1
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Wang S, Meng D, Feng M, Li C, Wang Y. Efficient Plant Triterpenoids Synthesis in Saccharomyces cerevisiae: from Mechanisms to Engineering Strategies. ACS Synth Biol 2024; 13:1059-1076. [PMID: 38546129 DOI: 10.1021/acssynbio.4c00061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/20/2024]
Abstract
Triterpenoids possess a range of biological activities and are extensively utilized in the pharmaceutical, food, cosmetic, and chemical industries. Traditionally, they are acquired through chemical synthesis and plant extraction. However, these methods have drawbacks, including high energy consumption, environmental pollution, and being time-consuming. Recently, the de novo synthesis of triterpenoids in microbial cell factories has been achieved. This represents a promising and environmentally friendly alternative to traditional supply methods. Saccharomyces cerevisiae, known for its robustness, safety, and ample precursor supply, stands out as an ideal candidate for triterpenoid biosynthesis. However, challenges persist in industrial production and economic feasibility of triterpenoid biosynthesis. Consequently, metabolic engineering approaches have been applied to improve the triterpenoid yield, leading to substantial progress. This review explores triterpenoids biosynthesis mechanisms in S. cerevisiae and strategies for efficient production. Finally, the review also discusses current challenges and proposes potential solutions, offering insights for future engineering.
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Affiliation(s)
- Shuai Wang
- Key Laboratory of Medical Molecule Science and Pharmaceutical Engineering, Ministry of Industry and Information Technology, Institute of Biochemical Engineering, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Dong Meng
- Key Laboratory of Medical Molecule Science and Pharmaceutical Engineering, Ministry of Industry and Information Technology, Institute of Biochemical Engineering, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Meilin Feng
- Key Laboratory of Medical Molecule Science and Pharmaceutical Engineering, Ministry of Industry and Information Technology, Institute of Biochemical Engineering, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Chun Li
- Key Laboratory for Industrial Biocatalysis, Ministry of Education, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China
| | - Ying Wang
- Key Laboratory of Medical Molecule Science and Pharmaceutical Engineering, Ministry of Industry and Information Technology, Institute of Biochemical Engineering, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China
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2
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Wang H, Tang J, Lv J, Wang X, Sun H. Physiological and transcriptomic insights into sugar stress resistance in osmophilic yeast Zygosaccharomyces rouxii. Food Microbiol 2024; 117:104395. [PMID: 37919004 DOI: 10.1016/j.fm.2023.104395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 09/10/2023] [Accepted: 10/02/2023] [Indexed: 11/04/2023]
Abstract
The osmophilic yeast Zygosaccharomyces rouxii has attracted increasing attention for its ability to survive and grow in extremely high sugar environments. This trait determines its role in fermentation process and results in contamination in the food industry. However, the behavior of Z. rouxii in regulating cell metabolism to combat high sugar stress and the corresponding mechanism have not been completely elucidated. Here, the resistance strategies of Z. rouxii against high glucose stress were explored by physiological analysis at cell membrane level and transcriptomic analysis. Physiological analysis showed that under high glucose stress, colony transparency increased, cell volume decreased, which was accompanied by reduction in permeability and integrity of cell membrane and subsequent gradual recovering. Additionally, the proportion of ergosterol and unsaturated fatty acids in cell membrane significantly increased under high glucose stress. A comparison of transcriptome data showed that most of the obtained differentially expressed genes (DEGs) involved in ergosterol and linoleic acid synthesis pathways as well as cell wall integrity (CWI) and high osmolarity glycerol mitogen-activated protein kinase (HOG-MAPK) pathways, which was in line with the results of physiological data. Our results provided a theoretic basis to develop the process control for the production of high sugar foods.
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Affiliation(s)
- Huxuan Wang
- School of Food Science and Engineering, Shaanxi University of Science and Technology, Xi'an, Shaanxi, 710021, China.
| | - Jingqi Tang
- School of Food Science and Engineering, Shaanxi University of Science and Technology, Xi'an, Shaanxi, 710021, China
| | - Jiayao Lv
- School of Food Science and Engineering, Shaanxi University of Science and Technology, Xi'an, Shaanxi, 710021, China
| | - Xuanzhi Wang
- School of Food Science and Engineering, Shaanxi University of Science and Technology, Xi'an, Shaanxi, 710021, China
| | - Hongmin Sun
- School of Food Science and Engineering, Shaanxi University of Science and Technology, Xi'an, Shaanxi, 710021, China
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3
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Jordá T, Barba-Aliaga M, Rozès N, Alepuz P, Martínez-Pastor MT, Puig S. Transcriptional regulation of ergosterol biosynthesis genes in response to iron deficiency. Environ Microbiol 2022; 24:5248-5260. [PMID: 36382795 DOI: 10.1111/1462-2920.16157] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 08/01/2022] [Indexed: 01/07/2023]
Abstract
Iron participates as an essential cofactor in the biosynthesis of critical cellular components, including DNA, proteins and lipids. The ergosterol biosynthetic pathway, which is an important target of antifungal treatments, depends on iron in four enzymatic steps. Our results in the model yeast Saccharomyces cerevisiae show that the expression of ergosterol biosynthesis (ERG) genes is tightly modulated by iron availability probably through the iron-dependent variation of sterol and heme levels. Whereas the transcription factors Upc2 and Ecm22 are responsible for the activation of ERG genes upon iron deficiency, the heme-dependent factor Hap1 triggers their Tup1-mediated transcriptional repression. The combined regulation by both activating and repressing regulatory factors allows for the fine-tuning of ERG transcript levels along the progress of iron deficiency, avoiding the accumulation of toxic sterol intermediates and enabling efficient adaptation to rapidly changing conditions. The lack of these regulatory factors leads to changes in the yeast sterol profile upon iron-deficient conditions. Both environmental iron availability and specific regulatory factors should be considered in ergosterol antifungal treatments.
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Affiliation(s)
- Tania Jordá
- Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de Alimentos (IATA), Consejo Superior de Investigaciones Científicas (CSIC), Paterna, Valencia, Spain
| | - Marina Barba-Aliaga
- Instituto de Biotecnología y Biomedicina (Biotecmed), Universitat de València, Burjassot, Valencia, Spain.,Departamento de Bioquímica y Biología Molecular, Universitat de València, Burjassot, Valencia, Spain
| | - Nicolas Rozès
- Departament de Bioquímica i Biotecnologia, Facultat d'Enologia, Universitat Rovira i Virgili, Tarragona, Spain
| | - Paula Alepuz
- Instituto de Biotecnología y Biomedicina (Biotecmed), Universitat de València, Burjassot, Valencia, Spain.,Departamento de Bioquímica y Biología Molecular, Universitat de València, Burjassot, Valencia, Spain
| | | | - Sergi Puig
- Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de Alimentos (IATA), Consejo Superior de Investigaciones Científicas (CSIC), Paterna, Valencia, Spain
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4
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Pereira de Sa N, Del Poeta M. Sterylglucosides in Fungi. J Fungi (Basel) 2022; 8:1130. [PMID: 36354897 PMCID: PMC9698648 DOI: 10.3390/jof8111130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 10/24/2022] [Accepted: 10/24/2022] [Indexed: 11/16/2022] Open
Abstract
Sterylglucosides (SGs) are sterol conjugates widely distributed in nature. Although their universal presence in all living organisms suggests the importance of this kind of glycolipids, they are yet poorly understood. The glycosylation of sterols confers a more hydrophilic character, modifying biophysical properties of cell membranes and altering immunogenicity of the cells. In fungi, SGs regulate different cell pathways to help overcome oxygen and pH challenges, as well as help to accomplish cell recycling and other membrane functions. At the same time, the level of these lipids is highly controlled, especially in wild-type fungi. In addition, modulating SGs metabolism is becoming a novel tool for vaccine and antifungal development. In the present review, we bring together multiple observations to emphasize the underestimated importance of SGs for fungal cell functions.
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Affiliation(s)
- Nivea Pereira de Sa
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, NY 11794, USA
| | - Maurizio Del Poeta
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, NY 11794, USA
- Institute of Chemical Biology and Drug Discovery (ICB&DD), Stony Brook, NY 11794, USA
- Division of Infectious Diseases, School of Medicine, Stony Brook University, Stony Brook, NY 11794, USA
- Veterans Administration Medical Center, Northport, NY 11768, USA
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5
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Betinova V, Toth Hervay N, Elias D, Horvathova A, Gbelska Y. The UPC2 gene in Kluyveromyces lactis stress adaptation. Folia Microbiol (Praha) 2022; 67:641-647. [PMID: 35352326 DOI: 10.1007/s12223-022-00968-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 03/10/2022] [Indexed: 11/25/2022]
Abstract
KlUpc2p, a transcription factor belonging to the fungal binuclear cluster family, is an important regulator of ergosterol biosynthesis and azole drug resistance in Kluyveromyces lactis. In this work, we show that the absence of KlUpc2p generates Rag- phenotype and modulates the K. lactis susceptibility to oxidants and calcofuor white. The KlUPC2 deletion leads to increased expression of KlMGA2 gene, encoding an important regulator of hypoxic and lipid biosynthetic genes in K. lactis and also KlHOG1 gene. The absence of KlUpc2p does not lead to statistically significant changes in glycerol, corroborating the expression of KlGPD1 gene, encoding NAD+-dependent glycerol-3-phosphate dehydrogenase, that is similar in both the deletion mutant and the parental wild-type strain. Increased sensitivity of Klupc2 mutant cells to brefeldin A accompanied with significant increase in KlARF2 gene expression point to the involvement of KlUpc2p in intracellular signaling. Our observations highlight the connections between ergosterol and fatty acid metabolism to modulate membrane properties and point to the possible involvement of KlUpc2p in K. lactis oxidative stress response.
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Affiliation(s)
- Veronika Betinova
- Faculty of Natural Sciences, Department of Microbiology and Virology, Comenius University in Bratislava, Ilkovicova 6, 842 15, Bratislava, Slovak Republic
| | - Nora Toth Hervay
- Faculty of Natural Sciences, Department of Microbiology and Virology, Comenius University in Bratislava, Ilkovicova 6, 842 15, Bratislava, Slovak Republic
| | - Daniel Elias
- Faculty of Natural Sciences, Department of Microbiology and Virology, Comenius University in Bratislava, Ilkovicova 6, 842 15, Bratislava, Slovak Republic
| | - Agnes Horvathova
- Centre for Glycomics, Institute of Chemistry, Slovak Academy of Sciences, Dúbravská cesta 9, 845 38, Bratislava, Slovak Republic
| | - Yvetta Gbelska
- Faculty of Natural Sciences, Department of Microbiology and Virology, Comenius University in Bratislava, Ilkovicova 6, 842 15, Bratislava, Slovak Republic.
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6
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Characterization and Role of Sterols in Saccharomyces cerevisiae during White Wine Alcoholic Fermentation. FERMENTATION 2022. [DOI: 10.3390/fermentation8020090] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Responsible for plasma membrane structure maintenance in eukaryotic organisms, sterols are essential for yeast development. The role of two sterol sources in Saccharomyces cerevisiae during wine fermentation is highlighted in this review: ergosterol (yeast sterol produced by yeast cells under aerobic conditions) and phytosterols (plant sterols imported by yeast cells from grape musts in the absence of oxygen). These compounds are responsible for the maintenance of yeast cell viability during white wine fermentation under stress conditions, such as ethanol stress and sterol starvation, to avoid sluggish and stuck fermentations.
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7
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Gu Y, Jiao X, Ye L, Yu H. Metabolic engineering strategies for de novo biosynthesis of sterols and steroids in yeast. BIORESOUR BIOPROCESS 2021; 8:110. [PMID: 38650187 PMCID: PMC10992410 DOI: 10.1186/s40643-021-00460-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 10/16/2021] [Indexed: 12/17/2022] Open
Abstract
Steroidal compounds are of great interest in the pharmaceutical field, with steroidal drugs as the second largest category of medicine in the world. Advances in synthetic biology and metabolic engineering have enabled de novo biosynthesis of sterols and steroids in yeast, which is a green and safe production route for these valuable steroidal compounds. In this review, we summarize the metabolic engineering strategies developed and employed for improving the de novo biosynthesis of sterols and steroids in yeast based on the regulation mechanisms, and introduce the recent progresses in de novo synthesis of some typical sterols and steroids in yeast. The remaining challenges and future perspectives are also discussed.
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Affiliation(s)
- Yuehao Gu
- Key Laboratory of Biomass Chemical Engineering (Education Ministry), College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China
- Institute of Bioengineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Xue Jiao
- Institute of Bioengineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Lidan Ye
- Key Laboratory of Biomass Chemical Engineering (Education Ministry), College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China.
- Institute of Bioengineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China.
| | - Hongwei Yu
- Key Laboratory of Biomass Chemical Engineering (Education Ministry), College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China.
- Institute of Bioengineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China.
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8
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Kern AF, Yang GX, Khosla NM, Ang RML, Snyder MP, Fraser HB. Divergent patterns of selection on metabolite levels and gene expression. BMC Ecol Evol 2021; 21:185. [PMID: 34587900 PMCID: PMC8482673 DOI: 10.1186/s12862-021-01915-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 09/06/2021] [Indexed: 11/19/2022] Open
Abstract
Background Natural selection can act on multiple genes in the same pathway, leading to polygenic adaptation. For example, adaptive changes were found to down-regulate six genes involved in ergosterol biosynthesis—an essential pathway targeted by many antifungal drugs—in some strains of the yeast Saccharomyces cerevisiae. However, the impact of this polygenic adaptation on metabolite levels was unknown. Here, we performed targeted mass spectrometry to measure the levels of eight metabolites in this pathway in 74 yeast strains from a genetic cross. Results Through quantitative trait locus (QTL) mapping we identified 19 loci affecting ergosterol pathway metabolite levels, many of which overlap loci that also impact gene expression within the pathway. We then used the recently developed v-test, which identified selection acting upon three metabolite levels within the pathway, none of which were predictable from the gene expression adaptation. Conclusions These data showed that effects of selection on metabolite levels were complex and not predictable from gene expression data. This suggests that a deeper understanding of metabolism is necessary before we can understand the impacts of even relatively straightforward gene expression adaptations on metabolic pathways. Supplementary Information The online version contains supplementary material available at 10.1186/s12862-021-01915-5.
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Affiliation(s)
| | | | - Neil M Khosla
- Department of Biology, Stanford University, Stanford, CA, USA
| | - Roy Moh Lik Ang
- Department of Genetics, Stanford University, Stanford, CA, USA
| | | | - Hunter B Fraser
- Department of Biology, Stanford University, Stanford, CA, USA.
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9
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Regulation of Ergosterol Biosynthesis in Saccharomyces cerevisiae. Genes (Basel) 2020; 11:genes11070795. [PMID: 32679672 PMCID: PMC7397035 DOI: 10.3390/genes11070795] [Citation(s) in RCA: 169] [Impact Index Per Article: 42.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 07/06/2020] [Accepted: 07/13/2020] [Indexed: 12/14/2022] Open
Abstract
Ergosterol is an essential component of fungal cell membranes that determines the fluidity, permeability and activity of membrane-associated proteins. Ergosterol biosynthesis is a complex and highly energy-consuming pathway that involves the participation of many enzymes. Deficiencies in sterol biosynthesis cause pleiotropic defects that limit cellular proliferation and adaptation to stress. Thereby, fungal ergosterol levels are tightly controlled by the bioavailability of particular metabolites (e.g., sterols, oxygen and iron) and environmental conditions. The regulation of ergosterol synthesis is achieved by overlapping mechanisms that include transcriptional expression, feedback inhibition of enzymes and changes in their subcellular localization. In the budding yeast Saccharomyces cerevisiae, the sterol regulatory element (SRE)-binding proteins Upc2 and Ecm22, the heme-binding protein Hap1 and the repressor factors Rox1 and Mot3 coordinate ergosterol biosynthesis (ERG) gene expression. Here, we summarize the sterol biosynthesis, transport and detoxification systems of S. cerevisiae, as well as its adaptive response to sterol depletion, low oxygen, hyperosmotic stress and iron deficiency. Because of the large number of ERG genes and the crosstalk between different environmental signals and pathways, many aspects of ergosterol regulation are still unknown. The study of sterol metabolism and its regulation is highly relevant due to its wide applications in antifungal treatments, as well as in food and pharmaceutical industries.
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10
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Sinha A, Israeli R, Cirigliano A, Gihaz S, Trabelcy B, Braus GH, Gerchman Y, Fishman A, Negri R, Rinaldi T, Pick E. The COP9 signalosome mediates the Spt23 regulated fatty acid desaturation and ergosterol biosynthesis. FASEB J 2020; 34:4870-4889. [PMID: 32077151 DOI: 10.1096/fj.201902487r] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 01/02/2020] [Accepted: 01/14/2020] [Indexed: 02/06/2023]
Abstract
The COP9 signalosome (CSN) is a conserved eukaryotic complex, essential for vitality in all multicellular organisms and critical for the turnover of key cellular proteins through catalytic and non-catalytic activities. Saccharomyces cerevisiae is a powerful model organism for studying fundamental aspects of the CSN complex, since it includes a conserved enzymatic core but lacks non-catalytic activities, probably explaining its non-essentiality for life. A previous transcriptomic analysis of an S. cerevisiae strain deleted in the CSN5/RRI1 gene, encoding to the CSN catalytic subunit, revealed a downregulation of genes involved in lipid metabolism. We now show that the S. cerevisiae CSN holocomplex is essential for cellular lipid homeostasis. Defects in CSN assembly or activity lead to decreased quantities of ergosterol and unsaturated fatty acids (UFA); vacuole defects; diminished lipid droplets (LDs) size; and to accumulation of endoplasmic reticulum (ER) stress. The molecular mechanism behind these findings depends on CSN involvement in upregulating mRNA expression of SPT23. Spt23 is a novel activator of lipid desaturation and ergosterol biosynthesis. Our data reveal for the first time a functional link between the CSN holocomplex and Spt23. Moreover, CSN-dependent upregulation of SPT23 transcription is necessary for the fine-tuning of lipid homeostasis and for cellular health.
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Affiliation(s)
- Abhishek Sinha
- Department of Biology and Environment, Faculty of Natural Sciences, University of Haifa, Oranim, Israel
| | - Ran Israeli
- Department of Biology and Environment, Faculty of Natural Sciences, University of Haifa, Oranim, Israel
| | - Angela Cirigliano
- Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, Rome, Italy
| | - Shalev Gihaz
- Department of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Haifa, Israel
| | - Beny Trabelcy
- Department of Biology and Environment, Faculty of Natural Sciences, University of Haifa, Oranim, Israel
| | - Gerhard H Braus
- Department of Molecular Microbiology and Genetics, Institute of Microbiology and Genetics, Goettingen Center for Molecular Biosciences (GZMB), University of Goettingen, Goettingen, Germany
| | - Yoram Gerchman
- Department of Biology and Environment, Faculty of Natural Sciences, University of Haifa, Oranim, Israel
| | - Ayelet Fishman
- Department of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Haifa, Israel
| | - Rodolfo Negri
- Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, Rome, Italy
| | - Teresa Rinaldi
- Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, Rome, Italy
| | - Elah Pick
- Department of Biology and Environment, Faculty of Natural Sciences, University of Haifa, Oranim, Israel
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11
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He Z, Zhao X, Gao Y, Keyhani NO, Wang H, Deng J, Lu Z, Kan Y, Luo Z, Zhang Y. The fungal mitochondrial membrane protein, BbOhmm, antagonistically controls hypoxia tolerance. Environ Microbiol 2020; 22:2514-2535. [DOI: 10.1111/1462-2920.14910] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 12/23/2019] [Accepted: 12/29/2019] [Indexed: 01/15/2023]
Affiliation(s)
- Zhangjiang He
- Biotechnology Research Center, State Cultivation Base of Crop Stress Biology for Southern Mountainous Land of Southwest University, Academy of Agricultural SciencesSouthwest University Chongqing 400715 China
- Biochemical Engineering Center of Guizhou ProvinceGuizhou University Guiyang 50025 China
| | - Xin Zhao
- Biotechnology Research Center, State Cultivation Base of Crop Stress Biology for Southern Mountainous Land of Southwest University, Academy of Agricultural SciencesSouthwest University Chongqing 400715 China
| | - Yifei Gao
- Biotechnology Research Center, State Cultivation Base of Crop Stress Biology for Southern Mountainous Land of Southwest University, Academy of Agricultural SciencesSouthwest University Chongqing 400715 China
| | - Nemat O. Keyhani
- Department of Microbiology and Cell ScienceUniversity of Florida Gainesville FL 32611 USA
| | - Huifang Wang
- Biotechnology Research Center, State Cultivation Base of Crop Stress Biology for Southern Mountainous Land of Southwest University, Academy of Agricultural SciencesSouthwest University Chongqing 400715 China
| | - Juan Deng
- Biotechnology Research Center, State Cultivation Base of Crop Stress Biology for Southern Mountainous Land of Southwest University, Academy of Agricultural SciencesSouthwest University Chongqing 400715 China
| | - Zhuoyue Lu
- Biotechnology Research Center, State Cultivation Base of Crop Stress Biology for Southern Mountainous Land of Southwest University, Academy of Agricultural SciencesSouthwest University Chongqing 400715 China
| | - Yanze Kan
- Biotechnology Research Center, State Cultivation Base of Crop Stress Biology for Southern Mountainous Land of Southwest University, Academy of Agricultural SciencesSouthwest University Chongqing 400715 China
| | - Zhibing Luo
- Biotechnology Research Center, State Cultivation Base of Crop Stress Biology for Southern Mountainous Land of Southwest University, Academy of Agricultural SciencesSouthwest University Chongqing 400715 China
| | - Yongjun Zhang
- Biotechnology Research Center, State Cultivation Base of Crop Stress Biology for Southern Mountainous Land of Southwest University, Academy of Agricultural SciencesSouthwest University Chongqing 400715 China
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12
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Cirigliano A, Amelina A, Biferali B, Macone A, Mozzetta C, Bianchi MM, Mori M, Botta B, Pick E, Negri R, Rinaldi T. Statins interfere with the attachment of S. cerevisiae mtDNA to the inner mitochondrial membrane. J Enzyme Inhib Med Chem 2019; 35:129-137. [PMID: 31694426 PMCID: PMC6844431 DOI: 10.1080/14756366.2019.1687461] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The 3-hydroxy-3-methylglutaryl-CoA reductase, a key enzyme of the mevalonate pathway for the synthesis of cholesterol in mammals (ergosterol in fungi), is inhibited by statins, a class of cholesterol lowering drugs. Indeed, statins are in a wide medical use, yet statins treatment could induce side effects as hepatotoxicity and myopathy in patients. We used Saccharomyces cerevisiae as a model to investigate the effects of statins on mitochondria. We demonstrate that statins are active in S.cerevisiae by lowering the ergosterol content in cells and interfering with the attachment of mitochondrial DNA to the inner mitochondrial membrane. Experiments on murine myoblasts confirmed these results in mammals. We propose that the instability of mitochondrial DNA is an early indirect target of statins.
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Affiliation(s)
- Angela Cirigliano
- Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, Rome, Italy
| | - Antonia Amelina
- Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, Rome, Italy
| | - Beatrice Biferali
- Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, Rome, Italy.,Institute of Molecular Biology and Pathology, CNR, Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, Rome, Italy
| | - Alberto Macone
- Pasteur Institute-Cenci Bolognetti Foundation, Rome, Italy.,Institute of Molecular Biology and Pathology, CNR, Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Sapienza University of Rome, Rome, Italy
| | - Chiara Mozzetta
- Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, Rome, Italy.,Institute of Molecular Biology and Pathology, CNR, Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, Rome, Italy
| | - Michele Maria Bianchi
- Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, Rome, Italy
| | - Mattia Mori
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Siena, Italy
| | - Bruno Botta
- Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza University of Rome, Rome, Italy
| | - Elah Pick
- Department of Biology and Environment, Faculty of Natural Sciences, University of Haifa at Oranim, Tivon, Israel
| | - Rodolfo Negri
- Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, Rome, Italy.,Institute of Molecular Biology and Pathology, CNR, Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, Rome, Italy
| | - Teresa Rinaldi
- Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, Rome, Italy.,Pasteur Institute-Cenci Bolognetti Foundation, Rome, Italy
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13
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Transcriptomic Response of Saccharomyces cerevisiae during Fermentation under Oleic Acid and Ergosterol Depletion. FERMENTATION-BASEL 2019. [DOI: 10.3390/fermentation5030057] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Under anaerobic/hypoxic conditions, Saccharomyces cerevisiae relies on external lipid supplements to modulate membrane lipid fraction in response to different stresses. Here, transcriptomic responses of two S. cerevisiae wine strains were evaluated during hypoxic fermentation of a synthetic must with/without ergosterol and oleic acid supplementation. In the absence of lipids, the two strains, namely EC1118 and M25, showed different behaviour, with M25 significantly decreasing its fermentation rate from the 72 h after inoculum. At this time point, the whole genome transcriptomic analysis revealed common and strain-specific responses to the lack of lipid supplementation. Common responses included the upregulation of the genes involved in ergosterol biosynthesis, as well as the seripauperin and the heat shock protein multigene families. In addition, the upregulation of the aerobic isoforms of genes involved in mitochondrial electron transport is compatible with the previously observed accumulation of reactive oxygen species in the two strains during growth in absence of lipids. Considering the strain-specific responses, M25 downregulated the transcription of genes involved in glucose transport, methionine biosynthesis and of those encoding mannoproteins required for adaptation to low temperatures and hypoxia. The identification of these pathways, which are presumably involved in yeast resistance to stresses, will assist industrial strain selection.
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14
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Degreif D, Cucu B, Budin I, Thiel G, Bertl A. Lipid determinants of endocytosis and exocytosis in budding yeast. Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1864:1005-1016. [DOI: 10.1016/j.bbalip.2019.03.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 02/23/2019] [Accepted: 03/18/2019] [Indexed: 01/10/2023]
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15
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Cirigliano A, Macone A, Bianchi MM, Oliaro-Bosso S, Balliano G, Negri R, Rinaldi T. Ergosterol reduction impairs mitochondrial DNA maintenance in S. cerevisiae. Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1864:290-303. [DOI: 10.1016/j.bbalip.2018.12.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 11/27/2018] [Accepted: 12/10/2018] [Indexed: 12/20/2022]
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16
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Vizoso-Vázquez Á, Lamas-Maceiras M, González-Siso MI, Cerdán ME. Ixr1 Regulates Ribosomal Gene Transcription and Yeast Response to Cisplatin. Sci Rep 2018; 8:3090. [PMID: 29449612 PMCID: PMC5814428 DOI: 10.1038/s41598-018-21439-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 01/30/2018] [Indexed: 11/22/2022] Open
Abstract
Ixr1 is a Saccharomyces cerevisiae HMGB protein that regulates the hypoxic regulon and also controls the expression of other genes involved in the oxidative stress response or re-adaptation of catabolic and anabolic fluxes when oxygen is limiting. Ixr1 also binds with high affinity to cisplatin-DNA adducts and modulates DNA repair. The influence of Ixr1 on transcription in the absence or presence of cisplatin has been analyzed in this work. Ixr1 regulates other transcriptional factors that respond to nutrient availability or extracellular and intracellular stress stimuli, some controlled by the TOR pathway and PKA signaling. Ixr1 controls transcription of ribosomal RNAs and genes encoding ribosomal proteins or involved in ribosome assembly. qPCR, ChIP, and 18S and 25S rRNAs measurement have confirmed this function. Ixr1 binds directly to several promoters of genes related to rRNA transcription and ribosome biogenesis. Cisplatin treatment mimics the effect of IXR1 deletion on rRNA and ribosomal gene transcription, and prevents Ixr1 binding to specific promoters related to these processes.
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Affiliation(s)
- Ángel Vizoso-Vázquez
- Universidade da Coruña, Grupo EXPRELA, Centro de Investigacións Científicas Avanzadas (CICA), Facultade de Ciencias, 15071 A, Coruña, Spain
| | - Mónica Lamas-Maceiras
- Universidade da Coruña, Grupo EXPRELA, Centro de Investigacións Científicas Avanzadas (CICA), Facultade de Ciencias, 15071 A, Coruña, Spain
| | - M Isabel González-Siso
- Universidade da Coruña, Grupo EXPRELA, Centro de Investigacións Científicas Avanzadas (CICA), Facultade de Ciencias, 15071 A, Coruña, Spain
| | - M Esperanza Cerdán
- Universidade da Coruña, Grupo EXPRELA, Centro de Investigacións Científicas Avanzadas (CICA), Facultade de Ciencias, 15071 A, Coruña, Spain.
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A Novel Sterol-Signaling Pathway Governs Azole Antifungal Drug Resistance and Hypoxic Gene Repression in Saccharomyces cerevisiae. Genetics 2017; 208:1037-1055. [PMID: 29263028 DOI: 10.1534/genetics.117.300554] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 12/19/2017] [Indexed: 12/26/2022] Open
Abstract
During antifungal drug treatment and hypoxia, genetic and epigenetic changes occur to maintain sterol homeostasis and cellular function. In this study, we show that SET domain-containing epigenetic factors govern drug efficacy to the medically relevant azole class of antifungal drugs. Upon this discovery, we determined that Set4 is induced when Saccharomyces cerevisiae are treated with azole drugs or grown under hypoxic conditions; two conditions that deplete cellular ergosterol and increase sterol precursors. Interestingly, Set4 induction is controlled by the sterol-sensing transcription factors, Upc2 and Ecm22 To determine the role of Set4 on gene expression under hypoxic conditions, we performed RNA-sequencing analysis and showed that Set4 is required for global changes in gene expression. Specifically, loss of Set4 led to an upregulation of nearly all ergosterol genes, including ERG11 and ERG3, suggesting that Set4 functions in gene repression. Furthermore, mass spectrometry analysis revealed that Set4 interacts with the hypoxic-specific transcriptional repressor, Hap1, where this interaction is necessary for Set4 recruitment to ergosterol gene promoters under hypoxia. Finally, an erg3Δ strain, which produces precursor sterols but lacks ergosterol, expresses Set4 under untreated aerobic conditions. Together, our data suggest that sterol precursors are needed for Set4 induction through an Upc2-mediated mechanism. Overall, this new sterol-signaling pathway governs azole antifungal drug resistance and mediates repression of sterol genes under hypoxic conditions.
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Höfken T. Ecm22 and Upc2 regulate yeast mating through control of expression of the mating genes PRM1 and PRM4. Biochem Biophys Res Commun 2017; 493:1485-1490. [DOI: 10.1016/j.bbrc.2017.10.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 10/01/2017] [Indexed: 10/18/2022]
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Willis SD, Hossian AKMN, Evans N, Hickman MJ. Measuring mRNA Levels Over Time During the Yeast S. cerevisiae Hypoxic Response. J Vis Exp 2017:56226. [PMID: 28829420 PMCID: PMC5614221 DOI: 10.3791/56226] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Complex changes in gene expression typically mediate a large portion of a cellular response. Each gene may change expression with unique kinetics as the gene is regulated by the particular timing of one of many stimuli, signaling pathways or secondary effects. In order to capture the entire gene expression response to hypoxia in the yeast S. cerevisiae, RNA-seq analysis was used to monitor the mRNA levels of all genes at specific times after exposure to hypoxia. Hypoxia was established by growing cells in ~100% N2 gas. Importantly, unlike other hypoxic studies, ergosterol and unsaturated fatty acids were not added to the media because these metabolites affect gene expression. Time points were chosen in the range of 0 - 4 h after hypoxia because that period captures the major changes in gene expression. At each time point, mid-log hypoxic cells were quickly filtered and frozen, limiting exposure to O2 and concomitant changes in gene expression. Total RNA was extracted from cells and used to enrich for mRNA, which was then converted to cDNA. From this cDNA, multiplex libraries were created and eight or more samples were sequenced in one lane of a next-generation sequencer. A post-sequencing pipeline is described, which includes quality base trimming, read mapping and determining the number of reads per gene. DESeq2 within the R statistical environment was used to identify genes that change significantly at any one of the hypoxic time points. Analysis of three biological replicates revealed high reproducibility, genes of differing kinetics and a large number of expected O2-regulated genes. These methods can be used to study how the cells of various organisms respond to hypoxia over time and adapted to study gene expression during other cellular responses.
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Affiliation(s)
- Stephen D Willis
- Department of Molecular Biology, Rowan School of Osteopathic Medicine
| | | | - Nathan Evans
- Department of Biological Sciences, Rowan University
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20
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Recent Advances in Ergosterol Biosynthesis and Regulation Mechanisms in Saccharomyces cerevisiae. Indian J Microbiol 2017; 57:270-277. [PMID: 28904410 DOI: 10.1007/s12088-017-0657-1] [Citation(s) in RCA: 100] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 06/27/2017] [Indexed: 01/04/2023] Open
Abstract
Ergosterol, an important component of the fungal cell membrane, is not only essential for fungal growth and development but also very important for adaptation to stress in fungi. Ergosterol is also a direct precursor for steroid drugs. The biosynthesis of ergosterol can be divided into three modules: mevalonate, farnesyl pyrophosphate (farnesyl-PP) and ergosterol biosynthesis. The regulation of ergosterol content is mainly achieved by feedback regulation of ergosterol synthase activity through transcription, translation and posttranslational modification. The synthesis of HMG-CoA, catalyzed by HMGR, is a major metabolic check point in ergosterol biosynthesis. Excessive sterols can be subsequently stored in lipid droplets or secreted into the extracellular milieu by esterification or acetylation to avoid toxic effects. As sterols are insoluble, the intracellular transport of ergosterol in cells requires transporters. In recent years, great progress has been made in understanding ergosterol biosynthesis and its regulation in Saccharomyces cerevisiae. However, few reviews have focused on these studies, especially the regulation of biosynthesis and intracellular transport. Therefore, this review summarizes recent research progress on the physiological functions, biosynthesis, regulation of biosynthesis and intracellular transportation of ergosterol in S. cerevisiae.
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21
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Adelantado N, Tarazona P, Grillitsch K, García-Ortega X, Monforte S, Valero F, Feussner I, Daum G, Ferrer P. The effect of hypoxia on the lipidome of recombinant Pichia pastoris. Microb Cell Fact 2017; 16:86. [PMID: 28526017 PMCID: PMC5437588 DOI: 10.1186/s12934-017-0699-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 05/10/2017] [Indexed: 01/17/2023] Open
Abstract
Background Cultivation of recombinant Pichia pastoris (Komagataella sp.) under hypoxic conditions has a strong positive effect on specific productivity when the glycolytic GAP promoter is used for recombinant protein expression, mainly due to upregulation of glycolytic conditions. In addition, transcriptomic analyses of hypoxic P. pastoris pointed out important regulation of lipid metabolism and unfolded protein response (UPR). Notably, UPR that plays a role in the regulation of lipid metabolism, amino acid metabolism and protein secretion, was found to be upregulated under hypoxia. Results To improve our understanding of the interplay between lipid metabolism, UPR and protein secretion, the lipidome of a P. pastoris strain producing an antibody fragment was studied under hypoxic conditions. Furthermore, lipid composition analyses were combined with previously available transcriptomic datasets to further understand the impact of hypoxia on lipid metabolism. Chemostat cultures operated under glucose-limiting conditions under normoxic and hypoxic conditions were analyzed in terms of intra/extracellular product distribution and lipid composition. Integrated analysis of lipidome and transcriptome datasets allowed us to demonstrate an important remodeling of the lipid metabolism under limited oxygen availability. Additionally, cells with reduced amounts of ergosterol through fluconazole treatment were also included in the study to observe the impact on protein secretion and its lipid composition. Conclusions Our results show that cells adjust their membrane composition in response to oxygen limitation mainly by changing their sterol and sphingolipid composition. Although fluconazole treatment results a different lipidome profile than hypoxia, both conditions result in higher recombinant protein secretion levels. Electronic supplementary material The online version of this article (doi:10.1186/s12934-017-0699-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Núria Adelantado
- Department of Chemical, Biological and Environmental Engineering, Escola d'Enginyeria, Universitat Autònoma de Barcelona, Bellaterra, 08193, Barcelona, Catalonia, Spain.,Evonik Nutrition & Care GmbH, Hanau, Germany
| | - Pablo Tarazona
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University, Justus-von-Liebig-Weg 11, 37077, Göttingen, Germany
| | - Karlheinz Grillitsch
- Austrian Centre of Industrial Biotechnology (ACIB), Graz, Austria.,Institute of Biochemistry, Graz University of Technology, Petersgasse 12/II, 8010, Graz, Austria
| | - Xavier García-Ortega
- Department of Chemical, Biological and Environmental Engineering, Escola d'Enginyeria, Universitat Autònoma de Barcelona, Bellaterra, 08193, Barcelona, Catalonia, Spain
| | - Sergi Monforte
- Department of Chemical, Biological and Environmental Engineering, Escola d'Enginyeria, Universitat Autònoma de Barcelona, Bellaterra, 08193, Barcelona, Catalonia, Spain
| | - Francisco Valero
- Department of Chemical, Biological and Environmental Engineering, Escola d'Enginyeria, Universitat Autònoma de Barcelona, Bellaterra, 08193, Barcelona, Catalonia, Spain
| | - Ivo Feussner
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University, Justus-von-Liebig-Weg 11, 37077, Göttingen, Germany.,Department of Plant Biochemistry, Göttingen Center for Molecular Biosciences (GZMB), Georg-August-University, Justus-von-Liebig-Weg 11, 37077, Göttingen, Germany
| | - Günther Daum
- Austrian Centre of Industrial Biotechnology (ACIB), Graz, Austria. .,Institute of Biochemistry, Graz University of Technology, Petersgasse 12/II, 8010, Graz, Austria.
| | - Pau Ferrer
- Department of Chemical, Biological and Environmental Engineering, Escola d'Enginyeria, Universitat Autònoma de Barcelona, Bellaterra, 08193, Barcelona, Catalonia, Spain
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22
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Lipid engineering reveals regulatory roles for membrane fluidity in yeast flocculation and oxygen-limited growth. Metab Eng 2017; 41:46-56. [DOI: 10.1016/j.ymben.2017.03.002] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 02/10/2017] [Accepted: 03/08/2017] [Indexed: 12/20/2022]
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23
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Joshua IM, Höfken T. From Lipid Homeostasis to Differentiation: Old and New Functions of the Zinc Cluster Proteins Ecm22, Upc2, Sut1 and Sut2. Int J Mol Sci 2017; 18:ijms18040772. [PMID: 28379181 PMCID: PMC5412356 DOI: 10.3390/ijms18040772] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 03/27/2017] [Accepted: 03/31/2017] [Indexed: 12/27/2022] Open
Abstract
Zinc cluster proteins are a large family of transcriptional regulators with a wide range of biological functions. The zinc cluster proteins Ecm22, Upc2, Sut1 and Sut2 have initially been identified as regulators of sterol import in the budding yeast Saccharomyces cerevisiae. These proteins also control adaptations to anaerobic growth, sterol biosynthesis as well as filamentation and mating. Orthologs of these zinc cluster proteins have been identified in several species of Candida. Upc2 plays a critical role in antifungal resistance in these important human fungal pathogens. Upc2 is therefore an interesting potential target for novel antifungals. In this review we discuss the functions, mode of actions and regulation of Ecm22, Upc2, Sut1 and Sut2 in budding yeast and Candida.
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Affiliation(s)
| | - Thomas Höfken
- Division of Biosciences, Brunel University London, Uxbridge UB8 3PH, UK.
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24
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Dhingra S, Cramer RA. Regulation of Sterol Biosynthesis in the Human Fungal Pathogen Aspergillus fumigatus: Opportunities for Therapeutic Development. Front Microbiol 2017; 8:92. [PMID: 28203225 PMCID: PMC5285346 DOI: 10.3389/fmicb.2017.00092] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 01/13/2017] [Indexed: 12/29/2022] Open
Abstract
Sterols are a major component of eukaryotic cell membranes. For human fungal infections caused by the filamentous fungus Aspergillus fumigatus, antifungal drugs that target sterol biosynthesis and/or function remain the standard of care. Yet, an understanding of A. fumigatus sterol biosynthesis regulatory mechanisms remains an under developed therapeutic target. The critical role of sterol biosynthesis regulation and its interactions with clinically relevant azole drugs is highlighted by the basic helix loop helix (bHLH) class of transcription factors known as Sterol Regulatory Element Binding Proteins (SREBPs). SREBPs regulate transcription of key ergosterol biosynthesis genes in fungi including A. fumigatus. In addition, other emerging regulatory pathways and target genes involved in sterol biosynthesis and drug interactions provide additional opportunities including the unfolded protein response, iron responsive transcriptional networks, and chaperone proteins such as Hsp90. Thus, targeting molecular pathways critical for sterol biosynthesis regulation presents an opportunity to improve therapeutic options for the collection of diseases termed aspergillosis. This mini-review summarizes our current understanding of sterol biosynthesis regulation with a focus on mechanisms of transcriptional regulation by the SREBP family of transcription factors.
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Affiliation(s)
- Sourabh Dhingra
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover NH, USA
| | - Robert A Cramer
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover NH, USA
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25
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Time-Course Analysis of Gene Expression During the Saccharomyces cerevisiae Hypoxic Response. G3-GENES GENOMES GENETICS 2017; 7:221-231. [PMID: 27883312 PMCID: PMC5217111 DOI: 10.1534/g3.116.034991] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Many cells experience hypoxia, or low oxygen, and respond by dramatically altering gene expression. In the yeast Saccharomyces cerevisiae, genes that respond are required for many oxygen-dependent cellular processes, such as respiration, biosynthesis, and redox regulation. To more fully characterize the global response to hypoxia, we exposed yeast to hypoxic conditions, extracted RNA at different times, and performed RNA sequencing (RNA-seq) analysis. Time-course statistical analysis revealed hundreds of genes that changed expression by up to 550-fold. The genes responded with varying kinetics suggesting that multiple regulatory pathways are involved. We identified most known oxygen-regulated genes and also uncovered new regulated genes. Reverse transcription-quantitative PCR (RT-qPCR) analysis confirmed that the lysine methyltransferase EFM6 and the recombinase DMC1, both conserved in humans, are indeed oxygen-responsive. Looking more broadly, oxygen-regulated genes participate in expected processes like respiration and lipid metabolism, but also in unexpected processes like amino acid and vitamin metabolism. Using principle component analysis, we discovered that the hypoxic response largely occurs during the first 2 hr and then a new steady-state expression state is achieved. Moreover, we show that the oxygen-dependent genes are not part of the previously described environmental stress response (ESR) consisting of genes that respond to diverse types of stress. While hypoxia appears to cause a transient stress, the hypoxic response is mostly characterized by a transition to a new state of gene expression. In summary, our results reveal that hypoxia causes widespread and complex changes in gene expression to prepare the cell to function with little or no oxygen.
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26
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DuBois JC, Smulian AG. Sterol Regulatory Element Binding Protein (Srb1) Is Required for Hypoxic Adaptation and Virulence in the Dimorphic Fungus Histoplasma capsulatum. PLoS One 2016; 11:e0163849. [PMID: 27711233 PMCID: PMC5053422 DOI: 10.1371/journal.pone.0163849] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2015] [Accepted: 09/08/2016] [Indexed: 01/12/2023] Open
Abstract
The Histoplasma capsulatum sterol regulatory element binding protein (SREBP), Srb1 is a member of the basic helix-loop-helix (bHLH), leucine zipper DNA binding protein family of transcription factors that possess a unique tyrosine (Y) residue instead of an arginine (R) residue in the bHLH region. We have determined that Srb1 message levels increase in a time dependent manner during growth under oxygen deprivation (hypoxia). To further understand the role of Srb1 during infection and hypoxia, we silenced the gene encoding Srb1 using RNA interference (RNAi); characterized the resulting phenotype, determined its response to hypoxia, and its ability to cause disease within an infected host. Silencing of Srb1 resulted in a strain of H. capsulatum that is incapable of surviving in vitro hypoxia. We found that without complete Srb1 expression, H. capsulatum is killed by murine macrophages and avirulent in mice given a lethal dose of yeasts. Additionally, silencing Srb1 inhibited the hypoxic upregulation of other known H. capsulatum hypoxia-responsive genes (HRG), and genes that encode ergosterol biosynthetic enzymes. Consistent with these regulatory functions, Srb1 silenced H. capsulatum cells were hypersensitive to the antifungal azole drug itraconazole. These data support the theory that the H. capsulatum SREBP is critical for hypoxic adaptation and is required for H. capsulatum virulence.
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Affiliation(s)
- Juwen C. DuBois
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, Ohio, United States of America
- Cincinnati VA Medical Center, Cincinnati, Ohio, United States of America
| | - A. George Smulian
- Cincinnati VA Medical Center, Cincinnati, Ohio, United States of America
- Department of Internal Medicine, University of Cincinnati, Cincinnati, Ohio, United States of America
- * E-mail:
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27
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Hagiwara D, Sakamoto K, Abe K, Gomi K. Signaling pathways for stress responses and adaptation in Aspergillus species: stress biology in the post-genomic era. Biosci Biotechnol Biochem 2016; 80:1667-80. [PMID: 27007956 DOI: 10.1080/09168451.2016.1162085] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Aspergillus species are among the most important filamentous fungi in terms of industrial use and because of their pathogenic or toxin-producing features. The genomes of several Aspergillus species have become publicly available in this decade, and genomic analyses have contributed to an integrated understanding of fungal biology. Stress responses and adaptation mechanisms have been intensively investigated using the accessible genome infrastructure. Mitogen-activated protein kinase (MAPK) cascades have been highlighted as being fundamentally important in fungal adaptation to a wide range of stress conditions. Reverse genetics analyses have uncovered the roles of MAPK pathways in osmotic stress, cell wall stress, development, secondary metabolite production, and conidia stress resistance. This review summarizes the current knowledge on the stress biology of Aspergillus species, illuminating what we have learned from the genomic data in this "post-genomic era."
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Affiliation(s)
- Daisuke Hagiwara
- a Medical Mycology Research Center , Chiba University , Chiba , Japan
| | | | - Keietsu Abe
- c Graduate School of Agricultural Science , Tohoku University , Sendai , Japan
| | - Katsuya Gomi
- c Graduate School of Agricultural Science , Tohoku University , Sendai , Japan
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28
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Woods K, Höfken T. The zinc cluster proteins Upc2 and Ecm22 promote filamentation in Saccharomyces cerevisiae by sterol biosynthesis-dependent and -independent pathways. Mol Microbiol 2015; 99:512-27. [PMID: 26448198 DOI: 10.1111/mmi.13244] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/06/2015] [Indexed: 12/31/2022]
Abstract
The transition between a unicellular yeast form to multicellular filaments is crucial for budding yeast foraging and the pathogenesis of many fungal pathogens such as Candida albicans. Here, we examine the role of the related transcription factors Ecm22 and Upc2 in Saccharomyces cerevisiae filamentation. Overexpression of either ECM22 or UPC2 leads to increased filamentation, whereas cells lacking both ECM22 and UPC2 do not exhibit filamentous growth. Ecm22 and Upc2 positively control the expression of FHN1, NPR1, PRR2 and sterol biosynthesis genes. These genes all play a positive role in filamentous growth, and their expression is upregulated during filamentation in an Ecm22/Upc2-dependent manner. Furthermore, ergosterol content increases during filamentous growth. UPC2 expression also increases during filamentation and is inhibited by the transcription factors Sut1 and Sut2. The expression of SUT1 and SUT2 in turn is under negative control of the transcription factor Ste12. We suggest that during filamentation Ste12 becomes activated and reduces SUT1/SUT2 expression levels. This would result in increased UPC2 levels and as a consequence to transcriptional activation of FHN1, NPR1, PRR2 and sterol biosynthesis genes. Higher ergosterol levels in combination with the proteins Fhn1, Npr1 and Prr2 would then mediate the transition to filamentous growth.
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Affiliation(s)
- Kelly Woods
- Division of Biosciences, Brunel University London, Uxbridge, UK
| | - Thomas Höfken
- Division of Biosciences, Brunel University London, Uxbridge, UK
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29
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DuBois JC, Pasula R, Dade JE, Smulian AG. Yeast Transcriptome and In Vivo Hypoxia Detection Reveals Histoplasma capsulatum Response to Low Oxygen Tension. Med Mycol 2015; 54:40-58. [PMID: 26483436 DOI: 10.1093/mmy/myv073] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2015] [Accepted: 07/13/2015] [Indexed: 12/24/2022] Open
Abstract
Although there is growing understanding of the microenvironmental conditions fungal pathogens encounter as they colonize their host, nothing is known about Histoplasma capsulatum's response to hypoxia. Here we characterized hypoxia during murine histoplasmosis using an in vivo hypoxia detection agent, Hypoxyprobe-2 (HP-2); and analyzed H. capsulatum's transcriptional profile in response to in vitro hypoxia. Immunohistopathology and flow cytometry analyses revealed distinct regions of hypoxia during infection. Granuloma cells, enriched with macrophages and T-cells isolated from infected livers were 66-76% positive for HP-2, of which, 95% of macrophages and 55% of T-cells were hypoxic. Although inhibited, H. capsulatum was able to survive under in vitro hypoxic conditions (<1% O2), and restored growth when replaced in normoxia. Next-generation sequencing (RNA-seq) analysis after 24 hours of hypoxia demonstrated a significant increase in NIT50 (swirm domain DNA binding protein), a predicted ABC transporter (ABC), NADPH oxidoreductase (NADP/FAD), and guanine nucleotide exchange factor (RSP/GEF); and other genes with no known designated function. Computational transcription factor binding site analysis predicted human sterol regulatory element binding protein (SREBP) binding sites upstream of NIT50, ABC, NADP/FAD and RSP/GEF. Hypoxia resulted in a time-dependent increase in the H. capsulatum homolog of SREBP, here named Srb1. Srb1 peaked at 8 hours and returned to basal levels by 24 hours. Our findings demonstrate that H. capsulatum encounters and survives severe hypoxia during infection. Additionally, the hypoxic response may be regulated at the level of transcription, and these studies contribute to the understanding of hypoxic regulation and adaptation in H. capsulatum.
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Affiliation(s)
- Juwen C DuBois
- Department of Pathology and Laboratory Medicine
- Cincinnati VA Medical Center, Cincinnati Ohio
| | - Rajamouli Pasula
- Department of Internal Medicine, University of Cincinnati, Cincinnati Ohio
- Cincinnati VA Medical Center, Cincinnati Ohio
| | - Jessica E Dade
- Department of Internal Medicine, University of Cincinnati, Cincinnati Ohio
- Cincinnati VA Medical Center, Cincinnati Ohio
| | - A George Smulian
- Department of Internal Medicine, University of Cincinnati, Cincinnati Ohio
- Cincinnati VA Medical Center, Cincinnati Ohio
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30
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Castelblanco-Matiz LM, Barbachano-Torres A, Ponce-Noyola T, Ramos-Valdivia AC, Cerda García-Rojas CM, Flores-Ortiz CM, Barahona-Crisóstomo SK, Baeza-Cancino ME, Alcaíno-Gorman J, Cifuentes-Guzmán VH. Carotenoid production and gene expression in an astaxanthin-overproducing Xanthophyllomyces dendrorhous mutant strain. Arch Microbiol 2015; 197:1129-39. [DOI: 10.1007/s00203-015-1153-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Revised: 08/07/2015] [Accepted: 09/11/2015] [Indexed: 12/25/2022]
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31
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Ottaviano D, Montanari A, De Angelis L, Santomartino R, Visca A, Brambilla L, Rinaldi T, Bello C, Reverberi M, Bianchi MM. Unsaturated fatty acids-dependent linkage between respiration and fermentation revealed by deletion of hypoxic regulatory KlMGA2 gene in the facultative anaerobe-respiratory yeast Kluyveromyces lactis. FEMS Yeast Res 2015; 15:fov028. [PMID: 26019145 DOI: 10.1093/femsyr/fov028] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/17/2015] [Indexed: 01/03/2023] Open
Abstract
In the yeast Kluyveromyces lactis, the inactivation of structural or regulatory glycolytic and fermentative genes generates obligate respiratory mutants which can be characterized by sensitivity to the mitochondrial drug antimycin A on glucose medium (Rag(-) phenotype). Rag(-) mutations can occasionally be generated by the inactivation of genes not evidently related to glycolysis or fermentation. One such gene is the hypoxic regulatory gene KlMGA2. In this work, we report a study of the many defects, in addition to the Rag(-) phenotype, generated by KlMGA2 deletion. We analyzed the fermentative and respiratory metabolism, mitochondrial functioning and morphology in the Klmga2Δ strain. We also examined alterations in the regulation of the expression of lipid biosynthetic genes, in particular fatty acids, ergosterol and cardiolipin, under hypoxic and cold stress and the phenotypic suppression by unsaturated fatty acids of the deleted strain. Results indicate that, despite the fact that the deleted mutant strain had a typical glycolytic/fermentative phenotype and KlMGA2 is a hypoxic regulatory gene, the deletion of this gene generated defects linked to mitochondrial functions suggesting new roles of this protein in the general regulation and cellular fitness of K. lactis. Supplementation of unsaturated fatty acids suppressed or modified these defects suggesting that KlMga2 modulates membrane functioning or membrane-associated functions, both cytoplasmic and mitochondrial.
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Affiliation(s)
- Daniela Ottaviano
- Department of Biology and Biotechnology 'Charles Darwin', Sapienza University of Rome, p.le Aldo Moro 5, 00185 Rome, Italy
| | - Arianna Montanari
- Department of Biology and Biotechnology 'Charles Darwin', Sapienza University of Rome, p.le Aldo Moro 5, 00185 Rome, Italy
| | - Lorenzo De Angelis
- Department of Biology and Biotechnology 'Charles Darwin', Sapienza University of Rome, p.le Aldo Moro 5, 00185 Rome, Italy
| | - Rosa Santomartino
- Department of Biology and Biotechnology 'Charles Darwin', Sapienza University of Rome, p.le Aldo Moro 5, 00185 Rome, Italy
| | - Andrea Visca
- Department of Biology and Biotechnology 'Charles Darwin', Sapienza University of Rome, p.le Aldo Moro 5, 00185 Rome, Italy
| | - Luca Brambilla
- Department of Biotechnology and Biosciences, Bicocca University of Milan, p.zza Della Scienza 2, 20126 Milan, Italy
| | - Teresa Rinaldi
- Department of Biology and Biotechnology 'Charles Darwin', Sapienza University of Rome, p.le Aldo Moro 5, 00185 Rome, Italy Pasteur Institut Cenci-Bolognetti Foundation, p.le Aldo Moro 5, 00185 Rome, Italy
| | - Cristiano Bello
- Departement of Environmental Biology, Sapienza University of Rome, p.le Aldo Moro 5, 00185 Rome, Italy
| | - Massimo Reverberi
- Departement of Environmental Biology, Sapienza University of Rome, p.le Aldo Moro 5, 00185 Rome, Italy
| | - Michele M Bianchi
- Department of Biology and Biotechnology 'Charles Darwin', Sapienza University of Rome, p.le Aldo Moro 5, 00185 Rome, Italy
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Platt FM, Wassif C, Colaco A, Dardis A, Lloyd-Evans E, Bembi B, Porter FD. Disorders of cholesterol metabolism and their unanticipated convergent mechanisms of disease. Annu Rev Genomics Hum Genet 2015; 15:173-94. [PMID: 25184529 DOI: 10.1146/annurev-genom-091212-153412] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Cholesterol plays a key role in many cellular processes, and is generated by cells through de novo biosynthesis or acquired from exogenous sources through the uptake of low-density lipoproteins. Cholesterol biosynthesis is a complex, multienzyme-catalyzed pathway involving a series of sequentially acting enzymes. Inherited defects in genes encoding cholesterol biosynthetic enzymes or other regulators of cholesterol homeostasis result in severe metabolic diseases, many of which are rare in the general population and currently without effective therapy. Historically, these diseases have been viewed as discrete disorders, each with its own genetic cause and distinct pathogenic cascades that lead to its specific clinical features. However, studies have recently shown that three of these diseases have an unanticipated mechanistic convergence. This surprising finding is not only shedding light on details of cellular cholesterol homeostasis but also suggesting novel approaches to therapy.
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Affiliation(s)
- Frances M Platt
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom;
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33
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Yang W, Catalanotti C, Wittkopp TM, Posewitz MC, Grossman AR. Algae after dark: mechanisms to cope with anoxic/hypoxic conditions. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2015; 82:481-503. [PMID: 25752440 DOI: 10.1111/tpj.12823] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 02/28/2015] [Accepted: 03/03/2015] [Indexed: 06/04/2023]
Abstract
Chlamydomonas reinhardtii is a unicellular, soil-dwelling (and aquatic) green alga that has significant metabolic flexibility for balancing redox equivalents and generating ATP when it experiences hypoxic/anoxic conditions. The diversity of pathways available to ferment sugars is often revealed in mutants in which the activities of specific branches of fermentative metabolism have been eliminated; compensatory pathways that have little activity in parental strains under standard laboratory fermentative conditions are often activated. The ways in which these pathways are regulated and integrated have not been extensively explored. In this review, we primarily discuss the intricacies of dark anoxic metabolism in Chlamydomonas, but also discuss aspects of dark oxic metabolism, the utilization of acetate, and the relatively uncharacterized but critical interactions that link chloroplastic and mitochondrial metabolic networks.
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Affiliation(s)
- Wenqiang Yang
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, 94305, USA
| | - Claudia Catalanotti
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, 94305, USA
| | - Tyler M Wittkopp
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, 94305, USA
- Department of Biology, Stanford University, Stanford, CA, 94305, USA
| | - Matthew C Posewitz
- Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, CO, 80401, USA
| | - Arthur R Grossman
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, 94305, USA
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34
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Emmerstorfer A, Wimmer-Teubenbacher M, Wriessnegger T, Leitner E, Müller M, Kaluzna I, Schürmann M, Mink D, Zellnig G, Schwab H, Pichler H. Over-expression ofICE2stabilizes cytochrome P450 reductase inSaccharomyces cerevisiaeandPichia pastoris. Biotechnol J 2015; 10:623-35. [DOI: 10.1002/biot.201400780] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Revised: 12/17/2014] [Accepted: 01/09/2015] [Indexed: 01/15/2023]
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ChIP-seq and in vivo transcriptome analyses of the Aspergillus fumigatus SREBP SrbA reveals a new regulator of the fungal hypoxia response and virulence. PLoS Pathog 2014; 10:e1004487. [PMID: 25375670 PMCID: PMC4223079 DOI: 10.1371/journal.ppat.1004487] [Citation(s) in RCA: 133] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Accepted: 09/23/2014] [Indexed: 12/21/2022] Open
Abstract
The Aspergillus fumigatus sterol regulatory element binding protein (SREBP) SrbA belongs to the basic Helix-Loop-Helix (bHLH) family of transcription factors and is crucial for antifungal drug resistance and virulence. The latter phenotype is especially striking, as loss of SrbA results in complete loss of virulence in murine models of invasive pulmonary aspergillosis (IPA). How fungal SREBPs mediate fungal virulence is unknown, though it has been suggested that lack of growth in hypoxic conditions accounts for the attenuated virulence. To further understand the role of SrbA in fungal infection site pathobiology, chromatin immunoprecipitation followed by massively parallel DNA sequencing (ChIP-seq) was used to identify genes under direct SrbA transcriptional regulation in hypoxia. These results confirmed the direct regulation of ergosterol biosynthesis and iron uptake by SrbA in hypoxia and revealed new roles for SrbA in nitrate assimilation and heme biosynthesis. Moreover, functional characterization of an SrbA target gene with sequence similarity to SrbA identified a new transcriptional regulator of the fungal hypoxia response and virulence, SrbB. SrbB co-regulates genes involved in heme biosynthesis and demethylation of C4-sterols with SrbA in hypoxic conditions. However, SrbB also has regulatory functions independent of SrbA including regulation of carbohydrate metabolism. Loss of SrbB markedly attenuates A. fumigatus virulence, and loss of both SREBPs further reduces in vivo fungal growth. These data suggest that both A. fumigatus SREBPs are critical for hypoxia adaptation and virulence and reveal new insights into SREBPs' complex role in infection site adaptation and fungal virulence. Despite improvements in diagnostics and antifungal drug treatments, mortality rates from invasive mold infections remain high. Defining the fungal adaptation and growth mechanisms at the infection site microenvironment is one research focus that is expected to improve treatment of established invasive fungal infections. The Aspergillus fumigatus transcription factor SrbA is a major regulator of the fungal response to hypoxia found at sites of invasive fungal growth in vivo. In this study, new insights into how SrbA mediates hypoxia adaptation and virulence were revealed through identification of direct transcriptional targets of SrbA under hypoxic conditions. A major novel finding from these studies is the identification of a critical role in fungal hypoxia adaptation and virulence of an SrbA target gene, srbB, which is also in the SREBP family. SrbB plays a major role in regulation of heme biosynthesis and carbohydrate metabolism early in the response to hypoxia. The discovery of SrbA-dependent regulation of srbB gene expression, and the target genes they regulate opens new avenues to understand how SREBPs and their target genes mediate adaptation to the in vivo infection site microenvironment and responses to current antifungal therapies.
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Klug L, Daum G. Yeast lipid metabolism at a glance. FEMS Yeast Res 2014; 14:369-88. [DOI: 10.1111/1567-1364.12141] [Citation(s) in RCA: 199] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 01/23/2014] [Accepted: 02/02/2014] [Indexed: 01/07/2023] Open
Affiliation(s)
- Lisa Klug
- Institute of Biochemistry; Graz University of Technology; Graz Austria
| | - Günther Daum
- Institute of Biochemistry; Graz University of Technology; Graz Austria
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Orellana M, Aceituno FF, Slater AW, Almonacid LI, Melo F, Agosin E. Metabolic and transcriptomic response of the wine yeast Saccharomyces cerevisiae strain EC1118 after an oxygen impulse under carbon-sufficient, nitrogen-limited fermentative conditions. FEMS Yeast Res 2014; 14:412-24. [PMID: 24387769 DOI: 10.1111/1567-1364.12135] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Revised: 12/09/2013] [Accepted: 12/29/2013] [Indexed: 11/27/2022] Open
Abstract
During alcoholic fermentation, Saccharomyces cerevisiae is exposed to continuously changing environmental conditions, such as decreasing sugar and increasing ethanol concentrations. Oxygen, a critical nutrient to avoid stuck and sluggish fermentations, is only discretely available throughout the process after pump-over operation. In this work, we studied the physiological response of the wine yeast S. cerevisiae strain EC1118 to a sudden increase in dissolved oxygen, simulating pump-over operation. With this aim, an impulse of dissolved oxygen was added to carbon-sufficient, nitrogen-limited anaerobic continuous cultures. Results showed that genes related to mitochondrial respiration, ergosterol biosynthesis, and oxidative stress, among other metabolic pathways, were induced after the oxygen impulse. On the other hand, mannoprotein coding genes were repressed. The changes in the expression of these genes are coordinated responses that share common elements at the level of transcriptional regulation. Beneficial and detrimental effects of these physiological processes on wine quality highlight the dual role of oxygen in 'making or breaking wines'. These findings will facilitate the development of oxygen addition strategies to optimize yeast performance in industrial fermentations.
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Affiliation(s)
- Marcelo Orellana
- Department of Chemical and Bioprocess Engineering, School of Engineering, Pontificia Universidad Católica de Chile, Macul, Santiago, Chile
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38
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Yucel EB, Eraslan S, Ulgen KO. The impact of medium acidity on the chronological life span ofSaccharomyces cerevisiae - lipids, signaling cascades, mitochondrial and vacuolar functions. FEBS J 2014; 281:1281-303. [DOI: 10.1111/febs.12705] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2013] [Revised: 12/20/2013] [Accepted: 12/23/2013] [Indexed: 12/18/2022]
Affiliation(s)
- Esra B. Yucel
- Department of Chemical Engineering; Boğaziçi University; Istanbul Turkey
| | - Serpil Eraslan
- Department of Chemical Engineering; Boğaziçi University; Istanbul Turkey
| | - Kutlu O. Ulgen
- Department of Chemical Engineering; Boğaziçi University; Istanbul Turkey
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Christadore LM, Pham L, Kolaczyk ED, Schaus SE. Improvement of experimental testing and network training conditions with genome-wide microarrays for more accurate predictions of drug gene targets. BMC SYSTEMS BIOLOGY 2014; 8:7. [PMID: 24444313 PMCID: PMC3911882 DOI: 10.1186/1752-0509-8-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Accepted: 11/21/2013] [Indexed: 11/10/2022]
Abstract
Background Genome-wide microarrays have been useful for predicting chemical-genetic interactions at the gene level. However, interpreting genome-wide microarray results can be overwhelming due to the vast output of gene expression data combined with off-target transcriptional responses many times induced by a drug treatment. This study demonstrates how experimental and computational methods can interact with each other, to arrive at more accurate predictions of drug-induced perturbations. We present a two-stage strategy that links microarray experimental testing and network training conditions to predict gene perturbations for a drug with a known mechanism of action in a well-studied organism. Results S. cerevisiae cells were treated with the antifungal, fluconazole, and expression profiling was conducted under different biological conditions using Affymetrix genome-wide microarrays. Transcripts were filtered with a formal network-based method, sparse simultaneous equation models and Lasso regression (SSEM-Lasso), under different network training conditions. Gene expression results were evaluated using both gene set and single gene target analyses, and the drug’s transcriptional effects were narrowed first by pathway and then by individual genes. Variables included: (i) Testing conditions – exposure time and concentration and (ii) Network training conditions – training compendium modifications. Two analyses of SSEM-Lasso output – gene set and single gene – were conducted to gain a better understanding of how SSEM-Lasso predicts perturbation targets. Conclusions This study demonstrates that genome-wide microarrays can be optimized using a two-stage strategy for a more in-depth understanding of how a cell manifests biological reactions to a drug treatment at the transcription level. Additionally, a more detailed understanding of how the statistical model, SSEM-Lasso, propagates perturbations through a network of gene regulatory interactions is achieved.
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Affiliation(s)
| | | | | | - Scott E Schaus
- Department of Chemistry, Boston University, Boston, MA, USA.
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40
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Chang J, Zhou Y, Hu X, Lam L, Henry C, Green EM, Kita R, Kobor MS, Fraser HB. The molecular mechanism of a cis-regulatory adaptation in yeast. PLoS Genet 2013; 9:e1003813. [PMID: 24068973 PMCID: PMC3778017 DOI: 10.1371/journal.pgen.1003813] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Accepted: 07/17/2013] [Indexed: 11/23/2022] Open
Abstract
Despite recent advances in our ability to detect adaptive evolution involving the cis-regulation of gene expression, our knowledge of the molecular mechanisms underlying these adaptations has lagged far behind. Across all model organisms, the causal mutations have been discovered for only a handful of gene expression adaptations, and even for these, mechanistic details (e.g. the trans-regulatory factors involved) have not been determined. We previously reported a polygenic gene expression adaptation involving down-regulation of the ergosterol biosynthesis pathway in the budding yeast Saccharomyces cerevisiae. Here we investigate the molecular mechanism of a cis-acting mutation affecting a member of this pathway, ERG28. We show that the causal mutation is a two-base deletion in the promoter of ERG28 that strongly reduces the binding of two transcription factors, Sok2 and Mot3, thus abolishing their regulation of ERG28. This down-regulation increases resistance to a widely used antifungal drug targeting ergosterol, similar to mutations disrupting this pathway in clinical yeast isolates. The identification of the causal genetic variant revealed that the selection likely occurred after the deletion was already present at high frequency in the population, rather than when it was a new mutation. These results provide a detailed view of the molecular mechanism of a cis-regulatory adaptation, and underscore the importance of this view to our understanding of evolution at the molecular level. Evolutionary adaptation is the process that has given rise to the ubiquitous, yet remarkable, fit between all living organisms and their environments. The molecular mechanisms of these adaptations have been a subject of great interest, but we still know very little about their mechanisms, particularly in the case of regulatory adaptations. In this work, we investigate the molecular mechanism of a regulatory adaptation that we previously identified in ERG28, a component of the ergosterol biosynthesis pathway in budding yeast. Ergosterol is an abundant lipid component of the fungal plasma membrane, and is of major biomedical importance, being targeted by numerous antifungal drugs. We identified the causal mutation underlying the ERG28 adaptation, a two-base deletion in its promoter which leads to lower abundance of its mRNA. This deletion acts via disrupting the binding of at least two transcription factors, Mot3 and Sok2, to the promoter. The deletion increases resistance to a widely used antifungal drug, Amphotericin B, which targets ergosterol. This effect is reminiscent of misregulation of the ergosterol pathway observed in clinical yeast isolates that have evolved resistance to Amphotericin B. Our results may therefore have medical implications, while also advancing our basic understanding of evolutionary mechanisms.
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Affiliation(s)
- Jessica Chang
- Department of Biology, Stanford University, Stanford , California, United States of America
| | - Yiqi Zhou
- Department of Biology, Stanford University, Stanford , California, United States of America
| | - Xiaoli Hu
- Department of Biology, Stanford University, Stanford , California, United States of America
| | - Lucia Lam
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Vancouver, British Columbia, Canada
| | - Cameron Henry
- Department of Biology, Stanford University, Stanford , California, United States of America
| | - Erin M. Green
- Department of Biology, Stanford University, Stanford , California, United States of America
| | - Ryosuke Kita
- Department of Biology, Stanford University, Stanford , California, United States of America
| | - Michael S. Kobor
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Vancouver, British Columbia, Canada
| | - Hunter B. Fraser
- Department of Biology, Stanford University, Stanford , California, United States of America
- * E-mail:
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Abstract
The response of eukaryotic microbes to low-oxygen (hypoxic) conditions is strongly regulated at the level of transcription. Comparative analysis shows that some of the transcriptional regulators (such as the sterol regulatory element-binding proteins, or SREBPs) are of ancient origin and probably regulate sterol synthesis in most eukaryotic microbes. However, in some fungi SREBPs have been replaced by a zinc-finger transcription factor (Upc2). Nuclear localization of fungal SREBPs is determined by regulated proteolysis, either by site-specific proteases or by an E3 ligase complex and the proteasome. The exact mechanisms of oxygen sensing are not fully characterized but involve responding to low levels of heme and/or sterols and possibly to levels of nitric oxide and reactive oxygen species. Changes in central carbon metabolism (glycolysis and respiration) are a core hypoxic response in some, but not all, fungal species. Adaptation to hypoxia is an important virulence characteristic of pathogenic fungi.
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Affiliation(s)
- Geraldine Butler
- School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland;
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Comparison of sterol import under aerobic and anaerobic conditions in three fungal species, Candida albicans, Candida glabrata, and Saccharomyces cerevisiae. EUKARYOTIC CELL 2013; 12:725-38. [PMID: 23475705 DOI: 10.1128/ec.00345-12] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Sterol import has been characterized under various conditions in three distinct fungal species, the model organism Saccharomyces cerevisiae and two human fungal pathogens Candida glabrata and Candida albicans, employing cholesterol, the sterol of higher eukaryotes, as well as its fungal equivalent, ergosterol. Import was confirmed by the detection of esterified cholesterol within the cells. Comparing the three fungal species, we observe sterol import under three different conditions. First, as previously well characterized, we observe sterol import under low oxygen levels in S. cerevisiae and C. glabrata, which is dependent on the transcription factor Upc2 and/or its orthologs or paralogs. Second, we observe sterol import under aerobic conditions exclusively in the two pathogenic fungi C. glabrata and C. albicans. Uptake emerges during post-exponential-growth phases, is independent of the characterized Upc2-pathway and is slower compared to the anaerobic uptake in S. cerevisiae and C. glabrata. Third, we observe under normoxic conditions in C. glabrata that Upc2-dependent sterol import can be induced in the presence of fetal bovine serum together with fluconazole. In summary, C. glabrata imports sterols both in aerobic and anaerobic conditions, and the limited aerobic uptake can be further stimulated by the presence of serum together with fluconazole. S. cerevisiae imports sterols only in anaerobic conditions, demonstrating aerobic sterol exclusion. Finally, C. albicans imports sterols exclusively aerobically in post-exponential-growth phases, independent of Upc2. For the first time, we provide direct evidence of sterol import into the human fungal pathogen C. albicans, which until now was believed to be incapable of active sterol import.
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Fujiwara H, Kawai S, Murata K. Significance of sulfiredoxin/peroxiredoxin and mitochondrial respiratory chain in response to and protection from 100% O(2) in Saccharomyces cerevisiae. Mitochondrion 2013; 13:52-8. [PMID: 23291433 DOI: 10.1016/j.mito.2012.12.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Revised: 10/01/2012] [Accepted: 12/20/2012] [Indexed: 11/26/2022]
Abstract
The mechanisms underlying organisms respond to and protect from hyperoxia remain elusive. We establish a system for cultivating the yeast Saccharomyces cerevisiae cells in liquid medium under 100% O(2) and revealed that SRX1, encoding sulfiredoxin, is significantly induced by 100% O(2) dependently on transcription factors Yap1 and Skn7. Sulfiredoxin has a role in restoring the abundant peroxiredoxin, Tsa1. Tsa1 was indispensable for protection from 100% O(2) in the presence of antimycin A, an inhibitor of complex III in the mitochondrial respiratory chain, collectively emphasizing the significance of sulfiredoxin, peroxiredoxin, and mitochondrial respiratory chain to respond to and to protect from 100% O(2).
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Affiliation(s)
- Hiroki Fujiwara
- Laboratory of Basic and Applied Molecular Biotechnology, Division of Food and Biological Science, Graduate School of Agriculture, Kyoto University, Uji, Kyoto, Japan
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Chung D, Haas H, Cramer RA. Coordination of hypoxia adaptation and iron homeostasis in human pathogenic fungi. Front Microbiol 2012; 3:381. [PMID: 23133438 PMCID: PMC3490150 DOI: 10.3389/fmicb.2012.00381] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2012] [Accepted: 10/11/2012] [Indexed: 12/11/2022] Open
Abstract
In mammals, hypoxia causes facilitated erythropoiesis that requires increased iron availability with established links between oxygen and iron in regulation of the transcription factor hypoxia-inducible factor. Therefore, cellular responses to hypoxia and iron starvation are linked in mammals and are host conditions that pathogens encounter during infection. In human pathogenic fungi, molecular mechanisms underlying hypoxia adaptation and iron homeostasis have been investigated. However, the interconnected regulation of hypoxia adaptation and iron homeostasis remains to be fully elucidated. This review discusses the potential transcriptional regulatory links between hypoxia adaptation and iron homeostasis in human pathogenic fungi. Transcriptome analyses demonstrate that core regulators of hypoxia adaptation and iron homeostasis are involved in regulation of several common genes responsible for iron acquisition and ergosterol biosynthesis. Importantly, iron starvation increases susceptibility of fungal cells to antifungal drugs and decreased levels of ergosterol, while key hypoxia regulators are also involved in responses to antifungal drugs and mediating ergosterol levels. We suggest that pathogenic fungi have developed a coordinated regulatory system in response to hypoxia and iron starvation through (i) regulation of expression of hypoxia-responsive and iron-responsive genes via cross-linked key regulators, and/or (ii) regulation of factors involved in ergosterol biosynthesis. Thus, both oxygen and iron availability are intimately tied with fungal virulence and responses to existing therapeutics and further elucidation of their interrelationship should have significant clinical implications.
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Affiliation(s)
- Dawoon Chung
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth Hanover, NH, USA
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Siso MIG, Becerra M, Maceiras ML, Vázquez ÁV, Cerdán ME. The yeast hypoxic responses, resources for new biotechnological opportunities. Biotechnol Lett 2012; 34:2161-73. [DOI: 10.1007/s10529-012-1039-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Accepted: 08/14/2012] [Indexed: 10/27/2022]
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Oxygen response of the wine yeast Saccharomyces cerevisiae EC1118 grown under carbon-sufficient, nitrogen-limited enological conditions. Appl Environ Microbiol 2012; 78:8340-52. [PMID: 23001663 DOI: 10.1128/aem.02305-12] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Discrete additions of oxygen play a critical role in alcoholic fermentation. However, few studies have quantitated the fate of dissolved oxygen and its impact on wine yeast cell physiology under enological conditions. We simulated the range of dissolved oxygen concentrations that occur after a pump-over during the winemaking process by sparging nitrogen-limited continuous cultures with oxygen-nitrogen gaseous mixtures. When the dissolved oxygen concentration increased from 1.2 to 2.7 μM, yeast cells changed from a fully fermentative to a mixed respirofermentative metabolism. This transition is characterized by a switch in the operation of the tricarboxylic acid cycle (TCA) and an activation of NADH shuttling from the cytosol to mitochondria. Nevertheless, fermentative ethanol production remained the major cytosolic NADH sink under all oxygen conditions, suggesting that the limitation of mitochondrial NADH reoxidation is the major cause of the Crabtree effect. This is reinforced by the induction of several key respiratory genes by oxygen, despite the high sugar concentration, indicating that oxygen overrides glucose repression. Genes associated with other processes, such as proline uptake, cell wall remodeling, and oxidative stress, were also significantly affected by oxygen. The results of this study indicate that respiration is responsible for a substantial part of the oxygen response in yeast cells during alcoholic fermentation. This information will facilitate the development of temporal oxygen addition strategies to optimize yeast performance in industrial fermentations.
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Gain-of-function mutations in UPC2 are a frequent cause of ERG11 upregulation in azole-resistant clinical isolates of Candida albicans. EUKARYOTIC CELL 2012; 11:1289-99. [PMID: 22923048 DOI: 10.1128/ec.00215-12] [Citation(s) in RCA: 151] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
In Candida albicans, Upc2 is a zinc-cluster transcription factor that targets genes, including those of the ergosterol biosynthesis pathway. To date, three documented UPC2 gain-of-function (GOF) mutations have been recovered from fluconazole-resistant clinical isolates that contribute to an increase in ERG11 expression and decreased fluconazole susceptibility. In a group of 63 isolates with reduced susceptibility to fluconazole, we found that 47 overexpressed ERG11 by at least 2-fold over the average expression levels in 3 unrelated fluconazole-susceptible strains. Of those 47 isolates, 29 contained a mutation in UPC2, whereas the remaining 18 isolates did not. Among the isolates containing mutations in UPC2, we recovered eight distinct mutations resulting in putative single amino acid substitutions: G648D, G648S, A643T, A643V, Y642F, G304R, A646V, and W478C. Seven of these resulted in increased ERG11 expression, increased cellular ergosterol, and decreased susceptibility to fluconazole compared to the results for the wild-type strain. Genome-wide transcriptional analysis was performed for the four strongest Upc2 amino acid substitutions (A643V, G648D, G648S, and Y642F). Genes commonly upregulated by all four mutations included those involved in ergosterol biosynthesis, in oxidoreductase activity, the major facilitator efflux pump encoded by the MDR1 gene, and the uncharacterized ATP binding cassette transporter CDR11. These findings demonstrate that gain-of-function mutations in UPC2 are more prevalent among clinical isolates than previously thought and make a significant contribution to azole antifungal resistance, but the findings do not account for ERG11 overexpression in all such isolates of C. albicans.
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Dümcke S, Seizl M, Etzold S, Pirkl N, Martin DE, Cramer P, Tresch A. One Hand Clapping: detection of condition-specific transcription factor interactions from genome-wide gene activity data. Nucleic Acids Res 2012; 40:8883-92. [PMID: 22844089 PMCID: PMC3467085 DOI: 10.1093/nar/gks695] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
We present One Hand Clapping (OHC), a method for the detection of condition-specific interactions between transcription factors (TFs) from genome-wide gene activity measurements. OHC is based on a mapping between transcription factors and their target genes. Given a single case–control experiment, it uses a linear regression model to assess whether the common targets of two arbitrary TFs behave differently than expected from the genes targeted by only one of the TFs. When applied to osmotic stress data in S. cerevisiae, OHC produces consistent results across three types of expression measurements: gene expression microarray data, RNA Polymerase II ChIP-chip binding data and messenger RNA synthesis rates. Among the eight novel, condition-specific TF pairs, we validate the interaction between Gcn4p and Arr1p experimentally. We apply OHC to a large gene activity dataset in S. cerevisiae and provide a compendium of condition-specific TF interactions.
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Affiliation(s)
- Sebastian Dümcke
- Gene Center Munich and Department of Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Straße 25, 81377 Munich, Germany
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Kluyveromyces lactis: a suitable yeast model to study cellular defense mechanisms against hypoxia-induced oxidative stress. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2012; 2012:634674. [PMID: 22928082 PMCID: PMC3425888 DOI: 10.1155/2012/634674] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Accepted: 06/22/2012] [Indexed: 11/17/2022]
Abstract
Studies about hypoxia-induced oxidative stress in human health disorders take advantage from the use of unicellular eukaryote models. A widely extended model is the fermentative yeast Saccharomyces cerevisiae. In this paper, we describe an overview of the molecular mechanisms induced by a decrease in oxygen availability and their interrelationship with the oxidative stress response in yeast. We focus on the differential characteristics between S. cerevisiae and the respiratory yeast Kluyveromyces lactis, a complementary emerging model, in reference to multicellular eukaryotes.
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Micolonghi C, Ottaviano D, Di Silvio E, Damato G, Heipieper HJ, Bianchi MM. A dual signalling pathway for the hypoxic expression of lipid genes, dependent on the glucose sensor Rag4, is revealed by the analysis of the KlMGA2 gene in Kluyveromyces lactis. MICROBIOLOGY-SGM 2012; 158:1734-1744. [PMID: 22516223 DOI: 10.1099/mic.0.059402-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
In the respiratory yeast Kluyveromyces lactis, little is known about the factors regulating the metabolic response to oxygen shortage. After searching for homologues of characterized Saccharomyces cerevisiae regulators of the hypoxic response, we identified a gene that we named KlMGA2, which is homologous to MGA2. The deletion of KlMGA2 strongly reduced both the fermentative and respiratory growth rate and altered fatty acid composition and the unsaturation index of membranes. The reciprocal heterologous expression of MGA2 and KlMGA2 in the corresponding deletion mutant strains suggested that Mga2 and KlMga2 are functional homologues. KlMGA2 transcription was induced by hypoxia and the glucose sensor Rag4 mediated the hypoxic induction of KlMGA2. Transcription of lipid biosynthetic genes KlOLE1, KlERG1, KlFAS1 and KlATF1 was induced by hypoxia and was dependent on KlMga2, except for KlOLE1. Rag4 was required for hypoxic induction of transcription for both KlMga2-dependent (KlERG1) and KlMga2-independent (KlOLE1) structural genes.
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Affiliation(s)
- Chiara Micolonghi
- Department of Biology and Biotechnology Charles Darwin, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy
| | - Daniela Ottaviano
- Department of Biology and Biotechnology Charles Darwin, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy
| | - Eva Di Silvio
- Department of Biology and Biotechnology Charles Darwin, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy
| | - Giuseppe Damato
- Department of Biology and Biotechnology Charles Darwin, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy
| | - Hermann J Heipieper
- Department of Environmental Biotechnology, Helmholtz Centre for Environmental Research - UFZ, Permoserstr. 15, 04318 Leipzig, Germany
| | - Michele M Bianchi
- Pasteur Institut Cenci-Bolognetti Foundation, Sapienza University of Rome, Italy.,Department of Biology and Biotechnology Charles Darwin, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy
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