1. Colony and microcolony imaging of cargo transport.
Colony and microcolony imaging of cargo transport. (a) A periodically expanding colony composed of swarming P. vortex and Ampr E. coli cargo imaged after incubation for 72 h at 37°C on a 14-cm-diameter MH agar plate with 200 µg ml−1 Amp. The plate was stained with Coomassie blue to enhance contrast. (b) Imaging by fluorescence microscopy of two moving peripheral colonies (rotating and moving progressively outwards from the inoculation point, in an experiment identical to that shown in panel a), using hexidium iodide to identify P. vortex (red) and GFP expression for E. coli (green). (c) Imaging by fluorescence microscopy of microcolony transport of a Ctxr strain of Enterobacter aerogenes GA2 (stained by Syto 9 [green]) by P. vortex (stained by hexidium iodide [red]) over agar containing 3 µg ml−1 Ctx. The arrow shows the overall direction of transport at a rate of ~3 mm h−1. (d) Transport of a consortium of P. vortex and Ampr E. coli over an MH agar plate with a barrier of Amp created by four Neosensitabs (see Fig. S2 in the supplemental material). Imaging is of E. coli via a blue light LED to visualize GFP expressed by the cargo strain. The scale bar in panel c (300 μm) corresponds to 3.8 cm (panel a), 200 µm (panel b images), and 1.9 cm for the cell in panel d.
Alin Finkelshtein et al. mBio 2015; doi: /mBio