• Korean Journal of Food Science and Technology
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• v.43 no.2
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• pp.176-181
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• 2011

Cronobacter sakazakii and Salmonella enterica Typhimurium are hazardous pathogens, especially for ready-toeat foods. For control of pathogens, the virulent bacteriophages were isolated, identified, and applied to infant formula milk and vegetable juice. The phages were isolated from swine feces and identified by morphology and molecular characteristics. ES2 phage for C. sakazakii and ST2 phage for S enterica Typhimurium were identified as Myoviridae and Siphoviridae, respectively. Their burst sizes were $52{\pm}5PFU/cell$ for ES2 phage and $21{\pm}3PFU/cell$ for ST2 phage after latent period of 30-40 minutes. ST2 phage showed higher heat stability at $60^{\circ}C$ than ES2 phage. ES2 phage held the growth of C. sakazakii untill 6 hr afterwhich the number decreased when applied to the infant formula milk and vegetable juice. ST2 phage also showed growth inhibition so that the number of S. enterica Typhimurium decreased. Therefore, virulent bacteriophages might be an agent for the growth inhibition of C. sakazakii and S. enterica Typhimurium in such the ready-to-eat foods.

• Korean Journal of Veterinary Research
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• v.56 no.2
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• pp.103-108
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• 2016

Salmonellosis is a major bacterial zoonosis that causes self-limited enteritis in animals and foodborne disease and typhoid fever in humans. Recently, multi-drug-resistant strains of Salmonella spp. have increased and caused more serious problems in public health. The present study investigated the antibacterial effects of egg-white lysozyme (EWL) against Salmonella (S.) Typhimurium and the therapeutic effects of EWL for murine salmonellosis. Evaluation of the antibacterial effects of EWL against S. Typhimurium revealed a minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of EWL of 6.25 and $300{\mu}g/mL$, respectively. In the bacterial growth inhibition test, EWL at 300 (p < 0.05) and $600{\mu}g/mL$ (p < 0.01) significantly inhibited the growth of S. Typhimurium at 4 h post-incubation. EWL administration at MIC (LYS-1), MBC (LYS-2) and $2{\times}MBC$ (LYS-3) for 14 days resulted in mortality of mice infected with S. Typhimurium of 70, 40 and 10%, respectively, while that of control mice (CON) was 90%. Counts of S. Typhimurium in murine spleens were significantly lower in LYS-2 and LYS-3 than CON (p < 0.05). The results of this study indicate that EWL has the potential for treatment of ICR mice infected with S. Typhimurium.

• Journal of Korean Neurosurgical Society
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• v.55 no.3
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• pp.131-135
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• 2014

Objective : With the growing interests of bacteria as a targeting vector for cancer treatment, diverse genetically engineered Salmonella has been reported to be capable of targeting primary or metastatic tumor regions after intravenous injection into mouse tumor models. The purpose of this study was to investigate the capability of the genetically engineered Salmonella typhimurium (S. typhimurium) to access the glioma xenograft, which was monitored in mouse brain tumor models using optical bioluminescence imaging technique. Methods : U87 malignant glioma cells (U87-MG) stably transfected with firefly luciferase (Fluc) were implanted into BALB/cAnN nude mice by stereotactic injection into the striatum. After tumor formation, attenuated S. typhimurium expressing bacterial luciferase (Lux) was injected into the tail vein. Bioluminescence signals from transfected cells or bacteria were monitored using a cooled charge-coupled device camera to identify the tumor location or to trace the bacterial migration. Immunofluorescence staining was also performed in frozen sections of mouse glioma xenograft. Results : The injected S. typhimurium exclusively localized in the glioma xenograft region of U87-MG-bearing mouse. Immunofluorescence staining also demonstrated the accumulation of S. typhimurium in the brain tumors. Conclusion : The present study demonstrated that S. typhimurium can target glioma xenograft, and may provide a potentially therapeutic probe for glioma.

• Korean Journal of Poultry Science
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• v.36 no.3
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• pp.201-206
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• 2009

This study was carried out to investigate dietary effects of illite on humoral immune response against Salmonella typhimurium flagella in Hyline Brown laying hens. Total of twenty eight 36-week-old hens were divided into two groups; The first was fed commercial diet as control and the other was fed diet containing 2 % illite. Each group was divided into 2 sub-groups and then performed immunization of Salmonella flagella with different adjuvants which were Freund's adjuvant and croton oil. The rates of egg-production in all groups were normal range but no difference was found between illite-treated and untreated groups. The serum antibody titers of Freund's adjuvant-used subgroup in illite fed groups were significantly increased, especially from 6-to 9-week after $1^{st}$ immunization compared to those of control groups (p<0.05). And the antibody titers of croton oil-used subgroup in illite-fed groups were also significantly increased, especially at 4-, 6- and 7-week (p<0.05). The results demonstrated that the feeding illite stimulated the immune response against S. typhimurium flagella antigen in laying hens and suggest that the supplementation of illite to the poultry diets may support protective effects against bacterial infections such as Salmonellosis.

• IMMUNE NETWORK
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• v.12 no.6
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• pp.284-290
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• 2012

Innate immune cells sense and respond to the cytoplasmic infection of bacterial pathogens through NLRP3, NLRC4 or AIM2 inflammasome depending on the unique molecular pattern of invading pathogens. The infection of flagellin- or type III secretion system (T3SS)-containing Gram-negative bacteria such as Salmonella enterica serovar Typhimurium (S. typhimurium) or Pseudomonas aeruginosa (P. aeruginosa) triggers NLRC4-dependent caspase-1 activation leading to the secretion of proinflammatory cytokines such as interleukin-1-beta (IL-$1{\beta}$) and IL-18. Previous studies have shown that apoptosis-associated speck-like protein containing a CARD (ASC) is also required for Salmonella-induced caspase-1 activation, but it is still unclear how ASC contributes to the activation of NLRC4 inflammasome in response to S. typhimurium infection. In this study, we demonstrate that S. typhimurium triggers the formation of ASC oligomer in a potassium depletion-independent manner as determined by in vitro crosslinking and in situ fluorescence imaging. Remarkably, inhibition of potassium efflux failed to block Salmonella-promoted caspase-1 activation and macrophage cell death. These results collectively suggest that ASC is substantially oligomerized to facilitate the activation of caspase-1 in response to S. typhimurium infection. Contrary to NLRP3 inflammasome, intracellular potassium depletion is not critical for NLRC4 inflammasome signaling by S. typhimurium.

• Molecules and Cells
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• v.43 no.12
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• pp.989-1001
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• 2020

Salmonella enterica serovar Typhimurium (S. Typhimurium) is a facultative intracellular pathogen that causes salmonellosis and mortality worldwide. S. Typhimurium infects macrophages and survives within phagosomes by avoiding the phagosome-lysosome fusion system. Phagosomes sequentially acquire different Rab GTPases during maturation and eventually fuse with acidic lysosomes. Lysophosphatidylcholine (LPC) is a bioactive lipid that is associated with the generation of chemoattractants and reactive oxygen species (ROS). In our previous study, LPC controlled the intracellular growth of Mycobacterium tuberculosis by promoting phagosome maturation. In this study, to verify whether LPC enhances phagosome maturation and regulates the intracellular growth of S. Typhimurium, macrophages were infected with S. Typhimurium. LPC decreased the intracellular bacterial burden, but it did not induce cytotoxicity in S. Typhimurium-infected cells. In addition, combined administration of LPC and antibiotic significantly reduced the bacterial burden in the spleen and the liver. The ratios of the colocalization of intracellular S. Typhimurium with phagosome maturation markers, such as early endosome antigen 1 (EEA1) and lysosome-associated membrane protein 1 (LAMP-1), were significantly increased in LPC-treated cells. The expression level of cleaved cathepsin D was rapidly increased in LPC-treated cells during S. Typhimurium infection. Treatment with LPC enhanced ROS production, but it did not affect nitric oxide production in S. Typhimurium-infected cells. LPC also rapidly triggered the phosphorylation of IκBα during S. Typhimurium infection. These results suggest that LPC can improve phagosome maturation via ROS-induced activation of NF-κB pathway and thus may be developed as a therapeutic agent to control S. Typhimurium growth.

• Journal of Food Hygiene and Safety
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• v.20 no.3
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• pp.175-178
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• 2005

Clean Natural is a new disinfectant of which main components are propolis and wood vinegar from Quercus mongolica. To evauate the bacterial reverse mutation of Clean Watural, the in vitro Ames test using Salmonella typhimurium TA98, TA100, TA102, TA1535 and TA1537 were performed with clean natural at the concentrations 0, 5, 2.5, and 1.25 mg/ml/plate. Clean Natural was negative in Ames test with Salmonella typhymuyium with and without rat liver microsomal enzyme (S-9 fraction). These results indicate that Clean Watural does not cause bacterial reverse mutation.

• Journal of Microbiology and Biotechnology
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• v.19 no.12
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• pp.1527-1535
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• 2009

Polyphosphate (polyP) plays diverse physiological functions in prokaryotes and eukaryotes, but most of their detailed mechanisms are still obscure. Here, we show that deletion of polyphosphate kinase (PPK), the principal enzyme responsible for synthesis of polyP, resulted in augmented expression of cAMP receptor protein (CRP) and rpoS and lowered $H_2O_2$ sensitivity in Salmonella Typhimurium ATCC14028. The binding of cAMP-CRP complex to rpoS promoter and further stimulation of its transcription were proved through electrophoretic mobility shift assay, lacZ fusion, and exogenous cAMP addition, respectively. The rpoS expression increased in cpdA (cAMP phosphodiesterase coding gene) mutant, further suggesting that cAMP-CRP upregulated rpoS expression. These results demonstrate that PPK affects oxidative stress response by modulating crp and rpoS expression in S. Typhimurium.

• Journal of environmental and Sanitary engineering
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• v.3 no.1 s.4
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• pp.41-67
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• 1988

Twelve residual pesticides which is applied mainly on the fruits and vegetables cultivation were tested for mutagenic activity using Salmonella typhimurium. The results were as follows. 1) The pesticides tested - Thalonil, Monopho, Tedion, Danoton, Ometon, Prosing, EPN, Phentoate, Parathion, 8appiran and Captan-, except Dicofol, showed mutagenic activity. Especially, the pesticides which activated with 8-9 mixture gave strong mutagenic activity. 2) With Salmonella typhimurium TA100, the pesticides Monopho, Parathion and Sappiran showed mutagenic activity at $0.5{\mu}g/plate;\;Ometon,\;0.01\; t.tl/plate;Thalonil,\;0.20{\mu}g/plate;\;Prosing,\; 0.20{\mu}l/plate;$ Tedion, Danoton and Phentoate, $1.0\;{\mu}l/plate;\;and\;Captan,\;1.0\;{\mu}g/plate.$ 3) With Salmonella typhimurium TA98, the pesticide Sappiran showed mutagenic activity at $0.02\;{\mu}g/plate;\;Thalonil,\;0.05\;{\mu}g/plate;\;EPN,\;0.05\;{\mu}/plate;\; Phentoate,\;0.10\; {\mu}l/plate;\;Danoton,\;0.50\;{\mu}l/plate;$ Prosing, $ 0.50\;{\mu}g/plate;\;and\;Tedion\;and\;Monopho,\;1.0\;{\mu}l/plate.$ 4) With Salmonella typhimurium TA1535, The pesticides Captan and Danoton showed mutagenic activity at $0.10\;{\mu}g/plate\;and\;0.20\;{\mu}g/plate,\;respectively.$ 5) With Salmonella typhimurium TA1538, The pestides Phentoate showed mutagenic activity at $0.05\;{\mu}l/plate;\;Monopho,\;0.10\;{\mu}l/plate;\;Thalonil,\;0.20 {\mu}g/plate;\;and\;Tedion\;and\;EPN,\;1.0\;{\mu}l/plate.$ 6) The pesticides which commonly showed high mutagenic activity were Thalonil, Phentoate, Parathion and Sappiran. The pesticides Ometon and EPN showed mutagenic activity at only TA100 and TA98, respectively.

• Journal of Food Hygiene and Safety
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• v.29 no.3
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• pp.165-169
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• 2014

Salmonella spp. and Brucella spp. are associated with considerable diseases of both humans and animals. In addition, these microorganisms cause the economic loss in animal farming and food industry. In this study, the disinfection efficacy of a commercial disinfectant, composed to povidone-iodine was evaluated against S. typhimurium and B. ovis. A bactericidal efficacy test by broth dilution method was used to determine the lowest effective dilution of the disinfectant following exposure to test bacteria for 30 min at $4^{\circ}C$. The disinfectant and test bacteria were diluted with hard water (HW) or organic matter suspension (OM) according to treatment condition. On HW condition, the bactericidal activity of the disinfectant against S. typhimurium and B. ovis was 400 and 150 fold dilutions, respectively. On OM condition, the bactericidal activity of the disinfectant was 5 and 20 fold dilutions against S. typhimurium and B. ovis, respectively. As the disinfectant composed to povidine-iodine possesses bactericidal efficacy against animal pathogenic bacteria such as S. typhimurium and B. ovis, the disinfectant solution can be used to control the spread of bacterial diseases.