Mechanical & Materials Engineering, Department of

 

Document Type

Article

Date of this Version

9-2012

Citation

Biophysical Journal Volume 103 September 2012, pp. 860–867.

Comments

Copyright 2012 by the Biophysical Society.

Abstract

The millisecond stalk contraction of the sessile ciliate Vorticella convallaria is powered by energy from Ca2+ binding to generate contractile forces of ~10 nN. Its contractile organelle, the spasmoneme, generates higher contractile force under increased stall resistances. By applying viscous drag force to contracting V. convallaria in a microfluidic channel, we observed that the mechanical force and work of the spasmoneme depended on the stalk length, i.e., the maximum tension (150–350 nN) and work linearly depended on the stalk length (~2.5 nN and ~30 fJ per 1 mm of the stalk). This stalk-length dependency suggests that motor units of the spasmoneme may be organized in such a way that the mechanical force and work of each unit cumulate in series along the spasmoneme.

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