• Journal of Microbiology and Biotechnology
• /
• 제24권12호
• /
• pp.1685-1689
• /
• 2014

Baeyer-Villiger (BV) oxidation of cyclohexanone to ${\varepsilon}$-caprolactone in a microbial system expressing cyclohexanone monooxygenase (CHMO) can be influenced by not only the efficient regeneration of NADPH but also a sufficient supply of oxygen. In this study, the bacterial hemoglobin gene from Vitreoscilla stercoraria (vhb) was introduced into the recombinant Escherichia coli expressing CHMO to investigate the effects of an oxygen-carrying protein on microbial BV oxidation of cyclohexanone. Coexpression of Vhb allowed the recombinant E. coli strain to produce a maximum ${\varepsilon}$-caprolactone concentration of 15.7 g/l in a fed-batch BV oxidation of cyclohexanone, which corresponded to a 43% improvement compared with the control strain expressing CHMO only under the same conditions.

• 대한임상검사과학회지
• /
• 제44권3호
• /
• pp.112-117
• /
• 2012

Escherichia coli biofilm, reported to be produced in the human intestine causing a significant health risk, was successfully grown on transwell$^{(R)}$. This biofilm layer was identified by crystal violet staining and prepared for the in vitro E. coli biofilm system which can be used to screen for inhibitors. The biofilm formation did not show a change in transepithelial electrical resistance values. Furthermore, rhodamine 123 staining showed that the dye did not pass through the membrane once biofilm was formed.

• Journal of Microbiology and Biotechnology
• /
• 제14권1호
• /
• pp.1-14
• /
• 2004

More than twenty years have passed since the approval of the first recombinant DNA product for therapeutic use (recombinant human insulin, 1982). However, the biotechnology industry is still facing a shortage of manufacturing capacity due to the increasing demand of therapeutic proteins. This demand has prompted the search for a growing number of biological production systems but, nevertheless, the Gram-negative bacterium Escherichia coli remains one of the most attractive production hosts. This review highlights the most important features and developments of plasmid vector design, emphasizing the different reported strategies for improving the expression and secretion of heterologous proteins using the cellular machinery of E. coli.

• 미생물학회지
• /
• 제29권3호
• /
• pp.199-202
• /
• 1991

The O serotypes of uropathogenic Escherichia coli isolated in Korea were studied using a complete set of rabbit O antisera raised with reference O antigen type strains of E. coli. The distribution of "O" serotypes found in this survey was grossly similar with the prevalence of "O" types observed in other parts of the world, and some differences were also noted. A total of 31 "O" serotypes were identified and the most frequent serotype associated with urinary tract infections was O75(11.5%), which was followed by O6(7.4%), O10 and O40(5.7%, respectively).0 and O40(5.7%, respectively).

• 한국식품위생안전성학회지
• /
• 제7권4호
• /
• pp.157-160
• /
• 1992

쑥으로부터 추출한 정유를 Escherichia coli, Bacillus subtilis , Pleurotus ostreatus , Fusarium solani , Aspergillus nidulans에 첨가한 후 배양한 결과 다음과 같은 결과를 얻었다. 쑥의 정유를 첨가한 후 미생물을 배양시킨 결과 Escherichia coli,는 무반응이었으나 Bacillus subtilis , Pleurotus ostreatus , Fusarium solani , Aspergillus nidulans는 생육이 저해되었다. bacillus subtilis는 대조군에 비해 정유의 농도가 10~100ppm에서 10배의 생육저해를 나타냈다. 쑥의 정유는 또한 곰팡이에서 강한 생육저해를 나타냈으며 Pleurotus ostreatus는 1,000ppm의 농도에서 생육이 완전히 정지되었다.

• Journal of Microbiology and Biotechnology
• /
• 제24권11호
• /
• pp.1536-1541
• /
• 2014

Pinocembrin is a flavonoid that exhibits diverse biological properties. Although the major source of pinocembrin is propolis, it can be synthesized biologically using microorganisms such as Escherichia coli, which has been used to synthesize diverse natural compounds. Pinocembrin is synthesized from phenylalanine by the action of three enzymes; phenylalanine ammonia lyase (PAL), 4-coumarate:CoA ligase (4CL), and chalcone synthase (CHS). In order to synthesize pinocembrin from glucose in Escherichia coli, the PAL, 4CL, and CHS genes from three different plants were introduced into an E. coli strain. Next, we tested the different constructs containing 4CL and CHS. In addition, the malonyl-CoA level was increased by overexpressing acetyl-CoA carboxylase. Through these strategies, a high production yield (97 mg/l) of pinocembrin was achieved.

• 농업과학연구
• /
• 제41권3호
• /
• pp.245-249
• /
• 2014

Among dozens of DNA polymerases cloned from thermophilic bacteria, Taq DNA polymerase from Thermus aquaticus has been most frequently used in polymerase chain reaction (PCR) that is being applied to gene cloning, DNA sequencing, gene expression analysis, and detection of infectious and genetic diseases. Since native Taq DNA polymerase is expressed at low level in T. aquaticus, recombinant Escherichia coli system was used to produce Taq DNA polymerase in a large amount. Taq DNA polymerase was expressed as a soluble form under the control of tac promoter in E. coli, and purified by heat treatment and ion exchange chromatographies. The purified Taq DNA polymerase was nearly homogeneous and exhibited a similar DNA amplification activity with a commercial Taq DNA polymerase.

• 미생물학회지
• /
• 제25권3호
• /
• pp.184-188
• /
• 1987

Evidences that the mannose permease of Escherichia coli mediates the infection of N4 in early steps, were obtained as follows. First, A mutant strain of Escherichia coli which was resistant to both wild type N4 and lambda whose genome is Charon 4A containing human genomic fragments in its EcoR I site, could not use mannose efficiently. Second, N4 could not infect pel mutant strains which lack one or all of intact components of mannose permease. However, unknown alterations in N4 made it possible for the phage to infect pel mutant of E. coli. It also turned out to be clear that the receptor of N4 was different from that of lambda.

• 미생물학회지
• /
• 제53권2호
• /
• pp.118-122
• /
• 2017

납, 아연, 카드뮴에 의한 미생물 생장 저해를 변형된 Tris minimal medium을 사용하여 측정하였다. Escherichia coli 균주에 대한 독성의 세기는 아연 > 카드뮴 > 납 순으로 나타났고 Streptomyces coelicolor A3(2)의 철 함유 superoxide dismutase 2를 과발현하는 E. coli 균주는 중금속 저항성이 증가되었음을 알 수 있었다.

• Food Science and Biotechnology
• /
• 제17권6호
• /
• pp.1365-1367
• /
• 2008

The antibacterial activity of chitosan against Escherichia coli was investigated in the presence of NaCl, sucrose, and ethanol to assess the potential use of chitosan as a biopreservative in food products containing these components. The inhibitory activity of chitosan decreased slightly upon the addition of NaCl and sucrose, respectively to culture broth containing 100 ppm of chitosan (Mw 3,000), while the addition of ethanol enhanced the inhibitory activity of chitosan on growing cells. The addition of these components to non-growing cells prior to chitosan treatment demonstrated that NaCl protected the cells from the inhibitory activity of chitosan, while sucrose had no effect. Ethanol addition to non-growing cells increased cell death by chitosan treatment. Finally, binding of fluorescein isothiocyanate (FITC)-labeled chitosan to E. coli was measured in the presence of the food components. The FITC-labeled chitosan binding to cells decreased upon NaCl addition, was not affected by sucrose, and increased following treatment with ethanol.