FIG. 1.

HU Synchronization of procyclic T. brucei. (A) Cells were treated with 0.2 mM HU for 12 h (0 h to 12 h), stained with propidium diiodide, and analyzed by flow cytometry. (B) Cells were treated the same as described for panel A, but the results are from the period after HU washout (12 h to 24 h). Panels A and B are from different but identical experiments. (C) Growth of T. brucei in medium supplemented with 0.2 mM HU (•), 1 mM HU (▴), or no HU (⧫). Extrapolation of the growth curve, after washout of 0.2 mM HU, indicated a lag of ∼6 h before the resumption of normal growth. Values on the y axis were calculated from measured values of cells/ml multiplied by the dilution factor.