METABOLISM OF ALPHA-GLYCERYL ETHERS BY TETRAHYMENA PYRIFORMIS .I. CHARACTERISTICS OF IN VIVO DEGRADATION SYSTEM

1. 1. Tetrahymena pyriformis W absorbs, within 30 min, over 90% of the [3H]-chimyl alcohol added to the growth medium as an aqueous dispersion in concentrations up to 1.5-2.0 μmoles per 107 cells. After the initial period, a small proportion of the absorbed glyceryl ether remains in the free form and continues to be incorporated slowly into the lipids. The major part of absorbed chimyl alcohol is rapidly incorporated (either intact, or after production of fatty acids through cleavage of the ether bond) into the cellular lipids, whose composition is thereby significantly altered. As ths amount of administered chimyl alcohol increases, the content of glyceryl-ether containing phospholipid reaches maximal levels and abnormally high amounts of triglyceride accumulate. 2. 2. The rate of glyceryl-ether cleavage is largely proportional to the amount of chimyl alcohol added, being very pronounced at high concentrations of added substrate. However, it has been shown that this ability of Tetrahymena to degrade glyceryl ethers is not due to the action of induced enzymes. 3. 3. The possibility of the formation of two substrate pools upon glyceryl-ether absorption by the cells, as suggested by the radioactivity patterns and the time-course study of chimyl-alcohol incorporation into the lipids, was further investigated by blocking vacuole formation with dinitrophenol. This mechanism of glyceryl-ether utilization by Tetrahymena cells is discussed in detail. © 1969.