This US-Bulgaria project between Dr. Irwin Fridovich and Dr. Stephan Liochev is on "Oxidation Effects of the Superoxide Radical in Escherichia Coli." The researchers propose a novel explanation for the toxic effects of the superoxide radical, to account for many observations already in the literature which lend themselves to experimental probing. Current orthodoxy views superoxide as a precursor of hydrogen peroxide and as a reductant for ferric ion. The researchers, in contrast, view O2, O2 and H2O2 as direct oxidants and consider Fe(II), in its various ligated forms, to be an important target for these oxidants. They have found that a number of ?4Fe-4S!-containing dehydrases are rapidly oxidatively inactivated by O2. The results should shed light on the mechanisms of oxygen toxicity and of the oxygen-dependent toxicities of viologens, quinones, aryl nitro compounds and of other redox-active compounds. This project in biochemistry science fulfills the program objective of advancing scientific knowledge by enabling leading experts in Bulgaria and the United States to combine complementary talents and pool resources in areas of strong mutual interest and competence.
