• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.1181-1184
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• 2011

Total aerobic bacteria, Esherichia coli O157:H7, and Salmonella spp. were examined in commercial liquid pig manures. Commercial liquid pig manures (n=33) were collected from muck joint resource recovery plant at April, June, August, October 2009, Korea. Total aerobic bacteria were incubated at $37^{\circ}C$ for 24-48 hrs, and quantified as a colony-forming unit (CFU) $mL^{-1}$. Analysis of Esherichia coli O157:H7 and Salmonella spp. were followed by Korean Food Standards Codex method. Colony of Salmonella spp. was confirmed by API kit and real time polymerase chain reaction (PCR). Total aerobic bacteria isolated from fermented commercial liquid pig manures ranged from 2.8 to $24.3{\times}10^4\;CFU\;mL^{-1}$. Esherichia coli O157:H7 was not detected, and Salmonella spp. showed the low detection frequency at only 1 sample. This study suggests that continuous monitoring in commercial liquid pig manures is required to improve the agricultural food through management of agricultural land contaminated with liquid pig manures.

• Journal of Microbiology and Biotechnology
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• v.10 no.2
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• pp.227-232
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• 2000

Fresh pine needles were collected and extracted with 95% methanol and the extract was concentrated to determine its antimicrobial activity. The methanol extract had a considerable inhibitory effect on the tested bacteria, such as Esherichia coli 0157;H7, Listeria monocytogenes, Salmonella typhimurium, and Staphylococcus aureus. The methanol extract of pine needles was further fractionated to chloroform, ethylacetate, butanal, and water fractions. Among these four fractions, the butanol and water fractions, which showed a relatively strong inhibitory effect on all of the tested bacteria, were purified and the minimum ingibitory concentration (MIC) was determined for each microorganism. The MIC raged between 25 mg/ml and 45 mg/ml depending on the microorganism. the purified active fractions were applied to sterilized milk as a model food system to define the antimicrobial effectiveness and it was found that the antimicrobial activities in the water fractions were stronger than those in the butanol fractions.

• Clinical and Experimental Pediatrics
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• v.46 no.2
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• pp.143-153
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• 2003

Purpose : Infection with Shiga-like toxin (SLT)-producing Escherichia coli, an emerging human pathogen found particularly in young children under 5 years of age, causes a spectrum of illnesses with high morbidity and mortality, ranging from diarrhea to hemorrhagic colitis and hemolytic uremic syndrome. Host mediators play an important role in the pathogenesis of SLT-I toxicity. The experiments described here were designed to investigate the effect of SLT-I on TNF-${\alpha}$ production and to understand the effect of TNF-${\alpha}$ on GB3 expression. We also further examine the relationship between the Gb3 level and the differential susceptibility of cells to the cytotoxic action of SLT-I. Methods : The effect of purified SLT-1 from E. coli O157 : H7 (ATCC 43890) on tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$) production in Raw264.7 cells was investigated. Many mediators regulate endothelial cell membrane expression of the glycolipid globotriaosyleramide (Gb3), which serves as the toxin receptor, suggesting that the host response to the toxin or other bacterial products may contribute to pathogenesis by regulating target cell sensitivity to the toxins. Therefore, the relationships between Gb3 expression and cytotoxicity against SLT-I on three types of cells were evaluated. Results : Detectable levels of TNF-${\alpha}$ were produced as early as six hours after induction and continued to increase during 48 hours by SLT-I. It was also found that Vero cells and dendritic cells (DC2.4 cells) expressed high levels of Gb3, 83% and 68%, respectively, and that Raw264.7 cells had a low level of Gb3 (29%) and appeared refractory to cytotoxicity against SLT-I. Vero cells and DC2.4 cells expressing high levels of Gb3 were highly susceptible to SLT-I. Furthermore, macrophages showed a resistance to SLT-I cytotoxicity, despite the fact that Gb3 expression was enhanced. Conclusion : These results strongly suggest that the expression of Gb3 is necessary but not sufficient to confer sensitivity of macrophages to SLT-I and further underpin the important role of SLT-I and its Gb3 receptors in the pathogenesis of E. coli O157 infection.

• Journal of Life Science
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• v.17 no.4 s.84
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• pp.482-492
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• 2007

Infection with Shiga-like toxin (SLT)-producing Escherichia coli causes a spectrum of illnesses with high morbidity and mortality. Host mediators play an important role in the pathogenesis of SLT-I toxicity. We here investigated the effect of SLT-I on tumor necrosis $factor-{\alpha}\;(TNF-{\alpha})$ production, effect of $TNF-{\alpha}$ on glycolipid globotriaosyleramide (Gb3) expression, and relationship between Gb3 level and differential susceptibility of cells to SLT-I. In this study, we observed that detectable levels of $TNF-{\alpha}$ are produced 6 hrs after induction and continued to increase during 48 hrs by SLT-I. It was also found that Vero cells and dendritic cells expressed high levels of Gb3, 83% and 68%, respectively, and that macrophages had a low level of Gb3 (29%) and showed refractory to cytotoxicity against SLT-I. Vero cells and dendritic cells expressing high levels of Gb3 were highly susceptible to SLT-I. furthermore, macrophages showed a resistance to SLT-I cytotoxicity, despite the fact that Gb3 expression was enhanced. These results suggest that the expression of Gb3 is necessary, but not sufficient to confer sensitivity of macrophages to SLT-I and further underpin the important role of SLT-I and its receptor, Gb3, in the pathogenesis of E. coli O157 infection.