Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 14-Day Trial for You or Your Team.

Learn More →

Control of Contractility in Spirostomum by Dissociated Calcium Ions

Control of Contractility in Spirostomum by Dissociated Calcium Ions The freshwater protozoan, Spirostomum ambiguum , exhibits generalized contraction when electrically stimulated with a DC pulse. Light and electron microscopic studies show a subcortical filamentous network, believed responsible for generating contractile tension, in association with vesicles which were shown to accumulate calcium oxalate precipitates. Organisms microinjected with the calcium-sensitive, bioluminescent protein, aequorin, emit light when stimulated to contract. Analyses of cinefilm records of electrically induced contraction indicate that contraction may occur up to 25 msec after the onset of stimulation at a point when the calcium-aequorin light emission is at a peak. The evidence shows that calcium release from an interval compartment is directly associated with the onset of contraction in Spirostomum , and that the removal of calcium, through some internal sequestering mechanism, signals relaxation. Footnotes Submitted: 19 September 1969 http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png The Journal of General Physiology Rockefeller University Press

Control of Contractility in Spirostomum by Dissociated Calcium Ions

The Journal of General Physiology , Volume 56 (2): 168 – Aug 1, 1970

Loading next page...
 
/lp/rockefeller-university-press/control-of-contractility-in-spirostomum-by-dissociated-calcium-ions-g5QJ9no637

References (19)

Publisher
Rockefeller University Press
Copyright
© 1970 Rockefeller University Press
ISSN
0022-1295
eISSN
1540-7748
DOI
10.1085/jgp.56.2.168
Publisher site
See Article on Publisher Site

Abstract

The freshwater protozoan, Spirostomum ambiguum , exhibits generalized contraction when electrically stimulated with a DC pulse. Light and electron microscopic studies show a subcortical filamentous network, believed responsible for generating contractile tension, in association with vesicles which were shown to accumulate calcium oxalate precipitates. Organisms microinjected with the calcium-sensitive, bioluminescent protein, aequorin, emit light when stimulated to contract. Analyses of cinefilm records of electrically induced contraction indicate that contraction may occur up to 25 msec after the onset of stimulation at a point when the calcium-aequorin light emission is at a peak. The evidence shows that calcium release from an interval compartment is directly associated with the onset of contraction in Spirostomum , and that the removal of calcium, through some internal sequestering mechanism, signals relaxation. Footnotes Submitted: 19 September 1969

Journal

The Journal of General PhysiologyRockefeller University Press

Published: Aug 1, 1970

There are no references for this article.