• Molecules and Cells
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• v.24 no.2
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• pp.185-193
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• 2007

Symbiotic nitrogen fixation with nitrogen-fixing bacteria in the root nodules is a distinctly beneficial metabolic process in legume plants. Legumes control the nodule number and nodulation zone through a systemic negative regulatory system between shoot and root. Mutation in the soybean NTS gene encoding GmNARK, a CLAVATA1-like serine/threonine receptor-like kinase, causes excessive nodule development called hypernodulation. To examine the effect of nts mutation on the gene expression profile in the leaves, suppression subtractive hybridization was performed with the trifoliate leaves of nts mutant 'SS2-2' and the wild-type (WT) parent 'Sinpaldalkong2', and 75 EST clones that were highly expressed in the leaves of the SS2-2 mutant were identified. Interestingly, the expression of jasmonate (JA)-responsive genes such as vspA, vspB, and Lox2 were upregulated, whereas that of a salicylate-responsive gene PR1a was suppressed in the SS2-2 mutant. In addition, the level of JA was about two-fold higher in the leaves of the SS2-2 mutant than in those of the WT under natural growth conditions. Moreover, the JA-responsive gene expression persists in the leaves of SS2-2 mutant without rhizobia infection in the roots. Taken together, our results suggest that the nts mutation increases JA synthesis in mature leaves and consequently leads to constitutive expression of JA-responsive genes which is irrelevant to hypernodulation in the root.

• Journal of Microbiology and Biotechnology
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• v.26 no.11
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• pp.1924-1932
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• 2016

Mycophenolic acid (MPA) is an antibiotic produced by Penicillium brevicompactum. MPA has antifungal, antineoplastic, and immunosuppressive functions, among others. ${\beta}-Hydroxy-{\beta}-methylglutaryl-CoA$ (HMG-CoA) lyase is a key enzyme in the bypass metabolic pathway. The inhibitory activity of HMG-CoA lyase increases the MPA biosynthetic flux by reducing the generation of by-products. In this study, we cloned the P. brevicompactum HMG-CoA lyase gene using the thermal asymmetric interlaced polymerase chain reaction and gene walking technology. Agrobacterium tumefaciens-mediated transformation (ATMT) was used to insert a mutated HMG-CoA lyase gene into P. brevicompactum. Successful insertion of the HMG-CoA lyase gene was confirmed by hygromycin screening, PCR, Southern blot analysis, and enzyme content assay. The maximum MPA production by transformants was 2.94 g/l. This was 71% higher than wild-type ATCC 16024. Our results demonstrate that ATMT may be an alternative practical genetic tool for directional transformation of P. brevicompactum.

• Bulletin of the Korean Chemical Society
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• v.27 no.4
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• pp.549-555
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• 2006

Acetohydroxyacid synthase (AHAS, EC 2.2.1.6 also referred to as acetolactate synthase) catalyzes the first common step in the metabolic pathway leading to biosynthesis of the branched-chain amino acids in plants and microorganisms. Due to its presence in plants, AHAS is a target for the herbicides (sulfonylurea and imidazolinone), which act as potent inhibitors of the enzyme. Recently, we have shown [J. Kim, D.G. Baek, Y.T. Kim, J.D. Choi, M.Y. Yoon, Biochem. J. (2004) 384, 59-68] that the residues in the “mobile loop” 567-582 on the C-termini are involved in the binding/stabilization of the active dimer and ThDP (thiamin diphosphate) binding. In this study, we have demonstrated the role of the W573 in the mobile loop of the C-termini of tobacco AHAS. The substitution of this W573 residue caused significant perturbations in the activation process and in the binding site of ThDP. Position W573 plays a structurally important role in the binding of FAD, maintaining the enzyme active site in the required geometry for catalysis to occur. In here we propose that the tryptophan at position 573 is important for the catalytic process.

• Journal of Ginseng Research
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• v.22 no.1
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• pp.51-59
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• 1998

In this study, rat hepatocytes known to have active glucose metabolism were obtained to investigate the hypoglycemic action of fat soluble fraction of red ginseng by using the liver perfusion technique and incubated in two different media-one containing insulin and glucagon (control group), and the other containing glucagon only The activities of main regulating enzymes, such as glucokinase, glucose 6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenate, and glucose 6-phosphatase, related to metabolic pathways of glucose in these two kinds of hepatocytes were compared between these two groups and the effects of addition of fat soluble fraction ($10^1$~$10^4$%) from red ginseng to these two groups on these enzymes were also detected. The results were as follows. The specific activity of enzymes such as glucokinase, flucorse 6-phosphate dehydrogenase, and 6-phosphogluconate dehydrogenase related to glucose-consuming pathways of insulin-deficient group was much less than control one. However, their decreased activity was recovered after the addition of fat-soluble fraction at all range of concentrations. The specific activity of these enzymes after the addition of ginseng components to the control group was also increased. On the other hand, the specific activity of glucose 6-phosphatase related to glucose-producing pathway of insulin-deficient group was much higher than control one, but their increased activity was decreased obviously after the addition of fat soluble fraction at all range of concentrations. The same results were observed after the addition of fat-soluble fraction to the control group. These results suggest that the red ginseng saponin components might be effective on diabetic hyperglycemia by regulating the activity of enzymes related to glucose metabolism directly and/or indirectly. The effects of fat-soluble fraction ($10^2$%) and ginsenosides (mixture, $Rb_1$ and $Rg_1$, $10^4$%) on hypoglycemic action were compared. As a result, they showed considerable effect on hyperglycemia, but the best eff ect on the activities of glucokinase and glucose 6-phosphate dehydrogenase was appeared by ginsenoside $Rb_1$ and that of 6-phosphogluconate dehydrogenase and glucose 6-phosphatase was by ginsenoside mixture.

• YAKHAK HOEJI
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• v.55 no.4
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• pp.301-308
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• 2011

Diabetes has been one of major health risks in industrialized countries. AMP-activated protein kinase (AMPK) has been focused as a novel therapeutic target for the treatment of metabolic syndromes, because AMPK increases glucose uptake through independent insulin signal pathway. In this study, we investigated the anti-diabetic effect of Angelica gigas Nakai extract (AGNEX), a mixture of decursin and decursinol angelate (53 : 47), decursin and decursinol angelate on blood glucose, glucose transport (GLUT) and AMPK expression levels in streptozotocin (STZ)-induced diabetic rats. To induce diabetes, 50 mg/kg of STZ was injected via i.v. route and AGNEX 2 mg/kg (STZ+AG), decursin 2 mg/kg (STZ+D), decursinol angelate 2 mg/kg (STZ+DA), and metformin 100 mg/kg (STZ+M) were administered orally for 21 days. STZ+DA group showed a significant decrease in fasting blood glucose levels compared to the other groups. Decursinol angelate significantly upregulated expression of glucose transporter 4 (GLUT4) and phosphorylation of AMPK (p-AMPK) in skeletal muscle of rats. In pancreas of rats, decursinol angelate significantly increased expression of GLUT2 through down-regulation of p-AMPK. In addition to the result of pancreatic islets morphology, AGNEX, decursin, decursinol angelate, and metformin treated group recovered ${\beta}$-cell damage by hyperglycemia. These results indicate that decursinol angelate might be a potential anti-diabetic agent and AGNEX could be useful in the treatment of diabetes mellitus.

• Archives of Pharmacal Research
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• v.27 no.2
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• pp.239-245
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• 2004

KR-31543, (2S,3R,4S)-6-amino-4-[N-(4-chlorophenyl)-N-(2 -methyl-2H-tetrazol-5-ylmethyl) amino]-3,4-dihydro-2-dimethoxymethyl-3-hydroxy-2-methyl-2H-1-benzopyran, is a new neuroprotective agent for preventing ischemia-reperfusion damage. This study was performed to identify the metabolic pathway of KR-31543 in human liver microsomes and to characterize cytochrome P450 (CYP) enzymes that are involved in the metabolism of KR-31543. Human liver microsomal incubation of KR-31543 in the presence of NADPH resulted in the formation of two metabolites, M1 and M2. M1 was identified as N-(4-chlorophenyl)-N-(2-methyl-2H-tetrazol-5-ylmethyl)amine on the basis of LC/MS/MS analysis with a synthesized authentic standard, and M2 was suggested to be hydroxy-KR-31543. Correlation analysis between the known CYP enzyme activities and the rates of the formation of M 1 and M2 in the 12 human liver microsomes have showed significant correlations with testosterone 6$\beta$-hydroxylase activity (a marker of CYP3A4). Ketoconazole, a selective inhibitor of CYP3A4, and anti-CYP3A4 monoclonal antibodies potently inhibited both N-hydrolysis and hydroxylation of KR-31543 in human liver microsomes. These results provide evidence that CYP3A4 is the major isozyme responsible for the metabolism of KR-31543 to M1 and M2.

• Clinical and Experimental Reproductive Medicine
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• v.21 no.3
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• pp.305-314
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• 1994

19-norandrostenedione(19-NORA) is known as an intermediate in the metabolic pathway from androstenedione to estrone. Administration of esterified 19-nortestosterone, anabolic steroid, reduces serum gonadotropin and testosterone concentration, and results in reversible azoospermia in men. 19-NORA have been isolated from testis, but its function in testis is not clear yet. Therefore, this study was designed to determine the effect of 19-NORA on steroidogenesis and on spermatogenesis. 19-NORA was administrated by single intratesticular injection to adult male rats weighing 350-400 g in dose of 1 mg/50${\mu}l$. The serum and testis were collected on 1, 3, 7, 12, 48 hr after injection. The histological differences in testis were observed by routine paraffin method. The concentrations of testosterone and estradiol in serum and in left testis were determined by the conventional radioimmunoassays. One hour after 19-NORA treatment, serum concentrations of testosterone and estradiol increased significantly, compared to those of pre-treated(0 hr) group, and reduced gradually to the control level on 7 hour after injection. The concentration of testosterone in left testis increased slightly 1 hour after injection, and estradiol level increased significantly(p<0.05). Also, testosterone and estradiol level of control group revealed no difference with pre-treated (0 hr) group. Gonad index, structure of seminiferous tubules, and the number of step 7 th spermatid were simillar to control group. The present study suggests that the elevation of testosterone level results from increment of estradiol followed by the rapid metabolism of 19-NORA at 7 hour after injection, and then testosterone concentration may be recovered to control level by feedback mechanism of hypothalamus-hypothysis-testis axis.

• Journal of Microbiology and Biotechnology
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• v.30 no.9
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• pp.1430-1435
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• 2020

Bacterial cellulose (BC) has outstanding physical and chemical properties, including high crystallinity, moisture retention, and tensile strength. Currently, the major producer of BC is Komagataeibacter xylinus. However, due to limited tools of expression, this host is difficult to engineer metabolically to improve BC productivity. In this study, a regulated expression system for K. xylinus with synthetic ribosome binding site (RBS) was developed and used to engineer a BC biosynthesis pathway. A synthetic RBS library was constructed using green fluorescent protein (GFP) as a reporter, and three synthetic RBSs (R4, R15, and R6) with different strengths were successfully isolated by fluorescence-activated cell sorting (FACS). Using synthetic RBS, we optimized the expression of three homologous genes responsible for BC production, pgm, galU, and ndp, and thereby greatly increased it under both static and shaking culture conditions. The final titer of BC under static and shaking conditions was 5.28 and 3.67 g/l, respectively. Our findings demonstrate that reinforced metabolic flux towards BC through quantitative gene expression represents a practical strategy for the improvement of BC productivity.

• Journal of Chest Surgery
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• v.25 no.7
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• pp.693-701
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• 1992

Extracorporeal cardiopulmonary bypass[CPB] has been associated with a wide variety of hematologic derangements, including a transient deformation and hemolysis of red blood cells[RBCs], which is supposed to be due to mechanical trauma and/or metabolic alterations. Since membrane integrity is, in part, maintained by energy requiring process, inadequate function of erythrocyte glycolytic pathway, which is inevitalble during CPB, may cause depletion of high energy phosphate pool and result in hemolysis. The authors performed an investigation to assess whether administration of Fructose-l, 6-diphsphate [FDP], which has been known to enhance intracellular glycolytic activities, could counteract erythrocyte hemolytic events caused by CPB. Sixty pateints with cyanotic congenital heart diseases, who underwent open heart surgery under CPB longer than 60 minutes, were randomly divided into two groups depending on whether use of FDP[Group FDP] or not[Group Control]. The age, sex, CPB time, preoperative hemoglobin level, disease entities were all similar[Table 1], and membrane type oxygenators were used in all patients. In Group, FDP, a dose of 250mg/kg body weight of FDP was administered by intravenous dripping every 12 hours from the morning of the operation to postoperative 48 hours, To demonstrate the degree and pattern of hemolysis of erythrocyte, reticulocyte count, indirect /direct bilirubin, haptoglobin, plasma hemoglobin, lactate dehydrogenase were measured every 12 hours from the time of cessation of CPB to 48 hours and RBC morphologic study, osmotic fragility test were done every 24 hours. All parameters revealed less hemolytic in group FDP [Fig. 1~5], though the differences between two groups were not significant, except plasma hemoglobin, lactate dehydrogenase changes. A pattern of sequential changes of plasma hemoglobin, lactate deh-ydrogenase showed the highest level at the time of CPB stop and abrupt decrease in following 24 hours in both groups, and statistically significant differences were demonstrated in group FDP at least for the first 12 hours postoperatively[p<0.05]. The authors conclude that they can expect the benificial effect of FDP on the maintenance of membrane stability of RBC probably by energy enhancement during the shock status of CPB, but FDP could not completely prevent the damaging effect on RBC by cardiopulmonary bypass

• Nutrition Research and Practice
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• v.10 no.1
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• pp.3-10
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• 2016

BACKGROUND/OBJECTIVES: Oligonol, mainly found in lychee fruit, is an antioxidant polyphenolic compound which has been shown to have anti-inflammatory and anti-cancer properties. The detailed mechanisms by which oligonol may act as an anti-aging molecule have not been determined. MATERIALS/METHODS: In this study, we evaluated the ability of oligonol to modulate sirtuin (SIRT) expression in human lung epithelial (A549) cells. Oligonol was added to A549 cells and reactive oxygen species production, mitochondrial superoxide formation, and p21 protein levels were measured. Signaling pathways activated upon oligonol treatment were also determined by western blotting. Furthermore, the anti-aging effect of oligonol was evaluated ex vivo in mouse splenocytes and in vivo in Caenorhabditis elegans. RESULTS: Oligonol specifically induced the expression of SIRT1, whose activity is linked to gene expression, metabolic control, and healthy aging. In response to influenza virus infection of A549 cells, oligonol treatment significantly up-regulated SIRT1 expression and down-regulated viral hemagglutinin expression. Oligonol treatment also resulted in the activation of autophagy pathways and the phosphorylation of AMP-activated protein kinase (AMPK). Furthermore, oligonol-treated spleen lymphocytes from old mice showed increased cell proliferation, and mRNA levels of SIRT1 in the lungs of old mice were significantly lower than those in the lungs of young mice. Additionally, in vivo lethality assay revealed that oligonol extended the lifespan of C. elegans infected with lethal Vibrio cholerae. CONCLUSIONS: These data demonstrated that oligonol may act as an anti-aging molecule by modulating SIRT1/autophagy/AMPK pathways.