Maximal Force Characteristics of the Ca[superscript 2+]-Powered Actuator of Vorticella convallaria
Author(s)Ryu, Sangjin; Lang, Matthew J.; Matsudaira, Paul T.
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The millisecond stalk contraction of the sessile ciliate Vorticella convallaria is powered by energy from Ca[superscript 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.
DepartmentMassachusetts Institute of Technology. Department of Biological Engineering; Massachusetts Institute of Technology. Department of Biology; Massachusetts Institute of Technology. Department of Mechanical Engineering; Whitehead Institute for Biomedical Research
Ryu, Sangjin, Matthew J. Lang, and Paul Matsudaira. “Maximal Force Characteristics of the Ca2+-Powered Actuator of Vorticella Convallaria.” Biophysical Journal 103, no. 5 (September 2012): 860–867. © 2012 Biophysical Society
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