Figure 4.

Expansion patterns at the biofilm-agar interface. (A) Forces generated by the biofilm as reflected in the deformation of a droplet consisting of fluorescent microspheres (2.5 µL). Days 1-3 are shown, left to right. Scale bars 1000 μm. (B) Pathway of microspheres in a droplet caught in a channel formed by a 50% nutrient-depleted macrocolony. Scale bars 500 μm. Rightmost image is a close up of the formed channels—scale bar 200 μm. (C) Different modes of deformation found at the contact surface—(a) segmented, (b) filamentous, (c) unidirectional, (d) multidirectional, (e) turbulent. The images in (A,C) are representative of eight experiments. Scale bar 1000 μm.