Figure 2.

Microtubule structures as formed during space flight. Microtubules were assembled once microgravity conditions were obtained. (Left and Center) Shown are the self-organized morphologies that arise for samples placed on the on-board 1 × g centrifuge, with the centrifugal field along and perpendicular to the long axis of the sample cuvette. The centrifuge was stopped after 13 min, immediately before re-entry, and the samples were left under 1 × g conditions for a further 5 h while the structures developed. (Right) Almost no self-organization occurs for samples subject to weightlessness during the first 13 min.