In macrophages, natural resistance-associated macrophage protein 1 (Nramp1) is a transport system that sequesters divalent metal cations from the pathogen, slowing growth and preventing synthesis of enzymes (superoxide dismutases and catalases) for protection against the reactive oxygen species generated in response to infection in the bacterial cell, thus rendering the pathogen more susceptible to killing by oxidative stress (Govoni and Gros, 1998; Nelson, 1999). The gene discussed is SLC11A1; the disease is infection.