Pore formation by alamethicin in planar bilayers below lipid phase transition temperature

1981 ◽  
Vol 7 (4) ◽  
pp. 300-300
Author(s):  
W. Hanke ◽  
H. Eibl ◽  
G. Boheim
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Phase Transition Temperature ◽  
Pore Formation ◽  
Lipid Phase ◽  
Lipid Phase Transition ◽  
Planar Bilayers

scholarly journals Protein-mediated lipid transfer. The effects of lipid-phase transition and of charged lipids

1983 ◽  
Vol 213 (1) ◽  
pp. 21-24 ◽  
Author(s):  
Y H Xü ◽  
K Gietzen ◽  
H J Galla ◽  
E Sackmann
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Phosphatidic Acid ◽  
Phase Transition Temperature ◽  
Fluorescence Polarization ◽  
Exchange Process ◽  
Lipid Phase ◽  
Lipid Transfer ◽  
Lipid Phase Transition ◽  
Polarization Measurements

The protein-mediated phospholipid exchange between small unilamellar vesicles was investigated by fluorescence polarization measurements with diphenylhexatriene as optical probe. Thermotropic phase-transition measurements were taken after mixing two vesicle preparations of distinct and different phase-transition temperatures or having different states of charge. From the heights of each phase-transition step, we were able to follow the lipid-exchange process in the presence, as well as in the absence (natural exchange), of so-called transfer protein isolated from beef liver. A strong enhancement of the lipid transfer was observed at the corresponding lipid-phase-transition temperature, which is explained by the presence of fluctuating fluid and ordered domains co-existing at the lipid-phase-transition temperature. A unidirectional lipid transfer of the neutral component was observed between negatively charged phosphatidic acid and neutral phosphatidylcholine vesicles. Fluorescence polarization measurements showed the disappearance of the phosphatidylcholine phase transition, whereas the phosphatidic acid phase transition broadened and its phase transition temperature became lower.

scholarly journals Stabilization of model membranes during drying by compatible solutes involved in the stress tolerance of plants and microorganisms

2004 ◽  
Vol 383 (2) ◽  
pp. 277-283 ◽  
Author(s):  
Dirk K. HINCHA ◽  
Martin HAGEMANN
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Transition Temperature ◽  
Phase Transition Temperature ◽  
Membrane Lipids ◽  
Compatible Solutes ◽  
Stress Conditions ◽  
Lipid Phase ◽  
Cellular Protection ◽  
Solute Leakage

Many organisms accumulate compatible solutes under environmental stress conditions. Cyanobacteria accumulate compatible solutes in response to increased external salinity, with tolerance increasing from Suc (sucrose) or trehalose to 2-O-(α-D-glucopyranosyl)-glycerol and glycinebetaine accumulating species. It is not clear how these different solutes influence salt tolerance. One possible explanation may be a differential ability of these solutes to stabilize membranes under stress conditions. We therefore performed drying experiments with liposomes in the presence of compatible solutes. Suc, trehalose and sorbitol protected liposomes from leakage of a soluble marker and from membrane fusion during drying and rehydration. 2-O-(α-D-glucopyranosyl)-glycerol was less effective and glycinebetaine showed hardly any effect. In combination with Suc, the latter two solutes showed improved protection. Lipid-phase transitions are known to contribute to solute leakage from liposomes. We determined phase transitions in dry membranes in the absence or presence of the solutes, using Fourier-transform infrared spectroscopy. The ability of the solutes to decrease the phase transition temperature corresponded closely to their ability to protect the liposomes against solute leakage. All solutes interacted with the phosphate in the lipid headgroups. The magnitude of the shift in the asymmetric P=O stretching vibration correlated closely with the lipid-phase transition temperature. This indicates that the degree of membrane protection afforded by the solutes is mainly determined by their ability to interact with the membrane lipids. However, this is not a determinant of cellular protection against salt stress, as the solutes show a reverse order when ranked with regard to protection against these stresses.

Emerging advances in cationic liposomal cancer nanovaccines: opportunities and challenges

Immunotherapy ◽  
2021 ◽  
Author(s):  
Mohammad Z Ahmad ◽  
Javed Ahmad ◽  
Mohammed Y Alasmary ◽  
Basel A Abdel-Wahab ◽  
Musarrat H Warsi ◽  
...  
Keyword(s):  
Phase Transition ◽  
Immune Response ◽  
Transition Temperature ◽  
Cancer Immunotherapy ◽  
Cancer Therapeutics ◽  
Physicochemical Characteristics ◽  
Cationic Liposomes ◽  
Lipid Phase ◽  
Lipid Phase Transition ◽  
Delivery Platform

Advancements in the field of cancer therapeutics have witnessed a recent surge in the use of liposomes. The physicochemical characteristics of the liposomes and their components, including the lipid phase transition temperature, vesicular size and size distribution, surface properties, and route of administration, play a significant role in the modulation of the immune response as an adjuvant and for loaded antigen (Ag). Cationic liposomes, concerning their potential ability to amplify the immunogenicity of the loaded Ag/adjuvant, have received enormous interest as a promising vaccine delivery platform for cancer immunotherapy. In the present review, the physicochemical considerations for the development of Ag/adjuvant-loaded liposomes and the cationic liposomes’ effectiveness for promoting cancer immunotherapy have been summarized.

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