• 한국동물위생학회지
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• 제21권2호
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• pp.117-126
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• 1998

This study was performed to investigate the immunogenicity of autogenous E coli vaccines and their preventive effects on diarrhea in suckling piglets. Autogenous E coli live and killed vaccines were made from the E coli strains isolated from piglets showing diarrhea in field. In group I, pregnant sows were administered with live and killed vaccines at 4 and 2 weeks before parturition, respectively, Killed vaccines were administered twice to pregnant sows at 4 and 2 weeks before parturition in group II, and saline instead of autogenous E coli vaccines was administered to pregnant sows in group III for the control. After parturition, antibody titers in colostrum and milk from sows, incidence of diarrhea in suckling piglets, and immunoreactivity in the ileum of piglets from each treatment group were examined. The results were as follows ; 1. Sixty-two strains of E coli were isolated from suckling piglets with diarrhea. Of the strains, K88 pilus and K99 pilus antigens were identified in 6(9.8%) and 4(6.5%), respectively. Molecular weights of K88 and K99 pilus were 27,500 and 18,500 daltons, respectively. 2. Antibody titers in colostrum from sows after parturition were 1 : 512 to 1 : 1,024 in group I, 1.256 to 1.512 in group II, and 1 : 4 to 1 : 16 in group III. 3. The incidences of diarrhea In suckling piglets of group I, II and III were 3.3%, 9.4% and 21.4%, respectively. 4. When the immunoreactivity in the ileum of piglets from each group was examined, the proportion of IgG-immunoreactivity cells in group I or II was higher than that in group III. In conclusion, administration of autogenous E coli vaccines to pregnant sows before parturition can be an effective way to prevent diarrhea in suckling piglets.

• 한국어류학회지
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• 제19권2호
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• pp.83-87
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• 2007

어류 에드워드감염증에 대한 예방 재조합 ghost 백신을 개발하기 위한 연구의 일환으로 어류 병원성 세균인 Edwardsiella trada를 대상으로 플라스미드 형질전환을 실시하고 형질전환 안정성을 평가하였으며, 형질 도입된 재조합 ghost 세균의 E-lysis 유전자 발현을 분석하였다. E. tarda를 대상으로 한 ghost 유도는 대장균에 비해 상대적으로 장시간의 반응 시간이 요구되며 lysis의 개시가 지연된 점을 고려 시 발현된 E protein의 용해 능력 또는 E-gene의 전사발현 양이 E. tarda에서 다소 약화되는 것으로 나타났다. 그러나 대장균에 비해 ghost 유도 속도가 다소 낮음에도 불구하고 반응이 완성되었을 시점에서의 E. tarda의 ghost 효율은 대장균과 전혀 차이가 없이 99.99% 이상의 유도효율을 나타내었다.

• BMB Reports
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• 제32권5호
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• pp.436-439
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• 1999

Shigella sonnei is an important cause of human enteric infections. S. sonnei KNIH104S was previously reported to be isolated from Korean shigellosis patients. We cloned a 2.8-kb KpnI fragment containing the recA gene encoding a recombinase from the chromosomal DNA of S. sonnei KNIH104S. This recombinant plasmid was named pRAK28. E. coli HB101, a recA mutant, cannot grow on Luria-Bertani medium in the presence of the alkylating agent methylmethane sulfonate, however, E. coli HB101 harboring pRAK28 was found to grow on this medium. As far as we know, we are the first to sequence the recA gene from S. sonnei. This gene is composed of 1062 base pairs with an ATG initiation codon and a TAA termination codon. Nucleotide sequence comparison of the S. sonnei recA gene exhibited 99.7% and 99.5% identity with those of S. flexneri and E. coli, respectively.

• 대한수의학회지
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• 제30권3호
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• pp.287-295
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• 1990

The purpose of this study was the examination for presence of pilus antigen, O serogroups, colicin production, antibiotic susceptibility and plasmid profiles among E coli isolated from diarrheal piglets and fattening pigs in Taegu province. Of 145 E coli isolated, 98 strains (67.4%) possesed pilus antigens which belonged to either K88 (47.6%), K99 (11.7%) or 987P (8.3%) types. Fifty-nine strains (40.7%) were classified into tenO serogroups and their types were O8 (22.0%), O20(16.9%), O141(15.3%), O9(10.2%), O45(10.2%), O139(8.5%), O064(6.8%), O149(5.0%), O157(3.4%), and O115(1.7%). Thirty-three strains (22.8%) were colicinogenic and 6 strains (4.1%) were hemolytic. One hundred and thirty-nine strains (95.9%) of 145 E coli isolates were resistant to ampicillin, chloramphenicol, gentamicin, kanamycin, streptomycin, tetracycline, rifampicin and nalidixic acid, alone or in combination thereof. Ninety strains (64.7%) of 139 drug resistant strains carried R factor (R) which were transferable to the recipient by conjugation. In gel electrophoresis for the isolation of plasmid DNA, the number of plasmid DNA band varied from 2 to 11 in 16 E coli with pilus antigen. It's molecular weight ranged from 1.0 to 60.0 megadalton.

• 한국식품저장유통학회지
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• 제17권2호
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• pp.301-306
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• 2010

본 연구에서는 계육 창상부위의 원인이 되는 세균을 동정하였다. 계육의 등과 다리 창상 부위로부터 무작위 선별법을 통해 총 10주의 균주를 분리하였다. 순수 분리 배양된 균주의 세포막 지방산 조성 분석 결과, 5 균주가 높은 유효성을 지녔으며, Shigella sonnei, Proteus mirabilis, Escherichia coli로 동정되었다. 또한 16S rRNA sequence를 실시한 결과, 동정된 균주는 Shigella sonnei(99%), Proteus mirabilis(99%) 그리고 Escherichia coli(99%)와 높은 염기서열 상동성을 나타냈다. 따라서 본 연구에서 조사된 계육의 등과 다리 부위 주요 창상 원인균은 Shigella sonnei, Proteus mirabilis, Escherichia coli인 것으로 밝혀졌다.

• 대한수의학회지
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• 제27권2호
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• pp.259-267
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• 1987

Enterotoxigenic E. coli (ETEC) cause an acute diarrhea (white scour) in both animals and humans. The disease process initially involves the adherence and colonization of the mucosal surface of the small intestine, followed by the elaboration of a heat-labile enterotoxin (LT) and/or heat-stable enterotoxin (ST). Intestinal adherence or colonization by ETEC is generally mediated by a specific surface-associated pilus (fimbrial) antigen that endows the bacteria with the capacity to adhere to epitherial cell surface. Fourteen monoclonal antibodies (MAbs) directed against pili antigens of ETEC were obtained by cell fusion/hybridoma technique. They were characterized by indirect immunofluorescence assay (IFA), and divided into four groups: specific to K99 antigen (group 1), cross-reactive with K99 and F41 antigens (group 2), specific to K88 antigen (group 3) and specific to 987P and K88 antigens (group 4), respectively. These MAbs demonstrated the distinct pili (K) antigens on the surface of ETEC by IFA, and could be utilized as diagnostic reagent for the identification of ETEC. When eighty-seven field isolates of E. coli from piglet with diarrhea were tested by group 3 MAb, fourty-two strains (48.3%) has K88 pilus antigen suggesting that this is one of the major pilus antigen of ETEC present in fifeld.

• 한국미생물학회:학술대회논문집
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• 한국미생물학회 2000년도 추계학술발표대회
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• pp.128-135
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• 2000

The thiosulfate reductase gene (PhsABC) from Salmonella typhimurium was expressed in Escherichia coli in order to produce sulfide from inorganic thiosulfate and precipitate metals as metal sulfide complexes. A 5.1-kb DNA fragment containing the native phsABC and a 3.7-kb DNA fragment, excluding putative promoter and regulatory regions were inserted into expression vectors pTrc99A and pJB866, respectively. Upon expression of phsABC, E. coli DH5$\alpha$ harboring the phsABC constructs showed higher thiosulfate reductase activity and produced significantly more sulfide than the control strain (E. coli DH5$\alpha$) under both aerobic and anaerobic conditions. Among the four constructs, E. coli DH5$\alpha$ harboring pSB74 produced the highest level of thiosulfate reductase and removed most of heavy metals from solution under anaerobic conditions. In a mixture of 100 $\mu$M each of cadmium, lead, and zinc, the strain could remove $99\%$ of the total metals from solution within 10 hours. Cadmium was removed first, lead second, and zinc last. In contrast, a negative control did not produce any measurable sulfide and removed very little metals from solution. These results have important implications for removal of metals from wastewater contaminated with several metals.

• KSBB Journal
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• 제23권5호
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• pp.369-374
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• 2008

Rhdotorula glutinis epoxide hydrolase 유전자를 pColdI 벡터 와 pET-21b(+) 벡터에 재조합하여 제작한 E. coli를 생촉매로 사용하여 라세믹 styrene oxide에 대하여 회분식 가수분해 반응을 실시하였다. pET-21b(+)/RgEH 재조합 플라스미드 DNA를 가진 E. coli를 $15^{\circ}C$에서 저온 배양할 때 수용성 단백질 형태로 가장 많이 발현되었고, 입체선택적 가수분해 활성과 촉매 안정성이 가장 좋았다. 라세믹 styrene oxide 20 mM에 대하여 반응온도 $30^{\circ}C$에서는 반응시간 20분 동안에 수율 24.0%로 (S)-styrene oxide를 얻은 반면에, 반응온도를 $10^{\circ}C$로 낮추고 0.5% (w/v) Tween 20을 첨가하고 반응시키면 광학순도 99.0% ee 이상의 (S)-styrene oxide을 46.0%의 수율로 얻을 수 있었다. 최적조건에서 E 값은 6.68이었으며, 100 mM의 라세믹 styrene oxide에 대해서는 반응시간 50분에 이론 수율 50% 대비 40%의 높은 수율로 (S)-styrene oxide를 얻을 수 있었다.

• Journal of Electrical Engineering and Technology
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• 제6권2호
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• pp.275-279
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• 2011

Sterilization of Escherichia coli (E. coli) is examined using a unique pulsed ultra-violet (UV) elliptical reactor based on Nd:YAG laser resonator, UV radiation from a pulsed xenon flashlamp. The light from the discharge has a broadband emission spectrum extending from the UV to the infrared region with a rich UV contained. Sterilization method by using the UV light is fast, environment-friendly and it does not cause secondary pollution. A Nd:YAG laser resonator having elliptical shape has advantage of concentrating the radiation of the UV light at two foci as the quart sleeve filled with E. coli. The primary objective of this research is to determine the important parameters such as pulse per second (pps), the applied voltage for sterilizing E. coli by using an UV elliptical reactor. From the experiment result, the sterilization effect of UV elliptical reactor is better than that of UV cylindrical reactor, and it can be 99.9% of sterilization at 800V regardless of the pps within 10 minutes.

• 한국미생물·생명공학회지
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• 제31권2호
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• pp.140-144
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• 2003

신호펩디드 가수분해는 모든 생물에 필수적인 단백질로 N-말단에 신호서열을 가진 단백질들의 신호서열을 잘라내는 효소로 serine과 lysine을 활성부위로 하는 특이한 dyad serine 효소류로 알려져있다. 최근에 신호펩디드 가수분해효소의 특성으로 새로운 항생제 이용 가능성 때문에 그 활성 메카니즘의 연구가 중요시되고 있다. 본 연구는 E. coli 신호펩디드 효소가 serine/lysine/aspartic acid로 하는 전형적인 triad serine 효소류의 메카니즘을 갖는다는 가정하에 Type Ⅰ 신호펩디드류의 하나인 E. coli에서 aspartic acid 99을 alanine으로 치환하여 효소의 enzymatic activity를 조사하였다. 그 결과 D99잔기는 E. coli Type Ⅰ 신호펩디드 효소의 활성메카니즘에 직접적으로 관여한다기보다는 그 효소를 구조적으로 안정화하는데 중요한 역할을 할 가능성이 있는 것으로 암시되어진다.