RESEARCH ARTICLE Superoxide Dismutases, SOD1 and SOD2, Play a Distinct Role in the Fat Body during

One way that aerobic biological systems counteract the generation of reactive oxygen spe-cies (ROS) is with superoxide dismutase proteins SOD1 and SOD2 that metabolize super-oxide radicals to molecular oxygen and hydrogen peroxide or scavenge oxygen radicals produced by the extensive oxidation-reduction and electron-transport reactions that occur in mitochondria. We characterized SOD1 and SOD2 of Bombyx mori isolated from the fat body of larvae. Immunological analysis demonstrated the presence of BmSOD1 and BmSOD2 in the silk gland, midgut, fat body, Malpighian tubules, testis and ovary from larvae to adults. We found that BmSOD2 had a unique expression pattern in the fat body through the fifth instar larval developmental stage. The anti-oxidative functions of BmSOD1 and BmSOD2 were assessed by exposing larvae to insecticide rotenone or vasodilator isosor-bide dinitrate, which is an ROS generator in BmN4 cells; however, exposure to these com-pounds had no effect on the expression levels of either BmSOD protein. Next, we investigated the physiological role of BmSOD1 and BmSOD2 under environmental oxida-tive stress, applied through whole-body UV irradiation and assayed using quantitative RT