Title
Novel touch-induced, Ca(2+)-dependent phobic response in a flagellate green alga
UMMS Affiliation
Department of Cell Biology
Date
1-1-1994
Document Type
Article
Subjects
Algae, Green; Barium; Calcium; Cell Movement; Flagella; Image Processing, Computer-Assisted; Light; Stress, Mechanical; Time Factors; Videotape Recording
Abstract
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 base to tip. Upon contact with surfaces or other cells, S. similis responds with rapid backward swimming, covering distances of up to 50 microns 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 microns.sec-1) or slow deceleration; and (3) a deceleration phase of approximately 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).
Rights and Permissions
Citation: Cell Motil Cytoskeleton. 1994;29(2):97-109. Link to article on publisher's site
Related Resources
PubMed ID
7820869
Journal Title
Cell motility and the cytoskeleton