Dynamic fluorescence measurements on the main phase transition of dipalmytoylphosphatidylcholine vesicles

1986 ◽  
Vol 13 (6) ◽  
Author(s):  
A. Genz ◽  
J.F. Holzwarth
Keyword(s):  
Phase Transition ◽  
Main Phase ◽  
Fluorescence Measurements ◽  
Dynamic Fluorescence

Effect of surface ionization of dimyristolyphosphatidic acid vesicle membranes on the main phase-transition enthalpy and temperature

1988 ◽  
Vol 943 (3) ◽  
pp. 522-530 ◽  
Author(s):  
Yoshiron Kaminoh ◽  
Fumiaki Kanô ◽  
Jang-Shing Chiou ◽  
Hiroshi Kamaya ◽  
Sheng H. Lin ◽  
...  
Keyword(s):  
Phase Transition ◽  
Main Phase ◽  
Surface Ionization ◽  
Vesicle Membranes ◽  
Transition Enthalpy ◽  
Effect Of Surface

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.

Effect of Inhalation Anesthetics on Spin-Labeled Cholesterol Containing DPPC Vesicles

1988 ◽  
Vol 43 (3-4) ◽  
pp. 264-268 ◽  
Author(s):  
N. Gulfo ◽  
R. Bartucci ◽  
L. Sportelli
Keyword(s):  
Phase Transition ◽  
Diethyl Ether ◽  
Liquid Crystalline ◽  
Main Phase ◽  
Molar Ratio ◽  
Lipid Phase ◽  
Interfacial Region ◽  
Hydrophobic Core ◽  
Hydrophobic Region ◽  
Inhalation Anesthetics

We have investigated by means of electron spin resonance (ESR) spectroscopy the influence of three inhalation anesthetics, i.e. halothane, chloroform and diethyl ether, on the interfacial and hydrophobic region as well of 38 mol% cholesterol containing DPPC unilamellar vesicles. The study has been carried out in the temperature range 25-45 °C. The variation of the order parameter, S, vs temperature of the lipid phase indicates that with this content of cholesterol the characteristic gel → liquid crystalline main phase transition of DPPC, normally occurring at Tt ~ 41 °C, disappears. When halothane and chloroform are added to the vesicles suspension up to [DPPC]/[anesthetic] molar ratio of 1:1 the main phase transition, as detected with the stearic acid spin label I(12,3), reappears again and it results down shifted at Tt ~ 35 and 39 °C, respectively. In presence of diethyl ether, instead, the main phase transition is not observable also at the highest concentration of anesthetic used. Moreover, halothane and chloroform affect similarly the hydrophobic core of cholesterol-!- DPPC vesicles which, in turn, results to be different from the action exerted by diethyl ether in the same region. The ESR findings are discussed in terms of competitive effects shown by cholesterol and inhalation anesthetics. Moreover, the interfacial region of CHOL + DPPC vesicles results to be the target of anesthetics.

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