• Journal of Microbiology and Biotechnology
• /
• v.16 no.8
• /
• pp.1174-1179
• /
• 2006

The wild-type Corynebacterium glutamicum ATIC 13032 and Corynebacterium glutamicum ATTC 13032 lysC S301Y, exhibiting a deregulated aspartokinase, were compared concerning growth, lysine production, and intracellular carbon fluxes. Both strains differ by only one single nucleotide over the whole genome. In comparison to the wild-type, the mutant showed significant production of lysine with a molar yield of 0.087 mol (mol glucose$^{-1}$) whereas the biomass yield was reduced. The deregulation of aspartokinase further led to a global rearrangement of carbon flux throughout the whole central metabolism. This involved an increased flux through the pentose phosphate pathway (PPP) and an increased flux through anaplerosis. Because of this, the mutant revealed an enhanced supply of NADPH and oxaloacetate required for lysine biosynthesis. Additionally, the lumped flux through phosphoenolpyruvate carboxykinase and malic enzyme, withdrawing oxaloacetate back to the glycolysis and therefore detrimental for lysine production, was increased. The reason for this might be a contribution of malic enzyme to NADPH supply in the mutant in the mutant. The observed complex changes are remarkable, because they are due to the minimum genetic modification possible, the exchange of only one single nucleotide.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.30 no.6
• /
• pp.1171-1176
• /
• 2001

This study was undertaken to investigate the effect of Cassia tora ethanol extract on the lipid levels in serum and liver of rats fed high cholesterol diet. Experimental rats were divided into the following 4 groups: normal diet group, high cholesterol diet group, high choleslerol-0.25% C. tora ethanol extract group and high cholesterol-0.5% C. tora ethanol extract group. After 4 weeks, rats were sacrificed and analyzed the serum lipid profiles, activities of serum alanine aminotransferase (AST), aspartate aminotransferase (ALT), hepatic glucose-6-phosphate dehydrogenase (G6PDH) and malic enzyme (ME). It was also determined the contents of total cholesterol, triglyceride and thiobarbituric acid reactive substances (TBARS) in liver. There was no difference in weight gains between experimental groups. The concentrations of serum total cholesterol, free cholesterol, triglyceride and free fatty acid were tended to be decreased in C. tora groups compared with control group. HDL-cholesterol concentration was significantly decreased in high cholesterol diet group and slightly increased by C. tora ethanol extract feeding. The contents of liver cholesterol and triglyceride were higher in high cholesterol diet group than normal group, but significantly decreased by feeding of C. tora ethanol extract. Supplementation of 0.5% C. tora extract decreased significantly the activities of hepatic G6PDH and ME. Activities of serum AST, ALT and contents of liver TBARS were tended to be increased with high cholesterol diet and reduced by C. tora ethanol extract supplementation but had not significance. These results suggest that C. tora ethanol extract may exert a lipid lowering effect in serum and liver of rats.

• 한국생물공학회:학술대회논문집
• /
• 2000.11a
• /
• pp.665-668
• /
• 2000

Recombinant Escherichia coli NZN111 ($F-{\Delta}pfl::Cam$ ldhA::Kan) harboring pTrcML, a plasmid containing the E. coli malic enzyme gene, produced considerable amount of malic acid along with the desired product succinic acid. This seemed to be due to the unmatched redox states between glucose and succinic acid. Therefore, a more reduced carbon substrate sorbitol was examined for the possibility of matching the potential during succinic acid production. When NZN111 (pTrcML) was cultured in LB medium containing 20 g/L sorbitol under $CO_2$ atmosphere, 10 g/L of succinic acid was produced. The apparent yield of succinic acid was 1.1 g succinic acid per g sorbitol, which is 85% of the maximum theoretical yield.

• 한국생물공학회:학술대회논문집
• /
• 2005.10a
• /
• pp.585-585
• /
• 2005

• Proceedings of the Korean Society of Crop Science Conference
• /
• 1989.05a
• /
• pp.18-19
• /
• 1989

• Asian-Australasian Journal of Animal Sciences
• /
• v.16 no.3
• /
• pp.403-408
• /
• 2003

The study investigated the lipid metabolism of Tsaiya ducks under fasting and ad libitum feeding conditions. Sixty Tsaiya ducks in their growing period (8-12 wk-old) and sixty Tsaiya ducks in their laying period (26-30 wk-old, 10-14 weeks after the onset of laying) were randomly divided into ad libitum feeding and 3-day fasting groups. The activities of lipid metabolism related enzymes were determined. Experimental results indicated that fasting depressed the activities of lipogenesis related enzymes such as fatty acid synthetase and NADP-malic dehydrogenase in both periods (p<0.05). Fasting also increased the activities of liver fatty acid $\beta$-oxidation enzymes (p<0.05). However, the activities of lipoprotein lipase in adipose tissue, heart and ovarian follicle in both periods and the hormone-sensitive lipase of adipose tissue in the growing period were decreased by fasting (p<0.01).

• Preventive Nutrition and Food Science
• /
• v.4 no.3
• /
• pp.188-192
• /
• 1999

To study effects of methanol extract of prosomillet on lopid metabolism , five groups of male Sprang-Dawley rats weighing 116$\pm$9 g were fed test diets for four weeks. The five diets consisted of one low fat(5% w/w) diet containing starch as carbohydrate source(normal) and four high fat diets(15% w/w) containing 40.5%(w/w)sucrose(control) and additional 80% nethanol extractof prosomillet at the levels of 0.3% and 1%(w/w) or prosomillet powder at the level of 20%(w/w). Serum level of total cholesterol was a little higher but that of triglyceride was 41% lower in 20% (w/w) prosomillet powder group than in the control group. The cholesterol levels of two Liver cholesterol levels were lower and phospolipid levels higher in all three prosomillet powder group . Fecal excretionof bile acid was most increased in the prosomillet powder group among all five test groups. Acitivity of liver microsomal 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase was significantly lower in 0.3% methanol extract fed group than the control and also appeared to be reduced in 1% extract fed one, wherease those of 20 cholesterol 7$\alpha$-hydroxylase were not different among the five groups. Activities of liver cytosilic glucose-6-phosphate dehydrogenase(G6PDH) and malic enzyme were decreased in 0.3% prosomillet methanol extract and 20% powder groups. The results indicate that in addition to fiber, certain active components in prosomillet have potential to exert hypolipidemic effects via regulating hepatic cholesterogenesis and lipogenesis.

• Korean Journal of Microbiology
• /
• v.51 no.2
• /
• pp.169-176
• /
• 2015

The malolactic fermentation (MLF), which is widely used in winemaking, is the conversion of malic acid to lactic acid conducted by the malolactic enzyme (Mle) of lactic acid bacteria. In order to select the strains with MLF among 54 lactic acid bacteria isolated from the traditionally fermented foods, we designed a primer set that specifically targets the conserved regions of the mle gene and then selected four strains that harbor the mle gene of Lactobacillus plantarum. All strains were identified as L. plantarum by analyzing the 16S rRNA sequences, biochemical properties, and the PCR products of the recA gene. From comparison of the mle gene sequences consisting of 1,644 bp, the nucleotide and amino acid sequence of strain JBE60 correspond to 96.7% and 99.5% with those of other three strains, respectively. The strain JBE60 showed the highest resistant against 10% (v/v) ethanol among the strains. The strains lowered the concentration of malic acid to average 43%. Considering the ethanol resistance and conversion of malic acid, the strain JBE60 is considered as a potential starter for the malolactic fermentation.

• Korean Journal of Food Science and Technology
• /
• v.4 no.1
• /
• pp.1-5
• /
• 1972

This investigation was primarily carried out to establish the optimum conditions for the separation of sorbic acid, as an enzyme inhibitor, from dry mountain ash berries. The berries were crushed to $35{\sim}40\;mesh$, and leached with water to produce a reddish juice, which was concentrated to syrup after evaporation. Parasorbic acid was separated from the syrup by steam distillation in the presence of acid. In this study, the optimum experimental results for separation of parasorbic acid were obtained as follows : (1) the most applicable leaching time of the dry ash berries was about 6 hours at room temperature and less than 4 hours at $40^{\circ}C$ and (2) in steam distillation, after removal of malic acid, addition of 30 ml of sulfuric acid per 50 ml of syrup extracted from 100 g of the ash berries was very adequate. The purity of sorbic acid obtained experimentally through the isomerization technique was qualitatively examined by spectrophotometeric, paper chromatographic, and melting point measurements.

• Preventive Nutrition and Food Science
• /
• v.12 no.1
• /
• pp.51-57
• /
• 2007

The effects of maesil extract addition on the palatability and quality of kochujang, a traditional Korean condiment, were investigated in terms of the microbial characteristics, enzyme activities, and taste components during 100 days of fermentation. Viable cell counts of bacteria and yeast in maesil extract-added kochujang (maesil kochujang) were increased in proportion to added maesil extract from 1 to 5% during fermentation, up to 80 and 20 days, respectively and maintained $5.0{\sim}14.5{\times}10^6$ CFU/g. Activities of α-amylase, $\beta$-amylase, and protease were also increased in proportion to added maesil extract up to 20, 20, and 60 days, respectively and were higher than those of control during the aging process. The major organic acids in maesil kochujang were citric and malic acid. Composition and content of free sugar were not changed remarkably in general by the addition of maesil extract except maltose. The major free sugars of maesil kochujang were in the order of glucose>sucrose>maltose, and glucose content decreased significantly as the ratio of maesil extract increased, while maltose content increased significantly (p<0.05).