Two classes of newly synthesized amphiphilic compounds, phenolic antioxidants ("phenolics") and N-oxides exert in vivo antioxidant effects on live S. cerevisiae cells. Both groups have low toxicity, phenolics being more toxic than N-oxides and compounds with a longer alkyl chain having higher toxicity than those with a shorter alkyl chain. Phenolic antioxidants protect yeast cells exposed to the superoxide producer paraquat and peroxyl generator tert-butylhydroperoxide better than N-oxides at 3-fold higher concentration. Both types of antioxidants enhance the survival of pro-oxidant-exposed cells of S. cerevisiae mutants deficient in cytosolic and/or mitochondrial superoxide dismutase and could be good compounds which mimic the role of superoxide dismutases. The results of measurement of antioxidant activity in an in vitro chemiluminescence test differ from the results obtained in vivo with S. cerevisiae superoxide dismutase mutants. In contrast to their action on live cells, phenolics are less effective than N-oxides in preventing lipid peroxidation of an emulsion of lipids isolated from S. cerevisiae membranes.

• MeSH
• Amines chemistry   pharmacology   toxicity   MeSH
• Antifungal Agents toxicity   MeSH
• Antioxidants chemistry   pharmacology   toxicity   MeSH
• Gene Deletion MeSH
• Phenols chemistry   pharmacology   toxicity   MeSH
• Quaternary Ammonium Compounds chemistry   pharmacology   toxicity   MeSH
• Membrane Lipids metabolism   MeSH
• Microbial Viability MeSH
• Paraquat toxicity   MeSH
• Lipid Peroxidation MeSH
• Saccharomyces cerevisiae drug effects   MeSH
• Superoxide Dismutase genetics   MeSH
• tert-Butylhydroperoxide toxicity   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Amines MeSH
• Antifungal Agents MeSH
• Antioxidants MeSH
• Phenols MeSH
• Quaternary Ammonium Compounds MeSH
• Membrane Lipids MeSH
• Paraquat MeSH
• Superoxide Dismutase MeSH
• tert-Butylhydroperoxide MeSH

Superoxide dismutases, both cytosolic Cu, Zn-SOD encoded by SOD1 and mitochondrial Mn-SOD encoded by SOD2, serve Saccharomyces cerevisiae cells for defense against the superoxide radical but the phenotypes of sod1A and sod2delta mutant strains are different. Compared with the parent strain and the sod1delta mutant, the sod2delta mutant shows a much more severe growth defect at elevated salt concentrations, which is partially rescued by 2 mmol/L glutathione. The growth of all three strains is reduced at 37 degrees C, the sod2delta showing the highest sensitivity, especially when cultured in air. Addition of 1 mmol/L glutathione to the medium restores aerobic growth of the sod1delta mutant but has only a minor effect on the growth of the sod2delta strain at 37 degrees C. The sod2delta strain is also sensitive to AsIIl and AsV and its sensitivity is much more pronounced under aerobic conditions. These results suggest that, unlike the Sodlp protein, whose major role is oxidative stress defense, Sod2p also plays a role in protecting S. cerevisiae cells against other stresses--high osmolarity, heat and metalloid stress.

• MeSH
• Aerobiosis MeSH
• Arsenic MeSH
• Sodium Chloride MeSH
• Glutathione pharmacology   MeSH
• Culture Media MeSH
• Mitochondria enzymology   MeSH
• Osmolar Concentration MeSH
• Saccharomyces cerevisiae Proteins physiology   MeSH
• Saccharomyces cerevisiae drug effects   physiology   MeSH
• Superoxide Dismutase-1 MeSH
• Superoxide Dismutase physiology   MeSH
• Hot Temperature MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Arsenic MeSH
• Sodium Chloride MeSH
• Glutathione MeSH
• Culture Media MeSH
• Saccharomyces cerevisiae Proteins MeSH
• Superoxide Dismutase-1 MeSH
• Superoxide Dismutase MeSH
• superoxide dismutase 2 MeSH Browser

Damage caused to Saccharomyces cerevisiae SY4 plasma membrane H(+)-ATPase by Fe- and Cu-Fenton reagents was determined in secretory vesicles containing enzyme in which Cys residues were replaced singly or in pairs by Ala. Cys-221 situated in a beta-sheet domain between M2 and M3 segments, phosphorylation domain-located Cys-409 and Cys-532 situated at the ATP-binding site play a role in the inactivation. In the presence of all three residues the enzyme exhibited a certain basic inactivation, which did not change when Cys-532 was replaced with Ala. In mutants having intact Cys-532 but lacking one or both other cysteines, replacement of Cys-221 with Ala led to lower inactivation, suggesting that Cys-221 may serve as a target for metal-catalyzed oxidation and intact Cys-532 promotes this target role of Cys-221. In contrast, the absence of Cys-409 caused higher inactivation by Fe-Fenton. Cys-532 thus seems to serve as a target for Fe-Fenton, intact Cys-409 causing a conformational change that makes Cys-532 less accessible to oxidation. The mutant lacking both Cys-221 and Cys-409 is more sensitive to Fe-Fenton than to Cu-Fenton and the absence of both Cys residues thus seems to expose presumable extra Fe-binding sites. These data and those on protection by ATP, ADP, 1,4-dithiothreitol and deferrioxamine B point to complex interactions between individual parts of the enzyme molecule that determine its sensitivity towards Fenton reagents. ATPase fragmentation caused by the two reagents differed in that the Fe-Fenton reagent produced in Western blot "smears" whereas the Cu-Fenton reagent produced defined fragments.

• MeSH
• Cell Membrane drug effects   enzymology   MeSH
• Cysteine metabolism   MeSH
• Copper MeSH
• Mutation MeSH
• Oxidative Stress drug effects   MeSH
• Hydrogen Peroxide pharmacology   MeSH
• Proton-Translocating ATPases chemistry   genetics   metabolism   MeSH
• Saccharomyces cerevisiae chemistry   drug effects   enzymology   MeSH
• Amino Acid Substitution MeSH
• Free Radicals MeSH
• Structure-Activity Relationship MeSH
• Iron pharmacology   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Cysteine MeSH
• Fenton's reagent MeSH Browser
• Copper MeSH
• Hydrogen Peroxide MeSH
• Proton-Translocating ATPases MeSH
• Free Radicals MeSH
• Iron MeSH

S. cerevisiae strain delta sodl lacking Cu,Zn-superoxide dismutase and delta sodl delta sod2 mutant lacking both Cu,Zn-SOD and Mn-superoxide dismutase displayed strongly reduced aerobic growth on glucose, glycerol and lactate; delta sod2 deletion had no effect on aerobic growth on glucose and largely precluded growth on glycerol and lactate. The oxygen-induced growth defects and their alleviation by antioxidants depended on growth conditions, in particular on oxygen supply to cells. Under strong aeration, vitamins A and E had a low effect, 100 mumol/L quercetin alleviated the growth defects of all three mutants while beta-carotene had no growth-restoring effect. The superoxide producer paraquat inhibited the aerobic growth of all three mutants in a concentration-dependent manner. Low concentrations of antioxidants had no effect on paraquat toxicity while higher concentrations supported the toxic effect of the agent.

• MeSH
• Antioxidants pharmacology   MeSH
• Bacteriological Techniques MeSH
• Phenotype MeSH
• Oxygen pharmacology   MeSH
• Oxidative Stress drug effects   MeSH
• Partial Pressure MeSH
• Saccharomyces cerevisiae drug effects   genetics   metabolism   MeSH
• Superoxide Dismutase-1 MeSH
• Superoxide Dismutase genetics   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Antioxidants MeSH
• Oxygen MeSH
• Superoxide Dismutase-1 MeSH
• Superoxide Dismutase MeSH
• superoxide dismutase 2 MeSH Browser

Effects of four lipid peroxidation-inducing pro-oxidants--amphiphilic tert-butyl hydroperoxide (TBHP), hydrophobic 1,1'-azobis(4-cyclohexanecarbonitrile) (ACHN), hydrophilic FeII and 2,2'-azobis(2-amidinopropane)dihydrochloride (AAPH)--on cell growth and on generation of peroxidation products in isolated plasma membrane lipids were determined in four yeast species (S. cerevisiae, S. pombe, R. glutinis and C. albicans) differing in their plasma membrane lipid composition. TBHP and ACHN inhibited cell growth most strongly, FeII and AAPH exerted inhibitory action for about 2 h, with subsequent cell growth resumption. S. cerevisiae strain SP4 was doped during growth with unsaturated linoleic (18:2) and linolenic (18:3) acids to change its resistance to lipid peroxidation. Its plasma membranes then contained some 30% of these acids as compared with some 1.3% of 18:2 acid found in undoped S. cerevisiae, while the content of (16:1) and (18:1) acids was lower than in undoped S. cerevisiae. The presence of linoleic and linolenic acids in S. cerevisiae cells lowered cell survival and increased the sensitivity to pro-oxidants. Peroxidation-generated conjugated dienes (CD) were measured in pure TBHP- and ACHN-exposed fatty acids used as standards. The CD level depended on the extent of unsaturation and the pro-oxidant used. The TBHP-induced CD production in a mixture of oleic acid and its ester was somewhat lower than in free acid and ester alone. In lipids isolated from the yeast plasma membranes, the CD production was time-dependent and decreased after a 5-15-min pro-oxidant exposure. ACHN was less active than TBHP. The most oxidizable were lipids from S. cerevisiae plasma membranes doped with linoleic and linolenic acids and from C. albicans with indigenous linolenic acid.

• MeSH
• Cell Membrane drug effects   metabolism   MeSH
• Candida albicans drug effects   metabolism   MeSH
• Hydrophobic and Hydrophilic Interactions MeSH
• Lipid Metabolism MeSH
• Lipid Peroxidation drug effects   MeSH
• Reactive Oxygen Species pharmacology   MeSH
• Rhodotorula drug effects   metabolism   MeSH
• Saccharomyces cerevisiae drug effects   metabolism   MeSH
• Schizosaccharomyces drug effects   metabolism   MeSH
• Free Radicals metabolism   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Comparative Study MeSH
• Names of Substances
• Reactive Oxygen Species MeSH
• Free Radicals MeSH