scholarly journals The structure of a β-(1→6)-d-glucan from yeast cell walls

1973 ◽  
Vol 135 (1) ◽  
pp. 31-36 ◽  
Author(s):  
David J. Manners ◽  
Alan J. Masson ◽  
James C. Patterson ◽  
Håkan Björndal ◽  
Bengt Lindberg
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Yeast Cell ◽  
Cell Walls ◽  
Minor Component ◽  
Degree Of Polymerization ◽  
Chemical Fractionation ◽  
Yeast Saccharomyces Cerevisiae ◽  
A Minor ◽  
Branched Structure

By selective enzymolysis, or chemical fractionation, a minor polysaccharide component has been isolated from yeast (Saccharomyces cerevisiae) glucan. This minor component has a degree of polymerization of about 130–140, a highly branched structure, and a high proportion of β-(1→6)-glucosidic linkages. The molecules also contain a smaller proportion of β-(1→3)-glucosidic linkages that serve mainly as interchain linkages, but some may also be inter-residue linkages.

scholarly journals The structure of a β-(1→3)-d-glucan from yeast cell walls

1973 ◽  
Vol 135 (1) ◽  
pp. 19-30 ◽  
Author(s):  
David J. Manners ◽  
Alan J. Masson ◽  
James C. Patterson
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Molecular Weight ◽  
Yeast Cell ◽  
High Molecular Weight ◽  
Cell Walls ◽  
Minor Component ◽  
Yeast Saccharomyces Cerevisiae ◽  
Degree Of Branching ◽  
Degree Of Heterogeneity

Yeast glucan as normally prepared by various treatments of yeast (Saccharomyces cerevisiae) cell walls to remove mannan and glycogen is still heterogeneous. The major component (about 85%) is a branched β-(1→3)-glucan of high molecular weight (about 240000) containing 3% of β-(1→6)-glucosidic interchain linkages. The minor component is a branched β-(1→6)-glucan. A comparison of our results with those of other workers suggests that different glucan preparations may differ in the degree of heterogeneity and that the major β-(1→3)-glucan component may vary considerably in degree of branching.

scholarly journals Cell fusion in yeast is negatively regulated by components of the cell wall integrity pathway

2019 ◽  
Vol 30 (4) ◽  
pp. 441-452 ◽  
Author(s):  
Allison E. Hall ◽  
Mark D. Rose
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Death ◽  
Cell Wall ◽  
Yeast Cell ◽  
Cell Fusion ◽  
Cell Walls ◽  
Cell Wall Integrity ◽  
Fusion Genes ◽  
Cell Wall Degradation ◽  
Cell Wall Integrity Pathway

During mating, Saccharomyces cerevisiae cells must degrade the intervening cell wall to allow fusion of the partners. Because improper timing or location of cell wall degradation would cause lysis, the initiation of cell fusion must be highly regulated. Here, we find that yeast cell fusion is negatively regulated by components of the cell wall integrity (CWI) pathway. Loss of the cell wall sensor, MID2, specifically causes “mating-induced death” after pheromone exposure. Mating-induced death is suppressed by mutations in cell fusion genes ( FUS1, FUS2, RVS161, CDC42), implying that mid2Δ cells die from premature fusion without a partner. Consistent with premature fusion, mid2Δ shmoos had thinner cell walls and lysed at the shmoo tip. Normally, Cdc42p colocalizes with Fus2p to form a focus only when mating cells are in contact (prezygotes) and colocalization is required for cell fusion. However, Cdc42p was aberrantly colocalized with Fus2p to form a focus in mid2Δ shmoos. A hyperactive allele of the CWI kinase Pkc1p ( PKC1*) caused decreased cell fusion and Cdc42p localization in prezygotes. In shmoos, PKC1* increased Cdc42p localization; however, it was not colocalized with Fus2p or associated with cell death. We conclude that Mid2p and Pkc1p negatively regulate cell fusion via Cdc42p and Fus2p.

Cytochemical localization of some polysaccharide components in the cell walls of Chalara elegans during its life cycle

1992 ◽  
Vol 38 (8) ◽  
pp. 828-837
Author(s):  
Eliane Dumas-Gaudot ◽  
Abdessamad Tahiri-Alaoui ◽  
Nicole Benhamou
Keyword(s):  
Spatial Distribution ◽  
Cell Walls ◽  
Pathogenic Fungus ◽  
Minor Component ◽  
Multilayered Structure ◽  
Electron Microscope Level ◽  
Cytochemical Localization ◽  
Chalara Elegans ◽  
A Minor ◽  
First Time

The occurrence of polysaccharides and sugars in the cell walls of the soil-borne pathogenic fungus Chalara elegans (deuteromycete) has been investigated at the electron microscope level, using cytochemical approaches based on the affinity of lectin or enzyme–gold complexes for some carbohydrates. Evidence for the presence of both β-1,4-glucans and chitinous components is reported here for the first time in the cell walls of chlamydospores, endoconidia, and hyphae. A minor component with N-acetyl-D-galactosamine residues is also detected in the cell walls and, as a storage product, in the cytoplasm. The spatial distribution of both cellulosic β-1,4-glucans and N-acetylglucosamine residues differs according to the fungal cells, and the present results give a more accurate description of the multilayered structure of the fungal walls (i.e., chlamydospores and hyphae). Key words: Chalara elegans, fungi, cell walls, gold cytochemistry.

scholarly journals Synthesis of Triacylglycerols by the Acyl-Coenzyme A:Diacyl-Glycerol Acyltransferase Dga1p in Lipid Particles of the Yeast Saccharomyces cerevisiae

2002 ◽  
Vol 184 (2) ◽  
pp. 519-524 ◽  
Author(s):  
Daniel Sorger ◽  
Günther Daum
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Fatty Acids ◽  
Microsomal Fraction ◽  
Lipid Analysis ◽  
Minor Importance ◽  
Yeast Saccharomyces Cerevisiae ◽  
Fold Enrichment ◽  
Lipid Particles ◽  
A Minor ◽  
Minor Extent

ABSTRACT The terminal step of triacylglycerol (TAG) formation in the yeast Saccharomyces cerevisiae is catalyzed by the enzyme acyl-CoA:diacylglycerol acyltransferase (DAGAT). In this study we demonstrate that the gene product of YOR245c, Dga1p, catalyzes a major yeast DAGAT activity which is localized to lipid particles. Enzyme measurements employing a newly established assay containing radioactively labeled diacylglycerol (DAG) as a substrate and unlabeled palmitoyl-CoA as a cosubstrate revealed a 70- to 90-fold enrichment of DAGAT in lipid particles over the homogenate but also a 2- to 3-fold enrichment in endoplasmic reticulum fractions. In a dga1 deletion strain, the DAGAT activity in lipid particles is dramatically reduced, whereas the activity in microsomes is affected only to a minor extent. Thus, we propose the existence of DAGAT isoenzymes in the microsomal fraction. Furthermore, we unveiled an acyl-CoA-independent TAG synthase activity in lipid particles which is distinct from Dga1p and the phosphatidylcholine:DAGAT Lro1p. This acyl-CoA-independent TAG synthase utilizes DAG as an acceptor and free fatty acids as cosubstrates and occurs independently of the acyl-CoA synthases Faa1p to Faa4p. Based on lipid analysis of the respective deletion strains, Lro1p and Dga1p are the major contributors to total cellular TAG synthesis, whereas other TAG synthesizing systems appear to be of minor importance. In conclusion, at least three different pathways are involved in the formation of storage TAG in the yeast.

scholarly journals Extracellular pH and high concentration of potassium regulate the primary necrosis in the yeast Saccharomyces cerevisiae.

2021 ◽  
Author(s):  
Victoria Bidiuk ◽  
Alexander Alexandrov ◽  
Airat Valiakhmetov
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Death ◽  
Yeast Cell ◽  
Gene Mutations ◽  
Cellular Membrane ◽  
Extracellular Ph ◽  
Specific Gene ◽  
High Concentration ◽  
Yeast Saccharomyces Cerevisiae ◽  
Neutral Ph

Abstract Extracellular pH has a significant impact on the physiology of the yeast cell, but its role in cell death has not been thoroughly investigated. We studied the effect of extracellular pH on the development of primary necrosis in Saccharomyces cerevisiae yeast under two general conditions leading to cell death. The first is sugar induced cell death (SICD), and the second is death caused by several specific gene deletions, which have been recently identified in a systematic screen. It was shown that in both cases, primary necrosis is suppressed at neutral pH. SICD was also inhibited by the protonophore dinitrophenol (DNP) and 150 mM extracellular K+, with the latter condition also benefiting survival of cell dying due to gene mutations. Thus, we show that neutral pH can suppress different types of primary necrosis. We suggest that changes to the cellular membrane potential can play a central role in yeast cell death.

Killer Toxins of Yeasts: Inhibitors of Fermentation and Their Adsorption

1987 ◽  
Vol 50 (3) ◽  
pp. 234-238 ◽  
Author(s):  
FERDINAND RADLER ◽  
MANFRED SCHMITT
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Wall ◽  
Yeast Cell ◽  
Cell Walls ◽  
Killer Toxin ◽  
Yeast Cells ◽  
Toxin Concentration ◽  
Commercial Preparation ◽  
Killer Toxins ◽  
Original Amount

The killer toxin (KT 28), a glycoprotein of Saccharomyces cerevisiae strain 28, was almost completely adsorbed by bentonite, when applied at a concentration of 1 g per liter. No significant differences were found between several types of bentonite. Killer toxin KT 28 is similarly adsorbed by intact yeast cells or by a commercial preparation of yeast cell walls that has been recommended to prevent stuck fermentations. An investigation of the cell wall fractions revealed that the toxin KT 28 was mainly adsorbed by mannan, that removed the toxin completely. The alkali-soluble and the alkali-insoluble β-1,3- and β-1,6-D-glucans lowered the toxin concentration to one tenth of the original amount. The killer toxin of the type K1 of S. cerevisiae was adsorbed much better by glucans than by mannan.

Nuclear behaviour and cell wall composition in relation to budding in mutants of the yeast Saccharomyces cerevisiae

1986 ◽  
Vol 64 (1) ◽  
pp. 193-200 ◽  
Author(s):  
Mario Lachapelle ◽  
E. Roger Boothroyd
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Wall ◽  
Spindle Pole ◽  
Minor Role ◽  
Temperature Sensitive ◽  
Yeast Saccharomyces Cerevisiae ◽  
Bud Emergence ◽  
Spindle Elongation ◽  
10 Nm Filaments ◽  
A Minor

A temperature-sensitive, cell division cycle mutant (cdc24–1) and karyogamy-deficient (kar1) mutant of Saccharomyces cerevisiae, both of which can produce binucleate or multinucleate cells, were used to study certain aspects of budding, after fluorescent staining for mannan, chitin, and nuclei (DNA). In most binucleate cells the two nuclei lay close together and divided into the same bud. In a few, however, the nuclei were far apart and one or two buds were formed, each proximal to a nucleus. The proximity of daughter nuclei in most blocked cdc24–1 cells suggests a role for the CDC24 gene product in spindle elongation. The relationship between the nuclei and the number and location of buds supports the theory of a preponderant role for the nucleus in budding. Although buds develop preferentially in regions of low chitin content in kar1 heterokaryons, the ability of cdc24–1 cells to bud even with a uniformly high content of chitin and mannan suggests a minor role for these cell wall constituents in determining the sites of bud emergence. The chitin ring is not needed for bud emergence but seems to play a role in normal bud development and in septum formation. Electron microscopy of cdc24–1 cells blocked (37 °C) for 8 h and released (23 °C) for 30 min showed morphologically normal spindle pole bodies, cytoplasmic microtubules, and intranuclear spindles. Although the chitin ring was absent, the ring of 10-nm filaments was present, consistent with its proposed role in bud emergence.

scholarly journals Two Novel Techniques for Determination of Polysaccharide Cross-Links Show that Crh1p and Crh2p Attach Chitin to both β(1-6)- and β(1-3)Glucan in the Saccharomyces cerevisiae Cell Wall

2009 ◽  
Vol 8 (11) ◽  
pp. 1626-1636 ◽  
Author(s):  
Enrico Cabib
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Wall ◽  
Acetic Acid ◽  
Yeast Cell ◽  
Cell Walls ◽  
Double Mutant ◽  
The Other ◽  
Cross Links

ABSTRACT Previous work, using solubilization of yeast cell walls by carboxymethylation, before or after digestion with β(1-3)- or β(1-6)glucanase, followed by size chromatography, showed that the transglycosylases Crh1p and Crh2p/Utr2p were redundantly required for the attachment of chitin to β(1-6)glucan. With this technique, crh1Δ crh2Δ mutants still appeared to contain a substantial percentage of chitin linked to β(1-3)glucan. Two novel procedures have now been developed for the analysis of polysaccharide cross-links in the cell wall. One is based on the affinity of curdlan, a β(1-3)glucan, for β(1-3)glucan chains in carboxymethylated cell walls. The other consists of in situ deacetylation of cell wall chitin, generating chitosan, which can be extracted with acetic acid, either directly (free chitosan) or after digestion with different glucanases (bound chitosan). Both methodologies indicated that all of the chitin in crh1Δ crh2Δ strains is free. Reexamination of the previously used procedure revealed that the β(1-3)glucanase preparation used (zymolyase) is contaminated with a small amount of endochitinase, which caused erroneous results with the double mutant. After removing the chitinase from the zymolyase, all three procedures gave coincident results. Therefore, Crh1p and Crh2p catalyze the transfer of chitin to both β(1-3)- and β(1-6)glucan, and the biosynthetic mechanism for all chitin cross-links in the cell wall has been established.

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