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SUMMARY:E. coli chemotaxis\, free and near surface swimming - Christian Es
 parza López (University of Cambridge)
DTSTART:20190321T130000Z
DTEND:20190321T140000Z
UID:TALK121801@talks.cam.ac.uk
CONTACT:Anne Herrmann
DESCRIPTION:Swimming bacteria such as E. coli are known to be able to expl
 ore their environment by performing a random walk. It is also know that th
 ey can follow chemical queues and drift up or down chemical concentration 
 gradients. This movement in response to a chemical stimulus is known as ch
 emotaxis. E. coli performs chemotaxis by increasing the time that they spe
 nd swimming up or down the gradient. This strategy is know to be efficient
  when the bacterium is swimming far away from any boundary\, however most 
 bacteria spend their life in confined environments and hydrodynamic intera
 ctions may decrease the effectiveness of this strategy. In this talk I wil
 l show that chemotaxis of E. coli is hindered when swimming near to a surf
 ace due to the effect of hydrodynamic interactions. First I will revisit t
 he problem of diffusion of circle swimmer using an isotropic random walk w
 ith circular trajectories\, interrupted by changes in direction. Chemotaxi
 s is added by allowing the arc length of the trajectories to depend on a c
 hemical concentration gradient and I will show that in the limit of shallo
 w gradients\, it is possible to obtain negative chemotaxis\, that is drift
  away from an attractant.\n
LOCATION:MR11\, Centre for Mathematical Sciences\, Wilberforce Road\, Camb
 ridge
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