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Gambacorta FV, Wagner ER, Jacobson TB, Tremaine M, Muehlbauer LK, McGee MA, Baerwald JJ, Wrobel RL, Wolters JF, Place M, Dietrich JJ, Xie D, Serate J, Gajbhiye S, Liu L, Vang-Smith M, Coon JJ, Zhang Y, Gasch AP, Amador-Noguez D, Hittinger CT, Sato TK, Pfleger BF. Comparative functional genomics identifies an iron-limited bottleneck in a Saccharomyces cerevisiae strain with a cytosolic-localized isobutanol pathway. Synth Syst Biotechnol 2022; 7:738-749. [PMID: 35387233 PMCID: PMC8938195 DOI: 10.1016/j.synbio.2022.02.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 12/17/2021] [Accepted: 02/14/2022] [Indexed: 11/20/2022] Open
Abstract
Metabolic engineering strategies have been successfully implemented to improve the production of isobutanol, a next-generation biofuel, in Saccharomyces cerevisiae. Here, we explore how two of these strategies, pathway re-localization and redox cofactor-balancing, affect the performance and physiology of isobutanol producing strains. We equipped yeast with isobutanol cassettes which had either a mitochondrial or cytosolic localized isobutanol pathway and used either a redox-imbalanced (NADPH-dependent) or redox-balanced (NADH-dependent) ketol-acid reductoisomerase enzyme. We then conducted transcriptomic, proteomic and metabolomic analyses to elucidate molecular differences between the engineered strains. Pathway localization had a large effect on isobutanol production with the strain expressing the mitochondrial-localized enzymes producing 3.8-fold more isobutanol than strains expressing the cytosolic enzymes. Cofactor-balancing did not improve isobutanol titers and instead the strain with the redox-imbalanced pathway produced 1.5-fold more isobutanol than the balanced version, albeit at low overall pathway flux. Functional genomic analyses suggested that the poor performances of the cytosolic pathway strains were in part due to a shortage in cytosolic Fe-S clusters, which are required cofactors for the dihydroxyacid dehydratase enzyme. We then demonstrated that this cofactor limitation may be partially recovered by disrupting iron homeostasis with a fra2 mutation, thereby increasing cellular iron levels. The resulting isobutanol titer of the fra2 null strain harboring a cytosolic-localized isobutanol pathway outperformed the strain with the mitochondrial-localized pathway by 1.3-fold, demonstrating that both localizations can support flux to isobutanol.
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Affiliation(s)
- Francesca V. Gambacorta
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, USA
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI, USA
| | - Ellen R. Wagner
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, USA
- Laboratory of Genetics, Center for Genomic Science Innovation, University of Wisconsin-Madison, Madison, WI, USA
| | - Tyler B. Jacobson
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, USA
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA
| | - Mary Tremaine
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, USA
| | | | - Mick A. McGee
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, USA
| | - Justin J. Baerwald
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI, USA
| | - Russell L. Wrobel
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, USA
- Laboratory of Genetics, Center for Genomic Science Innovation, University of Wisconsin-Madison, Madison, WI, USA
- Wisconsin Energy Institute, J. F. Crow Institute for the Study of Evolution, University of Wisconsin-Madison, Madison, WI, USA
| | - John F. Wolters
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, USA
- Laboratory of Genetics, Center for Genomic Science Innovation, University of Wisconsin-Madison, Madison, WI, USA
- Wisconsin Energy Institute, J. F. Crow Institute for the Study of Evolution, University of Wisconsin-Madison, Madison, WI, USA
| | - Mike Place
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, USA
| | - Joshua J. Dietrich
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, USA
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI, USA
| | - Dan Xie
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, USA
| | - Jose Serate
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, USA
| | - Shabda Gajbhiye
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, USA
| | - Lisa Liu
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, USA
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA
| | - Maikayeng Vang-Smith
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, USA
| | - Joshua J. Coon
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Yaoping Zhang
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, USA
| | - Audrey P. Gasch
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, USA
- Laboratory of Genetics, Center for Genomic Science Innovation, University of Wisconsin-Madison, Madison, WI, USA
| | - Daniel Amador-Noguez
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, USA
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA
| | - Chris Todd Hittinger
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, USA
- Laboratory of Genetics, Center for Genomic Science Innovation, University of Wisconsin-Madison, Madison, WI, USA
- Wisconsin Energy Institute, J. F. Crow Institute for the Study of Evolution, University of Wisconsin-Madison, Madison, WI, USA
| | - Trey K. Sato
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, USA
| | - Brian F. Pfleger
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, USA
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI, USA
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2
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Lee SB, Tremaine M, Place M, Liu L, Pier A, Krause DJ, Xie D, Zhang Y, Landick R, Gasch AP, Hittinger CT, Sato TK. Crabtree/Warburg-like aerobic xylose fermentation by engineered Saccharomyces cerevisiae. Metab Eng 2021; 68:119-130. [PMID: 34592433 DOI: 10.1016/j.ymben.2021.09.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 09/24/2021] [Accepted: 09/26/2021] [Indexed: 11/29/2022]
Abstract
Bottlenecks in the efficient conversion of xylose into cost-effective biofuels have limited the widespread use of plant lignocellulose as a renewable feedstock. The yeast Saccharomyces cerevisiae ferments glucose into ethanol with such high metabolic flux that it ferments high concentrations of glucose aerobically, a trait called the Crabtree/Warburg Effect. In contrast to glucose, most engineered S. cerevisiae strains do not ferment xylose at economically viable rates and yields, and they require respiration to achieve sufficient xylose metabolic flux and energy return for growth aerobically. Here, we evolved respiration-deficient S. cerevisiae strains that can grow on and ferment xylose to ethanol aerobically, a trait analogous to the Crabtree/Warburg Effect for glucose. Through genome sequence comparisons and directed engineering, we determined that duplications of genes encoding engineered xylose metabolism enzymes, as well as TKL1, a gene encoding a transketolase in the pentose phosphate pathway, were the causative genetic changes for the evolved phenotype. Reengineered duplications of these enzymes, in combination with deletion mutations in HOG1, ISU1, GRE3, and IRA2, increased the rates of aerobic and anaerobic xylose fermentation. Importantly, we found that these genetic modifications function in another genetic background and increase the rate and yield of xylose-to-ethanol conversion in industrially relevant switchgrass hydrolysate, indicating that these specific genetic modifications may enable the sustainable production of industrial biofuels from yeast. We propose a model for how key regulatory mutations prime yeast for aerobic xylose fermentation by lowering the threshold for overflow metabolism, allowing mutations to increase xylose flux and to redirect it into fermentation products.
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Affiliation(s)
- Sae-Byuk Lee
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, WI, USA; Wisconsin Energy Institute, J. F. Crow Institute for the Study of Evolution, University of Wisconsin-Madison, Madison, WI, USA; Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI, USA; Center for Genomic Science Innovation, University of Wisconsin-Madison, Madison, WI, USA
| | - Mary Tremaine
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, WI, USA
| | - Michael Place
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, WI, USA; Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI, USA; Center for Genomic Science Innovation, University of Wisconsin-Madison, Madison, WI, USA
| | - Lisa Liu
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, WI, USA
| | - Austin Pier
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, WI, USA
| | - David J Krause
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, WI, USA; Wisconsin Energy Institute, J. F. Crow Institute for the Study of Evolution, University of Wisconsin-Madison, Madison, WI, USA; Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI, USA; Center for Genomic Science Innovation, University of Wisconsin-Madison, Madison, WI, USA
| | - Dan Xie
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, WI, USA
| | - Yaoping Zhang
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, WI, USA
| | - Robert Landick
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, WI, USA; Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA; Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA
| | - Audrey P Gasch
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, WI, USA; Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI, USA; Center for Genomic Science Innovation, University of Wisconsin-Madison, Madison, WI, USA
| | - Chris Todd Hittinger
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, WI, USA; Wisconsin Energy Institute, J. F. Crow Institute for the Study of Evolution, University of Wisconsin-Madison, Madison, WI, USA; Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI, USA; Center for Genomic Science Innovation, University of Wisconsin-Madison, Madison, WI, USA.
| | - Trey K Sato
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, WI, USA.
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3
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Kim J, Tremaine M, Grass JA, Purdy HM, Landick R, Kiley PJ, Reed JL. Systems Metabolic Engineering of Escherichia coli Improves Coconversion of Lignocellulose-Derived Sugars. Biotechnol J 2019; 14:e1800441. [PMID: 31297978 DOI: 10.1002/biot.201800441] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 07/08/2019] [Indexed: 11/10/2022]
Abstract
Currently, microbial conversion of lignocellulose-derived glucose and xylose to biofuels is hindered by the fact that most microbes (including Escherichia coli [E. coli], Saccharomyces cerevisiae, and Zymomonas mobilis) preferentially consume glucose first and consume xylose slowly after glucose is depleted in lignocellulosic hydrolysates. In this study, E. coli strains are developed that simultaneously utilize glucose and xylose in lignocellulosic biomass hydrolysate using genome-scale models and adaptive laboratory evolution. E. coli strains are designed and constructed that coutilize glucose and xylose and adaptively evolve them to improve glucose and xylose utilization. Whole-genome resequencing of the evolved strains find relevant mutations in metabolic and regulatory genes and the mutations' involvement in sugar coutilization is investigated. The developed strains show significantly improved coconversion of sugars in lignocellulosic biomass hydrolysates and provide a promising platform for producing next-generation biofuels.
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Affiliation(s)
- Joonhoon Kim
- US Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, 53711, USA.,Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Dr, Madison, WI, 53711, USA
| | - Mary Tremaine
- US Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, 53711, USA
| | - Jeffrey A Grass
- US Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, 53711, USA
| | - Hugh M Purdy
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Dr, Madison, WI, 53711, USA
| | - Robert Landick
- US Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, 53711, USA.,Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, 53711, USA.,Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, 53711, USA
| | - Patricia J Kiley
- US Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, 53711, USA.,Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, 53711, USA
| | - Jennifer L Reed
- US Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, 53711, USA.,Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Dr, Madison, WI, 53711, USA
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4
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Higgins DA, Young MKM, Tremaine M, Sardi M, Fletcher JM, Agnew M, Liu L, Dickinson Q, Peris D, Wrobel RL, Hittinger CT, Gasch AP, Singer SW, Simmons BA, Landick R, Thelen MP, Sato TK. Natural Variation in the Multidrug Efflux Pump SGE1 Underlies Ionic Liquid Tolerance in Yeast. Genetics 2018; 210:219-234. [PMID: 30045857 PMCID: PMC6116967 DOI: 10.1534/genetics.118.301161] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 07/23/2018] [Indexed: 01/20/2023] Open
Abstract
Imidazolium ionic liquids (IILs) have a range of biotechnological applications, including as pretreatment solvents that extract cellulose from plant biomass for microbial fermentation into sustainable bioenergy. However, residual levels of IILs, such as 1-ethyl-3-methylimidazolium chloride ([C2C1im]Cl), are toxic to biofuel-producing microbes, including the yeast Saccharomyces cerevisiae. S. cerevisiae strains isolated from diverse ecological niches differ in genomic sequence and in phenotypes potentially beneficial for industrial applications, including tolerance to inhibitory compounds present in hydrolyzed plant feedstocks. We evaluated >100 genome-sequenced S. cerevisiae strains for tolerance to [C2C1im]Cl and identified one strain with exceptional tolerance. By screening a library of genomic DNA fragments from the [C2C1im]Cl-tolerant strain for improved IIL tolerance, we identified SGE1, which encodes a plasma membrane multidrug efflux pump, and a previously uncharacterized gene that we named ionic liquid tolerance 1 (ILT1), which encodes a predicted membrane protein. Analyses of SGE1 sequences from our panel of S. cerevisiae strains together with growth phenotypes implicated two single nucleotide polymorphisms (SNPs) that associated with IIL tolerance and sensitivity. We confirmed these phenotypic effects by transferring the SGE1 SNPs into a [C2C1im]Cl-sensitive yeast strain using CRISPR/Cas9 genome editing. Further studies indicated that these SNPs affect Sge1 protein stability and cell surface localization, influencing the amount of toxic IILs that cells can pump out of the cytoplasm. Our results highlight the general potential for discovering useful biotechnological functions from untapped natural sequence variation and provide functional insight into emergent SGE1 alleles with reduced capacities to protect against IIL toxicity.
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Affiliation(s)
- Douglas A Higgins
- Deconstruction Division, Joint BioEnergy Institute, Emeryville, California 94608
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, California 94550
| | - Megan K M Young
- Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Wisconsin 53726
| | - Mary Tremaine
- Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Wisconsin 53726
| | - Maria Sardi
- Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Wisconsin 53726
- Laboratory of Genetics, University of Wisconsin-Madison, Wisconsin 53726
| | - Jenna M Fletcher
- Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Wisconsin 53726
| | - Margaret Agnew
- Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Wisconsin 53726
| | - Lisa Liu
- Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Wisconsin 53726
| | - Quinn Dickinson
- Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Wisconsin 53726
| | - David Peris
- Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Wisconsin 53726
- Laboratory of Genetics, University of Wisconsin-Madison, Wisconsin 53726
| | - Russell L Wrobel
- Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Wisconsin 53726
- Laboratory of Genetics, University of Wisconsin-Madison, Wisconsin 53726
| | - Chris Todd Hittinger
- Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Wisconsin 53726
- Laboratory of Genetics, University of Wisconsin-Madison, Wisconsin 53726
| | - Audrey P Gasch
- Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Wisconsin 53726
- Laboratory of Genetics, University of Wisconsin-Madison, Wisconsin 53726
| | - Steven W Singer
- Deconstruction Division, Joint BioEnergy Institute, Emeryville, California 94608
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, California 94720
| | - Blake A Simmons
- Deconstruction Division, Joint BioEnergy Institute, Emeryville, California 94608
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, California 94550
| | - Robert Landick
- Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Wisconsin 53726
- Department of Biochemistry, University of Wisconsin-Madison, Wisconsin 53726
- Department of Bacteriology, University of Wisconsin-Madison, Wisconsin 53726
| | - Michael P Thelen
- Deconstruction Division, Joint BioEnergy Institute, Emeryville, California 94608
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, California 94550
| | - Trey K Sato
- Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Wisconsin 53726
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5
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Sato TK, Tremaine M, Parreiras LS, Hebert AS, Myers KS, Higbee AJ, Sardi M, McIlwain SJ, Ong IM, Breuer RJ, Narasimhan RA, McGee MA, Dickinson Q, La Reau A, Xie D, Tian M, Piotrowski JS, Reed JL, Zhang Y, Coon JJ, Hittinger CT, Gasch AP, Landick R. Correction: Directed Evolution Reveals Unexpected Epistatic Interactions That Alter Metabolic Regulation and Enable Anaerobic Xylose Use by Saccharomyces cerevisiae. PLoS Genet 2016; 12:e1006447. [PMID: 27828955 PMCID: PMC5102404 DOI: 10.1371/journal.pgen.1006447] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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6
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Sato TK, Tremaine M, Parreiras LS, Hebert AS, Myers KS, Higbee AJ, Sardi M, McIlwain SJ, Ong IM, Breuer RJ, Avanasi Narasimhan R, McGee MA, Dickinson Q, La Reau A, Xie D, Tian M, Reed JL, Zhang Y, Coon JJ, Hittinger CT, Gasch AP, Landick R. Directed Evolution Reveals Unexpected Epistatic Interactions That Alter Metabolic Regulation and Enable Anaerobic Xylose Use by Saccharomyces cerevisiae. PLoS Genet 2016; 12:e1006372. [PMID: 27741250 PMCID: PMC5065143 DOI: 10.1371/journal.pgen.1006372] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 09/19/2016] [Indexed: 11/25/2022] Open
Abstract
The inability of native Saccharomyces cerevisiae to convert xylose from plant biomass into biofuels remains a major challenge for the production of renewable bioenergy. Despite extensive knowledge of the regulatory networks controlling carbon metabolism in yeast, little is known about how to reprogram S. cerevisiae to ferment xylose at rates comparable to glucose. Here we combined genome sequencing, proteomic profiling, and metabolomic analyses to identify and characterize the responsible mutations in a series of evolved strains capable of metabolizing xylose aerobically or anaerobically. We report that rapid xylose conversion by engineered and evolved S. cerevisiae strains depends upon epistatic interactions among genes encoding a xylose reductase (GRE3), a component of MAP Kinase (MAPK) signaling (HOG1), a regulator of Protein Kinase A (PKA) signaling (IRA2), and a scaffolding protein for mitochondrial iron-sulfur (Fe-S) cluster biogenesis (ISU1). Interestingly, the mutation in IRA2 only impacted anaerobic xylose consumption and required the loss of ISU1 function, indicating a previously unknown connection between PKA signaling, Fe-S cluster biogenesis, and anaerobiosis. Proteomic and metabolomic comparisons revealed that the xylose-metabolizing mutant strains exhibit altered metabolic pathways relative to the parental strain when grown in xylose. Further analyses revealed that interacting mutations in HOG1 and ISU1 unexpectedly elevated mitochondrial respiratory proteins and enabled rapid aerobic respiration of xylose and other non-fermentable carbon substrates. Our findings suggest a surprising connection between Fe-S cluster biogenesis and signaling that facilitates aerobic respiration and anaerobic fermentation of xylose, underscoring how much remains unknown about the eukaryotic signaling systems that regulate carbon metabolism. The yeast Saccharomyces cerevisiae is being genetically engineered to produce renewable biofuels from sustainable plant material. Efficient biofuel production from plant material requires conversion of the complex suite of sugars found in plant material, including the five-carbon sugar xylose. Because it does not efficiently metabolize xylose, S. cerevisiae has been engineered with a minimal set of genes that should overcome this problem; however, additional genetic changes are required for optimal fermentative conversion of xylose into biofuel. Despite extensive knowledge of the regulatory networks controlling glucose metabolism, less is known about the regulation of xylose metabolism and how to rewire these networks for effective biofuel production. Here we report genetic mutations that enabled the conversion of xylose into bioethanol by a previously ineffective yeast strain. By comparing altered protein and metabolite abundance within yeast cells containing these mutations, we determined that the mutations synergistically alter metabolic pathways to improve the rate of xylose conversion. One change in a gene with well-characterized aerobic mitochondrial functions was found to play an unexpected role in anaerobic conversion of xylose into ethanol. The results of this work will allow others to rapidly generate yeast strains for the conversion of xylose into biofuels and other products.
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Affiliation(s)
- Trey K. Sato
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- * E-mail: (TKS); (APG); (RL)
| | - Mary Tremaine
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Lucas S. Parreiras
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Alexander S. Hebert
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Genome Center of Wisconsin, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Kevin S. Myers
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Genome Center of Wisconsin, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Alan J. Higbee
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Genome Center of Wisconsin, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Maria Sardi
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Genome Center of Wisconsin, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Sean J. McIlwain
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Irene M. Ong
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Rebecca J. Breuer
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Ragothaman Avanasi Narasimhan
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Mick A. McGee
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Quinn Dickinson
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Alex La Reau
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Dan Xie
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Mingyuan Tian
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Jennifer L. Reed
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Yaoping Zhang
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Joshua J. Coon
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Genome Center of Wisconsin, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Chris Todd Hittinger
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Genome Center of Wisconsin, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Wisconsin Energy Institute, J.F. Crow Institute for the Study of Evolution, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Audrey P. Gasch
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Genome Center of Wisconsin, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- * E-mail: (TKS); (APG); (RL)
| | - Robert Landick
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- * E-mail: (TKS); (APG); (RL)
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7
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Keating DH, Zhang Y, Ong IM, McIlwain S, Morales EH, Grass JA, Tremaine M, Bothfeld W, Higbee A, Ulbrich A, Balloon AJ, Westphall MS, Aldrich J, Lipton MS, Kim J, Moskvin OV, Bukhman YV, Coon JJ, Kiley PJ, Bates DM, Landick R. Aromatic inhibitors derived from ammonia-pretreated lignocellulose hinder bacterial ethanologenesis by activating regulatory circuits controlling inhibitor efflux and detoxification. Front Microbiol 2014; 5:402. [PMID: 25177315 PMCID: PMC4132294 DOI: 10.3389/fmicb.2014.00402] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Accepted: 07/17/2014] [Indexed: 11/13/2022] Open
Abstract
Efficient microbial conversion of lignocellulosic hydrolysates to biofuels is a key barrier to the economically viable deployment of lignocellulosic biofuels. A chief contributor to this barrier is the impact on microbial processes and energy metabolism of lignocellulose-derived inhibitors, including phenolic carboxylates, phenolic amides (for ammonia-pretreated biomass), phenolic aldehydes, and furfurals. To understand the bacterial pathways induced by inhibitors present in ammonia-pretreated biomass hydrolysates, which are less well studied than acid-pretreated biomass hydrolysates, we developed and exploited synthetic mimics of ammonia-pretreated corn stover hydrolysate (ACSH). To determine regulatory responses to the inhibitors normally present in ACSH, we measured transcript and protein levels in an Escherichia coli ethanologen using RNA-seq and quantitative proteomics during fermentation to ethanol of synthetic hydrolysates containing or lacking the inhibitors. Our study identified four major regulators mediating these responses, the MarA/SoxS/Rob network, AaeR, FrmR, and YqhC. Induction of these regulons was correlated with a reduced rate of ethanol production, buildup of pyruvate, depletion of ATP and NAD(P)H, and an inhibition of xylose conversion. The aromatic aldehyde inhibitor 5-hydroxymethylfurfural appeared to be reduced to its alcohol form by the ethanologen during fermentation, whereas phenolic acid and amide inhibitors were not metabolized. Together, our findings establish that the major regulatory responses to lignocellulose-derived inhibitors are mediated by transcriptional rather than translational regulators, suggest that energy consumed for inhibitor efflux and detoxification may limit biofuel production, and identify a network of regulators for future synthetic biology efforts.
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Affiliation(s)
- David H Keating
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison Madison, WI, USA
| | - Yaoping Zhang
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison Madison, WI, USA
| | - Irene M Ong
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison Madison, WI, USA
| | - Sean McIlwain
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison Madison, WI, USA
| | - Eduardo H Morales
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison Madison, WI, USA ; Department of Biomolecular Chemistry, University of Wisconsin-Madison Madison, WI, USA
| | - Jeffrey A Grass
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison Madison, WI, USA ; Department of Biochemistry, University of Wisconsin-Madison Madison, WI, USA
| | - Mary Tremaine
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison Madison, WI, USA
| | - William Bothfeld
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison Madison, WI, USA
| | - Alan Higbee
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison Madison, WI, USA
| | - Arne Ulbrich
- Department of Chemistry, University of Wisconsin-Madison Madison, WI, USA
| | - Allison J Balloon
- Department of Chemistry, University of Wisconsin-Madison Madison, WI, USA
| | - Michael S Westphall
- Department of Biomolecular Chemistry, University of Wisconsin-Madison Madison, WI, USA ; Department of Chemistry, University of Wisconsin-Madison Madison, WI, USA
| | - Josh Aldrich
- Pacific Northwest National Laboratory Richland, WA, USA
| | - Mary S Lipton
- Pacific Northwest National Laboratory Richland, WA, USA
| | - Joonhoon Kim
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison Madison, WI, USA ; Department of Chemical and Biological Engineering, University of Wisconsin-Madison Madison, WI, USA
| | - Oleg V Moskvin
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison Madison, WI, USA
| | - Yury V Bukhman
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison Madison, WI, USA
| | - Joshua J Coon
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison Madison, WI, USA ; Department of Biomolecular Chemistry, University of Wisconsin-Madison Madison, WI, USA ; Department of Chemistry, University of Wisconsin-Madison Madison, WI, USA
| | - Patricia J Kiley
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison Madison, WI, USA ; Department of Biomolecular Chemistry, University of Wisconsin-Madison Madison, WI, USA
| | - Donna M Bates
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison Madison, WI, USA
| | - Robert Landick
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison Madison, WI, USA ; Department of Biochemistry, University of Wisconsin-Madison Madison, WI, USA ; Department of Bacteriology, University of Wisconsin-Madison Madison, WI, USA
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Adamovich SV, Merians AS, Boian R, Tremaine M, Burdea GS, Recce M, Poizner H. A virtual reality based exercise system for hand rehabilitation post-stroke: transfer to function. Conf Proc IEEE Eng Med Biol Soc 2007; 2004:4936-9. [PMID: 17271420 DOI: 10.1109/iembs.2004.1404364] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We present preliminary results from a virtual reality (VR)-based system for hand rehabilitation that uses a CyberGlove and a Rutgers Master II-ND haptic glove. This system trains finger range of motion, finger flexion speed, independence of finger motion and finger strength. Eight chronic post-stroke subjects participated. In keeping with variability in both the lesion site and in initial upper extremity function, each subject showed improvement on a unique combination of movement parameters in VR training. These improvements transferred to gains on clinical tests, as well as to significant reductions in task completion times for the prehension of real objects. These results are indicative of the potential feasibility of this exercise system for rehabilitation in patients with hand dysfunction resulting from neurological impairment.
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Affiliation(s)
- S V Adamovich
- Department of Biomedical Engineering, New Jersey Institute of Technology, Newark, NJ, USA
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Boian R, Sharma A, Han C, Merians A, Burdea G, Adamovich S, Recce M, Tremaine M, Poizner H. Virtual reality-based post-stroke hand rehabilitation. Stud Health Technol Inform 2002; 85:64-70. [PMID: 15458061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/30/2023]
Abstract
A VR-based system using a CyberGlove and a Rutgers Master II-ND haptic glove was used to rehabilitate four post-stroke patients in the chronic phase. Each patient had to perform a variety of VR exercises to reduce impairments in their finger range of motion, speed, fractionation and strength. Patients exercised for about two hours per day, five days a week for three weeks. Results showed that three of the patients had gains in thumb range (50-140%) and finger speed (10-15%) over the three weeks trial. All four patients had significant improvement in finger fractionation (40-118%). Gains in finger strength were modest, due in part to an unexpected hardware malfunction. Two of the patients were measured against one-month post intervention and showed good retention. Evaluation using the Jebsen Test of Hand Function showed a reduction of 23-28% in time completion for two of the patients (the ones with the higher degrees of impairment). A prehension task was performed 9-40% faster for three of the patients after the intervention illustrating transfer of their improvement to a functional task.
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Affiliation(s)
- R Boian
- Center for Advanced Information Processing, Rutgers University, Piscataway, NJ, USA
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10
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Jack D, Boian R, Merians AS, Tremaine M, Burdea GC, Adamovich SV, Recce M, Poizner H. Virtual reality-enhanced stroke rehabilitation. IEEE Trans Neural Syst Rehabil Eng 2001; 9:308-18. [PMID: 11561668 DOI: 10.1109/7333.948460] [Citation(s) in RCA: 486] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A personal computer (PC)-based desktop virtual reality (VR) system was developed for rehabilitating hand function in stroke patients. The system uses two input devices, a CyberGlove and a Rutgers Master II-ND (RMII) force feedback glove, allowing user interaction with a virtual environment. This consists of four rehabilitation routines, each designed to exercise one specific parameter of hand movement: range, speed, fractionation or strength. The use of performance-based target levels is designed to increase patient motivation and individualize exercise difficulty to a patient's current state. Pilot clinical trials have been performed using the above system combined with noncomputer tasks, such as pegboard insertion or tracing of two-dimensional (2-D) patterns. Three chronic stroke patients used this rehabilitation protocol daily for two weeks. Objective measurements showed that each patient showed improvement on most of the hand parameters over the course of the training. Subjective evaluation by the patients was also positive. This technical report focuses on this newly developed technology for VR rehabilitation.
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Affiliation(s)
- D Jack
- Center for Molecular and Behavioral Neuroscience, Rutgers University, Newark, NJ 07102, USA
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Abstract
The goal of this study was to examine the role of histidine residues in the biological activities of staphylococcal enterotoxin A (SEA). Carboxymethylated SEA was unable to stimulate murine T-cell proliferation but was resistant to monkey stomach lavage fluid degradation, suggesting that native conformation was intact. Site-directed mutagenesis of the histidine residues of SEA was subsequently performed. SEA-H44A (SEA with histidine 44 replaced with alanine), SEA-H44D, SEA-H50A, SEA-H50D, SEA-H114A, SEA-H114D, SEA-H187A, and SEA-H187D retained superantigen and emetic activities, whereas SEA-H225A and SEA-H225D were defective in the ability to stimulate T-cell proliferation. These mutants were unable to compete with SEA for binding to Raji cells, suggesting that the defect in SEA-H225A and SEA-H225D is due to impaired major histocompatibility complex class II binding. SEA-H225D provoked an emetic response in monkeys only if fed at high doses, while SEA-H225A did not provoke an emetic response at low or high doses. In comparison, SEA-H61A and SEA-H61D were defective in emetic activity but not in the ability to stimulate murine T-cell proliferation. Overall, these studies show that the carboxy-terminal histidine at residue position 225 of SEA is important for both the superantigen and emetic activities of this enterotoxin. Histidine 61 appears to be important for emetic activity but not for superantigen activity, consistent with the hypothesis that the two activities are separable in staphylococcal enterotoxins.
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Affiliation(s)
- M Hoffman
- Department of Bacteriology, University of Wisconsin - Madison, 53706, USA
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Putland RA, Ford J, Korban G, Evdokiou A, Tremaine M. Investigation of spontaneously aborted concepti for microbial DNA: investigation for cytomegalovirus DNA using polymerase chain reaction. Aust N Z J Obstet Gynaecol 1990; 30:248-50. [PMID: 2175172 DOI: 10.1111/j.1479-828x.1990.tb03225.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Karyotypic analysis of concepti spontaneously aborted in the first trimester shows approximately 50% of these concepti contain abnormal chromosomes. In order to determine whether cytomegalovirus (CMV) infection may play a role in the early loss of pregnancies with either normal or abnormal chromosomes, we have developed an assay to amplify CMV DNA in DNA extracts from spontaneously aborted concepti using the polymerase chain reaction (PCR). Using PCR, we were unable to detect CMV DNA in any of 350 spontaneously aborted concepti. Viral cultures were also negative when 36 of these were tested. Our results suggest that CMV infection is an unlikely cause of pregnancy loss in the first trimester of pregnancy.
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Affiliation(s)
- R A Putland
- Clinical Microbiology Department, Queen Elizabeth Hospital, Woodville, South Australia
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