Gliding in Cytophaga
Cells of Cytophaga sp. strain U67 move over glass by an unknown mechanism at about 2 µm/s. If latex beads are added, they move lengthwise along the cell surface (whether the cell is on glass or not) at about the same speed. The beads move in either direction, passing each other going in opposite directions, even if on the same side of the cell. The first movie shows this phenomenon with beads 0.56 µm dia. When a large aggregate (or blob) of smaller beads (0.13 µm dia.) moves along a cell, it can complete a full cycle up and back, returning to its original position and orientation. The second movie shows this phenomenon with a cell in suspension. We concluded that proteins that bind to glass or latex beads are driven along tracks mounted lengthwise upon the peptidoglycan layer of the cell wall. Since the beads moved longitudinally along the cell surface rather than circumferentially and bent cells moved along glass without difficulty, we concluded that gliding did not require rotation about the cell's long axis. A similar mechanism now appears likely for adventurous motility in Myxococcus xanthus; see Mignot et al (2007).
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