• Proceedings of the PSK Conference
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• 2003.10b
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• pp.167.1-167.1
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• 2003

Here we show that panaxadiol, a ginseng saponin with a dammarane skeleton, induces acute apoptotic cell death in human hepatoma SK-HEP-1 cells as evidenced by analysis of DNA fragmentation, caspase activation, and changes in cell morphology. The kinetic study showed that panaxadiol-induced apoptosis is associated with depolarization of mitochondrial membrane potential and cytochrome c release. Sequential activations of caspases-depolarization of mitochondrial membrane potential and cytochrome c release. Sequential activations of caspases-9, and -3, or -7, but not of caspase 8 coincide well in a time dependent manner with mitochondrial membrane depolarization and cytochrome c release from mitochondria during apoptosis of SK-HEP-1 cells induced by treatment with panaxadiol. (omitted)

• Microbiology and Biotechnology Letters
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• v.50 no.3
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• pp.387-394
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• 2022

Verotoxin-1 (VT-1) or Shiga-like toxin 1 (Stx-1) is produced by enterohemorrhagic Escherichia coli (EHEC) and is an AB5 holotoxin with a strong inhibitor of protein synthesis. VT-1 is a type 2 ribosome-inactivating protein (RIP) that has been shown to have cytotoxic and anticancer potential by inducing necrosis, apoptosis, and cell cycle arrest, making it a promising antitumor candidate. Here, we tested the cytotoxicity of VT-1 on CaCo2 and NCM425 cell lines and the results showed that VT-1 was more potent on CaCo2. Morphological changes were also evaluated on the cellular level and the results showed that VT-1 caused a decrease in viable cell count, altered cell membrane permeability, and an increase in total nuclear intensity. On the other hand, VT-1 displayed a lesser impact on mitochondrial membrane potential (MMP) and cytochrome c release. On the expression of caspases 3 and 9, VT-1 exhibited an insignificant effect on both which alongside the mitochondrial membrane potential (MMP) and cytochrome c results, might indicate that CaCo2 suffered from the necrosis process as a mechanism of cell death after exposure to VT-1.

• Journal of Plant Biology
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• v.36 no.4
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• pp.383-389
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• 1993

The effects of light and $CO_2$ on the electrophysiological characteristics of guard cells in the intact leaf and in the detached epidermis have been investigated. Guard cells in intact leaves showed the membrane hyperpolarization in response to light. The biggest induced change of the membrane potential difference (PD) in the guard cells of the intact leaf was 13 m V by light and 42 mV by $CO_2$ in Commelina communis. Similar results were obtained with Tradescantia virginiana. However, there were no changes of membrane PD in detached epidermis. In order to determine the influence of the mesophyll on the changes of membrane PD, infiltration of the mesophyll cells with photosynthetic inhibitors was performed. In CCCP infiltrated leaf discs the guard cell membrane was depolarized slightly by red-light and hyperpolarized by $CO_2$, but in leaf discs infiltrated with DCCD and DCMU the guard cell membrane was hyperpolrized by both red-light and $CO_2$ as the control leaf discs. In azide infiltrated leaf discs the guard cell membrane showed no response to light and there was a much reduced membrane hyperpolarization by $CO_2$ compared to other responses. It was likely that azide caused leaf damage and the activity of cell metabolism was decreased greatly, resulting in small membrane PD changes by $CO_2$ and no changes by redlight. Therefore, it can be suggested that red light was sensed by the mesophyll and the light induced guard cell membrane hyperpolarization was related to energy produced by cyclic-photophosphorylation, but ${CO_2}-induced$ guard cell membrane hyperpolarization was not related to photosynthesis. Alkalisation of the vacuole was observed when the intact leaf was exposed to $CO_2$, indicating that membrane hyperpolarization was mainly the result of proton efflux.efflux.

• BMB Reports
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• v.47 no.3
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• pp.135-140
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• 2014

The mesenchymal stem cells (MSCs), which are derived from the mesoderm, are considered as a readily available source for tissue engineering. They have multipotent differentiation capacity and can be differentiated into various cell types. Many studies have demonstrated that the MSCs identified from amniotic membrane (AM-MSCs) and amniotic fluid (AF-MSCs) are shows advantages for many reasons, including the possibility of noninvasive isolation, multipotency, self-renewal, low immunogenicity, anti-inflammatory and nontumorigenicity properties, and minimal ethical problem. The AF-MSCs and AM-MSCs may be appropriate sources of mesenchymal stem cells for regenerative medicine, as an alternative to embryonic stem cells (ESCs). Recently, regenerative treatments such as tissue engineering and cell transplantation have shown potential in clinical applications for degenerative diseases. Therefore, amnion and MSCs derived from amnion can be applied to cell therapy in neuro-degeneration diseases. In this review, we will describe the potential of AM-MSCs and AF-MSCs, with particular focus on cures for neuronal degenerative diseases.

• Korean Journal of Veterinary Research
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• v.31 no.1
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• pp.33-40
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• 1991

For the observations of both the membrane properties and the excitability on the unfertilized eggs of female mice, changes of the membrane resistance and the membrane potential by hyerpolarizing current stimulation were recorded. As current-voltage relation was linear over the entire range (-180mV~+60mV), membrane resistance($R_m$) was calculated from the amplitude of electrotonic potential to a given stimulus current. Also the presence of anode-break excitation was confirmed. The results were as follows; 1. There was a linear relation between the membrane resistance and resting membrane potential, the expected input resistance was 61. 4M$\Omega$(resting membrane potential was $-18.9{\pm}8.7mV$, mean${\pm}$SD, n=30). 2. Transient depolarization with overshoot was generated just after hyperpolarizing current stimulus and showed the dependency of stimulus duration. 3. Transient depolarization lasted over 30ms, amplitude of these depolarization was increased by high $Ca^{{+}{+}}$(20mM) and inhibited by $Ca^{{+}{+}}$-antagonist, $Mn^{{+}{+}}$. 4. From the above results, it was suggested that the unfertilized mouse egg showed the characteristics of the excitable cell.

• Herbal Formula Science
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• v.23 no.1
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• pp.121-131
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• 2015

Objectives : This study was conducted to investigate the membrane potential to apply Doksam-tang to a human heart failure model. Methods : The human heart model was built by Luo et al. CellML model, Priebe et al. CellML model, and a human heart mesh file. Doksam-tang gives channel the half maximal inhibitory concentration(IC ₅₀ ), half maximal effective concentration(EC ₅₀ ) values and compounds concentrations. These data load into the laptop with Ubuntu OS, and build the library with the data. Results : While results of the study with the heart failure model shows abnormal membrane potential from the normal heart model, the study with applying Doksam-tang to heart failure model shows restoring membrane potential that is similar to normal heart model. Conclusions : These results of the testings suggest that a conception of novel technique to investigate the effects of Korean herbal medicine.

• Transactions of the Korean hydrogen and new energy society
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• v.18 no.4
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• pp.439-445
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• 2007

Proton exchange membrane Fuel Cells(PEMFCs) have been spotlighted because of their broad potential application for potable electrical devices, automobiles and residential usages. However, their utilization is limited to low temperature operation due to the electrolyte dehydration at high temperature. High temperature PEMFC operation offers high CO tolerance and easy water management. This review presents development of high temperature($120{\sim}200^{\circ}C$) PEMFC. Especially, PEMFC which is based on acid-doped PBI membrane is discussed.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.89.1-89.1
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• 2011

The influence of potential and humidity on the electrochemical carbon corrosion in high temperature polymer electrolyte membrane fuel cells(HT-PEMFCs) is investigated by measuring $CO_2$ emission at different potentials for 30 min using on-line mass spectrometry. These results are compared with low tempterature polymer electrolyte membrane fuel cells(LT-PEMFCs) operated at lower temperature and higher humidity condition. Although the HT-PEMFC is operated at non humidified condition, the emitted $CO_2$ in the condition of HT-PEMFC is more than LT-PEMFC at the same potential in carbon corrosion test. Thus, carbon corrosion shows a stronger positive correlation with the cell temperature. In addition, the presence of a little amount of water activate electrochemical carbon corrosion considerably in HT-PEMFC. With increased carbon corrosion, changes in fuel cell electrochemical characteristics become more noticeable and thereby indicate that such corrosion considerably affects fuel cell durability.

• Applied Chemistry for Engineering
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• v.21 no.1
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• pp.87-92
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• 2010

Desalination experiments were carried out with two types of cell configuration; a CDI cell constructed with carbon electrodes only and a membrane capacitive deionization (MCDI) cell having a cation-exchange membrane on the cathode surface. The salt removal rate and desalination efficiencies increased linearly with increasing the cell potential. Although the same carbon electrodes were used in the desalination experiments, the MCDI cell showed higher salt removal efficiency than that of the CDI cell. The amount of salt removal for the MCDI cell was enhanced by 33.1~135% compared to the CDI cell, depending on the applied cell potential in the range of 0.8~1.2 V. In addition, the current efficiency for the MCDI cell was about 80%, whereas the efficiency was under 40% for the CDI cell. The higher salt removal efficiency in the MCDI cell was attributed to the fact that ions were selectively transported between the electric double layer and the bulk solution in the MCDI cell configuration.

• The Journal of Korean Medicine
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• v.29 no.1
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• pp.95-105
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• 2008

Objectives : Although herbal medicines containing flavonoids have been reported to exert anti-tumor activities, it has not been explored whether Hwang-Jeong (Polygonati sibirici Rhizoma, PsR) exerts anti-tumor activity in human glioma. The present study was therefore undertaken to examine the effect of PsR on cell viability and to determine its underlying mechanism in A172 human glioma cells. Methods : Cell viability was estimated by MTT assay. Reactive oxygen species generation and mitochondrial membrane potential were measured by the fluorescence dyes. The phosphorylation of kinases was evaluated by western blot analysis and caspase activity was estimated using colorimetric assay kit. Results : PsR resulted in loss of cell viability in a dose- and time-dependent manner. PsR did not increase reactive oxygen species (ROS) generation and the PsR-induced cell death was also not affected by antioxidants, suggesting that ROS generation is not involved in loss of cell viability. Western blot analysis showed that PsR treatment caused rapid reduction in phosphorylation of extracellular signal-regulated kinase (ERK) without changes in p38 and Jun-NH2-terminal kinase (JNK). U0126, an inhibitor of ERK, increased the PsR-induced cell death, but inhibitors of p38 and JNK did not affect the cell death. PsR induced depolarization of mitochondrial membrane potential. Caspase activity was not stimulated by PsR and caspase inhibitors did not prevent the PsR-induced cell death. Conclusion : Taken together, these findings suggest that PsR results in human glioma cell death through caspaseindependent mechanisms involving down-regulation of ERK.