• Korean Journal of Microbiology
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• v.24 no.2
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• pp.113-118
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• 1986

Optimum temperature and pH of glutamine synthetase activity (E.C. 3.6.1.2.) of R. sphaeroides D-230 was $35^{\circ}C$ and 6.8, respectively. The adenylated state of GS in R. sphaeroides D-230 was stabilized by addition of 0.2mg/ml of cethyltrimethylammoniumbromide. Valine, histidine, proline, isoleucine, and lysine were good nitrogen source for the growth of R. sphaeroides D-230. The growth of R. sphaeroides D-230 in $N_2,\;NaNO_3\;or\;NH_4Cl$ as sole nitrogen source was lower than in any otherculture conditions. GS activity was inhibited, more or less, by various amino acid. THe relative inhibition rate of the enzyme by added 7mM arginine, $NH_4Cl,\;N_2,\;and\;NaNO_3$ was 63.8%, 26.79%, 6.24%, and 10.64%, drespectively. THe hydrogen evolution of R. sphaeroides D-230 grown in N-limited media was inhibited by 0.1mM MSX, irreversible GS inhibitor. GS activity was completely inhibited by 1.0mM MSX but ammonia released maximally at the same concentration of MSX. Ammonia release by added MSX was increased up to 1.0mM MS, but decreased above 1.0mM MSX. It is probably due to inhibition of nitrogenase actixity by MSX. Nitrogenase activity was not inhibited at low concentration of MSX. These results suggests that the inhibition of nitrogenase activity by ammonia is mediated by products of ammonia assimilation rather than by ammonia itself.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.11
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• pp.4769-4775
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• 2015

Background: Hepatocellular carcinoma (HCC) is the fifth most prevalent cancer and thirdly leading cause of cancer-related death worldwide. The estimated risk of hepatocellular carcinoma is 15 to 20 times as high among persons infected with HCV as it is among those who are not infected, with most of the excess risk limited to those with advanced hepatic fibrosis or cirrhosis. Glypican3 (GPC3) plays a key role in relation to signaling with growth factors, regulating the proliferative activity of cancer cells. Glutamine synthetase (GS) catalyzes the synthesis of glutamine from glutamate and ammonia in the mammalian liver. GS was suggested as a specific marker for tracing cell lineage relationships during hepatocarcinogenesis. In normal liver, GS expression is seen in pericentral hepatocytes, but not by midzonal or periportal hepatocytes. In HCC, strong and diffuse GS expression in seen in tumor cells. Results: Glypican3 immunopositvity was highly specific and sensitive indicator for hepatocellular carcinoma as well as glutamine synthetase which was found to be a sensitive and specific indicator for development of hepatocellular carcinoma when compared to cirrhosis, liver cell dyspalsia and metastatic carcinomas. Statistical analysis revealed a significant association between GPC3 and GS with tumor size (P=0.003, p=0.006, respectively). Diffuse staining significantly associated with large tumor size while, focal and mixed staining was detected more with small tumor size. Studying the relation with tumor grade also revealed significant association between diffuse GPC3 and GS staining with high tumor grade. Diffuse staining was detected in 91.7% and 100% respectively of poorly differentiated specimens and only in 33.3% and 22.2% of well differentiated specimens. Conclusions: While using GPC3 and GS to screen for premalignant hepatic lesions remains controversial, our data suggest that GPC3 and GS may be a reliable diagnostic immunomarkers to distinguish HCC from benign hepatocellular lesions. However, negative immunostaining should not exclude the diagnosis of HCC.

• 한국생물공학회:학술대회논문집
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• 2002.04a
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• pp.309-312
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• 2002

Exogenous glutamine synthetase (GS) was used efficiently as a selectable marker to identify successful transfectants for the production of erythropoietin (EPO) in Chines hamster ovary (CHO-K1) cells in the absence of glutamine. Inclusion of methionine sulphoximine (MSX), an inhibitor of glutamine synthetase, enabled further selection of clones with relatively high levels of transfected glutamine synthetase and EPO genes which were coupled together. In this study, a new cell line was established by using GS system and enhancement of EPO production by zinc ion was evaluated using the transfected CHO-K1 cell line under normal condition. It was found that EPO production from CHO-K1 cells was enhanced 40% when the optimal amount of zinc ion was added.

• Korean Journal of Microbiology
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• v.30 no.6
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• pp.564-569
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• 1992

A green sulfur bacterium, Chlorobium limicola f. thiosulfatophilum NCIB 8327, was grown in modified Pfennig's medium including glu1amate as a nitrogen source. Glutamine synthetase was isolated through a series of ultracentrifugation. DEAE-Sepharose CL-6B ion exchange chromatography. Sephacryl S-300 gel permeation chromatography, and preparative HPLC. The recovery and purification fold of the enzyme were 2% and 46.3. respectively. The isolated enzyme was homogeneous on UV-Visible spectrum and polyacrylamide gel electrophoretogram. The relative molecular mass of the native enzyme was estimated to be 280,000 by gel permeation chromatography. The enzyme consisted of ten subunits with relative similar molecular mass. 30.000. which was estimated by SDS-polyacrylamide gel electrophoresis. The optimal temperature and pH of the enzyme were $30^{\circ}C$ and 7.0. Km values were 27.9 mM for L-glutamine and 0.92 mM for hydroxylamine-HCr. The enzyme activity was inhibited by alanine. glycine. and tryptophan considerably, but was not affected by asparagine, lysine. leucine. and valine.

• Proceedings of the Korean Society of Crop Science Conference
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• 1987.06a
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• pp.54-55
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• 1987

• Proceedings of the Botanical Society of Korea Conference
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• 1996.06a
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• pp.50-63
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• 1996

Nitrogen (N) is an important regulator of the expression of genes involved in carbon and N assimilation pathways in plants by selectively altering the levels of proteins and/or mRNAs. These in C4 plants include genes for such as phosphoenolpyruvate carboxylase, carbonic anhydrase, and pyruvate-Pi dikinase. The C4 genes are regulated in mesophyll cells by N availability both transcriptionally and posttranscriptionally through cytokinins and glutamine as signals. The level of both the signals is up-regulated by N availability: cytokinins in roots and glutamine in leaves. The level of glutamine is controlled by the differential expression by N of glutamine synthetase and ferrdoxin-dependent glutamate synthase genes which locate in the mesophyll cells of C4 plants. The results is discussed as molecular mechanism for the greater N use efficiency of the plants as well as N partitioning is the photosynthetic cells.

• The Journal of Natural Sciences
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• v.14 no.2
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• pp.55-65
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• 2004

A thiol-specific antioxidant(TSA) protein was purified from Earthworm, Lumbricus terrestris by DEAE-Cellulose, Phenl sepharose, Sephacryl S-200 gel filtration and HPLC S-300 Column Chromatography. This protein showed a thiol-specific antioxidant activity against inactivation of glutamine synthetase by a metal-catalysed oxidation system capable of generation reaction oxygen species. The molecular mass of the protein was determinated to be 51-kDa by SDS-polyacrylamide gel electrophores. Taken together, the purified TSA protein could be a new member of TSA family.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.228.2-229
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• 2002

Methylmercury (MeHg). a potent neurotoxicant. produces neuronal death that may be partially mediated by glutamate. Glutamine synthetase (GS), a glial-specific enzyme. catalyzes the synthesis of glutamine from glutamate and ammonia and is associated with ischemic injury and neurological diseases. Objectives of this experiment are to investigate whether in vivo and in vitro MeHg exposure have adverse effects on GS and whether duration of exposure to MeHg and glutamate co-treatment playa role in MeHg-induced toxicity. (omitted)

• Journal of Life Science
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• v.10 no.5
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• pp.533-541
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• 2000

Compared to mammal including human, many bioreactive genes that regulate various biological events has not been cloned and characterized yet in fishes, especially shark, Scyliorhinus torazame. In orther to isolate genes that regulate physiological processes in cartilaginors fishes, we performed reverse transcription-polymerase chain reaction (RT-PCR) using the RNA of cartilage tissues of Scyliofhinus torazame. The cloned partial genes were 86%, 80%, 73%, 84%, 75%, 79% identical to $\alpha$- actin, 90-kDa heat-shock protein, methyle-neterahydrofolate dehydrogenase-methenyltertrahydrofolate cyclohudrolase-formyltetrahydrofolate synthetase, ubiquitin, glutamine synthetase and connective tissue growth factor genes of human, respectively. They also have similar nucleotide sequence homologues with those of another species. These partial bioreactive genes elucidated in this study may support to studies of phylogenetic analysis based on evolutionary relationships between shark and other species.

• Korean Journal of Weed Science
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• v.11 no.3
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• pp.195-204
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• 1991

This study was conducted to determine physiological responses rice cultivars to glufosinate-ammonium. Changes of total protein content, protein population, glutamine synthetase activity, accumulated ammonia content and free amino acid composition were examined in both tolerant and susceptible rice cultivars. Tamjinbyeo and Fukei 126 showed relatively tolerant response to glufosinate-ammonium while Namyeongbyeo, Palgongbyeo and Youngdugbyeo were susceptible to it. Total protein content of two tolerant cultivars was 93.2 of the untreated control in average but three susceptible cultivars showed 76.5 of the untreated control in average, showing 16.7 difference. Protein profiles of the tolerant cultivars seemed to be not affected by glufosinate-ammonium treatment. However, in susceptible cultivar like Namyeongbyeo, 10ppm of glufosinate-ammonium application resulted in decrease of band density or disapperance of spot density in near 20kD and in between 45kD and 66kD on 2D-PAGE. Glutamine synthetase activity in susceptible cultivars was markedly inhibited by glufosinate-ammonium treatment, accompanying remarkable increase of ammonia content by three times greater than tolerant cultivars, and markedly increase of glutamic acid, showing 430% of the untreated control.