FIG. 8.

(A) Incorporation of [³H]choline into SM of mock-infected mouse L cells (MI) and C. trachomatis L2-infected mouse L cells (L2) grown in the absence (open bars) and presence (hatched bars) of 5 μg of brefeldin A ml⁻¹. [³H]SM synthesis was 18,347 dpm mg⁻¹ in mock-infected control cells and 16,926 dpm mg⁻¹ in L2-infected cells. (B) Transport of natural [³H]choline-labeled SM to the surfaces of mock-infected mouse L cells and C. trachomatis L2-infected mouse L cells grown in the absence (open bars) and presence (hatched bars) of 5 μg of brefeldin A ml⁻¹. Hydrolyzable cell surface SM was quantitated with an exogenous sphingomyelinase treatment as described in Materials and Methods. Results are averages of results from two separate experiments; duplicate results varied by less than 10%.