Fig. 2. Neutral lipid handling by intracellular parasites. The indicated fluorophore-conjugated probes were introduced to hosts alone (host and -ctl) or hosts infected with T. gondii before (TL) or after (LT) labeling. Lipids of hosts (host), isolated parasites (TL, LT), or contaminating membranes (-ctl) were resolved by thin layer chromatography. BODIPY-fatty-acid-labeled samples were resolved by developing TLC plates in hexane/ether/acetic acid (70:30:1), whereas NBD-cholesterol-labeled samples were resolved by developing first with hexane/ether/acetic acid (70:30:1), then with toluene/acetone (70:10), and finally with chloroform/acetic acid (96:4), allowing the plates to dry between each development. Lipids were detected by illumination of the plates with UV light. O, origin. The migration of the fluorescent probes NBD-cholesterol (chol.), BODIPY-C12 (C12), and C4-BODIPY-C9 (C4C9), as well as the cholesteryl ester standard cholesteryl BODIPY-C12 (chol. C12) are noted. Presumed cholesteryl esters are indicated with asterisks and metabolites of the BODIPY-fatty acids are indicated with arrowheads. The prominent species at the origin of the C12 and C4C9 panels is suspected to be a BODIPY-phospholipid on the basis of its migratory behavior in very polar solvents.