Maximal force characteristics of the Ca2+-powered actuator of vorticella convallaria

Sangjin Ryu, Matthew J. Lang, Paul Matsudaira

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


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 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.

Original languageEnglish (US)
Pages (from-to)860-867
Number of pages8
JournalBiophysical journal
Issue number5
StatePublished - Sep 5 2012

ASJC Scopus subject areas

  • Biophysics


Dive into the research topics of 'Maximal force characteristics of the Ca<sup>2+</sup>-powered actuator of vorticella convallaria'. Together they form a unique fingerprint.

Cite this