(A) BRV conversion to BVU by representative human gut isolates. (B) Log2 fold change of BRV and BVU concentrations of B. thetaiotaomicron transposon insertion mutants (blue, n = 1290) compared to media controls (grey, n = 83) after 24 h of incubation. Each point represents one strain, sorted along the x-axis in the same order in top (BRV) and bottom (BVU) panels. Mean fold changes and 95% prediction intervals for controls and strains are indicated by solid lines and shaded areas, respectively. (C) BRV conversion by B. thetaiotaomicron wildtype (n=4), bt4554 mutant (n=4), and complemented strains expressing bt4554 at different levels (n=8). In (A) and (C), lines and shaded areas depict the mean and STD of independent cultures (n=4–8).