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

• Applied Microscopy
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• v.23 no.1
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• pp.1-14
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• 1993

The present study was carried out to analyze the evidence of membrane recycling, and the regulation of cellular transport by dynamic changes in apical membrane area that functionally interacts with the number of cytoplasmic vesicles. Under scanning electron micrographs, turtle bladder mucosa contain three main type of cells; granular cells and carbonic anhydrase (CA)-rich cells, deviding into a and b type of epithelial cell. The granular cell is the majority cell type of the mucosa comprising 80% of the total cell number. The remaining 20% of the cells are characteristically rich in carbonic anhydrase. Uptake of HRP was detected in the most vacuoles or tubulovesicles in both type of CA-rich cells in the turtle bladder, indicating that the part of plasma membrane was internalized in the apical cytoplasmic vacuoles. It seems quite likely that CA-rich cells possess intracellular vesicles carrying proton pumps which are recycling back to the apical plasma membrane. In turtle bladder, the granular cells actively secrete large quantities of mucin and other proteins by an exocytotic mechanism in an apparently constitutive fashion. The possibility that bladder epithelial cells secrete mucin via a regulated secretory pathway has not been rigorously examined and much is still to be determined about these issues from this cell type.

• Journal of Photoscience
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• v.3 no.1
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• pp.33-38
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• 1996

The effect of vesicular L-$\alpha$-phosphatidylcholine on the rate of formation of all-trans-N-retinylidene-n-butylamine (3) and on the regeneration kinetics of bacteriorhodopsin pigment from retinal and bacterio-opsin have been studied. An estimate of the relative positions of retinal and n-butylamine in the vesicles has been made by fluoresence quenching experiments. Partition coefficient of retinal and microviscosity of the retinal-binding region have also been determined. The results are discussed in terms of the nature of chemical interaction between retinal and amine in a lipid environment.

• Molecules and Cells
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• v.41 no.1
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• pp.50-54
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• 2018

Atg5 and Atg7 have long been considered as essential molecules for autophagy. However, we found that cells lacking these molecules still form autophagic vacuoles and perform autophagic protein degradation when subjected to certain stressors. During this unconventional autophagy pathway, autophagosomes appeared to be generated in a Rab9-dependent manner by the fusion of vesicles derived from the trans-Golgi and late endosomes. Therefore, mammalian autophagy can occur via at least two different pathways; the Atg5/Atg7-dependent conventional pathway and an Atg5/Atg7-independent alternative pathway.

• Journal of Microbiology and Biotechnology
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• v.28 no.10
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• pp.1769-1769
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• 2018

• Proceedings of the Korean Biophysical Society Conference
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• 1999.06a
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• pp.45-45
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• 1999

Cytochrome c (cyt c) binds to acidic membranes at low ionic strength. Replacement of Lys-72 or Lys-87 by Glu reduced the binding affinity of cyt c toward large unilamellar vesicles (LUV) in liquid crystalline phase. The differences were smaller for LUV in gel phase. A fraction of bound cyt c was non-electrostatically associated.(omitted)

• Bulletin of the Korean Chemical Society
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• v.10 no.1
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• pp.69-71
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• 1989

Effects of SDS and temperature on the conformational changes of bacteriorhodopsin were studied using a, b, c bands of bacteriorhodopsin. In the SDS denaturation, bacteriorhodopsin in purple membrane was more labile than bacteriorhodopsin reconstituted into PC vesicles. These rather interesting results may be understood by effective SDS concentration in lipid layer.

• Archives of Pharmacal Research
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• v.15 no.3
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• pp.196-203
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• 1992

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 barbiturates on the fluidity of model membranes of phosphatidycholine (SPMVPC), phosphatidylserine (SPMVPS), and phosphatidylinositol (SPMVPI) fractions of synaptosomal plasma membrane vesicles (SPMV) isolated from bovine cerebral cortex. In a dose-dependent manner, barbiturates decreased the excimer to monomer fluorescence intensity ratio (I'/I) of Py-3-Py and increased the anisotropy(r), rotational relaxation time (P), limiting anisotropy $(r_infty)$, and order parameter (S) of DPH in SPMVPC, SPMVPS and SPMVPI. This indicates that barbiturates decreased both the lateral and rotational diffusion of the probes in SPMVPC, SPMVPS and SPMVPI. The relative potencies of barbiturates in ordering the membranes were in the order: pentobarbital > hexobarbital > amobarbital > phenobarbital. This order correlates well with the anesthetic potencies of barbiturates and the potencies for enhancement of $\gamma$-aminobutyric acid-stimulated chloride uptake. Thus, it is strongly suggested that a close relationship might exist between the membrane ordering effects of barbiturates and the chloride fluxes across SPMV.

• Animal cells and systems
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• v.4 no.2
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• pp.165-171
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• 2000

Ubiquitinated proteins in lysosomes were characterized by using two monoclonal antibodies (mAbs): LYS8-1, a mAb to lysosomal proteins, and NYA124, a mAb to ubiquitin. LYS8-1 stained lysosome-like vesicles in immunofluorescence microscopy of Amoeba proteus and Acanthamoeba castellanii. In immunoblotting, LYS8-1's antigens (LYS proteins) were detected as 68-kDa and 77-kDa proteins in A. proteus, and as 30-kDa and 39-kDa proteins in A. castellanii. In immunoprecipitation of A. castellanii, at least four distinct LYS proteins, LVS35p, LyS39p, LyS42p, and LYS46p, were detected and accumulated upon inhibition of lysosome functions but not upon that of 26S proteasome functions. They were all found to be ubiquitinated, and were recovered in the lysosome fractions in subcellular fractionation experiments. In chemical fractionation analyses, LYS35p and LYS39p were demonstrated to be peripherally associated with lysosome membrane, while LYS42p and LYS46p tightly bound to the membrane. These results suggest that the LYS proteins become associated to lysosomal membrane upon ubiquitination.

• Journal of Microbiology and Biotechnology
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• v.25 no.2
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• pp.162-173
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• 2015

The cellular fatty acid composition is important for metabolic plasticity in Rhodobacter sphaeroides. We explored the effects of changing the cellular ratio of unsaturated fatty acids (UFAs) to saturated fatty acids (SFAs) in R. sphaeroides by overexpressing several key fatty acid biosynthetic enzymes through the use of expression plasmid pRK415. Bacteria containing the plasmid pRKfabI₁ with the fabI₁ gene that encodes enoyl-acyl carrier protein (ACP) reductase showed a reduction in the cellular UFA to SFA ratio from 4 (80% UFA) to 2 (65% UFA) and had decreased membrane fluidity and reduced cell growth. Additionally, the ratio of UFA to SFA of the chromatophore vesicles from pRKfabI₁-containing cells was similarly lowered, and the cell had decreased levels of light-harvesting complexes, but no change in intracytoplasmic membrane (ICM) content or photosynthetic (PS) gene expression. Both inhibition of enoyl-ACP reductase with diazaborine and addition of exogenous UFA restored membrane fluidity, cell growth, and the UFA to SFA ratio to wild-type levels in this strain. R. sphaeroides containing the pRKfabB plasmid with the fabB gene that encodes the enzyme β-ketoacyl-ACP synthase I exhibited an increased UFA to SFA ratio from 4 (80% UFA) to 9 (90% UFA), but showed no change in membrane fluidity or growth rate relative to control cells. Thus, membrane fluidity in R. sphaeroides remains fairly unchanged when membrane UFA levels are between 80% and 90%, whereas membrane fluidity, cell growth, and cellular composition are affected when UFA levels are below 80%.