Whole cells Saccharomyces cerevisiae

While in the presence of 2-oxoglutaric acid neither decarboxylation nor acyloin condensation had been observed, as expected from previously published results (75), we succeeded in the enzymatic conversion of the mono ethyl ester 3 to ethyl 4-oxobutanoate 4, using both whole yeast cells (Saccharomyces cerevisiae) and purified PDC. The oxo ester 4 served as substrate for a second reaction catalyzed by PDC. Formation of a new carbon-carbon bond was accomplished in the presence of pyruvic acid which acted as donor of a C2-unit. Thus, ethyl 4-hydroxy-5-oxohexanoate 5 was obtained for the first time as the result of an enzymatic acyloin condensation. Finally, traces of acid induced the lactonization of hydroxyester 5, indicating it as direct precursor of solerone 1 (Figure 1). 

It was tempting to base the study of membrane transport in eukaryotic cells on similar simple principles. For this purpose, as well as for molecular biology as a whole, the yeast Saccharomyces cerevisiae appeared to be the best suited organism. From early times on, this yeast has occupied a privileged place for mankind. Due to... 

Katz, M., Frejd, T., Hahn-Haegerdal, B. and Gorwa-Grauslund, M.F. (2003) Efficient anaerobic whole cell stereoselective bioreduction with recombinant Saccharomyces cerevisiae. Biotechnology and Bioengineering, 84 (5), 573-582. 

Engelking, H., Pfaller, R., Wich, G. and Weuster-Botz, D. (2006) Reaction engineering studies on /3-ketoester reductions with whole cells of recombinant Saccharomyces cerevisiae. Enzyme and Microbial Technology, 38, 536-544. 

The structure of mannose-rich polysaccharide core in GL4 is close to that of yeast mannan (from Saccharomyces cerevisiae), which was inactive for IL-6 induction in a human peripheral whole-blood cells test system. This fact suggests that not the mannose moieties but other components, such as the lipophilic moiety and/or phosphates, are important for the activity. The lipophilic products in HF-hydrolysate of GL4 were then analyzed. In addition to peaks corresponding to the known fatty acids (C16 0, C18 1), two other unknown ion peaks at m/z 330 and 356 were found by FAB-MS (data not shown). 

The same behavior has already been observed with whole dehydrated cells of Saccharomyces cerevisiae [11] or immobilized ADH in the gas phase [45]. It seems also that the cellular matrix increases the need for hydration to perform catalysis. 

This behaviour is in agreement with data obtained by Grizon [49], who observed a dependence of the ADH activity of whole dehydrated cells of Saccharomyces cerevisiae upon pH of the buffer. For practical application it seems also important to suspend cells at the optimal pH for the isolated enzyme. 

Figure 4.1 GC/MS analysis of methyl esters prepared from a whole cell lipid extract of the YEpOLEX-PDesat-TnD11Z-transformed ole1 strain of Saccharomyces cerevisiae (A) total ion spectrum of fatty acid methyl esters resolved by capillary GLC (B) mass spectrum of the degradation products of the DMDS adduct of Z11 -16 Me in A. The diagnostic m/z values of the DMDS adduct of Z11-16 Me are labeled. (Reproduced with permission from Knipple et al., 1998. 1998 by The National Academy of Sciences.)...

Jorg, G., Hemery, T., Bertau, M. Effects of cell-stress protectant glutathione on the whole-cell biotransformation of ethyl 2-chloro-acetoacetate with Saccharomyces cerevisiae. Biocatal. Biotransform. 2005, 23 9-17. 

As a whole, PolyPs in cells of eukaryotes are characterized by plural localization, depending on the cell age or environmental conditions. For example, cytochemical data on the localization of PolyPs in the cells of Saccharomyces cerevisiae are presented in Figure 5.2, according to Vofisek et al. (1982). Further studies of this problem may provide new data on the functions of these biopolymers. 

Calcium chromate has been shown to induce cytoplasmic petite mutations in mitochondria of Saccharomyces cerevisiae K Calcium chromate also dramatically depressed the content of the mitochondrial gene products cytochrome aa3 and cytochrome b, in whole yeast cells. Chromate ( 8 nM) was readily taken up by rat thymocytes and after 30 min 9% of the Cr was found in the mitochondria although 62% was found in the nuclei . Isolated rat thymus mitochondria and nuclei readily took up CrOj . After one hour incubation of Erlich ascites tumor cells with CrOj (380 /nuclear fraction and 12% was in the mitochondrial-microsomal fraction. Levels of chromium in rat liver mitochondria reached a plateau six hours after i.v. injection of chromate (0.02 mg/kg) and remained at that level through 5 days. Liver nuclear chromium levels in the same animals, although similar to mitochondrial levels at 6 h, reached a maximum at 12 h and steadily decreased after that time. Therefore the nuclear chromium levels were lower than the mitochondrial chromium levels at later times (24-120 h) after injection. The subcellular distribution of chromium in the liver of rats injected i.v. with chromate (0.56 mg/kg) was also found to be time dependent in another study. The distribution of chromium in rat liver mitochondria increased from 5% at 15 min to 21% at 72 h and also increased in the nuclear fraction from 22% at 15 min to 52% at 72 h. Incubation of isolated rat liver mitochondria with chromate (0.3-16.6 electron transport chain of the mitochondrial iner membrane. 

Cell-wall formation in Saccharomyces cerevisiae appears to be the result of two main patterns of deposition of wall material, viz., around the whole periphery of the non-budding cells and mainly at the tip of the daughter cell, or at the cross-wall that separates dividing cells. Synthesis and secretion of j3-D-glucan is unaffected by inhibition of RNA and protein synthesis. Growth of S. cerevisiae under conditions of phosphate limitations results in a decreased content of D-glucan and increased protein content as compared with control cells. 

Definition Insol. proteinaceous material residue after mechanical rupture of yeast cells of Saccharomyces cerevisiae and removal of whole cell walls by centrifugation and separation of sol. cellular materials... 

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