• 미생물학회지
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• 제43권2호
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• pp.116-123
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• 2007

본 연구는 부산지역 하천에서 plasmid 매개성 광범위 ${\beta}-lactam$ 분해효소(extended spectrum ${\beta}-lactamase;\;ESBL$)를 생성하는 세균을 분리하여 생성된 광범위 ${\beta}-lactam$ 분해효소를 유형별로 분류하기 위함이다. Escherichia coli 6균주와 Klebsiella pneumoniae 15균주가 피전달균주인 Escherichia coli J53 $Azid^{R}$에 plasmid 매개성 광범위 ${\beta}-lactam$ 분해효소 생성 인자를 전달하였다. PCR 후 얻은 유전인자를 plasmid로 매개된 광범위 ${\beta}-lactam$ 분해효소 유전자의 염기서열 분석결과, E. coli와 K. pneumoniae 유전자를 BCM Search Launcher 및 GenBank nucleotide database를 통하여 검색한 결과 ESBL 유형은 TEM-52형과 SHV-12형이었다. TEM-52는 E. coli와 K. pneumoniae 양쪽에서 분리되었다. 그러나 SHV-12는 K. pneumoniae에서만 분리되었다. 이상의 결과로부터 plasmid 매개성 광범위 ${\beta}-lactam$ 분해효소를 생성하는 세균이 한국에서는 이미 임상범위를 넘어 자연계까지 확산되었음을 알 수 있었다.

• 방사선산업학회지
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• 제5권1호
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• pp.63-67
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• 2011

A comparative experiment was conducted to compare the effects of persulfate with gamma radiation on the disinfection efficiencies against Escherichia coli K12. The microorganism used for the disinfection experiments were prepared by transferring a bacterial stock culture into a 50 ml nutrient broth an incubating for 24 hrs at $37^{\circ}C$. The initial concentration of the harvested culture was approximately $10^7$ to $10^9CFU\;ml^{-1}$. The culture solution was irradiated at different absorbed doses of 0.1, 0.2, 0.3, 0.4, 0.5, 0.7, and 1 kGy, respectively. The disinfection efficiency of persulfate with gamma radiation of 0.3 kGy against Escherichia coli K12 was 97.2% and while the gamma radiation only was 90.01% at 0.3 kGy. Therefore, it could be thought that addition of persulfate in the disinfection of Escherichia coli K12 can enhance the disinfection efficiency when it is used together with gamma radiation.

• 생명과학회지
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• 제20권5호
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• pp.676-682
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• 2010

본 연구는 임상검체만이 아닌 주변 생활환경에도 광범위 베타 락탐분해효소를 생성하는 균주(extended-spectrum $\beta$-lactamase, ESBL)가 존재하는지를 확인하고 만약 존재할 경우 그 균주를 분리하고 ESBL유형을 알아보기 위하여 실시되었다. 부산 광안리 하수처리 방류수에서 이중 디스크 확산 검사 결과 양성반응을 나타낸 29균주를 선별하였다. 이중 sodium azide에 내성을 가진 피전달 균주인 Escherichia coli J5에 교차접합이 이루어진 15균주를 대상으로 indole, methyl-red, Voges-Proskauer, Simmon's citrate 시험과 decarboxylase-dihydrolase 및 여러 종류의 당 발효 시험 등 생화학 검사를 실시한 결과 Klebsiella pneumoniae(13균주)와 Escherichia coli(2균주)가 동정되었다. 등전점, PCR, 유전자서열 분석을 실시하여 ESBL 유형을 결정하였다. Klebsiella pneumoniae의 ESBL 생성유형은 SHV-12(4균주)와 SHV-12/TEM-1(9균주)의 2종류로 구분되었고, Escherichia coli의 ESBL 생성유형은 TEM-1(2균주)로 판명되었다.

• 한국식품영양학회지
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• 제19권4호
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• pp.526-531
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• 2006

자몽 종자 추출물의 항균성을 조사하기 위하여 그람 양성균인 Bacillus cereus, Bacillus subtilis, Listeria monocytogenes와 그람 음성균인 Escherichia coli, Salmonella enteritidis, Serratia marcescem를 대상으로 하여 최소 저해 농도, 생육 저해 활성, 콜로니 형성 저해 활성을 실험하였다. 그람 양성균에 대한 자몽 종자 추출물의 최소 저해 농도는 12.5 ppm정도로 상대적으로 낮았으며, 그람음성균의 최소저해 농도는 50ppm 이상으로 상대적으로 높았다. 균주의 증식에 대한 생육 저해 활성을 조사한 결과 Bacillus cereus는 1ppm 이하, Bacillus subtilis는 6.25 ppm, Listeria monocytogenes는 1ppm 이하, Escherichia coli는 6.25 ppm, Salmonella enteritidis는 25 ppm Serratia marcescem는 25pp부터 생육이 저해되었다. 그람 양성균의 콜로니 형성 저해활성은 Bacillus cereus는 93.9%, Bacillus subtilis는 94.0%, Listeria monocytogenes는 99.9%, 그람 음성균의 콜로니 형성 저해 활성은 Escherichia coli는 4.4%, Salmonella enteritidis는 82.7%, Serratia marcesem는 86.4%로, 그람 양성균에 대해서는 높은 저해 활성을 보였으며, 그람 음성균에 대해서는 비교적 낮은 저해 활성을 보였다.

• Biomolecules & Therapeutics
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• 제12권3호
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• pp.179-184
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• 2004

The FimH subunit of type 1-fimbriated Escherichia coli has been determined as a major cause for urinary tract infections. In our previous study, the Adhesin/CTXA2B was expressed as soluble recombinant chimaeric protein derived from the uropathogenic Escherichia coli adhesin genetically coupled to cholera toxin A2B (CTXA2B) subunit in Escherichia coli. Since it is very important to optimize IPTG concentration and culture temperature to maximize cell growth and productivity, These optimal culture factors were determined to increase the productivity of the expressed Adhesin/CTXA2B chimaeric protein in Escherichia coli TB1 carrying pMALfimH/ctxa2b. Our data demonstrate that optimal concentration of IPTG for increased production of chimaeric protein was 0.5 mM. Additionally, culture time was 10 hours and temperature, 37${\circ}C$.

• Journal of Microbiology and Biotechnology
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• 제27권11호
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• pp.2028-2036
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• 2017

The Escherichia coli K-12 and B strains are among the most frequently used bacterial hosts for scientific research and biotechnological applications. However, omics analyses have revealed that E. coli K-12 and B exhibit notably different genotypic and phenotypic attributes, even though they were derived from the same ancestor. In a previous study, we identified a limited number of proteins from the two strains using two-dimensional gel electrophoresis and tandem mass spectrometry (MS/MS). In this study, an in-depth analysis of the physiological behavior of the E. coli K-12 and B strains at the proteomic level was performed using six-plex isobaric tandem mass tag-based quantitative MS. Additionally, the best lysis buffer for increasing the efficiency of protein extraction was selected from three tested buffers prior to the quantitative proteomic analysis. This study identifies the largest number of proteins in the two E. coli strains reported to date and is the first to show the dynamics of these proteins. Notable differences in proteins associated with key cellular properties, including some metabolic pathways, the biosynthesis and degradation of amino acids, membrane integrity, cellular tolerance, and motility, were found between the two representative strains. Compared with previous studies, these proteomic results provide a more holistic view of the overall state of E. coli cells based on a single proteomic study and reveal significant insights into why the two strains show distinct phenotypes. Additionally, the resulting data provide in-depth information that will help fine-tune processes in the future.

• 미생물학회지
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• 제45권2호
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• pp.163-169
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• 2009

본 논문은 부산소재 하수처리장 중계시설인 민락오수처리장의 하수에서 광범위 베타 락탐 분해효소(extendedspectrum $\beta$-lactamase, ESBL) 생성균주를 분리 동정하고 이들이 생성한 ESBL 유형을 조사하였다. 민락오수처리장은 부산 남구 수영구의 민락동 일대에 밀집한 횟집의 하수를 모아서 남구 용호동에 있는 하수종말처리장으로 중계시키는 시설이다. 2009 년 1 월 하수 검체로부터 항균제 이중 디스크 확산 시험(double disk synergy test)에 양성반응을 나타낸 19 균주를 1차 시험균주로 선택하였다. 인돌생성 시험 methyl-red, Voges-Proskauer, Simmon's citrate, decarboxylase-dihydrolase 및 당 발효능 생화학 시험을 통하여 Klebsiella pneumoniae (3 균주)와 Escherichia coli (16 균주)가 동정되었다. 이 균들을 공여균주로, Escherichia coli J53 (sodium $azide^r$)를 피전달균주로 하여 접합시험을 실시하여 plasmid로 매개된 4 균주 접합체를 얻었다. 이들로부터 plasmid를 추출하여 PCR로 유전자 증폭을 시켜 유전자를 분석하고 등전점을 조사한 결과 Klebsiella pneumoniae에서 생성된 ESBL 유형은 모두 SHV-12 (3 균주)였고, Escherichia coli에서 생성된 ESBL 유형은 SHV-12/TEM-1 (1 균주)였다.

• 대한의생명과학회지
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• 제17권1호
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• pp.7-12
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• 2011

Free-living amoebae ingest several kinds of bacteria. In other words, the bacteria can survive within free-living amoeba. To determine how Escherichia coli K1 isolate causing neonatal encephalitis and non-pathogenic K12 interact with free-living amoebae, e.g., Acanthamoeba castellanii (T1), A. astronyxis (T7), Naegleria fowleri, association, invasion and survival assays were performed. To understand pathogenicity of free-living amoebae, in vitro cytotoxicity assay were performed using murine macrophages. T1 destroyed macrophages about 64% but T7 did very few target cells. On the other hand, N. fowleri which needed other growth conditions rather than Acanthamoeba destroyed more than T1 as shown by lactate dehydrogenase (LDH) release assay. In association assays for E. coli binding to amoebae, the T7 exhibited significantly higher association with E. coli, compared with the T1 isolates (P<0.01). Interestingly, N. fowleri exhibited similar percentages of association as T1. Once E. coli bacteria attach or associate with free-living amoeba, they can penetrate into the amoebae. In invasion assays, the K1 (0.67%) within T1 was observed compared with K12 (0%). E. coli K1 and K12 exhibited high association with N. fowleri and bacterial CFU. To determine the fate of E. coli in long-term survival within free-living amoebae, intracellular survival assays were performed by incubating E. coli with free-living amoebae in PBS for 24 h. Intracellular E. coli K1 within T1 (2.5%) and T7 (1.8%) were recovered and grown, while K12 were not found. N. fowleri was not invaded and here it was not recovered.

• 미생물학회지
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• 제26권2호
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• pp.113-121
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• 1988

Ozone, an atmospheric pollutant, can damage similar UV and X-rays DNA and its components. It is possible then that the KNA damage produced by this gas are similar, to some extent, to those of radiations and that they could be repaired by the same DNA repair mechanisms. It has been observed in Escherichia coli that radiosensitive strains such as lex A, rec A and pol A, all deficient to some extent for DNA repair, are more sensitive to ozone than a wild type strain. We have thendetermined the ozone resistance and host-cell reactivation of ozone-damaged T3 phages for the E. coli double mutants pol A, lex A, uvr B, lex A, uvr A, rec A and rec A lox A. According to the results, the DNA polymerase 1 plays a key role in ozone resistance and Type 11 mechanism and/or shory patch excision repair are the most important for it. The interactions between the different DNA repair mechanisms are secondary. There is a strong correlation between ozone resistance and the capacity to reactivate T3 phages damaged by ozone.

• 한국식품영양학회지
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• 제6권3호
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• pp.169-177
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• 1993

The conversion of glutamate by glutamine synthetase Is the endergonic reaction that demands ATP as its energy source. In order to supply efficiently ATP that is demanded in the conversion of glutamate to glutamine, the ATP- generating system by acetate kinase partially purified from Escherichia coli K-12 was coupled with glutamine synthetase partially purified 5. coli K-12 Pgln6. The optinum conditions of the coupled reaction were investigated. As the result, the highest conversion of glutamate to glutamine was shown In the reaction mixture containing 100mM glutamate, 100mM NHtCl, 50M acetyl phosphate, 5mM ADP, 40M MgCl2, 300mM potassium phosphate buffer (pH 7.5), 5mM MnCl2, Under this condition, the most effective concentrations of enzyme were 70unit/ml glutamine synthetase and 99unit/ml acetate kinase. Under the optinum conditions, 98% of 100mM glutamate was converted to glutamine within 6 hours.