• Microbiology and Biotechnology Letters
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• v.15 no.6
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• pp.396-401
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• 1987

Protein productivities of a cloned gene ($\beta$-galactosidase) and the cultural performances of two recombinant Escherichia coli strains, which use different host-vector systems, were studied. E. coli JM109/pTBG10 strain which carries Tac promoter had higher protein productivity than E. coli MH3000 (pRKc1857)/pASI(lacZ) strain which carries pL promoter. Induction of protein syn-thesis was optimum at the initial-and mid-logarithmic growth phases for both strains. Oxygen demand was observed to be very high during the cloned gene expression, and could be alleviated to some extent through pH control. The ratio of specific growth rates of plasmid-harboring to plasmidfree cell, $\mu$+ /$\mu$-, of the high productivity strain was observed to be lower than that of the low productivity one. Plasmid stability was analyzed for 20-30 generations, and it was found that the traction of plasmid-harboring cells dropped to l0% level in about 25 generations for both strains when the cloned gene expression was induced.

• Journal of Crop Science and Biotechnology
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• v.11 no.4
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• pp.249-256
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• 2008

The objective of this work was to evaluate the germination of 12 rice genotypes under propionic acid stress, a phytotoxic compound produced in low drainage soils with high organic matter content. The tests were conducted with the first count of germination (PCG) and germination (G) of the genotypes subjective to 0, 3, 6, and 9 mM propionic acid concentrations. The seeds of each genotype were placed in germitest paper pre-soaked in treatment solutions forming individual bags. The germination was performed at $25^{\circ}C$ and the counts were carried out at 7 (PCG) and 14 days (G). A factorial random block design was performed with four replications of 50 seeds per genotype. Our study revealed that doses up to 9 mM propionic acid in the pre-soaking solution were efficient for genetic variability studies involving the character germination in rice; genetic variability for germination was detected in the collection of rice genotypes when subjected to propionic acid toxic effects. The genotypes Guichow, Dawn, and Toride-1 showed germination stability when subjected to increasing levels of propionic acid, and genotypes originated from irrigated system-cultivation performed better when subjected to propionic acid stress. These three genotypes will be a good biological material to for enhance the resistance to phytotoxic compounds in rice.

• The Korean Journal of Food And Nutrition
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• v.24 no.2
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• pp.153-158
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• 2011

This study was performed to develop new anti-obesity agents from medicinal plants for functional food industry. We prepared lipase inhibitor-containing ethanol extracts from Desmodium oxyphyllu DC. and its nutritional characteristics, stability of temperature and pH and physiological functionalities were investigated. Crude lipid content and curde protein content of ethanol extract from Desmodium oxyphyllum DC. were 26.5% and 5.7%, respectively and its asparagine content was 4,860 mg/100 g, dry basis. The ethanol extracts were also stable from pH 3.0 to pH 9.0 and below $80^{\circ}C$. The ethanol extract were showed high lipase inhibitory activity of 74.2% and acetylcholinesterase inhibitory activity of 68.4%.

• Genomics & Informatics
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• v.12 no.2
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• pp.71-75
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• 2014

The tRNA structure contains conserved modifications that are responsible for its stability and are involved in the initiation and accuracy of the translation process. tRNA modification enzymes are prevalent in bacteria, archaea, and eukaryotes. tRNA Gm18 methyltransferase (TrmH) and tRNA $m^1G37$ methyltransferase (TrmD) are prevalent and essential enzymes in bacterial populations. TrmH involves itself in methylation process at the 2'-OH group of ribose at the 18th position of guanosine (G) in tRNAs. TrmD methylates the G residue next to the anticodon in selected tRNA subsets. Initially, $m^1G37$ modification was reported to take place on three conserved tRNA subsets ($tRNA^{Arg}$, $tRNA^{Leu}$, $tRNA^{Pro}$); later on, few archaea and eukaryotes organisms revealed that other tRNAs also have the $m^1G37$ modification. The present study reveals Gm18, $m^1G37$ modification, and positions of $m^1G$ that take place next to the anticodon in tRNA sequences. We selected extremophile organisms and attempted to retrieve the $m^1G$ and Gm18 modification bases in tRNA sequences. Results showed that the Gm18 modification G residue occurs in all tRNA subsets except three tRNAs ($tRNA^{Met}$, $tRNA^{Pro}$, $tRNA^{Val}$). Whereas the $m^1G37$ modification base G is formed only on $tRNA^{Arg}$, $tRNA^{Leu}$, $tRNA^{Pro}$, and $tRNA^{His}$, the rest of the tRNAs contain adenine (A) next to the anticodon. Thus, we hypothesize that Gm18 modification and $m^1G$ modification occur irrespective of a G residue in tRNAs.

• Korean Journal of Plant Resources
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• v.28 no.1
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• pp.135-144
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• 2015

The Korean daily intake of vegetable oils has increased about 2.5-fold from 17 g/day to 46 g/day for the last several decades. Perilla (Perilla frutescens var. frutescens) has been cultivated in Korea for a long time as a dietary oil seed which has the highest content of ${\alpha}$-linolenic acid, accounting for nearly 60%. It is known that the main role of ALA is as a precursor to the longer-chain ${\omega}-3$, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), the metabolic products of ${\alpha}$-linolenic acid (ALA, ${\omega}-3$). Dietary ${\omega}-3$ fatty acids reduce inflammation and the risk of chronic diseases such as heart disease, cancer, and arthritis, but they also may act as functional components for cognitive and behavioral function. Thus, ${\alpha}$-linolenic acid is one of the essential nutrients in modern dietary patterns in which much linoleic acid is consumed. Nevertheless, perilla oil, rich in ${\alpha}$-linolenic acid, can be easily oxidized, giving rise to controversies with respect to shelf life, the deterioration of the product's commercial value, and further related toxicity. Recent research using genetic modifications has tried to develop new plant oil seeds that balance the ratio of ${\omega}-6/{\omega}-3$ fatty acids. Such trials could be a strategy for improving an easily oxidizable property of perilla oil due to high ${\alpha}$-linolenic acid. Alternatively, appropriate application of antioxidant to the oil can be considerable.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.6
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• pp.40-50
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• 2002

In this paper, we present a GA(Genetic Algorithm) approach to select weighting matrices of an optimal LQ(Linear Quadratic) controller for SVC(Static VAR Compensator). A SVC, one of the FACTS(Flexible AC Transmission System), constructed by a FC(Fixed Capacitor) and a TCR(Thyristor Controlled Reactor), was designed and implemented to improve the damping of a synchronous generator, as well as to control the system voltage Also, a design of LQ controller depends on choosing weighting matrices. The selection of weighting matrices which is not a trivial solution is usually carried out by trial and error. We proposed an efficient method using GA of finding weighting matrices for optimal control law. Thus, we proved the usefulness of proposed method to improve the stability of single machine-infinite bus with SVC system by eigenvalues analysis and simulation.

• Journal of Korean Society of Steel Construction
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• v.18 no.2
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• pp.147-160
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• 2006

GA-based fuzzy optimum design algorithm incorporated with the refined plastic hinge analysis method is presented in this study. In the refined plastic hinge analysis method, geometric nonlinearity is considered by using the stability functions of the beam-column members. Material nonlinearity is also considered by using the gradual stiffness degradation model, which considers the effects of residual stresses, moment redistribution through the occurence of plastic hinges, and the geometric imperfections of the members. In the genetic algorithm, the tournament selection method and the total weight of the steel frames. The requirements of load-carrying capacity, serviceability, ductility, and constructabil ity are used as the constraint conditions. In fuzzy optimization, for crisp objective function and fuzzy constraint s, the tolerance that is accepted is 5% of the constraints. Furthermore, a level-cut method is presented from 0 to 1 at a 0 .2 interval, with the use of the nonmembership function, to solve fuzzy-optimization problems. The values of conventional GA optimization and fuzzy GA optimization are compared in several examples of steel structures.

• Korean Journal of Plant Resources
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• v.36 no.5
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• pp.496-507
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• 2023

The in vitro organogenesis is one of important issues in plant embryology, and somaclonal variations are existing in calli and/or regenerants induced from a process of the organogenesis with in vitro circumstances. In this study, expressions of organogenesis-related genes were evaluated and genetic stability of regenerants derived from the process of in vitro organogenesis were measured using ISSR markers in Imperata cylindrica 'Rubra', Poaceae. The expressions of organogenesis-related genes were detected all of regenerants at the process of the organogenesis. All ISSR markers produced with an average of 71 bands per in vitro-cultured regenerants, and the scorable bands were varied from two to eight with an average of 5.14 bands per a primer. The polymorphism rates of the in vitro regenerants were higher than that of mother plants (1.4%), showing 4.1% (pot-cultured regenerants), 4.3% (field-cultured regenerants), 4.2% (in vitro-cultured regenerants), 5.6% (calli with green shoots) and 1.4% (calli), respectively. The genetic similarity matrix (GSM) among all accessions ranged from 0.747 to 1.0 with a mean of 0.868. GSM of the regenerants showed differences (from 0.972 to 1.00) compared with that of mother plants (0.991). According to the clustering analysis, two independent groups were divided into; the one is mother plants and regenerants cultured at room and open field, the other is regenerants cultured in vitro. The results give a new insight for understanding the dynamics of organogenesis in monocot plant.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.8
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• pp.417-428
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• 2020

Housekeeping genes are expressed in cells of all organisms and perform basic cellular functions such as energy generation, substance synthesis, cell death, and cell defense. Accordingly, the expression levels of housekeeping genes are relatively constant, and thus they are used as reference genes in gene expression studies, such as protein expression and mRNA expression analysis of target genes. However, the levels of expression of these genes may be different among various tissues or cells and may change under certain circumstances. Therefore, it is important to select the best reference gene for specific gene expression research by exploring the stability of housekeeping gene expression. This review summarizes housekeeping genes found in humans, chickens, pigs, and rats in the literature and estimates expression stability using geNorm, NormFinder, and BestKeeper software. The most suitable reference housekeeping gene can selected based on expression stability according to the experimental conditions of the gene expression study and can thus be applied to data normalization.

• Journal of Microbiology and Biotechnology
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• v.24 no.2
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• pp.197-208
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• 2014

A novel protease gene from Bacillus gibsonii, aprBG, was cloned, expressed in B. subtilis, and characterized. High-level expression of aprBG was achieved in the recombinant strain when a junction was present between the promoter and the target gene. The purified recombinant enzyme exhibited similar N-terminal sequences and catalytic properties to the native enzyme, including high affinity and hydrolytic efficiency toward various substrates and a superior performance when exposed to various metal ions, surfactants, oxidants, and commercial detergents. AprBG was remarkably stable in 50% organic solvents and retained 100% activity and stability in 0-4 M NaCl, which is better than the characteristics of previously reported proteases. AprBG was most closely related to the high-alkaline proteases of the subtilisin family with a 57-68% identity. The secretion and maturation mechanism of AprBG was dependent on the enzyme activity, as analyzed by site-directed mutagenesis. Thus, when taken together, the results revealed that the halo-solvent-tolerant protease AprBG displays significant activity and stability under various extreme conditions, indicating its potential for use in many biotechnology applications.