The in vivo incorporation of [32P]-labeled orthophosphate into pyrophosphatidic acid and other phospholipids of Cryptococcus neoformans through cell growth.

Cryptococcus neoformans was cultured in a liquid medium containing [32P]-orthophosphate and harvested at various stages of cell growth. An aliquot of the [32P]-labeled cells was transferred to a nonradioactive medium, and the culture was continued again for some hours. The [32P]-radioactivity composition and the phosphorus composition of individual phospholipids relative to the total phospholipid through the incubation periods were estimated. Although levels of major phospholipids remained constant throughout the cell growth, the distribution pattern of the [32P]-radioactivity of individual phospholipids changed remarkably along with the progress of cell growth. The changing patterns of the specific radioactivities of individual phospholipids through the growth phase demonstrated that phosphatidic acid was one of the most active metabolites in phospholipids and that pyrophosphatidic acid was also metabolically active.