L'hydrolyse des hétérosides terpéniques du Muscat a petits grains par les enzymes périplasmiques de Saccharomyces cerevisiae

OENO One ◽  
1988 ◽  
Vol 22 (3) ◽  
pp. 189 ◽  
Author(s):  
Philippe Darriet ◽  
Jean-Noël Boidron ◽  
Denis Dubourdieu
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Yeast Cell ◽  
Cell Walls ◽  
Yeast Cells ◽  
Periplasmic Space ◽  
Enzymatic Extract ◽  
Periplasmic Extract ◽  
Glucosidase Activity ◽  
Aroma Precursors ◽  
Hydrolysis Of

<p style="text-align: justify;">Osidases located in periplasmic space of <em>Saccharomyces cerevisiae</em> are able to hydrolyse monoterpenes heterosides of Muscat grapes. To prepare the periplasmic extract, yeast cell walls are digested with <em>Zymolyase</em> in the presence of an osmotic protector to prevent lysis of the resulting protoplasts; periplasmic enzymes are liberated into the supernatant medium. Monoterpenes heterosides are incubated 48 or 72 hours at 25° C with either intact yeast cells or periplasmic enzymatic extract. Monoterpenes, especially gerianol and nerol, are liberated in these conditions. β-glucosidase activity seems to play an important rôle in these reactions.</p><p style="text-align: justify;">Fungal extracellular β-glucosidases are commonly strongly inhibited by glucose. Surprisingly, the activity of periplasmic yeast β-glucosidase is quite glucose independant. These results suggest that some periplasmic enzymes from yeast may be involved in the hydrolysis of varietal aroma precursors in wines.</p>

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.

scholarly journals Selection of Bacillus subtilis strains capable of producing β-glucanase supporting the hydrolysis of yeast cell walls

2020 ◽  
Vol 3 (1) ◽  
pp. 103
Author(s):  
Le Van Kien ◽  
Hanh Van Vu ◽  
Anh Tuan Ho ◽  
Hoai Thi Thu Pham ◽  
Huong Thi Mai Nguyen ◽  
...  
Keyword(s):  
Yeast Cell ◽  
Cell Walls ◽  
Yeast Cells ◽  
Broth Culture ◽  
Diffusion Method ◽  
Affecting Factors ◽  
Culture Time ◽  
Hydrolysis Of ◽  
Beer Yeast ◽  
Selection Of

The selection of B. subtilis strains was carried out with 15 strains from the collections of the Vietnam National University of Agriculture and the University of Economic and Technical Industries, Hanoi, Vietnam. To investigate the specific ability of β-glucanase in supporting the hydrolysis of beer yeast cells, CMC substrates in enzyme-activated test media of traditional methods was replaced by yeast cell walls in this study. The B. subtilis strains were activated on Nutrient Broth culture and then transplanted into MT3 culture for producing β-glucanase. Optical density (OD600nm) measurement was used to estimate the bacterial density. The β-glucanase activity formed by bacteria cells free supernatant was quantified by agar diffusion method on the enzyme-activated test media MT4. Two B. Subtilis strains , BG21 and BG15, were selected based on their largest clear-zones on agar plates. By modifying the values of the affecting factors and keeping the remaining influencing factors unchanged, it was determined that the B. subtilis BG21 and BG15 strains produced the highest biomass at the conditions of the culture time of 24 and 28 h, at pH 7.0, and at 37oC, respectively; furthermore, the highest activity of β-glucanase of the two strains BG21 and BG15 was exhibited at the culture time of 52 and 56 h, at pH 7.0, and at 37oC, respectively.Practical applicationsBacillus subtilis strains with the highest β-glucanase producing ability will be used for the production of biological products containing B. subtilis and β-glucanase which supports the hydrolysis of the beer yeast cells in the production of pig feed.

scholarly journals ENCAPSULATION OF LACTOBACILLUS ACIDOPHILUS IN YEAST CELL WALLS (SACCHAROMYCES CEREVISIAE) FOR IMPROVING SURVIVAL IN GASTROINTESTINAL CONDITIONS

2016 ◽  
Vol 54 (4) ◽  
pp. 533
Author(s):  
Le Nguyen Han ◽  
Le Huynh Hong Van ◽  
Tran Van Duc ◽  
Dong Thi Anh Dao
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Yeast Cell ◽  
Cell Walls ◽  
Free Cell ◽  
Yeast Cells ◽  
Extreme Condition ◽  
Cell Contact ◽  
Health Products ◽  
Quality Health ◽  
Direct Cell

In search of high-quality health products, it is required that probiotic preparations consumed in gastro-intestinal condition remain metabolically active and preserve their activity. Several recent studies, consequently, have focused on probiotic protection via encapsulation in order to optimize probiotics’ viability as well as their delivery into gastro-intestinal environment. The objectives of this study were to find out a new material for encapsulation of probiotics, utilizing capsules prepared from Saccharomyces cerevisiae to protect living probiotic cells. The encapsulation of cells was achieved, using the crack scars of the yeast cell walls (YCW) created by the sonication method. Besides, some probiotic cells can be considered as being encapsulated by some surrounded yeast cells by direct cell-cell contact. It is concluded that thanks to encapsulation by yeast cells, probiotic’s metabolic activity and survival are markedly improved. This suggests a high potential in protecting probiotics from the extreme condition of digestion process and can be applied in protecting probiotic preparations in food formulations as well. It was found that encapsulation yield in this study reached its highest point at 82.008 ± 1.123%. Viability of encapsulated probiotic in simulated gastric juice (SGJ) after 150 minutes is 19.048 ± 2.701%, compared to that of free cells at 0%. Likewise, after a 4-hour treatment in simulated intestinal juice (SIJ) (0.5% bile salt) encapsulated probiotic proves better survival at 56.338 ± 5.094% than free cell at 43.677 ± 2.058%.

scholarly journals Interactions of Surfactant Proteins A and D with Saccharomyces cerevisiae and Aspergillus fumigatus

2001 ◽  
Vol 69 (4) ◽  
pp. 2037-2044 ◽  
Author(s):  
Martin J. Allen ◽  
Dennis R. Voelker ◽  
Robert J. Mason
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Aspergillus Fumigatus ◽  
Cell Walls ◽  
Specific Interaction ◽  
Surfactant Proteins ◽  
Yeast Cells ◽  
Calcium Dependent ◽  
Before And After ◽  
Carbohydrate Polymer ◽  
Defense Molecules

ABSTRACT Surfactant proteins A (SP-A) and D (SP-D) are members of the collectin family of calcium-dependent lectins and are important pulmonary host defense molecules. Human SP-A and SP-D and rat SP-D bind to Aspergillus fumigatus conidia, but the ligand remains unidentified. To identify a fungal ligand for SP-A and/or SP-D, we examined the interactions of the proteins with Saccharomyces cerevisiae. SP-D but not SP-A bound yeast cells, and EDTA inhibited the binding. SP-D also aggregated yeast cells and isolated yeast cell walls. Treating yeast cells to remove cell wall mannoprotein did not reduce SP-D binding, and SP-D failed to aggregate chitin. However, SP-D aggregated yeast glucan before and after treatment with a β(1→3)-glucanase, suggesting a specific interaction between the collectin and β(1→6)-glucan. In support of this idea, SP-D-induced yeast aggregation was strongly inhibited by pustulan [a β(1→6)-linked glucose homopolymer] but was not inhibited by laminarin [a β(1→3)-linked glucose homopolymer]. Additionally, pustulan but not laminarin strongly inhibited SP-D binding to A. fumigatus. The pustulan concentration for 50% inhibition of SP-D binding to A. fumigatus is 1.0 ± 0.3 μM glucose equivalents. Finally, SP-D showed reduced binding to the β(1→6)-glucan-deficient kre6 yeast mutant. Taken together, these observations demonstrate that β(1→6)-glucan is an important fungal ligand for SP-D and that glycosidic bond patterns alone can determine if an extended carbohydrate polymer is recognized by SP-D.

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.

scholarly journals Purification of profilin from Saccharomyces cerevisiae and analysis of profilin-deficient cells.

1990 ◽  
Vol 110 (1) ◽  
pp. 105-114 ◽  
Author(s):  
B K Haarer ◽  
S H Lillie ◽  
A E Adams ◽  
V Magdolen ◽  
W Bandlow ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Wall ◽  
Actin Polymerization ◽  
Yeast Cells ◽  
Predicted Amino Acid Sequence ◽  
Temperature Sensitive ◽  
Wild Type ◽  
Yeast Saccharomyces Cerevisiae ◽  
Ellipsoidal Shape ◽  
Hydrolysis Of

We have isolated profilin from yeast (Saccharomyces cerevisiae) and have microsequenced a portion of the protein to confirm its identity; the region microsequenced agrees with the predicted amino acid sequence from a profilin gene recently isolated from S. cerevisiae (Magdolen, V., U. Oechsner, G. Müller, and W. Bandlow. 1988. Mol. Cell. Biol. 8:5108-5115). Yeast profilin resembles profilins from other organisms in molecular mass and in the ability to bind to polyproline, retard the rate of actin polymerization, and inhibit hydrolysis of ATP by monomeric actin. Using strains that carry disruptions or deletions of the profilin gene, we have found that, under appropriate conditions, cells can survive without detectable profilin. Such cells grow slowly, are temperature sensitive, lose the normal ellipsoidal shape of yeast cells, often become multinucleate, and generally grow much larger than wild-type cells. In addition, these cells exhibit delocalized deposition of cell wall chitin and have dramatically altered actin distributions.

scholarly journals Combined in silico and 19F NMR analysis of 5-fluorouracil metabolism in yeast at low ATP conditions

2019 ◽  
Vol 39 (12) ◽  
Author(s):  
Piotr H. Pawłowski ◽  
Paweł Szczęsny ◽  
Bożenna Rempoła ◽  
Anna Poznańska ◽  
Jarosław Poznański
Keyword(s):  
Oxidative Stress ◽  
Saccharomyces Cerevisiae ◽  
In Silico ◽  
31P Nmr ◽  
Yeast Cells ◽  
Atp Concentration ◽  
In Silico Modeling ◽  
Intracellular Metabolism ◽  
Hydrolysis Of ◽  
Careful Design

Abstract The cytotoxic effect of 5-fluorouracil (5-FU) on yeast cells is thought to be mainly via a misincorporation of fluoropyrimidines into both RNA and DNA, not only DNA damage via inhibition of thymidylate synthase (TYMS) by fluorodeoxyuridine monophosphate (FdUMP). However, some studies on Saccharomyces cerevisiae show a drastic decrease in ATP concentration under oxidative stress, together with a decrease in concentration of other tri- and diphosphates. This raises a question if hydrolysis of 5-fluoro-2-deoxyuridine diphosphate (FdUDP) under oxidative stress could not lead to the presence of FdUMP and the activation of so-called ‘thymine-less death’ route. We attempted to answer this question with in silico modeling of 5-FU metabolic pathways, based on new experimental results, where the stages of intracellular metabolism of 5-FU in Saccharomyces cerevisiae were tracked by a combination of 19F and 31P NMR spectroscopic study. We have identified 5-FU, its nucleosides and nucleotides, and subsequent di- and/or triphosphates. Additionally, another wide 19F signal, assigned to fluorinated unstructured short RNA, has been also identified in the spectra. The concentration of individual metabolites was found to vary substantially within hours, however, the initial steady-state was preserved only for an hour, until the ATP concentration dropped by a half, which was monitored independently via 31P NMR spectra. After that, the catabolic process leading from triphosphates through monophosphates and nucleosides back to 5-FU was observed. These results imply careful design and interpretation of studies in 5-FU metabolism in yeast.

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