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Mooiman C, Bouwknegt J, Dekker WJC, Wiersma SJ, Ortiz-Merino RA, de Hulster E, Pronk JT. Critical parameters and procedures for anaerobic cultivation of yeasts in bioreactors and anaerobic chambers. FEMS Yeast Res 2021; 21:foab035. [PMID: 34100921 PMCID: PMC8216787 DOI: 10.1093/femsyr/foab035] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 06/06/2021] [Indexed: 12/11/2022] Open
Abstract
All known facultatively fermentative yeasts require molecular oxygen for growth. Only in a small number of yeast species, these requirements can be circumvented by supplementation of known anaerobic growth factors such as nicotinate, sterols and unsaturated fatty acids. Biosynthetic oxygen requirements of yeasts are typically small and, unless extensive precautions are taken to minimize inadvertent entry of trace amounts of oxygen, easily go unnoticed in small-scale laboratory cultivation systems. This paper discusses critical points in the design of anaerobic yeast cultivation experiments in anaerobic chambers and laboratory bioreactors. Serial transfer or continuous cultivation to dilute growth factors present in anaerobically pre-grown inocula, systematic inclusion of control strains and minimizing the impact of oxygen diffusion through tubing are identified as key elements in experimental design. Basic protocols are presented for anaerobic-chamber and bioreactor experiments.
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Affiliation(s)
- Christiaan Mooiman
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Jonna Bouwknegt
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Wijb J C Dekker
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Sanne J Wiersma
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Raúl A Ortiz-Merino
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Erik de Hulster
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Jack T Pronk
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
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2
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Chen H, Blum JE, Thalacker-Mercer A, Gu Z. Impact of the Whole Genome Duplication Event on PYK Activity and Effects of a PYK1 Mutation on Metabolism in S. cerevisiae. Front Mol Biosci 2021; 8:656461. [PMID: 33796550 PMCID: PMC8007964 DOI: 10.3389/fmolb.2021.656461] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 02/22/2021] [Indexed: 11/13/2022] Open
Abstract
Background: Evolution of aerobic fermentation (crabtree effect) in yeast is associated with the whole genome duplication (WGD) event, suggesting that duplication of certain genes may have altered yeast metabolism. The pyruvate kinase (PYK) gene is associated with alterations in cell metabolism, and duplicated during the WGD, generating PYK1 and PYK2. Thus, the impact of WGD on PYK activity and role of PYK in yeast metabolism were explored. Methods: PYK activity in the presence or absence of fructose-1,6-bisphosphate (FBP) was compared between pre- and post-WGD yeast. Glucose consumption, ethanol production, and oxygen consumption were measured in wildtype yeast and yeast with a T403E point mutation, which alters FBP binding affinity. Results: FBP stimulated increased PYK activity in pre-WGD yeast and in the PYK1 isoforms of post-WGD yeast, but not in the PYK2 isoforms of post-WGD yeast. Compared to wildtype, T403E mutant yeast displayed reduced glucose consumption, reduced ethanol production, and increased mitochondrial metabolism. Conclusion: The WGD event impacted the sensitivity of PYK activity to FBP. Mutations in the FBP binding domain of PYK induce metabolic shifts that favor respiration and suppress fermentation.
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Affiliation(s)
- Hong Chen
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, United States
| | - Jamie E Blum
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, United States
| | - Anna Thalacker-Mercer
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, United States.,Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Zhenglong Gu
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, United States
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3
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Reconstruction and analysis of genome-scale metabolic model of weak Crabtree positive yeast Lachancea kluyveri. Sci Rep 2020; 10:16314. [PMID: 33004914 PMCID: PMC7530994 DOI: 10.1038/s41598-020-73253-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 09/04/2020] [Indexed: 01/15/2023] Open
Abstract
Lachancea kluyveri, a weak Crabtree positive yeast, has been extensively studied for its unique URC pyrimidine catabolism pathway. It produces more biomass than Saccharomyces cerevisiae due to the underlying weak Crabtree effect and resorts to fermentation only in oxygen limiting conditions that renders it as a suitable industrial host. The yeast also produces ethyl acetate as a major overflow metabolite in aerobic conditions. Here, we report the first genome-scale metabolic model, iPN730, of L. kluyveri comprising of 1235 reactions, 1179 metabolites, and 730 genes distributed in 8 compartments. The in silico viability in different media conditions and the growth characteristics in various carbon sources show good agreement with experimental data. Dynamic flux balance analysis describes the growth dynamics, substrate utilization and product formation kinetics in various oxygen-limited conditions. We have also demonstrated the effect of switching carbon sources on the production of ethyl acetate under varying oxygen uptake rates. A phenotypic phase plane analysis described the energetic cost penalty of ethyl acetate and ethanol production on the specific growth rate of L. kluyveri. We generated the context specific models of L. kluyveri growing on uracil or ammonium salts as the sole nitrogen source. Differential flux calculated using flux variability analysis helped us in highlighting pathways like purine, histidine, riboflavin and pyrimidine metabolism associated with uracil degradation. The genome-scale metabolic construction of L. kluyveri will provide a better understanding of metabolism behind ethyl acetate production as well as uracil catabolism (pyrimidine degradation) pathway. iPN730 is an addition to genome-scale metabolic models of non-conventional yeasts that will facilitate system-wide omics analysis to understand fungal metabolic diversity.
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Escalera-Fanjul X, Quezada H, Riego-Ruiz L, González A. Whole-Genome Duplication and Yeast’s Fruitful Way of Life. Trends Genet 2019; 35:42-54. [DOI: 10.1016/j.tig.2018.09.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 08/10/2018] [Accepted: 09/27/2018] [Indexed: 01/30/2023]
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5
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Campero‐Basaldua C, Quezada H, Riego‐Ruíz L, Márquez D, Rojas E, González J, El‐Hafidi M, González A. Diversification of the kinetic properties of yeast NADP-glutamate-dehydrogenase isozymes proceeds independently of their evolutionary origin. Microbiologyopen 2017; 6:e00419. [PMID: 27864882 PMCID: PMC5387307 DOI: 10.1002/mbo3.419] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 09/23/2016] [Accepted: 09/28/2016] [Indexed: 02/02/2023] Open
Abstract
In the yeast Saccharomyces cerevisiae, the ScGDH1 and ScGDH3 encoded glutamate dehydrogenases (NADP-GDHs) catalyze the synthesis of glutamate from ammonium and α-ketoglutarate (α-KG). Previous kinetic characterization showed that these enzymes displayed different allosteric properties and respectively high or low rate of α-KG utilization. Accordingly, the coordinated action of ScGdh1 and ScGdh3, regulated balanced α-KG utilization for glutamate biosynthesis under either fermentative or respiratory conditions, safeguarding energy provision. Here, we have addressed the question of whether there is a correlation between the regulation and kinetic properties of the NADP-GDH isozymes present in S. cerevisiae (ScGdh1 and ScGdh3), Kluyveromyces lactis (KlGdh1), and Lachancea kluyveri (LkGdh1) and their evolutionary history. Our results show that the kinetic properties of K. lactis and L. kluyveri single NADP-GDHs are respectively similar to either ScGDH3 or ScGDH1, which arose from the whole genome duplication event of the S. cerevisiae lineage, although, KlGDH1 and LkGDH1 originated from a GDH clade, through an ancient interspecies hybridization event that preceded the divergence between the Saccharomyces clade and the one containing the genera Kluyveromyces, Lachancea, and Eremothecium. Thus, the kinetic properties which determine the NADP-GDHs capacity to utilize α-KG and synthesize glutamate do not correlate with their evolutionary origin.
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Affiliation(s)
- Carlos Campero‐Basaldua
- Departamento de Bioquímica y Biología EstructuralInstituto de Fisiología CelularUniversidad Nacional Autónoma de MéxicoMexico CityMéxico
| | - Héctor Quezada
- Laboratorio de Inmunología y ProteómicaHospital Infantil de México Federico GómezMexico CityMéxico
| | | | - Dariel Márquez
- Departamento de Bioquímica y Biología EstructuralInstituto de Fisiología CelularUniversidad Nacional Autónoma de MéxicoMexico CityMéxico
| | - Erendira Rojas
- Departamento de Bioquímica y Biología EstructuralInstituto de Fisiología CelularUniversidad Nacional Autónoma de MéxicoMexico CityMéxico
| | - James González
- Departamento de Bioquímica y Biología EstructuralInstituto de Fisiología CelularUniversidad Nacional Autónoma de MéxicoMexico CityMéxico
| | - Mohammed El‐Hafidi
- Departamento de Biomedicina CardiovascularInstituto Nacional de Cardiología Ignacio ChávezMexico CityMéxico
| | - Alicia González
- Departamento de Bioquímica y Biología EstructuralInstituto de Fisiología CelularUniversidad Nacional Autónoma de MéxicoMexico CityMéxico
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6
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Boakye-Boaten NA, Xiu S, Shahbazi A, Wang L, Li R, Schimmel K. Uses of miscanthus press juice within a green biorefinery platform. BIORESOURCE TECHNOLOGY 2016; 207:285-292. [PMID: 26896712 DOI: 10.1016/j.biortech.2016.02.030] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 02/03/2016] [Accepted: 02/04/2016] [Indexed: 06/05/2023]
Abstract
This study assesses some uses of nutrient-rich juice mechanically extracted from freshly harvested Miscanthus x giganteus (MxG) as part of a green biorefinery system. The juice was used for culturing Saccharomyces cerevisiae and lactic acid bacteria. MxG juice was further used as substrate for fermentation to produce lactic acid using Lactobacillus brevis and Lactobacillus plantarum. The results show that MxG juice was a highly nutritious source for the cultivation of bacteria. Higher concentrations of MxG juice used as culture media, resulted in higher cell growth both aerobically and anaerobically. The highest ethanol yield of 70% theoretical and concentration of 0.75g/100ml were obtained from S. cerevisiae cultivated with 90% (v/v) MxG juice media and used for miscanthus solid fraction fermentation. 11.91g/L of lactic acid was also successfully produced from MxG juice through SSF.
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Affiliation(s)
- Nana Abayie Boakye-Boaten
- Energy and Environmental Systems Program, College of Arts and Science, North Carolina A & T State University, 1601 East Market Street, Greensboro, NC 27411, United States; Biological Engineering Program, Department of Natural Resources and Environmental Design, North Carolina A & T State University, 1601 East Market Street, Greensboro, NC 27411, United States
| | - Shuangning Xiu
- Biological Engineering Program, Department of Natural Resources and Environmental Design, North Carolina A & T State University, 1601 East Market Street, Greensboro, NC 27411, United States.
| | - Abolghasem Shahbazi
- Biological Engineering Program, Department of Natural Resources and Environmental Design, North Carolina A & T State University, 1601 East Market Street, Greensboro, NC 27411, United States
| | - Lijun Wang
- Biological Engineering Program, Department of Natural Resources and Environmental Design, North Carolina A & T State University, 1601 East Market Street, Greensboro, NC 27411, United States
| | - Rui Li
- Joint School of Nanoscience and Nanoengineering, North Carolina A & T State University, 2907 E. Gate City Blvd, Greensboro, NC 27401, United States; Biological Engineering Program, Department of Natural Resources and Environmental Design, North Carolina A & T State University, 1601 East Market Street, Greensboro, NC 27411, United States
| | - Keith Schimmel
- Energy and Environmental Systems Program, College of Arts and Science, North Carolina A & T State University, 1601 East Market Street, Greensboro, NC 27411, United States
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7
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Day M. Yeast petites and small colony variants: for everything there is a season. ADVANCES IN APPLIED MICROBIOLOGY 2016; 85:1-41. [PMID: 23942147 DOI: 10.1016/b978-0-12-407672-3.00001-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The yeast petite mutant was first found in the yeast Saccharomyces cerevisiae. The colony is small because of a block in the aerobic respiratory chain pathway, which generates ATP. The petite yeasts are thus unable to grow on nonfermentable carbon sources (such as glycerol or ethanol), and form small anaerobic-sized colonies when grown in the presence of fermentable carbon sources (such as glucose). The petite phenotype results from mutations in the mitochondrial genome, loss of mitochondria, or mutations in the host cell genome. The latter mutations affect nuclear-encoded genes involved in oxidative phosphorylation and these mutants are termed neutral petites. They all produce wild-type progeny when crossed with a wild-type strain. The staphylococcal small colony variant (SCV) is a slow-growing mutant that typically exhibits the loss of many phenotypic characteristics and pathogenic traits. SCVs are mostly small, nonpigmented, and nonhaemolytic. Their small size is often due to an inability to synthesize electron transport chain components and so cannot generate ATP by oxidative phosphorylation. Evidence suggests that they are responsible for persistent and/or recurrent infections. This chapter compares the physiological and genetic basis of the petite mutants and SCVs. The review focuses principally on two representatives, the eukaryote S. cerevisiae and the prokaryote Staphylococcus aureus. There is, clearly, commonality in the physiological response. Interestingly, the similarity, based on their physiological states, has not been commented on previously. The finding of an overlapping physiological response that occurs across a taxonomic divide is novel.
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Affiliation(s)
- Martin Day
- School of Biosciences, Cardiff University, Cardiff, United Kingdom.
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8
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Hagman A, Piškur J. A study on the fundamental mechanism and the evolutionary driving forces behind aerobic fermentation in yeast. PLoS One 2015; 10:e0116942. [PMID: 25617754 PMCID: PMC4305316 DOI: 10.1371/journal.pone.0116942] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Accepted: 12/16/2014] [Indexed: 02/03/2023] Open
Abstract
Baker’s yeast Saccharomyces cerevisiae rapidly converts sugars to ethanol and carbon dioxide at both anaerobic and aerobic conditions. The later phenomenon is called Crabtree effect and has been described in two forms, long-term and short-term effect. We have previously studied under fully controlled aerobic conditions forty yeast species for their central carbon metabolism and the presence of long-term Crabtree effect. We have also studied ten steady-state yeast cultures, pulsed them with glucose, and followed the central carbon metabolism and the appearance of ethanol at dynamic conditions. In this paper we analyzed those wet laboratory data to elucidate possible mechanisms that determine the fate of glucose in different yeast species that cover approximately 250 million years of evolutionary history. We determine overflow metabolism to be the fundamental mechanism behind both long- and short-term Crabtree effect, which originated approximately 125–150 million years ago in the Saccharomyces lineage. The “invention” of overflow metabolism was the first step in the evolution of aerobic fermentation in yeast. It provides a general strategy to increase energy production rates, which we show is positively correlated to growth. The “invention” of overflow has also simultaneously enabled rapid glucose consumption in yeast, which is a trait that could have been selected for, to “starve” competitors in nature. We also show that glucose repression of respiration is confined mainly among S. cerevisiae and closely related species that diverged after the whole genome duplication event, less than 100 million years ago. Thus, glucose repression of respiration was apparently “invented” as a second step to further increase overflow and ethanol production, to inhibit growth of other microbes. The driving force behind the initial evolutionary steps was most likely competition with other microbes to faster consume and convert sugar into biomass, in niches that were semi-anaerobic.
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Affiliation(s)
- Arne Hagman
- Department of Biology, Lund University, Lund, Sweden
- * E-mail:
| | - Jure Piškur
- Department of Biology, Lund University, Lund, Sweden
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9
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Dias O, Pereira R, Gombert AK, Ferreira EC, Rocha I. iOD907, the first genome-scale metabolic model for the milk yeastKluyveromyces lactis. Biotechnol J 2014; 9:776-90. [DOI: 10.1002/biot.201300242] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 04/07/2014] [Accepted: 04/23/2014] [Indexed: 11/08/2022]
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10
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Fuzi SFZM, Razali F, Jahim JM, Rahman RA, Illias RM. Simplified feeding strategies for the fed-batch cultivation of Kluyveromyces lactis GG799 for enhanced recombinant xylanase production. Bioprocess Biosyst Eng 2014; 37:1887-98. [DOI: 10.1007/s00449-014-1163-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Accepted: 02/26/2014] [Indexed: 12/19/2022]
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11
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Jasmin JN, Zeyl C. RAPID EVOLUTION OF CHEATING MITOCHONDRIAL GENOMES IN SMALL YEAST POPULATIONS. Evolution 2013; 68:269-75. [DOI: 10.1111/evo.12228] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Accepted: 07/30/2013] [Indexed: 01/05/2023]
Affiliation(s)
- Jean-Nicolas Jasmin
- Department of Biology; Wake Forest University; Winston-Salem North Carolina 27109
| | - Clifford Zeyl
- Department of Biology; Wake Forest University; Winston-Salem North Carolina 27109
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12
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Hagman A, Säll T, Compagno C, Piskur J. Yeast "make-accumulate-consume" life strategy evolved as a multi-step process that predates the whole genome duplication. PLoS One 2013; 8:e68734. [PMID: 23869229 PMCID: PMC3711898 DOI: 10.1371/journal.pone.0068734] [Citation(s) in RCA: 130] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2013] [Accepted: 06/03/2013] [Indexed: 11/19/2022] Open
Abstract
When fruits ripen, microbial communities start a fierce competition for the freely available fruit sugars. Three yeast lineages, including baker’s yeast Saccharomyces cerevisiae, have independently developed the metabolic activity to convert simple sugars into ethanol even under fully aerobic conditions. This fermentation capacity, named Crabtree effect, reduces the cell-biomass production but provides in nature a tool to out-compete other microorganisms. Here, we analyzed over forty Saccharomycetaceae yeasts, covering over 200 million years of the evolutionary history, for their carbon metabolism. The experiments were done under strictly controlled and uniform conditions, which has not been done before. We show that the origin of Crabtree effect in Saccharomycetaceae predates the whole genome duplication and became a settled metabolic trait after the split of the S. cerevisiae and Kluyveromyces lineages, and coincided with the origin of modern fruit bearing plants. Our results suggest that ethanol fermentation evolved progressively, involving several successive molecular events that have gradually remodeled the yeast carbon metabolism. While some of the final evolutionary events, like gene duplications of glucose transporters and glycolytic enzymes, have been deduced, the earliest molecular events initiating Crabtree effect are still to be determined.
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Affiliation(s)
- Arne Hagman
- Department of Biology, Molecular Cell Biology, Lund University, Lund, Sweden.
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13
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Mitochondrial genome evolution in a single protoploid yeast species. G3-GENES GENOMES GENETICS 2012; 2:1103-11. [PMID: 22973548 PMCID: PMC3429925 DOI: 10.1534/g3.112.003152] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Accepted: 07/09/2012] [Indexed: 12/26/2022]
Abstract
Mitochondria are organelles, which play a key role in some essential functions, including respiration, metabolite biosynthesis, ion homeostasis, and apoptosis. The vast numbers of mitochondrial DNA (mtDNA) sequences of various yeast species, which have recently been published, have also helped to elucidate the structural diversity of these genomes. Although a large corpus of data are now available on the diversity of yeast species, little is known so far about the mtDNA diversity in single yeast species. To study the genetic variations occurring in the mtDNA of wild yeast isolates, we performed a genome-wide polymorphism survey on the mtDNA of 18 Lachancea kluyveri (formerly Saccharomyces kluyveri) strains. We determined the complete mt genome sequences of strains isolated from various geographical locations (in North America, Asia, and Europe) and ecological niches (Drosophila, tree exudates, soil). The mt genome of the NCYC 543 reference strain is 51,525 bp long. It contains the same core of genes as Lachancea thermotolerans, the nearest relative to L. kluyveri. To explore the mt genome variations in a single yeast species, we compared the mtDNAs of the 18 isolates. The phylogeny and population structure of L. kluyveri provide clear-cut evidence for the existence of well-defined geographically isolated lineages. Although these genomes are completely syntenic, their size and the intron content were found to vary among the isolates studied. These genomes are highly polymorphic, showing an average diversity of 28.5 SNPs/kb and 6.6 indels/kb. Analysis of the SNP and indel patterns showed the existence of a particularly high overall level of polymorphism in the intergenic regions. The dN/dS ratios obtained are consistent with purifying selection in all these genes, with the noteworthy exception of the VAR1 gene, which gave a very high ratio. These data suggest that the intergenic regions have evolved very fast in yeast mitochondrial genomes.
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Sicard D, Legras JL. Bread, beer and wine: yeast domestication in the Saccharomyces sensu stricto complex. C R Biol 2011; 334:229-36. [PMID: 21377618 DOI: 10.1016/j.crvi.2010.12.016] [Citation(s) in RCA: 174] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Yeasts of the Saccharomyces sensu stricto species complex are able to convert sugar into ethanol and CO(2) via fermentation. They have been used for thousands years by mankind for fermenting food and beverages. In the Neolithic times, fermentations were probably initiated by naturally occurring yeasts, and it is unknown when humans started to consciously add selected yeast to make beer, wine or bread. Interestingly, such human activities gave rise to the creation of new species in the Saccharomyces sensu stricto complex by interspecies hybridization or polyploidization. Within the S. cerevisiae species, they have led to the differentiation of genetically distinct groups according to the food process origin. Although the evolutionary history of wine yeast populations has been well described, the histories of other domesticated yeasts need further investigation.
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Affiliation(s)
- Delphine Sicard
- Université Paris-Sud, UMR 0320/UMR 8120 Génétique Végétale, Gif-sur-Yvette, France.
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15
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Fang ZA, Wang GH, Chen AL, Li YF, Liu JP, Li YY, Bolotin-Fukuhara M, Bao WG. Gene responses to oxygen availability in Kluyveromyces lactis: an insight on the evolution of the oxygen-responding system in yeast. PLoS One 2009; 4:e7561. [PMID: 19855843 PMCID: PMC2763219 DOI: 10.1371/journal.pone.0007561] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2009] [Accepted: 09/16/2009] [Indexed: 11/18/2022] Open
Abstract
The whole-genome duplication (WGD) may provide a basis for the emergence of the very characteristic life style of Saccharomyces cerevisiae—its fermentation-oriented physiology and its capacity of growing in anaerobiosis. Indeed, we found an over-representation of oxygen-responding genes in the ohnologs of S. cerevisiae. Many of these duplicated genes are present as aerobic/hypoxic(anaerobic) pairs and form a specialized system responding to changing oxygen availability. HYP2/ANB1 and COX5A/COX5B are such gene pairs, and their unique orthologs in the ‘non-WGD’ Kluyveromyces lactis genome behaved like the aerobic versions of S. cerevisiae. ROX1 encodes a major oxygen-responding regulator in S. cerevisiae. The synteny, structural features and molecular function of putative KlROX1 were shown to be different from that of ROX1. The transition from the K. lactis-type ROX1 to the S. cerevisiae-type ROX1 could link up with the development of anaerobes in the yeast evolution. Bioinformatics and stochastic analyses of the Rox1p-binding site (YYYATTGTTCTC) in the upstream sequences of the S. cerevisiae Rox1p-mediated genes and of the K. lactis orthologs also indicated that K. lactis lacks the specific gene system responding to oxygen limiting environment, which is present in the ‘post-WGD’ genome of S. cerevisiae. These data suggested that the oxygen-responding system was born for the specialized physiology of S. cerevisiae.
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Affiliation(s)
- Zi-An Fang
- Université Paris Sud-11, CNRS UMR 8621, Institut de Génétique et Microbiologie, Orsay, France
- Institute of Genetics, State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China
| | - Guang-Hui Wang
- School of Mathematics, Shandong University, Jinan, Shandong, China
- Laboratoire Mathématiques Appliquées aux Systèmes, Ecole Centrale Paris, Châtenay-Malabry, France
| | - Ai-Lian Chen
- Department of Mathematics, Fuzhou University, Fuzhou, Fujian, China
| | - You-Fang Li
- Université Paris Sud-11, CNRS UMR 8621, Institut de Génétique et Microbiologie, Orsay, France
| | - Jian-Ping Liu
- Institute of Genetics, State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China
| | - Yu-Yang Li
- Institute of Genetics, State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China
| | | | - Wei-Guo Bao
- Université Paris Sud-11, CNRS UMR 8621, Institut de Génétique et Microbiologie, Orsay, France
- * E-mail:
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16
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van Hoek MJA, Hogeweg P. Metabolic adaptation after whole genome duplication. Mol Biol Evol 2009; 26:2441-53. [PMID: 19625390 DOI: 10.1093/molbev/msp160] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Whole genome duplications (WGDs) have been hypothesized to be responsible for major transitions in evolution. However, the effects of WGD and subsequent gene loss on cellular behavior and metabolism are still poorly understood. Here we develop a genome scale evolutionary model to study the dynamics of gene loss and metabolic adaptation after WGD. Using the metabolic network of Saccharomyces cerevisiae as an example, we primarily study the outcome of WGD on yeast as it currently is. However, similar results were obtained using a recontructed hypothetical metabolic network of the pre-WGD ancestor. We show that the retention of genes in duplicate in the model, corresponds nicely with those retained in duplicate after the ancestral WGD in S. cerevisiae. Also, we observe that transporter and glycolytic genes have a higher probability to be retained in duplicate after WGD and subsequent gene loss, both in the model as in S. cerevisiae, which leads to an increase in glycolytic flux after WGD. Furthermore, the model shows that WGD leads to better adaptation than small-scale duplications, in environments for which duplication of a whole pathway instead of single reactions is needed to increase fitness. This is indeed the case for adaptation to high glucose levels. Thus, our model confirms the hypothesis that WGD has been important in the adaptation of yeast to the new, glucose-rich environment that arose after the appearance of angiosperms. Moreover, the model shows that WGD is almost always detrimental on the short term in environments to which the lineage is preadapted, but can have immediate fitness benefits in "new" environments. This explains why WGD, while pivotal in the evolution of many lineages and an apparent "easy" genetic operator, occurs relatively rarely.
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Affiliation(s)
- Milan J A van Hoek
- Theoretical Biology/Bioinformatics Group, Utrecht University, Utrecht, The Netherlands.
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Merico A, Galafassi S, Piskur J, Compagno C. The oxygen level determines the fermentation pattern in Kluyveromyces lactis. FEMS Yeast Res 2009; 9:749-56. [PMID: 19500150 DOI: 10.1111/j.1567-1364.2009.00528.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Yeasts belonging to the lineage that underwent whole-genome duplication (WGD) possess a good fermentative potential and can proliferate in the absence of oxygen. In this study, we analyzed the pre-WGD yeast Kluyveromyces lactis and its ability to grow under oxygen-limited conditions. Under these conditions, K. lactis starts to increase the glucose metabolism and accumulates ethanol and glycerol. However, under more limited conditions, the fermentative metabolism decreases, causing a slow growth rate. In contrast, Saccharomyces cerevisiae and Saccharomyces kluyveri in anaerobiosis exhibit almost the same growth rate as in aerobiosis. In this work, we showed that in K. lactis, under oxygen-limited conditions, a decreased expression of RAG1 occurred. The activity of glucose-6-phosphate dehydrogenase also decreased, likely causing a reduced flux in the pentose phosphate pathway. Comparison of related and characterized yeasts suggests that the behavior observed in K. lactis could reflect the lack of an efficient mechanism to maintain a high glycolytic flux and to balance the redox homeostasis under hypoxic conditions. This could be a consequence of a recent specialization of K. lactis toward living in a niche where the ethanol accumulation at high oxygen concentrations and the ability to survive at a low oxygen concentration do not represent an advantage.
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Affiliation(s)
- Annamaria Merico
- Dipartimento di Scienze Biomolecolari e Biotecnologie, Università degli Studi di Milano, via Celoria 26, Milan, Italy
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Beck H, Dobritzsch D, Piškur J. Saccharomyces kluyverias a model organism to study pyrimidine degradation. FEMS Yeast Res 2008; 8:1209-13. [DOI: 10.1111/j.1567-1364.2008.00442.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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19
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Andersen G, Björnberg O, Polakova S, Pynyaha Y, Rasmussen A, Møller K, Hofer A, Moritz T, Sandrini MPB, Merico AM, Compagno C, Akerlund HE, Gojković Z, Piskur J. A second pathway to degrade pyrimidine nucleic acid precursors in eukaryotes. J Mol Biol 2008; 380:656-66. [PMID: 18550080 DOI: 10.1016/j.jmb.2008.05.029] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2008] [Revised: 05/09/2008] [Accepted: 05/10/2008] [Indexed: 11/16/2022]
Abstract
Pyrimidine bases are the central precursors for RNA and DNA, and their intracellular pools are determined by de novo, salvage and catabolic pathways. In eukaryotes, degradation of uracil has been believed to proceed only via the reduction to dihydrouracil. Using a yeast model, Saccharomyces kluyveri, we show that during degradation, uracil is not reduced to dihydrouracil. Six loci, named URC1-6 (for uracil catabolism), are involved in the novel catabolic pathway. Four of them, URC3,5, URC6, and URC2 encode urea amidolyase, uracil phosphoribosyltransferase, and a putative transcription factor, respectively. The gene products of URC1 and URC4 are highly conserved proteins with so far unknown functions and they are present in a variety of prokaryotes and fungi. In bacteria and in some fungi, URC1 and URC4 are linked on the genome together with the gene for uracil phosphoribosyltransferase (URC6). Urc1p and Urc4p are therefore likely the core components of this novel biochemical pathway. A combination of genetic and analytical chemistry methods demonstrates that uridine monophosphate and urea are intermediates, and 3-hydroxypropionic acid, ammonia and carbon dioxide the final products of degradation. The URC pathway does not require the presence of an active respiratory chain and is therefore different from the oxidative and rut pathways described in prokaryotes, although the latter also gives 3-hydroxypropionic acid as the end product. The genes of the URC pathway are not homologous to any of the eukaryotic or prokaryotic genes involved in pyrimidine degradation described to date.
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Affiliation(s)
- Gorm Andersen
- Department of Cell and Organism Biology, Lund University, 223 62 Lund, Sweden
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20
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Fekete V, Cierna M, Poláková S, Piskur J, Sulo P. Transition of the ability to generate petites in theSaccharomyces/Kluyveromycescomplex. FEMS Yeast Res 2007; 7:1237-47. [PMID: 17662054 DOI: 10.1111/j.1567-1364.2007.00287.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Petite-positivity - the ability to tolerate the loss of mtDNA - was examined after the treatment with ethidium bromide (EB) in over hundred isolates from the Saccharomyces/Kluyveromyces complex. The identity of petite mutants was confirmed by the loss of specific mtDNA DAPI staining patterns. Besides unequivocal petite-positive and petite-negative phenotypes, a few species exhibited temperature sensitive petite positive phenotype and petiteness of a few other species could be observed only at the elevated EB concentrations. Several yeast species displayed a mixed 'moot' phenotype, where a major part of the population did not tolerate the loss of mtDNA but several cells did. The genera from postwhole-genome duplication lineages (Saccharomyces, Kazachstania, Naumovia, Nakaseomyces) were invariably petite-positive. However, petite-positive traits could also be observed among the prewhole-genome duplication species.
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Affiliation(s)
- Veronika Fekete
- Comenius University, Faculty of Natural Sciences, Department of Biochemistry, Mlynská Dolina, Bratislava, Slovakia
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21
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Transcriptome analysis of Lactococcus lactis in coculture with Saccharomyces cerevisiae. Appl Environ Microbiol 2007; 74:485-94. [PMID: 17993564 DOI: 10.1128/aem.01531-07] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The study of microbial interactions in mixed cultures remains an important conceptual and methodological challenge for which transcriptome analysis could prove to be the essential method for improving our understanding. However, the use of whole-genome DNA chips is often restricted to the pure culture of the species for which the chips were designed. In this study, massive cross-hybridization was observed between the foreign cDNA and the specific Lactococcus lactis DNA chip. A very simple method is proposed to considerably decrease this nonspecific hybridization, consisting of adding the microbial partner's DNA. A correlation was established between the resulting cross-hybridization and the phylogenetic distance between the microbial partners. The response of L. lactis to the presence of Saccharomyces cerevisiae was analyzed during the exponential growth phase in fermentors under defined growth conditions. Although no differences between growth kinetics were observed for the pure and the mixed cultures of L. lactis, the mRNA levels of 158 genes were significantly modified. More particularly, a strong reorientation of pyrimidine metabolism was observed when L. lactis was grown in mixed cultures. These changes in transcript abundance were demonstrated to be regulated by the ethanol produced by the yeast and were confirmed by an independent method (quantitative reverse transcription-PCR).
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22
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Conant GC, Wolfe KH. Increased glycolytic flux as an outcome of whole-genome duplication in yeast. Mol Syst Biol 2007; 3:129. [PMID: 17667951 PMCID: PMC1943425 DOI: 10.1038/msb4100170] [Citation(s) in RCA: 161] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2007] [Accepted: 06/27/2007] [Indexed: 11/08/2022] Open
Abstract
After whole-genome duplication (WGD), deletions return most loci to single copy. However, duplicate loci may survive through selection for increased dosage. Here, we show how the WGD increased copy number of some glycolytic genes could have conferred an almost immediate selective advantage to an ancestor of Saccharomyces cerevisiae, providing a rationale for the success of the WGD. We propose that the loss of other redundant genes throughout the genome resulted in incremental dosage increases for the surviving duplicated glycolytic genes. This increase gave post-WGD yeasts a growth advantage through rapid glucose fermentation; one of this lineage's many adaptations to glucose-rich environments. Our hypothesis is supported by data from enzyme kinetics and comparative genomics. Because changes in gene dosage follow directly from post-WGD deletions, dosage selection can confer an almost instantaneous benefit after WGD, unlike neofunctionalization or subfunctionalization, which require specific mutations. We also show theoretically that increased fermentative capacity is of greatest advantage when glucose resources are both large and dense, an observation potentially related to the appearance of angiosperms around the time of WGD.
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Affiliation(s)
- Gavin C Conant
- Smurfit Institute of Genetics, Trinity College, University of Dublin, Dublin, Ireland.
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23
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Merico A, Sulo P, Piskur J, Compagno C. Fermentative lifestyle in yeasts belonging to the Saccharomyces complex. FEBS J 2007; 274:976-89. [PMID: 17239085 DOI: 10.1111/j.1742-4658.2007.05645.x] [Citation(s) in RCA: 185] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The yeast Saccharomyces cerevisiae is characterized by its ability to: (a) degrade glucose or fructose to ethanol, even in the presence of oxygen (Crabtree effect); (b) grow in the absence of oxygen; and (c) generate respiratory-deficient mitochondrial mutants, so-called petites. How unique are these properties among yeasts in the Saccharomyces clade, and what is their origin? Recent progress in genome sequencing has elucidated the phylogenetic relationships among yeasts in the Saccharomyces complex, providing a framework for the understanding of the evolutionary history of several modern traits. In this study, we analyzed over 40 yeasts that reflect over 150 million years of evolutionary history for their ability to ferment, grow in the absence of oxygen, and generate petites. A great majority of isolates exhibited good fermentation ability, suggesting that this trait could already be an intrinsic property of the progenitor yeast. We found that lineages that underwent the whole-genome duplication, in general, exhibit a fermentative lifestyle, the Crabtree effect, and the ability to grow without oxygen, and can generate stable petite mutants. Some of the pre-genome duplication lineages also exhibit some of these traits, but a majority of the tested species are petite-negative, and show a reduced Crabtree effect and a reduced ability to grow in the absence of oxygen. It could be that the ability to accumulate ethanol in the presence of oxygen, a gradual independence from oxygen and/or the ability to generate petites were developed later in several lineages. However, these traits have been combined and developed to perfection only in the lineage that underwent the whole-genome duplication and led to the modern Saccharomyces cerevisiae yeast.
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Affiliation(s)
- Annamaria Merico
- Dipartimento di Scienze Biomolecolari e Biotecnologie, Università degli Studi di Milano, Milan, Italy
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24
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Lai LC, Kosorukoff AL, Burke PV, Kwast KE. Metabolic-state-dependent remodeling of the transcriptome in response to anoxia and subsequent reoxygenation in Saccharomyces cerevisiae. EUKARYOTIC CELL 2006; 5:1468-89. [PMID: 16963631 PMCID: PMC1563586 DOI: 10.1128/ec.00107-06] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We conducted a comprehensive genomic analysis of the temporal response of yeast to anaerobiosis (six generations) and subsequent aerobic recovery ( approximately 2 generations) to reveal metabolic-state (galactose versus glucose)-dependent differences in gene network activity and function. Analysis of variance showed that far fewer genes responded (raw P value of <or=10(-8)) to the O(2) shifts in glucose (1,603 genes) than in galactose (2,388 genes). Gene network analysis reveals that this difference is due largely to the failure of "stress"-activated networks controlled by Msn2/4, Fhl1, MCB, SCB, PAC, and RRPE to transiently respond to the shift to anaerobiosis in glucose as they did in galactose. After approximately 1 generation of anaerobiosis, the response was similar in both media, beginning with the deactivation of Hap1 and Hap2/3/4/5 networks involved in mitochondrial functions and the concomitant derepression of Rox1-regulated networks for carbohydrate catabolism and redox regulation and ending (>or=2 generations) with the activation of Upc2- and Mot3-regulated networks involved in sterol and cell wall homeostasis. The response to reoxygenation was rapid (<5 min) and similar in both media, dominated by Yap1 networks involved in oxidative stress/redox regulation and the concomitant activation of heme-regulated ones. Our analyses revealed extensive networks of genes subject to combinatorial regulation by both heme-dependent (e.g., Hap1, Hap2/3/4/5, Rox1, Mot3, and Upc2) and heme-independent (e.g., Yap1, Skn7, and Puf3) factors under these conditions. We also uncover novel functions for several cis-regulatory sites and trans-acting factors and define functional regulons involved in the physiological acclimatization to changes in oxygen availability.
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Affiliation(s)
- Liang-Chuan Lai
- Department of Molecular and Integrative Physiology, University of Illinois, 524 Burrill Hall, 407 S. Goodwin Ave., Urbana, 61801, USA
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25
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Leeuw NJ, Swart CW, Ncango DM, Pohl CH, Sebolai OM, Strauss CJ, Botes PJ, van Wyk PWJ, Nigam S, Kock JLF. Acetylsalicylic acid as antifungal in Eremothecium and other yeasts. Antonie van Leeuwenhoek 2006; 91:393-405. [PMID: 17094014 DOI: 10.1007/s10482-006-9124-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2006] [Accepted: 10/09/2006] [Indexed: 02/01/2023]
Abstract
Interesting distribution patterns of acetylsalicylic acid (ASA, aspirin) sensitive 3-hydroxy (OH) oxylipins were previously reported in some representatives of the yeast genus Eremothecium--an important group of plant pathogens. Using immunofluorescence microscopy and 3-OH oxylipin specific antibodies in this study, we were able to map the presence of these compounds also in other Eremothecium species. In Eremothecium cymbalariae, these oxylipins were found to cover mostly the spiky tips of narrowly triangular ascospores while in Eremothecium gossypii, oxylipins covered the whole spindle-shaped ascospore with terminal appendages. The presence of these oxylipins was confirmed by chemical analysis. When ASA, a 3-OH oxylipin inhibitor, was added to these yeasts in increasing concentrations, the sexual stage was found to be the most sensitive. Our results suggest that 3-OH oxylipins, produced by mitochondria through incomplete beta-oxidation, are associated with the development of the sexual stages in both yeasts. Strikingly, preliminary studies on yeast growth suggest that yeasts, characterized by mainly an aerobic respiration rather than a fermentative pathway, are more sensitive to ASA than yeasts characterized by both pathways. These data further support the role of mitochondria in sexual as well as asexual reproduction of yeasts and its role to serve as a target for ASA antifungal action.
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Affiliation(s)
- N J Leeuw
- Industrial Biotechnology, Department of Microbial, Biochemical and Food Biotechnology, UNESCO MIRCEN, University of the Free State, P.O. Box 339, Bloemfontein, South Africa
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26
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Clark-Walker GD. Kinetic properties of F1-ATPase influence the ability of yeasts to grow in anoxia or absence of mtDNA. Mitochondrion 2005; 2:257-65. [PMID: 16120326 DOI: 10.1016/s1567-7249(02)00107-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2002] [Revised: 10/22/2002] [Accepted: 11/06/2002] [Indexed: 10/27/2022]
Abstract
A mechanism for hypoxia survival by eukaryotic cells is suggested from studies on the petite mutation of yeasts. Previous work has shown that mutations in the alpha, beta and gamma subunit genes of F1-ATPase can suppress lethality due to loss of the mitochondrial genome from the petite-negative yeast Kluyveromyceslactis. Here it is reported that suppressor mutations appear to increase the affinity of F1-ATPase for ATP. Extension of this study to other yeasts shows that petite-positive species have a higher affinity for ATP in the hydrolysis reaction than petite-negative species. Possession of a F1-ATPase with a low K(m) for ATP is considered to be an adaptation for hypoxic growth, enabling maintenance of the mitochondrial inner membrane potential, deltapsi, by enhanced export of protons through F1F0-ATP synthase connected to increased ATP hydrolysis at low substrate concentration.
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Affiliation(s)
- G Desmond Clark-Walker
- Molecular Genetics and Evolution Group, Research School of Biological Sciences, The Australian National University, G.P.O. Box 475, Canberra City, ACT 2601, Australia.
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27
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Alper H, Fischer C, Nevoigt E, Stephanopoulos G. Tuning genetic control through promoter engineering. Proc Natl Acad Sci U S A 2005; 102:12678-83. [PMID: 16123130 PMCID: PMC1200280 DOI: 10.1073/pnas.0504604102] [Citation(s) in RCA: 639] [Impact Index Per Article: 33.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Gene function is typically evaluated by sampling the continuum of gene expression at only a few discrete points corresponding to gene knockout or overexpression. We argue that this characterization is incomplete and present a library of engineered promoters of varying strengths obtained through mutagenesis of a constitutive promoter. A multifaceted characterization of the library, especially at the single-cell level to ensure homogeneity, permitted quantitative assessment correlating the effect of gene expression levels to improved growth and product formation phenotypes in Escherichia coli. Integration of these promoters into the chromosome can allow for a quantitative accurate assessment of genetic control. To this end, we used the characterized library of promoters to assess the impact of phosphoenolpyruvate carboxylase levels on growth yield and deoxy-xylulose-P synthase levels on lycopene production. The multifaceted characterization of promoter strength enabled identification of optimal expression levels for ppc and dxs, which maximized the desired phenotype. Additionally, in a strain preengineered to produce lycopene, the response to deoxy-xylulose-P synthase levels was linear at all levels tested, indicative of a rate-limiting step, unlike the parental strain, which exhibited an optimum expression level, illustrating that optimal gene expression levels are variable and dependent on the genetic background of the strain. This promoter library concept is illustrated as being generalizable to eukaryotic organisms (Saccharomyces cerevisiae) and thus constitutes an integral platform for functional genomics, synthetic biology, and metabolic engineering endeavors.
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Affiliation(s)
- Hal Alper
- Department of Chemical Engineering, Massachusetts Institute of Technology, Room 56-469, Cambridge, MA 02139, USA
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28
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Verma M, Bhat P, Venkatesh K. Steady-state analysis of glucose repression reveals hierarchical expression of proteins under Mig1p control in Saccharomyces cerevisiae. Biochem J 2005; 388:843-9. [PMID: 15698380 PMCID: PMC1183464 DOI: 10.1042/bj20041883] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2004] [Revised: 01/13/2005] [Accepted: 02/08/2005] [Indexed: 11/17/2022]
Abstract
Glucose repression is a global transcriptional regulatory mechanism commonly observed in micro-organisms for the repression of enzymes that are not essential for glucose metabolism. In Saccharomyces cerevisiae, Mig1p, a homologue of Wilms' tumour protein, is a global repressor protein dedicated to glucose repression. Mig1p represses genes either by binding directly to the upstream repression sequence of structural genes or by indirectly repressing a transcriptional activator, such as Gal4p. In addition, some genes are repressed by both of the above mechanisms. This raises a fundamental question regarding the physiological relevance of the varied mechanisms of repression that exist involving Mig1p. We address this issue by comparing two well-known glucose-repression systems, that is, SUC2 and GAL gene expression systems, which encompass all the above three mechanisms. We demonstrate using steady-state analysis that these mechanisms lead to a hierarchical glucose repression profile of different family of genes. This switch over from one carbon source to another is well-calibrated as a function of glucose concentration through this hierarchical transcriptional response. The mechanisms prevailing in this repression system can achieve amplification and sensitivity, as observed in the well-characterized MAPK (mitogen-activated protein kinase) cascade system, albeit through a different structure. A critical feature of repression predicted by our steady-state model for the mutant strain of S. cerevisiae lacking Gal80p agrees well with the data reported here as well as that available in the literature.
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Affiliation(s)
- Malkhey Verma
- *Department of Chemical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai-400076, India
| | - Paike J. Bhat
- †School of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai-400076, India
| | - K. V. Venkatesh
- *Department of Chemical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai-400076, India
- †School of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai-400076, India
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29
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Bhat PJ, Venkatesh KV. Stochastic variation in the concentration of a repressor activates GAL genetic switch: implications in evolution of regulatory network. FEBS Lett 2005; 579:597-603. [PMID: 15670814 DOI: 10.1016/j.febslet.2004.12.038] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2004] [Accepted: 12/13/2004] [Indexed: 11/30/2022]
Abstract
In Saccharomyces cerevisiae, a recessive mutation in the signal transducer encoded by GAL3 leads to a significant lag in the induction of GAL genes, referred to as long term adaptation phenotype (LTA). Further, gal3 mutation in combination with other genetic defects leads to the non-inducibility of GAL genes. It was shown that the expression of GAL1 encoded galactokinase, a redundant GAL3 like signal transducer, eventually substitutes for the lack of GAL3 signal transduction function. However, how GAL1 gets induced in the absence of GAL3 is not clear. We hypothesize that GAL1 induction in gal3 cells exposed to galactose is due to a stochastic decrease in the repressor, Gal80p concentration, leading to heterogeneity in the population. This observation explains not only LTA observed in gal3 cells but also explains the non-inducibility of gal3 mutants in combination with other genetic defects. By recruiting a dedicated signal transducer, GAL3, S. cerevisiae GAL switch has evolved to overcome the fortuitous induction, which occurs due to low signal to noise ratio in certain mutants of Escherichia coli and Kluveromyces lactis.
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Affiliation(s)
- Paike Jayadeva Bhat
- School of Biosciences & Bioengineering, Indian Institute of Technology, Powai, Mumbai 400 076, India.
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30
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Zameitat E, Knecht W, Piskur J, Löffler M. Two different dihydroorotate dehydrogenases from yeast Saccharomyces kluyveri. FEBS Lett 2004; 568:129-34. [PMID: 15196933 DOI: 10.1016/j.febslet.2004.05.017] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2004] [Revised: 04/30/2004] [Accepted: 05/13/2004] [Indexed: 11/29/2022]
Abstract
Genes for two structurally and functionally different dihydroorotate dehydrogenases (DHODHs, EC 1.3.99.11), catalyzing the fourth step of pyrimidine biosynthesis, have been previously found in yeast Saccharomyces kluyveri. One is closely related to the Schizosaccharomyces pombe mitochondrial family 2 enzymes, which use quinones as direct and oxygen as the final electron acceptor. The other one resembles the Saccharomyces cerevisiae cytosolic family 1A fumarate-utilizing DHODH. The DHODHs from S. kluyveri, Sch. pombe and S. cerevisiae, were expressed in Escherichia coli and compared for their biochemical properties and interaction with inhibitors. Benzoates as pyrimidine ring analogs were shown to be selective inhibitors of cytosolic DHODs. This unique property of Saccharomyces DHODHs could appoint DHODH as a species-specific target for novel anti-fungal therapeutics.
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Affiliation(s)
- Elke Zameitat
- Institute for Physiological Chemistry, Philipps-University, Karl-von-Frisch-Strasse 1, D-35033 Marburg, Germany.
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31
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Abstract
For decades, unicellular yeasts have been general models to help understand the eukaryotic cell and also our own biology. Recently, over a dozen yeast genomes have been sequenced, providing the basis to resolve several complex biological questions. Analysis of the novel sequence data has shown that the minimum number of genes from each species that need to be compared to produce a reliable phylogeny is about 20. Yeast has also become an attractive model to study speciation in eukaryotes, especially to understand molecular mechanisms behind the establishment of reproductive isolation. Comparison of closely related species helps in gene annotation and to answer how many genes there really are within the genomes. Analysis of non-coding regions among closely related species has provided an example of how to determine novel gene regulatory sequences, which were previously difficult to analyse because they are short and degenerate and occupy different positions. Comparative genomics helps to understand the origin of yeasts and points out crucial molecular events in yeast evolutionary history, such as whole-genome duplication and horizontal gene transfer(s). In addition, the accumulating sequence data provide the background to use more yeast species in model studies, to combat pathogens and for efficient manipulation of industrial strains.
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Affiliation(s)
- Jure Piskur
- BioCentrum-DTU, Building 301, Technical University of Denmark, DK-2800 Kgl. Lyngby, Denmark.
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32
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Gojković Z, Knecht W, Zameitat E, Warneboldt J, Coutelis JB, Pynyaha Y, Neuveglise C, Møller K, Löffler M, Piskur J. Horizontal gene transfer promoted evolution of the ability to propagate under anaerobic conditions in yeasts. Mol Genet Genomics 2004; 271:387-93. [PMID: 15014982 DOI: 10.1007/s00438-004-0995-7] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2003] [Accepted: 02/19/2004] [Indexed: 10/26/2022]
Abstract
The ability to propagate under anaerobic conditions is an essential and unique trait of brewer's or baker's yeast ( Saccharomyces cervisiae). To understand the evolution of facultative anaerobiosis we studied the dependence of de novo pyrimidine biosynthesis, more precisely the fourth enzymic activity catalysed by dihydroorotate dehydrogenase (DHODase), on the enzymes of the respiratory chain in several yeast species. While the majority of yeasts possess a mitochondrial DHODase, Saccharomyces cerevisiae has a cytoplasmatic enzyme, whose activity is independent of the presence of oxygen. From the phylogenetic point of view, this enzyme is closely related to a bacterial DHODase from Lactococcus lactis. Here we show that S. kluyveri, which separated from the S. cerevisiae lineage more than 100 million years ago, represents an evolutionary intermediate, having both cytoplasmic and mitochondrial DHODases. We show that these two S. kluyveri enzymes, and their coding genes, differ in their dependence on the presence of oxygen. Only the cytoplasmic DHODase promotes growth in the absence of oxygen. Apparently a Saccharomyces yeast progenitor which had a eukaryotic-like mitochondrial DHODase acquired a bacterial gene for DHODase, which subsequently allowed cell growth gradually to become independent of oxygen.
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Affiliation(s)
- Z Gojković
- BioCentrum-DTU, Building 301, Technical University of Denmark, 2800 Lyngby, Denmark
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33
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Møller K, Langkjaer RB, Nielsen J, Piskur J, Olsson L. Pyruvate decarboxylases from the petite-negative yeast Saccharomyces kluyveri. Mol Genet Genomics 2003; 270:558-68. [PMID: 14648197 DOI: 10.1007/s00438-003-0950-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2003] [Accepted: 10/20/2003] [Indexed: 10/26/2022]
Abstract
Saccharomyces kluyveri is a petite-negative yeast, which is less prone to form ethanol under aerobic conditions than is S. cerevisiae. The first reaction on the route from pyruvate to ethanol is catalysed by pyruvate decarboxylase, and the differences observed between S. kluyveri and S. cerevisiae with respect to ethanol formation under aerobic conditions could be caused by differences in the regulation of this enzyme activity. We have identified and cloned three genes encoding functional pyruvate decarboxylase enzymes (PDCgenes) from the type strain of S. kluyveri (Sk- PDC11, Sk- PDC12 and Sk- PDC13). The regulation of pyruvate decarboxylase in S. kluyveri was studied by measuring the total level of Sk- PDC mRNA and the overall enzyme activity under various growth conditions. It was found that the level of Sk- PDC mRNA was enhanced by glucose and oxygen limitation, and that the level of enzyme activity was controlled by variations in the amount of mRNA. The mRNA level and the pyruvate decarboxylase activity responded to anaerobiosis and growth on different carbon sources in essentially the same fashion as in S. cerevisiae. This indicates that the difference in ethanol formation between these two yeasts is not due to differences in the regulation of pyruvate decarboxylase(s), but rather to differences in the regulation of the TCA cycle and the respiratory machinery. However, the PDC genes of Saccharomyces/ Kluyveromyces yeasts differ in their genetic organization and phylogenetic origin. While S. cerevisiae and S. kluyveri each have three PDC genes, these have apparently arisen by independent duplications and specializations in each of the two yeast lineages.
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Affiliation(s)
- K Møller
- Center for Process Biotechnology, BioCentrum-DTU, Technical University of Denmark, Building 223, 2800 Lyngby, Denmark.
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Herwig C, Von Stockar U. Quantitative comparison of transient growth of Saccharomyces cerevisiae, Saccharomyces kluyveri, and Kluyveromyces lactis. Biotechnol Bioeng 2003; 81:837-47. [PMID: 12557317 DOI: 10.1002/bit.10529] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A multitude of metabolic regulations occur in yeast, particularly under dynamic process conditions, such as under sudden glucose excess. However, quantification of regulations and classification of yeast strains under these conditions have yet to be elucidated, which requires high-frequency and consistent quantification of the metabolic response. The present study aimed at quantifying the dynamic regulation of the central metabolism of strains Saccharomyces cerevisiae, S. kluyveri, and Kluyveromyces lactis upon sudden glucose excess, accomplished by a shift-up in dilution rate inside of the oxidative region using a small metabolic flux model. It was found that, under transient growth conditions, S. kluyveri behaved like K. lactis, while classification using steady-state conditions would position S. kluyveri close to S. cerevisiae. For transient conditions and based on the observation whether excess glucose is initially used for catabolism (energy) or anabolism (carbon), we propose to classify strains into energy-driven, such as S. cerevisiae, and carbon-driven, such as S. kluyveri and K. lactis, strains. Furthermore, it was found that the delayed onset of fermentative catabolism in carbon-driven strains is a consequence of low catabolic flux and the initial shunt of glucose in non-nitrogen-containing biomass constituents. The MFA model suggests that energy limitation forced the cell to ultimately increase catabolic flux, while the capacity of oxidative catabolism is not sufficient to process this flux oxidatively. The combination of transient experiments and its exploitation with reconciled intrinsic rates using a small metabolic model could corroborate earlier findings of metabolic regulations, such as tight glucose control in carbon-driven strains and transient changes in biomass composition, as well as explore new regulations, such as assimilation of ethanol before glucose. The benefit from using small metabolic flux models is the richness of information and the enhanced insight into intrinsic metabolic pathways without a priori knowledge of adaptation kinetics. Used in an online context, this approach serves as an efficient tool for strain characterization and physiological studies.
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Affiliation(s)
- Christoph Herwig
- Laboratory of Chemical and Biochemical Engineering, Swiss Federal Institute of Technology Lausanne (EPFL), CH-1015 Lausanne, Switzerland
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35
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Lefebvre-Legendre L, Balguerie A, Duvezin-Caubet S, Giraud MF, Slonimski PP, Di Rago JP. F1-catalysed ATP hydrolysis is required for mitochondrial biogenesis in Saccharomyces cerevisiae growing under conditions where it cannot respire. Mol Microbiol 2003; 47:1329-39. [PMID: 12603738 DOI: 10.1046/j.1365-2958.2003.03371.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Mutant strains of yeast Saccharomyces cerevisiae lacking a functional F1-ATPase were found to grow very poorly under anaerobic conditions. A single amino acid replacement (K222 > E222) that locally disrupts the adenine nucleotide catalytic site in the beta-F1 subunit was sufficient to compromise anaerobic growth. This mutation also affected growth in aerated conditions when ethidium bromide (an intercalating agent impairing mtDNA propagation) or antimycin (an inhibitor of respiration) was included in the medium. F1-deficient cells forced to grow in oxygen-limited conditions were shown to lose their mtDNA completely and to accumulate Hsp60p mainly under its precursor form. Fluorescence microscopy analyses with a modified GFP containing a mitochondrial targeting presequence revealed that aerobically growing F1-deficient cells stopped importing the GFP when antimycin was added to the medium. Finally, after total inactivation of the catalytic alpha3beta3 subcomplex of F1, mitochondria could no longer be energized by externally added ATP because of either a block in assembly or local disruption of the adenine nucleotide processing site. Altogether these data strengthen the notion that in the absence of respiration, and whether the proton translocating domain (F0) of complex V is present or not, F1-catalysed hydrolysis of ATP is essential for the occurrence of vital cellular processes depending on the maintenance of an electrochemical potential across the mitochondrial inner membrane.
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Affiliation(s)
- Linnka Lefebvre-Legendre
- Institut de Biochimie et Génétique Cellulaires du CNRS, Université Victor Ségalen, Bordeaux 2, 33077 Bordeaux cedex, France
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36
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Langkjaer RB, Cliften PF, Johnston M, Piskur J. Yeast genome duplication was followed by asynchronous differentiation of duplicated genes. Nature 2003; 421:848-52. [PMID: 12594514 DOI: 10.1038/nature01419] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2002] [Accepted: 01/03/2003] [Indexed: 11/09/2022]
Abstract
Gene redundancy has been observed in yeast, plant and human genomes, and is thought to be a consequence of whole-genome duplications. Baker's yeast, Saccharomyces cerevisiae, contains several hundred duplicated genes. Duplication(s) could have occurred before or after a given speciation. To understand the evolution of the yeast genome, we analysed orthologues of some of these genes in several related yeast species. On the basis of the inferred phylogeny of each set of genes, we were able to deduce whether the gene duplicated and/or specialized before or after the divergence of two yeast lineages. Here we show that the gene duplications might have occurred as a single event, and that it probably took place before the Saccharomyces and Kluyveromyces lineages diverged from each other. Further evolution of each duplicated gene pair-such as specialization or differentiation of the two copies, or deletion of a single copy--has taken place independently throughout the evolution of these species.
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Affiliation(s)
- Rikke B Langkjaer
- BioCentrum-DTU, Technical University of Denmark, Building 301, DK-2800 Lyngby, Denmark
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37
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Petersen RF, Langkjaer RB, Hvidtfeldt J, Gartner J, Palmen W, Ussery DW, Piskur J. Inheritance and organisation of the mitochondrial genome differ between two Saccharomyces yeasts. J Mol Biol 2002; 318:627-36. [PMID: 12054811 DOI: 10.1016/s0022-2836(02)00037-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Petite-positive Saccharomyces yeasts can be roughly divided into the sensu stricto, including Saccharomyces cerevisiae, and sensu lato group, including Saccharomyces castellii; the latter was recently studied for transmission and the organisation of its mitochondrial genome. S. castellii mitochondrial molecules (mtDNA) carrying point mutations, which confer antibiotic resistance, behaved in genetic crosses as the corresponding point mutants of S. cerevisiae. While S. castellii generated spontaneous petite mutants in a similar way as S. cerevisiae, the petites exhibited a different inheritance pattern. In crosses with the wild type strains a majority of S. castellii petites was neutral, and the suppressivity in suppressive petites was never over 50%. The two yeasts also differ in organisation of their mtDNA molecules. The 25,753 bp sequence of S. castellii mtDNA was determined and the coding potential of both yeasts is similar. However, the S. castellii intergenic sequences are much shorter and do not contain sequences homologous to the S. cerevisiae biologically active intergenic sequences, as ori/rep/tra, which are responsible for the hyper-suppressive petite phenotype found in S. cerevisiae. The structure of one suppressive S. castellii mutant, CA38, was also determined. Apparently, a short direct intergenic repeat was involved in the generation of this petite mtDNA molecule.
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Affiliation(s)
- Randi F Petersen
- BioCentrum-DTU, Technical University of Denmark, Building 301, DK-2800 Kgl. Lyngby, Denmark
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Møller K, Bro C, Piskur J, Nielsen J, Olsson L. Steady-state and transient-state analyses of aerobic fermentation in Saccharomyces kluyveri. FEMS Yeast Res 2002; 2:233-44. [PMID: 12702311 DOI: 10.1111/j.1567-1364.2002.tb00088.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Some yeasts, such as Saccharomyces cerevisiae, produce ethanol at fully aerobic conditions, whereas other yeasts, such as Kluyveromyces lactis, do not. In this study we investigated the occurrence of aerobic alcoholic fermentation in the petite-negative yeast Saccharomyces kluyveri that is only distantly related to S. cerevisiae. In aerobic glucose-limited continuous cultures of S. kluyveri, two growth regimens were observed: at dilution rates below 0.5 h(-1) the metabolism was purely respiratory, and at dilution rates above 0.5 h(-1) the metabolism was respiro-fermentative. The dilution rate at which the switch in metabolism occurred, i.e. the critical dilution rate, was 66% higher than the typical critical dilution rate of S. cerevisiae. The maximum specific oxygen consumption rate around the critical dilution rate was found to 13.6 mmol (g dry weight)(-1) h(-1) and the capacity of the pyruvate dehydrogenase-bypass pathway was estimated to be high from in vitro enzyme activities; especially the specific activity of acetyl-CoA synthetase was much higher than in S. cerevisiae at all tested conditions. Addition of glucose to respiring cells of S. kluyveri led to ethanol formation after a delay of 20-50 min (depending on culture conditions prior to the pulse), which is in contrast to S. cerevisiae that ferments immediately after glucose addition.
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Affiliation(s)
- Kasper Møller
- Center for Process Biotechnology, BioCentrum-DTU, Technical University of Denmark, Building 223, 2800 Lyngby, Denmark
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Møller K, Christensen B, Förster J, Piskur J, Nielsen J, Olsson L. Aerobic glucose metabolism of Saccharomyces kluyveri: growth, metabolite production, and quantification of metabolic fluxes. Biotechnol Bioeng 2002; 77:186-93. [PMID: 11753925 DOI: 10.1002/bit.10122] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The growth and product formation of Saccharomyces kluyveri was characterized in aerobic batch cultivation on glucose. At these conditions it was found that ethyl acetate was a major overflow metabolite in S. kluyveri. During the exponential-growth phase on glucose ethyl acetate was produced at a constant specific rate of 0.12 g ethyl acetate per g dry weight per hour. The aerobic glucose metabolism in S. kluyveri was found to be less fermentative than in S. cerevisiae, as illustrated by the comparably low yield of ethanol on glucose (0.08 +/- 0.02 g/g), and high yield of biomass on glucose (0.29 +/- 0.01 g/g). The glucose metabolism of S. kluyveri was further characterized by the new and powerful techniques of metabolic network analysis. Flux distributions in the central carbon metabolism were estimated for respiro-fermentative growth in aerobic batch cultivation on glucose and respiratory growth in aerobic glucose-limited continuous cultivation. It was found that in S. kluyveri the flux into the pentose phosphate pathway was 18.8 mmole per 100 mmole glucose consumed during respiratory growth in aerobic glucose-limited continuous cultivation. Such a low flux into the pentose phosphate pathway cannot provide the cell with enough NADPH for biomass formation which is why the remaining NADPH will have to be provided by another pathway. During batch cultivation of S. kluyveri the tricarboxylic acid cycle was working as a cycle with a considerable flux, that is in sharp contrast to what has previously been observed in S. cerevisiae at the same growth conditions, where the tricarboxylic acid cycle operates as two branches. This indicates that the respiratory system was not significantly repressed in S. kluyveri during batch cultivation on glucose.
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Affiliation(s)
- Kasper Møller
- Center for Process Biotechnology, BioCentrum-DTU, Technical University of Denmark, Building 223, 2800 Lyngby, Denmark
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40
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Kwast KE, Lai LC, Menda N, James DT, Aref S, Burke PV. Genomic analyses of anaerobically induced genes in Saccharomyces cerevisiae: functional roles of Rox1 and other factors in mediating the anoxic response. J Bacteriol 2002; 184:250-65. [PMID: 11741867 PMCID: PMC134782 DOI: 10.1128/jb.184.1.250-265.2002] [Citation(s) in RCA: 193] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
DNA arrays were used to investigate the functional role of Rox1 in mediating acclimatization to anaerobic conditions in Saccharomyces cerevisiae. Multiple growth conditions for wild-type and rox1 null strains were used to identify open reading frames with a statistically robust response to this repressor. These results were compared to those obtained for a wild-type strain in response to oxygen availability. Transcripts of nearly one-sixth of the genome were differentially expressed (P < 0.05) with respect to oxygen availability, the majority (>65%) being down-regulated under anoxia. Of the anaerobically induced genes, about one-third (106) contain putative Rox1-binding sites in their promoters and were significantly (P < 0.05) up-regulated in the rox1 null strains under aerobiosis. Additional promoter searches revealed that nearly one-third of the anaerobically induced genes contain an AR1 site(s) for the Upc2 transcription factor, suggesting that Upc2 and Rox1 regulate the majority of anaerobically induced genes in S. cerevisiae. Functional analyses indicate that a large fraction of the anaerobically induced genes are involved in cell stress (approximately 1/3), cell wall maintenance (approximately 1/8), carbohydrate metabolism (approximately 1/10), and lipid metabolism (approximately 1/12), with both Rox1 and Upc2 predominating in the regulation of this latter group and Upc2 predominating in cell wall maintenance. Mapping the changes in expression of functional regulons onto metabolic pathways has provided novel insight into the role of Rox1 and other trans-acting factors in mediating the physiological response of S. cerevisiae to anaerobic conditions.
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Affiliation(s)
- Kurt E Kwast
- Department of Molecular & Integrative Physiology, University of Illinois, Urbana, Illinois 61801, USA.
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Abstract
The genome of Saccharomyces cerevisiae contains several duplicated regions. The recent sequencing results of several yeast species suggest that the duplicated regions found in the modern Saccharomyces species are probably the result of a single gross duplication, as well as a series of sporadic independent short-segment duplications. The gross duplication might coincide with the origin of the ability to grow under anaerobic conditions.
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Affiliation(s)
- J Piskur
- Section of Molecular Microbiology, BioCentrum-DTU Technical University of Denmark, Building 301, DK-2800 Lyngby, Denmark.
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42
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Current Awareness. Yeast 2001. [DOI: 10.1002/yea.687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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