• Horticultural Science & Technology
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• v.19 no.3
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• pp.315-319
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• 2001

The study was carried out to develop a simple and efficient system to regenerate plants from cotyledon and hypocotyl tissues of Chinese cabbage (Brassica campestris L. ssp. pekinensis cv Seoul). Among the various combinations of naphthalene acetic acid (NAA) and 6-benzyladenine (BA) tested, the best shoot induction medium for cotyledon, with 2.67 shoots per explants, contained $2.0mg{\cdot}L^{-1}$ NAA, $1.0mg{\cdot}L^{-1}$ BA and $16.7mg{\cdot}L^{-1}$ $AgNO_3$. The shoot induction medium with $1.0mg{\cdot}L^{-1}$ NAA, $5.0mg{\cdot}L^{-1}$ BA and $16.7mg{\cdot}L^{-1}$ $AgNO_3$, was best for shoot induction from hypocotyl explants, with 1.87 shoots per explants. After shoot induction, regenerated shoots were excised and rooted on rooting medium. Rooted plantlets were then hardened in the high humidity growth chamber and transplanted to pots, and then grown in the greenhouse. Regenerated plants appeared phenotypically normal and there were no changes in chromosome number.

• Journal of Microbiology and Biotechnology
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• v.29 no.8
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• pp.1288-1298
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• 2019

Bacterial ATP synthases drive ATP synthesis by a rotary mechanism, and play a vital role in physiology and cell metabolism. Corynebacterium glutamicum is well known as an industrial workhorse for amino acid production, and its ATP synthase operon contains eight structural genes and two adjacent genes, cg1360 and cg1361. So far, the physiological functions of Cg1360 (GenBank CAF19908) and Cg1361 (GenBank CAF19909) remain unclear. Here, we showed that Cg1360 was a hydrophobic protein with four transmembrane helices (TMHs), while no TMH was found in Cg1361. Deletion of cg1360, but not cg1361, led to significantly reduced cell growth using glucose and acetic acid as carbon sources, reduced F1 portions in the membrane, reduced ATP-driven proton-pumping activity and ATPase activity, suggesting that Cg1360 plays an important role in ATP synthase function. The intracellular ATP concentration in the ${\Delta}cg1360$ mutant was decreased to 72% of the wild type, while the NADH and NADPH levels in the ${\Delta}cg1360$ mutant were increased by 29% and 26%, respectively. However, the ${\Delta}cg1361$ mutant exhibited comparable intracellular ATP, NADH and NADPH levels with the wild-type strain. Moreover, the effect of cg1360 deletion on L-valine production was examined in the L-valine-producing V-10 strain. The final production of L-valine in the $V-10-{\Delta}cg1360$ mutant reached $9.2{\pm}0.3g/l$ in shake flasks, which was 14% higher than that of the V-10 strain. Thus, Cg1360 can be used as an effective engineering target by altering energy metabolism for the enhancement of amino acid production in C. glutamicum.

• YAKHAK HOEJI
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• v.36 no.3
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• pp.230-240
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• 1992

The metabolic profile of doxylamine, N,N-dimethyl-2-[1-phenyl-1-(2-pyridinyl)ethoxy] ethanamine, was determined in the human urine. The free fractions of extracts were obtained without hydrolysis, and the conjugated fractions of extracts were obtained with enzyme hydrolysis using ${\beta}-glucuronidase/arylsulfatase$ from Helix pomatia. The mixture of acetic anhydride/pyridine (10 : 1, v : v) was used to derivatize the urinary extracts and then analyzed by gas chromatography and mass selective detector. N-desmethyldoxylamine, doxylamine carboxylic acid, desaminohydroxydoxylamine, N, N-didesmethyldoxylamine, N-acetyl conjugates of N-desmethyl and N, N-didesmethyldoxylamine, quarternary ammonium N-glucuronide of doxylamine, N-desmethyldoxylamine N-glucuronide and unchanged doxylamine were detected in the human urine obtained after oral treatment with doxylamine succinate. $N-methyl-{\alpha}-hydroxy-2-[1-phenyl-1-(2-pyridinyl)$ ethoxy] ethanamine, which can be a key intermediate of this metabolism, was tentatively identified by the interpretation of its mass spectrum. In this study, we proposed the metabolic pathway of doxylamine in the human on the basis of our data of the identified metabolites of doxylamine.

• Proceedings of the Microbiological Society of Korea Conference
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• 2002.10a
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• pp.27-30
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• 2002

Ralstonia eutrupha JMP134 is a well-known soil bacterium which can metabolite diverse aromatic compounds and xenobiotics, such as phenol, 2,4-dichlorophenoxy acetic acid (2, 4-D), and trichloroethylene (TCE), etc. Phenol is degraded through chromosomally encoded phenol degradation pathway. Phenol is first metabolized into catechol by a multicomponent phenol hydroxylase, which is further metabolized to TCA cycle intermediates via a meta-cleavage pathway. The nucleotide sequences of the genes for the phenol hydroxylase have previously been determined, and found to composed of eight genes phlKLMNOPRX in an operon structure. The phlR, whose gene product is a NtrC-like transcriptional activator, was found to be located at the internal region of the structural genes, which is not the case in most bacteria where the regulatory genes lie near the structural genes. In addition to this regulatory gene, we found other regulatory genes, the phlA and phlR2, downstream of the phlX. These genes were found to be overlapped and hence likely to be co-transcribed. The protein similarity analysis has revealed that the PhlA belongs to the GntR family, which are known to be negative regulators, whereas the PhlR2 shares high homology with the NtrC-type family of transcriptional activators like the PhlR. Disruption of the phlA by insertional mutation has led to the constitutive expression of the activity of phenol hydroxylase in JMP134, indicating that PhlA is a negative regulator. Possible regulatory mechanisms of phenol metabolism in R. eutropha JMP134 has been discussed.

• Korean Journal of Microbiology
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• v.6 no.2
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• pp.41-53
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• 1968

Studies on the carbohydrate metabolism of yeast as influenced by gamma-irradiation from cobalt-60 have been carried, then the mechanisms of radiation effect on respiration and fermentation were discussed under considerations of permeable changes of irradiated cell membrane. The cells of baker's yeast (Saccharomyces cerevisiae) which had been gamma-irradiated of 240 k.r. doses for an hour, then were put into aerobic oxidation and anaerobic fermentation without substrate. Total and fractionated carbohydrates of irradiated yeast cells were determined by calorimetric method with anthrone and orcinol reagents, the amounts of total carbohydrate, trehalose, RNA-ribose, PCA-soluble glycogen, alkali-soluble glycogen, acetic acid-soluble glycogen, mannan and glucan were determined according to the course of aerobic oxidation and anaerobic fermentation. It is found that the carbohydrates of irradiated cells leak out and amount of the losses teaches eleven times more than that of control, the volume of losses are seems to be replaced by water, it can be suggested the damage of gamma-irradiation occurs in the site of passive transport of cell membrane. The endogeneous aerobic respiration of irradiated cells are increased much more than control, the synthesis of reserve glycogen, glucan and RNA-ribose promoted much more than control. The anaerobic fermentation of irradiated cells are also increased than that of control, but the breakdown of carbohydrate is less than endogeneous respiration of irradiated cells. The synthetic rate is also less than that of aerobic oxidation. In irradiated yeast cells, trehalose is revealed to be primary substrate for endogeneous carbohydrate metabolism, so it is proved that the enzymic patterns are not changed but the activities of enzymes relating endogeneous respiration and autofermentation is activated. It is to be considerable to distiguish endogeneous respiration and autofermentation from exogeneous respiration and fermentation on irradiation, for membrane permeability changes and loses out carbohydrate by ionizing radiation.

• Journal of Nutrition and Health
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• v.33 no.8
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• pp.802-812
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• 2000

The purpose of this study was to examine the effect of resistant starch(RS) in hyperchlesterolemia and colon cancer. The subjects of this study was eight college women participating in the general starch diet(GSD) period for 5 days and resistant starch diet(RSD) period for 7 days. RSD contains 30g or the RS. On the last day of each program blood were collected. And for the last 3 days of each diet period, the amount of all the food consumed by the subjects and feces were collected. Food was measured to determine and compared the energy, protein and fat intakes. The amount of total cholesterol, HDL-cholesterol, LDL-cholesterol and volatile fatty acids in plasma and the amounts of bile acids in feces were measured by gas chromatography. The results obtained were as follows, Daily energy intake was higher in the RSD compared with the GSD, Protein and fat intakes were lower in the RSD compared with the compared with the GSD. Volatile fatty acid contents in plasma, the amounts of acetic acid, propionic acid and valeric acid were higher in the RSD compared with the GSD. The amounts of bile acids in feces, cholic acid, chenodeoxycholic acid and lithocholic acid were higher in the RSD compared with the GSD, But the amount of deoxycholic acid n the RSD period was significantly low. Secondary/primary ratios of bile acids was lower in the RSD compared with GSD, respectively. We speculate that , RS consumption decreases colonic mucosal proliferation as a result of the decreased formation of cytotoxic secondary bile acids. Thus, RS intakes may contribute the prevention of heart disease and colon cancer in humans. (Korean J Nutrition 33(8) : 802-812, 2000)

• Korean Journal of Poultry Science
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• v.18 no.2
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• pp.85-95
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• 1991

The investigation concerned an effect of the ground charcoal powder and organic acids on the digestibilities of protein and energy or the contents of uric acid, ammonia, creatine and urea in excreta of 113 week-old White Leghorn strain layers. Birds were fed basal (control) diet composed of mainly corn-soybean meal during a week of previous feeding and subsequent experimental diets during 12 weeks of experimental feeding . The experimental diets were the control diet(CON). diet(CPD) substituted 0.5% of the ground charcoal powder with the defatted rice bran of the CON, diet(PWV) added 0.1mM(based on the acetic acid) wood vinegar in the CPD and diet(PFA) added 0.1mM (based on the acetic acid) fermented acetic acid in the CPD. Birds fed CPD excreted significantly(P＜0.05) more fecal nitrogen(FN) and lower urinary nitrogen (UN) than those of birds fed CON. Digestibility of protein was lower significantly (P＜ 0.05) in CPB-fed bird than in bird fed CON. while birds fed CON. PWV and PFA showed similar values. Also urinary nitrogen per nitrogen intake (UN/NI) or absorbed nitrogen (UN/AN) was significantly (P＜0.05) lower in birds fed CPD compared with those in birds fed CON. And birds fed PWV tended to increase UN/NI and UN/AN, while PFA-fed birds excreted significantly (P＜0.05) higher UN/Nl and UN/Ah than those of birds fed CPD diet. The uric acid nitrogen (UAN) per nitrogen intake (UAN/NI) or absorbed nitrogen (UAN/AN) were lower significantly(P＜0.05) in CPD-fed birds and were tended to decrease in birds fed PWV compared with those in birds fed CON and PFA The ammoniacal nitrogen(AMN) per nitrogen intake (AMN/NI) or absorbed nitrogen (AMN/NI) was tended to increase in birds fed experimental diets and was increased significantly(P＜0.05) in birds fed PFA compared with those of birds fed CON. The excretion of creatine and urea nitrogen per nitrogen intake or absorbed nitrogen was shown similar values among birds fed experimental diets Digestibility of energy (DE/GE) was not shown any significant effect of experimental diet and were in the range of 80~84%. But metabolizability (ME/GE or MEn/GE) was increased in birds fed CPD and PWV and was decreased in birds fed PFA compared with those in birds fed CON. Although birds fed PWV showed significantly(P＜0.05) higher ME/GE than bird fed PFA, the MEn/GE were higher significantly (P＜0.05) in birds fed CON and CPD compared with that in birds fed PFA. Fecal energy affects 10~23% in the change of metabolizability though significant effect of fecal energy on the metabolizability were not found. But the effect of urinary energy on the metabolizability of diet was lowered as 2.3~3, 0% and the effect of experimental diets on the metabolizability of diets was due to change of urinary energy which also was originated from the change of uric acid energy.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.6
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• pp.944-950
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• 2015

The purpose of this study was to provide a basis for the management of traditional Doenjang by analyzing characteristics of volatile compounds in local Doenjang certified as a traditional food. The main compounds in Doenjang were acids, esters, aldehydes, and pyrazines, whereas relatively high intensities of acetic acid, ethyl alcohol, benzaldehyde, ethyl acetate, ethyl 2-methyl butanoate, 2,5-dimethyl pyrazine, and tetramethylpyrazine were detected among identified compounds. The analysis revealed that the composition of basic volatile compounds in Doenjang was similar, but isovaleric acid, 2-methylbenzaldehyde, tetramethylpyrazine, benzaldehyde, ethyl alcohol, ethyl caprylate, furfural and butanoic acid can serve as marker compounds for quality evaluation since they were specifically abundant in only some kinds of Doenjang. As a result, the quality status of Doenjang certified as a traditional food was determined by constructing a database of the volatile compounds, which can be suggested as a quality control method.

• KSBB Journal
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• v.27 no.4
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• pp.251-256
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• 2012

In this study we investigated the effect of temperature on the two-stage fermentation of Makgeolli using uncooked germinated black rice. The fermentation processes were conducted at $15^{\circ}C$ for three weeks and $25^{\circ}C$ for 7 days. The pH of Makgeolli at $25^{\circ}C$ increased from pH3.0 to pH 4.2, which was consistent with that at $15^{\circ}C$. In contrast total acidity of Makgeolli at $15^{\circ}C$ was about half of that at $25^{\circ}C$ (0.36% and 0.59%, respectively). By the 7 days-fermentation at $25^{\circ}C$, 11% of alcohol was produced, whereas three weeks were required for the same alcohol production at $15^{\circ}C$. In the case of sugar contents, the amounts of total glucose-equivalent reducing sugars and glucose increased at the end of the fermentation at $25^{\circ}C$ up to 2.25 mg/mL and 3.4 mM, respectively, whereas those at $15^{\circ}C$ were maintained at very low levels (0.18 mg/mL and 0.1 mM, respectively). Such limited supplement of sugars at $15^{\circ}C$ seemed to affect metabolism of yeast, resulting in different composition of organic acid. At $25^{\circ}C$, citric acid that was 73.4 ppm at the initial fermentation was consumed completely, whereas 20 ppm of citiric acid was remained at $15^{\circ}C$. In addition, acetic acid and lactic acid in Makgealli at $15^{\circ}C$ were 53% and 14% of those at $25^{\circ}C$.

• Proceedings of the Korean Society for Bioinformatics Conference
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• 2003.10a
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• pp.251-257
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• 2003

Metabolic engineering has become a new paradigm for the more efficient production of desired bioproducts. Metabolic engineering can be defined as directed modification of cellular metabolism and properties through the introduction, deletion, and modification of metabolic pathways by using recombinant DNA and other molecular biological tools. During the last decade, metabolic flux analysis(MFA) has become an essential tool fur metabolic engineering. By MFA, the intracellular metabolic fluxes can be quantified by the measurement of extracellular metabolite concentrations in combination with the stoichiometry of intracellular reactions and mass balances. The usefulness and functionality of MFA are demonstrated by applying to metabolic pathways in E. coli. First, a large-scale in silico E. coli model is constructed, and then the effects of carbon sources on intracellular flux distributions and succinic acid production were investigated on the basis of the uptake and secretion rates of the relevant metabolites. The results indicated that succinic acid yields increased in order of gluconate, glucose and sorbitol. Acetic acid and lactic acid were produced as major products rather than when gluconate and glucose were used carbon sources. The results indicated that among three carbon sources available, the most reduced substrate is sorbitol which yields efficient succinic acid production.