• 방사선산업학회지
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• 제7권2_3호
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• pp.161-166
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• 2013

The purpose of this study was to investigate the cell proliferating and interleukin-2 producing activity of staphylococcal enterotoxin B by gamma-irradiation. Staphylococcal enterotoxin B was gamma-irradiated with the various doses of 0, 2, 20 and 50 kGy. SDS-PAGE analysis showed that gamma-irradiation caused the sharp decrease of the content of staphylococcal enterotoxin B and the effect was irradiating dose-dependent. Non-irradiated staphylococcal enterotoxin B increased the cell proliferation of splenocytes isolated from female Balb/c mouse, whereas 2 kGy-irradiated toxin significantly decreased the activity. 20 and 50 kGy-irradiated staphylococcal enterotoxin B was no effect. A similar effect on the interleukin-2 production of mouse splenocytes was observed with non-irradiated and irradiated staphylococcal enterotoxin B. It was considered to be due to the decrease of the antigenicity of staphylococcal enterotoxin B by gamma-irradiation. Therefore, these results suggest that gamma-irradiation can be effective for the decrease of the antigenicity of staphylococcal enterotoxin B as superantigen.

• Food Science and Biotechnology
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• 제15권2호
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• pp.232-237
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• 2006

Bacillus cereus group comprising B. cereus, B. thuringiensis, and B. mycoides was differentiated by polymerase chain reaction (PCR) and colony morphology. Prevalence of B. cereus group in rice and distribution of enterotoxin genes were determined as possible food poisoning agents. PCR using primers targeted for gyrB and cry genes could distinguish B. thuringiensis from B. cereus, and B. mycoides was differentiated by rhizoid morphological characteristics on nutrient agar. Among 136 rice and their processed products, prevalence of B. cereus group was 40%. B. cereus group consisted of 54 B. cereus, 11 B. thuringiensis, and 1 B. mycoides. Major isolates were B. cereus, with B. thuringiensis detected up to 10% among edible rice tested. Five enterotoxin genes, hbl, nhe, bceT, entFM, and cytK, were broadly distributed among B. cereus group, especially in B. cereus and B. thuringiensis. Prevalence of B. cereus group in rice and enterotoxin distribution suggest B. thuringiensis and B. cereus are toxigenic strain that should be controlled in rice and its products.

• Food Science and Biotechnology
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• 제17권4호
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• pp.761-765
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• 2008

Bacillus cereus causes two different types of food poisoning syndromes: diarrhea and emesis. The diarrheal syndrome is attributed to various enterotoxins, including nonhemolytic enterotoxin, hemolytic enterotoxin, and enterotoxin-T, whereas the emetic syndrome is caused by the dodecadepsipeptide toxin cereulide. A multiplex polymerase chain reaction (PCR) assay was developed to rapidly detect and identify B. cereus strains. Three primer pairs specific to regions within genes encoding nonhemolytic enterotoxin (nheA), molecular chaperonin (groEL), and cereulide synthetase (ces) were used to identify and differentiate between the enterotoxin-producing and emetic toxin-producing B. cereus strains. The cereulide-producing emetic B. cereus showed 3 PCR products of 325, 405, and 685 bp for the groEL, ces, and nheA genes, respectively, whereas the enterotoxin-producing B. cereus showed 2 PCR products without a ces gene specific DNA fragment. Specific amplifications and differentiations by multiplex PCR assay were obtained using 62 B. cereus strains and 13 strains' of other bacterial species. The detection limit of this assay for enterotoxin-producing strain and emetic toxin-producing strain from pure cultures were $2.4{\times}10^1$ and $6.0{\times}10^2\;CFU/tube$, respectively. These results suggest that our multiplex PCR method may be useful for the rapid detection and differentiation of B. cereus strains in foods.

• 한국식품영양학회지
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• 제27권2호
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• pp.213-218
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• 2014

적리를 동반하는 돼지 분변에서 용혈성 균주를 분리 동정한 후, 장 독소 생성 유 무 및 항생제 감수성 시험을 수행하였다. 분리된 용혈성 균주 B. cereus BY06의 gyrB 유전자 염기서열을 분석한 결과, B. cereus와 99% 유사성을 나타내었다. PCR법에 의한 장 독소 유전자 검출 시험에서 B. cereus BY06는 장 독소 분비 양성으로 판정됨에 따라 설사형 식중독 균임이 확인되었다. B. cereus BY06를 이용한 항균제의 감수성 시험 결과, penicillin G에는 내성을 나타낸 반면 cephalothin, vancomycin, clindamycin, fusidic acid, gentamicin, ciprofloxacin, tetracycline 및 rifampin에 대하여 감수성을 나타냈다. 본 연구를 통해 돼지 분변에서 분리된 B. cereus 균주는 설사를 유발하는 장 독소를 분비하며, penicillin G에 대한 내성을 확인하였다.

• Food Science and Biotechnology
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• 제17권4호
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• pp.824-828
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• 2008

Effect of various temperatures on enterotoxin production of Bacillus cereus 4 different cereal grains (brown rice, glutinous rice, barley, and Job's tear) was studied. When B. cereus was inoculated to 4 grains, no toxin was detected within 24 hr at 20 and $25^{\circ}C$ although the population reached approximately 8-10 log CFU/g. However, enterotoxin was detected in all samples above $30^{\circ}C$. When the temperature was increased to $35^{\circ}C$, toxin production was observed in the range of 6.11 and 6.26 log CFU/g on brown rice and glutinous rice, respectively. At $40^{\circ}C$, toxin production was detected after 6 hr with the lowest bacterial population of 5.32 and 5.04 log CFU/g, whereas enterotoxin was produced in the range of 6.86 and 7.77 log CFU/g on barley and Job's tear at $40^{\circ}C$. Different types of food affected enterotoxin production of B. cereus. These results suggest that enterotoxin production was more significantly regulated in incubation temperatures than the number of B. cereus.

• 한국식품위생안전성학회지
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• 제6권2호
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• pp.89-93
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• 1991

사람에서 분리되는 Staphylococcus aureus 의 병원성과의 관계를 검토할 목적으로 건강인과 환자의 손에서 Staphylococcus aureus를 분리하여 병원성과 관련된 몇가지 특성과 enterotexin 산생성을 조사한 바 다음과 같은 결론을 얻었다. 1. Staphylococcus aureus의 분리빈도는 건강인에서 17.7% 환자에서 14.0%로 나타났다. 2. 공시한 61주는 면양혈액비지상에서 β용혈성이 67.2% α용혈성이 32.8%로서 분리균 모두가 용혈성을 나타내었고 mannitol 분해 , lecithinase, TNase 및 DNase 시험에서 공시한 전 균주가 양성반응을 보였다. 3. Ushioda 등의 방법에 의하여 coagulase type을 분류한 바 공시한 46주 가운데 91.3%가 형별되었고, 이들 중 type VII(38.4%)과 III(26.0%)가 비교적 높은 분포를 나타내었다. 유래별로 보면 건강인 유래주는 22주 중 type VII(12주)이 가장 많았고, 화자 유래주는 24주 중 type III(9주) 및 II(6주)가 높은 분포를 보였다. 4. Enterotoxin 산생율은 46균주 중 52.2%였고 분리된 enterotoxin type은 C(50.0%), B(37.5%) 및 A (12.5%) 였다. 유래별로 보면 건강인 유래주는 type C와 B로 환자 유래주는 type B,A 및 C로 분류되었다. 5. Coagulase type에 따른 enterotoxin 산생율은 type II, III 및 VII 의 순으로 각각 100%, 75%, 및 39.1% 였다. 이들 가운데 coagulase type II는 enterotoxin type B 및 C를 type VII은 type C를 산생하는 균이었고, 대체적으로 건강인 유래주는 enterotoxin type C를 환자유래균은 type B를 생성하는 균이 많은 것으로 인정되었다.

• 한국동물위생학회지
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• 제23권4호
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• pp.313-320
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• 2000

Staphylococcus aureus is a causative pathogen of bovine mastitis. It is recognized as a common pathogen in human and animal and specially enterotoxin-producing strain of S aureus is a common cause of staphylococcal food poisoning in human. Various food originated raw milk, cheese, butter produced from mastitic cow causes staphylococcal food poisoning. It is difficult to treat the staphylococcal mastitis because of increasing resistance by using overdose of antibiotics. This study was conducted to investigate the enterotoxin-production and coagulase serotypes of S aureus in Chonnam province for 6 month, 1999. Also we studied the antibiotic resistant pattern with 14 types against isolates. 18(10.1%) S aureus were isolated from 178 raw milk samples in seven farms. and 8 strains(38%) were isolated in 21 raw milk samples which was below 500,000 somatic cells. We identify that 7(87.5%) of 8 isolates and 15(83.3%) 18 isolates produce enterotoxin. Their enterotoxin serotype was type B(66.7%), type A(33.3%) and type C(13.3%). Also 2 strains of isolates was positive to the type A and B. Coagulase serotype of isolates was 2, 3, 4, 7, and 8. Most stains(70.6%) were serotype 2. And most strains(17 isolates, 94.4%) except one isolate was multiple resistant to the tested antibiotics.

• Journal of Microbiology and Biotechnology
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• 제10권1호
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• pp.86-90
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• 2000

We have earlier reported on the cloning and identification of bft-k from an enterotoxigenic strain of Bacteroides fragilis 419, which was isolated from the blood of a Korean patient who suffered from systemic infections [4,5]. The bft-k gene encodes a 397-amino-acids metalloprotease enterotoxin, and the protein has been identified as a new isoform of B. fragilis enterotoxins (BFTs), which are cytopathic to intestinal epithelial cells to induce fluid secretion and tissue damage in ligated intestinal loops [4, 6, 18, 20]. This report describes the cloning and sequencing of the enterotoxin pahogenicity islet of B. fragilis 419 which contains the bft-k gene. the cloned enterotoxin pathogenicity islet was found to have 6,045 bp in length and to contain 120bp direct repeats near its end. In the pathogenicity islet, in addition to the BFR-K, two putative open reading frames (ORFs) were identified; (1) the t-3 gene encoding a 396-amino-acids protein of a putative metalloprotease; (2) the third gene encoding an ORF of a 59-amino-acids protein, whose function has not yet beenn characterized. The expression of the t-3 gene in B. fragilis 419 was verified by western blot analysis.

• 한국식품위생안전성학회지
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• 제3권2호
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• pp.75-81
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• 1988

본 실험은 Staphylococcus aureus 로부터 생성되는 enterotoxi B 의 분리 및 정제를 위하여 각종 분리방법을 비교 조사하였다. 배지로부터 Entrotoxin B를 추출하는 방법중 Amberlite CG-50 수지가 가장 간편하고 빠른 방법이었고 CM 수지는 Amberlite 수지에 비해 용출력이 떨어졌으며 분리할 수 있는 toxin의 양은 적었으나 정제도에 있어서는 약 75%로 toxin을 분리하는 처음 단계로서는 높은 편이었다. CM column을 Gradient 용출법으로 사용했을 때에는 하나의 column을 사용해 분리한 분리물 중 정제도가 85%로 가장 높았고, 용출 buffer의 농도 폭을 넓히는 것이 정제도를 높이기 위한 바람직한 방법이었다. 이 실험에 사용한 Sephadex G-50 , 75, 100, Sephacryl, Ultro gel 등의 gel filtration 방법 중 Ultro gel 에 의한 분리방법이 정제도에 있어서는 가장 우수했으며, 이온 교환 수지를 먼저 사용한 분리물에서는 모두 90% 이상의 toxin을 얻을수 있었지만, 한번의 분리도 거치지 않은 배지는 분리도와 정제도에서 현저히 떨어졌고, Sephadex G-50 은 gel colunm중 정제도가 가장 낮았다. FPLC는 위의 분리 ·정제 방법중 가장 빠른 방법이며, 적은 양의 시료로도 측정이 가증하였고, 정제도는 95% 이상이었다.

• 대한미생물학회지
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• 제17권1호
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• pp.35-41
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• 1982

Enterotoxigenk E. coli is one of the major causative agents of the infantile diarrhea and traveler's diarrhea. The heat-labile enterotoxin is thought to be a virulence factor in the pathogenesis of the diarrhea and to be a marker for identification of the enterotoxigenic E. coli from non pathogenic E. coli. Therefore knowledge about the heat-labile enterotoxin is essential not only for understanding the pathogenesis but also for the diagnosis of the diarrhea. However the in-vitro heat-labile enterotoxin production is reported to be greatly affected by the cultural condition. In this regards, this study was designed to know the optimal conditions for the production of the heat-labile enterotoxin by assaying the permeability factor in the 18 hours culture supernatant of E. coli 08K25(B2) H9 and of E. coli 015 H11. Results obtained were summerized as follows: 1. Amounts of heat-labile enterotoxin produced were greater at initial pH 8.5 than at 7.0 of CYES-2 broth culture. However, the bacterial growth itself was more abundant at 7.0 than at 8.5. 2. Heat-labile enterotoxin per unit volume of culture supernatant was greater at shaking culture than at standing culture condition, but ratio of the enterotoxin produced over the unit mass of E. coli calculated was greater at standing culture than shaking culture condition, indicating that the greater yields of the toxin produced at shaking culture was due to increase in E. coli cell mass compared to the standing culture condition: 3. The enterotoxin produced in the lincomycin(128 microgram/ml) supplemented media was 5 or 11 times greater on the basis of enterotoxin per unit mass of E. coli, compared to the lincomycin-non-supplemented media, indicating that lincomycin itself increases the enterotoxin production. 4. Treatment of 18 hours culture of E. coli with polymyxin B(0.2 mg/ml) for 1 hour increased the yields of enterotoxin amounting to 2 or 5 times of the non-treated control cultures.