Microbubbles reveal chiral fluid flows in bacterial swarms.
Proc Natl Acad Sci U S A
; 108(10): 4147-51, 2011 Mar 08.
Article
em En
| MEDLINE
| ID: mdl-21300887
ABSTRACT
Flagellated bacteria can swim within a thin film of fluid that coats a solid surface, such as agar; this is a means for colony expansion known as swarming. We found that micrometer-sized bubbles make excellent tracers for the motion of this fluid. The microbubbles form explosively when small aliquots of an aqueous suspension of droplets of a water-insoluble surfactant (Span 83) are placed on the agar ahead of a swarm, as the water is absorbed by the agar and the droplets are exposed to air. Using these bubbles, we discovered an extensive stream (or river) of swarm fluid flowing clockwise along the leading edge of an Escherichia coli swarm, at speeds of order 10 µm/s, about three times faster than the swarm expansion. The flow is generated by the action of counterclockwise rotating flagella of cells stuck to the substratum, which drives fluid clockwise around isolated cells (when viewed from above), counterclockwise between cells in dilute arrays, and clockwise in front of cells at the swarm edge. The river provides an avenue for long-range communication in the swarming colony, ideally suited for secretory vesicles that diffuse poorly. These findings broaden our understanding of swarming dynamics and have implications for the engineering of bacterial-driven microfluidic devices.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Escherichia coli
Idioma:
En
Revista:
Proc Natl Acad Sci U S A
Ano de publicação:
2011
Tipo de documento:
Article
País de afiliação:
Estados Unidos