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He M, Guo R, Chen G, Xiong C, Yang X, Wei Y, Chen Y, Qiu J, Zhang Q. Comprehensive Response of Rhodosporidium kratochvilovae to Glucose Starvation: A Transcriptomics-Based Analysis. Microorganisms 2023; 11:2168. [PMID: 37764012 PMCID: PMC10534369 DOI: 10.3390/microorganisms11092168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 08/17/2023] [Accepted: 08/24/2023] [Indexed: 09/29/2023] Open
Abstract
Microorganisms adopt diverse mechanisms to adapt to fluctuations of nutrients. Glucose is the preferred carbon and energy source for yeast. Yeast cells have developed many strategies to protect themselves from the negative impact of glucose starvation. Studies have indicated a significant increase of carotenoids in red yeast under glucose starvation. However, their regulatory mechanism is still unclear. In this study, we investigated the regulatory mechanism of carotenoid biosynthesis in Rhodosporidium kratochvilovae YM25235 under glucose starvation. More intracellular reactive oxygen species (ROS) was produced when glucose was exhausted. Enzymatic and non-enzymatic (mainly carotenoids) antioxidant systems in YM25235 were induced to protect cells from ROS-related damage. Transcriptome analysis revealed massive gene expression rearrangement in YM25235 under glucose starvation, leading to alterations in alternative carbon metabolic pathways. Some potential pathways for acetyl-CoA and then carotenoid biosynthesis, including fatty acid β-oxidation, amino acid metabolism, and pyruvate metabolism, were significantly enriched in KEGG analysis. Overexpression of the fatty acyl-CoA oxidase gene (RkACOX2), the first key rate-limiting enzyme of peroxisomal fatty acid β-oxidation, demonstrated that fatty acid β-oxidation could increase the acetyl-CoA and carotenoid concentration in YM25235. These findings contribute to a better understanding of the overall response of red yeast to glucose starvation and the regulatory mechanisms governing carotenoid biosynthesis under glucose starvation.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Qi Zhang
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming 650500, China; (M.H.); (R.G.); (G.C.); (C.X.); (X.Y.); (Y.W.); (Y.C.); (J.Q.)
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2
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Weber CA, Sekar K, Tang JH, Warmer P, Sauer U, Weis K. β-Oxidation and autophagy are critical energy providers during acute glucose depletion in S accharomyces cerevisiae. Proc Natl Acad Sci U S A 2020; 117:12239-12248. [PMID: 32430326 PMCID: PMC7275744 DOI: 10.1073/pnas.1913370117] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The ability to tolerate and thrive in diverse environments is paramount to all living organisms, and many organisms spend a large part of their lifetime in starvation. Upon acute glucose starvation, yeast cells undergo drastic physiological and metabolic changes and reestablish a constant-although lower-level of energy production within minutes. The molecules that are rapidly metabolized to fuel energy production under these conditions are unknown. Here, we combine metabolomics and genetics to characterize the cells' response to acute glucose depletion and identify pathways that ensure survival during starvation. We show that the ability to respire is essential for maintaining the energy status and to ensure viability during starvation. Measuring the cells' immediate metabolic response, we find that central metabolites drastically deplete and that the intracellular AMP-to-ATP ratio strongly increases within 20 to 30 s. Furthermore, we detect changes in both amino acid and lipid metabolite levels. Consistent with this, both bulk autophagy, a process that frees amino acids, and lipid degradation via β-oxidation contribute in parallel to energy maintenance upon acute starvation. In addition, both these pathways ensure long-term survival during starvation. Thus, our results identify bulk autophagy and β-oxidation as important energy providers during acute glucose starvation.
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Affiliation(s)
- Carmen A Weber
- Department of Biology, Institute of Biochemistry, ETH (Eidgenössische Technische Hochschule) Zurich, 8093 Zurich, Switzerland
| | - Karthik Sekar
- Department of Biology, Institute of Molecular Systems Biology, ETH Zurich, 8093 Zurich, Switzerland
| | - Jeffrey H Tang
- Department of Biology, Institute of Biochemistry, ETH (Eidgenössische Technische Hochschule) Zurich, 8093 Zurich, Switzerland
| | - Philipp Warmer
- Department of Biology, Institute of Molecular Systems Biology, ETH Zurich, 8093 Zurich, Switzerland
| | - Uwe Sauer
- Department of Biology, Institute of Molecular Systems Biology, ETH Zurich, 8093 Zurich, Switzerland
| | - Karsten Weis
- Department of Biology, Institute of Biochemistry, ETH (Eidgenössische Technische Hochschule) Zurich, 8093 Zurich, Switzerland;
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Pang Y, Zhao Y, Li S, Zhao Y, Li J, Hu Z, Zhang C, Xiao D, Yu A. Engineering the oleaginous yeast Yarrowia lipolytica to produce limonene from waste cooking oil. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:241. [PMID: 31624503 PMCID: PMC6781337 DOI: 10.1186/s13068-019-1580-y] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 09/25/2019] [Indexed: 05/24/2023]
Abstract
BACKGROUND Limonene is an important biologically active natural product widely used in the food, cosmetic, nutraceutical and pharmaceutical industries. However, the low abundance of limonene in plants renders their isolation from plant sources non-economically viable. Therefore, engineering microbes into microbial factories for producing limonene is fast becoming an attractive alternative approach that can overcome the aforementioned bottleneck to meet the needs of industries and make limonene production more sustainable and environmentally friendly. RESULTS In this proof-of-principle study, the oleaginous yeast Yarrowia lipolytica was successfully engineered to produce both d-limonene and l-limonene by introducing the heterologous d-limonene synthase from Citrus limon and l-limonene synthase from Mentha spicata, respectively. However, only 0.124 mg/L d-limonene and 0.126 mg/L l-limonene were produced. To improve the limonene production by the engineered yeast Y. lipolytica strain, ten genes involved in the mevalonate-dependent isoprenoid pathway were overexpressed individually to investigate their effects on limonene titer. Hydroxymethylglutaryl-CoA reductase (HMGR) was found to be the key rate-limiting enzyme in the mevalonate (MVA) pathway for the improving limonene synthesis in Y. lipolytica. Through the overexpression of HMGR gene, the titers of d-limonene and l-limonene were increased to 0.256 mg/L and 0.316 mg/L, respectively. Subsequently, the fermentation conditions were optimized to maximize limonene production by the engineered Y. lipolytica strains from glucose, and the final titers of d-limonene and l-limonene were improved to 2.369 mg/L and 2.471 mg/L, respectively. Furthermore, fed-batch fermentation of the engineered strains Po1g KdHR and Po1g KlHR was used to enhance limonene production in shake flasks and the titers achieved for d-limonene and l-limonene were 11.705 mg/L (0.443 mg/g) and 11.088 mg/L (0.385 mg/g), respectively. Finally, the potential of using waste cooking oil as a carbon source for limonene biosynthesis from the engineered Y. lipolytica strains was investigated. We showed that d-limonene and l-limonene were successfully produced at the respective titers of 2.514 mg/L and 2.723 mg/L under the optimal cultivation condition, where 70% of waste cooking oil was added as the carbon source, representing a 20-fold increase in limonene titer compared to that before strain and fermentation optimization. CONCLUSIONS This study represents the first report on the development of a new and efficient process to convert waste cooking oil into d-limonene and l-limonene by exploiting metabolically engineered Y. lipolytica strains for fermentation. The results obtained in this study lay the foundation for more future applications of Y. lipolytica in converting waste cooking oil into various industrially valuable products.
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Affiliation(s)
- Yaru Pang
- State Key Laboratory of Food Nutrition and Safety, Key Laboratory of Industrial Fermentation Microbiology of the Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, Tianjin Engineering Research Center of Microbial Metabolism and Fermentation Process Control, College of Biotechnology, Tianjin University of Science and Technology, No.29 the 13th Street TEDA, Tianjin, 300457 People’s Republic of China
| | - Yakun Zhao
- State Key Laboratory of Food Nutrition and Safety, Key Laboratory of Industrial Fermentation Microbiology of the Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, Tianjin Engineering Research Center of Microbial Metabolism and Fermentation Process Control, College of Biotechnology, Tianjin University of Science and Technology, No.29 the 13th Street TEDA, Tianjin, 300457 People’s Republic of China
| | - Shenglong Li
- State Key Laboratory of Food Nutrition and Safety, Key Laboratory of Industrial Fermentation Microbiology of the Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, Tianjin Engineering Research Center of Microbial Metabolism and Fermentation Process Control, College of Biotechnology, Tianjin University of Science and Technology, No.29 the 13th Street TEDA, Tianjin, 300457 People’s Republic of China
| | - Yu Zhao
- State Key Laboratory of Food Nutrition and Safety, Key Laboratory of Industrial Fermentation Microbiology of the Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, Tianjin Engineering Research Center of Microbial Metabolism and Fermentation Process Control, College of Biotechnology, Tianjin University of Science and Technology, No.29 the 13th Street TEDA, Tianjin, 300457 People’s Republic of China
| | - Jian Li
- State Key Laboratory of Food Nutrition and Safety, Key Laboratory of Industrial Fermentation Microbiology of the Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, Tianjin Engineering Research Center of Microbial Metabolism and Fermentation Process Control, College of Biotechnology, Tianjin University of Science and Technology, No.29 the 13th Street TEDA, Tianjin, 300457 People’s Republic of China
| | - Zhihui Hu
- State Key Laboratory of Food Nutrition and Safety, Key Laboratory of Industrial Fermentation Microbiology of the Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, Tianjin Engineering Research Center of Microbial Metabolism and Fermentation Process Control, College of Biotechnology, Tianjin University of Science and Technology, No.29 the 13th Street TEDA, Tianjin, 300457 People’s Republic of China
| | - Cuiying Zhang
- State Key Laboratory of Food Nutrition and Safety, Key Laboratory of Industrial Fermentation Microbiology of the Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, Tianjin Engineering Research Center of Microbial Metabolism and Fermentation Process Control, College of Biotechnology, Tianjin University of Science and Technology, No.29 the 13th Street TEDA, Tianjin, 300457 People’s Republic of China
| | - Dongguang Xiao
- State Key Laboratory of Food Nutrition and Safety, Key Laboratory of Industrial Fermentation Microbiology of the Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, Tianjin Engineering Research Center of Microbial Metabolism and Fermentation Process Control, College of Biotechnology, Tianjin University of Science and Technology, No.29 the 13th Street TEDA, Tianjin, 300457 People’s Republic of China
| | - Aiqun Yu
- State Key Laboratory of Food Nutrition and Safety, Key Laboratory of Industrial Fermentation Microbiology of the Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, Tianjin Engineering Research Center of Microbial Metabolism and Fermentation Process Control, College of Biotechnology, Tianjin University of Science and Technology, No.29 the 13th Street TEDA, Tianjin, 300457 People’s Republic of China
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Parveen M, Miyagi A, Kawai-Yamada M, Rashid MH, Asaeda T. Metabolic and biochemical responses of Potamogeton anguillanus Koidz. (Potamogetonaceae) to low oxygen conditions. JOURNAL OF PLANT PHYSIOLOGY 2019; 232:171-179. [PMID: 30537604 DOI: 10.1016/j.jplph.2018.11.023] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 02/21/2018] [Accepted: 11/19/2018] [Indexed: 06/09/2023]
Abstract
Oxygen availability in water is considered one of the most important factors for growth and productivity in aquatic submerged macrophytes. In the present study, the growth, stress responses, and metabolic changes in Potamogeton anguillanus Koidz. (Potamogetonaceae) were assessed after a 21-day exposure to low (hypoxia; dissolved oxygen, DO < 1 mg/L) or null (anoxia) oxygen concentrations in water. High growth rates and an increased indole acetic acid (IAA) content in P. anguillanus were observed under the hypoxic conditions (4-fold to control) compared to the anoxic conditions. In addition, the activation of glycolysis and fermentation processes was further recorded, given the increase in alcohol dehydrogenase activity and pyruvate concentration on the studied plants that were exposed to low oxygen concentrations. Moreover, the positive correlations of antioxidative enzyme activities, catalase (CAT) and guaiacol peroxidase (POD) with hydrogen peroxide (H2O2) confirmed the species ability to scavenge excess H2O2 under low oxygen stress. The capillary electrophoresis-mass spectrometry (CE-MS) analysis of the metabolome identified metabolite accumulations (e.g., glutamate, glutamine, aspartate, asparagine, valine, malate, lactate, citrate, isocitrate, proline and γ-amino butyric acid) in response to the anoxia.
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Affiliation(s)
- Mahfuza Parveen
- Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama 338-8570, Japan; Department of Environmental Science and Disaster Management, Daffodil International University, Bangladesh.
| | - Atsuko Miyagi
- Department of Environmental Science and Technology, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama 338-8570, Japan.
| | - Maki Kawai-Yamada
- Department of Environmental Science and Technology, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama 338-8570, Japan.
| | - Md H Rashid
- Department of Environmental Science and Technology, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama 338-8570, Japan; Bangladesh Agricultural University, Mymensingh-2202, Bangladesh.
| | - Takashi Asaeda
- Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama 338-8570, Japan; Research Institute of Chuo University, Kasuga, Bunkyo, Tokyo 112-8551, Japan.
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5
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Bajerski F, Stock J, Hanf B, Darienko T, Heine-Dobbernack E, Lorenz M, Naujox L, Keller ERJ, Schumacher HM, Friedl T, Eberth S, Mock HP, Kniemeyer O, Overmann J. ATP Content and Cell Viability as Indicators for Cryostress Across the Diversity of Life. Front Physiol 2018; 9:921. [PMID: 30065659 PMCID: PMC6056685 DOI: 10.3389/fphys.2018.00921] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Accepted: 06/25/2018] [Indexed: 11/30/2022] Open
Abstract
In many natural environments, organisms get exposed to low temperature and/or to strong temperature shifts. Also, standard preservation protocols for live cells or tissues involve ultradeep freezing in or above liquid nitrogen (-196°C or -150°C, respectively). To which extent these conditions cause cold- or cryostress has rarely been investigated systematically. Using ATP content as an indicator of the physiological state of cells, we found that representatives of bacteria, fungi, algae, plant tissue, as well as plant and human cell lines exhibited similar responses during freezing and thawing. Compared to optimum growth conditions, the cellular ATP content of most model organisms decreased significantly upon treatment with cryoprotectant and cooling to up to -196°C. After thawing and a longer period of regeneration, the initial ATP content was restored or even exceeded the initial ATP levels. To assess the implications of cellular ATP concentration for the physiology of cryostress, cell viability was determined in parallel using independent approaches. A significantly positive correlation of ATP content and viability was detected only in the cryosensitive algae Chlamydomonas reinhardtii SAG 11-32b and Chlorella variabilis NC64A, and in plant cell lines of Solanum tuberosum. When comparing mesophilic with psychrophilic bacteria of the same genera, and cryosensitive with cryotolerant algae, ATP levels of actively growing cells were generally higher in the psychrophilic and cryotolerant representatives. During exposure to ultralow temperatures, however, psychrophilic and cryotolerant species showed a decline in ATP content similar to their mesophilic or cryosensitive counterparts. Nevertheless, psychrophilic and cryotolerant species attained better culturability after freezing. Cellular ATP concentrations and viability measurements thus monitor different features of live cells during their exposure to ultralow temperatures and cryostress.
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Affiliation(s)
- Felizitas Bajerski
- Leibniz Institute DSMZ - German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Johanna Stock
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany
| | - Benjamin Hanf
- Leibniz Institute for Natural Product Research and Infection Biology e.V. - Hans-Knöll-Institute (HKI), Jena, Germany.,Institute of Microbiology, Friedrich Schiller University Jena, Jena, Germany
| | - Tatyana Darienko
- Experimental Phycology and Culture Collection of Algae, University of Göttingen (EPSAG), Göttingen, Germany
| | - Elke Heine-Dobbernack
- Leibniz Institute DSMZ - German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Maike Lorenz
- Experimental Phycology and Culture Collection of Algae, University of Göttingen (EPSAG), Göttingen, Germany
| | - Lisa Naujox
- Leibniz Institute DSMZ - German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - E R J Keller
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany
| | - H M Schumacher
- Leibniz Institute DSMZ - German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Thomas Friedl
- Experimental Phycology and Culture Collection of Algae, University of Göttingen (EPSAG), Göttingen, Germany
| | - Sonja Eberth
- Leibniz Institute DSMZ - German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Hans-Peter Mock
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany
| | - Olaf Kniemeyer
- Leibniz Institute for Natural Product Research and Infection Biology e.V. - Hans-Knöll-Institute (HKI), Jena, Germany.,Institute of Microbiology, Friedrich Schiller University Jena, Jena, Germany
| | - Jörg Overmann
- Leibniz Institute DSMZ - German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
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6
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Hou L, Liu L, Zhang H, Zhang L, Zhang L, Zhang J, Gao Q, Wang D. Functional analysis of the mitochondrial alternative oxidase gene (aox1) from Aspergillus niger CGMCC 10142 and its effects on citric acid production. Appl Microbiol Biotechnol 2018; 102:7981-7995. [DOI: 10.1007/s00253-018-9197-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 05/10/2018] [Accepted: 05/14/2018] [Indexed: 11/28/2022]
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7
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Improving total glutathione and trehalose contents in Saccharomyces cerevisiae cells to enhance their resistance to fluidized bed drying. Process Biochem 2018. [DOI: 10.1016/j.procbio.2018.03.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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8
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Nemec AA, Howell LA, Peterson AK, Murray MA, Tomko RJ. Autophagic clearance of proteasomes in yeast requires the conserved sorting nexin Snx4. J Biol Chem 2017; 292:21466-21480. [PMID: 29109144 DOI: 10.1074/jbc.m117.817999] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 11/03/2017] [Indexed: 11/06/2022] Open
Abstract
Turnover of the 26S proteasome by autophagy is an evolutionarily conserved process that governs cellular proteolytic capacity and eliminates inactive particles. In most organisms, proteasomes are located in both the nucleus and cytoplasm. However, the specific autophagy routes for nuclear and cytoplasmic proteasomes are unclear. Here, we investigate the spatial control of autophagic proteasome turnover in budding yeast (Saccharomyces cerevisiae). We found that nitrogen starvation-induced proteasome autophagy is independent of known nucleophagy pathways but is compromised when nuclear protein export is blocked. Furthermore, via pharmacological tethering of proteasomes to chromatin or the plasma membrane, we provide evidence that nuclear proteasomes at least partially disassemble before autophagic turnover, whereas cytoplasmic proteasomes remain largely intact. A targeted screen of autophagy genes identified a requirement for the conserved sorting nexin Snx4 in the autophagic turnover of proteasomes and several other large multisubunit complexes. We demonstrate that Snx4 cooperates with sorting nexins Snx41 and Snx42 to mediate proteasome turnover and is required for the formation of cytoplasmic proteasome puncta that accumulate when autophagosome formation is blocked. Together, our results support distinct mechanistic paths in the turnover of nuclear versus cytoplasmic proteasomes and point to a critical role for Snx4 in cytoplasmic agglomeration of proteasomes en route to autophagic destruction.
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Affiliation(s)
- Antonia A Nemec
- From the Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida 32306
| | - Lauren A Howell
- From the Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida 32306
| | - Anna K Peterson
- From the Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida 32306
| | - Matthew A Murray
- From the Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida 32306
| | - Robert J Tomko
- From the Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida 32306
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9
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Cellobiose Consumption Uncouples Extracellular Glucose Sensing and Glucose Metabolism in Saccharomyces cerevisiae. mBio 2017; 8:mBio.00855-17. [PMID: 28790206 PMCID: PMC5550752 DOI: 10.1128/mbio.00855-17] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Glycolysis is central to energy metabolism in most organisms and is highly regulated to enable optimal growth. In the yeast Saccharomyces cerevisiae, feedback mechanisms that control flux through glycolysis span transcriptional control to metabolite levels in the cell. Using a cellobiose consumption pathway, we decoupled glucose sensing from carbon utilization, revealing new modular layers of control that induce ATP consumption to drive rapid carbon fermentation. Alterations of the beta subunit of phosphofructokinase-1 (PFK2), H+-plasma membrane ATPase (PMA1), and glucose sensors (SNF3 and RGT2) revealed the importance of coupling extracellular glucose sensing to manage ATP levels in the cell. Controlling the upper bound of cellular ATP levels may be a general mechanism used to regulate energy levels in cells, via a regulatory network that can be uncoupled from ATP concentrations under perceived starvation conditions. Living cells are fine-tuned through evolution to thrive in their native environments. Genome alterations to create organisms for specific biotechnological applications may result in unexpected and undesired phenotypes. We used a minimal synthetic biological system in the yeast Saccharomyces cerevisiae as a platform to reveal novel connections between carbon sensing, starvation conditions, and energy homeostasis.
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10
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Bisschops MM, Vos T, Martínez-Moreno R, Cortés PT, Pronk JT, Daran-Lapujade P. Oxygen availability strongly affects chronological lifespan and thermotolerance in batch cultures of Saccharomyces cerevisiae. MICROBIAL CELL (GRAZ, AUSTRIA) 2015; 2:429-444. [PMID: 28357268 PMCID: PMC5349206 DOI: 10.15698/mic2015.11.238] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 09/13/2015] [Indexed: 01/08/2023]
Abstract
Stationary-phase (SP) batch cultures of Saccharomyces cerevisiae, in which growth has been arrested by carbon-source depletion, are widely applied to study chronological lifespan, quiescence and SP-associated robustness. Based on this type of experiments, typically performed under aerobic conditions, several roles of oxygen in aging have been proposed. However, SP in anaerobic yeast cultures has not been investigated in detail. Here, we use the unique capability of S. cerevisiae to grow in the complete absence of oxygen to directly compare SP in aerobic and anaerobic bioreactor cultures. This comparison revealed strong positive effects of oxygen availability on adenylate energy charge, longevity and thermotolerance during SP. A low thermotolerance of anaerobic batch cultures was already evident during the exponential growth phase and, in contrast to the situation in aerobic cultures, was not substantially increased during transition into SP. A combination of physiological and transcriptome analysis showed that the slow post-diauxic growth phase on ethanol, which precedes SP in aerobic, but not in anaerobic cultures, endowed cells with the time and resources needed for inducing longevity and thermotolerance. When combined with literature data on acquisition of longevity and thermotolerance in retentostat cultures, the present study indicates that the fast transition from glucose excess to SP in anaerobic cultures precludes acquisition of longevity and thermotolerance. Moreover, this study demonstrates the importance of a preceding, calorie-restricted conditioning phase in the acquisition of longevity and stress tolerance in SP yeast cultures, irrespective of oxygen availability.
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Affiliation(s)
- Markus M. Bisschops
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
- Current address: Division of Systems and Synthetic Biology, Department of Biology and Biological Engineering & The Novo Nordisk Foundation Center for Biosustainability, Chalmers University of Technology, Gothenburg, Sweden
| | - Tim Vos
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | - Rubén Martínez-Moreno
- Instituto de Ciencias de la Vid y del Vino, CSIC, Universidad de La Rioja, Gobierno de La Rioja, Logroño, Spain
- Current address: Quercus Europe S.L., L’Hospitalet de Llobregat, Catalonia, Spain
| | - Pilar T. Cortés
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | - Jack T. Pronk
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
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11
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Lew LC, Liong MT, Gan CY. Growth optimization of Lactobacillus rhamnosus
FTDC 8313 and the production of putative dermal bioactives in the presence of manganese and magnesium ions. J Appl Microbiol 2012; 114:526-35. [DOI: 10.1111/jam.12044] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Revised: 10/04/2012] [Accepted: 10/15/2012] [Indexed: 11/30/2022]
Affiliation(s)
- L.-C. Lew
- School of Industrial Technology; UniversitiSains Malaysia; Penang 11800 USM Malaysia
| | - M.-T. Liong
- School of Industrial Technology; UniversitiSains Malaysia; Penang 11800 USM Malaysia
| | - C.-Y. Gan
- Doping Control Centre; UniversitiSains Malaysia; Penang 11800 USM Malaysia
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12
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Ylitervo P, Franzén CJ, Taherzadeh MJ. Ethanol production at elevated temperatures using encapsulation of yeast. J Biotechnol 2011; 156:22-9. [PMID: 21807041 DOI: 10.1016/j.jbiotec.2011.07.018] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Revised: 06/30/2011] [Accepted: 07/12/2011] [Indexed: 10/18/2022]
Abstract
The ability of macroencapsulated Saccharomyces cerevisiae CBS 8066 to produce ethanol at elevated temperatures was investigated in consecutive batch and continuous cultures. Prior to cultivation yeast was confined inside alginate-chitosan capsules composed of an outer semi-permeable membrane and an inner liquid core. The encapsulated yeast could successfully ferment 30 g/L glucose and produce ethanol at a high yield in five consecutive batches of 12 h duration at 42°C, while freely suspended yeast was completely inactive already in the third batch. A high ethanol production was observed also through the first 48 h at 40°C during continuous cultivation at D=0.2 h(-1) when using encapsulated cells. The ethanol production slowly decreased in the following days at 40°C. The ethanol production was also measured in a continuous cultivation in which the temperature was periodically increased to 42-45°C and lowered to 37°C again in periods of 12h. Our investigation shows that a non-thermotolerant yeast strain improved its heat tolerance upon encapsulation, and could produce ethanol at temperatures as high as 45°C for a short time. The possibility of performing fermentations at higher temperatures would greatly improve the enzymatic hydrolysis in simultaneous saccharification and fermentation (SSF) processes and thereby make the bioethanol production process more economically feasible.
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Affiliation(s)
- Päivi Ylitervo
- School of Engineering, University of Borås, 501 90 Borås, Sweden.
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13
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Influence of cultivation procedure for Saccharomyces cerevisiae used as pitching agent in industrial spent sulphite liquor fermentations. J Ind Microbiol Biotechnol 2011; 38:1787-92. [PMID: 21505915 DOI: 10.1007/s10295-011-0965-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Accepted: 03/16/2011] [Indexed: 10/18/2022]
Abstract
The cell viability and fermentation performance often deteriorate in fermentations of spent sulphite liquor (SSL). This investigation therefore addresses the question of how different cultivation conditions for yeast cells influence their ability to survive and boost the ethanol production capacity in an SSL-based fermentation process. The strains used as pitching agents were an industrially harvested Saccharomyces cerevisiae and commercial dry baker's yeast. This study therefore suggests that exposure to SSL in combination with nutrients, prior to the fermentation step, is crucial for the performance of the yeast. Supplying 0.5 g/l fresh yeast cultivated under appropriate cultivation conditions may increase ethanol concentration more than 200%.
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Yoon J, Chang ST, Park JS, Kim YH, Min J. Functional characterization of starvation-induced lysosomal activity in Saccharomyces cerevisiae. Appl Microbiol Biotechnol 2010; 88:283-9. [PMID: 20632003 DOI: 10.1007/s00253-010-2755-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2010] [Revised: 06/27/2010] [Accepted: 06/29/2010] [Indexed: 01/18/2023]
Abstract
Starvation induces significant alterations in lysosomal enzymes, and reduced concentrations of glucose increases the activity of several lysosomal enzymes. Therefore, to evaluate the lysosomal antimicrobial activity under starvation conditions, we added 0, 5, 10, 20, or 40 g/l of glucose (0%, 0.5%, 1%, 2%, or 4% glucose) supplemented YP medium to cultured Saccharomyces cerevisiae, and lysosomal fractions were isolated from S. cerevisiae grown under the various culture conditions. The lysosomes isolated from each condition exhibited increased antimicrobial activity against Escherichia coli as determined by a decrease in glucose concentration. In addition, a starvation-dependent increase in lysosomal activity coincided with increased lysosome intensity at the cytosol and distinct protein expression from lysosomes in S. cerevisiae. It also was determined found that the lysosomes have antimicrobial activity against seven different microorganisms, including E. coli, and starvation-induced lysosomes showed enhanced antimicrobial activity compared to those from normal lysosomes. These results suggest the possibility that lysosomal alterations during starvation may induce conditions that activate lysosomes for future development of efficient antimicrobial agents.
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Affiliation(s)
- Jihee Yoon
- Graduate School of Semiconductor and Chemical Engineering, Chonbuk National University, 664-14 Duckjin-dong, Jeonju, 561-756, South Korea
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15
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Saavedra E, Ramos-Casillas LE, MarÃn-Hernández A, Moreno-Sánchez R, Guerra-Sánchez G. Glycolysis inUstilago maydis. FEMS Yeast Res 2008; 8:1313-23. [DOI: 10.1111/j.1567-1364.2008.00437.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Brandberg T, Sanandaji N, Gustafsson L, Franzén CJ. Continuous Fermentation of Undetoxified Dilute Acid Lignocellulose Hydrolysate by Saccharomycescerevisiae ATCC 96581 Using Cell Recirculation. Biotechnol Prog 2008; 21:1093-101. [PMID: 16080688 DOI: 10.1021/bp050006y] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Saccharomyces cerevisiae ATCC 96581 was cultivated in a chemostat reactor with undetoxified dilute acid softwood hydrolysate as the only carbon and energy source. The effects of nutrient addition, dilution rate, cell recirculation, and microaerobicity were investigated. Fermentation of unsupplemented dilute acid lignocellulose hydrolysate at D = 0.10 h(-1) in an anaerobic continuous reactor led to washout. Addition of ammonium sulfate or yeast extract was insufficient for obtaining steady state. In contrast, dilute acid lignocellulose hydrolysate supplemented with complete mineral medium, except for the carbon and energy source, was fermentable under anaerobic steady-state conditions at dilution rates up to 0.14 h(-1). Under these conditions, washout occurred at D = 0.15 h(-1). This was preceded by a drop in fermentative capacity and a very high specific ethanol production rate. Growth at all different dilution rates tested resulted in residual sugar in the chemostat. Cell recirculation (90%), achieved by cross-flow filtration, increased the sugar conversion rate from 92% to 99% at D = 0.10 h(-1). Nutrient addition clearly improved the long-term ethanol productivity in the recirculation cultures. Application of microaerobic conditions on the nutrient-supplemented recirculation cultures resulted in a higher production of biomass, a higher cellular protein content, and improved fermentative capacity, which further improves the robustness of fermentation of undetoxified lignocellulose hydrolysate.
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Affiliation(s)
- Tomas Brandberg
- Department of Chemical and Biological Engineering, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
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17
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Zamani J, Pournia P, Seirafi H. A novel feeding method in commercial Baker’s yeast production. J Appl Microbiol 2008; 105:674-80. [DOI: 10.1111/j.1365-2672.2008.03781.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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18
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Cotter JL, Chinn MS, Grunden AM. Ethanol and acetate production by Clostridium ljungdahlii and Clostridium autoethanogenum using resting cells. Bioprocess Biosyst Eng 2008; 32:369-80. [DOI: 10.1007/s00449-008-0256-y] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2008] [Accepted: 08/06/2008] [Indexed: 11/29/2022]
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19
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The effects of elevated process temperature on the protein carbonyls in the filamentous fungus, Aspergillus niger B1-D. Process Biochem 2008. [DOI: 10.1016/j.procbio.2008.04.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Manariotis ID, Grigoropoulos SG. Restart of anaerobic filters treating low-strength wastewater. BIORESOURCE TECHNOLOGY 2008; 99:3579-89. [PMID: 17855084 DOI: 10.1016/j.biortech.2007.07.048] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2007] [Revised: 07/23/2007] [Accepted: 07/27/2007] [Indexed: 05/17/2023]
Abstract
The anaerobic filter (AF) technology offers an alternative method for the direct treatment of low-strength wastewater and the study was undertaken to access AF-biomass reactivation after prolonged nonfeeding periods, an important characteristic making the process suitable for handling variable or intermittent pollution loads. Four upflow AF (three 12.5-L and one 3.9-L, each with different packing), which had treated municipal-type wastewaters (natural, amended or synthetic) for 34 months at 25 or 16 degrees C and varying hydraulic loads and had remained inactive for 24 months, were used. All units were fed synthetic wastewater [mean chemical oxygen demand (COD) 323 mg/L, total suspended solids (TSS) 47 mg/L] and operated at 27 degrees C for 2.5 months (phase 1); and following a 6-month idle period, the smaller filter treated municipal wastewater (mean COD and TSS 820 and 448 mg/L) at 16 degrees C for an additional 2.5 months (phase 2). The larger units operated at a 2.0-d hydraulic retention time and the smaller at 1.0-0.33-d in phase 1 and 2.0 or 1.0-d in phase 2. Reactivation was quick and yielded efficient treatment. Restart was affected by the AF history and packing morphology, the types of wastewater previously handled, and the duration of the nonfeeding period.
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Affiliation(s)
- Ioannis D Manariotis
- Department of Civil Engineering, University of Patras, GR-265 00 Patras, Greece.
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21
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Li Q, Harvey LM, McNeil B. Oxygen enrichment effects on protein oxidation, proteolytic activity and the energy status of submerged batch cultures of Aspergillus niger B1-D. Process Biochem 2008. [DOI: 10.1016/j.procbio.2007.11.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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New insights into the Saccharomyces cerevisiae fermentation switch: dynamic transcriptional response to anaerobicity and glucose-excess. BMC Genomics 2008; 9:100. [PMID: 18304306 PMCID: PMC2292174 DOI: 10.1186/1471-2164-9-100] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2007] [Accepted: 02/27/2008] [Indexed: 01/13/2023] Open
Abstract
Background The capacity of respiring cultures of Saccharomyces cerevisiae to immediately switch to fast alcoholic fermentation upon a transfer to anaerobic sugar-excess conditions is a key characteristic of Saccharomyces cerevisiae in many of its industrial applications. This transition was studied by exposing aerobic glucose-limited chemostat cultures grown at a low specific growth rate to two simultaneous perturbations: oxygen depletion and relief of glucose limitation. Results The shift towards fully fermentative conditions caused a massive transcriptional reprogramming, where one third of all genes within the genome were transcribed differentially. The changes in transcript levels were mostly driven by relief from glucose-limitation. After an initial strong response to the addition of glucose, the expression profile of most transcriptionally regulated genes displayed a clear switch at 30 minutes. In this respect, a striking difference was observed between the transcript profiles of genes encoding ribosomal proteins and those encoding ribosomal biogenesis components. Not all regulated genes responded with this binary profile. A group of 87 genes showed a delayed and steady increase in expression that specifically responded to anaerobiosis. Conclusion Our study demonstrated that, despite the complexity of this multiple-input perturbation, the transcriptional responses could be categorized and biologically interpreted. By comparing this study with public datasets representing dynamic and steady conditions, 14 up-regulated and 11 down-regulated genes were determined to be anaerobic specific. Therefore, these can be seen as true "signature" transcripts for anaerobicity under dynamic as well as under steady state conditions.
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Pham TK, Wright PC. Proteomic Analysis of Calcium Alginate-Immobilized Saccharomyces cerevisiae under High-Gravity Fermentation Conditions. J Proteome Res 2008; 7:515-25. [DOI: 10.1021/pr070391h] [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]
Affiliation(s)
- Trong Khoa Pham
- Biological and Environmental Systems Group, Department of Chemical and Process Engineering, The University of Sheffield, Mappin Street, Sheffield S1 3JD, U.K
| | - Phillip C. Wright
- Biological and Environmental Systems Group, Department of Chemical and Process Engineering, The University of Sheffield, Mappin Street, Sheffield S1 3JD, U.K
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Albers E, Larsson C, Andlid T, Walsh MC, Gustafsson L. Effect of nutrient starvation on the cellular composition and metabolic capacity of Saccharomyces cerevisiae. Appl Environ Microbiol 2007; 73:4839-48. [PMID: 17545328 PMCID: PMC1951042 DOI: 10.1128/aem.00425-07] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2007] [Accepted: 05/24/2007] [Indexed: 11/20/2022] Open
Abstract
This investigation addresses the following question: what are the important factors for maintenance of a high catabolic capacity under various starvation conditions? Saccharomyces cerevisiae was cultured in aerobic batch cultures, and during the diauxic shift cells were transferred and subjected to 24 h of starvation. The following conditions were used: carbon starvation, nitrogen starvation in the presence of glucose or ethanol, and both carbon starvation and nitrogen starvation. During the starvation period changes in biomass composition (including protein, carbohydrate, lipid, and nucleic acid contents), metabolic activity, sugar transport kinetics, and the levels of selected enzymes were recorded. Subsequent to the starvation period the remaining catabolic capacity was measured by addition of 50 mM glucose. The results showed that the glucose transport capacity is a key factor for maintenance of high metabolic capacity in many, but not all, cases. The results for cells starved of carbon, carbon and nitrogen, or nitrogen in the presence of glucose all indicated that the metabolic capacity was indeed controlled by the glucose transport ability, perhaps with some influence of hexokinase, phosphofructokinase, aldolase, and enolase levels. However, it was also demonstrated that there was no such correlation when nitrogen starvation occurred in the presence of ethanol instead of glucose.
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Affiliation(s)
- Eva Albers
- Department of Chemical and Biological Engineering-Molecular Biotechnology, Chalmers University of Technology, Box 462, SE-405 30 Göteborg, Sweden
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Brandberg T, Gustafsson L, Franzén CJ. The impact of severe nitrogen limitation and microaerobic conditions on extended continuous cultivations of Saccharomyces cerevisiae with cell recirculation. Enzyme Microb Technol 2007. [DOI: 10.1016/j.enzmictec.2006.05.032] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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26
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Rossell S, van der Weijden CC, Lindenbergh A, van Tuijl A, Francke C, Bakker BM, Westerhoff HV. Unraveling the complexity of flux regulation: a new method demonstrated for nutrient starvation in Saccharomyces cerevisiae. Proc Natl Acad Sci U S A 2006; 103:2166-71. [PMID: 16467155 PMCID: PMC1413710 DOI: 10.1073/pnas.0509831103] [Citation(s) in RCA: 112] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
An important question is to what extent metabolic fluxes are regulated by gene expression or by metabolic regulation. There are two distinct aspects to this question: (i) the local regulation of the fluxes through the individual steps in the pathway and (ii) the influence of such local regulation on the pathway's flux. We developed regulation analysis so as to address the former aspect for all steps in a pathway. We demonstrate the method for the issue of how Saccharomyces cerevisiae regulates the fluxes through its individual glycolytic and fermentative enzymes when confronted with nutrient starvation. Regulation was dissected quantitatively into (i) changes in maximum enzyme activity (Vmax, called hierarchical regulation) and (ii) changes in the interaction of the enzyme with the rest of metabolism (called metabolic regulation). Within a single pathway, the regulation of the fluxes through individual steps varied from fully hierarchical to exclusively metabolic. Existing paradigms of flux regulation (such as single- and multisite modulation and exclusively metabolic regulation) were tested for a complete pathway and falsified for a major pathway in an important model organism. We propose a subtler mechanism of flux regulation, with different roles for different enzymes, i.e., "leader," "follower," or "conservative," the latter attempting to hold back the change in flux. This study makes this subtlety, so typical for biological systems, tractable experimentally and invites reformulation of the questions concerning the drives and constraints governing metabolic flux regulation.
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Affiliation(s)
- Sergio Rossell
- *Faculty of Earth and Life Sciences, Department of Molecular Cell Physiology, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam, The Netherlands
| | - Coen C. van der Weijden
- *Faculty of Earth and Life Sciences, Department of Molecular Cell Physiology, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam, The Netherlands
| | - Alexander Lindenbergh
- *Faculty of Earth and Life Sciences, Department of Molecular Cell Physiology, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam, The Netherlands
| | - Arjen van Tuijl
- *Faculty of Earth and Life Sciences, Department of Molecular Cell Physiology, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam, The Netherlands
| | - Christof Francke
- *Faculty of Earth and Life Sciences, Department of Molecular Cell Physiology, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam, The Netherlands
- Wageningen Centre for Food Sciences, P.O. Box 557, 6700 AN, Wagenigen, The Netherlands
| | - Barbara M. Bakker
- *Faculty of Earth and Life Sciences, Department of Molecular Cell Physiology, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam, The Netherlands
| | - Hans V. Westerhoff
- *Faculty of Earth and Life Sciences, Department of Molecular Cell Physiology, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam, The Netherlands
- Department of Mathematical Biochemistry, BioCentrum Amsterdam, Swammerdam Institute for Life Sciences, Kruislaan 318, 1098 SM, Amsterdam, The Netherlands
- Manchester Centre for Integrative Systems Biology, University of Manchester, P.O. Box 88, Sackville Street, Manchester M60 1QD, United Kingdom; and
- **To whom correspondence should be addressed. E-mail:
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Thomsson E, Larsson C. The effect of lactic acid on anaerobic carbon or nitrogen limited chemostat cultures of Saccharomyces cerevisiae. Appl Microbiol Biotechnol 2005; 71:533-42. [PMID: 16317544 DOI: 10.1007/s00253-005-0195-3] [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: 07/06/2005] [Revised: 09/13/2005] [Accepted: 09/17/2005] [Indexed: 10/25/2022]
Abstract
Weak organic acids are well-known metabolic effectors in yeast and other micro-organisms. High concentrations of lactic acid due to infection of lactic acid bacteria often occurs in combination with growth under nutrient-limiting conditions in industrial yeast fermentations. The effects of lactic acid on growth and product formation of Saccharomyces cerevisiae were studied, with cells growing under carbon- or nitrogen-limiting conditions in anaerobic chemostat cultures (D=0.1 h(-1)) at pH values 3.25 and 5. It was shown that lactic acid in industrially relevant concentrations had a rather limited effect on the metabolism of S. cerevisiae. However, there was an effect on the energetic status of the cells, i.e. lactic acid addition provoked a reduction in the adenosine triphosphate (ATP) content of the cells. The decrease in ATP was not accompanied by a significant increase in the adenosine monophosphate levels.
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Affiliation(s)
- Elisabeth Thomsson
- Department of Chemistry and Bioscience, Molecular Biotechnology, Lundberg Laboratory, Chalmers University of Technology, Box 462, 405 30, Gothenburg, Sweden.
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Thomsson E, Svensson M, Larsson C. Rapamycin pre-treatment preserves viability, ATP level and catabolic capacity during carbon starvation of Saccharomyces cerevisiae. Yeast 2005; 22:615-23. [PMID: 16034823 DOI: 10.1002/yea.1219] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Saccharomyces cerevisiae growing exponentially in anaerobic batch cultures that are suddenly exposed to carbon starvation will rapidly lose almost all ATP. This will cause an energy deficiency and adaptation to starvation conditions is prohibited. As a result, viability and fermentative capacity will be drastically reduced during prolonged starvation. However, if the cells are incubated in the presence of rapamycin (which will inactivate the TOR pathway) before carbon starvation ATP levels, viability and fermentative capacity will be preserved to a much larger extent compared to untreated cells. The beneficial effect of rapamycin cannot be explained by induction of a stationary phase phenotype. In fact, under these anaerobic well-controlled growth conditions, rapamycin-treated cells were still metabolically active and continued to grow, albeit not exponentially and with a reduced protein content. It is hypothesized that the loss of ATP during carbon starvation occurs because protein synthesis does not make an immediate arrest at the onset of starvation. Since there are no external or internal energy sources, this will rapidly deplete the cells of ATP. Rapamycin-treated cells, on the other hand, have already downregulated the protein-synthesizing machinery and are thus better suited to cope with a sudden carbon starvation condition. This hypothesis is strengthened by the fact that treating the cells with the protein synthesis inhibitor cycloheximide also improves the carbon starvation tolerance, although not to the same extent as rapamycin. The even better effect of rapamycin is explained by accumulation of storage carbohydrates, which is not observed for cycloheximide-treated cells.
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Affiliation(s)
- Elisabeth Thomsson
- Department of Chemistry and Bioscience, Lundberg Laboratory, Chalmers University of Technology, Box 462, SE-405 30 Gothenburg, Sweden
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Rossell S, van der Weijden CC, Kruckeberg AL, Bakker BM, Westerhoff HV. Hierarchical and metabolic regulation of glucose influx in starved Saccharomyces cerevisiae. FEMS Yeast Res 2005; 5:611-9. [PMID: 15780660 DOI: 10.1016/j.femsyr.2004.11.003] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2004] [Revised: 11/01/2004] [Accepted: 11/05/2004] [Indexed: 11/20/2022] Open
Abstract
A novel method dissecting the regulation of a cellular function into direct metabolic regulation and hierarchical (e.g., gene-expression) regulation is applied to yeast starved for nitrogen or carbon. Upon nitrogen starvation glucose influx is down-regulated hierarchically. Upon carbon starvation it is down-regulated both metabolically and hierarchically. The method is expounded in terms of its implications for diverse types of regulation. It is also fine-tuned for cases where isoenzymes catalyze the flux through a single metabolic step.
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Affiliation(s)
- Sergio Rossell
- Department of Molecular Cell Physiology, Faculty of Earth and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, NL-1081 HV Amsterdam, The Netherlands
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30
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Thomsson E, Gustafsson L, Larsson C. Starvation response of Saccharomyces cerevisiae grown in anaerobic nitrogen- or carbon-limited chemostat cultures. Appl Environ Microbiol 2005; 71:3007-13. [PMID: 15932996 PMCID: PMC1151810 DOI: 10.1128/aem.71.6.3007-3013.2005] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2004] [Accepted: 12/21/2004] [Indexed: 11/20/2022] Open
Abstract
Anaerobic starvation conditions are frequent in industrial fermentation and can affect the performance of the cells. In this study, the anaerobic carbon or nitrogen starvation response of Saccharomyces cerevisiae was investigated for cells grown in anaerobic carbon or nitrogen-limited chemostat cultures at a dilution rate of 0.1 h(-1) at pH 3.25 or 5. Lactic or benzoic acid was present in the growth medium at different concentrations, resulting in 16 different growth conditions. At steady state, cells were harvested and then starved for either carbon or nitrogen for 24 h under anaerobic conditions. We measured fermentative capacity, glucose uptake capacity, intracellular ATP content, and reserve carbohydrates and found that the carbon, but not the nitrogen, starvation response was dependent upon the previous growth conditions. All cells subjected to nitrogen starvation retained a large portion of their initial fermentative capacity, independently of previous growth conditions. However, nitrogen-limited cells that were starved for carbon lost almost all their fermentative capacity, while carbon-limited cells managed to preserve a larger portion of their fermentative capacity during carbon starvation. There was a positive correlation between the amount of glycogen before carbon starvation and the fermentative capacity and ATP content of the cells after carbon starvation. Fermentative capacity and glucose uptake capacity were not correlated under any of the conditions tested. Thus, the successful adaptation to sudden carbon starvation requires energy and, under anaerobic conditions, fermentable endogenous resources. In an industrial setting, carbon starvation in anaerobic fermentations should be avoided to maintain a productive yeast population.
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Affiliation(s)
- Elisabeth Thomsson
- Department of Chemistry and Bioscience, Molecular Biotechnology, Lundberg Laboratory, Chalmers University of Technology, Box 462, SE-405 30 Gothenburg, Sweden.
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