Buckling of appendage drives tiny two-point turn
K. Son et al/Nature Physics
When headed the wrong way, some bacteria turn by letting their propellers flop.
The newly discovered turning mechanism explains how a marine bacterium can control its direction using only a single flagellum, a stiff, rotating appendage that propels the cell forward. Turning depends on a mechanical characteristic that engineers might consider a failure if the flagellum were human-made: the tendency of flexible materials to buckle under pressure.