Movies of swimming motility

Escherichia coli

Rhodobacter sphaeroides


Movies of swarming motility

Escherichia coli swarm

Salmonella typhmurium swarm

Serratia marcescens swarm

Movies of gliding motility


Mycoplasma mobile

Flavobacterium johnsoniae

Movies of Twitching motility

Pseudomonas aeruginosa

Other movies

Tethered bacteria

Escherichia coli patterns

Carpets and microchannels

Miscellaneous movies

Marvels of Bacterial Behavior - History & Physics of Bacterial Motion

Rowland Institute         Harvard University

Swarming Salmonella typhimurium

When grown on soft agar (0.5-0.8%) and a rich medium, cells of Salmonella typhimurium (and other Gram-negative bacteria) elongate, produce more flagella, and move over the surface of the agar in a coordinated manner. Lipopolysaccharide (slime) appears to be important as a wetting agent. The chemotaxis system is required, but the cells need not respond to specific attractants or repellents. As you will see in the movies, the cells swirl about in rafts or packs. At the edge of the swarm they form a monolayer. At the very edge, cells are nearly stationary. Farther back, closer to the point of inoculation, cells pile up in multilayers and are very active. The videos were made in phase contrast.


Swarming at 2 hours incubation, center

Swarming at 2 hours incubation, edge

Swarming at 4 hours incubation, center

Swarming at 4 hours incubation, edge


Harshey, R. M. Bees aren't the only ones: swarming in Gram-negative bacteria. Mol. Microbiol. 13, 389-394 (1994).

We would like to thank Rasika Harshey for her help in creating these movies.