• Bulletin of the Korean Chemical Society
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• v.29 no.2
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• pp.352-356
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• 2008

An analytical method has been developed for measuring chlorostyrenes in fish tissue sample. Extraction of chlorostyrenes from fish tissue was carried out by ultrasonication using acetone/n-hexane (5:2, v/v) mixture. Most of the lipids in the extract were eliminated by freezing-lipid filtration, prior to solid-phase extraction (SPE) cleanup. During freezing-lipid filtration, about 90% of the lipids extracted from the fish samples were easily removed without any significant losses of chlorostyrenes. For purification, SPE using Florisil was used for the rapid and effective cleanup. Quantification was performed using gas chromatography-mass spectrometry in the selected ion monitoring mode. Spiking experiments were carried out to determine the recovery, precision, and limits of detection (LODs) of the method. The overall recovery was above 80% in the spiked fish tissue sample at 10 and 100 ng/g levels, respectively. The detection limits for chlorostyrenes were ranged from 0.05 to 0.1 ng/g. This developed method is demonstrated to give efficient recoveries and LODs for detecting chlorostyrenes spiked into fish tissue with high lipid content.

• Journal of Ginseng Research
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• v.20 no.1
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• pp.23-29
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• 1996

The effect of ginseng glycosides and their aglycones on the thermodynamic characteristics of membranes from dipalmitoylphosphatidylcholine (DPPC) was investigated. Total saponins (TS) from Korean red ginseng, Panax ginseng C.A. Meyer, interacted with the Eel Phase of lipid in the Polar region and did not penetrate the deeper glycerol backbone of lipid molecule. From the all investigated components of TS (aglycons and ginsenosides), only 20-(S)-panaxadiol (PD) had an effect similar to TS. High concentration of TS penetrated in hydrophobic Cl-C8 region. The presence of cholesterol did not influence the interaction of TS with DPPC. An elimination of transition, however, took place at 10~100 $\mu\textrm{g}$/ml of TS. DPPC had a low ability to interact with cholesterol (CHL) as compared with other lecithins except ethanolamine. From our results, only TS and PD, at high concentrations (100 mol%), influenced the phase transition of mixture of DPPC:CHL.

• Journal of the Korean Applied Science and Technology
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• v.39 no.5
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• pp.720-726
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• 2022

The behavior changes of the lipid bilayer, induced by the hydroxybutyric-acid incorporation, were investigated with respect to each phase of the layer using fluorescence intensity change. Spherical phospholipid bilayers, called vesicles, were prepared using an emulsion technique. Only in the aqueous inside of the vesicles was encapsulated 8-Aminonaphthalene-1,3,6-trisulfonic-acid-disodium-salt(ANTS). p-Xylene-bis-N-pyridinium-bromide(DPX) was included as a quencher only outside of the vesicles. The fluorescence scale was calibrated with the ANTS-encapsulated vesicles in DPX-dispersed-buffer taken as 100% and the mixture of ANTS and DPX in the buffer as 0%. Hydroxybutyric-acid addition into the vesicle solution led the change in the bilayer. The change was found to be related to the phase of each layer according to the ratio of hydroxybutyric-acid to lipid. These results seem to depend on the stability of the vesicles, due to the osmotic and volumetric effects on the arrangement in both head-group and tail-group.

• Korean Journal of Food Science and Technology
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• v.36 no.1
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• pp.19-24
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• 2004

Effect of polyphenolic compounds from green tea leaves and surfactant micelles on lipid oxidation in corn oil-in-water emulsion (O/W) wag determined. Concentrations of polyphenolic compound and surfactant in continuous phase of O/W were measured. Particle size of O/W with 17 mM Brij 700 and 5% corn oil increased with increasing concentration of polyphenolic compound (100-200 ppm). Concentration of surfactant in the continuous phase was lower than that of control. Lipid oxidation rates, as determined by the formation of lipid hydroperoxides and headspace hexanal, in O/W emulsions containing polyphenolic compounds decreased with increasing concentration of polyphenolic compounds (100-200 ppm). Inhibition of hydroperoxide and headspace hexanal produced via lipid oxidation by polyphenolic compounds in O/W was BHT>procyanidin B3-3-O-gallate>(+)-gallocatechin >(+)-catechin.

• Journal of the Korean Chemical Society
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• v.67 no.2
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• pp.89-98
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• 2023

The cell membrane, also known as the biological membrane, surrounds every living cell. The main components of cell membranes are lipids and therefore called as lipid membranes. These membranes are mainly made up of a two-dimensional lipid bilayer along with integral and peripheral proteins. The complex nature of lipid membranes makes it difficult to study and hence artificial lipid membranes are prepared which mimic the original lipid membranes. These artificial lipid membranes are prepared from phospholipid vesicles (liposomes). The liposomes are formed when self-forming phospholipid bilayer comes in contact with water. Liposomes can be unilamellar or multilamellar vesicles which comprises of phospholipids that can be produced naturally or synthetically. The phospholipids are non-toxic, biodegradable and are readily produced on a large scale. These liposomes are mostly used in the drug delivery systems. This paper offers comprehensive literature with insights on developing basic understanding of lipid membranes from its structure, organization, and phase behavior to its potential use in biomedical applications. The progress in the field of artificial membrane models considering methods of preparation of liposomes for mimicking lipid membranes, interactions between the lipid membranes, and characterizing techniques such as UV-visible, FTIR, Calorimetry and X-ray diffraction are explained in a concise manner.

• Electrical & Electronic Materials
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• v.9 no.7
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• pp.696-701
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• 1996

In this study, deposited lipid membranes on the electrode and detected thermally stimulated displacement current generated from it. The researchers examined displacement current of electric conduction organic monolayer generated due to orient change of monolayers alkylchain and changed of dipole moment vertical component due to thermally stimulated. We paid attention to the phase transition temperature obtained by the thermally stimulated displacement current of lipid membrane layers this time. We detected the thermally stimulated displacement current peak of layers. From above results the transition temperature dilauroylphosphatidylcholine layers is about 43.deg. C. This study also compared above results with those obtained by differential thermal analysis method.

• Bulletin of the Korean Chemical Society
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• v.31 no.2
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• pp.372-378
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• 2010

Membrane disruption by an antimicrobial peptide, protegrin-1 (PG-1), was investigated by measuring the $^2H$ solid-state nuclear magnetic resonance (SSNMR) spectra of 1-palmitoyl-$d_{31}$-2-oleoyl-sn-glycero-3-phosphatidylcholine (POPC_$d_{31}$) in the mixture of PG-1 and POPC_$d_{31}$ lipids deposited on thin cover-glass plates. The experimental line shapes of anisotropic $^2H$ SSNMR spectra measured at various peptide-to-lipid (P/L) ratios were simulated reasonably by assuming the mosaic spread of bilayers containing pore structures or the coexistence of the mosaic spread of bilayers and a fast-tumbling isotropic phase. Within a few days of incubation in the hydration chamber, the pores were formed by the peptide in the POPC_$d_{31}$ and POPC_$d_{31}$/cholesterol membranes. However, the formation of the pores was not clear in the POPC_$d_{31}$/1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylglycerol (POPG) membrane. Over a hundred days after hydration, a rapidly rotating isotropic phase increased in the POPC_$d_{31}$ and the POPC_$d_{31}$/cholesterol membranes with the higher P/L ratios, but no isotropic phase appeared in the POPC_$d_{31}$/POPG membrane. Cholesterol added in the POPC bilayer acted as a stabilizer of the pore structure and suppressed the formation of a fast-tumbling isotropic phase.

• BMB Reports
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• v.43 no.8
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• pp.535-540
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• 2010

Patients with hemorrhagic fever with renal syndrome (HFRS) often exhibit altered serum lipid and lipoprotein profile during the oliguric phase of the disease. Serum lipid and lipoprotein profiles were assessed during the oliguric and recovery phases in six male patients with HFRS. In the oliguric phase of HFRS, the apolipoprotein (apo) C-III content in high-density lipoproteins (HDL) was elevated, whereas the apoA-I content was lowered. The level of expression and activity of antioxidant enzymes were severely reduced during the oliguric phase, while the cholesteryl ester transfer protein activity and protein level were unchanged between the phases. In the oliguric phase, electromobility of $HDL_2$ and $HDL_3$ was faster than in the recovery phase. Low-density lipoprotein (LDL) particle size was smaller and the distribution was less homogeneous. Patients with HFRS in the oliguric phase had severely modified lipoproteins in composition and metabolism.

• Analytical Science and Technology
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• v.28 no.2
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• pp.106-111
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• 2015

Changes in antimicrobial peptide-lipid mixtures were investigated using ³¹P solid-state nuclear magnetic resonance spectroscopy. An antimicrobial peptide, protegrin-1, and phosphatidylcholine were deposited on a thin cover glass and incubated under a relative humidity of 95%. The changes in the mixtures were observed after hydration or air-drying. How repetitive hydration and drying changed the phase of the sample was also observed. The degrees of disruption of the well-aligned bilayers of phosphatidylcholine were determined quantitatively by simulating the experimental spectra. The peptide-lipid mixtures changed reversibly after hydration and drying, and the samples reached an equilibrium state after several repetitions.

• Nuclear Engineering and Technology
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• v.2 no.3
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• pp.179-183
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• 1970

(4-$^{14}$ C) Cholesterol was administered to the leaves of Solanum andigena during photoperiodic induction. Radioactive products converted from cholesterol were studied by thin-layer chromatography and gas-chromatography. The major products from cholesterol were shown to be esterified cholesterol in lipid and solanine in the aqueous ethanolic phase in SD-and LD-leaves. The radioactive solanidine was isolated by chromatography and crystallized to constant specific activity. Short-day condition did not stimulate the conversion of cholesterol into solanine in the leaves, but both groups of leaves converted cholesterol into solanine at the about same rate. Incorporation of radioactivity into aqueous ethanolic phase of tubers and stolons, containing storied glycoalkaloid, was very much higher than that into lipid phase, contrary to those in the leaves and the stems.