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1

Multiplexed amino acid array utilizing bioluminescent Escherichia coli auxotrophs.  

PubMed

We describe a novel multiplex "amino acid array" for simultaneously quantifying different amino acids based on the rapid growth of amino acid auxotrophic E. coli. First, we constructed genetically engineered amino acid auxotrophs of E. coli containing a bioluminescence reporter gene, yielding concomitant luminescence as a response to cell growth, and then immobilized the reporter cells within individual agarose of respective wells in a 96-well plate serving as a mimic of a biochip. Using the amino acid array, we were able to determine quantitatively the concentrations of 16 amino acids in biological fluid by simply measuring bioluminescent signals from the immobilized cells within 4 h without pre- and post-treatment. The clinical utility of this method was verified by quantifying different amino acids in dried blood spot specimens from clinical samples for the diagnosis of metabolic diseases of newborn babies. This method serves as a convenient route to the rapid and simultaneous analysis of multiple amino acids from complex biological fluids and represents a new analytical paradigm that can replace conventional, yet laborious methods currently in use. PMID:20405822

Kim, Moon Il; Yu, Byung Jo; Woo, Min-Ah; Cho, Daeyeon; Dordick, Jonathan S; Cho, June Hyoung; Choi, Byung-Ok; Park, Hyun Gyu

2010-05-15

2

In Vivo Imaging of Bioluminescent Escherichia coli in a Cutaneous Wound Infection Model for Evaluation of an Antibiotic Therapy  

Microsoft Academic Search

A rapid, continuous method for noninvasively monitoring the effectiveness of several antibacterial agents in real time by using a model of wound infection was developed. This study was divided into three steps: (i) construction of a plasmid to transform Escherichia coli into a bioluminescent variant, (ii) study of the bioluminescent E. coli in vitro as a function of temperature and

Samir Jawhara; Serge Mordon

2004-01-01

3

Bacteriophage-amplified bioluminescent sensing of Escherichia coli O157:H7.  

PubMed

Escherichia coli O157:H7 remains a continuous public health threat, appearing in meats, water, fruit juices, milk, cheese, and vegetables, where its ingestion at concentrations of perhaps as low as 10 to 100 organisms can result in potent toxin exposure and severe damage to the lining of the intestine. Abdominal pain and diarrhea develop, which in the very young or elderly can progress towards hemolytic uremic syndrome and kidney failure. To assist in the detection of E. coli O157:H7, a recombinant bacteriophage reporter was developed that uses quorum sensing (luxI/luxR) signaling and luxCDABE-based bioluminescent bioreporter sensing to specifically and autonomously respond to O157:H7 serotype E. coli. The bacteriophage reporter, derived from phage PP01, was tested in artificially contaminated foodstuffs including apple juice, tap water, ground beef, and spinach leaf rinsates. In apple juice, detection of E. coli O157:H7 at original inoculums of 1 CFU mL(-1) occurred within approximately 16 h after a 6-h pre-incubation, detection of 1 CFU mL(-1) in tap water occurred within approximately 6.5 h after a 6-h pre-incubation, and detection in spinach leaf rinsates using a real-time Xenogen IVIS imaging system resulted in detection of 1 CFU mL(-1) within approximately 4 h after a 2-h pre-incubation. Detection in ground beef was not successful, however, presumably due to the natural occurrence of quorum sensing autoinducer (N-3-(oxohexanoyl)-L: -homoserine lactone; OHHL), which generated false-positive bioreporter signals in the ground beef samples. PMID:18188543

Ripp, Steven; Jegier, Patricia; Johnson, Courtney M; Brigati, Jennifer R; Sayler, Gary S

2008-05-01

4

Immobilization of bioluminescent Escherichia coli cells using natural and artificial fibers treated with polyethyleneimine.  

PubMed

Biosensors based on whole-cell bioluminescence have the potential to become a cost-effective alternative to conventional detection methods upon validation of target selectivity and sensitivity. However, quantitative analysis of bioluminescence is greatly hindered due to lack of control over the total number of cells in a suspending culture. In this study, the effect of surface properties of genetically engineered luminous E. coli cells and fibrous matrices on the immobilization capacity and effectiveness under various environmental conditions were characterized. Four different fibers, including cotton, polyester, viscose rayon, and silk, were investigated. Although cell adhesion was observed on untreated viscose and cotton fibers, viscose fiber pretreated with 0.667% polyethyleneimine (PEI) was found capable of immobilizing the most viable E. coli DPD2234 cells, followed by viscose treated with 0.33% and 1% PEI. The cells immobilized on PEI-treated viscose remained viable and yielded 20% or more bioluminescence signals immediately upon contact with the inducer up to 72 h without feeding nutrients to the cells, suggesting that viscose treated with 0.667% PEI could provide a stable immobilization mechanism for bioluminescent E. coli cells with long sensing period, quick response time, and good signal reproducibility. PMID:19285859

Chu, Yi-Fang; Hsu, Chia-Hua; Soma, Pavan K; Lo, Y Martin

2009-07-01

5

LuxCDABE—Transformed Constitutively Bioluminescent Escherichia coli for Toxicity Screening: Comparison with Naturally Luminous Vibrio fischeri  

PubMed Central

We show that in vitro toxicity assay based on inhibition of the bioluminescence of recombinant Escherichia coli encoding thermostable luciferase from Photorhabdus luminescens is a versatile alternative to Vibrio fischeri Microtox™ test. Performance of two luxCDABE-transformed E. coli MC1061 constructs (pDNlux) and (pSLlux) otherwise identical, but having 100-fold different background luminescence was compared with the performance of V. fischeri. The microplate luminometer and a kinetic Flash-Assay test format was used that differently from Microtox test is also applicable for high throughput analysis. Toxic effects (30-s till 30-min EC50) of four heavy metals (Zn, Cd, Hg, Cu) and three organic chemicals (aniline, 3,5-dichloroaniline and 3,5-dichlorophenol) were studied. Both E. coli strains had comparable sensitivity and the respective 30-min EC50 values highly correlated (log-log R2 = 0.99; p < 0.01) showing that the sensitivity of the recombinant bacteria towards chemicals analyzed did not depend on the bioluminescence level of the recombinant cells. The most toxic chemical for all used bacterial strains (E. coli, V. fischeri) was mercury whereas the lowest EC50 values for Hg (0.04–0.05 mg/L) and highest EC50 values for aniline (1,300–1,700 mg/L) were observed for E. coli strains. Despite of that, toxicity results obtained with both E. coli strains (pSLlux and pDNlux) significantly correlated with V. fischeri results (log-log R2 = 0.70/0.75; p < 0.05/0.01). The use of amino acids (0.25%) and glucose (0.05%)-supplemented M9 medium instead of leucine-supplemented saline significantly (p < 0.05) reduced the apparent toxicity of heavy metals to both E. coli strains up to three orders of magnitude, but had little or no complexing effect on organic compounds. Thus, P. luminescens luxCDABE-transformed E. coli strains can be successfully used for the acute toxicity screening of various types of organic chemicals and heavy metals and can replace V. fischeri in certain cases where the thermostability of luciferase >30 °C is crucial. The kinetic Flash Assay test format of the bioluminescence inhibition assay facilitates high throughput analysis. The assay medium, especially in case of testing heavy metals should be a compromise: optimal for the viability/luminescence of the recombinant test strain and of minimum complexing potential. PMID:22164050

Kurvet, Imbi; Ivask, Angela; Bondarenko, Olesja; Sihtmäe, Mariliis; Kahru, Anne

2011-01-01

6

Bacteriophage-amplified bioluminescent sensing of Escherichia coli O157:H7  

Microsoft Academic Search

Escherichia coli O157:H7 remains a continuous public health threat, appearing in meats, water, fruit juices, milk, cheese, and vegetables,\\u000a where its ingestion at concentrations of perhaps as low as 10 to 100 organisms can result in potent toxin exposure and severe\\u000a damage to the lining of the intestine. Abdominal pain and diarrhea develop, which in the very young or elderly

Steven Ripp; Patricia Jegier; Courtney M. Johnson; Jennifer R. Brigati; Gary S. Sayler

2008-01-01

7

Use of bioluminescent Escherichia coli to determine retention during the life cycle of the housefly, Musca domestica (Diptera: Muscidae, L).  

PubMed

Researchers have documented that the housefly (Musca domestica) can serve as a vector for the spread of foodborne pathogens to livestock, food, and humans. Most studies have investigated Musca domestica as a vector only after the fly comes into contact or consumes the pathogen as an adult. The objective of this study was to determine whether the larvae of Musca domestica could ingest Escherichia coli from bovine manure and whether the E. coli could survive the metamorphosis process and be transmitted. Larvae (n=960) were incubated in sterilized bovine manure inoculated with 0, 3, 5, and 8 log10 colony-forming units (CFU)/mL of bioluminescent E. coli for 24 (larvae stage), 48 (larvae stage), 120 (pupae stage), and 192?h (adult stage). Larvae incubated for 24?h in bovine manure possessed 0.0, 2.7, 2.9, and 3.5 log(10) CFU/mL of E. coli, from inoculated with 0, 3, 5, and 8 log(10) CFU/mL of E. coli, respectively. Concentrations of E. coli within the pupae were 0.0, 1.7, 1.9, and 2.2 log(10) CFU/mL for each inoculation concentration, respectively. Flies that emerged from the pupae stage contained 0.0, 1.3, 2.2, and 1.7 log(10) CFU/mL of E. coli from larvae incubated in manure inoculated with concentrations of E. coli, respectively. These results suggest the housefly can emerge with quantities of E. coli. While this was an enteropathogenic E. coli (EPEC), these data may suggest that if the fly is capable of retaining similar concentrations of an enterohemorrhagic E. coli (EHEC), these concentrations may be capable of initiating illness in humans. Furthermore, the E. coli concentration within and on adult flies is related to environmental exposure. It must be noted that larvae were incubated in sterilized bovine manure, and there was no other bacterial competition for the E. coli. Thus, the rate of positive flies and concentrations present when flies emerged may vary under more realistic conditions. PMID:23536983

Schuster, Greta L; Donaldson, Janet R; Buntyn, Joe O; Duoss, Heather A; Callaway, Todd R; Carroll, Jeff A; Falkenberg, Shollie M; Schmidt, Ty B

2013-05-01

8

Validation of a Noninvasive, Real-Time Imaging Technology Using Bioluminescent Escherichia coli in the Neutropenic Mouse Thigh Model of Infection  

Microsoft Academic Search

A noninvasive, real-time detection technology was validated for qualitative and quantitative antimicrobial treatment applications. The lux gene cluster of Photorhabdus luminescens was introduced into an Escherichia coli clinical isolate, EC14, on a multicopy plasmid. This bioluminescent reporter bacterium was used to study antimicrobial effects in vitro and in vivo, using the neutropenic-mouse thigh model of infection. Biolumines- cence was monitored

H. L. Rocchetta; C. J. Boylan; J. W. Foley; P. W. Iversen; D. L. LeTourneau; C. L. McMillian; P. R. Contag; D. E. Jenkins; T. R. Parr

2001-01-01

9

Escherichia coli (E. coli)  

MedlinePLUS

... so you might hear about E. coli being found in drinking water, which are not themselves harmful, but indicate the ... Infections start when you swallow STEC—in other words, when you get tiny ... consumption of water that has not been disinfected, contact with cattle, ...

10

Escherichia coli biofilms  

PubMed Central

Escherichia coli is a predominant species among facultative anaerobic bacteria of the gastrointestinal tract. Both its frequent community lifestyle and the availability of a wide array of genetic tools contributed to establish E. coli as a relevant model organism for the study of surface colonization. Several key factors, including different extracellular appendages, are implicated in E. coli surface colonization and their expression and activity are finely regulated, both in space and time, to ensure productive events leading to mature biofilm formation. This chapter will present known molecular mechanisms underlying biofilm development in both commensal and pathogenic E. coli. PMID:18453280

Beloin, Christophe; Roux, Agnes; Ghigo, Jean-Marc

2008-01-01

11

Article de synthse Escherichia coli  

E-print Network

Article de synthèse Escherichia coli entéropathogènes du lapin D Licois INRA, Station de pathologie diarrhée, chez l'homme ou l'animal. Escherichia coli/ entéropathogène / entérohémorragique / lapin Summary ― Enteropathogenic Escherichia coli from the rabbit. Intestinal pathology is the main cause

Paris-Sud XI, Université de

12

Escherichia coli diarrhoea*  

PubMed Central

In recent years it has become clear that three types of Escherichia coli—enterotoxigenic, enteropathogenic, and enteroinvasive—play important roles in the etiology of acute diarrhoea. This report reviews the available knowledge on the epidemiology, clinical features, and pathophysiology of acute diarrhoea caused by these three types of E. coli, summarizes information on their laboratory diagnosis, and outlines priorities for further research. Particular attention is paid to important aspects of the relationship between enterotoxigenic E. coli diarrhoea in young animals and in man, and to recent advances in the development of E. coli vaccines for use in animals and their potential relevance to the development of an E. coli vaccine for use in man. PMID:6991145

1980-01-01

13

Review article Avian pathogenic Escherichia coli (APEC)  

E-print Network

Review article Avian pathogenic Escherichia coli (APEC) Maryvonne Dho-Moulina John Morris Inra/Elscvier, Paris. avian / Escherichia coli / virulence / fimbriae / capsule / aerobactin.int-a. li- #12;Résumé-Escherichia coli pathogènes aviaires (APEC). Les Escherichia coli pathogènes aviaires

Paris-Sud XI, Université de

14

GroEL\\/GroES chaperone and Lon protease regulate expression of the Vibrio fischeri lux operon in Escherichia coli  

Microsoft Academic Search

Chaperone GroEL\\/GroES and Lon protease were shown to play a role in regulating the expression of the Vibrio fischeri lux operon cloned in Escherichia coli cells. The E. coli groE mutant carrying a plasmid with the full-length V. fischeri lux regulon showed a decreased bioluminescence. The bioluminescence intensity was high in E. coli cells with mutant lonA and the same

I. V. Manukhov; V. Yu. Kotova; G. B. Zavilgelsky

2006-01-01

15

Bioluminescence  

NSDL National Science Digital Library

This Bioluminescence webpage is an entry in Kimball's online biology textbook. It discusses the ability of living things to emit light, the various molecules involved, how fireflies control their flashing, and bioluminescence in marine organisms.

Kimball, John W.; Pages, Kimball'S B.

16

Escherichia coli proteomics and bioinformatics  

E-print Network

A lot of things happen to proteins when Escherichia coli cells enter stationary phase, such as protein amount, post-translational modifications, conformation changes, and component of protein complex. Proteomics, which study the whole component...

Niu, Lili

2009-05-15

17

ORIGINAL ARTICLE Competitive interactions in Escherichia coli  

E-print Network

ORIGINAL ARTICLE Competitive interactions in Escherichia coli populations: the role of bacteriocins Escherichia coli strains were generated, each carrying a DNA-degrading bacteriocin (colicins E2 and E7). Using exclusion; Escherichia coli; bacteriocin; structured environment Introduction Without question, bacteriocins

Riley, Margaret

18

Review article Pathogenic diversity of Escherichia coli  

E-print Network

Review article Pathogenic diversity of Escherichia coli and the emergence of 'exotic' islands December 1998) Abstract - Escherichia coli is a highly adaptive bacterial species that is both a member and other bacteria are presented. © Inra/Elsevier, Paris. Escherichia coli / pathogenicity island

Boyer, Edmond

19

Review article Enterotoxigenic Escherichia coli (ETEC)  

E-print Network

Review article Enterotoxigenic Escherichia coli (ETEC) in farm animals Béla Nagy* Péter Zs. Fekete to enterotoxigenic Escherichia coli (ETEC) typically appear as severe watery diarrhoea during the first few daysC novell.vnu-i.hu Résumé - Escherichia coli entérotoxigène (ETEC) chez les animaux de la ferme. L

Paris-Sud XI, Université de

20

Bioluminescence.  

ERIC Educational Resources Information Center

Describes bioluminescence and the chemistry of how it occurs. Presents information for conducting the following classroom activities: (1) firefly mimic; (2) modeling deep-sea fish; (3) sea fireflies; and (4) the chemistry of light. (PR)

Jones, M. Gail

1993-01-01

21

High level indole signalling in Escherichia coli  

E-print Network

1 High level indole signalling in Escherichia coli Hannah Dorne Gaimster Girton College Department of Genetics A dissertation submitted for the degree of Doctor of Philosophy: April 2014 2 Title High level... indole signalling in Escherichia coli Abstract Indole is a small signalling molecule, produced by many species of bacteria, including Escherichia coli. It is made by the enzyme tryptophanase, which converts tryptophan into indole, pyruvate and ammonia...

Gaimster, Hannah Dorne

2014-06-10

22

Ertapenem Resistance of Escherichia coli  

E-print Network

An ertapenem-resistant Escherichia coli isolate was recovered from peritoneal fluid in a patient who had been treated with imipenem/cilastatin for 10 days. Ertapenem resistance may be explained by a defect in the outer membrane protein and production of extended-spectrum ?-lactamase CTX-M-2. Of all ?-lactam antimicrobial drugs, carbapenems (imipenem, meropenem, and ertapenem) have the most consistent activity against Enterobacteriaceae. Activity is retained against most isolates that produce high-level AmpC ?-lactamases (cephalosporinases) and clavulanic-acid–inhibited extended-spectrum ?-lactamases (ESBL) (1). However, a few carbapenem-resistant enterobacterial isolates have been reported; resistance may be caused by production of carbapenemases (2) or by combined mechanisms of an outer membrane permeability defect and extended-spectrum ?-lactamases or cephalosporinase (3–6). Spread of CTX-M type ESBLs, especially in Escherichia coli, may provide a favorable background for selection of carbapenem resistance. Resistance to the recently introduced ertapenem has not been reported in E. coli associated with a CTX-M-type enzyme. We describe the clinical and microbiologic features associated with an ertapenem-resistant E. coli isolate that had reduced susceptibility to imipenem after in vivo treatment with imipenem/cilastatin and provide a detailed molecular analysis of the antimicrobial drug resistance mechanisms. The Study E. coli CO strain was recovered from a 50-year-old immunocompromised woman who was hospitalized for a combined liver and heart transplant. She had a history of cardiac failure, hepatitis C virus–related liver cirrhosis, and chronic renal insufficiency. After surgery, septic shock developed related to perforation of the colon. The patient received a full dose of imipenem/cilastatin (2 g/day), a reduced dose of vancomycin (400 mg/day), gentamicin

Marie-frédérique Lartigue; Laurent Poirel; Claire Poyart; Hélène Réglier-poupet; Patrice Nordmann

23

The Escherichia coli Peripheral Inner Membrane Proteome*S  

E-print Network

The Escherichia coli Peripheral Inner Membrane Proteome*S Malvina Papanastasiou, Georgia Escherichia coli using a multidisciplinary approach. Initially, we extensively re-an- notated the theoretical- romolecular complexes, and modification and degradation of poplypeptides. Escherichia coli, a model organism

Economou, Tassos

24

GENOMICS AND PROTEOMICS Temporal regulation of enterohemorrhagic Escherichia coli  

E-print Network

GENOMICS AND PROTEOMICS Temporal regulation of enterohemorrhagic Escherichia coli virulence Escherichia coli (EHEC) infections. AI-2 attracted EHEC in agarose plug chemotaxis assays and also increased). However, the introduction of pathogens, such as enterohemorrhagic Escherichia coli (EHEC), into the GI

Wood, Thomas K.

25

21 CFR 866.3255 - Escherichia coli serological reagents.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Escherichia coli serological reagents. 866...Serological Reagents § 866.3255 Escherichia coli serological reagents. (a) Identification. Escherichia coli serological reagents...

2011-04-01

26

ORIGINAL RESEARCH Shigella Strains Are Not Clones of Escherichia coli  

E-print Network

ORIGINAL RESEARCH Shigella Strains Are Not Clones of Escherichia coli but Sister Species Available online 29 December 2012 KEYWORDS Shigella; Escherichia coli; Prokaryote phylogeny and taxonomy; Composition vector; CVTree Abstract Shigella species and Escherichia coli are closely related organisms. Early

Hao, Bailin

27

21 CFR 866.3255 - Escherichia coli serological reagents.  

...2014-04-01 2014-04-01 false Escherichia coli serological reagents. 866...Serological Reagents § 866.3255 Escherichia coli serological reagents. (a) Identification. Escherichia coli serological reagents...

2014-04-01

28

21 CFR 866.3255 - Escherichia coli serological reagents.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Escherichia coli serological reagents. 866...Serological Reagents § 866.3255 Escherichia coli serological reagents. (a) Identification. Escherichia coli serological reagents...

2012-04-01

29

21 CFR 866.3255 - Escherichia coli serological reagents.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Escherichia coli serological reagents. 866...Serological Reagents § 866.3255 Escherichia coli serological reagents. (a) Identification. Escherichia coli serological reagents...

2013-04-01

30

Interaction of Escherichia coli O55 hybrids with bacteriophage lambda. A new type of host specificity between Escherichia coli O55 and urinary Escherichia coli  

Microsoft Academic Search

Escherichia coli O55 hybrids able to adsorb the lambda phage were obtained by mating anEscherichia coli O55 recipient with anEscherichia coli K12HfrC donor. ? mutants, capable of forming plaques on these hybrids, were not isolated. A new type of host specificity betweenEscherichia coli O55 and urinaryEscherichia coli J was established. For efficient reduction of the phage plating ability more growth

K. ?ejka; J. Hubá?ek

1974-01-01

31

SEROLOGICAL CROSS-REACTIONS BETWEEN ESCHERICHIA COLI 0157 AND OTHER SPECIES OF THE GENUS ESCHERICHIA  

EPA Science Inventory

Escherichia hermannii, a sorbitol-negative species of the genus Escherichia, has been reported to be agglutinated by Escherichia coli 0157 and four sorbitol-negative species of the genus Escherichia: . hermannii (24 isolates), Escherichia fergusonii (12 isolates), Escherichia vul...

32

Improvement of Escherichia coli growth by kaolinite  

Microsoft Academic Search

Knowledge of the impacts of clay minerals on microorganisms is essential to a complete understanding of microbially-mediated processes. Information available in this regard remains scarce. Using Escherichia coli (E. coli) as a model bacterium, we investigated the effect of kaolinite on various growth parameters. This clay mineral significantly affected maximal growth rate and yield of the E. coli-strain (MG 1655)

Elise Courvoisier; Sam Dukan

2009-01-01

33

Immunity to Enterotoxigenic Escherichia coli  

PubMed Central

Enterotoxigenic Escherichia coli strains represent the most frequent etiological agent of travelers diarrhea. Challenge studies with several of these strains were undertaken in volunteers to evaluate the mechanisms of disease-induced immunity. Seventeen students and other community volunteers were given 106 or 108 organisms of E. coli B7A (O148:H28), which produces heat-labile and heat-stable enterotoxins. Ten individuals developed diarrheal illness closely resembling natural travelers diarrhea; of these ten, rises in titer of serum antitoxin and anti-O antibody occurred in eight (80%). Eight of the volunteers who developed diarrhea in the first test agreed to undergo rechallenge 9 weeks later with 108 B7A organisms. Only one of these eight “veterans” developed diarrhea versus seven of twelve controls given the same challenge (P = 0.05). Despite clinical protection, all “veterans” excreted B7A after rechallenge. Four controls who developed diarrhea during the homologous B7A rechallenge test were rechallenged 9 weeks later with 109 organisms of E. coli strain E2528-C1 (O25:H-), which produces only heat-labile enterotoxin and possesses a different O, H, and pili antigen composition than B7A. Three of four “veterans” and two of six controls developed comparable diarrhea. These studies demonstrate that prior disease due to enterotoxigenic E. coli confers homologous immunity against subsequent challenge, and the operative mechanism apparently is not bactericidal and is not mediated by serum anti-O antibodies. Heterologous protection was not conferred where the only common antigen was heat-labile enterotoxin, indicating that serum infection-derived antitoxin to heat-labile enterotoxin also is not protective. PMID:378834

Levine, Myron M.; Nalin, David R.; Hoover, David L.; Bergquist, Erick J.; Hornick, Richard B.; Young, Charles R.

1979-01-01

34

Nonchemotactic Mutants of Escherichia coli  

PubMed Central

We have isolated 40 mutants of Escherichia coli which are nonchemotactic as judged by their failure to swarm on semisolid tryptone plates or to make bands in capillary tubes containing tryptone broth. All the mutants have normal flagella, a fact shown by their shape and reaction with antiflagella serum. All are fully motile under the microscope and all are sensitive to the phage chi. Unlike its parent, one of the mutants, studied in greater detail, failed to show chemotaxis toward oxygen, glucose, serine, threonine, or aspartic acid. The failure to exhibit chemotaxis does not result from a failure to use the chemicals. The swimming of this mutant was shown to be random. The growth rate was normal under several conditions, and the growth requirements were unchanged. Images PMID:5335897

Armstrong, John B.; Adler, Julius; Dahl, Margaret M.

1967-01-01

35

Vinylglycolate resistance in Escherichia coli.  

PubMed Central

Escherichia coli K-12 vinylglycolate-resistant mutants have been isolated and characterized. Two of the mutants, JSH 150 and JSH 151, have been determined to be double mutants, lacking both membrane-bound L-and D-lactate dehydrogenases. The lactate transport system is intact in all strains; both radioactive lactate and vinylglycolate are actively taken up. Likewise, the phosphoenolypyruvate-dependent phosphotransferase system for hexose uptake is active. Vinylglycolate, previously shown to inhibit the phosphoenolpyruvate-dependent phosphotransferase system, has very little effect in the double mutants. The extent of vinylglycolate inhibition in other mutants seems directly related to the activity of the lactate dehydrogenases. This indicates that vinylglycolate is oxidized to 2-keto-3-butenoate before inactivating the phosphoenolpyruvate-dependent phosphotransferase system. These results were found in whole cells and confirmed in isolated membrane vesicles. PMID:1090585

Shaw, L; Grau, F; Kaback, H R; Hong, J S; Walsh, C

1975-01-01

36

Curr Top Microbiol Immunol . Author manuscript Escherichia coli biofilms  

E-print Network

; growth & development ; Escherichia coli Infections ; microbiology ; Escherichia coli K12 ; physiologyCurr Top Microbiol Immunol . Author manuscript Page /1 20 Escherichia coli biofilms Christophe of the gastrointestinal tract. Both its frequentEscherichia coli community lifestyle and the availability of a wide array

Paris-Sud XI, Université de

37

LETTERS Escherichia coli Producing CMY-2  

E-print Network

to various antimicrobial drugs are rapidly increasing in Escherichia coli, not only in health care settings but also in the community. The food supply is suspected as a potential source of antimicrobial-resistant E. coli strains, which include cephalosporin-resistant E. coli found in retail meat products and other types of food (1). We reported a high prevalence of cephalosporin-resistant E. coli, most of which produced CMY-2 ?-lactamase, among retail poultry products in

?-lactamase In

38

Chemical Organizations in the Central Sugar Metabolism of Escherichia Coli  

E-print Network

1 Chemical Organizations in the Central Sugar Metabolism of Escherichia Coli Florian Centler, network analysis, stoichiometry, systems biology, sugar metabolism, Escherichia coli 1.1 Introduction in E. coli including gene expression, signal transduction, and enzymatic activities, some organizations

Dittrich, Peter

39

Recombinant collagen production optimization in Escherichia coli  

E-print Network

An Escherichia coli-based collagen-production process was used to investigate several process optimization objectives for use at the industrial scale. The effect of cooling on fermentation growth kinetics was studied, with ...

Whittemore, Brett A

2005-01-01

40

Starvation and outgrowth response in Escherichia coli  

E-print Network

In order to better understand the mechanisms that graphics. enable Escherichia coli to survive periods of starvation and then resume growth upon addition of nutrients, different aspects of starvation and recovery have been studied. To study...

Holland, Jill Diane

2012-06-07

41

Designed Potent Multivalent Chemoattractants for Escherichia coli$  

E-print Network

Designed Potent Multivalent Chemoattractants for Escherichia coli$ Jason E. Gestwicki, Laura E small molecules (i.e., carbohydrates, amino acids) interact with bacterial chemoreceptors. Although bacterial chemotaxis has been the subject of intense investigations, few have explored the influence

Cairo, Christopher W.

42

Structure of Escherichia Coli Tryptophanase  

SciTech Connect

Pyridoxal 5'-phosphate (PLP) dependent tryptophanase has been isolated from Escherichia coli and its crystal structure has been determined. The structure shares the same fold with and has similar quaternary structure to Proteus vulgaris tryptophanase and tyrosine-phenol lyase, but is found in a closed conformation when compared with these two enzymes. The tryptophanase structure, solved in its apo form, does not have covalent PLP bound in the active site, but two sulfate ions. The sulfate ions occupy the phosphoryl-binding site of PLP and the binding site of the {alpha}-carboxyl of the natural substrate tryptophan. One of the sulfate ions makes extensive interactions with both the transferase and PLP-binding domains of the protein and appears to be responsible for holding the enzyme in its closed conformation. Based on the sulfate density and the structure of the P. vulgaris enzyme, PLP and the substrate tryptophan were modeled into the active site. The resulting model is consistent with the roles of Arg419 in orienting the substrate to PLP and acidifying the {alpha}-proton of the substrate for {beta}-elimination, Lys269 in the formation and decomposition of the PLP quinonoid intermediate, Arg230 in orienting the substrate-PLP intermediates in the optimal conformation for catalysis, and His463 and Tyr74 in determining substrate specificity and suggests that the closed conformation observed in the structure could be induced by substrate binding and that significant conformational changes occur during catalysis. A catalytic mechanism for tryptophanase is proposed. Since E. coli tryptophanase has resisted forming diffraction-quality crystals for many years, the molecular surface of tryptophanase has been analyzed in various crystal forms and it was rationalized that strong crystal contacts occur on the flat surface of the protein and that the size of crystal contact surface seems to correlate with the diffraction quality of the crystal.

Ku,S.; Yip, P.; Howell, P.

2006-01-01

43

Escherichia coli survival in waters: Temperature dependence  

EPA Science Inventory

Knowing the survival rates of water-borne Escherichia coli is important in evaluating microbial contamination and making appropriate management decisions. E. coli survival rates are dependent on temperature, a dependency that is routinely expressed using an analogue of the Q10 mo...

44

The population genetics of commensal Escherichia coli  

Microsoft Academic Search

The primary habitat of Escherichia coli is the vertebrate gut, where it is the predominant aerobic organism, living in symbiosis with its host. Despite the occurrence of recombination events, the population structure is predominantly clonal, allowing the delineation of major phylogenetic groups. The genetic structure of commensal E. coli is shaped by multiple host and environmental factors, and the determinants

Olivier Tenaillon; David Skurnik; Bertrand Picard; Erick Denamur

2010-01-01

45

Engineering a Reduced Escherichia coli Genome  

Microsoft Academic Search

Our goal is to construct an improved Escherichia coli to serve both as a better model organism and as a more useful technological tool for genome science. We developed techniques for precise genomic surgery and applied them to deleting the largest K-islands of E. coli, identified by comparative genomics as recent horizontal acquisitions to the genome. They are loaded with

Vitaliy Kolisnychenko; Guy Plunkett; Christopher D. Herring; Tamás Fehér; János Pósfai; Frederick R. Blattner; György Pósfai

2002-01-01

46

Transcriptional proofreading in Escherichia coli.  

PubMed Central

A novel transcriptional proofreading mechanism associated with the beta-subunit of wild-type RNA polymerase from Escherichia coli is suggested from the following data. The purified holoenzyme contains an NTPase activity which specifically converts noncognate NTPs to their corresponding NDP in a template-dependent manner during in vitro transcription of synthetic single- and double-stranded templates. In contrast, purified enzyme from an rpoB mutant which shows increased transcriptional error lacked template-dependent NTP hydrolytic activity. The NTP hydrolytic activity of wild-type enzyme was critically dependent on the integrity of the initiation complex, and required continued transcriptional elongation. Transcription and translation of the lacZ gene proceeded 17% faster in the mutant than in its wild-type parent. These results are discussed in terms of a proofreading model in which the rate of transcription is limited by proofreading events that involve recognition and hydrolysis of noncognate NTPs before they can be misincorporated into RNA. Images PMID:2555156

Libby, R T; Nelson, J L; Calvo, J M; Gallant, J A

1989-01-01

47

Original article Effect of bacteriophage DC22 on Escherichia coli  

E-print Network

Original article Effect of bacteriophage DC22 on Escherichia coli O157:H7 in an artificial rumen -- The effect of a bacteriophage, DC22, on the survival of Escherichia coli O157:H7 in an artificial rumen of 105 PFU of DC22/CFU of E. coli O157:H7 (P Escherichia coli O157:H7 persisted in the control

Boyer, Edmond

48

Carbon nutrition of Escherichia coli in the mouse intestine  

E-print Network

Escherichia coli MG1655 genes induced by growth on mucus, conditions designed to mimic nutrient availabilityCarbon nutrition of Escherichia coli in the mouse intestine Dong-Eun Chang*, Darren J. Smalley E. coli pathogens in some individuals and a barrier to infection in others. Escherichia coli

Conway, Tyrrell

49

EM2006K-33 revised Identification of forces shaping the commensal Escherichia coli  

E-print Network

1 EM2006K-33 revised Identification of forces shaping the commensal Escherichia coli genetic title: Commensal Escherichia coli ecological structure Key words: Escherichia coli, commensal, animal forces shaping the Escherichia coli intraspecies ecological structure, we have characterized in terms

50

Clinical Implications of Enteroadherent Escherichia coli  

PubMed Central

Pathogenic Escherichia coli that colonize the small intestine primarily cause gastrointestinal illness in infants and travelers. The main categories of pathogenic E. coli that colonize the epithelial lining of the small intestine are enterotoxigenic E. coli enteropathogenic E. coli and enteroaggregative E. coli. These organisms accomplish their pathogenic process by a complex, coordinated multistage strategy, including non-intimate adherence mediated by various adhesins. These so called “enteroadherent E. coli ” categories subsequently produced toxins or effector proteins that are either secreted to the milieu or injected to the host cell. Finally, destruction of the intestinal microvilli results from the intimate adherence or the toxic effect exerted over the epithelia, resulting in water secretion and diarrhea. In this review, we summarize the current state of knowledge regarding these enteroadherent E. coli strains and the present clinical understanding of how these organisms colonize the human intestine and cause disease. PMID:22798032

Arenas-Hernandez, Margarita M.P.; Martinez-Laguna, Ygnacio; Torres, Alfredo G.

2012-01-01

51

Escherichia coli growth under modeled reduced gravity  

Microsoft Academic Search

Bacteria exhibit varying responses to modeled reduced gravity that can be simulated by clino-rotation. WhenEscherichia coli was subjected to different rotation speeds during clino-rotation, significant differences between modeled reduced gravity\\u000a and normal gravity controls were observed only at higher speeds (30–50 rpm). There was no apparent affect of removing samples\\u000a on the results obtained. WhenE. coli was grown in minimal

Paul W. Baker; Michelle L. Meyer; Laura G. Leff

2004-01-01

52

Escherichia coli O157 Cluster Evaluation  

PubMed Central

We investigated a multistate cluster of Escherichia coli O157:H7 isolates; pulsed-field gel electrophoresis subtyping, using a single enzyme, suggested an epidemiologic association. An investigation and additional subtyping, however, did not support the association. Confirmating E. coli O157 clusters with two or more restriction endonucleases is necessary before public health resources are allocated to follow-up investigations. PMID:15504278

Hunter, Susan B.; Bidol, Sally A.; Dietrich, Stephen; Kincaid, Jennifer; Salehi, Ellen; Nicholson, Lisa; Genese, Carol Ann; Todd-Weinstein, Sarah; Marengo, Lisa; Kimura, Akiko C.; Brooks, John T.

2004-01-01

53

Native valve Escherichia coli endocarditis following urosepsis  

PubMed Central

Gram-negative organisms are a rare cause of infective endocarditis. Escherichia coli, the most common cause of urinary tract infection and gram-negative septicemia involves endocardium rarely. In this case report, we describe infection of native mitral valve by E. coli following septicemia of urinary tract origin in a diabetic male; subsequently, he required prosthetic tissue valve replacement indicated by persistent sepsis and congestive cardiac failure. PMID:23814428

Rangarajan, D.; Ramakrishnan, S.; Patro, K. C.; Devaraj, S.; Krishnamurthy, V.; Kothari, Y.; Satyaki, N.

2013-01-01

54

Secretory Production of Human Leptin in Escherichia coli  

E-print Network

Secretory Production of Human Leptin in Escherichia coli Ki Jun Jeong, Sang Yup Lee Department homeostasis. In this study, human leptin was pro- duced and secreted efficiently in Escherichia coli using peptide; secre- tion; DsbA; Escherichia coli; protein production INTRODUCTION Human leptin, the product

55

Proteomic analysis of thioredoxin-targeted proteins in Escherichia coli  

E-print Network

Proteomic analysis of thioredoxin-targeted proteins in Escherichia coli Jaya K. Kumar, Stanley present a comprehensive analysis of the thioredoxin-linked Escherichia coli proteome by using tandem in a reaction catalyzed by thioredoxin reductase (4). Originally isolated from Escherichia coli in 1964

Richardson, Charles C.

56

Poly(3-hydroxybutyrate) production from xylose by recombinant Escherichia coli  

E-print Network

Poly(3-hydroxybutyrate) production from xylose by recombinant Escherichia coli Sang Yup Lee Abstract Several recombinant Escherichia coli strains harboring the Alcaligenes eutrophus and methods 2.1 Bacterial strains and plasmids Escherichia coli strains used were B (ATCC 11303), B (DSM 499

57

SHORT COMMUNICATION Occurrence of verocytotoxin-producing Escherichia coli  

E-print Network

SHORT COMMUNICATION Occurrence of verocytotoxin-producing Escherichia coli in the faeces of free Verocytotoxin-producing Escherichia coli (VTEC) is an important group of emerging food-borne pathogens of programmes for controlling VTEC at the farm level. Keywords Verocytotoxin-producing Escherichia coli (VTEC

Paris-Sud XI, Université de

58

Miniseries: Illustrating the Machinery of Life Escherichia coli*  

E-print Network

Miniseries: Illustrating the Machinery of Life Escherichia coli* Received for publication, August that support a recent textbook illustration of an Escherichia coli cell. The image magnifies a portion of life.'' This is how I began my 1991 article that presented several illustrations of Escherichia coli [1

Economou, Tassos

59

Light-powering Escherichia coli with proteorhodopsin Jessica M. Walter*  

E-print Network

Light-powering Escherichia coli with proteorhodopsin Jessica M. Walter* , Derek Greenfield respira- tion is inhibited by depleting oxygen or by the respiratory poison azide, Escherichia coli cells cellular pmf and, thus, viability. Proteorhodopsin allows Escherichia coli cells to withstand environmental

Liphardt, Jan

60

Influence of autoinducer 2 (ai-2) and ai-2-like inhibitors generated from ground beef on escherichia coli o157:h7 protein expression  

E-print Network

contains compounds that can interfere with AI-2-mediated bioluminescence expression in Vibrio. harveyi. The underlying hypothesis of this work was that AI-2 molecules affect the protein expression in Escherichia coli O157:H7 and AI-2 inhibitory molecules...

Soni, Kamleshkumar A.

2009-05-15

61

Automatic Tracking of Escherichia Coli Bacteria , Shahid Khan2 3  

E-print Network

bacteria (E. coli), which can generally cause several intestinal and extra-intestinal infections such as urinary tract infections, meningitis, and peritoni- tis. Escherichia coli chemotaxis has been the system of Escherichia Coli Bacteria 825 Fig. 1. (Left) A typical view of E. coli bacteria under a phase

Central Florida, University of

62

Engineering ethanologenic Escherichia coli for levoglucosan utilization  

Microsoft Academic Search

Levoglucosan is a major product of biomass pyrolysis. While this pyrolyzed biomass, also known as bio-oil, contains sugars that are an attractive fermentation substrate, commonly-used biocatalysts, such as Escherichia coli, lack the ability to metabolize this anhydrosugar. It has previously been shown that recombinant expression of the levoglucosan kinase enzyme enables use of levoglucosan as carbon and energy source. Here,

Donovan S. Layton; Avanthi Ajjarapu; Dong Won Choi; Laura R. Jarboe

2011-01-01

63

Functional proteomics in Escherichia coli  

E-print Network

-state of E. coli corresponding to hundreds of unique gene products. The copurification of proteins when fractionated at varying pHs could suggest the components of higher order complexes. This non-denaturing proteomic approach should provide physiological...

Champion, Matthew Maurice

2006-04-12

64

FTIR nanobiosensors for Escherichia coli detection  

PubMed Central

Summary Infections due to enterohaemorrhagic E. coli (Escherichia coli) have a low incidence but can have severe and sometimes fatal health consequences, and thus represent some of the most serious diseases due to the contamination of water and food. New, fast and simple devices that monitor these pathogens are necessary to improve the safety of our food supply chain. In this work we report on mesoporous titania thin-film substrates as sensors to detect E. coli O157:H7. Titania films treated with APTES ((3-aminopropyl)triethoxysilane) and GA (glutaraldehyde) were functionalized with specific antibodies and the absorption properties monitored. The film-based biosensors showed a detection limit for E. coli of 1 × 102 CFU/mL, constituting a simple and selective method for the effective screening of water samples. PMID:23019542

Greppi, Gianfranco; Marongiu, Maria Laura; Roggero, Pier Paolo; Ravindranath, Sandeep P; Mauer, Lisa J; Schibeci, Nicoletta; Perria, Francesco; Piccinini, Massimo; Innocenzi, Plinio; Irudayaraj, Joseph

2012-01-01

65

Dissolution of Silver Nanowires and Nanospheres Dictates Their Toxicity to Escherichia coli  

PubMed Central

Silver nanoparticles are extensively used in antibacterial applications. However, the mechanisms of their antibacterial action are not yet fully explored. We studied the solubility-driven toxicity of 100 × 6100?nm (mean primary diameter × length) silver nanowires (NWs) to recombinant bioluminescent Escherichia coli as a target representative of enteric pathogens. The bacteria were exposed to silver nanostructures in water to exclude the speciation-driven alterations. Spherical silver nanoparticles (83?nm mean primary size) were used as a control for the effect of NPs shape. Toxicity of both Ag NWs and spheres to E. coli was observed at similar nominal concentrations: the 4h EC50 values, calculated on the basis of inhibition of bacterial bioluminescence, were 0.42?±?0.06 and 0.68?±?0.01?mg Ag/L, respectively. Dissolution and bioavailability of Ag from NWs and nanospheres, analyzed with AAS or Ag-sensor bacteria, respectively, suggested that the toxic effects were caused by solubilized Ag+ ions. Moreover, the antibacterial activities of Ag NWs suspension and its ultracentrifuged particle-free supernatant were equal. The latter indicated that the toxic effects of ~80–100?nm Ag nanostructures to Escherichia coli were solely dependent on their dissolution and no shape-induced/related effects were observed. Yet, additional nanospecific effects could come into play in case of smaller nanosilver particles. PMID:24024212

Kunnis-Beres, Kai; Kahru, Anne; Ivask, Angela

2013-01-01

66

Detection of Escherichia coli O157 and Escherichia coli O157:H7 by the  

E-print Network

This study was conducted to investigate the presence of Escherichia (E.) coli O157 and E. coli O157:H7 and stx1 and stx2 genes on cattle carcasses and in rectal samples collected from Samsun Province of Turkey. A total of 200 samples collected from cattle carcasses and the rectal contents of 100 slaughtered cattle from two commercial abattoirs were tested using the immunomagnetic separation technique and multiplex PCR methods. E. coli O157 and E. coli O157:H7 were detected in 52 of the 200 samples (26%) tested. Of the positive samples, 49 were E. coli O157 and three were E. coli O157:H7. The E. coli O157 strain was isolated from 24 carcasses and 25 rectal samples, while E. coli O157:H7 was isolated from two carcasses and one rectal sample. Of the 49 samples positive for E. coli O157, 32 were from the rectal and carcass samples of the same animal, while two E. coli O157:H7 isolates were obtained from rectal swabs and carcasses of the same animal. The stx1 and stx2 genes were both detected in 35 E. coli O157 isolates and one E. coli O157:H7 isolate, but the stx2 gene was only detected alone in two E. coli O157 isolates. Overall, 16 carcasses tested positive for E. coli O157 and one carcass tested positive for E. coli O157:H7 based on both carcass and rectal samples. Overall, the results of this study indicate that cattle carcasses pose a potential risk to human health due to contamination by E. coli O157 and E. coli O157:H7 in the feces. Keywords: carcass, cattle, E. coli O157, E. coli O157:H7, rectum, stx1, stx2

Gökhan Inat; Belgin Siriken

2010-01-01

67

Large plasmids of avian Escherichia coli isolates.  

PubMed

The plasmid DNA of 30 Escherichia coli isolates from chickens was extracted and examined using techniques designed to isolate large plasmids. This plasmid DNA was examined for the presence of certain known virulence-related genes including cvaC, traT, and some aerobactin-related sequences. Seventeen of the 30 isolates contained from one to four plasmids greater than 50 kb in size. Eleven of these 17 strains possessed plasmids greater than 100 kb in size. Therefore, E. coli isolates of chickens frequently contain large plasmids, and many of these plasmids are likely to contain virulence-related sequences. PMID:8980827

Doetkott, D M; Nolan, L K; Giddings, C W; Berryhill, D L

1996-01-01

68

Hydrogen production by recombinant Escherichia coli strains  

PubMed Central

Summary The production of hydrogen via microbial biotechnology is an active field of research. Given its ease of manipulation, the best?studied bacterium Escherichia coli has become a workhorse for enhanced hydrogen production through metabolic engineering, heterologous gene expression, adaptive evolution, and protein engineering. Herein, the utility of E.?coli strains to produce hydrogen, via native hydrogenases or heterologous ones, is reviewed. In addition, potential strategies for increasing hydrogen production are outlined and whole?cell systems and cell?free systems are compared. PMID:21895995

Maeda, Toshinari; Sanchez-Torres, Viviana; Wood, Thomas K.

2012-01-01

69

Controlling the Shape of Filamentous Cells of Escherichia coli  

E-print Network

Controlling the Shape of Filamentous Cells of Escherichia coli Shoji Takeuchi,, Willow R. Di of Escherichia coli with defined shapes, including crescents, zigzags, sinusoids, and spirals. The procedure into solution. This paper describes a technique for controlling the shape of filamentous cells of Escherichia

Weibel, Douglas B.

70

Genetic architecture of thermal adaptation in Escherichia coli  

E-print Network

Genetic architecture of thermal adaptation in Escherichia coli Michelle M. Riehle*, Albert F make genomewide surveys more tractable. Six lines of Escherichia coli adapted for 2,000 generations events. Three of the duplications were at 2.85 Mb of the E. coli chromo- some, providing evidence

Bennett, Albert F.

71

Controlling biological systems: the lactose regulation system of Escherichia coli  

E-print Network

Controlling biological systems: the lactose regulation system of Escherichia coli A. Agung Julius, namely, the lactose regulation system of the Escherichia coli bacteria. The conceptual idea behind hybrid model of the lactose regulation system of E. coli bacteria that capture important phenomena which

Pappas, George J.

72

EXPERIMENTAL ESCHERICHIA COLI DIARRHOEA IN COLOSTRUM DEPRIVED LAMBS  

E-print Network

EXPERIMENTAL ESCHERICHIA COLI DIARRHOEA IN COLOSTRUM DEPRIVED LAMBS Marion DUCHET-SUCHAUX, Anne Escherichia coli (ETEC), is an important cause of mortality in calves, lambs and piglets. ETEC strains) élevés conventionnellement sans colostrum ont été inoculés par voie orale avec 1,7 à 3,1 x 108 E. coli B

Boyer, Edmond

73

Original article Inhibition of Escherichia coli O157:H7  

E-print Network

Original article Inhibition of Escherichia coli O157:H7 in commercial and traditional fermented and indigenous lactic acid bacteria (LAB) and the survival of Escherichia coli O157:H7 in fermented goat's milk to growth and acid production. However, E. coli O157:H7 was inhibited in the LP-activated milk

Paris-Sud XI, Université de

74

ORIGINAL ARTICLE Escherichia coli transcription factor YncC  

E-print Network

ORIGINAL ARTICLE Escherichia coli transcription factor YncC (McbR) regulates colanic acid, USA Quorum-sensing signal autoinducer 2 (AI-2) stimulates Escherichia coli biofilm formation through synthase LuxS and B3023 repressed yncC. MqsR has a toxic effect on E. coli bacterial growth, which

Wood, Thomas K.

75

Probing the Performance Limits of the Escherichia coli Metabolic Network  

E-print Network

Probing the Performance Limits of the Escherichia coli Metabolic Network Subject to Gene Additions to a linear flux balance analysis (FBA) Escherichia coli model. Both the gene addition problem of optimally necessary to achieve maximum biomass production in E. coli is determined for aerobic growth on glucose

Maranas, Costas

76

Response of Escherichia coli growth rate to osmotic shock  

E-print Network

Response of Escherichia coli growth rate to osmotic shock Enrique Rojasa,b,c , Julie A. Theriotb monitored the elongation of single Escherichia coli cells while rapidly chang- ing the osmolarity- and hypoosmotic shock, E. coli cells resumed their preshock growth rate and relaxed to their steady-state rate

Das, Rhiju

77

Characterization of enteroaggregative Escherichia coli isolates  

Microsoft Academic Search

Forty enteraggregative Escherichia coli (EAggEC) previously characterized by their ability to adhere to HEp-2 cells or\\/and their hybridization with the 1-kb EAggEC DNA probe were investigated for the presence of adherence factors and heat-stable enterotoxin (EAST1)-encoding genes. Only 45% of the isolates harbored the EAST1-encoding genes as detected by polymerase chain reaction. None of them hybridized with an AAF\\/II-encoding gene

Chantal Rich; Sabine Favre-Bonte; Frédéric Sapena; Bernard Joly; Christiane Forestier

1999-01-01

78

Action of sodium deoxycholate on Escherichia coli  

SciTech Connect

Sodium deoxycholate is used in a number of bacteriological media for the isolation and classification of gram-negative bacteria from food and the environment. Initial experiments to study the effect of deoxycholate on the growth parameters of Escherichia coli showed an increase in the lag time constant and generation time and a decrease in the growth rate constant total cell yield of this microorganisms. Cell fractionation studies indicated that sodium deoxycholate at levels used in bacteriological media interferes with the incorporation of (U-/sup 14/C)glucose into the cold-trichloroacetic acid-soluble, ethanol-soluble, and trypsin-soluble cellular fractions of E. coli. Finally, sodium deoxycholate interfered with the flagellation and motility of Proteus mirabilis and E. coli. It would appear then that further improvement of the deoxycholate medium may be in order.

D'Mello, A.; Yotis, W.W.

1987-08-01

79

Biodegradation of Aromatic Compounds by Escherichia coli  

PubMed Central

Although Escherichia coli has long been recognized as the best-understood living organism, little was known about its abilities to use aromatic compounds as sole carbon and energy sources. This review gives an extensive overview of the current knowledge of the catabolism of aromatic compounds by E. coli. After giving a general overview of the aromatic compounds that E. coli strains encounter and mineralize in the different habitats that they colonize, we provide an up-to-date status report on the genes and proteins involved in the catabolism of such compounds, namely, several aromatic acids (phenylacetic acid, 3- and 4-hydroxyphenylacetic acid, phenylpropionic acid, 3-hydroxyphenylpropionic acid, and 3-hydroxycinnamic acid) and amines (phenylethylamine, tyramine, and dopamine). Other enzymatic activities acting on aromatic compounds in E. coli are also reviewed and evaluated. The review also reflects the present impact of genomic research and how the analysis of the whole E. coli genome reveals novel aromatic catabolic functions. Moreover, evolutionary considerations derived from sequence comparisons between the aromatic catabolic clusters of E. coli and homologous clusters from an increasing number of bacteria are also discussed. The recent progress in the understanding of the fundamentals that govern the degradation of aromatic compounds in E. coli makes this bacterium a very useful model system to decipher biochemical, genetic, evolutionary, and ecological aspects of the catabolism of such compounds. In the last part of the review, we discuss strategies and concepts to metabolically engineer E. coli to suit specific needs for biodegradation and biotransformation of aromatics and we provide several examples based on selected studies. Finally, conclusions derived from this review may serve as a lead for future research and applications. PMID:11729263

Diaz, Eduardo; Ferrandez, Abel; Prieto, Maria A.; Garcia, Jose L.

2001-01-01

80

Salmonella typhimurium intercepts Escherichia coli signaling to enhance antibiotic tolerance  

E-print Network

Salmonella typhimurium intercepts Escherichia coli signaling to enhance antibiotic tolerance Nicole Salmonella typhimurium increases its antibiotic toler- ance in response to indole, even though S. typhimurium

Collins, James J.

81

The Genetic Basis of Escherichia coli Pathoadaptation to Macrophages  

E-print Network

of the E. coli yrfF gene. Moreover, transposition of the IS186 element into the promoter of Lon gene fast, and through how many adaptive steps, a commensal Escherichia coli (E. coli) acquire, as suggested from a mathematical model, which reproduces the observed experimental dynamics of E. coli

Magalhães, Sara

82

Insights on Escherichia coli biofilm formation and inhibition from whole-transcriptome profiling  

E-print Network

Minireview Insights on Escherichia coli biofilm formation and inhibition from whole with the best- characterized strain, Escherichia coli. Investigations of biofilm formation and inhibition). Escherichia coli biofilm development is a complex process that leads to beautiful structures (Fig. 1

Wood, Thomas K.

83

Construction and Optimization of Mevalonate Pathway for Production of Isoprenoids in Escherichia coli  

E-print Network

Escherichia coli evolve to computationally predicted growthF.G. , B. Growth-rate recovery of Escherichia coli culturesEscherichia coli K-12 undergoes adaptive evolution to achieve in silico predicted optimal growth.

Nowroozi, Farnaz F.B.

2010-01-01

84

Survival of multi-drug resistant enteropathogenic Escherichia coli and Salmonella paratyphi in Vembanadu  

E-print Network

Survival of multi-drug resistant enteropathogenic Escherichia coli and Salmonella paratyphi the survival response of multi-drug resistant enteropathogenic Escherichia coli and Salmonella paratyphi- otypes of Escherichia coli, Salmonella enterica typhi and paratyphi are highly endemic to India

Mazumder, Asit

85

Intestinal immunisation with Escherichia coli protects rats against Escherichia coli induced cholangitis.  

PubMed Central

BACKGROUND: Cholangitis, an infection of the biliary tract, is most commonly caused by Gram negative bacteria, particularly Escherichia coli. Factors governing the severity of cholangitis, including the role of biliary IgA, are poorly understood. AIMS: The aim of this work was to find out if biliary IgA directed against E coli protects rats against hepatobiliary infection with E coli. SUBJECTS: Male Sprague-Dawley rats weighing 270-350 grams were used in all of the experiments. METHODS: At laparotomy, rats were immunised by injecting killed E coli or normal saline (controls) into Peyer's patches. With or without subsequent antigenic boosting (by oral administration of killed E coli), bile was collected at a second laparotomy, and rats were infected by introducing viable E coli into the bile duct. Production of IgA anti-E coli antibody was measured by enzyme linked immunosorbent assay of bile, and the presence of hepatobiliary infection was determined by quantitative culture of liver homogenates. RESULTS: Systemic infection was present in six of 12 control rats and in one of 24 immunised rats (p = 0.005) after death. There was an inverse correlation between immunisation and E coli colony counts in cultured liver homogenates (p = 0.024). CONCLUSION: The findings suggest that biliary IgA directed against E coli protected rats against hepatobiliary E coli infection and systemic sepsis. Images Figure 2 PMID:8881825

Aagaard, B D; Heyworth, M F; Oesterle, A L; Jones, A L; Way, L W

1996-01-01

86

An isochorismate hydroxymutase isogene in Escherichia coli.  

PubMed

The pivotal step in enterobactin and menaquinone biosynthesis is the conversion of chorismate to isochorismate. Circumstantial evidence pointed to Escherichia coli isochorismate hydroxymutase isogenes being responsible for this conversion. While the gene involved in enterobactin synthesis (entC) was known, the corresponding gene for menaquinone biosynthesis (menF) was not but has now been identified and sequenced. The amino acid sequence of MenF is 23.5% identical and 57.8% similar to that of EntC. PMID:8549818

Müller, R; Dahm, C; Schulte, G; Leistner, E

1996-01-01

87

Fluoroquinolone-resistant Escherichia coli, Indonesia  

PubMed Central

In a recent, population-based survey of 3,996 persons in Indonesia, fluoroquinolone (FQ)-resistant Escherichia coli was prevalent in the fecal flora of 6% of patients at hospital admission and 23% of patients at discharge, but not among healthy relatives or patients visiting primary healthcare centers (2%). Molecular typing showed extensive genetic diversity with only limited clonality among isolates. This finding suggests that independent selection of resistant mutants occurs frequently. FQ-resistant isolates exhibited a higher rate of spontaneous mutation, but sparser virulence profiles, than FQ-susceptible isolates from the same population. The resistant isolates belonged predominantly to phylogenetic groups A (57%) and B1 (22%) but also to the moderately virulent group D (20%). Hypervirulent strains from the B2 cluster were underrepresented (1%). Because FQ-resistant E. coli can cause disease, especially nosocomial infections in immunocompromised patients, spread of such strains must be stopped. PMID:16229763

Kuntaman, Kuntaman; Lestari, Endang Sri; Severin, Juliette A.; Kershof, Irma M.; Mertaniasih, Ni Made; Purwanta, Marijam; Hadi, Usman; Johnson, James R.; Verbrugh, Henri A.

2005-01-01

88

Engineering ethanologenic Escherichia coli for levoglucosan utilization.  

PubMed

Levoglucosan is a major product of biomass pyrolysis. While this pyrolyzed biomass, also known as bio-oil, contains sugars that are an attractive fermentation substrate, commonly-used biocatalysts, such as Escherichia coli, lack the ability to metabolize this anhydrosugar. It has previously been shown that recombinant expression of the levoglucosan kinase enzyme enables use of levoglucosan as carbon and energy source. Here, ethanologenic E. coli KO11 was engineered for levoglucosan utilization by recombinant expression of levoglucosan kinase from Lipomyces starkeyi. Our engineering strategy uses a codon-optimized gene that has been chromosomally integrated within the pyruvate to ethanol (PET) operon and does not require additional antibiotics or inducers. Not only does this engineered strain use levoglucosan as sole carbon source, but it also ferments levoglucosan to ethanol. This work demonstrates that existing biocatalysts can be easily modified for levoglucosan utilization. PMID:21719279

Layton, Donovan S; Ajjarapu, Avanthi; Choi, Dong Won; Jarboe, Laura R

2011-09-01

89

Engineering the Escherichia coli Fermentative Metabolism  

NASA Astrophysics Data System (ADS)

Fermentative metabolism constitutes a fundamental cellular capacity for industrial biocatalysis. Escherichia coli is an important microorganism in the field of metabolic engineering for its well-known molecular characteristics and its rapid growth. It can adapt to different growth conditions and is able to grow in the presence or absence of oxygen. Through the use of metabolic pathway engineering and bioprocessing techniques, it is possible to explore the fundamental cellular properties and to exploit its capacity to be applied as industrial biocatalysts to produce a wide array of chemicals. The objective of this chapter is to review the metabolic engineering efforts carried out with E. coli by manipulating the central carbon metabolism and fermentative pathways to obtain strains that produce metabolites with high titers, such as ethanol, alanine, lactate and succinate.

Orencio-Trejo, M.; Utrilla, J.; Fernández-Sandoval, M. T.; Huerta-Beristain, G.; Gosset, G.; Martinez, A.

90

Investigation of Escherichia Coli bacteria growth process using electronic nose  

Microsoft Academic Search

In this study, the kind of Escherichia Coli obtained using gas sensor sequence consisted deneyler QCM (Quartz Crystal Microbalance) as experiments related to determining from the odour of growing duration of the bacteria. In this context, the growing duration of odour produced by Escherichia Coli bacteria was examined in five day period after 24, 48, 72, 96, 120 hours that

M. E. S?ahin; H. M. Saraog?lu

2010-01-01

91

Kefir grain tolerance to Escherichia coli contamination--industrial advantages  

E-print Network

NOTE Kefir grain tolerance to Escherichia coli contamination--industrial advantages Piotr / Published online: 21 August 2012 # INRA and Springer-Verlag, France 2012 Abstract Kefir grains are used the possibility of the re-use of kefir grains grown at 18 °C for 24 h in pasteurized Escherichia coli contaminated

Paris-Sud XI, Université de

92

DNA probe for detection of serogroup 0157 enterohemorrhagic Escherichia coli  

Microsoft Academic Search

To develop a probe for the detection of serogroup O157 enterohemorrhagic Escherichia coli (EHEC), plasmid DNA extracts from 16 E. coli strains that hybridized with the CVD419 probe were screened for restriction fragments present in plasmids of serogroup O157 E. coli strains, but not in plasmids of non-O157 E. coli strains. Using a single O157:H7 E. coli strain (6391), 10

Leslie G. Huck; C. Richard Dorn; Elisabeth J. Angrick

1995-01-01

93

www.postersession.com Characterization of the Omptin Protease, OmpT, in Escherichia coli  

E-print Network

printed by www.postersession.com Characterization of the Omptin Protease, OmpT, in Escherichia coli Escherichia coliEscherichia coli,, Shigella flexneriShigella flexneri,, Salmonella. ·· InIn E. coliE. coli, OmpT has been shown to cleave protamine, an antimicrobial pept, OmpT has been

Walker, Lawrence R.

94

Regulation of alcohol fermentation by Escherichia coli  

SciTech Connect

The purpose of this project is to elucidate the way in which the synthesis of ethanol and related fermentation products are regulated in the facultative anaerobe Escherichia coli. We are also investigating the control of other genes required for anaerobic growth. We have isolated both structural and regulatory mutations affecting the expression of alcohol dehydrogenase, the enzyme responsible for the final step in alcohol synthesis. Some of these regulatory mutations also affect other anaerobically induced genes. The adh gene has been cloned and sequenced. The ADH protein is one of the largest highly expressed proteins in E. coli and requires approximately 2700bp of DNA for its coding sequence. We have also isolated mutations affecting the fermentative lactate dehydrogenase and have recently cloned the ldh gene. In consequence it is now possible to construct E. coli strains defective in the production of any one or more of their normal fermentation products (i.e. formate, acetate, lactate, ethanol and succinate). The factors affecting ratio of fermentation products are being investigated by in vivo NMR spectroscopy.

Clark, D.P.

1990-01-01

95

Long term effects of Escherichia coli mastitis.  

PubMed

Escherichia coli is one of the most frequently diagnosed causes of bovine mastitis, and is typically associated with acute, clinical mastitis. The objective of the present study was to evaluate the long term effects of intramammary infections by E. coli on milk yield and quality, especially milk coagulation. Twenty-four Israeli Holstein cows diagnosed with clinical mastitis due to intramammary infection by E. coli were used in this study. Mean lactation number, days in milk (DIM) and daily milk yield (DMY) at the time of infection was 3.3 ± 1.3, 131.7 days ± 78.6 and 45.7 L ± 8.4, respectively. DMY, milk constituents, somatic cells count (SCC), differential leukocytes count and coagulation parameters were subsequently assessed. Two patterns of inflammation were identified: 'short inflammation', characterized by <15% decrease in DMY and <30 days until return to normal (n?=?5), and 'long inflammation', characterized by >15% decrease in DMY and >30 days to reach a new maximum DMY (n = 19). The estimated mean loss of marketable milk during the study was 200 L/cow for 'short inflammation' cases, and 1,500 L/cow for 'long inflammation' ones. Significant differences between 'short' and 'long inflammation' effects were found in almost all parameters studied. Long-term detrimental effects on milk quality were found regardless of clinical or bacteriological cure of affected glands. PMID:24906501

Blum, Shlomo E; Heller, Elimelech D; Leitner, Gabriel

2014-07-01

96

Sources of Escherichia coli in a Coastal Subtropical Environment  

Microsoft Academic Search

Sources of Escherichia coli in a coastal waterway located in Ft. Lauderdale, Fla., were evaluated. The study consisted of an extensive program of field measurements designed to capture spatial and temporal variations in E. coli concentrations as well as experiments conducted under laboratory-controlled conditions. E. coli from environmental samples was enumerated by using a defined substrate technology (Colilert-18). Field sampling

HELENA M. SOLO-GABRIELE; MELINDA A. WOLFERT; TIMOTHY R. DESMARAIS; CAROL J. PALMER

2000-01-01

97

Review article Secretion of virulence factors by Escherichia coli  

E-print Network

Review article Secretion of virulence factors by Escherichia coli Bernard China* Fréderic Goffaux with their host, pathogenic strains of E. coli need to secrete some virulence factors which can modify the metabolism of host cells, contributing to disease. Since E. coli is a Gram-negative bacteria, this secretion

Paris-Sud XI, Université de

98

CONFINEMENT BY BIASED VELOCITY JUMPS: AGGREGATION OF ESCHERICHIA COLI  

E-print Network

CONFINEMENT BY BIASED VELOCITY JUMPS: AGGREGATION OF ESCHERICHIA COLI VINCENT CALVEZ, GA¨EL RAOUL-attractors. The prototypical example is the bacterium Escheria coli, whose swimming pattern has been described as run, this stochastic process is biased upwards the gradient, although E. coli is too small to reliably measure

Schmeiser, Christian

99

Indole Transport across Escherichia coli Membranes ?  

PubMed Central

Indole has many, diverse roles in bacterial signaling. It regulates the transition from exponential to stationary phase, it is involved in the control of plasmid stability, and it influences biofilm formation, virulence, and stress responses (including antibiotic resistance). Its role is not restricted to bacteria, and recently it has been shown to include mutually beneficial signaling between enteric bacteria and their mammalian hosts. In many respects indole behaves like the signaling component of a quorum-sensing system. Indole synthesized within the producer bacterium is exported into the surroundings where its accumulation is detected by sensitive cells. A view often repeated in the literature is that in Escherichia coli the AcrEF-TolC and Mtr transporter proteins are involved in the export and import, respectively, of indole. However, the evidence for their involvement is indirect, and it has been known for a long time that indole can pass directly through a lipid bilayer. We have combined in vivo and in vitro approaches to examine the relative importance of protein-mediated transport and direct passage across the E. coli membrane. We conclude that the movement of indole across the E. coli membrane under normal physiological conditions is independent of AcrEF-TolC and Mtr. Furthermore, direct observation of individual liposomes shows that indole can rapidly cross an E. coli lipid membrane without the aid of any proteinaceous transporter. These observations not only enhance our understanding of indole signaling in bacteria but also provide a simple explanation for the ability of indole to signal between biological kingdoms. PMID:21296966

Pinero-Fernandez, S.; Chimerel, C.; Keyser, U. F.; Summers, D. K.

2011-01-01

100

Vibrio parahaemolyticus, enterotoxigenic Escherichia coli, enterohemorrhagic Escherichia coli and Vibrio cholerae  

PubMed Central

This review highlighted the following: (i) pathogenic mechanism of the thermostable direct hemolysin produced by Vibrio parahaemolyticus, especially on its cardiotoxicity, (ii) heat-labile and heat-stable enterotoxins produced by enterotoxigenic Escherichia coli, especially structure–activity relationship of heat-stable enterotoxin, (iii) RNA N-glycosidase activity of Vero toxins (VT1 and VT2) produced by enterohemorrhagic Escherichia coli O157:H7, (iv) discovery of Vibrio cholerae O139, (v) isolation of new variant of Vibrio cholerae O1 El Tor that carries classical ctxB, and production of high concentration of cholera toxin by these strains, and (vi) conversion of viable but nonculturable (VBNC) Vibrio cholerae to culturable state by co-culture with eukaryotic cells. PMID:21233598

TAKEDA, Yoshifumi

2011-01-01

101

Mechanism of Escherichia coli Resistance to Pyrrhocoricin  

PubMed Central

Due to their lack of toxicity to mammalian cells and good serum stability, proline-rich antimicrobial peptides (PR-AMPs) have been proposed as promising candidates for the treatment of infections caused by antimicrobial-resistant bacterial pathogens. It has been hypothesized that these peptides act on multiple targets within bacterial cells, and therefore the likelihood of the emergence of resistance was considered to be low. Here, we show that spontaneous Escherichia coli mutants resistant to pyrrhocoricin arise at a frequency of approximately 6 × 10?7. Multiple independently derived mutants all contained a deletion in a nonessential gene that encodes the putative peptide uptake permease SbmA. Sensitivity could be restored to the mutants by complementation with an intact copy of the sbmA gene. These findings question the viability of the development of insect PR-AMPs as antimicrobials. PMID:24590485

Narayanan, Shalini; Modak, Joyanta K.; Ryan, Catherine S.; Garcia-Bustos, Jose; Davies, John K.

2014-01-01

102

Intrahost genome alterations in enterohemorrhagic Escherichia coli.  

PubMed

Bacterial chromosomes are not fixed molecules; they evolve over the course of infections in human beings. During infection, a variety of strong selective pressures are exerted on the pathogen. The resulting genetic changes that occur in intestinal pathogens might influence clinical outcome and have an impact on diagnosis and epidemiology. Enterohemorrhagic Escherichia coli (EHEC) is a good example of this process. These zoonotic pathogens cause diarrhea, bloody diarrhea, and hemolytic uremic syndrome in human beings, whereas in their natural habitat they mostly are asymptomatic colonizers. Thus, EHEC must be able to quickly adapt from one milieu to another. The greatest challenge it might face is to infect human beings--profound chromosomal changes occur during the brief period that EHEC passes through the human gastrointestinal tract, leading to gains and losses of virulence determinants. The intensive study of human enteric factors that induce or modulate pathogen chromosome instability could provide important information about host-microbial interactions. PMID:19462505

Mellmann, Alexander; Bielaszewska, Martina; Karch, Helge

2009-05-01

103

Nucleoid release from Escherichia coli cells.  

PubMed Central

The time course of morphological changes during lysis of Escherichia coli cells was examined with respect to an undisturbed release of nucleoids. The addition of detergents to plasmolyzed, osmotic sensitive cells resulted in the immediate reversal of plasmolysis followed by the appearance of rod-shaped ghost cells without any detectable spheroplast formation. Electron microscopic examination of the rod-shaped ghost cells revealed a zonal gap in the cell envelope, allowing the free release of the nucleoid. Due to the high ionic strength, a suitable cell lysis was shown to require higher incubation temperatures. However, in the absence of an appropriate control this may result in the sphering and vesiculation of ghost cell envelopes and even the unfolding of released nucleoids. To avoid this unfavorable consequence of lysis at high temperatures, a microscopic examination on the course of rod-shaped ghost formation is suggested. Images PMID:342512

Materman, E C; Van Gool, A P

1978-01-01

104

Dispensability of Escherichia coli's latent pathways  

E-print Network

Gene-knockout experiments on single-cell organisms have established that expression of a substantial fraction of genes is not needed for optimal growth. This problem acquired a new dimension with the recent discovery that environmental and genetic perturbations of the bacterium Escherichia coli are followed by the temporary activation of a large number of latent metabolic pathways, which suggests the hypothesis that temporarily activated reactions impact growth and hence facilitate adaptation in the presence of perturbations. Here we test this hypothesis computationally and find, surprisingly, that the availability of latent pathways consistently offers no growth advantage, and tends in fact to inhibit growth after genetic perturbations. This is shown to be true even for latent pathways with a known function in alternate conditions, thus extending the significance of this adverse effect beyond apparently nonessential genes. These findings raise the possibility that latent pathway activation is in fact derivat...

Cornelius, Sean P; Motter, Adilson E; 10.1073/pnas.1009772108

2011-01-01

105

EcoCyc: Encyclopedia of Escherichia coli genes and metabolism  

Microsoft Academic Search

The encyclopedia of Escherichia coli genes and metabolism (EcoCyc) is a database that combines information about the genome and the intermediary metabolism of E.coli. The database describes 3030 genes of E.coli, 695 enzymes encoded by a subset of these genes, 595 metabolic reactions that occur in E.coli, and the organization of these reactions into 123 metabolic pathways. The EcoCyc graphical

Peter D. Karp; Monica Riley; Suzanne M. Paley; Alida Pellegrini-toole; Markus Krummenacker

1998-01-01

106

Eco Cyc: encyclopedia of Escherichia coli genes and metabolism  

Microsoft Academic Search

The encyclopedia of Escherichia coli genes andmetabolism (EcoCyc) is a database that combinesinformation about the genome and the intermediarymetabolism of E.coli. The database describes 3030genes of E.coli, 695 enzymes encoded by a subset ofthese genes, 595 metabolic reactions that occur inE.coli, and the organization of these reactions into 123metabolic pathways. The EcoCyc graphical user interfaceallows scientists to query and explore

Peter D. Karp; Monica Riley; Suzanne M. Paley; Alida Pellegrini-toole; Markus Krummenacker

1999-01-01

107

Influence of carbon-based nanomaterials on lux-bioreporter Escherichia coli.  

PubMed

The cytotoxic effects of carbon-based nanomaterials are evaluated via the induction of luminescent genetically engineered Escherichia coli bacterial cells. Specifically, two engineered E. coli bacteria strains of DPD2794 and TV1061 were incubated with aqueous dispersion of three carbon allotropes (multi-wall carbon nanotubes (MWCNTs), graphene nanosheets and carbon black nanopowders) with different concentrations and the resulting bioluminescence was recorded at 30°C and 25°C, respectively. The corresponding optical density changes of bacterial cells in the presence of various carbon nanomaterials were recorded as well. Based on these results, E. coli DPD2794 bacterial induction responds to a greater degree than E. coli TV1061 bacteria when exposed to various carbon-based nanomaterials. Finally, the surface morphology of E. coli DPD2794 bacteria cells before and after carbon-based nanomaterials treatment was observed using a field emission scanning electron microscope (FESEM), from which morphological changes from the presence of carbon-based nanomaterials were observed and discussed. PMID:24881555

Jia, Kun; Marks, Robert S; Ionescu, Rodica E

2014-08-01

108

Independence of replisomes in Escherichia coli chromosomalreplication  

SciTech Connect

In Escherichia coli DNA replication is carried out by the coordinated action of the proteins within a replisome. After replication initiation, the two bidirectionally oriented replisomes from a single origin are colocalized into higher-order structures termed replication factories. The factory model postulated that the two replisomes are also functionally coupled. We tested this hypothesis by using DNA combing and whole-genome microarrays. Nascent DNA surrounding oriC in single, combed chromosomes showed instead that one replisome, usually the leftward one, was significantly ahead of the other 70% of the time. We next used microarrays to follow replication throughout the genome by measuring DNA copy number. We found in multiple E. coli strains that the replisomes are independent, with the leftward replisome ahead of the rightward one. The size of the bias was strain-specific, varying from 50 to 130 kb in the array results. When we artificially blocked one replisome, the other continued unabated, again demonstrating independence. We suggest an improved version of the factory model that retains the advantages of threading DNA through colocalized replisomes at about equal rates, but allows the cell flexibility to overcome obstacles encountered during elongation.

Breier, Adam M.; Weier, Heinz-Ulrich G.; Cozzarelli, Nicholas R.

2005-03-13

109

Expanding ester biosynthesis in Escherichia coli.  

PubMed

To expand the capabilities of whole-cell biocatalysis, we have engineered Escherichia coli to produce various esters. The alcohol O-acyltransferase (ATF) class of enzyme uses acyl-CoA units for ester formation. The release of free CoA upon esterification with an alcohol provides the free energy to facilitate ester formation. The diversity of CoA molecules found in nature in combination with various alcohol biosynthetic pathways allows for the biosynthesis of a multitude of esters. Small to medium volatile esters have extensive applications in the flavor, fragrance, cosmetic, solvent, paint and coating industries. The present work enables the production of these compounds by designing several ester pathways in E. coli. The engineered pathways generated acetate esters of ethyl, propyl, isobutyl, 2-methyl-1-butyl, 3-methyl-1-butyl and 2-phenylethyl alcohols. In particular, we achieved high-level production of isobutyl acetate from glucose (17.2 g l(-1)). This strategy was expanded to realize pathways for tetradecyl acetate and several isobutyrate esters. PMID:24609358

Rodriguez, Gabriel M; Tashiro, Yohei; Atsumi, Shota

2014-04-01

110

Rates of transposition in Escherichia coli  

PubMed Central

The evolutionary role of transposable elements (TEs) is still highly controversial. Two key parameters, the transposition rate (u and w, for replicative and non-replicative transposition) and the excision rate (e) are fundamental to understanding their evolution and maintenance in populations. We have estimated u, w and e for six families of TEs (including eight members: IS1, IS2, IS3, IS4, IS5, IS30, IS150 and IS186) in Escherichia coli, using a mutation accumulation (MA) experiment. In this experiment, mutations accumulate essentially at the rate at which they appear, during a period of 80 500 (1610 generations × 50 lines) generations, and spontaneous transposition events can be detected. This differs from other experiments in which insertions accumulated under strong selective pressure or over a limited genomic target. We therefore provide new estimates for the spontaneous rates of transposition and excision in E. coli. We observed 25 transposition and three excision events in 50 MA lines, leading to overall rate estimates of u ? 1.15 × 10–5, w ? 4 × 10?8 and e ? 1.08 × 10?6 (per element, per generation). Furthermore, extensive variation between elements was found, consistent with previous knowledge of the mechanisms and regulation of transposition for the different elements. PMID:24307531

Sousa, Ana; Bourgard, Catarina; Wahl, Lindi M.; Gordo, Isabel

2013-01-01

111

Concerted control of Escherichia coli cell division  

PubMed Central

The coordination of cell growth and division is a long-standing problem in biology. Focusing on Escherichia coli in steady growth, we quantify cell division control using a stochastic model, by inferring the division rate as a function of the observable parameters from large empirical datasets of dividing cells. We find that (i) cells have mechanisms to control their size, (ii) size control is effected by changes in the doubling time, rather than in the single-cell elongation rate, (iii) the division rate increases steeply with cell size for small cells, and saturates for larger cells. Importantly, (iv) the current size is not the only variable controlling cell division, but the time spent in the cell cycle appears to play a role, and (v) common tests of cell size control may fail when such concerted control is in place. Our analysis illustrates the mechanisms of cell division control in E. coli. The phenomenological framework presented is sufficiently general to be widely applicable and opens the way for rigorous tests of molecular cell-cycle models. PMID:24550446

Osella, Matteo; Nugent, Eileen; Cosentino Lagomarsino, Marco

2014-01-01

112

Surface expression of ?-transaminase in Escherichia coli.  

PubMed

Chiral amines are important for the chemical and pharmaceutical industries, and there is rapidly growing interest to use transaminases for their synthesis. Since the cost of the enzyme is an important factor for process economy, the use of whole-cell biocatalysts is attractive, since expensive purification and immobilization steps can be avoided. Display of the protein on the cell surface provides a possible way to reduce the mass transfer limitations of such biocatalysts. However, transaminases need to dimerize in order to become active, and furthermore, they require the cofactor pyridoxal phosphate; consequently, successful transaminase surface expression has not been reported thus far. In this work, we produced an Arthrobacter citreus ?-transaminase in Escherichia coli using a surface display vector based on the autotransporter adhesin involved in diffuse adherence (AIDA-I), which has previously been used for display of dimeric proteins. The correct localization of the transaminase in the E. coli outer membrane and its orientation toward the cell exterior were verified. Furthermore, transaminase activity was detected exclusively in the outer membrane protein fraction, showing that successful dimerization had occurred. The transaminase was found to be present in both full-length and proteolytically degraded forms. The removal of this proteolysis is considered to be the main obstacle to achieving sufficient whole-cell transaminase activity. PMID:24487538

Gustavsson, Martin; Muraleedharan, Madhu Nair; Larsson, Gen

2014-04-01

113

Chemotaxis Toward Sugars in Escherichia coli  

PubMed Central

Using a quantitative assay for measuring chemotaxis, we tested a variety of sugars and sugar derivatives for their ability to attract Escherichia coli bacteria. The most effective attractants, i.e., those that have thresholds near 10?5 M or below, are N-acetyl-d-glucosamine, 6-deoxy-d-glucose, d-fructose, d-fucose, 1-d-glycerol-?-d-galactoside, galactitol, d-galactose, d-glucosamine, d-glucose, ?-d-glucose-1-phosphate, lactose, maltose, d-mannitol, d-mannose, methyl-?-d-galactoside, methyl-?-d-glucoside, d-ribose, d-sorbitol, and trehalose. Lactose, and probably d-glucose-1-phosphate, are attractive only after conversion to the free monosaccharide, while the other attractants do not require breakdown for taxis. Nine different chemoreceptors are involved in detecting these various attractants. They are called the N-acetyl-glucosamine, fructose, galactose, glucose, maltose, mannitol, ribose, sorbitol, and trehalose chemoreceptors; the specificity of each was studied. The chemoreceptors, with the exception of the one for d-glucose, are inducible. The galactose-binding protein serves as the recognition component of the galactose chemoreceptor. E. coli also has osmotically shockable binding activities for maltose and d-ribose, and these appear to serve as the recognition components for the corresponding chemoreceptors. PMID:4580570

Adler, Julius; Hazelbauer, Gerald L.; Dahl, M. M.

1973-01-01

114

Variation in the propensity to diversify in experimental populations of Escherichia coli: consequences  

E-print Network

displacement, diversification, Escherichia coli, growth curve analysis, metabolism, mutational bias. [UVariation in the propensity to diversify in experimental populations of Escherichia coli-switcher genotypes (reflecting different specialized metabolic phenotypes) derived from the bacterium Escherichia

Doebeli, Michael

115

Pathogenic Escherichia coli strain discrimination using laser-induced breakdown spectroscopy  

E-print Network

Pathogenic Escherichia coli strain discrimination using laser-induced breakdown spectroscopy A pathogenic strain of bacteria, Escherichia coli O157:H7 enterohemorrhagic E. coli or EHEC , has been analyzed with both nanosecond and femtosecond laser pulses to identify the Escherichia coli bacterium.10­12 E. coli

Rehse, Steven J.

116

Escherichia coli cyclopropane fatty acid synthase.  

PubMed

Escherichia coli fatty acid cyclopropane synthase (CFAS) was overproduced and purified as a His6-tagged protein. This recombinant enzyme is as active as the native enzyme with a Km of 90 microm for S-AdoMet and a specific activity of 5 x 10(-2) micromol.min(-1).mg(-1). The enzyme is devoid of organic or metal cofactors and is unable to catalyze the wash-out of the methyl protons of S-AdoMet to the solvent, data that do not support the ylide mechanism. Inactivation of the enzyme by 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB), a pseudo first-order process with a rate constant of 1.2 m(-1).s(-1), is not protected by substrates. Graphical analysis of the inactivation by DTNB revealed that only one cysteine is responsible for the inactivation of the enzyme. The three strictly conserved Cys residues among cyclopropane synthases, C139, C176 and C354 of the E. coli enzyme, were mutated to serine. The relative catalytic efficiency of the mutants were 16% for C139S, 150% for C176S and 63% for C354S. The three mutants were inactivated by DTNB at a rate comparable to the rate of inactivation of the His6-tagged wild-type enzyme, indicating that the Cys responsible for the loss of activity is not one of the conserved residues. Therefore, none of the conserved Cys residues is essential for catalysis and cannot be involved in covalent catalysis or general base catalysis. The inactivation is probably the result of steric hindrance, a phenomenon irrelevant to catalysis. It is very likely that E. coli CFAS operates via a carbocation mechanism, but the base and nucleophile remain to be identified. PMID:15606764

Courtois, Fabienne; Guérard, Christine; Thomas, Xavier; Ploux, Olivier

2004-12-01

117

Y-family DNA polymerases in Escherichia coli  

E-print Network

The observation that mutations in the Escherichia coli genes umuC+ and umuD+ abolish mutagenesis induced by UV light strongly supported the counterintuitive notion that such mutagenesis is an active rather than passive ...

Jarosz, Daniel F.

118

TRIMETHOPRIM-SULFAMETHOXAZOLE RESISTANCE IN SEWAGE ISOLATES OF ESCHERICHIA COLI  

EPA Science Inventory

Sewage samples from seven locations in the United States were analyzed for Escherichia coli isolates which were resistant to trimethoprim-sulfamethoxazole (SXT). The prevalence rate of SXT resistant organisms varied between the different geographical locales. The majority of th...

119

Serogroups of Escherichia coli from Drinking Water  

Microsoft Academic Search

Fifty seven isolates of thermotolerant E. coli were recovered from 188 drinking water sources, 45 (78.9%) were typable of which 15 (26.3%) were pathogenic serotypes. Pathogenic\\u000a serogroup obtained were 04 (Uropathogenic E. coli, UPEC), 025 (Enterotoxigenic E. coli, ETEC), 086 (Enteropathogenic E. coli, EPEC), 0103 (Shiga-toxin producing E. coli, STEC), 0157 (Shiga-toxin producing E. coli, STEC), 08 (Enterotoxigenic E. coli,

P. W. Ramteke; Suman Tewari

2007-01-01

120

The N-degradome of Escherichia coli  

PubMed Central

The N-end rule is a conserved mechanism found in Gram-negative bacteria and eukaryotes for marking proteins to be degraded by ATP-dependent proteases. Specific N-terminal amino acids (N-degrons) are sufficient to target a protein to the degradation machinery. In Escherichia coli, the adaptor ClpS binds an N-degron and delivers the protein to ClpAP for degradation. As ClpS recognizes N-terminal Phe, Trp, Tyr, and Leu, which are not found at the N terminus of proteins translated and processed by the canonical pathway, proteins must be post-translationally modified to expose an N-degron. One modification is catalyzed by Aat, an enzyme that adds leucine or phenylalanine to proteins with N-terminal lysine or arginine; however, such proteins are also not generated by the canonical protein synthesis pathway. Thus, the mechanisms producing N-degrons in proteins and the frequency of their occurrence largely remain a mystery. To address these issues, we used a ClpS affinity column to isolate interacting proteins from E. coli cell lysates under non-denaturing conditions. We identified more than 100 proteins that differentially bound to a column charged with wild-type ClpS and eluted with a peptide bearing an N-degron. Thirty-two of 37 determined N-terminal peptides had N-degrons. Most of the proteins were N-terminally truncated by endoproteases or exopeptidases, and many were further modified by Aat. The identities of the proteins point to possible physiological roles for the N-end rule in cell division, translation, transcription, and DNA replication and reveal widespread proteolytic processing of cellular proteins to generate N-end rule substrates. PMID:23960079

Humbard, Matthew A.; Surkov, Serhiy; De Donatis, Gian Marco; Jenkins, Lisa M.; Maurizi, Michael R.

2013-01-01

121

The Escherichia coli peripheral inner membrane proteome.  

PubMed

Biological membranes are essential for cell viability. Their functional characteristics strongly depend on their protein content, which consists of transmembrane (integral) and peripherally associated membrane proteins. Both integral and peripheral inner membrane proteins mediate a plethora of biological processes. Whereas transmembrane proteins have characteristic hydrophobic stretches and can be predicted using bioinformatics approaches, peripheral inner membrane proteins are hydrophilic, exist in equilibria with soluble pools, and carry no discernible membrane targeting signals. We experimentally determined the cytoplasmic peripheral inner membrane proteome of the model organism Escherichia coli using a multidisciplinary approach. Initially, we extensively re-annotated the theoretical proteome regarding subcellular localization using literature searches, manual curation, and multi-combinatorial bioinformatics searches of the available databases. Next we used sequential biochemical fractionations coupled to direct identification of individual proteins and protein complexes using high resolution mass spectrometry. We determined that the proposed cytoplasmic peripheral inner membrane proteome occupies a previously unsuspected ?19% of the basic E. coli BL21(DE3) proteome, and the detected peripheral inner membrane proteome occupies ?25% of the estimated expressed proteome of this cell grown in LB medium to mid-log phase. This value might increase when fleeting interactions, not studied here, are taken into account. Several proteins previously regarded as exclusively cytoplasmic bind membranes avidly. Many of these proteins are organized in functional or/and structural oligomeric complexes that bind to the membrane with multiple interactions. Identified proteins cover the full spectrum of biological activities, and more than half of them are essential. Our data suggest that the cytoplasmic proteome displays remarkably dynamic and extensive communication with biological membrane surfaces that we are only beginning to decipher. PMID:23230279

Papanastasiou, Malvina; Orfanoudaki, Georgia; Koukaki, Marina; Kountourakis, Nikos; Sardis, Marios Frantzeskos; Aivaliotis, Michalis; Karamanou, Spyridoula; Economou, Anastassios

2013-03-01

122

[Host factors in the regulation of the Vibrio fischeri lux operon in Escherichia coli cells].  

PubMed

It has been shown that the chaperonin GroEL, together with GroES co-chaperonin and Lon ATP-dependent protease are involved in the regulation of expression of the Vibrio fischeri lux operon in Escherichia coli cells. The cells of E. coli groE (pF1)- bearing a plasmid with the complete V. fischeri lux regulon were weakly luminescent. The cells of E. coli lonA (pF1) displayed intense bioluminescence. The same effects also occurred in mutant E. coli strains bearing a hybrid plasmid pVFR1, where the luxR gene and the regulatory region of the V. fischeri lux operon were inserted before the Photorhabdus luminescens luxCDABE cassette. The V. fischeri luxR gene was cloned in the pGEX-KG vector with the formation of a hybrid gene gst-luxR. It was shown that affinity chromatography of the product of expression, the chimeric protein GST-LuxR, on a column with glutathione-agarose resulted in its copurification with the proteins GroEL and Lon. Consequently, LuxR, the transcription activator of the lux operon, forms complexes with these proteins. It is supposed that GroEL/GroES is responsible for the folding of the LuxR protein, and Lon protease degrades the LuxR protein either before its folding into an active globule or at denaturing. PMID:17025179

Manukhov, I V; Kotova, V Iu; Zavil'gel'ski?, G B

2006-01-01

123

Phylogenetic and genomic diversity of human bacteremic Escherichia coli strains  

Microsoft Academic Search

BACKGROUND: Extraintestinal pathogenic Escherichia coli (ExPEC) strains represent a huge public health burden. Knowledge of their clonal diversity and of the association of clones with genomic content and clinical features is a prerequisite to recognize strains with a high invasive potential. In order to provide an unbiased view of the diversity of E. coli strains responsible for bacteremia, we studied

Françoise Jaureguy; Luce Landraud; Virginie Passet; Laure Diancourt; Eric Frapy; Ghislaine Guigon; Etienne Carbonnelle; Olivier Lortholary; Olivier Clermont; Erick Denamur; Bertrand Picard; Xavier Nassif; Sylvain Brisse

2008-01-01

124

Integrated Genomic Map from Uropathogenic Escherichia coli J96  

Microsoft Academic Search

Escherichia coli J96 is a uropathogen having both broad similarities to and striking differences from nonpathogenic, laboratory E. coli K-12. Strain J96 contains three large (>100-kb) unique genomic segments integrated on the chromosome; two are recognized as pathogenicity islands containing urovirulence genes. Additionally, the strain possesses a fourth smaller accessory segment of 28 kb and two deletions relative to strain

LYLA J. MELKERSON-WATSON; CHRISTOPHER K. RODE; LIXIN ZHANG; BETSY FOXMAN; CRAIG A. BLOCH

2000-01-01

125

Escherichia coli Response to Exogenous Pyrophosphate and Analogs  

Microsoft Academic Search

The addition of exogenous pyrophosphate increases the growth yield and cAMP synthesis in stationary phase when Escherichia coli is grown in minimal medium. Pyrophosphate increases the yield by altering the enterobactin uptake system. We studied the physiological effects and examined how the E. coli transcriptome was modified when two structural analogs of pyrophosphate were added to the growth medium. Methylenediphosphonic

Francis Biville; Taku Oshima; Hirotada Mori; Yuya Kawagoe; Odile Bouvet; Marie-Noëlle Rager; Marina Perrotte-Piquemal; Antoine Danchin

2003-01-01

126

Genetic engineering of ethanol production in Escherichia coli  

Microsoft Academic Search

The genes encoding essential enzymes of the fermentative pathway for ethanol production in Zymomonas mobilis, an obligately ethanologenic bacterium, were inserted into Escherichia coli under the control of a common promoter. Alcohol dehydrogenase II and pyruvate decarboxylase from Z. mobilis were expressed at high levels in E. coli, resulting in increased cell growth and the production of ethanol as the

L. O. Ingram; T. Conway; D. P. Clark; G. W. Sewell; J. F. Preston

1987-01-01

127

Complete Genome Sequence of Escherichia coli BW25113.  

PubMed

Escherichia coli BW25113 is the parent strain of the Keio collection comprising nearly 4,000 single-gene deletion mutants. We report the complete 4,631,469-bp genome sequence of this strain and the key variations from the type strain E. coli MG1655. PMID:25323716

Grenier, Frédéric; Matteau, Dominick; Baby, Vincent; Rodrigue, Sébastien

2014-01-01

128

Transcriptional effects of CRP* expression in Escherichia coli  

Microsoft Academic Search

BACKGROUND: Escherichia coli exhibits diauxic growth in sugar mixtures due to CRP-mediated catabolite repression and inducer exclusion related to phosphotransferase system enzyme activity. Replacement of the native crp gene with a catabolite repression mutant (referred to as crp*) enables co-utilization of glucose and other sugars in E. coli. While previous studies have examined the effects of expressing CRP* mutants on

Reza Khankal; Jonathan W Chin; Debashis Ghosh; Patrick C Cirino

2009-01-01

129

Complete Genome Sequence of Escherichia coli BW25113  

PubMed Central

Escherichia coli BW25113 is the parent strain of the Keio collection comprising nearly 4,000 single-gene deletion mutants. We report the complete 4,631,469-bp genome sequence of this strain and the key variations from the type strain E. coli MG1655. PMID:25323716

Grenier, Frederic; Matteau, Dominick; Baby, Vincent

2014-01-01

130

Transformation of Escherichia coli by a specific DNA restriction fragment  

Microsoft Academic Search

Specific transformation of a rifampicin sensitive strain of Escherichia coli to rifampicin resistance has been performed by a single, defined DNA restriction fragment carrying the genetic information for the ß subunit of E. coli RNA polymerase. In this transformation the transforming genetic character has been substituted for the corresponding recipient gene locus by recombination. The value of the described transformation

Silvia M. Schweitzer; Hans Matzura

1977-01-01

131

Instability of repeated DNAs during transformation in Escherichia coli  

Microsoft Academic Search

Escherichia coli has provided an important model system for understanding the molecular basis for genetic instabilities associated with repeated DNA. Changes in triplet repeat length during growth following transformation in E. coli have been used as a measure of repeat instability. However, very little is known about the molecular and biological changes that may occur on transformation. Since only a

Vera I. Hashem; Elzbieta A. Klysik; William A. Rosche; Richard R. Sinden

2002-01-01

132

Motility and Chemotaxis of Filamentous Cells of Escherichia coli  

Microsoft Academic Search

Filamentous cells of Escherichia coli can be produced by treatment with the antibiotic cephalexin, which blocks cell division but allows cell growth. To explore the effect of cell size on chemotactic activity, we studied the motility and chemotaxis of filamentous cells. The filaments, up to 50 times the length of normal E. coli organisms, were motile and had flagella along

NAZLI MAKI; JASON E. GESTWICKI; ELLEN M. LAKE; LAURA L. KIESSLING; J. Adler

2000-01-01

133

Biocontrol of Escherichia coli O157  

PubMed Central

The effect of a bacteriophage cocktail (EcoShield™) that is specific against Escherichia coli O157:H7 was evaluated against a nalidixic acid-resistant enterohemorrhagic E. coli O157:H7 RM4407 (EHEC) strain on leafy greens stored under either (1) ambient air or (2) modified atmosphere (MA; 5% O2/35% CO2/60% N2). Pieces (~2 × 2 cm2) of leafy greens (lettuce and spinach) inoculated with 4.5 log CFU/cm2 EHEC were sprayed with EcoShield™ (6.5 log PFU/cm2). Samples were stored at 4 or 10°C for up to 15 d. On spinach, the level of EHEC declined by 2.38 and 2.49 log CFU/cm2 at 4 and 10°C, respectively, 30 min after phage application (p ? 0.05). EcoShield™ was also effective in reducing EHEC on the surface of green leaf lettuce stored at 4°C by 2.49 and 3.28 log units in 30 min and 2 h, respectively (p ? 0.05). At 4°C under atmospheric air, the phage cocktail significantly (p ? 0.05) lowered the EHEC counts in one day by 1.19, 3.21 and 3.25 log CFU/cm2 on spinach, green leaf and romaine lettuce, respectively compared with control (no bacteriophage) treatments. When stored under MA at 4°C, phages reduced (p ? 0.05) EHEC populations by 2.18, 3.50 and 3.13 log CFU/cm2, on spinach, green leaf and romaine lettuce. At 10°C, EHEC reductions under atmospheric air storage were 1.99, 3.90 and 3.99 log CFU/cm2 (p ? 0.05), while population reductions under MA were 3.08, 3.89 and 4.34 logs on spinach, green leaf and romaine lettuce, respectively, compared with controls (p ? 0.05). The results of this study showed that bacteriophages were effective in reducing the levels of E. coli O157:H7 on fresh leafy produce, and that the reduction was further improved when produce was stored under the MA conditions. PMID:23819107

Boyacioglu, Olcay; Sharma, Manan; Sulakvelidze, Alexander; Goktepe, Ipek

2013-01-01

134

Escherichia coli pathotypes occupy distinct niches in the mouse intestine.  

PubMed

Since the first step of the infection process is colonization of the host, it is important to understand how Escherichia coli pathogens successfully colonize the intestine. We previously showed that enterohemorrhagic O157:H7 strain E. coli EDL933 colonizes a niche in the streptomycin-treated mouse intestine that is distinct from that of human commensal strains, which explains how E. coli EDL933 overcomes colonization resistance imparted by some, but not all, commensal E. coli strains. Here we sought to determine if other E. coli pathogens use a similar strategy. We found that uropathogenic E. coli CFT073 and enteropathogenic E. coli E2348/69 occupy intestinal niches that are distinct from that of E. coli EDL933. In contrast, two enterohemorrhagic strains, E. coli EDL933 and E. coli Sakai, occupy the same niche, suggesting that strategies to prevent colonization by a given pathotype should be effective against other strains of the same pathotype. However, we found that a combination of commensal E. coli strains that can prevent colonization by E. coli EDL933 did not prevent colonization by E. coli CFT073 or E. coli E2348/69. Our results indicate that development of probiotics to target multiple E. coli pathotypes will be problematic, as the factors that govern niche occupation and hence stable colonization vary significantly among strains. PMID:24566621

Meador, Jessica P; Caldwell, Matthew E; Cohen, Paul S; Conway, Tyrrell

2014-05-01

135

Shiga toxin-producing Escherichia coli  

PubMed Central

Shiga toxin-producing Escherichia coli (STEC) cause hemorrhagic colitis (HC) and hemolytic uremic syndrome (HUS) in humans. Outbreaks are linked to bovine food sources. STEC O157:H7 has been responsible for the most severe outbreaks worldwide. However, non-O157 serotypes have emerged as important enteric pathogens in several countries. The main virulence factor of STEC is the production of Shiga toxins 1 and 2. Additional virulence markers are a plasmid-encoded enterohemolysin (ehxA), an autoagglutinating adhesin (Saa), a catalase-peroxidase (katP), an extracellular serine protease (espP), a zinc metalloprotease (stcE), a subtilase cytotoxin (subAB), among others. Other virulence factors are intimin and adhesins that had a roll in the adherence of STEC to bovine colon. This review focuses on the virulence traits of STEC and especially on those related to the adhesion to bovine colon. The known of the interaction between STEC and the bovine host is crucial to develop strategies to control cattle colonization. PMID:23624795

Etcheverria, Analia Ines; Padola, Nora Lia

2013-01-01

136

Oligosaccharide Binding in Escherichia coli Glycogen Synthase  

SciTech Connect

Glycogen/starch synthase elongates glucan chains and is the key enzyme in the synthesis of glycogen in bacteria and starch in plants. Cocrystallization of Escherichia coli wild-type glycogen synthase (GS) with substrate ADPGlc and the glucan acceptor mimic HEPPSO produced a closed form of GS and suggests that domain-domain closure accompanies glycogen synthesis. Cocrystallization of the inactive GS mutant E377A with substrate ADPGlc and oligosaccharide results in the first oligosaccharide-bound glycogen synthase structure. Four bound oligosaccharides are observed, one in the interdomain cleft (G6a) and three on the N-terminal domain surface (G6b, G6c, and G6d). Extending from the center of the enzyme to the interdomain cleft opening, G6a mostly interacts with the highly conserved N-terminal domain residues lining the cleft of GS. The surface-bound oligosaccharides G6c and G6d have less interaction with enzyme and exhibit a more curled, helixlike structural arrangement. The observation that oligosaccharides bind only to the N-terminal domain of GS suggests that glycogen in vivo probably binds to only one side of the enzyme to ensure unencumbered interdomain movement, which is required for efficient, continuous glucan-chain synthesis.

Sheng, Fang; Yep, Alejandra; Feng, Lei; Preiss, Jack; Geiger, James H.; (MSU)

2010-11-17

137

The DNA exonucleases of Escherichia coli  

PubMed Central

DNA exonucleases, enzymes that hydrolyze phosphodiester bonds in DNA from a free end, play important cellular roles in DNA repair, genetic recombination and mutation avoidance in all organisms. This article reviews the structure, biochemistry and biological functions of the 17 exonucleases currently identified in the bacterium Escherichia coli. These include the exonucleases associated with DNA polymerases I (polA), II (polB) and III (dnaQ/mutD), Exonucleases I (xonA/sbcB), III (xthA), IV, VII (xseAB), IX (xni/xgdG) and X (exoX), the RecBCD, RecJ, and RecE exonucleases, SbcCD endo/exonuclease, the DNA exonuclease activities of RNase T (rnt) and Endonuclease IV (nfo) and TatD. These enzymes are diverse in terms of substrate specificity and biochemical properties and have specialized biological roles. Most of these enzymes fall into structural families with characteristic sequence motifs, and members of many of these families can be found in all domains of life.

Lovett, Susan T.

2014-01-01

138

Regulation of the Escherichia coli lrp gene.  

PubMed Central

Lrp (leucine-responsive regulatory protein) is a major Escherichia coli regulatory protein which regulates expression of a number of operons, some negatively and some positively. This work relates to a characterization of lrp, the gene encoding Lrp. Nucleotide sequencing established that the coding regions of lrp and trxB (encoding thioredoxin reductase) are separated by 543 bp and that the two genes are transcribed in opposite directions. In addition, we used primer extension, deletion analyses, and lrp-lacZ transcriptional fusions to delineate the promoter and regulatory region of the lrp operon. The lrp promoter is located 267 nucleotides upstream of the translational start codon of the lrp gene. In comparison with a wild-type strain, expression of the lrp operon was increased about 3-fold in a strain lacking Lrp and decreased about 10-fold in a strain overproducing Lrp. As observed from DNA mobility shift and DNase I footprinting analyses, Lrp binds to one or more sites within the region -80 to -32 relative to the start point of lrp transcription. A mutational analysis indicated that this same region is at least partly required for repression of lrp expression in vivo. These results demonstrate that autogenous regulation of lrp involves Lrp acting directly to cause repression of lrp transcription. Images PMID:8144448

Wang, Q; Wu, J; Friedberg, D; Plakto, J; Calvo, J M

1994-01-01

139

EcoCyc: A comprehensive view of Escherichia coli biology  

Microsoft Academic Search

EcoCyc (http:\\/\\/EcoCyc.org) provides a comprehen- sive encyclopedia of Escherichia coli biology. EcoCyc integrates information about the genome, genes and gene products; the metabolic network; and the regulatory network of E. coli. Recent EcoCyc developments include a new initiative to represent and curate all types of E. coli regulatory processes such as attenuation and regulation by small RNAs. EcoCyc has started

Ingrid M. Keseler; César Bonavides-martínez; Julio Collado-vides; Socorro Gama-castro; Robert P. Gunsalus; D. Aaron Johnson; Markus Krummenacker; Laura M. Nolan; Suzanne M. Paley; Ian T. Paulsen; Martín Peralta-gil; Alberto D. Santos-zavaleta; Alexander Glennon Shearer; Peter D. Karp

2009-01-01

140

Detection of Escherichia coli in wastewater based on enzyme immunoassay  

Microsoft Academic Search

This research describes a fast detection method on the basis of enzyme-linked immunosorbent assay (ELISA) for Escherichia coli in drainage of wastewater treatment plants. Optimized conditions such as the reaction format (sandwich or direct), the concentrations\\u000a of diluted horseradish peroxidase (HRP)-E. coli conjugate, and anti-HPR antibody and pretreatment of E. coli were studied. Those results showed that the linear range

Haiyan Xi; Qiang Cai; Miao He; Hanchang Shi

2007-01-01

141

Functional Homology of Chemotaxis Genes Escherichia coli and Salmonella typhimurium  

Microsoft Academic Search

Generally nonchemotactic mutants of Escherichia coli and Salmonella typhi- murium were analyzed by interspecies complementation tests to determine the functional correspondence between the che genes of these two organisms. The E. coli che region was introduced into Salnonella recipients by means of a series of F-prime elements. Wild-type che genes of E. coli F'420 complemented all che mutants of Sabnonella

Anthony L. Defranco; JOHN S. PARKINSON; D. E. KOSHLAND

1979-01-01

142

Involvement of Escherichia coli DNA polymerase IV in tolerance of cytotoxic alkylating DNA lesions in vivo  

E-print Network

1 Involvement of Escherichia coli DNA polymerase IV in tolerance of cytotoxic alkylating DNA coli DNA polymerase IV Key words: Escherichia coli, dinB, alkylation damage, DNA repair Corresponding Escherichia coli PolIV, a DNA polymerase capable to catalyze synthesis past replication- blocking DNA lesions

143

Evolution of transcription factors and the gene regulatory network in Escherichia coli  

E-print Network

Evolution of transcription factors and the gene regulatory network in Escherichia coli M. Madan Escherichia coli. In order to gain insight into the evolution of the E.coli regula- tory network, we analysed-dimensional structures. Theoretical analyses of transcription factors in Escherichia coli have focused on their sequence

Babu, M. Madan

144

Enteropathogenic Escherichia coli translocated intimin receptor, Tir, requires a specic chaperone for stable  

E-print Network

Enteropathogenic Escherichia coli translocated intimin receptor, Tir, requires a speci®c chaperone. Summary Enteropathogenic Escherichia coli (EPEC) secretes several Esps (E. coli-secreted proteins Enteropathogenic Escherichia coli (EPEC) is a major cause of diarrhoea in young children (Donnenberg and Kaper

Strynadka, Natalie

145

????????????? ?????? ???????? ???????????? ?-?????????? SHV-????? ?? ??????? ??????? ??? ????? Klebsiella pneumoniae, Escherichia coli ??? Serratia marcescens.: [???] ???????? ?. ?????????.  

E-print Network

?????????????? ? ?????????? ??? ????????? ????????????? ??? ???? ???????????? ?-?????????? SHV-?????.? SHV-9 ?-????????? ??????????? ??? ??????? ??????? ?.PNEUMONIAE,E.COLI KAI S.MARCESCENS.ME ????? ???????? ????????? ???????.?? ?????… (more)

??????????, ????????

1997-01-01

146

A bioluminescence-based assay for enumeration of lytic bacteriophage.  

PubMed

A bioluminescence-based assay for enumeration of lytic bacteriophage was developed. The assay consists of a bioluminescent Escherichia coli as the host bacterium, the lytic bacteriophage T4 and an automated luminometer measuring luminescence over time. The assay is based on the decrease in luminescence as the bioluminescent host cells are lysed by T4. The T4 concentration, bioluminescent E. coli concentration, phage suspension medium, and temperature (25 degrees C and 37 degrees C) were varied. There was a strong negative correlation between bioluminescence intensities and T4 phage concentrations at both room temperature (R(2)=0.993) and 37 degrees C (R(2)=0.970). Phage was detected more rapidly at 37 degrees C than at 25 degrees C. The detection limit was also lower when the assay was performed at 37 degrees C with a minimum detection level of 2.4 log CFU/ml compared to 3.4 log CFU/ml for 25 degrees C. The assay was used to determine thermal inactivation using T4 phages heated at 70 degrees C for 0 to 30 min, and phage concentrations were determined using the bioluminescence assay and a standard plaque assay. There was no significant difference between the two enumeration methods (P>0.01). This study suggests the bioluminescence-based assay can be used as an alternative for quantitatively monitoring phage infectivity, instead of conventional standard plaque assays. PMID:19628012

Kim, S; Schuler, B; Terekhov, A; Auer, J; Mauer, L J; Perry, L; Applegate, B

2009-10-01

147

Tobramycin uptake in Escherichia coli membrane vesicles.  

PubMed Central

The uptake of tobramycin was measured in Escherichia coli membrane vesicles prepared in KMES [K(+)-2-(N-morpholino)ethanesulfonic acid] buffer at pH 6.6. Uptake occurred in vesicles energized with ascorbic acid and phenazine methosulfate, in which the electrical potential (delta psi) was -120 mV, but not in vesicles energized with D-lactate (delta psi = -95 mV). The addition of nigericin to vesicles energized with D-lactate did not induce tobramycin uptake despite an increase in delta psi to -110 mV. However, when delta psi was increased or decreased by the addition of nigericin or valinomycin, respectively, uptake in vesicles energized with ascorbic acid and phenazine methosulfate was stimulated or inhibited, respectively, confirming studies with whole cells showing that uptake of aminoglycosides is gated by delta psi rather than by proton motive force (delta microH+) or delta pH. N-ethylmaleimide prevented uptake, suggesting that the aminoglycoside transporter is a cytoplasmic membrane protein with accessible sulfhydryl groups. The observation that uptake is gated in vesicles as well as in whole cells suggested that diffusion occurs through a voltage-gated channel. In vesicles preloaded with tobramycin, no efflux occurred after the addition of the protonophore carbonyl cyanide m-chlorophenylhydrazone. In susceptible cells, aminoglycosides themselves decreased the magnitude of delta psi. We propose a mechanism of aminoglycoside-induced killing in which aminoglycosides themselves close the voltage-gated channel by decreasing the magnitude of delta psi. Channel closure causes aminoglycosides accumulated prior to the fall in delta psi to be trapped, which in turn causes irreversible uptake and subsequent bactericidal effects. PMID:7726517

Leviton, I M; Fraimow, H S; Carrasco, N; Dougherty, T J; Miller, M H

1995-01-01

148

Dissemination and Systemic Colonization of Uropathogenic Escherichia coli in a Murine Model of Bacteremia  

PubMed Central

Infection with uropathogenic Escherichia coli (UPEC), the causative agent of most uncomplicated urinary tract infections, proceeds in an ascending manner and, if left untreated, may result in bacteremia and urosepsis. To examine the fate of UPEC after its entry into the bloodstream, we developed a murine model of sublethal bacteremia. CBA/J mice were inoculated intravenously with 1 × 106 CFU of pyelonephritis strain E. coli CFT073 carrying a bioluminescent reporter. Biophotonic imaging, used to monitor the infection over 48 h, demonstrated that the bacteria disseminated systemically and appeared to localize at discrete sites. UPEC was recovered from the spleen, liver, kidneys, lungs, heart, brain, and intestines as early as 20 min postinoculation, peaking at 24 h postinoculation. A nonpathogenic E. coli K-12 strain, however, disseminated at significantly lower levels (P < 0.01) and was cleared from the liver and cecum by 24 h postinoculation. Isogenic mutants lacking type 1 fimbriae, P fimbriae, capsule, TonB, the heme receptors Hma and ChuA, or particularly the sialic acid catabolism enzyme NanA were significantly outcompeted by wild-type CFT073 during bacteremia (P < 0.05), while flagellin and hemolysin mutants were not. PMID:21116344

Smith, Sara N.; Hagan, Erin C.; Lane, M. Chelsea; Mobley, Harry L. T.

2010-01-01

149

Serological cross-reactions between Escherichia coli O157 and other species of the genus Escherichia.  

PubMed

The antigenic relatedness of Escherichia coli O157 and four sorbitol-negative species of the genus Escherichia was examined. Isolates of Escherichia hermannii, E. fergusonii, E. vulneris, and E. blattae were tested in the tube agglutination assay by using polyclonal antisera and in the slide agglutination assay by using latex reagents. Only four isolates (17%) of E. hermannii exhibited serological cross-reactivity. PMID:1583138

Rice, E W; Sowers, E G; Johnson, C H; Dunnigan, M E; Strockbine, N A; Edberg, S C

1992-05-01

150

Evolution of Escherichia coli rifampicin resistance in an antibiotic-free environment during thermal stress  

E-print Network

antibiotic resistance and the population genetics of adaptive evolutionEvolution of Escherichia coli rifampicin resistance in an antibiotic-Evolution of Escherichia coli rifampicin resistance in an antibiotic-

Rodríguez-Verdugo, Alejandra; Gaut, Brandon S; Tenaillon, Olivier

2013-01-01

151

The Evolution and Structural Anatomy of the Small Molecule Metabolic Pathways in Escherichia coli  

E-print Network

The Evolution and Structural Anatomy of the Small Molecule Metabolic Pathways in Escherichia coli The 106 small molecule metabolic (SMM) pathways in Escherichia coli are formed by the protein products

Gough, Julian

152

Infection by verocytotoxin-producing Escherichia coli.  

PubMed Central

Verocytotoxin (VT)-producing Escherichia coli (VTEC) are a newly recognized group of enteric pathogens which are increasingly being recognized as common causes of diarrhea in some geographic settings. Outbreak studies indicate that most patients with VTEC infection develop mild uncomplicated diarrhea. However, a significant risk of two serious and potentially life-threatening complications, hemorrhagic colitis and the hemolytic uremic syndrome, makes VTEC infection a public health problem of serious concern. The main reservoirs of VTEC appear to be the intestinal tracts of animals, and foods of animal (especially bovine) origin are probably the principal sources for human infection. The term VT refers to a family of subunit exotoxins with high biological activity. Individual VTEC strains elaborate one or both of at least two serologically distinct, bacteriophage-mediated VTs (VT1 and VT2) which are closely related to Shiga toxin and are thus also referred to as Shiga-like toxins. The holotoxins bind to cells, via their B subunits, to a specific receptor which is probably the glycolipid, globotriosyl ceramide (Gb3). Binding is followed by internalization of the A subunit, which, after it is proteolytically nicked and reduced to the A1 fragment, inhibits protein synthesis in mammalian cells by inactivating 60S ribosomal subunits through selective structural modification of 28S ribosomal ribonucleic acid. The mechanism of VTEC diarrhea is still controversial, and the relative roles of locally acting VT and "attaching and effacing adherence" of VTEC to the mucosa have yet to be resolved. There is increasing evidence that hemolytic uremic syndrome and possibly hemorrhagic colitis result from the systemic action of VT on vascular endothelial cells. The role of antitoxic immunity in preventing the systemic complications of VTEC infection is being explored. Antibiotics appear to be contraindicated in the treatment of VTEC infection. The most common VTEC serotype associated with human disease is O157:H7, but over 50 different VT-positive O:H serotypes have now been identified. The best strategies for diagnosing human VTEC infection include testing for the presence of free VT in fecal filtrates and examining fecal cultures for VTEC by means of deoxyribonucleic acid probes that specify genes encoding VT1 and VT2. Both methods are currently confined to specialized laboratories and await commercial development for wider use. In the meantime, most laboratories should continue to screen for the most common human VTEC serotype, O157:H7, using a sorbitol-containing MacConkey medium. Images PMID:2644022

Karmali, M A

1989-01-01

153

Diarrheagenic Escherichia coli in Children from Costa Rica  

PubMed Central

More than 5,000 diarrheal cases per year receive medical care at the National Children's Hospital of Costa Rica, and nearly 5% of them require hospitalization. A total of 173 Escherichia coli strains isolated from children with diarrhea were characterized at the molecular, serologic, and phenotypic level. Multiplex and duplex polymerase chain reactions were used to detect the six categories of diarrheagenic E. coli. Thirty percent (n = 52) of the strains were positive, indicating a high prevalence among the pediatric population. Enteropathogenic E. coli and enteroinvasive E. coli pathotypes were the most prevalent (21% and 19%, respectively). Pathogenic strains were distributed among the four E. coli phylogenetic groups A, B1, B2, and D, with groups A and B1 the most commonly found. This study used molecular typing to evaluate the prevalence of diarrheagenic E. coli reported in Costa Rica and demonstrated the importance of these pathotypes in the pediatric population. PMID:20682870

Perez, Cristian; Gomez-Duarte, Oscar G.; Arias, Maria L.

2010-01-01

154

Sepsis caused by food-borne infection with Escherichia coli.  

PubMed

We report a case of sepsis caused by Escherichia coli (E. coli) of serotype O-143. A 78-year-old man developed symptoms of gastroenteritis after ingesting raw meat on noodles. He rapidly developed respiratory failure. Blood culture grew E. coli. The sepsis seemed to have directly spread from a food-borne infection. The development of primary sepsis after ingesting E. coli is very rare. We suspect that bacterial translocation played a major role. Serotype O-143 is recognized in enteroinvasive E. coli (EIEC) as well as in Shigella dysenteriae. The pathogen in the present case is suspected of being EIEC although the isolated E. coli strain was negative for the inv and ipa genes. PMID:16415557

Wachi, Keiko; Tateda, Kazuhiro; Yamashiro, Yoshihiro; Takahashi, Miki; Matsumoto, Tetsuya; Furuya, Nobuhiko; Ishii, Yoshikazu; Akasaka, Yoshikiyo; Yamaguchi, Keizo; Uchida, Kou

2005-12-01

155

Cattle Water Troughs as Reservoirs of Escherichia coli O157  

PubMed Central

Environmental survival of Escherichia coli O157 may play an important role in the persistence and dissemination of this organism on farms. The survival of culturable and infectious E. coli O157 was studied using microcosms simulating cattle water troughs. Culturable E. coli O157 survived for at least 245 days in the microcosm sediments. Furthermore, E. coli O157 strains surviving more than 6 months in contaminated microcosms were infectious to a group of 10-week-old calves. Fecal excretion of E. coli O157 by these calves persisted for 87 days after challenge. Water trough sediments contaminated with feces from cattle excreting E. coli O157 may serve as a long-term reservoir of this organism on farms and a source of infection for cattle. PMID:11425721

LeJeune, Jeffrey T.; Besser, Thomas E.; Hancock, Dale D.

2001-01-01

156

Instability of Pathogenicity Islands in Uropathogenic Escherichia coli 536  

Microsoft Academic Search

The uropathogenic Escherichia coli strain 536 carries at least five genetic elements on its chromosome that meet all criteria characteristic of pathogenicity islands (PAIs). One main feature of these distinct DNA regions is their instability. We applied the so-called island-probing approach and individually labeled all five PAIs of E. coli 536 with the counterselectable marker sacB to evaluate the frequency

Barbara Middendorf; Bianca Hochhut; Kristina Leipold; Ulrich Dobrindt; Gabriele Blum-Oehler; Jorg Hacker

2004-01-01

157

In vitro antibacterial effect of yogurt on Escherichia coli  

Microsoft Academic Search

We investigated the bactericidal and bacteriostatic effects of yogurt on three strains ofEscherichia coli: human toxigenic (078:H11), rabbit pathogenic (RDEC-1) and rabbit nonpathogenic [015:K14(L):H4]. Approximately 106 organisms were incubated in yogurt, milk, broth, and modifications of these materials. Aliquots were removed at various intervals and plated on MacConkey's agar for enumeration ofE. coli. Yogurt was bactericidal (at least 5 log10

Catherine M. Kotz; Lance R. Peterson; Julia A. Moody; Dennis A. Savaiano; Michael D. Levitt

1990-01-01

158

The Complete Genome Sequence of Escherichia coli K-12  

Microsoft Academic Search

The 4,639,221- base pair sequence of Escherichia coli K-12 is presented. Of 4288 protein-coding genes annotated, 38 percent have no attributed function. Comparison with five other sequenced microbes reveals ubiquitous as well as narrowly distributed gene families; many families of similar genes within E. coli are also evident. The largest family of paralogous proteins contains 80 ABC transporters. The genome

Frederick R. Blattner; Guy Plunkett III; Craig A. Bloch; Nicole T. Perna; Valerie Burland; Monica Riley; Julio Collado-Vides; Jeremy D. Glasner; Christopher K. Rode; George F. Mayhew; Jason Gregor; Nelson Wayne Davis; Heather A. Kirkpatrick; Michael A. Goeden; Debra J. Rose; Bob Mau; Ying Shao

2007-01-01

159

Overproduction and purification of Lon protease from Escherichia coli  

Microsoft Academic Search

Lon protease, which plays a major role in degradation of abnormal proteins in Escherichia coli,was overproduced and efficiently purified using the maltose-binding protein (MBP) fusion vector. The MBP-Lon fusion protein was expressed in a soluble form in E. coli and purified to homogeneity by amylose resin in a single step. Lon protease was split from MBP by cleaving a fusion

S. Sonezaki; A. Kondo; T. Oba; Y. Ishii; Y. Kato; H. Nakayama

1994-01-01

160

Escherichia coli growth and plasmid copy numbers in continuous cultivations  

Microsoft Academic Search

Summary AnEscherichia coli K-12 strain harbouring either the plasmid pBR322, or the recombinant plasmid pKTH1220, a 14 kb derivative of pBR322, or no plasmid was grown in a chemostat. The cultivations were continued for 300–400 bacterial generations.E. coli hosts harbouring pBR322 or no plasmid grew in a similar way, but the growth of the host containing the big recombinant plasmid

P. Reinikainen; I. Virkajärvi

1989-01-01

161

Characterization of a Second Lysine Decarboxylase Isolated from Escherichia coli  

Microsoft Academic Search

We report here on the existence of a new gene for lysine decarboxylase in Escherichia coli K-12. The hybridization experiments with a cadA probe at low stringency showed that the homologous region of cadA was located in l Kohara phage clone 6F5 at 4.7 min on the E. coli chromosome. We cloned the 5.0-kb HindIII fragment of this phage clone

YOSHIMI KIKUCHI; HIROYUKI KOJIMA; TAKASHI TANAKA; YUMIKO TAKATSUKA; YOSHIYUKI KAMIO

1997-01-01

162

Deactivation of Escherichia coli by the plasma needle  

Microsoft Academic Search

In this paper we present a parameter study on deactivation of Escherichia coli (E. coli) by means of a non-thermal plasma (plasma needle). The plasma needle is a small-sized (1 mm) atmospheric glow sustained by radio-frequency excitation. This plasma will be used to disinfect heat-sensitive objects; one of the intended applications is in vivo deactivation of dental bacteria: destruction of

R. E. J. Sladek; E. Stoffels

2005-01-01

163

Data processing by the chemotaxis machinery of Escherichia coli  

Microsoft Academic Search

THE chemotactic behaviour of Escherichia coli provides a useful model for study of the molecular basis of a simple stimulus-response sequence1. Chemical stimuli are detected by specific receptors2 which in turn alter the rotation of the flagella3 to elicit movement towards attractants or away from repellents. About twenty types of chemoreceptors have been identified in E. coli4-6, suggesting that a

John S. Parkinson

1974-01-01

164

Actividad antimicrobiana de mieles del sudeste de la provincia de Buenos Aires frente a Escherichia coli  

Microsoft Academic Search

Antimicrobial activity of honey against Escherichia coli. This study assessed the susceptibility of Escherichia coli to the antimicrobial activity of honeys by different techniques. Honeys used were from the southeast region of Buenos Aires province. In order to evaluate antimicrobial activity against Escherichia coli ATCC 25922, solutions containing 0, 1, 5, 10, 25 and 50% (w\\/v) of honey were prepared.

M. F. FANGIO; M. O. IURLINA; R. FRITZ

2007-01-01

165

ORIGINAL ARTICLE Identification of stress-related proteins in Escherichia coli  

E-print Network

ORIGINAL ARTICLE Identification of stress-related proteins in Escherichia coli using the pollutant observed in Escherichia coli; for example, a rapid shift from low to high temperatures induces biofilm formation has also been demonstrated Keywords cis-dichloroethylene, Escherichia coli, hydrogen

Wood, Thomas K.

166

Selection Footprint in the FimH Adhesin Shows Pathoadaptive Niche Differentiation in Escherichia coli  

E-print Network

-adaptive, or pathoadaptive, mutations in the Escherichia coli gene encoding FimH--the major, mannose-sensitive adhesin protein of Escherichia coli, mutations in which are pathoadaptive for uropatho- genic E. coli clonesSelection Footprint in the FimH Adhesin Shows Pathoadaptive Niche Differentiation in Escherichia

Chattopadhyay, Sujay

167

Metabolism and evolution of Haemophilus influenzae deduced from a whole-genome comparison with Escherichia coli  

E-print Network

with Escherichia coli Roman L.Tatusov*§, Arcady R. Mushegian*§, Peer Bork, Nigel P. Brown, William S. Hayes, Mark recently reported. Approximately 75 % of the 4.7 Mb genome sequence of Escherichia coli is also available by Fleischmann et al. [1]. Approximately 75 % of the 4.7 Mb genome sequence of Escherichia coli is also available

Fernando, Chrisantha

168

Finite state abstraction of a stochastic model of the lactose regulation system of Escherichia coli  

E-print Network

Finite state abstraction of a stochastic model of the lactose regulation system of Escherichia coli on the lactose regulation system in Escherichia coli bacteria, one of the most extensively studied examples for the lactose regulation system in the Escherichia coli bacteria. The lactose operon [8] is one of the most

Sontag, Eduardo

169

Measuring the forces involved in polyvalent adhesion of uropathogenic Escherichia coli to  

E-print Network

Measuring the forces involved in polyvalent adhesion of uropathogenic Escherichia coli to mannose from the interaction of uropathogenic Escherichia coli to molecularly well defined models of cellular, Escherichia coli [the primary causative agent of urinary tract infections (3, 4)] use the FimH adhesin located

Prentiss, Mara

170

Proteome analysis of factor for inversion stimulation (Fis) overproduction in Escherichia coli  

E-print Network

Proteome analysis of factor for inversion stimulation (Fis) overproduction in Escherichia coli The factor-for-inversion stimulation protein (Fis) is a global regulatory protein in Escherichia coli protein precursor, and ketol-acid reductoisomerase. Keywords: Proteome analysis / Fis / Escherichia coli

Chen, Wilfred

171

SLECTION ET PERSISTANCE, DANS LA FLORE FCALE DE VEAUX DE BOUCHERIE, DE ESCHERICHIA COLI  

E-print Network

S�LECTION ET PERSISTANCE, DANS LA FLORE F�CALE DE VEAUX DE BOUCHERIE, DE ESCHERICHIA COLI R�SISTANT of oxytetracycline on the resistance of fecal Escherichia coli to the following antibacterial agents: ampicillin (Ap flore fécale, de souches d'Escherichia coli résistantes à cet antibiotique (Mitsuhashi, 1979). Ces sou

Paris-Sud XI, Université de

172

Chemosensing in Escherichia coli: Two regimes of two-state receptors  

E-print Network

Chemosensing in Escherichia coli: Two regimes of two-state receptors Juan E. Keymer* , Robert G, 2005 (received for review August 26, 2005) The chemotaxis network in Escherichia coli is remarkable The chemotaxis network in Escherichia coli is the best studied signal-transduction network of any living organism

Meir, Yigal

173

Dynamic Receptor Team Formation Can Explain the High Signal Transduction Gain in Escherichia coli  

E-print Network

Dynamic Receptor Team Formation Can Explain the High Signal Transduction Gain in Escherichia coli in the peritrichous bacterium Escherichia coli, which has four helical flagella distributed over the cell surface explain this observation. INTRODUCTION Escherichia coli has five receptor types, but most is known about

Othmer, Hans

174

Escherichia coli: a brief review of diarrheagenic pathotypes and their role in diarrheal diseases in Iran  

E-print Network

Escherichia coli: a brief review of diarrheagenic pathotypes and their role in diarrheal diseases, Tehran. 2 Bacteriology Department, Pasteur Institute of Iran, Tehran. 3 National Escherichia coli, Aslani MM Address: Molecular Biology Unit, Pasteur Institute of Iran. National Escherichia coli Reference

Paris-Sud XI, Université de

175

Uncharacterized Escherichia coli proteins YdjA and YhjY are related to biohydrogen production  

E-print Network

Uncharacterized Escherichia coli proteins YdjA and YhjY are related to biohydrogen production Mohd: Biohydrogen Escherichia coli ydjA yhjY FHL inactivation a b s t r a c t Biohydrogen has gained importance and efficiency of biohydrogen production from various microorganisms and substrates. Here, Escherichia coli

Wood, Thomas K.

176

Brief Original Article Multiple contaminations of chickens with Campylobacter, Escherichia coli  

E-print Network

Brief Original Article Multiple contaminations of chickens with Campylobacter, Escherichia coli, Escherichia coli, and Salmonella are mainly caused by the consumption of raw or undercooked poultry meat. The objective of this study was to evaluate the prevalence of Campylobacter, Escherichia coli, and Salmonella

Paris-Sud XI, Université de

177

RELATEDNESS OF ESCHERICHIA COLI WITH DIFFERENT SUSCEPTIBILITY1 PHENOTYPES ISOLATED FROM SWINE FECES DURING AMPICILLIN2  

E-print Network

1 RELATEDNESS OF ESCHERICHIA COLI WITH DIFFERENT SUSCEPTIBILITY1 PHENOTYPES ISOLATED FROM SWINE. Bousquet-Mélou1* 5 6 Running title: Relatedness of fecal Escherichia coli isolates7 8 UMR181 Escherichia coli populations during treatment with ampicillin for 7 days in pigs. Before23 treatment, only 6

Boyer, Edmond

178

Finite state abstraction of a stochastic model of the lactose regulation system of Escherichia coli  

E-print Network

Finite state abstraction of a stochastic model of the lactose regulation system of Escherichia coli on the lactose regulation system in Escherichia coli bacteria, one of the most extensively studied examples hybrid model for the lactose regulation system in the Escherichia coli bacteria. The lactose operon [10

Pappas, George J.

179

Division accuracy in a stochastic model of Min oscillations in Escherichia coli  

E-print Network

Division accuracy in a stochastic model of Min oscillations in Escherichia coli Rex A. Kerr in Escherichia coli requires the Min proteins MinC, MinD, and MinE as well as the presence of nucleoids. Min, to explain wild-type accuracy. dynamics MCELL FtsZ The rod-shaped bacterium Escherichia coli reproduces

Watkins, Joseph C.

180

Unstable Escherichia coli L-forms revisited:4 growth requires peptidoglycan synthesis5  

E-print Network

1 1 2 3 Unstable Escherichia coli L-forms revisited:4 growth requires peptidoglycan synthesis5 of a wild type Escherichia coli K-12 strain overnight to a growing5 L-form-like state, using the -lactam L-forms require, using Escherichia coli K-12 as model.8 Septal synthesis is carried out

Paris-Sud XI, Université de

181

Escherichia coli heat-stable enterotoxin b (STb) in vivo internalization within rat intestinal epithelial cells  

E-print Network

Short note Escherichia coli heat-stable enterotoxin b (STb) in vivo internalization within rat distributed within the cell. Escherichia coli / STb enterotoxin / internalization Résumé ­ Internalisation in vivo de l'entérotoxine b (STb) d'Escherichia coli dans les cellules épithéliales d'intestin de rat. L

Boyer, Edmond

182

An Experimental and Theoretical Study of the Inhibition of Escherichia coli lac  

E-print Network

An Experimental and Theoretical Study of the Inhibition of Escherichia coli lac Operon Gene the inhibition of Escherichia coli lac operon gene expression by anti- gene oligos. Our model predicted 74: 220­229, 2001. Keywords: Escherichia coli lac operon; antigene oligo- nucleotide; triplex

Relue, Patricia

183

Effects of Discontinuities in the DNA Template on Abortive Initiation and Promoter Escape by Escherichia coli  

E-print Network

by Escherichia coli RNA Polymerase* Received for publication,March 22, 2007, and in revised form, July 20, 2007 related to the process of transcription initiation by Escherichia coli RNA polymerase, confirming transcribing complexes (ITCs)2 of Escherichia coli RNA polymerase bearing 5­8-nt transcripts revealed

Tullius, Thomas D.

184

Cross-reaction of chalcone synthase and stilbene synthase overexpressed in Escherichia coli  

E-print Network

Cross-reaction of chalcone synthase and stilbene synthase overexpressed in Escherichia coli Toshio STS overexpressed in Escherichia coli, bisnoryangonin (BNY, the derailed lactone after two that was overexpressed in Escherichia coli, we have detected bisnoryangonin (BNY, the derailed lactone after two

Suh, Dae-Yeon

185

Author's personal copy Improving cellular malonyl-CoA level in Escherichia coli  

E-print Network

Author's personal copy Improving cellular malonyl-CoA level in Escherichia coli via metabolic a b s t r a c t Escherichia coli only maintains a small amount of cellular malonyl-CoA, impeding its, Escherichia coli has become an attractive host for natural product manufac- ture, owing to its genetic

Zhao, Huimin

186

Review article Escherichia coli as a pathogen in dogs and cats  

E-print Network

Review article Escherichia coli as a pathogen in dogs and cats Lothar Beutin Robert Koch; accepted 17December 1998) Abstraet-Certain strains of Escherichia coli behave as pathogens in dogs and cats. © Inra/Elsevier, Paris. Escherichia coli infections / dogs / cats / humans / diarrhoea / extra

Paris-Sud XI, Université de

187

Motility of Escherichia coli cells in clusters formed by chemotactic aggregation  

E-print Network

Motility of Escherichia coli cells in clusters formed by chemotactic aggregation Nikhil Mittal of Escherichia coli under conditions of certain cellular stresses excrete attractants. Cells of chemotactic Escherichia coli and Salmonella spp., have been studied in great detail (1­3). For our purposes, the following

van Oudenaarden, Alexander

188

DNA modication and functional delivery into human cells using Escherichia coli DH10B  

E-print Network

DNA modi®cation and functional delivery into human cells using Escherichia coli DH10B Kumaran report a novel comprehen- sive Escherichia coli-based vector system for the modi®cation, propagation in recombination- de®cient Escherichia coli DH10B imparts greater stability to the large BAC clones but has made

Warburton, Peter E.

189

Reprogramming of Escherichia coli K-12 Metabolism during the Initial Phase of Transition from an Anaerobic  

E-print Network

Reprogramming of Escherichia coli K-12 Metabolism during the Initial Phase of Transition from anaerobe Escherichia coli K-12 provides an ideal system for exploring this process. Methods and Findings) Reprogramming of Escherichia coli K-12 Metabolism during the Initial Phase of Transition from an Anaerobic

Williamson, Mike P.

190

Prevalence of Escherichia coli O157:H7 and Salmonella spp. in surface waters of southern  

E-print Network

Prevalence of Escherichia coli O157:H7 and Salmonella spp. in surface waters of southern Alberta. To address these concerns, we conducted a 2-year study to estimate the prevalence of Escherichia coli O157:H7 afin d'évaluer la prévalence de Escherichia coli O157:H7 et de Salmonella spp. dans les eaux de surface

Selinger, Brent

191

In vivo Dissection of the Tat Translocation Pathway in Escherichia coli  

E-print Network

-ColV. The translocation of RR-ColV fully inhibited the growth of wild-type Escherichia coli and those of the Átat for bacteria only under certain growth conditions. Escherichia coli Tat components are encoded by the tatIn vivo Dissection of the Tat Translocation Pathway in Escherichia coli Be�rengeÁre Ize1 , Fabien

Palmer, Tracy

192

Bioaccumulation of Arsenic in recombinant Escherichia coli expressing human metallothionein  

Microsoft Academic Search

The recombinant Escherichia coli (E. coli) expressing human hepatic metallothionein_IA (hMT_IA) was constructed for bioaccumulation of Arsenic (As). The gene sequence\\u000a of hMT_IA was modified for codon preference of E. coli and synthesized using chemical method. The vector of pGEX_4T_1 was used and hMT_IA was expressed as the fusion protein with\\u000a glutathione S-transferase (GST) tag. The bioaccumulation capability of arsenite

Yu-Jie Su; Jian-Qun Lin; Jian-Qiang Lin; Dong-Hui Hao

2009-01-01

193

Analyzing the Escherichia coli Gene Expression Data by a Multilayer Adjusted Tree Organizing Map  

E-print Network

1 Analyzing the Escherichia coli Gene Expression Data by a Multilayer Adjusted Tree Organizing Map on biological data, none of them has examined the Escherichia coli (E. coli) gene expression data. This paper. coli gene expression data. In a semi-supervised manner, MATOM constructs a multilayer map

Gruenwald, Le

194

Escherichia coli producing CNF1 and CNF2 cytotoxins in animals with different disorders  

E-print Network

Short note Escherichia coli producing CNF1 and CNF2 cytotoxins in animals with different disorders probe I disorder Résumé ― Présence d'Escherichia coli productrices des cytotoxines CNF1 et CNF2 coli strains in a collection of 553 E coli isolates from cattle, sheep, goats, pigs, horses, dogs, cats

Paris-Sud XI, Université de

195

Escherichia coli K88 adhesion : A comparison of Chinese and Large White piglets  

E-print Network

Note Escherichia coli K88 adhesion : A comparison of Chinese and Large White piglets J.P. CHAPPUIS : K88 adhesion, E. coli, pig, genetic resistance. Résumé L'attachement de Escherichia coli K88, maintained in plastic film isolators. Shortly after successive oral inoculations of 2 E. coli strains, one K

Paris-Sud XI, Université de

196

Slugs: Potential Novel Vectors of Escherichia coli O157  

PubMed Central

Field and laboratory studies were performed to determine whether slugs could act as novel vectors for pathogen (e.g., Escherichia coli O157) transfer from animal feces to salad vegetables. Escherichia coli O157 was isolated from 0.21% of field slugs from an Aberdeenshire sheep farm. These isolates carried the verocytotoxin genes (vt1 and vt2) and the attaching and effacing gene (eae), suggesting that they are potentially pathogenic to humans. Strain typing using multilocus variable number tandem repeats analysis showed that slug and sheep isolates were indistinguishable. Laboratory experiments using an E. coli mutant resistant to nalidixic acid showed that the ubiquitous slug species Deroceras reticulatum could carry viable E. coli on its external surface for up to 14 days. Slugs that had been fed E. coli shed viable bacteria in their feces with numbers showing a short but statistically significant linear log decline. Further, it was found that E. coli persisted for up to 3 weeks in excreted slug feces, and hence, we conclude that slugs have the potential to act as novel vectors of E. coli O157. PMID:16391036

Sproston, Emma L.; Macrae, M.; Ogden, Iain D.; Wilson, Michael J.; Strachan, Norval J. C.

2006-01-01

197

Slugs: potential novel vectors of Escherichia coli O157.  

PubMed

Field and laboratory studies were performed to determine whether slugs could act as novel vectors for pathogen (e.g., Escherichia coli O157) transfer from animal feces to salad vegetables. Escherichia coli O157 was isolated from 0.21% of field slugs from an Aberdeenshire sheep farm. These isolates carried the verocytotoxin genes (vt1 and vt2) and the attaching and effacing gene (eae), suggesting that they are potentially pathogenic to humans. Strain typing using multilocus variable number tandem repeats analysis showed that slug and sheep isolates were indistinguishable. Laboratory experiments using an E. coli mutant resistant to nalidixic acid showed that the ubiquitous slug species Deroceras reticulatum could carry viable E. coli on its external surface for up to 14 days. Slugs that had been fed E. coli shed viable bacteria in their feces with numbers showing a short but statistically significant linear log decline. Further, it was found that E. coli persisted for up to 3 weeks in excreted slug feces, and hence, we conclude that slugs have the potential to act as novel vectors of E. coli O157. PMID:16391036

Sproston, Emma L; Macrae, M; Ogden, Iain D; Wilson, Michael J; Strachan, Norval J C

2006-01-01

198

Inactivation of Escherichia coli by titanium dioxide photocatalytic oxidation.  

EPA Science Inventory

Titanium dioxide in the anatase crystalline form was used as a photocatalyst to generate hydroxyl radicals in a flowthrough water reactor. Experiments were performed on pure cultures of Escherichia coli in dechlorinated tap water and a surface water sample to evaluate the disinfe...

199

Regulated expression of the Escherichia coli dam gene.  

PubMed

Regulated expression of the Escherichia coli dam gene has been achieved with the araBAD promoter lacking a ribosome binding site. Cultures of dam mutants containing plasmid pMQ430 show no detectable methylation in the absence of arabinose and complete methylation in its presence. Dam methyltransferase is a substrate for the Lon protease. PMID:12897023

Calmann, Melissa A; Marinus, M G

2003-08-01

200

Regulated Expression of the Escherichia coli dam Gene  

Microsoft Academic Search

Regulated expression of the Escherichia coli dam gene has been achieved with the araBAD promoter lacking a ribosome binding site. Cultures of dam mutants containing plasmid pMQ430 show no detectable methylation in the absence of arabinose and complete methylation in its presence. Dam methyltransferase is a substrate for the Lon protease.

Melissa A. Calmann; M. G. Marinus

2003-01-01

201

A DNA structural atlas for Escherichia coli1  

Microsoft Academic Search

We have performed a computational analysis of DNA structural features in 18 fully sequenced prokaryotic genomes using models for DNA curva- ture, DNA flexibility, and DNA stability. The structural values that are computed for the Escherichia coli chromosome are significantly different from (and generally more extreme than) that expected from the nucleo- tide composition. To aid this analysis, we have

Anders Gorm Pedersen; Lars Juhl Jensen; Søren Brunak; Hans-Henrik Stærfeldt; David W. Ussery

2000-01-01

202

Evolution of Escherichia coli During Growth in a Constant Environment  

Microsoft Academic Search

Populations of Escherichia coli, initiated with a single clone and maintained for long periods in glucose-limited continuous culture, developed extensive polymorphisms. In one population, examined after 765 generations, two majority and two minority types were identified. Stable mixed populations were reestablished from the isolated strains. Factors involved in the development of this polymorphism included differences in the maximum specific growth

Robert B. Helling; Christopher N. Vargas; Julian Adams

1987-01-01

203

Periodicity of cell attachment patterns during Escherichia coli biofilm development.  

PubMed

The complex architecture of bacterial biofilms inevitably raises the question of their design. Microstructure of developing Escherichia coli biofilms was analyzed under static and laminar flow conditions. Cell attachment during early biofilm formation exhibited periodic density patterns that persisted during development. Several models for the origination of biofilm microstructure are considered, including an activator-inhibitor or Turing model. PMID:12949116

Agladze, Konstantin; Jackson, Debra; Romeo, Tony

2003-09-01

204

Alteration of Escherichia coli Topoisomerase IV to Novobiocin Resistance  

Microsoft Academic Search

DNA gyrase and topoisomerase IV (topo IV) are the two essential type II topoisomerases of Escherichia coli. Gyrase is responsible for maintaining negative supercoiling of the bacterial chromosome, whereas topo IV's primary role is in disentangling daughter chromosomes following DNA replication. Coumarins, such as novobiocin, are wide-spectrum antimicrobial agents that primarily interfere with DNA gyrase. In this work we designed

Christine D. Hardy; Nicholas R. Cozzarelli

2003-01-01

205

Anaerobic Growth Yields of Aerobacter cloacae and Escherichia coli  

PubMed Central

Aerobacter cloacae UW-C83 and Escherichia coli K-12 were grown under various anaerobic environments. Yatp values were calculated by determination of cell weights and analyses for fermentation products. These Yatp values are compared with others reported in the literature. Limitation of growth by factors other than adenosine triphosphate supply is discussed. PMID:4963790

Hernandez, Eovaldo; Johnson, Marvin J.

1967-01-01

206

Genetics of ribosomal protein methylation in Escherichia coli  

Microsoft Academic Search

Two genes governing ribosomal protein methylation have been located on the map of Escherichia coli by conjugation and transduction crosses between wild-type and prm (protein methylation) mutants. The Prm phenotype of recombinants was determined by an in vitro assay of methylgroups incorporation into protein.

Charles Colson; Jacques Lhoest; Colette Urlings

1979-01-01

207

Patchiness of murein insertion into the sidewall of Escherichia coli  

Microsoft Academic Search

This paper extends, with computer techniques, the authors' previous work on the kinetics of pole wall and sidewall synthesis in Escherichia coli. These findings extend the conclusion that the nascent poles are made of entirely new material and that no new material is inserted into old poles. This requires re-evaluation of ideas in the literature about wall growth and cell

Miguel A. De Pedro; Heinz Schwarz; Arthur L. Koch

2003-01-01

208

Precursor-directed biosynthesis of curcumin analogs in Escherichia coli.  

PubMed

Curcuminoids, natural products in the rhizome of turmeric, show various biological activities, including antioxidant and antitumor activities. For this reason, curcuminoids have been focused on as potential pharmaceuticals. Exogenous supplementation with various carboxylate precursors in genetically engineered Escherichia coli cells carrying an artificially assembled pathway for curcuminoid biosynthesis led to the production of 17 unnatural curcuminoids. PMID:20208337

Katsuyama, Yohei; Hirose, Yutaka; Funa, Nobutaka; Ohnishi, Yasuo; Horinouchi, Sueharu

2010-01-01

209

Standard reference strains of Escherichia coli from natural populations.  

PubMed Central

A set of 72 reference strains of Escherichia coli isolated from a variety of hosts and geographical locations has been established for use in studies of variation and genetic structure in natural populations. The strains, which have been characterized by multilocus enzyme electrophoresis, are representative of the range of genotypic variation in the species as a whole. PMID:6363394

Ochman, H; Selander, R K

1984-01-01

210

Escherichia coli K-12: a cooperatively developed annotation snapshot--2005  

Microsoft Academic Search

The goal of this group project has been to coordinate and bring up-to-date information on all genes of Escherichia coli K-12. Annotation of the genome of an organism entails identification of genes, the boundaries of genes in terms of precise start and end sites, and description of the gene products. Known and predicted functions were assigned to each gene product

Monica Riley; Takashi Abe; Martha B. Arnaud; Mary K. B. Berlyn; Frederick R. Blattner; Roy R. Chaudhuri; Jeremy D. Glasner; Takashi Horiuchi; Ingrid M. Keseler; Takehide Kosuge; Hirotada Mori; Nicole T. Perna; Guy Plunkett; Kenneth E. Rudd; Margrethe H. Serres; Gavin H. Thomas; Nicholas R. Thomson; David Wishart; Barry L. Wanner

2006-01-01

211

Identification of the Escherichia coli Nicotinic Acid Mononucleotide Adenylyltransferase Gene  

PubMed Central

The gene (ybeN) coding for nicotinate mononucleotide adenylyltransferase, an NAD(P) biosynthetic enzyme, has been identified and overexpressed in Escherichia coli. This enzyme catalyzes the reversible adenylation of nicotinate mononucleotide and shows product inhibition. The rate of adenylation of nicotinate mononucleotide is at least 20 times faster than the rate of adenylation of nicotinamide mononucleotide. PMID:10894752

Mehl, Ryan A.; Kinsland, Cynthia; Begley, Tadhg P.

2000-01-01

212

Uropathogenic Escherichia coli Flagella Aid in Efficient Urinary Tract Colonization  

Microsoft Academic Search

In the murine model of urinary tract infections (UTI), cystitis by uropathogenic Escherichia coli (UPEC) occurs through an intimate relationship with the bladder superficial umbrella cell entailing cycles of adher- ence, invasion, intracellular bacterial community (IBC) formation, and dispersal (fluxing) from the intracel- lular environment. IBC dispersal is a key step that results in the spread of bacteria over the

Kelly J. Wright; Patrick C. Seed; Scott J. Hultgren

2005-01-01

213

Global Incidence of Carbapenemase-Producing Escherichia coli ST131  

PubMed Central

We characterized Escherichia coli ST131 isolates among 116 carbapenemase-producing strains. Of isolates from 16 countries collected during 2008–2013, 35% belonged to ST131 and were associated with blaKPC, H30 lineage, and virotype C. This study documents worldwide incidents of resistance to “last resort” antimicrobial drugs among a common pathogen in a successful sequence type. PMID:25340464

Peirano, Gisele; Bradford, Patricia A.; Kazmierczak, Krystyna M.; Badal, Robert E.; Hackel, Meredith; Hoban, Daryl J.

2014-01-01

214

The Asymmetric Flagellar Distribution and Motility of Escherichia coli  

Microsoft Academic Search

Rod-shaped bacteria such as Escherichia coli divide by binary fission. They inherit an old pole from the parent cell. The new pole is recently derived from the septum. Because the chemoreceptor accumulates linearly with time on the cell pole, the old pole carries more receptors than does the new pole. Here, further evidence is provided that the old pole appears

Liyan Ping

2010-01-01

215

Evidence for a human-specific Escherichia coli clone  

Microsoft Academic Search

Summary Escherichia coli is a widespread commensal of the vertebrate intestinal tract. Until recently, no strong association between a particular clone and a given host species has been found. However, members of the B2 subgroup VIII clone with an O81 serotype appear to be human host specific. To determine the degree of host specificity exhibited by this clone, a PCR-based

Olivier Clermont; Mathilde Lescat; Claire L. O'Brien; David M. Gordon; Olivier Tenaillon; Erick Denamur

2008-01-01

216

TRIMETHOPRIM-SULFAMETHOXAZOLE RESISTANCE IN SEWAGE ISOLATES OF ESCHERICHIA COLI  

EPA Science Inventory

The increase in resistance rates to trimehtoprim-sulfamethoxazole (TMP/SMX) in isolates of Escherichia coli has become a matter of increasing concern. This has been particularly true in reference to community acquired urinary tract infections (UTI). This study utilized sewage i...

217

Original article Resistance of Escherichia coli growing as biofilms  

E-print Network

Original article Resistance of Escherichia coli growing as biofilms to disinfectants C Ntsama by culture on tryptic soy agar (in-suspension or on-germ-carrier test) or in the form of biofilms pro- duced in a continuous culture system. The bacteria tested on germ-carriers or included in biofilms were more resistant

Boyer, Edmond

218

Cloning, expression and bioinformatics analysis of ATP sulfurylase from Acidithiobacillus ferrooxidans ATCC 23270 in Escherichia coli  

PubMed Central

Molecular studies of enzymes involved in sulfite oxidation in Acidithiobacillus ferrooxidans have not yet been developed, especially in the ATP sulfurylase (ATPS) of these acidophilus tiobacilli that have importance in biomining. This enzyme synthesizes ATP and sulfate from adenosine phosphosulfate (APS) and pyrophosphate (PPi), final stage of the sulfite oxidation by these organisms in order to obtain energy. The atpS gene (1674 bp) encoding the ATPS from Acidithiobacillus ferrooxidans ATCC 23270 was amplified using PCR, cloned in the pET101-TOPO plasmid, sequenced and expressed in Escherichia coli obtaining a 63.5 kDa ATPS recombinant protein according to SDS-PAGE analysis. The bioinformatics and phylogenetic analyses determined that the ATPS from A. ferrooxidans presents ATP sulfurylase (ATS) and APS kinase (ASK) domains similar to ATPS of Aquifex aeolicus, probably of a more ancestral origin. Enzyme activity towards ATP formation was determined by quantification of ATP formed from E. coli cell extracts, using a bioluminescence assay based on light emission by the luciferase enzyme. Our results demonstrate that the recombinant ATP sulfurylase from A. ferrooxidans presents an enzymatic activity for the formation of ATP and sulfate, and possibly is a bifunctional enzyme due to its high homology to the ASK domain from A. aeolicus and true kinases. PMID:23055613

Jaramillo, Michael L; Abanto, Michel; Quispe, Ruth L; Calderon, Julio; del Valle, Luis J; Talledo, Miguel; Ramirez, Pablo

2012-01-01

219

Maternally acquired genotoxic Escherichia coli alters offspring's intestinal homeostasis.  

PubMed

The neonatal gut is rapidly colonized by a newly dominant group of commensal Escherichia coli strains among which a large proportion produces a genotoxin called colibactin. In order to analyze the short- and long-term effects resulting from such evolution, we developed a rat model mimicking the natural transmission of E. coli from mothers to neonates. Genotoxic and non-genotoxic E. coli strains were equally transmitted to the offspring and stably colonized the gut across generations. DNA damage was only detected in neonates colonized with genotoxic E. coli strains. Signs of genotoxic stress such as anaphase bridges, higher occurrence of crypt fission and accelerated renewal of the mature epithelium were detected at adulthood. In addition, we observed alterations of secretory cell populations and gut epithelial barrier. Our findings illustrate how critical is the genotype of E. coli strains acquired at birth for gut homeostasis at adulthood. PMID:24971581

Payros, Delphine; Secher, Thomas; Boury, Michèle; Brehin, Camille; Ménard, Sandrine; Salvador-Cartier, Christel; Cuevas-Ramos, Gabriel; Watrin, Claude; Marcq, Ingrid; Nougayrède, Jean-Philippe; Dubois, Damien; Bedu, Antoine; Garnier, Fabien; Clermont, Olivier; Denamur, Erick; Plaisancié, Pascale; Theodorou, Vassilia; Fioramonti, Jean; Olier, Maïwenn; Oswald, Eric

2014-01-01

220

Experimental Escherichia coli ascending pyelonephritis in rats: active peroral immunization with live Escherichia coli.  

PubMed Central

Peroral immunization with a live strain of Escherichia coli O6K13H1 against experimental ascending pyelonephritis caused by the same strain was studied in rats, and the effect of immunization on antibody titers against the O and K antigens and lipid A was determined. Peroral immunization with live bacteria protected significantly against pyelonephritis. Sera collected 1 week after infection from the immunized group were increased in immunoglobulin G (IgG) anti-O6 and IgM anti-K13 in comparison with the nonimmunized group. The peroral immunization did not correspondingly affect the response to lipid A. In urine, there was an IgG antibody response to the O6 antigen. In bronchopulmonary secretion, IgM, IgG, and IgA antibodies to O6 were detected. Perorally immunized animals had significantly higher levels of IgG and IgA anti-O6 compared with the nonimmunized group 1 week after infection. Passive transfer of anti-lipid A did not increase resistance against pyelonephritis. PMID:7035370

Mattsby-Baltzer, I; Hanson, L A; Olling, S; Kaijser, B

1982-01-01

221

Restriction-Stimulated Homologous Recombination of Plasmids by the Rece Pathway of Escherichia Coli  

PubMed Central

To test the double-strand break (DSB) repair model in recombination by the RecE pathway of Escherichia coli, we constructed chimeric phages that allow restriction-mediated release of linear plasmid substrates of the bioluminescence recombination assay in infected EcoRI(+) cells. Kinetics of DSB repair and expression of recombination products were followed by Southern hybridization and by the bioluminescence recombination assay, respectively. Plasmid recombinants were analyzed with restriction endonucleases. Our results indicate that a DSB can induce more than one type of RecE-mediated recombination. A DSB within the homology induced intermolecular recombination that followed the rules of the DSB repair model: (1) Recombination was enhanced by in vivo restriction. (2) Repair of the break depended on homologous sequences on the resident plasmid. (3) Break-repair was frequently associated with conversion of alleles that were cis to the break. (4) Conversion frequency decreased as the distance from the break increased. (5) Some clones contained a mixture of plasmid recombinants as expected by replication of a heteroduplex in the primary recombinant. The rules of the DSB repair model were not followed when recombination was induced by a DSB outside the homology. Both the cut and the uncut substrates were recipients in conversion events. Recombination events were associated with deletions that spanned the break site, but these deletions did not reach the homology. We propose that a break outside the homology may stimulate a RecE-mediated recombination pathway that does not involve direct participation of DNA ends in the homologous pairing reaction. PMID:1732167

Nussbaum, A.; Shalit, M.; Cohen, A.

1992-01-01

222

Estimation of Escherichia coli in raw ground beef.  

PubMed Central

This study was undertaken to establish and evaluate more rapid methods of estimating Escherichia coli in ground beef than the standard most probable number (MPN) technique. Direct inoculation of and modifications to EC medium gave unreliable estimates of the presumptive E. coli count. Solid media incubated at an elevated temperature were compared to the MPN technique. Anderson and Baird-Parker's tryptone bile agar (TBA) method and prepoured plates of Endo, Levine eosin methylene blue (EMB), and violet red bile (VRBA) agars incubated at 44 degree C gave equivalent counts to the standard MPN method. Anderson and Baird-Parker TBA was the most selective solid medium for E. coli estimation, but all selective media incubated at elevated temperature reduced apparent E. coli counts by as much as 50%. Indole-producing and lactose-fermenting Enterobacteriaceae, capable of growth at elevated temperature, were tested for their growth on TBA, EMB, and VRBA at elevated temperature. TBA was selective for E. coli biotype I compared to other Enterobacteriaceae that predominate in meats. VRBA and EMB incubated at elevated temperature were not as selective as TBA, but differences in colonies could be observed between typical E. coli colonies and other Enterobacteriaceae on these media. Therefore, VRBA incubated at elevated temperature is proposed as a quality assurance screening test for presumptive E. coli in ground meat. Resuscitation techniques and prepoured plates with VRBA increased recovery levels of presumptive E. coli, but, under the conditions of this study, not to levels that represented a significant practical difference. PMID:7008695

Stiles, M E; Ng, L K

1980-01-01

223

Food Reservoir for Escherichia coli Causing Urinary Tract Infections  

PubMed Central

Closely related strains of Escherichia coli have been shown to cause extraintestinal infections in unrelated persons. This study tests whether a food reservoir may exist for these E. coli. Isolates from 3 sources over the same time period (2005–2007) and geographic area were compared. The sources comprised prospectively collected E. coli isolates from women with urinary tract infection (UTI) (n = 353); retail meat (n = 417); and restaurant/ready-to-eat foods (n = 74). E. coli were evaluated for antimicrobial drug susceptibility and O:H serotype and compared by using 4 different genotyping methods. We identified 17 clonal groups that contained E. coli isolates (n = 72) from >1 source. E. coli from retail chicken (O25:H4-ST131 and O114:H4-ST117) and honeydew melon (O2:H7-ST95) were indistinguishable from or closely related to E. coli from human UTIs. This study provides strong support for the role of food reservoirs or foodborne transmission in the dissemination of E. coli causing common community-acquired UTIs. PMID:20031048

Vincent, Caroline; Boerlin, Patrick; Daignault, Danielle; Dozois, Charles M.; Dutil, Lucie; Galanakis, Chrissi; Reid-Smith, Richard J.; Tellier, Pierre-Paul; Tellis, Patricia A.; Ziebell, Kim

2010-01-01

224

Steady-State Chemotaxis in Escherichia coli  

Microsoft Academic Search

The bacterium E. coli maneuvers itself to regions with high chemoattractant concentrations by performing two stereotypical moves: ``runs,'' in which it moves in near-straight lines, and ``tumbles,'' in which it does not advance but changes direction randomly. The duration of each move is stochastic and depends upon the chemoattractant concentration experienced in the recent past. We relate this stochastic behavior

Yariv Kafri; Rava Azeredo da Silveira

2008-01-01

225

Temporal Stimulation of Chemotaxis in Escherichia coli  

Microsoft Academic Search

We used the tracking microscope to study the chemotactic responses of E. coli to temporal gradients of L-glutamate generated in isotropic solutions by the action of the enzyme alanine aminotransferase. Positive gradients suppress directional changes which occur spontaneously in the absence of a stimulus. Negative gradients have little effect. The data can be fit with a model in which the

Douglas A. Brown; Howard C. Berg

1974-01-01

226

Food-borne origins of Escherichia coli causing extraintestinal infections.  

PubMed

Most human extraintestinal Escherichia coli infections, including those involving antimicrobial resistant strains, are caused by the members of a limited number of distinctive E. coli lineages, termed extraintestinal pathogenic E. coli (ExPEC), that have a special ability to cause disease at extraintestinal sites when they exit their usual reservoir in the host's intestinal tract. Multiple lines of evidence suggest that many of the ExPEC strains encountered in humans with urinary tract infection, sepsis, and other extraintestinal infections, especially the most extensively antimicrobial-resistant strains, may have a food animal source, and may be transmitted to humans via the food supply. This review summarizes the evidence that food-borne organisms are a significant cause of extraintestinal E. coli infections in humans. PMID:22615330

Manges, Amee R; Johnson, James R

2012-09-01

227

Polyserositis Induced by Escherichia coli in Gnotobiotic Swine.  

PubMed

The oral administration of an 18-hr broth culture of Escherichia coli 06: isolated from a cat to 3-day-old gnotobiotic (germ-free) piglets resulted in bacteremia and polyserositis. Sixteen pigs, selected from four litters, were used in the study. E. coli of the same serotype employed was the only bacterial agent demonstrable and recovered from moribund and dead piglets. Attempts to recover virus or PPLO (mycoplasma) from these animals were unsuccessful. A polyserositis syndrome was not encountered among neonatal pigs in experiments with 14 other serotypes of E. coli; hence it was considered to be a syndrome closely associated with the infection caused by this particular strain of E. coli. PMID:16557944

Meyer, R C; Saxena, S P; Rhoades, H E

1971-01-01

228

Biosynthesis of bioactive O-methylated flavonoids in Escherichia coli.  

PubMed

Two bioactive O-methylflavonoids, sakuranetin (7-O-methylnaringenin) and ponciretin (7-O-methylnaringenin), were synthesized in Escherichia coli. Sakuranetin inhibits germination of Magnaporthe grisea, and ponciretin is a potential inhibitor of Helicobacter pylori. To achieve this, we reconstructed the naringenin biosynthesis pathway in E. coli. First, the shikimic acid pathway, which leads to the biosynthesis of tyrosine, was engineered in E. coli to increase the amount of available tyrosine. Second, several genes for the biosynthesis of ponciretin and sakuranetin such as tyrosine ammonia lyase (TAL), 4-coumaroyl CoA ligase (4CL), chalcone synthase (CHS), and O-methyltransferase (OMT) were overexpressed. In order to increase the supply the Coenzyme A (CoA), one gene (icdA, isocitrate dehydrogenase) was deleted. Using these strategies, we synthesized ponciretin and sakuranetin from glucose in E. coli at the concentration of 42.5 mg/L and 40.1 mg/L, respectively. PMID:23771780

Kim, Min-Ji; Kim, Bong-Gyu; Ahn, Joong-Hoon

2013-08-01

229

ROLE OF NUTRITION IN THE PATHOGENESIS OF PORCINE ESCHERICHIA COLI ENTEROTOXAEMIA  

E-print Network

ROLE OF NUTRITION IN THE PATHOGENESIS OF PORCINE ESCHERICHIA COLI ENTEROTOXAEMIA H.U. BERTSCHINGER growth of a few serotypes of haemolytic E. coli in the small intestine. Correspondingly to E. coli. coli enterotoxaemia was studied in weaned pigs inoculated with a field strain of E. coli 0139:K821BI

Boyer, Edmond

230

Enteropathogenic Escherichia coli Prevalence in Laboratory Rabbits  

PubMed Central

Rabbit-origin enteropathogenic E. coli (EPEC) causes substantial diarrhea-associated morbidity and has zoonotic potential. A culture-based survey was undertaken to ascertain its prevalence. EPEC was isolated from 6/141 (4.3%) commercially-acquired laboratory rabbits. Three of these did not have diarrhea or EPEC-typical intestinal lesions; they instead had background plasmacytic intestinal inflammation. Asymptomatically infected rabbits may function as EPEC reservoirs. PMID:23391439

Swennes, Alton G.; Buckley, Ellen M.; Madden, Carolyn M.; Byrd, Charles P.; Donocoff, Rachel S.; Rodriguez, Loretta; Parry, Nicola M. A.; Fox, James G.

2013-01-01

231

Genetic Transformation in Escherichia coli K12  

Microsoft Academic Search

An auxotrophic strain of E. coli K12 treated with CaCl2 was transformed for several markers at a frequency of up to 10-6 per recipient cell by a DNA preparation isolated from a prototrophic strain. The transforming activity of the DNA preparation was eliminated by treatment with DNase, heat, or sonication, whereas RNase or Pronase treatment had little effect. Two closely

Sharon D. Cosloy; Michio Oishi

1973-01-01

232

DNA Methylation and Mutator Genes in Escherichia coli K-12  

PubMed Central

Mutator strains of Escherichia coli have been used to define mechanisms that account for the high fidelity of chromosome duplication and chromosome stability. Mutant strains defective in post-replicative mismatch repair display a strong mutator phenotype consistent with a role for correction of mismatches arising from replication errors. Inactivation of the gene (dam) encoding DNA adenine methyltransferase results in a mutator phenotype consistent with a role for DNA methylation in strand discrimination during mismatch repair. This review gives a personal perspective on the discovery of dam mutants in E. coli and their relationship to mismatch repair and mutator phenotypes. PMID:20471491

Marinus, Martin G.

2010-01-01

233

Copper, zinc superoxide dismutase in Escherichia coli: periplasmic localization.  

PubMed

Cu,ZnSOD purified from Escherichia coli has been used to raise antibodies in rabbits. The resultant antiserum was found to recognize a single band on Western blots of SDS-polyacrylamide gel electropherograms, and that single band coincided with the position of the Cu,ZnSOD. Ultrathin sections of fixed E. coli were treated with the antibody followed by protein A bearing 10-nm gold particles. Electron microscopy revealed that Cu,ZnSOD was largely localized in the periplasm in polar bays. PMID:7786035

Benov, L; Chang, L Y; Day, B; Fridovich, I

1995-06-01

234

Accelerated glycerol fermentation in Escherichia coli using methanogenic formate consumption.  

PubMed

Escherichia coli can ferment glycerol anaerobically only under very defined restrictive conditions. Hence, it was the aim of this study to overcome this limitation via a co-cultivation approach. Anaerobic glycerol fermentation by a pure E. coli culture was compared to a co-culture that also contained the formate-oxidizing methanogen Methanobacterium formicicum. Co-cultivation of the two strains led to a more than 11-fold increased glycerol consumption. Furthermore, it supported a constantly neutral pH and a shift from ethanol to succinate production. Moreover, M. formicicum was analyzed for its ability to grow on different standard media and a surprising versatility could be demonstrated. PMID:24785787

Richter, Katrin; Gescher, Johannes

2014-06-01

235

Effect of Escherichia coli enterotoxins on macromolecular absorption.  

PubMed Central

Macromolecular absorption of gliadin, a wheat protein and alpha lactalbumin, a milk protein was evaluated in control and Escherichia coli enterotoxin (heat-stable, heat-labile, and both heat-stable and heat-labile enterotoxin) treated mice. The peak concentration of gliadin and lactalbumin was two hours and three hours after their ingestion, respectively. There was also a significant increase (p < 0.01) in the absorption of both the proteins in all the three toxin treated groups compared with the control group. These results suggest that intestinal permeability and macromolecular absorption changes after E coli infection. PMID:7828983

Verma, M; Majumdar, S; Ganguly, N K; Walia, B N

1994-01-01

236

Uncoupler Resistance in Escherichia coli: the Role of Cellular Respiration  

Microsoft Academic Search

Bioenergetic properties of a mutant strain of Escherichia coli K12 designated TUV, which is resistant to the protonophoric uncoupling agent 4,5,6,7-tetrachloro-2-trifluoromethylbenzimid- azole (TTFB) have been compared with those of its non-resistant parent, E. coli K12 Doc-S. Strain TUV grew and respired some 20-30% faster than strain Doc-S, and was cross-resistant to carbonylcyanide p-(trifluoromethoxy)phenylhydrazone and triphenyltin, but not to 2,4- dinitrophenol.

PHILIP G. QUIRK; MICHAEL R. JONES; ROBERT S. HAWORTH; R. BRIAN BEECHEY; IAIN D. CAMPBELL

1989-01-01

237

Recombinant protein expression in Escherichia coli: advances and challenges  

PubMed Central

Escherichia coli is one of the organisms of choice for the production of recombinant proteins. Its use as a cell factory is well-established and it has become the most popular expression platform. For this reason, there are many molecular tools and protocols at hand for the high-level production of heterologous proteins, such as a vast catalog of expression plasmids, a great number of engineered strains and many cultivation strategies. We review the different approaches for the synthesis of recombinant proteins in E. coli and discuss recent progress in this ever-growing field. PMID:24860555

Rosano, German L.; Ceccarelli, Eduardo A.

2014-01-01

238

DNA methylation and mutator genes in Escherichia coli K-12.  

PubMed

Mutator strains of Escherichia coli have been used to define mechanisms that account for the high fidelity of chromosome duplication and chromosome stability. Mutant strains defective in post-replicative mismatch repair display a strong mutator phenotype consistent with a role for correction of mismatches arising from replication errors. Inactivation of the gene (dam) encoding DNA adenine methyltransferase results in a mutator phenotype consistent with a role for DNA methylation in strand discrimination during mismatch repair. This review gives a personal perspective on the discovery of dam mutants in E. coli and their relationship to mismatch repair and mutator phenotypes. PMID:20471491

Marinus, Martin G

2010-10-01

239

Bacterial self-defence: how Escherichia coli evades serum killing.  

PubMed

The ability to survive the bactericidal action of serum is advantageous to extraintestinal pathogenic Escherichia coli that gain access to the bloodstream. Evasion of the innate defences present in serum, including complement and antimicrobial peptides, involves multiple factors. Serum resistance mechanisms utilized by E. coli include the production of protective extracellular polysaccharide capsules and expression of factors that inhibit or interfere with the complement cascade. Recent studies have also highlighted the importance of structural integrity of the cell envelope in serum survival. These survival strategies are outlined in this review with particular attention to novel findings and recent insights into well-established resistance mechanisms. PMID:24617921

Miajlovic, Helen; Smith, Stephen G

2014-05-01

240

Determination and quantification of Escherichia coli by capillary electrophoresis.  

PubMed

Capillary electrophoresis (CE) is widely employed for the separation of nucleic acids or protein, but it is rarely applied in the quantification of Escherichia coli (E. coli). Here, we have analysed E. coli by CE with mercury lamp induced fluorescence, and demonstrated the relationship between its fluorescence intensity with the concentration of E. coli for the first time. The gradient concentration of E. coli was obtained by polymerase chain reaction (PCR) with different amplification cycles and dilution certain PCR products of E. coli, respectively. Results show that the peak area was linearly related to the logarithm of the concentration of E. coli and the logarithm of PCR replication numbers. The correlation coefficients R(2) are 0.957 and 0.966, respectively. The limit of detection (LOD) was found to be about 8.913 × 10(-15) mol ?l(-1). The reproducibility of capillary electrophoresis may make this technique possible for quantitative measurement of bacteria in bio-analytical science. PMID:25307062

Li, Zhenqing; Li, De; Zhang, Dawei; Yamaguchi, Yoshinori

2014-10-27

241

Escherichia Coli: an Important Pathogen in Patients with Hematologic Malignancies  

PubMed Central

Background Escherichia coli (E. coli) is a pathogen of great concern in immunosuppressed patients. While antimicrobial prophylactic therapy has become the standard, the emergence of resistant pathogens has some questioning its use. This study describes our experience with E.coli as a pathogen in neutropenic patients with a hematologic malignancy, and addresses future directions of treatment for this patient population. Methods A retrospective chart review of 245 E.coli bacteremia patients at Moffitt Cancer Center from 05/18/02 – 05/15/12 was conducted. Out of 245 patients, 169 did not meet the criteria due to non-neutropenic status, or not diagnosed with a hematologic malignancy, or due to having insufficient medical records. Thus, they were excluded from the study. As a result, 76 patients were involved in this study. Patients were identified via microbiology laboratory computerized records. Results The included patients experienced clinically significant E.coli bacteremia resulting in a median hospital stay of 14.7 days. Several patients developed severe sepsis requiring the use of pressor and ventilator therapy. Conclusions E.coli is a major pathogen in these patient populations resulting in extended hospital stays and specialized treatment to overcome their E.coli bacteremia. The data supports the use of fluoroquinolone prophylactic therapy, however, earlier detection and treatment of neutropenic infection is needed. PMID:25408854

Olson, Daniel; Yacoub, Abraham T.; Gjini, Anita D.; Domingo, Gelenis; Greene, John N.

2014-01-01

242

Pathotyping blaCTX-M Escherichia coli from Nigeria  

PubMed Central

Background: Escherichia coli have become the enterobacteriaceae species most affected by extended-spectrum ?-lactamases (ESBLs) in view of the emergence of CTX-M-type ESBLs. These CTX-M-positive E. coli have been reported in numerous regions worldwide. Virulence determinants of already reported CTX-M-positive E. coli were investigated. Methodology: To gain insights into the mechanism underlying this phenomenon, we assessed serogroup, susceptibility pattern and diversity of virulence profiles within a collection of nine blaCTX-M-positive E. coli strains and their virulent determinant using miniaturized DNA microarray techniques. The nine ESBL-positive E. coli isolates were from eight male and one female patient(s) selected for study based on previous work. Virulence potential was inferred by detection of 63 virulence factor (VF) genes. Results: Four (44.4%) of the 9 E. coli isolates exhibited the same set of core characteristics: serotype O8:Hnt, while all were positive for OXA-1, ciprofloxacin resistance. Five of the isolates exhibited highly similar (91% to 100%) VF profiles. Conclusion: The findings describe a broadly disseminated, blaCTX-M-positive and virulent E. coli serogroup with highly homogeneous virulence genotypes, suggesting recent emergence in this zone. Understanding how this clone has emerged and successfully disseminated within the hospital and community, including across national boundaries, should be a public health priority. PMID:24265928

Olowe, Olugbenga Adekunle; Choudhary, Suman; Schierack, Peter; Wieler, Lothar H.; Olayemi, Albert B.; Anjum, Muna

2013-01-01

243

Competitive inhibition of adherence of enterotoxigenic Escherichia coli, enteropathogenic Escherichia coli and Clostridium difficile to intestinal epithelial cell line Lovo by purified adhesin of Bifidobacterium adolescentis 1027  

Microsoft Academic Search

AIM: To observe competitive inhibition of adherence of enterotoxigenic Escherichia coli (ETEC), enteropathogenic Escherichia coli (EPEC) and Clostridium difficile (C. difficile) to intestinal epithelial cell line Lovo by purified adhesin of Bifidobacterium adolescentis 1027 (B. ado 1027). METHODS: The binding of bacteria to intestinal epithelial cell line Lovo was counted by adhesion assay. The inhibition of adherence of ETEC, EPEC

Shi-Shun Zhong; Zhen-Shu Zhang; Ji-De Wang; Zhuo-Sheng Lai; Qun-Ying Wang; Ling-Jia Pan; Yue-Xin Ren

2004-01-01

244

Transcriptome-based determination of multiple transcription regulator activities in Escherichia coli  

E-print Network

network connectiv- ity. We used Escherichia coli carbon source transition from glucose to acetate the Escherichia coli transition from glucose to acetate media as an example. When switching from a glycolyticTranscriptome-based determination of multiple transcription regulator activities in Escherichia

Sabatti, Chiara

245

In vivo translation rates can substantially delay the cotranslational folding of the Escherichia coli  

E-print Network

results indicate that, at in vivo translation rates, about one-third of the Escherichia coli cytosolic in Escherichia coli's proteome. systems biology | synonymous codons | chemical kinetics | chaperone | aggregationIn vivo translation rates can substantially delay the cotranslational folding of the Escherichia

Morimoto, Richard

246

An Experimental Evolutionary Study on Adaptation to Temporally Fluctuating pH in Escherichia coli  

E-print Network

Published 5/2/2007 ABSTRACT In this study, we use the bacterium Escherichia coli to examine evolutionary because of the importance of this environmental stressor to enteric bac- teria such as Escherichia coli406 An Experimental Evolutionary Study on Adaptation to Temporally Fluctuating pH in Escherichia

Bennett, Albert F.

247

Variation of the folding and dynamics of the Escherichia coli chromosome with growth conditions  

E-print Network

Variation of the folding and dynamics of the Escherichia coli chromosome with growth conditions Biosciences, Northwestern University, Evanston, IL 60208, USA. Summary We examine whether the Escherichia coli slow growth where there is one complete cycle of DNA replica- tion per cell division, the Escherichia

Kowalczykowski, Stephen C.

248

A Case of a Shiga Toxin Producing Escherichia Coli  

E-print Network

contributed equally to this work. We encountered a patient with hemolytic uremic syndrome (HUS) with persistent isolation of shiga toxin-producing Escherichia coli (STEC) for 3 weeks despite of having no clinical symptoms. STEC has been recognized as an important foodborne pathogen that causes severe diseases such as HUS. We characterized this STEC strain via a polymerase chain reaction, reverse-passive latex agglutination and the slide agglutination method. In this STEC strain, stx2 (shiga toxin), eaeA, tir, iha (adherence genes), espADB (type III secretion genes), and hlyA, ehxA, clyA (hemolysin genes) were present. The O antigen of the strain was non-typable. Key Words: ?Shiga toxin-producing Escherichia coli, hemolytic uremic syndrome, non-typable serotype STEC strain ? The authors have no financial conflicts of

Seung-hak Cho Jung-beom Kim; Hiun Suk Chae; Hae Kyung Lee; Corresponding Dr; Hae Kyung Lee; Seung-hak Cho; Jung-beom Kim

2011-01-01

249

Enterotoxigenic Escherichia coli infection in captive black-footed ferrets.  

PubMed

Enterotoxigenic Escherichia coli with genes for heat stabile toxins Sta and STb was isolated from the gastrointestinal tract and multiple visceral organs of three adult and three juvenile black-footed ferrets (Mustela nigripes) that died in a captive breeding colony between 24 May 1998 and 2 July 1998. Similar isolates were obtained from rectal swabs of one adult and one juvenile that were clinically ill. All were fed a diet composed of mink chow, raw rabbit meat, beef liver powder, blood meal and lard. Escherichia coli of the same toxin genotype was isolated from the mixed ration. Clinical signs included sudden death, dehydration, anorexia and diarrhea. Necropsy lesions included acute enteritis with large numbers of rod shaped bacteria microscopically visible on intestinal villi. PMID:11504237

Bradley, G A; Orr, K; Reggiardo, C; Glock, R D

2001-07-01

250

Evaluating Representations for the Shine-Dalgarno Site in Escherichia coli  

E-print Network

Evaluating Representations for the Shine-Dalgarno Site in Escherichia coli Steven Hampson & Dennis 10) are applied to the pooled Upstream Regions (USR) of all 4289 Escherichia coli ORFs. Instances) but most genes in E. coli have an identifiable SD sequence in the expected location. On the other hand, up

Kibler, Dennis F.

251

LETTER TO THE EDITOR Aminoacylated tmRNA from Escherichia coli  

E-print Network

LETTER TO THE EDITOR Aminoacylated tmRNA from Escherichia coli interacts with prokaryoticRNAs (10Sa RNAs) are unique because they function, at least in Escherichia coli, both as tRNA and mRNA (for frame coding for 9 to 27 amino acids, depending on the species+ E. coli tmRNA mediates re- cycling

Paris-Sud XI, Université de

252

Design and Diversity in Bacterial Chemotaxis: A Comparative Study in Escherichia coli  

E-print Network

Design and Diversity in Bacterial Chemotaxis: A Comparative Study in Escherichia coli and Bacillus such as Escherichia coli and Bacillus subtilis, swimming alternates between smooth runs and reorientating tumbles, in particular the feedback control structure, is also conserved. The bacterial chemotaxis pathways in E. coli

Fernando, Chrisantha

253

The Roles of Specific Template Nucleosides in the Formation of Stable Transcription Complexes by Escherichia coli  

E-print Network

by Escherichia coli RNA Polymerase* (Received for publication, September 13, 1999, and in revised form, December/or initiation. The initiation of transcription by Escherichia coli RNA po- lymerase involves not only DNA nucleosides on promoter escape by Esche- richia coli RNA polymerase in vitro. The ability of DNA templates

Tullius, Thomas D.

254

Is there a Liquid State Machine in the Bacterium Escherichia Coli?  

E-print Network

Is there a Liquid State Machine in the Bacterium Escherichia Coli? Ben Jones, Dov Stekelo, Jon Rowe, UK Email: C.T.Fernando@cs.bham.ac.uk Abstract-- The bacterium Escherichia coli has the capacity, E.Coli's capacity for perceptual categorization, especially for discrimination between complex

Rowe, Jon

255

Escherichia coli identification and strain discrimination using nanosecond laser-induced breakdown spectroscopy  

E-print Network

Escherichia coli identification and strain discrimination using nanosecond laser-induced breakdown April 2007 Three strains of Escherichia coli, one strain of environmental mold, and one strain and E. coli strains. This analysis showed efficient discrimination between laser-induced breakdown

Rehse, Steven J.

256

THE TEMPERATURE-LIMITED FED-BATCH TECHNIQUE FOR CONTROL OF ESCHERICHIA COLI CULTURES  

E-print Network

THE TEMPERATURE-LIMITED FED-BATCH TECHNIQUE FOR CONTROL OF ESCHERICHIA COLI CULTURES MARIE SVENSSON The objective of this study was to investigate the physiology and productivity in Escherichia coli cultures of endotoxins were found in the medium of E. coli fed-batch cultures at low specific growth rates (below 0.1 h-1

Enfors, Sven-Olof

257

Development of a Native Escherichia coli Induction System for Ionic Liquid Tolerance  

E-print Network

Development of a Native Escherichia coli Induction System for Ionic Liquid Tolerance Marijke the growth and function of biofuel-producing microorganisms. In E. coli this toxicity can be partially J, Batth TS, Turner WJ, et al. (2014) Development of a Native Escherichia coli Induction System

Dunlop, Mary

258

A Novel Methyltransferase Catalyzes the Methyl Esterification of trans-Aconitate in Escherichia coli*  

E-print Network

-adenosyl-L-methi- onine-dependent methyltransferase in the cytosol of Escherichia coli that is expressed in early-out strain of E. coli lacking this activity, and we find that its growth and stationary phase survival). In the bacterium Escherichia coli, this enzyme is required for optimal survival of stationary phase cells against

Clarke, Steven

259

Antisense phosphorodiamidate morpholino oligomer inhibits viability of Escherichia coli in pure culture  

E-print Network

Antisense phosphorodiamidate morpholino oligomer inhibits viability of Escherichia coli in pure of Escherichia coli. Previously, an 11 base PMO targeted to an essential gene (acpP) for phospholipid biosynthesis was shown to inhibit growth of a pure culture of E. coli AS19, which has an abnormally permeable

Hammerton, James

260

CONTROL OF PYRIMIDINE BIOSYNTHESIS IN ESCHERICHIA COLI BY A FEED-BACK MECHANISM*  

E-print Network

CONTROL OF PYRIMIDINE BIOSYNTHESIS IN ESCHERICHIA COLI BY A FEED-BACK MECHANISM* BY RICHARD A of purine- requiring Escherichia coli mutants caused inhibition of formation of two purine precursors the growth factor, valine, inhibited formation in an E. coli mutant of a-ketoisovalerate, a valine precursor

Bulyk, Martha L.

261

Self-Organization of the Escherichia coli Chemotaxis Network Imaged with Super-Resolution Light Microscopy  

E-print Network

Self-Organization of the Escherichia coli Chemotaxis Network Imaged with Super-Resolution Light of California Berkeley, Berkeley, California, United States of America Abstract The Escherichia coli chemotaxis network is a model system for biological signal processing. In E. coli, transmembrane receptors

262

AICAR is not an endogenous mutagen in Escherichia coli  

Microsoft Academic Search

A number of observations in the Escherichia coli and Salmonella typhimurium literature could be explained by the hypothesis that a particular purine ribonucleotide precursor can be converted to the corresponding deoxyribonucleotide triphosphate, thereby becoming a base-analogue mutagen. The metabolite in question, AICAR (5-amino-4-carboxamide imidazole riboside 5'-phosphate), is also a by-product of histidine biosynthesis, and its (ribo)triphosphate derivative, ZTP, has been

Maurice Fox; Niels Frandsen; Richard D'Ari

1993-01-01

263

On Torque and Tumbling in Swimming Escherichia coli  

Microsoft Academic Search

Bacteria swim by rotating long thin helical filaments, each driven at its base by a reversible rotary motor. When the motors of peritrichous cells turn counterclockwise (CCW), their filaments form bundles that drive the cells forward. We imaged fluorescently labeled cells of Escherichia coli with a high-speed charge-coupled- device camera (500 frames\\/s) and measured swimming speeds, rotation rates of cell

Nicholas C. Darnton; Linda Turner; Svetlana Rojevsky; Howard C. Berg

2007-01-01

264

Escherichia coli lipopolysaccharide inhibits renin activity in human mesangial cells  

Microsoft Academic Search

Hyperactivation of systemic renin–angiotensin system (RAS) during sepsis is well documented. However, the behavior of intrarenal RAS in the context of endotoxemia is yet to be defined. The present study evaluates the direct effect of Escherichia coli lipopolysaccharide (LPS) on immortalized human mesangial cell (HMC) RAS. Quiescent HMC were incubated with vehicle or LPS (1–100 ?g\\/ml), and levels of angiotensin

W S Almeida; T T Maciel; G S Di Marco; D E Casarini; A H Campos; N Schor

2006-01-01

265

Expression and characterization of Pichia etchellsii ?-glucosidase in Escherichia coli  

Microsoft Academic Search

The ?-glucosidase enzyme is important as the terminal enzyme involved in hydrolysis of cellobiose and short-chain cellodextrins generated during enzymatic cellulose degradation. Under controlled reaction conditions the enzyme also displays cello-oligosaccharide synthesizing ability (based on either the thermodynamic or kinetic approach). We present here the purification of the enzyme ?-glucosidase (BGL) of Pichia etchellsii from recombinant pBG55 Escherichia coli clone.

Manjula Pandey; Saroj Mishra

1997-01-01

266

Electric field induced bacterial flocculation of enteroaggregative Escherichia coli 042  

NASA Astrophysics Data System (ADS)

A response of the aggregation dynamics of enteroaggregative Escherichia coli under low magnitude steady and oscillating electric fields is presented. The presence of uniform electric fields hampered microbial adhesion and biofilm formation on a transverse glass surface, but instead promoted the formation of flocs. Extremely heterogenous distribution of live and dead cells was observed among the flocs. Moreover, floc formation was largely observed to be independent of the frequency of alternating electric fields.

Kumar, Aloke; Mortensen, Ninell P.; Mukherjee, Partha P.; Retterer, Scott T.; Doktycz, Mitchel J.

2011-06-01

267

Effect of acid mine water on Escherichia coli : Structural Damage  

Microsoft Academic Search

Escherichia coli B\\/5 12-h cultures were exposed to filter-sterilized acid mine water (AMW), fixed in situ, and examined for morphological changes by transmission electron microscopy, scanning electron microscopy, and x-ray spectrometry. Thin sections showed that layers of the Gram-negative envelope were altered and often lacking. Additionally, polar regions of the cell were frequently devoid of cytoplasm. AMW-exposed cells were distorted

Alan T. Wortman; H. Voelz; R. Clark Lantz; Gary K. Bissonnette

1986-01-01

268

Evidence of Pathogenic Subgroups among Atypical Enteropathogenic Escherichia coli Strains?  

PubMed Central

We describe the characterization of 126 atypical enteropathogenic Escherichia coli (aEPEC) isolates from 1,749 Brazilian children. Classic aEPEC strains were more frequently found in children with diarrhea than in controls (P < 0.001), showing their importance as acute diarrhea agents in our country. Only aEPEC strains carrying either the ehxA or paa gene were significantly associated with diarrhea. PMID:19759223

Scaletsky, Isabel C. A.; Aranda, Katia R. S.; Souza, Tamara B.; Silva, Neusa P.; Morais, Mauro B.

2009-01-01

269

Survival and Plasmid Transfer Ability of Escherichia Coli in Wastewater  

Microsoft Academic Search

No differences were observed in the survival of plasmid-bearingand plasmid-free Escherichia coli strains in the course of a long-term survival process in wastewater, under both illuminated and non-illuminated conditions. While the CFU counts and the number of active cells decreased, the numberof nucleoid-containing cells remained constant throughout the 30 days of experimentation. Visible light efficiently contributed to the reduction in

I. Arana; J. I. Justo; A. Muela; I. Barcina

2001-01-01

270

Electric field induced bacterial flocculation of Enteroaggregative Escherichia coli 042  

SciTech Connect

A response of the aggregation dynamics of enteroaggregative Escherichia coli under low magnitude steady and oscillating electric fields is presented. The presence of uniform electric fields hampered microbial adhesion and biofilm formation on a transverse glass surface, but instead promoted the formation of flocs. Extremely heterogeneous distribution of live and dead cells was observed among the flocs. Moreover, floc formation was largely observed to be independent of the frequency of alternating electric fields.

Kumar, Aloke [ORNL; Mortensen, Ninell P [ORNL; Mukherjee, Partha P [ORNL; Retterer, Scott T [ORNL; Doktycz, Mitchel John [ORNL

2011-01-01

271

Nucleoids Dynamic in Escherichia coli: A Growth Phase Dependent Process  

Microsoft Academic Search

Bacterial DNA compacts in nucleoid bodies. The organization of nucleoid body depends on the association of genomic DNA with a numbers of histone-like proteins. The relax nucleoids organization in rapidly growing Escherichia coli cells associate with six major proteins, Fis, HU, Hfq, H-NS, StpA and IHF, but at stationary phase the nucleoids further tightly pack with Dps. The final steps

Ali Azam Talukder; M Anwar Hossain; Mamoru Yamada; Akira Ishihama

2006-01-01

272

Genomic Islands of Uropathogenic Escherichia coli Contribute to Virulence  

Microsoft Academic Search

Uropathogenic Escherichia coli (UPEC) strain CFT073 contains 13 large genomic islands ranging in size from 32 kb to 123 kb. Eleven of these genomic islands were individually deleted from the genome, and nine isogenic mutants were tested for their ability to colonize the CBA\\/J mouse model of ascending urinary tract infection. Three genomic island mutants (PAI-aspV, PAI-metV, and PAI-asnT) were

Amanda L. Lloyd; Tiffany A. Henderson; Patrick D. Vigil; Harry L. T. Mobley

2009-01-01

273

Occurrence of Escherichia coli in Wild Cottontail Rabbits.  

PubMed

Free-ranging cottontail rabbits (Sylvilagus floridanus) from two areas in central Pennsylvania were sampled over a 4-year period. Large numbers of coliforms were isolated from the intestinal tracts of these animals; in 136 of the 141 rabbits sampled, Escherichia coli was found to be a major component of the alimentary flora. Four serogroups (O7, O77, O73, and O103) were predominant among the isolates and were considered resistant coliflora of this species of cottontail rabbit. PMID:16345208

Kozlowski, R; Glantz, P J; Anthony, R G

1977-03-01

274

Functional requirements for heat induced genome amplification in Escherichia coli  

Microsoft Academic Search

A temperature shift-up induces extra rounds of fully replicated chromosomes in Escherichia coli and leads to an increase in DNA\\/mass ratio. In the present work we characterize the requirements for this heat-induced replication (HIR) with respect to replisome components, replication restart, and recombination functions. We found that HIR requires Klenow and 5?–3? exonuclease activities from Pol I and Pol III,

Rocío González-Soltero; Alfonso Jiménez-Sánchez; Emilia Botello

2008-01-01

275

Peroxidase activity of cytochrome bd from Escherichia coli  

Microsoft Academic Search

Cytochrome bd from Escherichia coli is able to oxidize such substrates as guaiacol, ferrocene, benzohydroquinone, and potassium ferrocyanide through the peroxidase\\u000a mechanism, while none of these donors is oxidized in the oxidase reaction (i.e. in the reaction that involves molecular oxygen\\u000a as the electron acceptor). Peroxidation of guaiacol has been studied in detail. The dependence of the rate of the

V. B. Borisov; A. I. Davletshin; A. A. Konstantinov

2010-01-01

276

Expression of fully functional tetrameric human hemoglobin in Escherichia coli  

Microsoft Academic Search

Synthesis genes encoding the human α- and β-globin polypeptides have been expressed from a single operon in Escherichia coli. The α- and β-globin polypeptides associate into soluble tetramers, incorporate heme, and accumulate to >5% of the total cellular protein. Purified recombinant hemoglobin has the correct stoichiometry of α- and β-globin chains and contains a full complement of heme. Each globin

S. J. Hoffman; D. L. Looker; J. M. Roehrich; P. E. Cozart; S. L. Durfee; J. L. Tedesco; G. L. Stetler

1990-01-01

277

Expression of Fully Functional Tetrameric Human Hemoglobin in Escherichia coli  

Microsoft Academic Search

Synthetic genes encoding the human alpha- and beta-globin polypeptides have been expressed from a single operon in Escherichia coli. The alpha- and beta-globin polypeptides associate into soluble tetramers, incorporate heme, and accumulate to >5% of the total cellular protein. Purified recombinant hemoglobin has the correct stoichiometry of alpha- and beta-globin chains and contains a full complement of heme. Each globin

Stephen J. Hoffman; Douglas L. Looker; Jeanne M. Roehrich; Paul E. Cozart; Steven L. Durfee; John L. Tedesco; Gary L. Stetler

1990-01-01

278

Genome sequence of enterohaemorrhagic Escherichia coli O157:H7  

Microsoft Academic Search

The bacterium Escherichia coli O157:H7 is a worldwide threat to public health and has been implicated in many outbreaks of haemorrhagic colitis, some of which included fatalities caused by haemolytic uraemic syndrome. Close to 75,000 cases of O157:H7 infection are now estimated to occur annually in the United States. The severity of disease, the lack of effective treatment and the

Nicole T. Perna; Guy Plunkett; Valerie Burland; Bob Mau; Jeremy D. Glasner; Debra J. Rose; George F. Mayhew; Peter S. Evans; Jason Gregor; Heather A. Kirkpatrick; György Pósfai; Jeremiah Hackett; Sara Klink; Adam Boutin; Ying Shao; Leslie Miller; Erik J. Grotbeck; N. Wayne Davis; Alex Lim; Eileen T. Dimalanta; Konstantinos D. Potamousis; Jennifer Apodaca; Thomas S. Anantharaman; Jieyi Lin; Galex Yen; David C. Schwartz; Rodney A. Welch; Frederick R. Blattner

2001-01-01

279

Recombinant expression of bioactive peptide lunasin in Escherichia coli  

Microsoft Academic Search

Lunasin, a cancer-preventive peptide, was isolated from soybean, barley, and wheat. Previous studies showed that this 43-amino\\u000a acid peptide has the ability to suppress chemical carcinogen-induced transformation in mammalian cells and skin carcinogenesis\\u000a in mice. In this study, we attempted to use the Escherichia coli T7 expression system for expression of lunasin. The lunasin gene was synthesized by overlapping extension

Chin-Feng Liu; Tzu-Ming Pan

2010-01-01

280

Lethal Effects of Electric Current on Escherichia coli  

PubMed Central

An attempt has been made to use low-voltage alternating current to kill microorganisms such as Escherichia coli. The bactericidal effect depends on the energy passing through the suspension and on the time during which the cells are left standing in the medium after the treatment. Most of the toxicity is due to an indirect effect developed with unalterable electrodes in the presence of chlorides in the medium. This method might be applied to eliminate pollution of natural waters. PMID:4909349

Pareilleux, A.; Sicard, N.

1970-01-01

281

Avian pathogenic Escherichia coli bind fibronectin and laminin  

Microsoft Academic Search

Avian colisepticemia frequently occurs after respiratory tract damage, the primary site for infection allows bacteria to encounter\\u000a an exposed basement membrane, where laminin and fibronectin are important components. We investigated the ability of an isolate\\u000a of avian pathogenic Escherichia coli to bind fibronectin and laminin. Using Far-western dot blot analysis, we demonstrated the ability of this microorganism to\\u000a bind basement

Rosa María Ramírez; Yolanda Almanza; Rafael González; Santos García; Norma Heredia

2009-01-01

282

Chemotaxis in Escherichia coli: Methylation of che Gene Products  

Microsoft Academic Search

The products of three chemotaxis-specific genes in Escherichia coli, cheM, cheD, and cheZ, are methylated. The cheZ gene codes for the synthesis of a 24,000 molecular weight polypeptide that appears in the cytoplasm. cheM codes for the synthesis of a membrane-bound polypeptide with a molecular weight of 61,000. cheD codes for another membrane-bound polypeptide with an apparent molecular weight of

Michael Silverman; Melvin Simon

1977-01-01

283

A second allosteric site in Escherichia coli aspartate transcarbamoylase.  

PubMed

Escherichia coli aspartate transcarbamoylase is feedback inhibited by CTP and UTP in the presence of CTP. Here, we show by X-ray crystallography that UTP binds to a unique site on each regulatory chain of the enzyme that is near but not overlapping with the known CTP site. These results bring into question all of the previously proposed mechanisms of allosteric regulation in aspartate transcarbamoylase. PMID:22667327

Peterson, Alexis W; Cockrell, Gregory M; Kantrowitz, Evan R

2012-06-19

284

Ozone-initiated disinfection kinetics of Escherichia coli in water  

Microsoft Academic Search

The effect of ozonation on the rate of disinfection of Escherichia coli was investigated as a function of ozone concentration, ozonation duration and flow rates. Ozone was generated in situ using Corona discharge method using compressed oxygen stream and depending on the oxygen flux the ozone concentrations ranged from 0.91–4.72 mg\\/L. The rate of disinfection of all the three microbes

Favourite Zuma; Johnson Lin; Sreekanth B. Jonnalagadda

2009-01-01

285

Biomolecular Mechanisms of Pseudomonas aeruginosa and Escherichia coli Biofilm Formation  

PubMed Central

Pseudomonas aeruginosa and Escherichia coli are the most prevalent Gram-negative biofilm forming medical device associated pathogens, particularly with respect to catheter associated urinary tract infections. In a similar manner to Gram-positive bacteria, Gram-negative biofilm formation is fundamentally determined by a series of steps outlined more fully in this review, namely adhesion, cellular aggregation, and the production of an extracellular polymeric matrix. More specifically this review will explore the biosynthesis and role of pili and flagella in Gram-negative adhesion and accumulation on surfaces in Pseudomonas aeruginosa and Escherichia coli. The process of biofilm maturation is compared and contrasted in both species, namely the production of the exopolysaccharides via the polysaccharide synthesis locus (Psl), pellicle Formation (Pel) and alginic acid synthesis in Pseudomonas aeruginosa, and UDP-4-amino-4-deoxy-l-arabinose and colonic acid synthesis in Escherichia coli. An emphasis is placed on the importance of the LuxR homologue sdiA; the luxS/autoinducer-II; an autoinducer-III/epinephrine/norepinephrine and indole mediated Quorum sensing systems in enabling Gram-negative bacteria to adapt to their environments. The majority of Gram-negative biofilms consist of polysaccharides of a simple sugar structure (either homo- or heteropolysaccharides) that provide an optimum environment for the survival and maturation of bacteria, allowing them to display increased resistance to antibiotics and predation.

Laverty, Garry; Gorman, Sean P.; Gilmore, Brendan F.

2014-01-01

286

Analysis of plasmids cloned from a virulent avian Escherichia coli and transformed into Escherichia coli DH5 alpha.  

PubMed

Three of four plasmids from a virulent wild-type avian Escherichia coli were cloned or transformed into an avirulent laboratory recipient E. coli DH5 alpha and tested for the ability to confer a virulence phenotype. The three plasmids transformed into E. coli DH5 alpha were 5, 6, and 56 kb. A fourth plasmid of 64 kb was not successfully transformed. Parameters used to measure virulence included presence of type 1 pili and a smooth lipopolysaccharide (LPS) layer, motility, production of Colicin V, resistance to host complement, and embryo lethality. The 5-kb plasmid encoded for ampicillin resistance, whereas the 6-kb plasmid encoded for tetracycline resistance. The 56-kb plasmid encoded for streptomycin, sulfisoxazole, and tetracycline resistance. Twelve-day embryos inoculated with 467 colony-forming units of E. coli DH5 alpha containing the 56-kb plasmid had increased death rates (45%) in the embryo lethality assay and a decreased weight of surviving embryos with cranial hemorrhages as compared with embryos inoculated with similar amounts of E. coli DH5 alpha (0%) and phosphate-buffered saline (0%). Embryos inoculated with the wild-type virulent E. coli had 90% deaths. The 56-kb plasmid also had homology with a probe for Colicin V production (cvaC). No differences in LPS layer, complement resistance, motility, Colicin V activity, type 1 pili, cell-free supernatant proteins, or outer membrane proteins were observed in the transformants when compared with nontransformed E. coli DH5 alpha. PMID:8883780

Wooley, R E; Gibbs, P S; Dickerson, H W; Brown, J; Nolan, L K

1996-01-01

287

Transduction of Escherichia coli by bacteriophage P1 in soil.  

PubMed Central

Transduction of Escherichia coli W3110(R702) and J53(RP4) (10(4) to 10(5) CFU/g of soil) by lysates of temperature-sensitive specialized transducing derivatives of bacteriophage P1 (10(4) to 10(5) PFU/g of soil) (P1 Cm cts, containing the resistance gene for chloramphenicol, or P1 Cm cts::Tn501, containing the resistance genes for chloramphenicol and mercury [Hg]) occurred in soil amended with montmorillonite or kaolinite and adjusted to a -33-kPa water tension. In nonsterile soil, survival of introduced E. coli and the numbers of E. coli transductants resistant to chloramphenicol or Hg were independent of the clay amendment. The numbers of added E. coli increased more when bacteria were added in Luria broth amended with Ca and Mg (LCB) than when they were added in saline, and E. coli transductants were approximately 1 order of magnitude higher in LCB; however, the same proportion of E. coli was transduced with both types of inoculum. In sterile soil, total and transduced E. coli and P1 increased by 3 to 4 logs, which was followed by a plateau when they were inoculated in LCB and a gradual decrease when they were inoculated in saline. Transduction appeared to occur primarily in the first few days after addition of P1 to soil. The transfer of Hg or chloramphenicol resistance from lysogenic to nonlysogenic E. coli by phage P1 occurred in both sterile and nonsterile soils. On the basis of heat-induced lysis and phenotype, as well as hybridization with a DNA probe in some studies, the transductants appeared to be the E. coli that was added. Transduction of indigenous soil bacteria was not unequivocally demonstrated.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3046491

Zeph, L R; Onaga, M A; Stotzky, G

1988-01-01

288

Fluorogenic assays for immediate confirmation of Escherichia coli.  

PubMed Central

Rapid assays for Escherichia coli were developed by using the compound 4-methylumbelliferone glucuronide (MUG), which is hydrolyzed by glucuronidase to yield a fluorogenic product. The production of glucuronidase was limited to strains of E. coli and some Salmonella and Shigella strains in the family Enterobacteriaceae. For immediate confirmation of the presence of E. coli in most-probable-number tubes, MUG was incorporated into lauryl tryptose broth at a final concentration of 100 micrograms/ml. Results of both the presumptive test (gas production) and the confirmed test (fluorescence) for E. coli were obtained from a variety of food, water, and milk samples after incubation for only 24 h at 35 degrees C. Approximately 90% of the tubes showing both gas production and fluorescence contained fecal coliforms (they were positive in EC broth incubated at 45 degrees C). Few false-positive reactions were observed. The lauryl tryptose broth-MUG-most-probable-number assay was superior to violet red bile agar for the detection of heat- and chlorine-injured E. coli cells. Anaerogenic strains produced positive reactions, and small numbers of E. coli could be detected in the presence of large numbers of competing bacteria. The fluorogenic assay was sensitive and rapid; the presence of one viable cell was detected within 20 h. E. coli colonies could be distinguished from other coliforms on membrane filters and plates of violet red bile agar if MUG was incorporated into the culture media. A rapid confirmatory test for E. coli that is amenable to automation was developed by using microtitration plates filled with a nonselective medium containing MUG. Pure or mixed cultures containing E. coli produced fluorescence within 4 h (most strains) to 24 h (a few weakly positive strains). Images PMID:7049088

Feng, P C; Hartman, P A

1982-01-01

289

Identification of Escherichia coli Genes Associated with Urinary Tract Infections  

PubMed Central

Escherichia coli is the most common cause of urinary tract infections (UTIs). E. coli genes epidemiologically associated with UTIs are potentially valuable in developing strategies for treating and/or preventing such infections as well as differentiating uropathogenic E. coli from nonuropathogenic E. coli. To identify E. coli genes associated with UTIs in humans, we combined microarray-based and PCR-based analyses to investigate different E. coli source groups derived from feces of healthy humans and from patients with cystitis, pyelonephritis, or urosepsis. The cjrABC-senB gene cluster, sivH, sisA, sisB, eco274, and fbpB, were identified to be associated with UTIs. Of these, cjrABC-senB, sisA, sisB, and fbpB are known to be involved in urovirulence in the mouse model of ascending UTI. Our results provide evidence to support their roles as urovirulence factors in human UTIs. In addition, the newly identified UTI-associated genes were mainly found in members of phylogenetic groups B2 and/or D. PMID:22075599

Mao, Bin-Hsu; Chang, Yung-Fu; Scaria, Joy; Chang, Chih-Ching; Chou, Li-Wei; Tien, Ni; Wu, Jiunn-Jong; Tseng, Chin-Chung; Wang, Ming-Cheng; Chang, Chao-Chin; Hsu, Yuan-Man

2012-01-01

290

Chapter 8 Isolation and Identification of Escherichia coli  

E-print Network

Isolation and identification of Escherichia coli serotype O157:H7 can be greatly enhanced when optimal laboratory media and techniques are employed. The methods presented here are intended to be economical and to offer laboratorians some flexibility in choice of protocol and media. Laboratories that do not have sufficient resources to adopt the methods described below should consider sending specimens or isolates to other laboratory facilities that routinely perform these procedures. Laboratory supplies required for diagnosis of E. coli O157:H7 are listed in Annex H. A. Isolation and Identification Methods E. coli O157:H7 rapidly ferments lactose and is indistinguishable from most other E. coli serotypes on traditional lactose-containing media. However, unlike approximately 80 % of other E. coli, nearly all isolates of E. coli O157:H7 ferment D-sorbitol slowly, or not at all. Sorbitol-MacConkey (SMAC) agar was developed to take advantage of this characteristic by substituting the carbohydrate sorbitol for lactose in MacConkey agar, and it is the medium of choice for

unknown authors

291

Direct transmission of Escherichia coli from poultry to humans.  

PubMed Central

Eight hundred and sixty-four Escherichia coli isolates from workers at the University of Ibadan Teaching and Research Poultry Farm, and 216 isolates from poultry attendants at a commercial poultry farm in the city were found to be resistant to streptomycin, sulphafurazole and tetracycline. In contrast, all 576 and 288 E. coli isolates from village fowls and from villagers respectively were sensitive to these drugs. Isolates from birds in a modern university poultry unit (3744) exhibited the same resistance patterns as those isolated from workers who were in direct contact with the birds. No nalidixic acid-resistant E. coli was isolated from farm workers prior to their assignment to the experimental pen. Following experimental oral infection of birds with E. coli K12 J5 NA+ Lac-, the organism was recovered from the workers who manned the experimental pen. Neither before nor after the experimental infection was any nalidixic acid-resistant E. coli isolated from workers who manned the pen from which birds used in the experiment were selected. Similarly, no drug resistant organisms were isolated from workers outside the poultry unit of the university or commercial farm. The MIC of the drugs against the avian and human E. coli isolates at the university and commercial poultry farms were similar. PMID:2691268

Ojeniyi, A. A.

1989-01-01

292

Escherichia coli Isolated from Domestic Animals Pathogenic for Gnotobiotic Piglets.  

PubMed

Three strains of Escherichia coli isolated from infectious processes in a calf, a dog, and a cat were examined for their capacity to produce disease or death, or both, in newborn gnotobiotic piglets. The O groups represented by these particular strains of E. coli were O4: (canine origin), O6: (feline origin), and O39: (bovine origin). All three isolates upon oral administration proved to be pathogenic. Infection with the E. coli O4: (canine) or O39: (bovine) consistently produced signs of enteric coli-bacillosis and death in all 1- and 3-day-old piglets within 24 to 48 hr. The O6: (feline) isolate, on the other hand, produced a marked polyserositis and generally required 6 to 7 days to kill a piglet. Only the respective type of E. coli used in the particular trial was recovered from the diseased piglets. These findings suggest the possible role of domestic animals and household pets in the spread of potentially pathogenic E. coli to other species. PMID:16558047

Meyer, R C; Rhoades, H E; Saxena, S P; Simon, J

1971-06-01

293

Escherichia coli sequence type 131: epidemiology and challenges in treatment.  

PubMed

Escherichia coli ST131 has emerged as a global epidemic, multidrug-resistant clone of E. coli causing extra-intestinal infections. It is now highly prevalent among fluoroquinolone-resistant and CTX-M ESBL-producing E. coli isolates worldwide. Humans are likely the primary reservoir of ST131. Factors associated with its acquisition include residence in long-term care facilities and recent receipt of antimicrobial agents. E. coli ST131 causes a wide array of infections ranging from cystitis to life-threatening sepsis. Fluoroquinolones and trimethoprim-sulfamethoxazole are no longer adequate options for empiric therapy when E. coli ST131 is suspected from risk factors and local epidemiology. Expanded-spectrum cephalosporins, piperacillin-tazobactam and carbapenems are options to treat serious non-ESBL-producing E. coli ST131 infections, while carbapenems are indicated for ESBL-producing infections. There is a growing interest in reevaluating oral agents including fosfomycin and pivmecillinam for less serious infections such as uncomplicated cystitis. PMID:24694052

Qureshi, Zubair A; Doi, Yohei

2014-05-01

294

[Escherichia coli, a pathogen under fire from the news].  

PubMed

Escherichia coli is both a gastrointestinal tract commensal and a major pathogen. In recent years, E. coli is under fire from the news due to a better understanding of pathogenic factors, outbreaks of infections caused by enterohaemorrhagic strains, and last but not least, the worrying development of antibiotic resistance. Due to the absence of new compounds active against these strains, producing extended-spectrum ß-lactamases (ESBL) and frequently multiresistant to other antibiotics, their emergence will pose therapeutic problems for practitioners of all pediatric specialties. The gold standard treatment for severe infections due to ESBL-E. coli family is the penem class. The frequent use of penems promotes the emergence of strains resistant to carbapenems. Sparing carbapenems should be a clear objective for non life-threatening infections. PMID:23178139

Cohen, R; Raymond, J; Gendrel, D; Bingen, E

2012-11-01

295

Inhibition of injured Escherichia coli by several selective agents.  

PubMed

A population of Escherichia coli ML30 cells was exposed to a quaternary ammonium compound, and injury to the cells was measured by a comparison of counts on Trypticase Soy Agar and Violet Red Bile Agar. Substantial injury could not be detected with a minimal medium. The ingredients of Violet Red Bile Agar were tested against damaged cells. The bile salts mixture alone in the medium prevented as many injured cells from growing as did any combination of the selective agents and inhibited as many injured bacteria as were inhibited by Violet Red Bile Agar itself. These dyes and salts were similarly assayed in minimal agar, and comparable results were obtained. Individual bile salts and other potential selective agents were added to the minimal medium, and the media were tested for inhibition of injured E. coli. Sodium deoxycholate was the bile salt most inhibitory to damaged E. coli cells. PMID:4924998

Scheusner, D L; Busta, F F; Speck, M L

1971-01-01

296

Engineering Escherichia coli K12 MG1655 to use starch  

PubMed Central

Background To attain a sustainable bioeconomy, fuel, or valuable product, production must use biomass as substrate. Starch is one of the most abundant biomass resources and is present as waste or as a food and agroindustry by-product. Unfortunately, Escherichia coli, one of the most widely used microorganisms in biotechnological processes, cannot use starch as a carbon source. Results We engineered an E. coli strain capable of using starch as a substrate. The genetic design employed the native capability of the bacterium to use maltodextrins as a carbon source plus expression and secretion of its endogenous ?-amylase, AmyA, in an adapted background. Biomass production improved using 35% dissolved oxygen and pH 7.2 in a controlled bioreactor. Conclusion The engineered E. coli strain can use starch from the milieu and open the possibility of optimize the process to use agroindustrial wastes to produce biofuels and other valuable chemicals. PMID:24886307

2014-01-01

297

???????????????????????????????????????????????????????????????? Escherichia coli ????????????????????????? ISOLATION AND SCREENING OF LACTIC ACID BACTERIA CAPABLE OF INHIBITING GROWTH OF SOME ESCHERICHIA COLI ISOLATED FROM SWINE  

Microsoft Academic Search

One hundred and forty-seven strains of lactic acid bacteria (LAB) were isolated from some soils, fermented foods, vegetables, fruits, milk and animal products. After cultivation in MRS broth at 37 ?C for 96 hours, each culture supernatant was evaluated its growth inhibitory activity by using a paper disc diffusion method against one strain of Escherichia coli O157:H7 and nine strains

Mongkhon Punyarat; Narumol Thongwai

298

ESCHERICHIA COLI ISOLATED FROM CALVES WITH DIARRHŒA: MANNOSE-RESISTANT HAEMAGGLUTINATION  

E-print Network

ESCHERICHIA COLI ISOLATED FROM CALVES WITH DIARRHŒA: MANNOSE-RESISTANT HAEMAGGLUTINATION souches de Escherichia coli isolées des veaux diarrhéiques. La détection de l'antigène K99, en 84 souches de Escherichia coli, a été effectuée par le Brush-Border, l'hémagglutination avec et sans mannose et

Paris-Sud XI, Université de

299

Domain Bridging Interactions in the Allosteric Network for IIAGlc Inhibition of the Escherichia coli Glycerol Kinase  

E-print Network

DOMAIN BRIDGING INTERACTIONS IN THE ALLOSTERIC NETWORK FOR IIAGLC INHIBITION OF THE ESCHERICHIA COLI GLYCEROL KINASE A Thesis by EDITH ABENA ACQUAYE Submitted to the Office of Graduate Studies of Texas A&M University... of the Escherichia coli Glycerol Kinase Copyright 2010 Edith Abena Acquaye DOMAIN BRIDGING INTERACTIONS IN THE ALLOSTERIC NETWORK FOR IIAGLC INHIBITION OF THE ESCHERICHIA COLI GLYCEROL KINASE A Thesis by EDITH ABENA ACQUAYE Submitted...

Acquaye, Edith Abena

2011-10-21

300

Global dissemination of a multidrug resistant Escherichia coli clone  

PubMed Central

Escherichia coli sequence type 131 (ST131) is a globally disseminated, multidrug resistant (MDR) clone responsible for a high proportion of urinary tract and bloodstream infections. The rapid emergence and successful spread of E. coli ST131 is strongly associated with several factors, including resistance to fluoroquinolones, high virulence gene content, the possession of the type 1 fimbriae FimH30 allele, and the production of the CTX-M-15 extended spectrum ?-lactamase (ESBL). Here, we used genome sequencing to examine the molecular epidemiology of a collection of E. coli ST131 strains isolated from six distinct geographical locations across the world spanning 2000–2011. The global phylogeny of E. coli ST131, determined from whole-genome sequence data, revealed a single lineage of E. coli ST131 distinct from other extraintestinal E. coli strains within the B2 phylogroup. Three closely related E. coli ST131 sublineages were identified, with little association to geographic origin. The majority of single-nucleotide variants associated with each of the sublineages were due to recombination in regions adjacent to mobile genetic elements (MGEs). The most prevalent sublineage of ST131 strains was characterized by fluoroquinolone resistance, and a distinct virulence factor and MGE profile. Four different variants of the CTX-M ESBL–resistance gene were identified in our ST131 strains, with acquisition of CTX-M-15 representing a defining feature of a discrete but geographically dispersed ST131 sublineage. This study confirms the global dispersal of a single E. coli ST131 clone and demonstrates the role of MGEs and recombination in the evolution of this important MDR pathogen. PMID:24706808

Petty, Nicola K.; Ben Zakour, Nouri L.; Stanton-Cook, Mitchell; Skippington, Elizabeth; Totsika, Makrina; Forde, Brian M.; Phan, Minh-Duy; Gomes Moriel, Danilo; Peters, Kate M.; Davies, Mark; Rogers, Benjamin A.; Dougan, Gordon; Rodriguez-Bano, Jesus; Pascual, Alvaro; Pitout, Johann D. D.; Upton, Mathew; Paterson, David L.; Walsh, Timothy R.; Schembri, Mark A.; Beatson, Scott A.

2014-01-01

301

Plasmid replicon typing of commensal and pathogenic Escherichia coli isolates.  

PubMed

Despite the critical role of plasmids in horizontal gene transfer, few studies have characterized plasmid relatedness among different bacterial populations. Recently, a multiplex PCR replicon typing protocol was developed for classification of plasmids occurring in members of the Enterobacteriaceae. Here, a simplified version of this replicon typing procedure which requires only three multiplex panels to identify 18 plasmid replicons is described. This method was used to screen 1,015 Escherichia coli isolates of avian, human, and poultry meat origin for plasmid replicon types. Additionally, the isolates were assessed for their content of several colicin-associated genes. Overall, a high degree of plasmid variability was observed, with 221 different profiles occurring among the 1,015 isolates examined. IncFIB plasmids were the most common type identified, regardless of the source type of E. coli. IncFIB plasmids occurred significantly more often in avian pathogenic E. coli (APEC) and retail poultry E. coli (RPEC) than in uropathogenic E. coli (UPEC) and avian and human fecal commensal E. coli isolates (AFEC and HFEC, respectively). APEC and RPEC were also significantly more likely than UPEC, HFEC, and AFEC to possess the colicin-associated genes cvaC, cbi, and/or cma in conjunction with one or more plasmid replicons. The results suggest that E. coli isolates contaminating retail poultry are notably similar to APEC with regard to plasmid profiles, with both generally containing multiple plasmid replicon types in conjunction with colicin-related genes. In contrast, UPEC and human and avian commensal E. coli isolates generally lack the plasmid replicons and colicin-related genes seen in APEC and RPEC, suggesting limited dissemination of such plasmids among these bacterial populations. PMID:17277222

Johnson, Timothy J; Wannemuehler, Yvonne M; Johnson, Sara J; Logue, Catherine M; White, David G; Doetkott, Curt; Nolan, Lisa K

2007-03-01

302

Plasmid Replicon Typing of Commensal and Pathogenic Escherichia coli Isolates?  

PubMed Central

Despite the critical role of plasmids in horizontal gene transfer, few studies have characterized plasmid relatedness among different bacterial populations. Recently, a multiplex PCR replicon typing protocol was developed for classification of plasmids occurring in members of the Enterobacteriaceae. Here, a simplified version of this replicon typing procedure which requires only three multiplex panels to identify 18 plasmid replicons is described. This method was used to screen 1,015 Escherichia coli isolates of avian, human, and poultry meat origin for plasmid replicon types. Additionally, the isolates were assessed for their content of several colicin-associated genes. Overall, a high degree of plasmid variability was observed, with 221 different profiles occurring among the 1,015 isolates examined. IncFIB plasmids were the most common type identified, regardless of the source type of E. coli. IncFIB plasmids occurred significantly more often in avian pathogenic E. coli (APEC) and retail poultry E. coli (RPEC) than in uropathogenic E. coli (UPEC) and avian and human fecal commensal E. coli isolates (AFEC and HFEC, respectively). APEC and RPEC were also significantly more likely than UPEC, HFEC, and AFEC to possess the colicin-associated genes cvaC, cbi, and/or cma in conjunction with one or more plasmid replicons. The results suggest that E. coli isolates contaminating retail poultry are notably similar to APEC with regard to plasmid profiles, with both generally containing multiple plasmid replicon types in conjunction with colicin-related genes. In contrast, UPEC and human and avian commensal E. coli isolates generally lack the plasmid replicons and colicin-related genes seen in APEC and RPEC, suggesting limited dissemination of such plasmids among these bacterial populations. PMID:17277222

Johnson, Timothy J.; Wannemuehler, Yvonne M.; Johnson, Sara J.; Logue, Catherine M.; White, David G.; Doetkott, Curt; Nolan, Lisa K.

2007-01-01

303

Discovery of Escherichia coli methionyl-tRNA synthetase mutants for efficient labeling of proteins  

E-print Network

Discovery of Escherichia coli methionyl-tRNA synthetase mutants for efficient labeling of proteins with mutant forms of MetRS. Link and coworkers recently reported a high-throughput screen for E. coli Met

Goddard III, William A.

304

Autoinducer 2-based quorum sensing response of Escherichia coli to sub-therapeutic tetracycline exposure  

E-print Network

-therapeutic tetracycline, the expression of genes associated with the conjugal transfer of antibiotic resistance plasmids, and the conjugal transfer of these plasmids in Escherichia coli. The studies showed that AI-2 activity increased in Tets E. coli in the presence...

Lu, Lingeng

2006-10-30

305

THE WIDESPREAD OCCURRENCE OF THE ENTEROHEMOLYSIN GENE EHLYA AMONG ENVIRONMENTAL STRAINS OF ESCHERICHIA COLI  

EPA Science Inventory

The putative virulence factor enterohemolysin, encoded for by the ehlyA gene, has been closely associated with the pathogenic enterohemorrhagic Escherichia coli (EHEC) group. E. coli isolates from effluents from seven geographically dispersed municipal ...

306

Salmonella typhimurium intercepts Escherichia coli signaling to enhance antibiotic tolerance  

PubMed Central

Bacterial communication plays an important role in many population-based phenotypes and interspecies interactions, including those in host environments. These interspecies interactions may prove critical to some infectious diseases, and it follows that communication between pathogenic bacteria and commensal bacteria is a subject of growing interest. Recent studies have shown that Escherichia coli uses the signaling molecule indole to increase antibiotic tolerance throughout its population. Here, we show that the intestinal pathogen Salmonella typhimurium increases its antibiotic tolerance in response to indole, even though S. typhimurium does not natively produce indole. Increased antibiotic tolerance can be induced in S. typhimurium by both exogenous indole added to clonal S. typhimurium populations and indole produced by E. coli in mixed-microbial communities. Our data show that indole-induced tolerance in S. typhimurium is mediated primarily by the oxidative stress response and, to a lesser extent, by the phage shock response, which were previously shown to mediate indole-induced tolerance in E. coli. Further, we find that indole signaling by E. coli induces S. typhimurium antibiotic tolerance in a Caenorhabditis elegans model for gastrointestinal infection. These results suggest that the intestinal pathogen S. typhimurium can intercept indole signaling from the commensal bacterium E. coli to enhance its antibiotic tolerance in the host intestine. PMID:23946425

Vega, Nicole M.; Allison, Kyle R.; Samuels, Amanda N.; Klempner, Mark S.; Collins, James J.

2013-01-01

307

The genetic basis of Escherichia coli pathoadaptation to macrophages.  

PubMed

Antagonistic interactions are likely important driving forces of the evolutionary process underlying bacterial genome complexity and diversity. We hypothesized that the ability of evolved bacteria to escape specific components of host innate immunity, such as phagocytosis and killing by macrophages (M?), is a critical trait relevant in the acquisition of bacterial virulence. Here, we used a combination of experimental evolution, phenotypic characterization, genome sequencing and mathematical modeling to address how fast, and through how many adaptive steps, a commensal Escherichia coli (E. coli) acquire this virulence trait. We show that when maintained in vitro under the selective pressure of host M? commensal E. coli can evolve, in less than 500 generations, virulent clones that escape phagocytosis and M? killing in vitro, while increasing their pathogenicity in vivo, as assessed in mice. This pathoadaptive process is driven by a mechanism involving the insertion of a single transposable element into the promoter region of the E. coli yrfF gene. Moreover, transposition of the IS186 element into the promoter of Lon gene, encoding an ATP-dependent serine protease, is likely to accelerate this pathoadaptive process. Competition between clones carrying distinct beneficial mutations dominates the dynamics of the pathoadaptive process, as suggested from a mathematical model, which reproduces the observed experimental dynamics of E. coli evolution towards virulence. In conclusion, we reveal a molecular mechanism explaining how a specific component of host innate immunity can modulate microbial evolution towards pathogenicity. PMID:24348252

Miskinyte, Migla; Sousa, Ana; Ramiro, Ricardo S; de Sousa, Jorge A Moura; Kotlinowski, Jerzy; Caramalho, Iris; Magalhães, Sara; Soares, Miguel P; Gordo, Isabel

2013-01-01

308

The Escherichia coli Proteome: Past, Present, and Future Prospects†  

PubMed Central

Proteomics has emerged as an indispensable methodology for large-scale protein analysis in functional genomics. The Escherichia coli proteome has been extensively studied and is well defined in terms of biochemical, biological, and biotechnological data. Even before the entire E. coli proteome was fully elucidated, the largest available data set had been integrated to decipher regulatory circuits and metabolic pathways, providing valuable insights into global cellular physiology and the development of metabolic and cellular engineering strategies. With the recent advent of advanced proteomic technologies, the E. coli proteome has been used for the validation of new technologies and methodologies such as sample prefractionation, protein enrichment, two-dimensional gel electrophoresis, protein detection, mass spectrometry (MS), combinatorial assays with n-dimensional chromatographies and MS, and image analysis software. These important technologies will not only provide a great amount of additional information on the E. coli proteome but also synergistically contribute to other proteomic studies. Here, we review the past development and current status of E. coli proteome research in terms of its biological, biotechnological, and methodological significance and suggest future prospects. PMID:16760308

Han, Mee-Jung; Lee, Sang Yup

2006-01-01

309

Nonthermal atmospheric argon plasma jet effects on Escherichia coli biomacromolecules.  

PubMed

Nonthermal atmospheric plasma jet, a promising technology based on ionized gas at low temperatures, can be applied for disinfection of contaminated surfaces. In this study, Escherichia coli cells and their macromolecules were exposed to the nonthermal atmospheric argon plasma jet for different time durations. Total protein, genomic DNA, and malondialdehyde (MDA) levels of E. coli were assessed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and silver staining; agarose gel electrophoresis; and measurement of absorbance at 534 nm, respectively. After exposure, the spectroscopic results of liquid samples indicated that the survival reduction of E. coli can reach to 100 % in an exposure time of 600 s. Moreover, inactivation zones of E. coli, DNA degradation, and MDA levels were significantly increased. Additionally, banding patterns of total protein were changed and amino acid concentrations increased following ninhydrin test. The experimental results suggest that the nonthermal plasma could serve as an effective instrument for both sterilizing E. coli and degrading macromolecules from the surface of the objects being sterilized. PMID:23982422

Hosseinzadeh Colagar, Abasalt; Memariani, Hamed; Sohbatzadeh, Farshad; Valinataj Omran, Azadeh

2013-12-01

310

Recent Advances in Understanding Enteric Pathogenic Escherichia coli  

PubMed Central

SUMMARY Although Escherichia coli can be an innocuous resident of the gastrointestinal tract, it also has the pathogenic capacity to cause significant diarrheal and extraintestinal diseases. Pathogenic variants of E. coli (pathovars or pathotypes) cause much morbidity and mortality worldwide. Consequently, pathogenic E. coli is widely studied in humans, animals, food, and the environment. While there are many common features that these pathotypes employ to colonize the intestinal mucosa and cause disease, the course, onset, and complications vary significantly. Outbreaks are common in developed and developing countries, and they sometimes have fatal consequences. Many of these pathotypes are a major public health concern as they have low infectious doses and are transmitted through ubiquitous mediums, including food and water. The seriousness of pathogenic E. coli is exemplified by dedicated national and international surveillance programs that monitor and track outbreaks; unfortunately, this surveillance is often lacking in developing countries. While not all pathotypes carry the same public health profile, they all carry an enormous potential to cause disease and continue to present challenges to human health. This comprehensive review highlights recent advances in our understanding of the intestinal pathotypes of E. coli. PMID:24092857

Croxen, Matthew A.; Law, Robyn J.; Scholz, Roland; Keeney, Kristie M.; Wlodarska, Marta

2013-01-01

311

Glucosylation of Isoflavonoids in Engineered Escherichia coli  

PubMed Central

A glycosyltransferase, YjiC, from Bacillus licheniformis has been used for the modification of the commercially available isoflavonoids genistein, daidzein, biochanin A and formononetin. The in vitro glycosylation reaction, using UDP-?-D-glucose as a donor for the glucose moiety and aforementioned four acceptor molecules, showed the prominent glycosylation at 4? and 7 hydroxyl groups, but not at the 5th hydroxyl group of the A-ring, resulting in the production of genistein 4?-O-?-D-glucoside, genistein 7-O-?-D-glucoside (genistin), genistein 4?,7-O-?-D-diglucoside, biochanin A-7-O-?-D-glucoside (sissotrin), daidzein 4?-O-?-D-glucoside, daidzein 7-O-?-D-glucoside (daidzin), daidzein 4?, 7-O-?-D-diglucoside, and formononetin 7-O-?-D-glucoside (ononin). The structures of all the products were elucidated using high performance liquid chromatography-photo diode array and high resolution quadrupole time-of-flight electrospray ionization mass spectrometry (HR QTOFESI/MS) analysis, and were compared with commercially available standard compounds. Significantly higher bioconversion rates of all four isoflavonoids was observed in both in vitro as well as in vivo bioconversion reactions. The in vivo fermentation of the isoflavonoids by applying engineered E. coli BL21(DE3)/?pgi?zwf?ushA overexpressing phosphoglucomutase (pgm) and glucose 1-phosphate uridyltransferase (galU), along with YjiC, found more than 60% average conversion of 200 ?M of supplemented isoflavonoids, without any additional UDP-?-D-glucose added in fermentation medium, which could be very beneficial to large scale industrial production of isoflavonoid glucosides. PMID:24599002

Pandey, Ramesh Prasad; Parajuli, Prakash; Koirala, Niranjan; Lee, Joo Ho; Park, Yong Il; Sohng, Jae Kyung

2014-01-01

312

FRQUENCE DU ROTAVIRUS ET DE L'ASSOCIATION ROTAVIRUS ET ESCHERICHIA COLI K99+  

E-print Network

FR�QUENCE DU ROTAVIRUS ET DE L'ASSOCIATION ROTAVIRUS ET ESCHERICHIA COLI K99+ CHEZ DES VEAUX DE Escherichia coli (E. coli) porteurs de l'antigène K99', chez les veaux atteints de diarrhées néo- natales. coli K99' is found in 5 % of sick animals less than 10 days old. La mise en évidence par microscopie

Boyer, Edmond

313

Killing of Escherichia coli by human polymorphonuclear leucocytes in the presence of Bacteroides fragilis  

Microsoft Academic Search

The inhibitory effect of Bacteroides fragilis on the in vitro killing of Escherichia coli by polymorphonuclear leucocytes was studied with two pairs of E coli and B fragilis isolated from human wound infections. Both B fragilis strains behaved similarly: they inhibited the killing of one E coli strain, while the killing of the other E coli strain was not affected.

W A Vel; F Namavar; A M Verweij-van Vught; A N Pubben; D M MacLaren

1985-01-01

314

Influence of urinary constituents on the adherence of Escherichia coli to human uroepithelial cells in vitro  

Microsoft Academic Search

To study the influence of some urinary constituents on the adhesion ability of Escherichia coli to uroepithelial cells, a standard piliated strain (E. coli 31-B), its mutant lacking in type I pili (E. coli BH-5), and a wild-type laboratory E. coli isolate of serotype 04 possessing both MR and MS pili were used. The average number of bacteria adhering per

Vinod Kumar; Rajeshwar Sharma; Sanjay Chhibber; Kusum Harjai; Saroj Sharma

1997-01-01

315

FRQUENCE DES PILI FY ET K99 PARMI DES SOUCHES DE ESCHERICHIA COLI  

E-print Network

FRÃ?QUENCE DES PILI FY ET K99 PARMI DES SOUCHES DE ESCHERICHIA COLI ISOLÃ?ES DE VEAUX DIARRHÃ?IQUES EN IN FRANCE. - Epidemiological study of bovine E. coli shows that the FY E. coli pilus which has previously, eight of them carrying both FY and K99 pili. The K99 E. coli pilus is present in 86 fecal samples

Boyer, Edmond

316

INFECTION WITH ENTEROTOXIGENIC ESCHERICHIA COLI IN CALVES AND PROTECTION OF THE CALVES  

E-print Network

factors. The microorganisms most commonly incriminated are Escherichia coli (E. coli), rotavirus, coronavirus, and Cryptosporidium. Infection with E. coli in calves manifests itself in at least two different syndromes (Smith and Halls, 1968). One of these is E. coli septicaemia, which occurs in the first week

Paris-Sud XI, Université de

317

The Crystal Structure of the Escherichia coli RNase E Apoprotein and a Mechanism for  

E-print Network

Structure Article The Crystal Structure of the Escherichia coli RNase E Apoprotein and a Mechanism of structured RNA precursors in Escheri- chia coli. Here, we present the crystal structure of the E. coli RNase- radation of most mRNA in E. coli (Mudd et al., 1990; Babitzke and Kushner, 1991). In addition to its purely

Scott, William

318

Role of Enteroaggregative Escherichia coli Virulence Factors in Uropathogenesis  

PubMed Central

A multiresistant clonal Escherichia coli O78:H10 strain qualifying molecularly as enteroaggregative Escherichia coli (EAEC) was recently shown to be the cause of a community-acquired outbreak of urinary tract infection (UTI) in greater Copenhagen, Denmark, in 1991. This marks the first time EAEC has been associated with an extraintestinal disease outbreak. Importantly, the outbreak isolates were recovered from the urine of patients with symptomatic UTI, strongly implying urovirulence. Here, we sought to determine the uropathogenic properties of the Copenhagen outbreak strain and whether these properties are conferred by the EAEC-specific virulence factors. We demonstrated that through expression of aggregative adherence fimbriae, the principal adhesins of EAEC, the outbreak strain exhibited pronouncedly increased adherence to human bladder epithelial cells compared to prototype uropathogenic strains. Moreover, the strain was able to produce distinct biofilms on abiotic surfaces, including urethral catheters. These findings suggest that EAEC-specific virulence factors increase uropathogenicity and may have played a significant role in the ability of the strain to cause a community-acquired outbreak of UTI. Thus, inclusion of EAEC-specific virulence factors is warranted in future detection and characterization of uropathogenic E. coli. PMID:23357383

Boll, Erik J.; Struve, Carsten; Boisen, Nadia; Olesen, Bente; Stahlhut, Steen G.

2013-01-01

319

MECHANISM OF ACTION OF NALIDIXIC ACID ON ESCHERICHIA COLI  

PubMed Central

Goss, William A. (Sterling-Winthrop Research Institute, Rensselaer, N.Y.), William H. Dietz, and Thomas M. Cook. Mechanism of action of nalidixic acid on Escherichia coli. J. Bacteriol. 88:1112–1118. 1964.—Nalidixic acid was lethal for proliferating cultures of Escherichia coli. Associated with this lethal effect was the formation of elongated, serpentine forms. Cultures treated with nalidixic acid were osmotically stable; lethality was observed in the presence of stabilizers. Although it was possible to demonstrate leakage of intracellular components from treated cells, this effect occurred only after 99% of the cells were nonviable. Nalidixic acid had little or no effect on respiration with glucose as substrate. If cellular growth was restricted by suboptimal temperature or nutritional deficiencies, the drug was not lethal. Chemical analysis of cellular constituents revealed that lipid, protein, and ribonucleic acid levels were of the same order of magnitude in control and drug-treated cells. Only deoxyribonucleic acid (DNA) levels were markedly lowered in drug-treated cells. These facts are consistent with the view that nalidixic acid interferes with the synthesis of E. coli DNA. Images PMID:14219026

Goss, William A.; Deitz, William H.; Cook, Thomas M.

1964-01-01

320

Distribution of Core Oligosaccharide Types in Lipopolysaccharides from Escherichia coli  

PubMed Central

In the lipopolysaccharides of Escherichia coli there are five distinct core oligosaccharide (core OS) structures, designated K-12 and R1 to R4. The objective of this work was to determine the prevalences of these core OS types within the species. Unique sequences in the waa (core OS biosynthesis) gene operon were used to develop a PCR-based system that facilitated unequivocal determination of the core OS types in isolates of E. coli. This system was applied to the 72 isolates in the E. coli ECOR collection, a compilation of isolates that is considered to be broadly representative of the genetic diversity of the species. Fifty (69.4%) of the ECOR isolates contained the R1 core OS, 8 (11.1%) were representatives of R2, 8 (11.1%) were R3, 2 (2.8%) were R4, and only 4 (5.6%) were K-12. R1 is the only core OS type found in all four major phylogenetic groups (A, B1, B2, and D) in the ECOR collection. Virulent extraintestinal pathogenic E. coli isolates tend to be closely related to group B2 and, to a lesser extent, group D isolates. All of the ECOR representatives from the B2 and D groups had the R1 core OS. In contrast, commensal E. coli isolates are more closely related to group A, which contains isolates representing each of the five core OS structures. R3 was the only core OS type found in 38 verotoxigenic E. coli (VTEC) isolates from humans and cattle belonging to the common enterohemorrhagic E. coli serogroups O157, O111, and O26. Although isolates from other VTEC serogroups showed more core OS diversity, the R3 type (83.1% of all VTEC isolates) was still predominant. When non-VTEC commensal isolates from cattle were analyzed, it was found that most possessed the R1 core OS type. PMID:10678915

Amor, Karen; Heinrichs, David E.; Frirdich, Emilisa; Ziebell, Kim; Johnson, Roger P.; Whitfield, Chris

2000-01-01

321

Widespread antibiotic resistance of diarrheagenic Escherichia coli and Shigella species  

PubMed Central

Background: Antibiotic resistance of enteric pathogens particularly Shigella species, is a critical world-wide problem and monitoring their resistant pattern is essential, because the choice of antibiotics is absolutely dependent on regional antibiotic susceptibility patterns. During summer 2013, an unusual increase in number of diarrheal diseases was noticed in Isfahan, a central province of Iran. Therefore, the antibiotic resistance of diarrheagenic Escherichia coli and Shigella species isolated were evaluated. Materials and Methods: According to the guideline on National Surveillance System for Foodborn Diseases, random samples from patients with acute diarrhea were examined in local laboratories of health centers and samples suspicious of Shigella spp. were further assessed in referral laboratory. Isolated pathogens were identified by standard biochemical and serologic tests and antibiotic susceptibility testing was carried out by disc diffusion method. Results: A total of 1086 specimens were obtained and 58 samples suspicious of Shigella were specifically evaluated. The most prevalent isolated pathogen was Shigella sonnei (26/58) followed by E. coli (25/58) and Shigella flexneri (3/58). A large number of isolated bacteria were resistant to co-trimoxazole (Shigella spp: 100%, E. coli: 80%), azithromycin (Shigella spp: 70.4%, E. coli: 44.0%), ceftriaxone (Shigella spp: 88.9%, E. coli: 56.0%) and cefixime (Shigella spp: 85.2%, E. coli: 68.0%). About88.3% of S. sonnei isolates, one S. flexneri isolate, and 56% of E. coli strains were resistant to at least three antibiotic classes (multidrug resistant). Conclusion: Due to high levels of resistance to recommended and commonly used antibiotics for diarrhea, continuous monitoring of antibiotic resistance seems essential for determining best options of empirical therapy. PMID:25002896

Sadeghabadi, Azam Fatahi; Ajami, Ali; Fadaei, Reza; Zandieh, Masoud; Heidari, Elham; Sadeghi, Mahmoud; Ataei, Behrooz; Hoseini, Shervin Ghaffari

2014-01-01

322

Effect of bile on growth, peritoneal absorption, and blood clearance of Escherichia coli in E coli peritonitis  

SciTech Connect

The effect of intraperitoneal bile on growth, peritoneal absorption, and clearance of Escherichia coli was determined in E coli peritonitis in the rat. In E coli peritonitis, intraperitoneal bacterial counts gradually decreased, whereas they increased (after 2 hours) with subsequent development of bacteremia in E coli plus bile peritonitis. After an intraperitoneal injection of labeled bacteria, blood radioactivity was only initially lower in E coli plus bile peritonitis compared with E coli peritonitis. Clearance from blood was lower in E coli plus bile peritonitis than in E coli peritonitis. Organ localization was similar in E coli peritonitis and E coli plus bile peritonitis with decreased splenic, increased pulmonary, and unchanged hepatic uptakes compared with controls. Impaired peritoneal absorption of bacteria, together with impaired local host defense, is likely to enhance the noxious effect of bile in E coli peritonitis.

Andersson, R.; Schalen, C.; Tranberg, K.G. (Department of Surgery, Lund University, Lund (Sweden))

1991-06-01

323

Monitoring and classification of PAH toxicity using an immobilized bioluminescent bacteria.  

PubMed

An immobilized recombinant bioluminescent Escherichia coli strain, harboring a lac::luxCDABE fused plasmid, which shows lower bioluminescence levels when cellular metabolism is inhibited, was used to monitor the cellular toxicity of polycyclic aromatic hydrocarbons (PAHs). PAHs, classified as pericondensed (PCPAHs) or catacondensed (CCPAHs) according to their molecular structures, were differentiable according to the response of this biosensor. Only CCPAHs were found to cause cellular toxicity, resulting in a dose-dependent decrease in the bioluminescent output. The induction of cellular toxicity by CCPAHs and PCPAHs was compared with acute toxicity predictions obtained using the quantitative structure-activity relationship (QSAR) model. A good relationship was obtained between the toxicities determined with the bioluminescent response of the immobilized bacterium GC2 and the QSAR model. It was also found that the present study offers a new method of predicting the cellular toxicities of CCPAHs or PCPAHs using this biosensor. PMID:12706564

Lee, Hyun Joo; Villaume, Julien; Cullen, David C; Kim, Byoung Chan; Gu, Man Bock

2003-05-01

324

SbcCD Regulation and Localization in Escherichia coli?  

PubMed Central

The SbcCD complex and its homologues play important roles in DNA repair and in the maintenance of genome stability. In Escherichia coli, the in vitro functions of SbcCD have been well characterized, but its exact cellular role remains elusive. This work investigates the regulation of the sbcDC operon and the cellular localization of the SbcC and SbcD proteins. Transcription of the sbcDC operon is shown to be dependent on starvation and RpoS protein. Overexpressed SbcC protein forms foci that colocalize with the replication factory, while overexpressed SbcD protein is distributed through the cytoplasm. PMID:17644583

Darmon, Elise; Lopez-Vernaza, Manuel A.; Helness, Anne C.; Borking, Amanda; Wilson, Emily; Thacker, Zubin; Wardrope, Laura; Leach, David R. F.

2007-01-01

325

Cell growth and length distribution in Escherichia coli.  

PubMed Central

The length growth rate of an exponentially growing population of Escherichia coli B/r was calculated from the population length and birth length distributions. Cell elongation took place at a constant rate that doubled at a certain length. This change in rate was responsible for a sudden drop in the frequency of classes of cells longer than that length. Asymmetry in cell partition was able to generate cells both shorter and longer than the expected twofold range, but did not greatly modify the length distribution in between. Images PMID:348686

Cullum, J; Vicente, M

1978-01-01

326

Transcription factor distribution in Escherichia coli: studies with FNR protein  

PubMed Central

Using chromatin immunoprecipitation (ChIP) and high-density microarrays, we have measured the distribution of the global transcription regulator protein, FNR, across the entire Escherichia coli chromosome in exponentially growing cells. Sixty-three binding targets, each located at the 5? end of a gene, were identified. Some targets are adjacent to poorly transcribed genes where FNR has little impact on transcription. In stationary phase, the distribution of FNR was largely unchanged. Control experiments showed that, like FNR, the distribution of the nucleoid-associated protein, IHF, is little altered when cells enter stationary phase, whilst RNA polymerase undergoes a complete redistribution. PMID:17164287

Grainger, David C.; Aiba, Hirofumi; Hurd, Douglas; Browning, Douglas F.; Busby, Stephen J. W.

2007-01-01

327

Protein aggregation in Escherichia coli: role of proteases.  

PubMed

Protein aggregation is involved in several human diseases, and presumed to be an important process in protein quality control. In bacteria, aggregation of proteins occurs during stress conditions, such as heat shock. We studied the protein aggregates of Escherichia coli during heat shock. Our results demonstrate that the concentration and diversity of proteins in the aggregates depend on the availability of proteases. Aggregates obtained from mutants in the Lon (La) protease contain three times more protein than wild-type aggregates and show the broadest protein diversity. The results support the assumption that protein aggregates are formed from partially unfolded proteins that were not refolded by chaperones or degraded by proteases. PMID:11886743

Rosen, Ran; Biran, Dvora; Gur, Eyal; Becher, Dörte; Hecker, Michael; Ron, Eliora Z

2002-01-22

328

Molecular Evolution of the Escherichia Coli Chromosome. III. Clonal Frames  

PubMed Central

PCR fragments, 1500-bp, from 15 previously sequenced regions in the Escherichia coli chromosome have been compared by restriction analysis in a large set of wild (ECOR) strains. Prior published observations of segmental clonality are confirmed: each of several sequence types is shared by a number of strains. The rate of recombinational replacement and the average size of the replacements are estimated in a set of closely related strains in which a clonal frame is dotted with occasional stretches of DNA belonging to other clones. A clonal hierarchy is described. Some new comparative sequencing data are presented. PMID:1979037

Milkman, R.; Bridges, M. M.

1990-01-01

329

Molecular serogrouping of porcine enterotoxigenic Escherichia coli from Australia.  

PubMed

Enterotoxigenic Escherichia coli (ETEC) is a common etiological agent of neonatal, pre and post weaning diarrhoea in piglets. One of the most important steps in the diagnosis and epidemiological understanding of this organism is accurate serogrouping. In many instances, however, conventional serogrouping fails to produce accurate identification of serogroups. In this communication we report a modified and simplified molecular serogrouping method (rfb-RFLP) for the accurate identification of the most common porcine ETEC strains that cause neonatal, pre and post weaning diarrhoea in Australia. PMID:22093999

Abraham, Sam; Chin, James; Brouwers, Huub J M; Zhang, Ren; Chapman, Toni A

2012-01-01

330

Escherichia coli JA221 can suppress the UAG stop signal.  

PubMed

The Escherichia coli strain JA221 can suppress the UAG stop codon, although the existence of an amber suppressor tRNA has not previously been described for this strain. When using a plasmid to express alpha-sarcin, which has TAG as its stop signal, two proteins were obtained: a smaller protein corresponding in size to that of the expected protein, and a larger protein, which could be accounted for by the presence of a second stop codon (TGA) 18 base pairs downstream of the original. This feature of strain JA221 must therefore be considered when using this strain as a host for the production of recombinant proteins. PMID:7639999

Lacadena, J; Martínez del Pozo, A; Mancheño, J M; Gasset, M; Oñaderra, M; Gavilanes, J G

1995-08-01

331

Nucleotide sequence of the Escherichia coli entE gene.  

PubMed

The Escherichia coli entE gene encodes a polypeptide necessary in the latter stages of biosynthesis of the siderophore enterobactin. The entE gene and adjacent DNA were sequenced. The predicted EntE polypeptide consists of 536 amino acids and has a Mr of 58,299 and a net charge of -7.33. Genetic evidence combined with this and previous sequencing data indicate that the genes entCEB(G)A are transcribed as unit from a promoter upstream of entC. PMID:2525505

Staab, J F; Elkins, M F; Earhart, C F

1989-05-01

332

Microcin 25, a novel antimicrobial peptide produced by Escherichia coli.  

PubMed Central

Microcin 25, a peptide antibiotic excreted by an Escherichia coli strain isolated from human feces, was purified to homogeneity and characterized. Composition analysis and data from gel filtration indicated that microcin 25 may contain 20 amino acid residues. It has a blocked amino-terminal end. Microcin synthesis and immunity are plasmid determined, and the antibiotic was produced in minimal medium when the cultures entered the stationary phase of growth. The peptide appears to interfere with cell division, since susceptible cells filamented when exposed to it. This response does not seem to be mediated by the SOS system. Images PMID:1429464

Salomón, R A; Farías, R N

1992-01-01

333

Escherichia coli response to exogenous pyrophosphate and analogs.  

PubMed

The addition of exogenous pyrophosphate increases the growth yield and cAMP synthesis in stationary phase when Escherichia coli is grown in minimal medium. Pyrophosphate increases the yield by altering the enterobactin uptake system. We studied the physiological effects and examined how the E. coli transcriptome was modified when two structural analogs of pyrophosphate were added to the growth medium. Methylenediphosphonic acid or a high concentration of iron had the same positive effects as pyrophosphate on growth yield, cAMP synthesis and the repression of Fur-regulated genes. In contrast, imidodiphosphate did not affect these cellular processes significantly. The transcriptome modifications generated by pyrophosphate or methylenediphosphonic acid were more similar than those generated by imidodiphosphate or excess iron. The transcriptome data also indicated that processes other than iron uptake might be involved in the cellular response to exogenous pyrophosphate or methylenediphosphonic acid. PMID:12673060

Biville, Francis; Oshima, Taku; Mori, Hirotada; Kawagoe, Yuya; Bouvet, Odile; Rager, Marie-Noëlle; Perrotte-Piquemal, Marina; Danchin, Antoine

2003-01-01

334

Mounting of Escherichia coli spheroplasts for AFM imaging.  

SciTech Connect

The cytoplasmic membrane of Escherichia coli (E. coli) is the location of numerous, chemically specific transporters and recognition elements. Investigation of this membrane in vivo by atomic force microscopy (AFM) requires removal of the cell wall and stable immobilization of the spheroplast. AFM images demonstrate that spheroplasts can be secured with warm gelatin applied to the mica substrate just before the addition of a spheroplast suspension. The resulting preparation can be repeatedly imaged by AFM over the course of several hours. Confocal fluorescence imaging confirms the association of the spheroplasts with the gelatin layer. Gelatin molecules are known to reorder into a network after heating. Entrapment within this gelatin network is believed to be responsible for the immobilization of spheroplasts on mica.

Sullivan, Claretta J [ORNL; Morrell-Falvey, Jennifer L [ORNL; Allison, David P [ORNL; Doktycz, Mitchel John [ORNL

2005-11-01

335

Isolation and characterization of isoprene mutants of Escherichia coli.  

PubMed Central

Isoprenoid compounds are found in all organisms. In Escherichia coli the isoprene pathway has three distinct branches: the modification of tRNA; the respiratory quinones ubiquinone and menaquinone; and the dolichols, which are long-chain alcohols involved in cell wall biosynthesis. Very little is known about procaryotic isoprene biosynthesis compared with what is known about eucaryote isoprene biosynthesis. This study approached some of the questions about isoprenoid biosynthesis and regulation in procaryotes by isolating and characterizing mutants in E. coli. Mutants were selected by determining their resistance to low levels of aminoglycoside antibiotics, which require an electron transport chain for uptake into bacterial cells. The mutants were characterized with regard to their phenotypes, map positions, enzymatic activities, and total ubiquinone content. In particular, the enzymes studied were isopentenyldiphosphate delta-isomerase (EC 5.3.3.2), farnesyldiphosphate synthetase (EC 2.5.1.1), and higher prenyl transferases. PMID:2661529

Sherman, M M; Petersen, L A; Poulter, C D

1989-01-01

336

Global Analysis of Extracytoplasmic Stress Signaling in Escherichia coli  

PubMed Central

The Bae, Cpx, Psp, Rcs, and ?E pathways constitute the Escherichia coli signaling systems that detect and respond to alterations of the bacterial envelope. Contributions of these systems to stress response have previously been examined individually; however, the possible interconnections between these pathways are unknown. Here we investigate the dynamics between the five stress response pathways by determining the specificities of each system with respect to signal-inducing conditions, and monitoring global transcriptional changes in response to transient overexpression of each of the effectors. Our studies show that different extracytoplasmic stress conditions elicit a combined response of these pathways. Involvement of the five pathways in the various tested stress conditions is explained by our unexpected finding that transcriptional responses induced by the individual systems show little overlap. The extracytoplasmic stress signaling pathways in E. coli thus regulate mainly complementary functions whose discrete contributions are integrated to mount the full adaptive response. PMID:19763168

Bury-Mone, Stephanie; Nomane, Yanoura; Reymond, Nancie; Barbet, Romain; Jacquet, Eric; Imbeaud, Sandrine; Jacq, Annick; Bouloc, Philippe

2009-01-01

337

Genetic characterization of moaB mutants of Escherichia coli.  

PubMed

The moaABCDE operon of Escherichia coli encodes enzymes essential for the biosynthesis of the molybdenum cofactor (Moco). However, the role of the moaB gene within this operon has remained enigmatic. Here, we have investigated the effect of moaB defects on two phenotypes diagnostic for Moco-deficiency: chlorate-resistance and sensitivity to the base analog 6-N-hydroxylaminopurine (HAP). We found that transposon insertions in moaB caused partial Moco-deficiency associated with chlorate-resistance, but not for HAP-sensitivity. On the other hand, in-frame deletions of moaB, or moaB overexpression, had no effect on either phenotype. Our combined data are consistent with the lack of any role for MoaB in Moco biosynthesis in E. coli. PMID:23680484

Kozmin, Stanislav G; Schaaper, Roel M

2013-09-01

338

Cellulosic hydrolysate toxicity and tolerance mechanisms in Escherichia coli  

PubMed Central

The sustainable production of biofuels will require the efficient utilization of lignocellulosic biomass. A key barrier involves the creation of growth-inhibitory compounds by chemical pretreatment steps, which ultimately reduce the efficiency of fermentative microbial biocatalysts. The primary toxins include organic acids, furan derivatives, and phenolic compounds. Weak acids enter the cell and dissociate, resulting in a drop in intracellular pH as well as various anion-specific effects on metabolism. Furan derivatives, dehydration products of hexose and pentose sugars, have been shown to hinder fermentative enzyme function. Phenolic compounds, formed from lignin, can disrupt membranes and are hypothesized to interfere with the function of intracellular hydrophobic targets. This review covers mechanisms of toxicity and tolerance for these compounds with a specific focus on the important industrial organism Escherichia coli. Recent efforts to engineer E. coli for improved tolerance to these toxins are also discussed. PMID:19832972

Mills, Tirzah Y; Sandoval, Nicholas R; Gill, Ryan T

2009-01-01

339

Atypical Enteropathogenic Escherichia coli Infection and Prolonged Diarrhea in Children  

PubMed Central

Some clinical isolates of enteropathogenic Escherichia coli (EPEC) lack bundle-forming pili and are termed atypical EPEC. The aim of this study was to determine if atypical EPEC are pathogens by comparing the clinical features of patients infected with atypical EPEC with those of children infected with other causative agents of diarrhea. Fecal samples obtained from children attending the Royal Children's Hospital in Melbourne for investigation of diarrhea were examined for adenovirus, rotavirus, Campylobacter spp., Salmonella spp., protozoa, and pathogenic E. coli. Clinical data were obtained by using a standardized pro forma and analyzed separately. Patients infected with atypical EPEC experienced mild, nondehydrating, and noninflammatory diarrhea that was not particularly associated with fever, vomiting, or abdominal pain. However, the duration of diarrhea in patients infected with atypical EPEC was significantly longer than that caused by the other species or where no pathogens were identified. Infection with atypical EPEC is associated with prolonged diarrhea. PMID:16704807

Nguyen, Rang N.; Taylor, Louise S.; Tauschek, Marija

2006-01-01

340

Purification and Characterization of Escherichia coli MreB Protein*  

PubMed Central

The actin homolog MreB is required in rod-shaped bacteria for maintenance of cell shape and is intimately connected to the holoenzyme that synthesizes the peptidoglycan layer. The protein has been reported variously to exist in helical loops under the cell surface, to rotate, and to move in patches in both directions around the cell surface. Studies of the Escherichia coli protein in vitro have been hampered by its tendency to aggregate. Here we report the purification and characterization of native E. coli MreB. The protein requires ATP hydrolysis for polymerization, forms bundles with a left-hand twist that can be as long as 4 ?m, forms sheets in the presence of calcium, and has a critical concentration for polymerization of 1.5 ?m. PMID:23235161

Nurse, Pearl; Marians, Kenneth J.

2013-01-01

341

Production of Disulfide-Bonded Proteins in Escherichia coli.  

PubMed

Production of recombinant proteins at high yields in Escherichia coli requires extensive optimization of expression conditions. Production is further complicated for proteins that require specific post-translational modifications for their eventual folding. One common and particularly important post-translational modification is oxidation of the correct pair of cysteines to form a disulfide bond. This unit describes methods to produce disulfide-bonded proteins in E. coli in either the naturally oxidizing periplasm or the cytoplasm of appropriately engineered cells. The focus is on variables key to improving the oxidative folding of disulfide-bonded proteins, with the aim of helping the researcher optimize expression conditions for a protein of interest. Curr. Protoc. Mol. Biol. 108:16.1B.1-16.1B.21. © 2014 by John Wiley & Sons, Inc. PMID:25271713

Ke, Na; Berkmen, Mehmet

2014-01-01

342

Nanomechanical motion of Escherichia coli adhered to a surface  

NASA Astrophysics Data System (ADS)

Nanomechanical motion of bacteria adhered to a chemically functionalized silicon surface is studied by means of a microcantilever. A non-specific binding agent is used to attach Escherichia coli (E. coli) to the surface of a silicon microcantilever. The microcantilever is kept in a liquid medium, and its nanomechanical fluctuations are monitored using an optical displacement transducer. The motion of the bacteria couples efficiently to the microcantilever well below its resonance frequency, causing a measurable increase in the microcantilever fluctuations. In the time domain, the fluctuations exhibit large-amplitude low-frequency oscillations. In corresponding frequency-domain measurements, it is observed that the mechanical energy is focused at low frequencies with a 1/f?-type power law. A basic physical model is used for explaining the observed spectral distribution of the mechanical energy. These results lay the groundwork for understanding the motion of microorganisms adhered to surfaces and for developing micromechanical sensors for bacteria.

Lissandrello, C.; Inci, F.; Francom, M.; Paul, M. R.; Demirci, U.; Ekinci, K. L.

2014-09-01

343

Allostery and cooperativity in Escherichia coli aspartate transcarbamoylase.  

PubMed

The allosteric enzyme aspartate transcarbamoylase (ATCase) from Escherichia coli has been the subject of investigations for approximately 50 years. This enzyme controls the rate of pyrimidine nucleotide biosynthesis by feedback inhibition, and helps to balance the pyrimidine and purine pools by competitive allosteric activation by ATP. The catalytic and regulatory components of the dodecameric enzyme can be separated and studied independently. Many of the properties of the enzyme follow the Monod, Wyman Changeux model of allosteric control thus E. coli ATCase has become the textbook example. This review will highlight kinetic, biophysical, and structural studies which have provided a molecular level understanding of how the allosteric nature of this enzyme regulates pyrimidine nucleotide biosynthesis. PMID:22198283

Kantrowitz, Evan R

2012-03-15

344

Allostery and cooperativity in Escherichia coli Aspartate Transcarbamoylase  

PubMed Central

The allosteric enzyme aspartate transcarbamoylase (ATCase) from Escherichia coli has been the subject of investigations for approximately 50 years. This enzyme controls the rate of pyrimidine nucleotide biosynthesis by feedback inhibition, and helps to balance the pyrimidine and purine pools by competitive allosteric activation by ATP. The catalytic and regulatory components of the dodecameric enzyme can be separated and studied independently. Many of the properties of the enzyme follow the Monod, Wyman Changeux model of allosteric control thus E. coli ATCase has become the textbook example. This review will highlight kinetic, biophysical, and structural studies which have provided a molecular level understanding of how the allosteric nature of this enzyme regulates pyrimidine nucleotide biosynthesis. PMID:22198283

Kantrowitz, Evan R.

2012-01-01

345

Engineering Escherichia coli for improved ethanol production from gluconate.  

PubMed

We report on engineering Escherichia coli to produce ethanol at high yield from gluconic acid (gluconate). Knocking out genes encoding for the competing pathways (l-lactate dehydrogenase and pyruvate formate lyase A) in E. coli KO11 eliminated lactate production, lowered the carbon flow toward acetate production, and improved the ethanol yield from 87.5% to 97.5% of the theoretical maximum, while the growth rate of the mutant strain was about 70% of the wild type. The corresponding genetic modifications led to a small improvement of ethanol yield from 101.5% to 106.0% on glucose. Deletion of the pyruvate dehydrogenase gene (pdh) alone improved the ethanol yield from 87.5% to 90.4% when gluconate was a substrate. The growth rate of the mutant strain was identical to that of the wild type. The corresponding genetic modification led to no improvements on ethanol yield on glucose. PMID:23942377

Hildebrand, Amanda; Schlacta, Theresa; Warmack, Rebeccah; Kasuga, Takao; Fan, Zhiliang

2013-10-10

346

Pathogenic Escherichia coli in rural household container waters.  

PubMed

Plastic containers in the range of 5-20 L are widely used - especially in rural African settings - to collect, transport and store water for domestic use, including drinking, bathing and hygiene. The pathogen content of the waters in these containers has not been adequately characterized as yet. This paper presents the primary findings of a synoptic survey of drinking water quality samples from these containers and involved collection of bacterial indicator and pathogenicity gene data. In total, 571 samples of a variety of waters were taken in rural communities in South Africa and the Escherichia coli numbers measured. Of the E. coli positive samples, 46% (n = 148) were screened for the presence of E. coli pathogen gene markers. Though synoptic, the survey provided many insights into the issues that drove the study. Container use markedly degraded water quality as judged by indicator counts, even where improved water supply services were in place. Household container use also appeared to promote regrowth or contamination of containers with pathogenic E. coli strains. Polymerase chain reaction (PCR) analysis also showed that the diversity of potential pathogenic E. coli carrying virulence genes was great. All seven genes screened for (Ial, Stx1, Stx2, EaeA, Eagg, ST, LT) were found in the waters, alone or as mixtures (number of different combinations = 31) including those characteristic of the more dangerous invasive and haemorrhagic E. coli strains. Given the central role of containers in the management of water supply to rural communities, it is clear the microbiology of these waters requires much further characterization. PMID:23508146

Jagals, P; Barnard, T G; Mokoena, M M; Ashbolt, N; Roser, D J

2013-01-01

347

Production of a bacteriolysin by a hemolytic Escherichia coli strain.  

PubMed Central

Nonhemolytic Escherichia coli were outnumbered by hemolytic E. coli within 24 h after being inoculated in a mixed culture at an initial ratio of 200 nonhemolytic to 1 hemolytic organism. The hemolytic strain was found to produce a cell-free, filterable substance which causes lysis of nonhemolytic E. coli B when grown in liquid cultures but not when grown on agar plates. The bacteriolysin is inactivated by boiling, by freezing and thawing, and by incubation with trypsin. The inability to inhibit growth on an agar plate, dependence on cell concentration for its effect, lysis of the sensitive cells, and appearance of phage particles in the cell lysates suggest that this substance is not like colicins or microcins previously described. After lysis of E. coli B, bacteriophage particles were visible in transmission electron micrographs of material pelleted by ultracentrifugation. However, no bacteriophage were observed in pellets from the bacteriolysin-containing supernatants before lysis of E. coli B. Failure to find bacteriophage in these preparations, and the fact that some bacteriolysin activity remains in the supernatant solution after centrifugation at 150,000 X g for 6.5 h, indicate that the bacteriolysin is not itself a bacteriophage. Exposure of E. coli B to UV light and mitomycin C did not induce production of a temperate phage. The properties of this system, in which a cell-free substance produced by one strain of bacteria causes lysis of another strain, appear to differ from those of the various types of bacteriocins and bacteriophages described to date. Images PMID:6350182

Jorgensen, S E; Mussen, H K; Mulcahy, P F; Wu, G K

1983-01-01

348

Production of a bacteriolysin by a hemolytic Escherichia coli strain.  

PubMed

Nonhemolytic Escherichia coli were outnumbered by hemolytic E. coli within 24 h after being inoculated in a mixed culture at an initial ratio of 200 nonhemolytic to 1 hemolytic organism. The hemolytic strain was found to produce a cell-free, filterable substance which causes lysis of nonhemolytic E. coli B when grown in liquid cultures but not when grown on agar plates. The bacteriolysin is inactivated by boiling, by freezing and thawing, and by incubation with trypsin. The inability to inhibit growth on an agar plate, dependence on cell concentration for its effect, lysis of the sensitive cells, and appearance of phage particles in the cell lysates suggest that this substance is not like colicins or microcins previously described. After lysis of E. coli B, bacteriophage particles were visible in transmission electron micrographs of material pelleted by ultracentrifugation. However, no bacteriophage were observed in pellets from the bacteriolysin-containing supernatants before lysis of E. coli B. Failure to find bacteriophage in these preparations, and the fact that some bacteriolysin activity remains in the supernatant solution after centrifugation at 150,000 X g for 6.5 h, indicate that the bacteriolysin is not itself a bacteriophage. Exposure of E. coli B to UV light and mitomycin C did not induce production of a temperate phage. The properties of this system, in which a cell-free substance produced by one strain of bacteria causes lysis of another strain, appear to differ from those of the various types of bacteriocins and bacteriophages described to date. PMID:6350182

Jorgensen, S E; Mussen, H K; Mulcahy, P F; Wu, G K

1983-09-01

349

Enteroaggregative Escherichia coli associated with a foodborne outbreak of gastroenteritis.  

PubMed

This study investigated two foodborne outbreaks of gastroenteritis that occurred 10 days apart among individuals who had meals at the restaurant of a farm holiday resort. Mild gastrointestinal symptoms were reported and none of the patients needed hospitalization. Mean incubation times were 45 and 33 h, and the overall attack rates were 43.5 and 58.3%, respectively. Stool sample examination was negative for common enteric pathogens in both outbreaks. Specimens from 13 people involved in the second outbreak and 3 restaurant staff were examined for diarrhoeagenic Escherichia coli. An enteroaggregative E. coli (EAEC) strain of serotype O92:H33 was isolated from six participants and one member of staff. In particular, the EAEC strain was isolated from five of the six cases of diarrhoea examined. The strain showed an aggregative pattern of adherence to HEp-2 cells, did not produce a biofilm and possessed the virulence-related genes aat, aggR, aap and set1A, but not the astA gene. A retrospective cohort study indicated a pecorino cheese made with unpasteurized sheep milk as the possible source (P<0.001). Samples of the cheese had E. coli counts higher than 10(6) c.f.u. g(-1), but the outbreak EAEC strain was not isolated. This report confirms that EAEC infections are probably underdiagnosed because of the limited availability of laboratories capable of identifying this group of pathogenic E. coli. PMID:18719185

Scavia, Gaia; Staffolani, Monica; Fisichella, Stefano; Striano, Gianluca; Colletta, Stefano; Ferri, Giovanni; Escher, Martina; Minelli, Fabio; Caprioli, Alfredo

2008-09-01

350

Recovery of chlorine-exposed Escherichia coli in estuarine microcosms.  

PubMed

Laboratory microcosm experiments were performed to determine whether chlorine-exposed Escherichia coli are capable of recovery (i.e., increase in numbers of culturable cells) in estuarine waters and if so what water-quality parameters are responsible for this recovery. Suspensions of E. coli were exposed to 0.5 mg L(-1) of chlorine for 5 min followed by dechlorination with sodium thiosulfate. The chlorine-exposed bacteria were introduced into 2-L microcosms containing estuarine water collected from the Seacoast region of New Hampshire. Culturable cells in the microcosms were enumerated at 0, 10, 24, 48, and 74 h. In all estuarine microcosms the number of culturable cells increased by factors ranging from 2.8 to 50 over the 74-h incubation period. Multiple linear regression analyses indicated that ammonium and salinity were most significantly correlated with the recovery of E. coli over the 74-h incubation period; however, ammonium concentrations were strongly correlated with dissolved organic carbon and total dissolved nitrogen, making it impossible to determine with any degree of certainty the unique effect nitrogen or carbon had on recovery. The extensive recovery observed in our study indicates that following exposure to concentrations of chlorine that cause cell injury rather than death, numbers of culturable E. coli may increase significantly when discharged into estuarine waters. Thus, depending on the effectiveness of the chlorination process, the regular monitoring of chlorinated wastewater treatment effluent may underestimate the true impact on water-quality and public health risks. PMID:15926556

Bolster, Carl H; Bromley, Jonathan M; Jones, Stephen H

2005-05-01

351

Isoaspartate in Ribosomal Protein S11 of Escherichia coli  

PubMed Central

Isoaspartyl sites, in which an aspartic acid residue is linked to its C-flanking neighbor via its ?-carboxyl side chain, are generally assumed to be an abnormal modification arising as proteins age. The enzyme protein l-isoaspartate methyltransferase (PIMT), present in many bacteria, plants, and animals, catalyzes the conversion of isoaspartate to normal ?-linked aspartyl bonds and is thought to serve an important repair function in cells. Having introduced a plasmid into Escherichia coli that allows high-level expression of rat PIMT, we explored the possibility that the rat enzyme reduces isoaspartate levels in E. coli proteins, a result predicted by the repair hypothesis. The present study demonstrates that this is indeed the case; E. coli cells expressing rat PIMT had significantly lower isoaspartate levels than control cells, especially in stationary phase. Moreover, the distribution of isoaspartate-containing proteins in E. coli differed dramatically between logarithmic- and stationary-phase cultures. In stationary-phase cells, a number of proteins in the molecular mass range of 66 to 14 kDa contained isoaspartate, whereas in logarithmic-phase cells, nearly all of the detectable isoaspartate resided in a single 14-kDa protein which we identified as ribosomal protein S11. The near stoichiometric levels of isoaspartate in S11, estimated at 0.5 mol of isoaspartate per mol of S11, suggests that this unusual modification may be important for S11 function. PMID:10217780

David, Cynthia L.; Keener, John; Aswad, Dana W.

1999-01-01

352

Modeling Escherichia coli removal in constructed wetlands under pulse loading.  

PubMed

Manure-borne pathogens are a threat to water quality and have resulted in disease outbreaks globally. Land application of livestock manure to croplands may result in pathogen transport through surface runoff and tile drains, eventually entering water bodies such as rivers and wetlands. The goal of this study was to develop a robust model for estimating the pathogen removal in surface flow wetlands under pulse loading conditions. A new modeling approach was used to describe Escherichia coli removal in pulse-loaded constructed wetlands using adaptive neuro-fuzzy inference systems (ANFIS). Several ANFIS models were developed and validated using experimental data under pulse loading over two seasons (winter and summer). In addition to ANFIS, a mechanistic fecal coliform removal model was validated using the same sets of experimental data. The results showed that the ANFIS model significantly improved the ability to describe the dynamics of E. coli removal under pulse loading. The mechanistic model performed poorly as demonstrated by lower coefficient of determination and higher root mean squared error compared to the ANFIS models. The E. coli concentrations corresponding to the inflection points on the tracer study were keys to improving the predictability of the E. coli removal model. PMID:24231031

Hamaamin, Yaseen A; Adhikari, Umesh; Nejadhashemi, A Pouyan; Harrigan, Timothy; Reinhold, Dawn M

2014-03-01

353

Direct cadaverine production from cellobiose using ?-glucosidase displaying Escherichia coli  

PubMed Central

In this study, we demonstrate the one-step production of cadaverine (1,5-diaminopentane) from cellobiose using an Escherichia coli strain displaying ?-glucosidase (BGL) on its cell surface. L-lysine decarboxylase (CadA) derived from E. coli and BGL from Thermobifida fusca YX (Tfu0937) fused to the anchor protein Blc from E. coli were co-expressed using E. coli as a host. The expression of CadA was confirmed by Western blotting and BGL activity on the cell surface was evaluated using pNPG as a substrate. Growth on cellobiose as the sole carbon source was also achieved. The OD600 value of the BGL and CadA co-expressing strain was 8.0 after 48 h cultivation, which is higher than that obtained by growth on glucose (5.4 after 48 h cultivation). The engineered strain produced cadaverine from cellobiose more effectively than from glucose: 6.1 mM after 48 h from 28 g/L of consumed cellobiose, vs. 3.3 mM from 20 g/L of consumed glucose. PMID:24206923

2013-01-01

354

Sources of variation of Escherichia coli concentrations in bivalve molluscs.  

PubMed

Bivalve molluscs can concentrate contaminants, including pathogenic microorganisms, from the water column during their normal filter-feeding activity. In the European Union, the risk of human and animal faecal contamination in bivalves is estimated by determining the concentration of Escherichia coli in time-series samples from production areas. A structured field study was undertaken to determine the extent to which such concentrations varied between sites, sampling occasions and shellfish species and to determine the residual variability of the method. E. coli was enumerated in three species of bivalve mollusc (Crassostrea gigas, Mytilus spp. and Pecten maximus) co-located in each of three geographically separate commercial shellfisheries. The data were subjected to analysis of variance (ANOVA). This showed that the effects of site, sampling occasion, species and site/sampling occasion interaction were all significant. The proportion of variation due to site was markedly greater than that due to other factors. Post-ANOVA analysis showed that the concentration of E. coli in P. maximus was significantly higher than in the other two species. Mytilus spp. and C. gigas exhibited comparable levels of E. coli. The observed standard deviation of the most probable number method in the study was 0.33 log(10). PMID:23428551

Lee, R J; Silk, R

2013-03-01

355

A monkey model for enterohemorrhagic Escherichia coli infection.  

PubMed

Adult Macaca radiata (n=22) were infected intragastrically with 10(12) Escherichia coli O157:H7 strain 84-01, which produces Shiga toxins 1 and 2. Clinical symptoms and bacterial excretion were documented in each monkey for a specified time period before they were killed. At necropsy, samples were obtained for culture and histologic and ultrastructural examination. Seventeen monkeys had diarrhea: E. coli O157 was isolated from postinfection stool samples from all monkeys and from autopsy cultures for 14 of 22 monkeys. Histologic examination showed attaching-effacing lesions, which appeared at 12 h and persisted for 7 days, in 12 monkeys. Widening of the intercellular spaces, degeneration and vacuolization of the epithelial cells, epithelial tufting, extrusion of epithelial cells, and neutrophilic infiltration were characteristic features seen in 20 of the 22 infected monkeys but not in 4 control monkeys. This monkey model closely parallels the early stages of the disease produced by E. coli O157:H7 and would be useful in the further study of pathogenic mechanisms and prevention methods in enterohemorrhagic E. coli infections. PMID:11424020

Kang, G; Pulimood, A B; Koshi, R; Hull, A; Acheson, D; Rajan, P; Keusch, G T; Mathan, V I; Mathan, M M

2001-07-15

356

MinD and MinE Interact with Anionic Phospholipids and Regulate Division Plane Formation in Escherichia coli*S  

E-print Network

in Escherichia coli*S Received for publication,August 3, 2012, and in revised form, September 22, 2012 Published machinery in Escherichia coli cells. Previous studies identified that interactions of Min, kinetics, and ATPase activity of E. coli MinD, MinE, and MinDE binding to supported lipid bilayers

Weibel, Douglas B.

357

SHORT REPORT Open Access Escherichia coli BdcA controls biofilm dispersal in  

E-print Network

SHORT REPORT Open Access Escherichia coli BdcA controls biofilm dispersal in Pseudomonas aeruginosa that BdcA controls Escherichia coli biofilm dispersal by binding the ubiquitous bacterial signal cyclic by increasing motility, decreasing aggregation, and decreasing production of biofilm adhesins. Findings: Here we

Wood, Thomas K.

358

Why Are Translationally Sub-Optimal Synonymous Codons Used in Escherichia coli?  

E-print Network

Why Are Translationally Sub-Optimal Synonymous Codons Used in Escherichia coli? Nick G.C. Smith selection favors certain synony- mous codons which aid translation in Escherichia coli, yet codons not favored by translational selection persist. We use the frequency distributions of synonymous poly

Eyre-Walker, Adam

359

Specificity of a Monoclonal Antibody for Alkaline Phosphatase in Escherichia coli and Shigella Species  

Microsoft Academic Search

The specificity of monoclonal antibody 2E5 for the alkaline phosphatase of Escherichia coli was studied against the alkaline phosphatases of 251 other bacterial strains. The organisms used included members of the six species of the genus Escherichia (E. coli, E. fergusonii, E. hermannii, E. blattae, E. vulneris, E. adecarboxylata), 41 species representing the family Enterobacteriaceae, and, in addition, Pseudomonas aeruginosa,

P. A. TRINELY; C. MIELCAREK; F. GAVINI; C. CARON; D. IZARD

360

2002 Blackwell Science Ltd Gene expression profiling of Escherichia coli growth  

E-print Network

© 2002 Blackwell Science Ltd Gene expression profiling of Escherichia coli growth transitions to determine the system response in Escherichia coli cells experiencing transient growth arrest caused: an expanded stringent response model phate (ppGpp), which provides for the cell's rapid response to growth

Conway, Tyrrell

361

Toxicity of density separation media to Escherichia coli and Mycobacterium strain PC01  

E-print Network

Toxicity of density separation media to Escherichia coli and Mycobacterium strain PC01 studied how various density separation media affected the viability of Escherichia coli to quantify abundant surface area for attached bacterial growth and metabolism of or- ganic matter. Depending

Rockne, Karl J.

362

Minimal Reaction Sets for Escherichia coli Metabolism under Different Growth Requirements and Uptake Environments  

E-print Network

ARTICLES Minimal Reaction Sets for Escherichia coli Metabolism under Different Growth Requirements growth rates on different substrates is introduced and applied to a flux balance model of the Escherichia and the growth requirements imposed on the network. Specifically, we predict that the E. coli network

Maranas, Costas

363

Quantum-like model of glucose effect on Escherichia coli growth  

NASA Astrophysics Data System (ADS)

Recently, we proposed a new method to compute probabilities which do not satisfy basic law in classical probability theory. In this note, we analyze glucose effect in Escherichia coli's growth with the method, and we show an invariant quantity which Escherichia coli has.

Asano, Masanari; Basieva, Irina; Khrennikov, Andrei; Ohya, Masanori; Tanaka, Yoshiharu; Yamato, Ichiro

2012-03-01

364

Defective Dissociation of a "Slow" RecA Mutant Protein Imparts an Escherichia coli Growth Defect*  

E-print Network

Defective Dissociation of a "Slow" RecA Mutant Protein Imparts an Escherichia coli Growth Defect recom- binase in Escherichia coli. RecA homologues are present in nearly every organism, and closely lacking RecA protein, the growth of the cells is severely curtailed. The slow growth defect is alleviated

Cox, Michael M.

365

In situ bioprocess monitoring of Escherichia coli bioreactions using Raman spectroscopy  

E-print Network

In situ bioprocess monitoring of Escherichia coli bioreactions using Raman spectroscopy Harry L from in situ measured Raman spectra in Escherichia coli bioreactions. Attenuation due to light for early identification of poor growth conditions, increasing overall experimental throughput. In all cases

Sinskey, Anthony J.

366

The Green Alga, Cladophora, Promotes Escherichia coli Growth and Contamination of Recreational Waters in Lake Michigan  

Microsoft Academic Search

A linkage between Cladophora mats and exceedances of recreational water quality criteria has been suggested, but not directly studied. Th is study investigates the spatial and temporal association between Escherichia coli concentrations within and near Cladophora mats at two northwestern Lake Michigan beaches in Door County, Wisconsin. Escherichia coli concentrations in water underlying mats were signifi cantly greater than surrounding

Muruleedhara Byappanahalli; Richard Whitman USGS

367

Escherichia coli offers a means for the rapid and economical production of recombinant proteins. These advantages,  

E-print Network

195 Escherichia coli offers a means for the rapid and economical production of recombinant proteins phosphotransferase system t-PA tissue plasminogen activator Introduction Escherichia coli was the first host used of such economically sensitive products as insulin and bovine growth hormone. Although significant progress has been

Lebendiker, Mario

368

Enhanced Hydrogen Production in Escherichia coli Through Chemical Mutagenesis, Gene Deletion, and Transposon Mutagenesis  

E-print Network

ENHANCED HYDROGEN PRODUCTION IN ESCHERICHIA COLI THROUGH CHEMICAL MUTAGENESIS, GENE DELETION, AND TRANSPOSON MUTAGENESIS A Thesis by ANDREA JULIANA GARZON SANABRIA Submitted to the Office of Graduate Studies of Texas A...&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE May 2010 Major Subject: Chemical Engineering ENHANCED HYDROGEN PRODUCTION IN ESCHERICHIA COLI THROUGH CHEMICAL MUTAGENESIS, GENE DELETION...

Garzon Sanabria, Andrea Juliana

2011-08-08

369

Structural and Biochemical Characterization of a Quinol Binding Site of Escherichia coli Nitrate Reductase A*  

E-print Network

Structural and Biochemical Characterization of a Quinol Binding Site of Escherichia coli Nitrate of Escherichia coli nitrate re- ductase A (NarGHI) in complex with pentachlorophenol has been determined to 2.0 Ã? of resolution. We have shown that pentachlorophenol is a potent inhibitor of quinol:nitrate oxidoreductase

Strynadka, Natalie

370

Structure of the Heme d of Penicillium vitale and Escherichia coli Catalases*  

E-print Network

Structure of the Heme d of Penicillium vitale and Escherichia coli Catalases* (Received-hydroxychlorin -spirolactone has been found in the crystal structures of Penicillium vitale catalase and Escherichia coli catalase hydroperoxidase II (HPII). The absolute stereochemistry of the two heme d chiral car- bon atoms

371

Antibiotics Susceptibility Pattern of Escherichia coli Strains Isolated from Chickens with Colisepticemia in Tabriz Province, Iran  

Microsoft Academic Search

Antimicrobial agents are used extremely in order to reducing the enormous losses caused by Escherichia coli infections (colibacillosis) in Iran poultry industry. In this investigation fifty avian pathogenic Escherichia coli (APEC) strains isolated from broiler chickens with colisepticemia and examined for susceptibility to antimicrobials of veterinary and human significance. In vitro antibiotic activities of 3 2 antibiotic substances against the

2006-01-01

372

Chemotaxis of Escherichia coli to Pyrimidines: a New Role for the Signal Transducer Tap  

Microsoft Academic Search

Escherichia coli exhibits chemotactic responses to sugars, amino acids, and dipeptides, and the responses are mediated by methyl-accepting chemotaxis proteins (MCPs). Using capillary assays, we demonstrated that Escherichia coli RP437 is attracted to the pyrimidines thymine and uracil and the response was constitutively expressed under all tested growth conditions. All MCP mutants lacking the MCP Tap protein showed no response

Xianxian Liu; Rebecca E. Parales

2008-01-01

373

Inhibition of the ATPase activity of Escherichia coli ATP synthase by magnesium fluoride  

E-print Network

Inhibition of the ATPase activity of Escherichia coli ATP synthase by magnesium fluoride Zulfiqar activity of Escherichia coli ATP synthase by magnesium fluoride (MgFx) was studied. Wild-type F1-ATPase synthesis mechanism; Magnesium fluoride; ATPase inhibition; Transition state analog 1. Introduction ATP

Zulfiqar Ahmad

374

Escherichia coli maltose-binding protein is uncommonly effective at promoting the solubility  

E-print Network

Escherichia coli maltose-binding protein is uncommonly effective at promoting the solubility of a recombinant protein in Escherichia coli, obtaining the protein in a soluble, biologically active form-prone polypeptide to a highly soluble partner. To study this phenomenon in greater detail, we compared the ability

375

DNA-damaging activity of patulin in Escherichia coli.  

PubMed Central

At a concentration of 10 micrograms/ml, patulin caused single-strand DNA breaks in living cells of Escherichia coli. At 50 micrograms/ml, double-strand breaks were observed also. Single-strand breaks were repaired in the presence of 10 micrograms of patulin per ml within 90 min when the cells were incubated at 37 degrees C in M9-salts solution without a carbon source. The same concentration also induced temperature-sensitive lambda prophage and a prophage of Bacillus megaterium. When an in vitro system with permeabilized Escherichia coli cells was used, patulin at 10 micrograms/ml induced DNA repair synthesis and inhibited DNA replication. The in vivo occurrence of DNA strand breaks and DNA repair correlated with the in vitro induction of repair synthesis. In vitro the RNA synthesis was less affected, and overall protein synthesis was not inhibited at 10 micrograms/ml. Only at higher concentrations (250 to 500 micrograms/ml) was inhibition of in vitro protein synthesis observed. Thus, patulin must be regarded as a mycotoxin with selective DNA-damaging activity. PMID:2431653

Lee, K S; Roschenthaler, R J

1986-01-01

376

Cleaving yeast and Escherichia coli genomes at a single site  

SciTech Connect

The 15-megabase pair Saccharomyces cerevisiae and the 4.7-megabase pair Escherichia coli genomes were completely cleaved at a single predetermined site by means of the Achilles' heel cleavage (AC) procedure. The symmetric lac operator (lacO{sub s}) was introduced into the circular Escherichia coli genome and into one of the 16 yeast chromosomes. Intact chromosomes from the resulting strains were prepared in agarose microbeads and methylated with Hha I (5{prime}-GCGC) methyltransferase (M{center dot}Hha I) in the presence of lac repressor (LacI). All Hae II sites ({prime}-{sub G}{sup A}GCGC{sub C}{sup T}) with the exception of the one in lacO{sub s}, which was protected by LacI, were modified and thus no longer recognized by Hae II. After inactivation of M{center dot}Hha I and LacI, Hae II was used to completely cleave the chromosomes specifically at the inserted lacO{sub s}. These experiments demonstrate the feasibility of using the AC approach to efficiently extend the specificity of naturally occurring restriction enzymes and create new tools for the mapping and precise molecular dissection of multimegabase genomes.

Koob, M.; Szybalski, W. (Univ. of Wisconsin, Madison (USA))

1990-10-12

377

Involvement of Src tyrosine kinase in Escherichia coli invasion of human brain microvascular endothelial cells  

Microsoft Academic Search

Invasion of brain microvascular endothelial cells is a prerequisite for successful crossing of the blood–brain barrier by Escherichia coli (E. coli), but the underlying mechanism remains unclear. Here we showed activation of Src tyrosine kinase in E. coli K1 invasion of human brain microvascular endothelial cells (HBMEC). E. coli invasion of HBMEC and the E. coli-induced rearrangement of actin filaments

Wei Liu; Wei-Dong Zhao; Jin-Chun Yan; Zhi-Yuan Ren; Wen-Gang Fang; Li Zhu; De-Shu Shang; Yu-Hua Chen

2010-01-01

378

Escherichia coli bioreporters for the detection of 2,4-dinitrotoluene and 2,4,6-trinitrotoluene.  

PubMed

The primary explosive found in most land mines, 2,4,6-trinitrotoluene (2,4,6-TNT), is often accompanied by 2,4-dinitrotoluene (2,4-DNT) and 1,3-dinitrobenzene (1,3-DNB) impurities. The latter two compounds, being more volatile, have been reported to slowly leak through land mine covers and permeate the soil under which they are located, thus serving as potential indicators for buried land mines. We report on the construction of genetically engineered Escherichia coli bioreporter strains for the detection of these compounds, based on a genetic fusion between two gene promoters, yqjF and ybiJ, to either the green fluorescent protein gene GFPmut2 or to Photorhabdus luminescens bioluminescence luxCDABE genes. These two gene promoters were identified by exposing to 2,4-DNT a comprehensive library of about 2,000 E. coli reporter strains, each harboring a different E. coli gene promoter controlling a fluorescent protein reporter gene. Both reporter strains detected 2,4-DNT in an aqueous solution as well as in vapor form or when buried in soil. Performance of the yqjF-based sensor was significantly improved in terms of detection threshold, response time, and signal intensity, following two rounds of random mutagenesis in the promoter region. Both yqjF-based and ybiJ-based reporters were also induced by 2,4,6-TNT and 1,3-DNB. It was further demonstrated that both 2,4,6-TNT and 2,4-DNT are metabolized by E. coli and that the actual induction of both yqjF and ybiJ is caused by yet unidentified degradation products. This is the first demonstration of an E. coli whole-cell sensor strain for 2,4-DNT and 2,4,6-TNT, constructed using its own endogenous sensing elements. PMID:23615740

Yagur-Kroll, Sharon; Lalush, Chaim; Rosen, Rachel; Bachar, Neta; Moskovitz, Yaara; Belkin, Shimshon

2014-01-01

379

40 CFR 180.1301 - Escherichia coli O157:H7 specific bacteriophages; temporary exemption from the requirement of a...  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Escherichia coli O157:H7 specific bacteriophages...Tolerances § 180.1301 Escherichia coli O157:H7 specific bacteriophages...bacteriophages that are specific to Escherichia coli O157:H7,...

2013-07-01

380

40 CFR 180.1301 - Escherichia coli O157:H7 specific bacteriophages; temporary exemption from the requirement of a...  

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 false Escherichia coli O157:H7 specific bacteriophages...Tolerances § 180.1301 Escherichia coli O157:H7 specific bacteriophages...bacteriophages that are specific to Escherichia coli O157:H7,...

2012-07-01

381

40 CFR 180.1301 - Escherichia coli O157:H7 specific bacteriophages; temporary exemption from the requirement of a...  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 false Escherichia coli O157:H7 specific bacteriophages...Tolerances § 180.1301 Escherichia coli O157:H7 specific bacteriophages...bacteriophages that are specific to Escherichia coli O157:H7,...

2011-07-01

382

A Theoretical Interpretation of the Transient Sialic Acid Toxicity of a nanR Mutant of Escherichia coli  

E-print Network

Available online 7 November 2007 This article reports on experimental evidence that an Escherichia coli nan rights reserved. Edited by J. Kam Keywords: Escherichia coli; N-Acetylneuraminic acid; GlcNAc-6P toxicity bacteria that colonize animal hosts, even though some, such as Escherichia coli, lack a sialidase and hence

Kent, University of

383

Abstract The Escherichia coli Tat protein export path-way transports folded proteins synthesized with N-termi-  

E-print Network

Abstract The Escherichia coli Tat protein export path- way transports folded proteins synthesized that allowed export of the modified TorA pre- cursors. Keywords Escherichia coli · Tat protein export pathway for suppressors of Escherichia coli Tat signal peptide mutations establishes a critical role for the second

Palmer, Tracy

384

The diffusive influx and carrier efflux have a strong effect on the bistability of the lac operon in Escherichia coli  

E-print Network

in Escherichia coli Jason T. Noel a , Sergei S. Pilyugin b , Atul Narang c,Ã? a Department of Chemical Engineering of Escherichia coli exhibits bistability. Most models in the literature assume that the inducer enters the cell of lac bistability during growth of Escherichia coli K12 MG1655 on TMG and succinate/glucose. To this end

Pilyugin, Sergei S.

385

Inhibitory Mechanism of Escherichia coli RelE-RelB Toxin-Antitoxin Module Involves a Helix Displacement Near  

E-print Network

, Piscataway, New Jersey 08854-5635 In Escherichia coli, RelE toxin participates in growth arrest and cellInhibitory Mechanism of Escherichia coli RelE-RelB Toxin-Antitoxin Module Involves a Helix- tinct from the ribosome-independent mechanism of MazF. Even though the functionality of Escherichia coli

Ikura, Mitsuhiko

386

Characterization of interactions between Escherichia coli O157:H7 with epiphytic bacteria in vitro and on spinach leaf surfaces  

E-print Network

Characterization of interactions between Escherichia coli O157:H7 with epiphytic bacteria in vitro Escherichia coli O157:H7 Antagonism This study characterized the types of interactions between Escherichia for their ability to inhibit or to enhance the growth of E. coli O157:H7 in vitro and on spinach leaf surfaces

Falkinham, Joseph

387

Redesigning Escherichia coli Metabolism for Anaerobic Production of Isobutanol?†  

PubMed Central

Fermentation enables the production of reduced metabolites, such as the biofuels ethanol and butanol, from fermentable sugars. This work demonstrates a general approach for designing and constructing a production host that uses a heterologous pathway as an obligately fermentative pathway to produce reduced metabolites, specifically, the biofuel isobutanol. Elementary mode analysis was applied to design an Escherichia coli strain optimized for isobutanol production under strictly anaerobic conditions. The central metabolism of E. coli was decomposed into 38,219 functional, unique, and elementary modes (EMs). The model predictions revealed that during anaerobic growth E. coli cannot produce isobutanol as the sole fermentative product. By deleting 7 chromosomal genes, the total 38,219 EMs were constrained to 12 EMs, 6 of which can produce high yields of isobutanol in a range from 0.29 to 0.41 g isobutanol/g glucose under anaerobic conditions. The remaining 6 EMs rely primarily on the pyruvate dehydrogenase enzyme complex (PDHC) and are typically inhibited under anaerobic conditions. The redesigned E. coli strain was constrained to employ the anaerobic isobutanol pathways through deletion of 7 chromosomal genes, addition of 2 heterologous genes, and overexpression of 5 genes. Here we present the design, construction, and characterization of an isobutanol-producing E. coli strain to illustrate the approach. The model predictions are evaluated in relation to experimental data and strategies proposed to improve anaerobic isobutanol production. We also show that the endogenous alcohol/aldehyde dehydrogenase AdhE is the key enzyme responsible for the production of isobutanol and ethanol under anaerobic conditions. The glycolytic flux can be controlled to regulate the ratio of isobutanol to ethanol production. PMID:21642415

Trinh, Cong T.; Li, Johnny; Blanch, Harvey W.; Clark, Douglas S.

2011-01-01

388

Fimbrial adhesins produced by atypical enteropathogenic Escherichia coli strains.  

PubMed

Atypical enteropathogenic Escherichia coli (aEPEC) has emerged as a significant cause of pediatric diarrhea worldwide; however, information regarding its adherence mechanisms to the human gut mucosa is lacking. In this study, we investigated the prevalence of several (fimA, ecpA, csgA, elfA, and hcpA) fimbrial genes in 71 aEPEC strains isolated from children with diarrhea (54 strains) and healthy individuals (17 strains) in Brazil and Australia by PCR. These genes are associated with adhesion and/or biofilm formation of pathogenic and commensal E. coli. Here, the most prevalent fimbrial genes found, in descending order, were hcpA (98.6%), ecpA (86%), fimA (76%), elfA (72%), and csgA (19.7%). Phenotypic expression of pili in aEPEC strains was assessed by several approaches. We were not able to detect the hemorrhagic coli pilus (HCP) or the E. coli laminin-binding fimbriae (ELF) in these strains by using immunofluorescence. Type 1 pili and curli were detected in 59% (by yeast agglutination) and 2.8% (by Congo red binding and immunofluorescence) of the strains, respectively. The E. coli common pilus (ECP) was evidenced in 36.6% of the strains on bacteria adhering to HeLa cells by immunofluorescence, suggesting that ECP could play an important role in cell adherence for some aEPEC strains. This study highlights the complex nature of the adherence mechanisms of aEPEC strains involving the coordinated function of fimbrial (e.g., ECP) and nonfimbrial (e.g., intimin) adhesins and indicates that these strains bear several pilus operons that could potentially be expressed in different niches favoring colonization and survival in and outside the host. PMID:21926222

Hernandes, Rodrigo T; Velsko, Irina; Sampaio, Suely C F; Elias, Waldir P; Robins-Browne, Roy M; Gomes, Tânia A T; Girón, Jorge A

2011-12-01

389

F'-plasmid transfer from Escherichia coli to Pseudomonas fluorescens.  

PubMed Central

Various F' plasmids of Escherichia coli K-12 could be transferred into mutants of the soil strain 6.2, classified herein as a Pseudomonas fluorescens biotype IV. This strain was previously found to receive Flac plasmid (N. Datta and R.W. Hedges, J. Gen Microbiol. 70:453-460, 1972). ilv, leu, met, arg, and his auxotrophs were complemented by plasmids carrying isofunctional genes; trp mutants were not complemented or were very poorly complemented. The frequency of transfer was 10(-5). Subsequent transfer into other P. fluorescens recipients was of the same order of magnitude. Some transconjugants were unable to act as donors, and these did not lose the received information if subcultured on nonselective media. Use of F' plasmids helped to discriminate metabolic blocks in P. fluorescens. In particular, metA, metB, and argH mutants were so distinguished. In addition, F131 plasmid carrying the his operon and a supD mutation could partially relieve the auxotrophy of thr, ilv, and metA13 mutants, suggesting functional expression of E. coli tRNA in P. fluorescens. In P. fluorescens metA Rifr mutants carrying the F110 plasmid, which carried the E. coli metA gene and the E. coli rifs allele, sensitivity to rifampin was found to be dominant at least temporarily over resistance. This suggests interaction of E. coli and P. fluorescens subunits of RNA polymerase. his mutations were also complemented by composite P plasmids containing the his-nif region of Klebsiella pneumoniae (plasmids FN68 and RP41). nif expression could be detected by acetylene reduction in some his+ transconjugants. The frequency of transfer of these P plasmids was 5 X 10(-4). PMID:97267

Mergeay, M; Gerits, J

1978-01-01

390

Application of R-plasmid DNA’s from Escherichia coli minicells in genetic transformation  

Microsoft Academic Search

Components of minicell lyzatesof Escherichia coli P678-54 (Rldrd19) andEscherichia col P678-54 (R6K) were visualized in an electron microscope and used for the transformation ofEscherichia coli JC7623. The frequency of the resulting transformants (of the order of 10?6 %) was not appreciably influenced by the manner of lyzate preparation. The presence of covalently closed circular DNA was\\u000a detected in two different

J. Nešvera; J. Hochmannová; J. Štokrová

1978-01-01

391

A bioluminescent sensor for high throughput toxicity classification.  

PubMed

A high throughput toxicity monitoring and classification biosensor system has been successfully developed using four immobilized bioluminescent Escherichia coli strains, DPD2511, DPD2540, DPD2794 and TV1061, which have plasmids bearing a fusion of a specific promoter to the luxCDABE operon. The bioluminescence of DPD2511 increases in the presence of oxidative damage, DPD2540 by membrane damage, DPD2794 by DNA damage and TV1061 by protein damage. In the developed biosensor these strains are immobilized in a single 96 well plate using an LB-agar matrix, and are able to detect the toxicities of hydrogen peroxide, phenol and mitomycin C in water samples. As the concentration of each chemical was increased, the bioluminescence levels from the corresponding wells, containing either DPD2511, DPD2540, DPD2794 or TV1061, increased. This increase in bioluminescence followed a dose dependent response to the toxic chemicals within a specific concentration range. In particular, each test requires only 4 h to give clear bioluminescent response signature. Storage of the biosensor at 4 degrees C for 2 weeks caused no change in its dose-dependent response. The fast and easy detection of oxidative, membrane, protein and DNA damaging agents in aqueous environments is possible due to the high throughput capability of this biosensor. PMID:12782464

Kim, Byoung Chan; Gu, Man Bock

2003-08-01

392

FRQUENCE DE ESCHERICHIA COLI ENTROPATHOGNE K99+ ST+ ET DU ROTAVIRUS DANS LES DIARRHES NONATALES  

E-print Network

FR�QUENCE DE ESCHERICHIA COLI ENT�ROPATHOG�NE K99+ ST+ ET DU ROTAVIRUS DANS LES DIARRH�ES variée et complexe. Les trois, agents les plus fréquemment invo- qués sont Escherichia coli died. On the first visit, rota- virus was found in faeces of 11 diarrhoeic calves and E. coli K99+ ST

Paris-Sud XI, Université de

393

Escherichia coli: a brief review of diarrheagenic pathotypes and their role in diarrheal diseases in Iran  

PubMed Central

Diarrheagenic Escherichia coli have developed different strategies for establishment of infection in their host. Understanding these pathogenic mechanisms has led to the development of specific diagnostic tools for identification and categorization of E. coli strains into different pathotypes. This review aims to provide an overview of the various categories of diarrheagenic Escherichia coli and the data obtained in Iran pertaining to these pathotypes. PMID:23066484

Jafari, A; Aslani, MM; Bouzari, S

2012-01-01

394

Opposite effects of cefoperazone and ceftazidime on S-ribosylhomocysteine lyase/autoinducer-2 quorum sensing and biofilm formation by an Escherichia coli clinical isolate  

PubMed Central

To investigate the effects of subminimum inhibitory concentrations of cephalosporins on bacterial biofilm formation, the biofilm production of 52 Escherichia (E.) coli strains was examined following treatment with cephalosporin compounds at 1/4 minimum inhibitory concentrations (MICs). Ceftazidime (CAZ) inhibited biofilm formation in seven isolates, while cefoperazone (CFP) enhanced biofilm formation in 18 isolates. Biofilm formation of E. coli E42 was inhibited by CAZ and induced by CFP. Therefore, using reverse transcription-polymerase chain reaction, the expression of the biofilm-modulating genes of this isolate was investigated. To monitor the production of the autoinducer of quorum sensing in E. coli, autoinducer-2 (AI-2) production was detected by measuring the bioluminescence response of Vibrio harveyi BB170. Antisense oligonucleotides (AS-ODNs) targeting S-ribosylhomocysteine lyase (luxS) inhibited the expression of the luxS gene in E. coli. CAZ at 1/4 MIC reduced luxS mRNA levels and the production of AI-2, whereas CFP at 1/4 MIC had the opposite effect. AS-ODNs targeting luxS significantly decreased the aforementioned inhibitory effects of CAZ and the induction effects of CFP on E. coli biofilm formation. Therefore, biofilm formation by the E. coli clinical isolate E42 was evoked by CFP but attenuated by CAZ at sub-MICs, via a luxS/AI-2-based quorum sensing system. PMID:25189202

SHI, HUI-QING; SUN, FENG-JUN; CHEN, JIAN-HONG; YONG, XIAO-LAN; OU, QIAN-YI; FENG, WEI; XIA, PEI-YUAN

2014-01-01

395

Conjugation between two Escherichia coli strains and between Escherichia coli (donor) and Azospirillum brasilense (recipient) in the presence of various herbicides  

Microsoft Academic Search

The effects of various herbicides on conjugation (transfer of RP4 plasmid) between two strains of Escherichia coli and between E. coli (donor) and Azospirillum brasilense (recipient) were studied. Prior to the conjugation experiment, the growth of these bacteria in the presence of herbicides was examined. It was observed that except methyl viologen none of these herbicides exert any inhibitory effect

D. Gadkari

1991-01-01

396

Preharvest Evaluation of Coliforms, Escherichia coli, Salmonella, and Escherichia coli O157:H7 in Organic and Conventional Produce Grown by Minnesota Farmers  

Microsoft Academic Search

Microbiological analyses of fresh fruits and vegetables produced by organic and conventional farmers in Minnesota were conducted to determine the coliform count and the prevalence of Escherichia coli, Salmonella, and E. coli O157:H7. A total of 476 and 129 produce samples were collected from 32 organic and 8 conventional farms, respectively. The samples included tomatoes, leafy greens, lettuce, green peppers,

AVIK MUKHERJEE; DORINDA SPEH; ELIZABETH DYCK; FRANCISCO DIEZ-GONZALEZ

397

Microaerobic conversion of glycerol to ethanol in Escherichia coli.  

PubMed

Glycerol has become a desirable feedstock for the production of fuels and chemicals due to its availability and low price, but many barriers to commercialization remain. Previous investigators have made significant improvements in the yield of ethanol from glycerol. We have developed a fermentation process for the efficient microaerobic conversion of glycerol to ethanol by Escherichia coli that presents solutions to several other barriers to commercialization: rate, titer, specific productivity, use of inducers, use of antibiotics, and safety. To increase the rate, titer, and specific productivity to commercially relevant levels, we constructed a plasmid that overexpressed glycerol uptake genes dhaKLM, gldA, and glpK, as well as the ethanol pathway gene adhE. To eliminate the cost of inducers and antibiotics from the fermentation, we used the adhE and icd promoters from E. coli in our plasmid, and we implemented glycerol addiction to retain the plasmid. To address the safety issue of off-gas flammability, we optimized the fermentation process with reduced-oxygen sparge gas to ensure that the off-gas remained nonflammable. These advances represent significant progress toward the commercialization of an E. coli-based glycerol-to-ethanol process. PMID:24584248

Wong, Matthew S; Li, Mai; Black, Ryan W; Le, Thao Q; Puthli, Sharon; Campbell, Paul; Monticello, Daniel J

2014-05-01

398

Identification of Diarrheagenic Escherichia coli Strains from Avian Organic Fertilizers  

PubMed Central

The Brazilian poultry industry generates large amounts of organic waste, such as chicken litter, which is often used in agriculture. Among the bacteria present in organic fertilizer are members of the Enterobacteriaceae family. The objective of this study was to detect the presence of diarrheagenic Escherichia coli (DEC) strains in avian organic fertilizer, and assess the potential damage they can cause in humans due to antimicrobial resistance. The presence of DEC pathotypes and phylogenetic groups were detected by multiplex-PCR. Phenotypic assays, such as tests for adhesion, cytotoxicity activity, biofilm formation and especially antimicrobial susceptibility, were performed. Fifteen DEC strains from 64 E. coli were isolated. Among these, four strains were classified as enteropathogenic (EPEC; 6.2%), three strains as Shiga toxin-producing (STEC; 4.7%), 10 strains as enteroaggregative (EAEC; 12.5%), but two of these harbored the eaeA gene too. The low number of isolated strains was most likely due to the composting process, which reduces the number of microorganisms. These strains were able to adhere to HEp-2 and HeLa cells and produce Shiga-toxins and biofilms; in addition, some of the strains showed antimicrobial resistance, which indicates a risk of the transfer of resistance genes to human E. coli. These results showed that DEC strains isolated from avian organic fertilizers can cause human infections. PMID:25170683

Puño-Sarmiento, Juan; Gazal, Luis Eduardo; Medeiros, Leonardo P.; Nishio, Erick K.; Kobayashi, Renata K. T.; Nakazato, Gerson

2014-01-01

399

Functional expression of plant acetolactate synthase genes in Escherichia coli  

PubMed Central

Acetolactate synthase (ALS; EC 4.1.3.18) is the first common enzyme in the biosynthetic pathways leading to leucine, isoleucine, and valine. It is the target enzyme for three classes of structurally unrelated herbicides, the sulfonylureas, the imidazolinones, and the triazolopyrimidines. A cloned ALS gene from the small cruciferous plant Arabidopsis thaliana has been fused to bacterial transcription/translation signals and the resulting plasmid has been used to transform Escherichia coli. The cloned plant gene, which includes sequences encoding the chloroplast transit peptide, is functionally expressed in the bacteria. It is able to complement genetically a strain of E. coli that lacks endogenous ALS activity. An ALS gene cloned from a line of Arabidopsis previously shown to be resistant to sulfonylurea herbicides has been similarly expressed in E. coli. The herbicide-resistance phenotype is expressed in the bacteria, as assayed by both enzyme activity and the ability to grow in the presence of herbicides. This system has been useful for purifying substantial amounts of the plant enzyme, for studying the sequence parameters involved in subcellular protein localization, and for characterizing the interactions that occur between ALS and its various inhibitors. Images PMID:16594052

Smith, Julie K.; Schloss, John V.; Mazur, Barbara J.

1989-01-01

400

Comprehensive Mapping of the Escherichia coli Flagellar Regulatory Network.  

PubMed

Flagellar synthesis is a highly regulated process in all motile bacteria. In Escherichia coli and related species, the transcription factor FlhDC is the master regulator of a multi-tiered transcription network. FlhDC activates transcription of a number of genes, including some flagellar genes and the gene encoding the alternative Sigma factor FliA. Genes whose expression is required late in flagellar assembly are primarily transcribed by FliA, imparting temporal regulation of transcription and coupling expression to flagellar assembly. In this study, we use ChIP-seq and RNA-seq to comprehensively map the E. coli FlhDC and FliA regulons. We define a surprisingly restricted FlhDC regulon, including two novel regulated targets and two binding sites not associated with detectable regulation of surrounding genes. In contrast, we greatly expand the known FliA regulon. Surprisingly, 30 of the 52 FliA binding sites are located inside genes. Two of these intragenic promoters are associated with detectable noncoding RNAs, while the others either produce highly unstable RNAs or are inactive under these conditions. Together, our data redefine the E. coli flagellar regulatory network, and provide new insight into the temporal orchestration of gene expression that coordinates the flagellar assembly process. PMID:25275371

Fitzgerald, Devon M; Bonocora, Richard P; Wade, Joseph T

2014-10-01

401

Characterization of Pyruvate Uptake in Escherichia coli K-12  

PubMed Central

The monocarboxylate pyruvate is an important metabolite and can serve as sole carbon source for Escherichia coli. Although specific pyruvate transporters have been identified in two bacterial species, pyruvate transport is not well understood in E. coli. In the present study, pyruvate transport was investigated under different growth conditions. The transport of pyruvate shows specific activities depending on the growth substrate used as sole carbon source, suggesting the existence of at least two systems for pyruvate uptake: i) one inducible system and probably highly specific for pyruvate and ii) one system active under non-induced conditions. Using the toxic pyruvate analog 3-fluoropyruvate, a mutant was isolated unable to grow on and transport pyruvate. Further investigation revealed that a revertant selected for growth on pyruvate regained the inducible pyruvate transport activity. Characterization of pyruvate excretion showed that the pyruvate transport negative mutant accumulated pyruvate in the growth medium suggesting an additional transport system for pyruvate excretion. The here presented data give valuable insight into the pyruvate metabolism and transport of E. coli suggesting the presence of at least two uptake systems and one excretion system to balance the intracellular level of pyruvate. PMID:23818977

Kreth, Jens; Lengeler, Joseph W.; Jahreis, Knut

2013-01-01

402

Identification of Diarrheagenic Escherichia coli Strains from Avian Organic Fertilizers.  

PubMed

The Brazilian poultry industry generates large amounts of organic waste, such as chicken litter, which is often used in agriculture. Among the bacteria present in organic fertilizer are members of the Enterobacteriaceae family. The objective of this study was to detect the presence of diarrheagenic Escherichia coli (DEC) strains in avian organic fertilizer, and assess the potential damage they can cause in humans due to antimicrobial resistance. The presence of DEC pathotypes and phylogenetic groups were detected by multiplex-PCR. Phenotypic assays, such as tests for adhesion, cytotoxicity activity, biofilm formation and especially antimicrobial susceptibility, were performed. Fifteen DEC strains from 64 E. coli were isolated. Among these, four strains were classified as enteropathogenic (EPEC; 6.2%), three strains as Shiga toxin-producing (STEC; 4.7%), 10 strains as enteroaggregative (EAEC; 12.5%), but two of these harbored the eaeA gene too. The low number of isolated strains was most likely due to the composting process, which reduces the number of microorganisms. These strains were able to adhere to HEp-2 and HeLa cells and produce Shiga-toxins and biofilms; in addition, some of the strains showed antimicrobial resistance, which indicates a risk of the transfer of resistance genes to human E. coli. These results showed that DEC strains isolated from avian organic fertilizers can cause human infections. PMID:25170683

Puño-Sarmiento, Juan; Gazal, Luis Eduardo; Medeiros, Leonardo P; Nishio, Erick K; Kobayashi, Renata K T; Nakazato, Gerson

2014-01-01

403

Colibri: a functional data base for the Escherichia coli genome.  

PubMed Central

Several data libraries have been created to organize all the data obtained worldwide about the Escherichia coli genome. Because the known data now amount to more than 40% of the whole genome sequence, it has become necessary to organize the data in such a way that appropriate procedures can associate knowledge produced by experiments about each gene to its position on the chromosome and its relation to other relevant genes, for example. In addition, global properties of genes, affected by the introduction of new entries, should be present as appropriate description fields. A data base, implemented on Macintosh by using the data base management system 4th Dimension, is described. It is constructed around a core constituted by known contigs of E. coli sequences and links data collected in general libraries (unmodified) to data associated with evolving knowledge (with modifiable fields). Biologically significant results obtained through the coupling of appropriate procedures (learning or statistical data analysis) are presented. The data base is available through a 4th Dimension runtime and through FTP on Internet. It has been regularly updated and will be systematically linked to other E. coli data bases (M. Kroger, R. Wahl, G. Schachtel, and P. Rice, Nucleic Acids Res. 20(Suppl.):2119-2144, 1992; K. E. Rudd, W. Miller, C. Werner, J. Ostell, C. Tolstoshev, and S. G. Satterfield, Nucleic Acids Res. 19:637-647, 1991) in the near future. Images PMID:8246843

Medigue, C; Viari, A; Henaut, A; Danchin, A

1993-01-01

404

Neisseria gonorrhoeae prepilin export studied in Escherichia coli.  

PubMed Central

The pilE gene of Neisseria gonorrhoeae MS11 and a series of pilE-phoA gene fusions were expressed in Escherichia coli. The PhoA hybrid proteins were shown to be located in the membrane fraction of the cells, and the prepilin product of the pilE gene was shown to be located exclusively in the cytoplasmic membrane. Analysis of the prepilin-PhoA hybrids showed that the first 20 residues of prepilin can function as an efficient export (signal) sequence. This segment of prepilin includes an unbroken sequence of 8 hydrophobic or neutral residues that form the N-terminal half of a 16-residue hydrophobic region of prepilin. Neither prepilin nor the prepilin-PhoA hybrids were processed by E. coli leader peptidase despite the presence of two consensus cleavage sites for this enzyme just after this hydrophobic region. Comparisons of the specific molecular activities of the four prepilin-PhoA hybrids and analysis of their susceptibility to proteolysis by trypsin and proteinase K in spheroplasts allow us to propose two models for the topology of prepilin in the E. coli cytoplasmic membrane. The bulk of the evidence supports the simplest of the two models, in which prepilin is anchored in the membrane solely by the N-terminal hydrophobic domain, with the extreme N terminus facing the cytoplasm and the longer C terminus facing the periplasm. Images FIG. 2 FIG. 4 FIG. 5 FIG. 6 PMID:1938955

Dupuy, B; Taha, M K; Pugsley, A P; Marchal, C

1991-01-01

405

Increased Survival of Antibiotic-Resistant Escherichia coli inside Macrophages  

PubMed Central

Mutations causing antibiotic resistance usually incur a fitness cost in the absence of antibiotics. The magnitude of such costs is known to vary with the environment. Little is known about the fitness effects of antibiotic resistance mutations when bacteria confront the host's immune system. Here, we study the fitness effects of mutations in the rpoB, rpsL, and gyrA genes, which confer resistance to rifampin, streptomycin, and nalidixic acid, respectively. These antibiotics are frequently used in the treatment of bacterial infections. We measured two important fitness traits—growth rate and survival ability—of 12 Escherichia coli K-12 strains, each carrying a single resistance mutation, in the presence of macrophages. Strikingly, we found that 67% of the mutants survived better than the susceptible bacteria in the intracellular niche of the phagocytic cells. In particular, all E. coli streptomycin-resistant mutants exhibited an intracellular advantage. On the other hand, 42% of the mutants incurred a high fitness cost when the bacteria were allowed to divide outside of macrophages. This study shows that single nonsynonymous changes affecting fundamental processes in the cell can contribute to prolonged survival of E. coli in the context of an infection. PMID:23089747

Miskinyte, Migla

2013-01-01

406

Biofilm and fluoroquinolone resistance of canine Escherichia coli uropathogenic isolates  

PubMed Central

Background Escherichia coli is the most common uropathogen involved in urinary tract infection (UTI). Virulence of strains may differ, and may be enhanced by antimicrobial resistance and biofilm formation, resulting in increased morbidity and recurrent infections. The aim of this study was to evaluate the in vitro biofilm forming capacity of E. coli isolates from dogs with UTI, by using fluorescent in situ hybridization, and its association with virulence genes and antimicrobial resistance. Findings The proportion of biofilm-producing isolates significantly increased with the length of incubation time (P??0.05), but was significantly associated with afa, aer and the ?-lactamase genes (P?coli isolates from dogs with UTI. Biofilm formation may contribute to UTI treatment failure in dogs, through the development of bacterial reservoirs inside bladder cells, allowing them to overcome host immune defenses and to establish recurrent infections. PMID:25099929

2014-01-01

407

Characterization of the YdeO Regulon in Escherichia coli  

PubMed Central

Enterobacteria are able to survive under stressful conditions within animals, such as acidic conditions in the stomach, bile salts during transfer to the intestine and anaerobic conditions within the intestine. The glutamate-dependent (GAD) system plays a major role in acid resistance in Escherichia coli, and expression of the GAD system is controlled by the regulatory cascade consisting of EvgAS > YdeO > GadE. To understand the YdeO regulon in vivo, we used ChIP-chip to interrogate the E. coli genome for candidate YdeO binding sites. All of the seven operons identified by ChIP-chip as being potentially regulated by YdeO were confirmed as being under the direct control of YdeO using RT-qPCR, EMSA, DNaseI-footprinting and reporter assays. Within this YdeO regulon, we identified four stress-response transcription factors, DctR, NhaR, GadE, and GadW and enzymes for anaerobic respiration. Both GadE and GadW are involved in regulation of the GAD system and NhaR is an activator for the sodium/proton antiporter gene. In conjunction with co-transcribed Slp, DctR is involved in protection against metabolic endoproducts under acidic conditions. Taken all together, we suggest that YdeO is a key regulator of E. coli survival in both acidic and anaerobic conditions. PMID:25375160

Yamanaka, Yuki; Oshima, Taku; Ishihama, Akira; Yamamoto, Kaneyoshi

2014-01-01

408

Survival of Escherichia coli and Salmonella spp. in estuarine environments.  

PubMed

Survival of Escherichia coli and Salmonella spp. in estuarine waters was compared over a variety of seasonal temperatures during in situ exposure in diffusion chambers. Sublethal stress was measured by both selective-versus-resuscitative enumeration procedures and an electrochemical detection method. E. coli and Salmonella spp. test suspensions, prepared to minimize sublethal injury, were exposed in a shallow tidal creek and at a site 7.1 km further downriver. Bacterial die-off and sublethal stress in filtered estuarine water were inversely related to water temperature. Salmonella spp. populations exhibited significantly less die-off and stress than did E. coli at water temperatures of less than 10 degrees C. Although the most pronounced reductions (ca. 3 log units) in test bacteria occurred during seasonally warm temperatures in the presence of the autochthonous microbiota, 10(2) to 10(4) test cells per ml remained after 2 weeks of exposure to temperatures of greater than 15 degrees C. Reductions in test bacteria were associated with increases in the densities of microflagellates and plaque-forming microorganisms. These studies demonstrated the survival potential of enteric bacteria in estuarine waters and showed that survival was a function of interacting biological and physical factors. PMID:3066291

Rhodes, M W; Kator, H

1988-12-01

409

The binary protein-protein interaction landscape of Escherichia coli  

PubMed Central

Efforts to map the Escherichia coli interactome have identified several hundred macromolecular complexes, but direct binary protein-protein interactions (PPIs) have not been surveyed on a large scale. Here we performed yeast two-hybrid screens of 3,305 baits against 3,606 preys (~70% of the E. coli proteome) in duplicate to generate a map of 2,234 interactions, approximately doubling the number of known binary PPIs in E. coli. Integration of binary PPIs and genetic interactions revealed functional dependencies among components involved in cellular processes, including envelope integrity, flagellum assembly and protein quality control. Many of the binary interactions that could be mapped within multi-protein complexes were informative regarding internal topology and indicated that interactions within complexes are significantly more conserved than those interactions connecting different complexes. This resource will be useful for inferring bacterial gene function and provides a draft reference of the basic physical wiring network of this evolutionarily significant model microbe. PMID:24561554

Rajagopala, Seesandra V.; Vlasblom, James; Arnold, Roland; Franca-Koh, Jonathan; Pakala, Suman B.; Phanse, Sadhna; Ceol, Arnaud; Hauser, Roman; Siszler, Gabriella; Wuchty, Stefan; Emili, Andrew; Babu, Mohan; Aloy, Patrick; Pieper, Rembert; Uetz, Peter

2014-01-01

410

Global Functional Atlas of Escherichia coli Encompassing Previously Uncharacterized Proteins  

PubMed Central

One-third of the 4,225 protein-coding genes of Escherichia coli K-12 remain functionally unannotated (orphans). Many map to distant clades such as Archaea, suggesting involvement in basic prokaryotic traits, whereas others appear restricted to E. coli, including pathogenic strains. To elucidate the orphans' biological roles, we performed an extensive proteomic survey using affinity-tagged E. coli strains and generated comprehensive genomic context inferences to derive a high-confidence compendium for virtually the entire proteome consisting of 5,993 putative physical interactions and 74,776 putative functional associations, most of which are novel. Clustering of the respective probabilistic networks revealed putative orphan membership in discrete multiprotein complexes and functional modules together with annotated gene products, whereas a machine-learning strategy based on network integration implicated the orphans in specific biological processes. We provide additional experimental evidence supporting orphan participation in protein synthesis, amino acid metabolism, biofilm formation, motility, and assembly of the bacterial cell envelope. This resource provides a “systems-wide” functional blueprint of a model microbe, with insights into the biological and evolutionary significance of previously uncharacterized proteins. PMID:19402753

Yang, Wenhong; Pogoutse, Oxana; Guo, Xinghua; Phanse, Sadhna; Wong, Peter; Chandran, Shamanta; Christopoulos, Constantine; Nazarians-Armavil, Anaies; Nasseri, Negin Karimi; Musso, Gabriel; Ali, Mehrab; Nazemof, Nazila; Eroukova, Veronika; Golshani, Ashkan; Paccanaro, Alberto; Greenblatt, Jack F; Moreno-Hagelsieb, Gabriel; Emili, Andrew

2009-01-01

411

Reduction of aerobic acetate production by Escherichia coli.  

PubMed Central

Acetate excretion by Escherichia coli during aerobic growth on glucose is a major obstacle to enhanced recombinant protein production. We report here that the fraction of carbon flux through the anaplerotic pathways is one of the factors influencing acetate excretion. Flux analysis of E. coli central metabolic pathways predicts that increasing the fraction of carbon flux through the phosphoenolpyruvate carboxylase (PPC) pathway and the glyoxylate bypass reduces acetate production. We tested this prediction by overexpressing PPC and deregulating the glyoxylate bypass by using a fadR strain. Results show that the acetate yield by the fadR strain with PPC overexpression is decreased more than fourfold compared to the control, while the biomass yield is relatively unaffected. Apparently, the fraction of carbon flux through the anaplerotic pathways is one of the factors that influence acetate excretion. These results confirm the prediction of our flux analysis and further suggest that E. coli is not fully optimized for efficient utilization of glucose. PMID:9251207

Farmer, W R; Liao, J C

1997-01-01

412

Properties of a Clostridium thermocellum Endoglucanase Produced in Escherichia coli  

PubMed Central

A cellulase gene of Clostridium thermocellum was transferred to Escherichia coli by molecular cloning with bacteriophage lambda and plasmid vectors and shown to be indentical with the celA gene. The celA gene product was purified from extracts of plasmid-bearing E. coli cells by heat treatment and chromatography on DEAE-Trisacryl. It was characterized as a thermophilic endo-?-1,4-glucanase, the properties of which closely resemble those of endoglucanase A previously isolated from C. thermocellum supernatants. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis the enzyme purified from E. coli exhibited two protein bands with molecular weights of 49,000 and 52,000. It had a temperature optimum at 75°C and was stable for several hours at 60°C. Endoglucanase activity was optimal between pH 5.5 and 6.5. The enzyme was insensitive against end product inhibition by glucose and cellobiose and remarkably resistant to the denaturing effects of detergents and organic solvents. It was capable of degrading, in addition to cellulosic substrates, glucans with alternating ?-1,4 and ?-1,3 linkages such as barley ?-glucan and lichenan. PMID:16347088

Schwarz, Wolfgang H.; Grabnitz, Folke; Staudenbauer, Walter L.

1986-01-01

413

Microaerobic Conversion of Glycerol to Ethanol in Escherichia coli  

PubMed Central

Glycerol has become a desirable feedstock for the production of fuels and chemicals due to its availability and low price, but many barriers to commercialization remain. Previous investigators have made significant improvements in the yield of ethanol from glycerol. We have developed a fermentation process for the efficient microaerobic conversion of glycerol to ethanol by Escherichia coli that presents solutions to several other barriers to commercialization: rate, titer, specific productivity, use of inducers, use of antibiotics, and safety. To increase the rate, titer, and specific productivity to commercially relevant levels, we constructed a plasmid that overexpressed glycerol uptake genes dhaKLM, gldA, and glpK, as well as the ethanol pathway gene adhE. To eliminate the cost of inducers and antibiotics from the fermentation, we used the adhE and icd promoters from E. coli in our plasmid, and we implemented glycerol addiction to retain the plasmid. To address the safety issue of off-gas flammability, we optimized the fermentation process with reduced-oxygen sparge gas to ensure that the off-gas remained nonflammable. These advances represent significant progress toward the commercialization of an E. coli-based glycerol-to-ethanol process. PMID:24584248

Wong, Matthew S.; Li, Mai; Black, Ryan W.; Le, Thao Q.; Puthli, Sharon; Campbell, Paul

2014-01-01

414

Comprehensive Mapping of the Escherichia coli Flagellar Regulatory Network  

PubMed Central

Flagellar synthesis is a highly regulated process in all motile bacteria. In Escherichia coli and related species, the transcription factor FlhDC is the master regulator of a multi-tiered transcription network. FlhDC activates transcription of a number of genes, including some flagellar genes and the gene encoding the alternative Sigma factor FliA. Genes whose expression is required late in flagellar assembly are primarily transcribed by FliA, imparting temporal regulation of transcription and coupling expression to flagellar assembly. In this study, we use ChIP-seq and RNA-seq to comprehensively map the E. coli FlhDC and FliA regulons. We define a surprisingly restricted FlhDC regulon, including two novel regulated targets and two binding sites not associated with detectable regulation of surrounding genes. In contrast, we greatly expand the known FliA regulon. Surprisingly, 30 of the 52 FliA binding sites are located inside genes. Two of these intragenic promoters are associated with detectable noncoding RNAs, while the others either produce highly unstable RNAs or are inactive under these conditions. Together, our data redefine the E. coli flagellar regulatory network, and provide new insight into the temporal orchestration of gene expression that coordinates the flagellar assembly process. PMID:25275371

Fitzgerald, Devon M.; Bonocora, Richard P.; Wade, Joseph T.

2014-01-01

415

Comparison of the Small Molecule Metabolic Enzymes of Escherichia coli and Saccharomyces cerevisiae  

Microsoft Academic Search

The comparison of the small molecule metabolism pathways in Escherichia coli and Saccharomyces cerevisiae (yeast) shows that 271 enzymes are common to both organisms. These common enzymes involve 384 gene products in E. coli and 390 in yeast, which are between one half and two thirds of the gene products of small molecule metabolism in E. coli and yeast, respectively.

Oliver Jardine; Julian Gough; Cyrus Chothia; Sarah A. Teichmann

2002-01-01

416

High Rates of Escherichia coli Transmission between Livestock and Humans in Rural Uganda  

Microsoft Academic Search

Escherichia coli is a zoonotic bacterium that is important to both public health and livestock economics. To date, most studies of zoonotic E. coli transmission have been conducted in developed nations with industrial- ized agricultural economies. In this study, E. coli bacteria were collected from people and livestock in two communities in rural western Uganda in order to investigate patterns

Innocent B. Rwego; Thomas R. Gillespie; Gilbert Isabirye-Basuta; Tony L. Goldberg

417

Potential effect of cattle diets on the transmission of pathogenic Escherichia coli to humans  

Microsoft Academic Search

Grain feeding seems to promote the growth and acid resistance of Escherichia coli in fattening beef cattle, and acid-resistant E. coli are more likely to survive the human gastric stomach. When cattle were fed hay for only five days, the number and acid resistance of E. coli decreased dramatically.

James B. Russell; Francisco Diez-Gonzalez; Graeme N. Jarvis

2000-01-01

418

Escherichia coli, Salmonella, and Mycobacterium paratuberculosis in Wild European Starlings at a Kansas Cattle Feedlot  

Microsoft Academic Search

SUMMARY. The prevalence of Escherichia coli, Salmonella spp., and Mycobacterium avium subsp. paratuberculosis isolated from the feces of wild European starlings (Sturnus vulgaris) humanely trapped at a feedlot in central Kansas was assessed. All E. coli and Salmonella isolates recovered were tested for antimicrobial susceptibility using National Antimicrobial Resistance Monitoring System panels and the E. coli isolates were classified as

Shannon M. Gaukler; George M Linz; Julie S. Sherwood; Neil W Dyer; William J Bleier; Yvonne M Wannemuehler; Lisa K Nolan; Catherine M Logue

2009-01-01

419

Identification of Fecal Escherichia coli from Humans and Animals by Ribotyping  

Microsoft Academic Search

Fecal pollution of water resources is an environmental problem of increasing importance. Identification of individual host sources of fecal Escherichia coli, such as humans, pets, production animals, and wild animals, is prerequisite to formulation of remediation plans. Ribotyping has been used to distinguish fecal E. coli of human origin from pooled fecal E. coli isolates of nonhuman origin. We have

C. ANDREW CARSON; BRIAN L. SHEAR; MARK R. ELLERSIECK; AMHA ASFAW

2001-01-01

420

Chemical and gravity dependent factors affecting Escherichia coli lag phase termination  

E-print Network

concentration gradients. The organism used for this study was Escherichia coli ATCC 4157. Acetic acid was not found in the extracellular environment of E. coli at the end of lag phase. Lactic acid was found in the extracellular environment of E. coli...

Elms, Rene ?Davina

2012-06-07

421

Rotation of Escherichia coli F1-ATPase Hiroyuki Noji,* Katrin Hasler, Wolfgang Junge, Kazuhiko Kinosita, Jr.,*,  

E-print Network

were confirmed by DNA sequencing. Protein preparations. E. coli strain DK8 was transformed with pKH7) for the rotation assay was obtained by expression of the plasmid pKH7 in E. coli strain DK8. pKH7 was constructedRotation of Escherichia coli F1-ATPase Hiroyuki Noji,* Katrin Ha�sler, Wolfgang Junge, Kazuhiko

Junge, Wolfgang

422

Perpendicular planes of FtsZ arcs in spheroidal Escherichia coli cells Evelien Pasa  

E-print Network

dividing spheroidal E. coli that initiate secondary constrictions before separation [5]. Spheroids were]) was used. It was inserted in pBAD (from Invitrogene) and introduced into the thyA strain CR34 of E. coli [3Perpendicular planes of FtsZ arcs in spheroidal Escherichia coli cells Evelien Pasa , Monica Einavb

Zaritsky, Arieh

423

High Rates of Escherichia coli Transmission between Livestock and Humans in Rural Uganda  

Microsoft Academic Search

Escherichia coli is a zoonotic bacterium that is important to both public health and livestock economics. To date, most studies of zoonotic E. coli transmission have been conducted in developed nations with industrial- ized agricultural economies. In this study, E. coli bacteria were collected from people and livestock in two communities in rural western Uganda in order to investigate patterns

Innocent B. Rwego; Thomas R. Gillespie; Gilbert Isabirye-Basuta; Tony L. Goldberg

2008-01-01

424

Chemotactic-like response of Escherichia coli cells lacking the known chemotaxis machinery but  

E-print Network

Chemotactic-like response of Escherichia coli cells lacking the known chemotaxis machinery as well as other known attractants of E. Coli, glucose and, to a lesser extent, galactose, maltose concen- trations, act as repellents for wild-type E. coli ). Other tested repellents such as indole, Ni2þ

Fernando, Chrisantha

425

Modeling the chemotactic response of Escherichia coli to time-varying stimuli  

E-print Network

to predict E. coli chemotaxis responses to arbitrary temporal signals. This model of the receptor system pathway for Escherichia coli chemotaxis (see refs. 3­5 for recent reviews). However, such a simple temporal stimulus is unlikely to be the typical signal en- countered by E. coli cells in their natural

Shimizu, Tom

426

Secondary sigma Factor Controls Transcription of Flagellar and Chemotaxis Genes in Escherichia coli  

Microsoft Academic Search

The genes specifying chemotaxis, motility, and flagellar function in Escherichia coli are coordinately regulated and form a large and complex regulon. Despite the importance of these genes in controlling bacterial behavior, little is known of the molecular mechanisms that regulate their expression. We have identified a minor form of E. coli RNA polymerase that specifically transcribes several E. coli chemotaxis\\/flagellar

David N. Arnosti; Michael J. Chamberlin

1989-01-01

427

Mobilization of Escherichia coli R1 silver-resistance plasmid pJT1 by Tn5Mob into Escherichia coli C600  

Microsoft Academic Search

Summary Escherichia coli Rl is an Ag+-resistant strain that, as we have shown recently, harbours at least two large plasmids, pJT1 (83 kb) and pJT2 (77 kb). Tn5-Mob was introduced into theE. coli Rl host replicon via conjugation on membrane filters. The transfer functions of plasmid RP4-4 were provided in this process and Tn5-Mob clones mated withE. coli C600 yielded

Mary-Ellen Starodub; Jack T. Trevors

1990-01-01

428

Production of bioactive chicken follistatin315 in Escherichia coli.  

PubMed

Follistatin (FST) binds to myostatin (MSTN), a potent negative regulator of skeletal muscle growth. Inhibition of MSTN activity by FST treatment has shown to enhance muscle growth as well as ameliorate symptoms of muscular dystrophy in animal models, illustrating the potential of FST as an agent to enhance muscle growth in animal agriculture or to treat muscle wasting conditions or disease in humans. Therefore, we designed a study to produce biologically active recombinant chicken FST315 (chFST315) in an Escherichia coli host. Since FST contains multiple intramolecular disulfide bonds, we expressed chFST315 protein in either a system that utilizes a periplasmic expression strategy, or a genetically modified E. coli system (SHuffle strain) that is capable of disulfide bond formation in the cytoplasm. Periplasmic expression of chFST315 using the pMAL-p5x vector system, which was designed to express maltose-binding protein (MBP) fusion protein, failed to produce a soluble recombinant protein. However, cytoplasmic expression of chFST315 using pMAL-c5x vector in SHuffle E. coli strain resulted in a soluble expression of the recombinant protein (MBP-chFST315). Combination of heparin and amylose resin affinity chromatography yielded about 6 mg/L purified MBP-chFST315. The purified MBP-chFST315 showed binding affinity to MSTN and activin in a pull-down assay, as well as inhibited MSTN and activin activity in an in vitro reporter gene assay. In conclusion, results of the study demonstrate that for the first time a recombinant, biologically active FST molecule can be produced in a soluble form in E. coli. The ability to produce FST in a cost-effective system is expected to allow us to investigate the potentials of FST as an agent to improve skeletal muscle growth of meat producing animals via suppression of MSTN. PMID:25411099

Lee, Sang Beum; Choi, Rocky; Park, Sung Kwon; Kim, Yong Soo

2014-12-01

429

Regiospecific modifications of naringenin for astragalin production in Escherichia coli.  

PubMed

We report the production of astragalin (AST) from regiospecific modifications of naringenin (NRN) in Escherichia coli BL21(DE3). The exogenously supplied NRN was converted into dihydrokaempferol (DHK) and then kaempferol (KMF) in the presence of flavanone-3-hydroxylase (f3h) and flavonone synthase (fls1) from Arabidopsis thaliana, respectively. KMF was further modified to produce AST by 3-O-glucosylation utilizing the endogeneous UDP-glucose in presence of UGT78K1 from Glycine max. To increase the intracellular UDP-glucose concentration by channeling the carbon flux toward UDP-glucose at the branch point of glucose-6-phosphate (G6P), the chromosomal glucose phosphate isomerase (pgi) and D-glucose-6-phosphate dehydrogenase (zwf) were knocked-out in E. coli BL21(DE3). The two enzymes directly involved in the synthesis of UDP-glucose from G6P, phosphoglucomutase (nfa44530) from Nocardia farcinia and glucose-1-phosphate uridylyltransferase (galU) from E. coli K12 were overexpressed, which successfully diverted the carbon flow from glycolysis to the synthesis of UDP-glucose. Furthermore, to prevent the dissociation of UDP-glucose into UDP and glucose, the UDP-glucose hydrolase (ushA) was deleted. The E. coli ?pgi?zwf?ushA mutant harboring the UDP-glucose biosynthetic pathway and the aforementioned genes for the regiospecific glucosylation produced 109.3?mg/L (244?µM) of AST representing 48.8% conversion from 500?µM of NRN in 60?h without any supplementation of extracellular UDP-glucose. PMID:23568509

Malla, Sailesh; Pandey, Ramesh Prasad; Kim, Byung-Gee; Sohng, Jae Kyung

2013-09-01

430

Preventing Foodborne Illness: Escherichia coli 0157:H7  

NSDL National Science Digital Library

This two-page, Center for Disease Control brochure provides excellent summary information on what E. coli 0157:H7 is, why it is a problem, how it is spread, and includes information on symptoms, diagnosis, and treatment. Available in HTML or ASCII text, this is a good introduction to the subject. Escherichia coli refers to a diverse family of hundreds of bacteria, many of which are permanent residents of human intestines, serving a beneficial purpose in digestion. The potentially deadly strain that has received recent publicity was first described in 1982, and is known as E. coli O157:H7. This strain of the bacteria produces a substance known as Vero-cytotoxin, which can cause severe illness, characterized by bloody diarrhea and occasional kidney failure in children and the elderly. Symptoms normally appear between three to six days after ingestion of the bacteria. Most illness associated with E. coli has been traced to eating undercooked, contaminated ground beef, although it can also be transmitted via person-to-person contact, by eating raw milk, contaminated vegetables or apple cider, and by swimming in or drinking sewage-contaminated water. The organism lives in the intestine of healthy cattle, and meat can become contaminated during slaughter. Because grinding mixes the bacteria into the product, ground meats represent a greater threat than do whole cuts. Contaminated meat looks and smells normal. Raw milk can be contaminated from bacteria present on a cow's udder. It appears that even small amounts of this organism can cause severe illness.

1995-01-01

431

Atypical biogroups of Escherichia coli found in clinical specimens and description of Escherichia hermannii sp. nov.  

PubMed

DNA relatedness was used to define the biochemical boundaries of Escherichia coli. A large number of biochemically atypical strains were shown to belong to biogroups of E. coli. These included strains negative in reactions for indole, all three decarboxylases, D-mannitol, lactose, or methyl red and strains positive in reactions for H2S, urea, citrate, KCN, adonitol, myo-inositol, or phenylalanine deaminase. Frequency and source data are presented for these atypical E. coli biogroups. One group of KCN-positive, cellobiose-positive, yellow-pigmented strains was 84 to 91% interrelated but only 35 to 45% related to E. coli. The name Escherichia hermannii sp. nov. is proposed for this group of organisms that was formerly called Enteric Group 11 by the Enteric Section, Centers for Disease Control, Atlanta, GA. Twenty-nine strains of E. hermannii have been isolated in the United States from a variety of clinical sources, principally wounds, sputum, and stools. Three additional strains were isolated from food. E. hermannii strains are gram-negative, oxidase-negative, fermentative, motile rods. In addition to yellow pigment and positive KCN and cellobiose tests, the biochemical reactions characteristic of 32 strains of E. hermannii were as follows: gas from D-glucose, acid from D-glucose, maltose, D-xylose, L-arabinose, L-rhamnose, and D-mannitol; no acid from adonitol or inositol; variable acid production from lactose and sucrose; positive tests for indole, methyl red, and mucate; negative tests for Voges-Proskauer. Simmons citrate, H2S, urea, phenylalanine deaminase, and gelatin hydrolysis; negative or delayed test for L-lysine decarboxylase and negative test for L-arginine dihydrolase; and positive test for ornithine decarboxylase. E. hermannii strains were resistant to penicillin, ampicillin, and carbenicillin and sensitive to other commonly used antibiotics. Wounds account for almost 50% of human isolates of E. hermannii, followed by sputum or lung isolates (ca. 25%) and stool isolates (20%). PMID:7040466

Brenner, D J; Davis, B R; Steigerwalt, A G; Riddle, C F; McWhorter, A C; Allen, S D; Farmer, J J; Saitoh, Y; Fanning, G R

1982-04-01

432

Survival and alteration of the plasmid-containing microorganism Escherichia coli Z905/pPHL7 introduced into manmade closed aquatic microcosms  

NASA Astrophysics Data System (ADS)

It has been demonstrated that the transgenic microorganism Escherichia coli Z905/pPHL7 (Ap rLux +) can exist for a long time at an elevated concentration of mineral salts. The microorganism was introduced into microcosms with sterile brackish water (salinity variable from 21 to 22 gl -1) taken from Lake Shira (Khakasia, Russia). The survival of the microorganism was estimated both by measuring the growth of the colonies on solid nutrient media and by the bioluminescence exhibited by the transgenic strain in samples from the microcosms and in the enrichment culture with the added selective factor - ampicillin (50 ?g/ml). In the enrichment culture, the bioluminescent signal was registered through the 160-day experiment. It has been shown that in the closed microcosms with brackish water the E. coli strain becomes heterogeneous in its ampicillin resistance. The populations of the transgenic strain were mainly represented by isolates able to persist in the medium containing 50 ?g/ml, but there were also the cells (about 10%) with the threshold of ampicillin resistance not more than 0.05 ?g/ml. Thus, it was shown that in the microcosms with brackish water and in the absence of the selective factor the transgenic strain survives and retails the recombinant plasmid.

Boyandin, A. N.; Lobova, T. I.; Popova, L. Yu.; Pechurkin, N. S.

433

Survival and alteration of the plasmid-containing microorganism Escherichia coli Z905/pPHL7 introduced into manmade closed aquatic microcosms  

NASA Astrophysics Data System (ADS)

It has been found out whether the transgenic microorganism Escherichia coli Z905/pPHL7 (Aprlux+) can exist for a long time at an elevated concentration of mineral salts. The microorganism was introduced into microcosms with the sterile brackish water taken from Lake Shira. The survival of the microorganism was estimated both by measuring the growth of the colonies on solid nutrient media and by the bioluminescence exhibited by the transgenic strain in the samples of the microcosms and in the enrichment culture with the added selective factor - ampicillin (50 ?g/ml). In the enrichment culture the bioluminescent signal was registered through the 160-day experiment. It has been shown that in the closed microcosms with the brackish water the E. coli strain becomes heterogeneous in its ampicillin resistance. The populations of the transgenic strain were mainly represented by the isolates able to persist in the medium with 50 ?g/ml, but there were also the cells (about 1%) with the threshold of ampicillin resistance not more than 0.05 ?g/ml. Thus, it has been recorded that in the microcosms with the brackish water and in the absence of the selective factor the transgenic strain survives and retains the recombinant plasmid.

Boyandin, A.; Lobova, T.; Popova, L.; Pechurkin, N.

434

Structure of the Cyclomodulin Cif from Pathogenic Escherichia coli  

SciTech Connect

Bacterial pathogens have evolved a sophisticated arsenal of virulence factors to modulate host cell biology. Enteropathogenic and enterohemorrhagic Escherichia coli (EPEC and EHEC) use a type III protein secretion system (T3SS) to inject microbial proteins into host cells. The T3SS effector cycle inhibiting factor (Cif) produced by EPEC and EHEC is able to block host eukaryotic cell-cycle progression. We present here a crystal structure of Cif, revealing it to be a divergent member of the superfamily of enzymes including cysteine proteases and acetyltransferases that share a common catalytic triad. Mutation of these conserved active site residues abolishes the ability of Cif to block cell-cycle progression. Finally, we demonstrate that irreversible cysteine protease inhibitors do not abolish the Cif cytopathic effect, suggesting that another enzymatic activity may underlie the biological activity of this virulence factor.

Hsu, Y.; Jubelin, G; Taieb, F; Nougayrède, J; Oswald, E; Stebbins, C

2008-01-01

435

Novel Antigens for enterotoxigenic Escherichia coli (ETEC) Vaccines  

PubMed Central

Enterotoxigenic Escherichia coli (ETEC) are the most common bacterial pathogens-causing diarrhea in developing countries where they cause hundreds of thousands of deaths, mostly in children. These organisms are leading cause of diarrheal illness in travelers to endemic countries. ETEC pathogenesis, and consequently vaccine approaches, have largely focused on plasmid-encoded enterotoxins or fimbrial colonization factors. To date these approaches have not yielded a broadly protective vaccine. However, recent studies suggest that ETEC pathogenesis is more complex than previously appreciated and involves additional plasmid and chromosomally-encoded virulence molecules that can be targeted in vaccines. Here, we review recent novel antigen discovery efforts, potential contribution of these proteins to the molecular pathogenesis of ETEC and protective immunity, and the potential implications for development of next generation vaccines for important pathogens. These proteins may help to improve the effectiveness of future vaccines by making simpler and possibly broadly protective because of their conserved nature. PMID:24702311

Fleckenstein, James M.; Sheikh, Alaullah; Qadri, Firdausi

2014-01-01

436

Photoreactivation in phr mutants of Escherichia coli K-12  

SciTech Connect

We have investigated the genetics of photoreactivation in Escherichia coli K-12. We found that strains with point mutations or deletions in the phr gene showed a significant residual level of photoreactivation after exposure to large fluences of photoreactivating light. It had been previously proposed that a gene in the gal-att lambda interval is also involved in photoreactivation and that the residual photoreactivating activity might be due to this so-called phrA gene located at this interval. We found that deletions of the gal-att lambda region had no effect on either the rate or the final extent of photoreactivation observed in phr+ cells or phr mutants; however strains carrying the delta (gal-att lambda) deletions displayed increased sensitivity to near-UV radiation.

Husain, I.; Sancar, A.

1987-06-01

437

Chemiluminescence induced by phagocytosis of Escherichia coli by polymorphonuclear leucocytes.  

PubMed

Chemiluminescence emitted by phagocytosing human polymorphonuclear leucocytes stimulated by Escherichia coli was measured using a liquid scintillation counter equipped with a multichannel analyser. In the presence of the amplifying agent luminol, light emission can be divided into two channels, one of which ('high energy') appears to correlate directly with phagocytic activity of the PMNL, and the other ('low energy') with the background luminol dioxygenation by the cells. Measuring in the 'high energy' window also eliminates the normal 'out of coincidence' background. The method is applicable to measuring opsonizing capacity of different sera, and responds to PMNL number, age, composition of assay medium and the integrity of the stimulating bacteria. Other bacterial strains produce a similar response, as does the artificial stimulator zymosan. Low temperature and anaerobiosis, which inhibit phagocytic killing, also suppress light emission. PMID:6389762

Fazeli, A; Richards, L

1984-09-01

438

Collective THz dynamics in living Escherichia coli cells  

NASA Astrophysics Data System (ADS)

We have employed neutron Brillouin spectroscopy to study coherent collective density fluctuations in the biological macromolecular components of living Escherichia coli cells. To highlight the contribution of the macromolecular material alone, a suitably prepared mixture of light and heavy water was exploited to cancel the scattering length of intracellular water. The present results indicate that the cellular biomaterial sustains THz coherent density fluctuations, characterised by a propagating mode travelling at about 3600 m/s and by a localised mode at energies between 4 and 7 meV. A comparison with both hydration water and simpler biomolecules, such as proteins or DNA, brings further support to the idea that the dynamical coupling between biomolecular structures and biological water provides the delicate dynamical adaptation needed to achieve a full biological functionality. Finally, the behaviour of the damping factors of the observed collective modes strengthens the dynamical similarity of biological systems with glass-forming materials.

Sebastiani, F.; Orecchini, A.; Paciaroni, A.; Jasnin, M.; Zaccai, G.; Moulin, M.; Haertlein, M.; De Francesco, A.; Petrillo, C.; Sacchetti, F.

2013-10-01

439

Escherichia coli activity characterization using a laser dynamic speckle technique  

E-print Network

The results of applying a laser dynamic speckle technique to characterize bacterial activity are presented. The speckle activity was detected in two-compartment Petri dishes. One compartment was inoculated and the other one was left as a control blank. The speckled images were processed by the recently reported temporal difference method. Three inoculums of 0.3, 0.5, and 0.7 McFarland units of cell concentration were tested; each inoculum was tested twice for a total of six experiments. The dependences on time of the mean activity, the standard deviation of activity and other descriptors of the speckle pattern evolution were calculated for both the inoculated compartment and the blank. In conclusion the proposed dynamic speckle technique allows characterizing the activity of Escherichia coli bacteria in solid medium.

Ramírez-Miquet, Evelio E; Contreras-Alarcón, Orestes R

2012-01-01

440

Local immune response to Escherichia coli pili in experimental pyelonephritis.  

PubMed Central

The local immune response to pili of Escherichia coli O6:K13:H1 was determined in experimental hematogenous pyelonephritis in rabbits. Pili purified from sheared cells by ammonium sulfate precipitation were found to be pure by electron microscopy and negative for lipopolysaccharide by limulus lysate assay. Antipilus antibody was detected in serum and newly synthesized protein from infected animals with enzyme-linked immunosorbent assay. Serum and local (intrarenal) antibodies were of the immunoglobulin G class, were detectable by day 20 of infection, and persisted though 250 days of infection. These data suggest that pili are present on the organism at the site of infection, since they induce the local synthesis of antipilus antibody in experimental pyelonephritis. PMID:6111536

Smith, J W; Wagner, S; Swenson, R M

1981-01-01

441

Triosephosphates are toxic to superoxide dismutase-deficient Escherichia coli.  

PubMed

Increase in the production of triosephosphates has been considered an important factor leading to diabetic complications. It might be expected that like the other short chain monosaccharides, triosephosphates autoxidize producing superoxide radical and alpha,beta-diketones. Since superoxide can also initiate the oxidation of short chain sugars, free radical chain reactions are possible. If such reactions occur in vivo, triosephosphates would be more deleterious to cells lacking superoxide dismutase (SOD) than to normal cells. Here we demonstrate that triosephosphates kill a SOD-deficient Escherichia coli mutant much more than the parental, SOD-proficient strain. The effect is oxygen-dependent and is partially suppressed by aminoguanidine. Increased production of superoxide and diketones appeared to be the cause of triosephosphates toxicity. PMID:12880950

Benov, Ludmil; Beema, Anees F; Sequeira, Fatima

2003-07-23

442

Failed escape: solid surfaces prevent tumbling of Escherichia coli.  

PubMed

Understanding how bacteria move close to surfaces is crucial for a broad range of microbial processes including biofilm formation, bacterial dispersion, and pathogenic infections. We used digital holographic microscopy to capture a large number (>10(3)) of three-dimensional Escherichia coli trajectories near and far from a surface. We found that within 20???m from a surface tumbles are suppressed by 50% and reorientations are largely confined to surface-parallel directions, preventing escape of bacteria from the near-surface region. A hydrodynamic model indicates that the tumble suppression is likely due to a surface-induced reduction in the hydrodynamic force responsible for the flagellar unbundling that causes tumbling. These findings imply that tumbling does not provide an effective means to escape trapping near surfaces. PMID:25148353

Molaei, Mehdi; Barry, Michael; Stocker, Roman; Sheng, Jian

2014-08-01

443

Effects of the Rare Earth Cerium on Escherichia coli  

PubMed Central

The rare earth cerium was found to bind rapidly to Escherichia coli. Cerium inhibited oxygen uptake in the presence of glucose as well as the endogenous respiration of glucose-grown cells. For a cell concentration of 4 mg per ml, maximal inhibition was obtained at 120 ?g per ml. Greater concentrations did not increase the inhibitory effect. Cerium inhibited 14CO2 evolution and 14C uptake from uniformly labeled glucose. Marked changes in the distribution of 14C incorporated into different chemical fractions of the cell were noted. The most striking changes occurred in the alcohol- and alcohol ether-soluble fractions, in which the 14C activity was increased 5- to 20-fold in the presence of cerium. PMID:4866102

Sobek, Joseph M.; Talburt, Dwight E.

1968-01-01

444

Enterotoxigenic Escherichia coli infection induces intestinal epithelial cell autophagy.  

PubMed

The morbidity and mortality in piglets caused by enterotoxigenic Escherichia coli (ETEC) results in large economic losses to the swine industry, but the precise pathogenesis of ETEC-associated diseases remains unknown. Intestinal epithelial cell autophagy serves as a host defense against pathogens. We found that ETEC induced autophagy, as measured by both the increased punctae distribution of GFP-LC3 and the enhanced conversion of LC3-I to LC3-II. Inhibiting autophagy resulted in decreased survival of IPEC-1 cells infected with ETEC. ETEC triggered autophagy in IPEC-1 cells through a pathway involving the mammalian target of rapamycin (mTOR), the extracellular signal-regulated kinases 1/2 (ERK1/2), and the AMP-activated protein kinase (AMPK). PMID:24742948

Tang, Yulong; Li, Fengna; Tan, Bie; Liu, Gang; Kong, Xiangfeng; Hardwidge, Philip R; Yin, Yulong

2014-06-25

445

Profiling of the reactive oxygen species-related ecotoxicity of CuO, ZnO, TiO 2 , silver and fullerene nanoparticles using a set of recombinant luminescent Escherichia coli strains: differentiating the impact of particles and solubilised metals  

Microsoft Academic Search

We propose a novel combination of high-throughput luminescent bacterial tests for the evaluation of the reactive oxygen species\\u000a (ROS)-generating potential of engineered nanoparticles (eNPs) and the role of solubilised metal ions in this process. The\\u000a set of tests consists of differently engineered recombinant Escherichia coli strains: (1) a new sensor strain, which bioluminescence is induced by superoxide anions; (2) six

A. Ivask; O. Bondarenko; N. Jepihhina; A. Kahru

2010-01-01

446

An Unusual Case of Early Onset Persistent Escherichia coli Septicemia Associated with Endocarditis  

PubMed Central

Escherichia coli infection is very common cause of early onset septicemia especially in very low-birth-weight newborns, but E. coli endocarditis has not been described in newborns. E. coli endocarditis, even in the adult population, is a rare and not well-characterized disease and is associated with high mortality. We report a very unusual presentation of persistent E. coli infection associated with endocarditis. PMID:24147246

Gupta, Sachin K.; Nanda, Vishakha; Malviya, Prashant; Jacobs, Norman; Naheed, Z.; Joseph, Tessy

2013-01-01

447

Effect of Phosphorus on Survival of Escherichia coli in Drinking Water Biofilms?  

PubMed Central

The effect of phosphorus addition on survival of Escherichia coli in an experimental drinking water distribution system was investigated. Higher phosphorus concentrations prolonged the survival of culturable E. coli in water and biofilms. Although phosphorus addition did not affect viable but not culturable (VBNC) E. coli in biofilms, these structures could act as a reservoir of VBNC forms of E. coli in drinking water distribution systems. PMID:17416695

Juhna, Talis; Birzniece, Dagne; Rubulis, Janis

2007-01-01

448

Forage Feeding to Reduce Preharvest Escherichia coli Populations in Cattle, a Review  

Microsoft Academic Search

Although Escherichia coli are commensal organisms thatresidewithinthehost gut,somepathogenicstrains of E. coli can cause hemorrhagic colitis in humans. The most notable enterohemorrhagic E. coli (EHEC) strain isO157:H7.Cattleareasymptomaticnaturalreservoirs of E. coli O157:H7, and it has been reported that as many as 30% of all cattle are carriers of this pathogen, and in some circumstances this can be as high as 80%. Feedlot

T. R. Callaway; R. O. Elder; J. E. Keen; R. C. Anderson; D. J. Nisbet

2003-01-01

449

Effect of Cattle Diet on Escherichia coli O157:H7 Acid Resistance  

PubMed Central

The duration of shedding of Escherichia coli O157 isolates by hay-fed and grain-fed steers experimentally inoculated with E. coli O157:H7 was compared, as well as the acid resistance of the bacteria. The hay-fed animals shed E. coli O157 longer than the grain-fed animals, and irrespective of diet, these bacteria were equally acid resistant. Feeding cattle hay may increase human infections with E. coli O157:H7. PMID:10388727

Hovde, Carolyn J.; Austin, Paula R.; Cloud, Karen A.; Williams, Christopher J.; Hunt, Carl W.

1999-01-01

450

Short Communication: Survival of Escherichia coli O157:H7 in Dairy Cattle Drinking Water  

Microsoft Academic Search

Cattle drinking water from two dairy farms was used in a study to determine the survival characteris- tics of the bacterial pathogen Escherichia coli O157:H7 and wild-type E. coli. The E. coli O157:H7 inoculum consisted of a consortium of isolates obtained from dairy cattle. Fresh manure was used as the source for the wild-type E. coli. In the water source

E. W. Rice; C. H. Johnson

2000-01-01

451

Broiler chickens as source of human fluoroquinolone-resistant Escherichia coli, Iceland.  

PubMed

To investigate feed as a source for fluoroquinolone-resistant Escherichia coli in broiler chickens, we compared antimicrobial drug-resistant E. coli from broiler feed and broilers with ciprofloxacin-resistant human clinical isolates by using pulsed-field gel electrophoresis. Feed was implicated as a source for ciprofloxacin-resistant broiler-derived E. coli and broilers as a source for ciprofloxacin-resistant human-derived E. coli. PMID:20031060

Thorsteinsdottir, Thorunn R; Haraldsson, Gunnsteinn; Fridriksdottir, Vala; Kristinsson, Karl G; Gunnarsson, Eggert

2010-01-01

452

Broiler Chickens as Source of Human Fluoroquinolone-Resistant Escherichia coli, Iceland  

PubMed Central

To investigate feed as a source for fluoroquinolone-resistant Escherichia coli in broiler chickens, we compared antimicrobial drug–resistant E. coli from broiler feed and broilers with ciprofloxacin-resistant human clinical isolates by using pulsed-field gel electrophoresis. Feed was implicated as a source for ciprofloxacin-resistant broiler-derived E. coli and broilers as a source for ciprofloxacin-resistant human-derived E. coli. PMID:20031060

Haraldsson, Gunnsteinn; Fridriksdottir, Vala; Kristinsson, Karl G.; Gunnarsson, Eggert

2010-01-01

453

A surface accumulator of Escherichia coli in water flow.  

PubMed

The objective of this research is to design and optimise a mini/micro-channel based surface accumulator of Escherichia coli to be detected by acoustic wave biosensors. A computational research has been carried out using the state of the art software, CFD-ACE with water as bacteria bearing fluid. E. coli bacteria have been modelled as random discrete particles tracked by solving the Lagrangian equations. The design challenges are to achieve low shear force (pico-N), high concentration at accumulation and high enough Reynolds number to avoid bacteria swimming. A range of low Reynolds number (Re) from 28.2 to 58.3 has been considered along with the effects of particle-boundary interactions, gravity, Saffman lift and Magnus lift. About four orders of magnitude higher concentration at accumulation than the inlet concentration and lower shear force in the order of less than pico-N have been achieved in the optimised design with particles accumulating at a specific location under random particle-boundary interactions. PMID:18663613

Mayeed, M S; Al-Mekhnaqi, A M; Auner, G W; Newaz, G M

2009-02-01

454

Vaccinia DNA topoisomerase I promotes illegitimate recombination in Escherichia coli.  

PubMed Central

Vaccinia virus encapsidates a Mr 32,000 type IDNA topoisomerase. Although the vaccinia gene encoding the topoisomerase is essential for virus growth, the role of the enzyme in vivo remains unclear. In the present study, the physiologic consequences of vaccinia topoisomerase action have been examined in a heterologous system, Escherichia coli. The vaccinia topoisomerase gene was inducibly expressed in an int-lambda lysogen BL21(DE3) using a T7 RNA polymerase-based transcription system. Expression of active topoisomerase in this context resulted in recA-dependent lysogenic induction as well as cell lysis. Surprisingly, topoisomerase expression also effected a 200-fold increase in the titer of infectious lambda phage, apparently by promoting int-independent prophage excision. This effect was not observed during lysogenic induction with nalidixic acid. Restriction analysis of genomic DNA from plaque-purified excisants revealed (in 10 of 10 cases) gross alterations of the DNA structure around the att site relative to the structure of the parental phage DE3. It is construed therefore that vaccinia DNA topoisomerase I acts to promote illegitimate recombination in E. coli. Images PMID:2542933

Shuman, S

1989-01-01

455

Bacteriophages with the Ability to Degrade Uropathogenic Escherichia Coli Biofilms  

PubMed Central

Escherichia coli-associated urinary tract infections (UTIs) are among the most common bacterial infections in humans. UTIs are usually managed with antibiotic therapy, but over the years, antibiotic-resistant strains of uropathogenic E. coli (UPEC) have emerged. The formation of biofilms further complicates the treatment of these infections by making them resistant to killing by the host immune system as well as by antibiotics. This has encouraged research into therapy using bacteriophages (phages) as a supplement or substitute for antibiotics. In this study we characterized 253 UPEC in terms of their biofilm-forming capabilities, serotype, and antimicrobial resistance. Three phages were then isolated (vB_EcoP_ACG-C91, vB_EcoM_ACG-C40 and vB_EcoS_ACG-M12) which were able to lyse 80.5% of a subset (42) of the UPEC strains able to form biofilms. Correlation was established between phage sensitivity and specific serotypes of the UPEC strains. The phages’ genome sequences were determined and resulted in classification of vB_EcoP_ACG-C91 as a SP6likevirus, vB_EcoM_ACG-C40 as a T4likevirus and vB_EcoS_ACG-M12 as T1likevirus. We assessed the ability of the three phages to eradicate the established biofilm of one of the UPEC strains used in the study. All phages significantly reduced the biofilm within 2–12 h of incubation. PMID:22590682

Chibeu, Andrew; Lingohr, Erika J.; Masson, Luke; Manges, Amee; Harel, Josee; Ackermann, Hans-W.; Kropinski, Andrew M.; Boerlin, Patrick

2012-01-01

456

Effect of Pili on Susceptibility of Escherichia coli to Phagocytosis  

PubMed Central

The degree of piliation of 20 clinical isolates of Escherichia coli was correlated with their susceptibility to phagocytosis by human polymorphonuclear leukocytes. Piliation was quantitated by negative staining, and phagocytosis was quantitated by a monolayer technique. Ingestion was confirmed by electron microscopy. In the absence of source of opsonins, there was a positive correlation between the degree of piliation and susceptibility to phagocytosis (y = 0.83x + 19.58; correlation coefficient = 0.65; P < 0.01). Heavily piliated strains were no longer phagocytized after their pili were removed by ultraviolet irradiation. Phagocytosis was reduced 75% in the presence of 0.1 M d-mannose, an agent which competitively inhibits binding of pili to cell surfaces. l-Mannose, d-glucose, and d-galactose were much less inhibitory. The viability of piliated organisms was reduced by 1 log after 1 h of incubation with polymorphonuclear leukocytes. Addition of 10% fresh human serum increased both the rate and completeness of killing. These observations suggest that polymorphonuclear leukocytes may interact with the pili of E. coli to promote phagocytosis. This phenomenon may have clinical relevance in situations where normal opsonic activity is poor, such as the renal medulla. Images PMID:378843

Silverblatt, Fredric J.; Dreyer, Jerrold S.; Schauer, Susan

1979-01-01

457

Improvements In Ethanologenic Escherichia Coli and Klebsiella Oxytoca  

SciTech Connect

The current Verenium cellulosic ethanol process is based on the dilute-acid pretreatment of a biomass feedstock, followed by a two-stage fermentation of the pentose sugar-containing hydrolysate by a genetically modified ethanologenic Escherichia coli strain and a separate simultaneous saccharification-fermentation (SSF) of the cellulosic fraction by a genetically modified ethanologenic Klebsiella oxytoca strain and a fungal enzyme cocktail. In order to reduce unit operations and produce a fermentation beer with higher ethanol concentrations to reduce distillation costs, we have proposed to develop a simultaneous saccharification co-fermentation (SScF) process, where the fermentation of the pentose-containing hydrolysate and cellulosic fraction occurs within the same fermentation vessel. In order to accomplish this goal, improvements in the ethanologens must be made to address a number of issues that arise, including improved hydrolysate tolerance, co-fermentation of the pentose and hexose sugars and increased ethanol tolerance. Using a variety of approaches, including transcriptomics, strain adaptation, metagenomics and directed evolution, this work describes the efforts of a team of scientists from Verenium, University of Florida, Massachusetts Institute of Technology and Genomatica to improve the E. coli and K. oxytoca ethanologens to meet these requirements.

Dr. David Nunn

2010-09-30

458

Characterization of Two New Aminopeptidases in Escherichia coli  

PubMed Central

Two genes in the Escherichia coli genome, ypdE and ypdF, have been cloned and expressed, and their products have been purified. YpdF is shown to be a metalloenzyme with Xaa-Pro aminopeptidase activity and limited methionine aminopeptidase activity. Genes homologous to ypdF are widely distributed in bacterial species. The unique feature in the sequences of the products of these genes is a conserved C-terminal domain and a variable N-terminal domain. Full or partial deletion of the N terminus in YpdF leads to the loss of enzymatic activity. The conserved C-terminal domain is homologous to that of the methionyl aminopeptidase (encoded by map) in E. coli. However, YpdF and Map differ in their preference for the amino acid next to the initial methionine in the peptide substrates. The implication of this difference is discussed. ypdE is the immediate downstream gene of ypdF, and its start codon overlaps with the stop codon of ypdF by 1 base. YpdE is shown to be a metalloaminopeptidase and has a broad exoaminopeptidase activity. PMID:15901689

Zheng, Yu; Roberts, Richard J.; Kasif, Simon; Guan, Chudi

2005-01-01

459

Epidemiology of Escherichia coli Serotype O157:H7  

E-print Network

Escherichia coli O157:H7 is a recently recognized pathogen that causes a dysentery-like illness. The disease is typically a bloody diarrhea, often without prominent fever, that can be complicated by hemolytic uremic syndrome. It is primarily found in developed countries. Only one confirmed outbreak has occurred in a developing country–in Swaziland in 1992 affecting 20,000 persons. Other outbreaks have been thought to occur but have not been confirmed. The major modes of transmission are through undercooked beef, unpasteurized milk, and foods that have come in contact with materials of animal origin. Waterborne outbreaks have been reported, as have outbreaks associated with swimming in contaminated lakes. The organism produces toxins similar to those produced by Shigella dysenteriae serotype 1. Treatment with antimicrobial agents has not been demonstrated to be useful in improving the course or outcome of infection with E. coli O157:H7. In fact, treating with some agents may actually worsen the outcome. Since no treatment is recommended, it is not necessary to test the antimicrobial susceptibility

unknown authors

460

Porin activity in the osmotic shock fluid of Escherichia coli.  

PubMed Central

Osmotic shock fluid of Escherichia coli exhibited pore-forming activity. This activity could be followed by an in vitro assay based on the conductivity increase for ions due to the presence of pores in black lipid membranes. The histogram (the distribution of conductivity increments in a single pore experiment) obtained with osmotic shock fluid from E. coli was identical to the histogram obtained by detergent-solubilized porin isolated from the outer membrane. The osmotic shock fluid from porin-negative mutants also exhibited pore activity, although the histogram and ion specificity were different from those of porin. Antibodies raised against detergent-solubilized porin were able to form precipitin lines by the Ouchterlony immunodiffusion technique when shock fluids, but not detergent-solubilized porin, were used. These antibodies prevented the formation of pores when shock fluids contained porin but not when shock fluids obtained from porin-negative mutants were used. Macroscopic membrane conductivity of shock fluids due to porin exhibited a concentration dependence, in contrast to detergent-solubilized porin. These results indicate that the hydrodynamic properties of periplasmic or "soluble" porin are different from those of the detergent-solubilized porin of the outer membrane. Periplasmic porin comprises about 0.7% of total protein in the osmotic shock fluid. Images PMID:357415

Benz, R; Boehler-Kohler, B A; Dieterle, R; Boos, W

1978-01-01

461

Structure of CFA/I fimbriae from enterotoxigenic Escherichia coli  

SciTech Connect

Adhesion pili (fimbriae) play a critical role in initiating the events that lead to intestinal colonization and diarrheal disease by enterotoxigenic Escherichia coli (ETEC), an E. coli pathotype that inflicts an enormous global disease burden. We elucidate atomic structures of an ETEC major pilin subunit, CfaB, from colonization factor antigen I (CFA/I) fimbriae. These data are used to construct models for 2 morphological forms of CFA/I fimbriae that are both observed in vivo: the helical filament into which it is typically assembled, and an extended, unwound conformation. Modeling and corroborative mutational data indicate that proline isomerization is involved in the conversion between these helical and extended forms. Our findings affirm the strong structural similarities seen between class 5 fimbriae (from bacteria primarily causing gastrointestinal disease) and class 1 pili (from bacteria that cause urinary, respiratory, and other infections) in the absence of significant primary sequence similarity. They also suggest that morphological and biochemical differences between fimbrial types, regardless of class, provide structural specialization that facilitates survival of each bacterial pathotype in its preferred host microenvironment. Last, we present structural evidence for bacterial use of antigenic variation to evade host immune responses, in that residues occupying the predicted surface-exposed face of CfaB and related class 5 pilins show much higher genetic sequence variability than the remainder of the pilin protein.

Li, Yong-Fu; Poole, Steven; Nishio, Kazuya; Jang, Ken; Rasulova, Fatima; McVeigh, Annette; Savarino, Stephen J.; Xia, Di; Bullitt, Esther; (BU-M); (NIH); (NMRC)

2009-10-21

462

Nutrient dependence of RNase E essentiality in Escherichia coli.  

PubMed

Escherichia coli cells normally require RNase E activity to form colonies (colony-forming ability [CFA]). The CFA-defective phenotype of cells lacking RNase E is partly reversed by overexpression of the related endoribonuclease RNase G or by mutation of the gene encoding the RNA helicase DeaD. We found that the carbon source utilization by rne deaD doubly mutant bacteria differs from that of rne(+) cells and from that of cells mutated in deaD alone and that the loss of rne function in these bacteria limits conversion of the glycolytic pathway product phosphoenolpyruvate to the tricarboxylic acid (TCA) cycle intermediate oxaloacetic acid. We show that the mechanism underlying this effect is reduced production of the enzyme phosphoenolpyruvate carboxylase (PPC) and that adventitious overexpression of PPC, which facilitates phosphoenolpyruvate utilization and connects the glycolytic pathway with the TCA cycle, restored CFA to rne deaD mutant bacteria cultured on carbon sources that otherwise were unable to sustain growth. We further show that bacteria producing full-length RNase E, which allows formation of degradosomes, have nutritional requirements different from those of cells supplied with only the N-terminal catalytic region of RNase E and that mitigation of RNase E deficiency by overexpression of a related RNase, RNase G, is also affected by carbon source. Our results reveal previously unsuspected effects of RNase E deficiency and degradosome formation on nutrient utilization by E. coli cells. PMID:23275245

Tamura, Masaru; Moore, Christopher J; Cohen, Stanley N

2013-03-01

463

Molecular response of Escherichia coli adhering onto nanoscale topography  

PubMed Central

Bacterial adhesion onto abiotic surfaces is an important issue in biology and medicine since understanding the bases of such interaction represents a crucial aspect in the design of safe implant devices with intrinsic antibacterial characteristics. In this framework, we investigated the effects of nanostructured metal substrates on Escherichia coli adhesion and adaptation in order to understand the bio-molecular dynamics ruling the interactions at the interface. In particular, we show how highly controlled nanostructured gold substrates impact the bacterial behavior in terms of morphological changes and lead to modifications in the expression profile of several genes, which are crucially involved in the stress response and fimbrial synthesis. These results mainly demonstrate that E. coli cells are able to sense even slight changes in surface nanotopography and to actively respond by activating stress-related pathways. At the same time, our findings highlight the possibility of designing nanoengineered substrates able to trigger specific bio-molecular effects, thus opening the perspective of smartly tuning bacterial behavior by biomaterial design. PMID:23078758

2012-01-01

464

Molecular response of Escherichia coli adhering onto nanoscale topography.  

PubMed

Bacterial adhesion onto abiotic surfaces is an important issue in biology and medicine since understanding the bases of such interaction represents a crucial aspect in the design of safe implant devices with intrinsic antibacterial characteristics. In this framework, we investigated the effects of nanostructured metal substrates on Escherichia coli adhesion and adaptation in order to understand the bio-molecular dynamics ruling the interactions at the interface. In particular, we show how highly controlled nanostructured gold substrates impact the bacterial behavior in terms of morphological changes and lead to modifications in the expression profile of several genes, which are crucially involved in the stress response and fimbrial synthesis. These results mainly demonstrate that E. coli cells are able to sense even slight changes in surface nanotopography and to actively respond by activating stress-related pathways. At the same time, our findings highlight the possibility of designing nanoengineered substrates able to trigger specific bio-molecular effects, thus opening the perspective of smartly tuning bacterial behavior by biomaterial design. PMID:23078758

Rizzello, Loris; Galeone, Antonio; Vecchio, Giuseppe; Brunetti, Virgilio; Sabella, Stefania; Pompa, Pier Paolo

2012-01-01

465

Pattern Formation of Bacterial Colonies by Escherichia coli  

NASA Astrophysics Data System (ADS)

We have studied the morphological diversity and change in bacterial colonies, using the bacterial species Escherichia coli, as a function of both agar concentration Ca and nutrient concentration Cn. We observed various colony patterns, classified them into four types by pattern characteristics and established a morphological diagram by dividing it into four regions. They are regions A [diffusion-limited aggregation (DLA)-like], B (Eden-like), C (concentric-ring), and D (fluid-spreading). In particular, we have observed a concentric-ring colony growth for E. coli. We focused on the periodic growth in region C and obtained the following results: (i) A colony grows cyclically with the growing front repeating an advance (migration phase) and a momentary rest (consolidation phase) alternately. (ii) The growth width L and the bulge width W in one cycle decrease asymptotically to certain values, when Ca is increased. (iii) L does not depend on Cn, while W is an increasing function of Cn. Plausible mechanisms are proposed to explain the experimental results, by comparing them with those obtained for other bacterial species such as Proteus mirabilis and Bacillus subtilis.

Tokita, Rie; Katoh, Takaki; Maeda, Yusuke; Wakita, Jun-ichi; Sano, Masaki; Matsuyama, Tohey; Matsushita, Mitsugu

2009-07-01

466

Escherichia coli ribonucleotide reductase expression is cell cycle regulated.  

PubMed Central

The expression of the genes encoding ribonucleotide reductase in Escherichia coli was investigated in cultures synchronized by obtaining the smallest cells in a population after sucrose gradient centrifugation. Specific activity of ribonucleotide reductase and DNA initiation were found to increase in parallel, periodically as a function of the cell cycle. The expression of nrd was also determined in cells synchronized by periodic repeated doubling in a phosphate limited medium. Antibodies directed against the B2 subunit of ribonucleotide reductase were raised in a rabbit and purified. Immunoprecipitation of the B2 subunit and RNA-DNA dot blot hybridization assays were developed and employed to determine the expression of ribonucleotide reductase translational and transcriptional products during the cell cycle. Both of nrd-mRNA and B2 subunit expression were found to increase each generation at approximately the same time DNA synthesis was initiated and then to decrease back to the basal level shortly after DNA initiation. These results provided evidence of cell cycle dependent regulation of ribonucleotide reductase in E. coli. When the upstream regulatory region of nrd was fused to a promoterless lacZ gene on a single copy plasmid, lac-mRNA and beta-galactosidase were found to be synthesized in parallel to nrd expression from the chromosomal operon. When nrd sequences surrounding the promoter were removed from this construct, lac-mRNA and beta-galactosidase synthesis were no longer cell cycle regulated. Images PMID:1384814

Sun, L; Fuchs, J A

1992-01-01

467

Escherichia coli 0157 enterohaemorrhagic colitis associated with pyelonephritis: CT findings.  

PubMed

Escherichia coli 0157:H7 is increasingly being recognized as a cause of infectious colitis, which typically results in bloody diarrhoea in an afebrile patient. The absence of fever often means that an infectious process is not considered in the differential diagnosis, particularly as this organism will not be detected in routine stool cultures. Inappropriate antibiotic therapy may increase the risk of development of haemolytic uraemic syndrome, a potentially fatal complication of this form of colitis, hence the importance of accurate diagnosis. On CT, it is characterized by severe diffuse colonic wall thickening, with little or no pericolic inflammatory changes. The radiologist may be the first to suspect the correct diagnosis and so should be aware of its imaging appearances. We report the case of a 19-year-old man who presented with typical radiological findings of enterohaemorrhagic colitis and whose CT also showed evidence of acute pyelonephritis; we suggest that this combination of abnormalities should further heighten radiologists' suspicions of infection due to E. coli 0157:H7, despite the absence of fever. PMID:19325040

Heffernan, E; Chatur, N; Zwirewich, C

2009-04-01

468

Effect of cobalt on Escherichia coli metabolism and metalloporphyrin formation  

PubMed Central

Toxicity in Escherichia coli resulting from high concentrations of cobalt has been explained by competition of cobalt with iron in various metabolic processes including Fe–S cluster assembly, sulfur assimilation, production of free radicals and reduction of free thiol pool. Here we present another aspect of increased cobalt concentrations in the culture medium resulting in the production of cobalt protoporphyrin IX (CoPPIX), which was incorporated into heme proteins including membrane-bound cytochromes and an expressed human cystathionine beta-synthase (CBS). The presence of CoPPIX in cytochromes inhibited their electron transport capacity and resulted in a substantially decreased respiration. Bacterial cells adapted to the increased cobalt concentration by inducing a modified mixed acid fermentative pathway under aerobiosis. We capitalized on the ability of E. coli to insert cobalt into PPIX to carry out an expression of CoPPIX-substituted heme proteins. The level of CoPPIX-substitution increased with the number of passages of cells in a cobalt-containing medium. This approach is an inexpensive method to prepare cobalt-substituted heme proteins compared to in vitro enzyme reconstitution or in vivo replacement using metalloporphyrin heme analogs and seems to be especially suitable for complex heme proteins with an additional coenzyme, such as human CBS. PMID:21184140

Majtan, Tomas; Frerman, Frank E.

2011-01-01

469

Production of acetol from glycerol using engineered Escherichia coli.  

PubMed

Escherichia coli Lin43 is a strain which has some mutations in glycerol kinase (GlpK) and the repressor for the glycerol 3-phosphate regulon (GlpR). When exposed to glycerol, it quickly accumulates lethal levels of methylglyoxal, which is a precursor of acetol; acetol is important for the manufacture of polyols, acrolein, dyes, and skin tanning agents. This work reports the engineering of E. coli Lin 43 for the conversion of glycerol into acetol. First, the glyoxalase system was interrupted by deleting the gloA gene, which increased the acetol yield by 32%. In addition, the aldehyde reductase YqhD was overexpressed which led to an increase of acetol production by 11.4-fold. Acetol production was optimized by varying the cell density, glycerol concentration, supplemental carbon source, pH and temperature. Under the optimal conditions (OD600=20, 20 g/L glycerol, 2g/L succinate, pH 7.0, and 28°C), we obtained 5.4 g/L acetol in 21 h. PMID:24113547

Zhu, Hongliang; Yi, Xianyang; Liu, Yi; Hu, Hongbo; Wood, Thomas K; Zhang, Xuehong

2013-12-01

470

Microwave inactivation of Escherichia coli in healthcare waste.  

PubMed

Public healthcare wastes from the city of Ribeirão Preto, SP, Brazil, pre-sterilised in an autoclave, were inoculated with 5 x 10(5) microorganisms of the species Escherichia coli in vegetative form for microwave processing on a laboratory scale. An analysis was made of the influence of radiation exposure time (15, 25, 30 and 40 min) and power per waste mass unit (60, 80 and 100 W/kg) on the percentage of inactivation of the microorganisms at an incoming waste moisture level of 50%. The experimental results were adjusted based on Chick's law. The activation energies and the Arrhenius pre-exponential factors were determined by the least squares method. The kinetic parameters obtained allow one to predict the degree of inactivation achieved with E. coli in typical healthcare waste, based on the radiation exposure time and temperature. For example, the waste disinfection time required for the inactivation level equivalent to 4Log 10 was estimated to range from 48 to 53 min for wastes processed at 100 W/kg and at temperatures of 90-105 degrees C, respectively. Thus, under the operational conditions of the equipment currently used in Ribeirão Preto, the process of inactivation is probably ineffective, since the exposure time to radiation is only 30 min at the average power of approximately 80 W/kg. PMID:17412582

Tonuci, L R S; Paschoalatto, C F P R; Pisani, R

2008-01-01

471

Localization of GAR transformylase in Escherichia coli and mammalian cells  

PubMed Central

Enzymes of the de novo purine biosynthetic pathway may form a multienzyme complex to facilitate substrate flux through the ten serial steps constituting the pathway. One likely strategy for complex formation is the use of a structural scaffold such as the cytoskeletal network or subcellular membrane of the cell to mediate protein–protein interactions. To ascertain whether this strategy pertains to the de novo purine enzymes, the localization pattern of the third purine enzyme, glycinamide ribonucleotide transformylase (GAR Tfase) was monitored in live Escherichia coli and mammalian cells. Genes encoding human as well as E. coli GAR Tfase fused with green fluorescent protein (GFP) were introduced into their respective cells with regulated expression of proteins and localization patterns monitored by using confocal fluorescence microscopy. In both instances images showed proteins to be diffused throughout the cytoplasm. Thus, GAR Tfase is not localized to an existing cellular architecture, so this device is probably not used to concentrate the members of the pathway. However, discrete clusters of the pathway may still exist throughout the cytoplasm. PMID:11381136

Gooljarsingh, Lata T.; Ramcharan, Joseph; Gilroy, Simon; Benkovic, Stephen J.

2001-01-01

472

The active transport of carbohydrates by Escherichia coli.  

PubMed

The active transport of carbohydrates by Escherichia coli is discussed with particular reference to (1) identification of an uptake process as 'active transport', (2) nature and control of transport proteins, and (3) mechanisms of energy transduction. (1) The use of substrate analogues, of mutants blocked in metabolism and of subcellular vesicles in the isolation of the transport process from interference by subsequent metabolic reactions is described. Criteria are outlined for establishing that the solute is taken up against a concentration gradient and that this is energy-dependent. Three types of poisons for energy systems that act primarily on respiration, on ATP formation and as uncoupling ('proton conducting') agents are considered. (2) Methods are described for the selection of mutants impaired in the active uptake of specific carbohydrates. (3) Results show that the uptake of galactose, D-fucose and arabinose by appropriate strains of E. coli is inducible, specific and accompanied by proton uptake. Such and other data support a model based on a chemiosmotic theory of active transport. PMID:238808

Henderson, P J; Kornberg, H L

1975-01-01

473

Properties of Escherichia coli Mutants Deficient in Enzymes of Glycolysis  

PubMed Central

Physiological properties of mutants of Escherichia coli defective in glyceraldehyde 3-phosphate dehydrogenase, glycerate 3-phosphate kinase, or enolase are described. Introduction of a lesion in any one of the reversible steps catalyzed by these enzymes impaired both the glycolytic and gluconeogenic capabilities of the cell and generated an obligatory requirement for a source of carbon above the block (gluconeogenic) and one below (oxidative). A mixture of glycerol and succinate supported the growth of these mutants. Mutants lacking glyceraldehyde 3-phosphate dehydrogenase and glycerate 3-phosphate kinase could grow also on glycerol and glyceric acid, and enolase mutants could grow on glycerate and succinate, whereas double mutants lacking the kinase and enolase required l-serine in addition to glycerol and succinate. Titration of cell yield with limiting amounts of glycerol with Casamino Acids in excess, or vice versa, showed the gluconeogenic requirement of a growing culture of E. coli to be one-twentieth of its total catabolic and anabolic needs. Sugars and their derivatives inhibited growth of these mutants on otherwise permissive media. The mutants accumulated glycolytic intermediates above the blocked enzyme on addition of glucose or glycerol to resting cultures. Glucose inhibited growth and induced lysis. These effects could be substantially overcome by increasing the osmotic strength of the growth medium and, in addition, including 5 mM cyclic adenosine 3?,5?-monophosphate therein. This substance countered to a large extent the severe repression of ?-galactosidase synthesis that glucose caused in these mutants. PMID:410789

Irani, Meher H.; Maitra, P. K.

1977-01-01