Induction of superoxide dismutases in Escherichia coli B by metal chelators

Journal Article · Mon Apr 01 04:00:00 EST 1985 · J. Bacteriol.; (United States)

OSTI ID:5553854

Pugh, S Y.R.; Fridovich, I

The effects of metal salts, chelating agents, and paraquat on the superoxide dismutases (SODs) of Escherichia coli B were explored. Mn(II) increased manganese-containing SOD (MnSOD), whereas Fe(II) increased iron-containing SOD (FeSOD). Chelating agents induced MnSOD but decreased FeSOD and markedly increased the degree of induction seen with Mn(II). Paraquat also exerted a synergistic effect with Mn(II). High levels of MnSOD were achieved in the combined presence of Mn(II), chelating agent, and paraquat. All of these effects were dependent on the presence of oxygen. MnSOD, not ordinarily present in anaerobically grown E. coli cells, was present when the cells were grown anaerobically in the presence of chelating agents. These results are accommodated by a scheme which incorporates autogenous repression by the apoSODs and competition between Fe(II) and Mn(II) for the metal-binding sites of the apoSODs. It is further supposed that oxygenation and intracellular O/sub 2//sup -/ production favor MnSOD production because O/sub 2//sup -/ oxidizes Mn(II) to Mn(III), which competes favorably with Fe(II) for the apoSODs.

• Research Organization: Duke Univ. Medical Center, Durham, NC
• OSTI ID: 5553854
• Journal Information: J. Bacteriol.; (United States), Journal Name: J. Bacteriol.; (United States) Vol. 162:1; ISSN JOBAA
• Country of Publication: United States
• Language: English

Related Subjects

560302* -- Chemicals Metabolism & Toxicology-- Microorganisms-- (-1987)
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
BACTERIA
BIOLOGICAL EFFECTS
CHELATING AGENTS
CHEMICAL BONDS
ELEMENTS
ENZYME ACTIVITY
ENZYMES
ESCHERICHIA COLI
GROWTH
HERBICIDES
IRON
MANGANESE
METALS
MICROORGANISMS
NONMETALS
OXIDOREDUCTASES
OXYGEN
PESTICIDES
SUPEROXIDE DISMUTASE
SYNERGISM
TRANSITION ELEMENTS