• Food Quality and Culture
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• 제3권1호
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• pp.34-39
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• 2009

This study assessed the efficacy of aqueous chlorine dioxide ($ClO_2$) and commercial chlorine sanitizer in terms of its ability to eliminate Listeria monocytogenes, Salmonella Typhimurium, and Escherichia coli O157:H7 on radish sprouts (Raphanus sativus L.). Radish sprouts were inoculated with a cocktail containing one each of three strains of three different foodborne pathogens, then treated with distilled water (control) or chemical sanitizers (100 ppm commercial chlorine, and 50, 100, 200 ppm $C1O_2$) for 1, 5, and 10 min at room temperature ($22{\pm}2^{\circ}C$). Populations of S. Typhimurium, E. coli O157:H7 and L. monocytogenes were counted at 4.64, 6.05, and 4.29 log CFU/g, respectively, after inoculation. Treatment with water did not significantly reduce the levels of any of the three foodborne pathogens. The levels of all three pathogens were reduced by treatment with chemical sanitizers; however, the observed levels of reduction of E. coli O157:H7 and L. monocytogenes were not significant as compared with the controls. The levels of the three pathogens were reduced most profoundly when treated for 10 min with 200 ppm of $C1O_2$, and the reduction levels of S. Typhimurium, E. coli O157:H7, and L. monocytogenes were 1.17, 1.63, and 0.96 log CFU/g, respectively. When chemically injured cells were investigated using SPRAB for E. coli O157 :H7 and by selective overlay methods for S. Typhimurium and L. monocytogenes, respectively, it was noted that commercial chlorine sanitizer generated more numbers of injured pathogens than did $C1O_2$. These data indicate that $C1O_2$ treatment may prove useful in reducing the numbers of pathogenic bacteria in radish sprouts.

• 한국환경성돌연변이발암원학회:학술대회논문집
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• 한국환경성돌연변이발암원학회 2001년도 Korean Environmental Mutagen Society
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• pp.157-157
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• 2001

• Journal of Microbiology and Biotechnology
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• 제23권12호
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• pp.1708-1716
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• 2013

Conventional molecular detection methods cannot distinguish between viable and dead Escherichia coli O157 cells. In this study, the loop-mediated isothermal amplification (LAMP) method combined with propidium monoazide (PMA) treatment was developed to selectively detect viable E. coli O157 cells. Four primers, including outer primers and inner primers, were specially designed for the recognition of six distinct sequences on the serogroups (O157) of the specific rfbE gene of the E. coli O157 genome. PMA selectively penetrated through the compromised cell membranes and intercalated into DNA. Amplification of DNA from dead cells was completely inhibited by $3.0{\mu}g/ml$ PMA, whereas the DNA derived from viable cells was amplified remarkably within 1 h by PMA-LAMP. Exhibiting high sensitivity and specificity, PMA-LAMP is a suitable method for evaluating the inactivation efficacy of slightly acidic electrolyzed water in broth. PMA-LAMP can selectively detect viable E. coli O157 cells. This study offers a novel molecular detection method to distinguish between viable and dead E. coli O157 cells.

• 한국식품저장유통학회지
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• 제5권3호
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• pp.286-291
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• 1998

4종류의 식중독세균(Escherichia coli O157:H7, Listeria monocytogenes, Staphylococcus aureus 196E, Salmonella typhimurium)에 대하여 녹차 물추출물에 의한 항균작용을 조사하였다. 각 식중독세균을 tryptic soy broth(TSB)에 약 $10^{5}$CFU/ml 정도 되게 접종하여 35$^{\circ}C$에서 30시간 배양하였다. 세균의 배양중 대수증식기의 중기 혹은 말기에 녹차 물추출물을 0-2%(w/v)의 농도로 첨가하였을 때 증식억제 정도를 생균수 변화로서 비교하였다. 식중독세균의 증식은 첨가한 녹차 물추출물의 농도에 비례하여 억제되었으며 대수증식기 말기의 세균이 중기의 세균에 비하여 녹차 물추출물에 대한 내성이 컸다. Gram 양성균(L. monocytogenes, S. aureus)의 경우가 Gram 음성균(E. coli O157:H7, S. typhimurium)에 비하여 녹차 물추출물에 의한 억제효과는 월등히 컸다. 녹차 물추출물에 의한 증식억제 효과의 크기는 S. aureus, L. monocytogenes, E. coli O157:H7의 순이었으며 S. typhimurium에서 가장 강한 내성을 나타내었다.다.

• Journal of Dairy Science and Biotechnology
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• 제40권4호
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• pp.151-162
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• 2022

Although many developed countries (USA, Canada, and several EU countries) allow raw milk cheese to be aged more than 60 days, these countries have strict standards for the aging conditions, such as temperature, of raw milk cheese. Spiking experiments were conducted with Camembert cheese made from raw milk, to assess the microbiological safety of raw milk cheese aged for more than 60 days. We spiked Escherichia coli O157:H7 into raw milk with different inoculation levels (high, medium, and low). Camembert cheese was prepared from the inoculated raw milk, then aged in an incubator for up to 9 weeks (63 days). There were no significant differences in pH and water activity (aW) between uninoculated cheese and cheese samples inoculated with E. coli O157:H7 (p<0.05). The pH and aWof the Camembert cheese decreased throughout the storage period. In conclusion, E. coli O157:H7 did not affect the pH and aW of the cheese samples. Cell counts were conducted every week using the agar-plating method. Inoculated cells were completely eliminated, especially in Camembert cheese, after 60 days, and the reduction rate of cells was much faster in Camembert cheese.

• 한국식품과학회지
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• 제50권4호
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• pp.414-419
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• 2018

병원성 대장균 O157:H7은 식중독 사고를 일으키는 주된 원인균으로서 항생제 내성 문제를 극복하기 위해서는 병원성 대장균 O157:H7을 제어하기 위한 새로운 방법이 개발되어야 한다. 따라서 본 연구에서는 식물화학물질을 스크리닝하여 병원성 대장균 O157:H7의 부착에 주된 역할을 하는 LEE 오페론의 발현을 감소시키는 물질을 찾고자 하였다. 스크리닝을 통해 선발된 식물화학물질 중 다이오스민은 사람 결장 상피세포 부착능을 3.62배 감소시킴으로써(p<0.01) 양성대조군으로 사용된 미리세틴과 유사한 정도의 효과를 나타냈다. 생물막 형성에 있어서는 다이오스민 처리 시 표현형이 25.6% 감소하여 유의적 차이가 확인되었고(p<0.05), curli 유전자의 발현 역시 미리세틴 처리 때보다 1.57-2.60배 더 유의미하게 감소하는 것으로 나타나 양성대조군보다 더 좋은 효과를 보였다. 한편 다이오스민은 병원성 대장균 O157:H7의 생장에는 아무런 영향을 미치지 않는 것으로 나타나 내성 발생률이 저감화된 새로운 항미생물제재로서 사용 가능하리라 판단된다.

• 한국미생물학회:학술대회논문집
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• 한국미생물학회 2008년도 International Meeting of the Microbiological Society of Korea
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• pp.135-135
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• 2008

Various biosensors were evaluated for identifying and detecting foodborne pathogens in a rapid and effective manner. First, five strains of Escherichia coli and six strains of Salmonella were identified using Fourier transform infrared spectroscopy and a statistical program. For doing this, lipopolysaccharides (LPSs) and outer membrane proteins (OMPs) were extracted from a cell wall of each bacterial strain. As a result, each strain was identifed at the level of 97% for E. coli and 100% for Salmonella. Second, E. coli O157:H7, S. Enteritidis, and Listeria monocytogenes were identified by multiplex PCR products from four specific genes of each bacteria using a capillary electrophoresis (CE). Also, ground beef for E. coli O157:H7, lettuce for S. Enteritidis, and hot dog for L. monocytogenes were used to determine the possibility of detecting pathogens in foods. Foods inoculated with respective pathogen were cultivated for six hours and multiplex PCR products were obtained and assessed. The minimum detection levels of tested bacteria were <10 cells/g, <10 cells/g, and $10^4$ cells/g for E. coli O157:H7, S. Enteritidis, and L. monocytogenes, respectively. Third, it was possible to detect S. Typhimurium in a pure culture and lettuce by a bioluminescence-based detection assay using both recombinant bacteriophage P22::luxI and a bioluminescent bioreporter. In addition, bacteriophage T4 was quantitatively monitored using E. coli including luxCDABE genes.

• 한국미생물·생명공학회지
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• 제27권5호
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• pp.419-425
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• 1999

Prophylactic effects of Bifidobacterium longum HY8001, Korean isolate, against Escherichia coli O157:H7 and Salmonella typhimurium DT104 enteric infection were examined at four groups of specific pathogen free(SPF)-ICR mouse for each pathogen. B. longum HY8001+B. typhimurium DT104+B. longum HY8001(BL+ST+BL) group and B. longum HY8001+E. coli O157:H7+B. longum HY8001(BL+E+BL) group were fed with B. longum HY8001 before and after E. coli O157:H7 or s. typhimurium DT104 challenge, while B. longum HY8001+S. typhimurium DT104(BL+ST) and B. longum HY8001+e. coli O157:H7(BL+E) groups were fed with B. longum HY8001 only before E. coli O157:H7 or S. typhimurium DT104 challenge. E. coli O157:H7(E) and S. typhimurium DT104(ST) groups were challenged with each pathogen without B. longum HY8001 administration and control groups were administered with phosphate buffered solution(PBS). After the oral administration with B. longum HY8001(109cfu), th emice were challenged with E. coli O157:H7(2$\times$1010cfu) or S. typhimurium DT104(108cfu) and the mortality rate and the fecal shedding of challenged pathogen were also examined define the reactivity of the B. longum HY8001. Production of toxin neutralizing substance(s) of B. longum HY8001 was determined by cell cytotoxicity assay using Vero cells. Fecal shedding of th eS. typhimurium DT104 was significantly decreased in BL+ST+BL group fed with B. longum HY8--1 before and after challenge(p<0.05), while the fecal shedding s of S. typhimurium DT104 in BL+ST and St groups remained more than 106cfu. the protective effect of the B. longum HY8001 against E. coli O157:H7 was significantly high only in BL+E+BL group fed with b. longum Hy8001 before and after E. coli O157:H7 challenge from the result of fecal E. coli O157:H7 isolation rate, mortality rate, and intestinal contents culture to detect E. coli O157:H7. the mortality rate of the BL+e and E groups. The cytopathic effect (CPE) of the Vero cytotoxin (Shiga like toxin I & II) in Vero cell was neutralized in B. longum HY8001 culture supernatant added wells which indicate the presence of soluble Vero cytotxin neutralizing substance(s) in B. longum HY8001 culture suprnatant.

• 대한생식의학회:학술대회논문집
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• 대한불임학회 2003년도 제45차 추계학술대회
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• pp.157-157
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• 2003

• Tuberculosis and Respiratory Diseases
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• 제59권1호
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• pp.30-38
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• 2005

연구배경 : Arsenic trioxide($As_2O_3$, 비소 삼산화물)는 급성전 골수성백혈병의 효과적인 치료제로 이용되고 있고, 비소세포폐암을 비롯한 여러 고형종양세포에서 세포 고사를 유도하나 백혈병에 비해 상대적으로 높은 농도가 필요하여 실제적인 치료에 제한이 있어왔다. Sulindac은 COX-2 억제, 암세포 성장의 억제 및 세포 고사 유도를 기전으로 하는 항암효과가 있고, 다른 화학요법이나 방사선치료의 반응성을 증가시키는 것으로 알려져 있다. 저자들은 NCI-H157 폐암세포주에서 $As_2O_3$와 sulindac의 병합요법이 Fas/FasL 신호전달계의 활성화와 caspase 단백질 활성화 의해 세포고사가 유도되었음을 보고한 바 있다. 이 연구의 목적은 이러한 경로 이외에 다른 기전유무를 밝히는데 있다. 방 법 : 세포 독성은 MTT 방법으로 구하였고, HRP 방법을 이용해 ROS를 직접 측정하였다. 세포고사의 형태학적 특성을 보기위해 핵산염색과 관련된 단백질의 발현을 확인하였다. 또한 미토콘드리아의 기능변화를 보기 위해 미토콘드리아의 막전위차를 측정하였고, anti-cytochrome c와 Bcl-2 family 단백질들의 발현 양상을 western blotting을 통해 관찰하였다. 결 과 : 단독요법에 비해 병합요법시에 생존율의 의의 있는 감소를 보였다. 이러한 생존율은 항산화제를 전처리 한 경우 농도 의존적으로 회복됨을 관찰할 수 있었다. ROS의 생성은 병합요법시에 대조군에 비해 의의 있게 증가하였고, 이러한 현상은 항산화제 전처리군에서 감소된 소견을 보였다. 또한 병합요법시 핵산염색에 의해 여러조각의 분절된 형광절편과 caspase 3, PARP의 활성을 통해 세포고사가 유도되었음을 확인하였고, 항산화제 전처리군에서 상쇄됨을 관찰하였다. JC-1 염색 후 형광현미경을 통한 미토콘드리아 막전위차에 미치는 영향은 병합처리군에서 녹색형광으로의 변화가 보였고 항산화제 전처리군에서 소실됨을 확인하였다. 또한 병합요법시의 cytochrome c의 세포 질내의 증가와 미토콘드리아내의 감소가 관찰되었고, Bax의 증가, Bid와 Bcl-xL의 발현감소를 확인할 수 있었으며 이러한 현상은 항산화제 전처리군에서 소실됨을 보였다. 결 론 : NCI-H157 폐암세포주에 $As_2O_3$와 sulindac의 병합 요법은 ROS생성과 미토콘드리아 기능변화를 통해 세포고사가 유도되었다.