Preparation of enantiomerically pure (R)-(1-hydroxyethyl)dimethyl(phenyl)silane using resting cells of Saccharomyces cerevisiae (DHW S-3) as biocatalyst

1995 ◽  
Vol 42 (5) ◽  
pp. 671-674 ◽  
Author(s):  
L. Fischer ◽  
S. A. Wagner ◽  
R. Tacke
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Resting Cells ◽  
Enantiomerically Pure

Net synthesis of sterols in resting cells of Saccharomyces cerevisiae

1954 ◽  
Vol 13 ◽  
pp. 591 ◽  
Author(s):  
Harold P. Klein ◽  
Norman R. Eaton ◽  
John C. Murphy
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Resting Cells

Synthesis and Structure Assignment of 2-(4-Methoxybenzyl)cyclohexyl β-D-Galactopyranoside Stereoisomers

2006 ◽  
Vol 71 (8) ◽  
pp. 1186-1198 ◽  
Author(s):  
David Šaman ◽  
Martina Wimmerová ◽  
Zdeněk Wimmer
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Nmr Analysis ◽  
Enantiomerically Pure ◽  
Structure Assignment

Several promoters were used in the Koenigs-Knorr synthesis of the title alkyl β-D-galactopyranosides, both in their diastereoisomeric forms (5a/5b and 6a/6b), resulting from the synthesis performed with the respective racemic cis and trans isomers of 2-(4-methoxybenzyl)cyclohexan-1-ol, and in their enantiomerically pure forms 5a and 6a, starting only from the (1S,2S)- and (1S,2R)-enantiomers of 2-(4-methoxybenzyl)cyclohexan-1-ol. The aim of the study was to find convenient modification(s) of the Koenigs-Knorr synthesis of alkyl β-D-galactopyranosides from more hindered and more complex 2-substituted cycloalkanols. Separation of the diastereoisomeric compounds using HPLC on a chiral Nucleodex-β-OH column was used to obtain small quantities of all possibly existing enantiomerically pure products for unambiguous structure assignment by NMR analysis. The (1S,2S)- and (1S,2R)- enantiomers of 2-(4-methoxybenzyl)cyclohexan-1-ol (1a and 2a) were prepared by a reduction of 2-(4-methoxybenzyl)cyclohexan-1-one with Saccharomyces cerevisiae in enantiomeric purities: ee = 98.5% ((1S,2S)-enantiomer (1a)), and ee ≥ 99% ((1S,2R)-enantiomer (2a)).

Mechanisms of appearance of the Pasteur effect in Saccharomyces cerevisiae: inactivation of sugar transport systems

1982 ◽  
Vol 152 (1) ◽  
pp. 19-25
Author(s):  
R Lagunas ◽  
C Dominguez ◽  
A Busturia ◽  
M J Sáez
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Nitrogen Source ◽  
Nitrogen Starvation ◽  
Sugar Transport ◽  
Regulatory Mechanisms ◽  
Transport Systems ◽  
Resting Cells ◽  
Catabolic Pathway ◽  
Pasteur Effect ◽  
Do So

Saccharomyces cerevisiae does not show a noticeable Pasteur effect (activation of sugar catabolism by anaerobiosis) when growing with an excess of sugar and nitrogen source, but it does do so after exhaustion of the nitrogen source in the medium (resting state). We have found that this different behavior of growing and resting S. cerevisiae seems due to differences in the contribution of respiration to catabolism under both states. Growing S. cerevisiae respired only 3 to 20% of the catabolized sugar, depending on the sugar present; the remainder was fermented. In contrast, resting S. cerevisiae respired as much as 25 to 100% of the catabolized sugar. These results suggest that a shift to anaerobiosis would have much greater energetic consequences in resting than in growing S. cerevisiae. In resting S. cerevisiae anaerobiosis would strongly decrease the formation of ATP; as a consequence, various regulatory mechanisms would switch on, producing the observed increase of the rate of glycolysis. The greater significance that respiration reached in resting cells was not due to an increase of the respiratory capacity itself, but to a loss of fermentation which turned respiration into the main catabolic pathway. The main mechanism involved in the loss of fermentation observed during nitrogen starvation was a progressive inactivation of the sugar transport systems that reduced the rate of fermentation to less than 10% of the value observed in growing cells. Inactivation of the sugar transports seems a consequence of the turnover of the sugar carriers whose apparent half-lives were 2 to 7 h.

EFFECTS OF VEGETABLE TANNINS ON GLUCOSE OXIDATION BY VARIOUS MICROORGANISMS

1966 ◽  
Vol 12 (4) ◽  
pp. 787-794 ◽  
Author(s):  
J. Basaraba
Keyword(s):  
Escherichia Coli ◽  
Saccharomyces Cerevisiae ◽  
Energy Source ◽  
Pseudomonas Fluorescens ◽  
Glucose Oxidation ◽  
Glucose Utilization ◽  
Resting Cells ◽  
E Coli ◽  
Vegetable Tannins ◽  
Chestnut Wood

The effects of purified tannin preparations of chestnut wood and of wattle bark on the respiration of resting cells of microorganisms were measured in a Warburg apparatus. Tannins were tested at 0.5% (w/v) concentration alone and in mixtures with glucose which provided energy for the microorganisms. In presence of the chestnut and wattle tannins, the exogenous respiration of Asotobacter vinelandii was reduced by 50 and 85% and that of Escherichia coli by 40 and 20%, respectively; respiration of Azatobacler chroococcum was completely inhibited by either tannin. Glucose oxidation by Rhizobium melioti, Rhisobium sp., and Saccharomyces cerevisiae was inhibited by tannins to small degrees. Tannins had no effect on glucose utilization by Rhodotorula sp. and Pseudomonas fluorescens. A. vinelandii, E. coli, and P. fluorescens utilized tannins, especially wattle, as an energy source.

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