• Journal of Life Science
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• v.2 no.2
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• pp.97-107
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• 1992

Strichartz and Richie have suggested that the mechanism of sodium donductance block of local anesthetics involves their interaction with a specific binding site within the sodium channel. However, there is evidence that local anesthetics can interact electrostatically with membrane proteins as well as membrane lipids. Whether or not all actions of local anesthetics are mediated by common site remains unclear. Thus, it can not be ruled out that local anesthetics concurrently interact with neuronal membrane lipids since sodium channels were found to be tightly associated with membrane lipids through covalent or noncovalent bonds. In summary, it is strongly postulated that local anesthetics, in addition to their direct interaction with sodium channels, concurrently interact with membrane lipids, fluidize the membrane, and thus induce conformational changes of sodium channels, which are known to be tightly associated with membrane lipids.

• Membrane and Water Treatment
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• v.5 no.3
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• pp.171-182
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• 2014

Organic compounds are adsorbed on RO/NF membranes, and the adsorption may influence the rejection of organic compounds by the membranes. Because almost RO/NF membranes are composite membranes, the results obtained by adsorption experiment with using membrane pieces are unable to avoid the influence by the support membrane. In this work, the interaction between membrane polymer and organic solutes was examined by an inverse HPLC methodology. Poly (m-phenylenetrimesoylate), the constituent of skin layer of RO/NF membranes, was coated on silica gel particles and used as a stationary phase for HPLC. When water was used as a mobile phase, almost hydrophilic aliphatic compounds were not effectively adsorbed on the stationary phase, although hydrophobic compounds were slightly adsorbed. The results indicated that the hydrophilic aliphatic compounds are useful probe solutes to examine the molecular sieving effect of a membrane. When water was used as a mobile phase, the aromatic compounds were strongly retained, and therefore $CH_3CN/H_2O$ (30/70) was used as a mobile phase. It was revealed that the adsorption of aromatic compounds was controlled by stacking between solute and polymer and was hindered by non-planar structure and substituents.

• Molecules and Cells
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• v.21 no.3
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• pp.428-435
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• 2006

Specific interaction of the epsin N-terminal homology(ENTH) domain with the plasma membrane appears to bridge other related proteins to the specific regions of the membrane that are invaginated to form endocytic vesicles. An additional $\alpha$-helix, referred to as helix 0 (H0), is formed in the presence of the soluble ligand inositol-1,4,5-trisphosphate [$Ins(1,4,5)P_3$] at the N terminus of the ENTH domain (amino acid residues 3-15). The ENTH domain alone and full-length epsin cause tubulation of liposomes made of brain lipids. Thus, it is believed that H0 is membrane-inserted when it is coordinated with the phospholipid phosphatidylinositol-4,5-bisphosphate [$PtdIns(4,5)P_2$], resulting in membrane deformation as well as recruitment of accessory factors to the membrane. However, formation of H0 in a real biological membrane has not been demonstrated. In the present study, the membrane structure of H0 was determined by measurement of electron paramagnetic resonance (EPR) nitroxide accessibility. H0 was located at the phosphate head-group region of the membrane. Moreover, EPR line-shape analysis indicated that no pre-formed H0-like structure were present on normal acidic membranes. $PtdIns(4,5)P_2$ was necessary and sufficient for interaction of the H0 region with the membrane. H0 was stable only in the membrane. In conclusion, the H0 region of the ENTH domain has an intrinsic ability to form H0 in a $PtdIns(4,5)P_2$-containing membrane, perhaps functioning as a sensor of membrane patches enriched with $PtdIns(4,5)P_2$ that will initiate curvature to form endocytic vesicles.

• Journal of Nutrition and Health
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• v.30 no.6
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• pp.658-668
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• 1997

Path of a small hydrophobic molecule through the aqueous cytoplasma is not linear. Partition may favor membrane binding by several orders of magnitude : thus significant membrane association will markedly decrease the cytosolic transport rate. The presence of high concentration of soluble binding proteins for these hydrophobic molecules would compete with membrane association and thereby increase transport rate. For long chain fatty acid molecules, a family of cytosolic binding proteins collectively known as the fatty acid binding proteins(FABP), are thought to act as intracellular transport proteins. This paper examines the mechanism of transfer of fluorescent antyroyloxy-labeled fatty acids(AOFA) from purified FABPs to phosholipid membranes. With the exception of the liver FABP, AOFA is transferred from FABP by collisional interaction of the protein with a acceptor membrane. The rate of transfer increased markedly when membranes contain anionic phospholipids. This suggests that positively charged residues on the surface of the FABP may interact with the membranes. Neutralization of the surface lysine residues of adipocyte FABP decreased fatty acid transfer rate, and transfer was found to proceed via aqueous diffusion rather than collisional interaction. Site specific mutagenesis has further shown that the helix-turn-helix domain of the FABP is critical for interaction with anionic acceptor membranes. Thus cytosolic FABP may function in intracellular transport of fatty acid to decrease their membranes association as well as to target fatty acid to specific subcellular sites of utilization.

• The Korean Journal of Physiology
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• v.30 no.2
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• pp.249-256
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• 1996

The effect of probenecid on the transport of tetraethylammonium (TEA) was studied in renal cortical slices and isolated membrane vesicles to investigate the interaction of organic anion with the organic cation transport system in proximal tubule. Probenecid reversibly inhibited TEA uptake by renal cortical slices in a dose-dependent manner over the concentration range of 1 and 5 mM. The efflux of TEA was not affected by the presence of 3 mM probenecid. Kinetic analysis indicated that probenecid decreased Vmax without significant change in Km. Probenecid inhibited significantly tissue oxygen consumption at concentrations of 3 and 5 mM. However, probenecid did not significantly reduce TEA uptake in brush border and basolateral membrane vesicles prepared from renal cortex even at a concentration as high as 10 mM. These results indicate that probenecid reduces TEA uptake in cortical slices by inhibiting tissue metabolism rather than by an interaction with the organic ration transporter.

• Biomolecules & Therapeutics
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• v.4 no.4
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• pp.398-401
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• 1996

The glucose transporters found in the plasma membrane of all animal cells are known to have 12 putative transmembrane domains. Among 7 cytoplasmic loops, the fourth loop is the largest one. Since previous studies showed that cofilin, an actin-modulating protein, was found to interact with the largest cytoplasmic loop of (Na, K)ATPase, we tested if cofilin interacts with the largest cytoplasmic loop of Glut4. We demonstrated by the two-hybrid system that the largest cytoplasmic loop of Glut4 did not show any interaction with cofilin, suggesting that cofilin is not required for the membrane targeting process of other membrane proteins but only for a P-type ATPase.

• Proceedings of the Korea Water Resources Association Conference
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• 2001.05b
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• pp.1133-1138
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• 2001

The focus of this paper is on the numerical investigation of obliquely incident wane interactions with a system composed of full submerged and floating dual buoy/vertical-flexible-membrane breakwaters placed in parallel with spacing. The fully submerged systems allow surface and bottom clearances to enable wave transmission over and under the system. The problem is formulated based on the two-dimensional multi-domain hydro-elastic linear wave-body interaction theory. The hydrodynamic interaction of oblique incident waves with the combination of the rigid and flexible bodies was solved by the distribution of the simple sources (modified Bessel function of fille second kind) tat satisfy the Helmholz governing equation. Using this computer program, the performance of various dual systems varying buoy radiuses and drafts, membrane lengths, clearances. spacing, mooring-lines stiffness, mooring types, water depth, and wave characteristics is thoroughly examined. It is found that the fully submerged and floating dual buoy/membrane breakwaters call, if it is properly tuned to the coming waves, have good performances ill reflecting the obliquely incident waves over a tilde range of wave frequency and headings.

• Wind and Structures
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• v.25 no.5
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• pp.415-432
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• 2017

The nonlinear aerodynamic instability of a tensioned plane orthotropic membrane structure is theoretically investigated in this paper. The interaction governing equation of wind-structure coupling is established by the Von $K\acute{a}rm\acute{a}n's$ large amplitude theory and the D'Alembert's principle. The aerodynamic force is determined by the potential flow theory of fluid mechanics and the thin airfoil theory of aerodynamics. Then the interaction governing equation is transformed into a second order nonlinear differential equation with constant coefficients by the Bubnov-Galerkin method. The critical wind velocity is obtained by judging the stability of the second order nonlinear differential equation. From the analysis of examples, we can conclude that it's of great significance to consider the orthotropy and geometrical nonlinearity to prevent the aerodynamic instability of plane membrane structures; we should comprehensively consider the effects of various factors on the design of plane membrane structures; and the formula of critical wind velocity obtained in this paper provides a more accurate theoretical solution for the aerodynamic stability of the plane membrane structures than the previous studies.

• Architectural research
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• v.11 no.1
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• pp.7-14
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• 2009

In this paper, we take advantage of Wavelet Transform to identify damping ratios of membrane structures under wind action. Due to the lightweight and flexibility of membrane structures, they are very sensitive to the wind load, and show a type of fluid-structure interaction phenomenon simultaneously. In this study, we firstly obtain the responses of an air-supported membrane structure by ADINA with the consideration of this characteristic, and then conduct Wavelet Transform on these responses. Based on the Wavelet Transform, damping ratios could be obtained from the slope of Wavelet Transform in a semi-logarithmic scale at a certain dilation coefficient. According to this principle, damping ratios could eventually be obtained. There are two numerical examples in this study. The first one is a simulated signal, which is used to verify the accuracy of the Wavelet Transform method. The second one is an air-supported membrane structure under wind action, damping ratios obtained from this method is about 0.05~0.09. The Wavelet Transform method could be regarded as a very good method for the the damping analysis, especially for the large spatial structures whose natural frequencies are closely spaced.

• Bulletin of the Korean Chemical Society
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• v.34 no.1
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• pp.231-236
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• 2013

Some cytotoxicity studies for the interpretation of the interaction between nanoparticles and cells are non-mechanistic and time-consuming. Therefore, non-biological screening methods, which are faster and simpler than in-vivo and in-vitro methods, are required as alternatives to current cytotoxicity tests. Here, we proposed a simple screening method for the analysis of the interaction between several AgNPs (bare-, citrate-, and polyvinylpyrrolidone-coating) and dye-containing vesicles acting as a biomimetic cell-membrane. The interaction between AgNPs and vesicles could be evaluated readily by UV-vis spectra. Absorbance deviation in UV-vis spectra revealed a large attraction between neighboring particles and vesicles. This was confirmed by (Derjagin, Landau, Verwey, and Overbeek) theory and DMF (dark-field microscopy) analysis. This proposed method might be useful for analyzing the cytotoxicity of nanoparticles with cell-membranes instead of in vitro or in vivo cytotoxicity tests.