Metabolic turnover of the lipids of Rhodopseudomonas spheroides

Abstract

Experiments with L-[Me- 14 C]methionine and inorganic 32 P indicate that the lipids of this micro-organism are metabolically stable. Lipids of unpigmented cells were incorporated into chromatophores when these cells were allowed to adapt to semi-anaerobic conditions in the light. The specific radioactivity of the phospholipid of the chromatophores was the same as that of the adapted cells; thus it appears that no distinction can be made between different parts of the cytoplasmic membrane system with respect to the labelling of the lipids. It is concluded that chromatophores originate from the cytoplasmic membrane and remain structurally a part of it.