• Korean Journal of Clinical Laboratory Science
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• v.51 no.1
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• pp.78-85
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• 2019

Membrane proteins are involved in many common diseases, including heart disease and cancer. In various disease states, such as cancer, abnormal signaling pathways that are related to the membrane proteins cause the cells to divide out of control and the expression of membrane proteins can be altered. Membrane proteins have the hydrophobic environment of a lipid bilayer, which makes an analysis of the membrane proteins notoriously difficult. Therefore, this study evaluated the efficacy of two different methods for optimal membrane protein extraction. High-speed centrifuge and reagent-based method with a -/+ filter aided sample preparation (FASP) were compared. As a result, the high-speed centrifuge method is quite effective in analyzing the mitochondrial inner membranes, while the reagent-based method is useful for endoplasmic reticulum membrane analysis. In addition, the function of the membrane proteins extracted from the two methods were analyzed using GeneGo software. GO processes showed that the endoplasmic reticulum-related responses had higher significance in the reagent-based method. An analysis of the process networks showed that one cluster in the high-speed centrifuge method and four clusters in the reagent-based method were visualized. In conclusion, the two methods are useful for the analysis of different subcellular membrane proteins, and are expected to assist in selecting the membrane protein extraction method by considering the target subcellular membrane proteins for study.

• Membrane Journal
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• v.8 no.4
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• pp.235-242
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• 1998

Pervaporation separation of methyl tert-butyl ether (MTBE) and methanol (MeOH) mixture, of which the former compound is well known as the octane booster was carried out. Poly(vinyl alcohol) (PVA) membranes crosslinked with poly(acrylic acid) which have been successfully applied on the water-alcohol mixtures were used in this study. The PVA/PAA ratio in the crosslinked membranes was 95/5, 90/10, 85/15, 80/20, and 75/25 by weight. The operating temperatures were 30, 40, and 50$\circ$C, and the compositions of MTBE and MeOH to be separated were 95/5, 90/10, and 80/20 (MTBE/MeOH) solutions. PVA/PAA=85/15 membrane showed the separation factor $\alpha_{MeOH/MTBE}$=4000 and the permeation rate of 10.1 g/m$^2$hr for MTBE/MeOH=80/20 solution at 50$\circ$. When the same membrane was used, the separation factor and permeation rate for MTBE/MeOH=90/10 solution at 40$\circ$C were $\alpha_{MeOH/MTBE}$=6000 and 8.5 g/m$^2$hr, respectively. Also, the hydrophilic/hydrophobic balance of the membranes would take an important role in the relationships between the membranes and separation performances in terms of the flux and the separation factor.

• Journal of Life Science
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• v.31 no.5
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• pp.527-535
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• 2021

Lysosomes are organelles surrounded by membranes that contain acid hydrolases; they degrade proteins, macromolecules, and lipids. According to nutrient conditions, lysosomes act as signaling hubs that regulate intracellular signaling pathways and are involved in the homeostasis of cells. Therefore, the lysosomal dysfunction occurs in various diseases, such as lysosomal storage disease, neurodegenerative diseases, and cancers. Multiple forms of stress can increase lysosomal membrane permeabilization (LMP), resulting in the induction of lysosome-mediated cell death through the release of lysosomal enzymes, including cathepsin, into the cytosol. Here we review the molecular mechanisms of LMP-mediated cell death and the enhancement of sensitivity to anticancer drugs. Induction of partial LMP increases apoptosis by releasing some cathepsins, whereas massive LMP and rupture induce non-apoptotic cell death through release of many cathepsins and generation of ROS and iron. Cancer cells have many drug-accumulating lysosomes that are more resistant to lysosome-sequestered drugs, suggesting a model of drug-induced lysosome-mediated chemoresistance. Lysosomal sequestration of hydrophobic weak base anticancer drugs can have a significant impact on their subcellular distribution. Lysosome membrane damage by LMP can overcome resistance to anticancer drugs by freeing captured hydrophobic weak base drugs from lysosomes. Therefore, LMP inducers or lysosomotropic agents can regulate lysosomal integrity and are novel strategies for cancer therapy.

• Journal of the Korea Organic Resources Recycling Association
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• v.19 no.1
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• pp.64-78
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• 2011

Surface of hydrophobic polyethylene membrane was modified to become hydrophilic by ion beam irradiation. Submerged membrane filtration reactors contained pristine membrane or surface-modified membrane and the influent to reactors was pickled radish wastewater. The objectives of this study was to investigate the variation of flux and pressure and the characteristics of pollutant removal such as organics, suspended solids and nutrients with time. The result of experiments using intermittent pristine membrane showed the occurrence of severe fouling by increasing permeate pressure rapidly in case of pickled radish wastewater but in synthetic wastewater, this phenomenon was not occurred. In experiments of variation flux after chemical cleaning and water cleaning in pristine membrane, chemical cleaning must be necessary for renewals of pollutant membrane. Performance of intermittent operation is higher than that of continuous operation. Reaching fouling time in the case of surface-modified membrane is 6 times as long as pristine membrane. According this reason, replacement expense of surface-modified membrane could be 1/6 of that of pristine membrane. Effluent from this process was relatively good water quality and performance in the removal efficiency of SS, nitrogen and phosphorus was particularly higher.

• The Korean Journal of Physiology and Pharmacology
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• v.3 no.6
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• pp.565-570
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• 1999

Intracellular accumulation of bile acids in the hepatocytes during cholestasis is thought to be pathogenic in cholestatic liver injury. Due to the detergent-like effect of the hydrophobic bile acids, hepatocellular injury has been attributed to direct membrane damage. However histological findings of cholestatic liver diseases suggest apoptosis can be a mechanism of cell death during cholestatic liver diseases instead of necrosis. To determine the pattern of hepatocellular toxicity induced by bile acid, we incubated primary cultured rat hepatocytes with a hydrophobic bile acid, Glycochenodeoxycholate (GCDC), up to 5 hours. After 5 hours incubation with $400\;{\mu}M$ GCDC, lactate dehydrogenase released significantly. Cell viability, quantitated in propidium iodide stained cells concomitant with fluoresceindiacetate was decreased time- and dose-dependently. Most nuclei with condensed chromatin and shrunk cytoplasm were heavily labelled time- and dose-dependently by a positive TUNEL reaction. These findings suggest that both apoptosis and necrosis are involved in hepatocytes injury caused by GCDC.

• Transactions of the Korean hydrogen and new energy society
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• v.27 no.6
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• pp.660-669
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• 2016

A fluorinated-sulfonated, hydrophobic-hydrophilic copolymer was planed subsequently synthesized using typical nucleophilic substitution polycondensation reaction. A novel AB and ABA (or BAB) block copolymers were synthesized using sBCPSBP (sulfonated 4,4'-bis[4-chlorophenyl)sulfonyl]-1,1'-biphenyl), DHN (1,5-dihydroxynaphthalene), DFBP (decafluorobiphenyl) and HFIP (4,4'-hexafluoroisopropylidenediphenol). All block copolymers were easily cast and made into clear films. The structure and synthesized copolymers and corresponding membranes were analyzed using GPC (gel permeation chromatography), $^1H$-NMR ($^1H$ nuclear magnetic resonance) and FT-IR (Fourier transform infrared). TGA (Thermogravimetric analysis) and DSC (differential scanning calorimetry) analysis showed that the prepared membranes were thermally stable, so that elevated temperature fuel cell operation would be possible. Hydrophobic/hydrophilic phase separation and clear ionic aggregate block morpology was confirmed in both triblock and diblock copolymer in AFM (atomic force microscopy), which may be highly related to their proton transport ability. A sulfonated BAB triblock copolymer membrane with an ion-exchange capacity (IEC) of 0.6 meq/g has a maximum ion conductivity of 40.3 mS/cm at $90^{\circ}C$ and 100% relative humidity.

• Bulletin of the Korean Chemical Society
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• v.31 no.12
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• pp.3740-3744
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• 2010

A typically designed 'Peptide Lego' has two distinct surfaces: a hydrophilic side that contains the complete charge distribution and a hydrophobic side. In this article, we describe the fabrication of a unique lego-type peptide with the AEAEYAKAK sequence. The novel peptide with double amphiphilic surfaces is different from typical peptides due to special arrangement of the residues. The results of CD, FT-IR, AFM and DLS demonstrate that the peptide with the random coil characteristic was able to form stable nanostructures that were mediated by non-covalent interactions in an aqueous solution. The data further indicated that despite its different structure, the peptide was able to undergo self-assembly similar to a typical peptide. In addition, the use of hydrophobic pyrene as a model allowed the peptide to provide a new type of potential nanomaterial for drug delivery. These efforts collectively open up a new direction in the fabrication of nanomaterials that are more perfect and versatile.

• Membrane Journal
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• v.19 no.2
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• pp.157-164
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• 2009

Bio-butanol recovery by pervaporation was performed with dense and composite polydimethylsiloxane (PDMS) membranes. The pervaporative behavior of the membranes was investigated as a function of operation temperature $(20{\sim}40^{\circ}C)$ and membrane thickness $(100{\sim}1{\mu}m)$ using a series of aqueous BtOH model solutions $(1{\sim}5wt%)$. With the increment of the BtOH concentration in feed, the Butanol concentration in permeate, pervaporation selectivity of Butanol over water and Butanol permeation flux increased. As the operating temperature of feed solutions increased, the BtOH concentration in permeate, pervaporation selectivity and permeation flux increased markedly. As the thickness of the PDMS membrane decreased, permeation flux increased but pervaporation selectivity decreased. These results were explained in terms of high solubility and low diffusion resistance of BtOH over water toward hydrophobic and rubbery PDMS membranes.

• Membrane Journal
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• v.24 no.4
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• pp.268-275
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• 2014

The water-insoluble poly(phenoxy-methylamino)phosphazene has been synthesized and investigated as the new type of diagnostic membrane for the measurements of blood glucose level. Final absorbances at 680 nm through activated polyphosphazene membranes were measured at various concentration of glucose in blood. The end-point results of varing absorbance values according to time (K/S) were used to obtain glucose concentration. The effects of substitution rates with hydrophilic methylamino groups and hydrophobic phenoxy groups on the measurements of glucose concentration were studied. Dose-response slope (DRS) values between glucose concentration and K/S values increased as the hydrophilic substitution rates increased. However, in less than 5% of the hydrophilic substitution rates, DRS values are too low, and in more than 25% of the hydrophilic substitution rates, because DRS increased rapidly, it was difficult to measure exact concentration level of glucose.

• Clean Technology
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• v.5 no.2
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• pp.69-78
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• 1999

Separation characteristics of cutting oil-in-water emulsions were studied experimentally by using various kinds of flat-type microfiltration and ultrafiltration membranes. For ultrafiltration membranes the permeation behavior of cutting oil emulsions obeys the film model, whereas a significant deviation from the model was observed for ASYPOR microfiltration membranes. The experimental data obtained for all the membranes showed that the effect of operating pressure on the permeation flux of oil-in-water emulsions is not very significant. At low transmembrane pressures the permeation flux decreased gradually with increasing filtration time, whereas the permeation flux at high transmembrane pressures decreased steeply for early filtration time. However, every flux eventually reached a constant value that depends only on the applied transmembrane pressure. For the hydrophobic polycarbonate microfiltration membrane the permeation flux increased with the filtration time. The critical permeation pressures were also determined from the data obtained from unstirred cell experiments.