Oxygen toxicity in Streptococcus mutans: manganese, iron and superoxide dismutase

Journal Article · Sun Jul 01 00:00:00 EDT 1984 · J. Bacteriol.; (United States)

OSTI ID:5972800

Martin, M E; Strachan, R C; Aranha, H; Evans, S L; Salin, M L; Welch, B; Arceneaux, J E.L.; Byers, B R

When cultured anaerobically in a chemically defined medium that was treated with Chelex-100 to lower its trace metal content, Streptococcus mutans OMZ176 had no apparent requirement for manganese or iron. Manganese or iron was necessary for aerobic cultivation in deep static cultures. During continuous aerobic cultivation in a stirred chemostat, iron did not support the growth rate achieved with manganese. Since the dissolved oxygen level in the chemostat cultures was higher than the final level in the static cultures, manganese may be required for growth at elevated levels. In medium supplemented with manganese, cells grown anaerobically contained a low level of superoxide dismutase (SOD) activity; aerobic cultivation increased SOD activity at least threefold. In iron-supplemented medium, cells grown anaerobically also had low SOD activity; aerobic incubation resulted in little increase in SOD activity. Polyacrylamide gel electrophoresis of the cell extracts revealed a major band and a minor band of SOD activity in the cells grown with manganese; however, cells grown with iron contained a single band of SOD activity with an R/sub f/ value similar to that of the major band found in cells grown with manganese. None of the SOD activity bands were abolished by the inclusion of 2 mM hydrogen peroxide in the SOD activity strain. S. mutans may not produce a separate iron-containing SOD but may insert either iron or manganese into an apo-SOD protein. Alternatively, iron may function in another activity (not SOD) that augments the defense against oxygen toxicity at low SOD levels. 28 references, 3 figures, 1 table.

• Research Organization: Univ. of Mississippi, Jackson
• OSTI ID: 5972800
• Journal Information: J. Bacteriol.; (United States), Vol. 159:2
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
IRON
BIOLOGICAL EFFECTS
MANGANESE
OXYGEN
TOXICITY
STREPTOCOCCUS
GROWTH
SUPEROXIDE DISMUTASE
ENZYME ACTIVITY
AEROBIC CONDITIONS
ANAEROBIC CONDITIONS
CHEMICAL OXYGEN DEMAND
NUTRIENTS
BACTERIA
ELEMENTS
ENZYMES
METALS
MICROORGANISMS
NONMETALS
OXIDOREDUCTASES
TRANSITION ELEMENTS
560302* - Chemicals Metabolism & Toxicology- Microorganisms- (-1987)