Abstract
1. In biotin deficient yeast, thickening of cell wall was conspicuous at the middle log phase in the Am medium, whereas it was not in the aged cells. The cells cultivated in the Cas medium do not have thickened cell wall even in biotin deficiency. The ratio of mannan to glucan also decreased in the Cas medium, as well as in the Am medium, but, in pantothenic acid deficiency, the ratio did not decrease. In general, total amounts of glucan and mannan showed good parallelism with the thickness of cell wall observed in electron microscopy.
2. Investigations were made on the change of mannan and glucan of yeast at the process of the dead cell formation which appeared in the biotin- free aspartic acid medium and the results showed that mannan tended to increase.
