genevard ◽  
Xavier Nassif ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Subunit Vaccine ◽  
Iron Acquisition ◽  
Passive Immunization ◽  
Open Reading Frames ◽  
Lethal Challenge ◽  
E Coli ◽  
Protective Antigens ◽  
K 12 ◽  
Genomic Regions

ABSTRACT Extraintestinal pathogenic Escherichia coli (ExPEC) strains cause a large spectrum of infections. The majority of ExPEC strains are closely related to the B2 or the D phylogenetic group. The aim of our study was to develop a protein-based vaccine against these ExPEC strains. To this end, we identified ExPEC-specific genomic regions, using a comparative genome analysis, between the nonpathogenic E. coli strain K-12 MG1655 and ExPEC strains C5 (meningitis isolate) and CFT073 (urinary tract infection isolate). The analysis of these genomic regions allowed the selection of 40 open reading frames, which are conserved among B2/D clinical isolates and encode proteins with putative outer membrane localization. These genes were cloned, and recombinant proteins were purified and assessed as vaccine candidates. After immunization of BALB/c mice, five proteins induced a significant protective immunity against a lethal challenge with a clinical E. coli strain of the B2 group. In passive immunization assays, antigen-specific antibodies afforded protection to naive mice against a lethal challenge. Three of these antigens were related to iron acquisition metabolism, an important virulence factor of the ExPEC, and two corresponded to new, uncharacterized proteins. Due to the large number of genetic differences that exists between commensal and pathogenic strains of E. coli, our results demonstrate that it is possible to identify targets that elicit protective immune responses specific to those strains. The five protective antigens could constitute the basis for a preventive subunit vaccine against diseases caused by ExPEC strains.

Polarity and the regulation of the ilv gene cluster in Escherichia coli strain K-12

1976 ◽  
Vol 148 (2) ◽  
pp. 111-124 ◽  
Author(s):  
John M. Smith ◽  
David E. Smolin ◽  
H. Edwin Umbarger
Keyword(s):  
Escherichia Coli ◽  
Gene Cluster ◽  
Coli Strain ◽  
K 12

scholarly journals The Putrescine Importer PuuP of Escherichia coli K-12

2009 ◽  
Vol 191 (8) ◽  
pp. 2776-2782 ◽  
Author(s):  
Shin Kurihara ◽  
Yuichi Tsuboi ◽  
Shinpei Oda ◽  
Hyeon Guk Kim ◽  
Hidehiko Kumagai ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Gene Cluster ◽  
Growth Phase ◽  
Exponential Growth ◽  
Minimal Medium ◽  
Exponential Growth Phase ◽  
E Coli ◽  
Genes Encoding ◽  
K 12 ◽  
Utilization Pathway

ABSTRACT The Puu pathway is a putrescine utilization pathway involving gamma-glutamyl intermediates. The genes encoding the enzymes of the Puu pathway form a gene cluster, the puu gene cluster, and puuP is one of the genes in this cluster. In Escherichia coli, three putrescine importers, PotFGHI, PotABCD, and PotE, were discovered in the 1990s and have been studied; however, PuuP had not been discovered previously. This paper shows that PuuP is a novel putrescine importer whose kinetic parameters are equivalent to those of the polyamine importers discovered previously. A puuP + strain absorbed up to 5 mM putrescine from the medium, but a ΔpuuP strain did not. E. coli strain MA261 has been used in previous studies of polyamine transporters, but PuuP had not been identified previously. It was revealed that the puuP gene of MA261 was inactivated by a point mutation. When E. coli was grown on minimal medium supplemented with putrescine as the sole carbon or nitrogen source, only PuuP among the polyamine importers was required. puuP was expressed strongly when putrescine was added to the medium or when the puuR gene, which encodes a putative repressor, was deleted. When E. coli was grown in M9-tryptone medium, PuuP was expressed mainly in the exponential growth phase, and PotFGHI was expressed independently of the growth phase.

scholarly journals Quorum-Sensing Escherichia coli Regulator A: a Regulator of the LysR Family Involved in the Regulation of the Locus of Enterocyte Effacement Pathogenicity Island in Enterohemorrhagic E. coli

2002 ◽  
Vol 70 (6) ◽  
pp. 3085-3093 ◽  
Author(s):  
Vanessa Sperandio ◽  
Caiyi C. Li ◽  
James B. Kaper
Keyword(s):  
Escherichia Coli ◽  
Quorum Sensing ◽  
Type Iii Secretion ◽  
Pathogenicity Island ◽  
The Other ◽  
E Coli ◽  
Type Iii ◽  
Enterocyte Effacement ◽  
K 12 ◽  
Lysr Family

ABSTRACT The locus of enterocyte effacement (LEE) is a chromosomal pathogenicity island that encodes the proteins involved in the formation of the attaching and effacing lesions by enterohemorrhagic Escherichia coli (EHEC) and enteropathogenic E. coli (EPEC). The LEE comprises 41 open reading frames organized in five major operons, LEE1, LEE2, LEE3, tir (LEE5), and LEE4, which encode a type III secretion system, the intimin adhesin, the translocated intimin receptor (Tir), and other effector proteins. The first gene of LEE1 encodes the Ler regulator, which activates all the other genes within the LEE. We previously reported that the LEE genes were activated by quorum sensing through Ler (V. Sperandio, J. L. Mellies, W. Nguyen, S. Shin, and J. B. Kaper, Proc. Natl. Acad. Sci. USA 96:15196-15201, 1999). In this study we report that a putative regulator in the E. coli genome is itself activated by quorum sensing. This regulator is encoded by open reading frame b3243; belongs to the LysR family of regulators; is present in EHEC, EPEC, and E. coli K-12; and shares homology with the AphB and PtxR regulators of Vibrio cholerae and Pseudomonas aeruginosa, respectively. We confirmed the activation of b3243 by quorum sensing by using transcriptional fusions and renamed this regulator quorum-sensing E. coli regulator A (QseA). We observed that QseA activated transcription of ler and therefore of the other LEE genes. An EHEC qseA mutant had a striking reduction of type III secretion activity, which was complemented when qseA was provided in trans. Similar results were also observed with a qseA mutant of EPEC. The QseA regulator is part of the regulatory cascade that regulates EHEC and EPEC virulence genes by quorum sensing.

scholarly journals Cloning, sequencing and expression in Escherichia coli of the rubredoxin gene from Clostridium pasteurianum

1992 ◽  
Vol 285 (1) ◽  
pp. 255-262 ◽  
Author(s):  
I Mathieu ◽  
J Meyer ◽  
J M Moulis
Keyword(s):  
Escherichia Coli ◽  
Protein Sequence ◽  
Coli Strain ◽  
Open Reading Frames ◽  
Transcriptional Unit ◽  
Clostridium Pasteurianum ◽  
Visible Absorption ◽  
E Coli ◽  
Sequencing And Expression ◽  
Reading Frames

A 3.9 kb BglII-HindIII DNA fragment containing the rubredoxin gene from Clostridium pasteurianum has been cloned using oligonucleotide probes designed from the protein sequence. The 2675 bp SspI-HindIII portion of this fragment has been sequenced and found to contain three open reading frames in addition to the rubredoxin gene. The putative product of one of these open reading frames is similar to various thioredoxin reductases. The rubredoxin gene translates into a sequence that differs from the previously published protein sequence in three positions, D-14, D-22 and E-48 being replaced by the corresponding amides. These changes have been confirmed by partial resequencing of the protein. Promoter-like sequences and a transcription termination signal have been found near the sequence of the rubredoxin gene, which may therefore constitute an independent transcriptional unit. Expression of C. pasteurianum rubredoxin in Escherichia coli strain JM109 has been optimized by subcloning a 476 bp SspI-SspI fragment encompassing the rubredoxin gene. Under these conditions, the latter gene was partly under the control of the lac promoter of pUC18, and the level of rubredoxin production could be increased twofold on addition of a lactose analogue, thus reaching 2-3 mg of pure protein/l of culture. Recombinant rubredoxin was produced in E. coli cells as the holoprotein, and displayed a u.v.-visible-absorption spectrum identical with that of the rubredoxin purified from C. pasteurianum. M.s. and N-terminal sequencing showed that C. pasteurianum rubredoxin expressed in E. coli differs from its native counterpart by having an unblocked N-terminal methionine.

scholarly journals Gene Cluster for Assembly of Pilus Colonization Factor Antigen III of Enterotoxigenic Escherichia coli

2001 ◽  
Vol 69 (9) ◽  
pp. 5864-5873 ◽  
Author(s):  
Tooru Taniguchi ◽  
Yukihiro Akeda ◽  
Ayako Haba ◽  
Yoko Yasuda ◽  
Koichiro Yamamoto ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Nucleotide Sequence ◽  
Gene Cluster ◽  
Enterotoxigenic Escherichia Coli ◽  
Human Colon Carcinoma Cell ◽  
E Coli ◽  
Colonization Factor ◽  
Type Iv ◽  
K 12 ◽  
Factor Antigen

ABSTRACT The assembly of pilus colonization factor antigen III (CFA/III) of enterotoxigenic Escherichia coli (ETEC) requires the processing of CFA/III major pilin (CofA) by a prepilin peptidase (CofP), similar to other type IV pilus formation systems. CofA is produced initially as a 26.5-kDa preform pilin (prepilin) and then processed to a 20.5-kDa mature pilin by CofP which is predicted to be localized in the inner membrane. In the present experiment, we determined the nucleotide sequence of the whole region for CFA/III formation and identified a cluster of 14 genes, includingcofA and cofP. Several proteins encoded bycof genes were similar to previously described proteins, such as the toxin-coregulated pili of Vibrio cholerae and the bundle-forming pili of enteropathogenic E. coli. The G+C content of the cof gene cluster was 37%, which was significantly lower than the average for the E. coli genome (50%). The introduction of a recombinant plasmid containing thecof gene cluster into the E. coli K-12 strain conferred CFA/III biogenesis and the ability of adhesion to the human colon carcinoma cell line Caco-2. This is the first report of a complete nucleotide sequence of the type IV pili found in human ETEC, and our results provide a useful model for studying the molecular mechanism of CFA/III biogenesis and the role of CFA/III in ETEC infection.

scholarly journals CS5 Pilus Biosynthesis Genes from Enterotoxigenic Escherichia coli O115:H40

1999 ◽  
Vol 181 (18) ◽  
pp. 5847-5851 ◽  
Author(s):  
Thomas G. Duthy ◽  
Lothar H. Staendner ◽  
Paul A. Manning ◽  
Michael W. Heuzenroeder
Keyword(s):  
Escherichia Coli ◽  
Dna Sequences ◽  
Surface Expression ◽  
Open Reading Frames ◽  
Enterotoxigenic Escherichia Coli ◽  
Cell Surface Expression ◽  
E Coli ◽  
Pilus Biogenesis ◽  
K 12 ◽  
And Function

ABSTRACT We have sequenced the entire region of DNA required for the biosynthesis of CS5 pili from enterotoxigenic Escherichia coli O115:H40 downstream of the major subunit gene, designatedcsfA (for coli surface factor five A). Five more open reading frames (ORFs) (csfB, csfC,csfE, csfF, and csfD) which are transcribed in the same direction as the major subunit and are flanked by a number of insertion sequence regions have been identified. T7 polymerase-mediated overexpression of the cloned csf ORFs confirmed protein sizes based on the DNA sequences that encode them. The expression of only the csf region in E. coli K-12 resulted in the hemagglutination of human erythrocytes and the cell surface expression of CS5 pili, suggesting that the cluster contains all necessary information for CS5 pilus biogenesis and function.

scholarly journals A Novel Pathogenicity Island Integrated Adjacent to the thrW tRNA Gene of Avian Pathogenic Escherichia coli Encodes a Vacuolating Autotransporter Toxin

2003 ◽  
Vol 71 (9) ◽  
pp. 5087-5096 ◽  
Author(s):  
V. R. Parreira ◽  
C. L. Gyles
Keyword(s):  
Escherichia Coli ◽  
Serine Protease ◽  
Trna Gene ◽  
Signal Sequence ◽  
Sequence Similarity ◽  
Pathogenicity Island ◽  
Open Reading Frames ◽  
Integrase Gene ◽  
E Coli ◽  
Reading Frames

ABSTRACT We report the complete nucleotide sequence and genetic organization of the Vat-encoding pathogenicity island (PAI) of avian pathogenic Escherichia coli strain Ec222. The 22,139-bp PAI is situated adjacent to the 3′ terminus of the thrW tRNA gene, has a G+C content of 41.2%, and includes a bacteriophage SfII integrase gene, mobile genetic elements, two open reading frames with products exhibiting sequence similarity to known proteins, and several other open reading frames of unknown function. The PAI encodes an autotransporter protein, Vat (vacuolating autotransporter toxin), which induces the formation of intracellular vacuoles resulting in cytotoxic effects similar to those caused by the VacA toxin from Helicobacter pylori. The predicted 148.3-kDa protein product possesses the three domains that are typical of serine protease autotransporters of Enterobacteriaceae: an N-terminal signal sequence of 55 amino acids, a 111.8-kDa passenger domain containing a modified serine protease site (ATSGSG), and a C-terminal outer membrane translocator of 30.5 kDa. Vat has 75% protein homology with the hemagglutinin Tsh, an autotransporter of avian pathogenic E. coli. A vat deletion mutant of Ec222 showed no virulence in respiratory and cellulitis infection models of disease in broiler chickens. We conclude that the newly described PAI and Vat may be involved in the pathogenicity of avian septicemic E. coli strain Ec222 and other avian pathogenic E. coli strains.

scholarly journals Asymptomatic bacteriuria Escherichia coli strain 83972 carries mutations in the foc locus and is unable to express F1C fimbriae

Microbiology ◽  
2006 ◽  
Vol 152 (6) ◽  
pp. 1799-1806 ◽  
Author(s):  
Viktoria Roos ◽  
Mark A. Schembri ◽  
Glen C. Ulett ◽  
Per Klemm
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Gene Cluster ◽  
Asymptomatic Bacteriuria ◽  
Human Kidney ◽  
Coli Strain ◽  
Gene Encoding ◽  
Symptomatic Urinary Tract Infection ◽  
E Coli ◽  
Colonization Factor

Escherichia coli is the most common organism associated with asymptomatic bacteriuria (ABU). In contrast to uropathogenic E. coli (UPEC), which causes symptomatic urinary tract infection (UTI), very little is known about the mechanisms by which these strains colonize the urinary tract. Bacterial adhesion conferred by specific surface-associated adhesins is normally considered as a prerequisite for colonization of the urinary tract. The prototype ABU E. coli strain 83972 was originally isolated from a girl who had carried it asymptomatically for 3 years. This study characterized the molecular status of one of the primary adhesion factors known to be associated with UTI, namely F1C fimbriae, encoded by the foc gene cluster. F1C fimbriae recognize receptors present in the human kidney and bladder. Expression of the foc genes was found to be up-regulated in human urine. It was also shown that although strain 83972 contains a seemingly intact foc gene cluster, F1C fimbriae are not expressed. Sequencing and genetic complementation revealed that the focD gene, encoding a component of the F1C transport and assembly system, was non-functional, explaining the inability of strain 83972 to express this adhesin. The data imply that E. coli 83972 has lost its ability to express this important colonization factor as a result of host-driven evolution. The ancestor of the strain seems to have been a pyelonephritis strain of phylogenetic group B2. Strain 83972 therefore represents an example of bacterial adaptation from pathogenicity to commensalism through virulence factor loss.

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