• Biomolecules & Therapeutics
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• v.8 no.4
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• pp.299-304
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• 2000

The modulation of cytochrome P450(P450) activities and glutathione S-transferase (GST) was investigated after i.p. administration of glucose-diethyldithiocarbamate (Glu-DDTC) to rats. P450 1 A2 and 2El activities were inhibited by 60% 4 hr after the administration of 200 mg Glu-DDTC/kg and those activities were recovered to original levels 24 hr after dosing. In contrast, GST activities were enhanced up to 24 hr after dosing. These results seem to be due to the bifunctional activity of Glu-DDTC. Glu-DDTC acts as an inhibitor of P450 enzymes as well as inducer of GST enzyme. Glu-DDTC inhibited PNP hydroxylation (P450 2El) and ethoxycoumarin O-deethylation (P450 1A2) in a dose-dependent manner up to 200 mg/kg wherease it did not affect testosterone 6$\beta$-hydroxylation (P450 3A) and pentoxyresorufin O-dealkylation (P450 2B) activities. Induction of GST activity toward 1-chloro-2,4-dinitrobenzene (CDNB) and 1,2-dichloro-4-nitrobenzenen (DCNB) was dependent on the dose of Glu-DDTC and no species difference in the GST induction was seen between rat and mouse. Amoung GST subunits, Ya, Yb1 and partially Yb2 were induced by Glu-DDTC as conjugated by western blotting. The levels Yp, Yk and Yc subunits were not affected by Glu-DDTC treatment. Therefore the enhanced activity of GST toward CDNB and DCNB might be due to the induction of Ya, Ybl and partially Yb2 subunits. In conclusion, Glu-DDTC selectively inhibited P45O 1A2 and P450 2El activities whereas it enhanced Ya, Ybl subunits and partially Yb2 subunits of GST and the antimutagenic activity of this compound might be attributed from the modulation of these enzyme activities in animals.

• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1438-1439
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• 2006

$Ge_{2}Sb_{2}Te_5$(GST) thin film at present is a promising candidate for a phase change random access memory (PCRAM) based on the difference in resistivity between the crystalline and amorphous phase. PCRAM is an easy to manufacture, low cost storage technology with a high storage density. Therefore today several major chip in manufacturers are investigating this data storage technique. Recently, A. Pirovano et al. showed that PCRAM can be safely scaled down to the 65 nm technology node. G. T Jeonget al. suggested that physical limit of PRAM scaling will be around 10 nm node. Etching process of GST thin ra films below 100 nm range becomes more challenging. However, not much information is available in this area. In this work, we report on a parametric study of ICP etching of GST thin films in $Cl_2$/Ar chemistry. The etching characteristics of $Ge_{2}Sb_{2}Te_5$ thin films were investigated using an inductively coupled plasma (ICP) of $Cl_2$/Ar gas mixture. The etch rate of the GST films increased with increasing $Cl_2$ flow rate, source and bias powers, and pressure. The selectivity of GST over the $SiO_2$ films was higher than 10:1. X-ray photoelectron spectroscopy(XPS) was performed to examine the chemical species present in the etched surface of GST thin films. XPS results showed that the etch rate-determining element among the Ge, Sb, and Te was Te in the $Cl_2$/Ar plasma.

• Korean Journal of Optics and Photonics
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• v.14 no.1
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• pp.23-32
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• 2003

The spectroe-ellipsometric constant $\Delta$, Ψ and the ellipsometric growth curves at the wavelength of 632.8 nm are collected. These are critically examined to find out the optimum growth condition of phase change $Ge_2Sb_2Te_5(GST)$ thin films as an optical recording medium. GST films are prepared using DC magnetron sputtering technique, under the selected experimental conditions of Ar gas pressure (5 mTorr, 7 mTorr and 10 mTorr), DC power of sputtering gun (15 W, 30 W and 45 W), and substrate temperature (from room temperature to 18$0^{\circ}C$). Based on the three film model, the density distribution of deposited GST films are obtained versus Ar gas pressure and DC power by analyzing spectro-ellipsometric data. The calculated evolution curves at the wavelength of 632.8 nm, are fit into the in situ observed ones to get information about the evolution of density distribution during film growth. The density distribution showed different evolution curves depending on deposition conditions. The GST films fabricated at DC power of 30 W or 45 W, and at Ar gas pressure of 7 mTorr turned out to be the most homogeneous one out of those prepared at room temperature, even though the maximum density difference between the dense region and the dilute region of the GST film was still significant (~50%). Finally, in order to find the optimum growth condition of homogeneous GST thin films, the substrate temperature is varied while Ar gas pressure is fixed at 7 mTorr and DC power at 30 W and 45 W respectively. A monotonic decrease of void fraction except for a slight increase at 18$0^{\circ}C$ is observed as the substrate temperature increases. Decrease of void fraction indicates an increase of film density and hence an improvement of film homogeneity. The optimum condition of the most homogeneous GST film growth turned out to be 7 mTorr of Ar gas pressure, 15$0^{\circ}C$ of substrate temperature. and 45 W of DC power. The microscopic images obtained using scanning electron microscope, of the samples prepared at the optimum growth condition, confirmed this conclusion. It is believed that the fabrication of homogeneous GST films will be quite beneficial to provide a reliable optical recording medium compatible with repeated write/erase cycles.

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.667-671
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• 2003

The total phenolic and flavonoid contents of Lentinus edodes extracts were determinated by spectrophotometrical .method, and antihepatotoxic activity was detected on glutathione S-Transferases(GST). The total phenolic contents was highest water extract than solvent(ethanol, methanol) extracts, but flavonoid content was appear on opposite. GST activity was the highest appears in water extract. This fact verified of anticancer effect indirectly of Lentinus edodes.

• Transactions on Electrical and Electronic Materials
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• v.15 no.1
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• pp.37-40
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• 2014

A novel memory is reported, in which $Ge_2Sb_2Te_5$ (GST) has been used as a floating gate. The threshold voltage was shifted due to the phase transition of the GST layer, and the hysteretic behavior is opposite to that arising from charge trapping. Finite Element Modeling (FEM) was adapted, and a new simulation program was developed using c-interpreter, in order to analyze the small shift of threshold voltage. The results show that GST undergoes a partial phase transformation during the process of RESET or SET operation. A large $V_{TH}$ shift was observed when the thickness of the GST layer was scaled down from 50 nm to 25 nm. The novel 1 transistor PCM (1TPCM) can achieve a faster write time, maintaining a smaller cell size.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.442-444
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• 2006

On long time scale and over large areas ground surface temperatures (GSTs) track surface air temperatures (SATs). Additionally, GST changes penetrate into the subsurface and are recorded as transient temperature perturbation to the background thermal filed. Therefore, climate change can be reconstructed from borehole temperature measurements We present GST hi story reconstructed from temperature measurements in a borehole at Pocheon The result shows that GST cold period in the late 19th century and then increased by about 2K to 1990. GST history matches well with surface air temperatures measured from 1907 to 2001 at the Seoul Meteorological Station and GST history reconstructed from temperature measurements in three boreholes at Ulsan.

• Journal of Microbiology
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• v.42 no.4
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• pp.353-356
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• 2004

In a previous study, a gst gene was isolated from the fission yeast Schizosaccharomyces pombe. This gene was dubbed gstI, and was characterized using the gstI -lacZ fusion plasmid pYSH2000. In this work, four additional fusion plasmids, pYSHSDl, pYSHSD2, pYSHSD3 and pYSHSD4, were constructed, in order to carry (respectively) 770, 551, 358 and 151 bp upstream regions from the translational initiation point. The sequence responsible for induction by aluminum, mercury and hydrogen peroxide was located in the range between -1,088 and -770 bp upstream of the S. pombe gstI gene. The same region was identified to contain the nucleotide sequence responsible for regulation by Papl, and has one puta­tive Papl binding site, TTACGTAT, located in the range between $-954\~-947$ bp upstream of the gstI gene. Negatively acting sequences are located between -1,088 and -151 bp. These findings imply that the Papl protein is involved in basal and inducible transcription of the gstI gene in the fission yeast S. pombe.

• International Journal of Industrial Entomology and Biomaterials
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• v.18 no.1
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• pp.28-32
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• 2009

We describe here the cloning and characterization of a cDNA encoding the glutathione S-transferase (GST) from the bumblebee Bombus ignitus. The Delta-class B. ignitus GST (BiGSTD) gene spans 1668 bp and consists of four introns and five exons that encode 216 amino acid residues with a calculated molecular weight of approximately 24561 Da and a pI of 8.03. The N-terminal domain of BiGSTD has a conserved Ser residue, as well as conserved Lys, Pro, Glu, Ser and Tyr residues that are involved in the GSH-binding site of GST. The BiGSTD showed 60% protein sequence identity to the Bombyx mori GSTT1, 58% to Musca domestica GST, 57% to Drosophila melanogaster GST, and 55% to Anopheles gambiae GST1. BiGSTD was close to the insect-specific Delta class of GSTs in a phylogenetic tree. Northern blot analysis showed that BiGSTD is highly expressed in the fat body and midgut, and less so in the muscles of B. ignitus worker bees.

• BMB Reports
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• v.31 no.3
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• pp.287-295
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• 1998

Acetolactate synthase (ALS) is the first common enzyme in the biosynthesis of L-Ieucine, L-isoleucine, and L-valine. The sulfonylurea-resistant ALS gene from Nicotiana tabacum was cloned into the bacterial expression vector pGEX-2T. The resulting recombinant plasmid pGEX-ALS3 was used to transform Escherichia coli strain XL1-Blue, and the mutant tobacco ALS (mALS) was expressed in the bacteria as a protein fused with glutathione S-transferase (GST). The fusion product GST-mALS was purified in a single step on a glutathione-Sepharose column. ALS activities of 0.9-2.5 ${\mu}mol/min/mg$ protein were observed in the GST-mALS, and the Km values for pyruvate, FAD, and TPP were 10.8-24.1, $(1.9-8.9){\times}10^{-3}$, and 0.14-0.38 mM, respectively. The purified GST-mALS was resistant to both the sulfonylurea and the triazolopyrimidine herbicides, and lost its sensitivity to end products, L-valine and L-leucine. For comparision, the tobacco wild-type recombinant ALS fused with GST, GST-wALS, was also characterized with respect to its pyruvate and cofactor bindings. These results suggest that the purified mutant recombinant tobacco ALS was functionally active, that the mutations resulting in herbicide resistance has affected pyruvate and cofactor bindings," and that the two classes of herbicides interact at a common site on the plant ALS.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.12
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• pp.7375-7379
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• 2013

The main aim of this study was to investigate the roles of GST-${\pi}$ and $pol{\beta}$ genes in the chemoresistance of esophageal carcinoma cells. Eukaryotic expression vectors containing each gene were constructed and transfected into EC9706 cells, and the biological effects of the two genes assessed based on a resistance index. We additionally investigated the in vitro and in vivo anti-resistance effects of GST-${\pi}$ and $pol{\beta}$ genes using recombinant lentiviruses carrying siRNAs against the two genes. Our results showed that upregulation of GST-${\pi}$ and $pol{\beta}$ genes suppresses chemosensitivity of esophageal carcinoma cells to cisplatin, while downregulation of these two genes with RNAi technology reverses this chemoresistance. Multi-site injection of recombinant lentivirus targeting the GST-${\pi}$ gene into transplanted cDDP tumors effectively reversed their chemoresistant phenotype. However, the same treatment against the $pol{\beta}$ gene did not lead to significant efficacy against chemoresistance.