Fig. 7. Precursor requirements for T. gondii synthesis of phosphatidylcholine. Either CHO cells alone (CHO panel, H lanes), 89.1 cells alone (89.1 panel, H lanes), or hosts harboring T. gondii (CHO and 89.1 panels, T lanes) were pulse-labeled with [¹⁴C]choline. Following the removal of the label, the cultures were chased for the indicated time periods with label-free media. The cells were then harvested and the parasites in the T samples were isolated. Samples were normalized for protein concentration, resolved by thin layer chromatography using the solvent system chloroform/methanol/acetic acid/water (25:15:4:2), and lipids detected by autoradiography after visualizing standards.