Superoxide Dismutase and Oxygen Toxicity in a Eukaryote

Abstract

Saccharomyces cerevisiae var. ellipsoideus contained 6.5 times more superoxide dismutase and 2.3 times more catalase when grown under 100% 02 than when grown anaerobically. Growth under oxygen caused equal increases in both the cyanide-sensitive and the cyanide-insensitive superoxide dismutases of this organism. Experience with other eukaryotes has shown that cyanide sensitivity is a property of the cupro-zinc superoxide dismutase of the cytosol, whereas cyanide insensitivity is a property of the corresponding mangani-enzyme found in mitochondria. Cu2+, which has been shown to increase the radioresistance of yeast, also caused an increase of both of the superoxide dismutases of S. cerevisiae. Yeast which had been grown under 1 atm of 02 were more resistant toward the lethal effects of 20 atm of 02 than were yeast which had been grown in the absence of 0,. Escherichia coli K-12 his-responded to growth under 1 atm of 02 by increasing its content of catalase and of peroxidase, but not of superoxide dismutase. This contrasts with E. coli B, which was previously shown to respond to 02 by a striking increase in superoxide dismutase. E. coli K-12 his-did not gain resistance toward 20 atm of 02 because of having been grown under 1 atm of 02. Once again, this contrasts with the behavior of E. coli B. These data indicate that, in both prokaryotes and in eukaryotes, superoxide dismutase is an important component of the defenses against oxygen toxicity.

Biosynthesis of superoxide dismutase in eight prokaryotes: Effects of oxygen, paraquat and an iron chelator

“…Elevated pO 2 induces MnSOD in E. coli [2], S. faecalis [17], Streptococcus sanguis [18], Saccharomyces cerevisiae [19] and Bacteroides fragilis [20] as well as FeSOD in Bdellovibrio stolpii [21]. Therefore, it was not surprising to find that the activities of SOD in the test organisms increased as a function of the oxygen concentration supplied to the media (Table 1).…”

Hydrogen peroxide as an electron acceptor for mitochondrial respiration in the yeast Hansenula polymorpha

“…Paraquat, a superoxide anion-generating drug (Carr et al, 1986), has been used successfully to elevate the level of SOD in numerous E. coli strains (Hassan and Fridovich, 1979;Carr et al, 1986). However, in at least one strain, SOD activity was not affected at all (Gregory et al, 1974). Treatment of S .…”

“…Treatment of S . cerevisiue with paraquat resulted in an increase in SOD activity (Gregory et al, 1974;Lee and Hassan, 1987). A further factor which may affect the level of SOD in various microorganisms is the oxygen tension.…”

Synthesis of superoxide dismutase, catalase and other enzymes and oxygen and superoxide toxicity during changes in oxygen concentration in cultures of brewing yeast

“…(1) 2 0 , -+ 2H' --* O,+ HzOz It is known to be active in protecting living cells, including yeast, from such toxic effects (Gregory et a[., 1974). It is still not certain whether superoxide itself is the actual toxic agent.…”