Escherichia coli O157:H7 Strain EDL933 Harbors Multiple Functional Prophage-Associated Genes Necessary for the Utilization of 5-N-Acetyl-9-O-Acetyl Neuraminic Acid as a Growth Substrate

ABSTRACTEnterohemorrhagicEscherichia coli(EHEC) O157:H7 strain EDL933 harbors multiple prophage-associated open reading frames (ORFs) in its genome which are highly homologous to the chromosomalnanSgene. The latter is part of thenanCMSoperon, which is present in mostE. colistrains and encodes an esterase which is responsible for the monodeacetylation of 5-N-acetyl-9-O-acetyl neuraminic acid (Neu5,9Ac2). Whereas one prophage-borne ORF (z1466) has been characterized in previous studies, the functions of the othernanS-homologous ORFs are unknown. In the current study, thenanS-homologous ORFs of EDL933 were initially studiedin silico. Due to their homology to the chromosomalnanSgene and their location in prophage genomes, we designated themnanS-p and numbered the differentnanS-p alleles consecutively from 1 to 10. The two allelesnanS-p2 andnanS-p4 were selected for production of recombinant proteins, their enzymatic activities were investigated, and differences in their temperature optima were found. Furthermore, a function of these enzymes in substrate utilization could be demonstrated using anE. coliC600ΔnanSmutant in a growth medium with Neu5,9Ac2as the carbon source and supplementation with the different recombinant NanS-p proteins. Moreover, generation of sequential deletions of allnanS-p alleles in strain EDL933 and subsequent growth experiments demonstrated a gene dose effect on the utilization of Neu5,9Ac2. Since Neu5,9Ac2is an important component of human and animal gut mucus and since the nutrient availability in the large intestine is limited, we hypothesize that the presence of multiple Neu5,9Ac2esterases provides them a nutrient supply under certain conditions in the large intestine, even if particular prophages are lost.IMPORTANCEIn this study, a group of homologous prophage-bornenanS-p alleles and two of the corresponding enzymes of enterohemorrhagicE. coli(EHEC) O157:H7 strain EDL933 that may be important to provide alternative genes for substrate utilization were characterized.

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Genome Sequence of a T4-like Phage, Escherichia Phage vB_EcoM-Sa45lw, Infecting Shiga Toxin-Producing Escherichia coli Strains

Microbiology Resource Announcements ◽

10.1128/mra.00804-19 ◽

2019 ◽

Vol 8 (32) ◽

Author(s):

Yen-Te Liao ◽

Yujie Zhang ◽

Alexandra Salvador ◽

Vivian C. H. Wu

Keyword(s):

Escherichia Coli ◽

Surface Water ◽

Genome Size ◽

Shiga Toxin ◽

Open Reading Frames ◽

Content Type ◽

E Coli ◽

Double Stranded Dna ◽

A Genome ◽

Reading Frames

Escherichia phage vB_EcoM-Sa45lw, a new member of the T4-like phages, was isolated from surface water in a produce-growing area. The phage, containing double-stranded DNA with a genome size of 167,353 bp and 282 predicted open reading frames (ORFs), is able to infect generic Escherichia coli and Shiga toxin-producing E. coli O45 and O157 strains.

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Magnesium Sensing Regulates Intestinal Colonization of Enterohemorrhagic Escherichia coli O157:H7

mBio ◽

10.1128/mbio.02470-20 ◽

2020 ◽

Vol 11 (6) ◽

Author(s):

Yutao Liu ◽

Runhua Han ◽

Junyue Wang ◽

Pan Yang ◽

Fang Wang ◽

...

Keyword(s):

Escherichia Coli ◽

Large Intestine ◽

Intestinal Tract ◽

Regulatory System ◽

Regulatory Pathway ◽

Content Type ◽

E Coli ◽

Low Magnesium ◽

Enterocyte Effacement

ABSTRACT The large intestinal pathogen enterohemorrhagic Escherichia coli (EHEC) O157:H7 detects host cues to regulate virulence gene expression during colonization and infection. However, virulence regulatory mechanisms of EHEC O157:H7 in the human large intestine are not fully understood. Herein, we identified a virulence-regulating pathway where the PhoQ/PhoP two-component regulatory system senses low magnesium levels and signals to the O island 119-encoded Z4267 (LmiA; low magnesium-induced regulator A), directly activating loci of enterocyte effacement genes to promote EHEC O157:H7 adherence in the large intestine. Disruption of this pathway significantly decreased EHEC O157:H7 adherence in the mouse intestinal tract. Moreover, feeding mice a magnesium-rich diet significantly reduced EHEC O157:H7 adherence in vivo. This LmiA-mediated virulence regulatory pathway is also conserved among several EHEC and enteropathogenic E. coli serotypes; therefore, our findings support the use of magnesium as a dietary supplement and provide greater insights into the dietary cues that can prevent enteric infections. IMPORTANCE Sensing specific gut metabolites is an important strategy for inducing crucial virulence programs by enterohemorrhagic Escherichia coli (EHEC) O157:H7 during colonization and infection. Here, we identified a virulence-regulating pathway wherein the PhoQ/PhoP two-component regulatory system signals to the O island 119-encoded low magnesium-induced regulator A (LmiA), which, in turn, activates locus of enterocyte effacement (LEE) genes to promote EHEC O157:H7 adherence in the low-magnesium conditions of the large intestine. This regulatory pathway is widely present in a range of EHEC and enteropathogenic E. coli (EPEC) serotypes. Disruption of this pathway significantly decreased EHEC O157:H7 adherence in the mouse intestinal tract. Moreover, mice fed a magnesium-rich diet showed significantly reduced EHEC O157:H7 adherence in vivo, indicating that magnesium may help in preventing EHEC and EPEC infection in humans.

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T4-Like Phage Bp7, a Potential Antimicrobial Agent for Controlling Drug-Resistant Escherichia coli in Chickens

Applied and Environmental Microbiology ◽

10.1128/aem.01505-13 ◽

2013 ◽

Vol 79 (18) ◽

pp. 5559-5565 ◽

Cited By ~ 21

Author(s):

Can Zhang ◽

Wenli Li ◽

Wenhua Liu ◽

Ling Zou ◽

Chen Yan ◽

...

Keyword(s):

Escherichia Coli ◽

Burst Size ◽

Multidrug Resistant ◽

Open Reading Frames ◽

Attractive Alternative ◽

Drug Resistant ◽

Animal Cells ◽

Content Type ◽

E Coli ◽

Chicken Feces

ABSTRACTChicken-pathogenicEscherichia coliis severely endangering the poultry industry in China and worldwide, and antibiotic therapy is facing an increasing problem of antibiotic resistance. Bacteriophages can kill bacteria with no known activity in human or animal cells, making them an attractive alternative to antibiotics. In this study, we present the characteristics of a novel virulent bacteriophage, Bp7, specifically infecting pathogenic multidrug-resistantE. coli. Phage Bp7 was isolated from chicken feces. Bp7 belongs to the familyMyoviridae, possessing an elongated icosahedral head and contractile sheathed tail. It has a 168-kb double-stranded DNA genome. For larger yields, its optimal multiplicity of infection (MOI) to infectE. coliwas about 0.001. The latent period was 10 to 15 min, and the burst size was 90 PFU/infected cell. It was stable both at pH 5.0 to 10.0 and at 40°C or 50°C for at least 1 h. Bp7 could infect 46% of pathogenic clinicalE. colistrains. Bp7 harbored 791 open reading frames (ORFs) and 263 possible genes. Among the 263 genes, 199 possessed amino acid sequence identities with ORFs of phage T4, 62 had identities with other T4-like phages, and only one lacked any database match. The genome of Bp7 manifested obvious division and rearrangement compared to phages T4, JS98, and IME08. Bp7 is a new member of the “T4-like” genus, familyMyoviridae. Its wide host range, strong cell-killing activity, and high stability to pH make it an alternative to antimicrobials for controlling drug-resistantE. coliin chickens.

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The Protein Interaction Network of Bacteriophage Lambda with Its Host, Escherichia coli

Journal of Virology ◽

10.1128/jvi.02495-13 ◽

2013 ◽

Vol 87 (23) ◽

pp. 12745-12755 ◽

Cited By ~ 16

Author(s):

Sonja Blasche ◽

Stefan Wuchty ◽

Seesandra V. Rajagopala ◽

Peter Uetz

Keyword(s):

Escherichia Coli ◽

Interaction Network ◽

Open Reading Frames ◽

Interaction Patterns ◽

Yeast Two Hybrid ◽

Data Set ◽

Content Type ◽

E Coli ◽

Host Virus Interactions ◽

Two Hybrid

Although most of the 73 open reading frames (ORFs) in bacteriophage λ have been investigated intensively, the function of many genes in host-phage interactions remains poorly understood. Using yeast two-hybrid screens of all lambda ORFs for interactions with its hostEscherichia coli, we determined a raw data set of 631 host-phage interactions resulting in a set of 62 high-confidence interactions after multiple rounds of retesting. These links suggest novel regulatory interactions between theE. colitranscriptional network and lambda proteins. Targeted host proteins and genes required for lambda infection are enriched among highly connected proteins, suggesting that bacteriophages resemble interaction patterns of human viruses. Lambda tail proteins interact with both bacterial fimbrial proteins andE. coliproteins homologous to other phage proteins. Lambda appears to dramatically differ from other phages, such as T7, because of its unusually large number of modified and processed proteins, which reduces the number of host-virus interactions detectable by yeast two-hybrid screens.

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Identification of Coli Surface Antigen 23, a Novel Adhesin of Enterotoxigenic Escherichia coli

Infection and Immunity ◽

10.1128/iai.00263-12 ◽

2012 ◽

Vol 80 (8) ◽

pp. 2791-2801 ◽

Cited By ~ 27

Author(s):

Felipe Del Canto ◽

Douglas J. Botkin ◽

Patricio Valenzuela ◽

Vsevolod Popov ◽

Fernando Ruiz-Perez ◽

...

Keyword(s):

Escherichia Coli ◽

Surface Antigen ◽

Open Reading Frames ◽

Enterotoxigenic Escherichia Coli ◽

Content Type ◽

E Coli ◽

Adhesion Ability ◽

Geographical Regions ◽

Structural Subunit ◽

Pilin Protein

ABSTRACTEnterotoxigenicEscherichia coli(ETEC) is an important cause of diarrhea, mainly in developing countries. Although there are 25 different ETEC adhesins described in strains affecting humans, between 15% and 50% of the clinical isolates from different geographical regions are negative for these adhesins, suggesting that additional unidentified adhesion determinants might be present. Here, we report the discovery of Coli Surface Antigen 23 (CS23), a novel adhesin expressed by an ETEC serogroup O4 strain (ETEC 1766a), which was negative for the previously known ETEC adhesins, albeit it has the ability to adhere to Caco-2 cells. CS23 is encoded by an 8.8-kb locus which contains 9 open reading frames (ORFs), 7 of them sharing significant identity with genes required for assembly of K88-related fimbriae. This gene locus, namedaal(adhesion-associatedlocus), is required for the adhesion ability of ETEC 1766a and was able to confer this adhesive phenotype to a nonadherentE. coliHB101 strain. The CS23 major structural subunit, AalE, shares limited identity with known pilin proteins, and it is more closely related to the CS13 pilin protein CshE, carried by human ETEC strains. Our data indicate that CS23 is a new member of the diverse adhesin repertoire used by ETEC strains.

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Isolation of a Gene Responsible for the Oxidation oftrans-Anethole topara-Anisaldehyde by Pseudomonas putida JYR-1 and Its Expression in Escherichia coli

Applied and Environmental Microbiology ◽

10.1128/aem.00781-12 ◽

2012 ◽

Vol 78 (15) ◽

pp. 5238-5246 ◽

Cited By ~ 9

Author(s):

Dongfei Han ◽

Ji-Young Ryu ◽

Robert A. Kanaly ◽

Hor-Gil Hur

Keyword(s):

Escherichia Coli ◽

Pseudomonas Putida ◽

Hypothetical Protein ◽

Aldehyde Group ◽

Agrobacterium Vitis ◽

T7 Promoter ◽

Content Type ◽

E Coli ◽

Cell Extracts ◽

Isoeugenol Monooxygenase

ABSTRACTA plasmid, pTA163, inEscherichia colicontained an approximately 34-kb gene fragment fromPseudomonas putidaJYR-1 that included the genes responsible for the metabolism oftrans-anethole to protocatechuic acid. Three Tn5-disrupted open reading frame 10 (ORF 10) mutants of plasmid pTA163 lost their abilities to catalyzetrans-anethole. Heterologously expressed ORF 10 (1,047 nucleotides [nt]) under a T7 promoter inE. colicatalyzed oxidative cleavage of a propenyl group oftrans-anethole to an aldehyde group, resulting in the production ofpara-anisaldehyde, and this gene was designatedtao(trans-anetholeoxygenase). The deduced amino acid sequence of TAO had the highest identity (34%) to a hypothetical protein ofAgrobacterium vitisS4 and likely contained a flavin-binding site. Preferred incorporation of an oxygen molecule from water intop-anisaldehyde using18O-labeling experiments indicated stereo preference of TAO for hydrolysis of the epoxide group. Interestingly, unlike the narrow substrate range of isoeugenol monooxygenase fromPseudomonas putidaIE27 andPseudomonas nitroreducensJin1, TAO fromP. putidaJYR-1 catalyzed isoeugenol,O-methyl isoeugenol, and isosafrole, all of which contain the 2-propenyl functional group on the aromatic ring structure. Addition of NAD(P)H to the ultrafiltered cell extracts ofE. coli(pTA163) increased the activity of TAO. Due to the relaxed substrate range of TAO, it may be utilized for the production of various fragrance compounds from plant phenylpropanoids in the future.

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Autotransporter Protein-Encoding Genes of Diarrheagenic Escherichia coli Are Found in both Typical and Atypical Enteropathogenic E. coli Strains

Applied and Environmental Microbiology ◽

10.1128/aem.02635-12 ◽

2012 ◽

Vol 79 (1) ◽

pp. 411-414 ◽

Cited By ~ 21

Author(s):

Afonso G. Abreu ◽

Vanessa Bueris ◽

Tatiane M. Porangaba ◽

Marcelo P. Sircili ◽

Fernando Navarro-Garcia ◽

...

Keyword(s):

Escherichia Coli ◽

Content Type ◽

E Coli ◽

Diarrheagenic Escherichia Coli ◽

Virulence Markers ◽

Protein Encoding ◽

Encoding Genes ◽

Specific Virulence

ABSTRACTAutotransporter (AT) protein-encoding genes of diarrheagenicEscherichia coli(DEC) pathotypes (cah,eatA,ehaABCDJ,espC,espI,espP,pet,pic,sat, andtibA) were detected in typical and atypical enteropathogenicE. coli(EPEC) in frequencies between 0.8% and 39.3%. Although these ATs have been described in particular DEC pathotypes, their presence in EPEC indicates that they should not be considered specific virulence markers.

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A High-Throughput Approach To Identify Compounds That Impair Envelope Integrity in Escherichia coli

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00537-16 ◽

2016 ◽

Vol 60 (10) ◽

pp. 5995-6002 ◽

Cited By ~ 7

Author(s):

Kristin R. Baker ◽

Bimal Jana ◽

Henrik Franzyk ◽

Luca Guardabassi

Keyword(s):

Escherichia Coli ◽

High Throughput ◽

High Throughput Screening ◽

Gram Negative Bacteria ◽

Chromogenic Substrate ◽

Intrinsic Resistance ◽

Gram Negative ◽

Content Type ◽

E Coli ◽

Screening Platform

ABSTRACTThe envelope of Gram-negative bacteria constitutes an impenetrable barrier to numerous classes of antimicrobials. This intrinsic resistance, coupled with acquired multidrug resistance, has drastically limited the treatment options against Gram-negative pathogens. The aim of the present study was to develop and validate an assay for identifying compounds that increase envelope permeability, thereby conferring antimicrobial susceptibility by weakening of the cell envelope barrier in Gram-negative bacteria. A high-throughput whole-cell screening platform was developed to measureEscherichia colienvelope permeability to a β-galactosidase chromogenic substrate. The signal produced by cytoplasmic β-galactosidase-dependent cleavage of the chromogenic substrate was used to determine the degree of envelope permeabilization. The assay was optimized by using known envelope-permeabilizing compounds andE. coligene deletion mutants with impaired envelope integrity. As a proof of concept, a compound library comprising 36 peptides and 45 peptidomimetics was screened, leading to identification of two peptides that substantially increased envelope permeability. Compound 79 reduced significantly (from 8- to 125-fold) the MICs of erythromycin, fusidic acid, novobiocin and rifampin and displayed synergy (fractional inhibitory concentration index, <0.2) with these antibiotics by checkerboard assays in two genetically distinctE. colistrains, including the high-risk multidrug-resistant, CTX-M-15-producing sequence type 131 clone. Notably, in the presence of 0.25 μM of this peptide, both strains were susceptible to rifampin according to the resistance breakpoints (R> 0.5 μg/ml) for Gram-positive bacterial pathogens. The high-throughput screening platform developed in this study can be applied to accelerate the discovery of antimicrobial helper drug candidates and targets that enhance the delivery of existing antibiotics by impairing envelope integrity in Gram-negative bacteria.

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A Rhodobacter sphaeroides Protein Mechanistically Similar to Escherichia coli DksA Regulates Photosynthetic Growth

mBio ◽

10.1128/mbio.01105-14 ◽

2014 ◽

Vol 5 (3) ◽

Cited By ~ 7

Author(s):

Christopher W. Lennon ◽

Kimberly C. Lemmer ◽

Jessica L. Irons ◽

Max I. Sellman ◽

Timothy J. Donohue ◽

...

Keyword(s):

Escherichia Coli ◽

Structure Function ◽

Rhodobacter Sphaeroides ◽

Fatty Acid Content ◽

Regulatory Protein ◽

Growth Conditions ◽

Globular Domain ◽

Content Type ◽

E Coli

ABSTRACTDksA is a global regulatory protein that, together with the alarmone ppGpp, is required for the “stringent response” to nutrient starvation in the gammaproteobacteriumEscherichia coliand for more moderate shifts between growth conditions. DksA modulates the expression of hundreds of genes, directly or indirectly. Mutants lacking a DksA homolog exhibit pleiotropic phenotypes in other gammaproteobacteria as well. Here we analyzed the DksA homolog RSP2654 in the more distantly relatedRhodobacter sphaeroides, an alphaproteobacterium. RSP2654 is 42% identical and similar in length toE. coliDksA but lacks the Zn finger motif of theE. coliDksA globular domain. Deletion of the RSP2654 gene results in defects in photosynthetic growth, impaired utilization of amino acids, and an increase in fatty acid content. RSP2654 complements the growth and regulatory defects of anE. colistrain lacking thedksAgene and modulates transcriptionin vitrowithE. coliRNA polymerase (RNAP) similarly toE. coliDksA. RSP2654 reduces RNAP-promoter complex stabilityin vitrowith RNAPs fromE. coliorR. sphaeroides, alone and synergistically with ppGpp, suggesting that even though it has limited sequence identity toE. coliDksA (DksAEc), it functions in a mechanistically similar manner. We therefore designate the RSP2654 protein DksARsp. Our work suggests that DksARsphas distinct and important physiological roles in alphaproteobacteria and will be useful for understanding structure-function relationships in DksA and the mechanism of synergy between DksA and ppGpp.IMPORTANCEThe role of DksA has been analyzed primarily in the gammaproteobacteria, in which it is best understood for its role in control of the synthesis of the translation apparatus and amino acid biosynthesis. Our work suggests that DksA plays distinct and important physiological roles in alphaproteobacteria, including the control of photosynthesis inRhodobacter sphaeroides. The study of DksARsp, should be useful for understanding structure-function relationships in the protein, including those that play a role in the little-understood synergy between DksA and ppGpp.

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Vibrio cholerae Triggers SOS and Mutagenesis in Response to a Wide Range of Antibiotics: a Route towards Multiresistance

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01549-10 ◽

2011 ◽

Vol 55 (5) ◽

pp. 2438-2441 ◽

Cited By ~ 107

Author(s):

Zeynep Baharoglu ◽

Didier Mazel

Keyword(s):

Escherichia Coli ◽

Antibiotic Resistance ◽

Vibrio Cholerae ◽

Fluorescent Protein ◽

Resistance Development ◽

Content Type ◽

E Coli ◽

Wide Range ◽

Green Fluorescent ◽

Regulated Promoters

ABSTRACTAntibiotic resistance development has been linked to the bacterial SOS stress response. InEscherichia coli, fluoroquinolones are known to induce SOS, whereas other antibiotics, such as aminoglycosides, tetracycline, and chloramphenicol, do not. Here we address whether various antibiotics induce SOS inVibrio cholerae. Reporter green fluorescent protein (GFP) fusions were used to measure the response of SOS-regulated promoters to subinhibitory concentrations of antibiotics. We show that unlike the situation withE. coli, all these antibiotics induce SOS inV. cholerae.

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