• Archives of Pharmacal Research
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• v.13 no.3
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• pp.246-251
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• 1990

Intermolecular interaction between barbiturates and membrane components such as phospholipid and cholesterol were investigated on $^1$H-NMR spectra and infrared spectra. According to previous reports, barbiturates interacted with phospholipid through intermolecular hydrogen bonds. We also investigated thi observation using dipalmitoyl-phosphatidylcholine (DPPC) as phospholipid in deuterochloroform, and characterized quantitatively. Also, the observed drug could interact with cholesterol which is one of the major components of biomembranes through hydrogen bonds. It was the carbonyl groups of barbiturate and the hydroxyl group of cholesterol that formed hydrogen bond complex. In addition to spectroscopic studies, we investigated the direct effect of phenobarbital on lipid multibilayer vesicles, whose compositions were varied, by calorimetric method. Phenobarbital caused a reduction in the temperature of phase transition of vesicles. These studies may provided a basis for interpreting the mode of action of barbiturates.

• The Korean Journal of Physiology
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• v.22 no.2
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• pp.307-318
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• 1988

Properties of succinate transport were examined in basolaterat membrane vesicles (BLMV) isolated from rabbit renal cortex. An inwardly directed $Na^+$ gradient stimulated succinate uptake and led to a transient overshoot. $K^+,{\;}Li^+,{\;}Rb^+$ and choline could not substitute for $Na^+$ in the uptake process. The dependence of the initial uptake rate of succinate on $Na^+$ concentration exhibited sigmoidal kinetics, indicating interaction of more than one $Na^+$ with transporter Hill coefficient for $Na^+$ was calculated to be 2.0. The $Na^+-dependent$ succinate uptake was electrogenic, resulting in the transfer of positive charge across the membrane. The succinate uptake into BLMV showed a pH optimum at external pH $7.5{\sim}8.0$, whereas succinate uptake into brush border membrane vesicles (BBMV) did not depend on external pH. Kinetic analysis showed that a Na-dependent succinate uptake in BLMV occurred via a single transport system, with an apparent Km of $15.5{\pm}0.94{\;}{\mu}M$ and Vmax of $16.22{\pm}0.25{\;}nmole/mg{\;}protein/min$. Succinate uptake was strongly inhibited by $4{\sim}5$ carbon dicarboxylates, whereas monocarboxylates and other organic anions showed a little or no effect. The succinate transport system preferred dicarboxylates in trans-configuration (furmarate) over cis-dicarboxylates (maleate). Succinate uptake was inhibited by the anion transport inhibitors DIDS, SITS and furosemide, and $Na^+-coupled$ transport inhibitor harmaline. These results indicate the existence of a $Na^+-dependent$ succinate transport system in BLMV that may be shared by the other Krebs cycle intemediates. This transport system seems to be very similar to the luminal transport system for dicarboxylates.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 2004.06a
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• pp.152-154
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• 2004

• Molecules and Cells
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• v.40 no.9
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• pp.643-654
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• 2017

Autophagy is a degradation pathway in eukaryotic cells in which aging proteins and organelles are sequestered into double-membrane vesicles, termed autophagosomes, which fuse with vacuoles to hydrolyze cargo. The key step in autophagy is the formation of autophagosomes, which requires different kinds of vesicles, including COPII vesicles and Atg9-containing vesicles, to transport lipid double-membranes to the phagophore assembly site (PAS). In yeast, the cis-Golgi localized t-SNARE protein Sed5 plays a role in endoplasmic reticulum (ER)-Golgi and intra-Golgi vesicular transport. We report that during autophagy, sed5-1 mutant cells could not properly transport Atg8 to the PAS, resulting in multiple Atg8 dots being dispersed into the cytoplasm. Some dots were trapped in the Golgi apparatus. Sed5 regulates the anterograde trafficking of Atg9-containing vesicles to the PAS by participating in the localization of Atg23 and Atg27 to the Golgi apparatus. Furthermore, we found that overexpression of SFT1 or SFT2 (suppressor of sed5 ts) rescued the autophagy defects in sed5-1 mutant cells. Our data suggest that Sed5 plays a novel role in autophagy, by regulating the formation of Atg9-containing vesicles in the Golgi apparatus, and the genetic interaction between Sft1/2 and Sed5 is essential for autophagy.

• Archives of Pharmacal Research
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• v.9 no.1
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• pp.29-38
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• 1986

The effects of ginseng saponins on the sarcolemmal $Na^{+}$, $K^{+}$-ATPase were compared to gypsophila saponin, sodium dodecylsulfate (SDS), and Triton X-100 to elucidate whether the effects are due to the membrane distruption, using a highly enriched preparation of cardiac sarcolemma prepared from dog ventricular myocardium. About 26% and 29% of vesicles in the preparation, enriched in ouabain-sensitive $Na^{+}$, $K^{+}$-ATP ase, $\beta$-adrenergic and muscarinic receptors are rightside-out and inside-out orientation, respectively. Ginseng saponins (triol>total> diol) inhibited $Na^{+}$, $K^{+}$-ATP ase activity, $Na^{+}$, $K^{+}$-ATPase activity and [$^{3}$H]ouabain binding of sarcolemmal vesicles. However, gypsophila saponin, SDS (0.4$\mu$g/$\mu$g protein) and Triton X-100 (0.6 $\mu$g/$\mu$g protein) caused about 1.35 and 1.40-fold increase in $Na^{+}$, $K^{+}$-ATPase activity and [$^{3}$H] oubain binding, respectively. Especially, the activating effect of gypsophila saponin on membrane Na+, K+ ATPase was detected at gypsophila saponin to sarcolemmal protein ratios as high as 100. Low dose of ginseng saponin (3$\mu$g/$\mu$g protein) decreased the phosphorylation sites and the concentration of ouabain binding sites (Bmax) without affecting the turnover number and affinity for ouabain binding, while gypsophila saponin, SDS(0.4 ug/ug protein), ahd Triton X-100 (0.6$\mu$g/$\mu$g protein) increased the Bmax. The results suggest that ginseng saponins cause a decrease in the number of active sites by interacting directly with $Na^{+}$, $K^{+}$-ATPase before disruption of membrane barriers of sarcolemmal vesicles.

• The Plant Pathology Journal
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• v.29 no.1
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• pp.17-30
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• 2013

Barley stripe mosaic virus (BSMV) induces massive actin filament thickening at the infection front of infected Nicotiana benthamiana leaves. To determine the mechanisms leading to actin remodeling, fluorescent protein fusions of the BSMV triple gene block (TGB) proteins were coexpressed in cells with the actin marker DsRed: Talin. TGB ectopic expression experiments revealed that TGB3 is a major elicitor of filament thickening, that TGB2 resulted in formation of intermediate DsRed:Talin filaments, and that TGB1 alone had no obvious effects on actin filament structure. Latrunculin B (LatB) treat-ments retarded BSMV cell-to-cell movement, disrupted actin filament organization, and dramatically decreased the proportion of paired TGB3 foci appearing at the cell wall (CW). BSMV infection of transgenic plants tagged with GFP-KDEL exhibited membrane proliferation and vesicle formation that were especially evident around the nucleus. Similar membrane proliferation occurred in plants expressing TGB2 and/or TGB3, and DsRed: Talin fluorescence in these plants colocalized with the ER vesicles. TGB3 also associated with the Golgi apparatus and overlapped with cortical vesicles appearing at the cell periphery. Brefeldin A treatments disrupted Golgi and also altered vesicles at the CW, but failed to interfere with TGB CW localization. Our results indicate that actin cytoskeleton interactions are important in BSMV cell-to-cell movement and for CW localization of TGB3.

• Bulletin of the Korean Chemical Society
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• v.11 no.2
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• pp.131-134
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• 1990

Cytochrome c induces fusion of phosphatidylserine /phosphatidylethanolamine vesicles while apocytochrome c does not have a fusogenic capability despite the fact that the apoprotein binds to the vesicles more extensively. In order to see whether the difference in the fusogenic behavior comes from the topological variation in membrane bound proteins, the holoprotein and apoprotein were labeled with phenylisothiocyanate, a hydrophobic label, in the presence of its hydrophilic analogue p-sulfophenylisothiocyanate. Apocytochrome c was labeled with the hydrophobic probe more extensively than the cytochrome c, indicating that the apoprotein penetrates deeper into the bilayer than cytochrome c does. The translocation experiments of these proteins by trypsin entrapped vesicles further supported this conclusion.

• YAKHAK HOEJI
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• v.38 no.6
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• pp.637-645
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• 1994

The effect of various drugs on the stability of the liposomal membrane of phosphatidylcholine and cholesterol was studied, employing the fluorescence self-quenching method. Calcein was entrapped into the phospholipid small unilamellar vesicles and the leakage of the fluorescence probe was monitored on adding the drug to the system. The results of the experiments showed that phenothiazine derivatives, some potent local anesthetics and surface active agents were very effective in inducing the leakage of calcein from the liposome. The leakage-inducing activity of these drug substances has been ascribed to their surface activity and the perturbation of the liposomal membrane by these substances. On the other hand drug substance with low surface activity or without amphiphilic moieties did not show any effect or only small effect on the leakage of calcein from the liposomes. The effect of lipid concentration on the stability of the liposomes was also investigated to show that the higher concentrations of lipid more drug was required to induce the leakage. The effect of surface charges of vesicles was also studied, and the results showed that the charge on the liposomes enhanced the stability of the liposomes against the leakage-inducing activity of these drug substances.

• Journal of Photoscience
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• v.8 no.3_4
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• pp.87-92
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• 2001

Intramolecular excimer formation 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 investigate the effects of parathyroid hormone (PTH) on the bulk bilayer fluidity of the plasma membrane vesicles isolated from cultured osteoblasts (OB-PMV). In a dose-dependent manner, rat PTH-(1-34) [rPTH-(1-34)] increased the excimer to monomer fluorescence intensity ratio (I'/I) of Py-3-Py and decreased the anisotropy (r) of DPH in OB-PMV. This indicates that PTH increased both the lateral and rotational diffusion of the probes in OB-PMY. Selective quenching of DPH fluorescence by trinitrophenyl groups was utilized to examine the transbilayer fluidity asymmetry of OB-PMV. The anisotropy, limiting anisotropy, and order parameter of DPH in the inner monolayer were 0.024, 0.032, and 0.062 greater than calculated for the outer monolayer of OB-PMY. Selective quenching of DPH fluorescence by trinitrophenyl groups was also utilized to examine the transbilayer effects of PTH on the fluidity of OB-PMV. rPTH-(1-34) had a greater fluidizing effect on the outer monolayer as compared to the inner monolayer of OB-PMV. Thus, it has been proven that PTH exhibits a selective rather than nonselective fluidizing effect within transbilayer domains of OB-PMV.

• The Korean Journal of Pain
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• v.6 no.2
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• pp.237-246
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• 1993

세포막에서 마취제의 작용점을 규명하기 위하여, 마취제의 많은 부분을 차지하는 n-Alkanol을 이용하여, 소의 synaptosomal plasma membrane vesicles(SPMV)에서 n-Alkanol의 침투 정도를 형광 probe를 이용한 형광소광법을 통하여 검색하였다. n-Alkanols는 SPMV 외부 단층(outer monolayer)의 표면에 주로 분포하되 그 탄소수에 비례하여 소수성 부위에 분포되는 양이 증가되는 경향을 나타내었다(1-decanol은 제외). Methanol, Ethanol, 1-propanol, 1-butanol, 1-pentano, 1-hexanol, 1-heptanol, 1-octanol, 1-nonanol 및 1-decanil은 SPMV 외부 단층의 표면(친수성 부위)에 분포되는 것에 비하여 각각 949, 416.8, 214.8, 90.3, 53.7, 15.20, 6.80, 2.00, 1.03 및 2.40 배가 된다는 것을 확인하였다. 1-decanol은 $C_{10}$인데도 불구하고 $C_8$인 1-octanol에 비하여 적은 양이 소수성 부위에 침투 분포한다는 것이 확인되었다.