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SUMMARY:Internal stresses show elastic behaviour of a dynamic cell sheet -
  Stephanie Höhn (Cambridge)
DTSTART:20200206T130000Z
DTEND:20200206T140000Z
UID:TALK138904@talks.cam.ac.uk
CONTACT:George Fortune
DESCRIPTION:Living tissues are intelligent materials that can change their
  mechanical properties while they develop. In spite of extensive studies\,
  we are only just beginning to understand these dynamic properties and the
 ir role in tissue development. The simple bauplan of Volvox embryos is uni
 quely suited for studies on morphogenesis. V. globator embryos consist of 
 a spherical cellular monolayer which undergoes a process of inversion to e
 xpose the flagella [1-3]. During this process the posterior hemisphere shr
 inks while its positive Gaussian curvature increases. But are both\, the d
 ecrease in surface area and the increase in curvature the result of active
  cellular changes? What kind of forces the cells generate can be inferred 
 from the internal stresses of the dynamic cell sheet. Another question is 
 whether the tissue yields or adapts to the internal stresses over time\, a
  behaviour that has been observed in numerous biological tissues. These qu
 estions were addressed through a combination of laser cutting experiments 
 and theoretical modelling. The results suggest that the shrinking of the p
 osterior hemisphere is caused by active tissue contraction which results i
 n a passive change in curvature. Furthermore\, the dynamic cell sheet rema
 ins under stress throughout inversion which indicates the lack of creep-be
 haviour and is consistent with a purely elastic nature of the cell sheet.\
 n \n[1] Höhn S and Hallmann A. BMC Biology 9\, 89 (2011).\n\n[2] Höhn S\
 , Honerkamp-Smith AR\, Haas PA\, Khuc Trong P\, and Goldstein RE. Physical
  Review Letters 114\, 178101 (2015).\n\n[3] Haas PA\, Höhn S\, Honerkamp-
 Smith AR\, Kirkegaard JB\, and Goldstein RE. PLOS Biology 16\, e2005536 (2
 018).\n
LOCATION:MR11\, Centre for Mathematical Sciences\, Wilberforce Road\, Camb
 ridge
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