Fig. 3
Experimentally observed spatial segregation of bacterial populations in a micrometric pore network. The facultative anaerobic Pseudomonas veronii strain 1YdBTEX2-mChe is tagged with the mCherry fluorescent protein and shown with pseudo-color magenta, and the obligate aerobic Pseudomonas putida strain KT2440-gfp is tagged with the eGFP fluorescent protein and shown with pseudo-color cyan. The two species were mixed 1:1 in suspension and inoculated to the central port (total of ≈500 cells per species) of a pore network with a carbon source (citrate) located at the center and oxygen diffusing from the peripheral ports. Both species were able to disperse through the pore network by flagellated motility. The exemplary overlay fluorescence image (top) shows the distribution of the two bacterial populations in a transect across the 100% connected pore network (see inset) 1 week after inoculation (image contrast and brightness were enhanced for better visualization of the bacterial populations). The scale bar represents 500 μm. The two close-up images show individual bacterial cells within one microscopy image, as used for digital image analysis and cell counting (each scale bar represents 40 μm)
