Correlation of side chain mobility with cholesterol retention by phospholipid vesicles

Jacobsohn, Myra K.; Estahani, Mojtaba; Jacobsohn, Gert M.

doi:10.1007/bf02537242

Cited by 6 publications

(9 citation statements)

References 31 publications

(10 reference statements)

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“…At pH 10.4, 150 ~g or 30% of the cholesterol was extracted, but this was more than the amount extracted from single species vesicles. Data from these experiments and those reported earlier (2) indicate that acyl side chain length and unsaturation are important parameters in determining the stability of lipid bilayers.…”

Section: Betacyanin Leakage From Beet Root Cells Incubation Of Beetsupporting

confidence: 68%

“…Phosphatidylcholine {PC), phosphatidylethanolamine {PE) and SP lipids with equimolar amounts of sterol, to which [4-14C]cholesterol (22,000 cpm) had been added, were incorporated into MLV. The procedure for making and incubating MLV and extracting them with petroleum hydrocarbon has been described previously (2). A slight change in the procedure was made in that lipid films were suspended in 0.4 mL of appropriate buffer solutions for 10 rain prior to vortexing with glass beads, and the samples were left undisturbed for 45 to 60 min prior to extraction with solvent.…”

Section: Methodsmentioning

confidence: 99%

“…phase, cholesterol would become accessible to the nonpolar solvent and the sterol would be extracted. This method was used previously to study the influence of side chain mobility, head group type and pH on the stability of bilayers (1,2). Results showed that at moderately acid to neutral pH, phospholipids with mobile side chains and]or those with ethanolamine-containing head groups form unstable bilayers from which cholesterol and phospholipids are readily removable, which may be a manifestation of reverse hexagonal phase formation (3).…”

Section: Lipids 27 694-700 (1992)mentioning

confidence: 99%

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Cell membranes and multilamellar vesicles: Influence of pH on solvent induced damage

Jacobsohn¹,

Lehman²,

Jacobsohn³

1992

Lipids

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Pigment leakage from sheep and horse erythrocytes and from red beet tissue induced by non-polar solvents was determined as a function of pH. The results were compared to disruption of multilamellar vesicles (MLV) composed of phospholipids with equimolar cholesterol under identical conditions of solvent exposure and pH. Solvent access to cholesterol was used to measure vesicle disruption. MLV were made from 1,2-dioleoyl phosphatidylethanolamine, sphingomyelin (SP) and various phosphatidylcholines to simulate the major lipid components of membranes. Pigment leakage from erythrocytes caused by petroleum hydrocarbon (b.p. 60-80 degrees C) was maximal at pH 2-4 and at pH 10, but minimal at pH 6.8; alcohols caused less pigment leakage than petroleum hydrocarbon. Beta-cyanin leakage from beet tissue induced by petroleum hydrocarbon was maximal at pH 2, with very little leakage at pH 4, 6.6 and pH 10. Alcohols caused minimal damage to beet tissue above pH 2. Cholesterol removal by petroleum hydrocarbon from MLV of mixed lipid composition was maximal at pH 2-4, reduced at pH 6.8 and minimal at pH 10. Lipid mixtures in which fatty acyl side chains of one phospholipid were of a different length than the other lost more sterol than mixtures in which the acyl side chains were of identical chain length. MLV with more than 25% SP lost more sterol than those with less or no SP. Results show that in mixtures of phospholipids, SP exposes the hydrocarbon phase of a bilayer to solvent extraction, a property that was also observed in native membranes.(ABSTRACT TRUNCATED AT 250 WORDS)

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Section: Betacyanin Leakage From Beet Root Cells Incubation Of Beetsupporting

confidence: 68%

Section: Methodsmentioning

confidence: 99%

Section: Lipids 27 694-700 (1992)mentioning

confidence: 99%

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Cell membranes and multilamellar vesicles: Influence of pH on solvent induced damage

Jacobsohn¹,

Lehman²,

Jacobsohn³

1992

Lipids

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“…Percentage entrapment efficiency (% EE) was determined by using the petroleum ether extraction method as described by Jacobsohn et al [29] and Nakamura et al [30] Briefly, the unwashed liposome suspension was extracted three times with 3.0 ml of petroleum ether each time. For each extraction, the organic layers were collected into a volumetric flask.…”

Section: Determination Of Liposome Entrapment Efficiencymentioning

confidence: 99%

Distribution ofMelaleuca alternifoliaessential oil in liposomes with Tween 80 addition and enhancement ofin vitroantimicrobial effect

Yan

2015

Journal of Experimental Nanoscience

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Tea tree oil (TTO) exhibits excellent broad-spectrum antimicrobial activity. In order to preserve it from the degradation in the presence of oxygen, light and temperature, TTO was encapsulated in liposomes (LTTOs) using the thinmembrane hydration and sonication method, and characterised by Zetasizer for size and size distribution, transmission electron microscope for morphology, zetapotential for surface charge, entrapment efficiency and TTO release from the nanoparticles. The antimicrobial activities of phosphate-buffered saline solution containing TTO, unloaded liposomes and LTTOs suspension were determined by twofold serial broth dilution technique. The size of LTTOs was 75 nm and the encapsulation efficiency of 96.08% was obtained. LTTOs exhibited slow release of TTO and superior broad-spectrum antimicrobial effects compared with free TTO. Liposomes not only effectively encapsulated TTO to form a stable liposome suspension, but also enhanced inhibition and bactericidal effect on the TTOtolerant strain. The liposomal systems carrying TTO may be a potential alternative for effective antimicrobial agents.

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“…We have described previously a procedure for quantifying lipid retention by multilamellar vesicles (MLV) of phosphatidylcholine (PC) by extraction with a nonpolar solvent (1). The study showed that MLV of PC without cholesterol retained most of their phospholipid upon extraction with petroleum ether, but if the sterol was present, MLV varied in their retention of sterol or phospholipid.…”

Section: Lipids 24 375-382 (1989)mentioning

confidence: 99%

Effect of pH on the affinity of phospholipids for cholesterol

Jacobsohn¹,

Bazilian²,

Hardiman³

et al. 1989

Lipids

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The ability of multilamellar vesicles of phosphatidylcholine and phosphatidylethanolamine in aqueous phase to prevent access to cholesterol by a nonpolar solvent was examined. Phosphatidylethanolamine vesicles. In mixed vesicles, cholesterol was retained in proportion to the amount of phosphatidylcholine. To alter the charge and hydration of head groups, pH was adjusted from 1.2 to 12.5. Above pH 8, both phosphatidylethanolamine and phosphatidylcholine retained sterol in a 1:1 molar ratio of phospholipid to cholesterol, regardless of acyl side chain composition. Between pH 2.0 and pH 8.0, sterol retention varied with type of head group and side chain. Lipids with 16-carbon saturated side chains retained more sterol than 18-carbon unsaturated or 12-carbon saturated side chains. Between pH 1.1 and 2.0, none of the phosphatidylethanolamines retained sterol, but long chain phosphatidylcholines, saturated or unsaturated, retained sterol in a 1:1 molar ratio of phospholipid to sterol. Short chain phosphatidylethanolamines and phosphatidylcholines retained 0 to 20% at the low- to mid-pH range. Size of multilamellar vesicles, measured by Doppler effect light scattering analysis, had no bearing on sterol retention. Sonication of vesicles, which increases surface curvature, increases the retention of sterol. Fluorescence polarization indicated that cholesterol does not interact with DPPC or DLPC side chains. The observations can be interpreted in terms of space requirements of head groups, including charge repulsion and hydration. Other factors, such as monovalent cation replacement by protons, juxtaposition of charged groups on vesicle surfaces and length and unsaturation of acyl side chains affect the affinity of phospholipids for cholesterol.

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Correlation of side chain mobility with cholesterol retention by phospholipid vesicles

Cited by 6 publications

References 31 publications

Cell membranes and multilamellar vesicles: Influence of pH on solvent induced damage

Cell membranes and multilamellar vesicles: Influence of pH on solvent induced damage

Distribution ofMelaleuca alternifoliaessential oil in liposomes with Tween 80 addition and enhancement ofin vitroantimicrobial effect

Effect of pH on the affinity of phospholipids for cholesterol

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