[ODP-035] Imaging of amphitrichous flagellar rotations in Magnetospirillum magneticum AMB-1
Magnetotactic bacteria (MTB) swim along the geomagnetic field for facilitating their search for microaerobic environment. However, the detailed flagellar rotation of MTB during magneto-aerotaxis is not observed. In this study, we imaged individual polar flagellar rotations of swimming Magnetospirillum magneticum AMB-1, an amphitrichous magnetotactic spirillum, in microaerobic environment. We placed the cells in a chamber slide with an oxygen gradient and observed fluorescently labelled flagellar motility using HILO fluorescence microscopy. The lagging flagellum showed counter clockwise rotation during swimming, while the leading flagellum showed clockwise rotation. AMB-1 cells changed the swimming direction by reversing both flagellar rotation simultaneously at the edge of the oxyic-anoxyic transition zone. At first the leading flagellum was inversed then the lagging flagellum was. As the result, the cell switched the swimming direction. The lag time of between the leading and lagging flagella inversions was less than 200 ms. This means that AMB-1 has molecular mechanism that regulate asymmetric flagellar motility at both cell poles simultaneously.