Papers by Tomasz Bilinski
Journal of General Microbiology, 1974
MGG - Molecular and General Genetics
Kurozumi et al. have shown that different yeast species could be separated on Dowex 1 columns. Th... more Kurozumi et al. have shown that different yeast species could be separated on Dowex 1 columns. The authors applied a similar method to separate different strains of Saccharomyces cerevisiae.
MGG - Molecular and General Genetics
Catalase A and T activities were investigated in two standard strains and three catalase regulato... more Catalase A and T activities were investigated in two standard strains and three catalase regulatory cgr mutants of yeast in respiratory competent and incompetent states, which were under various degrees of glucose repression. The formation of catalase A was very sensitive to glucose repression and was characterized by a long delay in derepression. Deprivation of the energy source in respiratory incompetent cells prevented the derepression of catalase A. The lack of catalase A in respiratory imcompetent cells can be overcome by growing the cells in raffinose or by the prolongation of the fermentative phase of derepression. Catalase T is under control of different regulatory systems probably common with some other haemoproteins.
MGG - Molecular and General Genetics
A procedure was described for the isolation of mutants affected in the regulation of catalase act... more A procedure was described for the isolation of mutants affected in the regulation of catalase activity. Two such mutants, cgr 1 and cgr 2 were obtained. Both of them show catalase activity that is resistant to repression by glucose, but is sensitive to anoxia to the same extent as the wild type.
Acta microbiologica Polonica. Series A: Microbiologia generalis
Morphological changes and synthesis of DNA, RNA and protein during conjugation of Saccharomyces c... more Morphological changes and synthesis of DNA, RNA and protein during conjugation of Saccharomyces cerevisiae was studied. It was found that during conjugation distinct cell expansion and increase in the dry mass of the cell takes place. DNA synthesis is inhibited during mating while synthesis of RNA and protein is not affected. Conjugation of temperature sensitive mutant defective in elongation of DNA chain was normal both in permissive and restrictive temperature. Conjugation of mutants defective in the initiation of DNA synthesis or defective in RNA and protein synthesis was inhibited in restrictive temperature. The results obtained with temperature sensitive mutants suggest that RNA and protein synthesis is necessary for mating reaction while DNA synthesis is not required.
Acta microbiologica Polonica. Series A: Microbiologia generalis
The following stages of mating reaction were analysed in electron micrographs: initial contact of... more The following stages of mating reaction were analysed in electron micrographs: initial contact of the conjugating cells, formation of a tube-like structure between the mating partners, nuclear fusion and formation of first diploid bud. Nuclear fusion was observed to take place within the conjugation tube, the fusion nucleus, however, was often localised in one of the initial conjugants. The stage of fusion nucleus, preceding the first diploid bud formation, is of longest duration in the mating process. The second longest stage is the formation of a tube-like structure. The whole conjugation process lasts at 25 degrees approximately 60 min. According to the autoradiographic data, DNA synthesis begins after nucelar fusion and proceeds during formation of the first diploid bud.
Journal of general microbiology
Acta biochimica Polonica
Mutants of Saccharomyces cerevisiae devoid of Cu,Zn-superoxide dismutase are hypersensitive to a ... more Mutants of Saccharomyces cerevisiae devoid of Cu,Zn-superoxide dismutase are hypersensitive to a range of oxidants, hyperbaric oxygen and hyperosmotic media, show lysine and methionine auxotrophy when grown under the atmosphere of air and have a shortened replicative life span when compared to the wild-type strain. Ascorbate and other antioxidants can ameliorate these defects, which may be a basis of simple tests sensing the presence of antioxidants. In particular, tests of growth on solid medium (colony formation) in the absence of methionine and/or lysine, or in the presence of 0.8 M NaCl can be useful for detection and semiquantitative estimation of compounds of antioxidant properties. Hypoxic atmosphere was found to increase the sensitivity of detection of antioxidants. The test of abolishment of lysine auxotrophy showed a concentration dependence of the antioxidant effects of cysteine and N-acetylcysteine which, however, lost their protective action at high concentration, in co...
Biochemistry and molecular biology international
The content of reactive carbonyls and of glutathione-protein mixed disulfides, two indices of oxi... more The content of reactive carbonyls and of glutathione-protein mixed disulfides, two indices of oxidative stress, were compared in wild-type Saccharomyces cerevisiae and in strains deficient in superoxide dismutase and catalase, and of decreased glutathione level. Both indices were higher in stationary than in logarithmic cultures and were not increased in antioxidant-deficient strains. Oxidation of dichlorofluorescin, an estimate of peroxide production, measured in the presence of exogenous peroxidase, was higher in antioxidant-deficient strains. These results corroborate our previous results on compensatory antioxidant mechanisms in the mutant yeast strains.
Acta microbiologica Polonica
It has been found that yeast cells are sensitive to iron overload only when grown on glucose as a... more It has been found that yeast cells are sensitive to iron overload only when grown on glucose as a carbon source. Effective concentration of ferrous iron is much higher than that found in natural environments. Effects of ferrous iron are strictly oxygen dependent, what suggest that the formation of hydroxyl radicals in the Fenton reaction is a cause of the toxicity. Respiratory deficiency and pretreatment of cells with antimycin A prevent toxic effects in the late exponential phase of growth, whereas uncouplers and 2mM magnesium salts completely protect even the most vulnerable exponential cells. Generally, toxic effects correlate with the ability of cells to take up this metal. The results presented suggest that during ferrous iron overload iron is transported through the unspecific divalent cation uptake system which is known in fungi. The data suggest that recently described high and low affinity systems of iron uptake in yeast are the only source of iron in natural environments.
Acta biochimica Polonica
Deficiencies in superoxide dismutases (Cu,ZnSOD or Mn-SOD) strongly shorten the life span of yeas... more Deficiencies in superoxide dismutases (Cu,ZnSOD or Mn-SOD) strongly shorten the life span of yeast cells. The effects of these deficiencies are additive. In contrast, deficiencies in catalases do not influence life span. Our results confirm that free radical processes may be involved in aging.
Biochemistry and molecular biology international
Reactivity which organic radicals was compared in yeast (Saccharomyces cerevisiae) strains defect... more Reactivity which organic radicals was compared in yeast (Saccharomyces cerevisiae) strains defective in catalase and superoxide dismutase, and with a decreased level of glutathione. Yeast cell homogenates did not show considerable strain-related differences in the ability to scavenge nitroxide (TEMPO) stable free radicals and alkoxyl free radicals generated by decomposition of the free radical initiator AAPH. The "total antioxidant status" based on scavenging of ABTS free radicals showed a good correlation with the radiation resistance of the yeasts. These results point to the importance of other factors, apart from antioxidative enzymes and glutathione, in the determination of cellular resistance to ionizing radiation and other types of free-radical stress.
Biochemistry and molecular biology international
The effect of chosen compounds on the total glutathione (GSH) level in stationary cultures of S. ... more The effect of chosen compounds on the total glutathione (GSH) level in stationary cultures of S. cerevisiae was compared. 1-Chloro-2,4-dinitrobenzene, 1-fluoro-2,4-dinitrobenzene, maleimide, iodacetamide and allyl alcohol (1 mM), and menadione (0.5 mM) caused an almost complete GSH depletion during several minutes. Bromobenzoic acid and chloramine T (I mM), and daunomycin (60 mu M) induced a slower GSH decrease, down to 30-70% after 60 min. Paraquat (1 mM), CuSO(4) (0.5 mM) and cadmium acetate (1 mM) decreased glutathione level down to ca 70%. Diamide (0.5 mM), phenazine methosulphate, phenylhydrazine, acetylphenylhydrazine and H(2)O(2) (1 mM), and t-butyl hydroperoxide (2 mM) did not affect total GSH during 60-min exposure. There was no clear-cut dependence between the ability of various chemicals to deplete cellular GSH and their increased toxicity to a glutathione-poor mutant.
Acta biochimica Polonica
In a previous paper (Krawiec, Z., Biliński, T., Schüller, C. & Ruis, H., 2000, Acta Biochim. Polo... more In a previous paper (Krawiec, Z., Biliński, T., Schüller, C. & Ruis, H., 2000, Acta Biochim. Polon. 47, 201-207) we have shown that catalase T holoenzyme is synthesized in the absence of oxygen after treatment of anaerobic yeast cultures with 0.3 M. NaCl, or during heat shock. This finding suggests that heme moiety of the enzyme can either be formed de novo in the absence of oxygen, or derives from the preexisting heme pool present in cells used as inoculum. The strain bearing hem1 mutation, resulting in inability to form delta-aminolevulinate (ALA), the first committed precursor of heme, was used in order to form heme-depleted cells used as inocula. The cultures were supplemented with ALA at the end of anaerobic growth prior the stress treatment. The appearance of active catalase T in the stressed cells strongly suggests that heme moiety of catalase T is formed in the absence of oxygen. This finding suggests the necessity to reconsider current opinions concerning mechanisms of heme...
Acta biochimica Polonica
Reaching the limit of cell divisions, a phenomenon referred to as replicative aging, of the yeast... more Reaching the limit of cell divisions, a phenomenon referred to as replicative aging, of the yeast Saccharomyces cerevisiae involves a progressive increase in the cell volume. However, the exact relationship between the number of cell divisions accomplished (replicative age), the potential for further divisions and yeast cell volume has not been investigated thoroughly. In this study an increase of the yeast cell volume was achieved by treatment with pheromone alpha for up to 18 h. Plotting the number of cell divisions (replicative life span) of the pheromone-treated cells as a function of the cell volume attained during the treatment showed an inverse linear relationship. An analogous inverse relationship between the initial cell volume and replicative life span was found for the progeny of the pheromone-treated yeast. This phenomenon indicates that attaining an excessive volume may be a factor contributing to the limitation of cellular divisions of yeast cells.
Acta biochimica Polonica
The lifespan of budding yeast cells is divided into two stages: reproductive and post-reproductiv... more The lifespan of budding yeast cells is divided into two stages: reproductive and post-reproductive. The post-reproductive stage of the yeast's lifespan has never been characterized before. We have analyzed the influence of various mutations on the post-reproductive (PRLS) and replicative (RLS) lifespans. The results indicate that PRLS demonstrates an inverse relationship with RLS. The observed lack of differences in the total lifespan (TLS) (expressed in units of time) of strains differing up to five times in RLS (expressed in the number of daughters formed) suggests the necessity of revision of opinions concerning the use of yeast as a model organism of gerontology.
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Papers by Tomasz Bilinski