Abstract
Kloeckera apiculata, when incubated with thiamine in 2 % glucose solution for 1 hour, absorbed thiamine to the amount of one-tenth the cell weight but protoplasts prepared from Klosckera cells absorbed thiamine incompletely to the amount far less than that of intact cells. Thiamine diphosphate (TDP) was absorbed by the cells as free thiamine to the same extent as thiamine used but TDP was poorly absorbed by protoplasts. TDP, when incubated with intact cells in glucose and molybdate (M/10), was not converted to free thiamine and no absorption of thiamine by cells was demonstrated. S-Carbethoxythiamine (CET) and thiamine propyl disulfide (TPD) stimulated the growth of the yeast more strongly than thiamine but the both were absorbed on cells to the less extent than thiamine. Kl.apiculata, however, when innoculated in the broth containing 2μg of thiamine, CET or TPD, showed better growth and higher content of TDP in cells after incubation with CET or TPD than incubation with thiamine. CET, when incubated with higher quantity of the yeast cells, penetrated into cells by simple diffusion and was easily washed out by isotonic solution. Thiamine was accumulated on the cells completely and could not be washed out by isotonic solution. Penetration of CET into cytoplasm and conversion to TDP might be correlated with higher content of TDP in cells on growth tests.
