Fig. 4: Metabolic interaction between the reuterin producer and degrader.
From: Plasmid-encoded toxin defence mediates mutualistic microbial interactions
a(i), Bar graph representing quantitative PCR analysis (16S rRNA gene) of mono- and co-cultures of L. reuteri (orange) with the different E. faecalis strains (blue) from 4 biological replicates using specific primers for each strain. Asterisks represent P values using two-sided t-test (values from left to right: 0.005, 0.027, 0.021, 0.003 and 0.001). (ii),(iii), Growth curves of L. reuteri (iii) or E. faecalis (ii) as represented by OD measured at 600 nm over time with and without E. faecalis or L. reuteri spent media. Mean + s.d. b, Bar graphs representing the fold change of the metabolites consumed by L. reuteri or E. faecalis cultured on basal defined medium as analysed by LC–MS. Fold changes of the consumed metabolites compared to the respective blank media are presented. c(i), Bar graphs displaying the fold change of the consumed and/or produced metabolites by each bacterial species. The analysis was carried out on samples cultured on spent medium obtained from the two strains on which they were grown reciprocally. All LC–MS measurements (in b and c) were performed on biological triplicates; actual values (dots), mean ± s.d. are presented. (ii), Boxplots representing supplementation assays with commercial acrylamide (n = 8) or sorbitol (n = 10) added to basal defined medium as the sole carbon source before growing L. reuteri or E. faecalis, respectively, for 20 h at 37 °C. All points are displayed and the means are represented as a line. Actual OD600 values are displayed; P values obtained with two-sided t-test. Boxes represent the interquartile range (IQR) central half of the data, the whiskers indicate the range of the data, minimum to maximum values, and individual dots represent all the measurements. d, Co-occurence of 1,3-PD gene, E. faecalis and L. reuteri in vivo. (i), Spearman correlations and (ii) co-occurrence scatterplot between the L. reuteri, E. faecalis and 1,3-PD gene abundances as determined by quantitative PCR using specific primers on 34 individual rumen samples. The x and y axes in ii represent the 16S rRNA gene copy number of E. faecalis and L. reuteri, respectively, and the circle sizes represent the 1,3-PD gene copy number.
