Similarly, infection of murine macrophages (lipopolysaccharide (LPS) and IFN-γ-activated to produce nitric oxide29) demonstrated that mutation of cydAB, hmp, norVW and ytfE led to a significant reduction in bacterial loads at 2 h post-infection, whereas loss of nrfA had no discernible effect (Fig. 4A). The gene discussed is IFNG; the disease is infection.