Novel touch-induced, Ca2+-dependent phobic response in a flagellate green alga

Journal article

Publication Details

Author(s): Kreimer G, Witman GB
Journal: Cell Motility and the Cytoskeleton
Publisher: John Wiley & Sons, Ltd
Publication year: 1994
Volume: 29
Journal issue: 2
Pages range: 97-109
ISSN: 0886-1544


The biflagellate green alga Spermatozopsis similis exhibits a remarkable avoidance reaction in addition to the photophobic or stop response characteristic of such algae. S. similis normally swims forward with its anteriorly attached flagella directed posteriorly and propagating sine-like waves from base to tip. Upon contact with surfaces or other cells, S. similis responds with rapid backward swimming, covering distances of up to 50 mu m in 140 to 220 msec. This reaction, which we term the mechanoshock response, also can be triggered by vigorous mechanical stimulation, but not by physiological light intensities. It consists of 3 phases: (1) a rapid acceleration phase with average duration of 31 msec; (2) a phase of about 66 msec with constant high speed (maximal velocities of > 600 mu m.sec(-1)) or slow deceleration; and (3) a deceleration phase of similar to 83 msec, followed by a stop or short period of circling. The cells then resume forward swimming in a random direction. Prior to the mechanoshock response the flagella rapidly are brought together into a close parallel configuration extending anteriorly of the cell body. They then appear to propel the cell by undulatory beating, while the cell describes a pronounced helical path. Small decreases in the extracellular Ca2+ concentration, as well as low concentrations of Ba2+, strongly suppress the probability of this phobic reaction. We conclude that this mechanoshock response involves large Ca2+ influxes, probably mediated by mechanosensitive and/or stretch-activated ion-channel(s). (C) 1994 Wiley-Liss, Inc.

External institutions
Clark University
Universität zu Köln

How to cite

Kreimer, G., & Witman, G.B. (1994). Novel touch-induced, Ca2+-dependent phobic response in a flagellate green alga. Cell Motility and the Cytoskeleton, 29(2), 97-109.

Kreimer, Georg, and George B. Witman. "Novel touch-induced, Ca2+-dependent phobic response in a flagellate green alga." Cell Motility and the Cytoskeleton 29.2 (1994): 97-109.


Last updated on 2018-20-07 at 21:10