Genetic and biochemical characterization of Saccharomyces cerevisiae mutants resistant to trifluoroleucine

Casalone, Enrico; Fia, Giovanna; Barberio, Claudia; Cavalieri, Duccio; Turbanti, Luca; Polsinelli, Mario

doi:10.1016/s0923-2508(97)88085-0

Cited by 24 publications

(35 citation statements)

References 22 publications

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“…Many genes in the branched-chain amino acid biosynthetic pathway are also overexpressed: BAT1 is overexpressed 3.9-fold, and other genes in the isoleucine-valine pathway are overexpressed by factors of about 2. Excess leucine is metabolized into products including isoamyl alcohol (18), a substance previously shown to induce filamentous growth in liquid culture (19).…”

Section: Resultsmentioning

confidence: 99%

Manifold anomalies in gene expression in a vineyard isolate of Saccharomyces cerevisiae revealed by DNA microarray analysis

Cavalieri

Townsend

Hartl

2000

Proc. Natl. Acad. Sci. U.S.A.

159

144

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Genome-wide transcriptional profiling has important applications in evolutionary biology for assaying the extent of heterozygosity for alleles showing quantitative variation in gene expression in natural populations. We have used DNA microarray analysis to study the global pattern of transcription in a homothallic strain of Saccharomyces cerevisiae isolated from wine grapes in a Tuscan vineyard, along with the diploid progeny obtained after sporulation. The parental strain shows 2:2 segregation (heterozygosity) for three unlinked loci. One determines resistance to trifluoroleucine; another, resistance to copper sulfate; and the third is associated with a morphological phenotype observed as colonies with a ridged surface resembling a filigree. Global expression analysis of the progeny with the filigreed and smooth colony phenotypes revealed a greater than 2-fold difference in transcription for 378 genes (6% of the genome). A large number of the overexpressed genes function in pathways of amino acid biosynthesis (particularly methionine) and sulfur or nitrogen assimilation, whereas many of the underexpressed genes are amino acid permeases. These wholesale changes in amino acid metabolism segregate as a suite of traits resulting from a single gene or a small number of genes. We conclude that natural vineyard populations of S. cerevisiae can harbor alleles that cause massive alterations in the global patterns of gene expression. Hence, studies of expression variation in natural populations, without accompanying segregation analysis, may give a false picture of the number of segregating genes underlying the variation.

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Section: Resultsmentioning

confidence: 99%

Manifold anomalies in gene expression in a vineyard isolate of Saccharomyces cerevisiae revealed by DNA microarray analysis

Cavalieri

Townsend

Hartl

2000

Proc. Natl. Acad. Sci. U.S.A.

159

144

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“…Screening for drug resistance such as TFL and cerulenin, which are an L-leucine analogue and a potent fatty acid synthetase (FAS) inhibitor, respectively, has been shown to be useful for isolating yeast strains with a high capacity to produce flavoring compounds (1,5,9,10,21,38). In TFL-resistant strains there is an increase in the production of higher alcohols and their esters, particularly isoamyl alcohol and isoamyl acetate, associated with a fruity and sweet aroma.…”

Section: Discussionmentioning

confidence: 99%

“…Previous studies have shown that LEU4 mutant strains yield an ␣-isopropylmalate synthase that is insensitive to feedback inhibition by leucine resistance to TFL. Such mutant strains are leucine overproducers and also produce higher amounts of isoamyl alcohol (1,9,10).…”

Section: Discussionmentioning

confidence: 99%

Biochemical and Molecular Characterization ofSaccharomyces cerevisiaeStrains Obtained from Sugar-Cane Juice Fermentations and Their Impact in Cachaça Production

Oliveira

Vicente

Fietto

et al. 2008

Appl Environ Microbiol

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Saccharomyces cerevisiae strains from different regions of Minas Gerais, Brazil, were isolated and characterized aiming at the selection of starter yeasts to be used in the production of cachaça, the Brazilian sugar cane spirit. The methodology established took into account the screening for biochemical traits desirable in a yeast cachaça producer, such as no H 2 S production, high tolerance to ethanol and high temperatures, high fermentative capacity, and the abilities to flocculate and to produce mycocins. Furthermore, the yeasts were exposed to drugs such as 5,5,5؆-trifluor-D,L-leucine and cerulenin to isolate those that potentially overproduce higher alcohols and esters. The utilization of a random amplified polymorphic DNA-PCR method with primers based on intron splicing sites flanking regions of the COX1 gene, as well as microsatellite analysis, was not sufficient to achieve good differentiation among selected strains. In contrast, karyotype analysis allowed a clear distinction among all strains. Two selected strains were experimentally evaluated as cachaça producers. The results suggest that the selection of strains as fermentation starters requires the combined use of biochemical and molecular criteria to ensure the isolation and identification of strains with potential characteristics to produce cachaça with a higher quality standard.Cachaça (pronounced "kha-sha-ssa"), the sugar cane spirit, is the most popular distilled beverage produced in Brazil. The annual production reaches 1.3 billion liters, with 15% being produced in more than 8,500 distilleries in the state of Minas Gerais.Traditional cachaça production relies on a spontaneous fermentative process that is mediated by the microbiota present in the cane juice wort and on the surface of equipments used in the productive process. It has been already demonstrated that in such systems there occurs a succession of yeasts, with Saccharomyces cerevisiae being the predominant species. Cachaça quality depends on the ecology of the microbial populations during an initial spontaneous fermentation (18,29,31,32,39). The fermentative process occurs through a continuously open fermentative process which is completed within 24 h and generally takes place from May to November, corresponding to the sugar cane harvesting period.Considering the conditions of production usually found in the cachaça distilleries, fermenting yeast populations have to face different types of stress (osmotic, high temperature, and high ethanol concentration). Besides, they might also present some characteristics such as a good fermentative power, no H 2 S production, killer activity, flocculation ability, and production of flavoring compounds. Taking all of these factors into account, we have developed a strategy to select yeast strains with appropriated characteristics to produce cachaça with potentially higher-quality standards (52). Parallel to the selection and development of S. cerevisiae strains toward ethanolic fermentations, molecular methods were developed and validated to study...

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“…Additionally, early stationary phase cells of yeast strain CMBSPV03 (grown on YPD) were plated at 10 7 cells on YNB plates (BD Difco) plus 2% glucose with 1 mM 5,5,5-trifluoro-leucine (TFL) and incubated at 30°C for 48 h 8 . Yeast colonies were isolated on a second plate and this TFL-mutant strain was called CMBSPV03TFL.…”

Section: Yeast and Wortmentioning

confidence: 99%

Characteristics of High Cell Density Fermentations with Different Lager Yeast Strains

Verbelen

Mulders

Saison

et al. 2008

Journal of the Institute of Brewing

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To improve the productivity of the beer fermentation process, several strategies can be adopted. One of these promising strategies could be the increase of suspended yeast cells in the reactor. Therefore, the fermentation characteristics of 11 lager yeast strains were studied in normal pitched worts (20 × 10 6 cells/ mL) (LD) and in worts with a four-fold higher pitching rate (HD). The fermentation rate was 2-4 times increased when high initial cell levels were used. The net yeast growth was somewhat similar between the LD and the HD fermentations, although the FAN uptake level was about 35% higher in the HD fermentations compared with LD. High viabilities were observed throughout the fermentations with high cell loadings. HD fermentations resulted in higher concentrations of all the measured fusel alcohols and higher maxima and residual concentrations of total diacetyl were observed. In contrast, higher levels of most of the esters were found at the normal pitching rate, although the results of isoamyl acetate were not significant. With the help of "Principal Component Analysis", it became clear that the cell density had an important influence on the flavour profile, but that yeast specific preferences could not be overlooked as they determined the sensitivity of the yeast to the application of higher cell densities.

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Genetic and biochemical characterization of Saccharomyces cerevisiae mutants resistant to trifluoroleucine

Cited by 24 publications

References 22 publications

Manifold anomalies in gene expression in a vineyard isolate of Saccharomyces cerevisiae revealed by DNA microarray analysis

Manifold anomalies in gene expression in a vineyard isolate of Saccharomyces cerevisiae revealed by DNA microarray analysis

Biochemical and Molecular Characterization ofSaccharomyces cerevisiaeStrains Obtained from Sugar-Cane Juice Fermentations and Their Impact in Cachaça Production

Characteristics of High Cell Density Fermentations with Different Lager Yeast Strains

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