• Journal of Animal Science and Technology
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• v.63 no.2
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• pp.461-464
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• 2021

Escherichia coli normally colonizes the lower intestine of animals and humans, but some serotypes are foodborne pathogens. The Escherichia coli K_EC180 was isolated from swine feces that were collected from a weaner pig. In this genome announcement, E. coli K_EC180 was sequenced using PacBio RS II and Illumina NextSeq 500 platforms. The complete chromosome of E. coli K_EC180 is composed of one circular chromosome (5,017,281 bp) with 50.4% of guanine + cytosine (G + C) content, 4,935 of coding sequence (CDS), 88 of tRNA, and 22 of rRNA genes. The complete genome of E. coli K_EC180 contains the toxin genes such as shiga-like toxins (stxA and stxB).

• Korean Journal of Microbiology
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• v.30 no.6
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• pp.421-424
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• 1992

Escherichia coli JM83 harboring penicilin G acylase gene of Bacillus megaterium ATCC14945 produced a protein in large amount (>20% of the total protein). The protein was identified as GroEL, one of the E. coli heat shock protein, by N-terminal amino acid sequence analysis. It was found that GroEL was induced by the expressed foreign penicilin G acylase at both 27 and $37^{\circ}C$.

• Journal of Microbiology and Biotechnology
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• v.26 no.5
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• pp.975-987
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• 2016

Lactobacillus plantarum (L. plantarum) is a representative probiotic. In particular, L. plantarum is the first commensal bacterium to colonize the intestine of infants. For this reason, the initial settlement of L. plantarum can play an important role in determining an infant's health as well as their eventual health status as an adult. In addition, L. plantarum combats pathogenic infections (such as Escherichia coli (E. coli), one of the early pathogenic colonizers in an unhealthy infant gut) by secreting antimicrobial substances. The aim of this research was to determine how L. plantarum combats E. coli infection and why it is a representative probiotic in the intestine. Consequently, this research observed that E. coli releases uracil. L. plantarum specifically recognizes E. coli-derived uracil, which increases the growth rate and production of antimicrobial substance of L. plantarum. In addition, through the inhibitory activity test, this study postulates that the antimicrobial substance is a protein and can be considered a bacteriocin-like substance. Therefore, this research assumes that L. plantarum exerts its antibacterial ability by recognizing E. coli and increasing its growth rate as a result, and this phenomenon could be one of the reasons for L. plantarum settling in the intestine of infants as a beneficial bacterium.

• Journal of Microbiology and Biotechnology
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• v.16 no.8
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• pp.1169-1173
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• 2006

Imaging ellipsometry (IE) for detection of binding of Escherichia coli O157:H7 (E. coli O157:H7) to an immunosensor is reported. A protein G layer, chemically bound to a self-assembled layer of 11-mercaptoundecanoic acid (11-MUA), was adopted for immobilization of monoclonal antibody against E. coli O157:H7 (Mab). The immobilization of antibody was investigated using surface plasmon resonance. To fabricate antibody spots on a gold surface, protein G solution was spotted onto the gold surface modified with an 11-MUA layer, followed by immobilizing Mab on the protein G spot. Ellipsometric images of the protein G spot, the Mab spot, and Mab spots with binding of E. coli O157:H7 in various concentrations were acquired using the IE system. The change of mean optical intensity of the Mab spots in the ellipsometric images indicated that the lowest detection limit was $10^3$CFU/ml for E. coli O157:H7. Thus, IE can be applied to an immunosensor for detection of E. coli O157:H7 as a detection method with the advantages of allowing label-free detection, high sensitivity, and operational simplicity.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.575-578
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• 2000

The N-acetylneuraminate lyase(NALase) from Escherichia coli was cloned and it was compared to that from Haemophilus influenzae and Clostridium perfringens. NALase from E. coli was expressed in very high level(about 6U/mg). The ManNAc Km value of three enzymes was almost the same. Pyruvate inhibited from H. influenzae was inhibited by GlcNAc in lower level than the others. The crude extract has about 30 times more activity than the cell for the substrate and product diffusion limit problem. The pH stability of three enzymes at pH 11 was also checked for its importance in the direct synthesis of Neu5Ac from GlcNAc and pyruvate at high alkaline condition.

• Journal of Food Hygiene and Safety
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• v.12 no.3
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• pp.200-204
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• 1997

Effects of benzoate (0~0.6 g/$\ell$ ) and sorbate (0~2.0 g/$\ell$) on the growth of Escherichia coli O157:H7 in tryptic soy broth at various pH levels (4~8) and temperatures (4$^{\circ}C$, 37$^{\circ}C$) were investigated. Benzoate and sorbate were inhibited the growth of E. coli O157:H7 up to 12 hours cultivation at 4$^{\circ}C$, and 2.0 g/$\ell$ sorbate was only inhibited during 48 hours cultivation at 37$^{\circ}C$. Among the pH levels tested, pH 4 showed significant inhibitory effect against the E. coli O157:H7 on 4$^{\circ}C$ and at 37$^{\circ}C$, respectively. When used in combination 0.2 g/$\ell$ benzoate and sorbate were completely inhibited the growth of E. coli O157:H7 on pH 4 and at 37$^{\circ}C$. While on pH 5 at 4$^{\circ}C$, all of the concentration tested did not exert any inhibitory effect. The combined effects were retarded more than single treatment of E. coli O157:H7.

• Applied Chemistry for Engineering
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• v.17 no.5
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• pp.557-560
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• 2006

The epoxide hydrolase (EH) of Aspergillus niger LK was expressed to high levels in Escherichia coli based on codon usage. E. coli, Rosetta (DE3)PLysS, containing a large number of tRNAs for rare-codons was employed as a host strain. The recombinant E. coli expressing A. niger EH showed an enhanced enantioselective hydrolysis activity toward racemic styrene oxide. Enantiopure (S)-styrene oxide with a high enantiopurity of 99% ee was obtained from racemic substrates.

• BMB Reports
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• v.40 no.1
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• pp.107-112
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• 2007

To study the functioning of HSP70 in Escherichia coli, we selected NtHSP70-2 (AY372070) from among three genomic clones isolated in Nicotiana tabacum. Recombinant NtHSP70-2, containing a hexahistidine tag at the amino-terminus, was constructed, expressed in E. coli, and purified by $Ni^{2+}$ affinity chromatography and Q Sepharose Fast Flow anion exchange chromatography. The expressed fusion protein, $H_6NtHSP70$-2 (hexahistidine-tagged Nicotiana tabacum heat shock protein 70-2), maintained the stability of E. coli proteins up to 90$^{\circ}C$. Measuring the light scattering of luciferase (luc) revealed that NtHSP70-2 prevents the aggregation of luc without ATP during high-temperature stress. In a functional bioassay (1 h at 50$^{\circ}C$) for recombinant $H_6NtHSP70$-2, E. coli cells overexpressing $H_6NtHSP70$-2 survived about seven times longer than those lacking $H_6NtHSP70$-2. After 2 h at 50$^{\circ}C$, only the E. coli overexpressing $H_6NtHSP70$-2 survived under such conditions. Our NtHSP70-2 bioassays, as well as in vitro studies, strongly suggest that HSP70 confers thermo-tolerance to E. coli.

• Microbiology and Biotechnology Letters
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• v.48 no.2
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• pp.121-128
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• 2020

Diarrhea is a major public health concern associated with pathogenic Escherichia coli infections. Food-borne pathogenic E. coli can lead to large diarrheal outbreaks and hence, there is a need to estimate the frequency of pathogenic E. coli load in the various types of meat available in markets. In the present study, we classified and characterized diarrheagenic E. coli isolates collected from 399 raw meat samples from retail sources in Korea. Shiga toxin-producing E. coli (STEC) were detected in 11 (9.7%) samples, including nine strains (8.0%) in beef and two strains (1.8%) in chicken. The frequency of the detected virulence markers were as follows: astA, 28.3%; escV,18.6%; eaeA,17.7%; ent, 7.0%; EHEC-hly, 4.4%; stx1, 3.5%; and stx2, 3.5%. We did not observe any typical EPEC, EIEC, or ETEC virulence determinants in any of the samples. The STEC serotype O26 was detected in one sample, but no other serogroups (O91, O103, O128, O157, O145, O111, and O121) were found. Further research is needed to better understand the virulence mechanism of STEC serotypes, their ecology, and prevalence in animals, food, and the environment. These results will help improve risk assessment and predict the sources of food poisoning outbreaks.

• Journal of Yeungnam Medical Science
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• v.30 no.2
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• pp.83-89
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• 2013

Background: The prevalence of extended-spectrum ${\beta}$-lactamase (ESBL)-producing Escherichia coli is increasing rapidly worldwide. Treatment options for ESBL-producing E. coli are limited, and infections caused by this organism are associated with improper antibiotic use, a long hospital stay, and increased mortality. Thus, the assessment and early recognition of the risk factors of nosocomial infections due to ESBL-producing E. coli are important for the infection control and proper treatment. Methods: A case-control study was performed that included nosocomial episodes of ESBL-producing E. coli bacteremia at a tertiary care hospital from January 2004 to December 2007. For each case patient, three controls were randomly selected and data on predisposing factors were collected. Results: Fifty-five cases of nosocomial ESBL-producing E. coli bacteremia were studied. Carbapenem usage (OR: 11.3, 95% CI: 1.1-115.9, p=0.041), quinolone usage (OR: 4.5, 95% CI: 1.1-18.8, p=0.042), biliary obstructive disease (OR: 11.8, 95% CI: 3.0-46.7, p<0.001) and the APACHE II score (OR: 1.3, 95% CI: 1.2- 1.5, p<0.001) were analyzed as independent risk factors of nosocomial ESBL-producing E. coli bacteremia. Conclusion: Our results showed that physicians caring for patients with risk factors of nosocomial bacteremia should consider ESBL-producing E. coli as the causative organisms of the disease.