• Journal of Food Hygiene and Safety
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• v.12 no.3
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• pp.175-180
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• 1997

Escherichia coli O157:H7 and Salmonella ser. typhimurium are pathogens involved in food poisoning in numerous countries. This study aimed to obtain knowleges on the survival of E. coli O157:H7 KSC 109 and S. ser. typhimurium ATCC 14028 in fermentedmilk products which were on sale in Suwon Yakult supplier. To the final concentration of 103~104 cfu/$m\ell$ of E. coli O157:H7 KSC 109 or S. wer. typhimurium ATCC 14028 in the fermented milks, Metchnikoff, Ace, Yakult, Mastoni and Super 100 were inoculated with these pathogens and then were stored at 4$^{\circ}C$ and viable cells of these pathogens were periodically counted. The results showed that the survival of two pathogens differed in the different types of fermented milks tested. Number of suriviving E. coli O157:H7 KSC 109 and S. ser. typimurium ATCC 14028 cells (initial inoculum, 103~104 cfu/$m\ell$) were decreased to 101, 102 cfu/$m\ell$ in Ace after 100 hours, and were decreased gradually to 101 cfu/$m\ell$ in Yakult after 250 hours. In the other fermented milks, viable cells of E. coli O157:H7 KSC 109 was not drastically decreased but those of S. ser. typhimurium ATCC 14028 was decreased gradually to 102 (Mastoni), and to 101 cfu/$m\ell$ (Super 100) after 250 hours. It appeared that S. ser. typhimurium ATCC 14028 was more susceptible than E. coli O157:H7 KSC 109 at low pH. Vibale cells of E. coli O157:H7 KSC 109 was not drastically decreased in most of fermented milks tested except Ace and Yakult, but in general, S. ser. typhimurium ATCC 14028 was drastically decreased in most of the fermented milks. The major ingibition factor against these pathogens in the fermented milks during storage at 4$^{\circ}C$ appeared to be the acidity and the metabolites produced by the starters bacteria used in fermented milk products.

• Journal of Naturopathy
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• v.7 no.1
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• pp.20-25
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• 2018

The purpose of this study was investigated to observe the relatively low amino acid mutations in six different strains of ATCC or KCTC Salmonella strains (four species and two isolates). The mutations in the strains were to be detected and compared with the genes csgA and csgB corresponding to the Thin aggregative fimbriae. Amino acid mutations in the strains were observed from Ser20→ Gly(AGT→GGT) in the csgA gene, Asp25→Ala(GAT→GCT) and Lys66→Thr(AAA→ACA) in the csgB gene. Among the six strains, the two most common amino acid variations were observed in S. typhimurium - TH strains. On the other hand, no mutation of nucleotide sequence was observed in the strains of S. typhimurium ATCC 13311 and S. typhimurium KCTC 1925. In conclusion the genes csgA and csgB in the strains may be useful for the evaluation and detection of amino acid mutation.

• Korean Journal of Microbiology
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• v.36 no.1
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• pp.46-51
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• 2000

Salmonella typhi is one of important causes of human enteric infections. S. typhi KNIH100 was isolated from a patient of typhoid fever in Korea. We cloned a 5.0 kb SalⅠ fragment containing the aroA gene encoding a 5-enolpyruvylshikimate-3-phosphate synthetase from chromosomal DNA of this strain. This recombinant plasmid was named pSAL80. E. coli CGSC2829, an aroA- mutant, was not grown on the M9 minimal medium but E. coli CGSC2829 (pSAL80) was grown on the M9 minimal medium. The aroA gene was composed of 1,284 base pairs with ATG initiation codon and TAA termination codon. Sequence comparison of the aroA gene exhibited 99%, 98%, and 77% identity with those of S. typhi Ty2, S. typhimurium, and E. coli respectively. As in the cases of Shigella sonnei and E. coli, the serC and aroA genes lie in a single operonic structure.

• Microbiology and Biotechnology Letters
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• v.20 no.6
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• pp.699-703
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• 1992

An oriental drug, named NP-S, traditionally used as a therapeutic agent for hepatitis B was characterized by separating into volatile and non-volatile fractions. The volatile fraction contained ammonia as determined by ammonia kit and eight peaks when it was analyzed by gas chromatography that are not identified yet. The elemental analysis showed that the non-volatile fraction contained 15.5% carbon, 4.8% hydrogen, 11% nitrogen, and 10% sulfur along with a few trace elements such as Cl, Si, Mg and Zn. NP-S contained 6.7% peptide, 0.3% free amino acids such as Lys, Pro, Arg, lie, Tyr, Phe, His, Thr and Ser and 0.1% inorganic phosphate. The drug showed antimicrobial activity against Salmonella typhimurium, StaPhylococcus aureus and Candida albieans and also had antioxidant activity when thiobarbituric acid reacting substances(TBARS) method was applied.

• The Journal of the Korean Society for Microbiology
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• v.19 no.1
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• pp.55-64
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• 1984

The clinical specimens used in this study were collected during the period from March 4, to December 30, 1983, from children's hospitals in Seoul area. They came from clinically apparent cases of diarrheal disease in hospitals. Many specimens were taken from rectal Swabs. During this period, 2166 stool cultures were streaked onto MacConkey plate and were them deposited in selenite broth. Colonies resembling pathogens on MacConkey medium were picked to KIA, Urea agar, malonate broth, ONPG broth, SIM. Reaction on those media cultures were identified biochemically with using API 20E test kit and confirmed serologically with commercially avabile Salmonella antisera(Difco) or Shigella antisera(Denka, Japan). The sensitivity of Salmonella and Shigella tested to ampicillin cephalosporin, chloramphenicol, colistin, gentamicin, tetracycline, streptomycin, nalidixic acid, neomycin, polymyxin B was performed by means of disc diffusion method recommended by Bauer-Kirby, using the discs prepared in BBL Laboratory. 1. There were 34 (1.6%) isolations of Salmonella cultures and 52(2.4%) isolations of Shigella from the 2,116 specimens. Only 53%of Salmonella were isolated by direct streaking on MacConkey plating media, by contrast, 80% of the Shigella were isolated directly. 2. Shigella flexneri types comprised 56% of the Shigellae isolate from 52 Shigellae identified 24% of Salmonella enteritidis ser typhimurium were identified. 3. Concerning to Salmonella and Shigella occurance according to month and sex, They shows relatively higher for the male than in case of female, and 2-3 age were shown the highest group. 4. October is the month with highest incidences. 5. In the sensitivity patterns of Shigellae, most of them were appeared to be resistant ampicillin, streptomycin, tetracycline, in case of Salmonella, 15% of them were resistant to chloramphenicol.

• Journal of Microbiology and Biotechnology
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• v.23 no.2
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• pp.225-236
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• 2013

Among several bacteria examined, an antibacterial-producing Lactobacillus strain with probiotic characteristics was selected and identified based on 16S rRNA gene sequencing. Subsequent purification and mode of action of the antibacterial compounds on target cells including E. coli were investigated. Maximum production of the antibacterial compound was recorded at 18 h incubation at $30^{\circ}C$. Interestingly, antibacterial activity remained unchanged after heating at $121^{\circ}C$ for 45 min, 24 h storage in temperature range of $70^{\circ}C$ to room temperature, and 15 min exposure to UV light, and it was stable in the pH of range 2-10. The active compounds were inactivated by proteolytic enzymes, indicating their proteinaceous nature, and, therefore, referred to as bacteriocin-like inhibitory substances. Isolation and partial purification of the effective agent was done by performing ammonium sulfate precipitation and gel filtration chromatography. The molecular mass of the GFC-purified active compound (~3 kDa) was determined by Tris-Tricine SDS-PAGE. To predict the mechanisms of action, transmission electron microscopy (TEM) analysis of ultrathin sections of E. coli before and after antibacterial treatment was carried out. TEM analysis of antibacterial compounds-treated E. coli demonstrated that the completely altered bacteria appear much darker compared with the less altered bacteria, suggesting a change in the cytoplasmic composition. There were also some membrane-bound convoluted structures visible within the completely altered bacteria, which could be attributed to the response of the E. coli to the treatment with the antibacterial compound. According to the in vivo experiments oral administration of L. plantarum HKN01 resulted in recovery of infected BALB/c mice with Salmonella enterica ser. Typhimurium.

• Journal of Microbiology and Biotechnology
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• v.20 no.12
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• pp.1735-1743
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• 2010

The full-length genes gyrB (2,415 bp), parC (2,277 bp), and parE (1,896 bp) in Edwardsiella tarda were cloned by PCR with degenerate primers based on the sequence of the respective quinolone resistance-determining region (QRDR), followed by elongation of 5' and 3' ends using cassette ligation-mediated PCR (CLMP). Analysis of the cloned genes revealed open reading frames (ORFs) encoding proteins of 804 (GyrB), 758 (ParC), and 631 (ParE) amino acids with conserved gyrase/topoisomerase features and motifs important for enzymatic function. The ORFs were preceded by putative promoters, ribosome binding sites, and inverted repeats with the potential to form cruciform structures for binding of DNA-binding proteins. When comparing the deduced amino acid sequences of E. tarda GyrB, ParC, and ParE with those of the corresponding proteins in other bacteria, they were found to be most closely related to Escherichia coli GyrB (87.6% identity), Klebsiella pneumoniae ParC (78.8% identity), and Salmonella Typhimurium ParE (89.5% identity), respectively. The two topoisomerase genes, parC and parE, were found to be contiguous on the E. tarda chromosome. All 18 quinolone-resistant isolates obtained from Korea thus far did not contain subunit alternations apart from a substitution in GyrA (Ser83$\rightarrow$Arg). However, an alteration in the QRDR of ParC (Ser84$\rightarrow$Ile) following an amino acid substitution in GyrA (Asp87$\rightarrow$Gly) was detected in E. tarda mutants selected in vitro at $8{\mu}g/ml$ ciprofloxacin (CIP). A mutant with a GyrB (Ser464$\rightarrow$Leu) and GyrA (Asp87$\rightarrow$Gly) substitution did not show a significant increase in the minimum inhibitory concentration (MIC) of CIP. None of the in vitro mutants exhibited mutations in parE. Thus, gyrA and parC should be considered to be the primary and secondary targets, respectively, of quinolones in E. tarda.