| Value |
17.6
µm^2/s
Range: ±1.8 µm^2/s
|
| Organism |
Fruit fly Drosophila melanogaster |
| Reference |
Gregor T, Bialek W, de Ruyter van Steveninck RR, Tank DW, Wieschaus EF. Diffusion and scaling during early embryonic pattern formation. Proc Natl Acad Sci U S A. 2005 Dec 20 102(51):18403-7. p.18405 tables 1 & 2PubMed ID16352710
|
| Method |
Fluorescent dextran injected into Drosophila embryo, confocal imaging, and fitting with 3D diffusion model |
| Comments |
P.18405 left column 2nd paragraph: "If random molecular movement is due to Brownian motion (passive diffusion), then it is governed by the Stokes–Einstein relationship: diffusion coefficients decrease inversely with increasing molecular radius. To test this relationship, [investigators] measured diffusion constants for dextran molecules of four different nominal molecular masses (Table 1)." P.18405 left column bottom paragraph: "Although Bcd is conserved across >100 million years of dipteran evolution (refs 17), the eggs of closely related species vary over at least a factor of five in length (Table 2)." P.18406 left column bottom paragraph: "Mechanisms of Scaling. How is scaling of the Bicoid gradient achieved? In the simplest model, the length constant λ =(Dτ)^0.5, where τ is the protein lifetime (see Methods). The active contribution to the effective diffusion constant D that [investigators] have identified above raises the possibility that total effective diffusive transport itself can be adjusted across species. To test this possibility, [they] injected 40-kDa dextran molecules into eggs of D. busckii, L. sericata, and Calliphora vicina. Table 2 shows a summary of [their] results: the diffusion constants in the different species vary only slightly. There is a tendency for increased diffusivity and decreased variability with increasing egg length, but the increase does not scale with egg size."(N=20). See BNID 100193 |
| Entered by |
Lea Goentoro |
| ID |
100198 |