• 한국식품영양과학회지
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• 제27권6호
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• pp.1173-1176
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• 1998

Glycogen synthetase[EC 2.4.1.21] in E. coli B was isolated and purified by sonication, ultracentri fugation, DEAE cellulose chromatography and gel chromatography. In the case of using glycogen or maltotriose as a primer in the enzyme reaction, 64% and 23.7% of labelled ADP glucose were incorporated into primer, respectively. 8.1% of labelled ADP glucose was polymerized into glycogen in enzymatic reaction without a primer.

• Journal of Microbiology
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• 제40권2호
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• pp.98-103
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• 2002

Twenty-eight clinical isolates of Escherichia coil, composed of thirteen norfloxacin resistant isolates (MIC of >16${\mu}$g/ml), one intermediately resistant isolate (MIC of 8${\mu}$g/ml), and fourteen susceptible isolates (MIC of <4${\mu}$g/ml), were randomly selected to study the norfloxacin resistance mechanism and phylogeny in clinical isolates in Korea. Eleven nofloxacin resistant isolates and one susceptible isolate were multi-drug resistant (MDR). Every norfloxacin resistant isolate with MIC higher than 32${\mu}$g/ml had the same three mutations: Ser83\longrightarrowLeu and Asp87\longrightarrowAsn or Tyr in GyrA and Ser80\longrightarrowIle in ParC. Whereas a resistant isolate with MIC of 16${\mu}$g/ml had three mutations but Asp87 in GyrA was replaced with Gly instead of Asn. The intermediately resistant isolate had the same two mutations in GyrA but a different mutation in ParC, Glu84\longrightarrowLys. Among the susceptible isolates, two isolates with MIC of 4${\mu}$g/ml had one mutation: Ser83\longrightarrowiLeu in GyrA, and no mutation was found in the susceptible isolates. Resistant isolates showed higher efflux activity than the susceptible ones, with random amplification of polymorphic DNA (RAPD), six susceptible isolates form a separate group from the rest of the isolates.

• 한국동물학회지
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• 제38권4호
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• pp.565-569
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• 1995

분열형 호모인 Schizosaccbarornyces pombe에서 RecA 유사 단백질은 hydroxyurea (HU)나 methotrexate (MTX)와 같은 nucleotide pool 형성에 관여하는 효소의 저해제에 의해 유도발현된다. 본 연구에서는 대장균의 RecA 단백질과 S. pombe의 ribonucleotide reductase가 구조적으로 유사한지를 RecA 항체를 이용한 면역침전법과 [5-$^3$H]CDP를 기질로하는 thin layerchromatography방법을 통하여 알아보고자 하였다. S. pombe의 rinonucleotide reductase활성은 100mM HU에 의해 대조군에 비해 26.3% 저해되었으며, RecA 항체를 이용한 면역침전에 의해서도 43.3% 저해되었다. 이와 같은 결과는 S. pombe의 rinonucleotide reductase가 대장균의 RecA 단백질과 구조적으로 유사함을 시사하는 것이다.

• 한국동물위생학회지
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• 제15권2호
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• pp.134-143
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• 1992

The present study was conducted to investigate the biochemical characteristics and anti-biotic resistance of Escherichia coli(E. coli) isolated from piglets with diarrhea in Kyongbuk province during the Period from February to November 1991. 368 E. coli strains were isolated from 382 piglets with diarrhea and the biochemical and cultural reaction were compared with the classification criteria of Edwards and Ewing. Tetracycline and sulfadimethoxine were found to be highly ineffective at in vitro inhibition of the E. coli of piglets origin. The majority of E. coli were susceptible to amikacin, chloramphenicol and gentamicine. 89 (89.0%) of 100 strains of E. coil were resistant to one or more drugs. The organisms resistant to 20 or 3 drugs were 54(60.6%) of 89 strains, whereas 16(17.9%) strains were found to be resistant to one drug. 55(61.8%) out of 89 drug resistance strains carried R factors($R^+$) which were transfer-able to the recipients by conjugation.

• 한국산학기술학회논문지
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• 제9권5호
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• pp.1344-1348
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• 2008

본 연구는 고삼추출물과 황금추출물의 항균활성을 스킨케어화장품의 기본제형인 화장수, 로션에 적용, 관찰하여 식물유래의 천연항균제로써의 화장품에서의 방부시스템을 연구하였다. Test group에 고삼추출물 1%와 황금 추출물 1%, 0.5%씩의 고삼추출물과 황금추출물을 함유시켜 parabens와 imidazolidinyl urea가 함유된 positive control을 Escherichia coil, Pseudomonas aeruginosa, Staphylococcus aures, Candida albicans의 4가지 균에 대하여 실험하였다. 그 결과 고삼추출물과 황금추출물이 함유된 group은 control과 비교하여 4가지 균에 대하여 우수한 항균활성을 보였다. 고삼추출물과 황금추출물을 함께 사용하였을 때의 항균활성은 positive control과 비슷하게 나타나므로써 탁월한 항균활성을 보였다.

• Journal of Microbiology
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• 제40권2호
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• pp.91-97
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• 2002

Enteroaggregative E. coil (EAEC) is an important aethiological causal agent of diarrhea in people of developed and undeveloped countries. Different in vitro and in vivo models have been proposed to study the pathdgenic and immune mechanisms of EAEC infaction. The aim of this study was to analyze whether BALB/c mice could be used as an animal model to study EAEC pathogenesis Six-week-old BALB/c mice were inoculated with EAEC strain 042 (044:H88) nalidixic acid resistant, and re-inoc-ulated ten days after. Mice feces were monitored for the presence of the EAEC strain over a period of 20 days . Bacteria were enumerated on MacConkey agar containing 100$\mu$g of nalidixic acid per ml. Results showed that 35% of the animals were colonized for 3 days, 15% for 5 and 10% for more than 7 days . After re-inoculation only 16% of the animals remained colonized for more than 3 days. During the necropsy, the intestinal fluid of same of the infected animals presented mucus and blood. Six of these fluids showed the presence of IgA antibodies againset Pet toxin and IgG natibodies raised against the toxin were also detected in the animal serum. Histopathologic evidence confirms the stimulation of mucus hypersecretion, an increased amount of goblet cells and the presence of bacterial aggregates in the apical surfaces of intestinal epithelial cells. Edema was present in the submucosa. These results suggest that BALB/c mice could be used as an animal model for in vivo study of EAEC infection.

• 대한수의학회지
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• 제36권2호
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• pp.379-387
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• 1996

The objects of the present study were to establish the method of purification, subunit dissociation of verotoxin-2 (VT2) produced by Escherichia coli O157:H7, and to investigate the characteristics of purified verotoxin-2 such as molecular weight and composition of amino acid. The results were summerized as follows; Verotoxin-2 was extracted by addition of polymyxin B sulfate into bacterial cell lysate prepared from Escherichia coli O157:H7(KSC109). As an initial step, the bacterial cell lysate was precipitated with 30% saturated ammonium sulfate. The precipitated crude toxin was then subjected to anion-exchange, chromatofocusing and cation-exchange chromatography. Using this scheme, we obtained highly purified toxin with a specific activity of $1.1{\times}10^9$ $CD_{50}/mg$. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE) for purified VT2 showed two protein bands. The upper band, approximately 32 Kd, was supposed as A subunit and the lower band, approximately 7.7 Kd, was supposed as B subunit. When the toxin was separated in the subunit-dissociating solution, two peaks emerged with retention times of 15 and 28 min by HPLC. These peaks represented A subunit and B subunit, respectively. The amino acid composition of purified VT2 were made up in order of glutamic acid, histamine, asparaginic acid, histidine, lysine, alanine and leucine etc. The largest amount among the amino acid composing VT2 was methionine.

• 한국식품과학회지
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• 제32권1호
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• pp.218-224
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• 2000

분자량이 상이한 세 종류의 키토산의 항균활성을 E. coli O157 : H7, S. aureus 및 C. albicans 균주를 이용하여 측정, 분석하였다. E. coli O157 : H7와 S. aureus에 대해서는 분자량 10,000인 키토산이 가장 강한 항균활성을 보였으며 C. albicans에 대해서는 6량체의 키토산 올리고당이 가장 강한 활성을 나타내었다. 키토산 첨가농도는 E. coil O157 : H7와 S. aureus의 경우 0.1 mg/mL의 농도에서, C. albicans의 경우는 chitohexaose 1 mg/mL의 농도에서 항균활성이 가장 높았다. 모든 키토산 처리구에서 미생물 사멸 속도는 키토산 처리 1시간 이내에서 가장 높게 나타났으며 그 이후로는 점차 낮은 속도를 보였다. 사멸되었거나 파손된 미생물 세포로부터 유래되는 단백질, 핵산물질 및 $Ca^{2+}$ 량은 키토산 처리 시간 이내에 가장 많았으며 ${\beta}-galactosidase$ 활성도 같은 시간대에서 가장 빠른 속도로 중대되는 것으로 나타났다. S. aureus에 대한 세포막 손상 정도를 측정하여 본 결과 전체 미생물균체중 약 10%에 상당하는 균수가 막손상을 가져 왔다. 따라서, 키토산은 고유의 양이온성 성질을 이용하여 미생물의 세포벽과 세포막에 결합하여 그 결과로 세포 내 물질의 세포 외로의 유출내지는 세포막 대사의 저해 등의 효과를 나타냄으로써 항균활성을 나타내는 것으로 추측되었다.

• 대한수의학회지
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• 제26권1호
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• pp.69-77
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• 1986

The purpose of this study was the examination for presence of K99 antigen (K99), enterotoxigenicity, 0-groups, colicin and antibiotic susceptibility among E. coil isolated from calves and cows. A total of 49(18.7%) among 262 strains, isolated from 30(26.5%) out of 113 calves and cows, possesed K99, and thirty three of 49 $K99^+$ strains produced ST. Of the strains of diarrheal calf origin which less than 15 days old, a high correlation was observed between enterotoxigenic ability and K99: 92.3% of the $K99^+$ strains produced heat stable enterotoxin(ST). In O group typing of 33 $ST^+$ strains, they belonged to O20(48.4%), O8(9.1%), O9(6.1%), O139(6.1%), O149(6.1%), O101(3.0%), O115(3.0%), except six which were untypable or autoagglutinable. Of 262 E. coil isolates, 30 strains(13.3%) produced colicin and K99 were detected in 6 strains. One hundred eighty eight strains(71.8%) of 262 E. coil isolates were resistance to ampicillin, chloramphenicol, gentamicin, kanamycin, streptomycin, tetracycline, alone or in combination thereof. One hundred and fourteen(60.6%) out of 188 drug resistance strains carried R factor($R^+$) which were transferable to the recipients by conjugation. Sixty five $R^+$ strains(57.0%) carried thermo-sensitive R plasmid.

• 대한수의학회지
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• 제26권1호
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• pp.103-108
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• 1986

The oil emulsion and alhydrogel pilli vaccines were prepared from a strain(O9: K35, K99, F41) of enterotoxigenic Escherichia coli isolated from calves with diarrhea and their immunogenicity was tested in guinea-pigs, pregnant goats and cows. Serum antibody responses to K99 and F41 antigens in guinea-pigs given experimental oil and gel vaccines peaked at 4 and 6 weeks after vaccinations. At that time, the mean hemagglutination inhibition titers to K99 and F41 antigens in guinea-pigs given oil vaccine were 1:25 and 1:1, 218 and those given gel vaccine were 1:54 and 1:724 respectively. Agglutinin titers in pregnant goats given the oil vaccine were significantly higher(mean 1:2,347) compared to those of control group(mean 1:160). Less than 12.5% of goatlings from vaccinated goats developed scours compared to nearly 100% in control group after oral challenge with enterotoxigenic Escherichia coil within 24 hours after birth. The highest agglutinin titers of cow serum and colostrum and of the serum of calves 48 hours after birth from cows given oil vaccine were 1:256, 1:512 and 1:64 respectively. On the other hand, those titers of serum and colostrum and of the serum of nursing calves from nonvaccinated cows were 1:8, 1:16 and 1:20 respectively. The protective efficacy of the oil emulsion vaccine was 72.1% under field conditions. These results strongly indicated that the vaccine could be applied for protection of diarrhea caused by enterotoxigenic Escherichia coli in calves.