458: Slimy Cells Stop Sinking

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


 



Takeaways




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.



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com. Thanks for listening!


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