scholarly journals Identification and Characterization ofaarF, a Locus Required for Production of Ubiquinone inProvidencia stuartii and Escherichia coli and for Expression of 2′-N-Acetyltransferase inP. stuartii

1998 ◽  
Vol 180 (1) ◽  
pp. 128-135 ◽  
Author(s):  
David R. Macinga ◽  
Gregory M. Cook ◽  
Robert K. Poole ◽  
Philip N. Rather
Keyword(s):  
Escherichia Coli ◽  
Regulation Of Gene Expression ◽  
Open Reading Frames ◽  
Mrna Levels ◽  
E Coli ◽  
Providencia Stuartii ◽  
High Level ◽  
Identification And Characterization ◽  
Reading Frames ◽  
Level Resistance

ABSTRACT Providencia stuartii contains a chromosomal 2′-N-acetyltransferase [AAC(2′)-Ia] involved in the O acetylation of peptidoglycan. The AAC(2′)-Ia enzyme is also capable of acetylating and inactivating certain aminoglycosides and confers high-level resistance to these antibiotics when overexpressed. We report the identification of a locus in P. stuartii, designated aarF, that is required for the expression of AAC(2′)-Ia. Northern (RNA) analysis demonstrated thataac(2′)-Ia mRNA levels were dramatically decreased in aP. stuartii strain carrying anaarF::Cm disruption. TheaarF::Cm disruption also resulted in a deficiency in the respiratory cofactor ubiquinone. The aarF locus encoded a protein that had a predicted molecular mass of 62,559 Da and that exhibited extensive amino acid similarity to the products of two adjacent open reading frames of unknown function (YigQ and YigR), located at 86 min on the Escherichia coli chromosome. AnE. coli yigR::Kan mutant was also deficient in ubiquinone content. Complementation studies demonstrated that theaarF and the E. coli yigQR loci were functionally equivalent. The aarF or yigQRgenes were unable to complement ubiD and ubiEmutations that are also present at 86 min on the E. colichromosome. This result indicates that aarF(yigQR) represents a novel locus for ubiquinone production and reveals a previously unreported connection between ubiquinone biosynthesis and the regulation of gene expression.

scholarly journals Identification and Characterization of the Locus for Diffuse Adherence, Which Encodes a Novel Afimbrial Adhesin Found in Atypical Enteropathogenic Escherichia coli

2005 ◽  
Vol 73 (8) ◽  
pp. 4753-4765 ◽  
Author(s):  
Isabel C. A. Scaletsky ◽  
Jane Michalski ◽  
Alfredo G. Torres ◽  
Michelle V. Dulguer ◽  
James B. Kaper
Keyword(s):  
Escherichia Coli ◽  
Genomic Region ◽  
Open Reading Frames ◽  
E Coli ◽  
Atypical Epec ◽  
Structural Subunit ◽  
K 12 ◽  
Identification And Characterization ◽  
Reading Frames

ABSTRACT The O26 serogroup of enteropathogenic Escherichia coli (EPEC) is one of the serogroups most frequently implicated in infant diarrhea and is also common among enterohemorrhagic E. coli (EHEC) strains. The most common O26 strains belong to EPEC/EHEC serotype O26:H11 and are generally Shiga toxin (Stx) positive. Stx-negative E. coli strains that are negative for the EPEC EAF plasmid and bundle-forming pilus (Bfp) are classified as atypical EPEC. Here, we report a novel adhesin present in an stx-negative bfpA-negative atypical EPEC O26:H11 strain isolated from an infant with diarrhea. A cloned 15-kb genomic region from this strain, designated the locus for diffuse adherence (lda), confers diffuse adherence on HEp-2 cells when expressed in E. coli K-12. Sequence analysis of lda revealed a G+C content of 46.8% and 15 open reading frames sharing homology with the E. coli K88 fae and CS31A clp fimbrial operons. The lda region is part of a putative 26-kb genomic island inserted into the proP gene of the E. coli chromosome. Hybridization studies have demonstrated the prevalence of the minor structural subunit gene, ldaH, across E. coli serogroups O5, O26, O111, and O145. A second plasmid-encoded factor that contributed to the Hep-2 adherence of this strain was also identified but was not characterized. Null mutations that abolish adherence to HEp-2 cells can be restored by plasmid complementation. Antiserum raised against the major structural subunit, LdaG, recognizes a 25-kDa protein from crude heat-extracted protein preparations and inhibits the adherence of the E. coli DH5α lda + clone to HEp-2 cells. Electron microscopy revealed a nonfimbrial structure surrounding the bacterial cell.

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

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.

scholarly journals A Stress-Induced Bias in the Reading of the Genetic Code in Escherichia coli

mBio ◽  
2016 ◽  
Vol 7 (6) ◽  
Author(s):  
Adi Oron-Gottesman ◽  
Martina Sauert ◽  
Isabella Moll ◽  
Hanna Engelberg-Kulka
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Ribosomal Protein ◽  
Genetic Code ◽  
Open Reading Frames ◽  
Translation Machinery ◽  
E Coli ◽  
Universal Characteristic ◽  
Living Organisms ◽  
Reading Frames

ABSTRACT Escherichia coli mazEF is an extensively studied stress-induced toxin-antitoxin (TA) system. The toxin MazF is an endoribonuclease that cleaves RNAs at ACA sites. Thereby, under stress, the induced MazF generates a stress-induced translation machinery (STM), composed of MazF-processed mRNAs and selective ribosomes that specifically translate the processed mRNAs. Here, we further characterized the STM system, finding that MazF cleaves only ACA sites located in the open reading frames of processed mRNAs, while out-of-frame ACAs are resistant. This in-frame ACA cleavage of MazF seems to depend on MazF binding to an extracellular-death-factor (EDF)-like element in ribosomal protein bS1 (bacterial S1), apparently causing MazF to be part of STM ribosomes. Furthermore, due to the in-frame MazF cleavage of ACAs under stress, a bias occurs in the reading of the genetic code causing the amino acid threonine to be encoded only by its synonym codon ACC, ACU, or ACG, instead of by ACA. IMPORTANCE The genetic code is a universal characteristic of all living organisms. It defines the set of rules by which nucleotide triplets specify which amino acid will be incorporated into a protein. Our results represent the first existing report on a stress-induced bias in the reading of the genetic code. We found that in E. coli , under stress, the amino acid threonine is encoded only by its synonym codon ACC, ACU, or ACG, instead of by ACA. This is because under stress, MazF generates a stress-induced translation machinery (STM) in which MazF cleaves in-frame ACA sites of the processed mRNAs.

scholarly journals Outbreak Caused by NDM-1- and RmtB-Producing Escherichia coli in Bulgaria

2014 ◽  
Vol 58 (4) ◽  
pp. 2472-2474 ◽  
Author(s):  
Laurent Poirel ◽  
Encho Savov ◽  
Arzu Nazli ◽  
Angelina Trifonova ◽  
Iva Todorova ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
16S Rrna ◽  
Sequence Type ◽  
Content Type ◽  
E Coli ◽  
Carbapenem Resistant ◽  
The World ◽  
High Level ◽  
16S Rrna Methylase ◽  
Level Resistance

ABSTRACTTwelve consecutive carbapenem-resistantEscherichia coliisolates were recovered from patients (infection or colonization) hospitalized between March and September 2012 in different units at a hospital in Bulgaria. They all produced the carbapenemase NDM-1 and the extended-spectrum-β-lactamase CTX-M-15, together with the 16S rRNA methylase RmtB, conferring high-level resistance to all aminoglycosides. All those isolates were clonally related and belonged to the same sequence type, ST101. In addition to being the first to identify NDM-producing isolates in Bulgaria, this is the very first study reporting an outbreak of NDM-1-producingE. coliin the world.

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 Plasmid-Mediated Resistance to Extended-Spectrum Cephalosporins and Resistance to Fluoroquinolones in Escherichia Coli Isolates from Black-headed Gulls (Larus Ridibundus)

2021 ◽  
Author(s):  
Maja Velhner ◽  
Dalibor Todorović ◽  
Katarina Novović ◽  
Branko Jovčić ◽  
Gospava Lazić ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
E Coli ◽  
Extended Spectrum ◽  
Cephalosporin Antibiotics ◽  
High Level ◽  
Group D ◽  
Sequence Types ◽  
Replicon Type ◽  
Level Resistance ◽  
Game Animals

Abstract Although resistance to fluoroquinolones is common in E. coli isolates from farm and game animals in Serbia, currently no data are accessible on the occurrence of antibacterial resistances in E. coli isolates from gulls. Therefore, 45 cloacal swabs and 50 fecal samples from black-headed gulls were investigated for the presence of Escherichia coli isolates resistant to antibiotics. Multidrug resistance was detected in 22 E. coli isolates. High level resistance to fluoroquinolones was found in ten isolates with MIC values of ciprofloxacin ranging from 4 to 32 mg/L. Genotyping revealed single or double mutations in the quinolone resistance determining region (QRDR) of the gyrA or gyrA, parC and parE genes, respectively. Ten isolates showed resistance to extended-spectrum cephalosporin antibiotics. These ten isolates belonged to phylogenetic group B2 (five isolates), group D (four isolates) and group B1 (one isolate). An extended-spectrum β-lactamase resistance phenotype was detected in one isolate which carried the blaCTX-M-1 gene on a plasmid of the I2/FIB replicon type. Nine isolates carried blaCMY-2 genes, which were detected on conjugative plasmids in seven isolates. One transconjugant also carried hly, iroN, iss, ompT and cvaC virulence genes on the plasmid. Five different sequence types (ST38, ST2307, ST224, ST162 and ST34) were detected in E. coli isolates with ESBL or AmpC phenotype and genotype.

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 Human isolates of apramycin-resistant Escherichia coli which contain the genes for the AAC(3)IV enzyme

1993 ◽  
Vol 110 (2) ◽  
pp. 253-259 ◽  
Author(s):  
J. E. B. Hunter ◽  
C. A. Hart ◽  
J. C. Shelley ◽  
J. R. Walton ◽  
M. Bennett
Keyword(s):  
Escherichia Coli ◽  
Minimal Inhibitory Concentration ◽  
Inhibitory Concentration ◽  
Aminoglycoside Antibiotic ◽  
Dna Probe ◽  
Conjugative Plasmid ◽  
E Coli ◽  
High Level ◽  
Level Resistance

SUMMARYGentamicin-resistant Escherichia coli isolated at different periods from patients in two hospitals were tested for resistance to the aminoglycoside antibiotic apramycin. Twenty-four of 93 (26%) gentamicin-resistant isolates collected from the Royal Liverpool Hospital between 1981 and 1990 were resistant to apramycin. Thirteen isolates were highly resistant to apramycin (minimal inhibitory concentration (MIC) ≥ 1024 μg/ml). were also resistant to gentamicin, netilmicin and tobramycin, and hybridized with a DNA probe derived from the aminoglycoside acetyltransferase (3)IV (AAC(3)IV) gene. The proportion of gentamicinresistant isolates which had high level resistance to apramycin increased from 7% in 1981–5 to 24% in 1986–90.Twelve gentamicin-resistant E. coli from Guy's and St Thomas's Hospital isolated between 1977 and 1980 were also tested for resistance to apramycin. For five of these isolates the MICs of apramycin was 32–256 μg/ml. None was shown to have a conjugative plasmid carrying resistance to apramycin and only one hybridized with the DNA probe for the AAC(3)IV enzyme.

scholarly journals Synthesis of a Klebsiella pneumoniae O-Antigen Heteropolysaccharide (O12) Requires an ABC 2 Transporter

2003 ◽  
Vol 185 (5) ◽  
pp. 1634-1641 ◽  
Author(s):  
Luis Izquierdo ◽  
Susana Merino ◽  
Miguel Regué ◽  
Florencia Rodriguez ◽  
Juan M. Tomás
Keyword(s):  
Klebsiella Pneumoniae ◽  
Genomic Library ◽  
Gene Clusters ◽  
Open Reading Frames ◽  
Complete Analysis ◽  
E Coli ◽  
O Antigen ◽  
High Level ◽  
K 12 ◽  
Reading Frames

ABSTRACT A recombinant clone encoding enzymes for Klebsiella pneumoniae O12-antigen lipopolysaccharide (LPS) was found when we screened for serum resistance of a cosmid-based genomic library of K. pneumoniae KT776 (O12:K80) introduced into Escherichia coli DH5α. A total of eight open reading frames (ORFs) (wb O12 gene cluster) were necessary to produce K. pneumoniae O12-antigen LPS in E. coli K-12. A complete analysis of the K. pneumoniae wb O12 cluster revealed an interesting coincidence with the wb O4 cluster of Serratia marcescens from ORF5 to ORF8 (or WbbL to WbbA). This prompted us to generate mutants of K. pneumoniae strain KT776 (O12) and to study complementation between the two enterobacterial wb clusters using mutants of S. marcescens N28b (O4) obtained previously. Both wb gene clusters are examples of ABC 2 transporter-dependent pathways for O-antigen heteropolysaccharides. The wzm-wzt genes and the wbbA or wbbB genes were not interchangeable between the two gene clusters despite their high level of similarity. However, introduction of three cognate genes (wzm-wzt-wbbA or wzm-wzt-wbbB) into mutants unable to produce O antigen allowed production of the specific O antigen. The K. pneumoniae O12 WbbL protein performs the same function as WbbL from S. marcescens O4 in either the S. marcescens O4 or E. coli K-12 genetic background.

scholarly journals Identification of FosA8, a Plasmid-Encoded Fosfomycin Resistance Determinant from Escherichia coli, and Its Origin in Leclercia adecarboxylata

2019 ◽  
Vol 63 (11) ◽  
Author(s):  
Laurent Poirel ◽  
Xavier Vuillemin ◽  
Nicolas Kieffer ◽  
Linda Mueller ◽  
Marie-Christine Descombes ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Amino Acid Identity ◽  
Natural Resistance ◽  
Whole Genome ◽  
Content Type ◽  
Acid Identity ◽  
E Coli ◽  
Fosfomycin Resistance ◽  
High Level ◽  
Level Resistance

ABSTRACT A plasmid-located fosfomycin resistance gene, fosA8, was identified from a CTX-M-15-producing Escherichia coli isolate recovered from urine. Identification of this gene was obtained by whole-genome sequencing. It encoded FosA8, which shares 79% and 78% amino acid identity with the most closely related FosA2 and FosA1 enzymes, respectively. The fosA8 gene was located on a transferable 50-kb plasmid of IncN type encoding high-level resistance to fosfomycin. In silico analysis and cloning experiments identified fosA8 analogues (99% identity) in the genome of Leclercia decarboxylata, which is an enterobacterial species with natural resistance to fosfomycin. This finding adds L. decarboxylata to the list of enterobacterial species that are a reservoir of fosA-like genes which have been captured from the chromosome of a progenitor and are then acquired by E. coli.

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