High levels of catalase in sod mutants of Saccharomyces cerevisiae in high aeration conditions

Abstract

Saccharomyces cerevisiae mutants deficient in superoxide dismutase genes (sod1Δ, sod2Δ and sod1Δsod2Δ mutants) in a stationary phase of growth under high aeration conditions were subjected to H2O2 stress. All the mutants were sensitive after H2O2 treatment. Glutathione peroxidase levels were significantly lower in sod1Δ and sod2Δ single mutants than in the wild-type without treatment. After exposure to H2O2 concentrations, glutathione peroxidase levels were increased in sod1Δsod2Δ double mutants and the sod2Δ single mutant, while sod1Δ maintained lower gluthatione peroxidase activities. The sod2Δ mutant demonstrated a similar catalase activity to that of the wild-type without treatment, whilst decreased catalase activity was observed in conditions of low aeration. Untreated sod1Δsod2Δ double mutant cells presented a lower catalase activity. Catalase levels were higher under high aeration conditions than under microaerophilic conditions, including in sod1Δsod2Δ cells that contain less H2O2, since SOD catalyzes the cleavage of superoxide producing H2O2 and oxygen. We suggest that catalase is not essential for sod mutants under normal conditions, but plays an important role in the acquisition of tolerance to oxidative stress induced by high aeration.

Fructose protects baker's yeast against peroxide stress: potential role of catalase and superoxide dismutase

“…However, many studies reported a lack of correlation between the expression of certain genes at different levels of cellular organization (Gygi et al ., ; Cyrne et al ., ; Holcik & Sonenberg, ; Semchyshyn, ). The weak elevation of catalase and SOD activities in yeast treated with sublethal concentrations of H 2 O 2 reported earlier (Izawa et al ., ; Martins et al ., ; Bayliak et al ., , ) as well as found in this study, does not correspond to high level of Yap1p‐dependent synthesis of the respective enzyme molecules under the same experimental conditions (Godon et al ., ; Lee et al ., ). It is well known that exposure of microrganisms to low sublethal concentrations of hydrogen peroxide leads to the acquisition of cellular resistance to a subsequent lethal stress (Collinson & Dawes, ; Semchyshyn et al ., ).…”

Hormetic Effect of H2O2 in Saccharomyces cerevisiae

“…52,53 An increasing number of studies have reported a lack of correlation between gene expression at different levels of cellular organization. 50,51,[54][55][56] The weak elevation in antioxidant enzyme activities in yeast treated with sublethal concentrations of H 2 O 2 10,33,48,57 did not correspond to reported earlier high level of synthesis of the respective enzyme molecules. 26,58 Exposure of microorganisms to low hormetic concentrations of H 2 O 2 leads to the acquisition of cellular resistance to a subsequent lethal stress.…”

Study of energetic-particle-irradiation induced biological effect on Rhizopus oryzae through synchrotron-FTIR micro-spectroscopy

“…For example, superoxide dismutase (SOD) catalyzes dismutation of the superoxide anion into hydrogen peroxide and molecular oxygen, catalase (CAT) reacts with hydrogen peroxide to form water and molecular oxygen. In the mean time, a variety of non-enzymatic antioxidants, such as ascorbic acid, glutathione and thioredoxin, can also play an important role in the cellular response to irradiation by the detoxification of oxygen radicals [7][8][9].…”