Saccharomyces cerevisiae activity

The content of ergosterol in the species and strains of yeast Saccharomyces cerevisiae (active dried yeast, a type of yeast used to make dough rise in baking) varies within wide limits from 600 to 1500 p-g/kg (drymatter). 

Wang et al.2 and Najafpour et al.3A worked with immobilised microbial cells of Nitrobacer agilis, Saccharomyces cerevisiae and Pseudomonas aeruginosa in gel beads, respectively. They found separately that the cells retained more than 90% of their activity after immobilisation by using specific oxygen uptake rate (SOUR) [mg 02g 1 (dry biomass) h 11 as the biomass activity indicator. Such differences in immobilised biomass and activity between free and immobilised biomass activities depend strongly on the particular characteristics of the microbial systems and their interaction with the support matrix. 

In the reduction of racemic /i-ketosulphoxides (e.g. 464a) with actively fermenting yeast (Saccharomyces cerevisiae) the enantiomers are reduced at sufficiently different rates to allow isolation of optically active /1-hydroxy sulphoxide 524 and unreacted optically active /1-ketosulphoxide with at least 95% optical purity617,618 (equation 323). 

Endosulfan is toxic to yeast but is also mutagenic without activation (Yadav et al. 1982). In vitro, endosulfan induced reverse mutations and mitotic gene conversion and increased the percentage of aberrant colonies in Saccharomyces cerevisiae but did not induce mitotic cross-overs (Yadav et al. 1982). 

In current industrial practice, benzaldehyde is added to fermenting baker s yeast Saccharomyces cerevisiae) with resultant PAC production occurring from the yeast-derived pyruvate. Typically PAC concentrations of 12-15 g F are produced at yields of 65-70% theoretical in a 10-12 h biotransformation process. [2], Appreciable concentrations of benzyl alcohol are produced as by-product due to oxidoreductase activity in the fermentative yeast. 

Callen DF, Wolf CR, Philpot RM. 1980. Cytochrome P-450-mediated genetic activity and cytotoxicity of seven halogenated aliphatic hydrocarbons in Saccharomyces cerevisiae. Mutat Res 77 55-63. 

Yeasts contain a large number of different active and passive sugar-transport systems. The first of these to be cloned was the glucose-repressible, high-affinity passive glucose transporter of Saccharomyces cerevisiae, which is encoded by the SNF3 gene... 

Feedback inhibition of amino acid transporters by amino acids synthesized by the cells might be responsible for the well known fact that blocking protein synthesis by cycloheximide in Saccharomyces cerevisiae inhibits the uptake of most amino acids [56]. Indeed, under these conditions, endogenous amino acids continue to accumulate. This situation, which precludes studying amino acid transport in yeast in the presence of inhibitors of protein synthesis, is very different from that observed in bacteria, where amino acid uptake is commonly measured in the presence of chloramphenicol in order to isolate the uptake process from further metabolism of accumulated substances. In yeast, when nitrogen starvation rather than cycloheximide is used to block protein synthesis, this leads to very high uptake activity. This fact supports the feedback inhibition interpretation of the observed cycloheximide effect. 

King DJ, MR Azari, A Wiseman (1984) Studies on the properties of highly purified cytochrome P-448 and its dependent activity benzo[a]pyrene hydroxylase, from Saccharomyces cerevisiae. Xenobiotica 14 187-206. 

A cytochrome P450 has been purified from Saccharomyces cerevisiae that has benzo[a]pyrene hydroxylase activity (King et al. 1984), and metabolizes benzo[fl]pyrene to 3- and 9-hydroxybenzo[fl]pyrene and benzo[fl]pyrene-7,8-dihydrodiol (Wiseman and Woods 1979). The transformation of PAHs by Candida Upolytica produced predominantly monohydroxyl-ated products naphth-l-ol from naphthalene, 4-hydroxybiphenyl from biphenyl and 3- and 9-hydroxybenzo[fl]pyrene from benzo[fl]pyrene (Cerniglia and Crow 1981). The transformation of phenanthrene was demonstrated in a number of yeasts isolated from littoral sediments and of these, Trichosporumpenicillatum was the most active. In contrast, biotransformation of benz[fl]anthracene by Candida krusei and Rhodotorula minuta was much slower (MacGillivray and Shiaris 1993). 

The mutagenic potential of diisopropyl methylphosphonate was investigated using the Ames assay. The compound was obtained from two different sources and tested on Salmonella typhimurium strains TA-1535, TA-1537, TA-1538, TA-98, and TA-100, both with and without S-9 activation. The compound did not demonstrate mutagenic activity in any of the assays (Hart 1980). Diisopropyl methylphosphonate was also negative for gene mutation in Saccharomyces cerevisiae (Hart 1980). 

Co-for-Zn substitution in alcohol dehydrogenase from Saccharomyces cerevisiae revealed a 100-fold increase in activity and a higher resistance of the modified protein to the inhibitory action of other divalent transition metals,1208 making the Co-modified enzyme suitable for biotechnological applications. 

Simmon VF. 1979a. In vitro assays for recombinogenic activity of chemical carcinogens and related compounds with Saccharomyces cerevisiae D3. J Nat Cancer Inst 62 901-909. 

Hasslacher, M., Schall, M., Hayn, M. et al. (1996) Molecular cloning of the full-length cDNA of (5)-hydroxynitrile lyase from Hevea brasiliensis. Functional expression in Escherichia coli and Saccharomyces cerevisiae and identification of an active site residue. The Journal of Biological Chemistry, 271, 5884-5891. 

BS, Bacillus subtilis CA, Candida albicans SA, Staphylococcus aureus SC, Saccharomyces cerevisiae TM, Trichophyton mentagrophytes PN, Penicillium nonatum KB, LOVO (colon cancer), P388 are cell lines in cytotoxic activity testings. 

Ramalho PA, Paiva S, Cavaco-Paulo A et al (2005) Azo reductase activity of intact Saccharomyces cerevisiae cells is dependent on the Frelp component of plasma membrane ferric reductase. Appl Environ Microbiol 71 3882-3888... 

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