Transfer of phospholipids between mesosomes and protoplasts from Bacillus subtilis

1. Phospholipids were more intensively labelled from ammonium [1-14C]glycerophosphate in mesosomes than in protoplasts isolated from Bacillus subtilis. 2. When mesosomes, containing phospholipids labelled from sodium-[32P] phosphate were incubated with non radioactive protoplasts, labelled phospholipids were recovered in protoplasts after incubation. 3. This transfer of phospholipids from mesosomes toward protoplasts is time-dependent. 4. Soluble proteins obtained from Bacillus subtilis after ammonium sulphate precipitation were separated on a Sephadex G-100 column. 5. The two main fractions were able to accelerate the transfer of phospholipids from mesosomes toward protoplasts. 6. The first peak stimulated more actively the transfer of phosphatidylethanolamine whereas the second one preferentially accelerated the transfer of phosphatidylglycerol and diphosphatidylglycerol.