• Journal of the Korean Chemical Society
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• v.34 no.2
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• pp.203-210
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• 1990

As a possible biocompatible and biodegrable polymer skeleton for drug delivery system, block copolymers of L-lactic acid and L-glutamic acid with different composition were synthesized and characterized. Poly (L-lactide) was prepared by polymerization of L-lactide with zine oxide at $130^{\circ}C$ for 72 hrs. 3-Amino-l-propanol was introduced to poly (L-lactide) by an ester linkage in order to initiate polymerization. Polymerization of $\gamma-benzyl-L-glutamate-N-carboxyanhydride(\gamma-BLG-NCA)$ utiliizing the amino group of modified poly (L-lactide) as an initiator gave rise to the block copoly $(L-lactide-\gamma-benzyl-L-glutamate).$ The NMR study of resulting block copolymers showed that the composition of L-lactic acid and $\gamma-benzyl-L-glutamate$ in block copolymers was depended on the weight ratio of poly (L-lactide) and $\gamma-BLG-NCA.$ The thermal properties of the resulting block copolymers were determined by the differential scanning calorimetry and by the thermogravimetry.

• Proceedings of the Botanical Society of Korea Conference
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• 2001.04a
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• pp.11-11
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• 2001

• KSBB Journal
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• v.15 no.2
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• pp.195-200
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• 2000

Studies were made on the optimization of media to c비tivate Thraustochytrium aureum A TCC 34304 for the enhanc엉d p production of linoleic acid. The medium optimization was made with the artificial sea water medium. Yeast extract, sodium g glutamate, peptone and tryptone were considered as nitrogen source. The effect of $\infty$ncentration of nitrogen source as well a as initial glucose on the production of linoleic acid were investigated to optimize the media. The maximum yield of lipid was 0 0.302 mg/g cell mass when initial glucose $\infty$ncentration was 10 g/L and sodium glutamate was used as nitrogen source, a and the yield of linoleic acid to unit cell mass was also maximum to be 8 % in that case. The highest linoleic acid c concentration was obtained in the initial glucose concentration 30 g/L regardless of the kinds of nitrogen source and the | linoleic acid concentration was 0.208 g/L when peptone was supplemented to be 2 g/L.

• Archives of Pharmacal Research
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• v.20 no.1
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• pp.7-12
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• 1997

Glutamate uptake inhibitor, L-trans-pyrrolidine-2, 4-dicarboxylate (PDC, $20{\mu}M$) elevated basal and N-methyl-D-aspartate (NMDA, $100{\mu}M$)-induced extracellular glutamate accumulation, while it did not augment kainate $100{\mu}M$-induced glutamate accumulation in cultured cerebellar granule neurons. However, pretreatment with PDC for 1 h significantly reduced NMDA-induced glutamate accumulation, but did not affect kainate-induced response. Pretreatment with glutamate $(5{\mu}M)$ for 1 h also reduced NMDA-induced glutamate accumulation, but did not kainate-induced response. Upon a brief application (3-10 min), PDC did neither induce elevation of intracellular calcium concentration $([Ca^{2+}]_i)$ nor modulate NMDA-indLiced $[Ca^{2+}]_1$ elevation. Pretreatment with PDC for 1 h reduced NMDA-induced $[Ca^{2+}]_1$ elevation, but it did not reduce kainate-induced $[Ca^{2+}]_1$ elevation. These results suggest that glutamate concentration in synaptic clefts of neurana cells is increased by prolonged exposure (1 h) of the cells to PDC, and the accumulated glutamate subsequently induces selective desensitization of NMDA receptor.

• Journal of Microbiology and Biotechnology
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• v.27 no.9
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• pp.1664-1669
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• 2017

Gamma-aminobutyric acid is a precursor of nylon-4, which is a promising heat-resistant biopolymer. GABA can be produced from the decarboxylation of glutamate by glutamate decarboxylase. In this study, a synthetic scaffold complex strategy was employed involving the Neurospora crassa glutamate decarboxylase (GadB) and Escherichia coli GABA antiporter (GadC) to improve GABA production. To construct the complex, the SH3 domain was attached to the N. crassa GadB, and the SH3 ligand was attached to the N-terminus, middle, and C-terminus of E. coli GadC. In the C-terminus model, 5.8 g/l of GABA concentration was obtained from 10 g/l glutamate. When a competing pathway engineered strain was used, the final GABA concentration was further increased to 5.94 g/l, which corresponds to 97.5% of GABA yield. With the introduction of the scaffold complex, the GABA productivity increased by 2.9 folds during the initial culture period.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.345-345
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• 2006

It is well known that poly(glutamate)s with long n-alkyl side chains form thermotropic liquid crystalline state by melting of the side-chain crystallites and also poly(glutamate)s such as poly(${\gamma}-benzyl\;L-glutamate$ )(PBLG), poly(${\gamma}-n-alkyl\;L-glutamate$), etc. in solvent form the isotropic, biphasic and liquid crystalline phases which contains cholesteric and columnar liquid crystalline forms depending on the polypeptide concentration. Although there is no diffusion study for PBLG in liquid crystalline state, because it is difficult to observed $^{1}H$ spectrum of PBLG in liquid crystalline state for its very short $^{1}H\;T_{2}$. In this study, the diffusional behavior of rodlike PBLG in concentrated solution is successfully elucidated as studied by the field-gradient $^{1}H$ NMR methods.

• Korean Journal of Pharmacognosy
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• v.44 no.4
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• pp.379-383
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• 2013

Portulaca oleracea L. is known to have many biological benefits such as anti-oxidant, anti-inflammatory, anti-allergic and anti-tumor. The objective of this study is to explore the neuroprotective effect of P. oleracea L. against glutamate-induced oxidative stress in mouse hippocampal HT22 cells. P. oleracea L. 70% ethanol extract and solvent fractions have the potent neroprotective effects on glutamate-induced nerotoxicity by induced the expression of heme oxygenase (HO)-1 in HT22 cells. Especially, ethyl acetate fraction showed higher protective effect. In HT22 cell, P. oleracea L. treatment with ERK inhibitor (PD98059) and c-JUN N-terminal kinase (JNK) inhibitor (SP600125) reduced P. oleracea L. ethyl acetate fraction induced HO-1 expression and P. oleracea L. ethyl acetate fraction also increased ERK and JNK phosphorylation. Furthermore, we found that treatment of P. oleracea L. caused the nuclear accumulation of Nrf2. In conclusion, the ethyl acetate fraction of 70% ethanol extract of P. oleracea L. significantly protect glutamate-induced oxidative damage by induction of HO-1 via Nrf2, ERK and JNK pathway in mouse hippocampal HT22. Taken together these finding suggest that P. oleracea L. ethyl acetate fraction is good source for taking active compounds and may be a potential therapeutic agent for brain disorder that induced by oxidative stress and neuronal damage.

• Journal of Ginseng Research
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• v.24 no.3
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• pp.138-142
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• 2000

Effects of ginsenosides (Rb$_1$, Rb$_2$, Rc, Re, Rg$_1$, Rf) on L-glutamate (glutamate)-induced swelling of cultured astrocytes from rat brain cerebral cortex were studied. Following the exposure to 0.5mM glutamate for 1 hr, the intracellular water space (as measured by [$^3$H]O-methyl-D-glucose uptake) of astrocytes increased by about two-fold. Simultaneous addition of ginsenosides Rb$_2$ and Rc with glutamate reduced the astrocytic swelling in a dose-dependent manner. These ginsenosides at 0.5 mg/ml did not affect the viability of astrocytes for up to 24 hr which was determined by a colorimetric assay (MTT assay) for cellular growth and survival. These ginsenosides at 0.3 mg/ml inhibited the increase of intracellular Ca$\^$2+/ concentration ([Ca$\^$2+/]$\_$i/) induced by glutamate. These data suggest ginsenosides Rb$_2$ and Rc prevent the cell swelling of astrocytes induced by glutamate, maybe via inhibition of Ca$\^$2+/ influx.

• Journal of Pharmaceutical Investigation
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• v.22 no.3
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• pp.237-240
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• 1992

A series of biodegradable block copolymers consisting of $poly({\gamma}-benzyl\;L-glutamate)$ (PBLG) and poly(ethylene oxide) (PEO)-lactoselactone were prepared by polymerization of PEO-lactoselactone and ${\gamma}-benzyl$ L-glutamate-N-carboxyanhydride and characterized by IR and NMR. From circular dichroism measurements, it was found that the polymers exist in the ${\alpha}-helical$ conformation. Block copolymer microspheres were prepared by solvent-extraction-precipitation method for their primary evaluation for medical and biological applications.

• YAKHAK HOEJI
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• v.35 no.5
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• pp.384-388
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• 1991

To explore the effect of monosodium-L-glutamate(MSG) on CCI$_{4}$-damaged liver in Wister male rat, 5% MSG solution as drink water were administered after S.C. injection of 0.1 mg/kg CC1$_{4}$ twice a week for 4 weeks. After last administration of MSG, heptic glutathione(GSH) dependent system was assayed. It showed that MSG increased significanly hepatic glutathione(GSH) and glutathione peroxidase(GSH$_{px}$), but decreased glutathione-S-transferase(GST) acivity in normal rats. MSG increased significantly the GSH$_{px}$ and GST activities in rats with CCI$_{4}$-induced liver damage. These results indicate that decrease of GSH dependent systems in CC1$_{4}$ liver injury might be partially elevated by coadministration of MSG.