CHANGE OF PANTOTHENIC ACID CONTENT IN CHLORELLA CELLS DURING THE SULFUR STARVATION AND SUBSEQUENT RESTORATION, AS STUDIED BY THE TECHNIQUE OF SYNCHRONOUS CULTURE

Abstract

1. During the processes of cell division of Chlorella as controlled by the limited supply of sulfur and nitrogen sources, the fate of free and combined pantothenic acid was investigated in connection with the accumulation and disappearance of surplus lipid investigated in the preceding work.
2. When the young and small algal cells (D-cells) were grown synchronously in an S-free medium, the cells grew to some extent, without, however, being able to perform cell division. In the cells thus rendered S-deficient, the formation of pantothenic acid in both free and combined forms was profoundly suppressed, whereas the lipid content increased to an abnormally high level.
3. When the S-starved cells were provided with sulfate alone under photosynthesizing conditions, the cells still remained unable to divide. During this period no significant increase in the amount of combined pantothenic acid occurred, although its free form increased up to the normal level. In this case, the accumulated lipid did not disappear.
4. When the S-starved cells were made capable of performing cell division on being provided with sulfate under non-photosynthesizing conditions, or with sulfate plus nitrate under photosynthesizing conditions, the combined pantothenic acid increased remarkably and the surplus lipid disappeared.
5. Discussions were made on the possible role of the combined pantothenic acid in the algal cell division and on the competitive relation between the processes of photosynthetic growth and cell division in respect to the formation of the factor (probably CoA) containing pantothenic acid as an essential component.