Dose-dependent nonlinear response of the main phase-transition temperature of phospholipid membranes to alcohols

1986 ◽  
Vol 90 (2) ◽  
pp. 157-161 ◽  
Author(s):  
Hiroshi Kamaya ◽  
Shao-mu Ma ◽  
Sheng H. Lin
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Phase Transition Temperature ◽  
Nonlinear Response ◽  
Main Phase ◽  
Phospholipid Membranes ◽  
Dose Dependent

scholarly journals The Effect of Selected Anions on Dipalmitoylphosphatidylcholine Phase Transitions

2002 ◽  
Vol 57 (7-8) ◽  
pp. 712-716 ◽  
Author(s):  
Adriana Przyczyna ◽  
Bożenna Różycka-Roszk ◽  
Marek Langner
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Transition Temperature ◽  
Phase Transition Temperature ◽  
Salt Concentration ◽  
Half Width ◽  
Main Phase ◽  
Interface Properties ◽  
Transition Enthalpy ◽  
Peak Half Width

The effect of three anions, Cl-, Br- and I-, on the phase transitions of dipalmitoylphosphatidylcholine (DPPC) was measured. Main phase transition was modestly affected by these anions in the salt concentration range 0.2 M. For Cl- and Br- the temperature of main phase transition was lower (by about 0.5 °C), its half-width modestly larger and enthalpy practically unchanged, all three parameters were altered to a much larger degree. Main phase transition temperature was 1.5 °C lower and the peak half-width significantly smaller. These changes were not accompanied by any alteration in main phase transition enthalpy. Iodide shifted the pretransition temperature toward lower values and increased its half-width to such an extent that at concentrations above 100 mm it was practically undetectable. Besides cations, the presence of anions also has a distinct effect on lipid bilayer interface properties.

A Semisynthetic 5-n-Alkylresorcinol Derivative and its Effect upon Biomembrane Properties

2007 ◽  
Vol 62 (11-12) ◽  
pp. 881-888 ◽  
Author(s):  
Maria Stasiuk ◽  
Dominika Bartosiewicz ◽  
Jerzy Gubernator ◽  
Katarzyna Cieslik-Boczula ◽  
Martin Hof ◽  
...  
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Phase Transition Temperature ◽  
Ph Value ◽  
Membrane Surface ◽  
Main Phase ◽  
Phospholipid Bilayer ◽  
Low Concentrations ◽  
Packing Defects ◽  
Semisynthetic Derivative

MSAR (1-sulfate-3-myristoyl-5-pentadecylbenzene) is a semisynthetic derivative of 5-npentadecylresorcinol (C15:0). MSAR exhibits hemolytic activity against sheep erythrocytes with a EH50 value of (35 ± 1.7) μm. At low concentrations MSAR also exhibits the ability to protect cells against their hypoosmotic lysis. This protective effect is significant as, at 0.1 μm of MSAR, the extent of osmotically induced cell lysis is reduced by approx. 20%. It was demonstrated that the 9-anthroyloxystearic acid signal was most intensively quenched by MSAR molecules, suggesting a relatively deep location of these molecules within the lipid bilayer. MSAR causes an increase of the fluorescence of the membrane potential sensitive probe. This indicates an alteration of the surface charge and a decrease of the local pH value at the membrane surface. At low bilayer content (1-4 mol%) this compound causes a significant increase of the phospholipid bilayer fluidity (both under and above the main phase transition temperature) of dipalmitoylphosphatidylcholine (DPPC) liposomes. At this low content MSAR slightly decreases the main phase transition temperature (Tc) value. The effects induced in the phospholipid bilayer by higher contents of MSAR molecules (5-10 mol%) make it impossible to determine the Tc value and to evaluate changes of the membrane fluidity by using pyrene-labeled lipid. MSAR also causes a decrease of the activity of membrane-bound enzymes-red blood cell acetylcholinesterase (AChE) and phospholipase A2 (PLA2). MSAR decreases the AChE activity by 40% at 100 μm. The presence of MSAR in the liposomal membrane induces a complete abolishment of the lag time of the PLA2 activity, indicating that these molecules induce the formation of packing defects in the bilayer which may result from imperfect mixing of phospholipids.

scholarly journals Determination of the Main Phase Transition Temperature of Phospholipids by Nanoplasmonic Sensing

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Wen Chen ◽  
Filip Duša ◽  
Joanna Witos ◽  
Suvi-Katriina Ruokonen ◽  
Susanne K. Wiedmer
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Phase Transition Temperature ◽  
Main Phase

The structure of membranes and membrane proteins embedded in amorphous ice

1992 ◽  
Vol 50 (1) ◽  
pp. 432-433
Author(s):  
Uwe Lücken ◽  
Joachim Jäger
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Membrane Proteins ◽  
Phase Transition Temperature ◽  
Lipid Vesicles ◽  
Freezing Stress ◽  
Amorphous Ice ◽  
Different Temperatures ◽  
Band Pass ◽  
Lipid Polymorphism

TEM imaging of frozen-hydrated lipid vesicles has been done by several groups Thermotrophic and lyotrophic polymorphism has been reported. By using image processing, computer simulation and tilt experiments, we tried to learn about the influence of freezing-stress and defocus artifacts on the lipid polymorphism and fine structure of the bilayer profile. We show integrated membrane proteins do modulate the bilayer structure and the morphology of the vesicles.Phase transitions of DMPC vesicles were visualized after freezing under equilibrium conditions at different temperatures in a controlled-environment vitrification system. Below the main phase transition temperature of 24°C (Fig. 1), vesicles show a facetted appearance due to the quasicrystalline areas. A gradual increase in temperature leads to melting processes with different morphology in the bilayer profile. Far above the phase transition temperature the bilayer profile is still present. In the band-pass-filtered images (Fig. 2) no significant change in the width of the bilayer profile is visible.

Molecular Ordering of a Nematogen at Phase Transition Temperature - A Theoretical Study

2002 ◽  
Vol 75 (4-5) ◽  
pp. 413-421
Author(s):  
Durga Prasad Ojha ◽  
Devesh Kumar ◽  
V.G.K.M. Pisipati
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Phase Transition Temperature ◽  
Theoretical Study ◽  
Molecular Ordering
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