Enteropathogenic and enterohaemorrhagic Escherichia coli are related pathotypes of bacteria that cause acute watery diarrhoea and haemorrhagic colitis, respectively, and enterohaemorrhagic E. coli can lead to a serious complication known as haemolytic uraemic syndrome. In both bacteria the global regulatory protein Ler controls virulence. The ler gene is found within the locus of enterocyte effacement, or LEE, encoding a type III secretion system necessary for injecting effector proteins into intestinal epithelial cells and causing net secretory diarrhoea. The nucleoid-associated protein H-NS silences, whereas Ler serves as an anti-silencer of, multiple LEE operons. Although Ler has a higher affinity for DNA than does H-NS, the precise molecular mechanism by which Ler increases LEE transcription remains to be determined. In this report we investigate the oligomerization activity of Ler. In solution, Ler forms dimers and soluble aggregates of up to 5000 kDa molecular mass, and appears to oligomerize more

TY - JOUR. T1 - A gram-negative characteristic segment in Escherichia coli DnaK is essential for the ATP-dependent cooperative function with the co-chaperones DnaJ and GrpE. AU - Sugimoto, Shinya. AU - Higashi, Chihana. AU - Saruwatari, Kozue. AU - Nakayama, Jiro. AU - Sonomoto, Kenji. PY - 2007/6/26. Y1 - 2007/6/26. N2 - We describe importance of the characteristic segment in ATPase domain of DnaK chaperone which is present in all gram-negative bacteria but is absent in all gram-positive bacteria. In vitro studies, ATPase activity, luciferase-refolding activity, and surface plasmon resonance analyses, demonstrated that a segment-deletion mutant DnaKΔ74-96 became defective in the cooperation with the co-chaperones DnaJ and GrpE. In addition, in vivo complementation assay showed that expression of DnaKΔ74-96 could not rescue the viability of Escherichia coli ΔdnaK mutant at 43 °C. Consequently, we suggest evolutionary significance for this DnaK ATPase domain segment in gram-negative bacteria ...

In the study described here, we have taken steps to characterize the YjeE protein, an Escherichia coli protein of unknown function that is essential for bacterial viability. YjeE represents a protein family whose members are broadly conserved in bacteria, absent from eukaryotes and contain both Walker A and B motifs, characteristic of P-loop ATPases. We have revisited the dispensability of the yjeE gene in E. coli and describe efforts to probe the function of the YjeE protein with in vitro biochemistry. We have looked critically for ATPase activity in the recombinant E. coli protein and have made vigilant use of site-directed variants in the Walker A [K41A (Lys41→Ala) and T42A] and putative Walker B (D80Q) motifs. We noted that any hydrolysis of ATP by the wild-type E. coli protein might be attributed to background ATPase, since it was not appreciably different from that of the variants. To overcome potential contaminants, we turned to crystalline pure YjeE protein from Haemophilus influenzae ...

What is Escherichia coli?. Escherichia coli (abbreviated as E. coli) are a large and diverse group of bacteria. Although most strains of E. coli are harmless, others can make you sick. Some kinds of E. coli can cause diarrhea, while others cause urinary tract infections, respiratory illness and pneumonia, and other illnesses. Still other kinds of E. coli are used as markers for water contamination-so you might hear about E. coli being found in drinking water, which are not themselves harmful, but indicate the water is contaminated. It does get a bit confusing-even to microbiologists.. What are Shiga toxin-producing E. coli? Some kinds of E. coli cause disease by making a toxin called Shiga toxin. The bacteria that make these toxins are called Shiga toxin-producing E. coli, or STEC for short. You might hear them called verocytotoxic E. coli (VTEC) or enterohemorrhagic E. coli (EHEC); these all refer generally to the same group of bacteria. The most commonly identified STEC in North America is ...

AEEC - Attaching and Effacing Escherichia Coli. Looking for abbreviations of AEEC? It is Attaching and Effacing Escherichia Coli. Attaching and Effacing Escherichia Coli listed as AEEC

TY - JOUR. T1 - Use of designed metal-binding sites to study helix proximity in the lactose permease of Escherichia coli. 2. Proximity of helix IX (Arg302) with helix X (His322 and Glu325). AU - He, Molly M.. AU - Voss, John C. AU - Hubbell, Wayne L.. AU - Ronald Kaback, H.. PY - 1995. Y1 - 1995. N2 - Engineering divalent metal-binding sites into the lactose permease of Escherichia coli by introducing bis-His residues has been utilized to confirm the proximity of helices VIII (Glu269→His) and X (His322) [Jung, K., Voss, J., He, M., Hubbell, W. L., & Kaback, H. R. (1995) Biochemistry 34, 6272] and helices VII (Asp237→His) and XI (Lys358→His) [He, M. M., Voss, J., Hubbell, W. L., & Kaback, H. R. (1995) Biochemistry 34, 00000-00000]. In this paper, the approach is used to confirm and extend the relationship between helices IX (Arg302) and X (His322 and Glu325) [Jung, K., Jung, H., Wu, J., Prive, G. G., & Kaback, H. R. (1993) Biochemistry 32, 12273]. Thus, mutants Arg302→His, Glu325→His, ...

Base Sequence, Binding Sites, Catalysis, Cations; Divalent, Endoribonucleases/genetics/*metabolism, Escherichia coli/*enzymology, Escherichia coli Proteins, Hydrolysis, Molecular Sequence Data, Nucleic Acid Conformation, RNA; Catalytic/genetics/*metabolism, RNA; Messenger/chemistry/*metabolism, RNA; Transfer/chemistry/metabolism, Ribonuclease P ...

BioAssay record AID 1077160 submitted by ChEMBL: Inhibition of Escherichia coli FabH expressed in Escherichia coli BL21 (DE3) after 25 mins.

[Gastro-hemorrhagic Escherichia coli].: Groups of Escherichia coli enteropathogen are described, with special attention to Escherichia coli enterohaemorragic. S

Escherichia Coli news, clinical research studies and treatment articles dealing with e. coli infections for medical professionals to stay updated. Get our FREE app now.

BACKGROUND: Escherichia coli associated with early-onset sepsis (EOS) have historically been antibiotic-susceptible and K1-encapsulated. In the era of emerging antibiotic resistance, however, the clonal makeup of E coli associated with EOS has not been well characterized. METHODS: Escherichia coli isolates were collected from 28 cases of EOS and early-onset meningitis (EOM)

Escherichia coli ATCC ® 700927D-5™ Designation: Genomic DNA from Escherichia coli strain EDL 933 TypeStrain=False Application:

Escherichia coli ATCC ® 700927D-5™ Designation: Genomic DNA from Escherichia coli strain EDL 933 TypeStrain=False Application:

BioAssay record AID 414701 submitted by ChEMBL: Resistance index, MIC for aminoglycosides-resistant Escherichia coli BL21 harboring pETSACG1 expressing APH(3)-3a enzyme to MIC for Escherichia coli BL21.

The hns gene is a member of the cold-shock regulon, indicating that the nucleoid-associated, DNA-binding protein H-NS plays an important role in the adaptation of Escherichia coli to low temperatures. We show here that the ability to cope efficiently with a cold environment (12 degrees C and 25 degr …

This protocol was developed in a project aimed to identify the inner membrane proteins localizing to cell poles in Escherichia coli (E. coli). By using a known polar protein Tar as a tag, we isolated pole-derived inner membrane vesicles by affinity capture. The specificity of the polar vesicle isolation was confirmed by mass spectrometry that identified more than one hundred proteins, most of which are known inner membrane proteins, including other known polar proteins. This protocol, or if adapted properly by choosing other affinity targets, is well suited to isolate other membrane domains of interest for identification of proteins or lipid composition.

TY - JOUR. T1 - Evaluation of CTX-M steady-state mRNA, mRNA half-life and protein production in various STs of Escherichia coli. AU - Geyer, Chelsie N.. AU - Fowler, Randal C.. AU - Johnson, James R.. AU - Johnston, Brian. AU - Weissman, Scott J.. AU - Hawkey, Peter. AU - Hanson, Nancy D.. PY - 2016/3/1. Y1 - 2016/3/1. N2 - Objectives: High levels of β-lactamase production can impact treatment with a β-lactam/β-lactamase inhibitor combination. Goals of this study were to: (i) compare the mRNA and protein levels of CTX-M-15- and CTX-M-14-producing Escherichia coli from 18 different STs and 10 different phylotypes; (ii) evaluate the mRNA half-lives and establish a role for chromosomal- and/or plasmid-encoded factors; and (iii) evaluate the zones of inhibition for piperacillin/tazobactam and ceftolozane/tazobactam. Methods: Disc diffusion was used to establish zone size. RNA analysis was accomplished using real-time RT-PCR and CTX-M protein levels were evaluated by immunoblotting. Clinical ...

RseB from Escherichia coli has been crystallized and crystal structures were determined at 2.4 Å and at 2.8 Å resolution. The structure of cytoplasmic expressed RseB revealed that it consists of two domains; an N-terminal large and a C-terminal small domain. The large domain resembles an unclosed β-barrel that is structurally remarkably similar to a protein family (LolA, LolB) capable of binding the lipid anchor of lipoproteins. Detailed structural comparison of RseB and LolA led to the hypothesis that RseB might be a sensor for mislocalized lipoproteins. The small C-terminal domain, connected to the large domain by a partially unstructured loop, was identified to mediate interaction with RseA. A peptide comprised of a putative helix of RseA was shown to constitute the binding site for RseB. Structure based results presented in this thesis indicate a new role of RseB in acting as a sensor for periplasmic stress: it detects mislocalized lipoproteins in the periplasm and propagates the signal ...

Escherichia Coli or E. Coli is a bacterium commonly found in the human intestine. These bacteria consist of several types and most of them are harmless. That means that only a handful of types of E. Coli bacteria can harm health. One of the dangerous E. coli bacteria is E. coli O157: H7. These bacteria can cause food poisoning and infections that are quite serious. E. coli O157: H7 can produce poisons that can damage the walls of the small intestine and cause stomach cramps, diarrhea mixed with blood, and vomiting ...

The AcrAB system of Escherichia coli is a multidrug efflux system composed of an RND-type transporter AcrB and a periplasmic accessory protein AcrA, and pumps out a wide variety of lipophilic and amphiphilic inhibitors directly into the medium, presumably through the TolC outer membrane channel. Acr …

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You searched for: Format Text Remove constraint Format: Text Language English Remove constraint Language: English Subject RNA Remove constraint Subject: RNA Subject Escherichia coli Remove constraint Subject: Escherichia coli ...

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The structure of the Escherichia coli chromosome is inherently dynamic over the duration of the cell cycle. Genetic loci undergo both stochastic motion around their initial positions and directed motion to opposite poles of the rod-shaped cell during segregation. We developed a quantitative method to characterize cell-cycle dynamics of the E. coli chromosome to probe the chromosomal steady-state mobility and segregation process. By tracking fluorescently labeled chromosomal loci in thousands of cells throughout the entire cell cycle, our method allows for the statistical analysis of locus position and motion, the step-size distribution for movement during segregation, and the locus drift velocity. The robust statistics of our detailed analysis of the wild-type E. coli nucleoid allow us to observe loci moving toward midcell before segregation occurs, consistent with a replication factory model. Then, as segregation initiates, we perform a detailed characterization of the average segregation velocity of

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The mechanism of transport of KP-736, a novel cephalosporin with a 1,5-dihydroxy-4-pyridone moiety at the C-7 position, into the Escherichia coli K-12 cell was investigated by determining the susceptibilities of iron transport mutants to KP-736. The tonB mutant showed a higher degree of resistance to KP-736, indicating that KP-736 was incorporated into E. coli cells via the tonB-dependent iron transport system. The product of the exbB gene was also necessary for the maximal antibacterial potency of KP-736. Cir-lacking and Fiu-lacking mutants showed a moderate level of resistance to KP-736. However, mutants lacking any one of the proteins FepA, FecA, FhuA, and FhuE did not show any increased resistance to KP-736. Two types of spontaneous mutants (e.g., KT1004 and KT1011) could be isolated from cir and fiu mutants by selection for KP-736 resistance and showed the same level of resistance to KP-736 as a tonB mutant. KT1004 showed tonB phenotypes, resistance to phage phi 80, and loss of FecA, ...

Abstract : Escherichia coli (E. coli) infections are the major health concern, as it causes infections in human mainly in urinarytract, ear, and wound infections. The present study evaluates the impact of biofield energy treatment on E. coli regardingantimicrobial sensitivity assay, biochemical study and biotype number. Four multidrug resistant (MDR) clinical lab isolates (LSs)of E. coli (LS 12, LS 13, LS 42, and LS 51) were taken in two groups i.e. control and treated. After treatment, above mentionedparameter were evaluated on day 10 in control and treated samples using MicroScan Walk-Away® system. The antimicrobialsensitivity assay was reported with 46.67% alteration (14 out of 30 tested antimicrobials) in treated group of MDR E. coli isolates.The minimum inhibitory concentration (MIC) study showed the alteration in MIC values of about 34.37% (11 out of 32) testedantimicrobials, after biofield treatment in clinical isolates of E. coli. Piperacillin/tazobactam was reported with ...

The genes (cps) involved in the synthesis of the colanic acid capsular polysaccharide in Escherichia coli K-12 are transcriptionally regulated by numerous proteins. Two of these, RcsB and RcsC, share homology with two-component regulatory elements that respond to environmental stimuli. Osmotic shock by sucrose or NaCl transiently increased transcription of a cpsB::lacZ fusion. RcsC and RcsB were essential for osmotic induction of colanic acid synthesis. In contrast to observations in some other osmotically regulated systems, addition of glycine betaine enhanced the osmotic induction of cps::lacZ by both sucrose and NaCl but had no effect alone. ...

Inhibition of disulfide bond formation in Escherichia coli implicates an intricate collaboration of proteins which comprise the glutathione and thioredoxin reducing pathways. Bioengineers have successfully engineered E. coli possessing mutated reducing pathways that promote, rather than inhibit, disulfide bond formation in the cytoplasm. The transcriptome of six such mutant E. coli strains have been characterized using Microarray technology. We find that all mutant strains, exhibit a unique response to oxidative stress, not observed in wild type. Statistical analyses revealed the expression of more than 200 genes that are affected by mutations within the reducing pathways. Significantly up-regulated biological processes include cysteine biosynthesis, histidine biosynthesis, NADH Dehydrogenase I biosynthesis, sugar catabolic processes, and activation of stress responses . The second part of this work describes the construction of an E. coli strain that promotes the complete conversion of ...

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Nucleotide sequences of translated regions of the trp operon in 12 wild strains of Escherichia coli reveal striking uniformity among eight strains (suggesting recent common ancestry and supporting the importance of periodic selection in natural populations) and clustered substitutions in four strains (implicating events affecting runs of nucleotides).

The ability of salt to rescue division in an FtsEX null mutant is enigmatic if FtsEX is needed for proper assembly or stability of the septal ring. Presumably, the downstream essential division proteins, FtsK through FtsN, all of which are required for division even on media containing salt, have some ability to localize in the absence of FtsEX. Consistent with this, RG60 is sensitive to β-lactams that target FtsI (D. Weiss, unpublished data) and we observed localization of FtsN, which is a late recruit to the division site (1), when RG60 was grown under permissive conditions. It is tempting to speculate that the ability of downstream proteins to localize independently of FtsEX is why we observed some residual localization of FtsK, FtsQ, and FtsI in filaments depleted of FtsEX in LB with no salt, but we cannot exclude the less interesting possibility that there is residual FtsEX in these filaments. Our depletion strains express ftsEX from a multicopy plasmid, so we sought to reduce the ...

Slipped-strand mispairing (SSM) has not been identified as a mechanism of phase variation in Escherichia coli. Using a reporter gene, we show that sequences that cause phase variation by SSM in Haemophilus influenzae also lead to phase variation when introduced onto the chromosome of E. coli, and the frequencies of switching are in the biologically relevant range. Thus, the absence of SSM-mediated phase variation in E. coli does not appear to be due to a mechanistic constraint. ...

The bacterium Escherichia coli is making rounds around the world. The bacteria, previously considered far less harmeless has come under in recent months. To be fair, most of the bacteria is commonly found among humans and animals alike. However, its contact with people with antibacterial resistance can lead to severe illnesses. These include cases of blood poisoning or even resulting in septic shocks. The recent breakout of these illnesses due to anti-bacterial resistance lead researchers to look a bit closer. The outbreak of E.Coli happens as some people may eat bad case of raw meat or a poor personal hygiene. If one doesnt wash his hands after visiting a restroom, they are more likely to be at risk from possible infections. This lead scientists to ask which one is more dangerous as a source of infection. Researchers from University of East Anglia in United Kingdom started this discovery on an unclear note. They were puzzled as the healthy bacteria lives in the intestine of most individuals. ...

SUMMARY: Four mutants of Escherichia coli K12 were isolated on the basis of their sensitivity to pH 5.4. Under non-permissive conditions their growth was reversibly inhibited. At pH 7.0 these mutants showed a highly pleiotropic phenotype, which included altered phage and detergent sensitivities and leakage of periplasmic proteins. The findings suggest a defect in the outer membrane, perhaps in lipopolysaccharide. Two mutants mapped in or near the rfa locus, while the other two were remote from this region.

Birkenbihl, R.P.; Vielmetter, W., 1989: Cosmid derived map of escherichia coli strain bhb2600 in comparison to the map of strain w3110

Bekijk Stockfoto van Escherichia Coli Cell With Disrupted Cell Envelope Due To Phage Release After The Phage Replicate Within Host Cells They Must Be Released From The Host Cell This Often Occurs By Lysing The Cell Sem X3500. Ga voor hoogwaardige fotos met een hoge resolutie naar Getty Images.

The Ffh-4.5S ribonucleoprotein particle (RNP) and FtsY from Escherichia coli are homologous to essential components of the mammalian signal recognition particle (SRP) and SRP receptor, respectively. The ability of these E. coli components to function in a bona fide co-translational targeting pathway remains unclear. Here we demonstrate that the Ffh-4.5S RNP and FtsY can efficiently replace their mammalian counterparts in targeting nascent secretory proteins to microsomal membranes in vitro. Targeting in the heterologous system requires a hydrophobic signal sequence, utilizes GTP and, moreover, occurs co-translationally. Unlike mammalian SRP, however, the Ffh-4.5S RNP is unable to arrest translational elongation, which results in a narrow time window for the ribosome nascent chain to interact productively with the membrane-bound translocation machinery. The highly negatively charged N-terminal domain of FtsY, which is a conserved feature among prokaryotic SRP receptor homologs, is important for ...

Synonyms for Escherichia coli infections in Free Thesaurus. Antonyms for Escherichia coli infections. 1 synonym for Escherichia coli: E. coli. What are synonyms for Escherichia coli infections?

How is Defective DNA of the Bacteria Escherichia Coli abbreviated? DNAa stands for Defective DNA of the Bacteria Escherichia Coli. DNAa is defined as Defective DNA of the Bacteria Escherichia Coli very rarely.

The intimin gene eae, located within the locus of enterocyte effacement pathogenicity island, distinguishes enteropathogenic Escherichia coli (EPEC) and some Shiga toxin-producing E. coli (STEC) strains from all other pathotypes of diarrheagenic E. coli. EPEC is a leading cause of infantile diarrhea in developing countries, and intimin-positive STEC isolates are typically associated with life-threatening diseases such as hemolytic-uremic syndrome and hemorrhagic colitis. Here we describe the development of a PCR-restriction fragment length polymorphism (RFLP) assay that reliably differentiates all 11 known intimin types (α1, α2, β, γ, κ, ɛ, η, ι, λ, θ, and ζ) and three new intimin genes that show less than 95% nucleotide sequence identity with existing intimin types. We designated these new intimin genes Int-μ, Int-ν, and Int-ξ. The PCR-RFLP assay was used to screen 213 eae-positive E. coli isolates derived from ovine, bovine, and human sources comprising 60 serotypes. Of these, 82 were

Abstract: This work reports for the first on the prevalence of Escherichia coli and Salmonella spp. in beef sold in the Tamale Metropolis. The conventional method was used to isolate Escherichia coli and Salmonella spp. from beef samples sold at the Tamale Metropolis. Seventy beef samples were obtained from seven different locations where meat is popularly sold in the Tamale Metropolis and analyzed microbiologically for Escherichia coli and Salmonella spp. by following procedures in the Bacteriological Analytical Manuel of the FDA-USA. The average prevalence of Escherichia coli was 56% and was highest in Location G (100%), followed by Location C (80%), Locations D and F (60%), Location B (50%) and Location E (40%). Escherichia coli was not isolated from Location A. The overall prevalence of Salmonella spp. in the beef samples was 31%. The location with the highest prevalence of Salmonella spp. was Location F (90%), followed by Location D (50%), Location E (30%) and Location C (20%). Locations A, ...

Enteropathogenic E. coli (EPEC) and enterohemorrhagic E. coli (EHEC) are closely related pathogenic strains of Escherichia coli. The hallmark of EPEC/EHEC infections [DS:H00278 H00277] is induction of attaching and effacing (A/E) lesions that damage intestinal epithelial cells. The capacity to form A/E lesions is encoded mainly by the locus of enterocyte effacement (LEE) pathogenicity island. Tir, Map, EspF, EspG are known LEE-encoded effector proteins secreted via the type III secretion system, which is also LEE-encoded, into the host cell. EPEC and EHEC Tirs link the extracellular bacterium to the cell cytoskeleton. Map and EspF are involved in mitochondrion membrane permeabilization. EspG interacts with tubulins and stimulates microtubule destabilization. LEE-encoded adhesin or intimin (Eae) is exported via the general secretory pathway to the periplasm, where it is inserted into the outer membrane. In addition to Tir, two potential host cell-carried intimin receptors, beta1 integrin (ITGB1) ...

Enteropathogenic E. coli (EPEC) and enterohemorrhagic E. coli (EHEC) are closely related pathogenic strains of Escherichia coli. The hallmark of EPEC/EHEC infections [DS:H00278 H00277] is induction of attaching and effacing (A/E) lesions that damage intestinal epithelial cells. The capacity to form A/E lesions is encoded mainly by the locus of enterocyte effacement (LEE) pathogenicity island. Tir, Map, EspF, EspG are known LEE-encoded effector proteins secreted via the type III secretion system, which is also LEE-encoded, into the host cell. EPEC and EHEC Tirs link the extracellular bacterium to the cell cytoskeleton. Map and EspF are involved in mitochondrion membrane permeabilization. EspG interacts with tubulins and stimulates microtubule destabilization. LEE-encoded adhesin or intimin (Eae) is exported via the general secretory pathway to the periplasm, where it is inserted into the outer membrane. In addition to Tir, two potential host cell-carried intimin receptors, beta1 integrin (ITGB1) ...

Looking for Escherichia coli infections? Find out information about Escherichia coli infections. common bacterium that normally inhabits the intestinal tracts of humans and animals, but can cause infection in other parts of the body, especially the... Explanation of Escherichia coli infections

Pathogenic Escherichia coli are known to be a common cause of diarrheal disease - a common cause of frequently occurring bacterial infections in children and adults in developing countries. It poses a significant problem in Latin America. Pathogenic Escherichia coli in Latin America presents current information on understanding pathogenic E. coli in Latin America and outlines prospects for future research in this region. It features a unique, comprehensive analysis of the most common categories of E. coli associated with diarrheal illness in Latin America. The aim of this book is to help epidemiologists in this region to learn about molecular mechanisms of E. coli pathogenesis along with its diagnosis, host immune responses, animal reservoirs and epidemiology. In addition, the authors discuss the current situation of E. coli in representative countries, including Argentina, Brazil, Chile, Mexico and Peru ...

Escherichia coli α-hemolysin (HlyA) is a pore-forming protein of 110 kDa belonging to the family of RTX toxins. A hydrophobic region between the amino acid residues 238 and 410 in the N-terminal half of HlyA has previously been suggested to form hydrophobic and/or amphipathic α-helices and has been shown to be important for hemolytic activity and pore formation in biological and artificial membranes. The structure of the HlyA transmembrane channel is, however, largely unknown. For further investigation of the channel structure, we deleted in HlyA different stretches of amino acids that could form amphipathic β-strands according to secondary structure predictions (residues 71-110, 158-167, 180-203, and 264-286). These deletions resulted in HlyA mutants with strongly reduced hemolytic activity. Lipid bilayer measurements demonstrated that HlyAΔ71-110 and HlyAΔ264-286 formed channels with much smaller single-channel conductance than wildtype HlyA, whereas their channel-forming activity was virtually

TY - JOUR. T1 - The structure of Escherichia coli heat‐stable enterotoxin b by nuclear magnetic resonance and circular dichroism. AU - Sukumar, M.. AU - Rizo-Rey, Jose. AU - Wall, M.. AU - Dreyfus, L. A.. AU - Kupersztoch, Y. M.. AU - Gierasch, L. M.. PY - 1995/9. Y1 - 1995/9. N2 - The heat‐stable enterotoxin b (STb) is secreted by enterotoxigenic Escherichia coli that cause secretory diarrhea in animals and humans. It is a 48‐amino acid peptide containing two disulfide bridges, between residues 10 and 48 and 21 and 36, which are crucial for its biological activity. Here, we report the solution structure of STb determined by two‐ and three‐dimensional NMR methods. Approximate interproton distances derived from NOE data were used to construct structures of STb using distance‐geometry and simulated annealing procedures. The NMR‐derived structure shows that STb is helical between residues 10 and 22 and residues 38 and 44. The helical structure in the region 10-22 is amphipathic and ...

Volunteer studies have shown that a 60-megadalton plasmid is required for full virulence of the human enteropathogenic Escherichia coli (EPEC) strain E2348/69 (O127:H6). The plasmid, designated pMAR2, encodes localized adherence to HEp-2 cells in tissue culture via the adhesin known as the EPEC adherence factor (EAF). Using a DNA probe for the EAF, we have previously shown that these genes are specific for EPEC and are usually encoded on plasmids ranging from 55 to 65 megadaltons. In this study, Southern blot analysis and S1 nuclease homology determination reveal a high degree of sequence conservation among these plasmids, despite some variation in restriction maps. Phenotypic characterization of the prototype EAF plasmid pMAR2 reveals that the plasmid belongs to the group IncFII and is negative for alpha-hemolysin, colicin, and aerobactin synthesis, as well as biochemical markers and antibiotic resistance. Regions encoding adherence to HEp-2 cells were localized by Tn801 insertion mutagenesis. ...

FtsA is an essential cell division protein which is synthesized in minute amounts in Escherichia coli. To study the effects of overexpressing ftsA on the phenotype of E. coli cells, DNA fragments encoding the ftsA gene were subcloned downstream of a lac or a tac promoter in two plasmids. High-level expression of the ftsA gene from these promoters inhibited normal cell septation and caused the cells to become long, nonseptate filaments. Continued overexpression of ftsA resulted in the filaments developing spherical bulges up to 4 um in diameter. It is suggested that these bulges may emanate from septation sites because they were evenly spaced in relation to one another and to the cell poles. Observations of thin sections by electron microscopy demonstrated that these bulges contained small electron dense regions and large electron-lucent plate-like inclusions. A finding that the bulging filamentous cells contain more hexosamine per mass than control cells suggests that abnormal peptidoglycan synthesis

Diarrhea caused by Escherichia coli that produce only heat-stable enterotoxin.: To determine the role of Escherichia coli heat-stable enterotoxin (ST) as a viru

ABSTRACT. Costa K.O., Alzamora Filho F., Costa J.N., Amorim C.R.N.,Yano T. & Conceição R.A. [Virulence factors of Escherichia coli isolated from calves with diarrhea in the region of Feira de Santana, Bahia.] Fatores de virulência das amostras de Escherichia coli isoladas de bezerros com diarreia na região de Feira de Santana, Bahia. Revista Brasileira de Medicina Veterinária, 36(4):430-436, 2014. Departamento de Ciências Biológicas, Universidade Estadual de Feira de Santana, BR 116 norte, Km 3, Feira de Santana, BA 44032-560, Brasil. E-mail: [email protected] Escherichia coli is a Gram-negative bacterium most commonly isolated from intra and extraintestinal infections in both man and in other animals such as pigs and calves. Six distinct groups of E. coli can be identified by the type of toxin and the clinical signals they produce. Among these, E. coli enterotoxigenic (ETEC) is the most commonly found and produces two types of toxin: heat-labile (LT-I and LT-II) and heat-stable (STa and ...

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

Looking for Escherichia coli enteritis? Find out information about Escherichia coli enteritis. common bacterium that normally inhabits the intestinal tracts of humans and animals, but can cause infection in other parts of the body, especially the... Explanation of Escherichia coli enteritis

REFERENCES. ANDRADE, G. I. et al. Identification of virulence factors by multiplex PCR in Escherichia coli isolated from calves in Minas Gerais, Brazil. Tropical Animal Health and Production, v.44, n.7, p.1783-1790, 2012. Available from: ,Available from: http://www.ncbi.nlm.nih.gov/pubmed/22476791 ,. Accessed: Nov. 20, 2013. doi: 10.1007/s11250-012-0139-8. [ Links ] BALDY-CHUDZIK, K. et al. Phylogenetic background, virulence gene profiles, and genomic diversity in commensal Escherichia coli isolated from ten mammal species living in one zoo. Veterinary Microbiology, v.131, n.1-2, p.173-184, 2008. Available from: ,Available from: https://www.ncbi.nlm.nih.gov/pubmed/18423907 ,. Accessed: Nov. 20, 2013. doi: 10.1016/j.vetmic.2008.02.019. [ Links ] BERALDO, L. G. et al. Detection of Shiga toxigenic (STEC) and enteropathogenic (EPEC) Escherichia coli in dairy buffalo. Veterinary Microbiology, v.170, n.1-2, p.162-166, 2014. Available from: ,Available from: https://www.ncbi.nlm.nih.gov/pubmed/24560591 ...

TY - JOUR. T1 - Genotipificación, evaluación toxigénica in vitro y sensibilidad a antibióticos de cepas de escherichia coli aisladas de casos diarreicos y fatales en alpacas neonatas. AU - Luna, E. Luis. AU - Maturrano, H. Lenin. AU - Rivera Geronimo, Hermelinda. AU - Zanabria, H. Víctor. AU - Rosadio, A. Raúl. N1 - Copyright: Copyright 2020 Elsevier B.V., All rights reserved.. PY - 2012/8. Y1 - 2012/8. N2 - Clinical rectal diarrheic swabs (n=27) and pathological intestinal contents (n=24) from 51 alpacas between 1 to 7 weeks of age were used to isolate and genotype Escherichia coli, and to test for antimicrobial sensibility. All the E. coli isolates, confirmed by the API system, were genotyped by Multiplex PCR to determine the presence of virulence genes: stx1 and stx2 (shigatoxin 1 and 2), eae (intimin), bfp (Bundle-Forming Pili), lt (heat-labile toxin), sta and stb (heat-stable toxin A and B), in enterohemorrhagic (EHEC), enteropathogenic (EPEC) or enterotoxigenic (ETEC) E. coli ...

No presente estudo, 47 amostras enteropatogênicas de Escherichia coli, previamente caracterizadas pelo sorotipo, fenótipo de aderência, habilidade de induzir a formação da lesão histopatológica e presença das seqüências genéticas eae, bfp e EAF, foram analisadas de acordo com o perfil de fragmentação do DNA cromossômico pela técnica de eletroforese em campo pulsado (PFGE), as variantes isoenzimáticas através da eletroforese de isoenzimas (MLEE) e a presença de seqüências específicas da região LEE (eae, espA, espB, tir) e respectivos alelos. A amplificação destas seqüências mostrou a presença de 18 padrões genéticos distintos. A tipagem do gene eae revelou que a maior parte das amostras apresentou intimina não-tipável (42%) seguida dos tipos alélicos beta (35%), gama e alfa (12% cada). A fragmentação do DNA cromossômico detectou um elevado polimorfismo genético entre as amostras estudadas e não foi observada uma correlação com os marcadores de virulência ...

Attaching and effacing (A/E) intestinal lesions are produced by enteropathogenic Escherichia coli (EPEC), enterohemorrhagic E. coli (EHEC), and RDEC-1, a pathogen of weanling rabbits. We recently identified a chromosomal locus (eae[E. coli A/E]) which is required for A/E activity in a wild-type EPEC strain. Sequences homologous to those of an eae gene probe were detected in EPEC, RDEC-1, and EHEC isolates. We report here that the eae gene is chromosomally encoded in all EPEC and EHEC strains tested and in RDEC-1. In addition, the eae probe was found to be 100% sensitive and 98% specific in detecting E. coli of EPEC serogroups that demonstrate A/E activity. Ten percent of E. coli of EPEC serogroups that hybridized with the eae probe and produced A/E activity did not hybridize with the EAF (EPEC adherence factor) probe, a plasmid-associated diagnostic probe which is currently used to identify EPEC. In addition to A/E factors, plasmid-associated adhesins also contribute to the pathogenesis of EPEC ...

Summary Strains of Escherichia coli from sporadic cases of diarrhoea and belonging to serotypes O44:H18, O55:H7, O111ab:H21 O111ab:H25 or O126:H25 or O126:H27 were examined for virulence properties. With the exception of O111ab:H25 these are considered to be classical enteropathogenic E. coli (EPEC) serotypes. The strains had been isolated in Britain from the faeces of children |3 years old. Of the serotypes examined, 7 of 13 O44:H18 strains, all of 10 O111ab:H21 strains and 13 of 21 O126:H27 strains belonged to the enteroaggregative class of E. coli (EAggEC) that attached to HEp-2 cells in the characteristic aggregative pattern and hybridised with the EAggEC probe. They also caused mannose-resistant haemagglutination of rat erythrocytes, a property which may be a useful marker for their identification. Strains of O44:H18 with similar properties were also isolated from three small outbreaks in Britain, one of which involved elderly patients. EAggEC have not been considered previously as aetiological

TY - JOUR. T1 - Draft genome sequences of Escherichia coli strains isolated from septic patients. AU - Dunitz, Madison I.. AU - Coil, David A.. AU - Jospin, Guillaume. AU - Eisen, Jonathan A. AU - Adams, Jason Yeates. PY - 2014. Y1 - 2014. N2 - We present the draft genome sequences of six strains of Escherichia coli isolated from blood cultures collected from patients with sepsis. The strains were collected from two patient sets, those with a high severity of illness, and those with a low severity of illness. Each genome was sequenced by both Illumina and PacBio for comparison.. AB - We present the draft genome sequences of six strains of Escherichia coli isolated from blood cultures collected from patients with sepsis. The strains were collected from two patient sets, those with a high severity of illness, and those with a low severity of illness. Each genome was sequenced by both Illumina and PacBio for comparison.. UR - ...

TY - JOUR. T1 - Recovery of YAC-end sequences through complementation of an Escherichia coli pyrF mutation. AU - Wright, David A.. AU - Park, Sei Kyoung. AU - Wu, Dongying. AU - Phillips, Gregory J.. AU - Rodermel, Steven R.. AU - Voytas, Daniel F.. PY - 1997/7/1. Y1 - 1997/7/1. N2 - We have developed a genetic means to recover sequences from YAC-ends near the yeast selectable marker URA3. This strategy is based on the ability of URA3 to complement mutations in pyrF, an Escherichia coli gene required for pyrimidine biosynthesis. We have developed an E. coli strain with a non-reverting allele of pyrF that is also suitable for cloning (recA-, hsdR-). We demonstrate the utility of this complementation strategy to obtain right-end clones from three YACs containing Arabidopsis thaliana DNA.. AB - We have developed a genetic means to recover sequences from YAC-ends near the yeast selectable marker URA3. This strategy is based on the ability of URA3 to complement mutations in pyrF, an Escherichia coli ...

α-helical membrane proteins constitute 20-30% of all proteins in a cell and are involved in many essential cellular functions. The structure is only known for a few hundred of them, which makes structural models important. The most common structural model of a membrane protein is the topology which is a two-dimensional representation of the structure.. This thesis is focused on three different aspects of membrane protein structure: improving structural predictions of membrane proteins, improving the level of detail of structural models and the concept of dual topology.. It is possible to improve topology models of membrane proteins by including experimental information in computer predictions. This was first performed in Escherichia coli and, by using homology, it was possible to extend the results to 225 prokaryotic organisms. The improved models covered ~80% of the membrane proteins in E. coli and ~30% of other prokaryotic organisms.. However, the traditional topology concept is sometimes too ...

Eenteropathogenic E. coli (EPEC) and enterohemorrhagic E. coli (EHEC) are closely related pathogenic strains of Escherichia coli. The hallmark of EPEC/EHEC infections is induction of attaching and effacing (A/E) lesions that damage intestinal epithelial cells. The capacity to form A/E lesions is encoded mainly by the locus of enterocyte effacement (LEE) pathogenicity island. Tir, Map, EspF, EspG are known LEE-encoded effector proteins secreted via the type III secretion system, which is also LEE-encoded, into the host cell. EPEC and EHEC Tirs link the extracellular bacterium to the cell cytoskeleton. Map and EspF are involved in mitochondrion membrane permeabilization. EspG interacts with tubulins and stimulates microtubule destabilization. LEE-encoded adhesin or intimin (Eae) is exported via the general secretory pathway to the periplasm, where it is inserted into the outer membrane. In addition to Tir, two potential host cell-carried intimin receptors, beta1 integrin (ITGB1) and nucleolin ...

LAMPRECHT, Corne et al. Escherichia coli with virulence factors and multidrug resistance in the Plankenburg River. S. Afr. j. sci. [online]. 2014, vol.110, n.9-10, pp.01-06. ISSN 1996-7489. http://dx.doi.org/10.1590/sajs.2014/20130347.. Escherichia coli is a natural inhabitant of the gut and E. coli levels in water are considered internationally to be an indication of faecal contamination. Although not usually pathogenic, E. coli has been linked to numerous foodborne disease outbreaks, especially those associated with fresh produce. One of the most common ways through which E. coli can be transferred onto fresh produce is if contaminated water is used for irrigation. In this study, a total of 81 confirmed E. coli strains were isolated from the Plankenburg River as part of three separate studies over 3 years. During sampling, E. coli levels in the river were above the accepted levels set by the World Health Organization and the South African Department of Water Affairs and Forestry for safe ...

DksA is a global regulatory protein that, together with the alarmone ppGpp, is required for the stringent response to nutrient starvation in the gammaproteobacterium Escherichia coli and for more moderate shifts between growth conditions. DksA modulates the expression of hundreds of genes, directly or indirectly. Mutants lacking a DksA homolog exhibit pleiotropic phenotypes in other gammaproteobacteria as well. Here we analyzed the DksA homolog RSP2654 in the more distantly related Rhodobacter sphaeroides, an alphaproteobacterium. RSP2654 is 42% identical and similar in length to E. coli DksA but lacks the Zn finger motif of the E. coli DksA globular domain. Deletion of the RSP2654 gene results in defects in photosynthetic growth, impaired utilization of amino acids, and an increase in fatty acid content. RSP2654 complements the growth and regulatory defects of an E. coli strain lacking the dksA gene and modulates transcription in vitro with E. coli RNA polymerase (RNAP) similarly to E. coli ...

TY - JOUR. T1 - Development of glycerol-utilizing Escherichia coli strain for the production of bioethanol. AU - Thapa, Laxmi Prasad. AU - Lee, Sang Jun. AU - Yoo, Hah Young. AU - Choi, Han Suk. AU - Park, Chulhwan. AU - Kim, Seung Wook. PY - 2013/8/15. Y1 - 2013/8/15. N2 - production of bioethanol was studied using recombinant Escherichia coli with glycerol as a carbon source. Glycerol is an attractive feedstock for biofuels production since it is generated as a major byproduct in biodiesel industry; therefore, we investigated the conversion of glycerol to bioethanol using E. coli BL21 (DE3) which harbors several genes in ethanol production pathway of Enterobacter aerogenes KCTC 2190. Fermentation was carried out at 34 °C for 42. h, pH 7.6, using defined production medium. Under optimal conditions, bioethanol production by the recombinant E. coli BL21 (DE3), strain pEB, was two-fold (3.01. g/L) greater than that (1.45. g/L) by the wild-type counterpart. The results obtained in this study will ...

TY - JOUR. T1 - An nad synthetic reaction bypasses the lipoate requirement for aerobic growth of Escherichia coli strains blocked in succinate catabolism. AU - Hermes, Fatemah A.. AU - Cronan, John E.. PY - 2014/12/1. Y1 - 2014/12/1. N2 - The lipoate coenzyme is essential for function of the pyruvate (PDH) and 2-oxoglutarate (OGDH) dehydrogenases and thus for aerobic growth of Escherichia coli. LipB catalyzes the first step in lipoate synthesis, transfer of an octanoyl moiety from the fatty acid synthetic intermediate, octanoyl-ACP, to PDH and OGDH. E. coli also encodes LplA, a ligase that in presence of exogenous octanoate (or lipoate) can bypass loss of LipB. LplA imparts ΔlipB strains with a leaky growth phenotype on aerobic glucose minimal medium supplemented with succinate (which bypasses the OGDH-catalyzed reaction), because it scavenges an endogenous octanoate pool to activate PDH. Here we characterize a ΔlipB suppressor strain that did not require succinate supplementation, but did ...

RecA is important for recombination, DNA repair, and SOS induction. In Escherichia coli, RecBCD, RecFOR, and RecJQ prepare DNA substrates onto which RecA binds. UvrD is a 3-to-5 helicase that participates in methyl-directed mismatch repair and nucleotide excision repair. uvrD deletion mutants are sensitive to UV irradiation, hypermutable, and hyper-rec. In vitro, UvrD can dissociate RecA from single-stranded DNA. Other experiments suggest that UvrD removes RecA from DNA where it promotes unproductive reactions. To test if UvrD limits the number and/or the size of RecA-DNA structures in vivo, an uvrD mutation was combined with recA-gfp. This recA allele allows the number of RecA structures and the amount of RecA at these structures to be assayed in living cells. uvrD mutants show a threefold increase in the number of RecA-GFP foci, and these foci are, on average, nearly twofold higher in relative intensity. The increased number of RecA-green fluorescent protein foci in the uvrD mutant is ...

Escherichia coli Hsp31, encoded by hchA, is a heat-inducible molecular chaperone. We found that Hsp31 undergoes a conformational change via temperature-induced unfolding, generating a high molecular weight (HMW) form with enhanced chaperone activity. Although it has previously been reported that some subunits of the Hsp31 crystal structure show structural heterogeneity with increased hydrophobic surfaces, Hsp31 basically forms a dimer. We found that a C-terminal deletion (C Delta 19) of Hsp31 exhibited structurally and functionally similar characteristics to that of the HMW form. Both the C Delta 19 and HMW forms achieved a structure with considerably more p-sheets and less a-helices than the native dimeric form, exposing a portion of its hydrophobic surfaces. The structural alterations were determined from its spectral changes in circular dichroism, intrinsic fluorescence of tryptophan residues, and fluorescence of bis-ANS binding to a hydrophobic surface. Interestingly, during thermal ...

Principal Investigator：SUGAI Motoyuki, Project Period (FY)：1997 - 1998, Research Category：Grant-in-Aid for Scientific Research (C), Section：一般, Research Field：Bacteriology (including Mycology)

The Tat system transports folded proteins across the bacterial cytoplasmic membrane and the thylakoid membrane of plant chloroplasts. Substrates are targeted to the Tat pathway by signal peptides containing a pair of consecutive arginine residues. The membrane proteins TatA, TatB and TatC are the essential components of this pathway in Escherichia coli. The complexes that these proteins form at native levels of expression have been investigated by the use of affinity tag-coding sequences fused to chromosomal tat genes. Distinct TatA and TatBC complexes were identified using size-exclusion chromatography and shown to have apparent molecular masses of approximately 700 and 500 kDa, respectively. Following in vivo expression, the Tat substrate protein SufI was found to copurify with the TatBC, but not the TatA, complex. This binding required the SufI signal peptide. Substitution of the twin-arginine residues in the SufI signal peptide by either twin lysine or twin alanine residues abolished export. However

Attaching and effacing (AE) adhesion is associated with the pathogenesis of enteropathogenic Escherichia coli (EPEC) and rabbit diarrheogenic E. coli (RDEC-1). Although RDEC-1 provides an animal model for investigating pathophysiology of EPEC infection, RDEC-1 does not adhere to human cell lines, thereby limiting in vitro investigation. Therefore, transformed RDEC-1 strains expressing adhesins derived from human diarrheogenic E. coli were studied. These adhesins promoted AE adhesion of RDEC-1 and led to the accumulation of alpha-actinin aggregates in the cytoplasm of infected cells. Furthermore, these strains induced host signal transduction pathways, resulting in tyrosine phosphorylation of host proteins and an intracellular elevation of calcium. These results demonstrate that RDEC-1 and EPEC stimulate similar signal transduction pathways in infected epithelial cells, thus lending additional support for the use of RDEC-1 as a model for the study of human EPEC infection.

TY - JOUR. T1 - Effect of the ε-subunit on nucleotide binding to Escherichia coli F1- ATPase catalytic sites. AU - Weber, Joachim. AU - Dunn, Stanley D.. AU - Senior, Alan E.. PY - 1999/7/2. Y1 - 1999/7/2. N2 - The influence of the ε-subunit on the nucleotide binding affinities of the three catalytic sites of Escherichia coli F1-ATPase was investigated, using a genetically engineered Trp probe in the adenine-binding subdomain (β-Trp-331). The interaction between ε and F1 was not affected by the mutation. K(d) for binding of ε to βY331W mutant F1 was ~1 nM, and ε inhibited ATPase activity by 90%. The only nucleotide binding affinities that showed significant differences in the ε-depleted and ε-replete forms of the enzyme were those for MgATP and MgADP at the high-affinity catalytic site 1. K(d1)(MgATP) and K(d1)(MgADP) were an order of magnitude higher in the absence of ε than in its presence. In contrast, the binding affinities for MgATP and MgADP at sites 2 and 3 were similar in the ...

TY - JOUR. T1 - Phosphoryl transfer from α-D-glucose 1-phosphate catalyzed by Escherichia coli sugar-phosphate phosphatases of two protein superfamily types. AU - Wildberger, Patricia. AU - Pfeiffer, Martin. AU - Brecker, Lothar. AU - Rechberger, Gerald N.. AU - Birner-Gruenberger, Ruth. AU - Nidetzky, Bernd. PY - 2015. Y1 - 2015. N2 - The Cori ester α-D-glucose 1-phosphate (αGlc 1-P) is a high-energy intermediate of cellular carbohydrate metabolism. Its glycosidic phosphomonoester moiety primes αGlc 1-P for flexible exploitation in glucosyl and phosphoryl transfer reactions. Two structurally and mechanistically distinct sugar-phosphate phosphatases from Escherichia coli were characterized in this study for utilization of αGlc 1-P as a phosphoryl donor substrate. The agp gene encodes a periplasmic αGlc 1-P phosphatase (Agp) belonging to the histidine acid phosphatase family. Had13 is from the haloacid dehydrogenase-like phosphatase family. Cytoplasmic expression of Agp (in E. coli Origami ...

Introduction. Escherichia coli, better known as E. coli, are Gram negative, rod-shaped bacteria belonging to the family Enterobacteriaceae. Escherichia species are also included in the group of genera referred to as the coliforms.. Not all E. coli cause disease: the species is found as part of the normal, healthy human gut flora as well as in the environment. Therefore the presence of E. coli in processed food products can indicate faecal contamination. For this reason E. coli is widely used as an indicator organism for the presence of potentially more dangerous bacteria, such as Salmonella.. Although most strains of E. coli do not cause illness, some have been associated with human infections resulting in diarrhoea, or occasionally more severe illness. There are at least six different groups of diarrhoea-causing E. coli, but only two types are associated with foodborne disease.. 1. Verocytotoxin-producing (VTEC), sometimes referred to as Shiga-like toxin-producing (STEC). This group includes ...

Escherichia coli (/ˌɛʃəˈrɪkiə ˈkoʊlɪ/ Anglicized to /ˌɛʃəˈrɪkiə ˈkoʊlaɪ/; commonly abbreviated E. coli) is a gram-negative, rod-shaped bacterium that is commonly found in the lower intestine of warm-blooded organisms (endotherms). Most E. coli strains are harmless, but some serotypes are pathogenic and can cause serious food poisoning in humans, and are occasionally responsible for product recalls. E. coli are also responsible for a majority of cases of urinary tract infections. The harmless strains are part of the normal flora of the gut, and can benefit their hosts by producing vitamin K2, and by preventing the establishment of pathogenic bacteria within the intestine. E. coli and related bacteria constitute about 0.1% of gut flora, and fecal-oral transmission is the major route through which pathogenic strains of the bacterium cause disease. Cells are able to survive outside the body for a limited amount of time, which makes them ideal indicator organisms to test ...

in Advances in Experimental Medicine and Biology (1999), 473. Enteropathogenic Escherichia coli (EPEC) produce attaching and effacing lesions. The genes responsible for this lesion are clustered on the chromosome forming a 35.5 kilobase pathogenesis island called ... [more ▼]. Enteropathogenic Escherichia coli (EPEC) produce attaching and effacing lesions. The genes responsible for this lesion are clustered on the chromosome forming a 35.5 kilobase pathogenesis island called LEE. The LEE was identified, characterized and completely sequenced from the human EPEC strain E2348/69. The LEE carries genes coding for: a type III secretion system (genes esc and sep), the translocated intimin receptor (gene tir), the outer membrane protein intimin (gene eae) and the E. coli secreted proteins EspA, EspB, and EspD (genes esp). In addition to man and farm animals, EPEC are also isolated from dogs and cats. We studied structurally and functionally the LEE of dog and cat EPEC. First, we used four probes ...

The increase in antibiotic resistance has become a major health concern in recent times. It is therefore essential to identify novel antibacterial targets as well as discover and develop new antibacterial agents. FtsZ, a highly conserved bacterial protein, is responsible for the initiation of cell division in bacteria. The functions of FtsZ inside cells are tightly regulated and any perturbation in its functions leads to inhibition of bacterial division. Recent reports indicate that small molecules targeting the functions of FtsZ may be used as leads to develop new antibacterial agents. To identify small molecules targeting FtsZ and inhibiting bacterial division, we screened a U.S. FDA (Food and Drug Administration)-approved drug library of 800 molecules using an independent computational, biochemical and microbial approach. From this screen, we identified doxorubicin, an anthracycline molecule that inhibits Escherichia coli division and forms filamentous cells. A fluorescence-binding assay ...

Biofilms are communities of surface-adherent bacteria surrounded by secreted polymers known as the extracellular polymeric substance. Biofilms are harmful in many industries, and thus it is of great interest to understand their mechanical properties and structure to determine ways to destabilize them. By performing single particle tracking with beads of varying surface functionalization it was found that charge interactions play a key role in mediating mobility within biofilms. With a combination of single particle tracking and microrheological concepts, it was found that Escherichia coli biofilms display height dependent charge density that evolves over time. Statistical analyses of bead trajectories and confocal microscopy showed inter-connecting micron scale channels that penetrate throughout the biofilm, which may be important for nutrient transfer through the system. This methodology provides significant insight into a particular biofilm system and can be applied to many others to provide ...

SlyA is a member of the MarR family of bacterial transcriptional regulators. Previously, SlyA has been shown to directly regulate only two operons in Escherichia coli K-12 MG1655, fimB and hlyE (clyA). In both cases, SlyA activates gene expression by antagonizing repression by the nucleoid-associated protein H-NS. Here, the transcript profiles of aerobic glucose-limited steady-state chemostat cultures of E. coli K-12 MG1655, slyA mutant and slyA over-expression strains are reported. The transcript profile of the slyA mutant was not significantly different from that of the parent; however, that of the slyA expression strain was significantly different from that of the vector control. Transcripts representing 27 operons were increased in abundance, whereas 3 were decreased. Of the 30 differentially regulated operons, 24 have previously been associated with sites of H-NS binding, suggesting that antagonism of H-NS repression is a common feature of SlyA-mediated transcription regulation. Direct binding of

Risk Assessment of Escherichia coli Infection from Use of Interactive Waterscape Facilities - Escherichia coli;Exposure;Interactive fountain;Risk assessment;

TY - JOUR. T1 - Shotgun optical maps of the whole Escherichia coli 0157. T2 - H7 genome. AU - Lim, Alex. AU - Dimalanta, Eileen T.. AU - Potamousis, Konstantinos D.. AU - Yen, Galex. AU - Apodoca, Jennifer. AU - Tao, Chunhong. AU - Lin, Jieyi. AU - Qi, Rong. AU - Skiadas, John. AU - Ramanathan, Arvind. AU - Perna, Nicole T.. AU - Plunkett, Guy. AU - Burland, Valerie. AU - Mau, Bob. AU - Hackett, Jeremiah. AU - Blattner, Frederick R.. AU - Anantharaman, Thomas S.. AU - Mishra, Bhubaneswar. AU - Schwartz, David C.. PY - 2001. Y1 - 2001. N2 - We have constructed Nhel and Xhol optical maps of Escherichia coli O157:H7 solely from genomic DNA molecules to provide a uniquely valuable scaffold for contig closure and sequence validation. E. coli O157:H7 is a common pathogen found in contaminated food and water. Our approach obviated the need for the analysis of clones, PCR products, and hybridizations, because maps were constructed from ensembles of single DNA molecules. Shotgun sequencing of bacterial ...

We have found that temperature can have a striking effect upon protein export in Escherichia coli, suggesting that there is a cold-sensitive step in the protein export pathway. Cs mutations comprise the largest class of mutations affecting the membrane-localized Sec proteins SecD, SecE, SecF and SecY. Although some of these mutations could encode cold-labile proteins, this is unlikely to account for the Cs phenotype of most export mutants, as mutations which simply produce lower amounts of SecE protein have the same phenotype. Certain signal sequence mutations affecting maltose binding protein are also cold sensitive for export. These effects appear to arise by a specific interaction of cold with certain export defects. We believe that the Cs sec mutations are representative of a large class of conditional lethal mutations, whose conditional phenotype reflects an underlying thermal sensitivity of the process in which they are involved. ...