scholarly journals Characterization of the Binding of Diarrheagenic Strains of E. coli to Plant Surfaces and the Role of Curli in the Interaction of the Bacteria with Alfalfa Sprouts

2005 ◽  
Vol 18 (11) ◽  
pp. 1235-1242 ◽  
Author(s):  
Cecelia Jeter ◽  
Ann G. Matthysse
Keyword(s):  
Escherichia Coli ◽  
Arabidopsis Thaliana ◽  
No Reduction ◽  
E Coli ◽  
Diarrheagenic Escherichia Coli ◽  
Alfalfa Sprouts ◽  
Plant Surfaces ◽  
Seed Coats

Diarrheagenic Escherichia coli were able to bind to plant surfaces, including alfalfa sprouts and open seed coats, and tomato and Arabidopsis thaliana seedlings incubated in water. The characteristics of the binding differed with the bacterial strain examined. Laboratory K12 strains of E. coli failed to show significant binding to any of the plant surfaces examined, suggesting that some of the genes present and expressed in pathogenic strains and absent or unexpressed in K12 strains may be required for binding to plants. When a plasmid carrying the mlrA gene (a positive regulator of curli biosynthesis) or a plasmid carrying the operons that encode the synthesis of curli (csgA-G) was introduced into K12 strains, the bacteria acquired the ability to bind to sprouts. CsgA mutants of an avian pathogenic E. coli and an O157:H7 strain showed no reduction in their ability to bind to sprouts. Thus, the production of curli appears to be sufficient to allow K12 strains to bind, but curli are not necessary for the binding of pathogenic strains, suggesting that pathogenic strains may have more than one mechanism for binding to plant surfaces.

scholarly journals Molecular Characterization of Commensal Escherichia coli Adapted to Different Compartments of the Porcine Gastrointestinal Tract

2012 ◽  
Vol 78 (19) ◽  
pp. 6799-6803 ◽  
Author(s):  
Sam Abraham ◽  
David M. Gordon ◽  
James Chin ◽  
Huub J. M. Brouwers ◽  
Peter Njuguna ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Gastrointestinal Tract ◽  
Random Amplified Polymorphic Dna ◽  
Content Type ◽  
E Coli ◽  
Plasmid Replicon ◽  
Different Strains ◽  
Different Characteristics

ABSTRACTThe role ofEscherichia colias a pathogen has been the focus of considerable study, while much less is known about it as a commensal and how it adapts to and colonizes different environmental niches within the mammalian gut. In this study, we characterizeEscherichia coliorganisms (n= 146) isolated from different regions of the intestinal tracts of eight pigs (dueodenum, ileum, colon, and feces). The isolates were typed using the method of random amplified polymorphic DNA (RAPD) and screened for the presence of bacteriocin genes and plasmid replicon types. Molecular analysis of variance using the RAPD data showed thatE. coliisolates are nonrandomly distributed among different gut regions, and that gut region accounted for 25% (P< 0.001) of the observed variation among strains. Bacteriocin screening revealed that a bacteriocin gene was detected in 45% of the isolates, with 43% carrying colicin genes and 3% carrying microcin genes. Of the bacteriocins observed (H47, E3, E1, E2, E7, Ia/Ib, and B/M), the frequency with which they were detected varied with respect to gut region for the colicins E2, E7, Ia/Ib, and B/M. The plasmid replicon typing gave rise to 25 profiles from the 13 Inc types detected. Inc F types were detected most frequently, followed by Inc HI1 and N types. Of the Inc types detected, 7 were nonrandomly distributed among isolates from the different regions of the gut. The results of this study indicate that not only may the different regions of the gastrointestinal tract harbor different strains ofE. colibut also that strains from different regions have different characteristics.

scholarly journals Diarrheagenic Escherichia coli and Acute and Persistent Diarrhea in Returned Travelers

2000 ◽  
Vol 38 (10) ◽  
pp. 3550-3554 ◽  
Author(s):  
C. Schultsz ◽  
J. van den Ende ◽  
F. Cobelens ◽  
T. Vervoort ◽  
A. van Gompel ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Multivariate Analysis ◽  
Acute Diarrhea ◽  
Case Control Study ◽  
Persistent Diarrhea ◽  
E Coli ◽  
Diarrheagenic Escherichia Coli ◽  
Stool Samples ◽  
Control Study

To determine the role of diarrheagenic Escherichia coliin acute and persistent diarrhea in returned travelers, a case control study was performed. Enterotoxigenic E. coli (ETEC) was detected in stool samples from 18 (10.7%) of 169 patients and 4 (3.7%) of 108 controls. Enteroaggregative E. coli (EAggEC) was detected in 16 (9.5%) patients and 7 (6.5%) controls. Diffuse adherent E. coli strains were commonly present in both patients (13%) and controls (13.9). Campylobacter andShigella species were the other bacterial enteropathogens most commonly isolated (10% of patients, 2% of controls). Multivariate analysis showed that the presence of ETEC was associated with acute diarrhea (odds ratio [OR], 6.7; 95% confidence interval [CI], 1.5 to 29.1; P = 0.005), but not with persistent diarrhea (OR, 1.6; 95% CI, 0.4 to 7.4). EAggEC was significantly more often present in patients with acute diarrhea than in controls (P = 0.009), but no significant association remained after multivariate analysis. ETEC and EAggEC are frequently detected in returned travelers with diarrhea. The presence of ETEC strains is associated with acute but not with persistent diarrhea.

Colicinogeny among Escherichia coli Serotypes, Including O157:H7, Representing Four Closely Related Diarrheagenic Clones

1998 ◽  
Vol 61 (11) ◽  
pp. 1431-1438 ◽  
Author(s):  
SHELTON E. MURINDA ◽  
SHU-MIN LIU ◽  
ROBERT F. ROBERTS ◽  
RICHARD A. WILSON
Keyword(s):  
Escherichia Coli ◽  
Toxin Production ◽  
Coli Strain ◽  
The Other ◽  
E Coli ◽  
Diarrheagenic Escherichia Coli ◽  
Reference Set ◽  
Almost All ◽  
Luria Agar

Twenty-seven diarrheagenic Escherichia coli (DEC) strains from five closely related, genetically distinct clones (DEC 3, 4, 8, 9, and 10), representing serotypes commonly associated with Shiga-like toxin production, i.e., 015:H−, 026:(H11, H−), 0111:(H8, H11, H−), and O157:H7, were evaluated for colicinogeny on Luria agar or Luria agar containing 0.25 μg/ml mitomycin C to induce colicin production. Ten (37%) of the DEC strains tested were colicinogenic. One of 11 serotype O157:H7 strains, DEC strain 4E, produced a colicin identified as Col D. DEC strains 8B, 9D, and 10B produced Col E1, whereas DEC strain 10A produced Col E2. DEC strains 8A, 8E, 10C, 10E, and 10F produced “untypable” colicins that killed almost all Pugsley Colicin Reference Set strains and the other DEC strains tested. To aid with further characterization of the colicins, plasmids extracted from each colicin-producing (Col+) DEC strain were used to transform E. coli strain DH5α. All Col+ DH5α transformants contained one plasmid ranging in size from 1.3 to 10 kb. Some transformants were stable colicin producers whereas others were unstable. The inhibitory activity and colicin sensitivity and insensitivity profiles of the Col+ transformants were similar to those of the corresponding Col+ donor DEC strains. It appears that the untypable colicins are novel and, thus, warrant further study. Colicin production by some of the DEC strains evaluated partly explains why they were insensitive to standard colicins in a previous study.

scholarly journals Molecular and phenotypic characterization of diarrheagenic Escherichia coli isolated from groundwater in rural areas in southern Brazil

2019 ◽  
Vol 17 (4) ◽  
pp. 597-608
Author(s):  
Caroline Rodrigues da Silva ◽  
Matheus Silva Sanches ◽  
Kawana Hiromori Macedo ◽  
Angélica Marim Lopes Dambrozio ◽  
Sergio Paulo Dejato da Rocha ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Rural Areas ◽  
Microbiological Quality ◽  
Vero Cells ◽  
Phenotypic Characterization ◽  
Human Consumption ◽  
E Coli ◽  
Diarrheagenic Escherichia Coli ◽  
Quality Of Water

Abstract Water-borne diseases like diarrheagenic Escherichia coli (DEC)-induced gastroenteritis are major public health problems in developing countries. In this study, the microbiological quality of water from mines and shallow wells was analyzed for human consumption. Genotypic and phenotypic characterization of DEC strains was performed. A total of 210 water samples was analyzed, of which 153 (72.9%) contained total coliforms and 96 (45.7%) E. coli. Of the E. coli isolates, 27 (28.1%) contained DEC genes. The DEC isolates included 48.1% Shiga toxin-producing E. coli (STEC), 29.6% enteroaggregative E. coli (EAEC), 14.9% enteropathogenic E. coli (EPEC), 3.7% enterotoxigenic E. coli (ETEC), and 3.7% enteroinvasive E. coli (EIEC). All the STECs had cytotoxic effects on Vero cells and 14.8% of the DEC isolates were resistant to at least one of the antibiotics tested. All DEC formed biofilms and 92.6% adhered to HEp-2 cells with a prevalence of aggregative adhesion (74%). We identified 25 different serotypes. One EPEC isolate was serotype O44037:H7, reported for the first time in Brazil. Phylogenetically, 63% of the strains belonged to group B1. The analyzed waters were potential reservoirs for DEC and could act as a source for infection of humans. Preventive measures are needed to avoid such contamination.

scholarly journals Differential Binding of Escherichia coli O157:H7 to Alfalfa, Human Epithelial Cells, and Plastic Is Mediated by a Variety of Surface Structures

2005 ◽  
Vol 71 (12) ◽  
pp. 8008-8015 ◽  
Author(s):  
Alfredo G. Torres ◽  
Cecelia Jeter ◽  
William Langley ◽  
Ann G. Matthysse
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
Food Poisoning ◽  
The United States ◽  
Surface Proteins ◽  
E Coli ◽  
Alfalfa Sprouts ◽  
K 12 ◽  
Plant Surfaces

ABSTRACT Escherichia coli O157:H7 carried on plant surfaces, including alfalfa sprouts, has been implicated in food poisoning and outbreaks of disease in the United States. Adhesion to cell surfaces is a key component for bacterial establishment and colonization on many types of surfaces. Several E. coli O157:H7 surface proteins are thought to be important for adhesion and/or biofilm formation. Therefore, we examined whether mutations in several genes encoding potential adhesins and regulators of adherence have an effect on bacterial binding to plants and also examined the role of these genes during adhesion to Caco-2 cells and during biofilm formation on plastic in vitro. The genes tested included those encoding adhesins (cah, aidA1, and ompA) and mediators of hyperadherence (tdcA, yidE, waaI, and cadA) and those associated with fimbria formation (csgA, csgD, and lpfD2). The introduction of some of these genes (cah, aidA1, and csg loci) into an E. coli K-12 strain markedly increased its ability to bind to alfalfa sprouts and seed coats. The addition of more than one of these genes did not show an additive effect. In contrast, deletion of one or more of these genes in a strain of E. coli O157:H7 did not affect its ability to bind to alfalfa. Only the absence of the ompA gene had a significant effect on binding, and the plant-bacterium interaction was markedly reduced in a tdcA ompA double mutant. In contrast, the E. coli O157:H7 ompA and tdcA ompA mutant strains were only slightly affected in adhesion to Caco-2 cells and during biofilm formation. These findings suggest that some adhesins alone are sufficient to promote binding to alfalfa and that they may exist in E. coli O157:H7 as redundant systems, allowing it to compensate for the loss of one or more of these systems. Binding to the three types of surfaces appeared to be mediated by overlapping but distinct sets of genes. The only gene which appeared to be irreplaceable for binding to plant surfaces was ompA.

Effect of alteration of translation error rate on enzyme microheterogeneity as assessed by variation in single molecule electrophoretic mobility and catalytic activity

2009 ◽  
Vol 87 (3) ◽  
pp. 517-529 ◽  
Author(s):  
Ellert R. Nichols ◽  
Elnaz Shadabi ◽  
Douglas B. Craig
Keyword(s):  
Escherichia Coli ◽  
Catalytic Activity ◽  
Single Molecule ◽  
Hydrodynamic Radius ◽  
No Reduction ◽  
E Coli ◽  
Translation Error ◽  
Enzyme Molecules ◽  
Catalytic Heterogeneity

The role of translation error for Escherichia coli individual β-galactosidase molecule catalytic and electrophoretic heterogeneity was investigated using CE-LIF. An E. coli rpsL mutant with a hyperaccurate translation phenotype produced enzyme molecules that exhibited significantly less catalytic heterogeneity but no reduction of electrophoretic heterogeneity. Enzyme expressed with streptomycin-induced translation error had increased thermolability, lower activity, and no significant change to catalytic or electrophoretic heterogeneity. Modeling of the electrophoretic behaviour of β-galactosidase suggested that variation of the hydrodynamic radius may be the most significant contributor to electrophoretic heterogeneity.

scholarly journals Isolation of PDX2, a Second Novel Gene in the Pyridoxine Biosynthesis Pathway of Eukaryotes, Archaebacteria, and a Subset of Eubacteria

2001 ◽  
Vol 183 (11) ◽  
pp. 3383-3390 ◽  
Author(s):  
Marilyn Ehrenshaft ◽  
Margaret E. Daub
Keyword(s):  
Escherichia Coli ◽  
Gene Replacement ◽  
Degenerate Primer ◽  
Biosynthesis Pathway ◽  
Protein Motifs ◽  
E Coli ◽  
Biosynthesis Gene ◽  
Targeted Gene Replacement

ABSTRACT In this paper we describe the isolation of a second gene in the newly identified pyridoxine biosynthesis pathway of archaebacteria, some eubacteria, fungi, and plants. Although pyridoxine biosynthesis has been thoroughly examined in Escherichia coli, recent characterization of the Cercospora nicotianae biosynthesis gene PDX1 led to the discovery that most organisms contain a pyridoxine synthesis gene not found in E. coli. PDX2was isolated by a degenerate primer strategy based on conserved sequences of a gene specific to PDX1-containing organisms. The role of PDX2 in pyridoxine biosynthesis was confirmed by complementation of two C. nicotianae pyridoxine auxotrophs not mutant in PDX1. Also, targeted gene replacement of PDX2 in C. nicotianae results in pyridoxine auxotrophy. Comparable to PDX1, PDX2 homologues are not found in any of the organisms with homologues to theE. coli pyridoxine genes, but are found in the same archaebacteria, eubacteria, fungi, and plants that containPDX1 homologues. PDX2 proteins are less well conserved than their PDX1 counterparts but contain several protein motifs that are conserved throughout all PDX2 proteins.

scholarly journals Construction and Characterization of an Isogenicslt-ii Deletion Mutant of EnterohemorrhagicEscherichia coli

1998 ◽  
Vol 66 (5) ◽  
pp. 2337-2341 ◽  
Author(s):  
Florian Gunzer ◽  
Ursula Bohn ◽  
Sibylle Fuchs ◽  
Inge Mühldorfer ◽  
Jörg Hacker ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Deletion Mutant ◽  
Protein Synthesis Inhibitors ◽  
Course Of Disease ◽  
E Coli ◽  
Suicide Vector ◽  
Derivatives Of ◽  
Negative Mutant

ABSTRACT Enterohemorrhagic Escherichia coli (EHEC) produces Shiga-like toxins (SLT), potent protein synthesis inhibitors. To further dissect the role of SLT-II in the course of disease, we have constructed E. coli TUV86-2, an isogenic SLT-II-negative mutant of EHEC strain 86-24. The slt-ii gene was inactivated by suicide vector mutagenesis. We also isolated derivatives of strain 86-24 that were cured of the phage carrying the toxin genes.

Cloning and characterization of a cDNA encoding serine palmitoyltransferase in Arabidopsis thaliana

2000 ◽  
Vol 28 (6) ◽  
pp. 745-747 ◽  
Author(s):  
K. Tamura ◽  
H. Nishiura ◽  
J. Mori ◽  
H. Imai
Keyword(s):  
Escherichia Coli ◽  
Arabidopsis Thaliana ◽  
Cdna Clone ◽  
De Novo ◽  
Lipid Synthesis ◽  
Serine Palmitoyltransferase ◽  
Functional Identification ◽  
E Coli ◽  
Significant Production

The first and committed step in de novo sphingo-lipid synthesis is catalysed by serine palmitoyl-transferase (EC 2.3.1.50), which condenses serine and palmitoyl-CoA to form 3-ketosphinganine in a pyridoxal-5Î-phosphate-dependent reaction. We have isolated and characterized a cDNA clone from Arabidopsis thaliana that is homologous to yeast and mammalian LCB2. For a functional identification, the A. thaliana homologous cDNA was expressed in Escherichia coli which resulted in significant production of new sphinganine in E. coli cells.

scholarly journals Characterization of Diarrheagenic Escherichia Coli Strains Isolated from Slaughtered Sheep in México

2021 ◽  
Author(s):  
Jorge Acosta-Dibarrat ◽  
Edgar Enriquez-Gómez ◽  
Martín Talavera-Rojas ◽  
Edgardo Soriano-Vargas ◽  
Armando Navarro ◽  
...  
Keyword(s):  
Public Health ◽  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Central Region ◽  
Shiga Toxin ◽  
E Coli ◽  
Diarrheagenic Escherichia Coli ◽  
Food Borne ◽  
Almost All

Abstract Sheep represent one of the main reservoirs of diarrheagenic Escherichia coli; this microorganism is an etiological agent of food-borne diseases, therefore, this work aimed to identify and characterize the principal pathotypes of diarrheagenic E. coli obtained through rectal swabs and samples from sheep carcasses slaughtered in an abattoir at the central region of Mexico. The isolates were subjected to bacteriological identification, serotyping; phylogenetic classification; detection for virulence factors, and antimicrobial sensibility. A total of 90 E. coli isolates were obtained, diarrheagenic serotypes with health public relevance were found: O76:H19 (5), O146:H21 (3), O91:H10 (2), O6:NM (1), and O8:NM (1). According to pathotype, 47.7% of total isolates were Shiga toxin-producing E. coli, while 3.3% were enteropathogenic, 2.2% enterotoxigenic, and 1.1% enteroinvasive E. coli; the remaining isolates did not express the genes used to assign them to some pathotype. Regarding the Shiga toxin subtypes, 31/43 (72.09%) were cataloged as stx1c, 11/43 (25.5%), stx1a- stx1c and 1/43 (2.3%) stx1a- stx1d; while for stx2 it was possible identify stx2g 4/7(57.14%), stx2b 1/7 (14.7%) and stx2b-stx2g 2/7 (28.5%). Almost all pathotypes (91–100%) belonged to phylogroup B1. Furthermore, it was observed that the 90 isolates showed an antimicrobial resistance of 100% to nitrofurantoin, followed by ampicillin, tetracycline, and trimethoprim-sulfamethoxazole. These results highlight the importance of diarrheagenic E. coli as a potential risk for public health during the slaughtering process.

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