Mastigonemes on cell swimming behavior and viscosity sensitivity. (A) Real-time images of free-cell swimming showed the more pronounced rotational behavior exhibited by mst1 cells compared to wild-type cells (cc125 and cw15). The line in the figure represents the line connecting the center of the two flagella to the center of the cell (bar = 5 μm). (B) Gravitaxis difference among cc125, cw15, and mst1 during different time points. Each group consists of three batches of cells, and each experiment consists of three tubes repeat. Error bars represent the standard deviations for the means.