• Journal of Microbiology
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• v.44 no.6
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• pp.671-673
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• 2006

A new 4.87 kb Escherichia-Pseudomonas shuttle vector has been constructed by inserting a 1.27 kb DNA fragment with a replication origin of a Pseudomonas plasmid pRO1614 into the 3.6 kb E. coli plasmid pBGS18. This vector, designated pJH1, contains an aminogly-coside phosphotransferase gene (aph) from Tn903, a lacZ' gene for $\alpha$-complementation and a versatile multiple cloning site possessing unique restriction sites for EcoRI, SacI, KpnI, SmaI, BamHI, XbaI, SalI, BspMI, PstI, SphI, and HindIII. When pJH1 was transformed into E. coli DHS${\alpha}$ and into P. putida HK-6, it was episomally and stably maintained in both strains. In addition, the enhanced green fluorescent protein (EGFP) gene which was transcriptionally cloned into pJH1 rendered E. coli cells fluorescence when its transformants were illuminated at 488 nm.

• Korean Journal of Microbiology
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• v.31 no.1
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• pp.27-36
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• 1993

Rhizobium fredii USDA191 은 대기 중의 질소를 환원하여 식물체의 생육에 필요한 질소원을 공급해주는 세균으로 다량의 체외 다당류를 합성한다. 전위요소 Tn5의 삽입에 의한 돌연변이 유도로 다당류결핍 변이주 R. fredii YKL293 가 분리되었으며 이 변이주로부터 Tn5 에 인접한 DNA 단편이 pUC19 에 클로닝되었고(plyk5293),이 DNA 단편을 탐침으로 하여 .lambda.NM1149 에 구성되 USDA191 genomic library 로부터 야생형체외다당류 합성관련 유전자(exo) 를 함유한 클론 .lambda. NM1149 22E 를 plaque 혼성화에 의하여 분리하였다. 클론 NM1149.22E 에 들어있는 exo 유전자를 pBR322 에 옮겨서 pJW33을 만들고, 재조합체 pJW33 을 Escherichia coli POII734 에 도입시켜 lacZ 구조유전자를 함유한 MudI 1734 가 exo 유전자의 프러모토와 융합되어 lacZ 구조유전자의 전사가 이루어지도록 하였다. 위와 같이 만들어진 재조합체 플라스미드 pUM21을 함유한 E. coli JM83 은 .betha.-galactosidase 를 합성하였으며, 야생형 tacZ 유전자를 갖고 있는 E. coli LE392 에 비해서 14-25배 정도 낮은 역가를 보였다.

• Journal of Aquaculture
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• v.7 no.1
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• pp.41-54
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• 1994

In order to evaluate the availability of lacZ as a reporter gene for producing transgenic mud loach, foreign DNA, bacterial \beta-galactosidase$ gene (lacZ) was microinjected into mud loach eggs and its insertion and expression were examined. X-gal based histochemical assay, fluorimetric analysis of \beta-galactosidase$ with 4-methylumbelliferyl-$\beta$-D-galactoside (MUG) and molecular biological examination using polymerase chain reaction (PCR), dot blot, southern blot and sequence analysis of PCR products were carried out to analyze both microinjected group and non-injected controls. The results are disccussed in this paper.

• Microbiology and Biotechnology Letters
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• v.23 no.3
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• pp.288-296
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• 1995

To investigate high-level expression of Serratia marcescens metalloprotease (SMP) in Escherichia coli and S. marcescens, we constructed various recombinant plasmids: pSP2, containing SMP gene and lac promoter; pKSP2, containing SMP gene and tac promoter; pTSP2, containing SMP gene, trc99a promoter, and lacI$^{q}$. The recombinant E. coli (pKSP2) strain expressed SMP to a high-level, about 36% of total cellular proteins but accumulated inactive SMP precursors intracellularly, which indicated that E. coli does not have activation and secretion system for SMP. To overproduce active SMP, we transformed S. marcescens with the recombinant plasmids by a modified CaCl$_{2}$ method. The recombinant S. marcescens ATCC27117 (pSP2) containing lac promoter for SMP transcription produced 530 U/ml of active SMP on LB broth, which is about 5.1 times of the SMP yield, 105 U/ml of a control strain, S. marcescens ATCC27117 (pUC19). However, S. marcescens ATCC27117 (pKSP2) containing tac promoter for SMP transcription did not grow healthy and hardly produced SMP. To overcome a harmful effect of the strong tac promoter, we constructed a regulatory plasmid pTSP2 containing a strong trc99a promoter and its repressor gene lacI$^{q}$. When S. marcescens ATCC27117 (pTSP2) was induced with 1.0 mM IPTG after 9 hr cultivation, 2,200 U/ml of SMP was obtained in LB broth, which is about 21 times of that of a control strain.

• Journal of the Korean Society of Radiology
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• v.8 no.1
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• pp.35-42
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• 2014

The purpose of this study is to know the differences of metabolism in abnormal brain disease using a single-voxel proton MR spectroscopy(1H MRS) Together with five normal volunteers and each five patients with brain diseases, pathologically proved, underwent MRI and 1H MRS. The quantitative results of 1H MRS in adrenoleukodystrophy(ALD), hepatic encephalopathy(HE), and infarction gave unique information on the metabolite changes related with the white matter: the concentration of NAA decreased in all diseases; Cho, mI and Lac increased in ALD; Cho decreased in HE; and ${\beta}{\cdot}{\gamma}$-Glx and Lac increased in infarction. It is concluded that 1H MRS is capable of diagnosing brain diseases by monitoring metabolite changes in vivo that subsequently develope into abnormalities. 1H MRS may be a useful clinical tool for in both diagnosis and prognosis of brain diseases.

• Proceedings of the Korean Society of Toxicology Conference
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• 2001.10a
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• pp.181-181
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• 2001

1,2-Dibromo-3-chloropropane (DBCP), a soil fumigant against nematodes, is a genotoxic carcinogen and also is classified by World Wildlife Fund as endocrine disruptors. DBCP has been extensively studied on genotoxicity, carcinogenicity, and damage in male reproductive-related organs. However, information on precise mechanism of mutagenesis and carcinogenesis of DBCP is yet unknown. Thus the mutation spectrum and mechanism of DBCP was determined in lacI transgenic Big Blu $e^{R}$ Rat2 fibroblast cell lines.(omitted)d)

• Korean Journal of Weed Science
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• v.15 no.3
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• pp.206-213
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• 1995

Glyphosate(N-[phosphonomethyl]glycine) applied to the assimilate-exporting leaves(i.e. third old leaf) of tomato(Lycopersicon esculentum Mil var. Moneymaker). Herbicide binding protein, QB protein(D1), has been immunoblotted using the antibodies raised against the hybrid-protein expressed by a part of spinach psb A gene cloned in frame with the 3'end of lac Z gene to allow expression of the ${\beta}$-galactosidase(EC 3.21.23) in Escherichia coli. Glyphosate has an effect on a turnover of D1 within photosystem II of thylakoid membrane. The dysfunction of D1 protein within light harvesting complex(LHC-II) seems to be a pleiotropic effect of glyphosate.

• Microbiology and Biotechnology Letters
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• v.19 no.1
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• pp.45-51
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• 1991

Inserting the $cI_{857}$ structural gene in the downstream of the tac promoter for the overproduction of $cI_{857}$ repressor protein was studied. DNA fragment containing $cI_{857}$ ; repressor gene was amplified by using plasmid pUC12, and partially digested with HphI. Only the $cI_{857}$ structural gene isolated was inserted in the downstream of the tac promoter. Plasmid pDR540- $cI_{857}$ having the tuc promoter-$cI_{857}$ structural gene insert could be isolated by the immunity of cells resistant at $30^{\circ}C$ and cell lysis at $42^{\circ}C$ to $\lambda$ phage $cI_{90}$. The amount of $cI_{857}$ repressor as 17% of total cellular protein were produced by using general E. coli as well as $lacI^q$ JM103 having this plasmid.

• Journal of Life Science
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• v.15 no.4 s.71
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• pp.553-560
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• 2005

The stf (Salmonella typhimurium fimbriae) operon consisting of stfA(CDEFG assumes to encode putative fimbriae. The complete stf operon is existed in S. typhimurium and S. choleraesuis, whereas it is absent in S. typhi. Analyses of the amino acid residues between major subunit StfA of the Stf fimbriae and those of known other fimbriaes suggested that Stf belongs to class I type fimbriae. Through comparison of StfD chaperone with the other fimbrial chaperones, and of C-terminus in subunits of Stf fimbriae, it belongs to FGS (with a short Fl-G1 loop) subfamily. In order to investigate the expression of stf operon, we have constructed a Salmonella strain containing a chromosomal stfA::lacZYA transcriptional fusion, resulting in S. typhimurium $_X8532$. The strain $_X8532$ lacked the expression of \beta-galactosidase$ under normal culture conditions. However, with longer incubation time of the S. typhimurium $_X8532$, we have isolated 21 individual strains exhibiting $Lac^+$ phenotype. $Lac^+$ phenotype was appeared as approximately 0.03 frequency per generation. All isolates expressed lacZ constitutively in the various environmental conditions. Various global regulatory proteins including RpoS, OmpR, and CpxR were not involved in the regulation of the stf operon. A S. typhimurium $_X8661$ mutant lacking stfAC function attenuated 6.7 folds more than that of wild type $_X3761$ in the mouse virulence test, suggesting in the somehow involved in the Salmonella pathogenesis.

• Journal of Microbiology and Biotechnology
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• v.26 no.1
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• pp.139-144
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• 2016

Synthetic oscillators are gene circuits in which the protein expression will change over time. The delay of transcription, translation, and protein folding is used to form this kind of behavior. Here, we tried to design a synthetic oscillator by a negative feedback combined with a positive feedback. With the mutant promoter P_LacC repressed by LacIq and P_Lux activated by AHL-bound LuxR, two gene circuits, Os-LAA and Os-ASV, were constructed and introduced into LacI-deleted E. coli DH5α cells. When glucose was used as the carbon source, a low level of fluorescence was detected in the culture, and the bacteria with Os-ASV showed no oscillation, whereas a small portion of those carrying Os-LAA demonstrated oscillation behavior with a period of about 68.3 ± 20 min. When glycerol was used as the carbon source, bacteria with Os-ASV demonstrated high fluorescence value and oscillation behavior with the period of about 121 ± 21 min.