Energy dependence of human embryonic stem cell (hESC) chromatin movement. (A)-(D) A hESC nucleus expressing H2B-GFP before ATP depletion, one hour after ATP depletion, two hours after and four hours after ATP depletion, with the chromatin density region tested from each stage of depletion highlighted by a red box. (E)-(H) Tau phase map of the free NADH content (scale from 2 ns = high free NADH to 5 ns = low free NADH) that surrounds the selected chromatin density region from different stages of ATP depletion (red box, selected from nuclei (A)-(D)), with the tau phase profile recorded along the actual line scan (black arrow) superimposed. (I)-(L) Intensity carpet of H2B-EGFP fluorescence along the line scan performed across the chromatin density region from different stages of ATP depletion. (M)-(P) Auto- and cross correlation analysis of the Gaussian track derived for chromatin movement of the density region centered at two adjacent middle columns, before, one hour, two hours and four hours after ATP depletion. (Q) Change in amplitude of chromatin vibration in the X-Y plane upon ATP depletion (N = 5 tracking experiments).