• Journal of Acupuncture Research
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• v.17 no.3
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• pp.208-218
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• 2000

This study was undertaken to determine if Salviae Radix (SR) exerts protective effect against oxidant-induced inhibition of phosphate uptake in renal proximal tubular cells. Membrane transport function and cell death were evaluated by measuring phosphate uptake and trypan blue exclusion, respectively, in opossum kidney (OK) cells, an established proximal tubular cell line. $H_2O_2$ was used as a model oxidant. $H_2O_2$ inhibited the phosphate uptake in a dose-dependent manner over the concentration range of 0.1-0.5 mM. Similar fashion was observed in cell death. However, the phosphate uptake was more vulnerable to $H_2O_2$ than cell death, suggesting that $H_2O_2$-induced inhibition of phosphate uptake is not totally attributed to cell death. Decreasedphosphate uptake was associated with ATP depletion and inhibition of $Na^+$-pump activity as determined by direct inhibition of $N^+-K^+$-ATPase activity. When cells were treated with $H_2O_2$ in the presence of 0.05% SR, the inhibition of phosphate uptake and cell death induced by $H_2O_2$ was significantly attenuated. SR restored ATP depletion and decreased $Na^+-K^+$-ATPase activity, and this is likely responsible for the protective effect of SR on decreased phosphate uptake. The protective effect of SR was similar to the $H_2O_2$ scavenger catalase. SR reacts directly with $H_2O_2$ to reduce the effective concentration of the oxidant. The iron chelator deferoxamine prevented the inhibition of phosphate uptake and cell death induced by $H_2O_2$, suggesting that $H_2O_2$-induced cell injury is resulted from an iron-dependent mechanism. These results indicate that SR exerts the protective effect against $H_2O_2$-induced inhibition of phosphate uptake by reacting directly with $H_2O_2$ like the $H_2O_2$scavenger enzyme catalase, in OK cells. However, the underlying mechanism remains to be explored.

• Journal of Microbiology
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• v.35 no.4
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• pp.315-322
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• 1997

The effects of a polyamine, spermine, on the differentiation of Naegleria gruberi amebas into flagellates were tested. Addition of spermine at early stages of differentiation (until 40 min after the initiation of differentiation) completely inhibited the differentiation. To understand the inhibition mechanism, we examined the effect of spermine treatment on the transcription and translation of differentiation-specific genes during differentiation. Addition of spermine at early stages did not inhibit the accumulation of two differentiation-specific mRNAs, ${\alpha}$-tubulin and Class I mRNA, significantly, but rather prevented the rapid degradation of the mRNAs in later overall protein synthesis partially and gradually. However, translation of the ${\alpha}$-tubulin mRNA was completely inhibited. These data suggest that the inhibition of differentiation of N. gruberi by spermine treatment did not result from the inhibition of transcription of differentiation-specific genes but from the specific inhibition of translation of the mRNAs during the differentiation.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.29 no.2
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• pp.86-94
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• 2003

It has been known that transglutaminase C (TGase C, TGase II) is directly participated in the DNA organization of chromosome, and affects the cellular processes such as proliferation, differentiation, and apoptosis of cells, but still not known what mechanism is working on. In this study, the cytogenetic and the immunohistochemical methods were used to observe the TGase C expression in the nuclear chromosome of the proliferating cells, especially in mitotic stage. The human gastric adenocarcinoma (SNU-1) cell line was used for immunohistochemistry and antisense inhibition study in vitro. The present study was also aimed to disclose the efficiency of antisense inhibition by using antisense oligonucleotide DNA labeled with fluorescence, and found that anti-TGase C probe was diffusely infiltrated into the cytoplasm and the nucleus of the cell. By the antisense inhibition the nuclei of SNU-1 cells became rough nuclear shape, as they were greatly reduced in TGase C immunoreactivity both for the normal and apoptotic SNU-1 cells. However, it is clearly presumed that the TGase C directly interacts with the chromosome of SNU-1 cells and it may play an important role in the division and organization of the chromosome during the mitotic stage.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.11a
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• pp.27-28
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• 2021

The search for new corrosion inhibitors for different corrosive mediums is a never-ending task. In the present work, the corrosion inhibition behavior and adsorption mechanism of two novel synthetic thiazolidinedione derivatives noted MTZD and ATZD in 3.5 wt.% NaCl solution on copper were investigated. Electrochemical, scanning electron microscope (SEM), atomic force microscopy (AFM) techniques were used along with first-principles DFT calculations. At maximum inhibitor concentration i.e., 300 ppm corrosion inhibition efficiency reached maximum up to 90% and 96% for MTZD and ATZD, respectively, and thereby followed the order of ATZD > MTZD. The inhibition efficiency increased up to 24 h of immersion, and then decreased after 48h immersion. The potentiodynamic curves suggested that the inhibition action of tested compounds is a mixed type of inhibitor. The first-principles DFT calculations suggested that compounds under investigation formed covalent bonds with Cu(111) surface via reactive sites. SEM and AFM results confirmed the formation of protective barrier that prevent corrosion attack.

• BMB Reports
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• v.29 no.3
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• pp.210-214
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• 1996

The pH dependence of the kinetic parameters of mutant O-acetylserine sulfhydrylase (OASS) from Salmonella typhimurium LT-2 has been determined in order to obtain information on the chemical mechanism. The initial velocity pattern obtained by varying the concentrations of OAS at several fixed concentrations of TNB, shows an intersection on the left of the ordinate at pH 7.0, indicating that the kinetic mechanism is a sequential mechanism in which substrate inhibition by OAS is observed while the wild type enzyme showed a ping pong mechanism. The values of $V/E_t$, $V/K_{OAS}E_{t}$ and $V/K_{TNB}E_{t}$ decreased by about 68%, 14% and 16% as compared with the wild type enzyme. The $V/K_{OAS}E_{t}$ is a pK of 6.5 on the acid side of the pH profile, and the $V/K_{TNB}$ is pH independent. As compared with the wild type enzyme, the pKs in the V/K profiles are shifted, reflecting that binding of the cofactor in free E:OAS is less asymmetric.

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.674-675
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• 2003

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2000.04a
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• pp.23-24
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• 2000

• Archives of Pharmacal Research
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• v.7 no.1
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• pp.65-68
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• 1984

Mechanism of the monoamine oxidase inhibition by tranylcypromine was studied in relation to its metabolism to reactive apecies. A metabolic study performed to collect general biotransformation pathway in rats provided GC/MS evidence for the detection of two new metabolites, N-acetyl and hydroxylated N-acetyltranylacypromine.

• BMB Reports
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• v.33 no.1
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• pp.1-36
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• 2000

Acetohydroxyacid synthase (EC 4.1.3.18) catalyses the first reaction in the pathway for synthesis of the branched-chain amino acids. The enzyme is inhibited by several commercial herbicides and has been subjected to detailed study over the last 20 to 30 years. Here we review the progress that has been made in understanding its structure, regulation, mechanism, and inhibition.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.131.1-131.1
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• 2003

Phytoestrogens are naturally occurring compounds derived from plants. Structurally, some phytoestrogens resemble endogenous estrogen of humans and animals. Phytoestrogens exhibit estrogen agonist/antagonist properties and have many biological effects such as prevention of hormone-dependent breast cancer, anti-oxidative activity, inhibition of tyrosine kinase activities and inhibition of angiogenesis. In this study we investigated whether biochanin A, a phytoestrogen, and its metabolites such genistein, p-ethylphenol and phenolic aic affect IL-4 production in EL-4 thymoma cell-line and primary lymph node cells. (omitted)