• Bulletin of the Korean Chemical Society
• /
• v.20 no.9
• /
• pp.1040-1044
• /
• 1999

A micro porous PTFE membrane desolvator (MMD) was built and evaluated for the on-line removal of organic solvents to facilitate the determination of trace metal contaminants in the solvents by ICP-AES. Three organic solvents, isopropyl alcohol (IPA), methanol, and dimethy sulfoxide (DMSO) were studied. The MMD reduced organic solvent concentration in the sample aerosol stream by 82% to 89%, as indicated by monitoring C(I) emission. Net signal intensity of Fe, Al, and Cu was increasing with higher organic solvent concentration, with the rate of increase being solvent dependent. The signal intensities for Mg and Pb followed the trend with the C(I) signal. Changing the sweep gas flow rate affected the optimum signal intensity. Wine samples were analyzed by the method of standard addition. The concentrations of B, Al, and Mg were determined with a relative precision of less than 2.3%.

• Archives of Pharmacal Research
• /
• v.26 no.8
• /
• pp.597-600
• /
• 2003

Silybin has a potent antibacterial activity, more potent than silymarin II, against gram-positive bacteria without hemolytic activity, whereas it has no antimicrobial activity against gram-negative bacteria or fungi. The mode of action of silybin against the gram-positive bacterial cell was examined by investigating the change in plasma membrane dynamics of bacterial cells using 1 ,6-diphenyl-1,3,5-hextriene (DPH) as a membrane probe and by assessing the inhibition of macromolecular synthesis using radiolabeled incorporation assay. The results showed that silybin inhibited RNA and protein synthesis on gram-positive bacteria.

• Proceedings of the Korean Society for Applied Microbiology Conference
• /
• 2005.06a
• /
• pp.154-164
• /
• 2005

Saccharomyces cerevisiae KNU5377 is a thermotolerant strain, which can ferment ethanol from wasted papers and starch at 40$^{\circ}C$ with the almost same rate as at 30$^{\circ}C$. This strain showed alcohol fermentation ability to convert wasted papers 200 g (w/v) to ethanol 8.4% (v/v) at 40$^{\circ}C$, meaning that 8.4% ethanol is acceptable enough to ferment in the industrial economy. As well, all kinds of starch that are using in the industry were converted into ethanol at 40$^{\circ}C$ with the almost same rate as at 30$^{\circ}C$. Hyperthermic cell killing kinetics and differential scanning calorimetry (DSC) revealed that exponentially growing cells of this yeast strain KNU5377 were more thermotolerant than those of S. cerevisiae ATCC24858 used as a control. This intrinsic thermotolernace did not result from the stability of entire cellular components but possibly from that of a particular target. Heat shock induced similar results in whole cell DSC profiles of both strains and the accumulation of trehalose in the cells of both strains, but the trehalose contents in the strain KNU5377 were 2.6 fold higher than that in the control strain. On the contrary to the trehalose level, the neutral trehalase activity in the KNU5377 cells was not changed after the heat shock. This result made a conclusion that though the trehalose may stabilize cellular components, the surplus of trehalose in KNU5377 strain was not essential for stabilization of whole cellular components. A constitutively thermotolerant yeast, S. cerevisiae KNU5377, was compared with a relatively thermosensitive control, S. cerevisiae ATCC24858, by assaying the fluidity and proton ATPase on the plasma membrane. Anisotropic values (r) of both strains were slightly increased by elevating the incubation temperatures from 25$^{\circ}C$ to 37$^{\circ}C$ when they were aerobically cultured for 12 hours in the YPD media, implying the membrane fluidity was decreased. While the temperature was elevated up to 40$^{\circ}C$, the fluidity was not changed in the KNU5377 cell, but rather increased in the control. This result implies that the plasma membrane of the KNU5377 cell can be characterized into the more stabilized state than control. Besides, heat shock decreased the fluidity in the control strain, but not in the KNU5377 strain. This means also there's a stabilization of the plasma membrane in the KNU5377 cell. Furthermore, the proton ATPase assay indicated the KNU5377 cell kept a relatively more stabilized glucose metabolism at high temperature than the control cell. Therefore, the results were concluded that the stabilization of plasma membrane and growth at high temperature for the KNU5377 cell. Genome wide transcription analysis showed that the heat shock responses were very complex and combinatory in the KNU5377 cell. Induced by the heat shock, a number of genes were related with the ubiquitin mediated proteolysis, metallothionein (prevent ROS production from copper), hsp27 (88-fold induced remarkably, preventing the protein aggregation and denaturation), oxidative stress response (to remove the hydrogen peroxide), and etc.

• Environmental Mutagens and Carcinogens
• /
• v.18 no.2
• /
• pp.116-122
• /
• 1998

The present investigation has been performed to elucidate the effect of pretreatment with low dose of ultraviolet radiation (UV), ethyl methansulfonate (EMS), and bleomycin (BLM) on cell survival and lectin-binding glycoconjugates of plasma membrane in HeLa cells treated with mutagen. The percentage of survival of cells pretreated with 1 mM EMS following treatment with 10 mM EMS was higher than that of cells treated with 10 mM EMS alone. Wheat germ agglutinin (WGA) staining intensity of cells pretreated with 1 mM EMS and subsequently treated with 10 mM EMS was stronger than that of cells treated with 10 mM EMS alone. But, succinylated wheat germ agglutinin (sWGA) staining intensity of cells pretreated with 1 mM EMS and subsequently treated with 10 mM EMS was similar to that of cells treated with 10 mM EMS alone. These results suggest that the acquired resistance to EMS is related to the glycoconjugates containing sialic acid of plasma membrane involved in multidrug resistance or adaptive response in HeLa cells.

• Journal of Nutrition and Health
• /
• v.17 no.4
• /
• pp.297-304
• /
• 1984

The effect of dietary fish oil ( mackerel oil : MO, eel oil : EO) on energy utilization in rats was studied with measurements of various tissue lipoprotein lipase( LPL ) and live and heart mitochondrial respiration. Fatty acid composition of mitrochondrial inner membrane matrix was also investigated. Dietary fat level was 10%( w/w) and reference groups were fed soybean oil (SO), repeseed oil ( RO) and beef tallow( BT ). Activity of LPL was about 60% higher in post-heparin plasma and 2 to 3 times higher in adipose tissue of BT group than fish oil or vegetable oil group. But there was no significant difference between fish oil and vegetable oil groups. Inclusion of EO above 2% (w/w) in dietary fat with fille oil of BT, markedly reduced both post -heparin plasma and adipose tissue LPL. Effects of MO and EO were not different in adipose tissue LPL, but EO was more effective than MO, in reducing post -heparin plasma LPL when mixed fat with varying amount of fish oil was used. Hepatic mitochondria isolated from fish oil-fed group showed the lowest rate of respiration but had P/O ratio comparable to SO and BT groups. On the other hand, cardiac mitochondria of fish oil group showed no difference in all the mitochondrial respiration parameters observed RO group had lowest P/O ratio both in hepatic and cardiac mitochondria. Fatty acid compositions of mitochondrial lipid differ between SO, RO, BT and MO groups, notably in the content of $C_{22:1}$ fatty acid.

• The Korean Journal of Physiology and Pharmacology
• /
• v.22 no.2
• /
• pp.215-223
• /
• 2018

Intracellular $Ca^{2+}$ mobilization is closely linked with the initiation of salivary secretion in parotid acinar cells. Reactive oxygen species (ROS) are known to be related to a variety of oxidative stress-induced cellular disorders and believed to be involved in salivary impairments. In this study, we investigated the underlying mechanism of hydrogen peroxide ($H_2O_2$) on cytosolic $Ca^{2+}$ accumulation in mouse parotid acinar cells. Intracellular $Ca^{2+}$ levels were slowly elevated when $1mM\;H_2O_2$ was perfused in the presence of normal extracellular $Ca^{2+}$. In a $Ca^{2+}-free$ medium, $1mM\;H_2O_2$ still enhanced the intracellular $Ca^{2+}$ level. $Ca^{2+}$ entry tested using manganese quenching technique was not affected by perfusion of $1mM\;H_2O_2$. On the other hand, $10mM\;H_2O_2$ induced more rapid $Ca^{2+}$ accumulation and facilitated $Ca^{2+}$ entry from extracellular fluid. $Ca^{2+}$ refill into intracellular $Ca^{2+}$ store and inositol 1,4,5-trisphosphate ($1{\mu}M$)-induced $Ca^{2+}$ release from $Ca^{2+}$ store was not affected by $1mM\;H_2O_2$ in permeabilized cells. $Ca^{2+}$ efflux through plasma membrane $Ca^{2+}-ATPase$ (PMCA) was markedly blocked by $1mM\;H_2O_2$ in thapsigargin-treated intact acinar cells. Antioxidants, either catalase or dithiothreitol, completely protected $H_2O_2-induced$ $Ca^{2+}$ accumulation through PMCA inactivation. From the above results, we suggest that excessive production of $H_2O_2$ under pathological conditions may lead to cytosolic $Ca^{2+}$ accumulation and that the primary mechanism of $H_2O_2-induced$ $Ca^{2+}$ accumulation is likely to inhibit $Ca^{2+}$ efflux through PMCA rather than mobilize $Ca^{2+}$ ions from extracellular medium or intracellular stores in mouse parotid acinar cells.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.56 no.1
• /
• pp.72-79
• /
• 2011

Here we report a simple screening system using hematoxylin staining (HS) of the root apex. It allowed rapid classification into different aluminum (Al) tolerance from 65 cultivars within one week. Using this system, we selected the most Al-tolerant (Jayae-2) and-sensitive (Pum-2) barley (Hordeum vulgare L.) The results show that the different responses in Al-induced growth inhibition, Al accumulation and expression of plasma membrane (PM) $H^+$-ATPase in root apices of selected two cultivars. It showed strongly Al-induced growth inhibition in a dosedependant manner only in Pum-2 but not in Jayae-2. Aluminum accumulation in root apices (10 mm) was significantly higher in Pum-2 only. The $H^+$-ATPase expression of PM vesicles by western blotting was decreased in Pum-2 but not in Jayae-2 treated with $20{\mu}M$ Al for 24 h. These finding indicate to screen from our system is rapid and reliable and to sustain the expression of PM $H^+$-ATPase at translational level is an important role in root growth as affected by Al.

• The Korean Journal of Zoology
• /
• v.28 no.3
• /
• pp.125-136
• /
• 1985

The present study has been undertaken to elucidate whether there are developmentally regulated proteins in chick myogenesis by observing cellular and plasma membrane glycoproteins by use of labelled-Con A staining. At least three classes and five classes of glycoproteins can be identified in terms of their occurrence and their change in levels, respectively. As to the former, there are glycoproteins which are specific to cellular fraction are eight, those which are specific to plasma membrane are four, and those which occur in both fraction are nine. Likewise, as to the latter, there are glycoproteins which are invariant, those which increase in level, those which decrease, those which increase and subsequently decrease, and those which decrease and subsequently increase. The present experiment reveals that the level of fibronectin does decrease after the fusion and that the apparent conflicting results so far reported may be due to the difference in time point setting during fusion and myotube stages. It is thought to be a general tendency that glycoproteins of high-molecular-weight decrease and those of low-molecular-weight increase in relative levels as the fusion proceeds. These results are suggestive of the fact that a major structural reorganization of glycoproteins does occur in association with myoblast fusion.

• The Korean Journal of Pharmacology
• /
• v.29 no.1
• /
• pp.149-156
• /
• 1993

Intramolecular excimerization of 1,3-di(1-pyrenyl)propane (Py-3-Py) and fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene (DPH) were used to examine the effects of ethanol on the rate and range of lateral diffusion of bulk bilayer structures of plasma membrane vesicles isolated from cultured mouse myeloma cell line Sp2/0-Ag14 (Sp2/0-PMV). In a concentration-dependent manner, ethanol increased the excimer to monomer fluorescence intensity ratio (I'/I) of Py-3-Py in the Sp2/0-PMV and decreased the anisotropy (r), limiting anisotropy $(r_{\infty})$, and order parameter (S) of DPH in the Sp2/0-PMV. This indicates that ethanol increased both the lateral and rotational diffusion of the probes in the Sp2/0-PMV. Selective quenching of DPH by trinitrophenyl groups was utilized to examine the transbilayer asymmetric rotational diffusion of the Sp2/0-PMV. The anisotropy (r), limiting anisotropy $(r_{\infty})$, and order parameter (S) of DPH in the inner monolayer were 0.022, 0.029, and 0.063, respectively, greater than calculated for the outer monolayer of the Sp2/0-PMV. Selective quenching of DPH by trinitrophenyl groups was also utilized to examine the transbilayer asymmetric effects of ethanol on the range of rotational diffusion of the Sp2/0-PMV. Ethanol had a greater fluidizing effect on the outer monolayer as compared to the inner monolayer of the Sp2/0-PMV. It has been proven that ethanol exhibits a selective rather than nonselective fluidizing effect within transbilayer domains of the Sp2/0-PMV.

• Journal of Life Science
• /
• v.31 no.8
• /
• pp.729-735
• /
• 2021

Type 2 diabetes occurs when there is an abnormality in the tissue's ability to absorb glucose. Glucose uptake and metabolism by insulin are the basic mechanisms that maintain blood sugar. Glucose uptake goes through various signaling steps initiated by the binding of insulin to receptors on the cell surface. In line with the foregoing, the purpose of this study was to investigate the effect of 2,7-phloroglucinol-6,6-bieckol (PHB), an active compound isolated from Ecklonia cava, on glucose uptake in 3T3-L1 adipocytes. Notably, PHB increased glucose uptake in a dose-dependent manner owing to the enhanced glucose transporter type 4 (GLUT4) expression in the plasma membrane of 3T3-L1 adipocytes. These effects of PHB were attributed to the phosphorylation of insulin receptor substrate-1 and protein kinase B (PKB or AKT), as well as to the phosphoinositide 3-kinase (PI3K) activation in the insulin signaling pathway. PHB also stimulated 5' AMP-activated protein kinase (AMPK) phosphorylation and activation. The phosphorylation and activation of the PI3K/AKT and AMPK pathways by PHB were identified using wortmannin (a PI3K inhibitor) and compound C (an AMPK inhibitor). In this study, we showed that PHB can increase glucose uptake in 3T3-L1 adipocytes by promoting GLUT4 translocation to the plasma membrane via the PI3K and AMPK pathways. The results indicate that PHB may help improve insulin sensitivity.