Fig. 3

Synthetic microbial communication: Two-cell communication links yield various communication topologies. a Illustration of minimal two-cell links. Cell 1 (c1) senses synthetic peptide through GPCR 1 (g1). Activation of g1 leads to secretion of peptide 2 (p2). p2 is sensed by cell 2 (c2) through GPCR 2 (g2). g2 activation is coupled to a fluorescent read-out. Signal transmission from c1 to c2 is assessed by recording transfer-functions using co-cultures of c1 and c2 and increasing amounts of p1. b Functional information transfer through all 56 links established from eight peptide-GPCR pairs. Eight GPCRs at the g1 position were coupled to secretion of the seven non-cognate peptides at the p2 position. Heatmaps show the fluorescence/OD₆₀₀ value of c2 after exposing c1 to increasing doses of p1. Supplementary Figures 16 and 17 list full data sets and references heat maps. c Overview of the implemented communication topologies. Gray nodes: cells are able to process one input (expressing one GPCR) giving one output (secreting one peptide). Blue nodes: cells are able to process two inputs (OR gates, expressing two GPCRs) giving one output (secreting one peptide). Orange nodes: cells constitutively secrete the peptide for the next clockwise neighbor, and report on ring closure via a fluorescent read-out upon receiving a peptide signal from the counter-clockwise neighbor. Red nodes: cells are able to receive a signal and respond via a fluorescent read-out. d Ring topologies with an increasing number of members were established. An interrupted ring, with one member dropped out, was used as the control. Measurements were performed in triplicate, and error bars represent standard deviations. The fold-change in fluorescence between the full-ring and the interrupted ring is indicated for each topology. e, f A three-yeast bus topology (e) and a six-yeast branched tree-topology (f) were implemented (panel c). Fluorescence was measured after induction with all possible combinations of the three input peptides (zero, one, two, or three peptides). The numbers above the bars indicate the fold-change in fluorescence over the no-peptide induction value. Measurements were performed in triplicate, error bars represent SD