Figure 3
Periodic shaking of gfp-expressing bacteria in a microplate reader alters their spatial distribution. (A) When gfp-expressing bacteria were grown in medium with 0% agar, bacteria were spread amongst the well. When bacteria were grown in medium with 0.2% or 0.4% agar, the majority of bacteria were confined to a central cluster at the initial point of inoculation. (B) Representative images of gfp-expressing bacteria during periodic shaking of the microplate. The central cluster is indicated with a white arrow. For panels B, C and E, images taken at 24 hours. (C) Representative images of bacteria in 0% agar with increased magnification. (D) The volume of clustered gfp-expressing bacteria. In all agar densities, the volume of bacteria was highest at an intermediate shaking frequency (3/hr). Inset: Data expanded to show trend in medium with 0% agar. p  < 0.048 when 1/hr and 12/hr are compared to 3/hr demonstrating significance in biphasic trend (one-tailed t-test). Volume calculated as described in Methods. SD from a minimum of three biological replicates. (E) Representative images of bacteria outside of the central cluster. Bacteria were scattered, less numerous and formed smaller colonies.
