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. Author manuscript; available in PMC: 2015 Feb 27.
Published in final edited form as: Nat Commun. 2014 May 7;5:3780. doi: 10.1038/ncomms4780

Figure 4. Measurement of vesicle diameter in live astrocytes by SIM.

Figure 4

(a) Diagram of an astrocytic vesicle loaded with LysoTracker DND-99 (red), expressing YSpH (green) and (b) the corresponding SIM image in a live astrocyte. Bar, 300 nm. (c) Fluorescence intensity profile of LysoTracker and YpH in the vesicle lumen along the line drawn in b. The dashed line indicates how the apparent diameter of a vesicle was determined, by measuring the FWHM of Gaussian curve of the red fluorophore. Note the intersection with Gaussian curve drawn on normalized intensity of the red fluorophore, marked with arrows. (d) The frequency distribution plot for apparent vesicle diameter, as defined in c. The mean value (mean±s.e.m.) of the apparent vesicle diameter is 305±3 nm (n =129 vesicles, 9 cells), measured by fitting a Gaussian curve of the form described in Equation 1 (R2 = 0.94; significantly different from zero, P<0.001; ANOVA).