Figure 5.

Three-dimensional growth patterning. a, Growth of bacteria in a sphere. An Amp-impregnated agar gel cylinder was placed in the center of a vial of solidifying soft agarose containing 300 μM IPTG, 30 μg/ml Tet and dilute RH01 cells. The vials were incubated at 37°C overnight and visible images acquired. b, Growth of bacteria in a layer. Amp and IPTG disc were placed top and bottom of soft agarose containing 30 μg/ml Tet and dilute RH01 cells. The top disc was placed off center to illustrate that growth depends on the resulting concentration gradients and not the distance from the surface. The vials were incubated at 37°C overnight and visible images acquired. The IPTG disc is not visible in these images.