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. Author manuscript; available in PMC: 2020 Sep 25.
Published in final edited form as: Cell Syst. 2019 Sep 4;9(3):229–242.e4. doi: 10.1016/j.cels.2019.06.008

Figure 3. The molecular composition of the environment shapes the interaction network of a three-member consortium.

Figure 3.

(a) Schematic of the expected microbial interaction network of a three-member consortium consisting of RFP-labeled E. coli (EC WT), CFP-labeled E. coli methionine auxotroph (EC Met-), and YFP-labeled S. Typhimurium deficient in lactose metabolism (ST Lac*) in lactose minimal media lacking supplemented methionine (Table S1, E3). Secreted carbon byproducts (acetate) and methionine are represented by a triangle and rectangle, respectively. Node colors and green arrows denote the type of fluorescent reporter and positive interactions, respectively. (b) Schematic of the expected microbial interaction network in lactose minimal media supplemented with methionine (Table S1, E4). (c) Schematic of the expected microbial interaction network in glucose minimal media lacking supplemented methionine (Table S1, E5). (d) Schematic of the expected microbial interaction network in glucose minimal media supplemented with methionine (Table S1, E6). (e) Cell count distributions in lactose minimal media for EC WT (top), ST Lac* (middle) or EC Met- (bottom). The black line represents the mean and the error bars denote the bootstrapped 95% confidence intervals for the mean. The gray horizontal bars indicate a statistically significant difference (p < 0.05, Table S2) based on the Mann-Whitney U test. (f) Cell count distributions in lactose minimal media supplemented with methionine for EC WT (top), ST Lac* (middle) or EC Met- (bottom). (g) Cell count distributions in glucose minimal media for EC WT (top), ST Lac* (middle) or EC Met- (bottom). (h) Cell count distributions of EC WT (top), ST Lac* (middle) or EC Met- (bottom) in glucose minimal media supplemented with methionine. (i) Inferred interaction network in lactose minimal media lacking supplemented methionine. The edge width is proportional to the log2 ratio of the average cell count in the presence of a partner to the average cell count in the absence of the partner. Node size is proportional to the average cell count of each strain grown in isolation. (j) Inferred network in lactose minimal media supplemented with methionine. (k) Inferred interaction network in glucose minimal media lacking supplemented methionine. (l) Inferred interaction network in glucose minimal media supplemented with methionine.