Phospholipids in Trypanosoma cruzi : Phosphoinositide composition and turnover

The polyphosphoinositides from Trypanosoma cruzi were isolated by preparative thin‐layer chromatography (TLC) and identified. When myo‐[ 3 H]inositol was present in the culture medium for five days, analyses showed the presence of phosphatidylinositol (PI), lysophosphatidylinositol (lysoPI), phosphatidylinositol 4‐phosphate (PIP) and phosphatidylinositol 4,5‐bisphosphate (PIP 2 ). Short‐term incubation with 32 P i led to higher percentages of incorporation into phosphatidylethanolamine (PE), lysophosphatidylethanolamine (lysoPE) and PI compared to the other glycerophospholipids. The phosphoinositides (PI, PIP and PIP 2 ) contained a larger proportion of unsaturated than saturated fatty acids. High proportions of 18∶2 were found in the three phosphoinositides analyzed, whereas the major saturated fatty acid was 18∶0. Watersoluble inositol phosphates (IP, IP 2 and IP 3 ) were also identified.