• Journal of Microbiology and Biotechnology
• /
• v.33 no.4
• /
• pp.485-492
• /
• 2023

Methylorubrum extorquens, a facultative methylotroph, assimilates C₁ compounds and accumulates poly-β-hydroxylbutyrate (PHB) as carbon and energy sources. The ethylmalonyl pathway is central to the carbon metabolism of M. extorquens, and is linked with a serine cycle and a PHB biosynthesis pathway. Understanding the ethylmalonyl pathway is vital in utilizing methylotrophs to produce value-added chemicals. In this study, we determined the crystal structure of the mesaconyl-CoA hydratase from M. extorquens (MeMeaC) that catalyzes the reversible conversion of mesaconyl-CoA to β-methylmalyl-CoA. The crystal structure of MeMeaC revealed that the enzyme belongs to the MaoC-like dehydratase domain superfamily and functions as a trimer. In our current MeMeaC structure, malic acid occupied the substrate binding site, which reveals how MeMeaC recognizes the β-methylmalyl-moiety of its substrate. The active site of the enzyme was further speculated by comparing its structure with those of other MaoC-like hydratases.

• Korean Journal of Clinical Laboratory Science
• /
• v.49 no.3
• /
• pp.248-255
• /
• 2017

Increased hepatic enzymes are associated with insulin resistance, metabolic complications, and type 2 diabetes mellitus. Metabolically healthy obese (MHO) phenotype is not accompanied by metabolic complications and maintains insulin sensitivity, despite excessive body fat. The purpose of this study was to evaluate the clinical implications of hepatic enzymes in MHO men. The diagnostic criteria for MHO were based on NCEP-ATP III and obesity in adults was defined using WHO Asian-Pacific criteria. We used the data from 9,683 obese men aged between 20 and 70 years. The subjects were divided into three groups according to the diagnostic criteria: The metabolically healthy non-obese (MHNO, N=2,878), metabolically healthy obese (MHO, N=5,427), and metabolically abnormal obese (MAO, N=1,378). Obesity criteria were classified according to the standards set forth by WHO Asia-Pacific Criteria. AST, ALT, and GGT were significantly lower in the MHO group than in the MAO group (p<0.001, respectively). However, the hepatic enzyme levels were higher in the MHO group than in the MHNO group (p<0.001). Liver enzymes were associated with metabolic syndrome risk factors. Waist circumference, fasting glucose, total cholesterol, triglyceride, and HDL-C were risk factors for metabolic syndrome affecting liver enzymes. In conclusion, hepatic enzymes were found to predict metabolic abnormalities in metabolically healthy obese men.

• Bulletin of the Korean Mathematical Society
• /
• v.51 no.2
• /
• pp.339-356
• /
• 2014

In this paper, we introduce and discuss the notion of $D_C$-projective modules over commutative rings, where C is a semidualizing module. This extends Gillespie and Ding, Mao's notion of Ding projective modules. The properties of $D_C$-projective dimensions are also given.

• Archives of Pharmacal Research
• /
• v.9 no.2
• /
• pp.99-110
• /
• 1986

In order to use for metabolic studies of tranylcypromine (TCP), TCP-phenyl-$d_{5}$ was synthesized via the intermediates, 3-benzoylpropionic acid-$d_{5}$ and trans-2-phenylcyclopropanecarboxylic acid-$d_{5}$ -TCP(0.22 mmole/kg) and its deuterated analog were administered s. c. to the rats and GC/MS analyses of the urines led to the detection of N-acetyltranylcypromine (ATCP) and glucuronide conjugate of phenyl-hydroxylated ATCP. MAO activities in rat brain were measured using serotonin as the substrate. In vitro $IC_{50}$ of ATCP was determined to be $10^{-3}M$. The inhibitions by ATCP were not dependent on the preincubation time and were reversed by washing sedimented mitochondrial pellets after the preincubation. In vivo MAO inhibitions at various times of 0.5, 1.5, 3, 6, 12, and 23 hr after the administration of 0.4 mmole/kg (i. p. ) of ATCP were found to be 0.13, 73, 90, 89, and 74 %, respectively. Similarly, the inhibition percents by 0.015 mmole/kg (i. p. ) of TCP were 94, 99, 95, 91, 71 and 49%. The results strongly suggest that deacetylated product of ATCP may account for its in vivo MAO inhibition. The relationship between the metabolism via phenyl-hydroxylation and the in vivo potency of TCP was examined by QSAR study and it was found that groupings discriminating between the compounds with p-substituents and those without them only ensure high correlations, suggesting that ring-hydroxylation which occurs at the para position in most of the compounds is a determining factor to the potency of TCP.

• Advances in materials Research
• /
• v.6 no.3
• /
• pp.303-316
• /
• 2017

In this article, novel olefin polymerization catalyst with lower cost and simple synthetic process were developed, $ArOTiCl_3$ complexes [$(2-OMeC_6H_4O)TiCl_3(C1)$, $(2,4-Me_2C_6H_3O)TiCl_3(C2)$, $TiCl_3(1,4-OC_6H_4O)TiCl_3(C3)$, $TiCl_3(1,4-OC_6H_2O-Me_2-2,5)$ $TiCl_3(C4)$] and corresponding $(ArO)_2TiCl_2$ complexes [$TiCl_2(OC_6H_4-OMe-2)_2(C5)$ and $TiCl_2(OC_6H_3-Me_2-2,6)_2(C6)$] have been synthesized by the reaction of $TiCl_4$ with phenol, all these complexes were well characterized with $^1H$ NMR, $^{13}C$ NMR, MASS and EA. When combined with methylaluminoxane (MAO), the $ArOTiCl_3/MAO$ system shows high activity for ethylene copolymerization with 1-octene and copolymer was obtained with broaden molecular weight distribution (MWD). The $^{13}C$ NMR result of polymer indicates that the 1-octene incorporation in polymer reached up to 8.29 mol%. The effects of polymerization temperature, concentration of polymerization monomer and polymerization time on the catalytic activity have been investigated.

• 한국신재생에너지학회:학술대회논문집
• /
• 2011.11a
• /
• pp.83.2-83.2
• /
• 2011

In this study, we fabricated tubular ceramic support for segmented-in-series solid oxide fuel cell (SOFC) by using MAO(MgAl-stabilized ) as main material and activated carbon as pore former. Thermal expansion properties of ceramic support with different amounts of activated carbon were analyzed by using dilatometer to decide a suitable sintering temperature. The tubular ceramic supports with different amounts of activated carbon (15, 20, 30wt.%) were fabricated by the extrusion technique. After sintering at $1400^{\circ}C$ for 2h, cross section and surface morphology of tubular ceramic support were analyzed by using SEM image. Also, the porosity, mechanical property, gas permeability of tubular ceramic supports was measured. Based on these results, we established the suitable fabrication technique of tubular ceramic support for segmented-in-series SOFC.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2007.04a
• /
• pp.126-127
• /
• 2007

AZ91D 마그네슘합금상에 MAO방법을 통한 산화막 성장에 관해 연구하였다. 주요 처리조성물은 NaOH, $Na_3\;C_6H_5O_7$, $Na_4\;P_2\;O_7$이며, 양극에 Mg 샘플을, 음극에 스텐레스 플레이트를 고정하여 설치후 인가전압 50V, 2분간에 걸쳐 Mg 표면에 Micro arc에 의한 산화막이 성장되었다. 산화막 측정 결과 20회 시행후 평균 15.5um 두께를 가졌으며, 막 성장후 표면은 균일하였으며, 밝은 갈색을 띄었다. 염수농도 5%의 염수분무테스트에서는 72시간 경과후에도 5%이내의 우수한 내부식성을 보였다.

• Journal of the Korean Chemical Society
• /
• v.54 no.1
• /
• pp.23-26
• /
• 2010

A Schiff base ligand (Z)-N-((Z)-2-(sec-butylimino)-1,2-diphenylethylidene)butan-2-amine was synthesized by condensation of benzil with sec-butyl amine. Complexation of the ligand was carried out with first row transition elements, manganese(II) and nickel(II). Ligand and complexes were characterized by FTIR, elemental analysis and thermogravimetric analysis in solid state and by NMR ($^1H,\;^{13}C$) in solution form. Both the complexes demonstrate good catalytic activity for butadiene oligomerization under mild conditions with methylaluminoxane (MAO) as co-catalyst.

• BMB Reports
• /
• v.37 no.4
• /
• pp.439-444
• /
• 2004

Double stranded targets on the cDNA microarray contain representatives of both the coding and noncoding strands, which will introduce hybridization competition with probes. Here, the effect of double and single strands of targets on the signal intensity and the ratios of Cy5/Cy3 within the same slide were compared. The results show that single stranded targets can increase the hybridization efficiency without changing the Cy5/Cy3 ratio. Based on these results, a new strategy was established by generating cDNA targets with asymmetric PCR, instead of conventional PCR, to increase the sensitivity of the cDNA microarray. Furthermore, the feasibility of this approach was validated. The results indicate that the cDNA microarray system based on asymmetric PCR is more sensitive, with no decrease in the reliability and reproducibility as compared with that based on conventional symmetric PCR.

• Journal of Life Science
• /
• v.23 no.7
• /
• pp.933-940
• /
• 2013

The aim of this work was to determine the chemical composition of essential oil from aerial partsof Mentha arvensis L. f. piperascens (MAO) and to evaluate the effect of its fragrant chemicals on electroencephalographic (EEG) activity of human brain. The MAO was obtained by supercritical $CO_2$ extraction. The maximum yield was 2.38% at conditions of $70^{\circ}C$ and 200 bar. There were 32 volatile chemicals with 6 alcohols (67.11%), 13 hydrocarbons (17.05%), 9 esters (11.50%), 2 ketones (7.16%), 1 oxide (2.77%), and 1 aldehyde (0.56%). The major components were (Z,Z,Z)-9,12,15-octadecatrien-1-ol (50.06%), 2-hydroxy-4-methoxyacetophenone (7.50%), and 3,4-dihydro-8-hydroxy-3-methyl-1H-2-benzopyran-1-one (6.60%). Results of the EEG study showed that inhalation of MAO significantly changed the EEG power spectrum values of relative gamma, relative fast alpha, and spectral edge frequency 90%. During the inhalation of MAO, the value of relative fast alpha was significantly increased (p<0.05). On the other hand, the values of gamma and the spectral edge frequency 90% were significantly decreased (p<0.05). The present study suggests that fragrant chemicals of essential oil of M. arvensis reduce the level of mental stress and that they could be used in the treatment of psychophysiological disorders.