Reports

Direct measurements of sliding between outer doublet microtubules in swimming sperm flagella

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Science  24 Mar 1989:
Vol. 243, Issue 4898, pp. 1593-1596
DOI: 10.1126/science.2928796

Abstract

The relative motion of 40-nanometer gold beads bound to the exposed outer doublet microtubules of demembranated sea urchin sperm flagella has been observed and photographed during adenosine triphosphate (ATP)-reactivated swimming. This direct demonstration and measure of sliding displacements between outer doublet microtubules in actively bending flagella verifies the original sliding microtubule model for ciliary bending that was established by electron microscopy of fixed cilia and provides a new, functional measure for the diameter of the flagellar axoneme of 132 +/- 8 nanometers.