Single Giant Unilamellar Vesicle Method Reveals Effect of Antimicrobial Peptide Magainin 2 on Membrane Permeability†

Biochemistry ◽  
2005 ◽  
Vol 44 (48) ◽  
pp. 15823-15833 ◽  
Author(s):  
Yukihiro Tamba ◽  
Masahito Yamazaki
Keyword(s):  
Antimicrobial Peptide ◽  
Membrane Permeability ◽  
Giant Unilamellar Vesicle

scholarly journals Exogenous fatty acids alter phospholipid composition, membrane permeability, capacity for biofilm formation, and antimicrobial peptide susceptibility in Klebsiella pneumoniae

2018 ◽  
Vol 8 (2) ◽  
pp. e00635 ◽  
Author(s):  
Chelsea R. Hobby ◽  
Joshua L. Herndon ◽  
Colton A. Morrow ◽  
Rachel E. Peters ◽  
Steven J. K. Symes ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Klebsiella Pneumoniae ◽  
Antimicrobial Peptide ◽  
Membrane Permeability ◽  
Biofilm Formation ◽  
Phospholipid Composition

scholarly journals Effects of the antimicrobial peptide temporin L on cell morphology, membrane permeability and viability of Escherichia coli

2004 ◽  
Vol 380 (3) ◽  
pp. 859-865 ◽  
Author(s):  
Maria Luisa MANGONI ◽  
Niv PAPO ◽  
Donatella BARRA ◽  
Maurizio SIMMACO ◽  
Argante BOZZI ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Escherichia Coli ◽  
Antimicrobial Peptides ◽  
Antimicrobial Peptide ◽  
Membrane Permeability ◽  
Dependent Manner ◽  
Inner Membrane ◽  
Tetrazolium Chloride ◽  
Bacterial Membranes ◽  
Microbial Invasion

Antimicrobial peptides are produced by all organisms in response to microbial invasion and are considered as promising candidates for future antibiotics. There is a wealth of evidence that many of them interact and increase the permeability of bacterial membranes as part of their killing mechanism. However, it is not clear whether this is the lethal step. To address this issue, we studied the interaction of the antimicrobial peptide temporin L with Escherichia coli by using fluorescence, confocal and electron microscopy. The peptide previously isolated from skin secretions of the frog Rana temporaria has the sequence FVQWFSKFLGRIL-NH2. With regard to fluorescence microscopy, we applied, for the first time, a triple-staining method based on the fluorochromes 5-cyano-2,3-ditolyl tetrazolium chloride, 4´,6-diamidino-2-phenylindole and FITC. This technique enabled us to identify, in the same sample, both living and total cells, as well as bacteria with altered membrane permeability. These results reveal that temporin L increases the permeability of the bacterial inner membrane in a dose-dependent manner without destroying the cell's integrity. At low peptide concentrations, the inner membrane becomes permeable to small molecules but does not allow the killing of bacteria. However, at high peptide concentrations, larger molecules, but not DNA, leak out, which results in cell death. Very interestingly, in contrast with many antimicrobial peptides, temporin L does not lyse E. coli cells but rather forms ghost-like bacteria, as observed by scanning and transmission electron microscopy. Besides shedding light on the mode of action of temporin L and possibly that of other antimicrobial peptides, the present study demonstrates the advantage of using the triple-fluorescence approach combined with microscopical techniques to explore the mechanism of membrane-active peptides in general.

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.

Synthetic marine guanidines are effective antileishmanial compounds by altering the plasma membrane permeability

Planta Medica ◽  
2014 ◽  
Vol 80 (16) ◽  
Author(s):  
AG Tempone ◽  
LF Martins ◽  
EG Pinto ◽  
JT Mesquita ◽  
EL Bennett ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Membrane Permeability ◽  
Plasma Membrane Permeability
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