realized in protective resistance smooth Brucella strain Brucella resistance to nitrosative stress The protective disposition of Brucella while exposed to high level of nitric oxide (NO) rich enviroment, or the highly reactive oxidant peroxynitrite, which is produced following interaction of NO with superoxide anions. This disposition is in virtue of Brucella's intrcellular survival. YL, YH smooth Brucella resistance to nitrosative stress inside BCV