• Applied Biological Chemistry
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• v.30 no.1
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• pp.77-87
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• 1987

The mutant with high productivity, X. malvacearum SNUF 560-6, was acquired from the X. malvacearum SNUF 560 with low productivity by UV-light irradiation. It was preserved is lyophilized stock culture and it was transferred to PDA slant to maintain viability fortnightly. Fermentations were started by retransfering to MY agar slant from PDA stok culture. The experiments for optimal xanthan gum production were studied in a chemically defined medium. Of the carbon and nitrogen sources tested, 0.4% sucrose medium and 10mM glutamic acid medium yielded the highest xanthan gun production respectively. The addition of 10g/l succinic acid stimulated xanthan gum production. Also 65mM $PO_4\;^{-3}\;(12.6g/l\;KH_2PO_4)$ was effective on xanthan gum production. Finally, medium 1 and medium 2 which have high xanthan gum production potencies were achieved in this stud. The components of medium 1 and medium 2 were as follows: Medium 1 : sucrose 40g/l glutamate 10mM $PO_4\;^{-3}\;54mM\;(KH_2PO_4\;12.65g/l)$ Citrate 2g/l $MgSO_4{\cdot}7H_2O\;0.2g/l$ $H_3BO_3\;0.005/l$ ZnO 0.006/l $FeCl_2{\cdot}6H_2O\;0.0024g/l$ $CaCO_3\;0.02g/l$ Medium 2 : $Sucrose\;40g/l\;(NH_4)_2SO_4\;2g/l$ $PO_4\;^{-3}\;65mM\;(KH_2PO_4\;12.65g/l)$ Succinate 10g/l $MgSO_4{\cdot}7H_2O\;0.02g/l$ $H_3BO_3\;0.06g/l$ ZnO 0.006g/l $FeCl_2{\cdot}6H_2O\;0.0024g/l$ $CaCO_3\;0.02g/l$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.6
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• pp.1145-1150
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• 2000

면역증강물질을 생산하는 균주를 해수로부터 분리하여 동정한 결과 크림색의 둥근 점질성의 집략을 나타내었으며, Gram 음성의 간산형이고, 미약한 운동성을 가지며 catalase 양성과 oxidase 음성 반응을 보였다. 균주를 6시간 , 20시간, 72시간, 및 144시간 뱅양하여 전자 현미경사에서 관찰한 결과 20시간 배양한 영양세포는 1.25~0.6$\times$0.6$\mu\textrm{m}$ 크기의 간균 형태를 갖추었으며 시간이 흐를수록 세포내 관립의 밀도가 증가하면서 세포형태가 다형태성으로 변하였다. 세포내 과립의 존재를 확인하기 위해 sudan black B로 염색한 결과 양성으로 polyhy-droxy butyrate로 예상되었다. 생육을 위한 최적 온도는 3$0^{\circ}C$, pH는 3.0~10.0이었으며, 호기성균이었다. D-Glu-cose, D-mannose, D-mannitiol. insitol, maltose 등의 당과 L-asparagine, L-glutamate 등의 아미노산을 이용하였고 특시, O/F test에서 glucose와 maltose를 산화 하였다. 이상과 같은 결과로 해양세균 유래인 Pseudo-mallei group의 Burkholderia 속으로 확인되었음로 본 균주를 Burkholderia sp. IS-203으로 명명하였다.

• Journal of Biomedical Engineering Research
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• v.12 no.1
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• pp.57-62
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• 1991

ABA type block copolymers composed of poly($\gamma-benzyl$ L-glutamate) (PBLG) as the A component and poly (ethylene glycol) as the B component were obtained by polymerization of $\gamma-benzyl$ L-gletamate N -carboxyanhydride, initiated by amino groups at both ends of poly(ethylene glycol) . From circular dichroism measurements in ethylene dichloride solution as well as from infrared spectTa measurements in solid state, it was found that the polypep- tide block exists in the a-helical conformation, as in PBLG homopolymer. $Poly-N^5$ (3-hydroxypropyl glutamine) (PHPG)/poly(ethylene glycol)block copolymer hydrogel was obtained by the treatment of PBLG/PBG block copolymer with the mixture of 3-ammine-1-propanol and diamlnooctane. The water content of PHPG/PEG block copolymer hydrogel was about 80wt% when the concentration of crosslinking agent was below 5 mole % per polymer.

• Journal of Applied Biological Chemistry
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• v.48 no.1
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• pp.32-34
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• 2005

Arils of Euporia longana L. was extracted with 80% aqueous MeOH and partitioned successively with EtOAc, n-BuOH and $H_2O$. From the n-BuOH fraction, furan compound was isolated through silica gel column chromatography. The results of physico-chemical data including NMR, MS and IR revealed the compound to be 5-(hydroxymethyl)-2-furfuraldehyde. This compound stimulated GDH I activity by $19.2{\pm}0.6$, $41.2{\pm}0.9$, $68.4{\pm}1.1$, $80.3{\pm}0.9$ and $85.9{\pm}1.6%$ at in vitro concentrations of 0.005, 0.008, 0.02 and 0.03 %, respectively.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.313-316
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• 2000

The effects of initial sugar concentration and the various nitrogen sources on the fermentation characteristics of Thraustochytrium aureum were investigated. The sugar conversion ratios decrease with increase in the initial sugar concentration regardless of the kinds of nitrogen sources. The specific growth rate, the biomass yield, and the DHA yield also decreased but approached constant values higher than the concentration of 30g/L. The sugar conversion ratios and the specific growth rate showed the highest values in case of using the yeast extract as nitrogen source. It was difficult to conclude that the variation of nitrogen source had some effects on the biomass yield. However, the initial sugar concentration had a rather effects on the biomass yield for the sugar concentration of 40 g/L showed 0.27. The nitrogen source that showed the greatest yield of DHA was sodium glutamate.

• Macromolecular Research
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• v.14 no.3
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• pp.387-393
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• 2006

Nanoparticles of Poly(L-glutamic acid) (PG) conjugated to the anticancer drug paclitaxel and targeted moiety folic acid (FA) were synthesized and characterized in vitro. The nanoparticles were designed to take advantage of FA targeting to folate receptor (FR) positive cancer cells. The chemical composition of the conjugate was characterized by $^1H-NMR$, FTIR and UV/vis spectroscopy. The selective cytotoxicity of the FA-PG-paclitaxel conjugates was evaluated in FR positive cancer cells. The interaction of the conjugate was visualized by fluorescence microscopy with results confirming the successful preparation of the conjugate and the production of nanoparticles of about 200-300 nm in diameter. The amount of paclitaxel conjugated to FA-PG was 25% by weight. Cellular uptake of the conjugate was FA dependent, and the conjugate uptake was mediated specifically by the folate receptor. These results demonstrate the improved selective toxicity and effective delivery of an anticancer drug into FR bearing cells in vitro.

• Microbiology and Biotechnology Letters
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• v.20 no.1
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• pp.79-84
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• 1992

The Photosynthetic bacterium, Rhodopseudomonas sphaeroides strain B6 was irnmobilized on agar gel. The optimum concentration of agar for hydrogen production was 2% (w/v). Maximum rates of hydrogen production by immobilized (300 ml of gel; 2.85 rng dry cells/ml) and free cells (1l culture; 0.87 mg dry cells/ml) were 47.5 and 48.0 ml/hr/culture, respectively. However, when both cultures were fed by 10 mmoles of lactate as limited electron donor at the later period of incubation, the activity of hydrogen production by free cells was significantly decreased but, immobilized cells continued hydrogen production with almost the same initial rate. Wc examined hydrogen production by immobilized cells of strain B6 under periodic illumination for 12 hr-intervals. When the culture was periodically fed by basal medium containing 9.3 rnmoles of DL-lactate and 1.86 mmoles of L-glutamate as consumed electron donor and nitrogen source, respectively, for every one liter of hydrogen produced, hydrogen was evolved continuously with the average rate of 510 ml/day/300 ml gel (2.9 rng dry cellslml) during the incubation time for 228 hr.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.5
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• pp.455-463
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• 1985

Thermal-denaturation of myofibrillar protein of dorsal skeletal muscle from file fish was investigated by measuring denaturation constant($K_D$) and thermodynamic parameters at various temperatures. The protective effects of sucrose, sorbitol and amino acids when added individually or combined were also discussed. The denaturation rate as reflected in inactivation of myofibrillar protein Ca-ATPase was followed the first order reaction. The $K_D$ values at $25^{\circ}C,\;30^{\circ}C,\;and\;35^{\circ}C$ were $19.52{\times}10^{-5},\;112.25{\times}10^{-5},\;and\;247.20{\times}10^{-5}$, respectively. The activation energy of the reaction at $30^{\circ}C$ was 43 kcal/mole. The protective effects of sucrose, sorbitol, glycine, alanine and Na-glutamate were increased with the concentration but the effects of sorbitol and Na-glutamate decreased beyond 1.0 mole. Basic amino acids such as arginine and lysine did not revealed any protective effect on the thermal denaturation. In case of mixed addition, the effects of Na-glutamate to glycine, sorbitol to glycine, and sorbitol to sucrose or sorbitol to Na-glutamate were enhanced 1.2 to 7.0 times as much as that of control (ratio of mixing; 1:1, range of concentration; 0.5 to 1.25 mole). Under the frozen condition at $-20^{\circ}C$, two mixtures such as Na-glutamate to glycine and sorbitol to sucrose apparently revealed the protective effects.

• Korean Journal of Microbiology
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• v.31 no.3
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• pp.237-244
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• 1993

Aspartate aminotransferase (ASAT) (L-aspartate : 2-oxyoglutarate, EC 2.6. 1. 1.) from Streptomyces fradiae NRRL 2702 has been purified by acetone precipitation, DEAE-cellulose, hydroxyapatite, and preparative electrophoresis (Prep cell), of which the last was the most effective step in the purification of ASAT. The molecular mass was estimated to be 54,000 dalton by SDS-PAGE and 120,000 dalton by gel filtration chromatography. Preparative isoelectric focusing of purified ASAT resulted in one polypeptide band with a pI of 4.2, showing homogeneity and indicating that the enzyme is composed of two identical subunits. The enzyme was specific for L-aspartate as an amino donor ; the $K_{m}$ values were determined to be 2.7 mM for L-aspartate, 0.7 mM for 2-oxoglutarate, 12.8 mM for L-glutamate, and 0.15 mM for oxaloacetate. The enzyme was relatively heat-stable, having maximum activity at 55.deg.C, and it had a broad pH optimum ranging from 5.5 to 8.0. The activity of the purified enzyme was not inhibited by ammonium ions. This paper reports the first purification and characterization of the aspartate aminotransferase from a species of Streptomyces.s.

• Preventive Nutrition and Food Science
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• v.22 no.2
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• pp.118-123
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• 2017

This study was conducted to investigate the anti-adipogenic activity of esculetin (ECT) which is reported to be attributable to the modulation of antioxidant enzymes during adipogenesis. After six days of ECT treatment of 3T3-L1 cells, lipid accumulation was determined by Oil red O staining. The levels of glutathione (GSH) and reactive oxygen species (ROS), and the activities of antioxidant enzymes including glutathione reductase, glutathione peroxidase (GPx), and catalase were examined. In addition, the protein expression of glutamate-cysteine ligase catalytic subunit (GCLC) and heme oxygenase-1 (HO-1) was measured by Western blot. ECT significantly inhibited lipid accumulation by approximately 80% and ROS production in a concentration-dependent manner. GSH level and GPx activity were increased by ECT by approximately 1.3-fold and 1.7-fold compared to the control group, respectively. GCLC and HO-1 expression were elevated by ECT. These results showed that ECT treatments strongly inhibit adipogenesis, increase GSH level, and upregulate the expression of GCLC and HO-1, possibly by decreasing ROS production in 3T3-L1 cells during adipogenesis.