Kinetics of XXXX -induced fusion of cell-size liposomes with monolayers in solutions of different osmolarity.

@entity3636 @entity8558 @entity969 @entity460 @entity3282
The effects of osmolarity, @entity460 concentration and cell-size liposomes in the subphase on the surface tension of phospholipid monolayers were investigated. The monolayers were spread from @entity3636 solutions of @entity8558 at air/water solution interface. The liposomes (of average diameter 3 micron) were formed from @entity8558 /egg lecithin (1:2) mixtures in water or 0.1 M water solutions of @entity969 . For this system there were critical concentrations of @entity460 ions to produce a large reduction of the monolayer surface tension. The threshold @entity460 concentrations depended upon the @entity969 concentration in the subphase. Without @entity969 the threshold @entity460 concentration was 8 mM, while for isoosmotic @entity969 solutions (0.1/0.1 M in/out of liposome) it was 14 mM. It sharply increased to 28 mM @entity3282 at @entity969 concentration difference across the liposome membrane 0.02 M and decreased to 26 mM, 19 mM, and 18 mM with further increase of that difference to 0.04 M, 0.06 M, and 0.08 M, respectively. The rate of monolayer surface tension decrease was measured as a function of time at 30 mM @entity3282 and different @entity969 concentrations in the subphase solution. The initial rates at first decreased with increasing the osmotic pressure and after that they increased. The minimum occurred at @entity969 concentration gradient across the liposome membrane 0.02 M, i.e., at the point of maximum threshold @entity460 concentration required for large decrease of the monolayer surface tension. These facts may be explained by recent theories of dynamics of adhesion, instability and fusion of membranes modeled as thin films.
