Mycoplasma mobile Cells Elongated by Detergent and Their Pivoting Movements in Gliding

Mycoplasma mobile glides on solid surfaces by the repeated binding of leg structures to sialylated oligosaccharide fixed on a solid surface. To obtain information about the propulsion caused by the leg, we made elongated and stiff cells using a detergent. Within 30 min after the cells were treated with 0.1 % Tween 60, the cells were elongated from 0.8m to 2.2m in length while maintaining their gliding activity. Fluorescence and electronmicroscopy showed that a part of the cytoskeletal structure was elongated, while the localization of proteins involved in the gliding was not modified significantly. The elongated cells glided with repeated pivoting around the cellular position of gliding machinery by 10 degrees of amplitude at a frequency of 2 to 3 times per second, suggesting that the propulsion in a line perpendicular to the cell axis can occur with different timings. The pivoting speed decreased as the cell length increased, probably from the load generated by the friction. The torque required to achieve the actual pivoting increased with the cell length without saturation, reaching 54.7 pN nm at 4.3m in cell length. Mycoplasmas are commensal and occasionally parasitic bac-teria that lack peptidoglycan layers and have small genomes (29).Mycoplasmamobile, a fish pathogen, forms amembrane pro-trusion at one pole and exhibits glidingmotility in the direction of the protrusion (16–18). The average speed is 2.0 to 4.5 m/s, or three to seven times the length of the cell per second, exerting a force of up to 27 pN (7, 20, 23). This motility, combined with th