L-cycloserine inhibition of sphingolipid synthesis in the anaerobic bacterium Bacteroides levii.

L-cycloserine was found to significantly inhibit the activity of the first enzyme of the sphingolipid pathway when added to growing cultures of Bacteroides levii. The effect of cycloserine on the synthesis of the sphingolipids showed that ceramidephosphorylethanolamine was inhibited to a greater degree than ceramidephosphorylglycerol, although synthesis of both was significantly inhibited by cycloserine as determined by [32P] incorporation and phosphorus determination. In contrast, synthesis of phosphatidylethanolamine and phosphatidylglycerol was not inhibited by L-cycloserine at 100 micrograms/ml. Peturbation of sphingolipid synthesis by L-cycloserine may therefore provide a useful tool for the study of the function of these membrane lipids.