Ation between the points, with added points added as the contour becomes longer to sustain roughly the initial spacing. We checked that dt along with the spacing among points along s were sufficiently tiny for numerical integration. To calculate whole-cell shapes in Fig. 3A, steady-state tip shapes have been joined to a cylindrical middle section along with the length of that section was selected to offer constant volume.two. Solutions Connected to Model for Shape Upkeep by Growth Zones, Landmarks, and Microtubules (Fig. 6)Cell PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/20166463 boundary. The outline with the cell border is modeled as a series of discrete points (see Fig. 6E) as described in Solutions section 1 for the axisymmetric growth model. Right here CatmullRomm splines have been used for the interpolation through contour resegmentation. This alleviates an impact exactly where repeated linear resegmentation erodes the contour, specially as dt becomes smaller. Discretization with the cell boundary. For the simulation to accurately represent the continuum model, the number of points along the cell boundary needs to be chosen so that the distance in between points is a lot smaller sized than the inverse of any curvature along the contour representing the cell outline. Thus the initial variety of beads n is selected by:Methods 1. Strategies Related to Model for Remodeling beneath Turgor Stress (Fig. two)Evolution of tip shape as function of growth-factor signal L(s). The differential equations described by Eq. (four) can berearranged to provide a differential equation for vt (as in [25]): Lvt ks cos w ks { vt js { jh : Ls kh kh r 4n 100:Pinit =min LIMKI 3 chemical information stencil ,kinit 8The geometric relations sin w rkh (see Fig. 1) and ks Lw=Ls allow this to be simplified: Lvt Lw ks {cot wvt js { jh : Ls kh Ls 5The left-hand side is sin wL(vt csc w)=Ls, so the expression can be written: L t csc wks csc w js { jh : kh Ls 6Adding the boundary condition vt (0) 0, which is imposed by axisymmetry, the system admits the following solution:PLOS Computational Biology | www.ploscompbiol.orgwhere Pinit is the length of the perimeter at initialization, kstencil is the curvature at the tip of the stencil, and kinit is the curvature at the tip at initialization. Growth stencil (Fig. 6E). For the model of Fig. 6, we import a tip outline from the three-dimensional model. This is defined as the intersection of the three-dimensional outline with any plane that includes the axis of symmetry of the three-dimensional outline, trimmed back at the section of the outline where the cell becomes cylindrical. A Gaussian growth-factor profile was used to generate this outline, which can then be scaled to match the width parameter of a growth zone. The axis of symmetry of this stencil is then aligned to the normal vector at its position on the contour representing the cell outline. For growth, the tip is moved along this normal vector by v dt, where v is the magnitude of the growth velocity vector, and points along the contour representing the cell outline are moved towards points that are the same distance along the stencil. Points on the contour representing the cell outline do not move if that movement would be inward (if the inner product of the normal vector with the direction to the corresponding pointModel of Fission Yeast Cell Shapeon the stencil is negative), and only move a maximum distance of 2 v dt (12s/S) where s is the distance from the growth zone and S is the maximum distance along the growth stencil. This prevents discontinuities in the contour representing th.
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