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Using a Microfluidics Device for Mechanical Stimulation and High Resolution Imaging of C. elegans
Published on: February 19, 2018
Maximal force characteristics of the Ca(2+)-powered actuator of Vorticella convallaria
Sangjin Ryu1, Matthew J Lang, Paul Matsudaira
1Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.
Abstract:
The millisecond stalk contraction of the sessile ciliate Vorticella convallaria is powered by energy from Ca(2+) 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 μm 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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