Showing papers on "Yeast published in 1972"
136 citations
TL;DR: A nearly complete amino acid sequence for the protein sub-unit of yeast GPDH is reported, which is a further step towards the identification of the structural elements responsible for the differences in properties between the yeast and muscle enzymes.
119 citations
TL;DR: The nucleotide sequence of a yeast formylatable methionine transfer RNA, which had previously been shown to initiate the synthesis of proteins in eukaryotic systems, has been deduced and is replaced by G-A-U-C - common to all tRNAs which are active in protein synthesis.
112 citations
TL;DR: The toxic factor secreted by killer strains of yeast and its effects on sensitive strains have been explored in detail and it is shown that this factor has an important role in cell reprograming.
Abstract: The toxic factor secreted by killer strains of yeast and its effects on sensitive strains have been explored in detail.
109 citations
TL;DR: The lethal and cytoplasmic mutagenic effects of 52°C incubation during the cell cycle of a haploid strain of Saccharomyces cerevisiae were examined and only one mutants showed a greater thermosensitivity than the corresponding wild type.
Abstract: SummaryThe lethal and cytoplasmic mutagenic effects of 52°C incubation during the cell cycle of a haploid strain of Saccharomyces cerevisiae were examined. Both effects varied periodically in a rather parallel pattern: the maximum thermosensitivity was seen at budding time, corresponding to the S period (Williamson, 1965). The 52°C induction of a nuclear forward mutation was also examined: canavanine-resistant mutants were induced by this treatment. Exponentially growing cells were much more sensitive than resting cells to the different effects of heating which were studied. On the other hand, on comparing asynchronous cultures of 6 different radiosensitive mutants only one (xrs5) showed a greater thermosensitivity than the corresponding wild type.
103 citations
TL;DR: Four peaks of DNA-directed RNA polymerase activity are resolved by salt gradient elution of a sonicated yeast cell extract on DEAE-Sephadex, finding that all enzymes are more active with Mn(++) than with Mg(++) as divalent ion.
Abstract: Four peaks of DNA-directed RNA polymerase activity are resolved by salt gradient elution of a sonicated yeast cell extract on DEAE-Sephadex. The enzymes, which are named IA, IB, II, and III in order of elution, all appear to come from cell nuclei. Only enzyme II is sensitive to α-amanitin. All enzymes are more active with Mn++ than with Mg++ as divalent ion. Enzymes IB and II have salt optima in the range 0.05-0.10 M (NH4)2SO4, whereas enzyme III is maximally active at 0.20-0.25 M (NH4)2SO4. With optimal salt concentration and saturating DNA, the template preference ratio, activity on native calfthymus DNA divided by activity on denatured calf-thymus DNA, is 2.2 for IB, 0.4 for II, and 3.5 for III. None of the yeast polymerases was inhibited by rifamycin SV. Rifamycin AF/013 effectively inhibited polymerases IB, II, and III.
90 citations
TL;DR: In this paper, the authors identified the strain (B 111-1) showing the highest lytic activity as Arthrobacter luteus, and the optimum pH for lysis of viable yeast cells was 7.0-8.0.
Abstract: Some organisms capable of lysing viable yeast cells were isolated from brewery sewage by the enrichment culture method by intermittent feeding with brewer's yeast. The strain (B 111-1) showing the highest lytic activity was identified as Arthrobacter luteus.The activity of Arthrobacter luteus, B 111-1, to lyse viable yeast cells appeared in the culture medium in the early stationary phase of the bacterial growth. The pattern of change in lytic activity during cultivation was different from those of β-1, 3-glucanase and protease activities suggesting that some additional factors are essential for the lysis of viable yeast cells.The pH value of culture medium during cultivation influenced the development of the activity considerably. The pH value first decreased and then increased with the appearance of lytic activity.The activity to lyse viable yeast cells developed adaptively when the organism was cultivated in a medium containing yeast cells or β-1, 3-glucan, suggesting that the latter causes induction.Cell-free culture fluid of the organism showed a lytic activity- on cells of brewer's yeast at all stages of growth and on viable cells of yeast strains belonging to a wide range of genera. However, it did not lyse viable cells of the yeasts Rhodoturula, Pichia, and Hansenula, or viable and heat-treated cells of bacteria and molds.The lytic activity of the cell-free culture fluid was not lost by dialysis. It was salted out at 0.395 saturation of ammonium sulfate and was lost on incubation at 60° for 5min. It was also inactivated by such protein denaturing agents as mercuric chloride, sodium laurylbenzene sulfonate, and silver nitrate, indicating that the lytic activity was due to enzymes. The optimum pH for lysis of viable yeast cells was 7.0-8.0. The lytic activity was relatively stable between pH 5 and 10.
90 citations
TL;DR: Sedimentation analysis of nuclear DNA released from spheroplasts of the yeast Saccharomyces cerevisiae indicates that it has a number average molecular weight, and it is proposed that each yeast chromosome contains a single DNA duplex.
Abstract: Sedimentation analysis of nuclear DNA released from spheroplasts of the yeast Saccharomyces cerevisiae indicates that it has a number average molecular weight of 6.2 × 108. The chromosomal DNA molecules range in size from as small as 5 × 107 daltons to as large as 1.4 × 109 daltons. Based on these values and estimates of the total DNA content of the yeast nucleus, it is proposed that each yeast chromosome contains a single DNA duplex.
89 citations
TL;DR: In an investigation of the role of glucanases in modifying yeast cell walls at the location of new buds, vesicles derived from the endoplasmic reticulum, which are secreted locally into the cell wall of growing buds, and may be involved in the secretion of glucans, have been isolated.
Abstract: In an investigation of the role of glucanases in modifying yeast cell walls at the location of new buds, vesicles derived from the endoplasmic reticulum, which are secreted locally into the cell wall of growing buds, and may be involved in the secretion of glucanases, have been isolated.
86 citations
TL;DR: Comparison of the sequences of the cognate and non cognate tRNAs which are aminoacylated either by the yeast phenylalanyl- or valyl-tRNA synthetase led us to ascribe some importance to several regions inside of these t RNAs, for instance the dihydrouracil arm, the terminal part of the amino-acid acceptor stem and the extra-loop.
Abstract: It has been found that purified phenylalanyl- and valyl-tRNA synthetases from yeast catalyse the mischarging of numerous heterologous Escherichia coli and even of homologous yeast tRNAs when special aminoacylation conditions are used. For instance E. coli tRNAAla, tRNAVal, tRNALys and yeast tRNAAla, tRNAVal can be incorrectly aminoacylated by yeast phenylalanyl-tRNA synthetase, whereas E. coli tRNAAla, tRNAMet, tRNAIle, tRNAThr and yeast tRNAAla, tRNAPhe can be mischarged by yeast valyl-tRNA synthetase. The production of errors is highly dependant on the experimental conditions used, as their number and their level is increased when the Mg2+/ATP ratio or the enzyme concentration in the medium is increased or when the reactions are performed in the presence of dimethylsulfoxide. In the case of phenylalanyl-tRNA synthetase, conditions can be found where practically all E. coli tRNAs are wrongly aminoacylated, although at different levels. On the other hand, in the case of homologous systems some errors can only be detected when purified tRNAs are used, thus suggesting, when total tRNA is used, a competition between the cognate and non-cognate tRNAs which minimises the mischarging.
The comparison of the sequences of the cognate and non cognate tRNAs which are aminoacylated either by the yeast phenylalanyl- or valyl-tRNA synthetase led us to ascribe some importance to several regions inside of these tRNAs, for instance (a) the dihydrouracil arm, (b) the terminal part of the amino-acid acceptor stem and (c) the extra-loop. These regions should be essentially necessary for the establisment of the correct tri-dimensional conformation necessary for the recognition by the aminoacyl-tRNA synthetases.
81 citations
TL;DR: G + C-rich “molecules” have been isolated from the bulk of mitochondrial DNA by virtue of their lower elution molarity from hydroxyapatite, thus providing the first evidence that yeast mitochondrial DNA has an “intermolecular” compositional heterogeneity at a size level of about 1.5 × 106 daltons.
TL;DR: Throughout the secretion of acid phosphatase, and also after its termination, a small amount of enzyme remains firmly bound to the protoplasts, even after lysis, suggesting that this membrane-bound fraction remains constant.
TL;DR: RNase and alkaline digests of the mit[ 3 H]valyl-tRNA-mit-DNA hybrid yielded [ 3 H ]valyladenosine and [ 3H]valine, respectively, providing further evidence for the validity of the hybridization system.
TL;DR: β-Fructofuranosidase (but not acid phosphatase) was found to be a convenient marker for studying changes in the wall structure of yeast, and appears to be endohydrolases in their action pattern.
TL;DR: When after heat treatment at 52°, yeast cells are held in water at 28° with aeration for 24 hours to 5 days before plating, their survival is greatly enhanced in comparison to what is obtained on immediate plating.
Abstract: When after heat treatment at 52°, yeast cells are held in water at 28° with aeration for 24 hours to 5 days before plating, their survival is greatly enhanced in comparison to what is obtained on immediate plating. Moreover, the frequency of induced nuclear (canavanine-sensitivity to canavanine-resistance) and cytoplasmic (ϱ+ to ϱ−) mutants decreases in these conditions of liquid holding. This recovery from potentially lethal and mutagenic damage, induced by heat treatment, is blocked if the cells are stored at 4° or in the presence of protein synthesis inhibitors, implying that active metabolism is required for recovery.
TL;DR: The RNA polymerases from yeast have, in general, many properties in common with the corresponding enzymes of multicellular organisms.
Abstract: A procedure for the large-scale purification of yeast RNA polymerases A and B is described. The final enzyme preparations obtained are fairly homogeneous, as revealed by electrophoresis in polyacrylamide gels containing sodium dodecylsulfate. Both enzymes contain two large subunits with molecular weights of about 190000 and 135000 for polymerase A and 175000 and 140000 for polymerase B in a 1:1 ratio. The third polymerase from yeast (enzyme C) has not yet been sufficiently purified to determine its subunit structure. All three RNA polymerases require four ribonucleoside triphosphates, DNA and Mn2+ for activity. Denatured DNA is preferred over native DNA as template. Ammonium sulfate in low concentrations (20 to 50 mM) stimulates the enzyme activities two to three-fold; high concentrations are inhibitory. Only RNA polymerase 3 is sensitive towards α-amanitin. This enzyme is almost totally inhibited by a concentration of 100 μg/ml of the drug, whereas polymerases A and C remain virtually unaffected even at high concentrations of α-amanitin. The RNA polymerases from yeast have, in general, many properties in common with the corresponding enzymes of multicellular organisms.
TL;DR: Yeast cells contain approximately 1010 daltons of DNA per haploid nucleus, distributed among sixteen to eighteen genetically recognizable linkage groups, so the exact number of chromosomes in yeast remains uncertain.
Abstract: YEAST cells contain approximately 1010 daltons of DNA per haploid nucleus1, distributed among sixteen to eighteen genetically recognizable linkage groups2. During mitotic division no distinct condensation of chromosomal material occurs3, so that the exact number of chromosomes in yeast remains uncertain.
TL;DR: Binding studies show that both enzymes have two lysine sites and two ATP sites, but in contrast to this the valine:tRNA ligase contains only one polypeptide chain and has one site each for valine and ATP per enzyme molecule.
TL;DR: A new species of double-stranded RNA has been detected in certain strains of bakers' yeast, Saccharomyces cerevisiae, during investigations of the chemical nature of the cytoplasmic genetic determinants concerned with the killer character in yeast.
Abstract: A NEW species of double-stranded RNA has been detected in certain strains of bakers' yeast, Saccharomyces cerevisiae, during investigations of the chemical nature of the cytoplasmic genetic determinants concerned with the killer character in yeast. There are three phenotypes with respect to this killer phenomenon: killer, sensitive and neutral. Killer cells kill sensitive cells by secreting into the medium a toxic polypeptide1,2 to which they themselves are immune. Neutral cells neither kill nor are killed. The phenomenon is under the control of at least one nuclear gene and two types of cytoplasmic determinant, (k) and (n), which confer the killer and neutral phenotypes respectively3–5.
TL;DR: One of the DNase activities identified in yeast mitochondria is active on double stranded DNA at neutral pH and stimulated by Ethidium Bromide and other DNA intercalating drugs, which could be responsible for the yeast mitochondrial DNA degradation induced during mutagenesis by Ethium Bromide.
TL;DR: The beta-fructofuranosidase in live cells and in ethylacetatetreated cells exhibited polydispersity in heat inactivation susceptibility; but the kinetics were indistinguishable, and facile release by mechanical disruption was shown in both cases.
Abstract: After 16 hr of incubation in a low-phosphate, aerated medium, bakers' yeast was obtained with a high titer of acid phosphatase (EC 3.1.3.2) and beta-fructofuranosidase (EC 3.2.1.26). All of the beta-fructofuranosidase and 75% of the acid phosphatase were easily released by mechanical disruption in a French pressure cell. The cell wall suffered a limited number of cracks, but this was sufficient for the co-release of these enzymes. Both enzymes were subject to autolytic release, although correlation was inconclusive because of the relative instability of acid phosphatase. The data are consistent with the bulk of the two enzymes being located in the periplasmic space. Ethylacetate treatments yielded ghosts with high beta-fructofuranosidase but low acid phosphatase activities. The surviving acid phosphatase was not representative of that in live cells. It was resistant to release by mechanical disruption and showed a high susceptibility to heat inactivation. The beta-fructofuranosidase in live cells and in ethylacetatetreated cells exhibited polydispersity in heat inactivation susceptibility; but the kinetics were indistinguishable, and facile release by mechanical disruption was shown in both cases.
TL;DR: The primary structure of the second major species of arginine-tRNA, tRNAp, is presented, which has been obtained recently with a pi&cation of 80% and has been isolated and sequenced in the laboratory.
TL;DR: It appears that the mito-ADH band could be produced from physiologically competent mitochondria by mechanical disruption or by treatment with detergents, and substantiates the thesis that ADH-I is produced constitutively and thatADH-II is regulated via catabolite repression.
Abstract: Isozymes of alcohol dehydrogenase (ADH) from yeast were separated by discontinuous electrophoresis. Three major bands were observed: ADH-I, ADH-II, and a new band designated mito-ADH. Work with isolated mitochondria showed that the mito-ADH band could be produced from physiologically competent mitochondria by mechanical disruption or by treatment with detergents.The isozyme pattern was determined for the various physiological states of yeast growing anaerobically and aerobically on 2% glucose and aerobically on 2% ethanol, and for catabolite de-repressed cells undergoing an anaerobic → aerobic transition in continuous culture.The changing isozyme pattern substantiates the thesis that ADH-I is produced constitutively and that ADH-II is regulated via catabolite repression. It appears from the data that mito-ADH is more closely related to mitochondriogenesis than is ADH-II.
TL;DR: Phenylalanine ammonia-lyase from the yeast Sporobolomyces pararoseus was purified to near homogeneity as judged by disk gel electrophoresis and dehydroalanine was shown to be present and essential for catalysis.
TL;DR: This method has been shown to yield decryptified cells which allow the determination of rapidly changing enzyme levels in yeast suspensions of less than 1.5 mg wet weight/ml of cells.
TL;DR: The hypothesis that an artificial proteolytic cleavage is responsible for the observed two-chain pattern with the Saccharomyces enzyme is proposed and experimental evidence for this hypothesis is given in the following paper.
Abstract: The subunit structure of cytochrome b2 prepared from the yeast Hansenula anomala has been studied and compared to known data concerning the homologous enzyme prepared from ordinary bakers' yeast Saccharomyces cerevisiae. By high-speed equilibrium ultracentrifugation, the molecular weight has been determined as 236000 ± 10000, while subunits of 58000 ± 5000 are observed either in 6 M guanidine under reducing conditions or in 0.01 M phosphate. By electrophoresis in 6 M urea as well as in dodecylsulfate-mercaptoethanol, this subunit behaves as a single component. In crystalline enzyme preparations from bakers' yeast, the same unit is known to be made up of two chains of about 21000 and 36000 molecular weight. The hypothesis that an artificial proteolytic cleavage is responsible for the observed two-chain pattern with the Saccharomyces enzyme is proposed. Experimental evidence for this hypothesis is given in the following paper.
TL;DR: All the detectable sterols of yeast (Saccharomyces cerevisiae) with polarities (as measured by their RF values on silica gel)⩽ ergosta-5,7,22,24(28)-teraen-3β-ol have been isolated and characterised and lanosterol has been shown to be a mixture.
Abstract: All the detectable sterols of yeast (Saccharomyces cerevisiae) with polarities (as measured by their RF values on silica gel)⩽ ergosta-5,7,22,24(28)-teraen-3β-ol have been isolated and characterised. In addition to the known fully defined sterols, lanosterol. 14-demethyl-lanosterol, 4α-methylzymosterol, 24,25-dihydro-4α-methyl-24-methylenezymosterol, zymosterol,5,6-dihydroergosterol, ergosta-5,7,22,24(28)-tetraen-3β-ol, and ergosterol, the less well characterised sterols, fecosterol and episterol, have been reisolated and the structures confirmed. Sterols previously unreported in yeast, parkeol, ergost-7-en-3β-ol, ergosta-7,22,24(28)-trien-3β-ol, and ergosta-5,7,24(28)-trien-3β-ol have also been isolated and characterised. Ascosterol has been shown to be a mixture.