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Sample records for live escherchia coli

  1. Escherchia coli ribose binding protein based bioreporters revisited

    PubMed Central

    Reimer, Artur; Yagur-Kroll, Sharon; Belkin, Shimshon; Roy, Shantanu; van der Meer, Jan Roelof

    2014-01-01

    Bioreporter bacteria, i.e., strains engineered to respond to chemical exposure by production of reporter proteins, have attracted wide interest because of their potential to offer cheap and simple alternative analytics for specified compounds or conditions. Bioreporter construction has mostly exploited the natural variation of sensory proteins, but it has been proposed that computational design of new substrate binding properties could lead to completely novel detection specificities at very low affinities. Here we reconstruct a bioreporter system based on the native Escherichia coli ribose binding protein RbsB and one of its computationally designed variants, reported to be capable of binding 2,4,6-trinitrotoluene (TNT). Our results show in vivo reporter induction at 50 nM ribose, and a 125 nM affinity constant for in vitro ribose binding to RbsB. In contrast, the purified published TNT-binding variant did not bind TNT nor did TNT cause induction of the E. coli reporter system. PMID:25005019

  2. Enhanced host immune recognition of mastitis causing Escherchia coli in CD-14 transgenic mice.

    PubMed

    Wall, R; Powell, A; Sohn, E; Foster-Frey, J; Bannerman, D; Paape, M

    2009-01-01

    Escherchia coli causes mastitis, an economically significant disease in dairy animals. E. coli endotoxin (lipopolysaccharide, LPS) when bound by host membrane proteins such as CD-14, causes release of proinflammatory cytokines recruiting neutrophils as an early, innate immune response. Excessive proinflammatory cytokines causes tissue damage, compromising mammary function. If present, soluble CD-14 (sCD-14) might out compete membrane bound CD-14, lessening the severity of the inflammatory response. To test this hypothesis transgenic mice, expressing sCD-14 in their milk (31 to 316 microg/ml), were evaluated. A cell culture study demonstrated, in the presence of LPS, milk from transgenic mice increased secretion of cytokine IL-8 compared to milk from nontransgenic littermates (18 +/- 3 vs. 35 +/- 2 ng/mL, p < 0.001). To assess protection afforded by the transgene, glands were infused with E. coli. Recovery of bacteria showed no clear relationship between sCD14 concentration and the number of organisms recovered; however, there was a strong relationship between sCD14 concentration and edema (r(2) = 0.999, p < 0.001), as measured by weight of fluid in harvested glands. Highest expressing lines had the least edema, suggesting the presence of sCD14 had an effect on reducing the inflammatory response to E. coli, thus, possibly protecting against gland tissue damage.

  3. The escherchia coli hemL gene encodes glutamate 1-semialdehyde aminotransferase

    SciTech Connect

    Ilag, L.L.; Jahn, D.; Soell, D. ); Eggertsson, G. )

    1991-06-01

    [sigma]-Aminolevulinic acid (ALA), the first committed precursor of porphyrin biosynthesis, is formed in Escherichia coli by the C[sub 5] pathway in a three-step, tRNA-dependent transformation from glutamate. The first two enzymes of this pathway, glutamyl-tRNA synthetase and Glu-tRNA reductase, are known in E. coli. Here we present the mapping and cloning of the gene for the third enzyme, glutamate 1-semialdehyde (GSA) aminotransferase, and an initial characterization of the purified enzyme, Ethylmethane sulfonate-induced mutants of E. coli AB354 which required ALA for growth were isolated by selection for respiration-defective strains resistent to the aminoglycoside antibiotic kanamycin. Two mutations were mapped to min 4 at a locus named hemL. Map positions and resulting phenotypes suggest that hemL may be identical with the earlier described porphyrin biosynthesis mutation popC. Complementation of the auxotrophic phenotype by wild-type DNA from the corresponding clone pLC4-43 of the Clarke-Carbon bank allowed the isolation of the gene. Physical mapping showed that hemL mapped clockwise next to fhuB. The hemL gene product was overexpressed and purified to apparent homogeneity. The pure protein efficiently converted GSA to ALA. The reaction was stimulated by the addition of pyridoxal 5[prime]-phosphate or pyridoxamine 5[prime]-phosphate and inhibited by gabaculine or aminooxyacetic acid. The molecular mass of the purified GSA aminotransferase under denaturing conditions was 40,000 Da, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The enzyme has an apparent native molecular mass of approximately 80,000 Da, as determined by rate zonal sedimentation on glycerol gradients and molecular sieving through Superose 12, which indicates a homodimeric [alpha][sub 2] structure of the protein.

  4. PHYSIOLOGICAL RESPONSES TO LIVE E. COLI ORGANISMS

    DTIC Science & Technology

    shock and shock produced by injection of live E . coli organisms in dogs. A primary purpose of our research has been to determine the effects of...intravenous injections of living E . coli organisms in dogs and monkeys and compare them with responses produced by endotoxin. Hemodynamic changes...pathologic alterations, and metabolic abnormalities have been evaluated in animals receiving lethal and sublethal injections of live E . coli organisms and comparable dosages of purified endotoxin.

  5. Asymptomatic Bacteriuria Escherichia coli Are Live Biotherapeutics for UTI

    PubMed Central

    Yaggie, Ryan E.; Schaeffer, Anthony J.; Klumpp, David J.

    2014-01-01

    Urinary tract infections (UTI) account for approximately 8 million clinic visits annually with symptoms that include acute pelvic pain, dysuria, and irritative voiding. Empiric UTI management with antimicrobials is complicated by increasing antimicrobial resistance among uropathogens, but live biotherapeutics products (LBPs), such as asymptomatic bacteriuria (ASB) strains of E. coli, offer the potential to circumvent antimicrobial resistance. Here we evaluated ASB E. coli as LBPs, relative to ciprofloxacin, for efficacy against infection and visceral pain in a murine UTI model. Visceral pain was quantified as tactile allodynia of the pelvic region in response to mechanical stimulation with von Frey filaments. Whereas ciprofloxacin promoted clearance of uropathogenic E. coli (UPEC), it did not reduce pelvic tactile allodynia, a measure of visceral pain. In contrast, ASB E. coli administered intravesically or intravaginally provided comparable reduction of allodynia similar to intravesical lidocaine. Moreover, ASB E. coli were similarly effective against UTI allodynia induced by Proteus mirabilis, Enterococccus faecalis and Klebsiella pneumoniae. Therefore, ASB E. coli have anti-infective activity comparable to the current standard of care yet also provide superior analgesia. These studies suggest that ASB E. coli represent novel LBPs for UTI symptoms. PMID:25405579

  6. Collective THz dynamics in living Escherichia coli cells

    NASA Astrophysics Data System (ADS)

    Sebastiani, F.; Orecchini, A.; Paciaroni, A.; Jasnin, M.; Zaccai, G.; Moulin, M.; Haertlein, M.; De Francesco, A.; Petrillo, C.; Sacchetti, F.

    2013-10-01

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

  7. Enhanced host immune recognition of E.coli causing mastitis in CD-14 transgenic mice.

    USDA-ARS?s Scientific Manuscript database

    Escherchia coli causes mastitis, an economically significant disease in dairy animals. E. coli endotoxin (lipopolysaccharide, LPS) when bound by host membrane proteins such as CD-14, causes release of pro-inflammatory cytokines recruiting neutrophils as a early innate immune response. Excessive pr...

  8. CARDIORESPIRATORY AND METABOLIC RESPONSES TO LIVE E. COLI AND ENDOTOXIN IN THE MONKEY

    DTIC Science & Technology

    of live organisms (Escherichia coli) were compared with endotoxin and saline in rhesus monkeys. Six animals were given E . coli , six endotoxin, and...five served as controls. Studies were conducted for 2-4 hours. The mean cardiac output decreased 62% within 60-90 minutes in the E . coli group and 41...Pco2 decreased to 24 mm Hg in the E . coli group and 26 mm Hg in the endotoxin group. Arterial hypoxemia developed in four animals and high

  9. Effects of Anti-Inflammatory Drugs in Shock Caused by Injection of Living E. Coli Cells

    DTIC Science & Technology

    Injection of live E . coli organisms to dogs iv causes a lethal shock. Administrations of anti-inflammatory drugs (indomethacin, aminopyrine...the injection of E . coli were significantly different in the treated animals from those in the control group. Some of the other agents tested were

  10. Detection and Classification of Live and Dead Escherichia coli by Laser-Induced Breakdown Spectroscopy

    PubMed Central

    Sivakumar, P.; Fernández-Bravo, A.; Taleh, L.; Biddle, J.F.

    2015-01-01

    Abstract A common goal for astrobiology is to detect organic materials that may indicate the presence of life. However, organic materials alone may not be representative of currently living systems. Thus, it would be valuable to have a method with which to determine the health of living materials. Here, we present progress toward this goal by reporting on the application of laser-induced breakdown spectroscopy (LIBS) to study characteristics of live and dead cells using Escherichia coli (E. coli) strain K12 cells as a model organism since its growth and death in the laboratory are well understood. Our goal is to determine whether LIBS, in its femto- and/or nanosecond forms, could ascertain the state of a living organism. E. coli strain K12 cells were grown, collected, and exposed to one of two types of inactivation treatments: autoclaving and sonication. Cells were also kept alive as a control. We found that LIBS yields key information that allows for the discrimination of live and dead E. coli bacteria based on ionic shifts reflective of cell membrane integrity. Key Words: E. coli—Trace elements—Live and dead cells—Laser-induced breakdown spectroscopy—Atomic force microscopy. Astrobiology 15, 144–153. PMID:25683088

  11. Detection and classification of live and dead Escherichia coli by laser-induced breakdown spectroscopy.

    PubMed

    Sivakumar, P; Fernández-Bravo, A; Taleh, L; Biddle, J F; Melikechi, N

    2015-02-01

    A common goal for astrobiology is to detect organic materials that may indicate the presence of life. However, organic materials alone may not be representative of currently living systems. Thus, it would be valuable to have a method with which to determine the health of living materials. Here, we present progress toward this goal by reporting on the application of laser-induced breakdown spectroscopy (LIBS) to study characteristics of live and dead cells using Escherichia coli (E. coli) strain K12 cells as a model organism since its growth and death in the laboratory are well understood. Our goal is to determine whether LIBS, in its femto- and/or nanosecond forms, could ascertain the state of a living organism. E. coli strain K12 cells were grown, collected, and exposed to one of two types of inactivation treatments: autoclaving and sonication. Cells were also kept alive as a control. We found that LIBS yields key information that allows for the discrimination of live and dead E. coli bacteria based on ionic shifts reflective of cell membrane integrity.

  12. Dissecting the stochastic transcription initiation process in live Escherichia coli.

    PubMed

    Lloyd-Price, Jason; Startceva, Sofia; Kandavalli, Vinodh; Chandraseelan, Jerome G; Goncalves, Nadia; Oliveira, Samuel M D; Häkkinen, Antti; Ribeiro, Andre S

    2016-06-01

    We investigate the hypothesis that, in Escherichia coli, while the concentration of RNA polymerases differs in different growth conditions, the fraction of RNA polymerases free for transcription remains approximately constant within a certain range of these conditions. After establishing this, we apply a standard model-fitting procedure to fully characterize the in vivo kinetics of the rate-limiting steps in transcription initiation of the Plac/ara-1 promoter from distributions of intervals between transcription events in cells with different RNA polymerase concentrations. We find that, under full induction, the closed complex lasts ∼788 s while subsequent steps last ∼193 s, on average. We then establish that the closed complex formation usually occurs multiple times prior to each successful initiation event. Furthermore, the promoter intermittently switches to an inactive state that, on average, lasts ∼87 s. This is shown to arise from the intermittent repression of the promoter by LacI. The methods employed here should be of use to resolve the rate-limiting steps governing the in vivo dynamics of initiation of prokaryotic promoters, similar to established steady-state assays to resolve the in vitro dynamics. © The Author 2016. Published by Oxford University Press on behalf of Kazusa DNA Research Institute.

  13. Dissecting the stochastic transcription initiation process in live Escherichia coli

    PubMed Central

    Lloyd-Price, Jason; Startceva, Sofia; Kandavalli, Vinodh; Chandraseelan, Jerome G.; Goncalves, Nadia; Oliveira, Samuel M. D.; Häkkinen, Antti; Ribeiro, Andre S.

    2016-01-01

    We investigate the hypothesis that, in Escherichia coli, while the concentration of RNA polymerases differs in different growth conditions, the fraction of RNA polymerases free for transcription remains approximately constant within a certain range of these conditions. After establishing this, we apply a standard model-fitting procedure to fully characterize the in vivo kinetics of the rate-limiting steps in transcription initiation of the Plac/ara-1 promoter from distributions of intervals between transcription events in cells with different RNA polymerase concentrations. We find that, under full induction, the closed complex lasts ∼788 s while subsequent steps last ∼193 s, on average. We then establish that the closed complex formation usually occurs multiple times prior to each successful initiation event. Furthermore, the promoter intermittently switches to an inactive state that, on average, lasts ∼87 s. This is shown to arise from the intermittent repression of the promoter by LacI. The methods employed here should be of use to resolve the rate-limiting steps governing the in vivo dynamics of initiation of prokaryotic promoters, similar to established steady-state assays to resolve the in vitro dynamics. PMID:27026687

  14. Encapsulation of living E. coli cells in hollow polymer microspheres of highly defined size.

    PubMed

    Flemke, Jennifer; Maywald, Matthias; Sieber, Volker

    2013-01-14

    Here, we report the preparation and characterization of hollow polymer microspheres based on the preprecipitation of porous calcium carbonate cores with an average size of 5 μm and their use for encapsulation of living microorganisms. The microspheres filled with individual living E. coli cells were prepared by layer-by-layer (LbL) deposition of different polyelectrolytes and proteins onto the porous calcium carbonate cores leading to the formation of matrix-like complexes of the compounds followed by calcium carbonate core dissolution using EDTA. Both the influence of the encapsulation process as well as of the used polyelectrolytes on the survival rate of the cells were determined by confocal laser scanning microscopy (CLSM) and microtiter plate fluorescence tests. After the encapsulation process ~40% of the cells were alive. Cultivation tests indicated that the lag phase of cells treated with polyelectrolytes increases and the encapsulated E. coli cells were able to produce green fluorescent protein inside the microcapsules.

  15. Genotype Analysis of Escherichia coli Strains Isolated from Children and Chickens Living in Close Contact

    PubMed Central

    Kariuki, S.; Gilks, C.; Kimari, J.; Obanda, A.; Muyodi, J.; Waiyaki, P.; Hart, C. A.

    1999-01-01

    Escherichia coli isolates from rectal swabs from 62 chickens and stools from 42 children living in close contact with chickens on the same farms in Kiambu district, Kenya, were compared for their genetic relatedness. Antibiotic susceptibility profiles broadly categorized isolates from the children and from the chickens into two separate clusters: the majority (144; 85.5%) of the E. coli isolates from children were multidrug resistant, while the majority (216; 87.1%) of the E. coli isolates from chickens were either fully susceptible or resistant only to tetracycline. Sixty- and 100- to 110-MDA plasmids were found to encode the transferable resistance to co-trimoxazole and tetracycline. HindIII restriction endonuclease digestion of the 60- and 100- to 110-MDA plasmids produced four distinct patterns for isolates from children and three distinct patterns for isolates from chickens. XbaI digestion of genomic DNA followed by pulsed-field gel electrophoresis (PFGE) analysis produced 14 distinct clusters. There were six distinct PFGE clusters among the isolates from children, while among the isolates from chickens there were seven distinct clusters. Only one PFGE cluster contained isolates from both children and chickens, with the isolates displaying an approximately 60% coefficient of similarity. This study showed that although several different genotypes of E. coli were isolated from children and chickens from the same farms, the E. coli strains from these two sources were distinct. PMID:9925570

  16. RECOVERY PATTERNS AND LETHAL MANIFESTATIONS OF LIVE E. COLI ORGANISM SHOCK

    DTIC Science & Technology

    The purpose of the present study was to develop a more clinically applicable animal shock model by withholding anesthetics while administering live E . coli organisms at a dosage producing the degree of lethality seen in clinical medicine and to study the animals in an unrestrained condition during a substantially extended post-shock period. Results from these experiments are thought to be of promise in regard to more closely approximating the manifestations of clinical shock in man.

  17. Effects of Methylprednisolone Sodium Succinate on Clearance of Live E. coli from the Peripheral Blood of Dogs.

    DTIC Science & Technology

    1978-08-28

    live E . coli organisms from peripheral blood of dogs. The experimental group was pretreated with 30 mg/kg of MP while controls received equal volumes...of saline. Both control and MP pretreated dogs significantly reduced the number of E . coli in peripheral blood by almost two orders of magnitude...however, there was no significant difference in clearance of E . coli organisms between the two groups. An initial leukopenia occured in both groups after

  18. Single-Molecule Specific Mislocalization of Red Fluorescent Proteins in Live Escherichia coli.

    PubMed

    Ghodke, Harshad; Caldas, Victor E A; Punter, Christiaan M; van Oijen, Antoine M; Robinson, Andrew

    2016-07-12

    Tagging of individual proteins with genetically encoded fluorescent proteins (FPs) has been used extensively to study localization and interactions in live cells. Recent developments in single-molecule localization microscopy have enabled the dynamic visualization of individual tagged proteins inside living cells. However, tagging proteins with FPs is not without problems: formation of insoluble aggregates and inhibition of native functions of the protein are well-known issues. Previously reported artifacts manifest themselves at all expression levels of the FP-tagged proteins, making the design of control experiments relatively straightforward. Here, we describe a previously uncharacterized mislocalization artifact of Entacmaea quadricolor red fluorescent protein variants that is detectable at the single-molecule level in live Escherichia coli cells. Copyright © 2016 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  19. Survival characteristics of diarrheagenic Escherichia coli pathotypes and Helicobacter pylori during passage through the free-living ciliate, Tetrahymena sp.

    PubMed

    Smith, Charlotte D; Berk, Sharon G; Brandl, Maria T; Riley, Lee W

    2012-12-01

    Free-living protozoa have been implicated in the survival and transport of pathogens in the environment, but the relationship between non-Shiga toxin-producing Escherichia coli or Helicobacter pylori and ciliates has not been characterized. Six diarrheagenic pathotypes of E. coli and an isolate of H. pylori were evaluated for their susceptibility to digestion by Tetrahymena, an aquatic ciliate. Tetrahymena strain MB125 was fed E. coli or H. pylori, and the ciliate's egested products examined for viable bacterial pathogens by the BacLight(™) LIVE/DEAD (™) assay, a cell elongation method, and by colony counts. All six diarrheagenic E. coli pathotypes survived digestion, whereas H. pylori was digested. Growth of E. coli on agar plates indicated that the bacteria were able to replicate after passage through the ciliate. Transmission electron micrographs of E. coli cells as intact rods vs. degraded H. pylori cells corroborated these results. Scanning electron microscopy revealed a net-like matrix around intact E. coli cells in fecal pellets. These results suggest a possible role for Tetrahymena and its egested fecal pellets in the dissemination of diarrheagenic E. coli in the environment. This bacterial-protozoan interaction may increase opportunities for transmission of diarrheagenic E. coli to mammalian hosts including humans. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  20. Luminescence Resonance Energy Transfer in the Cytoplasm of Live Escherichia coli Cells

    PubMed Central

    González, Daniel; Lokhande, Nayanish; Vadde, Swaraj; Zhao, Qi; Cassill, Aaron; Renthal, Robert

    2011-01-01

    Luminescence resonance energy transfer (LRET) offers many advantages for accurate measurements of distances between specific sites in living cells, but progress in developing methodology for implementing this technique has been limited. We report here the design, expression, and characterization of a test protein for development of LRET methodology. The protein, which we call DAL, contains the following domains (from the N-terminus): E. coli dihydrofolate reductase (DHFR), the third and fourth ankyrin repeats of p16INK4a, a lanthanide-binding tag (LBT), and a hexahistidine tag. LBT binds Tb3+ with a sub-micromolar dissociation constant. LRET was measured from the Tb3+ site on LBT to transition metals bound to the hexa-His tag, and to fluorescein methotrexate bound to DHFR. The measured distances were consistent with a molecular model constructed from the known crystal structures of the constituent domains of DAL. The results indicate that the two C-terminal ankyrin domains of p16INK4a are stably folded when combined with other protein domains. We found that Tb3+ binds to DAL in the cytoplasm of live E. coli cells, and thus DAL is useful as an indicator for studies of metal transport. We also used DAL to measure LRET from Tb3+ to Cu2+ in the cytoplasm of live E. coli cells. The rates of Tb3+ and Cu2+ transport were not affected by a proton uncoupler or an ATP synthase inhibitor. Reversal of the membrane potential had a small inhibitory effect, and removal of lipopolysaccharide had a small accelerating affect on transport. Changing the external pH from 7 to 5 strongly inhibited the Tb3+ signal, suggesting that the Tb3+-LBT interaction is useful as a cytoplasmic pH indicator in the range of about pH 5-6. PMID:21739954

  1. Monitoring Dynamic Protein Expression in Single Living E. Coli. Bacterial Cells by Laser Tweezers Raman Spectroscopy

    SciTech Connect

    Chan, J W; Winhold, H; Corzett, M H; Ulloa, J M; Cosman, M; Balhorn, R; Huser, T

    2007-01-09

    Laser tweezers Raman spectroscopy (LTRS) is a novel, nondestructive, and label-free method that can be used to quantitatively measure changes in cellular activity in single living cells. Here, we demonstrate its use to monitor changes in a population of E. coli cells that occur during overexpression of a protein, the extracellular domain of myelin oligodendrocyte glycoprotein (MOG(1-120)) Raman spectra were acquired of individual E. coli cells suspended in solution and trapped by a single tightly focused laser beam. Overexpression of MOG(1-120) in transformed E. coli Rosetta-Gami (DE3)pLysS cells was induced by addition of isopropyl thiogalactoside (IPTG). Changes in the peak intensities of the Raman spectra from a population of cells were monitored and analyzed over a total duration of three hours. Data was also collected for concentrated purified MOG(1-120) protein in solution, and the spectra compared with that obtained for the MOG(1-120) expressing cells. Raman spectra of individual, living E. coli cells exhibit signatures due to DNA and protein molecular vibrations. Characteristic Raman markers associated with protein vibrations, such as 1257 cm{sup -1}, 1340 cm{sup -1}, 1453 cm{sup -1} and 1660 cm{sup -1}, are shown to increase as a function of time following the addition of IPTG. Comparison of these spectra and the spectra of purified MOG protein indicates that the changes are predominantly due to the induction of MOG protein expression. Protein expression was found to occur mostly within the second hour, with a 470% increase relative to the protein expressed in the first hour. A 230% relative increase between the second and third hour indicates that protein expression begins to level off within the third hour. It is demonstrated that LTRS has sufficient sensitivity for real-time, nondestructive, and quantitative monitoring of biological processes, such as protein expression, in single living cells. Such capabilities, which are not currently available in

  2. A model for chromosome organization during the cell cycle in live E. coli

    PubMed Central

    Liu, Yuru; Xie, Ping; Wang, Pengye; Li, Ming; Li, Hui; Li, Wei; Dou, Shuoxing

    2015-01-01

    Bacterial chromosomal DNA is a highly compact nucleoid. The organization of this nucleoid is poorly understood due to limitations in the methods used to monitor the complexities of DNA organization in live bacteria. Here, we report that circular plasmid DNA is auto-packaged into a uniform dual-toroidal-spool conformation in response to mechanical stress stemming from sharp bending and un-winding by atomic force microscopic analysis. The mechanism underlying this phenomenon was deduced with basic physical principles to explain the auto-packaging behaviour of circular DNA. Based on our observations and previous studies, we propose a dynamic model of how chromosomal DNA in E. coli may be organized during a cell division cycle. Next, we test the model by monitoring the development of HNS clusters in live E. coli during a cell cycle. The results were in close agreement with the model. Furthermore, the model accommodates a majority of the thus-far-discovered remarkable features of nucleoids in vivo. PMID:26597953

  3. Genotypic and phenotypic analysis of diarrheagenic Escherichia coli strains isolated from Brazilian children living in low socioeconomic level communities

    PubMed Central

    2013-01-01

    Background Childhood diarrheal diseases remain highly endemic in developing areas of Brazil. The importance of Escherichia coli among children with diarrhea in these areas was unknown. This study determined the prevalence of different E. coli categories in symptomatic and asymptomatic children from low socioeconomic level rural communities in southeastern Brazil. Methods A total of 560 stool samples were collected from 141 children with diarrhea (< 10 years) and 419 apparently healthy controls who resided in 23 communities. E. coli isolates (n = 1943) were subjected to two multiplex PCRs developed for the detection of enteropathogenic E. coli (EPEC), enteroaggregative E. coli (EAEC), diffusely adherent E. coli (DAEC), enterotoxigenic E. coli (ETEC), enteroinvasive E. coli (EIEC), and Shiga toxin-producing E. coli (STEC). Strains were also examined for the presence of EPEC, EAEC, and DAEC by assays of adhesion to HEp-2 cells and by hybridization with specific DNA probes. Results Diarrheagenic E. coli strains were isolated from 253 (45.2%) children, and were associated with diarrhea in children aged < 5 years (p < 0.001). EAEC (20.9%), DAEC (11.6%), EPEC (9.3%) were the most frequent pathotypes, followed by ETEC (2.7%), EIEC (0.5%), and STEC (0.2%). Depending of the assay, EPEC, EAEC, and DAEC (collectively termed enteroadherent E. coli) strains were isolated in 45% to 56% of diarrhea cases, a significantly higher incidence than in controls (P < 0.05). Individually, only DAEC showed significant association with diarrhea (p < 0.05), particularly in children aged 2–5 years. Conclusion This study indicates that enteroadherent E. coli is an important cause of diarrhea in children living in low socioeconomic level communities in southeastern Brazil. Our results reveal that the PCR1 assay is an excellent tool for the identification of EAEC and DAEC. PMID:24010735

  4. Captive and free-living urban pigeons (Columba livia) from Brazil as carriers of multidrug-resistant pathogenic Escherichia coli.

    PubMed

    Borges, Clarissa A; Maluta, Renato P; Beraldo, Lívia G; Cardozo, Marita V; Guastalli, Elisabete A L; Kariyawasam, Subhashinie; DebRoy, Chitrita; Ávila, Fernando A

    2017-01-01

    Thirty Escherichia coli isolates from captive and free-living pigeons in Brazil were characterised. Virulence-associated genes identified in pigeons included those which occur relatively frequently in avian pathogenic E. coli (APEC) from commercial poultry worldwide. Eleven of 30 E. coli isolates from pigeons, belonging mainly to B1 and B2 phylogenetic groups, had high or intermediate pathogenicity for 1-day-old chicks. The frequency of multi-drug resistant (MDR) E. coli in captive pigeons was relatively high and included one isolate positive for the extended-spectrum β-lactamase (ESBL) gene blaCTX-M-8. Pulsed field gel electrophoresis (PFGE) showed high heterogeneity among isolates. There is potential for pigeons to transmit antibiotic resistant pathogenic E. coli to other species through environmental contamination or direct contact. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Superresolution Imaging of Ribosomes and RNA Polymerase in Live Escherichia coli Cells

    PubMed Central

    Bakshi, Somenath; Siryaporn, Albert; Goulian, Mark; Weisshaar, James C.

    2012-01-01

    Summary Quantitative spatial distributions of ribosomes (S2-YFP) and RNA polymerase (β′-yGFP) in live E. coli are measured by superresolution fluorescence microscopy. In moderate growth conditions, Nucleoid-ribosome segregation is strong, and RNAP localizes to the nucleoid lobes. The mean copy numbers per cell are 4600 RNAPs and 55,000 ribosomes. Only 10–15% of the ribosomes lie within the densest part of the nucleoid lobes, and at most 4% of the RNAPs lie in the two ribosome-rich endcaps. The predominant observed diffusion coefficient of ribosomes is Dribo = 0.04 μm2/s, attributed to free mRNA being translated by one or more 70S ribosomes. We find no clear evidence of sub-diffusion, as would arise from tethering of ribosomes. The degree of DNA-ribosome segregation strongly suggests that in E. coli most translation occurs on free mRNA transcripts that have diffused into the ribosome-rich regions. Both RNAP and ribosome radial distributions extend to the cytoplasmic membrane, consistent with the transertion hypothesis. However, few if any RNAP copies lie near the membrane of the endcaps. This suggests that if transertion occurs, it exerts a direct radially expanding force on the nucleoid, but not a direct axially expanding force. PMID:22624875

  6. Single-molecule imaging of electroporated dye-labelled CheY in live Escherichia coli

    PubMed Central

    Di Paolo, Diana; Afanzar, Oshri; Armitage, Judith P.; Berry, Richard M.

    2016-01-01

    For the past two decades, the use of genetically fused fluorescent proteins (FPs) has greatly contributed to the study of chemotactic signalling in Escherichia coli including the activation of the response regulator protein CheY and its interaction with the flagellar motor. However, this approach suffers from a number of limitations, both biological and biophysical: for example, not all fusions are fully functional when fused to a bulky FP, which can have a similar molecular weight to its fused counterpart; they may interfere with the native interactions of the protein and the chromophores of FPs have low brightness and photostability and fast photobleaching rates. A recently developed technique for the electroporation of fluorescently labelled proteins in live bacteria has enabled us to bypass these limitations and study the in vivo behaviour of CheY at the single-molecule level. Here we show that purified CheY proteins labelled with organic dyes can be internalized into E. coli cells in controllable concentrations and imaged with video fluorescence microscopy. The use of this approach is illustrated by showing single CheY molecules diffusing within cells and interacting with the sensory clusters and the flagellar motors in real time. This article is part of the themed issue ‘The new bacteriology’. PMID:27672145

  7. Green biosynthesis of biocompatible CdSe quantum dots in living Escherichia coli cells

    NASA Astrophysics Data System (ADS)

    Yan, Zhengyu; Qian, Jing; Gu, Yueqing; Su, Yilong; Ai, Xiaoxia; Wu, Shengmei

    2014-03-01

    A green and efficient biosynthesis method to prepare fluorescence-tunable biocompatible cadmium selenide quantum dots using Escherichia coli cells as biological matrix was proposed. Decisive factors in biosynthesis of cadmium selenide quantum dots in a designed route in Escherichia coli cells were elaborately investigated, including the influence of the biological matrix growth stage, the working concentration of inorganic reactants, and the co-incubation duration of inorganic metals to biomatrix. Ultraviolet-visible, photoluminescence, and inverted fluorescence microscope analysis confirmed the unique optical properties of the biosynthesized cadmium selenide quantum dots. The size distribution of the nanocrystals extracted from cells and the location of nanocrystals foci in vivo were also detected seriously by transmission electron microscopy. A surface protein capping layer outside the nanocrystals was confirmed by Fourier transform infrared spectroscopy measurements, which were supposed to contribute to reducing cytotoxicity and maintain a high viability of cells when incubating with quantum dots at concentrations as high as 2 μM. Cell morphology observation indicated an effective labeling of living cells by the biosynthesized quantum dots after a 48 h co-incubation. The present work demonstrated an economical and environmentally friendly approach to fabricating highly fluorescent quantum dots which were expected to be an excellent fluorescent dye for broad bio-imaging and labeling.

  8. Superresolution imaging of ribosomes and RNA polymerase in live Escherichia coli cells.

    PubMed

    Bakshi, Somenath; Siryaporn, Albert; Goulian, Mark; Weisshaar, James C

    2012-07-01

    Quantitative spatial distributions of ribosomes (S2-YFP) and RNA polymerase (RNAP; β'-yGFP) in live Escherichia coli are measured by superresolution fluorescence microscopy. In moderate growth conditions, nucleoid-ribosome segregation is strong, and RNAP localizes to the nucleoid lobes. The mean copy numbers per cell are 4600 RNAPs and 55,000 ribosomes. Only 10-15% of the ribosomes lie within the densest part of the nucleoid lobes, and at most 4% of the RNAPs lie in the two ribosome-rich endcaps. The predominant observed diffusion coefficient of ribosomes is D(ribo) = 0.04 µm(2) s(-1), attributed to free mRNA being translated by one or more 70S ribosomes. We find no clear evidence of subdiffusion, as would arise from tethering of ribosomes to the DNA. The degree of DNA-ribosome segregation strongly suggests that in E. coli most translation occurs on free mRNA transcripts that have diffused into the ribosome-rich regions. Both RNAP and ribosome radial distributions extend to the cytoplasmic membrane, consistent with the transertion hypothesis. However, few if any RNAP copies lie near the membrane of the endcaps. This suggests that if transertion occurs, it exerts a direct radially expanding force on the nucleoid, but not a direct axially expanding force.

  9. Substrate-dependent assembly of the Tat translocase as observed in live Escherichia coli cells.

    PubMed

    Rose, Patrick; Fröbel, Julia; Graumann, Peter L; Müller, Matthias

    2013-01-01

    The twin-arginine translocation (Tat) pathway guides fully folded proteins across membranes of bacteria, archaea and plant chloroplasts. In Escherichia coli, Tat-specific transport is executed in a still largely unknown manner by three functionally diverse membrane proteins, termed TatA, TatB, and TatC. In order to follow the intracellular distribution of the TatABC proteins in live E. coli cells, we have individually expressed fluorophore-tagged versions of each Tat protein in addition to a set of chromosomally encoded TatABC proteins. In this way, a Tat translocase could form from the native TatABC proteins and be visualized via the association of a fluorescent Tat variant. A functionally active TatA-green fluorescent protein fusion was found to re-locate from a uniform distribution in the membrane into a few clusters preferentially located at the cell poles. Clustering was absolutely dependent on the co-expression of functional Tat substrates, the proton-motive force, and the cognate TatBC subunits. Likewise, polar cluster formation of a functional TatB-mCherry fusion required TatA and TatC and that of a functional TatC-mCherry fusion a functional Tat substrate. Furthermore we directly demonstrate the co-localization of TatA and TatB in the same fluorescent clusters. Our collective results are consistent with distinct Tat translocation sites dynamically forming in vivo in response to newly synthesized Tat substrates.

  10. Substrate-Dependent Assembly of the Tat Translocase as Observed in Live Escherichia coli Cells

    PubMed Central

    Rose, Patrick; Fröbel, Julia; Graumann, Peter L.; Müller, Matthias

    2013-01-01

    The twin-arginine translocation (Tat) pathway guides fully folded proteins across membranes of bacteria, archaea and plant chloroplasts. In Escherichia coli, Tat-specific transport is executed in a still largely unknown manner by three functionally diverse membrane proteins, termed TatA, TatB, and TatC. In order to follow the intracellular distribution of the TatABC proteins in live E. coli cells, we have individually expressed fluorophore-tagged versions of each Tat protein in addition to a set of chromosomally encoded TatABC proteins. In this way, a Tat translocase could form from the native TatABC proteins and be visualized via the association of a fluorescent Tat variant. A functionally active TatA-green fluorescent protein fusion was found to re-locate from a uniform distribution in the membrane into a few clusters preferentially located at the cell poles. Clustering was absolutely dependent on the co-expression of functional Tat substrates, the proton-motive force, and the cognate TatBC subunits. Likewise, polar cluster formation of a functional TatB-mCherry fusion required TatA and TatC and that of a functional TatC-mCherry fusion a functional Tat substrate. Furthermore we directly demonstrate the co-localization of TatA and TatB in the same fluorescent clusters. Our collective results are consistent with distinct Tat translocation sites dynamically forming in vivo in response to newly synthesized Tat substrates. PMID:23936332

  11. Diarrheagenic Escherichia coli pathotypes investigation revealed atypical enteropathogenic E. coli as putative emerging diarrheal agents in children living in Botucatu, São Paulo State, Brazil.

    PubMed

    Dias, Regiane C B; Dos Santos, Bruna C; Dos Santos, Luis F; Vieira, Melissa A; Yamatogi, Ricardo S; Mondelli, Alessandro L; Sadatsune, Terue; Sforcin, José M; Gomes, Tânia A T; Hernandes, Rodrigo T

    2016-04-01

    The aim of the present study was to investigate the prevalence of Diarrheagenic Escherichia coli (DEC) pathotypes, a leading cause of diarrhea worldwide, among diarrheal and healthy children, up to 5 years of age, living in the city of Botucatu, São Paulo, Brazil. DEC, investigated by PCR detection of virulence factor-encoding genes associated with the distinct pathotypes, was isolated from 18.0% of the patients, and 19.0% of the controls, with enteroaggregative E. coli (EAEC), the most frequent pathotype, being detected in equal proportion between patients and controls (10.0%). Among the enteropathogenic E. coli (EPEC) isolates, only one isolate was able to produce the localized adherence pattern to HeLa cells, being thus the only typical EPEC identified. All the remaining EPEC were classified as atypical (aEPEC), and detected in 8.0% and 8.5% of the patients and controls, respectively. Regarding the serotypes, 26.5% of the analyzed EPEC isolates belonged to classical EPEC-serogroups, and the only two STEC found were serotyped as O26:H11 (patient) and O119:H7 (control). Antimicrobial susceptibility tests revealed that 43.6%, 29.5% and 2.6% of the DEC isolates were resistant to ampicillin, cotrimoxazole and gentamicin, respectively. Our data indicate that EAEC remains prevalent among children living in Botucatu, and revealed atypical EPEC as emerging putative diarrheal agents in this geographical region. © 2016 APMIS. Published by John Wiley & Sons Ltd.

  12. Label-free identification of antibiotic resistant isolates of living Escherichia coli: Pilot study.

    PubMed

    Cheong, Youjin; Jin Kim, Young; Kang, Heeyoon; Choi, Samjin; Joo Lee, Hee

    2017-02-01

    We introduce a label-free spectroscopic method to classify subtypes of quinolone-nonsusceptible Escherichia coli (E. coli) isolates obtained from human blood cultures. Raman spectroscopy with a 30-nm gold-deposited, surface-enhanced Raman scattering (SERS) substrate was used to evaluate three multilocus sequencing typing (MLST)-predefined groups including E. coli ATCC25922, E. coli ST131:O75, and E. coli ST1193:O25b. Although there was a coffee-ring effect, the ring zone was selected at the ideal position to screen E. coli isolates. Strong Raman peaks were present at 1001-1004 cm(-1) (CC aromatic ring breathing stretching vibrational mode of phenylalanine), 1447-1448 cm(-1) (CH2 scissoring deformation vibrational mode), and 1667 cm(-1) (amide I α-helix). Although the three MLST-predefined E. coli isolates had similar Raman spectral patterns, a support vector machine (SVM) learning algorithm-assisted principal component analysis (PCA) analysis had superior performance in detecting the presence of quinolone-nonsusceptible E. coli isolates as well as classifying similar microbes, such as quinolone-nonsusceptible E. coli ST131:O75 and E. coli ST1193:O25b isolates. Therefore, this label-free and nondestructive technique is likely to be useful for clinically diagnosing quinolone-nonsusceptible E. coli isolates with the MLST method.

  13. Effects of dihydroergotamine on the feline cardiovascular response to intravenous infusion of live Escherichia coli bacteria.

    PubMed

    Arvidsson, S; Lindblad, B; Esquivel, C; Fält, K; Lindström, C; Bergqvist, D; Haglund, U

    1984-01-01

    A septic shock state was induced in cats by intravenous infusion of live Escherichia coli bacteria. Cats pretreated with an unspecific 5-HT blocker, dihydroergotamine (DHE), or with a specific 5-HT blocker, ketanserin, were compared with a series receiving bacteria without pretreatment. DHE pretreatment prevented the reduction in systemic arterial blood pressure found in the other series during the 2-hour period of septic shock. Pretreatment could not influence the increased vascular resistance in the pulmonary vascular bed or the early increase in pulmonary arterial blood pressure. Peripheral blood flow distribution was studied using radioactive labelled microspheres. Compared to bacteremia without pretreatment, the 5-HT blockers increased CNS blood flow and ketanserin also prevented the reduction in pancreatic blood flow. Gastric blood flow and gastric mucosal blood flow remained unchanged in all series as did the small intestinal total blood flow. Small intestinal mucosal blood flow, however, was reduced after 2 h of bacteremia. Microscopy revealed no gastric epithelial damage while the jejunal mucosa was characteristically damaged. There was no correlation between the changes in the small intestinal blood flow and the degree of mucosal damage, however, supporting the countercurrent theory for the pathogenesis of these lesions.

  14. Subdiffraction-Limit Study of Kaede Diffusion and Spatial Distribution in Live Escherichia coli

    PubMed Central

    Bakshi, Somenath; Bratton, Benjamin P.; Weisshaar, James C.

    2011-01-01

    Photoactivation localization microscopy (PALM) is used to study the spatial distribution and diffusion of single copies of the protein Kaede in the cytoplasm of live Escherichia coli under moderate growth conditions (67 min doubling time). The spatial distribution of Kaede is uniform within the cytoplasm. The cytoplasmic radius of 380 ± 30 nm varies little from cell to cell. Single-particle tracking using 4 ms exposure times reveals negatively curved plots of mean-square displacement versus time. A detailed comparison with Monte Carlo simulations in a spherocylindrical volume shows that the curvature can be quantitatively understood in terms of free diffusion within a confining volume. The mean diffusion coefficient across cells is  = 7.3 ± 1.1 μm2·s−1, consistent with a homotetrameric form of Kaede. The distribution of squared displacements along the long axis for individual Kaede molecules is consistent with homogeneous diffusion. However, for longer cells, a spatial map of one-step estimates of the diffusion coefficient along x suggests that diffusion is ∼20–40% faster within nucleoids than in the ribosome-rich region lying between nucleoid lobes at the cell mid-plane. Fluorescence recovery after photobleaching yielded  = 8.3 ± 1.6 μm2·s−1, in agreement with the single-particle tracking results. PMID:22098753

  15. Subdiffraction-limit study of Kaede diffusion and spatial distribution in live Escherichia coli.

    PubMed

    Bakshi, Somenath; Bratton, Benjamin P; Weisshaar, James C

    2011-11-16

    Photoactivation localization microscopy (PALM) is used to study the spatial distribution and diffusion of single copies of the protein Kaede in the cytoplasm of live Escherichia coli under moderate growth conditions (67 min doubling time). The spatial distribution of Kaede is uniform within the cytoplasm. The cytoplasmic radius of 380 ± 30 nm varies little from cell to cell. Single-particle tracking using 4 ms exposure times reveals negatively curved plots of mean-square displacement versus time. A detailed comparison with Monte Carlo simulations in a spherocylindrical volume shows that the curvature can be quantitatively understood in terms of free diffusion within a confining volume. The mean diffusion coefficient across cells is = 7.3 ± 1.1 μm(2)·s(-1), consistent with a homotetrameric form of Kaede. The distribution of squared displacements along the long axis for individual Kaede molecules is consistent with homogeneous diffusion. However, for longer cells, a spatial map of one-step estimates of the diffusion coefficient along x suggests that diffusion is ∼20-40% faster within nucleoids than in the ribosome-rich region lying between nucleoid lobes at the cell mid-plane. Fluorescence recovery after photobleaching yielded = 8.3 ± 1.6 μm(2)·s(-1), in agreement with the single-particle tracking results. Copyright © 2011 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  16. Slow unloading leads to DNA-bound β2-sliding clamp accumulation in live Escherichia coli cells

    PubMed Central

    Moolman, M. Charl; Krishnan, Sriram Tiruvadi; Kerssemakers, Jacob W. J.; van den Berg, Aafke; Tulinski, Pawel; Depken, Martin; Reyes-Lamothe, Rodrigo; Sherratt, David J.; Dekker, Nynke H.

    2014-01-01

    The ubiquitous sliding clamp facilitates processivity of the replicative polymerase and acts as a platform to recruit proteins involved in replication, recombination and repair. While the dynamics of the E. coli β2-sliding clamp have been characterized in vitro, its in vivo stoichiometry and dynamics remain unclear. To probe both β2-clamp dynamics and stoichiometry in live E. coli cells, we use custom-built microfluidics in combination with single-molecule fluorescence microscopy and photoactivated fluorescence microscopy. We quantify the recruitment, binding and turnover of β2-sliding clamps on DNA during replication. These quantitative in vivo results demonstrate that numerous β2-clamps in E. coli remain on the DNA behind the replication fork for a protracted period of time, allowing them to form a docking platform for other enzymes involved in DNA metabolism. PMID:25520215

  17. Slow unloading leads to DNA-bound β2-sliding clamp accumulation in live Escherichia coli cells

    NASA Astrophysics Data System (ADS)

    Moolman, M. Charl; Krishnan, Sriram Tiruvadi; Kerssemakers, Jacob W. J.; van den Berg, Aafke; Tulinski, Pawel; Depken, Martin; Reyes-Lamothe, Rodrigo; Sherratt, David J.; Dekker, Nynke H.

    2014-12-01

    The ubiquitous sliding clamp facilitates processivity of the replicative polymerase and acts as a platform to recruit proteins involved in replication, recombination and repair. While the dynamics of the E. coli β2-sliding clamp have been characterized in vitro, its in vivo stoichiometry and dynamics remain unclear. To probe both β2-clamp dynamics and stoichiometry in live E. coli cells, we use custom-built microfluidics in combination with single-molecule fluorescence microscopy and photoactivated fluorescence microscopy. We quantify the recruitment, binding and turnover of β2-sliding clamps on DNA during replication. These quantitative in vivo results demonstrate that numerous β2-clamps in E. coli remain on the DNA behind the replication fork for a protracted period of time, allowing them to form a docking platform for other enzymes involved in DNA metabolism.

  18. The antimalarial artemisinin synergizes with antibiotics to protect against lethal live Escherichia coli challenge by decreasing proinflammatory cytokine release.

    PubMed

    Wang, Jun; Zhou, Hong; Zheng, Jiang; Cheng, Juan; Liu, Wei; Ding, Guofu; Wang, Liangxi; Luo, Ping; Lu, Yongling; Cao, Hongwei; Yu, Shuangjiang; Li, Bin; Zhang, Lezhi

    2006-07-01

    In the present study artemisinin (ART) was found to have potent anti-inflammatory effects in animal models of sepsis induced by CpG-containing oligodeoxy-nucleotides (CpG ODN), lipopolysaccharide (LPS), heat-killed Escherichia coli 35218 or live E. coli. Furthermore, we found that ART protected mice from a lethal challenge by CpG ODN, LPS, or heat-killed E. coli in a dose-dependent manner and that the protection was related to a reduction in serum tumor necrosis factor alpha (TNF-alpha). More significantly, the administration of ART together with ampicillin or unasyn (a complex of ampicillin and sulbactam) decreased mortality from 100 to 66.7% or 33.3%, respectively, in mice subjected to a lethal live E. coli challenge. Together with the observation that ART alone does not inhibit bacterial growth, this result suggests that ART protection is achieved as a result of its anti-inflammatory activity rather than an antimicrobial effect. In RAW264.7 cells, pretreatment with ART potently inhibited TNF-alpha and interleukin-6 release induced by CpG ODN, LPS, or heat-killed E. coli in a dose- and time-dependent manner. Experiments utilizing affinity sensor technology revealed no direct binding of ART with CpG ODN or LPS. Flow cytometry further showed that ART did not alter binding of CpG ODN to cell surfaces or the internalization of CpG ODN. In addition, upregulated levels of TLR9 and TLR4 mRNA were not attenuated by ART treatment. ART treatment did, however, block the NF-kappaB activation induced by CpG ODN, LPS, or heat-killed E. coli. These findings provide compelling evidence that ART may be an important potential drug for sepsis treatment.

  19. Proton NMR spectral study of UV treated live Escherichia coli Bacteria

    NASA Astrophysics Data System (ADS)

    Sorokopud, Michael

    The lethal effects of ultraviolet radiation on microorganisms have been known and utilized for many years. In sufficiently high photon fluences, light and in particular, UV light, is an effective and subtle means of killing or at least immobilizing most, if not all cells and micro-organisms. Because of their small size, light can penetrate the enclosing protective walls and enter the inner volumes where it can break organic bonds in components that are vital to cell function. Despite the fact that a very low dose of UV light (1-9 mJ/cm2) has been shown to inactivate many micro-organisms, there remains a dearth of biological information about light induced effects in molecules and their interactions within living microbial systems. The use of 1H NMR as a spectroscopic tool was chosen to undertake an examination of the possible effects resulting from exposing E. coli to lethal fluencies of UV radiation. Once sample preparation, treatment, and NMR mounting methods were optimized, the high sensitivity and high resolution capabilities of the method produced reproducible results for a series of experiments. These results reveal significant changes in the ratio of the 1H NMR spectra of the treated to untreated E.coli samples when the treated sample was exposed to a lethal fluence of 275nm light. Photons at the 275nm wavelength, used in this study, have enough energy to break all of the principle bonds in an organic molecule. The difference spectrum between treated to untreated samples appears to be fitted well using specific component spectra from these groups of compounds. Increases in NMR peak amplitudes are observed and appear to be correlated with the spectral locations of several amino acids, membrane components and several sugars/saccharides. Increases in peak intensities of 4-8% were observed in the 0.8-1.1 ppm chemical shift region, characteristic of lipid and amino acid groups. A 3.5-4% increase was observed in the 2 ppm and 3.4-4 ppm region characteristic of

  20. Asymptomatic infections by diarrheagenic Escherichia coli in children from Misiones, Argentina, during the first twenty months of their lives.

    PubMed

    Quiroga, M; Oviedo, P; Chinen, I; Pegels, E; Husulak, E; Binztein, N; Rivas, M; Schiavoni, L; Vergara, M

    2000-01-01

    Diarrheagenics Escherichia coli are the major agents involved in diarrheal disease in developing countries. The aim of this study was to evaluate the time of appearance of the first asymptomatic infection by the different categories of diarrheagenic E. coli in 44 children since their birth and during the first 20 months of their lives. In all of the children studied, we detected at least one category of diarrheagenic E. coli through the 20 months of the study. 510 diarrheagenic E. coli (33.5%) were obtained from the 1,524 samples collected from the 44 children during the time of the study (31.4% EAggEC, 28.8% EPEC, 27.1% DAEC, and 12.7% ETEC). Neither EHEC nor EIEC were identified. The median age for diarrheagenic E. coli colonization was 7.5 months. The mean weaning period was 12.8 months and the mean age for introduction of mixed feeding (breast fed supplemented) was 3.8 months. A significantly lower incidence of diarrheal disease and asymptomatic infections was recorded among the exclusively breast-fed rather than in the supplemented and non breast-fed infants. For ETEC, EPEC and EAggEC the introduction of weaning foods and complete termination of breast-feeding were associated with an increase of asymptomatic infections.

  1. E. Coli

    MedlinePlus

    ... We Are Organization Director, Anthony Fauci, M.D. History What We ... Escherichia coli ( E. coli ) bacteria live in the intestines of people and animals, and are key to a healthy intestinal tract. ...

  2. Escherichia coli ghosts or live E. coli expressing the ferri-siderophore receptors FepA, FhuE, IroN and IutA do not protect broiler chickens against avian pathogenic E. coli (APEC).

    PubMed

    Tuntufye, Huruma Nelwike; Ons, Ellen; Pham, Anh Dao Nguyen; Luyten, Tom; Van Gerven, Nani; Bleyen, Nele; Goddeeris, Bruno Maria

    2012-10-12

    The aim of this study was to investigate if immunization with the ferri-siderophore receptors FepA, FhuE, IroN and IutA could protect chickens against avian pathogenic Escherichia coli (APEC) infection. The antigens were administered as recombinant proteins in the outer membrane (OM) of E. coli strain BL21 Star DE3. In a first immunization experiment, live E. coli expressing all 4 recombinant ferri-siderophore receptors (BL21(L)) were given intranasally. In a second immunization experiment, a mixture of E. coli ghosts containing recombinant FepA and IutA and ghosts containing recombinant FhuE and IroN was evaluated. For both experiments non-recombinant counterparts of the tentative vaccines were administered as placebo. At the time of challenge, the IgG antibody response for BL21(L) and a mixture of E. coli ghosts containing recombinant FepA and IutA and ghosts containing recombinant FhuE and IroN was significantly higher in all immunized groups as compared to the negative control groups (LB or PBS) confirming successful immunization. Although neither of the tentative vaccines could prevent lesions and mortality upon APEC infection, immunization with bacterial ghosts resulted in a decrease in mortality from 50% (PBS) to 31% (non-recombinant ghosts) or 20% (recombinant ghosts) and these differences were not found to be significant. Copyright © 2012 Elsevier B.V. All rights reserved.

  3. Probable secondary transmission of antimicrobial-resistant Escherichia coli between people living with and without pets.

    PubMed

    Chung, Yeon Soo; Park, Young Kyung; Park, Yong Ho; Park, Kun Taek

    2017-03-18

    Companion animals are considered as one of the reservoirs of antimicrobial-resistant (AR) bacteria that can be cross-transmitted to humans. However, limited information is available on the possibility of AR bacteria originating from companion animals being transmitted secondarily from owners to non-owners sharing the same space. To address this issue, the present study investigated clonal relatedness among AR E. coli isolated from dog owners and non-owners in the same college classroom or household. Anal samples (n=48) were obtained from 14 owners and 34 non-owners; 31 E. coli isolates were collected (nine from owners and 22 from non-owners). Of 31 E. coli, 20 isolates (64.5%) were resistant to at least one antimicrobial, and 16 isolates (51.6%) were determined as multi-drug resistant E. coli. Six isolates (19.4%) harbored integrase genes (five harbored class I integrase gene and one harbored class 2 integrase gene, respectively). Pulsed-field gel electrophoretic analysis identified three different E. coli clonal sets among isolates, indicating that cross-transmission of AR E. coli can easily occur between owners and non-owners. The findings emphasize a potential risk of spread of AR bacteria originating from pets within human communities, once they are transferred to humans. Further studies are needed to evaluate the exact risk and identify the risk factors of secondarily transmission by investigating larger numbers of isolates from pets, their owners and non-owners in a community.

  4. Probable secondary transmission of antimicrobial-resistant Escherichia coli between people living with and without pets

    PubMed Central

    CHUNG, Yeon Soo; PARK, Young Kyung; PARK, Yong Ho; PARK, Kun Taek

    2017-01-01

    Companion animals are considered as one of the reservoirs of antimicrobial-resistant (AR) bacteria that can be cross-transmitted to humans. However, limited information is available on the possibility of AR bacteria originating from companion animals being transmitted secondarily from owners to non-owners sharing the same space. To address this issue, the present study investigated clonal relatedness among AR E. coli isolated from dog owners and non-owners in the same college classroom or household. Anal samples (n=48) were obtained from 14 owners and 34 non-owners; 31 E. coli isolates were collected (nine from owners and 22 from non-owners). Of 31 E. coli, 20 isolates (64.5%) were resistant to at least one antimicrobial, and 16 isolates (51.6%) were determined as multi-drug resistant E. coli. Six isolates (19.4%) harbored integrase genes (five harbored class I integrase gene and one harbored class 2 integrase gene, respectively). Pulsed-field gel electrophoretic analysis identified three different E. coli clonal sets among isolates, indicating that cross-transmission of AR E. coli can easily occur between owners and non-owners. The findings emphasize a potential risk of spread of AR bacteria originating from pets within human communities, once they are transferred to humans. Further studies are needed to evaluate the exact risk and identify the risk factors of secondarily transmission by investigating larger numbers of isolates from pets, their owners and non-owners in a community. PMID:28190823

  5. Genetic Characterization and Immunogenicity of Coli Surface Antigen 4 from Enterotoxigenic Escherichia coli when It Is Expressed in a Shigella Live-Vector Strain

    PubMed Central

    Altboum, Zeev; Levine, Myron M.; Galen, James E.; Barry, Eileen M.

    2003-01-01

    The genes that encode the enterotoxigenic Escherichia coli (ETEC) CS4 fimbriae, csaA, -B, -C, -E, and -D′, were isolated from strain E11881A. The csa operon encodes a 17-kDa major fimbrial subunit (CsaB), a 40-kDa tip-associated protein (CsaE), a 27-kDa chaperone-like protein (CsaA), a 97-kDa usher-like protein (CsaC), and a deleted regulatory protein (CsaD′). The predicted amino acid sequences of the CS4 proteins are highly homologous to structural and assembly proteins of other ETEC fimbriae, including CS1 and CS2, and to CFA/I in particular. The csaA, -B, -C, -E operon was cloned on a stabilized plasmid downstream from an osomotically regulated ompC promoter. pGA2-CS4 directs production of CS4 fimbriae in both E. coli DH5α and Shigella flexneri 2a vaccine strain CVD 1204, as detected by Western blot analysis and bacterial agglutination with anti-CS4 immune sera. Electron-microscopic examination of Shigella expressing CS4 confirmed the presence of fimbriae on the bacterial surface. Guinea pigs immunized with CVD 1204(pGA2-CS4) showed serum and mucosal antibody responses to both the Shigella vector and the ETEC fimbria CS4. Among the seven most prevalent fimbrial antigens of human ETEC, CS4 is the last to be cloned and sequenced. These findings pave the way for CS4 to be included in multivalent ETEC vaccines, including an attenuated Shigella live-vector-based ETEC vaccine. PMID:12595452

  6. Dietary live yeast and mannan-oligosaccharide supplementation attenuate intestinal inflammation and barrier dysfunction induced by Escherichia coli in broilers.

    PubMed

    Wang, Weiwei; Li, Zhui; Han, Qiqi; Guo, Yuming; Zhang, Bo; D'inca, Romain

    2016-12-01

    The effects of live yeast (LY) and mannan-oligosaccharide (MOS) supplementation on intestinal disruption induced by Escherichia coli in broilers were investigated. The experimental design was a 3×2 factorial arrangement with three dietary treatments (control, 0·5 g/kg LY (Saccharomyces cerevisiae, 1·0×1010 colony-forming units/g), 0·5 g/kg MOS) and two immune treatments (with or without E. coli challenge from 7 to 11 d of age). Samples were collected at 14 d of age. The results showed that E. coli challenge impaired (P<0·05) growth performance during the grower period (1-21 d) and the overall period (1-35 d) of broilers, increased (P<0·05) serum endotoxin and diamine oxidase levels coupled with ileal myeloperoxidase and lysozyme activities, whereas reduced (P<0·05) maltase activity, and compromised the morphological structure of the ileum. Besides, it increased (P<0·05) the mRNA expressions of several inflammatory genes and reduced occludin expression in the ileum. Dietary treatment with both LY and MOS reduced (P<0·05) serum diamine oxidase and ileal myeloperoxidase levels, but elevated villus height (P<0·10) and the ratio of villus height:crypt depth (P<0·05) of the ileum. It also alleviated (P<0·05) E. coli-induced increases (P<0·05) in ileal Toll-like receptor 4, NF-κ B and IL-1 β expressions. Moreover, LY supplementation reduced (P<0·05) feed conversion ratio of birds during the grower period and enhanced (P<0·05) the community diversity (Shannon and Simpson indices) of ileal microbiota, whereas MOS addition counteracted (P<0·05) the decreased ileal IL-10 and occludin expressions in challenged birds. In conclusion, both LY and MOS supplementation could attenuate E. coli-induced intestinal disruption by alleviating intestinal inflammation and barrier dysfunction in broilers. Moreover, LY addition could improve intestinal microbial community structure and feed efficiency of broilers.

  7. Transcription-Factor-Mediated DNA Looping Probed by High-Resolution, Single-Molecule Imaging in Live E. coli Cells

    PubMed Central

    Hensel, Zach; Xiao, Jie

    2013-01-01

    DNA looping mediated by transcription factors plays critical roles in prokaryotic gene regulation. The “genetic switch” of bacteriophage λ determines whether a prophage stays incorporated in the E. coli chromosome or enters the lytic cycle of phage propagation and cell lysis. Past studies have shown that long-range DNA interactions between the operator sequences OR and OL (separated by 2.3 kb), mediated by the λ repressor CI (accession number P03034), play key roles in regulating the λ switch. In vitro, it was demonstrated that DNA segments harboring the operator sequences formed loops in the presence of CI, but CI-mediated DNA looping has not been directly visualized in vivo, hindering a deep understanding of the corresponding dynamics in realistic cellular environments. We report a high-resolution, single-molecule imaging method to probe CI-mediated DNA looping in live E. coli cells. We labeled two DNA loci with differently colored fluorescent fusion proteins and tracked their separations in real time with ∼40 nm accuracy, enabling the first direct analysis of transcription-factor-mediated DNA looping in live cells. Combining looping measurements with measurements of CI expression levels in different operator mutants, we show quantitatively that DNA looping activates transcription and enhances repression. Further, we estimated the upper bound of the rate of conformational change from the unlooped to the looped state, and discuss how chromosome compaction may impact looping kinetics. Our results provide insights into transcription-factor-mediated DNA looping in a variety of operator and CI mutant backgrounds in vivo, and our methodology can be applied to a broad range of questions regarding chromosome conformations in prokaryotes and higher organisms. PMID:23853547

  8. Transcription-factor-mediated DNA looping probed by high-resolution, single-molecule imaging in live E. coli cells.

    PubMed

    Hensel, Zach; Weng, Xiaoli; Lagda, Arvin Cesar; Xiao, Jie

    2013-01-01

    DNA looping mediated by transcription factors plays critical roles in prokaryotic gene regulation. The "genetic switch" of bacteriophage λ determines whether a prophage stays incorporated in the E. coli chromosome or enters the lytic cycle of phage propagation and cell lysis. Past studies have shown that long-range DNA interactions between the operator sequences O(R) and O(L) (separated by 2.3 kb), mediated by the λ repressor CI (accession number P03034), play key roles in regulating the λ switch. In vitro, it was demonstrated that DNA segments harboring the operator sequences formed loops in the presence of CI, but CI-mediated DNA looping has not been directly visualized in vivo, hindering a deep understanding of the corresponding dynamics in realistic cellular environments. We report a high-resolution, single-molecule imaging method to probe CI-mediated DNA looping in live E. coli cells. We labeled two DNA loci with differently colored fluorescent fusion proteins and tracked their separations in real time with ∼40 nm accuracy, enabling the first direct analysis of transcription-factor-mediated DNA looping in live cells. Combining looping measurements with measurements of CI expression levels in different operator mutants, we show quantitatively that DNA looping activates transcription and enhances repression. Further, we estimated the upper bound of the rate of conformational change from the unlooped to the looped state, and discuss how chromosome compaction may impact looping kinetics. Our results provide insights into transcription-factor-mediated DNA looping in a variety of operator and CI mutant backgrounds in vivo, and our methodology can be applied to a broad range of questions regarding chromosome conformations in prokaryotes and higher organisms.

  9. N-Chlorotaurine, a Long-Lived Oxidant Produced by Human Leukocytes, Inactivates Shiga Toxin of Enterohemorrhagic Escherichia coli

    PubMed Central

    Eitzinger, Christian; Ehrlenbach, Silvia; Lindner, Herbert; Kremser, Leopold; Gottardi, Waldemar; Debabov, Dmitri; Anderson, Mark

    2012-01-01

    N-chlorotaurine (NCT), the main representative of long-lived oxidants produced by granulocytes and monocytes, is known to exert broad-spectrum microbicidal activity. Here we show that NCT directly inactivates Shiga toxin 2 (Stx2), used as a model toxin secreted by enterohemorrhagic Escherichia coli (EHEC). Bacterial growth and Stx2 production were both inhibited by 2 mM NCT. The cytotoxic effect of Stx2 on Vero cells was removed by ≥5.5 mM NCT. Confocal microscopy and FACS analyses showed that the binding of Stx2 to human kidney glomerular endothelial cells was inhibited, and no NCT-treated Stx2 entered the cytosol. Mass spectrometry displayed oxidation of thio groups and aromatic amino acids of Stx2 by NCT. Therefore, long-lived oxidants may act as powerful tools of innate immunity against soluble virulence factors of pathogens. Moreover, inactivation of virulence factors may contribute to therapeutic success of NCT and novel analogs, which are in development as topical antiinfectives. PMID:23139739

  10. Effects of volume resuscitation on splanchnic perfusion in canine model of severe sepsis induced by live Escherichia coli infusion

    PubMed Central

    Lagoa, Claudio Esteves; de Figueiredo, Luiz Francisco Poli; Cruz, Ruy Jorge; Silva, Eliézer; Rocha e Silva, Maurício

    2004-01-01

    Introduction We conducted the present study to investigate whether early large-volume crystalloid infusion can restore gut mucosal blood flow and mesenteric oxygen metabolism in severe sepsis. Methods Anesthetized and mechanically ventilated male mongrel dogs were challenged with intravenous injection of live Escherichia coli (6 × 109 colony-forming units/ml per kg over 15 min). After 90 min they were randomly assigned to one of two groups – control (no fluids; n = 13) or lactated Ringer's solution (32 ml/kg per hour; n = 14) – and followed for 60 min. Cardiac index, mesenteric blood flow, mean arterial pressure, systemic and mesenteric oxygen-derived variables, blood lactate and gastric carbon dioxide tension (PCO2; by gas tonometry) were assessed throughout the study. Results E. coli infusion significantly decreased arterial pressure, cardiac index, mesenteric blood flow, and systemic and mesenteric oxygen delivery, and increased arterial and portal lactate, intramucosal PCO2, PCO2 gap (the difference between gastric mucosal and arterial PCO2), and systemic and mesenteric oxygen extraction ratio in both groups. The Ringer's solution group had significantly higher cardiac index and systemic oxygen delivery, and lower oxygen extraction ratio and PCO2 gap at 165 min as compared with control animals. However, infusion of lactated Ringer's solution was unable to restore the PCO2 gap. There were no significant differences between groups in mesenteric oxygen delivery, oxygen extraction ratio, or portal lactate at the end of study. Conclusion Significant disturbances occur in the systemic and mesenteric beds during bacteremic severe sepsis. Although large-volume infusion of lactated Ringer's solution restored systemic hemodynamic parameters, it was unable to correct gut mucosal PCO2 gap. PMID:15312221

  11. Single-Cell, Time-Resolved Antimicrobial Effects of a Highly Cationic, Random Nylon-3 Copolymer on Live Escherichia coli.

    PubMed

    Choi, Heejun; Chakraborty, Saswata; Liu, Runhui; Gellman, Samuel H; Weisshaar, James C

    2016-01-15

    Synthetic random copolymers based on the nylon-3 (β-peptide) backbone show promise as inexpensive antimicrobial agents resistant to proteolysis. We present a time-resolved observational study of the attack of a particular copolymer MM63:CHx37 on single, live Escherichia coli cells. The composition and chain length of MM63:CHx37 (63% cationic subunits, 37% hydrophobic subunits, 35-subunit average length) were optimized to enhance antibacterial activity while minimizing lysis of human red blood cells. For E. coli cells that export GFP to the periplasm, we obtain alternating phase-contrast and green fluorescence images with a time resolution of 12 s over 60 min following initiation of copolymer flow. Within seconds, cells shrink and exhibit the same plasmolysis spaces that occur following abrupt external osmotic upshift. The osmoprotection machinery attempts to replenish cytoplasmic water, but recovery is interrupted by permeabilization of the cytoplasmic membrane (CM) to GFP. Evidently, the highly cationic copolymer and its counterions rapidly translocate across the outer membrane without permeabilizing it to GFP. The CM permeabilization event is spatially localized. Cells whose CM has been permeabilized never recover growth. The minimum inhibitory concentration (MIC) for cells lacking the osmolyte importer ProP is 4-fold smaller than for normal cells, suggesting that osmoprotection is an important survival strategy. In addition, at the time of CM permeabilization, we observe evidence of oxidative stress. The MIC under anaerobic conditions is at least 8-fold larger than under aerobic conditions, further implicating oxidative damage as an important bacteriostatic effect. Once the copolymer reaches the periplasm, multiple growth-halting mechanisms proceed in parallel.

  12. Application of propidium monoazide quantitative PCR for selective detection of live Escherichia coli O157:H7 in vegetables after inactivation by essential oils.

    PubMed

    Elizaquível, Patricia; Sánchez, Gloria; Aznar, Rosa

    2012-10-01

    The use of propidium monoazide (PMA) is enjoying increased popularity among researchers in different fields of microbiology. Its use in combination with real-time PCR (qPCR) represents one of the most successful approaches to detect viable cells. PMA-qPCR has successfully been used to evaluate the efficacy of various disinfection technologies in different microorganisms. Initially, in this study the effect of four essential oils (EOs), cumin, clove, oregano and cinnamon, was evaluated on suspensions of the enterohemorrhagic Escherichia coli O157:H7 by PMA-qPCR, LIVE/DEAD BacLight flow cytometry analysis (LIVE/DEAD-FCM), and plate count. E. coli O157:H7 cells treated with EOs at killing concentrations were permeable to PMA which was confirmed by LIVE/DEAD-FCM. However, the PMA-qPCR assay allows specific quantification among the autochthonous microbiota of food products. Therefore, the PMA-qPCR assay was used to evaluate its applicability in artificially contaminated iceberg lettuce and soya sprouts. Amplification signal was negative for the spiking tests performed with any of the EO-killed E. coli cells. It demonstrates that the PMA-qPCR assay is a suitable technique for monitoring E. coli O157:H7 inactivation by essential oils in fresh-cut vegetables.

  13. Efficacy evaluation of live Escherichia coli expression Brucella P39 protein combined with CpG oligodeoxynucleotides vaccine against Brucella melitensis 16M, in BALB/c mice.

    PubMed

    Al-Mariri, Ayman; Mahmoud, Nermeen Haj; Hammoud, Razan

    2012-03-01

    Brucella is gram-negative bacteria responsible for brucellosis in a wide variety of animals and humans. BALB/c mice were immunized with live Escherichia coli expression the p39 gene of Brucella melitensis, a gene coding for the periplasmic binding protein. Mice were injected with either E. coli BL21 (DE3) pEt15b or E. coli BL21 (DE3) pEt15b-p39 alone or adjuvanted with either CpG oligodeoxynucleotides (CpG ODN) or non-CpG ODN. E. coli BL21 (DE3) pEt15b-p39 with CpG ODN or with non-CpG ODN mice groups showed a significant IFN-γ production and T-cell proliferation as a reaction to P39 antigen. In addition, antibody responses (IgG, IgG1 and IgG2a), were only found in these two mice groups. A higher level of protection against B. melitensis 16M were observed in mice immunized with E. coli BL21 (DE3) pEt15b-p39 and CpG ODN comparing with those immunized with E. coli BL21 (DE3) pEt15b-p39 alone or with non-CpG ODN. No protection against B. melitensis 16M was observed in mice immunized with E. coli BL21 (DE3) pEt15b alone or with the adjuvant. Rev.1 protection at 4 and 8 weeks post-challenge was more effective than that observed with E. coli BL21 (DE3) pEt15b-p39 and CpG ODN.

  14. False positive RNA binding activities after Ni-affinity purification from Escherichia coli.

    PubMed

    Milojevic, Tetyana; Sonnleitner, Elisabeth; Romeo, Alessandra; Djinović-Carugo, Kristina; Bläsi, Udo

    2013-06-01

    A His-tag is often added by means of recombinant DNA technology to a heterologous protein of interest, which is then over-produced in Escherchia coli and purified by one-step immobilized metal-affinity chromatography (IMAC). Owing to the presence of 24 histidines at the C-termini of the hexameric E. coli RNA chaperone Hfq, the protein co-purifies with His-tagged proteins of interest. As Hfq can bind to distinct RNA substrates with high affinity, its presence can obscure studies performed with (putative) RNA binding activities purified by IMAC. Here, we present results for a seemingly positive RNA-binding activity, exemplifying that false-positive results can be avoided if the protein of interest is either subjected to further purification step(s) or produced in an E. coli hfq- strain.

  15. Spatial Distribution and Ribosome-Binding Dynamics of EF-P in Live Escherichia coli.

    PubMed

    Mohapatra, Sonisilpa; Choi, Heejun; Ge, Xueliang; Sanyal, Suparna; Weisshaar, James C

    2017-06-06

    In vitro assays find that ribosomes form peptide bonds to proline (Pro) residues more slowly than to other residues. Ribosome profiling shows that stalling at Pro-Pro-X triplets is especially severe but is largely alleviated in Escherichia coli by the action of elongation factor EF-P. EF-P and its eukaryotic/archaeal homolog IF5A enhance the peptidyl transfer step of elongation. Here, a superresolution fluorescence localization and tracking study of EF-P-mEos2 in live E. coli provides the first in vivo information about the spatial distribution and on-off binding kinetics of EF-P. Fast imaging at 2 ms/frame helps to distinguish ribosome-bound (slowly diffusing) EF-P from free (rapidly diffusing) EF-P. Wild-type EF-P exhibits a three-peaked axial spatial distribution similar to that of ribosomes, indicating substantial binding. The mutant EF-P(K34A) exhibits a homogeneous distribution, indicating little or no binding. Some 30% of EF-P copies are bound to ribosomes at a given time. Two-state modeling and copy number estimates indicate that EF-P binds to 70S ribosomes during 25 to 100% of translation cycles. The timescale of the typical diffusive search by free EF-P for a ribosome-binding site is τfree ≈ 16 ms. The typical residence time of an EF-P on the ribosome is very short, τbound ≈ 7 ms. Evidently, EF-P binds to ribosomes during many or most elongation cycles, much more often than the frequency of Pro-Pro motifs. Emptying of the E site during part of the cycle is consistent with recent in vitro experiments indicating dissociation of the deacylated tRNA upon translocation.IMPORTANCE Ribosomes translate the codon sequence within mRNA into the corresponding sequence of amino acids within the nascent polypeptide chain, which in turn ultimately folds into functional protein. At each codon, bacterial ribosomes are assisted by two well-known elongation factors: EF-Tu, which aids binding of the correct aminoacyl-tRNA to the ribosome, and EF-G, which promotes

  16. Single-molecule imaging of UvrA and UvrB recruitment to DNA lesions in living Escherichia coli

    PubMed Central

    Stracy, Mathew; Jaciuk, Marcin; Uphoff, Stephan; Kapanidis, Achillefs N.; Nowotny, Marcin; Sherratt, David J.; Zawadzki, Pawel

    2016-01-01

    Nucleotide excision repair (NER) removes chemically diverse DNA lesions in all domains of life. In Escherichia coli, UvrA and UvrB initiate NER, although the mechanistic details of how this occurs in vivo remain to be established. Here, we use single-molecule fluorescence imaging to provide a comprehensive characterization of the lesion search, recognition and verification process in living cells. We show that NER initiation involves a two-step mechanism in which UvrA scans the genome and locates DNA damage independently of UvrB. Then UvrA recruits UvrB from solution to the lesion. These steps are coordinated by ATP binding and hydrolysis in the ‘proximal' and ‘distal' UvrA ATP-binding sites. We show that initial UvrB-independent damage recognition by UvrA requires ATPase activity in the distal site only. Subsequent UvrB recruitment requires ATP hydrolysis in the proximal site. Finally, UvrA dissociates from the lesion complex, allowing UvrB to orchestrate the downstream NER reactions. PMID:27562541

  17. Temperature-Dependent Model of Multi-step Transcription Initiation in Escherichia coli Based on Live Single-Cell Measurements

    PubMed Central

    Lloyd-Price, Jason; Tran, Huy; Ribeiro, Andre S.

    2016-01-01

    Transcription kinetics is limited by its initiation steps, which differ between promoters and with intra- and extracellular conditions. Regulation of these steps allows tuning both the rate and stochasticity of RNA production. We used time-lapse, single-RNA microscopy measurements in live Escherichia coli to study how the rate-limiting steps in initiation of the Plac/ara-1 promoter change with temperature and induction scheme. For this, we compared detailed stochastic models fit to the empirical data in maximum likelihood sense using statistical methods. Using this analysis, we found that temperature affects the rate limiting steps unequally, as nonlinear changes in the closed complex formation suffice to explain the differences in transcription dynamics between conditions. Meanwhile, a similar analysis of the PtetA promoter revealed that it has a different rate limiting step configuration, with temperature regulating different steps. Finally, we used the derived models to explore a possible cause for why the identified steps are preferred as the main cause for behavior modifications with temperature: we find that transcription dynamics is either insensitive or responds reciprocally to changes in the other steps. Our results suggests that different promoters employ different rate limiting step patterns that control not only their rate and variability, but also their sensitivity to environmental changes. PMID:27792724

  18. Typing of Campylobacter jejuni and Campylobacter coli isolated from live broilers and retail broiler meat by flaA-RFLP, MLST, PFGE and REP-PCR.

    PubMed

    Behringer, Megan; Miller, William G; Oyarzabal, Omar A

    2011-02-01

    We analyzed 100 Campylobacter spp. isolates (C. jejuni and C. coli) from Grenada, Puerto Rico and Alabama, which were collected from live broilers or retail broiler meat. We analyzed these isolates with four molecular typing methods: restriction fragment length polymorphism of the flaA gene (flaA-RFLP), multilocus sequence typing (MLST), pulsed-field gel electrophoresis (PFGE), and automated repetitive extragenic palindromic polymerase chain reaction (REP-PCR) using the DiversiLab system. All methods performed similarly for the typing of C. jejuni and C. coli. The DNA extraction method appears to influence the results obtained with REP-PCR. This method was better for the typing of C. jejuni than C. coli, however both REP-PCR and flaA-RFLP generated types that were indistinguishable between C. jejuni and C. coli and appeared to be random, without any relationship to species, location, or source of isolates. PFGE and MLST generated typing results that had a better correlation with the geographic location of the isolates and showed higher concordance with the Wallace coefficient. The adjusted Rand coefficient did not show higher concordance among the methods, although the PFGE/MLST combination exhibited the highest concordance. PFGE and MLST revealed a better discriminatory power for C. coli isolates than REP-PCR or flaA-RFLP. The use of readily available online tools to calculate the confidence interval of the Simpson's index of diversity and the adjusted Rand and Wallace coefficients helped estimate the discriminatory power of typing methods. Further studies using different C. jejuni and C. coli strains may expand our understanding of the benefits and limitations of each of these typing methods for epidemiological studies of Campylobacter spp.

  19. A carAB mutant of avian pathogenic Escherichia coli serogroup O2 is attenuated and effective as a live oral vaccine against colibacillosis in turkeys.

    PubMed Central

    Kwaga, J K; Allan, B J; van der Hurk, J V; Seida, H; Potter, A A

    1994-01-01

    Colibacillosis is a serious and economically important disease of the respiratory tract of chickens and turkeys. The serogroups of Escherichia coli commonly associated with colibacillosis in poultry are O1, O2, and O78. Although previous attempts to develop a vaccine have not been very successful, vaccination is still considered the most effective way of controlling the disease. Therefore, our laboratory has been involved in the development of an attenuated live vaccine that will be effective in the prevention of colibacillosis. The carAB operon coding for carbamoyl-phosphate synthetase, an essential enzyme in arginine and pyrimidine metabolism, was selected for study. Generalized transduction was used to transfer a Tn10-generated mutation from a laboratory strain to virulent avian field isolates of E. coli. Molecular techniques were used to determine the point of Tn10 insertion within the carAB operon. The insertion mutants were then cured of the tetracycline resistance gene of the transposon to select for antibiotic-sensitive and stable carAB mutants. The degree of attenuation obtained by the mutation was determined in day-old chickens. Typically, when 100-fold the 50% lethal dose (for the wild type) was given, no more than 50% mortality in the day-old chickens was observed. The deletion mutant of serotype O2 was also found to be avirulent in turkeys rendered susceptible to infection with hemorrhagic enteritis virus A. Turkey poults vaccinated orally at 4 weeks old with either the wild-type E. coli EC317 strain or its carAB mutant EC751 were completely protected from infection following challenge with the homologous wild-type strain. Our data indicate that carAB mutants of virulent avian strains of E. coli will be effective and safe as live oral vaccines for prevention of colibacillosis in poultry. Images PMID:8063392

  20. A microbiological hazard of rural living: Clostridium septicum brain abscess in a child with E coli 0157 associated haemolytic uraemic syndrome

    PubMed Central

    Williams, Eleri J; Mitchell, Patrick; Mitra, Dipayan; Clark, Julia E

    2012-01-01

    Clostridium septicum infection in humans is rare and this is the second case report of focal C septicum brain abscesses associated with Escherichia coli 0157 haemolytic uraemic syndrome (HUS). The case presented in a child who lived on a rural farm. The abscesses initially progressed despite 7 months of appropriate antibiotic therapy and repeated image-guided aspiration. After definitive resection and prolonged antibiotic therapy, there was no recurrence. This case reminds us of this rare but important neurological complication of HUS and supports consideration of early definitive neurosurgical intervention in similar unusual cases. PMID:22736786

  1. Early systemic inflammatory response in mice after a single oral gavage with live Escherichia coli is evidenced by increased TNF-alpha and nitric oxide production.

    PubMed

    Nemec, Ana; Jerin, Aleš; Zdovc, Irena; Budefeld, Tomaž; Verstraete, Frank J M; Eržen, Damijan; Sentjurc, Marjeta; Petelin, Milan; Hitti, Tina; Pavlica, Zlatko

    2012-06-01

    Twenty-four female BALB/c mice were orally inoculated with 10(8) CFU Escherichia coli ATCC 25922 and euthanized 2.5, 7, 13 and 25 h post-inoculation. The levels of organ nitric oxide (NO) and plasma endotoxin, TNF-alpha and nitrite/nitrate (NO(x)) were compared to those found in sham-inoculated mice, to evaluate systemic host-response to a low-level oral exposure to Gram-negative bacteria. Organ bacterial culture and immunohistochemistry for iNOS were performed on lungs, liver, kidneys and brain from all mice. Organ NO and plasma TNF-alpha levels were higher in E. coli-inoculated animals, but no differences were detected in plasma endotoxin levels, NO(x) or iNOS immunostaining for any of the animal groups. Single oral gavage with live E. coli stimulates an early systemic immune response in clinically healthy mice as evidenced by increased plasma TNF-alpha and organ NO levels, but bacteremia and endotoxemia are not related to this inflammatory response.

  2. Survival characteristics of diarrheagenic Escherichia coli pathotypes and Helicobacter pylori during passage through the free-living ciliate, Tetrahymena sp.

    USDA-ARS?s Scientific Manuscript database

    Ciliates prey on bacteria in water and waste water systems. Compartmentalization of ingested material (including bacteria) in the food vacuoles of Tetrahymena and its egestion in the fecal pellet has been described and the survival of Salmonella enterica and E. coli O157:H7 in such fecal pellets ha...

  3. E. Coli and Pregnancy

    MedlinePlus

    ... best live chat Live Help Fact Sheets Share E. coli and Pregnancy Thursday, 20 November 2014 In ... pregnancy and while breastfeeding. Donate Sign Up For E-Newsletter Full Name * Email Address * Enter The Code: ...

  4. Colony-live —a high-throughput method for measuring microbial colony growth kinetics— reveals diverse growth effects of gene knockouts in Escherichia coli

    PubMed Central

    2014-01-01

    Background Precise quantitative growth measurements and detection of small growth changes in high-throughput manner is essential for fundamental studies of bacterial cell. However, an inherent tradeoff for measurement quality in high-throughput methods sacrifices some measurement quality. A key challenge has been how to enhance measurement quality without sacrificing throughput. Results We developed a new high-throughput measurement system, termed Colony-live. Here we show that Colony-live provides accurate measurement of three growth values (lag time of growth (LTG), maximum growth rate (MGR), and saturation point growth (SPG)) by visualizing colony growth over time. By using a new normalization method for colony growth, Colony-live gives more precise and accurate growth values than the conventional method. We demonstrated the utility of Colony-live by measuring growth values for the entire Keio collection of Escherichia coli single-gene knockout mutants. By using Colony-live, we were able to identify subtle growth defects of single-gene knockout mutants that were undetectable by the conventional method quantified by fixed time-point camera imaging. Further, Colony-live can reveal genes that influence the length of the lag-phase and the saturation point of growth. Conclusions Measurement quality is critical to achieving the resolution required to identify unique phenotypes among a diverse range of phenotypes. Sharing high-quality genome-wide datasets should benefit many researchers who are interested in specific gene functions or the architecture of cellular systems. Our Colony-live system provides a new powerful tool to accelerate accumulation of knowledge of microbial growth phenotypes. PMID:24964927

  5. Searching for novel modes of toxic actions of oil spill using E. coli live cell array reporter system - A Hebei Spirit oil spill study.

    PubMed

    Jung, Dawoon; Guan, Miao; Lee, Sangwoo; Kim, Cheolmin; Shin, Hyesoo; Hong, Seongjin; Yim, Un Hyuk; Shim, Won Joon; Giesy, John P; Khim, Jong Seong; Zhang, Xiaowei; Choi, Kyungho

    2017-02-01

    Oil is a complex mixture of numerous compounds. Therefore, oil spills near shore can cause various adverse effects on coastal ecosystems. However, most toxicological assessments conducted on oil spill sites have focused on limited modes of toxic actions. In the present study, we utilized the Escherichia coli (E. coli) live cell array system (LCA) to identify novel modes of toxicities of the oil spill-affected sediments. For this purpose, sediment samples were collected from an area heavily polluted by Hebei Spirit oil spill (HSOS) incident of 2007. A total of 93 E. coli reporter genes were used to study responses to the chemicals in the mixture. E. coli K12 strains were exposed to extracts of oil or the sediment, and changes in gene expression were measured. Exposure to extracts of crude and weathered oil resulted in decreased expression in ∼30% of tested genes. However, changes in expression observed after exposure to sediment extracts varied. Sediment extracts containing large concentrations of polycyclic aromatic hydrocarbons (PAH) caused down-regulation of >70% of the genes, while extracts containing lesser total concentrations of PAHs exhibited different trends: genes involved in drug resistance were generally up-regulated, while genes responsive to DNA damage were up-regulated in only two extracts. Results suggest that oil pollution can modulate several toxic response pathways related to DNA repair and antibiotic responses. Results from LCA obtained from the sediment and oil samples were different from those observed in the H4IIE-luc assay. Toxicological implications of such observations deserve further examination. Overall, LCA is a promising tool for screening samples and identifying potential modes of toxicities of environmental samples associated with oil spills.

  6. Dynamics of transcription driven by the tetA promoter, one event at a time, in live Escherichia coli cells.

    PubMed

    Muthukrishnan, Anantha-Barathi; Kandhavelu, Meenakshisundaram; Lloyd-Price, Jason; Kudasov, Fedor; Chowdhury, Sharif; Yli-Harja, Olli; Ribeiro, Andre S

    2012-09-01

    In Escherichia coli, tetracycline prevents translation. When subject to tetracycline, E. coli express TetA to pump it out by a mechanism that is sensitive, while fairly independent of cellular metabolism. We constructed a target gene, PtetA-mRFP1-96BS, with a 96 MS2-GFP binding site array in a single-copy BAC vector, whose expression is controlled by the tetA promoter. We measured the in vivo kinetics of production of individual RNA molecules of the target gene as a function of inducer concentration and temperature. From the distributions of intervals between transcription events, we find that RNA production by PtetA is a sub-Poissonian process. Next, we infer the number and duration of the prominent sequential steps in transcription initiation by maximum likelihood estimation. Under full induction and at optimal temperature, we observe three major steps. We find that the kinetics of RNA production under the control of PtetA, including number and duration of the steps, varies with induction strength and temperature. The results are supported by a set of logical pairwise Kolmogorov-Smirnov tests. We conclude that the expression of TetA is controlled by a sequential mechanism that is robust, whereas sensitive to external signals.

  7. The influence of dietary locust bean gum and live yeast on some digestive immunological parameters of piglets experimentally challenged with Escherichia coli.

    PubMed

    Badia, R; Lizardo, R; Martinez, P; Badiola, I; Brufau, J

    2012-12-01

    Gums and yeast cells are natural mannose-rich products that can be used as subtracts for adhesion of gram-negative bacteria. The aim of the study was to investigate the role of dietary locust bean gum (LBG; Salmosan, ITPSA, Spain) or live yeast (Saccharomyces cerevisiae Sc47; Actisaf, Lesaffre, France) as immunological enhancers of the intestinal function of piglets. Treatments included a noninfected group fed with a control diet and 4 other groups orally challenged with 1x10(8) cfu of Escherichia coli K88. The challenged groups were fed the control or the control diet supplemented with colistin, LBG, or yeast. Twenty-five Landrace × Duroc piglets weaned at 4 wk were used. The animals were group housed, challenged on day 14, and euthanized 2 d later. Blood, bile, ileum, and mesenteric lymph node (MLN) samples were obtained for analysis of C-reactive protein (CRP), secretory immunoglobulin A (sIgA), and Toll-like receptors 2 (TLR2) and 4 (TLR4). Challenge increased the level of CRP of piglets fed the control diet, but this did not happen in the piglets fed the supplemented diets (P < 0.001). Challenge upregulated TLR2 in MLN and TLR4 in ileum and MLN (P < 0.05). This was prevented by yeast supplementation for the TLR2 in MLN and TLR4 in ileum. Pigs fed colistin and LBG diets showed intermediate but nonsignificant responses. In conclusion, the results suggest that colistin, live yeast, and LBG reduce the levels of CRP in blood of piglets challenged with E. coli, and yeast reduces the expression of Toll-like receptors in the intestine.

  8. Exploring the frontier between life and death in Escherichia coli: evaluation of different viability markers in live and heat- or UV-killed cells.

    PubMed

    Villarino, A; Bouvet, O M; Regnault, B; Martin-Delautre, S; Grimont PAD

    2000-11-01

    A number of methods have been proposed to assess the viability of cells without culture. Each method is based on criteria that reflect different levels of cellular integrity or functionality. As a consequence, the interpretation of viability is often ambiguous. The purposes of this work were to evaluate the capacity of current viability markers to distinguish between live and dead Escherichia coli K-12 cells. Methods that assess 'viability' by the demonstration of metabolic activities (esterase activity, active electron transport chain, transport of glucose), cellular integrity (membrane integrity, presence of nucleic acids) or the building up of cellular material (cell elongation) have been evaluated in live and UV- or heat-killed cells. With live cells, viability markers detected cells in counts similar to the colony count. However, these so-called viability markers could stain dead cells for some time after the lethal treatment. For the UV-killed cells, residual activities were detected even after 48 h of storage at 20 degrees C. However, for heat-treated cells, these activities disappeared within hours after heat treatment. Only a combination of fluorescence in situ hybridization with rRNA probes and cell elongation in response to nutrients (in the presence of an inhibitor of cell division) had the ability to differentiate live from dead cells. Problems in the definition of a viable but nonculturable state are in part due to the lack of a clear definition of bacterial death. We consider death as an irreversible state where no growth, cell elongation or protein synthesis may occur.

  9. Monoxenic liquid culture with Escherichia coli of the free-living nematode Panagrolaimus sp. (strain NFS 24-5), a potential live food candidate for marine fish and shrimp larvae.

    PubMed

    Ayub, Farhana; Seychelles, Laurent; Strauch, Olaf; Wittke, Martina; Ehlers, Ralf-Udo

    2013-09-01

    The free-living, bacterial-feeding nematode Panagrolaimus sp. (strain NFS 24-5) has potential for use as live food for marine shrimp and fish larvae. Mass production in liquid culture is a prerequisite for its commercial exploitation. Panagrolaimus sp. was propagated in monoxenic liquid culture on Escherichia coli and parameters, like nematode density, population dynamics and biomass were recorded and compared with life history table data. A mean maximum nematode density of 174,278 mL(-1) and a maximum of 251,000 mL(-1) were recorded on day 17 after inoculation. Highest average biomass was 40 g L(-1) at day 13. The comparison with life history table data indicated that the hypothetical potential of liquid culture is much higher than documented during this investigation. Nematode development is delayed in liquid culture and egg production per female is more than five times lower than reported from life history trait analysis. The latter assessed a nematode generation time of 7.1 days, whereas the process time at maximum nematode density in liquid culture was 16 days indicating that a reduction of the process time can be achieved by further investigating the influence of nematode inoculum density on population development. The results challenge future research to reduce process time and variability and improve population dynamics also during scale-up of the liquid culture process.

  10. Activation of the complement system in baboons challenged with live Escherichia coli: correlation with mortality and evidence for a biphasic activation pattern.

    PubMed Central

    de Boer, J P; Creasey, A A; Chang, A; Roem, D; Eerenberg, A J; Hack, C E; Taylor, F B

    1993-01-01

    Activation of the complement system was studied in baboons that were challenged with live Escherichia coli. In the group challenged with a lethal dose (n = 4), the complement activation parameters C3b/c, C4b/c, and C5b-9 increased 13, 5, and 12 times the baseline value, respectively, during the first 6 h after the E. coli infusion, whereas in the group challenged with a sublethal dose (n = 10), they increased only moderately, by 2 to 3 times the baseline value. However, in this latter group, a more pronounced activation occurred at 24 h. Subsequent experiments showed that this second phase in complement activation started at 6 h after the challenge, at which time infused microorganisms had been cleared from the circulation. The simultaneous increase in C-reactive protein with this second phase suggested an endogenous activation mechanism involving this acute-phase protein. Levels of inactivated (modified) C1 inhibitor also increased in both groups, with peak levels of 2.5 times the baseline value at 24 h in the sublethal group and of 4 times at 6 h after the challenge in the lethal group. Thus, activation of complement in this animal model for sepsis occurs in a biphasic pattern, the initial phase mediated by the bacteria and the later phase mediated by an endogenous mechanism possibly involving C-reactive protein. The differences in complement activation between animals with lethal or sublethal sepsis support the hypothesis that complement activation contributes to the lethal complications of sepsis. PMID:8406818

  11. Extended-spectrum and AmpC β-lactamase-producing Escherichia coli in broilers and people living and/or working on broiler farms: prevalence, risk factors and molecular characteristics.

    PubMed

    Huijbers, P M C; Graat, E A M; Haenen, A P J; van Santen, M G; van Essen-Zandbergen, A; Mevius, D J; van Duijkeren, E; van Hoek, A H A M

    2014-10-01

    The objectives of this study were to: estimate the prevalence of extended-spectrum β-lactamase (ESBL)- and AmpC β-lactamase-producing Escherichia coli carriage among broiler farmers, their family members and employees; identify and quantify risk factors for carriage, with an emphasis on contact with live broilers; and compare isolates from humans and broilers within farms with respect to molecular characteristics to gain insight into transmission routes. A cross-sectional prevalence study was conducted on 50 randomly selected Dutch broiler farms. Cloacal swabs were taken from 20 randomly chosen broilers. Faecal swabs were returned by 141 individuals living and/or working on 47 farms. ESBL/AmpC-producing E. coli were isolated and, for selected isolates, phylogenetic groups, plasmids and sequence types were determined. Questionnaires were used for risk factor analysis. All sampled farms were positive, with 96.4% positive pooled broiler samples. The human prevalence was 19.1%, with 14.3% and 27.1% among individuals having a low and a high degree of contact with live broilers, respectively. Five pairs of human-broiler isolates had identical genes, plasmid families and E. coli sequence types, showing clonal transmission. Furthermore, similar ESBL/AmpC genes on the same plasmid families in different E. coli sequence types in humans and broilers hinted at horizontal gene transfer. The prevalence among people on broiler farms was higher than in previous studies involving patients and the general population. Furthermore, an increased risk of carriage was shown among individuals having a high degree of contact with live broilers. The (relative) contribution of transmission routes that might play a role in the dissemination of ESBL/AmpC-encoding resistance genes to humans on broiler farms should be pursued in future studies. © The Author 2014. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For

  12. Photochromic conversion in a red/green cyanobacteriochrome from Synechocystis PCC6803: quantum yields in solution and photoswitching dynamics in living E. coli cells.

    PubMed

    Pennacchietti, Francesca; Losi, Aba; Xu, Xiu-ling; Zhao, Kai-hong; Gärtner, Wolfgang; Viappiani, Cristiano; Cella, Francesca; Diaspro, Alberto; Abbruzzetti, Stefania

    2015-02-01

    The protein encoded by the gene slr1393 from the cyanobacterium Synechocystis sp. PCC6803 (Slr1393) is composed of three GAF domains, a PAS domain, and a histidine kinase motif. The third GAF domain (referred to as GAF3) was previously characterized as the sole domain in this protein, being able to carry phycocyanobilin (PCB) as the chromophore and to accomplish photochemistry. GAF3 shows photochromicity, and is able to switch between a red-absorbing parental state (GAF3R, λmax = 649 nm) and a green-absorbing photoproduct state (GAF3G, λmax = 536 nm) upon appropriate irradiation. In this study we have determined the photochemical quantum yields for the interconversion between both forms using two methods: an "absolute" method and a reference-based control. The latter is a comparative procedure which exploits a well-characterized blue-light photoreceptor, YtvA from Bacillus subtilis, and the cyanobacterial phytochrome Cph1 as actinometers. The former is an ad hoc developed, four laser-based setup where two cw lasers provide the pump beams to induce photoswitching (red to green and green to red, respectively) and two cw lasers simultaneously monitor the appearance and disappearance of the two species. Interestingly, fit analysis of the recorded transient absorbance changes provided a quantum yield for the green → red conversion (≈0.3) at least three times larger than for the red → green conversion (≈0.08). These data are in agreement with the results from the comparative method documenting the usefulness of the 'direct' method developed here for quantum yields' determination. The light-induced switching capability of this photochromic protein allowed measuring the kinetics of GAF3 immobilized on a glass plate, and within living, overexpressing Escherichia coli cells.

  13. Methicillin-resistant Staphylococcus aureus and extended-spectrum and AmpC β-lactamase-producing Escherichia coli in broilers and in people living and/or working on organic broiler farms.

    PubMed

    Huijbers, Patricia M C; van Hoek, Angela H A M; Graat, Elisabeth A M; Haenen, Anja P J; Florijn, Alice; Hengeveld, Paul D; van Duijkeren, Engeline

    2015-03-23

    The aim of this study was to estimate the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) and extended-spectrum and AmpC β-lactamase (ESBL/AmpC)-producing Escherichia coli among broilers, and humans living and/or working on organic broiler farms; further characterise isolates; and compare these results with those from conventional farms. In the Netherlands, only 9 certified organic broiler farms were present. On 8 of these farms, 60 throat swabs and 20 cloacal swabs were taken per farm for MRSA and ESBL/AmpC-E. coli detection, respectively, at an average age of both 34 (T1) and 68 (T2) days. Faecal swabs and questionnaires were returned by 27 out of 36 humans. For selected ESBL/AmpC-producing E. coli isolates, phylogenetic groups, β-lactamase genes, plasmid families, and sequence types were determined. MRSA was not detected in broiler and human samples. ESBL/AmpC-producing E. coli were isolated from broilers on 7/8 farms at T1 and on all farms at T2. Furthermore, 3 farmers at T1, and 2 farmers and 1 family member at T2 were positive. Genes found in broilers and humans were almost exclusively blaCTX-M-1 and blaCMY-2. Given the high overall human ESBL/AmpC-prevalence (18.5%), which is similar to conventional farms, contact with live broilers is assumed a risk factor for carriage. Farm and sample-level prevalence at T1 are consistent with those from conventional farms. At T2, just before slaughter, sample-level prevalence of ESBL/AmpC-E. coli appears to have decreased (94.3% vs. 80%), which could have important consequences for contamination of retail meat. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Diarrheagenic Escherichia coli.

    PubMed

    Gomes, Tânia A T; Elias, Waldir P; Scaletsky, Isabel C A; Guth, Beatriz E C; Rodrigues, Juliana F; Piazza, Roxane M F; Ferreira, Luís C S; Martinez, Marina B

    2016-12-01

    Most Escherichia coli strains live harmlessly in the intestines and rarely cause disease in healthy individuals. Nonetheless, a number of pathogenic strains can cause diarrhea or extraintestinal diseases both in healthy and immunocompromised individuals. Diarrheal illnesses are a severe public health problem and a major cause of morbidity and mortality in infants and young children, especially in developing countries. E. coli strains that cause diarrhea have evolved by acquiring, through horizontal gene transfer, a particular set of characteristics that have successfully persisted in the host. According to the group of virulence determinants acquired, specific combinations were formed determining the currently known E. coli pathotypes, which are collectively known as diarrheagenic E. coli. In this review, we have gathered information on current definitions, serotypes, lineages, virulence mechanisms, epidemiology, and diagnosis of the major diarrheagenic E. coli pathotypes. Copyright © 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

  15. Histomorphometric evaluation of intestinal cellular immune responses in pigs immunized with live oral F4ac+ non-enterotoxigenic E. coli vaccine against postweaning colibacillosis

    PubMed Central

    Kovšca Janjatović, A.; Lacković, G.; Božić, F.; Kezić, D.; Popović, M.; Valpotić, H.; Harapin, I.; Pavižić, Ž.; Njari, B.; Valpotić, I.

    2010-01-01

    Enterotoxigenic Escherichia coli (ETEC) infection is the most common type of porcine postweaning colibacillosis (PWC). Among fimbriae of porcine ETEC strains the best studied family of fimbriae are the members of F4 adhesins, existing in at least three variants: ab, ac, ad. Active immunization against porcine PWC is difficult due to: i) ETEC strains are only one of the essential predisposing factors, ii) the success of vaccinal antigen uptake depends on the presence of enterocyte receptors for F4 adhesins, iii) the intestinal immune system may react with tolerance or hypersensitivity to the same antigens depending on the dose and form of the vaccinal immunogen, and iv) kinetics of the specific immune responses may be different in the case of F4 (earlier) and the other ETEC adhesins, particularly F18 (later). The aim of this study was to test the effectiveness of a live attenuated F4ac+ non-ETEC vaccine against porcine PWC by analyzing quantitative differences in the small intestinal lymphoid and myeloid cell subsets of immunized (with or without levamisole given as an adjuvant) vs control non-immunized pigs. Four week-old pigs were intragastrically immunized with a vaccine candidate F4ac + non-ETEC strain 2407 at day 0, challenged 7 days later with a virulent F4ac+ strain ETEC 11-800/1/94, euthanatized at day 13 and sampled for immunohistology. Non-immunized pigs received saline at day 0 and were processed as the principals. Immunophenotypes of lymphoid and myeloid cell subsets were demonstrated within jejunal and ileal mucosa by immunohistochemical avidinbiotin complex method and corresponding morphometric data were analyzed using software program Lucia G for digital image analyses. Monoclonal antibodies reactive with surface molecules on porcine immune cells such as CD3, CD45RA, CD45RC, CD21 and SWC3 enabled clear insight into distribution patterns and amount of these cells within the gut-associated lymphoid tissues (GALT) examined. The numbers of jejunal and

  16. Effect of feed supplementation with live yeast on the intestinal transcriptome profile of weaning pigs orally challenged with Escherichia coli F4.

    PubMed

    Trevisi, P; Latorre, R; Priori, D; Luise, D; Archetti, I; Mazzoni, M; D'Inca, R; Bosi, P

    2017-01-01

    The ability of live yeasts to modulate pig intestinal cell signals in response to infection with Escherichia coli F4ac (ETEC) has not been studied in-depth. The aim of this trial was to evaluate the effect of Saccharomyces cerevisiae CNCM I-4407 (Sc), supplied at different times, on the transcriptome profile of the jejunal mucosa of pigs 24 h after infection with ETEC. In total, 20 piglets selected to be ETEC-susceptible were weaned at 24 days of age (day 0) and allotted by litter to one of following groups: control (CO), CO+colistin (AB), CO+5×1010 colony-forming unit (CFU) Sc/kg feed, from day 0 (PR) and CO+5×1010 CFU Sc/kg feed from day 7 (CM). On day 7, the pigs were orally challenged with ETEC and were slaughtered 24 h later after blood sampling for haptoglobin (Hp) and C-reactive protein (CRP) determination. The jejunal mucosa was sampled (1) for morphometry; (2) for quantification of proliferation, apoptosis and zonula occludens (ZO-1); (3) to carry out the microarray analysis. A functional analysis was carried out using Gene Set Enrichment Analysis. The normalized enrichment score (NES) was calculated for each gene set, and statistical significance was defined when the False Discovery Rate % was <25 and P-values of NES were <0.05. The blood concentration of CRP and Hp, and the score for ZO-1 integrity on the jejunal villi did not differ between groups. The intestinal crypts were deeper in the AB (P=0.05) and the yeast groups (P<0.05) than in the CO group. Antibiotic treatment increased the number of mitotic cells in intestinal villi as compared with the control group (P<0.05). The PR group tended to increase the mitotic cells in villi and crypts and tended to reduce the cells in apoptosis as compared with the CM group. The transcriptome profiles of the AB and PR groups were similar. In both groups, the gene sets involved in mitosis and in mitochondria development ranked the highest, whereas in the CO group, the gene sets related to cell junction and anion

  17. E. Coli

    MedlinePlus

    ... Emergency Room? What Happens in the Operating Room? E. Coli KidsHealth > For Kids > E. Coli A A A What's in this article? What ... Doctor Do? What Can Kids Do? en español E. coli What Is It? E. coli is a common ...

  18. Monitoring redox-dependent contribution of lipids in Fourier transform infrared difference spectra of complex I from Escherichia coli.

    PubMed

    Hielscher, Ruth; Wenz, Tina; Stolpe, Stefan; Hunte, Carola; Friedrich, Thorsten; Hellwig, Petra

    2006-07-01

    Biochemical and crystallographic studies have shown that phospholipids are essential for the integrity and activity of membrane proteins. In the study presented here, we use electrochemically induced Fourier transform infrared (FTIR) spectroscopy to demonstrate variations occurring upon the presence and absence of lipids in NADH:ubiquinone oxidoreductase (complex I) from Escherchia coli by following the C=O vibration of the lipid molecule. Complex I is activated in the presence of lipids. Interestingly, in electrochemically induced FTIR difference spectra of complex I from E. coli, a new signal at 1744/1730 cm(-1) appears after addition of E. coli polar lipids, concomitant with the oxidized or reduced form, respectively. Absorbance spectra of liposomes from mixed lipids at different pH values demonstrate shifts for the carbonyl vibration depending on the environment. On this basis we suggest that lipids, though not redox active themselves, contribute in reaction-induced FTIR difference spectra, if a change occurs in the direct environment of the lipid during the observed reaction or coupled processes.

  19. Long-term feeding with Euglena gracilis cells modulates immune responses, oxidative balance and metabolic condition in Diplodon chilensis (Mollusca, Bivalvia, Hyriidae) exposed to living Escherichia coli.

    PubMed

    Bianchi, Virginia A; Castro, Juan M; Rocchetta, Iara; Nahabedian, Daniel E; Conforti, Visitación; Luquet, Carlos M

    2015-02-01

    We evaluated the modulating effect of long-term feeding with lyophilized Euglena gracilis cells on immune response, oxidative balance and metabolic condition of the freshwater mussel Diplodon chilensis. Mussels, previously fed with Scenedesmus vacuolatus (SV) or E. gracilis (EG) for 90 days, were challenged with an environmentally relevant concentration of Escherichia coli in water for 5 days, under feeding or starvation conditions. EG diet increased overall phagocytic activity and tissue hemocyte accumulation (gill and mantle), and favored hemocyte viability upon E. coli challenge. Tissular hemocyte accumulation, and humoral bacteriolytic activity and protein content were similarly stimulated by EG and E. coli, with no further effect when both stimuli were combined. Both, E. coli challenge and EG diet reduced gill bacteriolytic activity with respect to nonchallenged SV mussels, while no effect was observed in challenged EG mussels. Gill and digestive gland protein contents, along with digestive gland bacteriolytic activity were higher in EG than in SV mussels. Both SV and EG mussels showed increased gill mass upon E. coli challenge, while digestive gland mass was increased by bacterial challenge only in SV mussels. Bacterial challenge produced no effect on humoral reactive oxygen species levels of both groups. Total oxyradical scavenging capacity levels was reduced in challenged SV mussels but remained unaffected in EG ones. In general, EG diet decreased glutathione S-transferase and catalase activities in gill and digestive gland, compared with SV diet; but increased enzyme activity was evident in challenged mussels of both groups. Gill and digestive gland lipid peroxidation levels were higher in EG than in SV mussels but E. coli challenge had stronger effect on SV mussels. Adductor muscle RNA:DNA ratio was higher in EG mussels than in SV ones, and increased upon E. coli challenge in mussels of both groups. E. gracilis can be suggested as a nutritional and

  20. Modeling the effect of seasonal variation in ambient temperature on the transmission dynamics of a pathogen with a free-living stage: example of Escherichia coli O157:H7 in a dairy herd.

    PubMed

    Gautam, Raju; Bani-Yaghoub, Majid; Neill, William H; Döpfer, Dörte; Kaspar, Charles; Ivanek, Renata

    2011-10-01

    To explore the potential role of ambient temperature on infection transmission dynamics for pathogens, we used Escherichia coli O157:H7 in a dairy herd and the surrounding farm environment as a model system. For this system, we developed a mathematical model in which a Susceptible-Infectious-Susceptible (SIS) model of infection spread through the host population is coupled with a metapopulation model of E. coli O157:H7 free-living stage in the environment allowing bacterial growth to be influenced by ambient temperature. Model results indicate that seasonal variation in ambient temperature could have a considerable impact on pathogen populations in the environment, specifically on barn surfaces and in water troughs, and consequently on the prevalence of infection in the host population. Based on model assumptions, contaminated drinking water was the most important pathway of E. coli O157:H7 transmission to cattle. Sensitivity analysis indicated that water-borne transmission is amplified during the warmer months if the amount of standing drinking water available to the cattle herd is high. This is because warmer ambient temperature favors faster pathogen replication which when combined with slower water replacement-rate due to high amount of available standing water leads to a greater pathogen load in drinking water. These results offer a possible explanation of the seasonal variation in E. coli O157:H7 prevalence in cattle and suggest that improved drinking-water management could be used for control of this infection in cattle. Our study demonstrates how consideration of ambient temperature in transmission cycles of pathogens able to survive and grow in the environment outside the host could offer novel perspectives on the spread and control of infections caused by such pathogens.

  1. Comparison of multilocus sequence analysis and virulence genotyping of Escherichia coli from live birds, retail poultry meat, and human extraintestinal infection.

    PubMed

    Danzeisen, Jessica L; Wannemuehler, Yvonne; Nolan, Lisa K; Johnson, Timothy J

    2013-03-01

    To examine the correlations between virulence genotyping and multilocus sequence analysis of Escherichia coli from poultry and humans, 88 isolates were examined. The isolates were selected from a population of over 1000 based on their assignment to nine different virulence genotyping clusters. Clustering based on multilocus sequence analysis mostly correlated with virulence genotyping, although multilocus sequence analysis demonstrated higher discriminatory ability and greater reliability related to inferred phylogenetic relationships. No distinct patterns in host source were observed using inferred phylogeny through multilocus sequence analysis, indicating that human, avian, and retail meat isolates are diverse, and some belong to multiple shared clonal complexes. Clonal complexes with host source overlap included ST95 and ST23 and additional novel groups, underscoring the diversity of avian pathogenic E. coli and the potential importance of these novel groups as avian and zoonotic pathogens.

  2. Persistence of Escherichia coli O157:H7, Salmonella Newport, and Salmonella Poona in the gut of a free-living nematode, Caenorhabditis elegans, and transmission to progeny and uninfected nematodes.

    PubMed

    Kenney, Stephen J; Anderson, Gary L; Williams, Phillip L; Millner, Patricia D; Beuchat, Larry R

    2005-05-25

    A study was undertaken to determine the persistence of Escherichia coli O157:H7 and salmonellae in the gut of a free-living nematode, Caenorhabditis elegans, as affected by temperature and relative humidity and to determine if infected worms transmit Salmonella enterica serotype Newport to progeny and uninfected worms. Worms were fed cells of a non-pathogenic strain of E. coli (OP50), E. coli O157:H7, S. enterica serotype Newport, and S. enterica serotype Poona, followed by incubating at 4, 20, or 37 degrees C for up to 5 days. Initial populations of ingested pathogens significantly increased by up to 2.93 log(10) cfu/worm within 1 day at 20 degrees C on K agar and remained constant for an additional 4 days. When worms were placed on Bacto agar, populations of ingested pathogens remained constant at 4 degrees C, decreased significantly at 20 degrees C, and increased significantly at 37 degrees C within 3 days. Worms fed E. coli OP50 or S. Newport were incubated at 4 or 20 degrees C at relative humidities of 33%, 75%, or 98% to determine survival characteristics of ingested bacteria. Fewer cells of the pathogens survived incubation at 33% relative humidity compared to higher relative humidities. Populations of ingested E. coli OP50 and S. Newport decreased by up to 1.65 and 3.44 log(10) cfu/worm, respectively, in worms incubated at 20 degrees C and 33% relative humidity. Placement together on K agar of adult worms, labeled with green fluorescent protein (gfp) in the pharynx area, that had ingested gfp-labeled S. Newport and uninfected wild type worms resulted in transfer of the pathogen to gut of wild type worms. S. Newport was isolated from C. elegans two generations removed from exposure to the pathogen. Results of these studies show that C. elegans may serve as a temporary reservoir of foodborne pathogens, and could perhaps be a vector for contaminating preharvest fruits and vegetables, thus potentially increasing the risk of enteric infections associated with

  3. Genome-wide analysis of the response to nitric oxide in uropathogenic Escherichia coli CFT073

    PubMed Central

    Mehta, Heer H.; Liu, Yuxuan

    2015-01-01

    Uropathogenic Escherchia coli (UPEC) is the causative agent of urinary tract infections. Nitric oxide (NO) is a toxic water-soluble gas that is encountered by UPEC in the urinary tract. Therefore, UPEC probably requires mechanisms to detoxify NO in the host environment. Thus far, flavohaemoglobin (Hmp), an NO denitrosylase, is the only demonstrated NO detoxification system in UPEC. Here we show that, in E. coli strain CFT073, the NADH-dependent NO reductase flavorubredoxin (FlRd) also plays a major role in NO scavenging. We generated a mutant that lacks all known and candidate NO detoxification pathways (Hmp, FlRd and the respiratory nitrite reductase, NrfA). When grown and assayed anaerobically, this mutant expresses an NO-inducible NO scavenging activity, pointing to the existence of a novel detoxification mechanism. Expression of this activity is inducible by both NO and nitrate, and the enzyme is membrane-associated. Genome-wide transcriptional profiling of UPEC grown under anaerobic conditions in the presence of nitrate (as a source of NO) highlighted various aspects of the response of the pathogen to nitrate and NO. Several virulence-associated genes are upregulated, suggesting that host-derived NO is a potential regulator of UPEC virulence. Chromatin immunoprecipitation and sequencing was used to evaluate the NsrR regulon in CFT073. We identified 49 NsrR binding sites in promoter regions in the CFT073 genome, 29 of which were not previously identified in E. coli K-12. NsrR may regulate some CFT073 genes that do not have homologues in E. coli K-12. PMID:28348816

  4. Diarrhoeagenic Escherichia coli and other causes of childhood diarrhoea: a case-control study in children living in a wastewater-use area in Hanoi, Vietnam.

    PubMed

    Hien, Bui Thi Thu; Trang, Do Thuy; Scheutz, Flemming; Cam, Phung Dac; Mølbak, Kåre; Dalsgaard, Anders

    2007-08-01

    A case-control study was conducted to identify the aetiology of diarrhoeal diseases in pre-school children in a suburban area of Hanoi where the use of untreated wastewater in agriculture and aquaculture is a common practice. Stool specimens and clinical information were collected from 111 pairs of children with diarrhoea and healthy controls. A total of 73 cases (66 %) and 41 controls (36 %) had an enteric pathogen. The pathogens most often associated with diarrhoea were rotavirus (17 % of cases) and Entamoeba histolytica (15 %), followed by Shigella (5 %). Diarrhoeagenic Escherichia coli (DEC) was found in 23 % of both patients and controls. Characterization of DEC by serotyping, antimicrobial susceptibility test and PFGE showed that DEC represented by different pathotypes belonged to various serotypes. Except for three enterotoxigenic E. coli strains, typing by PFGE revealed no correlation between pathotype and serotype of DEC strains. This suggests a high prevalence of a variety of DEC subtypes in this area. For this particular region, vaccine development strategies targeting rotavirus and Shigella are likely to be of public health benefit, whereas the role of DEC and preventive measures need to be further elaborated.

  5. Association of Mu-containing plasmids with the Escherichia coli chromosome upon prophage induction

    PubMed Central

    Chaconas, George; Harshey, Rasika M.; Bukhari, Ahmad I.

    1980-01-01

    To determine the structure of a prophage-containing plasmid during Mu transposition, we have monitored the physical state of pSC101[unk]Mucts after thermoinduction. We have also examined the fate of a mini Mu plasmid constructed in vitro by deleting 27 kilobases from the center of the Mu prophage in pSC101[unk]Mucts. At various times after prophage induction, DNA was extracted from Mu or mini Mu plasmid-containing strains and subjected to electrophoresis in low concentration agarose gels followed by transfer of the DNA to nitrocellulose paper. Separate hybridization with 32P-labeled pSC101 and Mu DNA revealed the position of the plasmids and the replication of Mu DNA. At times after induction when Mu replication was clearly visible, Mu and mini Mu plasmids were found to migrate with Escherchia coli DNA. This Mu-specific association requires the phage coded A and B proteins. Electron microscopy has shown that some of the associated DNA is comprised of circular plasmid molecules which appear to be in contact with the chromosomal DNA. These structures may represent intermediates or end products of the replication-integration process. The finding that Mu and mini Mu plasmids do not give rise to any detectable excision products and apparently remain intact during Mu transposition supports our proposal that the predominant event after Mu induction is the replication of Mu DNA in situ to generate integrative intermediates. Images PMID:6246503

  6. E. Coli

    MedlinePlus

    ... of Your Teeth El cuidado de los dientes Video: Getting an X-ray E. Coli KidsHealth > For Kids > E. Coli Print A A A What's in ... recalls affecting contaminated vegetables or other products. But kids can ... inside. Don't swallow lake, ocean, or pool water. If the water contains ...

  7. [Resistant phenotypes of Escherichia coli strains responsible for urinary tract infection in the laboratory of the University Hospital Joseph Raseta Befelatanana, Antananarivo].

    PubMed

    Rakotovao-Ravahatra, Zafindrasoa Domoina; Randriatsarafara, Fidiniaina Mamy; Rasoanandrasana, Saïda; Raverohanta, Léa; Rakotovao, Andriamiadana Luc

    2017-01-01

    Urinary tract infection caused by Escherichia coli frequently occurs in the hospital environment. This study aims to describe resistant phenotypes of Escherichia coli strains to monitor their occurrence. We conducted a descriptive retrospective study of 102 Escherchia coli strains responsible for urinary tract infection in the laboratory of the University Hospital Joseph Raseta Befelatanana, Antananarivo from January 2014 to October 2016. Beta-lactam antibiotic resistance screening identified high-level penicillinases 50% (n=51), Escherichia coli producing extended-spectrum beta-lactamases (ESBLs) 22.5% (n=23), high-level cephalosporinases 14.7% (n=15), penicillinases low level 5.9% (n=6), wild type strains 5.9% (n=6) and a strain ofEscherichia coli emerging strain high-level resistance. Aminoglycosides resistance was identified in 58 (56.9%) wild type phenotype, 29 (28.4%) strains sensitive to amikacin and 15 (14.7%) resistant to all aminoglycosides. Fluoroquinolones resistance was identified in 52 (51%) wild type strains, 9 (8.8%) strains sensitive to ciprofloxacin and 41 (40.2%) resistant to all fluoroquinolones. Women (25, 7%) (p= 0.25, NS), patients more than 60 years (38.7%) (p=0.02), patients hospitalized in the Department of Nephrology (53.8%) (p=0.04), with urinary disorder and kidney disease (29, 7%) (p= 0.2, NS) were the most affected by E-ESBL. Based on high multidrug resistance in Escherichia coli strains guidelines for the empirical treatment of urinary tract infections need to be revised.

  8. Intestinal Colonization by Enterotoxigenic Escherichia coli.

    DTIC Science & Technology

    1980-09-01

    E . coli is mediated by specific types of pili. These pili are antigenic and can be used in diagnosing enterotoxigenic E . coli infections. They are also good protective antigens. When pregnant dams are vaccinated parenterally or orally with pili on live piliated bacteria, they secrete antibodies against the pili in their milk. Neonates suckling dams so vaccinated are passively protected against fatal challenge by enterotoxigenic E . coli . Pili are also good candidate protective antigens for the development of vaccines to protect by

  9. Application of sorting and next generation sequencing to study 5'-UTR influence on translation efficiency in Escherichia coli.

    PubMed

    Evfratov, Sergey A; Osterman, Ilya A; Komarova, Ekaterina S; Pogorelskaya, Alexandra M; Rubtsova, Maria P; Zatsepin, Timofei S; Semashko, Tatiana A; Kostryukova, Elena S; Mironov, Andrey A; Burnaev, Evgeny; Krymova, Ekaterina; Gelfand, Mikhail S; Govorun, Vadim M; Bogdanov, Alexey A; Sergiev, Petr V; Dontsova, Olga A

    2016-11-29

    Yield of protein per translated mRNA may vary by four orders of magnitude. Many studies analyzed the influence of mRNA features on the translation yield. However, a detailed understanding of how mRNA sequence determines its propensity to be translated is still missing. Here, we constructed a set of reporter plasmid libraries encoding CER fluorescent protein preceded by randomized 5' untranslated regions (5'-UTR) and Red fluorescent protein (RFP) used as an internal control. Each library was transformed into Escherchia coli cells, separated by efficiency of CER mRNA translation by a cell sorter and subjected to next generation sequencing. We tested efficiency of translation of the CER gene preceded by each of 48 natural 5'-UTR sequences and introduced random and designed mutations into natural and artificially selected 5'-UTRs. Several distinct properties could be ascribed to a group of 5'-UTRs most efficient in translation. In addition to known ones, several previously unrecognized features that contribute to the translation enhancement were found, such as low proportion of cytidine residues, multiple SD sequences and AG repeats. The latter could be identified as translation enhancer, albeit less efficient than SD sequence in several natural 5'-UTRs.

  10. Application of sorting and next generation sequencing to study 5΄-UTR influence on translation efficiency in Escherichia coli

    PubMed Central

    Evfratov, Sergey A.; Osterman, Ilya A.; Komarova, Ekaterina S.; Pogorelskaya, Alexandra M.; Rubtsova, Maria P.; Zatsepin, Timofei S.; Semashko, Tatiana A.; Kostryukova, Elena S.; Mironov, Andrey A.; Burnaev, Evgeny; Krymova, Ekaterina; Gelfand, Mikhail S.; Govorun, Vadim M.; Bogdanov, Alexey A.; Dontsova, Olga A.

    2017-01-01

    Abstract Yield of protein per translated mRNA may vary by four orders of magnitude. Many studies analyzed the influence of mRNA features on the translation yield. However, a detailed understanding of how mRNA sequence determines its propensity to be translated is still missing. Here, we constructed a set of reporter plasmid libraries encoding CER fluorescent protein preceded by randomized 5΄ untranslated regions (5΄-UTR) and Red fluorescent protein (RFP) used as an internal control. Each library was transformed into Escherchia coli cells, separated by efficiency of CER mRNA translation by a cell sorter and subjected to next generation sequencing. We tested efficiency of translation of the CER gene preceded by each of 48 natural 5΄-UTR sequences and introduced random and designed mutations into natural and artificially selected 5΄-UTRs. Several distinct properties could be ascribed to a group of 5΄-UTRs most efficient in translation. In addition to known ones, several previously unrecognized features that contribute to the translation enhancement were found, such as low proportion of cytidine residues, multiple SD sequences and AG repeats. The latter could be identified as translation enhancer, albeit less efficient than SD sequence in several natural 5΄-UTRs. PMID:27899632

  11. Comparison of a live attenuated Salmonella Enteritidis vaccine candidate secreting Escherichia coli heat-labile enterotoxin B subunit with a commercial vaccine for efficacy of protection against internal egg contamination by Salmonella in hens.

    PubMed

    Nandre, Rahul M; Eo, Seong Kug; Park, Sang Youel; Lee, John Hwa

    2015-07-01

    This study compared a new live attenuated Salmonella Enteritidis vaccine candidate secreting Escherichia coli heat-labile enterotoxin B subunit (SE-LTB) with a commercial Salmonella Enteritidis (SE) vaccine for efficacy of protection against SE infection in laying hens. Chickens were divided into 3 groups of 20 each. Group A chickens were inoculated orally with phosphate-buffered saline and served as controls, group B chickens were inoculated orally with the vaccine candidate, and group C chickens were inoculated intramuscularly with a commercial vaccine, the primary inoculation in groups B and C being at 10 wk of age and the booster at 16 wk. Groups B and C showed significantly higher titers of plasma immunoglobulin G, intestinal secretory immunoglobulin A, and egg yolk immunoglobulin Y antibodies compared with the control group, and both vaccinated groups showed a significantly elevated cellular immune response. After virulent challenge, group B had significantly lower production of thin-shelled and/or malformed eggs and a significantly lower rate of SE contamination of eggs compared with the control group. Furthermore, the challenge strain was detected significantly less in all of the examined organs of group B compared with the control group. Group C had lower gross lesion scores only in the spleen and had lower bacterial counts only in the spleen, ceca, and ovary. These findings indicate that vaccination with the SE-LTB vaccine candidate can efficiently reduce internal egg and internal organ contamination by Salmonella and has advantages over the commercial vaccine.

  12. Live Healthy, Live Longer

    MedlinePlus

    ... Human Services. More Health News on: Exercise and Physical Fitness Health Screening Healthy Living Recent Health News Related MedlinePlus Health Topics Exercise and Physical Fitness Health Screening Healthy Living About MedlinePlus Site Map ...

  13. 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…

  14. 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…

  15. Engineering living functional materials.

    PubMed

    Chen, Allen Y; Zhong, Chao; Lu, Timothy K

    2015-01-16

    Natural materials, such as bone, integrate living cells composed of organic molecules together with inorganic components. This enables combinations of functionalities, such as mechanical strength and the ability to regenerate and remodel, which are not present in existing synthetic materials. Taking a cue from nature, we propose that engineered 'living functional materials' and 'living materials synthesis platforms' that incorporate both living systems and inorganic components could transform the performance and the manufacturing of materials. As a proof-of-concept, we recently demonstrated that synthetic gene circuits in Escherichia coli enabled biofilms to be both a functional material in its own right and a materials-synthesis platform. To demonstrate the former, we engineered E. coli biofilms into a chemical-inducer-responsive electrical switch. To demonstrate the latter, we engineered E. coli biofilms to dynamically organize biotic-abiotic materials across multiple length scales, template gold nanorods, gold nanowires, and metal/semiconductor heterostructures, and synthesize semiconductor nanoparticles (Chen, A. Y. et al. (2014) Synthesis and patterning of tunable multiscale materials with engineered cells. Nat. Mater. 13, 515-523.). Thus, tools from synthetic biology, such as those for artificial gene regulation, can be used to engineer the spatiotemporal characteristics of living systems and to interface living systems with inorganic materials. Such hybrids can possess novel properties enabled by living cells while retaining desirable functionalities of inorganic systems. These systems, as living functional materials and as living materials foundries, would provide a radically different paradigm of materials performance and synthesis-materials possessing multifunctional, self-healing, adaptable, and evolvable properties that are created and organized in a distributed, bottom-up, autonomously assembled, and environmentally sustainable manner.

  16. Engineering Living Functional Materials

    PubMed Central

    2016-01-01

    Natural materials, such as bone, integrate living cells composed of organic molecules together with inorganic components. This enables combinations of functionalities, such as mechanical strength and the ability to regenerate and remodel, which are not present in existing synthetic materials. Taking a cue from nature, we propose that engineered ‘living functional materials’ and ‘living materials synthesis platforms’ that incorporate both living systems and inorganic components could transform the performance and the manufacturing of materials. As a proof-of-concept, we recently demonstrated that synthetic gene circuits in Escherichia coli enabled biofilms to be both a functional material in its own right and a materials-synthesis platform. To demonstrate the former, we engineered E. coli biofilms into a chemical-inducer-responsive electrical switch. To demonstrate the latter, we engineered E. coli biofilms to dynamically organize biotic-abiotic materials across multiple length scales, template gold nanorods, gold nanowires, and metal/semiconductor heterostructures, and synthesize semiconductor nanoparticles (Chen, A. Y. et al. (2014) Synthesis and patterning of tunable multiscale materials with engineered cells. Nat. Mater.13, 515–523.). Thus, tools from synthetic biology, such as those for artificial gene regulation, can be used to engineer the spatiotemporal characteristics of living systems and to interface living systems with inorganic materials. Such hybrids can possess novel properties enabled by living cells while retaining desirable functionalities of inorganic systems. These systems, as living functional materials and as living materials foundries, would provide a radically different paradigm of materials performance and synthesis–materials possessing multifunctional, self-healing, adaptable, and evolvable properties that are created and organized in a distributed, bottom-up, autonomously assembled, and environmentally sustainable manner. PMID

  17. Attenuated Shigella flexneri 2a ΔguaBA Strain CVD 1204 Expressing Enterotoxigenic Escherichia coli (ETEC) CS2 and CS3 Fimbriae as a Live Mucosal Vaccine against Shigella and ETEC Infection

    PubMed Central

    Altboum, Zeev; Barry, Eileen M.; Losonsky, Genevieve; Galen, James E.; Levine, Myron M.

    2001-01-01

    To construct a prototype hybrid vaccine against Shigella and enterotoxigenic Escherichia coli (ETEC), the genes encoding the production of ETEC CS2 and CS3 fimbriae were isolated and expressed in attenuated Shigella flexneri 2a guaBA strain CVD 1204. The CS2 cotA to -D genes, isolated from ETEC strain C91F, and the CS3 cstA to -H genes, subcloned from plasmid pCS100, were cloned into ∼15-copy-number-stabilized pGA1 behind the osmotically regulated ompC promoter, resulting in high expression of both fimbriae. Under nonselective in vitro growth conditions, pGA1-CS2 and pGA1-CS3 were stable in CVD 1204, exhibiting a plasmid loss of only approximately 1% per duplication. Expression of CS2 and CS3 reduced the invasiveness of Shigella for HeLa cells and slowed the intracellular growth rate. Guinea pigs immunized intranasally with CVD 1204(pGA1-CS2) or CVD 1204(pGA1-CS3), or with a mixture of these strains, developed secretory immunoglobulin A (IgA) in tears and serum IgG antibodies against Shigella lipopolysaccharide, CS2, and CS3 antigens. Moreover, the animals were protected against keratoconjunctivitis following conjunctival challenge with virulent S. flexneri 2a strain 2457T. Animals immunized with Shigella expressing CS2 or CS3 developed serum antibodies that agglutinated Shigella as well as an ETEC strain bearing the homologous fimbriae, whereas animals immunized with combined CVD 1204(pGA1-CS2) and CVD 1204(pGA1-CS3) developed antibodies that agglutinated all three test strains. These observations support the feasibility of a multivalent vaccine against shigellosis and ETEC diarrhea consisting of multiple Shigella live vectors expressing relevant ETEC antigens. PMID:11292735

  18. Intimin, tir, and shiga toxin 1 do not influence enteropathogenic responses to shiga toxin-producing Escherichia coli in bovine ligated intestinal loops.

    PubMed

    Stevens, Mark P; Marchès, Olivier; Campbell, June; Huter, Veronika; Frankel, Gad; Phillips, Alan D; Oswald, Eric; Wallis, Timothy S

    2002-02-01

    Shiga toxin-producing Escherchia coli (STEC) comprises a group of attaching and effacing (A/E) enteric pathogens of animals and humans. Natural and experimental infection of calves with STEC may result in acute enteritis or subclinical infection, depending on serotype- and host-specific factors. To quantify intestinal secretory and inflammatory responses to STEC in the bovine intestine, serotypes that are associated with human disease (O103:H2 and O157:H7) were introduced into ligated mid-ileal loops in gnotobiotic and conventional calves, and fluid accumulation and recruitment of radiolabeled neutrophils were measured after 12 h. STEC serotype O103:H2, but not serotype O157:H7, elicited strong enteropathogenic responses. To determine if the inflammatory response to STEC O103:H2 in calves requires Shiga toxin 1 or intimate bacterial attachment to the intestinal epithelium, defined mutations were made in the stx1, eae, and tir genes. Our data indicate that some STEC induce intestinal inflammatory responses in calves by a mechanism that is independent of A/E-lesion formation, intimin, or Shiga toxin 1. This may have implications for strategies to reduce STEC carriage in cattle.

  19. Intimin, Tir, and Shiga Toxin 1 Do Not Influence Enteropathogenic Responses to Shiga Toxin-Producing Escherichia coli in Bovine Ligated Intestinal Loops

    PubMed Central

    Stevens, Mark P.; Marchès, Olivier; Campbell, June; Huter, Veronika; Frankel, Gad; Phillips, Alan D.; Oswald, Eric; Wallis, Timothy S.

    2002-01-01

    Shiga toxin-producing Escherchia coli (STEC) comprises a group of attaching and effacing (A/E) enteric pathogens of animals and humans. Natural and experimental infection of calves with STEC may result in acute enteritis or subclinical infection, depending on serotype- and host-specific factors. To quantify intestinal secretory and inflammatory responses to STEC in the bovine intestine, serotypes that are associated with human disease (O103:H2 and O157:H7) were introduced into ligated mid-ileal loops in gnotobiotic and conventional calves, and fluid accumulation and recruitment of radiolabeled neutrophils were measured after 12 h. STEC serotype O103:H2, but not serotype O157:H7, elicited strong enteropathogenic responses. To determine if the inflammatory response to STEC O103:H2 in calves requires Shiga toxin 1 or intimate bacterial attachment to the intestinal epithelium, defined mutations were made in the stx1, eae, and tir genes. Our data indicate that some STEC induce intestinal inflammatory responses in calves by a mechanism that is independent of A/E-lesion formation, intimin, or Shiga toxin 1. This may have implications for strategies to reduce STEC carriage in cattle. PMID:11796630

  20. 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

  1. Assisted Living

    MedlinePlus

    ... but they don't need full-time nursing care. Some assisted living facilities are part of retirement ... change. Assisted living costs less than nursing home care. It is still fairly expensive. Older people or ...

  2. Biodegradation of aromatic compounds by Escherichia coli.

    PubMed

    Díaz, E; Ferrández, A; Prieto, M A; García, J L

    2001-12-01

    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.

  3. 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

  4. Topical Application of Escherichia coli-Vectored Vaccine as a Simple Method for Eliciting Protective Immunity

    PubMed Central

    Zhang, Jianfeng; Shi, Zhongkai; Kong, Fan-kun; Jex, Edward; Huang, Zhigang; Watt, James M.; Van Kampen, Kent R.; Tang, De-chu C.

    2006-01-01

    We report here that animals can be protected against lethal infection by Clostridium tetani cells and Bacillus anthracis spores following topical application of intact particles of live or γ-irradiated Escherichia coli vectors overproducing tetanus and anthrax antigens, respectively. Cutaneous γδT cells were rapidly recruited to the administration site. Live E. coli cells were not found in nonskin tissues after topical application, although fragments of E. coli DNA were disseminated transiently. Evidence suggested that intact E. coli particles in the outer layer of skin may be disrupted by a γδT-cell-mediated innate defense mechanism, followed by the presentation of E. coli ligand-adjuvanted intravector antigens to the immune system and rapid degradation of E. coli components. The nonreplicating E. coli vector overproducing an exogenous immunogen may foster the development of a new generation of vaccines that can be manufactured rapidly and administered noninvasively in a wide variety of disease settings. PMID:16714593

  5. Phénotypes de résistance des souches d’Escherichia coli responsables d’infection urinaire au laboratoire du Centre Hospitalo-Universitaire de Befelatanana Antananarivo

    PubMed Central

    Rakotovao-Ravahatra, Zafindrasoa Domoina; Randriatsarafara, Fidiniaina Mamy; Rasoanandrasana, Saïda; Raverohanta, Léa; Rakotovao, Andriamiadana Luc

    2017-01-01

    Introduction I’infection urinaire à Escherichia coli est fréquente en milieu hospitalier. Cette étude se propose de décrire les différents phénotypes de résistance des souches d’Escherichia coli afin de surveiller leur émergence. Méthodes Il s’agit d’une étude rétrospective de type descriptif de 102 souches d’Escherchia coli responsables d’infection urinaire sur une période allant du mois de Janvier 2014 au mois d’Octobre 2016 au Laboratoire du Centre Hospitalo-Universitaire Befelatanana Antananarivo. Résultats La résistance aux béta-lactamines a identifié des pénicillinases de haut niveau 50% (n=51), des Escherichia coli sécrétrices de Béta-Lactamase à Spectre Etendu E-BLSE 22,5% (n=23), des céphalosporinases de haut niveau 14,7% (n=15), des pénicillinases de bas niveau 5,9% (n=6), des souches sauvages 5,9% (n=6) et une souche d’Escherichia coli hautement résistante émergente. La résistance aux aminosides a concerné 58 (56,9%) phénotypes sauvages, 29 (28,4%) souches sensibles à l’amikacine et 15 (14,7%) résistants à tous les aminosides. La résistance aux fluoroquinolones a identifiée 52 (51%) souches sauvages, 9 (8,8%) souches sensibles à la ciprofloxacine et 41 (40,2%) résistantes à tous les fluoroquinolones. Les femmes (25, 7%) (p= 0,25, NS), les sujets de plus de 60 ans (38,7%) (p=0,02), les sujets hospitalisés dans le service de néphrologie (53,8%) (p=0,04), ayant présenté des troubles urinaires et rénaux (29, 7%) (p= 0,2, NS), ont été les plus affectés par les E-BLSE. Conclusion La multi-résistance élevée des souches d’Escherichia coli interpelle sur une révision du traitement empirique des infections urinaires. PMID:28674559

  6. Escherichia coli biofilms

    PubMed Central

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

    2008-01-01

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

  7. A comprehensive library of fluorescent transcriptional reporters for Escherichia coli.

    PubMed

    Zaslaver, Alon; Bren, Anat; Ronen, Michal; Itzkovitz, Shalev; Kikoin, Ilya; Shavit, Seagull; Liebermeister, Wolfram; Surette, Michael G; Alon, Uri

    2006-08-01

    E. coli is widely used for systems biology research; there exists a need, however, for tools that can be used to accurately and comprehensively measure expression dynamics in individual living cells. To address this we present a library of transcriptional fusions of gfp to each of about 2,000 different promoters in E. coli K12, covering the great majority of the promoters in the organism. Each promoter fusion is expressed from a low-copy plasmid. We demonstrate that this library can be used to obtain highly accurate dynamic measurements of promoter activity on a genomic scale, in a glucose-lactose diauxic shift experiment. The library allowed detection of about 80 previously uncharacterized transcription units in E. coli, including putative internal promoters within previously known operons, such as the lac operon. This library can serve as a tool for accurate, high-resolution analysis of transcription networks in living E. coli cells.

  8. Pathogenic Escherichia coli

    USDA-ARS?s Scientific Manuscript database

    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...

  9. 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...

  10. Escherichia coli isolated from feces of brown bears (Ursus arctos) have a lower prevalence of human extraintestinal pathogenic E. coli virulence-associated genes.

    PubMed

    Vadnov, Maruša; Barbič, Damjana; Žgur-Bertok, Darja; Erjavec, Marjanca Starčič

    2017-01-01

    Eighty-six Escherichia coli strains from feces of either wild brown bears or those living in a zoo were screened for phylogenetic groups using the revisited Clermont phylotyping method and the prevalence of 24 virulence-associated genes (VAGs) of extraintestinal pathogenic E. coli (ExPEC). Our results showed that most strains of E. coli in bears belonged to phylogenetic groups III/IV/V (29%) and B1 (26%). Only half of the tested VAGs were found in the E. coli bear strains, with fimH present in 72%, ompT in 63%, and kpsMT in 43% of the strains. When the data obtained on the fecal E. coli strains from brown bears were compared with the data obtained on 90 fecal E. coli strains from healthy humans, there were significant differences in E. coli population structures between both hosts.

  11. Living Laboratories

    ERIC Educational Resources Information Center

    Mules, B. R.

    1976-01-01

    Presented is a review of various methods of keeping live animals, including scorpions, spiders, crabs, crayfish, shrimp, ants, fish, mice, and birds, as well as plants as a school science project/display. (SL)

  12. Assisted Living

    MedlinePlus

    ... Recreational activities Security Transportation How to Choose a Facility A good match between a facility and a resident's needs depends as much on the philosophy and services of the assisted living facility as it does on the quality of care. ...

  13. Greener Living

    EPA Pesticide Factsheets

    Learn about how to live a more environmentally friendly life by reducing your environmental footprint, enhancing sustainability, using clean energy, water efficiency, composting, selecting a fuel efficient vehicle, and reducing waste.

  14. Living Laboratories

    ERIC Educational Resources Information Center

    Mules, B. R.

    1976-01-01

    Presented is a review of various methods of keeping live animals, including scorpions, spiders, crabs, crayfish, shrimp, ants, fish, mice, and birds, as well as plants as a school science project/display. (SL)

  15. Healthy Living

    MedlinePlus

    ... changes to your lifestyle. By taking steps toward healthy living, you can help reduce your risk of ... Get the screening tests you need Maintain a healthy weight Eat a variety of healthy foods, and ...

  16. Bachelor Living

    ERIC Educational Resources Information Center

    Germer, Sondra

    1974-01-01

    Male high school students in a Bachelor Living Class observed methods of child care including bottle feeding, spoon feeding, changing diapers, and method of holding. The purpose was for the students to grasp a better understanding of child development. (EK)

  17. [Acute diarrheal disease caused by enteropathogenic Escherichia coli in Colombia].

    PubMed

    Gómez-Duarte, Oscar G

    2014-10-01

    Intestinal Escherichia coli pathogens are leading causes of acute diarrheal disease in children less than 5 years in Latin America, Africa and Asia and a leading cause of death in children living in poorest communities in Africa and South East Asia. Studies on the role of E. coli pathogens in childhood diarrhea in Colombia and other countries in Latin America are limited due to the lack of detection assays in clinical laboratories at the main urban medical centers. Recent studies report that enterotoxigenic E. coli is the most common E. coli pathogens associated with diarrhea in children less than 5 years of age. Other E. coli pathotypes have been detected in children with diarrhea including enteropathogenic, enteroaggregative, shiga-toxin producing and diffusely adherent E. coli. It was also found that meat and vegetables at retail stores are contaminated with Shiga-toxin producing E. coli and enteroaggregative E. coli, suggesting that food products are involved in transmission and infection of the susceptible host. More studies are necessary to evaluate the mechanisms of transmission, the impact on the epidemiology of diarrheal disease, and management strategies and prevention of these pathogens affecting the pediatric population in Colombia.

  18. Escherichia coli early-onset sepsis: trends over two decades.

    PubMed

    Mendoza-Palomar, Natalia; Balasch-Carulla, Milena; González-Di Lauro, Sabina; Céspedes, Maria Concepció; Andreu, Antònia; Frick, Marie Antoinette; Linde, Maria Ángeles; Soler-Palacin, Pere

    2017-08-02

    Escherichia coli early-onset sepsis (EOS) is an important cause of mortality and morbidity in neonates, especially in preterm and very low birth weight (VLBW) newborns. The aim of our study was to evaluate potential changes in the clinical and microbiological characteristics of E. coli EOS in our setting. Epidemiological, clinical, and microbiological data from all neonates with proven E. coli EOS from January 1994 to December 2014 were retrospectively collected in a single tertiary care hospital in Barcelona (Spain). Seventy-eight E. coli EOS cases were analyzed. A slight increase in the incidence of E. coli EOS was observed during the study period. VLBW newborns remained the group with higher incidence (10.4 cases per 1000 live births) and mortality (35.3%). Systematic use of PCR increased E. coli EOS diagnosis, mainly in the term newborn group. There was an increase in resistant E. coli strains causing EOS, with especially high resistance to ampicillin and gentamicin (92.8 and 28.6%, respectively). Nonetheless, resistant strains were not associated with poorer clinical outcomes. There is an urgent need to reconsider the empirical therapy used in neonatal EOS, particularly in VLBW newborns. What is Known: • E. coli early-onset sepsis (EOS) and E. coli resistant strains have been described as overall stable but increasing in VLBW neonates (< 1.500 g) in previous studies. What is New: • Our study shows an increasing incidence of E. coli EOS in all age groups, overruling group B Streptoccocus for the last 10 years. E. coli resistant strains also increased equally in all age groups, with high resistance rates to our first line antibiotics (ampicillin and gentamicin). • Empiric antibiotic therapy of EOS, mainly in VLBW newborns, should be adapted to this new scenario.

  19. Comparison of three patterns of feed supplementation with live Saccharomyces cerevisiae yeast on postweaning diarrhea, health status, and blood metabolic profile of susceptible weaning pigs orally challenged with Escherichia coli F4ac.

    PubMed

    Trevisi, P; Colombo, M; Priori, D; Fontanesi, L; Galimberti, G; Calò, G; Motta, V; Latorre, R; Fanelli, F; Mezzullo, M; Pagotto, U; Gherpelli, Y; D'Inca, R; Bosi, P

    2015-05-01

    The development of effective feeding strategies to reduce the detrimental effect of enterotoxigenic F4ac (ETEC) plays a crucial role in reducing the occurrence of therapeutic intervention with antibiotics in livestock. The ability of CNCM I-4407 (SCC), supplied in different patterns to counteract ETEC infection in weaned pigs, was evaluated. Fifty pigs weaned at 24 d were then divided into 5 groups: control (CO), CO + colistin (AB), CO + 5 × 10(10) cfu of SCC/ kg feed, from d 0 to 21 (PR), CO + 5 × 10(10) cfu of SCC/ kg feed from d 7 to 11 (CM), and CO + 1 shot of 2 × 10(11) cfu of SCC when the first diarrhea appeared (CU). On d 7 postweaning, all the pigs were orally challenged with 10(8) cfu of ETEC. Blood samples were taken from the pigs (d 7, 8, 12, and 21) while the fecal excretion of ETEC was assessed on d 7 and 10. Fecal consistency was scored from 12 h before infection to 144 h postinfection (p.i.). On d 21, the pigs were sacrificed. The in vitro adhesion test on the intestinal villi confirmed individual susceptibility to ETEC, excluding the presence of resistant pigs. Growth performance did not differ between the treatments. Mortality was reduced in the AB group (P< 0.01) and, marginally, in the PR group (P = 0.089) when compared to the CO group. The CO group had a higher fecal score than AB in the period of observation (from P = 0.01 to P< 0.001). Yeast administration reduced the fecal score when compared to the CO group 12 and 48 h p.i. (P = 0.04). Total IgA never differed among the treatments, but the ETEC-specific IgA concentration was lower in the AB group than in CO (P = 0.04) at d 12. Four days p.i., the pigs fed live yeast had reduced ETEC excretion compared with the CO pigs (P = 0.05). Blood concentrations of dodecenoyl-L-carnitine (P < 0.01), glutaryl-L-carnitine/hydroxyhex¬anoyl-L-carnitine, phosphatidylcholine diacyl and phosphatidylcholine diacyl (P = 0.01 and P< 0.01, respectively), and α-amino adipic acid (P < 0.01) were reduced in the

  20. E. Coli Infections

    MedlinePlus

    ... type causes travelers' diarrhea. The worst type of E. coli causes bloody diarrhea, and can sometimes cause kidney failure and even death. These problems are most likely to occur in children and ...

  1. Adhesive threads of extraintestinal pathogenic Escherichia coli.

    PubMed

    Antão, Esther-Maria; Wieler, Lothar H; Ewers, Christa

    2009-12-10

    The ability to adhere to host surfaces is by far the most vital step in the successful colonization by microbial pathogens. Colonization begins with the attachment of the bacterium to receptors expressed by cells forming the lining of the mucosa. Long hair like extracellular appendages called fimbriae, produced by most Gram-negative pathogens, mediate specific attachment to the epithelial cell surface. Associated with the fimbriae is a protein called an adhesin, which directs high-affinity binding to specific cell surface components. In the last couple of years, an enormous amount of research has been undertaken that deals with understanding how bacterial pathogens adhere to host cells. E. coli in all probability is one of the best studied free-living organisms. A group of E. coli called Extraintestinal pathogenic E. coli (ExPEC) including both human and animal pathogens like Uropathogenic E. coli (UPEC), Newborn meningitic E. coli (NMEC) and Avian pathogenic E. coli (APEC), have been found to harbour many fimbriae including Type 1 fimbriae, P fimbriae, curli fibres, S fimbriae, F1C fimbriae, Dr fimbriae, afimbrial adhesins, temperature-sensitive haemagglutinin and many novel adhesin gene clusters that have not yet been characterized. Each of these adhesins is unique due to the recognition of an adhesin-specific receptor, though as a group these adhesins share common genomic organization. A newly identified putative adhesin temporarily termed ExPEC Adhesin I, encoded by gene yqi, has been recently found to play a significant role in the pathogenesis of APEC infection, thus making it an interesting candidate for future research. The aim of this review is to describe the role of ExPEC adhesins during extraintestinal infections known till date, and to suggest the idea of investigating their potential role in the colonization of the host gut which is said to be a reservoir for ExPEC.

  2. In vitro Effects of Methylprednisolone Sodium Succinate and E. coli Organisms on Neutrophils in Baboon Blood.

    DTIC Science & Technology

    1977-10-11

    depresses glucose metabolism of leukocytes or adversely affects neutrophil survival, or whether it modifies the mortality rate of live E . coli in...exert no detrimental influences on glucose utilization or survival of neutrophils in the absence or presence of E . coli organisms in concentrations of...4.2x 10 to the 7th power and 2.3x 10 to the 8th power organisms/ml blood. E . coli organisms, however, increase neutrophil mortality rate and glucose

  3. 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

  4. Uropathogenic Escherichia coli are less likely than paired fecal E. coli to have CRISPR loci.

    PubMed

    Dang, Trang Nguyen Doan; Zhang, Lixin; Zöllner, Sebastian; Srinivasan, Usha; Abbas, Khadija; Marrs, Carl F; Foxman, Betsy

    2013-10-01

    CRISPRs (Clustered Regularly Interspaced Short Palindromic Repeats) are short fragments of DNA that act as an adaptive immune system protecting bacteria against invasion by phages, plasmids or other forms of foreign DNA. Bacteria without a CRISPR locus may more readily adapt to environmental changes by acquiring foreign genetic material. Uropathogenic Escherichia coli (UPEC) live in a number of environments suggesting an ability to rapidly adapt to new environments. If UPEC are more adaptive than commensal E. coli we would expect that UPEC would have fewer CRISPR loci, and--if loci are present--that they would harbor fewer spacers than CRISPR loci in fecal E. coli. We tested this in vivo by comparing the number of CRISPR loci and spacers, and sensitivity to antibiotics (resistance is often obtained via plasmids) among 81 pairs of UPEC and fecal E. coli isolated from women with urinary tract infection. Each pair included one uropathogen and one commensal (fecal) sample from the same female patient. Fecal isolates had more repeats (p=0.009) and more unique spacers (p<0.0001) at four CRISPR loci than uropathogens. By contrast, uropathogens were more likely than fecal E. coli to be resistant to ampicillin, cefazolin and trimethoprim/sulfamethoxazole. However, no consistent association between CRISPRs and antibiotic resistance was identified. To our knowledge, this is the first study to compare fecal E. coli and pathogenic E. coli from the same individuals, and to test the association of CRISPR loci with antibiotic resistance. Our results suggest that the absence of CRISPR loci may make UPEC more susceptible to infection by phages or plasmids and allow them to adapt more quickly to various environments. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Countryside Live!

    ERIC Educational Resources Information Center

    Best, Andrew; Richardson, Gary

    2006-01-01

    The "Countryside Live!" events, organised by the Countryside Foundation for Education (CFE), provide a unique opportunity for urban children to explore a whole new area of possibilities and learning, through becoming aware at first-hand of what goes on in the countryside. The event at Staunton Country Park, Havant, Hampshire, which took…

  6. Independent Living.

    ERIC Educational Resources Information Center

    Nathanson, Jeanne H., Ed.

    1994-01-01

    This issue of "OSERS" addresses the subject of independent living of individuals with disabilities. The issue includes a message from Judith E. Heumann, the Assistant Secretary of the Office of Special Education and Rehabilitative Services (OSERS), and 10 papers. Papers have the following titles and authors: "Changes in the…

  7. Outdoor Living.

    ERIC Educational Resources Information Center

    Cotter, Kathy

    Course objectives and learning activities are contained in this curriculum guide for a 16-week home economics course which teaches cooking and sewing skills applicable to outdoor living. The course goals include increasing male enrollment in the home economics program, developing students' self-confidence and ability to work in groups, and…

  8. Retiring Lives

    ERIC Educational Resources Information Center

    Carnell, Eileen, Ed.; Lodge, Caroline, Ed.

    2009-01-01

    "Retiring Lives" presents fourteen personal real life stories from people at various stages of retiring. Each author recounts their own story about retiring, bringing together many aspects of the experiences: the social, psychological and practical. These inspirational and illustrated stories will encourage the reader to hold up these…

  9. Retiring Lives

    ERIC Educational Resources Information Center

    Carnell, Eileen, Ed.; Lodge, Caroline, Ed.

    2009-01-01

    "Retiring Lives" presents fourteen personal real life stories from people at various stages of retiring. Each author recounts their own story about retiring, bringing together many aspects of the experiences: the social, psychological and practical. These inspirational and illustrated stories will encourage the reader to hold up these…

  10. Living History

    ERIC Educational Resources Information Center

    Walsh, Mark

    2005-01-01

    John Tinker and Mary Beth Tinker are back in a classroom in their hometown, once again wearing black armbands and drawing attention to a war. Now in their 50s, the siblings are living symbols of constitutional rights for secondary school students. In 1965, they and a handful of others were suspended for wearing black armbands to their public…

  11. Living Jointness

    DTIC Science & Technology

    1994-01-01

    reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of...COVERED 00-00-1993 to 00-00-1994 4. TITLE AND SUBTITLE Living Jointness 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR...and the peacetime activities of all services other than participation in joint exercises. It challenges the existing joint command structure because

  12. Indole production provides limited benefit to Escherichia coli during co-culture with Enterococcus faecalis.

    PubMed

    Pringle, Shelly L; Palmer, Kelli L; McLean, Robert J C

    2017-01-01

    Escherichia coli lives in the gastrointestinal tract and elsewhere, where it coexists within a mixed population. Indole production enables E. coli to grow with other gram-negative bacteria as indole inhibits N-acyl-homoserine lactone (AHL) quorum regulation. We investigated whether E. coli indole production enhanced competition with gram-positive Enterococcus faecalis, wherein quorum signaling is mediated by small peptides. During planktonic co-culture with E. faecalis, the fitness and population density of E. coli tnaA mutants (unable to produce indole) equaled or surpassed that of E. coli wt. During biofilm growth, the fitness of both populations of E. coli stabilized around 100 %, whereas the fitness of E. faecalis declined over time to 85-90 %, suggesting that biofilm and planktonic populations have different competition strategies. Media supplementation with indole removed the competitive advantage of E. coli tnaA in planktonic populations but enhanced it in biofilm populations. E. coli wt and tnaA showed similar growth in Luria-Bertani (LB) broth. However, E. coli growth was inhibited in the presence of filter-sterilized spent LB from E. faecalis, with inhibition being enhanced by indole. Similarly, there was also an inhibition of E. faecalis growth by proteinaceous components (likely bacteriocins) from spent culture media from both E. coli strains. We conclude that E. coli indole production is not a universal competition strategy, but rather works against gram-negative, AHL-producing bacteria.

  13. Triglyceride kinetics in fasted and fed E. coli septic rats

    SciTech Connect

    Lanza-Jacoby, S.; Tabares, A. )

    1990-02-26

    The mechanism for the development of hypertriglyceridemia during gram-negative sepsis was studies by examining the liver production and clearance of very-low-density lipoprotein (VLDL) triglyceride (TG). To assess the liver output and peripheral clearance the kinetics of VLDL-TG were determined by a constant intravenous infusion of (2-{sup 3}H) glycerol-labeled VLDL in fasted control, fasted E. coli-treated, fed control, and fed E.coli-treated rats. Lewis inbred rats, 275-300 g, were made septic with 8 {times} 10{sup 7} live E.coli colonies per 100 g body weight. Twenty-four hours following E.coli injection serum TG of fasted E.coli-treated rats was elevated by 170% which was attributed to a 67% decrease in the clearance rate of VLDL-TG in fasted E.coli-treated rats compared with their fasted controls. The secretion of VLDL-TG declined by 31% in the livers of the fasted E.coli-treated rats which was accompanied by a 2-fold increase in the composition of liver TG. In a second series of experiments control and E.coli-treated rats were fed intragastrically (IG) a balanced solution containing glucose plus fat as the sources of nonprotein calories. Serum TG were 26% lower in the fed E.coli-treated rats because the clearance rate increased by 86%. The secretion of TG in the fed septic rats increased by 40% but this difference was not significant. In the septic rat the ability to clear triglycerides from the plasma depends upon the nutritional state.

  14. Measuring the Viscosity of the Escherichia coli Plasma Membrane Using Molecular Rotors.

    PubMed

    Mika, Jacek T; Thompson, Alexander J; Dent, Michael R; Brooks, Nicholas J; Michiels, Jan; Hofkens, Johan; Kuimova, Marina K

    2016-10-04

    The viscosity is a highly important parameter within the cell membrane, affecting the diffusion of small molecules and, hence, controlling the rates of intracellular reactions. There is significant interest in the direct, quantitative assessment of membrane viscosity. Here we report the use of fluorescence lifetime imaging microscopy of the molecular rotor BODIPY C10 in the membranes of live Escherichia coli bacteria to permit direct quantification of the viscosity. Using this approach, we investigated the viscosity in live E. coli cells, spheroplasts, and liposomes made from E. coli membrane extracts. For live cells and spheroplasts, the viscosity was measured at both room temperature (23°C) and the E. coli growth temperature (37°C), while the membrane extract liposomes were studied over a range of measurement temperatures (5-40°C). At 37°C, we recorded a membrane viscosity in live E. coli cells of 950 cP, which is considerably higher than that previously observed in other live cell membranes (e.g., eukaryotic cells, membranes of Bacillus vegetative cells). Interestingly, this indicates that E. coli cells exhibit a high degree of lipid ordering within their liquid-phase plasma membranes. Copyright © 2016 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  15. E. coli on the move

    NASA Astrophysics Data System (ADS)

    Calne, S.

    2012-04-01

    Lynn Grove High School in Great Yarmouth, UK has been awarded a Royal Society partnership grant. Lynn Grove pupils aged between 11 and 16 years will carry out an investigation collaborating with scientists at the John Innes Centre in Norwich, UK to investigate the distribution of E.coli and other coliform bacteria within a school. The information will be used as an evidence base to educate pupils about the transmission of microbes and about methods of control. Through this work pupils will gain an appreciation of the diversity of microbial biochemistry and the chemistry behind chromogenic detection methodologies for specific bacterial enzymes. Inferences from the use of diagnostic selective media will be confirmed by carrying out DNA isolation and PCR to identify the genes responsible for the biochemical reactions. PCR will also be used to identify species of coliforms by reference to genomic sequence databases. These techniques will allow pupils to look into an unseen world in a way which has direct relevance to their everyday lives. Furthermore this partnership study will demonstrate to pupils that solving scientific questions requires the integration of a variety of scientific disciplines. The project will run from January 2012 until June 2012. We will present our preliminary results from the investigation and outline our future plans.

  16. Nitric oxide donor-mediated killing of bioluminescent Escherichia coli.

    PubMed Central

    Virta, M; Karp, M; Vuorinen, P

    1994-01-01

    The antimicrobial activities of two nitric oxide-releasing compounds against Escherichia coli were investigated by using recombinant E. coli cloned with a luciferase gene from Pyrophorus plagiophthalamus. Since luciferase uses intracellular ATP to generate visible light which can be measured from living cells in real time, we wanted to compare the extent to which cell viability parallels light emission. Results from luminescence measurements and CFU counts were in good agreement, and the decrease in light emission was shown to provide a rapid and more sensitive indication of cytotoxicity. PMID:7695261

  17. In vivo Bactericidal Activity of Mouse Complement Against Esch. coli

    PubMed Central

    Medhurst, Fiona A.; Glynn, A. A.

    1970-01-01

    Live Escherichia coli of complement sensitive and resistant strains were labelled with 14C and injected i.v. into normal mice and into a co-isogenic strain deficient in C′5. The fate of the bacteria was followed by determining total and viable counts in blood samples taken at intervals over a 30 min. period and in homogenates of the liver, spleen, lungs and kidneys taken at the end of the experiment. The results show that sensitive bacteria can be killed by mouse complement within the circulation and suggest that complement may also play a part in the intracellular killing of Esch. coli in some organs. PMID:4923650

  18. Inducible repair of oxidative DNA damage in Escherichia coli.

    PubMed

    Demple, B; Halbrook, J

    Hydrogen peroxide is lethal to many cell types, including the bacterium Escherichia coli. Peroxides yield transient radical species that can damage DNA and cause mutations. Such partially reduced oxygen species are occasionally released during cellular respiration and are generated by lethal and mutagenic ionizing radiation. Because cells live in an environment where the threat of oxidative DNA damage is continual, cellular mechanisms may have evolved to avoid and repair this damage. Enzymes are known which evidently perform these functions. We report here that resistance to hydrogen peroxide toxicity can be induced in E. coli, that this novel induction is specific and occurs, in part, at the level of DNA repair.

  19. Enterotoxigenic Escherichia coli

    PubMed Central

    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

  20. ISS Live!

    NASA Technical Reports Server (NTRS)

    Price, Jennifer; Harris, Philip; Hochstetler, Bruce; Guerra, Mark; Mendez, Israel; Healy, Matthew; Khan, Ahmed

    2013-01-01

    International Space Station Live! (ISSLive!) is a Web application that uses a proprietary commercial technology called Lightstreamer to push data across the Internet using the standard http port (port 80). ISSLive! uses the push technology to display real-time telemetry and mission timeline data from the space station in any common Web browser or Internet- enabled mobile device. ISSLive! is designed to fill a unique niche in the education and outreach areas by providing access to real-time space station data without a physical presence in the mission control center. The technology conforms to Internet standards, supports the throughput needed for real-time space station data, and is flexible enough to work on a large number of Internet-enabled devices. ISSLive! consists of two custom components: (1) a series of data adapters that resides server-side in the mission control center at Johnson Space Center, and (2) a set of public html that renders the data pushed from the data adapters. A third component, the Lightstreamer server, is commercially available from a third party and acts as an intermediary between custom components (1) and (2). Lightstreamer also provides proprietary software libraries that are required to use the custom components. At the time of this reporting, this is the first usage of Web-based, push streaming technology in the aerospace industry.

  1. Analyses of intestinal commensal Escherichia coli strains from wild boars suggest adaptation to conventional pig production conditions.

    PubMed

    Römer, Antje; Wieler, Lothar H; Schierack, Peter

    2012-12-28

    To test the hypothesis that Escherichia coli populations have adapted to conventional pig production practices, we comparatively tested intestinal commensal E. coli from wild boars versus isolates from domestic pigs by analyzing virulence-associated factors, adhesion, and metabolic activities. Virulence-associated genes typical for intestinal pathogenic E. coli (inVAGs) were sporadically detected among E. coli from wild boars except the adhesion-related gene paa and the enterotoxin-encoding gene astA. In contrast, several VAGs typical for extraintestinal pathogenic E. coli (exVAGs) were common in E. coli from wild boars. The exVAG chuA occurred more often in E. coli from wild boars compared to E. coli from domestic pigs. 23.5% of E. coli from wild boars belonged to EcoR group B2 which is higher than observed for E. coli from clinically healthy domestic pigs. Furthermore, E. coli from wild boars were more efficient in fermentation of carbohydrate sources (dulcitol, inositol, d-sucrose, d-tagatose), and adhered better to the intestinal porcine epithelial cell line IPEC-J2. In conclusion, our findings point towards an adaptation of porcine intestinal E. coli to a specific intestinal milieu caused by different animal living conditions.

  2. Investigation of E. coli Enterotoxins.

    DTIC Science & Technology

    1976-08-01

    It has been determined that representative culture filtrates from two different strains (H197 and 74-114) of enterotoxigenic E . coli contain at least...for E . coli entorotoxin (soluble) and that trypsin-activated insol ECT is more antigenic than unactivated insol ECT. In contrast, it was determined...that cholera (ga) toxoid, with or without adjuvant, stimulates antitoxin capable of neutralizing both cholera and E . coli enterotoxins. It has been

  3. Living Nanomachines

    NASA Astrophysics Data System (ADS)

    Carlier, M.-F.; Helfer, E.; Wade, R.; Haraux, F.

    The living cell is a kind of factory on the microscopic scale, in which an assembly of modular machines carries out, in a spatially and temporally coordinated way, a whole range of activities internal to the cell, including the synthesis of substances essential to its survival, intracellular traffic, waste disposal, and cell division, but also activities related to intercellular communication and exchanges with the outside world, i.e., the ability of the cell to change shape, to move within a tissue, or to organise its own defence against attack by pathogens, injury, and so on. These nanomachines are made up of macromolecular assemblies with varying degrees of complexity, forged by evolution, within which work is done as a result of changes in interactions between proteins, or between proteins and nucleic acids, or between proteins and membrane components. All these cell components measure a few nanometers across, so the mechanical activity of these nanomachines all happens on the nanometric scale. The directional nature of the work carried out by biological nanomachines is associated with a dissipation of energy. As examples of protein assemblies, one could mention the proteasome, which is responsible for the degradation of proteins, and linear molecular motors such as actomyosin, responsible for muscle contraction, the dynein-microtubule system, responsible for flagellar motility, and the kinesin-microtubule system, responsible for transport of vesicles, which transform chemical energy into motion. Nucleic acid-protein assemblies include the ribosome, responsible for synthesising proteins, polymerases, helicases, elongation factors, and the machinery of DNA replication and repair; the mitotic spindle is an integrated system involving several of these activities which drive chromosome segregation. The machinery coupling membranes and proteins includes systems involved in the energy metabolism, such as the ATP synthase rotary motor, signalling cascades, endocytosis

  4. Genetic Attributes of E. coli Isolates from Chlorinated Drinking Water

    PubMed Central

    Blyton, Michaela D. J.; Gordon, David M.

    2017-01-01

    Escherichia coli, is intimately associated with both human health and water sanitation. E. coli isolates from water can either be (i) host associated commensals, indicating recent faecal contamination; (ii) diarrheal pathogens or (iii) extra-intestinal pathogens that pose a direct health risk; or (iv) free-living. In this study we genetically characterised 28 E. coli isolates obtained from treated drinking water in south eastern Australia to ascertain their likely source. We used full genome sequencing to assign the isolates to their phylogenetic group and multi-locus sequence type. The isolates were also screened in silico for several virulence genes and genes involved in acquired antibiotic resistance. The genetic characteristics of the isolates indicated that four isolates were likely human pathogens. However, these isolates were not detected in sufficient numbers to present a health risk to the public. An additional isolate was a human associated strain. Nine isolates were water associated free-living strains that were unlikely to pose a health risk. Only 14% of the isolates belonged to the host associated phylogenetic group (B2) and only a single isolate had any antibiotic resistance genes. This suggests that the primary source of the drinking water E. coli isolates may not have been recent human faecal contamination. PMID:28107364

  5. Genetic Attributes of E. coli Isolates from Chlorinated Drinking Water.

    PubMed

    Blyton, Michaela D J; Gordon, David M

    2017-01-01

    Escherichia coli, is intimately associated with both human health and water sanitation. E. coli isolates from water can either be (i) host associated commensals, indicating recent faecal contamination; (ii) diarrheal pathogens or (iii) extra-intestinal pathogens that pose a direct health risk; or (iv) free-living. In this study we genetically characterised 28 E. coli isolates obtained from treated drinking water in south eastern Australia to ascertain their likely source. We used full genome sequencing to assign the isolates to their phylogenetic group and multi-locus sequence type. The isolates were also screened in silico for several virulence genes and genes involved in acquired antibiotic resistance. The genetic characteristics of the isolates indicated that four isolates were likely human pathogens. However, these isolates were not detected in sufficient numbers to present a health risk to the public. An additional isolate was a human associated strain. Nine isolates were water associated free-living strains that were unlikely to pose a health risk. Only 14% of the isolates belonged to the host associated phylogenetic group (B2) and only a single isolate had any antibiotic resistance genes. This suggests that the primary source of the drinking water E. coli isolates may not have been recent human faecal contamination.

  6. ANIMAL ENTEROTOXIGENIC ESCHERICHIA COLI

    PubMed Central

    Dubreuil, J. Daniel; Isaacson, Richard E.; Schifferli, Dieter M.

    2016-01-01

    Enterotoxigenic Escherichia coli (ETEC) is the most common cause of E. coli diarrhea in farm animals. ETEC are characterized by the ability to produce two types of virulence factors; adhesins that promote binding to specific enterocyte receptors for intestinal colonization and enterotoxins responsible for fluid secretion. The best-characterized adhesins are expressed in the context of fimbriae, such as the F4 (also designated K88), F5 (K99), F6 (987P), F17 and F18 fimbriae. Once established in the animal small intestine, ETEC produces enterotoxin(s) that lead to diarrhea. The enterotoxins belong to two major classes; heat-labile toxin that consist of one active and five binding subunits (LT), and heat-stable toxins that are small polypeptides (STa, STb, and EAST1). This chapter describes the disease and pathogenesis of animal ETEC, the corresponding virulence genes and protein products of these bacteria, their regulation and targets in animal hosts, as well as mechanisms of action. Furthermore, vaccines, inhibitors, probiotics and the identification of potential new targets identified by genomics are presented in the context of animal ETEC. PMID:27735786

  7. Investigation of E. coli Enterotoxins.

    DTIC Science & Technology

    In the course of investigating E . coli enterotoxins, it was discovered that trypsin treatment of partially purified enterotoxin from strain H197 (078...loops) did exhibit elevated PF titers compared with uninoculated controls. These findings are consistent with the hypothesis that E . coli enterotoxins

  8. Gravity sensing by Escherichia coli.

    PubMed

    Shimoshige, Hirokazu; Kobayashi, Hideki; Shimamura, Shigeru; Usami, Ron

    2010-01-01

    We investigated the growth and protein profile of Escherichia coli under various gravity strengths to determine the effects of hypergravity on biochemical reactions. E. coli grows at less than 7,500 g without inhibition. Hypergravity induced OmpW and Antigen 43. Changes in gravity strength altered the expression levels of these proteins. This suggests that hypergravity regulates gene expression in bacteria.

  9. Programming controlled adhesion of E. coli to target surfaces, cells, and tumors with synthetic adhesins.

    PubMed

    Piñero-Lambea, Carlos; Bodelón, Gustavo; Fernández-Periáñez, Rodrigo; Cuesta, Angel M; Álvarez-Vallina, Luis; Fernández, Luis Ángel

    2015-04-17

    In this work we report synthetic adhesins (SAs) enabling the rational design of the adhesion properties of E. coli. SAs have a modular structure comprising a stable β-domain for outer membrane anchoring and surface-exposed immunoglobulin domains with high affinity and specificity that can be selected from large repertoires. SAs are constitutively and stably expressed in an E. coli strain lacking a conserved set of natural adhesins, directing a robust, fast, and specific adhesion of bacteria to target antigenic surfaces and cells. We demonstrate the functionality of SAs in vivo, showing that, compared to wild type E. coli, lower doses of engineered E. coli are sufficient to colonize solid tumors expressing an antigen recognized by the SA. In addition, lower levels of engineered bacteria were found in non-target tissues. Therefore, SAs provide stable and specific adhesion capabilities to E. coli against target surfaces of interest for diverse applications using live bacteria.

  10. Programming Controlled Adhesion of E. coli to Target Surfaces, Cells, and Tumors with Synthetic Adhesins

    PubMed Central

    2014-01-01

    In this work we report synthetic adhesins (SAs) enabling the rational design of the adhesion properties of E. coli. SAs have a modular structure comprising a stable β-domain for outer membrane anchoring and surface-exposed immunoglobulin domains with high affinity and specificity that can be selected from large repertoires. SAs are constitutively and stably expressed in an E. coli strain lacking a conserved set of natural adhesins, directing a robust, fast, and specific adhesion of bacteria to target antigenic surfaces and cells. We demonstrate the functionality of SAs in vivo, showing that, compared to wild type E. coli, lower doses of engineered E. coli are sufficient to colonize solid tumors expressing an antigen recognized by the SA. In addition, lower levels of engineered bacteria were found in non-target tissues. Therefore, SAs provide stable and specific adhesion capabilities to E. coli against target surfaces of interest for diverse applications using live bacteria. PMID:25045780

  11. [Living better or living longer].

    PubMed

    Sauvy, A

    1987-01-01

    It has been just 2 centuries since France began to struggle seriously against mortality and excess fertility. Life expectancy, which for millenia had been under 30 years at birth, began to increase because of the discovery of effective treatments, improved production and standards of living, and access of large numbers of persons to health care. France, in the 2nd half of the 18th century, became the first country in which fertility regulation was achieved on a wide scale. The failure of England, a country of similar culture, to follow suit until a century later remains unexplained. After World War II, simple and fairly inexpensive means of mortality control, such as vaccines and water purifiers, became widely distributed throughout the developing world. These countries, which traditionally had mortality rates of 35 or 40/1000 and fertility of 40-45/1000, experienced rapid declines in mortality rates while their fertility remained constant or even increased. Because antinatal techniques diffused so much more slowly, the equilibrium of births and deaths was disturbed as rates of increase of 2 or 3% per year became common. Although the inhabitants of poor countries were not concerned, perhaps through ignorance of what was occurring, the rich countries were alarmed by the increase. Their principal objective became to spread contraception in the poor countries. The available methods at the time, however, were none too reliable. When oral contraceptive pills became available, fertility dropped to very low levels in Europe but such factors as cost and illiteracy discouraged use in many underdeveloped countries. Fertility declined in a few insular states such as Hong Kong, Taiwan, and Singapore even before the appearance of pills. Life expectancies in developing countries except a few in Africa have increased since World War II and are now higher than in Europe at the turn of the century. "Health for all by the year 2000" is an astonishing slogan for a serious

  12. Escherichia coli adherence to HEp-2 cells with prefixed cells.

    PubMed Central

    Zepeda-Lopez, H M; Gonzalez-Lugo, G M

    1995-01-01

    We describe a new method which uses cold absolute methanol-prefixed cells for adherence of enteropathogenic Escherichia coli to HEp-2 cells. We found that a method using bacteria grown in Penassay broth to 10(6) to 10(7) CFU/ml and incubated with prefixed cells for 3 h at 37 degrees C, showed 100% sensitivity and specificity against a method using live cells. PMID:7615770

  13. Electric field induced bacterial flocculation of Enteroaggregative Escherichia coli 042

    SciTech Connect

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

    2011-01-01

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

  14. Extraintestinal pathogenic Escherichia coli: "the other bad E coli".

    PubMed

    Johnson, James R; Russo, Thomas A

    2002-03-01

    Extraintestinal pathogenic Escherichia coli (ExPEC), the specialized strains of E coli that cause most extraintestinal E coli infections, represent a major but little-appreciated health threat. Although the reasons for their evolution remain mysterious, by virtue of their numerous virulence traits ExPEC clearly possess a unique ability to cause disease outside the host intestinal tract. Broader appreciation of the existence and importance of ExPEC and better understandings of their distinctive virulence mechanisms, reservoirs, and transmission pathways may lead to effective preventive interventions against the morbid and costly infections ExPEC cause.

  15. From Living Carbocationic to Living Radical Polymerization.

    DTIC Science & Technology

    1994-06-30

    C 1 -OFFICE OF NAVAL RESEARCH CONTRACT N00014-94-1-0101 R&T Code 31321075 Technical Report No. 18 FROM " LIVING " CARBOCATIONIC TO " LIVING " RADICAL...NUMBERS "From Living " Carbocationic to " Living " ’jical Polymerization N00014-94-1-01I01 6. AUTHOR(S) Krzysztof Matyjaszewski 7. PERFORMING ORGANIZATION NAME...1994) 1Za. DISTRIBUTION I AVAILABILITY STATEMENT 12b. DISTRIBUTION CODE 13. ABSTRACT (Maximum 200 words) " Living " carbocationic polymerization is

  16. Nucleotide excision repair in Escherichia coli.

    PubMed Central

    Van Houten, B

    1990-01-01

    One of the best-studied DNA repair pathways is nucleotide excision repair, a process consisting of DNA damage recognition, incision, excision, repair resynthesis, and DNA ligation. Escherichia coli has served as a model organism for the study of this process. Recently, many of the proteins that mediate E. coli nucleotide excision have been purified to homogeneity; this had led to a molecular description of this repair pathway. One of the key repair enzymes of this pathway is the UvrABC nuclease complex. The individual subunits of this enzyme cooperate in a complex series of partial reactions to bind to and incise the DNA near a damaged nucleotide. The UvrABC complex displays a remarkable substrate diversity. Defining the structural features of DNA lesions that provide the specificity for damage recognition by the UvrABC complex is of great importance, since it represents a unique form of protein-DNA interaction. Using a number of in vitro assays, researchers have been able to elucidate the action mechanism of the UvrABC nuclease complex. Current research is devoted to understanding how these complex events are mediated within the living cell. PMID:2181258

  17. Thiophene metabolism by E. coli

    SciTech Connect

    Clark, D.P.

    1990-01-01

    The objective of this project is to investigate the mechanism of degradation of sulfur containing heterocyclic molecules by mutants of Escherichia coli K-12. We previously isolated multiple mutants of E. coli which were selected for improved oxidation of furan and thiophene derivatives. We have focused on the thdA mutation in our subsequent research as it appears to be of central importance in thiophene oxidation. We hope that analysis of the thd gene of E. coli will lead to improvement of our thiophene metabolizing bacterial strains.

  18. Meta-Analysis of Transcriptional Responses to Mastitis-Causing Escherichia coli.

    PubMed

    Younis, Sidra; Javed, Qamar; Blumenberg, Miroslav

    2016-01-01

    Bovine mastitis is a widespread disease in dairy cows, and is often caused by bacterial mammary gland infection. Mastitis causes reduced milk production and leads to excessive use of antibiotics. We present meta-analysis of transcriptional profiles of bovine mastitis from 10 studies and 307 microarrays, allowing identification of much larger sets of affected genes than any individual study. Combining multiple studies provides insight into the molecular effects of Escherichia coli infection in vivo and uncovers differences between the consequences of E. coli vs. Staphylococcus aureus infection of primary mammary epithelial cells (PMECs). In udders, live E. coli elicits inflammatory and immune defenses through numerous cytokines and chemokines. Importantly, E. coli infection causes downregulation of genes encoding lipid biosynthesis enzymes that are involved in milk production. Additionally, host metabolism is generally suppressed. Finally, defensins and bacteria-recognition genes are upregulated, while the expression of the extracellular matrix protein transcripts is silenced. In PMECs, heat-inactivated E. coli elicits expression of ribosomal, cytoskeletal and angiogenic signaling genes, and causes suppression of the cell cycle and energy production genes. We hypothesize that heat-inactivated E. coli may have prophylactic effects against mastitis. Heat-inactivated S. aureus promotes stronger inflammatory and immune defenses than E. coli. Lipopolysaccharide by itself induces MHC antigen presentation components, an effect not seen in response to E. coli bacteria. These results provide the basis for strategies to prevent and treat mastitis and may lead to the reduction in the use of antibiotics.

  19. Meta-Analysis of Transcriptional Responses to Mastitis-Causing Escherichia coli

    PubMed Central

    Younis, Sidra; Javed, Qamar; Blumenberg, Miroslav

    2016-01-01

    Bovine mastitis is a widespread disease in dairy cows, and is often caused by bacterial mammary gland infection. Mastitis causes reduced milk production and leads to excessive use of antibiotics. We present meta-analysis of transcriptional profiles of bovine mastitis from 10 studies and 307 microarrays, allowing identification of much larger sets of affected genes than any individual study. Combining multiple studies provides insight into the molecular effects of Escherichia coli infection in vivo and uncovers differences between the consequences of E. coli vs. Staphylococcus aureus infection of primary mammary epithelial cells (PMECs). In udders, live E. coli elicits inflammatory and immune defenses through numerous cytokines and chemokines. Importantly, E. coli infection causes downregulation of genes encoding lipid biosynthesis enzymes that are involved in milk production. Additionally, host metabolism is generally suppressed. Finally, defensins and bacteria-recognition genes are upregulated, while the expression of the extracellular matrix protein transcripts is silenced. In PMECs, heat-inactivated E. coli elicits expression of ribosomal, cytoskeletal and angiogenic signaling genes, and causes suppression of the cell cycle and energy production genes. We hypothesize that heat-inactivated E. coli may have prophylactic effects against mastitis. Heat-inactivated S. aureus promotes stronger inflammatory and immune defenses than E. coli. Lipopolysaccharide by itself induces MHC antigen presentation components, an effect not seen in response to E. coli bacteria. These results provide the basis for strategies to prevent and treat mastitis and may lead to the reduction in the use of antibiotics. PMID:26933871

  20. Elevated Risk of Carrying Gentamicin-Resistant Escherichia coli among U.S. Poultry Workers

    PubMed Central

    Price, Lance B.; Graham, Jay P.; Lackey, Leila G.; Roess, Amira; Vailes, Rocio; Silbergeld, Ellen

    2007-01-01

    Background Antimicrobial use in food-animal production is an issue of growing concern. The application of antimicrobials for therapy, prophylaxis, and growth promotion in broiler chicken production has been associated with the emergence and dissemination of antimicrobial-resistant enteric bacteria. Although human exposure to antimicrobial-resistant bacteria through food has been examined extensively, little attention has been paid to occupational and environmental pathways of exposure. Objective Our objective was to measure the relative risk for colonization with antimicrobial-resistant Escherichia coli among poultry workers compared with community referents. Methods We collected stool samples and health surveys from 16 poultry workers and 33 community referents in the Delmarva region of Maryland and Virginia. E. coli was cultured from stool samples, and susceptibility to ampicillin, ciprofloxacin, ceftriaxone, gentamicin, nitrofurantoin, and tetracycline was determined for each E. coli isolate. We estimated the relative risk for carrying antimicrobial-resistant E. coli among poultry workers compared with community referents. Results Poultry workers had 32 times the odds of carrying gentamicin-resistant E. coli compared with community referents. The poultry workers were also at significantly increased risk of carrying multidrug-resistant E. coli. Conclusions Occupational exposure to antimicrobial-resistant E. coli from live-animal contact in the broiler chicken industry may be an important route of entry for antimicrobial-resistant E. coli into the community. PMID:18087592

  1. Persistence of Indigenous Escherichia coli in Raw Bovine Manure-Amended Soil.

    PubMed

    Çekiç, Samantha K; De, Jaysankar; Jubair, Mohammad; Schneider, Keith R

    2017-09-01

    The Food Safety Modernization Act attempts to reduce produce-related foodborne illness by using preventive rather than reactive measures. The goal of this research was to determine the persistence of manure-borne generic Escherichia coli under laboratory and field conditions. The population density of naturally occurring E. coli was ∼7.2 and 5.4 log CFU/10 g in pre- and postscreened manures, respectively. Postscreened (i.e. after the liquid manure has passed through a screen) manure was applied at light, medium, and heavy rates to fields in Live Oak and Citra, FL, during the fall and summer. Laboratory microcosms of the manure-amended soils (comparable to the field's heavy application rate of manure) from both locations were maintained at 20 and 30°C. Persistence of E. coli, moisture content, and pH were monitored until E. coli became unrecoverable. The longest E. coli persistence seen in field trails was during the summer and fall trials from Citra (heavy application) that terminated on day 112 and day 280, respectively. The rate of E. coli decay ranged from 0.02 to 0.04 log CFU per day across all manure application rates, seasons, and locations. In the microcosm studies, the E. coli became extinct on day 210 in the 30°C, whereas they became unrecoverable on day 420 in the 20°C microcosms. The relatively prolonged persistence of E. coli in the microcosms suggests that survival under laboratory conditions does not mimic real-world survival rates and may not be adequate for predicting E. coli persistence in the field. The persistence data also suggest that the risk from E. coli associated with new contamination events, such as wild life intrusion, runoff, or other vectors, may be greater than the risk associated with the long-term survival of manure-borne E. coli, although more work is needed to confirm this hypothesis.

  2. [Virulence mechanisms of enteropathogenic Escherichia coli].

    PubMed

    Farfán-García, Ana Elvira; Ariza-Rojas, Sandra Catherine; Vargas-Cárdenas, Fabiola Andrea; Vargas-Remolina, Lizeth Viviana

    2016-08-01

    Acute diarrheal disease (ADD) is a global public health problem, especially in developing countries and is one of the causes of mortality in children under five. ADD etiologic agents include viruses, bacteria and parasites in that order. Escherichia coli bacteria it is classified as a major diarrheagenic agent and transmitted by consuming contaminated water or undercooked foods. This review compiled updates on information virulence factors and pathogenic mechanisms involved in adhesion and colonization of seven pathotypes of E. coli called enteropathogenic E. coli (EPEC), enterotoxigenic E. coli (ETEC), enteroinvasive E. coli (EIEC), shigatoxigenic E. coli (STEC), enteroaggregative E. coli (EAEC) and diffusely-adherent E. coli (DAEC). A final pathotype, adherent-invasive E. coli (AIEC) associated with Crohn's disease was also reviewed. The diarrheagenic pathotypes of E. coli affect different population groups and knowledge of the molecular mechanisms involved in the interaction with the human is important to guide research towards the development of vaccines and new tools for diagnosis and control.

  3. Importance of Escherichia coli in young beef calves from northwestern Quebec.

    PubMed Central

    Ganaba, R; Bigras-Poulin, M; Fairbrother, J M; Bélanger, D

    1995-01-01

    The objectives of this study were: (i) to investigate the prevalence of Escherichia coli producing F5 (K99), F41, or F165 fimbriae and STa enterotoxin; (ii) to determine serum antibody levels against these fimbriae; (iii) and to examine the association between bacteriological and serological results and the presence of diarrhea, in beef calves from northwestern Quebec. A total of 373 live three to four week old calves and 27 dead calves were sampled between January and March 1991. No isolates positive for F5 were detected in live calves, and only one E. coli producing STa and F41 was isolated. Escherichia coli producing F41-like surface antigens or F165 fimbriae were isolated from 17.43% and 5.63% of live calves, respectively. Antibodies against F5, F41 and F165 were low. Escherichia coli isolates positive for F41-like surface antigen were most often observed in calves born between January and March. No association was found between bacteriological and serological findings, nor between these findings and diarrhea. Calves born from dams vaccinated against E. coli had higher median antibody levels than those born from unvaccinated dams. No E. coli positive for F5 or F41 fimbriae were isolated from dead calves. Escherichia coli with F41-like surface antigen or F165 were found in 55.56% and 11.11% of ileal samples; 4% and 16% of cecal samples, and 0% and 7.4% of colon samples, respectively. Escherichia coli positive for F41-like surface antigen were detected significantly more frequently in the ileum (chi (2)2df = 31.01, p < 0.001). PMID:7704838

  4. Magnetically-Actuated Escherichia coli System for Micro Lithography

    NASA Astrophysics Data System (ADS)

    Lauback, S.; Brown, E.; Pérez-Guzman, L.; Peace, C.; Pierce, C.; Lower, B. H.; Lower, S. K.; Sooryakumar, R.

    2015-03-01

    Technologies that control matter at the nano- and micro-scale are crucial for developing new engineered materials and devices. While the more traditional approaches for such manipulations often depend on lithographic fabrication, they can be expanded upon by taking advantage of the biological systems within a living cell which also operate on the nano- and micro- scale. In this study, a system is being developed to functionalize a targeted location on the surface of a chip with the protein AmCyan from transformed Escherichia coli cells. Using established methods in molecular biology where a plasmid with the amcyan gene sequence is inserted into the cell, E. coli are engineered to express the AmCyan protein on their outer surface. In order to transport the cells to the targeted location, the transformed E. coli are labeled with superparamagnetic micro-beads which exert directed forces on the cells in an external field. Preliminary results of the protein expression on E. coli, the transport of the cell through weak magnetic fields to targeted locations and the potential to transfer protein from the cell to the chip surface will be presented.

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

    PubMed Central

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

    2012-01-01

    Parrots in captivity are frequently affected by Escherichia coli (E. coli) infections. The objective of this study was to collect information on the carrier state for E. coli pathotypes in asymptomatic free-ranging parrots. Cloacal swabs were collected from nestlings of Hyacinth, Lear's macaws and Blue-fronted Amazon parrots and tested by polymerase chain reaction (PCR) for virulence factors commonly found in enteropathogenic, avian pathogenic, and uropathogenic E. coli strains. In total, 44 samples were cultured and E. coli isolates were yielded, from which DNA was extracted and processed by PCR. Genes commonly found in APEC isolates from Blue-fronted Amazon parrots and Hyacinth macaws were expressed in 14 of these 44 samples. One atypical EPEC isolate was obtained from a sample from Lear's macaw. The most commonly found gene was the increased serum survival (iss) gene. This is the first report, that describes such pathotypes in asymptomatic free-living parrots. The findings of this study suggest the presence of a stable host/parasite relationship at the time of the sampling brings a new understanding to the role that E. coli plays in captive and wild parrots. Such information can be used to improve husbandry protocols as well as help conservation efforts of free-living populations. PMID:23738135

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

    PubMed

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

    2012-01-01

    Parrots in captivity are frequently affected by Escherichia coli (E. coli) infections. The objective of this study was to collect information on the carrier state for E. coli pathotypes in asymptomatic free-ranging parrots. Cloacal swabs were collected from nestlings of Hyacinth, Lear's macaws and Blue-fronted Amazon parrots and tested by polymerase chain reaction (PCR) for virulence factors commonly found in enteropathogenic, avian pathogenic, and uropathogenic E. coli strains. In total, 44 samples were cultured and E. coli isolates were yielded, from which DNA was extracted and processed by PCR. Genes commonly found in APEC isolates from Blue-fronted Amazon parrots and Hyacinth macaws were expressed in 14 of these 44 samples. One atypical EPEC isolate was obtained from a sample from Lear's macaw. The most commonly found gene was the increased serum survival (iss) gene. This is the first report, that describes such pathotypes in asymptomatic free-living parrots. The findings of this study suggest the presence of a stable host/parasite relationship at the time of the sampling brings a new understanding to the role that E. coli plays in captive and wild parrots. Such information can be used to improve husbandry protocols as well as help conservation efforts of free-living populations.

  7. DNA fingerprinting approaches to trace Escherichia coli sharing between dogs and owners.

    PubMed

    Naziri, Z; Derakhshandeh, A; Firouzi, R; Motamedifar, M; Shojaee Tabrizi, A

    2016-02-01

    To determine the prevalence of cross-species sharing of Escherichia coli between healthy dogs and humans living in the same household. Two faecal E. coli isolates from 25 healthy dog-owner pairs and 16 healthy control humans were tested using three fingerprinting methods. The prevalence of within-household sharing of E. coli was 4, 8 and 8% using pulsed-field gel electrophoresis, randomly amplified polymorphic DNA and enterobacterial repetitive intergenic consensus-PCR analyses respectively. Within-household bacterial sharing was more prevalent than across-household sharing (P < 0·05). According to questionnaire analyses avoiding the dog-owner behaviours such as allowing a dog to kiss or lick the owner's face, sharing people food with dog and feeding it raw meat may decrease the chance of cross-species E. coli sharing. Direct contact between humans and dogs and environmental reservoirs may be important routes for cross-species sharing of bacteria. Good personal hygiene and appropriate veterinary care for pets can minimize this risk. Due to the importance of canine pathogenic E. coli reservoir hypothesis, close contacts between humans and dogs raises public health concerns. Determining the rate of cross-species bacterial sharing and confirm its accuracy by different fingerprinting techniques will help to find ways for reducing the economic impact of E. coli infections. This study support claims that public health concerns regarding the cross-species sharing of E. coli are warranted but this risk is minimal. © 2015 The Society for Applied Microbiology.

  8. fur (-) mutation increases the survival time of Escherichia coli under photooxidative stress in aquatic environments.

    PubMed

    Darcan, C; Aydin, Ebru

    2012-09-01

    We investigated the survival of the wild type Escherichia coli (QC771) and fur- mutant strain (QC1732) under photooxidative stress in different water sources. The survival of fur- mutant and wild type E. coli was seen as a significant decrease in the visible light samples in the presence of methylene blue (MB). The fur-E. coli strain lived longer than the wild type E. coli strain on exposure to MB and visible light, which generates singlet oxygen, in both lake water (48-h) and pure water (16-h). It is interesting to note that the survival of both wild type and the fur- mutant strain was more protected at 24 °C than at other temperatures. The Fur protein does not have any relation to the entry of E. coli into the viable but nonculturable state (VBNC) under photooxidative stress. This is the first study which shows that fur- mutation increases the resistance of E. coli to photooxidative stress in aquatic environments, and the Fur protein does not have any relation to the entry of E. coli into the VBNC state.

  9. Population genetics of Escherichia coli in a natural population of native Australian rats.

    PubMed

    Pupo, G M; Lan, R; Reeves, P R; Baverstock, P R

    2000-12-01

    Escherichia coli, a normal inhabitant of the intestinal tract of mammals and birds, is a diverse species. Most studies on E. coli populations involve organisms from humans or human-associated animals. In this study, we undertook a survey of E. coli from native Australian mammals, predominantly Rattus tunneyi, living in a relatively pristine environment in the Bundjalung National Park. The genetic diversity was assessed and compared by multilocus enzyme electrophoresis (MLEE), sequence analysis of the mdh (malate dehydrogenase) gene and biotyping using seven sugars. Ninety-nine electrophoretic types were identified from the 242 isolates analysed by MLEE and 15 sequences from the mdh genes sequenced from 21 representative strains. The Bundjalung isolates extend the diversity represented by the E. coli reference (ECOR) set, with new MLEE alleles found in six out of 10 loci. Many of the Bundjalung isolates fell into a discrete group in MLEE. Other Bundjalung strains fell into the recognized E. coli ECOR set groups, but tended to be at the base of both the MLEE and mdh gene trees, implying that these strains are derived independently from ancestral forms of the ECOR groups and that ECOR strains represent only a subset of E. coli adapted to humans and human-associated animals. Linkage disequilibrium analysis showed that the Bundjalung population has an 'epidemic' population structure. The Bundjalung isolates were able to utilize more sugars than the ECOR strains, suggesting that diet plays a prominent role in adaptation of E. coli.

  10. The SIGNAL experiment in BIORACK: Escherichia coli in microgravity.

    PubMed

    Thévenet, D; D'Ari, R; Bouloc, P

    1996-06-27

    Microgravity affects certain physical properties of fluids, such as convection movement and surface tension. As a consequence, cells and living organisms may exhibit different behaviour in space, which may result from differences in the immediate environment of the cell or changes in the structure of the membrane in microgravity. Two experiments to examine the effects of microgravity on cell microenvironment and signal transduction through membranes were performed using a well-characterized system with different strains of the non-pathogenic Gram-negative bacterium Escherichia coli. Our results indicate that (i) microgravity appears to reduce the lag period of a non-motile culture of E. coli, and (ii) the ompC gene, regulated by the two-component system EnvZ-OmpR, is induced as well or better in microgravity than in ground controls.

  11. Administration for Community Living

    MedlinePlus

    ... Information for Current Grantees About ACL Organization Why Community Living? Authorizing Statutes Budget Mandatory Grant Allocations Strategic ... Final Rule Get ACL Updates OAA Reauthorization Why Community Living? FEATURES #InclusionWorks IL Final Rule Get ACL ...

  12. Living with VHL

    MedlinePlus

    ... Videos Contact Us Search Patients & Caregivers / Living with VHL VHL disease is a lifelong condition. However, with appropriate measures, people can effectively manage the VHL and lead full and productive lives. Early diagnosis, ...

  13. Living with VHL

    MedlinePlus

    ... News & Events Contact Us Website References Search Patients / Living with VHL VHL disease is a lifelong condition. ... regularly surveillance, appropriate treatment and emotional support, and living a healthy lifestyle are all keys to effectively ...

  14. Living with Heart Block

    MedlinePlus

    ... Share this page from the NHLBI on Twitter. Living With Heart Block First-degree heart block may ... whether you need ongoing care for your condition. Living With a Pacemaker People who have third-degree ...

  15. Living with Pulmonary Hypertension

    MedlinePlus

    ... Share this page from the NHLBI on Twitter. Living With Pulmonary Hypertension Pulmonary hypertension (PH) has no ... seek care right away. Emotional Issues and Support Living with PH may cause fear, anxiety, depression, and ...

  16. Living with Vasculitis

    MedlinePlus

    ... Share this page from the NHLBI on Twitter. Living With Vasculitis The outcome of vasculitis is hard ... effects of your medicines. Emotional Issues and Support Living with a chronic condition may cause fear, anxiety, ...

  17. Living with Sarcoidosis

    MedlinePlus

    ... page from the NHLBI on Twitter. Living With Sarcoidosis Sarcoidosis has no cure, but you can take ... Content: NEXT >> Featured Video Living With and Managing Sarcoidosis 05/18/2011 This video—presented by the ...

  18. Draft Whole-Genome Sequences of 10 Enterotoxigenic Escherichia coli Serogroup O6 Strains

    PubMed Central

    Bopp, Cheryl A.

    2015-01-01

    Enterotoxigenic Escherichia coli (ETEC) is an important cause of diarrhea in children under the age of 5 years and in adults living in developing countries, as well as in travelers to these countries. In this announcement, we release the draft whole-genome sequences of 10 ETEC serogroup O6 strains. PMID:26044422

  19. Sequential closure of the cytoplasm and then the periplasm during cell division in Escherichia coli.

    PubMed

    Skoog, Karl; Söderström, Bill; Widengren, Jerker; von Heijne, Gunnar; Daley, Daniel O

    2012-02-01

    To visualize the latter stages of cell division in live Escherichia coli, we have carried out fluorescence recovery after photobleaching (FRAP) on 121 cells expressing cytoplasmic green fluorescent protein and periplasmic mCherry. Our data show conclusively that the cytoplasm is sealed prior to the periplasm during the division event.

  20. Independent Living Course

    ERIC Educational Resources Information Center

    Tipping, Joyce

    1978-01-01

    Designed to help handicapped persons who have been living a sheltered existence develop independent living skills, this course is divided into two parts. The first part consists of a five-day apartment live-in experience, and the second concentrates on developing the learners' awareness of community resources and consumer skills. (BM)

  1. Experimental evolution of E. coli

    NASA Astrophysics Data System (ADS)

    Zhang, Mengshi

    The evolution from unicellular to multicellular behavior is an essential step in the history of life. Our aim is to investigate the emergence of collective behavior in the model organism Escherichia coli (E. coli) and its selection advantages, such as better utilization of public goods. Our preliminary results suggest that the evolution of collective behavior may be a natural response to stressed conditions. Mailing address: Room 306 Science Centre North Block, The Chinese University of Hong Kong, Shatin, N.T. Hong Kong SAR. Phone: +852-3943-6354. Fax: +852-2603-5204. E-mail: mengshi0928@gmail.com.

  2. 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.

  3. In-stream Escherichia coli Modeling

    NASA Astrophysics Data System (ADS)

    Pandey, P.; Soupir, M.

    2013-12-01

    Elevated levels of pathogenic bacteria indicators such as Escherichia coli (E. coli) in streams are a serious concern. Controlling E. coli levels in streams requires improving our existing understanding of fate and transport of E. coli at watershed scale. In-stream E. coli concentrations are potentially linked to non-point pollution sources (i.e., agricultural land). Water of a natural stream can receive E. coli by either through overland flow (via runoff from cropland) or resuspension from the streambed to the water column. Calculating in-stream total E. coli loads requires estimation of particle attached bacteria as well free floating E. coli transport. Currently water quality models commonly used for predicting E. coli levels in stream water have limited capability for predicting E. coli levels in the water column as well as in the streambed sediment. The challenges in calculating in-stream E. coli levels include difficulties in modeling the complex interactions between sediment particles and E. coli. Here we have developed a watershed scale model (integrated with Soil and Water Assessment Tool (SWAT)), which involves calculation of particle attached E. coli, to predict in-stream E. coli concentrations. The proposed model predicts E. coli levels in streambed bed sediment as well as in the water column. An extensive in-stream E. coli monitoring was carried out to verify the model predictions, and results indicate that the model performed well. The study proposed here will improve understanding on in-stream bacterial contamination, and help improving existing water quality models for predicting pathogenic bacteria levels in ambient water bodies.

  4. Investigation of ’Escherichia coli’ Enterotoxins

    DTIC Science & Technology

    1978-05-01

    E . coli diarrheal disease in man and domestic animals. Fundamentally, the design of the vaccine is based on the well- documented ability of cholera antitoxin to neutralize both cholera and heat- labile E . coli enterotoxins and on the ability of certain E . coli antigens to enhance the immune response to cholera toxoid and possibly whole-cell Cholera Vaccine, as

  5. Gentamicin in Esch. coli gastroenteritis

    PubMed Central

    Coetzee, M.; Leary, P. M.

    1971-01-01

    A study has been made of 90 Cape Town infants who presented with acute gastroenteritis and from whose stools enteropathic Escherichia coli were isolated. These children were treated with combined oral and parenteral gentamicin. On this regimen 92% of the infants recovered rapidly and only one died. PMID:4330192

  6. Exonuclease IX of Escherichia coli.

    PubMed Central

    Shafritz, K M; Sandigursky, M; Franklin, W A

    1998-01-01

    The bacteria Escherichia coli contains several exonucleases acting on both double- and single-stranded DNA and in both a 5'-->3' and 3'-->5' direction. These enzymes are involved in replicative, repair and recombination functions. We have identified a new exonuclease found in E.coli, termed exonuclease IX, that acts preferentially on single-stranded DNA as a 3'-->5' exonuclease and also functions as a 3'-phosphodiesterase on DNA containing 3'-incised apurinic/apyrimidinic (AP) sites to remove the product trans -4-hydroxy-2-pentenal 5-phosphate. The enzyme showed essentially no activity as a deoxyribophosphodiesterase acting on 5'-incised AP sites. The activity was isolated as a glutathione S-transferase fusion protein from a sequence of the E.coli genome that was 60% identical to a 260 bp region of the small fragment of the DNA polymerase I gene. The protein has a molecular weight of 28 kDa and is free of AP endonuclease and phosphatase activities. Exonuclease IX is expressed in E.coli , as demonstrated by reverse transcription-PCR, and it may function in the DNA base excision repair and other pathways. PMID:9592142

  7. Biosynthesis of a Fully Functional Cyclotide inside Living Bacterial Cells

    SciTech Connect

    Camarero, J A; Kimura, R H; Woo, Y; Cantor, J; Shekhtman, A

    2007-04-05

    The cyclotide MCoTI-II is a powerful trypsin inhibitor recently isolated from the seeds of Momordica cochinchinensis, a plant member of cucurbitaceae family. We report for the first time the in vivo biosynthesis of natively-folded MCoTI-II inside live E. coli cells. Our biomimetic approach involves the intracellular backbone cyclization of a linear cyclotide-intein fusion precursor mediated by a modified protein splicing domain. The cyclized peptide then spontaneously folds into its native conformation. The use of genetically engineered E. coli cells containing mutations in the glutathione and thioredoxin reductase genes considerably improves the production of folded MCoTI-II in vivo. Biochemical and structural characterization of the recombinant MCoTI-II confirmed its identity. Biosynthetic access to correctly-folded cyclotides allows the possibility of generating cell-based combinatorial libraries that can be screened inside living cells for their ability to modulate or inhibit cellular processes.

  8. Toxigenic Escherichia Coli and Childhood Diarrhea

    PubMed Central

    Mundell, Dave H.; Anselmo, Carl R.; Thrupp, Lauri D.; Wishnow, Rodney M.

    1976-01-01

    Stool specimens were examined from 40 children with diarrhea who were under three years of age to determine the incidence of enterotoxigenic Escherichia coli in endemic diarrhea. Heat-labile E. coli enterotoxin was assayed in the very sensitive and reproducible cultured adrenal tumor cell system. Toxigenic E. coli were isolated from only one stool specimen and in this case infection with Shigella dysenteriae was also present. None of the eight classic enteropathogenic E. coli isolates were positive in the adrenal assay. This study suggests that heat-labile enterotoxin-producing E. coli are not an important cause of endemic childhood diarrhea in Southern California. PMID:775792

  9. The endophytic lifestyle of Escherichia coli O157:H7: quantification and internal localization in roots.

    PubMed

    Wright, Kathryn M; Chapman, Sean; McGeachy, Kara; Humphris, Sonia; Campbell, Emma; Toth, Ian K; Holden, Nicola J

    2013-04-01

    The foodborne pathogen Escherichia coli O157:H7 is increasingly associated with fresh produce (fruit and vegetables). Bacterial colonization of fresh produce plants can occur to high levels on the external tissue but bacteria have also been detected within plant tissue. However, questions remain about the extent of internalization, its molecular basis, and internal location of the bacteria. We have determined the extent of internalization of E. coli O157:H7 in live spinach and lettuce plants and used high-resolution microscopy to examine colony formation in roots and pathways to internalization. E. coli O157:H7 was found within internal tissue of both produce species. Colonization occurred within the apoplast between plant cells. Furthermore, colonies were detected inside the cell wall of epidermal and cortical cells of spinach and Nicotiana benthamiana roots. Internal colonization of epidermal cells resembled that of the phytopathogen Pectobacterium atrosepticum on potato. In contrast, only sporadic cells of the laboratory strain of E. coli K-12 were found on spinach, with no internal bacteria evident. The data extend previous findings that internal colonization of plants appears to be limited to a specific group of plant-interacting bacteria, including E. coli O157:H7, and demonstrates its ability to invade the cells of living plants.

  10. Integrating artificial with natural cells to translate chemical messages that direct E. coli behaviour

    PubMed Central

    Lentini, Roberta; Santero, Silvia Perez; Chizzolini, Fabio; Cecchi, Dario; Fontana, Jason; Marchioretto, Marta; Del Bianco, Cristina; Terrell, Jessica L.; Spencer, Amy C.; Martini, Laura; Forlin, Michele; Assfalg, Michael; Serra, Mauro Dalla; Bentley, William E.; Mansy, Sheref S.

    2014-01-01

    Previous efforts to control cellular behaviour have largely relied upon various forms of genetic engineering. Once the genetic content of a living cell is modified, the behaviour of that cell typically changes as well. However, other methods of cellular control are possible. All cells sense and respond to their environment. Therefore, artificial, non-living cellular mimics could be engineered to activate or repress already existing natural sensory pathways of living cells through chemical communication. Here we describe the construction of such a system. The artificial cells expand the senses of Escherichia coli by translating a chemical message that E. coli cannot sense on its own to a molecule that activates a natural cellular response. This methodology could open new opportunities in engineering cellular behaviour without exploiting genetically modified organisms. PMID:24874202

  11. Human Meningitis-Associated Escherichia coli

    PubMed Central

    KIM, KWANG SIK

    2016-01-01

    E. coli is the most common Gram-negative bacillary organism causing meningitis and E. coli meningitis continues to be an important cause of mortality and morbidity throughout the world. Our incomplete knowledge of its pathogenesis contributes to such mortality and morbidity. Recent reports of E. coli strains producing CTX-M-type or TEM-type extended-spectrum β-lactamases create a challenge. Studies using in vitro and in vivo models of the blood-brain barrier have shown that E. coli meningitis follows a high-degree of bacteremia and invasion of the blood-brain barrier. E. coli invasion of the blood-brain barrier, the essentials step in the development of E. coli meningitis, requires specific microbial and host factors as well as microbe- and host-specific signaling molecules. Blockade of such microbial and host factors contributing to E. coli invasion of the blood-brain barrier is shown to be efficient in preventing E. coli penetration into the brain. The basis for requiring a high-degree of bacteremia for E. coli penetration of the blood-brain barrier, however, remains unclear. Continued investigation on the microbial and host factors contributing to a high-degree of bacteremia and E. coli invasion of the blood-brain barrier is likely to identify new targets for prevention and therapy of E. coli meningitis. PMID:27223820

  12. 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

  13. Characterization of a Novel Microcin That Kills Enterohemorrhagic Escherichia coli O157:H7 and O26

    PubMed Central

    Eberhart, Lauren J.; Deringer, James R.; Brayton, Kelly A.; Sawant, Ashish A.; Besser, Thomas E.

    2012-01-01

    A novel phenotype was recently identified in which specific strains of Escherichia coli inhibit competing E. coli strains via a mechanism that was designated “proximity-dependent inhibition” (PDI). PDI-expressing (PDI+) E. coli is known to inhibit susceptible (PDI−) E. coli strains, including several enterohemorrhagic (EHEC) and enterotoxigenic (ETEC) E. coli strains. In this study, every strain from a genetically diverse panel of E. coli O157:H7 (n = 25) and additional strains of E. coli serovar O26 were susceptible to the PDI phenotype. LIVE/DEAD staining was consistent with inhibition by killing of susceptible cells. Comparative genome analysis identified the genetic component of PDI, which is composed of a plasmid-borne (Incl1) operon encoding a putative microcin and associated genes for transport, immunity, and microcin activation. Transfer of the plasmid to a PDI− strain resulted in transfer of the phenotype, and deletion of the genes within the operon resulted in loss of the inhibition phenotype. Deletion of chromosomally encoded tolC also resulted in loss of the inhibitory phenotype, and this confirmed that the putative microcin is most likely secreted via a type I secretion pathway. Deletion of an unrelated plasmid gene did not affect the PDI phenotype. Quantitative reverse transcription (RT)-PCR demonstrated that microcin expression is correlated with logarithmic-phase growth. The ability to inhibit a diversity of E. coli strains indicates that this microcin may influence gut community composition and could be useful for control of important enteric pathogens. PMID:22773653

  14. Being a Living Donor: Risks

    MedlinePlus

    ... Living Donation / Being a Living Donor / Risks Facts History Organs Frequently Asked Questions Discussing Living Donation Types Related Non-Related Non-Directed Paired Donation Blood Type Incompatible Positive Crossmatch Being a Living Donor ...

  15. Rotational tumbling of Escherichia coli aggregates under shear

    NASA Astrophysics Data System (ADS)

    Portela, R.; Patrício, P.; Almeida, P. L.; Sobral, R. G.; Franco, J. M.; Leal, C. R.

    2016-12-01

    Growing living cultures of Escherichia coli bacteria are investigated using real-time in situ rheology and rheoimaging measurements. In the early stages of growth (lag phase) and when subjected to a constant stationary shear, the viscosity slowly increases with the cell's population. As the bacteria reach the exponential phase of growth, the viscosity increases rapidly, with sudden and temporary abrupt decreases and recoveries. At a certain stage, corresponding grossly to the late phase of growth, when the population stabilizes, the viscosity also keeps its maximum constant value, with drops and recoveries, for a long period of time. This complex rheological behavior, which is observed to be shear strain dependent, is a consequence of two coupled effects: the cell density continuous increase and its changing interacting properties. Particular attention is given to the late phase of growth of E. coli populations under shear. Rheoimaging measurements reveal, near the static plate, a rotational motion of E. coli aggregates, collectively tumbling and flowing in the shear direction. This behavior is interpreted in the light of a simple theoretical approach based on simple rigid body mechanics.

  16. Multichromatic control of gene expression in Escherichia coli

    PubMed Central

    Tabor, Jeffrey J.; Levskaya, Anselm; Voigt, Christopher A.

    2010-01-01

    Light is a powerful tool for manipulating living cells because it can be applied with high resolution across space and over time. We previously constructed a red-light sensitive E. coli transcription system based on a chimera between the red/far red switchable cyanobacterial phytochrome Cph1 and the E. coli EnvZ/OmpR two-component signaling pathways. Here we report the development of a green light inducible transcription system in E. coli based on a recently discovered green/red photoswitchable two-component system from cyanobacteria. We demonstrate that transcriptional output is proportional to the intensity of green light applied and that the green sensor is orthogonal to the red sensor at intensities of 532nm light less than 0.01W/m2. Expression of both sensors in a single cell allows two-color optical control of transcription in both batch culture and in patterns across a lawn of engineered cells. Because each sensor functions as a photoreversible switch, this system should allow the spatial and temporal control of the expression of multiple genes though different combinations of light wavelengths. This feature should aid precision single cell and population-level studies in systems and synthetic biology. PMID:21035461

  17. Rotational tumbling of Escherichia coli aggregates under shear.

    PubMed

    Portela, R; Patrício, P; Almeida, P L; Sobral, R G; Franco, J M; Leal, C R

    2016-12-01

    Growing living cultures of Escherichia coli bacteria are investigated using real-time in situ rheology and rheoimaging measurements. In the early stages of growth (lag phase) and when subjected to a constant stationary shear, the viscosity slowly increases with the cell's population. As the bacteria reach the exponential phase of growth, the viscosity increases rapidly, with sudden and temporary abrupt decreases and recoveries. At a certain stage, corresponding grossly to the late phase of growth, when the population stabilizes, the viscosity also keeps its maximum constant value, with drops and recoveries, for a long period of time. This complex rheological behavior, which is observed to be shear strain dependent, is a consequence of two coupled effects: the cell density continuous increase and its changing interacting properties. Particular attention is given to the late phase of growth of E. coli populations under shear. Rheoimaging measurements reveal, near the static plate, a rotational motion of E. coli aggregates, collectively tumbling and flowing in the shear direction. This behavior is interpreted in the light of a simple theoretical approach based on simple rigid body mechanics.

  18. Occurrence of Escherichia coli in the Cuyahoga River in the Cuyahoga Valley National Park, Ohio

    USGS Publications Warehouse

    Brady, Amie M.G.; Plona, Meg B.

    2010-01-01

    There are several measures of the 'cleanliness' of a natural body of water, including concentrations of indicator bacteria, anthropogenic chemicals (chemicals derived from human activities), and nutrients, such as nitrogen and phosphorous. Escherichia coli (E. coli) is a bacterium that lives in the intestinal tract of warm-blooded animals, such as humans, deer, cows, and dogs. Most strains of E. coli are not harmful and are in fact beneficial to humans by aiding in the digestive process. A few strains, such as the O157 strain, produce toxins that can cause gastrointestinal illness, but occurrence of toxic strains in the environment is not common. E. coli is considered a good indicator bacterium because its occurrence in the environment indicates the presence of fecal contamination and therefore the possible presence of pathogenic organisms associated with feces. The U.S. Environmental Protection Agency (USEPA) recommends using measurements of E. coli to monitor freshwaters and set criteria for the concentration of bacteria that can be present in the water with minimal adverse human-health effects. Typically, a State's waters are assigned a recreational-use designation, such as bathing, primary-contact, or secondary contact waters, which is used to set the State's water-quality standards based on the USEPA criteria. The Cuyahoga River in the Cuyahoga Valley National Park is designated for primary-contact recreation; therefore, when concentrations of E. coli exceed 298 CFU/100mL, the river would be considered potentially unsafe for recreation.

  19. Multidrug-resistant pathogenic Escherichia coli isolated from wild birds in a veterinary hospital.

    PubMed

    Borges, C A; Beraldo, L G; Maluta, R P; Cardozo, M V; Barboza, K B; Guastalli, E A L; Kariyawasam, S; DebRoy, C; Ávila, F A

    2017-02-01

    Wild birds are carriers of Escherichia coli. However, little is known about their role as reservoirs for extra-intestinal pathogenic E. coli (ExPEC). In this work we investigated E. coli strains carrying virulence genes related to human and animal ExPEC isolated from free-living wild birds treated in a veterinary hospital. Multidrug resistance was found in 47.4% of the strains, but none of them were extended-spectrum beta-lactamase producers. Not only the virulence genes, but also the serogroups (e.g. O1 and O2) detected in the isolates of E. coli have already been implicated in human and bird diseases. The sequence types detected were also found in wild, companion and food animals, environmental and human clinical isolates in different countries. Furthermore, from the 19 isolates, 17 (89.5%) showed a degree of pathogenicity on an in vivo infection model. The isolates showed high heterogeneity by pulsed-field gel electrophoresis indicating that E. coli from these birds are clonally diverse. Overall, the results showed that wild birds can be reservoirs and/or vectors of highly pathogenic and multidrug-resistant E. coli that have the potential to cause disease in humans and poultry.

  20. Conformational Fluctuations of Chromosomal DNA in E. coli

    NASA Astrophysics Data System (ADS)

    Freeman, Clarissa; Meiners, Jens-Christian

    2012-02-01

    We measured the conformational fluctuations of the bacterial chromosome in E. Coli in vivo using fluorescence correlation spectroscopy (FCS). The chromosomal DNA was randomly decorated with a cell-permeable intercalating dye. Conformational fluctuations of the DNA move the fluorophores stochastically into the diffraction-limited excitation volume of a focused laser beam. The time correlation function of the fluorescence intensity reflects the underlying dynamics of the DNA on length scales down to ˜200 nm. A comparison between live cells and dead yet structurally intact cells shows identical fluctuation spectra for short time scales, yet substantial differences for frequencies below 100 Hz. Live cells show much stronger fluctuations in this regime. This observation points to the crucial importance of active molecular motor action, as opposed to passive thermal noise, in driving larger conformational fluctuations in the chromosomal DNA, in particular on length scales exceeding ˜500 nm.

  1. Living Willow Huts

    ERIC Educational Resources Information Center

    Keeler, Rusty

    2007-01-01

    Living Willow Huts are inexpensive to make, fun to plant, easy to grow, and make beautiful spaces for children. They involve planting dormant willow shoots in the ground and weaving them into shapes that will sprout and grow over time. People have been creating similar living architecture throughout the world for centuries in the forms of living…

  2. Living with Respiratory Failure

    MedlinePlus

    ... smoking. Emotional Issues and Support Living with respiratory failure may cause fear, anxiety, depression, and stress. Talk about how you feel with your health care team. Talking to a professional counselor also can ... to living with respiratory failure. You can see how other people who have ...

  3. Recognizing Safety and Liveness.

    DTIC Science & Technology

    1986-01-01

    in terms of "bad things" and "good things".* In [ Sistla 85], an attempt is made to give syntactic charcrizations for safety and live- ness properties...properris, and for a subset of the livene= proMe- ties, called absolute liveness propertie Fally, [ Sistla 85] proves that the states of a Buchi

  4. Living Willow Huts

    ERIC Educational Resources Information Center

    Keeler, Rusty

    2007-01-01

    Living Willow Huts are inexpensive to make, fun to plant, easy to grow, and make beautiful spaces for children. They involve planting dormant willow shoots in the ground and weaving them into shapes that will sprout and grow over time. People have been creating similar living architecture throughout the world for centuries in the forms of living…

  5. Robust growth of Escherichia coli.

    PubMed

    Wang, Ping; Robert, Lydia; Pelletier, James; Dang, Wei Lien; Taddei, Francois; Wright, Andrew; Jun, Suckjoon

    2010-06-22

    The quantitative study of the cell growth has led to many fundamental insights in our understanding of a wide range of subjects, from the cell cycle to senescence. Of particular importance is the growth rate, whose constancy represents a physiological steady state of an organism. Recent studies, however, suggest that the rate of elongation during exponential growth of bacterial cells decreases cumulatively with replicative age for both asymmetrically and symmetrically dividing organisms, implying that a "steady-state" population consists of individual cells that are never in a steady state of growth. To resolve this seeming paradoxical observation, we studied the long-term growth and division patterns of Escherichia coli cells by employing a microfluidic device designed to follow steady-state growth and division of a large number of cells at a defined reproductive age. Our analysis of approximately 10(5) individual cells reveals a remarkable stability of growth whereby the mother cell inherits the same pole for hundreds of generations. We further show that death of E. coli is not purely stochastic but is the result of accumulating damages. We conclude that E. coli, unlike all other aging model systems studied to date, has a robust mechanism of growth that is decoupled from cell death.

  6. A vaccine candidate for post-weaning diarrhea in swine constructed with a live attenuated Salmonella delivering Escherichia coli K88ab, K88ac, FedA, and FedF fimbrial antigens and its immune responses in a murine model.

    PubMed

    Hur, Jin; Stein, Barry D; Lee, John Hwa

    2012-07-01

    In order to construct a novel vaccine candidate for preventing post-weaning diarrhea in swine, the individual genes for Escherichia coli K88ab, K88ac, FedA, and FedF fimbriae were inserted into a secretion plasmid pBP244 containing asd, lepB, secA, and secB. These were transformed into Salmonella Typhimurium Δlon ΔcpxR Δasd. Secretion of the individual recombinant fimbrial antigens was confirmed by immunoblot analysis. Groups 1 and 2 mice received a single oral dose of the vaccine mixture and S. Typhimurium carrying pBP244 only as a control, respectively. In groups 3 and 4, mice were primed and boosted with the vaccine mixture and S. Typhimurium carrying pBP244 only as a control, respectively. In general, all immunized mice had significantly increased serum immunoglobulin (Ig)G (P < 0.05) and intestinal secretory IgA against the individual fimbrial antigens compared with those mice in the control group. In the IgG2a and IgG1 titer assay, only IgG2a titer was increased in group 1, while both IgG2a and IgG1 titers were increased in group 3. Furthermore, the vaccine strains were not detected in the excreted feces of any immunized mice. Thus, the vaccine candidate can be highly immunogenic and be safe to the environment.

  7. Engineering an Escherichia coli platform to synthesize designer biodiesels.

    PubMed

    Wierzbicki, Michael; Niraula, Narayan; Yarrabothula, Akshitha; Layton, Donovan S; Trinh, Cong T

    2016-04-20

    Biodiesels, fatty acid esters (FAEs), can be synthesized by condensation of fatty acid acyl CoAs and alcohols via a wax ester synthase in living cells. Biodiesels have advantageous characteristics over petrodiesels such as biodegradability, a higher flash point, and less emission. Controlling fatty acid and alcohol moieties are critical to produce designer biodiesels with desirable physiochemical properties (e.g., high cetane number, low kinematic viscosity, high oxidative stability, and low cloud point). Here, we developed a flexible framework to engineer Escherichia coli cell factories to synthesize designer biodiesels directly from fermentable sugars. In this framework, we designed each FAE pathway as a biodiesel exchangeable production module consisting of acyl CoA, alcohol, and wax ester synthase submodules. By inserting the FAE modules in an engineered E. coli modular chassis cell, we generated E. coli cell factories to produce targeted biodiesels (e.g., fatty acid ethyl (FAEE) and isobutyl (FAIbE) esters) with tunable and controllable short-chain alcohol moieties. The engineered E. coli chassis carrying the FAIbE production module produced 54mg/L FAIbEs with high specificity, accounting for>90% of the total synthesized FAEs and ∼4.7 fold increase in FAIbE production compared to the wildtype. Fed-batch cultures further improved FAIbE production up to 165mg/L. By mixing ethanol and isobutanol submodules, we demonstrated controllable production of mixed FAEEs and FAIbEs. We envision the developed framework offers a flexible, alternative route to engineer designer biodiesels with tunable and controllable properties using biomass-derived fermentable sugars. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. In Search of the E. coli Compounds that Change the Antibiotic Production Pattern of Streptomyces coelicolor During Inter-species Interaction.

    PubMed

    Mavituna, Ferda; Luti, Khalid Jaber Kadhum; Gu, Lixing

    2016-08-01

    The aim of this work was to investigate the interaction between E.coli and Streptomyces coelicolor A3 (2) for the increased production of undecylprodigiosin and identify the E. coli actives mediating this inter-species interaction. The antibiotics of interest were the red-pigmented undecylprodigiosin and blue-pigmented actinorhodin. Pure cultures of S. coelicolor in a defined medium produced higher concentrations of actinorhodin compared to those of undecylprodigiosin. The latter however, is more important due to its immunosuppressive and antitumor properties. As a strategy to increase undecylprodigiosin production, we added separately, live cells and heat-killed cells of E. coli C600, and the cell-free supernatant of E. coli culture to S. coelicolor cultures in shake flasks. The interaction with live cells of E. coli altered the antibiotic production pattern and undecylprodigiosin production was enhanced by 3.5-fold compared to the pure cultures of S. coelicolor and actinorhodin decreased by 15-fold. The heat-killed cells of E. coli however, had no effect on antibiotic production. In all cases, growth and glucose consumption of S. coelicolor remained almost the same as those observed in the pure culture indicating that the changes in antibiotic production were not due to nutritional stress. Results with cell-free supernatant of E. coli culture indicated that the interaction between S. coelicolor and E. coli was mediated via diffusible molecule(s). Using a set of extraction procedures and agar-well diffusion bioassays, we isolated and preliminarily identified a class of compounds. For the preliminary verification, we added the compound which was the common chemical structural moiety in this class of compounds to the pure S. coelicolor cultures. We observed similar effects on antibiotic production as with the live E. coli cells and their supernatant indicating that this class of compounds secreted by E. coli indeed could act as actives during interspecies

  9. Evaluation of the Control of Pathogen Load by an Anti-Salmonella Bacterium in a Herd of Cattle with Persistent Salmonella Infection

    USDA-ARS?s Scientific Manuscript database

    Objective: To isolate an anti-Salmonella bacterium that may control pathogen load in persistently-infected cattle herds. Animals: 24 Holstein calves. Procedures: An Escherchia coli (designated as P8E5) that possesses anti-Salmonella activity was isolated from Salmonella negative bovine feces ob...

  10. Temperature-dependent effect of sublethal levels of cinnamaldehyde on viability and morphology of Escherichia coli.

    PubMed

    Visvalingam, J; Holley, R A

    2012-09-01

    Effects of sublethal levels of cinnamaldehyde (CIN) on the viability and morphology of Escherichia coli O157:H7 and E. coli 8 WT were investigated at 6 and 37°C. The minimum inhibitory concentration of CIN against E. coli O157:H7 and E. coli 8WT was 400 mg l(-1). At 37°C and ≤300 mg l(-1), CIN delayed the multiplication of both strains, causing a ≤5 and ≤13 h lag, respectively. Delayed multiplication at ≤300 mg l(-1) was partly due to cell elongation and injury as determined by LIVE/DEAD viability, CTC vitality and bis-(1,3-dibutylbarbituric acid) trimethine oxonol staining. The greatest extent of cell elongation (87%) and greatest mean length (6.4 μm) occurred with E. coli O157:H7 at 2-h exposure to 200 mg l(-1) CIN. After initial delays in multiplication, both E. coli O157:H7 and E. coli 8WT returned to exponential growth and normal morphology before reaching the stationary phase. In contrast at 6°C, CIN at ≥100 mg l(-1) prevented cell elongation which occurred in untreated control cells. Treatment with 200 or 300 mg l(-1) CIN at 6°C was lethal to both E. coli strains. At 300 mg l(-1) , CIN caused a ≥5 log CFU ml(-1) reduction at ≤3 days and completely inactivated both of these organisms, causing ≥7 log CFU ml(-1) reduction at 7 days. Sublethal levels of CIN at 37°C delayed the multiplication of E. coli cells by causing transient cell elongation, but at 6°C ≥200 mg l(-1) CIN was lethal to E. coli. Inhibition of cold-induced cell elongation and the enhanced lethal effect of CIN at 6°C against E. coli O157:H7 suggest that CIN may be useful for control of this pathogen at refrigeration temperatures. © 2012 The Authors Journal of Applied Microbiology © 2012 The Society for Applied Microbiology.

  11. Chromosomal features of Escherichia coli serotype O2:K2, an avian pathogenic E. coli.

    PubMed

    Jørgensen, Steffen L; Kudirkiene, Egle; Li, Lili; Christensen, Jens P; Olsen, John E; Nolan, Lisa; Olsen, Rikke H

    2017-01-01

    Escherichia coli causing infection outside the gastrointestinal system are referred to as extra-intestinal pathogenic E. coli. Avian pathogenic E. coli is a subgroup of extra-intestinal pathogenic E. coli and infections due to avian pathogenic E. coli have major impact on poultry production economy and welfare worldwide. An almost defining characteristic of avian pathogenic E. coli is the carriage of plasmids, which may encode virulence factors and antibiotic resistance determinates. For the same reason, plasmids of avian pathogenic E. coli have been intensively studied. However, genes encoded by the chromosome may also be important for disease manifestation and antimicrobial resistance. For the E. coli strain APEC_O2 the plasmids have been sequenced and analyzed in several studies, and E. coli APEC_O2 may therefore serve as a reference strain in future studies. Here we describe the chromosomal features of E. coli APEC_O2. E. coli APEC_O2 is a sequence type ST135, has a chromosome of 4,908,820 bp (plasmid removed), comprising 4672 protein-coding genes, 110 RNA genes, and 156 pseudogenes, with an average G + C content of 50.69%. We identified 82 insertion sequences as well as 4672 protein coding sequences, 12 predicated genomic islands, three prophage-related sequences, and two clustered regularly interspaced short palindromic repeats regions on the chromosome, suggesting the possible occurrence of horizontal gene transfer in this strain. The wildtype strain of E. coli APEC_O2 is resistant towards multiple antimicrobials, however, no (complete) antibiotic resistance genes were present on the chromosome, but a number of genes associated with extra-intestinal disease were identified. Together, the information provided here on E. coli APEC_O2 will assist in future studies of avian pathogenic E. coli strains, in particular regarding strain of E. coli APEC_O2, and aid in the general understanding of the pathogenesis of avian pathogenic E. coli.

  12. Transcription of foreign DNA in Escherichia coli.

    PubMed

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

    2008-11-01

    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 sigma(70) (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.

  13. Presence of Shiga toxin-producing Escherichia coli, Enteroinvasive E. coli, Enteropathogenic E. coli, and Enterotoxigenic E. coli on tomatoes from public markets in Mexico.

    PubMed

    Gómez-Aldapa, Carlos A; Torres-Vitela, M Del Refugio; Acevedo-Sandoval, Otilio A; Rangel-Vargas, Esmeralda; Villarruel-López, Angélica; Castro-Rosas, Andjavier

    2013-09-01

    Diarrheagenic Escherichia coli pathotypes (DEP) are important foodborne pathogens in various countries, including Mexico. However, no data exist on the presence of DEP on fresh tomatoes (Solanum lycopericum) from Mexico. The frequency of fecal coliforms (FC), E. coli, and DEP were determined for two tomato varieties. One hundred samples of a saladette tomato variety and 100 samples of a red round tomato variety were collected from public markets in Pachuca, Mexico. Each tomato sample consisted of four whole tomatoes. For the 100 saladette samples, coliform bacterial, FC, E. coli, and DEP were identified in 100, 70, 60, and 10% of samples, respectively. For the 100 red round samples, coliform bacterial, FC, E. coli, and DEP were identified in 100, 75, 65, and 11% of samples, respectively. Identified DEP included Shiga toxin-producing E. coli (STEC), enteroinvasive E. coli (EIEC), enteropathogenic E. coli (EPEC), and enterotoxigenic E. coli (ETEC). STEC were isolated from 6% of saladette samples and 5% of red round samples. ETEC were isolated from 3% of saladette samples and 4% of red round samples. EPEC were isolated from 2% of saladette samples and 3% of red round samples, and EIEC were isolated from 1% of saladette samples. Both STEC and ETEC were identified in two saladette samples and 1 red round sample. E. coli O157:H7 was not detected in any STEC-positive samples.

  14. Proofreading in vivo: Editing of homocysteine by methionyl-tRNA synthetase in Escherichia coli

    SciTech Connect

    Jakubowski, H. )

    1990-06-01

    Previous in vitro studies have established a pre-transfer proofreading mechanism for editing of homocysteine by bacterial methionyl-, isoleucyl-, and valyl-tRNA synthetases. The unusual feature of the editing is the formation of a distinct compound, homocysteine thiolactone. Now, two-dimensional TLC analysis of 35S-labeled amino acids extracted from cultures of the bacterium Escherichia coli reveals that the thiolactone is also synthesized in vivo. In E. coli, the thiolactone is made from homocysteine in a reaction catalyzed by methionyl-tRNA synthetase. One molecule of homocysteine is edited as thiolactone per 109 molecules of methionine incorporated into protein in vivo. These results not only directly demonstrate that the adenylate proofreading pathway for rejection of misactivated homocysteine operates in vivo in E. coli but, in general, establish the importance of error-editing mechanisms in living cells.

  15. Double-Staining Method for Differentiation of Morphological Changes and Membrane Integrity of Campylobacter coli Cells

    PubMed Central

    Alonso, Jose L.; Mascellaro, Salvatore; Moreno, Yolanda; Ferrús, María A.; Hernández, Javier

    2002-01-01

    We developed a double-staining procedure involving NanoOrange dye (Molecular Probes, Eugene, Oreg.) and membrane integrity stains (LIVE/DEAD BacLight kit; Molecular Probes) to show the morphological and membrane integrity changes of Campylobacter coli cells during growth. The conversion from a spiral to a coccoid morphology via intermediary forms and the membrane integrity changes of the C. coli cells can be detected with the double-staining procedure. Our data indicate that young or actively growing cells are mainly spiral shaped (green-stained cells), but older cells undergo a degenerative change to coccoid forms (red-stained cells). Club-shaped transition cell forms were observed with NanoOrange stain. Chlorinated drinking water affected the viability but not the morphology of C. coli cells. PMID:12324366

  16. Converting carbohydrates extracted from marine algae into ethanol using various ethanolic Escherichia coli strains.

    PubMed

    Lee, Soojin; Oh, Younghoon; Kim, Donghyun; Kwon, Doyeon; Lee, Choulgyun; Lee, Jinwon

    2011-07-01

    Marine algae, which make up about 80% of the world's living organisms, contain many energy sources, such as sugars and lipids. Therefore, the possibility of utilizing structural carbohydrates from marine algae for bioethanol production has been studied. In order to obtain monosaccharides, Undaria pinnatifida, Chlorella vulgaris, and Chlamydomonas reinhardtii were used for the saccharification experiments. The pretreatment was carried out by dilute acid hydrolysis and enzymatic treatment. To find the optimal conditions, experiments were performed at several temperatures, acid concentrations, pH conditions and durations. To test bioethanol production, several ethanolic E. coli W3110 strains, which were developed previously, were used. The maximum yield of bioethanol, 0.4 g ethanol/g biomass, was achieved with pretreated C. vulgaris and E. coli SJL2526, derived from wild-type E. coli W3110 and which includes the adhB, pdc, galP, and glk genes.

  17. Proofreading in vivo: editing of homocysteine by methionyl-tRNA synthetase in Escherichia coli.

    PubMed Central

    Jakubowski, H

    1990-01-01

    Previous in vitro studies have established a pre-transfer proofreading mechanism for editing of homocysteine by bacterial methionyl-, isoleucyl-, and valyl-tRNA synthetases. The unusual feature of the editing is the formation of a distinct compound, homocysteine thiolactone. Now, two-dimensional TLC analysis of 35S-labeled amino acids extracted from cultures of the bacterium Escherichia coli reveals that the thiolactone is also synthesized in vivo. In E. coli, the thiolactone is made from homocysteine in a reaction catalyzed by methionyl-tRNA synthetase. One molecule of homocysteine is edited as thiolactone per 109 molecules of methionine incorporated into protein in vivo. These results not only directly demonstrate that the adenylate proofreading pathway for rejection of misactivated homocysteine operates in vivo in E. coli but, in general, establish the importance of error-editing mechanisms in living cells. Images PMID:2191291

  18. GFP-tagged E. coli shows bacterial distribution in mouse organs: pathogen tracking using fluorescence signal

    PubMed Central

    Park, Pil-Gu; Cho, Min-Hee; Rhie, Gi-eun; Jeong, Haeseul; Youn, Hyewon

    2012-01-01

    Purpose In vaccine efficacy evaluation, visualization of pathogens in whole organism at each time point would be able to reduce the consuming animals and provide the in vivo information within consistent background with identical organism. Materials and Methods Using IVIS spectrum whole live-animal imaging system, fluorescent intensity was optimized and visualized proportionately by concentrating Escherichia coli MC1061 strain which expresses GFP (E. coli-GFP) in BALB/C mice after injection. Results Local distribution of disseminated E. coli-GFP was traced in each organ by fluorescence. Detached organ showed more obvious fluorescent signal, and intestine showed strongest fluorescent signal. Conclusion This in vivo imaging method using GFP-tagged pathogen strain suggest quantified infected pathogens by fluorescence intensity in whole animals can provide the information about the localization and distribution after infection. PMID:23596581

  19. Biofilm exclusion of uropathogenic bacteria by selected asymptomatic bacteriuria Escherichia coli strains.

    PubMed

    Ferrières, Lionel; Hancock, Viktoria; Klemm, Per

    2007-06-01

    Many bacterial infections are associated with biofilm formation. In the urinary tract bacterial biofilms develop on both living surfaces and artificial implants, producing chronic and often intractable infections. Escherichia coli is the most common organism associated with urinary tract infections. In contrast to uropathogenic E. coli (UPEC), which cause symptomatic urinary tract infection, asymptomatic bacteriuria (ABU) strains are associated with essentially symptom-free infections. Here the biofilm-forming capacity on abiotic surfaces of selected E. coli ABU strains and UPEC strains in human urine was investigated. It was found that there is a strong bias for biofilm formation by the ABU strains. Not only were the ABU strains significantly better biofilm formers than UPEC strains, they were also able to out-compete UPEC strains as well as uropathogenic strains of Klebsiella spp. during biofilm formation. The results support the notion of bacterial prophylaxis employing selected ABU strains to eliminate UPEC strains and other pathogens in patients prone to recalcitrant infections.

  20. Living with Hearing Loss

    MedlinePlus

    ... Current Issue Past Issues Special Section: Focus on Communication Living with Hearing Loss Past Issues / Fall 2008 ... the United States suffer some form of disordered communication. The National Institute on Deafness and Other Communication ...

  1. Living with Stepparents

    MedlinePlus

    ... get divorced . This is never an easy decision. Divorce can be painful for parents, but eventually, each ... ON THIS TOPIC Kids Talk About: Marriage and Divorce (Video) Living With a Single Parent Foster Families ...

  2. Living Beyond Breast Cancer

    MedlinePlus

    ... Types of Complementary Therapy Acupuncture Art Therapy Expressive Writing Guided Imagery Hypnosis Massage Therapy Mindfulness-Based Stress ... Conference Past Conferences Meet-Ups Twitter Chats Webinars Writing Workshops Young Women's Initiative Fundraising Events Galas Living ...

  3. Living with Bronchopulmonary Dysplasia

    MedlinePlus

    ... Living With Bronchopulmonary Dysplasia Caring for a premature infant can be challenging. You may have: Emotional pain, ... tiredness). Frustration that you can't breastfeed your infant right away. (You can pump and store your ...

  4. Living with COPD: Nutrition

    MedlinePlus

    ... Diseases > Lung Disease Lookup > COPD > Living With COPD Nutrition Most people are surprised to learn that the ... asking your doctor or visiting the Academy of Nutrition and Dietetics at EatRight.org . Be sure to ...

  5. Thalassemia: Healthy Living

    MedlinePlus

    ... severe anemia and possible organ damage from iron overload, respectively. Healthy Choices for People Living with Thalassemia ... Center on Birth Defects and Developmental Disabilities Related Information UDC System File Formats Help: How do I ...

  6. Living with Paralysis

    MedlinePlus

    ... are available to answer your questions. Call toll-free 1-800-539-7309 Mon-Fri, 9am-5pm ... are people living with or impacted by paralysis. Free services and downloads > Paralysis Resource Guide Our free ...

  7. Fluorescence Live Cell Imaging

    PubMed Central

    Ettinger, Andreas

    2014-01-01

    Fluorescence microscopy of live cells has become an integral part of modern cell biology. Fluorescent protein tags, live cell dyes, and other methods to fluorescently label proteins of interest provide a range of tools to investigate virtually any cellular process under the microscope. The two main experimental challenges in collecting meaningful live cell microscopy data are to minimize photodamage while retaining a useful signal-to-noise ratio, and to provide a suitable environment for cells or tissues to replicate physiological cell dynamics. This chapter aims to give a general overview on microscope design choices critical for fluorescence live cell imaging that apply to most fluorescence microscopy modalities, and on environmental control with a focus on mammalian tissue culture cells. In addition, we provide guidance on how to design and evaluate fluorescent protein constructs by spinning disk confocal microscopy. PMID:24974023

  8. Hand Hygiene Saves Lives

    MedlinePlus

    ... at Home Smoke-free Multiunit Housing The Quiet Killer Healthy Living Healthy Eating A Grocery Store’s Healthy ... Things Safe Teen Drivers Life Stages & Populations A Killer in Indian Country Baby Steps: Learn the Signs. ...

  9. Living with Pulmonary Embolism

    MedlinePlus

    ... on Twitter. Living With Pulmonary Embolism Pulmonary embolism (PE) usually is treated in a hospital. After leaving ... you're taking medicine. Medicines used to treat PE can thin your blood too much. This can ...

  10. Living with Fanconi Anemia

    MedlinePlus

    ... from the NHLBI on Twitter. Living With Fanconi Anemia Improvements in blood and marrow stem cell transplants ... November 1, 2011 Twitter Facebook YouTube Google+ SITE INDEX ACCESSIBILITY PRIVACY STATEMENT FOIA NO FEAR ACT OIG ...

  11. Live Virus Smallpox Vaccine

    MedlinePlus

    ... Submit What's this? Submit Button The Live Virus Smallpox Vaccine Language: English Español (Spanish) Recommend on Facebook ... the vaccinia virus. Who should NOT get the smallpox vaccine? People most likely to have side effects ...

  12. Living Day by Day

    PubMed Central

    Kaplan, Rachel L.; Khoury, Cynthia El; Field, Emily R. S.; Mokhbat, Jacques

    2016-01-01

    We examined the meaning of living with HIV/AIDS among women in Lebanon. Ten women living with HIV/AIDS (WLWHA) described their experiences via semistructured in-depth interviews. They navigated a process of HIV diagnosis acceptance that incorporated six overlapping elements: receiving the news, accessing care, starting treatment, navigating disclosure decisions, negotiating stigma, and maintaining stability. Through these elements, we provide a framework for understanding three major themes that were constructed during data analysis: Stand by my side: Decisions of disclosure; Being “sick” and feeling “normal”: Interacting with self, others, and society; and Living day by day: focusing on the present. We contribute to the existing literature by providing a theoretical framework for understanding the process of diagnosis and sero-status acceptance among WLWHA. This was the first study of its kind to examine the meaning of living with HIV/AIDS among women in a Middle Eastern country. PMID:28462340

  13. Influenza Vaccine, Live Intranasal

    MedlinePlus

    ... the recombinant influenza vaccine (RIV). The nasal spray flu vaccine (live attenuated influenza vaccine or LAIV) should NOT ... to your doctor or pharmacist about the best flu vaccine option for you or your family.

  14. Healthy Living after Stroke

    MedlinePlus

    ... Stories Stroke Heroes Among Us Healthy Living After Stroke Nutrition Good nutrition is one way to reduce ... reviewed on 04/30/2014. Register for the Stroke Rehab Webinar Join rehab experts as they discuss ...

  15. ASHRAE's Living Laboratory

    SciTech Connect

    Jarnagin, Ronald E.; Brambley, Michael R.

    2008-10-01

    ASHRAE recently remodeled its headquarters building in Atlanta with the intention of making the building a LEED Gold building. As part of that renovation the building was enhanced with additional sensors and monitoring equipment to allow it to serve as a Living Laboratory for use by members and the general public to study the detailed energy use and performance of buildings. This article provides an overview of the Living Laboratory and its capabilities.

  16. Annual Surveillance Summary: Escherichia coli (E. coli) Infections in the Military Health System (MHS), 2016

    DTIC Science & Technology

    2017-06-30

    women.5 Screening practices may also contribute to higher rates of E. coli infections among females of reproductive age, as the Infectious Disease...Annual Surveillance Summary: Escherichia coli (E. coli) Infections in the Military Health System (MHS...and prevalence among all beneficiaries seeking care within the Military Health System (MHS). This report describes demographics, clinical

  17. Growth of Mycobacterium avium subsp. paratuberculosis, Escherichia coli, and Salmonella Enteritidis during Preparation and Storage of Yogurt

    PubMed Central

    Cirone, K.; Huberman, Y.; Morsella, C.; Méndez, L.; Jorge, M.; Paolicchi, F.

    2013-01-01

    The purpose of this study was to determine the viability of Mycobacterium avium subsp. paratuberculosis (MAP), Escherichia coli (E. coli), and Salmonella Enteritidis (S. Enteritidis) during preparation and refrigerated storage of yogurt. Three yogurts were prepared using pasteurized commercial milk. Each yogurt was artificially contaminated with (1) MAP, (2) E. coli + S. Enteritidis, and (3) MAP + E. coli + S. Enteritidis. Samples were taken during and after the fermentation process until day 20 after inoculation. MAP was not detected during their preparation and short-term storage but was recuperated after starting at 180 min after inoculation storage. Live bacterial counts of E. coli, and S. Enteritidis increased during the first 24 hours, followed by a slight decrease towards the end of the study. In this study it was shown how MAP, E. coli, and S. Enteritidis resisted the acidic conditions generated during the preparation of yogurt and low storage temperatures. This work contributes to current knowledge regarding survival of MAP, E. coli, and S. Enteritidis during preparation and refrigerated storage of yogurt and emphasizes the need to improve hygiene measures to ensure the absence of these pathogenic microorganisms in dairy products. PMID:24455399

  18. Evaluation of recombinant invasive, non-pathogenic Eschericia coli as a vaccine vector against the intracellular pathogen, Brucella

    PubMed Central

    Harms, Jerome S; Durward, Marina A; Magnani, Diogo M; Splitter, Gary A

    2009-01-01

    Background There is no safe, effective human vaccine against brucellosis. Live attenuated Brucella strains are widely used to vaccinate animals. However these live Brucella vaccines can cause disease and are unsafe for humans. Killed Brucella or subunit vaccines are not effective in eliciting long term protection. In this study, we evaluate an approach using a live, non-pathogenic bacteria (E. coli) genetically engineered to mimic the brucellae pathway of infection and present antigens for an appropriate cytolitic T cell response. Methods E. coli was modified to express invasin of Yersinia and listerialysin O (LLO) of Listeria to impart the necessary infectivity and antigen releasing traits of the intracellular pathogen, Brucella. This modified E. coli was considered our vaccine delivery system and was engineered to express Green Fluorescent Protein (GFP) or Brucella antigens for in vitro and in vivo immunological studies including cytokine profiling and cytotoxicity assays. Results The E. coli vaccine vector was able to infect all cells tested and efficiently deliver therapeutics to the host cell. Using GFP as antigen, we demonstrate that the E. coli vaccine vector elicits a Th1 cytokine profile in both primary and secondary immune responses. Additionally, using this vector to deliver a Brucella antigen, we demonstrate the ability of the E. coli vaccine vector to induce specific Cytotoxic T Lymphocytes (CTLs). Conclusion Protection against most intracellular bacterial pathogens can be obtained mostly through cell mediated immunity. Data presented here suggest modified E. coli can be used as a vaccine vector for delivery of antigens and therapeutics mimicking the infection of the pathogen and inducing cell mediated immunity to that pathogen. PMID:19126207

  19. Biocompatible click chemistry enabled compartment-specific pH measurement inside E. coli.

    PubMed

    Yang, Maiyun; Jalloh, Abubakar S; Wei, Wei; Zhao, Jing; Wu, Peng; Chen, Peng R

    2014-09-19

    Bioorthogonal reactions, especially the Cu(I)-catalysed azide-alkyne cycloaddition, have revolutionized our ability to label and manipulate biomolecules under living conditions. The cytotoxicity of Cu(I) ions, however, has hindered the application of this reaction in the internal space of living cells. By systematically surveying a panel of Cu(I)-stabilizing ligands in promoting protein labelling within the cytoplasm of Escherichia coli, we identify a highly efficient and biocompatible catalyst for intracellular modification of proteins by azide-alkyne cycloaddition. This reaction permits us to conjugate an environment-sensitive fluorophore site specifically onto HdeA, an acid-stress chaperone that adopts pH-dependent conformational changes, in both the periplasm and cytoplasm of E. coli. The resulting protein-fluorophore hybrid pH indicators enable compartment-specific pH measurement to determine the pH gradient across the E. coli cytoplasmic membrane. This construct also allows the measurement of E. coli transmembrane potential, and the determination of the proton motive force across its inner membrane under normal and acid-stress conditions.

  20. 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

  1. HU-GFP and DAPI co-localize on the Escherichia coli nucleoid.

    PubMed

    Wery, M; Woldringh, C L; Rouviere-Yaniv, J

    2001-02-01

    The heterodimeric HU protein, one of the most abundant DNA binding proteins, plays a pleiotropic role in bacteria. Among others, HU was shown to contribute to the maintenance of DNA superhelical density in Escherichia coli. By its properties HU shares some traits with histones and HMG proteins. More recently, its specific binding to DNA recombination and repair intermediates suggests that HU should be considered as a DNA damage sensor. For all these reasons, it will be of interest to follow the localization of HU within the living bacterial cells. To this end, we constructed HU-GFP fusion proteins and compared by microscopy the GFP green fluorescence with images of the nucleoid after DAPI staining. We show that DAPI and HU-GFP colocalize on the E. coli nucleoid. HU, therefore, can be considered as a natural tracer of DNA in the living bacterial cell.

  2. Epidemiological survey of the enteropathogenic Escherichia coli isolated from children with diarrhoea.

    PubMed

    Regua, A H; Bravo, V L; Leal, M C; Lobo Leite, M E

    1990-08-01

    Escherichia coli was isolated in 382 (94 per cent) of 406 children from 0 to 3 years of age who had been hospitalized for diarrhoea at the Hospital Municipal Salles Neto, Rio de Janeiro. Enteropathogenic Escherichia coli strains were isolated in 67 samples (18 per cent), distributed among the serogroups that were tested as follows: 0111 (33 per cent); 0125 (19 per cent); 0126, 0127, and 0142 (9 per cent); 0128 and 0119 (8 per cent); 055 (5 per cent); 0114 (2 per cent). No strains of EPEC belonging to serogroups 086, 0126, and 0158 were found. Among the samples in which EPEC strains were isolated, 15.0 per cent were children living in dwellings which had piped systems of water supply and drain, whereas with regard to those living in houses without such facilities, this percentage raised to 24 per cent. Similar results were found when the availability of water supply of drainage were taken separately.

  3. Localization of Protein Aggregation in Escherichia coli Is Governed by Diffusion and Nucleoid Macromolecular Crowding Effect

    PubMed Central

    Coquel, Anne-Sophie; Jacob, Jean-Pascal; Primet, Mael; Demarez, Alice; Dimiccoli, Mariella; Julou, Thomas; Moisan, Lionel

    2013-01-01

    Aggregates of misfolded proteins are a hallmark of many age-related diseases. Recently, they have been linked to aging of Escherichia coli (E. coli) where protein aggregates accumulate at the old pole region of the aging bacterium. Because of the potential of E. coli as a model organism, elucidating aging and protein aggregation in this bacterium may pave the way to significant advances in our global understanding of aging. A first obstacle along this path is to decipher the mechanisms by which protein aggregates are targeted to specific intercellular locations. Here, using an integrated approach based on individual-based modeling, time-lapse fluorescence microscopy and automated image analysis, we show that the movement of aging-related protein aggregates in E. coli is purely diffusive (Brownian). Using single-particle tracking of protein aggregates in live E. coli cells, we estimated the average size and diffusion constant of the aggregates. Our results provide evidence that the aggregates passively diffuse within the cell, with diffusion constants that depend on their size in agreement with the Stokes-Einstein law. However, the aggregate displacements along the cell long axis are confined to a region that roughly corresponds to the nucleoid-free space in the cell pole, thus confirming the importance of increased macromolecular crowding in the nucleoids. We thus used 3D individual-based modeling to show that these three ingredients (diffusion, aggregation and diffusion hindrance in the nucleoids) are sufficient and necessary to reproduce the available experimental data on aggregate localization in the cells. Taken together, our results strongly support the hypothesis that the localization of aging-related protein aggregates in the poles of E. coli results from the coupling of passive diffusion-aggregation with spatially non-homogeneous macromolecular crowding. They further support the importance of “soft” intracellular structuring (based on macromolecular

  4. Localization of protein aggregation in Escherichia coli is governed by diffusion and nucleoid macromolecular crowding effect.

    PubMed

    Coquel, Anne-Sophie; Jacob, Jean-Pascal; Primet, Mael; Demarez, Alice; Dimiccoli, Mariella; Julou, Thomas; Moisan, Lionel; Lindner, Ariel B; Berry, Hugues

    2013-04-01

    Aggregates of misfolded proteins are a hallmark of many age-related diseases. Recently, they have been linked to aging of Escherichia coli (E. coli) where protein aggregates accumulate at the old pole region of the aging bacterium. Because of the potential of E. coli as a model organism, elucidating aging and protein aggregation in this bacterium may pave the way to significant advances in our global understanding of aging. A first obstacle along this path is to decipher the mechanisms by which protein aggregates are targeted to specific intercellular locations. Here, using an integrated approach based on individual-based modeling, time-lapse fluorescence microscopy and automated image analysis, we show that the movement of aging-related protein aggregates in E. coli is purely diffusive (Brownian). Using single-particle tracking of protein aggregates in live E. coli cells, we estimated the average size and diffusion constant of the aggregates. Our results provide evidence that the aggregates passively diffuse within the cell, with diffusion constants that depend on their size in agreement with the Stokes-Einstein law. However, the aggregate displacements along the cell long axis are confined to a region that roughly corresponds to the nucleoid-free space in the cell pole, thus confirming the importance of increased macromolecular crowding in the nucleoids. We thus used 3D individual-based modeling to show that these three ingredients (diffusion, aggregation and diffusion hindrance in the nucleoids) are sufficient and necessary to reproduce the available experimental data on aggregate localization in the cells. Taken together, our results strongly support the hypothesis that the localization of aging-related protein aggregates in the poles of E. coli results from the coupling of passive diffusion-aggregation with spatially non-homogeneous macromolecular crowding. They further support the importance of "soft" intracellular structuring (based on macromolecular

  5. Preparation of Sticky Escherichia coli through Surface Display of an Adhesive Catecholamine Moiety

    PubMed Central

    Park, Joseph P.; Choi, Min-Jung; Kim, Se Hun

    2014-01-01

    Mussels attach to virtually all types of inorganic and organic surfaces in aqueous environments, and catecholamines composed of 3,4-dihydroxy-l-phenylalanine (DOPA), lysine, and histidine in mussel adhesive proteins play a key role in the robust adhesion. DOPA is an unusual catecholic amino acid, and its side chain is called catechol. In this study, we displayed the adhesive moiety of DOPA-histidine on Escherichia coli surfaces using outer membrane protein W as an anchoring motif for the first time. Localization of catecholamines on the cell surface was confirmed by Western blot and immunofluorescence microscopy. Furthermore, cell-to-cell cohesion (i.e., cellular aggregation) induced by the displayed catecholamine and synthesis of gold nanoparticles on the cell surface support functional display of adhesive catecholamines. The engineered E. coli exhibited significant adhesion onto various material surfaces, including silica and glass microparticles, gold, titanium, silicon, poly(ethylene terephthalate), poly(urethane), and poly(dimethylsiloxane). The uniqueness of this approach utilizing the engineered sticky E. coli is that no chemistry for cell attachment are necessary, and the ability of spontaneous E. coli attachment allows one to immobilize the cells on challenging material surfaces such as synthetic polymers. Therefore, we envision that mussel-inspired catecholamine yielded sticky E. coli that can be used as a new type of engineered microbe for various emerging fields, such as whole living cell attachment on versatile material surfaces, cell-to-cell communication systems, and many others. PMID:24123747

  6. Tellurite-exposed Escherichia coli exhibits increased intracellular {alpha}-ketoglutarate

    SciTech Connect

    Reinoso, Claudia A.; Auger, Christopher; Appanna, Vasu D.; Vasquez, Claudio C.

    2012-05-18

    Highlights: Black-Right-Pointing-Pointer Tellurite-exposed E. coli exhibits decreased {alpha}-KG dehydrogenase activity. Black-Right-Pointing-Pointer Cells lacking {alpha}-KGDH genes are more sensitive to ROS than isogenic, wt E. coli. Black-Right-Pointing-Pointer KG accumulation may serve to face tellurite-mediated oxidative damage in E. coli. -- Abstract: The tellurium oxyanion tellurite is toxic to most organisms because of its ability to generate oxidative stress. However, the detailed mechanism(s) how this toxicant interferes with cellular processes have yet to be fully understood. As part of our effort to decipher the molecular interactions of tellurite with living systems, we have evaluated the global metabolism of {alpha}-ketoglutarate a known antioxidant in Escherichia coli. Tellurite-exposed cells displayed reduced activity of the KG dehydrogenase complex (KGDHc), resulting in increased intracellular KG content. This complex's reduced activity seems to be due to decreased transcription in the stressed cells of sucA, a gene that encodes the E1 component of KGDHc. Furthermore, it was demonstrated that the increase in total reactive oxygen species and superoxide observed upon tellurite exposure was more evident in wild type cells than in E. coli with impaired KGDHc activity. These results indicate that KG may be playing a pivotal role in combating tellurite-mediated oxidative damage.

  7. Escherichia coli induces DNA damage in vivo and triggers genomic instability in mammalian cells

    PubMed Central

    Cuevas-Ramos, Gabriel; Petit, Claude R.; Marcq, Ingrid; Boury, Michèle; Oswald, Eric; Nougayrède, Jean-Philippe

    2010-01-01

    Escherichia coli is a normal inhabitant of the human gut. However, E. coli strains of phylogenetic group B2 harbor a genomic island called “pks” that codes for the production of a polyketide-peptide genotoxin, Colibactin. Here we report that in vivo infection with E. coli harboring the pks island, but not with a pks isogenic mutant, induced the formation of phosphorylated H2AX foci in mouse enterocytes. We show that a single, short exposure of cultured mammalian epithelial cells to live pks+ E. coli at low infectious doses induced a transient DNA damage response followed by cell division with signs of incomplete DNA repair, leading to anaphase bridges and chromosome aberrations. Micronuclei, aneuploidy, ring chromosomes, and anaphase bridges persisted in dividing cells up to 21 d after infection, indicating occurrence of breakage–fusion–bridge cycles and chromosomal instability. Exposed cells exhibited a significant increase in gene mutation frequency and anchorage-independent colony formation, demonstrating the infection mutagenic and transforming potential. Therefore, colon colonization with these E. coli strains harboring the pks island could contribute to the development of sporadic colorectal cancer. PMID:20534522

  8. Third International E. coli genome meeting

    SciTech Connect

    1994-12-31

    Proceedings of the Third E. Coli Genome Meeting are provided. Presentations were divided into sessions entitled (1) Large Scale Sequencing, Sequence Analysis; (2) Databases; (3) Sequence Analysis; (4) Sequence Divergence in E. coli Strains; (5) Repeated Sequences and Regulatory Motifs; (6) Mutations, Rearrangements and Stress Responses; and (7) Origins of New Genes. The document provides a collection of abstracts of oral and poster presentations.

  9. E. coli survival in waters: temperature dependence

    USDA-ARS?s Scientific Manuscript database

    Knowing the survival rates of water-borne Escherichia coli is important for evaluating microbial contamination and in making appropriate management decisions. E. coli survival rates are dependent on temperature; this dependency is routinely expressed using an analog of the Q10 model. This suggestion...

  10. 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...

  11. 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…

  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. 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...

  14. ISOLATION AND MOLECULAR IDENTIFICATION OF POTENTIALLY PATHOGENIC Escherichia coli AND Campylobacter jejuni IN FERAL PIGEONS FROM AN URBAN AREA IN THE CITY OF LIMA, PERU.

    PubMed

    Caballero, Moisés; Rivera, Isabel; Jara, Luis M; Ulloa-Stanojlovic, Francisco M; Shiva, Carlos

    2015-01-01

    Feral pigeons (Columbia livia) live in close contact with humans and other animals. They can transmit potentially pathogenic and zoonotic agents. The objective of this study was to isolate and detect strains of diarrheagenic Escherichia coli and Campylobacter jejuni of urban feral pigeons from an area of Lima, Peru. Fresh dropping samples from urban parks were collected for microbiological isolation of E. coli strains in selective agar, and Campylobacter by filtration method. Molecular identification of diarrheagenic pathotypes of E.coli and Campylobacter jejuni was performed by PCR. Twenty-two parks were sampled and 16 colonies of Campylobacter spp. were isolated. The 100% of isolates were identified as Campylobacter jejuni. Furthermore, 102 colonies of E. coli were isolated and the 5.88% resulted as Enteropathogenic (EPEC) type and 0.98% as Shiga toxin-producing E. coli (STEC). The urban feral pigeons of Lima in Peru can act as a reservoir or carriers of zoonotic potentially pathogenic enteric agents.

  15. 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

  16. Guiding E.coli to nanosensors

    NASA Astrophysics Data System (ADS)

    Park, Dong-Won; So, Hye-Mi; Kim, Beom Soo; Kong, Ki-Jeong; Chang, Hyunju; Lee, Jeong-O.

    2009-03-01

    Electronic nanosensors based on nanomaterials such as carbon nanotubes and nanowires are expected to have ultimate sensitivity. However, as an inherent problem of nanosensors, they have extremely small sensor surface for reaction. Therefore, simple diffusion of target biomolecules is not enough for such nanosensors, and the problem is even more serious in the case of motile bacteria. Previously, we have shown that we could estimate the titer of E.coli with arrays of single-walled carbon nanotube field effect transistors (SWNT-FET) combined with statistical method. Still, sensitivity of our method is inferior compared with incubation method, due to the limited sensor surface area. In this work, we actively guide E.coli to the sensor surface using micro-fabricated channels. Arrow-shaped and funnel shaped microstructures were fabricated in the channel to guide E. coli to the sensor surface, and we used green fluorescent protein expressed E.coli to monitor the guiding of E.coli.

  17. Living-cell microarrays.

    PubMed

    Yarmush, Martin L; King, Kevin R

    2009-01-01

    Living cells are remarkably complex. To unravel this complexity, living-cell assays have been developed that allow delivery of experimental stimuli and measurement of the resulting cellular responses. High-throughput adaptations of these assays, known as living-cell microarrays, which are based on microtiter plates, high-density spotting, microfabrication, and microfluidics technologies, are being developed for two general applications: (a) to screen large-scale chemical and genomic libraries and (b) to systematically investigate the local cellular microenvironment. These emerging experimental platforms offer exciting opportunities to rapidly identify genetic determinants of disease, to discover modulators of cellular function, and to probe the complex and dynamic relationships between cells and their local environment.

  18. Psychoanalysis and creative living.

    PubMed

    Rubin, Jeffrey B

    2003-01-01

    Psychoanalysis is ambivalent about creativity and its own creative potential. On the one hand, psychoanalysis offers enormous resources for elucidating obstacles to creativity, that way of living, making and relating to self and others that is fresh, vital, unpredictable and open to feedback and evolution. On the other hand, when we analysts know too much beforehand about what a work of art really means or the fundamental and singular motives of creativity, then psychoanalysis unconsciously partakes of a perverse scenario in which the work of art serves as merely a means to the author's ends and is psychologically colonized. When psychoanalysis is The Discipline That Knows, then art has nothing new to teach psychoanalysts and our field is impoverished. "Psychoanalysis and Creative Living" attempts to elucidate how psychoanalysis could work through this tension between its creative and perverse possibilities and foster creative living.

  19. Living My Family's Story

    PubMed Central

    Underhill, Meghan L.; Lally, Robin M.; Kiviniemi, Marc T.; Murekeyisoni, Christine; Dickerson, Suzanne S.

    2013-01-01

    Background Based on known or suggested genetic risk factors, a growing number of women now live with knowledge of a potential cancer diagnosis that may never occur. Given this, it is important to understand the meaning of living with high risk for hereditary breast cancer. Objective The objective of the study was to explore how women at high risk for hereditary breast cancer (1) form self-identity, (2) apply self-care strategies toward risk, and (3) describe the meaning of care through a high-risk breast program. Methods Interpretive hermeneutic phenomenology guided the qualitative research method. Women at high risk for hereditary breast cancer were recruited from a high-risk breast program. Open-ended interview questions focused on experiences living as women managing high risk for breast cancer. Consistent with hermeneutic methodology, the principal investigator led a team to analyze the interview transcripts. Results Twenty women participated in in-depth interviews. Analysis revealed that women describe their own identity based on their family story and grieve over actual and potential familial loss. This experience influences self-care strategies, including seeking care from hereditary breast cancer risk experts for early detection and prevention, as well as maintaining a connection for early treatment “when” diagnosis occurs. Conclusions Healthy women living with high risk for hereditary breast cancer are living within the context of their family cancer story, which influences how they define themselves and engage in self-care. Implications for Practice Findings present important practical, research, and policy information regarding health promotion, psychosocial assessment, and support for women living with this risk. PMID:22544165

  20. Cryopreservation of Living Organs

    NASA Astrophysics Data System (ADS)

    Tanasawa, Ichiro; Nagata, Shinichi; Kimura, Naohiro

    Cryopreservation is considered to be the most promising way of preserving living organs or tissues for a long period of time without casuing any damage to their biological functions. However, cryopreservation has been succeeded only for simple and small-size tissues such as spermatozoon, ovum, erythrocyte, bone marrow and cornea. Cryopreservation of more complex and large-scale organs are not yet succssful. The authors have attempted to establish a technique for cryopreservation of larger living organs. An experiment was carried out using daphnia (water flea). The optimum rates of freezing and thawing were determined together with the optimum selection of cryoprotectant. High recovery rate was achieved under these conditions.

  1. Delayed accumulation of intestinal coliform bacteria enhances life span and stress resistance in Caenorhabditis elegans fed respiratory deficient E. coli

    PubMed Central

    2012-01-01

    Background Studies with the nematode model Caenorhabditis elegans have identified conserved biochemical pathways that act to modulate life span. Life span can also be influenced by the composition of the intestinal microbiome, and C. elegans life span can be dramatically influenced by its diet of Escherichia coli. Although C. elegans is typically fed the standard OP50 strain of E. coli, nematodes fed E. coli strains rendered respiratory deficient, either due to a lack coenzyme Q or the absence of ATP synthase, show significant life span extension. Here we explore the mechanisms accounting for the enhanced nematode life span in response to these diets. Results The intestinal load of E. coli was monitored by determination of worm-associated colony forming units (cfu/worm or coliform counts) as a function of age. The presence of GFP-expressing E. coli in the worm intestine was also monitored by fluorescence microscopy. Worms fed the standard OP50 E. coli strain have high cfu and GFP-labeled bacteria in their guts at the L4 larval stage, and show saturated coliform counts by day five of adulthood. In contrast, nematodes fed diets of respiratory deficient E. coli lacking coenzyme Q lived significantly longer and failed to accumulate bacteria within the lumen at early ages. Animals fed bacteria deficient in complex V showed intermediate coliform numbers and were not quite as long-lived. The results indicate that respiratory deficient Q-less E. coli are effectively degraded in the early adult worm, either at the pharynx or within the intestine, and do not accumulate in the intestinal tract until day ten of adulthood. Conclusions The findings of this study suggest that the nematodes fed the respiratory deficient E. coli diet live longer because the delay in bacterial colonization of the gut subjects the worms to less stress compared to worms fed the OP50 E. coli diet. This work suggests that bacterial respiration can act as a virulence factor, influencing the ability of

  2. Delayed accumulation of intestinal coliform bacteria enhances life span and stress resistance in Caenorhabditis elegans fed respiratory deficient E. coli.

    PubMed

    Gomez, Fernando; Monsalve, Gabriela C; Tse, Vincent; Saiki, Ryoichi; Weng, Emily; Lee, Laura; Srinivasan, Chandra; Frand, Alison R; Clarke, Catherine F

    2012-12-20

    Studies with the nematode model Caenorhabditis elegans have identified conserved biochemical pathways that act to modulate life span. Life span can also be influenced by the composition of the intestinal microbiome, and C. elegans life span can be dramatically influenced by its diet of Escherichia coli. Although C. elegans is typically fed the standard OP50 strain of E. coli, nematodes fed E. coli strains rendered respiratory deficient, either due to a lack coenzyme Q or the absence of ATP synthase, show significant life span extension. Here we explore the mechanisms accounting for the enhanced nematode life span in response to these diets. The intestinal load of E. coli was monitored by determination of worm-associated colony forming units (cfu/worm or coliform counts) as a function of age. The presence of GFP-expressing E. coli in the worm intestine was also monitored by fluorescence microscopy. Worms fed the standard OP50 E. coli strain have high cfu and GFP-labeled bacteria in their guts at the L4 larval stage, and show saturated coliform counts by day five of adulthood. In contrast, nematodes fed diets of respiratory deficient E. coli lacking coenzyme Q lived significantly longer and failed to accumulate bacteria within the lumen at early ages. Animals fed bacteria deficient in complex V showed intermediate coliform numbers and were not quite as long-lived. The results indicate that respiratory deficient Q-less E. coli are effectively degraded in the early adult worm, either at the pharynx or within the intestine, and do not accumulate in the intestinal tract until day ten of adulthood. The findings of this study suggest that the nematodes fed the respiratory deficient E. coli diet live longer because the delay in bacterial colonization of the gut subjects the worms to less stress compared to worms fed the OP50 E. coli diet. This work suggests that bacterial respiration can act as a virulence factor, influencing the ability of bacteria to colonize and

  3. Introduction of Living Polymerization. Living and/or Controlled Polymerization

    DTIC Science & Technology

    1994-06-30

    separated into kinetic and synthetic. The intention of this paper is not to review existing and proclaimed living systems but to discuss the essence of a...o1 OFFICE OF NAVAL RESEARCH S4 CONTRACT N00014-94-1-0101 I R&T Code 31321075 Technical Report No. 10 INTRODUCTION TO LIVING POLYMERIZATION. LIVING ...TITLE AND SUBTITLE S. FUNDING NUMBERS Introduction to Living Polymerization. Living and/or Controlled Polymerization N00014-94-1-0101 6. AUTHOR(S

  4. Design for Living

    ERIC Educational Resources Information Center

    Rosenblum, Todd

    2011-01-01

    Bringing a newborn home from the hospital can come with stress for any parent. Coming home with twins can be double the stress. This article shares the story of a couple faced with this situation 12 years ago with the birth of twins, one was born with complications. They lived in a Colonial until the twins were almost five years old, at which time…

  5. Living with HIV

    MedlinePlus

    ... Abroad Treatment Basic Statistics Get Tested Find an HIV testing site near you. Enter ZIP code or city Follow HIV/AIDS CDC HIV CDC HIV/AIDS See RSS | ... Syndicated Content Website Feedback HIV/AIDS Living With HIV Language: English Spanish Recommend on Facebook Tweet Share ...

  6. Living with Aplastic Anemia

    MedlinePlus

    ... Content: NEXT >> Featured Video Clinical Trials for Rare Blood Diseases (Neal Young, M.D.) 05/17/2012 In ... in the lives of people who have rare blood and bone marrow diseases, such as aplastic anemia. // Non Object? Updated: August ...

  7. Microholography of Living Organisms.

    ERIC Educational Resources Information Center

    Solem, Johndale C.; Baldwin, George C.

    1982-01-01

    By using intense pulsed coherent x-ray sources it will be possible to obtain magnified three-dimensional images of living elementary biological structures at precisely defined instants. Discussed are sources/geometrics for x-ray holography, x-radiation interactions, factors affecting resolution, recording the hologram, high-intensity holography,…

  8. Family Living Supplement.

    ERIC Educational Resources Information Center

    Truitt, Debbie

    This family living supplement contains 125 supplemental ideas and strategies designed to help vocational home economics teachers increase student motivation and enrich the teaching process. Ideas and strategies are organized into seven sections. These are career planning, securing a job, and career success; managing financial resources, buying…

  9. Moab's Living Room

    ERIC Educational Resources Information Center

    Berry, John N., III

    2007-01-01

    This article describes the Grand County Public Library (GCPL) which was awarded the 2007 Best Small Library in America, an award sponsored by "Library Journal" and the Bill & Melinda Gates Foundation. Some 4800 of Grand County, Utah's 8,826 people live in Moab and the rest in the adjacent Spanish Valley and environs. The locals are a…

  10. The Living Periodic Table

    ERIC Educational Resources Information Center

    Nahlik, Mary Schrodt

    2005-01-01

    To help make the abstract world of chemistry more concrete eighth-grade students, the author has them create a living periodic table that can be displayed in the classroom or hallway. This display includes information about the elements arranged in the traditional periodic table format, but also includes visual real-world representations of the…

  11. The Living Periodic Table

    ERIC Educational Resources Information Center

    Nahlik, Mary Schrodt

    2005-01-01

    To help make the abstract world of chemistry more concrete eighth-grade students, the author has them create a living periodic table that can be displayed in the classroom or hallway. This display includes information about the elements arranged in the traditional periodic table format, but also includes visual real-world representations of the…

  12. The living building

    SciTech Connect

    McLennan, J.F.

    1998-07-01

    If one is to increase the energy performance of buildings beyond what is now possible, one can no longer afford to think of a building's systems and components as independent of one another. With emerging trends in building technology, it is becoming possible to design buildings (or groups of buildings) that respond to their environments as naturally as do living organisms. The living building integrates advances in glazing technology, photovoltaics, daylight-integrated lighting controls, HVAC and ecological waste management in conjunction with direct digital controls to respond actively to temperature, humidity, heat gain, cooling, lighting levels, and ventilation. This revolutionary building is the building of the future; it maximizes energy savings due to the inherent efficiency of an intelligent, interconnected system in which the envelope, lighting, and HVAC are always aware of and responding to each other's needs. While some of the technologies for such a system are already in use and resulting energy savings documented, it is not until advances such as electrochromic glazing reach the market that the level of integration necessary to produce the living building will be possible. This paper explores the limits of the living building's capacity to learn from environmental forces and regulate itself; the paper then examines emerging technologies that have demonstrated the potential to make such systemic integration and unprecedented energy savings possible.

  13. Living Systems Energy Module

    SciTech Connect

    1995-09-26

    The Living Systems Energy Module, renamed Voyage from the Sun, is a twenty-lesson curriculum designed to introduce students to the major ways in which energy is important in living systems. Voyage from the Sun tells the story of energy, describing its solar origins, how it is incorporated into living terrestrial systems through photosynthesis, how it flows from plants to herbivorous animals, and from herbivores to carnivores. A significant part of the unit is devoted to examining how humans use energy, and how human impact on natural habitats affects ecosystems. As students proceed through the unit, they read chapters of Voyage from the Sun, a comic book that describes the flow of energy in story form (Appendix A). During the course of the unit, an ``Energy Pyramid`` is erected in the classroom. This three-dimensional structure serves as a classroom exhibit, reminding students daily of the importance of energy and of the fragile nature of our living planet. Interactive activities teach students about adaptations that allow plants and animals to acquire, to use and to conserve energy. A complete list of curricular materials and copies of all activity sheets appear in Appendix B.

  14. Live-cell imaging

    PubMed Central

    Cole, Richard

    2014-01-01

    It would be hard to argue that live-cell imaging has not changed our view of biology. The past 10 years have seen an explosion of interest in imaging cellular processes, down to the molecular level. There are now many advanced techniques being applied to live cell imaging. However, cellular health is often under appreciated. For many researchers, if the cell at the end of the experiment has not gone into apoptosis or is blebbed beyond recognition, than all is well. This is simply incorrect. There are many factors that need to be considered when performing live-cell imaging in order to maintain cellular health such as: imaging modality, media, temperature, humidity, PH, osmolality, and photon dose. The wavelength of illuminating light, and the total photon dose that the cells are exposed to, comprise two of the most important and controllable parameters of live-cell imaging. The lowest photon dose that achieves a measureable metric for the experimental question should be used, not the dose that produces cover photo quality images. This is paramount to ensure that the cellular processes being investigated are in their in vitro state and not shifted to an alternate pathway due to environmental stress. The timing of the mitosis is an ideal canary in the gold mine, in that any stress induced from the imaging will result in the increased length of mitosis, thus providing a control model for the current imagining conditions. PMID:25482523

  15. Learning from Live Theater

    ERIC Educational Resources Information Center

    Greene, Jay P.; Hitt, Collin; Kraybill, Anne; Bogulski, Cari A.

    2015-01-01

    Culturally enriching field trips matter. They produce significant benefits for students on a variety of educational outcomes that schools and communities care about. This experiment on the effects of field trips to see live theater demonstrates that seeing plays is an effective way to teach academic content; increases student tolerance by…

  16. Living with Cystic Fibrosis

    MedlinePlus

    ... page from the NHLBI on Twitter. Living With Cystic Fibrosis If you or your child has cystic fibrosis (CF), you should learn as much as you can ... with your doctors to learn how to manage CF. Ongoing Care Having ongoing medical care by a ...

  17. Learning from Live Theater

    ERIC Educational Resources Information Center

    Greene, Jay P.; Hitt, Collin; Kraybill, Anne; Bogulski, Cari A.

    2015-01-01

    Culturally enriching field trips matter. They produce significant benefits for students on a variety of educational outcomes that schools and communities care about. This experiment on the effects of field trips to see live theater demonstrates that seeing plays is an effective way to teach academic content; increases student tolerance by…

  18. New Lives of Teachers

    ERIC Educational Resources Information Center

    Day, Christopher

    2012-01-01

    The work and lives of teachers have always been subject to external influence as those who are nearing the end of their careers will attest, but it is arguable that what is new over the last two decades is the pace, complexity, and intensity of change as governments have responded to the shrinking world of economic competitiveness and social…

  19. Living or Nonliving?

    ERIC Educational Resources Information Center

    Legaspi, Britt; Straits, William

    2011-01-01

    Categorizing organisms as living or nonliving things may seem to be intuitive by nature. Yet, it is regulated by scientific criteria. Students come to school with rules already in place. Their categorizing criteria have already been influenced by their personal experiences, also known as observations and inferences. They believe that all things…

  20. Living or Nonliving?

    ERIC Educational Resources Information Center

    Legaspi, Britt; Straits, William

    2011-01-01

    Categorizing organisms as living or nonliving things may seem to be intuitive by nature. Yet, it is regulated by scientific criteria. Students come to school with rules already in place. Their categorizing criteria have already been influenced by their personal experiences, also known as observations and inferences. They believe that all things…

  1. Native American Independent Living.

    ERIC Educational Resources Information Center

    Clay, Julie Anna

    1992-01-01

    Examines features of independent living philosophy with regard to compatibility with Native American cultures, including definition or conceptualization of disability; self-advocacy; systems advocacy; peer counseling; and consumer control and involvement. Discusses an actualizing process as one method of resolving cultural conflicts and…

  2. Measuring Retirees' Living Costs.

    ERIC Educational Resources Information Center

    Lamale, Helen H.

    1978-01-01

    The author evaluates the Consumer Price Index (CPI) used by the Bureau of Labor Statistics (BLS) to make cost-of-living adjustments to retirement benefits and considers the need for a separate retiree index. Stating that the CPI has underestimated inflation's impact on retirees, she recommends revised BLS retiree budgets. (MF)

  3. Living the Dream.

    ERIC Educational Resources Information Center

    Rogers, Cynthia; Lemay, Carol

    1991-01-01

    Describes one elementary school's "Living the Dream" award program named in honor of Dr. Martin Luther King, Jr. Students read and reviewed books and presented the award to the author of a recent picture book that focused on multicultural awareness. A list of suggested titles is included. (SM)

  4. You Live, You Learn

    ERIC Educational Resources Information Center

    Biesta, Gert

    2008-01-01

    The Learning Lives project, a four-year study into the learning biographies and trajectories of adults, was conducted by a team of researchers from the universities of Stirling, Exeter, Brighton and Leeds as part of the Teaching and Learning Research Programme (TLRP) of the Economic and Social Research Council, and has just been completed. Whereas…

  5. Design for Living

    ERIC Educational Resources Information Center

    Rosenblum, Todd

    2011-01-01

    Bringing a newborn home from the hospital can come with stress for any parent. Coming home with twins can be double the stress. This article shares the story of a couple faced with this situation 12 years ago with the birth of twins, one was born with complications. They lived in a Colonial until the twins were almost five years old, at which time…

  6. Test Pattern For Living.

    ERIC Educational Resources Information Center

    Johnson, Nicholas

    The lives of Americans today are ruled by interlocking corporations. These corporations together present only one kind of life as viable: the consumer's life. Television is their main means of presenting this view. One cannot choose something he does not know about, and many Americans are not sufficiently informed of the alternatives to make an…

  7. The Living Museum.

    ERIC Educational Resources Information Center

    Merrill, Mary

    1992-01-01

    Presents a lesson plan for a second-grade class project. Suggests that the students will learn to identify the word "famous," complete a timeline for a famous person, learn facts about the person, and express individual thoughts and feelings. Explains the steps involved in the presentation of a living museum where students portray famous…

  8. Construction and characterization of avian Escherichia coli cya crp mutants.

    PubMed

    Peighambari, S M; Gyles, C L

    1998-01-01

    We constructed delta cya delta crp mutants of two avian septicemic Escherichia coli strains and evaluated their attenuation in virulence. The P1 phage was used to transfer cya::Tn10 from an E. coli K-12 strain into virulent avian O78 and O2 E. coli isolates. Tetracycline-resistant transductants were plated on Bochner-Maloy Medium, and tetracycline-sensitive colonies were selected, then tested by polymerase chain reaction to confirm that they had deletions of the cya gene. Deletions of crp were created by the same technique in isolates with deletions in cya. The delta cya and delta cya delta crp derivatives had slower growth rates, smaller colonies, and impaired fermentation of carbohydrates compared with their wild parents, and they did not revert. Attenuation of the mutant strains was evaluated by subcutaneous (s.c.) inoculation of day-old chicks and by intratracheal (i.t.) inoculation of 9-day-old chicks previously inoculated intranasally with infectious bronchitis virus. For the wild O78 strain and its delta cya and delta cya delta crp derivatives, the percentages of chicks that died within 6 days of s.c. injection of approximately 5 x 10(7) organisms were 100, 60, and 0, respectively. The corresponding percentages for wild-type O2 and its delta cya and delta cya delta crp mutants were 100, 70, and 20 at a dose of approximately 2 x 10(5) organisms. Following i.t. inoculation, group scores based on pathologic and bacteriologic findings were 51%, 15%, and 9% for wild, delta cya, and delta crp O78 strains (inoculum approximately 2 x 10(7) organisms) and 98%, 31%, and 11%, respectively, for the corresponding O2 strains (inoculum approximately 4 x 10(6) organisms). This study demonstrated reduced virulence and stability of the double mutant, which may useful as a live attenuated vaccine against poultry colibacillosis.

  9. 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.

  10. 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.

  11. Living related liver transplantation.

    PubMed

    Makuuchi, M; Kawarazaki, H; Iwanaka, T; Kamada, N; Takayama, T; Kumon, M

    1992-01-01

    Liver transplantation from a brain death donor has not yet been accepted in Japan. The only alternative method at present is transplantation from a living donor. After the first successful living related liver transplantation was performed by Strong in Brisbane, Australia, Japanese hepatic and transplant surgeons also began to perform such operations. As of February 1991, 16 living related liver transplantations had already been performed in Japan, mainly for children with biliary atresia. Five of these patients subsequently died, however, our patient has survived more than 1 year, and she is presently leading a normal school life. The most important issue regarding living related liver transplantation is to ensure the donor's safety. For this purpose, we conducted a preoperative banking of the donor's own blood and plasma. In addition, a selective vascular occlusion was carried out to reduce blood loss during the resection of the liver. Intraoperative color Doppler ultrasonography was introduced for evaluating the circulation of the graft. By using this modality, the following three points were able to be accurately estimated in order to obtain optimal graft perfusion: 1) The most suitable position for the graft to be fixed to the abdominal wall, 2) whether or not the abdominal wall could be closed and 3) the indication for a ligation of the collateral veins to form a porto-systemic shunt. Thanks to these procedures, living related liver transplantations have now become an acceptable transplant method, however, a transplantation from a cadaver that is brain dead but still has a beating heart is still absolutely necessary for adult recipients. Therefore, in the future, both methods should be performed.

  12. The evolution of the Escherichia coli phylogeny.

    PubMed

    Chaudhuri, Roy R; Henderson, Ian R

    2012-03-01

    Escherichia coli is familiar to biologists as a classical model system, ubiquitous in molecular biology laboratories around the world. Outside of the laboratory, E. coli strains exist as an almost universal component of the lower-gut flora of humans and animals. Although usually a commensal, E. coli has an alter ego as a pathogen, and is associated with diarrhoeal disease and extra-intestinal infections. The study of E. coli diversity predates the availability of molecular data, with strains initially distinguished by serotyping and metabolic profiling, and genomic diversity illustrated by DNA hybridisation. The quantitative study of E. coli diversity began with the application of multi-locus enzyme electrophoresis (MLEE), and has progressed with the accumulation of nucleotide sequence data, from single genes through multi-locus sequence typing (MLST) to whole genome sequencing. Phylogenetic methods have shed light on the processes of genomic evolution in this extraordinarily diverse species, and revealed the origins of pathogenic E. coli strains, including members of the phylogenetically indistinguishable "genus"Shigella. In May and June 2011, an outbreak of haemorrhagic uraemic syndrome in Germany was linked to a strain of enterohaemorrhagic E. coli (EHEC) O104:H4. Application of high-throughput sequencing technologies allowed the genome and origins of the outbreak strain to be characterised in real time as the outbreak was in progress.

  13. A simple assay to measure phagocytosis of live bacteria.

    PubMed

    Bicker, Heike; Höflich, Conny; Wolk, Kerstin; Vogt, Katrin; Volk, Hans-Dieter; Sabat, Robert

    2008-05-01

    The phagocytosis of pathogens is essential for fighting infections. No assay is available, however, to measure both engulfment and degradation of bacteria under conditions similar to those in vivo. We sought to develop a flow cytometric assay to measure the engulfment and degradation of live bacteria by human blood monocytes and granulocytes. We generated enhanced green fluorescent protein (EGFP)-expressing Eschericha coli by transforming E. coli with the plasmid vector pEGFP. We used these bacteria in a flow cytometric assay to measure both engulfment and degradation of living bacteria by monocytes and granulocytes in human whole blood from fresh, heparinized venous blood samples. To determine whether the test detected differences between healthy individuals and patients with secondary immunodeficiencies, we compared the phagocytosis of monocytes and granulocytes measured in blood samples from immunosuppressed kidney transplantation patients and from patients with postoperative sepsis in immunoparalysis with phagocytosis measured in samples from age-matched healthy individuals. In samples from healthy individuals, we found that in both monocytes and granulocytes bacterial degradation was negatively correlated with the age of the sample donor. Furthermore, we detected decreased bacterial engulfment in granulocytes from septic patients and decreased bacterial degradation in monocytes from immunosuppressed kidney transplantation patients. This flow cytometric assay measures the engulfment and degradation of live bacteria by human blood monocytes and granulocytes. By means of this assay we detected significant differences between healthy controls and patients with secondary immunodeficiencies that may contribute to the increased incidence of infection complications seen in these patients.

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

    SciTech Connect

    Andersson, R.; Schalen, C.; Tranberg, K.G. )

    1991-06-01

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

  15. Genetic analysis of mutagenesis in aging Escherichia coli colonies.

    PubMed

    Taddei, F; Halliday, J A; Matic, I; Radman, M

    1997-10-01

    Bacteria live in unstructured and structured environments, experiencing feast and famine lifestyles. Bacterial colonies can be viewed as model structured environments. SOS induction and mutagenesis have been observed in aging Escherichia coli colonies, in the absence of exogenous sources of DNA damage. This cAMP-dependent mutagenesis occurring in Resting Organisms in a Structured Environment (ROSE) is unaffected by a umuC mutation and therefore differs from both targeted UV mutagenesis and recA730 (SOS constitutive) untargeted mutagenesis. As a recB mutation has only a minor effect on ROSE mutagenesis it also differs from both adaptive reversion of the lacI33 allele and from iSDR (inducible Stable DNA Replication) mutagenesis. Besides its recA and lexA dependence, ROSE mutagenesis is also uvrB and polA dependent. These genetic requirements are reminiscent of the untargeted mutagenesis in lambda phage observed when unirradiated lambda infects UV-irradiated E. coli. These mutations, which are not observed in aging liquid cultures, accumulate linearly with the age of the colonies. ROSE mutagenesis might offer a good model for bacterial mutagenesis in structured environments such as biofilms and for mutagenesis of quiescent eukaryotic cells.

  16. Origins of chemoreceptor curvature sorting in Escherichia coli

    PubMed Central

    Draper, Will; Liphardt, Jan

    2017-01-01

    Bacterial chemoreceptors organize into large clusters at the cell poles. Despite a wealth of structural and biochemical information on the system's components, it is not clear how chemoreceptor clusters are reliably targeted to the cell pole. Here, we quantify the curvature-dependent localization of chemoreceptors in live cells by artificially deforming growing cells of Escherichia coli in curved agar microchambers, and find that chemoreceptor cluster localization is highly sensitive to membrane curvature. Through analysis of multiple mutants, we conclude that curvature sensitivity is intrinsic to chemoreceptor trimers-of-dimers, and results from conformational entropy within the trimer-of-dimers geometry. We use the principles of the conformational entropy model to engineer curvature sensitivity into a series of multi-component synthetic protein complexes. When expressed in E. coli, the synthetic complexes form large polar clusters, and a complex with inverted geometry avoids the cell poles. This demonstrates the successful rational design of both polar and anti-polar clustering, and provides a synthetic platform on which to build new systems. PMID:28322223

  17. DNA-damaging activity of patulin in Escherichia coli.

    PubMed Central

    Lee, K S; Röschenthaler, R J

    1986-01-01

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

  18. Programming a Pavlovian-like conditioning circuit in Escherichia coli

    NASA Astrophysics Data System (ADS)

    Zhang, Haoqian; Lin, Min; Shi, Handuo; Ji, Weiyue; Huang, Longwen; Zhang, Xiaomeng; Shen, Shan; Gao, Rencheng; Wu, Shuke; Tian, Chengzhe; Yang, Zhenglin; Zhang, Guosheng; He, Siheng; Wang, Hao; Saw, Tiffany; Chen, Yiwei; Ouyang, Qi

    2014-01-01

    Synthetic genetic circuits are programmed in living cells to perform predetermined cellular functions. However, designing higher-order genetic circuits for sophisticated cellular activities remains a substantial challenge. Here we program a genetic circuit that executes Pavlovian-like conditioning, an archetypical sequential-logic function, in Escherichia coli. The circuit design is first specified by the subfunctions that are necessary for the single simultaneous conditioning, and is further genetically implemented using four function modules. During this process, quantitative analysis is applied to the optimization of the modules and fine-tuning of the interconnections. Analogous to classical Pavlovian conditioning, the resultant circuit enables the cells to respond to a certain stimulus only after a conditioning process. We show that, although the conditioning is digital in single cells, a dynamically progressive conditioning process emerges at the population level. This circuit, together with its rational design strategy, is a key step towards the implementation of more sophisticated cellular computing.

  19. Evolution and Biophysics of the Escherichia coli lac Operon

    NASA Astrophysics Data System (ADS)

    Ray, J. Christian; Igoshin, Oleg; Quan, Selwyn; Monds, Russell; Cooper, Tim; Balázsi, Gábor

    2011-03-01

    To understand, predict, and control the evolution of living organisms, we consider biophysical effects and molecular network architectures. The lactose utilization system of E. coli is among the most well-studied molecular networks in biology, making it an ideal candidate for such studies. Simulations show how the genetic architecture of the wild-type operon attenuates large metabolic intermediate fluctuations that are predicted to occur in an equivalent system with the component genes on separate operons. Quantification of gene expression in the lac operon evolved in growth conditions containing constant lactose, alternating with glucose, or constant glucose, shows characteristic gene expression patterns depending on conditions. We are simulating these conditions to show context-dependent biophysical sources and costs of different lac operon architectures.

  20. Low level of cross-resistance between triclosan and antibiotics in Escherichia coli K-12 and E. coli O55 compared to E. coli O157.

    PubMed

    Braoudaki, Maria; Hilton, Anthony Craig

    2004-06-15

    Misuse of biocides has encouraged the emergence of resistance and cross-resistance in certain strains. This study investigated resistance of triclosan-adapted Escherichia coli K-12 and E. coli O55 to antimicrobial agents and compared these to E. coli O157:H7. Cross-resistance in E. coli K-12 and E. coli O55 was observed however to a lesser extent than in E. coli O157:H7. Triclosan-adapted E. coli K-12 demonstrated cross-resistance to chloramphenicol, whereas triclosan-adapted E. coli O55 exhibited resistance to trimethoprim. In comparison, E. coli O157:H7 was resistant to chloramphenicol, tetracycline, amoxicillin, amoxicillin/clavulanic acid, trimethoprim, benzalkonium chloride and chlorohexidine suggesting strain specific rather than general resistance mechanisms.

  1. Survival of pathogenic Escherichia coli on basil, lettuce, and spinach

    USDA-ARS?s Scientific Manuscript database

    The contamination of lettuce, spinach and basil with pathogenic E. coli has caused numerous illnesses over the past decade. E. coli O157:H7, E. coli O104:H4 and avian pathogenic E. coli (APECstx- and APECstx+) were inoculated on basil plants and in promix soiless substrate using drip and overhead ir...

  2. Advances in genoserotyping and subtyping of Escherichia coli

    USDA-ARS?s Scientific Manuscript database

    E. coli plays an important role as a member of the gut microbiota; however, pathogenic strains also exist, including various diarrheagenic E. coli pathotypes and extraintestinal pathogenic E. coli that cause illness outside of the GI-tract. E. coli have traditionally been serotyped using antisera a...

  3. 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... coli serological reagents. (a) Identification. Escherichia coli serological reagents are devices that consist of antigens and antisera used in serological tests to identify Escherichia coli from cultured...

  4. A de novo protein confers copper resistance in Escherichia coli.

    PubMed

    Hoegler, Kenric J; Hecht, Michael H

    2016-07-01

    To survive environmental challenges, biological systems rely on proteins that were selected by evolution to function in particular cellular and conditional settings. With the advent of protein design and synthetic biology, it is now possible to construct novel proteins that are not biased by eons of selection in natural hosts. The availability of these sequences prompts us to ask whether natural biological organisms can use naïve-non-biological-proteins to enhance fitness in stressful environments. To address this question, we transformed a library of DNA sequences encoding ∼1.5 × 10(6) binary patterned de novo proteins into E. coli, and selected for sequences that enable growth in concentrations of copper that would otherwise be toxic. Several novel sequences were discovered, and one of them, called Construct K (ConK), was studied in detail. Cells expressing ConK accumulate approximately 50% less copper than control cells. The function of ConK does not involve an oxidase, nor does it require two of the best characterized copper efflux systems. However, the ability of ConK to rescue cells from toxic concentrations of copper does require an active proton motive force. Further selections for growth in higher concentrations of copper led to the laboratory evolution of variants of ConK with enhanced levels of activity in vivo. These studies demonstrate that novel proteins, unbiased by evolutionary history in the natural world, can enhance the fitness of biological systems. Living systems evolve to adapt to potentially lethal environmental changes. This normally involves repurposing existing genetic information (i.e. sequences that were selected by billions of years of evolution). Here we show that a completely de novo protein, not derived from nature, can enable E. coli cells to grow in otherwise toxic concentrations of copper, demonstrating that living systems also have the capacity to incorporate and protopurpose entirely novel genetic information. © 2016 The

  5. Influence of chicken serum mannose-binding lectin levels on the immune response towards Escherichia coli.

    PubMed

    Norup, L R; Dalgaard, T S; Friggens, N C; Sørensen, P; Juul-Madsen, H R

    2009-03-01

    This study aimed to investigate the effect of mannose-binding lectin (MBL) on infections with Escherichia coli in chickens. Initially, the basic levels of MBL in 4 different lines of layer chickens, namely ISA Brown, Lohmann Selected Leghorn, Lohmann Braun, and Hellevad, were investigated. This investigation revealed a 2-to 3-fold difference in the basic levels of MBL in serum between some of these commercial lines. Furthermore, the ontogeny of the basic level of MBL in serum of an experimental chicken line was investigated. The level of MBL was very stabile for long periods, with an elevation at 5 to 7 wk of age. Another elevation in MBL level started around 18 to 19 wk of age and stayed elevated at least until 38 wk of age. In this study, it was hypothesized that chickens with high levels of MBL (H-type) may be less prone to disease caused by E. coli infection than chickens with low levels of MBL (L-type) after attempts were made to immunosuppress the chickens by immunization with a live attenuated infectious bursal disease virus (IBDV) vaccine strain. The H-type and L-type chickens were divided into 4 groups receiving either no treatment (I-E-), E. coli alone (I-E+), IBDV alone (I+E-), or IBDV and E. coli (I+E+). Body weight gain was depressed by IBDV immunization as well as E. coli inoculation. The depression of BW gain was significantly larger in L-type chickens compared with H-type chickens. The antibody response to E. coli was significantly depressed by IBDV vaccination and antibody titers to E. coli were elevated by experimental E. coli inoculation, but only in the group not given IBDV (I-E- vs. I-E+). On d 28, T-cell responses in L-type chickens showed a lower percentage of proliferating CD4+ and CD8+ T cells compared with the H-type, regardless of treatment. In conclusion, immune reactions toward infections with E. coli differed between chickens having different basal serum MBL levels, and as such, MBL may be of importance for future selection of more

  6. Watersheds: where we live

    USGS Publications Warehouse

    Vandas, Stephen; Farrar, Frank

    1996-01-01

    We all live in a watershed. Animals and plants all live there with us. Everyone affects what happens in a watershed by how we treat the natural resources. So what is a watershed? It is the land area that drains water to a stream, river, lake, or ocean. Water travels over the Earth's surface across forest land, farm fields, pastures, suburban lawns, and city streets, or it seeps into the soil and makes its way to a stream as local ground water. Watersheds come in many different shapes and sizes. Some contain mountains and hills, and others are nearly flat. A watershed can be affected by many different activities and events. Construction of cities and towns, farming, logging, and the application and disposal of many garden and household chemicals can affect the quantity and quality of water flowing from a watershed.

  7. Prevalence of CTX-M-Type extended-spectrum β-lactamases in Escherichia coli strains isolated in poultry farms.

    PubMed

    Abreu, Rossana; Castro, Beatriz; Espigares, Elena; Rodríguez-Álvarez, Cristobalina; Lecuona, María; Moreno, Elena; Espigares, Miguel; Arias, Angeles

    2014-11-01

    The aim of the study was to detect the prevalence of CTX-M-type extended-spectrum β-lactamases (ESBL) in Escherichia coli strains isolated in healthy chickens at poultry farms in Tenerife, Spain. From November 2012 to February 2013, 260 live chickens were screened. Samples were cultured in chromogenic media. Suspect strains were identified by Vitek 2 system and ESBL production was confirmed by the double-disk synergy test. Pulsed-field gel electrophoresis (PFGE) was performed with XbaI (Promega, Madison, WI) to ESBL-E. coli isolates. The presence of CTX-M-type was detected by real-time polymerase chain reaction. Of 260 rectal swabs, 237 (91.1%) were ESBL-E. coli, 196 (75.38%) strains were characterized by PFGE, and CTX-M-type was detected in 116 (59.1%) of these strains. With respect to the susceptibility patterns of E. coli blaCTX-M strains, 7.8% showed resistance to more than two non-β-lactam antibiotics. In our area, the prevalence of CTX-M-type in E. coli isolated in chicken was even higher than those found in other countries. The impact of food animals as a possible reservoir for ESBL-E. coli, especially CTX-M-type ESBL, and the dissemination of such strains into the food production chain need to be assessed.

  8. Electrophoretic Mobilities of Escherichia coli O157:H7 and Wild-Type Escherichia coli Strains

    PubMed Central

    Lytle, Darren A.; Rice, Eugene W.; Johnson, Clifford H.; Fox, Kim R.

    1999-01-01

    The electrophoretic mobilities (EPMs) of a number of Escherichia coli O157:H7 and wild-type E. coli strains were measured. The effects of pH and ionic strength on the EPMs were investigated. The EPMs of E. coli O157:H7 strains differed from those of wild-type strains. As the suspension pH decreased, the EPMs of both types of strains increased. PMID:10388724

  9. Protective effects of indigenous Escherichia coli against a pathogenic E. coli challenge strain in pigs.

    PubMed

    Vahjen, W; Cuisiniere, T; Zentek, J

    2017-10-03

    To investigate the inhibitory effect of indigenous enterobacteria on pathogenic Escherichia coli, a challenge trial with postweaning pigs was conducted. A pathogenic E. coli strain was administered to all animals and their health was closely monitored thereafter. Faecal samples were taken from three healthy and three diarrhoeic animals. Samples were cultivated on MacConkey agar and isolates were subcultured. A soft agar overlay assay was used to determine the inhibitory activity of the isolates. A total of 1,173 enterobacterial isolates were screened for their ability to inhibit the E. coli challenge strain. Colony forming units of enterobacteria on MacConkey agar were not different between healthy and diarrhoeic animals in the original samples. Furthermore, numbers of isolates per animal were also not significantly different between healthy (482 isolates) and diarrhoeic animals (691 isolates). A total of 43 isolates (3.7%) with inhibitory activity against the pathogenic E. coli challenge strain were detected. All inhibitory isolates were identified as E. coli via MALDI-TOF. The isolates belonged to the phylotypes A, C and E. Many isolates (67.4%) were commensal E. coli without relevant porcine pathogenic factors, but toxin- and fimbrial genes (stx2e, fae, estIb, elt1a, fas, fan) were detected in 14 inhibitory isolates. Healthy animals showed significantly (P=0.003) more inhibitory isolates (36 of 482 isolates; 7.5%) than diseased animals (7 of 691 isolates; 1.0%). There were no significant correlations regarding phylotype or pathogenic factors between healthy and diseased animals. This study has shown that a small proportion of indigenous E. coli is able to inhibit in vitro growth of a pathogenic E. coli strain in pigs. Furthermore, healthy animals possess significantly more inhibitory E. coli strains than diarrhoeic animals. The inhibition of pathogenic E. coli by specific indigenous E. coli strains may be an underlying principle for the containment of pathogenic

  10. Improving assisted living care.

    PubMed

    Gregory, Nancy; Gesell, Sabina B; Widmer, Tom

    2007-01-01

    In the absence of a national measurement system, private vendors of satisfaction measurement and improvement services have played a crucial role in the quality movement in the assisted living industry. Survey responses from 175 resident-family dyads at 20 facilities were analyzed to identify priorities for service improvement from the customers' perspective. They include improving care provided by aides and management, meal service, and activities. Practical solutions for addressing these issues are presented.

  11. Biofuels from E. Coli: Engineering E. coli as an Electrofuels Chassis for Isooctane Production

    SciTech Connect

    2010-07-16

    Electrofuels Project: Ginkgo Bioworks is bypassing photosynthesis and engineering E. coli to directly use carbon dioxide (CO2) to produce biofuels. E. coli doesn’t naturally metabolize CO2, but Ginkgo Bioworks is manipulating and incorporating the genes responsible for CO2 metabolism into the microorganism. By genetically modifying E. coli, Ginkgo Bioworks will enhance its rate of CO2 consumption and liquid fuel production. Ginkgo Bioworks is delivering CO2 to E. coli as formic acid, a simple industrial chemical that provides energy and CO2 to the bacterial system.

  12. First international E. coli genome meeting

    SciTech Connect

    Not Available

    1992-12-31

    This volume is a collection of abstracts of oral presentations and poster sessions of studies reported at the First International E. Coli Genome Meeting, held September 10-14, 1992 at the University of Wisconsin.

  13. First international E. coli genome meeting

    SciTech Connect

    Not Available

    1992-01-01

    This volume is a collection of abstracts of oral presentations and poster sessions of studies reported at the First International E. Coli Genome Meeting, held September 10-14, 1992 at the University of Wisconsin.

  14. Structure of Water in Escherichia Coli B

    DTIC Science & Technology

    structure broadening of the NMR water spectrum. Using bacteria grown in the special chemically defined medium, we showed that the water in E. coli B was highly ordered and was very different from ’free’ water and from polywater .

  15. Native valve Escherichia coli endocarditis following urosepsis.

    PubMed

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

    2013-05-01

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

  16. Interior view of former living porch, now living area extension, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Interior view of former living porch, now living area extension, facing east. - Albrook Air Force Station, Field Officer's Quarters, West side of Dargue Avenue Circle, Balboa, Former Panama Canal Zone, CZ

  17. Living Room Mantel Profile, Door Jamb, Window Sill, Baseboard, Living ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Living Room Mantel Profile, Door Jamb, Window Sill, Baseboard, Living Room Fireplace Details, Door Profile - National Home for Disabled Volunteer Soldiers - Battle Mountain Sanitarium, Governor's Quarters, 500 North Fifth Street, Hot Springs, Fall River County, SD

  18. Interior view of living area and living porch showing structural ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Interior view of living area and living porch showing structural system, facing north. - Albrook Air Force Station, Company Officer's Quarters, East side of Canfield Avenue, Balboa, Former Panama Canal Zone, CZ

  19. Systems Metabolic Engineering of Escherichia coli.

    PubMed

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

    2017-03-01

    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.

  20. 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.

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

    PubMed Central

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

    2014-01-01

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

  2. 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

  3. Cation Transport in Escherichia coli

    PubMed Central

    Schultz, Stanley G.; Solomon, A. K.

    1961-01-01

    Methods have been developed to study the intracellular Na and K concentrations in E. coli, strain K-12. These intracellular cation concentrations have been shown to be functions of the extracellular cation concentrations and the age of the bacterial culture. During the early logarithmic phase of growth, the intracellular K concentration greatly exceeds that of the external medium, whereas the intracellular Na concentration is lower than that of the growth medium. As the age of the culture increases, the intracellular K concentration falls and the intracellular Na concentration rises, changes which are related to the fall in the pH of the medium and to the accumulation of the products of bacterial metabolism. When stationary phase cells, which are rich in Na and poor in K, are resuspended in fresh growth medium, there is a rapid reaccumulation of K and extrusion of Na. These processes represent oppositely directed net ion movements against concentration gradients, and have been shown to be dependent upon the presence of an intact metabolic energy supply. PMID:13909521

  4. Cation Transport in Escherichia coli

    PubMed Central

    Schultz, Stanley G.; Epstein, Wolfgang; Solomon, A. K.

    1963-01-01

    The resuspension of K-poor, Na-rich stationary phase E. coli in fresh medium at pH 7.0 results in a rapid uptake of K and extrusion of Na by the cells. In all experiments net K uptake exceeded net Na extrusion. An investigation of the uptake of glucose, PO4, and Mg and the secretion of H by these cells indicates that the excess K uptake is not balanced by the simultaneous uptake of anions but must be accompanied by the extrusion of cations from the cell. The kinetics of net K uptake are consistent with the existence of two parallel influx processes. The first is rapid, of brief duration, and accounts for approximately 60 per cent of the total net K uptake. This process is a function of the extracellular K concentration, is inhibited in acid media, and appears to be a 1 for 1 exchange of extracellular K for intracellular H. The second influx process has a half-time of approximately 12 minutes, and is not affected by acid media. This process is a function of the intracellular Na concentration, is dependent upon the presence of K in the medium, and may be ascribed to a 1 for 1 exchange of extracellular K for intracellular Na. PMID:14080819

  5. Evidence of class 1 integron transfer between Escherichia coli and Salmonella spp. on livestock farms.

    PubMed

    Mathew, Alan G; Liamthong, Sumalee; Lin, Jun; Hong, Yingying

    2009-10-01

    A study was conducted to determine if homologous integrons occurred in Escherichia coli and Salmonella spp. within livestock production sites in the United States and Thailand suggesting transfer of genetic resistance elements between those organisms. Fecal samples were collected via rectal swabs from live swine in the United States and Thailand, and cloacal swabs from live chickens in Thailand, and killed chickens at a U.S. abattoir. Isolates were derived only from farms harboring both Salmonella and E. coli, resulting in the inclusion of 571 E. coli and 98 Salmonella isolates derived from both livestock species in the United States and Thailand. Class 1 integron variable regions were detected using polymerase chain reaction targeting 5' and 3' conserved sequences. When integron-positive E. coli and Salmonella from the same farm had identical amplicon patterns, polymerase chain reaction products were sequenced to determine homology. Nine integron amplicons, with sizes ranging from 0.5 to 2.5 kb, were observed in bacterial isolates, and we found a single swine farm in Thailand from which identical amplicons were observed in both E. coli and Salmonella. Sequence analysis revealed a 1.0 kb amplicon common to both bacteria contained an aadA1 gene cassette encoding aminoglycoside 3'-adenyltransferase, conferring resistance to streptomycin and spectinomycin. A 2.0 kb amplicon was also found in both types of bacteria from that farm, containing an aadA5 gene encoding aminoglycoside 3'-adenyltransferase, an additional reading frame, orfD, with unknown function, and a dfrA17 gene encoding dihydrofolate reductase, conferring resistance to trimethoprim. Further analyses determined the amplicons were contained on plasmid DNA in both E. coli and Salmonella, and a plasmid of similar size was identified in both species and was found to harbor the class 1 integron. Our results indicate that while in most cases, integrons of coexisting E. coli and Salmonella differed, identical

  6. Live from the Arctic

    NASA Astrophysics Data System (ADS)

    Haines-Stiles, G.; Warnick, W. K.; Warburton, J.; Sunwood, K.

    2003-12-01

    For reasons of geography and geophysics, the poles of our planet, the Arctic and Antarctica, are places where climate change appears first: they are global canaries in the mine shaft. But while Antarctica (its penguins and ozone hole, for example) has been relatively well-documented in recent books, TV programs and journalism, the far North has received somewhat less attention. This project builds on and advances what has been done to date to share the people, places, and stories of the North with all Americans through multiple media, over several years. In a collaborative project between the Arctic Research Consortium of the United States (ARCUS) and PASSPORT TO KNOWLEDGE, Live from the Arctic will bring the Arctic environment to the public through a series of primetime broadcasts, live and taped programming, interactive virtual field trips, and webcasts. The five-year project will culminate during the 2007-2008 International Polar Year (IPY). Live from the Arctic will: A. Promote global understanding about the value and world -wide significance of the Arctic, B. Bring cutting-edge research to both non-formal and formal education communities, C. Provide opportunities for collaboration between arctic scientists, arctic communities, and the general public. Content will focus on the following four themes. 1. Pan-Arctic Changes and Impacts on Land (i.e. snow cover; permafrost; glaciers; hydrology; species composition, distribution, and abundance; subsistence harvesting) 2. Pan-Arctic Changes and Impacts in the Sea (i.e. salinity, temperature, currents, nutrients, sea ice, marine ecosystems (including people, marine mammals and fisheries) 3. Pan-Arctic Changes and Impacts in the Atmosphere (i.e. precipitation and evaporation; effects on humans and their communities) 4. Global Perspectives (i.e. effects on humans and communities, impacts to rest of the world) In The Earth is Faster Now, a recent collection of comments by members of indigenous arctic peoples, arctic

  7. Live from the Arctic

    NASA Astrophysics Data System (ADS)

    Warnick, W. K.; Haines-Stiles, G.; Warburton, J.; Sunwood, K.

    2003-12-01

    For reasons of geography and geophysics, the poles of our planet, the Arctic and Antarctica, are places where climate change appears first: they are global canaries in the mine shaft. But while Antarctica (its penguins and ozone hole, for example) has been relatively well-documented in recent books, TV programs and journalism, the far North has received somewhat less attention. This project builds on and advances what has been done to date to share the people, places, and stories of the North with all Americans through multiple media, over several years. In a collaborative project between the Arctic Research Consortium of the United States (ARCUS) and PASSPORT TO KNOWLEDGE, Live from the Arctic will bring the Arctic environment to the public through a series of primetime broadcasts, live and taped programming, interactive virtual field trips, and webcasts. The five-year project will culminate during the 2007-2008 International Polar Year (IPY). Live from the Arctic will: A. Promote global understanding about the value and world -wide significance of the Arctic, B. Bring cutting-edge research to both non-formal and formal education communities, C. Provide opportunities for collaboration between arctic scientists, arctic communities, and the general public. Content will focus on the following four themes. 1. Pan-Arctic Changes and Impacts on Land (i.e. snow cover; permafrost; glaciers; hydrology; species composition, distribution, and abundance; subsistence harvesting) 2. Pan-Arctic Changes and Impacts in the Sea (i.e. salinity, temperature, currents, nutrients, sea ice, marine ecosystems (including people, marine mammals and fisheries) 3. Pan-Arctic Changes and Impacts in the Atmosphere (i.e. precipitation and evaporation; effects on humans and their communities) 4. Global Perspectives (i.e. effects on humans and communities, impacts to rest of the world) In The Earth is Faster Now, a recent collection of comments by members of indigenous arctic peoples, arctic

  8. Valuing different human lives.

    PubMed

    Goodwin, Geoffrey P; Landy, Justin F

    2014-04-01

    Do people think of the value of all human lives as equivalent irrespective of age? Affirmations of the equal value of all human lives are culturally prominent, yet much evidence points to the fact that the young are often prioritized over the old in life-and-death decision-making contexts. Studies 1-3 aimed to reconcile this tension by showing that although individuals are seen as more equal with respect to negative rights not to be harmed or killed (though not completely equal), they are seen as less equal with respect to positive rights to be aided or saved. Age exerts a large and systematic impact on decisions about who to save and about whose death is more tragic, suggesting that individuals are seen as possessing differing amounts of contingent value. These initial studies also yielded the novel finding that, although children are prioritized over adults, older children are often prioritized over younger children. Study 4 replicated this finding with a think-aloud methodology; the study showed that the preference for older children appears to be driven by their having had more invested in their lives, their better developed social relations, and their greater understanding of death. Studies 5a-5c demonstrated the independent causal effects of each of these variables on judgments of life's value. Finally, in Studies 6 and 7, mediation methods were used to show that older children's more meaningful social relations primarily explain the greater value of older than of younger children. These findings have implications for bioethics and medical policy.

  9. Microencapsulation Of Living Cells

    NASA Technical Reports Server (NTRS)

    Chang, Manchium; Kendall, James M.; Wang, Taylor G.

    1989-01-01

    In experimental technique, living cells and other biological materials encapsulated within submillimeter-diameter liquid-filled spheres. Sphere material biocompatible, tough, and compliant. Semipermeable, permitting relatively small molecules to move into and out of sphere core but preventing passage of large molecules. New technique promises to make such spherical capsules at high rates and in uniform, controllable sizes. Capsules injected into patient through ordinary hypodermic needle. Promising application for technique in treatment of diabetes. Also used to encapsulate pituitary cells and thyroid hormone adrenocortical cells for treatment of other hormonal disorders, to encapsulate other secreting cells for transplantation, and to package variety of pharmaceutical products and agricultural chemicals for controlled release.

  10. Living in Space

    NASA Technical Reports Server (NTRS)

    Brown, Ray (Editor)

    1993-01-01

    In this educational video from the 'Liftoff to Learning' series, astronauts from the STS-56 Mission (Ken Cockrell, Mike Foale, Ellen Ochoa, Steve Oswald, and Ken Cameron) explain and show through demonstrations how microgravity affects the way astronauts live onboard the Space Shuttle, and how these same daily habits or processes differ on Earth. A tour of the Space Shuttle is given, including the sleeping compartments, the kitchen area, the storage compartments, and the Waste Collection System (or WCS, as they call it). Daily habits (brushing teeth, shampooing hair and bathing, eating,...) are explained and actively illustrated, along with reasons of how these applications differ from their employment on Earth.

  11. Living olefin polymerization processes

    DOEpatents

    Schrock, R.R.; Baumann, R.

    1999-03-30

    Processes for the living polymerization of olefin monomers with terminal carbon-carbon double bonds are disclosed. The processes employ initiators that include a metal atom and a ligand having two group 15 atoms and a group 16 atom or three group 15 atoms. The ligand is bonded to the metal atom through two anionic or covalent bonds and a dative bond. The initiators are particularly stable under reaction conditions in the absence of olefin monomer. The processes provide polymers having low polydispersities, especially block copolymers having low polydispersities. It is an additional advantage of these processes that, during block copolymer synthesis, a relatively small amount of homopolymer is formed.

  12. Living olefin polymerization processes

    DOEpatents

    Schrock, Richard R.; Baumann, Robert

    1999-01-01

    Processes for the living polymerization of olefin monomers with terminal carbon-carbon double bonds are disclosed. The processes employ initiators that include a metal atom and a ligand having two group 15 atoms and a group 16 atom or three group 15 atoms. The ligand is bonded to the metal atom through two anionic or covalent bonds and a dative bond. The initiators are particularly stable under reaction conditions in the absence of olefin monomer. The processes provide polymers having low polydispersities, especially block copolymers having low polydispersities. It is an additional advantage of these processes that, during block copolymer synthesis, a relatively small amount of homopolymer is formed.

  13. Living olefin polymerization processes

    DOEpatents

    Schrock, Richard R.; Baumann, Robert

    2003-08-26

    Processes for the living polymerization of olefin monomers with terminal carbon-carbon double bonds are disclosed. The processes employ initiators that include a metal atom and a ligand having two group 15 atoms and a group 16 atom or three group 15 atoms. The ligand is bonded to the metal atom through two anionic or covalent bonds and a dative bond. The initiators are particularly stable under reaction conditions in the absence of olefin monomer. The processes provide polymers having low polydispersities, especially block copolymers having low polydispersities. It is an additional advantage of these processes that, during block copolymer synthesis, a relatively small amount of homopolymer is formed.

  14. Living olefin polymerization processes

    DOEpatents

    Schrock, Richard R.; Bauman, Robert

    2006-11-14

    Processes for the living polymerization of olefin monomers with terminal carbon-carbon double bonds are disclosed. The processes employ initiators that include a metal atom and a ligand having two group 15 atoms and a group 16 atom or three group 15 atoms. The ligand is bonded to the metal atom through two anionic or covalent bonds and a dative bond. The initiators are particularly stable under reaction conditions in the absence of olefin monomer. The processes provide polymers having low polydispersities, especially block copolymers having low polydispersities. It is an additional advantage of these processes that, during block copolymer synthesis, a relatively small amount of homopolymer is formed.

  15. Living in Space

    NASA Technical Reports Server (NTRS)

    Brown, Ray (Editor)

    1993-01-01

    In this educational video from the 'Liftoff to Learning' series, astronauts from the STS-56 Mission (Ken Cockrell, Mike Foale, Ellen Ochoa, Steve Oswald, and Ken Cameron) explain and show through demonstrations how microgravity affects the way astronauts live onboard the Space Shuttle, and how these same daily habits or processes differ on Earth. A tour of the Space Shuttle is given, including the sleeping compartments, the kitchen area, the storage compartments, and the Waste Collection System (or WCS, as they call it). Daily habits (brushing teeth, shampooing hair and bathing, eating,...) are explained and actively illustrated, along with reasons of how these applications differ from their employment on Earth.

  16. "Living versus Dead":

    PubMed Central

    Chakrabarti, Pratik

    2010-01-01

    Summary The Semple antirabies vaccine was developed by David Semple in India in 1911. Semple introduced a peculiarly British approach within the Pasteurian tradition by using carbolized dead virus. This article studies this unique phase of vaccine research between 1910 and 1935 to show that in the debates and laboratory experiments around the potency and safety of vaccines, categories like "living" and "dead" were often used as ideological and moral denominations. These abstract and ideological debates were crucial in defining the final configuration of the Semple vaccine, the most popular antirabies vaccine used globally, and also in shaping international vaccination policies. PMID:21037397

  17. Communication in Assisted Living*

    PubMed Central

    Williams, Kristine N.; Warren, Carol A.B.

    2009-01-01

    This study of communication in an Assisted Living Facility (ALF) focuses on staff’s interpretive frameworks and situational tactics for managing elderly residents. It is based on interviews with staff and residents in an ALF together with ethnographic fieldwork. As in other quasi-total institutions, staff members engage in control as well as care, monitoring residents for compliance with rules and directives. Residents, aware of the threat of being moved to a nursing home, also monitor their own behavior and cognition in comparison to other residents. Other communication issues include the infantilization of the elderly by staff, and the race, class, and ethnic prejudices of residents. PMID:20107612

  18. Living with a Single Parent

    MedlinePlus

    ... Video: Getting an X-ray Living With a Single Parent KidsHealth > For Kids > Living With a Single Parent ... single parents can be a great idea, too. Single Parents and Work Single parents are often working parents ...

  19. Living with a Single Parent

    MedlinePlus

    ... Happens in the Operating Room? Living With a Single Parent KidsHealth > For Kids > Living With a Single Parent ... single parents can be a great idea, too. Single Parents and Work Single parents are often working parents ...

  20. Living with Sickle Cell Disease

    MedlinePlus

    ... from the NHLBI on Twitter. Living With Sickle Cell Disease If you or your child has sickle ... NEXT >> Featured Video Living With and Managing Sickle Cell Disease (Nicholas) 09/02/2011 In this video— ...

  1. A Transcriptional “Scream” Early Response of E. coli Prey to Predatory Invasion by Bdellovibrio

    PubMed Central

    Lambert, Carey; Ivanov, Pavel

    2009-01-01

    We have transcriptionally profiled the genes differentially expressed in E. coli prey cells when predatorily attacked by Bdellovibrio bacteriovorus just prior to prey cell killing. This is a brief, approximately 20–25 min period when the prey cell is still alive but contains a Bdellovibrio cell in its periplasm or attached to and penetrating its outer membrane. Total RNA was harvested and labelled 15 min after initiating a semi-synchronous infection with an excess of Bdellovibrio preying upon E. coli and hybridised to a macroarray spotted with all predicted ORFs of E. coli. SAM analysis and t-tests were performed on the resulting data and 126 E. coli genes were found to be significantly differentially regulated by the prey upon attack by Bdellovibrio. The results were confirmed by QRT-PCR. Amongst the prey genes upregulated were a variety of general stress response genes, potentially “selfish” genes within or near prophages and transposable elements, and genes responding to damage in the periplasm and osmotic stress. Essentially, the presence of the invading Bdellovibrio and the resulting damage to the prey cell elicited a small “transcriptional scream”, but seemingly no specific defensive mechanism with which to counter the Bdellovibrio attack. This supports other studies which do not find Bdellovibrio resistance responses in prey, and bodes well for its use as a “living antibiotic”. PMID:20024656

  2. A transcriptional "Scream" early response of E. coli prey to predatory invasion by Bdellovibrio.

    PubMed

    Lambert, Carey; Ivanov, Pavel; Sockett, Renee Elizabeth

    2010-06-01

    We have transcriptionally profiled the genes differentially expressed in E. coli prey cells when predatorily attacked by Bdellovibrio bacteriovorus just prior to prey cell killing. This is a brief, approximately 20-25 min period when the prey cell is still alive but contains a Bdellovibrio cell in its periplasm or attached to and penetrating its outer membrane. Total RNA was harvested and labelled 15 min after initiating a semi-synchronous infection with an excess of Bdellovibrio preying upon E. coli and hybridised to a macroarray spotted with all predicted ORFs of E. coli. SAM analysis and t-tests were performed on the resulting data and 126 E. coli genes were found to be significantly differentially regulated by the prey upon attack by Bdellovibrio. The results were confirmed by QRT-PCR. Amongst the prey genes upregulated were a variety of general stress response genes, potentially "selfish" genes within or near prophages and transposable elements, and genes responding to damage in the periplasm and osmotic stress. Essentially, the presence of the invading Bdellovibrio and the resulting damage to the prey cell elicited a small "transcriptional scream", but seemingly no specific defensive mechanism with which to counter the Bdellovibrio attack. This supports other studies which do not find Bdellovibrio resistance responses in prey, and bodes well for its use as a "living antibiotic".

  3. The effect of single-walled carbon nanotubes on Escherichia coli: multiple indicators of viability

    NASA Astrophysics Data System (ADS)

    Le, Tu Thi Anh; McEvoy, John; Khan, Eakalak

    2015-01-01

    The impact of single-walled carbon nanotubes (SWCNTs) on Escherichia coli ATCC 8739 was investigated using four indicators of viability: enzyme activity, membrane integrity, plate count, and total RNA. The study examined the effects of SWCNT concentration (5, 10, 20, 50, 100, 200, 500, and 1,000 μg/ml), SWCNT length (0.5-2 and 5-30 μm), and bacterial density (6.5 log10 CFU and 9 log10 CFU per treatment) on E. coli ATCC 8739 viability. Results show that anti-bacterial activity is dependent on both the length and concentration of SWCNTs. Long SWCNTs (5-30 µm) were more toxic for E. coli than short SWCNTs (0.5-2 µm). The susceptibility of E. coli to SWCNTs was dependent on the initial density of cells in the treatment, with cells at the higher density being more resistant. Estimates of viability reductions were generally similar for the four assays examined; however, the beta galactosidase and LIVE/DEAD assays were more conservative than the plate count as indicators of viability reductions.

  4. [Epidemiological characteristics of diarrheagenic Escherichia coli among diarrhea outpatients in China, 2012-2015].

    PubMed

    Zhang, Z K; Lai, S J; Yu, J X; Yang, W Q; Wang, X; Jing, H Q; Li, Z J; Yang, W Z

    2017-04-10

    Objective: To understand the epidemiological characteristics of diarrheagenic Escherichia (E.) coli (DEC) among diarrhea outpatients in China. Methods: Diarrhea surveillance program was conducted in outpatient and emergency departments from 170 hospitals that under the sentinel programs in 27 provinces, from 2012-2015. Clinical and epidemiological data regarding diarrhea patients were collected, with fecal specimens sampled and tested for DEC in 92 network-connected laboratories. Results: Among all the 46 721 diarrhea cases, 7.7% of them appeared DEC positive in those with geographic heterogeneity. In 2 982 cases (6.4%) with available data on PCR subtypes of DEC, enteroaggregative E. coli (EAEC, 1 205 cases, 40.4%) appeared the most commonly seen pathogens, followed by enteropathogenic E. coli (EPEC, 815 cases, 27.3%), and enterotoxigenic E.coli (ETEC, 653 cases, 21.9%). The highest positive rate of DEC was observed in outpatients of 25-34 years old (10.1%), living in the warm temperate zones (11.1%), and with mucous-like stool (9.4%). The positive rate of DEC showed a strong seasonal pattern, with peaks in summer, for all the subtypes. Conclusions: DEC seemed easy to be detected among diarrhea outpatients in China, with EAEC, EPEC and ETEC the most commonly identified subtypes. Epidemiological characteristics regarding the heterogeneities of DEC appeared different, in regions, age groups and seasons. Long-term surveillance programs should be strengthened to better understand the epidemiology of DEC, in China.

  5. Pathogenic Escherichia coli strain discrimination using laser-induced breakdown spectroscopy

    NASA Astrophysics Data System (ADS)

    Diedrich, Jonathan; Rehse, Steven J.; Palchaudhuri, Sunil

    2007-07-01

    A pathogenic strain of bacteria, Escherichia coli O157:H7 (enterohemorrhagic E. coli or EHEC), has been analyzed by laser-induced breakdown spectroscopy (LIBS) with nanosecond pulses and compared to three nonpathogenic E. coli strains: a laboratory strain of K-12 (AB), a derivative of the same strain termed HF4714, and an environmental strain, E. coli C (Nino C). A discriminant function analysis (DFA) was performed on the LIBS spectra obtained from live colonies of all four strains. Utilizing the emission intensity of 19 atomic and ionic transitions from trace inorganic elements, the DFA revealed significant differences between EHEC and the Nino C strain, suggesting the possibility of identifying and discriminating the pathogenic strain from commonly occurring environmental strains. EHEC strongly resembled the two K-12 strains, in particular, HF4714, making discrimination between these strains difficult. DFA was also used to analyze spectra from two of the nonpathogenic strains cultured in different media: on a trypticase soy (TS) agar plate and in a liquid TS broth. Strains cultured in different media were identified and effectively discriminated, being more similar than different strains cultured in identical media. All bacteria spectra were completely distinct from spectra obtained from the nutrient medium or ablation substrate alone. The ability to differentiate strains prepared and tested in different environments indicates that matrix effects and background contaminations do not necessarily preclude the use of LIBS to identify bacteria found in a variety of environments or grown under different conditions.

  6. White-light diffraction tomography of unlabelled live cells

    NASA Astrophysics Data System (ADS)

    Kim, Taewoo; Zhou, Renjie; Mir, Mustafa; Babacan, S. Derin; Carney, P. Scott; Goddard, Lynford L.; Popescu, Gabriel

    2014-03-01

    We present a technique called white-light diffraction tomography (WDT) for imaging microscopic transparent objects such as live unlabelled cells. The approach extends diffraction tomography to white-light illumination and imaging rather than scattering plane measurements. Our experiments were performed using a conventional phase contrast microscope upgraded with a module to measure quantitative phase images. The axial dimension of the object was reconstructed by scanning the focus through the object and acquiring a stack of phase-resolved images. We reconstructed the three-dimensional structures of live, unlabelled, red blood cells and compared the results with confocal and scanning electron microscopy images. The 350 nm transverse and 900 nm axial resolution achieved reveals subcellular structures at high resolution in Escherichia coli cells. The results establish WDT as a means for measuring three-dimensional subcellular structures in a non-invasive and label-free manner.

  7. Toxicity of dysprosium nano particles with glucose and sodium chloride on E. Coli

    NASA Astrophysics Data System (ADS)

    Anaya, N. M.; Solomon, F.; Oyanedel-Craver, V.

    2013-12-01

    Application of rare earth elements (REEs) such as, dysprosium nanoparticles (nDy), to the biomedical field are increasing due to their paramagnetic properties. Current applications of nDy in the biomedical field are in MRI screening and anti-cancer therapy. Environmental impacts of nDy released into the environment are unknown or poorly understood and are a concern due to the lack of appropriate recycling systems. The objective of this toxicological study is to assess the impacts of nDy at relevant environmental concentrations on Escherichia coli. A range of glucose concentrations were used to evaluate the impact under different aerobic metabolic stages when the bacteria are exposed to the nanoparticles. Two traditional techniques used to evaluate the physiological response of E. coli at different environmental conditions were dual staining with fluorescent dyes (Live/Dead BacLight viability kit) and respirometric assays. A high-through put array-based methodology was implemented to provide additional toxicity testing. Preliminary toxicology results for both traditional techniques showed a positive trend between nDy and carbon source concentrations. High concentrations of nDy (>5mg/L) in environments with high glucose concentration (>210mg/L) are more toxic to E. coli than environments with low glucose concentrations. On the other hand, Live/Dead experiments showed higher toxicity effect in comparison to the respirometric tests using the same exposure conditions, suggesting that even at high membrane disruption the bacteria can still performed some metabolic activity.

  8. Application of Noncanonical Amino Acids for Protein Labeling in a Genomically Recoded Escherichia coli.

    PubMed

    Kipper, Kalle; Lundius, Ebba G; Ćurić, Vladimir; Nikić, Ivana; Wiessler, Manfred; Lemke, Edward A; Elf, Johan

    2017-02-17

    Small synthetic fluorophores are in many ways superior to fluorescent proteins as labels for imaging. A major challenge is to use them for a protein-specific labeling in living cells. Here, we report on our use of noncanonical amino acids that are genetically encoded via the pyrrolysyl-tRNA/pyrrolysyl-RNA synthetase pair at artificially introduced TAG codons in a recoded E. coli strain. The strain is lacking endogenous TAG codons and the TAG-specific release factor RF1. The amino acids contain bioorthogonal groups that can be clicked to externally supplied dyes, thus enabling protein-specific labeling in live cells. We find that the noncanonical amino acid incorporation into the target protein is robust for diverse amino acids and that the usefulness of the recoded E. coli strain mainly derives from the absence of release factor RF1. However, the membrane permeable dyes display high nonspecific binding in intracellular environment and the electroporation of hydrophilic nonmembrane permeable dyes severely impairs growth of the recoded strain. In contrast, proteins exposed on the outer membrane of E. coli can be labeled with hydrophilic dyes with a high specificity as demonstrated by labeling of the osmoporin OmpC. Here, labeling can be made sufficiently specific to enable single molecule studies as exemplified by OmpC single particle tracking.

  9. Wild birds and urban pigeons as reservoirs for diarrheagenic Escherichia coli with zoonotic potential.

    PubMed

    Borges, Clarissa A; Cardozo, Marita V; Beraldo, Livia G; Oliveira, Elisabete S; Maluta, Renato P; Barboza, Kaline B; Werther, Karin; Ávila, Fernando A

    2017-03-09

    In order to describe the role of wild birds and pigeons in the transmission of shiga toxigenic Escherichia coli (STEC) and enteropathogenic Escherichia coli (EPEC) to humans and other animals, samples were collected from cloacae and oropharynx of free-living wild birds and free-living pigeons. Two STEC (0.8%) and five EPEC strains (2.0%) were isolated from wild birds and four EPEC strains (2.0%) were recovered from pigeons. Serogroups, sequence types (STs) and virulence genes, such as saa, iha, lpfA O113, ehxA, espA, nleB and nleE, detected in this study had already been implicated in human and animal diseases. Multidrug resistance (MDR) was found in 25.0% of the pigeon strains and in 57.0% of the wild bird strains; the wild birds also yielded one isolate carrying extended-spectrum β-lactamases (ESBLs) gene bla CTX-M-8. The high variability shown by PFGE demonstrates that there are no prevalent E. coli clones from these avian hosts. Wild birds and pigeons could act as carriers of multidrug-resistant STEC and EPEC and therefore may constitute a considerable hazard to human and animal health by transmission of these strains to the environment.

  10. Campylobacter jejuni Increases Flagellar Expression and Adhesion of Noninvasive Escherichia coli: Effects on Enterocytic Toll-Like Receptor 4 and CXCL-8 Expression

    PubMed Central

    Reti, Kristen L.; Tymensen, Lisa D.; Davis, Shevaun P.; Amrein, Matthias W.

    2015-01-01

    Campylobacter jejuni is the most common cause of bacterium-induced gastroenteritis, and while typically self-limiting, C. jejuni infections are associated with postinfectious intestinal disorders, including flares in patients with inflammatory bowel disease and postinfectious irritable bowel syndrome (PI-IBS), via mechanisms that remain obscure. Based on the hypothesis that acute campylobacteriosis may cause pathogenic microbiota dysbiosis, we investigated whether C. jejuni may activate dormant virulence genes in noninvasive Escherichia coli and examined the epithelial pathophysiological consequences of these alterations. Microarray and quantitative real-time PCR analyses revealed that E. coli adhesin, flagellum, and hemolysin gene expression were increased when E. coli was exposed to C. jejuni-conditioned medium. Increased development of bacterial flagella upon exposure to live C. jejuni or C. jejuni-conditioned medium was observed under transmission electron microscopy. Atomic force microscopy demonstrated that the forces of bacterial adhesion to colonic T84 enterocytes, and the work required to rupture this adhesion, were significantly increased in E. coli exposed to C. jejuni-conditioned media. Finally, C. jejuni-modified E. coli disrupted TLR4 gene expression and induced proinflammatory CXCL-8 gene expression in colonic enterocytes. Together, these data suggest that exposure to live C. jejuni, and/or to its secretory-excretory products, may activate latent virulence genes in noninvasive E. coli and that these alterations may directly trigger proinflammatory signaling in intestinal epithelia. These observations shed new light on mechanisms that may contribute, at least in part, to postcampylobacteriosis inflammatory disorders. PMID:26371123

  11. Active Living: Promoting Healthy Lifestyles.

    ERIC Educational Resources Information Center

    Swedburg, Randy B.; Izso, Bill

    1994-01-01

    Active Living is a unique Canadian approach in which physical activity is valued and integrated into daily life. Active Living will have an increasing impact on the health, physical education, and recreation fields. The article describes the development of Active Living, its effects on Canadian society, and current initiatives. (SM)

  12. RACE AS LIVED EXPERIENCE

    PubMed Central

    Garcia, John A.; Sanchez, Gabriel R.; Sanchez-Youngman, Shannon; Vargas, Edward D.; Ybarra, Vickie D.

    2015-01-01

    A growing body of social science research has sought to conceptualize race as a multidimensional concept in which context, societal relations, and institutional dynamics are key components. Utilizing a specially designed survey, we develop and use multiple measures of race (skin color, ascribed race, and discrimination experiences) to capture race as “lived experience” and assess their impact on Latinos’ self-rated health status. We model these measures of race as a lived experience to test the explanatory power of race, both independently and as an integrated scale with categorical regression, scaling, and dimensional analyses. Our analyses show that our multiple measures of race have significant and negative effects on Latinos’ self-reported health. Skin color is a dominant factor that impacts self-reported health both directly and indirectly. We then advocate for the utilization of multiple measures of race, adding to those used in our analysis, and their application to other health and social outcomes. Our analysis provides important contributions across a wide range of health, illness, social, and political outcomes for communities of color. PMID:26681972

  13. Living Longer in Mexico

    PubMed Central

    Aguila, Emma; Diaz, Claudia; Fu, Mary Manqing; Kapteyn, Arie; Pierson, Ashley

    2012-01-01

    Abstract This analysis of aging and income security in Mexico establishes that the older population in Mexico is increasing quickly and that this population is especially vulnerable to poverty. Mexican citizens are living longer and overall have experienced an improvement in the quality of life compared to that of prior generations. However, this study demonstrates that social improvements are not affecting the daily lives of all persons equally. The authors attempt to uncover and highlight those differences. One of the primary challenges facing Mexico is a growing older population. The demographic transition in Mexico combined with the lack of formal sources of income in retirement place many older persons in a state of financial insecurity. The information contained in this study and the proposed policy research areas are intended to enlarge the portfolio of options for older Mexicans. The authors analyze wealth and sources of income during retirement, the relationship between health and wealth, urban and rural disparities, and the impact of migration spells to the United States on wealth accumulation and health insurance in Mexico. PMID:28083208

  14. Study of mechanical properties of DNA in E. coli cells by fluorescence correlation spectroscopy

    NASA Astrophysics Data System (ADS)

    Kafle, Rudra; Liebeskind, Molly; Meiners, Jens-Christian

    Mechanical quantities like the elasticity of cells are conventionally measured by directly probing them mechanically. Measurements of these quantities for subcellular structures in living cells are almost impossible this way. We use fluorescence correlation spectroscopy (FCS) to measure such mechanical quantities in chromosomal DNA in E. coli cells. We present methods to address complexities of live-cell FCS such as photobleaching, and calculate the viscoelastic moduli from the FCS data. We compare the measured viscoelastic moduli of live cells with those that are ATP-depleted to stop all molecular motor action and find substantial differences. Active processes are stopped in ATP-depleted cells and hence the bacterial DNA appears to become stiffer and the surrounding intracellular medium more viscous. We also compare our results with the FCS data obtained from the lambda DNA solution in various concentrations to mimic the cellular environment.

  15. Utilization of high temperature compost in space agriculture: the model compost kills Escherichia coli

    NASA Astrophysics Data System (ADS)

    Oshima, Tairo; Moriya, Toshiyuki; Yoshii, Takahiro

    The author and his colleagues have proposed the use of high temperature composting in space inhabitation. Composting has many advantages over burning in organic waste treatments. Composting is self-heating processes and needs no extra fuel. Composting requires no sophis-ticated equipment such as an incinerator. Composting emits no hazardous gases such as NOx, SOx and dioxines which are often produced by burning. The final product can be used as fer-tilizer in space farm land; resources recycling society can be constructed in space stations and space cities. In addition to these advantages, composting and compost soil may contribute to the environmental cleanup. During composting processes, harmful compounds to agricultural plants and animals can be destroyed. Seeds of weeds can be killed by high heat. Likewise pathogenic microbes in the waste can be eliminated during fermentation inside the composts. Recently we measured the survivability of E. coli in compost. E. coli was used as the represen-tative of the Gram-negative bacteria. Since many pathogenic strains belong to Gram-negative bacteria and Gram-negative bacteria are more resistant to antibiotics than gram-positive bac-teria. When E. coli cells were mixed in the compost pile of which inside temperature reaches up to 75oC, they died within a short period as expected. However, E. coli DNA was detected even after a day in high temperature compost. RNA has a shorter life-span than DNA, but was detected after incubation in compost for several hours. In addition to sterilizing effects due to high temperature, we found our compost soil has E. coli killing activity. When mixed with the compost soil at room temperature, E. coli died gradually. Extract of the compost soil also killed E. coli at room temperature, but it took a few days to eliminate E. coli completely. During the killing process, total number of living bacteria did not change, indicating that the killing activity is limited to some specific

  16. High-resolution mapping of architectural DNA binding protein facilitation of a DNA repression loop in Escherichia coli

    PubMed Central

    Becker, Nicole A.; Maher, L. James

    2015-01-01

    Double-stranded DNA is a locally inflexible polymer that resists bending and twisting over hundreds of base pairs. Despite this, tight DNA bending is biologically important for DNA packaging in eukaryotic chromatin and tight DNA looping is important for gene repression in prokaryotes. We and others have previously shown that sequence nonspecific DNA kinking proteins, such as Escherichia coli heat unstable and Saccharomyces cerevisiae non-histone chromosomal protein 6A (Nhp6A), facilitate lac repressor (LacI) repression loops in E. coli. It has been unknown if this facilitation involves direct protein binding to the tightly bent DNA loop or an indirect effect promoting global negative supercoiling of DNA. Here we adapt two high-resolution in vivo protein-mapping techniques to demonstrate direct binding of the heterologous Nhp6A protein at a LacI repression loop in living E. coli cells. PMID:26039992

  17. High-resolution mapping of architectural DNA binding protein facilitation of a DNA repression loop in Escherichia coli.

    PubMed

    Becker, Nicole A; Maher, L James

    2015-06-09

    Double-stranded DNA is a locally inflexible polymer that resists bending and twisting over hundreds of base pairs. Despite this, tight DNA bending is biologically important for DNA packaging in eukaryotic chromatin and tight DNA looping is important for gene repression in prokaryotes. We and others have previously shown that sequence nonspecific DNA kinking proteins, such as Escherichia coli heat unstable and Saccharomyces cerevisiae non-histone chromosomal protein 6A (Nhp6A), facilitate lac repressor (LacI) repression loops in E. coli. It has been unknown if this facilitation involves direct protein binding to the tightly bent DNA loop or an indirect effect promoting global negative supercoiling of DNA. Here we adapt two high-resolution in vivo protein-mapping techniques to demonstrate direct binding of the heterologous Nhp6A protein at a LacI repression loop in living E. coli cells.

  18. Use of bioluminescent Escherichia coli O157:H7 to study intra-protozoan survival of bacteria within Tetrahymena pyriformis.

    PubMed

    Nelson, Shona M; Cooper, Alison A A; Taylor, Elaine L; Salisbury, Vyvyan C

    2003-06-06

    A method was developed that enabled real-time monitoring of the uptake and survival of bioluminescent Escherichia coli O157 within the freshwater ciliate Tetrahymena pyriformis. Constitutively bioluminescent E. coli O157 pLITE27 was cocultured with T. pyriformis in nutrient-deficient (Chalkley's) and in nutrient-rich (proteose peptone, yeast extract) media. Non-internalised bacteria were inactivated by addition of colistin, indicated by a decline in bioluminescence. Protozoa were subsequently lysed with Triton X-100 which lead to a further drop in bioluminescence, consistent with release of live internal bacteria from T. pyriformis into the colistin-containing environment. Bioluminescence measurements for non-lysed cultures indicated that internalised E. coli O157 pLITE27 cells were only slowly digested by T. pyriformis, in both media, over the time period studied. The results suggest that bioluminescent bacteria are useful tools in the study of bacterial intra-protozoan survival.

  19. Live From the Poles

    NASA Astrophysics Data System (ADS)

    Linder, C. A.; Kent, J.; Lippsett, L.

    2006-12-01

    International Polar Year presents an extraordinary opportunity to educate students and the public about science at the icy ends of the Earth. The goal of our proposal is to apply collaborative multimedia approaches to bring the story of four polar research expeditions to the general public and the classroom. The four expeditions (measurement of ice sheet dynamics in Greenland, a study of the McMurdo ecosystem over austral winter, installation of a buoy array in the Beaufort Gyre, and exploration of the Gakkel Ridge) were chosen based on their broad range of disciplines and relevance to the three primary IPY research emphasis areas defined by NSF. A science writer and a professional photographer will join each expedition and file dispatches for a daily Webcast. The posting will feature science updates, logistical challenges, team member profiles, and life at sea (or on the ice). The writer will also coordinate real-time phone patches from PIs in the field to audiences at the Museum of Science, Boston, the Smithsonian National Museum of Natural History, The Field Museum, Chicago, the Houston Museum of Natural Science, the Birch Aquarium, San Diego, the Pacific Science Center, Seattle, National Public Radio "Talk of the Nation: Science Friday," CBS News, and to student "reporters" writing for Scholastic Online. At the museums, the "Live from the Ice" interactive phone calls will be preceded by a background presentation by a scientist, who will also moderate the live discussion between the public and researchers in the field. A 20-30 minute satellite phone call will allow the public to ask the researchers questions about their research while it's happening. In addition to building and promoting an online experience, a museum exhibit featuring models of Arctic instruments and informative kiosks will be developed at the Woods Hole Oceanographic Institution Exhibit Center. Each of our partner museums will also provide a "leave-behind" component to continue to educate

  20. Women's lives, mothers' health.

    PubMed

    Chauliac, M; Masse-raimbault, A M

    1985-01-01

    This document dealing with women's lives and the health of mothers identifies factors conditioning the health and nutritional status of women and girls (life expectancy at birth, maternal mortality rate, and the birthrate); considers nutritional requirements of pregnant and lactating women, weight gain during preganncy, mothers' age and number of children and interbirth interval, maternal nutritional status and breastfeeding, anemia, work and women's health, pregnancy in adolescents, abortion, the growth of small girls and its effect on future pregnancies, and sexual mutilations; and reports on actions aimed at improving the health of women as well as health problems facing rural women. The 3 key concepts of this reflection on women's lives are: women's health should be taken into account as well as children's health; the development of the whole human being should be respected, implying ongoing surveillance of the health status of women and of their children; and the overall living conditions of women within the family and society must be analyzed at the different phases of their life, so as to encourage integrated actions rather than various uncoordinated efforts. Women's health status, like the health status of everyone, depends on a multitude of socioeconomic and sanitational factors. A figure illustrates several of the many interrelations between the various factors which influence the nutritional status of all individuals. Women of childbearing age are at greater risk than other population groups, due to their reproductive function and their ability to nurse children: pregnancy, like lactation, generates metabolic changes and increases nutritional needs. Delivery itself presents a series of risks for the woman's health, and only regular surveillance of pregnancy may prevent many of these. A woman's health status and, most of all her nutritional status during pregnancy and delivery, condition her future health and ability to assume her many tasks as well as

  1. Living with hypertrophic cardiomyopathy.

    PubMed

    Subasic, Kim

    2013-12-01

    The purpose of this study is to provide an insider's account of what it is like to live with hypertrophic cardiomyopathy (HCM), a genetic cardiovascular illness that carries the risk for sudden cardiac death. This study aims to reveal how HCM impacts the family and guides the decision whether or not to pursue genetic testing, how the physical limitations associated with HCM alter being-in-the-world, and how HCM alters social relationships. Fifteen adults with HCM were recruited for a longitudinal, phenomenological, qualitative study through purposive sampling and word of mouth. A total of 45 interviews were conducted by the researcher at a time and place designated by the participant between August 2011 and January 2012. The first interview with each participant was conducted in person. While efforts were made to conduct all interviews in person, a total of three interviews were conducted by telephone as requested by three participants due to scheduling conflicts. Through methods of interpretive phenomenology, three audio-recorded, semistructured interviews occurred over the course of 3 months. Detailed narratives were solicited and transcribed verbatim. Methodological and analytical documentation was supported with the identification of key phrases, similar experiences, themes, and documentation of the rationale for decisions throughout the research process. Participation in genetic testing carries a multitude of personal, familial, financial, and emotional implications. The results of a genetic test elicited an emotional response regardless of whether the results were negative, positive, or inconclusive. Living with a potentially life-threatening illness altered identity, disrupted social relationships, and generated chronic fear and uncertainty. A new normal was re-ordered or transformed by the demands and limitations posed by HCM, and by the person's concerns, priorities, and the meaning of the illness. Results from this study underscore the need for healthcare

  2. Engineering of a synthetic electron conduit in living cells

    PubMed Central

    Jensen, Heather M.; Albers, Aaron E.; Malley, Konstantin R.; Londer, Yuri Y.; Cohen, Bruce E.; Helms, Brett A.; Weigele, Peter; Groves, Jay T.; Ajo-Franklin, Caroline M.

    2010-01-01

    Engineering efficient, directional electronic communication between living and nonliving systems has the potential to combine the unique characteristics of both materials for advanced biotechnological applications. However, the cell membrane is designed by nature to be an insulator, restricting the flow of charged species; therefore, introducing a biocompatible pathway for transferring electrons across the membrane without disrupting the cell is a significant challenge. Here we describe a genetic strategy to move intracellular electrons to an inorganic extracellular acceptor along a molecularly defined route. To do so, we reconstitute a portion of the extracellular electron transfer chain of Shewanella oneidensis MR-1 into the model microbe Escherichia coli. This engineered E. coli can reduce metal ions and solid metal oxides ∼8× and ∼4× faster than its parental strain. We also find that metal oxide reduction is more efficient when the extracellular electron acceptor has nanoscale dimensions. This work demonstrates that a genetic cassette can create a conduit for electronic communication from living cells to inorganic materials, and it highlights the importance of matching the size scale of the protein donors to inorganic acceptors. PMID:20956333

  3. 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

  4. Speciation of selenite and selenate using living bacteria.

    PubMed

    Robles, L C; Feo, J C; de Celis, B; Lumbreras, J M; García-Olalla, C; Aller, A J

    1999-09-13

    In this work, a reliable method is described for speciation of soluble inorganic selenium ions, Se(IV) and Se(VI), which combines an uptake process by using living bacterial cells and electrothermal atomic absorption spectrometry (ETAAS). A selective retention of either Se(IV) or Se(IV) plus Se(VI) can be carried out by using the uptake system made up of either Pseudomonas putida or Escherichia coli strains cultivated in a culture medium based on glucose (P. putida) and glucose plus dipotassium phosphate (E. coli) mixed together with the original sample solution containing the selenium species. Discrimination between inorganic selenium species is possible by combining the optimization of the bacterial cell, the growth conditions and the relative rates of their retention from the sample. In the general procedure, an equilibrium between the analyte in the solution and the uptake system is allowed to be established, and then the concentration of selenium is determined directly in the biomass by slurry sampling ETAAS. Nonetheless, a theoretical model is proposed to describe the retention process by the living bacterial cells, which also provides a feasible quantification of the extraction process before the adsorption equilibrium is reached and whenever the agitation conditions and the sampling time are under control. The detection limits for the inorganic selenium species at the best retention conditions are of 5.7 ng Se(IV) ml(-1) for P. putida and 6.1 ng Se(IV) ml(-1) and 6.3 ng Se(VI) ml(-1) for E. coli. The relative standard deviations of the adsorption/determination process are 2.9-6.3%.

  5. The unexhausted potential of E. coli

    PubMed Central

    Blount, Zachary D

    2015-01-01

    E. coli's hardiness, versatility, broad palate and ease of handling have made it the most intensively studied and best understood organism on the planet. However, research on E.coli has primarily examined it as a model organism, one that is abstracted from any natural history. But E. coli is far more than just a microbial lab rat. Rather, it is a highly diverse organism with a complex, multi-faceted niche in the wild. Recent studies of ‘wild’ E. coli have, for example, revealed a great deal about its presence in the environment, its diversity and genomic evolution, as well as its role in the human microbiome and disease. These findings have shed light on aspects of its biology and ecology that pose far-reaching questions and illustrate how an appreciation of E. coli's natural history can expand its value as a model organism. DOI: http://dx.doi.org/10.7554/eLife.05826.001 PMID:25807083

  6. 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.

  7. Transmission OF Campylobacter coli in chicken embryos

    PubMed Central

    Rossi, Daise Aparecida; Fonseca, Belchiolina Beatriz; de Melo, Roberta Torres; Felipe, Gutembergue da Silva; da Silva, Paulo Lourenço; Mendonça, Eliane Pereira; Filgueiras, Ana Luzia Lauria; Beletti, Marcelo Emilio

    2012-01-01

    Campylobacter coli is an important species involved in human cases of enteritis, and chickens are carriers of the pathogen mainly in developing country. The current study aimed to evaluate the transmission of C. coli and its pathogenic effects in chicken embryos. Breeder hens were inoculated intra-esophageally with C. coli isolated from chickens, and their eggs and embryos were analyzed for the presence of bacteria using real-time PCR and plate culture. The viability of embryos was verified. In parallel, SPF eggs were inoculated with C. coli in the air sac; after incubation, the embryos were submitted to the same analysis as the embryos from breeder hens. In embryos and fertile eggs from breeder hens, the bacterium was only identified by molecular methods; in the SPF eggs, however, the bacterium was detected by both techniques. The results showed no relationship between embryo mortality and positivity for C. coli in the embryos from breeder hens. However, the presence of bacteria is a cause of precocious mortality for SPF embryos. This study revealed that although the vertical transmission is a possible event, the bacteria can not grow in embryonic field samples. PMID:24031861

  8. Behavior of non-O157 Shiga toxin-producing Escherichia coli, enteroinvasive E. coli, enteropathogenic E. coli, and enterotoxigenic E. coli strains on alfalfa sprouts.

    PubMed

    Gómez-Aldapa, Carlos A; Rangel-Vargas, Esmeralda; Torres-Vitela, M Del Refugio; Villarruel-López, Angélica; Castro-Rosas, Javier

    2013-08-01

    Data about the behavior of non-O157 Shiga toxin-producing Escherichia coli (non-O157 STEC), enteroinvasive E. coli (EIEC), enterotoxigenic E. coli (ETEC), and enteropathogenic E. coli (EPEC) on seeds and alfalfa sprouts are not available. The behavior of STEC, EIEC, ETEC, and EPEC was determined during germination and sprouting of alfalfa seeds at 20 ± 2°C and 30 ± 2°C and on alfalfa sprouts at 3 ± 2°C. When alfalfa seeds were inoculated with STEC, EIEC, ETEC, or EPEC strains, all these diarrheagenic E. coli pathotypes (DEPs) grew during germination and sprouting of seeds, reaching counts of approximately 5 and 6 log CFU/g after 1 day at 20 ± 2°C and 30 ± 2°C, respectively. However, when the sprouts were inoculated after 1 day of seed germination and stored at 20 ± 2°C or 30 ± 2°C, no growth was observed for any DEP during sprouting at 20 ± 2°C or 30 ± 2°C for 9 days. Refrigeration reduced significantly (P < 0.0.5) the number of viable DEPs on sprouts after 20 days in storage; nevertheless, these decreases have no practical significance for the safety of the sprouts.

  9. Current Interventions for Controlling Pathogenic Escherichia coli.

    PubMed

    Kim, Nam Hee; Cho, Tae Jin; Rhee, Min Suk

    2017-01-01

    This review examined scientific reports and articles published from 2007 to 2016 regarding the major environmental sources of pathogenic Escherichia coli and the routes by which they enter the human gastrointestinal tract. The literature describes novel techniques used to combat pathogenic E. coli transmitted to humans from livestock and agricultural products, food-contact surfaces in processing environments, and food products themselves. Although prevention before contamination is always the best "intervention," many studies aim to identify novel chemical, physical, and biological techniques that inactivate or eliminate pathogenic E. coli cells from breeding livestock, growing crops, and manufactured food products. Such intervention strategies target each stage of the food chain from the perspective of "Farm to Table food safety" and aim to manage major reservoirs of pathogenic E. coli throughout the entire process. Issues related to, and recent trends in, food production must address not only the safety of the food itself but also the safety of those who consume it. Thus, research aims to discover new "natural" antimicrobial agents and to develop "multiple hurdle technology" or other novel technologies that preserve food quality. In addition, this review examines the practical application of recent technologies from the perspective of product quality and safety. It provides comprehensive insight into intervention measures used to ensure food safety, specifically those aimed at pathogenic E. coli. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. The 503nm pigment of Escherichia coli

    PubMed Central

    Kamitakahara, Joyce R.; Polglase, W. J.

    1970-01-01

    The yield of cell protein was one-third less for streptomycin-dependent Escherichia coli B than for the wild-type parent strain when both were grown aerobically on a medium with limiting glucose, but anaerobically the yield of protein was similar for both strains. The transient pigment absorbing at 503nm that is known to be present in E. coli and other organisms was not detectable in streptomycin-dependent mutants nor in a non-dependent (energy-deficient) revertant. When wild-type E. coli B was grown on limiting glucose–salts medium containing 2,4 dinitrophenol, the yield of cell protein was decreased and formation of the 503nm pigment was inhibited. Fumarase, aconitase and glucose 6-phosphate dehydrogenase were de-repressed in E. coli B cells grown with excess of glucose in a medium containing 2,4-dinitrophenol. In air-oxidized, wild-type E. coli B cells, the 503nm pigment appeared before reduced cytochromes when gluconate was the substrate but failed to appear when succinate was the substrate. The results provide evidence for a role of the 503nm pigment in aerobic energy metabolism, possibly as an electron acceptor from NADPH. PMID:4395501

  11. Freezing of living cells

    SciTech Connect

    Mazur, P.

    1985-01-01

    It can be calculated that a living cell will survive more than 5000 years at -196/sup 0/C. This ability to essentially stop biological time has important implications in medicine and agriculture, and in biological research. In medicine the chief implications are in the banking of transplantable tissues and organs and in in vitro fertilization. In agriculture the applications stem in part from the role of frozen embryos in amplifying the number of calves produced by high quanlity cows. The problem is how can cells survive both the cooling to such very low temperatures and the return to normal temperatures. The answers involve fundamental characteristics of cells such as the permeability of their surface membranes to water and solutes. These characteristics determine whether or not cells undergo lethal internal ice formation and other response during freezing and thawing. 27 refs., 12 figs.

  12. Living on the edge.

    PubMed

    Hinrichsen, D

    1989-01-01

    A brief update on the destruction of the environment is given. The concern is for the coastal waters and rivers which are polluted daily by raw sewage, industrial waste, and sedimentation, e.g., the Juru in Malaysia, the Pasig in the Philippines, and the Chao Phraya in Thailand are open sewers by the time the rivers reach the sea or bay. Metropolitan Manila's river is said to be biologically dead from pollution, and the bays of Manila and Jakarta suffer from oxygen depletion. Unfortunately, the coastal area maintains population as well as the wealth of marine life. In the US in 1990, 75% of the population will live within 50 miles of a shore including the Great Lakes. 30 southeast Asia's 50 largest cities are located on or near a coast. Over fishing, over population, over developing, and over exploitation are unacceptable; the alternative is for man to correct his mistakes.

  13. Gaia Live in School

    NASA Astrophysics Data System (ADS)

    Walton, N. A.; Barnes, R.; Soubiran, C.; Vogt, S.

    2014-07-01

    Gaia is the European Space Agency's (ESA) next major astronomy telescope mission that was launched December 19, 2013. Gaia will measure accurate distances to about one billion stars across our Milky Way, allowing us to better understand how our galaxy formed and evolved. Gaia will have a profound impact on our understand ing of the Universe and the nature of dark matter, and provide a deeper understanding of how planets form around stars in our local neighbourhood. Gaia scientists and science education advisors are organising a Gaia post-launch event to link approximately forty schools across Europe. The event will include a live stream connection to ESA Gaia Mission Control and local Gaia research students to act as “explainers” and give practical demonstrations in each school. This paper describes the challenges in conducting this Europe-wide event.

  14. Can lean save lives?

    PubMed

    Fillingham, David

    2007-01-01

    The purpose of this paper is to show how over the last 18 months Bolton Hospitals NHS Trust have been exploring whether or not lean methodologies, often known as the Toyota Production System, can indeed be applied to healthcare. This paper is a viewpoint. One's early experience is that lean really can save lives. The Toyota Production System is an amazingly successful way of manufacturing cars. It cannot be simply translated unthinkingly into a hospital but lessons can be learned from it and the method can be adapted and developed so that it becomes owned by healthcare staff and focused towards the goal of improved patient care. Working in healthcare is a stressful and difficult thing. Everyone needs a touch of inspiration and encouragement. Applying lean to healthcare in Bolton seems to be achieving just that for those who work there.

  15. Incentivizing living organ donation.

    PubMed

    Cynowiec, Jessica; Kim, Jennifer; Qazi, Yasir A

    2009-04-01

    The number of organs available for the patients on the transplant waitlist remains at a disproportionate low. All possible methods to curtail this shortage, including providing donors with incentives, have been proposed. This article reviews recent publications addressing the benefits and risks involved in incentivizing living donation. The debate about the ethics, feasibility, and possible models for compensating organ donors has been prominent in recent literature. As certain countries take lead on this initiative, others are cautiously weighing in on the impact implementations of such policies may have on the society, especially on the underprivileged. The shortage of organs has resulted in proposal of strategies that encroach on certain moral and ethical principles. Providing incentives to donors is one such strategy that is likely to receive a lot of attention in the next few years.

  16. Characterizing Pilus-Mediated Adhesion of Biofilm-Forming E. coli to Chemically Diverse Surfaces Using Atomic Force Microscopy

    PubMed Central

    2013-01-01

    Biofilms are complex communities of microorganisms living together at an interface. Because biofilms are often associated with contamination and infection, it is critical to understand how bacterial cells adhere to surfaces in the early stages of biofilm formation. Even harmless commensal Escherichia coli naturally forms biofilms in the human digestive tract by adhering to epithelial cells, a trait that presents major concerns in the case of pathogenic E. coli strains. The laboratory strain E. coli ZK1056 provides an intriguing model system for pathogenic E. coli strains because it forms biofilms robustly on a wide range of surfaces.E. coli ZK1056 cells spontaneously form living biofilms on polylysine-coated AFM cantilevers, allowing us to measure quantitatively by AFM the adhesion between native biofilm cells and substrates of our choice. We use these biofilm-covered cantilevers to probe E. coli ZK1056 adhesion to five substrates with distinct and well-characterized surface chemistries, including fluorinated, amine-terminated, and PEG-like monolayers, as well as unmodified silicon wafer and mica. Notably, after only 0–10 s of contact time, the biofilms adhere strongly to fluorinated and amine-terminated monolayers as well as to mica and weakly to “antifouling” PEG monolayers, despite the wide variation in hydrophobicity and charge of these substrates. In each case the AFM retraction curves display distinct adhesion profiles in terms of both force and distance, highlighting the cells’ ability to adapt their adhesive properties to disparate surfaces. Specific inhibition of the pilus protein FimH by a nonhydrolyzable mannose analogue leads to diminished adhesion in all cases, demonstrating the critical role of type I pili in adhesion by this strain to surfaces bearing widely different functional groups. The strong and adaptable binding of FimH to diverse surfaces has unexpected implications for the design of antifouling surfaces and antiadhesion therapies

  17. Antimicrobial Resistance and Molecular Characterization of Extended-Spectrum β-Lactamases and Other Escherichia coli Isolated from Food of Animal Origin and Human Intestinal Isolates.

    PubMed

    Krizman, Manja; Avgustin, Jerneja Ambrozic; Zdovc, Irena; Golob, Majda; Trkov, Marija; Ciglenecki, Urska Jamnikar; Biasizzo, Majda; Kirbis, Andrej

    2017-01-01

    Antibiotics have always appeared miraculous, saving innumerable lives. However, the unwise use of antimicrobial drugs has led to the appearance of resistant bacteria. The purpose of this study was to evaluate antimicrobial resistance in Escherichia coli (n =160) isolated from food of animal origin. The focus was on E. coli -producing extended-spectrum β-lactamases. E. coli was chosen because it is a part of the normal microbiota in mammals and can enter the food chain during slaughtering and food manipulation. Subsequently, its resistance genes can be transferred to pathogenic bacteria and human microbiota. Phenotypic and genotypic analyses of selected antimicrobial resistances were carried out together with a molecular analysis of virulence genes. E. coli isolates from food of animal origin were compared with clinical E. coli strains isolated from the human intestinal tract. Extended-spectrum β-lactamase-producing E. coli isolates were found in 9.4% of food isolates and in 1.8% of intestinal isolates. Phylogenetically, the majority of food (86.3%) and intestinal E. coli (58.1%) isolates were found to belong to the commensal phylogenetic groups A and B1. The distribution of 4 of 14 analyzed virulence factors was similar in the food and intestinal isolates. Strains isolated from food in Slovenia harbored resistance genes and virulence factors, which can constitute a problem for food safety if not handled properly.

  18. Living Liquid Crystals.

    SciTech Connect

    Zhou, Shuang; Sokolov, Andrey; Lavrentovich, Oleg D.; Aranson, Igor S.

    2014-01-28

    Collective motion of self-propelled organisms or synthetic par­ticles, often termed •active fluid,• has attracted enormous atten­tion in the broad scientific community because of its fundamentally nonequilibrium nature. Energy input and interactions among the moving units and the medium lead to complex dynamics. Here,we introduce a class of active matter-living liquid crystals (UCs}­ that combines living swimming bacteria with a lyotropic liquid crystal. The physical properties of LLCs can be controlled by the amount of oxygen available to bacteria, by concentration of ingre­dients, or by temperature. Our studies reveal a wealth of intriguing dynamic phenomena. caused by the coupling between the activity-triggered flow and long-range orientational order of the medium. Among these are (i) nonlinear trajectories of bacterial motion guided by nonuniform director, (ii) local melting of the liquid crystal caused by the bacteria-produced shear flows, (iii) activity-triggered transition from a nonflowing uniform state into a flowing one-dimensional periodic pattern and its evolution into a turbulent array of topological defects, and (iv) birefringence­ enabled visualization of microflow generated by the nanometers­ thick bacterial flagella. Unlike their isotropic counterpart, the LLCs show collective dynamic effects at very low volume fraction of bacteria, on the order of 0.2%. Our work suggests an unorthodox design concept to control and manipulate the dynamic behavior of soft active matter and opens the door for potential biosensing and biomedical applications.

  19. The repertoire of DNA-binding transcriptional regulators in Escherichia coli K-12.

    PubMed

    Pérez-Rueda, E; Collado-Vides, J

    2000-04-15

    Using a combination of several approaches we estimated and characterized a total of 314 regulatory DNA-binding proteins in Escherichia coli, which might represent its minimal set of transcription factors. The collection is comprised of 35% activators, 43% repressors and 22% dual regulators. Within many regulatory protein families, the members are homogeneous in their regulatory roles, physiology of regulated genes, regulatory function, length and genome position, showing that these families have evolved homogeneously in prokaryotes, particularly in E.coli. This work describes a full characterization of the repertoire of regulatory interactions in a whole living cell. This repertoire should contribute to the interpretation of global gene expression profiles in both prokaryotes and eukaryotes.

  20. Measurements of translation initiation from all 64 codons in E. coli

    PubMed Central

    Hecht, Ariel; Glasgow, Jeff; Bawazer, Lukmaan A.; Munson, Matthew S.; Cochran, Jennifer R.

    2017-01-01

    Abstract Our understanding of translation underpins our capacity to engineer living systems. The canonical start codon (AUG) and a few near-cognates (GUG, UUG) are considered as the ‘start codons’ for translation initiation in Escherichia coli. Translation is typically not thought to initiate from the 61 remaining codons. Here, we quantified translation initiation of green fluorescent protein and nanoluciferase in E. coli from all 64 triplet codons and across a range of DNA copy number. We detected initiation of protein synthesis above measurement background for 47 codons. Translation from non-canonical start codons ranged from 0.007 to 3% relative to translation from AUG. Translation from 17 non-AUG codons exceeded the highest reported rates of non-cognate codon recognition. Translation initiation from non-canonical start codons may contribute to the synthesis of peptides in both natural and synthetic biological systems. PMID:28334756

  1. mRNA-programmed translation pauses in the targeting of E. coli membrane proteins.

    PubMed

    Fluman, Nir; Navon, Sivan; Bibi, Eitan; Pilpel, Yitzhak

    2014-08-18

    In all living organisms, ribosomes translating membrane proteins are targeted to membrane translocons early in translation, by the ubiquitous signal recognition particle (SRP) system. In eukaryotes, the SRP Alu domain arrests translation elongation of membrane proteins until targeting is complete. Curiously, however, the Alu domain is lacking in most eubacteria. In this study, by analyzing genome-wide data on translation rates, we identified a potential compensatory mechanism in E. coli that serves to slow down the translation during membrane protein targeting. The underlying mechanism is likely programmed into the coding sequence, where Shine-Dalgarno-like elements trigger elongation pauses at strategic positions during the early stages of translation. We provide experimental evidence that slow translation during targeting and improves membrane protein production fidelity, as it correlates with better folding of overexpressed membrane proteins. Thus, slow elongation is important for membrane protein targeting in E. coli, which utilizes mechanisms different from the eukaryotic one to control the translation speed.

  2. Current pathogenic Escherichia coli foodborne outbreak cases and therapy development.

    PubMed

    Yang, Shih-Chun; Lin, Chih-Hung; Aljuffali, Ibrahim A; Fang, Jia-You

    2017-08-01

    Food contamination by pathogenic microorganisms has been a serious public health problem and a cause of huge economic losses worldwide. Foodborne pathogenic Escherichia coli (E. coli) contamination, such as that with E. coli O157 and O104, is very common, even in developed countries. Bacterial contamination may occur during any of the steps in the farm-to-table continuum from environmental, animal, or human sources and cause foodborne illness. To understand the causes of the foodborne outbreaks by E. coli and food-contamination prevention measures, we collected and investigated the past 10 years' worldwide reports of foodborne E. coli contamination cases. In the first half of this review article, we introduce the infection and symptoms of five major foodborne diarrheagenic E. coli pathotypes: enteropathogenic E. coli (EPEC), Shiga toxin-producing E. coli/enterohemorrhagic E. coli (STEC/EHEC), Shigella/enteroinvasive E. coli (EIEC), enteroaggregative E. coli (EAEC), and enterotoxigenic E. coli (ETEC). In the second half of this review article, we introduce the foodborne outbreak cases caused by E. coli in natural foods and food products. Finally, we discuss current developments that can be applied to control and prevent bacterial food contamination.

  3. Diversity of CRISPR loci in Escherichia coli.

    PubMed

    Díez-Villaseñor, C; Almendros, C; García-Martínez, J; Mojica, F J M

    2010-05-01

    CRISPR (clustered regularly interspaced short palindromic repeats) and CAS (CRISPR-associated sequence) proteins are constituents of a novel genetic barrier that limits horizontal gene transfer in prokaryotes by means of an uncharacterized mechanism. The fundamental discovery of small RNAs as the guides of the defence apparatus arose as a result of Escherichia coli studies. However, a survey of the system diversity in this species in order to further contribute to the understanding of the CRISPR mode of action has not yet been performed. Here we describe two CRISPR/CAS systems found in E. coli, following the analysis of 100 strains representative of the species' diversity. Our results substantiate different levels of activity between loci of both CRISPR types, as well as different target preferences and CRISPR relevances for particular groups of strains. Interestingly, the data suggest that the degeneration of one CRISPR/CAS system in E. coli ancestors could have been brought about by self-interference.

  4. Thymineless death in Escherichia coli: strain specificity.

    PubMed

    Cummings, D J; Mondale, L

    1967-06-01

    Thymineless death of various ultraviolet (UV)-sensitive strains of Escherichia coli B and K-12 was investigated. It was found that E. coli B, B(s-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.

  5. 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

  6. 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.

  7. Escherichia coli O 27 in adult diarrhoea.

    PubMed Central

    Hobbs, B. C.; Rowe, B.; Kendall, M.; Turnbull, P. C.; Ghosh, A. C.

    1976-01-01

    Escherichia coli O 27 H 7 was found in 16 stool samples submitted during a Caribbean cruise (Cruise Z) by 29 patients reporting with diarrhoea. A retrospective search revealed E. coli O 27 H 7 in 11 of 20 and 2 of 14 stool cultures from patients on two previous cruises (Y and X respectively) and in a culture from fresh cream (Cruise Y). The repeated occurrence of E. coli O 27 H 7 in the absence of any other apparent cause suggested that this serotype may have been responsible for the diarrhoea. The results of pathogenicity tests suggested that this strain elaborated heat-stable (ST) enterotoxin. The possibility that food may have been the vector is discussed. PMID:794406

  8. Frequency-Dependent Escherichia coli Chemotaxis Behavior

    NASA Astrophysics Data System (ADS)

    Zhu, Xuejun; Si, Guangwei; Deng, Nianpei; Ouyang, Qi; Wu, Tailin; He, Zhuoran; Jiang, Lili; Luo, Chunxiong; Tu, Yuhai

    2012-03-01

    We study Escherichia coli chemotaxis behavior in environments with spatially and temporally varying attractant sources by developing a unique microfluidic system. Our measurements reveal a frequency-dependent chemotaxis behavior. At low frequency, the E. coli population oscillates in synchrony with the attractant. In contrast, in fast-changing environments, the population response becomes smaller and out of phase with the attractant waveform. These observations are inconsistent with the well-known Keller-Segel chemotaxis equation. A new continuum model is proposed to describe the population level behavior of E. coli chemotaxis based on the underlying pathway dynamics. With the inclusion of a finite adaptation time and an attractant consumption rate, our model successfully explains the microfluidic experiments at different stimulus frequencies.

  9. Production of curcuminoids in engineered Escherichia coli.

    PubMed

    Kim, Eun Ji; Cha, Mi Na; Kim, Bog-Gyu; Ahn, Joong-Hoon

    2017-03-09

    Curcumin, a hydrophobic polyphenol derived from the rhizome of the herb Curcuma longa, possesses diverse pharmacological properties including anti-inflammatory, antioxidant, antiproliferative and antiangiogenic activity. Two curcuminoids (dicinnamoylmethane and bisdemethoxycurcumin) were synthesized from glucose in Escherichia coli. PAL (phenylalanine ammonia lyase) or TAL (tyrosine ammonia lyase), along with Os4CL (p-coumaroyl-CoA ligase) and CUS (curcumin synthase), were introduced in to E. coli, and each strain produced dicinnamoylmethane or bisdemethoxycurcumin, respectively. In order to increase the production of curcuminoids in E. coli, the shikimic acid biosynthesis pathway which increases the substrates for curcuminoid biosynthesis, was engineered. Using engineered strains, the production of bisdemethoxycurcumin increased from 0.32 to 4.63 mg/L, and that of dicinnamoylmethane from 1.24 mg/L and 6.95 mg/L.

  10. Prodigiosin - A Multifaceted Escherichia coli Antimicrobial Agent

    PubMed Central

    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

  11. Intramammary challenge with Escherichia coli following immunization with a curli-producing Escherichia coli.

    PubMed

    Todhunter, D A; Smith, K L; Hogan, J S; Nelson, L

    1991-03-01

    Holstein and Jersey cattle were immunized with a curli-producing strain of Escherichia coli (pCRL65/A012) or a noncurli-producing strain (pUC18/HB101) to determine differences in resistance to establishment of experimental intramammary infection. Cows (n = 6 per group) were immunized at 14 d prior to drying off, 7 d of involution, and at calving with 3 x 10(10) E. coli in Freund's Incomplete Adjuvant. At 30 d of lactation, one mammary quarter of each cow was infused with a wild strain of E. coli (727). Escherichia coli 727 was isolated from a naturally occurring intramammary infection and produced curli. All challenged quarters became infected, and all cows developed acute clinical mastitis. Geometric mean duration of intramammary infections was 6 d for both immunization groups. All infections were spontaneously eliminated within 10 d. No differences occurred between immunization groups in blood selenium and glutathione peroxidase activity, plasma selenium, number of E. coli 727 isolated from secretion after challenge, rectal temperature and SCC response, clinical status of mammary quarters, or DMI. Reduction in milk production after challenge was greater for cows immunized with E. coli pCRL65/A012. Immunization of dairy cattle with a curli-producing strain of E. coli did not protect against experimental intramammary challenge during lactation.

  12. Persistent colonization of sheep by Escherichia coli O157:H7 and other E. coli pathotypes.

    PubMed

    Cornick, N A; Booher, S L; Casey, T A; Moon, H W

    2000-11-01

    Shiga toxin-producing Escherichia coli (STEC) is an important cause of food-borne illness in humans. Ruminants appear to be more frequently colonized by STEC than are other animals, but the reason(s) for this is unknown. We compared the frequency, magnitude, duration, and transmissibility of colonization of sheep by E. coli O157:H7 to that by other pathotypes of E. coli. Young adult sheep were simultaneously inoculated with a cocktail consisting of two strains of E. coli O157:H7, two strains of enterotoxigenic E. coli (ETEC), and one strain of enteropathogenic E. coli. Both STEC strains and ETEC 2041 were given at either 10(7) or 10(10) CFU/strain/animal. The other strains were given only at 10(10) CFU/strain. We found no consistent differences among pathotypes in the frequency, magnitude, and transmissibility of colonization. However, the STEC strains tended to persist to 2 weeks and 2 months postinoculation more frequently than did the other pathotypes. The tendency for persistence of the STEC strains was apparent following an inoculation dose of either 10(7) or 10(10) CFU. One of the ETEC strains also persisted when inoculated at 10(10) CFU. However, in contrast to the STEC strains, it did not persist when inoculated at 10(7) CFU. These results support the hypothesis that STEC is better adapted to persist in the alimentary tracts of sheep than are other pathotypes of E. coli.

  13. Melanosis coli in patients with colon cancer

    PubMed Central

    Biernacka-Wawrzonek, Dorota; Stępka, Michał; Tomaszewska, Alicja; Ehrmann-Jóśko, Agnieszka; Chojnowska, Natalia; Muszyński, Jacek

    2016-01-01

    Introduction Melanosis coli is a benign lesion affecting the mucosa of the large intestine. There is a relationship between the presence of melanosis and anthraquinone laxative use. Melanosis coli is also observed in patients with colon cancer, but there is doubt whether these two conditions are related. Aim To analyze the correlation between melanosis and colon cancer. Material and methods We analyzed retrospectively 436 patients undergoing colon cancer surgery. There were 246 women and 190 men. Patients were divided into three age groups: under 50 years, between 51 and 65 years, and over 66 years. We analyzed sections of the cancer and intestinal mucosa from the tumor’s proximal (2–5 cm) and distal (8–10 cm) zone. Results Melanosis coli was present in 52 patients, which represents 11.9% of patients with colon cancer. More often it was present in women. The most common location of melanosis and colon cancer was the terminal part of the large intestine. In patients below 50 years of age in both sexes melanosis coli did not occur. In men, melanosis was more common in the age group over 66 years. Intensity of pigmentation was higher in the tumor’s distal zone. Conclusions The incidence of melanosis coli increases with age, similar to that of colon cancer. Melanosis was not present inside tumors, in almost half of the cases it was not present in the proximal zone, and the degree of pigmentation increased in distal zone. The cause-effect relationship between melanosis coli and colon cancer remains uncertain. PMID:28337232

  14. Inactivation of Escherichia coli by citral.

    PubMed

    Somolinos, M; García, D; Condón, S; Mackey, B; Pagán, R

    2010-06-01

    The aim was to evaluate (i) the resistance of Escherichia coli BJ4 to citral in a buffer system as a function of citral concentration, treatment medium pH, storage time and initial inoculum size, (ii) the role of the sigma factor RpoS on citral resistance of E. coli, (iii) the role of the cell envelope damage in the mechanism of microbial inactivation by citral and (iiii) possible synergistic effects of mild heat treatment and pulsed electric fields (PEF) treatment combined with citral. The initial inoculum size greatly affected the efficacy of citral against E. coli cells. Exposure to 200 microl l(-1) of citral at pH 4.0 for 24 h at 20 degrees C caused the inactivation of more than 5 log(10) cycles of cells starting at an inoculum size of 10(6) or 10(7) CFU ml(-1), whereas increasing the cell concentration to 10(9) CFU ml(-1) caused <1 log(10) cycle of inactivation. Escherichia coli showed higher resistance to citral at pH 4.0 than pH 7.0. The rpoS null mutant strain E. coli BJ4L1 was less resistant to citral than the wild-type strain. Occurrence of sublethal injury to both the cytoplasmic and outer membranes was demonstrated by adding sodium chloride or bile salts to the recovery media. The majority of sublethally injured cells by citral required energy and lipid synthesis for repair. A strongly synergistic lethal effect was shown by mild heat treatment combined with citral but the presence of citral during the application of a PEF treatment did not show any advantage. This work confirms that cell envelope damage is an important event in citral inactivation of bacteria, and it describes the key factors on the inactivation of E. coli cells by citral. Knowledge about the mechanism of microbial inactivation by citral helps establish successful combined preservation treatments.

  15. Detection of E. coli O157:H7 from ground beef using Fourier transform infrared (FT-IR) spectroscopy and chemometrics.

    PubMed

    Davis, Reeta; Irudayaraj, Joseph; Reuhs, Bradley L; Mauer, Lisa J

    2010-08-01

    FT-IR spectroscopy methods for detection, differentiation, and quantification of E. coli O157:H7 strains separated from ground beef were developed. Filtration and immunomagnetic separation (IMS) were used to extract live and dead E. coli O157:H7 cells from contaminated ground beef prior to spectral acquisition. Spectra were analyzed using chemometric techniques in OPUS, TQ Analyst, and WinDAS software programs. Standard plate counts were used for development and validation of spectral analyses. The detection limit based on a selectivity value using the OPUS ident test was 10(5) CFU/g for both Filtration-FT-IR and IMS-FT-IR methods. Experiments using ground beef inoculated with fewer cells (10(1) to 10(2) CFU/g) reached the detection limit at 6 h incubation. Partial least squares (PLS) models with cross validation were used to establish relationships between plate counts and FT-IR spectra. Better PLS predictions were obtained for quantifying live E. coli O157:H7 strains (R(2)> or = 0.9955, RMSEE < or = 0.17, RPD > or = 14) and different ratios of live and dead E. coli O157:H7 cells (R(2)= 0.9945, RMSEE = 2.75, RPD = 13.43) from ground beef using Filtration-FT-IR than IMS-FT-IR methods. Discriminant analysis and canonical variate analysis (CVA) of the spectra differentiated various strains of E. coli O157:H7 from an apathogenic control strain. CVA also separated spectra of 100% dead cells separated from ground beef from spectra of 0.5% live cells in the presence of 99.5% dead cells of E. coli O157:H7. These combined separation and FT-IR methods could be useful for rapid detection and differentiation of pathogens in complex foods.

  16. Novel Selective Detection Method of Tumor Angiogenesis Factors Using Living Nano-Robots.

    PubMed

    Al-Fandi, Mohamed; Alshraiedeh, Nida; Owies, Rami; Alshdaifat, Hala; Al-Mahaseneh, Omamah; Al-Tall, Khadijah; Alawneh, Rawan

    2017-07-14

    This paper reports a novel self-detection method for tumor cells using living nano-robots. These living robots are a nonpathogenic strain of E. coli bacteria equipped with naturally synthesized bio-nano-sensory systems that have an affinity to VEGF, an angiogenic factor overly-expressed by cancer cells. The VEGF-affinity/chemotaxis was assessed using several assays including the capillary chemotaxis assay, chemotaxis assay on soft agar, and chemotaxis assay on solid agar. In addition, a microfluidic device was developed to possibly discover tumor cells through the overexpressed vascular endothelial growth factor (VEGF). Various experiments to study the sensing characteristic of the nano-robots presented a strong response toward the VEGF. Thus, a new paradigm of selective targeting therapies for cancer can be advanced using swimming E. coli as self-navigator miniaturized robots as well as drug-delivery vehicles.

  17. Label-Free Detection of Single Living Bacteria via Electrochemical Collision Event

    PubMed Central

    Lee, Ji Young; Kim, Byung-Kwon; Kang, Mijeong; Park, Jun Hui

    2016-01-01

    We detected single living bacterial cells on ultramicroelectrode (UME) using a single-particle collision method and optical microscopic methods. The number of collision events involving the bacterial cells indicated in current-time (i-t) curves corresponds to the number of bacterial cells (i.e., Escherichia coli) on the UME surface, as observed visually. Simulations were performed to determine the theoretical current response (75 pA) and frequency (0.47 pM−1 s−1) of single Escherichia coli collisions. The experimental current response (83 pA) and frequency (0.26 pM−1 s−1) were on the same order of magnitude as the theoretical values. This single-particle collision approach facilitates detecting living bacteria and determining their concentration in solution and could be widely applied to studying other bacteria and biomolecules. PMID:27435527

  18. Novel Selective Detection Method of Tumor Angiogenesis Factors Using Living Nano-Robots

    PubMed Central

    Alshraiedeh, Nida; Owies, Rami; Alshdaifat, Hala; Al-Mahaseneh, Omamah; Al-Tall, Khadijah; Alawneh, Rawan

    2017-01-01

    This paper reports a novel self-detection method for tumor cells using living nano-robots. These living robots are a nonpathogenic strain of E. coli bacteria equipped with naturally synthesized bio-nano-sensory systems that have an affinity to VEGF, an angiogenic factor overly-expressed by cancer cells. The VEGF-affinity/chemotaxis was assessed using several assays including the capillary chemotaxis assay, chemotaxis assay on soft agar, and chemotaxis assay on solid agar. In addition, a microfluidic device was developed to possibly discover tumor cells through the overexpressed vascular endothelial growth factor (VEGF). Various experiments to study the sensing characteristic of the nano-robots presented a strong response toward the VEGF. Thus, a new paradigm of selective targeting therapies for cancer can be advanced using swimming E. coli as self-navigator miniaturized robots as well as drug-delivery vehicles. PMID:28708066

  19. 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

  20. Escherichia coli field contamination of pecan nuts.

    PubMed

    Marcus, K A; Amling, H J

    1973-09-01

    More pecan samples collected from grazed orchards were contaminated with Escherichia coli than were samples from nongrazed orchards. No differences in frequency of contamination between mechanically and manually harvested nuts occurred. Nutmeats from whole uncracked pecans that were soaked for 24 h in a lactose broth solution containing E. coli did not become contaminated. Twentyfour percent of the whole pecans soaked in water for 48 h to simulate standing in a rain puddle developed openings along shell suture lines which did not completely close when the nuts were redried.

  1. 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.

  2. Impact of homologous and non-homologous recombination in the genomic evolution of Escherichia coli.

    PubMed

    Didelot, Xavier; Méric, Guillaume; Falush, Daniel; Darling, Aaron E

    2012-06-19

    Escherichia coli is an important species of bacteria that can live as a harmless inhabitant of the guts of many animals, as a pathogen causing life-threatening conditions or freely in the non-host environment. This diversity of lifestyles has made it a particular focus of interest for studies of genetic variation, mainly with the aim to understand how a commensal can become a deadly pathogen. Many whole genomes of E. coli have been fully sequenced in the past few years, which offer helpful data to help understand how this important species evolved. We compared 27 whole genomes encompassing four phylogroups of Escherichia coli (A, B1, B2 and E). From the core-genome we established the clonal relationships between the isolates as well as the role played by homologous recombination during their evolution from a common ancestor. We found strong evidence for sexual isolation between three lineages (A+B1, B2, E), which could be explained by the ecological structuring of E. coli and may represent on-going speciation. We identified three hotspots of homologous recombination, one of which had not been previously described and contains the aroC gene, involved in the essential shikimate metabolic pathway. We also described the role played by non-homologous recombination in the pan-genome, and showed that this process was highly heterogeneous. Our analyses revealed in particular that the genomes of three enterohaemorrhagic (EHEC) strains within phylogroup B1 have converged from originally separate backgrounds as a result of both homologous and non-homologous recombination. Recombination is an important force shaping the genomic evolution and diversification of E. coli, both by replacing fragments of genes with an homologous sequence and also by introducing new genes. In this study, several non-random patterns of these events were identified which correlated with important changes in the lifestyle of the bacteria, and therefore provide additional evidence to explain the

  3. Antimicrobial resistance in Escherichia coli isolates from raccoons (Procyon lotor) in Southern Ontario, Canada.

    PubMed

    Jardine, Claire M; Janecko, Nicol; Allan, Mike; Boerlin, Patrick; Chalmers, Gabhan; Kozak, Gosia; McEwen, Scott A; Reid-Smith, Richard J

    2012-06-01

    We conducted a cross-sectional study to determine the prevalence of antimicrobial resistance (AMR) in fecal Escherichia coli isolates from raccoons (Procyon lotor) living in Ontario, Canada. From June to October 2007, we trapped raccoons in three areas: one primarily urban site around Niagara, one primarily rural site north of Guelph, and one at the Toronto Zoo. In addition, we conducted a longitudinal study at the Toronto Zoo site to investigate the temporal dynamics of fecal E. coli and AMR in raccoons. Reduced susceptibility to ≥1 antimicrobial agent was detected in E. coli isolates from 19% of 16 raccoons at the urban site, 17% of 29 raccoons from the rural site, and 42% of 130 samples collected from 59 raccoons at the zoo site. Raccoons from the zoo site were significantly more likely to shed E. coli with reduced susceptibility to ≥1 antimicrobial agent than animals from the rural site (odds ratio [OR], 3.41; 95% confidence interval [CI], 1.17 to 12.09; P = 0.02). Resistance to expanded-spectrum cephalosporins (and the associated bla(CMY-2) gene) was detected in two animals from the zoo site and one animal from the rural site. Serotyping and pulsed-field gel electrophoresis analysis show that raccoons on the zoo grounds harbor a diverse assemblage of E. coli, with rapid bacterial turnover within individuals over time. Our study indicates that raccoons may shed resistant bacteria of public health significance and that raccoons have the potential to disseminate these bacteria throughout their environment.

  4. Antimicrobial Resistance in Escherichia coli Isolates from Raccoons (Procyon lotor) in Southern Ontario, Canada

    PubMed Central

    Janecko, Nicol; Allan, Mike; Boerlin, Patrick; Chalmers, Gabhan; Kozak, Gosia; McEwen, Scott A.; Reid-Smith, Richard J.

    2012-01-01

    We conducted a cross-sectional study to determine the prevalence of antimicrobial resistance (AMR) in fecal Escherichia coli isolates from raccoons (Procyon lotor) living in Ontario, Canada. From June to October 2007, we trapped raccoons in three areas: one primarily urban site around Niagara, one primarily rural site north of Guelph, and one at the Toronto Zoo. In addition, we conducted a longitudinal study at the Toronto Zoo site to investigate the temporal dynamics of fecal E. coli and AMR in raccoons. Reduced susceptibility to ≥1 antimicrobial agent was detected in E. coli isolates from 19% of 16 raccoons at the urban site, 17% of 29 raccoons from the rural site, and 42% of 130 samples collected from 59 raccoons at the zoo site. Raccoons from the zoo site were significantly more likely to shed E. coli with reduced susceptibility to ≥1 antimicrobial agent than animals from the rural site (odds ratio [OR], 3.41; 95% confidence interval [CI], 1.17 to 12.09; P = 0.02). Resistance to expanded-spectrum cephalosporins (and the associated blaCMY-2 gene) was detected in two animals from the zoo site and one animal from the rural site. Serotyping and pulsed-field gel electrophoresis analysis show that raccoons on the zoo grounds harbor a diverse assemblage of E. coli, with rapid bacterial turnover within individuals over time. Our study indicates that raccoons may shed resistant bacteria of public health significance and that raccoons have the potential to disseminate these bacteria throughout their environment. PMID:22447599

  5. Prediction of transcriptional regulatory sites in the complete genome sequence of Escherichia coli K-12.

    PubMed

    Thieffry, D; Salgado, H; Huerta, A M; Collado-Vides, J

    1998-06-01

    As one of the best-characterized free-living organisms, Escherichia coli and its recently completed genomic sequence offer a special opportunity to exploit systematically the variety of regulatory data available in the literature in order to make a comprehensive set of regulatory predictions in the whole genome. The complete genome sequence of E.coli was analyzed for the binding of transcriptional regulators upstream of coding sequences. The biological information contained in RegulonDB (Huerta, A.M. et al., Nucleic Acids Res.,26,55-60, 1998) for 56 different transcriptional proteins was the support to implement a stringent strategy combining string search and weight matrices. We estimate that our search included representatives of 15-25% of the total number of regulatory binding proteins in E.coli. This search was performed on the set of 4288 putative regulatory regions, each 450 bp long. Within the regions with predicted sites, 89% are regulated by one protein and 81% involve only one site. These numbers are reasonably consistent with the distribution of experimental regulatory sites. Regulatory sites are found in 603 regions corresponding to 16% of operon regions and 10% of intra-operonic regions. Additional evidence gives stronger support to some of these predictions, including the position of the site, biological consistency with the function of the downstream gene, as well as genetic evidence for the regulatory interaction. The predictions described here were incorporated into the map presented in the paper describing the complete E.coli genome (Blattner,F.R. et al., Science, 277, 1453-1461, 1997). The complete set of predictions in GenBank format is available at the url: http://www. cifn.unam.mx/Computational_Biology/E.coli-predictions ecoli-reg@cifn.unam.mx, collado@cifn.unam.mx

  6. Antibiotic resistance and virulence genes of extraintestinal pathogenic Escherichia coli from tropical estuary, South India.

    PubMed

    Sukumaran, Divya; Mohamed Hatha, Abdulla A

    2015-05-18

    Escherichia coli strains can cause a variety of intestinal and extraintestinal diseases. Extraintestinal pathogenic E. coli (ExPEC) strains have the ability to cause severe extraintestinal infections. Multidrug resistance among ExPEC could complicate human infections. Escherichia coli strains were isolated during the period of January 2010 to December 2012 from five different stations set at Cochin estuary. Susceptibility testing was determined by the disk-diffusion method using nine different antimicrobial agents. A total of 155 strains of Escherichia coli were screened for the presence of virulence factor genes including papAH, papC, sfa/focDE, iutA,and kpsMT II associated with ExPEC. Among the 155 E. coli isolates, 26 (16.77%), carried two or more virulence genes typical of ExPEC. Furthermore, 19.23% of the ExPEC isolates with multidrug resistance were identified to belong to phylogenetic groups B2 and D. Statistically significant association of iutA gene in ExPEC was found with papC (p < 0.001) and kpsMT II (p < 0.001) genes. ExPEC isolates were mainly resistant to ampicillin (23.07%), tetracycline (19.23%), co-trimoxazole (15.38%), and cefotaxime (15.38%). The adhesion genes papAH and sfa/focDE were positively associated with resistance to gentamicin, chloramphenicol, and cefotaxime (p < 0.05). Co-occurrence of virulence factor genes with antibiotic resistance among ExPEC poses considerable threat to those who use this aquatic system for a living and for recreation.

  7. Ciliates rapidly enhance the frequency of conjugation between Escherichia coli strains through bacterial accumulation in vesicles.

    PubMed

    Matsuo, Junji; Oguri, Satoshi; Nakamura, Shinji; Hanawa, Tomoko; Fukumoto, Tatsuya; Hayashi, Yasuhiro; Kawaguchi, Kouhei; Mizutani, Yoshihiko; Yao, Takashi; Akizawa, Kouzi; Suzuki, Haruki; Simizu, Chikara; Matsuno, Kazuhiko; Kamiya, Shigeru; Yamaguchi, Hiroyuki

    2010-10-01

    The mechanism underlying bacterial conjugation through protozoa was investigated. Kanamycin-resistant Escherichia coli SM10λ+ carrying pRT733 with TnphoA was used as donor bacteria and introduced by conjugation into ciprofloxacin-resistant E. coli clinical isolate recipient bacteria. Equal amounts of donor and recipient bacteria were mixed together in the presence or absence of protozoa (ciliates, free-living amoebae, myxamoebae) in Page's amoeba saline for 24 h. Transconjugants were selected with Luria broth agar containing kanamycin and ciprofloxacin. The frequency of conjugation was estimated as the number of transconjugants for each recipient. Conjugation frequency in the presence of ciliates was estimated to be approximately 10⁻⁶, but in the absence of ciliates, or in the presence of other protozoa, it was approximately 10⁻⁸. Conjugation also occurred in culture of ciliates at least 2 h after incubation. Successful conjugation was confirmed by the polymerase chain reaction. Addition of cycloheximide or latrunculin B resulted in suppression of conjugation. Heat killing the ciliates or bacteria had no effect on conjugation frequency. Co-localization of green fluorescent protein-expressing E. coli and PKH-67-vital-stained E. coli was observed in the same ciliate vesicles, suggesting that both donor and recipient bacteria had accumulated in the same vesicle. In this study, the conjugation frequency of bacteria was found to be significantly higher in vesicles purified from ciliates than those in culture suspension. We conclude that ciliates rapidly enhance the conjugation of E. coli strains through bacterial accumulation in vesicles.

  8. Prevalence of Virulence Determinants and Antimicrobial Resistance among Commensal Escherichia coli Derived from Dairy and Beef Cattle

    PubMed Central

    Bok, Ewa; Mazurek, Justyna; Stosik, Michał; Wojciech, Magdalena; Baldy-Chudzik, Katarzyna

    2015-01-01

    Cattle is a reservoir of potentially pathogenic E. coli, bacteria that can represent a significant threat to public health, hence it is crucial to monitor the prevalence of the genetic determinants of virulence and antimicrobial resistance among the E. coli population. The aim of this study was the analysis of the phylogenetic structure, distribution of virulence factors (VFs) and prevalence of antimicrobial resistance among E. coli isolated from two groups of healthy cattle: 50 cows housed in the conventional barn (147 isolates) and 42 cows living on the ecological pasture (118 isolates). The phylogenetic analysis, identification of VFs and antimicrobial resistance genes were based on either multiplex or simplex PCR. The antimicrobial susceptibilities of E. coli were examined using the broth microdilution method. Two statistical approaches were used to analyse the results obtained for two groups of cattle. The relations between the dependent (VFs profiles, antibiotics) and the independent variables were described using the two models. The mixed logit model was used to characterise the prevalence of the analysed factors in the sets of isolates. The univariate logistic regression model was used to characterise the prevalence of these factors in particular animals. Given each model, the odds ratio (OR) and the 95% confidence interval for the population were estimated. The phylogroup B1 was predominant among isolates from beef cattle, while the phylogroups A, B1 and D occurred with equal frequency among isolates from dairy cattle. The frequency of VFs-positive isolates was significantly higher among isolates from beef cattle. E. coli from dairy cattle revealed significantly higher resistance to antibiotics. Some of the tested resistance genes were present among isolates from dairy cattle. Our study showed that the habitat and diet may affect the genetic diversity of commensal E. coli in the cattle. The results suggest that the ecological pasture habitat is related to

  9. Intracellular colon cancer-associated Escherichia coli promote protumoral activities of human macrophages by inducing sustained COX-2 expression.

    PubMed

    Raisch, Jennifer; Rolhion, Nathalie; Dubois, Anaëlle; Darfeuille-Michaud, Arlette; Bringer, Marie-Agnès

    2015-03-01

    Intestinal dysbiosis has been reported in patients with colorectal cancer, and there is a high prevalence of Escherichia coli belonging to B2 phylogroup and producing a genotoxin, termed colibactin. Macrophages are one of the predominant tumor-infiltrating immune cells supporting key processes in tumor progression by producing protumoral factors such as cyclooxygenase-2 (COX-2). Here, we investigated whether B2 E. coli colonizing colon tumors could influence protumoral activities of macrophages. In contrast to commensal or nonpathogenic E. coli strains that were efficiently and rapidly degraded by macrophages at 24 h after infection, colon cancer-associated E. coli were able to resist killing by human THP-1 macrophages, to replicate intracellularly, and to persist inside host cells until at least 72 h after infection. Significant increases in COX-2 expression were observed in macrophages infected with colon cancer E. coli compared with macrophages infected with commensal and nonpathogenic E. coli strains or uninfected cells at 72 h after infection. Induction of COX-2 expression required live bacteria and was not due to colibactin production, as similar COX-2 levels were observed in macrophages infected with the wild-type colon cancer-associated E. coli 11G5 strain or a clbQ mutant unable to produce colibactin. Treatment of macrophages with ofloxacin, an antibiotic with intracellular tropism, efficiently decreased the number of intracellular bacteria and suppressed bacteria-induced COX-2 expression. This study provides new insights into the understanding of how tumor- infiltrating bacteria could influence cancer progression through their interaction with immune cells. Manipulation of microbes associated with tumors could have a deep influence on the secretion of protumoral molecules by infiltrating macrophages.

  10. Escherichia coli Attenuation by Fe Electrocoagulation in Synthetic Bengal Groundwater: Effect of pH and Natural Organic Matter.

    PubMed

    Delaire, Caroline; van Genuchten, Case M; Nelson, Kara L; Amrose, Susan E; Gadgil, Ashok J

    2015-08-18

    Technologies addressing both arsenic and microbial contamination of Bengal groundwater are needed. Fe electrocoagulation (Fe-EC), a simple process relying on the dissolution of an Fe(0) anode to produce Fe(III) precipitates, has been shown to efficiently remove arsenic from groundwater at low cost. We investigated Escherichia coli (E. coli) attenuation by Fe-EC in synthetic Bengal groundwater as a function of Fe dosage rate, total Fe dosed, pH, and presence of natural organic matter (NOM). A 2.5 mM Fe dosage simultaneously achieved over 4-log E. coli attenuation and arsenic removal from 450 to below 10 μg/L. E. coli reduction was significantly enhanced at pH 6.6 compared to pH 7.5, which we linked to the decreased rate of Fe(II) oxidation at lower pH. 3 mg/L-C of NOM (Suwanee River fulvic acid) did not significantly affect E. coli attenuation. Live-dead staining and comparisons of Fe-EC with chemical coagulation controls showed that the primary mechanism of E. coli attenuation is physical removal with Fe(III) precipitates, with inactivation likely contributing as well at lower pH. Transmission electron microscopy showed that EC precipitates adhere to and bridge individual E. coli cells, resulting in large bacteria-Fe aggregates that can be removed by gravitational settling. Our results point to the promising ability of Fe-EC to treat arsenic and bacterial contamination simultaneously at low cost.

  11. Fate and Persistence of a Pathogenic NDM-1-Positive Escherichia coli Strain in Anaerobic and Aerobic Sludge Microcosms

    PubMed Central

    Mantilla-Calderon, David

    2017-01-01

    ABSTRACT The presence of emerging biological pollutants in treated wastewater effluents has gained attention due to increased interest in water reuse. To evaluate the effectiveness of the removal of such contaminants by the conventional wastewater treatment process, the fate and decay kinetics of NDM-1-positive Escherichia coli strain PI7 and its plasmid-encoded antibiotic resistance genes (ARGs) were assessed in microcosms of anaerobic and aerobic sludge. Results showed that E. coli PI7 decayed at a significantly lower rate under anaerobic conditions. Approximate half-lives were 32.4 ± 1.4 h and 5.9 ± 0.9 h in the anaerobic and aerobic microcosms, respectively. In the aerobic microcosms, after 72 h of operation, E. coli PI7 remained detectable, but no further decay was observed. Instead, 1 in every 10,000 E. coli cells was identified to be recalcitrant to decay and persist indefinitely in the sludge. ARGs associated with the E. coli PI7 strain were detected to have transferred to other native microorganisms in the sludge or were released to the liquid fraction upon host decay. Extracellular DNA quickly degraded in the liquid fraction of the aerobic sludge. In contrast, no DNA decay was detected in the anaerobic sludge water matrix throughout the 24-h sampling period. This study suggests an increased likelihood of environmental dispersion of ARGs associated with anaerobically treated wastewater effluents and highlights the potential importance of persister cells in the dissemination of E. coli in the environment during reuse events of treated wastewater. IMPORTANCE This study examines the decay kinetics of a pathogenic and antibiotic resistant strain of Escherichia coli in microcosms simulating biological treatment units of aerobic and anaerobic sludge. The results of this study point at a significantly prolonged persistence of the E. coli and the associated antibiotic resistance gene in the anaerobic sludge. However, horizontal transfer of the plasmid encoding

  12. Fate and Persistence of a Pathogenic NDM-1-Positive Escherichia coli Strain in Anaerobic and Aerobic Sludge Microcosms.

    PubMed

    Mantilla-Calderon, David; Hong, Pei-Ying

    2017-07-01

    The presence of emerging biological pollutants in treated wastewater effluents has gained attention due to increased interest in water reuse. To evaluate the effectiveness of the removal of such contaminants by the conventional wastewater treatment process, the fate and decay kinetics of NDM-1-positive Escherichia coli strain PI7 and its plasmid-encoded antibiotic resistance genes (ARGs) were assessed in microcosms of anaerobic and aerobic sludge. Results showed that E. coli PI7 decayed at a significantly lower rate under anaerobic conditions. Approximate half-lives were 32.4 ± 1.4 h and 5.9 ± 0.9 h in the anaerobic and aerobic microcosms, respectively. In the aerobic microcosms, after 72 h of operation, E. coli PI7 remained detectable, but no further decay was observed. Instead, 1 in every 10,000 E. coli cells was identified to be recalcitrant to decay and persist indefinitely in the sludge. ARGs associated with the E. coli PI7 strain were detected to have transferred to other native microorganisms in the sludge or were released to the liquid fraction upon host decay. Extracellular DNA quickly degraded in the liquid fraction of the aerobic sludge. In contrast, no DNA decay was detected in the anaerobic sludge water matrix throughout the 24-h sampling period. This study suggests an increased likelihood of environmental dispersion of ARGs associated with anaerobically treated wastewater effluents and highlights the potential importance of persister cells in the dissemination of E. coli in the environment during reuse events of treated wastewater.IMPORTANCE This study examines the decay kinetics of a pathogenic and antibiotic resistant strain of Escherichia coli in microcosms simulating biological treatment units of aerobic and anaerobic sludge. The results of this study point at a significantly prolonged persistence of the E. coli and the associated antibiotic resistance gene in the anaerobic sludge. However, horizontal transfer of the plasmid encoding the

  13. Creating living machines

    PubMed Central

    Kamm, Roger D.; Bashir, Rashid

    2015-01-01

    Development of increasingly complex integrated cellular systems will be a major challenge for the next decade and beyond, as we apply the knowledge gained from the sub-disciplines of tissue engineering, synthetic biology, micro-fabrication and nanotechnology, systems biology, and developmental biology. In this prospective, we describe the current state-of-the-art in the context of differentiating source cells from more primitive, pluripotent cells, and organizing these cells into populations of a single cell type to produce the components or building blocks of higher order systems and finally, combining multiple cell types, possibly in combination with scaffolds possessing specific physical or chemical properties, to produce greater functionality. As these “living machines” increase in capabilities, exhibit emergent behavior and potentially reveal the ability for self-assembly, self-repair, and even self-replication, questions arise regarding the ethical implications of this work. Future prospects as well as ways of addressing these complex ethical questions will be addressed. PMID:24006130

  14. Live Information Objects

    DTIC Science & Technology

    2011-06-01

    prevent  it.    Users  of  the  system  pulled  information  of  various  kinds  into  the  shared  scenario:  city   maps,  images,  data  from  databases...videos  from  real‐time  feeds  in  the  city   itself.  Working  together,  they  rapidly  solved  their  problem.    The  live  application  could...hold groups of other objects: a  city  object might contain building objects; a  helicopter squadron multiple helicopters, and so forth.   What about data

  15. Influence of Asellus aquaticus on Escherichia coli, Klebsiella pneumoniae, Campylobacter jejuni and naturally occurring heterotrophic bacteria in drinking water.

    PubMed

    Christensen, Sarah C B; Nissen, Erling; Arvin, Erik; Albrechtsen, Hans-Jørgen

    2012-10-15

    Water lice, Asellus aquaticus (isopoda), frequently occur in drinking water distribution systems where they are a nuisance to consumers and water utilities. Whether they are solely an aesthetic problem or also affect the microbial water quality is a matter of interest. We studied the influence of A. aquaticus on microbial water quality in non-chlorinated drinking water in controlled laboratory experiments. Pure cultures of the indicator organisms Escherichia coli and Klebsiella pneumoniae and the pathogen Campylobacter jejuni as well as naturally occurring heterotrophic drinking water bacteria (measured as heterotrophic plate counts, HPC) were investigated in microcosms at 7 °C, containing non-sterilised drinking water, drinking water sediment and A. aquaticus collected from a non-chlorinated ground water based drinking water supply system. Concentrations of E. coli, K. pneumoniae and C. jejuni decreased over time, following a first order decay with half lives of 5.3, 18.4 and 1.3 days, respectively. A. aquaticus did not affect survival of indicators and pathogens substantially whereas HPC were influenced by presence of dead A. aquaticus. Growth rates increased with an average of 48% for bacteria grown on R-2A agar and an average of 83% for bacteria grown on yeast extract agar when dead A. aquaticus were present compared to no and living A. aquaticus present. A. aquaticus associated E. coli, K. pneumoniae and C. jejuni were measured (up to 25 per living and 500 per dead A. aquaticus) and so were A. aquaticus associated heterotrophic bacteria (>1.8*10(4) CFU per living and >6*10(4) CFU per dead A. aquaticus). A. aquaticus did not serve as an optimised habitat that increased survival of indicators and pathogens, since A. aquaticus associated E. coli, K. pneumoniae and C. jejuni were only measured as long as the bacteria were also present in the water and sediment. Copyright © 2012 Elsevier Ltd. All rights reserved.

  16. Exact Law of Live Nature

    NASA Astrophysics Data System (ADS)

    Azbel', Mark Ya.

    Exact law of mortality dynamics in changing populations and environment is derived. The law is universal for all species, from single cell yeast to humans. It includes no characteristics of animal-environment interactions (metabolism etc.) which are a must for life. Such law is unique for live systems with their homeostatic self-adjustment to environment. Its universal dynamics for all animals, with their drastically different biology, evolutionary history, and complexity, is also unique for live systems — cf. different thermodynamics of liquids and glasses. The law which is valid for all live, and only live, systems is a life specific law of nature.

  17. Photonic Crystal Optical Tweezers with High Efficiency for Live Biological Samples and Viability Characterization

    NASA Astrophysics Data System (ADS)

    Jing, Peifeng; Wu, Jingda; Liu, Gary W.; Keeler, Ethan G.; Pun, Suzie H.; Lin, Lih Y.

    2016-01-01

    We propose and demonstrate a new optical trapping method for single cells that utilizes modulated light fields to trap a wide array of cell types, including mammalian, yeast, and Escherichia coli cells, on the surface of a two-dimensional photonic crystal. This method is capable of reducing the required light intensity, and thus minimizing the photothermal damage to living cells, thereby extending cell viability in optical trapping and cell manipulation applications. To this end, a thorough characterization of cell viability in optical trapping environments was performed. This study also demonstrates the technique using spatial light modulation in patterned manipulation of live cell arrays over a broad area.

  18. Photonic Crystal Optical Tweezers with High Efficiency for Live Biological Samples and Viability Characterization

    PubMed Central

    Jing, Peifeng; Wu, Jingda; Liu, Gary W.; Keeler, Ethan G.; Pun, Suzie H.; Lin, Lih Y.

    2016-01-01

    We propose and demonstrate a new optical trapping method for single cells that utilizes modulated light fields to trap a wide array of cell types, including mammalian, yeast, and Escherichia coli cells, on the surface of a two-dimensional photonic crystal. This method is capable of reducing the required light intensity, and thus minimizing the photothermal damage to living cells, thereby extending cell viability in optical trapping and cell manipulation applications. To this end, a thorough characterization of cell viability in optical trapping environments was performed. This study also demonstrates the technique using spatial light modulation in patterned manipulation of live cell arrays over a broad area. PMID:26814808

  19. Photonic Crystal Optical Tweezers with High Efficiency for Live Biological Samples and Viability Characterization.

    PubMed

    Jing, Peifeng; Wu, Jingda; Liu, Gary W; Keeler, Ethan G; Pun, Suzie H; Lin, Lih Y

    2016-01-27

    We propose and demonstrate a new optical trapping method for single cells that utilizes modulated light fields to trap a wide array of cell types, including mammalian, yeast, and Escherichia coli cells, on the surface of a two-dimensional photonic crystal. This method is capable of reducing the required light intensity, and thus minimizing the photothermal damage to living cells, thereby extending cell viability in optical trapping and cell manipulation applications. To this end, a thorough characterization of cell viability in optical trapping environments was performed. This study also demonstrates the technique using spatial light modulation in patterned manipulation of live cell arrays over a broad area.

  20. E. coli survival in waters: applicability of the Arrhenius equation

    USDA-ARS?s Scientific Manuscript database

    E. coli is an important microorganism indicator used to show the presence of pathogens and fecal contamination in waters. Knowing E. coli survival rates is important for assessing the severity of contamination that has occurred and making appropriate management evaluations. E. coli survival rates ...

  1. WGS accurately predicts antimicrobial resistance in Escherichia coli

    USDA-ARS?s Scientific Manuscript database

    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...

  2. 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

  3. 77 FR 9888 - Shiga Toxin-Producing Escherichia coli

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-21

    ... program for the six non-O157 STEC, as it already does for E. coli O157:H7. The Agency intended to begin... Food Safety and Inspection Service Shiga Toxin-Producing Escherichia coli in Certain Raw Beef Products... manufacturing trimmings for six non-O157 Shiga toxin-producing Escherichia coli (STEC) serogroups (O26, O45...

  4. Lives Worth Living: Religious Education and Social Movements

    ERIC Educational Resources Information Center

    Ayres, Jennifer R.

    2013-01-01

    When people of faith participate in movements for social change, how are their religious and moral identities formed, challenged, and transformed? Although they have explicit and tangible goals as they participate in advocacy, protest, and boycotts, religious social activists also, James Jasper argues, craft "lives worth living" (1997).…

  5. The power of living things: Living memorials as therapeutic landscapes

    Treesearch

    Heather L. McMillen; Lindsay K. Campbell; Erika S. Svendsen

    2017-01-01

    In response to the events of 11 September 2001 (9/11), many communities came together to create living memorials. Many living memorials were established near the crash sites, but others were created across the United States from urban to rural areas, with designs ranging from entire forests to single trees. They were created by surviving family members, supporters of...

  6. Lives Worth Living: Religious Education and Social Movements

    ERIC Educational Resources Information Center

    Ayres, Jennifer R.

    2013-01-01

    When people of faith participate in movements for social change, how are their religious and moral identities formed, challenged, and transformed? Although they have explicit and tangible goals as they participate in advocacy, protest, and boycotts, religious social activists also, James Jasper argues, craft "lives worth living" (1997).…

  7. Day-to-Day Dynamics of Commensal Escherichia coli in Zimbabwean Cows Evidence Temporal Fluctuations within a Host-Specific Population Structure.

    PubMed

    Massot, Méril; Couffignal, Camille; Clermont, Olivier; D'Humières, Camille; Chatel, Jérémie; Plault, Nicolas; Andremont, Antoine; Caron, Alexandre; Mentré, France; Denamur, Erick

    2017-07-01

    To get insights into the temporal pattern of commensal Escherichia coli populations, we sampled the feces of four healthy cows from the same herd in the Hwange District of Zimbabwe daily over 25 days. The cows had not received antibiotic treatment during the previous 3 months. We performed viable E. coli counts and characterized the 326 isolates originating from the 98 stool samples at a clonal level, screened them for stx and eae genes, and tested them for their antibiotic susceptibilities. We observed that E. coli counts and dominant clones were different among cows, and very few clones were shared. No clone was shared by three or four cows. Clone richness and evenness were not different between cows. Within each host, the variability in the E. coli count was evidenced between days, and no clone was found to be dominant during the entire sampling period, suggesting the existence of clonal interference. Dominant clones tended to persist longer than subdominant ones and were mainly from phylogenetic groups A and B1. Five E. coli clones were found to contain both the stx1 and stx2 genes, representing 6.3% of the studied isolates. All cows harbored at least one Shiga toxin-producing E. coli (STEC) strain. Resistance to tetracycline, penicillins, trimethoprim, and sulfonamides was rare and observed in three clones that were shed at low levels in two cows. This study highlights the fact that the commensal E. coli population, including the STEC population, is host specific, is highly dynamic over a short time frame, and rarely carries antibiotic resistance determinants in the absence of antibiotic treatment.IMPORTANCE The literature about the dynamics of commensal Escherichia coli populations is very scarce. Over 25 days, we followed the total E. coli counts daily and characterized the sampled clones in the feces of four cows from the same herd living in the Hwange District of Zimbabwe. This study deals with the day-to-day dynamics of both quantitative and qualitative

  8. Effect of spray Escherichia coli vaccine on the immunity of poultry.

    PubMed

    Fernandes Filho, Tobias; Fávaro, Celso; Ingberman, Max; Beirão, Breno C B; Inoue, Alberto; Gomes, Lúdio; Caron, Luiz Felipe

    2013-09-01

    immunoglobulins. The assessment of cellular dynamics by flow cytometry made it possible to elucidate the operation mechanism of the live E. coli vaccine.

  9. Beta-Lactamase Producing Escherichia coli Isolates in Imported and Locally Produced Chicken Meat from Ghana

    PubMed Central

    Rasmussen, Mette Marie; Opintan, Japheth A.; Frimodt-Møller, Niels; Styrishave, Bjarne

    2015-01-01

    The use of antibiotics in food animals is of public health concern, because resistant zoonotic pathogens can be transmitted to humans. Furthermore, global trade with food may rapidly spread multi-resistant pathogens between countries and even continents. The purpose of the study was to investigate whether imported chicken meat and meat from locally reared chicken are potential sources for human exposure to multi resistant Escherichia coli isolates. 188 samples from imported and locally produced chicken meat were sampled and analyzed. 153 bacteria isolates were successfully cultured and identified as E. coli using MALDI-ToF. Of these 109 isolates were from meat whereas the remaining 44 were isolated from the cloaca of locally reared live chickens. Antimicrobial susceptibility test was done on the identified E. coli isolates. Additionally, beta-lactamases production (ESBL and/or AmpC) were phenotypically confirmed on all isolates showing resistance to cefpodoxime. Beta-lactamase producing (BLP) E. coli meat isolates were further genotyped. Antimicrobial resistance to four antibiotic markers with highest resistance was detected more frequently in isolates from local chickens compared to imported chickens (tetracycline 88.9% vs. 57.5%, sulphonamide 75.0% vs. 46.6%, ampicillin 69.4% vs. 61.6% and trimethoprim 66.7% vs. 38.4%). Beta-lactamase production was found in 29 E. coli meat isolates, with 56.9% of them being multiple drug resistant (≥ 3). The predominant phylogroup identified was B1 followed by A and D, with similar distribution among the isolates from meat of locally reared chickens and imported chickens. Beta-lactamase producing genotype blaCTX-M-15 (50%; 10/20) was the most frequently drug resistant gene detected. More BLP E. coli isolates were found in imported chicken meat compared to locally reared chickens, demonstrating that these isolates may be spreading through food trade. In conclusion, both imported and locally produced chicken meats are potential

  10. Beta-Lactamase Producing Escherichia coli Isolates in Imported and Locally Produced Chicken Meat from Ghana.

    PubMed

    Rasmussen, Mette Marie; Opintan, Japheth A; Frimodt-Møller, Niels; Styrishave, Bjarne

    2015-01-01

    The use of antibiotics in food animals is of public health concern, because resistant zoonotic pathogens can be transmitted to humans. Furthermore, global trade with food may rapidly spread multi-resistant pathogens between countries and even continents. The purpose of the study was to investigate whether imported chicken meat and meat from locally reared chicken are potential sources for human exposure to multi resistant Escherichia coli isolates. 188 samples from imported and locally produced chicken meat were sampled and analyzed. 153 bacteria isolates were successfully cultured and identified as E. coli using MALDI-ToF. Of these 109 isolates were from meat whereas the remaining 44 were isolated from the cloaca of locally reared live chickens. Antimicrobial susceptibility test was done on the identified E. coli isolates. Additionally, beta-lactamases production (ESBL and/or AmpC) were phenotypically confirmed on all isolates showing resistance to cefpodoxime. Beta-lactamase producing (BLP) E. coli meat isolates were further genotyped. Antimicrobial resistance to four antibiotic markers with highest resistance was detected more frequently in isolates from local chickens compared to imported chickens (tetracycline 88.9% vs. 57.5%, sulphonamide 75.0% vs. 46.6%, ampicillin 69.4% vs. 61.6% and trimethoprim 66.7% vs. 38.4%). Beta-lactamase production was found in 29 E. coli meat isolates, with 56.9% of them being multiple drug resistant (≥ 3). The predominant phylogroup identified was B1 followed by A and D, with similar distribution among the isolates from meat of locally reared chickens and imported chickens. Beta-lactamase producing genotype blaCTX-M-15 (50%; 10/20) was the most frequently drug resistant gene detected. More BLP E. coli isolates were found in imported chicken meat compared to locally reared chickens, demonstrating that these isolates may be spreading through food trade. In conclusion, both imported and locally produced chicken meats are potential

  11. Diffusion properties of single FoF1-ATP synthases in a living bacterium unraveled by localization microscopy

    NASA Astrophysics Data System (ADS)

    Renz, Marc; Rendler, Torsten; Börsch, Michael

    2012-03-01

    FoF1-ATP synthases in Escherichia coli (E. coli) bacteria are membrane-bound enzymes which use an internal protondriven rotary double motor to catalyze the synthesis of adenosine triphosphate (ATP). According to the 'chemiosmotic hypothesis', a series of proton pumps generate the necessary pH difference plus an electric potential across the bacterial plasma membrane. These proton pumps are redox-coupled membrane enzymes which are possibly organized in supercomplexes, as shown for the related enzymes in the mitochondrial inner membrane. We report diffusion measurements of single fluorescent FoF1-ATP synthases in living E. coli by localization microscopy and single enzyme tracking to distinguish a monomeric enzyme from a supercomplex-associated form in the bacterial membrane. For quantitative mean square displacement (MSD) analysis, the limited size of the observation area in the membrane with a significant membrane curvature had to be considered. The E. coli cells had a diameter of about 500 nm and a length of about 2 to 3 μm. Because the surface coordinate system yielded different localization precision, we applied a sliding observation window approach to obtain the diffusion coefficient D = 0.072 μm2/s of FoF1-ATP synthase in living E. coli cells.

  12. 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.…

  13. Transport proteins promoting Escherichia coli pathogenesis.

    PubMed

    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.

  14. Engineering Escherichia coli for methanol conversion.

    PubMed

    Müller, Jonas E N; Meyer, Fabian; Litsanov, Boris; Kiefer, Patrick; Potthoff, Eva; Heux, Stéphanie; Quax, Wim J; Wendisch, Volker F; Brautaset, Trygve; Portais, Jean-Charles; Vorholt, Julia A

    2015-03-01

    Methylotrophic bacteria utilize methanol and other reduced one-carbon compounds as their sole source of carbon and energy. For this purpose, these bacteria evolved a number of specialized enzymes and pathways. Here, we used a synthetic biology approach to select and introduce a set of "methylotrophy genes" into Escherichia coli based on in silico considerations and flux balance analysis to enable methanol dissimilation and assimilation. We determined that the most promising approach allowing the utilization of methanol was the implementation of NAD-dependent methanol dehydrogenase and the establishment of the ribulose monophosphate cycle by expressing the genes for hexulose-6-phosphate synthase (Hps) and 6-phospho-3-hexuloisomerase (Phi). To test for the best-performing enzymes in the heterologous host, a number of enzyme candidates from different donor organisms were selected and systematically analyzed for their in vitro and in vivo activities in E. coli. Among these, Mdh2, Hps and Phi originating from Bacillus methanolicus were found to be the most effective. Labeling experiments using (13)C methanol with E. coli producing these enzymes showed up to 40% incorporation of methanol into central metabolites. The presence of the endogenous glutathione-dependent formaldehyde oxidation pathway of E. coli did not adversely affect the methanol conversion rate. Taken together, the results of this study represent a major advancement towards establishing synthetic methylotrophs by gene transfer.

  15. 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

  16. Extracellular recombinant protein production from Escherichia coli.

    PubMed

    Ni, Ye; Chen, Rachel

    2009-11-01

    Escherichia coli is the most commonly used host for recombinant protein production and metabolic engineering. Extracellular production of enzymes and proteins is advantageous as it could greatly reduce the complexity of a bioprocess and improve product quality. Extracellular production of proteins is necessary for metabolic engineering applications in which substrates are polymers such as lignocelluloses or xenobiotics since adequate uptake of these substrates is often an issue. The dogma that E. coli secretes no protein has been challenged by the recognition of both its natural ability to secrete protein in common laboratory strains and increased ability to secrete proteins in engineered cells. The very existence of this review dedicated to extracellular production is a testimony for outstanding achievements made collectively by the community in this regard. Four strategies have emerged to engineer E. coli cells to secrete recombinant proteins. In some cases, impressive secretion levels, several grams per liter, were reached. This secretion level is on par with other eukaryotic expression systems. Amid the optimism, it is important to recognize that significant challenges remain, especially when considering the success cannot be predicted a priori and involves much trials and errors. This review provides an overview of recent developments in engineering E. coli for extracellular production of recombinant proteins and an analysis of pros and cons of each strategy.

  17. E. Coli: Preventing Outbreaks at Camp.

    ERIC Educational Resources Information Center

    McKinney, Mary D.

    1996-01-01

    One strain of E. coli is not usually found in foods, but has been related to consumption of undercooked ground beef. Symptoms are stomach cramps and diarrhea, and 2-7% of infections lead to hemolytic uremic syndrome, which is life threatening. Camps can prevent outbreaks by avoiding uncooked meat on overnight campouts and requiring appropriate…

  18. Travelers' diarrhea and toxigenic Escherichia coli.

    PubMed

    Gorbach, S L; Kean, B H; Evans, D G; Evans, D J; Bessudo, D

    1975-05-01

    In a group of 133 United States students studied for 18 days after arriving in Mexico, diarrhea developed in 38 (29 per cent). Diarrhea rarely began before the fourth day, and the mean onset was 13 days after arrival. Symptoms lasted an average of 3.4 days but persisted in 21 per cent of sick students. Heat-labile enterotoxin-producing Escheria coli was found in the stools of 72 per cent of sick and 15 per cent of healthy students. None had heat-labile Esch. coli when they entered Mexico. The incubation period was short, generally 24 to 48 hours, and the carrier state was five days or less in 82 per cent of students surveyed. Entamoeba histolytica was found in 6 per cent of cases of diarrhea, but not salmonella, shigella or penetrating Esch. coli. These studies suggest that approximately 70 per cent of travelers' diarrhea in Mexico is associated with heat-labile toxigenic strains of Esch. coli.

  19. Hybrid speciation in agricultural Campylobacter coli

    USDA-ARS?s Scientific Manuscript database

    Introduction Hybridization between distantly related organisms can facilitate rapid adaptation but is constrained by epistatic fitness interactions. The zoonotic pathogens Campylobacter coli and C. jejuni differ from each other at an average of nearly 40 amino acids per gene. Nevertheless, they have...

  20. Detection of O antigens in Escherichia coli

    USDA-ARS?s Scientific Manuscript database

    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. Gentamicin: effect on E. coli in space

    NASA Technical Reports Server (NTRS)

    Kacena, M. A.; Todd, P.

    1999-01-01

    Previous investigations have shown that liquid bacterial cultures grown in space flight were not killed as effectively by antibiotic treatments as were cultures grown on Earth. However, the cause for the decreased antibiotic effectiveness remains unknown. Possible explanations include modified cell proliferation and modified antibiotic transport in the culture medium. Escherichia coli cultures were grown in space flight (STS-69 and STS-73), with and without gentamicin, on a solid agar substrate thus eliminating fluid effects and reducing the unknowns associated with space-flight bacterial cultures in suspension. This research showed that E. coli cultures grown in flight on agar for 24 to 27 hours experienced a heightened growth compared to simultaneous controls. However, addition of gentamicin to the agar killed the bacteria such that both flight and ground control E. coli samples had similar final cell concentrations. Therefore, while the reported existence of a decrease in antibiotic effectiveness in liquid cultures remains unexplained, these data suggest that gentamicin in space flight was at least as effective as, if not more effective than, on Earth, when E. coli cells were grown on agar.

  2. Engineering Escherichia coli to bind to cyanobacteria.

    PubMed

    Zhang, Zijian; Meng, Liuyi; Ni, Congjian; Yao, Lanqiu; Zhang, Fengyu; Jin, Yuji; Mu, Xuelang; Zhu, Shiyu; Lu, Xiaoyu; Liu, Shiyu; Yu, Congyu; Wang, Chenggong; Zheng, Pu; Wu, Jie; Kang, Li; Zhang, Haoqian M; Ouyang, Qi

    2017-03-01

    We engineered Escherichia coli cells to bind to cyanobacteria by heterologously producing and displaying lectins of the target cyanobacteria on their surface. To prove the efficacy of our approach, we tested this design on Microcystis aeruginosa with microvirin (Mvn), the lectin endogenously produced by this cyanobacterium. The coding sequence of Mvn was C-terminally fused to the ice nucleation protein NC (INPNC) gene and expressed in E. coli. Results showed that E. coli cells expressing the INPNC::Mvn fusion protein were able to bind to M. aeruginosa and the average number of E. coli cells bound to each cyanobacterial cell was enhanced 8-fold. Finally, a computational model was developed to simulate the binding reaction and help reconstruct the binding parameters. To our best knowledge, this is the first report on the binding of two organisms in liquid culture mediated by the surface display of lectins and it may serve as a novel approach to mediate microbial adhesion.

  3. Widespread Antisense Transcription in Escherichia coli

    PubMed Central

    Dornenburg, James E.; DeVita, Anne M.; Palumbo, Michael J.; Wade, Joseph T.

    2010-01-01

    ABSTRACT The vast majority of annotated transcripts in bacteria are mRNAs. Here we identify ~1,000 antisense transcripts in the model bacterium Escherichia coli. We propose that these transcripts are generated by promiscuous transcription initiation within genes and that many of them regulate expression of the overlapping gene. PMID:20689751

  4. Ethanol production using engineered mutant E. coli

    DOEpatents

    Ingram, Lonnie O.; Clark, David P.

    1991-01-01

    The subject invention concerns novel means and materials for producing ethanol as a fermentation product. Mutant E. coli are transformed with a gene coding for pyruvate decarboxylase activity. The resulting system is capable of producing relatively large amounts of ethanol from a variety of biomass sources.

  5. E. Coli: Preventing Outbreaks at Camp.

    ERIC Educational Resources Information Center

    McKinney, Mary D.

    1996-01-01

    One strain of E. coli is not usually found in foods, but has been related to consumption of undercooked ground beef. Symptoms are stomach cramps and diarrhea, and 2-7% of infections lead to hemolytic uremic syndrome, which is life threatening. Camps can prevent outbreaks by avoiding uncooked meat on overnight campouts and requiring appropriate…

  6. Gentamicin: effect on E. coli in space

    NASA Technical Reports Server (NTRS)

    Kacena, M. A.; Todd, P.

    1999-01-01

    Previous investigations have shown that liquid bacterial cultures grown in space flight were not killed as effectively by antibiotic treatments as were cultures grown on Earth. However, the cause for the decreased antibiotic effectiveness remains unknown. Possible explanations include modified cell proliferation and modified antibiotic transport in the culture medium. Escherichia coli cultures were grown in space flight (STS-69 and STS-73), with and without gentamicin, on a solid agar substrate thus eliminating fluid effects and reducing the unknowns associated with space-flight bacterial cultures in suspension. This research showed that E. coli cultures grown in flight on agar for 24 to 27 hours experienced a heightened growth compared to simultaneous controls. However, addition of gentamicin to the agar killed the bacteria such that both flight and ground control E. coli samples had similar final cell concentrations. Therefore, while the reported existence of a decrease in antibiotic effectiveness in liquid cultures remains unexplained, these data suggest that gentamicin in space flight was at least as effective as, if not more effective than, on Earth, when E. coli cells were grown on agar.

  7. Inactivation of Escherichia coli by ultrasonic irradiation.

    PubMed

    Furuta, M; Yamaguchi, M; Tsukamoto, T; Yim, B; Stavarache, C E; Hasiba, K; Maeda, Y

    2004-04-01

    Ultrasonic inactivation of Escherichia coli XL1-Blue has been investigated by high-intensity ultrasonic waves from horn type sonicator (27.5 kHz) utilizing the "squeeze-film effect". The amplitude of the vibration face contacting the sample solution was used as an indication of the ultrasonic power intensity. The inactivation of the E. coli cells by ultrasonic irradiation shows pseudo first-order behavior. The inactivation rate constant gradually increased with increasing amplitude of the vibration face and showed rapid increase above 3 microm (p-p). In contrast, the H2O2 formation was not observed below 3 microm (p-p), indicating that the ultrasonic shock wave might be more important than indirect effect of OH radicals formed by ultrasonic cavitation in this system. The optimal thickness of the squeeze film was determined as 2 mm for the E. coli inactivation. More than 99% of E. coli cells was inactivated within 180-s sonication at the amplitude of 3 microm (p-p) and 2 mm of the thickness of the squeeze film.

  8. 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.…

  9. Phagocytic and chemiluminescent responses of mouse peritoneal macrophages to living and killed Salmonella typhimurium and other bacteria

    SciTech Connect

    Tomita, T.; Blumenstock, E.; Kanegasaki, S.

    1981-06-01

    In the presence of luminol, resident as well as thioglycolate-induced and immunized macrophages emitted chemiluminescence more efficiently when the cells were exposed to living Salmonella typhimurium than when they were exposed to the same bacterium killed by ultraviolet light or heat. This phenomenon was observed whether or not the bacterium was opsonized. The different response to living and killed bacteria was also found with Escherichia coli, Pseudomonas aeruginosa, Proteus morganii, and Enterobacter aerogenes, but not with Shigella sonnei, Klebsiella pneumoniae, and Propionibacterium acnes. The results suggest that macrophages respond better to living, motile bacteria than to nonmotile or killed bacteria. The experimental results obtained with motility mutants of S. typhimurium, E. coli, and P. aeruginosa confirm that macrophages exposed to the motile bacteria emit chemiluminescence more efficiently and ingest the motile bacteria at a much faster rate than the nonmotile bacteria.

  10. Probiotics: "living drugs".

    PubMed

    Elmer, G W

    2001-06-15

    The uses, mechanisms of action, and safety of probiotics are discussed. Probiotics are live microorganisms or microbial mixtures administered to improve the patient's microbial balance, particularly the environment of the gastrointestinal tract and the vagina. The yeast Saccharomyces boulardii and the bacterium Lactobacillus rhamnosus, strain GG, have shown efficacy in clinical trials for the prevention of antimicrobial-associated diarrhea. Other probiotics that have demonstrated at least some promise as prophylaxis for this type of diarrhea are Lactobacillus acidophilus, Bifidobacterium longum, and Enterococcus faecium. The use of S. boulardii as an adjunctive treatment to therapy with metronidazole or vancomycin has been found in controlled studies to decrease further recurrences of Clostridium difficile-associated disease. Other gastrointestinal disorders for which probiotics have been studied include traveler's diarrhea, acute infantile diarrhea, and acute diarrhea in adults. Several Lactobacillus species given in yogurt or in tablet or suppository form have shown clinical efficacy as a treatment for vaginal infections. Lactobacillus strains have also been examined as a treatment for urinary-tract infections. Putative mechanisms of action of probiotics include production of pathogen-inhibitory substances, inhibition of pathogen attachment, inhibition of the action of microbial toxins, stimulation of immunoglobulin A, and trophic effects on intestinal mucosa. The available probiotics are considered nonpathogenic, but even benign microorganisms can be infective when a patient is severely debilitated or immunosuppressed. Probiotics have demonstrated an ability to prevent and treat some infections. Effective use of probiotics could decrease patients' exposure to antimicrobials. Additional controlled studies are needed to clearly define the safety and efficacy of these agents.

  11. Viruses as living processes.

    PubMed

    Dupré, John; Guttinger, Stephan

    2016-10-01

    The view that life is composed of distinct entities with well-defined boundaries has been undermined in recent years by the realisation of the near omnipresence of symbiosis. What had seemed to be intrinsically stable entities have turned out to be systems stabilised only by the interactions between a complex set of underlying processes (Dupré, 2012). This has not only presented severe problems for our traditional understanding of biological individuality but has also led some to claim that we need to switch to a process ontology to be able adequately to understand biological systems. A large group of biological entities, however, has been excluded from these discussions, namely viruses. Viruses are usually portrayed as stable and distinct individuals that do not fit the more integrated and collaborative picture of nature implied by symbiosis. In this paper we will contest this view. We will first discuss recent findings in virology that show that viruses can be 'nice' and collaborate with their hosts, meaning that they form part of integrated biological systems and processes. We further offer various reasons why viruses should be seen as processes rather than things, or substances. Based on these two claims we will argue that, far from serving as a counterexample to it, viruses actually enable a deeper understanding of the fundamentally interconnected and collaborative nature of nature. We conclude with some reflections on the debate as to whether viruses should be seen as living, and argue that there are good reasons for an affirmative answer to this question. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. The living publication

    SciTech Connect

    Terwilliger, Thomas C.

    2012-06-04

    Within the ICSTI Insights Series we offer three articles on the 'living publication' that is already available to practitioners in the important field of crystal structure determination and analysis. While the specific examples are drawn from this particular field, we invite readers to draw parallels in their own fields of interest. The first article describes the present state of the crystallographic living publication, already recognized by an ALPSP (Association of Learned and Professional Society Publishers) Award for Publishing Innovation in 2006. The second article describes the potential impact on the record of science as greater post-publication analysis becomes more common within currently accepted data deposition practices, using processed diffraction data as the starting point. The third article outlines a vision for the further improvement of crystallographic structure reports within potentially achievable enhanced data deposition practices, based upon raw (unprocessed) diffraction data. The IUCr in its Commissions and Journals has for many years emphasized the importance of publications being accompanied by data and the interpretation of the data in terms of atomic models. This has been followed as policy by numerous other journals in the field and its cognate disciplines. This practice has been well served by databases and archiving institutions such as the Protein Data Bank (PDB), the Cambridge Crystallographic Data Centre (CCDC), and the Inorganic Crystal Structure Database (ICSD). Normally the models that are archived are interpretations of the data, consisting of atomic coordinates with their displacement parameters, along with processed diffraction data from X-ray, neutron or electron diffraction studies. In our current online age, a reader can not only consult the printed word, but can display and explore the results with molecular graphics software of exceptional quality. Furthermore, the routine availability of processed diffraction data allows

  13. Effect of cosmic-ray shielding on the ultraweak bioluminescence emitted by cultures of Escherichia coli

    SciTech Connect

    Tilbury, R.N.; Quickenden, T.I.

    1987-11-01

    Neither the growth of Escherichia coli nor its associated luminescence was significantly affected when cultures were shielded from the soft component of cosmic rays. The study included experiments in which the cultures were shielded intermittently during their two periods of luminescence emission and experiments in which the cultures were continuously shielded throughout their entire growth cycle. These results do not support previous suggestions that the ultraweak bioluminescences from living organisms might be cosmic-ray-excited fluorescences induced in certain biological molecules synthesized during the various stages of growth.

  14. Introduction of the Escherichia coli gdhA gene into Rhizobium phaseoli: effect on nitrogen fixation.

    PubMed Central

    Bravo, A; Becerril, B; Mora, J

    1988-01-01

    Rhizobium phaseoli lacks glutamate dehydrogenase (GDH) and assimilates ammonium by the glutamine synthetase-glutamate synthase pathway. A strain of R. phaseoli harboring the Escherichia coli GDH structural gene (gdhA) was constructed. GDH activity was expressed in R. phaseoli in the free-living state and in symbiosis. Nodules with bacteroids that expressed GDH activity had severe impairment of nitrogen fixation. Also, R. phaseoli cells that lost GDH activity and assimilated ammonium by the glutamine synthetase-glutamate synthase pathway preferentially nodulated Phaseolus vulgaris. PMID:2892830

  15. Diarrhea, bacteremia and multiorgan dysfunction due to an extraintestinal pathogenic Escherichia coli strain with enteropathogenic E. coli genes.

    PubMed

    Kessler, Robert; Nisa, Shahista; Hazen, Tracy H; Horneman, Amy; Amoroso, Anthony; Rasko, David A; Donnenberg, Michael S

    2015-11-01

    A 55-year-old man with well-controlled HIV had severe diarrhea for 3 weeks and developed multiorgan dysfunction and bacteremia due to Escherichia coli. The genome of the patient's isolate had features characteristic of extraintestinal pathogenic E. coli and genes distantly related to those defining enteropathogenic E. coli.

  16. CRISPRi engineering E. coli for morphology diversification.

    PubMed

    Elhadi, Dina; Lv, Li; Jiang, Xiao-Ran; Wu, Hong; Chen, Guo-Qiang

    2016-11-01

    Microbial morphology engineering has recently become interesting for biotechnology. Genes ftsZ and mreB encoding proteins of bacterial fission ring and skeletons, respectively, are essential for cell growth, they both are the most important genes keeping the bacterial shapes including the cell length and width, respectively. Clustered regularly interspaced short palindromic repeats interference, abbreviated as CRISPRi, was for the first time used in this study to regulate expression intensities of ftsZ or/and mreB in E. coli. Five sgRNAs associated with CRISPRi were designed and synthesized, respectively, to target five various locations on genes ftsZ or mreB encoded in the E. coli chromosome, resulting in various reduced expression levels of ftsZ or/and mreB, respectively, forming elongated or/and fatter cells. Repressions on gene expressions of ftsZ or/and mreB could be further intensified by combining various sgRNAs together. It was found that the stronger the repression on genes ftsZ or/and mreB, the longer the E. coli fibers, and the larger the E. coli cells. Combined repressions on expressions of ftsZ and mreB generated long and larger E. coli with diverse morphologies including various sizes of gourds, bars, coccus, spindles, multi-angles and ellipsoids. In all cases, accumulations of intracellular biopolyester polyhydroxybutyrate (PHB) were in direct proportional to the intracellular volumes, ranging from 40% to 80% PHB in bacterial cell dry weights, depending on the cell volumes increases by the above CRISPRi applications.

  17. Community Living Skills: Nutrition I.

    ERIC Educational Resources Information Center

    Kreps, Alice Roelofs; Dreith, Rita Vallero

    One of twenty course guides in the Community Living Skills Guide for the College for Living series, this document provides guidelines and workbook activities for the course, Nutrition I. The series of courses for developmentally disabled adults is intended to supplement residential programs and to aid in orienting institutionalized persons to…

  18. Framework for Healthful Living Education.

    ERIC Educational Resources Information Center

    North Carolina State Dept. of Public Instruction, Raleigh.

    The Healthful Living Education program promotes behaviors that contribute to a healthful lifestyle and improved quality of life for all students. The Framework for Healthy Living Education supports and reinforces the goals and objectives of its three major components: health education, physical education, and alcohol and other drugs. When the…

  19. Connecting with assisted living consumers.

    PubMed

    Cameron, Kathleen A; Pinkowitz, Jackie

    2009-01-01

    Connecting with residents and their family members should be considered an integral part of medication therapy management services that pharmacists provide to assisted living communities. This article provides suggestions on how pharmacists can better connect and communicate with current and future assisted-living consumers and staff to optimize medication use, maintain resident function, and help residents age in place.

  20. SOLO: Self Organizing Live Objects

    DTIC Science & Technology

    2008-12-01

    mance needs can vary in use-dependent ways. For example in a content sharing system, the lag-tolerance for a live - streaming use may depend on the kind...USA, Octo- ber 2005. [15] Qi Huang, Hai Jin, and Xiaofei Liao, “P2P Live Streaming with Tree-Mesh based Hybrid Overlay”, In Pro- ceedings of ICPP

  1. Community Living Skills: Nutrition I.

    ERIC Educational Resources Information Center

    Kreps, Alice Roelofs; Dreith, Rita Vallero

    One of twenty course guides in the Community Living Skills Guide for the College for Living series, this document provides guidelines and workbook activities for the course, Nutrition I. The series of courses for developmentally disabled adults is intended to supplement residential programs and to aid in orienting institutionalized persons to…

  2. Community Living Skills Guide: Sexuality.

    ERIC Educational Resources Information Center

    Breen, Kathy

    One of twenty course guides in the Community Living Skills Guide for the College for Living series, this document provides guidelines and workbook activities for the course, Sexuality. The series of courses for developmentally disabled adults is intended to supplement residential programs and to aid in orienting institutionalized persons to…

  3. Provider lived experience and stigma.

    PubMed

    Harris, J Irene; Leskela, Jennie; Hoffman-Konn, Lisa

    2016-01-01

    Despite professional values about advocacy for people managing mental health challenges, research on mental health providers indicates that this group expresses as much or more stigma than laypeople. This article reports on a continuing education needs assessment of 101 mental health providers, including evaluation of (a) knowledge about recovery-oriented care, (b) work engagement, (c) provider lived experience with mental health challenges, and (d) stigma, measured as disidentification. In this group of providers, recovery knowledge, lived experience, and work engagement were associated with less stigma toward clients. Recovery knowledge and work engagement were associated with less stigma toward other providers with lived experience, but having lived experience was not associated with stigma toward other providers with lived experience. Findings suggest that the professional culture of nondisclosure may be a factor that increases provider stigma and should be a topic for further research. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  4. Where Plumes Live

    NASA Astrophysics Data System (ADS)

    King, S. D.

    2004-12-01

    From the perspective of fluid dynamics, `Plumes or not?' might be the wrong question. Let me begin by defining a few terms. Plume with a `P' is the well-known thermal structure with thin (order 100 km) tail and large, bulbous head that originates at the core-mantle boundary. The thin tail/large, bulbous-head morphology has been generated in a number of laboratory and numerical experiments. It can be seen, for example, on the cover of the famous fluid dynamics text by Batchelor. There is a clearly-defined range of parameters for which this structure is the preferred solution for instabilities arising from a bottom boundary layer in a convecting fluid. For example, a strong temperature-dependent rheology is needed. By contrast, plume with a `p' is any cylindrical or quasi-cylindrical instability originating from a thermal (or thermo-chemical) boundary layer. In fluid dynamics plume is sometimes used interchangeable with jet. Unless there is a very small temperature drop across the core-mantle boundary or a rather remarkable balance between temperature and composition at the base of the mantle, there are almost certainly plumes. (Note the little p.) Are these plumes the thermal structures with thin (order 100 km) tails and large bulbous heads or could they be broad, hot regions such as the degree 2 pattern seen in global seismic tomography images of the lower mantle, or the disconnected droplets seen in chaotic convection? To study this question, I will present a sequence of numerical `experiments' that illustrate the morphology of instabilities from a basal thermal boundary layer, i.e., plumes. Some of the aspects I will present include: spherical geometry, temperature-and pressure-dependence of rheology, internal heating, pressure-dependent coefficient of thermal expansion, variable coefficient of thermal diffusivity, phase transformations, and compositional layering at the base of the mantle. The goal is to map out the parameters and conditions where Plumes live

  5. Mass and density measurements of live and dead Gram-negative and Gram-positive bacterial populations.

    PubMed

    Lewis, Christina L; Craig, Caelli C; Senecal, Andre G

    2014-06-01

    Monitoring cell growth and measuring physical features of food-borne pathogenic bacteria are important for better understanding the conditions under which these organisms survive and proliferate. To address this challenge, buoyant masses of live and dead Escherichia coli O157:H7 and Listeria innocua were measured using Archimedes, a commercially available suspended microchannel resonator (SMR). Cell growth was monitored with Archimedes by observing increased cell concentration and buoyant mass values of live growing bacteria. These growth data were compared to optical density measurements obtained with a Bioscreen system. We observed buoyant mass measurements with Archimedes at cell concentrations between 10(5) and 10(8) cells/ml, while growth was not observed with optical density measurements until the concentration was 10(7) cells/ml. Buoyant mass measurements of live and dead cells with and without exposure to hydrogen peroxide stress were also compared; live cells generally had a larger buoyant mass than dead cells. Additionally, buoyant mass measurements were used to determine cell density and total mass for both live and dead cells. Dead E. coli cells were found to have a larger density and smaller total mass than live E. coli cells. In contrast, density was the same for both live and dead L. innocua cells, while the total mass was greater for live than for dead cells. These results contribute to the ongoing challenge to further develop existing technologies used to observe cell populations at low concentrations and to measure unique physical features of cells that may be useful for developing future diagnostics.

  6. Mass and Density Measurements of Live and Dead Gram-Negative and Gram-Positive Bacterial Populations

    PubMed Central

    Craig, Caelli C.; Senecal, Andre G.

    2014-01-01

    Monitoring cell growth and measuring physical features of food-borne pathogenic bacteria are important for better understanding the conditions under which these organisms survive and proliferate. To address this challenge, buoyant masses of live and dead Escherichia coli O157:H7 and Listeria innocua were measured using Archimedes, a commercially available suspended microchannel resonator (SMR). Cell growth was monitored with Archimedes by observing increased cell concentration and buoyant mass values of live growing bacteria. These growth data were compared to optical density measurements obtained with a Bioscreen system. We observed buoyant mass measurements with Archimedes at cell concentrations between 105 and 108 cells/ml, while growth was not observed with optical density measurements until the concentration was 107 cells/ml. Buoyant mass measurements of live and dead cells with and without exposure to hydrogen peroxide stress were also compared; live cells generally had a larger buoyant mass than dead cells. Additionally, buoyant mass measurements were used to determine cell density and total mass for both live and dead cells. Dead E. coli cells were found to have a larger density and smaller total mass than live E. coli cells. In contrast, density was the same for both live and dead L. innocua cells, while the total mass was greater for live than for dead cells. These results contribute to the ongoing challenge to further develop existing technologies used to observe cell populations at low concentrations and to measure unique physical features of cells that may be useful for developing future diagnostics. PMID:24705320

  7. Nonperturbative imaging of nucleoid morphology in live bacterial cells during an antimicrobial peptide attack.

    PubMed

    Bakshi, Somenath; Choi, Heejun; Rangarajan, Nambirajan; Barns, Kenneth J; Bratton, Benjamin P; Weisshaar, James C

    2014-08-01

    Studies of time-dependent drug and environmental effects on single, live bacterial cells would benefit significantly from a permeable, nonperturbative, long-lived fluorescent stain specific to the nucleoids (chromosomal DNA). The ideal stain would not affect cell growth rate or nucleoid morphology and dynamics, even during laser illumination for hundreds of camera frames. In this study, time-dependent, single-cell fluorescence imaging with laser excitation and a sensitive electron-multiplying charge-coupled-device (EMCCD) camera critically tested the utility of "dead-cell stains" (SYTOX orange and SYTOX green) and "live-cell stains" (DRAQ5 and SYTO 61) and also 4',6-diamidino-2-phenylindole (DAPI). Surprisingly, the dead-cell stains were nearly ideal for imaging live Escherichia coli, while the live-cell stains and DAPI caused nucleoid expansion and, in some cases, cell permeabilization and the halting of growth. SYTOX orange performed well for both the Gram-negative E. coli and the Gram-positive Bacillus subtilis. In an initial application, we used two-color fluorescence imaging to show that the antimicrobial peptide cecropin A destroyed nucleoid-ribosome segregation over 20 min after permeabilization of the E. coli cytoplasmic membrane, reminiscent of the long-term effects of the drug rifampin. In contrast, the human cathelicidin LL-37, while similar to cecropin A in structure, length, charge, and the ability to permeabilize bacterial membranes, had no observable effect on nucleoid-ribosome segregation. Possible underlying causes are suggested. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  8. D-Alanine-Controlled Transient Intestinal Mono-Colonization with Non-Laboratory-Adapted Commensal E. coli Strain HS.

    PubMed

    Cuenca, Miguelangel; Pfister, Simona P; Buschor, Stefanie; Bayramova, Firuza; Hernandez, Sara B; Cava, Felipe; Kuru, Erkin; Van Nieuwenhze, Michael S; Brun, Yves V; Coelho, Fernanda M; Hapfelmeier, Siegfried

    2016-01-01

    Soon after birth the mammalian gut microbiota forms a permanent and collectively highly resilient consortium. There is currently no robust method for re-deriving an already microbially colonized individual again-germ-free. We previously developed the in vivo growth-incompetent E. coli K-12 strain HA107 that is auxotrophic for the peptidoglycan components D-alanine (D-Ala) and meso-diaminopimelic acid (Dap) and can be used to transiently associate germ-free animals with live bacteria, without permanent loss of germ-free status. Here we describe the translation of this experimental model from the laboratory-adapted E. coli K-12 prototype to the better gut-adapted commensal strain E. coli HS. In this genetic background it was necessary to complete the D-Ala auxotrophy phenotype by additional knockout of the hypothetical third alanine racemase metC. Cells of the resulting fully auxotrophic strain assembled a peptidoglycan cell wall of normal composition, as long as provided with D-Ala and Dap in the medium, but could not proliferate a single time after D-Ala/Dap removal. Yet, unsupplemented bacteria remained active and were able to complete their cell cycle with fully sustained motility until immediately before autolytic death. Also in vivo, the transiently colonizing bacteria retained their ability to stimulate a live-bacteria-specific intestinal Immunoglobulin (Ig)A response. Full D-Ala auxotrophy enabled rapid recovery to again-germ-free status. E. coli HS has emerged from human studies and genomic analyses as a paradigm of benign intestinal commensal E. coli strains. Its reversibly colonizing derivative may provide a versatile research tool for mucosal bacterial conditioning or compound delivery without permanent colonization.

  9. D-Alanine-Controlled Transient Intestinal Mono-Colonization with Non-Laboratory-Adapted Commensal E. coli Strain HS

    PubMed Central

    Buschor, Stefanie; Bayramova, Firuza; Hernandez, Sara B.; Cava, Felipe; Kuru, Erkin; Van Nieuwenhze, Michael S.; Brun, Yves V.; Coelho, Fernanda M.; Hapfelmeier, Siegfried

    2016-01-01

    Soon after birth the mammalian gut microbiota forms a permanent and collectively highly resilient consortium. There is currently no robust method for re-deriving an already microbially colonized individual again-germ-free. We previously developed the in vivo growth-incompetent E. coli K-12 strain HA107 that is auxotrophic for the peptidoglycan components D-alanine (D-Ala) and meso-diaminopimelic acid (Dap) and can be used to transiently associate germ-free animals with live bacteria, without permanent loss of germ-free status. Here we describe the translation of this experimental model from the laboratory-adapted E. coli K-12 prototype to the better gut-adapted commensal strain E. coli HS. In this genetic background it was necessary to complete the D-Ala auxotrophy phenotype by additional knockout of the hypothetical third alanine racemase metC. Cells of the resulting fully auxotrophic strain assembled a peptidoglycan cell wall of normal composition, as long as provided with D-Ala and Dap in the medium, but could not proliferate a single time after D-Ala/Dap removal. Yet, unsupplemented bacteria remained active and were able to complete their cell cycle with fully sustained motility until immediately before autolytic death. Also in vivo, the transiently colonizing bacteria retained their ability to stimulate a live-bacteria-specific intestinal Immunoglobulin (Ig)A response. Full D-Ala auxotrophy enabled rapid recovery to again-germ-free status. E. coli HS has emerged from human studies and genomic analyses as a paradigm of benign intestinal commensal E. coli strains. Its reversibly colonizing derivative may provide a versatile research tool for mucosal bacterial conditioning or compound delivery without permanent colonization. PMID:27002976

  10. Sources of Escherichia coli in a Coastal Subtropical Environment

    PubMed Central

    Solo-Gabriele, Helena M.; Wolfert, Melinda A.; Desmarais, Timothy R.; Palmer, Carol J.

    2000-01-01

    Sources of Escherichia coli in a coastal waterway located in Ft. Lauderdale, Fla., were evaluated. The study consisted of an extensive program of field measurements designed to capture spatial and temporal variations in E. coli concentrations as well as experiments conducted under laboratory-controlled conditions. E. coli from environmental samples was enumerated by using a defined substrate technology (Colilert-18). Field sampling tasks included sampling the length of the North Fork to identify the river reach contributing high E. coli levels, autosampler experiments at two locations, and spatially intense sampling efforts at hot spots. Laboratory experiments were designed to simulate tidal conditions within the riverbank soils. The results showed that E. coli entered the river in a large pulse during storm conditions. After the storm, E. coli levels returned to baseline levels and varied in a cyclical pattern which correlated with tidal cycles. The highest concentrations were observed during high tide, whereas the lowest were observed at low tide. This peculiar pattern of E. coli concentrations between storm events was caused by the growth of E. coli within riverbank soils which were subsequently washed in during high tide. Laboratory analysis of soil collected from the riverbanks showed increases of several orders of magnitude in soil E. coli concentrations. The ability of E. coli to multiply in the soil was found to be a function of soil moisture content, presumably due to the ability of E. coli to outcompete predators in relatively dry soil. The importance of soil moisture in regulating the multiplication of E. coli was found to be critical in tidally influenced areas due to periodic wetting and drying of soils in contact with water bodies. Given the potential for growth in such systems, E. coli concentrations can be artificially elevated above that expected from fecal impacts alone. Such results challenge the use of E. coli as a suitable indicator of water

  11. [Elimination of multidrug resistance in E. coli in calves in vivo with rimactan].

    PubMed

    Karaivanov, L; Koleva, P; Bonovska, M; Mateev, M; Kozarev, A

    1980-01-01

    An experiment was carried out for eliminating the multimedicinal resistance markers of E. coli, populating the intestinal tract of calves, in vivo with rimactan introduced per os, and rationed 10 mg/kg of live weight, once during a period of 8 days. The highest percentage and the longest elimination were observed for the neomycin, the novobiocin and the chlornitromycin resistance markers. The elimination was weaker for the erythromycin, the streptomycin and the kanamycin markers and the weakest was for the penicillin and tetracycline markers. There appeared a difference in the elimination of the resistance markers with the different calves, especially for the markers with a low degree of elimination, depending on the individual peculiarities of the calves. Riphamycin proved to be an eliminating means for the resistance markers of E coli in vivo of calves suffering from enteritis. Alongside with the elimination of the resistance markers, due to the treatment of calves with rimactan, an almost complete recovery was achieved. Rimactan is a reliable means for fighting enteric illnesses with calves, caused by enteropathogenic E. coli.

  12. Escherichia coli Producing Colibactin Triggers Premature and Transmissible Senescence in Mammalian Cells

    PubMed Central

    Secher, Thomas; Samba-Louaka, Ascel; Oswald, Eric; Nougayrède, Jean-Philippe

    2013-01-01

    Cellular senescence is an irreversible state of proliferation arrest evoked by a myriad of stresses including oncogene activation, telomere shortening/dysfunction and genotoxic insults. It has been associated with tumor activation, immune suppression and aging, owing to the secretion of proinflammatory mediators. The bacterial genotoxin colibactin, encoded by the pks genomic island is frequently harboured by Escherichia coli strains of the B2 phylogenetic group. Mammalian cells exposed to live pks+ bacteria exhibit DNA-double strand breaks (DSB) and undergo cell-cycle arrest and death. Here we show that cells that survive the acute bacterial infection with pks+ E. coli display hallmarks of cellular senescence: chronic DSB, prolonged cell-cycle arrest, enhanced senescence-associated β-galactosidase (SA-β-Gal) activity, expansion of promyelocytic leukemia nuclear foci and senescence-associated heterochromatin foci. This was accompanied by reactive oxygen species production and pro-inflammatory cytokines, chemokines and proteases secretion. These mediators were able to trigger DSB and enhanced SA-β-Gal activity in bystander recipient cells treated with conditioned medium from senescent cells. Furthermore, these senescent cells promoted the growth of human tumor cells. In conclusion, the present data demonstrated that the E. coli genotoxin colibactin induces cellular senescence and subsequently propel bystander genotoxic and oncogenic effects. PMID:24116215

  13. NanoSIMS50 analyses of Ar/18O2 plasma-treated Escherichia coli bacteria

    NASA Astrophysics Data System (ADS)

    Clément, F.; Lecoq, E.; Duday, D.; Belmonte, T.; Audinot, J.-N.; Lentzen, E.; Penny, C.; Cauchie, H.-M.; Choquet, P.

    2011-11-01

    Reactive oxygen species (ROS) can be produced by electrical discharges and can be transported in uncharged regions by gas flows, in the so-called afterglows. These species are well known to have bactericidal effects but interaction mechanisms that occur with living micro-organisms remain misunderstood. In order to better understand these interactions, new analysis approaches are necessary. High-lateral-resolution secondary ion mass spectrometry (NanoSIMS) is one of the most promising ways of retrieving additional information on bacteria plasma inactivation mechanisms by combining isotopic imaging of plasma-treated bacteria and the use of 18O2 as process gas. Indeed, this technology combines a lateral resolution of a few tens of nanometres that is sufficient to image the interior of bacteria, and a high mass resolution allowing detection of isotopes present in low quantities (a few ppm or lower) within the bacteria. The present paper deals with Ar-18O2 (2%) plasma treatment, through low-pressure microwave late afterglows, of Escherichia coli bacteria and their elemental and isotopic imaging by NanoSIMS. E. coli bacteria have been exposed to this reactive medium for varying treatment duration while keeping all other parameters unchanged. Our main goal is to determine whether the quantity of 18O fixed in treated bacteria and the NanoSIMS50 lateral resolution are sufficient to give additional information on E. coli bacteria-plasma interaction.

  14. Tracking pathogen transmission at the human-wildlife interface: banded mongoose and Escherichia coli.

    PubMed

    Pesapane, R; Ponder, M; Alexander, K A

    2013-06-01

    A primary challenge to managing emerging infectious disease is identifying pathways that allow pathogen transmission at the human-wildlife interface. Using Escherichia coli as a model organism, we evaluated fecal bacterial transmission between banded mongoose (Mungos mungo) and humans in northern Botswana. Fecal samples were collected from banded mongoose living in protected areas (n = 87, 3 troops) and surrounding villages (n = 92, 3 troops). Human fecal waste was collected from the same environment (n = 46). Isolates were evaluated for susceptibility to 10 antibiotics. Resistant E. coli isolates from mongoose were compared to human isolates using rep-PCR fingerprinting and MLST-PCR. Antimicrobial resistant isolates were identified in 57 % of the mongoose fecal samples tested (range 31-78% among troops). At least one individual mongoose fecal sample demonstrated resistance to each tested antibiotic, and multidrug resistance was highest in the protected areas (40.9%). E. coli isolated from mongoose and human sources in this study demonstrated an extremely high degree of genetic similarity on rep-PCR (AMOVA, F ST = 0.0027, p = 0.18) with a similar pattern identified on MLST-PCR. Human waste may be an important source of microbial exposure to wildlife. Evidence of high levels of antimicrobial resistance even within protected areas identifies an emerging health threat and highlights the need for improved waste management in these systems.

  15. Escherichia coli Braun Lipoprotein (BLP) exhibits endotoxemia – like pathology in Swiss albino mice

    PubMed Central

    Lakshmikanth, Chikkamenahalli Lakshminarayana; Jacob, Shancy Petsel; Kudva, Avinash Kundadka; Latchoumycandane, Calivarathan; Yashaswini, Puttaraju Srikanta Murthy; Sumanth, Mosale Seetharam; Goncalves-de-Albuquerque, Cassiano F.; Silva, Adriana R.; Singh, Sridevi Annapurna; Castro-Faria-Neto, Hugo C.; Prabhu, Sandeep Kumble; McIntyre, Thomas M.; Marathe, Gopal Kedihithlu

    2016-01-01

    The endotoxin lipopolysaccharide (LPS) promotes sepsis, but bacterial peptides also promote inflammation leading to sepsis. We found, intraperitoneal administration of live or heat inactivated E. coli JE5505 lacking the abundant outer membrane protein, Braun lipoprotein (BLP), was less toxic than E. coli DH5α possessing BLP in Swiss albino mice. Injection of BLP free of LPS purified from E. coli DH5α induced massive infiltration of leukocytes in lungs and liver. BLP activated human polymorphonuclear cells (PMNs) ex vivo to adhere to denatured collagen in serum and polymyxin B independent fashion, a property distinct from LPS. Both LPS and BLP stimulated the synthesis of platelet activating factor (PAF), a potent lipid mediator, in human PMNs. In mouse macrophage cell line, RAW264.7, while both BLP and LPS similarly upregulated TNF-α and IL-1β mRNA; BLP was more potent in inducing cyclooxygenase-2 (COX-2) mRNA and protein expression. Peritoneal macrophages from TLR2−/− mice significantly reduced the production of TNF-α in response to BLP in contrast to macrophages from wild type mice. We conclude, BLP acting through TLR2, is a potent inducer of inflammation with a response profile both common and distinct from LPS. Hence, BLP mediated pathway may also be considered as an effective target against sepsis. PMID:27698491

  16. Bioconversion of Pinoresinol into Matairesinol by Use of Recombinant Escherichia coli

    PubMed Central

    Kuo, Han-Jung; Wei, Zhi-Yu; Lu, Pei-Chun; Huang, Pung-Ling

    2014-01-01

    Lignans, a class of dimeric phenylpropanoid derivative found in plants, such as whole grains and sesame and flax seeds, have anticancer activity and can act as phytoestrogens. The lignans secoisolariciresinol and matairesinol can be converted in the mammalian proximal colon into enterolactone and enterodiol, respectively, which reduce the risk of breast and colon cancer. To establish an efficient bioconversion system to generate matairesinol from pinoresinol, the genes encoding pinoresinol-lariciresinol reductase (PLR) and secoisolariciresinol dehydrogenase (SDH) were cloned from Podophyllum pleianthum Hance, an endangered herb in Taiwan, and the recombinant proteins, rPLR and rSDH, were expressed in Escherichia coli and purified. The two genes, termed plr-PpH and sdh-PpH, were also linked to form two bifunctional fusion genes, plr-sdh and sdh-plr, which were also expressed in E. coli and purified. Bioconversion in vitro at 22°C for 60 min showed that the conversion efficiency of fusion protein PLR-SDH was higher than that of the mixture of rPLR and rSDH. The percent conversion of (+)-pinoresinol to matairesinol was 49.8% using PLR-SDH and only 17.7% using a mixture of rPLR and rSDH. However, conversion of (+)-pinoresinol by fusion protein SDH-PLR stopped at the intermediate product, secoisolariciresinol. In vivo, (+)-pinoresinol was completely converted to matairesinol by living recombinant E. coli expressing PLR-SDH without addition of cofactors. PMID:24561584

  17. Bioconversion of pinoresinol into matairesinol by use of recombinant Escherichia coli.

    PubMed

    Kuo, Han-Jung; Wei, Zhi-Yu; Lu, Pei-Chun; Huang, Pung-Ling; Lee, Kung-Ta

    2014-05-01

    Lignans, a class of dimeric phenylpropanoid derivative found in plants, such as whole grains and sesame and flax seeds, have anticancer activity and can act as phytoestrogens. The lignans secoisolariciresinol and matairesinol can be converted in the mammalian proximal colon into enterolactone and enterodiol, respectively, which reduce the risk of breast and colon cancer. To establish an efficient bioconversion system to generate matairesinol from pinoresinol, the genes encoding pinoresinol-lariciresinol reductase (PLR) and secoisolariciresinol dehydrogenase (SDH) were cloned from Podophyllum pleianthum Hance, an endangered herb in Taiwan, and the recombinant proteins, rPLR and rSDH, were expressed in Escherichia coli and purified. The two genes, termed plr-PpH and sdh-PpH, were also linked to form two bifunctional fusion genes, plr-sdh and sdh-plr, which were also expressed in E. coli and purified. Bioconversion in vitro at 22°C for 60 min showed that the conversion efficiency of fusion protein PLR-SDH was higher than that of the mixture of rPLR and rSDH. The percent conversion of (+)-pinoresinol to matairesinol was 49.8% using PLR-SDH and only 17.7% using a mixture of rPLR and rSDH. However, conversion of (+)-pinoresinol by fusion protein SDH-PLR stopped at the intermediate product, secoisolariciresinol. In vivo, (+)-pinoresinol was completely converted to matairesinol by living recombinant E. coli expressing PLR-SDH without addition of cofactors.

  18. The Use of a Novel NanoLuc -Based Reporter Phage for the Detection of Escherichia coli O157:H7

    PubMed Central

    Zhang, Dandan; Coronel-Aguilera, Claudia P.; Romero, Patricia L.; Perry, Lynda; Minocha, Udit; Rosenfield, Carla; Gehring, Andrew G.; Paoli, George C.; Bhunia, Arun K.; Applegate, Bruce

    2016-01-01

    Rapid detection of the foodborne pathogen Escherichia coli O157:H7 is of vital importance for public health worldwide. Among detection methods, reporter phages represent unique and sensitive tools for the detection of E. coli O157:H7 from food as they are host-specific and able to differentiate live cells from dead ones. Upon infection, target bacteria become identifiable since reporter genes are expressed from the engineered phage genome. The E. coli O157:H7 bacteriophage ΦV10 was modified to express NanoLuc luciferase (Nluc) derived from the deep-sea shrimp Oplophorus gracilirostris. Once infected by the ΦV10 reporter phage, E. coli O157:H7 produces a strong bioluminescent signal upon addition of commercial luciferin (Nano-Glo®). Enrichment assays using E. coli O157:H7 grown in LB broth with a reporter phage concentration of 1.76 × 102 pfu ml−1 are capable of detecting approximately 5 CFU in 7 hours. Comparable detection was achieved within 9 hours using 9.23 × 103 pfu ml−1 of phage in selective culture enrichments of ground beef as a representative food matrix. Therefore we conclude that this NanoLuc reporter phage assay shows promise for detection of E. coli O157:H7 from food in a simple, fast and sensitive manner. PMID:27624517

  19. High-level synthesis of endochitinase ChiA74 in Escherichia coli K12 and its promising potential for use in biotechnology.

    PubMed

    Castañeda-Ramírez, J Cristóbal; de la Fuente-Salcido, Norma M; Salcedo-Hernández, Rubén; León-Galván, Fabiola; Bideshi, Dennis K; Barboza-Corona, J Eleazar

    2013-11-01

    In the present study, we expressed the chiA74 gene of Bacillus thuringiensis in Escherichia coli K12 and demonstrated that the active ChiA74 enzyme was produced at a high level in this strain. The ChiA74 enzymatic activity (in units per milliliter) was approximately 500 % greater in E. coli K12 when compared to that produced in E. coli DH5α. Moreover, we showed that, when using our protocol, ChiA74 preparations obtained from recombinant E. coli K12 did not contain live bacteria, although transformable DNA (erm, bla genes) was detected. Nucleic acids were subsequently easily eliminated when samples were treated with magnesium. Importantly, ChiA74 was secreted by E. coli K12 and the active enzyme was shown to generate chitin-derived oligosaccharides (C-OGS) with degrees of polymerization of 2, 3, 4, 5, and 6. From an applied perspective, the C-OGS showed activity against various pathogenic bacteria. In addition, we demonstrated that ChiA74 was not toxic to Hek 293 and 3T3 L1 cells, i.e., the enzyme did not induce apoptosis or affect normal cellular cycle and also did not produce abnormal changes in cell morphology. The potential biotechnological use of producing endochitinase of B. thuringiensis in a microorganism recognized as safe (i.e., E. coli K12) is discussed.

  20. Leukemia and risk of recurrent Escherichia coli bacteremia: genotyping implicates E. coli translocation from the colon to the bloodstream.

    PubMed

    Samet, A; Sledzińska, A; Krawczyk, B; Hellmann, A; Nowicki, S; Kur, J; Nowicki, B

    2013-11-01

    In patients with leukemia, the portal(s) and reasons for the persistence of an Escherichia coli recurrent bacteremia remain unclear. Adult Hematology Clinic (AHC) databases at the State Clinical Hospital in Gdańsk were reviewed to evaluate the frequency of E. coli bacteremia between 2002 and 2005. Blood and bowel E. coli strains were obtained and the genetic relatedness of the strains was analyzed. The rate of E. coli bacteremia per 1,000 admissions at the AHC was higher (85.0) than in the other clinics of the hospital (2.9), p < 0.001. A higher mortality was observed in patients with a history of E. coli versus non-E. coli bacteremia [30/95 (31 %) vs. 53/430 (12 %), p < 0.001]; 72.8 % of patients with leukemia had an unknown source of bacteremia. In 2005, 6 out of 25 (24 %) patients with leukemia had ≥2 episodes of E. coli-positive blood cultures. These gastrointestinal E. coli isolates were replaced within 3-8 weeks with a new E. coli H genotype. A recurrent episode of bacteremia was usually caused by an infection with a transient E. coli H genotype identical to that found in the subject's bowel. Consistent with the definition of bowel/blood translocation, the bowel appeared to be a portal for E. coli in these subjects and, hence, a clear source for their recurring bacteremia.

  1. The Living Expert System (LEXSYS)

    DTIC Science & Technology

    1988-05-12

    LEXSYS Living ~ ARMY SENIORSy tn LEADER DECISION MAKING TOOL FOR U.S. ARMY WAR COLLEGE CARLISLE BARRACKS, PA 17013-5050 VOL. I DISTRIUIn= STATDIIII...for open publication until It has been cleared by the appropriate mUlitav service or government agency. THE LIVING EXPERT SYSTEM A GROUP STUDY PROJECT...LTC, AR R. A. Pomager, Jr., LTC, MP E. R. Ruff, LTC, EN J. D. Tolleson, LTC, QM TITLE: The Living Expert System FORMAT: Group Study DATE: 1 May 1988

  2. Evidence for a human-specific Escherichia coli clone.

    PubMed

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

    2008-04-01

    Escherichia coli is a widespread commensal of the vertebrate intestinal tract. Until recently, no strong association between a particular clone and a given host species has been found. However, members of the B2 subgroup VIII clone with an O81 serotype appear to be human host specific. To determine the degree of host specificity exhibited by this clone, a PCR-based assay was used to screen 723 faecal and clinical isolates from humans, and 904 faecal isolates from animals. This clone was not detected among the animal isolates, but was discovered in people living in Africa, Europe and South America. The clone is rarely isolated from people suffering from intestinal or extraintestinal disease and is avirulent in a mouse model of extraintestinal infection. Fine-scale epidemiological analysis suggests that this clone is competitively dominant relative to other members of the B2 phylogenetic group and that it has increased in frequency over the past 20 years. This clone appears to be a good candidate for use as a probiotic, and may be suitable as an indicator of human faecal contamination in microbial source tracking studies.

  3. Shiga toxins decrease enterohaemorrhagic Escherichia coli survival within Acanthamoeba castellanii.

    PubMed

    Chekabab, Samuel M; Daigle, France; Charette, Steve J; Dozois, Charles M; Harel, Josée

    2013-07-01

    Enterohaemorrhagic Escherichia coli (EHEC) are zoonotic pathogens transmitted to humans through contaminated water or bovine products. One of the strategies used by pathogenic bacteria to survive in aquatic environments is using free-living amoebae as hosts. Acanthamoeba castellanii is an amoeba known to host several waterborne pathogens. This study investigates the survival of EHEC with A. castellanii, which could contribute to its spread and transmission to humans. We used a gentamicin protection assay as well as fluorescence and electron microscopy to monitor the intra-amoebae survival of EHEC O157:H7 over 24 h. The results showed that EHEC were able to survive within A. castellanii and that this survival was reduced by Shiga toxins (Stx) produced by EHEC. A toxic effect mediated by Stx was demonstrated by amoebae mortality and LDH release during co-culture of EHEC and amoeba. This work describes the ability of EHEC to survive within A. castellanii, and this host-pathogen interaction is partially controlled by the Stx. Thus, this ubiquitous amoeba could represent an environmental niche for EHEC survival and transmission.

  4. Rapid determination of antibiotic resistance in E. coli using dielectrophoresis

    NASA Astrophysics Data System (ADS)

    Hoettges, Kai F.; Dale, Jeremy W.; Hughes, Michael P.

    2007-09-01

    In recent years, infections due to antibiotic-resistant strains of bacteria such as methillicin-resistant Staphylococcus aureus and ciprofloxacin-resistant Escherichia coli are on the rise, and with them the demand for rapid antibiotic testing is also rising. Conventional tests, such as disc diffusion testing, require a primary sample to be tested in the presence of a number of antibiotics to verify which antibiotics suppress growth, which take approximately 24 h to complete and potentially place the patient at severe risk. In this paper we describe the use of dielectrophoresis as a rapid marker of cell death, by detecting changes in the electrophysiology of the cell caused by the administration of an antibiotic. In contrast to other markers, the electrophysiology of the cell changes rapidly during cell death allowing live cells to be distinguished from dead (or dying) cells without the need for culturing. Using polymyxin B as an example antibiotic, our studies indicate that significant changes in cell characteristics can be observed as soon as 1 h passes after isolating a culture from nutrient broth.

  5. Chromosome Replication in Escherichia coli: Life on the Scales

    PubMed Central

    Norris, Vic; Amar, Patrick

    2012-01-01

    At all levels of Life, systems evolve on the 'scales of equilibria'. At the level of bacteria, the individual cell must favor one of two opposing strategies and either take risks to grow or avoid risks to survive. It has been proposed in the Dualism hypothesis that the growth and survival strategies depend on non-equilibrium and equilibrium hyperstructures, respectively. It has been further proposed that the cell cycle itself is the way cells manage to balance the ratios of these types of hyperstructure so as to achieve the compromise solution of living on the two scales. Here, we attempt to re-interpret a major event, the initiation of chromosome replication in Escherichia coli, in the light of scales of equilibria. This entails thinking in terms of hyperstructures as responsible for intensity sensing and quantity sensing and how this sensing might help explain the role of the DnaA protein in initiation of replication. We outline experiments and an automaton approach to the cell cycle that should test and refine the scales concept. PMID:25371267

  6. Solvent isotope effect on macromolecular dynamics in E. coli.

    PubMed

    Jasnin, Marion; Tehei, Moeava; Moulin, Martine; Haertlein, Michael; Zaccai, Giuseppe

    2008-06-01

    Elastic incoherent neutron scattering was used to explore solvent isotope effects on average macromolecular dynamics in vivo. Measurements were performed on living E. coli bacteria containing H2O and D2O, respectively, close to physiological conditions of temperature. Global macromolecular flexibility, expressed as mean square fluctuation (MSF) values, and structural resilience in a free energy potential, expressed as a mean effective force constant, [Symbol: see text]k'[Symbol: see text], were extracted in the two solvent conditions. They referred to the average contribution of all macromolecules inside the cell, mostly dominated by the internal motions of the protein fraction. Flexibility and resilience were both found to be smaller in D2O than in H2O. A difference was expected because the driving forces behind macromolecular stabilization and dynamics are different in H2O and D2O. In D2O, the hydrophobic effect is known to be stronger than in H2O: it favours the burial of non-polar surfaces as well as their van der Waals' packing in the macromolecule cores. This may lead to the observed smaller MSF values. In contrast, in H2O, macromolecules would present more water-exposed surfaces, which would give rise to larger MSF values, in particular at the macromolecular surface. The smaller [Symbol: see text]k'[Symbol: see text] value suggested a larger entropy content in the D2O case due to increased sampling of macromolecular conformational substates.

  7. Serum Antibodies Protect against Intraperitoneal Challenge with Enterotoxigenic Escherichia coli

    PubMed Central

    Yang, Xinghong; Thornburg, Theresa; Holderness, Kathryn; Suo, Zhiyong; Cao, Ling; Lim, Timothy; Avci, Recep; Pascual, David W.

    2011-01-01

    To assess whether anticolonization factor antigen I (CFA/I) fimbriae antibodies (Abs) from enterotoxigenic Escherichia coli (ETEC) can protect against various routes of challenge, BALB/c mice were immunized with a live attenuated Salmonella vaccine vector expressing CFA/I fimbriae. Vaccinated mice elicited elevated systemic IgG and mucosal IgA Abs, unlike mice immunized with the empty Salmonella vector. Mice were challenged with wild-type ETEC by the oral, intranasal (i.n.), and intraperitoneal (i.p.) routes. Naïve mice did not succumb to oral challenge, but did to i.n. challenge, as did immunized mice; however, vaccinated mice were protected against i.p. ETEC challenge. Two intramuscular (i.m.) immunizations with CFA/I fimbriae without adjuvant conferred 100% protection against i.p. ETEC challenge, while a single 30 μg dose conferred 88% protection. Bactericidal assays showed that ETEC is highly sensitive to anti-CFA/I sera. These results suggest that parenteral immunization with purified CFA/I fimbriae can induce protective Abs and may represent an alternative method to elicit protective Abs for passive immunity to ETEC. PMID:22007145

  8. Theory of optimal information transmission in E. coli chemotaxis pathway

    NASA Astrophysics Data System (ADS)

    Micali, Gabriele; Endres, Robert G.

    Bacteria live in complex microenvironments where they need to make critical decisions fast and reliably. These decisions are inherently affected by noise at all levels of the signaling pathway, and cells are often modeled as an input-output device that transmits extracellular stimuli (input) to internal proteins (channel), which determine the final behavior (output). Increasing the amount of transmitted information between input and output allows cells to better infer extracellular stimuli and respond accordingly. However, in contrast to electronic devices, the separation into input, channel, and output is not always clear in biological systems. Output might feed back into the input, and the channel, made by proteins, normally interacts with the input. Furthermore, a biological channel is affected by mutations and can change under evolutionary pressure. Here, we present a novel approach to maximize information transmission: given cell-external and internal noise, we analytically identify both input distributions and input-output relations that optimally transmit information. Using E. coli chemotaxis as an example, we conclude that its pathway is compatible with an optimal information transmission device despite the ultrasensitive rotary motors.

  9. Fluorescent antibody-viability staining and beta-glucuronidase assay as rapid methods for monitoring Escherichia coli viability in coastal marine waters.

    PubMed

    Caruso, G; De Pasquale, F; Mancuso, M; Zampino, D; Crisafi, E

    2006-01-01

    A faecal pollution monitoring of coastal Messina waters was performed by comparing three (microscopic, enzyme, and culture) methods. Evidence of Escherichia coli cells (29.99 to 96.79% of the total enteropathogenic serotypes) retaining their viability into the marine environment was shown. beta-Glucuronidase activity rates suggested that living cells were also metabolically active. Heavily polluted sites were detected, where improperly treated urban wastes were discharged. Significant relationships between microscopic and enzymatic data proved both methods to be suitable alternatives to the culture method for E. coli detection, improving environmental quality assessment.

  10. Assessment of human exposure to 3rd generation cephalosporin resistant E. coli (CREC) through consumption of broiler meat in Belgium.

    PubMed

    Depoorter, P; Persoons, D; Uyttendaele, M; Butaye, P; De Zutter, L; Dierick, K; Herman, L; Imberechts, H; Van Huffel, X; Dewulf, J

    2012-09-17

    Acquired resistance of Escherichia coli to 3rd generation cephalosporin antimicrobials is a relevant issue in intensive broiler farming. In Belgium, about 35% of the E. coli strains isolated from live broilers are resistant to 3rd generation cephalosporins while over 60% of the broilers are found to be carrier of these 3rd generation cephalosporin resistant E. coli (CREC) after selective isolation. A model aimed at estimating the exposure of the consumer to CREC by consumption of broiler meat was elaborated. This model consists of different modules that simulate the farm to fork chain starting from primary production, over slaughter, processing and distribution to storage, preparation and consumption of broiler meat. Input data were obtained from the Belgian Food Safety agencies' annual monitoring plan and results from dedicated research programs or surveys. The outcome of the model using the available baseline data estimates that the probability of exposure to 1000 colony forming units (cfu) of CREC or more during consumption of a meal containing chicken meat is ca. 1.5%, the majority of exposure being caused by cross contamination in the kitchen. The proportion of CREC (within the total number of E. coli) at primary production and the overall contamination of broiler carcasses or broiler parts with E. coli are dominant factors in the consumer exposure to CREC. The risk of this exposure for human health cannot be estimated at this stage given a lack of understanding of the factors influencing the transfer of cephalosporin antimicrobial resistance genes from these E. coli to the human intestinal bacteria and data on the further consequences of the presence of CREC on human health. Copyright © 2012 Elsevier B.V. All rights reserved.

  11. Exacerbation of murine ileitis by Toll‐like receptor 4 mediated sensing of lipopolysaccharide from commensal Escherichia coli

    PubMed Central

    Heimesaat, M M; Fischer, A; Jahn, H‐K; Niebergall, J; Freudenberg, M; Blaut, M; Liesenfeld, O; Schumann, R R; Göbel, U B; Bereswill, S

    2007-01-01

    Background In the course of inflammatory bowel diseases (IBD) and acute murine ileitis following peroral Toxoplasma gondii infection, commensal Escherichia coli accumulate at inflamed mucosal sites and aggravate small intestinal immunopathology. Aim To unravel the molecular mechanisms by which commensal E coli exacerbate ileitis. Methods Ileitis was investigated in mice that lack Toll‐like receptors (TLR) 2 or 4, specific for bacterial lipoproteins (LP) or lipopolysaccharide (LPS), respectively. Gnotobiotic mice, in which any cultivable gut bacteria were eradicated by antibiotic treatment, were used to study the role of LPS in ileitis. Results Microbiological analyses revealed that E coli increase in the inflamed ileum. TLR4−/−, but not TLR2−/−, mice displayed reduced mortality and small intestinal immunopathology. Decreased interferon (IFN)‐γ and nitric oxide (NO) levels in the inflamed terminal ileum of TLR4−/− mice indicated that TLR4 signalling aggravates ileitis via local mediator release from immune cells. E coli strains isolated from the inflamed ileum activated cultured mouse macrophages and induced TLR4‐dependent nuclear factor κB activation and NO production in human embryonic kidney 293 cells and in peritoneal macrophages, respectively. Most strikingly, in contrast with wild‐type mice, gnotobiotic TLR4−/− mice were protected from induction of ileitis by treatment with purified E coli lipid A or colonisation with live E coli. Finally, prophylactic treatment with the LPS scavenger polymyxin B ameliorated T gondii‐induced ileitis. Conclusion These findings highlight the innate immune system as a key player in T gondii‐induced ileal immunopathology. Treatment with LPS or TLR4 antagonists may represent a novel strategy for prophylaxis and/or therapy of small intestinal inflammation in IBD. PMID:17255219

  12. Comparative proteomic analysis of differentially expressed proteins in the earthworm Eisenia fetida during Escherichia coli O157:H7 stress.

    PubMed

    Wang, Xing; Chang, Li; Sun, Zhenjun; Zhang, Yufeng

    2010-12-03

    Escherichia coli O157:H7 is an intestine-inhabiting bacterium associated with many severe disease outbreaks worldwide. It may enter the soil environment with the excreta of infected animals (e.g., horses, cattle, chickens) and humans. Earthworms can protect themselves against invading pathogens because of their efficient innate defense system. Identification of differential proteomic responses to E. coli O157:H7 may provide a better understanding of the survival mechanisms of the earthworm Eisenia fetida that lives in E. coli O157:H7-polluted environments. Whole earthworm extracts, collected at days 7, 14, 21, and 28 after E. coli O157:H7 stress, were analyzed by two-dimensional gel electrophoresis and quantitative image analysis. In total, 124 proteins demonstrated significant regulation at least at one time point, and 52 proteins were identified by matrix-assisted laser desorption/ionization-tandem time-of-flight mass spectrometry and database searching. Compared with control samples, 11 protein spots were up-regulated and 41 were down-regulated for at least one time point. The identified proteins, including heat shock protein 90, fibrinolytic protease 0, gelsolin-like protein, lombricine kinase, coelomic cytolytic factor-1, manganous superoxide dismutase, catalase, triosephosphate isomerase, extracellular globin-4, lysenin, intermediate filament protein, and glyceraldehyde-3-phosphate dehydrogenase, are involved in several processes, including transcription, translation, the tricarboxylic acid cycle, and the glucose metabolic process. Thus, our study provides a functional profile of the E. coli O157:H7-responsive proteins in earthworms. We suggest that the variable levels and trends in these spots on the gel may be useful as biomarker profiles to investigate E. coli O157:H7 contamination levels in soils.

  13. Detection of Escherichia coli enterotoxins in stools.

    PubMed Central

    Merson, M H; Yolken, R H; Sack, R B; Froehlich, J L; Greenberg, H B; Huq, I; Black, R W

    1980-01-01

    We determined whether enterotoxigenic Escherichia coli diarrhea could be diagnosed by direct examination of stools for heat-labile (LT) and heat-stable (ST) enterotoxins. The Y-1 adrenal cell and an enzyme-linked immunosorbent assay (ELISA) detected LT in 85 and 93%, respectively, of stool specimens obtained from adults with acute diarrhea from whom an LT- and ST-producing organism had been isolated. Furthermore, the ELISA assay detected LT in 8 of 35 stool specimens from which no LT-producing E. coli had been isolated. The infant mouse assay was utilized to detect ST in these stool specimens and was found to be an insensitive method, showing positive results in only 36% of the specimens from which an ST-producing organism was isolated. Further studies are warranted to determine the diagnostic value of direct detection of LT in stools, especially by the ELISA method. PMID:6995331

  14. Production of recombinant avidin in Escherichia coli.

    PubMed

    Airenne, K J; Sarkkinen, P; Punnonen, E L; Kulomaa, M S

    1994-06-24

    A recombinant avidin (re-Avd), containing amino acids (aa) 1-123 of the native chicken egg-white Avd, was produced in Escherichia coli. When cells were grown at 37 degrees C production was over 1 microgram/ml, due to altering the codon preference of the first ten codons. The re-Avd was recovered as a soluble protein from cells grown at 25 or 30 degrees C, whereas at 37 degrees C it was mostly insoluble in inclusion bodies. Our results indicated that, despite the potentially harmful biotin-binding activity of Avd, it is possible to produce biologically active Avd in E. coli which then can easily be purified by affinity chromatography on a biotin column in a single step.

  15. Automatic tracking of Escherichia coli bacteria.

    PubMed

    Xie, Jun; Khan, Shahid; Shah, Mubarak

    2008-01-01

    In this paper, we present an automatic method for estimating the trajectories of Escherichia coli bacteria from in vivo phase-contrast microscopy videos. To address the low-contrast boundaries in cellular images, an adaptive kernel-based technique is applied to detect cells in sequence of frames. Then a novel matching gain measure is introduced to cope with the challenges such as dramatic changes of cells' appearance and serious overlapping and occlusion. For multiple cell tracking, an optimal matching strategy is proposed to improve the handling of cell collision and broken trajectories. The results of successful tracking of Escherichia coli from various phase-contrast sequences are reported and compared with manually-determined trajectories, as well as those obtained from existing tracking methods. The stability of the algorithm with different parameter values is also analyzed and discussed.

  16. Engineering ethanologenic Escherichia coli for levoglucosan utilization.

    PubMed

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

    2011-09-01

    Levoglucosan is a major product of biomass pyrolysis. While this pyrolyzed biomass, also known as bio-oil, contains sugars that are an attractive fermentation substrate, commonly-used biocatalysts, such as Escherichia coli, lack the ability to metabolize this anhydrosugar. It has previously been shown that recombinant expression of the levoglucosan kinase enzyme enables use of levoglucosan as carbon and energy source. Here, ethanologenic E. coli KO11 was engineered for levoglucosan utilization by recombinant expression of levoglucosan kinase from Lipomyces starkeyi. Our engineering strategy uses a codon-optimized gene that has been chromosomally integrated within the pyruvate to ethanol (PET) operon and does not require additional antibiotics or inducers. Not only does this engineered strain use levoglucosan as sole carbon source, but it also ferments levoglucosan to ethanol. This work demonstrates that existing biocatalysts can be easily modified for levoglucosan utilization. Copyright © 2011 Elsevier Ltd. All rights reserved.

  17. ELECTRON MICROSCOPY OF PLASMOLYSIS IN ESCHERICHIA COLI.

    PubMed

    COTA-ROBLES, E H

    1963-03-01

    Cota-Robles, Eugene H. (University of California, Riverside). Electron microscopy of plasmolysis in Escherichia coli. J. Bacteriol. 85:499-503. 1963.-Escherichia coli cells plasmolyzed in 0.35 m sucrose reveal plasmolysis at one tip of a cell or in the center of dividing cells in which protoplast partition has been complete. Central plasmolysis reveals that protoplast separation can be completed before the invagination of the cell wall is complete. These studies support the concept that these cells divide by constriction. The strength of the union between cell wall and cytoplasm is not uniform around the entire cell. It is strongest along the sides of these rod-shaped cells and weakest at one tip of the single cell. Thus, a single cell generally forms one cup-shaped vacuole in which the cytoplasm has collapsed away from one tip of the cell.

  18. ELECTRON MICROSCOPY OF PLASMOLYSIS IN ESCHERICHIA COLI

    PubMed Central

    Cota-Robles, Eugene H.

    1963-01-01

    Cota-Robles, Eugene H. (University of California, Riverside). Electron microscopy of plasmolysis in Escherichia coli. J. Bacteriol. 85:499–503. 1963.—Escherichia coli cells plasmolyzed in 0.35 m sucrose reveal plasmolysis at one tip of a cell or in the center of dividing cells in which protoplast partition has been complete. Central plasmolysis reveals that protoplast separation can be completed before the invagination of the cell wall is complete. These studies support the concept that these cells divide by constriction. The strength of the union between cell wall and cytoplasm is not uniform around the entire cell. It is strongest along the sides of these rod-shaped cells and weakest at one tip of the single cell. Thus, a single cell generally forms one cup-shaped vacuole in which the cytoplasm has collapsed away from one tip of the cell. Images PMID:14042923

  19. Designed phosphoprotein recognition in Escherichia coli.

    PubMed

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

    2014-11-21

    Protein phosphorylation is a central biological mechanism for cellular adaptation to environmental changes. Dysregulation of phosphorylation signaling is implicated in a wide variety of diseases. Thus, the ability to detect and quantify protein phosphorylation is highly desirable for both diagnostic and research applications. Here we present a general strategy for detecting phosphopeptide-protein interactions in Escherichia coli. We first redesign a model tetratricopeptide repeat (TPR) protein to recognize phosphoserine in a sequence-specific fashion and characterize the interaction with its target phosphopeptide in vitro. We then combine in vivo site-specific incorporation of phosphoserine with split mCherry assembly to observe the designed phosphopeptide-protein interaction specificity in E. coli. This in vivo strategy for detecting and characterizing phosphopeptide-protein interactions has numerous potential applications for the study of natural interactions and the design of novel ones.

  20. 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.