Membrane damage at low hydrations: Lipid phase behaviour and the effect of solutes

2008 ◽  
pp. 187-187
Author(s):  
G. Bryant ◽  
J. Wolfe
Keyword(s):  
Membrane Damage ◽  
Phase Behaviour ◽  
Lipid Phase

scholarly journals Lipid phase behaviour under steady state conditions

2013 ◽  
Vol 161 ◽  
pp. 151-166 ◽  
Author(s):  
Christoffer Åberg ◽  
Emma Sparr ◽  
Håkan Wennerström
Keyword(s):  
Steady State ◽  
Phase Behaviour ◽  
Lipid Phase

Differential scanning calorimetry and X-ray diffraction studies of a series of synthetic β-D-galactosyl diacylglycerols

1991 ◽  
Vol 69 (12) ◽  
pp. 863-867 ◽  
Author(s):  
D. A. Mannock ◽  
R. N. McElhaney
Keyword(s):  
Phase Transition ◽  
Differential Scanning Calorimetry ◽  
Phase Behaviour ◽  
Lipid Phase ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Phase Transition Temperatures ◽  
Bonding Properties ◽  
Lower Temperature

We have investigated the physical properties of a homologous series of synthetic, saturated 1,2-di-O-acyl-3-O-(β-D-galactopyranosyl)-sn-glycerols using calorimetry and X-ray diffraction. Unannealed aqueous dispersions of these compounds exhibit a lower temperature, moderately energetic, chain-melting (Lβ/Lα phase transition and a higher temperature, weakly energetic, bilayer/nonbilayer phase transition. On annealing below the Lβ/Lα phase transition, the Lβ phase converts to an LC phase, which may undergo a highly energetic LC/Lα or LC/HII phase transition at very high temperatures on reheating. The temperatures of these phase transitions are higher than those seen in the corresponding α- and β-D-glucosyl diacylglycerols. However, the Lβ/Lα and bilayer/nonbilayer phase transition temperatures of the β-D-galactosyl diacylglycerols are lower than those of the corresponding diacyl phosphatidylethanolamines. These observations are discussed in terms of the hydration and hydrogen bonding properties of their respective headgroups.Key words: differential scanning calorimetry, low-angle x-ray diffraction, glycolipids, galactolipids, lipid phase behaviour.

Fluorescent probe partitioning in giant unilamellar vesicles of ‘lipid raft’ mixtures

2010 ◽  
Vol 430 (3) ◽  
pp. 415-423 ◽  
Author(s):  
Janos Juhasz ◽  
James H. Davis ◽  
Frances J. Sharom
Keyword(s):  
Fluorescent Probe ◽  
Lipid Bilayer ◽  
Fluorescent Probes ◽  
Phase Behaviour ◽  
Model Systems ◽  
Fluorescence Probes ◽  
Lipid Phase ◽  
Giant Unilamellar Vesicles ◽  
Unilamellar Vesicles ◽  
Lipid Mixture

Direct visualization of raft-like lo (liquid-ordered) domains in model systems and cells using microscopic techniques requires fluorescence probes with known partitioning preference for one of the phases present. However, fluorescent probes may display dissimilar partitioning preferences in different lipid sys-tems and can also affect the phase behaviour of the host lipid bilayer. Therefore a detailed understanding of the behaviour of fluorescent probes in defined lipid bilayer systems with known phase behaviour is essential before they can be used for identifying domain phase states. Using giant unilamellar vesicles composed of the ternary lipid mixture DOPC (1,2-dioleoyl-sn-glycero-3-phosphocholine)/DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine)/cholesterol, for which the phase behaviour is known, we examined nine commonly used fluorescent probes using confocal fluorescence microscopy. The partitioning preference of each probe was assigned either on the basis of quantification of the domain area fractions or by using a well-characterized ld (liquid-disordered)-phase marker. Fluorescent probes were examined both individually and using dual or triple labelling approaches. Most of the probes partitioned individually into the ld phase, whereas only NAP (naphtho[2,3-a]pyrene) and NBD-DPPE [1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine-N-(7-nitro-2-1,3-benzoxadiazol-4-yl] preferred the lo phase. We found that Rh-DPPE (Lissamine™ rhodamine B–1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine) increased the miscibility transition temperature, Tmix. Interestingly, the partitioning of DiIC18 (1,1′-dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine perchlorate) was influenced by Bodipy®-PC [2-(4,4-difluoro-5,7-dimethyl-4-bora-3a,4a-diaza-s-indacene-3-pentanoyl)-1-hexa-decanoyl-sn-glycero-3-phosphocholine]. The specific use of each of the fluorescent probes is determined by its photostability, partitioning preference, ability to detect lipid phase separations and induced change in Tmix. We demonstrate the importance of testing a specific fluorescent probe in a given model membrane system, rather than assuming that it labels a particular lipid phase.

Cold-induced lipid phase transitions

1990 ◽  
Vol 326 (1237) ◽  
pp. 555-570 ◽  
Keyword(s):  
Low Temperatures ◽  
Membrane Lipids ◽  
Weak Interactions ◽  
Protective Action ◽  
Biological Membranes ◽  
Membrane Lipid ◽  
Phase Behaviour ◽  
Lipid Phase ◽  
Aqueous Environment ◽  
Factors Affecting

The structural organization of biological membranes is largely determined by the weak interactions existing between their components and between these components and their aqueous environment. These interactions are particularly sensitive to changes in temperature and hydration. The factors influencing membrane lipid phase behaviour are briefly reviewed and used to develop a phase-separation model describing the response of biological membranes to stress. The factors affecting the interaction of cryoprotectants with membrane lipids are explored and their role in the stabilization of membrane organization at low temperatures discussed. It is suggested that the basis of their protective action lies in an ability to preserve the balance of interactions between membrane components at low temperatures at a level similar to that existing under physiological conditions.

scholarly journals Changes in lipid phase behaviour in human myelin during maturation and aging

FEBS Letters ◽  
1983 ◽  
Vol 157 (1) ◽  
pp. 155-158 ◽  
Author(s):  
L.S. Chia ◽  
J.E. Thompson ◽  
M.A. Moscarello
Keyword(s):  
Phase Behaviour ◽  
Lipid Phase

scholarly journals Influence of Dodecyltrimethylammonium Halides on Thermotropic Phase Behaviour of Phosphatidylcholine/Cholesterol Bilayers

2000 ◽  
Vol 55 (9-10) ◽  
pp. 753-757 ◽  
Author(s):  
Bożenna Różycka-Roszak ◽  
Hanna Pruchnik
Keyword(s):  
Phase 1 ◽  
Phase Behaviour ◽  
Water Phase ◽  
Lipid Phase ◽  
Dodecyltrimethylammonium Bromide ◽  
Phase 2 ◽  
H Nmr ◽  
Dodecyltrimethylammonium Chloride ◽  
Series Of Experiments ◽  
Mixed Film

Abstract Effects of dodecyltrimethylammonium chloride (DTAC), dodecyltrimethylammonium bromide (DTAB) and dodecyltrimethylammonium iodide (DTAI) on thermotropic phase behaviour of phosphatidylcholine bilayers containing cholesterol as well as on 1H NMR spectra were studied. Two series of experiments were performed. In the first one the surfactants were added to the water phase while in the other directly to the lipid phase (a mixed film from cholesterol, surfactant and phosphatidylcholine was formed). The effects of particular surfactants on the main phase transition temperature, Tm, were more pronounced when added to the lipid phase (2nd method) than to the water phase ( 1st method); the opposite happened when cholesterol was absent (Różycka-Roszak and Pruchnik 2000, Z. Naturforsch. 55c, 240-244). Furthermore, in the case of the first method the transitions were asymmetrical while in the second method nearly symmetrical. It is suggested that surfactant poor and surfactant rich domains are formed when surfactants are added to the water phase.

Sign in / Sign up

Export Citation Format

Share Document