Monday, July 19, 2021

458 - Slimy Cells Stop Sinking

Colonies of strains with
different floating strengths
By Kessler et al. 2021,
J Bacteriol 203(11):e00023-21
CC BY 4.0
This episode: Bacteria can resist the force of gravity in liquid culture by covering themselves with goopy sugar polymers like parachutes!

Download Episode (10.4 MB, 15.2 minutes)

Show notes:
Microbe of the episode: Brevicoryne brassicae virus

Put bacteria in a centrifuge, and most of the time you end up with a compact pellet of cells at the bottom of the tube, and mostly cell-free liquid above it. Bacteria do have ways to remain suspended in liquid, even without constant stirring or shaking of the container, but swimming, for example, consumes energy.

In this study, artificial selection allowed the discovery of bacteria that could resist centrifuging speeds up to 15000 times the force of gravity, remaining suspended in liquid instead of forming a pellet. Production of polysaccharide was important, but not sufficient; for the most resistance to sinking, bacteria had to attach the polysaccharide to their cell surface, to act as a sort of parachute.

Journal Paper:
Kessler NG, Caraballo Delgado DM, Shah NK, Dickinson JA, Moore SD. 2021. Exopolysaccharide Anchoring Creates an Extreme Resistance to Sedimentation. J Bacteriol 203(11):e00023-21.

Other interesting stories:

Post questions or comments here or email to Thanks for listening!

Subscribe: Apple Podcasts, Google Podcasts, Android, or RSS. Support the show at Patreon, or check out the show at Twitter or Facebook.

No comments:

Post a Comment