Fig. 6. A generalised mechanism for T3SS regulation by pentose sugar metabolism.

a Schematic illustrating where the ʟ-arabinose, D-xylose and D-ribose metabolic pathways converge with glycolysis (left-hand side) via the Pentose Phosphate Pathway (PPP). The genes involved in each conversion are illustrated. Single steps are depicted as a solid arrow. Multiple steps are abbreviated to dotted arrows. b Transcriptional reporter assay of EHEC transformed with pMK1lux-PLEE1 cultured in MEM-HEPES alone or supplemented with 1 mg/ml of D-ribose (pink) or D-xylose (orange). Data are depicted as luminescence units (LUX) divided by the optical density (OD₆₀₀) of the culture at each timepoint. c pMK1lux-PLEE1 reporter assay of WT EHEC and the ∆rbs mutant cultured in MEM-HEPES alone (grey) or supplemented with D-ribose (pink). d pMK1lux-PLEE1 reporter assay of WT EHEC cultured in MEM-HEPES alone or supplemented with 1 mg/ml ʟ-arabinose (green), 0.2% pyruvate (magenta) or a mixture of both (dashed). For (c, d), statistical significance was determined using a two-tailed student’s t-test (significant P = 0.0093, 0.0031, 0.0035 and 0.0087 where indicated from left to right on c, d). Error bars represent the standard error of the mean (n = 3 biological replicates for (c); n = 2 biological replicates for d). ** and ns indicate P < 0.01 or not significant respectively for all graphs. Source data are provided in the Source Data file.