Mid-exponential cultures of two traditional biotechnological yeast species, winery Saccharomyces cerevisiae and the less ethanol tolerant bottom-fermenting brewery Saccharomyces pastorianus, were exposed to different concentrations of added ethanol (3, 5 and 8%) The degree of ethanol-induced cell stress was assessed by measuring the cellular activity of superoxide dismutase (SOD), level of lipid peroxidation products, changes in cell lipid content and fatty acid profile. The resveratrol as an antioxidant was found to decrease the ethanol-induced rise of SOD activity and suppress the ethanol-induced decrease in cell lipids. A lower resveratrol concentration (0.5 mg/l) even reduced the extent of lipid peroxidation in cells. Resveratrol also alleviated ethanol-induced changes in cell lipid composition in both species by strongly enhancing the proportion of saturated fatty acids and contributing thereby to membrane stabilization. Lower resveratrol concentrations could thus diminish the negative effects of ethanol stress on yeast cells and improve their physiological state. These effects may be utilized to enhance yeast vitality in high-ethanol-producing fermentations or to increase the number of yeast generations in brewery.

• Keywords
• Ethanol stress, Lipid peroxidation, Resveratrol, Yeast,
• MeSH
• Antioxidants metabolism   MeSH
• Ethanol pharmacology   MeSH
• Stress, Physiological drug effects   MeSH
• Lipids physiology   MeSH
• Fatty Acids metabolism   MeSH
• Lipid Metabolism drug effects   MeSH
• Lipid Peroxidation drug effects   MeSH
• Resveratrol MeSH
• Saccharomyces cerevisiae drug effects   MeSH
• Stilbenes pharmacology   MeSH
• Superoxide Dismutase metabolism   MeSH
• Wine microbiology   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Antioxidants MeSH
• Ethanol MeSH
• Lipids MeSH
• Fatty Acids MeSH
• Resveratrol MeSH
• Stilbenes MeSH
• Superoxide Dismutase MeSH

Exposition of Cupriavidus necator to ethanol or hydrogen peroxide at the beginning of the stationary phase increases poly(3-hydroxybutyrate) (PHB) yields about 30%. Hydrogen peroxide enhances activity of pentose phosphate pathway that probably consequently increases intracellular ratio NADPH/NADP(+). This effect leads to stimulation of the flux of acetyl-CoA into PHB biosynthetic pathway and to an increase of enzymatic activities of β-ketothiolase and acetoacetyl-CoA reductase while activity of PHB synthase remains uninfluenced. During ethanol metabolisation, in which alcohol dehydrogenase is involved, acetyl-CoA and reduced coenzymes NAD(P)H are formed. These metabolites could again slightly inhibit TCA cycle while flux of acetyl-CoA into PHB biosynthetic pathway is likely to be supported. As a consequence of TCA cycle inhibition also less free CoA is formed. Similarly with hydrogen peroxide, activities of β-ketothiolase and acetoacetyl-CoA reductase are increased which results in over-production of PHB. Molecular weight of PHB produced under stress conditions was significantly higher as compared to control cultivation. Particular molecular weight values were dependent on stress factor concentrations. This could indicate some interconnection among activities of β-ketothiolase, acetoacetyl-CoA reductase and PHB molecular weight control in vivo.

• Publication type
• Journal Article MeSH

Nitric oxide (NO) stimulated the activity of plasma membrane H+-ATPase, 5'-nucleotidase, peroxidase, ascorbate peroxidase and glutathione reductase in ultraviolet B (UV-B) irradiated Chlorella pyrenoidosa. It also boosted the activity of nitrogen-metabolism enzymes such as nitrate reductase, nitrite reductase, glutamine synthetase, which were inhibited by UV-B irradiation. The chlorophyll fluorescence ratio (Fv/Fm) of the UV-B irradiated algae and decreased continuously after the cells were transferred to UV-B irradiation. A continuing decrease of the Fv/Fm was observed even after the cells were transferred to photosynthetically active radiation (PAR). After adaptation for 8 h under PAR (after treatment with nitric oxide), Fv/Fm recovered to 55 % of normal levels--without NO the value approached zero. Exogenous NO stopped the decay of chlorophyll and thylakoid membrane in cells exposed to UV-B irradiation. NO plays probably a key role in damage induced by UV-B irradiation in green algae.

• MeSH
• Algal Proteins metabolism   MeSH
• Cell Membrane enzymology   MeSH
• Chlorella physiology   radiation effects   MeSH
• Enzymes metabolism   MeSH
• Nitric Oxide physiology   MeSH
• Second Messenger Systems * MeSH
• Ultraviolet Rays * MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Algal Proteins MeSH
• Enzymes MeSH
• Nitric Oxide MeSH

A chromate-tolerant mutant chr1-663T bearing a stable one-gene mutation and its parental strain 6chr(+) were used to investigate the background of Cr(VI) tolerance in the fission yeast Schizosaccharomyces pombe. The mutant chr1-663T displayed a significantly decreased specific glutathione reductase (GR) activity coded by the pgr1 (+) gene compared with its parental strain. Transformants of the mutant chr1-663T with a nonintegrative pUR18N vector expressing the pgr1 (+) gene exhibited the same Cr(VI) sensitivity and specific GR activity as their parental strain, demonstrating the importance of the GR-NADPH system in Cr(VI) tolerance. Transformants, nevertheless, exhibited an increased intracellular peroxide concentration, a decreased Cr(VI)-reducing and HO*-producing ability, which suggested an unbalanced oxidoreduction state of cells and partial complementation of the GR function. No mutation was found in the sequences of the pgr1 (+) and the pap1 (+) (transcriptional regulatory gene of GR) genes of the Cr(VI)-tolerant mutant by sequence analysis.

• MeSH
• Chromates metabolism   pharmacology   MeSH
• Down-Regulation * MeSH
• Drug Resistance, Fungal MeSH
• Glutathione Reductase genetics   metabolism   MeSH
• Mutation * MeSH
• Oxidation-Reduction MeSH
• Pancreatitis-Associated Proteins MeSH
• Schizosaccharomyces pombe Proteins genetics   metabolism   MeSH
• Schizosaccharomyces drug effects   enzymology   genetics   metabolism   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Chromates MeSH
• Glutathione Reductase MeSH
• Pancreatitis-Associated Proteins MeSH
• REG3A protein, human MeSH Browser
• Schizosaccharomyces pombe Proteins MeSH

Hydrogen peroxide production in yeast cells undergoing programmed cell death in response to acetic acid occurred in the majority of live cells 15 min after death induction and was no longer detectable after 60 min. Superoxide anion production was found later, 60 and 90 min after death induction when cells viability was 60 and 30%, respectively. In cells protected from death due to acid stress adaptation neither hydrogen peroxide nor superoxide anion could be observed after acetic acid treatment. The early production of hydrogen peroxide in cells in which survival was 100% could play a major role in acetic acid-induced programmed cell death signaling. Superoxide anion is assumed to be generated in cells already en route to acetic acid-induced programmed cell death.

• MeSH
• Apoptosis physiology   MeSH
• Catalase metabolism   MeSH
• Acetic Acid pharmacology   MeSH
• Acids pharmacology   MeSH
• Hydrogen Peroxide metabolism   MeSH
• Saccharomyces cerevisiae enzymology   physiology   MeSH
• Superoxide Dismutase metabolism   MeSH
• Superoxides metabolism   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Catalase MeSH
• Acetic Acid MeSH
• Acids MeSH
• Hydrogen Peroxide MeSH
• Superoxide Dismutase MeSH
• Superoxides 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

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

The activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSP) as well as of succinate dehydrogenase (SDG), NADH dehydrogenase (NDG) and fumarate hydratase (FHT) were examined in relation to mitochondrial ultrastructure changes in Aspergillus niger exposed to N,N-bis(3-aminopropyl)dodecylamine (Apd) that was shown to exhibit fungicidal activity. There was a progressive increase in SOD, CAT and GSP activities 1 and 4 h after 0.05 and 0.1 % Apd application. However, this was followed by a pronounced activity decrease when 0.05 % Apd treatment was prolonged by 1 d. The destructive effect on fungal morphology was observed when this fungicidal agent was applied at the concentration of 0.1 % for 1 d. In the treated hyphae mitochondria degenerated after all organelles. The morphological malformations of mitochondria had an impact on their metabolic state; however, the activities of SDG, NDG and FHT were affected to a different extent. In A. niger the fungicidal effect of Apd could be mediated by oxidative stress impairing the vital mitochondria-related cellular functions.

• MeSH
• Amines pharmacology   MeSH
• Antifungal Agents pharmacology   MeSH
• Aspergillus niger drug effects   metabolism   ultrastructure   MeSH
• Time Factors MeSH
• Fumarate Hydratase metabolism   MeSH
• Glutathione Peroxidase metabolism   MeSH
• Hyphae drug effects   ultrastructure   MeSH
• Enzyme Inhibitors pharmacology   MeSH
• Catalase metabolism   MeSH
• Mitochondria drug effects   metabolism   ultrastructure   MeSH
• NADH Dehydrogenase metabolism   MeSH
• Succinate Dehydrogenase metabolism   MeSH
• Superoxide Dismutase metabolism   MeSH
• Microscopy, Electron, Transmission MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Amines MeSH
• Antifungal Agents MeSH
• Fumarate Hydratase MeSH
• Glutathione Peroxidase MeSH
• Enzyme Inhibitors MeSH
• Catalase MeSH
• N,N-bis(3-aminopropyl)dodecylamine MeSH Browser
• NADH Dehydrogenase MeSH
• Succinate Dehydrogenase MeSH
• Superoxide Dismutase MeSH

The effect of selenium supplementation on the rumen protozoan population of sheep was demonstrated. Both the total and generic counts of rumen ciliates in sheep fed a diet with basal Se content (70 microg/kg dry matter) were compared to those of animals given feed supplemented with inorganic (disodium selenite) or organic Se (selenized yeast) (310 microg/kg dry matter). The genera of Entodinium, Isotricha, Dasytricha, Ophryoscolex, Diploplastron and Polyplastron occurred in all sheep except for the control, in which Ophryoscolex was not observed. The population of Ophryoscolex caudatus f. tricoronatus was significantly higher in sheep supplemented with organic Se than in animals given inorganic Se (by 160 %). Supplementation of feed with selenized yeast induced significant growth in the Diploplastron population (by 63 %) while no change occurred in sheep given selenite. The populations of Dasytricha ruminantium and Polyplastron multivesiculatum were higher than control in both Se-supplemented groups. The ciliate population of Entodinium spp. was not influenced by Se supplements. Our results suggest a protective effect of Se feed supplementation on the development of some rumen ciliate species in young ruminants.

• MeSH
• Inorganic Chemicals MeSH
• Rumen drug effects   parasitology   MeSH
• Ciliophora drug effects   growth & development   MeSH
• Organic Chemicals administration & dosage   pharmacology   MeSH
• Sheep, Domestic parasitology   MeSH
• Dietary Supplements * MeSH
• Selenium pharmacology   MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Inorganic Chemicals MeSH
• Organic Chemicals MeSH
• Selenium MeSH

Physiological and morphological changes in carbon-limited autolyzing cultures of Aspergillus nidulans were described. The carbon starvation arrested conidiation while the formation of filamentous and "yeast-like" hyphal fragments with profoundly altered metabolism enabled the fungus to survive the nutritional stress. The morphological and physiological stress responses, which maintained the cellular integrity of surviving hyphal fragments at the expense of autolyzing cells, were highly concerted and regulated. Moreover, sublethal concentrations of the protein synthesis inhibitor cycloheximide or the mitochondrial uncoupler 2,4-dinitrophenol completely blocked the autolysis. In accordance with the propositions of the free-radical theory of ageing reactive oxygen species accumulated in the surviving fragments with a concomitant increase in the specific superoxide dismutase activity and a continuous decrease in cell viability. Glutathione was degraded extensively in carbon-starving cells due to the action of gamma-glutamyltranspeptidase, which resulted in a glutathione-glutathione disulfide redox imbalance during autolysis.

• MeSH
• Aspergillus nidulans growth & development   metabolism   MeSH
• Autolysis * MeSH
• Gluconeogenesis MeSH
• Glutathione metabolism   MeSH
• Morphogenesis MeSH
• Carbon metabolism   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Glutathione MeSH
• Carbon MeSH