Vesicles preparation

Reverse Phase Evaporation Szoka and Papahadjopoulos (1978) developed the so-called reverse phase evaporation method. Vesicles prepared with this technique (REV) show higher encapsulation efficiencies of hydrophilic compounds than unextruded MLV. 

Brunner, J., Skrabal, P., and Hauser, H. (1976). Single bilayer vesicles prepared without sonication. Physico-chemical piwperlies, Biochim. Biophys. Acta. 455, 322-331. 

Wessmann, G. (1978). Comparison of large unilamellar vesicles prepared by a petroleum ether vaporization method with multila-mellar vesicles ESR, diffusion and entrapment analyses, Bio-chim. Biophys. Acta. 542, 137-153. 

Sarcoplasmic reticulum vesicles prepared from rabbit skeletal muscle were crystallized in a medium of 0.1 M KCl, lOmM imidazole (pH 8), and 5mM MgCl2 by the addition of either CaCl2 (100/rM) or lanthanide ions (1-8 M) that stabilize the E conformation of the Ca -ATPase [119]. After incubation at 2°C for 5-48 hours, crystalline arrays were observed on the surface of about 10 20% of the vesicles in sarcoplasmic reticulum preparations obtained from fast-twitch rabbit skeletal muscles. 

Liposomes, which are lipid bilayer vesicles prepared from mixtures of lipids, also provide a useful tool for studying passive permeability of molecules through lipid. This system has, for example, been used to demonstrate the passive nature of the absorption mechanism of monocarboxylic acids [131]. Liposome partitioning of... 

The opening of masses of ion channels in nematode muscle membranes may be detected using the two-microelectrode voltage-clamp technique. In contrast, the opening of single ion channels may be recorded using the vesicle preparation and patch-clamp technique. These techniques are both described below. 

Martin, R.J., Kusel, J.R. and Pennington, A.J. (1990) Surface-properties of membrane-vesicles prepared from muscle-cells of Ascaris suum. Journal of Parasitology 76, 340-348. 

Mizutani and Whitten, 1985). Vesicles prepared by sonication or vaporization are metastable, and it is necessary to use standard conditions to obtain reproducible kinetic data. 

Thiolysis of p-nitrophenyl acetate Synthetic vesicles prepared by injection. Rates compared with those in aq.CTABr Cuccovia et al., 1979... 

The monomeric PLB mutant was as potent (actually even more so) than the native PLB, which indicated that a PLB pentamer forming a leak channel was unlikely. There is a reported backflux through the Ca-ATPase which is lower in the PLB knockout. In the heart you can make a really good SR vesicle preparation for direct evaluation of SR Ca2+ uptake, but one of the limitations here is that this is difficult for smooth muscle tissues, though the bladder is useful for some quantitative biochemistry. So the question of a PLB leak is still open for smooth muscle but, on the basis of cardiac data, it is unlikely. 

Accumulation/efflux studies can be performed on different cell systems or membrane vesicle preparations. In the accumulation assays, uptake of a probe over time, typically either fluorescent (e.g. calcein-AM (CAM) [25-27]) or radiolabeled, into the cell or membrane vesicles is measured in the presence or absence of a known P-gp inhibitor. As P-gp transports substrates out of the cells, the inhibition of the protein would result in an increase in the amount of the probe in the cell. Accumulation studies in cells that overexpress P-gp can be compared to those obtained in the parental cell line that does not have as high a level of P-gp expression. The probe in the absence of inhibitors shows lower accumulation in P-gp expressing cells than in P-gp deficient cells. Similarly, probe accumulation is increased under conditions where P-gp is inhibited such that the difference in accumulation in P-gp deficient and overexpressing cells, respectively, becomes smaller. Accumulation assays poorly distinguish substrates and inhibitors of P-gp and, as far as transport assays are concerned, are also influenced by a passive diffusion property of molecules [20]. In contrast to transport assays, both accumulation (i.e. calcein-AM assay) and ATPase assays tend to fail in the identification ofrelatively low permeable compounds as P-gp active compounds [20]. 

Figure 1 Freeze-fracture electron micrographs of egg phosphatidylcholine large unilamellar vesicles prepared by extrusion through polycarbonate filters with pore sizes of (A) 400 nm, (B) 200 run, (Q 100 nm, (D) 50 nm, and (E) 30 nm. The bar in panel (A) represents 150nm. Source From Ref. 7.

Walde P, Ichikawa S. Enzymes inside lipid vesicles preparation, reactivity and applications. Biomol Eng 2001 18 143. 

Mui BLS, Cullis PR, Evans EA, et al. Osmotic properties of large unilamellar vesicles prepared by extrusion. Biophys J 1993 64 443. 

Graph 8.3 Group data for the cholesterokphospholipid (CH/PL) molar ratio in the vesicles prepared from gallbladder bile. Data taken from reference 18. 

Fujii R, Mutoh M, Sumizawa T, Chen Z, Yoshimura A, Akiyama S. Adenosine triphosphate-depen-dent transport of leukotriene C4 by membrane vesicles prepared from cisplatin-resistant human epidermoid carcinoma tumor cells. J Natl Cancer Inst 1994 86 1781-1784. 

Yomo, Urabe and coworkers (Yu et al, 2001), for example, reported the expression of a mutant GFP (actually the pET-21-GFPmutl-His6 mutant) in lecithin liposomes. Large GFP-expressing vesicles, prepared by the film hydration method, were analyzed using flow cytometry as well as confocal laser microscopy. 

Fig. 4. Scanning electron micrograph of a crosslinked lipid vesicle prepared by photopolymerization of bis-DenPC. The vesicle is ca. 250 nm in diameter.

Fig. 37a, b. Model proposed according to 31P-NMR signal shape of phase transition range. Membrane structure of mixed vesicles prepared from oppositely charged vesicles a inverse micelle model b bulge model of clusters with different spontaneous membrane bending [310]... 

Dissymmetrical SUVs can be formed by limiting reactions to the outer surfaces of polymerized surfactant vesicles (Fig. 39). Chemical dissymmetry has been created, for example, in polymerized vesicles prepared from surfactants containing ester-linked viologen moieties in their headgroups. Cleavage of the... 

Single-compartment DHP vesicles Single-compartment vesicles prepared from DHP, DODAC (6), and 2 CdS particles prepared in situ in vesicles from Cd2+ and H2S at inner, at outer, and at both of these surfaces CdS particles prepared in situ in vesicles from Cd2+ and H2S at inner, at outer, and at both of these surfaces... 

Single-compartment vesicles prepared from mixtures of DODAC (6) and (n-CigH37)2N+(CH3)CHj-CH2SH, Br CdS particles prepared in situ at both the outer and inner surfaces of vesicles from Cd2+ and H2S... 

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