• Korean Journal of Microbiology
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• v.45 no.2
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• pp.163-169
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• 2009

This study was performed to investigate the type of extended-spectrum $\beta$-lactamases (ESBL) produced by bacteria isolated from the sewage of wastewater treatment plant at Minragdong, Suyong-gu in Busan. The facility is located at sushi restaurants and guides its drain water to the wastewater treatment plant at Yonghodong, Nam-gu in Busan. Samples were collected on January, 2009. A total of 19 strains were selected as potential ESBL positive strains through a double disk synergy test. On the basis of the results from biochemical tests including indole, methyl-red, Voges-Proskauer, Simmon's citrate, decarboxylase-dihydrolase and sugar-fermentation tests, the 19 strains were identified with 16 strains of Escherichia coli and 3 strains of Klebsiella pneumoniae. Out of 19 strains, 4 transconjugants against Escherichia coli J53, which is sodium azide resistant recipient strain, were obtained. The plasmids isolated from transconjugants were used for PCR analysis. The type of each extended-spectrum $\beta$-lactamase (ESBL) produced by the strains was determined on the basis of isoelectric focusing analysis and DNA sequencing. The results indicated that the types of ESBL from Klebsiella pneumoniae were SHV-12 (3 strains), and Escherichia coli was SHV-12/TEM-1 (1 strain), respectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.10
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• pp.1606-1610
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• 2005

The effects of Whangkumtang extract and Scutellariae radix extract on the microbial growth were investigated. The antimicrobial activities and cell growth inhibiting effects were investigated to selected strains with different concentrations of Whangkmtang and Scutellariae radix extracts. Whangkmtang and Scutellariae radix extracts showed the antimicrobial activities on Staphylococcus aureus, Bacillus cereus, Shigella sonnei, Shigella flexneri, Salmonella Typhimurium, Salmonella Enteritidis, Vibrio parahaemolyticus, Escherichia coli O111 and Escherichia coli O126. Whangkumtang and Scutellariae radix extracts did not show the antimicrobial activity on Listeriamonocytogenes. Scutellariae radix extract showed the antimicrobial activity on Escherichia coli O157 but Whangkumtang extract did not, Minimum inhibitory concentrations (MIC) of Whangkumtang extract for each strain appeared to 40 mg/mL on Staphylococcus aureus and Bacillus cerus, 100 mg/mL on Shigella Flexneri and Salmonella enteritidis. The MICs of Sutellariae radix extract appeared to 10 mg/mL on Bacillus cereus, 20 mg/UL on Staphylococn aureus, Shigellanexneri and Salmonella Enteritidis. Scutellariae radix extract showed the higher antimicrobial activity than Whangkumtang extract. The cell growth inhibitions by Whangkumtang and Scutellariae radix extracts were observed from Staphylococcus aureus and Bacillus cereus, repectively, during 48-hr incubation period.

• Applied Biological Chemistry
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• v.26 no.1
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• pp.35-40
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• 1983

The inhibitory activity of 20 Lactic strains from Kimchi was tested against Escherichia coli and other microorganisms. Of the lactic strains investigated, A7 (Pediococcus cerevisiae) and C4(Leuconostoc spp.) were the most effective in restricting the growth of test organisms. The mixed culture inoculation of each selected lactic strain and Escherichia coli resulted in a drastic reduction in the plate count of Escherichia coli after 24 hours. Similar results were obtained when Staphylococcus aureus and Bacillus cereus were used as test organisms. For all test organisms, the presence of A7 caused a higher death rate constant than that of C4. Addition of catalase in the mixed culture did not prevent inhibition, suggesting that hydrogen peroxide did not cause the inhibition. The filtrate of A7 culture added to Escherichia coli showed identical inhibitory action, however heat treatment of filtrate at $80^{\circ}C$ 30min. destroyed the inhibitory activity. A7 filtrate treated with trypsin substantially lost the inhibitory effect, but not by pepsin. The results imply that the protein-like compound(s) is the principal inhibitor produced by this lactic strain.

• KSBB Journal
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• v.13 no.2
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• pp.168-173
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• 1998

Gamma irradiated and non-irradiated Agrimonia pilosa Ledebour were extracted by 70% ethanol. The combined effects of the Agrimonia pilosa Ledebour extract and NaCl on survival of Escherichia coli O157:H7 in tryptic soy broth were investigated. E. coli O157:H7 decreased ca 1 log cycle by the addition of 2% sample extract, and the anthbacterial activity was increased as the concentration of sample extract was increased. The irradiation effect of the sample on antibacterial activity was not observed. On the treatment of NaCl alone, E. coli O157:H7 was inactivated (ca 3~4 log cycle reduction within 48 hr) in more than 7% NaCl. The higher inactivation(ca 5 log cycle reduction within 48 hr) occurred in the presence of 2% sample extract and 5% NaCl than in the addition of each alone. The extracted antibacterial substance was stable in the pH range of 4.0 to 7.0, heat treatment at 121$^\circ C$ for 15 min, and freezing at -18$^\circ C$ and thawing at 37$^\circ C$. There fore, the sample extract, would substantially increase the food-safety in terms of E. coli O157:H7.

• 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 Clinical Laboratory Science
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• v.54 no.2
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• pp.119-124
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• 2022

Pseudomonas aeruginosa (P. aeruginosa), Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) are typical opportunistic pathogens. Moreover, these bacteria are known to possess multidrug-resistant (MDR) properties. This study investigates the antimicrobial activity of six fermented products, which have varying efficacies against P. aeruginosa, E. coli, and S. aureus. To identify novel candidate genes, differential expression analysis was performed using an annealing control primer. In the disk diffusion method, Fig vinegar (FV) and Diospyros kaki Thunb vinegar (DTV) showed the greatest increase in inhibition compared to other fermented products, whereas fermented Korean traditional nature herb (FKTNH) had no antibacterial effect. This study identified down-regulation of Escherichia coli O157:H7 ompW gene for outer membrane protein W, whereas gene for synthetic construct Lao1 gene for L-amino acid oxidase were up-regulated in E. coli treated with 5% FV. Consuming fermented vinegar helps prevent bacterial infections. Especially, FV and DTV are potentially useful alternative natural products for multidrug resistance. Furthermore, both are expected to be used as effective natural antimicrobial agents, such as disinfectants.

• Journal of Life Science
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• v.20 no.5
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• pp.676-682
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• 2010

This study focused on typing of the extended-spectrum $\beta$-lactamase (ESBL) produced in organisms isolated from a natural environment, rather than a clinical setting. Samples were collected from drain water issuing from a sewage plant in Kwanganri (Busan, Korea). Following double disk synergy testing, 29 strains were selected as potential ESBL positive strains. Of these, 15 strains were transconjugants of the sodium azide resistant recipient strain Escherichia coli J53 and analyzed biochemically including indole, methyl-red, Voges-Proskauer, Simmon's citrate, decarboxylase-dihydrolase and sugar-fermentation tests. The tests classified the 15 strains as Klebsiella pneumoniae (n=13) and Escherichia coli (n=2). The type of ESBL from each strain was deduced by isoelectric focusing point analysis and DNA sequencing. The results indicated that the types of ESBL were SHV-12 (n=4) and SHV-12/TEM-1 (n=9) from K. pneumoniae and TEM-1 (n=2) from E. coli strains.

• Journal of Microbiology and Biotechnology
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• v.18 no.4
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• pp.742-745
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• 2008

Inactivation of Escherichia coli O157:H7 and Salmonella typhimurium was evaluated on inoculated chicken by aqueous chlorine dioxide ($CIO_2$) treatment. Chicken samples were inoculated with 6-7 log CFU/g of Escherichia coli O157:H7 and Salmonella typhimurium, respectively. The chicken samples were then treated with 0, 50, and 100 ppm of $CIO_2$ solution and stored at $4{\pm}1^{\circ}C$. Aqueous $CIO_2$ treatment decreased the populations of the pathogenic bacteria on the chicken breast and drumstick. In particular, 100 ppm $CIO_2$ treatment on the chicken breast and drumstick reduced Escherichia coli O157:H7 and Salmonella typhimurium by 1.00-1.27 and 1.37-1.44 log CFU/g, respectively. Aqueous $CIO_2$ treatment on the growth of the bacteria was continuously in effect during storage, resulting in the decrease of the populations of Escherichia coli O157:H7 and Salmonella typhimurium. These results suggest that aqueous $CIO_2$ treatment should be useful in improving the microbial safety of chicken during storage.

• Journal of Microbiology and Biotechnology
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• v.20 no.9
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• pp.1300-1306
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• 2010

Ethyl (R, S)-4-chloro-3-hydroxybutanoate (ECHB) is a useful chiral building block for the synthesis of L-carnitine and hypercholesterolemia drugs. The yeast reductase, YOL151W (GenBank locus tag), exhibits an enantioselective reduction activity, converting ethyl-4-chlorooxobutanoate (ECOB) exclusively into (R)-ECHB. YOL151W was generated in Escherichia coli cells and purified via Ni-NTA and desalting column chromatography. It evidenced an optimum temperature of $45^{\circ}C$ and an optimum pH of 6.5-7.5. Bacillus subtilis glucose dehydrogenase (GDH) was also expressed in Escherichia coli, and was used for the recycling of NADPH, required for the reduction reaction. Thereafter, Escherichia coli cells co-expressing YOL151W and GDH were constructed. After permeablization treatment, the Escherichia coli whole cells were utilized for ECHB synthesis. Through the use of this system, the 30 mM ECOB substrate could be converted to (R)-ECHB.

• Korean Journal of Microbiology
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• v.32 no.1
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• pp.28-33
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• 1994

In normal cells tau protein is associated with axonal microtubules, whereas in Alxheimer's disease it is immobilized in the somatodendritic compartment of certain nerve cells as a major component of the paired helical filament. As a part of the study to analyze the nature of the paired helical filament (PHF) deposits and some related factors in brain, we have cloned and expressed a human tau gene cDNA in Escherichia coli to obtain the recombinant human tau protein in abundance.