Fig. 5

Abnormal centrosome numbers in H₂O₂ hES cells. HUES3 and HUES7 cells were treated by increasing H₂O₂ concentrations during 2 and 24 h. Between 250 and 270 cells were counted for each control and treatment condition. Both cell types were stained for γ-tubulin (red) and Hoechst 33342 (blue), at control and at each H₂O₂ treatment. Where the centrosomes are not visible enough, the area enlarged is shown by a smaller box. In control most cells display normal number of centrosomes with either one or two centrosomes (c1, c2, f1 and f2). By the increase of H₂O₂ treatment many cells display more than two centrosomal structures: c3 and f3, 16 μM; c4 and f4, 32 μM. These multiple centrosomal structures are either distributed in close proximity to each other (f3 and c3) or throughout the cell (indicated by arrows picture f4). The percentage of HUES3 with more than two centrosomes increases sharply between 32 and 64 μM only for 24 h treatment (a). The percentage of HUES7 with more than two centrosomes increases significantly at 32 μM condition only for 24 h treatment (d). Of the cells displaying more than two centrosomes at 24 h H₂O₂ treatment, the majority has three centrosomes, and some have four or more (b and e). Two groups χ² square test, p ≤0.05