CHANGES IS PHOSPHOLIPIDS DURING THE CELL-CYCLE OF MYXOMYCETE PHYSARUM-POLYCEPHALUM

The rate of P-32(i) incorporation into the main membrane phospholipid fractions, i.e. phosphatidylcholine (PC), phosphatidylethanolamine (PE ) and phosphatidylinositol (PI), as well as their contents in the cell s during synchronous growth of the myxomycete, Physarum polycephalum, have been studied. It has been found that both the phospholipid levels and the rates of P-32(i) incorporation increase during the S phase ti ll the early G(2) phase, remain nearly constant during the G(2) phase and fall to the initial level at the end of the G(2) phase and in mito sis. It has been revealed that the rate of P-32(i) incorporation into PC is very low compared to PE and PI, in spite of the fact that the PC level is the highest. The possible reasons of this phenomenon are dis cussed.