• 한국식품과학회지
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• 제20권6호
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• pp.856-861
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• 1988

본 실험은 Staphylococcus aureus의 한 균주로부터 A와 C, 두 종류의 toxin이 동시에 생성될 때 이들의 동시분리를 위하여 각종 분리방법을 연구하였다. 혼합된 toxin A와 C는 CM-column chromatography를 이용하여 pH-gradient법으로 용출했을 때 2개의 분획이 나타났으나 서로 완전히 분리되지 않아 다량의 서로 다른 toxin이 함유되어 있었고 Sephadex G-75, Sephacryl S-300, 그리고 ultro gel을 사용한 gel filtration에서는 하나의 분획을 나타내 상호분리가 불가능 하였으며 정제도와 분리도에서 가장 뛰어난 gel column을 이용한 FPLC도 toxin A와 C를 상호분리할 수 없었다. 그러나 CM-column을 이용한 FPLC에서는 enterotoxin A는 pH 6.8에서 그리고 enterotoxin C는 pH 8.6에서 각각 분리되었으며, immunodiffusion test 결과 enterotoxin A의 분획에서는 toxin C가 전혀 검출되지 않았고 enterotoxin C의 분획에서도 toxin A가 검출되지 않았다. 용출방법에 있어서는 CM-column을 이용한 FPLC에서 pH-stepwise법이나 pH-gradient법으로 enterotoxin A와 C type을 쉽게 동시에 분리할 수 있었다.

• 한국식품영양학회지
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• 제13권1호
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• pp.1-5
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• 2000

Detection for heat-labile enterotoxin(LT) of enterotoxigenic Escherichia coli(ETEC, EC81, O148:H28) and enterotoxin of enterotoxigentic Clostridium perfringents type A(CP, NCTC8238, Hobbs serotype 2) by use of a polymerase chain reaction (PCR) assay were positive reaction, which using LT gene-specific primers of ETEC with a detection limit equivalent from 100ng/${\mu}\ell$ to 1 pg of a DNA fragment of 417-bp in EC81 and enterotoxin gene-specific primers of CP with a detection limit equivalent from 100ng/${\mu}\ell$ to 10pg of a DNA fragment of 364-bp in NCTC8238. Detection for a LT gene of ETEC highly appeared 10-fold sensitivity than an enterotoxin gene of CP.

• 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.

• 한국식품과학회지
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• 제23권2호
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• pp.150-156
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• 1991

발효 소세지의 제조 중 staphylococcal enterotoxin A의 생성에 미치는 첨가제(Glucono delta Lactone, starter culture 및 NaCl)의 효과를 조사하기 위하여 본 실험을 실시하였다. GdL의 첨가량은 높아짐에 따라(0, 0.25, 0.50 및 0.75%) 현저히 enterotoxin 생성량은 줄어들었다(p<0.01). Starter culture(L. plantarum)는 $10^6\;cells/g$수준으로 접종되어 졌는데 0.5% GdL이 첨가되지 않았을 때 starter culture 처리구와 무처리구에서 40 ng/10g과 80 ng/10g을, 그리고 0.5% GdL 첨가되었을 때 starter culture 처리구와 무처리구에서는 최대 50 ng/10g과 30 ng/10g를 생성하여 starter culture의 enterotoxin 생성억제 효과를 보였다. 또한, NaCl은 2.7%와 1.7% 처리구에서 2.7% NaCl 처리가 오히려 더 많은 enterotoxin을 생성 하였다.

• Journal of Microbiology and Biotechnology
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• 제17권3호
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• pp.461-467
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• 2007

Staphylococcus aureus strains are important foodborne pathogens that produce various toxins. To evaluate the risk of the enterotoxins, four S. aureus strains from kimbap and two clinical samples were isolated and identified, and their expression of the enterotoxin genes were analyzed using a reverse transcription real-time PCR. Various enterotoxin genes were detected, including sea, seg, seh, sei, sen, seo, and sem, where each isolate contained one or two. When the mRNA detection of the enterotoxin genes was analyzed using a reverse transcriptase PCR, various levels of expression were found depending on the species and enterotoxin gene. Therefore, it is reasonable to suggest that the poisoning risk of S. aureus can be effectively evaluated based on the gene expression at the mRNA level.

• 대한미생물학회지
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• 제20권1호
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• pp.55-63
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• 1985

Phosphate, ammonia, glucosamine, glucose, pyruvate, succinate, fumarate, malate and acetate were examined for their ability to control the heat-stable enterotoxin (ST) production in succinate salts medium or in M9 medium. The results obtained were summerized as follows. 1. When the initial phosphate concentration was adjusted to 1.0mM, ST production was decreased to 80u/ml or less. But when the initial phosphate concentration was adjusted to 64mM or 100mM, enterotoxin production was 320u/ml. 2. When the initial ammonia concentration in the medium was adjusted to 1.0mM, no ST production and cell growth were observed. But when ammonia concentration was adjusted to 10mM, 19mM, 38mM or 76mM, enterotoxin production was 320u/ml. 3. Among carbon sources, glucosamine, glucose, pyruvate, succinate, fumarate, malate and acetate, acetate supported the highest specific production (928 unit/O.D.) of heat-stable enterotoxin. From this results, we could assume that heat-stable enterotoxin production is controlled by stringent control mechanism. 4. When the pH of the succinate salts medium was kept between 6.2 to 6.5, no heat-stable enterotoxin production was observed, but when the pH of the medium was kept between pH 6.2 to 6.5, 267 unit/O.D. of heat-stable enterotoxin was produced. 5. Glucose inhibited the heat-stable enterotoxin production and the mechanism was assumed due to its capacity to lower the pH of the medium during catabolysis and its high metabolic energy.

• 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.

• 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.

• 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.

• 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.