The Capsule Supports Survival but Not Traversal of Escherichia coli K1 across the Blood-Brain Barrier

OpenAIRE

Hoffman, Jill A.; Wass, Carol; Stins, Monique F.; Kim, Kwang Sik

1999-01-01

The vast majority of cases of gram-negative meningitis in neonates are caused by K1-encapsulated Escherichia coli. The role of the K1 capsule in the pathogenesis of E. coli meningitis was examined with an in vivo model of experimental hematogenous E. coli K1 meningitis and an in vitro model of the blood-brain barrier. Bacteremia was induced in neonatal rats with the E. coli K1 strain C5 (O18:K1) or its K1− derivative, C5ME. Subsequently, blood and cerebrospinal fluid (CSF) were obtained for c...

Two proline porters in Escherichia coli K-12.

Science.gov (United States)

Stalmach, M E; Grothe, S; Wood, J M

1983-11-01

Escherichia coli mutants defective at putP and putA lack proline transport via proline porter I and proline dehydrogenase activity, respectively. They retain a proline uptake system (proline porter II) that is induced during tryptophan-limited growth and are sensitive to the toxic L-proline analog, 3,4-dehydroproline. 3,4-Dehydroproline-resistant mutants derived from a putP putA mutant lack proline porter II. Auxotrophic derivatives derived from putP+ or putP bacteria can grow if provided with proline at low concentration (25 microM); those derived from the 3,4-dehydroproline-resistant mutants require high proline for growth (2.5 mM). We conclude that E. coli, like Salmonella typhimurium, possesses a second proline porter that is inactivated by mutations at the proP locus.

Effects of paraquat on Escherichia coli: Differences between B and K-12 strains

International Nuclear Information System (INIS)

Kitzler, J.W.; Minakami, H.; Fridovich, I.

1990-01-01

Escherichia coli B and K-12 are equally susceptible to the bacteriostatic effects of aerobic paraquat, but they differed strikingly when the lethality of paraquat was evaluated. E. coli B suffered an apparent loss of viability when briefly exposed to paraquat, whereas E. coli K-12 did not. This difference depended on the ability of the B-strain, but not the K-12 strain, to retain internalized paraquat; the B strain was killed on aerobic tryptic soy-yeast extract plates during the incubation which preceded the counting of colonies. This difference in retention of paraquat between strains was demonstrated by delayed loss of viability, by growth inhibition, and by cyanide-resistant respiration after brief exposure to paraquat, washing, and testing in fresh medium. This difference was also shown by using [ 14 C]paraquat. This previously unrecognized difference between E. coli B and K-12 has been the cause of apparently contradictory reports and should lead to some reevaluation of the pertinent literature

The K1 capsule is the critical determinant in the development of Escherichia coli meningitis in the rat.

OpenAIRE

Kim, K S; Itabashi, H; Gemski, P; Sadoff, J; Warren, R L; Cross, A S

1992-01-01

Although Escherichia coli strains possessing the K1 capsule are predominant among isolates from neonatal E. coli meningitis and most of these K1 isolates are associated with a limited number of 0 lipopolysaccharide (LPS) types, the basis of this association of K1 and certain 0 antigens with neonatal E. coli meningitis is not clear. The present study examined in experimental E. coli bacteremia and meningitis in newborn and adult rats whether or not the K1 capsule and/or O-LPS antigen are criti...

A structural study of the capsular antigens of Escherichia coli K36 and Klebsiella K68

International Nuclear Information System (INIS)

Stanley, S.M.R.

1986-01-01

This thesis discusses the structural study of the capsular antigens of the bacteria, Escherichia coli K36 and Klebsiella K68. In the elucidation of bacterial polysaccharides chemically based analytical procedures and instrumental analytical techniques were used. Nuclear magnetic resonance is a powerful tool for obtaining structural information on poly-, oligo- and di-saccharides and a detailed discussion of this technique, and the results obtained in this study, is given

Increased Frequency of ColV Plasmids and Mannose-Resistant Hemagglutinating Activity in an Escherichia coli K1 Population

OpenAIRE

1984-01-01

The expression of traits linked to pathogenicity was studied in a population of Escherichia coli K1 strains. It was found that E. coli K1 strains isolated from extraintestinal infection harbor the ColV plasmid and express mannose-resistant hemagglutinating activity type VI with a high frequency. The presence of these properties may play a role in the ability of some E. coli K1 serogroups to invade.

The detection of K88, K99 fimbrial antigen and enterotoxin genes of Escherichia coli isolated from piglets and calves with diarrhoea in Indonesia

Directory of Open Access Journals (Sweden)

Supar

1996-03-01

Full Text Available Enterotoxigenic Escherichia coli (ETEC strains cause diarrhoeal disease in piglets and calves in Indonesia. These strains possess two virulence factors namely attachment and enterotoxin antigens . These factors could be detected phenotypically and genetically. Haemolytic Escherichia coli (E coli isolates possessing K88 fimbrial antigen associated with 0-group 108 and 149. They were positive for K88 gene and demonstrated their ability to produce heat labile enterotoxin (LT and genetically were all positive for LT gene . Seventeen isolates ofE coli K88 which associated with 0-group 149 were positive forSTb gene, other O-serotypes were negative . Ten isolates of Ecoli K88 which associated with 0-group 108 possessed K88, K99, LT and STa genes, but negative for STb gene . However, phenotypically the K99 antigen and STa toxin were not expressed under laboratory conditions, the reason was not well understood . E. coli K99 strains isolated from calves wit h diarrhoea were all associated with 0-group 9 and produced STa toxin when tested by suckling mousse bioassay. The E. coli K99 calf isolates were all hybridized with K99 and STa gene only . It is likely that K99 gene is associated with STa gene . The DNA hybridization technique is more convenience to be used for confirmation diagnosis of colibacillosis, however, not all veterinary laboratories could perform these tests .

Restriction alleviation of phage λ in Escherichia Coli K-12 cells after γ-irradiation

International Nuclear Information System (INIS)

Rabinkova, E.V.; Torosyan, M.V.; Fradkin, G.E.

1987-01-01

In γ-irradiated cells of Escherichia coli K-12 restriction allevation of an unmodified phage λ is only observed in AB1157 strain. No restriction allevation by γ-rays is registered in AB1157 mutants (rec A and ssb-1)

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

DEFF Research Database (Denmark)

Jørgensen, Steffen L; Kudirkiene, Egle; Li, Lili

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 econo...

Probiotic Mixture Golden Bifido Prevents Neonatal Escherichia coli K1 Translocation via Enhancing Intestinal Defense

Directory of Open Access Journals (Sweden)

Qing Zeng

2017-09-01

Full Text Available Escherichia coli (E. coli K1 sepsis and meningitis is a severe infection characterized by high mortality in neonates. Successful colonization and translocation across the intestinal mucosa have been regarded as the critical steps for E. coli K1 sepsis and meningitis. We recently reported that the probiotic mixture, Golden Bifido (containing live Lactobacillus bulgaricus, Bifidobacterium, and Streptococcus thermophilus, LBS has a preventive role against neonatal E. coli K1 bacteremia and meningitis. However, the interaction between the neonatal gut barrier, probiotics and E. coli K1 is still not elucidated. The present study aims to investigate how LBS exerts its protective effects on neonatal gut barrier during E. coli K1 infection. The beneficial effects of LBS were explored in vitro and in vivo using human colon carcinoma cell lines HT-29 and rat model of neonatal E. coli K1 infection, respectively. Our results showed that stimulation with E. coli K1 was able to cause intestinal barrier dysfunction, which were reflected by E. coli K1-induced intestinal damage and apoptosis of intestinal epithelial cells, reduction of mucin, immunoglobulin A (IgA and tight junction proteins expression, as well as increase in intestinal permeability, all these changes facilitate E. coli K1 intestinal translocation. However, these changes were alleviated when HT-29 cells were treated with LBS before E. coli K1 infection. Furthermore, we found that LBS-treated neonatal rats (without E. coli K1 infection have showed higher production of mucin, ZO-1, IgA, Ki67 in intestinal mucosa as well as lower intestinal permeability than that of non-treated rats, indicating that LBS could accelerate the development of neonatal intestinal defense. Taken together, our results suggest that enhancement of the neonatal intestinal defense to fight against E. coli K1 translocation could be the potential mechanism to elucidate how LBS confers a protective effect against neonatal E

Crystallization of the FaeE chaperone of Escherichia coli F4 fimbriae

International Nuclear Information System (INIS)

Van Molle, Inge; Buts, Lieven; Coppens, Fanny; Qiang, Liu; Wyns, Lode; Loris, Remy; Bouckaert, Julie; De Greve, Henri

2005-01-01

The periplasmic chaperone FaeE of E. coli F4 fimbriae crystallizes in three crystal forms. F4 (formerly K88) fimbriae from enterotoxigenic Escherichia coli are assembled via the FaeE/FaeD chaperone/usher pathway. The chaperone FaeE crystallizes in three crystal forms, all belonging to space group C2. Crystals of form 1 diffract to 2.3 Å and have unit-cell parameters a = 195.7, b = 78.5, c = 184.6 Å, β = 102.2°. X-ray data for crystal form 2 were collected to 2.7 Å using an SeMet variant of FaeE. The crystals have unit-cell parameters a = 136.4, b = 75.7, c = 69.4 Å, β = 92.8°. Crystals of form 3 were formed in a solution containing the FaeE–FaeG complex and diffract to 2.8 Å. Unit-cell parameters are a = 109.7, b = 78.6, c = 87.8 Å, β = 96.4°

Crystallization of the FaeE chaperone of Escherichia coli F4 fimbriae

Energy Technology Data Exchange (ETDEWEB)

Van Molle, Inge, E-mail: ivmolle@vub.ac.be; Buts, Lieven; Coppens, Fanny; Qiang, Liu; Wyns, Lode; Loris, Remy; Bouckaert, Julie; De Greve, Henri [Laboratorium voor Ultrastructuur, Vlaams Interuniversitair Instituut voor Biotechnologie, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussel (Belgium)

2005-04-01

The periplasmic chaperone FaeE of E. coli F4 fimbriae crystallizes in three crystal forms. F4 (formerly K88) fimbriae from enterotoxigenic Escherichia coli are assembled via the FaeE/FaeD chaperone/usher pathway. The chaperone FaeE crystallizes in three crystal forms, all belonging to space group C2. Crystals of form 1 diffract to 2.3 Å and have unit-cell parameters a = 195.7, b = 78.5, c = 184.6 Å, β = 102.2°. X-ray data for crystal form 2 were collected to 2.7 Å using an SeMet variant of FaeE. The crystals have unit-cell parameters a = 136.4, b = 75.7, c = 69.4 Å, β = 92.8°. Crystals of form 3 were formed in a solution containing the FaeE–FaeG complex and diffract to 2.8 Å. Unit-cell parameters are a = 109.7, b = 78.6, c = 87.8 Å, β = 96.4°.

The EcoCyc database: reflecting new knowledge about Escherichia coli K-12.

Science.gov (United States)

Keseler, Ingrid M; Mackie, Amanda; Santos-Zavaleta, Alberto; Billington, Richard; Bonavides-Martínez, César; Caspi, Ron; Fulcher, Carol; Gama-Castro, Socorro; Kothari, Anamika; Krummenacker, Markus; Latendresse, Mario; Muñiz-Rascado, Luis; Ong, Quang; Paley, Suzanne; Peralta-Gil, Martin; Subhraveti, Pallavi; Velázquez-Ramírez, David A; Weaver, Daniel; Collado-Vides, Julio; Paulsen, Ian; Karp, Peter D

2017-01-04

EcoCyc (EcoCyc.org) is a freely accessible, comprehensive database that collects and summarizes experimental data for Escherichia coli K-12, the best-studied bacterial model organism. New experimental discoveries about gene products, their function and regulation, new metabolic pathways, enzymes and cofactors are regularly added to EcoCyc. New SmartTable tools allow users to browse collections of related EcoCyc content. SmartTables can also serve as repositories for user- or curator-generated lists. EcoCyc now supports running and modifying E. coli metabolic models directly on the EcoCyc website. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

Genes and proteins of Escherichia coli K-12.

Science.gov (United States)

Riley, M

1998-01-01

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

[Virulence markers of Escherichia coli O1 strains].

Science.gov (United States)

Makarova, M A; Kaftyreva, L A; Grigor'eva, N S; Kicha, E V; Lipatova, L A

2011-01-01

To detect virulence genes in clinical isolates of Escherichia coli O1 using polymerase chain reaction (PCR). One hundred and twenty strains of E.coli O1 strains isolated from faeces of patients with acute diarrhea (n = 45) and healthy persons (n = 75) were studied. PCR with primers for rfb and fliC genes, which control synthesis of O- and H- antigens respectively, was used. Fourteen virulence genes (pap, aaf, sfa, afa, eaeA, bfpA, ial, hly, cnf, stx1, stx2, lt, st, and aer) were detected by PCR primers. K1-antigen was determined by Pastorex Meningo B/E. coli O1 kit (Bio-Rad). rfb gene controlling O-antigen synthesis in serogroup O1 as well as fliC gene controlling synthesis of H7 and K1 antigens were detected in all strains. Thus all E. coli strains had antigenic structure O1:K1 :H-:F7. Virulence genes aafl, sfa, afa, eaeA, bfpA, ial, hly, cnf, stx1, stx2, lt, and st were not detected. All strains owned pap and aer genes regardless of the presence of acute diarrhea symptoms. It was shown that E. coli O1:KI:H-:F7 strains do not have virulence genes which are characteristic for diarrhea-causing Escherichia. In accordance with the presence of pap and aer genes they could be attributed to uropathogenic Escherichia (UPEC) or avian-pathogenic Escherichia (APEC). It is necessary to detect virulence factors in order to determine E. coli as a cause of intestinal infection.

Phylogenetische und funktionelle Analysen zur Kapsel O-Acetyltransferase NeuO von Escherichia coli K1

OpenAIRE

Mordhorst, Ines Louise

2010-01-01

Escherichia coli ist ein Kommensale des menschlichen und tierischen Gastrointestinaltraktes. Einige E. coli-Stämme sind in der Lage, extraintestinale Erkrankungen beim Menschen wie Harnwegsinfekte, Neugeborenen-Meningitis und Sepsis, sowie beim Tier aviäre Coliseptikämien, hervorzurufen. Ein wichtiger Virulenzfaktor des Bakteriums ist dabei die aus α-2,8-verknüpften Sialinsäuremonomeren aufgebaute K1-Kapsel, die phasenvariabel mit einer hohen Frequenz O-acetyliert werden kann. Im Jahr 20...

NarK is a nitrite-extrusion system involved in anaerobic nitrate respiration by Escherichia coli

NARCIS (Netherlands)

Rowe, John J.; Ubbink-Kok, Trees; Molenaar, Douwe; Konings, Wilhelmus; Driessen, Arnold J.M.

Escherichia coli can use nitrate as a terminal electron acceptor for anaerobic respiration. A polytopic membrane protein, termed NarK, has been implicated in nitrate uptake and nitrite excretion and is thought to function as a nitrate/nitrite antiporter. The longest-lived radioactive isotope of

Genetic diversity of K-antigen gene clusters of Escherichia coli and their molecular typing using a suspension array.

Science.gov (United States)

Yang, Shuang; Xi, Daoyi; Jing, Fuyi; Kong, Deju; Wu, Junli; Feng, Lu; Cao, Boyang; Wang, Lei

2018-04-01

Capsular polysaccharides (CPSs), or K-antigens, are the major surface antigens of Escherichia coli. More than 80 serologically unique K-antigens are classified into 4 groups (Groups 1-4) of capsules. Groups 1 and 4 contain the Wzy-dependent polymerization pathway and the gene clusters are in the order galF to gnd; Groups 2 and 3 contain the ABC-transporter-dependent pathway and the gene clusters consist of 3 regions, regions 1, 2 and 3. Little is known about the variations among the gene clusters. In this study, 9 serotypes of K-antigen gene clusters (K2ab, K11, K20, K24, K38, K84, K92, K96, and K102) were sequenced and correlated with their CPS chemical structures. On the basis of sequence data, a K-antigen-specific suspension array that detects 10 distinct CPSs, including the above 9 CPSs plus K30, was developed. This is the first report to catalog the genetic features of E. coli K-antigen variations and to develop a suspension array for their molecular typing. The method has a number of advantages over traditional bacteriophage and serum agglutination methods and lays the foundation for straightforward identification and detection of additional K-antigens in the future.

Global impact of mature biofilm lifestyle on Escherichia coli K-12 gene expression

DEFF Research Database (Denmark)

Beloin, C.; Valle, J.; Latour-Lambert, P.

2004-01-01

The formation of biofilm results in a major lifestyle switch that is thought to affect the expression of multiple genes and operons. We used DNA arrays to study the global effect of biofilm formation on gene expression in mature Escherichia coli K-12 biofilm. We show that, when biofilm is compared...... that 20 of these genes are required for the formation of mature biofilm. This group includes 11 genes of previously unknown function. These results constitute a comprehensive analysis of the global transcriptional response triggered in mature E. coli biofilms and provide insights into its physiological...

Biogenic synthesis and characterization of gold nanoparticles by Escherichia coli K12 and its heterogeneous catalysis in degradation of 4-nitrophenol

Science.gov (United States)

Srivastava, Sarvesh Kumar; Yamada, Ryosuke; Ogino, Chiaki; Kondo, Akihiko

2013-02-01

Room-temperature extracellular biosynthesis of gold nanoparticles (Au NPs) was achieved using Escherichia coli K12 cells without the addition of growth media, pH adjustments or inclusion of electron donors/stabilizing agents. The resulting nanoparticles were analysed by ultraviolet-visible (UV-vis) spectrophotometry, atomic force microscopy, transmission electron microscopy and X-ray diffraction. Highly dispersed gold nanoplates were achieved in the order of around 50 nm. Further, the underlying mechanism was found to be controlled by certain extracellular membrane-bound proteins, which was confirmed by Fourier transformation-infrared spectroscopy and sodium dodecyl sulfate polyacrylamide gel electrophoresis. We observed that certain membrane-bound peptides are responsible for reduction and subsequent stabilization of Au NPs (confirmed by zeta potential analysis). Upon de-activation of these proteins, no nanoparticle formation was observed. Also, we prepared a novel biocatalyst with Au NPs attached to the membrane-bound fraction of E. coli K12 cells serving as an efficient heterogeneous catalyst in complete reduction of 4-nitrophenol in the presence of NaBH4 which was studied with UV-vis spectroscopy. This is the first report on bacterial membrane-Au NP nanobiocomposite serving as an efficient heterogeneous catalyst in complete reduction of nitroaromatic pollutant in water.

Escherichia coli K-12 pathogenicity in the pea aphid, Acyrthosiphon pisum, reveals reduced antibacterial defense in aphids.

Science.gov (United States)

Altincicek, Boran; Ter Braak, Bas; Laughton, Alice M; Udekwu, Klas I; Gerardo, Nicole M

2011-10-01

To better understand the molecular basis underlying aphid immune tolerance to beneficial bacteria and immune defense to pathogenic bacteria, we characterized how the pea aphid Acyrthosiphon pisum responds to Escherichia coli K-12 infections. E. coli bacteria, usually cleared in the hemolymph of other insect species, were capable of growing exponentially and killing aphids within a few days. Red fluorescence protein expressing E. coli K-12 laboratory strain multiplied in the aphid hemolymph as well as in the digestive tract, resulting in death of infected aphids. Selected gene deletion mutants of the E. coli K-12 predicted to have reduced virulence during systemic infections showed no difference in either replication or killing rate when compared to the wild type E. coli strain. Of note, however, the XL1-Blue E. coli K-12 strain exhibited a significant lag phase before multiplying and killing aphids. This bacterial strain has recently been shown to be more sensitive to oxidative stress than other E. coli K-12 strains, revealing a potential role for reactive oxygen species-mediated defenses in the otherwise reduced aphid immune system. Copyright © 2011 Elsevier Ltd. All rights reserved.

GenoBase: comprehensive resource database of Escherichia coli K-12.

Science.gov (United States)

Otsuka, Yuta; Muto, Ai; Takeuchi, Rikiya; Okada, Chihiro; Ishikawa, Motokazu; Nakamura, Koichiro; Yamamoto, Natsuko; Dose, Hitomi; Nakahigashi, Kenji; Tanishima, Shigeki; Suharnan, Sivasundaram; Nomura, Wataru; Nakayashiki, Toru; Aref, Walid G; Bochner, Barry R; Conway, Tyrrell; Gribskov, Michael; Kihara, Daisuke; Rudd, Kenneth E; Tohsato, Yukako; Wanner, Barry L; Mori, Hirotada

2015-01-01

Comprehensive experimental resources, such as ORFeome clone libraries and deletion mutant collections, are fundamental tools for elucidation of gene function. Data sets by omics analysis using these resources provide key information for functional analysis, modeling and simulation both in individual and systematic approaches. With the long-term goal of complete understanding of a cell, we have over the past decade created a variety of clone and mutant sets for functional genomics studies of Escherichia coli K-12. We have made these experimental resources freely available to the academic community worldwide. Accordingly, these resources have now been used in numerous investigations of a multitude of cell processes. Quality control is extremely important for evaluating results generated by these resources. Because the annotation has been changed since 2005, which we originally used for the construction, we have updated these genomic resources accordingly. Here, we describe GenoBase (http://ecoli.naist.jp/GB/), which contains key information about comprehensive experimental resources of E. coli K-12, their quality control and several omics data sets generated using these resources. © The Author(s) 2014. Published by Oxford University Press on behalf of Nucleic Acids Research.

The Escherichia coli argW-dsdCXA genetic island is highly variable, and E. coli K1 strains commonly possess two copies of dsdCXA.

Science.gov (United States)

Moritz, Rebecca L; Welch, Rodney A

2006-11-01

The genome sequences of Escherichia coli pathotypes reveal extensive genetic variability in the argW-dsdCXA island. Interestingly, the archetype E. coli K1 neonatal meningitis strain, strain RS218, has two copies of the dsdCXA genes for d-serine utilization at the argW and leuX islands. Because the human brain contains d-serine, an epidemiological study emphasizing K1 isolates surveyed the dsdCXA copy number and function. Forty of 41 (97.5%) independent E. coli K1 isolates could utilize d-serine. Southern blot hybridization revealed physical variability within the argW-dsdC region, even among 22 E. coli O18:K1:H7 isolates. In addition, 30 of 41 K1 strains, including 21 of 22 O18:K1:H7 isolates, had two dsdCXA loci. Mutational analysis indicated that each of the dsdA genes is functional in a rifampin-resistant mutant of RS218, mutant E44. The high percentage of K1 strains that can use d-serine is in striking contrast to our previous observation that only 4 of 74 (5%) isolates in the diarrheagenic E. coli (DEC) collection have this activity. The genome sequence of diarrheagenic E. coli isolates indicates that the csrRAKB genes for sucrose utilization are often substituted for dsdC and a portion of dsdX present at the argW-dsdCXA island of extraintestinal isolates. Among DEC isolates there is a reciprocal pattern of sucrose fermentation versus d-serine utilization. The ability to use d-serine is a trait strongly selected for among E. coli K1 strains, which have the ability to infect a wide range of extraintestinal sites. Conversely, diarrheagenic E. coli pathotypes appear to have substituted sucrose for d-serine as a potential nutrient.

Lactobacillus rhamnosus GG supernatant enhance neonatal resistance to systemic Escherichia coli K1 infection by accelerating development of intestinal defense

OpenAIRE

Xiaolong He; Qing Zeng; Santhosh Puthiyakunnon; Zhijie Zeng; Weijun Yang; Jiawen Qiu; Lei Du; Swapna Boddu; Tongwei Wu; Danxian Cai; Sheng-He Huang; Hong Cao

2017-01-01

The objective of this study was to determine whether Lactobacillus rhamnosus GG culture supernatant (LCS) has a preventive effect against gut-derived systemic neonatal Escherichia coli (E. coli) K1 infection. The preventive effects were evaluated in human colonic carcinoma cell line Caco-2 and neonatal rat models. Our in vitro results showed that LCS could block adhesion, invasion and translocation of E. coli K1 to Caco-2 monolayer via up-regulating mucin production and maintaining intestinal...

Polyamine stress at high pH in Escherichia coli K-12

Directory of Open Access Journals (Sweden)

Tate Daniel P

2005-10-01

Full Text Available Abstract Background Polyamines such as spermine and spermidine are required for growth of Escherichia coli; they interact with nucleic acids, and they bind to ribosomes. Polyamines block porins and decrease membrane permeability, activities that may protect cells in acid. At high concentrations, however, polyamines impair growth. They impair growth more severely at high pH, probably due to their increased uptake as membrane-permeant weak bases. The role of pH is critical in understanding polyamine stress. Results The effect of polyamines was tested on survival of Escherichia coli K-12 W3110 in extreme acid or base (pH conditions outside the growth range. At pH 2, 10 mM spermine increased survival by 2-fold, and putrescine increased survival by 30%. At pH 9.8, however, E. coli survival was decreased 100-fold by 10 mM spermine, putrescine, cadaverine, or spermidine. At pH 8.5, spermine decreased the growth rate substantially, whereas little effect was seen at pH 5.5. Spermidine required ten-fold higher concentrations to impair growth. On proteomic 2-D gels, spermine and spermidine caused differential expression of 31 different proteins. During log-phase growth at pH 7.0, 1 mM spermine induced eight proteins, including PykF, GlpK, SerS, DeaD, OmpC and OmpF. Proteins repressed included acetate-inducible enzymes (YfiD, Pta, Lpd as well as RapA (HepA, and FabB. At pH 8.5, spermine induced additional proteins: TnaA, OmpA, YrdA and NanA (YhcJ and also repressed 17 proteins. Four of the proteins that spermine induced (GlpK, OmpA, OmpF, TnaA and five that were repressed (Lpd, Pta, SucB, TpiA, YfiD show similar induction or repression, respectively, in base compared to acid. Most of these base stress proteins were also regulated by spermidine, but only at ten-fold higher concentration (10 mM at high pH (pH 8.5. Conclusion Polyamines increase survival in extreme acid, but decrease E. coli survival in extreme base. Growth inhibition by spermine and

Physiological Function of Rac Prophage During Biofilm Formation and Regulation of Rac Excision in Escherichia coli K-12

Science.gov (United States)

including Escherichia coli, Salmonella spp. and Shigellaspp. Here, we found that rac excision is induced during biofilm formation, and the isogenic...stain without rac is more motile and forms more biofilms in nutrient-rich medium at early stages in E.coli K-12. Additionally, the presence of rac...genes increases cell lysis during biofilm development. In most E. coli strains, rac is integrated into the ttcA gene which encodes a tRNA-thioltransferase

Global forecast of antimicrobial resistance in invasive isolates of Escherichia coli and Klebsiella pneumoniae.

Science.gov (United States)

Alvarez-Uria, Gerardo; Gandra, Sumanth; Mandal, Siddhartha; Laxminarayan, Ramanan

2018-03-01

To project future antimicrobial resistance (AMR) in Escherichia coli and Klebsiella pneumoniae. Mixed linear models were constructed from a sample of countries with AMR data in the ResistanceMap database. Inverse probability weighting methods were used to account for countries without AMR data. The estimated prevalence of AMR in 2015 was 64.5% (95% confidence interval (CI) 42-87%) for third-generation cephalosporin-resistant (3GCR) Escherichia coli, 5.8% (95% CI 1.8-9.7%) for carbapenem-resistant (CR) E. coli, 66.9% (95% CI 47.1-86.8%) for 3GCR Klebsiella pneumoniae, and 23.4% (95% CI 7.4-39.4%) for CR K. pneumoniae. The projected AMR prevalence in 2030 was 77% (95% CI 55-99.1%) for 3GCR E. coli, 11.8% (95% CI 3.7-19.9%) for CR E. coli, 58.2% (95% CI 50.2-66.1%) for 3GCR K. pneumoniae, and 52.8% (95% CI 16.3-89.3%) for CR K. pneumoniae. The models suggest that third-generation cephalosporins and carbapenems could be ineffective against a sizeable proportion of infections by E. coli and K. pneumoniae in most parts of the world by 2030, supporting both the need to enhance stewardship efforts and to prioritize research and development of new antibiotics for resistant Enterobacteriaceae. Copyright © 2018 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Inhibition of Inducible Nitric Oxide Controls Pathogen Load and Brain Damage by Enhancing Phagocytosis of Escherichia coli K1 in Neonatal Meningitis

OpenAIRE

Mittal, Rahul; Gonzalez-Gomez, Ignacio; Goth, Kerstin A.; Prasadarao, Nemani V.

2010-01-01

Escherichia coli K1 is a leading cause of neonatal meningitis in humans. In this study, we sought to determine the pathophysiologic relevance of inducible nitric oxide (iNOS) in experimental E. coli K1 meningitis. By using a newborn mouse model of meningitis, we demonstrate that E. coli infection triggered the expression of iNOS in the brains of mice. Additionally, iNOS−/− mice were resistant to E. coli K1 infection, displaying normal brain histology, no bacteremia, no disruption of the blood...

Tif-stimulated deoxyribonucleic acid repair in Escherichia coli K-12

International Nuclear Information System (INIS)

Castellazzi, M.; Jacques, M.; George, J.

1980-01-01

Bacterial survival is significantly increased after ultraviolet irradiation in tif sfi cells, provided that the thermosensitive tif mutation has been expressed at 41 0 C before irradiation. This tif-mediated reactivation of ultraviolet irradiated bacteria needs de novo protein synthesis, as is the case for the tif-mediated reactivation of ultraviolet-irradiated phage lambda. However, in striking contrast to the phage reactivation process, this tif-mediated reactivation is no longer associated with mutagenesis. It also requires the presence of the uvrA + excision function. These results strongly suggest the existence in Escherichia coli K-12 of a repair pathway acting on bacterial deoxyribonucleic acid which is inducible, error free, and uvr dependent

Escherichia coli pathotypes

Science.gov (United States)

Escherichia coli strains are important commensals of the intestinal tract of humans and animals; however, pathogenic strains, including diarrhea-inducing E. coli and extraintestinal pathogenic E. coli. Intestinal E. coli pathotypes may cause a dehydrating watery diarrhea, or more severe diseases su...

GENETIC CONTROL OF RESTRICTION AND MODIFICATION IN ESCHERICHIA COLI1

Science.gov (United States)

Boyer, Herbert

1964-01-01

Boyer, Herbert (Yale University, New Haven, Conn.). Genetic control of restriction and modification in Escherichia coli. J. Bacteriol. 88:1652–1660. 1964.—Bacterial crosses with K-12 strains of Escherichia coli as Hfr donors (Hfr Hayes, Hfr Cavalli, and Hfr P4X-6) and B/r strains of E. coli as F− recipients were found to differ from crosses between K-12 Hfr donors and K-12 F− recipients in two ways: (i) recombinants (leu, pro, lac, and gal) did not appear at discrete time intervals but did appear simultaneously 30 min after matings were initiated, and (ii) the linkage of unselected markers to selected markers was reduced. Integration of a genetic region linked to the threonine locus of K-12 into the B/r genome resulted in a hybrid which no longer gave anomalous results in conjugation experiments. A similar region of the B strain was introduced into the K-12 strain, which then behaved as a typical B F− recipient. These observations are interpreted as the manifestation of host-controlled modification and restriction on the E. coli chromosome. This was verified by experiments on the restriction and modification of the bacteriophage lambda, F-lac, F-gal, and sex-factor, F1. It was found that the genetic region that controlled the mating responses of the K-12 and B/r strains also controlled the modification and restriction properties of these two strains. The genes responsible for the restricting and modifying properties of the K-12 and B strains of E. coli were found to be allelic, linked to each other, and linked to the threonine locus. PMID:14240953

Regulatory role of XynR (YagI) in catabolism of xylonate in Escherichia coli K-12.

Science.gov (United States)

Shimada, Tomohiro; Momiyama, Eri; Yamanaka, Yuki; Watanabe, Hiroki; Yamamoto, Kaneyoshi; Ishihama, Akira

2017-12-01

The genome of Escherichia coli K-12 contains ten cryptic phages, altogether constituting about 3.6% of the genome in sequence. Among more than 200 predicted genes in these cryptic phages, 14 putative transcription factor (TF) genes exist, but their regulatory functions remain unidentified. As an initial attempt to make a breakthrough for understanding the regulatory roles of cryptic phage-encoded TFs, we tried to identify the regulatory function of CP4-6 cryptic prophage-encoded YagI with unknown function. After SELEX screening, YagI was found to bind mainly at a single site within the spacer of bidirectional transcription units, yagA (encoding another uncharacterized TF) and yagEF (encoding 2-keto-3-deoxy gluconate aldolase, and dehydratase, respectively) within this prophage region. YagEF enzymes are involved in the catabolism of xylose downstream from xylonate. We then designated YagI as XynR (regulator of xylonate catabolism), one of the rare single-target TFs. In agreement with this predicted regulatory function, the activity of XynR was suggested to be controlled by xylonate. Even though low-affinity binding sites of XynR were identified in the E. coli K-12 genome, they all were inside open reading frames, implying that the regulation network of XynR is still fixed within the CR4-6 prophage without significant influence over the host E. coli K-12. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

ANIMAL ENTEROTOXIGENIC ESCHERICHIA COLI

Science.gov (United States)

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

The absence of the luxS gene increases swimming motility and flagella synthesis in Escherichia coli K12

International Nuclear Information System (INIS)

Ling, Hua; Kang, Aram; Tan, Mui Hua; Qi, Xiaobao; Chang, Matthew Wook

2010-01-01

Research highlights: → This paper provides the first evidence that luxS deletion enhances swimming motility and flagella synthesis in Escherichia coli K12 based on motility, transcriptome, and scanning electron microscopy analyses. → A conceptual genetic regulatory network underlying the increased flagella synthesis was constructed based on the transcriptome and network component analyses, and previously known regulatory relations. → The genetic regulatory network suggests that the increased flagella synthesis and motility might be contributed to by increased flhDC transcription level and/or decreased c-di-GMP concentration in luxS-deficient E. coli. -- Abstract: Despite the significant role of S-ribosylhomocysteinase (LuxS) in the activated methyl cycle pathway and quorum sensing, the connectivity between luxS and other cellular functions remains incomplete. Herein, we show that luxS deletion significantly increases swimming motility and flagella synthesis in Escherichia coli K12 using motility, transcriptome, and scanning electron microscopy assays. Further, based on the transcriptome and network component analyses, and known regulatory relations, we propose a conceptual genetic regulatory network underlying the increased flagella synthesis in response to luxS deletion.

The absence of the luxS gene increases swimming motility and flagella synthesis in Escherichia coli K12

Energy Technology Data Exchange (ETDEWEB)

Ling, Hua; Kang, Aram; Tan, Mui Hua; Qi, Xiaobao [School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637459 (Singapore); Chang, Matthew Wook, E-mail: Matthewchang@ntu.edu.sg [School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637459 (Singapore)

2010-10-29

Research highlights: {yields} This paper provides the first evidence that luxS deletion enhances swimming motility and flagella synthesis in Escherichia coli K12 based on motility, transcriptome, and scanning electron microscopy analyses. {yields} A conceptual genetic regulatory network underlying the increased flagella synthesis was constructed based on the transcriptome and network component analyses, and previously known regulatory relations. {yields} The genetic regulatory network suggests that the increased flagella synthesis and motility might be contributed to by increased flhDC transcription level and/or decreased c-di-GMP concentration in luxS-deficient E. coli. -- Abstract: Despite the significant role of S-ribosylhomocysteinase (LuxS) in the activated methyl cycle pathway and quorum sensing, the connectivity between luxS and other cellular functions remains incomplete. Herein, we show that luxS deletion significantly increases swimming motility and flagella synthesis in Escherichia coli K12 using motility, transcriptome, and scanning electron microscopy assays. Further, based on the transcriptome and network component analyses, and known regulatory relations, we propose a conceptual genetic regulatory network underlying the increased flagella synthesis in response to luxS deletion.

Hyperproduction of poly(4-hydroxybutyrate) from glucose by recombinant Escherichia coli

DEFF Research Database (Denmark)

Zhou, Xiao-Yun; Yuan, Xiao-Xi; Shi, Zhen-Yu

2012-01-01

inactivated to enhance the carbon flux to poly(4HB) biosynthesis. Four PHA binding proteins (PhaP or phasins) including PhaP1, PhaP2, PhaP3 and PhaP4 from R. eutropha were heterologously expressed in the recombinant E. coli, respectively, leading to different levels of improvement in poly(4HB) production......-hydroxybutyrate or 1,4-butanediol (1,4-BD) are provided as precursor which are much more expensive than glucose. At present, high production cost is a big obstacle for large scale production of poly(4HB). RESULTS: Recombinant Escherichia coli strain was constructed to achieve hyperproduction of poly(4....... Among them PhaP1 exhibited the highest capability for enhanced polymer synthesis. The recombinant E. coli produced 5.5 g L(-1) cell dry weight containing 35.4% poly(4HB) using glucose as a sole carbon source in a 48 h shake flask growth. In a 6-L fermentor study, 11.5 g L(-1) cell dry weight containing...

Genetical and functional investigation of fliC genes encoding flagellar serotype H4 in wildtype strains of Escherichia coli and in a laboratory E. coli K-12 strain expressing flagellar antigen type H48

Directory of Open Access Journals (Sweden)

Schaudinn Christoph

2005-01-01

Full Text Available Abstract Background Serotyping of O-(lipopolysaccharide and H-(flagellar antigens is a wideley used method for identification of pathogenic strains and clones of Escherichia coli. At present, 176 O- and 53 H-antigens are described for E. coli which occur in different combinations in the strains. The flagellar antigen H4 is widely present in E. coli strains of different O-serotypes and pathotypes and we have investigated the genetic relationship between H4 encoding fliC genes by PCR, nucleotide sequencing and expression studies. Results The complete nucleotide sequence of fliC genes present in E. coli reference strains U9-41 (O2:K1:H4 and P12b (O15:H17 was determined and both were found 99.3% (1043 of 1050 nucleotides identical in their coding sequence. A PCR/RFLP protocol was developed for typing of fliC-H4 strains and 88 E. coli strains reacting with H4 antiserum were investigated. Nucleotide sequencing of complete fliC genes of six E. coli strains which were selected based on serum agglutination titers, fliC-PCR genotyping and reference data revealed 96.6 to 100% identity on the amino acid level. The functional expression of flagellin encoded by fliC-H4 from strain U9-41 and from our strain P12b which is an H4 expressing variant type was investigated in the E. coli K-12 strain JM109 which encodes flagellar type H48. The fliC recombinant plasmid carrying JM109 strains reacted with both H4 and H48 specific antisera whereas JM109 reacted only with the H48 antiserum. By immunoelectron microscopy, we could show that the flagella made by the fliC-H4 recombinant plasmid carrying strain are constituted of H48 and H4 flagellins which are co-assembled into functional flagella. Conclusion The flagellar serotype H4 is encoded by closely related fliC genes present in serologically different types of E. coli strainswhich were isolated at different time periods and geographical locations. Our expression studies show for the first time, that flagellins of

Porcine aminopeptidase N binds to F4+ enterotoxigenic Escherichia coli fimbriae.

Science.gov (United States)

Xia, Pengpeng; Wang, Yiting; Zhu, Congrui; Zou, Yajie; Yang, Ying; Liu, Wei; Hardwidge, Philip R; Zhu, Guoqiang

2016-02-09

F4(+) enterotoxigenic Escherichia coli (ETEC) strains cause diarrheal disease in neonatal and post-weaned piglets. Several different host receptors for F4 fimbriae have been described, with porcine aminopeptidase N (APN) reported most recently. The FaeG subunit is essential for the binding of the three F4 variants to host cells. Here we show in both yeast two-hybrid and pulldown assays that APN binds directly to FaeG, the major subunit of F4 fimbriae, from three serotypes of F4(+) ETEC. Modulating APN gene expression in IPEC-J2 cells affected ETEC adherence. Antibodies raised against APN or F4 fimbriae both reduced ETEC adherence. Thus, APN mediates the attachment of F4(+) E. coli to intestinal epithelial cells.

Respiration shutoff in Escherichia coli K12 strains is induced by far ultraviolet radiations and by mitomycin C

International Nuclear Information System (INIS)

Swenson, P.A.; Norton, I.L.

1984-01-01

Near ultraviolet radiations (UV) cause respiration to shutoff in Escherichia coli B/r. It has been reported that E. coli K12 strains do not shut off respiration after UV. It is also reported that mitomycin C did not cause this 'SOS' response. In this paper it is reported that higher UV fluences than were previously used will cause respiration shutoff in K12 strain W3110 and that cyclic AMP increases the sensitivity of respiration shutoff of irradiated cell suspensions. Also mitomycin C shuts off respiration in this strain. Neither UV nor mitomycin C causes respiration shutoff in the recA56 derivative of W3110. Thus respiration shutoff is a recA dependent response to UV and mitomycin C in E. coli K12 strains. (Auth.)

Norwegian patients and retail chicken meat share cephalosporin-resistant Escherichia coli and IncK/blaCMY-2 resistance plasmids.

Science.gov (United States)

Berg, E S; Wester, A L; Ahrenfeldt, J; Mo, S S; Slettemeås, J S; Steinbakk, M; Samuelsen, Ø; Grude, N; Simonsen, G S; Løhr, I H; Jørgensen, S B; Tofteland, S; Lund, O; Dahle, U R; Sunde, M

2017-06-01

In 2012 and 2014 the Norwegian monitoring programme for antimicrobial resistance in the veterinary and food production sectors (NORM-VET) showed that 124 of a total of 406 samples (31%) of Norwegian retail chicken meat were contaminated with extended-spectrum cephalosporin-resistant Escherichia coli. The aim of this study was to compare selected cephalosporin-resistant E. coli from humans and poultry to determine their genetic relatedness based on whole genome sequencing (WGS). Escherichia coli representing three prevalent cephalosporin-resistant multi-locus sequence types (STs) isolated from poultry (n=17) were selected from the NORM-VET strain collections. All strains carried an IncK plasmid with a bla CMY-2 gene. Clinical E. coli isolates (n=284) with AmpC-mediated resistance were collected at Norwegian microbiology laboratories from 2010 to 2014. PCR screening showed that 29 of the clinical isolates harboured both IncK and bla CMY-2 . All IncK/bla CMY-2 -positive isolates were analysed with WGS-based bioinformatics tools. Analysis of single nucleotide polymorphisms (SNP) in 2.5 Mbp of shared genome sequences showed close relationship, with fewer than 15 SNP differences between five clinical isolates from urinary tract infections (UTIs) and the ST38 isolates from poultry. Furthermore, all of the 29 clinical isolates harboured IncK/bla CMY-2 plasmid variants highly similar to the IncK/bla CMY-2 plasmid present in the poultry isolates. Our results provide support for the hypothesis that clonal transfer of cephalosporin-resistant E. coli from chicken meat to humans may occur, and may cause difficult-to-treat infections. Furthermore, these E. coli can be a source of AmpC-resistance plasmids for opportunistic pathogens in the human microbiota. Copyright © 2017 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

The steady-state kinetics of the NADH-dependent nitrite reductase from Escherichia coli K 12. Nitrite and hydroxylamine reduction.

OpenAIRE

Jackson, R H; Cole, J A; Cornish-Bowden, A

1981-01-01

The reduction of both NO2- and hydroxylamine by the NADH-dependent nitrite reductase of Escherichia coli K 12 (EC 1.6.6.4) appears to follow Michaelis-Menten kinetics over a wide range of NADH concentrations. Substrate inhibition can, however, be detected at low concentrations of the product NAD+. In addition, NAD+ displays mixed product inhibition with respect to NADH and mixed or uncompetitive inhibition with respect to hydroxylamine. These inhibition characteristics are consistent with a m...

Enterohemorrhagic Escherichia coli (EHEC

Directory of Open Access Journals (Sweden)

Abdullah Kilic

2011-08-01

Full Text Available Escherichia coli is a bacterium that is commonly found in the gut of humans and warm-blooded animals. Most strains of E. coli are harmless for human. E. coli O157:H7 is the most common member of a group of pathogenic E. coli strains known variously as enterohaemorrhagic, verocytotoxin-producing, or Shiga-toxin-producing organisms. EHEC bacterium is the major cause of haemorrhagic colitis and haemolytic uraemic syndrome. The reservoir of this pathogen appears to be mainly cattle and other ruminants such as camels. It is transmitted to humans primarily through consumption of contaminated foods. [TAF Prev Med Bull 2011; 10(4.000: 387-388

Experimental validation of the predicted binding site of Escherichia coli K1 outer membrane protein A to human brain microvascular endothelial cells: identification of critical mutations that prevent E. coli meningitis.

Science.gov (United States)

Pascal, Tod A; Abrol, Ravinder; Mittal, Rahul; Wang, Ying; Prasadarao, Nemani V; Goddard, William A

2010-11-26

Escherichia coli K1, the most common cause of meningitis in neonates, has been shown to interact with GlcNAc1-4GlcNAc epitopes of Ecgp96 on human brain microvascular endothelial cells (HBMECs) via OmpA (outer membrane protein A). However, the precise domains of extracellular loops of OmpA interacting with the chitobiose epitopes have not been elucidated. We report the loop-barrel model of these OmpA interactions with the carbohydrate moieties of Ecgp96 predicted from molecular modeling. To test this model experimentally, we generated E. coli K1 strains expressing OmpA with mutations of residues predicted to be critical for interaction with the HBMEC and tested E. coli invasion efficiency. For these same mutations, we predicted the interaction free energies (including explicit calculation of the entropy) from molecular dynamics (MD), finding excellent correlation (R(2) = 90%) with experimental invasion efficiency. Particularly important is that mutating specific residues in loops 1, 2, and 4 to alanines resulted in significant inhibition of E. coli K1 invasion in HBMECs, which is consistent with the complete lack of binding found in the MD simulations for these two cases. These studies suggest that inhibition of the interactions of these residues of Loop 1, 2, and 4 with Ecgp96 could provide a therapeutic strategy to prevent neonatal meningitis due to E. coli K1.

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

Directory of Open Access Journals (Sweden)

Ancuta Mihaela Rotar

2013-11-01

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

The type III secretion system is involved in the invasion and intracellular survival of Escherichia coli K1 in human brain microvascular endothelial cells

OpenAIRE

Yao, Yufeng; Xie, Yi; Perace, Donna; Zhong, Yi; Lu, Jie; Tao, Jing; Guo, Xiaokui; Kim, Kwang Sik

2009-01-01

Type III secretion systems have been documented in many Gram-negative bacteria, including enterohemorrhagic Escherichia coli. We have previously shown the existence of a putative type III secretion system in meningitis-causing E. coli K1 strains, referred to as E. coli type III secretion 2 (ETT2). The sequence of ETT2 in meningitis-causing E. coli K1 strain EC10 (O7:K1) revealed that ETT2 comprises the epr, epa and eiv genes, but bears mutations, deletions and insertions. We constructed the E...

Effect of gama irradiation (Co60 in the control of Enterococci spp. and Escherichia coli in chilled chicken (Gallus gallus heart

Directory of Open Access Journals (Sweden)

Marta Maria Braga Batista Soares Xavier

2016-09-01

Full Text Available The present study aimed to evaluate the efficiency of the irradiation process in the control of Enterococci spp. and Escherichia coli in chilled chicken heart samples acquired in an industry located in the West Zone of Rio de Janeiro, Brazil, using irradiation doses of 1.5 kGy, 3, 0 kGy and 4.5 kGy. These microorganisms are related to fecal contamination, and are indicators of the sanitary processing conditions of the foodstuffs. The bacteriological analyses were conducted applying the methodologies and standards recommended by Brazilian norms resolution no. 12 (BRASIL, 2001 and instruction no. 62 (BRASIL, 2003 Regarding Escherichia coli, no statistically significant difference among the four groups (control, 1.5 kGy, 3.0 kGy and 4.5 kGy was observed (p> 0.05. The Most Probable Number (MPN for Enterococci spp. was not proven in the investigated samples. Thus, the Co60 gamma irradiation process was effective in eliminating Escherichia coli, and the lowest dose, of 1.5 kGy, was enough to abolish this enteropathogen from the evaluated samples.

Synthesis of avenanthramides using engineered Escherichia coli.

Science.gov (United States)

Lee, Su Jin; Sim, Geun Young; Kang, Hyunook; Yeo, Won Seok; Kim, Bong-Gyu; Ahn, Joong-Hoon

2018-03-22

Hydroxycinnamoyl anthranilates, also known as avenanthramides (avns), are a group of phenolic alkaloids with anti-inflammatory, antioxidant, anti-itch, anti-irritant, and antiatherogenic activities. Some avenanthramides (avn A-H and avn K) are conjugates of hydroxycinnamic acids (HC), including p-coumaric acid, caffeic acid, and ferulic acid, and anthranilate derivatives, including anthranilate, 4-hydroxyanthranilate, and 5-hydroxyanthranilate. Avns are primarily found in oat grain, in which they were originally designated as phytoalexins. Knowledge of the avns biosynthesis pathway has now made it possible to synthesize avns through a genetic engineering strategy, which would help to further elucidate their properties and exploit their beneficial biological activities. The aim of the present study was to synthesize natural avns in Escherichia coli to serve as a valuable resource. We synthesized nine avns in E. coli. We first synthesized avn D from glucose in E. coli harboring tyrosine ammonia lyase (TAL), 4-coumarate:coenzyme A ligase (4CL), anthranilate N-hydroxycinnamoyl/benzoyltransferase (HCBT), and anthranilate synthase (trpEG). A trpD deletion mutant was used to increase the amount of anthranilate in E. coli. After optimizing the incubation temperature and cell density, approximately 317.2 mg/L of avn D was synthesized. Avn E and avn F were then synthesized from avn D, using either E. coli harboring HpaBC and SOMT9 or E. coli harboring HapBC alone, respectively. Avn A and avn G were synthesized by feeding 5-hydroxyanthranilate or 4-hydroxyanthranilate to E. coli harboring TAL, 4CL, and HCBT. Avn B, avn C, avn H, and avn K were synthesized from avn A or avn G, using the same approach employed for the synthesis of avn E and avn F from avn D. Using different HCs, nine avns were synthesized, three of which (avn D, avn E, and avn F) were synthesized from glucose in E. coli. These diverse avns provide a strategy to synthesize both natural and unnatural avns

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

Science.gov (United States)

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 .

21 CFR 866.3255 - Escherichia coli serological reagents.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 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...

Leaner and meaner genomes in Escherichia coli

DEFF Research Database (Denmark)

Ussery, David

2006-01-01

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

Radiation inactivation of Salmonella panama and Escherichia coli K 12 present on deep-frozen broiler carcasses

International Nuclear Information System (INIS)

Mulder, R.W.A.W.

1976-01-01

Low doses of ionizing radiation have been used to extend the shelf life of refrigerated poultry carcasses and to reduce the numbers of Salmonellae present. This report gives results of experiments on irradiation of deep-frozen poultry carcasses which were, before freezing, artificially contaminated with Salmonella panama and with a nalidixic acid-resistant Escherichia coli K 12. The D-values (decimal reduction) obtained with the inoculated carcasses were compared with D-values obtained with carcasses which were slaughtered in the normal way. The D-values for S.panama and for E.coli K 12 were 64.9 krad and 55.9 krad in the dripwater. Under commercial conditions approximately 100 krad were required for one decimal reduction of the Enterobacteriaceae present. The D-values estimated on the skin were higher for S.panama than for E.coli K 12 (128.6 krad vs 57.6 krad). If it is assumed that 1 positive carcass in 10,000 is allowed, the deep-frozen carcasses should be irradiated with doses of at least 700 krad to be sure of the absence of the tested S.panama strain. (orig.) [de

Radiation inactivation of Salmonella panama and Escherichia coli K 12 present on deep-frozen broiler carcasses

Energy Technology Data Exchange (ETDEWEB)

Mulder, R W.A.W. [Spelderholt Inst. for Poultry Research, Beekbergen (Netherlands). Processing Dept.

1976-01-01

Low doses of ionizing radiation have been used to extend the shelf life of refrigerated poultry carcasses and to reduce the numbers of Salmonellae present. This report gives results of experiments on irradiation of deep-frozen poultry carcasses which were, before freezing, artificially contaminated with Salmonella panama and with a nalidixic acid-resistant Escherichia coli K 12. The D-values (decimal reduction) obtained with the inoculated carcasses were compared with D-values obtained with carcasses which were slaughtered in the normal way. The D-values for S.panama and for E.coli K 12 were 64.9 krad and 55.9 krad in the dripwater. Under commercial conditions approximately 100 krad were required for one decimal reduction of the Enterobacteriaceae present. The D-values estimated on the skin were higher for S.panama than for E.coli K 12 (128.6 krad vs 57.6 krad). If it is assumed that 1 positive carcass in 10,000 is allowed, the deep-frozen carcasses should be irradiated with doses of at least 700 krad to be sure of the absence of the tested S.panama strain.

Construction of Escherichia coli K-12 in-frame, single-gene knockout mutants: the Keio collection.

Science.gov (United States)

Baba, Tomoya; Ara, Takeshi; Hasegawa, Miki; Takai, Yuki; Okumura, Yoshiko; Baba, Miki; Datsenko, Kirill A; Tomita, Masaru; Wanner, Barry L; Mori, Hirotada

2006-01-01

We have systematically made a set of precisely defined, single-gene deletions of all nonessential genes in Escherichia coli K-12. Open-reading frame coding regions were replaced with a kanamycin cassette flanked by FLP recognition target sites by using a one-step method for inactivation of chromosomal genes and primers designed to create in-frame deletions upon excision of the resistance cassette. Of 4288 genes targeted, mutants were obtained for 3985. To alleviate problems encountered in high-throughput studies, two independent mutants were saved for every deleted gene. These mutants-the 'Keio collection'-provide a new resource not only for systematic analyses of unknown gene functions and gene regulatory networks but also for genome-wide testing of mutational effects in a common strain background, E. coli K-12 BW25113. We were unable to disrupt 303 genes, including 37 of unknown function, which are candidates for essential genes. Distribution is being handled via GenoBase (http://ecoli.aist-nara.ac.jp/).

Associations of Escherichia coli K-12 OmpF trimers with rough and smooth lipopolysaccharides

International Nuclear Information System (INIS)

Diedrich, D.L.; Stein, M.A.; Schnaitman, C.A.

1990-01-01

The associations of both rough and smooth lipopolysaccharides (LPS) with the OmpF porin of Escherichia coli K-12 were examined in galE strains deleted for ompC. Transformation with pSS37 and growth with galactose conferred the ability to assemble a Shigella dysenteriae O antigen onto the core oligosaccharide of E. coli K-12 LPS. The association of LPS with OmpF trimers was assessed by staining, autoradiography of LPS specifically labeled with [1-14C]galactose, and Western immunoblotting with a monoclonal antibody specific for OmpF trimers. These techniques revealed that the migration distances and multiple banding patterns of OmpF porin trimers in sodium dodecyl sulfate-polyacrylamide gels were dictated by the chemotype of associated LPS. Expression of smooth LPS caused almost all of the trimeric OmpF to run in gels with a slower mobility than trimers from rough strains. The LPS associated with trimers from a smooth strain differed from the bulk-phase LPS by consisting almost exclusively of molecules with O antigen

The polymeric stability of the Escherichia coli F4 (K88) fimbriae enhances its mucosal immunogenicity following oral immunization.

Science.gov (United States)

Verdonck, Frank; Joensuu, Jussi Joonas; Stuyven, Edith; De Meyer, Julie; Muilu, Mikko; Pirhonen, Minna; Goddeeris, Bruno Maria; Mast, Jan; Niklander-Teeri, Viola; Cox, Eric

2008-10-23

Only a few vaccines are commercially available against intestinal infections since the induction of a protective intestinal immune response is difficult to achieve. For instance, oral administration of most proteins results in oral tolerance instead of an antigen-specific immune response. We have shown before that as a result of oral immunization of piglets with F4 fimbriae purified from pathogenic enterotoxigenic Escherichia coli (ETEC), the fimbriae bind to the F4 receptor (F4R) in the intestine and induce a protective F4-specific immune response. F4 fimbriae are very stable polymeric structures composed of some minor subunits and a major subunit FaeG that is also the fimbrial adhesin. In the present study, the mutagenesis experiments identified FaeG amino acids 97 (N to K) and 201 (I to V) as determinants for F4 polymeric stability. The interaction between the FaeG subunits in mutant F4 fimbriae is reduced but both mutant and wild type fimbriae behaved identically in F4R binding and showed equal stability in the gastro-intestinal lumen. Oral immunization experiments indicated that a higher degree of polymerisation of the fimbriae in the intestine was correlated with a better F4-specific mucosal immunogenicity. These data suggest that the mucosal immunogenicity of soluble virulence factors can be increased by the construction of stable polymeric structures and therefore help in the development of effective mucosal vaccines.

The absence of caffeine inhibition of post-replication repair in excision deficient strains of Escherichia coli B and K12

International Nuclear Information System (INIS)

McCulley, C.M.; Johnson, R.C.

1976-01-01

The effect of caffeine on postreplication repair, as seen in alkaline sucrose gradients, conjugation, and ultraviolet light (UV) survival, was studied in excision deficient strains of Escherichia coli K12 and B. A caffeine concentration of 2 mg/ml was chosen for the study which did not inhibit colony formation. Both E. coli K12 AB2500 and E. coli B WWP2 were more sensitive to UV when plated on caffeine plates. Conjugation was not inhibited in the E. coli K12 strain; however, the same procedure confirmed caffeine inhibition in the E. coli B strain. Caffeine did not inhibit postreplication repair in either strain, as determined by sedimentation profile studies of DNA on alkaline sucrose gradients. No strand breakage or degradation was observed in parental or post-UV replicated DNA for as long as 50 min incubation in caffeine. Thus caffeine concentrations that inhibited two recA gene product related phenomena did not cause immediate changes in size of DNA or inhibit the rate of a DNA gap generating postreplication type of DNA repair

Nonthermal inactivation of Escherichia coli K12 in buffered peptone water using a pilot-plant scale supercritical carbon dioxide system with gas-liquid porous metal contractor

Science.gov (United States)

This study evaluated the effectiveness of a supercritical carbon dioxide (SCCO2) system, with a gas-liquid CO2 contactor, for reducing Escherichia coli K12 in diluted buffered peptone water. 0.1% (w/v) buffered peptone water inoculated with E. coli K12 was processed using the SCCO2 system at CO2 con...

Inhibition of Apoptosis by Escherichia coli K1 Is Accompanied by Increased Expression of BclXL and Blockade of Mitochondrial Cytochrome c Release in Macrophages

OpenAIRE

Sukumaran, Sunil K.; Selvaraj, Suresh K.; Prasadarao, Nemani V.

2004-01-01

Escherichia coli K1 survival in the blood is a critical step for the onset of meningitis in neonates. Therefore, the circulating bacteria are impelled to avoid host defense mechanisms by finding a niche to survive and multiply. Our recent studies have shown that E. coli K1 enters and survives in both monocytes and macrophages in the newborn rat model of meningitis as well as in macrophage cell lines. Here we demonstrate that E. coli K1 not only extends the survival of human and murine infecte...

Multiplex polymerase chain reaction for identification of Escherichia coli, Escherichia albertii and Escherichia fergusonii.

Science.gov (United States)

Lindsey, Rebecca L; Garcia-Toledo, L; Fasulo, D; Gladney, L M; Strockbine, N

2017-09-01

Escherichia coli, Escherichia albertii, and Escherichia fergusonii are closely related bacteria that can cause illness in humans, such as bacteremia, urinary tract infections and diarrhea. Current identification strategies for these three species vary in complexity and typically rely on the use of multiple phenotypic and genetic tests. To facilitate their rapid identification, we developed a multiplex PCR assay targeting conserved, species-specific genes. We used the Daydreamer™ (Pattern Genomics, USA) software platform to concurrently analyze whole genome sequence assemblies (WGS) from 150 Enterobacteriaceae genomes (107 E. coli, 5 Shigella spp., 21 E. albertii, 12 E. fergusonii and 5 other species) and design primers for the following species-specific regions: a 212bp region of the cyclic di-GMP regulator gene (cdgR, AW869_22935 from genome K-12 MG1655, CP014225) for E. coli/Shigella; a 393bp region of the DNA-binding transcriptional activator of cysteine biosynthesis gene (EAKF1_ch4033 from genome KF1, CP007025) for E. albertii; and a 575bp region of the palmitoleoyl-acyl carrier protein (ACP)-dependent acyltransferase (EFER_0790 from genome ATCC 35469, CU928158) for E. fergusonii. We incorporated the species-specific primers into a conventional multiplex PCR assay and assessed its performance with a collection of 97 Enterobacteriaceae strains. The assay was 100% sensitive and specific for detecting the expected species and offers a quick and accurate strategy for identifying E. coli, E. albertii, and E. fergusonii in either a single reaction or by in silico PCR with sequence assemblies. Published by Elsevier B.V.

Mutants of Escherichia coli K-12 with enhanced resistance to ionizing radiation

International Nuclear Information System (INIS)

Verbenko, V.N.; Akhmedov, A.T.; Kalinin, V.L.

1986-01-01

By means of one-dimensional electrophoresis, it is shown that in radiation-resistant Gam 444 ad Gam 445 mutants of Escherichia coli K-12 high-molecular weight heat shock proteins are hyperproduced at 32-37 deg C and are induced more intensively during heat shock (in comparison to the parental) wild-tupe strain AB parallel 57). When the missense htp R15 mutation of the positive regulatory htpR gene for heat shock proteins was introduced by transduction into genome of the Gam 444 mutant, its enhanced radiation-resistance disappeared but could not be restored upon introduction of pKV3 plasmid bearing the htpR, gene. These data show that heat shock Protens are participating in the enhanced radioresistance of Gam mutants

Synergistic effects in mixed Escherichia coli biofilms

DEFF Research Database (Denmark)

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

2006-01-01

Bacterial biofilms, often composed of multiple species and genetically distinct strains, develop under complex influences of cell-cell interactions. Although detailed knowledge about the mechanisms underlying formation of single-species laboratory biofilms has emerged, little is known about...... the pathways governing development of more complex heterogeneous communities. In this study, we established a laboratory model where biofilm-stimulating effects due to interactions between genetically diverse strains of Escherichia coli were monitored. Synergistic induction of biofilm formation resulting from...... the cocultivation of 403 undomesticated E. coli strains with a characterized E. coli K-12 strain was detected at a significant frequency. The survey suggests that different mechanisms underlie the observed stimulation, yet synergistic development of biofilm within the subset of E. coli isolates (n = 56) exhibiting...

Determination of gamma radiation dose to the destruction of Escherichia coli O157: H7 in hamburger

International Nuclear Information System (INIS)

Orejuela Chirinos, Rodolfo Raul

1999-01-01

Escherichia coli O157:H7 has been incriminated in several foodborne outbreaks due to the consumption of different kinds of foods. Among these, hamburgers are the most common. Irradiation process is an effective method for food preservation because it causes no significant change in organoleptic and nutritional food characteristics and destroys pathogens and spoilage microorganisms. Hamburgers and nutrient broth inoculated with Escherichia coli O157:H7 were submitted to gamma irradiation ( 60 Co) treatment, with doses ranging from 0,0 to 0,7 kGy in order to calculate the D 10 for this bacteria in these substrate. The D 10 for the pathogen nutrient broth ranged from 0.08 kGy to 0.10 kGy and in hamburger from 0.11 kGy to 0.21 kGy. Considering the highest D 10 value in hamburger, a dose of 0,8 kGy would not change the sensorial characteristics of the product, and would reduce the population of E. coli O157:H7 in 4 cycles logarithmic. (author)

Environmental and genetic factors affecting mutability to aminoglycoside antibiotics among Escherichia coli K12 strains

Directory of Open Access Journals (Sweden)

Monteiro A.C.M.

2003-01-01

Full Text Available Environmental and genetic factors affecting the in vitro spontaneous mutation frequencies to aminoglycoside resistance in Escherichia coli K12 were investigated. Spontaneous mutation frequencies to kanamycin resistance were at least 100 fold higher on modified Luria agar (L2 plates, when compared to results obtained in experiments carried out with Nutrient agar (NA plates. In contrast to rifampincin, the increased mutability to kanamycin resistance could not be attributed to a mutator phenotype expressed by DNA repair defective strains. Kanamycin mutant selection windows and mutant preventive concentrations on L2 plates were at least fourfold higher than on NA plates, further demonstrating the role of growth medium composition on the mutability to aminoglycosides. Mutability to kanamycin resistance was increased following addition of sorbitol, suggesting that osmolarity is involved on the spontaneous mutability of E. coli K12 strains to aminoglycosides. The spontaneous mutation rates to kanamycin resistance on both L2 and NA plates were strictly associated with the selective antibiotic concentrations. Moreover, mutants selected at different antibiotic concentrations expressed heterogeneous resistance levels to kanamycin and most of them expressing multiple resistance to all tested aminoglycoside antibiotics (gentamicin, neomycin, amykacin and tobramycin. These results will contribute to a better understanding of the complex nature of aminoglycoside resistance and the emergence of spontaneous resistant mutants among E. coli K12 strains.

Deficiency in L-serine deaminase interferes with one-carbon metabolism and cell wall synthesis in Escherichia coli K-12.

Science.gov (United States)

Zhang, Xiao; El-Hajj, Ziad W; Newman, Elaine

2010-10-01

Escherichia coli K-12 provided with glucose and a mixture of amino acids depletes L-serine more quickly than any other amino acid even in the presence of ammonium sulfate. A mutant without three 4Fe4S L-serine deaminases (SdaA, SdaB, and TdcG) of E. coli K-12 is unable to do this. The high level of L-serine that accumulates when such a mutant is exposed to amino acid mixtures starves the cells for C(1) units and interferes with cell wall synthesis. We suggest that at high concentrations, L-serine decreases synthesis of UDP-N-acetylmuramate-L-alanine by the murC-encoded ligase, weakening the cell wall and producing misshapen cells and lysis. The inhibition by high L-serine is overcome in several ways: by a large concentration of L-alanine, by overproducing MurC together with a low concentration of L-alanine, and by overproducing FtsW, thus promoting septal assembly and also by overexpression of the glycine cleavage operon. S-Adenosylmethionine reduces lysis and allows an extensive increase in biomass without improving cell division. This suggests that E. coli has a metabolic trigger for cell division. Without that reaction, if no other inhibition occurs, other metabolic functions can continue and cells can elongate and replicate their DNA, reaching at least 180 times their usual length, but cannot divide.

PATHOGENIC POTENTIALS OF ESCHERICHIA COLI ISOLATED ...

African Journals Online (AJOL)

Electrolyte and haematological parameters in rabbits infected with pathogenic isolates of Escherichia coli from rural water supplies in Rivers State, Nigeria, where monitored. Rabbits were orally infected with suspension containing 3x107 cfu /ml of Escherichia coli to induce diarrhoea, and the electrolyte (sodium, potassium ...

77 FR 9888 - Shiga Toxin-Producing Escherichia coli

Science.gov (United States)

2012-02-21

... Toxin-Producing Escherichia coli in Certain Raw Beef Products AGENCY: Food Safety and Inspection Service... toxin-producing Escherichia coli (STEC) serogroups (O26, O45, O103, O111, O121, and O145). This new date..., that are contaminated with Shiga toxin-producing Escherichia coli (STEC) O26, O45, O103, O111, O121...

Irradiation effect of escherichia coli O157 : H7 in meats

International Nuclear Information System (INIS)

Ito, Hitoshi; Harsojo

1998-01-01

Escherichia coli O157 : H7 is a rapidly emerging food-born pathogen which has been linked to outbreaks of hemorrhagic diarrhea in Japan, USA or many European countries. From this study, two strains of E. coli O157 : H7 were isolated from beef and chicken meats in each one sample of 4 replicates. Some of the biochemical characteristics of these isolates were different from type strain IID959. These isolates could grow quickly at 10degC on cultivation of nutrient agar. D 10 value of these isolates were obtained to be 0.06kGy in 0.067M phosphate buffer suspension which were highly sensitive than D 10 value of 0.12kGy on type strain IID959. On the irradiation effect of type strain IID959 in ground beef, D 10 value was obtained as 0.26kGy at fresh condition and 0.46kGy at frozen condition, respectively. From these results, necessary dose for elimination of E. coli O157 : H7 was decided as 1.5kGy for fresh meats and 3kGy for frozen meats. (author)

Electrochemical magneto immunosensor based on endogenous β-galactosidase enzyme to determine enterotoxicogenic Escherichia coli F4 (K88) in swine feces using square wave voltammetry.

Science.gov (United States)

Viviana Tarditto, Lorena; Alicia Zon, María; García Ovando, Hugo; Roberto Vettorazzi, Nelio; Javier Arévalo, Fernando; Fernández, Héctor

2017-11-01

Diseases caused by enterotoxicogenic Escherichia coli F4 (K88) (ETEC F4) are a problem in swine production establishments. Due to the high rate of mortality and morbidity of E. coli infections, a rapid and accurate diagnosis is important in order to choose an appropriate treatment to reduce the economic impact. Therefore, an electrochemical magneto-immunosensor (EMI) was developed to detect and quantify ETEC F4 in swine feces samples through a direct non-competitive immunoassay. ETEC F4 was selectively captured by immunomagnetic separation. The detection principle was based on the activity of β-galactosidase endogenous enzyme (β-gal), which hydrolyses the p-aminophenyl-β-D-galactopyranoside (p-APG) producing p-aminophenol (p-AP), which was oxidized on a carbon screen printed electrode (CSPE) using square wave voltammetry (SWV). All parameters related to construction and electrochemical responses were optimized. The total analysis time to quantify ETEC F4 using the EMI was less than 2h and the limit of detection (LOD) was 33CFUmL -1 . The perceptual relative error (%E r ) was 20%. The magneto-immunosensor was validated versus conventional method of culture and plate count, obtaining a very good agreement. The EMI is simple, fast and economical to detect and quantify ETEC F4 in swine feces samples, being thus a valuable tool in swine production. Copyright © 2017 Elsevier B.V. All rights reserved.

Ultraviolet radiation-induced mutability of isogenic uvrA and uvrB strains of Escherichia coli K-12 W3110

Energy Technology Data Exchange (ETDEWEB)

Barfknecht, T R; Smith, K C [Stanford Univ., Calif. (USA). Dept. of Radiology

1977-12-01

Escherichia coli K-12 W3110 uvrB5 strain has been shown to have a higher uv-induced reversion frequency than its wild-type parent when plotted on the basis of mutation frequency versus survival. However for the E. coli B/r WP2s uvrA strain this higher mutability has been observed only at survival levels of 80 to 100%. A study was undertaken to determine if ly to the uvrA and uvrB mutations, or to other genetic background differences. Isogenic strains of E. coli K-12 W3110 carrying uvrA6, uvrB5, uvrA6, and uvrB5, and the uvrA allele from E.coli B/r WP2s were used. Results indicate that the enrichment of minimal medium with a small amount of nutrient broth is sufficient to inhibit minimal medium recovery (MMR) and to enhance leu/sup +/ reversion of the leu B missense mutation in these uvr/sup -/ strains. This suggests that there may be a relationship between MMR and error-free postreplication repair. Further research is in progress to clarify the relationship between MMR and broth enhancement of uv-induced mutagenesis in uvr/sup -/ strains of E. Coli K-12 W3110.

FimH adhesin of Escherichia coli K1 type 1 fimbriae activates BV-2 microglia

International Nuclear Information System (INIS)

Lee, Jongseok; Shin, Sooan; Teng, C.-H.; Hong, Suk Jin; Kim, Kwang Sik

2005-01-01

The generation of intense inflammation in the subarachnoid space in response to meningitis-causing bacteria contributes to brain dysfunction and neuronal injury in bacterial meningitis. Microglia, the major immune effector cells in the central nervous system (CNS), become activated by bacterial components to produce proinflammatory immune mediators. In this study, we showed that FimH adhesin, a tip component of type 1 fimbriae of meningitis-causing Escherichia coli K1, activated the murine microglial cell line, BV-2, which resulted in the production of nitric oxide and the release of tumor necrosis factor-α. Mitogen-activated protein kinases, ERK and p-38, and nuclear factor-κB were involved in FimH adhesin-mediated microglial activation. These findings suggest that FimH adhesin contributes to the CNS inflammatory response by virtue of activating microglia in E. coli meningitis

Induction of the lambda bacteriophage synthesis in Escherichia coli K 12 by polonium alpha rays; Induction de la synthese du bacteriophage lambda chez Escherichia coli K 12 par les rayons alpha du polonium

Energy Technology Data Exchange (ETDEWEB)

Devoret, Raymond

1958-06-15

This research thesis reports the study of the inducing action of polonium alpha radiations in Escherichia Coli K 12 by using an external irradiation device. This work comprised the development of a method to spread bacteria in layer with a thickness less than 20 microns, and the measurement of the number of α particles falling on the irradiated surface. This measurement has been performed by using a nuclear emulsion and a simple photographic film. It appears that alpha radiations have an inducing action, and that at most 15 per cent of bacteria can be induced. The comparison of the induction curve with the survival curves of lysogen and sensitive stains shows that there is no abortive induction. Thus, it appears that this inducing action is not due to an indirect effect of the irradiated medium [French] Dans ce travail on a etudie l'action inductrice des rayons alphas du polonium chez Escherichia Coli K 12 par un diapoaitif d'irradiation externe. Son utilisation necessitait: - une methode d'etalement des bacteries en couche de moins de 20 microns d'epaisseur; - une mesure du nombre des particules alpha tombant sur la surface etendue irradiee. Les mesures ont ete faites a l'aide d'une emulsion nucleaire et d'un film photographique ordinaire. 1) Les rayons alphas ont une action inductrice. Au plus 15 pc des bacteries peuvent etre induites. 2) La oomparaison de la courbe d'induction et des courbes de survie des souches lysogene et sensible montre qu'il n'y a pas d'inductions abortives. 3) Cette action inductrice n'est pas due a un effet indirect du milieu irradie. (auteur)

Effects of casein glycomacropeptide supplementation on growth performance, intestinal morphology, intestinal barrier permeability and inflammatory responses in Escherichia coli K88 challenged piglets

Directory of Open Access Journals (Sweden)

Yili Rong

2015-06-01

Full Text Available Casein glycomacropeptide (CGMP is a bioactive peptide derived from milk with multiple functions. This study was aimed at evaluating the effects of CGMP as a potential feed additive on growth performance, intestinal morphology, intestinal barrier permeability and inflammatory responses of Escherichia coli K88 (E. coli K88 challenged piglets. Eighteen weaning piglets were randomly assigned to three groups. Control group and K88 challenged group received a basal diet, and CGMP treated group received the basal diet supplemented with 1% of CGMP powder. The trail lasted for 12 days, K88 was orally administered to the piglets of K88 challenged group and CGMP treated group on days 8–10. The results showed that the diet containing 1% CGMP significantly alleviated the decrease in average daily gain (P  0.05 and barrier permeability damage (P < 0.05, and acute inflammatory response (P < 0.05 induced by E. coli K88 infection. In conclusion, CGMP supplementation in the diet protected the weaning piglets against E. coli K88 infection.

Deficiency in l-Serine Deaminase Interferes with One-Carbon Metabolism and Cell Wall Synthesis in Escherichia coli K-12▿

Science.gov (United States)

Zhang, Xiao; El-Hajj, Ziad W.; Newman, Elaine

2010-01-01

Escherichia coli K-12 provided with glucose and a mixture of amino acids depletes l-serine more quickly than any other amino acid even in the presence of ammonium sulfate. A mutant without three 4Fe4S l-serine deaminases (SdaA, SdaB, and TdcG) of E. coli K-12 is unable to do this. The high level of l-serine that accumulates when such a mutant is exposed to amino acid mixtures starves the cells for C1 units and interferes with cell wall synthesis. We suggest that at high concentrations, l-serine decreases synthesis of UDP-N-acetylmuramate-l-alanine by the murC-encoded ligase, weakening the cell wall and producing misshapen cells and lysis. The inhibition by high l-serine is overcome in several ways: by a large concentration of l-alanine, by overproducing MurC together with a low concentration of l-alanine, and by overproducing FtsW, thus promoting septal assembly and also by overexpression of the glycine cleavage operon. S-Adenosylmethionine reduces lysis and allows an extensive increase in biomass without improving cell division. This suggests that E. coli has a metabolic trigger for cell division. Without that reaction, if no other inhibition occurs, other metabolic functions can continue and cells can elongate and replicate their DNA, reaching at least 180 times their usual length, but cannot divide. PMID:20729359

Transcriptome of E. coli K1 bound to human brain microvascular endothelial cells

OpenAIRE

Xie, Yi; Parthasarathy, Geetha; Di Cello, Francescopaolo; Teng, Ching-Hao; Paul-Satyaseela, Maneesh; Kim, Kwang Sik

2007-01-01

Escherichia coli K1 is the most common Gram-negative organism causing neonatal meningitis. Binding to human brain microvascdular endothelial cells (HBMEC) is an essential step for E. coli K1 traversal of the blood-brain barrier. In this study, we examined expression profiles of E. coli K1 strain RS218 during its binding to HBMEC. Comparison of HBMEC-bound E. coli K1 with collagen-bound E. coli revealed more than one hundred genes whose expression patterns were significantly changed in HBMEC-b...

YibK is the 2'-O-methyltransferase TrmL that modifies the wobble nucleotide in Escherichia coli tRNA(Leu) isoacceptors

DEFF Research Database (Denmark)

Benítez-Páez, Alfonso; Villarroya, Magda; Douthwaite, Stephen Roger

2010-01-01

to uncover candidate E. coli genes for the missing enzyme(s). Transfer RNAs from null mutants for candidate genes were analyzed by mass spectrometry and revealed that inactivation of yibK leads to loss of 2'-O-methylation at position 34 in both tRNA(Leu)(CmAA) and tRNA(Leu)(cmnm5UmAA). Loss of Yib...... of the wobble nucleotide; YibK recognition of this target requires a pyridine at position 34 and N⁶-(isopentenyl)-2-methylthioadenosine at position 37. YibK is one of the last remaining E. coli tRNA modification enzymes to be identified and is now renamed TrmL.......Transfer RNAs are the most densely modified nucleic acid molecules in living cells. In Escherichia coli, more than 30 nucleoside modifications have been characterized, ranging from methylations and pseudouridylations to more complex additions that require multiple enzymatic steps. Most...

Development of an Escherichia coli K12-specific quantitative polymerase chain reaction assay and DNA isolation suited to biofilms associated with iron drinking water pipe corrosion products

Science.gov (United States)

Escherichia coli is one of the most commonly used fecal indicator organisms for drinking water and groundwater systems. In order to understand various biogeochemical and biophysical factors affecting its interactions with biofilms, E. coli K12 was chosen as a model organism. A Ta...

Escherichia Coli

Science.gov (United States)

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…

Transport proteins promoting Escherichia coli pathogenesis

Science.gov (United States)

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

Transport proteins promoting Escherichia coli pathogenesis.

Science.gov (United States)

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. Copyright © 2014 Elsevier Ltd. All rights reserved.

Genetic Control of the Secondary Modification of Deoxyribonucleic Acid in Escherichia coli1

Science.gov (United States)

Mamelak, Linda; Boyer, Herbert W.

1970-01-01

The wild-type restriction and modification alleles of Escherichia coli K-12 and B were found to have no measurable effect on the patterns of methylated bases in the deoxyribonucleic acid (DNA) of these strains. The genetic region controlling the methylation of cytosine in E. coli K-12 was mapped close to his, and the presence or absence of this gene in E. coli B or E. coli K had no effect on the restriction and modification properties of these strains. Thus, only a few of the methylated bases in the DNA of these strains are involved in host modification, and the biological role of the remainder remains obscure. PMID:4919756

Identification of substrate repertoire of rhomboid intramembrane protease GlpG from Escherichia coli

Czech Academy of Sciences Publication Activity Database

Began, Jakub; Březinová, Jana; Škerle, Jan; Stříšovský, Kvido

2017-01-01

Roč. 15, č. 1 (2017), s. 4-5 ISSN 2336-7202. [Mezioborové setkání mladých biologů, biochemiků a chemiků /17./. 30.05.2017-01.06.2017, Milovy] R&D Projects: GA MŠk(CZ) LK11206 Institutional support: RVO:61388963 Keywords : intramembrane protease * Escherichia coli * GlpG Subject RIV: CE - Biochemistry

Control of utilization of L-arginine, L-ornithine, agmatine, and putrescine as nitrogen sources in Escherichia coli K-12.

OpenAIRE

Shaibe, E; Metzer, E; Halpern, Y S

1985-01-01

The regulation of the synthesis of the enzymes involved in the utilization of L-arginine, L-ornithine, agmatine, and putrescine as a sole nitrogen source in Escherichia coli K-12 was examined. The synthesis of agmatine ureohydrolase, putrescine aminotransferase, and pyrroline dehydrogenase is dually controlled by catabolite repression and nitrogen availability. Catabolite repression of agmatine ureohydrolase, but not that of putrescine aminotransferase or pyrroline dehydrogenase, is relieved ...

Inactivation of Escherichia coli inoculated onto fresh-cut chopped cabbage using electron-beam processing.

Science.gov (United States)

Grasso, Elizabeth M; Uribe-Rendon, Roberto M; Lee, Ken

2011-01-01

During the past decade there were more than 50 reported outbreaks involving leafy green vegetables contaminated with foodborne pathogens. Leafy greens, including cabbage, are fresh foods rarely heated before consumption, which enables foodborne illness. The need for improved safety of fresh food drives the demand for nonthermal food processes to decrease the risk of pathogens while maintaining fresh quality. This study examines the efficacy of electron-beam (e-beam) irradiation in decreasing indigenous microflora on fresh-cut cabbage and determines the optimal dosage to pasteurize fresh-cut cabbage inoculated with Escherichia coli K-12. Fresh-cut cabbage (100 g) was inoculated with ∼8 log E. coli K-12 and e-beam irradiated at doses of 0, 1.0, 2.3, or 4.0 kGy. At 2.3 kGy there was 7-log reduction of E. coli K-12 in the fresh-cut cabbage. The D(10)-value for E. coli K-12 in fresh-cut cabbage was 0.564 kGy. E-beam irradiation is thus a viable nonthermal treatment that extends the shelf life and increases the safety of fresh cabbage by reducing or eliminating indigenous microflora and unwanted pathogens.

beta-Chloro-L-alanine inhibition of the Escherichia coli alanine-valine transaminase.

OpenAIRE

Whalen, W A; Wang, M D; Berg, C M

1985-01-01

beta-Chloro-L-alanine, an amino acid analog which inhibits a number of enzymes, reversibly inhibited the Escherichia coli K-12 alanine-valine transaminase, transaminase C. This inhibition, along with the inhibition of transaminase B, accounted for the isoleucine-plus-valine requirement of E. coli in the presence of beta-chloro-L-alanine.

Attachment behaviour of Escherichia coli K12 and Salmonella Typhimurium P6on food contact surfaces for food transportation

DEFF Research Database (Denmark)

Abban, Stephen; Jakobsen, Mogens; Jespersen, Lene

2012-01-01

The role of cargo container lining materials aluminium, a fibre reinforced plastic (FRP) and stainless steel in bacterial cross contamination during transport was assessed. For this, attachment and detachment of Escherichia coli K12 and Salmonella Typhimurium P6 on the three surfaces in the absence....... Typhimurium P6 respectively. Correlation with roughness average was poor; r = -0.425 and -0.413 respectively for E. coli K12 and S. Typhimurium P6. Presence of residue caused significant reduction (p ... material sections of the same surfaces. We report these observations for the first time for aluminium and the FRP material and in part for stainless steel. The S. Typhimurium P6 strain also had significantly higher level of attachment than the E. coli K12 strain. Our findings show that food residue...

Gene encoding virulence markers among Escherichia coli isolates ...

African Journals Online (AJOL)

River water sources and diarrhoeic stools of residents in the Venda Region, Limpopo Province of South Africa were analysed for the prevalence of Escherichia coli (E. coli) and the presence of virulence genes among the isolates. A control group of 100 nondiarrhoeic stool samples was included. Escherichia coli was ...

Antibiotic resistance of Verotoxigenic Escherichia coli isolated from vegetables

Directory of Open Access Journals (Sweden)

mojtaba boniadian

2017-01-01

Full Text Available Introduction: Human gastrointestinal disease caused by verotoxigenic Escherichia coli has been diagnosed for recent decades. Escherichia coli O157:H7 is the most important serotype of verotoxigenic Escherichia coli that cause hemolytic uremic syndrome and hemorrhagic colitis in humans. This study was conducted to determine the occurrence of verotoxigenic E. coli and antibiotic resistance of the isolates from vegetables. Materials and methods: A total of 500 fresh vegetable samples were collected randomly from retail shops in Shahrekord, Iran. E. coli was isolated and identified using bacteriological and biochemical tests. PCR method was used to identify the rbfE, stx1, stx2 and eae genes. Also, antibiotic resistance of the isolates was determined by disk diffusion method. Results: The results represented that among 25 isolates possess virulence genes, 40, 12 and 4% of the isolates contained eaeA, STx2, and both genes, respectively. But none of them contained H7, STx1, and rfbE genes. The antibiotic resistance pattern demonstrated that the isolates were highly resistant to Gentamycin and cefotoxime. Discussion and conclusion: The results of this study showed that the presence of verotoxigenic E.coli in vegetables; and high resistance of the isolates to antibiotics could be hazardous for public health.

escherichia coli serotypes confirmed in experimental mammary ...

African Journals Online (AJOL)

DJFLEX

VARIATIONS IN VIRULENCE OF THREE (3) ESCHERICHIA COLI. SEROTYPES CONFIRMED IN ... ows are susceptible to E. coli infection because. E. coli exist in the .... Coli infections in mice: A laboratory animal model for research in.

Elimination of Escherichia coli O157:H7 in meats by gamma irradiation

International Nuclear Information System (INIS)

Thayer, D.W.; Boyd, G.

1993-01-01

Undercooked and raw meat has been linked to outbreaks of hemorrhagic diarrhea due to the presence of Escherichia coli O157:H7; therefore, treatment with ionizing radiation was investigated as a potential method for the elimination of this organism. Response-surface methods were used to study the effects of irradiation dose (0 to 2.0 kGy), temperature (-20 to +20 degrees C), and atmosphere (air and vacuum) on E. coli O157:H7 in mechanically deboned chicken meat. Differences in irradiation dose and temperature significantly affected the results. Ninety percent of the viable E. coli in chicken meat was eliminated by doses of 0.27 kGy at +5 degrees C and 0.42 kGy at -5 degrees C. Small, but significant, differences in radiation resistance by E. coli were found when finely ground lean beef rather than chicken was the substrate. Unlike nonirradiated samples, no measurable verotoxin was found in finely ground lean beef which had been inoculated with 10(4.8) CFU of E. coli O157:H7 per g, irradiated at a minimum dose of 1.5 kGy, and temperature abused at 35 degrees C for 20 h. Irradiation is an effective method to control this food-borne pathogen

Competitive accumulation of betaines by Escherichia coli K-12 and derivative strains lacking betaine porters.

Science.gov (United States)

Randall, K; Lever, M; Peddie, B A; Chambers, S T

1995-08-17

Escherichia coli was grown in hyperosmotic media containing both glycine betaine and one other betaine. E. coli K-12 derivative WG439 (putP- proP- proU-) did not accumulate any of 15 betaines. Strains WG445 (putP- proP- proU+), WG443 (putP- proP+ proU-) and the control strains all accumulated less betaine, (CH3)3N(+)-(CH2)n-COO-, when n was greater than 1. Accumulation was not detectable when n = 5. Both L- and D-isomers of alpha-substituted betaines were accumulated by both strains WG443 and WG445, the D-isomers more slowly. Hydroxylated alpha-substituted betaines were accumulated relatively more through the osmoregulated transport protein ProU than through ProP. In actively growing cultures glycine betaine appeared to be the preferred substrate for accumulation, but the proportion of the second accumulated betaine increased as cultures approached stationary phase.

UV irradiation alters deoxynucleoside triphosphate pools in Escherichia coli

International Nuclear Information System (INIS)

Das, S.K.; Loeb, L.A.

1984-01-01

UV irradiation of exponentially growing Escherichia coli increased intracellular concentration of dATP and dTTP without significantly changing the concentrations of dGTP and dCTP. These selective increases in dATP and dTTP pools are seen in wild-type E. coli K12 and AB1157, as well as in recA and umuC strains, and are proportional to UV dose. The possible significance of these findings with respect to induction of the SOS response and nontargeted mutagenesis are discussed. (orig.)

Heterologous expression of mannanase and developing a new Reporter gene system in Lactobacillus casei and Escherichia coli

DEFF Research Database (Denmark)

Lin, Jinzhong; Zou, Yexia; Ma, Chengjie

2015-01-01

Reporter gene systems are useful for studying bacterial molecular biology, including the regulation of gene expression and the histochemical analysis of protein products. Here, two genes, β-1,4-mannanase (manB) from Bacillus pumilus and β-glucuronidase (gusA) from Escherichia coli K12, were clone....... casei and E.coli....

Bacteraemia Caused by Escherichia Coli in Cancer Patients at a Specialist Center in Pakistan

International Nuclear Information System (INIS)

Parveen, A.; Sultan, F.; Saleem, S.; Nazeer, S. H.; Raza, A.; Zafar, W.; Nizamuddin, S.; Mahboob, A.

2015-01-01

Objective: To analyse the antimicrobial susceptibility patterns of Escherichia coli bacteraemia among cancer patients, and to assess the risk factors and outcomes of multidrug-resistant Escherichia coli bacteraemia. Methods: The retrospective study was conducted at Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore, and comprised medical records of patients with Escherichia coli bacteraemia presenting between December 2012 and November 2013. Multivariable logistic regression analyses were used to determine the factors associated with the development and 30-day mortality of multidrug-resistant Escherichia coli bacteraemia. Results: Out of 1603 episodes of bacteraemia, 227(35.6 percent) were caused by E.coli, of which 98(43.2 percent) were multidrug-resistant. In multivariable analysis, age less than 18 years (adjusted odds ratio 3.92; 95 percent confidence interval 1.43-10.68), presence of central venous catheter (adjusted odds ratio 2.12; 95 percent confidence interval 1.04-4.33) and exposure to piperacillin/tazobactam within 90 days prior to infection (adjusted odds ratio 2.37; 95 percent confidence interval 1.15-4.86) were identified as independent risk factors for acquisition of multidrug-resistant Escherichia coli bacteraemia. The overall 30 day mortality rate was 35.2 percent (80/227). Risk factors for mortality were intensive care unit admission (adjusted odds ratio 3.95; 95 percent confidence interval 1.79-8.71) and profound neutropenia (adjusted odds ratio 4.03; 95 percent confidence interval 1.55-10.49). Conclusion: Bloodstream infections with multidrug-resistant Escherichia coli were common in cancer patients. However it was not a predictor of mortality. (author)

Chromatin architecture and gene expression in Escherichia coli

DEFF Research Database (Denmark)

Willenbrock, Hanni; Ussery, David

2004-01-01

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

Escherichia coli O104 associated with human diarrhea, South Africa, 2004-2011.

Science.gov (United States)

Tau, Nomsa P; Meidany, Parastu; Smith, Anthony M; Sooka, Arvinda; Keddy, Karen H

2012-08-01

To determine the origin of >4,000 suspected diarrheagenic Escherichia coli strains isolated during 2004-2011 in South Africa, we identified 7 isolates as serotype O104; 5 as enteroaggregative E. coli O104:H4, and 2 as enteropathogenic E. coli O104:non-H4. Pulsed-field gel electrophoresis showed that these isolates were unrelated to the 2011 E. coli O104:H4 outbreak strain from Germany.

DnaB gene product-independence of DNA polymerase III-directed repair synthesis in Escherichia coli K-12

International Nuclear Information System (INIS)

Billen, D.; Hellermann, G.R.

1977-01-01

An investigation has been carried out into the role of dnaB gene product in X-ray-induced repair synthesis carried out by DNA polymerase III in toluene-treated Escherichia coli K-12. A polAl polBlOO dnaB mutant deficient in both DNA polymerase I and II activities was used, and it was shown that the level of X-ray-induced, ATP-dependent, non-conservative DNA synthesis was, unlike semi-conservative DNA synthesis, unaffected by a temperature shift from 30 0 to 42 0 C. The dnaB gene product was not therefore necessary for DNA polymerase III-directed repair synthesis, which occurred in the absence of replicative synthesis. (U.K.)

Agentes bacterianos enteropatogênicos em suínos de diferentes faixas etárias e perfil de resistência a antimicrobianos de cepas de Escherichia coli e Salmonella spp Enteropathogenic bacterial agents in pigs of different age groups and profile of resistance in strains of Escherichia coli and Salmonella spp. to antimicrobial agents

Directory of Open Access Journals (Sweden)

Álvaro Menin

2008-09-01

Full Text Available As enterites infecciosas bacterianas provocam severas perdas para a indústria suína em todo o mundo. Os objetivos deste trabalho foram determinar os agentes bacterianos, associados com a ocorrência de diarréia em suínos, em diferentes faixas etárias, no Estado de Santa Catarina, Brasil, e verificar o perfil de resistência das cepas de Escherichia coli e Salmonella spp, frente aos principais antimicrobianos utilizados em granjas de suínos. Os principais gêneros/espécies bacterianos diagnosticados foram Escherichia coli, Clostridium spp, Salmonella spp Brachyspira hyodysenteriae, Brachyspira pilosicoli e Lawsonia intracellularis. Os fatores de virulência de E. coli mais prevalentes na fase de maternidade foram F5 / (K99 20%, F6 / (987P 16,3%, F42 6,8% e F41 5,7%, já nas fases de creche e terminação, predominaram cepas com fimbrias F4 (K88 11,2% e 5,4%, respectivamente. Para E. coli os maiores índices de resistência foram encontrados para oxitetraciclina (94% e tetraciclina (89,5% e os menores índices de resistência para neomicina (55%, ceftiofur (57,4%. Quanto às amostras de Salmonella spp, estas apresentaram maior resistência à oxitetraciclina (77%, e à tetraciclina (42,1% e menor à gentamicina (3,5% e amoxicilina (4,8%.Infectious bacterial enteritis causes severe losses to the swine industry worldwide. The objective of this study was to determine the epidemiology of bacterial agents that are associated with the occurrence of diarrhea in pigs at different age groups, and to verify the profile of resistance of strains of Escherichia coli and Salmonella spp to the main antimicrobial agents. The main bacterial species diagnosed were Escherichia coli, Clostridium spp, Salmonella spp, Brachyspira hyodysenteriae, Brachyspira pilosicoli and Lawsonia intracellularis. The E. coli virulence factors of higher prevalence in preweaning piglets were F5 / (K99 20%, F6 / (987P 16.3%, F42 6.8% and F41 5.7%, whereas at the nursery and with

Type 1 fimbrial expression enhances Escherichia coli virulence for the urinary tract

DEFF Research Database (Denmark)

Connell, Hugh; Agace, William; Klemm, Per

1996-01-01

of Escherichia coli for the urinary tract by promoting bacterial persistence and enhancing the inflammatory responce to infection. In a clinical study, we observed that disease severity was greater in children infected with E. coli O1:K1:H7 isolates expressing type 1 fimbriae than in those infected with type 1...... negative isolates of the same serotype. The E. coli O1:K1:H7 isolates had the same electrophoretic type, were hemolysin-negative, expressed P fimbriae, and carried the fim DNA sequences. When tested in a mouse urinary tract infection model, the type 1-positive E. coli O1:K1:H7 isolates survived inhigher...... urinary tract infection model. E. coli CN1016 reconstituted with type 1 fimbriae had restored virulence similar to that of the wild-type parent strain. These results show that type 1 fimbriae in the genetic background of a uropathogenic strain contribute to the pathogenesis of E. coli in the urinary tract....

Effect of chicken egg anti-F4 antibodies on performance and diarrhea incidences in enterotoxigenic Escherichia coli K88+-challenged piglets.

Science.gov (United States)

Aluko, Kolawole; Velayudhan, Deepak E; Khafipour, Ehsan; Fang, Lin; Nyachoti, Martin

2017-12-01

The aim was to evaluate the effects of dietary supplementation of spay-dried whole egg containing anti-F4 antibodies (SDWE) against recombinantly produced F4 antigens in enterotoxigenic Escherichia coli K88 + (ETEC)-challenged piglets. Twenty-seven 21-d-old and individually housed piglets were randomly allotted to 3 treatments consisting of a wheat-soybean meal basal diet containing either 0 (control egg powder; CEP), 0.1% (SDWE1) or 0.4% (SDWE2) SDWE. After a 7-d adaptation period, blood samples were collected from all pigs, and pigs were weighed and orally challenged with an ETEC inoculum. Blood was sampled at 24 and 48 h post-challenge, and diarrhea incidences and scores were recorded. On d 14, all pigs were weighed and then euthanized to obtain intestinal tissue samples for histomorphology measurement. During the pre-challenge period, pigs fed the SDWE showed a linear improvement ( P  < 0.05) in average daily gain (ADG) and gain to feed ratio (G:F), but there were no differences among treatments in growth performance during the post-challenge period. Diarrhea incidences and scores, fecal shedding of ETEC, plasma urea nitrogen content and intestinal histomorphology were similar among treatments. The results show that 0.4% SDWE supported greater piglet performance before challenge although such benefits were not evident during the post-challenge period at either 0.1% or 0.4% supplementation.

DNA microarray analysis of fim mutations in Escherichia coli

DEFF Research Database (Denmark)

Schembri, Mark; Ussery, David; Workman, Christopher

2002-01-01

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

Simulation of the rate of transfer of antibiotic resistance between Escherichia coli strains cultured under well controlled environmental conditions

NARCIS (Netherlands)

Smelt, J.P.; Hoefsloot, H.C.; de Koster, C.G.; Schuurmans, J.M.; ter Kuile, B.H.; Brul, S.

2015-01-01

It was demonstrated that the tetracycline resistance plasmid in Escherichia coli resembling K-12 23:06 containing the E. coli plasmid DM0133 could be transferred to tetracycline sensitive E. coli K-12 MG1655 YFP. The sensitive recipient strain has a slight metabolic advantage in continuous

Administration of probiotics influences F4 (K88-positive enterotoxigenic Escherichia coli attachment and intestinal cytokine expression in weaned pigs

Directory of Open Access Journals (Sweden)

Daudelin Jean-François

2011-05-01

Full Text Available Abstract This study evaluated the effect of the probiotics Pediococcus acidilactici and Saccharomyces cerevisiae boulardii on the intestinal colonization of O149 enterotoxigenic Escherichia coli harbouring the F4 (K88 fimbriae (ETEC F4 and on the expression of ileal cytokines in weaned pigs. At birth, different litters of pigs were randomly assigned to one of the following treatments: 1 control without antibiotics or probiotics (CTRL; 2 reference group in which chlortetracycline and tiamulin were added to weanling feed (ATB; 3 P. acidilactici; 4 S. cerevisiae boulardii; or 5 P. acidilactici + S. cerevisiae boulardii. Probiotics were administered daily (1 × 109 CFU per pig during the lactation period and after weaning (day 21. At 28 days of age, all pigs were orally challenged with an ETEC F4 strain, and a necropsy was performed 24 h later. Intestinal segments were collected to evaluate bacterial colonization in the small intestine and ileal cytokine expressions. Attachment of ETEC F4 to the intestinal mucosa was significantly reduced in pigs treated with P. acidilactici or S. cerevisiae boulardii in comparison with the ATB group (P = 0.01 and P = 0.03, respectively. In addition, proinflammatory cytokines, such as IL-6, were upregulated in ETEC F4 challenged pigs treated with P. acidilactici alone or in combination with S. cerevisiae boulardii compared with the CTRL group. In conclusion, the administration of P. acidilactici or S. cerevisiae boulardii was effective in reducing ETEC F4 attachment to the ileal mucosa, whereas the presence of P. acidilactici was required to modulate the expression of intestinal inflammatory cytokines in pigs challenged with ETEC F4.

Administration of probiotics influences F4 (K88)-positive enterotoxigenic Escherichia coli attachment and intestinal cytokine expression in weaned pigs.

Science.gov (United States)

Daudelin, Jean-François; Lessard, Martin; Beaudoin, Frédéric; Nadeau, Eric; Bissonnette, Nathalie; Boutin, Yvan; Brousseau, Jean-Philippe; Lauzon, Karoline; Fairbrother, John Morris

2011-05-23

This study evaluated the effect of the probiotics Pediococcus acidilactici and Saccharomyces cerevisiae boulardii on the intestinal colonization of O149 enterotoxigenic Escherichia coli harbouring the F4 (K88) fimbriae (ETEC F4) and on the expression of ileal cytokines in weaned pigs. At birth, different litters of pigs were randomly assigned to one of the following treatments: 1) control without antibiotics or probiotics (CTRL); 2) reference group in which chlortetracycline and tiamulin were added to weanling feed (ATB); 3) P. acidilactici; 4) S. cerevisiae boulardii; or 5) P. acidilactici + S. cerevisiae boulardii. Probiotics were administered daily (1 × 10(9) CFU per pig) during the lactation period and after weaning (day 21). At 28 days of age, all pigs were orally challenged with an ETEC F4 strain, and a necropsy was performed 24 h later. Intestinal segments were collected to evaluate bacterial colonization in the small intestine and ileal cytokine expressions. Attachment of ETEC F4 to the intestinal mucosa was significantly reduced in pigs treated with P. acidilactici or S. cerevisiae boulardii in comparison with the ATB group (P = 0.01 and P = 0.03, respectively). In addition, proinflammatory cytokines, such as IL-6, were upregulated in ETEC F4 challenged pigs treated with P. acidilactici alone or in combination with S. cerevisiae boulardii compared with the CTRL group. In conclusion, the administration of P. acidilactici or S. cerevisiae boulardii was effective in reducing ETEC F4 attachment to the ileal mucosa, whereas the presence of P. acidilactici was required to modulate the expression of intestinal inflammatory cytokines in pigs challenged with ETEC F4.

Genes and proteins of Escherichia coli K-12 (GenProtEC).

Science.gov (United States)

Riley, M

1997-01-01

GenProtEC is a database of Escherichia coli genes and their gene products, classified by type of function and physiological role and with citations to the literature for each. Also present are data on sequence similarities amongE.coliproteins with PAM values, percent identity of amino acids, length of alignment and percent aligned. GenProtEC can also be accessed through the World Wide Web at URL http://mbl.edu/html/ecoli.html .

Predictors Of Non-Escherichia Coli Urinary Tract Infection.

Science.gov (United States)

Shaikh, Nader; Wald, Ellen R; Keren, Ron; Gotman, Nathan; Ivanova, Anastasia; Carpenter, Myra A; Moxey-Mims, Marva; Hoberman, Alejandro

2016-11-01

We aimed to determine which children are prone to non-Escherichia coli urinary tract infection (UTIs). We included 769 children with UTI. We found that circumcised males, Hispanic children, children without fever and children with grades 3 and 4 vesicoureteral reflux were more likely to have a UTI caused by organisms other than E. coli. This information may guide clinicians in their choice of antimicrobial therapy.

Diarrheagenic Escherichia coli and acute and persistent diarrhea in returned travelers

NARCIS (Netherlands)

Schultsz, C.; van den Ende, J.; Cobelens, F.; Vervoort, T.; van Gompel, A.; Wetsteyn, J. C.; Dankert, J.

2000-01-01

To determine the role of diarrheagenic Escherichia coli in acute and persistent diarrhea in returned travelers, a case control study was performed. Enterotoxigenic E. coli (ETEC) was detected in stool samples from 18 (10.7%) of 169 patients and 4 (3.7%) of 108 controls. Enteroaggregative E. coli

Escherichia coli and Neisseria gonorrhoeae UvrD helicase unwinds G4 DNA structures.

Science.gov (United States)

Shukla, Kaustubh; Thakur, Roshan Singh; Ganguli, Debayan; Rao, Desirazu Narasimha; Nagaraju, Ganesh

2017-10-18

G-quadruplex (G4) secondary structures have been implicated in various biological processes, including gene expression, DNA replication and telomere maintenance. However, unresolved G4 structures impede replication progression which can lead to the generation of DNA double-strand breaks and genome instability. Helicases have been shown to resolve G4 structures to facilitate faithful duplication of the genome. Escherichia coli UvrD (EcUvrD) helicase plays a crucial role in nucleotide excision repair, mismatch repair and in the regulation of homologous recombination. Here, we demonstrate a novel role of E. coli and Neisseria gonorrhoeae UvrD in resolving G4 tetraplexes. EcUvrD and N gonorrhoeae UvrD were proficient in unwinding previously characterized tetramolecular G4 structures. Notably, EcUvrD was equally efficient in resolving tetramolecular and bimolecular G4 DNA that were derived from the potential G4-forming sequences from the genome of E. coli Interestingly, in addition to resolving intermolecular G4 structures, EcUvrD was robust in unwinding intramolecular G4 structures. These data for the first time provide evidence for the role of UvrD in the resolution of G4 structures, which has implications for the in vivo role of UvrD helicase in G4 DNA resolution and genome maintenance. © 2017 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

Antibiotic resistant Salmonella and Escherichia coli isolated from ...

African Journals Online (AJOL)

Results: A hundred and four indigenous chicken rectal swabs were analysed, of which 67.3% were contaminated with Escherichia coli and 12.5% with Salmonella typhimurium. Seventy Escherichia coli isolates showed resistance phenotypes to one, two or more antibiotics. The most common antimicrobial resistance pattern ...

Fcγ receptor I alpha chain (CD64) expression in macrophages is critical for the onset of meningitis by Escherichia coli K1.

Science.gov (United States)

Mittal, Rahul; Sukumaran, Sunil K; Selvaraj, Suresh K; Wooster, David G; Babu, M Madan; Schreiber, Alan D; Verbeek, J Sjef; Prasadarao, Nemani V

2010-11-18

Neonatal meningitis due to Escherichia coli K1 is a serious illness with unchanged morbidity and mortality rates for the last few decades. The lack of a comprehensive understanding of the mechanisms involved in the development of meningitis contributes to this poor outcome. Here, we demonstrate that depletion of macrophages in newborn mice renders the animals resistant to E. coli K1 induced meningitis. The entry of E. coli K1 into macrophages requires the interaction of outer membrane protein A (OmpA) of E. coli K1 with the alpha chain of Fcγ receptor I (FcγRIa, CD64) for which IgG opsonization is not necessary. Overexpression of full-length but not C-terminal truncated FcγRIa in COS-1 cells permits E. coli K1 to enter the cells. Moreover, OmpA binding to FcγRIa prevents the recruitment of the γ-chain and induces a different pattern of tyrosine phosphorylation of macrophage proteins compared to IgG2a induced phosphorylation. Of note, FcγRIa(-/-) mice are resistant to E. coli infection due to accelerated clearance of bacteria from circulation, which in turn was the result of increased expression of CR3 on macrophages. Reintroduction of human FcγRIa in mouse FcγRIa(-/-) macrophages in vitro increased bacterial survival by suppressing the expression of CR3. Adoptive transfer of wild type macrophages into FcγRIa(-/-) mice restored susceptibility to E. coli infection. Together, these results show that the interaction of FcγRI alpha chain with OmpA plays a key role in the development of neonatal meningitis by E. coli K1.

Genetic and molecular analyses of Escherichia coli N-acetylneuraminate lyase gene.

OpenAIRE

Kawakami, B; Kudo, T; Narahashi, Y; Horikoshi, K

1986-01-01

Two plasmids containing the N-acetylneuraminate lyase (NALase) gene (nanA) of Escherichia coli, pNL1 and pNL4, were constructed. Immunoprecipitation analysis indicated that the 35,000-dalton protein encoded in pNL4 was NALase. The synthesis of NALase in E. coli carrying these plasmids was constitutive.

OXA-244-Producing Escherichia coli Isolates, a Challenge for Clinical Microbiology Laboratories.

Science.gov (United States)

Hoyos-Mallecot, Yannick; Naas, Thierry; Bonnin, Rémy A; Patino, Rafael; Glaser, Philippe; Fortineau, Nicolas; Dortet, Laurent

2017-09-01

OXA-244 is a single-point-mutant derivative of OXA-48 displaying reduced carbapenemase activity. Here, we report the microbiological features of seven OXA-244-producing Escherichia coli isolates. Only one isolate grew on ChromID Carba Smart medium (bioMérieux), but six of the seven isolates grew on ChromID extended-spectrum-β-lactamase (ESBL) medium (bioMérieux), as they coproduced an ESBL and/or a plasmid-encoded cephalosporinase. The production of a carbapenemase was detected in 57.1%, 71.4%, 71.4%, and 100% of the E. coli isolates using the Carba NP test, the Rapidec Carba NP test (bioMérieux), a matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) hydrolysis assay (Bruker), and the OXA-48 K-SeT assay (Coris BioConcept), respectively. Our results indicate that OXA-244-producing E. coli isolates are difficult to detect, which may lead to their silent spread. Copyright © 2017 American Society for Microbiology.

Biochemical Similarities and Differences between the Catalytic [4Fe-4S] Cluster Containing Fumarases FumA and FumB from Escherichia coli

NARCIS (Netherlands)

Van Vugt-Lussenburg, B.M.A.; Van der Weel, L.; Hagen, W.R.; Hagedoorn, P.L.

2013-01-01

Background: The highly homologous [4Fe-4S] containing fumarases FumA and FumB, sharing 90% amino acid sequence identity, from Escherichia coli are differentially regulated, which suggests a difference in their physiological function. The ratio of FumB over FumA expression levels increases by one to

[Aspects of the antimicrobial resistence profile in infections with Escherichia coli and Klebsiella pneumoniae in diabetic patients].

Science.gov (United States)

Petrovici, Cristina G; Dorobăţ, Carmen; Matei, Mioara; Teodor, Andra; Luca, V; Miftode, Egidia

2011-01-01

Infections in diabetic patient remains an important cause of morbidity and mortality, triggering and maintaining a prolonged metabolic imbalance. Emergence of extented spectrum beta-lactmase (ESBL) in Escherichia coli and Klebsiella pneumoniae is a major concern, because of the atypical manner infection acts in this group of imunodepressed patients and also for the limited therapeutic solutions. For this reason we have evaluated the profile of antimicrobial resistance of these pathogens in both diabetic and non diabetic patients. The aim of this study was to evaluate, in a retrospective case control study, the antibiotic susceptibility pattern in isolates of E. coli and Klebsiella spp. from different biological products in 49 diabetics and 150 non-diabetics admitted in The Clinical Hospital of Infectious Diseases Iaşi over a period of two years. Most of strains of E. coli and Klebsiella spp. ESBL positive were found in uroculture. Significant differences in E. coli resistance rate between diabetics and nondiabetics were noted for amoxicillin-clavulanic acid and ciprofloxacin (31,4% vs.13,98%, p=0,04, respectively 52,9% vs. 24,46%, p=0,004). More isolates of ESBL positive K. pneumoniae were found in diabetic patients (50% vs. 24%). Ciprofloxacin resistance of K. pneumoniae was significantly higher in diabetics (75% vs 39%; p=0,05). There was no resistance in E. coli and K. pneumoniae isolates to imipenem in the diabetic group. The high resistance rate to quinolones and 3rd generation cefalosporins limits their use for the treatment of Escherichia coli and K. pneumoniae infections. Other alternatives for empiric therapy in community and nosocomial-acquired infections in diabetic patient remains carbapenems, aminoglycosides and colimycin.

The gntP Gene of Escherichia coli Involved in Gluconate Uptake

DEFF Research Database (Denmark)

Klemm, Per; Tong, S.; Nielsen, Henrik

1996-01-01

The gntP gene, located between the fim and uxu loci in Escherichia coli K-12, has been cloned and characterized. Nucleotide sequencing of a region encompassing the gntP gene revealed an open reading frame of 447 codons with significant homology to the Bacillus subtilis gluconate permease. Northern...

MUREIN-METABOLIZING ENZYMES FROM ESCHERICHIA-COLI - EXISTENCE OF A 2ND LYTIC TRANSGLYCOSYLASE

NARCIS (Netherlands)

ENGEL, H; SMINK, AJ; VANWIJNGAARDEN, L; KECK, W

1992-01-01

In addition to the soluble lytic transglycosylase, a murein-metabolizing enzyme with a molecular mass of 70 kDa (Slt70), Escherichia coli possesses a second lytic transglycosylase, which has been described as a membrane-bound lytic transglycosylase (Mlt; 35 kDa; EC 3.2.1.-). The mlt gene, which

Pharmacokinetics of amoxicillin administered in drinking water to recently weaned 3- to 4-week-old pigs with diarrhea experimentally induced by Escherichia coli O149 : F4

DEFF Research Database (Denmark)

Jensen, G.M.; Lykkesfeldt, J.; Frydendahl, K.

2006-01-01

Objective-To measure effects of Escherichia coli 0149:F4-induced diarrhea on water consumption and pharmacokinetics of amoxicillin after administration in drinking water. Animals-24 recently weaned 24- to 28-day-old crossbred pigs. Procedure-10 pigs were inoculated with E coli O149:F4; all 10 pigs...... of amoxicillin may be appropriate for administration in drinking water during a 4-hour period on the first day that pigs have diarrhea attributable to E coli 0149:F4....

Fimbrial adhesins from extraintestinal Escherichia coli

DEFF Research Database (Denmark)

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

2010-01-01

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

In Vitro Assembly of the Outer Core of the Lipopolysaccharide from Escherichia coli K-12 and Salmonella typhimurium

Science.gov (United States)

2015-01-01

There are five distinct core structures in the lipopolysaccharides of Escherichia coli and at least two in Salmonella isolates, which vary principally in the outer core oligosaccharide. Six outer core glycosyltransferases, E. coli K-12 WaaG, WaaB, and WaaO and Salmonella typhimurium WaaI, WaaJ, and WaaK, were cloned, overexpressed, and purified. A novel substrate for WaaG was isolated from ΔwaaG E. coli overexpressing the lipid A phosphatase lpxE and the lipid A late acyltransferase lpxM. The action of lpxE and lpxM in the ΔwaaG background yielded heptose2-1-dephospho Kdo2-lipid A, a 1-dephosphorylated hexa-acylated lipid A with the inner core sugars that is easily isolated by organic extraction. Using this structurally defined acceptor and commercially available sugar nucleotides, each outer core glycosyltransferases was assayed in vitro. We show that WaaG and WaaB add a glucose and galactose sequentially to heptose2-1-dephospho Kdo2-lipid A. E. coli K-12 WaaO and S. typhimurium WaaI add a galactose to the WaaG/WaaB product but can also add a galactose to the WaaG product directly without the branched core sugar added by WaaB. Both WaaI and WaaO require divalent metal ions for optimal activity; however, WaaO, unlike WaaI, can add several glucose residues to its lipid acceptor. Using the product of WaaG, WaaB, and WaaI, we show that S. typhimurium WaaJ and WaaK transfer a glucose and N-acetylglucosamine, respectively, to yield the full outer core. This is the first demonstration of the in vitro assembly of the outer core of the lipopolysaccharide using defined lipid A-oligosaccharide acceptors and sugar donors. PMID:24479701

Effect of enrofloxacin treatment on plasma endotoxin during bovine Escherichia coli mastitis

NARCIS (Netherlands)

Dosogne, H.; Meyer, E.; Sturk, A.; van Loon, J.; Massart-Leën, A. M.; Burvenich, C.

2002-01-01

OBJECTIVE AND DESIGN: To investigate the effect of enrofloxacin on endotoxin resorption during bovine Escherichia coli mastitis. ANIMALS: 12 healthy early post partum Holstein cows. TREATMENT: Mastitis was induced by intramammary infusion of 10(4) cfu E. coli P4:032. Six cows were treated twice

Genomic and Phenomic Study of Mammary Pathogenic Escherichia coli

Science.gov (United States)

Blum, Shlomo E.; Heller, Elimelech D.; Sela, Shlomo; Elad, Daniel; Edery, Nir; Leitner, Gabriel

2015-01-01

Escherichia coli is a major etiological agent of intra-mammary infections (IMI) in cows, leading to acute mastitis and causing great economic losses in dairy production worldwide. Particular strains cause persistent IMI, leading to recurrent mastitis. Virulence factors of mammary pathogenic E. coli (MPEC) involved pathogenesis of mastitis as well as those differentiating strains causing acute or persistent mastitis are largely unknown. This study aimed to identify virulence markers in MPEC through whole genome and phenome comparative analysis. MPEC strains causing acute (VL2874 and P4) or persistent (VL2732) mastitis were compared to an environmental strain (K71) and to the genomes of strains representing different E. coli pathotypes. Intra-mammary challenge in mice confirmed experimentally that the strains studied here have different pathogenic potential, and that the environmental strain K71 is non-pathogenic in the mammary gland. Analysis of whole genome sequences and predicted proteomes revealed high similarity among MPEC, whereas MPEC significantly differed from the non-mammary pathogenic strain K71, and from E. coli genomes from other pathotypes. Functional features identified in MPEC genomes and lacking in the non-mammary pathogenic strain were associated with synthesis of lipopolysaccharide and other membrane antigens, ferric-dicitrate iron acquisition and sugars metabolism. Features associated with cytotoxicity or intra-cellular survival were found specifically in the genomes of strains from severe and acute (VL2874) or persistent (VL2732) mastitis, respectively. MPEC genomes were relatively similar to strain K-12, which was subsequently shown here to be possibly pathogenic in the mammary gland. Phenome analysis showed that the persistent MPEC was the most versatile in terms of nutrients metabolized and acute MPEC the least. Among phenotypes unique to MPEC compared to the non-mammary pathogenic strain were uric acid and D-serine metabolism. This study

Spread of avian pathogenic Escherichia coli ST117 O78:H4 in Nordic broiler production

DEFF Research Database (Denmark)

Ronco, Troels; Stegger, Marc; Olsen, Rikke Heidemann

2017-01-01

Escherichia coli infections known as colibacillosis constitute a considerable challenge to poultry farmers worldwide, in terms of decreased animal welfare and production economy. Colibacillosis is caused by avian pathogenic E. coli (APEC). APEC strains are extraintestinal pathogenic E. coli...... of isolates were collected from poultry with colibacillosis on Nordic farms. Subsequently, comparative genomic analyses were carried out. This included in silico typing (sero- and multi-locus sequence typing), identification of virulence and resistance genes and phylogenetic analyses based on single...... diseased broilers and breeders. The data indicate that the closely related ST117 O78:H4 strains have been transferred vertically through the broiler breeding pyramid into distantly located farms across the Nordic countries....

Epithelial Cell Adherence Mediated by the Enterotoxigenic Escherichia coli Tia Protein

OpenAIRE

Mammarappallil, Joseph G.; Elsinghorst, Eric A.

2000-01-01

In vitro studies have shown that enterotoxigenic Escherichia coli (ETEC) strains are capable of invading cultured epithelial cells derived from the human ileum and colon. Two separate invasion loci (tia and tib) have previously been isolated from the classical ETEC strain H10407. The tia locus has been shown to direct the synthesis of Tia, a 25-kDa outer membrane protein. Tia is sufficient to confer the adherence and invasion phenotypes on laboratory stains of E. coli, suggesting that this pr...

Complete Genome Sequence of Escherichia coli Strain WG5

DEFF Research Database (Denmark)

Imamovic, Lejla; Misiakou, Maria-Anna; van der Helm, Eric

2018-01-01

Escherichia coli strain WG5 is a widely used host for phage detection, including somatic coliphages employed as standard ISO method 10705-1 (2000). Here, we present the complete genome sequence of a commercial E. coli WG5 strain.......Escherichia coli strain WG5 is a widely used host for phage detection, including somatic coliphages employed as standard ISO method 10705-1 (2000). Here, we present the complete genome sequence of a commercial E. coli WG5 strain....

Building a complete image of genome regulation in the model organism Escherichia coli.

Science.gov (United States)

Ishihama, Akira

2018-01-15

The model organism, Escherichia coli, contains a total of more than 4,500 genes, but the total number of RNA polymerase (RNAP) core enzyme or the transcriptase is only about 2,000 molecules per genome. The regulatory targets of RNAP are, however, modulated by changing its promoter selectivity through two-steps of protein-protein interplay with 7 species of the sigma factor in the first step, and then 300 species of the transcription factor (TF) in the second step. Scientists working in the field of prokaryotic transcription in Japan have made considerable contributions to the elucidation of genetic frameworks and regulatory modes of the genome transcription in E. coli K-12. This review summarizes the findings by this group, first focusing on three sigma factors, the stationary-phase sigma RpoS, the heat-shock sigma RpoH, and the flagellar-chemotaxis sigma RpoF, as examples. It also presents an overview of the current state of the systematic research being carried out to identify the regulatory functions of all TFs from a single and the same bacterium E. coli K-12, using the genomic SELEX and PS-TF screening systems. All these studies have been undertaken with the aim of understanding the genome regulation in E. coli K-12 as a whole.

High-yield expression in Escherichia coli, purification and application of budding yeast K2 killer protein.

Science.gov (United States)

Podoliankaitė, Monika; Lukša, Juliana; Vyšniauskis, Gintautas; Sereikaitė, Jolanta; Melvydas, Vytautas; Serva, Saulius; Servienė, Elena

2014-07-01

Saccharomyces cerevisiae K2 toxin is a highly active extracellular protein, important as a biocontrol agent for biotechnological applications in the wine industry. This protein is produced at negligible levels in yeast, making difficult to isolate it in amounts sufficient for investigation and generation of analysis tools. In this work, we demonstrate the use of a bacterial system for expression of the recombinant K2 protein, suitable for generation of antibodies specific for toxin of the yeast origin. Synthesis of the full-length S. cerevisiae K2 preprotoxin in Escherichia coli was found to be toxic to the host cell, resulting in diminished growth. Such effect was abolished by the introduction of the C-terminal truncation into K2 protein, directing it into non-toxic inclusion body fraction. The obtained protein is of limited solubility thus, facilitating the purification by simple and efficient chromatography-free procedure. The protein aggregates were successfully refolded into a soluble form yielding sufficient amounts of a tag-less truncated K2 protein suitable for polyclonal antibody production. Antibodies were raised in rabbit and found to be specific for detection of both antigen and native S. cerevisiae K2 toxin.

Virulence factors of Escherichia coli in relation to the importance of vaccination in pigs

Directory of Open Access Journals (Sweden)

Daniele Araujo Pereira

2016-08-01

Full Text Available ABSTRACT: Enterotoxigenic Escherichia coli (ETEC is the major cause of diarrhea in newborn and weaned pigs. Bacteria adhesion to the host cell is considered a specific phenomenon among fimbrial and non-fimbrial adhesins with their respective receptors on enterocytes. Enteric disorders are related with the fimbriae F4 (K88, F5 (K99, F6 (987P, F41, and F18. In addition to ETEC, another category of E. coli , porcine pathogenic E. coli (PEPEC,can cause diarrhea in pigs; it produces the porcine attaching and effacing-associated (Paa adhesin in, which is capable to cause a typical lesion known as an attaching and effacing (A/E lesion. Immunization of sows with adhesin is important to stimulate the production of antibodies and their subsequent transfer to piglets through colostrum. The aim of this paper is to illustrate the main impacts of enteric diseases caused by E. coli in swine production and to highlight the importance of continuing research on this bacterium to improve disease prevention through vaccination.

High susceptibility prevalence for F4+ and F18+Escherichia coli in Flemish pigs.

Science.gov (United States)

Nguyen, Ut V; Coddens, Annelies; Melkebeek, Vesna; Devriendt, Bert; Goetstouwers, Tiphanie; Poucke, Mario Van; Peelman, Luc; Cox, Eric

2017-04-01

F4 and/or F18 enterotoxigenic Escherichia coli (F4 + /F18 + ETEC) are responsible for diarrhea while F18 + verotoxigenic E. coli (F18 + VTEC) cause edema disease in pigs. Both infections can result in severe economic losses, which are mainly the result of the medication, growth retardation and mortality. The susceptibility of piglets to these pathogens is determined by the presence of F4 and F18 receptors (F4R and F18R). Understanding the composition of the susceptibility phenotypes of pigs is useful for animal health and breeding management. This study aimed to determine the prevalence of the F4 ETEC susceptibility phenotypes and F18 + E. coli susceptibility among Flemish pig breeds by using the in vitro villous adhesion assay. In this study, seven F4 ETEC susceptibility phenotypes were found, namely A (F4 ab R + , ac R + , ad R + ; 59.16%), B (F4 ab R + , ac R + , ad R - ; 6.28%), C (F4 ab R + , ac R - , ad R + ; 2.62%), D (F4 ab R - , ac R - , ad R + ; 6.28%), E (F4 ab R - , ac R - , ad R - ; 24.08%), F (F4 ab R + , ac R - , ad R - ; 1.05%) and G (F4 ab R - , ac R + , ad R - ; 0.52%). F4ab and F4ac E. coli showed a stronger degree of adhesion to the intestinal villi (53.40% and 52.88% strong adhesion, respectively), compared to F4ad E. coli (43.46% strong adhesion). Furthermore, the correlation between F4ac and F4ab adhesion was higher (r=0.78) than between F4ac and F4ad adhesion (r=0.41) and between F4ab and F4ad adhesion (r=0.57). For F18 + E. coli susceptibility, seven out of 82 pigs were F18R negative (8.54%), but only two of these seven pigs (2.44%) were also negative for F4R. As such, the chance to identify a pig that is positive for a F4 ETEC variant or F18 + E. coli is 97.56%. Therefore, significant economic losses will arise due to F4 + and/or F18 + E. coli infections in the Flemish pig population due to the high susceptibility prevalence. Copyright © 2016 Elsevier B.V. All rights reserved.

99mTechnetium labelled Escherichia coli

International Nuclear Information System (INIS)

Diniz, S.O.F.; Cardoso, V.N.; Resende, B.M.; Nunan, E.A.; Simal, C.J.R.

1999-01-01

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

Identification of the Serratia marcescens hemolysin determinant by cloning into Escherichia coli

International Nuclear Information System (INIS)

Braun, V.; Neuss, B.; Ruan, Y.; Schiebel, E.; Schoeffler, H.; Jander, G.

1987-01-01

A cosmid bank of Serratia marcescens was established from which DNA fragments were cloned into the plasmid pBR322, which conferred the chromosomally encoded hemolytic activity to Escherichia coli K-12. By transposon mutagenesis with Tn1000 and Tn5 IS50/sub L/::phoA (TnphoA), the coding region was assigned to a DNA fragment, designated hyl, comprising approximately 7 kilobases. Two proteins with molecular weights of 61,000 (61K protein) and 160,000 (160K protein) were expressed by the pBR322 derivatives and by a plasmid which contained the hly genes under the control of a phage T7 promoter and the T7 RNA polymerase. When strongly overexpressed the 160K protein was released by E. coli cells into the extracellular medium concomitant with hemolytic activity. The genes encoding the 61K and the 160K proteins were transcribed in the same direction. Mutants expressing a 160K protein truncated at the carboxyl-terminal end were partially hemolytic. Hemolysis was progressively inhibited by saccharides with increasing molecular weights from maltotriose (M/sub r/ 504) to maltoheptaose (M/sub r/ 1152) and as totally abolished by dextran 4 (M/sub r/ 4000). This result and the observed influx of [ 14 C]sucrose into erythrocytes in the presence of hemolytic E. coli transformants under osmotically protective conditions suggest the formation of defined transmembrane channels by the hemolysin

Global functional atlas of Escherichia coli encompassing previously uncharacterized proteins.

Science.gov (United States)

Hu, Pingzhao; Janga, Sarath Chandra; Babu, Mohan; Díaz-Mejía, J Javier; Butland, Gareth; Yang, Wenhong; Pogoutse, Oxana; Guo, Xinghua; Phanse, Sadhna; Wong, Peter; Chandran, Shamanta; Christopoulos, Constantine; Nazarians-Armavil, Anaies; Nasseri, Negin Karimi; Musso, Gabriel; Ali, Mehrab; Nazemof, Nazila; Eroukova, Veronika; Golshani, Ashkan; Paccanaro, Alberto; Greenblatt, Jack F; Moreno-Hagelsieb, Gabriel; Emili, Andrew

2009-04-28

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

Establishing Streptomycin Epidemiological Cut-Off Values for Salmonella and Escherichia coli

DEFF Research Database (Denmark)

Migura, Lourdes Garcia; Sunde, Marianne; Karlsmose, Susanne

2011-01-01

This study was conducted to elucidate the accuracy of the current streptomycin epidemiological cut-off value (ECOFF) for Escherichia coli and Salmonella spp. A total of 236 Salmonella enterica and 208 E. coli isolates exhibiting MICs between 4 and 32 mg/L were selected from 12 countries. Isolates...

Asymptomatic bacteriuria Escherichia coli strains

DEFF Research Database (Denmark)

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

2006-01-01

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

Colonization of Enteroaggregative Escherichia coli and Shiga toxin-producing Escherichia coli in chickens and humans in southern Vietnam

NARCIS (Netherlands)

Trung, Nguyen Vinh; Nhung, Hoang Ngoc; Carrique-Mas, Juan J.; Mai, Ho Huynh; Tuyen, Ha Thanh; Campbell, James; Nhung, Nguyen Thi; van Minh, Pham; Wagenaar, Jaap A.; Mai, Nguyen Thi Nhu; Hieu, Thai Quoc; Schultsz, Constance; Hoa, Ngo Thi

2016-01-01

Enteroaggregative (EAEC) and Shiga-toxin producing Escherichia coli (STEC) are a major cause of diarrhea worldwide. E. coli carrying both virulence factors characteristic for EAEC and STEC and producing extended-spectrum beta-lactamase caused severe and protracted disease during an outbreak of E.

Purification and characterization of Desulfovibrio vulgaris (Hildenborough) hydrogenase expressed in Escherichia coli.

NARCIS (Netherlands)

Voordouw, G.; Hagen, W.R.; Kruse-Wolters, M.; Berkel-Arts, van A.; Veeger, C.

1987-01-01

Hydrogenase from Desulfovibrio vulgaris (Hildenborough) is a heterologous dimer of molecular mass 46 + 13.5 kDa. Its two structural genes have been cloned on a 4664-base-pair fragment of known sequence in the vector pUC9. Expression of hydrogenase polypeptides in Escherichia coli transformed with

Role of leader peptide synthesis in tryptophanase operon expression in Escherichia coli K-12.

OpenAIRE

Stewart, V; Yanofsky, C

1986-01-01

We used site-directed mutagenesis to replace the Escherichia coli tryptophanase (tna) operon leader peptide start codon with AUC. This change greatly decreased the uninduced rate of tna operon expression, and it also lowered the response to inducer. We conclude that leader peptide synthesis plays an essential role in tna operon expression.

Immunogenicity and protective efficacy of a single-dose live non-pathogenic Escherichia coli oral vaccine against F4-positive enterotoxigenic Escherichia coli challenge in pigs.

Science.gov (United States)

Fairbrother, John Morris; Nadeau, Éric; Bélanger, Louise; Tremblay, Cindy-Love; Tremblay, Danielle; Brunelle, Mélanie; Wolf, Regina; Hellmann, Klaus; Hidalgo, Álvaro

2017-01-05

Enterotoxigenic Escherichia coli strains expressing F4 (K88) fimbriae (F4-ETEC) are one of the most important causes of post-weaning diarrhea (PWD) in pigs. F4, a major antigen, plays an important role in the early steps of the infection. Herein, the efficacy of a live oral vaccine consisting of a non-pathogenic E. coli strain expressing F4 for protection of pigs against PWD was evaluated. Three blinded, placebo-controlled, block design, parallel-group confirmatory experiments were conducted, using an F4-ETEC PWD challenge model, each with a different vaccination-challenge interval (3, 7, and 21days). The pigs were vaccinated via the drinking water with a single dose of the Coliprotec® F4 vaccine one day post-weaning. Efficacy was assessed by evaluating diarrhea, clinical observations, intestinal fluid accumulation, weight gain, intestinal colonization and fecal shedding of F4-ETEC. The immune response was evaluated by measuring serum and intestinal F4-specific antibodies. The administration of the vaccine resulted in a significant reduction of the incidence of moderate to severe diarrhea, ileal colonization by F4-ETEC, and fecal shedding of F4-ETEC after the heterologous challenge at 7 and 21days post-vaccination. The 7-day onset of protection was associated with an increase of serum anti-F4 IgM whereas the 21-day duration of protection was associated with an increase of both serum anti-F4 IgM and IgA. Significant correlations between levels of serum and intestinal secretory anti-F4 antibodies were detected. Maternally derived F4-specific serum antibodies did not interfere with the vaccine efficacy. The evaluation of protection following a challenge three days after vaccination showed a reduction of the severity and the duration of diarrhea and of fecal shedding of F4-ETEC. The 7-day onset and the 21-day duration of protection induced by Coliprotec® F4 vaccine administered once in drinking water to pigs of at least 18days of age were confirmed by protection

Characterization of Escherichia coli Phylogenetic Groups ...

African Journals Online (AJOL)

Background: Escherichia coli strains mainly fall into four phylogenetic groups (A, B1, B2, and D) and that virulent extra‑intestinal strains mainly belong to groups B2 and D. Aim: The aim was to determine the association between phylogenetic groups of E. coli causing extraintestinal infections (ExPEC) regarding the site of ...

WGS accurately predicts antimicrobial resistance in Escherichia coli

Science.gov (United States)

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...

GroEL and dnaK genes of Escherichia coli are induced by UV irradiation and nalidixic acid in an htpR+-dependent fashion

International Nuclear Information System (INIS)

Krueger, J.H.; Walker, G.C.

1984-01-01

Two proteins with molecular weights of 61,000 and 73,000 were found to be induced by UV light in Escherichia coli mutants in which the SOS responses are constitutively expressed. The induction of these proteins by UV light and nalidixic acid was shown to be independent of the recA + lexA + regulatory system. Analysis of these proteins by two-dimensional gel electrophoresis and comparison with the heat-shock proteins of E. coli revealed that the M/sub r/ 61,000 protein comigrated with the groEL gene product, that the M/sub r/ 73,000 protein comigrated with the dnaK gene product, and that other heat-shock proteins were also induced. The induction of groEL and dnaK by UV light and nalidixic acid is controlled by the htpR locus. The results suggest that the regulatory response of E. coli to agents such as UV light and nalidixic acid is more complex than previously thought. 35 references, 6 figures, 1 table

Expression of ultraviolet-induced restriction alleviation in Escherichia coli K-12

International Nuclear Information System (INIS)

Thoms, B.; Wackernagel, W.

1983-01-01

Ultraviolet-induced restriction alleviation is an SOS function which partially relieves the K-12-specific DNA restriction in Escherichia coli. Restriction alleviation is determined by observing elevated survival of unmodified phage lambda in cells irradiated with ultraviolet prior to infection. The authors demonstrate that restriction of lambda is also relieved when log-phase cells are irradiated as late as 50 min after adsorption of lambda. At this time more than 60% of the lambda DNA is already released as acid-soluble material from the cells. Experiments involving reextraction of lambda DNA from infected cells and a mild detergent treatment removing adsorbed phages from the cellular surface showed that only a small specific fraction of all lambda infections is destined to escape restriction due to restriction alleviation. This fraction (10-20%) has a retarded mode of DNA injection (60 min or longer) after adsorption which allows the expression of the restriction alleviation function before the phage DNA is exposed to restriction endonucleases. This behaviour of a fraction of lambda phages explains why the SOS function restriction alleviation could initially be discovered. The authors show that the retarded mode of DNA injection is not required for another SOS function acting on lambda DNA, the increased repair of ultraviolet-irradiated DNA (Weigle reactivation). (Auth.)

F4+ enterotoxigenic Escherichia coli (ETEC) adhesion mediated by the major fimbrial subunit FaeG.

Science.gov (United States)

Xia, Pengpeng; Song, Yujie; Zou, Yajie; Yang, Ying; Zhu, Guoqiang

2015-09-01

The FaeG subunit is the major constituent of F4(+) fimbriae, associated with glycoprotein and/or glycolipid receptor recognition and majorly contributes to the pathogen attachment to the host cells. To investigate the key factor involved in the fimbrial binding of F4(+) Escherichia coli, both the recombinant E. coli SE5000 strains carrying the fae operon gene clusters that express the different types of fimbriae in vitro, named as rF4ab, rF4ac, and rF4ad, respectively, corresponding to the fimbrial types F4ab, F4ac, and F4ad, and the three isogenic in-frame faeG gene deletion mutants were constructed. The adhesion assays and adhesion inhibition assays showed that ΔfaeG mutants had a significant reduction in the binding to porcine brush border as well as the intestinal epithelial cell lines, while the complemented strain ΔfaeG/pfaeG restored the adhesion function. The recombinant bacterial strains rF4ab, rF4ac, and rF4ad have the same binding property as wild-type F4(+) E. coli strains do and improvement in terms of binding to porcine brush border and the intestinal epithelial cells, and the adherence was blocked by the monoclonal antibody anti-F4 fimbriae. These data demonstrate that the fimbrial binding of F4(+) E. coli is directly mediated by the major FaeG subunit. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Dietary addition of Lactobacillus rhamnosus GG impairs the health of Escherichia coli F4-challenged piglets.

Science.gov (United States)

Trevisi, P; Casini, L; Coloretti, F; Mazzoni, M; Merialdi, G; Bosi, P

2011-08-01

Lactobacillus rhamnosus GG (LGG) is a probiotic for humans and is normally not found in pigs; however, it has been shown to protect the human-derived intestinal Caco-2 cells against the damage induced by an important intestinal pathogen, enterotoxigenic Escherichia coli F4 (ETEC). An experiment was conducted to test whether the dietary addition of LGG improves the growth and health of weaned pigs when orally challenged by E. coli F4. Thirty-six pigs were weaned at 21 days and assigned to a standard weaning diet with or without 1010 CFU LGG (ATCC 53103) per day. The pigs, individually penned, were orally challenged with 1.5 ml of a 1010 CFU E. coli F4 suspension on day 7 and slaughtered on day 12 or 14. With the addition of LGG, the average daily gain and the average daily feed intake were reduced after the challenge with ETEC and for the entire trial (P F4-specific IgA activity was not affected by the diet at all the samplings. Our result shows that, the administration of LGG do not prevent or reduce the detrimental effect of the E. coli F4 infection on the growth performance and health status of weaned piglet.

Refined localization of the Escherichia coli F4ab/F4ac receptor locus on pig chromosome 13

DEFF Research Database (Denmark)

Joller, D.; Jørgensen, Claus Bøttcher; Bertschinger, H.U.

2009-01-01

Diarrhoea in newborn and weaned pigs caused by enterotoxigenic Escherichia coli (ETEC) expressing F4 fimbriae leads to considerable losses in pig production. In this study, we refined the mapping of the receptor locus for ETEC F4ab/F4ac adhesion (F4bcR) by joint analysis of Nordic and Swiss data...... (MUC4-8227) were used to create the linkage map. The region for F4bcR was refined to the interval SW207-S0075 on pig chromosome 13. The most probable position of F4bcR was in the SW207-MUC4 region. The order of six markers was supported by physical mapping on the BAC fingerprint contig from...

Transport of Escherichia coli phage through saturated porous media considering managed aquifer recharge.

Science.gov (United States)

Zhang, Wenjing; Li, Shuo; Wang, Shuang; Lei, Liancheng; Yu, Xipeng; Ma, Tianyi

2018-03-01

Virus is one of the most potentially harmful microorganisms in groundwater. In this paper, the effects of hydrodynamic and hydrogeochemical conditions on the transportation of the colloidal virus considering managed aquifer recharge were systematically investigated. Escherichia coli phage, vB_EcoM-ep3, has a broad host range and was able to lyse pathogenic Escherichia coli. Bacteriophage with low risk to infect human has been found extensively in the groundwater environment, so it is considered as a representative model of groundwater viruses. Laboratory studies were carried out to analyze the transport of the Escherichia coli phage under varying conditions of pH, ionic strength, cation valence, flow rate, porous media, and phosphate buffer concentration. The results indicated that decreasing the pH will increase the adsorption of Escherichia coli phage. Increasing the ionic strength, either Na + or Ca 2+ , will form negative condition for the migration of Escherichia coli phage. A comparison of different cation valence tests indicated that changes in transport and deposition were more pronounced with divalent Ca 2+ than monovalent Na + . As the flow rate increases, the release of Escherichia coli phage increases and the retention of Escherichia coli phage in the aquifer medium reduces. Changes in porous media had a significant effect on Escherichia coli phage migration. With increase of phosphate buffer concentration, the suspension stability and migration ability of Escherichia coli phage are both increased. Based on laboratory-scale column experiments, a one-dimensional transport model was established to quantitatively describe the virus transport in saturated porous medium.

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

Science.gov (United States)

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

Escherichia coli survival in waters: Temperature dependence

Science.gov (United States)

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...

Immunochemical determination of cellular content of translation release factor RF4 in Escherichia coli

DEFF Research Database (Denmark)

Andersen, Lars Dyrskjøt; Manuel Palacios Moreno, Juan; Clark, Brian F. C.

1999-01-01

of the stop codons, and RF3 is known to accelerate the overall termination process. Release factor RF4 is a protein involved in the release of the mRNA and tRNA from the ribosomal complex. Furthermore, RF4 is involved in the proofreading in the elongation step of protein biosynthesis. The cellular contents...... of RF1, RF2, and RF3 were determined earlier. Here we report the cellular content of RF4 in Escherichia coli to be approximately 16,500 molecules per cell. The cells were grown in a rich medium and harvested in the beginning of the exponential growth phase. The quantifications were performed by using...

Vascular Endothelial Growth Factor Receptor 1 Contributes to Escherichia coli K1 Invasion of Human Brain Microvascular Endothelial Cells through the Phosphatidylinositol 3-Kinase/Akt Signaling Pathway▿ †

OpenAIRE

Zhao, Wei-Dong; Liu, Wei; Fang, Wen-Gang; Kim, Kwang Sik; Chen, Yu-Hua

2010-01-01

Escherichia coli is the most common Gram-negative organism causing neonatal meningitis. Previous studies demonstrated that E. coli K1 invasion of brain microvascular endothelial cells (BMEC) is required for penetration into the central nervous system, but the microbe-host interactions that are involved in this process remain incompletely understood. Here we report the involvement of vascular endothelial growth factor receptor 1 (VEGFR1) expressed on human brain microvascular endothelial cells...

Succinic acid production by escherichia coli under anaerobic fermentation

International Nuclear Information System (INIS)

El Shafey, H.M.; Meleigy, S.A.

2009-01-01

The effect of alteration of growth conditions, addition of different sodium salts, and irradiation by gamma rays on succinic acid production by E. coli was studied. Twenty one isolates were obtained from buffalo's rumen, and anaerobic screening of the isolated bacterial strains showed the abilities of seventeen strains to produce succinic acid. The two bacterial strains having highest succinic acid production were identified as escherichia coli SP9 and SP16, and were selected for further studies. Results showed that growth conditions yielded highest succinic acid production for the two isolates were: 72 hours incubation, 37 degree c incubation temperature, initial ph of the fermentation medium 6.0,and 3% (v/v)inoculum size. Addition of 5 mm of nine different sodium salts to the fermentation medium showed stimulating effect on succinic acid production of the nine tried sodium salts, sodium carbonate was found to have the highest enhancing effect, especially if used at 15 mm concentration. Gamma irradiation doses tried were in the range of (0.25-1.50 kGy). An enhancing effect on succinic acid production was shown in the range of 0.25-0.75 kGy with a maximal production at 0.75 kGy (giving 8.36% increase) for e.coli SP9, and in the range of 0.25-1.00 kGy with a maximal production at 1.0 kGy (7.60% increase) for e.coli SP16. higher gamma doses led to a decrease in the enhancing effect. An overall increase in the succinic acid yield of 79.45% and 94.26% for e. coli SP9 and SP16, respectively, was achieved in implicating all optimized factors for succinic acid production in one time

Production of caffeoylmalic acid from glucose in engineered Escherichia coli.

Science.gov (United States)

Li, Tianzhen; Zhou, Wei; Bi, Huiping; Zhuang, Yibin; Zhang, Tongcun; Liu, Tao

2018-07-01

To achieve biosynthesis of caffeoylmalic acid from glucose in engineered Escherichia coli. We constructed the biosynthetic pathway of caffeoylmalic acid in E. coli by co-expression of heterologous genes RgTAL, HpaBC, At4CL2 and HCT2. To enhance the production of caffeoylmalic acid, we optimized the tyrosine metabolic pathway of E. coli to increase the supply of the substrate caffeic acid. Consequently, an E. coli-E. coli co-culture system was used for the efficient production of caffeoylmalic acid. The final titer of caffeoylmalic acid reached 570.1 mg/L. Microbial production of caffeoylmalic acid using glucose has application potential. In addition, microbial co-culture is an efficient tool for producing caffeic acid esters.

Induction of the lambda bacteriophage synthesis in Escherichia coli K 12 by polonium alpha rays

International Nuclear Information System (INIS)

Devoret, Raymond

1958-06-01

This research thesis reports the study of the inducing action of polonium alpha radiations in Escherichia Coli K 12 by using an external irradiation device. This work comprised the development of a method to spread bacteria in layer with a thickness less than 20 microns, and the measurement of the number of α particles falling on the irradiated surface. This measurement has been performed by using a nuclear emulsion and a simple photographic film. It appears that alpha radiations have an inducing action, and that at most 15 per cent of bacteria can be induced. The comparison of the induction curve with the survival curves of lysogen and sensitive stains shows that there is no abortive induction. Thus, it appears that this inducing action is not due to an indirect effect of the irradiated medium [fr

Accurate differentiation of Escherichia coli and Shigella serogroups: challenges and strategies

Directory of Open Access Journals (Sweden)

N.K. Devanga Ragupathi

2018-01-01

Full Text Available Shigella spp. and Escherichia coli are closely related; both belong to the family Enterobacteriaceae. Phenotypically, Shigella spp. and E. coli share many common characteristics, yet they have separate entities in epidemiology and clinical disease, which poses a diagnostic challenge. We collated information for the best possible approach to differentiate clinically relevant E. coli from Shigella spp. We found that a molecular approach is required for confirmation. High discriminatory potential is seen with whole genome sequencing analysed for k-mers and single nucleotide polymorphism. Among these, identification using single nucleotide polymorphism is easy to perform and analyse, and it thus appears more promising. Among the nonmolecular methods, matrix-assisted desorption ionization–time of flight mass spectrometry may be applicable when data analysis is assisted with advanced analytic tools. Keywords: 16S rRNA, k-mer, MALDI-TOF MS, single nucleotide polymorphism, whole genome sequencing

Comparison of 61 Sequenced Escherichia coli Genomes

DEFF Research Database (Denmark)

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

2010-01-01

Escherichia coli is an important component of the biosphere and is an ideal model for studies of processes involved in bacterial genome evolution. Sixty-one publically available E. coli and Shigella spp. sequenced genomes are compared, using basic methods to produce phylogenetic and proteomics...

lactamase in clinical isolates of Escherichia coli

African Journals Online (AJOL)

Jane

2011-08-22

Aug 22, 2011 ... The beta lactamase enzyme producing E. coli, resistant to β-lactam antibiotics, created many problems ... Key words: Escherichia coli, β-lactamase enzymes, TEM-type extended spectrum ... difficulties in treatment using antibiotics that are currently ... and chloramphenicol (30 µg) (Mast Diagnostics Ltd., UK).

The antibacterial effect of four mouthwashes against streptococcus mutans and escherichia coli.

Science.gov (United States)

Ghapanchi, Janan; Lavaee, Fatemeh; Moattari, Afagh; Shakib, Mahmood

2015-04-01

To evaluate the antimicrobial properties of several mouthwash concentrations on oral Streptococcus mutans and Escherichia coli. The study was conducted at Shiraz Medicine School in 2011. Serial dilutions of Chlorohexidin, Oral B and Persica and Irsha (2,4,8,16,64,128) were prepared in Muller-Hinton media. Minimum inhibitory concentration was visually determined and defined as the lowest concentration of each oral washing which inhibited > 95% growth reduction compared to the growth control well. Chlorhexidine, Oral B and Irsha mouthwash inhibited Streptococcus mutans even with diluted concentrations. Also, Chlorhexidine and Oral B prohibited Escherichia coli with different potencies. But Persica had no antimicrobial activity against either Escherichia coli or Streptococcus mutans. Chlorhexidine, Irsha, and Oral B mouthwashes can be used for antimicrobial effects, especially on Streptococcus mutans. This chemical activity of mouthwashes is an adjuvant for mechanical removing of plaque. However, the antimicrobial effect of Persicaremains controversial.

Extended-spectrum β-lactamase (ESBL) in Danish clinical isolates of Escherichia coli and Klebsiella pneumoniae

DEFF Research Database (Denmark)

Hansen, Dennis Schrøder; Schumacher, Helga; Hansen, Frank

2012-01-01

Most Gram-negative community-acquired and nosocomial infections are caused by Escherichia coli and Klebsiella pneumoniae, among which increasing resistance due to extended-spectrum β-lactamase (ESBL) is a major problem. We present data from the first Danish nationwide prevalence study on ESBL-pro......-producing E. coli, K. pneumoniae, and Proteus mirabilis in blood and urine cultures from hospitals and the community....

The mechanism of uncoupling by picrate in Escherichia coli K-12 membrane systems.

Science.gov (United States)

Michels, M; Bakker, E P

1981-06-01

The mechanism of action of the uncoupler picrate on intact cells and everted membrane vesicles of Escherichia coli K-12 was investigated. Like in mitochondria [Hanstein, W. G. and Hatefi, Y. (1974) Proc. Natl Acad. Sci. USA, 71, 288-292], it was observed that picrate uncoupled energy-linked functions only in everted, but not in intact membrane systems. In the vesicles picrate also decreased the magnitude of the transmembrane proton-motive force at concentrations similar to those at which it caused uncoupling. Experiments with 14C-labelled picrate showed that this compound bound both to deenergized intact cells and everted vesicles. However, upon energization of the membrane, picrate was extruded from the intact cell and taken up to a larger extent by the vesicles. These energy-dependent changes in picrate uptake correlated with the magnitude of the transmembrane electrical potential, delta psi. It is therefore proposed that picrate is a permeant uncoupler, that delta psi is the driving force for picrate movement across biological membranes, and that the uncoupling activity of picrate in everted membrane systems is due to its protonophoric action.

Structural studies on some capsular antigens from Escherichia Coli and Klebsiella

Energy Technology Data Exchange (ETDEWEB)

Anderson, A N

1987-12-01

A review of the structural studies of bacterial capsular polysaccharides (K-antigens) from Escherichia coli (E.coli) and Klebsiella is presented. There is a general trend in the structural elucidation of polysaccharides towards the analysis of higher oligosaccharides. This trend has been facilitated by advances in modern instrumental techniques for the analysis of oligosaccharides, for example, high-performance liquid chromatography, mass spectometry and nuclear magnetic resonance spectroscopy. The structural elucidations of the capsular polysaccharides from E. Coli K37 and K55, and Klebsiella K39 are reported. This elucidation of K-antigens provides an insight into the response of mammalian immune systems to antigenic stimuli. The usefulness of bacteriophage degradation as a technique for the structural elucidation of polysaccharides containing repeating unit structures is emphasized. The bacteriophage degradation of E. coli K55 polysaccharide illustrates that bacteriophage-borne enzymes may be used to degrade chemically related carbohydrate materials. The bacteriophage technique for the structural elucidation of the Klebsiella K39 polysaccharide also illustrates the advantages of this technique where the polysaccharide contains labile glycosidic bonds which are readily cleaved during standard chemical analysis. The enzymatic degradation of polysaccharides allows high yields of specific oligosaccharides to be recovered. The feasibility of analysing small amounts of carbohydrate material has become realistic due to improved instrumental capabilities. At the same time, more detailed information concerning the fine structure of known carbohydrate materials can be elucidated. 421 refs., 56 figs., 16 tabs.

Altered Escherichia coli membrane protein assembly machinery allows proper membrane assembly of eukaryotic protein vitamin K epoxide reductase.

Science.gov (United States)

Hatahet, Feras; Blazyk, Jessica L; Martineau, Eugenie; Mandela, Eric; Zhao, Yongxin; Campbell, Robert E; Beckwith, Jonathan; Boyd, Dana

2015-12-08

Functional overexpression of polytopic membrane proteins, particularly when in a foreign host, is often a challenging task. Factors that negatively affect such processes are poorly understood. Using the mammalian membrane protein vitamin K epoxide reductase (VKORc1) as a reporter, we describe a genetic selection approach allowing the isolation of Escherichia coli mutants capable of functionally expressing this blood-coagulation enzyme. The isolated mutants map to components of membrane protein assembly and quality control proteins YidC and HslV. We show that changes in the VKORc1 sequence and in the YidC hydrophilic groove along with the inactivation of HslV promote VKORc1 activity and dramatically increase its expression level. We hypothesize that such changes correct for mismatches in the membrane topogenic signals between E. coli and eukaryotic cells guiding proper membrane integration. Furthermore, the obtained mutants allow the study of VKORc1 reaction mechanisms, inhibition by warfarin, and the high-throughput screening for potential anticoagulants.

Characterization of diarrhoeagenic Escherichia coli isolates in Jordanian children.

Science.gov (United States)

Shehabi, Asem A; Bulos, Najawa-Kuri; Hajjaj, Kamal G

2003-01-01

In a prospective study carried out among Jordanian children in Amman, a total of 73/250 (29.2%) stool specimens were positive for 1 or more diarrhoeagenic Escherichia coli strains using a multiplex polymerase chain reaction method. This study indicated that diarrhoeagenic E. coli isolates were found frequently more in stools of children with diarrhoea (34%) than without diarrhoea (23.1%), but without any significant difference (p > 0.05). The predominant diarrhoeagenic E. coli strains associated with diarrhoea were enteropathogenic E. coli (11.3%), followed by enterotoxigenic E. coli (9.8%) and enteroaggrative E. coli (9%), whereas in the control group these were 4.3%, 11.1% and 6%, respectively. Enteroinvasive E. coli strains (2.9%) were found only in stools of children with diarrhoea. This study revealed the absence of enterohaemorrhagic E. coli in both diarrhoeal and control stools, and found that diarrhoeagenic E. coli isolates were highly resistance to tetracycline (55%), co-trimoxazole (60%) and ampicillin (89%), which are commonly used antibiotics in Jordan.

Characterization of Escherichia coli Phylogenetic Groups ...

African Journals Online (AJOL)

tract infection (UTI), bacteremia, pneumonia, soft-tissue infection, and ... Keywords: Drug resistance, Escherichia coli, Extraintestinal infections, Polymerase chain reaction, .... gynecology, 12 from orthopedics and 5 from pediatrics units.

Effect of incubation temperatures for inactivation of Escherichia coli and related bacteria after gamma-irradiation

International Nuclear Information System (INIS)

Nakauma, Makoto; Ito, Hitoshi; Tada, Mikiro

2000-01-01

Irradiated fresh meat or fishery products have been expected to store and distribute under refrigerated temperature below 10degC. From previous reports, growth of coliform bacteria in these products were suppressed by gamma-irradiation below expected doses obtained at 30-37degC. This research was performed to observe the irradiation effect on the inactivation of Escherichia coli and related bacteria at different incubation temperatures of 10-40degC on plate agar after irradiation. From this study, D10 values of all strains decreased 17- 45% at 10degC compared with maximum D10 values at 30- 40degC. Radiation sensitivities were related to the ability to grow at low temperatures in which psychrotrophic type E. coli A4-1 indicated most sensitive to radiation, next of Salmonella enteritidis YK-2, E. coli S2, B4 whereas most resistant at Enterobacter agglomerans K3-1. (author)

Effect of incubation temperatures for inactivation of Escherichia coli and related bacteria after gamma-irradiation

Energy Technology Data Exchange (ETDEWEB)

Nakauma, Makoto; Ito, Hitoshi [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment; Tada, Mikiro [Okayama Univ. (Japan). Faculty of Agriculture

2000-09-01

Irradiated fresh meat or fishery products have been expected to store and distribute under refrigerated temperature below 10degC. From previous reports, growth of coliform bacteria in these products were suppressed by gamma-irradiation below expected doses obtained at 30-37degC. This research was performed to observe the irradiation effect on the inactivation of Escherichia coli and related bacteria at different incubation temperatures of 10-40degC on plate agar after irradiation. From this study, D10 values of all strains decreased 17- 45% at 10degC compared with maximum D10 values at 30- 40degC. Radiation sensitivities were related to the ability to grow at low temperatures in which psychrotrophic type E. coli A4-1 indicated most sensitive to radiation, next of Salmonella enteritidis YK-2, E. coli S2, B4 whereas most resistant at Enterobacter agglomerans K3-1. (author)

Affinity isolation and I-DIRT mass spectrometric analysis of the Escherichia coli O157:H7 Sakai RNA polymerase complex.

Science.gov (United States)

Lee, David J; Busby, Stephen J W; Westblade, Lars F; Chait, Brian T

2008-02-01

Bacteria contain a single multisubunit RNA polymerase that is responsible for the synthesis of all RNA. Previous studies of the Escherichia coli K-12 laboratory strain identified a group of effector proteins that interact directly with RNA polymerase to modulate the efficiency of transcription initiation, elongation, or termination. Here we used a rapid affinity isolation technique to isolate RNA polymerase from the pathogenic Escherichia coli strain O157:H7 Sakai. We analyzed the RNA polymerase enzyme complex using mass spectrometry and identified associated proteins. Although E. coli O157:H7 Sakai contains more than 1,600 genes not present in the K-12 strain, many of which are predicted to be involved in transcription regulation, all of the identified proteins in this study were encoded on the "core" E. coli genome.

Global functional atlas of Escherichia coli encompassing previously uncharacterized proteins.

Directory of Open Access Journals (Sweden)

Pingzhao Hu

2009-04-01

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

Regulation of Toll-like receptor 2 interaction with Ecgp96 controls Escherichia coli K1 invasion of brain endothelial cells

OpenAIRE

Krishnan, Subramanian; Chen, Shuang; Turcatel, Gianluca; Arditi, Moshe; Prasadarao, Nemani V.

2012-01-01

The interaction of outer membrane protein A (OmpA) with its receptor, Ecgp96 (a homologue of Hsp90β) is critical for the pathogenesis of E. coli K1 meningitis. Since Hsp90 chaperones Toll-like receptors (TLRs), we examined the role of TLRs in E. coli K1 infection. Herein, we show that newborn TLR2−/− mice are resistant to E. coli K1 meningitis, while TLR4−/− mice succumb to infection sooner. In vitro, OmpA+ E. coli infection selectively upregulates Ecgp96 and TLR2 in human brain microvascular...

Biomolecular Mechanisms of Pseudomonas aeruginosa and Escherichia coli Biofilm Formation

Science.gov (United States)

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

2014-01-01

Pseudomonas aeruginosa and Escherichia coli are the most prevalent Gram-negative biofilm forming medical device associated pathogens, particularly with respect to catheter associated urinary tract infections. In a similar manner to Gram-positive bacteria, Gram-negative biofilm formation is fundamentally determined by a series of steps outlined more fully in this review, namely adhesion, cellular aggregation, and the production of an extracellular polymeric matrix. More specifically this review will explore the biosynthesis and role of pili and flagella in Gram-negative adhesion and accumulation on surfaces in Pseudomonas aeruginosa and Escherichia coli. The process of biofilm maturation is compared and contrasted in both species, namely the production of the exopolysaccharides via the polysaccharide synthesis locus (Psl), pellicle Formation (Pel) and alginic acid synthesis in Pseudomonas aeruginosa, and UDP-4-amino-4-deoxy-l-arabinose and colonic acid synthesis in Escherichia coli. An emphasis is placed on the importance of the LuxR homologue sdiA; the luxS/autoinducer-II; an autoinducer-III/epinephrine/norepinephrine and indole mediated Quorum sensing systems in enabling Gram-negative bacteria to adapt to their environments. The majority of Gram-negative biofilms consist of polysaccharides of a simple sugar structure (either homo- or heteropolysaccharides) that provide an optimum environment for the survival and maturation of bacteria, allowing them to display increased resistance to antibiotics and predation. PMID:25438014

Biomolecular Mechanisms of Pseudomonas aeruginosa and Escherichia coli Biofilm Formation

Directory of Open Access Journals (Sweden)

Garry Laverty

2014-07-01

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

Plasmid-Mediated Quinolone Resistance Genes in Escherichia coli ...

African Journals Online (AJOL)

Erah

PMQR) genes and the prevalence of extended spectrum β-lactamase (ESBL) types in Escherichia coli clinical isolates. Methods: Sixty-one ESBL-producing urinary E. coli isolates were studied. An antibiotic susceptibility test was performed ...

Antimicrobial resistance among commensal Escherichia coli from ...

African Journals Online (AJOL)

Commensal bacteria contribute to the distribution and persistence of antimicrobial resistance in the environment. This study monitored antimicrobial resistance in commensal Escherichia coli from the faeces of on-farm and slaughter cattle and beef. A total of 342 (89.5%) E. coli isolates were obtained from 382 samples.

Antimicrobial resistance among commensal Escherichia coli from ...

African Journals Online (AJOL)

user1

2012-07-19

Jul 19, 2012 ... Commensal bacteria contribute to the distribution and persistence of antimicrobial resistance in the environment. This study monitored antimicrobial resistance in commensal Escherichia coli from the faeces of on-farm and slaughter cattle and beef. A total of 342 (89.5%) E. coli isolates were obtained.

Refined candidate region specified by haplotype sharing for Escherichia coli F4ab/F4ac susceptibility alleles in pigs

DEFF Research Database (Denmark)

Jacobsen, Mette Juul; Kracht, Steffen Skaarup; Esteso, G.

2009-01-01

Infection of the small intestine by enterotoxigenic Escherichia coli F4ab/ac is a major welfare problem and financial burden for the pig industry. Natural resistance to this infection is inherited as a Mendelian recessive trait, and a polymorphism in the MUC4 gene segregating for susceptibility....../resistance is presently used in a selection programme by the Danish pig breeding industry. To elucidate the genetic background involved in E. coli F4ab/ac susceptibility in pigs, a detailed haplotype map of the porcine candidate region was established. This region covers approximately 3.7 Mb. The material used...... for the study is a three generation family, where the founders are two Wild boars and eight Large White sows. All pigs have been phenotyped for susceptibility to F4ab/ac using an adhesion assay. Their haplotypes are known from segregation analysis using flanking markes. By a targeted approach, the candidate...

Feeding of Lactobacillus sobrius reduces Escherichia coli F4 levels in the gut and promotes growth of infected piglets

NARCIS (Netherlands)

Konstantinov, S.R.; Smidt, H.; Akkermans, A.D.L.; Casini, L.; Trevisi, P.; Mazzoni, M.; Filippi, de S.; Bosi, P.; Vos, de W.M.

2008-01-01

The microbial community in the guts of mammals is often seen as an important potential target in therapeutic and preventive interventions. The aim of the present study was to determine whether enterotoxigenic Escherichia coli (ETEC) F4 infection in young animals might be counteracted by a probiotic

Inactivation of Escherichia coli in soil by solarization

International Nuclear Information System (INIS)

Wu, S.; Nishihara, M.; Kawasaki, Y.; Yokoyama, A.; Matsuura, K.; Koga, T.; Ueno, D.; Inoue, K.; Someya, T.

2009-01-01

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

Correlation between survival, ability to rejoin DNA and stability of DNA after preirradiation inhibition of protein synthesis in a rec- mutant of Escherichia coli K12

International Nuclear Information System (INIS)

Pirsel, M.; Slezarikova, V.

1977-01-01

A 90 min inhibition of protein synthesis induced by starvation for amino acids (AA - ) or by chloramphenicol (CAP) treatment prior to UV irradiation (2.5 J m -2 ) increased more than tenfold the resistance of the strain Escherichia coli K12 SR19 to UV radiation. Under these conditions, cultures in which protein synthesis was inhibited before the UV irradiation rejoin short regions of DNA synthesized after the irradiation to a normal-size molecule, whereas an exponentially growing culture does not rejoin DNA synthesized after UV irradiation to a molecule of a normal size. In the exponentially growing culture both the parental and the newly synthesized DNA are unstable after the irradiation. In cultures with inhibited protein synthesis only the parental DNA is somewhat unstable. In Escherichia coli K12 SR19 where protein synthesis was inhibited before the irradiation, a correlation between the survival of cells, the ability to rejoin short regions of DNA synthesized after UV irradiation, and a higher stability of both parental and newly synthesized DNAs could be demonstrated. (author)

Reduction of Escherichia coli 0157:H7 in shredded iceberg lettuce by chlorination and gamma irradiation

Energy Technology Data Exchange (ETDEWEB)

Foley, D.M. E-mail: dfoley@chapman.edu; Dufour, A.; Rodriguez, L.; Caporaso, F.; Prakash, A

2002-03-01

Lettuce was inoculated with a six-strain cocktail of acid-adapted Escherichia coli 0157:H7 at a level of 1x10{sup 7} CFU/g. Following chlorination at 200 {mu}g/ml, the lettuce was irradiated at 0.15, 0.38, or 0.55 kGy using a {sup 60}Co source. Survival of E. coli 0157:H7, aerobic mesophiles and yeast and molds were measured over a period of 10 days. For quality analysis, chlorinated lettuce was subjected to irradiation at 0.33 and 0.53 kGy and stored at 1.0 deg. C, 4.0 deg. C or 7.0 deg. C. Changes in texture and color were determined by instrumental means and changes in flavor, odor, and visual quality were determined by sensory testing. Chlorination plus irradiation at 0.55 kGy produced a 5.4-log reduction in E. coli 0157:H7 levels. Chlorination alone reduced the E. coli 0157:H7 counts by 1-2 logs. Irradiation at 0.55 kGy was also effective in reducing standard plate counts and yeast and mold counts. Irradiation at this level did not cause softening of lettuce and sensory attributes were not adversely affected. In general, appearance and flavor were affected more by the length of storage than by temperature conditions. The 5+log reduction in E. coli counts and lack of adverse effects on sensory attributes indicate that low-dose irradiation can improve the safety and shelf-life of fresh-cut iceberg lettuce for retail sale or food service.

Reduction of Escherichia coli 0157:H7 in shredded iceberg lettuce by chlorination and gamma irradiation

International Nuclear Information System (INIS)

Foley, D.M.; Dufour, A.; Rodriguez, L.; Caporaso, F.; Prakash, A.

2002-01-01

Lettuce was inoculated with a six-strain cocktail of acid-adapted Escherichia coli 0157:H7 at a level of 1x10 7 CFU/g. Following chlorination at 200 μg/ml, the lettuce was irradiated at 0.15, 0.38, or 0.55 kGy using a 60 Co source. Survival of E. coli 0157:H7, aerobic mesophiles and yeast and molds were measured over a period of 10 days. For quality analysis, chlorinated lettuce was subjected to irradiation at 0.33 and 0.53 kGy and stored at 1.0 deg. C, 4.0 deg. C or 7.0 deg. C. Changes in texture and color were determined by instrumental means and changes in flavor, odor, and visual quality were determined by sensory testing. Chlorination plus irradiation at 0.55 kGy produced a 5.4-log reduction in E. coli 0157:H7 levels. Chlorination alone reduced the E. coli 0157:H7 counts by 1-2 logs. Irradiation at 0.55 kGy was also effective in reducing standard plate counts and yeast and mold counts. Irradiation at this level did not cause softening of lettuce and sensory attributes were not adversely affected. In general, appearance and flavor were affected more by the length of storage than by temperature conditions. The 5+log reduction in E. coli counts and lack of adverse effects on sensory attributes indicate that low-dose irradiation can improve the safety and shelf-life of fresh-cut iceberg lettuce for retail sale or food service

MraZ from Escherichia coli: cloning, purification, crystallization and preliminary X-ray analysis

Energy Technology Data Exchange (ETDEWEB)

Adams, Melanie A.; Udell, Christian M.; Pal, Gour Pada; Jia, Zongchao, E-mail: jia@post.queensu.ca [Department of Biochemistry, Queen’s University, Kingston, Ontario K7L 3N6 (Canada)

2005-04-01

The crystallization and preliminary X-ray diffraction analysis of MraZ, formerly known as hypothetical protein YabB, from Escherichia coli K-12 is presented. The MraZ family of proteins, also referred to as the UPF0040 family, are highly conserved in bacteria and are thought to play a role in cell-wall biosynthesis and cell division. The murein region A (mra) gene cluster encodes MraZ proteins along with a number of other proteins involved in this complex process. To date, there has been no clear functional assignment provided for MraZ proteins and the structure of a homologue from Mycoplasma pneumoniae, MPN314, failed to suggest a molecular function. The b0081 gene from Escherichia coli that encodes the MraZ protein was cloned and the protein was overexpressed, purified and crystallized. This data is presented along with evidence that the E. coli homologue exists in a different oligomeric state to the MPN314 protein.

MraZ from Escherichia coli: cloning, purification, crystallization and preliminary X-ray analysis

International Nuclear Information System (INIS)

Adams, Melanie A.; Udell, Christian M.; Pal, Gour Pada; Jia, Zongchao

2005-01-01

The crystallization and preliminary X-ray diffraction analysis of MraZ, formerly known as hypothetical protein YabB, from Escherichia coli K-12 is presented. The MraZ family of proteins, also referred to as the UPF0040 family, are highly conserved in bacteria and are thought to play a role in cell-wall biosynthesis and cell division. The murein region A (mra) gene cluster encodes MraZ proteins along with a number of other proteins involved in this complex process. To date, there has been no clear functional assignment provided for MraZ proteins and the structure of a homologue from Mycoplasma pneumoniae, MPN314, failed to suggest a molecular function. The b0081 gene from Escherichia coli that encodes the MraZ protein was cloned and the protein was overexpressed, purified and crystallized. This data is presented along with evidence that the E. coli homologue exists in a different oligomeric state to the MPN314 protein

Strategies for Protein Overproduction in Escherichia coli.

Science.gov (United States)

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…

Trends in Expanded-Spectrum Cephalosporin-Resistant Escherichia coli and Klebsiella pneumoniae among Dutch Clinical Isolates, from 2008 to 2012

NARCIS (Netherlands)

van der Steen, Matthijs; Leenstra, Tjalling; Kluytmans, Jan A J W; van der Bij, Akke K

2015-01-01

We investigated time trends in extended-spectrum cephalosporin-resistant Escherichia coli and Klebsiella pneumoniae isolates from different patient settings in The Netherlands from 2008-2012. E. coli and K. pneumoniae isolates from blood and urine samples of patients > = 18 years were selected from

Cancerous patients and outbreak of Escherichia coli: an important issue in oncology

OpenAIRE

Joob, Beuy; Wiwanitkit, Viroj

2014-01-01

The widespread of the Escherichia coli outbreak in Europe becomes an important public concern at global level. The infection can be serious and might result in death. The retrospective literature review on this specific topic is performed. In this specific brief article, the author presented and discussed on the problem of Escherichia coli infection in the cancerous patients. This is an actual important issue in medical oncology for the scenario of Escherichia coli epidemic.

Fermentation of sweet whey by recombinant Escherichia coli K011 Fermentação de soro de leite por Escherichia coli KO11 recombinante

Directory of Open Access Journals (Sweden)

Amarildo Ricardo Leite

2000-09-01

Full Text Available The production of ethanol from sweet whey using the recombinant Escherichia coli KO11, in batch fermentation, was tested. The maximum ethanol yield was reached after 96h, representing only 38% of the theoretical yield. The supplementation of whey with components of LB broth increased the maximum yield to 96% in 72h. The addition of 0.5% yeast extract to whey resulted in maximum yield of 74% at 36h and it increased to over 100% when yeast extract and trace metals solution (Fe++, Mn++ and Zn++ were added.A produção de etanol a partir de soro de leite empregando a cepa Escherichia coli KO11 recombinante, em fermentação de batelada, foi testada. O rendimento máximo de etanol foi obtido em 96h, representando apenas 38% do rendimento teórico. A suplementação do soro com os componentes do caldo LB aumentou o rendimento para 96% em 72h. A adição de 0,5% de extrato de levedura ao soro resultou em um rendimento máximo de 74% em 36h que aumentou para acima de 100% quando se adicionou extrato de levedura e uma solução de metais traço (Fe++, Mn++ e Zn++.

Infectious endocarditis caused by Escherichia coli

DEFF Research Database (Denmark)

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

2011-01-01

Although Escherichia coli is among the most common causes of Gram-negative bacteraemia, infectious endocarditis (IE) due to this pathogen is rare. A 67-y-old male without a previous medical history presented with a new mitral regurgitation murmur and persisting E. coli bacteraemia in spite of broad......-spectrum intravenous antibiotics. Transthoracic and transoesophageal echocardiography revealed a severe mitral endocarditis. E. coli DNA was identified from the mitral valve and the vegetation, and no other pathogen was found. The case was further complicated by spondylodiscitis and bilateral endophthalmitis. Extra...

Translational coupling in Escherichia coli of a heterologous Bacillus subtilis-Escherichia coli gene fusion.

OpenAIRE

Zaghloul, T I; Doi, R H

1986-01-01

The efficient expression in Escherichia coli of the Tn9-derived chloramphenicol acetyltransferase (EC 2.3.1.28) gene fused distal to the promoter and N terminus of the Bacillus subtilis aprA gene was dependent on the initiation of translation from the ribosome-binding site in the aprA gene.

The Escherichia coli transcriptome linked to growth fitness

Directory of Open Access Journals (Sweden)

Bei-Wen Ying

2016-03-01

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

Antibiofilm Effects of Lactobacilli against Ciprofloxacin-Resistant Uropathogenic Escherichia coli strains in Pasteurized Milk

Directory of Open Access Journals (Sweden)

Mahsa Yeganeh

2017-11-01

Full Text Available  Background and Objective: Uropathogenic Escherichia coli-induced urinary tract infections are the most common uropathogenic Escherichia coli etiological agent. In addition, most of biofilms created by these bacteria can be regarded as a serious problem in the food industry. Foodborne diseases have always been considered an emerging public health concern throughout the world. Many outbreaks have been found to be associated with biofilms. Thus, the aim of the present study is to investigate the anti-adhesive effects of lactic acid bacteria against strains of Ciprofloxacin-Resistant Uropathogenic Escherichia coli using microbial techniques in pasteurized milk.Material and Methods: In this study, strains of Lactobacillus plantarum, Lactobacillus casei and Lactobacillus acidophilus were provided from Pasteur Institute of Iran. Twenty strains of Uropathogenic Escherichia coli-Induced Urinary Tract Infections were isolated from patients with urinary tract infection in Shahid Labbafinejad hospital of Iran. Eight strains with ability of biofilm formation were selected for microbial tests. All of these eight strains were resistant to ciprofloxacin. Disk diffusion method was used to assess the susceptibility of all isolates to the ten common antibiotics. Eight samples of Uropathogenic Escherichia coli were inoculated in pasteurized milk. The microtitre plate 100 method was used to detect anti-adhesive activity of lactobacilli supernatant.Results and Conclusion: Results showed that the eight human isolates were resistant to antibiotics. Isolate of number 4 was the most susceptible strains to antibiofilm effects of lactobacilli in the pasteurized milk. The anti-adhesive effects of lactobacilli on Uropathogenic were confirmed in all microbial tests. In this study, Lactobacillus plantarum revealed the highest inhibitory activity against Uropathogenic Escherichia coli 4 strain with inhibition zones of 42 mm. This strain was reported as a proper probiotic

The propagation of Escherichia Coli and of conservative tracers. A comparison

International Nuclear Information System (INIS)

Alexander, I.; Seiler, K.P.

1982-01-01

The propagation of Escherichia Coli (ATCC 11229, Gelsenkirchen) is compared with that of conservative tracers in groundwater. The experiments were performed with injection quantities of 10 7 , 10 8 , 10 10 and 10 11 of Escherichia Coli. Both, bacteria and conservative tracers pass their maximum at the same instant in the observation gauges. With injection quantities of more than 10 8 , the propagation of the Escherichia Coli sets in at the same time as it begins with the dyes. When the quantities range below 10 8 , the propagation begins after that of conservative tracers, because Coli bacteria were measured with a lower degree of detecting sensitivity than the tracers. With Coli injection quantities ranging above 10 10 , an increased filtering of these bacteria can be observed. Coli bacteria propagate more laterally than conservative tracers, however it could not be proved that this lateral propagation depends on the bacteria concentration. (orig.) [de

Affinity Isolation and I-DIRT Mass Spectrometric Analysis of the Escherichia coli O157:H7 Sakai RNA Polymerase Complex▿

Science.gov (United States)

Lee, David J.; Busby, Stephen J. W.; Westblade, Lars F.; Chait, Brian T.

2008-01-01

Bacteria contain a single multisubunit RNA polymerase that is responsible for the synthesis of all RNA. Previous studies of the Escherichia coli K-12 laboratory strain identified a group of effector proteins that interact directly with RNA polymerase to modulate the efficiency of transcription initiation, elongation, or termination. Here we used a rapid affinity isolation technique to isolate RNA polymerase from the pathogenic Escherichia coli strain O157:H7 Sakai. We analyzed the RNA polymerase enzyme complex using mass spectrometry and identified associated proteins. Although E. coli O157:H7 Sakai contains more than 1,600 genes not present in the K-12 strain, many of which are predicted to be involved in transcription regulation, all of the identified proteins in this study were encoded on the “core” E. coli genome. PMID:18083804

Alignment of Escherichia coli K12 DNA sequences to a genomic restriction map.

Science.gov (United States)

Rudd, K E; Miller, W; Ostell, J; Benson, D A

1990-01-25

We use the extensive published information describing the genome of Escherichia coli and new restriction map alignment software to align DNA sequence, genetic, and physical maps. Restriction map alignment software is used which considers restriction maps as strings analogous to DNA or protein sequences except that two values, enzyme name and DNA base address, are associated with each position on the string. The resulting alignments reveal a nearly linear relationship between the physical and genetic maps of the E. coli chromosome. Physical map comparisons with the 1976, 1980, and 1983 genetic maps demonstrate a better fit with the more recent maps. The results of these alignments are genomic kilobase coordinates, orientation and rank of the alignment that best fits the genetic data. A statistical measure based on extreme value distribution is applied to the alignments. Additional computer analyses allow us to estimate the accuracy of the published E. coli genomic restriction map, simulate rearrangements of the bacterial chromosome, and search for repetitive DNA. The procedures we used are general enough to be applicable to other genome mapping projects.

Investigations into the design principles in the chemotactic behavior of Escherichia coli.

Science.gov (United States)

Kim, Tae-Hwan; Jung, Sung Hoon; Cho, Kwang-Hyun

2008-01-01

Inspired by the recent studies on the analysis of biased random walk behavior of Escherichia coli[Passino, K.M., 2002. Biomimicry of bacterial foraging for distributed optimization and control. IEEE Control Syst. Mag. 22 (3), 52-67; Passino, K.M., 2005. Biomimicry for Optimization, Control and Automation. Springer-Verlag, pp. 768-798; Liu, Y., Passino, K.M., 2002. Biomimicry of social foraging bacteria for distributed optimization: models, principles, and emergent behaviors. J. Optim. Theory Appl. 115 (3), 603-628], we have developed a model describing the motile behavior of E. coli by specifying some simple rules on the chemotaxis. Based on this model, we have analyzed the role of some key parameters involved in the chemotactic behavior to unravel the underlying design principles. By investigating the target tracking capability of E. coli in a maze through computer simulations, we found that E. coli clusters can be controlled as target trackers in a complex micro-scale-environment. In addition, we have explored the dynamical characteristics of this target tracking mechanism through perturbation of parameters under noisy environments. It turns out that the E. coli chemotaxis mechanism might be designed such that it is sensitive enough to efficiently track the target and also robust enough to overcome environmental noises.

76 FR 20542 - Escherichia coli

Science.gov (United States)

2011-04-13

... beef, Escherichia coli and coliphages were found in chicken, fresh pork, fresh oyster, fresh mushrooms, lettuce, chicken pot pie, biscuit dough, deli loaf, deli roasted turkey, and package roasted chicken... surfaces, and in foods such as ground beef, pork sausage, chicken, oysters, cheese, fresh mushrooms, and...

Epidemiology and clinical manifestations of enteroaggregative Escherichia coli

DEFF Research Database (Denmark)

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

2014-01-01

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

Molecular prophage typing of avian pathogenic Escherichia coli.

Science.gov (United States)

Kwon, Hyuk-Joon; Seong, Won-Jin; Kim, Jae-Hong

2013-03-23

Escherichia coli prophages confer virulence and resistance to physico-chemical, nutritional, and antibiotic stresses on their hosts, and they enhance the evolution of E. coli. Thus, studies on profiles of E. coli prophages are valuable to understand the population structure and evolution of E. coli pathogenicity. Large terminase genes participate in phage genome packaging and are one of the cornerstones for the identification of prophages. Thus, we designed primers to detect 16 types of large terminase genes and analyzed the genomes of 48 E. coli and Shigella reference strains for the prophage markers. We also investigated the distribution of the 16 prophage markers among 92 avian pathogenic E. coli (APEC) strains. APEC strains were classified into 61 prophage types (PPTs). Each strain was different from the reference strains as measured by the PPTs and from the frequency of each prophage marker. Investigation of the distribution of prophage-related serum resistance (bor), toxin (stx1 and cdtI), and T3SS effector (lom, espK, sopE, nleB, and ospG) genes revealed the presence of bor (44.1%), lom (95.5%) and cdtI (9.1%) in APEC strains with related prophages. Therefore, the molecular prophage typing method may be useful to understand population structure and evolution of E. coli pathogenicity, and further studies on the mobility of the prophages and the roles of virulence genes in APEC pathogenicity may be valuable. Copyright © 2012 Elsevier B.V. All rights reserved.

Polyelectrolyte-Functionalized Nanofiber Mats Control the Collection and Inactivation of Escherichia coli

Directory of Open Access Journals (Sweden)

Katrina A. Rieger

2016-04-01

Full Text Available Quantifying the effect that nanofiber mat chemistry and hydrophilicity have on microorganism collection and inactivation is critical in biomedical applications. In this study, the collection and inactivation of Escherichia coli K12 was examined using cellulose nanofiber mats that were surface-functionalized using three polyelectrolytes: poly (acrylic acid (PAA, chitosan (CS, and polydiallyldimethylammonium chloride (pDADMAC. The polyelectrolyte functionalized nanofiber mats retained the cylindrical morphology and average fiber diameter (~0.84 µm of the underlying cellulose nanofibers. X-ray photoelectron spectroscopy (XPS and contact angle measurements confirmed the presence of polycations or polyanions on the surface of the nanofiber mats. Both the control cellulose and pDADMAC-functionalized nanofiber mats exhibited a high collection of E. coli K12, which suggests that mat hydrophilicity may play a larger role than surface charge on cell collection. While the minimum concentration of polycations needed to inhibit E. coli K12 was 800 µg/mL for both CS and pDADMAC, once immobilized, pDADMAC-functionalized nanofiber mats exhibited a higher inactivation of E. coli K12, (~97%. Here, we demonstrate that the collection and inactivation of microorganisms by electrospun cellulose nanofiber mats can be tailored through a facile polyelectrolyte functionalization process.

Polyelectrolyte-Functionalized Nanofiber Mats Control the Collection and Inactivation of Escherichia coli

Science.gov (United States)

Rieger, Katrina A.; Porter, Michael; Schiffman, Jessica D.

2016-01-01

Quantifying the effect that nanofiber mat chemistry and hydrophilicity have on microorganism collection and inactivation is critical in biomedical applications. In this study, the collection and inactivation of Escherichia coli K12 was examined using cellulose nanofiber mats that were surface-functionalized using three polyelectrolytes: poly (acrylic acid) (PAA), chitosan (CS), and polydiallyldimethylammonium chloride (pDADMAC). The polyelectrolyte functionalized nanofiber mats retained the cylindrical morphology and average fiber diameter (~0.84 µm) of the underlying cellulose nanofibers. X-ray photoelectron spectroscopy (XPS) and contact angle measurements confirmed the presence of polycations or polyanions on the surface of the nanofiber mats. Both the control cellulose and pDADMAC-functionalized nanofiber mats exhibited a high collection of E. coli K12, which suggests that mat hydrophilicity may play a larger role than surface charge on cell collection. While the minimum concentration of polycations needed to inhibit E. coli K12 was 800 µg/mL for both CS and pDADMAC, once immobilized, pDADMAC-functionalized nanofiber mats exhibited a higher inactivation of E. coli K12, (~97%). Here, we demonstrate that the collection and inactivation of microorganisms by electrospun cellulose nanofiber mats can be tailored through a facile polyelectrolyte functionalization process. PMID:28773422

Postgenomics Characterization of an Essential Genetic Determinant of Mammary Pathogenic Escherichia coli

Science.gov (United States)

2018-01-01

ABSTRACT Escherichia coli are major bacterial pathogens causing bovine mastitis, a disease of great economic impact on dairy production worldwide. This work aimed to study the virulence determinants of mammary pathogenic E. coli (MPEC). By whole-genome sequencing analysis of 40 MPEC and 22 environmental (“dairy-farm” E. coli [DFEC]) strains, we found that only the fec locus (fecIRABCDE) for ferric dicitrate uptake was present in the core genome of MPEC and that it was absent in DFEC genomes (P mastitis, whereas the fec+ DFEC K71 mutant was able to trigger intramammary inflammation. For the first time, a single molecular locus was shown to be crucial in MPEC pathogenicity. PMID:29615502

Purification and characterization of recombinant protein kinase CK2 from Zea mays expressed in Escherichia coli

DEFF Research Database (Denmark)

Riera, Marta; Pages, Montserrat; Issinger, Olaf Georg

2003-01-01

Recombinant protein kinase subunits rmCK2alpha-1 and rmCK2beta-1 from Zea mays were expressed separately in Escherichia coli and assembled to a fully active tetrameric holoenzyme complex in vitro. The obtained maize holoenzyme was purified to homogeneity, biochemically characterized, and compared...... to CK2 from human. Kinetic measurements of the recombinant maize holoenzyme (rmCK2) revealed k(cat) values for ATP and GTP of 4 and 2s(-1), respectively; whereas the recombinant maize catalytic subunit showed almost equal values for ATP and GTP, i.e., ca. 0.8s(-1). A comparison of the k(cat)/K(m) ratio...

Sex-related effects of nutritional supplementation of Escherichia coli: relevance to eating disorders.

Science.gov (United States)

Tennoune, Naouel; Legrand, Romain; Ouelaa, Wassila; Breton, Jonathan; Lucas, Nicolas; Bole-Feysot, Christine; do Rego, Jean-Claude; Déchelotte, Pierre; Fetissov, Sergueï O

2015-03-01

The biological background of sex-related differences in the development of eating disorders (EDs) is unknown. Recent data showed that gut bacteria Escherichia coli induce autoantibodies against anorexigenic α-melanocyte-stimulating hormone (α-MSH) associated with psychopathology in ED. The aim of this study was to compare the effects of E. coli on feeding and autoantibodies against α-MSH and adrenocorticotropic hormone (ACTH), between female and male rats. Commensal E. coli K12 were given in a culture medium daily to adult Wistar rats by intragastric gavage over a 3-wk period; control rats received culture medium only. Before gavage, E. coli K12 DNA was detected in feces of female but not male rats. E. coli provision was accompanied by an increase in body weight gain in females, but a decrease in body weight gain and food intake in males. Independent of E. coli treatment, plasma levels of anti-α-MSH and ACTH immunoglobulin (Ig)G were higher in female than male rats. Females responded to E. coli by increasing α-MSH IgG levels and affinity, but males by increasing α-MSH IgM levels. Affinity of IgG for ACTH was increased in both E. coli-treated females and males, although with different kinetics. IgG from females stimulated more efficiently α-MSH-induced cyclic adenosine monophosphate production by melanocortin 4 receptor-expressing cells compared with IgG from males. Sex-related response to how E. coli affects feeding and anti-melanocortin hormone antibody production may depend on the presence of these bacteria in the gut before E. coli supplementation. These data suggest that sex-related presence of certain gut bacteria may represent a risk factor for ED development. Copyright © 2015 Elsevier Inc. All rights reserved.

Photoreactivable sector of lethal damage in ultraviolet-irradiated Escherichia coli cells

International Nuclear Information System (INIS)

Balgavy, P.

1976-01-01

The photoreactivable sector of lethal damage in Escherichia coli Bsub(s-1), Escherichia coli B/r Hcr - and Escherichia coli B/r Hcr + cells after ultraviolet irradiation at 254 nm is 0.823 +- 0.004, 0.70 +- 0.01 and 0.53 +- 0.06, respectively, at 99% confidence limits. For the low values of the photoreactivable sector in the B/r Hcr - and B/r Hcr + strains are likely to be responsible dark repair processes which eliminate lethal damage, brought about by pyrimidine dimers, preferably in comparison with lethal damage caused by photoproducts of another type. (author)

Escherichia coli as a probiotic?

NARCIS (Netherlands)

Jansen, GJ; Wildeboer-Veloo, ACM; van der Waaij, D; Degener, JE

1998-01-01

The influence of oral treatment with a suspension of non-pathogenic Escherichia coli cells (commercially available as: Symbioflor II(R)) on the morphological composition of the gut microflora and on the systemic humoral immune response (the IgG-, IgA- and IgM-isotype) against the bacterial cells in

PENGARUH PERASAN DAUN BELIMBING WULUH (Averrhoa bilimbi TERHADAP PERTUMBUHAN BAKTERI Escherichia coli PATOGEN

Directory of Open Access Journals (Sweden)

Fitrotin Azizah

2017-12-01

abstract  (Averrhoa bilimbi is one of the plants that can be used as an antibacterial, good flowers, stems, leaves and stems have benefits and efficacy. Chemical constituents of the leaves starfruit are tannins, flavonoids, saponins. The active ingredient in the leaves starfruit is tannin. Escherichia coli is a bacterium that causes diarrhea. From the above discussion, the authors raised the theme of Influence starfruit juice of the leaves on the growth of pathogenic E. coli bacteria. Formulation of the problem researchers is whether there is influence starfruit juice of the leaves on the growth of Escherichia coli pathogens. This study aims to determine the concentration that could inhibit and kill Esherichia coli Escherichia coli. This research is experimental. The sample used is leaf green starfruit not so young in a fresh state taken in the area around the boarding author Sutorejo 11B stay. In this study, the sample size for each treatment as much as 3 100%, 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, 10% and C (control. Independent variables are starfruit juice of the leaves, while the dependent variable growth of Escherichia coli. When the study carried out in January and July 2012. Data on the effect of starfruit juice of the leaves on the growth of Escherichia coli tested by laboratory examination and data collection techniques using Chi-Square 0:05. Based on the results it appears that at a concentration of 100% and 90% were able to kill the bacteria Escherichia coli, whereas the inhibitory power ranging from a concentration of 80%, 70%, 60%, 50%, 40%, 30%, 20%, 10%. From Chi-Square test was obtained λ2 count Escherichia coli pathogenic bacteria. Keyword : Leaves starfruit, E. Coli

D-Allose catabolism of Escherichia coli

DEFF Research Database (Denmark)

Poulsen, Tim S.; Chang, Ying-Ying; Hove-Jensen, Bjarne

1999-01-01

Genes involved in allose utilization of Escherichia coli K-12 are organized in at least two operons, alsRBACE and alsI, located next to each other on the chromosome but divergently transcribed. Mutants defective in alsI (allose 6-phosphate isomerase gene) and alsE (allulose 6-phosphate epimerase...... gene) were Als-. Transcription of the two allose operons, measured as β-galactosidase activity specified by alsI-lacZ+ or alsE-lacZ+ operon fusions, was induced by allose. Ribose also caused derepression of expression of the regulon under conditions in which ribose phosphate catabolism was impaired....

A novel, simple, high-throughput method for isolation of genome-wide transposon insertion mutants of Escherichia coli K-12.

Science.gov (United States)

Miki, Takeyoshi; Yamamoto, Yoshihiro; Matsuda, Hideo

2008-01-01

We developed a novel, simple, high-throughput method for isolation of genome-wide transposon insertion mutants of Escherichia coli K-12. The basic idea of the method is to randomly disrupt the genes on the DNA fragments cloned on the Kohara library by inserting a mini-transposon first, and then transfer the disrupted genes from the lambda vector to the E. coli chromosome by homologous recombination. Using this method, we constructed a set of 8402 Km(r) cis-diploid mutants harboring a mini-Tn10 insertion mutation and the corresponding wild-type gene on a chromosome, as well as a set of 6954 haploid mutants derived from the cis-diploid mutants. The major advantage of the strategy used is that the indispensable genes or sites for growth can be identified. Preliminary results suggest that 415 open reading frames are indispensable for growth in E. coli cells. A total of 6404 haploid mutants were deposited to Genetic Strains Research Center, National Institute of Genetics, Japan (Chapter 26) and are available for public distribution upon request (http://shigen.lab.nig.ac.jp/ecoli/strain/nbrp/resource.jsp).

Fosfomycin Resistance in Escherichia coli, Pennsylvania, USA.

Science.gov (United States)

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

2015-11-01

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

Neonatal infections caused by Escherichia coli at the National ...

African Journals Online (AJOL)

Background: Escherichia coli (E.coli) has been implicated as a common cause of both early and late onset neonatal infections. The emergence of different strains of E.coli that are multiply resistant to commonly used antibiotics has made continuous antibiotics surveillance relevant. Knowledge about common infections ...

neonatal infections caused by escherichia coli at the national

African Journals Online (AJOL)

boaz

Background: Escherichia coli (E.coli) has been implicated as a common cause of both early and late onset neonatal infections. The emergence of different strains of E.coli that are multiply resistant to commonly used antibiotics has made continuous antibiotics surveillance relevant. Knowledge about common infections ...

Deciphering Fur transcriptional regulatory network highlights its complex role beyond iron metabolism in Escherichia coli

DEFF Research Database (Denmark)

Seo, Sang Woo; Kim, Donghyuk; Latif, Haythem

2014-01-01

The ferric uptake regulator (Fur) plays a critical role in the transcriptional regulation of iron metabolism. However, the full regulatory potential of Fur remains undefined. Here we comprehensively reconstruct the Fur transcriptional regulatory network in Escherichia coli K-12 MG1655 in response...

The effects of combined treatment of irradiation and heat on bacteria escherichia coli and sarcina lutea in dry condition

International Nuclear Information System (INIS)

Nikham; Hilmy, Nazly

1987-01-01

The effects of combination treatment of irradiation and heat on bacteria escherichia coli and sarcina lutea in dry condition. Investigation on the effects of combined irradiation + heat and heat + irradiation treatments have been carried out i.e. at the doses of 0; 1.0; 1.5; and 2.0 kGy with heating at 50 0 C for 10; 20; and 30 minutes on escherichia coli B/r, escherichia coli from sludge and sarcine lutea. Samples of bacteria were prepared in dry condition by using sterile fine sand as carrier. Irradiation was done in aerobic condition with RH 90% and the time range between irradiation and heating was not more than 2 hours. The results showed that the D 10 value did not give significant difference between the combined irradiation + heat, and heat + irradiation treatments for the 3 species of bacteria, compared to irradiation only (p 0.05). Doses of 1.0 and 1.5 kGy combined with heating at 50 0 C for 10 and 20 minutes gave better results compared to irradiation only. 17 refs

Purification, crystallization and preliminary X-ray analysis of isocitrate dehydrogenase kinase/phosphatase from Escherichia coli

International Nuclear Information System (INIS)

Zheng, Jimin; Lee, Daniel C.; Jia, Zongchao

2009-01-01

Isocitrate dehydrogenase kinase/phosphatase has been crystallized in three different crystal forms. Data were collected from each crystal form for structure determination. The Escherichia coli aceK gene encodes isocitrate dehydrogenase kinase/phosphatase (EC 2.7.11.5), a bifunctional protein that phosphorylates and dephosphorylates isocitrate dehydrogenase (IDH), resulting in its inactivation and activation, respectively. This reversible (de)phosphorylation directs isocitrate, an intermediate of the citric acid cycle, to either go through the full cycle or to enter the glyoxylate bypass. In the present study, the AceK protein from E. coli has been purified and crystallized. Three crystal forms were obtained from very similar crystallization conditions. The crystals belong to space groups P4 1 2 1 2, P3 2 21 and P2 1 2 1 2 1 and diffracted X-rays to resolutions of 2.9, 3.0 and 2.7 Å, respectively

the occurrence of escherichia coli o157:h7 in market and abattoir

African Journals Online (AJOL)

user

Escherichia coli O157:H7 is a newly emerging pathogen frequently associated with the consumption of foods of ... KEY WORDS: E. coli O157:H7, Pathogen, Abattoir, Market, and Infections ..... pathogen. Escherichia coli O157:H7 as a model of.

Characterization of new radiation-sensitive mutant, Escherichia coli K-12 radC102

International Nuclear Information System (INIS)

Felzenszwalb, I.; Sargentini, N.J.; Smith, K.C.

1984-01-01

A new radiation-sensitive mutant, radC, has been isolated. The radC gene is located at 81.0 min on the Escherichia coli K-12 linkage map. The radC mutation sensitized cells to uv radiation, but unlike most DNA repair mutations, sensitization to X rays was observed only for rich medium-grown cells. For cells grown in rich medium, the radC mutant was normal for γ radiation mutagenesis, but showed less uv-radiation mutagenesis than the wild-type strain; it showed normal amount of X- and uv-radiation-induced DNA degradation, and it wasapprox. =60% deficient in recombination ability. The radC strain was normal for host cell reactivation of γ and uv-irradiated bacteriophage the radC mutation did not sensitize a recA strain, but did sensitize a radA and a polA strain to X and uv radiation and a uvrA strain to uv radiation. Therefore, it is suggested that the radC gene product plays a role in the growth medium-dependent, recA gene-dependent repair of DNA single-strand breaks after X irradiation, and in postreplication repair after uv irradiation

ESCHERICHIA COLI AND STAPHYLOCOCCUS AUREUS

African Journals Online (AJOL)

DR. AMINU

ABSTRACT. The bio-effects of the ethanol extracts from the leaf and stem of Momordica charantia were studied with the view to ascertain the medical usefulness ascribed to the plant by the locals. The plant parts, stem and leaf, revealed remarkable activity against Escherichia coli and Staphlococcus aureus. The leaves ...

Conjugal Pairing in Escherichia Coli

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 13; Issue 8. Conjugal Pairing in Escherichia Coli. Joshua Lederberg. Classics Volume 13 Issue 8 August 2008 pp 793-794. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/013/08/0793-0794 ...

Cefoxitin resistance mediated by loss of a porin in clinical strains of Klebsiella pneumoniae and Escherichia coli

Directory of Open Access Journals (Sweden)

Ananthan S

2005-01-01

Full Text Available PURPOSE: Porins are outer membrane protein (OMP that form water filled channels that permit the diffusion of small hydrophilic solutes like -lactam antibiotics across the outer membrane. Two major porins that facilitate diffusion of antimicrobials have been described in Klebsiella spp. and Escherichia coli. The present study was carried out to examine the role of porins among Extended Spectrum -Lactamase (ESBL and AmpC -Lactamase positive strains of Klebsiella spp. and E.coli. METHODS: Preparation of OMP from phenotypically characterized clinical isolates K.pneumoniae and E.coli and the separation of the proteins by sodium dodecyl sulfate - polyacrylamide gel electrophoresis were performed as per a previously described procedure. RESULTS: OMP analysis revealed that cefoxitin and ceftazidime resistance was mediated by loss of a porin Omp K35 in the isolates of K.pneumoniae and E.coli. CONCLUSIONS: Loss of porin mediated resistance mechanism against cefoxitin was observed among the multidrug resistant K.pneumoniae and E.coli.

The Escherichia coli K-12 gntP gene allows E. coli F-18 to occupy a distinct nutritional niche in the streptomycin-treated mouse large intestine

DEFF Research Database (Denmark)

Sweeney, N.J.; Klemm, Per; McCormick, Beth A.

1996-01-01

Escherichia coli F-18 is a human fecal isolate that makes type 1 fimbriae, encoded by the fim gene cluster, and is an excellent colonizer of the streptomycin-treated mouse intestine. E. coli F-18 fimA::tet, lacking type 1 fimbriae, was constructed by bacteriophage P1 transduction of the fim regio...

Increased multi-drug resistant Escherichia coli from hospitals in ...

African Journals Online (AJOL)

Background: Multidrug-resistant Escherichia coli (MDR E. coli) has become a major public health concern in Sudan and many countries, causing failure in treatment with consequent huge health burden. Objectives: To determine the prevalence and susceptibility of MDR E. coli isolated from patients in hospitals at Khartoum ...

Experimental electromagnetic effects on the model organism Escherichia coli and the bacteriophage T4

Science.gov (United States)

Lisiewski, Darlene Mildred

This experimentally-based work was designed to answer the research question as to whether the phenomenon of nuclear magnetic resonance (NMR) can produce observable effects upon the bacterial virus activity of T4, with such activity demonstrated through the infection of its host bacterium Escherichia coli. The biological samples were placed for three hours within a coil antenna assembly propagating oscillating fields of radio frequency electromagnetic energy generated at the frequency of 5.6 MHz, and set at right angles within a magnetic field of 1450 gauss (recognizing such conditions are not set for the maximum effective resonance for hydrogen nuclei). The laboratory technique of plaque formation was the basis upon which the statistically tested data were compiled. Exposure of the bacterium alone exhibited an increase in viral activity over the control group (40--68% higher numbers of plaque formation), while exposure of T4 alone saw a decrease (approximately 23%) in infection rates. Depending on the protocol, placement of both T4 and E. coli into the coil assembly saw a decrease of either approximately 50% or 42% in infection rates. Future research must address identification of the effects being observed.

Crystallization and preliminary X-ray diffraction analysis of ybfF, a new esterase from Escherichia coli K12

Energy Technology Data Exchange (ETDEWEB)

Park, Suk-Youl; Lee, Sang-Hak; Lee, Jieun; Jung, Che-Hun; Kim, Jeong-Sun, E-mail: jsunkim@chonnam.ac.kr [Department of Chemistry and Institute of Basic Sciences, Chonnam National University, Gwangju 500-757 (Korea, Republic of)

2007-12-01

The crystallization of ybfF, a new esterase from E. coli, and the collection of diffraction data to 1.1 Å resolution are reported. The product of the recently discovered ybfF gene, which belongs to the esterase family, does not show high sequence similarity to other esterases. To provide the molecular background to the enzymatic mechanism of the ybfF esterase, the ybfF protein from Escherichia coli K12 (Ec-ybfF) was cloned, expressed and purified. The Ec-ybfF protein was crystallized from 60% Tacsimate and 0.1 M bis-Tris propane buffer pH 7.0. Diffraction data were collected to 1.10 Å resolution using synchrotron radiation. The crystal belongs to the orthorhombic space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 66.09, b = 90.71, c = 92.88 Å. With two Ec-ybfF molecules in the asymmetric unit, the crystal volume per unit protein weight is 2.17 Å{sup 3} Da{sup −1}, corresponding to a solvent content of 42%.

Genetic analysis of an Escherichia coli urease locus: evidence of DNA rearrangement.

OpenAIRE

Collins, C M; Falkow, S

1988-01-01

Ureolytic Escherichia coli strains are uncommon clinical isolates. The urease phenotype in a large percentage of these isolates is unstable and lost upon storage. We examined two urease-positive uropathogenic E. coli isolates that give off urease-negative segregants and determined that the urease phenotype was chromosomally encoded. The urease phenotype was cloned from E. coli 1021 and found to be encoded on a 9.4-kilobase HindIII restriction fragment. Transposon mutagenesis indicated that at...

The in vitro synthesis of {beta}-galactosidase induced in a subcellular structure of Escherichia coli (1961); Synthese in vitro de {beta}-galactosidase induite dans une structure subcellulaire d'Escherichia coli (1961)

Energy Technology Data Exchange (ETDEWEB)

Nisman, B; Kayser, A; Demailly, J; Genin, C [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1961-07-01

Isopropyl-thio-galactoside (IPTG), an inducer of 3-galactosidase, makes it possible to synthesise this enzyme in vitro with the subcellular structure (P{sub 1}). The enzyme is isolated from the bacteria Escherichia coli K 12 which are inductive but not induced. The incorporation of radioactive amino-acids, which is stimulated by the presence of an inducer, was studied during the course of the enzyme synthesis. Saccharose suppresses the induction of {beta}-galactosidase. The presence of a specific inhibitor in the structure studied is considered. (authors) [French] L'isopropylthiogalactoside (IPTG), inducteur de la 3-galactosidase, permet la synthese in vitro de cette enzyme dans la structure subcellulaire (P{sub 1}) isolee a partir des bacteries d'Escherichia coli K 12, inductibles mais non induites. L'incorporation d'acides amines radioactifs, stimulee par la presence d'inducteur, a ete etudiee au cours de la synthese de l'enzyme. Le saccharose supprime l'induction de la 3-galactosidase. La presence du represseur specifique dans la structure etudiee est consideree. (auteurs)

Emergence and mechanism of carbapenem-resistant Escherichia coli in Henan, China, 2014

Directory of Open Access Journals (Sweden)

Wen-juan Liang

2018-05-01

Full Text Available The emergence and dissemination of carbapenem-resistant Escherichia coli (E. coli strains is a main risk for global public health, but little is known of carbapenemase producing E. coli in Henan, China. The study was undertaken to investigate the prevalence and mechanism of carbapenem-resistant E. coli strains in a hospital in Xinxiang, Henan, China, 2014. A total of 5 carbapenemase-producing E. coli strains were screened from 1014 isolates. We found that they were all resistant to meropenem and imipenem. Amikacin showed the best sensitivity, with gentamicin coming up next. The positive rate of blaNDM was 80% (4/5. The sequencing results showed that two isolates belonged to blaNDM-1 whereas other 2 isolates carried the blaNDM-5. Other carbapenemase genes including blaIMP, blaVIM, blaKPC and blaOXA-48 were not detected. The blaCTX-M-15, blaTEM-1, sul2, aad, and aac(6”–Ib–cr were also detected. MLST analysis showed that NDM-producing E. coli were sporadic. Conjugation test indicated blaNDM could be transferred. In conclusion, the blaNDM was the principal resistance mechanism of carbapenem-resistant E. coli in the hospital, Henan, China. Keywords: blaNDM, Carbapenem-resistant, Escherichia coli

Draft genome sequences of six neonatal meningitis-causing escherichia coli isolates (SP-4, SP-5, SP-13, SP-16, SP-46, and SP-65)

Science.gov (United States)

Neonatal meningitis Escherichia coli isolates (SP-4, SP-5, SP-13, SP-16, SP-46, and SP-65) were recovered from infants in the Netherlands from 1989 to 1997. Here, we report the draft genome sequences for these six E. coli isolates, which are currently being used to validate food safety processing te...

Research on killing Escherichia Coli by reactive oxygen species based on strong ionization discharging plasma

International Nuclear Information System (INIS)

Li, Y J; Tian, Y P; Zhang, Z T; Li, R H; Cai, L J; Gao, J Y

2013-01-01

Reactive oxygen species solution produced by strong ionization discharging plasma was used to kill Escherichia coli by spraying. Several effect factors such as pH value, solution temperature, spraying time and exposure time were observed in this study, and their effects on killing rate of Escherichia coli were discussed and analysed. Results show that the treating efficiency of ROS solution for Escherichia coli is higher in alkaline solution than that in acid solution. The killing rate of Escherichia coli increases while the spraying time and exposure time are longer and the temperature is lower. The effects of different factors on killing rate of Escherichia coli are as follows: spraying time > pH value > exposure time > solution temperature.

Effect of different butyrate supplementations on growth and health of weaning pigs challenged or not with E. coli K88

Directory of Open Access Journals (Sweden)

Paolo Trevisi

2010-01-01

Full Text Available In a full factorial design (4 diets X challenge, Yes/No, 72 weaning pigs were assigned to one of the diets: Control; experimental diets, obtained with the addition of 2 g/kg free sodium butyrate (fNaB, or 0.6 g/kg fat-protected sodium butyrate (pNaB, or 2 g/kg INVE-NutriAd commercial mixture (Mix, based on 75 g/kg protected butyrate. Oral challenge with Escherichia coli K88 was done on 2/3 of pigs on d 7. Pigs were slaughtered on d 13. The mortality in challenged pigs, tended to be higher in control group (50.0% than in the three supplemented groups (23.5%. Growth tended to be increased averagely by the supplements (p=0.100 after the challenge, that also significantly reduced growth. In general the diet did not affect the fecal shedding of Escherichia coli and Lactobacilli, the K88-specific IgA activity in blood, the morphology of oxyntic mucosa and the expression of H+/K+-ATPase gene. The supplementations tended to increase villous length of jejunum (p=0.101. On the whole, growth, villous height and surviving rate can be positively affected either when the supplementation is done by free butyrate, by protected butyrate or by the special Inve Nutri-Ad product and these effects are distributed both on pigs infected or not with Escherichia coli K88.

Development of a new fluorescent reporter:operator system: location of AraC regulated genes in Escherichia coli K-12.

Science.gov (United States)

Sellars, Laura E; Bryant, Jack A; Sánchez-Romero, María-Antonia; Sánchez-Morán, Eugenio; Busby, Stephen J W; Lee, David J

2017-08-03

In bacteria, many transcription activator and repressor proteins regulate multiple transcription units that are often distally distributed on the bacterial genome. To investigate the subcellular location of DNA bound proteins in the folded bacterial nucleoid, fluorescent reporters have been developed which can be targeted to specific DNA operator sites. Such Fluorescent Reporter-Operator System (FROS) probes consist of a fluorescent protein fused to a DNA binding protein, which binds to an array of DNA operator sites located within the genome. Here we have developed a new FROS probe using the Escherichia coli MalI transcription factor, fused to mCherry fluorescent protein. We have used this in combination with a LacI repressor::GFP protein based FROS probe to assess the cellular location of commonly regulated transcription units that are distal on the Escherichia coli genome. We developed a new DNA binding fluorescent reporter, consisting of the Escherichia coli MalI protein fused to the mCherry fluorescent protein. This was used in combination with a Lac repressor:green fluorescent protein fusion to examine the spatial positioning and possible co-localisation of target genes, regulated by the Escherichia coli AraC protein. We report that induction of gene expression with arabinose does not result in co-localisation of AraC-regulated transcription units. However, measurable repositioning was observed when gene expression was induced at the AraC-regulated promoter controlling expression of the araFGH genes, located close to the DNA replication terminus on the chromosome. Moreover, in dividing cells, arabinose-induced expression at the araFGH locus enhanced chromosome segregation after replication. Regions of the chromosome regulated by AraC do not colocalise, but transcription events can induce movement of chromosome loci in bacteria and our observations suggest a role for gene expression in chromosome segregation.

flu, a metastable gene controlling surface properties of Escherichia coli.

OpenAIRE

Diderichsen, B

1980-01-01

flu, a gene of Escherichia coli K-12, was discovered and mapped between his and shiA. It is shown that flu is a metastable gene that changes frequently between the flu+ and flu states. flu+ variants give stable homogeneous suspensions, are piliated, and form glossy colonies. flu variants aggregate, fluff and sediment from suspensions, are nonpiliated, and form frizzy colonies. flu+ and flu variants can be isolated from most strains. Implications of these observations are discussed, and it is ...

A tale of tails: Sialidase is key to success in a model of phage therapy against K1-capsulated Escherichia coli

International Nuclear Information System (INIS)

Bull, J.J.; Vimr, E.R.; Molineux, I.J.

2010-01-01

Prior studies treating mice infected with Escherichia coli O18:K1:H7 observed that phages requiring the K1 capsule for infection (K1-dep) were superior to capsule-independent (K1-ind) phages. We show that three K1-ind phages all have low fitness when grown on cells in serum whereas fitnesses of four K1-dep phages were high. The difference is serum-specific, as fitnesses in broth overlapped. Sialidase activity was associated with all K1-dep virions tested but no K1-ind virions, a phenotype supported by sequence analyses. Adding endosialidase to cells infected with K1-ind phage increased fitness in serum by enhancing productive infection after adsorption. We propose that virion sialidase activity is the primary determinant of high fitness on cells grown in serum, and thus in a mammalian host. Although the benefit of sialidase is specific to K1-capsulated bacteria, this study may provide a scientific rationale for selecting phages for therapeutic use in many systemic infections.

Genomic epidemiology of the Escherichia coli O104:H4 outbreaks in Europe, 2011

DEFF Research Database (Denmark)

Grad, Yonatan H; Lipsitch, Marc; Feldgarden, Michael

2012-01-01

The degree to which molecular epidemiology reveals information about the sources and transmission patterns of an outbreak depends on the resolution of the technology used and the samples studied. Isolates of Escherichia coli O104:H4 from the outbreak centered in Germany in May-July 2011, and the ...... that purged diversity in the German isolates, variation in mutation rates in the two E. coli outbreak populations, or uneven distribution of diversity in the seed populations that led to each outbreak....... remarkably little diversity, with only two single nucleotide polymorphisms (SNPs) found in isolates from four individuals. Surprisingly, we found much greater diversity (19 SNPs) in isolates from seven individuals infected in the French outbreak. The German isolates form a clade within the more diverse...... French outbreak strains. Moreover, five isolates derived from a single infected individual from the French outbreak had extremely limited diversity. The striking difference in diversity between the German and French outbreak samples is consistent with several hypotheses, including a bottleneck...

Pharmacokinetics of amoxicillin after oral administration in recently weaned piglets with experimentally induced Escherichia coli subtype O149 : F4 diarrhea

DEFF Research Database (Denmark)

Jensen, G.M.; Lykkesfeldt, J.; Frydendahl, K.

2004-01-01

Objective-To measure the effect of Escherichia coli subtype 0149:F4-induced diarrhea on the pharmacokinetics of orally administered amoxicillin in affected piglets relative to that of uninfected piglets. Animals-22 healthy 4-week-old recently weaned Danish crossbred piglets. Procedure-12 piglets...... were orally inoculated through gastric intubation with 10(9) CFUs of an E coli 0149:F4 strain and responded by developing diarrhea 12 to 16 hours later. Piglets were dosed with amoxicillin trihydrate solution (20 mg/kg) by gastric intubation. A control group of 10 age-matched piglets without signs...... that the concentration of the antimicrobial at the site of infection reflects the systemic concentration, higher doses of amoxicillin in the treatment of piglets with E coli 0149:F4-induced diarrhea may be appropriate....

Phylogenetic analysis of Escherichia coli isolates from healthy and diarrhoeic calves in Mashhad, Iran

Directory of Open Access Journals (Sweden)

M. Barzan

2017-03-01

Full Text Available Escherichia coli is a normal inhabitant of the gastrointestinal tract of vertebrates. Certain Escherichia coli strains have been associated with neonatal diarrhoea in ruminants. These strains can be assigned to one of the four main phylogenetic groups, A, B1, B2 and D. Several studies have shown the rela-tionship between phylogeny and pathogenicity of E. coli, a great deal can be obtained by determining the phylogroup of unknown E. coli strains. In this study, we aimed to evaluate the influence of diar-rhoea on the genetic composition of E. coli populations isolated from calves. A total of 80 Es-cherichia coli isolates were obtained from healthy and diarrhoeic calves. Phylogenetic grouping was done based on the Clermont triplex PCR method using primers targeted at three genetic markers, chuA, yjaA and TspE4.C2. According to our results, phylogenetic group A strains was the most prevalent in both healthy (37.5% and diarrhoeic calves (55%. Group B1 contained 27.5% of isolates in healthy calves, followed by group B2 (17.5%, and group D (7.5%. Also, four isolates from healthy calves were not included in the major phylogenetic groups or subgroups. A total of 14% and 4% of isolates from diarrhoeic calves beloned to phylogroups B2 and D respectively. Although no isolate from diarrhoeic calves was found to belong to group B1, there was no significant difference between healthy and diarrhoeic calves for other phylogroups. There was not a dramatic shift in E. coli phylogroup/subgroup due to occurrence of diarrhoea in calves, except for phylogroup B1 which was higher in healthy calves. This can be due to the difference in secretions of digestive system in diarrhoeic calves which can prevent the conditions for instability of Escherichia coli isolates of phy-logroup B1. The majority of isolates from both healthy and diarrhoeic calves belonged to non-pathogenic phylogentic group A and B1.

ESBL-Producing Escherichia coli

DEFF Research Database (Denmark)

Hertz, Frederik Boetius

Urinary tract infection (UTI) is one the most common bacterial infections and is regularly treated in primary health care. The most common cause of UTI is extraintestinal pathogenic Escherichia coli (ExPEC) already present in the intestinal microflora, often as the dominating strain. Resistance...... in E.coli is increasing and especially isolates producing Extended-Spectrum Beta-Lactamases (ESBL) have been reported worldwide. Treatment of UTI is usually initiated by the general practitioners and a significant proportion of clinical isolates are now resistant to first line antibiotics. The global...... to investigate (i) antibiotics involved in selection of ESBL-producing E.coli, in an experimental mouse model in vivo, (ii) risk factors for UTI with ESBL-producing E.coli and (iii) to describe the phylogenetic composition of E.coli populations with different resistance patterns. We found that different...

Multiple loci affecting photoreactivation in Escherichia coli

International Nuclear Information System (INIS)

Sutherland, B.M.; Hausrath, S.G.

1979-01-01

Sutherland et al. mapped a phr gene in Escherichia coli at 17 min and found that induction of an E. coli stain lysogenic for a lambda phage carrying this gene increased photoreactivating enzyme levels 2,000-fold. Recently, Smith and Youngs and Sancar and Rupert located a phr gene at 15.9 min. We have therefore investigated the properties of photoreactivating enzyme and cellular photoreactivation in cells containing deletions of the gene at 17 min. Cells with this deletion photoreactivated ultraviolet-induced killing at a rate 20% of normal; they also contained approximately 20% of the normal photoreactivating enzyme level. The residual enzyme in these cells was characterized to determine whether the reduced cellular photoreactivation rate and photoreactivating enzyme levels resulted from reduced numbers of normal enzymes or from an altered enzyme. Photoreactivating enzymes from strains carrying a deletion of the region at 17 min has an apparent K/sub m/ about two- to threefold higher than normal enzyme and showed markedly increased heat lability. The gene at 17 min thus contains information determining the function of the E. coli photoreactivating enzyme rather than the quantity of the enzyme. It is proposed that the gene at 17 min be termed phrA and that located at 15.9 min be termed phrB

Multiplex PCR Assay for Identification of Human Diarrheagenic Escherichia coli

OpenAIRE

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

2003-01-01

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

lactamases genes among0 Escherichia coli from patients with ...

African Journals Online (AJOL)

-lactamases (ESBLs) that mediate resistance to b-lactam drugs among Escherichia coli and other uropathogens have been reported worldwide. However, there is little information on the detection of ESBLs genes in E. coli from patients with ...

Fermented soya bean (tempe) extracts reduce adhesion of enterotoxigenic Escherichia coli to intestinal epithelial cells

NARCIS (Netherlands)

Roubos-van den Hil, P.J.; Nout, M.J.R.; Beumer, R.R.; Meulen, van der J.; Zwietering, M.H.

2009-01-01

Aims: This study aimed to investigate the effect of processed soya bean, during the successive stages of tempe fermentation and different fermentation times, on adhesion of enterotoxigenic Escherichia coli (ETEC) K88 to intestinal brush border cells as well as Caco-2 intestinal epithelial cells; and

Antibacterial activity of irradiated and non-irradiated chitosan and chitosan derivatives against Escherichia coli growth

International Nuclear Information System (INIS)

Tg Ahbrizal Farizal Tg Ahmad; Norimah Yusof; Kamarudin Bahari; Kamaruddin Hashim

2006-01-01

Samples of chitosan and four chitosan derivatives [ionic chitosan, chitosan lactate, carboxymethyl chitosan (C) and carboxymethyl chitosan (L)] were studied for their antibacterial activities against Escherichia coli growth. Chitosan and chitosan derivatives were prepared at concentrations 20, 100, 1000, 10000 ppm and 250, 1000, 5000, 10000, 20000 ppm, respectively. Each of the samples was tested before and after irradiation with electron beam at 25 kGy. The turbidity of bacterial growth media was measured periodically at 0, 0.5, 1, 2, 4, 6 and 24 h after inoculation using the optical density method. The results indicated that non- irradiated chitosan inhibited E. coli growth at 20 and 100 ppm. Meanwhile, irradiated chitosan at 100 and 1000 ppm concentration inhibited E. coli growth. Both irradiated and non-irradiated ionic chitosan inhibited E. coli growth at all concentrations used. Chitosan lactate was found to inhibit E. coli at concentration as low as 5000 ppm for both irradiated and non-irradiated samples. E. coli growth was not inhibited by carboxymethyl chitosan (C) and carboxymethyl chitosan (L), before and after irradiation. The findings suggested that chitosan has greater antibacterial activity as compared to the chitosan derivative samples. (Author)

Revisiting the STEC Testing Approach: Using espK and espV to Make Enterohemorrhagic Escherichia coli (EHEC) Detection More Reliable in Beef

OpenAIRE

Delannoy, Sabine; Chaves, Byron D.; Ison, Sarah A.; Webb, Hattie E.; Beutin, Lothar; Delaval, José; Billet, Isabelle; Fach, Patrick

2016-01-01

Current methods for screening Enterohemorrhagic Escherichia coli (EHEC) O157 and non-O157 in beef enrichments typically rely on the molecular detection of stx, eae, and serogroup-specific wzx or wzy gene fragments. As these genetic markers can also be found in some non-EHEC strains, a number of ‘false positive’ results are obtained. Here, we explore the suitability of five novel molecular markers, espK, espV, ureD, Z2098, and CRISPRO26:H11 as candidates for a more accurate screening of EHEC s...

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

OpenAIRE

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

2010-01-01

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

Efficient Extracellular Expression of Phospholipase D in Escherichia Coli with an Optimized Signal Peptide

Science.gov (United States)

Yang, Leyun; Xu, Yu; Chen, Yong; Ying, Hanjie

2018-01-01

New secretion vectors containing the synthetic signal sequence (OmpA’) was constructed for the secretory production of recombinant proteins in Escherichia coli. The E. coli Phospholipase D structural gene (Accession number:NC_018658) fused to various signal sequence were expressed from the Lac promoter in E. coli Rosetta strains by induction with 0.4mM IPTG at 28°C for 48h. SDS-PaGe analysis of expression and subcellular fractions of recombinant constructs revealed the translocation of Phospholipase D (PLD) not only to the medium but also remained in periplasm of E. coli with OmpA’ signal sequence at the N-terminus of PLD. Thus the study on the effects of various surfactants on PLD extracellular production in Escherichia coli in shake flasks revealed that optimal PLD extracellular production could be achieved by adding 0.4% Triton X-100 into the medium. The maximal extracellular PLD production and extracellular enzyme activity were 0.23mg ml-1 and 16U ml-1, respectively. These results demonstrate the possibility of efficient secretory production of recombinant PLD in E. coli should be a potential industrial applications.

Escherichia coli growth modeling using neural network | Shamsudin ...

African Journals Online (AJOL)

technique that has the ability to predict with efficient and good performance. Using NARX, a highly accurate model was developed to predict the growth of Escherichia coli (E. coli) based on pH water parameter. The multiparameter portable sensor and spectrophotometer data were used to build and train the neural network.

Novel sequence types of extended-spectrum and acquired AmpC beta-lactamase producing Escherichia coli and Escherichia clade V isolated from wild mammals.

Science.gov (United States)

Alonso, Carla Andrea; Alcalá, Leticia; Simón, Carmen; Torres, Carmen

2017-08-01

The closer contact with wildlife due to the growing human population and the destruction of natural habitats emphasizes the need of gaining insight into the role of animals as source of antimicrobial resistance. Here, we aim at characterizing the antimicrobial resistance genes and phylogenetic distribution of commensal Escherichia coli from 62 wild mammals. Isolates exhibiting resistance to ≥1 antibiotic were detected in 25.8% of the animals and 6.4% carried an extended-spectrum beta-lactamase (ESBL)/AmpC-producing E. coli. Genetic mechanisms involved in third-generation cephalosporin resistance were as follows: (i) hyperproduction of chromosomal AmpC (hedgehog), (ii) production of acquired CMY-2 β-lactamase (hedgehog), (iii) production of SHV-12 and CTX-M-14 ESBLs (n = 2, mink and roe-deer). ESBL genes were transferable by conjugation, and blaCMY-2 was mobilized by a 95kb IncI1 plasmid. The distribution of the phylogenetic groups in the E. coli collection studied was B1 (44.6%), B2 (24.6%), E (15.4%), A (4.6%) and F (3.1%). Five isolates (7.7%) were cryptic Escherichia clades (clade IV, 4 mice; clade V, 1 mink). ESBL/AmpC-E. coli isolates showed different sequence types (STs): ST1128/B1, ST4564/B1 (new), ST4996/B1 (new) and a non-registered ST. This study contributes to better understand the E. coli population and antimicrobial resistance flow in wildlife and reports new AmpC-E. coli STs and a first described ESBL-producing Escherichia clade V isolate. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Crystallization and preliminary X-ray analysis of Escherichia coli RNase G

International Nuclear Information System (INIS)

Fang, Pengfei; Wang, Jing; Li, Xu; Guo, Min; Xing, Li; Cao, Xu; Zhu, Yi; Gao, Yan; Niu, Liwen; Teng, Maikun

2009-01-01

Full-length E. coli RNase G was overexpressed, purified and crystallized. Diffraction data were collected to a resolution of 3.4 Å. The homologous RNases RNase E and RNase G are widely distributed in bacteria and function in many important physiological processes, including mRNA degradation, rRNA maturation and so on. In this study, the crystallization and preliminary X-ray analysis of RNase G from Escherichia coli is described. Purified recombinant E. coli RNase G, which has 497 amino acids, was crystallized in the cubic space group F432, with unit-cell parameters a = b = c = 219.84 Å. X-ray diffraction data were collected to a resolution of 3.4 Å

Dietary N-Carbamylglutamate Supplementation Boosts Intestinal Mucosal Immunity in Escherichia coli Challenged Piglets.

Directory of Open Access Journals (Sweden)

Fengrui Zhang

Full Text Available N-carbamylglutamate (NCG has been shown to enhance performance in neonatal piglets. However, few studies have demonstrated the effect of NCG on the intestinal mucosal barrier. This study was conducted to determine the effects of dietary NCG supplementation on intestinal mucosal immunity in neonatal piglets after an Escherichia coli (E. coli challenge. New-born piglets (4 d old were assigned randomly to one of four treatments (n = 7, including (I sham challenge, (II sham challenge +50 mg/kg NCG, (III E. coli challenge, and (IV E. coli challenge +50 mg/kg NCG. On d 8, pigs in the E. coli challenge groups (III and IV were orally challenged with 5 mL of E. coli K88 (10(8 CFU/mL, whereas pigs in the sham challenge groups (I and II were orally dosed with an equal volume of water. On d 13, all piglets were sacrificed, and samples were collected and examined. The results show that average daily gain in the E. coli challenged piglets (III and IV was decreased (PE.coli<0.05. However, it tended to be higher in the NCG treated piglets (II and IV. Ileum secretory IgA, as well as IFN-γ, IL-2, IL-4 and IL-10 in ileal homogenates, were increased in E. coli challenged piglets (III and IV. Similarly, ileum SIgA and IL-10 levels, and CD4(+ percentage in NCG treated piglets (II and IV were higher than no-NCG treated piglets (PNCG<0.05. However, the IL-2 level was only decreased in the piglets of E. coli challenge + NCG group (IV compared with E. coli challenge group (III (P<0.05. No change in the IL-2 level of the sham challenged piglets (III was observed. In conclusion, dietary NCG supplementation has some beneficial effects on intestinal mucosal immunity in E. coli challenged piglets, which might be associated with stimulated lymphocyte proliferation and cytokine synthesis. Our findings have an important implication that NCG may be used to reduce diarrhea in neonatal piglets.

Escherichia coli F4 fimbriae specific lama single-domain antibody fragments effectively inhibit bacterial adhesion in vitro but poorly protect against diarrhea

NARCIS (Netherlands)

Harmsen, M.M.; Solt, van C.B.; Hoogendoorn, A.; Zijderveld, van F.G.; Niewold, T.A.; Meulen, van der J.

2005-01-01

Oral administration of polyclonal antibodies directed against enterotoxigenic Escherichia coli (ETEC) F4 fimbriae is used to protect against piglet post-weaning diarrhoea. For cost reasons, we aim to replace these polyclonal antibodies by recombinant llama single-domain antibody fragments (VHHs)

FTIR nanobiosensors for Escherichia coli detection

Directory of Open Access Journals (Sweden)

Stefania Mura

2012-07-01

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

Hemolytic porcine intestinal Escherichia coli without virulence-associated genes typical of intestinal pathogenic E. coli.

Science.gov (United States)

Schierack, Peter; Weinreich, Joerg; Ewers, Christa; Tachu, Babila; Nicholson, Bryon; Barth, Stefanie

2011-12-01

Testing 1,666 fecal or intestinal samples from healthy and diarrheic pigs, we obtained hemolytic Escherichia coli isolates from 593 samples. Focusing on hemolytic E. coli isolates without virulence-associated genes (VAGs) typical for enteropathogens, we found that such isolates carried a broad variety of VAGs typical for extraintestinal pathogenic E. coli.

Characterization of WbiQ: An α1,2-fucosyltransferase from Escherichia coli O127:K63(B8), and synthesis of H-type 3 blood group antigen

International Nuclear Information System (INIS)

Pettit, Nicholas; Styslinger, Thomas; Mei, Zhen; Han, Weiqing; Zhao, Guohui; Wang, Peng George

2010-01-01

Research highlights: → WbiQ is an α1,2-fucosyltransferase from Escherichia coli O127. → WbiQ demonstrates strict substrate specificity for the Gal-β1,3-GalNAc acceptor. → WbiQ was used to synthesize milligram scale of the H-type 3 blood group antigen. -- Abstract: Escherichia coli O127:K63(B8) possesses high human blood group H (O) activity due to its O-antigen repeating unit structure. In this work, the wbiQ gene from E. coli O127:K63(B8) was expressed in E. coli BL21 (DE3) and purified as a fusion protein containing an N-terminal GST affinity tag. Using the GST-WbiQ fusion protein, the wbiQ gene was identified to encode an α1,2-fucosyltransferase using a radioactivity based assay, thin-layer chromatography assay, as well confirming product formation by using mass spectrometry and NMR spectroscopy. The fused enzyme (GST-WbiQ) has an optimal pH range from 6.5 to 7.5 and does not require the presence of a divalent metal to be enzymatically active. WbiQ displays strict substrate specificity, displaying activity only towards acceptors that contain Gal-β1,3-GalNAc-α-OR linkages; indicating that both the Gal and GalNAc residues are vital for enzymatic activity. In addition, WbiQ was used to prepare the H-type 3 blood group antigen, Fuc-α1,2-Gal-β1,3-GalNAc-α-OMe, on a milligram scale.

Annual Surveillance Summary: Escherichia coli (E. coli) Infections in the Military Health System (MHS), 2015

Science.gov (United States)

2017-03-01

Annual Surveillance Summary: Escherichia coli ( E . coli ) Infections in the Military Health System (MHS...or position of the Department of the Navy, Department of Defense, nor the U.S. Government. i i E . coli in the MHS: Annual Summary 2015 Prepared...March 2017 EpiData Center Department NMCPHC-EDC-TR-187-2017 ii ii E . coli in the MHS: Annual Summary 2015 Prepared March 2017 EpiData

Escherichia coli in broiler chickens with airsacculitis

Directory of Open Access Journals (Sweden)

Leandro S. Machado

2014-09-01

Full Text Available ABSTRACT. Machado L.S., do Nascimento E.R., Pereira V.L.A., Abreu D.L.C., Gouvea R. & Santos L.M.M. 2014. [Escherichia coli in broiler chickens with airsacculitis.] Escherichia coli em frangos de corte com aerossaculite. Revista Brasileira de Medicina Veterinária, 36(3:261-265, 2014. Departamento de Medicina Veterinária Preventiva e Saúde Pública, Faculdade de Veterinária, Universidade Federal Fluminense, Rua Dr. Vital Brazil Filho 64, Vital Brazil, Niterói, RJ 24230-340, Brazil. E-mail: leandromachadovet@yahoo.com.br The Brazilian poultry industry grows each year and becomes increasingly representative in the production and export of products. The health care with poultry have accompanied and favored this evolution, however, respiratory agents that affect the weight and carcass quality, continue to cause great damage to the poultry industry. Airsacculitis is considered the main cause of total and partial condemnation of carcasses of broilers, and has been attributed to Mycoplasmosis mostly caused by Mycoplasma gallisepticum (MG and Mycoplasma synoviae (MS and Escherichia coli. The aim of this study was to relate the positivity of MG / MS and E. coli detected by PCR as a risk factor for airsacculitis in condemnation of broilers in Health Inspection Service. We studied 30 broiler poultry slaughtered in a slaughterhouse under Federal Sanitary Inspection, located in the State of Rio de Janeiro. 30 chickens were randomly collected from different lots and tracheas obtained in each PCR. DNA was extracted by phenol-chloroform method and amplified using pairs of “primer”specific for MG, MS and E. coli. Of the 30 chickens analyzed by PCR, 30% (9/30 had lesions in air sacs. None of the birds showed infection with MG and/or MS PCR, however 33.3% (3/9 birds were positive for airsacculitis iss gene from E.coli. E.coli found in broiler chickens that were negative for mycoplasma airsacculitis, implying the presence of such bacteria may be sufficient

Transmission of F4+ E. coli in groups of early weaned piglets

NARCIS (Netherlands)

Geenen, P.L.; Döpfer, D.; Meulen, van der J.; Jong, de M.C.M.

2005-01-01

The aim of this study was to estimate transmission parameters of enterotoxigenic F4+ Escherichia coli F4 (F4+ E. coli) in groups of early weaned piglets with F4-receptor-positive (F4R+) and F4-receptor-negative piglets (F4R[minus sign]). Transmission of F4+ E. coli was quantified in four

Thioredoxin from Escherichia coli

International Nuclear Information System (INIS)

Holmgren, A.; Ohlsson, I.; Grankvist, M.L.

1978-01-01

A competition radioimmunoassay for Escherichia coli thioredoxin using 125 I-labeled thioredoxin-S 2 and a double antibody technique was developed. The method permits determination of picomole amounts of thioredoxin in crude cell extracts and was used to study the localization of thioredoxin cell fractions. E. coli B was calculated to have approximately 10,000 copies of thioredoxin per cell mainly located in the soluble fraction after separation of the membrane and soluble fractions by gentle lysis and centrifugation. E. coli B tsnC mutants which are defective in the replication of phage T7 DNA in vivo and in vitro were examined for their content of thioredoxin. E. coli B tsnC 7004 contained no detectable level of thioredoxin in cell-free extracts examined under a variety of conditions. The results strongly suggest that tsnC 7004 is a nonsense or deletion mutant. Two other E. coli tsnC mutants, 7007 and 7008, contained detectable levels of thioredoxin in crude extracts as measured by thioredoxin reductase and gave similar immunoprecipitation reactions as the parent strain B/1. By radioimmunoassay incompletely cross-reacting material was present in both strains. These results show that tsnC 7007 and 7008 belong to a type of thioredoxin mutants with missence mutations in the thioredoxin gene affecting the function of thioredoxin as subunit in phage T7 DNA polymerase

D10 value determination for Escherichia coli O157:H7 in different cultivations

International Nuclear Information System (INIS)

Oliveira, Sergio Eduardo M. de; Pires, Luis Fernando G.; Vital, Helio de C.

2002-01-01

Escherichia coli serum type O157:H7 is a highly pathogenic bacterium. Inside the human body, that microorganism causes a disease that leads to bloody diarrhea, stoppage of kidney functions and clots in the brain. That type of infection has been related to the consumption of different varieties of foods, mainly meat and other products of animal origin. Irradiation is an efficient method for elimination of pathogenic and spoiling microorganisms in foods. Thus, this work investigates the use of gamma irradiation for elimination of Escherichia coli O157:H7. For that purpose, inoculated samples in trypticase soy broth and saline solution 0,85% media were exposed to several gamma radiation doses. Counting the number of surviving bacteria yielded the following D 10 values for Escherichia coli O157:H7: 98±7 Gy, in trypticase soy broth and 49±4 Gy in saline solution 0,85% medium. (author)

Functional expression of a human GDP-L-fucose transporter in Escherichia coli.

Science.gov (United States)

Förster-Fromme, Karin; Schneider, Sarah; Sprenger, Georg A; Albermann, Christoph

2017-02-01

To investigate the translocation of nucleotide-activated sugars from the cytosol across a membrane into the endoplasmatic reticulum or the Golgi apparatus which is an important step in the synthesis of glycoproteins and glycolipids in eukaryotes. The heterologous expression of the recombinant and codon-adapted human GDP-L-fucose antiporter gene SLC35C1 (encoding an N-terminal OmpA-signal sequence) led to a functional transporter protein located in the cytoplasmic membrane of Escherichia coli. The in vitro transport was investigated using inverted membrane vesicles. SLC35C1 is an antiporter specific for GDP-L-fucose and depending on the concomitant reverse transport of GMP. The recombinant transporter FucT1 exhibited an activity for the transport of 3 H-GDP-L-fucose with a V max of 8 pmol/min mg with a K m of 4 µM. The functional expression of SLC35C1 in GDP-L-fucose overproducing E. coli led to the export of GDP-L-fucose to the culture supernatant. The export of GDP-L-fucose by E. coli provides the opportunity for the engineering of a periplasmatic fucosylation reaction in recombinant bacterial cells.

ANTIMICIROBIAL SUSCEPTIBILITY PATTERNS OF Escherichia coli ...

African Journals Online (AJOL)

DR. AMINU

A total of 56 and 24 strains of E. coli and Shigella sp. isolated from children less than five years with diarrhoea attending 3 ... parasitic infections, as well as food intolerance, reaction to ..... Escherichia coil 0157:H7 as a model of entry of a new.

Distribution of Diverse Escherichia coli between Cattle and Pasture

OpenAIRE

NandaKafle, Gitanjali; Seale, Tarren; Flint, Toby; Nepal, Madhav; Venter, Stephanus N.; Brözel, Volker S.

2017-01-01

Escherichia coli is widely considered to not survive for extended periods outside the intestines of warm-blooded animals; however, recent studies demonstrated that E. coli strains maintain populations in soil and water without any known fecal contamination. The objective of this study was to investigate whether the niche partitioning of E. coli occurs between cattle and their pasture. We attempted to clarify whether E. coli from bovine feces differs phenotypically and genotypically from isola...

Norwegian patients and retail chicken meat share cephalosporin-resistant Escherichia coli and IncK/blaCMY-2 resistance plasmids

DEFF Research Database (Denmark)

Berg, E. S.; Wester, A. L.; Ahrenfeldt, Johanne

2017-01-01

In 2012 and 2014 the Norwegian monitoring programme for antimicrobial resistance in the veterinary and food production sectors (NORM-VET) showed that 124 of a total of 406 samples (31%) of Norwegian retail chicken meat was contaminated with extended-spectrum cephalosporin-resistant Escherichia coli....... The aim of this study was to compare selected cephalosporin-resistant E. coli from humans and poultry to determine their genetic relatedness based on whole genome sequencing (WGS). E. coli representing three prevalent cephalosporin-resistant multi-locus sequence types (STs) isolated from poultry (n=17...

(ESBL) producing Escherichia coli and Klebsiella pneumoniae

African Journals Online (AJOL)

use

2011-11-21

Nov 21, 2011 ... the most common serious bacterial infections in infants ... UTI is a common cause of morbidity .... of ESBL and non-ESBL producing Escherichia coli and Klebsiella pneumonia. ... in hospital and community acquired infections.

Comparative Study on Different Expression Hosts for Alkaline Phytase Engineered in Escherichia coli.

Science.gov (United States)

Chen, Weiwei; Yu, Hongwei; Ye, Lidan

2016-07-01

The application of alkaline phytase as a feed additive is restricted by the poor specific activity. Escherichia coli is a frequently used host for directed evolution of proteins including alkaline phytase towards improved activity. However, it is not suitable for production of food-grade products due to potential pathogenicity. To combine the advantages of different expression systems, mutants of the alkaline phytase originated from Bacillus subtilis 168 (phy168) were first generated via directed evolution in E. coli and then transformed to food-grade hosts B. subtilis and Pichia pastoris for secretory expression. In order to investigate the suitability of different expression systems, the phy168 mutants expressed in different hosts were characterized and compared in terms of specific activity, pH profile, pH stability, temperature profile, and thermostability. The specific activity of B. subtilis-expressed D24G/K70R/K111E/N121S mutant at pH 7.0 and 60 °C was 30.4 U/mg, obviously higher than those in P. pastoris (22.7 U/mg) and E. coli (19.7 U/mg). Moreover, after 10 min incubation at 80 °C, the B. subtilis-expressed D24G/K70R/K111E/N121S retained about 70 % of the activity at pH 7.0 and 37 °C, whereas the values were only about 25 and 50 % when expressed in P. pastoris and E. coli, respectively. These results suggested B. subtilis as an appropriate host for expression of phy168 mutants and that the strategy of creating mutants in one host and expressing them in another might be a new solution to industrial production of proteins with desired properties.

Antimicrobial susceptibilities of avian Escherichia coli isolates in ...

African Journals Online (AJOL)

Colibacillosis is a poultry disease of economic importance in Iran and all around the world. The aim of this study is to test the antibiotic sensitivity of Escherichia coli strains which were isolated in Tabriz. A total of 100 E. coli strains isolated from avian colibacillosis of 50 farms from 2008 to 2009 in Tabriz, were investigated for ...

PART I. ESCHERICHIA COLI

Directory of Open Access Journals (Sweden)

Sanaa Mahdi Oraibi

2016-11-01

Full Text Available The presence of Escherichia coli in the air of facilities involved in management and composting of post-slaughter poultry wastes in selected plants of West Western Pomerania region was studied. Measurements were made on four dates in a variety of weather conditions during the year. The study was conducted at 5 objects that differ in the type of waste and the degree of preparation for composting. These were: chemical treatment and preliminary processing plant, liquid wastes reservoir, platform for preparation of materials for composting, storage of biological sediments, and composting facility. Measurement of bacteria count was carried out in accordance with the applicable procedures on selective chromogenic TBX medium. The assays revealed the presence of E. coli at all test objects, but not always on all measurement dates. It has been shown that the presence of E. coli was from 20 to 3047 CFU∙m-3 of air, although the largest quantities were most frequently detected in the air of the building for post-slaughter waste pre-treatment in chemical treatment plant.

Findings of Escherichia coli and Enterococcus spp. in homemade cheese

Directory of Open Access Journals (Sweden)

Tambur Zoran

2007-01-01

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

Effect of millimeter waves on survival of UVC-exposed Escherichia coli

International Nuclear Information System (INIS)

Rojavin, M.A.; Ziskin, M.C.

1995-01-01

Bacterial cells of the strain Escherichia coli K12 were exposed to millimeter electromagnetic waves (mm waves) with and without additional exposure to ultraviolet light λ = 254 nm (UVC). The mm waves were produced by a medical microwave generator emitting a 4-GHz-wide band around a 61 GHz center frequency and delivering an irradiation of 1mW/cm 2 and a standard absorption rate (SAR) of 84 W/kg to the bacteria. Exposure to the mm waves alone for up to 30 minutes did not change the survival rate of bacteria. Exposure to mm waves followed by UVC irradiation also did not alter the number of surviving E. coli cells in comparison to UVC-treated controls. When mm waves were applied after the UVC exposure, a dose-dependent increase of up to 30% in the survival of E. coli was observed compared to UVC + sham-irradiated bacteria. Because sham controls and experimental samples were maintained under the same thermal conditions, the effect is not likely to be due to heating, although the possibility of nonuniform distribution of microwave heating in different layers of irradiated bacterial suspension cannot be ruled out. The mechanism for this effect appears to involve certain DNA repair systems that act as cellular targets for mm waves

Genes for 7S RNAs can replace the gene for 4.5S RNA in growth of Escherichia coli

DEFF Research Database (Denmark)

Brown, S

1991-01-01

4.5S RNAs of eubacteria and 7S RNAs of archaebacteria and eukaryotes exist in a hairpin conformation. The apex of this hairpin displays structural and sequence similarities among both 4.5S and 7S RNAs. Furthermore, a hyphenated sequence of 16 nucleotides is conserved in all eubacterial 4.5S RNAs...... examined. In this article I report that 7S RNAs that contain this 16-nucleotide sequence are able to replace 4.5S RNAs and permit growth of Escherichia coli....

Escherichia coli pyomyositis in an immunocompromised host.

Science.gov (United States)

Sharma, Umesh; Schwan, William R; Agger, William A

2011-08-01

Pyomyositis due to Escherichia coli (E. coil) is rarely reported in immunocompromised patients with hematological malignancy. We present a case report of a 34-year-old man who developed E. coli pyomyositis as a complication of acute myelogenous leukemia (AML). Magnetic resonance imaging (MRI) of the right hip suggested myofascial infection of the gluteal muscles, and a needle muscle aspiration grew E. coli phylogenetic group B2. The patient responded to intravenous piperacillin/tazobactam followed by prolonged oral levofloxacin. Pyomyositis should be suspected in all immunocompromised patients complaining of muscle pain and may exhibit signs of localized muscle infection. Appropriate antibiotic therapy targeting fluoroquinolone-resistant E. coli should be considered for initial empiric therapy of pyomyositis in immunocompromised patients.

Infectious endocarditis caused by Escherichia coli

DEFF Research Database (Denmark)

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

2011-01-01

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

Mutagenic DNA repair in Escherichia coli

International Nuclear Information System (INIS)

Bridges, B.A.; Sharif, Firdaus

1986-01-01

The authors report a study of the misincorporation step in excision proficient umuC Escherichia coli as revealed by delayed photoreversal and show that it parallels the loss of photoreversibility of mutations induced in isogenic umu + bacteria; in both cases the end-point was mutation to streptomycin resistance. (author)

The 4.5 S RNA gene of Escherichia coli is essential for cell growth

DEFF Research Database (Denmark)

Brown, S; Fournier, M J

1984-01-01

The Escherichia coli gene coding for the metabolically stable 4.5 S RNA (ffs) has been shown to be required for cell viability. Essentiality was demonstrated by examining the recombination behavior of substitution mutations of ffs generated in vitro. Substitution mutants of ffs are able to replace...... the chromosomal allele only in the presence of a second, intact copy of ffs. Independent evidence of essentiality and the finding that 4.5 S RNA is important for protein synthetic activity came from characterization of cells dependent on the lac operon inducer isopropyl-beta-D-thiogalactoside for ffs gene...... expression. Here, a strain dependent on isopropyl-beta-D-thiogalactoside for 4.5 S RNA synthesis was developed by inactivation of the chromosomal ffs allele and lysogenization by a lambda phage containing 4.5 S DNA fused to a hybrid trp-lac promoter. Withdrawal of the thiogalactoside leads to a deficiency...

Receptor for the F4 fimbriae of enterotoxigenic Escherichia coli (ETEC).

Science.gov (United States)

Xia, Pengpeng; Zou, Yajie; Wang, Yiting; Song, Yujie; Liu, Wei; Francis, David H; Zhu, Guoqiang

2015-06-01

Infection with F4(+) enterotoxigenic Escherichia coli (ETEC) responsible for diarrhea in neonatal and post-weaned piglets leads to great economic losses in the swine industry. These pathogenic bacteria express either of three fimbrial variants F4ab, F4ac, and F4ad, which have long been known for their importance in host infection and initiating protective immune responses. The initial step in infection for the bacterium is to adhere to host enterocytes through fimbriae-mediated recognition of receptors on the host cell surface. A number of receptors for ETEC F4 have now been described and characterized, but their functions are still poorly understood. The current review summarizes the latest research addressing the characteristics of F4 fimbriae receptors and the interactions of F4 fimbriae and their receptors on host cells. These include observations that as follows: (1) FaeG mediates the binding activities of F4 and is an essential component of the F4 fimbriae, (2) the F4 fimbrial receptor gene is located in a region of chromosome 13, (3) the biochemical properties of F4 fimbrial receptors that form the binding site of the bacterium are now recognized, and (4) specific receptors confer susceptibility/resistance to ETEC F4 infection in pigs. Characterizing the host-pathogen interaction will be crucial to understand the pathogenicity of the bacteria, provide insights into receptor activation of the innate immune system, and develop therapeutic strategies to prevent this illness.

Escherichia Coli-Lux Biosensor Used to Monitor the Cytotoxicity and Genotoxicity of Pharmacological Residues in Environment

Directory of Open Access Journals (Sweden)

Eliza Hawrylik

2018-05-01

Full Text Available The aim of the study was to evaluate the usefulness of Escherichia coli K-12 RFM 443 recA::lux for cytotoxicity and genotoxicity monitoring of metoprolol in the environment. Metoprolol is one of the most popular cardiac drug which belongs to the group of β–blockers. The drug was applied at concentrations ranging from 0.01 µg/cm3 to 100 µg/cm3. The conducted studies are preliminary studies aimed at validation of the recA::lux gene construct in the direction of determining its sensitivity to metoprolol. The drug concentrations were selected experimentally to obtain a positive luminescence response. Obtained data indicated the influence of metoprolol on lux gene expression and recA promoter activity based on the use of laboratory samples using PBS buffer. Results indicate a potential possibility of using a bacterial biosensor Escherichia coli K - 12 RFM 443 with recA::lux gene fusion in cytotoxicity and genotoxicity monitoring of the cardiac drugs residue in the environment.

MOLECULAR-PHYLOGENETIC CHARACTERIZATION AND ANTIMICROBIAL RESISTANCE OF Escherichia coli ISOLATED FROM GOATS WITH DIARRHEA

Directory of Open Access Journals (Sweden)

Rodrigo Almeida Guimarães

2015-10-01

Full Text Available Neonatal diarrhea determines significant changes in feed conversion, causing productivity loss in caprine herds. The antimicrobial resistance in bacteria is characterized as an important public health issue; therefore, Escherichia coli may be characterized as an important pathogen due to expressing virulence mechanisms responsible for significant clinical conditions in humans and animals. The present study evaluated the presence of E. coli among 117 caprine fecal samples and analyzed the isolates for antimicrobial resistance. Suggestive colonies were submitted to biochemical screening followed by genotypic group determination and phylogenetic analysis; further, the samples were submitted to antimicrobials susceptibility test. E. coli, Salmonella spp, Shigella sonnei and Enterobacter aerogenes were identified. E. coli isolates were phylogenetically classified as B2 (9/39, D (19/39, B1 (7/39 e A (4/29 groups. The analysis of the isolates also revealed the presence of K99 (04/39 and Stx (02/39 virulence factors. Antimicrobial susceptibility test revealed sensitive isolates to Chloramphenicol, Streptomycin, Amoxicillin and Ciprofloxacin, being all resistant to Lincomycin, Vancomycin and Penicillin. The results support the need of establishing restricted protocols for antimicrobial use, a fundamental procedure for health improvement in Brazilian caprine herds.

Cell surface acid-base properties of Escherichia coli and Bacillus brevis and variation as a function of growth phase, nitrogen source and C:N ratio.

Science.gov (United States)

Hong, Yongsuk; Brown, Derick G

2006-07-01

Potentiometric titration has been conducted to systematically examine the acid-base properties of the cell surfaces of Escherichia coli K-12 and Bacillus brevis as a function of growth phase, nitrogen source (ammonium or nitrate), and carbon to nitrogen (C:N) ratio of the growth substrate. The two bacterial species revealed four distinct proton binding sites, with pK(a) values in the range of 3.08-4.05 (pK(1)), 4.62-5.57 (pK(2)), 6.47-7.30 (pK(3)), and 9.68-10.89 (pK(4)) corresponding to phosphoric/carboxylic, carboxylic, phosphoric, and hydroxyl/amine groups, respectively. Two general observations in the data are that for B. brevis the first site concentration (N(1)), corresponding to phosphoric/carboxylic groups (pK(1)), varied as a function of nitrogen source, while for E. coli the fourth site concentration (N(4)), corresponding to hydroxyl/amine groups (pK(4)), varied as a function of C:N ratio. Correspondingly, it was found that N(1) was the highest of the four site concentrations for B. brevis and N(4) was the highest for E. coli. The concentrations of the remaining sites showed little variation. Finally, comparison between the titration data and a number of cell surface compositional studies in the literature indicates one distinct difference between the two bacteria is that pK(4) of the Gram-negative E. coli can be attributed to hydroxyl groups while that of the Gram-positive B. brevis can be attributed to amine groups.

3,4-Dimethoxyphenyl bis-benzimidazole, a novel DNA topoisomerase inhibitor that preferentially targets Escherichia coli topoisomerase I

Science.gov (United States)

Bansal, Sandhya; Sinha, Devapriya; Singh, Manish; Cheng, Bokun; Tse-Dinh, Yuk-Ching; Tandon, Vibha

2012-01-01

Objectives Antibiotic resistance in bacterial pathogens is a serious clinical problem. Novel targets are needed to combat increasing drug resistance in Escherichia coli. Our objective is to demonstrate that 2-(3,4-dimethoxyphenyl)-5-[5-(4-methylpiperazin-1-yl)-1H-benzimidazol-2yl]-1H-benzimidazole (DMA) inhibits E. coli DNA topoisomerase I more strongly than human topoisomerase I. In addition, DMA is non-toxic to mammalian cells at antibiotic dosage level. Methods In the present study, we have established DMA as an antibacterial compound by determining MICs, post-antibiotic effects (PAEs) and MBCs for different standard as well as clinical strains of E. coli. We have described the differential catalytic inhibitory mechanism of bis-benzimidazole, DMA, for human and E. coli topoisomerase I and topoisomerase II by performing different assays, including relaxation assays, cleavage–religation assays, DNA unwinding assays, ethidium bromide displacement assays, decatenation assays and DNA gyrase supercoiling assays. Results DMA significantly inhibited bacterial growth at a very low concentration, but did not affect human cell viability at higher concentrations. Activity assays showed that it preferentially targeted E. coli topoisomerase I over human topoisomerase I, topoisomerase II and gyrase. Cleavage–religation assays confirmed DMA as a poison inhibitor of E. coli topoisomerase I. This study illuminates new properties of DMA, which may be further modified to develop an efficient topoisomerase inhibitor that is selective towards bacterial topoisomerase I. Conclusions This is the first report of a bis-benzimidazole acting as an E. coli topoisomerase I inhibitor. DMA is a safe, non-cytotoxic molecule to human cells at concentrations that are needed for antibacterial activity. PMID:22945915

Effect of high pressurized carbon dioxide on Escherichia coli ...

African Journals Online (AJOL)

Carbon dioxide at high pressure can retard microbial growth and sometimes kill microorganisms depending on values of applied pressure, temperature and exposure time. In this study the effect of high pressurised carbon dioxide (HPCD) on Escherichia coli was investigated. Culture of E. coli was subjected to high ...

Prevalence of Aeromonas species and Escherichia coli in stool ...

African Journals Online (AJOL)

Background: Diarrhoea is one of the main causes of mortality and morbidity in childhood. Bacterial diarrhoea is a common disorder. Aeromonas species and Escherichia coli (E. coli) are some of the aetiological agents associated with diarrhoea in children. Objective: To determine the prevalence of Aeromonas species and ...

Detection of Extended-Spectrum Beta-Lactamase-Producing Escherichia coli in Market-Ready Chickens in Zambia.

Science.gov (United States)

Chishimba, K; Hang'ombe, B M; Muzandu, K; Mshana, S E; Matee, M I; Nakajima, C; Suzuki, Y

2016-01-01

The frequent administering of antibiotics in the treatment of poultry diseases may contribute to emergence of antimicrobial-resistant strains. The objective of this study was to detect the presence of extended-spectrum β-lactamase- (ESBL-) producing Escherichia coli in poultry in Zambia. A total of 384 poultry samples were collected and analyzed for ESBL-producing Escherichia coli. The cultured E. coli isolates were subjected to antimicrobial susceptibility tests and the polymerase chain reaction for detection of bla CTX-M, bla SHV, and bla TEM genes. Overall 20.1%, 77/384, (95% CI; 43.2-65.5%) of total samples analyzed contained ESBL-producing Escherichia coli. The antimicrobial sensitivity test revealed that 85.7% (66/77; CI: 75.7-92) of ESBL-producing E. coli isolates conferred resistance to beta-lactam and other antimicrobial agents. These results indicate that poultry is a potential reservoir for ESBL-producing Escherichia coli. The presence of ESBL-producing Escherichia coli in poultry destined for human consumption requires strengthening of the antibiotic administering policy. This is important as antibiotic administration in food animals is gaining momentum for improved animal productivity in developing countries such as Zambia.

Detection of Extended-Spectrum Beta-Lactamase-Producing Escherichia coli in Market-Ready Chickens in Zambia

Directory of Open Access Journals (Sweden)

K. Chishimba

2016-01-01

Full Text Available The frequent administering of antibiotics in the treatment of poultry diseases may contribute to emergence of antimicrobial-resistant strains. The objective of this study was to detect the presence of extended-spectrum β-lactamase- (ESBL- producing Escherichia coli in poultry in Zambia. A total of 384 poultry samples were collected and analyzed for ESBL-producing Escherichia coli. The cultured E. coli isolates were subjected to antimicrobial susceptibility tests and the polymerase chain reaction for detection of blaCTX-M, blaSHV, and blaTEM genes. Overall 20.1%, 77/384, (95% CI; 43.2–65.5% of total samples analyzed contained ESBL-producing Escherichia coli. The antimicrobial sensitivity test revealed that 85.7% (66/77; CI: 75.7–92 of ESBL-producing E. coli isolates conferred resistance to beta-lactam and other antimicrobial agents. These results indicate that poultry is a potential reservoir for ESBL-producing Escherichia coli. The presence of ESBL-producing Escherichia coli in poultry destined for human consumption requires strengthening of the antibiotic administering policy. This is important as antibiotic administration in food animals is gaining momentum for improved animal productivity in developing countries such as Zambia.

Sunlight inactivation of Escherichia coli in waste stabilization microcosms in a sahelian region (Ouagadougou, Burkina Faso).

Science.gov (United States)

Maïga, Ynoussa; Denyigba, Kokou; Wethe, Joseph; Ouattara, Aboubakar Sidiki

2009-02-09

Experiments on sunlight inactivation of Escherichia coli were conducted from November 2006 to June 2007 in eight outdoors microcosms with different depths filled with maturation pond wastewater in order to determine pond depth influence on sunlight inactivation of E. coli. The long-term aim was to maximize sunlight inactivation of waterborne pathogens in waste stabilization ponds (WSPs) in sahelian regions where number of sunny days enable longer exposure of wastewater to sunlight. The inactivation was followed during daylight from 8.00 h to 17.00 h and during the night. Sunlight inactivation rates (K(S)), as a function of cumulative global solar radiation (insolation), were 16 and 24 times higher than the corresponding dark inactivation (K(D)) rates, respectively in cold and warm season. In warm season, E. coli was inactivated far more rapidly. Inactivation of E. coli follows the evolution of radiation during the day. In shallow depth microcosms, E. coli was inactivated far more rapidly than in high depth microcosms. The physical chemical parameters [pH, dissolved oxygen (DO)] of microcosms water were higher in shallow depth microcosms than in high depth microcosms suggesting a synergistic effect of sunlight and these parameters to damage E. coli. To increase the efficiency of the elimination of waterborne bacteria, the use of maturation ponds with intermediate depths (0.4m) would be advisable in view of the high temperatures and thus evaporation recorded in sahelian regions.

Marker-assisted selection on E. coli F4ab/ac resistance and the effect on neonatal survival in piglets

DEFF Research Database (Denmark)

Jørgensen, Claus Bøttcher; Anderson, Susan I.; Cirera, Susanna

Enterotoxigenic Escherichia coli (ETEC) that express the F4ab or F4ac fimbriae (formerly known as K88ab/ac) are major causes of diarrhea and death in neonatal and young pigs. A locus controlling susceptibility towards ETEC F4ab/ac has previously been mapped to pig chromosome 13q41. A number...

Cloning and expression of the Legionella micdadei "common antigen" in Escherichia coli

DEFF Research Database (Denmark)

Bangsborg, Jette Marie; Collins, M T; Høiby, N

1989-01-01

To study individual Legionella antigens, a Legionella micdadei genomic library in Escherichia coli SC181 was established. Partially Sau3A digested L. micdadei DNA fragments (15-25 kilobase pairs (kb] were cloned into the tetracycline resistance gene of the cosmid vector pHC79. Four thousand...... ampicillin resistant recombinants were obtained; seven hundred were screened for expression of Legionella antigens in Western blot analysis with a polyspecific E. coli-absorbed anti-L. micdadei rabbit antibody. One of the positive clones expressed a 60 kilodalton (K) antigen, which reacted strongly...... will provide important information with respect to genetic vs. antigenic relatedness among Legionellae and other Gram-negative species, as well as to CA structure and possible function....

Multiple-Resistant Commensal Escherichia Coli from Nigerian ...

African Journals Online (AJOL)

Purpose: The antimicrobial susceptibility and virulence traits of 150 strains of Escherichia coli ... and ethical approval was obtained from the Health .... persist in the guts by virtue of the ability of such ... cases of diarrhoea in Ile-Ife and environs.

Synthesis and processing of escherichia-coli tem-beta-lactamase and bacillus-licheniformis alpha-amylase in escherichia-coli : The role of signal peptidase-i

NARCIS (Netherlands)

van Dijl, J M; Smith, H; Bron, Sierd; Venema, Gerard

A mutant of Escherichia coli, in which signal peptidase I synthesis can be regulated, was constructed. The mutant was used to study the effects of signal peptidase I limitation on the synthesis and efficiency of processing of two proteins: the periplasmic E. coli TEM-beta-lactamase and Bacillus

SYNTHESIS AND PROCESSING OF ESCHERICHIA-COLI TEM-BETA-LACTAMASE AND BACILLUS-LICHENIFORMIS ALPHA-AMYLASE IN ESCHERICHIA-COLI : THE ROLE OF SIGNAL PEPTIDASE-I

NARCIS (Netherlands)

van Dijl, J M; SMITH, H; BRON, S; VENEMA, G

A mutant of Escherichia coli, in which signal peptidase I synthesis can be regulated, was constructed. The mutant was used to study the effects of signal peptidase I limitation on the synthesis and efficiency of processing of two proteins: the periplasmic E. coli TEM-beta-lactamase and Bacillus

Characterization of ESBL-producing Escherichia coli and Klebsiella pneumoniae strains isolated from urine of nonhospitalized patients in the Zagreb region

Directory of Open Access Journals (Sweden)

Branka Bedenić,

2010-02-01

Full Text Available Aim To determine the prevalence of ESBL-producing Escherichia coli and Klebsiella pneumoniae strains isolated from urine of nonhospitalized patients during a three-year period, to determine their antibiotic susceptibility, investigate the transfer of ESBL genes with cotransfer of resistance and to characterize isolated beta-lactamases. Methods Antimicrobial susceptibility was determined by disk diffusion and broth microdilution methods. The double-disk test was used for ESBL detection. Transfer of resistance was performed by broth mating method and characterization of isolated beta-lactamases by polymerase chain reaction. Results The prevalence of ESBL-producing E. coli was 1.5% and of K. pneumoniae 4.1% with its different distribution according to patients`age and gender. ESBL-producing K. pneumoniae showed high resistance rates to aminoglycosides, cotrimoxazole, nitrofurantoin and quinolones while ESBL-producing E. coli isolates, with exception of high aminoglycoside resistance, showed low resistance rates to other antibiotics. Successful conjugation of ESBL genes was obtained with 25% E. coli and 76.2% K. pneumoniae strains. Comparing to E. coli, K. pneumoniae strains showed higher rates of aminoglycosideand cotrimoxazole resistance cotransfer. Beta-lactamases of investigated strains belonged to TEM, SHV and CTX-M families.Conclusion The existence of multiple-resistant ESBL-producing E. coli and K. pneumoniae strains was confirmed in observed outpatient population. ESBL-producing K. pneumoniae isolates, in contrast toESBL-producing E. coli, showed higher resistance rates to non-beta-lactam antibiotics, probably caused by cotransfer of resistance genes located on the same plasmid as ESBL genes. It is important to monitor the prevalence of such strains and their possible spreading in the outpatient population of the Zagreb region

EchoBASE: an integrated post-genomic database for Escherichia coli.

Science.gov (United States)

Misra, Raju V; Horler, Richard S P; Reindl, Wolfgang; Goryanin, Igor I; Thomas, Gavin H

2005-01-01

EchoBASE (http://www.ecoli-york.org) is a relational database designed to contain and manipulate information from post-genomic experiments using the model bacterium Escherichia coli K-12. Its aim is to collate information from a wide range of sources to provide clues to the functions of the approximately 1500 gene products that have no confirmed cellular function. The database is built on an enhanced annotation of the updated genome sequence of strain MG1655 and the association of experimental data with the E.coli genes and their products. Experiments that can be held within EchoBASE include proteomics studies, microarray data, protein-protein interaction data, structural data and bioinformatics studies. EchoBASE also contains annotated information on 'orphan' enzyme activities from this microbe to aid characterization of the proteins that catalyse these elusive biochemical reactions.

Isolation and evaluation of cocktail phages for the control of multidrug-resistant Escherichia coli serotype O104: H4 and E. coli O157: H7 isolates causing diarrhea.

Science.gov (United States)

Safwat Mohamed, Doaa; Farouk Ahmed, Eman; Mohamed Mahmoud, Abobakr; Abd El-Baky, Rehab Mahmoud; John, James

2018-02-01

Escherichia coli serotype O157: H7 and E. coli O104: H4 are well known foodborne pathogens causing sever enteric illness. Using bacteriophages as biocontrol agents of some foodborne pathogens and multidrug-resistant (MDR) bacteria has a great attention nowadays. This study aims to test the effect of cocktail phages on the growth of some foodborne pathogens and MDR E. coli. Routine conventional PCR was used to confirm the identification of E. coli isolates. Double-layered culture technique was used to isolate phages from sewage water. Morphology of bacteriophage was described using transmission electron microscopy, and spot test was performed to determine host range of the phage cocktail. Phage cocktail of Siphoviridae and Podoviridae family infecting E. coli O157: H7, E. coli O104: H4 and untypeable E. coli (neither O157 nor O104) has been isolated from sewage water. Phage cocktail showed both lytic and lysogenic activity. Lytic activity was observed against E. coli O157: H7, E. coli O104: H4 isolates, Staphylococcus. aureus ATCC6538 and Pseudomonas aeruginosa ATCC 10145, while the lysogenic activity was observed against the untypeable strain. The tested phage cocktail showed a promising inhibitory action on E. coli O157: H7 and O104: H4, S. aureus ATCC6538 and P. aeruginosa ATCC 10145, suggesting the possibility of its use as a biocontrol tool or as natural food preservatives for many food products. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Changes in Escherichia coli resistance to co-trimoxazole in ...

African Journals Online (AJOL)

In Thyolo district, Malawi, an operational research study is being conducted on the efficacy and feasibility of co-trimoxazole prophylaxis in preventing deaths in HIV-positive patients with tuberculosis (TB). A series of cross-sectional studies were carried out to determine i) whether faecal Escherichia coli (E.coli) resistance to ...

Phylogeny and disease association of Shiga toxin-producing Escherichia coli O91

NARCIS (Netherlands)

Mellmann, Alexander; Fruth, Angelika; Friedrich, Alexander W; Wieler, Lothar H; Harmsen, Dag; Werber, Dirk; Middendorf, Barbara; Bielaszewska, Martina; Karch, Helge

The diversity and relatedness of 100 Shiga toxin-producing Escherichia coli O91 isolates from different patients were examined by multilocus sequence typing. We identified 10 specific sequence types (ST) and 4 distinct clonal groups. ST442 was significantly associated with hemolytic uremic syndrome.

Extended spectrum β-lactamase producing Escherichia coli and Klebsiella pneumoniae: critical tools for antibiotic resistance pattern.

Science.gov (United States)

Padmini, Nagarajan; Ajilda, Antony Alex Kennedy; Sivakumar, Natesan; Selvakumar, Gopal

2017-06-01

Drug resistance is a phenomenon where by an organism becomes fully or partially resistant to drugs or antibiotics being used against it. Antibiotic resistance poses an exacting intimidation for people with underlying medical immune conditions or weakened immune systems. Infections caused by the enzyme extended spectrum β-lactamase (ESBL) producing multi drug resistance (MDR) Enterobacteriaceae especially Escherichia coli and Klebsiella pneumoniae are resistant to a broad range of beta lactams, including third generation cephalosporins. Among all the pathogens, these two MDR E. coli and K. pneumoniae have emerged as one of the world's greatest health threats in past two decades. The nosocomial infections caused by these ESBL producing MDR E. coli and K. pneumoniae complicated the therapy and limit treatment options. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Isolation and genomic characterization of Escherichia coli O157:NM ...

African Journals Online (AJOL)

Human diseases caused by Escherichia coli O157:NM and E. coli O157:H7 strains have been reported throughout the world. In developed countries, serotype O157:H7 represents the major cause of human diseases; however, there have been increasing reports of non-O157 Shiga toxin (Stx)-producing E. coli strains ...

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

Energy Technology Data Exchange (ETDEWEB)

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

2001-02-01

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

Expression and purification of moricin CM4 and human β-defensins 4 in Escherichia coli using a new technology.

Science.gov (United States)

Shen, Yang; Ai, Hong-Xin; Song, Ren; Liang, Zhen-Ning; Li, Jian-Feng; Zhang, Shuang-Quan

2010-10-20

Different strategies have been developed to produce small antimicrobial peptides using recombinant techniques. Here we report a new technology of biosynthesis of moricin CM4 and human β-defensins 4 (HβD4) in the Escherichia coli. The CM4 and HβD4 gene were cloned into a vector containing the tags elastin-like peptide (ELP) and intein to construct the expression vector pET-EI-CM4 and pET-EI-HβD4. All the peptides, expressed as soluble fusions, were isolated from the protein debris by the method called inverse transition cycling (ITC) rather than traditional immobilized metal affinity chromatography (IMAC) and separated from the fusion leader by self-cleavage. Fully reduced peptides that were purified exhibited expected antimicrobial activity. The approach described here is a low-cost, convenient and potential way for generating small antimicrobial peptide. Copyright © 2010 Elsevier GmbH. All rights reserved.

Supercritical CO2 induces marked changes in membrane phospholipids composition in Escherichia coli K12.

Science.gov (United States)

Tamburini, Sabrina; Anesi, Andrea; Ferrentino, Giovanna; Spilimbergo, Sara; Guella, Graziano; Jousson, Olivier

2014-06-01

Supercritical carbon dioxide (SC-CO2) treatment is one of the most promising alternative techniques for pasteurization of both liquid and solid food products. The inhibitory effect of SC-CO2 on bacterial growth has been investigated in different species, but the precise mechanism of action remains unknown. Membrane permeabilization has been proposed to be the first event in SC-CO2-mediated inactivation. Flow cytometry, high performance liquid chromatography–electrospray ionization–mass spectrometry and NMR analyses were performed to investigate the effect of SC-CO2 treatment on membrane lipid profile and membrane permeability in Escherichia coli K12. After 15 min of SC-CO2 treatment at 120 bar and 35 °C, the majority of bacterial cells dissipated their membrane potential (95 %) and lost membrane integrity, as 81 % become partially permeabilized and 18 % fully permeabilized. Membrane permeabilization was associated with a 20 % decrease in bacterial biovolume and to a strong (>50 %) reduction in phosphatidylglycerol (PG) membrane lipids, without altering the fatty acid composition and the degree of unsaturation of acyl chains. PGs are thought to play an important role in membrane stability, by reducing motion of phosphatidylethanolamine (PE) along the membrane bilayer, therefore promoting the formation of inter-lipid hydrogen bonds. In addition, the decrease in intracellular pH induced by SC-CO2 likely alters the chemical properties of phospholipids and the PE/PG ratio. Biophysical effects of SC-CO2 thus cause a strong perturbation of membrane architecture in E. coli, and such alterations are likely associated with its strong inactivation effect.

Erythrocyte and porcine intestinal glycosphingolipids recognized by F4 fimbriae of enterotoxigenic Escherichia coli.

Science.gov (United States)

Coddens, Annelies; Valis, Erik; Benktander, John; Ångström, Jonas; Breimer, Michael E; Cox, Eric; Teneberg, Susann

2011-01-01

Enterotoxigenic F4-fimbriated Escherichia coli is associated with diarrheal disease in neonatal and postweaning pigs. The F4 fimbriae mediate attachment of the bacteria to the pig intestinal epithelium, enabling an efficient delivery of diarrhea-inducing enterotoxins to the target epithelial cells. There are three variants of F4 fimbriae designated F4ab, F4ac and F4ad, respectively, having different antigenic and adhesive properties. In the present study, the binding of isolated F4ab, F4ac and F4ad fimbriae, and F4ab/ac/ad-fimbriated E. coli, to glycosphingolipids from erythrocytes and from porcine small intestinal epithelium was examined, in order to get a comprehensive view of the F4-binding glycosphingolipids involved in F4-mediated hemagglutination and adhesion to the epithelial cells of porcine intestine. Specific interactions between the F4ab, F4ac and F4ad fimbriae and both acid and non-acid glycosphingolipids were obtained, and after isolation of binding-active glycosphingolipids and characterization by mass spectrometry and proton NMR, distinct carbohydrate binding patterns were defined for each fimbrial subtype. Two novel glycosphingolipids were isolated from chicken erythrocytes, and characterized as GalNAcα3GalNAcß3Galß4Glcß1Cer and GalNAcα3GalNAcß3Galß4GlcNAcß3Galß4Glcß1Cer. These two compounds, and lactosylceramide (Galß4Glcß1Cer) with phytosphingosine and hydroxy fatty acid, were recognized by all three variants of F4 fimbriae. No binding of the F4ad fimbriae or F4ad-fimbriated E. coli to the porcine intestinal glycosphingolipids occurred. However, for F4ab and F4ac two distinct binding patterns were observed. The F4ac fimbriae and the F4ac-expressing E. coli selectively bound to galactosylceramide (Galß1Cer) with sphingosine and hydroxy 24:0 fatty acid, while the porcine intestinal glycosphingolipids recognized by F4ab fimbriae and the F4ab-fimbriated bacteria were characterized as galactosylceramide, sulfatide (SO(3)-3Galß1Cer), sulf

Photoreactivating enzyme from Escherichia coli

International Nuclear Information System (INIS)

Snapka, R.M.; Fuselier, C.O.

1977-01-01

Escherichia coli photoreactivating enzyme (PRE) has been purified in large amounts from an E.coli strain lysogenic for a defective lambda bacteriophage carrying the phr gene. The resulting enzyme had a pH optimum of 7.2 and an ionic strength optimum of 0.18. It consisted of an apoprotein and cofactor, both of which were necessary for catalytic activity. The apoprotein had a monomer molecular weight of 35,200 and showed stable aggregates under denaturing conditions. The amino acid analysis of the E.coli enzyme was very similar to that of the photoreactivating enzyme from orchid seedlings (Cattelya aurantiaca). Both had arginine at the amino terminus. The cofactor, like the holoenzyme, showed absorption, magnetic circular dichroism, and emission properties indicative of an adenine moiety. Although the isolated enzyme had an action spectrum which peaked at about 360 nm, neither the cofactor, apoenzyme nor holoenzyme showed any detectable absorption between 300 and 400 nm. (author)

Photoreactivating enzyme from Escherichia coli

Energy Technology Data Exchange (ETDEWEB)

Snapka, R M; Fuselier, C O [California Univ., Irvine (USA)

1977-05-01

Escherichia coli photoreactivating enzyme (PRE) has been purified in large amounts from an E.coli strain lysogenic for a defective lambda bacteriophage carrying the phr gene. The resulting enzyme had a pH optimum of 7.2 and an ionic strength optimum of 0.18. It consisted of an apoprotein and cofactor, both of which were necessary for catalytic activity. The apoprotein had a monomer molecular weight of 35,200 and showed stable aggregates under denaturing conditions. The amino acid analysis of the E.coli enzyme was very similar to that of the photoreactivating enzyme from orchid seedlings (Cattelya aurantiaca). Both had arginine at the amino terminus. The cofactor, like the holoenzyme, showed absorption, magnetic circular dichroism, and emission properties indicative of an adenine moiety. Although the isolated enzyme had an action spectrum which peaked at about 360 nm, neither the cofactor, apoenzyme nor holoenzyme showed any detectable absorption between 300 and 400 nm.

Study of the action of {sup 60}Co gamma radiation on Salmonella poona, Escherichia coli and Alicyclobacillus acidoterrestris in mango pulp; Estudo da acao da radiacao gama de {sup 60}Co sobre Salmonella poona, Escherichia coli e Alicyclobacillus acidoterrestris em polpa de manga congelada

Energy Technology Data Exchange (ETDEWEB)

Pereira, Marco Antonio dos Santos

2009-07-01

The application of non-thermal treatments has proven effective in inhibiting bacteria such as Salmonella and Escherichia coli. Mango is a fruit of national consumption with a great exportation potential. Meanwhile, outbreaks of food borne disease related to mango consumption caused mistrust on the degree of food security offered by the product. The objective of this work was to establish the radioresistance of bacteria Escherichia coli, Salmonella Poona and Alicyclobacillus acidoterrestris on the mango pulp by the calculation of the D10 values and to know the radiation effect on the sensory characteristics of the fruit pulp. The microbiological profile of frozen mango pulp available at the local market was also established using conventional methods of plating and Most Probable Number (MPN). The pulps experimentally inoculated with the bacteria listed above were irradiated with doses of 0, 1, 2, 3, 4 and 5kGy in a {sup 60}Co source. The sensory analysis was performed using a dose of 5 kGy, using the triangular test and the test of acceptance with hedonic scale. The results of this study show that the quality of mango pulp sell in the local market is not satisfactory in accordance with the standards established by the Brazilian law and the literature, showing the need of using other tools to achieve acceptable levels of quality. The D10 values obtained are in the range of 1.01 and 1.09kGy for E. coli ATCC 8739, 0.60 and 0.98kGy for S. poona and 0.72 e 0.88kGy for A. acidoterrestris respectively. The triangular test showed that a 5kGy radiation dose changed the sensory characteristics of mango pulp. Nevertheless, sensory analysis of a food product prepared with the irradiated pulp obtained good acceptance in the attributes of global appearance, flavor and aroma. (author)

Study of the action of {sup 60}Co gamma radiation on Salmonella poona, Escherichia coli and Alicyclobacillus acidoterrestris in mango pulp;Estudo da acao da radiacao gama de {sup 60}Co sobre Salmonella poona, Escherichia coli and Alicyclobacillus acidoterrestris em polpa de manga congelada

Energy Technology Data Exchange (ETDEWEB)

Pereira, Marco Antonio dos Santos

2009-07-01

The application of non-thermal treatments has proven effective in inhibiting bacteria such as Salmonella and Escherichia coli. Mango is a fruit of national consumption with a great exportation potential. Meanwhile, outbreaks of foodborne disease related to mango consumption caused mistrust on the degree of food security offered by the product. The objective of this work was to establish the radioresistance of bacteria Escherichia coli, Salmonella Poona and Alicyclobacillus acidoterrestris on the mango pulp by the calculation of the D10 values and to know the radiation effect on the sensory characteristics of the fruit pulp. The microbiological profile of frozen mango pulp available at the local market was also established using conventional methods of plating and Most Probable Number (MPN). The pulps experimentally inoculated with the bacteria listed above were irradiated with doses of 0, 1, 2, 3, 4 and 5 kGy in a {sup 60}Co source. The sensory analysis was performed using a dose of 5 kGy, using the triangular test and the test of acceptance with hedonic scale. The results of this study show that the quality of mango pulp sell in the local market is not satisfactory in accordance with the standards established by the Brazilian law and the literature, showing the need of using other tools to achieve acceptable levels of quality. The D10 values obtained are in the range of 1.01 and 1.09 kGy for E. coli ATCC 8739, 0.60 and 0.98 kGy for S. poona and 0.72 and 0.88 kGy for A. acidoterrestris respectively. The triangular test showed that a 5 kGy radiation dose changed the sensory characteristics of mango pulp. Nevertheless, sensory analysis of a food product prepared with the irradiated pulp obtained good acceptance in the attributes of global appearance, flavor and aroma. (author)

Specific binding of lactoferrin to Escherichia coli isolated from human intestinal infections

International Nuclear Information System (INIS)

Naidu, S.S.; Erdei, J.; Forsgren, A.; Naidu, A.S.; Czirok, E.; Gado, I.; Kalfas, S.; Thoren, A.

1991-01-01

The degrees of human lactoferrin (HLf) and bovine lactoferrin (BLf) binding in 169 Escherichia coli strains isolated from human intestinal infections, and in an additional 68 strains isolated from healthy individuals, were examined in a 125 I-labelled protein binding assay. The binding was expressed as a percentage calculated from the total labelled ligand added to bacteria. The HLf and BLf binding to E. coli was in the range 3.7 to 73.4% and 4.8 to 61.6%, respectively. Enterotoxigenic strains demonstrated a significantly higher HLf binding (median = 19%) than enteropathogenic, enteroinvasive, enterohaemorrhagic strains or normal intestinal E. coli isolates (medians 6 to 9). Enteropathogenic strains belonging to serotypes O44 and O127 demonstrated significantly higher HLf binding compared to O26, O55, O111, O119 and O126. No significant differences in the degree of HLf or BLf binding were found between aerobactin-producing and non-producing strains. The interaction was further characterized in a high Lf-binging EPEC strain, E34663 (serotype O127). The binding was stable in the pH range 4.0 to 7.5, did not dissociate in the presence of 2M NaCl or 2M urea, and reached saturation within two h. Unlabelled HLf and BLf displaced the 125 I-HLf binding to E34663 in a dose-dependent manner. Apo- and iron-saturated forms of Lf demonstrated similar binding to E34663. Among various unlabelled subephithelial matrix proteins and carbohydrates tested (in 10 4 -fold excess) only fibronectin and fibrinogen caused a moderate inhibition of 125 I-HLf binding. According to Scatchard plot analysis, 5,400 HLf-binding sites/cell, with an affinity constant (K a ) of 1.4 x 10 -7 M, were estimated in strain E34663. These data establish the presence of a specific Lf-binding mechanism in E. coli. (au)

Vaginal Lactobacillus isolates inhibit uropathogenic Escherichia coli.

OpenAIRE

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

2006-01-01

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

The iron uptake mechanisms of enteroinvasive Escherichia coli Mecanismos de captação de ferro de Escherichia coli enteroinvasora

Directory of Open Access Journals (Sweden)

Agda Andrade

2000-09-01

Full Text Available Enteroinvasive Escherichia coli strains (EIEC of different serotypes isolated from patients with acute diarrhea were examined for the ability to produce siderophores and iron-regulated outer membrane proteins (IROMP. For iron starvation cultures were grown at 37°C in LB supplied with 200 muM of a-alpha’dypirydil. All strains produced enterobactin and twelve (40% produced aerobactin. The strains showed IROMP varying from 67-82 kDa. Proteins were either induced or stimulated by the iron starvation. Differences were observed in the electrophoretic profile among the serotypes, originating 5 electrophoretic profiles. All serotypes expressed proteins of 82 kDa (FepA and 76 kDa (IutA (except serotype O28ac:H- that did not produce the 76 kDa protein. Several strains (O29:H-, O144:H-, O152:H-, and O167:H- expressed IutA in the outer membrane, in the absence of aerobactin production. Additionally to well characterized proteins (FepA and IutA, we found two IROMP of unknown function in some serotypes: a 71 kDa protein was detected in three profiles and a 67 kDa protein was present in serotype O152:H-. Moreover, two bands (39 and 43 kDa which were not iron-regulated bound specifically to human lactoferrin.Cepas de Escherichia coli enteroinvasora de diferentes sorotipos isoladas de pacientes com diarréia aguda foram examinadas quanto a capacidade de produzir sideróforos e proteínas de membrana externa reguladas pelo ferro (IROMP. O crescimento bacteriano em meio com deficiência em Fe foi obtido em caldo Lúria acrescido de 200 mM de alfa-a’dipiridil. Todas as cepas produziram enterobactina e 40% produziram aerobactina. As cepas produziram IROMPs com MM variando de 82-67 kDa. As proteínas foram induzidas ou estimuladas pela deficiência de ferro. Diferenças foram observadas no perfil eletroforético entre os sorotipos, originando 5 perfis eletroforéticos. Todos os sorotipos, com exceção do sorotipo O28ac:H- (onde a proteína de 76 kDa não foi

Autodisplay of an avidin with biotin-binding activity on the surface of Escherichia coli.

Science.gov (United States)

Pardavé-Alejandre, H D; Alvarado-Yaah, J E; Pompa-Mera, E N; Muñoz-Medina, J E; Sárquiz-Martínez, B; Santacruz-Tinoco, C E; Manning-Cela, R G; Ortíz-Navarrete, V; López-Macías, C; González-Bonilla, C R

2018-03-01

To display a recombinant avidin fused to the autotransporter ShdA to bind biotinylated molecules on the surface of Escherichia coli. Two chimeric protein constructs containing avidin fused to the autotransporter ShdA were expressed on the surface of Escherichia coli DH5α. One fusion protein contained 476 amino acids of the ShdA α and β domains, whereas the second consisted of a 314 amino acid from α and truncated β domains. Protein production was verified by SDS-PAGE using an antibody to the molecular FLAG-tag. The surface display of the avidin-shdA fusion protein was confirmed by confocal microscopy and flow cytometry analysis, and the biotin-binding activity was evaluated by fluorescence microscopy and flow cytometry using biotin-4-fluorescein and biotinylated-ovalbumin (OVA). Expression of a recombinant avidin with biotin-binding activity on the surface of E. coli was achieved using the autotransporter ShdA. This system is an alternative to bind biotinylated molecules to E. coli.

Timeliness of Surveillance during Outbreak of Shiga Toxin–producing Escherichia coli Infection, Germany, 2011

OpenAIRE

Altmann, Mathias; Wadl, Maria; Altmann, Doris; Benzler, Justus; Eckmanns, Tim; Krause, Gérard; Spode, Anke; an der Heiden, Matthias

2011-01-01

In the context of a large outbreak of Shiga toxin–producing Escherichia coli O104:H4 in Germany, we quantified the timeliness of the German surveillance system for hemolytic uremic syndrome and Shiga toxin–producing E. coli notifiable diseases during 2003–2011. Although reporting occurred faster than required by law, potential for improvement exists at all levels of the information chain.

An Effect of Cadmium and Lead Ions on Escherichia coli with the Cloned Gene for Metallothionein (MT-3) Revealed by Electrochemistry

International Nuclear Information System (INIS)

Adam, Vojtech; Chudobova, Dagmar; Tmejova, Katerina; Cihalova, Kristyna; Krizkova, Sona; Guran, Roman; Kominkova, Marketa; Zurek, Michal; Kremplova, Monika; Jimenez, Ana Maria Jimenez; Konecna, Marie

2014-01-01

This study was focused on the application of electrochemical methods for studying of bacterial strains Escherichia coli and Escherichia coli expressing human metallothionein gene (MT-3) before and after the application of cadmium and/or lead ions in four concentrations (25, 50, 75 and 150 μM). Bacterial strains Escherichia coli and Escherichia coli expressing human metallothionein gene (MT-3) were used like model organisms for studying of metals influence to metallothionein expression. Metallothionein was isolated using fast protein liquid chromatography and quantified by electrochemical methods. The occurrence of metallothionein in E.coli was confirmed by gel electrophoresis by the presence of the bands at 15 (MT dimer) and 22 kDa (MT trimer). The changes in electrochemical records due to the interactions of metallothioneins (MT-3 and MT-2A) with cadmium and lead ions showed decline of Cat2 signal of MT with the increasing interaction time because of metal ions binding to cysteines. Electrochemical determination also revealed that Cd(II) remains in E. coli cells in the higher amount than Pb (II). Opposite situation was found at E. coli–MT-3 strain. The antimicrobial effect of cadmium ions was determined by IC 50 and was statistically calculated as 39.2 and 95.5 μM for E. coli without cloned MT-3 and E. coli carrying MT-3 gene, respectively. High provided concentration IC 50 in strains after lead ions application (352.5 μM for E. coli without cloning and 207.0 μM for E. coli carrying cloned MT-3 gene) indicates lower toxicity of lead ions on bacterial strains compared to the cadmium ions

Crystallization and preliminary crystallographic analysis of the bacterial capsule assembly-regulating tyrosine phosphatases Wzb of Escherichia coli and Cps4B of Streptococcus pneumoniae

International Nuclear Information System (INIS)

Huang, Hexian; Hagelueken, Gregor; Whitfield, Chris; Naismith, James H.

2009-01-01

The crystallization is reported of two bacterial tyrosine phosphatases which belong to different enzyme families despite their ability to catalyse identical reactions. Bacterial tyrosine kinases and their cognate phosphatases are key players in the regulation of capsule assembly and thus are important virulence determinants of these bacteria. Examples of the kinase/phosphatase pairing are found in Gram-negative bacteria such as Escherichia coli (Wzc and Wzb) and in Gram-positive bacteria such as Streptococcus pneumoniae (CpsCD and CpsB). Although Wzb and Cps4B are both predicted to dephosphorylate the C-terminal tyrosine cluster of their cognate tyrosine kinase, they appear on the basis of protein sequence to belong to quite different enzyme classes. Recombinant purified proteins Cps4B of S. pneumoniae TIGR4 and Wzb of E. coli K-30 have been crystallized. Wzb crystals belonged to space-group family P3 x 21 and diffracted to 2.7 Å resolution. Crystal form I of Cps4B belonged to space-group family P4 x 2 1 2 and diffracted to 2.8 Å resolution; crystal form II belonged to space group P2 1 2 1 2 1 and diffracted to 1.9 Å resolution

Antibiotic resistant Escherichia coli in southeastern Australian pig herds and implications for surveillance.

Science.gov (United States)

van Breda, L K; Dhungyel, O P; Ward, M P

2018-02-01

To investigate public health implications of antibiotics to control post-weaning scours, we surveyed 22 commercial pig herds in southeastern Australia. Fifty faecal samples per herd were collected from pre- and post-weaned piglets. Presumptive Escherichia coli isolates were confirmed by MALDI-TOF MS. Isolates (n = 325) were screened for susceptibility to 19 veterinary antibiotics using MIC broth microdilution. All 325 E. coli isolates underwent further testing against 27 antibiotics used in human medicine and were screened for ETEC adhesin and enterotoxin genes (F4 (K88), F5 (K99), F6 (987P), F18, F41, STa, STb, Stx2e and LT) by multiplex PCR. Isolates identified as phenotypically resistant to third-generation cephalosporin (3GC) and aminoglycoside antibiotics were screened by multiplex PCR/reverse line blot to detect common β-lactam and aminoglycosides resistance genes, confirmed by sequencing. Twenty (6.1%) of the E. coli isolates were resistant to 3GC antibiotics and 24 (7.4%) to the aminoglycoside antibiotic gentamicin. Genetic analysis revealed six different extended spectrum β-lactamase (ESBL) genes (blaCTX-M-1, -14, -15, -27, blaSHV-12 and blaCMY-2-like genes), four of which have not been previously reported in Australian pigs. Critically, the prevalence of 3GC resistance was higher in non-pathogenic (non-ETEC) isolates and those from clinically normal (non-diarrhoeal) samples. This highlights the importance of non-ETECE. coli as reservoirs of antimicrobial resistance genes in piglet pens. Antimicrobial resistance surveillance in pig production focused on diagnostic specimens from clinically-affected animals might be potentially misleading. We recommend that surveillance for emerging antimicrobial resistance such as to 3GC antibiotics should include clinically healthy pigs. © 2017 Blackwell Verlag GmbH.

Growth modeling of uropathogenic Escherichia coli in ground chicken meat

Science.gov (United States)

Extraintestinal Pathogenic Escherichia coli (ExPEC), including Uropathogenic E. coli (UPEC), are common contaminants in poultry meat, and are a major pathogen associated with inflammatory bowel disease, ulcerative colitis, sepsis, and urinary tract infections. The purpose of this study was to determ...

Induction of prophage lambda during the division cycle of Escherichia coli

Energy Technology Data Exchange (ETDEWEB)

Worsey, M J; Wilkins, B M [Leicester Univ. (UK). Dept. of Genetics

1975-01-01

When synchronous populations of Escherichia coli B/r (lambda) were exposed to low doses of ultraviolet light, the yield of infective centres varied with cell age. The yield was highest if the lysogenic bacteria were irradiated at a time which coincides approximately with the termination of rounds of DNA replication and it was lowest when dividing cells were irradiated. No such variation was detected following either irradiation of excision-defective lysogenic cells or thermal induction of lambda cI857 prophage in irradiated bacteria. It is suggested that the variation reflects a relationship between prophage induction and inhibition of cell division. This hypothesis is supported by data showing that irradiation-promoted induction and curtailed division in E. coli K12 dnaA mutants which were dividing in the absence of DNA replication.

Induction of prophage lambda during the division cycle of Escherichia coli

International Nuclear Information System (INIS)

Worsey, M.J.; Wilkins, B.M.

1975-01-01

When synchronous populations of Escherichia coli B/r (lambda) were exposed to low doses of ultraviolet light, the yield of infective centres varied with cell age. The yield was highest if the lysogenic bacteria were irradiated at a time which coincides approximately with the termination of rounds of DNA replication and it was lowest when dividing cells were irradiated. No such variation was detected following either irradiation of excision-defective lysogenic cells or thermal induction of lambda cI857 prophage in irradiated bacteria. It is suggested that the variation reflects a relationship between prophage induction and inhibition of cell division. This hypothesis is supported by data showing that irradiation-promoted induction and curtailed division in E. coli K12 dnaA mutants which were dividing in the absence of DNA replication. (orig.) [de

Correlation of radiation sensitivity and nitrofurantoin sensitivity of Escherichia coli K-12

International Nuclear Information System (INIS)

Kloeck, K.

1981-01-01

The Uvr- and rec-mutants of E.coli K-12 have been tested with a view to their radiation- and nitrofuration sensitivity. The tests showed that all mutants tested were more radiation- and NF-sensitive than the wild type AB 1157. When the NF-sensitivity had been compared to the UV- and X-ray sensitivity it became obvious that the NF-sensitivity is correlated to the UV-sensitivity. Studies carried out with regard to the time dependence of the NF-effect on E.coli showed that the effect of NF on E. Coli became weaker after about 1 1/2 to 2 hours. That is possibly caused by the fact that the E. coli bacteria succeed in reducing the NF to an inactive form. By means of nitrosoguanidine mutants of E-coli AB 1157 had been induced and by means of the Replicite Plating Method, NF-sensible mutants had been isolated from the plutonium mixture. Among the mutants which had been isolated by this method, 74% had been more UV-sensitive than the wild type and 55% more X-ray sensitive. Thus NF-sensitive mutants have not necessarily to be considered as rec-mutants as there are also uvr-mutants in the mixture. (orig.) [de

A Selected Lactobacillus rhamnosus Strain Promotes EGFR-Independent Akt Activation in an Enterotoxigenic Escherichia coli K88-Infected IPEC-J2 Cell Model

OpenAIRE

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

2015-01-01

Enterotoxigenic Escherichia coli (ETEC) are important intestinal pathogens that cause diarrhea in humans and animals. Although probiotic bacteria may protect against ETEC-induced enteric infections, the underlying mechanisms are unknown. In this study, porcine intestinal epithelial J2 cells (IPEC-J2) were pre-incubated with and without Lactobacillus rhamnosus ATCC 7469 and then exposed to F4+ ETEC. Increases in TLR4 and NOD2 mRNA expression were observed at 3 h after F4+ ETEC challenge, but t...

Study of the action of 60Co gamma radiation on Salmonella poona, Escherichia coli and Alicyclobacillus acidoterrestris in mango pulp

International Nuclear Information System (INIS)

Pereira, Marco Antonio dos Santos

2009-01-01

The application of non-thermal treatments has proven effective in inhibiting bacteria such as Salmonella and Escherichia coli. Mango is a fruit of national consumption with a great exportation potential. Meanwhile, outbreaks of food borne disease related to mango consumption caused mistrust on the degree of food security offered by the product. The objective of this work was to establish the radioresistance of bacteria Escherichia coli, Salmonella Poona and Alicyclobacillus acidoterrestris on the mango pulp by the calculation of the D10 values and to know the radiation effect on the sensory characteristics of the fruit pulp. The microbiological profile of frozen mango pulp available at the local market was also established using conventional methods of plating and Most Probable Number (MPN). The pulps experimentally inoculated with the bacteria listed above were irradiated with doses of 0, 1, 2, 3, 4 and 5kGy in a 60 Co source. The sensory analysis was performed using a dose of 5 kGy, using the triangular test and the test of acceptance with hedonic scale. The results of this study show that the quality of mango pulp sell in the local market is not satisfactory in accordance with the standards established by the Brazilian law and the literature, showing the need of using other tools to achieve acceptable levels of quality. The D10 values obtained are in the range of 1.01 and 1.09kGy for E. coli ATCC 8739, 0.60 and 0.98kGy for S. poona and 0.72 e 0.88kGy for A. acidoterrestris respectively. The triangular test showed that a 5kGy radiation dose changed the sensory characteristics of mango pulp. Nevertheless, sensory analysis of a food product prepared with the irradiated pulp obtained good acceptance in the attributes of global appearance, flavor and aroma. (author)

Study of the action of 60Co gamma radiation on Salmonella poona, Escherichia coli and Alicyclobacillus acidoterrestris in mango pulp

International Nuclear Information System (INIS)

Pereira, Marco Antonio dos Santos

2009-01-01

The application of non-thermal treatments has proven effective in inhibiting bacteria such as Salmonella and Escherichia coli. Mango is a fruit of national consumption with a great exportation potential. Meanwhile, outbreaks of foodborne disease related to mango consumption caused mistrust on the degree of food security offered by the product. The objective of this work was to establish the radioresistance of bacteria Escherichia coli, Salmonella Poona and Alicyclobacillus acidoterrestris on the mango pulp by the calculation of the D10 values and to know the radiation effect on the sensory characteristics of the fruit pulp. The microbiological profile of frozen mango pulp available at the local market was also established using conventional methods of plating and Most Probable Number (MPN). The pulps experimentally inoculated with the bacteria listed above were irradiated with doses of 0, 1, 2, 3, 4 and 5 kGy in a 60 Co source. The sensory analysis was performed using a dose of 5 kGy, using the triangular test and the test of acceptance with hedonic scale. The results of this study show that the quality of mango pulp sell in the local market is not satisfactory in accordance with the standards established by the Brazilian law and the literature, showing the need of using other tools to achieve acceptable levels of quality. The D10 values obtained are in the range of 1.01 and 1.09 kGy for E. coli ATCC 8739, 0.60 and 0.98 kGy for S. poona and 0.72 and 0.88 kGy for A. acidoterrestris respectively. The triangular test showed that a 5 kGy radiation dose changed the sensory characteristics of mango pulp. Nevertheless, sensory analysis of a food product prepared with the irradiated pulp obtained good acceptance in the attributes of global appearance, flavor and aroma. (author)

(ESBL) producing Escherichia coli and Klebsiella pneumoniae

African Journals Online (AJOL)

Emerging antibiotic resistance due to extended spectrum β-lactamase (ESBL) production limited the use of β-lactam antibiotics against Escherichia coli and Klebsiella pneumoniae. This observational study was conducted at the Microbiology department of the Children's Hospital, Lahore Pakistan, from June, 2009 to ...

Antibiotic resistance properties of uropathogenic Escherichia coli ...

African Journals Online (AJOL)

Purpose: To investigate the antibiotic resistance pattern of uropathogenic Escherichia coli (UPEC) strains isolated from pregnant women with history of recurrent urinary tract infections (RUTIs) and healthy pregnant women. Methods: A total of 485 high vaginal swab specimens were collected from pregnant women with ...

Hydrogen production by recombinant Escherichia coli strains

Science.gov (United States)

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

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

Science.gov (United States)

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 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.

A High-Throughput Oxidative Stress Biosensor Based on Escherichia coli roGFP2 Cells Immobilized in a k-Carrageenan Matrix

Directory of Open Access Journals (Sweden)

Lia Ooi

2015-01-01

Full Text Available Biosensors fabricated with whole-cell bacteria appear to be suitable for detecting bioavailability and toxicity effects of the chemical(s of concern, but they are usually reported to have drawbacks like long response times (ranging from hours to days, narrow dynamic range and instability during long term storage. Our aim is to fabricate a sensitive whole-cell oxidative stress biosensor which has improved properties that address the mentioned weaknesses. In this paper, we report a novel high-throughput whole-cell biosensor fabricated by immobilizing roGFP2 expressing Escherichia coli cells in a k-carrageenan matrix, for the detection of oxidative stress challenged by metalloid compounds. The E. coli roGFP2 oxidative stress biosensor shows high sensitivity towards arsenite and selenite, with wide linear range and low detection limit (arsenite: 1.0 × 10−3–1.0 × 101 mg·L−1, LOD: 2.0 × 10−4 mg·L−1; selenite: 1.0 × 10−5–1.0 × 102 mg·L−1, LOD: 5.8 × 10−6 mg·L−1, short response times (0–9 min, high stability and reproducibility. This research is expected to provide a new direction in performing high-throughput environmental toxicity screening with living bacterial cells which is capable of measuring the bioavailability and toxicity of environmental stressors in a friction of a second.

Escherichia coli pathotypes in Pakistan from consecutive floods in 2010 and 2011.

Science.gov (United States)

Bokhari, Habib; Shah, Muhammad Ali; Asad, Saba; Akhtar, Sania; Akram, Muhammad; Wren, Brendan W

2013-03-01

This study compares Escherichia coli pathotypes circulating among children in Pakistan during the floods of 2010 and 2011 and from sporadic cases outside flood affected areas. Using multiplex polymerase chain reaction 115 of 205 stool samples (56.29%) were positive for diarrheagenic E. coli from specimens taken during the floods compared with 50 of 400 (12.5%) stool samples being positive for sporadic cases. The E. coli pathotypes were categorized as Enteropathogenic E. coli 33 (28.69%) and 13 (26%), Enterotoxigenic E. coli 29 (25.21%) and 15 (30%), Enteroaggregative E. coli 21 (18.2%) and 18 (36%), Enterohemorrhagic E. coli 5 (4.34%) and 1 (2%) from flood and sporadic cases, respectively. Furthermore, patients co-infected with more than one pathotype were 26 (22.60%) and 3 (6%) from flood and sporadic cases, respectively. The study shows an unexpectedly high rate of isolation of E. coli pathotypes suggesting Pakistan as an endemic region that requires active surveillance particularly during flood periods.

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

Directory of Open Access Journals (Sweden)

Farhad Safarpordehkordi

2014-08-01

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

Difference in melting profiles of gamma irradiated DNA from chicken erythrocytes and from Escherichia coli B/r

International Nuclear Information System (INIS)

Kopff, J.; Miller, G.; Leyko, W.

1977-01-01

Effects of gamma irradiation on melting curves of DNA from chicken erythrocytes and Escherichia coli B/r were compared. Considerable changes, following gamma irradiation in the case of chicken erythrocytes DNA and no changes in the case of DNA from Escherichia coli B/r were observed. To explain the lack of changes in gamma irradiated samples of DNA from Escherichia coli B/r it was assumed that the original effects of irradiation were obscured by the process of renaturation of DNA. To exclude the above mentioned effect, examination of gamma irradiated DNA from Escherichia coli B/r was carried out with the addition of formaldehyde immediately after irradiation of the sample. Using this procedure changes of melting profiles of DNA from Escherichia coli B/r were demonstrated. (author)

Expression of green fluorescent protein (GFPuv) in Escherichia coli ...

African Journals Online (AJOL)

Administrator

The recombinant green fluorescent protein (GFPuv) was expressed by transformed cells of Escherichia coli DH5-α grown in LB/amp broth at 37oC, for 8 h and 24 h. To evaluate the effectiveness of different parameters to improve the expression of GFPuv by E. coli, four variable culturing conditions were set up for assays by ...

The organization of the fuc regulon specifying L-fucose dissimilation in Escherichia coli K12 as determined by gene cloning.

Science.gov (United States)

Chen, Y M; Zhu, Y; Lin, E C

1987-12-01

In Escherichia coli the six known genes specifying the utilization of L-fucose as carbon and energy source cluster at 60.2 min and constitute a regulon. These genes include fucP (encoding L-fucose permease), fucI (encoding L-fucose isomerase), fucK (encoding L-fuculose kinase), fucA (encoding L-fuculose 1-phosphate aldolase), fucO (encoding L-1,2-propanediol oxidoreductase), and fucR (encoding the regulatory protein). In this study the fuc genes were cloned and their positions on the chromosome were established by restriction endonuclease and complementation analyses. Clockwise, the gene order is: fucO-fucA-fucP-fucI-fucK-fucR. The operons comprising the structural genes and the direction of transcription were determined by complementation analysis and Southern blot hybridization. The fucPIK and fucA operons are transcribed clockwise. The fucO operon is transcribed counterclockwise. The fucR gene product activates the three structural operons in trans.

Recombinant Tyrosinase from Polyporus arcularius: Overproduction in Escherichia coli, Characterization, and Use in a Study of Aurones as Tyrosinase Effectors

Czech Academy of Sciences Publication Activity Database

Marková, Eva; Kotík, Michael; Křenková, Alena; Man, Petr; Haudecoeur, R.; Boumendjel, A.; Hardré, R.; Mekmouche, Y.; Dezord-Courvoisier, E.; Réglier, M.; Martínková, Ludmila

2016-01-01

Roč. 64, č. 14 (2016), s. 2925-2931 ISSN 0021-8561 R&D Projects: GA MŠk LD12049; GA MŠk LO1509; GA TA ČR TA04021212 Institutional support: RVO:61388971 Keywords : tyrosinase * Polyporus arcularius * Escherichia coli Subject RIV: CE - Biochemistry Impact factor: 3.154, year: 2016

Timeliness of Surveillance during Outbreak of Shiga Toxin–producing Escherichia coli Infection, Germany, 2011

Science.gov (United States)

Wadl, Maria; Altmann, Doris; Benzler, Justus; Eckmanns, Tim; Krause, Gérard; Spode, Anke; an der Heiden, Matthias

2011-01-01

In the context of a large outbreak of Shiga toxin–producing Escherichia coli O104:H4 in Germany, we quantified the timeliness of the German surveillance system for hemolytic uremic syndrome and Shiga toxin–producing E. coli notifiable diseases during 2003–2011. Although reporting occurred faster than required by law, potential for improvement exists at all levels of the information chain. PMID:22000368

Optimization of plasmid electrotransformation into Escherichia coli ...

African Journals Online (AJOL)

In order to improve electroporation, optical density of bacteria, recovery time and electrical parameter (field strength and capacitance) were optimized using the Taguchi statistical method. ANOVA of obtained data indicated that the optimal conditions of electrotransformation of pET-28a (+) plasmid into Escherichia coli ...

Cloning and characterization of GDP-perosamine synthetase (Per) from Escherichia coli O157:H7 and synthesis of GDP-perosamine in vitro

International Nuclear Information System (INIS)

Zhao Guohui; Liu Jun; Liu Xiang; Chen Min; Zhang Houcheng; Wang, Peng George

2007-01-01

GDP-perosamine synthetase (Per, E.C. not yet classified) is important to the synthesis of Escherichia coli O157:H7 O-antigen. The mutant in per gene can disrupt the synthesis of O157 O-antigen. In this study, GDP-perosamine synthetase was cloned from E. coli O157:H7 and over-expressed in E. coli BL21 (DE3). The recombinant His-tagged Per fusion protein was a decamer with molecular weight of 431 kDa. The optimal pH value of this recombinant protein was 7.5. The divalent ions had no significant effect on Per-catalyzed reaction. The K m and K cat /K m for GDP-4-keto-6-deoxy-D-mannose were 0.09 mM and 2.1 x 10 5 M -1 S -1 , and those for L-glutamate were 2 mM and 0.52 x 10 5 M -1 S -1 , respectively. Per was used to synthesize GDP-perosamine from GDP-mannose together with recombinant GDP-mannose dehydratase (GMD, E.C. 4.2.1.47). The purified GDP-perosamine was identified by MS and NMR. In summary, this work provided a feasible approach for the synthesis of GDP-perosamine which can lead to the study of LPS biosynthesis of pathogenic E. coli O157:H7

Engineering of Escherichia coli for the synthesis of N-hydroxycinnamoyl tryptamine and serotonin.

Science.gov (United States)

Lee, Su Jin; Sim, Geun-Young; Lee, Youngshim; Kim, Bong-Gyu; Ahn, Joong-Hoon

2017-11-01

Plants synthesize various phenol amides. Among them, hydroxycinnamoyl (HC) tryptamines and serotonins exhibit antioxidant, anti-inflammatory, and anti-atherogenic activities. We synthesized HC-tryptamines and HC-serotonin from several HCs and either tryptamine or serotonin using Escherichia coli harboring the 4CL (4-coumaroyl CoA ligase) and CaHCTT [hydroxycinnamoyl-coenzyme A:serotonin N-(hydroxycinnamoyl)transferase] genes. E. coli was engineered to synthesize N-cinnamoyl tryptamine from glucose. TDC (tryptophan decarboxylase) and PAL (phenylalanine ammonia lyase) along with 4CL and CaHCTT were introduced into E. coli and the phenylalanine biosynthetic pathway of E. coli was engineered. Using this strategy, approximately 110.6 mg/L of N-cinnamoyl tryptamine was synthesized. By feeding 100 μM serotonin into the E. coli culture, which could induce the synthesis of cinnamic acid or p-coumaric acid, more than 99 μM of N-cinnamoyl serotonin and N-(p-coumaroyl) serotonin were synthesized.

Mechanisms of the radioprotective effect of cysteamine in Escherichia coli

International Nuclear Information System (INIS)

Korystov, Yu.N.; Vexler, F.B.

1988-01-01

The values of the oxygen effect (m) and the maximal protective effect of cysteamine (DMF*) were estimated for four Escherichia coli strains: AB1157 (wild type), AB1886 (uvrA), AB2463 (recA), and p3478 (polA). A correlation made between DMF* and m as well as the kinetics of the increase of DMF with oxygen depletion showed that the protective effect of cysteamine is realized by three mechanisms: (i) anoxia achieved by oxygen reduction, with the DMF varying from 2.2 to 4.2 for different E. coli strains (this protection is the major contribution to the entire mechanism); (ii) lowering of the indirect radiation effect; i.e., for 50 mM cysteamine DMF does not exceed 1.1; and (iii) increase of the efficiency of enzymatic repair. The latter effect of cysteamine is registered only with the wild-type E. coli, the DMF being not less than 1.4

Hemolytic Porcine Intestinal Escherichia coli without Virulence-Associated Genes Typical of Intestinal Pathogenic E. coli ▿ †

Science.gov (United States)

Schierack, Peter; Weinreich, Joerg; Ewers, Christa; Tachu, Babila; Nicholson, Bryon; Barth, Stefanie

2011-01-01

Testing 1,666 fecal or intestinal samples from healthy and diarrheic pigs, we obtained hemolytic Escherichia coli isolates from 593 samples. Focusing on hemolytic E. coli isolates without virulence-associated genes (VAGs) typical for enteropathogens, we found that such isolates carried a broad variety of VAGs typical for extraintestinal pathogenic E. coli. PMID:21965399

Environmental Escherichia coli: Ecology and public health implications - A review

Science.gov (United States)

Jang, Jeonghwan; Hur, Hor-Gil; Sadowsky, Michael J.; Byappanahalli, Muruleedhara; Yan, Tao; Ishii, Satoshi

2017-01-01

Escherichia coli is classified as a rod-shaped, Gram-negative bacterium in the family Enterobacteriaceae. The bacterium mainly inhabits the lower intestinal tract of warm-blooded animals, including humans, and is often discharged into the environment through feces or wastewater effluent. The presence of E. coli in environmental waters has long been considered as an indicator of recent fecal pollution. However, numerous recent studies have reported that some specific strains of E. coli can survive for long periods of time, and potentially reproduce, in extra-intestinal environments. This indicates that E. coli can be integrated into indigenous microbial communities in the environment. This naturalization phenomenon calls into question the reliability of E. coli as a fecal indicator bacterium (FIB). Recently, many studies reported that E. coli populations in the environment are affected by ambient environmental conditions affecting their long-term survival. Large-scale studies of population genetics provide the diversity and complexity of E. coli strains in various environments, affected by multiple environmental factors. This review examines the current knowledge on the ecology of E. coli strains in various environments in regards to its role as a FIB and as a naturalized member of indigenous microbial communities. Special emphasis is given on the growth of pathogenic E. coli in the environment, and the population genetics of environmental members of the genus Escherichia. The impact of environmental E. coli on water quality and public health is also discussed.

Resistência a antimicrobianos dependente do sistema de efluxo multidrogas em Escherichia coli isoladas de leite mastítico Antimicrobial resistance dependent on multidrugs efflux in Escherichia coli isolated from the mastitic milk

Directory of Open Access Journals (Sweden)

M.A.S. Moreira

2008-12-01

Full Text Available Identificaram-se e caracterizaram-se a resistência e a multirresistência aos principais antimicrobianos usados no tratamento de mastite bovina causada por Escherichia coli. A concentração inibitória mínima (MIC e o sistema de efluxo foram detectados pelas curvas de crescimento, com base na densidade óptica, em diferentes concentrações da droga e na presença e na ausência do desacoplador da força próton-motora (PMF. E. coli 1 foi resistente à neomicina e à gentamicina; E. coli 3 e 4, à tetraciclina e à estreptomicina; e E. coli 2 e 6 à gentamicina. E. coli 5 apresentou modelo de sensibilidade. Observou-se que MICs de todos os antimicrobianos dos multirresistentes (E. coli 1, 3 e 4 diminuíram na presença do desacoplador, o que sugere sistema de efluxo multidrogas. Após cura, apenas E. coli 1 apresentou modelo de sensibilidade, porém não houve alterações das MICs, antes e após adição do desacoplador. Os resultados indicam possível presença de mecanismo de resistência dependente da PMF codificado, ou parte dele, em plasmídeo.Resistance and multiresistance to main antimicrobials used for treating bovine mastitis caused by Escherichia coli were identified and characterized. The minimal inhibitory concentration (MIC and efflux systems were detected by the use of growth curves based on optical density at different drug concentrations and both presence and absence of uncoupler of the proton-motive force (PMF. E. coli 1 was resistant to neomycin and gentamycin, E. coli 3 and 4 were resistant to tetracycline and streptomycin, whereas E. coli 2 and 6 were resistant to gentamycin. E. coli 5 showed sensibility model. MICs of all antimicrobials of the multiresistant samples (E. coli 1, 3, and 4 were decreased in presence of the uncoupler, therefore suggesting the presence of the multidrug efflux system. After healing, only E. coli 1 showed sensibility model, however no alteration occurred in MIC(s before and after adding the

Impact of metal ion homeostasis of genetically modified Escherichia coli Nissle 1917 and K12 (W3110) strains on colonization properties in the murine intestinal tract.

Science.gov (United States)

Kupz, Andreas; Fischer, André; Nies, Dietrich H; Grass, Gregor; Göbel, Ulf B; Bereswill, Stefan; Heimesaat, Markus M

2013-09-01

Metal ions are integral parts of pro- as well as eukaryotic cell homeostasis. Escherichia coli proved a valuable in vitro model organism to elucidate essential mechanisms involved in uptake, storage, and export of metal ions. Given that E. coli Nissle 1917 is able to overcome murine colonization resistance, we generated several E. coli Nissle 1917 mutants with defects in zinc, iron, copper, nickel, manganese homeostasis and performed a comprehensive survey of the impact of metal ion transport and homeostasis for E. coli colonization capacities within the murine intestinal tract. Seven days following peroral infection of conventional mice with E. coli Nissle 1917 strains exhibiting defined defects in zinc or iron uptake, the respective mutant and parental strains could be cultured at comparable, but low levels from the colonic lumen. We next reassociated gnotobiotic mice in which the microbiota responsible for colonization resistance was abrogated by broad-spectrum antibiotics with six different E. coli K12 (W3110) mutants. Seven days following peroral challenge, each mutant and parental strain stably colonized duodenum, ileum, and colon at comparable levels. Taken together, defects in zinc, iron, copper, nickel, and manganese homeostasis do not compromise colonization capacities of E. coli in the murine intestinal tract.

Phosphoribosylpyrophosphate (PRPP)-less mutants of Escherichia coli

DEFF Research Database (Denmark)

Hove-Jensen, Bjarne

1989-01-01

A DNA fragment encoding kanamycin resistance was inserted in vitro into a plasmid-borne prs gene encoding phosphoribosylpyrophosphate synthetase of Escherichia coli. The resulting plasmids were subsequently transferred to the chromosome by homologous recombination and the haploid strains prs-3::Kan......R and prs-4::KanR were obtained. These strains were fully viable, but required guanosine, uridine, histidine, tryptophan and nicotinamide mononucleotide. There was no phosphoribosylpyrophosphate synthetase activity or phosphoribosylpyrophosphate pool in the mutant strains. These results show...

FimH-mediated autoaggregation of Escherichia coli

DEFF Research Database (Denmark)

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

2001-01-01

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

Update of incidence and antimicrobial susceptibility trends of Escherichia coli and Klebsiella pneumoniae isolates from Chinese intra-abdominal infection patients.

Science.gov (United States)

Zhang, Hui; Yang, Qiwen; Liao, Kang; Ni, Yuxing; Yu, Yunsong; Hu, Bijie; Sun, Ziyong; Huang, Wenxiang; Wang, Yong; Wu, Anhua; Feng, Xianju; Luo, Yanping; Chu, Yunzhuo; Chen, Shulan; Cao, Bin; Su, Jianrong; Duan, Qiong; Zhang, Shufang; Shao, Haifeng; Kong, Haishen; Gui, Bingdong; Hu, Zhidong; Badal, Robert; Xu, Yingchun

2017-12-18

To evaluate in vitro susceptibilities of aerobic and facultative Gram-negative bacterial (GNB) isolates from intra-abdominal infections (IAIs) to 12 selected antimicrobials in Chinese hospitals from 2012 to 2014. Hospital acquired (HA) and community acquired (CA) IAIs were collected from 21 centers in 16 Chinese cities. Extended spectrum beta-lactamase (ESBL) status and antimicrobial susceptibilities were determined at a central laboratory using CLSI broth microdilution and interpretive standards. From all isolated strains the Enterobacteriaceae (81.1%) Escherichia coli accounted for 45.4% and Klebsiella pneumoniae for 20.1%, followed by Enterobacter cloacae (5.2%), Proteus mirabilis (2.1%), Citrobacter freundii (1.8%), Enterobacter aerogenes (1.8%), Klebsiella oxytoca (1.4%), Morganella morganii (1.2%), Serratia marcescens (0.7%), Citrobacter koseri (0.3%), Proteus vulgaris (0.3%) and others (1.0%). Non- Enterobacteriaceae (18.9%) included Pseudomonas aeruginosa (9.8%), Acinetobacter baumannii (6.7%), Stenotrophomonas maltophilia (0.9%), Aeromonas hydrophila (0.4%) and others (1.1%). ESBL-screen positive Escherichia coli isolates (ESBL+) showed a decreasing trend from 67.5% in 2012 to 58.9% in 2014 of all Escherichia coli isolates and the percentage of ESBL+ Klebsiella pneumoniae isolates also decreased from 2012 through 2014 (40.4% to 26.6%), which was due to reduced percentages of ESBL+ isolates in HA IAIs for both bacteria. The overall susceptibilities of all 5160 IAI isolates were 87.53% to amikacin (AMK), 78.12% to piperacillin-tazobactam (TZP) 81.41% to imipenem (IMP) and 73.12% to ertapenem (ETP). The susceptibility of ESBL-screen positive Escherichia coli strains was 96.77%-98.8% to IPM, 91.26%-93.16% to ETP, 89.48%-92.75% to AMK and 84.86%-89.34% to TZP, while ESBL-screen positive Klebsiella pneumoniae strains were 70.56%-80.15% susceptible to ETP, 80.0%-87.5% to IPM, 83.82%-87.06% to AMK and 63.53%-68.38% to TZP within the three year study

Inhibition of Escherichia Coli, Salmonella and Staphylococcus ...

African Journals Online (AJOL)

Escherichia coli O157:H7, Salmonella typhimurium and Staphylococcus. aureus are of great concern to the food industry, especially in foods stored under refrigerated conditions where, unlike most food-borne pathogens are able to multiply. This investigation was conducted to study the inhibitory effect of some spice ...

Prevalence of Arcobacter, Escherichia coli, Staphylococcus aureus ...

African Journals Online (AJOL)

In this study, varying level of resistance of Escherichia coli 66(84.6%), Salmonella 6(100%) and Arcobacter 57(100%) to amoxicillin was observed. The susceptibility pattern indicates that the bacterial isolates exhibited a varying level of resistance to two or more antimicrobial agents with maximum resistance to amoxicillin.

Small noncoding RNA GcvB is a novel regulator of acid resistance in Escherichia coli

Directory of Open Access Journals (Sweden)

Jin Ye

2009-04-01

Full Text Available Abstract Background The low pH environment of the human stomach is lethal for most microorganisms; but not Escherichia coli, which can tolerate extreme acid stress. Acid resistance in E. coli is hierarchically controlled by numerous regulators among which are small noncoding RNAs (sncRNA. Results In this study, we individually deleted seventy-nine sncRNA genes from the E. coli K12-MG1655 chromosome, and established a single-sncRNA gene knockout library. By systematically screening the sncRNA mutant library, we show that the sncRNA GcvB is a novel regulator of acid resistance in E. coli. We demonstrate that GcvB enhances the ability of E. coli to survive low pH by upregulating the levels of the alternate sigma factor RpoS. Conclusion GcvB positively regulates acid resistance by affecting RpoS expression. These data advance our understanding of the sncRNA regulatory network involved in modulating acid resistance in E. coli.

Profiling of Escherichia coli Chromosome database.

Science.gov (United States)

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.

QSAR study of benzimidazole derivatives inhibition on escherichia coli methionine Aminopeptidase

Directory of Open Access Journals (Sweden)

Zahra Garkani-Nejad

2010-06-01

Full Text Available The paper describes a quantitative structure-activity relationship (QSAR study of IC50 values of benzimidazole derivatives on escherichia coli methionine aminopeptidase. The activity of the 32 inhibitors has been estimated by means of multiple linear regression (MLR and artificial neural network (ANN techniques. The results obtained using the MLR method indicate that the activity of derivatives of benzimidazoles on CoII-loaded escherichia coli methionine aminopeptidase depend on different parameters containing topological descriptors, Burden eigen values, 3D MoRSE descriptors and 2D autocorrelation descriptors. The best artificial neural network model is a fully-connected, feed forward back propagation network with a 5-4-1 architecture. Standard error for the training set using this network was 0.193 with correlation coefficient 0.996 and for the prediction set standard error was 1.41 with correlation coefficient 0.802. Comparison of the quality of the ANN with different MLR models showed that ANN has a better predictive power.

Adsorption of Escherichia coli Using Bone Char | Rezaee | Journal ...

African Journals Online (AJOL)

The aim of study was providing a novel adsorbent for the removal of Escherichia coli (E.coli) as a microbial model from contaminated air especially in hospital units using bone char (BC). The BC was prepared from cattle animal bone by pyrolysis in a furnace at 450°C for 2 h. The characteristics of BC have been determined ...

Radiocomplexation and evaluation of the 99mTc-Gemifloxacin in artificially Escherichia coli infected mice

International Nuclear Information System (INIS)

Erfani, M.; Shafiei, M.; Rekabgardan, M.; Mortazavi, P.

2016-01-01

Gemifloxacin as a broad spectrum quinolone antibacterial agent was radiocomplexed with high activity of 99m Tc and was evaluated as an infection imaging agent in artificially Escherichia coli (E. Coli) infected mice. 99m Tc-Gemifloxacin with high specific activity (0.148 GBq/μmol) and labeling yield (98.60 ± 0.70 %) was obtained. Our main achievement was high accumulation in the E. Coli infected right thigh muscle in mice (T/NT = 1.89 at 4 h post injection) which may diagnostically be beneficial to distinguish sites of E. Coli infection. (author)

Exposure to Sub-lethal 2,4-Dichlorophenoxyacetic Acid Arrests Cell Division and Alters Cell Surface Properties in Escherichia coli

Science.gov (United States)

Bhat, Supriya V.; Kamencic, Belma; Körnig, André; Shahina, Zinnat; Dahms, Tanya E. S.

2018-01-01

Escherichia coli is a robust, easily adaptable and culturable bacterium in vitro, and a model bacterium for studying the impact of xenobiotics in the environment. We have used correlative atomic force – laser scanning confocal microscopy (AFM-LSCM) to characterize the mechanisms of cellular response to the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D). One of the most extensively used herbicides world-wide, 2,4-D is known to cause hazardous effects in diverse non-target organisms. Sub-lethal concentrations of 2,4-D caused DNA damage in E. coli WM1074 during short exposure periods which increased significantly over time. In response to 2,4-D, FtsZ and FtsA relocalized within seconds, coinciding with the complete inhibition of cell septation and cell elongation. Exposure to 2,4-D also resulted in increased activation of the SOS response. Changes to cell division were accompanied by concomitant changes to surface roughness, elasticity and adhesion in a time-dependent manner. This is the first study describing the mechanistic details of 2,4-D at sub-lethal levels in bacteria. Our study suggests that 2,4-D arrests E. coli cell division within seconds after exposure by disrupting the divisome complex, facilitated by dissipation of membrane potential. Over longer exposures, 2,4-D causes filamentation as a result of an SOS response to oxidative stress induced DNA damage. PMID:29472899

Metabolic flux balance analysis and the in silico analysis of Escherichia coli K-12 gene deletions

Directory of Open Access Journals (Sweden)

Edwards Jeremy S

2000-07-01

Full Text Available Abstract Background Genome sequencing and bioinformatics are producing detailed lists of the molecular components contained in many prokaryotic organisms. From this 'parts catalogue' of a microbial cell, in silico representations of integrated metabolic functions can be constructed and analyzed using flux balance analysis (FBA. FBA is particularly well-suited to study metabolic networks based on genomic, biochemical, and strain specific information. Results Herein, we have utilized FBA to interpret and analyze the metabolic capabilities of Escherichia coli. We have computationally mapped the metabolic capabilities of E. coli using FBA and examined the optimal utilization of the E. coli metabolic pathways as a function of environmental variables. We have used an in silico analysis to identify seven gene products of central metabolism (glycolysis, pentose phosphate pathway, TCA cycle, electron transport system essential for aerobic growth of E. coli on glucose minimal media, and 15 gene products essential for anaerobic growth on glucose minimal media. The in silico tpi-, zwf, and pta- mutant strains were examined in more detail by mapping the capabilities of these in silico isogenic strains. Conclusions We found that computational models of E. coli metabolism based on physicochemical constraints can be used to interpret mutant behavior. These in silica results lead to a further understanding of the complex genotype-phenotype relation. Supplementary information: http://gcrg.ucsd.edu/supplementary_data/DeletionAnalysis/main.htm

RNase H and replication of ColE1 DNA in Escherichia coli.

OpenAIRE

Naito, S; Uchida, H

1986-01-01

Amber mutations within the rnh (RNase H) gene of Escherichia coli K-12 were isolated by selecting for bacteria capable of replicating in a sup+ background replication-defective cer-6 mutant of the ColE1 replicon. The cer-6 mutation is an alteration of one base pair located 160 nucleotides upstream of the unique replication origin of this plasmid. Subsequently, we determined the DNA alterations present within these mutants. ColE1 DNA replicated in rnh(Am) recA cells, indicating that (i) RNase ...

Cysteine Addition Promotes Sulfide Production and 4-Fold Hg(II)-S Coordination in Actively Metabolizing Escherichia coli.

Science.gov (United States)

Thomas, Sara A; Gaillard, Jean-François

2017-04-18

The bacterial uptake of mercury(II), Hg(II), is believed to be energy-dependent and is enhanced by cysteine in diverse species of bacteria under aerobic and anaerobic conditions. To gain insight into this Hg(II) biouptake pathway, we have employed X-ray absorption spectroscopy (XAS) to investigate the relationship between exogenous cysteine, cellular metabolism, cellular localization, and Hg(II) coordination in aerobically respiring Escherichia coli (E. coli). We show that cells harvested in exponential growth phase consistently display mixtures of 2-fold and 4-fold Hg(II) coordination to sulfur (Hg-S 2 and Hg-S 4 ), with added cysteine enhancing Hg-S 4 formation. In contrast, cells in stationary growth phase or cells treated with a protonophore causing a decrease in cellular ATP predominantly contain Hg-S 2 , regardless of cysteine addition. Our XAS results favor metacinnabar (β-HgS) as the Hg-S 4 species, which we show is associated with both the cell envelope and cytoplasm. Additionally, we observe that added cysteine abiotically oxidizes to cystine and exponentially growing E. coli degrade high cysteine concentrations (100-1000 μM) into sulfide. Thermodynamic calculations confirm that cysteine-induced sulfide biosynthesis can promote the formation of dissolved and particulate Hg(II)-sulfide species. This report reveals new complexities arising in Hg(II) bioassays with cysteine and emphasizes the need for considering changes in chemical speciation as well as growth stage.

prevalence of escherichia coli 0157:h7 in fresh and roasted beef

African Journals Online (AJOL)

DR. AMINU

The prevalence of Enterohemorrhagic Escherichia coli 0157:H7 in 300 fresh beef and 150 roasted beef samples from ... likely cause of E. coli O157:H7 infection is undercooked ground beef. ..... coli O157:H7 in a sheep model. Appl. Environ.

Escherichia coli enteroagregativa como agente provocador de diarreia persistente: modelo experimental utilizando microscopia óptica de luz Escherichia coli enteroagregativa como agente provocador de diarrea persistente: modelo experimental utilizando microscopia óptica de luz Enteroaggregative Escherichia coli as a cause of persistent diarrhea: an experimental model using light microscopy

Directory of Open Access Journals (Sweden)

Jacy Alves B. de Andrade

2011-03-01

Full Text Available OBJETIVO: Avaliar interações de amostras de Escherichia coli enteroagregativa com tecido intestinal humano, a fim de documentar potenciais alterações em diferentes regiões do trato digestivo. MÉTODOS: Amostras de Escherichia coli enteroagregativa isoladas das fezes de crianças com diarreia persistente e a amostra protótipo 042, isolada de uma criança com diarreia em Lima, no Peru (controle positivo, foram analisadas por microscopia óptica de luz após semeadura em cultura de orgão in vitro de fragmentos de mucosa ileal e colônica. Foram analisadas as interações entre as diferentes cepas de Escherichia coli enteroagregativa e as mucosas ileal e colônica. RESULTADOS: A análise por microscopia óptica de luz indicou associação destes micro-organismos com o epitélio, provocando alterações. As cepas estudadas aderiram a ambas as regiões avaliadas (intestino delgado distal e grosso e causaram alterações, especialmente naquelas áreas onde interagiram diretamente com o epitélio. No íleo, algumas regiões mostraram internalização secundária. CONCLUSÕES: Esses agentes podem causar diarreia persistente por meio de alterações no intestino delgado, no qual ocorrem as funções digestivo-absortivas. As lesões inflamatórias descritas na mucosa colônica poderiam explicar a colite mostrada em algumas crianças infectadas por Escherichia coli enteroagregativa.OBJETIVO: Evaluar interacciones de muestras de Escherichia coli enteroagregativa (EAEC con tejido intestinal humano, a fin de documentar potenciales alteraciones en distintas regiones del tracto digestivo (intestino delgado distal e intestino grueso y definir, con eso, su rol en la persistencia del proceso diarreico. MÉTODOS: Muestras de EAEC aislada de las heces de niños con diarrea persistente y la muestra prototipo 042, aislada de un niño con diarrea en Lima, Perú (control positivo fueron analizadas por microscopía óptica de luz (ML después de siembra en cultura

Phleomycin-induced lethality and DNA degradation in Escherichia coli K12

Energy Technology Data Exchange (ETDEWEB)

Nakayama, H

1975-01-01

The cell lethality and DNA fragmentation caused by phleomycin (PM) were studied in E. coli K12 strains with special reference to the effects of repair or recombination deficiencies and metabolic inhibitors. Unlike excision-defective derivatives of E. coli B, uvrA, uvrB, and uvrC mutants of strain K12 showed no peculiarities compared with wild type in regard to cell survival. Likewise, mutant alleles at uvrD and polA loci had no effect. In contrast, rec mutants were more sensitive to PM-killing than were rec/sup +/ strains. PM-induced strand breakage in DNA was observed in all strains tested including the above-mentioned mutants. There was no significant distinction between the uvr mutants and the wild type strain, indicating that the uvr-endonuclease was not responsible for the strand breaks. Involvement of endonuclease I was also ruled out. At least some of the PM-induced strand breaks were repairable. PM-induced lethality and strand breakage were totally dependent on energy supply. Inhibition of protein synthesis resulted in a partial and parallel suppression of the two effects. Our results suggest that the lethality is due to DNA strand breakage and the repair of such damage is postulated to be controlled by rec genes.

GLYCOSYLATED YGHJ POLYPEPTIDES FROM ENTEROTOXIGENIC ESCHERICHIA COLI (ETEC)

DEFF Research Database (Denmark)

2017-01-01

The present invention relates to glycosylated YghJ polypeptides from or derived from enterotoxigenic Escherichia coli (ETEC) that are immunogenic. In particular, the present invention relates to compositions or vaccines comprising the polypeptides and their application in immunization, vaccination...

Purification and Characterization of Recombinant Vaccinia L1R Protein from Escherichia coli

Science.gov (United States)

2016-08-01

RECOMBINANT VACCINIA L1R PROTEIN FROM ESCHERICHIA COLI 1. INTRODUCTION 1.1 Background Vaccinia virus (VACV) is the active component of the...the preparation of the recombinant VACV L1R protein fragment by denaturing , refolding, and purifying material expressed into inclusion bodies in...PURIFICATION AND CHARACTERIZATION OF RECOMBINANT VACCINIA L1R PROTEIN FROM ESCHERICHIA COLI ECBC-TR-1370

Deuterium incorporation into Escherichia-coli proteins

DEFF Research Database (Denmark)

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

1986-01-01

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

Alteration of lysine 178 in the hinge region of the Escherichia coli ada protein interferes with activation of ada, but not alkA, transcription.

OpenAIRE

Saget, B M; Shevell, D E; Walker, G C

1995-01-01

The ada gene of Escherichia coli K-12 encodes the 39-kDa Ada protein, which consists of two domains joined by a hinge region that is sensitive to proteolytic cleavage in vitro. The amino-terminal domain has a DNA methyltransferase activity that repairs the S-diastereoisomer of methylphosphotriesters while the carboxyl-terminal domain has a DNA methyltransferase activity that repairs O6-methylguanine and O4-methylthymine lesions. Transfer of a methyl group to Cys-69 by repair of a methylphosph...

The antimutagenic effect of monoterpenes against UV-irradiation-, 4NQO- and t-BOOH-induced mutagenesis in coli

Directory of Open Access Journals (Sweden)

Nikolić Biljana

2011-01-01

Full Text Available The aim of this work was to investigate the antimutagenic potential of monoterpenes from sage and basil in Escherichia coli. The mutagenic potential of monoterpenes was pre-screened with Salmonella/microsome reversion assay in strain TA100 and no mutagenic effect was detected. The antimutagenic potential against UV- 4NQO- and t-BOOH induced mutagenesis was evaluated in E. coli K12 and E. coli WP2 by reversion assays. The obtained results indicate that camphor and thujone reduce UV- and 4NQO-induced mutations; myrcene reduces t-BOOH-induced mutations, while eucalyptol and linalool reduce mutagenicity by all tested mutagens. Considering evolutionary conservation of DNA repair and antioxidative protection, the obtained results indicate that further antigenotoxicity studies should be undertaken in eukaryotes.

An accelerated method for the detection of Extended-Spectrum B- Lactamases in urinary isolates of Escherichia Coli and Klebsiella pneumoniae

International Nuclear Information System (INIS)

Kader, Abdulrahman A.; Kumar, A.; Krishna, A.; Zaman, M.N.

2006-01-01

We prospectively studied an accelerated phenotypic method by incorporating the double disk synergy test in the standard Kirby-Bauer disk diffusion susceptibility testing, to evaluate a protocol for the rapid detection of extended of extended-spectrum B-lactamases (ESBL) in urinary isolates of Escherichia coli (E. coli) and Klebsiella, pneumoniae (K. pneumoniae). All ESBL-positive isolates were confirmed by the standard Clinical Laboratory Standards Institute (CLSI) confirmatory disk diffusion method. Between November 2004 and December 2005, a total of 6988 urine specimens were analyzed of which 776 (11%) showed significant growth. They included E. coli in 577 cases (74%) and K. pneumoniae in 199 (25.6%). Of these, 63 E. coli (8%) and 15 K. pneumoniae (7.5%) were positive for ESBL by the accelerated and CLSI methods. Compared to the standard CLSI method, the accelerated method reduced the ESBL detection time from two days to one day. We conclude that the accelerated ESBL detection technique used by us in this study is a reliable and rapid method for detecting ESBL in urinary isolates of E. coli and K. pneumoniae. (author)

Environmental Escherichia coli: ecology and public health implications-a review.

Science.gov (United States)

Jang, J; Hur, H-G; Sadowsky, M J; Byappanahalli, M N; Yan, T; Ishii, S

2017-09-01

Escherichia coli is classified as a rod-shaped, Gram-negative bacterium in the family Enterobacteriaceae. The bacterium mainly inhabits the lower intestinal tract of warm-blooded animals, including humans, and is often discharged into the environment through faeces or wastewater effluent. The presence of E. coli in environmental waters has long been considered as an indicator of recent faecal pollution. However, numerous recent studies have reported that some specific strains of E. coli can survive for long periods of time, and potentially reproduce, in extraintestinal environments. This indicates that E. coli can be integrated into indigenous microbial communities in the environment. This naturalization phenomenon calls into question the reliability of E. coli as a faecal indicator bacterium (FIB). Recently, many studies reported that E. coli populations in the environment are affected by ambient environmental conditions affecting their long-term survival. Large-scale studies of population genetics revealed the diversity and complexity of E. coli strains in various environments, which are affected by multiple environmental factors. This review examines the current knowledge on the ecology of E. coli strains in various environments with regard to its role as a FIB and as a naturalized member of indigenous microbial communities. Special emphasis is given on the growth of pathogenic E. coli in the environment, and the population genetics of environmental members of the genus Escherichia. The impact of environmental E. coli on water quality and public health is also discussed. © 2017 The Society for Applied Microbiology.

The use of valinomycin, nigericin and trichlorocarbanilide in control of the protonmotive force in Escherichia coli cells.

OpenAIRE

Ahmed, S; Booth, I R

1983-01-01

Valinomycin, nigericin and trichlorocarbanilide were assessed for their ability to control the protonmotive force in Escherichia coli cells. Valinomycin, at high K+ concentrations, was found to decrease the membrane potential delta phi and indirectly to decrease the pH gradient delta pH. Nigericin was found to have two modes of action. At low concentrations (0.05-2 microM) it carried out K+/H+ exchange and decreased delta pH. At higher concentrations (50 microM) it carried out a K+-dependent ...

Estimating transmission parameters of F4 + E. coli for F4-receptor-positive and -negative piglets: one-to-one transmission experiment

NARCIS (Netherlands)

Geenen, P.L.; Meulen, van der J.; Bouma, A.; Jong, de M.C.M.

2004-01-01

F4+ Escherichia coli is an important agent of post-weaning diarrhoea in piglets. Piglets that express an adhesion site for F4+ E. coli in their small intestine (F4R+) shed higher numbers of F4+ E. coli than piglets lacking this site (F4R[minus sign]). We hypothesized that F4R+ piglets are more

The Prevalence of Enterhaemorrhagic Escherichia Coli in children ...

African Journals Online (AJOL)

EHEC), the pathogenicity of other strains of Escherichia coli and other organisms in children presenting with and without diarrhoea in the hospital. Subjects and Methods: A total of 247 stool samples collected from children aged 1 month to 7 ...

Escherichia coli O157:H7 - An Emerging Pathogen in foods of Animal Origin

Directory of Open Access Journals (Sweden)

Ch. Bindu Kiranmayi

Full Text Available Escherichia coli O157:H7 is an emerging public health concern in most countries of the world. E. coli O157:H7 was known to be a human pathogen for nearly 24 years. EHEC O157 infection is estimated to be the fourth most costly food borne disease in Canada and USA, not counting the cost of possible litigation. E. coli O157:H7 and Salmonella are the leading causes of produce related outbreaks, accounting for 20 and 30% respectively. The authority of the Federal Meat Inspection Act, FSIS (Food Safety and Inspection Service declared Escherichia coli O157:H7, an adulterant in raw ground beef and enforced “zero tolerance” (USDA-FSIS, 17 December 1998. Because of the severity of these illnesses and the apparent low infective dose (less than 10 cells, Escherichia coli O157:H7 is considered one of the most serious of known food borne pathogens. Escherichia coli O157:H7 is mainly pathogenic to human but in cattle and other animals, it did not induce any clinical disease except diarrhea. So, these animals act as carriers to Escherichia coli O157:H7. The majority transmission is through eating of undercooked contaminated ground meat and consumption of raw milk, raw vegetables, fruits contaminated by water, cheese, curd and also through consumption of sprouts, lettuce and juice. The conventional isolation procedure includes growth in enrichment broth like modified EC (E. coli broth or modified tryptic soy broth (mTSB Since the infection primarily occurs via faeco-oral route, the preventive measures include food hygiene measures like proper cooking of meat, consumption of pasteurized milk, washing fruits and vegetables especially those to be eaten raw and drinking chlorine treated water and personnel hygiene measures like washing hands after toilet visits. [Veterinary World 2010; 3(8.000: 382-389

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

Science.gov (United States)

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

Improvements In Ethanologenic Escherichia Coli and Klebsiella Oxytoca

Energy Technology Data Exchange (ETDEWEB)

Dr. David Nunn

2010-09-30

The current Verenium cellulosic ethanol process is based on the dilute-acid pretreatment of a biomass feedstock, followed by a two-stage fermentation of the pentose sugar-containing hydrolysate by a genetically modified ethanologenic Escherichia coli strain and a separate simultaneous saccharification-fermentation (SSF) of the cellulosic fraction by a genetically modified ethanologenic Klebsiella oxytoca strain and a fungal enzyme cocktail. In order to reduce unit operations and produce a fermentation beer with higher ethanol concentrations to reduce distillation costs, we have proposed to develop a simultaneous saccharification co-fermentation (SScF) process, where the fermentation of the pentose-containing hydrolysate and cellulosic fraction occurs within the same fermentation vessel. In order to accomplish this goal, improvements in the ethanologens must be made to address a number of issues that arise, including improved hydrolysate tolerance, co-fermentation of the pentose and hexose sugars and increased ethanol tolerance. Using a variety of approaches, including transcriptomics, strain adaptation, metagenomics and directed evolution, this work describes the efforts of a team of scientists from Verenium, University of Florida, Massachusetts Institute of Technology and Genomatica to improve the E. coli and K. oxytoca ethanologens to meet these requirements.

Escherichia coli promoter sequences predict in vitro RNA polymerase selectivity.

OpenAIRE

Mulligan, M E; Hawley, D K; Entriken, R; McClure, W R

1984-01-01

We describe a simple algorithm for computing a homology score for Escherichia coli promoters based on DNA sequence alone. The homology score was related to 31 values, measured in vitro, of RNA polymerase selectivity, which we define as the product KBk2, the apparent second order rate constant for open complex formation. We found that promoter strength could be predicted to within a factor of +/-4.1 in KBk2 over a range of 10(4) in the same parameter. The quantitative evaluation was linked to ...