Figure 4

Active chemotaxis enables DNA messaging across centimeter lengths. (a) Bacterial chemotaxis using swim plates allows for interaction and messaging among sender and receiver cells. Three cases are presented: “non-motile” using non-motile sender and receiver cells; “pick-up” using non-motile sender cells but motile receiver cells and; and, “rendezvous” using motile sender and receiver cells. Stem plots give the measured less background absorbance (solid circles with stems) for well-mixed liquid cultures inoculated from plugs sampled in a equal spaced pattern across swim plates and cultivated with selection for sender cells (ampicillin), the messaging phagemid (chloramphenicol), or message transmission (both antibiotics). Distance from plate centers as noted; x-axes are consistent across each stem plot and cognate merged fluorescent / bright field plate photograph. (b) Active transmission of a DNA message across a 7 cm gap. Three representative photographs (upper row) merging RFP and GFP fluorescence from cells obtained directly from the merge region of a “rendezvous” swim plate; corresponding bright field images (lower row). Arrows indicate yellow cells expressing both reporters. (c) Merged multi-channel fluorescent micrographs of cells grown in replicate well-mixed liquid cultures inoculated with one sample taken from the merge zone of the rendezvous swim plate and cultivated under antibiotic selections, as noted.