Showing papers on "Yeast published in 1971"
TL;DR: Yeast cells extracted with alkali and acetic acid revealed very thin cell envelopes with prominent bud scars in the shape of a shallow crater with a raised rim, which concluded that chitin is localized in a ring around the bud scar, sandwiched between two layers of glucan.
212 citations
TL;DR: In this article, 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.
145 citations
138 citations
TL;DR: The rates of release of 7 enzymes from bakers' yeast have been measured and the disruption process did not cause loss of activity of these enzymes.
Abstract: The rates of release of 7 enzymes from bakers' yeast have been measured. The disruption process did not cause loss of activity of these enzymes. The various operating pressures, temperatures, and initial yeast concentrations used did not affect the rates of enzyme release relative to protein release. The release of acid phosphatase and invertase was faster than the overall protein release. Alcohol, glucose-6-phosphate, and 6-phosphogluconate dehydrogenases were released slightly faster or at the same rate as the overall protein and alkaline phosphatase and fumarase were released more slowly. These observations correlate well with the reported locations of these enzymes in the yeast cell.
121 citations
TL;DR: The hydroxylation activity and the content of both cytochrome P-450 and TPNH-cytochrome c reductase were greatly enhanced in cells grown on hydrocarbon, indicating that at least two components are required for maximal activity.
118 citations
TL;DR: The activity of acid and alkaline phosphatase in baker's yeast is de-repressed when the organisms are starved of phosphate, and it is suggested that these two enzymes share a common genetic and structural component.
Abstract: SUMMARY: The activity of acid and alkaline phosphatase in baker's yeast is de-repressed when the organisms are starved of phosphate. Mutants lacking phosphatase activity and mutants with constitutive phosphatase synthesis were isolated. In all of them acid and alkaline phosphatases were affected simultaneously. Nevertheless, characterization of these two enzymes by sensitivity to inhibition by orthophosphate, temperature inactivation, proteolytic digestion and cation dependence showed that they were clearly distinct. It is suggested that these two enzymes share a common genetic and structural component.
105 citations
TL;DR: The observations show that H(+) and, in certain circumstances, K(+) are co-substrates in the transport of the amino acid carrier to the transduction of chemical energy in an associated ion pump forming part of the mechanism for transporting amino acids into the yeast.
Abstract: 1. Proton uptake into the yeast Saccharomyces carlsbergensis, was studied at pH4.5–5.5 in the presence of both antimycin and 2-deoxyglucose to inhibit energy metabolism. Previous work had shown that the cells then absorbed about 20nmol of glycine or l-phenylalanine against a considerable amino acid concentration gradient. The addition of the amino acid immediately stimulated the rate of uptake of protons two- to three-fold. About 2 extra equivalents of H+ accompanied a given amount of the amino acids into the yeast preparations exposed to the metabolic inhibitors for 2–4min and about 1.2 equivalents after 20min exposure. 2. Analogous observations were made during serial additions of glycine, l-phenylalanine, l-leucine and l-lysine to preparations lacking the metabolic inhibitors and deficient in substrates needed for energy metabolism. In fresh cellular preparations the influx of glycine was then closely coupled to a stimulated flow of 2.1 equiv. of H+ into the yeast. A similar number of K+ ions left the cells. About 30% of the extra protons was subsequently ejected from the yeast. Deoxyglucose and antimycin together inhibited the ejection of protons. When the yeast had been fed with glucose energy metabolism was stimulated and almost as many protons as were absorbed with the amino acid were apparently ejected again. 3. Yeast preparations containing Na+, instead of K+, as the principal cation absorbed about 1 extra equivalent of H+ after the addition of phenylalanine, glycine or leucine. This response was not observed in the presence of both deoxyglucose and antimycin. 4. The observations show that H+ and, in certain circumstances, K+ are co-substrates in the transport of the amino acids into the yeast. An analogy is drawn with the roles of Na+ and K+ as co-substrates in certain mammalian systems. The results lead to various models relating the physical flow of the co-substrate ions on the amino acid carrier to the transduction of chemical energy in an associated ion pump forming part of the mechanism for transporting amino acids into the yeast.
104 citations
TL;DR: It is inferred that the ionic interaction between membrane lipids and membrane proteins is detectable byspin labels and the apparent “fluidity” of membranes detectable by spin labels requires re-evaluation.
104 citations
TL;DR: It is concluded that cardiolipin content of yeast is correlated with, and is a good indicator of, the state of development of mitochondrial membrane.
Abstract: The phospholipid composition of various strains of the yeast, Saccharomyces cerevisiae, and several of their derived mitochondrial mutants grown under conditions designed to induce variations in the complement of mitochondrial membranes has been examined. Wild type and petite (cytoplasmic respiratory deficient) yeasts were fractionated into various subcellular fractions, which were monitored by electron microscopy and analyzed for cytochrome oxidase (in wild type) and phospholipid composition. 90% or more of the phospholipid, cardiolipin was found in the mitochondrial membranes of wild type and petite yeast. Cardiolipin content differed markedly under various growth conditions. Stationary yeast grown in glucose had better developed mitochondria and more cardiolipin than repressed log phase yeast. Aerobic yeast contained more cardiolipin than anaerobic yeast. Respiration-deficient cytoplasmic mitochondrial mutants, both suppressive and neutral, contained less cardiolipin than corresponding wild types. A chromosomal mutant lacking respiratory function had normal cardiolipin content. Log phase cells grown in galactose and lactate, which do not readily repress the development of mitochondrial membranes, contained as much cardiolipin as stationary phase cells grown in glucose. Cytoplasmic mitochondrial mutants respond to changes in the glucose concentration of the growth medium by variations in their cardiolipin content in the same way as wild type yeast does under similar growth conditions. It is concluded that cardiolipin content of yeast is correlated with, and is a good indicator of, the state of development of mitochondrial membrane.
91 citations
74 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 glucAnases, 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. In yeast, exo-β-1,3-glucanase (EC 3.2.1.6) is present both extra- and intracellularly. Exponentially growing cells contain about 16% of the enzyme activity intracellularly (within the plasmalemma). Most, if not all, of this intracellular glucanase is sedimentable. Of the three classes of subcellular particles that contain glucanase, one is almost completely absent from stationary phase cells and almost absent from cells of the late budding phase of the budding cycle. These particles were isolated from budding cells by combined differential and density gradient centrifugation. They contain exo- and endo-β-1,3-glucanases, mannan, and protein. The isolate consists mainly of membrane-bounded particles with diameters corresponding to those of the secretory vesicles observed in situ . It is concluded that these particles are identical with the vesicles derived from the endoplasmic reticulum.
TL;DR: Evidence is presented for the first time demonstrating the incorporation of 2-DG into yeast cell wall material and showing that S. cerevisiae grown in the presence of 1-deoxy-d-glucose formed weakened cell walls responsible for the osmotic fragility.
Abstract: The growth inhibition and the lysis of Saccharomyces cerevisiae caused by 2-deoxy-d-glucose (2-DG) were shown to be a consequence of unbalanced cellular growth and division. The lysis, but not the repression of growth and osmotic fragility of cells, could be suppressed by the addition of mannitol as an osmotic stabilizer. This result, as well as the morphological changes observed in the cells and changes in the chemical composition of the cell walls, showed that S. cerevisiae grown in the presence of 2-DG formed weakened cell walls responsible for the osmotic fragility. Evidence is presented for the first time demonstrating the incorporation of 2-DG into yeast cell wall material. Other data suggest that the inhibition of yeast growth by 2-DG results from an interference of phosphorylated metabolites of 2-DG with metabolic processes of glucose and mannose involved in the synthesis of structural cell wall polysaccharides.
TL;DR: Although cycloheximide and 2-deoxy-d-glucose exert their action at two different points in the biosynthesis of glycoproteins, either of them can stop the process of synthesis and secretion of yeast invertase.
Abstract: The effect of cycloheximide and 2-deoxy-d-glucose on the synthesis and secretion of invertase by yeast cells and protoplasts has been studied Two yeast strains were used: Saccharomyces 303-67, whose investase synthesis is repressed by glucose, and a mutant of it, Saccharomyces FH4C, which is only partially affected by high levels of glucose in the incubation media For both strains the optimum glucose concentration is approximately 10 mM
Cycloheximide inhibited the synthesis of invertase in cells and protoplasts The secretion of the enzyme by the protoplasts was inhibited to a similar extent Parallel results were obtained with 2-deoxy-d-glucose
Two forms of invertase are present in yeast protoplasts; a light form devoid of carbohydrate and a heavy form which contains carbohydrate and is readily secreted In all experimental conditions studied the relative amount of both forms remained constant This indicates that although cycloheximide and 2-deoxy-d-glucose exert their action at two different points in the biosynthesis of glycoproteins, either of them can stop the process of synthesis and secretion of yeast invertase
TL;DR: Yast cells are treated with a mercaptan compound and EDTA, whereby the cell wall is made more sensitive to the attack of lytic enzymes, and the cell walls are digested with snail gut juice to facilitate the subsequent attack by the snail enzymes.
Abstract: Publisher Summary Yeast cells are treated with a mercaptan compound and EDTA, whereby the cell wall is made more sensitive to the attack of lytic enzymes. The cell wall is then digested with snail gut juice. An osmotic stabilizer must be present during incubation to prevent bursting of the spheroplasts. The pretreatment with SH compounds and EDTA greatly facilitates the subsequent attack by the snail enzymes. Cells from the stationary phase are converted completely to spheroplasts. An appropriate amount of enzyme must be ascertained for each strain of yeast. For logarithmic phase cells of Saccharomyces carlsbergensis ( S. carlsbergensis ), a volume of enzyme corresponding to about 0.3 ml of the original “glusulase” is usually sufficient to convert 1 g of yeast (wet weight) into spheroplasts in 45 minutes. The spheroplast preparation may be contaminated with numerous bud scars, at least if “glusulase” is used as source of lytic enzymes. The bud scars consist mainly of chitin and are resistant to the attack of “glusulase,” which has only weak chitinase activity.
TL;DR: The metabolic fate of D -xylose taken up by Rhodotorula gracilis cells has been investigated and an enzyme activity appears, which was found in both the supernatant and the sediment of xylose-grown cell-free extract, but not in those of glucose-grown cells.
TL;DR: The centrat concept which the authors have wanted to exploit is the inherent ability of polynucleotide chains to form ordered bihelical complexes by virtue of base-pairing.
Abstract: The methodology developed for the synthesis of bihelical DNA consists of the following three steps. (1) Chemical synthesis of deoxyribopolynucleotide segments containing 8 to 12 nucleotide units. These should represent the entire two strands of the intended DNA and those belonging to the complementary strands should have an overlap of 4 to 5 nucleotides. (2) The phosphorylation ofthe 5' -hydroxyl group with ATP carrying a suitable label in the y-phosphoryl group using the T4 polynucleotide kinase. (3) The head-to-tail joining of the appropriate segments when they are aligned to form bihelical complexes using the T4 polynucleotide ligase. U sing this methodology total synthesis of yeast alanine transfer RNA structural gene has been achieved. Methods have been developed in recent years for the chemical synthesis of deoxyribopolynucleotides of defined nucleotide sequence • • However, in practical terms, there is a severe Iimit on the length of the polynucleotide chains which can be assembled unambiguously by purely chemical methods. On the other band, for biological studies of the nucleic acids, it is often the high molecular weight nucleic acids which are the most useful. Therefore, it is desirable or even necessary to couple methods of organic chemistry, which alone can afford oligonucleotides of predetermined sequence, with other concepts or methods in order to prepare nucleic acids of defined nucleotide sequences. In earlier work reported from this laboratory, it was possible to prepare double-stranded DNA-like polymers of known repeating sequences by using short synthetic deoxypolynucleotides as templates for the DNA polymerases. The availability of the resulting polymers permitted extensive studies of the cell-free protein synthesis and of the genetic code • 1 . Clearly, a major aim of future synthetic work in the field of nucleic acids must be the development of methods for the synthesis of bihelical DNAs with specific nucleotide sequences. Towards this goal, the centrat concept which we have wanted to exploit is the inherent ability of polynucleotide chains to form ordered bihelical complexes by virtue of base-pairing. Thus, it was hoped to join relatively short chemically synthesized deoxyribopolynucleotides while * Present address: Departments of Chemistry and Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, U.S.A.
TL;DR: 3-Phosphoglycerate kinase has been isolated from yeast by a new procedure, and six distinct crystalline forms have been grown, at least one of these being suitable for X-ray diffraction studies.
Abstract: 3-Phosphoglycerate kinase has been isolated from yeast by a new procedure. Over 1g was obtained from 450g of granulated baker's yeast; it had a specific activity of up to 940units/mg at 30°C. Six distinct crystalline forms have been grown, at least one of these being suitable for X-ray diffraction studies. The crystalline preparation is pure, judged by starch-gel or sodium dodecyl sulphate–polyacrylamide-gel electrophoresis; the latter method indicating that the enzyme is monomeric, with a molecular weight near to 50000.
TL;DR: Sensory examination of an aroma model consisting of alcohols, fatty acids, esters and aldehydes, in concentrations estimated in whisky, has proved that—in addition to vicinal diketones—esters predominate as components influencing the aroma, but also some fatty acids exercise a most marked influence.
Abstract: Sensory examination of an aroma model consisting of alcohols, fatty acids, esters and aldehydes, in concentrations estimated in whisky, has proved that—in addition to vicinal diketones—esters predominate as components influencing the aroma, but also some fatty acids exercise a most marked influence. Furthermore, some people possess a good ability to smell certain compounds whereas others cannot smell them as well, but detect other compounds more easily.
Within the group of more than 100 identified aroma components, mainly the same substances appear in the volatile aroma fraction of beer, wine and distilled beverages. In view of this, it seems evident that the raw materials utilized for the production of the beverages contribute to no more than a limited extent towards the aroma composition. The aroma components which are most noticeable are produced by the yeast during fermentation, and the nature of the final aroma first and foremost depends upon the kind of yeast used, and upon the fermentation conditions. Although the yeast for the most part produces the same aroma components also In different beverages, considerable variation may occur in the quantities of aroma components even in beverages of the same type.
The structure and function of the plasma membrane selectively regulate the uptake of different compounds from the medium into the yeast cell, and the release of the metabolites from the cell into the medium. In this sense, the lipid composition of the plasma membrane and its lipolytic enzymes may possess a decisive importance. The activity of the lipolytic enzymes present in the plasma membrane must be controlled by some regulatory mechanism. If this is the case, the permeability of the plasma membrane can be modified, e.g., by activation of the phospholipases, with consequent degradation of membrane phospholipids. Consequently, it is likely that one of the functions of the lipolytic enzymes present in the plasma membrane is that of participation in the transport processes by changing the permeability properties of the plasma membrane.
TL;DR: DTT-induced release of invertase by both yeasts was dependent on DTT concentration, pH, temperature, metal ions and yeast age, but these yeasts responded differently to oxidation and to release under suboptimal conditions.
Abstract: Summary: The rate of sphaeroplast formation from yeast was greater with dithiothreitol (DTT) in the reaction mixture than with 2-mercaptoethanol (2-ME) and the sphaeroplast population so produced was more rapidly and completely lysed in a non-isotonic environment. Incubation with DTT, but not 2-ME, allowed rapid formation of sphaeroplasts from yeast in stationary phase. DTT and 2-ME readily released invertase from Saccharomyces carlsbergensis, but only DTT released invertase from S. cerevisiae. DTT-induced release of invertase by both yeasts was dependent on DTT concentration, pH, temperature, metal ions and yeast age, but these yeasts responded differently to oxidation and to release under suboptimal conditions.
TL;DR: Aerobic yeast mitochondria contain a unique isozyme of alcohol dehydrogenase that accounts for the ability of yeast mitochondia to respire with ethanol as a substrate and differs from the classical, cytoplasmic isozyme by its slower electrophoretic mobility on polyacrylamide gel and its more alkaline pH optimum.
TL;DR: It is concluded that yeast mitochondrial tRNA(fMet), also known as fMet-tRNA, is a gene product of the mitochondrial genome.
Abstract: Formyltetrahydrofolic acid:methionyl-tRNA transformylase was isolated from Saccharomyces cerevisiae mitochondria and used to prepare yeast mitochondrial [3H]formylmethionyl-tRNA. This fMet-tRNA hybridizes with mitochondrial DNA but not with yeast nuclear or E. coli DNA. Unlabeled mitochondrial, but not extramitochondrial, tRNA competes in this reaction. tRNA was eluted from the hybrid and found to contain the label almost exclusively in fMet-tRNA. Yeast cytoplasmic fMet-tRNA formylated with Escherichia coli enzyme, and E. coli fMet-tRNA, do not hybridize with mitochondrial DNA. It is concluded that yeast mitochondrial tRNAfMet is a gene product of the mitochondrial genome.
TL;DR: Mitochondria isolated from these mutants retain resistance in vitro, even if the mitochondrial membrane is damaged by freezing and thawing and this led Linnane et al. to propose that resistance in these mutants is due to an altered mitochondrial ribosome.
TL;DR: A Saccharomyces strain has been described which carries the maltose gene, MAL4, and produces 15–500 fold more enzyme when grown in glucose than any other strain tested, and it has been suggested that hyper production of enzyme is a function of the Mal4 locus.
Abstract: SummaryA Saccharomyces strain (1403-7A) has been described which carries the maltose gene, MAL4, and produces 15–500 fold more enzyme when grown in glucose than any other strain tested. The factor responsible for this high basal level is genetically dominant and closely linked to or identical with the structural gene. Maltase produced by this strain has a different heat stability, specific activity, and michaelis constant from the maltase produced by another strain (1394-9B) carrying the MAL4 allele. It has been suggested that hyper production of enzyme is a function of the MAL4 locus and that structural alteration of the enzyme can occur in some strains at a post transcriptional level.
TL;DR: The yeast S-adenosyl methionine decarboxylase resembles a similar enzyme previously described in rat ventral prostate insofar as it is specifically enhanced by putrescine, and does not require Mg++ or any other dissociable metal cofactor.
TL;DR: The structure of aspartate-tRNA isolated from brewer's yeast is described and it is shown that it is one of the shortest tRNAs so far sequenced and has a pUp 5′ terminal sequence which has not yet been found in other sequenced t RNAs1–5.
Abstract: WE describe here the structure of aspartate-tRNA isolated from brewer's yeast. Fig. 1 shows that aspartate-tRNA is composed of seventy-five nucleotide residues including eight unusual nucleotides. It is one of the shortest tRNAs so far sequenced and has a pUp 5′ terminal sequence which has not yet been found in other sequenced tRNAs1–5. The 3′ terminal end is GCCAOH. This sequence has only previously been found in serine-tRNAs of yeast and rat liver.
TL;DR: A mechanistic model is presented for the growth kinetics of a yeast grown by submerged aerobic fermentation using a liquid hydrocarbon as sole carbon source and it is shown that for the case of relatively small oil droplets, the model predicts the present and previous experimental data for growth of yeasts in n‐alkane systems.
Abstract: A mechanistic model is presented for the growth kinetics of a yeast grown by submerged aerobic fermentation using a liquid hydrocarbon as sole carbon source. The model is based on the assumption that cell growth is governed by the extent of probable cell attachment at the hydrocarbon oil-droplet surfaces in a four-phase dispersion. An analytical expression has been developed for the model. It is shown that for the case of relatively small oil droplets, the model predicts the present and previous experimental data for growth of yeasts (Candida species) in n-alkane systems. The model is further examined for maximal growth in terms of substrate dilution rate and agitation power consumption for a continuous fermentation process.