Metabolism of alpha-glyceryl ethers by Crithidia fasciculata. I. Study of the in vivo degradation of exogenous chimyl and batyl alcohols.

Abstract

[14C] chimyl and [3H] batyl alcohols were added to Crithidia fasciculata cultures during the mid-log phase of cell growth, and the lipid extracts of the cells were analyzed for degradation products. C. fasciculata cells were able to take up exogenous glyceryl ethers, and in amounts as high as the endogenous lipid content. The glyceryl ether taken up by the cells was incorporated into lipids either prior to the ether bond cleavage or after degradation to fatty acid. The extent of degradation and the degree of incorporation of degradation products into cellular lipid were higher for chimyl than for batyl alcohol. Batyl alcohol was not metabolized efficiently, leading to the formation of large intracellular pools of free substrate. One product of glyceryl ether degradation was identified as alkyl-dihydroxy acetone, and was detected inside and outside of the cells. The data strongly suggest that this product is the first stable intermediate in the degradation process and indicate that the extracellular formation of alkyl-dihydroxy acetone is due to the action of exoenzymes secreted by the cells. The constant detection of alk-l-enyl glycerol among the degradation products indicates the existence of a second mechanism in C. fasciculata for converting the alkyl-to alkenyl-glycerol.