Brokaw, Charles J. (1991) Microtubule sliding in swimming sperm flagella: direct and indirect measurements on sea urchin and tunicate spermatozoa. Journal of Cell Biology, 114 (6). pp. 1201-1215. ISSN 0021-9525 http://resolver.caltech.edu/CaltechAUTHORS:BROjcb91
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Direct measurements of microtubule sliding in the flagella of actively swimming, demembranated, spermatozoa have been made using submicron diameter gold beads as markers on the exposed outer doublet microtubules. With spermatozoa of the tunicate, Ciona, these measurements confirm values of sliding calculated indirectly by measuring angles relative to the axis of the sperm head. Both methods of measurement show a nonuniform amplitude of oscillatory sliding along the length of the flagellum, providing direct evidence that "oscillatory synchronous sliding" can be occurring in the flagellum, in addition to the metachronous sliding that is necessary to propagate a bending wave. Propagation of constant amplitude bends is not accomplished by propagation of a wave of oscillatory sliding of constant amplitude, and therefore appears to require a mechanism for monitoring and controlling the bend angle as bends propagate. With sea urchin spermatozoa, the direct measurements of sliding do not agree with the values calculated by measuring angles relative to the head axis. The oscillation in angular orientation of the sea urchin sperm head as it swims appears to be accommodated by flexure at the head- flagellum junction and does not correspond to oscillation in orientation of the basal end of the flagellum. Consequently, indirect calculations of sliding based on angles measured relative to the longitudinal axis of the sperm head can be seriously inaccurate in this species.
|Additional Information:||Copyright © 1991 by The Rockefeller University Press. Received for publication 11 March 1991 and in revised form 7 June 1991. I am happy to acknowledge the assistance provided by Sandra Nagayama, Holly Dodson, and Jim Pacheco. Financial support was provided by National Institutes of Health grants GM-18711, RR-07003 (Biomedical Research Support Grant), AG 08787 (Small Instrumentation Grant [SIG]), and HL 41728 (SIG).|
|Subject Keywords:||WAVEFORMS; ASYMMETRY; FILAMENT; MOTILITY; MODEL; BENDS|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Lindsay Cleary|
|Deposited On:||08 Nov 2006|
|Last Modified:||26 Dec 2012 09:16|
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