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G Dresdner

Publications and source records attributed to G Dresdner.

9 recordsLinked to original sources
PubMed1982

Preparation and properties of spin-labeled lecithin-cholesterol liposomes.

Lecithin-cholesterol vesicles of various compositions containing membrane-bound spin-labeled cholestane can be prepared by appropriate choice of initial concentrations of components during sonication. Increasing incorporation of spin label increases incorporation of cholesterol and decreases incorporation of lecithin, with the result that liposomes with cholesterol-lecithin molar ratios larger than 2 can be obtained. Besides associating with cholesterol-lecithin complexes in the liposome, the spin label seems to associate with cholesterol. Changes of the paramagnetic resonance spectrum of the liposome-bound spin label due to changes in liposomal cholesterol and spin label mole fractions - assessed by three parameters - can be used in cell-liposome interaction studies.

Cholesterol↗
PubMed1982

Binding and incorporation of lecithin-cholesterol vesicles to lymphocytes: a spin-label study.

When lecithin-cholesterol vesicles, containing the membrane-bound spin probe 3-doxyl-cholestane, were set in contact with mouse lymphocytes, the vesicles adsorbed to the cell and vesicle-membrane components were transferred to it. The spin probe was enzymatically reduced at the inside of the cell membrane. The spin-label method provided a means to determine quantitatively the extent of vesicles adsorption and vesicle-cell fusion by measuring the transfer of vesicles membrane material to the cell. This method, together with the reduction of spin label by the cell, allowed also a quantitative estimate to the extent of endocytosis during cell-liposome interaction.

Animals↗
PubMed1978

Rapid spectrophotometric determination of Acholeplasma laidlawii membranes.

The amount of Acholeplasma laidlawii membranes can be accurately, rapidly, and simply determined by spectrophotometric measurements after solubilization in 0.02 M SDS, 0.02 M Tris-HCl (pH 8.0). Extinction coefficients from the 260- to 300-nm-absorption region are adequate for quantitative membrane determination. The following values were found: E1%1cm,280 = 9.11 +/- 0.63, E1%,S1cm,280 = 8.52 +/- 0.40 (corrected for light scattering), E1%1cm,280--310 = 8.15 +/- 0.35. The last value is the most satisfactory for routine analysis. These coefficients are not affected by large differences in the carotene and flavin contents of the membranes or by spectral changes that occur when the membranes are exposed to light. The precision obtained with this method is comparable with that achieved in spectrophotometric determinations of proteins. As little as 6 microgram of membrane can be measured in 50-microliter samples.

Acholeplasma laidlawii↗
PubMed1977

Effect of various culturing conditions of Acholeplasma laidlawii on the yield and properties of the cells and cell membrane.

Acholeplasma laidlawii strain B cell cultured in complex medium have an optimal temperature of growth at 31 degrees. Maximal growth at this temperature is 80% higher than at 37 degrees. By stirring of the culture, the yield of the cell mass of 4 liter-cultures increases by 200%. With these modifications the yield of cell membranes increases 3--4 times with respect to that of static culturing at 37 degrees. Membranes obtained from better aerated cultures have a lower flavin and carotenoid content. Membranes obtained from agitated cultures show a higher content of the more insoluble membrane-core proteins. It is suggested that these proteins play a role in membrane and cell adhesiveness.

Acholeplasma laidlawii↗