Effect of soluble and membrane proteins upon diethyl ether extraction of aqueous phospholipid dispersions

Abstract

The effect of proteins upon diethyl ether extraction of phospholipids from aqueous dispersions has been investigated as a model for elucidating lipid‐protein interactions in the more complex membrane systems. Mixed phospholipids having a net anionic charge or purified lecithin (a zwitterion) are extracted from water dispersions into ether only after addition of salts. Basic proteins (lysozyme and cytochromec), by ionically binding phospholipids, allow extraction. Phospholipids are extracted together with the proteins in the form of neutralized lipid‐protein complexes. On the other hand, lipid depleted mitochondria (a hydrophobic protein residue after acetone extraction of mitochondria), after reconstitution with phospholipids, do not allow phospholipid extraction unless salts or basic proteins also are added to the system. This observation indicates that, in reconstituted membranes, the phospholipids are largely in the bilayer form with the polar heads still charged and susceptible to ether extraction only after neutralization with salts or basic proteins.

Heat Shock Improves Random Spore Analysis in Diverse Strains of Saccharomyces cerevisiae

“…Procedures for enriching yeast cultures for sporulated cells typically exploit the differential sensitivity of spores and vegetative cells to stressful conditions. There are numerous techniques for accomplishing this, which tend to involve caustic reagents such as diethyl ether that kill vegetative cells (Dawes and Hardie, 1974;Parenti-Castelli et al, 1974), and expensive lytic enzymes that weaken ascus walls and physically break up spores of a tetrad (Sherman, 2002). Due to the general effectiveness and robustness of these techniques, laboratories tend to develop specific in-house protocols for RSA based on their specific needs and resources, though some studies have examined ways to optimize efficiency and throughput (e.g., Bahalul et al, 2010).…”

Fluidizing effect of endogenous ubiquinone in bovine heart mitochondrial membranes

“…This result is unexpected, since it was originally assumed that the solvent extracts only neutral lipids from lyophilized mitochondria [14]. It has been reported, however [24,25], that several conditions may i?duce extraction of phospholipids by nonpolar solvents. The results with the deep spin label 16-NS are rather different ( fig.3,4); pentane extraction induces a significant increase of rc, and significant restoration is achieved by addition of either the pentane extract or Q~o (p < 0.01).…”

Determination of the efficient enzyme concentration for lytic digestion of vegetative cells but not spores in Schizosaccharomyces pombe

“…For the complete elimination of vegetative cells another lytic enzymes, such as zymolyase, might be used. Alternatively, it was reported that use of ether preferentially destrois cell walls of vegetative cells rather than spores (Parenti-Castelli et al, 1974;Dawes and Hardy, 1974). Combination of both ether and zymolyase is another possible way of vegeative cell destruction (Bahalul et al, 2010), however this treatment leads to reduction of spore recovery.…”