• Microbiology and Biotechnology Letters
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• v.14 no.2
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• pp.181-186
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• 1986

A defective lambda transducing phase carrying acetyl CoA carboxylase gene (fabE) from Escherichia coli chromosome (72 min on the current linkage map) has been isolated. A restriction map of the chromosomal region from defective transducing phage was established by digestion with combination of the restriction enzymes. No cleavage site for the enzyme EcoRI was found in this region. Restriction fragments were cloned from defective transducing phage into high copy number plasmid vector pACYC184 to generate hybrid plasmids which were capable of complementation of fabE temperature sensitive mutation. We show here that the fabE gene is located on a 3.4 megadalton Bam HI-SalI fragment with a HindIII site, which lies within the 7.4 megadalton BglIIfragment, by complementation analysis.

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.217.2-217.2
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• 2003

In the type II system. there are two elongation enzymes in E. coli, FabB is well-known to its ability to elongate cis-3-decenoly-ACP (C10:1) in unsaturated fatty acid synthesis, whereas FabF is important for the thermal regulation of fatty acid composition by its ability to elongate palmitoleic acid to vaccenic acid. based on their genetic mutation anaylsis. Radiochemical enzyme assay was performed using myristoyl-ACP as a substrate, which is known for general substrate of FabB and FabF. (omitted)

• Journal of Microbiology and Biotechnology
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• v.22 no.7
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• pp.990-999
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• 2012

The microbial biosynthesis of fatty acid of lipid metabolism, which can be used as precursors for the production of fuels of chemicals from renewable carbon sources, has attracted significant attention in recent years. The regulation of fatty acid biosynthesis pathways has been mainly studied in a model prokaryote, Escherichia coli. During the recent period, global regulation of fatty acid metabolic pathways has been demonstrated in another model prokaryote, Bacillus subtilis, as well as in Streptococcus pneumonia. The goal of this study was to increase the production of long-chain fatty acids by developing recombinant E. coli strains that were improved by an elongation cycle of fatty acid synthesis (FAS). The fabB, fabG, fabZ, and fabI genes, all homologous of E. coli, were induced to improve the enzymatic activities for the purpose of overexpressing components of the elongation cycle in the FAS pathway through metabolic engineering. The ${\beta}$-oxoacyl-ACP synthase enzyme catalyzed the addition of acyl-ACP to malonyl-ACP to generate ${\beta}$-oxoacyl-ACP. The enzyme encoded by the fabG gene converted ${\beta}$-oxoacyl-ACP to ${\beta}$-hydroxyacyl-ACP, the fabZ catalyzed the dehydration of ${\beta}$-3-hydroxyacyl-ACP to trans-2-acyl-ACP, and the fabI gene converted trans-2-acyl-ACP to acyl-ACP for long-chain fatty acids. In vivo productivity of total lipids and fatty acids was analyzed to confirm the changes and effects of the inserted genes in E. coli. As a result, lipid was increased 2.16-fold higher and hexadecanoic acid was produced 2.77-fold higher in E. coli JES1030, one of the developed recombinants through this study, than those from the wild-type E. coli.

• Journal of Microbiology and Biotechnology
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• v.25 no.4
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• pp.511-520
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• 2015

Triclosan, the widely used biocide, specifically targets enoyl-acyl carrier protein reductase (ENR) in the bacterial fatty acid synthesis system. Although the fish pathogen Aeromonas salmonicida subsp. salmonicida exhibits triclosan resistance, the nature of this resistance has not been elucidated. Here, we aimed to characterize the triclosan resistance of A. salmonicida subsp. salmonicida causing furunculosis. The fosmid library of triclosan-resistant A. salmonicida subsp. salmonicida was constructed to select a fosmid clone showing triclosan resistance. With the fosmid clone showing triclosan resistance, a subsequent secondary library search resulted in the selection of subclone pTSR-1. DNA sequence analysis of pTSR-1 revealed the presence of a chromosomal-borne fabV-encoding ENR homolog. The ENR of A. salmonicida (FabVas) exhibited significant homology with previously known FabV, including the catalytic domain YX₍₈₎K. fabVas introduction into E. coli dramatically increased its resistance to triclosan. Heterologous expression of FabVas might functionally replace the triclosan-sensitive FabI in vivo to confer E. coli with triclosan resistance. A genome-wide search for fabVas homologs revealed the presence of an additional fabV gene (fabVas2) paralog in A. salmonicida strains and the fabVas orthologs from other gram-negative fish pathogens. Both of the potential FabV ENRs expressed similarly with or without triclosan supplement. This is the first report about the presence of two potential FabV ENRs in a single pathogenic bacterium. Our result suggests that triclosan-resistant ENRs are widely distributed in various bacteria in nature, and the wide use of this biocide can spread these triclosan-tolerant ENRs among fish pathogens and other pathogenic bacteria.

• BMB Reports
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• v.30 no.4
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• pp.253-257
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• 1997

Negative ion fast atom bombardment (FAB) mass spectra were found to allow the determination of the linkage positions in a series of underivatized linkage-isomeric oligosaccharides. A previous work (Laine et al., 1988) reported that ion patterns of linkage-isomeric trisaccharides could be distinguished by a positive ion. Negative ion FAB collison-activated dissociation (CAD) mass spectrometry (MS) spectra of trisaccharides exhibited better sensitivity than the positive ion mode and provided specific fragmentation patterns according to the linkage positions. Especially, the fragmentations, m/z 205 in F6 and m/z 221 in G6, not occuring in 1-3 or 1-4 linkage. were an indication of 1-6 linkage, by changing collision energies from + 10 eV to +60 eV. The survival ratios of molecular ions in each collision energy set gave support to previous results in which the order of bond stability was 1-6>1-4>1-3 linkage.

• Korean Journal of Computational Design and Engineering
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• v.19 no.3
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• pp.214-223
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• 2014

This paper presents a bottleneck detection framework using simulation approach in a wafer FAB (Fabrication). In a semiconductor manufacturing industry, wafer FAB facility contains various equipment and dozens kinds of wafer products. The wafer FAB has many characteristics, such as re-entrant processing flow, batch tools. The performance of a complex manufacturing system (i.e. semiconductor wafer FAB) is mainly decided by a bottleneck. This paper defines the problem of a bottleneck process and propose a simulation based framework for bottleneck detection. The bottleneck is not the viewpoint of a machine, but the viewpoint of a step with the highest WIP in its upstream buffer and severe fluctuation. In this paper, focus on the classification of bottleneck steps and then verify the steps are not in a starvation state in last, regardless of dispatching rules. By the proposed framework of this paper, the performance of a wafer FAB is improved in on-time delivery and the mean of minimum of cycle time.

• BMB Reports
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• v.37 no.5
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• pp.556-564
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• 2004

A recombinant Fab monoclonal antibody (Fab) C37, previously obtained by phage display and biopanning of a random antibody fragment library against Burkholderia pseudomallei protease, was expressed in different strains of Escherichia coli. E. coli strain HB2151 was deemed a more suitable host for Fab expression than other E. coli strains when grown in media supplemented with 0.2% glycerol. The expressed Fab fragment was purified by affinity chromatography on a Protein G-Sepharose column, and the specificity of the recombinant Fab C37 towards B. pseudomallei protease was proven by Western blotting, enzyme-linked immunosorbent assay (ELISA) and by proteolytic activity neutralization. In addition, polyclonal antibodies against B. pseudomallei protease were produced in rabbits immunized with the protease. These were isolated from high titer serum by affinity chromatography on recombinant-Protein A-Sepharose. Purified polyclonal antibody specificity towards B. pseudomallei protease was proven by Western blotting and ELISA.

• Journal of the Korea Society for Simulation
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• v.32 no.3
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• pp.67-74
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• 2023

A semiconductor fabrication facility(FAB) is one of the most capital-intensive and large-scale manufacturing systems which operate under complex and uncertain constraints through hundreds of fabrication steps. To improve fab performance with intuitive scheduling, practitioners have used weighted-sum scheduling. Since the determination of weights in the scheduling significantly affects fab performance, they often rely on simulation-based decision making for obtaining optimal weights. However, a large-scale and high-fidelity simulation generally is time-intensive to evaluate with an exhaustive search. In this study, we investigated three sampling methods (i.e., Optimal latin hypercube sampling(OLHS), Genetic algorithm(GA), and Decision tree based sequential search(DSS)) for the optimization. Our simulation experiments demonstrate that: (1) three methods outperform greedy heuristics in performance metrics; (2) GA and DSS can be promising tools to accelerate the decision-making process.

• BMB Reports
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• v.44 no.4
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• pp.244-249
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• 2011

The quality of a phage-displayed antibody library deteriorates with clonal variations, which are caused by differentially expressed Escherichia coli antibody genes. Using the human Fab SP114 against the pyruvate dehydrogenase complex-E2 (PDCE2), we created four E. coli TOP10F' clones with a pCMTG phagemid encoding Fab-pIII (pCMTG-Fab), Fd ($V_H+C_{H1}$)-pIII (pCMTG-Fd), or light chain (L) (pCMTG-L), or the vector only (pCMTG-${\Delta}Fab$) to investigate the effect of clonal variations in a defined manner. Compared to the others, the E. coli clone with pCMTG-Fab was growth retarded in liquid culture, but efficiently produced phage progenies by Ex12 helper phage superinfection. Our results suggest that an antibody library must be cultured for a short duration before helper phage superinfection, and that the Ex12 helper phage helped to alleviate the detrimental effect of clonal variation, at least in part, by preferentially increasing functional phage antibodies during phage amplification.

• Bulletin of the Korean Chemical Society
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• v.32 no.1
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• pp.162-168
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• 2011

Many ligands have been experimentally designed and tested for their activities as inhibitors against bacterial enoyl-ACP reductase (FabI), ENR. Here the binding energies of the reported ligands with the E. coli ENR-$NAD^+$ were calculated, analyzed and compared, and their molecular dynamics (MD) simulation study was performed. IDN, ZAM and AYM ligands were calculated to have larger binding energies than TCL and IDN has the largest binding energy among the considered ligands (TCL, S54, E26, ZAM, AYM and IDN). The contribution of residues to the ligand binding energy is larger in E. coli ENR-NAD+-IDN than in E. coli ENR-$NAD^+$-TCL, while the contribution of $NAD^+$ is smaller for IDN than for TCL. The large-size ligands having considerable interactions with residues and $NAD^+$ have many effective functional groups such as aromatic $\pi$ rings, acidic hydroxyl groups, and polarizable amide carbonyl groups in common. The cation-$\pi$ interactions have large binding energies, positively charged residues strongly interact with polarisable amide carbonyl group, and the acidic phenoxyl group has strong H-bond interactions. The residues which have strong interactions with the ligands in common are Y146, Y156, M159 and K163. This study of the reported inhibitor candidates is expected to assist the design of feasible ENR inhibitors.