Fig. 2.

Stimulation of EsxA secretion is specific to the Fe-loaded PPIX. RN6390 was subcultured into TSB medium supplemented with the indicated additives, and grown aerobically until an OD₆₀₀ of 2 was reached. Samples were fractionated to give cells and supernatant (sn), and supernatant proteins were precipitated using TCA. For each gel, 4 µl of a cell culture adjusted to an OD₆₀₀ of 1 and 12 µl of culture supernatant were loaded. Human haemoglobin (hhg) was added at a final concentration of either 25 or 50 µg FeCl₂ ml⁻¹ at 5 µM and all other supplements at 2 µM. PPIX, protoporphyrin IX. Western blots were probed with anti-EsxA or anti-TrxA (cytoplasmic control) antisera.