Figure 4.

Time course showing a reversible change in the sliding movement of an actin filament with a single temperature pulse. (A) Snapshots of a sliding actin filament (1.1 μm long) at 1/30-s intervals. A laser pulse of 1/16-s duration was given halfway at 0.19 s. (Scale bar, 5 μm.) (B) Time course of sliding movement of the actin filament; displacement of the centroid of the fluorescence image of the actin filament is shown by ○. (C) The temperature estimated from the average intensity of the filament at 1/60-s intervals. In this particular case, odd and even fields of interlaced images were analyzed separately. The coverslip temperature was kept at 18°C ± 1°C.