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SUMMARY:Finite element modelling of growing microtubules - Michael Verhoek
 \, KCL
DTSTART:20060607T130000Z
DTEND:20060607T140000Z
UID:TALK4867@talks.cam.ac.uk
CONTACT:David MacKay
DESCRIPTION:Microtubules (MTs) are small hollow tubes that are formed insi
 de every\neukaryote cell\, and which help in preserving the cell's structu
 re\,\ninternal transport and cell division. Their dynamics show periods of
 \nslow growth with shorter periods of quick shrinkage in between.\n\nThe M
 T is made up of filaments that connect laterally to form a tube\, an\nener
 getically unfavourable construction for the MT. We propose a\nstructural c
 ap to relax this configuration\, by having a seam where the\nMT opens up t
 o form a sheet. We have modelled the sheet as a slab of\nmaterial that pre
 fers to bend longitudinally and be straight laterally\,\nusing a simple fi
 nite model. We found that a structure like this\, fixed\nat one side as a 
 circle\, has a minimal energy configuration in the shape\nof a sheet. Furt
 hermore\, we found that the configurational energy\ndifference of the whol
 e MT for the closure of a unit of the sheet will\nbe smaller for a long sh
 eet than for a shorter sheet.\n\nThe relation between sheet energy and its
  length is used in a\nthermodynamical simulation of the growth of the MT\,
  based on the\naddition and closure of dimers. This model gives\, dependin
 g on the value\nof the lateral contact energy\, a clear image of how the s
 heet length\nbehaves in time and sheds some light on how the shrinkage par
 t of MT\ndynamics might be explained.\n\n
LOCATION:Ryle Seminar Room\, Cavendish Laboratory
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