Extended Data Fig. 6: Strain displacement dynamics in the absence of supplemented sorbitol, and population dynamics in the presence of sorbitol when the invader has colicin K, related to Fig. 2.
From: Strain displacement in microbiomes via ecological competition
A-H) Ecological invasion experiments using the scheme in Fig. 2a but without 4% sorbitol. Media is inoculated with either wild-type (WT) E. coli or an isogenic ∆srlAEB mutant (all resident strains kanamycin resistant; blue) that cannot use sorbitol. 8h later, a WT E. coli with or without colicin E2 or K is inoculated (all invader strains chloramphenicol resistant; red). Populations are enumerated using selective plating. Lines connect medians, dotted lines indicate detection limits from selective plating. A-B) The invader strain does not contain a toxin (E. coli WT; hollow red circles; N=9 biological replicates from independent experiments). C-D) The invader has colicin E2 (N=5 biological replicates from independent experiments). E-F) The invader has colicin K (N=5 biological replicates from independent experiments). The resident is WT E. coli (hollow blue circles) in panel A, C, E and an isogenic ∆srlAEB mutant (grey-filled blue circles) that cannot use sorbitol in panel B, D, F. G-H) Same experiment as panel A-F, but only the endpoint values at 72h are plotted for both the invader (panel G) and the resident (panel H). See above for sample sizes. Two-tailed Mann-Whitney U tests are used to compare population sizes when the invader does not use a toxin to when the invader uses either colicin E2 or colicin K. Black lines indicate medians, dotted lines indicate the detection limits of selective plating. I-J) Ecological invasion experiments using the scheme in Fig. 2a. Media is inoculated with either wild-type (WT) E. coli (panel I; hollow blue circles) or an isogenic ∆srlAEB mutant (panel J; blue circles with grey fill; all resident strains kanamycin resistant) that cannot use sorbitol. 8h later, a WT E. coli with colicin K is inoculated (chloramphenicol resistant; red circles with black fill). Populations are enumerated using selective plating. Lines connect medians, dotted lines indicate detection limits from selective plating.
