Methyl to trifluoromethyl substitution as a strategy to increase membrane permeability of short peptides

2021 ◽  
Author(s):  
Takahiro Ono ◽  
Kohsuke Aikawa ◽  
Takashi Okazoe ◽  
Jumpei Morimoto ◽  
Shinsuke Sando
Keyword(s):  
Membrane Permeability ◽  
Short Peptides ◽  
Increase Membrane Permeability

Here, we investigated the effect of CH3 to CF3 substitution on membrane permeability of peptides. We synthesized a series of peptides with CF3 groups and corresponding nonfluorinated peptides and measured...

Effects of sulphur dioxide and ozone, singly or in combination, on membrane permeability

1980 ◽  
Vol 58 (4) ◽  
pp. 451-457 ◽  
Author(s):  
D. W. Beckerson ◽  
G. Hofstra
Keyword(s):  
Electrical Conductivity ◽  
Membrane Permeability ◽  
Sulphur Dioxide ◽  
Leaf Surface ◽  
Visible Injury ◽  
Solute Leakage ◽  
White Bean ◽  
Increase Membrane Permeability ◽  
Species Responses

The effects of 0.15 ppm sulphur dioxide and (or) 0.15 ppm ozone on membrane permeability, measured by electrical conductivity of solute leakage, were determined for soybean, white bean, cucumber, and radish. Solute leakage increased significantly prior to visible injury for soybean and white bean exposed to 0.15 ppm ozone alone. This results in water-soaked lesions on the upper leaf surface prior to visible coloured necrotic lesions and is representative of a "leaky" plasmalemma. The sulphur dioxide – ozone mixture did not increase solute leakage above that of the control for white bean and soybean. Therefore, the presence of sulphur dioxide, in combination with ozone, attenuates or reduces the effects of ozone on increasing membrane permeability of white bean and soybean. Ozone alone did not affect membrane permeability in cucumber and radish. The sulphur dioxide – ozone mixture, which produced more injury than ozone alone, did increase membrane permeability temporarily for radish and cucumber but this occurred only after visible injury symptoms appeared. Overall, the effects of the pollutants singly or in combination on membrane permeability appear to offer an explanation of differences in species responses.

scholarly journals Quercetin Induces Lipid Domain-Dependent Permeability

2021 ◽  
Author(s):  
Natalia Slade ◽  
Danubia Batista Martins ◽  
Marcia P. dos Santos Cabrera
Keyword(s):  
Liquid Phase ◽  
Membrane Permeability ◽  
Model Membranes ◽  
The Other ◽  
Lipid Domains ◽  
Lipid Domain ◽  
Homogeneous Systems ◽  
Membrane Rigidity ◽  
Increase Membrane Permeability ◽  
Shape And Size

In this work, we present our results on quercetin interaction with distinct model membranes exploring the importance of lipid phases, ld, ld/lo and ld+lo+so, to the action of this flavonoid in bilayers and possibly contributing to clarifying some controversial aspects related to quercetin multiple activities. We found out that quercetin is able to increase membrane permeability in a manner dependent on the presence and characteristics of lipid domains. In the presence of sphingomyelin, we found the greatest increase in mean membrane permeability (at least 10 times higher than the other lipid compositions). We also observed the presence of micrometric domains whose shape and size were disturbed by the action of quercetin. The presence of cholesterol increased membrane rigidity. This effect was enhanced with the presence of quercetin, but for chol-sphingomyelin combination, the bilayers became more flaccid at low quercetin/lipid proportions (< 1/5) and moderately rigid at proportions of the 1/1 order. The affinity parameters were higher for the most homogeneous systems and with larger areas and extensions of disordered liquid phase than for those systems of higher heterogeneity.

scholarly journals An improved method for tyrosine hydroxylase immunolabeling of catecholamine cells in whole mounted rat retina.

1986 ◽  
Vol 34 (6) ◽  
pp. 743-747 ◽  
Author(s):  
C Versaux-Botteri ◽  
J Nguyen-Legros
Keyword(s):  
Tyrosine Hydroxylase ◽  
Membrane Permeability ◽  
Efficient Method ◽  
Primary Antibody ◽  
Improved Method ◽  
Rat Retina ◽  
Good Penetration ◽  
Increase Membrane Permeability

We developed a rapid and efficient method to achieve good penetration of anti-tyrosine hydroxylase (TH) antiserum into whole mounted rat retinas. The retinas were defatted before incubation in the primary antibody. This operation was thought to increase membrane permeability, facilitating penetration of antibodies. As a result, all TH-positive cells in the entire retina were labeled. Thus, it becomes possible to study the morphology, the distribution, and the counting of TH immunoreactive cells in whole retinas.

scholarly journals Quercetin Induces Lipid Domain-Dependent Permeability

2021 ◽  
Author(s):  
Natalia Slade ◽  
Danubia Batista Martins ◽  
Marcia P. dos Santos Cabrera
Keyword(s):  
Liquid Phase ◽  
Membrane Permeability ◽  
Model Membranes ◽  
The Other ◽  
Lipid Domains ◽  
Lipid Domain ◽  
Homogeneous Systems ◽  
Membrane Rigidity ◽  
Increase Membrane Permeability ◽  
Shape And Size

In this work, we present our results on quercetin interaction with distinct model membranes exploring the importance of lipid phases, ld, ld/lo and ld+lo+so, to the action of this flavonoid in bilayers and possibly contributing to clarifying some controversial aspects related to quercetin multiple activities. We found out that quercetin is able to increase membrane permeability in a manner dependent on the presence and characteristics of lipid domains. In the presence of sphingomyelin, we found the greatest increase in mean membrane permeability (at least 10 times higher than the other lipid compositions). We also observed the presence of micrometric domains whose shape and size were disturbed by the action of quercetin. The presence of cholesterol increased membrane rigidity. This effect was enhanced with the presence of quercetin, but for chol-sphingomyelin combination, the bilayers became more flaccid at low quercetin/lipid proportions (< 1/5) and moderately rigid at proportions of the 1/1 order. The affinity parameters were higher for the most homogeneous systems and with larger areas and extensions of disordered liquid phase than for those systems of higher heterogeneity.

scholarly journals Quercetin Induces Lipid Domain-Dependent Permeability

2021 ◽  
Author(s):  
Natalia Slade ◽  
Marcia P. dos Santos Cabrera ◽  
Danubia Batista Martins
Keyword(s):  
Liquid Phase ◽  
Membrane Permeability ◽  
Model Membranes ◽  
The Other ◽  
Lipid Domains ◽  
Lipid Domain ◽  
Homogeneous Systems ◽  
Membrane Rigidity ◽  
Increase Membrane Permeability ◽  
Shape And Size

In this work, we present our results on quercetin interaction with distinct model membranes exploring the importance of lipid phases, ld, ld/lo and ld+lo+so, to the action of this flavonoid in bilayers and possibly contributing to clarifying some controversial aspects related to quercetin multiple activities. We found out that quercetin is able to increase membrane permeability in a manner dependent on the presence and characteristics of lipid domains. In the presence of sphingomyelin, we found the greatest increase in mean membrane permeability (at least 10 times higher than the other lipid compositions). We also observed the presence of micrometric domains whose shape and size were disturbed by the action of quercetin. The presence of cholesterol increased membrane rigidity. This effect was enhanced with the presence of quercetin, but for chol-sphingomyelin combination, the bilayers became more flaccid at low quercetin/lipid proportions (< 1/5) and moderately rigid at proportions of the 1/1 order. The affinity parameters were higher for the most homogeneous systems and with larger areas and extensions of disordered liquid phase than for those systems of higher heterogeneity.

Initial Polymerization Sites Indicated During Mitochondrial Oxidation of Diaminobenzidine after Toluene Treatment

1977 ◽  
Vol 35 ◽  
pp. 408-409
Author(s):  
W. A. Shannon ◽  
M. A. Matlib
Keyword(s):  
Membrane Permeability ◽  
Cytochrome Oxidase ◽  
Rat Liver ◽  
Precise Definition ◽  
Cytochemical Localization ◽  
Oxidative Reaction ◽  
Mitochondrial Oxidation ◽  
Definition Of ◽  
Exogenous Substrates

Numerous studies have dealt with the cytochemical localization of cytochrome oxidase via cytochrome c. More recent studies have dealt with indicating initial foci of this reaction by altering incubation pH (1) or postosmication procedure (2,3). The following study is an attempt to locate such foci by altering membrane permeability. It is thought that such alterations within the limits of maintaining morphological integrity of the membranes will ease the entry of exogenous substrates resulting in a much quicker oxidation and subsequently a more precise definition of the oxidative reaction.The diaminobenzidine (DAB) method of Seligman et al. (4) was used. Minced pieces of rat liver were incubated for 1 hr following toluene treatment (5,6). Experimental variations consisted of incubating fixed or unfixed tissues treated with toluene and unfixed tissues treated with toluene and subsequently fixed.

Sarcolemmal permeability changes during early myocardial anoxia

1978 ◽  
Vol 36 (2) ◽  
pp. 642-643
Author(s):  
M. Ashraf ◽  
L. Landa ◽  
L. Nimmo ◽  
C. M. Bloor
Keyword(s):  
Cell Membrane ◽  
Membrane Permeability ◽  
Coronary Artery Occlusion ◽  
Artery Occlusion ◽  
Cell Membrane Permeability ◽  
Enzyme Release ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Sarcolemmal Permeability ◽  
Membrane Changes

Following coronary artery occlusion, the myocardial cells lose intracellular enzymes that appear in the serum 3 hrs later. By this time the cells in the ischemic zone have already undergone irreversible changes, and the cell membrane permeability is variably altered in the ischemic cells. At certain stages or intervals the cell membrane changes, allowing release of cytoplasmic enzymes. To correlate the changes in cell membrane permeability with the enzyme release, we used colloidal lanthanum (La+++) as a histological permeability marker in the isolated perfused hearts. The hearts removed from sprague-Dawley rats were perfused with standard Krebs-Henseleit medium gassed with 95% O2 + 5% CO2. The hypoxic medium contained mannitol instead of dextrose and was bubbled with 95% N2 + 5% CO2. The final osmolarity of the medium was 295 M osmol, pH 7. 4.

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