||Chinese hamster ovary (CHO)
||Elowitz MB, Surette MG, Wolf PE, Stock J, Leibler S. (1997), Photo-activation turns green fluorescent protein red, Curr. Biol, 7 (10) p. 811 right column 3rd paragraphPubMed ID9368766
||Swaminathan R, Hoang CP, Verkman AS. Photobleaching recovery and anisotropy decay of green fluorescent protein GFP-S65T in solution and cells: cytoplasmic viscosity probed by green fluorescent protein translational and rotational diffusion. Biophys J. 1997 Apr72(4):1900-7.PubMed ID9083693
||Primary source (abstract):"The green fluorescent protein (GFP) was used as a noninvasive probe to quantify the rheological properties of cell cytoplasm."
||"These measurements show that GFP diffusion in the cytoplasm of E. coli strain DH5a is twelve times slower than in water (where D = 87 µm^2/sec) and almost four times slower than the value reported for eukaryotic cytoplasm (D = 27 µm^2/sec in CHO cells) [primary source]. Specifically, from photoactivation experiments, [investigators] obtained an average diffusion constant Dact = 6.7 ±1.6 µm^2/sec, while photobleaching gave [them] Dbleach = 6.0 ±1.0 µm^2/sec (n = 19 cells). The average ratio of Dact to Dbleach on the same cell was 1.1 ±0.1 ( Figure 3, bottom graph). It is possible to photodamage cells significantly by photobleaching GFP with high-intensity illumination. The photoactivation method has the advantage over photobleaching of requiring significantly less energy (a factor of 10 in these experiments). No phototoxicity was observed in [their] experiments (data not shown)." Primary source (abstract) says that relative viscosity of cytoplasm (vs. water) is 3.2. Dividing diffusion coefficient of GFP in water (87µm^2/sec, BNID 100301) by 3.2 gives 27µm^2/sec