Studies on the Cell Wall of Chlorella III. Incorporation of Photosynthetically Fixed Carbon into Cell Walls of Synchronously Growing Cells of Chlorella ellipsoidea

The carbon metabolism in cell walls of Chlorella ellipsoideawas studied by following ¹⁴C incorporation into cell wall constituentsin photosynthesizing, synchronously growing cells. The rateof incorporation was higher at an early growth phase of thecell cycle. The ¹⁴C was incorporated into both the major cellwall constituents, hemicellulose and ‘rigid wall’,and the radioactivity in the latter was distributed into itstwo components, glucosamine and amino acids. In pulse-chaseexperiments, the ¹⁴C fixed photosynthetically in the precedingcell cycle was rapidly transferred into the cell wall constituentsat the early growth phase of the ongoing cell cycle, and thereafterwas gradually released from the cell walls, although the totalamount of ¹⁴C in the cells remained constant. It was concludedthat the cell wall constituents are turned over during the growthphase of the algal cell cycle, and that the cell wall metabolismin the ongoing cell cycle is closely connected with the carbonmetabolism in the preceding cell cycle. (Received February 3, 1982; Accepted June 21, 1982)