dictyNews Electronic Edition Volume 31, number 10 September 26, 2008 Please submit abstracts of your papers as soon as they have been accepted for publication by sending them to dicty@northwestern.edu or by using the form at http://dictybase.org/db/cgi-bin/dictyBase/abstract_submit. Upon publication of your paper, please send strains and plamids to the Dicty Stock Center. For more information see http://dictybase.org/StockCenter/Deposit.html. Back issues of dictyNews, the Dicty Reference database and other useful information is available at dictyBase - http://dictybase.org. ========= Abstracts ========= A 3-D model used to explore how cell adhesion and stiffness affect cell sorting and movement in multicellular systems Eirikur Palsson Department of Biology, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6 Journal of Theoretical Biology Volume 254, Issue 1, 7 September 2008, Pages 1-13 A three-dimensional mathematical model is used to determine the effects of adhesion and cell signalling on cell movements during the aggregation and slug stages of Dictyostelium discoideum (Dd) and to visualize cell sorting. The building blocks of the model are individual deformable ellipsoidal cells, where movement depends on internal parameter state (cell size and stiffness) and on external cues from the neighboring cells, extracellular matrix, and chemical signals. Cell movement and deformation are calculated from equations of motion using the total force acting on each cell, ensuring that forces are balanced. The simulations show that the sorting patterns of prestalk and prespore cells, emerging during the slug stage, depend critically on the type of cell adhesion and not just on chemotactic differences between cells. This occurs because cell size and stiffness can prevent the otherwise faster cells from passing the slower cells. The patterns are distinctively different when the prestalk cells are more or less adhesive than the prespore cells. These simulations suggest that sorting is not solely due to differential chemotaxis, and that differences in both adhesion strength and type between different cell types play a very significant role, both in Dictyostelium and other systems. Keywords: Dictyostelium; Differential cell adhesion; Pattern formation; Ellipsoidal cells; Deformable cells; Prestalk Submitted by: Eirikur Palsson [epalsson@sfu.ca] ============================================================== [End dictyNews, volume 31, number 10]