FIG. 7.

Analysis of sphingolipid synthesis upon aureobasidin A treatment. (A) Representative thin-layer chromatography (TLC) results for inositol-labeled lipids extracted from T. gondii. HFF monolayers were infected with T. gondii and labeled with myo-[³H]inositol in the presence of vehicle (control) or 10 μg/ml of aureobasidin A (AbA) for 24 h. After washing of the cells, T. gondii tachyzoites were harvested, lipids were extracted from 10⁸ parasites, and aliquots were processed by mild alkaline hydrolysis (NaOH) and resolved by TLC analysis in solvent system A. (B) Representative TLC of palmitate-labeled lipids extracted from T. gondii or host cells. Purified parasites (10⁸) or 10⁷ host cells were labeled with [³H]palmitate in the presence of vehicle (Cntl) or 10 μg/ml of aureobasidin A (AbA) for 7 h. Lipids were extracted and resolved by TLC analysis in solvent system B. Cer, ceramide; SM, sphingomyelin. (C) Densitometric quantification of newly synthesized ceramide versus sphingomyelin ratio after labeling with [³H]palmitate. Data are expressed as percentages of newly synthesized ceramide/sphingomyelin in vehicle (Cntl)-treated parasites or host cells.