Figure 8.

Dispersal of a RIF^R strain of P. vortex within extended colonies of the RIF^S strain. All graphs plot the average migration distance of the RIF^R strain against time (± SD) on MH agar (0.3% w/v in panels A-C or 1.5% w/v agar in panels D-F) when inoculated into a RIF^S colony and incubated at 37°C. A. Inoculation of the RIF^R strain at the edge of the initial ring, 0.5 mm from center of the dish at the same time as the RIF^S strain (■) and 5 h after (□). B. Inoculation of actively swarming 30 mm radius RIF^S colonies at the outer edge of the colony with the RIF^R strain. (■) Outwards migration of RIF^R subsequently tracked and limited to 22.5 mm by the edge of the Petri dish. (□) Inwards migration. C. Inoculation of Petri-dish-wide RIF^S colonies at one edge with RIF^R strain. (□) Immediately after swarming RIF^S cells reached edge of Petri dish, (■) 12 h later (▲) 36 h later. D. As (A) except on1.5% (w/v) agar. E. As (B) but on 1.5% (w/v) agar. F. As (C) but on 1.5% (w/v) agar.