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Team:Paris Bettencourt/GFP microscopy Dubey Ben-Yehuda
From 2011.igem.org
Figure 1. Visualizing a Molecular Gradient between Neighboring B. subtilis Cells
(A) PY79 (gfp -) and SB444 (gfp+) cells were grown side by side on an LB agar plate at 37° C and visualized by fluorescence microscopy 15 hr after plating, when small colonies were visible. The dashed line indicates the border between the two populations. (a) Phase contrast image (blue). (b) GFP fluorescence image (green). (c) Overlay of phase and GFP fluorescence images. The scale bar represents 10 mm.
(B) Average fluorescence intensity of the gfp- population (as indicated in Aa) as a function of the distance from the gfp+ population. The gfp- region was divided into identical sub-regions and the average fluorescence signal was defined in arbitrary units (AU).
(C) Exponentially growing PY79 (gfp -) and SB444 (gfp+) cells were mixed, plated on an LB agarose pad, and incubated in a temperature controlled chamber at 37° C. Cells were visualized by time-lapse fluorescence microscopy and phase contrast (blue) and fluorescence (green) images collected at 10 min intervals. Select overlay images are shown from the following time points: (a) t0 min, (b) t30 min, and (c) t60 min. Each pair of colored arrows (red and yellow) indicates different locations where transfer of fluorescent molecules between neighboring cells is increasing over time. Larger fields of the same region are shown in Figure S1. The scale bar represents 1 mm.
(D) Average fluorescence intensity of the gfp - cells as a function of their distance from the gfp+ cells at t0 min (light blue bars) and at t60 min (dark blue bars) of the co- incubation experiment as described in (C) . No detectible signal was measured when cells were located beyond 1mm at t0 min. Average fluorescence signal is expressed in arbitrary units (AU). Error bars represent standard deviation (SD) of the mean fluorescence signal calculated from at least 40 cells located at the indicated distance. Shown is a representative experiment out of three independent biological repeats.
Extract from the Dubey and Ben-Yehuda article [1]
