摘要:

AbstractHeat‐shock induction of heat‐shock protein genes is due to a specific promoter element (the heat‐shock element, HSE). This study usedlacZunder HSE control (HSE‐lacZ) to characterize HSE activity inSaccharomyces cerevisiaecells of different physiological states and differing genetic backgrounds.In batch fermentations HSE‐lacZinduction by heat shock was maximal in exponential growth, and showed marked decline with the approach to stationary phase. Expression in the absence of heat shock was unaffected by growth phase, indicating that the growth‐dependent expression of many yeast heat‐shock genes uses promoter elements in addition to the HSE. Heat‐induced expression was strongly influenced by the temperature at which cultures were grown. While basal, uninduced expression was constant during growth at different temperatures to 30°C, induction by transfer to 39°C was reduced by increases in growth temperature as low as 18–24°C. Maximal HSE‐lacZinduction (30‐ to 50‐fold) was in cultures grown at low temperatures (18–24°C), then heat shocked at 39°C. Ethanol was a poor inducer. Mutations having little effect on HSE‐lacZexpression included a respiratory petite;ubi4(which inactivates the polyubiquitin gene); alsoubc4andubc5(which each inactivate one of the ubiquitin ligases involved in degradation of aberrant protein).pep4‐3increased both basal and induced β‐galactosidase about two‐fold, probably because of slower

ISSN:0749-503X    

DOI:10.1002/yea.320070602

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractWe have analysed the chromatin structure of theade6gene ofSchizosaccharomyces pombeand its flanking regions both in the chromosome and in plasmids. The chromatin structure is independent of the chromosomal or extrachromosomal location. Theade6gene contains eight precisely positioned nucleosomes on the 5′ half, ‘not positioned’ nucleosomes around the 3′ end and a nuclease‐sensitive promoter region. Precisely positioned nucleosomes, but no nuclease‐sensitive region were also detected on theura4gene in the chromosome and on a plasmid. The results show thatS. pombechromosomal and extrachromosomal genes have chromatin structures similar to those ofS. cerevisiaeand higher

ISSN:0749-503X    

DOI:10.1002/yea.320070603

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractFlocculation characteristics of 42 flocculet strains ofSaccharomyces cerevisiaewere examined. Two entirely distinct ‘lectin‐like’ mechanisms of flocculation were distinguished by sugar, salt, and low pH inhibitions, protease sensitivity, and selective expression of flocculation. One group, termed Flo1 phenotype, was inhibited by mannopyranoses and contained all strains bearing known genes affecting flocculation. The other group, termed NewFlo phenotype, contained the majority of brewery ale strains and was inhibited by manno‐ and glucopyranoses. Detailed sugar‐inhibition work revealed the probable receptor identity of both Flo1 and NewFlo flocculation, as being non‐reducing termini of α‐(1–3)‐linked mannan side branches, two or three mannopyranose

ISSN:0749-503X    

DOI:10.1002/yea.320070604

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractDuring diauxic growth of yeast in glucose‐rich medium, the accumulation of trehalose started well after complete exhaustion of glucose from the medium. The accumulation of the disaccharide was concomitant with a resumption of cell growth on the ethanol accumulated in the medium, but not with a degrdation of glycogen which occurred as soon as glucose had been consumed. In contrast, in a mutant deficient in phosphoenlpyruvate carboxykinase, the synthesis of trehalose coincided exactly with the degradation of glycogen. Upon inoculation of stationary phase wild‐type cells into a glucose medium, the activites of trehalose‐6‐phosphate (Tre6P) synthase and Tre6P phosphatase dropped in parallel to reach only 15% of their initial values after 3 h, and only recovered their original values as cell re‐entered staionary phase. In the presence of cycloheximide, the decrease in Tre6P synthase and Tre6P phosphatase activities was restricted to 50–60%, the remaining decrease being inhibited by the drug. Furthermore, the reappearance of the enzyme activities following transfer of cells to an acetate medium was blocked by cycloheximide. It was also shown that loss of activity of these two enzymes required a combination of metabolizable sugars together with a nitrogen source. Low activities of Tre6P synthase and Tre6P phosphatase were measured in mutants with increased adenylate cyclase activity (RAS2ala18val19mutants). Moreover, derepression of these enzymes at the approach of stationary phase was prevented in apde2mutant when it was cultivated in the presence of exogenous cyclic nucleotide. The mechanism of this effect is not clear, but may involve a transcriptional regulation by cAMP of the genes encoding the

ISSN:0749-503X    

DOI:10.1002/yea.320070605

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractTo study cell‐cycle‐related variations in wall permeability ofSaccharomyces cerevisiae, two approaches were used. First, an asynchronous culture was fractionated by centrifugal elutriation into subpopulations containing cell of increasing size. The subpopulations represented different stages of the cell cycle as judged by light microscopy. Cell wall porosity increased when these subpopulations became enriched with budded cells. Secondly, synchronous cultures were obtained by releasingMATacells from alpha‐factor induced G1‐arrest. These cultures grew synchronously for at least two generations. The cell wall porosity incresed sharply in these cultures, shortly before buds became visible and was maximal during the initial stages of bud growth. It decreased in cells which had completed nuclear migration and before abscission of the bud had occurred. The porosity reached its lowest value during abscission and in unbudded cells.We examined the incorporation of mannoproteins into the wall during the cell cycle. SDS‐extractable mannoproteins were incorporated continuously. However, the incorporation of glucanase‐extractable mannoproteins, which are known to affect cell wall porosity, showed cyclic oscillations and reached its maximum after nuclear migration. This coincided with a rapid decrease in cell wall porosity, indicating that glucanase‐extractable mannoproteins might contribute to

ISSN:0749-503X    

DOI:10.1002/yea.320070606

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractPlasma membrane was isolated from the salt‐tolerant yeastZygosaccharomyces rouxiiand fromSaccharomyces cerevisiae. The ATPase in the plasma membrane ofZ. rouxiicells was a typical proton‐ATPase as judged by testing with various ATPase inhibitors. There were slight differences in the pH optima of activities and in the sensitivity to sodium chloride (NaCl) and potassium chloride (KCl) of the ATPase fromZ. rouxiiandS. cerevisiae. The specific ATPase activity fromZ. rouxiiwas higher in cells grown in a medium containing 2M‐NaCl than in those not containing NaCl. Noin vivoactivation by incubation with glucose was observed inZ. rouxiicells and the specific ATPase activity was independent of the growth phase, unlikeS. cerevisiae

ISSN:0749-503X    

DOI:10.1002/yea.320070607

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractThe use of proline as a nitrogen soucre causes hypersensitivity to 5‐fluoro‐orotic acid (5FOA) and allows up to 40‐fold less of this drug to be used to select for the loss ofURA3function inSaccharomyces cerevisiae. 5FOA hypersensitivity is presumably due to the absence of nitrogen catabolite repression when proline is substituted for (NH4)2SO4as a nitrogen source. There are two constraints to the use of the proline–5FOA combination: (1) S288c genetic background strains are hypersensitive to 5FOA when grown in proline as a nitrogen source but at least one other genetic background is resistant to low levels of 5FOA under these conditions. (2) The addition of some nutritional supplements confers phenotypic resistance to the 5FOA–proline co

ISSN:0749-503X    

DOI:10.1002/yea.320070608

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractWe describe a set of replicative, integrative and single‐stranded shuttle vectors constructed from the pUC19 plasmid that we use routinely in our experiments. They bear a yeast selectable marker:URA3,TRP1orLEU2. Replicative vectors carrying different yeast replication origins have been constructed in order to have plasmids based on the same construction with a high or low copy number per cell and with different mitotic stabilities. All the vectors are small in size, provide a high yield inEscherichia coliand efficiently transformSaccharomyces cerevisiae. These plasmids have many of the unique sites of the pUC19 multicloning region and many of them allow for the screening of plasmids with an insert by alpha‐complementation. The nucleotide sequence of each of them is completely kn

ISSN:0749-503X    

DOI:10.1002/yea.320070609

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractTheKluyveromyces lactistoxin is a heterotrimeric protein which irreversible arrests proliferation of sensitiveSaccharomyces cerevisiaecells in the G1 phase of the cell cycle. By expressing the γ subunit of the toxin in sensitive yeast cells from a conditional promoter, it was previously demonstrated that it alone is required for inhibition (Tokunagaet al. (1989).Nucleic Acids Res.17, 3435–3446). Here we show that, like native exogenous toxin, intracellular γ subunit expression promoters a striking arrest of sensitive cells in G1. However, unlike the G1 arrest caused by native toxin, that induced by the γ subunit alone does not result in reduced cellular viability and is fully and rapidly reversible, suggesting that the G1 arrest and the irreversibility of action may reflect different aspects of the toxin's interaction with sensitive cells. We have selected a large number ofS. cerevisiaemutants which are highly resistant to the toxin in order to study its mode of action in more detail. Complementation analysis demonstrated that all but one of the mutants were recessive and these defined four separate genes. Members of two complementation groups concurrently acquired resistance to intracellular γ subunit expression, suggesting that they contain a modified toxin target site. The other two genes appear to be required for entry of the γ subunit into the sensitive cell since these mutants, while refractory to exogenous toxin, were fully sensitive to intracellular γ subunit exp

ISSN:0749-503X    

DOI:10.1002/yea.320070610

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractDNA sequencing and analysis of genomic DNA using the polymerase chain reaction were used to demonstrate thatSOD1andERG11are adjacent genes inSaccharomyces cerevisiaeS288c and to establish the correct intergenic sequence of this segment on chromosome VIII.

ISSN:0749-503X    

DOI:10.1002/yea.320070611

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY