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SUMMARY:Buckling instabilities in chaining bacterial colonies  (talk held 
 in Department of Engineering not the INI) - Aidan Brown (University of Edi
 nburgh)
DTSTART:20231123T140000Z
DTEND:20231123T150000Z
UID:TALK208861@talks.cam.ac.uk
DESCRIPTION:Bacteria frequently grow together as colonies. Large\, complex
  colonies\, known as `biofilms&rsquo\;\, are often multi-species and exhib
 it cooperative behaviour reminiscent of multicellular organisms\, such as 
 signalling and controlled cell death. However\, even at the early stages\,
  colonies exhibit many different structures and morphologies\, which are c
 ontrolled by a dynamic interplay between cell growth and division\, the sh
 ape of cells and the physical interactions between them. One type of inter
 action\, called `chaining&rsquo\;\, consists of the maintenance of a physi
 cal\, usually protein\, link between sister cells following division. Chai
 ning is common in many bacterial species\, but is particularly well known 
 in the rod-shaped Bacillus subtilis\, where buckling of single chains of b
 acteria leads to convoluted\, open colonies with many pores and channels. 
 This contrasts with the structure of non-chaining bacteria\, such as Esche
 richia coli\, which typically fracture into multiple small\, aligned domai
 ns. Here\, I will present 2D discrete-element simulations of growing bacte
 rial colonies\, where we continuously tune the probability and strength of
  chaining between daughter cells. At the extremes\, we reproduce the behav
 iour of B. subtilis and E. coli -like colonies\, but for intermediate valu
 es of the chaining parameters\, we identify a novel state\, where the whol
 e colony buckles collectively. A toy\, lattice model reproduces the shape 
 of the transition between the `aligned domains&rsquo\; and `collective buc
 kling&rsquo\; states\, and enables us to show that the impact of chaining 
 is to modify the rate and probability with which these different mechanism
 s occur.\n&nbsp\;\nDate and venue: Thursday 23 November 2023\, 14:00-15:00
 \, LR4\, Baker Building\; or via Zoom. (Please check with the program orga
 nisers)\n&nbsp\;\n&nbsp\;
LOCATION:External
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