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Sample records for escherichia coli bacillus

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

    PubMed

    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

  2. IS231A from Bacillus thuringiensis is functional in Escherichia coli: transposition and insertion specificity.

    PubMed Central

    Hallet, B; Rezsöhazy, R; Delcour, J

    1991-01-01

    A kanamycin resistance gene was introduced within the insertion sequence IS231A from Bacillus thuringiensis, and transposition of the element was demonstrated in Escherichia coli. DNA sequencing at the target sites showed that IS231A transposition results in direct repeats of variable lengths (10, 11, and 12 bp). These target sequences resemble the terminal inverted repeats of the transposon Tn4430, which are the preferred natural insertion sites of IS231 in B. thuringiensis. Images PMID:1648561

  3. Cloning and expression in Escherichia coli of chromosomal mercury resistance genes from a Bacillus sp

    SciTech Connect

    Wang, Y.; Mahler, I.; Levinson, H.S.; Halvorson, H.O.

    1987-10-01

    A 7.9-kilobase (kb) chromosomal fragment was cloned from a mercury-resistant Bacillus sp. In Escherichia coli, in the presence of a second plasmid carrying functional transport genes, resistance to HgCl/sub 2/ and to phenylmercury acetate (PMA) was expressed. Shortening the cloned fragment to 3.8 kb abolished resistance to PMA but not to HgCl/sub 2/. In Bacillus subtilis, the 3.8-kb fragment produced mercuric reductase constitutively but did not produce resistance to HgCl/sub 2/ or to PMA.

  4. Autolysis of Escherichia coli and Bacillus subtilis cells in low gravity

    NASA Technical Reports Server (NTRS)

    Kacena, M. A.; Smith, E. E.; Todd, P.

    1999-01-01

    The role of gravity in the autolysis of Bacillus subtilis and Escherichia coli was studied by growing cells on Earth and in microgravity on Space Station Mir. Autolysis analysis was completed by examining the death phase or exponential decay of cells for approximately 4 months following the stationary phase. Consistent with published findings, the stationary-phase cell population was 170% and 90% higher in flight B. subtilis and E. coli cultures, respectively, than in ground cultures. Although both flight autolysis curves began at higher cell densities than control curves, the rate of autolysis in flight cultures was identical to that of their respective ground control rates.

  5. Hydraphiles enhance antimicrobial potency against Escherichia coli, Pseudomonas aeruginosa, and Bacillus subtilis.

    PubMed

    Patel, Mohit B; Garrad, Evan C; Stavri, Ariel; Gokel, Michael R; Negin, Saeedeh; Meisel, Joseph W; Cusumano, Zachary; Gokel, George W

    2016-06-15

    Hydraphiles are synthetic amphiphiles that form ion-conducting pores in liposomal membranes. These pores exhibit open-close behavior when studied by planar bilayer conductance techniques. In previous work, we showed that when co-administered with various antibiotics to the DH5α strain of Escherichia coli, they enhanced the drug's potency. We report here potency enhancements at low concentrations of hydraphiles for the structurally and mechanistically unrelated antibiotics erythromycin, kanamycin, rifampicin, and tetracycline against Gram negative E. coli (DH5α and K-12) and Pseudomonas aeruginosa, as well as Gram positive Bacillus subtilis. Earlier work suggested that potency increases correlated to ion transport function. The data presented here comport with the function of hydraphiles to enhance membrane permeability in addition to, or instead of, their known function as ion conductors. PMID:27166575

  6. Soluble Expression and Characterization of Biologically Active Bacillus anthracis Protective Antigen in Escherichia coli

    PubMed Central

    Suryanarayana, Nagendra; Vanlalhmuaka; Mankere, Bharti; Verma, Monika; Thavachelvam, Kulanthaivel; Tuteja, Urmil

    2016-01-01

    Bacillus anthracis secretory protein protective antigen (PA) is primary candidate for subunit vaccine against anthrax. Attempts to obtain large quantity of PA from Escherichia coli expression system often result in the formation of insoluble inclusion bodies. Therefore, it is always better to produce recombinant proteins in a soluble form. In the present study, we have obtained biologically active recombinant PA in small scale E. coli shake culture system using three different expression constructs. The PA gene was cloned in expression vectors bearing trc, T5, and T7 promoters and transformed into their respective E. coli hosts. The growth conditions were optimized to obtain maximum expression of PA in soluble form. The expression construct PA-pET32c in DE3-pLysS E. coli host resulted in a maximum production of soluble PA (15 mg L−1) compared to other combinations. Purified PA was subjected to trypsin digestion and binding assay with lethal factor to confirm the protein's functionality. Biological activity was confirmed by cytotoxicity assay on J774.1 cells. Balb/c mice were immunized with PA and the immunogenicity was tested by ELISA and toxin neutralization assay. This study highlights the expression of soluble and biologically active recombinant PA in larger quantity using simpler E. coli production platform. PMID:26966576

  7. Soluble Expression and Characterization of Biologically Active Bacillus anthracis Protective Antigen in Escherichia coli.

    PubMed

    Suryanarayana, Nagendra; Vanlalhmuaka; Mankere, Bharti; Verma, Monika; Thavachelvam, Kulanthaivel; Tuteja, Urmil

    2016-01-01

    Bacillus anthracis secretory protein protective antigen (PA) is primary candidate for subunit vaccine against anthrax. Attempts to obtain large quantity of PA from Escherichia coli expression system often result in the formation of insoluble inclusion bodies. Therefore, it is always better to produce recombinant proteins in a soluble form. In the present study, we have obtained biologically active recombinant PA in small scale E. coli shake culture system using three different expression constructs. The PA gene was cloned in expression vectors bearing trc, T5, and T7 promoters and transformed into their respective E. coli hosts. The growth conditions were optimized to obtain maximum expression of PA in soluble form. The expression construct PA-pET32c in DE3-pLysS E. coli host resulted in a maximum production of soluble PA (15 mg L(-1)) compared to other combinations. Purified PA was subjected to trypsin digestion and binding assay with lethal factor to confirm the protein's functionality. Biological activity was confirmed by cytotoxicity assay on J774.1 cells. Balb/c mice were immunized with PA and the immunogenicity was tested by ELISA and toxin neutralization assay. This study highlights the expression of soluble and biologically active recombinant PA in larger quantity using simpler E. coli production platform. PMID:26966576

  8. Environmental Dependence of Stationary-Phase Metabolism in Bacillus subtilis and Escherichia coli

    PubMed Central

    Chubukov, Victor

    2014-01-01

    When microbes lack the nutrients necessary for growth, they enter stationary phase. In cases when energy sources are still present in the environment, they must decide whether to continue to use their metabolic program to harvest the available energy. Here we characterized the metabolic response to a variety of types of nutrient starvation in Escherichia coli and Bacillus subtilis. We found that E. coli exhibits a range of phenotypes, with the lowest metabolic rates under nitrogen starvation and highest rates under magnesium starvation. In contrast, the phenotype of B. subtilis was dominated by its decision to form metabolically inactive endospores. While its metabolic rates under most conditions were thus lower than those of E. coli, when sporulation was suppressed by a genetic perturbation or an unnatural starvation condition, the situation was reversed. To further probe stationary-phase metabolism, we used quantitative metabolomics to investigate possible small-molecule signals that may regulate the metabolic rate of E. coli and initiate sporulation in B. subtilis. We hypothesize a role for phosphoenolpyruvate (PEP) in regulating E. coli glucose uptake and for the redox cofactors NAD(H) and NADP(H) in initiation of sporulation. Our work is directly relevant to synthetic biology and metabolic engineering, where active metabolism during stationary phase, which uncouples production from growth, remains an elusive goal. PMID:24584250

  9. Effect of berberine on Escherichia coli, Bacillus subtilis, and their mixtures as determined by isothermal microcalorimetry.

    PubMed

    Kong, Wei-Jun; Xing, Xiao-Yan; Xiao, Xiao-He; Zhao, Yan-Ling; Wei, Jian-He; Wang, Jia-Bo; Yang, Rui-Chuang; Yang, Mei-Hua

    2012-10-01

    The strong toxicity of pathogenic bacteria has resulted in high levels of morbidity and mortality in the general population. Developing effective antibacterial agents with high efficacy and long activity is in great demand. In this study, the microcalorimetric technique based on heat output of bacterial metabolism was applied to evaluate the effect of berberine on Escherichia coli, Bacillus subtilis, individually and in a mixture of both using a multi-channel microcalorimeter. The differences in shape of the power-time fingerprints and thermokinetic parameters of microorganism growth were compared. The results revealed that low concentration (20 μg/mL) of berberine began to inhibit the growth of E. coli and mixed microorganisms, while promoting the growth of B. subtilis; high concentration of berberine (over 100 μg/mL) inhibited B. subtilis. The endurance of E. coli to berberine was obviously lower than B. subtilis, and E. coli could decrease the endurance of B. subtilis to berberine. The sequence of half-inhibitory concentration (IC(50)) of berberine was: B. subtilis (952.37 μg/mL) > mixed microorganisms (682.47 μg/mL) > E. coli (581.69 μg/mL). Berberine might be a good selection of antibacterial agent used in the future. The microcalorimetric method should be strongly suggested in screening novel antibacterial agents for fighting against pathogenic bacteria. PMID:22878842

  10. Antibacterial Effects of Cissus welwitschii and Triumfetta welwitschii Extracts against Escherichia coli and Bacillus cereus

    PubMed Central

    2015-01-01

    Antibiotic resistance has increased sharply, while the pace for the development of new antimicrobials has slowed down. Plants provide an alternative source for new drugs. This study aimed to screen extracts from Cissus welwitschii and Triumfetta welwitschii for antibacterial activity against Escherichia coli and Bacillus cereus. The tests conducted included a susceptibility determination test, analysis of the effect of T. welwitschii on cell wall integrity, and transport across the membrane. It was found that the T. welwitschii methanol extracts were more effective than the water extracts and had the lowest minimum inhibitory concentration and minimum bactericidal concentration at 0.125 mg/mL and 0.5 mg/mL, respectively, against E. coli and B. cereus. The C. welwitschii extract caused the most drug accumulation in E. coli. In B. cereus, no significant drug accumulation was observed. Nucleic acid leakage in B. cereus and E. coli and protein leakage in E. coli were observed after exposure to the T. welwitschii extract. The extracts from T. welwitschii had greater antibacterial activity than the extracts from C. welwitschii. T. welwitschii may be a potential source of lead compounds for that could be developed into antibacterial agents. PMID:26904744

  11. Recipes for Antimicrobial Wine Marinades against Bacillus cereus, Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella enterica

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We evaluated bactericidal activities of several antimicrobial wine recipes consisting of red and white wine extracts of oregano leaves with added garlic juice and oregano oil against Bacillus cereus, Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella enterica. Dose-response plots were...

  12. Soluble expression of pullulanase from Bacillus acidopullulyticus in Escherichia coli by tightly controlling basal expression.

    PubMed

    Chen, Ana; Li, Yamei; Liu, Xiuxia; Long, Quan; Yang, Yankun; Bai, Zhonghu

    2014-12-01

    Bacillus acidopullulyticus pullulanase (BaPul13A) is a widely used debranching enzyme in the starch industry. A few details have been reported on the heterologous expression of BaPul13A in Escherichia coli (E. coli). This study compares different E. coli expression systems to improve the soluble expression level of BaPul13A. When pET22b(+)/pET28a(+) was used as the expression vector, the soluble expression of BaPul13A can be achieved by tightly controlling basal expression, whereas pET-20b(+)/pGEX4T2 leads to insoluble inclusion bodies. An efficient process control strategy aimed at minimizing the formation of inclusion bodies and enhancing the production of pullulanase was developed by a step decrease of the temperature in a 5-L fermentor. The highest total enzyme activity of BaPul13A reached 1,156.32 U/mL. This work reveals that the T7 promoter with lac operator and lacI gene collectively contribute to the soluble expression of BaPul13A, whereas either a T7 promoter alone or combined with the lac operator and lacI gene results in poor solubility. Basal expression in the initial growth phase of the host significantly affects the solubility of BaPul13A in E. coli. PMID:25312401

  13. Effects of Aronia melanocarpa constituents on biofilm formation of Escherichia coli and Bacillus cereus.

    PubMed

    Bräunlich, Marie; Økstad, Ole A; Slimestad, Rune; Wangensteen, Helle; Malterud, Karl E; Barsett, Hilde

    2013-01-01

    Many bacteria growing on surfaces form biofilms. Adaptive and genetic changes of the microorganisms in this structure make them resistant to antimicrobial agents. Biofilm-forming organisms on medical devices can pose serious threats to human health. Thus, there is a need for novel prevention and treatment strategies. This study aimed to evaluate the ability of Aronia melanocarpa extracts, subfractions and compounds to prevent biofilm formation and to inhibit bacterial growth of Escherichia coli and Bacillus cereus in vitro. It was found that several aronia substances possessed anti-biofilm activity, however, they were not toxic to the species screened. This non-toxic inhibition may confer a lower potential for resistance development compared to conventional antimicrobials. PMID:24317526

  14. Functional and Structural Characterization of Four Glutaminases from Escherichia coli and Bacillus subtilis†

    PubMed Central

    Brown, Greg; Singer, Alex; Proudfoot, Michael; Skarina, Tatiana; Kim, Youngchang; Chang, Changsoo; Dementieva, Irina; Kuznetsova, Ekaterina; Gonzalez, Claudio F.; Joachimiak, Andrzej; Savchenko, Alexei; Yakunin, Alexander F.

    2008-01-01

    Glutaminases belong to the large superfamily of serine-dependent β-lactamases and penicillin-binding proteins, and they catalyze the hydrolytic deamidation of l-glutamine to l-glutamate. In this work, we purified and biochemically characterized four predicted glutaminases from Escherichia coli (YbaS and YneH) and Bacillus subtilis (YlaM and YbgJ). The proteins demonstrated strict specificity to l-glutamine and did not hydrolyze d-glutamine or l-asparagine. In each organism, one glutaminase showed higher affinity to glutamine (E. coli YbaS and B. subtilis YlaM; Km 7.3 and 7.6 mM, respectively) than the second glutaminase (E. coli YneH and B. subtilis YbgJ; Km 27.6 and 30.6 mM, respectively). The crystal structures of the E. coli YbaS and the B. subtilis YbgJ revealed the presence of a classical β-lactamase-like fold and conservation of several key catalytic residues of β-lactamases (Ser74, Lys77, Asn126, Lys268, and Ser269 in YbgJ). Alanine replacement mutagenesis demonstrated that most of the conserved residues located in the putative glutaminase catalytic site are essential for activity. The crystal structure of the YbgJ complex with the glutaminase inhibitor 6-diazo-5-oxo-l-norleucine revealed the presence of a covalent bond between the inhibitor and the hydroxyl oxygen of Ser74, providing evidence that Ser74 is the primary catalytic nucleophile and that the glutaminase reaction proceeds through formation of an enzyme–glutamyl intermediate. Growth experiments with the E. coli glutaminase deletion strains revealed that YneH is involved in the assimilation of l-glutamine as a sole source of carbon and nitrogen and suggested that both glutaminases (YbaS and YneH) also contribute to acid resistance in E. coli. PMID:18459799

  15. Cloning of a fibrinolytic enzyme (subtilisin) gene from Bacillus subtilis in Escherichia coli.

    PubMed

    Ghasemi, Younes; Dabbagh, Fatemeh; Ghasemian, Abdollah

    2012-09-01

    Several investigations are being pursued to enhance the efficacy and specificity of fibrinolytic therapy. In this regard, microbial fibrinolytic enzymes attracted much more medical interests during these decades. Subtilisin, a member of subtilases (the superfamily of subtilisin-like serine proteases) and also a fibrinolytic enzyme is quite common in Gram-positive bacteria, and Bacillus species stand out in particular, as many extracellular and even intracellular variants have been identified. In the present work, the subtilisin gene from Bacillus subtilis PTCC 1023 was cloned into the vector pET-15b and expressed in Escherichia coli strain BL21 (DE3). Total genomic DNA were isolated and used for PCR amplification of the subtilisin gene by means of the specific primers. SDS-PAGE and enzyme assay were done for characterizing the expressed protein. A ~1,100 bp of the structural subtilisin gene was amplified. The DNA and amino acid sequence alignments resulting from the BLAST search of subtilisin showed high sequence identity with the other strains of B. subtilis, whereas significantly lower identity was observed with other bacterial subtilisins. The recombinant enzyme had the same molecular weight as other reported subtilisins and the E. coli transformants showed high subtilisin activity. This study provides evidence that subtilisin can be actively expressed in E. coli. The commercial availability of subtilisin is of great importance for industrial applications and also pharmaceutical purposes as thrombolytic agent. Thus, the characterization of new recombinant subtilisin and the development of rapid, simple, and effective production methods are not only of academic interest, but also of practical importance. PMID:22069026

  16. Recombinant expression and characterization of a novel endoglucanase from Bacillus subtilis in Escherichia coli.

    PubMed

    Zafar, Muddassar; Ahmed, Sibtain; Khan, Muhammad Imran Mahmood; Jamil, Amer

    2014-05-01

    The goal of this work was to produce high levels of endoglucanase in Escherichia coli for its potential usage in different industrial applications. Endoglucanase gene was amplified from genomic DNA of Bacillus subtilis JS2004 by PCR. The isolated putative endoglucanase gene consisted of an open reading frame of 1,701 nucleotides and encoded a protein of 567 amino acids with a molecular mass of 63-kDa. The gene was cloned into pET-28a(+) and expressed in E. coli BL21 (DE3). Optimum temperature and pH of the recombinant endoglucanase were 50 °C and 9, respectively which makes it very attractive for using in bio-bleaching and pulp industry. It had a K M of 1.76 μmol and V max 0.20 μmol/min with carboxymethylcellulose as substrate. The activity of recombinant endoglucanse was enhanced by Mg2+, Ca2+, isopropanol and Tween 20 and inhibited by Hg2+, Zn2+, Cu2+, Ni2+ and SDS. The activity of this recombinant endoglucanase was significantly higher than wild type. Therefore, this recombinant enzyme has potential for many industrial applications involving biomass conversions, due to characteristic of broad pH and higher temperature stability. PMID:24493451

  17. Novel broad host range shuttle vectors for expression in Escherichia coli, Bacillus subtilis and Pseudomonas putida.

    PubMed

    Troeschel, Sonja Christina; Thies, Stephan; Link, Olga; Real, Catherine Isabell; Knops, Katja; Wilhelm, Susanne; Rosenau, Frank; Jaeger, Karl-Erich

    2012-10-15

    Novel shuttle vectors named pEBP were constructed to allow the gene expression in different bacterial hosts including Escherichia coli, Bacillus subtilis and Pseudomonas putida. These vectors share the inducible promoters P(T7) and P(Xyl) and a cos site to enable packaging of plasmid DNA into phage, and carry different multiple cloning sites and antibiotic resistance genes. Vector pEBP41 generally replicates episomally while pEBP18 replicates episomally in Gram-negative bacteria only, but integrates into the chromosome of B. subtilis. Plasmid copy numbers determined for E. coli and P. putida were in the range of 5-50 per cell. The functionality of pEBP18 and pEBP41 was confirmed by expression of two lipolytic enzymes, namely lipase A from B. subtilis and cutinase from the eukaryotic fungus Fusarium solani pisi in three different host strains. Additionally, we report here the construction of a T7 RNA polymerase-based expression strain of P. putida. PMID:22440389

  18. Heterologous expression and secretion of an antifungal Bacillus subtilis chitosanase (CSNV26) in Escherichia coli.

    PubMed

    Kilani-Feki, Olfa; Frikha, Fakher; Zouari, Imen; Jaoua, Samir

    2013-07-01

    The aims of the study were the production improvement, the purification, the characterization and the activity investigation of chitosanase CSNV26 of Bacillus subtilis (V26). The gene csnV26 encoding for this protein was amplified and cloned in the pBAD vector then expressed in Escherichia coli (Top10). The SDS-PAGE and zymogram analysis of the recombinant protein showed that it has two active forms sized 27 and 31 kDa, corresponding to the protein with and without signal peptide. This protein has the particularity of being secreted by Top10-pBAD-csnV26 with a high yield of 6.2 g/l. The HPLC purification of CSNV26 from supernatant confirmed the presence of the two sizes. The investigation of the CSNV26 thermostability showed that the pure protein is highly stable keeping 68 % of its activity after 30-min treatment at 100 °C, contrarily to the protein present within the supernatant of E. coli and B. subtilis (V26). The molecular dynamics study of the predicted structure of protein in both forms showed that the presence of the peptide signal in the form of 31 kDa gave it a remarkable thermal stability. The antifungal activity of CSNV26 was evidenced on Rhizopus nigricans and Rhizopus oryzae. Indeed, it has provoked an alteration and embrittlement of their hyphae with onset of protoplast. PMID:23065029

  19. Hydride transfer catalysed by Escherichia coli and Bacillus subtilis dihydrofolate reductase: coupled motions and distal mutations.

    PubMed

    Hammes-Schiffer, Sharon; Watney, James B

    2006-08-29

    This paper reviews the results from hybrid quantum/classical molecular dynamics simulations of the hydride transfer reaction catalysed by wild-type (WT) and mutant Escherichia coli and WT Bacillus subtilis dihydrofolate reductase (DHFR). Nuclear quantum effects such as zero point energy and hydrogen tunnelling are significant in these reactions and substantially decrease the free energy barrier. The donor-acceptor distance decreases to ca 2.7 A at transition-state configurations to enable the hydride transfer. A network of coupled motions representing conformational changes along the collective reaction coordinate facilitates the hydride transfer reaction by decreasing the donor-acceptor distance and providing a favourable geometric and electrostatic environment. Recent single-molecule experiments confirm that at least some of these thermally averaged equilibrium conformational changes occur on the millisecond time-scale of the hydride transfer. Distal mutations can lead to non-local structural changes and significantly impact the probability of sampling configurations conducive to the hydride transfer, thereby altering the free-energy barrier and the rate of hydride transfer. E. coli and B. subtilis DHFR enzymes, which have similar tertiary structures and hydride transfer rates with 44% sequence identity, exhibit both similarities and differences in the equilibrium motions and conformational changes correlated to hydride transfer, suggesting a balance of conservation and flexibility across species. PMID:16873124

  20. In vitro transcription of the Bacillus subtilis phage phi 29 DNA by Bacillus subtilis and Escherichia coli RNA polymerases.

    PubMed Central

    Sogo, J M; Lozano, M; Salas, M

    1984-01-01

    The Escherichia coli RNA polymerase bound to phage phi 29 DNA has been visualized by electron microscopy. Thirteen specific binding sites have been observed at 1.7,2.6,5.5,10.4,13.7,25.2,25.7,26.3,33.5,59.5,69.2,91.7 and 99.6 DNA length units and they have been named A1,A1I,A1II,A1III,A1IV,A2,A2I, A3, A4,B1,B1I,C1 and C2, respectively. The binding sites A1,A2,A3,B1,C1 and C2 coincide with those found with Bacillus subtilis RNA polymerase. The transcription of phage phi 29 DNA with B. subtilis or E. coli RNA polymerases has been studied. With the B. subtilis RNA polymerase eight transcripts were found, starting at positions corresponding to the binding sites A1, A1III, A2,A3,B1I,B2,C1 and C2, respectively. With the E. coli RNA polymerase the same transcripts were found and a new one starting at position corresponding to the A4 binding site. The RNAs starting at binding sites A1,A1III,A2,B1I, B2,C1 and C2 are transcribed from right to left, as expected for early RNA. The RNAs which initiate at positions A3 and A4 are transcribed from left to right and probably correspond to late RNAs. Images PMID:6322128

  1. Escherichia Coli

    ERIC Educational Resources Information Center

    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…

  2. Inactivation efficiency to Bacillus subtilis and Escherichia coli bacterial aerosols of spraying neutral electrolyzed water.

    PubMed

    Chuang, Chi-Yu; Yang, Shinhao; Chang, Ming-Yih; Huang, Hsiao-Chien; Luo, Chin-Hsiang; Hung, Po-Chen; Fang, Wei

    2013-12-01

    The main objective of this study is to apply neutral electrolyzed water (NEW) spraying to inactivate bioaerosols. We evaluated the inactivation efficiency of NEW applied to inactivate two airborne bacterial Escherichia coli and Bacillus subtilis aerosols inside an environmental-controlled chamber in the study. Generated with electrolyzing 6.15 M sodium chloride brine, the NEW with free available chlorine (FAC) concentration 50, 100, and 200 ppm was pumped with an air pressure of 70 kg/cm2 through nozzle into the chamber to inactive E. coli and B. subtilis aerosols precontaminated air (initial counts of 3 x 10(4) colony-forming units [CFU]/m3). Bacterial aerosols were collected and cultured from chamber before and after NEW spray. The air exchange rate (ACH, hr(-1)) of the chamber was set to simulate fresh air ventilating dilution of indoor environment. First-order concentration decaying coefficients (Ka, min(-1)) of both bacterial aerosols were measured as an index of NEW inactivation efficiency. The result shows that higher FAC concentration of NEW spray caused better inactivation efficiency. The Ka values under ACH 1.0 hr(-1) were 0.537 and 0.598 for E. coli of FAC 50 and 100 ppm spraying, respectively. The Ka values of FAC 100 ppm and 200 ppm spraying for B. subtilis were 0.063 and 0.085 under ACH 1.0 hr(-1), respectively. The results indicated that NEW spray is likely to be effective in inactivation of bacterial airborne contamination. Moreover, it is observed in the study that the increase of ventilation rate and the use of a larger orifice-size nozzle may facilitate the inactivation efficiency. PMID:24558707

  3. Function of Corynebacterium glutamicum promoters in Escherichia coli, Streptomyces lividans, and Bacillus subtilis.

    PubMed

    Pátek, Miroslav; Muth, Günther; Wohlleben, Wolfgang

    2003-09-01

    The function of seven promoters from Corynebacterium glutamicum, P-hom, P-leuA, P-per, P-aes1, P-aes2, P-45, and P-104, was analyzed in a heterologous background. DNA fragments carrying the promoters were cloned into shuttle promoter-probe vectors replicating in Escherichia coli and C. glutamicum (pET2), Streptomyces lividans (pGL7011) and Bacillus subtilis (pRB394). With the exception of P-hom, P-leuA and P-104 in B. subtilis, all promoters were found to be active in all species. Non-radioactive methods of primer-extension analysis and of S1-nuclease protection assay using automatic sequencer were developed to determine the respective transcriptional start points (TSPs). All TSPs were determined by primer extension and in two promoters (P-45 and P-hom) the main TSPs were confirmed by S1-mapping. While the main TSPs were identical in all four species, utilization of multiple TSPs varied among the species and additional TSPs were detected in S. lividans. Knowledge of the efficiency of promoters and of exact respective TSPs may be of practical value for the construction of expression systems in a heterologous background. PMID:12948649

  4. Purification and characterization of the Bacillus subtilis levanase produced in Escherichia coli.

    PubMed Central

    Wanker, E; Huber, A; Schwab, H

    1995-01-01

    The enzyme levanase encoded by the sacC gene from Bacillus subtilis was overexpressed in Escherichia coli with the strong, inducible tac promoter. The enzyme was purified from crude E. coli cell lysates by salting out with ammonium sulfate and chromatography on DEAE-Sepharose CL-6B, S-Sepharose, and MonoQ-Sepharose. The purified protein had an apparent molecular mass of 75,000 Da in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, which is in agreement with that expected from the nucleotide sequence. Levanase was active on levan, inulin, and sucrose with Km values of 1.2 microM, 6.8 mM, and 65 mM, respectively. The pH optimum of the enzyme acting on inulin was 5.5, and the temperature optimum was 55 degrees C. Levanase was rapidly inactivated at 60 degrees C, but activity could be retained for longer times by adding fructose or glycerol. The enzyme activity was completely inactivated by Ag+ and Hg2+ ions, indicating that a sulfhydryl group is involved. A ratio of sucrase to inulinase activity of 1.2 was found for the purified enzyme with substrate concentrations of 50 mg/ml. The mechanism of enzyme action was investigated. No liberation of fructo-oligomers from inulin and levan could be observed by thin-layer chromatography and size exclusion chromatography-low-angle laser light scattering-interferometric differential refractive index techniques. This indicates that levanase is an exoenzyme acting by the single-chain mode. PMID:7646030

  5. Purification and characterization of a Bacillus polymyxa beta-glucosidase expressed in Escherichia coli.

    PubMed Central

    Painbeni, E; Valles, S; Polaina, J; Flors, A

    1992-01-01

    The beta-glucosidase encoded by the bglA gene from Bacillus polymyxa was overproduced in Escherichia coli by using a plasmid in which bglA is under control of the lacI promoter. Induction with isopropyl-beta-D-thiogalactopyranoside allowed an increase in the specific activity of the enzyme of about 100 times the basal level of gene expression. The enzyme was purified by a two-step procedure involving salting out with ammonium sulfate and ion-exchange chromatography with DEAE-cellulose. Fractions of beta-glucosidase activity recovered by this procedure, after electrophoresis in an acrylamide gel and staining with silver nitrate, yielded a single band of protein. This band was shown by a zymogram to correspond to beta-glucosidase activity. The purified protein showed an apparent molecular mass of 50 kDa and an isoelectric point of 4.6, values in agreement with those expected from the nucleotide sequence of the gene. Km values of the enzyme, with either cellobiose or p-nitrophenyl-beta-D-glucoside as the substrate, were determined. It was shown that the enzyme is competitively inhibited by glucose. The effects of different metallic ions and other agents were studied. Hg2+ was strongly inhibitory, while none of the other cations tested had any significant effect. Ethanol did not show the stimulating effect observed with other beta-glucosidases. The mechanism of enzyme action was investigated. High-pressure liquid chromatography analysis with cellobiose as the substrate confirmed previous data revealing the formation of two products, glucose and another, unidentified, compound. Results presented here indicate that this compound is cellotriose formed by transglycosylation. Images PMID:1569036

  6. Improvement of culture conditions to overproduce beta-galactosidase from Escherichia coli in Bacillus subtilis.

    PubMed

    Martínez, A; Ramírez, O T; Valle, F

    1997-01-01

    The effect of some culture variables in the production of beta-galactosidase from Escherichia coli in Bacillus subtilis was evaluated. The lacZ gene was expressed in B. subtilis using the regulatory region of the subtilisin gene aprE. The host contained also the hpr2 and degU32 mutations, which are known to overexpress the aprE gene. We found that, when this overproducing B. subtilis strain was grown in mineral medium supplemented with glucose (MMG), beta-galactosidase production was partially growth-associated, as 40%-60% of the maximum enzyme activity was produced before the onset of the stationary phase. In contrast, when a complex medium was used, beta-galactosidase was produced only at low levels during vegetative growth, whereas it accumulated to high levels during early stationary phase. Compared with the results obtained in complex media, a 20% increase in specific beta-galactosidase activity in MMG supplemented with 11.6 g/l glucose was obtained. On the 1-1 fermenter scale, a three-fold increase in volumetric beta-galactosidase activity was obtained when the glucose concentration was varied from 11 g/l to 26 g/l. In addition, glucose feeding during the stationary phase resulted in a twofold increase in volumetric enzyme activity as cellular lysis was prevented. Finally, we showed that oxygen uptake and carbon dioxide evolution rates can be used for on-line determination of the onset of stationary phase, glucose depletion and biomass concentration. PMID:9035409

  7. Production and purification of Bacillus anthracis protective antigen from Escherichia coli.

    PubMed

    Laird, Michael W; Zukauskas, David; Johnson, Kelly; Sampey, Gavin C; Olsen, Henrik; Garcia, Andy; Karwoski, Jeffrey D; Cooksey, Bridget A; Choi, Gil H; Askins, Janine; Tsai, Amos; Pierre, Jennifer; Gwinn, William

    2004-11-01

    Anthrax is caused by the gram-positive, spore-forming bacterium, Bacillus anthracis. The anthrax toxin consists of three proteins, protective antigen (PA), lethal factor, and edema factor. Current vaccines against anthrax use PA as their primary component since it confers protective immunity. In this work, we expressed soluble, recombinant PA in relatively high amounts in the periplasm of E. coli from shake flasks and bioreactors. The PA protein was purified using Q-Sepharose-HP and hydroxyapatite chromatography, and routinely found to be 96-98% pure. Yields of purified PA varied depending on the method of production; however, medium cell density fermentations resulted in approximately 370 mg/L of highly pure biologically active PA protein. These results exhibit the ability to generate gram quantities of PA from E. coli. PMID:15477093

  8. PHYSICOCHEMICAL INTERACTION OF ESCHERICHIA COLI CELL ENVELOPES AND BACILLUS SUBTILIS CELL WALLS WITH TWO CLAYS AND ABILITY OF THE COMPOSITE TO IMMOBILIZE HEAVY METALS FROM SOLUTION

    EPA Science Inventory

    Isolated Escherichia coli K-l2 cell envelopes or Bacillus subtilis 168 cell walls were reacted with smectite or kaolinite clay in distilled deionized water (pH 6.0); unbound envelopes or walls were separated by sucrose density gradient centrifugation, and the extent of adsorption...

  9. Cloning and nucleotide sequencing of a novel 7 beta-(4-carboxybutanamido)cephalosporanic acid acylase gene of Bacillus laterosporus and its expression in Escherichia coli and Bacillus subtilis.

    PubMed

    Aramori, I; Fukagawa, M; Tsumura, M; Iwami, M; Ono, H; Kojo, H; Kohsaka, M; Ueda, Y; Imanaka, H

    1991-12-01

    A strain of Bacillus species which produced an enzyme named glutaryl 7-ACA acylase which converts 7 beta-(4-carboxybutanamido)cephalosporanic acid (glutaryl 7-ACA) to 7-amino cephalosporanic acid (7-ACA) was isolated from soil. The gene for the glutaryl 7-ACA acylase was cloned with pHSG298 in Escherichia coli JM109, and the nucleotide sequence was determined by the M13 dideoxy chain termination method. The DNA sequence revealed only one large open reading frame composed of 1,902 bp corresponding to 634 amino acid residues. The deduced amino acid sequence contained a potential signal sequence in its amino-terminal region. Expression of the gene for glutaryl 7-ACA acylase was performed in both E. coli and Bacillus subtilis. The enzyme preparations purified from either recombinant strain of E. coli or B. subtilis were shown to be identical with each other as regards the profile of sodium dodecyl sulfate-polyacrylamide gel electrophoresis and were composed of a single peptide with the molecular size of 70 kDa. Determination of the amino-terminal sequence of the two enzyme preparations revealed that both amino-terminal sequences (the first nine amino acids) were identical and completely coincided with residues 28 to 36 of the open reading frame. Extracellular excretion of the enzyme was observed in a recombinant strain of B. subtilis. PMID:1744041

  10. Bacillus subtilis and Escherichia coli essential genes and minimal cell factories after one decade of genome engineering.

    PubMed

    Juhas, Mario; Reuß, Daniel R; Zhu, Bingyao; Commichau, Fabian M

    2014-11-01

    Investigation of essential genes, besides contributing to understanding the fundamental principles of life, has numerous practical applications. Essential genes can be exploited as building blocks of a tightly controlled cell 'chassis'. Bacillus subtilis and Escherichia coli K-12 are both well-characterized model bacteria used as hosts for a plethora of biotechnological applications. Determination of the essential genes that constitute the B. subtilis and E. coli minimal genomes is therefore of the highest importance. Recent advances have led to the modification of the original B. subtilis and E. coli essential gene sets identified 10 years ago. Furthermore, significant progress has been made in the area of genome minimization of both model bacteria. This review provides an update, with particular emphasis on the current essential gene sets and their comparison with the original gene sets identified 10 years ago. Special attention is focused on the genome reduction analyses in B. subtilis and E. coli and the construction of minimal cell factories for industrial applications. PMID:25092907

  11. Synthetic operon for (R,R)-2,3-butanediol production in Bacillus subtilis and Escherichia coli.

    PubMed

    de Oliveira, Rafael R; Nicholson, Wayne L

    2016-01-01

    To reduce dependence on petroleum, an alternative route to production of the chemical feedstock 2,3-butanediol (2,3-BD) from renewable lignocellulosic sources is desirable. In this communication, the genes encoding the pathway from pyruvate to 2,3-BD (alsS, alsD, and bdhA encoding acetolactate synthase, acetolactate decarboxylase, and butanediol dehydrogenase, respectively) from Bacillus subtilis were engineered into a single tricistronic operon under control of the isopropyl β-D-1-thiogalactopyranoside (IPTG)-inducible Pspac promoter in a shuttle plasmid capable of replication and expression in either B. subtilis or Escherichia coli. We describe the construction and performance of a shuttle plasmid carrying the IPTG-inducible synthetic operon alsSDbdhA coding for 2,3-BD pathway capable of (i) expression in two important representative model microorganisms, the gram-positive B. subtilis and the gram-negative E. coli; (ii) increasing 2,3-BD production in B. subtilis; and (iii) successfully introducing the B. subtilis 2,3-BD pathway into E. coli. The synthetic alsSDbdhA operon constructed using B. subtilis native genes not only increased the 2,3-BD production in its native host but also efficiently expressed the pathway in the heterologous organism E. coli. Construction of an efficient shuttle plasmid will allow investigation of 2,3-BD production performance in related organisms with industrial potential for production of bio-based chemicals. PMID:26454865

  12. Cloning and sequencing of the metallothioprotein beta-lactamase II gene of Bacillus cereus 569/H in Escherichia coli.

    PubMed Central

    Hussain, M; Carlino, A; Madonna, M J; Lampen, J O

    1985-01-01

    The structural gene for beta-lactamase II (EC 3.5.2.6), a metallothioenzyme, from Bacillus cereus 569/H (constitutive for high production of the enzyme) was cloned in Escherichia coli, and the nucleotide sequence was determined. This is the first class B beta-lactamase whose primary structure has been reported. The amino acid sequence of the exoenzyme form, deduced from the DNA, indicates that beta-lactamase II, like other secreted proteins, is synthesized as a precursor with a 30-amino acid N-terminal signal peptide. The pre-beta-lactamase II (Mr, 28,060) is processed in E. coli and in B. cereus to a single mature protein (Mr, 24,932) which is totally secreted by B. cereus but in E. coli remains intracellular, probably in the periplasm. The expression of the gene in E. coli RR1 on the multicopy plasmid pRWHO12 was comparable to that in B. cereus, where it is presumably present as a single copy. The three histidine residues that are involved (along with the sole cysteine of the mature protein) in Zn(II) binding and hence in enzymatic activity against beta-lactams were identified. These findings will help to define the secondary structure, mechanism of action, and evolutionary lineage of B. cereus beta-lactamase II and other class B beta-lactamases. Images PMID:3930467

  13. High-level expression of Bacillus naganoensis pullulanase from recombinant Escherichia coli with auto-induction: effect of lac operator.

    PubMed

    Nie, Yao; Yan, Wei; Xu, Yan; Chen, Wen Bo; Mu, Xiao Qing; Wang, Xinye; Xiao, Rong

    2013-01-01

    Pullulanase plays an important role in specific hydrolysis of branch points in amylopectin and is generally employed as an important enzyme in starch-processing industry. So far, however, the production level of pullulanase is still somewhat low from wide-type strains and even heterologous expression systems. Here the gene encoding Bacillus naganoensis pullulanase was amplified and cloned. For expression of the protein, two recombinant systems, Escherichia coli BL21(DE3)/pET-20b(+)-pul and E. coli BL21(DE3)/pET-22b(+)-pul, were constructed, both bearing T7 promoter and signal peptide sequence, but different in the existance of lac operator and lacI gene encoding lac repressor. Recombinant pullulanase was initially expressed with the activity of up to 14 U/mL by E. coli BL21(DE3)/pET-20b(+)-pul with IPTG induction in LB medium, but its expression level reduced continually with the extension of cryopreservation time and basal expression was observed. However, E. coli BL21(DE3)/pET-22b(+)-pul , involving lac operator downstream of T7 promoter to regulate foreign gene transcription, exhibited pullulanase activity consistently without detected basal expression. By investigating the effect of lac operator, basal expression of foreign protein was found to cause expression instability and negative effect on production of target protein. Thus double-repression strategy was proposed that lac operators in both chromosome and plasmid were bound with lac repressor to repress T7 RNA polymerase synthesis and target protein expression before induction. Consequently, the total activity of pullulanase was remarkably increased to 580 U/mL with auto-induction by lac operator-involved E. coli BL21(DE3)/pET-22b(+)-pul. When adding 0.6% glycine in culture, the extracellular production of pullulanase was significantly improved with the extracellular activity of 502 U/mL, which is a relatively higher level achieved to date for extracellular production of pullulanase. The successful

  14. High-Level Expression of Bacillus naganoensis Pullulanase from Recombinant Escherichia coli with Auto-Induction: Effect of lac Operator

    PubMed Central

    Xu, Yan; Chen, Wen Bo; Mu, Xiao Qing; Wang, Xinye; Xiao, Rong

    2013-01-01

    Pullulanase plays an important role in specific hydrolysis of branch points in amylopectin and is generally employed as an important enzyme in starch-processing industry. So far, however, the production level of pullulanase is still somewhat low from wide-type strains and even heterologous expression systems. Here the gene encoding Bacillus naganoensis pullulanase was amplified and cloned. For expression of the protein, two recombinant systems, Escherichia coli BL21(DE3)/pET-20b(+)-pul and E. coli BL21(DE3)/pET-22b(+)-pul, were constructed, both bearing T7 promoter and signal peptide sequence, but different in the existance of lac operator and lacI gene encoding lac repressor. Recombinant pullulanase was initially expressed with the activity of up to 14 U/mL by E. coli BL21(DE3)/pET-20b(+)-pul with IPTG induction in LB medium, but its expression level reduced continually with the extension of cryopreservation time and basal expression was observed. However, E. coli BL21(DE3)/pET-22b(+)-pul , involving lac operator downstream of T7 promoter to regulate foreign gene transcription, exhibited pullulanase activity consistently without detected basal expression. By investigating the effect of lac operator, basal expression of foreign protein was found to cause expression instability and negative effect on production of target protein. Thus double-repression strategy was proposed that lac operators in both chromosome and plasmid were bound with lac repressor to repress T7 RNA polymerase synthesis and target protein expression before induction. Consequently, the total activity of pullulanase was remarkably increased to 580 U/mL with auto-induction by lac operator-involved E. coli BL21(DE3)/pET-22b(+)-pul. When adding 0.6% glycine in culture, the extracellular production of pullulanase was significantly improved with the extracellular activity of 502 U/mL, which is a relatively higher level achieved to date for extracellular production of pullulanase. The successful

  15. Efficient constitutive expression of Bacillus subtilis xylanase A in Escherichia coli DH5alpha under the control of the Bacillus BsXA promoter.

    PubMed

    Ruller, Roberto; Rosa, José César; Faça, Victor M; Greene, Lewis J; Ward, Richard J

    2006-01-01

    Xylanase A (XynA) is a class G/11 xylanase secreted by Bacillus subtilis. XynA was purified to homogeneity from B. subtilis strain 168 culture supernatants by ethanol precipitation and cation-exchange chromatography. The DNA fragment encoding the XynA together with the BsXA promoter region was amplified by PCR from B. subtilis 168 genomic DNA, and cloned into the plasmid pT7T3 to give the plasmid pT7BsXA. After transformation of Escherichia coli DH5alpha with pT7BsXA, a 19-fold increase in the levels of the secreted XynA was detected in the supernatant as compared with the B. subtilis culture. Correct post-translation modification of the recombinant protein was confirmed by N-terminal amino acid sequencing and MS analyses. The pH- and temperature-dependences of the native and recombinant proteins were identical, indicating that the pT7BsXA may be useful for the constitutive expression of heterologous protein in E. coli. PMID:15982188

  16. Mutation and killing of Escherichia coli expressing a cloned Bacillus subtilis gene whose product alters DNA conformation.

    PubMed Central

    Setlow, J K; Randesi, M; Adams, J G; Setlow, B; Setlow, P

    1992-01-01

    Expression of the Bacillus subtilis gene coding for SspC, a small, acid-soluble protein, caused both killing and mutation in a number of Escherichia coli B and K-12 strains. SspC was previously shown to bind E. coli DNA in vivo, and in vitro this protein binds DNA and converts it into an A-like conformation. Analysis of revertants of nonsense mutations showed that SspC caused single-base changes, and a greater proportion of these were at A-T base pairs. Mutation in the recA gene abolished the induction of mutations upon synthesis of SspC, but the killing was only slightly greater than in RecA+ cells. Mutations in the umuC and umuD genes eliminated most of the mutagenic effect of SspC but not the killing, while the lexA mutation increased mutagenesis but did not appreciably affect the killing. Since there was neither killing nor mutation of E. coli after synthesis of a mutant SspC which does not bind DNA, it appears likely that the binding of wild-type SspC to DNA, with the attendant conformational change, was responsible for the killing and mutation. A strain containing the B. subtilis gene that is constitutive for the RecA protein at 42 degrees C showed a lower frequency of mutation when that temperature was used to induce the RecA protein than when the temperature was 30 degrees C, where the RecA level is low, suggesting that at the elevated temperature the high RecA level could be inhibiting binding of the B. subtilis protein to DNA. PMID:1314805

  17. Escherichia coli (E. coli)

    MedlinePlus

    ... so you might hear about E. coli being found in drinking water, which are not themselves harmful, but indicate the ... at CDC Foodborne disease Travelers' Health: Safe Food & Water Healthy Swimming E. coli Infection & Farm ... Word file Microsoft Excel file Audio/Video file Apple ...

  18. Enhanced extracellular production of recombinant Bacillus deramificans pullulanase in Escherichia coli through induction mode optimization and a glycine feeding strategy.

    PubMed

    Zou, Chun; Duan, Xuguo; Wu, Jing

    2014-11-01

    Process optimization strategies were developed to improve extracellular production of recombinant Bacillus deramificans pullulanase in Escherichia coli. Cell growth and pullulanase production in shake-flask cultures were investigated as a function of the concentration of added glycine, and the type and concentration of inducer. From the results of these experiments, a fed-batch fermentation strategy for high-cell-density cultivation was applied in a 3-L fermentor. The gradual addition of lactose was utilized for the induction of protein expression. The optimal lactose feeding rate and induction point were 0.4gL(-1)h(-1) and a dry cell weight (DCW) of 15gL(-1), respectively. Furthermore, a glycine feeding strategy was formulated to promote the secretion of recombinant protein. The optimal total and extracellular pullulanase activity were 2523.5 and 1567.9UmL(-1), respectively, which represent 1.2 and 22.6-fold increases compared with those observed under unoptimized conditions. PMID:25261864

  19. Cloning, sequencing, and expression of thermophilic Bacillus sp. strain TB-90 urease gene complex in Escherichia coli.

    PubMed

    Maeda, M; Hidaka, M; Nakamura, A; Masaki, H; Uozumi, T

    1994-01-01

    The urease of thermophilic Bacillus sp. strain TB-90 is composed of three subunits with molecular masses of 61, 12, and 11 kDa. By using synthetic oligonucleotide probes based on N-terminal amino acid sequences of each subunit, we cloned a 3.2-kb EcoRI fragment of TB-90 genomic DNA. Moreover, we cloned two other DNA fragments by gene walking starting from this fragment. Finally, we reconstructed in vitro a 6.2-kb DNA fragment which expressed catalytically active urease in Escherichia coli by combining these three DNA fragments. Nucleotide sequencing analysis revealed that the urease gene complex consists of nine genes, which were designed ureA, ureB, ureC, ureE, ureF, ureG, ureD, ureH, and ureI in order of arrangement. The structural genes ureA, ureB, and ureC encode the 11-, 12-, and 61-kDa subunits, respectively. The deduced amino acid sequences of UreD, UreE, UreF, and UreG, the gene products of four accessory genes, are homologous to those of the corresponding Ure proteins of Klebsiella aerogenes. UreD, UreF, and UreG were essential for expression of urease activity in E. coli and are suggested to play important roles in the maturation step of the urease in a co- and/or posttranslational manner. On the other hand, UreH and UreI exhibited no significant similarity to the known accessory proteins of other bacteria. However, UreH showed 23% amino acid identity to the Alcaligenes eutrophus HoxN protein, a high-affinity nickel transporter. PMID:8288539

  20. Cloning, sequencing, and expression of thermophilic Bacillus sp. strain TB-90 urease gene complex in Escherichia coli.

    PubMed Central

    Maeda, M; Hidaka, M; Nakamura, A; Masaki, H; Uozumi, T

    1994-01-01

    The urease of thermophilic Bacillus sp. strain TB-90 is composed of three subunits with molecular masses of 61, 12, and 11 kDa. By using synthetic oligonucleotide probes based on N-terminal amino acid sequences of each subunit, we cloned a 3.2-kb EcoRI fragment of TB-90 genomic DNA. Moreover, we cloned two other DNA fragments by gene walking starting from this fragment. Finally, we reconstructed in vitro a 6.2-kb DNA fragment which expressed catalytically active urease in Escherichia coli by combining these three DNA fragments. Nucleotide sequencing analysis revealed that the urease gene complex consists of nine genes, which were designed ureA, ureB, ureC, ureE, ureF, ureG, ureD, ureH, and ureI in order of arrangement. The structural genes ureA, ureB, and ureC encode the 11-, 12-, and 61-kDa subunits, respectively. The deduced amino acid sequences of UreD, UreE, UreF, and UreG, the gene products of four accessory genes, are homologous to those of the corresponding Ure proteins of Klebsiella aerogenes. UreD, UreF, and UreG were essential for expression of urease activity in E. coli and are suggested to play important roles in the maturation step of the urease in a co- and/or posttranslational manner. On the other hand, UreH and UreI exhibited no significant similarity to the known accessory proteins of other bacteria. However, UreH showed 23% amino acid identity to the Alcaligenes eutrophus HoxN protein, a high-affinity nickel transporter. Images PMID:8288539

  1. Experimental Research on the Sterilization of Escherichia Coli and Bacillus Subtilis in Drinking Water by Dielectric Barrier Discharge

    NASA Astrophysics Data System (ADS)

    Li, Yang; Yi, Chengwu; Li, Jingjing; Yi, Rongjie; Wang, Huijuan

    2016-02-01

    The bactericidal effect on the representative type of Gram-negative Escherichia coli (E. coli) and Gram-positive Bacillus subtilis in drinking water was investigated in this paper by using dielectric barrier discharge (DBD) advanced oxidation technology. The sterilizing rates under different conditions of reaction time t, input voltage V, pH value, and initial concentration of bacteria C0 were investigated to figure out the optimum sterilization conditions. Our observations and comparisons of cell morphology alteration by scanning electron microscopy and transmission electron microscopy revealed the sterilization mechanisms. The results showed that the sterilizing rate increased obviously with the extension of reaction time t and the rise of input voltage V. The optimal sterilization effect was achieved when the pH value was 7.1. As the initial concentration of bacteria rose, the sterilizing rate decreased. When the input voltage was 2.2 kV and the initial concentration of bacteria was relatively low, the sterilizing rate almost reached 100% after a certain treatment time in neutral aqueous solution. The reasons for the great damage of cell structure and the killing of bacteria are the oxidation of O3, OH and the accumulation of active species produced by DBD. The article provides a certain theoretical and experimental basis for DBD application in water pollution treatment. supported by the Science and Technology Support Project Plan and Social Development of Jiangsu Province, China (No. BE2011732), the Science and Technology Support Project Plan and Social Development of Zhenjiang, Jiangsu Province, China (No. SH2012013)

  2. Effect of precisely identified mutations in the spoIIAC gene of Bacillus subtilis on the toxicity of the sigma-like gene product to Escherichia coli.

    PubMed

    Yudkin, M D; Harrison, D

    1987-09-01

    Yudkin (1986) has shown that the spoIIAC gene of Bacillus subtilis cannot be cloned in Escherichia coli in such an orientation that it is expressed. This toxicity of the gene product has been attributed to its close homology with the sigma subunit of the E. coli RNA polymerase. The effect of six individual mutations in spoIIAC has now been studied. All six mutant genes could be cloned in E. coli in an orientation that does not allow expression. When in the orientation that permits expression, one mutant gene could not be cloned, and a second substantially hampered growth; both mutations lie in the region that is believed to encode the DNA-binding domain of the protein. By contrast, two missense mutations in the region of the gene thought to encode the domain that binds to the core RNA polymerase rendered the protein harmless in E. coli, as did two nonsense mutations. PMID:3118147

  3. Secretory expression of nattokinase from Bacillus subtilis YF38 in Escherichia coli.

    PubMed

    Liang, Xiaobo; Jia, Shifang; Sun, Yufang; Chen, Meiling; Chen, Xiuzhu; Zhong, Jin; Huan, Liandong

    2007-11-01

    Nattokinase producing bacterium, B. subtilis YF38, was isolated from douchi, using the fibrin plate method. The gene encoding this enzyme was cloned by polymerase chain reaction (PCR). Cytoplasmic expression of this enzyme in E. coli resulted in inactive inclusion bodies. But with the help of two different signal peptides, the native signal peptide of nattokinase and the signal peptide of PelB, active nattokinase was successfully expressed in E. coli with periplasmic secretion, and the nattokinase in culture medium displayed high fibrinolytic activity. The fibrinolytic activity of the expressed enzyme in the culture was determined to reach 260 urokinase units per micro-liter when the recombinant strain was induced by 0.7 mmol l(-1) isopropyl-beta-D- thiogalactopyranoside (IPTG) at 20 degrees C for 20 h, resulting 49.3 mg active enzyme per liter culture. The characteristic of this recombinant nattokinase is comparable to the native nattokinase from B. subtilis YF38. Secretory expression of nattokinase in E. coli would facilitate the development of this enzyme into a therapeutic product for the control and prevention of thrombosis diseases. PMID:17952663

  4. Diarrheagenic Escherichia coli

    PubMed Central

    Nataro, James P.; Kaper, James B.

    1998-01-01

    Escherichia coli is the predominant nonpathogenic facultative flora of the human intestine. Some E. coli strains, however, have developed the ability to cause disease of the gastrointestinal, urinary, or central nervous system in even the most robust human hosts. Diarrheagenic strains of E. coli can be divided into at least six different categories with corresponding distinct pathogenic schemes. Taken together, these organisms probably represent the most common cause of pediatric diarrhea worldwide. Several distinct clinical syndromes accompany infection with diarrheagenic E. coli categories, including traveler’s diarrhea (enterotoxigenic E. coli), hemorrhagic colitis and hemolytic-uremic syndrome (enterohemorrhagic E. coli), persistent diarrhea (enteroaggregative E. coli), and watery diarrhea of infants (enteropathogenic E. coli). This review discusses the current level of understanding of the pathogenesis of the diarrheagenic E. coli strains and describes how their pathogenic schemes underlie the clinical manifestations, diagnostic approach, and epidemiologic investigation of these important pathogens. PMID:9457432

  5. Design and Diversity in Bacterial Chemotaxis: A Comparative Study in Escherichia coli and Bacillus subtilis

    PubMed Central

    2004-01-01

    Comparable processes in different species often involve homologous genes. One question is whether the network structure, in particular the feedback control structure, is also conserved. The bacterial chemotaxis pathways in E. coli and B. subtilis both regulate the same task, namely, excitation and adaptation to environmental signals. Both pathways employ many orthologous genes. Yet how these orthologs contribute to network function in each organism is different. To investigate this problem, we propose what is to our knowledge the first computational model for B. subtilis chemotaxis and compare it to previously published models for chemotaxis in E. coli. The models reveal that the core control strategy for signal processing is the same in both organisms, though in B. subtilis there are two additional feedback loops that provide an additional layer of regulation and robustness. Furthermore, the network structures are different despite the similarity of the proteins in each organism. These results demonstrate the limitations of pathway inferences based solely on homology and suggest that the control strategy is an evolutionarily conserved property. PMID:14966542

  6. Pathogenic Escherichia coli

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Escherichia coli, a member of the Enterobacteriaceae family, is a part of the normal flora of the intestinal tract of humans and a variety of animals. E. coli strains are classified on the basis of antigenic differences in two surface components (serotyping), the somatic antigen (O) of the lipopoly...

  7. PATHOGENIC ESCHERICHIA COLI

    EPA Science Inventory

    Escherichia coli is a bacterial species which inhabits the gastrointestinal tract of man and warm-blooded animals. Because of the ubiquity of this bacterium in the intestinal flora, it serves as an important indicator organism of fecal contamination. E. coli, aside from serving a...

  8. Hypobaric bacteriology: growth, cytoplasmic membrane polarization and total cellular fatty acids in Escherichia coli and Bacillus subtilis

    NASA Astrophysics Data System (ADS)

    Pokorny, N. J.; Boulter-Bitzer, J. I.; Hart, M. M.; Storey, L.; Lee, H.; Trevors, J. T.

    2005-10-01

    Escherichia coli JM109 (Gram-negative) and Bacillus subtilis (Gram-positive) were grown under hypobaric conditions for 19 days at 25 °C to study the effects of 33 and 67 kPa low pressures on selected physiological responses; growth, cytoplasmic membrane polarization (measure of cytoplasmic membrane fluidity) and total cellular fatty acids. In the first experiment, cytoplasmic membrane polarization in B. subtilis increased under both hypobaric conditions, indicating the membrane became more rigid or less fluid. This experiment was repeated and the effect of the hypobaric conditions was not evident as in the first experiment with B. subtilis. In addition, total cellular fatty acids analysis for B. subtilis showed that hypobaric conditions did not alter the ratio of saturated to unsaturated fatty acids. The cytoplasmic membrane remained in the same fluid state in hypobaric grown E. coli cell cultures as in the 101 kPa ambient control cells in both experiments. However, the saturated to unsaturated ratios were altered in E. coli under hypobaric conditions. It is important to note the ratios for E. coli were less than 1, while the ratios for Bacillus were in the 28 50 range. Growth of both species was also measured by colony forming units at the termination of the 19 day experiment. Both bacterial species were capable of growth under hypobaric conditions and no distinct trend emerged as to the effect of hypobaric pressure on bacterial growth and cytoplasmic membrane fluidity.

  9. Identification of four unique clones encoding 10 kDa proteins from Bacillus that cause phenotypic complementation of a phoA mutant strain of Escherichia coli.

    PubMed

    Lee, J W; Edwards, C W; Hulett, F M

    1991-03-01

    A number of clones have been isolated from two Bacillus species which complement the PhoA- phenotype of Escherichia coli mutants under conditions that induce the expression of alkaline phosphatase (APase). These clones were initially thought to carry XPases because the transformed host could hydrolyse a common APase substrate, XP (5-bromo-4-chloro-3-indolyl-phosphate). The sequences of the open reading frames responsible for the phenotypic complementation showed no sequence similarity to ATPases of E. coli, human (bone-liver-kidney, intestinal or placental) or Bacillus. Therefore, these clones were designated as XPA (for X Phosphatase Activity) clones. Four of the clones encoded small (10 kDa), basic, hydrophobic proteins. Two of these, xpaB from B. subtilis 168 and xpaL2 from B. licheniformis MC14, shared 62% identity at both the DNA and the predicted amino acid sequence level. The fact that homologues from two Bacillus strains were cloned indicated that the screen was specific, but not for APase genes. It is clear that phenotypic complementation with cloned DNA from another genus does not ensure the identification of an APase gene. Possible mechanisms for the abnormal phenotypic complementation are discussed. PMID:2033382

  10. Pathogenic Escherichia coli.

    PubMed

    Kaper, James B; Nataro, James P; Mobley, Harry L

    2004-02-01

    Few microorganisms are as versatile as Escherichia coli. An important member of the normal intestinal microflora of humans and other mammals, E. coli has also been widely exploited as a cloning host in recombinant DNA technology. But E. coli is more than just a laboratory workhorse or harmless intestinal inhabitant; it can also be a highly versatile, and frequently deadly, pathogen. Several different E. coli strains cause diverse intestinal and extraintestinal diseases by means of virulence factors that affect a wide range of cellular processes. PMID:15040260

  11. The levanase operon of Bacillus subtilis expressed in Escherichia coli can substitute for the mannose permease in mannose uptake and bacteriophage lambda infection.

    PubMed Central

    Martin-Verstraete, I; Michel, V; Charbit, A

    1996-01-01

    Bacteriophage lambda adsorbs to its Escherichia coli K-12 host by interacting with LamB, a maltose- and maltodextrin-specific porin of the outer membrane. LamB also serves as a receptor for several other bacteriophages. Lambda DNA requires, in addition to LamB, the presence of two bacterial cytoplasmic integral membrane proteins for penetration, namely, the IIC(Man) and IID(Man) proteins of the E. coli mannose transporter, a member of the sugar-specific phosphoenolpyruvate:sugar phosphotransferase system (PTS). The PTS transporters for mannose of E. coli, for fructose of Bacillus subtilis, and for sorbose of Klebsiella pneumoniae were shown to be highly similar to each other but significantly different from other PTS transporters. These three enzyme II complexes are the only ones to possess distinct IIC and IID transmembrane proteins. In the present work, we show that the fructose-specific permease encoded by the levanase operon of B. subtilis is inducible by mannose and allows mannose uptake in B. subtilis as well as in E. coli. Moreover, we show that the B. subtilis permease can substitute for the E. coli mannose permease cytoplasmic membrane components for phage lambda infection. In contrast, a series of other bacteriophages, also using the LamB protein as a cell surface receptor, do not require the mannose transporter for infection. PMID:8955391

  12. Genetic recombination. [Escherichia coli

    SciTech Connect

    Stahl, F.W.

    1987-02-01

    The molecular pathways of gene recombination are explored and compared in studies of the model organisms, Escherichia coli and phase lambda. In the discussion of data from these studies it seems that recombination varies with the genetic idiosyncrasies of the organism and may also vary within a single organism.

  13. The aminoglycoside antibiotic kanamycin damages DNA bases in Escherichia coli: caffeine potentiates the DNA-damaging effects of kanamycin while suppressing cell killing by ciprofloxacin in Escherichia coli and Bacillus anthracis.

    PubMed

    Kang, Tina Manzhu; Yuan, Jessica; Nguyen, Angelyn; Becket, Elinne; Yang, Hanjing; Miller, Jeffrey H

    2012-06-01

    The distribution of mutants in the Keio collection of Escherichia coli gene knockout mutants that display increased sensitivity to the aminoglycosides kanamycin and neomycin indicates that damaged bases resulting from antibiotic action can lead to cell death. Strains lacking one of a number of glycosylases (e.g., AlkA, YzaB, Ogt, KsgA) or other specific repair proteins (AlkB, PhrB, SmbC) are more sensitive to these antibiotics. Mutants lacking AlkB display the strongest sensitivity among the glycosylase- or direct lesion removal-deficient strains. This perhaps suggests the involvement of ethenoadenine adducts, resulting from reactive oxygen species and lipid peroxidation, since AlkB removes this lesion. Other sensitivities displayed by mutants lacking UvrA, polymerase V (Pol V), or components of double-strand break repair indicate that kanamycin results in damaged base pairs that need to be removed or replicated past in order to avoid double-strand breaks that saturate the cellular repair capacity. Caffeine enhances the sensitivities of these repair-deficient strains to kanamycin and neomycin. The gene knockout mutants that display increased sensitivity to caffeine (dnaQ, holC, holD, and priA knockout mutants) indicate that caffeine blocks DNA replication, ultimately leading to double-strand breaks that require recombinational repair by functions encoded by recA, recB, and recC, among others. Additionally, caffeine partially protects cells of both Escherichia coli and Bacillus anthracis from killing by the widely used fluoroquinolone antibiotic ciprofloxacin. PMID:22391551

  14. The Aminoglycoside Antibiotic Kanamycin Damages DNA Bases in Escherichia coli: Caffeine Potentiates the DNA-Damaging Effects of Kanamycin while Suppressing Cell Killing by Ciprofloxacin in Escherichia coli and Bacillus anthracis

    PubMed Central

    Kang, Tina Manzhu; Yuan, Jessica; Nguyen, Angelyn; Becket, Elinne; Yang, Hanjing

    2012-01-01

    The distribution of mutants in the Keio collection of Escherichia coli gene knockout mutants that display increased sensitivity to the aminoglycosides kanamycin and neomycin indicates that damaged bases resulting from antibiotic action can lead to cell death. Strains lacking one of a number of glycosylases (e.g., AlkA, YzaB, Ogt, KsgA) or other specific repair proteins (AlkB, PhrB, SmbC) are more sensitive to these antibiotics. Mutants lacking AlkB display the strongest sensitivity among the glycosylase- or direct lesion removal-deficient strains. This perhaps suggests the involvement of ethenoadenine adducts, resulting from reactive oxygen species and lipid peroxidation, since AlkB removes this lesion. Other sensitivities displayed by mutants lacking UvrA, polymerase V (Pol V), or components of double-strand break repair indicate that kanamycin results in damaged base pairs that need to be removed or replicated past in order to avoid double-strand breaks that saturate the cellular repair capacity. Caffeine enhances the sensitivities of these repair-deficient strains to kanamycin and neomycin. The gene knockout mutants that display increased sensitivity to caffeine (dnaQ, holC, holD, and priA knockout mutants) indicate that caffeine blocks DNA replication, ultimately leading to double-strand breaks that require recombinational repair by functions encoded by recA, recB, and recC, among others. Additionally, caffeine partially protects cells of both Escherichia coli and Bacillus anthracis from killing by the widely used fluoroquinolone antibiotic ciprofloxacin. PMID:22391551

  15. Influence of orally fed a select mixture of Bacillus probiotics on intestinal T-cell migration in weaned MUC4 resistant pigs following Escherichia coli challenge.

    PubMed

    Yang, Gui-Yan; Zhu, Yao-Hong; Zhang, Wei; Zhou, Dong; Zhai, Cong-Cong; Wang, Jiu-Feng

    2016-01-01

    Efficient strategies for treating enteritis caused by F4(+) enterotoxigenic Escherichia coli (ETEC)/verocytotoxigenic Escherichia coli (VTEC)/enteropathogenic E. coli (EPEC) in mucin 4 resistant (MUC4 RR; supposed to be F4ab/ac receptor-negative [F4ab/acR(-)]) pigs remain elusive. A low (3.9 × 10(8) CFU/day) or high (7.8 × 10(8) CFU/day) dose of Bacillus licheniformis and Bacillus subtilis spore mixture (BLS-mix) was orally administered to MUC4 RR piglets for 1 week before F4(+) ETEC/VTEC/EPEC challenge. Orally fed BLS-mix upregulated the expression of TLR4, NOD2, iNOS, IL-8, and IL-22 mRNAs in the small intestine of pigs challenged with E. coli. Expression of chemokine CCL28 and its receptor CCR10 mRNAs was upregulated in the jejunum of pigs pretreated with high-dose BLS-mix. Low-dose BLS-mix pretreatment induced an increase in the proportion of peripheral blood CD4(-)CD8(-) T-cell subpopulations and high-dose BLS-mix induced the expansion of CD4(-)CD8(-) T cells in the inflamed intestine. Immunostaining revealed that considerable IL-7Rα-expressing cells accumulated at the lamina propria of the inflamed intestines after E. coli challenge, even in pigs pretreated with either low- or high-dose BLS-mix, although Western blot analysis of IL-7Rα expression in the intestinal mucosa did not show any change. Our data indicate that oral administration of the probiotic BLS-mix partially ameliorates E. coli-induced enteritis through facilitating upregulation of intestinal IL-22 and IκBα expression, and preventing loss of intestinal epithelial barrier integrity via elevating ZO-1 expression. However, IL-22 also elicits an inflammatory response in inflamed intestines as a result of infection with enteropathogenic bacteria. PMID:27424033

  16. [Comparative Sensitivity of the Luminescent Photobacterium phosphoreum, Escherichia coli, and Bacillus subtilis Strains to Toxic Effects of Carbon-Based Nanomaterials and Metal Nanoparticles].

    PubMed

    Deryabina, D G; Efremova, L V; Karimov, I F; Manukhov, I V; Gnuchikh, E Yu; Miroshnikov, S A

    2016-01-01

    A comparative analysis of the four commercially available and laboratory luminescent sensor strains to the toxic effect of 10 carbon-based nanomatherials (CBNs) and 10 metal nanoparticles (MNPs) was carried out in this study. The bioluminescence inhibition assays with marine Photobacterium phosphoreum and recombinant Escherichia coli strains were varied in minimal toxic concentrations and EC50 values but led to well correlated biotoxicity evaluation for the most active compounds were ranked as Cu > (MgO, CuO) > (fullerenol, graphene oxide). The novel sensor strain Bacillus subtilis EG 168-1 exhibited the highest sensitivity to CBNs and MNPs that increased significantly number of toxic compounds causing the bacterial bioluminescence inhibition effect. PMID:27476206

  17. Isolation and characterization of Bacillus subtilis genes involved in siderophore biosynthesis: relationship between B. subtilis sfpo and Escherichia coli entD genes.

    PubMed Central

    Grossman, T H; Tuckman, M; Ellestad, S; Osburne, M S

    1993-01-01

    In response to iron deprivation, Bacillus subtilis secretes a catecholic siderophore, 2,3-dihydroxybenzoyl glycine, which is similar to the precursor of the Escherichia coli siderophore enterobactin. We isolated two sets of B. subtilis DNA sequences that complemented the mutations of several E. coli siderophore-deficient (ent) mutants with defective enterobactin biosynthesis enzymes. One set contained DNA sequences that complemented only an entD mutation. The second set contained DNA sequences that complemented various combinations of entB, entE, entC, and entA mutations. The two sets of DNA sequences did not appear to overlap. AB. subtilis mutant containing an insertion in the region of the entD homolog grew much more poorly in low-iron medium and with markedly different kinetics. These data indicate that (i) at least five of the siderophore biosynthesis genes of B. subtilis can function in E. coli, (ii) the genetic organization of these siderophore genes in B. subtilis is similar to that in E. coli, and (iii) the B. subtilis entD homolog is required for efficient growth in low-iron medium. The nucleotide sequence of the B. subtilis DNA contained in plasmid pENTA22, a clone expressing the B. subtilis entD homolog, revealed the presence of at least two genes. One gene was identified as sfpo, a previously reported gene involved in the production of surfactin in B. subtilis and which is highly homologous to the E. coli entD gene. We present evidence that the E. coli entD and B. subtilis sfpo genes are interchangeable and that their products are members of a new family of proteins which function in the secretion of peptide molecules. Images PMID:8407792

  18. Recurrent Escherichia coli bacteremia.

    PubMed Central

    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

  19. High-level secretion of a recombinant protein to the culture medium with a Bacillus subtilis twin-arginine translocation system in Escherichia coli.

    PubMed

    Albiniak, Anna M; Matos, Cristina F R O; Branston, Steven D; Freedman, Robert B; Keshavarz-Moore, Eli; Robinson, Colin

    2013-08-01

    The twin-arginine translocation (Tat) system transports folded proteins across the plasma membrane in bacteria, and heterologous proteins can be exported by this pathway if a Tat-type signal peptide is present at the N-terminus. The system thus has potential for biopharmaceutical production in Escherichia coli, where export to the periplasm is often a favoured approach. Previous studies have shown that E. coli cells can export high levels of protein by the Tat pathway, and the protein product accummulates almost exclusively in the periplasm. In this study, we analysed E. coli cells that express the Bacillus subtilis TatAdCd system in place of the native TatABC system. We show that a heterologous model protein, comprising the TorA signal peptide linked to green fluorescent protein (TorA-GFP), is efficiently exported by the TatAdCd system. However, whereas the GFP is exported initially to the periplasm during batch fermentation, the mature protein is increasingly found in the extracellular culture medium. By the end of a 16-h fermentation, ~ 90% of exported GFP is present in the medium as active mature protein. The total protein profiles of the medium and periplasm are essentially identical, confirming that the outer membrane becomes leaky during the fermentation process. The cells are otherwise intact, and there is no large-scale release of cytoplasmic contents. Export levels are relatively high, with ~ 0.35 g GFP·L⁻¹ culture present in the medium. This system thus offers a means of producing recombinant protein in E. coli and harvesting directly from the medium, with potential advantages in terms of ease of purification and downstream processing. PMID:23745597

  20. Cloning, expression and purification of binding domains of lethal factor and protective antigen of Bacillus anthracis in Escherichia coli and evaluation of their related murine antibody.

    PubMed

    Rezaee, Mehdi; Honari, Hossein; Kooshk, Mohammad Reza Ashrafi

    2014-01-01

    Anthrax is common disease between human and animals caused by Bacillus anthracis. The cell binding domain of protective antigen (PAD4) and the binding domain of lethal factor (LFD1) have high immunogenicity potential and always were considered as a vaccine candidate against anthrax. The aims of this study are cloning and expressing of PAD4 and LFD1 in Escherichia coli, purification of the recombinant proteins and determination of their immunogenicity through evaluating of the relative produced polyclonal antibodies in mice. PAD4 and LFD1 genes were cloned in pET28a(+) vector and expressed in E. coli Bl21(DE3)PlysS. Expression and purification of the two recombinant proteins were confirmed by SDS-PAGE and Western blotting techniques. The PAD4 and LFD1 were purified using Ni(+)-NTA affinity chromatography (95-98 %), yielding 37.5 and 45 mg/l of culture, respectively. The antigens were injected three times into mice and production of relative antibodies was evaluated by ELISA test. The results showed that both PAD4 and LFD1 are immunogenic, but LFD1 has higher potential to stimulate Murine immune system. With regard to the high level of LFD1 and PAD4 expression and also significant increment in produced polyclonal antibodies, these recombinant proteins can be considered as a recombinant vaccine candidate against anthrax. PMID:24430302

  1. Recombinant expression of Bacillus anthracis lethal toxin components of Indian isolate in Escherichia coli and determination of its acute toxicity level in mouse model.

    PubMed

    Nagendra, Suryanarayana; Vanlalhmuaka; Verma, Sarika; Tuteja, Urmil; Thavachelvam, Kulanthaivel

    2015-12-15

    Bacillus anthracis lethal toxin (LeTx) is the principle factor responsible for toxaemia and anthrax related death. Lethal toxin consist of two proteins viz protective antigen (PA) and lethal factor which combines in a typical fashion similar to other toxins belonging to A-B toxin super family. The amount of LeTx required to kill a particular organism generally differs among strains owing to their geographical distributions and genetic variation. In the present study, we have cloned PA and LF genes from B. anthracis clinical isolate of Indian origin and expressed them in soluble form employing Escherichia coli expression system. Both the proteins were purified to near homogeneity level using Immobilized metal ion affinity chromatography (IMAC). Further we have used equal ratio of both the proteins to form LeTx and determined its acute toxicity level in Balb/c mice by graphical method of Miller and Tainter. The LD50 value of LeTx by intravenous (i.v) route was found to be 0.97 ± 0.634 mg kg(-1) Balb/c mice. This study highlights the expression of recombinant LeTx from E. coli and assessing its acute toxicity level in experimental mouse model. PMID:26472254

  2. Immunomodulatory effect of non-viable components of probiotic culture stimulated with heat-inactivated Escherichia coli and Bacillus cereus on holoxenic mice

    PubMed Central

    Ditu, L. M.; Chifiriuc, M. C.; Bezirtzoglou, E.; Marutescu, L.; Bleotu, C.; Pelinescu, D.; Mihaescu, G.; Lazar, V.

    2014-01-01

    Background Competition of probiotic bacteria with other species from the intestinal microbiota involves different mechanisms that occur regardless of probiotics’ viability. The objective of this paper was to assess the cytokine serum levels in holoxenic mice after oral administration of non-viable components (NVC) of Enterococcus faecium probiotic culture stimulated with heat-inactivated Escherichia coli and Bacillus cereus in comparison to NVC of unstimulated E. faecium probiotic culture. Methods Probiotic E. faecium CMGb 16 culture, grown in the presence of heat-inactivated cultures of E. coli and B. cereus CMGB 102, was subsequently separated into supernatant (SN) and heat-inactivated cellular sediment (CS) fractions by centrifugation. Each NVC was orally administered to holoxenic mice (balb C mouse strain), in three doses, given at 24 hours. Blood samples were collected from the retinal artery, at 7, 14, and 21 days after the first administration of the NVC. The serum concentrations of IL-12 and tumor necrosis factor-alpha (TNF-α) interleukins were assessed by ELISA method. Results After the oral administration of SN component obtained from the probiotic culture stimulated with heat-inactivated cultures of B. cereus CMGB 102 and E. coli O28, the serum concentrations of IL-12 were maintained higher in the samples collected at 7 and 14 days post-administration. No specific TNF-α profile could be established, depending on stimulated or non-stimulated probiotic culture, NVC fraction, or harvesting time. Conclusion The obtained results demonstrate that non-viable fractions of probiotic bacteria, stimulated by other bacterial species, could induce immunostimulatory effects mediated by cytokines and act, therefore, as immunological adjuvants. PMID:25317114

  3. Oligo-1,6-glucosidase from a thermophile, Bacillus thermoglucosidasius KP1006, was efficiently produced by combinatorial expression of GroEL in Escherichia coli.

    PubMed

    Watanabe, Kunihiko; Fujiwara, Hisashi; Inui, Kazuyo; Suzuki, Yuzuru

    2002-02-01

    To improve the production of oligo-1,6-glucosidase from the obligately thermophilic Bacillus thermoglucosidasius KP1006 in Escherichia coli, the combined expression of oligo-1,6-glucosidase with various chaperone proteins of Hsp (heat-shock protein) 60 team proteins (GroES and GroEL) or Hsp70 team proteins (GrpE, DnaK and DnaJ) from the same thermophile was examined. This attempt was based on the facts that, (i) among glycosyl hydrolases of Family 13, bacillary oligo-1,6-glucosidases share highest homology with yeast alpha-glucosidase, and (ii) this yeast enzyme interacts with GroEL. In B. thermoglucosidasius Hsp60 team proteins, in particular, GroEL brought about a remarkable rise in expression of B. thermoglucosidasius oligo-1,6-glucosidase, while Hsp70 team proteins had no significant effect. The effect of B. thermoglucosidasius GroEL on oligo-1,6-glucosidase expression was supported by the finding that thermally inactivated B. thermoglucosidasius oligo-1,6-glucosidase was revived by B. thermoglucosidasius GroEL. Although the molecular mass of B. thermoglucosidasius oligo-1,6-glucosidase (66 kDa) exceeds the major range of substrates for GroEL proteins, the GroEL molecules probably recognized the alpha/beta motifs contained in the N-terminal domain and the subdomain of the oligo-1,6-glucosidase. Here we show that (i) the production of B. thermoglucosidasius oligo-1,6-glucosidase in E. coli was improved 3.8-fold by Hsp60 team proteins, (ii) the system can function for the expression of other glycosyl hydrolases of Family 13 that have defects in expression and (iii) the combinatorial expression of thermostable proteins with GroEL from the same thermophile in E. coli can increase the production of thermostable enzymes, preventing problems derived from differences in protein biogenesis. PMID:11834128

  4. Application of Escherichia coli phage K1E DNA-dependent RNA polymerase for in vitro RNA synthesis and in vivo protein production in Bacillus megaterium.

    PubMed

    Stammen, Simon; Schuller, Franziska; Dietrich, Sylvia; Gamer, Martin; Biedendieck, Rebekka; Jahn, Dieter

    2010-09-01

    Gene "7" of Escherichia coli phage K1E was proposed to encode a novel DNA-dependent RNA polymerase (RNAP). The corresponding protein was produced recombinantly, purified to apparent homogeneity via affinity chromatography, and successfully employed for in vitro RNA synthesis. Optimal assay conditions (pH 8, 37 degrees C, 10 mM magnesium chloride and 1.3 mM spermidine) were established. The corresponding promoter regions were identified on the phage genome and summarized in a sequence logo. Surprisingly, next to K1E promoters, the SP6 promoter was also recognized efficiently in vitro by K1E RNAP, while the T7 RNAP promoter was not recognized at all. Based on these results, a system for high-yield in vitro RNA synthesis using K1E RNAP was established. The template plasmid is a pUC18 derivative, which enables blue/white screening for positive cloning of the target DNA. Production of more than 5 microg of purified RNA per microgram plasmid DNA was achieved. Finally, in vivo protein production systems for Bacillus megaterium were established based on K1E and SP6 phage RNAP transcription. Up to 61.4 mg g (CDW) (-1) (K1E RNAP) of the reporter protein Gfp was produced in shaking flask cultures of B. megaterium. PMID:20596705

  5. Antibody responses elicited in mice immunized with Bacillus subtilis vaccine strains expressing Stx2B subunit of enterohaemorragic Escherichia coli O157:H7.

    PubMed

    Gomes, P A D P; Bentancor, L V; Paccez, J D; Sbrogio-Almeida, M E; Palermo, M S; Ferreira, R C C; Ferreira, L C S

    2009-04-01

    No effective vaccine or immunotherapy is presently available for patients with the hemolytic uremic syndrome (HUS) induced by Shiga-like toxin (Stx) produced by enterohaemorragic Escherichia coli (EHEC) strains, such as those belonging to the O157:H7 serotype. In this work we evaluated the performance of Bacillus subtilis strains, a harmless spore former gram-positive bacterium species, as a vaccine vehicle for the expression of Stx2B subunit (Stx2B). A recombinant B. subtilis vaccine strain expressing Stx2B under the control of a stress inducible promoter was delivered to BALB/c mice via oral, nasal or subcutaneous routes using both vegetative cells and spores. Mice immunized with vegetative cells by the oral route developed low but specific anti-Stx2B serum IgG and fecal IgA responses while mice immunized with recombinant spores developed anti-Stx2B responses only after administration via the parenteral route. Nonetheless, serum anti-Stx2B antibodies raised in mice immunized with the recombinant B. subtilis strain did not inhibit the toxic effects of the native toxin, both under in vitro and in vivo conditions, suggesting that either the quantity or the quality of the induced immune response did not support an effective neutralization of Stx2 produced by EHEC strains. PMID:24031368

  6. Simultaneous Detection of Listeria monocytogenes, Escherichia coli O157:H7, Bacillus cereus, Salmonella spp., and Staphylococcus aureus in Low-fatted Milk by Multiplex PCR.

    PubMed

    Kim, Ji-Hyun; Rhim, Seong-Ryul; Kim, Kee-Tae; Paik, Hyun-Dong; Lee, Joo-Yeon

    2014-01-01

    A rapid and specific PCR assay for the simultaneous detection of Listeria monocytogenes, Escherichia coli O157:H7, Bacillus cereus, Salmonella spp., and Staphylococcus aureus in foods was developed to reduce the detection time and to increase sensitivity. Multiplex PCR developed in this study produced only actA, fliC, hbl, invA, ileS amplicons, but did not produce any non-specific amplicon. The primer sets successfully amplified the target genes in the multiplex PCR without any non-specific or additional bands on the other strains. The multiplex PCR assays also amplified some target genes from five pathogens, and multiplex amplification was obtained from as little as 1 pg of DNA. According to the results from the sensitivity evaluation, the multiplex PCR developed in this study detected 10 cells/mL of the pathogens inoculated in milk samples, respectively. The results suggested that multiplex PCR was an effective assay demonstrating high specificity for the simultaneous detection of five target pathogens in food system. PMID:26761507

  7. Antibody responses elicited in mice immunized with Bacillus subtilis vaccine strains expressing Stx2B subunit of enterohaemorragic Escherichia coli O157:H7

    PubMed Central

    Gomes, P.A.D.P.; Bentancor, L.V.; Paccez, J.D.; Sbrogio-Almeida, M.E.; Palermo, M.S.; Ferreira, R.C.C.; Ferreira, L.C.S.

    2009-01-01

    No effective vaccine or immunotherapy is presently available for patients with the hemolytic uremic syndrome (HUS) induced by Shiga-like toxin (Stx) produced by enterohaemorragic Escherichia coli (EHEC) strains, such as those belonging to the O157:H7 serotype. In this work we evaluated the performance of Bacillus subtilis strains, a harmless spore former gram-positive bacterium species, as a vaccine vehicle for the expression of Stx2B subunit (Stx2B). A recombinant B. subtilis vaccine strain expressing Stx2B under the control of a stress inducible promoter was delivered to BALB/c mice via oral, nasal or subcutaneous routes using both vegetative cells and spores. Mice immunized with vegetative cells by the oral route developed low but specific anti-Stx2B serum IgG and fecal IgA responses while mice immunized with recombinant spores developed anti-Stx2B responses only after administration via the parenteral route. Nonetheless, serum anti-Stx2B antibodies raised in mice immunized with the recombinant B. subtilis strain did not inhibit the toxic effects of the native toxin, both under in vitro and in vivo conditions, suggesting that either the quantity or the quality of the induced immune response did not support an effective neutralization of Stx2 produced by EHEC strains. PMID:24031368

  8. Simultaneous Detection of Listeria monocytogenes, Escherichia coli O157:H7, Bacillus cereus, Salmonella spp., and Staphylococcus aureus in Low-fatted Milk by Multiplex PCR

    PubMed Central

    Kim, Ji-Hyun; Rhim, Seong-Ryul; Kim, Kee-Tae; Paik, Hyun-Dong

    2014-01-01

    A rapid and specific PCR assay for the simultaneous detection of Listeria monocytogenes, Escherichia coli O157:H7, Bacillus cereus, Salmonella spp., and Staphylococcus aureus in foods was developed to reduce the detection time and to increase sensitivity. Multiplex PCR developed in this study produced only actA, fliC, hbl, invA, ileS amplicons, but did not produce any non-specific amplicon. The primer sets successfully amplified the target genes in the multiplex PCR without any non-specific or additional bands on the other strains. The multiplex PCR assays also amplified some target genes from five pathogens, and multiplex amplification was obtained from as little as 1 pg of DNA. According to the results from the sensitivity evaluation, the multiplex PCR developed in this study detected 10 cells/mL of the pathogens inoculated in milk samples, respectively. The results suggested that multiplex PCR was an effective assay demonstrating high specificity for the simultaneous detection of five target pathogens in food system. PMID:26761507

  9. Effect of chemical fixatives on accurate preservation of Escherichia coli and Bacillus subtilis structure in cells prepared by freeze-substitution

    SciTech Connect

    Graham, L.L.; Beveridge, T.J. )

    1990-04-01

    Five chemical fixatives were evaluated for their ability to accurately preserve bacterial ultrastructure during freeze-substitution of select Escherichia coli and Bacillus subtilis strains. Radioisotopes were specifically incorporated into the peptidoglycan, lipopolysaccharide, and nucleic acids of E. coli SFK11 and W7 and into the peptidoglycan and RNA of B. subtilis 168 and W23. The ease of extraction of radiolabels, as assessed by liquid scintillation counting during all stages of processing for freeze-substitution, was used as an indicator of cell structural integrity and retention of cellular chemical composition. Subsequent visual examination by electron microscopy was used to confirm ultrastructural conformation. The fixatives used were: 2% (wt/vol) osmium tetroxide and 2% (wt/vol) uranyl acetate; 2% (vol/vol) glutaraldehyde and 2% (wt/vol) uranyl acetate; 2% (vol/vol) acrolein and 2% (wt/vol) uranyl acetate; 2% (wt/vol) gallic acid; and 2% (wt/vol) uranyl acetate. All fixatives were prepared in a substitution solvent of anhydrous acetone. Extraction of cellular constituents depended on the chemical fixative used. A combination of 2% osmium tetroxide-2% uranyl acetate or 2% gallic acid alone resulted in optimum fixation as ascertained by least extraction of radiolabels. In both gram-positive and gram-negative organisms, high levels of radiolabel were detected in the processing fluids in which 2% acrolein-2% uranyl acetate, 2% glutaraldehyde-2% uranyl acetate, or 2% uranyl acetate alone were used as fixatives. Ultrastructural variations were observed in cells freeze-substituted in the presence of different chemical fixatives. We recommend the use of osmium tetroxide and uranyl acetate in acetone for routine freeze-substitution of eubacteria, while gallic acid is recommended for use when microanalytical processing necessitates the omission of osmium.

  10. Inactivation of Escherichia coli, Bacteriophage MS2, and Bacillus Spores under UV/H2O2 and UV/Peroxydisulfate Advanced Disinfection Conditions.

    PubMed

    Sun, Peizhe; Tyree, Corey; Huang, Ching-Hua

    2016-04-19

    Ultraviolet light (UV) combined with peroxy chemicals, such as H2O2 and peroxydisulfate (PDS), have been considered potentially highly effective disinfection processes. This study investigated the inactivation of Escherichia coli, bacteriophage MS2, and Bacillus subtilis spores as surrogates for pathogens under UV/H2O2 and UV/PDS conditions, with the aim to provide further understanding of UV-based advanced disinfection processes (ADPs). Results showed that one additional log of inactivation of E. coli was achieved with 0.3 mM H2O2 or PDS at 5.2 × 10(-5) Einstein·L(-1) photo fluence (at 254 nm) compared with UV irradiation alone. Addition of H2O2 and PDS greatly enhanced the inactivation rate of MS2 by around 15 folds and 3 folds, respectively, whereas the inactivation of B. subtilis spores was slightly enhanced. Reactive species responsible for the inactivation were identified to be •OH, SO4(·-), and CO3(·-) based on manipulation of solution conditions. The CT value of each reactive species was calculated with respect to each microbial surrogate, which showed that the disinfection efficacy ranked as •OH > SO4(·-) > CO3(·-) ≫ O2(·-)/HO2(·). A comprehensive dynamic model was developed and successfully predicted the inactivation of the microbial surrogates in surface water and wastewater matrices. The concepts of UV-efficiency and EE/O were employed to provide a cost-effective evaluation for UV-based ADPs. Overall, the present study suggests that it will be beneficial to upgrade UV disinfection to UV/H2O2 ADP for the inactivation of viral pathogens. PMID:27014964

  11. Cloning and sequencing of a cellobiose phosphotransferase system operon from Bacillus stearothermophilus XL-65-6 and functional expression in Escherichia coli.

    PubMed Central

    Lai, X; Ingram, L O

    1993-01-01

    Cellulolytic strains of Bacillus stearothermophilus were isolated from nature and screened for the presence of activities associated with the degradation of plant cell walls. One isolate (strain XL-65-6) which exhibited strong activities with 4-methylumbelliferyl-beta-D-glucopyranoside (MUG) and 4-methylumbelliferyl-beta-D-cellobiopyranoside (MUC) was used to construct a gene library in Escherichia coli. Clones degrading these model substrates were found to encode the cellobiose-specific genes of the phosphoenolpyruvate-dependent phosphotransferase system (PTS). Both MUG and MUC activities were present together, and both activities were lost concurrently during subcloning experiments. A functional E. coli ptsI gene was required for MUC and MUG activities (presumably a ptsH gene also). The DNA fragment from B. stearothermophilus contained four open reading frames which appear to form a cel operon. Intergenic stop codons for celA, celB, and celC overlapped the ribosomal binding sites of the respective downstream genes. Frameshift mutations or deletions in celA, celB, and celD were individually shown to result in a loss of MUC and MUG activities. On the basis of amino acid sequence homology and hydropathy plots of translated sequences, celA and celB were identified as encoding PTS enzyme II and celD was identified as encoding PTS enzyme III. These translated sequences were remarkably similar to their respective E. coli homologs for cellobiose transport. No reported sequences exhibited a high level of homology with the celC gene product. The predicted carboxy-terminal region for celC was similar to the corresponding region of E. coli celF, a phospho-beta-glucosidase. An incomplete regulatory gene (celR) and proposed promoter sequence were located 5' to the proposed cel operon. A stem-loop resembling a rho-independent terminator was present immediately downstream from celD. These results indicate that B. stearothermophilus XL-65-6 contains a cellobiose-specific PTS for

  12. Enterohemorrhagic Escherichia coli Adhesins.

    PubMed

    McWilliams, Brian D; Torres, Alfredo G

    2014-06-01

    Adhesins are a group of proteins in enterohemorrhagic Escherichia coli (EHEC) that are involved in the attachment or colonization of this pathogen to abiotic (plastic or steel) and biological surfaces, such as those found in bovine and human intestines. This review provides the most up-to-date information on these essential adhesion factors, summarizing important historical discoveries and analyzing the current and future state of this research. In doing so, the proteins intimin and Tir are discussed in depth, especially regarding their role in the development of attaching and effacing lesions and in EHEC virulence. Further, a series of fimbrial proteins (Lpf1, Lpf2, curli, ECP, F9, ELF, Sfp, HCP, and type 1 fimbria) are also described, emphasizing their various contributions to adherence and colonization of different surfaces and their potential use as genetic markers in detection and classification of different EHEC serotypes. This review also discusses the role of several autotransporter proteins (EhaA-D, EspP, Saa and Sab, and Cah), as well as other proteins associated with adherence, such as flagella, EibG, Iha, and OmpA. While these proteins have all been studied to varying degrees, all of the adhesins summarized in this article have been linked to different stages of the EHEC life cycle, making them good targets for the development of more effective diagnostics and therapeutics. PMID:26103974

  13. Emerging Enteropathogenic Escherichia coli Strains?

    PubMed Central

    Irino, Kinue; Girão, Dennys M.; Girão, Valéria B.C.; Guth, Beatriz E.C.; Vaz, Tânia M.I.; Moreira, Fabiana C.; Chinarelli, Silvia H.; Vieira, Mônica A.M.

    2004-01-01

    Escherichia coli strains of nonenteropathogenic serogroups carrying eae but lacking the enteropathogenic E. coli adherence factor plasmid and Shiga toxin DNA probe sequences were isolated from patients (children, adults, and AIDS patients) with and without diarrhea in Brazil. Although diverse in phenotype and genotype, some strains are potentially diarrheagenic. PMID:15504277

  14. Molecular cloning of an endoglucanase gene from an alkalophilic bacillus sp. and its expression in escherichia coli

    SciTech Connect

    Kim, J.M.; Kong, I.S.; Yu, J.H.

    1987-11-01

    One of the cellulase genes from alkalophilic Bacillus sp. strain N-4 was cloned in pBR322. A recombinant plasmid, pYBC107, expressing carboxymethyl cellulase (CMCase) was isolated, and the size of the cloned HindIII fragment was found to be 5.5 kilobases. The restriction map of pYBC107 showed a different pattern from those of pNKI and pNKII. When the HindIII fragment from pYBC107 was subcloned into pYEJ001, there was a 3.8-fold increase in CMCase activity over that observed with pYBC107. Plasmid pYBC108 constructed by treatment of pYBC107 with HindIII and ECORI expressed the CMCase activity, although to a limited extend. To verify the originality of cloned pYBC107 from Bacillus sp;, the authors analyzed the restriction digest by Southern blotting.

  15. Physicochemical interaction of Escherichia coli cell envelopes and Bacillus subtilis cell walls with two clays and ability of the composite to immobilize heavy metals from solution.

    PubMed Central

    Walker, S G; Flemming, C A; Ferris, F G; Beveridge, T J; Bailey, G W

    1989-01-01

    Isolated Escherichia coli K-12 cell envelopes or Bacillus subtilis 168 cell walls were reacted with smectite or kaolinite clay in distilled deionized water (pH 6.0); unbound envelopes or walls were separated by sucrose density gradient centrifugation, and the extent of adsorption was calculated. At saturation, both clays adsorbed approximately 1.0 mg (dry weight) of envelopes or walls per mg (dry weight) of clay. Clays showed a preference for edge-on orientation with both walls and envelopes, which was indicative of an aluminum polynuclear bridging mechanism between the wall or envelope surface and the clay edge. The addition of heavy metals increased the incidence of planar surface orientations, which suggested that multivalent metal cation bridging was coming into play and was of increasing importance. The metal-binding capacity of isolated envelopes, walls, clays, and envelope-clay or wall-clay mixtures was determined by atomic absorption spectroscopy after exposure to aqueous 5.0 mM Ag+, Cu2+, Cd2+, Ni2+, Pb2+, Zn2+, and Cr3+ nitrate salt solutions at pHs determined by the buffering capacity of wall, envelope, clay, or composite system. The order of metal uptake was walls greater than envelopes greater than smectite clay greater than kaolinite clay for the individual components, and walls plus smectite greater than walls plus kaolinite greater than envelopes plus smectite greater than envelopes plus kaolinite for the mixtures. On a dry-weight basis, the envelope-clay and wall-clay mixtures bound 20 to 90% less metal than equal amounts of the individual components did.(ABSTRACT TRUNCATED AT 250 WORDS) Images PMID:2516433

  16. Characterization of chito-oligosaccharides prepared by chitosanolysis with the aid of papain and Pronase, and their bactericidal action against Bacillus cereus and Escherichia coli

    PubMed Central

    2005-01-01

    Papain (from papaya latex; EC 3.4.22.2) and Pronase (from Streptomyces griseus; EC 3.4.24.31) caused optimum depolymerization of chitosan at pH 3.5 and 37 °C, resulting in LMMC (low molecular mass chitosan) and chito-oligomeric–monomeric mixture. The yield of the latter was 14–16% and 14–19% respectively for papain- and Pronase-catalysed reactions, depending on the reaction time (1–5 h). HPLC revealed the presence of monomer(s) and oligomers of DP (degree of polymerization) 2–6, which was also confirmed by matrix-assisted laser-desorption ionization–time-of-flight MS. Along with the chito-oligomers, the appearance of only GlcNAc (N-acetylglucosamine) in Pronase-catalysed chitosanolysis was indicative of its different action pattern compared with papain. Fourier-transform infrared, liquid-state 13C-NMR spectra and CD analyses of chito-oligomeric–monomeric mixture indicated the release of GlcNAc/GlcNAc-rich oligomers. The monomeric sequence at the non-reducing ends of chito-oligomers was elucidated using N-acetylglucosaminidase. The chito-oligomeric–monomeric mixture showed better growth inhibitory activity towards Bacillus cereus and Escherichia coli compared with native chitosan. Optimum growth inhibition was observed with chito-oligomers of higher DP having low degree of acetylation. The latter caused pore formation and permeabilization of the cell wall of B. cereus, whereas blockage of nutrient flow due to the aggregation of chito-oligomers–monomers was responsible for the growth inhibition and lysis of E. coli, which were evidenced by scanning electron microscopy analysis. The spillage of cytoplasmic enzymes and native PAGE of the cell-free supernatant of B. cereus treated with chito-oligomeric–monomeric mixture further confirmed bactericidal activity of the latter. Use of papain and Pronase, which are inexpensive and easily available, for chitosanolysis, is of commercial importance, as the products released are of considerable biomedical

  17. Characterization of chito-oligosaccharides prepared by chitosanolysis with the aid of papain and Pronase, and their bactericidal action against Bacillus cereus and Escherichia coli.

    PubMed

    Vishu Kumar, Acharya B; Varadaraj, Mandyam C; Gowda, Lalitha R; Tharanathan, Rudrapatnam N

    2005-10-15

    Papain (from papaya latex; EC 3.4.22.2) and Pronase (from Streptomyces griseus; EC 3.4.24.31) caused optimum depolymerization of chitosan at pH 3.5 and 37 degrees C, resulting in LMMC (low molecular mass chitosan) and chito-oligomeric-monomeric mixture. The yield of the latter was 14-16% and 14-19% respectively for papain- and Pronase-catalysed reactions, depending on the reaction time (1-5 h). HPLC revealed the presence of monomer(s) and oligomers of DP (degree of polymerization) 2-6, which was also confirmed by matrix-assisted laser-desorption ionization-time-of-flight MS. Along with the chito-oligomers, the appearance of only GlcNAc (N-acetylglucosamine) in Pronase-catalysed chitosanolysis was indicative of its different action pattern compared with papain. Fourier-transform infrared, liquid-state 13C-NMR spectra and CD analyses of chito-oligomeric-monomeric mixture indicated the release of GlcNAc/GlcNAc-rich oligomers. The monomeric sequence at the non-reducing ends of chito-oligomers was elucidated using N-acetylglucosaminidase. The chito-oligomeric-monomeric mixture showed better growth inhibitory activity towards Bacillus cereus and Escherichia coli compared with native chitosan. Optimum growth inhibition was observed with chito-oligomers of higher DP having low degree of acetylation. The latter caused pore formation and permeabilization of the cell wall of B. cereus, whereas blockage of nutrient flow due to the aggregation of chito-oligomers-monomers was responsible for the growth inhibition and lysis of E. coli, which were evidenced by scanning electron microscopy analysis. The spillage of cytoplasmic enzymes and native PAGE of the cell-free supernatant of B. cereus treated with chito-oligomeric-monomeric mixture further confirmed bactericidal activity of the latter. Use of papain and Pronase, which are inexpensive and easily available, for chitosanolysis, is of commercial importance, as the products released are of considerable biomedical value. PMID

  18. Cloning of the Bacillus subtilis DLG beta-1,4-glucanase gene and its expression in Escherichia coli and B. subtilis.

    PubMed Central

    Robson, L M; Chambliss, G H

    1986-01-01

    The gene encoding beta-1,4-glucanase in Bacillus subtilis DLG was cloned into both Escherichia coli C600SF8 and B. subtilis PSL1, which does not naturally produce beta-1,4-glucanase, with the shuttle vector pPL1202. This enzyme is capable of degrading both carboxymethyl cellulose and trinitrophenyl carboxymethyl cellulose, but not more crystalline cellulosic substrates (L. M. Robson and G. H. Chambliss, Appl. Environ. Microbiol. 47:1039-1046, 1984). The beta-1,4-glucanase gene was localized to a 2-kilobase (kb) EcoRI-HindIII fragment contained within a 3-kb EcoRI chromosomal DNA fragment of B. subtilis DLG. Recombinant plasmids pLG4000, pLG4001a, pLG4001b, and pLG4002, carrying this 2-kb DNA fragment, were stably maintained in both hosts, and the beta-1,4-glucanase gene was expressed in both. The 3-kb EcoRI fragment apparently contained the beta-1,4-glucanase gene promoter, since transformed strains of B. subtilis PSL1 produced the enzyme in the same temporal fashion as the natural host B. subtilis DLG. B. subtilis DLG produced a 35,200-dalton exocellular beta-1,4-glucanase; intracellular beta-1,4-glucanase was undetectable. E. coli C600SF8 transformants carrying any of the four recombinant plasmids produced two active forms of beta-1,4-glucanase, an intracellular form (51,000 +/- 900 daltons) and a cell-associated form (39,000 +/- 400 daltons). Free exocellular enzyme was negligible. In contrast, B. subtilis PSL1 transformed with recombinant plasmid pLG4001b produced three distinct sizes of active exocellular beta-1,4-glucanase: approximately 36,000, approximately 35,200, and approximately 33,500 daltons. Additionally, B. subtilis PSL1(pLG4001b) transformants contained a small amount (5% or less) of active intracellular beta-1,4-glucanase of three distinct sizes: approximately 50,500, approximately 38,500 and approximately 36,000 daltons. The largest form of beta-1,4-glucanase seen in both transformants may be the primary, unprocessed translation product of the

  19. EXTRAINTESTINAL PATHOGENIC ESCHERICHIA COLI (EXPEC)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Extraintestinal pathogenic Escherichia coli (ExPEC) possess virulence traits that allow them to invade, colonize, and induce disease in bodily sites outside of the gastrointestinal tract. Human diseases caused by ExPEC include urinary tract infections, neonatal meningitis, sepsis, pneumonia, surgic...

  20. Shiga Toxin Producing Escherichia coli.

    PubMed

    Bryan, Allen; Youngster, Ilan; McAdam, Alexander J

    2015-06-01

    Shiga toxin-producing Escherichia coli (STEC) is among the common causes of foodborne gastroenteritis. STEC is defined by the production of specific toxins, but within this pathotype there is a diverse group of organisms. This diversity has important consequences for understanding the pathogenesis of the organism, as well as for selecting the optimum strategy for diagnostic testing in the clinical laboratory. This review includes discussions of the mechanisms of pathogenesis, the range of manifestations of infection, and the several different methods of laboratory detection of Shiga toxin-producing E coli. PMID:26004641

  1. Enhanced production of carboxymethylcellulase of a marine microorganism, Bacillus subtilis subsp. subtilis A-53 in a pilot-scaled bioreactor by a recombinant Escherichia coli JM109/A-53 from rice bran.

    PubMed

    Lee, Eun-Jung; Lee, Bo-Hwa; Kim, Bo-Kyung; Lee, Jin-Woo

    2013-05-01

    A gene encoding the carboxymethylcellulase (CMCase) of a marine bacterium, Bacillus subtilis subsp. subtilis A-53, was cloned in Escherichia coli JMB109 and the recombinant strain was named as E. coli JMB109/A-53. The optimal conditions of rice bran, ammonium chloride, and initial pH of the medium for cell growth, extracted by Design Expert Software based on response surface methodology, were 100.0 g/l, 7.5 g/l, and 7.0, respectively, whereas those for production of CMCase were 100.0 g/l, 7.5 g/l, and 8.0. The optimal temperatures for cell growth and the production of CMCase by E. coli JM109/A-53 were found to be and 40 and 35 °C, respectively. The optimal agitation speed and aeration rate of a 7 l bioreactor for cell growth were 400 rpm and 1.5 vvm, whereas those for production of CMCase were 400 rpm and 0.5 vvm. The optimal inner pressure for cell growth was 0.06 MPa, which was the same as that for production of CMCase. The production of CMCase by E. coli JM109/A-53 under optimized conditions was 880.2 U/ml, which was 2.9 times higher than that before optimization. In this study, rice bran and ammonium chloride were developed as carbon and nitrogen source for production of CMCase by a recombinant E. coli JM109/A-53 and the productivity of E. coli JM109/A-53 was 5.9 times higher than that of B. subtilis subp. subtilis A-53. PMID:23334472

  2. Expression, purification, and characterization of a 2,3-dihydroxybiphenyl-1,2-dioxygenase from Bacillus sp. JF8 in Escherichia coli.

    PubMed

    Bian, Lin; Shuai, Jian-Jun; Xiong, Fei; Peng, Ri-He; Yao, Quan-Hong; Xiong, Ai-Sheng

    2012-03-01

    2,3-Dihydroxybiphenyl-1,2-dioxygenase plays an important role in the degradation of polychlorinated biphenyls. The gene (BsbphCI) encoding a 2,3-DHBP dioxygenase from Bacillus sp. JF8 is 960 bp. We synthesized a 960 bp BsbphCI gene encoding a 2,3-DHBP dioxygenase derived from Bacillus sp. JF8 and expressed it in Escherichiacoli. The recombinant protein was about 36 kDa, confirmed by SDS-PAGE. The concentration of the purified protein was about 1.8 mg/mL. With 2,3-DHBP as a substrate, the optimal temperature for enzyme activity at pH 8.5 was 50 °C. The optimal pH for the 2,3-DHBP dioxygenase was 8.5. The enzyme retained 33% activity after heating at 60 °C for 60 min. We found that Cu(2+), K(+), Zn(2+), Mg(2+), Ni(2+), Co(2+), and Cd(2+) activated the enzyme. However, Ca(2+), Fe(2+), Li(+), and Cr(3+) inhibited it. Enzyme activity was reduced by exposure to H(2)O(2), SDS, and KI. The results of HPLC indicated that the transgenic E. coli strain with the BsbphCI gene degraded 2,3-DHBP more quickly than the wild type strain. PMID:22342724

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

    EPA Science Inventory

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

  4. High level extracellular production of a truncated alkaline β-mannanase from alkaliphilic Bacillus sp. N16-5 in Escherichia coli by the optimization of induction condition and fed-batch fermentation.

    PubMed

    Zheng, Hongchen; Yu, Zhenxiao; Fu, Xiaoping; Li, Shufang; Xu, Jianyong; Song, Hui; Ma, Yanhe

    2016-07-01

    To improve the extracellular production of alkaline β-mannanase from alkaliphilic Bacillus sp. N16-5 in Escherichia coli, two truncated recombinant mannanases (32a-ManAR2 and 22b-ManAR2) were obtained. Compared with the full-length mannanases (32a-ManAR1 and 22b-ManAR1), the truncated mannanases not only showed higher secretion rate, but also exhibited higher thermostability and alkalistability. The K m value (11 mg/mL) of 32a-ManAR2 was higher than that (1.46 mg/mL) of 32a-ManAR1. The specific activity of 22b-ManAR2 was 2.7 times higher than that of 22b-ManAR1. 22b-ManAR2 showed the highest k cat/K m value of 602.7 ml/mg s. The parameters of induction for recombinant mannanase production of E. coli BL21 (pET32a-manAR2) and E. coli BL21 (pET22b-manAR2) were subsequently optimized. The yield of soluble mannanase was found to be enhanced with lower induction temperature (25 °C), lower IPTG concentration (0.01-0.05 mM), and Triton X-100 supplement (0.1 %) in a shake flask. Moreover, a one-time feeding strategy and Triton X-100 supplement were applied in production of 22b-ManAR2 in a 10 L fermentor. The productivity of the total soluble mannanase reached 9284.64 U/mL with the extracellular rate of 74 % at 46 h of fermentation, which was the highest productive level of alkaline β-mannanase in recombinant E. coli to date. PMID:27130461

  5. Nonchemotactic Mutants of Escherichia coli

    PubMed Central

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

    1967-01-01

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

  6. Peptidoglycan Hydrolases of Escherichia coli

    PubMed Central

    van Heijenoort, Jean

    2011-01-01

    Summary: The review summarizes the abundant information on the 35 identified peptidoglycan (PG) hydrolases of Escherichia coli classified into 12 distinct families, including mainly glycosidases, peptidases, and amidases. An attempt is also made to critically assess their functions in PG maturation, turnover, elongation, septation, and recycling as well as in cell autolysis. There is at least one hydrolytic activity for each bond linking PG components, and most hydrolase genes were identified. Few hydrolases appear to be individually essential. The crystal structures and reaction mechanisms of certain hydrolases having defined functions were investigated. However, our knowledge of the biochemical properties of most hydrolases still remains fragmentary, and that of their cellular functions remains elusive. Owing to redundancy, PG hydrolases far outnumber the enzymes of PG biosynthesis. The presence of the two sets of enzymes acting on the PG bonds raises the question of their functional correlations. It is difficult to understand why E. coli keeps such a large set of PG hydrolases. The subtle differences in substrate specificities between the isoenzymes of each family certainly reflect a variety of as-yet-unidentified physiological functions. Their study will be a far more difficult challenge than that of the steps of the PG biosynthesis pathway. PMID:22126997

  7. Structure of Escherichia coli tryptophanase.

    PubMed

    Ku, Shao Yang; Yip, Patrick; Howell, P Lynne

    2006-07-01

    Pyridoxal 5'-phosphate (PLP) dependent tryptophanase has been isolated from Escherichia coli and its crystal structure has been determined. The structure shares the same fold with and has similar quaternary structure to Proteus vulgaris tryptophanase and tyrosine-phenol lyase, but is found in a closed conformation when compared with these two enzymes. The tryptophanase structure, solved in its apo form, does not have covalent PLP bound in the active site, but two sulfate ions. The sulfate ions occupy the phosphoryl-binding site of PLP and the binding site of the alpha-carboxyl of the natural substrate tryptophan. One of the sulfate ions makes extensive interactions with both the transferase and PLP-binding domains of the protein and appears to be responsible for holding the enzyme in its closed conformation. Based on the sulfate density and the structure of the P. vulgaris enzyme, PLP and the substrate tryptophan were modeled into the active site. The resulting model is consistent with the roles of Arg419 in orienting the substrate to PLP and acidifying the alpha-proton of the substrate for beta-elimination, Lys269 in the formation and decomposition of the PLP quinonoid intermediate, Arg230 in orienting the substrate-PLP intermediates in the optimal conformation for catalysis, and His463 and Tyr74 in determining substrate specificity and suggests that the closed conformation observed in the structure could be induced by substrate binding and that significant conformational changes occur during catalysis. A catalytic mechanism for tryptophanase is proposed. Since E. coli tryptophanase has resisted forming diffraction-quality crystals for many years, the molecular surface of tryptophanase has been analyzed in various crystal forms and it was rationalized that strong crystal contacts occur on the flat surface of the protein and that the size of crystal contact surface seems to correlate with the diffraction quality of the crystal. PMID:16790938

  8. Structure of Escherichia Coli Tryptophanase

    SciTech Connect

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

    2006-01-01

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

  9. Succinate production in Escherichia coli

    PubMed Central

    Thakker, Chandresh; Martínez, Irene; San, Ka-Yiu; Bennett, George N.

    2012-01-01

    Succinate has been recognized as an important platform chemical that can be produced from biomass. While a number of organisms are capable of succinate production naturally, this review focuses on the engineering of Escherichia coli for production of the four-carbon dicarboxylic acid. Important features of a succinate production system are to achieve optimal balance of reducing equivalents generated by consumption of the feedstock, while maximizing the amount of carbon that is channeled to the product. Aerobic and anaerobic production strains have been developed and applied to production from glucose as well as other abundant carbon sources. Metabolic engineering methods and strain evolution have been used and supplemented by the recent application of systems biology and in silico modeling tools to construct optimal production strains. The metabolic capacity of the production strain, as well as the requirement for efficient recovery of succinate and the reliability of the performance under scale-up are important in the overall process. The costs of the overall biorefinery compatible process will determine the economical commercialization of succinate and its impact in larger chemical markets. PMID:21932253

  10. Dihydropteridine reductase from Escherichia coli.

    PubMed Central

    Vasudevan, S G; Shaw, D C; Armarego, W L

    1988-01-01

    A dihydropteridine reductase from Escherichia coli was purified to apparent homogeneity. It is a dimeric enzyme with identical subunits (Mr 27000) and a free N-terminal group. It can use NADH (Vmax./Km 3.36 s-1) and NADPH (Vmax./Km 1.07 s-1) when 6-methyldihydro-(6H)-pterin is the second substrate, as well as quinonoid dihydro-(6H)-biopterin (Vmax./Km 0.69 s-1), dihydro-(6H)-neopterin (Vmax./Km 0.58 s-1), dihydro-(6H)-monapterin 0.66 s-1), 6-methyldihydro-(6H)-pterin and cis-6,7-dimethyldihydro-(6H)-pterin (Vmax./Km 0.66 s-1) when NADH is the second substrate. The pure reductase has a yellow colour and contains bound FAD. The enzyme also has pterin-independent NADH and NADPH oxidoreductase activities when potassium ferricyanide is the electron acceptor. Images Fig. 2. PMID:3060113

  11. Escherichia coli survival in waters: Temperature dependence

    EPA Science Inventory

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

  12. Strategies for Protein Overproduction in Escherichia coli.

    ERIC Educational Resources Information Center

    Mott, John E.

    1984-01-01

    Examines heterologous expression in Escherichia coli and the role of regulatory sequences which control gene expression at transcription resulting in abundant production of messenger RNA and regulatory sequences in mRNA which promote efficient translation. Also examines the role of E. coli cells in stabilizing mRNA and protein that is…

  13. A DNA structural atlas for Escherichia coli.

    PubMed

    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

  14. Clinical implications of enteroadherent Escherichia coli.

    PubMed

    Arenas-Hernández, Margarita M P; Martínez-Laguna, Ygnacio; Torres, Alfredo G

    2012-10-01

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

  15. Clinical Implications of Enteroadherent Escherichia coli

    PubMed Central

    Arenas-Hernández, Margarita M.P.; Martínez-Laguna, Ygnacio; Torres, Alfredo G.

    2012-01-01

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

  16. Infection strategies of enteric pathogenic Escherichia coli

    PubMed Central

    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 allow enteric E. coli to colonize and cause disease in the human host are examined and for two of the pathotypes that express a type 3 secretion system (T3SS) we discuss the complex interplay between translocated effectors and manipulation of host cell signaling pathways that occurs during infection. PMID:22555463

  17. Fosfomycin Resistance in Escherichia coli, Pennsylvania, USA

    PubMed Central

    Alrowais, Hind; McElheny, Christi L.; Spychala, Caressa N.; Sastry, Sangeeta; Guo, Qinglan; Butt, Adeel A.

    2015-01-01

    Fosfomycin resistance in Escherichia coli is rare in the United States. An extended-spectrum β-lactamase–producing E. coli clinical strain identified in Pennsylvania, USA, showed high-level fosfomycin resistance caused by the fosA3 gene. The IncFII plasmid carrying this gene had a structure similar to those found in China, where fosfomycin resistance is commonly described. PMID:26488485

  18. The ars operon of Escherichia coli confers arsenical and antimonial resistance.

    PubMed Central

    Carlin, A; Shi, W; Dey, S; Rosen, B P

    1995-01-01

    The chromosomally encoded arsenical resistance (ars) operon subcloned into a multicopy plasmid was found to confer a moderate level of resistance to arsenite and antimonite in Escherichia coli. When the operon was deleted from the chromosome, the cells exhibited hypersensitivity to arsenite, antimonite, and arsenate. Expression of the ars genes was inducible by arsenite. By Southern hybridization, the operon was found in all strains of E. coli examined but not in Salmonella typhimurium, Pseudomonas aeruginosa, or Bacillus subtilis. PMID:7860609

  19. Escherichia Coli--Key to Modern Genetics.

    ERIC Educational Resources Information Center

    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.…

  20. Detection of O antigens in Escherichia coli

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 ...

  1. Escherichia coli and Sudden Infant Death Syndrome

    PubMed Central

    Bettelheim, Karl A.; Goldwater, Paul N.

    2015-01-01

    This review examines the association of strains of Escherichia coli with sudden infant death syndrome (SIDS) and the possible role these bacteria play in this enigmatic condition. The review addresses evidence for E. coli in SIDS infants, potential sources of E. coli in the environment, colonization by commensal and pathogenic strains, the variety of currently accepted pathotypes, and how these pathotypes could compromise intestinal integrity and induce inflammation. Both intestinal and extraintestinal pathotypes are compared in relation to the apparent liability in which virulence traits can be gained or lost by strains of E. coli. The way in which E. coli infections fit with current views on infant sleeping position and other SIDS risk factors is highlighted. PMID:26191064

  2. Mechanism of Sperm Immobilization by Escherichia coli

    PubMed Central

    Prabha, Vijay; Sandhu, Ravneet; Kaur, Siftjit; Kaur, Kiranjeet; Sarwal, Abha; Mavuduru, Ravimohan S.; Singh, Shravan Kumar

    2010-01-01

    Aim. To explore the influence of Escherichia coli on the motility of human spermatozoa and its possible mechanism. Methods. Highly motile preparations of spermatozoa from normozoospermic patients were coincubated with Escherichia coli for 4 hours. At 1, 2 and 4 hours of incubation, sperm motility was determined. The factor responsible for sperm immobilization without agglutination was isolated and purified from filtrates. Results. This report confirms the immobilization of spermatozoa by E. coli and demonstrates sperm immobilization factor (SIF) excreted by E. coli. Further this factor was purified by ammonium sulfate precipitation, gel permeation chromatography, and ion-exchange chromatography. Purified SIF (56 kDa) caused instant immobilization without agglutination of human spermatozoa at 800 μg/mL and death at 2.1 mg/mL. Spermatozoa incubated with SIF revealed multiple and profound alterations involving all superficial structures of spermatozoa as observed by scanning electron microscopy. Conclusion. In conclusion, these results have shown immobilization of spermatozoa by E. coli and demonstrate a factor (SIF) produced and secreted by E. coli which causes variable structural damage as probable morphological correlates of immobilization. PMID:20379358

  3. The flexible feedstock concept in Industrial Biotechnology: Metabolic engineering of Escherichia coli, Corynebacterium glutamicum, Pseudomonas, Bacillus and yeast strains for access to alternative carbon sources.

    PubMed

    Wendisch, Volker F; Brito, Luciana Fernandes; Gil Lopez, Marina; Hennig, Guido; Pfeifenschneider, Johannes; Sgobba, Elvira; Veldmann, Kareen H

    2016-09-20

    Most biotechnological processes are based on glucose that is either present in molasses or generated from starch by enzymatic hydrolysis. At the very high, million-ton scale production volumes, for instance for fermentative production of the biofuel ethanol or of commodity chemicals such as organic acids and amino acids, competing uses of carbon sources e.g. in human and animal nutrition have to be taken into account. Thus, the biotechnological production hosts E. coli, C. glutamicum, pseudomonads, bacilli and Baker's yeast used in these large scale processes have been engineered for efficient utilization of alternative carbon sources. This flexible feedstock concept is central to the use of non-glucose second and third generation feedstocks in the emerging bioeconomy. The metabolic engineering efforts to broaden the substrate scope of E. coli, C. glutamicum, pseudomonads, B. subtilis and yeasts to include non-native carbon sources will be reviewed. Strategies to enable simultaneous consumption of mixtures of native and non-native carbon sources present in biomass hydrolysates will be summarized and a perspective on how to further increase feedstock flexibility for the realization of biorefinery processes will be given. PMID:27491712

  4. Diagnosisand Investigation of Diarrheagenic Escherichia coli.

    PubMed

    Nataro, J P; Martinez, J

    1998-01-01

    Although most Escherichia coli are harmless commensals of the human intestine, certain specific, highly-adapted E. coli strains are capable of causing urinary tract, systemic or enteric/diarrheagenic infection. Diarrheagenic E coli are divided into six distinct categories, or pathotypes, each with a distinct pathogenic scheme (Table 1). Combined, diarrheagenic E coli have emerged as perhaps the most important enteric pathogens of man. In the developing world, the E coli categories account for more cases of gastroenteiltis among infants than any other cause (1) In addition, E coli are also the most common cause of traveller's diarrhea, which afflicts more than one million travellers to the developing world annually (1). Enterohemorrhagic E coli (EHEC) are the cause of hemolytic uremic syndrome (HUS), which has become a major foodborne threat in many parts of the developed world (2). Table 1 Categories of Diarrheagenic E. coli Category Toxins Invasion Virulence plasmid Adhesin Clinical syndrome ETEC LT, ST - Many CFA/I, CFA/II, CFA/IV, others Watery diarrhea EPEC - + 60 MDa Bundle-forming pilus Watery diarrhea of infants EHEC SLT-1, SLT-2 - 60 MDa( a ) Intimin, Fimbriae( a ) Hemorrhagic colitis, HUS EAEC EAST1( a ) ? 65 MDa( a ) AAF/I, AAF/I Watery, persistent diarrhea EIEC EIET( a ) +++ 140 MDa Ipa's(?) Watery diarrhea, dysentery DAEC ? ? ? F1845( a ) Watery diarrhea ( a )Role in pathogenesis unproven. PMID:21390758

  5. Escherichia coli in retail processed food.

    PubMed Central

    Pinegar, J. A.; Cooke, E. M.

    1985-01-01

    Four thousand two hundred and forty six samples of retail processed food were examined for the presence of Escherichia coli. Overall 12% of samples contained this organism, cakes and confectionery being more frequently contaminated (28%) than meat and meat based products (9%). Contamination was more frequent in the summer months than in the colder weather and 27% of the contaminated foods contained greater than 10(3) E. coli/g. E. coli from meat and meat based products were more commonly resistant to one or more antibiotics (14%) than were confectionery strains (1%). The significance of these findings in relation to the E. coli population of the human bowel is discussed. PMID:3894508

  6. Escherichia coli in retail processed food.

    PubMed

    Pinegar, J A; Cooke, E M

    1985-08-01

    Four thousand two hundred and forty six samples of retail processed food were examined for the presence of Escherichia coli. Overall 12% of samples contained this organism, cakes and confectionery being more frequently contaminated (28%) than meat and meat based products (9%). Contamination was more frequent in the summer months than in the colder weather and 27% of the contaminated foods contained greater than 10(3) E. coli/g. E. coli from meat and meat based products were more commonly resistant to one or more antibiotics (14%) than were confectionery strains (1%). The significance of these findings in relation to the E. coli population of the human bowel is discussed. PMID:3894508

  7. Vaginal Lactobacillus isolates inhibit uropathogenic Escherichia coli.

    PubMed

    Atassi, Fabrice; Brassart, Dominique; Grob, Philipp; Graf, Federico; Servin, Alain L

    2006-04-01

    The purpose of this study was to investigate the antibacterial activities of Lactobacillus jensenii KS119.1 and KS121.1, and Lactobacillus gasserii KS120.1 and KS124.3 strains isolated from the vaginal microflora of healthy women, against uropathogenic, diffusely adhering Afa/Dr Escherichia coli (Afa/Dr DAEC) strains IH11128 and 7372 involved in recurrent cystitis. We observed that some of the Lactobacillus isolates inhibited the growth and decreased the viability of E. coli IH11128 and 7372. In addition, we observed that adhering Lactobacillus strains inhibited adhesion of E. coli IH11128 onto HeLa cells, and inhibited internalization of E. coli IH11128 within HeLa cells. PMID:16553843

  8. Escherichia coli bacteriuria and contraceptive method.

    PubMed

    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

  9. Adhesion behaviors of Escherichia coli on hydroxyapatite.

    PubMed

    Kamitakahara, Masanobu; Takahashi, Shohei; Yokoi, Taishi; Inoue, Chihiro; Ioku, Koji

    2016-04-01

    Optimum design of support materials for microorganisms is required for the construction of bioreactors. However, the effects of support materials on microorganisms are still unclear. In this study, we investigated the adhesion behavior of Escherichia coli (E. coli) on hydroxyapatite (HA), polyurethane (PU), poly(vinyl chloride) (PVC), and carbon (Carbon) to obtain basic knowledge for the design of support materials. The total metabolic activity and number of E. coli adhering on the samples followed the order of HA ≈ Carbon>PVC>PU. On the other hand, the water contact angle of the pellet surfaces followed the order of HAcoli. The results implied that HA has a potential as a support material for microorganisms used in bioreactors. PMID:26838837

  10. FTIR nanobiosensors for Escherichia coli detection

    PubMed Central

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

    2012-01-01

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

  11. NMR Structure of Lipoprotein YxeF from Bacillus subtilis Reveals a Calycin Fold and Distant Homology with the Lipocalin Blc from Escherichia coli

    PubMed Central

    Xiao, Rong; Acton, Thomas B.; Sathyamoorthy, Bharathwaj; Dey, Fabian; Fischer, Markus; Skerra, Arne; Rost, Burkhard; Montelione, Gaetano T.; Szyperski, Thomas

    2012-01-01

    The soluble monomeric domain of lipoprotein YxeF from the Gram positive bacterium B. subtilis was selected by the Northeast Structural Genomics Consortium (NESG) as a target of a biomedical theme project focusing on the structure determination of the soluble domains of bacterial lipoproteins. The solution NMR structure of YxeF reveals a calycin fold and distant homology with the lipocalin Blc from the Gram-negative bacterium E.coli. In particular, the characteristic β-barrel, which is open to the solvent at one end, is extremely well conserved in YxeF with respect to Blc. The identification of YxeF as the first lipocalin homologue occurring in a Gram-positive bacterium suggests that lipocalins emerged before the evolutionary divergence of Gram positive and Gram negative bacteria. Since YxeF is devoid of the α-helix that packs in all lipocalins with known structure against the β-barrel to form a second hydrophobic core, we propose to introduce a new lipocalin sub-family named ‘slim lipocalins’, with YxeF and the other members of Pfam family PF11631 to which YxeF belongs constituting the first representatives. The results presented here exemplify the impact of structural genomics to enhance our understanding of biology and to generate new biological hypotheses. PMID:22693626

  12. Large plasmids of avian Escherichia coli isolates.

    PubMed

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

    1996-01-01

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

  13. Uropathogenic Escherichia coli-associated exotoxins

    PubMed Central

    Welch, Rodney A.

    2015-01-01

    Escherichia coli are a common cause of infectious disease outside of the gastrointestinal tract. Several independently evolved E. coli clades are common causes of urinary tract and blood stream infections. There is ample epidemiological and in vitro evidence that several different protein toxins common to many but not all of these strains are likely to aid the colonization and immune evasion ability of these bacteria. This review discusses our current knowledge and areas of ignorance concerning the contribution of the hemolysin, cytotoxic necrotizing factor-1 and the autotransporters, Sat, Pic and Vat to extraintestinal human disease. PMID:27337488

  14. Production of antibody fragments in Escherichia coli.

    PubMed

    Katsuda, Tomohisa; Sonoda, Hiroyuki; Kumada, Yoichi; Yamaji, Hideki

    2012-01-01

    Escherichia coli is a host widely used in the industrial production of recombinant proteins. However, the expression of heterologous proteins in E. coli often encounters the formation of inclusion bodies, which are insoluble and nonfunctional protein aggregates. For the successful production of antibody fragments, which includes single-chain variable fragments (scFvs), we describe here the modification of linker, signal, and Shine-Dalgarno (SD) sequences, the coexpression of cytoplasmic and periplasmic chaperones, and a method for fed-batch cultivation with exponential feed. PMID:22907360

  15. Uropathogenic Escherichia coli-Associated Exotoxins.

    PubMed

    Welch, Rodney A

    2016-06-01

    Escherichia coli are a common cause of infectious disease outside of the gastrointestinal tract. Several independently evolved E. coli clades are common causes of urinary tract and bloodstream infections. There is ample epidemiological and in vitro evidence that several different protein toxins common to many, but not all, of these strains are likely to aid the colonization and immune-evasion ability of these bacteria. This review discusses our current knowledge and areas of ignorance concerning the contribution of the hemolysin; cytotoxic-necrotizing factor-1; and the autotransporters, Sat, Pic, and Vat, to extraintestinal human disease. PMID:27337488

  16. Hydrogen production by recombinant Escherichia coli strains

    PubMed Central

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

    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 increasing hydrogen production are outlined and whole‐cell systems and cell‐free systems are compared. PMID:21895995

  17. Novel compound for identifying Escherichia coli.

    PubMed Central

    Watkins, W D; Rippey, S R; Clavet, C R; Kelley-Reitz, D J; Burkhardt, W

    1988-01-01

    A new chromogenic compound, 5-bromo-4-chloro-3-indoxyl-beta-D-glucuronide, was found to be useful for the rapid, specific, differential identification of Escherichia coli in the sanitary analysis of shellfish and wastewater. Of 1,025 presumptively positive colonies (blue) and 583 presumptively negative colonies (nonblue), only 1% false-negative and 5% false-positive results were found. PMID:3046494

  18. Shiga toxin-producing Escherichia coli

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In United States, it is estimated that non-O157 Shiga toxin-producing Escherichia coli (STEC) cause more illnesses than STEC O157:H7, and the majority of cases of non-O157 STEC infections is due to serogroups O26, O45, O103, O111, O121, and O145, referred to as the top six non-O157 STEC. The diseas...

  19. Draft genome sequence of Escherichia coli LCT-EC106.

    PubMed

    Li, Tianzhi; Pu, Fei; Yang, Rentao; Fang, Xiangqun; Wang, Junfeng; Guo, Yinghua; Chang, De; Su, Longxiang; Guo, Na; Jiang, Xuege; Zhao, Jiao; Liu, Changting

    2012-08-01

    Escherichia coli is a Gram-negative, rod-shaped bacterium that is commonly found in the intestine of warm-blooded organisms. Most E. coli strains are harmless, but some serotypes can cause serious food poisoning in humans. Here, we present the complete genome sequence of Escherichia coli LCT-EC106, which was isolated from CGMCC 1.2385. PMID:22843582

  20. Natural plasmid transformation in Escherichia coli.

    PubMed

    Tsen, Suh-Der; Fang, Suh-Sen; Chen, Mei-Jye; Chien, Jun-Yi; Lee, Chih-Chun; Tsen, Darwin Han-Lin

    2002-01-01

    Although Escherichia coli does not have a natural transformation process, strains of E. coli can incorporate extracellular plasmids into cytoplasm 'naturally' at low frequencies. A standard method was developed in which stationary phase cells were concentrated, mixed with plasmids, and then plated on agar plates with nutrients which allowed cells to grow. Transformed cells could then be selected by harvesting cells and plating again on selective agar plates. Competence developed in the lag phase, but disappeared during exponential growth. As more plasmids were added to the cell suspension, the number of transformants increased, eventually reaching a plateau. Supercoiled monomeric or linear concatemeric DNA could transform cells, while linear monomeric DNA could not. Plasmid transformation was not related to conjugation and was recA-independent. Most of the E. coli strains surveyed had this process. All tested plasmids, except pACYC184, could transform E. coli. Insertion of a DNA fragment containing the ampicillin resistance gene into pACYC184 made the plasmid transformable. By inserting random 20-base-pair oligonucleotides into pACYC184 and selecting for transformable plasmids, a most frequent sequence was identified. This sequence resembled the bacterial interspersed medium repetitive sequence of E. coli, suggesting the existence of a recognition sequence. We conclude that plasmid natural transformation exists in E. coli. PMID:12065899

  1. Systems Metabolic Engineering of Escherichia coli.

    PubMed

    Choi, Kyeong Rok; Shin, Jae Ho; Cho, Jae Sung; Yang, Dongsoo; Lee, Sang Yup

    2016-05-01

    Systems metabolic engineering, which recently emerged as metabolic engineering integrated with systems biology, synthetic biology, and evolutionary engineering, allows engineering of microorganisms on a systemic level for the production of valuable chemicals far beyond its native capabilities. Here, we review the strategies for systems metabolic engineering and particularly its applications in Escherichia coli. First, we cover the various tools developed for genetic manipulation in E. coli to increase the production titers of desired chemicals. Next, we detail the strategies for systems metabolic engineering in E. coli, covering the engineering of the native metabolism, the expansion of metabolism with synthetic pathways, and the process engineering aspects undertaken to achieve higher production titers of desired chemicals. Finally, we examine a couple of notable products as case studies produced in E. coli strains developed by systems metabolic engineering. The large portfolio of chemical products successfully produced by engineered E. coli listed here demonstrates the sheer capacity of what can be envisioned and achieved with respect to microbial production of chemicals. Systems metabolic engineering is no longer in its infancy; it is now widely employed and is also positioned to further embrace next-generation interdisciplinary principles and innovation for its upgrade. Systems metabolic engineering will play increasingly important roles in developing industrial strains including E. coli that are capable of efficiently producing natural and nonnatural chemicals and materials from renewable nonfood biomass. PMID:27223822

  2. Mechanisms of Emerging Diarrheagenic Escherichia coli Infection.

    PubMed

    Khan, Mohammed A.; Steiner, Ted S.

    2002-04-01

    Diarrheagenic Escherichia coli organisms are major causes of morbidity and mortality worldwide. Although most strains of E. coli are harmless commensals, a few types have emerged that are capable of disrupting the normal physiology of the human gut, producing illness ranging from watery diarrhea to fatal hemorrhagic colitis. Diarrheagenic E. coli cause infection by a variety of complex mechanisms, some of which are incompletely understood. These include adherence, elaboration of toxigenic mediators, invasion of the intestinal mucosa, and transportation of bacterial proteins into the host cells. Specific components of the host-microbial interaction that cause damage have been identified, increasing our understanding of the mechanisms of diarrhea. This article reviews some of the recent findings about the pathogenesis and infectious processes involved in three emerging pathotypes of this fascinating gram-negative bacterium. PMID:11927041

  3. Molecular mechanisms of Escherichia coli pathogenicity.

    PubMed

    Croxen, Matthew A; Finlay, B Brett

    2010-01-01

    Escherichia coli is a remarkable and diverse organism. This normally harmless commensal needs only to acquire a combination of mobile genetic elements to become a highly adapted pathogen capable of causing a range of diseases, from gastroenteritis to extraintestinal infections of the urinary tract, bloodstream and central nervous system. The worldwide burden of these diseases is staggering, with hundreds of millions of people affected annually. Eight E. coli pathovars have been well characterized, and each uses a large arsenal of virulence factors to subvert host cellular functions to potentiate its virulence. In this Review, we focus on the recent advances in our understanding of the different pathogenic mechanisms that are used by various E. coli pathovars and how they cause disease in humans. PMID:19966814

  4. Thymineless Death in Escherichia coli: Strain Specificity

    PubMed Central

    Cummings, Donald J.; Mondale, Lee

    1967-01-01

    Thymineless death of various ultraviolet (UV)-sensitive strains of Escherichia coli B and K-12 was investigated. It was found that E. coli B, Bs−12, K-12 rec-21, and possibly K-12 Lon−, all sensitive to UV, were also sensitive to thymine starvation. However, other UV-sensitive strains of E. coli were found to display the typical resistant-type kinetics of thymineless death. The correlation of these results with various other cellular processes suggested that the filament-forming ability of the bacteria might be involved in the mechanism of thymineless death. It was apparent from the present results that capacity for host-cell reactivation, recombination ability, thymine dimer excision, and probably induction of a defective prophage had little to do with determining sensitivity to thymine deprivation. Images PMID:5337772

  5. Action of sodium deoxycholate on Escherichia coli

    SciTech Connect

    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.

  6. Prodigiosin - A Multifaceted Escherichia coli Antimicrobial Agent.

    PubMed

    Danevčič, Tjaša; Borić Vezjak, Maja; Zorec, Maša; Stopar, David

    2016-01-01

    Despite a considerable interest in prodigiosin, the mechanism of its antibacterial activity is still poorly understood. In this work, Escherichia coli cells were treated with prodigiosin to determine its antimicrobial effect on bacterial physiology. The effect of prodigiosin was concentration dependent. In prodigiosin treated cells above MIC value no significant DNA damage or cytoplasmic membrane disintegration was observed. The outer membrane, however, becomes leaky. Cells had severely decreased respiration activity. In prodigiosin treated cells protein and RNA synthesis were inhibited, cells were elongated but could not divide. Pre-treatment with prodigiosin improved E. coli survival rate in media containing ampicillin, kanamycin and erythromycin but not phleomycin. The results suggest that prodigiosin acts as a bacteriostatic agent in E. coli cells. If prodigiosin was diluted, cells resumed growth. The results indicate that prodigiosin has distinct mode of antibacterial action in different bacteria. PMID:27612193

  7. Interaction between Escherichia coli and lunar fines

    NASA Technical Reports Server (NTRS)

    Johansson, K. R.

    1983-01-01

    A sample of mature lunar fines (10084.151) was solubilized to a high degree (about 17 percent) by the chelating agent salicylic acid (0.01. M). The neutralized (pH adjusted to 7.0) leachate was found to inhibit the growth of Escherichia coli (ATCC 259922) in a minimial mineral salts glucose medium; however, the inhibition was somewhat less than that caused by neutralized salicylic acid alone. The presence of lunar fines in the minimal medium was highly stimulatory to growth of E. coli following an early inhibitory response. The bacterium survived less well in the lunar leachate than in distilled water, no doubt because of the salicylate. It was concluded that the sample of lunar soil tested has nutritional value to E. coli and that certain products of fermentation helped to solubilize the lunar soil.

  8. Biodegradation of Aromatic Compounds by Escherichia coli

    PubMed Central

    Díaz, Eduardo; Ferrández, Abel; Prieto, María A.; García, José L.

    2001-01-01

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

  9. COMPARATIVE RESISTANCE OF ESCHERICHIA COLI AND ENTEROCOCCI TO CHLORINATION

    EPA Science Inventory

    Pure cultures of Escherichia coli and Enterococcus faecium were inactivated by free chlorine and monochloramine. ndigenous E. coli and enterococci in wastewater effluents were also inactivated. elective bacteriological media specifically designed for the enumeration of the target...

  10. Profiling of Escherichia coli Chromosome database.

    PubMed

    Yamazaki, Yukiko; Niki, Hironori; Kato, Jun-ichi

    2008-01-01

    The Profiling of Escherichia coli Chromosome (PEC) database (http://www.shigen.nig.ac.jp/ecoli/pec/) is designed to allow E. coli researchers to efficiently access information from functional genomics studies. The database contains two principal types of data: gene essentiality and a large collection of E. coli genetic research resources. The essentiality data are based on data compilation from published single-gene essentiality studies and on cell growth studies of large-deletion mutants. Using the circular and linear viewers for both whole genomes and the minimal genome, users can not only gain an overview of the genome structure but also retrieve information on contigs, gene products, mutants, deletions, and so forth. In particular, genome-wide exhaustive mutants are an essential resource for studying E. coli gene functions. Although the genomic database was constructed independently from the genetic resources database, users may seamlessly access both types of data. In addition to these data, the PEC database also provides a summary of homologous genes of other bacterial genomes and of protein structure information, with a comprehensive interface. The PEC is thus a convenient and useful platform for contemporary E. coli researchers. PMID:18392982

  11. Logarithmic Sensing in Escherichia coli Bacterial Chemotaxis

    PubMed Central

    Kalinin, Yevgeniy V.; Jiang, Lili; Tu, Yuhai; Wu, Mingming

    2009-01-01

    We studied the response of swimming Escherichia coli (E. coli) bacteria in a comprehensive set of well-controlled chemical concentration gradients using a newly developed microfluidic device and cell tracking imaging technique. In parallel, we carried out a multi-scale theoretical modeling of bacterial chemotaxis taking into account the relevant internal signaling pathway dynamics, and predicted bacterial chemotactic responses at the cellular level. By measuring the E. coli cell density profiles across the microfluidic channel at various spatial gradients of ligand concentration grad[L] and the average ligand concentration [L]¯near the peak chemotactic response region, we demonstrated unambiguously in both experiments and model simulation that the mean chemotactic drift velocity of E. coli cells increased monotonically with grad [L]/[L]¯ or ∼grad(log[L])—that is E. coli cells sense the spatial gradient of the logarithmic ligand concentration. The exact range of the log-sensing regime was determined. The agreements between the experiments and the multi-scale model simulation verify the validity of the theoretical model, and revealed that the key microscopic mechanism for logarithmic sensing in bacterial chemotaxis is the adaptation kinetics, in contrast to explanations based directly on ligand occupancy. PMID:19289068

  12. Protein secretion controlled by a synthetic gene in Escherichia coli.

    PubMed

    Blanchin-Roland, S; Masson, J M

    1989-03-01

    The inability of Escherichia coli to secrete proteins in growth medium is one of the major drawbacks in its use in genetic engineering. A synthetic gene, homologous to the one coding for the kil peptide of pColE1, was made and cloned under the control of the lac promoter, in order to obtain the inducible secretion of homologous or heterologous proteins by E. coli. The efficiency of this synthetic gene to promote secretion was assayed by analysing the production and secretion of two proteins, the R-TEM1 beta-lactamase, and the alpha-amylase from Bacillus licheniformis. This latter protein was expressed in E. coli from its gene either on the same plasmid as the kil gene or on a different plasmid. The primary effect of the induction of the kil gene is the overproduction of the secreted proteins. When expressed at a high level, the kil gene promotes the overproduction of all periplasmic proteins and the total secretion in the culture medium of both the beta-lactamase or the alpha-amylase. This secretion is semi-selective for most periplasmic proteins are not secreted. The kil peptide induces the secretion of homologous or heterologous proteins in two steps, first acting on the cytoplasmic membrane, then permeabilizing the outer membrane. This system, which is now being assayed at the fermentor scale, is the first example of using a synthetic gene to engineer a new property into a bacterial strain. PMID:2652141

  13. ELECTROPHORETIC MOBILITIES OF ESCHERICHIA COLI 0157:H7 AND WILD-TYPE ESCHERICHIA COLI STRAINS

    EPA Science Inventory

    The electrophoretic mobility (EPM) of a number of human-virulent and "wild-type" Escherichia coli strains in phosphate buffered water was measured. The impact of pH, ionic strength, cation type (valence) and concentration, and bacterial strain on the EPM was investigated. Resul...

  14. Cyanide degradation by an Escherichia coli strain.

    PubMed

    Figueira, M M; Ciminelli, V S; de Andrade, M C; Linardi, V R

    1996-05-01

    Chemical formation of a glucose-cyanide complex was necessary for metabolic degradation of cyanide at concentrations up to 50.0 mg/L by a strain of Escherichia coli isolated from gold extraction circuit liquids. Ammonia accumulating during the culture log phase as the sole nitrogen by-product was further utilized for bacterial growth. Washed (intact) cells, harvested at different periods of bacterial growth on cyanide, consumed oxygen in presence of cyanide. These findings suggest that metabolism of cyanide involved a dioxygenase enzyme that converted cyanide directly to ammonia, without the formation of cyanate. PMID:8640610

  15. Escherichia coli growth under modeled reduced gravity

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

    Bacteria exhibit varying responses to modeled reduced gravity that can be simulated by clino-rotation. When Escherichia coli was subjected to different rotation speeds during clino-rotation, significant differences between modeled reduced gravity and normal gravity controls were observed only at higher speeds (30-50 rpm). There was no apparent affect of removing samples on the results obtained. When E. coli was grown in minimal medium (at 40 rpm), cell size was not affected by modeled reduced gravity and there were few differences in cell numbers. However, in higher nutrient conditions (i.e., dilute nutrient broth), total cell numbers were higher and cells were smaller under reduced gravity compared to normal gravity controls. Overall, the responses to modeled reduced gravity varied with nutrient conditions; larger surface to volume ratios may help compensate for the zone of nutrient depletion around the cells under modeled reduced gravity.

  16. Enterotoxigenic Escherichia coli: Orchestrated host engagement.

    PubMed

    Fleckenstein, James M; Munson, George M; Rasko, David A

    2013-01-01

    The enterotoxigenic Escherichia coli are a pervasive cause of serious diarrheal illness in developing countries. Presently, there is no vaccine to prevent these infections, and many features of the basic pathogenesis of these organisms remain poorly understood. Until very recently most pathogenesis studies had focused almost exclusively on a small subset of known "classical" virulence genes, namely fimbrial colonization factors and the heat-labile (LT) and heat stable (ST) enterotoxins. However, recent investigations of pathogen-host interactions reveal a surprisingly complex and intricately orchestrated engagement involving the interplay of classical and "novel" virulence genes, as well as participation of genes highly conserved in the E. coli species. These studies may inform further rational approaches to vaccine development for these important pathogens. PMID:23892244

  17. Engineering the Escherichia coli Fermentative Metabolism

    NASA Astrophysics Data System (ADS)

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

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

  18. Gas signatures from Escherichia coli and Escherichia coli-inoculated human whole blood

    PubMed Central

    2013-01-01

    Background The gaseous headspace above naïve Escherichia Coli (E. coli) cultures and whole human blood inoculated with E. coli were collected and analyzed for the presence of trace gases that may have the potential to be used as novel, non-invasive markers of infectious disease. Methods The naïve E. coli culture, LB broth, and human whole blood or E. coli inoculated whole blood were incubated in hermetically sealable glass bioreactors at 37°C for 24 hrs. LB broth and whole human blood were used as controls for background volatile organic compounds (VOCs). The headspace gases were collected after incubation and analyzed using a gas chromatographic system with multiple column/detector combinations. Results Six VOCs were observed to be produced by E. coli-infected whole blood while there existed nearly zero to relatively negligible amounts of these gases in the whole blood alone, LB broth, or E. coli-inoculated LB broth. These VOCs included dimethyl sulfide (DMS), carbon disulfide (CS2), ethanol, acetaldehyde, methyl butanoate, and an unidentified gas S. In contrast, there were several VOCs significantly elevated in the headspace above the E. coli in LB broth, but not present in the E. coli/blood mixture. These VOCs included dimethyl disulfide (DMDS), dimethyl trisulfide (DMTS), methyl propanoate, 1-propanol, methylcyclohexane, and unidentified gases R2 and Q. Conclusions This study demonstrates 1) that cultivated E. coli in LB broth produce distinct gas profiles, 2) for the first time, the ability to modify E. coli-specific gas profiles by the addition of whole human blood, and 3) that E. coli-human whole blood interactions present different gas emission profiles that have the potential to be used as non-invasive volatile biomarkers of E. coli infection. PMID:23842518

  19. Escherichia coli as a bioreporter in ecotoxicology.

    PubMed

    Robbens, Johan; Dardenne, Freddy; Devriese, Lisa; De Coen, Wim; Blust, Ronny

    2010-11-01

    Ecotoxicological assessment relies to a large extent on the information gathered with surrogate species and the extrapolation of test results across species and different levels of biological organisation. Bacteria have long been used as a bioreporter for genotoxic testing and general toxicity. Today, it is clear that bacteria have the potential for screening of other toxicological endpoints. Escherichia coli has been studied for years; in-depth knowledge of its biochemistry and genetics makes it the most proficient prokaryote for the development of new toxicological assays. Several assays have been designed with E. coli as a bioreporter, and the recent trend to develop novel, better advanced reporters makes bioreporter development one of the most dynamic in ecotoxicology. Based on in-depth knowledge of E. coli, new assays are being developed or existing ones redesigned, thanks to the availability of new reporter genes and new or improved substrates. The technological evolution towards easier and more sensitive detection of different gene products is another important aspect. Often, this requires the redesign of the bacterium to make it compatible with the novel measuring tests. Recent advances in surface chemistry and nanoelectronics open the perspective for advanced reporter based on novel measuring platforms and with an online potential. In this article, we will discuss the use of E. coli-based bioreporters in ecotoxicological applications as well as some innovative sensors awaited for the future. PMID:20803141

  20. Transport proteins promoting Escherichia coli pathogenesis

    PubMed Central

    Tang, Fengyi; Saier, Milton H.

    2014-01-01

    Escherichia coli is a genetically diverse species infecting hundreds of millions of people worldwide annually. We examined seven well-characterized E. coli pathogens causing urinary tract infections, gastroenteritis, pyelonephritis and haemorrhagic colitis. Their transport proteins were identified and compared with each other and a non-pathogenic E. coli K12 strain to identify transport proteins related to pathogenesis. Each pathogen possesses a unique set of protein secretion systems for export to the cell surface or for injecting effector proteins into host cells. Pathogens have increased numbers of iron siderophore receptors and ABC iron uptake transporters, but the numbers and types of low-affinity secondary iron carriers were uniform in all strains. The presence of outer membrane iron complex receptors and high-affinity ABC iron uptake systems correlated, suggesting co-evolution. Each pathovar encodes a different set of pore-forming toxins and virulence-related outer membrane proteins lacking in K12. Intracellular pathogens proved to have a characteristically distinctive set of nutrient uptake porters, different from those of extracellular pathogens. The results presented in this report provide information about transport systems relevant to various types of E. coli pathogenesis that can be exploited in future basic and applied studies. PMID:24747185

  1. Pattern Formation of Bacterial Colonies by Escherichia coli

    NASA Astrophysics Data System (ADS)

    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.

  2. Discrepancies in the enumeration of Escherichia coli.

    PubMed

    Ray, B; Speck, M L

    1973-04-01

    Stationary-phase cells of Escherichia coli were enumerated by the pour plate method on Trypticase soy agar containing 0.3% yeast extract (TSYA), violet red-bile agar, and desoxycholate-lactose agar, and by the most-probable-number method in Brilliant Green-bile broth and lauryl sulfate broth. Maximum counts were assumed to be those on TSYA. In general, numbers detected were lower with the selective solid media and higher with the selective liquid media. Inhibitory effects, especially on selective solid media varied with the strains of E. coli. The lower detection on selective solid media was partly due to the stress induced in some cells by the temperature of the melted media used in the pour plate method. These cells apparently failed to repair and form colonies in the selective media. Improved detection on the selective solid media was achieved by using 1% nonfat milk solids, 1% peptone, or 1% MgSO(4).7H(2)O in the dilution blanks. Higher detection on selective agar media was effected by surface plating or by surface-overlay plating of the cells. The surface-overlay method appeared to be superior for the direct enumeration of E. coli in foods. PMID:4572980

  3. Role of Escherichia coli in Biofuel Production.

    PubMed

    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

  4. [Population genomic researches of Escherichia coli].

    PubMed

    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

  5. Escherichia coli biofilm: development and therapeutic strategies.

    PubMed

    Sharma, G; Sharma, S; Sharma, P; Chandola, D; Dang, S; Gupta, S; Gabrani, R

    2016-08-01

    Escherichia coli biofilm consists of a bacterial colony embedded in a matrix of extracellular polymeric substances (EPS) which protects the microbes from adverse environmental conditions and results in infection. Besides being the major causative agent for recurrent urinary tract infections, E. coli biofilm is also responsible for indwelling medical device-related infectivity. The cell-to-cell communication within the biofilm occurs due to quorum sensors that can modulate the key biochemical players enabling the bacteria to proliferate and intensify the resultant infections. The diversity in structural components of biofilm gets compounded due to the development of antibiotic resistance, hampering its eradication. Conventionally used antimicrobial agents have a restricted range of cellular targets and limited efficacy on biofilms. This emphasizes the need to explore the alternate therapeuticals like anti-adhesion compounds, phytochemicals, nanomaterials for effective drug delivery to restrict the growth of biofilm. The current review focuses on various aspects of E. coli biofilm development and the possible therapeutic approaches for prevention and treatment of biofilm-related infections. PMID:26811181

  6. Role of Escherichia coli in Biofuel Production

    PubMed Central

    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

  7. Non-O157 Shiga toxin-producing Escherichia coli

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Shiga toxin-producing Escherichia coli (STEC), also known as verocytotoxin-producing E. coli, are important food-borne pathogens responsible for outbreaks of hemorrhagic colitis (HC) and hemolytic uremic syndrome (HUS). STEC that cause HC and HUS are also referred to as enterohemorrhagic E. coli (E...

  8. WGS accurately predicts antimicrobial resistance in Escherichia coli

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Objectives: To determine the effectiveness of whole-genome sequencing (WGS) in identifying resistance genotypes of multidrug-resistant Escherichia coli (E. coli) and whether these correlate with observed phenotypes. Methods: Seventy-six E. coli strains were isolated from farm cattle and measured f...

  9. Virulence Gene Regulation in Escherichia coli.

    PubMed

    Mellies, Jay L; Barron, Alex M S

    2006-01-01

    Escherichia colicauses three types of illnesses in humans: diarrhea, urinary tract infections, and meningitis in newborns. The acquisition of virulence-associated genes and the ability to properly regulate these, often horizontally transferred, loci distinguishes pathogens from the normally harmless commensal E. coli found within the human intestine. This review addresses our current understanding of virulence gene regulation in several important diarrhea-causing pathotypes, including enteropathogenic, enterohemorrhagic,enterotoxigenic, and enteroaggregativeE. coli-EPEC, EHEC, ETEC and EAEC, respectively. The intensely studied regulatory circuitry controlling virulence of uropathogenicE. coli, or UPEC, is also reviewed, as is that of MNEC, a common cause of meningitis in neonates. Specific topics covered include the regulation of initial attachment events necessary for infection, environmental cues affecting virulence gene expression, control of attaching and effacing lesionformation, and control of effector molecule expression and secretion via the type III secretion systems by EPEC and EHEC. How phage control virulence and the expression of the Stx toxins of EHEC, phase variation, quorum sensing, and posttranscriptional regulation of virulence determinants are also addressed. A number of important virulence regulators are described, including the AraC-like molecules PerA of EPEC, CfaR and Rns of ETEC, and AggR of EAEC;the Ler protein of EPEC and EHEC;RfaH of UPEC;and the H-NS molecule that acts to silence gene expression. The regulatory circuitry controlling virulence of these greatly varied E. colipathotypes is complex, but common themes offerinsight into the signals and regulators necessary forE. coli disease progression. PMID:26443571

  10. Efficient production of indigoidine in Escherichia coli.

    PubMed

    Xu, Fuchao; Gage, David; Zhan, Jixun

    2015-08-01

    Indigoidine is a bacterial natural product with antioxidant and antimicrobial activities. Its bright blue color resembles the industrial dye indigo, thus representing a new natural blue dye that may find uses in industry. In our previous study, an indigoidine synthetase Sc-IndC and an associated helper protein Sc-IndB were identified from Streptomyces chromofuscus ATCC 49982 and successfully expressed in Escherichia coli BAP1 to produce the blue pigment at 3.93 g/l. To further improve the production of indigoidine, in this work, the direct biosynthetic precursor L-glutamine was fed into the fermentation broth of the engineered E. coli strain harboring Sc-IndC and Sc-IndB. The highest titer of indigoidine reached 8.81 ± 0.21 g/l at 1.46 g/l L-glutamine. Given the relatively high price of L-glutamine, a metabolic engineering technique was used to directly enhance the in situ supply of this precursor. A glutamine synthetase gene (glnA) was amplified from E. coli and co-expressed with Sc-indC and Sc-indB in E. coli BAP1, leading to the production of indigoidine at 5.75 ± 0.09 g/l. Because a nitrogen source is required for amino acid biosynthesis, we then tested the effect of different nitrogen-containing salts on the supply of L-glutamine and subsequent indigoidine production. Among the four tested salts including (NH4)2SO4, NH4Cl, (NH4)2HPO4 and KNO3, (NH4)2HPO4 showed the best effect on improving the titer of indigoidine. Different concentrations of (NH4)2HPO4 were added to the fermentation broths of E. coli BAP1/Sc-IndC+Sc-IndB+GlnA, and the titer reached the highest (7.08 ± 0.11 g/l) at 2.5 mM (NH4)2HPO4. This work provides two efficient methods for the production of this promising blue pigment in E. coli. PMID:26109508

  11. Selective translation during stress in Escherichia coli

    PubMed Central

    Moll, Isabella; Engelberg-Kulka, Hanna

    2016-01-01

    The bacterial stress response, a strategy to cope with environmental changes, is generally known to operate on the transcriptional level. Here, we discuss a novel paradigm for stress adaptation at the post-transcriptional level, based on the recent discovery of a stress-induced modified form of the translation machinery in Escherichia coli that is generated by MazF, the toxin component of the toxin–antitoxin (TA) module mazEF. Under stress, the induced endoribonuclease MazF removes the 3′-terminal 43 nucleotides of the 16S rRNA of ribosomes and, concomitantly, the 5′-untranslated regions (UTRs) of specific transcripts. This elegant mechanism enables selective translation due to the complementary effect of MazF on ribosomes and mRNAs, and also represents the first example of functional ribosome heterogeneity based on rRNA alteration. PMID:22939840

  12. Escherichia coli photoreactivating enzyme: purification and properties

    SciTech Connect

    Snapka, R.M.; Sutherland, B.M.

    1980-01-01

    Researchers have purified large quantities of Escherichia coli photoreactivating enzyme to apparent homogeneity and have studied its physical and chemical properties. The enzyme has a molecular weight of 36,800 and a S/sub 20,w//sup 0/ of 3.72 S. Amino acid analysis revealed an apparent absence of tryptophan, a low content of aromatic residues, and the presence of no unusual amino acids. The N terminus is arginine. The purified enzyme contained up to 13% carbohydrate by weight. The carbohydrate was composed of mannose, galactose, glucose, and N-acetylglucosamine. The enzyme is also associated with RNA containing uracil, adenine, guanine, and cytosine with no unusual bases detected.

  13. Genetic Analysis of an Escherichia coli Syndrome

    PubMed Central

    Lennette, Evelyne T.; Apirion, David

    1971-01-01

    A mutant strain of Escherichia coli that fails to recover from prolonged (72 hr) starvation also fails to grow at 43 C. Extracts of this mutant strain show an increased ribonuclease II activity as compared to extracts of the parental strain, and stable ribonucleic acid is degraded to a larger extent in this strain during starvation. Ts+ transductants and revertants were tested for all the above-mentioned phenotypes. All the Ts+ transductants and revertants tested behaved like the Ts+ parental strain, which suggests that all the observed phenotypes are caused by a single sts (starvation-temperature sensitivity) mutation. The reversion rate from sts− to sts+ is rather low but is within the range of reversion rates for other single-site mutations. Three-point transduction crosses located this sts mutation between the ilv and rbs genes. The properties of sts+/sts− merozygotes suggested that the Ts− phenotype of this mutation is recessive. PMID:4945197

  14. Phosphoglucomutase Mutants of Escherichia coli K-12

    PubMed Central

    Adhya, Sankar; Schwartz, Maxime

    1971-01-01

    Bacteria with strongly depressed phosphoglucomutase (EC 2.7.5.1) activity are found among the mutants of Escherichia coli which, when grown on maltose, accumulate sufficient amylose to be detectable by iodine staining. These pgm mutants grow poorly on galactose but also accumulate amylose on this carbon source. Growth on lactose does not produce high amylose but, instead, results in the induction of the enzymes of maltose metabolism, presumably by accumulation of maltose. These facts suggest that the catabolism of glucose-1-phosphate is strongly depressed in pgm mutants, although not completely abolished. Anabolism of glucose-1-phosphate is also strongly depressed, since amino acid- or glucose-grown pgm mutants are sensitive to phage C21, indicating a deficiency in the biosynthesis of uridine diphosphoglucose or uridine diphosphogalactose, or both. All pgm mutations isolated map at about 16 min on the genetic map, between purE and the gal operon. PMID:4942754

  15. Structure of common pili from Escherichia coli.

    PubMed Central

    McMichael, J C; Ou, J T

    1979-01-01

    Several important properties of the common pili from Escherichia coli are discussed. These pili were resistant to the gentle Folin-Ciocalteau reagent methods for protein detection and were not readily solubilized by sodium dodecyl sulfate. They were found to contain a reducing sugar but not peptidoglycan. The pilin had multiple conformations in sodium dodecyl sulfate solution, and the appearance of multiple bands on sodium dodecyl sulfate gels did not necessarily indicate heterogeneity of the preparation. The ilus subunit was found to be a different protein than outer membrane III, which has the same apparent molecular weight. In addition, we conformed the results of Brinton (Trans. N.Y. Acad. Sci 27:1003-1054, 1965): that there is a dramatic change in the properties of pili after they are heated at pH values below 2. Images PMID:37233

  16. Novel antigens for enterotoxigenic Escherichia coli vaccines.

    PubMed

    Fleckenstein, James; Sheikh, Alaullah; Qadri, Firdausi

    2014-05-01

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

  17. Oxygen sensitivity of an Escherichia coli mutant.

    PubMed

    Adler, H; Mural, R; Suttle, B

    1992-04-01

    Genetic evidence indicates that Oxys-6, an oxygen-sensitive mutant of Escherichia coli AB1157, is defective in the region of the hemB locus. Oxys-6 is capable of growth under aerobic conditions only if cultures are initiated at low-inoculum levels. Aerobic liquid cultures are limited to a cell density of 10(7) cells per ml by the accumulation of a metabolically produced, low-molecular-weight, heat-stable material in complex organic media. Both Oxys-6 and AB1157 cells produce the material, but only aerobic cultures of the mutant are inhibited by it. The material is produced by both intact cells and cell extracts in complex media. This reaction also occurs when the amino acid L-lysine is substituted for complex media. PMID:1551829

  18. Oxygen sensitivity of an Escherichia coli mutant.

    PubMed Central

    Adler, H; Mural, R; Suttle, B

    1992-01-01

    Genetic evidence indicates that Oxys-6, an oxygen-sensitive mutant of Escherichia coli AB1157, is defective in the region of the hemB locus. Oxys-6 is capable of growth under aerobic conditions only if cultures are initiated at low-inoculum levels. Aerobic liquid cultures are limited to a cell density of 10(7) cells per ml by the accumulation of a metabolically produced, low-molecular-weight, heat-stable material in complex organic media. Both Oxys-6 and AB1157 cells produce the material, but only aerobic cultures of the mutant are inhibited by it. The material is produced by both intact cells and cell extracts in complex media. This reaction also occurs when the amino acid L-lysine is substituted for complex media. Images PMID:1551829

  19. Direct Upstream Motility in Escherichia coli

    PubMed Central

    Kaya, Tolga; Koser, Hur

    2012-01-01

    We provide an experimental demonstration of positive rheotaxis (rapid and continuous upstream motility) in wild-type Escherichia coli freely swimming over a surface. This hydrodynamic phenomenon is dominant below a critical shear rate and robust against Brownian motion and cell tumbling. We deduce that individual bacteria entering a flow system can rapidly migrate upstream (>20 μm/s) much faster than a gradually advancing biofilm. Given a bacterial population with a distribution of sizes and swim speeds, local shear rate near the surface determines the dominant hydrodynamic mode for motility, i.e., circular or random trajectories for low shear rates, positive rheotaxis for moderate flow, and sideways swimming at higher shear rates. Faster swimmers can move upstream more rapidly and at higher shear rates, as expected. Interestingly, we also find on average that both swim speed and upstream motility are independent of cell aspect ratio. PMID:22500751

  20. Glucose-lactose diauxie in Escherichia coli.

    PubMed

    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

  1. Genes under positive selection in Escherichia coli

    PubMed Central

    Petersen, Lise; Bollback, Jonathan P.; Dimmic, Matt; Hubisz, Melissa; Nielsen, Rasmus

    2007-01-01

    We used a comparative genomics approach to identify genes that are under positive selection in six strains of Escherichia coli and Shigella flexneri, including five strains that are human pathogens. We find that positive selection targets a wide range of different functions in the E. coli genome, including cell surface proteins such as beta barrel porins, presumably because of the involvement of these genes in evolutionary arms races with other bacteria, phages, and/or the host immune system. Structural mapping of positively selected sites on trans-membrane beta barrel porins reveals that the residues under positive selection occur almost exclusively in the extracellular region of the proteins that are enriched with sites known to be targets of phages, colicins, or the host immune system. More surprisingly, we also find a number of other categories of genes that show very strong evidence for positive selection, such as the enigmatic rhs elements and transposases. Based on structural evidence, we hypothesize that the selection acting on transposases is related to the genomic conflict between transposable elements and the host genome. PMID:17675366

  2. Independence of replisomes in Escherichia coli chromosomalreplication

    SciTech Connect

    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.

  3. Thiol-sensitive genes of Escherichia coli.

    PubMed Central

    Javor, G T

    1989-01-01

    The effect of 1-thioglycerol on the expression of genes of Escherichia coli was investigated. Pulse-labeled proteins from aerobically growing, 1-thioglycerol-treated E. coli were separated by two-dimensional gel electrophoresis, and their radioactivities were compared with those of identical proteins from nontreated cells. The first 10 min of exposure to thiol stimulated the synthesis of 10% of the observed proteins and inhibited the production of 16% of the proteins. After 30 min of growth with thiol, the synthesis of 44% of the observed proteins was inhibited and synthesis of 18% of the proteins was stimulated. In general, the expression of genes of carbohydrate metabolism, amino acid metabolism, and protein biosynthesis were inhibited, while nucleic acid synthetic and repair gene expressions showed mixed responses. Synthesis of transport proteins was not affected. Transient stimulation of oxidative-stress proteins and sustained stimulation of the expressions of trxB, ompA, and ompB genes and those of several unidentified gene products were also observed. Whether these complex responses merely reflect adjustments by cellular subsystems to a suddenly reducing environment or whether they are manifestations of a reductive-stress regulon will have to await genetic analysis of this phenomenon. Images PMID:2676982

  4. gltBDF operon of Escherichia coli.

    PubMed Central

    Castaño, I; Bastarrachea, F; Covarrubias, A A

    1988-01-01

    A 2.0-kilobase DNA fragment carrying antibiotic resistance markers was inserted into the gltB gene of Escherichia coli previously cloned in a multicopy plasmid. Replacement of the chromosomal gltB+ gene by the gltB225::omega mutation led to cells unable to synthesize glutamate synthase, utilize growth rate-limiting nitrogen sources, or derepress their glutamine synthetase. The existence of a gltBDF operon encoding the large (gltB) and small (gltD) subunits of glutamate synthase and a regulatory peptide (gltF) at 69 min of the E. coli linkage map was deduced from complementation analysis. A plasmid carrying the entire gltB+D+F+ operon complemented cells for all three of the mutant phenotypes associated with the polar gltB225::omega mutation in the chromosome. By contrast, plasmids carrying gltB+ only complemented cells for glutamate synthase activity. A major tricistronic mRNA molecule was detected from Northern (RNA blot) DNA-RNA hybridization experiments with DNA probes containing single genes of the operon. A 30,200-dalton polypeptide was identified as the gltF product, the lack of which was responsible for the inability of cells to use nitrogen-limiting sources associated with gltB225::omega. Images PMID:2448295

  5. The extracellular RNA complement of Escherichia coli

    PubMed Central

    Ghosal, Anubrata; Upadhyaya, Bimal Babu; Fritz, Joëlle V; Heintz-Buschart, Anna; Desai, Mahesh S; Yusuf, Dilmurat; Huang, David; Baumuratov, Aidos; Wang, Kai; Galas, David; Wilmes, Paul

    2015-01-01

    The secretion of biomolecules into the extracellular milieu is a common and well-conserved phenomenon in biology. In bacteria, secreted biomolecules are not only involved in intra-species communication but they also play roles in inter-kingdom exchanges and pathogenicity. To date, released products, such as small molecules, DNA, peptides, and proteins, have been well studied in bacteria. However, the bacterial extracellular RNA complement has so far not been comprehensively characterized. Here, we have analyzed, using a combination of physical characterization and high-throughput sequencing, the extracellular RNA complement of both outer membrane vesicle (OMV)-associated and OMV-free RNA of the enteric Gram-negative model bacterium Escherichia coli K-12 substrain MG1655 and have compared it to its intracellular RNA complement. Our results demonstrate that a large part of the extracellular RNA complement is in the size range between 15 and 40 nucleotides and is derived from specific intracellular RNAs. Furthermore, RNA is associated with OMVs and the relative abundances of RNA biotypes in the intracellular, OMV and OMV-free fractions are distinct. Apart from rRNA fragments, a significant portion of the extracellular RNA complement is composed of specific cleavage products of functionally important structural noncoding RNAs, including tRNAs, 4.5S RNA, 6S RNA, and tmRNA. In addition, the extracellular RNA pool includes RNA biotypes from cryptic prophages, intergenic, and coding regions, of which some are so far uncharacterised, for example, transcripts mapping to the fimA-fimL and ves-spy intergenic regions. Our study provides the first detailed characterization of the extracellular RNA complement of the enteric model bacterium E. coli. Analogous to findings in eukaryotes, our results suggest the selective export of specific RNA biotypes by E. coli, which in turn indicates a potential role for extracellular bacterial RNAs in intercellular communication. PMID:25611733

  6. Escherichia coli mutants deficient in exonuclease VII.

    PubMed Central

    Chase, J W; Richardson, C C

    1977-01-01

    Mutants of Escherichia coli having reduced levels of exonuclease VII activity have been isolated by a mass screening procedure. Nine mutants, five of which are known to be of independent origin, were obtained and designated xse. The defects in these strains lie at two or more loci. One of these loci, xseA, lies in the interval between purG and purC; it is 93 to 97% co-transducible with guaA. The order of the genes in this region is purG-xseA guaA,B-purC. The available data do not allow xseA to be ordered with respect to guaA,B. Exonuclease VII purified from E. coli KLC3 xseA3 is more heat labile than exonuclease VII purified from the parent, E. coli PA610 xse+. Therefore, xseA is the structural gene for exonuclease VII. Mutants with defects in the xseA gene show increased sensitivity to nalidixic acid and have an abnormally high frequency of recombination (hyper-Rec phenotype) as measured by the procedure of Konrad and Lehlman (1974). The hyper-Rec character of xseA strains is approximately one-half that of the polAex1 mutant defective in the 5' leads to 3' hydrolytic activity of deoxyribonucleic acid polymerase I. The double mutant, polAex1 xseA7, is twice as hyper-Rec as the polAex1 mutant alone. The xseA- strains are slightly more sensitive to ultraviolet irradiation than the parent strain. Bacteriophages T7, fd, and lambdared grow normally in xseA- strains. Images PMID:320198

  7. Biochemical properties and yields of diverse bacterial laccase-like multicopper oxidases expressed in Escherichia coli.

    PubMed

    Ihssen, Julian; Reiss, Renate; Luchsinger, Ronny; Thöny-Meyer, Linda; Richter, Michael

    2015-01-01

    Laccases are multi-copper oxidases that oxidize a broad range of substrates at the expense of molecular oxygen, without any need for co-factor regeneration. These enzymes bear high potential for the sustainable synthesis of fine chemicals and the modification of (bio)polymers. Here we describe cloning and expression of five novel bacterial laccase-like multi copper oxidases (LMCOs) of diverse origin which were identified by homology searches in online databases. Activity yields under different expression conditions and temperature stabilities were compared to three previously described enzymes from Bacillus subtilis, Bacillus pumilus and Bacillus clausii. In almost all cases, a switch to oxygen-limited growth conditions after induction increased volumetric activity considerably. For proteins with predicted signal peptides for secretion, recombinant expression with and without signal sequence was investigated. Bacillus CotA-type LMCOs outperformed enzymes from Streptomyces and Gram-negative bacteria with respect to activity yields in Escherichia coli and application relevant biochemical properties. The novel Bacillus coagulans LMCO combined high activity yields in E. coli with unprecedented activity at strong alkaline pH and high storage stability, making it a promising candidate for further development. PMID:26068013

  8. Biochemical properties and yields of diverse bacterial laccase-like multicopper oxidases expressed in Escherichia coli

    PubMed Central

    Ihssen, Julian; Reiss, Renate; Luchsinger, Ronny; Thöny-Meyer, Linda; Richter, Michael

    2015-01-01

    Laccases are multi-copper oxidases that oxidize a broad range of substrates at the expense of molecular oxygen, without any need for co-factor regeneration. These enzymes bear high potential for the sustainable synthesis of fine chemicals and the modification of (bio)polymers. Here we describe cloning and expression of five novel bacterial laccase-like multi copper oxidases (LMCOs) of diverse origin which were identified by homology searches in online databases. Activity yields under different expression conditions and temperature stabilities were compared to three previously described enzymes from Bacillus subtilis, Bacillus pumilus and Bacillus clausii. In almost all cases, a switch to oxygen-limited growth conditions after induction increased volumetric activity considerably. For proteins with predicted signal peptides for secretion, recombinant expression with and without signal sequence was investigated. Bacillus CotA-type LMCOs outperformed enzymes from Streptomyces and Gram-negative bacteria with respect to activity yields in Escherichia coli and application relevant biochemical properties. The novel Bacillus coagulans LMCO combined high activity yields in E. coli with unprecedented activity at strong alkaline pH and high storage stability, making it a promising candidate for further development. PMID:26068013

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

    PubMed Central

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

    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 host-specificity. Finally, we highlight the fact that dietary components frequently found in industrialized countries may enhance AIEC colonization in the gut, which merits further investigation and the implementation of preventative measures. PMID:25133024

  10. Escherichia coli survival in waters: temperature dependence.

    PubMed

    Blaustein, R A; Pachepsky, Y; Hill, R L; Shelton, D R; Whelan, G

    2013-02-01

    Knowing the survival rates of water-borne Escherichia coli is important in evaluating microbial contamination and making appropriate management decisions. E. coli survival rates are dependent on temperature, a dependency that is routinely expressed using an analogue of the Q₁₀ model. This suggestion was made 34 years ago based on 20 survival curves taken from published literature, but has not been revisited since then. The objective of this study was to re-evaluate the accuracy of the Q₁₀ equation, utilizing data accumulated since 1978. We assembled a database of 450 E. coli survival datasets from 70 peer-reviewed papers. We then focused on the 170 curves taken from experiments that were performed in the laboratory under dark conditions to exclude the effects of sunlight and other field factors that could cause additional variability in results. All datasets were tabulated dependencies "log concentration vs. time." There were three major patterns of inactivation: about half of the datasets had a section of fast log-linear inactivation followed by a section of slow log-linear inactivation; about a quarter of the datasets had a lag period followed by log-linear inactivation; and the remaining quarter were approximately linear throughout. First-order inactivation rate constants were calculated from the linear sections of all survival curves and the data grouped by water sources, including waters of agricultural origin, pristine water sources, groundwater and wells, lakes and reservoirs, rivers and streams, estuaries and seawater, and wastewater. Dependency of E. coli inactivation rates on temperature varied among the water sources. There was a significant difference in inactivation rate values at the reference temperature between rivers and agricultural waters, wastewaters and agricultural waters, rivers and lakes, and wastewater and lakes. At specific sites, the Q₁₀ equation was more accurate in rivers and coastal waters than in lakes making the value of

  11. TRIMETHOPRIM-SULFAMETHOXAZOLE RESISTANCE IN SEWAGE ISOLATES OF ESCHERICHIA COLI

    EPA Science Inventory

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

  12. The Escherichia coli Peripheral Inner Membrane Proteome*

    PubMed Central

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

    2013-01-01

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

  13. The N-degradome of Escherichia coli

    PubMed Central

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

    2013-01-01

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

  14. Biocontrol of Escherichia coli O157

    PubMed Central

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

    2013-01-01

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

  15. Routes for fructose utilization by Escherichia coli.

    PubMed

    Kornberg, H L

    2001-07-01

    There are three main routes for the utilization of fructose by Escherichia coli. One (Route A) predominates in the growth of wild-type strains. It involves the functioning of the phosphoenolpyruvate:glycose phosphotransferase system (PTS) and a fructose operon, mapping at min. 48.7, containing genes for a membrane-spanning protein (fruA), a 1-phosphofructose kinase (fruK) and a diphosphoryl transfer protein (fruB), under negative regulation by a fruR gene mapping at min. 1.9. A second route (Route B) also involves the PTS and membrane-spanning proteins that recognize a variety of sugars possessing the 3,4,5-D-arabino-hexoseconfiguration but with primary specificity for mannose(manXYZ), mannitol (mtlA) and glucitol (gutA) and which, if over-produced, can transport also fructose. A third route (Route C), functioning in mutants devoid of Routes A and B, does not involve the PTS: fructose diffuses into the cell via an isoform (PtsG-F) of the major glucose permease of the PTS and is then phosphorylated by ATP and a manno(fructo)kinase (Mak+) specified by a normally cryptic 1032 bp ORF (yajF) of hitherto unknown function (Mak-o), mapping at min. 8.8 and corresponding to a peptide of 344 amino acids. Conversion of the Mak-o to the Mak+ phenotypeinvolves an A24D mutation in a putative regulatory region. PMID:11361065

  16. Genotoxicity of Graphene in Escherichia coli

    NASA Astrophysics Data System (ADS)

    Sharma, Ananya

    Rapid advances in nanotechnology necessitate assessment of the safety of nanomaterials in the resulting products and applications. One key nanomaterial attracting much interest in many areas of science and technology is graphene. Graphene is a one atom thick carbon allotrope arranged in a two-dimensional honeycomb lattice. In addition to being extremely thin, graphene has several extraordinary physical properties such as its exceptional mechanical strength, thermal stability, and high electrical conductivity. Graphene itself is relatively chemically inert and therefore pristine graphene must undergo a process called functionalization, which is combination of chemical and physical treatments that change the properties of graphene, to make it chemically active. Functionalization of graphene is of crucial importance as the end application of graphene depends on proper functionalization. In the field of medicine, graphene is currently a nanomaterial of high interest for building biosensors, DNA transistors, and probes for cancer detection. Despite the promising applications of graphene in several areas of biomedicine, there have been only few studies in recent years that focus on evaluating cytotoxicity of graphene on cells, and almost no studies that investigate how graphene exposure affects cellular genetic material. Therefore, in this study we used a novel approach to evaluate the genotoxicity, i.e., the effects of graphene on DNA, using Escherichia coli as a prokaryotic model organism.

  17. Biochemistry of homologous recombination in Escherichia coli.

    PubMed Central

    Kowalczykowski, S C; Dixon, D A; Eggleston, A K; Lauder, S D; Rehrauer, W M

    1994-01-01

    Homologous recombination is a fundamental biological process. Biochemical understanding of this process is most advanced for Escherichia coli. At least 25 gene products are involved in promoting genetic exchange. At present, this includes the RecA, RecBCD (exonuclease V), RecE (exonuclease VIII), RecF, RecG, RecJ, RecN, RecOR, RecQ, RecT, RuvAB, RuvC, SbcCD, and SSB proteins, as well as DNA polymerase I, DNA gyrase, DNA topoisomerase I, DNA ligase, and DNA helicases. The activities displayed by these enzymes include homologous DNA pairing and strand exchange, helicase, branch migration, Holliday junction binding and cleavage, nuclease, ATPase, topoisomerase, DNA binding, ATP binding, polymerase, and ligase, and, collectively, they define biochemical events that are essential for efficient recombination. In addition to these needed proteins, a cis-acting recombination hot spot known as Chi (chi: 5'-GCTGGTGG-3') plays a crucial regulatory function. The biochemical steps that comprise homologous recombination can be formally divided into four parts: (i) processing of DNA molecules into suitable recombination substrates, (ii) homologous pairing of the DNA partners and the exchange of DNA strands, (iii) extension of the nascent DNA heteroduplex; and (iv) resolution of the resulting crossover structure. This review focuses on the biochemical mechanisms underlying these steps, with particular emphases on the activities of the proteins involved and on the integration of these activities into likely biochemical pathways for recombination. Images PMID:7968921

  18. Energetics of glycylglycine transport in Escherichia coli.

    PubMed

    Cowell, J L

    1974-10-01

    The transport system for glycylglycine in Escherichia coli behaves like a shock-sensitive transport system. The initial rate of transport is reduced 85% by subjecting whole cells to osmotic shock, and glycylglycine is not transported by membrane vesicles. The energetics of transport was studied with strain ML 308-225 and its mutant DL-54, which is deficient in Ca(2+)- and Mg(2+)-stimulated adenosine 5'-triphosphatase (EC 3.6.1.3) activity. It is concluded that active transport of glycylglycine, like other shock-sensitive transport systems, has an obligatory requirement for phosphate bond energy, but not for respiration or the energized state of the membrane. The major evidence for this conclusion is as follows. (i) Uptake of glycylglycine is severely inhibited by arsenate. (ii) Oxidizable energy sources such as d-lactate, succinate, and ascorbate, which is mediated by N-methylphenazinium methylsulfate, cannot serve as energy sources for the transport of glycylglycine in DL-54, which lacks oxidative phosphorylation. (iii) When energy is supplied only from adenosine-5'-triphosphate produced by glycolysis (anaerobic transport assays with glucose as the energy source in DL-54), substantial uptake of glycylglycine is observed. (iv) When the Ca(2+)-Mg(2+)-adenosine triphosphatase activity is absent but substrate-level phosphorylations and electron transport are operating (glucose as the energy source in DL-54), transport of glycylglycine shows significant resistance to the uncouplers, dinitrophenol and carbonyl cyanide-p-trifluoromethoxyphenylhydrazone. PMID:4278690

  19. Oligosaccharide Binding in Escherichia coli Glycogen Synthase

    SciTech Connect

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

    2010-11-17

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

  20. Colonization factors of enterotoxigenic Escherichia coli.

    PubMed

    Madhavan, T P Vipin; Sakellaris, Harry

    2015-01-01

    Enterotoxigenic Escherichia coli (ETEC) is a major cause of life-threatening diarrheal disease around the world. The major aspects of ETEC virulence are colonization of the small intestine and the secretion of enterotoxins which elicit diarrhea. Intestinal colonization is mediated, in part, by adhesins displayed on the bacterial cell surface. As colonization of the intestine is the critical first step in the establishment of an infection, it represents a potential point of intervention for the prevention of infections. Therefore, colonization factors (CFs) have been important subjects of research in the field of ETEC virulence. Research in this field has revealed that ETEC possesses a large array of serologically distinct CFs that differ in composition, structure, and function. Most ETEC CFs are pili (fimbriae) or related fibrous structures, while other adhesins are simple outer membrane proteins lacking any macromolecular structure. This chapter reviews the genetics, structure, function, and regulation of ETEC CFs and how such studies have contributed to our understanding of ETEC virulence and opened up potential opportunities for the development of preventive and therapeutic interventions. PMID:25596032

  1. ESCHERICHIA COLI Gene Induction by Alkylation Treatment

    PubMed Central

    Volkert, Michael R.; Nguyen, Dinh C.; Beard, K. Christopher

    1986-01-01

    Searches for alkylation-inducible (aid) genes of Escherichia coli have been conducted by screening random fusions of the Mu-dl(ApR lac) phage for fusions showing increased β-galactosidase activity after treatment with methylating agents, but not after treatments with UV-irradiation. In this report we describe gene fusions that are specifically induced by alkylation treatments. Nine new mutants are described, and their properties are compared with the five mutants described previously. The total of 14 fusion mutants map at five distinct genetic loci. They can be further subdivided on the basis of their induction by methyl methanesulfonate (MMS) and N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). alkA, aidB and aidD are induced by both agents and appear to be regulated by ada. Neither aidC nor aidI is regulated by ada. Moreover, since aidC is induced only by MNNG and aidI is induced only by MMS, these two genes are likely to be individually regulated. Thus, there appear to be at least three different regulatory mechanisms controlling aid genes. PMID:3080354

  2. Incomplete flagellar structures in Escherichia coli mutants.

    PubMed Central

    Suzuki, T; Komeda, Y

    1981-01-01

    Escherichia coli mutants with defects in 29 flagellar genes identified so far were examined by electron microscopy for possession of incomplete flagellar structures in membrane-associated fractions. The results are discussed in consideration of the known transcriptional interaction of flagellar genes. Hook-basal body structures were detected in flaD, flaS, flaT, flbC, and hag mutants. The flaE mutant had a polyhook-basal body structure. An intact basal body appeared in flaK mutants. Putative precursors of the basal body were detected in mutants with defects in flaM, flaU, flaV, and flaY. No structures homologous to the flagellar basal body or its parts were detected in mutants with defects in flaA, flaB, flaC, flaG, flaH, flaI, flaL, flaN, flaO, flaP, flaQ, flaR, flaW, flaX, flbA, flbB, and flbD. One flaZ mutant had an incomplete flagellar basal body structure and another formed no significant structure, suggesting that flaZ is responsible for both basal body assembly and the transcription of the hag gene. Images PMID:7007337

  3. Regulation of alcohol fermentation by Escherichia coli

    SciTech Connect

    Clark, D.P.

    1986-03-01

    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. Focus is on the two final steps in alcohol synthesis, which are catalyzed by alcohol dehydrogenase and acetaldehyde CoA dehydrogenase. We have isolated a series of mutations affecting the expression of these enzymes. Some of these mutations are in the structural genes for these enzymes; others affect the regulation of the adh operon. We have recently cloned the genes coding for these enzymes and are now studying the effect of multiple copies of the adh gene on fermentative growth and its regulation. A recently invented technique, proton suicide has allowed the selection of a variety of novel mutants affecting fermentation which are presently being characterized. We have isolated a comprehensive collection of operon fusions in which the lacZ structural gene is fused to promoters that are inactive aerobically but active anaerobically. Although these genes (like adh) are only expressed under anaerobic conditions, the level of induction varies from two-fold to nearly 100-fold. The nitrogen source, medium pH, nature of the buffer, presence of alternative electron acceptors (e.g., nitrate), and other factors exert a great effect on the expression of many of these genes. In the near future we will investigate control mechanisms common to the adh operon and other anaerobically regulated genes.

  4. Kasugamycin-dependent mutants of Escherichia coli.

    PubMed Central

    Dabbs, E R

    1978-01-01

    Kasugamycin-dependent mutants have been isolated from Escherichia coli B. They were obtained through mutagenesis with ethyl methane sulfonate or nitrosoguanidine in conjunction with an antibiotic underlay technique. In the case of nitrosoguanidine, dependent mutants were obtained at a frequency of about 3% of survivors growing up in the selection. In the case of ethyl methane sulfonate, the corresponding value was 1%. Nineteen mutants showing a kasugamycin-dependent phenotype were studied. In terms of response to various temperatures and antibiotic concentrations, they were very heterogeneous, although most fell into two general classes. Genetic analysis indicated that in at least some cases, the kasugamycin-dependent phenotype was the product of two mutations. Two-dimensional gel electropherograms revealed alterations in the ribosomal proteins of seven mutants. One mutant had an alteration in protein S13, and one had an alteration in protein L14. Three showed changes in protein S9. Each of two mutants had changes in two proteins, S18 and L11. Three of these mutants additionally had protein S18 occurring in a partly altered, partly unaltered form. Images PMID:363701

  5. The Escherichia coli divisome: born to divide.

    PubMed

    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

  6. EFFECT OF MANURE ON ESCHERICHIA COLI ATTACHMENT TO SOIL FRACTIONS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Escherichia coli are commonly used as indicators of fecal contamination in the environment. Attachment of bacteria to soil and sediment is an important retardation factor of bacterial transport with runoff water. Despite the fact that E. coli are derived exclusively from feces/manure, the effect of ...

  7. Complete Genome Sequence of Enterotoxigenic Escherichia coli Myophage Murica

    PubMed Central

    Wilder, Joseph N.; Lancaster, Jacob C.; Cahill, Jesse L.; Rasche, Eric S.

    2015-01-01

    Murica is an rv5-like myophage that infects enterotoxigenic Escherichia coli. Pathogenic E. coli strains are responsible for many intestinal diseases, and phages that infect these bacteria may prove useful in preventing severe health issues. The following is a report of the complete genome sequence of Murica and its important features. PMID:26430048

  8. Complete Genome Sequence of Enterotoxigenic Escherichia coli Myophage Murica.

    PubMed

    Wilder, Joseph N; Lancaster, Jacob C; Cahill, Jesse L; Rasche, Eric S; Kuty Everett, Gabriel F

    2015-01-01

    Murica is an rv5-like myophage that infects enterotoxigenic Escherichia coli. Pathogenic E. coli strains are responsible for many intestinal diseases, and phages that infect these bacteria may prove useful in preventing severe health issues. The following is a report of the complete genome sequence of Murica and its important features. PMID:26430048

  9. Complete Draft Genome Sequence of Escherichia coli JF733

    PubMed Central

    Kleiner, Gabriele R. M.; Wibberg, Daniel; Winkler, Anika; Wertz, John E.; Friehs, Karl

    2016-01-01

    Escherichia coli JF733 is a strain with a long history in research on membrane proteins and processes. However, tracing back the strain development raises some questions concerning the correct genotype of JF733. Here, we present the complete draft genome of E. coli JF733 in order to resolve any remaining uncertainties. PMID:27103723

  10. Molecular Serotyping of Escherichia coli O111:H8

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Accurate Escherichia coli serotyping is critical for pathogen diagnosis and surveillance of non-O157 shiga-toxigenic strains, however, few laboratories have this capacity. The molecular serotyping protocol described in this paper targets the somatic and flagellar antigens of E. coli O111:H8 used in...

  11. Properties and Transport Behavior among 12 Different Environmental Escherichia coli

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Escherichia coli is a commonly used indicator organism for detecting the presence of fecal-borne pathogenic microorganisms in water supplies. The importance of E. coli as an indicator organism has led to numerous studies looking at cell properties and transport behavior of this microorganism. In man...

  12. Complete Draft Genome Sequence of Escherichia coli JF733.

    PubMed

    Kleiner, Gabriele R M; Wibberg, Daniel; Winkler, Anika; Kalinowski, Jörn; Wertz, John E; Friehs, Karl

    2016-01-01

    ITALIC! Escherichia coliJF733 is a strain with a long history in research on membrane proteins and processes. However, tracing back the strain development raises some questions concerning the correct genotype of JF733. Here, we present the complete draft genome of ITALIC! E. coliJF733 in order to resolve any remaining uncertainties. PMID:27103723

  13. Stringency of substrate specificity of Escherichia coli malate dehydrogenase.

    SciTech Connect

    Boernke, W. E.; Millard, C. S.; Stevens, P. W.; Kakar, S. N.; Stevens, F. J.; Donnelly, M. I.; Nebraska Wesleyan Univ.

    1995-09-10

    Malate dehydrogenase and lactate dehydrogenase are members of the structurally and functionally homologous family of 2-ketoacid dehydrogenases. Both enzymes display high specificity for their respective keto substrates, oxaloacetate and pyruvate. Closer analysis of their specificity, however, reveals that the specificity of malate dehydrogenase is much stricter and less malleable than that of lactate dehydrogenase. Site-specific mutagenesis of the two enzymes in an attempt to reverse their specificity has met with contrary results. Conversion of a specific active-site glutamine to arginine in lactate dehydrogenase from Bacillus stearothermophilus generated an enzyme that displayed activity toward oxaloacetate equal to that of the native enzyme toward pyruvate (H. M. Wilks et al. (1988) Science 242, 1541-1544). We have constructed a series of mutants in the mobile, active site loop of the Escherichia coli malate dehydrogenase that incorporate the complementary change, conversion of arginine 81 to glutamine, to evaluate the role of charge distribution and conformational flexibility within this loop in defining the substrate specificity of these enzymes. Mutants incorporating the change R81Q all had reversed specificity, displaying much higher activity toward pyruvate than to the natural substrate, oxaloacetate. In contrast to the mutated lactate dehydrogenase, these reversed-specificity mutants were much less active than the native enzyme. Secondary mutations within the loop of the E. coli enzyme (A80N, A80P, A80P/M85E/D86T) had either no or only moderately beneficial effects on the activity of the mutant enzyme toward pyruvate. The mutation A80P, which can be expected to reduce the overall flexibility of the loop, modestly improved activity toward pyruvate. The possible physiological relevance of the stringent specificity of malate dehydrogenase was investigated. In normal strains of E. coli, fermentative metabolism was not affected by expression of the mutant

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

    PubMed

    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

  15. Soil solarization reduces Escherichia coli O157:H7 and total Escherichia coli on cattle feedlot pen surfaces

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Feedlot pen soils are a source for transmission of Escherichia coli O157:H7, and therefore a target for preharvest strategies to reduce this pathogen in cattle. The objective of this study was to determine the ability of soil solarization to reduce E. coli O157:H7 in feedlot surface material (FSM)....

  16. Inactivation of Escherichia coli O157:H7 and Escherichia coli 8739 in apple juice by pulsed electric fields.

    PubMed

    Evrendilek, G A; Zhang, Q H; Richter, E R

    1999-07-01

    The effect of high voltage pulsed electric field (PEF) treatment on Escherichia coli O157:H7 and generic E. coli 8739 in apple juice was investigated. Fresh apple juice samples inoculated with E. coli O157:H7 and E. coli 8739 were treated by PEF with selected parameters including electric field strength, treatment time, and treatment temperature. Samples were exposed to bipolar pulses with electric field strengths of 30, 26, 22, and 18 kV/cm and total treatment times of 172, 144, 115, and 86 micros. A 5-log reduction in both cultures was determined by a standard nonselective medium spread plate laboratory procedure. Treatment temperature was kept below 35 degrees C. Results showed no difference in the sensitivities of E. coli O157:H7 and E. coli 8739 against PEF treatment. PEF is a promising technology for the inactivation of E. coli O157:H7 and E. coli 8739 in apple juice. PMID:10419274

  17. Systematic Mutagenesis of the Escherichia coli Genome†

    PubMed Central

    Kang, Yisheng; Durfee, Tim; Glasner, Jeremy D.; Qiu, Yu; Frisch, David; Winterberg, Kelly M.; Blattner, Frederick R.

    2004-01-01

    A high-throughput method has been developed for the systematic mutagenesis of the Escherichia coli genome. The system is based on in vitro transposition of a modified Tn5 element, the Sce-poson, into linear fragments of each open reading frame. The transposon introduces both positive (kanamycin resistance) and negative (I-SceI recognition site) selectable markers for isolation of mutants and subsequent allele replacement, respectively. Reaction products are then introduced into the genome by homologous recombination via the λRed proteins. The method has yielded insertion alleles for 1976 genes during a first pass through the genome including, unexpectedly, a number of known and putative essential genes. Sce-poson insertions can be easily replaced by markerless mutations by using the I-SceI homing endonuclease to select against retention of the transposon as demonstrated by the substitution of amber and/or in-frame deletions in six different genes. This allows a Sce-poson-containing gene to be specifically targeted for either designed or random modifications, as well as permitting the stepwise engineering of strains with multiple mutations. The promiscuous nature of Tn5 transposition also enables a targeted gene to be dissected by using randomly inserted Sce-posons as shown by a lacZ allelic series. Finally, assessment of the insertion sites by an iterative weighted matrix algorithm reveals that these hyperactive Tn5 complexes generally recognize a highly degenerate asymmetric motif on one end of the target site helping to explain the randomness of Tn5 transposition. PMID:15262929

  18. The Melibiose Transporter of Escherichia coli

    PubMed Central

    Fuerst, Oliver; Lin, Yibin; Granell, Meritxell; Leblanc, Gérard; Padrós, Esteve; Lórenz-Fonfría, Víctor A.; Cladera, Josep

    2015-01-01

    We examine the role of Lys-377, the only charged residue in helix XI, on the functional mechanism of the Na+-sugar melibiose symporter from Escherichia coli. Intrinsic fluorescence, FRET, and Fourier transform infrared difference spectroscopy reveal that replacement of Lys-377 with either Cys, Val, Arg, or Asp disables both Na+ and melibiose binding. On the other hand, molecular dynamics simulations extending up to 200–330 ns reveal that Lys-377 (helix XI) interacts with the anionic side chains of two of the three putative ligands for cation binding (Asp-55 and Asp-59 in helix II). When Asp-59 is protonated during the simulations, Lys-377 preferentially interacts with Asp-55. Interestingly, when a Na+ ion is positioned in the Asp-55-Asp-59 environment, Asp-124 in helix IV (a residue essential for melibiose binding) reorients and approximates the Asp-55-Asp-59 pair, and all three acidic side chains act as Na+ ligands. Under these conditions, the side chain of Lys-377 interacts with the carboxylic moiety of these three Asp residues. These data highlight the crucial role of the Lys-377 residue in the spatial organization of the Na+ binding site. Finally, the analysis of the second-site revertants of K377C reveals that mutation of Ile-22 (in helix I) preserves Na+ binding, whereas that of melibiose is largely abolished according to spectroscopic measurements. This amino acid is located in the border of the sugar-binding site and might participate in sugar binding through apolar interactions. PMID:25971963

  19. Routes of quinolone permeation in Escherichia coli.

    PubMed Central

    Chapman, J S; Georgopapadakou, N H

    1988-01-01

    The uptake of quinolone antibiotics by Escherichia coli was investigated by using fleroxacin (RO 23-6240, AM 833) as a prototype compound. The uptake of fleroxacin was reduced and its MIC was increased in the presence of magnesium. Quinolones induced lipopolysaccharide release, increased cell-surface hydrophobicity and outer membrane permeability to B-lactams, and sensitized cells to lysis by detergents. These effects were also antagonized by magnesium and were very similar to those seen with EDTA and gentamicin. MICs of quinolones in portin-deficient strains were increased relative to those of the parent strain, consistent with a porin pathway of entry. However, MICs were further increased in the presence of magnesium; the size of the additional increase showed a positive correlation with quinolone hydrophobicity in an OmpF- OmpC- OmpA- strain. When quinolones were mixed with divalent cations in solution, changes in quinolone fluorescence suggestive of metal chelation were observed. The addition of fleroxacin to a cell suspension resulted in a rapid initial association of fluorescence with cells, followed by a brief decrease and a final time-dependent linear increase in cell-associated fluorescence. We interpret these results as representing chelation of outer membrane-bound magnesium by fleroxacin and other quinolones, dissociation of the quinolone-magnesium complex from the outer membrane, and diffusion of the quinolone through both porins and exposed lipid domains on the outer membrane. For a given quinolone, the contribution of the porin and nonporin pathways to total uptake is influenced by the hydrophobicity of the quinolone. PMID:3132091

  20. Serogroups of Escherichia coli from drinking water.

    PubMed

    Ramteke, P W; Tewari, Suman

    2007-07-01

    Fifty seven isolates of thermotolerant E. coli were recovered from 188 drinking water sources, 45 (78.9%) were typable of which 15 (26.3%) were pathogenic serotypes. Pathogenic serogroup obtained were 04 (Uropathogenic E. coli, UPEC), 025 (Enterotoxigenic E. coli, ETEC), 086 (Enteropathogenic E. coli, EPEC), 0103 (Shiga-toxin producing E. coli, STEC), 0157 (Shiga-toxin producing E. coli, STEC), 08 (Enterotoxigenic E. coli, ETEC) and 0113 (Shiga-toxin producing E. coli, STEC). All the pathogenic serotypes showed resistance to bacitracin and multiple heavy metal ions. Resistance to streptomycin and cotrimazole was detected in two strains whereas resistance to cephaloridine, polymixin-B and ampicillin was detected in one strain each. Transfer of resistances to drugs and metallic ions was observed in 9 out of 12 strains studied. Resistances to bacitracin were transferred in all nine strains. Among heavy metals resistance to As(3+) followed by Cr(6+) were transferred more frequently. PMID:17057960

  1. Rapid Sterilization of Escherichia coli by Solution Plasma Process

    NASA Astrophysics Data System (ADS)

    Andreeva, Nina; Ishizaki, Takahiro; Baroch, Pavel; Saito, Nagahiro

    2012-12-01

    Solution plasma (SP), which is a discharge in the liquid phase, has the potential for rapid sterilization of water without chemical agents. The discharge showed a strong sterilization performance against Escherichia coli bacteria. The decimal value (D value) of the reduction time for E. coli by this system with an electrode distance of 1.0 mm was estimated to be approximately 1.0 min. Our discharge system in the liquid phase caused no physical damage to the E. coli and only a small increase in the temperature of the aqueous solution. The UV light generated by the discharge was an important factor in the sterilization of E. coli.

  2. Relevance of class 1 integrons and extended-spectrum β-lactamases in drug-resistant Escherichia coli.

    PubMed

    Liu, Li-Tao; Wan, Li-Hong; Song, Xiao-Hong; Xiong, Yao; Jin, Shao-Ju; Zhou, Li-Ming

    2013-10-01

    Escherichia coli is a common cause of community‑ and hospital‑acquired urinary tract infections, and class 1 integrons are the prior elements of gene transference in the capture and distribution of gene cassettes among clinical gram-negative bacillus. In the present study, the resistance of Escherichia coli to antimicrobial agents was investigated. A total of 97 isolates were found to be susceptible to 16 antimicrobial agents and were detected in the production of extended β‑lactamases (ESBLs), distribution of CTX‑M‑type β‑lactamases, presence and characterization of class 1 integrons and a variable region of integron‑positive isolates. Escherichia coli isolates possessing CTX‑M (31; 32%) were detected in 19 isolates (61.5%). The presence of ESBLs was associated with resistance to penicillins, third-generation cephalosporins, ciprofloxacin, aminoglycosides and monocyclic β‑lactam antibiotics. Escherichia coli isolates (69; 71.1%) possessed class 1 integrons associated with resistance to ciprofloxacin and numerous third-generation cephalosporins, penicillins, tobramycin and trimethoprim‑sulfamethoxazole. The four gene cassette arrangements were as follows: dfrA17‑aadA5, aadA1, aacC4‑cmlA1 and dfr2d, and 8 carried two disparate class 1 integrons. Five isolates presented class 1 integrons containing no gene cassettes. The distribution of ESBLs and class 1 integrons in Escherichia coli were prevalent with drug resistance in Chengdu. In addition, the resistance range of Escherichia coli isolates that harboured ESBLs and carried class 1 integrons were similar. The current study demonstrated the presence of class 1 integrons and ESBLs, which jointly mediate the resistance of Escherichia coli isolates to a number of antibacterial agents. PMID:23939784

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

    PubMed

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

    1992-05-01

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

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

    PubMed Central

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

    1992-01-01

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

  5. The Biology of the Escherichia coli Extracellular Matrix

    PubMed Central

    Hufnagel, David A.; DePas, William H.; Chapman, Matthew R.

    2015-01-01

    Chapter Summary Escherichia coli (E. coli) is one of the world’s best-characterized organisms, as it has been extensively studied for over a century. However, most of this work has focused on E. coli grown under laboratory conditions that do not faithfully simulate its natural environments. Therefore, the historical perspectives on E. coli physiology and life cycle are somewhat skewed toward experimental systems that feature E. coli growing logarithmically in a test tube. Typically a commensal bacterium, E. coli resides in the lower intestines of a slew of animals. Outside of the lower intestine, E. coli can adapt and survive in a very different set of environmental conditions. Biofilm formation allows E. coli to survive, and even thrive, in environments that do not support the growth of planktonic populations. E. coli can form biofilms virtually everywhere; in the bladder during a urinary tract infection, on in-dwelling medical devices, and outside of the host on plants and in the soil. The E. coli extracellular matrix, primarily composed of the protein polymer named curli and the polysaccharide cellulose, promotes adherence to organic and inorganic surfaces, and resistance to desiccation, the host immune system and other antimicrobials. The pathways that govern E. coli biofilm formation, cellulose production, and curli biogenesis will be discussed in this book chapter, which concludes with insights into the future of E. coli biofilm research and potential therapies. PMID:26185090

  6. Binding studies of antimicrobial peptides to Escherichia coli cells.

    PubMed

    Avitabile, Concetta; D'Andrea, Luca D; Saviano, Michele; Olivieri, Michele; Cimmino, Amelia; Romanelli, Alessandra

    2016-09-01

    Understanding the mechanism of action of antimicrobial peptides is pivotal to the design of new and more active peptides. In the last few years it has become clear that the behavior of antimicrobial peptides on membrane model systems does not always translate to cells; therefore the need to develop methods aimed at capturing details of the interactions of peptides with bacterial cells is compelling. In this work we analyzed binding of two peptides, namely temporin B and TB_KKG6A, to Escherichia coli cells and to Escherichia coli LPS. Temporin B is a natural peptide active against Gram positive bacteria but inactive against Gram negative bacteria, TB_KKG6A is an analogue of temporin B showing activity against both Gram positive and Gram negative bacteria. We found that binding to cells occurs only for the active peptide TB_KKG6A; stoichiometry and affinity constant of this peptide toward Escherichia coli cells were determined. PMID:27450805

  7. Infection by verocytotoxin-producing Escherichia coli.

    PubMed Central

    Karmali, M A

    1989-01-01

    Verocytotoxin (VT)-producing Escherichia coli (VTEC) are a newly recognized group of enteric pathogens which are increasingly being recognized as common causes of diarrhea in some geographic settings. Outbreak studies indicate that most patients with VTEC infection develop mild uncomplicated diarrhea. However, a significant risk of two serious and potentially life-threatening complications, hemorrhagic colitis and the hemolytic uremic syndrome, makes VTEC infection a public health problem of serious concern. The main reservoirs of VTEC appear to be the intestinal tracts of animals, and foods of animal (especially bovine) origin are probably the principal sources for human infection. The term VT refers to a family of subunit exotoxins with high biological activity. Individual VTEC strains elaborate one or both of at least two serologically distinct, bacteriophage-mediated VTs (VT1 and VT2) which are closely related to Shiga toxin and are thus also referred to as Shiga-like toxins. The holotoxins bind to cells, via their B subunits, to a specific receptor which is probably the glycolipid, globotriosyl ceramide (Gb3). Binding is followed by internalization of the A subunit, which, after it is proteolytically nicked and reduced to the A1 fragment, inhibits protein synthesis in mammalian cells by inactivating 60S ribosomal subunits through selective structural modification of 28S ribosomal ribonucleic acid. The mechanism of VTEC diarrhea is still controversial, and the relative roles of locally acting VT and "attaching and effacing adherence" of VTEC to the mucosa have yet to be resolved. There is increasing evidence that hemolytic uremic syndrome and possibly hemorrhagic colitis result from the systemic action of VT on vascular endothelial cells. The role of antitoxic immunity in preventing the systemic complications of VTEC infection is being explored. Antibiotics appear to be contraindicated in the treatment of VTEC infection. The most common VTEC serotype associated

  8. Recurrent Hemolytic and Uremic Syndrome Induced by Escherichia Coli

    PubMed Central

    Commereuc, Morgane; Weill, Francois-Xavier; Loukiadis, Estelle; Gouali, Malika; Gleizal, Audrey; Kormann, Raphaël; Ridel, Christophe; Frémeaux-Bacchi, Véronique; Rondeau, Eric; Hertig, Alexandre

    2016-01-01

    Abstract A widespread belief is that typical hemolytic and uremic syndrome (HUS) does not recur. We report the case of a patient infected twice with raw milk taken from his own cow and containing a Shiga toxin–producing Escherichia coli O174:H21 that induced recurrent HUS causing severe renal and cerebral disorders. A genomic comparison of the human and bovine Shiga toxin–producing Escherichia coli O174:H21 isolates revealed that they were identical. Typical HUS may recur. Since milk from this animal was occasionally distributed locally, thereby posing a serious threat for the whole village, this particular cow was destroyed. PMID:26735524

  9. Recurrent Hemolytic and Uremic Syndrome Induced by Escherichia Coli.

    PubMed

    Commereuc, Morgane; Weill, Francois-Xavier; Loukiadis, Estelle; Gouali, Malika; Gleizal, Audrey; Kormann, Raphaël; Ridel, Christophe; Frémeaux-Bacchi, Véronique; Rondeau, Eric; Hertig, Alexandre

    2016-01-01

    A widespread belief is that typical hemolytic and uremic syndrome (HUS) does not recur. We report the case of a patient infected twice with raw milk taken from his own cow and containing a Shiga toxin-producing Escherichia coli O174:H21 that induced recurrent HUS causing severe renal and cerebral disorders. A genomic comparison of the human and bovine Shiga toxin-producing Escherichia coli O174:H21 isolates revealed that they were identical. Typical HUS may recur. Since milk from this animal was occasionally distributed locally, thereby posing a serious threat for the whole village, this particular cow was destroyed. PMID:26735524

  10. Recent advances in adherence and invasion of pathogenic Escherichia coli

    PubMed Central

    Kalita, Anjana; Hu, Jia; Torres, Alfredo G.

    2014-01-01

    Purpose of review Colonization of the host epithelia by pathogenic Escherichia coli is influenced by the ability of the bacteria to interact with host surfaces. Because the initial step of an E. coli infection is to adhere, invade, and persist within host cells, some strategies used by intestinal and extra-intestinal E. coli to infect host cell are presented. Recent findings This review highlights recent progress understanding how extra-intestinal pathogenic E. coli strains express specific adhesins/invasins that allow colonization of the urinary tract or the meninges, while intestinal E. coli strains are able to colonize different regions of the intestinal tract using other specialized adhesins/invasins. Finally, evaluation of, different diets and environmental conditions regulating the colonization of these pathogens is discussed. Summary Discovery of new interactions between pathogenic E. coli and the host epithelial cells unravels the need of more mechanistic studies that can provide new clues in how to combat these infections. PMID:25023740

  11. Virulence attributes of Escherichia coli isolated from dairy heifer feces.

    PubMed

    Cray, W C; Thomas, L A; Schneider, R A; Moon, H W

    1996-12-01

    Escherichia coli isolates from 1,305 (of 6,894) fecal samples collected during the 1991-1992 USDA, Animal and Plant Health Inspection Service, National Health Monitoring System, Diary Heifer Evaluation Project were tested for virulence attributes associated with human enterohaemorrhagic E. coli (EHEC) and the enterotoxin commonly associated with diarrhoea in newborn calves. Single, random isolates from each heifer were hybridized to probes derived from the 60 mDa EHEC plasmid (CVD 419), E. coli attaching and effacing gene (eae), Shiga-like toxin (slt) genes I and II, and E. coli heat-stable enterotoxin a (STaP). Seventy-seven of the 1305 isolates (5.9%) were slt-positive. Most (81.8%) slt-positive E. coli were also CVD 419 and eae-positive. Only 2 of the slt-positive E. coli isolates were STaP-positive. PMID:9008347

  12. Transcription of foreign DNA in Escherichia coli

    PubMed Central

    Warren, René L.; Freeman, John D.; Levesque, Roger C.; Smailus, Duane E.; Flibotte, Stephane; Holt, Robert A.

    2008-01-01

    Propagation of heterologous DNA in E. coli host cells is central to molecular biology. DNA constructs are often engineered for expression of recombinant protein in E. coli, but the extent of incidental transcription arising from natural regulatory sequences in cloned DNA remains underexplored. Here, we have used programmable microarrays and RT-PCR to measure, comprehensively, the transcription of H. influenzae, P. aeruginosa, and human DNA propagating in E. coli as bacterial artificial chromosomes. We find evidence that at least half of all H. influenzae genes are transcribed in E. coli. Highly transcribed genes are principally involved in energy metabolism, and their proximal promoter regions are significantly enriched with E. coli σ70 (also known as RpoD) binding sites. H. influenzae genes acquired from an ancient bacteriophage Mu insertion are also highly transcribed. Compared with H. influenzae, a smaller proportion of P. aeruginosa genes are transcribed in E. coli, and in E. coli there is punctuated transcription of human DNA. The presence of foreign DNA in E. coli disturbs the host transcriptional profile, with expression of the E. coli phage shock protein operon and the flagellar gene cluster being particularly strongly up-regulated. While cross-species transcriptional activation is expected to be enabling for horizontal gene transfer in bacteria, incidental expression of toxic genes can be problematic for DNA cloning. Ongoing characterization of cross-expression will help inform the design of biosynthetic gene clusters and synthetic microbial genomes. PMID:18701636

  13. Genes and proteins of Escherichia coli K-12.

    PubMed

    Riley, M

    1998-01-01

    GenProtEC is a database of Escherichia coli genes and their gene products, classified by type of function and physiological role and with citations to the literature for each. Also present are data on sequence similarities among E.coli proteins, representing groups of paralogous genes, with PAM values, percent identity of amino acids, length of alignment and percent aligned. GenProtEC can be accessed at the URL http://www.mbl.edu/html/ecoli.html PMID:9399799

  14. Alkyl hydroperoxide reductase from Bacillus aquimaris MKSC 6.2 protects Esherichia coli from oxidative stress.

    PubMed

    Natalia, Dessy; Jumadila, Ozi; Anggraini, Irika Devi; Meutia, Febrina; Puspasari, Fernita; Hasan, Khomaini

    2016-07-01

    Alkyl hydroperoxide reductase genes (ahpCF) from the soft coral associated Bacillus aquimaris MKSC6.2 have been isolated. The cloned 546 bp ahpC gene encodes a 181 amino acid residues polypeptide. The AhpC belongs to typical 2-Cys peroxiredoxin (Prx) containing conserved peroxidatic cysteine residue (C46 ) required for hydroperoxide reduction and conserved resolving cysteine (C166 ). The isolated 1530 bp ahpF gene encodes a polypeptide of 509 amino acid residues with two conserved C128 HNC131 and C337 PHC340 catalytic residues required for reduction of oxidized-AhpC during catalytic turnover. A survival study with Escherichia coli showed that overexpression of AhpC and AhpF resulted in a total protection against 0.16 mM t-butyl hydroperoxide. PMID:26523844

  15. YeeO from Escherichia coli exports flavins

    PubMed Central

    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

  16. Characterization of pili associated with Escherichia coli O18ac.

    PubMed Central

    Wevers, P; Picken, R; Schmidt, G; Jann, B; Jann, K; Golecki, J R; Kist, M

    1980-01-01

    A strain of Escherichia coli O18ac isolated from the stool sample of a patient with diarrhea was found to agglutinate human erythrocytes. From the results presented it is suggested that this hemagglutination is mediated by pili. Isolated pilus preparations agglutinated human erythrocytes, whereas pilus-negative mutants did not. The serological and chemical analyses indicate that the pili associated with E. coli O18ac are distinct from other types found with E. coli. Images Fig. 1 Fig. 2 Fig. 3 PMID:6111534

  17. An integrated database to support research on Escherichia coli

    SciTech Connect

    Baehr, A.; Dunham, G.; Matsuda, Hideo; Michaels, G.; Taylor, R.; Overbeek, R.; Rudd, K.E. ); Ginsburg, A.; Joerg, D.; Kazic, T. . Dept. of Genetics); Hagstrom, R.; Zawada, D. ); Smith, C.; Yoshida, Kaoru )

    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.

  18. YeeO from Escherichia coli exports flavins.

    PubMed

    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

  19. Enteropathogenic Escherichia coli Serotypes and Endemic Diarrhea in Infants

    PubMed Central

    Toledo, M. Regina F.; Alvariza, M. do Carmo B.; Murahovschi, Jayme; Ramos, Sonia R. T. S.; Trabulsi, Luiz R.

    1983-01-01

    Enteropathogenic Escherichia coli serotypes were searched for in feces of 550 children with endemic diarrhea and in 129 controls, in São Paulo, in 1978 and 1979; serotypes O111ab:H−, O111ab:H2, and O119:H6 were significantly associated with diarrhea in children 0 to 5 months old and were the most frequent agents of diarrhea in this age group as compared with enterotoxigenic and enteroinvasive E. coli, Salmonella sp., Shigella sp., and Yersinia enterocolitica. It is concluded that various enteropathogenic E. coli serotypes may be agents of endemic infantile diarrhea. PMID:6339384

  20. The quantitative and condition-dependent Escherichia coli proteome

    PubMed Central

    Schmidt, Alexander; Kochanowski, Karl; Vedelaar, Silke; Ahrné, Erik; Volkmer, Benjamin; Callipo, Luciano; Knoops, Kèvin; Bauer, Manuel; Aebersold, Ruedi; Heinemann, Matthias

    2016-01-01

    Measuring precise concentrations of proteins can provide insights into biological processes. Here, we use efficient protein extraction and sample fractionation and state-of-the-art quantitative mass spectrometry techniques to generate a comprehensive, condition-dependent protein abundance map of Escherichia coli. We measure cellular protein concentrations for 55% of predicted E. coli genes (>2300 proteins) under 22 different experimental conditions and identify methylation and N-terminal protein acetylations previously not known to be prevalent in bacteria. We uncover system-wide proteome allocation, expression regulation, and post-translational adaptations. These data provide a valuable resource for the systems biology and broader E. coli research communities. PMID:26641532

  1. Molecular characterization of diarrheagenic Escherichia coli from Libya.

    PubMed

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

    2012-05-01

    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

  2. Molecular Characterization of Diarrheagenic Escherichia coli from Libya

    PubMed Central

    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

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

    PubMed Central

    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

    2016-01-01

    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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  5. Isolation of an Lc-specific Escherichia coli bacteriophage.

    PubMed Central

    Fralick, J A; Diedrich, D L; Casey-Wood, S

    1990-01-01

    We isolated an OmpF-specific bacteriophage whose host range mutant, SQ108h2, requires the presence of the Lc porin for its attachment and which can be used to screen or select for Lc-defective mutants among Escherichia coli K-12 strains lysogenic for the PA-2 converting phage. Images FIG. 1 PMID:1689719

  6. Inactivation of Escherichia coli by titanium dioxide photocatalytic oxidation.

    EPA Science Inventory

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

  7. Non-O157 Shiga toxin-producing Escherichia coli

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Shiga toxin-producing Escherichia coli (STEC) O157:H7 is a leading cause of food-borne illness in the United States; however, recent reports have shown that non-O157 STEC serogroups contribute to more illnesses than O157:H7. Illness caused by non-O157 STEC strains are generally less severe than tho...

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

    PubMed

    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

  9. TRIMETHOPRIM-SULFAMETHOXAZOLE RESISTANCE IN SEWAGE ISOLATES OF ESCHERICHIA COLI

    EPA Science Inventory

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

  10. Genotypic Characterization of Enterotoxigenic Escherichia coli Strains Causing Traveler's Diarrhea

    PubMed Central

    Rivera, Fulton P.; Medina, Anicia M.; Aldasoro, Edelweiss; Sangil, Anna; Gascon, Joaquim; Ochoa, Theresa J.; Vila, Jordi

    2013-01-01

    This study aims to characterize the presence of virulence factors of enterotoxigenic Escherichia coli (ETEC) causing traveler's diarrhea. Among 52 ETEC isolates, the most common toxin type was STh, and the most frequent colonization factors (CFs) were CS21, CS6, and CS3. On the other hand, the nonclassical virulence factors EAST1 and EatA were frequently present. PMID:23224092

  11. 21 CFR 866.3255 - Escherichia coli serological reagents.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Escherichia coli serological reagents. 866.3255 Section 866.3255 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3255...

  12. 21 CFR 866.3255 - Escherichia coli serological reagents.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Escherichia coli serological reagents. 866.3255 Section 866.3255 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3255...

  13. 21 CFR 866.3255 - Escherichia coli serological reagents.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Escherichia coli serological reagents. 866.3255 Section 866.3255 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3255...

  14. 21 CFR 866.3255 - Escherichia coli serological reagents.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Escherichia coli serological reagents. 866.3255 Section 866.3255 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3255...

  15. 21 CFR 866.3255 - Escherichia coli serological reagents.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Escherichia coli serological reagents. 866.3255 Section 866.3255 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3255...

  16. Identification of the Escherichia coli Nicotinic Acid Mononucleotide Adenylyltransferase Gene

    PubMed Central

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

    2000-01-01

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

  17. Effects of low concentrations of antibiotics on Escherichia coli adhesion.

    PubMed Central

    Vosbeck, K; Mett, H; Huber, U; Bohn, J; Petignat, M

    1982-01-01

    We have previously shown that subinhibitory concentrations of antibiotics may influence the adhesion of Escherichia coli SS142 to human epithelioid tissue culture cells. This report shows that these effects are not limited to E. coli SS142 or to our tissue culture system. Most of the 10 E. coli strains studied showed decreased adhesion to Intestine 407 tissue culture cells after growth in 25% of the minimum inhibitory concentration of streptomycin, tetracycline, trimethoprimsulfametrole, chloramphenicol, and clindamycin. Nalidixic acid at 25% of the minimum inhibitory concentration caused an increase of adhesion. The hemagglutinating activity of the five hemagglutinating strains and the adhesiveness of E. coli SS142 to human buccal cells were similarly affected by low concentrations of the above-mentioned antibiotics. We conclude that E. coli adhesion to human epithelioid tissue culture cells is a valid model of bacterial adhesion because of its high accuracy and reproducibility. PMID:7051972

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

    PubMed

    Coura, Fernanda Morcatti; 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

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

    PubMed Central

    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

  20. Production of itaconic acid in Escherichia coli expressing recombinant α-amylase using starch as substrate.

    PubMed

    Okamoto, Shusuke; Chin, Taejun; Nagata, Keisuke; Takahashi, Tetsuya; Ohara, Hitomi; Aso, Yuji

    2015-05-01

    Several studies on fermentative production of a vinyl monomer itaconic acid from hydrolyzed starch using Aspergillus terreus have been reported. Herein, we report itaconic acid production by Escherichia coli expressing recombinant α-amylase, using soluble starch as its sole carbon source. To express α-amylase in E. coli, we first constructed recombinant plasmids expressing α-amylases by using cell surface display technology derived from two amylolytic bacteria, Bacillus amyloliquefaciens NBRC 15535(T) and Streptococcus bovis NRIC 1535. The recombinant α-amylase from S. bovis (SBA) showed activity at 28°C, which is the optimal temperature for production of itaconic acid, while α-amylase from B. amyloliquefaciens displayed no noticeable activity. E. coli cells expressing SBA produced 0.15 g/L itaconic acid after 69 h cultivation under pH-stat conditions, using 1% starch as the sole carbon source. In fact, E. coli cells expressing SBA had similar growth rates when grown in the presence of 1% glucose or starch, thereby highlighting the expression of an active α-amylase that enabled utilization of starch to produce itaconic acid in E. coli. PMID:25468427

  1. Study of the effects of high-energy proton beams on escherichia coli

    NASA Astrophysics Data System (ADS)

    Park, Jeong Chan; Jung, Myung-Hwan

    2015-10-01

    Antibiotic-resistant bacterial infection is one of the most serious risks to public health care today. However, discouragingly, the development of new antibiotics has progressed little over the last decade. There is an urgent need for alternative approaches to treat antibiotic-resistant bacteria. Novel methods, which include photothermal therapy based on gold nano-materials and ionizing radiation such as X-rays and gamma rays, have been reported. Studies of the effects of high-energy proton radiation on bacteria have mainly focused on Bacillus species and its spores. The effect of proton beams on Escherichia coli (E. coli) has been limitedly reported. Escherichia coli is an important biological tool to obtain metabolic and genetic information and is a common model microorganism for studying toxicity and antimicrobial activity. In addition, E. coli is a common bacterium in the intestinal tract of mammals. In this research, the morphological and the physiological changes of E. coli after proton irradiation were investigated. Diluted solutions of cells were used for proton beam radiation. LB agar plates were used to count the number of colonies formed. The growth profile of the cells was monitored by using the optical density at 600 nm. The morphology of the irradiated cells was observed with an optical microscope. A microarray analysis was performed to examine the gene expression changes between irradiated samples and control samples without irradiation. E coli cells have observed to be elongated after proton irradiation with doses ranging from 13 to 93 Gy. Twenty-two were up-regulated more than twofold in proton-irradiated samples (93 Gy) compared with unexposed one.

  2. Lytic bacteriophages reduce Escherichia coli O157

    PubMed Central

    Ferguson, Sean; Roberts, Cheryl; Handy, Eric; Sharma, Manan

    2013-01-01

    The role of lytic bacteriophages in preventing cross contamination of produce has not been evaluated. A cocktail of three lytic phages specific for E. coli O157:H7 (EcoShield™) or a control (phosphate buffered saline, PBS) was applied to lettuce by either; (1) immersion of lettuce in 500 ml of EcoShield™ 8.3 log PFU/ml or 9.8 log PFU/ml for up to 2 min before inoculation with E. coli O157:H7; (2) spray-application of EcoShield™ (9.3 log PFU/ml) to lettuce after inoculation with E. coli O157:H7 (4.10 CFU/cm2) following exposure to 50 μg/ml chlorine for 30 sec. After immersion studies, lettuce was spot-inoculated with E. coli O157:H7 (2.38 CFU/cm2). Phage-treated, inoculated lettuce pieces were stored at 4°C for and analyzed for E. coli O157:H7 populations for up to 7 d. Immersion of lettuce in 9.8 log PFU/ml EcoShield™ for 2 min significantly (p < 0.05) reduced E. coli O157:H7 populations after 24 h when stored at 4°C compared with controls. Immersion of lettuce in suspensions containing high concentrations of EcoShield™ (9.8 log PFU/ml) resulted in the deposition of high concentrations (7.8 log log PFU/cm2) of bacteriophages on the surface of fresh cut lettuce, potentially contributing to the efficacy of the lytic phages on lettuce. Spraying phages on to inoculated fresh cut lettuce after being washed in hypochlorite solution was significantly more effective in reducing E. coli O157:H7 populations (2.22 log CFU/cm2) on day 0 compared with control treatments (4.10 log CFU/cm2). Both immersion and spray treatments provided protection from E. coli O157:H7 contamination on lettuce, but spray application of lytic bacteriophages to lettuce was more effective in immediately reducing E. coli O157:H7 populations fresh cut lettuce. PMID:23819106

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

    PubMed Central

    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-guanylyltransferase; the cobS gene, encoding cobalamin synthetase; and the cobT gene, encoding dimethylbenzimidazole phosphoribosyltransferase. The physiological roles of these sequences were verified by the isolation of Tn10 insertion mutations in the cobS and cobT genes. All genes were named after their Salmonella typhimurium homologs and are located at the corresponding positions on the E. coli genetic map. Although the nucleotide sequences of the Salmonella cob genes and the E. coli cob genes are homologous, they are too divergent to have been derived from an operon present in their most recent common ancestor. On the basis of comparisons of G+C content, codon usage bias, dinucleotide frequencies, and patterns of synonymous and nonsynonymous substitutions, we conclude that the cob operon was introduced into the Salmonella genome from an exogenous source. The cob operon of E. coli may be related to cobalamin synthetic genes now found among non-Salmonella enteric bacteria. PMID:7592411

  4. An Escherichia coli Mutant That Makes Exceptionally Long Cells

    PubMed Central

    Newman, Elaine B.

    2015-01-01

    ABSTRACT Although Escherichia coli is a very small (1- to 2-μm) rod-shaped cell, here we describe an E. coli mutant that forms enormously long cells in rich media such as Luria broth, as long indeed as 750 μm. These extremely elongated (eel) cells are as long as the longest bacteria known and have no internal subdivisions. They are metabolically competent, elongate rapidly, synthesize DNA, and distribute cell contents along this length. They lack only the ability to divide. The concentration of the essential cell division protein FtsZ is reduced in these eel cells, and increasing this concentration restores division. IMPORTANCE Escherichia coli is usually a very small bacterium, 1 to 2 μm long. We have isolated a mutant that forms enormously long cells, 700 times longer than the usual E. coli cell. E. coli filaments that form under other conditions usually die within a few hours, whereas our mutant is fully viable even when it reaches such lengths. This mutant provides a useful tool for the study of aspects of E. coli physiology that are difficult to investigate with small cells. PMID:25691528

  5. Genomic Comparative Study of Bovine Mastitis Escherichia coli

    PubMed Central

    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 is a bias in the distribution of mastitis isolates in the different phylogenetic groups of the E. coli species, with the majority of strains belonging to phylogenetic groups A and B1. An interesting feature is that clustering of strains based on their accessory genome is very similar to that obtained using the core genome. This finding illustrates the fact that phenotypic properties of strains from different phylogroups are likely to be different. As a consequence, it is possible that different strategies could be used by mastitis isolates of different phylogroups to trigger mastitis. Our results indicate that mastitis E. coli isolates analyzed in this study carry very few of the virulence genes described in other pathogenic E. coli strains. A more detailed analysis of the presence/absence of genes involved in LPS synthesis, iron acquisition and type 6 secretion systems did not uncover specific properties of mastitis isolates. Altogether, these results indicate that mastitis E. coli isolates are rather characterized by a lack of bona fide currently described virulence genes. PMID:26809117

  6. The different ecological niches of enterotoxigenic Escherichia coli.

    PubMed

    Gonzales-Siles, Lucia; Sjöling, Åsa

    2016-03-01

    Enterotoxigenic Escherichia coli (ETEC) is a water and food-borne pathogen that infects the small intestine of the human gut and causes diarrhoea. Enterotoxigenic E. coli adheres to the epithelium by means of colonization factors and secretes two enterotoxins, the heat labile toxin and/or the heat stable toxin that both deregulate ion channels and cause secretory diarrhoea. Enterotoxigenic E. coli as all E. coli, is a versatile organism able to survive and grow in different environments. During transmission and infection, ETEC is exposed to various environmental cues that have an impact on survivability and virulence. The ability to cope with exposure to different stressful habitats is probably shaping the pool of virulent ETEC strains that cause both endemic and epidemic infections. This review will focus on the ecology of ETEC in its different habitats and interactions with other organisms as well as abiotic factors. PMID:26522129

  7. Enteropathogenic Escherichia coli in raw and cooked food.

    PubMed

    Norazah, A; Rahizan, I; Zainuldin, T; Rohani, M Y; Kamel, A G

    1998-03-01

    A total of 402 Escherichia coli isolates were obtained from a variety of food samples and screened for enteropathogenic E. coli (EPEC). Screening was carried out using 15 specific monovalent antisera from Murex Diagnostic Limited. A total of 19 E. coli isolates were serotyped as EPEC. The EPEC strains were shown to belong to 8 serotypes. Eight out of 19 EPEC strains belonged to serotype 018C:K77 (B21). Seventeen out of 19 of the EPEC strains were isolated from cooked food. The presence of E. coli in cooked food is an indicator of fecal contamination and a sign of unhygienic food handling. The presence of EPEC in food could be a potential source of food-borne outbreak. Hygiene training for every food-handler is a necessity. PMID:9740276

  8. Compilation of DNA sequences of Escherichia coli

    PubMed Central

    Kröger, Manfred

    1989-01-01

    We have compiled the DNA sequence data for E.coli K12 available from the GENBANK and EMBO databases and over a period of several years independently from the literature. We have introduced all available genetic map data and have arranged the sequences accordingly. As far as possible the overlaps are deleted and a total of 940,449 individual bp is found to be determined till the beginning of 1989. This corresponds to a total of 19.92% of the entire E.coli chromosome consisting of about 4,720 kbp. This number may actually be higher by some extra 2% derived from the sequence of lysogenic bacteriophage lambda and the various insertion sequences. This compilation may be available in machine readable form from one of the international databanks in some future. PMID:2654890

  9. Enteropathogenic Escherichia coli Prevalence in Laboratory Rabbits

    PubMed Central

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

    2013-01-01

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

  10. Resistance and virulence factors of Escherichia coli isolated from chicken.

    PubMed

    Pavlickova, Silvie; Dolezalova, Magda; Holko, Ivan

    2015-01-01

    Chicken meat has become an important part of the human diet and besides contamination by pathogenic Escherichia coli there is a risk of antibiotic resistance spreading via the food chain. The purpose of this study was to examine the prevalence of resistance against eight antibiotics and the presence of 14 virulence factors among 75 Escherichia coli strains isolated from chicken meat in the Czech Republic after classification into phylogenetic groups by the multiplex PCR method. More than half of strains belonged to A phylogroup, next frequently represented was B1 phylogroup, which suggests the commensal strains. The other strains were classified into phylogroups B2 and D, which had more virulence factors. Almost half of all E. coli strains were resistant to at least one of eight-tested antibiotics. A multidrug resistance was observed in 13% of strains. The most prevalent virulence genes were iucD, iss and tsh. None of genes encoding toxins was detected. Most of E. coli strains isolated from chicken meat can be considered as nonpathogenic on the basis of analysis of virulence factors, antibiotic resistance and phylogroups assignment. It can provide a useful tool for prediction of a potential risk from food contaminated by E. coli. PMID:25844863