Swimming behaviour of the unicellular biflagellate Oxyrrhis marina: in vivo and in vitro movement of the two flagella

Abstract

The movement of the 2 flagella of Oxyrrhis marina was examined with respect to their individual waveforms and the swimming behaviour of the organism. The longitudinal flagella propagated helicoidal waves whose amplitude decreased toward the tip of the flagellum. Their beat frequencies were 50-60 Hz. The transverse flagella beat helicoidally within a furrow. Sudden changes in the direction of the cell trajectories were generated by transient arrests of the longitudinal flagellum beat, which were accompanied by a switch from the backward orientation to a forward one. This sweeping motion generated the rotation of the cell body. Ca2+ ions highly stimulated the frequencies of this arrest response, which compared to the "walking-stick" behaviour of sea urchin spermatozoa. Isolated flagella were ATP-reactivated after detergent treatment. They exhibited 2 types of motion within the same experimental conditions. A progressive helicoidal motion was generated upon longitudinal flagellum reactivation, whereas a rolling motion with little progression characterized transverse flagellum reactivation. The differences motile behaviour reflect regulations of flagellar movement which were not destroyed by the isolation procedure and may be indicative of regulation of accessory structures. © 1988.