Fast-Moving Bacteria Self-Organize into Active Two-Dimensional Crystals of Rotating Cells

Condensed Matter journal club

Fast-Moving Bacteria Self-Organize into Active Two-Dimensional Crystals of Rotating Cells

  • Event time: 11:30am
  • Event date: 16th October 2015
  • Speaker: (School of Physics & Astronomy, University of Edinburgh)
  • Location: Room 2511,

Event details

Abstract

We investigate a new form of collective dynamics displayed by Thiovulum majus, one of the fastest swimming bacteria known. Cells spontaneously organize on a surface into a visually striking two dimensional hexagonal lattice of rotating cells. As each constituent cell rotates its flagella, it creates a tornadolike flow that pulls neighboring cells towards and around it. As cells rotate against their neighbors, they exert forces on one another, causing the crystal to rotate and cells to reorganize. We show how these dynamics arise from hydrodynamic and steric interactions between cells.We derive the equations of motion for a crystal, show that this model explains several aspects of the observed dynamics, and discuss the stability of these active crystals.
PRL 114 article 158102 (2015)
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Authors

Alexander P. Petroff, Xiao-Lun Wu, Albert Libchaber