scholarly journals Improved use of a public good selects for the evolution of undifferentiated multicellularity

eLife ◽  
2013 ◽  
Vol 2 ◽  
Author(s):  
John H Koschwanez ◽  
Kevin R Foster ◽  
Andrew W Murray
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Experimental Evolution ◽  
Cell Separation ◽  
Rational Design ◽  
Single Cells ◽  
Evolutionary Strategies ◽  
Hexose Transporter ◽  
Yeast Saccharomyces Cerevisiae ◽  
Know How ◽  
Transporter Expression

We do not know how or why multicellularity evolved. We used the budding yeast, Saccharomyces cerevisiae, to ask whether nutrients that must be digested extracellularly select for the evolution of undifferentiated multicellularity. Because yeast use invertase to hydrolyze sucrose extracellularly and import the resulting monosaccharides, single cells cannot grow at low cell and sucrose concentrations. Three engineered strategies overcame this problem: forming multicellular clumps, importing sucrose before hydrolysis, and increasing invertase expression. We evolved populations in low sucrose to ask which strategy they would adopt. Of 12 successful clones, 11 formed multicellular clumps through incomplete cell separation, 10 increased invertase expression, none imported sucrose, and 11 increased hexose transporter expression, a strategy we had not engineered. Identifying causal mutations revealed genes and pathways, which frequently contributed to the evolved phenotype. Our study shows that combining rational design with experimental evolution can help evaluate hypotheses about evolutionary strategies.

scholarly journals Molecular Basis of Fructose Utilization by the Wine Yeast Saccharomyces cerevisiae: a Mutated HXT3 Allele Enhances Fructose Fermentation

2007 ◽  
Vol 73 (8) ◽  
pp. 2432-2439 ◽  
Author(s):  
Carole Guillaume ◽  
Pierre Delobel ◽  
Jean-Marie Sablayrolles ◽  
Bruno Blondin
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Molecular Basis ◽  
Alcoholic Fermentation ◽  
Wine Yeast ◽  
Glycolytic Flux ◽  
Hexose Transporter ◽  
Wine Yeasts ◽  
Yeast Saccharomyces Cerevisiae ◽  
High Fructose ◽  
Fructose Fermentation

ABSTRACT Fructose utilization by wine yeasts is critically important for the maintenance of a high fermentation rate at the end of alcoholic fermentation. A Saccharomyces cerevisiae wine yeast able to ferment grape must sugars to dryness was found to have a high fructose utilization capacity. We investigated the molecular basis of this enhanced fructose utilization capacity by studying the properties of several hexose transporter (HXT) genes. We found that this wine yeast harbored a mutated HXT3 allele. A functional analysis of this mutated allele was performed by examining expression in an hxt1-7Δ strain. Expression of the mutated allele alone was found to be sufficient for producing an increase in fructose utilization during fermentation similar to that observed in the commercial wine yeast. This work provides the first demonstration that the pattern of fructose utilization during wine fermentation can be altered by expression of a mutated hexose transporter in a wine yeast. We also found that the glycolytic flux could be increased by overexpression of the mutant transporter gene, with no effect on fructose utilization. Our data demonstrate that the Hxt3 hexose transporter plays a key role in determining the glucose/fructose utilization ratio during fermentation.

scholarly journals Evolution of simple multicellularity increases environmental complexity

2016 ◽  
Author(s):  
María Rebolleda-Gómez ◽  
William C. Ratcliff ◽  
Jonathon Fankhauser ◽  
Michael Travisano
Keyword(s):  
Fluid Dynamics ◽  
Saccharomyces Cerevisiae ◽  
Experimental Evolution ◽  
Single Cells ◽  
Environmental Complexity ◽  
Major Transitions ◽  
Rapid Diversification ◽  
Ecological Mechanisms ◽  
Major Transitions In Evolution ◽  
Maintenance Of Diversity

AbstractMulticellularity—the integration of previously autonomous cells into a new, more complex organism—is one of the major transitions in evolution. Multicellularity changed evolutionary possibilities and facilitated the evolution of increased complexity. Transitions to multicellularity are associated with rapid diversification and increased ecological opportunity but the potential mechanisms are not well understood. In this paper we explore the ecological mechanisms of multicellular diversification during experimental evolution of the brewer’s yeast, Saccharomyces cerevisiae. The evolution from single cells into multicellular clusters modifies the structure of the environment, changing the fluid dynamics and creating novel ecological opportunities. This study demonstrates that even in simple conditions, incipient multicellularity readily changes the environment, facilitating the origin and maintenance of diversity.

scholarly journals The GTS1 gene, which contains a Gly-Thr repeat, affects the timing of budding and cell size of the yeast Saccharomyces cerevisiae.

1994 ◽  
Vol 14 (8) ◽  
pp. 5569-5578 ◽  
Author(s):  
K Mitsui ◽  
S Yaguchi ◽  
K Tsurugi
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acid ◽  
Cell Size ◽  
Single Cells ◽  
Exponential Growth Phase ◽  
Restrictive Temperature ◽  
Multicopy Plasmid ◽  
Wild Type ◽  
Yeast Saccharomyces Cerevisiae ◽  
Mean Cell Volume

A gene with an open reading frame encoding a protein of 417 amino acid residues with a Gly-Thr repeat was isolated from the yeast Saccharomyces cerevisiae by using synthetic oligonucleotides encoding three Gly-Thr dimers as probes. The deduced amino acid sequence showed partial homology to the clock-affecting gene, per, of Drosophila melanogaster in the regions including the GT repeat. The function of the gene, named GTS1, was examined by characterizing the phenotypes of transformants with different copy numbers of the GTS1 gene produced either by inactivating the GTS1 gene by gene disruption (TM delta gts1) or by transformation with multicopy plasmid pPER119 (TMpGTS1). They grew at similar rates during the exponential growth phase, but the lag phases were shorter for TM delta gts1 and longer for TMpGTS1 cells than that for the wild type. Analyses of their cell cycle parameters using synchronized cells revealed that the unbudding period changed as a function of gene dosage; that is, the periods of TM delta gts1 and TMpGTS1 were about 20% shorter and longer, respectively, than that of the wild-type. Another significant change in the transformants was detected in the distribution of the cell size. The mean cell volume of the TM delta gts1 cells in the unbudded period (single cells) was 27% smaller than that of single wild-type cells, whereas that of single TMpGTS1 cells was 48% larger. Furthermore, in the temperature-sensitive cdc4 mutant, the GTS1 gene affected the timing of budding at the restrictive temperature. Thus, the GTS1 gene product appears to modulate the timing of budding to obtain an appropriate cell size independent of the DNA replication cycle.

scholarly journals Protein synthesis requirements for nuclear division, cytokinesis, and cell separation in Saccharomyces cerevisiae.

1991 ◽  
Vol 11 (7) ◽  
pp. 3691-3698 ◽  
Author(s):  
D J Burke ◽  
D Church
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Protein Synthesis ◽  
Cell Division ◽  
Cell Separation ◽  
Nuclear Division ◽  
S Phase ◽  
Protein Synthesis Inhibitors ◽  
Yeast Saccharomyces Cerevisiae ◽  
Chemical Inhibitors

Protein synthesis inhibitors have often been used to identify regulatory steps in cell division. We used cell division cycle mutants of the yeast Saccharomyces cerevisiae and two chemical inhibitors of translation to investigate the requirements for protein synthesis for completing landmark events after the G1 phase of the cell cycle. We show, using cdc2, cdc6, cdc7, cdc8, cdc17 (38 degrees C), and cdc21 (also named tmp1) mutants, that cells arrested in S phase complete DNA synthesis but cannot complete nuclear division if protein synthesis is inhibited. In contrast, we show, using cdc16, cdc17 (36 degrees C), cdc20, cdc23, and nocodazole treatment, that cells that arrest in the G2 stage complete nuclear division in the absence of protein synthesis. Protein synthesis is required late in the cell cycle to complete cytokinesis and cell separation. These studies show that there are requirements for protein synthesis in the cell cycle, after G1, that are restricted to two discrete intervals.

scholarly journals Oscillatory nucleocytoplasmic shuttling of the general stress response transcriptional activators Msn2 and Msn4 in Saccharomyces cerevisiae

2003 ◽  
Vol 161 (3) ◽  
pp. 497-505 ◽  
Author(s):  
Michel Jacquet ◽  
Georges Renault ◽  
Sylvie Lallet ◽  
Jan De Mey ◽  
Albert Goldbeter
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Single Cells ◽  
Time Lapse ◽  
Oscillatory Behavior ◽  
Transcriptional Activators ◽  
Nucleocytoplasmic Shuttling ◽  
Yeast Saccharomyces Cerevisiae ◽  
Nutritional Limitation ◽  
Response To Stress ◽  
General Response

Msn2 and Msn4 are two related transcriptional activators that mediate a general response to stress in yeast Saccharomyces cerevisiae by eliciting the expression of specific sets of genes. In response to stress or nutritional limitation, Msn2 and Msn4 migrate from the cytoplasm to the nucleus. Using GFP-tagged constructs and high-resolution time-lapse video microscopy on single cells, we show that light emitted by the microscope also triggers this migration. Unexpectedly, the population of Msn2 or Msn4 molecules shuttles repetitively into and out of the nucleus with a periodicity of a few minutes. A large heterogeneity in the oscillatory response to stress is observed between individual cells. This periodic behavior, which can be induced by various types of stress, at intermediate stress levels, is not dependent upon protein synthesis and persists when the DNA-binding domain of Msn2 is removed. The cAMP–PKA pathway controls the sensitivity of the oscillatory nucleocytoplasmic shuttling. In the absence of PKA, Msn4 continues to oscillate while Msn2 is maintained in the nucleus. We show that a computational model based on the possibility that Msn2 and Msn4 participate in autoregulatory loops controlling their subcellular localization can account for the oscillatory behavior of the two transcription factors.

scholarly journals Reduction of Ethanol Yield and Improvement of Glycerol Formation by Adaptive Evolution of the Wine Yeast Saccharomyces cerevisiae under Hyperosmotic Conditions

2014 ◽  
Vol 80 (8) ◽  
pp. 2623-2632 ◽  
Author(s):  
Valentin Tilloy ◽  
Anne Ortiz-Julien ◽  
Sylvie Dequin
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Adaptive Evolution ◽  
Rational Design ◽  
Ethanol Yield ◽  
Wine Yeast ◽  
Wine Industry ◽  
Carbon Limitation ◽  
Adaptive Laboratory Evolution ◽  
Yeast Saccharomyces Cerevisiae ◽  
Ancestral Strain

ABSTRACTThere is a strong demand from the wine industry for methodologies to reduce the alcohol content of wine without compromising wine's sensory characteristics. We assessed the potential of adaptive laboratory evolution strategies under hyperosmotic stress for generation ofSaccharomyces cerevisiaewine yeast strains with enhanced glycerol and reduced ethanol yields. Experimental evolution on KCl resulted, after 200 generations, in strains that had higher glycerol and lower ethanol production than the ancestral strain. This major metabolic shift was accompanied by reduced fermentative capacities, suggesting a trade-off between high glycerol production and fermentation rate. Several evolved strains retaining good fermentation performance were selected. These strains produced more succinate and 2,3-butanediol than the ancestral strain and did not accumulate undesirable organoleptic compounds, such as acetate, acetaldehyde, or acetoin. They survived better under osmotic stress and glucose starvation conditions than the ancestral strain, suggesting that the forces that drove the redirection of carbon fluxes involved a combination of osmotic and salt stresses and carbon limitation. To further decrease the ethanol yield, a breeding strategy was used, generating intrastrain hybrids that produced more glycerol than the evolved strain. Pilot-scale fermentation on Syrah using evolved and hybrid strains produced wine with 0.6% (vol/vol) and 1.3% (vol/vol) less ethanol, more glycerol and 2,3-butanediol, and less acetate than the ancestral strain. This work demonstrates that the combination of adaptive evolution and breeding is a valuable alternative to rational design for remodeling the yeast metabolic network.

Protein synthesis requirements for nuclear division, cytokinesis, and cell separation in Saccharomyces cerevisiae

1991 ◽  
Vol 11 (7) ◽  
pp. 3691-3698
Author(s):  
D J Burke ◽  
D Church
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Protein Synthesis ◽  
Cell Division ◽  
Cell Separation ◽  
Nuclear Division ◽  
S Phase ◽  
Protein Synthesis Inhibitors ◽  
Yeast Saccharomyces Cerevisiae ◽  
Chemical Inhibitors

Protein synthesis inhibitors have often been used to identify regulatory steps in cell division. We used cell division cycle mutants of the yeast Saccharomyces cerevisiae and two chemical inhibitors of translation to investigate the requirements for protein synthesis for completing landmark events after the G1 phase of the cell cycle. We show, using cdc2, cdc6, cdc7, cdc8, cdc17 (38 degrees C), and cdc21 (also named tmp1) mutants, that cells arrested in S phase complete DNA synthesis but cannot complete nuclear division if protein synthesis is inhibited. In contrast, we show, using cdc16, cdc17 (36 degrees C), cdc20, cdc23, and nocodazole treatment, that cells that arrest in the G2 stage complete nuclear division in the absence of protein synthesis. Protein synthesis is required late in the cell cycle to complete cytokinesis and cell separation. These studies show that there are requirements for protein synthesis in the cell cycle, after G1, that are restricted to two discrete intervals.

scholarly journals The GTS1 gene, which contains a Gly-Thr repeat, affects the timing of budding and cell size of the yeast Saccharomyces cerevisiae

1994 ◽  
Vol 14 (8) ◽  
pp. 5569-5578
Author(s):  
K Mitsui ◽  
S Yaguchi ◽  
K Tsurugi
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acid ◽  
Cell Size ◽  
Single Cells ◽  
Exponential Growth Phase ◽  
Restrictive Temperature ◽  
Multicopy Plasmid ◽  
Wild Type ◽  
Yeast Saccharomyces Cerevisiae ◽  
Mean Cell Volume

A gene with an open reading frame encoding a protein of 417 amino acid residues with a Gly-Thr repeat was isolated from the yeast Saccharomyces cerevisiae by using synthetic oligonucleotides encoding three Gly-Thr dimers as probes. The deduced amino acid sequence showed partial homology to the clock-affecting gene, per, of Drosophila melanogaster in the regions including the GT repeat. The function of the gene, named GTS1, was examined by characterizing the phenotypes of transformants with different copy numbers of the GTS1 gene produced either by inactivating the GTS1 gene by gene disruption (TM delta gts1) or by transformation with multicopy plasmid pPER119 (TMpGTS1). They grew at similar rates during the exponential growth phase, but the lag phases were shorter for TM delta gts1 and longer for TMpGTS1 cells than that for the wild type. Analyses of their cell cycle parameters using synchronized cells revealed that the unbudding period changed as a function of gene dosage; that is, the periods of TM delta gts1 and TMpGTS1 were about 20% shorter and longer, respectively, than that of the wild-type. Another significant change in the transformants was detected in the distribution of the cell size. The mean cell volume of the TM delta gts1 cells in the unbudded period (single cells) was 27% smaller than that of single wild-type cells, whereas that of single TMpGTS1 cells was 48% larger. Furthermore, in the temperature-sensitive cdc4 mutant, the GTS1 gene affected the timing of budding at the restrictive temperature. Thus, the GTS1 gene product appears to modulate the timing of budding to obtain an appropriate cell size independent of the DNA replication cycle.

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