scholarly journals Genome-Wide Screening of Genes Required for Swarming Motility in Escherichia coli K-12

2006 ◽  
Vol 189 (3) ◽  
pp. 950-957 ◽  
Author(s):  
Tetsuyoshi Inoue ◽  
Ryuji Shingaki ◽  
Shotaro Hirose ◽  
Kaori Waki ◽  
Hirotada Mori ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Iron Acquisition ◽  
Tricarboxylic Acid Cycle ◽  
Common Antigen ◽  
Surface Acting ◽  
Swarming Motility ◽  
E Coli ◽  
Comprehensive Collection ◽  
Enterobacterial Common Antigen ◽  
K 12

ABSTRACT Escherichia coli K-12 has the ability to migrate on semisolid media by means of swarming motility. A systematic and comprehensive collection of gene-disrupted E. coli K-12 mutants (the Keio collection) was used to identify the genes involved in the swarming motility of this bacterium. Of the 3,985 nonessential gene mutants, 294 were found to exhibit a strongly repressed-swarming phenotype. Further, 216 of the 294 mutants displayed no significant defects in swimming motility; therefore, the 216 genes were considered to be specifically associated with the swarming phenotype. The swarming-associated genes were classified into various functional categories, indicating that swarming is a specialized form of motility that requires a wide variety of cellular activities. These genes include genes for tricarboxylic acid cycle and glucose metabolism, iron acquisition, chaperones and protein-folding catalysts, signal transduction, and biosynthesis of cell surface components, such as lipopolysaccharide, the enterobacterial common antigen, and type 1 fimbriae. Lipopolysaccharide and the enterobacterial common antigen may be important surface-acting components that contribute to the reduction of surface tension, thereby facilitating the swarm migration in the E. coli K-12 strain.

scholarly journals O Acetylation of the Enterobacterial Common Antigen Polysaccharide Is Catalyzed by the Product of the yiaH Gene of Escherichia coli K-12

2006 ◽  
Vol 188 (21) ◽  
pp. 7542-7550 ◽  
Author(s):  
Junko Kajimura ◽  
Arifur Rahman ◽  
James Hsu ◽  
Matthew R. Evans ◽  
Kevin H. Gardner ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Water Soluble ◽  
Hydroxyl Group ◽  
Insertion Mutagenesis ◽  
Amino Sugars ◽  
Common Antigen ◽  
Putative Gene ◽  
E Coli ◽  
Enterobacterial Common Antigen ◽  
K 12

ABSTRACT The carbohydrate component of the enterobacterial common antigen (ECA) of Escherichia coli K-12 occurs primarily as a water-soluble cyclic polysaccharide located in the periplasm (ECACYC) and as a phosphoglyceride-linked linear polysaccharide located on the cell surface (ECAPG). The polysaccharides of both forms are comprised of the amino sugars N-acetyl-d-glucosamine (GlcNAc), N-acetyl-d-mannosaminuronic acid (ManNAcA), and 4-acetamido-4,6-dideoxy-d-galactose (Fuc4NAc). These amino sugars are linked to one another to form trisaccharide repeat units with the structure →3-α-d-Fuc4NAc-(1→4)-β-d-ManNAcA-(1→4)-α-d-GlcNAc-(1→. The hydroxyl group in the 6 position of the GlcNAc residues of both ECACYC and ECAPG are nonstoichiometrically esterified with acetyl groups. Random transposon insertion mutagenesis of E. coli K-12 resulted in the generation of a mutant defective in the incorporation of O-acetyl groups into both ECACYC and ECAPG. This defect was found to be due to an insertion of the transposon into the yiaH locus, a putative gene of unknown function located at 80.26 min on the E. coli chromosomal map. Bioinformatic analyses of the predicted yiaH gene product indicate that it is an integral inner membrane protein that is a member of an acyltransferase family of enzymes found in a wide variety of organisms. The results of biochemical and genetic experiments presented here strongly support the conclusion that yiaH encodes the O-acetyltransferase responsible for the incorporation of O-acetyl groups into both ECACYC and ECAPG. Accordingly, we propose that this gene be designated wecH.

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.

Deletion of the Escherichia coli O14:K7 O antigen gene cluster

2004 ◽  
Vol 50 (4) ◽  
pp. 299-302 ◽  
Author(s):  
Slade O Jensen ◽  
Peter R Reeves
Keyword(s):  
Escherichia Coli ◽  
Gene Cluster ◽  
Gene Clusters ◽  
Common Antigen ◽  
E Coli ◽  
Antigen Gene ◽  
O Antigen ◽  
Enterobacterial Common Antigen ◽  
Colanic Acid ◽  
Rough Strain

Escherichia coli O14:K7 is a rough strain, lacking a typical O antigen, in which the enterobacterial common antigen is attached to the lipopolysaccharide core. The rough phenotype was previously mapped to the O antigen gene cluster; however, the nature of the nonfunctional locus was not defined. In this study, we have shown that the O antigen gene cluster of an O14:K7 type strain (Su4411/41) was most likely deleted via homologous recombination between the GDP–mannose pathway genes (manB and manC) of the colanic acid and O antigen gene clusters. A similar recombination event has previously been inferred for the deletion of E. coli Sonnei chromosomal O antigen genes. Therefore, recombination between the GDP–mannose pathway genes provides a convenient mechanism for the deletion of O antigen genes, which may occur if the typical O antigen becomes redundant.Key words: colanic acid, enterobacterial common antigen, GDP–mannose pathway, O14:K7, O antigen.

scholarly journals Indole-3-acetic acid regulates the central metabolic pathways in Escherichia coli

Microbiology ◽  
2006 ◽  
Vol 152 (8) ◽  
pp. 2421-2431 ◽  
Author(s):  
C. Bianco ◽  
E. Imperlini ◽  
R. Calogero ◽  
B. Senatore ◽  
P. Pucci ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Metabolic Pathways ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Mrna Levels ◽  
Glyoxylate Shunt ◽  
Acetyl Coa ◽  
Acid Cycle ◽  
E Coli ◽  
K 12

The physiological changes induced by indoleacetic acid (IAA) treatment were investigated in the totally sequenced Escherichia coli K-12 MG1655. DNA macroarrays were used to measure the mRNA levels for all the 4290 E. coli protein-coding genes; 50 genes (1.1 %) exhibited significantly different expression profiles. In particular, genes involved in the tricarboxylic acid cycle, the glyoxylate shunt and amino acid biosynthesis (leucine, isoleucine, valine and proline) were up-regulated, whereas the fermentative adhE gene was down-regulated. To confirm the indications obtained from the macroarray analysis the activity of 34 enzymes involved in central metabolism was measured; this showed an activation of the tricarboxylic acid cycle and the glyoxylate shunt. The malic enzyme, involved in the production of pyruvate, and pyruvate dehydrogenase, required for the channelling of pyruvate into acetyl-CoA, were also induced in IAA-treated cells. Moreover, it was shown that the enhanced production of acetyl-CoA and the decrease of NADH/NAD+ ratio are connected with the molecular process of the IAA response. The results demonstrate that IAA treatment is a stimulus capable of inducing changes in gene expression, enzyme activity and metabolite level involved in central metabolic pathways in E. coli.

scholarly journals Accumulation of the Enterobacterial Common Antigen Lipid II Biosynthetic Intermediate StimulatesdegP Transcription in Escherichia coli

1998 ◽  
Vol 180 (22) ◽  
pp. 5875-5884 ◽  
Author(s):  
Paul N. Danese ◽  
George R. Oliver ◽  
Kathleen Barr ◽  
Gregory D. Bowman ◽  
Paul D. Rick ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Signal Transduction ◽  
Heat Shock ◽  
Outer Membrane ◽  
Common Antigen ◽  
E Coli ◽  
Outer Leaflet ◽  
Lipid Ii ◽  
Enterobacterial Common Antigen ◽  
Two Component Signal Transduction

ABSTRACT In Escherichia coli, transcription of thedegP locus, which encodes a heat-shock-inducible periplasmic protease, is controlled by two parallel signal transduction systems that each monitor extracytoplasmic protein physiology. For example, the heat-shock-inducible sigma factor, ςE, controls degP transcription in response to the overproduction and folded state of various extracytoplasmic proteins. Similarly, the CpxA/R two-component signal transduction system increases degP transcription in response to the overproduction of a variety of extracytoplasmic proteins. SincedegP transcription is attuned to the physiology of extracytoplasmic proteins, we were interested in identifying negative transcriptional regulators of degP. To this end, we screened for null mutations that increased transcription from a strain containing a degP-lacZ reporter fusion. Through this approach, we identified null mutations in the wecE,rmlA ECA, and wecF loci that increase degP transcription. Interestingly, each of these loci is responsible for synthesis of the enterobacterial common antigen (ECA), a glycolipid situated on the outer leaflet of the outer membrane of members of the family Enterobacteriaceae. However, these null mutations do not stimulate degP transcription by eliminating ECA biosynthesis. Rather, the wecE,rmlA ECA, and wecF null mutations each impede the same step in ECA biosynthesis, and it is the accumulation of the ECA biosynthetic intermediate, lipid II, that causes the observed perturbations. For example, the lipid II-accumulating mutant strains each (i) confer upon E. colia sensitivity to bile salts, (ii) confer a sensitivity to the synthesis of the outer membrane protein LamB, and (iii) stimulate both the Cpx pathway and ςE activity. These phenotypes suggest that the accumulation of lipid II perturbs the structure of the bacterial outer membrane. Furthermore, these results underscore the notion that although the Cpx and ςE systems function in parallel to regulate degP transcription, they can be simultaneously activated by the same perturbation.

scholarly journals Glycolytic and Gluconeogenic Growth of Escherichia coli O157:H7 (EDL933) and E. coli K-12 (MG1655) in the Mouse Intestine

2004 ◽  
Vol 72 (3) ◽  
pp. 1666-1676 ◽  
Author(s):  
Regina L. Miranda ◽  
Tyrrell Conway ◽  
Mary P. Leatham ◽  
Dong Eun Chang ◽  
Wendy E. Norris ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Tricarboxylic Acid Cycle ◽  
Initial Growth ◽  
Intestinal Epithelial ◽  
E Coli ◽  
Intestinal Mucus ◽  
Large Numbers ◽  
Mouse Intestine ◽  
K 12 ◽  
Gluconeogenic Substrates

ABSTRACT Escherichia coli EDL933, an O157:H7 strain, is known to colonize the streptomycin-treated CD-1 mouse intestine by growing in intestinal mucus (E. A. Wadolkowski, J. A. Burris, and A. D. O'Brien, Infect. Immun. 58:2438-2445, 1990), but what nutrients and metabolic pathways are employed during colonization has not been determined. In this study, when the wild-type EDL933 strain was fed to mice along with an EDL933 ΔppsA ΔpckA mutant, which is unable to utilize tricarboxylic acid cycle intermediates and gluconeogenic substrates for growth, both strains colonized the mouse intestine equally well. Therefore, EDL933 utilizes a glycolytic substrate(s) for both initial growth and maintenance when it is the only E. coli strain fed to the mice. However, in the presence of large numbers of MG1655, a K-12 strain, it is shown that EDL933 utilizes a glycolytic substrate(s) for initial growth in the mouse intestine but appears to utilize both glycolytic and gluconeogenic substrates in an attempt to maintain colonization. It is further shown that MG1655 predominantly utilizes glycolytic substrates for growth in the mouse intestine whether growing in the presence or absence of large numbers of EDL933. Data are presented showing that although small numbers of EDL933 grow to large numbers in the intestine in the presence of large numbers of MG1655 when both strains are fed to mice simultaneously, precolonization with MG1655 affords protection against subsequent colonization by EDL933. Moreover, in mice that are precolonized with EDL933, small numbers of MG1655 are able to grow rapidly in the intestine and EDL933 is eliminated. In situ hybridization experiments using E. coli-specific rRNA probes showed that while MG1655 is found only in mucus, EDL933 is found both in mucus and closely associated with intestinal epithelial cells. The data are discussed with respect to competition for nutrients and to the protection that some intestinal commensal E. coli strains might afford against infection by O157:H7 strains.

scholarly journals Defining Genomic Islands and Uropathogen-Specific Genes in Uropathogenic Escherichia coli

2007 ◽  
Vol 189 (9) ◽  
pp. 3532-3546 ◽  
Author(s):  
Amanda L. Lloyd ◽  
David A. Rasko ◽  
Harry L. T. Mobley
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Iron Acquisition ◽  
Genomic Islands ◽  
Comparative Genomic ◽  
Upec Strain ◽  
E Coli ◽  
Strain Collection ◽  
Tract Infections ◽  
K 12

ABSTRACT Uropathogenic Escherichia coli (UPEC) strains are responsible for the majority of uncomplicated urinary tract infections, which can present clinically as cystitis or pyelonephritis. UPEC strain CFT073, isolated from the blood of a patient with acute pyelonephritis, was most cytotoxic and most virulent in mice among our strain collection. Based on the genome sequence of CFT073, microarrays were utilized in comparative genomic hybridization (CGH) analysis of a panel of uropathogenic and fecal/commensal E. coli isolates. Genomic DNA from seven UPEC (three pyelonephritis and four cystitis) isolates and three fecal/commensal strains, including K-12 MG1655, was hybridized to the CFT073 microarray. The CFT073 genome contains 5,379 genes; CGH analysis revealed that 2,820 (52.4%) of these genes were common to all 11 E. coli strains, yet only 173 UPEC-specific genes were found by CGH to be present in all UPEC strains but in none of the fecal/commensal strains. When the sequences of three additional sequenced UPEC strains (UTI89, 536, and F11) and a commensal strain (HS) were added to the analysis, 131 genes present in all UPEC strains but in no fecal/commensal strains were identified. Seven previously unrecognized genomic islands (>30 kb) were delineated by CGH in addition to the three known pathogenicity islands. These genomic islands comprise 672 kb of the 5,231-kb (12.8%) genome, demonstrating the importance of horizontal transfer for UPEC and the mosaic structure of the genome. UPEC strains contain a greater number of iron acquisition systems than do fecal/commensal strains, which is reflective of the adaptation to the iron-limiting urinary tract environment. Each strain displayed distinct differences in the number and type of known virulence factors. The large number of hypothetical genes in the CFT073 genome, especially those shown to be UPEC specific, strongly suggests that many urovirulence factors remain uncharacterized.

scholarly journals A Novel Gene Required for Rhamnose-Glucose Polysaccharide Synthesis in Streptococcus mutans

1999 ◽  
Vol 181 (20) ◽  
pp. 6556-6559 ◽  
Author(s):  
Yoshihisa Yamashita ◽  
Yukie Shibata ◽  
Yoshio Nakano ◽  
Hiromasa Tsuda ◽  
Nobuo Kido ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Streptococcus Mutans ◽  
Common Antigen ◽  
E Coli ◽  
Novel Gene ◽  
Enterobacterial Common Antigen ◽  
Polysaccharide Synthesis ◽  
O Antigens

ABSTRACT Gene rgpG is required for biosynthesis of rhamnose-glucose polysaccharide (RGP) in Streptococcus mutans. Its deduced amino acid sequence had similarity to WecA, which initiates syntheses of enterobacterial common antigen and some O antigens in Escherichia coli. Gene rgpGcomplemented a wecA mutation of E. coli, suggesting that rgpG may function similarly in RGP synthesis.

scholarly journals Lipopolysaccharide-Linked Enterobacterial Common Antigen (ECALPS) Occurs in Rough Strains of Escherichia coli R1, R2, and R4

2020 ◽  
Vol 21 (17) ◽  
pp. 6038
Author(s):  
Anna Maciejewska ◽  
Marta Kaszowska ◽  
Wojciech Jachymek ◽  
Czeslaw Lugowski ◽  
Jolanta Lukasiewicz
Keyword(s):  
Escherichia Coli ◽  
Surface Antigen ◽  
Structural Data ◽  
Outer Core ◽  
Permeability Barrier ◽  
Common Antigen ◽  
Enterobacterial Common Antigen ◽  
Specific Polysaccharide ◽  
K 12 ◽  
Outer Membrane Permeability

Enterobacterial common antigen (ECA) is a conserved surface antigen characteristic for Enterobacteriaceae. It is consisting of trisaccharide repeating unit, →3)-α-d-Fucp4NAc-(1→4)-β-d-ManpNAcA-(1→4)-α-d-GlcpNAc-(1→, where prevailing forms include ECA linked to phosphatidylglycerol (ECAPG) and cyclic ECA (ECACYC). Lipopolysaccharide (LPS)-associated form (ECALPS) has been proved to date only for rough Shigella sonnei phase II. Depending on the structure organization, ECA constitutes surface antigen (ECAPG and ECALPS) or maintains the outer membrane permeability barrier (ECACYC). The existence of LPS was hypothesized in the 1960–80s on the basis of serological observations. Only a few Escherichia coli strains (i.e., R1, R2, R3, R4, and K-12) have led to the generation of anti-ECA antibodies upon immunization, excluding ECAPG as an immunogen and conjecturing ECALPS as the only immunogenic form. Here, we presented a structural survey of ECALPS in E. coli R1, R2, R3, and R4 to correlate previous serological observations with the presence of ECALPS. The low yields of ECALPS were identified in the R1, R2, and R4 strains, where ECA occupied outer core residues of LPS that used to be substituted by O-specific polysaccharide in the case of smooth LPS. Previously published observations and hypotheses regarding the immunogenicity and biosynthesis of ECALPS were discussed and correlated with presented herein structural data.

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