• Journal of Life Science
• /
• v.21 no.2
• /
• pp.251-256
• /
• 2011

EGCG, catechins in green tea, is a kind of phytochemical. Through the regulation of signal pathways, EGCG has been known to show anti-oxidant and anti-tumor effects in cells. In this study, we investigated the apoptotic effects of EGCG through AMP-activated protein kinase (AMPK) signal pathways, including hypoxia inducible factor-1 alpha (HIF-$1{\alpha}$). The experiments were performed in B16F10 melanoma cells in a hypoxic state. AMPK is activated by ATP consumption such as nutrient deficiency, exercise, heat shock, etc. The activated AMPK that plays an important role as an energy sensor inhibits proliferation of cancer cells, as well as inducing apoptosis. HIF-$1{\alpha}$, the primary transcriptional regulator of the response to oxygen deprivation, plays a critical role in modulating tumor growth and angiogenesis in a hypoxic state. The apoptotic effects of EGCG were studied in B16F10 cells in a hypoxic state. The results show that EGCG inhibits the transcriptional activity of HIF-$1{\alpha}$ and induces apoptosis. These observations suggest that EGCG may exert inhibitory effects of angiogenesis and control tumor cell growth in hypoxic melanoma cells.

• Journal of Life Science
• /
• v.19 no.4
• /
• pp.423-428
• /
• 2009

Selenium was investigated using human origin preadipocytes to see whether it possesses preventive or therapeutic effects for obesity. Unveiling the potential of selenium in the reduction of adipogenesis can help predict the therapeutic capabilities of selenium in obesity. In the present study, the molecular mechanism of the inhibition of adipogenesis by selenium was explored to unravel the involvement of the AMP-activated protein kinase. There is emerging evidence that AMPK, a sensor of cellular energy status, is a possible molecular target of controlling adipocyte differentiation on the basis of discovery that AMPK is responsible for the major metabolic responses to exercise, and integration of nutritional and hormonal signals to modulate feeding behavior or energy expenditure in the hypothalamus. Treatment of selenium resulted in inhibition of the adipocyte differentiation process and induction of mature apoptosis in 3T3-L1 adipocytes. We hypothesized that selenium may exert anti-adipogenic potential though modulating AMPK. We have found that selenium significantly activated AMPK and phosphorylated its substrate acetyl-CoA carboxylase ($ACC-serine^{79}$) during the inhibitory process of adipocytes. Also, the inhibition process of adipocyte differentiation by selenium was comparable to either reveratrol or a synthetic AMPK activator, AICAR (5-aminoimidazole-4-carboxamide-1-${\beta}$-D-ribofuranoside). To evaluate the involvement of AMPK in anti-lipogensis, we applied AICAR and Compound C, an AMPK inhibitor, to 3T3-L1-adipocytes and found that AMPK is required for the adipocyte differentiation blocking process. These results suggest that selenium has a potential to control adipogenesis and that this effect is mediated by AMPK, an essential kinase for both inhibition of adipocyte differentiation and apoptosis of mature adipocytes.

• Journal of Photoscience
• /
• v.9 no.2
• /
• pp.302-304
• /
• 2002

pharaonis phoborhodopsin (ppR), a photophobic sensor of haloalkaliphilic bacteria, Natronobacterium phar-aonis, has retinal as a chromophore covalently bound to Lys in G-helix via a protonated Schiff base (PSB), as is the same as bacteriorhodopsin (bR). For ppR, the corresponding counter-ion is Asp residue (Asp75) located in C-helix. Here we investigated the influence of the protonated state of this counter-ion and its location on the chromophore configuration. Under alkaline condition, the chromophore configuration of D75E mutant was analyzed by HPLC. D75E had a much larger content of 13-cis isomer: the ratio of 13-cis to all-trans was 6:4 while the wild-type had this ratio of 1 :9. On the other hand, under acidic condition where Glu was associated, D75E had no 13-cis retinal isomer. Mutants whose Asp75 was replaced by neutral amino acids (D75N and D75Q) did not contain 13-cis retinal. Furthermore, retinal isomer compositions and the change in the visible ab- sorption spectra (indicating the dissociation state of Glu75) were measured under varying pH, and these were almost the same dependencies. These results indicate that an important factor determining the 13-cis isomer content is the presence of negative charge of the counter-ion against PSB, but not the size of this residue. Com- parison between the wild-type and D75E in alkaline solutions indicates the influence of the location of the counter-ion.

• Proceedings of the Korean Society of Plant Pathology Conference
• /
• 2003.10a
• /
• pp.101.1-101
• /
• 2003

Lipopolysaccharide, siderophore, and cyclic dipeptide have been shown to be necessary for ISR induction by pseudomnads. However, there is no report on cloning of genes or generating specific mutants involving in ISR activity. A biological control bacteium P. chlororaphis O6 induces resistance to Erwinia carotovora subsp. carotovara SCCI in tobacco and induces drought resistance in Arabidopsis. To isolate genes involved in ISR activity and induction of drough resistance of O6, we constructed Tn5 mutants and were used to screen for ISR activity and drought resistance activity using microtiter assay with tobacco and Arabidopsis. Thirty-three ISR-deficient mutants were selected, and the nine ISR-deficient mutants were also lost activity of drought resistance. The flanking sequence analysis of the ISR and drought resistance-deficient mutants showed that a gacS gene encoding a two-component sensor kinase, and a mce gene encoding a protein involved in mycobacterial cell entry were mutated. The flanking sequence of each Tn5 mutant altered ISR activity is currently under investigation. These results indicate that gacS and mce are important genes in induction of ISR activity and drought resistance of P. chlororaphis O6. Our works will open opportunities for identification of bacterial genes or traits that are involved in ISR activity and induced drought resistance of P. chlororaphis O6.

• Journal of Ginseng Research
• /
• v.33 no.1
• /
• pp.59-64
• /
• 2009

$Ca^{2+}$ and calmodulin (CaM), a key $Ca^{2+}$ sensor in all eukaryotes, have been implicated for defense responses of plants. Eukaryotic CaM contains four structurally and functionally similar $Ca^{2+}$ domains named I, II, III and IV. Each $Ca^{2+}$ binding loop consists of 12 amino acid residues with ligands arranged spatially to satisfy the octahedral symmetry of $Ca^{2+}$ binding. To investigate the altered gene expression and the role of CaM in ginseng plant defense system, cDNA clone containing a CaM gene, designated PgCaM was isolated and sequenced from Panax ginseng. PgCaM, which has open reading frame of 450 nucleotides predicted to encode a precursor protein of 150 amino acid residues. Its sequence shows high homologies with a number of other CaMs, with more similarity to CaM of Daucus carota (AAQ63461). The expression of PgCaM in different P. ginseng organs was analyzed using real time PCR. The results showed that PgCaM expressed at different levels in young leaves, shoots, and roots of 3-week-old P. ginseng. In addition, the expressions of PgCaM under different abiotic stresses were analyzed at different time intervals.

• The Journal of Korean Physical Therapy
• /
• v.13 no.3
• /
• pp.509-527
• /
• 2001

The Sun's ray is composed of Infrared(49%), Visible light(40%) and Ultra violet(11%), however the ray getting to the earth is FIR(Far infrared; 60%), IR(Infrared; 20%), and UV(Ultra Violet; 20%). Human beings has utilized FIR already from time immemorial. Hershel found out Infrared for the first time. in the Industrial Revolution the Infrared and FIR had been begun to use making products. In these days, with contemporary science FIR would be begun to clear up the implication in the human body and organic compound. IR classified by wavelength three parts NlR, MIR, FIR. There is FIR which is radiated from healthy human body the wave length is 8-l4m. The human body is composed of proteins which get easily changed by a thermal factor (about 42 $^{\circ}$C over). FIR with low temperature can deeply penetrate on the human body composed things without troublesomes, since FIR has effectively operated on the human body at low temperature (35-40 $^{\circ}$C). When FlR penetrated on the human body. it would inhibit the abnormal genes and cells expression, and then information of DNA and RNA would be reexpressed for arranging DNA and RNA abnormal state. As FlR's receptors in the body, it could be presumed that N-glycosyl linkage of purine and deoxyribose, RNA splicing process, and Heat shock protein. To take the FIR which was a optimized wavewlength and strength, at first, we induced the characteristic algorithm and the computerized programing. Then we formed that the formular of optimized FIR with physical, mathematical logic and theory. especially, Plank, Kirchhoff, Wien, Stefan-Boltzmann's logic and law. In the long run, the formular was induced with integration mathematical, since we had to know the molecular wavelength. Based on the induced formular as above, we programmed the optimized FlR radiating computerized program. In this research, we designed the eletronic circuit f3r interfacing with human body to diagnosis and treatment with FIR sensor which radiated FIR wavelength optimized.

• Korean Journal of Optics and Photonics
• /
• v.14 no.1
• /
• pp.97-102
• /
• 2003

Multi-channel images of 11-MUA(11-Mercaptoundecanoic acid) and 11-MUOH(11-Mercaptoundecanol) self-assembled monolayers were obtained by using two-dimensional surface plasmon resonance (SPR) absorption. The patterning process was simplified by exploiting direct photo-oxidation of thiol bonding (photolysis) instead of conventional photolithography. Sharper images were resolved by using a white light source in combination with a narrow bandpass filter in the visible region, minimizing the diffraction patterns on the images. The line profile calibration of the image contrast caused by different resonance conditions at each point on the sensor surface (at a fixed incident angle) enables us to discriminate the monolayer thickness in nanometer scale. Furthermore, there is no signal degradation such as photo bleaching or quenching, which are common in the detection methods based on fluorescence.

• BMB Reports
• /
• v.34 no.4
• /
• pp.385-389
• /
• 2001

Insulin-like growth factor binding protein-1 (IGFBP-1) appears to be an important modular of the insulin growth factor (IGF) bioactivity in metabolic disease and chronic hypoxia. Treatment of desferrioxamine (Dfo), cobalt, or nickel in HepG2 cells stimulated the expression of IGFBP1 mRNA as hypoxia. However, the presence of ferric ammonium citrate (FAC) in the 1% $O_2$ decreased the upregulation of the IGFBP-1 mRNA expression. In addition, actinomycin D and cycloheximide abolished the increase in the expression of IGFBP-1 mRNA that was induced by Dfo and transition metals (cobalt and nickel). To obtain further information about the putative oxygen sensor, we postulate that putative heme proteins, responsible for the oxygen-sensing process in HepG2 cells, should be sensitive to hypoada. The mechanism of these upregulations of the IGFBP-1 mRNA expression by Dfo and transition metals was investigated by treatment with 2 mM of 4,6-dioxoheptanoic acid (DHA), an inhibitor of heme biosynthesis. The results showed that 1% $O_2$-, Dfo-, cobalt-, or nickel induced IGFBP-1 mRNA expressions in HepG2 cells were all markedly inhibited when the heme synthesis was blocked by DHA. We suggest that the IGFBP-1 mRNA expression in the HepG2 cell is regulated by 1% $O_2$, Dfo, cobalt, or nickel, implicating the involvement of the putative heme-containing oxygensensing molecule.

• The Korean Journal of Physiology and Pharmacology
• /
• v.5 no.5
• /
• pp.367-371
• /
• 2001

The chromosome 7-linked long QT syndrome (LQT2) is caused by mutations in the human ether-a- go-go-related gene (HERG) that encodes the rapidly activating delayed rectifier $K^+$ current, $I_{Kr},$ in cardiac myocytes. Different types of mutations have been identified in various locations of HERG channel. One of the mechanisms for the loss of normal channel function is due to membrane trafficking of channel protein. The decreased channel function in some deletion mutants appears to be due to loss of coupling with wild type HERG to form the functional channel as the tetramer. Most of missense mutants with few exceptions could interact with wild type HERG to form functional tetramer and caused dominant negative suppression with co-injection with wild type HERG showing variable effects on current amplitude, voltage dependence, and kinetics of activation and inactivation. Two missense mutants at pore regions of HERG found in Japanese LQT2 (A614V and V630L) showed accentuated inward rectification due to a negative shift in steady-state inactivation and fast inactivation. One mutation in S4 region (R534C) produced a negative shift in current activation, indicating the S4 serving as the voltage sensor and accelerated deactivation. The C-terminus mutation, S818L, could not express the current by mutant alone and did not show dominant negative suppression with co-injection of equal amount of wild type cRNA. Co-injection of excess amount of mutant with wild type produced dominant negative suppression with a shift in voltage dependent activation. Therefore, multiple mechanisms are involved in different mutations and functional abnormality in LQT2. Further characterization with the interactions between various mutants in HERG and the regulatory subunits of the channels (MiRP1 and minK) is to be clarified.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.02a
• /
• pp.549-549
• /
• 2012

Early detection of cancer biomarkers in the blood is of vital importance for reducing the mortality and morbidity in a number of cancers. From this point of view, immunosensors based on nanowire (NW) and carbon nanotube (CNT) field-effect transistors (FETs) that allow the ultra-sensitive, highly specific, and label-free electrical detection of biomarkers received much attention. Nevertheless 1D nano-FET biosensors showed high performance, several challenges remain to be resolved for the uncomplicated, reproducible, low-cost and high-throughput nanofabrication. Recently, two-dimensional (2D) graphene and reduced GO (RGO) nanosheets or films find widespread applications such as clean energy storage and conversion devices, optical detector, field-effect transistors, electromechanical resonators, and chemical & biological sensors. In particular, the graphene- and RGO-FETs devices are very promising for sensing applications because of advantages including large detection area, low noise level in solution, ease of fabrication, and the high sensitivity to ions and biomolecules comparable to 1D nano-FETs. Even though a limited number of biosensor applications including chemical vapor deposition (CVD) grown graphene film for DNA detection, single-layer graphene for protein detection and single-layer graphene or solution-processed RGO film for cell monitoring have been reported, development of facile fabrication methods and full understanding of sensing mechanism are still lacking. Furthermore, there have been no reports on demonstration of ultrasensitive electrical detection of a cancer biomarker using the graphene- or RGO-FET. Here we describe scalable and facile fabrication of reduced graphene oxide FET (RGO-FET) with the capability of label-free, ultrasensitive electrical detection of a cancer biomarker, prostate specific antigen/${\alpha}$ 1-antichymotrypsin (PSA-ACT) complex, in which the ultrathin RGO channel was formed by a uniform self-assembly of two-dimensional RGO nanosheets, and also we will discuss about the immunosensing mechanism.