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Baeza M, Zúñiga S, Peragallo V, Gutierrez F, Barahona S, Alcaino J, Cifuentes V. Response to Cold: A Comparative Transcriptomic Analysis in Eight Cold-Adapted Yeasts. Front Microbiol 2022; 13:828536. [PMID: 35283858 PMCID: PMC8905146 DOI: 10.3389/fmicb.2022.828536] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 01/19/2022] [Indexed: 02/03/2023] Open
Abstract
Microorganisms have evolved to colonize all biospheres, including extremely cold environments, facing several stressor conditions, mainly low/freezing temperatures. In general, terms, the strategies developed by cold-adapted microorganisms include the synthesis of cryoprotectant and stress-protectant molecules, cold-active proteins, especially enzymes, and membrane fluidity regulation. The strategy could differ among microorganisms and concerns the characteristics of the cold environment of the microorganism, such as seasonal temperature changes. Microorganisms can develop strategies to grow efficiently at low temperatures or tolerate them and grow under favorable conditions. These differences can be found among the same kind of microorganisms and from the same cold habitat. In this work, eight cold-adapted yeasts isolated from King George Island, subAntarctic region, which differ in their growth properties, were studied about their response to low temperatures at the transcriptomic level. Sixteen ORFeomes were assembled and used for gene prediction and functional annotation, determination of gene expression changes, protein flexibilities of translated genes, and codon usage bias. Putative genes related to the response to all main kinds of stress were found. The total number of differentially expressed genes was related to the temperature variation that each yeast faced. The findings from multiple comparative analyses among yeasts based on gene expression changes and protein flexibility by cellular functions and codon usage bias raise significant differences in response to cold among the studied Antarctic yeasts. The way a yeast responds to temperature change appears to be more related to its optimal temperature for growth (OTG) than growth velocity. Yeasts with higher OTG prepare to downregulate their metabolism to enter the dormancy stage. In comparison, yeasts with lower OTG perform minor adjustments to make their metabolism adequate and maintain their growth at lower temperatures.
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Affiliation(s)
- Marcelo Baeza
- Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Santiago, Chile.,Centro de Biotecnología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Sergio Zúñiga
- Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Vicente Peragallo
- Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Fernando Gutierrez
- Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Salvador Barahona
- Centro de Biotecnología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Jennifer Alcaino
- Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Santiago, Chile.,Centro de Biotecnología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Víctor Cifuentes
- Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Santiago, Chile.,Centro de Biotecnología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
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2
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Morales-Polanco F, Bates C, Lui J, Casson J, Solari CA, Pizzinga M, Forte G, Griffin C, Garner KEL, Burt HE, Dixon HL, Hubbard S, Portela P, Ashe MP. Core Fermentation (CoFe) granules focus coordinated glycolytic mRNA localization and translation to fuel glucose fermentation. iScience 2021; 24:102069. [PMID: 33554071 PMCID: PMC7859310 DOI: 10.1016/j.isci.2021.102069] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 12/16/2020] [Accepted: 01/12/2021] [Indexed: 12/24/2022] Open
Abstract
Glycolysis is a fundamental metabolic pathway for glucose catabolism across biology, and glycolytic enzymes are among the most abundant proteins in cells. Their expression at such levels provides a particular challenge. Here we demonstrate that the glycolytic mRNAs are localized to granules in yeast and human cells. Detailed live cell and smFISH studies in yeast show that the mRNAs are actively translated in granules, and this translation appears critical for the localization. Furthermore, this arrangement is likely to facilitate the higher level organization and control of the glycolytic pathway. Indeed, the degree of fermentation required by cells is intrinsically connected to the extent of mRNA localization to granules. On this basis, we term these granules, core fermentation (CoFe) granules; they appear to represent translation factories, allowing high-level coordinated enzyme synthesis for a critical metabolic pathway.
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Affiliation(s)
- Fabian Morales-Polanco
- School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
| | - Christian Bates
- School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
| | - Jennifer Lui
- School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
| | - Joseph Casson
- School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
| | - Clara A Solari
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, IQUIBICEN-CONICET, Buenos Aires, Argentina
| | - Mariavittoria Pizzinga
- School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
| | - Gabriela Forte
- School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
| | - Claire Griffin
- School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
| | - Kirsten E L Garner
- School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
| | - Harriet E Burt
- School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
| | - Hannah L Dixon
- School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
| | - Simon Hubbard
- School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
| | - Paula Portela
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, IQUIBICEN-CONICET, Buenos Aires, Argentina
| | - Mark P Ashe
- School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
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Improvement of stress tolerance and riboflavin production of Bacillus subtilis by introduction of heat shock proteins from thermophilic bacillus strains. Appl Microbiol Biotechnol 2019; 103:4455-4465. [PMID: 30968162 DOI: 10.1007/s00253-019-09788-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 03/12/2019] [Accepted: 03/19/2019] [Indexed: 10/27/2022]
Abstract
In this study, stress tolerance devices consisting of heat shock protein (HSP) genes from thermophiles Geobacillus and Parageobacillus were introduced into riboflavin-producing strain Bacillus subtilis 446 to improve its stress tolerance and riboflavin production. The 12 HSP homologs were selected from 28 Geobacillus and Parageobacillus genomes according to their sequence clustering and phylogenetically analysis which represents the diversity of HSPs from thermophilic bacillus. The 12 HSP genes and 2 combinations of them (PtdnaK-PtdnaJ-PtgrpE and PtgroeL-PtgroeS) were heterologously expressed in B. subtilis 446 under the control of a strong constitutive promoter P43. Most of the 14 engineered strains showed increased cell density at 44 to 48 °C and less cell death at 50 °C compared with the control strains. Among them, strains B.s446-HSP20-3, B.s446-HSP20-2, and B.s446-PtDnaK-PtDnaJ-PtGrpE increased their cell densities over 25% at 44 to 48 °C. They also showed 5-, 4-, and 4-fold improved cell survivals after the 10-h heat shock treatment at 50 °C, respectively. These three strains also showed reduced cell death rates under osmotic stress of 10% NaCl, indicating that the introduction of HSPs improved not only the heat tolerance of B. subtilis 446 but also its osmotic tolerance. Fermentation of these three strains at higher temperatures of 39 and 43 °C showed 23-66% improved riboflavin titers, as well as 24-h shortened fermentation period. These results indicated that implanting HSPs from thermophiles to B. subtilis 446 would be an efficient approach to improve its stress tolerance and riboflavin production.
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Dong Z, Chen X, Cai K, Shen P, Tian K, Jin P, Liu X, Wang Z. Overexpression of the Bacillus licheniformis GroES enhances thermotolerance of Bacillus subtilis WB600. BIOTECHNOL BIOTEC EQ 2018. [DOI: 10.1080/13102818.2018.1517029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
Affiliation(s)
- Zixing Dong
- Department of Biochemical Engineering, College of Chemical Engineering and Materials Science, Tianjin University of Science & Technology, Tianjin, PR China
| | - Xiaoling Chen
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, College of Biotechnology, Tianjin University of Science & Technology, Tianjin, PR China
| | - Ke Cai
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, College of Biotechnology, Tianjin University of Science & Technology, Tianjin, PR China
| | - Peili Shen
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, College of Biotechnology, Tianjin University of Science & Technology, Tianjin, PR China
| | - Kangming Tian
- Department of Biochemical Engineering, College of Chemical Engineering and Materials Science, Tianjin University of Science & Technology, Tianjin, PR China
| | - Peng Jin
- Department of Biochemical Engineering, College of Chemical Engineering and Materials Science, Tianjin University of Science & Technology, Tianjin, PR China
| | - Xiaoguang Liu
- Department of Biochemical Engineering, College of Chemical Engineering and Materials Science, Tianjin University of Science & Technology, Tianjin, PR China
| | - Zhengxiang Wang
- Department of Biochemical Engineering, College of Chemical Engineering and Materials Science, Tianjin University of Science & Technology, Tianjin, PR China
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, College of Biotechnology, Tianjin University of Science & Technology, Tianjin, PR China
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Lahtvee PJ, Kumar R, Hallström BM, Nielsen J. Adaptation to different types of stress converge on mitochondrial metabolism. Mol Biol Cell 2016; 27:2505-14. [PMID: 27307591 PMCID: PMC4966989 DOI: 10.1091/mbc.e16-03-0187] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 06/08/2016] [Indexed: 01/12/2023] Open
Abstract
Yeast cell factories encounter physical and chemical stresses when used for industrial production of fuels and chemicals. These stresses reduce productivity and increase bioprocess costs. Understanding the mechanisms of the stress response is essential for improving cellular robustness in platform strains. We investigated the three most commonly encountered industrial stresses for yeast (ethanol, salt, and temperature) to identify the mechanisms of general and stress-specific responses under chemostat conditions in which specific growth rate-dependent changes are eliminated. By applying systems-level analysis, we found that most stress responses converge on mitochondrial processes. Our analysis revealed that stress-specific factors differ between applied stresses; however, they are underpinned by an increased ATP demand. We found that when ATP demand increases to high levels, respiration cannot provide sufficient ATP, leading to onset of respirofermentative metabolism. Although stress-specific factors increase ATP demand for cellular growth under stressful conditions, increased ATP demand for cellular maintenance underpins a general stress response and is responsible for the onset of overflow metabolism.
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Affiliation(s)
- Petri-Jaan Lahtvee
- Department of Biology and Biological Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden Novo Nordisk Foundation Center for Biosustainability, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - Rahul Kumar
- Department of Biology and Biological Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - Björn M Hallström
- Science for Life Laboratory, Royal Institute of Technology, 171 21, Stockholm, Sweden
| | - Jens Nielsen
- Department of Biology and Biological Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden Novo Nordisk Foundation Center for Biosustainability, Chalmers University of Technology, 412 96 Gothenburg, Sweden Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2970 Hørsholm, Denmark
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Thermotolerant yeasts selected by adaptive evolution express heat stress response at 30 °C. Sci Rep 2016; 6:27003. [PMID: 27229477 PMCID: PMC4882594 DOI: 10.1038/srep27003] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 05/12/2016] [Indexed: 11/10/2022] Open
Abstract
Exposure to long-term environmental changes across >100s of generations results in adapted phenotypes, but little is known about how metabolic and transcriptional responses are optimized in these processes. Here, we show that thermotolerant yeast strains selected by adaptive laboratory evolution to grow at increased temperature, activated a constitutive heat stress response when grown at the optimal ancestral temperature, and that this is associated with a reduced growth rate. This preventive response was perfected by additional transcriptional changes activated when the cultivation temperature is increased. Remarkably, the sum of global transcriptional changes activated in the thermotolerant strains when transferred from the optimal to the high temperature, corresponded, in magnitude and direction, to the global changes observed in the ancestral strain exposed to the same transition. This demonstrates robustness of the yeast transcriptional program when exposed to heat, and that the thermotolerant strains streamlined their path to rapidly and optimally reach post-stress transcriptional and metabolic levels. Thus, long-term adaptation to heat improved yeasts ability to rapidly adapt to increased temperatures, but this also causes a trade-off in the growth rate at the optimal ancestral temperature.
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Caspeta L, Castillo T, Nielsen J. Modifying Yeast Tolerance to Inhibitory Conditions of Ethanol Production Processes. Front Bioeng Biotechnol 2015; 3:184. [PMID: 26618154 PMCID: PMC4641163 DOI: 10.3389/fbioe.2015.00184] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2015] [Accepted: 10/28/2015] [Indexed: 11/17/2022] Open
Abstract
Saccharomyces cerevisiae strains having a broad range of substrate utilization, rapid substrate consumption, and conversion to ethanol, as well as good tolerance to inhibitory conditions are ideal for cost-competitive ethanol production from lignocellulose. A major drawback to directly design S. cerevisiae tolerance to inhibitory conditions of lignocellulosic ethanol production processes is the lack of knowledge about basic aspects of its cellular signaling network in response to stress. Here, we highlight the inhibitory conditions found in ethanol production processes, the targeted cellular functions, the key contributions of integrated -omics analysis to reveal cellular stress responses according to these inhibitors, and current status on design-based engineering of tolerant and efficient S. cerevisiae strains for ethanol production from lignocellulose.
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Affiliation(s)
- Luis Caspeta
- Centro de Investigación en Biotecnología, Universidad Autónoma del Estado de Morelos , Cuernavaca , Mexico
| | - Tania Castillo
- Centro de Investigación en Biotecnología, Universidad Autónoma del Estado de Morelos , Cuernavaca , Mexico
| | - Jens Nielsen
- Novo Nordisk Foundation Center for Biosustainability, Chalmers University of Technology , Gothenburg , Sweden ; Department of Biology and Biological Engineering, Chalmers University of Technology , Gothenburg , Sweden ; Novo Nordisk Foundation Center for Biosustainability , Hørsholm , Denmark
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Schulte PM. The effects of temperature on aerobic metabolism: towards a mechanistic understanding of the responses of ectotherms to a changing environment. J Exp Biol 2015; 218:1856-66. [DOI: 10.1242/jeb.118851] [Citation(s) in RCA: 387] [Impact Index Per Article: 43.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
ABSTRACT
Because of its profound effects on the rates of biological processes such as aerobic metabolism, environmental temperature plays an important role in shaping the distribution and abundance of species. As temperature increases, the rate of metabolism increases and then rapidly declines at higher temperatures – a response that can be described using a thermal performance curve (TPC). Although the shape of the TPC for aerobic metabolism is often attributed to the competing effects of thermodynamics, which can be described using the Arrhenius equation, and the effects of temperature on protein stability, this account represents an over-simplification of the factors acting even at the level of single proteins. In addition, it cannot adequately account for the effects of temperature on complex multistep processes, such as aerobic metabolism, that rely on mechanisms acting across multiple levels of biological organization. The purpose of this review is to explore our current understanding of the factors that shape the TPC for aerobic metabolism in response to acute changes in temperature, and to highlight areas where this understanding is weak or insufficient. Developing a more strongly grounded mechanistic model to account for the shape of the TPC for aerobic metabolism is crucial because these TPCs are the foundation of several recent attempts to predict the responses of species to climate change, including the metabolic theory of ecology and the hypothesis of oxygen and capacity-limited thermal tolerance.
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Liu Y, Zhang G, Sun H, Sun X, Jiang N, Rasool A, Lin Z, Li C. Enhanced pathway efficiency of Saccharomyces cerevisiae by introducing thermo-tolerant devices. BIORESOURCE TECHNOLOGY 2014; 170:38-44. [PMID: 25118151 DOI: 10.1016/j.biortech.2014.07.063] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 07/15/2014] [Accepted: 07/16/2014] [Indexed: 06/03/2023]
Abstract
In this study, thermo-tolerant devices consisting of heat shock genes from thermophiles were designed and introduced into Saccharomyces cerevisiae for improving its thermo-tolerance. Among ten engineered thermo-tolerant yeasts, T.te-TTE2469, T.te-GroS2 and T.te-IbpA displayed over 25% increased cell density and 1.5-4-fold cell viability compared with the control. Physiological characteristics of thermo-tolerant strains revealed that better cell wall integrity, higher trehalose content and enhanced metabolic energy were preserved by thermo-tolerant devices. Engineered thermo-tolerant strain was used to investigate the impact of thermo-tolerant device on pathway efficiency by introducing β-amyrin synthesis pathway, showed 28.1% increased β-amyrin titer, 28-35°C broadened growth temperature range and 72h shortened fermentation period. The results indicated that implanting heat shock proteins from thermophiles to S. cerevisiae would be an efficient approach to improve its thermo-tolerance.
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Affiliation(s)
- Yueqin Liu
- School of Chemical Engineering, Tianjin University, Tianjin 300072, China
| | - Genli Zhang
- School of Life Science, Beijing Institute of Technology, Beijing 100081, China
| | - Huan Sun
- School of Life Science, Beijing Institute of Technology, Beijing 100081, China
| | - Xiangying Sun
- School of Life Science, Beijing Institute of Technology, Beijing 100081, China
| | - Nisi Jiang
- School of Life Science, Beijing Institute of Technology, Beijing 100081, China
| | - Aamir Rasool
- School of Life Science, Beijing Institute of Technology, Beijing 100081, China
| | | | - Chun Li
- School of Chemical Engineering, Tianjin University, Tianjin 300072, China; School of Life Science, Beijing Institute of Technology, Beijing 100081, China.
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Chen Y, Liu Q, Chen X, Wu J, Xie J, Guo T, Zhu C, Ying H. Control of glycolytic flux in directed biosynthesis of uridine-phosphoryl compounds through the manipulation of ATP availability. Appl Microbiol Biotechnol 2014; 98:6621-32. [PMID: 24769901 DOI: 10.1007/s00253-014-5701-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Revised: 02/14/2014] [Accepted: 03/17/2014] [Indexed: 11/24/2022]
Abstract
Adenosine triphosphate (ATP), the most important energy source for metabolic reactions and pathways, plays a vital role in control of metabolic flux. Considering the importance of ATP in regulation of the glycolytic pathway, the use of ATP-oriented manipulation is a rational and efficient route to regulate metabolic flux. In this paper, a series of efficient ATP-oriented regulation methods, such as changing ambient temperature and altering reduced nicotinamide adenine dinucleotide (NADH), was developed. To satisfy the different demand for ATP at different phases in directed biosynthesis of uridine-phosphoryl compounds, a multiphase ATP supply regulation strategy was also used to enhance to yield of target metabolites.
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Affiliation(s)
- Yong Chen
- College of Biotechnology and Pharmaceutical Engineering, Nanjing University of Technology, Xin mofan Road 5, Nanjing, 210009, China
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Spatial reorganization of Saccharomyces cerevisiae enolase to alter carbon metabolism under hypoxia. EUKARYOTIC CELL 2013; 12:1106-19. [PMID: 23748432 DOI: 10.1128/ec.00093-13] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Hypoxia has critical effects on the physiology of organisms. In the yeast Saccharomyces cerevisiae, glycolytic enzymes, including enolase (Eno2p), formed cellular foci under hypoxia. Here, we investigated the regulation and biological functions of these foci. Focus formation by Eno2p was inhibited temperature independently by the addition of cycloheximide or rapamycin or by the single substitution of alanine for the Val22 residue. Using mitochondrial inhibitors and an antioxidant, mitochondrial reactive oxygen species (ROS) production was shown to participate in focus formation. Focus formation was also inhibited temperature dependently by an SNF1 knockout mutation. Interestingly, the foci were observed in the cell even after reoxygenation. The metabolic turnover analysis revealed that [U-(13)C]glucose conversion to pyruvate and oxaloacetate was accelerated in focus-forming cells. These results suggest that under hypoxia, S. cerevisiae cells sense mitochondrial ROS and, by the involvement of SNF1/AMPK, spatially reorganize metabolic enzymes in the cytosol via de novo protein synthesis, which subsequently increases carbon metabolism. The mechanism may be important for yeast cells under hypoxia, to quickly provide both energy and substrates for the biosynthesis of lipids and proteins independently of the tricarboxylic acid (TCA) cycle and also to fit changing environments.
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