Membrane biogenesis in Chlamydomonas reinhardi 137 : Cell-cycle variations in the synthesis of phospholipids of non-photosynthetic membranes

To monitor the biogenesis of non-photosynthetic membranes during Chlamydomonas reinhardi 137⁺ vegetative development, the syntheses of phosphatidylethanolamine (PE) and phosphatidylcholine (PC), the alga's two major extra-thylakoid phospholipids, have been examined through the synchronous cycle. Synthesis of both phospholipids is largely confined to the photoperiod (mid-to-late G1), as is the accretion of cellular polar glycerolipid, with negligible lipogenesis in the dark (S, M, and early-to-mid G1). Coincidence between the cyclic variations of non-thylakoid and of thylakoid polar glycerolipid production during the Chlamydomonas cell cycle indicates that the synthesis of membrane molecules serves to both modulate and coordinate the biogenesis of the various cellular membranes in these actively-cycling cells.