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Sample records for adherent-invasive escherichia coli

  1. Escherichia coli in chronic inflammatory bowel diseases: An update on adherent invasive Escherichia coli pathogenicity

    Margarita; Martinez-Medina; Librado; Jesus; Garcia-Gil

    2014-01-01

    Escherichia coli(E. coli), and particularly the adherent invasive E. coli(AIEC) pathotype, has been increasingly implicated in the ethiopathogenesis of Crohn’s disease(CD). E. coli strains with similar pathogenic features to AIEC have been associated with other intestinal disorders such as ulcerative colitis, colorectal cancer, and coeliac disease, but AIEC prevalence in these diseases remains largely unexplored. Since AIEC was described one decade ago, substantial progress has been made in deciphering its mechanisms of pathogenicity. However, the molecular bases that characterize the phenotypic properties of this pathotype are still not well resolved. A review of studies focused on E. coli populations in inflammatory bowel disease(IBD) is presented here and we discuss about the putative role of this species on each IBD subtype. Given the relevance of AIEC in CD pathogenesis, we present the latest research findings concerning AIEC host-microbe interactions and pathogenicity. We also review the existing data regarding the prevalence and abundance of AIEC in CD and its association with other intestinal diseases from humans and animals, in order to discuss the AIEC disease- and hostspecificity. Finally, we highlight the fact that dietarycomponents frequently found in industrialized countries may enhance AIEC colonization in the gut, which merits further investigation and the implementation of preventative measures.

  2. Adherent-Invasive Escherichia coli Phenotype Displayed by Intestinal Pathogenic E. coli Strains from Cats, Dogs, and Swine ▿

    Martinez-Medina, Margarita; Garcia-Gil, Jesus; Barnich, Nicolas; Lothar H Wieler; Ewers, Christa

    2011-01-01

    The adherent-invasive Escherichia coli (AIEC) pathotype, which has been associated with Crohn's disease, shows similar traits to human and animal extraintestinal pathogenic E. coli (ExPEC) with respect to their phylogenetic origin and virulence gene profiles. Here, we demonstrate that animal ExPEC strains generally do not share the AIEC phenotype. In contrast, this phenotype is very frequent among animal intestinal pathogenic E. coli (InPEC) strains, particularly of feline and canine origin, ...

  3. Adherent-invasive Escherichia coli, strain LF82 disrupts apical junctional complexes in polarized epithelia

    Ossa Juan C

    2009-08-01

    Full Text Available Abstract Background Although bacteria are implicated in the pathogenesis of chronic inflammatory bowel diseases (IBD, mechanisms of intestinal injury and immune activation remain unclear. Identification of adherent-invasive Escherichia coli (AIEC strains in IBD patients offers an opportunity to characterize the pathogenesis of microbial-induced intestinal inflammation in IBD. Previous studies have focused on the invasive phenotype of AIEC and the ability to replicate and survive in phagocytes. However, the precise mechanisms by which these newly identified microbes penetrate the epithelial lining remain to be clarified. Therefore, the aim of this study was to delineate the effects of AIEC, strain LF82 (serotype O83:H1 on model polarized epithelial monolayers as a contributor to intestinal injury in IBD. Results Infection of T84 and Madin-Darby Canine Kidney-I polarized epithelial cell monolayers with AIEC, strain LF82 led to a reduction in transepithelial electrical resistance and increased macromolecular (10 kilodalton dextran flux. Basolateral AIEC infection resulted in more severe disruption of the epithelial barrier. Increased permeability was accompanied by a redistribution of the tight junction adaptor protein, zonula occludens-1, demonstrated by confocal microscopy and formation of gaps between cells, as shown by transmission electron microscopy. After 4 h of infection of intestine 407 cells, bacteria replicated in the cell cytoplasm and were enclosed in membrane-bound vesicles positive for the late endosomal marker, LAMP1. Conclusion These findings indicate that AIEC, strain LF82 disrupts the integrity of the polarized epithelial cell barrier. This disruption enables bacteria to penetrate into the epithelium and replicate in the host cell cytoplasm. These findings provide important links between microbes related to IBD, the intestinal epithelial cell barrier and disease pathogenesis.

  4. Adherent Invasive Escherichia coli Strains from Patients with Crohn's Disease Survive and Replicate within Macrophages without Inducing Host Cell Death

    Glasser, Anne-Lise; Boudeau, Jerome; Barnich, Nicolas; Perruchot, Marie-Helene; Colombel, Jean-Frederic; Darfeuille-Michaud, Arlette

    2001-01-01

    Escherichia coli strains recovered from Crohn's disease (CD) lesions are able to adhere to and invade cultured intestinal epithelial cells. We analyzed the behavior within macrophages of adherent invasive E. coli (AIEC) strains isolated from patients with CD. All the 15 AIEC strains tested were able to replicate extensively within J774-A1 cells: the numbers of intracellular bacteria increased 2.2- to 74.2-fold at 48 h over that at 1 h postinfection. By use of murine peritoneal macrophages and...

  5. A Role for the RNA Chaperone Hfq in Controlling Adherent-Invasive Escherichia coli Colonization and Virulence

    Simonsen, Karina T; Nielsen, Gorm; Bjerrum, Janni Vester;

    2011-01-01

    Adherent-invasive Escherichia coli (AIEC) has been linked with the onset and perpetuation of inflammatory bowel diseases. The AIEC strain LF82 was originally isolated from an ileal biopsy from a patient with Crohn's disease. The pathogenesis of LF82 results from its abnormal adherence to and subs...... in mediating bacterial adaptation. This study highlights the usefulness of simple non-mammalian infection systems for the identification and analysis of bacterial virulence factors....... LF82 virulence determinants but was abolished by deletion of the LF82 hfq gene, which encodes an RNA chaperone involved in mediating posttranscriptional gene regulation by small non-coding RNAs. This finding reveals that important aspects of LF82 pathogenesis are controlled at the posttranscriptional...... level by riboregulation. The role of Hfq in LF82 virulence was independent of its function in regulating RpoS and RpoE activity. Further, LF82Δhfq mutants were non-motile, impaired in cell invasion and highly sensitive to various chemical stress conditions, reinforcing the multifaceted function of Hfq...

  6. Adherent invasive Escherichia coli strains from patients with Crohn's disease survive and replicate within macrophages without inducing host cell death.

    Glasser, A L; Boudeau, J; Barnich, N; Perruchot, M H; Colombel, J F; Darfeuille-Michaud, A

    2001-09-01

    Escherichia coli strains recovered from Crohn's disease (CD) lesions are able to adhere to and invade cultured intestinal epithelial cells. We analyzed the behavior within macrophages of adherent invasive E. coli (AIEC) strains isolated from patients with CD. All the 15 AIEC strains tested were able to replicate extensively within J774-A1 cells: the numbers of intracellular bacteria increased 2.2- to 74.2-fold at 48 h over that at 1 h postinfection. By use of murine peritoneal macrophages and human monocyte-derived-macrophages, the reference AIEC strain LF82 was confirmed to be able to survive intracellularly. Transmission electron micrographs of AIEC LF82-infected macrophages showed that at 24 h postinfection, infected cells harbored large vacuoles containing numerous bacteria, as a result of the fusion of several vacuoles occurring after 8 h postinfection. No lactate dehydrogenase (LDH) release, no sign of DNA fragmentation or degradation, and no binding to fluorescein isothlocyanate-labeled annexin V were observed with LF82-infected J774-A1 cells, even after 24 h postinfection. LF82-infected J774-A1 cells secreted 2.7-fold more tumor necrosis factor alpha (TNF-alpha) than cells stimulated with 1 microg of lipopolysaccharide (LPS)/ml. No release of interleukin-1beta was observed with LPS-prestimulated J774-A1 cells infected with AIEC LF82. These findings showed that (i) AIEC strains are able to survive and to replicate within macrophages, (ii) AIEC LF82 replication does not induce any cell death of the infected cells, and (iii) LF82-infected J774-A1 cells release high levels of TNF-alpha. These properties could be related to some features of CD and particularly to granuloma formation, one of the hallmarks of CD lesions. PMID:11500426

  7. A role for the RNA chaperone Hfq in controlling adherent-invasive Escherichia coli colonization and virulence.

    Karina T Simonsen

    Full Text Available Adherent-invasive Escherichia coli (AIEC has been linked with the onset and perpetuation of inflammatory bowel diseases. The AIEC strain LF82 was originally isolated from an ileal biopsy from a patient with Crohn's disease. The pathogenesis of LF82 results from its abnormal adherence to and subsequent invasion of the intestinal epithelium coupled with its ability to survive phagocytosis by macrophages once it has crossed the intestinal barrier. To gain further insight into AIEC pathogenesis we employed the nematode Caenorhabditis elegans as an in vivo infection model. We demonstrate that AIEC strain LF82 forms a persistent infection in C. elegans, thereby reducing the host lifespan significantly. This host killing phenotype was associated with massive bacterial colonization of the nematode intestine and damage to the intestinal epithelial surface. C. elegans killing was independent of known LF82 virulence determinants but was abolished by deletion of the LF82 hfq gene, which encodes an RNA chaperone involved in mediating posttranscriptional gene regulation by small non-coding RNAs. This finding reveals that important aspects of LF82 pathogenesis are controlled at the posttranscriptional level by riboregulation. The role of Hfq in LF82 virulence was independent of its function in regulating RpoS and RpoE activity. Further, LF82Δhfq mutants were non-motile, impaired in cell invasion and highly sensitive to various chemical stress conditions, reinforcing the multifaceted function of Hfq in mediating bacterial adaptation. This study highlights the usefulness of simple non-mammalian infection systems for the identification and analysis of bacterial virulence factors.

  8. The Crohn's disease-associated adherent-invasive Escherichia coli strain LF82 replicates in mature phagolysosomes within J774 macrophages.

    Bringer, Marie-Agnès; Glasser, Anne-Lise; Tung, Ching-Hsuan; Méresse, Stéphane; Darfeuille-Michaud, Arlette

    2006-03-01

    Adherent-invasive Escherichia coli (AIEC) bacteria isolated from Crohn's disease patients are able to extensively replicate within macrophages in large vacuoles. The mechanism by which AIEC bacteria survive within phagocytic cells is unknown. This report describes the maturation of AIEC LF82-containing phagosomes within J774 macrophages. LF82-containing phagosomes traffic through the endocytic pathway as shown by the sequential acquisition and loss of EEA1 and Rab7 and by accumulation of Lamp-1, Lamp-2 and cathepsin D. We demonstrated that AIEC LF82-containing phagosomes mature into active phagolysosomes where bacteria are exposed to low pH and to the degradative activity of cathepsin D. Finally, we showed that an acidic environment is necessary for replication of AIEC LF82 bacteria within J774 macrophages. Thus, evidence is provided that AIEC LF82 bacteria do not escape from the endocytic pathway but undergo normal interaction with host endomembrane organelles and replicate within acidic and cathepsin D-positive vacuolar phagolysosomes. PMID:16469058

  9. CARD15 variants determine a disturbed early response of monocytes to adherent-invasive Escherichia coli strain LF82 in Crohn's disease.

    Peeters, H; Bogaert, S; Laukens, D; Rottiers, P; De Keyser, Filip; Darfeuille-Michaud, A; Glasser, A-L; Elewaut, D; De Vos, M

    2007-06-01

    Caspase activation and recruitment domain 15 (CARD15) and Toll-like receptor 4 (TLR4) are respectively intracellular and membrane-bound receptors for bacterial cell wall components [respectively muramyl dipeptide (MDP) and lipopolysaccharide (LPS)]. Polymorphisms in CARD15 and TLR4 have been linked with Crohn's disease (CD). Adherent-invasive Escherichia coli (AIEC) strains with particular adhesion and invasion characteristics have been specifically associated with CD ileal mucosa. The aim of this study was to investigate the functional impact of these polymorphisms on monocytes in patients with CD, in response to MDP, LPS and AIEC strain LF82. Monocytes were isolated from 40 patients with CD using magnetic cell sorting, stimulated with LPS or MDP or infected with AIEC. IL-1beta, IL-6, IL-8, IL-10, IL-12 and tumour necrosis factor alpha induction was assessed using quantitative real time-polymerase chain reaction, Cytometric Bead Array and ELISA. Bacterial intracellular survival and replication was assessed using a gentamicin protection assay. Results were linked with the presence of CARD15 and TLR4 polymorphisms. Monocytes of patients with CARD15 polymorphisms showed an early reduced cytokine response (IL-1beta, IL-6 and IL-10) to infection with AIEC, which was restored after 20 h. A gene-dose effect was seen, comparing wild-types, heterozygotes and homozygotes. We found no differences in intracellular survival and replication of AIEC. Heterozygous carriage of TLR4 polymorphisms did not influence monocyte response. In conclusion, patients with CD carrying CARD15 polymorphisms show a disturbed early inflammatory monocyte response after infection with AIEC strain LF82. For the first time, a functional defect was detected in single heterozygous carriers. These findings reflect the potential role of a genetically altered host response to disease-related bacteria in the pathogenesis of CD. PMID:17504508

  10. Carrageenan Gum and Adherent Invasive Escherichia coli in a Piglet Model of Inflammatory Bowel Disease: Impact on Intestinal Mucosa-associated Microbiota.

    Munyaka, Peris M; Sepehri, Shadi; Ghia, Jean-Eric; Khafipour, Ehsan

    2016-01-01

    Inflammatory bowel diseases (IBD) including Crohn's disease (CD), and ulcerative colitis (UC), are chronic conditions characterized by chronic intestinal inflammation. Adherent invasive Escherichia coli (AIEC) pathotype has been increasingly implicated in the etiopathogenesis of IBD. In a 21-day study, we investigated the effects of AIEC strain UM146 inoculation on microbiota profile of the ileal, cecal, ascending and descending colon in a pig model of experimental colitis. Carrageenan gum (CG) was used to induce colitis in weaner piglets whereas AIEC strain UM146 previously isolated from a CD patient was included to investigate a cause or consequence effect in IBD. Treatments were: (1) control; (2) CG; (3) AIEC strain UM146; and (4) CG+UM146. Pigs in groups 2 and 4 received 1% CG in drinking water from day 1 of the study while pigs in groups 3 and 4 were inoculated with UM146 on day 8. Following euthanization on day 21, tissue mucosal scrapings were collected and used for DNA extraction. The V4 region of bacterial 16S rRNA gene was then subjected to Illumina sequencing. Microbial diversity, composition, and the predicted functional metagenome were determined in addition to short chain fatty acids profiles in the digesta and inflammatory cytokines in the intestinal tissue. CG-induced colitis decreased bacterial species richness and shifted community composition. At the phylum level, an increase in Proteobacteria and Deferribacteres and a decrease in Firmicutes, Actinobacteria, and Bacteroidetes were observed in CG and CGUM146 compared to control and UM146. The metabolic capacity of the microbiome was also altered in CG and CGUM146 compared to UM146 and control in the colon. We demonstrated that CG resulted in bacterial dysbiosis and shifted community composition similar to what has been previously observed in IBD patients. However, AIEC strain UM146 alone did not cause any clear changes compared to CG or control in our experimental IBD pig model. PMID:27092122

  11. The Oxidoreductase DsbA Plays a Key Role in the Ability of the Crohn's Disease-Associated Adherent-Invasive Escherichia coli Strain LF82 To Resist Macrophage Killing▿

    Bringer, Marie-Agnès; Rolhion, Nathalie; Glasser, Anne-Lise; Darfeuille-Michaud, Arlette

    2007-01-01

    Adherent-invasive Escherichia coli (AIEC) isolated from Crohn's disease patients is able to adhere to and invade intestinal epithelial cells and to replicate in mature phagolysosomes within macrophages. Here, we show that the dsbA gene, encoding a periplasmic oxidoreductase, was required for AIEC strain LF82 to adhere to intestinal epithelial cells and to survive within macrophages. The LF82-ΔdsbA mutant did not express flagella and, probably as a consequence of this, did not express type 1 p...

  12. Crohn’s disease-associated adherent-invasive E. coli are selectively favoured by impaired autophagy to replicate intracellularly

    Lapaquette, Pierre; Glasser, Anne-Lise; Huett, Alan; Xavier, Ramnik J.; Darfeuille-Michaud, Arlette

    2009-01-01

    Ileal lesions in Crohn’s disease (CD) patients are colonized by pathogenic adherent-invasive Escherichia coli (AIEC) able to invade and to replicate within intestinal epithelial cells. Recent genome-wide association studies have highlighted the autophagy pathway as being associated with CD risk. In the present study we investigated whether defects in autophagy enhance replication of commensal and pathogenic Escherichia coli and CD associated AIEC. We show that functional autophagy limits intr...

  13. The oxidoreductase DsbA plays a key role in the ability of the Crohn's disease-associated adherent-invasive Escherichia coli strain LF82 to resist macrophage killing.

    Bringer, Marie-Agnès; Rolhion, Nathalie; Glasser, Anne-Lise; Darfeuille-Michaud, Arlette

    2007-07-01

    Adherent-invasive Escherichia coli (AIEC) isolated from Crohn's disease patients is able to adhere to and invade intestinal epithelial cells and to replicate in mature phagolysosomes within macrophages. Here, we show that the dsbA gene, encoding a periplasmic oxidoreductase, was required for AIEC strain LF82 to adhere to intestinal epithelial cells and to survive within macrophages. The LF82-DeltadsbA mutant did not express flagella and, probably as a consequence of this, did not express type 1 pili. The role of DsbA in adhesion is restricted to the loss of flagella and type 1 pili, as forced contact between bacteria and cells and induced expression of type 1 pili restored the wild-type phenotype. In contrast, the dsbA gene is essential for AIEC LF82 bacteria to survive within macrophages, irrespective of the loss of flagella and type 1 pilus expression, and the survival ability of LF82-DeltadsbA was as low as that of the nonpathogenic E. coli K-12, which was efficiently killed by macrophages. We also provide evidence that the dsbA gene is needed for LF82 bacteria to grow and survive in an acidic and nutrient-poor medium that partly mimics the harsh environment of the phagocytic vacuole. In addition, under such stress conditions dsbA transcription is highly up-regulated. Finally, the CpxRA signaling pathway does not play a role in regulation of dsbA expression in AIEC LF82 bacteria under conditions similar to those of mature phagolysosomes. PMID:17449627

  14. Crohn's disease-associated adherent-invasive E. coli are selectively favoured by impaired autophagy to replicate intracellularly.

    Lapaquette, Pierre; Glasser, Anne-Lise; Huett, Alan; Xavier, Ramnik J; Darfeuille-Michaud, Arlette

    2010-01-01

    Ileal lesions in Crohn's disease (CD) patients are colonized by pathogenic adherent-invasive Escherichia coli (AIEC) able to invade and to replicate within intestinal epithelial cells. Recent genome-wide association studies have highlighted the autophagy pathway as being associated with CD risk. In the present study we investigated whether defects in autophagy enhance replication of commensal and pathogenic Escherichia coli and CD-associated AIEC. We show that functional autophagy limits intracellular AIEC replication and that a subpopulation of the intracellular bacteria is located within LC3-positive autophagosomes. In IRGM and ATG16L1 deficient cells intracellular AIEC LF82 bacteria have enhanced replication. Surprisingly autophagy deficiency did not interfere with the ability of intracellular bacteria to survive and/or replicate for any other E. coli strains tested, including non-pathogenic, environmental, commensal, or pathogenic strains involved in gastro enteritis. Together these findings demonstrate a central role for autophagy restraining Adherent-Invasive E. coli strains associated with ileal CD. AIEC infection in patients with polymorphisms in autophagy genes may have a significant impact on the outcome of intestinal inflammation. PMID:19747213

  15. Activation of the EIF2AK4-EIF2A/eIF2α-ATF4 pathway triggers autophagy response to Crohn disease-associated adherent-invasive Escherichia coli infection.

    Bretin, Alexis; Carrière, Jessica; Dalmasso, Guillaume; Bergougnoux, Agnès; B'chir, Wafa; Maurin, Anne-Catherine; Müller, Stefan; Seibold, Frank; Barnich, Nicolas; Bruhat, Alain; Darfeuille-Michaud, Arlette; Nguyen, Hang Thi Thu

    2016-05-01

    The intestinal mucosa of Crohn disease (CD) patients is abnormally colonized by adherent-invasive E. coli (AIEC). Upon AIEC infection, autophagy is induced in host cells to restrain bacterial intracellular replication. The underlying mechanism, however, remains unknown. Here, we investigated the role of the EIF2AK4-EIF2A/eIF2α-ATF4 pathway in the autophagic response to AIEC infection. We showed that infection of human intestinal epithelial T84 cells with the AIEC reference strain LF82 activated the EIF2AK4-EIF2A-ATF4 pathway, as evidenced by increased phospho-EIF2AK4, phospho-EIF2A and ATF4 levels. EIF2AK4 depletion inhibited autophagy activation in response to LF82 infection, leading to increased LF82 intracellular replication and elevated pro-inflammatory cytokine production. Mechanistically, EIF2AK4 depletion suppressed the LF82-induced ATF4 binding to promoters of several autophagy genes including MAP1LC3B, BECN1, SQSTM1, ATG3 and ATG7, and this subsequently inhibited transcription of these genes. LF82 infection of wild-type (WT), but not eif2ak4(-/-), mice activated the EIF2AK4-EIF2A-ATF4 pathway, inducing autophagy gene transcription and autophagy response in enterocytes. Consequently, eif2ak4(-/-) mice exhibited increased intestinal colonization by LF82 bacteria and aggravated inflammation compared to WT mice. Activation of the EIF2AK4-EIF2A-ATF4 pathway was observed in ileal biopsies from patients with noninflamed CD, and this was suppressed in inflamed CD, suggesting that a defect in the activation of this pathway could be one of the mechanisms contributing to active disease. In conclusion, we show that activation of the EIF2AK4-EIF2A-ATF4 pathway upon AIEC infection serves as a host defense mechanism to induce functional autophagy to control AIEC intracellular replication. PMID:26986695

  16. Identification of Candidate Adherent-Invasive E. coli Signature Transcripts by Genomic/Transcriptomic Analysis.

    Yuanhao Zhang

    Full Text Available Adherent-invasive Escherichia coli (AIEC strains are detected more frequently within mucosal lesions of patients with Crohn's disease (CD. The AIEC phenotype consists of adherence and invasion of intestinal epithelial cells and survival within macrophages of these bacteria in vitro. Our aim was to identify candidate transcripts that distinguish AIEC from non-invasive E. coli (NIEC strains and might be useful for rapid and accurate identification of AIEC by culture-independent technology. We performed comparative RNA-Sequence (RNASeq analysis using AIEC strain LF82 and NIEC strain HS during exponential and stationary growth. Differential expression analysis of coding sequences (CDS homologous to both strains demonstrated 224 and 241 genes with increased and decreased expression, respectively, in LF82 relative to HS. Transition metal transport and siderophore metabolism related pathway genes were up-regulated, while glycogen metabolic and oxidation-reduction related pathway genes were down-regulated, in LF82. Chemotaxis related transcripts were up-regulated in LF82 during the exponential phase, but flagellum-dependent motility pathway genes were down-regulated in LF82 during the stationary phase. CDS that mapped only to the LF82 genome accounted for 747 genes. We applied an in silico subtractive genomics approach to identify CDS specific to AIEC by incorporating the genomes of 10 other previously phenotyped NIEC. From this analysis, 166 CDS mapped to the LF82 genome and lacked homology to any of the 11 human NIEC strains. We compared these CDS across 13 AIEC, but none were homologous in each. Four LF82 gene loci belonging to clustered regularly interspaced short palindromic repeats region (CRISPR--CRISPR-associated (Cas genes were identified in 4 to 6 AIEC and absent from all non-pathogenic bacteria. As previously reported, AIEC strains were enriched for pdu operon genes. One CDS, encoding an excisionase, was shared by 9 AIEC strains. Reverse

  17. Infection strategies of enteric pathogenic Escherichia coli

    Clements, Abigail; Young, Joanna C.; Constantinou, Nicholas; Frankel, Gad

    2012-01-01

    Enteric Escherichia coli (E. coli) are both natural flora of humans and important pathogens causing significant morbidity and mortality worldwide. Traditionally enteric E. coli have been divided into 6 pathotypes, with further pathotypes often proposed. In this review we suggest expansion of the enteric E. coli into 8 pathotypes to include the emerging pathotypes of adherent invasive E. coli (AIEC) and Shiga-toxin producing enteroaggregative E. coli (STEAEC). The molecular mechanisms that all...

  18. CEACAM6 acts as a receptor for adherent-invasive E. coli, supporting ileal mucosa colonization in Crohn disease

    Barnich, N.; Carvalho, FA; Glasser, AL; Darcha, C; Jantscheff, P; Allez, M; Peeters, Harald; Bommelaer, G.; Desrumeaux, P; Colombel, JF; Darfeuille-Michaud, A

    2007-01-01

    The ileal mucosa of Crohn disease (CD) patients is abnormally colonized by adherent-invasive E. coli (AIEC) that are able to adhere to and invade intestinal epithelial cells. Here, we show that CD-associated AIEC strains adhere to the brush border of primary ileal enterocytes isolated from CD patients but not controls without inflammatory bowel disease. AIEC adhesion is dependent on type 1 pili expression on the bacterial surface and on carcinoembryonic antigen–related cell adhesion molecule ...

  19. CEACAM6 acts as a receptor for adherent-invasive E. coli, supporting ileal mucosa colonization in Crohn disease.

    Barnich, Nicolas; Carvalho, Frédéric A; Glasser, Anne-Lise; Darcha, Claude; Jantscheff, Peter; Allez, Matthieu; Peeters, Harald; Bommelaer, Gilles; Desreumaux, Pierre; Colombel, Jean-Frédéric; Darfeuille-Michaud, Arlette

    2007-06-01

    The ileal mucosa of Crohn disease (CD) patients is abnormally colonized by adherent-invasive E. coli (AIEC) that are able to adhere to and invade intestinal epithelial cells. Here, we show that CD-associated AIEC strains adhere to the brush border of primary ileal enterocytes isolated from CD patients but not controls without inflammatory bowel disease. AIEC adhesion is dependent on type 1 pili expression on the bacterial surface and on carcinoembryonic antigen-related cell adhesion molecule 6 (CEACAM6) expression on the apical surface of ileal epithelial cells. We report also that CEACAM6 acts as a receptor for AIEC adhesion and is abnormally expressed by ileal epithelial cells in CD patients. In addition, our in vitro studies show that there is increased CEACAM6 expression in cultured intestinal epithelial cells after IFN-gamma or TNF-alpha stimulation and after infection with AIEC bacteria, indicating that AIEC can promote its own colonization in CD patients. PMID:17525800

  20. Escherichia Coli

    Goodsell, David S.

    2009-01-01

    Diverse biological data may be used to create illustrations of molecules in their cellular context. I describe the scientific results that support a recent textbook illustration of an "Escherichia coli cell". The image magnifies a portion of the bacterium at one million times, showing the location and form of individual macromolecules. Results…

  1. The Probiotic Escherichia coli Nissle 1917 Reduces Pathogen Invasion and Modulates Cytokine Expression in Caco-2 Cells Infected with Crohn's Disease-Associated E. coli LF82 ▿

    Huebner, Claudia; Ding, Yaoyao; Petermann, Ivonne; Knapp, Christoph; Ferguson, Lynnette R.

    2011-01-01

    Increased numbers of adherent invasive Escherichia coli (AIEC) have been found in Crohn's disease (CD) patients. In this report, we investigate the potential of the probiotic Escherichia coli Nissle 1917 (EcN) to reduce features associated with AIEC pathogenicity in an already established infection with AIEC reference strain LF82.

  2. Uropathogenic Escherichia coli Flagella Aid in Efficient Urinary Tract Colonization

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

    2005-01-01

    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 adherence, invasion, intracellular bacterial community (IBC) formation, and dispersal (fluxing) from the intracellular environment. IBC dispersal is a key step that results in the spread of bacteria over the epithelial surface to initiate additional rounds of IBC formation. We investigate...

  3. Ex vivo intestinal adhesion of Escherichia coli LF82 in Crohn's disease

    Jensen, Stina Rikke; Fink, Lisbeth Nielsen; Nielsen, Ole Haagen;

    2011-01-01

    Adherent-invasive Escherichia coli (AIEC) are reported to inhabit the gut mucosa in Crohn's disease (CD), however, little is known about the importance of host factors for the interplay between AIEC and the human gut. To examine if differences in bacterial adhesion patterns are disease associated...

  4. Taxonomy Icon Data: Escherichia coli [Taxonomy Icon

    Full Text Available Escherichia coli Escherichia coli Escherichia_coli_L.png Escherichia_coli_NL.png Escherichia_coli..._S.png Escherichia_coli_NS.png http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Escherichia+coli...&t=L http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Escherichia+coli&t=NL http://biosciencedbc.jp/taxono...my_icon/icon.cgi?i=Escherichia+coli&t=S http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Escherichia+coli&t=NS ...

  5. Recurrent Escherichia coli bacteremia.

    Maslow, J.N.; Mulligan, M E; Arbeit, R D

    1994-01-01

    Escherichia coli is the most common gram-negative organism associated with bacteremia. While recurrent E. coli urinary tract infections are well-described, recurrent E. coli bacteremia appears to be uncommon, with no episodes noted in multiple series of patients with gram-negative bacteremias. We report on 5 patients with recurrent bloodstream infections identified from a series of 163 patients with E. coli bacteremia. For each patient, the isolates from each episode were analyzed by pulsed-f...

  6. SILAC-based comparative analysis of pathogenic Escherichia coli secretomes

    Boysen, Anders; Borch, Jonas; Krogh, Thøger Jensen;

    2015-01-01

    this study, we grew the pathogenic strains ETEC H10407, AIEC LF82 and the non-pathogenic reference strain E. coli K-12 MG1655 in parallel and used SILAC to compare protein levels in OMVs and culture supernatant. We have identified well-known virulence factors from both AIEC and ETEC, thus validating......Comparative studies of pathogenic bacteria and their non-pathogenic counterparts has led to the discovery of important virulence factors thereby generating insight into mechanisms of pathogenesis. Protein-based antigens for vaccine development are primarily selected among unique virulence...... proteome analysis have the potential to discover both classes of proteins and hence form an important tool for discovering therapeutic targets. Adherent-invasive Escherichia coli (AIEC) and Enterotoxigenic E. coli (ETEC) are pathogenic variants of E. coli which cause intestinal disease in humans. AIEC is...

  7. Recurrent Escherichia coli bacteremia.

    Maslow, J N; Mulligan, M E; Arbeit, R D

    1994-01-01

    Escherichia coli is the most common gram-negative organism associated with bacteremia. While recurrent E. coli urinary tract infections are well-described, recurrent E. coli bacteremia appears to be uncommon, with no episodes noted in multiple series of patients with gram-negative bacteremias. We report on 5 patients with recurrent bloodstream infections identified from a series of 163 patients with E. coli bacteremia. For each patient, the isolates from each episode were analyzed by pulsed-field gel electrophoresis (PFGE) and ribotyping and for the presence of E. coli virulence factors. For each of four patients, the index and recurrent episodes of bacteremia represented the same strain as defined by PFGE, and the strains were found to carry one or more virulence factors. The remaining patient, with two episodes of bloodstream infection separated by a 4-year interval, was infected with two isolates that did not carry any virulence factors and that were clonally related by ribotype analysis but differed by PFGE. All five patients had either a local host defense defect (three patients) or impaired systemic defenses (one patient) or both (one patient). Thus, recurrent E. coli bacteremia is likely to represent a multifactorial process that occurs in patients with impaired host defenses who are infected with virulent isolates. Images PMID:7910828

  8. Ex vivo intestinal adhesion of Escherichia coli LF82 in Crohn’s disease

    Jensen, Stina Rikke; Fink, Lisbeth Nielsen; Nielsen, Ole Haagen; Brynskov, Jørn; Pedersen, Susanne Brix

    2011-01-01

    , the AIEC-prototype strain LF82 was evaluated for its ability to adhere to ileal and colonic biopsies from CD and healthy controls (HC). Moreover, the efficacy of the non-pathogenic E. coli Nissle 1917 (ECN) in averting LF82 adhesion to ileal mucosa was assessed.Similar numbers of LF82 adhered to......Adherent-invasive Escherichia coli (AIEC) are reported to inhabit the gut mucosa in Crohn’s disease (CD), however, little is known about the importance of host factors for the interplay between AIEC and the human gut.To examine if differences in bacterial adhesion patterns are disease associated...

  9. Escherichia coli Uropathogenesis In Vitro

    Andersen, Thomas E; Khandige, Surabhi; Madelung, Michelle;

    2012-01-01

    Uropathogenic Escherichia coli (UPEC) strains are capable of invading bladder epithelial cells (BECs) on the bladder luminal surface. Based primarily on studies in mouse models, invasion is proposed to trigger an intracellular uropathogenic cascade involving intracellular bacterial proliferation...

  10. Mild gut inflammation modulates the proteome of intestinal Escherichia coli.

    Schumann, Sara; Alpert, Carl; Engst, Wolfram; Klopfleisch, Robert; Loh, Gunnar; Bleich, André; Blaut, Michael

    2014-09-01

    Using interleukin 10-deficient (IL-10(-/-) ) and wild-type mice monoassociated with either the adherent-invasive Escherichia coli UNC or the probiotic E. coli Nissle, the effect of a mild intestinal inflammation on the bacterial proteome was studied. Within 8 weeks, IL-10(-/-) mice monoassociated with E. coli UNC exhibited an increased expression of several proinflammatory markers in caecal mucosa. Escherichia coli Nissle-associated IL-10(-/-) mice did not do so. As observed previously for E. coli from mice with acute colitis, glycolytic enzymes were downregulated in intestinal E. coli UNC from IL-10(-/-) mice. In addition, the inhibitor of vertebrate C-type lysozyme, Ivy, was upregulated on messenger RNA (mRNA) and protein level in E. coli Nissle from IL-10(-/-) mice compared with E. coli UNC from these mice. Higher expression of Ivy in E. coli Nissle correlated with an improved growth of this probiotic strain in the presence of lysozyme-ethylenediaminetetraacetic acid (EDTA). By overexpressing Ivy, we demonstrated that Ivy contributes to a higher lysozyme resistance of E. coli, supporting the role of Ivy as a potential fitness factor. However, deletion of Ivy did not alter the growth phenotype of E. coli Nissle in the presence of lysozyme-EDTA, suggesting the existence of additional lysozyme inhibitors that can take over the function of Ivy. PMID:23855897

  11. A phylogenetic group of Escherichia coli associated with active left-sided inflammatory bowel disease

    Petersen, Andreas M; Nielsen, Eva M; Litrup, Eva;

    2009-01-01

    positive ExPEC gene among different groups, 86% were found positive among active IBD patients, significantly more than 13% among inactive IBD patients (p < 0.05), and 11% among healthy controls (p < 0.05). The B2 phylogenetic group was found in a specific cluster based on MLST, but no further separation......BACKGROUND: Escherichia coli have been found in increased numbers in tissues from patients with Inflammatory Bowel Disease (IBD) and adherent-invasive E. coli have been found in resected ileum from patients with Crohn's disease. This study aimed to characterize possible differences in phylogenetic...... 10 healthy controls. Disease activity was evaluated by sigmoidoscopy. Interestingly, E. coli strains of the phylogenetic group B2 were cultured from 60% of patients with IBD compared to 11% of healthy controls (p < 0.05). Furthermore, when comparing the number of E. coli B2 strains with at least one...

  12. Asymptomatic bacteriuria Escherichia coli strains

    Hancock, Viktoria; Nielsen, E.M.; Klemm, Per

    2006-01-01

    Urinary tract infections (UTIs) affect millions of people each year. Escherichia coli is the most common organism associated with asymptomatic bacteriuria (ABU) in humans. Persons affected by ABU may carry a particular E. coli strain for extended periods of time without any symptoms. In contrast to...... uropathogenic E. coli (UPEC) that cause symptomatic UTI, very little is known about the mechanisms by which these strains colonize the urinary tract. Here, we have investigated the growth characteristics in human urine as well as adhesin repertoire of nine ABU strains; the ability of ABU strains to compete...

  13. Fleroxacin resistance in Escherichia coli.

    Chapman, J S; Bertasso, A; Georgopapadakou, N H

    1989-01-01

    Spontaneous fleroxacin-resistant mutants of Escherichia coli K-12 were isolated at a frequency of 10(-10) to 10(-11) mutants per CFU plated. All mutants exhibited quinolone-resistant replicative DNA biosynthesis, and 4 of 11 mutants also had decreased amounts of OmpF or OmpC porin. None of the mutants had changes solely in porin proteins.

  14. Asymptomatic bacteriuria Escherichia coli strains

    Hancock, Viktoria; Nielsen, E.M.; Klemm, Per

    2006-01-01

    Urinary tract infections (UTIs) affect millions of people each year. Escherichia coli is the most common organism associated with asymptomatic bacteriuria (ABU) in humans. Persons affected by ABU may carry a particular E. coli strain for extended periods of time without any symptoms. In contrast to...... uropathogenic E. coli (UPEC) that cause symptomatic UTI, very little is known about the mechanisms by which these strains colonize the urinary tract. Here, we have investigated the growth characteristics in human urine as well as adhesin repertoire of nine ABU strains; the ability of ABU strains to compete...... against the UPEC strain CFT073 was also studied. The different ABU strains displayed a wide variety of the measured characteristics. Half of the ABU strains displayed functional type 1 fimbriae while only one expressed functional P fimbriae. A good correlation between the growth rate of a particular...

  15. Thiol-sensitive promoters of Escherichia coli.

    Javor, G T; Stringer, C D; Ryu, J.

    1988-01-01

    Mu dX(lac) insertion mutants of Escherichia coli CSH50 in which the expression of the lacZ gene was sensitive to the presence of exogenous 1-thioglycerol or dithiothreitol were isolated. Both stimulatory and inhibitory mutants were found. The existence of several thiol-sensitive promoters suggests that exogenous thiols may provoke global stress responses in E. coli.

  16. Infectious endocarditis caused by Escherichia coli

    Lauridsen, Trine Kiilerich; Arpi, Magnus; Fritz-Hansen, Thomas;

    2011-01-01

    Although Escherichia coli is among the most common causes of Gram-negative bacteraemia, infectious endocarditis (IE) due to this pathogen is rare. A 67-y-old male without a previous medical history presented with a new mitral regurgitation murmur and persisting E. coli bacteraemia in spite of broad...

  17. Fimbrial adhesins from extraintestinal Escherichia coli

    Klemm, Per; Hancock, Viktoria; Schembri, Mark A.

    2010-01-01

    Extraintestinal pathogenic Escherichia coli (ExPEC) represent an important subclass of E. coli that cause a wide spectrum of diseases in human and animal hosts. Fimbriae are key virulence factors of ExPEC strains. These long surface located rod-shaped organelles mediate receptor-specific attachment...

  18. Global gene expression in Escherichia coli biofilms

    Schembri, Mark; Kjærgaard, K.; Klemm, Per

    2003-01-01

    antimicrobial treatments and host immune defence responses. Escherichia coli has been used as a model organism to study the mechanisms of growth within adhered communities. In this study, we use DNA microarray technology to examine the global gene expression profile of E. coli during sessile growth compared...

  19. 99mTechnetium labelled Escherichia coli

    Samples of a culture of unlabeled Escherichia coli were incubated with different concentrations of stannous chloride for various time periods. 99mTc (26.0 MBq) was added to each preparation and the results showed a labelling yield of 98% for E. coli. Since the bacterial viability of 99mTc-E. coli and E. coli did not show any statistical differences, these results demonstrate that labelling of E. coli with 99mTc does not modify the bacterial viability, and the radiolabelled bacteria may be a good model to study bacterial translocation

  20. Control of Ribosome Synthesis in Escherichia coli

    Molin, Søren; Meyenburg, K. von; Måløe, O.;

    1977-01-01

    The rate of ribosome synthesis and accumulation in Escherichia coli during the transition after an energy source shift-down was analyzed. The shift was imposed on cultures of stringent and relaxed strains growing in glucose minimal medium by the addition of the glucose analogue {alpha}-methylgluc......The rate of ribosome synthesis and accumulation in Escherichia coli during the transition after an energy source shift-down was analyzed. The shift was imposed on cultures of stringent and relaxed strains growing in glucose minimal medium by the addition of the glucose analogue {alpha...

  1. Hydrogen production by recombinant Escherichia coli strains

    Maeda, Toshinari; Sanchez‐Torres, Viviana; Thomas K Wood

    2012-01-01

    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 increas...

  2. Native valve Escherichia coli endocarditis following urosepsis

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

    2013-01-01

    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.

  3. Beta-alanine synthesis in Escherichia coli.

    Cronan, J. E.

    1980-01-01

    The enzyme, aspartate 1-decarboxylase (L-aspartate 1-carboxy-lyase; EC 4.1.1.15), that catalyzes the reaction aspartate leads to beta-alanine + CO2 was found in extracts of Escherichia coli. panD mutants of E. coli are defective in beta-alanine biosynthesis and lack aspartate 1-decarboxylase. Therefore, the enzyme functions in the biosynthesis of the beta-alanine moiety of pantothenate. The genetic lesion in these mutants is closely linked to the other pantothenate (pan) loci of E. coli K-12.

  4. Comparison of 61 Sequenced Escherichia coli Genomes

    Lukjancenko, Oksana; Wassenaar, T. M.; Ussery, David

    2010-01-01

    Escherichia coli is an important component of the biosphere and is an ideal model for studies of processes involved in bacterial genome evolution. Sixty-one publically available E. coli and Shigella spp. sequenced genomes are compared, using basic methods to produce phylogenetic and proteomics...... the pan-genome and about 80% of a typical genome; some of these variable genes tend to be co-localized on genomic islands. The diversity within the species E. coli, and the overlap in gene content between this and related species, suggests a continuum rather than sharp species borders in this group of...

  5. Cellular chain formation in Escherichia coli biofilms

    Vejborg, Rebecca Munk; Klemm, Per

    2009-01-01

    In this study we report on a novel structural phenotype in Escherichia coli biofilms: cellular chain formation. Biofilm chaining in E. coli K-12 was found to occur primarily by clonal expansion, but was not due to filamentous growth. Rather, chain formation was the result of intercellular......; type I fimbriae expression significantly reduced cellular chain formation, presumably by steric hindrance. Cellular chain formation did not appear to be specific to E coli K-12. Although many urinary tract infection (UTI) isolates were found to form rather homogeneous, flat biofilms, three isolates...

  6. Deuterium incorporation into Escherichia-coli proteins

    Lederer, H.; May, R. P.; Kjems, Jørgen;

    1986-01-01

    -dependent RNA polymerase of Escherichia coli match when RNA polymerase is isolated from cells grown in a medium containing 46% D2O and unlabelled glucose as carbon source. Their contrasts vanish simultaneously in a dialysis buffer containing 65% D2O. An expression was evaluated which allows the calculation of...... the degree of deuteration and match point of any E. coli protein from the D2O content of the growth medium, taking the 2H incorporation into RNA polymerase amino acids to be representative for all amino acids in E. coli proteins. The small-angle scattering results, on which the calculation of the...

  7. Control of Ribosome Synthesis in Escherichia coli

    Molin, Søren; Meyenburg, K. von; Måløe, O.; Trier Hansen, M.; Pato, M. L.

    1977-01-01

    The rate of ribosome synthesis and accumulation in Escherichia coli during the transition after an energy source shift-down was analyzed. The shift was imposed on cultures of stringent and relaxed strains growing in glucose minimal medium by the addition of the glucose analogue {alpha...

  8. Escherichia Coli--Key to Modern Genetics.

    Bregegere, Francois

    1982-01-01

    Mid-nineteenth century work by Mendel on plant hybrids and by Pasteur on fermentation gave birth by way of bacterial genetics to modern-day molecular biology. The bacterium Escherichia Coli has occupied a key position in genetic studies leading from early gene identification with DNA to current genetic engineering using recombinant DNA technology.…

  9. Detection of O antigens in Escherichia coli

    Lipopolysaccharide on the surface of Escherichia coli constitute the O antigens, which are important virulence factors that are targets of both the innate and adaptive immune system and play a major role in host-pathogen interactions. O antigens that are responsible for antigenic specificity of the ...

  10. Progressive segregation of the Escherichia coli chromosome

    Nielsen, Henrik Jørck; Youngren, Brenda; Hansen, Flemming G.;

    2006-01-01

    We have followed the fate of 14 different loci around the Escherichia coli chromosome in living cells at slow growth rate using a highly efficient labelling system and automated measurements. Loci are segregated as they are replicated, but with a marked delay. Most markers segregate in a smooth...

  11. The eclipse period of Escherichia coli

    von Freiesleben, Ulrik; Krekling, Martin A.; Hansen, Flemming G.;

    2000-01-01

    The minimal time between successive initiations on the same origin (the eclipse) in Escherichia coli was determined to be approximately 25-30 min. An inverse relationship was found between the length of the eclipse and the amount of Dam methyltransferase in the cell, indicating that the eclipse...

  12. Leaner and meaner genomes in Escherichia coli

    Ussery, David

    2006-01-01

    A 'better' Escherichia coli K-12 genome has recently been engineered in which about 15% of the genome has been removed by planned deletions. Comparison with related bacterial genomes that have undergone a natural reduction in size suggests that there is plenty of scope for yet more deletions....

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

    Takeda, Yoshifumi

    2011-01-01

    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) ...

  14. Pathogenomics of uropathogenic Escherichia coli

    Agarwal, J.; Srivastava, S.; Singh, M.

    2012-01-01

    Subset of faecal E. coli that can enter, colonize urinary tract and cause infection are known as uropathogenic E. coli (UPEC). UPEC strains act as opportunistic intracellular pathogens taking advantage of host susceptibility using a diverse array of virulence factors. Presence of specific virulence associated genes on genomic/pathogenicity islands and involvement of horizontal gene transfer appears to account for evolution and diversity of UPEC. Recent success in large-scale genome sequencing...

  15. Synergistic effects in mixed Escherichia coli biofilms

    Reisner, A.; Holler, B.M.; Molin, Søren;

    2006-01-01

    pathways governing development of more complex heterogeneous communities. In this study, we established a laboratory model where biofilm-stimulating effects due to interactions between genetically diverse strains of Escherichia coli were monitored. Synergistic induction of biofilm formation resulting from...... the cocultivation of 403 undomesticated E. coli strains with a characterized E. coli K-12 strain was detected at a significant frequency. The survey suggests that different mechanisms underlie the observed stimulation, yet synergistic development of biofilm within the subset of E. coli isolates (n...... = 56) exhibiting the strongest effects was most often linked to conjugative transmission of natural plasmids carried by the E. coli isolates (70%). Thus, the capacity of an isolate to promote the biofilm through cocultivation was (i) transferable to the K-12 strain, (ii) was linked with the acquisition...

  16. Escherichia coli in Europe: An Overview

    Nerino Allocati

    2013-11-01

    Full Text Available Escherichia coli remains one of the most frequent causes of several common bacterial infections in humans and animals. E. coli is the prominent cause of enteritis, urinary tract infection, septicaemia and other clinical infections, such as neonatal meningitis. E. coli is also prominently associated with diarrhoea in pet and farm animals. The therapeutic treatment of E. coli infections is threatened by the emergence of antimicrobial resistance. The prevalence of multidrug-resistant E. coli strains is increasing worldwide principally due to the spread of mobile genetic elements, such as plasmids. The rise of multidrug-resistant strains of E. coli also occurs in Europe. Therefore, the spread of resistance in E. coli is an increasing public health concern in European countries. This paper summarizes the current status of E. coli strains clinically relevant in European countries. Furthermore, therapeutic interventions and strategies to prevent and control infections are presented and discussed. The article also provides an overview of the current knowledge concerning promising alternative therapies against E. coli diseases.

  17. Molecular Characterization of Diarrheagenic Escherichia coli from Libya

    Ali, Mostafa Mohamed M; Mohamed, Zienat Kamel; Klena, John D.; Ahmed, Salwa Fouad; Tarek A.A. Moussa; Ghenghesh, Khalifa Sifaw

    2012-01-01

    Diarrheagenic Escherichia coli (DEC) are important enteric pathogens that cause a wide variety of gastrointestinal diseases, particularly in children. Escherichia coli isolates cultured from 243 diarrheal stool samples obtained from Libyan children and 50 water samples were screened by polymerase chain reaction (PCR) for genes characteristic of enteroaggregative E. coli (EAEC), enteropathogenic E. coli (EPEC), enterotoxigenic E. coli (ETEC), enterohemorrhagic E. coli (EHEC), and enteroinvasiv...

  18. Pathogenomics of uropathogenic Escherichia coli

    J Agarwal

    2012-01-01

    Full Text Available Subset of faecal E. coli that can enter, colonize urinary tract and cause infection are known as uropathogenic E. coli (UPEC. UPEC strains act as opportunistic intracellular pathogens taking advantage of host susceptibility using a diverse array of virulence factors. Presence of specific virulence associated genes on genomic/pathogenicity islands and involvement of horizontal gene transfer appears to account for evolution and diversity of UPEC. Recent success in large-scale genome sequencing and comparative genomics has helped in unravelling UPEC pathogenomics. Here we review recent findings regarding virulence characteristics of UPEC and mechanisms involved in pathogenesis of urinary tract infection.

  19. Ex vivo intestinal adhesion of Escherichia coli LF82 in Crohn’s disease

    Jensen, Stina Rikke; Fink, Lisbeth Nielsen; Nielsen, Ole Haagen;

    2011-01-01

    Adherent-invasive Escherichia coli (AIEC) are reported to inhabit the gut mucosa in Crohn’s disease (CD), however, little is known about the importance of host factors for the interplay between AIEC and the human gut.To examine if differences in bacterial adhesion patterns are disease associated......, the AIEC-prototype strain LF82 was evaluated for its ability to adhere to ileal and colonic biopsies from CD and healthy controls (HC). Moreover, the efficacy of the non-pathogenic E. coli Nissle 1917 (ECN) in averting LF82 adhesion to ileal mucosa was assessed.Similar numbers of LF82 adhered to...... biopsies from CD and HC. A significantly greater LF82 attachment to ileal versus colonic mucosa was found in HC (P <0.01), however, not in CD. ECN did not reduce the adhesion of LF82 to ileal specimens in CD or HC.These results show that enhanced bacterial adhesion ability is unlikely to play any...

  20. Escherichia coli bacteriuria and contraceptive method.

    Hooton, T M; Hillier, S; Johnson, C; Roberts, P L; Stamm, W E

    1991-01-01

    We evaluated the effects of contraceptive method on the occurrence of bacteriuria and vaginal colonization with Escherichia coli in 104 women who were evaluated prior to having sexual intercourse, the morning after intercourse, and 24 hours later. After intercourse, the prevalence of E coli bacteriuria increased slightly in oral contraceptive users but dramatically in both foam and condom users and diaphragm-spermicide users. Twenty-four hours later, the prevalence of bacteriuria remained significantly elevated only in the latter two groups. Similarly, vaginal colonization with E coli was more dramatic and persistent in users of diaphragm-spermicide and foam and condoms. Vaginal colonization with Candida species, enterococci, and staphylococci also increased significantly in diaphragm-spermicide users after intercourse. We conclude that use of the diaphragm with spermicidal jelly or use of a spermicidal foam with a condom markedly alters normal vaginal flora and strongly predisposes users to the development of vaginal colonization and bacteriuria with E coli. PMID:1859519

  1. Dynamics of chromosome segregation in Escherichia coli

    Nielsen, Henrik Jørck

    2007-01-01

    Since the 1960’es the conformation and segregation of the chromosome in Escherichia coli has been a subject of interest for many scientists. However, after 40 years of research, we still know incredibly little about how the chromosome is organized inside the cell, how it manages to duplicate this...... and reliable method enabled us to start the analysis on the distribution of various chromosomal loci inside slowly growing cells. With the actual counting and measuring no longer being any problem we could easily analyze 14 loci distributed on the E.coli chromosome. More than 15.000 cells were...... on the P1 par system. Using the new system, which is based on the pMT1 par system from Yersenia pestis, we labeled loci on opposite sides of the E.coli chromosome simultaneously and were able to show that the E.coli chromosome is organized with one chromosomal arm in each cell half. This astounding...

  2. Infectious endocarditis caused by Escherichia coli

    Lauridsen, Trine Kiilerich; Arpi, Magnus; Fritz-Hansen, Thomas;

    2011-01-01

    Although Escherichia coli is among the most common causes of Gram-negative bacteraemia, infectious endocarditis (IE) due to this pathogen is rare. A 67-y-old male without a previous medical history presented with a new mitral regurgitation murmur and persisting E. coli bacteraemia in spite of broad......-spectrum intravenous antibiotics. Transthoracic and transoesophageal echocardiography revealed a severe mitral endocarditis. E. coli DNA was identified from the mitral valve and the vegetation, and no other pathogen was found. The case was further complicated by spondylodiscitis and bilateral endophthalmitis. Extra......-intestinal pathogenic E. coli (ExPEC) are able to colonize tissue outside the gastrointestinal tract and contain a variety of virulence factors that may enable the pathogens to invade and induce infections in the cardiac endothelia. In these cases echocardiography as the imaging technology is of paramount importance...

  3. Identification and Prevalence of Escherichia coli and Escherichia coli O157: H7 in Foods

    Ancuta Mihaela Rotar

    2013-11-01

    Full Text Available The objective of this study is to investigate the incidence of Escherichia coli in animal and non-animal foods, and mainly the incidence of the serotype O157: H7 producing verotoxin. The presence of common Escherichia coli and Escherichia coli O157: H7 in various foods (of animal and non animal origin was performed in Transylvania area. We analyzed a total of one hundred forty-one samples of minced meat, one hundred twenty-six samples of meat , twenty six samples of meat products, five samples of alcoholic beverages, three samples of seafood, one hundred samples of cheese from pasteurized milk, seventeen samples of butter, four samples of vegetables and one sample of milk powder, using the standard cultural method and Vidas Eco method for E. coli O157: H7 strains. E. coli was identified in 50 samples of minced meat, 55 samples of meat prepared, 4 samples of meat products, 2 samples of alcoholic beverages, 25 samples of cheese from pasteurized milk, 6 samples of butter and 1 sample of vegetables. In this study were not been identified any foods contaminated with the E. coli O157: H7 serotype. The results of this reasearch have demostrated that E. coli wich represents a hygienic indicator of recent food contamination, can be destroyed with heat treatment and hygienic handling of foods. Our country over the years has been among the few countries where the incidence of the E. coli O157: H7 serotype has been minimal.

  4. Designed Phosphoprotein Recognition in Escherichia coli

    Sawyer, Nicholas; Gassaway, Brandon M.; Haimovich, Adrian D.; Isaacs, Farren J.; Rinehart, Jesse; Regan, Lynne

    2014-01-01

    Protein phosphorylation is a central biological mechanism for cellular adaptation to environmental changes. Dysregulation of phosphorylation signaling is implicated in a wide variety of diseases. Thus, the ability to detect and quantify protein phosphorylation is highly desirable for both diagnostic and research applications. Here we present a general strategy for detecting phosphopeptide–protein interactions in Escherichia coli. We first redesign a model tetratricopeptide repeat (TPR) protei...

  5. Endonuclease IV (nfo) mutant of Escherichia coli.

    Cunningham, R P; Saporito, S M; Spitzer, S G; Weiss, B

    1986-01-01

    A cloned gene, designated nfo, caused overproduction of an EDTA-resistant endonuclease specific for apurinic-apyrimidinic sites in DNA. The sedimentation coefficient of the enzyme was similar to that of endonuclease IV. An insertion mutation was constructed in vitro and transferred from a plasmid to the Escherichia coli chromosome. nfo mutants had an increased sensitivity to the alkylating agents methyl methanesulfonate and mitomycin C and to the oxidants tert-butyl hydroperoxide and bleomyci...

  6. Endonuclease III (nth) mutants of Escherichia coli.

    Cunningham, R P; Weiss, B

    1985-01-01

    Two strains that overproduce endonuclease III were found in a colony bank containing hybrid ColE1-Escherichia coli plasmids. The enzyme was identified in crude extracts by the degradation of partially depyrimidinated DNA in the presence of EDTA, by its sedimentation velocity, and by its associated thymine glycol-DNA glycosylase activity. An insertion mutation was produced by cloning the kanamycin-resistance gene of Tn5 into the plasmid copy of the nth gene. The mutation was then transferred t...

  7. Growth of Escherichia coli on nanocrystalline diamond

    Jurková, Blanka; Kozak, Halyna; Artemenko, Anna; Ukraintsev, Egor; Beranová, J.; Konopásek, I.; Kromka, Alexander

    Ostrava: TANGER Ltd, 2015 - (Shrbená, J.; Zbořil, R.), s. 4318 ISBN 9788087294598. [NANOCON 2015. International Conference /7./. Brno (CZ), 14.10.2015-16.10.2015] R&D Projects: GA ČR GA15-01687S Institutional support: RVO:68378271 Keywords : nanocrystalline diamond * bacteria * Escherichia coli * anti-adhesive * CDC Bioreactor Subject RIV: BM - Solid Matter Physics ; Magnetism

  8. Multiplex PCR Assay for Identification of Human Diarrheagenic Escherichia coli

    Toma, Claudia; Lu, Yan; Higa, Naomi; Nakasone, Noboru; Chinen, Isabel; Baschkier, Ariela; Rivas, Marta; Iwanaga, Masaaki

    2003-01-01

    A multiplex PCR assay for the identification of human diarrheagenic Escherichia coli was developed. The targets selected for each category were eae for enteropathogenic E. coli, stx for Shiga toxin-producing E. coli, elt and est for enterotoxigenic E. coli, ipaH for enteroinvasive E. coli, and aggR for enteroaggregative E. coli. This assay allowed the categorization of a diarrheagenic E. coli strain in a single reaction tube.

  9. Action of sodium deoxycholate on Escherichia coli

    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-14C]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

  10. Action of sodium deoxycholate on Escherichia coli

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

    1987-08-01

    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.

  11. Epidemiology and clinical manifestations of enteroaggregative Escherichia coli

    Hebbelstrup Jensen, Betina; Olsen, Katharina E P; Struve, Carsten;

    2014-01-01

    Enteroaggregative Escherichia coli (EAEC) represents a heterogeneous group of E. coli strains. The pathogenicity and clinical relevance of these bacteria are still controversial. In this review, we describe the clinical significance of EAEC regarding patterns of infection in humans, transmission,...

  12. Ethanol production by Escherichia coli KO11; Producao de etanol por Escherichia coli KO11

    Lima, Katia Gianni de Carvalho [Sao Paulo Univ., SP (Brazil). Faculdade de Ciencias Farmaceuticas. Lab. de Microbiologia de Alimentos]. E-mail: gianni@usp.br; Takahashi, Caroline Maki; Alterthum, Flavio [Sao Paulo Univ., SP (Brazil). Inst. de Ciencias Biomedicas. Dept. de Microbiologia

    2002-08-01

    This paper discusses the potential use of Escherichia coli KO11 in production of ethanol, based on observation that this organism can efficiently metabolize sugar complex moistures obtained from the acid hydrolysis of lignocellulose materials such as sugar-cane bagasse, corncob, corn husk, Pinus sp and oak wood.

  13. Expression of maize prolamins in Escherichia Coli

    We have constructed a cDNA expression library of developing corn (Zea manys L.) endosperm using plasmid pUC8 as vector and Escherichia coli strain DH1 as host. The expression library was screened with non-radioactive immunological probes to detect the expression of gamma-zein and alpha-zein. When anti-gamma-zein antibody was used as the probe, 23 colonies gave positive reactions. The lengths of cDNA inserts of the 23 colonies were found to be 250-900 base pairs. When anti-alpha zein antibody was used, however, fewer colonies gave positive reactions. The library was also screened by colony-hybridization with 32P-labeled DNA probes. Based on immunological and hybridization screening of the library and other evidence, we conclude that alpha-zein was either toxic to E. coli cells or rapidly degraded whereas gamma-zein and its fragments were readily expressed. (author)

  14. Global gene expression in Escherichia coli biofilms

    Schembri, Mark; Kjærgaard, K.; Klemm, Per

    2003-01-01

    antimicrobial treatments and host immune defence responses. Escherichia coli has been used as a model organism to study the mechanisms of growth within adhered communities. In this study, we use DNA microarray technology to examine the global gene expression profile of E. coli during sessile growth compared...... with planktonic growth. Genes encoding proteins involved in adhesion (type 1 fimbriae) and, in particular, autoaggregation (Antigen 43) were highly expressed in the adhered population in a manner that is consistent with current models of sessile community development. Several novel gene clusters were...... induced upon the transition to biofilm growth, and these included genes expressed under oxygen-limiting conditions, genes encoding (putative) transport proteins, putative oxidoreductases and genes associated with enhanced heavy metal resistance. Of particular interest was the observation that many of the...

  15. Escherichia coli O157 infections and unpasteurised milk

    Allerberger, F; Wagner, M; Schweiger, P; Rammer, H P; Resch, A; Dierich, M P; Friedrich, A W; Karch, H

    2001-01-01

    We report on two children with Escherichia coli O157 infection, one of whom developed haemolytic uraemic syndrome (HUS). Both had drunk raw cows or goats milk in the week before their illness. Molecular subtyping identified a sorbitol fermenting Escherichia coli O157:H isolate from a dairy cow. This

  16. Chromatin architecture and gene expression in Escherichia coli

    Willenbrock, Hanni; Ussery, David

    2004-01-01

    Two recent genome-scale analyses underscore the importance of DNA topology and chromatin structure in regulating transcription in Escherichia coli.......Two recent genome-scale analyses underscore the importance of DNA topology and chromatin structure in regulating transcription in Escherichia coli....

  17. Escherichia coli clearance after splenic autotransplants

    Background: Splenic autotransplantation seems to be the only alternative for preservation of splenic tissue, after total splenectomy. The present study was carried out to analyze Escherichia coli depuration by mononuclear phagocyte system organs after total splenectomy and splenic autotransplantation. Methods: We utilized an experimental model including young and adult Wistar rats, of both sexes, submitted to total splenectomy and splenic autotransplantation. The evaluation method was intravenous inoculation of a suspension of Escherichia coli labeled with technetium-99m. We analyzed bacteria uptake by mononuclear phagocyte system organs and bacteria remnant in the bloodstream. Results: There was no difference between young and adult animals in bacteria uptake by mononuclear phagocyte system organs. In the comparison of groups, it was found out that the mean percent uptake by spleen and liver of animals in the control group was higher than that observed for animals with splenic implants. However, bacteria uptake in the lung was higher in the splenic implant group than in the control group. Although spleen bacteria uptake in the control group animals has been higher than that of animals in the splenic implant group, the remnant bacteria in the bloodstream was similar. Animals submitted to isolated total splenectomy showed higher bacteria remnant in the bloodstream than animals of the control group or the group submitted to total splenectomy combined with splenic autotransplantation. Conclusion: Our results indicate that autogenous splenic implant is efficacious in bacteria depuration in rats, by means of their macrophages phagocytosis. In addition, it does not modify bacteria removal function of liver and lung

  18. Production of glycoprotein vaccines in Escherichia coli

    Ihssen Julian

    2010-08-01

    Full Text Available Abstract Background Conjugate vaccines in which polysaccharide antigens are covalently linked to carrier proteins belong to the most effective and safest vaccines against bacterial pathogens. State-of-the art production of conjugate vaccines using chemical methods is a laborious, multi-step process. In vivo enzymatic coupling using the general glycosylation pathway of Campylobacter jejuni in recombinant Escherichia coli has been suggested as a simpler method for producing conjugate vaccines. In this study we describe the in vivo biosynthesis of two novel conjugate vaccine candidates against Shigella dysenteriae type 1, an important bacterial pathogen causing severe gastro-intestinal disease states mainly in developing countries. Results Two different periplasmic carrier proteins, AcrA from C. jejuni and a toxoid form of Pseudomonas aeruginosa exotoxin were glycosylated with Shigella O antigens in E. coli. Starting from shake flask cultivation in standard complex medium a lab-scale fed-batch process was developed for glycoconjugate production. It was found that efficiency of glycosylation but not carrier protein expression was highly susceptible to the physiological state at induction. After induction glycoconjugates generally appeared later than unglycosylated carrier protein, suggesting that glycosylation was the rate-limiting step for synthesis of conjugate vaccines in E. coli. Glycoconjugate synthesis, in particular expression of oligosaccharyltransferase PglB, strongly inhibited growth of E. coli cells after induction, making it necessary to separate biomass growth and recombinant protein expression phases. With a simple pulse and linear feed strategy and the use of semi-defined glycerol medium, volumetric glycoconjugate yield was increased 30 to 50-fold. Conclusions The presented data demonstrate that glycosylated proteins can be produced in recombinant E. coli at a larger scale. The described methodologies constitute an important step

  19. Escherichia coli isolated from a Crohn's disease patient adheres, invades, and induces inflammatory responses in polarized intestinal epithelial cells.

    Eaves-Pyles, Tonyia; Allen, Christopher A; Taormina, Joanna; Swidsinski, Alexander; Tutt, Christopher B; Jezek, G Eric; Islas-Islas, Martha; Torres, Alfredo G

    2008-07-01

    Inflammatory diseases of the intestinal tract are a major health concern both in the United States and around the world. Evidence now suggests that a new category of Escherichia coli, designated Adherent Invasive E. coli (AIEC) is highly prevalent in Crohn's Disease (CD) patients. AIEC strains have been shown to colonize and adhere to intestinal epithelial cells (IEC). However, the role AIEC strains play in the induction of an inflammatory response is not known. Therefore, we examined several E. coli strains (designated LF82, O83:H1, 6604 and 6655) that were isolated from CD patients for their ability to induce inflammation in two IEC, Caco-2BBe and T-84 cells. Results showed that each strain had varying abilities to adhere to and invade IEC as well as induced cytokine secretion from polarized IEC. However, E. coli O83:H1 displayed the best characteristics of AIEC strains as compared to the prototype AIEC strain LF82, inducing cytokine secretion from IEC and promoting immune cell migration through IEC. Upon further analysis, E. coli O83:H1 did not harbor virulence genes present in known pathogenic intestinal organisms. Further characterization of E. coli O83:H1 virulence determinants showed that a non-flagellated O83:H1 strain significantly decreased the organism's ability to adhere to and invade both IEC and elicit IEC cytokine secretion compared to the wild type and complemented strains. These findings demonstrate that E. coli O83:H1 possesses the characteristics of the AIEC LF82 strain that may contribute to the low-grade, chronic inflammation observed in Crohn's disease. PMID:17900983

  20. Shigella Strains Are Not Clones of Escherichia coli but Sister Species in the Genus Escherichia

    Zuo, Guanghong; Xu, Zhao; Hao, Bailin

    2012-01-01

    Shigella species and Escherichia coli are closely related organisms. Early phenotyping experiments and several recent molecular studies put Shigella within the species E. coli. However, the whole-genome-based, alignment-free and parameter-free CVTree approach shows convincingly that four established Shigella species, Shigella boydii, Shigella sonnei, Shigella felxneri and Shigella dysenteriae, are distinct from E. coli strains, and form sister species to E. coli within the genus Escherichia. ...

  1. Role of Escherichia coli in Biofuel Production

    Koppolu, Veerendra; Vasigala, Veneela KR

    2016-01-01

    Increased energy consumption coupled with depleting petroleum reserves and increased greenhouse gas emissions have renewed our interest in generating fuels from renewable energy sources via microbial fermentation. Central to this problem is the choice of microorganism that catalyzes the production of fuels at high volumetric productivity and yield from cheap and abundantly available renewable energy sources. Microorganisms that are metabolically engineered to redirect renewable carbon sources into desired fuel products are contemplated as best choices to obtain high volumetric productivity and yield. Considering the availability of vast knowledge in genomic and metabolic fronts, Escherichia coli is regarded as a primary choice for the production of biofuels. Here, we reviewed the microbial production of liquid biofuels that have the potential to be used either alone or in combination with the present-day fuels. We specifically highlighted the metabolic engineering and synthetic biology approaches used to improve the production of biofuels from E. coli over the past few years. We also discussed the challenges that still exist for the biofuel production from E. coli and their possible solutions. PMID:27441002

  2. Regulation of alcohol fermentation by Escherichia coli

    Clark, D.P.

    1989-01-01

    The purpose of this project is to elucidate the way in which the fermentative synthesis of ethanol is regulated in the facultative anaerobe Escherichia coli. We are also investigating the control of other genes required for fermentation and 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 cloning sequence. We have also isolated mutations affecting the fermentative lactate dehydrogenase. 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 the ratio of fermentation products are being investigated by in vivo NMR spectroscopy.

  3. [Population genomic researches of Escherichia coli].

    Wu, Y R; Yang, R F; Cui, Y J

    2016-06-01

    Population genomics, an interdiscipline of genomics and population genetics, is booming in recent years with the rapid growth number of deciphered genomes and revolutionizes the understanding of bacterial population diversity and evolution dynamics. It also largely improves the prevention and control of infectious disease through providing more accurate genotyping and source-tracing results and more comprehensive characteristics of emerging pathogens. In this review, taking one of the best characterized bacteria, Escherichia coli, as model, we reviewed the phylogenetic relationship across its five major populations (designated A, B1, B2, D and E); and summarized researches on molecular mutation rate, selection signals, and patterns of adaptive evolution. We also described the application of population genomics in responding against large-scale outbreaks of E. coli O157:H7 and E. coli O104:H4. These results indicated that, although being a novel discipline, population genomics has played an important role in deciphering bacterial population structures, exploring evolutionary patterns and combating emerging infectious diseases. PMID:27256740

  4. Role of Escherichia coli in Biofuel Production.

    Koppolu, Veerendra; Vasigala, Veneela Kr

    2016-01-01

    Increased energy consumption coupled with depleting petroleum reserves and increased greenhouse gas emissions have renewed our interest in generating fuels from renewable energy sources via microbial fermentation. Central to this problem is the choice of microorganism that catalyzes the production of fuels at high volumetric productivity and yield from cheap and abundantly available renewable energy sources. Microorganisms that are metabolically engineered to redirect renewable carbon sources into desired fuel products are contemplated as best choices to obtain high volumetric productivity and yield. Considering the availability of vast knowledge in genomic and metabolic fronts, Escherichia coli is regarded as a primary choice for the production of biofuels. Here, we reviewed the microbial production of liquid biofuels that have the potential to be used either alone or in combination with the present-day fuels. We specifically highlighted the metabolic engineering and synthetic biology approaches used to improve the production of biofuels from E. coli over the past few years. We also discussed the challenges that still exist for the biofuel production from E. coli and their possible solutions. PMID:27441002

  5. The cobalamin (coenzyme B12) biosynthetic genes of Escherichia coli.

    Lawrence, J. G.; Roth, J R

    1995-01-01

    The enteric bacterium Escherichia coli synthesizes cobalamin (coenzyme B12) only when provided with the complex intermediate cobinamide. Three cobalamin biosynthetic genes have been cloned from Escherichia coli K-12, and their nucleotide sequences have been determined. The three genes form an operon (cob) under the control of several promoters and are induced by cobinamide, a precursor of cobalamin. The cob operon of E. coli comprises the cobU gene, encoding the bifunctional cobinamide kinase...

  6. Diarrheagenic Escherichia coli Markers and Phenotypes among Fecal E. coli Isolates Collected from Nicaraguan Infants ▿

    Reyes, Daniel; Vilchez, Samuel; Paniagua, Margarita; Colque-Navarro, Patricia; Weintraub, Andrej; Möllby, Roland; Kühn, Inger

    2010-01-01

    We analyzed the prevalence of diarrheagenic Escherichia coli (DEC) markers and common phenotypes in 2,164 E. coli isolates from 282 DEC-positive samples. Enteropathogenic E. coli (EPEC) and enteroaggregative E. coli (EAEC) were very diverse and were not correlated with diarrhea. Enterotoxigenic E. coli (ETEC) estA and enterohemorrhagic E. coli (EHEC) belonged to a few phenotypes and were significantly correlated with diarrhea.

  7. Cervical celullitis in broiler chickens for Escherichia coli/
    Celulite cervical em frangos de corte causada por Escherichia coli

    Ivens Gomes Guimarães; Milene Martins Berbel; Marcia Marinho Luzardo; Werner Okano; Claudia Yurika Tamehiro; Benito Guimarães de Brito

    2002-01-01

    In this paper was report the isolation of Escherichia coli in broiler chickens with cellulitis in the cervical region. It was carried through the isolation of E. coli of the lesion of cellulitis from broilers and carried through histopathological examination of skin that had characterized the lesion. Focal ulcerations of epidermis, fibrin in dermis and difuse infiltrated by lymphocytes and heterophils on subcutaneous tissues.Neste trabalho, relata-se o isolamento de Escherichia coli em frango...

  8. Glucose-lactose diauxie in Escherichia coli.

    Loomis, W F; Magasanik, B

    1967-04-01

    Growth of Escherichia coli in medium containing glucose, at a concentration insufficient to support full growth, and containing lactose, is diauxic. A mutation in the gene, CR, which determines catabolite repression specific to the lac operon, was found to relieve glucose-lactose but not glucose-maltose diauxie. Furthermore, a high concentration of lactose was shown to overcome diauxie in a CR(+) strain. Studies on the induction of beta-galactosidase by lactose suggested that glucose inhibits induction by 10(-2)m lactose. Preinduction of the lac operon was found to overcome this effect. The ability of glucose to prevent expression of the lac operon by reducing the internal concentration of inducer as well as by catabolite repression is discussed. PMID:5340309

  9. Whole Genome Epidemiological Typing of Escherichia coli

    Kaas, Rolf Sommer

    is in general expensive and to some extent unreliable. Next generation sequencing has quickly become a tool widely available and has enabled even smaller laboratories to do whole genome sequencing (WGS). Having the entire genome available provides the opportunity to create the ultimate typing method. This Ph......D thesis attempts to take the first steps toward such a method. In Kaas I all publicly available E. coli genomes sequenced (186) are analyzed. 1,702 core genes were found in all genomes. 3,051 genes were found in 95% of the genomes. The pan genome was found to consist of 16,373 genes. The overall phylogeny...... was inferred from the core genome and also set into context of the Escherichia genus. The variance within each gene cluster was calculated in order to compare the variance between genes and possibly identify typing targets for further study. The variance scores calculated was also used to compare the three...

  10. Independence of replisomes in Escherichia coli chromosomalreplication

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

    2005-03-13

    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.

  11. Escherichia coli Pathotypes Occupy Distinct Niches in the Mouse Intestine

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

    2014-01-01

    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...

  12. Genomic Comparative Study of Bovine Mastitis Escherichia coli

    Kempf, Florent; Slugocki, Cindy; Blum, Shlomo E.; Leitner, Gabriel; Germon, Pierre

    2016-01-01

    Escherichia coli, one of the main causative agents of bovine mastitis, is responsible for significant losses on dairy farms. In order to better understand the pathogenicity of E. coli mastitis, an accurate characterization of E. coli strains isolated from mastitis cases is required. By using phylogenetic analyses and whole genome comparison of 5 currently available mastitis E. coli genome sequences, we searched for genotypic traits specific for mastitis isolates. Our data confirm that there i...

  13. The Antiadhesive Strategy in Crohn's Disease: Orally Active Mannosides to Decolonize Pathogenic Escherichia coli from the Gut.

    Alvarez Dorta, Dimitri; Sivignon, Adeline; Chalopin, Thibaut; Dumych, Tetiana I; Roos, Goedele; Bilyy, Rostyslav O; Deniaud, David; Krammer, Eva-Maria; de Ruyck, Jérome; Lensink, Marc F; Bouckaert, Julie; Barnich, Nicolas; Gouin, Sébastien G

    2016-05-17

    Blocking the adherence of bacteria to cells is an attractive complementary approach to current antibiotic treatments, which are faced with increasing resistance. This strategy has been particularly studied in the context of urinary tract infections (UTIs), in which the adhesion of pathogenic Escherichia coli strains to uroepithelial cells is prevented by blocking the FimH adhesin expressed at the tips of bacteria organelles called fimbriae. Recently, we extended the antiadhesive concept, showing that potent FimH antagonists can block the attachment of adherent-invasive E. coli (AIEC) colonizing the intestinal mucosa of patients with Crohn's disease (CD). In this work, we designed a small library of analogues of heptyl mannoside (HM), a previously identified nanomolar FimH inhibitor, but one that displays poor antiadhesive effects in vivo. The anomeric oxygen atom was replaced by a sulfur or a methylene group to prevent hydrolysis by intestinal glycosidases, and chemical groups were attached at the end of the alkyl tail. Importantly, a lead compound was shown to reduce AIEC levels in the feces and in the colonic and ileal mucosa after oral administration (10 mg kg(-1) ) in a transgenic mouse model of CD. The compound showed a low bioavailability, preferable in this instance, thus suggesting the possibility of setting up an innovative antiadhesive therapy, based on the water-soluble and non-cytotoxic FimH antagonists developed here, for the CD subpopulation in which AIEC plays a key role. PMID:26946458

  14. Pseudosecretion of Escherichia coli chloramphenicol acetyltransferase by Bacillus subtilis.

    Le Grice, S F; Gentz, R; Bannwarth, W; Kocher, H. P.

    1987-01-01

    Bacillus subtilis harboring the vector 25RBSII secrets an Escherichia coli-derived chloramphenicol acetyltransferase into culture supernatants. The secreted enzyme lacks 18 amino acids; these are removed externally rather than during secretion.

  15. Role of recBC nuclease in Escherichia coli transformation.

    Hoekstra, W P; Bergmans, J E; Zuidweg, E.M.

    1980-01-01

    In Escherichia coli transformation with linear donor deoxyribonucleic acid, the recBC pathway is functional, but genetic analysis shows that the recBC nuclease is deleterious to linear deoxyribonucleic acid.

  16. Heat-stable enterotoxins from Escherichia coli P16.

    Burgess, M N; Mullan, N A; Newsome, P.M.

    1980-01-01

    Escherichia coli P16 infant mouse active heat-stable enterotoxin may be fractionated into two distinct active moieties by ion-exchange chromatography, Sephadex G-25 chromatography, and isoelectric focusing.

  17. A DNA structural atlas for Escherichia coli.

    Pedersen, A G; Jensen, L J; Brunak, S; Staerfeldt, H H; Ussery, D W

    2000-06-16

    We have performed a computational analysis of DNA structural features in 18 fully sequenced prokaryotic genomes using models for DNA curvature, 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 nucleotide composition. To aid this analysis, we have constructed tools that plot structural measures for all positions in a long DNA sequence (e.g. an entire chromosome) in the form of color-coded wheels (http://www.cbs.dtu. dk/services/GenomeAtlas/). We find that these "structural atlases" are useful for the discovery of interesting features that may then be investigated in more depth using statistical methods. From investigation of the E. coli structural atlas, we discovered a genome-wide trend, where an extended region encompassing the terminus displays a high of level curvature, a low level of flexibility, and a low degree of helix stability. The same situation is found in the distantly related Gram-positive bacterium Bacillus subtilis, suggesting that the phenomenon is biologically relevant. Based on a search for long DNA segments where all the independent structural measures agree, we have found a set of 20 regions with identical and very extreme structural properties. Due to their strong inherent curvature, we suggest that these may function as topological domain boundaries by efficiently organizing plectonemically supercoiled DNA. Interestingly, we find that in practically all the investigated eubacterial and archaeal genomes, there is a trend for promoter DNA being more curved, less flexible, and less stable than DNA in coding regions and in intergenic DNA without promoters. This trend is present regardless of the absolute levels of the structural parameters, and we suggest that this may be related to the requirement for helix unwinding during initiation of transcription, or perhaps to the previously observed

  18. The Escherichia coli divisome: born to divide.

    Natale, Paolo; Pazos, Manuel; Vicente, Miguel

    2013-12-01

    Septation in Escherichia coli involves complex molecular mechanisms that contribute to the accuracy of bacterial division. The proto-ring, a complex made up by the FtsZ, FtsA and ZipA proteins, forms at the beginning of the process and directs the assembly of the full divisome. Central to this complex is the FtsZ protein, a GTPase able to assemble into a ring-like structure that responds to several modulatory inputs including mechanisms to position the septum at midcell. The connection with the cell wall synthesising machinery stabilizes the constriction of the cytoplasmic membrane. Although a substantial amount of evidence supports this description, many details on how individual divisome elements are structured or how they function are subjected to controversial interpretations. We discuss these discrepancies arising from incomplete data and from technical difficulties imposed by the small size of bacteria. Future work, including more powerful imaging and reconstruction technologies, will help to clarify the missing details on the architecture and function of the bacterial division machinery. PMID:23962168

  19. Completion of DNA replication in Escherichia coli

    Wendel, Brian M.; Courcelle, Charmain T.; Courcelle, Justin

    2014-01-01

    The mechanism by which cells recognize and complete replicated regions at their precise doubling point must be remarkably efficient, occurring thousands of times per cell division along the chromosomes of humans. However, this process remains poorly understood. Here we show that, in Escherichia coli, the completion of replication involves an enzymatic system that effectively counts pairs and limits cellular replication to its doubling point by allowing converging replication forks to transiently continue through the doubling point before the excess, over-replicated regions are incised, resected, and joined. Completion requires RecBCD and involves several proteins associated with repairing double-strand breaks including, ExoI, SbcDC, and RecG. However, unlike double-strand break repair, completion occurs independently of homologous recombination and RecA. In some bacterial viruses, the completion mechanism is specifically targeted for inactivation to allow over-replication to occur during lytic replication. The results suggest that a primary cause of genomic instabilities in many double-strand-break-repair mutants arises from an impaired ability to complete replication, independent from DNA damage. PMID:25368150

  20. Expression of Treponema pallidum antigens in Escherichia coli K-12.

    Stamm, L V; Folds, J D; Bassford, P J

    1982-01-01

    A colony bank of recombinant plasmids harboring Treponema pallidum DNA inserts has been established in Escherichia coli K-12. By using an in situ immunoassay, we identified four E. coli clones that expressed T. pallidum antigens. Thus, recombinant DNA technology may provide powerful new tools for studying the pathogenesis of T. pallidum infection.

  1. PCR-ELISA detection of Escherichia coli in milk

    Doyle, Sean; Daly, Paul; Collier, T.

    2002-01-01

    Aims: The purpose of this study was to develop a reliable molecular procedure for the detection of Escherichia coli in milk. Methods and Results: Robust and expeditious DNA extraction and PCR techniques were evaluated using Enzyme-Linked Immunosorbent Assay (ELISA) detection of biotin-labelled amplicons to facilitate optimal detection of E. coli DNA. Conclusions: It was found that 5 E. coli colony-forming units (cfu) could be detected per PCR reaction using the PCR-ELISA sys...

  2. Draft Genome Sequence of Uropathogenic Escherichia coli Strain NB8.

    Weng, Xing-Bei; Mi, Zu-Huang; Wang, Chun-Xin; Zhu, Jian-Ming

    2016-01-01

    Escherichia coli NB8 is a clinical pyelonephritis isolate. Here, we report the draft genome sequence of uropathogenic E. coli NB8, which contains drug resistance genes encoding resistance to beta-lactams, aminoglycosides, quinolones, macrolides, colistin, sulfonamide-trimethoprim, and tetracycline. NB8 infects the kidney and bladder, making it an important tool for studying E. coli pathogenesis. PMID:27609920

  3. Findings of Escherichia coli and Enterococcus spp. in homemade cheese

    Tambur Zoran

    2007-01-01

    Full Text Available During the period from February until March 2004, 108 samples of soft cheese originating from markets of Pancevo, Subotica and Belgrade were examined. Microbiological analyses of the cheese samples to the presence of Escherichia coli was performed using methods described in the Regulations on methods for performing microbiological analyses and super analyses of consumer articles, while the presence of bacteria Enteroccocus spp. was performed on the dexter agar. From 108 samples of soft cheese from the territories of Pancevo, Belgrade and Subotica were isolated: Enterococcus spp. from 96% and Escherichia coli from 69%, cheese samples. Verocytotoxic E.coli was not isolated from any of the taken cheese samples.

  4. The versatile strategies of Escherichia coli pathotypes: a mini review

    C. P. Sousa

    2006-01-01

    Full Text Available The widespread species Escherichia coli includes a broad variety of different types, ranging from highly pathogenic strains to avirulent isolates. Few microorganisms are as versatile as E. coli. Pathogenic strains remain a leading cause of severe and persistent infant diarrhea in developing countries. They may be limited to colonization of a mucosal surface or can disseminate throughout the body and have been implicated in urinary tract infection, sepsis/meningitis and gastrointestinal infection. The human gastrointestinal tract is susceptible to diarrheagenic E. coli infections. Escherichia coli have effectively managed to subvert the host cytoskeleton for their own purposes causing substantial diarrheal disease, a major public health problem worldwide. This review deals with the different strategies regarding E. coli as a pathogen and the virulence traits of its pathotypes highlighting the species as a commensal, opportunistic and specialized pathogen.

  5. ESBL-Producing Escherichia coli

    Hertz, Frederik Boetius

    Urinary tract infection (UTI) is one the most common bacterial infections and is regularly treated in primary health care. The most common cause of UTI is extraintestinal pathogenic Escherichia coli (ExPEC) already present in the intestinal microflora, often as the dominating strain. Resistance in...... E.coli is increasing and especially isolates producing Extended-Spectrum Beta-Lactamases (ESBL) have been reported worldwide. Treatment of UTI is usually initiated by the general practitioners and a significant proportion of clinical isolates are now resistant to first line antibiotics. The global...... dissemination of resistant E.coli has in particular been driven by the spread of a few specific E.coli-lineages and it seems that there is a difference between the sequence types found among resistant E.coli, ESBL-producing E.coli and antibiotic susceptible E.coli. The overall objectives of this thesis were to...

  6. Is Escherichia coli urinary tract infection a zoonosis?

    Jacobsen, L.; Garneau, P.; Bruant, G.;

    2012-01-01

    Recently, it has been suggested that the Escherichia coli causing urinary tract infection (UTI) may come from meat and animals. The purpose was to investigate if a clonal link existed between E. coli from animals, meat and UTI patients. Twenty-two geographically and temporally matched B2 E. coli...... and kidney cultures. Further, isolates with the same gene profile also yielded similar bacterial counts in urine, bladder and kidneys. This study showed a clonal link between E. coli from meat and humans, providing solid evidence that UTI is zoonosis. The close relationship between community...

  7. Invasive ability of an Escherichia coli strain isolated from the ileal mucosa of a patient with Crohn's disease.

    Boudeau, J; Glasser, A L; Masseret, E; Joly, B; Darfeuille-Michaud, A

    1999-09-01

    not reveal the presence of any of the genetic determinants encoding EIEC, EPEC, or ETEC proteins involved in bacterial invasion. Thus, these findings show that LF82, which colonized the ileal mucosa of a patient with CD, is a true invasive E. coli strain and suggest the existence of a new potentially pathogenic group of E. coli, which we propose be designated adherent-invasive E. coli. PMID:10456892

  8. Outbreaks of virulent diarrheagenic Escherichia coli - are we in control?

    Werber Dirk; Krause Gérard; Frank Christina; Fruth Angelika; Flieger Antje; Mielke Martin; Schaade Lars; Stark Klaus

    2012-01-01

    Abstract Shiga toxin-producing Escherichia coli (STEC) are the most virulent diarrheagenic E. coli known to date. They can be spread with alarming ease via food as exemplified by a large sprout-borne outbreak of STEC O104:H4 in 2011 that was centered in northern Germany and affected several countries. Effective control of such outbreaks is an important public health task and necessitates early outbreak detection, fast identification of the outbreak vehicle and immediate removal of the suspect...

  9. Outbreaks of virulent diarrheagenic Escherichia coli - are we in control?

    Werber, Dirk; Krause, Gérard; Frank, Christina; Fruth, Angelika; Mielke, Martin; Schaade, Lars; Stark, Klaus

    2012-01-01

    Shiga toxin-producing Escherichia coli (STEC) are the most virulent diarrheagenic E. coli known to date. They can be spread with alarming ease via food as exemplified by a large sprout-borne outbreak of STEC O104:H4 in 2011 that was centered in northern Germany and affected several countries. Effective control of such outbreaks is an important public health task and necessitates early outbreak detection, fast identification of the outbreak vehicle and immediate removal of the suspected fo...

  10. Fundamental study of recombination and recombineering in Escherichia coli

    Sun, Xiaohang; Huang, Yang

    2008-01-01

    Recombination and recombineering systems have been used in Escherichia coli to recombinant DNA sequences. With endonuclease and DNA lipase the bacterial plasmid and target DNA fragment can bind together and recombinant for a new DNA sequences. Red Proteins have been used in recombineering system to perform the function as the enzymes in recombination system, and faster and easier than the other way of recombinant new DNA sequences in E.coli. In this report we get to know the pr...

  11. Differential expression of the Escherichia coli autoaggregation factor antigen 43

    Schembri, Mark; Hjerrild, Louise; Gjermansen, Morten;

    2003-01-01

    Antigen 43 (Ag43) is a self-recognizing surface adhesin found in most Escherichia coli strains. Due to its excellent cell-to-cell aggregation characteristics, Ag43 expression confers clumping and fluffing of cells and promotes biofilm formation. Ag43 expression is repressed by the cellular redox......-forming potential of E. coli. Finally, we demonstrated that Ag43-mediated cell aggregation confers significant protection against hydrogen peroxide killing....

  12. Escherichia coli and Community-acquired Gastroenteritis, Melbourne, Australia

    Robins-Browne, Roy M.; Bordun, Anne-Marie; Tauschek, Marija; Bennett-Wood, Vicki R.; Russell, Jacinta; Oppedisano, Frances; Lister, Nicole A.; Bettelheim, Karl A.; Fairley, Christopher K.; Sinclair, Martha I; Hellard, Margaret E

    2004-01-01

    As part of a study to determine the effects of water filtration on the incidence of community-acquired gastroenteritis in Melbourne, Australia, we examined fecal samples from patients with gastroenteritis and asymptomatic persons for diarrheagenic strains of Escherichia coli. Atypical strains of enteropathogenic E. coli (EPEC) were the most frequently identified pathogens of all bacterial, viral, and parasitic agents in patients with gastroenteritis. Moreover, atypical EPEC were more common i...

  13. Recombinant Production of Human Interleukin 6 in Escherichia coli

    Henrik Nausch; Jana Huckauf; Roswitha Koslowski; Udo Meyer; Inge Broer; Heike Mikschofsky

    2013-01-01

    In this study, we compared basic expression approaches for the efficient expression of bioactive recombinant human interleukin-6 (IL6), as an example for a difficult-to-express protein. We tested these approaches in a laboratory scale in order to pioneer the commercial production of this protein in Escherichia coli (E. coli). Among the various strategies, which were tested under Research and Development (R&D) conditions, aggregation-prone IL6 was solubilized most effectively by co-expressing ...

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

    Rhodes, M W; Kator, H.

    1988-01-01

    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 ...

  15. Role of granulocytes and monocytes in experimental Escherichia coli endocarditis.

    Meddens, M J; Thompson, J.; Bauer, W C; van Furth, R

    1984-01-01

    The role of granulocytes and monocytes during the induction and course of Escherichia coli endocarditis was investigated in rabbits by selectively depleting monocytes from the circulation with the drug VP16-213 and granulocytes and monocytes with nitrogen mustard. For induction, the number of E. coli needed to infect the vegetations in 50% of the rabbits was significantly lower in rabbits with combined granulocytopenia and monocytopenia than in those with selective monocytopenia or in control...

  16. Metabolic and Transcriptional Response to Cofactor Perturbations in Escherichia coli

    Holm, Anders Koefoed; Blank, L.M.; Oldiges, M.;

    2010-01-01

    Metabolic cofactors such as NADH and ATP play important roles in a large number of cellular reactions, and it is of great interest to dissect the role of these cofactors in different aspects of metabolism. Toward this goal, we overexpressed NADH oxidase and the soluble F1-ATPase in Escherichia coli...... general understanding of redox and energy metabolism and should help in developing metabolic engineering strategies in E. coli....

  17. Dissecting the roles of Escherichia coli hydrogenases in biohydrogen production

    Redwood, MD; Mikheenko, IP; Sargent, F.; Macaskie, LE

    2008-01-01

    Escherichia coli can perform at least two modes of anaerobic hydrogen metabolism and expresses at least two types of hydrogenase activity. Respiratory hydrogen oxidation is catalysed by two ‘uptake’ hydrogenase isoenzymes, hydrogenase -1 and -2 (Hyd-1 and -2), and fermentative hydrogen production is catalysed by Hyd-3. Harnessing and enhancing the metabolic capability of E. coli to perform anaerobic mixed-acid fermentation is therefore an attractive approach for bio-hydrogen production ...

  18. Cervical celullitis in broiler chickens for Escherichia coli/ Celulite cervical em frangos de corte causada por Escherichia coli

    Ivens Gomes Guimarães

    2002-05-01

    Full Text Available In this paper was report the isolation of Escherichia coli in broiler chickens with cellulitis in the cervical region. It was carried through the isolation of E. coli of the lesion of cellulitis from broilers and carried through histopathological examination of skin that had characterized the lesion. Focal ulcerations of epidermis, fibrin in dermis and difuse infiltrated by lymphocytes and heterophils on subcutaneous tissues.Neste trabalho, relata-se o isolamento de Escherichia coli em frangos de corte apresentando lesão de celulite na região cervical. Foi realizado o isolamento de E. coli da lesão de celulite e realizado exames histopatológicos que caracterizaram a lesão. Na epiderme foram verificadas lesões ulcerativas, presença de fibrina na derme e infiltração difusa de linfócitos e heterófilos no tecido subcutâneo.

  19. Inactivation of Escherichia Coli in Orange Juice Using Ozone

    Patil, Sonal; Bourke, Paula; Frias, Jesus Maria; Tiwari, Brijesh; Cullen, Patrick

    2009-01-01

    This research investigated the efficacy of gaseous ozone for the inactivation of Escherichia coli ATCC 25922 and NCTC 12900 strains in orange juice. Orange juice inoculated with E. coli (106 CFU mL-1) as a challenge microorganism was treated with ozone at 75-78µg mL-1 for different time periods (0-18 min). The efficacy of ozone for inactivation of both strains of E. coli was evaluated as a function of different juice types: model orange juice, fresh unfiltered juice, juice without pulp, and j...

  20. Escherichia coli O26 IN RAW BUFFALO MILK: PRELIMINARY RESULTS

    A. Rella

    2013-02-01

    Full Text Available Escherichia coli O26 is considered to be one of the most important food-borne pathogen. In this study, 120 buffalo milk samples collected in Lazio and in Apulia regions were tested for the presence of E. coli O26. One buffalo milk sample (0,8% tested positive for E. coli O26; the isolate was positive at the verocytotoxicity test and it showed resistance properties to different antimicrobial classes. These preliminary results highlight the need to monitor the foods of animal origin used for production and eaten by a wide range of persons, respect VTEC organism.

  1. Protein abundance profiling of the Escherichia coli cytosol

    Ishihama, Y.; Schmidt, T.; Rappsilber, J.;

    2008-01-01

    sample. Using a combination of LC-MS/MS approaches with protein and peptide fractionation steps we identified 1103 proteins from the cytosolic fraction of the Escherichia coli strain MC4100. A measure of abundance is presented for each of the identified proteins, based on the recently developed em...... between protein and mRNA abundance in E. coli cells. Conclusion: Abundance measurements for more than 1000 E. coli proteins presented in this work represent the most complete study of protein abundance in a bacterial cell so far. We show significant associations between the abundance of a protein and its...

  2. YeeO from Escherichia coli exports flavins.

    McAnulty, Michael J; Wood, Thomas K

    2014-01-01

    Multidrug and toxic compound extrusion (MATE) proteins help maintain cellular homeostasis by secreting metabolic wastes. Flavins may occur as cellular waste products, with their production and secretion providing potential benefit for industrial applications related to biofuel cells. Here we find that MATE protein YeeO from Escherichia coli exports both flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD). Significant amounts of flavins were trapped intracellularly when YeeO was produced indicating transport limits secretion of flavins. Wild-type E. coli secreted 3 flavins (riboflavin, FMN, and FAD), so E. coli likely produces additional flavin transporters. PMID:25482085

  3. An integrated database to support research on Escherichia coli

    Baehr, A.; Dunham, G.; Matsuda, Hideo; Michaels, G.; Taylor, R.; Overbeek, R.; Rudd, K.E. [National Inst. of Mental Health, Bethesda, MD (United States); Ginsburg, A.; Joerg, D.; Kazic, T. [Washington Univ., St. Louis, MO (United States). Dept. of Genetics; Hagstrom, R.; Zawada, D. [Argonne National Lab., IL (United States); Smith, C.; Yoshida, Kaoru [Lawrence Berkeley Lab., CA (United States)

    1992-01-01

    We have used logic programming to design and implement a prototype database of genomic information for the model bacterial organism Escherichia coli. This report presents the fundamental database primitives that can be used to access and manipulate data relating to the E. coli genome. The present system, combined with a tutorial manual, provides immediate access to the integrated knowledge base for E. coli chromosome data. It also serves as the foundation for development of more user-friendly interfaces that have the same retrieval power and high-level tools to analyze complex chromosome organization.

  4. Molecular Characterization of Diarrheagenic Escherichia coli from Libya

    Ali, Mostafa Mohamed M.; Mohamed, Zienat Kamel; Klena, John D.; Ahmed, Salwa Fouad; Moussa, Tarek A. A.; Ghenghesh, Khalifa Sifaw

    2012-01-01

    Diarrheagenic Escherichia coli (DEC) are important enteric pathogens that cause a wide variety of gastrointestinal diseases, particularly in children. Escherichia coli isolates cultured from 243 diarrheal stool samples obtained from Libyan children and 50 water samples were screened by polymerase chain reaction (PCR) for genes characteristic of enteroaggregative E. coli (EAEC), enteropathogenic E. coli (EPEC), enterotoxigenic E. coli (ETEC), enterohemorrhagic E. coli (EHEC), and enteroinvasive E. coli (EIEC). The DEC were detected in 21 (8.6%) children with diarrhea; 10 (4.1%) cases were identified as EAEC, 3 (1.2%) as EPEC, and 8 (3.3%) were ETEC; EHEC, and EIEC were not detected. All DEC were grouped phylogenetically by PCR with the majority (> 70%) identified as phylogenetic groups A and B1. The EAEC isolates were also tested for eight genes associated with virulence using PCR. Multi-virulence (≥ 3 virulence factors) was found in 50% of EAEC isolates. Isolated EAEC possessed different virulence traits and belonged to different phylogenetic groups indicating their heterogeneity. PMID:22556089

  5. Recent Sensitivity Pattern of Escherichia Coli in Urinary Tract Infection

    R Nalini

    2014-06-01

    Full Text Available The objective of the study is to assess the recent sensitivity pattern of Escherichia coli in Urinary tract infection (UTI.Widespread use of antibiotics has led to the emergence of resistant microorganisms. As the antibiotic sensitivity patterns of the microorganisms are frequently changing, this retrospective analysis was designed to assess the recent antibiotic sensitivity pattern of Escherichia coli (E.coli in urinary tract infection among the human population. Details of 412 urine culture positive reports for E.coli and their antibiotic sensitivity pattern pertaining to the study period of 12months from June 2012 to May 2013 were collected from Central Microbiology Laboratory of Tirunelveli Medical College and the results were statistically analysed. The antibiotics tested for sensitivity were Amikacin, Gentamycin, Ciprofloxacin, Cotrimoxazole, Nitrofurantoin, Ceftazidime, Ceftriaxone and Cefotaxime. The sensitivity pattern of E.coli to antibiotics in UTI were Nitrofurantoin (85.19%, Amikacin (66.50%, Co-trimoxazole(31.31%, Gentamycin (26.90%, Ceftazidime (26.69% ,Ciprofloxacin (22.57%, Cefotaxime (22.30%, Ceftriaxone (17.47%. The study highlighted the re-emergence of E. coli sensitive to Nitrofurantoin and marked resistance of E.coli to Aminoglycoside and third generation Cephalosporins.

  6. Carbon and energy metabolism of atp mutants of Escherichia coli

    Jensen, Peter Ruhdal; Michelsen, Ole

    1992-01-01

    The membrane-bound H+-ATPase plays a key role in free-energy transduction of biological systems. We report how the carbon and energy metabolism of Escherichia coli changes in response to deletion of the atp operon that encodes this enzyme. Compared with the isogenic wild-type strain, the growth...

  7. Genetic Basis of Minicell Formation in Escherichia coli K-12

    1984-01-01

    Hfr- and P1-mediated genetic transfer experiments failed to confirm the presence of a " minA " gene in Escherichia coli K-12, leading to the conclusion that mutation at a single locus, the minB locus, is sufficient to cause minicell production in this species.

  8. Antibiotic treatment of verocytotoxin-producing Escherichia coli (VTEC) infection

    Agger, Morten; Scheutz, Flemming; Villumsen, Steen; Mølbak, Kåre; Petersen, Andreas Munk

    2015-01-01

    OBJECTIVES: A consensus has existed on not to treat verocytotoxin-producing Escherichia coli (VTEC)-infected individuals with antibiotics because of possible subsequent increased risk of developing haemolytic uraemic syndrome (HUS). The aim of this systematic review is to clarify the risk...

  9. Escherichia coli. A sanitary methodology for faecal water pollution tests

    Among the traditional indictors of faecal water pollution, Escherichia coli has shown to fit better with the definition of indicator organism. Till now its recovery has been time-consuming and needs confirmation tests. In this report more rapid and direct methods, based on enzymatic reactions, are presented

  10. DNA supercoiling depends on the phosphorylation potential in Escherichia coli

    Van Workum, M.; van Dooren, S.J.M; Oldenburg, N;

    1996-01-01

    ATP/ADP ratios were varied in different ways and the degree of negative supercoiling was determined in Escherichia coli. Independent of whether the ATP/ADP ratio was reduced by a shift to anaerobic conditions, by addition of protonophore (dinitrophenol) or by potassium cyanide addition, DNA...

  11. Chromosomal replication incompatibility in Dam methyltransferase deficient Escherichia coli cells

    Freiesleben, Ulrik Von

    1996-01-01

    Dam methyltransferase deficient Escherichia coli cells containing minichromosomes were constructed. Free plasmid DNA could not be detected in these cells and the minichromosomes were found to be integrated in multiple copies in the origin of replication (oriC) region of the host chromosome. The...

  12. Escherichia coli and other Enterobacteriaceae: Food poisoning and health effects

    The family Enterobactericeae consists of rod-shaped, Gram-negative, facultatively anaerobic, non-spore forming bacteria and also includes the food-borne pathogens, Cronobacter spp., Escherichia coli, Salmonella enterica, Shigella spp., and Yersinia spp. Illness caused by these pathogens is acquired...

  13. Multidrug-Resistant Escherichia coli in Bovine Animals, Europe.

    Brennan, Evan; Martins, Marta; McCusker, Matthew P; Wang, Juan; Alves, Bruno Martins; Hurley, Daniel; El Garch, Farid; Woehrlé, Frédérique; Miossec, Christine; McGrath, Leisha; Srikumar, Shabarinath; Wall, Patrick; Fanning, Séamus

    2016-09-01

    Of 150 Escherichia coli strains we cultured from specimens taken from cattle in Europe, 3 had elevated MICs against colistin. We assessed all 3 strains for the presence of the plasmid-mediated mcr-1 gene and identified 1 isolate as mcr-1-positive and co-resistant to β-lactam, florfenicol, and fluoroquinolone antimicrobial compounds. PMID:27533105

  14. Differential expression of the Escherichia coli autoaggregation factor antigen 43

    Schembri, Mark; Hjerrild, Louise; Gjermansen, Morten; Klemm, Per

    2003-01-01

    Antigen 43 (Ag43) is a self-recognizing surface adhesin found in most Escherichia coli strains. Due to its excellent cell-to-cell aggregation characteristics, Ag43 expression confers clumping and fluffing of cells and promotes biofilm formation. Ag43 expression is repressed by the cellular redox...

  15. Escherichia coli and virus isolated from ''sticky kits''

    Jørgensen, M.; Scheutz, F.; Strandbygaard, Bertel

    1996-01-01

    A total of 121 Escherichia coli strains isolated from 3-week-old mink kits were serotyped and examined for virulence factors. 56 strains were isolated from healthy kits while 65 were from ''sticky kits''. Among these, 34 different serotypes were detected. No difference in serotypes or the presenc...

  16. Dynamics of Escherichia coli Chromosome Segregation during Multifork Replication

    Nielsen, Henrik Jørck; Youngren, Brenda; Hansen, Flemming G.;

    2007-01-01

    Slowly growing Escherichia coli cells have a simple cell cycle, with replication and progressive segregation of the chromosome completed before cell division. In rapidly growing cells, initiation of replication occurs before the previous replication rounds are complete. At cell division, the...

  17. Molecular characterization of the Escherichia coli asymptomatic bacteriuria strain 83972

    Klemm, Per; Hancock, Viktoria; Ulett, G.C.;

    2006-01-01

    Escherichia coli 83972 is a clinical asymptomatia bacteriuric isolate that is able to colonize the human urinary bladder without inducing an immune response. Here we demonstrate that one of the mechanisms by which this strain has become attenuated is through the mutation of its genes encoding type...

  18. Aging in Escherichia coli: stochasticity, individual heterogeneity and mortality plateaus

    Steiner, Uli

    2014-01-01

    suggested to be involved in aging and senescence, but no mechanism or factor has been unambiguously identified. Here, we report on surprising patterns of aging and senescence from isogenic individual Escherichia coli bacteria grown under identical environmental conditions in a microfluidic device. Such...

  19. FimH-mediated autoaggregation of Escherichia coli

    Schembri, Mark; Christiansen, G.; Klemm, Per

    2001-01-01

    Autoaggregation is a phenomenon thought to contribute to colonization of mammalian hosts by pathogenic bacteria. Type 1 fimbriae are surface organelles of Escherichia coli that mediate D-mannose-sensitive binding to various host surfaces. This binding is conferred by the minor fimbrial component ...

  20. Binding of Divalent Magnesium by Escherichia coli Phosphoribosyl Diphosphate Synthetase

    Willemoës, Martin; Hove-Jensen, Bjarne

    1997-01-01

    The mechanism of binding of the substrates MgATP and ribose 5-phosphate as well as Mg2+ to the enzyme 5-phospho-d-ribosyl a-1-diphosphate synthetase from Escherichia coli has been analyzed. By use of the competive inhibitors of ATP and ribose 5-phosphate binding, a,ß-methylene ATP and (+)-1-a,2-a...

  1. Binding of divalent magnesium by Escherichia coli phosphoribosyl diphosphate synthetase

    Willemoës, Martin; Hove-Jensen, Bjarne

    1997-01-01

    The mechanism of binding of the substrates Mg x ATP and ribose 5-phosphate as well as Mg2+ to the enzyme 5-phospho-D-ribosyl (alpha-1-diphosphate synthetase from Escherichia coli has been analyzed. By use of the competive inhibitors of ATP and ribose 5-phosphate binding, alpha,beta-methylene ATP ...

  2. Cytokine response to Escherichia coli in gnotobiotic pigs

    Šplíchal, Igor; Šplíchalová, Alla; Trebichavský, Ilja

    2008-01-01

    Roč. 53, č. 2 (2008), s. 161-164. ISSN 0015-5632 R&D Projects: GA ČR GA523/05/0249 Institutional research plan: CEZ:AV0Z50200510 Keywords : germ-free pigs * escherichia coli * cytokine response Subject RIV: EE - Microbiology, Virology Impact factor: 1.172, year: 2008

  3. Phylogenetic Group Determination of Escherichia coli Isolated from Animals Samples

    Fernanda Morcatti Coura

    2015-01-01

    Full Text Available This study analyzes the occurrence and distribution of phylogenetic groups of 391 strains of Escherichia coli isolated from poultry, cattle, and water buffalo. The frequency of the phylogroups was A = 19%, B1 = 57%, B2 = 2.3%, C = 4.6%, D = 2.8%, E = 11%, and F = 3.3%. Phylogroups A (P<0.001 and F (P=0.018 were associated with E. coli strains isolated from poultry, phylogroups B1 (P<0.001 and E (P=0.002 were associated with E. coli isolated from cattle, and phylogroups B2 (P=0.003 and D (P=0.017 were associated with E. coli isolated from water buffalo. This report demonstrated that some phylogroups are associated with the host analyzed and the results provide knowledge of the phylogenetic composition of E. coli from domestic animals.

  4. Phylogenetic Group Determination of Escherichia coli Isolated from Animals Samples

    Morcatti Coura, Fernanda; Diniz, Soraia de Araújo; Silva, Marcos Xavier; Mussi, Jamili Maria Suhet; Barbosa, Silvia Minharro; Lage, Andrey Pereira; Heinemann, Marcos Bryan

    2015-01-01

    This study analyzes the occurrence and distribution of phylogenetic groups of 391 strains of Escherichia coli isolated from poultry, cattle, and water buffalo. The frequency of the phylogroups was A = 19%, B1 = 57%, B2 = 2.3%, C = 4.6%, D = 2.8%, E = 11%, and F = 3.3%. Phylogroups A (P < 0.001) and F (P = 0.018) were associated with E. coli strains isolated from poultry, phylogroups B1 (P < 0.001) and E (P = 0.002) were associated with E. coli isolated from cattle, and phylogroups B2 (P = 0.003) and D (P = 0.017) were associated with E. coli isolated from water buffalo. This report demonstrated that some phylogroups are associated with the host analyzed and the results provide knowledge of the phylogenetic composition of E. coli from domestic animals. PMID:26421310

  5. Uji Antibakteri Ekstak Daun Sirsak (Annonamuricata Linn) terhadap Bakteri Escherichia coli dan Staphylococcusaureus

    Pradikta, Rina

    2015-01-01

    Antibacterial activity of methanol extract soursop leaf (Annona muricata Linn) toEscherichia coli, and Staphylococcus aureus with diffusionmethod has been done. Result showed soursop leaf methanol extract (Annona muricata Linn) has activity as antibacterial. at concentration of 10 % to Escherichia coli and Staphylococcus aureus with resistancediameter of 10 mm to Escherichia coli, and 8,52 mm to Staphylococcus aureus each. While in the water solvent resistent diameter for bacteria Escherichia...

  6. Occurrence of pathogenic and faecal Escherichia coli in layer hens

    Silvia Tagliabue

    2010-01-01

    Full Text Available A total of 117 Escherichia coli from colibacillosis affected (APEC and clinically healthy birds (AFEC were serotyped and tested for the presence of virulence genes: iss, tsh, cva. A total of 54.5% E. Coli were typeable and 15 different serogroups were identified. The most common serogroups among APEC strains were O78, O2 and O128, whereas O139 was predominant in faecal strains from healthy birds. Iss, tsh e cva were more frequently detected among the septicaemic E. coli strains. The association of virulence genes was observed. Particularly, the pathotype iss-tsh-cva was present in 46.5% of APEC strains. Referring to serogroups, E. coli O78 and O2 originating from colibacillosis affected birds were always isstsh- cva positive but did not share virulence genes when they came from healthy birds.

  7. Alterations induced in Escherichia Coli cells by gamma radiation

    Modifications occurred in Escherichia coli cells exposed to gamma radiation (60Co source) were investigated. The irradiations were done at the LIN-COPPE laboratory of the UFRJ and the analysis at the Biology Department of the UTFPR. The E. coli cells were irradiated with 30, 60, 90, 120, 150, 180, 210, 240, 300, 480, 600 e 750 Gy doses. The samples were analyzed with Gram-stain, biochemical tests in EPM, MIO and Lysine Broth, Simmons Cytrate Medium and Rhamnose Broth, antibiogram and isolation of auxotrophic mutants. It was observed that for the received doses the E. coli did not show morphological alterations in the tests. Some E. Coli cells showed to be able to deaminade the L-tryptophan or they changed their sensibility for amoxillin and cephaloonine after the irradiation. The existence of aauxotrophic mutants after irradiation was also verified. (author)

  8. Peptide nucleic acid (PNA) antisense effects in Escherichia coli

    Good, L; Nielsen, P E

    1999-01-01

    Antisense peptide nucleic acid (PNA) can be used to control cell growth, gene expression and growth phenotypes in the bacteria Escherichia coli. PNAs targeted to the RNA components of the ribosome can inhibit translation and cell growth, and PNAs targeted to mRNA can limit gene expression with gene...... and sequence specificity. In an E. coli cell extract, efficient inhibition is observed when using PNA concentrations in the nanomolar range, whereas micromolar concentrations are required for inhibition in growing cells. A mutant strain of E. coli that is more permeable to antibiotics also is more...... susceptible to antisense PNAs than the wild type. This chapter details methods for testing the antisense activities of PNA in E. coli. As an example of the specific antisense inhibition possible, we show the effects of an anti-beta-galactosidase PNA in comparison to control PNAs. With improvements in cell...

  9. Escherichia coli as Host and Pathogen

    2013-01-01

    Enterohemorrhagic E. coli (EHEC) are highly infectious food-borne pathogens that cause severe diarrhoea in both, industrialised and developing countries all over the world. Their pathogenicity factors involve shiga-like toxins and a type III secretion system along with so called effector proteins, which are translocated directly into the cytoplasm of their host cells, usually enterocytes. Most of these proteins are encoded in pathogenicity islands within the bacterial genome that are framed b...

  10. Binding characteristics of Escherichia coli adhesins in human urinary bladder.

    Virkola, R; Westerlund, B; Holthöfer, H; Parkkinen, J; Kekomäki, M; Korhonen, T K

    1988-01-01

    We studied domains in the human bladder that acted as receptors for Escherichia coli P, S, type 1, type 1C, and O75X fimbriae or adhesin and domains in the human kidneys that were receptors for E. coli type 1C fimbriae. Binding sites in frozen tissue sections were localized by direct staining with fluorochrome-labeled recombinant strains and by indirect immunofluorescence with the purified adhesins. In the bladder, the P and S fimbriae showed closely similar binding to the epithelial and musc...

  11. DNA microarray analysis of fim mutations in Escherichia coli

    Schembri, Mark; Ussery, David; Workman, Christopher;

    2002-01-01

    Bacterial adhesion is often mediated by complex polymeric surface structures referred to as fimbriae. Type I fimbriae of Escherichia coli represent the archetypical and best characterised fimbrial system. These adhesive organelles mediate binding to D-mannose and are directly associated with...... we have used DNA microarray analysis to examine the molecular events involved in response to fimbrial gene expression in E. coli K-12. Observed differential expression levels of the fim genes were in good agreement with our current knowledge of the stoichiometry of type I fimbriae. Changes in fim...

  12. Novel Aggregative Adherence Fimbria Variant of Enteroaggregative Escherichia coli

    Jønsson, Rie; Struve, Carsten; Boisen, Nadia;

    2015-01-01

    Enteroaggregative Escherichia coli (EAEC) organisms belong to a diarrheagenic pathotype known to cause diarrhea and can be characterized by distinct aggregative adherence (AA) in a stacked-brick pattern to cultured epithelial cells. In this study, we investigated 118 EAEC strains isolated from the....... Transformation to a nonadherent E. coli HB101 and complementation of the nonadherent C338-14 mutant with the complete gene cluster restored the AA adhesion. Overall, we found the agg5A gene in 12% of the 118 strains isolated from Denmark, suggesting that this novel adhesin represents an important variant....

  13. Recombinant protein expression in Escherichia coli: advances and challenges

    GermánLeandroRosano

    2014-04-01

    Full Text Available Escherichia coli is the organism 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 recombinant 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.

  14. Antibacterial behavior of diamond nanoparticles against Escherichia coli

    Beranova, Jana; Seydlova, Gabriela [Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnicka 10, 16200 Prague (Czech Republic); Department of Genetics and Microbiology, Faculty of Science, Charles University in Prague, Vinicna 5, 12844 Prague (Czech Republic); Kozak, Halyna; Potocky, Stepan; Kromka, Alexander [Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnicka 10, 16200 Prague (Czech Republic); Konopasek, Ivo [Department of Genetics and Microbiology, Faculty of Science, Charles University in Prague, Vinicna 5, 12844 Prague (Czech Republic)

    2012-12-15

    In this study, we investigated the potential antibacterial properties of nanocrystalline diamond. In particular, we tested the effect of diamond nanoparticles (DNPs) on growth of the model gram-negative bacterium Escherichia coli on solid, nutrient-rich growth medium. We found that the presence of DNPs on agar plates significantly reduced the colony forming ability of E. coli. The antibacterial effect occurred in a concentration dependent manner and was conditional on the specific ratio of DNPs to the number of bacterial cells. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. Genetic determinants of heat resistance in Escherichia coli

    Ryan eMercer; Jinshui eZheng; Rigoberto eGarcia-Hernandez; Lifang eRuan; Michael eGänzle; Lynn eMcMullen

    2015-01-01

    Escherichia coli AW1.7 is a heat resistant food isolate and the occurrence of pathogenic strains with comparable heat resistance may pose a risk to food safety. To identify the genetic determinants of heat resistance, 29 strains of E. coli that differed in their of heat resistance were analyzed by comparative genomics. Strains were classified as highly heat resistant strains, exhibiting a D60-value of more than 6 min; moderately heat resistant strains, exhibiting a D60-value of more than 1 mi...

  16. FimH-mediated autoaggregation of Escherichia coli

    Schembri, Mark; Christiansen, G.; Klemm, Per

    2001-01-01

    Autoaggregation is a phenomenon thought to contribute to colonization of mammalian hosts by pathogenic bacteria. Type 1 fimbriae are surface organelles of Escherichia coli that mediate D-mannose-sensitive binding to various host surfaces. This binding is conferred by the minor fimbrial component...... FimH. In this study, we have used random mutagenesis to identify variants of the FimH adhesin that confer the ability of E. coli to autoaggregate and settle from liquid cultures. Three separate autoaggregating clones were identified, all of which contained multiple amino acid changes located within...

  17. Properties and biosynthesis of cyclopropane fatty acids in Escherichia coli.

    Cronan, J E; Reed, R; Taylor, F R; Jackson, M B

    1979-01-01

    The lipid phase transition of Escherichia coli phospholipids containing cyclopropane fatty acids was compared with the otherwise homologous phospholipids lacking cyclopropane fatty acids. The phase transitions (determined by scanning calorimetry) of the two preparations were essentially identical. Infection of E. coli with phage T3 inhibited cyclopropane fatty acid formation over 98%, whereas infection with mutants which lack the phage coded S-adenosylmethionine cleavage enzyme had no effect on cyclopropane fatty acid synthesis. These data indicate that S-adenosylmethionine is the methylene in cyclopropane fatty acid synthesis. PMID:374358

  18. Molecular basis of valine resistance in Escherichia coli K-12.

    Lawther, R P; Calhoun, D H; Adams, C W; Hauser, C A; Gray, J.; Hatfield, G W

    1981-01-01

    The relationship of valine resistance to the expression of the ilvGEDA operon of Escherichia coli K-12 has been determined. DNA sequence and in vivo protein analyses indicate that in wild-type E. coli K-12 there is a frameshift site within the gene (ilvG) for valine resistance. The ilvG+2096 (formerly designated ilv02096) mutation displaces this frameshift site, resulting in the expression of ilvG and the relief of transcriptional polarity on the distal genes of this operon. Thus, the "ilv0" ...

  19. Dexamethazone protects against Escherichia coli induced sickness behavior in rats.

    Hanaa-Mansour, A; Hassan, Wedad A; Georgy, Gehan S

    2016-01-01

    Systemic bacterial infection results in systemic inflammatory response syndrome due to the release of lipopolysaccharide (LPS) in blood that can lead to multiple organ failure, shock, and potentially death. Other impact, LPS exposure produces robust increase in anxiety-like behavior, suppression of locomotor, exploratory activity, and reduced social behavior. The therapeutic use of glucocorticoids in septic shock remains one of the first-aid approaches for their anti-inflammatory properties. The aim of this study was to evaluate the possible protective effect of dexamethazone (DEX), the most commonly used corticosteroid, against Escherichia coli (E. coli) immunohistochemical changes and neurobehavioral dysfunction. To this end, male Sprague-Dawley rats were divided into four groups; (1) Control group (2) E. coli infected group, where animals received 0.2 ml of 24 h growth of E. coli suspension in nutrient broth containing approximately 1.8×10(8) cfu/ml i.p for once, 48 h before sacrificing (3) DEX (20 mg/kg, i.p, 3 days) treated group (4) DEX and E. coli treated group. The results revealed that DEX significantly protected animals against most E. coli-induced behavioral deficits, reduced signs of cognitive impairment. DEX also reduced the LPS-evoked rise in C-reactive protein (CRP), Interferon gamma (IFγ), as well as, expression of Caspase-3. In conclusion, DEX provides neuroprotection against E. coli-associated neurobehavioral and immunological changes via its anti-inflammatory and immunomodulatory effects. PMID:26541583

  20. Mechanobiology of Antimicrobial Resistant Escherichia coli and Listeria innocua

    Tajkarimi, Mehrdad; Harrison, Scott H.; Hung, Albert M.; Graves, Joseph L.

    2016-01-01

    A majority of antibiotic-resistant bacterial infections in the United States are associated with biofilms. Nanoscale biophysical measures are increasingly revealing that adhesive and viscoelastic properties of bacteria play essential roles across multiple stages of biofilm development. Atomic Force Microscopy (AFM) applied to strains with variation in antimicrobial resistance enables new opportunities for investigating the function of adhesive forces (stickiness) in biofilm formation. AFM force spectroscopy analysis of a field strain of Listeria innocua and the strain Escherichia coli K-12 MG1655 revealed differing adhesive forces between antimicrobial resistant and nonresistant strains. Significant increases in stickiness were found at the nanonewton level for strains of Listeria innocua and Escherichia coli in association with benzalkonium chloride and silver nanoparticle resistance respectively. This advancement in the usage of AFM provides for a fast and reliable avenue for analyzing antimicrobial resistant cells and the molecular dynamics of biofilm formation as a protective mechanism. PMID:26914334

  1. Findings of Escherichia coli and Enterococcus spp. in homemade cheese

    Tambur Zoran; Opačić Dolores; Doder Radoje; Marković Miroslav

    2007-01-01

    During the period from February until March 2004, 108 samples of soft cheese originating from markets of Pancevo, Subotica and Belgrade were examined. Microbiological analyses of the cheese samples to the presence of Escherichia coli was performed using methods described in the Regulations on methods for performing microbiological analyses and super analyses of consumer articles, while the presence of bacteria Enteroccocus spp. was performed on the dexter agar. From 108 samples of soft cheese...

  2. Mechanistic aspects of thiamine biosynthesis in escherichia coli

    Challand, M.R

    2011-01-01

    The biosynthesis of the vitamin thiamine is laden with interesting chemistry. In anaerobic bacteria (such as Escherichia coli) a reactive intermediate, dehydroglycine, required for the biosynthesis of the thiazole moiety is derived from cleavage of the C??C? bond of tyrosine in a reaction catalysed by the radical S-adenosyl-L-methionine (SAM) enzyme, tyrosine lyase (ThiH). The aromatic by-product of this reaction in vivo was unequivocally characterised as p-cresol, a result which supported pr...

  3. Polynucleotide Phosphorylase Protects Escherichia coli against Oxidative Stress†

    Wu, Jinhua; Jiang, Zhe; Liu, Min; Gong, Xin; Wu, ShaoHui; Burns, Christopher M.; Li, Zhongwei

    2009-01-01

    Escherichia coli polynucleotide phosphorylase (PNPase) primarily functions in RNA degradation. It is an exoribonuclease and integral component of the multienzyme RNA degradosome complex [Carpousis et al. (1994) Cell 76, 889]. PNPase was previously shown to specifically bind a synthetic RNA containing the oxidative lesion 8-hydroxyguanine (8-oxoG) [Hayakawa et al. (2001) Biochemistry 40, 9977], suggesting a possible role in removing oxidatively damaged RNA. Here we show that PNPase binds to RN...

  4. Chromosome partition in Escherichia coli requires postreplication protein synthesis.

    Donachie, W. D.; Begg, K J

    1989-01-01

    After inhibition of protein synthesis, the number of nuclear bodies (nucleoids) visible in cells of Escherichia coli B/rA corresponded closely to the number of completely replicated chromosomes. We calculated that nucleoid partition follows almost immediately after replication forks reach the chromosome terminus. We show that such a partition is dependent on protein synthesis and that this may reflect the requirement that cells must achieve a certain minimum length before partition (and subse...

  5. Occurrence of Escherichia coli in Wild Cottontail Rabbits.

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

    1977-03-01

    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

  6. Identification of Uropathogenic Escherichia coli Surface Proteins by Shotgun Proteomics

    Walters, Matthew S.; Mobley, Harry L. T.

    2009-01-01

    Uropathogenic Escherichia coli (UPEC) cause the majority of uncomplicated urinary tract infections in humans. In the process of identifying candidate antigens for a vaccine, two methods for the identification of the UPEC surface proteome during growth in human urine were investigated. The first approach utilized a protease to ‘shave’ surface-exposed peptides from the bacterial cell surface and identify them by mass spectrometry. Although this approach has been successfully applied to a Gram-p...

  7. Expression of a proline-enriched protein in Escherichia coli.

    Kangas, T T; Cooney, C L; Gomez, R F

    1982-01-01

    The feasibility of expressing repeated synthetic codons in bacterial cells was demonstrated by showing that repeated codons for proline were expressed in Escherichia coli. Recombinant DNA technology was used to clone synthetic polydeoxyguanylate:polydeoxycytidylate into the PstI site of plasmid pBR322. Recombinant plasmid pGC139 was shown by means of HaeIII restriction digestion to contain approximately 41 cloned base pairs; the cloned sequence was expressed as a fusion to an ampicillinase pr...

  8. Genetic Analysis of the Maltose A Region in Escherichia coli

    Hatfield, Dolph; Hofnung, Maurice; Schwartz, Maxime

    1969-01-01

    The genetic map of the maltose A locus of Escherichia coli contains at least three closely linked genes, malT, malP, and malQ. The order of these genes is established by deletion mapping. MalP and malQ, the presumed structural genes for maltodextrin phosphorylase and amylomaltase, belong to the same operon. MalT may be a regulator gene involved in the positive control of this operon. PMID:4891257

  9. 2DBase: 2D-PAGE database of Escherichia coli

    Vijayendran, Chandran; Burgemeister, Sebastian; Friehs, Karl; Niehaus, Karsten; Flaschel, Erwin

    2007-01-01

    We present a web-based integrated proteome database, termed 2DBase of Escherichia coli which was designed to store, compare, analyse, and retrieve various information obtained by 2D polyacrylamide gel electrophoresis and mass spectrometry. The main objectives of this database are (1) to provide the features for query and data-mining applications to access the stored proteomics data (2) to efficiently compare the specific protein spots present in the comparable proteome maps and (3) to analyse...

  10. Quinolone accumulation in Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus.

    McCaffrey, C; Bertasso, A; Pace, J.; Georgopapadakou, N H

    1992-01-01

    The accumulation of quinolones by Escherichia coli JF568, Pseudomonas aeruginosa PAO1, and Staphylococcus aureus ATCC 29213 was measured by a modified fluorometric assay (J. S. Chapman and N. H. Georgopapadakou, Antimicrob. Agents Chemother. 33:27-29, 1989). The quinolones examined were fleroxacin, pefloxacin, norfloxacin, difloxacin, A56620, ciprofloxacin, ofloxacin, and Ro 09-1168. In all three organisms, uptake was complete in less than 5 min and was proportional to extracellular quinolone...

  11. Metabolic engineering of Escherichia coli for the production of cinnamaldehyde

    Bang, Hyun Bae; Lee, Yoon Hyeok; Kim, Sun Chang; Sung, Chang Keun; Jeong, Ki Jun

    2016-01-01

    Background Plant parasitic nematodes are harmful to agricultural crops and plants, and may cause severe yield losses. Cinnamaldehyde, a volatile, yellow liquid commonly used as a flavoring or food additive, is increasingly becoming a popular natural nematicide because of its high nematicidal activity and, there is a high demand for the development of a biological platform to produce cinnamaldehyde. Results We engineered Escherichia coli as an eco-friendly biological platform for the productio...

  12. Structural systems biology evaluation of metabolic thermotolerance in Escherichia coli

    Chang, Roger L.; Andrews, Kathleen; Kim, Donghyuk; Li, Zhanwen; Godzik, Adam; Palsson, Bernhard Ø.

    2013-01-01

    Genome scale network reconstruction has enabled predictive modeling of metabolism for many systems. Traditionally, protein structural information has not been represented in such reconstructions. Expanding a genome-scale model of Escherichia coli metabolism by including experimental and predicted protein structures enabled the analysis of protein thermostability in a network context, allowing prediction of protein activities that limit network function at super-optimal temperature and mechani...

  13. Pet, an Autotransporter Enterotoxin from Enteroaggregative Escherichia coli

    Eslava, Carlos; Navarro-García, Fernando; Czeczulin, John R.; Henderson, Ian R.; Cravioto, Alejandro; James P. Nataro

    1998-01-01

    Enteroaggregative Escherichia coli (EAEC) is an emerging cause of diarrheal illness. Clinical data suggest that diarrhea caused by EAEC is predominantly secretory in nature, but the responsible enterotoxin has not been described. Work from our laboratories has implicated a ca. 108-kDa protein as a heat-labile enterotoxin and cytotoxin, as evidenced by rises in short-circuit current and falls in tissue resistance in rat jejunal tissue mounted in an Ussing chamber. Here we report the genetic cl...

  14. The stringent response and cell cycle arrest in Escherichia coli.

    Daniel J Ferullo; Lovett, Susan T.

    2008-01-01

    The bacterial stringent response, triggered by nutritional deprivation, causes an accumulation of the signaling nucleotides pppGpp and ppGpp. We characterize the replication arrest that occurs during the stringent response in Escherichia coli. Wild type cells undergo a RelA-dependent arrest after treatment with serine hydroxamate to contain an integer number of chromosomes and a replication origin-to-terminus ratio of 1. The growth rate prior to starvation determines the number of chromosomes...

  15. The Stringent Response and Cell Cycle Arrest in Escherichia coli

    Daniel J Ferullo; Lovett, Susan T.

    2008-01-01

    The bacterial stringent response, triggered by nutritional deprivation, causes an accumulation of the signaling nucleotides pppGpp and ppGpp. We characterize the replication arrest that occurs during the stringent response in Escherichia coli. Wild type cells undergo a RelA-dependent arrest after treatment with serine hydroxamate to contain an integer number of chromosomes and a replication origin-to-terminus ratio of 1. The growth rate prior to starvation determines the number of chromosomes...

  16. Conjugative plasmid transfer from Enterococcus faecalis to Escherichia coli.

    Trieu-Cuot, P; Carlier, C; Courvalin, P

    1988-01-01

    The possibility of transfer of genetic information by conjugation from gram-positive to gram-negative bacteria was investigated with a pBR322-pAM beta 1 chimeric plasmid, designated pAT191. This shuttle vector, which possesses the tra functions of the streptococcal plasmid pAM beta 1, was conjugatively transferred from Enterococcus faecalis to Escherichia coli with an average frequency of 5 x 10(-9) per donor colony formed after mating.

  17. Widespread antibiotic resistance of diarrheagenic Escherichia coli and Shigella species

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

    2014-01-01

    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 iso...

  18. Functional expression of mouse mdr1 in Escherichia coli.

    Bibi, E; Gros, P.; Kaback, H R

    1993-01-01

    We describe functional expression of the mouse multidrug-resistance protein (P-glycoprotein; P-gp) in an Escherichia coli mutant defective in the outer membrane protease ompT. Heterologously expressed mdr1 appears as an unglycosylated species with an apparent molecular mass of 140 kDa in the membrane of the mutant. Unglycosylated mdr1 retains the ability to bind the photoactivatable drug analog [125I]iodoarylazidoprazosin and confers resistance to tetraphenylphosphonium (TPP+) and tetraphenyl...

  19. CRISPR-Cas Functional Module Exchange in Escherichia coli

    Almendros, Cristóbal; Mojica, Francisco J. M.; Díez-Villaseñor, César; Guzmán, Noemí M.; García-Martínez, Jesús

    2014-01-01

    Clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated (cas) genes constitute the CRISPR-Cas systems found in the Bacteria and Archaea domains. At least in some strains they provide an efficient barrier against transmissible genetic elements such as plasmids and viruses. Two CRISPR-Cas systems have been identified in Escherichia coli, pertaining to subtypes I-E (cas-E genes) and I-F (cas-F genes), respectively. In order to unveil the evolutionary dynamics of ...

  20. Vaccinia DNA topoisomerase I promotes illegitimate recombination in Escherichia coli.

    Shuman, S

    1989-01-01

    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. Express...

  1. Spurious hydrogen sulfide production by Providencia and Escherichia coli species.

    Treleaven, B E; Diallo, A. A.; Renshaw, E C

    1980-01-01

    Hydrogen sulfide production was noted in two Escherichia coli strands and one Provaidenica alcalifaciens (Proteus inconstans A) strain isolated from clinical stool specimens durin the summer of 1979. An investigation into this phenomenon revealed the predence of Eubacterium lentum, an anaerobe, growing in synergism with the Enterobacteriaceae and producing H2s. The implications of this association are discssed with reference to clinical microbiology laboratory practice.

  2. Clonal relationships among bloodstream isolates of Escherichia coli.

    Maslow, J.N.; Whittam, T S; Gilks, C F; Wilson, R A; Mulligan, M E; Adams, K S; Arbeit, R D

    1995-01-01

    The clonal relationships among 187 bloodstream isolates of Escherichia coli from 179 patients at Boston, Mass., Long Beach, Calif., and Nairobi, Kenya, were determined by multilocus enzyme electrophoresis (MLEE), analysis of polymorphisms associated with the ribosomal operon (ribotyping), and serotyping. MLEE based on 20 enzymes resolved 101 electrophoretic types (ETs), forming five clusters; ribotyping resolved 56 distinct patterns concordant with the analysis by MLEE. The isolates at each s...

  3. Pathogenomics of the Virulence Plasmids of Escherichia coli

    Johnson, Timothy J.; Lisa K. Nolan

    2009-01-01

    Summary: Bacterial plasmids are self-replicating, extrachromosomal elements that are key agents of change in microbial populations. They promote the dissemination of a variety of traits, including virulence, enhanced fitness, resistance to antimicrobial agents, and metabolism of rare substances. Escherichia coli, perhaps the most studied of microorganisms, has been found to possess a variety of plasmid types. Included among these are plasmids associated with virulence. Several types of E. col...

  4. Genome-Scale Thermodynamic Analysis of Escherichia coli Metabolism

    Christopher S Henry; Jankowski, Matthew D.; Broadbelt, Linda J.; Hatzimanikatis, Vassily

    2005-01-01

    Genome-scale metabolic models are an invaluable tool for analyzing metabolic systems as they provide a more complete picture of the processes of metabolism. We have constructed a genome-scale metabolic model of Escherichia coli based on the iJR904 model developed by the Palsson Laboratory at the University of California at San Diego. Group contribution methods were utilized to estimate the standard Gibbs free energy change of every reaction in the constructed model. Reactions in the model wer...

  5. Escherichia coli and virus isolated from ''sticky kits''

    Jørgensen, M.; Scheutz, F.; Strandbygaard, Bertel

    1996-01-01

    A total of 121 Escherichia coli strains isolated from 3-week-old mink kits were serotyped and examined for virulence factors. 56 strains were isolated from healthy kits while 65 were from ''sticky kits''. Among these, 34 different serotypes were detected. No difference in serotypes or the presence...... of virulence factors could be detected between healthy and diseased kits. By electron microscopy of faecal samples corona-, rota-, and calicivirus were demonstrated among healthy as well as diseased kits....

  6. Analysis of resynthesis tracts in repaired Escherichia coli deoxyribonucleic acid.

    Kuemmerle, N; R. Ley; Masker, W

    1981-01-01

    Excision repair of ultraviolet radiation-induced damage in a wild-type strain of Escherichia coli has been examined, using two methods for characterizing the resynthesis step of the repair process. Comparison of data obtained after both isopycnic analysis of repaired deoxyribonucleic acid and sedimentation velocity analysis of deoxyribonucleic acid after selective photolysis of bromouracil-containing repaired regions has shown that the repaired deoxyribonucleic acid molecules contain a semico...

  7. relA Enhances the Adherence of Enteropathogenic Escherichia coli

    Beny Spira; Gerson Moura Ferreira; Luiz Gustavo de Almeida

    2014-01-01

    Enteropathogenic Escherichia coli (EPEC) is a known causative agent of diarrhea in children. In the process of colonization of the small intestine, EPEC synthesizes two types of adhesins, the bundle-forming pilus (BFP) and intimin. The BFP pilus is an adhesin associated with the initial stages of adherence of EPEC to epithelial cells, while the outer membrane protein intimin carries out the intimate adherence that takes place at the third stage of infection. BFP is encoded by the bfp operon l...

  8. Induction and control of the autolytic system of Escherichia coli.

    Leduc, M.; Kasra, R; van Heijenoort, J

    1982-01-01

    Various methods of inducing autolysis of Escherichia coli cells were investigated, some being described here for the first time. For the autolysis of growing cells only induction methods interfering with the biosynthesis of peptidoglycan were taken into consideration, whereas with harvested cells autolysis was induced by rapid osmotic or EDTA shock treatments. The highest rates of autolysis were observed after induction by moenomycin, EDTA, or cephaloridine. The different autolyses examined s...

  9. Mobilization of Thiobacillus ferrooxidans plasmids among Escherichia coli strains.

    Rawlings, D. E.; Woods, D R

    1985-01-01

    Nonconjugative Thiobacillus ferrooxidans plasmids were mobilized at high frequencies among Escherichia coli strains by the IncP plasmid RP4 and at low frequencies by the IncN plasmid R46, but not by the IncW plasmid pSa. The mobilization region of a nonconjugative T. ferrooxidans plasmid was located on a 5.3-kilobase T. ferrooxidans DNA fragment.

  10. Biomolecular Mechanisms of Pseudomonas aeruginosa and Escherichia coli Biofilm Formation

    Garry Laverty

    2014-07-01

    Full Text Available 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.

  11. The asymptomatic bacteriuria Escherichia coli strain 83972 outcompetes uropathogenic E. coli strains in human urine

    Hancock, Viktoria; Ulett, G.C.; Schembri, M.A.;

    2006-01-01

    Escherichia coli is the most common organism associated with asymptomatic bacteriuria (ABU). In contrast to uropathogenic E. coli (UPEC), which causes symptomatic urinary tract infections (UTI), very little is known about the mechanisms by which these strains colonize the human urinary tract. The...... prototype ABU E. coli strain 83972 was originally isolated from a girl who had carried it asymptomatically for 3 years. Deliberate colonization of UTI-susceptible individuals with E. coli 83972 has been used successfully as an alternative approach for the treatment of patients who are refractory to...... conventional therapy. Colonization with strain 83972 appears to prevent infection with UPEC strains in such patients despite the fact that this strain is unable to express the primary adhesins involved in UTI, viz. P and type 1 fimbriae. Here we investigated the growth characteristics of E. coli 83972 in human...

  12. Escherichia coli. A sanitary methodology for faecal water pollution tests; Escherichia coli nelle acque. Significato sanitario e metodologie di analisi

    Bonadonna, L. [Istituto Superiore di Sanita' , Rome (Italy)

    2001-02-01

    Among the traditional indictors of faecal water pollution, Escherichia coli has shown to fit better with the definition of indicator organism. Till now its recovery has been time-consuming and needs confirmation tests. In this report more rapid and direct methods, based on enzymatic reactions, are presented. [Italian] Per talune peculiari caratteristiche, Escherichia coli sembra meglio soddisfare i requisiti insiti nella definizione di organismo indicatore, rispetto ai tradizionali indicatori di contaminazione fecale dell'acqua. Finora, i substrati disponibili per il suo rilevamento necessitano tutti di almeno una prova di conferma. Di qui l'esigenza di indicare metodi di rilevamento a riposta piu' rapida, anche in relazione all'inserimento, nelle piu' recenti normative nazionali ed europee, del microrganismo tra i parametri microbiologici da ricercare.

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

    Qureshi, Zubair A; Doi, Yohei

    2014-05-01

    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

  14. A stochastic killing system for biological containment of Escherichia coli

    Klemm, P.; Jensen, Lars Bogø; Molin, Søren

    1995-01-01

    Bacteria with a stochastic conditional lethal containment system have been constructed. The invertible switch promoter located upstream of the fimA gene from Escherichia coli was inserted as expression cassette in front of the Lethal gef gene deleted of its own natural promoter. The resulting...... fusion was placed on a plasmid and transformed to E. coli. The phenotype connected with the presence of such a plasmid was to reduce the population growth rate with increasing significance as the cell growth rate was reduced. In very fast growing cells, there was no measurable effect on growth rate. When...... a culture of E. coli harboring the plasmid comprising the containment system is left as stationary cells in suspension without nutrients, viability drops exponentially over a period of several days, in contrast to the control cells, which maintain viability nearly unaffected during the same period...

  15. The Escherichia coli transcriptome linked to growth fitness

    Bei-Wen Ying

    2016-03-01

    Full Text Available A series of Escherichia coli strains with varied genomic sequences were subjected to high-density microarray analyses to elucidate the fitness-correlated transcriptomes. Fitness, which is commonly evaluated by the growth rate during the exponential phase, is not only determined by the genome but is also linked to growth conditions, e.g., temperature. We previously reported genetic and environmental contributions to E. coli transcriptomes and evolutionary transcriptome changes in thermal adaptation. Here, we describe experimental details on how to prepare microarray samples that truly represent the growth fitness of the E. coli cells. A step-by-step record of sample preparation procedures that correspond to growing cells and transcriptome data sets that are deposited at the GEO database (GSE33212, GSE52770, GSE61739 are also provided for reference.

  16. Impact of antibiotic restriction on resistance levels of Escherichia coli

    Boel, Jonas; Andreasen, Viggo; Jarløv, Jens Otto;

    2016-01-01

    OBJECTIVES: We evaluated the effect of an antibiotic stewardship programme (ASP) on the use of antibiotics and resistance levels of Escherichia coli using a method that allowed direct comparison between an intervention hospital and a control hospital. METHODS: The study was conducted as a...... of E. coli. Results were directly compared with data from the control hospital utilizing a subtracted time series (STS). RESULTS: Direct comparison with the control hospital showed that the ASP was associated with a significant change in the level of use of cephalosporins [-151 DDDs/1000 bed-days (95......% CI -177, -126)] and fluoroquinolones [-44.5 DDDs/1000 bed-days (95% CI -58.9, -30.1)]. Resistance of E. coli showed a significant change in slope for cefuroxime [-0.13 percentage points/month (95% CI -0.21, -0.057)] and ciprofloxacin [-0.15 percentage points/month (95% CI -0.26, -0.038)]. CONCLUSIONS...

  17. Novel roles for the AIDA adhesin from diarrheagenic Escherichia coli:

    Sherlock, Orla; Schembri, Mark; Reisner, A.;

    2004-01-01

    Diarrhea-causing Escherichia coli strains are responsible for numerous cases of gastrointestinal disease and constitute a serious health problem throughout the world. The ability to recognize and attach to host intestinal surfaces is an essential step in the pathogenesis of such strains. AIDA is a...... potent bacterial adhesin associated with some diarrheagenic E. coli strains. AIDA mediates bacterial attachment to a broad variety of human and other mammalian cells. It is a surface-displayed autotransporter protein and belongs to the selected group of bacterial glycoproteins; only the glycosylated form...... binds to mammalian cells. Here, we show that AIDA possesses self-association characteristics and can mediate autoaggregation of E. coli cells. We demonstrate that intercellular AIDA-AIDA interaction is responsible for bacterial autoaggregation. Interestingly, AIDA-expressing cells can interact with...

  18. Escherichia coli portador de betalactamasas de espectro extendido: resistencia

    Mª C. Miranda García

    2013-12-01

    Full Text Available Introducción: Escherichia coli es el microorganismo que con más frecuencia se encuentra implicado en infecciones nosocomiales y comunitarias, patógeno responsable en la etiología de infecciones de vías respiratorias altas, infecciones del tracto urinario, heridas quirúrgicas, sangre o gastroenteritis. En los últimos años ha experimentado importantes cambios encontrándose un aumento de infecciones por cepas de éstos microorganismos productores de betalactamasas de espectro extendido. Objetivos: Se decide hacer este estudio retrospectivo de las muestras procesadas en el Laboratorio de Microbiología del Hospital Básico de la Defensa San Carlos (San Fernando, para conocer la frecuencia y el patrón de sensibilidad en nuestra población por gérmenes productores de betalactamasas de espectro extendido en este caso por Escherichia coli, dada la importancia de las infecciones causadas por esta bacteria y la repercusión que tiene por todo el mundo los mecanismos de resistencia. Material y Método: Se recogieron los datos de resultados obtenidos en las muestras procesadas en el Laboratorio de Microbiología durante 36 meses (Enero 2009 a Diciembre 2011, en las que se hubieran identificado cepas de Escherichia coli y de éstas las productoras de betalactamasas de espectro extendido. Resultados: Se aislaron 34 cepas de Escherichia coli productoras de betalactamasas de espectro extendido lo que supone una tasa del 5,10%. Se encontró una frecuencia mayor en el año 2010 (6,9% que en el 2009 (2,61%, pero similar al 2011 (5,98%. Conclusión: La frecuencia de cepas Escherichia coli con betalactamasas de espectro extendido encontrada es similar a la de otros estudios realizados en España, pero la tasa de resistencia de algunos antimicrobianos como Amoxicilina/clavulánico, Cotrimoxazol y Fluorquinolonas en nuestra población es elevada.

  19. Effect of tannins on the in viro growth of Escherichia coli O157:H7 and in vivo growth of generic Escherichia coli excreted from steers

    The effect of commercially available chestnut and mimosa tannins in vitro (experiment 1) or in vivo (experiment 2) on the growth or recovery of Escherichia coli O157:H7 or generic fecal E. coli was evaluated. In experiment 1, the mean growth rate of E. coli O157:H7, determined via the measurement o...

  20. Effective medicinal plants against enterohaemorrhagic Escherichia coli O157:H7.

    Voravuthikunchai, Supayang; Lortheeranuwat, Amornrat; Jeeju, Wanpen; Sririrak, Trechada; Phongpaichit, Souwalak; Supawita, Thanomjit

    2004-09-01

    The stimulating effect of subinhibitory concentrations of antibiotics on the production of verocytotoxin (VT) by enterohaemorrhagic Escherichia coli (EHEC) O157:H7 has been claimed. The purpose of this study was to find an alternative, but bioactive medicine for the treatment of this organism. Fifty-eight preparations of aqueous and ethanolic extracts of 38 medicinal plant species commonly used in Thailand to cure gastrointestinal infections were tested for their antibacterial activity against different strains of Escherichia coli, including 6 strains of Escherichia coli O157:H7, Escherichia coli O26:H11, Escherichia coli O111:NM, Escherichia coli O22; 5 strains of Escherichia coli isolated from bovine; and Escherichia coli ATCC 25922. Inhibition of growth was primarily tested by the paper disc agar diffusion method. Among the medicinal plants tested, only 8 species (21.05%) exhibited antimicrobial activity against Escherichia coli O157:H7. Acacia catechu, Holarrhena antidysenterica, Peltophorum pterocarpum, Psidium guajava, Punica granatum, Quercus infectoria, Uncaria gambir, and Walsura robusta demonstrated antibacterial activity with inhibition zones ranging from 7 to 17 mm. The greatest inhibition zone against Escherichia coli O157:H7 (RIMD 05091083) was produced from the ethanolic extract of Quercus infectoria. Minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) were determined by the agar microdilution method and agar dilution method in petri dishes with millipore filter. Both aqueous and ethanolic extracts of Quercus infectoria and aqueous extract of Punica granatum were highly effective against Escherichia coli O157:H7 with the best MIC and MBC values of 0.09, 0.78, and 0.19, 0.39 mg/ml, respectively. These plant species may provide alternative but bioactive medicines for the treatment of Escherichia coli O157:H7 infection. PMID:15261962

  1. Cloning and expression of secreted antigens of Clostridium difficile in Escherichia coli.

    Dailey, D C; Schloemer, R H

    1988-01-01

    The feasibility of the cloning and expression of Clostridium difficile antigens in Escherichia coli was investigated. The expression of a limited number of cloned clostridial antigens under the control of clostridial promoter elements in E. coli was observed.

  2. Role of peripheral pooling in porcine Escherichia coli sepsis

    In anesthesized pigs the effects of E. coli (2 X 10(8)/kg) on hemodynamics and red cell distribution were studied. After injection of 99m-Tc red cells (15 mCi), regional radioactivity was followed during 3 hours. Gated bloodpool studies were performed to measure end-diastolic volumes (EDV). Escherichia coli E. coli was infused in 14 pigs, while 7 animals served as controls. E. coli resulted in an early increase in pulmonary arterial pressure. Systemic arterial pressure decreased gradually, while cardiac output did not change significantly. The gated studies revealed that especially left ventricular end-diastolic volume (LVEDV) declined, to 50% of the basal value. Regional radioactivity did not change over lungs, liver and abdomen. Splenic activity declined markedly. Over the hindlimb a significant increase (29 +/- 8%) was observed. It is concluded that E. coli infusion in pigs induces a hemodynamic pattern similar to human sepsis. The decrease in LVEDV is probably related to peripheral pooling and a change in right ventricle (RV) performance

  3. Phylogenetic analysis of Escherichia coli strains isolated from human samples

    Abdollah Derakhshandeh

    2013-12-01

    Full Text Available Escherichia coli (E. coli is a normal inhabitant of the gastrointestinal tract of vertebrates, including humans. Phylogenetic analysis has shown that E. coli is composed of four main phylogenetic groups (A, B1, B2 and D. Group A and B1 are generally associated with commensals, whereas group B2 is associated with extra-intestinal pathotypes. Most enteropathogenic isolates, however, are assigned to group D. In the present study, a total of 102 E. coli strains, isolated from human samples, were used. Phylogenetic grouping was done based on the Clermont triplex PCR method using primers targeted at three genetic markers, chuA, yjaA and TspE4.C2. Group A contained the majority of the collected isolates (69 isolates, 67.64%, followed by group B2 (18 isolates, 17.64% and D (15 isolates, 14.7% and no strains were found to belong to group B1. The distribution of phylogenetic groups in our study suggests that although the majority of strains were commensals, the prevalence of enteropathogenic and extra-intestinal pathotypes was noteworthy. Therefore, the role of E. coli in human infections including diarrhea, urinary tract infections and meningitis should be considered.

  4. Selective detection of Escherichia coli DNA using fluorescent carbon spindles.

    Roy, Anurag; Chatterjee, Sabyasachi; Pramanik, Srikrishna; Devi, Parukuttyamma Sujatha; Suresh Kumar, Gopinatha

    2016-04-28

    We investigate the interaction of hydrophilic blue emitting carbon spindles with various deoxyribonucleic acids (DNA) having different base pair compositions, such as Herring testes (HT), calf thymus (CT), Escherichia coli (EC) and Micrococcus lysodeikticus (ML) DNA, to understand the mode of interaction. Interestingly, the fluorescent carbon spindles selectively interacted with E. coli DNA resulting in enhanced fluorescence of the former. Interaction of the same carbon with other DNAs exhibited insignificant changes in fluorescence. In addition, in the presence of EC DNA, the D band in the Raman spectrum attributed to the defect state completely disappeared, resulting in enhanced crystallinity. Microscopy images confirmed the wrapping of DNA on the carbon spindles leading to the assembly of spindles in the form of flowers. Dissociation of double-stranded DNA occurred upon interaction with carbon spindles, resulting in selective E. coli DNA interaction. The carbon spindles also exhibited a similar fluorescence enhancement upon treating with E. coli bacteria. These results confirm the possibility of E. coli detection in water and other liquid foods using such fluorescent carbon. PMID:27081680

  5. Escherichia coli B lacks one of the two initiator tRNA species present in E. coli K-12.

    Mandal, N; RajBhandary, U L

    1992-01-01

    We show that the metY locus which specifies tRNA(2fMet) in Escherichia coli K-12 specifies tRNA(1fMet) in E. coli B. This conclusion is based on results of Southern blot analysis of E. coli B and K-12 DNAs and on polymerase chain reaction amplification, cloning, and sequencing of an approximately 200-bp region of DNA corresponding to the metY loci of E. coli B and E. coli K-12. We also show that the metY locus of E. coli B is transcriptionally active. E. coli strains transformed with the mult...

  6. Characterization of Escherichia coli Strains from Cases of Childhood Diarrhea in Provincial Southwestern Nigeria

    Iruka N Okeke; Lamikanra, Adebayo; Steinrück, Hartmut; Kaper, James B.

    2000-01-01

    In a study carried out in small-town and rural primary health care centers in southwestern Nigeria, 330 Escherichia coli strains isolated from 187 children with diarrhea and 144 apparently healthy controls were examined for virulence traits. Based on the results of colony blot hybridization, strains were categorized as enteropathogenic E. coli (1.8%), enterotoxigenic E. coli (2.4%), enteroinvasive E. coli (1.2%), enterohemorrhagic E. coli (0.6%), enteroaggregative E. coli (10.3%), diffusely a...

  7. Viabilidad de Escherichia coli en presencia de diferentes contaminantes

    Antonio Rivera T

    2006-04-01

    Full Text Available La contaminación en ríos condiciona la presencia de microorganismos adaptados al ecosistema entre ellos a patógenos de importancia en salud pública. Objetivo: Determinar la viabilidad de Escherichia coli en presencia de nitrato de plata, carbonato de amonio, fenol y formaldehído. Materiales y métodos: Se tomaron muestras de agua del río Alseseca, que luego se sembró en medios de cultivo selectivos para enterobacterias, seleccionándose las colonias del género Escherichia, las cuales fueron sembradas en el medio de orientación CHROMagar ECC. Las muestras de E. coli se evaluaron en presencia de nitrato de plata, carbonato de amonio, fenol y formaldehído. Resultados: El grupo experimental presentó viabilidad en presencia de los cuatro compuestos, el grupo control positivo presentó nula viabilidad, la comparación entre los grupos mostró diferencia significativa (p< 0,05. Conclusión: Los aislamientos de E. coli mostraron viabilidad, implicando riesgos para el ecosistemas y la salud, ya que el río Alseseca atraviesa por el municipio de Puebla donde existen núcleos poblacionales importantes.

  8. Inactivation of Escherichia coli in soil by solarization

    Contamination of agricultural soil by fecal pathogenic bacteria poses a potential risk of infection to humans. For the biosafety control of field soil, soil solarization in an upland field was examined to determine the efficiency of solarization on the inactivation of Escherichia coli inoculated into soil as a model microorganism for human pathogenic bacteria. Soil solarization, carried out by sprinkling water and covering the soil surface with thin plastic sheets, greatly increased the soil temperature. The daily average temperature of the solarized soil was 4–10°C higher than that of the non-solarized soil and fluctuated between 31 and 38°C. The daily highest temperature reached more than 40°C for 8 days in total in the solarized soil during the second and third weeks of the experiment. Escherichia coli in the solarized soil became undetectable (< 0.08 c.f.u. g−1 dry soil) within 4 weeks as a result, whereas E. coli survived for more than 6 weeks in the non-solarized soil. Soil solarization, however, had little influence on the total direct count and total viable count of bacteria in the soil. These results indicate that soil solarization would be useful for the biosafety control of soil contaminated by human pathogens via immature compost or animal feces. (author)

  9. Overexpression and export of Vibrio anguillarum metalloprotease in Escherichia coli

    Zhang Fengli; Chi Zhenming; Chen Jixiang; Wu Longfei; Liang Likun

    2007-01-01

    Vibrio anguillarum metalloprotease, an extracellular zinc metalloprotease involved in the virulence mechanism of Vibrio anguillarum, is synthesized from the empA gene as a 611-residue precursor and naturally secreted via Sec secretion pathway in Vibrio anguillarum. In this study, heterologous expression of the empA gene encoding metallopmtease and export of the recombinant metalloprotease in Escherichia coliwere examined. The empA gene was subcloned into pBAD24 with arabinose promoter and sequenced. The sequence encoded a polypeptide(611 amino acids)consisting of four domains: a signal peptide, an Nterminal propeptide, a mature region and a C-terminal propeptide. The empA gene inserted in plasmid pBAD24 was overexpressed in TOP10 strain of E. Coli after arabinose induction. The 36kDa polypeptide of the recombinant metalloprotease as the mature protease was further confirmed by SDS-PAGE and immunoblotting. It was found that recombinant metalloprotease with the EmpA activity and antigenicity wasexported into the periplasm of Escherichia coli cells via Sec translocation pathway, whereas it was secreted into extracellular environments in V. Anguillarum. The results imply that the expression, export and processing mechanism of the protein in E. Coli are similar to those in V. Anguillarum.

  10. Widespread antibiotic resistance of diarrheagenic Escherichia coli and Shigella species

    Azam Fatahi Sadeghabadi

    2014-01-01

    Full Text Available 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.

  11. Toxicity mechanism of carbon nanotubes on Escherichia coli

    Young, Yu-Fu [Department of Materials Science and Engineering, National Tsing-Hua University, No. 101, Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan (China); Lee, Hui-Ju [Department of Life Science, National Tsing-Hua University, No. 101, Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan (China); Shen, Yi-Shan; Tseng, Shih-Hao; Lee, Chi-Young [Department of Materials Science and Engineering, National Tsing-Hua University, No. 101, Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan (China); Tai, Nyan-Hwa, E-mail: nhtai@mx.nthu.edu.tw [Department of Materials Science and Engineering, National Tsing-Hua University, No. 101, Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan (China); Chang, Hwan-You, E-mail: hychang@mx.nthu.edu.tw [Department of Life Science, National Tsing-Hua University, No. 101, Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan (China)

    2012-05-15

    Highlights: Black-Right-Pointing-Pointer F-MWCNTs possess higher antibiotic performance than that of the F-SWCNTs. Black-Right-Pointing-Pointer E. coli cells were pierced when incubated with F-MWCNTs and trapped when incubated with F-SWCNTs. Black-Right-Pointing-Pointer The rigidity and moment of CNTs play important role on the antibiotic effect. - Abstract: The influences of carbon nanomaterials on bacteria were investigated using three types of dispersed and functionalized carbon nanomaterials (F-CNMs), viz. functionalized carbon nanopowder (F-CNP), functionalized single-walled carbon nanotubes (F-SWCNTs), and functionalized multi-walled carbon nanotubes (F-MWCNTs). F-CNMs with different aspect ratios were used to study the influence of material configuration on the viability of Escherichia coli (E. coli). Although these materials were functionalized to improve their dispersibility, the original morphologies and chemical properties of the materials were maintained. Traditional bacteria quantitative plating analysis was conducted, and the results of which revealed that the F-CNP and the F-SWCNTs showed a less significant effect on the viability of E. coli, while the F-MWCNTs obviously inhibited cell viability. A Fourier transform infrared spectroscopy and a scanning electron microscopy were used to verify the functionalization of the F-CNMs and to examine the interaction of F-CNMs with E. coli, respectively; in addition, we adopted chemiluminescence assays to measure the concentration of adenosine triphosphate (ATP) released from the damaged cells. The results showed that the ATP of the F-MWCNTs sample is two-fold higher than that of the control, indicating direct piercing of E. coli by F-MWCNTs leads to bacteria death. Furthermore, F-SWCNTs were concluded to have less influence on the viability of E. coli because ultra-long F-SWCNTs used in this study performed less rigidity to pierce the cells.

  12. Multiplex PCR for Diagnosis of Enteric Infections Associated with Diarrheagenic Escherichia coli

    Vidal, Roberto; Vidal, Maricel; Lagos, Rossana; Levine, Myron; Prado, Valeria

    2004-01-01

    A multiplex PCR for detection of three categories of diarrheagenic Escherichia coli was developed. With this method, enterohemorrhagic E. coli, enteropathogenic E. coli, and enterotoxigenic E. coli were identified in fecal samples from patients with hemorrhagic colitis, watery diarrhea, or hemolytic-uremic syndrome and from food-borne outbreaks.

  13. Binding of Escherichia coli S fimbriae to human kidney epithelium

    Korhonen, T K; Parkkinen, J; Hacker, Jörg; Finne, J; Pere, A; Rhen, M; Holthöfer, H

    2011-01-01

    Purified S fimbriae and an Escherichia coli strain carrying the recombinant plasmid pANN801-4 that encodes S fimbriae were tested for adhesion to frozen sections of human kidney. The fimbriae and the bacteria bound to the same tissue domains, and in both cases the binding was specifically inhibited by the receptor analog of S fimbria, sialyl(alpha 2-3)lactose. S fimbriae bound specifically to the epithelial elements in the kidneys; to the epithelial cells of proximal and distal tubules as wel...

  14. Characterization of RNA damage under oxidative stress in Escherichia coli

    Liu, Min; Gong, Xin; Alluri, Ravi Kumar; Wu, Jinhua; Sablo, Tene’; Li, Zhongwei

    2012-01-01

    We have examined the level of 8-hydroxyguanosine (8-oxo-G), an oxidized form of guanosine, in RNA in Escherichia coli under normal and oxidative stress conditions. The level of 8-oxo-G in RNA rises rapidly and remains high for hours in response to hydrogen peroxide (H2O2) challenge in a dose-dependent manner. H2O2 induced elevation of 8-oxo-G content is much higher in RNA than that of 8-hydroxydeoxyguanosine (8-oxo-dG) in DNA. Under normal conditions, the 8-oxo-G level is low in RNA isolated ...

  15. Effect of Zinc in Enteropathogenic Escherichia coli Infection▿ †

    Crane, John K.; Naeher, Tonniele M.; Shulgina, Irina; Zhu, Chengru; Boedeker, Edgar C.

    2007-01-01

    Enteropathogenic Escherichia coli (EPEC) infection triggers the release of ATP from host intestinal cells, and the ATP is broken down to ADP, AMP, and adenosine in the lumen of the intestine. Ecto-5′-nucleotidase (CD73) is the main enzyme responsible for the conversion of 5′-AMP to adenosine, which triggers fluid secretion from host intestinal cells and also has growth-promoting effects on EPEC bacteria. In a recent study, we examined the role of the host enzyme CD73 in EPEC infection by test...

  16. Replication initiation at the Escherichia coli chromosomal origin

    Kaguni, Jon M.

    2011-01-01

    To initiate DNA replication, DnaA recognizes and binds to specific sequences within the Escherichia coli chromosomal origin (oriC), and then unwinds a region within oriC. Next, DnaA interacts with DnaB helicase in loading the DnaB-DnaC complex on each separated strand. Primer formation by primase (DnaG) induces the dissociation of DnaC from DnaB, which involves the hydrolysis of ATP bound to DnaC. Recent evidence indicates that DnaC acts as a checkpoint in the transition from initiation to th...

  17. Tetrahydrothiophene 1-oxide as an electron acceptor for Escherichia coli.

    Meganathan, R; Schrementi, J

    1987-01-01

    Escherichia coli used tetrahydrothiophene 1-oxide (THTO) as an electron acceptor for anaerobic growth with glycerol as a carbon source; the THTO was reduced to tetrahydrothiophene. Cell extracts also reduced THTO to tetrahydrothiophene in the presence of a variety of electron donors. Chlorate-resistant (chl) mutants (chlA, chlB, chlD, and chlE) were unable to grow with THTO as the electron acceptor. However, growth and THTO reduction by the chlD mutant were restored by high concentrations of ...

  18. Multiple joined genes prevent product degradation in Escherichia coli.

    Shen, S H

    1984-01-01

    A method is described that allows the expression of a stable human proinsulin product in Escherichia coli as encoded by either a fused or an unfused gene construction. In the fused system, the human proinsulin coding sequence is joined to the 3' side of a fragment containing the lac promoter and the coding sequence for a small part of the NH2 terminus of beta-galactosidase. In the unfused system, the proinsulin coding sequence is linked directly to a fragment containing the Tac promoter follo...

  19. Carbon and energy metabolism of atp mutants of Escherichia coli

    Jensen, Peter Ruhdal; Michelsen, Ole

    1992-01-01

    The membrane-bound H+-ATPase plays a key role in free-energy transduction of biological systems. We report how the carbon and energy metabolism of Escherichia coli changes in response to deletion of the atp operon that encodes this enzyme. Compared with the isogenic wild-type strain, the growth...... rate and growth yield were decreased less than expected for a shift from oxidative phosphorylation to glycolysis alone as a source of ATP. Moreover, the respiration rate of a atp deletion strain was increased by 40% compared with the wild-type strain. This result is surprising, since the atp deletion...

  20. Transcriptional Response of Escherichia coli to External Zinc

    Yamamoto, Kaneyoshi; Ishihama, Akira

    2005-01-01

    Transcriptional response of Escherichia coli to extracellular zinc was studied using DNA microarray and S1 mapping assays. Addition of external zinc induced the expression of zinc exporter ZntA and inhibited the expression of zinc importer ZnuC. In the continuous presence of zinc, ZnuC repression took place at lower zinc concentrations than ZntA induction. The microarray assay indicated that the addition of excess external zinc induces the expression of many genes that are organized in the re...

  1. Rapid test for assay of ozone sensitivity in Escherichia coli

    A rapid test devised for assay of ozone sensitivity in Escherichia coli based on the procedure used by Chung and Greenberg (1968) for assay of radiation sensitivity is described. The detection of new mutants, either more resistant or more sensitive than wild type strain to ozone, and the genetic analysis of ozone recombinants are now possible. Results confirm that ozone resistance is probably involved with DNA repair mechanisms; and show that ozone and ultraviolet light inhibit the cell division capacity of lon mutants in a similar way. (orig.)

  2. Dual genetic selection of synthetic riboswitches in Escherichia coli.

    Nomura, Yoko; Yokobayashi, Yohei

    2014-01-01

    This chapter describes a genetic selection strategy to engineer synthetic riboswitches that can chemically regulate gene expression in Escherichia coli. Riboswitch libraries are constructed by randomizing the nucleotides that potentially comprise an expression platform and fused to the hybrid selection/screening marker tetA-gfpuv. Iterative ON and OFF selections are performed under appropriate conditions that favor the survival or the growth of the cells harboring the desired riboswitches. After the selection, rapid screening of individual riboswitch clones is performed by measuring GFPuv fluorescence without subcloning. This optimized dual genetic selection strategy can be used to rapidly develop synthetic riboswitches without detailed computational design or structural knowledge. PMID:24549616

  3. Identification, Expression, and Characterization of Escherichia coli Guanine Deaminase

    Maynes, Jason T.; Yuan, Richard G.; Snyder, Floyd F.

    2000-01-01

    Using the human cDNA sequence corresponding to guanine deaminase, the Escherichia coli genome was scanned using the Basic Local Alignment Search Tool (BLAST), and a corresponding 439-residue open reading frame of unknown function was identified as having 36% identity to the human protein. The putative gene was amplified, subcloned into the pMAL-c2 vector, expressed, purified, and characterized enzymatically. The 50.2-kDa protein catalyzed the conversion of guanine to xanthine, having a Km of ...

  4. Modulation of allele leakiness and adaptive mutability in Escherichia coli

    R. Jayaraman

    2000-08-01

    It is shown that partial phenotypic suppression of two ochre mutations (argE3 and lacZU118) and an amber mutation (in argE) by sublethal concentrations of streptomycin in an rpsL+ (streptomycin-sensitive) derivative of the Escherichia coli strain AB1157 greatly enhances their adaptive mutability under selection. Streptomycin also increases adaptive mutability brought about by the ppm mutation described earlier. Inactivation of recA affects neither phenotypic suppression by streptomycin nor replication-associated mutagenesis but abolishes adaptive mutagenesis. These results indicate a causal relationship between allele leakiness and adaptive mutability.

  5. relA-dependent RNA polymerase activity in Escherichia coli.

    Ryals, J; Bremer, H

    1982-01-01

    Parameters relating to RNA synthesis were measured after a temperature shift from 30 to 42 degrees C, in a relA+ and relA- isogenic pair of Escherichia coli strains containing a temperature-sensitive valyl tRNA synthetase. The following results were obtained: (i) the rRNA chain growth rate increased 2-fold in both strains; (ii) newly synthesized rRNA became unstable in both strains; (iii) the stable RNA gene activity (rRNA and tRNA, measured as stable RNA synthesis rate relative to the total ...

  6. The action of beta-galactosidase (Escherichia coli) on allolactose.

    Huber, R E; Wallenfels, K; Kurz, G

    1975-09-01

    The parameters involved in the action of beta-galactosidase (EC 3.2.1.23) (Escherichia coli) on allolactose, the natural inducer of lac operon in E. coli, were studied. At low allolactose concentrations only galactose and glucose were formed, while at high allolactose concentrations transgalactolytic oligosaccharides were also produced. Detectable amounts of lactose were not formed. The V and Km values (49.6 U/mg and 0.00120 M, respectively) indicated that allolactose is as good if not a better substrate of beta-galactosidase as lactose. The pH optimum with allolactose (7.8-7.9) as well as its activation by K+ (as compared to activation by Na+) were similar to the case with lactose as substrate. The alpha-anomer of allolactose was hydrolyzed about two times as rapidly as was the beta-anomer. PMID:241475

  7. Antimicrobial activity of peptidomimetics against multidrug-resistant Escherichia coli

    Jahnsen, Rasmus D; Frimodt-Møller, Niels; Franzyk, Henrik

    2012-01-01

    Novel remedies in the battle against multidrug-resistant bacterial strains are urgently needed, and one obvious approach involves antimicrobial peptides and mimics hereof. The impact of a- and ß-peptoid as well as ß(3)-amino acid modifications on the activity profile against ß......-lactamase-producing Escherichia coli was assessed by testing an array comprising different types of cationic peptidomimetics obtained by a general monomer-based solid-phase synthesis protocol. Most of the peptidomimetics possessed high to moderate activity toward multidrug-resistant E. coli as opposed to the corresponding...... inactive peptides. Nevertheless, differences in hemolytic activities indicate that a careful choice of backbone design constitutes a significant parameter in the search for effective cationic antimicrobial peptidomimetics targeting specific bacteria....

  8. Human Insulin Modulation of Escherichia coli Adherence and Chemotaxis

    Karolina Klosowska

    2006-01-01

    Full Text Available Escherichia coli exhibited increased hydrophobicity and mannose-resistant epithelial cell adherence after growth in the presence of human insulin (2 µU mLˉ1 or 200 µUmLˉ1 insulin, respectively with glucose (100 mg dLˉ1. Capsule production and hemagglutination were unaffected by insulin and glucose. Chemotactic attraction to glucose as compared to insulin or glucose alone was enhanced by the presence of insulin. Insulin alone (200 µU mLˉ1 was a chemorepellent and inhibited flagellar tethering to glass. These findings indicate that human insulin can modulate E. coli’s expression of factors associated with pathogenesis in a manner that is modifiable by the presence of glucose.

  9. Engineering Escherichia coli Cell Factories for n-Butanol Production.

    Dong, Hongjun; Zhao, Chunhua; Zhang, Tianrui; Lin, Zhao; Li, Yin; Zhang, Yanping

    2016-01-01

    The production of n-butanol, as a widely applied solvent and potential fuel, is attracting much attention. The fermentative production of butanol coupled with the production of acetone and ethanol by Clostridium (ABE fermentation) was once one of the oldest biotechnological processes, ranking second in scale behind ethanol fermentation. However, there remain problems with butanol production by Clostridium, especially the difficulty in genetically manipulating clostridial strains. In recent years, many efforts have been made to produce butanol using non-native strains. Until now, the most advanced effort was the engineering of the user-friendly and widely studied Escherichia coli for butanol production. This paper reviews the current progress and problems relating to butanol production by engineered E. coli in terms of prediction using mathematical models, pathway construction, novel enzyme replacement, butanol toxicity, and tolerance engineering strategies. PMID:25662903

  10. Impact of cranberry on Escherichia coli cellular surface characteristics

    The anti-adhesive effects of cranberry have been attributed to both interactions of its components with the surface of bacterial cells and to inhibition of p-fimbriae expression. Previous reports also suggested that the presence of cranberry juice changed the Gram stain characteristics of Escherichia coli. Here, we show that the morphology of E. coli is changed when grown in the presence of juice or extract from Vaccinium macrocarpon (cranberry). Gene expression analysis indicates the down regulation of flagellar basal body rod and motor proteins. Consistent with this finding and previous reports, the SEM images indicate a decrease in the visible p-fimbriae. The iodine used in Gram-staining protocols was found to interact differently with the bacterial membrane when cells were cultured in spiked media. Slight alterations in the Gram stain protocol demonstrated that culturing in the presence of cranberry juice does not change the Gram stain characteristics contradicting other reports.

  11. Sickness behavior in dairy cows during Escherichia coli mastitis

    Fogsgaard, Katrine Kop; Røntved, Christine Maria; Sørensen, Peter;

    2012-01-01

    -recorded on 5 consecutive days, d −2 to +2 after challenge when the cows were not disturbed by humans. The behavior of the animals was compared among all days. Infection with E. coli altered the behavior of the dairy cows. Time spent feeding was lower in the initial 24 h after infection compared with that on......The consequences of mastitis in terms of dairy cow behavior are relatively unknown. Future assessment of dairy cow welfare during mastitis will be facilitated by knowledge about the potential of mastitis to induce sickness behavior. Our aim was to examine behavior of dairy cows in the period from 2...... d before (d −2 and −1) to 3 d (d 0, 1, and 2) after experimental intramammary challenge with Escherichia coli. Effects of experimentally induced mastitis on behavior were examined in 20 primiparous Danish Holstein-Friesian cows, all 3 to 6 wk after calving and kept in tie stalls. After evening...

  12. Assessment of Escherichia coli isolates for In vitro biofilm production

    A.I. Dadawala

    Full Text Available A total of 14 Escherichia coli isolates were assessed for their ability to produce biofilm in-vitro by slime production on Congo red agar medium (CRA and microtitre plate assay. Out of 14 isolates tested, 12 were slime producing on CRA as indicated by black colonies. The isolates of E.coli varied in their ability to produce biofilm on the surface of microtitre plate ranging from 0.101 to 0.543 ODm. Out of 14 isolates tested, 10 were positive for biofilm production employing criterion of blank corrected ODs9s > 0.1. Two of slime negative isolated were also negative for biofilm production where as the two slime positive isolates were found to be negative for biofilm production. [Veterinary World 2010; 3(8.000: 364-366

  13. Metabolite essentiality elucidates robustness of Escherichia coli metabolism

    Kim, Pan-Jun; Kim, Tae Yong; Lee, Kwang Ho; Jeong, Hawoong; Lee, Sang Yup; Park, Sunwon

    2007-01-01

    Complex biological systems are very robust to genetic and environmental changes at all levels of organization. Many biological functions of Escherichia coli metabolism can be sustained against single-gene or even multiple-gene mutations by using redundant or alternative pathways. Thus, only a limited number of genes have been identified to be lethal to the cell. In this regard, the reaction-centric gene deletion study has a limitation in understanding the metabolic robustness. Here, we report the use of flux-sum, which is the summation of all incoming or outgoing fluxes around a particular metabolite under pseudo-steady state conditions, as a good conserved property for elucidating such robustness of E. coli from the metabolite point of view. The functional behavior, as well as the structural and evolutionary properties of metabolites essential to the cell survival, was investigated by means of a constraints-based flux analysis under perturbed conditions. The essential metabolites are capable of maintaining a...

  14. In Vivo study of naturally deformed Escherichia coli bacteria.

    Tavaddod, Sharareh; Naderi-Manesh, Hossein

    2016-06-01

    A combination of light-microscopy and image processing has been applied to study naturally deformed Escherichia coli under in vivo condition and at the order of sub-pixel high-resolution accuracy. To classify deflagellated non-dividing E. coli cells to the rod-shape and bent-shape, a geometrical approach has been applied. From the analysis of the geometrical data which were obtained of image processing, we estimated the required effective energy for shaping a rod-shape to a bent-shape with the same size. We evaluated the energy of deformation in the naturally deformed bacteria with minimum cell manipulation, under in vivo condition, and with minimum influence of any external force, torque and pressure. Finally, we have also elaborated on the possible scenario to explain how naturally deformed bacteria are formed from initial to final-stage. PMID:27026097

  15. Deactivation of Escherichia coli by the plasma needle

    Sladek, R E J; Stoffels, E [Department of Biomedical Engineering, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven (Netherlands)

    2005-06-07

    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 plaque and treatment of caries. We use E. coli films plated on agar dishes as a model system to optimize the conditions for bacterial destruction. Plasma power, treatment time and needle-to-sample distance are varied. Plasma treatment of E. coli films results in formation of a bacteria-free void with a size up to 12 mm. 10{sup 4}-10{sup 5} colony forming units are already destroyed after 10 s of treatment. Prolongation of treatment time and usage of high powers do not significantly improve the destruction efficiency: short exposure at low plasma power is sufficient. Furthermore, we study the effects of temperature increase on the survival of E. coli and compare it with thermal effects of the plasma. The population of E. coli heated in a warm water bath starts to decrease at temperatures above 40 deg. C. Sample temperature during plasma treatment has been monitored. The temperature can reach up to 60 deg. C at high plasma powers and short needle-to-sample distances. However, thermal effects cannot account for bacterial destruction at low power conditions. For safe and efficient in vivo disinfection, the sample temperature should be kept low. Thus, plasma power and treatment time should not exceed 150 mW and 60 s, respectively.

  16. Deactivation of Escherichia coli by the plasma needle

    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 plaque and treatment of caries. We use E. coli films plated on agar dishes as a model system to optimize the conditions for bacterial destruction. Plasma power, treatment time and needle-to-sample distance are varied. Plasma treatment of E. coli films results in formation of a bacteria-free void with a size up to 12 mm. 104-105 colony forming units are already destroyed after 10 s of treatment. Prolongation of treatment time and usage of high powers do not significantly improve the destruction efficiency: short exposure at low plasma power is sufficient. Furthermore, we study the effects of temperature increase on the survival of E. coli and compare it with thermal effects of the plasma. The population of E. coli heated in a warm water bath starts to decrease at temperatures above 40 deg. C. Sample temperature during plasma treatment has been monitored. The temperature can reach up to 60 deg. C at high plasma powers and short needle-to-sample distances. However, thermal effects cannot account for bacterial destruction at low power conditions. For safe and efficient in vivo disinfection, the sample temperature should be kept low. Thus, plasma power and treatment time should not exceed 150 mW and 60 s, respectively

  17. Longitudinal characterization of Escherichia coli in healthy captive nonhuman primates

    Jonathan B Clayton

    2014-11-01

    Full Text Available The gastrointestinal (GI tracts of nonhuman primates are well known to harbor Escherichia coli, a known commensal of humans and animals. While E. coli is a normal inhabitant of the mammalian gut, it also exists in a number of pathogenic forms or pathotypes, including those with predisposition for the GI tract, as well the urogenital tract. Diarrhea in captive nonhuman primates (NHPs has long been a problem in both zoo settings and research colonies, including the Como Zoo. It is an animal welfare concern, as well as a public health concern. E. coli has not been extensively studied in correlation with diarrhea in captive primates; therefore, a study was performed during the summer of 2009 in collaboration with a zoo in Saint Paul, MN, which was experiencing an increased incidence and severity of diarrhea among their NHP collection. Fresh fecal samples were collected weekly from each member of the primate collection, between June and August of 2009, and E. coli were isolated. A total of 33 individuals were included in the study, representing eight species. E. coli isolates were examined for their genetic relatedness, phylogenetic relationships, plasmid replicon types, virulence gene profiles, and antimicrobial susceptibility profiles. A number of isolates were identified containing virulence genes commonly found in several different E. coli pathotypes, and there was evidence of clonal transmission of isolates between animals and over time. Overall, the manifestation of chronic diarrhea in the Como Zoo primate collection is a complex problem whose solution will require regular screening for microbial agents and consideration of environmental causes. This study provides some insight towards the sharing of enteric bacteria between such animals.

  18. ASSOCIATION OF ESCHERICHIA COLI WITH THE PREVALENCE OF FLIES POPULATION

    Hassan Flayiah Hassan

    2013-01-01

    Full Text Available Mass releases of house fly Musca domestica (L and stable fly Stomoxys calcitrans (L. Produced by manure piles accumulated nearby horse stables and dairy farm village in Abu-Graib provide continuous threat to inhabitants west of Baghdad. Timing of fly’s mass release in association with the presence of Escherichia coli in manure piles was examined at these locations. Experimental result indicated that flies survived during cold period of December and January in form of larvae deep in manure piles where temperature was around 15-17°C. Once the population of fly’s larvae started to increase by the second week of February, the concentration of E. coli was up to 80×106 CFU mL-1 in manure suspension. Later when larval population reached to a maximum number by the last week of April, the concentration of E. coli in manure sample dropped down to 38×102 CFU mL-1. Similar trend was observed with the proportion of E. coli to general bacteria present in manure samples where the percent decreased from 89% in early season to 1.5% when maximum number of larvae was recorded. The correlation coefficient (R between the number of larvae and coli form bacteria was = -0.73657. These results suggest the association of larval development with the consumption of E. coli. Thus manipulation of bacterial community in manure piles may lead to possible eradication of fly’s seasonal release.

  19. Modification of Artificial Oliogosaccharides in Recombinant Escherichia coli Cells

    Tomohisa Kato

    2008-01-01

    Full Text Available Artificial oligosaccharides were modified using recombinant Escherichia coli cells that overexpress sialidase. Based on the principle of the saccharide primer method by using bacterial cells overexpressing enzymes related to oligosaccharide modification. Problem statement: It is very hard to obtain oligosaccharides, because they have complex and diverse structures with different linkage patterns and monosaccharide components. Approach: It has been known that various oligosaccharides can be synthesized in mammalian cells from saccharide primers. We attempted to modify oligosaccharides by using bacterial cells overexpressing enzymes related to oligosaccharide modification instead of mammalian cells. Results: The glycosphingolipid-like derivative GM3 was absorbed by the cell and desialylated by the expressed sialidase and the desialylated product was then secreted into the medium. The GM3-type oligosaccharides were not detected from the cell fraction of recombinant E. coli cells that overexpress sialidase differently from recombinant E. coli carrying only vector DNA (pET-19b. Conclusion/Recommendations: E. coli as well as mammalian cells may be used as a biocatalyst for oligosaccharide modification and production of artificial functional oligosaccharides.

  20. Modeling Escherichia coli removal in constructed wetlands under pulse loading.

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

    2014-03-01

    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

  1. REVIEW VIRULENCE NATURE OF Escherichia coli IN NEONATAL SWINE

    Nwiyi PAUL

    2015-11-01

    Full Text Available Piglet disease due to Enterotoxigenic Escherichia coli (ETEC are classical and associated typically with severe watery diarrhea within the first two weeks of life and occasionally some days after weaning in pigs. E.coli is a well-known and diverse organism though normally harmless commensal, but when it acquires mobile genetic elements becomes a highly pathogenic organism capable of causing a range of diseases. ETEC adhere to the small intestinal microvilli without inducing morphological lesions and produce enterotoxins acting locally on enterocytes. This leads to hyper-secretions and reduced absorption of electrolytes. The virulence attributes of ETEC are adhesions and toxins and the successful management of the disease is dependent on good understanding of these virulence factors. In pigs ETEC, the commonest adhesions are the fimbriae on the surface K88, K99, 987p, F18ab and F18ac. The enterotoxine of pigs ETEC are further classified into heat-labile (LT and heat-stable (ST. Other subdivisions of enterotoxin E. coli are LT, STb, STa, Stx2e. The adhesive fimbriae and enterotoxins of piglet ETEC can be evaluated using plasmids. Polymerase chain reaction (PCR is a specific test and had been used for virulence gene detection of ETEC. In this reviews, we focus on current opinions and knowledge of the various pathogenic pathways that E.coli uses to cause disease in piglet.

  2. Persistence of colicinogenic Escherichia coli in the mouse gastrointestinal tract

    Giladi Itamar

    2009-08-01

    Full Text Available Abstract Background The ability of a bacterial strain to competitively exclude or displace other strains can be attributed to the production of narrow spectrum antimicrobials, the bacteriocins. In an attempt to evaluate the importance of bacteriocin production for Escherichia coli strain residence in the gastrointestinal tract, a murine model experimental evolution study was undertaken. Results Six colicin-producing, yet otherwise isogenic, E. coli strains were administered and established in the large intestine of streptomycin-treated mice. The strains' persistence, population density, and doubling time were monitored over a period of 112 days. Early in the experiment only minor differences in population density between the various colicin-producing and the non-producing control strains were detected. However, over time, the density of the control strains plummeted, while that of the colicin-producing strains remained significantly higher (F(7,66 = 2.317; P Conclusion The data presented here support prior claims that bacteriocin production may play a significant role in the colonization of E. coli in the gastrointestinal tract. Further, this study suggests that the ability to produce bacteriocins may prove to be a critical factor in determining the success of establishing probiotic E. coli in the gastrointestinal tract of humans and animals.

  3. Prevalence of Antibiotic Resistance in Escherichia coli Isolated from Poultry Meat Supply in Isfahan

    Farhad Safarpordehkordi

    2014-08-01

    Conclusions: Despite the high contamination rate of chicken meat with Escherichia coli, majority of isolates had high resistance to common antibiotics. Complete cooking of meat and avoid indiscriminate prescribing of antibiotics, preventing the occurrence of food poisoning due to resistant Escherichia coli.

  4. Kinetics of Schiff base on Escherichia coli by microcalorimetry

    许名飞; 李新海; 万洪文; 刘义

    2003-01-01

    The influence of four kinds of Schiff bases on a strain of Escherichia coli was studied by microcalorimetry. Differences in their capabilities of suppressing the metabolism of this bacterium were observed. The results show that the extent and duration of the inhibitory effect on the metabolism as judged from the multiplication rate constant, k, varies with different Schiff bases.The multiplication rate constant k, of Escherichia coli (in log phase) in the presence of Mo-salicylioaldehyde-thiadizole, Mo-piperonaldehyde-thiosemicarbazone and Mo-3-methoxy-salicylicaldehyde-thiadizole decreases with the increase of concentrations of compounds c, and the relationships between k and c, maximum heat production rate Pm and c, peak time of growth curves tp and c are of linearity. For Mo-6-nitro-pieronalde-thiosemicarbazone, the multiplication rate constant is constant irrespective of variation in concentration. The sequence of antibiotic activity of Schiff base is: Mo-salicylioaldehyde-thiadizole>Mo-3-methoxy-salicylicaldehyde-thiadizole>Mo-piperonaldehyde-thiosemicarbazone> 6-nitro-pieronalde-thiosemicarbazone.

  5. Growth of the modeling of Escherichia coli in milk

    Escherichia coli is a contaminant potential of milk. Collective toxinfections implying the bacterium and milk were announced of share the world. However, no identified work proposed a mathematical expression of the growth of the bacterium in milk. The interest of such a step is however undeniable. Under specified conditions, the mathematical formulation of the growth provides the means of considering the population bacterial when the analyses cannot be carried out. It also makes it possible to test the negatiable instruments of the unfavourable circumstances supposed suchas chain breakage of cold on the development of the microbial charge. This work established mathematical expressions of the growth of Escherichia coli in milk for part of its range of temperature of growth suboptimale i.e. between 25 and 35 Deg C. It was not possible to generalize these expressions for predictions on all the range of temperature suboptimal. This work also made it possible to highlight a deviation of the behavoir of the bacterium compared to the model of Ratkowsky without however that it is not possible to provide a univocal explanantion of it. Varoius assumptions were put forth referring to either a singularity of the behavior of the bacterium or a skew of the value of its minimal temperature of growth

  6. Genetic determinants of heat resistance in Escherichia coli

    Ryan eMercer

    2015-09-01

    Full Text Available Escherichia coli AW1.7 is a heat resistant food isolate and the occurrence of pathogenic strains with comparable heat resistance may pose a risk to food safety. To identify the genetic determinants of heat resistance, 29 strains of E. coli that differed in their of heat resistance were analyzed by comparative genomics. Strains were classified as highly heat resistant strains, exhibiting a D60-value of more than 6 min; moderately heat resistant strains, exhibiting a D60-value of more than 1 min; or as heat sensitive. A ~14 kb genomic island containing 16 predicted open reading frames encoding putative heat shock proteins and proteases was identified only in highly heat resistant strains. The genomic island was termed the locus of heat resistance (LHR. This putative operon is flanked by mobile elements and possesses >99% sequence identity to genomic islands contributing to heat resistance in Cronobacter sakazakii and Klebsiella pneumoniae. An additional 41 LHR sequences with >87% sequence identity were identified in 11 different species of β- and γ-proteobacteria. Cloning of the full length LHR conferred high heat resistance to the heat sensitive E. coli AW1.7ΔpHR1 and DH5α. The presence of the LHR correlates perfectly to heat resistance in several species of Enterobacteriaceae and occurs at a frequency of 2% of all E. coli genomes, including pathogenic strains. This study suggests the LHR has been laterally exchanged among the β- and γ-proteobacteria and is a reliable indicator of high heat resistance in E. coli.

  7. Anaerobic respiration of Escherichia coli in the mouse intestine.

    Jones, Shari A; Gibson, Terri; Maltby, Rosalie C; Chowdhury, Fatema Z; Stewart, Valley; Cohen, Paul S; Conway, Tyrrell

    2011-10-01

    The intestine is inhabited by a large microbial community consisting primarily of anaerobes and, to a lesser extent, facultative anaerobes, such as Escherichia coli, which we have shown requires aerobic respiration to compete successfully in the mouse intestine (S. A. Jones et al., Infect. Immun. 75:4891-4899, 2007). If facultative anaerobes efficiently lower oxygen availability in the intestine, then their sustained growth must also depend on anaerobic metabolism. In support of this idea, mutants lacking nitrate reductase or fumarate reductase have extreme colonization defects. Here, we further explore the role of anaerobic respiration in colonization using the streptomycin-treated mouse model. We found that respiratory electron flow is primarily via the naphthoquinones, which pass electrons to cytochrome bd oxidase and the anaerobic terminal reductases. We found that E. coli uses nitrate and fumarate in the intestine, but not nitrite, dimethyl sulfoxide, or trimethylamine N-oxide. Competitive colonizations revealed that cytochrome bd oxidase is more advantageous than nitrate reductase or fumarate reductase. Strains lacking nitrate reductase outcompeted fumarate reductase mutants once the nitrate concentration in cecal mucus reached submillimolar levels, indicating that fumarate is the more important anaerobic electron acceptor in the intestine because nitrate is limiting. Since nitrate is highest in the absence of E. coli, we conclude that E. coli is the only bacterium in the streptomycin-treated mouse large intestine that respires nitrate. Lastly, we demonstrated that a mutant lacking the NarXL regulator (activator of the NarG system), but not a mutant lacking the NarP-NarQ regulator, has a colonization defect, consistent with the advantage provided by NarG. The emerging picture is one in which gene regulation is tuned to balance expression of the terminal reductases that E. coli uses to maximize its competitiveness and achieve the highest possible population in

  8. Immobilizing live Escherichia coli for AFM studies of surface dynamics

    Atomic force microscopy (AFM) is a probe-based technique that permits high resolution imaging of live bacterial cells. However, stably immobilizing cells to withstand the probe-based lateral forces remains an obstacle in AFM mediated studies, especially those of live, rod shaped bacteria in nutrient media. Consequently, AFM has been under-utilized in the research of bacterial surface dynamics. The aim of the current study was to immobilize a less adherent Escherichia coli strain in a method that both facilitates AFM imaging in nutrient broth and preserves overall cell viability. Immobilization reagents and buffers were systematically evaluated and the cell membrane integrity was monitored in all sample preparations. As expected, the biocompatible gelatin coated surfaces facilitated stable cell attachment in lower ionic strength buffers, yet poorly immobilized cells in higher ionic strength buffers. In comparison, poly-L-lysine surfaces bound cells in both low and high ionic strength buffers. The benefit of the poly-L-lysine binding capacity was offset by the compromised membrane integrity exhibited by cells on poly-L-lysine surfaces. However, the addition of divalent cations and glucose to the immobilization buffer was found to mitigate this unfavorable effect. Ultimately, immobilization of E. coli cells on poly-L-lysine surfaces in a lower ionic strength buffer supplemented with Mg2+ and Ca2+ was determined to provide optimal cell attachment without compromising the overall cell viability. Cells immobilized in this method were stably imaged in media through multiple division cycles. Furthermore, permeability assays indicated that E. coli cells recover from the hypoosmotic stress caused by immobilization in low ionic strength buffers. Taken together, this data suggests that stable immobilization of viable cells on poly-L-lysine surfaces can be accomplished in lower ionic strength buffers that are supplemented with divalent cations for membrane stabilization while

  9. Immobilizing live Escherichia coli for AFM studies of surface dynamics

    Lonergan, N.E.; Britt, L.D.; Sullivan, C.J., E-mail: sullivcj@evms.edu

    2014-02-01

    Atomic force microscopy (AFM) is a probe-based technique that permits high resolution imaging of live bacterial cells. However, stably immobilizing cells to withstand the probe-based lateral forces remains an obstacle in AFM mediated studies, especially those of live, rod shaped bacteria in nutrient media. Consequently, AFM has been under-utilized in the research of bacterial surface dynamics. The aim of the current study was to immobilize a less adherent Escherichia coli strain in a method that both facilitates AFM imaging in nutrient broth and preserves overall cell viability. Immobilization reagents and buffers were systematically evaluated and the cell membrane integrity was monitored in all sample preparations. As expected, the biocompatible gelatin coated surfaces facilitated stable cell attachment in lower ionic strength buffers, yet poorly immobilized cells in higher ionic strength buffers. In comparison, poly-L-lysine surfaces bound cells in both low and high ionic strength buffers. The benefit of the poly-L-lysine binding capacity was offset by the compromised membrane integrity exhibited by cells on poly-L-lysine surfaces. However, the addition of divalent cations and glucose to the immobilization buffer was found to mitigate this unfavorable effect. Ultimately, immobilization of E. coli cells on poly-L-lysine surfaces in a lower ionic strength buffer supplemented with Mg{sup 2+} and Ca{sup 2+} was determined to provide optimal cell attachment without compromising the overall cell viability. Cells immobilized in this method were stably imaged in media through multiple division cycles. Furthermore, permeability assays indicated that E. coli cells recover from the hypoosmotic stress caused by immobilization in low ionic strength buffers. Taken together, this data suggests that stable immobilization of viable cells on poly-L-lysine surfaces can be accomplished in lower ionic strength buffers that are supplemented with divalent cations for membrane

  10. [Improving 3-dehydroshikimate production by metabolically engineered Escherichia coli].

    Yuan, Fei; Chen, Wujiu; Jia, Shiru; Wang, Qinhong

    2014-10-01

    In the aromatic amino acid biosynthetic pathway 3-dehydroshikimate (DHS) is a key intermediate. As a potent antioxidant and important feedstock for producing a variety of important industrial chemicals, such as adipate and vanillin, DHS is of great commercial value. Here, in this study, we investigated the effect of the co-expression of aroFFBR (3-deoxy-D-arabino-heptulosonate 7-phosphate synthase mutant with tyrosine feedback-inhibition resistance) and tktA (Transketolase A) at different copy number on the production of DHS. The increased copy number of aroFFBR and tktA would enhance the production of DHS by the fold of 2.93. In order to further improve the production of DHS, we disrupted the key genes in by-product pathways of the parent strain Escherichia coli AB2834. The triple knockout strain of ldhA, ackA-pta and adhE would further increase the production of DHS. The titer of DHS in shake flask reached 1.83 g/L, 5.7-fold higher than that of the parent strain E. coli AB2834. In 5-L fed-batch fermentation, the metabolically engineered strain produced 25.48 g/L DHS after 62 h. Metabolically engineered E. coli has the potential to further improve the production of DHS. PMID:25726580

  11. Recombinant expression of Streptococcus pneumoniae capsular polysaccharides in Escherichia coli

    Kay, Emily J.; Yates, Laura E.; Terra, Vanessa S.; Cuccui, Jon; Wren, Brendan W.

    2016-01-01

    Currently, Streptococcus pneumoniae is responsible for over 14 million cases of pneumonia worldwide annually, and over 1 million deaths, the majority of them children. The major determinant for pathogenesis is a polysaccharide capsule that is variable and is used to distinguish strains based on their serotype. The capsule forms the basis of the pneumococcal polysaccharide vaccine (PPV23) that contains purified capsular polysaccharide from 23 serotypes, and the pneumococcal conjugate vaccine (PCV13), containing 13 common serotypes conjugated to CRM197 (mutant diphtheria toxin). Purified capsule from S. pneumoniae is required for pneumococcal conjugate vaccine production, and costs can be prohibitively high, limiting accessibility of the vaccine in low-income countries. In this study, we demonstrate the recombinant expression of the capsule-encoding locus from four different serotypes of S. pneumoniae within Escherichia coli. Furthermore, we attempt to identify the minimum set of genes necessary to reliably and efficiently express these capsules heterologously. These E. coli strains could be used to produce a supply of S. pneumoniae serotype-specific capsules without the need to culture pathogenic bacteria. Additionally, these strains could be applied to synthetic glycobiological applications: recombinant vaccine production using E. coli outer membrane vesicles or coupling to proteins using protein glycan coupling technology. PMID:27110302

  12. Fecal leukocytes in children infected with diarrheagenic Escherichia coli.

    Mercado, Erik H; Ochoa, Theresa J; Ecker, Lucie; Cabello, Martin; Durand, David; Barletta, Francesca; Molina, Margarita; Gil, Ana I; Huicho, Luis; Lanata, Claudio F; Cleary, Thomas G

    2011-04-01

    The purpose of this study was to determine the presence and quantity of fecal leukocytes in children infected with diarrheagenic Escherichia coli and to compare these levels between diarrhea and control cases. We analyzed 1,474 stool samples from 935 diarrhea episodes and 539 from healthy controls of a cohort study of children younger than 2 years of age in Lima, Peru. Stools were analyzed for common enteric pathogens, and diarrheagenic E. coli isolates were studied by a multiplex real-time PCR. Stool smears were stained with methylene blue and read by a blinded observer to determine the number of polymorphonuclear leukocytes per high-power field (L/hpf). Fecal leukocytes at >10 L/hpf were present in 11.8% (110/935) of all diarrheal episodes versus 1.1% (6/539) in controls (P 10 L/hpf were present in 8.5% (18/212) of diarrhea versus 1.3% (2/157) of control samples (P 10 L/hpf) with an odds ratio (OR) of 4.1 (95% confidence interval [CI], 1.08 to 15.51; P < 0.05). Although diarrheagenic E. coli was isolated with similar frequencies in diarrhea and control samples, clearly it was associated with a more inflammatory response during symptomatic infection; however, in general, these pathogens elicited a mild inflammatory response. PMID:21325554

  13. Genomic islands of uropathogenic Escherichia coli contribute to virulence.

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

    2009-06-01

    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 (Delta PAI-aspV, Delta PAI-metV, and Delta PAI-asnT) were significantly outcompeted by wild-type CFT073 in the bladders and/or kidneys following transurethral cochallenge (P Delta c2518-15) was significantly outcompeted by wild-type CFT073 in cochallenge. Strains with mutations in a type VI secretion system within the PAI-metV island did not show attenuation. The attenuation of the PAI-metV island was localized to genes c3405-10, encoding a putative phosphotransferase transport system, which is common to UPEC and avian pathogenic E. coli strains but absent from E. coli K-12. We have shown that, in addition to encoding virulence genes, genomic islands contribute to the overall fitness of UPEC strain CFT073 in vivo. PMID:19329634

  14. Identification of Diarrheagenic Escherichia coli Strains from Avian Organic Fertilizers

    Juan Puño-Sarmiento

    2014-08-01

    Full Text Available 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.

  15. Starved Escherichia coli preserve reducing power under nitric oxide stress.

    Gowers, Glen-Oliver F; Robinson, Jonathan L; Brynildsen, Mark P

    2016-07-15

    Nitric oxide (NO) detoxification enzymes, such as NO dioxygenase (NOD) and NO reductase (NOR), are important to the virulence of numerous bacteria. Pathogens use these defense systems to ward off immune-generated NO, and they do so in environments that contain additional stressors, such as reactive oxygen species, nutrient deprivation, and acid stress. NOD and NOR both use reducing equivalents to metabolically deactivate NO, which suggests that nutrient deprivation could negatively impact their functionality. To explore the relationship between NO detoxification and nutrient deprivation, we examined the ability of Escherichia coli to detoxify NO under different levels of carbon source availability in aerobic cultures. We observed failure of NO detoxification under both carbon source limitation and starvation, and those failures could have arisen from inabilities to synthesize Hmp (NOD of E. coli) and/or supply it with sufficient NADH (preferred electron donor). We found that when limited quantities of carbon source were provided, NO detoxification failed due to insufficient NADH, whereas starvation prevented Hmp synthesis, which enabled cells to maintain their NADH levels. This maintenance of NADH levels under starvation was confirmed to be dependent on the absence of Hmp. Intriguingly, these data show that under NO stress, carbon-starved E. coli are better positioned with regard to reducing power to cope with other stresses than cells that had consumed an exhaustible amount of carbon. PMID:27207837

  16. 2DBase: 2D-PAGE database of Escherichia coli.

    Vijayendran, Chandran; Burgemeister, Sebastian; Friehs, Karl; Niehaus, Karsten; Flaschel, Erwin

    2007-11-23

    We present a web-based integrated proteome database, termed 2DBase of Escherichia coli which was designed to store, compare, analyse, and retrieve various information obtained by 2D polyacrylamide gel electrophoresis and mass spectrometry. The main objectives of this database are (1) to provide the features for query and data-mining applications to access the stored proteomics data (2) to efficiently compare the specific protein spots present in the comparable proteome maps and (3) to analyse the data with the integrated classification for cellular functions of gene products of E. coli. This database currently contains 12 gels consisting of 1185 protein spots information in which 723 proteins were identified and annotated. Individual protein spots in the existing gels can be displayed, queried, analyzed, and compared in a tabular format based on various functional categories enabling quick and subsequent analyses. Our database satisfies the requirement to be a federated 2-DE database by accomplishing various tasks through a web interface providing access to a relational database system. The 2DBase of E. coli database can be accessed at http://2dbase.techfak.uni-bielefeld.de/. PMID:17904107

  17. Escherichia coli bacteria detection by using graphene-based biosensor.

    Akbari, Elnaz; Buntat, Zolkafle; Afroozeh, Abdolkarim; Zeinalinezhad, Alireza; Nikoukar, Ali

    2015-10-01

    Graphene is an allotrope of carbon with two-dimensional (2D) monolayer honeycombs. A larger detection area and higher sensitivity can be provided by graphene-based nanosenor because of its 2D structure. In addition, owing to its special characteristics, including electrical, optical and physical properties, graphene is known as a more suitable candidate compared to other materials used in the sensor application. A novel model employing a field-effect transistor structure using graphene is proposed and the current-voltage (I-V) characteristics of graphene are employed to model the sensing mechanism. This biosensor can detect Escherichia coli (E. coli) bacteria, providing high levels of sensitivity. It is observed that the graphene device experiences a drastic increase in conductance when exposed to E. coli bacteria at 0-10(5) cfu/ml concentration. The simple, fast response and high sensitivity of this nanoelectronic biosensor make it a suitable device in screening and functional studies of antibacterial drugs and an ideal high-throughput platform which can detect any pathogenic bacteria. Artificial neural network and support vector regression algorithms have also been used to provide other models for the I-V characteristic. A satisfactory agreement has been presented by comparison between the proposed models with the experimental data. PMID:26435280

  18. Metabolic engineering of Escherichia coli to produce zeaxanthin.

    Li, Xi-Ran; Tian, Gui-Qiao; Shen, Hong-Jie; Liu, Jian-Zhong

    2015-04-01

    Zeaxanthin is a high-value carotenoid that is used in nutraceuticals, cosmetics, food, and animal feed industries. Zeaxanthin is chemically synthesized or purified from microorganisms as a natural product; however, increasing demand requires development of alternative sources such as heterologous biosynthesis by recombinant bacteria. For this purpose, we molecularly engineered Escherichia coli to optimize the synthesis of zeaxanthin from lycopene using fusion protein-mediated substrate channeling as well as by the introduction of tunable intergenic regions. The tunable intergenic regions approach was more efficient compared with protein fusion for coordinating expression of lycopene β-cyclase gene crtY and β-carotene 3-hydroxylase gene crtZ. The influence of the substrate channeling effect suggests that the reaction catalyzed by CrtZ is the rate-limiting step in zeaxanthin biosynthesis. Then Pantoea ananatis, Pantoea agglomerans and Haematococcus pluvialis crtZ were compared. Because P. ananatis crtZ is superior to that of P. agglomerans or H. pluvialis for zeaxanthin production, we used it to generate a recombinant strain of E. coli BETA-1 containing pZSPBA-2(P37-crtZPAN) that produced higher amounts of zeaxanthin (11.95 ± 0.21 mg/g dry cell weight) than other engineered E. coli strains described in the literature. PMID:25533633

  19. Properties of a Clostridium thermocellum Endoglucanase Produced in Escherichia coli.

    Schwarz, W H; Gräbnitz, F; Staudenbauer, W L

    1986-06-01

    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-beta-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 degrees C and was stable for several hours at 60 degrees 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 beta-1,4 and beta-1,3 linkages such as barley beta-glucan and lichenan. PMID:16347088

  20. Multiple Antimicrobial Resistance of Escherichia coli Isolated from Chickens in Iran

    Reza Talebiyan; Mehdi Kheradmand; Faham Khamesipour; Mohammad Rabiee-Faradonbeh

    2014-01-01

    Antimicrobial agents are used extremely in order to reduce the great losses caused by Escherichia coli infections in poultry industry. In this study, 318 pathogenic Escherichia coli (APEC) strains isolated from commercial broiler flocks with coli-septicemia were examined for antimicrobials of both veterinary and human significance by disc diffusion method. Multiple resistances to antimicrobial agents were observed in all the isolates. Resistance to the antibiotics was as follows: Tylosin (88....

  1. Plasmid profiling of multidrug resistant Escherichia coli strains isolated from urinary tract infection patients

    Sabin Khadgi; Uddhav Timilsina; Basudha Shrestha

    2013-01-01

    Introduction- Urinary tract infection is a common community-acquired bacterial disease. Escherichia coli is reported to be the major cause of urinary tract infection. Aim & Objective- The study was conducted with the aim of determining the antibiotic resistance pattern and plasmid profile of multidrug resistant Escherichia coli isolated from Urinary Tract Infection patients. Materials and Method- Antibiotic susceptibility tests were performed against E. coli following the protocol for the Kir...

  2. Detection of Escherichia Coli O157:H7 in Fecal Samples in Meat Goats

    Mobley, Ray; Madden, Uford; Brooks-Walter, Alexis

    2004-01-01

    Studies have reported the isolation of Escherichia coli (E. coli)O157:H7 from pork, lamb and poultry products, and from other animals including deer, horses, dogs, birds and humans. There is limited or no information on the presence of the organism in goats. The objectives of this study were to determine if E. coli O157:H7 was naturally occurring…

  3. Mechanisms of antibiotic resistance to enrofloxacin in uropathogenic Escherichia coli in dog

    Escherichia coli (E. coli) urinary tract infections (UTIs) are becoming a serious problem both for pets and humans (zoonosis) due to the close contact and to the increasing resistance to antibiotics. Canine E. coli represents a good experimental model useful to study this pathology. Moreover, as des...

  4. Diet, fecal microbiome and Escherichia coli O157:H7 shedding in beef Cattle

    Shiga-toxigenic Escherichia coli, such as E. coli O157:H7, are foodborne zoonotic pathogens that can cause severe illness and death in humans. The gastrointestinal tract of ruminant animals has been identified as a primary habitat for E. coli O157:H7, and in cattle the terminal gastrointestinal tra...

  5. Colonization with Extraintestinal Pathogenic Escherichia coli among Nursing Home Residents and Its Relationship to Fluoroquinolone Resistance

    Maslow, Joel N.; Lautenbach, Ebbing; Glaze, Thomas; Bilker, Warren; Johnson, James R.

    2004-01-01

    In a cross-sectional fecal prevalence survey involving 49 residents of a Veterans Affairs nursing home, 59% of subjects were colonized with extraintestinal pathogenic Escherichia coli (ExPEC), 22% were colonized with adhesin-positive E. coli, and 51% were colonized with fluoroquinolone-resistant E. coli. Among 80 unique isolates, adhesins correlated negatively and aerobactin correlated positively with fluoroquinolone resistance.

  6. Characterization of pathogenic Escherichia coli isolated from humans in Austria : phenotypes, toxin gene types and epidemiology

    Wagner, M; Allerberger, F; Manafi, M; Lindner, G; Friedrich, A W; Sonntag, A-K; Foissy, H

    2004-01-01

    One hundred and ten clinical Escherichia coli isolates of serovar O157 (n = 102) and O26 (n = 8) were characterized for the presence of putative virulence genes by PCR. All but one of these isolates contained the eae gene. The EHEC-hly gene could be detected in all E. coli O157 and in 50% of E. coli

  7. Dietary interactions and interventions affecting Escherichia coli 0157 colonization and shedding in cattle

    Escherichia coli O157 is an important foodborne pathogen affecting human health and the beef cattle industry. Contamination of carcasses at slaughter is correlated to the prevalence of E. coli O157 in cattle feces. Many associations have been made between dietary factors and E. coli O157 prevalenc...

  8. Escherichia coli O157:H7, diet, and fecal microbiome in beef cattle

    Shiga-toxigenic Escherichia coli, such as E. coli O157:H7, are foodborne zoonotic pathogens that can cause severe illness and death in humans. The gastrointestinal tract of ruminant animals has been identified as a primary habitat for E. coli O157:H7, and in cattle the terminal gastrointestinal tra...

  9. Biosynthesis of two quercetin O-diglycosides in Escherichia coli.

    An, Dae Gyun; Yang, So Mi; Kim, Bong Gyu; Ahn, Joong-Hoon

    2016-06-01

    Various flavonoid glycosides are found in nature, and their biological activities are as variable as their number. In some cases, the sugar moiety attached to the flavonoid modulates its biological activities. Flavonoid glycones are not easily synthesized chemically. Therefore, in this study, we attempted to synthesize quercetin 3-O-glucosyl (1→2) xyloside and quercetin 3-O-glucosyl (1→6) rhamnoside (also called rutin) using two uridine diphosphate-dependent glycosyltransferases (UGTs) in Escherichia coli. To synthesize quercetin 3-O-glucosyl (1→2) xyloside, sequential glycosylation was carried out by regulating the expression time of the two UGTs. AtUGT78D2 was subcloned into a vector controlled by a Tac promoter without a lacI operator, while AtUGT79B1 was subcloned into a vector controlled by a T7 promoter. UDP-xyloside was supplied by concomitantly expressing UDP-glucose dehydrogenase (ugd) and UDP-xyloside synthase (UXS) in the E. coli. Using these strategies, 65.0 mg/L of quercetin 3-O-glucosyl (1→2) xyloside was produced. For the synthesis of rutin, one UGT (BcGT1) was integrated into the E. coli chromosome and the other UGT (Fg2) was expressed in a plasmid along with RHM2 (rhamnose synthase gene 2). After optimization of the initial cell concentration and incubation temperature, 119.8 mg/L of rutin was produced. The strategies used in this study thus show promise for the synthesis of flavonoid diglucosides in E. coli. PMID:26931782

  10. Isobutyraldehyde production from Escherichia coli by removing aldehyde reductase activity

    Rodriguez Gabriel M

    2012-06-01

    Full Text Available Abstract Background Increasing global demand and reliance on petroleum-derived chemicals will necessitate alternative sources for chemical feedstocks. Currently, 99% of chemical feedstocks are derived from petroleum and natural gas. Renewable methods for producing important chemical feedstocks largely remain unaddressed. Synthetic biology enables the renewable production of various chemicals from microorganisms by constructing unique metabolic pathways. Here, we engineer Escherichia coli for the production of isobutyraldehyde, which can be readily converted to various hydrocarbons currently derived from petroleum such as isobutyric acid, acetal, oxime and imine using existing chemical catalysis. Isobutyraldehyde can be readily stripped from cultures during production, which reduces toxic effects of isobutyraldehyde. Results We adopted the isobutanol pathway previously constructed in E. coli, neglecting the last step in the pathway where isobutyraldehyde is converted to isobutanol. However, this strain still overwhelmingly produced isobutanol (1.5 g/L/OD600 (isobutanol vs 0.14 g/L/OD600 (isobutyraldehyde. Next, we deleted yqhD which encodes a broad-substrate range aldehyde reductase known to be active toward isobutyraldehyde. This strain produced isobutanol and isobutyraldehyde at a near 1:1 ratio, indicating further native isobutyraldehyde reductase (IBR activity in E. coli. To further eliminate isobutanol formation, we set out to identify and remove the remaining IBRs from the E. coli genome. We identified 7 annotated genes coding for IBRs that could be active toward isobutyraldehyde: adhP, eutG, yiaY, yjgB, betA, fucO, eutE. Individual deletions of the genes yielded only marginal improvements. Therefore, we sequentially deleted all seven of the genes and assessed production. The combined deletions greatly increased isobutyraldehyde production (1.5 g/L/OD600 and decreased isobutanol production (0.4 g/L/OD600. By assessing production by

  11. Collective motion in an active suspension of Escherichia coli bacteria

    We investigate experimentally the emergence of collective motion in the bulk of an active suspension of Escherichia coli bacteria. When increasing the concentration from a dilute to a semi-dilute regime, we observe a continuous crossover from a dynamical cluster regime to a regime of ‘bio-turbulence’ convection patterns. We measure a length scale characterizing the collective motion as a function of the bacteria concentration. For bacteria fully supplied with oxygen, the increase of the correlation length is almost linear with concentration and at the largest concentrations tested, the correlation length could be as large as 24 bacterial body sizes (or 7–8 when including the flagella bundle). In contrast, under conditions of oxygen shortage the correlation length saturates at a value of around 7 body lengths. (paper)

  12. Structure of the Cyclomodulin Cif from Pathogenic Escherichia coli

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

    2008-01-01

    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.

  13. Selection of quiescent Escherichia coli with high metabolic activity.

    Sonderegger, Marco; Schümperli, Michael; Sauer, Uwe

    2005-01-01

    Sustained metabolic activity in non-growing, quiescent cells can increase the operational life-span of bio-processes and improve process economics by decoupling production from cell growth. Because of the ill-defined molecular nature of this phenotype, we developed selection protocols for the evolution of quiescent Escherichia coli mutants that exhibit high metabolic activity in ammonium starvation-induced stationary phase. The best enrichment procedures were continuously or discontinuously fed ammonium-limited chemostat cultures with a very low dilution rate of 0.03 h(-1). After 40 generations of selection, improved mutants with up to doubled catabolic rates in stationary phase were isolated. The metabolically most active clones were identified by screening for high specific glucose uptake rates during ammonium starvation-induced stationary phase in deep-well microtiter plates. PMID:15721805

  14. Overexpression of Soluble Human Thymosin Alpha 1 in Escherichia coli

    Pei-Fu CHEN; Hong-Ying ZHANG; Geng-Feng FU; Gen-Xing XU; Ya-Yi HOU

    2005-01-01

    Synthesized gene of human thymosin alpha 1 (Tα1) was inserted into pET-28a, pET-9c,pThioHis B, pGEX-2T or pBV222 and then inductively expressed in strains of Escherichia coli. Among the five expression systems, the BL21/pET-28a system provides the highest expression level of fusion protein in a soluble form, which is up to 70% of total expressed bacterial proteins as visualized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The resulting fusion protein purified through nickel affinity chromatography accounts for 2.53% of the wet bacterial pellet weight and reaches 94.5% purity by SDS-PAGE. These results indicate the potential of this expression system for high-throughput production of recombinant Tα1.

  15. Theoretical Prediction of Disrupted Min Oscillation in Flattened Escherichia coli.

    Jeff B Schulte

    Full Text Available The dynamics of the Min-protein system help Escherichia coli regulate the process of cell division by identifying the center of the cell. While this system exhibits robust bipolar oscillations in wild-type cell shapes, recent experiments have shown that when the cells are mechanically deformed into wide, flattened out, irregular shapes, the spatial regularity of these oscillations breaks down. We employ widely used stochastic and deterministic models of the Min system to simulate cells with flattened shapes. The deterministic model predicts strong bipolar oscillations, in contradiction with the experimentally observed behavior, while the stochastic model, which is based on the same reaction-diffusion equations, predicts more spatially irregular oscillations. We further report simulations of flattened but more symmetric shapes, which suggest that the flattening and lateral expansion may contribute as much to the irregular oscillation behavior as the asymmetry of the cell shapes.

  16. A series of template plasmids for Escherichia coli genome engineering.

    Deb, Shalini S; Reshamwala, Shamlan M S; Lali, Arvind M

    2016-06-01

    Metabolic engineering strategies often employ multi-copy episomal vectors to overexpress genes. However, chromosome-based overexpression is preferred as it avoids the use of selective pressure and reduces metabolic burden on the cell. We have constructed a series of template plasmids for λ Red-mediated Escherichia coli genome engineering. The template plasmids allow construction of genome integrating cassettes that can be used to integrate single copies of DNA sequences at predetermined sites or replace promoter regions. The constructed cassettes provide flexibility in terms of expression levels achieved and antibiotics used for selection, as well as allowing construction of marker-free strains. The modular design of the template plasmids allows replacement of genetic parts to construct new templates. Gene integration and promoter replacement using the template plasmids are illustrated. PMID:27071533

  17. De novo biosynthesis of Gastrodin in Escherichia coli.

    Bai, Yanfen; Yin, Hua; Bi, Huiping; Zhuang, Yibin; Liu, Tao; Ma, Yanhe

    2016-05-01

    Gastrodin, a phenolic glycoside, is the key ingredient of Gastrodia elata, a notable herbal plant that has been used to treat various conditions in oriental countries for centuries. Gastrodin is extensively used clinically for its sedative, hypnotic, anticonvulsive and neuroprotective properties in China. Gastrodin is usually produced by plant extraction or chemical synthesis, which has many disadvantages. Herein, we report unprecedented microbial synthesis of gastrodin via an artificial pathway. A Nocardia carboxylic acid reductase, endogenous alcohol dehydrogenases and a Rhodiola glycosyltransferase UGT73B6 transformed 4-hydroxybenzoic acid, an intermediate of ubiquinone biosynthesis, into gastrodin in Escherichia coli. Pathway genes were overexpressed to enhance metabolic flux toward precursor 4-hydroxybenzyl alcohol. Furthermore, the catalytic properties of the UGT73B6 toward phenolic alcohols were improved through directed evolution. The finally engineered strain produced 545mgl(-1) gastrodin in 48h. This work creates a new route to produce gastrodin, instead of plant extractions and chemical synthesis. PMID:26804288

  18. Sugar metabolism in transketolase mutants of Escherichia coli.

    Josephson, B L; Fraenkel, D G

    1974-06-01

    This paper continues the description of transketolase mutants of Escherichia coli; they are absolutely unable to grow on pentoses, but slightly "leaky" with respect to their aromatic requirement (B. L. Josephson and D. G. Fraenkel, 1969). Several experiments have explored the degree of leakiness and shown it to be low. There is little conversion of radioactive xylose to carbon dioxide. The labeling of ribose in cells grown on [1-(14)C]glucose and [2-(14)C]glucose accords with its origin being chiefly by the oxidative pathway. A mutant lacking both transketolase and gluconate-6-phosphate dehydrogenase has been constructed; it requires supplementation with pentose. Pentoses are inhibitory to growth of transketolase mutants, but high levels of pentose phosphates do not accumulate in this situation. Several experimental results are suggestive of regulation of metabolic flow in the oxidative branch of the hexose monophosphate shunt. PMID:4597996

  19. SOS response induces persistence to fluoroquinolones in Escherichia coli.

    Tobias Dörr

    2009-12-01

    Full Text Available Bacteria can survive antibiotic treatment without acquiring heritable antibiotic resistance. We investigated persistence to the fluoroquinolone ciprofloxacin in Escherichia coli. Our data show that a majority of persisters to ciprofloxacin were formed upon exposure to the antibiotic, in a manner dependent on the SOS gene network. These findings reveal an active and inducible mechanism of persister formation mediated by the SOS response, challenging the prevailing view that persisters are pre-existing and formed purely by stochastic means. SOS-induced persistence is a novel mechanism by which cells can counteract DNA damage and promote survival to fluoroquinolones. This unique survival mechanism may be an important factor influencing the outcome of antibiotic therapy in vivo.

  20. Detergent (sodium dodecyl sulfate) shock proteins in Escherichia coli

    The protein composition of Escherichia coli W3110 grown in the presence and absence of 5% sodium dodecyl sulfate (SDS) was examined by two-dimensional gel electrophoresis. In SDS-grown cells, at least 4 proteins were turned on, 13 were turned off, 15 were elevated, and 15 were depressed. The 19 unique and elevated SDS-induced spots constituted 7.91% of the total 35S-labeled protein. There was no apparent overlap between these 19 detergent (SDS) stress proteins and those of other known bacterial stress responses. The detergent stress stimulon is a distinct and independent stimulon. Its physiological relevance probably derives from the presence of bile salts in animal gastrointestinal tracts

  1. Evidence of histidine phosphorylation in isocitrate lyase from Escherichia coli

    Escherichia coli isocitrate lyase can be phosphorylated in vitro in an ATP-dependent reaction. Partially purified extracts were incubated with γ-32P-ATP and analyzed by two-dimensional polyacrylamide gel electrophoresis followed by a Western blot and autoradiography. Radioactivity was associated with the lyase only when blotting was performed under alkaline conditions. This suggests that phosphate groups are attached to the lyase via an acid-labile P-N bond rather than a more stable P-O bond. Treatment of the lyase with diethyl pyrocarbonate, a histidine modifying agent, blocks incorporation of 32P-phosphate. Treatment with phosphoramidate, a histidine phosphorylating agent, alters the isoelectric point of the lyase suggesting that the enzyme can be phosphorylated at histidine residues. Loss of catalytic activity after treatment with potato acid phosphatase indicates that isocitrate lyase activity may be modulated by phosphorylation

  2. Signaling and sensory adaptation in Escherichia coli chemoreceptors: 2015 update.

    Parkinson, John S; Hazelbauer, Gerald L; Falke, Joseph J

    2015-05-01

    Motile Escherichia coli cells track gradients of attractant and repellent chemicals in their environment with transmembrane chemoreceptor proteins. These receptors operate in cooperative arrays to produce large changes in the activity of a signaling kinase, CheA, in response to small changes in chemoeffector concentration. Recent research has provided a much deeper understanding of the structure and function of core receptor signaling complexes and the architecture of higher-order receptor arrays, which, in turn, has led to new insights into the molecular signaling mechanisms of chemoreceptor networks. Current evidence supports a new view of receptor signaling in which stimulus information travels within receptor molecules through shifts in the dynamic properties of adjoining structural elements rather than through a few discrete conformational states. PMID:25834953

  3. Uropathogenic Escherichia coli Epigenetically Manipulate Host Cell Death Pathways.

    Zhang, Zhengguo; Wang, Ming; Eisel, Florian; Tchatalbachev, Svetlin; Chakraborty, Trinad; Meinhardt, Andreas; Bhushan, Sudhanshu

    2016-04-01

    Urinary tract infections caused by uropathogenic Escherichia coli (UPEC) pathovars belong to the most frequent infections in human. It is well established that UPEC can subvert innate immune responses, but the role of UPEC in interfering with host cell death pathways is not known. Here, we show that UPEC abrogates activation of the host cell prosurvival protein kinase B signaling pathway, which results in the activation of mammalian forkhead box O (FOXO) transcription factors. Although FOXOs were localized in the nucleus and showed increased DNA-binding activity, no change in the expression levels of FOXO target genes were observed. UPEC can suppress BIM expression induced by LY249002, which results in attenuation of caspase 3 activation and blockage of apoptosis. Mechanistically, BIM expression appears to be epigenetically silenced by a decrease in histone 4 acetylation at the BIM promoter site. Taken together, these results suggest that UPEC can epigenetically silence BIM expression, a molecular switch that prevents apoptosis. PMID:26621912

  4. Chromosome segregation control by Escherichia coli ObgE GTPase.

    Foti, James J; Persky, Nicole S; Ferullo, Daniel J; Lovett, Susan T

    2007-07-01

    Escherichia coli cells depleted of the conserved GTPase, ObgE, show early chromosome-partitioning defects and accumulate replicated chromosomes in which the terminus regions are colocalized. Cells lacking ObgE continue to initiate replication, with a normal ratio of the origin to terminus. Localization of the SeqA DNA binding protein, normally seen as punctate foci, however, was disturbed. Depletion of ObgE also results in cell filamentation, with polyploid DNA content. Depletion of ObgE did not cause lethality, and cells recovered fully after expression of ObgE was restored. We propose a model in which ObgE is required to license chromosome segregation and subsequent cell cycle events. PMID:17578452

  5. Initiation of Replication in Escherichia coli

    Frimodt-Møller, Jakob

    The circular chromosome of Escherichia coli is replicated by two replisomes assembled at the unique origin and moving in the opposite direction until they meet in the less well defined terminus. The key protein in initiation of replication, DnaA, facilitates the unwinding of double-stranded DNA to...... single-stranded DNA in oriC. Although DnaA is able to bind both ADP and ATP, DnaA is only active in initiation when bound to ATP. Although initiation of replication, and the regulation of this, is thoroughly investigated it is still not fully understood. The overall aim of the thesis was to investigate...... the regulation of initiation, the effect on the cell when regulation fails, and if regulation was interlinked to chromosomal organization. This thesis uncovers that there exists a subtle balance between chromosome replication and reactive oxygen species (ROS) inflicted DNA damage. Thus, failure in...

  6. Functional biosynthesis of an allophycocyan beta subunit in Escherichia coli.

    Ge, Baosheng; Sun, Haixiang; Feng, Yang; Yang, Jinying; Qin, Song

    2009-03-01

    Allophycocyanin is a phycobiliprotein with various biological and pharmacological properties. An expression vector was constructed using CpeS as the bilin lyase for the allophycocyanin beta subunit, resulting in overexpression of a fluorescent allophycocyanin beta-subunit in Escherichia coli. A high-density cell culture was developed using a continuous feeding strategy. After 16 h of culture, the dry cell density reached 21.4 g l(-1), the expression of the allophycocyanin beta-subunit was 0.86 g l(-1) broth, and the relative chromoprotein yield was 81.4%. The recombinant protein showed spectral features similar to native allophycocyanin, which provide an efficient methodology for large-scale production of this valuable fluorescent protein. PMID:19269586

  7. Renal abscess due to Escherichia coli in a child

    V P Baradkar

    2011-01-01

    Full Text Available Among the various intraabdominal abscesses, renal abscess is a rare entity, especially in children and accounts for a number of cases of "missed diagnoses." Drainage of pus and appropriate antibiotic therapy is the gold standard for treatment. Here we report a case of left renal abscess in a 6-year-old female child secondary to renal calculus. The patient presented with abdominal pain and mild fever for three months and the diagnosis was made by X-ray in the kidney, ureter and bladder (KUB region, intravenous pyelography and ultrasonography of the abdomen. Escherichia coli was isolated from pus obtained by percutaneous drainage under sonographic guidance. The patient responded to intra-venous ceftriaxone, amikacin, and percutaneous drainage.

  8. Escherichia coli activity characterization using a laser dynamic speckle technique

    Ramírez-Miquet, Evelio E; Contreras-Alarcón, Orestes R

    2012-01-01

    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.

  9. Analysis of resynthesis tracts in repaired Escherichia coli deoxyribonucleic acid

    Excision repair of ultraviolet radiation-induced damage in a wild-type strain of Escherichia coli has been examined, using two methods for characterizing the resynthesis step of the repair process. Comparison of data obtained after both isopycnic analysis of repaired deoxyribonucleic acid and sedimentation velocity analysis of deoxyribonucleic acid after selective photolysis of bromouracil-containing repaired regions has shown that the repaired deoxyribonucleic acid molecules contain a semicontinuous distribution of sizes of repair tracts. Further analysis of our data suggests two major classes of repair patches, one about 20 to 40 nucleotides in length, and the other containing 1600 to 2000 nucleotides. Under the conditions employed, approximately 2 to 10% of the fully repaired regions are long repair patches

  10. Improvement of escherichia coli for lysine overproduction through mutagenesis

    Bacterial isolates of Escherichia coli were obtained from the irrigation channel water. One of the isolates designated SW30 NIAB produced glutamic acid in cane molasses medium and was selected for further improvement for lysine overproduction. The cells of this strain were treated with a dose of 100 u/ g/ml of NTG(N-methyl-N-nitro-N-Nitrosoguanidine), for 90 minutes. From the cell population (3x108 cells/ml) exposed to NTG, only 1-2 percent cells survived and produced colonies. Independent colonies, 100 of them that survived the dose, were secured and subcultured. These were further screened against AEC (S-(2-aminoethyl)-L-cysteine) resistance on minimal agar medium MM-12. Among these 100 colonies, 10 proved resistant to AEC at a dose of 1000 ug/ml, and out of 10, three were lysine producers and produced 0.1-0.5 gm/ltr of lysine in L-6 medium. (author)

  11. Role of verocytotoxigenic Escherichia coli in the swine production chain

    Laura Ercoli

    2015-06-01

    Full Text Available Shiga toxin-producing Escherichia coli (STEC can cause severe clinical diseases in humans, such as haemorrhagic colitis (HC and haemolytic-uremic syndrome (HUS. Although ruminants, primarily cattle, have been suggested as typical reservoirs of STEC, many food products of other origins, including pork products, have been confirmed as vehicles for STEC transmission. Only in rare cases, pork consumption is associated with severe clinical symptoms caused by high pathogenic STEC strains. However, in these outbreaks, it is unknown whether the contamination of food products occurs during swine processing or via cross-contamination from foodstuffs of different sources. In swine, STEC plays an important role in the pathogenesis of oedema disease. In particular a Shiga toxin subtype, named stx2e, it is considered as a key factor involved in the damage of swine endothelial cells. On the contrary, stx2e-producing Escherichia coli has rarely been isolated in humans, and usually only from asymptomatic carriers or from patients with mild symptoms, such as uncomplicated diarrhoea. In fact, the presence of gene stx2e, encoding for stx2e, has rarely been reported in STEC strains that cause HUS. Moreover, stx2e-producing STEC isolated from humans and pigs were found to differ in serogroup, their virulence profile and interaction with intestinal epithelial cells. Because of the limited epidemiologic data of STEC in swine and the increasing role of non-O157 STEC in human illnesses, the relationship between swine STEC and human disease needs to be further investigated.

  12. Evaluation of Petrifilm™ Select E. coli Count Plate medium to discriminate antimicrobial resistant Escherichia coli

    Jensen Lars

    2008-09-01

    Full Text Available Abstract Background Screening and enumeration of antimicrobial resistant Escherichia coli directly from samples is needed to identify emerging resistant clones and obtain quantitative data for risk assessment. Aim of this study was to evaluate the performance of 3M™ Petrifilm™ Select E. coli Count Plate (SEC plate supplemented with antimicrobials to discriminate antimicrobial-resistant and non-resistant E. coli. Method A range of E. coli isolates were tested by agar dilution method comparing the Minimal Inhibitory Concentration (MIC for eight antimicrobials obtained by Mueller-Hinton II agar, MacConkey agar and SEC plates. Kappa statistics was used to assess the levels of agreement when classifying strains as resistant, intermediate or susceptible. Results SEC plate showed that 74% of all strains agreed within ± 1 log2 dilution when comparing MICs with Mueller-Hinton II media. High agreement levels were found for gentamicin, ampicillin, chloramphenicol and cefotaxime, resulting in a kappa value of 0.9 and 100% agreement within ± 1 log2 dilution. Significant variances were observed for oxytetracycline and sulphamethoxazole. Further tests showed that the observed discrepancy in classification of susceptibility to oxytetracycline by the two media could be overcome when a plate-dependent breakpoint of 64 mg/L was used for SEC plates. For sulphamethoxazole, SEC plates provided unacceptably high MICs. Conclusion SEC plates showed good agreement with Mueller-Hinton II agar in MIC studies and can be used to screen and discriminate resistant E. coli for ampicillin, cephalothin, streptomycin, chloramphenicol, cefotaxime and gentamicin using CLSI standardized breakpoints, but not for sulphamethoxazole. SEC plates can also be used to discriminate oxytetracycline-resistant E. coli if a plate-dependent breakpoint value of 64 mg/L is used.

  13. Invariant distribution of promoter activities in Escherichia coli.

    Alon Zaslaver

    2009-10-01

    Full Text Available Cells need to allocate their limited resources to express a wide range of genes. To understand how Escherichia coli partitions its transcriptional resources between its different promoters, we employ a robotic assay using a comprehensive reporter strain library for E. coli to measure promoter activity on a genomic scale at high-temporal resolution and accuracy. This allows continuous tracking of promoter activity as cells change their growth rate from exponential to stationary phase in different media. We find a heavy-tailed distribution of promoter activities, with promoter activities spanning several orders of magnitude. While the shape of the distribution is almost completely independent of the growth conditions, the identity of the promoters expressed at different levels does depend on them. Translation machinery genes, however, keep the same relative expression levels in the distribution across conditions, and their fractional promoter activity tracks growth rate tightly. We present a simple optimization model for resource allocation which suggests that the observed invariant distributions might maximize growth rate. These invariant features of the distribution of promoter activities may suggest design constraints that shape the allocation of transcriptional resources.

  14. Molecular evolution of the Escherichia coli chromosome. IV. Sequence comparisons.

    Milkman, R; Bridges, M M

    1993-03-01

    DNA sequences have been compared in a 4,400-bp region for Escherichia coli K12 and 36 ECOR strains. Discontinuities in degree of similarity, previously inferred, are confirmed in detail. Three clonal frames are described on the basis of the present local high-resolution data, as well as previous analyses of restriction fragment length polymorphism (RFLP) and of multilocus enzyme electrophoresis (MLEE) covering small regions more widely dispersed on the chromosome. These three approaches show important consistency. The data illustrate the fact that, in the limited context of intraspecific genomic sequence variation, clonality and homology are synonymous. Two estimable quantitative properties are defined: recency of common ancestry (the reciprocal of the log10 of the number of generations since the most recent common ancestor), and the number of nucleotide pairs over which a given recency of common ancestry applies. In principle, these parameters are measures of the degree and physical extent of homology. The small size of apparent recombinational replacements, together with the observation that they occasionally occur in discontinuous series, raises the question of whether they result from the superimposition of replacements of much larger size (as expected from an elementary interpretation of conjugation and transduction in experimental E. coli systems) or via an alternative mechanism. Length polymorphisms of several sorts are described. PMID:8095913

  15. Increased cytoplasm viscosity hampers aggregate polar segregation in Escherichia coli.

    Oliveira, Samuel M D; Neeli-Venkata, Ramakanth; Goncalves, Nadia S M; Santinha, João A; Martins, Leonardo; Tran, Huy; Mäkelä, Jarno; Gupta, Abhishekh; Barandas, Marilia; Häkkinen, Antti; Lloyd-Price, Jason; Fonseca, José M; Ribeiro, Andre S

    2016-02-01

    In Escherichia coli, under optimal conditions, protein aggregates associated with cellular aging are excluded from midcell by the nucleoid. We study the functionality of this process under sub-optimal temperatures from population and time lapse images of individual cells and aggregates and nucleoids within. We show that, as temperature decreases, aggregates become homogeneously distributed and uncorrelated with nucleoid size and location. We present evidence that this is due to increased cytoplasm viscosity, which weakens the anisotropy in aggregate displacements at the nucleoid borders that is responsible for their preference for polar localisation. Next, we show that in plasmolysed cells, which have increased cytoplasm viscosity, aggregates are also not preferentially located at the poles. Finally, we show that the inability of cells with increased viscosity to exclude aggregates from midcell results in enhanced aggregate concentration in between the nucleoids in cells close to dividing. This weakens the asymmetries in aggregate numbers between sister cells of subsequent generations required for rejuvenating cell lineages. We conclude that the process of exclusion of protein aggregates from midcell is not immune to stress conditions affecting the cytoplasm viscosity. The findings contribute to our understanding of E. coli's internal organisation and functioning, and its fragility to stressful conditions. PMID:26507787

  16. Composite analysis for Escherichia coli at coastal beaches

    Bertke, E.E.

    2007-01-01

    At some coastal beaches, concentrations of fecal-indicator bacteria can differ substantially between multiple points at the same beach at the same time. Because of this spatial variability, the recreational water quality at beaches is sometimes determined by stratifying a beach into several areas and collecting a sample from each area to analyze for the concentration of fecal-indicator bacteria. The average concentration of bacteria from those points is often used to compare to the recreational standard for advisory postings. Alternatively, if funds are limited, a single sample is collected to represent the beach. Compositing the samples collected from each section of the beach may yield equally accurate data as averaging concentrations from multiple points, at a reduced cost. In the study described herein, water samples were collected at multiple points from three Lake Erie beaches and analyzed for Escherichia coli on modified mTEC agar (EPA Method 1603). From the multiple-point samples, a composite sample (n = 116) was formed at each beach by combining equal aliquots of well-mixed water from each point. Results from this study indicate that E. coli concentrations from the arithmetic average of multiple-point samples and from composited samples are not significantly different (t = 1.59, p = 0.1139) and yield similar measures of recreational water quality; additionally, composite samples could result in a significant cost savings.

  17. Light induced DEP for immobilizing and orienting Escherichia coli bacteria

    Miccio, Lisa; Marchesano, Valentina; Mugnano, Martina; Grilli, Simonetta; Ferraro, Pietro

    2016-01-01

    Manipulating bacteria and understanding their behavior when interacting with different substrates are of fundamental importance for patterning, detection, and any other topics related to health-care, food-enterprise, etc. Here, we adopt an innovative dielectrophoretic (DEP) approach based on electrode-free DEP for investigating smart but simple strategies for immobilization and orientation of bacteria. Escherichia coli DH5-alpha strain has been selected as subject of the study. The light induced DEP is achieved through ferroelectric iron-doped lithium niobate crystals used as substrates. Due to the photorefractive (PR) property of such material, suitable light patterns allow writing spatial-charges-distribution inside its volume and the resultant electric fields are able to immobilize E. coli on the surface. The experiments showed that, after laser irradiation, about 80% of bacteria is blocked and oriented along a particular direction on the crystals within an area of few square centimeters. The investigation presented here could open the way for detection or patterning applications based on a new driving mechanism. Future perspectives also include the possibility to actively switch by light the DEP forces, through the writing/erasing characteristic of PR fields, to dynamically control biofilm spatial structure and arrangement.

  18. Outbreaks of virulent diarrheagenic Escherichia coli - are we in control?

    Werber Dirk

    2012-02-01

    Full Text Available Abstract Shiga toxin-producing Escherichia coli (STEC are the most virulent diarrheagenic E. coli known to date. They can be spread with alarming ease via food as exemplified by a large sprout-borne outbreak of STEC O104:H4 in 2011 that was centered in northern Germany and affected several countries. Effective control of such outbreaks is an important public health task and necessitates early outbreak detection, fast identification of the outbreak vehicle and immediate removal of the suspected food from the market, flanked by consumer advice and measures to prevent secondary spread. In our view, opportunities to improve control of STEC outbreaks lie in early clinical suspicion for STEC infection, timely diagnosis of all STEC at the serotype-level and integrating molecular subtyping information into surveillance systems. Furthermore, conducting analytical studies that supplement patients' imperfect food history recall and performing, as an investigative element, product tracebacks, are pivotal but underutilized tools for successful epidemiologic identification of the suspected vehicle in foodborne outbreaks. As a corollary, these tools are amenable to tailor microbiological testing of suspected food. Please see related article: http://www.biomedcentral.com/1741-7015/10/12

  19. Efflux transporter engineering markedly improves amorphadiene production in Escherichia coli.

    Zhang, Congqiang; Chen, Xixian; Stephanopoulos, Gregory; Too, Heng-Phon

    2016-08-01

    Metabolic engineering aims at altering cellular metabolism to produce valuable products at high yields and titers. Achieving high titers and productivity can be challenging if final products are largely accumulated intracellularly. A potential solution to this problem is to facilitate the export of these substances from cells by membrane transporters. Amorphadiene, the precursor of antimalarial drug artemisinin, is known to be secreted from Escherichia coli overexpressing the biosynthetic pathway. In order to assess the involvement of various endogenous efflux pumps in amorphadiene transport, the effects of single gene deletion of 16 known multidrug-resistant membrane efflux transporters were examined. The outer membrane protein TolC was found to be intimately involved in amorphadiene efflux. The overexpression of tolC together with ABC family transporters (macAB) or MFS family transporters (emrAB or emrKY) enhanced amorphadiene titer by more than threefold. In addition, the overexpression of transporters in the lipopolysaccharide transport system (msbA, lptD, lptCABFG) was found to improve amorphadiene production. As efflux transporters often have a wide range of substrate specificity, the multiple families of transporters were co-expressed and synergistic benefits were observed in amorphadiene production. This strategy of screening and then rationally engineering transporters can be used to improve the production of other valuable compounds in E. coli. Biotechnol. Bioeng. 2016;113: 1755-1763. © 2016 Wiley Periodicals, Inc. PMID:26804325

  20. Improvements In Ethanologenic Escherichia Coli and Klebsiella Oxytoca

    Dr. David Nunn

    2010-09-30

    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.

  1. Subversion of Host Innate Immunity by Uropathogenic Escherichia coli.

    Olson, Patrick D; Hunstad, David A

    2016-01-01

    Uropathogenic Escherichia coli (UPEC) cause the majority of community-onset urinary tract infections (UTI) and represent a major etiologic agent of healthcare-associated UTI. Introduction of UPEC into the mammalian urinary tract evokes a well-described inflammatory response, comprising pro-inflammatory cytokines and chemokines as well as cellular elements (neutrophils and macrophages). In human UTI, this inflammatory response contributes to symptomatology and provides means for diagnosis by standard clinical testing. Early in acute cystitis, as demonstrated in murine models, UPEC gains access to an intracellular niche that protects a population of replicating bacteria from arriving phagocytes. To ensure the establishment of this protected niche, UPEC employ multiple strategies to attenuate and delay the initiation of host inflammatory components, including epithelial secretion of chemoattractants. Recent work has also revealed novel mechanisms by which UPEC blunts neutrophil migration across infected uroepithelium. Taken together, these attributes distinguish UPEC from commensal and nonpathogenic E. coli strains. This review highlights the unique immune evasion and suppression strategies of this bacterial pathogen and offers directions for further study; molecular understanding of these mechanisms will inform the development of adjunctive, anti-virulence therapeutics for UTI. PMID:26742078

  2. Structure of CFA/I fimbriae from enterotoxigenic Escherichia coli

    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

    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.

  3. Biosynthesis of fluorescent cyanobacterial allophycocyanin trimer in Escherichia coli.

    Liu, Shaofang; Chen, Yingjie; Lu, Yandu; Chen, Huaxin; Li, Fuchao; Qin, Song

    2010-08-01

    Allophycocyanin (APC), a cyanobacterial photosynthetic phycobiliprotein, functions in energy transfer as a light-harvesting protein. One of the prominent spectroscopic characteristics of APC is a strong red-shift in the absorption and emission maxima when monomers are assembled into a trimer. Previously, holo-APC alpha and beta subunits (holo-ApcA and ApcB) were successfully synthesized in Escherichia coli. In this study, both holo-subunits from Synechocystis sp. PCC 6803 were co-expressed in E. coli, and found to self-assemble into trimers. The recombinant APC trimer was purified by metal affinity and size-exclusion chromatography, and had a native structure identical to native APC, as determined by characteristic spectroscopic measurements, fluorescence quantum yield, tryptic digestion analysis, and molecular weight measurements. Combined with results from a study in which only the monomer was formed, our results indicate that bilin synthesis and the subsequent attachment to apo-subunits are important for the successful assembly of APC trimers. This is the first study to report on the assembly of recombinant ApcA and ApcB into a trimer with native structure. Our study provides a promising method for producing better fluorescent tags, as well as a method to facilitate the genetic analysis of APC trimer assembly and biological function. PMID:20607408

  4. Association between antimicrobial consumption and resistance in Escherichia coli.

    Bergman, Miika; Nyberg, Solja T; Huovinen, Pentti; Paakkari, Pirkko; Hakanen, Antti J

    2009-03-01

    During a 9-year study period from 1997 through 2005, the association between antimicrobial resistance rates in Escherichia coli and outpatient antimicrobial consumption was investigated in 20 hospital districts in Finland. A total of 754,293 E. coli isolates, mainly from urine samples, were tested for antimicrobial resistance in 26 clinical microbiology laboratories. The following antimicrobials were studied: ampicillin, amoxicillin-clavulanate, cephalosporins, fluoroquinolones, trimethoprim, trimethoprim-sulfamethoxazole, pivmecillinam, and nitrofurantoin. We applied a protocol used in earlier studies in which the level of antimicrobial consumption over 1 year was compared with the level of resistance in the next year. Statistically significant associations were found for nitrofurantoin use versus nitrofurantoin resistance (P < 0.0001), cephalosporin use versus nitrofurantoin resistance (P = 0.0293), amoxicillin use versus fluoroquinolone resistance (P = 0.0031), and fluoroquinolone use versus ampicillin resistance (P = 0.0046). Interestingly, we found only a few associations between resistance and antimicrobial consumption. The majority of the associations studied were not significant, including the association between fluoroquinolone use and fluoroquinolone resistance. PMID:19104012

  5. Scalable purification of Bacillus anthracis protective antigen from Escherichia coli.

    Gwinn, William; Zhang, Mei; Mon, Sandii; Sampey, Darryl; Zukauskas, David; Kassebaum, Corby; Zmuda, Jonathan F; Tsai, Amos; Laird, Michael W

    2006-01-01

    The anthrax toxin consists of three proteins, protective antigen (PA), lethal factor, and edema factor that are produced by the Gram-positive bacterium, Bacillus anthracis. Current vaccines against anthrax use PA as their primary component. In this study, we developed a scalable process to produce and purify multi-gram quantities of highly pure, recombinant PA (rPA) from Escherichia coli. The rPA protein was produced in a 50-L fermentor and purified to >99% purity using anion-exchange, hydrophobic interaction, and hydroxyapatite chromatography. The final yield of purified rPA from medium cell density fermentations resulted in approximately 2.7 g of rPA per kg of cell paste (approximately 270 mg/L) of highly pure, biologically active rPA protein. The results presented here exhibit the ability to generate multi-gram quantities of rPA from E. coli that may be used for the development of new anthrax vaccines and anthrax therapeutics. PMID:15935696

  6. Pattern Formation of Bacterial Colonies by Escherichia coli

    Tokita, Rie; Katoh, Takaki; Maeda, Yusuke; Wakita, Jun-ichi; Sano, Masaki; Matsuyama, Tohey; Matsushita, Mitsugu

    2009-07-01

    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.

  7. Secretion of Alpha-Hemolysin by Escherichia coli Disrupts Tight Junctions in Ulcerative Colitis Patients

    Mirsepasi-Lauridsen, Hengameh Chloé; Du, Zhengyu; Struve, Carsten; Charbon, Godefroid; Karczewski, Jurgen; Krogfelt, Karen Angeliki; Petersen, Andreas Munk; Wells, Jerry M

    2016-01-01

    Objectives: The potential of Escherichia coli (E. coli) isolated from inflammatory bowel disease (IBD) patients to damage the integrity of the intestinal epithelium was investigated. Methods: E. coli strains isolated from patients with ulcerative colitis (UC) and healthy controls were tested for virulence capacity by molecular techniques and cytotoxic assays and transepithelial electric resistance (TER). E. coli isolate p19A was selected, and deletion mutants were created for alpha-hemolysin ...

  8. The Association of Virulence Determinants of Uropathogenic Escherichia coli With Antibiotic Resistance

    Sara Asadi; Mohammad Kargar; Kavous Solhjoo; Akram Najafi; Sadegh Ghorbani-Dalini

    2014-01-01

    Background: The emergence of antimicrobial resistant strains of Escherichia coli has raised considerable interest in understanding the diversity and epidemiology of E. coli infections in humans. Virulence factors of E. coli determine the specific infections caused by this microorganism. Objectives: This study aimed to determine the prevalence of eight E. coli virulence factors and their association with antimicrobial resistance in bacteria isolated from patients with urinary tract infecti...

  9. Relative effects of bacterial and protozoan predators on survival of Escherichia coli in estuarine water samples.

    McCambridge, J; McMeekin, T A

    1980-01-01

    The relative effect of protozoan and bacterial predators on the survival of Escherichia coli in estuarine water samples was examined. Predacious protozoa exerted their major influence on E. coli destruction during the first 2 days of a 10-day-decline period. Inhibition of protozoa after day 2 had little effect on E. coli survival. Bacterial predators also contributed to E. coli destruction but in natural estuarine water samples were maintained at lower levels due to "grazing" by predacious pr...

  10. Involvement of Focal Adhesion Kinase in Escherichia coli Invasion of Human Brain Microvascular Endothelial Cells

    Reddy, Marpadga A; Wass, Carol A.; Kim, Kwang Sik; Schlaepfer, David D.; Prasadarao, Nemani V.

    2000-01-01

    Escherichia coli K1 traversal across the blood-brain barrier is an essential step in the pathogenesis of neonatal meningitis. We have previously shown that invasive E. coli promotes the actin rearrangement of brain microvascular endothelial cells (BMEC), which constitute a lining of the blood-brain barrier, for invasion. However, signal transduction mechanisms involved in E. coli invasion are not defined. In this report we show that tyrosine kinases play a major role in E. coli invasion of hu...

  11. A Survey for Escherichia coli Virulence Factors in Asymptomatic Free-Ranging Parrots

    André Becker Saidenberg; Neiva Maria Robaldo Guedes; Gláucia Helena Fernandes Seixas; Mariangela da Costa Allgayer; Erica Pacífico de Assis; Luis Fabio Silveira; Priscilla Anne Melville; Nilson Roberti Benites

    2012-01-01

    Parrots in captivity are frequently affected by Escherichia coli (E. coli) infections. The objective of this study was to collect information on the carrier state for E. coli pathotypes in asymptomatic free-ranging parrots. Cloacal swabs were collected from nestlings of Hyacinth, Lear’s macaws and Blue-fronted Amazon parrots and tested by polymerase chain reaction (PCR) for virulence factors commonly found in enteropathogenic, avian pathogenic, and uropathogenic E. coli strains. In total, 44 ...

  12. Production of pili, hemolysin and siderophores in the urinary isolates of Escherichia coli

    Marković Tatjana; Šmitran Aleksandra; Petković Miroslav

    2013-01-01

    Introduction. Escherichia coli (E. coli) are the most frequent cause of the urinary tract infections. Uropathogenic E. coli (UPEC) produce virulence factors which enable them to survive in the urinary tract and cause an infection. Objective. The objective of this study was to determine phenotype characterization of E. coli isolated from outpatients’ urine in the region of Banja Luka over three-year period. In line with the objective, the following research tasks were set up: determining...

  13. Vergleichende geno- und phänotypische Charakterisierung von Escherichia coli aus Menschen, Hausschweinen und Wildtieren

    Frömmel, Ulrike

    2014-01-01

    Escherichia (E.) coli ist als kommensales Bakterium ein wichtiger Bestandteil des Mikrobioms von Säugern, jedoch zudem der häufigste Infektionserreger des Menschen. Entsprechend des Infektionsortes werden intestinal (InPEC) und extraintestinal pathogene E. coli (ExPEC) unterschieden. Die Pathogenese von E. coli-Infektionen ist durch Virulenzfaktoren determiniert, welche von jeweils spezifischen virulenzassoziierten Genen (inVAGs und exVAGs) kodiert werden. Häufig werden exVAGs auch in E. coli...

  14. Detection and Characterization of Diarrheagenic Escherichia coli from Young Children in Hanoi, Vietnam

    Nguyen, Trung Vu; Le Van, Phung; Le Huy, Chinh; Gia, Khanh Nguyen; Weintraub, Andrej

    2005-01-01

    Diarrhea continues to be one of the most common causes of morbidity and mortality among infants and children in developing countries. Escherichia coli is an emerging agent among pathogens that cause diarrhea. The development of a highly applicable technique for the detection of different categories of diarrheagenic E. coli is important. We have used multiplex PCR by combining eight primer pairs specific for enteroaggregative E. coli (EAEC), enteroinvasive E. coli (EIEC), enterohemorrhagic E. ...

  15. Estimating Escherichia coli loads in streams based on various physical, chemical, and biological factors

    Dwivedi, Dipankar; Mohanty, Binayak P.; Lesikar, Bruce J.

    2013-01-01

    Microbes have been identified as a major contaminant of water resources. Escherichia coli (E. coli) is a commonly used indicator organism. It is well recognized that the fate of E. coli in surface water systems is governed by multiple physical, chemical, and biological factors. The aim of this work is to provide insight into the physical, chemical, and biological factors along with their interactions that are critical in the estimation of E. coli loads in surface streams. There are various mo...

  16. Biosynthesis of odd-chain fatty alcohols in Escherichia coli.

    Cao, Ying-Xiu; Xiao, Wen-Hai; Liu, Duo; Zhang, Jin-Lai; Ding, Ming-Zhu; Yuan, Ying-Jin

    2015-05-01

    Engineered microbes offer the opportunity to design and implement artificial molecular pathways for renewable production of tailored chemical commodities. Targeted biosynthesis of odd-chain fatty alcohols is very challenging in microbe, due to the specificity of fatty acids synthase for two-carbon unit elongation. Here, we developed a novel strategy to directly tailor carbon number in fatty aldehydes formation step by incorporating α-dioxygenase (αDOX) from Oryza sativa (rice) into Escherichia coli αDOX oxidizes Cn fatty acids (even-chain) to form Cn-1 fatty aldehydes (odd-chain). Through combining αDOX with fatty acyl-acyl carrier protein (-ACP) thioesterase (TE) and aldehyde reductase (AHR), the medium odd-chain fatty alcohols profile (C11, C13, C15) was firstly established in E. coli. Also, medium even-chain alkanes (C12, C14) were obtained by substitution of AHR to aldehyde decarbonylase (AD). The titer of odd-chain fatty alcohols was improved from 7.4mg/L to 101.5mg/L in tube cultivation by means of fine-tuning endogenous fatty acyl-ACP TE (TesA'), αDOX, AHRs and the genes involved in fatty acids metabolism pathway. Through high cell density fed-batch fermentation, a titer of 1.95g/L odd-chain fatty alcohols was achieved, which was the highest reported titer in E. coli. Our system has greatly expanded the current microbial fatty alcohols profile that provides a new brand solution for producing complex and desired molecules in microbes. PMID:25773521

  17. Inhibition of Escherichia coli ATP synthase by amphibian antimicrobial peptides.

    Laughlin, Thomas F; Ahmad, Zulfiqar

    2010-04-01

    Previously melittin, the alpha-helical basic honey bee venom peptide, was shown to inhibit F(1)-ATPase by binding at the beta-subunit DELSEED motif of F(1)F(o)-ATP synthase. Herein, we present the inhibitory effects of the basic alpha-helical amphibian antimicrobial peptides, ascaphin-8, aurein 2.2, aurein 2.3, carein 1.8, carein 1.9, citropin 1.1, dermaseptin, maculatin 1.1, maganin II, MRP, or XT-7, on purified F(1) and membrane bound F(1)F(0)Escherichia coli ATP synthase. We found that the extent of inhibition by amphibian peptides is variable. Whereas MRP-amide inhibited ATPase essentially completely (approximately 96% inhibition), carein 1.8 did not inhibit at all (0% inhibition). Inhibition by other peptides was partial with a range of approximately 13-70%. MRP-amide was also the most potent inhibitor on molar scale (IC(50) approximately 3.25 microM). Presence of an amide group at the c-terminal of peptides was found to be critical in exerting potent inhibition of ATP synthase ( approximately 20-40% additional inhibition). Inhibition was fully reversible and found to be identical in both F(1)F(0) membrane preparations as well as in isolated purified F(1). Interestingly, growth of E. coli was abrogated in the presence of ascaphin-8, aurein 2.2, aurein 2.3, citropin 1.1, dermaseptin, magainin II-amide, MRP, MRP-amide, melittin, or melittin-amide but was unaffected in the presence of carein 1.8, carein 1.9, maculatin 1.1, magainin II, or XT-7. Hence inhibition of F(1)-ATPase and E. coli cell growth by amphibian antimicrobial peptides suggests that their antimicrobial/anticancer properties are in part linked to their actions on ATP synthase. PMID:20100509

  18. Probiotic Escherichia coli Nissle 1917 reduces growth, Shiga toxin expression, release and thus cytotoxicity of enterohemorrhagic Escherichia coli.

    Mohsin, Mashkoor; Guenther, Sebastian; Schierack, Peter; Tedin, Karsten; Wieler, Lothar H

    2015-01-01

    Due to increased release or production of Shiga toxin by Enterohemorrhagic Escherichia coli (EHEC) after exposure to antimicrobial agents, the role of antimicrobial agents in EHEC mediated infections remains controversial. Probiotics are therefore rapidly gaining interest as an alternate therapeutic option. The well-known probiotic strain Escherichia coli Nissle 1917 (EcN) was tested in vitro to determine its probiotic effects on growth, Shiga toxin (Stx) gene expression, Stx amount and associated cytotoxicity on the most important EHEC strains of serotype O104:H4 and O157:H7. Following co-culture of EcN:EHEC in broth for 4 and 24 h, the probiotic effects on EHEC growth, toxin gene expression, Stx amount and cytotoxicity were determined using quantitative real time-PCR, Stx-ELISA and Vero cytotoxicity assays. Probiotic EcN strongly reduced EHEC numbers (cfu) of O104:H4 up to (68%) and O157:H7 to (72.2%) (pcoli strain MG1655 had no effect on EHEC growth. The level of stx expression was significantly down-regulated, particularly for the stx2a gene. The stx down-regulation in EcN co-culture was not due to reduced numbers of EHEC. A significant inhibition in Stx amounts and cytotoxicity were also observed in sterile supernatants of EcN:EHEC co-cultures. These findings indicate that probiotic EcN displays strong inhibitory effects on growth, Shiga toxin gene expression, amount and cytotoxicity of EHEC strains. Thus, EcN may be considered as a putative therapeutic candidate, in particular against EHEC O104:H4 and O157:H7. PMID:25465158

  19. Brote causado por Escherichia coli en Chalco, México Outbreak caused by Escherichia coli in Chalco, México

    Iliana Alejandra Cortés-Ortiz

    2002-07-01

    Full Text Available Objetivo. Identificar el agente causal del brote de diarrea asociado con el desbordamiento del canal de aguas negras en Chalco. Material y métodos. Estudio retrospectivo y transversal, efectuado en el Instituto de Diagnóstico y Referencia Epidemiológicos (InDRE, de la Secretaría de Salud, con 1 550 hisopos rectales para el aislamiento e identificación bioquímica de V. cholerae y enterobacterias, obtenidos de la población del Valle de Chalco, que presentó diarrea y vómito durante el desastre natural acontecido el 31 de mayo de 2000. El análisis de los resultados se efectuó por la diferencia entre las proporciones de dos poblaciones (prueba de Ji cuadrada. Las cepas de E. coli se hibridaron por "colony blot" para los grupos ETEC, EIEC, EPEC y EHEC. Resultados. El 0.45% correspondió a Salmonella: S. agona, S. infantis, S. enteritidis, S. muenchen, S. typhimurium; 0.06% a Shigella flexneri 3a, y 76.6% a E. coli: 62.2% a ETEC (44.6 % con LT, 11.2% con ST, y 44.1% con ambas sondas, 0.84% a EIEC (sonda ial, 0.84% a EPEC (sonda bundle-forming pilus BFP, 0.08% a E. coli enterohemorrágica no-O157:H7 (sonda pCVD419, y 36.02% no hibridó. No se encontró asociación entre E. coli patógena con la edad y género. Conclusiones. Escherichia coli podría ser responsable del brote de diarrea. Es importante conocer el agente etiológico del brote para encaminar las estrategias en el estudio y control sanitario del mismo.Objective. To identify the etiologic agent responsible for a disease outbreak following an overflow of sewage water in Valle de Chalco, Mexico. Material and Methods. A retrospective cross-sectional study was carried out. Rectal samples were collected from the population of Chalco valley, who suffered from diarrhea and vomiting during a natural disaster that took place on May 31, 2000. The Instituto de Diagnóstico y Referencia Epidemiológicos (Epidemic Reference and Diagnosis Institute, InDRE, Ministry of Health, received 1521 rectal

  20. An Optimized Medium for Screening of L-Asparaginase production by Escherichia coli

    Younes Ghasemi

    2008-01-01

    Full Text Available Purified L-asparaginase II from Escherichia coli has been supplied and employed in the acute leukemia and other malignant neoplasms chemotherapy. L-asparaginase II gene (ansB in E. coli is under regulation and certain conditions is needed for expression of this gene. In this investigation ,the various concentrations of modified M9 medium ingredients and various carbon source were tested to optimize the medium for expression and identification of L-asparaginase in E. coli. Finally a semi-quantitative plate assay for L-asparaginase producing Escherichia coli is reported.

  1. Hygiene Sanitasi Pengolahan Makanan Dan Pemeriksaan Escherichia Coli (E.Coli) Pada Pecel Yang Dijual Di Pasar Petisah Tahun 2015

    Lubis, Nur Hasanah

    2015-01-01

    Pecel is a fast food consist of boiled vegetables and served with peanut chili sauce as a mixture. The seller is used prepare and serve pecel with hands directy. It causes pecel have a hazard contamination by bacteria Escherichia Coli (E.coli). E.coli presence in source water or food is definitely an indication of human fecal contamination and the presence of E.coli shows a sign which is not good sanitation practices to water and food. The objective of this research is to know about hygien...

  2. The Antibiotic Susceptibility Patterns of Uropathogenic Escherichia Coli, With Special Reference to the Fluoroquinolones

    Shariff V A, Abdul Rahaman; Shenoy M, Suchitra; Yadav, Taruna; M, Radhakrishna

    2013-01-01

    Context: The emergence of drug resistance to trimethoprim-sulfamethoxazole, the penicillins, cephalosporins, and fluoroquinolones by Uropathogenic Escherichia coli (UPEC) has limited the options for selecting the appropriate antibiotic for the treatment of urinary tract infections.

  3. SIMULTANEOUS EFFECTS OF SHAKING AND TEMPERATURE ON VEROTOXIN1 PHAGE INDUCTION FROM VEROTOXIGENIC ESCHERICHIA COLI STRAINS

    H. Hosain Zadegan, M. Sattari, M. H. Zahir, A. A. Allame

    2006-01-01

    Full Text Available Induction of lambda phage carring verotoxin1 gene from a verotoxigenic strains of Escherichia coli and released verotoxin1 were studied under environmental factors of shaking and termperature. Verotoxin1 phage in Escherichia coli PA 101 and transductants was confirmed by bacteriophage detection assay. Shaking of culture media and increasing temperature until 42 ºC increased phage particles in supernatants of Escherichia coli PA 101. Our results indicate that environmental factors such as shaking movements in natural inhabitates of bacteria such as river or sewage streams and temperature rise in summer season could be factors in induce and release free verotoxin1 – producing phage particles in nature that in turn could be the source of phage spreading to other related bacteria , and responsible for increased outbreaks of food borne diseases with verotoxigenic Escherichia coli in warm monthes of year in tropical areas.

  4. Shigella toxin inhibition of binding and translation of polyuridylic acid by Escherichia coli ribosomes.

    Olenick, J G; Wolfe, A D

    1980-01-01

    Shigella toxin inhibits polyuridylic acid-directed polymerization of phenylalanine in ribosome-enzyme systems obtained from Escherichia coli or from Shigella dysenteriae. The inhibition is the result of toxin acting on ribosomes to prevent polyuridylic acid attachment.

  5. Differential decay of Enterococci and Escherichia coli originating from two fecal pollution sources

    Using in situ subtropical aquatic mesocosms, fecal source (cattle manure versus sewage) was shown to be the most important contributor to differential loss in viability of fecal indicator bacteria (FIB), specifically enterococci in freshwater and Escherichia coli in marine habita...

  6. Selection of unique Escherichia coli clones by random amplified polymorphic DNA (RAPD)

    Nielsen, Karen L; Godfrey, Paul A; Stegger, Marc;

    2014-01-01

    Identifying and characterizing clonal diversity are important when analysing fecal flora. We evaluated random amplified polymorphic DNA (RAPD) PCR, applied for selection of Escherichia coli isolates, by whole genome sequencing. RAPD was fast, and reproducible as screening method for selection...

  7. Prevalence of Antibiotic Resistance in Escherichia coli Isolated from Poultry Meat Supply in Isfahan

    Farhad Safarpordehkordi; Emad Yahaghi; Ebrahim Khodaverdi Darian

    2014-01-01

    Background and Aim: Unfortunately, conventional antibiotic therapies which were used for cases of food poisoning caused by Escherichia coli are costly and ineffective. This study was carried out in order to detection and investigates the antibiotic resistance pattern of Escherichia coli isolated from chicken meat distributed in Isfahan province. Materials and Methods: 220 chicken meat samples were collected from shopping centers in Isfahan province. Samples were initially cultured and geno...

  8. Isolation of Shiga toxin-producing Escherichia coli from raw milk in Kermanshah, Iran

    Pantea Mohammadi; Ramin Abiri; Mansour Rezaei; Siavosh Salmanzadeh-Ahrabi

    2013-01-01

    Background and Objectives Infectious diarrhoeal diseases are great problem throughout the world and are responsible for considerable morbidity and mortality. Shiga toxin-producing Escherichia coli (STEC) is a major cause of gastroenteritis that may be complicated by hemorrhagic colitis (HC) or the hemolytic uremic syndrome (HUS), which is the main cause of acute renal failure in children. Food-borne outbreaks associated with Shiga toxin-producing Escherichia coli have been well documented wor...

  9. BIOAKTIFITAS MINYAK ATSIRI SEREH Cymbopogon citratus DC. TERHADAP PERTUMBUHAN BAKTERI Escherichia coli DAN Staphylococcus aureus

    Rahman, Hasriani

    2013-01-01

    Penelitian ini mengenai bioaktifitas minyak atsiri sereh Cymbopogon citratus DC. terhadap pertumbuhan bakteri Escherichia coli dan Staphylococcus aureus. Penelitian ini bertujuan untuk mengetahui bioaktifitas dan sifat antibakteri minyak atsiri sereh Cymbopogon citratus DC. terhadap pertumbuhan bakteri Escherichia coli dan Staphylococcus aureus. Pengujian daya hambat dilakukan dengan metode difusi agar menggunakan 5 variasi konsentrasi 100%, 50%, 25%, 12,5% dan 6,25% b/v pada media MHA (Mull...

  10. Genome Sequences of Two Copper-Resistant Escherichia coli Strains Isolated from Copper-Fed Pigs

    Lüthje, Freja L.; Hasman, Henrik; Aarestrup, Frank Møller; Alwathnani, Hend A.; Rensing, Christopher

    2014-01-01

    The draft genome sequences of two copper-resistant Escherichia coli strains were determined. These had been isolated from copper-fed pigs and contained additional putative operons conferring copper and other metal and metalloid resistances.......The draft genome sequences of two copper-resistant Escherichia coli strains were determined. These had been isolated from copper-fed pigs and contained additional putative operons conferring copper and other metal and metalloid resistances....

  11. Antibacterial activity of natural spices on multiple drug resistant Escherichia coli isolated from drinking water, Bangladesh

    Rahman, Shahedur; Parvez, Anowar Khasru; Islam, Rezuanul; Khan, Mahboob Hossain

    2011-01-01

    Background Spices traditionally have been used as coloring agents, flavoring agents, preservatives, food additives and medicine in Bangladesh. The present work aimed to find out the antimicrobial activity of natural spices on multi-drug resistant Escherichia coli isolates. Methods Anti-bacterial potentials of six crude plant extracts (Allium sativum, Zingiber officinale, Allium cepa, Coriandrum sativum, Piper nigrum and Citrus aurantifolia) were tested against five Escherichia coli isolated f...

  12. Antimicrobial-resistant faecal Escherichia coli in wild mammals in central Europe: multiresistant Escherichia coli producing extended-spectrum ß-lactamases in wild boars

    Literak, I.; Dolejska, Monika; Radimersky, T.;

    2010-01-01

    Aims: To determine the presence of antibiotic-resistant faecal Escherichia coli in populations of wild mammals in the Czech Republic and Slovakia. Methods and Results: Rectal swabs or faeces collected during 2006-2008 from wild mammals were spread on MacConkey agar and MacConkey agar containing 2...... mg l-1 of cefotaxime. From plates with positive growth, one isolate was recovered and identified as E. coli. Susceptibility to 12 antibiotics was tested using the disk diffusion method. Resistance genes, class 1 and 2 integrons and gene cassettes were detected in resistant isolates by polymerase...... prevalence of resistant isolates was 2% in small terrestrial mammals (rodents and insectivores, n(E. coli) = 242), 12% in wild ruminants and foxes (n(E. coli) = 42), while no resistant isolates were detected in brown bears (n(E. coli) = 16). In wild boars (Sus scrofa) (n(E. coli) = 290), the prevalence of...

  13. Stimulation of Escherichia coli F-18Col- Type-1 fimbriae synthesis by leuX

    Newman, Joseph V.; Burghoff, Robert L.; Pallesen, Lars;

    1994-01-01

    Escherichia coli F-18, a normal human fecal isolate, is an excellent colonizer of the streptomycin-treated mouse large intestine. E. coli F-18Col-, a derivative of E. coli F-18 which no longer makes the E. coli F-18 colicin, colonizes the large intestine as well as E. coli F-18 when fed to mice...... alone but is eliminated when fed together with E. coli F-18. Recently we randomly cloned E. coli F-18 DNA into E. coli F-18Col- and let the mouse intestine select the best colonizer. In this way, we isolated a 6.5-kb E. coli F-18 DNA sequence that simultaneously stimulated synthesis of type 1 fimbriae...

  14. CRISPR Content Correlates with the Pathogenic Potential of Escherichia coli.

    Enriqueta García-Gutiérrez

    Full Text Available Guide RNA molecules (crRNA produced from clustered regularly interspaced short palindromic repeat (CRISPR arrays, altogether with effector proteins (Cas encoded by cognate cas (CRISPR associated genes, mount an interference mechanism (CRISPR-Cas that limits acquisition of foreign DNA in Bacteria and Archaea. The specificity of this action is provided by the repeat intervening spacer carried in the crRNA, which upon hybridization with complementary sequences enables their degradation by a Cas endonuclease. Moreover, CRISPR arrays are dynamic landscapes that may gain new spacers from infecting elements or lose them for example during genome replication. Thus, the spacer content of a strain determines the diversity of sequences that can be targeted by the corresponding CRISPR-Cas system reflecting its functionality. Most Escherichia coli strains possess either type I-E or I-F CRISPR-Cas systems. To evaluate their impact on the pathogenicity of the species, we inferred the pathotype and pathogenic potential of 126 strains of this and other closely related species and analyzed their repeat content. Our results revealed a negative correlation between the number of I-E CRISPR units in this system and the presence of pathogenicity traits: the median number of repeats was 2.5-fold higher for commensal isolates (with 29.5 units, range 0-53 than for pathogenic ones (12.0, range 0-42. Moreover, the higher the number of virulence factors within a strain, the lower the repeat content. Additionally, pathogenic strains of distinct ecological niches (i.e., intestinal or extraintestinal differ in repeat counts. Altogether, these findings support an evolutionary connection between CRISPR and pathogenicity in E. coli.

  15. A domain sequence approach to pangenomics: applications to Escherichia coli.

    Snipen, Lars-Gustav; Ussery, David W

    2012-01-01

    The study of microbial pangenomes relies on the computation of gene families, i.e. the clustering of coding sequences into groups of essentially similar genes. There is no standard approach to obtain such gene families. Ideally, the gene family computations should be robust against errors in the annotation of genes in various genomes. In an attempt to achieve this robustness, we propose to cluster sequences by their domain sequence, i.e. the ordered sequence of domains in their protein sequence. In a study of 347 genomes from Escherichia coli we find on average around 4500 proteins having hits in Pfam-A in every genome, clustering into around 2500 distinct domain sequence families in each genome. Across all genomes we find a total of 5724 such families. A binomial mixture model approach indicates this is around 95% of all domain sequences we would expect to see in E. coli in the future. A Heaps law analysis indicates the population of domain sequences is larger, but this analysis is also very sensitive to smaller changes in the computation procedure. The resolution between strains is good despite the coarse grouping obtained by domain sequence families. Clustering sequences by their ordered domain content give us domain sequence families, who are robust to errors in the gene prediction step. The computational load of the procedure scales linearly with the number of genomes, which is needed for the future explosion in the number of re-sequenced strains. The use of domain sequence families for a functional classification of strains clearly has some potential to be explored. PMID:24555018

  16. Vanillin production by recombinant strains of Escherichia coli Produção de vanilina por linhagens recombinantes de Escherichia coli

    Attilio Converti; Danilo de Faveri; Patrizia Perego; Paolo Barghini; Maurizio Ruzzi; Luciane Sene

    2003-01-01

    Vanillin production from ferulate was studied using different recombinant strains of Escherichia coli. To prevent the occurrence of aerobic conditions and then possible product oxidation, tests were performed in Erlenmeyer flasks under mild mixing (150 rpm). Among other transformants, E. coli JM109(pBB1) appeared to be the best vanillin producer, being able to convert no less than 95% of starting ferulate to the product within 1h. This yield decreased down to 72% after 72h, likely because of ...

  17. Prevalence and geographical distribution of Escherichia coli O157 in India: a 10-year survey.

    Sehgal, Rakesh; Kumar, Yashwant; Kumar, Sunil

    2008-04-01

    Escherichia coli colonizes the human gastrointestinal tract and produces a variety of diseases. Escherichia coli O157 is one of the most important pathogenic strains reported from food-borne illnesses leading to enterohemorrhagic colitis. The National Salmonella and Escherichia Centre is a national reference centre for Salmonella and Escherichia for India; it receives samples from research laboratories, hospitals and institutions for serological identification. The present study is an epidemiological survey of E. coli O157 in different regions of India. The data are based on samples received from humans, food items, animals and the environment. A total of 17 093 isolates cultured from samples were received during the 10-year period of which 5678 were from human sources. Thirty (0.5%) human samples were positive for E. coli O157. A significantly high percentage of E. coli O157 were isolated from meat (0.9%, 13/1376), milk and milk products (1.8%, 10/553), seafood (8.4%, 16/190) and water (1.6%, 8/486). The isolates were found to be distributed among domestic and wild animals, and the maximum number of isolates of E. coli O157 was detected in samples received from coastal belt areas. Escherichia coli O157 is widely distributed among humans and animals, food and environment in different geographical regions of India. PMID:18321544

  18. Molecular Cloning of Genes for Cellobiose Utilization and Their Expression in Escherichia coli

    Armentrout, Richard W.; Brown, Ronald D.

    1981-01-01

    The genes for cellobiose utilization in Escherichia adecarboxylata were cloned by using recombinant deoxyribonucleic acid techniques and transferred to Escherichia coli. Preliminary analysis of the β-glucosidase activity expressed in these host cells indicated that the enzyme is membrane bound and required magnesium ions, phosphate ions, and heat-stable, non-dialyzable factors from the bacterial cytoplasm.

  19. Functional genomics by NMR spectroscopy. Phenylacetate catabolism in Escherichia coli.

    Ismail, Wael; El-Said Mohamed, Magdy; Wanner, Barry L; Datsenko, Kirill A; Eisenreich, Wolfgang; Rohdich, Felix; Bacher, Adelbert; Fuchs, Georg

    2003-07-01

    Aerobic metabolism of phenylalanine in most bacteria proceeds via oxidation to phenylacetate. Surprisingly, the further metabolism of phenylacetate has not been elucidated, even in well studied bacteria such as Escherichia coli. The only committed step is the conversion of phenylacetate into phenylacetyl-CoA. The paa operon of E. coli encodes 14 polypeptides involved in the catabolism of phenylacetate. We have found that E. coli K12 mutants with a deletion of the paaF, paaG, paaH, paaJ or paaZ gene are unable to grow with phenylacetate as carbon source. Incubation of a paaG mutant with [U-13C8]phenylacetate yielded ring-1,2-dihydroxy-1,2-dihydrophenylacetyl lactone as shown by NMR spectroscopy. Incubation of the paaF and paaH mutants with phenylacetate yielded delta3-dehydroadipate and 3-hydroxyadipate, respectively. The origin of the carbon atoms of these C6 compounds from the aromatic ring was shown using [ring-13C6]phenylacetate. The paaG and paaZ mutants also converted phenylacetate into ortho-hydroxyphenylacetate, which was previously identified as a dead end product of phenylacetate catabolism. These data, in conjunction with protein sequence data, suggest a novel catabolic pathway via CoA thioesters. According to this, phenylacetyl-CoA is attacked by a ring-oxygenase/reductase (PaaABCDE proteins), generating a hydroxylated and reduced derivative of phenylacetyl-CoA, which is not re-oxidized to a dihydroxylated aromatic intermediate, as in other known aromatic pathways. Rather, it is proposed that this nonaromatic intermediate CoA ester is further metabolized in a complex reaction sequence comprising enoyl-CoA isomerization/hydration, nonoxygenolytic ring opening, and dehydrogenation catalyzed by the PaaG and PaaZ proteins. The subsequent beta-oxidation-type degradation of the resulting CoA dicarboxylate via beta-ketoadipyl-CoA to succinyl-CoA and acetyl-CoA appears to be catalyzed by the PaaJ, PaaF and PaaH proteins. PMID:12846838

  20. Overexpression of Peanut Diacylglycerol Acyltransferase 2 in Escherichia coli

    Yang, Lianqun; Zhang, Bin; Chen, Gao; Bi, Yuping

    2013-01-01

    Diacylglycerol acyltransferase (DGAT) is the rate-limiting enzyme in triacylglycerol biosynthesis in eukaryotic organisms. Triacylglycerols are important energy-storage oils in plants such as peanuts, soybeans and rape. In this study, Arachis hypogaea type 2 DGAT (AhDGAT2) genes were cloned from the peanut cultivar ‘Luhua 14’ using a homologous gene sequence method and rapid amplification of cDNA ends. To understand the role of AhDGAT2 in triacylglycerol biosynthesis, two AhDGAT2 nucleotide sequences that differed by three amino acids were expressed as glutathione S-transferase (GST) fusion proteins in Escherichia coli Rosetta (DE3). Following IPTG induction, the isozymes (AhDGAT2a and AhDGAT2b) were expressed as 64.5 kDa GST fusion proteins. Both AhDGAT2a and AhDGAT2b occurred in the host cell cytoplasm and inclusion bodies, with larger amounts in the inclusion bodies. Overexpression of AhDGATs depressed the host cell growth rates relative to non-transformed cells, but cells harboring empty-vector, AhDGAT2a–GST, or AhDGAT2b–GST exhibited no obvious growth rate differences. Interestingly, induction of AhDGAT2a–GST and AhDGAT2b–GST proteins increased the sizes of the host cells by 2.4–2.5 times that of the controls (post-IPTG induction). The total fatty acid (FA) levels of the AhDGAT2a–GST and AhDGAT2a–GST transformants, as well as levels of C12:0, C14:0, C16:0, C16:1, C18:1n9c and C18:3n3 FAs, increased markedly, whereas C15:0 and C21:0 levels were lower than in non-transformed cells or those containing empty-vectors. In addition, the levels of some FAs differed between the two transformant strains, indicating that the two isozymes might have different functions in peanuts. This is the first time that a full-length recombinant peanut DGAT2 has been produced in a bacterial expression system and the first analysis of its effects on the content and composition of fatty acids in E. coli. Our results indicate that AhDGAT2 is a strong candidate gene for

  1. Overexpression of peanut diacylglycerol acyltransferase 2 in Escherichia coli.

    Zhenying Peng

    Full Text Available Diacylglycerol acyltransferase (DGAT is the rate-limiting enzyme in triacylglycerol biosynthesis in eukaryotic organisms. Triacylglycerols are important energy-storage oils in plants such as peanuts, soybeans and rape. In this study, Arachis hypogaea type 2 DGAT (AhDGAT2 genes were cloned from the peanut cultivar 'Luhua 14' using a homologous gene sequence method and rapid amplification of cDNA ends. To understand the role of AhDGAT2 in triacylglycerol biosynthesis, two AhDGAT2 nucleotide sequences that differed by three amino acids were expressed as glutathione S-transferase (GST fusion proteins in Escherichia coli Rosetta (DE3. Following IPTG induction, the isozymes (AhDGAT2a and AhDGAT2b were expressed as 64.5 kDa GST fusion proteins. Both AhDGAT2a and AhDGAT2b occurred in the host cell cytoplasm and inclusion bodies, with larger amounts in the inclusion bodies. Overexpression of AhDGATs depressed the host cell growth rates relative to non-transformed cells, but cells harboring empty-vector, AhDGAT2a-GST, or AhDGAT2b-GST exhibited no obvious growth rate differences. Interestingly, induction of AhDGAT2a-GST and AhDGAT2b-GST proteins increased the sizes of the host cells by 2.4-2.5 times that of the controls (post-IPTG induction. The total fatty acid (FA levels of the AhDGAT2a-GST and AhDGAT2a-GST transformants, as well as levels of C12:0, C14:0, C16:0, C16:1, C18:1n9c and C18:3n3 FAs, increased markedly, whereas C15:0 and C21:0 levels were lower than in non-transformed cells or those containing empty-vectors. In addition, the levels of some FAs differed between the two transformant strains, indicating that the two isozymes might have different functions in peanuts. This is the first time that a full-length recombinant peanut DGAT2 has been produced in a bacterial expression system and the first analysis of its effects on the content and composition of fatty acids in E. coli. Our results indicate that AhDGAT2 is a strong candidate gene for

  2. Production of extracellular fatty acid using engineered Escherichia coli

    Liu Hui

    2012-04-01

    Full Text Available Abstract Background As an alternative for economic biodiesel production, the microbial production of extracellular fatty acid from renewable resources is receiving more concerns recently, since the separation of fatty acid from microorganism cells is normally involved in a series of energy-intensive steps. Many attempts have been made to construct fatty acid producing strains by targeting genes in the fatty acid biosynthetic pathway, while few studies focused on the cultivation process and the mass transfer kinetics. Results In this study, both strain improvements and cultivation process strategies were applied to increase extracellular fatty acid production by engineered Escherichia coli. Our results showed overexpressing ‘TesA and the deletion of fadL in E. coli BL21 (DE3 improved extracellular fatty acid production, while deletion of fadD didn’t strengthen the extracellular fatty acid production for an undetermined mechanism. Moreover, the cultivation process controls contributed greatly to extracellular fatty acid production with respect to titer, cell growth and productivity by adjusting the temperature, adding ampicillin and employing on-line extraction. Under optimal conditions, the E. coli strain (pACY-‘tesA-ΔfadL produced 4.8 g L−1 extracellular fatty acid, with the specific productivity of 0.02 g h−1 g−1dry cell mass, and the yield of 4.4% on glucose, while the ratios of cell-associated fatty acid versus extracellular fatty acid were kept below 0.5 after 15 h of cultivation. The fatty acids included C12:1, C12:0, C14:1, C14:0, C16:1, C16:0, C18:1, C18:0. The composition was dominated by C14 and C16 saturated and unsaturated fatty acids. Using the strain pACY-‘tesA, similar results appeared under the same culture conditions and the titer was also much higher than that ever reported previously, which suggested that the supposedly superior strain did not necessarily perform best for the efficient production of desired

  3. Protein abundance profiling of the Escherichia coli cytosol

    Mann Matthias

    2008-02-01

    Full Text Available Abstract Background Knowledge about the abundance of molecular components is an important prerequisite for building quantitative predictive models of cellular behavior. Proteins are central components of these models, since they carry out most of the fundamental processes in the cell. Thus far, protein concentrations have been difficult to measure on a large scale, but proteomic technologies have now advanced to a stage where this information becomes readily accessible. Results Here, we describe an experimental scheme to maximize the coverage of proteins identified by mass spectrometry of a complex biological sample. Using a combination of LC-MS/MS approaches with protein and peptide fractionation steps we identified 1103 proteins from the cytosolic fraction of the Escherichia coli strain MC4100. A measure of abundance is presented for each of the identified proteins, based on the recently developed emPAI approach which takes into account the number of sequenced peptides per protein. The values of abundance are within a broad range and accurately reflect independently measured copy numbers per cell. As expected, the most abundant proteins were those involved in protein synthesis, most notably ribosomal proteins. Proteins involved in energy metabolism as well as those with binding function were also found in high copy number while proteins annotated with the terms metabolism, transcription, transport, and cellular organization were rare. The barrel-sandwich fold was found to be the structural fold with the highest abundance. Highly abundant proteins are predicted to be less prone to aggregation based on their length, pI values, and occurrence patterns of hydrophobic stretches. We also find that abundant proteins tend to be predominantly essential. Additionally we observe a significant correlation between protein and mRNA abundance in E. coli cells. Conclusion Abundance measurements for more than 1000 E. coli proteins presented in this work

  4. Clonal relationships among bloodstream isolates of Escherichia coli.

    Maslow, J N; Whittam, T S; Gilks, C F; Wilson, R A; Mulligan, M E; Adams, K S; Arbeit, R D

    1995-01-01

    The clonal relationships among 187 bloodstream isolates of Escherichia coli from 179 patients at Boston, Mass., Long Beach, Calif., and Nairobi, Kenya, were determined by multilocus enzyme electrophoresis (MLEE), analysis of polymorphisms associated with the ribosomal operon (ribotyping), and serotyping. MLEE based on 20 enzymes resolved 101 electrophoretic types (ETs), forming five clusters; ribotyping resolved 56 distinct patterns concordant with the analysis by MLEE. The isolates at each study site formed a genetically diverse group and demonstrated similar clonal structures, with the same small subset of lineages accounting for the majority of isolates at each site. Moreover, two ribotypes accounted for approximately 30% of the isolates at each study site. One cluster contained the majority (65%) of isolates and, by direct comparison of the ETs and ribotypes of individual isolates, was genetically indistinguishable from the largest cluster for each of two other collections of E. coli causing pyelonephritis and neonatal meningitis (R. K. Selander, T. K. Korhonen, V. Väisänen-Rhen, P. H. Williams, P. E. Pattison, and D. A. Caugent, Infect. Immun. 52:213-222, 1986; M. Arthur, C. E. Johnson, R. H. Rubin, R. D. Arbeit, C. Campanelli, C. Kim, S. Steinbach, M. Agarwal, R. Wilkinson, and R. Goldstein, Infect. Immun. 57:303-313, 1989), thus defining a virulent set of lineages. The isolates within these virulent lineages typically carried DNA homologous to the adhesin operon pap or sfa and the hemolysin operon hly and expressed O1, O2, O4, O6, O18, O25, or O75 antigens. DNA homologous to pap was distributed among isolates of each major cluster, whereas hly was restricted to isolates of two clusters, typically detected in pap-positive strains, and sfa was restricted to isolates of one cluster, typically detected in pap- and hly-positive strains. The occurrence of pap-positive isolates in the same geographically and genetically divergent lineages suggests that this

  5. Inducible Escherichia coli fermentation for increased plasmid DNA production.

    Carnes, Aaron E; Hodgson, Clague P; Williams, James A

    2006-11-01

    Bacterial plasmids are the vectors of choice for DNA vaccines and short-term gene therapeutics. Growing plasmid DNA by microbial (Escherichia coli) fermentation is usually combined with alkaline lysis/chromatography methods of purification. To date, typical plasmid fermentation media and processes result in yields of 100-250 mg of plasmid DNA/l of culture medium, using standard high-copy pUC origin-containing plasmids. In order to address this initial and yield-limiting upstream step, we identified novel fermentation control parameters for fed-batch fermentation. The resulting fermentation strategies significantly increased specific plasmid yield with respect to cell mass while enhancing plasmid integrity and maintaining supercoiled DNA content. Fed-batch fermentation yield exceeding 1000 mg of plasmid DNA/l was obtained after reduction of plasmid-mediated metabolic burden during growth, and yields up to 1500 mg of plasmid DNA/l have been achieved with optimized plasmid backbones. Interestingly, by inducing high plasmid levels after sufficient biomass accumulation at low temperature and restricted growth, cells were able to tolerate significantly higher plasmid quantities than cells grown by conventional processes. This 5-10-fold increase in plasmid yield dramatically decreases plasmid manufacturing costs and improves the effectiveness of downstream purification by reducing the fraction of impurities. PMID:16819941

  6. Ferritinophagy drives uropathogenic Escherichia coli persistence in bladder epithelial cells.

    Bauckman, Kyle A; Mysorekar, Indira U

    2016-05-01

    Autophagy is a cellular recycling pathway, which in many cases, protects host cells from infections by degrading pathogens. However, uropathogenic Escherichia coli (UPEC), the predominant cause of urinary tract infections (UTIs), persist within the urinary tract epithelium (urothelium) by forming reservoirs within autophagosomes. Iron is a critical nutrient for both host and pathogen, and regulation of iron availability is a key host defense against pathogens. Iron homeostasis depends on the shuttling of iron-bound ferritin to the lysosome for recycling, a process termed ferritinophagy (a form of selective autophagy). Here, we demonstrate for the first time that UPEC shuttles with ferritin-bound iron into the autophagosomal and lysosomal compartments within the urothelium. Iron overload in urothelial cells induces ferritinophagy in an NCOA4-dependent manner causing increased iron availability for UPEC, triggering bacterial overproliferation and host cell death. Addition of even moderate levels of iron is sufficient to increase and prolong bacterial burden. Furthermore, we show that lysosomal damage due to iron overload is the specific mechanism causing host cell death. Significantly, we demonstrate that host cell death and bacterial burden can be reversed by inhibition of autophagy or inhibition of iron-regulatory proteins, or chelation of iron. Together, our findings suggest that UPEC persist in host cells by taking advantage of ferritinophagy. Thus, modulation of iron levels in the bladder may provide a therapeutic avenue to controlling UPEC persistence, epithelial cell death, and recurrent UTIs. PMID:27002654

  7. Cadmium biosorption by polyvinyl alcohol immobilized recombinant Escherichia coli

    Recombinant Escherichia coli expressing human metallothionein protein was immobilized with polyvinyl alcohol (PVA) for the removal of cadmium from solution. The adsorption ability was strongly affected by pH with optimal performance at pH 5.0, while it was less sensitive to temperature over the range of 20-42 deg. C. The adsorption kinetics and equilibrium of PVA-immobilized cells was best described by pseudo-second order model and Langmuir isotherm, respectively. Over the Cd concentrations range of 10-150 mg/l, PVA-cells had the highest Cd removal percentage (82.7%) at 10 mg Cd/l and a biomass loading of 15.4 wt.%. Better adsorption ability was obtained when biomass loading was increased, as the highest adsorption capacity of 4.29 mg/g was achieved at 33.0 wt.% of biomass (initial Cd concentration = 100 mg/l). An aqueous solution of 0.01 M Na3NTA displayed the best desorption efficiency (57-89%) for four A/D cycles, while 51-61% of the original adsorption capacity was retained after regeneration.

  8. Recombination Phenotypes of Escherichia coli greA Mutants

    Poteete Anthony R

    2011-03-01

    Full Text Available Abstract Background The elongation factor GreA binds to RNA polymerase and modulates transcriptional pausing. Some recent research suggests that the primary role of GreA may not be to regulate gene expression, but rather, to promote the progression of replication forks which collide with RNA polymerase, and which might otherwise collapse. Replication fork collapse is known to generate dsDNA breaks, which can be recombinogenic. It follows that GreA malfunction could have consequences affecting homologous recombination. Results Escherichia coli mutants bearing substitutions of the active site acidic residues of the transcription elongation factor GreA, D41N and E44K, were isolated as suppressors of growth inhibition by a toxic variant of the bacteriophage lambda Red-beta recombination protein. These mutants, as well as a D41A greA mutant and a greA deletion, were tested for proficiency in recombination events. The mutations were found to increase the efficiency of RecA-RecBCD-mediated and RecA-Red-mediated recombination, which are replication-independent, and to decrease the efficiency of replication-dependent Red-mediated recombination. Conclusion These observations provide new evidence for a role of GreA in resolving conflicts between replication and transcription.

  9. An Integrated System for Precise Genome Modification in Escherichia coli.

    Tas, Huseyin; Nguyen, Cac T; Patel, Ravish; Kim, Neil H; Kuhlman, Thomas E

    2015-01-01

    We describe an optimized system for the easy, effective, and precise modification of the Escherichia coli genome. Genome changes are introduced first through the integration of a 1.3 kbp Landing Pad consisting of a gene conferring resistance to tetracycline (tetA) or the ability to metabolize the sugar galactose (galK). The Landing Pad is then excised as a result of double-strand breaks by the homing endonuclease I-SceI, and replaced with DNA fragments bearing the desired change via λ-Red mediated homologous recombination. Repair of the double strand breaks and counterselection against the Landing Pad (using NiCl2 for tetA or 2-deoxy-galactose for galK) allows the isolation of modified bacteria without the use of additional antibiotic selection. We demonstrate the power of this method to make a variety of genome modifications: the exact integration, without any extraneous sequence, of the lac operon (~6.5 kbp) to any desired location in the genome and without the integration of antibiotic markers; the scarless deletion of ribosomal rrn operons (~6 kbp) through either intrachromosomal or oligonucleotide recombination; and the in situ fusion of native genes to fluorescent reporter genes without additional perturbation. PMID:26332675

  10. An Integrated System for Precise Genome Modification in Escherichia coli.

    Huseyin Tas

    Full Text Available We describe an optimized system for the easy, effective, and precise modification of the Escherichia coli genome. Genome changes are introduced first through the integration of a 1.3 kbp Landing Pad consisting of a gene conferring resistance to tetracycline (tetA or the ability to metabolize the sugar galactose (galK. The Landing Pad is then excised as a result of double-strand breaks by the homing endonuclease I-SceI, and replaced with DNA fragments bearing the desired change via λ-Red mediated homologous recombination. Repair of the double strand breaks and counterselection against the Landing Pad (using NiCl2 for tetA or 2-deoxy-galactose for galK allows the isolation of modified bacteria without the use of additional antibiotic selection. We demonstrate the power of this method to make a variety of genome modifications: the exact integration, without any extraneous sequence, of the lac operon (~6.5 kbp to any desired location in the genome and without the integration of antibiotic markers; the scarless deletion of ribosomal rrn operons (~6 kbp through either intrachromosomal or oligonucleotide recombination; and the in situ fusion of native genes to fluorescent reporter genes without additional perturbation.

  11. Characterization of RNA damage under oxidative stress in Escherichia coli

    Liu, Min; Gong, Xin; Alluri, Ravi Kumar; Wu, Jinhua; Sablo, Tene’; Li, Zhongwei

    2012-01-01

    We have examined the level of 8-hydroxyguanosine (8-oxo-G), an oxidized form of guanosine, in RNA in Escherichia coli under normal and oxidative stress conditions. The level of 8-oxo-G in RNA rises rapidly and remains high for hours in response to hydrogen peroxide (H2O2) challenge in a dose-dependent manner. H2O2 induced elevation of 8-oxo-G content is much higher in RNA than that of 8-hydroxydeoxyguanosine (8-oxo-dG) in DNA. Under normal conditions, the 8-oxo-G level is low in RNA isolated from the ribosome and it is nearly three times higher in non-ribosomal RNAs. In contrast, 8-oxo-G generated by a short exposure to H2O2 is almost equally distributed in various RNA species, suggesting that although ribosomal RNAs are normally less oxidized, they are not protected against exogenous H2O2. Interestingly, highly folded RNA is not protected from oxidation because 8-oxo-G generated by H2O2 treatment in vitro increases to approximately the same levels in tRNA and rRNA in both native and denatured forms. Lastly, increased RNA oxidation is closely associated with cell death by oxidative stress. Our data suggests that RNA is a primary target for reactive oxygen species and RNA oxidation is part of the paradox that cells have to deal with under oxidative stress. PMID:22718628

  12. Polynucleotide Phosphorylase Protects Escherichia coli against Oxidative Stress†

    Wu, Jinhua; Jiang, Zhe; Liu, Min; Gong, Xin; Wu, Shaohui; Burns, Christopher M.; Li, Zhongwei

    2009-01-01

    Escherichia coli polynucleotide phosphorylase (PNPase) primarily functions in RNA degradation. It is an exoribonuclease and integral component of the multienzyme RNA degradosome complex [Carpousis et al. (1994) Cell 76, 889]. PNPase was previously shown to specifically bind a synthetic RNA containing the oxidative lesion 8-hydroxyguanine (8-oxoG) [Hayakawa et al. (2001) Biochemistry 40, 9977], suggesting a possible role in removing oxidatively damaged RNA. Here we show that PNPase binds to RNA molecules of natural sequence that were oxidatively damaged by treatment with hydrogen peroxide (H2O2) postsynthetically. PNPase bound oxidized RNA with higher affinity than untreated RNA of the same sequence, raising the possibility that it may act against a wide variety of lesions. The importance of such a protective role is illustrated by the observation that, under conditions known to cause oxidative damage to cytoplasmic components, PNPase-deficient cells are less viable than wild-type cells. Further, when challenged with H2O2, PNPase-deficient cells accumulate 8-oxoG in cellular RNA to a greater extent than wild-type cells, suggesting that this RNase functions in minimizing oxidized RNA in vivo. Introducing the pnp gene encoding PNPase rescues defects in growth and RNA quality of the pnp mutant cells. Our results also suggest that protection against oxidative stress is an intrinsic function of PNPase because association with the RNA degradosome or with RNA helicase B (RhlB) is not required. PMID:19219992

  13. Penicillin-binding site on the Escherichia coli cell envelope

    The binding of 35S-labeled penicillin to distinct penicillin-binding proteins (PBPs) of the cell envelope obtained from the sonication of Escherichia coli was studied at different pHs ranging from 4 to 11. Experiments distinguishing the effect of pH on penicillin binding by PBP 5/6 from its effect on beta-lactamase activity indicated that although substantial binding occurred at the lowest pH, the amount of binding increased with pH, reaching a maximum at pH 10. Based on earlier studies, it is proposed that the binding at high pH involves the formation of a covalent bond between the C-7 of penicillin and free epsilon amino groups of the PBPs. At pHs ranging from 4 to 8, position 1 of penicillin, occupied by sulfur, is considered to be the site that establishes a covalent bond with the sulfhydryl groups of PBP 5. The use of specific blockers of free epsilon amino groups or sulfhydryl groups indicated that wherever the presence of each had little or no effect on the binding of penicillin by PBP 5, the presence of both completely prevented binding. The specific blocker of the hydroxyl group of serine did not affect the binding of penicillin

  14. Expression of Plasmodium falciparum lactate dehydrogenase in Escherichia coli.

    Bzik, D J; Fox, B A; Gonyer, K

    1993-05-01

    A Plasmodium falciparum gene is described which encodes lactate dehydrogenase activity (P. falciparum LDH). The P. falciparum LDH gene contains no introns and is present in a single copy on chromosome 13. P. falciparum LDH was expressed in all asexual blood stages as a 1.6-kb mRNA. The predicted 316 amino acid protein coding region of P. falciparum LDH was inserted into the prokaryotic expression vector pKK223-3 and a 33-kDa protein having LDH activity was synthesized in Escherichia coli. P. falciparum LDH primary structure displays high amino acid similarity (50-57%) to vertebrate and bacterial LDH, but lacks the amino terminal extension observed in all vertebrate LDH. The majority of amino acid residues implicated in substrate and coenzyme binding and catalysis of other LDH are well conserved in P. falciparum LDH. However, several notable differences in amino acid composition were observed. P. falciparum LDH contained several distinctive single amino acid insertions and deletions compared to other LDH enzymes, and most remarkably, it contained a novel insertion of 5 amino acids within the conserved mobile loop region near arginine residue 109, a residue which is known to make contact with pyruvate in the ternary complex of other LDH. These results suggest that novel features of P. falciparum LDH primary structure may be correlated with previously characterized and distinctive kinetic, biochemical, immunochemical, and electrophoretic properties of P. falciparum LDH. PMID:8515777

  15. Expression of fully functional tetrameric human hemoglobin in Escherichia coli

    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 chain also contains an additional methionine as an extension to the amino terminus. The recombinant hemoglobin has a C4 reversed-phase HPLC profile essentially identical to that of human hemoglobin A0 and comigrates with hemoglobin A0 on SDS/PAGE. The visible spectrum and oxygen affinity are similar to that of native human hemoglobin A0. The authors have also expressed the α- and β-globin genes separately and found that the expression of the α-globin gene alone results in a marked decrease in the accumulation of α-globin in the cell. Separate expression of the β-globin gene results in high levels of insoluble β-globin. These observations suggest that the presence of α- and β-globin in the same cell stabilizes α-globin and aids the correct folding of β-globin. This system provides a simple method for expressing large quantities of recombinant hemoglobin and allows facile manipulation of the genes encoding hemoglobin to produce functionally altered forms of this protein

  16. Escherichia coli modulates its motor speed on sensing an attractant.

    Karmakar, Richa; Naaz, Farha; Tirumkudulu, Mahesh S; Venkatesh, K V

    2016-10-01

    It is well known that Escherichia coli achieves chemotaxis by modulating the bias of the flagellar motor. Recent experiments have shown that the bacteria vary their swimming speeds as well in presence of attractants. However, this increase in the swimming speed in response to the attractants has not been correlated with the increase in the flagellar motor speed. Using flickering dark-field microscopy, we measure the head-rotation speed of a large population of cells to correlate it with the flagellar motor speed. Experiments performed with wild-type and trg-deletion mutant strains suggest that the cells are capable of modulating the flagellar motor speed via mere sensing of a ligand. The motor speed can be further correlated with the swimming speed of the cells and was found to be linear. These results suggest the existence of a hitherto unknown intra-cellular pathway that modulates the flagellar motor speed in response to sensing of chemicals, thereby making chemotaxis more efficient than previously known. PMID:27318664

  17. Mutagenic DNA repair in Escherichia coli: Pt. 18

    UV light was unable to induce rifampicin-resistant mutations at 430C in Escherichia coli ER11 and dnaE486. Although DnaE486 gene product is inactive at 430C, these bacteria contain the pcbA1 mutation which allows DNA replication provided DNA polymerase I is functional. The experiments were carried out under conditions where full expression of rifampicin-resistant mutations could occur so that the lack of induced mutations cannot be ascribed to an effect of incubation at 430C on mutation expression. UV-mutability at 43(0)C was restored by the presence of the dnaE+ allele on a plasmid. It is concluded that functional DnaE protein is essential for UV mutagenesis. The dnaE486 mutation also blocked the induction at 430C of mutations induced by UV plus delayed photoreversal, a procedure that has been postulated to reflect an early misincorporation step in the UV mutagenic process. (Author)

  18. Signal integration in the galactose network of Escherichia coli.

    Semsey, Szabolcs; Krishna, Sandeep; Sneppen, Kim; Adhya, Sankar

    2007-07-01

    The gal regulon of Escherichia coli contains genes involved in galactose transport and metabolism. Transcription of the gal regulon genes is regulated in different ways by two iso-regulatory proteins, Gal repressor (GalR) and Gal isorepressor (GalS), which recognize the same binding sites in the absence of d-galactose. DNA binding by both GalR and GalS is inhibited in the presence of d-galactose. Many of the gal regulon genes are activated in the presence of the adenosine cyclic-3',5'-monophosphate (cAMP)-cAMP receptor protein (CRP) complex. We studied transcriptional regulation of the gal regulon promoters simultaneously in a purified system and attempted to integrate the two small molecule signals, d-galactose and cAMP, that modulate the isoregulators and CRP respectively, at each promoter, using Boolean logic. Results show that similarly organized promoters can have different input functions. We also found that in some cases the activity of the promoter and the cognate gene can be described by different logic gates. We combined the transcriptional network of the galactose regulon, obtained from our experiments, with literature data to construct an integrated map of the galactose network. Structural analysis of the network shows that at the interface of the genetic and metabolic network, feedback loops are by far the most common motif. PMID:17630975

  19. Photoluminescent gold nanoclusters as sensing probes for uropathogenic Escherichia coli.

    Po-Han Chan

    Full Text Available Glycan-bound nanoprobes have been demonstrated as suitable sensing probes for bacteria containing glycan binding sites. In this study, we demonstrated a facile approach for generating glycan-bound gold nanoclusters (AuNCs. The generated AuNCs were used as sensing probes for corresponding target bacteria. Mannose-capped AuNCs (AuNCs@Mann were generated and used as the model sensors for target bacteria. A one-step synthesis approach was employed to generate AuNCs@Mann. In this approach, an aqueous solution of tetrachloroauric acid and mannoside that functionized with a thiol group (Mann-SH was stirred at room temperature for 48 h. The mannoside functions as reducing and capping agent. The size of the generated AuNCs@Mann is 1.95±0.27 nm, whereas the AuNCs with red photoluminescence have a maximum emission wavelength of ~630 nm (λexcitation = 375 nm. The synthesis of the AuNCs@Mann was accelerated by microwave heating, which enabled the synthesis of the AuNCs@Mann to complete within 1 h. The generated AuNCs@Mann are capable of selectively binding to the urinary tract infection isolate Escherichia coli J96 containing the mannose binding protein FimH expressed on the type 1 pili. On the basis of the naked eye observation, the limit of detection of the sensing approach is as low as ~2×10(6 cells/mL.

  20. Chemotactic response and adaptation dynamics in Escherichia coli.

    Diana Clausznitzer

    2010-05-01

    Full Text Available Adaptation of the chemotaxis sensory pathway of the bacterium Escherichia coli is integral for detecting chemicals over a wide range of background concentrations, ultimately allowing cells to swim towards sources of attractant and away from repellents. Its biochemical mechanism based on methylation and demethylation of chemoreceptors has long been known. Despite the importance of adaptation for cell memory and behavior, the dynamics of adaptation are difficult to reconcile with current models of precise adaptation. Here, we follow time courses of signaling in response to concentration step changes of attractant using in vivo fluorescence resonance energy transfer measurements. Specifically, we use a condensed representation of adaptation time courses for efficient evaluation of different adaptation models. To quantitatively explain the data, we finally develop a dynamic model for signaling and adaptation based on the attractant flow in the experiment, signaling by cooperative receptor complexes, and multiple layers of feedback regulation for adaptation. We experimentally confirm the predicted effects of changing the enzyme-expression level and bypassing the negative feedback for demethylation. Our data analysis suggests significant imprecision in adaptation for large additions. Furthermore, our model predicts highly regulated, ultrafast adaptation in response to removal of attractant, which may be useful for fast reorientation of the cell and noise reduction in adaptation.

  1. Non-genetic individuality in Escherichia coli motor switching

    By analyzing 30 min, high-resolution recordings of single Escherichia coli flagellar motors in the physiological regime, we show that two main properties of motor switching—the mean clockwise and mean counter-clockwise interval durations—vary significantly. When we represent these quantities on a two-dimensional plot for several cells, the data do not fall on a one-dimensional curve, as expected with a single control parameter, but instead spread in two dimensions, pointing to motor individuality. The largest variations are in the mean counter-clockwise interval, and are attributable to variations in the concentration of the internal signaling molecule CheY-P. In contrast, variations in the mean clockwise interval are interpreted in terms of motor individuality. We argue that the sensitivity of the mean counter-clockwise interval to fluctuations in CheY-P is consistent with an optimal strategy of run and tumble. The concomittent variability in mean run length may allow populations of cells to better survive in rapidly changing environments by 'hedging their bets'. (communication)

  2. Oxidative Stress in Shiga Toxin Production by Enterohemorrhagic Escherichia coli

    Katarzyna Licznerska

    2016-01-01

    Full Text Available Virulence of enterohemorrhagic Escherichia coli (EHEC strains depends on production of Shiga toxins. These toxins are encoded in genomes of lambdoid bacteriophages (Shiga toxin-converting phages, present in EHEC cells as prophages. The genes coding for Shiga toxins are silent in lysogenic bacteria, and prophage induction is necessary for their efficient expression and toxin production. Under laboratory conditions, treatment with UV light or antibiotics interfering with DNA replication are commonly used to induce lambdoid prophages. Since such conditions are unlikely to occur in human intestine, various research groups searched for other factors or agents that might induce Shiga toxin-converting prophages. Among other conditions, it was reported that treatment with H2O2 caused induction of these prophages, though with efficiency significantly lower relative to UV-irradiation or mitomycin C treatment. A molecular mechanism of this phenomenon has been proposed. It appears that the oxidative stress represents natural conditions provoking induction of Shiga toxin-converting prophages as a consequence of H2O2 excretion by either neutrophils in infected humans or protist predators outside human body. Finally, the recently proposed biological role of Shiga toxin production is described in this paper, and the “bacterial altruism” and “Trojan Horse” hypotheses, which are connected to the oxidative stress, are discussed.

  3. Oxidative Stress in Shiga Toxin Production by Enterohemorrhagic Escherichia coli.

    Licznerska, Katarzyna; Nejman-Faleńczyk, Bożena; Bloch, Sylwia; Dydecka, Aleksandra; Topka, Gracja; Gąsior, Tomasz; Węgrzyn, Alicja; Węgrzyn, Grzegorz

    2016-01-01

    Virulence of enterohemorrhagic Escherichia coli (EHEC) strains depends on production of Shiga toxins. These toxins are encoded in genomes of lambdoid bacteriophages (Shiga toxin-converting phages), present in EHEC cells as prophages. The genes coding for Shiga toxins are silent in lysogenic bacteria, and prophage induction is necessary for their efficient expression and toxin production. Under laboratory conditions, treatment with UV light or antibiotics interfering with DNA replication are commonly used to induce lambdoid prophages. Since such conditions are unlikely to occur in human intestine, various research groups searched for other factors or agents that might induce Shiga toxin-converting prophages. Among other conditions, it was reported that treatment with H2O2 caused induction of these prophages, though with efficiency significantly lower relative to UV-irradiation or mitomycin C treatment. A molecular mechanism of this phenomenon has been proposed. It appears that the oxidative stress represents natural conditions provoking induction of Shiga toxin-converting prophages as a consequence of H2O2 excretion by either neutrophils in infected humans or protist predators outside human body. Finally, the recently proposed biological role of Shiga toxin production is described in this paper, and the "bacterial altruism" and "Trojan Horse" hypotheses, which are connected to the oxidative stress, are discussed. PMID:26798420

  4. Stochastic switching induced adaptation in a starved Escherichia coli population.

    Shimizu, Yoshihiro; Tsuru, Saburo; Ito, Yoichiro; Ying, Bei-Wen; Yomo, Tetsuya

    2011-01-01

    Population adaptation can be determined by stochastic switching in living cells. To examine how stochastic switching contributes to the fate decision for a population under severe stress, we constructed an Escherichia coli strain crucially dependent on the expression of a rewired gene. The gene essential for tryptophan biosynthesis, trpC, was removed from the native regulatory unit, the Trp operon, and placed under the extraneous control of the lactose utilisation network. Bistability of the network provided the cells two discrete phenotypes: the induced and suppressed level of trpC. The two phenotypes permitted the cells to grow or not, respectively, under conditions of tryptophan depletion. We found that stochastic switching between the two states allowed the initially suppressed cells to form a new population with induced trpC in response to tryptophan starvation. However, the frequency of the transition from suppressed to induced state dropped off dramatically in the starved population, in comparison to that in the nourished population. This reduced switching rate was compensated by increasing the initial population size, which probably provided the cell population more chances to wait for the rarely appearing fit cells from the unfit cells. Taken together, adaptation of a starved bacterial population because of stochasticity in the gene rewired from the ancient regulon was experimentally confirmed, and the nutritional status and the population size played a great role in stochastic adaptation. PMID:21931628

  5. Stochastic switching induced adaptation in a starved Escherichia coli population.

    Yoshihiro Shimizu

    Full Text Available Population adaptation can be determined by stochastic switching in living cells. To examine how stochastic switching contributes to the fate decision for a population under severe stress, we constructed an Escherichia coli strain crucially dependent on the expression of a rewired gene. The gene essential for tryptophan biosynthesis, trpC, was removed from the native regulatory unit, the Trp operon, and placed under the extraneous control of the lactose utilisation network. Bistability of the network provided the cells two discrete phenotypes: the induced and suppressed level of trpC. The two phenotypes permitted the cells to grow or not, respectively, under conditions of tryptophan depletion. We found that stochastic switching between the two states allowed the initially suppressed cells to form a new population with induced trpC in response to tryptophan starvation. However, the frequency of the transition from suppressed to induced state dropped off dramatically in the starved population, in comparison to that in the nourished population. This reduced switching rate was compensated by increasing the initial population size, which probably provided the cell population more chances to wait for the rarely appearing fit cells from the unfit cells. Taken together, adaptation of a starved bacterial population because of stochasticity in the gene rewired from the ancient regulon was experimentally confirmed, and the nutritional status and the population size played a great role in stochastic adaptation.

  6. Expanded flux variability analysis on metabolic network of Escherichia coli

    CHEN Tong; XIE ZhengWei; OUYANG Qi

    2009-01-01

    Flux balance analysis,based on the mass conservation law in a cellular organism,has been extensively employed to study the interplay between structures and functions of cellular metabolic networks.Consequently,the phenotypes of the metabolism can be well elucidated.In this paper,we introduce the Expanded Flux Variability Analysis (EFVA) to characterize the intrinsic nature of metabolic reactions,such as flexibility,modularity and essentiality,by exploring the trend of the range,the maximum and the minimum flux of reactions.We took the metabolic network of Escherichia coli as an example and analyzed the variability of reaction fluxes under different growth rate constraints.The average variability of all reactions decreases dramatically when the growth rate increases.Consider the noise effect on the metabolic system,we thus argue that the microorganism may practically grow under a suboptimal state.Besides,under the EFVA framework,the reactions are easily to be grouped into catabolic and anabolic groups.And the anabolic groups can be further assigned to specific biomass constitute.We also discovered the growth rate dependent essentiality of reactions.

  7. Expression of fully functional tetrameric human hemoglobin in Escherichia coli

    Hoffman, S.J.; Looker, D.L.; Roehrich, J.M.; Cozart, P.E.; Durfee, S.L.; Tedesco, J.L.; Stetler, G.L. (Somatogen, Inc., Broomfield, CO (United States))

    1990-11-01

    Synthesis 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 chain also contains an additional methionine as an extension to the amino terminus. The recombinant hemoglobin has a C{sub 4} reversed-phase HPLC profile essentially identical to that of human hemoglobin A{sub 0} and comigrates with hemoglobin A{sub 0} on SDS/PAGE. The visible spectrum and oxygen affinity are similar to that of native human hemoglobin A{sub 0}. The authors have also expressed the {alpha}- and {beta}-globin genes separately and found that the expression of the {alpha}-globin gene alone results in a marked decrease in the accumulation of {alpha}-globin in the cell. Separate expression of the {beta}-globin gene results in high levels of insoluble {beta}-globin. These observations suggest that the presence of {alpha}- and {beta}-globin in the same cell stabilizes {alpha}-globin and aids the correct folding of {beta}-globin. This system provides a simple method for expressing large quantities of recombinant hemoglobin and allows facile manipulation of the genes encoding hemoglobin to produce functionally altered forms of this protein.

  8. Resolving Holliday junctions with Escherichia coli UvrD helicase.

    Carter, Annamarie S; Tahmaseb, Kambiz; Compton, Sarah A; Matson, Steven W

    2012-03-01

    The Escherichia coli UvrD helicase is known to function in the mismatch repair and nucleotide excision repair pathways and has also been suggested to have roles in recombination and replication restart. The primary intermediate DNA structure in these two processes is the Holliday junction. UvrD has been shown to unwind a variety of substrates including partial duplex DNA, nicked DNA, forked DNA structures, blunt duplex DNA and RNA-DNA hybrids. Here, we demonstrate that UvrD also catalyzes the robust unwinding of Holliday junction substrates. To characterize this unwinding reaction we have employed steady-state helicase assays, pre-steady-state rapid quench helicase assays, DNaseI footprinting, and electron microscopy. We conclude that UvrD binds initially to the junction compared with binding one of the blunt ends of the four-way junction to initiate unwinding and resolves the synthetic substrate into two double-stranded fork structures. We suggest that UvrD, along with its mismatch repair partners, MutS and MutL, may utilize its ability to unwind Holliday junctions directly in the prevention of homeologous recombination. UvrD may also be involved in the resolution of stalled replication forks by unwinding the Holliday junction intermediate to allow bypass of the blockage. PMID:22267744

  9. Fast, multiphase volume adaptation to hyperosmotic shock by Escherichia coli.

    Teuta Pilizota

    Full Text Available All living cells employ an array of different mechanisms to help them survive changes in extra cellular osmotic pressure. The difference in the concentration of chemicals in a bacterium's cytoplasm and the external environment generates an osmotic pressure that inflates the cell. It is thought that the bacterium Escherichia coli use a number of interconnected systems to adapt to changes in external pressure, allowing them to maintain turgor and live in surroundings that range more than two-hundred-fold in external osmolality. Here, we use fluorescence imaging to make the first measurements of cell volume changes over time during hyperosmotic shock and subsequent adaptation on a single cell level in vivo with a time resolution on the order of seconds. We directly observe two previously unseen phases of the cytoplasmic water efflux upon hyperosmotic shock. Furthermore, we monitor cell volume changes during the post-shock recovery and observe a two-phase response that depends on the shock magnitude. The initial phase of recovery is fast, on the order of 15-20 min and shows little cell-to-cell variation. For large sucrose shocks, a secondary phase that lasts several hours adds to the recovery. We find that cells are able to recover fully from shocks as high as 1 Osmol/kg using existing systems, but that for larger shocks, protein synthesis is required for full recovery.

  10. Mutators and hypermutability in bacteria: the Escherichia coli paradigm

    R. Jayaraman

    2009-12-01

    Mutators (also called hypermutators) are mutants which show higher than normal spontaneous mutation frequencies, ranging from 10–20 fold to 100–1000 fold higher, or sometimes even more, than wild-type cells. Being a mutator is advantageous to the organism when adapting to environmental changes or stressful situations, such as moving from one habitat to another, one host to another, exposure to antibiotics etc. However, this advantage is only a short-term benefit. In the long run, hypermutability leads to a fitness disadvantage due to accumulation of deleterious mutations or antagonistic pleiotropy or both. Contrary to intuitive expectations, hypermutability is commonly encountered in natural bacterial populations, especially among clinical isolates. It is believed to be involved in the emergence of antibiotic resistance and a hindrance to the treatment of infectious diseases. Here, I review the state of knowledge on the common mechanisms of hypermutability such as errors/defects in DNA replication, proof reading, mismatch repair, oxidative DNA damage, mistranslation etc., as well as phenomena associated with these processes, using Escherichia coli as a paradigmatic organism.

  11. Molecular detection and identification of intimin alleles in pathogenic Escherichia coli by multiplex PCR.

    Reid, S D; Betting, D J; Whittam, T S

    1999-08-01

    A multiplex PCR was designed to detect the eae gene and simultaneously identify specific alleles in pathogenic Escherichia coli. The method was tested on 87 strains representing the diarrheagenic E. coli clones. The results show that the PCR assay accurately detects eae and resolves alleles encoding the alpha, beta, and gamma intimin variants. PMID:10405431

  12. Vicinal Dithiol-Disulfide Distribution in the Escherichia coli Mannitol Specific Carrier Enzyme IImtl

    Roossien, F.F.; Robillard, G.T.

    1984-01-01

    Escherichia coli mannitol specific EII in membrane vesicles can be inhibited by the action of the oxidizable substrate-reduced phenazine methosulfate (PMS) in a manner similar to E. coli enzyme IIGlc. The fact that reduced PMS and various oxidizing agents protect the enzyme from inactivation by the

  13. Phosphoribosylpyrophosphate (PRPP)-less mutants of Escherichia coli

    Hove-Jensen, Bjarne

    1989-01-01

    A DNA fragment encoding kanamycin resistance was inserted in vitro into a plasmid-borne prs gene encoding phosphoribosylpyrophosphate synthetase of Escherichia coli. The resulting plasmids were subsequently transferred to the chromosome by homologous recombination and the haploid strains prs-3::Kan...... phosphoribosylpyrophosphate synthetase is dispensable for E. coli....

  14. DNA probes for K-antigen (capsule) typing of Escherichia coli.

    Roberts, M.; Roberts, I.; Korhonen, T K; Jann, K; Bitter-Suermann, D; Boulnois, G J; Williams, P H

    1988-01-01

    DNA restriction fragments derived from the polysaccharide biosynthesis regions of cloned Escherichia coli K1, K5, and K12 capsular antigen genes hybridized only with DNA of strains determined by conventional methods to be of the same K serotype. A probe derived from the common transport region hybridized to all encapsulated E. coli strains.

  15. Establishing Streptomycin Epidemiological Cut-Off Values for Salmonella and Escherichia coli

    Migura, Lourdes Garcia; Sunde, Marianne; Karlsmose, Susanne;

    2011-01-01

    This study was conducted to elucidate the accuracy of the current streptomycin epidemiological cut-off value (ECOFF) for Escherichia coli and Salmonella spp. A total of 236 Salmonella enterica and 208 E. coli isolates exhibiting MICs between 4 and 32 mg/L were selected from 12 countries. Isolates...

  16. Rapid Extraction of DNA From Escherichia coli and Cryptosporidium parvum for Use in PCR

    Higgins, James A.; Jenkins, Mark C.; Shelton, Daniel R.; Fayer, Ron; Karns, Jeffrey S.

    2001-01-01

    The Xtra Amp tube, Isocode paper, Instagene matrix, and PrepMan matrix methods were evaluated for their ability to rapidly extract PCR-quality DNAs from Escherichia coli O157:H7 and Cryptosporidium parvum. All methods provided satisfactory DNA from E. coli, and the Xtra Amp and Instagene reagents provided satisfactory DNA from C. parvum.

  17. Mechanisms of Reduced Susceptibility to Ciprofloxacin in Escherichia coli Isolates from Canadian Hospitals

    Patricia J Baudry-Simner

    2012-01-01

    Full Text Available OBJECTIVE: To determine whether plasmid-mediated quinolone resistance (PMQR determinants play a role in the increasing resistance to fluoroquinolones among Escherichia coli isolates in Canadian hospitals, and to determine the mechanisms of reduced susceptibility to ciprofloxacin in a recent collection of 190 clinical E coli isolates.

  18. Complete genome sequence and comparison of two Shiga toxin-producing Escherichia coli O104 isolates

    Shiga toxin-producing Escherichia coli (STEC) O104 strains have been associated with sporadic cases of illness and have caused outbreaks associated with milk and sprouts. E. coli O104:H21 caused an outbreak associated with milk in the U.S. in 1994. In this study, next generation sequencing techno...

  19. Efficacy of supercritical carbon dioxide for nonthermal inactivation of Escherichia coli K12 in apple cider

    This study evaluated the efficacy of a supercritical carbon dioxide (SCCO2) system with a gas-liquid porous metal contactor for eliminating Escherichia coli K12 in apple cider. Pasteurized, preservative-free apple cider was inoculated with E. coli K12 and processed using the SCCO2 system at CO2 conc...

  20. Crude extract of maggots: Antibacterial effects against Escherichia coli, underlying mechanisms, separation and purification

    Ge, Quan-Sheng; Zhang, Hui-Min; Liu, Xia; Wang, Shou-Yu; Lv, De-Cheng; LI, Xu-dong

    2015-01-01

    AIM: To investigate the antibacterial effects of a crude extract of maggots against Escherichia coli (E. coli) and the underlying mechanisms, and to separate and purify the crude extract of maggots to assess the antibacterial effects of the active ingredients in the crude extract.

  1. Proliferation of Escherichia coli O157:H7 in soil and hydroponic microgreen production systems

    Radish (Raphanus sativus var. longipinnatus) microgreens were produced from seeds inoculated with Escherichia coli O157: H7 using soil substitute and hydroponic production systems. E. coli populations on the edible and inedible parts of harvested microgreen plants and in growth medium were examined....

  2. Identification of Escherichia coli O157 by Using a Novel Colorimetric Detection Method with DNA Microarrays

    Shiga toxin-producing Escherichia coli O157:H7 is a leading cause of foodborne illness worldwide. To evaluate better methods to rapidly detect and genotype E. coli O157 strains, the present study evaluated the use of ampliPHOX, a novel colorimetric detection method based on photopolymerization, for...

  3. Effects of media on recovery of Escherichia coli 0157:H7 and Pseudomonas fluorescens from spinach

    Control the post-harvest contamination of leafy greens by Escherichia coli O157:H7 is important for food safety. Efficient recovery and enumeration of E. coli O157:H7 and the biocontrol microbe Pseudomonas fluorescens from produce is crucial for assessment of biocontrol efficacy. Sensitive and effec...

  4. Recovery of Escherichia coli from Soil after Addition of Sterile Organic Wastes

    Unc, Adrian; Gardner, Julie; Springthorpe, Susan

    2006-01-01

    Laboratory batch tests indicate that addition of sterile municipal sewage biosolids to clay soil from four depths increases the numbers of Escherichia coli isolates recoverable in EC-MUG broth (EC broth with 4-methylumbelliferyl-β-glucuronide). This effect was most marked for the deeper soil layers, with increases of about 2.6 orders of magnitude in E. coli most probable number.

  5. Haemolytic Escherichia coli isolated from dogs with diarrhea have characteristics of both uropathogenic and necrotoxigenic strains

    Starxix, M.; Johnson, J.R.; Stell, A.L.; Goot, van der J.A.; Hendriks, H.G.; Vorstenbosch, van C.; Dijk, van L.; Gaastra, W.

    2002-01-01

    Twenty-four haemolytic Escherichia coli strains were isolated from dogs with diarrhea. The strains were serotyped and analysed by polymerase chain reaction (PCR) for genes encoding virulence factors associated with E. coli that cause diarrhea in animals. Adhesion antigen production was deduced from

  6. Molecular cloning of the Salmonella typhimurium lep gene in Escherichia coli

    van Dijl, J M; van den Bergh, R; Reversma, T; Smith, H; Bron, S; Venema, G

    1990-01-01

    A system is described which enabled the selection of a heterologous lep gene, encoding signal peptidase I, in Escherichia coli. It is based on complementation of an E. coli mutant, in which the synthesis of signal peptidase I can be regulated. With this system the lep gene of Salmonella typhimurium

  7. Non-functional expression of Escherichia coli signal peptidase I in Bacillus subtilis

    van Dijl, J M; de Jong, A; Smith, H; Bron, S; Venema, G

    1991-01-01

    The Escherichia coli lep gene, encoding signal peptidase I (SPase I) was provided with Bacillus subtilis transcription/translation signals and expressed in this organism. When present on a low-copy-number plasmid, the amount of E. coli SPase I produced (per mg cell protein) in B. subtilis was half t

  8. Serogroups and antimicrobial susceptibility among Escherichia coli isolated from farmed mink (Mustela vison Schreiber) in Denmark

    Vulfson, L.; Pedersen, Karl; Chriel, M.; Frydendahl, K.; Andersen, T.H.; Madsen, Mogens; Dietz, H.H.

    2001-01-01

    Escherichia coli is commonly found in outbreaks of diarrhoea in mink during the production season although its role as a primary causal organism remains unclear. The present study was undertaken to determine the serogroups and antimicrobial susceptibility of E. coli isolates from healthy and diar...

  9. Impact of Diversity of Colonizing Strains on Strategies for Sampling Escherichia coli from Fecal Specimens ▿

    Lautenbach, Ebbing; Bilker, Warren B.; Tolomeo, Pam; Maslow, Joel N.

    2008-01-01

    Of 49 subjects, 21 were colonized with more than one strain of Escherichia coli and 12 subjects had at least one strain present in fewer than 20% of colonies. The ability to accurately characterize E. coli strain diversity is directly related to the number of colonies sampled and the underlying prevalence of the strain.

  10. Impact of Diversity of Colonizing Strains on Strategies for Sampling Escherichia coli from Fecal Specimens ▿

    Lautenbach, Ebbing; Bilker, Warren B.; Tolomeo, Pam; Maslow, Joel N.

    2008-01-01

    Of 49 subjects, 21 were colonized with more than one strain of Escherichia coli and 12 subjects had at least one strain present in fewer than 20% of colonies. The ability to accurately characterize E. coli strain diversity is directly related to the number of colonies sampled and the underlying prevalence of the strain. PMID:18650357

  11. Quantification of survival of Escherichia coli 0157:H7 on Plants affected by Contaminated Irrigation Water

    Enterohemorrhagic E. coli O157: H7 (EHEC) is a major foodborne pathogen capable of causing diarrhea and vomiting, with further complications such as hemolytic-uremic syndrome (HUS). The aim of this study was to use real-time PCR method to quantify the survival of Escherichia coli O157:H7/pGFP in phy...

  12. Antibiotic Resistance in Diarrheagenic Escherichia coli and Shigella Strains Isolated from Children in Hanoi, Vietnam

    Nguyen, Trung Vu; Le Van, Phung; Le, Chinh Huy; Weintraub, Andrej

    2005-01-01

    The MICs for 162 diarrheagenic Escherichia coli strains and 28 Shigella strains were determined on the basis of NCCLS guidelines. More than 75% of the strains were resistant to ampicillin, chloramphenicol (53.6% of Shigella strains), and trimethoprim-sulfamethoxazole. Multiresistance was detected in 89.5% of E. coli strains and 78.6% of Shigella strains.

  13. Heterologous Carotenoid-Biosynthetic Enzymes: Functional Complementation and Effects on Carotenoid Profiles in Escherichia coli

    Song, Gyu Hyeon; Kim, Se Hyeuk; Choi, Bo Hyun; Han, Se Jong; Lee, Pyung Cheon

    2013-01-01

    A limited number of carotenoid pathway genes from microbial sources have been studied for analyzing the pathway complementation in the heterologous host Escherichia coli. In order to systematically investigate the functionality of carotenoid pathway enzymes in E. coli, the pathway genes of carotenogenic microorganisms (Brevibacterium linens, Corynebacterium glutamicum, Rhodobacter sphaeroides, Rhodobacter capsulatus, Rhodopirellula baltica, and Pantoea ananatis) were modified to form syntheti...

  14. Proteomic analysis reveals protein expression differences in Escherichia coli strains associated with persistent versus transient mastitis

    Escherichia coli is a leading cause of bacterial mastitis in dairy cattle. Typically this infection is transient in nature, causing an infection that lasts 2-3 days. However, in a minority of cases, E. coli has been shown to cause a persistent intramammary infection. The mechanisms that allow for...

  15. beta-Chloro-L-alanine inhibition of the Escherichia coli alanine-valine transaminase.

    Whalen, W A; Wang, M D; Berg, C M

    1985-01-01

    beta-Chloro-L-alanine, an amino acid analog which inhibits a number of enzymes, reversibly inhibited the Escherichia coli K-12 alanine-valine transaminase, transaminase C. This inhibition, along with the inhibition of transaminase B, accounted for the isoleucine-plus-valine requirement of E. coli in the presence of beta-chloro-L-alanine.

  16. Dissociation of outer membrane for Escherichia coli cell caused by cerium nitrate

    陈爱美; 施庆珊; 冯劲; 欧阳友生; 陈仪本; 谭绍早

    2010-01-01

    The biological effect of cerium nitrate on the outer membrane(OM) of Escherichia coli(E.coli) cell was studied,and the antim-icrobial mechanism of rare earth elements was explored.The antimicrobial effect of cerium nitrate on E.coli cell was valued by plate count method,and the morphology change of E.coli cell was observed with scanning electron microscopy(SEM) and transmission electron microscopy(TEM).The results showed that the E.coli cell suspension was flocculated when the concentration of Ce(NO3)3?6H2O...

  17. Transduction of Enteric Escherichia coli Isolates with a Derivative of Shiga Toxin 2-Encoding Bacteriophage φ3538 Isolated from Escherichia coli O157:H7

    Schmidt, Herbert; Bielaszewska, Martina; Karch, Helge

    1999-01-01

    We investigated the ability of a detoxified derivative of a Shiga toxin 2 (Stx2)-encoding bacteriophage to infect and lysogenize enteric Escherichia coli strains and to develop infectious progeny from such lysogenized strains. The stx2 gene of the patient E. coli O157:H7 isolate 3538/95 was replaced by the chloramphenicol acetyltransferase (cat) gene from plasmid pACYC184. Phage φ3538(Δstx2::cat) was isolated after induction of E. coli O157:H7 strain 3538/95 with mitomycin. A variety of strai...

  18. Nonpathogenic Escherichia coli Strain Nissle 1917 Inhibits Signal Transduction in Intestinal Epithelial Cells▿

    Kamada, Nobuhiko; Maeda, Kenichi; Inoue, Nagamu; Hisamatsu, Tadakazu; Okamoto, Susumu; Hong, Kyong Su; Yamada, Takaya; Watanabe, Noriaki; Tsuchimoto, Kanji; Ogata, Haruhiko; Hibi, Toshifumi

    2007-01-01

    Although the probiotic Escherichia coli strain Nissle 1917 has been used for the treatment of inflammatory bowel diseases, the precise mechanisms of action of this strain remain unclear. In the present study, we estimated the anti-inflammatory effect of E. coli Nissle 1917 on inflammatory responses in vitro to determine the suppressive mechanism of Nissle 1917 on the inflammatory process. To determine the effect of E. coli Nissle 1917, the human colonic epithelial cell line HCT15 was incubate...

  19. Tissue distribution of a coliphage and Escherichia coli in mussels after contamination and depuration.

    Power, U.F.; Collins, J K

    1990-01-01

    Experiments were undertaken to determine the tissue distribution of Escherichia coli and a coliphage after contamination of the common mussel (Mytilus edulis). Mussels were contaminated with high levels of feces-associated E. coli and a 22-nm icosahedral coliphage over a 2-day period in a flowing-seawater facility. After contamination, individual tissues were carefully dissected and assayed for E. coli and the coliphage. Contaminated mussels were also analyzed to determine the tissue distribu...

  20. Virulence factors and drug resistance in Escherichia coli isolated from extraintestinal infections

    Sharma S; Bhat G; Shenoy S

    2007-01-01

    Purpose: To determine the virulence factors produced by Escherichia coli isolated from extraintestinal infections, to study the drug resistance pattern in E. coli with special reference to extended spectrum β -lactamase (ESBL) and to evaluate screening methods for ESBL. Methods: A total of 152 isolates of E. coli from various extraintestinal infections were screened for virulence factors such as haemolysin, surface hydrophobicity, serum resistance and protease. All the isolates ...

  1. Escherichia coli as an indicator of bacteriological quality of water: an overview

    Stephen T. Odonkor; Joseph K. Ampofo

    2013-01-01

    Monitoring the microbiological quality of drinking water relies largely on examination of indicator bacteria such as coliforms, Escherichia coli, and Pseudomonas aeruginosa. E. coli is a member of the faecal coliform group and is a more specific indicator of faecal pollution than other faecal coliforms. Two key factors have led to the trend toward the use of E. coli as the preferred indicator for the detection of faecal contamination, not only in drinking water, but also in other matrices as ...

  2. Cloning and surface expression of Pseudomonas aeruginosa O antigen in Escherichia coli.

    Goldberg, J B; Hatano, K; Meluleni, G S; Pier, G B

    1992-01-01

    As a step toward developing recombinant oral vaccines, we have explored the feasibility of expression of O polysaccharide antigens from Pseudomonas aeruginosa by Escherichia coli. We cloned in E. coli HB101 a 26.2-kilobase DNA fragment from P. aeruginosa strain PA103 that specifies the production of the O polysaccharide of Fisher immunotype 2 (IT-2) strains. The recombinant organism incorporated the P. aeruginosa IT-2 O polysaccharide onto the core of the E. coli lipopolysaccharide (LPS). Tra...

  3. Prevalence of Shiga toxin genes and intimin genes in uropathogenic Escherichia coli

    Kobra Abbasi; Elahe Tajbakhsh

    2015-01-01

    Objective: To identify stx1, stx2 and eaeA genes in Escherichia coli (E. coli) strains isolated from urine samples in Shahrekord, Iran. Methods: In this cross study a total of 147 middle urine samples from patients with symptoms of urinary tract infection (UTI), referred to clinical laboratories of Shahrekord were studied. Taken samples were cultured to detect Shigatoxin-producing strains and finally 76 E. coli isolates were identified using the standard biochemical tests as we...

  4. Engineering Escherichia Coli Fatty Acid Metabolism for the Production of Biofuel Precursors

    Ford, Tyler John

    2015-01-01

    Medium chain fatty acids (MCFAs, 6-12 carbons) are potential precursors to biofuels with properties similar to gasoline and diesel fuel but are not native products of Escherichia coli fatty acid synthesis. Herein we engineer E. coli to produce, metabolize, and activate MCFAs for their future reduction into alcohols and alkanes (potential biofuels). We develop an E. coli strain with an octanoate (8-carbon MCFA) producing enzyme (a thioesterase), metabolic knockouts, and the capa...

  5. Exposure to the Proton Scavenger Glycine under Alkaline Conditions Induces Escherichia coli Viability Loss

    Donna Vanhauteghem; Geert Paul Jules Janssens; Angelo Lauwaerts; Stanislas Sys; Filip Boyen; Eric Cox; Evelyne Meyer

    2013-01-01

    Our previous work described a clear loss of Escherichia coli (E. coli) membrane integrity after incubation with glycine or its N-methylated derivatives N-methylglycine (sarcosine) and N,N-dimethylglycine (DMG), but not N,N,N-trimethylglycine (betaine), under alkaline stress conditions. The current study offers a thorough viability analysis, based on a combination of real-time physiological techniques, of E. coli exposed to glycine and its N-methylated derivatives at alkaline pH. Flow cytometr...

  6. Antibiotic Resistance Patterns in Enteric and Uropathogenic Strains of Escherichia Coli in Children

    This paper should be cited as: Sedighi I, Alikhani MY, Nakhaee S, Karami P . [ Antibiotic Resistance Patterns in Enteric and Uropathogenic Strains of Escherichia Coli in Children ]. mlj goums . 201 4 ; 8 ( Suppl 4 ): 42 - 48 [Article in Per sian] Sedi ghi, I. (MD); Alikhani, MY. (PhD); Nakhaee, S. (MD); Karami, P. (MSc

    2014-01-01

    Background and Objective: Escherichia coli is the most common cause of urinary tract infections in children and the leading cause of intra-abdominal infections (peritonitis and abscess) followed intestinal injuries. Urinary tract infection, including cystitis and pyelonephritis, is a common childhood infection. E. coli causes more than 90 percent of the community acquired and 50% of hospital acquired urinary tract infections; therefore, the determination of E. coli antibiotic susceptibility i...

  7. Characterization of Unexpected Growth of Escherichia coli O157:H7 by Modeling

    Cornu, Marie; Delignette-Muller, Marie Laure; Flandrois, Jean-Pierre

    1999-01-01

    Modeling of batch kinetics in minimal synthetic medium was used to characterize Escherichia coli O157:H7 growth, which appeared to be different from the exponential growth expected in minimal synthetic medium and observed for E. coli K-12. The turbidimetric kinetics of 14 of the 15 O157:H7 strains tested (93%) were nonexponential, whereas 25 of the 36 other E. coli strains tested (70%) exhibited exponential kinetics. Moreover, the anomaly was almost corrected when the minimal medium was suppl...

  8. Colonization with Extraintestinal Pathogenic Escherichia coli among Nursing Home Residents and Its Relationship to Fluoroquinolone Resistance

    Maslow, Joel N.; Lautenbach, Ebbing; Glaze, Thomas; Bilker, Warren; Johnson, James R.

    2004-01-01

    In a cross-sectional fecal prevalence survey involving 49 residents of a Veterans Affairs nursing home, 59% of subjects were colonized with extraintestinal pathogenic Escherichia coli (ExPEC), 22% were colonized with adhesin-positive E. coli, and 51% were colonized with fluoroquinolone-resistant E. coli. Among 80 unique isolates, adhesins correlated negatively and aerobactin correlated positively with fluoroquinolone resistance. PMID:15328142

  9. Solar and Temporal Effects on Escherichia coli Concentration at a Lake Michigan Swimming Beach†

    Whitman, Richard L.; Nevers, Meredith B.; Korinek, Ginger C.; Byappanahalli, Muruleedhara N.

    2004-01-01

    Studies on solar inactivation of Escherichia coli in freshwater and in situ have been limited. At 63rd St. Beach, Chicago, Ill., factors influencing the daily periodicity of culturable E. coli, particularly insolation, were examined. Water samples for E. coli analysis were collected twice daily between April and September 2000 three times a week along five transects in two depths of water. Hydrometeorological conditions were continuously logged: UV radiation, total insolation, wind speed and ...

  10. Development of a Procedure for Discriminating among Escherichia coli Isolates from Animal and Human Sources

    Guan, Shukui; Xu, Renlin; Chen, Shu; Odumeru, Joseph; Gyles, Carlton

    2002-01-01

    Counts of Escherichia coli cells in water indicate the potential presence of pathogenic microbes of intestinal origin but give no indication of the sources of the microbial pollution. The objective of this research was to evaluate methods for differentiating E. coli isolates of livestock, wildlife, or human origin that might be used to predict the sources of fecal pollution of water. A collection of 319 E. coli isolates from the feces of cattle, poultry, swine, deer, goose, and moose, as well...

  11. DNA Hybridization of Escherichia coli Strains Isolated from Uteri and Fecal Samples of Bitches with Pyometra

    SANCAK, Aziz Arda

    2004-01-01

    Escherichia coli is the most common bacterium that has been isolated from the bacterial culture of uterine and fecal samples of dogs with pyometra. The aim of the present study was to determine whether this organism could be relevant to the pathogenesis of pyometra in dogs. Fecal and uterine samples were collected from 17 bitches with pyometra. E. coli strains were isolated in all samples. Representative colonies of E. coli from each sample were analyzed for pathogenicity determinants by h...

  12. Enterohaemorrhagic Escherichia coli O157: a survey of dairy cattle in Tripoli, Libya

    Ahmed, Mohamed O; Abouzeed, Yousef M

    2014-01-01

    Zoonotic Escherichia coli O157 pathogen represents a serious threat to human health. To investigate the occurrence and prevalence of E. coli O157 among the dairy cattle of Tripoli, Libya, fecal samples were collected intrarectally from 97 outwardly healthy animals and tested by selective plating (Sorbitol-MacConkey agar), biochemical testing (API20E bacterial identification system), and specific antigen detection (latex agglutination test). E. coli O157 were identified and confirmed in 6% (7/...

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

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

    2008-01-01

    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 industrialized 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 of interspecific bacterial transmission in a developing rural economy characterized by very close huma...

  14. Culture confirmation of Escherichia coli serotype O157:H7 by direct immunofluorescence.

    Tison, D. L.

    1990-01-01

    An evaluation of a fluorescein-labeled, polyclonal, affinity-purified goat antibody to Escherichia coli serotype O157:H7 (Kirkegaard & Perry Laboratories Inc., Gaithersburg, Md.) was conducted to determine the efficacy of this research reagent for the rapid direct immunofluorescence identification of E. coli O157:H7 isolated from fecal specimens cultured on sorbitol-MacConkey (SMAC) agar. The E. coli O157:H7 fluorescent-antibody conjugate proved to be 100% sensitive and specific for the rapid...

  15. Investigating the Antibacterial Effects of Plant Extracts on Pseudomonas aeruginosa and Escherichia coli

    Jahani

    2016-04-01

    Full Text Available Background Scientists are seeking an appropriate alternative method for curing infections caused by resistant bacteria, since drug resistance is continually increasing. Objectives This research aims to discover the function of some medicine plants on pestiferous Pseudomonas aeruginosa and Escherichia coli in humans. Materials and Methods Bacterial strains were obtained from a standard laboratory. The strains of Pseudomonas aeruginosa ATCC27853 and E.coli ATCC25922 bacteria were used for antimicrobial testing of the extractions. Results Our results showed that Teucrium polium extracts have the minimum density of inhibitory for Escherichia coli, 25 ppm, whereas the maximum of this is for Peganum harmala and Prangos ferulaceae with 100 ppm. The lowest minimum concentration inhibitory value of extracts P. harmala, T. polium, T. pratensis and Rumex was found in 25 ppm against P.aeruginosa. Conclusions The results of our study showed that plant extracts have good antibacterial properties against Pseudomonas aeruginosa and Escherichia coli.

  16. Antibiotic Resistance Patterns in Enteric and Uropathogenic Strains of Escherichia Coli in Children

    This paper should be cited as: Sedighi I, Alikhani MY, Nakhaee S, Karami P . [ Antibiotic Resistance Patterns in Enteric and Uropathogenic Strains of Escherichia Coli in Children ]. mlj goums . 201 4 ; 8 ( Suppl 4 : 42 - 48 [Article in Per sian] Sedi ghi, I. (MD

    2014-11-01

    Full Text Available Background and Objective: Escherichia coli is the most common cause of urinary tract infections in children and the leading cause of intra-abdominal infections (peritonitis and abscess followed intestinal injuries. Urinary tract infection, including cystitis and pyelonephritis, is a common childhood infection. E. coli causes more than 90 percent of the community acquired and 50% of hospital acquired urinary tract infections; therefore, the determination of E. coli antibiotic susceptibility is a paramount importance to clinical and epidemiological purposes. Material and Methods: In this cross-sectional study, 50 E. coli strains isolated from urine samples of children less than 7 years of age with urinary tract infections. They were compared for drug susceptibility testing by disc diffusion method with 50 strains of Escherichia coli isolated from stool samples of healthy children with the same age and sex pattern. Results: The actual amount of drug sensitivity of uropathogenic and intestinal Escherichia coli strains to amikacin was 94 and 100%, nitrofurantoin 90 and 88%, gentamicin 66 and 94%, cefixime 56 and 60%, nalidixic acid 38 and 44% and to cotrimoxazole 28 and 32%, respectively. Conclusion: the rate of resistance to gentamicin, Cefixime and nalidixic acid in urinary tract infection isolates were more than intestinal strains. The highest rate of drug resistance in urinary Escherichia coli isolates was associated with cotrimoxazole and the lowest one with amikacin.

  17. Molecular characterization of bacteremic Escherichia coli isolates in Romania.

    Usein, Codruţa-Romaniţa; Papagheorghe, Raluca; Oprea, Mihaela; Condei, Maria; Strãuţ, Monica

    2016-05-01

    The increasing prevalence of invasive infections caused by antibiotic resistant Escherichia coli strains in Romanian patients, already mentioned in the European reports, requires better knowledge of their specific traits. Thus, a set of 38 E. coli blood isolates, collected between 2010 and 2012 at one of the local hospitals participating into the European Antimicrobial Resistance Surveillance Network, was investigated retrospectively with respect to the phylogenetic origin, extraintestinal virulence-associated markers (i.e. fimH, papC, papG alleles, sfa/foc, afa/dra, hly, cnf1, sat, iucC, fyuA, ibeA), and beta-lactamase encoding genes (i.e. bla CTX-M, bla TEM, and bla SHV alleles). The isolates with extended-spectrum beta-lactamase (ESBL) phenotypes were further characterized using PCR-based replicon typing and multilocus sequencing typing. For ST131 members, pulsed-field gel electrophoresis (PFGE) and PCR-based detection of fimH30 allele were performed. Overall, the isolates were more likely members of the major phylogenetic group A (53 %) and to a lesser extent of groups B2 (29 %), D (10 %), and B1 (8 %). All but three of the virulence markers sought (i.e. papGI, hly, cnf1) were detected with prevalence ranging from 3 % (i.e. ibeA, papGIII) to 87 % (fimH). As expected, the most complex genotypes (four to seven virulence markers) defined the isolates derived from phylogenetic groups B2 and D. ESBL producers were bla CTX-M-15-positive, mostly of phylogroup A (67 %), harboured IncF multireplicon plasmids, and belonged to six sequence types (i.e. ST10, ST131, ST167, ST410, ST540, ST1275). Members of ST10 clonal complex (i.e. ST10, ST167) were the most common. The ST131 isolates belonged to H30 subclone and displayed 74 % similarity at PFGE analysis. PMID:26452764

  18. Reversion reactions of beta-galactosidase (Escherichia coli).

    Huber, R E; Hurlburt, K L

    1986-04-01

    The reversion reactions of beta-galactosidase (Escherichia coli) produced beta-galactosyl-galactoses and beta-galactosyl-glucoses. About 10 beta-galactosyl-galactose and 10 beta-galactosyl-glucose gas-liquid chromatographic peaks were detected and it is thus very likely that every possible isomer of beta-galactosyl-galactose and beta-galactosyl-glucose was formed by the reversion reactions (taking into account both anomers for each isomer). The presence of lactose and allolactose among the beta-galactosyl-glucoses was confirmed with standards. An important finding relating to the role of allolactose as an inducer of the lac operon was that allolactose (beta-D-galactosyl-(1----6)-D-glucose) was the only disaccharide formed initially, and at equilibrium it was present in the largest amount (50%). Obviously the enzyme is specific in its ability to form allolactose, and allolactose is the most stable beta-galactosyl-glucose, both important inducer properties. The equilibrium constant (concentration of disaccharides divided by the concentration of reactants at equilibrium) of the reaction was about 9.5 mM-1. This is the first report of an equilibrium constant for the beta-galactosidase reaction. Of mechanistic significance is the fact that only three compounds were able to replace D-galactose as a reversion reactant. Two of these (L-arabinose and D-fucose) had alterations at carbon 6. The 6 position, therefore, is not essential for reactivity. The third compound was D-galactal. Any other sugars tested (even with very minor changes relative to D-galactose) did not react. Of special consequence is the 2 position. The results strongly suggest that there has to be either an equatorial hydroxyl at the 2 position of a sugar or a special reactivity (as with D-galactal) in order for the enzyme to catalyze the beta-galactosidase reaction. PMID:3083779

  19. Electrostatic properties of two porin channels from Escherichia coli.

    Karshikoff, A; Spassov, V; Cowan, S W; Ladenstein, R; Schirmer, T

    1994-07-22

    The electrostatic interactions in the channels of OmpF and PhoE porins from Escherichia coli were analysed on the basis of a macroscopic multi-dielectric model of the protein-membrane complex derived from the respective porin X-ray structures. The membrane was represented as layers of distinct dielectric constants corresponding to the aliphatic core and the polar head groups of the lipids. The pKa values of the titratable groups and the electrostatic field in the region of the channel were calculated by the finite difference technique. In spite of the differences in sequences and charge constellations, the calculated electrostatic properties of the two porins are similar in several aspects: (1) unusual titration behaviour (pKa below 7) was found for some groups of the cluster of basic residues at the constriction of the pore; (2) a number of acidic groups buried between the internal loop and the barrel wall are stabilized in their protonated forms at neutral pH; (3) there is a strong transverse electrostatic field in the channel characterized by a screw-like form. The strength of the field is greatest at the region of the constriction zone. This would facilitate the diffusion of solutes with a large dipole moment such as free amino acids. Differences between the electrostatic fields of OmpF and PhoE are mainly confined to that end of the pore that faces the cell exterior in vivo. In OmpF the electrostatic potential is close to zero in this region of the channel, whereas a positive potential was found in PhoE. It was shown that the experimentally observed difference in ion selectivity of the two porins can largely be attributed to this distinct electrostatic property. PMID:8035460

  20. Status of vaccine research and development for enterotoxigenic Escherichia coli.

    Bourgeois, A Louis; Wierzba, Thomas F; Walker, Richard I

    2016-06-01

    Enterotoxigenic Escherichia coli (ETEC) is one of the most common bacterial causes of diarrhea-associated morbidity and mortality, particularly among infants and young children in developing countries. Still, the true impact on child and traveler health is likely underestimated. There are currently no licensed vaccines for ETEC, but studies indicate high public health impact, cost-effectiveness, and feasibility of immune protection through vaccination. ETEC vaccine development remains a World Health Organization priority. Traditionally, ETEC vaccine development efforts have focused on inducing antitoxin and anticolonization antigen immunity, as studies indicate that antibodies against both antigen types can contribute to protection and thus have potential for vaccines. Leading cellular vaccine candidates are ETVAX (a mixture of four inactivated strains) and ACE527 (a mixture of three live attenuated strains), both of which have been found to be safe and immunogenic in Phase 1/2 trials. ETVAX is the furthest along in development with descending-age studies already underway in Bangladesh. Other ETEC vaccine candidates based on protein subunits, toxoids (both LT and ST), or novel, more broadly conserved ETEC antigens are also under development. Of these, a protein adhesin-based subunit approach is the most advanced. Impact and economic models suggest favorable vaccine cost-effectiveness, which may help expand market interest in ETEC vaccines. Combination vaccine formulations may help improve the economic case for development and use, and better point-of-care diagnostics will help to raise awareness of the true health burden of ETEC and highlight the potential public health benefit of ETEC vaccine introduction. Better diagnostics and vaccine demand forecasting will also improve vaccine development financing and support accelerated uptake once a licensed vaccine becomes available. PMID:26988259

  1. The stringent response and cell cycle arrest in Escherichia coli.

    Ferullo, Daniel J; Lovett, Susan T

    2008-12-01

    The bacterial stringent response, triggered by nutritional deprivation, causes an accumulation of the signaling nucleotides pppGpp and ppGpp. We characterize the replication arrest that occurs during the stringent response in Escherichia coli. Wild type cells undergo a RelA-dependent arrest after treatment with serine hydroxamate to contain an integer number of chromosomes and a replication origin-to-terminus ratio of 1. The growth rate prior to starvation determines the number of chromosomes upon arrest. Nucleoids of these cells are decondensed; in the absence of the ability to synthesize ppGpp, nucleoids become highly condensed, similar to that seen after treatment with the translational inhibitor chloramphenicol. After induction of the stringent response, while regions corresponding to the origins of replication segregate, the termini remain colocalized in wild-type cells. In contrast, cells arrested by rifampicin and cephalexin do not show colocalized termini, suggesting that the stringent response arrests chromosome segregation at a specific point. Release from starvation causes rapid nucleoid reorganization, chromosome segregation, and resumption of replication. Arrest of replication and inhibition of colony formation by ppGpp accumulation is relieved in seqA and dam mutants, although other aspects of the stringent response appear to be intact. We propose that DNA methylation and SeqA binding to non-origin loci is necessary to enforce a full stringent arrest, affecting both initiation of replication and chromosome segregation. This is the first indication that bacterial chromosome segregation, whose mechanism is not understood, is a step that may be regulated in response to environmental conditions. PMID:19079575

  2. The stringent response and cell cycle arrest in Escherichia coli.

    Daniel J Ferullo

    2008-12-01

    Full Text Available The bacterial stringent response, triggered by nutritional deprivation, causes an accumulation of the signaling nucleotides pppGpp and ppGpp. We characterize the replication arrest that occurs during the stringent response in Escherichia coli. Wild type cells undergo a RelA-dependent arrest after treatment with serine hydroxamate to contain an integer number of chromosomes and a replication origin-to-terminus ratio of 1. The growth rate prior to starvation determines the number of chromosomes upon arrest. Nucleoids of these cells are decondensed; in the absence of the ability to synthesize ppGpp, nucleoids become highly condensed, similar to that seen after treatment with the translational inhibitor chloramphenicol. After induction of the stringent response, while regions corresponding to the origins of replication segregate, the termini remain colocalized in wild-type cells. In contrast, cells arrested by rifampicin and cephalexin do not show colocalized termini, suggesting that the stringent response arrests chromosome segregation at a specific point. Release from starvation causes rapid nucleoid reorganization, chromosome segregation, and resumption of replication. Arrest of replication and inhibition of colony formation by ppGpp accumulation is relieved in seqA and dam mutants, although other aspects of the stringent response appear to be intact. We propose that DNA methylation and SeqA binding to non-origin loci is necessary to enforce a full stringent arrest, affecting both initiation of replication and chromosome segregation. This is the first indication that bacterial chromosome segregation, whose mechanism is not understood, is a step that may be regulated in response to environmental conditions.

  3. Functions that protect Escherichia coli from DNA-protein crosslinks.

    Krasich, Rachel; Wu, Sunny Yang; Kuo, H Kenny; Kreuzer, Kenneth N

    2015-04-01

    Pathways for tolerating and repairing DNA-protein crosslinks (DPCs) are poorly defined. We used transposon mutagenesis and candidate gene approaches to identify DPC-hypersensitive Escherichia coli mutants. DPCs were induced by azacytidine (aza-C) treatment in cells overexpressing cytosine methyltransferase; hypersensitivity was verified to depend on methyltransferase expression. We isolated hypersensitive mutants that were uncovered in previous studies (recA, recBC, recG, and uvrD), hypersensitive mutants that apparently activate phage Mu Gam expression, and novel hypersensitive mutants in genes involved in DNA metabolism, cell division, and tRNA modification (dinG, ftsK, xerD, dnaJ, hflC, miaA, mnmE, mnmG, and ssrA). Inactivation of SbcCD, which can cleave DNA at protein-DNA complexes, did not cause hypersensitivity. We previously showed that tmRNA pathway defects cause aza-C hypersensitivity, implying that DPCs block coupled transcription/translation complexes. Here, we show that mutants in tRNA modification functions miaA, mnmE and mnmG cause defects in aza-C-induced tmRNA tagging, explaining their hypersensitivity. In order for tmRNA to access a stalled ribosome, the mRNA must be cleaved or released from RNA polymerase. Mutational inactivation of functions involved in mRNA processing and RNA polymerase elongation/release (RNase II, RNaseD, RNase PH, RNase LS, Rep, HepA, GreA, GreB) did not cause aza-C hypersensitivity; the mechanism of tmRNA access remains unclear. PMID:25731940

  4. Timing of Z-ring localization in Escherichia coli

    Bacterial cell division takes place in three phases: Z-ring formation at midcell, followed by divisome assembly and building of the septum per se. Using time-lapse microscopy of live bacteria and a high-precision cell edge detection method, we have previously found the true time for the onset of septation, τc, and the time between consecutive divisions, τg. Here, we combine the above method with measuring the dynamics of the FtsZ-GFP distribution in individual Escherichia coli cells to determine the Z-ring positioning time, τz. To analyze the FtsZ-GFP distribution along the cell, we used the integral fluorescence profile (IFP), which was obtained by integrating the fluorescence intensity across the cell width. We showed that the IFP may be approximated by an exponential peak and followed the peak evolution throughout the cell cycle, to find a quantitative criterion for the positioning of the Z-ring and hence the value of τz. We defined τz as the transition from oscillatory to stable behavior of the mean IFP position. This criterion was corroborated by comparison of the experimental results to a theoretical model for the FtsZ dynamics, driven by Min oscillations. We found that τz < τc for all the cells that were analyzed. Moreover, our data suggested that τz is independent of τc, τg and the cell length at birth, L0. These results are consistent with the current understanding of the Z-ring positioning and cell septation processes

  5. Escherichia coli Peritonitis in Peritoneal Dialysis: The Prevalence, Antibiotic Resistance and Clinical Outcomes in a South China Dialysis Center

    FENG, XIAORAN; Yang, Xiao; Yi, Chunyan; Guo, Qunying; Mao, Haiping; Jiang, Zongpei; Li, Zhibin; Chen, Dongmei; Cui, Yingpeng; Yu, Xueqing

    2014-01-01

    ♦ Introduction: Escherichia coli (E. coli) peritonitis is a frequent, serious complication of peritoneal dialysis (PD). The extended-spectrum β-lactamase (ESBL)-producing E. coli peritonitis is associated with poorer prognosis and its incidence has been on continuous increase during the last decades. However, the clinical course and outcomes of E. coli peritonitis remain largely unclear.

  6. Urease genes in non-O157 Shiga toxin-producing Escherichia coli : mostly silent but valuable markers for pathogenicity

    Friedrich, A W; Lukas, R; Mellmann, A; Köck, R; Zhang, W; Mathys, W; Bielaszewska, M; Karch, H

    2006-01-01

    The distribution of ureC was investigated among 294 Escherichia coli isolates, comprising 72 strains from the E. coli standard reference collection (ECOR), 62 strains from the diarrhoeagenic E. coli (DEC) collection, and 160 clinical isolates of Shiga toxin-producing E. coli (STEC). The ureC gene wa

  7. Antimicrobial effect of Satureja bachtiarica extracts aqueous and ethanolic on Escherichia coli and Staphylococcus aureus

    Maryam Heidari Sureshjani

    2013-03-01

    Full Text Available In this study antimicrobial effect of extracts evaluated by two methods, “Collins method” and “disk agar diffusion method” on Escherichia coli PTCC 1330 and Staphylococcus aureus PTCC 1337 microorganisms. The minimum inhibitory concentration (MIC and minimum bactericidal concentration (MBC for both species determined by using a dilution method. All ethanolic extract concentrations had inhibitory effect in the disk agar diffusion method. In “Collins method” ethanolic extract in 2000 µg/ml concentration, could prevent the growth of both strains on medium. The aqueous extract, had no antimicrobial significant effect in 2000 µg/ml concentration. The ethanolic extract MIC of Satureja bachtiarica for Staphylococcus aureus was 8 mg/ml, and for Escherichia coli was 16 mg/ml. But the aqueous extracts MIC of Satureja bachtiarica for Staphylococcus aureus was 32 mg/ml and for Escherichia coli was 64 mg/ml. The ethanolic extract MBC of Satureja bachtiarica for Staphylococcus aureus was 16 mg/ml, and for Escherichia coli was 32 mg/ml. But the aqueous extracts MBC of Satureja bachtiarica for Staphylococcus aureus was 64 mg/ml and for Escherichia coli was 256 mg/ml. The results indicate that ethanolic extract of Satureja bachtiarica have the greatest effect on gram positive bacterium Staphylococcus aureus PTCC 1337. 

  8. Novel Model To Study Virulence Determinants of Escherichia coli K1▿

    Khan, Naveed Ahmed; Goldsworthy, Graham John

    2007-01-01

    It is shown here for the first time that locusts can be used as a model to study Escherichia coli K1 pathogenesis. E. coli K-12 strain HB101 has very low pathogenicity to locusts and does not invade the locust brain, whereas the injection of 2 × 106 E. coli K1 strain RS218 (O18:K1:H7) kills almost 100% of locusts within 72 h and invades the brain within 24 h of injection. Both mortality and invasion of the brain in locusts after injection of E. coli K1 require at least two of the known virule...

  9. Radiocomplexation and evaluation of the 99mTc-Gemifloxacin in artificially Escherichia coli infected mice

    Gemifloxacin as a broad spectrum quinolone antibacterial agent was radiocomplexed with high activity of 99mTc and was evaluated as an infection imaging agent in artificially Escherichia coli (E. Coli) infected mice. 99mTc-Gemifloxacin with high specific activity (0.148 GBq/μmol) and labeling yield (98.60 ± 0.70 %) was obtained. Our main achievement was high accumulation in the E. Coli infected right thigh muscle in mice (T/NT = 1.89 at 4 h post injection) which may diagnostically be beneficial to distinguish sites of E. Coli infection. (author)

  10. Metabolic Engineering of a 1,2-Propanediol Pathway in Escherichia coli

    Altaras, Nedim E.; Cameron, Douglas C.

    1999-01-01

    1,2-Propanediol (1,2-PD) is a major commodity chemical that is currently derived from propylene, a nonrenewable resource. A goal of our research is to develop fermentation routes to 1,2-PD from renewable resources. Here we report the production of enantiomerically pure R-1,2-PD from glucose in Escherichia coli expressing NADH-linked glycerol dehydrogenase genes (E. coli gldA or Klebsiella pneumoniae dhaD). We also show that E. coli overexpressing the E. coli methylglyoxal synthase gene (mgs) ...

  11. Determination of plasmid DNA concentration maintained by nonculturable Escherichia coli in marine microcosms.

    Byrd, J J; Leahy, J G; Colwell, R. R.

    1992-01-01

    The concentration of plasmid pBR322 DNA in nonculturable Escherichia coli JM83 was measured to determine whether the plasmid concentration changed during survival of E. coli in marine and estuarine water. E. coli JM83 containing the plasmid pBR322 was placed in both sterile seawater and sterile estuarine water and analyzed for survival (i.e., culturability) and plasmid maintenance. The concentration of pBR322 DNA remained stable in E. coli JM83 for 28 days in an artificial seawater microcosm,...

  12. Escherichia coli O157:H7 - An Emerging Pathogen in foods of Animal Origin

    Ch. Bindu Kiranmayi

    Full Text Available Escherichia coli O157:H7 is an emerging public health concern in most countries of the world. E. coli O157:H7 was known to be a human pathogen for nearly 24 years. EHEC O157 infection is estimated to be the fourth most costly food borne disease in Canada and USA, not counting the cost of possible litigation. E. coli O157:H7 and Salmonella are the leading causes of produce related outbreaks, accounting for 20 and 30% respectively. The authority of the Federal Meat Inspection Act, FSIS (Food Safety and Inspection Service declared Escherichia coli O157:H7, an adulterant in raw ground beef and enforced “zero tolerance” (USDA-FSIS, 17 December 1998. Because of the severity of these illnesses and the apparent low infective dose (less than 10 cells, Escherichia coli O157:H7 is considered one of the most serious of known food borne pathogens. Escherichia coli O157:H7 is mainly pathogenic to human but in cattle and other animals, it did not induce any clinical disease except diarrhea. So, these animals act as carriers to Escherichia coli O157:H7. The majority transmission is through eating of undercooked contaminated ground meat and consumption of raw milk, raw vegetables, fruits contaminated by water, cheese, curd and also through consumption of sprouts, lettuce and juice. The conventional isolation procedure includes growth in enrichment broth like modified EC (E. coli broth or modified tryptic soy broth (mTSB Since the infection primarily occurs via faeco-oral route, the preventive measures include food hygiene measures like proper cooking of meat, consumption of pasteurized milk, washing fruits and vegetables especially those to be eaten raw and drinking chlorine treated water and personnel hygiene measures like washing hands after toilet visits. [Veterinary World 2010; 3(8.000: 382-389

  13. Cytotoxic Necrotizing Factor 1 Contributes to Escherichia coli Meningitis

    Ming-Hsien Wang

    2013-11-01

    Full Text Available E. coli is the most common Gram-negative bacteria causing neonatal meningitis, and E. coli meningitis continues to be an important cause of mortality and morbidity throughout the world. Recent reports of E. coli meningitis caused by antimicrobial resistant strains are a particular concern. These findings indicate that a novel strategy is needed to identify new targets for prevention and therapy of E. coli meningitis. Cytotoxic necrotizing factor 1 (CNF1 is a bacterial virulence factor associated principally with E. coli strains causing urinary tract infection and meningitis. We have shown that CNF1 contributes to E. coli invasion of the blood-brain barrier and penetration into the brain, the essential step in the development of E. coli meningitis, and identified the host receptor for CNF1, 37-kDa laminin receptor precursor (37LRP. CNF1, however, is a cytoplasmic protein and its contribution to E. coli invasion of the blood-brain barrier requires its secretion from the bacterial cytoplasm. No signal peptide is found in the CNF1 sequence. CNF1 secretion is, therefore, a strategy utilized by meningitis-causing E. coli to invade the blood-brain barrier. Elucidation of the mechanisms involved in CNF1 secretion, as shown in this report with the involvement of Fdx and YgfZ provides the novel information on potential targets for prevention and therapy of E. coli meningitis by virtue of targeting the secretion of CNF1.

  14. Modeling the inactivation of Escherichia coli 0157:H7 and uropathogenic E.coli in ground chicken by high pressure processing and thymol

    Disease causing Escherichia coli commonly found in meat and poultry include intestinal pathogenic E. coli (iPEC) as well as extraintestinal types such as the Uropathogenic E. coli (UPEC). In this study we compare the resistance of iPEC (O157:H7) to UPEC in chicken meat using High Pressure Processing...

  15. Development of a Vaccine against Escherichia coli Urinary Tract Infections.

    Mobley, Harry L T; Alteri, Christopher J

    2015-01-01

    Urinary tract infection (UTI) is the second most common infection in humans after those involving the respiratory tract. This results not only in huge annual economic costs, but in decreased workforce productivity and high patient morbidity. Most infections are caused by uropathogenic Escherichia coli (UPEC). Antibiotic treatment is generally effective for eradication of the infecting strain; however, documentation of increasing antibiotic resistance, allergic reaction to certain pharmaceuticals, alteration of normal gut flora, and failure to prevent recurrent infections represent significant barriers to treatment. As a result, approaches to prevent UTI such as vaccination represent a gap that must be addressed. Our laboratory has made progress toward development of a preventive vaccine against UPEC. The long-term research goal is to prevent UTIs in women with recurrent UTIs. Our objective has been to identify the optimal combination of protective antigens for inclusion in an effective UTI vaccine, optimal adjuvant, optimal dose, and optimal route of delivery. We hypothesized that a multi-subunit vaccine elicits antibody that protects against experimental challenge with UPEC strains. We have systematically identified four antigens that can individually protect experimentally infected mice from colonization of the bladder and/or kidneys by UPEC when administered intranasally with cholera toxin (CT) as an adjuvant. To advance the vaccine for utility in humans, we will group the individual antigens, all associated with iron acquisition (IreA, Hma, IutA, FyuA), into an effective combination to establish a multi-subunit vaccine. We demonstrated for all four vaccine antigens that antigen-specific serum IgG represents a strong correlate of protection in vaccinated mice. High antibody titers correlate with low colony forming units (CFUs) of UPEC following transurethral challenge of vaccinated mice. However, the contribution of cell-mediated immunity cannot be ruled out and

  16. Effect of zinc in enteropathogenic Escherichia coli infection.

    Crane, John K; Naeher, Tonniele M; Shulgina, Irina; Zhu, Chengru; Boedeker, Edgar C

    2007-12-01

    Enteropathogenic Escherichia coli (EPEC) infection triggers the release of ATP from host intestinal cells, and the ATP is broken down to ADP, AMP, and adenosine in the lumen of the intestine. Ecto-5'-nucleotidase (CD73) is the main enzyme responsible for the conversion of 5'-AMP to adenosine, which triggers fluid secretion from host intestinal cells and also has growth-promoting effects on EPEC bacteria. In a recent study, we examined the role of the host enzyme CD73 in EPEC infection by testing the effect of ecto-5'-nucleotidase inhibitors. Zinc was a less potent inhibitor of ecto-5'-nucleotidase in vitro than the nucleotide analog alpha,beta-methylene-ADP, but in vivo, zinc was much more efficacious in preventing EPEC-induced fluid secretion in rabbit ileal loops than alpha,beta-methylene-ADP. This discrepancy between the in vitro and in vivo potencies of the two inhibitors prompted us to search for potential targets of zinc other than ecto-5'-nucleotidase. Zinc, at concentrations that produced little or no inhibition of EPEC growth, caused a decrease in the expression of EPEC protein virulence factors, such as bundle-forming pilus (BFP), EPEC secreted protein A, and other EPEC secreted proteins, and reduced EPEC adherence to cells in tissue culture. The effects of zinc were not mimicked by other transition metals, such as manganese, iron, copper, or nickel, and the effects were not reversed by an excess of iron. Quantitative real-time PCR showed that zinc reduced the abundance of the RNAs encoded by the bfp gene, by the plasmid-encoded regulator (per) gene, by the locus for the enterocyte effacement (LEE)-encoded regulator (ler) gene, and by several of the esp genes. In vivo, zinc reduced EPEC-induced fluid secretion into ligated rabbit ileal loops, decreased the adherence of EPEC to rabbit ileum, and reduced histopathological damage such as villus blunting. Some of the beneficial effects of zinc on EPEC infection appear to be due to the action of the metal on

  17. Ileal adhesion of virulent E. coli LF82 is not enhanced in Crohn’s disease

    Jensen, Rikke S.; Fink, Lisbeth Nielsen; Pedersen, Susanne Brix; Brynskov, J.; Nielsen, Haagen O.

    2011-01-01

    . A second purpose was to assess the probiotic efficacy of E. coli Nissle 1917 (ECN) in averting LF82 adhesion to ileal mucosa. Ileal and colonic specimens were obtained from patients with CD ileitis and controls (n¼10). A model was developed to investigate bacterial adhesion to intestinal biopsies......Adherent-invasive Escherichia coli (AIEC) comprise a new group of E. coli species named from their distinctive ability to adhere to and invade the intestinal epithelium. The AIEC strains have been associated to the ileal mucosa in Crohn’s disease (CD), and the impact of AIEC in the pathogenesis of...... CD has been further strengthened from the evidence that the ileum in CD harbors an abnormally high number of E. coli species. S16 2010 IBD Abstracts The aim of this study was to examine the adhesion of the AIEC reference strain, LF82, to tissue samples from ileum and colon in CD and healthy controls...

  18. Antibody specific for Escherichia coli J5 cross-reacts to various degrees with an Escherichia coli clinical isolate grown for different lengths of time.

    McCallus, D E; Norcross, N. L.

    1987-01-01

    Rabbit antiserum raised against the rough mutant of Escherichia coli O111:B4, designated J5, was examined for cross-reactivity to an E. coli clinical isolate (A2385). In whole-cell enzyme-linked immunosorbent assays, J5 antiserum reacted to a greater extent with A2385 grown for 5 h than with the same bacteria grown for 19 h, while the homologous antiserum reacted similarly with bacteria grown for different lengths of time. J5 antiserum reacted to the greatest extent with lipopolysaccharide (L...

  19. Multirresistência antimicrobiana em cepas de Escherichia coli isoladas de cadelas com piometra Antimicrobial multi-resistance of Escherichia coli strains isolated from bitches with pyometra

    V.M. Lara

    2008-08-01

    Full Text Available The antimicrobial sensibility of Escherichia coli strains isolated from the uterine content of bitches was evaluated. Fifteen E. coli strains were tested in relation to their susceptibility to different antimicrobials. The results demonstrated 100% of resistance to all tested drugs, being a quite conflicting finding compared to other works, which observed variable resistance of those bacteria to different antimicrobials but not the same multi-resistance pattern. The detection of those multi-resistance strains configures a problem, with important implications on the antimicrobial therapy. Therefore, additional investigations for a best characterization and extension of this problem are needed.

  20. Antimicrobial resistance among Escherichia coli that cause childhood community-acquired urinary tract infections in Northern Italy

    Caracciolo Alessandra; Bettinelli Alberto; Bonato Claudio; Isimbaldi Clementina; Tagliabue Alessandro; Longoni Laura; Bianchetti Mario G

    2011-01-01

    Abstracts Background Resistance rate of Escherichia coli against antimicrobials that are commonly prescribed in pediatric urinary tract infections is currently a matter of concern. Methods The antimicrobial susceptibility patterns of uropathogenic Escherichia coli strains to the common antibimcrobials ampicillin, cotrimoxazole, coamoxyclav, ceftazidime, ceftriaxone, nitrofurantoin, and gentamycin were determined in 177 children aged from 2 to 36 months. They presented with their first symptom...

  1. Konstruktie van plasmiden met genen van het tryptofaan operon van Escherichia coli K12 als genetische kenmerken

    Enger-Valk, B.E.

    1981-01-01

    Chapter 1CONSTRUCTION OF NEW CLONING VEHICLES WITH GENES OF THETRYPTOPHAN OPERON OF Escherichia coli AS GENETIC MARKERSIn vitro recombination techniques were used to construct a series of new cloning vehicles with genes of the tryptophan (trp) operon of Escherichia coli as selective marker. To const

  2. Infektionsprophylaxe mit Escherichia coli Stamm Nissle 1917 bei Frühgeborenen unter 1500 g

    Blümlein, Ulrike

    2012-01-01

    The main question of this study was, if prophylactic treatment with Escherichia coli strain Nissle 1917 helps to prevent infection in VLBW infants. Because of different limitations of this pilot study this issue can not be entirely clarified. The study illustrates the influence of Escherichia coli strain Nissle 1917 (EcN) on the clinical course of VLBW infants: The treatment with EcN was indifferent for the weight increase between the 10th and 30th day of life. One can not rule out the possib...

  3. Heat-labile enterotoxigenic Escherichia coli and intestinal protozoa in asymptomatic travellers.

    Echeverria, P; Cross, J H

    1977-12-01

    Thirty-two asymptomatic travellers who had recently journeyed in the Near, Middle, and Far East and had experienced a high incidence of diarrhoeal disease were screened for heat-labile enterotoxigenic Escherichia coli (ent+ E. coli) and other bacterial and parasitic pathogens. Six percent were colonized with ent+ E. coli and while other bacterial pathogens were not found, the intestinal protozoa Giardia lamblia (13%), Entamoeba histolytica (6%), Entamoeba coli (6%), Endolimax nana (6%), and Entamoeba hartmanni (3%) were detected in the stools. Ent+ E. coli, G. lamblia and E. histolytica should be considered in the differential diagnosis of gastrointestinal disease in travellers returning from the Orient. Furthermore, these travellers may be a potential source for the introduction of ent+ E. coli into communities where such organisms are relatively rare. PMID:351820

  4. Intestinal colonization with phylogenetic group B2 Escherichia coli related to inflammatory bowel disease

    Petersen, Andreas Munk; Halkjær, Sofie Ingdam; Gluud, Lise Lotte

    2015-01-01

    on 163 patients with IBD and 89 controls. Among IBD patients, 57 patients had ulcerative colitis (UC) and 95 Crohn's disease (CD). Random-effects meta-analysis showed that IBD patients were more likely to have B2 E. coli intestinal colonization compared with controls (odds ratio [OR]: 2.28; 95......BACKGROUND AND OBJECTIVES: Increased numbers of Escherichia coli and, furthermore, specific subtypes of E. coli, such as E. coli of the phylogenetic groups B2 and D have been found in the intestine of patients with inflammatory bowel disease (IBD). In this review, we wanted to evaluate the...... relationship between B2 and D E. coli intestinal colonization and IBD. METHODS: A systematic review with meta-analyses. We included studies comparing colonization with B2 and D E. coli in IBD patients and in controls. Random-effects and fixed-effect meta-analyses were performed. RESULTS: We included 7 studies...

  5. Expansion of Shiga Toxin–Producing Escherichia coli by Use of Bovine Antibiotic Growth Promoters

    Kim, Jong-Chul; Chui, Linda; Wang, Yang; Shen, Jianzhong

    2016-01-01

    Antibiotics are routinely used in food-producing animals to promote growth and prevent infectious diseases. We investigated the effects of bovine antibiotic growth promoters (bAGPs) on the propagation and spread of Shiga toxin (Stx)–encoding phages in Escherichia coli. Co-culture of E. coli O157:H7 and other E. coli isolated from cattle in the presence of sublethal concentrations of bAGPs significantly increased the emergence of non-O157, Stx-producing E. coli by triggering the SOS response system in E. coli O157:H7. The most substantial mediation of Stx phage transmission was induced by oxytetracyline and chlortetracycline, which are commonly used in agriculture. bAGPs may therefore contribute to the expansion of pathogenic Stx-producing E. coli. PMID:27088186

  6. Escherichia coli clonal group A causing bacteraemia of urinary tract origin

    Skjøt-Rasmussen, L; Olsen, S S; Jakobsen, L;

    2013-01-01

    practice and a CgA isolate from a community-dwelling human reported previously, was found, suggesting a community origin of CgA. The finding of CgA strains in 15% of the E. coli bloodstream infections with a urinary tract origin in Denmark suggests that CgA constitutes an important clonal lineage among...... extraintestinal pathogenic E. coli. A reservoir of this pathogenic E. coli group in the community causing not only UTI but also more severe infections such as bacteraemia has implications for public health.......Clin Microbiol Infect ABSTRACT: Escherichia coli clonal group A (CgA) causes disease in humans. This is the first study investigating the prevalence of CgA among E. coli from non-urine, extraintestinal infections in a northern European country. E. coli blood (n = 196) and paired urine (n = 195...

  7. Production and characterisation of monoclonal antibodies specific for Escherichia coli O157:H7.

    Luciani, M; Armillotta, G; Magliulo, M; Portanti, O; Di Febo, T; Di Giannatale, E; Roda, A; Lelli, R

    2006-01-01

    Seven monoclonal antibodies (MAbs) specific for Escherichia coli O157:H7, one of the major causes of haemorrhagic colitis in humans, were produced by immunising Balb/c mice with the strain E. coli O157:H7. These monoclonal antibodies do not cross-react with other bacteria such as Salmonella enterica serovar Typhimurium, E. coli O14, E. coli JM109, S. enterica serovar Enteritidis, S. panama, S. saintpaul, S. derby, S. muenchen, S. bredeney, S. hadar, Yersinia enterocolitica, Proteus vulgaris, Shigella flexneri, Listeria ivanovii, L. monocytogenes 13M, L. innocua, Enterobacter cloacae, E. agglomerans, E. amnigenus, Citrobacter freundii, Escherichia fergussoni or Klebsiella pneumoniae. Of the seven MAbs obtained, MAb 8B8C3 was selected to prepare a high-sensitivity sandwich ELISA method specific for O157:H7. PMID:20429059

  8. Characterization of Escherichia coli isolated from migratory water fowls in Hakaluki Haor, Bangladesh

    Ferdaus MohdAltaf Hossain

    2012-03-01

    Full Text Available A total of 135 fecal samples were collected to characterize the Escherichia coli isolates from the migratory waterfowls (whistling Swan harbored in the Hakaluki Haor of Bangladesh in the year of 2008 and 2009. Out of 135 fecal samples, 100 samples were distinguished as positive for isolates of Escherichia coli following cultural, biochemical and motility test. Amongst the recovered isolates only 38% were found upbeat to enterotoxin production propensity on mice inoculation test. Finally, out of 38 % enterotoxigenic E. coli (ETEC positive isolates no any isolates found to be positive for the aptitude of heat stable (ST toxin yield. So, the presence of ETEC in migratory waterfowls indicating the possibilities of them to act as vector and reservoir of E. coli to spread further infection to animals and humans. This work indicates the first time ETEC characterization from the migratory birds of Bangladesh.

  9. Molecular detection and antimicrobial resistance of diarrheagenic Escherichia coli strains isolated from diarrheal cases

    Objective was to identify and classify Iranian isolates of diarrheagenic Escherichia coli (E. coli) on the basis of presence of virulence genes and to determine antibiotic susceptibility of isolated strains. The current cross-sectional study was conducted in 2005 at the Pasteur Institute, Tehran, Iran. One hundred and ninety-three diarrheagenic E. coli isolated from diarrheal patients in different regions of Iran were included in current study. Virulence factors genees for diarrheagenic E. coli were detected by polymerase chain reaction. Of the 193 diarrheagenic E. coli detected by PCR, 86(44.5%) were Shiga toxin-producing E. coli (STEC), 74 (38.4%) enteropathogenic E. coli (EPEC), 19 (9.8%) enteroaggregative E. coli and 14 (7.3%) enterotoxigenic E. coli isolates. Susceptibility to 12 clinically important antimicrobial agents was determined for 193 strains of diarrhheagenic E. coli. A high incidence of resistance to tetracycline (63%), ampicillin (62%), streptomycin (56%), amoxicillin/clavulanic acid (44.5%), trimetoprim/sulphamethoxazole (39.5%) and cephalothin (37%) was observed. The STEC and EPEC strains with high resistance to tetracycline and ampicillin but highly susceptible to quinolones are among the most important causative agent of diarrhea in Iran. This study suggests that antimicrobial resistance is wide spread among E. coli strains colonizing Iranian patients. Guidelines for appropriate use of antibiotics in developing countries require updating. (author)

  10. Prevalencia de Escherichia coli enterohemorrágica en terneros lactantes de ganado lechero (Prevalence of enterohemorrhagic Escherichia coli in nursling calves of dairy cattle

    Cepero Rodríguez, Omelio

    2011-02-01

    Full Text Available ResumenSe determinó la prevalencia de Escherichia coli enterohemorrágica en una muestra de 52 terneros lactantes de cuatro rebaños lecheros pertenecientes a dos localizaciones geográficas (A y B de una empresa pecuaria de la provincia de Villa Clara, Cuba. Los resultados demostraron una alta prevalencia de aislamientos positivos (42,3 y 38,5% en “A” y “B” respectivamente sin diferencias significativas entre los rebaños.SummaryIt was determined the prevalence of enterohemorrhagic Escherichia coli in a sample of 52 nursling calves of four dairy flocks belonging to two geographical localizations (A, B of a cattle company of Villa Clara province, Cuba.

  11. Contribution of Escherichia coli Alpha-Hemolysin to Bacterial Virulence and to Intraperitoneal Alterations in Peritonitis

    May, Addison K; Gleason, Thomas G.; Sawyer, Robert G.; Pruett, Timothy L.

    2000-01-01

    Alpha-hemolysin (Hly) is a common exotoxin produced by Escherichia coli that enhances virulence in a number of clinical infections. The addition of hemolysin production to laboratory bacterial strains is known to increase the lethality of E. coli peritonitis. However, the mechanisms involved have not been determined and the contribution of hemolysin to the alterations in the host intraperitoneal environment and the leukocyte response is not known. Utilizing a rat peritonitis model, we show th...

  12. Transkriptomanalyse von Escherichia coli unter Kohlenhydrat-Limitierung mittels DNA-Microarrays

    Lemuth, Karin

    2006-01-01

    Escherichia coli weist unter Glukose-Limitierung (Konzentrationen unter 0,05 g/L) zahlreiche physiologische Veränderungen auf. Man unterscheidet die ppGpp-vermittelte Stringente Kontrolle, die cAMP/CRP-vermittelte Hungerantwort, die Cra-vermittelte Antwort zur Anpassung des Kohlenstoffflusses sowie die sogenannte "Starvation". Eine eindeutige Differenzierung der verschiedenen Stressantworten in E. coli unter Glukose-Limitierung sowie deren zeitliche Zuordnung ist bisher aufgrund methodisch...

  13. Virulence versus fitness determinants in Escherichia coli isolated from asymptomatic bacteriuria in healthy nonpregnant women

    Sugandha Srivastava; Jyotsna Agarwal; Bharti Mishra; Richa Srivastava

    2016-01-01

    Purpose: Escherichia coli isolated from asymptomatic bacteriuria (ABU) correlated genotypically and phenotypically with cystitis isolates may help in distinguishing urovirulence determinants from 'fitness factors', latter necessary only for survival of E. coli in urinary tract; for gaining insight into the pathogenesis of urinary tract infection. Materials and Methods: In this cross-sectional study, we compared genotypic (phylogroups and 15 putative virulence genes), and phenotypic profiles o...

  14. Genotoxicity of Escherichia coli Nissle 1917 strain cannot be dissociated from its probiotic activity

    Olier, Maïwenn; Marcq, Ingrid; Salvador-Cartier, Christel; Secher, Thomas; Dobrindt, Ulrich; Boury, Michèle; Bacquié, Valérie; Penary, Marie; Gaultier, Eric; Nougayrède, Jean-Philippe; Fioramonti, Jean; Oswald, Eric

    2012-01-01

    Oral administration of the probiotic bacterium Escherichia coli Nissle 1917 improves chronic inflammatory bowel diseases, but the molecular basis for this therapeutic efficacy is unknown. E. coli Nissle 1917 harbors a cluster of genes coding for the biosynthesis of hybrid nonribosomal peptide-polyketide(s). This biosynthetic pathway confers the ability for bacteria to induce DNA double strand breaks in eukaryotic cells. Here we reveal that inactivation of the clbA gene within this genomic isl...

  15. Characterization of Escherichia coli colonizing the gastrointestinal tract and urinary tract catheters

    Wang, Xiaoda

    2008-01-01

    Commensal and pathogenic bacteria express biofilm behaviour which is thought to alter bacteria-host interactions and contribute to colonization and persistence. In the current thesis, the epidemiology of biofilm formation in gastrointestinal commensal Escherichia coli and E. coli isolated from urinary catheters is described. Further on, in selected commensal isolates the impact of biofilm formation on the interaction with a gastrointestinal epithelial cell line is investigat...

  16. Draft Genome Sequence of Escherichia coli Strain Nissle 1917 (Serovar O6:K5:H1)

    Cress, Brady F.; Linhardt, Robert J.; Koffas, Mattheos A. G.

    2013-01-01

    We announce the availability of the 5.023-Mbp high-quality draft assembly of the Escherichia coli strain Nissle 1917 (serovar O6:K5:H1) genome. Short genomic segments from this important probiotic strain have been available in public databases, but the full genome sequence has remained inaccessible. Thus, high-coverage, whole genome sequencing of E. coli Nissle 1917 is presented herein. Reannotation and metabolic reconstruction will enable comparative genomics analysis and model-guided predic...

  17. Differential Effects of Replacing Escherichia coli Ribosomal Protein L27 with Its Homologue from Aquifex aeolicus

    Maguire, Bruce A.; Manuilov, Anton V; Zimmermann, Robert A.

    2001-01-01

    The rpmA gene, which encodes 50S ribosomal subunit protein L27, was cloned from the extreme thermophile Aquifex aeolicus, and the protein was overexpressed and purified. Comparison of the A. aeolicus protein with its homologue from Escherichia coli by circular dichroism analysis and proton nuclear magnetic resonance spectroscopy showed that it readily adopts some structure in solution that is very stable, whereas the E. coli protein is unstructured under the same conditions. A mutant of E. co...

  18. Increasing the Oxidative Stress Response Allows Escherichia coli To Overcome Inhibitory Effects of Condensed Tannins

    Smith, Alexandra H.; Imlay, James A.; Mackie, Roderick I.

    2003-01-01

    Tannins are plant-derived polyphenols with antimicrobial effects. The mechanism of tannin toxicity towards Escherichia coli was determined by using an extract from Acacia mearnsii (Black wattle) as a source of condensed tannins (proanthocyanidins). E. coli growth was inhibited by tannins only when tannins were exposed to oxygen. Tannins auto-oxidize, and substantial hydrogen peroxide was generated when they were added to aerobic media. The addition of exogenous catalase permitted growth in ta...

  19. The Indole Pulse: A New Perspective on Indole Signalling in Escherichia coli

    Hannah Gaimster; Jehangir Cama; Silvia Hernández-Ainsa; Keyser, Ulrich F.; Summers, David K.

    2014-01-01

    Indole has diverse signalling roles, including modulation of biofilm formation, virulence and stress responses. Changes are induced by indole concentrations of 0.5-1.0 mM, similar to those found in the supernatant of Escherichia coli stationary phase culture. Here we describe an alternative mode of indole signalling that promotes the survival of E. coli cells during long-term stationary phase. A mutant that has lost the ability to produce indole demonstrates reduced survival under these condi...

  20. Neem (Azadirachta indica A. Juss) Oil to Tackle Enteropathogenic Escherichia coli

    Paola Del Serrone; Chiara Toniolo; Marcello Nicoletti

    2015-01-01

    Neem (Azadirachta indica A. Juss) oil (NO) was assayed against forty-eight isolates of Escherichia coli by standardised disc diffusion test and microdilution test. By molecular biology characterization, fourteen isolates resulted in diarrheagenic E. coli with sixteen primer pairs that specifically amplify unique sequences of virulence genes and of 16S rRNA. The NO showed biological activity against all isolates. The bacterial growth inhibition zone by disc diffusion method (100 µL NO) ranged ...

  1. P-antigen-recognizing fimbriae from human uropathogenic Escherichia coli strains.

    Korhonen, T K; Väisänen, V; Saxén, H; Hultberg, H.; Svenson, S B

    1982-01-01

    P-antigen-recognizing fimbriae (P fimbriae) from four pyelonephritogenic Escherichia coli strains and type 1 fimbriae from an E. coli strain and a Salmonella typhimurium strain were purified. The P fimbriae were morphologically similar to type 1 fimbriae. The purified P fimbriae agglutinated neuraminidase-treated human P1 and P2k erythrocytes but not p erythrocytes, which lack all P-blood group-specific glycosphingolipids. However, coating of neuraminidase-treated p erythrocytes with globosid...

  2. Ability of Escherichia coli isolates that cause meningitis in newborns to invade epithelial and endothelial cells.

    Meier, C.; Oelschlaeger, T A; Merkert, H; Korhonen, T K; Hacker, J

    1996-01-01

    Escherichia coli isolates that cause meningitis in newborns are able to invade the circulation and subsequently cross the blood-brain barrier. One mechanism for traversing the blood-brain barrier might involve transcytosis through the endothelial cells. The ability of the meningitis isolate E. coli IHE3034, of serotype 018:K1:H7, to invade epithelial (T24) and endothelial (EA-hy926) cells was investigated by the standard gentamicin survival assay and by electron microscopy. Human bladder epit...

  3. Vicinal Dithiol-Disulfide Distribution in the Escherichia coli Mannitol Specific Carrier Enzyme IImtl

    Roossien, F.F.; Robillard, G. T.

    1984-01-01

    Escherichia coli mannitol specific EII in membrane vesicles can be inhibited by the action of the oxidizable substrate-reduced phenazine methosulfate (PMS) in a manner similar to E. coli enzyme IIGlc. The fact that reduced PMS and various oxidizing agents protect the enzyme from inactivation by the sulfhydryl reagents N-ethylmaleimide and bromopyruvate suggests that the active form possesses a dithiol which can be protected by conversion to a disulfide. The sulfhydryl-disulfide distribution h...

  4. Phenotypic and Molecular Characterization of Extended-Spectrum Beta-Lactamase-Producing Escherichia coli in Bangladesh

    Lina, Taslima T.; Khajanchi, Bijay K.; Azmi, Ishrat J.; Mohammad Aminul Islam; Belal Mahmood; Mahmuda Akter; Atanu Banik; Rumana Alim; Armando Navarro; Gabriel Perez; Alejandro Cravioto; Talukder, Kaisar A

    2014-01-01

    BACKGROUND: Resistance to cephalosporins in Enterobacteriaceae is mainly due to the production of extended-spectrum beta-lactamase (ESBL). Little is known about ESBL-producing bacteria in Bangladesh. Therefore, the study presents results of phenotypic and molecular characterization of ESBL-producing Escherichia coli from hospitals in Bangladesh. METHODS: A total of 339 E. coli isolated from patients with urinary tract and wound infections attending three different medical hospitals in urban a...

  5. Characterization of Escherichia coli Phylogenetic Groups Associated with Extraintestinal Infections in South Indian Population

    Chakraborty, A.; Saralaya, V; Adhikari, P; Shenoy, S.; Baliga, S.; A Hegde

    2015-01-01

    Background: Escherichia coli strains mainly fall into four phylogenetic groups (A, B1, B2, and D) and that virulent extra-intestinal strains mainly belong to groups B2 and D. Aim: The aim was to determine the association between phylogenetic groups of E. coli causing extraintestinal infections (ExPEC) regarding the site of infection, expression of virulence factors, antimicrobial resistance patterns, and clinical outcome. This descriptive study was carried out in a multi-specialty Tertiary Ca...

  6. Heterologous production of polyketides by modular type I polyketide synthases in Escherichia coli

    Yuzawa, S; Kim, W; Katz, L; Keasling, JD

    2012-10-01

    Heterologous production of polyketide compounds, an important class of natural products with complex chemical structures, was first demonstrated with Streptomyces parvulus in 1984. Although Streptomyces strains are good first options for heterologous polyketide biosynthesis, their slow growth kinetics prompt other hosts to also be considered. Escherichia coli provides key elements of an ideal host in terms of the growth rate, culture conditions, and available recombinant DNA tools. Here we review the current status and potential for metabolic engineering of polyketides in E. coli.

  7. No Development of Imipenem Resistance in Pneumonia Caused by Escherichia coli

    Yayan, Josef; Ghebremedhin, Beniam; Rasche, Kurt

    2015-01-01

    Background: Antibiotic resistance continues to rise due to the increased number of antibiotic prescriptions and is now a major threat to public health. In particular, there is an increase in antibiotic resistance to Escherichia coli according to the latest reports. Trial Design: This article examines, retrospectively, antibiotic resistance in patients with community- and nosocomial-acquired pneumonia caused by E coli. Methods: The data of all patients with community- and nosocomial-acquired p...

  8. Isolation, characterization, and mode of action on Escherichia coli strains of microcin D93.

    Martínez, J. L.; Pérez-Díaz, J C

    1986-01-01

    Microcin D93 is an antibiotic substance produced by Escherichia coli strains which harbor the 5.5-kilobase plasmid pMccD93. Its production is unaffected by the use of different carbon and ammonia sources, different phosphate concentrations, or mitomycin C. We developed a method for purifying this microcin based on gel permeation chromatography and reverse-phase high-pressure liquid chromatography. The antibiotic appears to be a small, hydrophilic, basic peptide, active on E. coli and Proteus,...

  9. Role of outer membrane barrier in efflux-mediated tetracycline resistance of Escherichia coli.

    Thanassi, D. G.; Suh, G S; Nikaido, H

    1995-01-01

    Accumulation of tetracycline in Escherichia coli was studied to determine its permeation pathway and to provide a basis for understanding efflux-mediated resistance. Passage of tetracycline across the outer membrane appeared to occur preferentially via the porin OmpF, with tetracycline in its magnesium-bound form. Rapid efflux of magnesium-chelated tetracycline from the periplasm was observed. In E. coli cells that do not contain exogenous tetracycline resistance genes, the steady-state level...

  10. Prevalence and diversity of enterotoxigenic Escherichia coli strains in fresh produce.

    Feng, Peter C H; Reddy, Shanker P

    2014-05-01

    Analysis of fresh produce showed that enterotoxigenic Escherichia coli (ETEC) strains are most often found in cilantro and parsley, with prevalence rates of approximately 0.3%. Some ETEC strains also carried Shiga toxigenic E. coli (STEC) genes but had no STEC adherence factors, which are essential to cause severe human illness. Most ETEC strains in produce carried stable toxin and/or labile toxin genes but belonged to unremarkable serotypes that have not been reported to have caused human illnesses. PMID:24780338

  11. Modelling of Escherichia coli Cultivations: Acetate Inhibition in a Fed-batch Culture

    Stoyan Tzonkov; Olympia Roeva

    2006-01-01

    A set of three competing, unstructured models has been proposed to model biomass growth, glucose utilization, acetate formation, dissolved oxygen consumption and carbon dioxide accumulation of a fed-batch cultivation process of Escherichia coli. The inhibiting effect of acetate on growth of E. coli cultures is included in the considered models. The model identification is carried out using experimental data from the cultivation process. Genetic algorithms are used for parameter estimation. Th...

  12. Microarray long oligo probe designing for Escherichia coli: an in-silico DNA marker extraction

    Behzadi, Payam; Najafi, Ali; BEHZADI, Elham; Ranjbar, Reza

    2016-01-01

    Introduction Urinary tract infections are predominant diseases which may be caused by different pathogenic microorganisms, particularly Escherichia coli (E.coli). DNA microarray technology is an accurate, rapid, sensitive, and specific diagnostic tool which may lead to definite diagnosis and treatment of several infectious diseases. DNA microarray is a multi-process method in which probe designing plays an important. Therefore, the authors of the present study have tried to design a range of ...

  13. Polyphosphate Accumulation in Escherichia coli in Response to Defects in DNA Metabolism▿

    Amado, Luciana; Kuzminov, Andrei

    2009-01-01

    Phenol-chloroform extraction of [32P]orthophosphate-labeled Escherichia coli cells followed by alkaline gel electrophoresis revealed, besides the expected chromosomal DNA, two non-DNA species that we have identified as lipopolysaccharides and polyphosphates by using a combination of biochemical and genetic techniques. We used this serendipitously found straightforward protocol for direct polyphosphate detection to quantify polyphosphate levels in E. coli mutants with diverse defects in the DN...

  14. Detection and Classification of Live and Dead Escherichia coli by Laser-Induced Breakdown Spectroscopy

    P. Sivakumar; Fernández-Bravo, A.; Taleh, L.; J. F. Biddle; Melikechi, N.

    2015-01-01

    A common goal for astrobiology is to detect organic materials that may indicate the presence of life. However, organic materials alone may not be representative of currently living systems. Thus, it would be valuable to have a method with which to determine the health of living materials. Here, we present progress toward this goal by reporting on the application of laser-induced breakdown spectroscopy (LIBS) to study characteristics of live and dead cells using Escherichia coli (E. coli) stra...

  15. Inactivation of Enterohemorrhagic Escherichia coli in Rumen Content- or Feces-Contaminated Drinking Water for Cattle

    Zhao, Tong; Zhao, Ping; Joe W. West; Bernard, John K.; Cross, Heath G.; Doyle, Michael P.

    2006-01-01

    Cattle drinking water is a source of on-farm Escherichia coli O157:H7 transmission. The antimicrobial activities of disinfectants to control E. coli O157:H7 in on-farm drinking water are frequently neutralized by the presence of rumen content and manure that generally contaminate the drinking water. Different chemical treatments, including lactic acid, acidic calcium sulfate, chlorine, chlorine dioxide, hydrogen peroxide, caprylic acid, ozone, butyric acid, sodium benzoate, and competing E. c...

  16. Amino acid precursors for the detection of transketolase activity in Escherichia coli auxotrophs.

    Simon, Grégory; Bouzon, Madeleine; Charmantray, Franck; Hélaine, Virgil; Légeret, Bertrand; Marlière, Philippe; Hecquet, Laurence

    2009-07-15

    Probes were developed for the in vivo detection of transketolase activity by the use of a complementation assay in Escherichia coli auxotrophs They combine the d-threo ketose moiety recognised by transketolase and the side chain of leucine or methionine. These compounds were donor substrates of yeast transketolase leading to the release of the corresponding alpha-hydroxyaldehydes which could be converted in E. coli by a cascade of reactions into leucine or methionine required for cellular growth. PMID:19535247

  17. Optimal Cloning of PCR Fragments by Homologous Recombination in Escherichia coli

    Jacobus, Ana Paula; Gross, Jeferson

    2015-01-01

    PCR fragments and linear vectors containing overlapping ends are easily assembled into a propagative plasmid by homologous recombination in Escherichia coli. Although this gap-repair cloning approach is straightforward, its existence is virtually unknown to most molecular biologists. To popularize this method, we tested critical parameters influencing the efficiency of PCR fragments cloning into PCR-amplified vectors by homologous recombination in the widely used E. coli strain DH5α. We found...

  18. Analysis of cytokeratin domains by cloning and expression of intact and deleted polypeptides in Escherichia coli.

    Magin, T M; Hatzfeld, M; Franke, W W

    1987-01-01

    Using recombination of an appropriate expression vector system (pINDU) with a complete cDNA encoding a basic (type II) cytokeratin, i.e. cytokeratin 8 (1) of Xenopus laevis, we transformed Escherichia coli cells to synthesize considerable amounts of an insoluble eukaryotic cytoskeletal protein. The cytokeratin was deposited in large 'inclusion bodies' in the bacterial cytoplasm but did not form detectable filamentous structures. However, when the E. coli-expressed cytokeratin was purified and...

  19. Antimicrobial sensitivity pattern among clinical isolates of Escherichia coli in tertiary care centre of Northern India

    Ranjana Malhotra; Rama Sikka; Uma Chaudhary

    2016-01-01

    Background: Rampant rise in resistance to various antimicrobials among clinical isolates of Escherichia coli is an issue of serious concern, especially in developing countries. It not only causes failure in treatment but also pose a health burden over the society at large. Methods: Antimicrobial susceptibility testing was performed by Kirby-Bauer disc diffusion method on Muller Hinton agar as per Clinical and Laboratory Standard Institute recommendations over 100 isolates of E. coli. Isola...

  20. Alkaline gel electrophoresis assay to detect DNA strand breaks and repair mechanisms in Escherichia coli

    José Carlos Pelielo De Mattos; Ellen Serri da Motta; Márcia Betania Nunes de Oliveira; Flávio José da Silva Dantas; Adriano Caldeira de Araujo

    2008-01-01

    Reactive oxygen species (ROS) can induce lesions in different cellular targets, including DNA. Stannous chloride (SnCl2) is a ROS generator, leading to lethality in Escherichia coli (E. coli), with the base excision repair (BER) mechanism playing a role in this process. Many techniques have been developed to detect genotoxicity, as comet assay, in eukaryotic cells, and plasmid DNA agarose gel electrophoresis. In this study, an adaptation of the alkaline gel electrophoresis method was carried ...

  1. The role of heightened surveillance in an outbreak of Escherichia coli O157.H7.

    Roberts, C L; Mshar, P A; Cartter, M. L.; Hadler, J. L.; Sosin, D. M.; Hayes, P S; Barrett, T. J.

    1995-01-01

    After instituting laboratory screening for Escherichia coli O157.H7, a Connecticut hospital isolated the organism from four persons in September 1993. As a result, an outbreak of E. coli O157.H7 associated with a country club was detected. The club had served hamburger from the same shipment at two picnics. Attendees of two picnics were interviewed, stool cultures were obtained from symptomatic persons, and the remaining hamburger was cultured. Twenty (22%) of 89 persons who ate hamburger bec...

  2. Genome of Multidrug-Resistant Uropathogenic Escherichia coli Strain NA114 from India ▿

    Avasthi, Tiruvayipati Suma; Kumar, Narender; Baddam, Ramani; Hussain, Arif; Nandanwar, Nishant; Jadhav, Savita; Ahmed, Niyaz

    2011-01-01

    Uropathogenic Escherichia coli (UPEC) causes serious infections in people at risk and has a significant environmental prevalence due to contamination by human and animal excreta. In developing countries, UPEC assumes importance in certain dwellings because of poor community/personal hygiene and exposure to contaminated water or soil. We report the complete genome sequence of E. coli strain NA114 from India, a UPEC strain with a multidrug resistance phenotype and the capacity to produce extend...

  3. Epidemiological and clinical complexity of amoxicillin-clavulanate-resistant Escherichia coli.

    Rodríguez-Baño, Jesús; Oteo, Jesús; Ortega, Adriana; Villar, Macarena; Conejo, M Carmen; Bou, Germán; Aranzamendi-Zaldumbide, Maitane; Cercenado, Emilia; Gurguí, Mercè; Martínez-Martínez, Luis; Merino, María; Rivera, Alba; Oliver, Antonio; Weber, Irene; Pascual, Alvaro; Bartolomé, Rosa M; Gónzalez-López, Juan José; Campos, José

    2013-07-01

    Two hundred twelve patients with colonization/infection due to amoxicillin-clavulanate (AMC)-resistant Escherichia coli were studied. OXA-1- and inhibitor-resistant TEM (IRT)-producing strains were associated with urinary tract infections, while OXA-1 producers and chromosomal AmpC hyperproducers were associated with bacteremic infections. AMC resistance in E. coli is a complex phenomenon with heterogeneous clinical implications. PMID:23637303

  4. Characterization of Multiple-Antimicrobial-Resistant Escherichia coli Isolates from Diseased Chickens and Swine in China

    Yang, Hanchun; Chen, Sheng; White, David G.; Zhao, Shaohua; McDermott, Patrick; Walker, Robert; Meng, Jianghong

    2004-01-01

    Escherichia coli isolates from diseased piglets (n = 89) and chickens (n = 71) in China were characterized for O serogroups, virulence genes, antimicrobial susceptibility, class 1 integrons, and mechanisms of fluoroquinolone resistance. O78 was the most common serogroup identified (63%) among the chicken E. coli isolates. Most isolates were PCR positive for the increased serum survival gene (iss; 97%) and the temperature-sensitive hemagglutinin gene (tsh; 93%). The O serogroups of swine E. co...

  5. Prevention of clinical coliform mastitis in dairy cows by a mutant Escherichia coli vaccine.

    González, R N; Cullor, J S; Jasper, D. E.; Farver, T B; Bushnell, R B; Oliver, M N

    1989-01-01

    A prospective cohort study was undertaken in two commercial California dairies. The treatment group, 246 cows, received three doses of a whole cell bacterin of J5 Escherichia coli (mutant of E. coli O111:B4) plus Freund's incomplete adjuvant vaccine (two in the dry period and one after calving) while 240 unvaccinated cows served as controls. Thirty-five cases of clinical coliform mastitis were diagnosed, six in vaccinated cows and 29 in unvaccinated cows. Bacteria isolated from the clinical c...

  6. Metabolic Deficiences Revealed in the Biotechnologically Important Model Bacterium Escherichia coli BL21(DE3)

    Constanze Pinske; Markus Bönn; Sara Krüger; Ute Lindenstrauss; R Gary Sawers

    2011-01-01

    The Escherichia coli B strain BL21(DE3) has had a profound impact on biotechnology through its use in the production of recombinant proteins. Little is understood, however, regarding the physiology of this important E. coli strain. We show here that BL21(DE3) totally lacks activity of the four [NiFe]-hydrogenases, the three molybdenum- and selenium-containing formate dehydrogenases and molybdenum-dependent nitrate reductase. Nevertheless, all of the structural genes necessary for the synthesi...

  7. Effects of Simulated Mars Conditions on the Survival and Growth of Escherichia coli and Serratia liquefaciens▿

    Berry, Bonnie J.; Jenkins, David G.; Schuerger, Andrew C.

    2010-01-01

    Escherichia coli and Serratia liquefaciens, two bacterial spacecraft contaminants known to replicate under low atmospheric pressures of 2.5 kPa, were tested for growth and survival under simulated Mars conditions. Environmental stresses of high salinity, low temperature, and low pressure were screened alone and in combination for effects on bacterial survival and replication, and then cells were tested in Mars analog soils under simulated Mars conditions. Survival and replication of E. coli a...

  8. Advantage Provided by Iron for Escherichia coli Growth and Cultivability in Drinking Water

    Appenzeller, Brice M. R.; Yañez, Carolina; Jorand, Frederic; Block, Jean-Claude

    2005-01-01

    The presence of iron, used both as a nutrient and as an electron acceptor, was demonstrated to give an advantage to Escherichia coli bacteria in drinking water. Slight additions of ferrous sulfate to water with initial low iron concentrations led to a significant increase in the number of E. coli bacteria. The presence of ferric oxide in water under anaerobic conditions increased bacterial cultivability. PMID:16151163

  9. Comparison of antibiotic resistance patterns in collections of Escherichia coli and Proteus mirabilis uropathogenic strains

    Adamus-Bialek, Wioletta; Zajac, Elzbieta; Parniewski, Pawel; Kaca, Wieslaw

    2013-01-01

    Escherichia coli and Proteus mirabilis are important urinary tract pathogens. The constant increase in the antibiotic resistance of clinical bacterial strains has become an important clinical problem. The aim of this study was to compare the antibiotic resistance of 141 clinical (Sweden and Poland) and 42 laboratory (Czech Republic) P. mirabilis strains and 129 clinical (Poland) uropathogenic E. coli strains. The proportion of unique versus diverse patterns in Swedish clinical and laboratory ...

  10. Prevalence of Listeria monocytogenes, Salmonella spp. and Escherichia coli O157:H7 in Raw Milk

    ISSA, Ghassan; Tolga KAHRAMAN; KAHRAMAN, Beren

    2010-01-01

    ABSTRACTThe present study was undertaken to investigate the incidence of Listeria monocytogenes, Salmonella spp. and Escherichia coli O157:H7 in 350 composite milk samples (four quarters in one collection vial) obtained from five different farms in Istanbul. Each sample was aseptically taken straight from udder of individual cattle. The results showed that 0.57% (2/350) of milk samples were contaminated with L. monocytogenes. Salmonella spp. and E. coli O157:H7 were not detected in any sample...

  11. Escherichia coli extract-catalyzed recombination in switch regions of mouse immunoglobulin genes.

    Kataoka, T.; Takeda, S.; Honjo, T

    1983-01-01

    We have shown that Escherichia coli extracts catalyze recombination between mouse immunoglobulin mu and alpha genes inserted separately in lambda phage vectors carrying different genetic markers. Most of the recombination sites in the inserts are located in the switch regions of the heavy chain genes, as previously found in the expressed genes of myeloma cells. The recombination took place at relatively high frequency (10(-4)). The recombinational system in E. coli or lambda phage seems to pr...

  12. Antibacterial Activity of Some Plant Extracts Against Extended- Spectrum Beta-Lactamase Producing Escherichia coli Isolates

    Saeidi, Saeide; Amini Boroujeni, Negar; Ahmadi, Hassan; Hassanshahian, Mehdi

    2015-01-01

    Background: The extended-spectrum beta-lactamase (ESBL) -producing Escherichia coli isolates make many serious infections, especially urinary tract infections. Objectives: The purpose of this study was to determine the antibacterial activities of some natural plant extracts against ESBL-producing E. coli isolates, which harbor the TEM gene in urine samples of the patients who have urinary tract infections. Materials and Methods: Evaluation has to be exactly determined for both methods of disk...

  13. Antimicrobial Non-Susceptibility of Escherichia coli from Outpatients and Patients Visiting Emergency Rooms in Taiwan

    Wang, Jann-Tay; Chang, Shan-Chwen; Chang, Feng-Yee; Fung, Chang-Phone; Chuang, Yin-Ching; Chen, Yao-Shen; Shiau, Yih-Ru; Tan, Mei-Chen; Wang, Hui-Ying; Lai, Jui-Fen; Huang, I-Wen; Yang Lauderdale, Tsai-Ling

    2015-01-01

    Longitudinal nationwide surveillance data on antimicrobial non-susceptibility and prevalence of extended-spectrum β-lactamases (ESBLs) as well as AmpC β-lactamases producers among Escherichia coli from different sources in the community settings are limited. Such data may impact treatment practice. The present study investigated E. coli from outpatients and patients visiting emergency rooms collected by the Taiwan Surveillance of Antimicrobial Resistance (TSAR) program. A total of 3481 E. col...

  14. Expression of ovine gamma interferon in Escherichia coli and Corynebacterium glutamicum.

    Billman-Jacobe, H; Hodgson, A L; Lightowlers, M; Wood, P. R.; Radford, A J

    1994-01-01

    Bacteria of two species, Escherichia coli and Corynebacterium glutamicum, were used as hosts to express recombinant ovine gamma interferon as a fusion protein with glutathione S-transferase. The recombinant gamma interferon produced by both bacteria was biologically active in vitro and was recognized by anti-gamma interferon monoclonal antibodies. E. coli produced large amounts of soluble recombinant protein which could be purified by a simple affinity chromatography method. Only a small frac...

  15. The anaerobic ribonucleoside triphosphate reductase from Escherichia coli requires S-adenosylmethionine as a cofactor.

    Eliasson, R; Fontecave, M; Jörnvall, H; Krook, M; Pontis, E; Reichard, P

    1990-01-01

    Extracts from anaerobically grown Escherichia coli contain an oxygen-sensitive activity that reduces CTP to dCTP in the presence of NADPH, dithiothreitol, Mg2+ ions, and ATP, different from the aerobic ribonucleoside diphosphate reductase (2'-deoxyribonucleoside-diphosphate: oxidized-thioredoxin 2'-oxidoreductase, EC 1.17.4.1) present in aerobically grown E. coli. After fractionation, the activity required at least five components, two heat-labile protein fractions and several low molecular w...

  16. Foreshore Sand as a Source of Escherichia coli in Nearshore Water of a Lake Michigan Beach†

    Whitman, Richard L.; Nevers, Meredith B.

    2003-01-01

    Swimming advisories due to excessive Escherichia coli concentrations are common at 63rd Street Beach, Chicago, Ill. An intensive study was undertaken to characterize the source and fate of E. coli in beach water and sand at the beach. From April through September 2000, water and sand samples were collected daily or twice daily at two depths on three consecutive days per week (water samples, n = 1,747; sand samples, n = 858); hydrometeorological conditions and bird and bather distributions wer...

  17. Efficient Recovery of Fluoroquinolone-Susceptible and Fluoroquinolone-Resistant Escherichia coli Strains From Frozen Samples

    Lautenbach, Ebbing; Santana, Evelyn; Lee, Abby; Tolomeo, Pam; Black, Nicole; Babson, Andrew; Perencevich, Eli N.; Harris, Anthony D; Smith, Catherine A; Maslow, Joel

    2008-01-01

    We assessed the rate of recovery of fluoroquinolone-resistant and fluoroquinolone-susceptible Escherichia coli isolates from culture of frozen perirectal swab samples compared with the results for culture of the same specimen before freezing. Recovery rates for these 2 classes of E. coli were 91% and 83%, respectively. The majority of distinct strains recovered from the initial sample were also recovered from the frozen sample. The strains that were not recovered were typically present only i...

  18. Interaction of Escherichia coli K1 and K5 with Acanthamoeba castellanii Trophozoites and Cysts

    Matin, Abdul; Jung, Suk-Yul

    2011-01-01

    The existence of symbiotic relationships between Acanthamoeba and a variety of bacteria is well-documented. However, the ability of Acanthamoeba interacting with host bacterial pathogens has gained particular attention. Here, to understand the interactions of Escherichia coli K1 and E. coli K5 strains with Acanthamoeba castellanii trophozoites and cysts, association assay, invasion assay, survival assay, and the measurement of bacterial numbers from cysts were performed, and nonpathogenic E. ...

  19. In vitro inhibition of adhesion of Escherichia coli strains by Xylitol

    Annelisa Farah da Silva; Érika Yoko Suzuki; Aline Siqueira Ferreira; Murilo Gomes Oliveira; Sílvio Silvério da Silva; Nádia Rezende Barbosa Raposo

    2011-01-01

    The present study aimed to evaluate xylitol's antimicrobial and anti-adherence activities on Escherichia coli (ATCC 8739) and on another clinical strain enteropathogenic E. coli (EPEC). In vitro minimum inhibitory concentration (MIC) test and adhesion assays were performed using 0.5, 2.5 and 5.0% xylitol. It was found that xylitol did not have antimicrobial properties on these strains. The scanning electron microscopy (SEM) demonstrated that the slides treated with xylitol had a significant r...

  20. Antibiotic Selection of Escherichia coli Sequence Type 131 in a Mouse Intestinal Colonization Model

    Boetius Hertz, Frederik; Løbner-Olesen, Anders; Frimodt-Møller, Niels

    2014-01-01

    The ability of different antibiotics to select for extended-spectrum β-lactamase (ESBL)-producing Escherichia coli remains a topic of discussion. In a mouse intestinal colonization model, we evaluated the selective abilities of nine common antimicrobials (cefotaxime, cefuroxime, dicloxacillin, clindamycin, penicillin, ampicillin, meropenem, ciprofloxacin, and amdinocillin) against a CTX-M-15-producing E. coli sequence type 131 (ST131) isolate with a fluoroquinolone resistance phenotype. Mice ...