Details about the videos : - "Movie1.avi" => Fluorescent polystyrene beads (10 microns of diameter and surface fraction 0.12) in a suspension of Burkholderia contaminans (not fluorescent) at OD=5. The movie is taken in YFP fluorescence in 2.5X (5.3x5.3mm). It takes place in the middle of a chamber sealed by PDMS (310 microns of height), where bacteria are swimming freely. Duration of the movie 1H00 (2 frame per min). - "Movie2.avi" => Fluorescent polystyrene beads (5 microns of diameter and surface fraction 0.6) in a suspension of Burkholderia contaminans (not fluorescent) at OD=5. The movie is taken in YFP fluorescence in 2.5X (5.3x5.3mm), 10 minutes after the sealing of the chamber. It takes place in the middle of a chamber sealed by PDMS (310 microns of height), where bacteria are swimming freely. The movie is in real time (10fps). - "Movie3.avi" => Same as "Movie2.avi" but the image size is (1.8x1.8mm). - "Movie4.avi" => Fluorescent polystyrene beads (5 microns of diameter and surface fraction 0.6) in a suspension of Burkholderia contaminans (not fluorescent) at OD=5. The movie is taken in phase-contrast in 10X (0.13x0.13mm). It takes place in the middle of a chamber sealed by PDMS (310 microns of height), where bacteria are swimming freely. The movie is in real time (10 fps).