scholarly journals Development of a Biofilm Production-Deficient Escherichia coli Strain as a Host for Biotechnological Applications

2006 ◽  
Vol 72 (5) ◽  
pp. 3336-3342 ◽  
Author(s):  
Bong Hyun Sung ◽  
Choong Hoon Lee ◽  
Byung Jo Yu ◽  
Jun Hyoung Lee ◽  
Ju Young Lee ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Transformation Efficiency ◽  
Coli Strain ◽  
Type I ◽  
Wild Type ◽  
Planktonic Cells ◽  
Acid Biosynthesis ◽  
E Coli ◽  
Biofilm Production ◽  
Abiotic Surfaces

ABSTRACT Bacteria form biofilms by adhering to biotic or abiotic surfaces. This phenomenon causes several problems, including a reduction in the transport of mass and heat, an increase in resistance to antibiotics, and a shortening of the lifetimes of modules in bioindustrial fermentors. To overcome these difficulties, we created a biofilm production-deficient Escherichia coli strain, BD123, by deleting genes involved in curli biosynthesis and assembly, Δ(csgG-csgC); colanic acid biosynthesis and assembly, Δ(wcaL-wza); and type I pilus biosynthesis, Δ(fimB-fimH). E. coli BD123 remained mostly in the form of planktonic cells under the conditions tested and became more sensitive to the antibiotics streptomycin and rifampin than the wild-type E. coli MG1655: the growth of BD123 was inhibited by one-fourth of the concentrations needed to inhibit MG1655. In addition, the transformation efficiency of BD123 was about 20 times higher than that of MG1655, and the production and secretion of recombinant proteins were ∼16% and ∼25% greater, respectively, with BD123 than with MG1655. These results indicate that the newly created biofilm production-deficient strain of E. coli displays several key properties that substantially enhance its utility in the biotechnology arena.

scholarly journals Transposon Insertion in the purL Gene Induces Biofilm Depletion in Escherichia coli ATCC 25922

Pathogens ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 774
Author(s):  
Virginio Cepas ◽  
Victoria Ballén ◽  
Yaiza Gabasa ◽  
Miriam Ramírez ◽  
Yuly López ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
De Novo ◽  
Wild Type ◽  
Planktonic Cells ◽  
E Coli ◽  
Qrt Pcr ◽  
Transposon Insertion ◽  
De Novo Purine Biosynthesis

Current Escherichia coli antibiofilm treatments comprise a combination of antibiotics commonly used against planktonic cells, leading to treatment failure. A better understanding of the genes involved in biofilm formation could facilitate the development of efficient and specific new antibiofilm treatments. A total of 2578 E. coli mutants were generated by transposon insertion, of which 536 were analysed in this study. After sequencing, Tn263 mutant, classified as low biofilm-former (LF) compared to the wild-type (wt) strain (ATCC 25922), showed an interruption in the purL gene, involved in the de novo purine biosynthesis pathway. To elucidate the role of purL in biofilm formation, a knockout was generated showing reduced production of curli fibres, leading to an impaired biofilm formation. These conditions were restored by complementation of the strain or addition of exogenous inosine. Proteomic and transcriptional analyses were performed to characterise the differences caused by purL alterations. Thirteen proteins were altered compared to wt. The corresponding genes were analysed by qRT-PCR not only in the Tn263 and wt, but also in clinical strains with different biofilm activity. Overall, this study suggests that purL is essential for biofilm formation in E. coli and can be considered as a potential antibiofilm target.

scholarly journals Selection for non-specific adhesion is a driver of FimH evolution increasing Escherichia coli biofilm capacity

2021 ◽  
Author(s):  
Mari YOSHIDA ◽  
Stanislas THIRIET-RUPERT ◽  
Leonie MAYER ◽  
Christophe BELOIN ◽  
Jean-Marc GHIGO
Keyword(s):  
Escherichia Coli ◽  
Selective Advantage ◽  
Coli Strain ◽  
Adhesion Properties ◽  
Lectin Domain ◽  
E Coli ◽  
Type 1 Fimbriae ◽  
Abiotic Surfaces ◽  
Selection For

Bacterial interactions with surfaces rely on the coordinated expression and interplay of surface exposed adhesion factors. However, how bacteria dynamically modulate their vast repertoire of adhesins to achieve surface colonization is not yet well-understood. We used experimental evolution and positive selection for improved adhesion to investigate how an initially poorly adherent Escherichia coli strain increased its adhesion capacities to abiotic surfaces. We showed that all identified evolved clones acquired mutations located almost exclusively in the lectin domain of fimH, the gene coding for the alpha-D-mannose-specific tip adhesin of type 1 fimbriae. While most of these fimH mutants showed reduced mannose-binding ability, they all displayed enhanced binding to abiotic surfaces, indicating a trade-off between FimH-mediated specific and non-specific adhesion properties. Several of the identified mutations were already reported in FimH lectin domain of pathogenic and environmental E. coli, suggesting that, beyond patho-adaptation, FimH microevolution favoring non-specific surface adhesion could constitute a selective advantage for natural E. coli isolates. Consistently, although E. coli deleted for the fim operon still evolves an increased adhesion capacity, mutants selected in the ∆fim background are outcompeted by fimH mutants revealing clonal interference for adhesion. Our study therefore provides insights into the plasticity of E. coli adhesion potential and shows that evolution of type 1 fimbriae is a major driver of the adaptation of natural E. coli to colonization.

scholarly journals Biofilm Formation by Escherichia coli O157:H7 on Stainless Steel: Effect of Exopolysaccharide and Curli Production on Its Resistance to Chlorine

2005 ◽  
Vol 71 (1) ◽  
pp. 247-254 ◽  
Author(s):  
Jee-Hoon Ryu ◽  
Larry R. Beuchat
Keyword(s):  
Escherichia Coli ◽  
Stainless Steel ◽  
Biofilm Formation ◽  
Escherichia Coli O157 ◽  
Strain Atcc ◽  
Planktonic Cells ◽  
E Coli ◽  
Biofilm Production ◽  
Resistant Population ◽  
Population Sizes

ABSTRACT The resistance of Escherichia coli O157:H7 strains ATCC 43895-, 43895-EPS (an exopolysaccharide [EPS]-overproducing mutant), and ATCC 43895+ (a curli-producing mutant) to chlorine, a sanitizer commonly used in the food industry, was studied. Planktonic cells of strains 43895-EPS and/or ATCC 43895+ grown under conditions supporting EPS and curli production, respectively, showed the highest resistance to chlorine, indicating that EPS and curli afford protection. Planktonic cells (ca. 9 log10 CFU/ml) of all strains, however, were killed within 10 min by treatment with 50 μg of chlorine/ml. Significantly lower numbers of strain 43895-EPS, compared to those of strain ATCC 43895-, attached to stainless steel coupons, but the growth rate of strain 43895-EPS on coupons was not significantly different from that of strain ATCC 43895-, indicating that EPS production did not affect cell growth during biofilm formation. Curli production did not affect the initial attachment of cells to coupons but did enhance biofilm production. The resistance of E. coli O157:H7 to chlorine increased significantly as cells formed biofilm on coupons; strain ATCC 43895+ was the most resistant. Population sizes of strains ATCC 43895+ and ATCC 43895- in biofilm formed at 12�C were not significantly different, but cells of strain ATCC 43895+ showed significantly higher resistance than did cells of strain ATCC 43895-. These observations support the hypothesis that the production of EPS and curli increase the resistance of E. coli O157:H7 to chlorine.

scholarly journals Complete Genome Sequence of the Wild-Type Commensal Escherichia coli Strain SE15, Belonging to Phylogenetic Group B2

2009 ◽  
Vol 192 (4) ◽  
pp. 1165-1166 ◽  
Author(s):  
Hidehiro Toh ◽  
Kenshiro Oshima ◽  
Atsushi Toyoda ◽  
Yoshitoshi Ogura ◽  
Tadasuke Ooka ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Genome Sequence ◽  
Complete Genome Sequence ◽  
Complete Genome ◽  
Healthy Adult ◽  
Coli Strain ◽  
Phylogenetic Group ◽  
Wild Type ◽  
Commensal Bacterium ◽  
E Coli

ABSTRACT Escherichia coli SE15 (O150:H5) is a human commensal bacterium recently isolated from feces of a healthy adult and classified into E. coli phylogenetic group B2, which includes the majority of extraintestinal pathogenic E. coli. Here, we report the finished and annotated genome sequence of this organism.

Isolation and characterization of catabolite repression-resistant mutants of Escherichia coli

1977 ◽  
Vol 23 (10) ◽  
pp. 1384-1393 ◽  
Author(s):  
Glen D. Armstrong ◽  
Hiroshi Yamazaki
Keyword(s):  
Escherichia Coli ◽  
Catabolite Repression ◽  
Coli Strain ◽  
Wild Type ◽  
Phosphotransferase System ◽  
E Coli ◽  
Isolation And Characterization ◽  
In The Wild ◽  
Resistant Mutants

A method has been developed for the isolation of Escherichia coli mutants which are resistant to catabolite repression. The method is based on the fact that a mixture of glucose and gluconate inhibits the development of chemotactic motility in the wild type, but not in the mutants. A motile E. coli strain was mutagenized and grown in glucose and gluconate. Mutants which were able to swim into a tube containing a chemotactic attractant (aspartic acid) were isolated. Most of these mutants were able to produce β-galactosidase in the presence of glucose and gluconate and were normal in their ability to degrade adenosine 3′,5′-cyclic monophosphate. Some of these mutants were defective in the glucose phosphotransferase system.

scholarly journals The Escherichia coli Efflux Pump TolC Promotes Aggregation of Enteroaggregative E. coli 042

2007 ◽  
Vol 76 (3) ◽  
pp. 1247-1256 ◽  
Author(s):  
Naoko Imuta ◽  
Junichiro Nishi ◽  
Koichi Tokuda ◽  
Rika Fujiyama ◽  
Kunihiro Manago ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Outer Membrane ◽  
Efflux Pump ◽  
Microtiter Plate ◽  
Virulence Plasmid ◽  
Wild Type ◽  
Planktonic Cells ◽  
Microtiter Plate Assay ◽  
E Coli ◽  
Aggregative Adherence

ABSTRACT Enteroaggregative Escherichia coli (EAEC) is an emerging enteric pathogen in both developing and industrialized countries. EAEC is defined as a diarrheal pathogen based on its characteristic aggregative adherence to HEp-2 cells in culture and its biofilm formation on the intestinal mucosa. We have reported that the novel protein AatA, which is encoded on the EAEC virulence plasmid pAA2, localizes to the outer membrane and facilitates export of the dispersin Aap across the outer membrane. Because AatA is an E. coli efflux pump TolC homolog, we investigated the role of TolC in the virulence of EAEC. No difference in Aap secretion was observed between the wild type and its tolC mutant (042tolC). However, characteristic aggregation in high-glucose Dulbecco's minimal essential medium for the wild type was diminished for 042tolC. In a microtiter plate assay, there were significantly more planktonic cells for 042tolC than for the wild type, while there were significantly fewer spontaneously precipitated cells on the substratum for 042tolC than for the wild type. In a HEp-2 cell adherence test, 042tolC showed less aggregative adherence than did the wild type. The strong aggregation and aggregative adherence were restored in the complement strain with tolC. In a transwell assay, planktonic cells of 042tolC decreased when cocultured with the wild type or the complement, while precipitated cells of 042tolC increased when cocultured with them. These results suggest that TolC promotes the aggregation and adhesion of EAEC 042 by secreting an assumed humoral factor.

Isolation of an Escherichia coli strain mutant unable to form biofilm on polystyrene and to adhere to human pneumocyte cells: involvement of tryptophanase

2002 ◽  
Vol 48 (2) ◽  
pp. 132-137 ◽  
Author(s):  
P Di Martino ◽  
A Merieau ◽  
R Phillips ◽  
N Orange ◽  
C Hulen
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
A549 Cells ◽  
Coli Strain ◽  
Gene Encoding ◽  
Cell Monolayers ◽  
E Coli ◽  
Transposon Insertion ◽  
Abiotic Surfaces ◽  
Tryptophanase Activity

Escherichia coli adherence to biotic and abiotic surfaces constitutes the first step of infection by promoting colonization and biofilm formation. The aim of this study was to gain a better understanding of the relationship between E. coli adherence to different biotic surfaces and biofilm formation on abiotic surfaces. We isolated mutants defective in A549 pneumocyte cells adherence, fibronectin adherence, and biofilm formation by random transposition mutagenesis and sequential passages over A549 cell monolayers. Among the 97 mutants tested, 80 were decreased in biofilm formation, 8 were decreased in A549 cells adherence, 7 were decreased in their adherence to fibronectin, and 17 had no perturbations in either of the three phenotypes. We observed a correlation between adherence to fibronectin or A549 cells and biofilm formation, indicating that biotic adhesive factors are involved in biofilm formation by E. coli. Molecular analysis of the mutants revealed that a transposon insertion in the tnaA gene encoding for tryptophanase was associated with a decrease in both A549 cells adherence and biofilm formation by E. coli. The complementation of the tnaA mutant with plasmid-located wild-type tnaA restored the tryptophanase activity, epithelial cells adherence, and biofilm formation on polystyrene. The possible mechanism of tryptophanase involvement in E. coli adherence and biofilm formation is discussed.Key words: Escherichia coli, biofilm, adherence, A549 cells, fibronectin, tryptophanase.

scholarly journals LT-IIc, a New Member of the Type II Heat-Labile Enterotoxin Family Encoded by an Escherichia coli Strain Obtained from a Nonmammalian Host

2010 ◽  
Vol 78 (11) ◽  
pp. 4705-4713 ◽  
Author(s):  
Hesham F. Nawar ◽  
Natalie D. King-Lyons ◽  
John C. Hu ◽  
Raymond C. Pasek ◽  
Terry D. Connell
Keyword(s):  
Escherichia Coli ◽  
Coli Strain ◽  
Amino Acid Sequences ◽  
Type I ◽  
Avian Host ◽  
Type Ii ◽  
E Coli ◽  
Heat Labile ◽  
Genes Encoding ◽  
New Type

ABSTRACT Two families of bacterial heat-labile enterotoxins (HLTs) have been described: the type I HLTs are comprised of cholera toxin (CT) of Vibrio cholerae, LT-I of Escherichia coli, and several related HLTs; the type II HLTs are comprised of LT-IIa and LT-IIb. Herein, we report LT-IIc, a new type II HLT encoded from an enterotoxigenic E. coli (ETEC) strain isolated from an avian host. Using a mouse Y1 adrenal cell bioassay, LT-IIc was shown to be less cytotoxic than CT, LT-IIa, or LT-IIb. Cytotoxicity of LT-IIc was partially neutralized by antisera recognizing LT-IIa or LT-IIb but not by anti-CT antiserum. Genes encoding putative A polypeptide and B polypeptides of LT-IIc were arranged in an operon which was flanked by potential prophage sequences. Analysis of the nucleotide and predicted amino acid sequences demonstrated that the A polypeptide of LT-IIc has moderate homology to the A polypeptides of CT and LT-I and high homology to the A polypeptides of LT-IIa and LT-IIb. The B polypeptide of LT-IIc exhibited no significant homology to the B polypeptides of CT and LT-I and only moderate homology to the B polypeptides of LT-IIa and LT-IIb. The binding pattern of LT-IIc for gangliosides was distinctive from that of either LT-IIa or LT-IIb. The data suggest that other types of the type II HLT subfamily are circulating in the environment and that host specificity of type II HLT is likely governed by changes in the B polypeptide which mediate binding to receptors.

Effects of the twin-arginine translocase on the structure and antimicrobial susceptibility of Escherichia coli biofilms

2005 ◽  
Vol 51 (8) ◽  
pp. 671-683 ◽  
Author(s):  
Joe J Harrison ◽  
Howard Ceri ◽  
Erin A Badry ◽  
Nicole J Roper ◽  
Kerry L Tomlin ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
Type Strain ◽  
Wild Type Strain ◽  
Wild Type ◽  
Planktonic Cells ◽  
E Coli ◽  
Minimal Media ◽  
Twin Arginine Translocase ◽  
Biofilm Structure

In this descriptive study, we used Escherichia coli twin-arginine translocase (tat) mutants to distinguish antibiotic tolerance from the formation of mature biofilm structure. Biofilm formation by wild-type and Δtat strains of E. coli was evaluated using viable cell counts, scanning electron microscopy, and confocal laser-scanning microscopy. Escherichia coli Δtat mutants had an impaired ability to form biofilms when grown in rich or minimal media. These mutants produced disorganized layers and cell aggregates with significantly decreased cell density relative to the wild-type strain. In contrast, wild-type E. coli grown under similar test conditions formed highly structured, surface-adherent communities. We thus determined if this decreased biofilm formation by E. coli Δtat mutants may result in lowered tolerance to antimicrobials. When grown in rich media, planktonic Δtat mutants were hypersensitive to some metals, detergents, and antibiotics. However, the corresponding biofilms were about as resilient as the wild-type strain. In contrast, both planktonic cells and biofilms of the ΔtatABC strain grown in minimal media were hypersensitive to many antimicrobials. Remarkably, these biofilms remained up to 365 times more tolerant to β-lactams than corresponding planktonic cells. Our data suggest that the twin-arginine translocase may play a contributing role in the antimicrobial tolerance, structural organization, and formation of mature E. coli biofilms under nutrient-limited conditions. However, the high tolerance of the ΔtatABC strain to bactericidal concentrations of antimicrobials indicates that mature biofilm structure may not be required for surface-adherent E. coli to survive exposure to these lethal factors.Key words: biofilm structure, twin-arginine translocase (tat), Escherichia coli, antimicrobial susceptibility/tolerance.

scholarly journals The composition of an unusual precursor of 50 S ribosomes in a mutant of Escherichia coli

1976 ◽  
Vol 158 (2) ◽  
pp. 451-456 ◽  
Author(s):  
F Markey ◽  
P F Sims ◽  
D G Wild
Keyword(s):  
Escherichia Coli ◽  
Exponential Growth ◽  
Coli Strain ◽  
Wild Type ◽  
E Coli ◽  
Type Strains

Escherichia coli strain 15–28 is a mutant which during exponential growth contains large amounts of a ‘47S’ ribonucleoprotein precursor to 50S ribosomes. The ‘47S particles’ are more sensitive to ribonuclease than are 50S ribosomes. The 23 S RNA of 47S particles may be slightly undermethylated, but cannot be distinguished from the 23S RNA of 50S ribosomes by sedimentation or electrophoresis. Isolated particles have 10–15% less protein than do 50S ribosomes; proteins L16, L28 and L33 are absent. Comparison with precursor particles studied by other workers in wild-type strains of E. coli suggests that the assembly of 50S ribosomes in strain 15–28 is atypical.

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