XB-IMG-124741
Xenbase Image ID: 124741
Figure 13. Impact of changes in areas of cross section on equilibration kinetics:
predictions from the diffusion model. (A) Idealized cells with the
geometry of frog or mouse rods and for an idealized ciliated cell for
which equilibration time courses were modeled by solving Eqs. 13–15. The rod ISs or the
cell body (CB) were initially uniformly filled with diffusing substance
(black), and the OS and cilia were empty. Equilibration after some
period of time is indicated by uniform gray in all compartments. Arrow
thickness denotes relative speed of equilibration (see B–D). (B)
Time courses of equilibration into rod OS compartments. The lengths of
each compartment were: IS, 5 µm; CC, 0.8 µm; OS, 25
µm. The CC had the same diameter in all cases, 0.4 µm
(average diameter from Table
I). A range of rod IS and OS diameters were modeled, including 7
µm, representative of frog rods, and 1.4 µm, based on the
most recent measurements of mouse rod dimensions (Daniele et al., 2005). In all cases,
DIS = 5 µm2
s−1, DCC = 2
µm2 s−1, and
DOS = 0.1 µm2
s−1. The mass in the OS normalized to the
equilibrated OS mass is plotted. (C) Dependence of the
T1/2 of equilibration on the ratio of CC
and IS–OS radii. Line is drawn through the points. (D) Time
course of cilium equilibration. Ciliated cells (10-µm long cell
body and 5 µm in diameter, possessing a cilium 0.4 µm in
diameter and varied length) were modeled. The mass of the diffusing
substance in the cilium normalized to the equilibrated mass is plotted
for cilia of indicated length. Image published in: Calvert PD et al. (2010) © 2010 Calvert et al. This image is reproduced with permission of the journal and the copyright holder. This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike license Larger Image Printer Friendly View |