File:Magneto-Chemotaxis-in-Sediment-First-Insights-pone.0102810.s004.ogv

English: In-field tactile response of M. bavaricum when colliding with sediment particles. Hanging drop assay prepared with higher sediment concentration for observing interactions of M. bavaricum cells with particles. The magnetic field points to the right. Tactile responses can be seen on freely swimming cells coming from the left. Some cells briefly reverse their swimming direction upon colliding with sediment particles (e.g. large cell near the center at 00′03″, and large cell on the bottom after at 00′37″). Other cells engage a long-lasting series of swimming direction reversals, oscillating around a mean position in proximity of sediment particles. These behaviors are never observed in absence of sediment particles. The field direction is reversed at 00′46″. Most cells that have accumulated on the right drop edge cross the region occupied by sediment particles without changing their swimming behavior, as a demonstration that tactile responses are facultative. A large cells swimming to the left near the video bottom stops its motion abruptly after touching a sediment particle (00′47″).