Movements of tethered Marine Bacterium with a Polar Flagellum
Xiao-Lun Wu (University of Pittsburgh)
Hydrodynamics of Swimming Microorganisms
Tue 9:00 - 10:30
Barus-Holley 191
Many marine bacteria have their flagella enclosed in a membrane that appears to be an extension of the membrane of the cell body. While the biological functions of the sheathed flagella have subjected to much speculation, how such membrane sheath affects bacterial swimming and propulsion is not known. Using a poly-lysine treated glass surface, we investigated motion of marine bacterium Vibrio alginolyticus that is tethered by its flagellum. It is found, surprisingly, that tethering does not impede a cell’s ability to propel its body, indicating that the flagellar core can rotate freely within the membrane sheath. We also found that the relative position of the cell body to the tethering point changes depending on the motor direction. During the CCW rotation, the cell body is extended along the surface whereas during the CW rotation, the cell body is oriented preferentially perpendicular to the surface. These behaviors appear to be qualitatively consistent with resistive force theoretical calculations and are potentially useful for studying bacterial motor switches.