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Kim LJ, Chalmers TJ, Madawala R, Smith GC, Li C, Das A, Poon EWK, Wang J, Tucker SP, Sinclair DA, Quek LE, Wu LE. Host-microbiome interactions in nicotinamide mononucleotide (NMN) deamidation. FEBS Lett 2023; 597:2196-2220. [PMID: 37463842 DOI: 10.1002/1873-3468.14698] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 06/04/2023] [Accepted: 06/13/2023] [Indexed: 07/20/2023]
Abstract
The nicotinamide adenine dinucleotide (NAD+ ) precursor nicotinamide mononucleotide (NMN) is a proposed therapy for age-related disease, whereby it is assumed that NMN is incorporated into NAD+ through the canonical recycling pathway. During oral delivery, NMN is exposed to the gut microbiome, which could modify the NAD+ metabolome through enzyme activities not present in the mammalian host. We show that orally delivered NMN can undergo deamidation and incorporation in mammalian tissue via the de novo pathway, which is reduced in animals treated with antibiotics to ablate the gut microbiome. Antibiotics increased the availability of NAD+ metabolites, suggesting the microbiome could be in competition with the host for dietary NAD+ precursors. These findings highlight new interactions between NMN and the gut microbiome.
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Affiliation(s)
- Lynn-Jee Kim
- School of Biomedical Sciences, UNSW Sydney, NSW, Australia
| | | | | | - Greg C Smith
- School of Biomedical Sciences, UNSW Sydney, NSW, Australia
| | - Catherine Li
- School of Biomedical Sciences, UNSW Sydney, NSW, Australia
| | - Abhirup Das
- School of Biomedical Sciences, UNSW Sydney, NSW, Australia
| | | | - Jun Wang
- GeneHarbor (Hong Kong) Biotechnologies Limited, Hong Kong Science Park, China
- School of Life Sciences, The Chinese University of Hong Kong, China
| | | | - David A Sinclair
- School of Biomedical Sciences, UNSW Sydney, NSW, Australia
- Harvard Medical School, Boston, MA, USA
| | - Lake-Ee Quek
- School of Mathematics and Statistics, The University of Sydney, NSW, Australia
| | - Lindsay E Wu
- School of Biomedical Sciences, UNSW Sydney, NSW, Australia
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2
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Moxley WC, Brown RE, Eiteman MA. Escherichia coli aceE variants coding pyruvate dehydrogenase improve the generation of pyruvate-derived acetoin. Eng Life Sci 2023; 23:e2200054. [PMID: 36874610 PMCID: PMC9978916 DOI: 10.1002/elsc.202200054] [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: 09/23/2022] [Revised: 11/23/2022] [Accepted: 01/07/2023] [Indexed: 02/04/2023] Open
Abstract
Several chromosomally expressed AceE variants were constructed in Escherichia coli ΔldhA ΔpoxB ΔppsA and compared using glucose as the sole carbon source. These variants were examined in shake flask cultures for growth rate, pyruvate accumulation, and acetoin production via heterologous expression of the budA and budB genes from Enterobacter cloacae ssp. dissolvens. The best acetoin-producing strains were subsequently studied in controlled batch culture at the one-liter scale. PDH variant strains attained up to four-fold greater acetoin than the strain expressing the wild-type PDH. In a repeated batch process, the H106V PDH variant strain attained over 43 g/L of pyruvate-derived products, acetoin (38.5 g/L) and 2R,3R-butanediol (5.0 g/L), corresponding to an effective concentration of 59 g/L considering the dilution. The acetoin yield from glucose was 0.29 g/g with a volumetric productivity of 0.9 g/L·h (0.34 g/g and 1.0 g/L·h total products). The results demonstrate a new tool in pathway engineering, the modification of a key metabolic enzyme to improve the formation of a product via a kinetically slow, introduced pathway. Direct modification of the pathway enzyme offers an alternative to promoter engineering in cases where the promoter is involved in a complex regulatory network.
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Affiliation(s)
- W. Chris Moxley
- Department of MicrobiologyUniversity of GeorgiaAthensGeorgiaUSA
| | - Rachel E. Brown
- School of ChemicalMaterials and Biomedical EngineeringUniversity of GeorgiaAthensGeorgiaUSA
| | - Mark A. Eiteman
- Department of MicrobiologyUniversity of GeorgiaAthensGeorgiaUSA
- School of ChemicalMaterials and Biomedical EngineeringUniversity of GeorgiaAthensGeorgiaUSA
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3
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Sauvaitre T, Van Landuyt J, Durif C, Roussel C, Sivignon A, Chalancon S, Uriot O, Van Herreweghen F, Van de Wiele T, Etienne-Mesmin L, Blanquet-Diot S. Role of mucus-bacteria interactions in Enterotoxigenic Escherichia coli (ETEC) H10407 virulence and interplay with human microbiome. NPJ Biofilms Microbiomes 2022; 8:86. [PMID: 36266277 PMCID: PMC9584927 DOI: 10.1038/s41522-022-00344-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 10/04/2022] [Indexed: 11/09/2022] Open
Abstract
The intestinal mucus layer has a dual role in human health constituting a well-known microbial niche that supports gut microbiota maintenance but also acting as a physical barrier against enteric pathogens. Enterotoxigenic Escherichia coli (ETEC), the major agent responsible for traveler's diarrhea, is able to bind and degrade intestinal mucins, representing an important but understudied virulent trait of the pathogen. Using a set of complementary in vitro approaches simulating the human digestive environment, this study aimed to describe how the mucus microenvironment could shape different aspects of the human ETEC strain H10407 pathophysiology, namely its survival, adhesion, virulence gene expression, interleukin-8 induction and interactions with human fecal microbiota. Using the TNO gastrointestinal model (TIM-1) simulating the physicochemical conditions of the human upper gastrointestinal (GI) tract, we reported that mucus secretion and physical surface sustained ETEC survival, probably by helping it to face GI stresses. When integrating the host part in Caco2/HT29-MTX co-culture model, we demonstrated that mucus secreting-cells favored ETEC adhesion and virulence gene expression, but did not impede ETEC Interleukin-8 (IL-8) induction. Furthermore, we proved that mucosal surface did not favor ETEC colonization in a complex gut microbial background simulated in batch fecal experiments. However, the mucus-specific microbiota was widely modified upon the ETEC challenge suggesting its role in the pathogen infectious cycle. Using multi-targeted in vitro approaches, this study supports the major role played by mucus in ETEC pathophysiology, opening avenues in the design of new treatment strategies.
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Affiliation(s)
- Thomas Sauvaitre
- Université Clermont Auvergne, INRAE, UMR 454 MEDIS, Microbiologie Environnement Digestif et Santé (MEDIS), CRNH Auvergne, 63000, Clermont-Ferrand, France.,Ghent University, Faculty of Bioscience Engineering, Center for Microbial Ecology and Technology (CMET), Ghent, Belgium
| | - Josefien Van Landuyt
- Ghent University, Faculty of Bioscience Engineering, Center for Microbial Ecology and Technology (CMET), Ghent, Belgium
| | - Claude Durif
- Université Clermont Auvergne, INRAE, UMR 454 MEDIS, Microbiologie Environnement Digestif et Santé (MEDIS), CRNH Auvergne, 63000, Clermont-Ferrand, France
| | - Charlène Roussel
- Université Laval, Nutrition and Functional Foods Institute (INAF), 2440 Bd Hochelaga Suite 1710, Québec, QC, G1V 0A6, Canada
| | - Adeline Sivignon
- Université Clermont Auvergne, UMR 1071 Inserm, USC-INRAE 2018, Microbes, Intestin, Inflammation et Susceptibilité de l'Hôte (M2iSH), 63000, Clermont-Ferrand, France
| | - Sandrine Chalancon
- Université Clermont Auvergne, INRAE, UMR 454 MEDIS, Microbiologie Environnement Digestif et Santé (MEDIS), CRNH Auvergne, 63000, Clermont-Ferrand, France
| | - Ophélie Uriot
- Université Clermont Auvergne, INRAE, UMR 454 MEDIS, Microbiologie Environnement Digestif et Santé (MEDIS), CRNH Auvergne, 63000, Clermont-Ferrand, France
| | - Florence Van Herreweghen
- Ghent University, Faculty of Bioscience Engineering, Center for Microbial Ecology and Technology (CMET), Ghent, Belgium
| | - Tom Van de Wiele
- Ghent University, Faculty of Bioscience Engineering, Center for Microbial Ecology and Technology (CMET), Ghent, Belgium
| | - Lucie Etienne-Mesmin
- Université Clermont Auvergne, INRAE, UMR 454 MEDIS, Microbiologie Environnement Digestif et Santé (MEDIS), CRNH Auvergne, 63000, Clermont-Ferrand, France
| | - Stéphanie Blanquet-Diot
- Université Clermont Auvergne, INRAE, UMR 454 MEDIS, Microbiologie Environnement Digestif et Santé (MEDIS), CRNH Auvergne, 63000, Clermont-Ferrand, France.
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4
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Sauvaitre T, Van Herreweghen F, Delbaere K, Durif C, Van Landuyt J, Fadhlaoui K, Huille S, Chaucheyras-Durand F, Etienne-Mesmin L, Blanquet-Diot S, Van de Wiele T. Lentils and Yeast Fibers: A New Strategy to Mitigate Enterotoxigenic Escherichia coli (ETEC) Strain H10407 Virulence? Nutrients 2022; 14:nu14102146. [PMID: 35631287 PMCID: PMC9144138 DOI: 10.3390/nu14102146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 05/16/2022] [Accepted: 05/18/2022] [Indexed: 01/10/2023] Open
Abstract
Dietary fibers exhibit well-known beneficial effects on human health, but their anti-infectious properties against enteric pathogens have been poorly investigated. Enterotoxigenic Escherichia coli (ETEC) is a major food-borne pathogen that causes acute traveler’s diarrhea. Its virulence traits mainly rely on adhesion to an epithelial surface, mucus degradation, and the secretion of two enterotoxins associated with intestinal inflammation. With the increasing burden of antibiotic resistance worldwide, there is an imperious need to develop novel alternative strategies to control ETEC infections. This study aimed to investigate, using complementary in vitro approaches, the inhibitory potential of two dietary-fiber-containing products (a lentil extract and yeast cell walls) against the human ETEC reference strain H10407. We showed that the lentil extract decreased toxin production in a dose-dependent manner, reduced pro-inflammatory interleukin-8 production, and modulated mucus-related gene induction in ETEC-infected mucus-secreting intestinal cells. We also report that the yeast product reduced ETEC adhesion to mucin and Caco-2/HT29-MTX cells. Both fiber-containing products strengthened intestinal barrier function and modulated toxin-related gene expression. In a complex human gut microbial background, both products did not elicit a significant effect on ETEC colonization. These pioneering data demonstrate the promising role of dietary fibers in controlling different stages of the ETEC infection process.
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Affiliation(s)
- Thomas Sauvaitre
- UMR 454 INRAE, Microbiology, Digestive Environment and Health (MEDIS), Université Clermont Auvergne, 28 Place Henri Dunant, F-63000 Clermont-Ferrand, France; (T.S.); (C.D.); (K.F.); (F.C.-D.); (L.E.-M.)
- Center for Microbial Ecology and Technology (CMET), Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium; (F.V.H.); (K.D.); (J.V.L.); (T.V.d.W.)
| | - Florence Van Herreweghen
- Center for Microbial Ecology and Technology (CMET), Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium; (F.V.H.); (K.D.); (J.V.L.); (T.V.d.W.)
| | - Karen Delbaere
- Center for Microbial Ecology and Technology (CMET), Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium; (F.V.H.); (K.D.); (J.V.L.); (T.V.d.W.)
| | - Claude Durif
- UMR 454 INRAE, Microbiology, Digestive Environment and Health (MEDIS), Université Clermont Auvergne, 28 Place Henri Dunant, F-63000 Clermont-Ferrand, France; (T.S.); (C.D.); (K.F.); (F.C.-D.); (L.E.-M.)
| | - Josefien Van Landuyt
- Center for Microbial Ecology and Technology (CMET), Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium; (F.V.H.); (K.D.); (J.V.L.); (T.V.d.W.)
| | - Khaled Fadhlaoui
- UMR 454 INRAE, Microbiology, Digestive Environment and Health (MEDIS), Université Clermont Auvergne, 28 Place Henri Dunant, F-63000 Clermont-Ferrand, France; (T.S.); (C.D.); (K.F.); (F.C.-D.); (L.E.-M.)
| | | | - Frédérique Chaucheyras-Durand
- UMR 454 INRAE, Microbiology, Digestive Environment and Health (MEDIS), Université Clermont Auvergne, 28 Place Henri Dunant, F-63000 Clermont-Ferrand, France; (T.S.); (C.D.); (K.F.); (F.C.-D.); (L.E.-M.)
- Lallemand SAS, 19 Rue des Briquetiers, BP 59, CEDEX, F-31702 Blagnac, France
| | - Lucie Etienne-Mesmin
- UMR 454 INRAE, Microbiology, Digestive Environment and Health (MEDIS), Université Clermont Auvergne, 28 Place Henri Dunant, F-63000 Clermont-Ferrand, France; (T.S.); (C.D.); (K.F.); (F.C.-D.); (L.E.-M.)
| | - Stéphanie Blanquet-Diot
- UMR 454 INRAE, Microbiology, Digestive Environment and Health (MEDIS), Université Clermont Auvergne, 28 Place Henri Dunant, F-63000 Clermont-Ferrand, France; (T.S.); (C.D.); (K.F.); (F.C.-D.); (L.E.-M.)
- Correspondence: ; Tel.: +33-(0)4-73-17-83-90
| | - Tom Van de Wiele
- Center for Microbial Ecology and Technology (CMET), Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium; (F.V.H.); (K.D.); (J.V.L.); (T.V.d.W.)
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5
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Baptista ISC, Kandavalli V, Chauhan V, Bahrudeen MNM, Almeida BLB, Palma CSD, Dash S, Ribeiro AS. Sequence-dependent model of genes with dual σ factor preference. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2022; 1865:194812. [PMID: 35338024 DOI: 10.1016/j.bbagrm.2022.194812] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 03/08/2022] [Accepted: 03/16/2022] [Indexed: 10/18/2022]
Abstract
Escherichia coli uses σ factors to quickly control large gene cohorts during stress conditions. While most of its genes respond to a single σ factor, approximately 5% of them have dual σ factor preference. The most common are those responsive to both σ70, which controls housekeeping genes, and σ38, which activates genes during stationary growth and stresses. Using RNA-seq and flow-cytometry measurements, we show that 'σ70+38 genes' are nearly as upregulated in stationary growth as 'σ38 genes'. Moreover, we find a clear quantitative relationship between their promoter sequence and their response strength to changes in σ38 levels. We then propose and validate a sequence dependent model of σ70+38 genes, with dual sensitivity to σ38 and σ70, that is applicable in the exponential and stationary growth phases, as well in the transient period in between. We further propose a general model, applicable to other stresses and σ factor combinations. Given this, promoters controlling σ70+38 genes (and variants) could become important building blocks of synthetic circuits with predictable, sequence-dependent sensitivity to transitions between the exponential and stationary growth phases.
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Affiliation(s)
- Ines S C Baptista
- Laboratory of Biosystem Dynamics, Faculty of Medicine and Health Technology, Tampere University, Tampere 33520, Finland
| | - Vinodh Kandavalli
- Laboratory of Biosystem Dynamics, Faculty of Medicine and Health Technology, Tampere University, Tampere 33520, Finland; Department of Cell and Molecular Biology, Uppsala University, Uppsala 752 37, Sweden
| | - Vatsala Chauhan
- Laboratory of Biosystem Dynamics, Faculty of Medicine and Health Technology, Tampere University, Tampere 33520, Finland
| | - Mohamed N M Bahrudeen
- Laboratory of Biosystem Dynamics, Faculty of Medicine and Health Technology, Tampere University, Tampere 33520, Finland
| | - Bilena L B Almeida
- Laboratory of Biosystem Dynamics, Faculty of Medicine and Health Technology, Tampere University, Tampere 33520, Finland
| | - Cristina S D Palma
- Laboratory of Biosystem Dynamics, Faculty of Medicine and Health Technology, Tampere University, Tampere 33520, Finland
| | - Suchintak Dash
- Laboratory of Biosystem Dynamics, Faculty of Medicine and Health Technology, Tampere University, Tampere 33520, Finland
| | - Andre S Ribeiro
- Laboratory of Biosystem Dynamics, Faculty of Medicine and Health Technology, Tampere University, Tampere 33520, Finland; Center of Technology and Systems (CTS-Uninova), NOVA University of Lisbon, 2829-516 Monte de Caparica, Portugal.
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6
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Gresse R, Chaucheyras-Durand F, Garrido JJ, Denis S, Jiménez-Marín A, Beaumont M, Van de Wiele T, Forano E, Blanquet-Diot S. Pathogen Challenge and Dietary Shift Alter Microbiota Composition and Activity in a Mucin-Associated in vitro Model of the Piglet Colon (MPigut-IVM) Simulating Weaning Transition. Front Microbiol 2021; 12:703421. [PMID: 34349744 PMCID: PMC8328230 DOI: 10.3389/fmicb.2021.703421] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 06/24/2021] [Indexed: 12/13/2022] Open
Abstract
Enterotoxigenic Escherichia coli (ETEC) is the principal pathogen responsible for post-weaning diarrhea in newly weaned piglets. Expansion of ETEC at weaning is thought to be the consequence of various stress factors such as transient anorexia, dietary change or increase in intestinal inflammation and permeability, but the exact mechanisms remain to be elucidated. As the use of animal experiments raise more and more ethical concerns, we used a recently developed in vitro model of piglet colonic microbiome and mucobiome, the MPigut-IVM, to evaluate the effects of a simulated weaning transition and pathogen challenge at weaning. Our data suggested that the tested factors impacted the composition and functionality of the MPigut-IVM microbiota. The simulation of weaning transition led to an increase in relative abundance of the Prevotellaceae family which was further promoted by the presence of the ETEC strain. In contrast, several beneficial families such as Bacteroidiaceae or Ruminococcaceae and gut health related short chain fatty acids like butyrate or acetate were reduced upon simulated weaning. Moreover, the incubation of MPigut-IVM filtrated effluents with porcine intestinal cell cultures showed that ETEC challenge in the in vitro model led to an increased expression of pro-inflammatory genes by the porcine cells. This study provides insights about the etiology of a dysbiotic microbiota in post-weaning piglets.
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Affiliation(s)
- Raphaële Gresse
- INRAE, UMR 454 MEDIS, Université Clermont Auvergne, Clermont-Ferrand, France.,Lallemand SAS, Blagnac, France
| | | | - Juan J Garrido
- Grupo de Genómica y Mejora Animal, Departamento de Genética, Facultad de Veterinaria, Universidad de Córdoba, Córdoba, Spain
| | - Sylvain Denis
- INRAE, UMR 454 MEDIS, Université Clermont Auvergne, Clermont-Ferrand, France
| | - Angeles Jiménez-Marín
- Grupo de Genómica y Mejora Animal, Departamento de Genética, Facultad de Veterinaria, Universidad de Córdoba, Córdoba, Spain
| | - Martin Beaumont
- GenPhySE, INRAE, ENVT, Université de Toulouse, Castanet-Tolosan, France
| | - Tom Van de Wiele
- Center for Microbial Ecology and Technology, Ghent University, Ghent, Belgium
| | - Evelyne Forano
- INRAE, UMR 454 MEDIS, Université Clermont Auvergne, Clermont-Ferrand, France
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7
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Moxley WC, Eiteman MA. Pyruvate Production by Escherichia coli by Use of Pyruvate Dehydrogenase Variants. Appl Environ Microbiol 2021; 87:e0048721. [PMID: 33863707 PMCID: PMC8315933 DOI: 10.1128/aem.00487-21] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 04/10/2021] [Indexed: 11/20/2022] Open
Abstract
Altering metabolic flux at a key branch point in metabolism has commonly been accomplished through gene knockouts or by modulating gene expression. An alternative approach to direct metabolic flux preferentially toward a product is decreasing the activity of a key enzyme through protein engineering. In Escherichia coli, pyruvate can accumulate from glucose when carbon flux through the pyruvate dehydrogenase complex is suppressed. Based on this principle, 16 chromosomally expressed AceE variants were constructed in E. coli C and compared for growth rate and pyruvate accumulation using glucose as the sole carbon source. To prevent conversion of pyruvate to other products, the strains also contained deletions in two nonessential pathways: lactate dehydrogenase (ldhA) and pyruvate oxidase (poxB). The effect of deleting phosphoenolpyruvate synthase (ppsA) on pyruvate assimilation was also examined. The best pyruvate-accumulating strains were examined in controlled batch and continuous processes. In a nitrogen-limited chemostat process at steady-state growth rates of 0.15 to 0.28 h-1, an engineered strain expressing the AceE[H106V] variant accumulated pyruvate at a yield of 0.59 to 0.66 g pyruvate/g glucose with a specific productivity of 0.78 to 0.92 g pyruvate/g cells·h. These results provide proof of concept that pyruvate dehydrogenase complex variants can effectively shift carbon flux away from central carbon metabolism to allow pyruvate accumulation. This approach can potentially be applied to other key enzymes in metabolism to direct carbon toward a biochemical product. IMPORTANCE Microbial production of biochemicals from renewable resources has become an efficient and cost-effective alternative to traditional chemical synthesis methods. Metabolic engineering tools are important for optimizing a process to perform at an economically feasible level. This study describes an additional tool to modify central metabolism and direct metabolic flux to a product. We have shown that variants of the pyruvate dehydrogenase complex can direct metabolic flux away from cell growth to increase pyruvate production in Escherichia coli. This approach could be paired with existing strategies to optimize metabolism and create industrially relevant and economically feasible processes.
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Affiliation(s)
- W. Chris Moxley
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
| | - Mark A. Eiteman
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
- School of Chemical, Materials and Biomedical Engineering, University of Georgia, Athens, Georgia, USA
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8
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The Development of Bacteriophage Resistance in Vibrio alginolyticus Depends on a Complex Metabolic Adaptation Strategy. Viruses 2021; 13:v13040656. [PMID: 33920240 PMCID: PMC8069663 DOI: 10.3390/v13040656] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 04/07/2021] [Accepted: 04/08/2021] [Indexed: 12/23/2022] Open
Abstract
Lytic bacteriophages have been well documented to play a pivotal role in microbial ecology due to their complex interactions with bacterial species, especially in aquatic habitats. Although the use of phages as antimicrobial agents, known as phage therapy, in the aquatic environment has been increasing, recent research has revealed drawbacks due to the development of phage-resistant strains among Gram-negative species. Acquired phage resistance in marine Vibrios has been proven to be a very complicated process utilizing biochemical, metabolic, and molecular adaptation strategies. The results of our multi-omics approach, incorporating transcriptome and metabolome analyses of Vibrio alginolyticus phage-resistant strains, corroborate this prospect. Our results provide insights into phage-tolerant strains diminishing the expression of phage receptors ompF, lamB, and btuB. The same pattern was observed for genes encoding natural nutrient channels, such as rbsA, ptsG, tryP, livH, lysE, and hisp, meaning that the cell needs to readjust its biochemistry to achieve phage resistance. The results showed reprogramming of bacterial metabolism by transcript regulations in key-metabolic pathways, such as the tricarboxylic acid cycle (TCA) and lysine biosynthesis, as well as the content of intracellular metabolites belonging to processes that could also significantly affect the cell physiology. Finally, SNP analysis in resistant strains revealed no evidence of amino acid alterations in the studied putative bacterial phage receptors, but several SNPs were detected in genes involved in transcriptional regulation. This phenomenon appears to be a phage-specific, fine-tuned metabolic engineering, imposed by the different phage genera the bacteria have interacted with, updating the role of lytic phages in microbial marine ecology.
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Barron MR, Cieza RJ, Hill DR, Huang S, Yadagiri VK, Spence JR, Young VB. The Lumen of Human Intestinal Organoids Poses Greater Stress to Bacteria Compared to the Germ-Free Mouse Intestine: Escherichia coli Deficient in RpoS as a Colonization Probe. mSphere 2020; 5:e00777-20. [PMID: 33177212 PMCID: PMC7657587 DOI: 10.1128/msphere.00777-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 10/23/2020] [Indexed: 02/07/2023] Open
Abstract
Pluripotent stem-cell-derived human intestinal organoids (HIOs) are three-dimensional, multicellular structures that model a naive intestinal epithelium in an in vitro system. Several published reports have investigated the use of HIOs to study host-microbe interactions. We recently demonstrated that microinjection of the nonpathogenic Escherichia coli strain ECOR2 into HIOs induced morphological and functional maturation of the HIO epithelium, including increased secretion of mucins and cationic antimicrobial peptides. In the current work, we use ECOR2 as a biological probe to further characterize the environment present in the HIO lumen. We generated an isogenic mutant in the general stress response sigma factor RpoS and employed this mutant to compare challenges faced by a bacterium during colonization of the HIO lumen relative to the germ-free mouse intestine. We demonstrate that the loss of RpoS significantly decreases the ability of ECOR2 to colonize HIOs, although it does not prevent colonization of germ-free mice. These results indicate that the HIO lumen is a more restrictive environment to E. coli than the germ-free mouse intestine, thus increasing our understanding of the HIO model system as it pertains to studying the establishment of intestinal host-microbe symbioses.IMPORTANCE Technological advancements have driven and will continue to drive the adoption of organotypic systems for investigating host-microbe interactions within the human intestinal ecosystem. Using E. coli deficient in the RpoS-mediated general stress response, we demonstrate that the type or severity of microbial stressors within the HIO lumen is more restrictive than those of the in vivo environment of the germ-free mouse gut. This study provides important insight into the nature of the HIO microenvironment from a microbiological standpoint.
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Affiliation(s)
- Madeline R Barron
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Roberto J Cieza
- Department of Internal Medicine, Division of Infectious Diseases, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - David R Hill
- Department of Internal Medicine, Division of Gastroenterology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Sha Huang
- Department of Internal Medicine, Division of Gastroenterology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Veda K Yadagiri
- Department of Internal Medicine, Division of Infectious Diseases, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Jason R Spence
- Department of Internal Medicine, Division of Gastroenterology, University of Michigan Medical School, Ann Arbor, Michigan, USA
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan, USA
- Department of Biomedical Engineering, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Vincent B Young
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
- Department of Internal Medicine, Division of Infectious Diseases, University of Michigan Medical School, Ann Arbor, Michigan, USA
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10
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Roussel C, De Paepe K, Galia W, De Bodt J, Chalancon S, Leriche F, Ballet N, Denis S, Alric M, Van de Wiele T, Blanquet-Diot S. Spatial and temporal modulation of enterotoxigenic E. coli H10407 pathogenesis and interplay with microbiota in human gut models. BMC Biol 2020; 18:141. [PMID: 33054775 PMCID: PMC7559199 DOI: 10.1186/s12915-020-00860-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 08/31/2020] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Enterotoxigenic Escherichia coli (ETEC) substantially contributes to the burden of diarrheal illnesses in developing countries. With the use of complementary in vitro models of the human digestive environment, TNO gastrointestinal model (TIM-1), and Mucosal Simulator of the Human Intestinal Microbial Ecosystem (M-SHIME), we provided the first detailed report on the spatial-temporal modulation of ETEC H10407 survival, virulence, and its interplay with gut microbiota. These systems integrate the main physicochemical parameters of the human upper digestion (TIM-1) and simulate the ileum vs ascending colon microbial communities and luminal vs mucosal microenvironments, captured from six fecal donors (M-SHIME). RESULTS A loss of ETEC viability was noticed upon gastric digestion, while a growth renewal was found at the end of jejunal and ileal digestion. The remarkable ETEC mucosal attachment helped to maintain luminal concentrations above 6 log10 mL-1 in the ileum and ascending colon up to 5 days post-infection. Seven ETEC virulence genes were monitored. Most of them were switched on in the stomach and switched off in the TIM-1 ileal effluents and in a late post-infectious stage in the M-SHIME ascending colon. No heat-labile enterotoxin production was measured in the stomach in contrast to the ileum and ascending colon. Using 16S rRNA gene-based amplicon sequencing, ETEC infection modulated the microbial community structure of the ileum mucus and ascending colon lumen. CONCLUSIONS This study provides a better understanding of the interplay between ETEC and gastrointestinal cues and may serve to complete knowledge on ETEC pathogenesis and inspire novel prophylactic strategies for diarrheal diseases.
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Affiliation(s)
- Charlène Roussel
- Université Clermont Auvergne, UMR UCA-INRA 454 MEDIS, Microbiology Digestive Environment and Health, Clermont-Ferrand, France.,CMET, Center for Microbial Ecology and Technology, Department of Biotechnology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Kim De Paepe
- CMET, Center for Microbial Ecology and Technology, Department of Biotechnology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Wessam Galia
- UMR 5557 Microbial Ecology, Research Group on Bacterial Opportunistic Pathogens and Environment, CNRS, VetAgro Sup, Lyon, France
| | - Jana De Bodt
- CMET, Center for Microbial Ecology and Technology, Department of Biotechnology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Sandrine Chalancon
- Université Clermont Auvergne, UMR UCA-INRA 454 MEDIS, Microbiology Digestive Environment and Health, Clermont-Ferrand, France
| | | | - Nathalie Ballet
- Lesaffre International, Lesaffre Group, Marcq-en-Baroeul, France
| | - Sylvain Denis
- Université Clermont Auvergne, UMR UCA-INRA 454 MEDIS, Microbiology Digestive Environment and Health, Clermont-Ferrand, France
| | - Monique Alric
- Université Clermont Auvergne, UMR UCA-INRA 454 MEDIS, Microbiology Digestive Environment and Health, Clermont-Ferrand, France
| | - Tom Van de Wiele
- CMET, Center for Microbial Ecology and Technology, Department of Biotechnology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium.
| | - Stéphanie Blanquet-Diot
- Université Clermont Auvergne, UMR UCA-INRA 454 MEDIS, Microbiology Digestive Environment and Health, Clermont-Ferrand, France.
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11
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Gayán E, Van den Bergh B, Michiels J, Michiels CW, Aertsen A. Synthetic reconstruction of extreme high hydrostatic pressure resistance in Escherichia coli. Metab Eng 2020; 62:287-297. [PMID: 32979485 DOI: 10.1016/j.ymben.2020.09.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 09/18/2020] [Accepted: 09/21/2020] [Indexed: 12/17/2022]
Abstract
Although high hydrostatic pressure (HHP) is an interesting parameter to be applied in bioprocessing, its potential is currently limited by the lack of bacterial chassis capable of surviving and maintaining homeostasis under pressure. While several efforts have been made to genetically engineer microorganisms able to grow at sublethal pressures, there is little information for designing backgrounds that survive more extreme pressures. In this investigation, we analyzed the genome of an extreme HHP-resistant mutant of E. coli MG1655 (designated as DVL1), from which we identified four mutations (in the cra, cyaA, aceA and rpoD loci) causally linked to increased HHP resistance. Analysing the functional effect of these mutations we found that the coupled effect of downregulation of cAMP/CRP, Cra and the glyoxylate shunt activity, together with the upregulation of RpoH and RpoS activity, could mechanistically explain the increased HHP resistance of the mutant. Using combinations of three mutations, we could synthetically engineer E. coli strains able to comfortably survive pressures of 600-800 MPa, which could serve as genetic backgrounds for HHP-based biotechnological applications.
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Affiliation(s)
- Elisa Gayán
- Department of Microbial and Molecular Systems, KU Leuven. Faculty of Bioscience Engineering, Kasteelpark Arenberg 20, 3001, Leuven, Belgium.
| | - Bram Van den Bergh
- Department of Microbial and Molecular Systems, KU Leuven. Faculty of Bioscience Engineering, Kasteelpark Arenberg 20, 3001, Leuven, Belgium; VIB Center for Microbiology, Flanders Institute for Biotechnology, Kasteelpark Arenberg 20, 3001, Leuven, Belgium
| | - Jan Michiels
- Department of Microbial and Molecular Systems, KU Leuven. Faculty of Bioscience Engineering, Kasteelpark Arenberg 20, 3001, Leuven, Belgium; VIB Center for Microbiology, Flanders Institute for Biotechnology, Kasteelpark Arenberg 20, 3001, Leuven, Belgium
| | - Chris W Michiels
- Department of Microbial and Molecular Systems, KU Leuven. Faculty of Bioscience Engineering, Kasteelpark Arenberg 20, 3001, Leuven, Belgium
| | - Abram Aertsen
- Department of Microbial and Molecular Systems, KU Leuven. Faculty of Bioscience Engineering, Kasteelpark Arenberg 20, 3001, Leuven, Belgium.
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12
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Bacterial Glycogen Provides Short-Term Benefits in Changing Environments. Appl Environ Microbiol 2020; 86:AEM.00049-20. [PMID: 32111592 DOI: 10.1128/aem.00049-20] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 02/26/2020] [Indexed: 11/20/2022] Open
Abstract
Changing nutritional conditions challenge microbes and shape their evolutionary optimization. Here, we used real-time metabolomics to investigate the role of glycogen in the dynamic physiological adaptation of Escherichia coli to fluctuating nutrients following carbon starvation. After the depletion of environmental glucose, we found significant metabolic activity remaining, which was linked to rapid utilization of intracellular glycogen. Glycogen was depleted by 80% within minutes of glucose starvation and was similarly replenished within minutes of glucose availability. These fast time scales of glycogen utilization correspond to the short-term benefits that glycogen provided to cells undergoing various physiological transitions. Cells capable of utilizing glycogen exhibited shorter lag times than glycogen mutants when starved between periods of exposure to different carbon sources. The ability to utilize glycogen was also important for the transition between planktonic and biofilm lifestyles and enabled increased glucose uptake during pulses of limited glucose availability. While wild-type and mutant strains exhibited comparable growth rates in steady environments, mutants deficient in glycogen utilization grew more poorly in environments that fluctuated on minute scales between carbon availability and starvation. Taken together, these results highlight an underappreciated role of glycogen in rapidly providing carbon and energy in changing environments, thereby increasing survival and competition capabilities under fluctuating and nutrient-poor conditions.IMPORTANCE Nothing is constant in life, and microbes in particular have to adapt to frequent and rapid environmental changes. Here, we used real-time metabolomics and single-cell imaging to demonstrate that the internal storage polymer glycogen plays a crucial role in such dynamic adaptations. Glycogen is depleted within minutes of glucose starvation and similarly is replenished within minutes of glucose availability. Cells capable of utilizing glycogen exhibited shorter lag times than glycogen mutants when starved between periods of exposure to different carbon sources. While wild-type and mutant strains exhibited comparable growth rates in steady environments, mutants deficient in glycogen utilization grew more poorly in environments that fluctuated on minute scales between carbon availability and starvation. These results highlight an underappreciated role of glycogen in rapidly providing carbon and energy in changing environments, thereby increasing survival and competition capabilities under fluctuating and nutrient-poor conditions.
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13
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Campos AI, Zampieri M. Metabolomics-Driven Exploration of the Chemical Drug Space to Predict Combination Antimicrobial Therapies. Mol Cell 2019; 74:1291-1303.e6. [PMID: 31047795 PMCID: PMC6591011 DOI: 10.1016/j.molcel.2019.04.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 12/27/2018] [Accepted: 03/28/2019] [Indexed: 01/12/2023]
Abstract
Alternative to the conventional search for single-target, single-compound treatments, combination therapies can open entirely new opportunities to fight antibiotic resistance. However, combinatorial complexity prohibits experimental testing of drug combinations on a large scale, and methods to rationally design combination therapies are lagging behind. Here, we developed a combined experimental-computational approach to predict drug-drug interactions using high-throughput metabolomics. The approach was tested on 1,279 pharmacologically diverse drugs applied to the gram-negative bacterium Escherichia coli. Combining our metabolic profiling of drug response with previously generated metabolic and chemogenomic profiles of 3,807 single-gene deletion strains revealed an unexpectedly large space of inhibited gene functions and enabled rational design of drug combinations. This approach is applicable to other therapeutic areas and can unveil unprecedented insights into drug tolerance, side effects, and repurposing. The compendium of drug-associated metabolome profiles is available at https://zampierigroup.shinyapps.io/EcoPrestMet, providing a valuable resource for the microbiological and pharmacological communities.
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Affiliation(s)
- Adrian I Campos
- Institute of Molecular Systems Biology, ETH Zurich, Otto-Stern-Weg 3, 8093 Zurich, Switzerland
| | - Mattia Zampieri
- Institute of Molecular Systems Biology, ETH Zurich, Otto-Stern-Weg 3, 8093 Zurich, Switzerland.
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14
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Enhanced production of poly‑3‑hydroxybutyrate (PHB) by expression of response regulator DR1558 in recombinant Escherichia coli. Int J Biol Macromol 2019; 131:29-35. [DOI: 10.1016/j.ijbiomac.2019.03.044] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2019] [Revised: 03/04/2019] [Accepted: 03/06/2019] [Indexed: 01/14/2023]
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15
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Regulation of Global Transcription in Escherichia coli by Rsd and 6S RNA. G3-GENES GENOMES GENETICS 2018; 8:2079-2089. [PMID: 29686109 PMCID: PMC5982834 DOI: 10.1534/g3.118.200265] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
In Escherichia coli, the sigma factor σ70 directs RNA polymerase to transcribe growth-related genes, while σ38 directs transcription of stress response genes during stationary phase. Two molecules hypothesized to regulate RNA polymerase are the protein Rsd, which binds to σ70, and the non-coding 6S RNA which binds to the RNA polymerase-σ70 holoenzyme. Despite multiple studies, the functions of Rsd and 6S RNA remain controversial. Here we use RNA-Seq in five phases of growth to elucidate their function on a genome-wide scale. We show that Rsd and 6S RNA facilitate σ38 activity throughout bacterial growth, while 6S RNA also regulates widely different genes depending upon growth phase. We discover novel interactions between 6S RNA and Rsd and show widespread expression changes in a strain lacking both regulators. Finally, we present a mathematical model of transcription which highlights the crosstalk between Rsd and 6S RNA as a crucial factor in controlling sigma factor competition and global gene expression.
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16
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Du ZQ, Zhang Y, Qian ZG, Xiao H, Zhong JJ. Combination of traditional mutation and metabolic engineering to enhance ansamitocin P-3 production in Actinosynnema pretiosum. Biotechnol Bioeng 2017; 114:2794-2806. [DOI: 10.1002/bit.26396] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 07/26/2017] [Accepted: 08/02/2017] [Indexed: 12/31/2022]
Affiliation(s)
- Zhi-Qiang Du
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, and Laboratory of Molecular Biochemical Engineering and Advanced Fermentation Technology, Department of Bioengineering, School of Life Sciences and Biotechnology; Shanghai Jiao Tong University; Shanghai China
| | - Yuan Zhang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, and Laboratory of Molecular Biochemical Engineering and Advanced Fermentation Technology, Department of Bioengineering, School of Life Sciences and Biotechnology; Shanghai Jiao Tong University; Shanghai China
| | - Zhi-Gang Qian
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, and Laboratory of Molecular Biochemical Engineering and Advanced Fermentation Technology, Department of Bioengineering, School of Life Sciences and Biotechnology; Shanghai Jiao Tong University; Shanghai China
| | - Han Xiao
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, and Laboratory of Molecular Biochemical Engineering and Advanced Fermentation Technology, Department of Bioengineering, School of Life Sciences and Biotechnology; Shanghai Jiao Tong University; Shanghai China
| | - Jian-Jiang Zhong
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, and Laboratory of Molecular Biochemical Engineering and Advanced Fermentation Technology, Department of Bioengineering, School of Life Sciences and Biotechnology; Shanghai Jiao Tong University; Shanghai China
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17
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Suppression of the Escherichia coli dnaA46 mutation by changes in the activities of the pyruvate-acetate node links DNA replication regulation to central carbon metabolism. PLoS One 2017; 12:e0176050. [PMID: 28448512 PMCID: PMC5407757 DOI: 10.1371/journal.pone.0176050] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 04/04/2017] [Indexed: 02/06/2023] Open
Abstract
To ensure faithful transmission of genetic material to progeny cells, DNA replication is tightly regulated, mainly at the initiation step. Escherichia coli cells regulate the frequency of initiation according to growth conditions. Results of the classical, as well as the latest studies, suggest that the DNA replication in E. coli starts at a predefined, constant cell volume per chromosome but the mechanisms coordinating DNA replication with cell growth are still not fully understood. Results of recent investigations have revealed a role of metabolic pathway proteins in the control of cell division and a direct link between metabolism and DNA replication has also been suggested both in Bacillus subtilis and E. coli cells. In this work we show that defects in the acetate overflow pathway suppress the temperature-sensitivity of a defective replication initiator–DnaA under acetogenic growth conditions. Transcriptomic and metabolic analyses imply that this suppression is correlated with pyruvate accumulation, resulting from alterations in the pyruvate dehydrogenase (PDH) activity. Consequently, deletion of genes encoding the pyruvate dehydrogenase subunits likewise resulted in suppression of the thermal-sensitive growth of the dnaA46 strain. We propose that the suppressor effect may be directly related to the PDH complex activity, providing a link between an enzyme of the central carbon metabolism and DNA replication.
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18
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Groot J, Cepress-Mclean SC, Robbins-Pianka A, Knight R, Gill RT. Multiplex growth rate phenotyping of synthetic mutants in selection to engineer glucose and xylose co-utilization in Escherichia coli. Biotechnol Bioeng 2016; 114:885-893. [PMID: 27861733 DOI: 10.1002/bit.26217] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 11/02/2016] [Accepted: 11/06/2016] [Indexed: 12/25/2022]
Abstract
Engineering the simultaneous consumption of glucose and xylose sugars is critical to enable the sustainable production of biofuels from lignocellulosic biomass. In most major industrial microorganisms glucose completely inhibits the uptake of xylose, limiting efficient sugar mixture conversion. In E. coli removal of the major glucose transporter PTS allows for glucose and xylose co-consumption but only after prolonged adaptation, which is an effective process but hard to control and prone to co-evolving undesired traits. Here we synthetically engineer mutants to target sugar co-consumption properties; we subject a PTS- mutant to a short adaptive step and subsequently either delete or overexpress key genes previously suggested to affect sugar consumption. Screening the co-consumption properties of these mutants individually is very laborious. We show we can evaluate sugar co-consumption properties in parallel by culturing the mutants in selection and applying a novel approach that computes mutant growth rates in selection using chromosomal barcode counts obtained from Next-Generation Sequencing. We validate this multiplex growth rate phenotyping approach with individual mutant pure cultures, identify new instances of mutants cross-feeding on metabolic byproducts, and, importantly, find that the rates of glucose and xylose co-consumption can be tuned by altering glucokinase expression in our PTS- background. Biotechnol. Bioeng. 2017;114: 885-893. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Joost Groot
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, Colorado
| | - Sidney C Cepress-Mclean
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, Colorado
| | | | - Rob Knight
- Biofrontiers Institute, University of Colorado, Boulder, Colorado
| | - Ryan T Gill
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, Colorado
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19
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Effects of σ factor competition are promoter initiation kinetics dependent. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2016; 1859:1281-8. [DOI: 10.1016/j.bbagrm.2016.07.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 07/05/2016] [Accepted: 07/07/2016] [Indexed: 01/29/2023]
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20
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Jahan N, Maeda K, Matsuoka Y, Sugimoto Y, Kurata H. Development of an accurate kinetic model for the central carbon metabolism of Escherichia coli. Microb Cell Fact 2016; 15:112. [PMID: 27329289 PMCID: PMC4915146 DOI: 10.1186/s12934-016-0511-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 06/08/2016] [Indexed: 01/17/2023] Open
Abstract
Background A kinetic model provides insights into the dynamic response of biological systems and predicts how their complex metabolic and gene regulatory networks generate particular functions. Of many biological systems, Escherichia coli metabolic pathways have been modeled extensively at the enzymatic and genetic levels, but existing models cannot accurately reproduce experimental behaviors in a batch culture, due to the inadequate estimation of a specific cell growth rate and a large number of unmeasured parameters. Results In this study, we developed a detailed kinetic model for the central carbon metabolism of E. coli in a batch culture, which includes the glycolytic pathway, tricarboxylic acid cycle, pentose phosphate pathway, Entner-Doudoroff pathway, anaplerotic pathway, glyoxylate shunt, oxidative phosphorylation, phosphotransferase system (Pts), non-Pts and metabolic gene regulations by four protein transcription factors: cAMP receptor, catabolite repressor/activator, pyruvate dehydrogenase complex repressor and isocitrate lyase regulator. The kinetic parameters were estimated by a constrained optimization method on a supercomputer. The model estimated a specific growth rate based on reaction kinetics and accurately reproduced the dynamics of wild-type E. coli and multiple genetic mutants in a batch culture. Conclusions This model overcame the intrinsic limitations of existing kinetic models in a batch culture, predicted the effects of multilayer regulations (allosteric effectors and gene expression) on central carbon metabolism and proposed rationally designed fast-growing cells based on understandings of molecular processes. Electronic supplementary material The online version of this article (doi:10.1186/s12934-016-0511-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Nusrat Jahan
- Department of Bioscience and Bioinformatics, Kyushu Institute of Technology, 680-4 Kawazu, Iizuka, Fukuoka, 820-8502, Japan
| | - Kazuhiro Maeda
- Frontier Research Academy for Young Researchers, Kyushu Institute of Technology, 1-1 Sensui-cho, Tobata, Kitakyushu, Fukuoka, 804-8550, Japan.,Biomedical Informatics R&D Center, Kyushu Institute of Technology, 680-4 Kawazu, Iizuka, Fukuoka, 820-8502, Japan
| | - Yu Matsuoka
- Department of Bioscience and Bioinformatics, Kyushu Institute of Technology, 680-4 Kawazu, Iizuka, Fukuoka, 820-8502, Japan
| | - Yurie Sugimoto
- Department of Bioscience and Bioinformatics, Kyushu Institute of Technology, 680-4 Kawazu, Iizuka, Fukuoka, 820-8502, Japan
| | - Hiroyuki Kurata
- Department of Bioscience and Bioinformatics, Kyushu Institute of Technology, 680-4 Kawazu, Iizuka, Fukuoka, 820-8502, Japan. .,Biomedical Informatics R&D Center, Kyushu Institute of Technology, 680-4 Kawazu, Iizuka, Fukuoka, 820-8502, Japan.
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Abstract
Early research on the origins and mechanisms of mutation led to the establishment of the dogma that, in the absence of external forces, spontaneous mutation rates are constant. However, recent results from a variety of experimental systems suggest that mutation rates can increase in response to selective pressures. This chapter summarizes data demonstrating that,under stressful conditions, Escherichia coli and Salmonella can increase the likelihood of beneficial mutations by modulating their potential for genetic change.Several experimental systems used to study stress-induced mutagenesis are discussed, with special emphasison the Foster-Cairns system for "adaptive mutation" in E. coli and Salmonella. Examples from other model systems are given to illustrate that stress-induced mutagenesis is a natural and general phenomenon that is not confined to enteric bacteria. Finally, some of the controversy in the field of stress-induced mutagenesis is summarized and discussed, and a perspective on the current state of the field is provided.
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22
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Mahalik S, Sharma AK, Mukherjee KJ. Genome engineering for improved recombinant protein expression in Escherichia coli. Microb Cell Fact 2014; 13:177. [PMID: 25523647 PMCID: PMC4300154 DOI: 10.1186/s12934-014-0177-1] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Accepted: 12/05/2014] [Indexed: 01/09/2023] Open
Abstract
A metabolic engineering perspective which views recombinant protein
expression as a multistep pathway allows us to move beyond vector design and
identify the downstream rate limiting steps in expression. In E.coli these are typically at the translational level
and the supply of precursors in the form of energy, amino acids and nucleotides.
Further recombinant protein production triggers a global cellular stress response
which feedback inhibits both growth and product formation. Countering this requires
a system level analysis followed by a rational host cell engineering to sustain
expression for longer time periods. Another strategy to increase protein yields
could be to divert the metabolic flux away from biomass formation and towards
recombinant protein production. This would require a growth stoppage mechanism which
does not affect the metabolic activity of the cell or the transcriptional or
translational efficiencies. Finally cells have to be designed for efficient export
to prevent buildup of proteins inside the cytoplasm and also simplify downstream
processing. The rational and the high throughput strategies that can be used for the
construction of such improved host cell platforms for recombinant protein expression
is the focus of this review.
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Affiliation(s)
- Shubhashree Mahalik
- School of Biotechnology, Jawaharlal Nehru University, New Delhi, 110067, India.
| | - Ashish K Sharma
- School of Biotechnology, Jawaharlal Nehru University, New Delhi, 110067, India.
| | - Krishna J Mukherjee
- School of Biotechnology, Jawaharlal Nehru University, New Delhi, 110067, India.
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23
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Saxer G, Krepps MD, Merkley ED, Ansong C, Deatherage Kaiser BL, Valovska MT, Ristic N, Yeh PT, Prakash VP, Leiser OP, Nakhleh L, Gibbons HS, Kreuzer HW, Shamoo Y. Mutations in global regulators lead to metabolic selection during adaptation to complex environments. PLoS Genet 2014; 10:e1004872. [PMID: 25501822 PMCID: PMC4263409 DOI: 10.1371/journal.pgen.1004872] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 11/04/2014] [Indexed: 01/12/2023] Open
Abstract
Adaptation to ecologically complex environments can provide insights into the evolutionary dynamics and functional constraints encountered by organisms during natural selection. Adaptation to a new environment with abundant and varied resources can be difficult to achieve by small incremental changes if many mutations are required to achieve even modest gains in fitness. Since changing complex environments are quite common in nature, we investigated how such an epistatic bottleneck can be avoided to allow rapid adaptation. We show that adaptive mutations arise repeatedly in independently evolved populations in the context of greatly increased genetic and phenotypic diversity. We go on to show that weak selection requiring substantial metabolic reprogramming can be readily achieved by mutations in the global response regulator arcA and the stress response regulator rpoS. We identified 46 unique single-nucleotide variants of arcA and 18 mutations in rpoS, nine of which resulted in stop codons or large deletions, suggesting that subtle modulations of ArcA function and knockouts of rpoS are largely responsible for the metabolic shifts leading to adaptation. These mutations allow a higher order metabolic selection that eliminates epistatic bottlenecks, which could occur when many changes would be required. Proteomic and carbohydrate analysis of adapting E. coli populations revealed an up-regulation of enzymes associated with the TCA cycle and amino acid metabolism, and an increase in the secretion of putrescine. The overall effect of adaptation across populations is to redirect and efficiently utilize uptake and catabolism of abundant amino acids. Concomitantly, there is a pronounced spread of more ecologically limited strains that results from specialization through metabolic erosion. Remarkably, the global regulators arcA and rpoS can provide a “one-step” mechanism of adaptation to a novel environment, which highlights the importance of global resource management as a powerful strategy to adaptation. Changing environmental conditions are the norm in biology. However, understanding adaptation to complex environments presents many challenges. For example, adaptation to resource-rich environments can potentially have many successful evolutionary trajectories to increased fitness. Even in conditions of plenty, the utilization of numerous but novel resources can require multiple mutations before a benefit is accrued. We evolved two bacterial species isolated from the gut of healthy humans in two different, resource-rich media commonly used in the laboratory. We anticipated that under weak selection the population would evolve tremendous genetic diversity. Despite such a complex genetic background we were able to identify a strong degree of parallel evolution and using a combination of population proteomic and population genomic approaches we show that two global regulators, arcA and rpoS, are the principle targets of selection. Up-regulation of the different metabolic pathways that are controlled by these global regulators in combination with up-regulation of transporters that transport nutrients into the cell revealed increased use of the novel resources. Thus global regulators can provide a one-step model to shift metabolism efficiently and provide rapid a one-step reprogramming of the cell metabolic profile.
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Affiliation(s)
- Gerda Saxer
- Department of BioSciences, Rice University, Houston, Texas, United States of America
- * E-mail: (GS); (YS)
| | - Michael D. Krepps
- United States Army Edgewood Chemical Biological Center, Aberdeen Proving Ground, Maryland, United States of America
- EXCET, Inc, Springfield, Virginia, United States of America
| | - Eric D. Merkley
- Pacific Northwest National Laboratory, Richland, Washington, United States of America
| | - Charles Ansong
- Pacific Northwest National Laboratory, Richland, Washington, United States of America
| | | | | | - Nikola Ristic
- Department of Computer Science, Rice University, Houston, Texas, United States of America
| | - Ping T. Yeh
- Department of BioSciences, Rice University, Houston, Texas, United States of America
| | - Vittal P. Prakash
- Department of BioSciences, Rice University, Houston, Texas, United States of America
| | - Owen P. Leiser
- Center for Microbial Genetics and Genomics, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Luay Nakhleh
- Department of Computer Science, Rice University, Houston, Texas, United States of America
| | - Henry S. Gibbons
- United States Army Edgewood Chemical Biological Center, Aberdeen Proving Ground, Maryland, United States of America
| | - Helen W. Kreuzer
- Pacific Northwest National Laboratory, Richland, Washington, United States of America
| | - Yousif Shamoo
- Department of BioSciences, Rice University, Houston, Texas, United States of America
- * E-mail: (GS); (YS)
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Tripathi L, Zhang Y, Lin Z. Bacterial sigma factors as targets for engineered or synthetic transcriptional control. Front Bioeng Biotechnol 2014; 2:33. [PMID: 25232540 PMCID: PMC4153023 DOI: 10.3389/fbioe.2014.00033] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Accepted: 08/20/2014] [Indexed: 11/20/2022] Open
Abstract
Sigma (σ) factors are the predominant constituents of transcription regulation in bacteria. σ Factors recruit the core RNA polymerase to recognize promoters with specific DNA sequences. Recently, engineering of transcriptional regulators has become a significant tool for strain engineering. The present review summarizes the recent advances in σ factor based engineering or synthetic design. The manipulation of σ factors presents insights into the bacterial stress tolerance and metabolite productivity. We envision more synthetic design based on σ factors that can be used to tune the regulatory network of bacteria.
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Affiliation(s)
- Lakshmi Tripathi
- Department of Chemical Engineering, Tsinghua University , Beijing , China
| | - Yan Zhang
- Department of Chemical Engineering, Tsinghua University , Beijing , China
| | - Zhanglin Lin
- Department of Chemical Engineering, Tsinghua University , Beijing , China
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25
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Abstract
ABSTRACT: Bacterial adaptation to suboptimal nutrient environments, including host and/or extreme environments, is subject to complex, coordinated control involving many proteins and RNAs. Among the γ-proteobacteria, which includes many pathogens, the RpoS regulon has been a key focus for many years. Although the RpoS regulator was first identified as a growth phase-dependent regulator, our current understanding of RpoS is now more nuanced as this central regulator also has roles in exponential phase, biofilm development, bacterial virulence and bacterial persistence, as well as in stress adaptation. Induction of RpoS can also exert substantial metabolic effects by negatively regulating key systems including flagella biosynthesis, cryptic phage gene expression and the tricarboxylic acid cycle. Although core RpoS-controlled metabolic functions are conserved, there are substantial differences in RpoS regulation even among closely related bacteria, indicating that regulatory plasticity may be an important aspect of RpoS regulation, which is important in evolutionary adaptation to specialized environments.
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Affiliation(s)
- Herb E Schellhorn
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada
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26
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Khemiri A, Carrière M, Bremond N, Ben Mlouka MA, Coquet L, Llorens I, Chapon V, Jouenne T, Cosette P, Berthomieu C. Escherichia coli response to uranyl exposure at low pH and associated protein regulations. PLoS One 2014; 9:e89863. [PMID: 24587082 PMCID: PMC3935937 DOI: 10.1371/journal.pone.0089863] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Accepted: 01/23/2014] [Indexed: 11/18/2022] Open
Abstract
Better understanding of uranyl toxicity in bacteria is necessary to optimize strains for bioremediation purposes or for using bacteria as biodetectors for bioavailable uranyl. In this study, after different steps of optimization, Escherichia colicells were exposed to uranyl at low pH to minimize uranyl precipitation and to increase its bioavailability. Bacteria were adapted to mid acidic pH before exposure to 50 or 80 µM uranyl acetate for two hours at pH≈3. To evaluate the impact of uranium, growth in these conditions were compared and the same rates of cells survival were observed in control and uranyl exposed cultures. Additionally, this impact was analyzedby two-dimensional differential gel electrophoresis proteomics to discover protein actors specifically present or accumulated in contact with uranium.Exposure to uranium resulted in differential accumulation of proteins associated with oxidative stress and in the accumulation of the NADH/quinone oxidoreductase WrbA. This FMN dependent protein performs obligate two-electron reduction of quinones, and may be involved in cells response to oxidative stress. Interestingly, this WrbA protein presents similarities with the chromate reductase from E. coli, which was shown to reduce uranyl in vitro.
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Affiliation(s)
- Arbia Khemiri
- CEA, DSV, IBEB, Commissariat à l'Energie Atomique, Laboratoire des Interactions Protéine-Métal, Saint-Paul-lez-Durance, France ; CNRS, UMR Biologie Végétale et Microbiologie Environnementales 7265, Saint-Paul-lez-Durance, France ; Université d'Aix-Marseille, Saint-Paul-lez-Durance, France
| | - Marie Carrière
- UMR E3 CEA-Université Joseph Fourier, Service de Chimie Inorganique et Biologique, Laboratoire Lésions des Acides Nucléiques (LAN), Grenoble, France
| | - Nicolas Bremond
- CEA, DSV, IBEB, Commissariat à l'Energie Atomique, Laboratoire des Interactions Protéine-Métal, Saint-Paul-lez-Durance, France ; CNRS, UMR Biologie Végétale et Microbiologie Environnementales 7265, Saint-Paul-lez-Durance, France ; Université d'Aix-Marseille, Saint-Paul-lez-Durance, France
| | - Mohamed Amine Ben Mlouka
- UMR 6270 CNRS, Plateforme Protéomique PISSARO, IRIB -Université de Rouen, Mont Saint Aignan, France
| | - Laurent Coquet
- UMR 6270 CNRS, Plateforme Protéomique PISSARO, IRIB -Université de Rouen, Mont Saint Aignan, France
| | - Isabelle Llorens
- ESRF-CRG-FAME beamline, Polygone Scientifique Louis Néel, Grenoble, France ; Commissariat à l'Energie Atomique CEA, DSM, INAC, Laboratoire Nanostructure et Rayonnement Synchrotron, Grenoble, France
| | - Virginie Chapon
- CEA, DSV, IBEB, Commissariat à l'Energie Atomique, Laboratoire des Interactions Protéine-Métal, Saint-Paul-lez-Durance, France ; CNRS, UMR Biologie Végétale et Microbiologie Environnementales 7265, Saint-Paul-lez-Durance, France ; Université d'Aix-Marseille, Saint-Paul-lez-Durance, France
| | - Thierry Jouenne
- UMR 6270 CNRS, Plateforme Protéomique PISSARO, IRIB -Université de Rouen, Mont Saint Aignan, France
| | - Pascal Cosette
- UMR 6270 CNRS, Plateforme Protéomique PISSARO, IRIB -Université de Rouen, Mont Saint Aignan, France
| | - Catherine Berthomieu
- CEA, DSV, IBEB, Commissariat à l'Energie Atomique, Laboratoire des Interactions Protéine-Métal, Saint-Paul-lez-Durance, France ; CNRS, UMR Biologie Végétale et Microbiologie Environnementales 7265, Saint-Paul-lez-Durance, France ; Université d'Aix-Marseille, Saint-Paul-lez-Durance, France
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27
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Regulation Systems of Bacteria such as Escherichia coli in Response to Nutrient Limitation and Environmental Stresses. Metabolites 2013; 4:1-35. [PMID: 24958385 PMCID: PMC4018673 DOI: 10.3390/metabo4010001] [Citation(s) in RCA: 123] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Revised: 11/18/2013] [Accepted: 12/06/2013] [Indexed: 11/16/2022] Open
Abstract
An overview was made to understand the regulation system of a bacterial cell such as Escherichia coli in response to nutrient limitation such as carbon, nitrogen, phosphate, sulfur, ion sources, and environmental stresses such as oxidative stress, acid shock, heat shock, and solvent stresses. It is quite important to understand how the cell detects environmental signals, integrate such information, and how the cell system is regulated. As for catabolite regulation, F1,6B P (FDP), PEP, and PYR play important roles in enzyme level regulation together with transcriptional regulation by such transcription factors as Cra, Fis, CsrA, and cAMP-Crp. αKG plays an important role in the coordinated control between carbon (C)- and nitrogen (N)-limitations, where αKG inhibits enzyme I (EI) of phosphotransferase system (PTS), thus regulating the glucose uptake rate in accordance with N level. As such, multiple regulation systems are co-ordinated for the cell synthesis and energy generation against nutrient limitations and environmental stresses. As for oxidative stress, the TCA cycle both generates and scavenges the reactive oxygen species (ROSs), where NADPH produced at ICDH and the oxidative pentose phosphate pathways play an important role in coping with oxidative stress. Solvent resistant mechanism was also considered for the stresses caused by biofuels and biochemicals production in the cell.
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28
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Hol FJH, Galajda P, Nagy K, Woolthuis RG, Dekker C, Keymer JE. Spatial structure facilitates cooperation in a social dilemma: empirical evidence from a bacterial community. PLoS One 2013; 8:e77042. [PMID: 24167557 PMCID: PMC3805552 DOI: 10.1371/journal.pone.0077042] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 09/06/2013] [Indexed: 11/25/2022] Open
Abstract
Cooperative organisms are ubiquitous in nature, despite their vulnerability to exploitation by cheaters. Although numerous theoretical studies suggest that spatial structure is critical for cooperation to persist, the spatial ecology of microbial cooperation remains largely unexplored experimentally. By tracking the community dynamics of cooperating (rpoS wild-type) and cheating (rpoS mutant) Escherichia coli in well-mixed flasks and microfabricated habitats, we demonstrate that spatial structure stabilizes coexistence between wild-type and mutant and thus facilitates cooperator maintenance. We develop a method to interpret our experimental results in the context of game theory, and show that the game wild-type and mutant bacteria play in an unstructured environment changes markedly over time, and eventually obeys a prisoner's dilemma leading to cheater dominance. In contrast, when wild-type and mutant E. coli co-inhabit a spatially-structured habitat, cooperators and cheaters coexist at intermediate frequencies. Our findings show that even in microhabitats lacking patchiness or spatial heterogeneities in resource availability, surface growth allows cells to form multi-cellular aggregates, yielding a self-structured community in which cooperators persist.
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Affiliation(s)
- Felix J. H. Hol
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Peter Galajda
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
- Institute of Biophysics, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
| | - Krisztina Nagy
- Institute of Biophysics, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
| | - Rutger G. Woolthuis
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Cees Dekker
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Juan E. Keymer
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
- Instituto de Ecología y Biodiversidad, Santiago, Chile
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29
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Lee HJ, Kim HJ, Seo J, Na YA, Lee J, Lee JY, Kim P. Estimation of phosphoenolpyruvate carboxylation mediated by phosphoenolpyruvate carboxykinase (PCK) in engineered Escherichia coli having high ATP. Enzyme Microb Technol 2013; 53:13-7. [PMID: 23683699 DOI: 10.1016/j.enzmictec.2013.04.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Revised: 03/29/2013] [Accepted: 04/01/2013] [Indexed: 01/09/2023]
Abstract
We have previously reported that phosphoenolpyruvate carboxykinase (PCK) overexpression under glycolytic conditions enables Escherichia coli to harbor a high intracellular ATP pool resulting in enhanced recombinant protein synthesis. To estimate how much PCK-mediated phosphoenolpyruvate (PEP) carboxylation is contributed to the ATP increase under engineered conditions, the kinetics of PEP carboxylation by PCK and substrate competing phosphoenolpyruvate carboxylase (PPC) were measured using recombinant enzymes. The PEP carboxylation catalytic efficiency (kcat/Km) of the recombinant PCK was 660mM(-1)min(-1), whereas that of the recombinant PPC was 1500mM(-1)min(-1). Under the presence of known allosteric effectors (fructose 1,6-bisphosphate, acetyl-CoA, ATP, malate, and aspartate) close to in vivo conditions, the catalytic efficiency of PCK-mediated PEP carboxylation (84mM(-1)min(-1)) was 28-folds lower than that of PPC (2370mM(-1)min(-1)). To verify the above results, an E. coli strain expressing native PCK and PPC under control of identical promoter was constructed by replacing PCK promoter region with that of PPC in chromosome. The native PCK activity (33nmol/mg-proteinmin) was 5-folds lower than PPC activity (160nmol/mg-proteinmin) in the cell extract from the promoter-exchanged strain. Intracellular modifications of ATP concentration by PCK activity and the consequences for biotechnology are further discussed.
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Affiliation(s)
- Hyo Jung Lee
- Department of Biotechnology, The Catholic University of Korea, Bucheon, Gyeonggi 420-743, Republic of Korea
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30
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Shimizu K. Metabolic Regulation of a Bacterial Cell System with Emphasis on Escherichia coli Metabolism. ISRN BIOCHEMISTRY 2013; 2013:645983. [PMID: 25937963 PMCID: PMC4393010 DOI: 10.1155/2013/645983] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Accepted: 10/25/2012] [Indexed: 12/19/2022]
Abstract
It is quite important to understand the overall metabolic regulation mechanism of bacterial cells such as Escherichia coli from both science (such as biochemistry) and engineering (such as metabolic engineering) points of view. Here, an attempt was made to clarify the overall metabolic regulation mechanism by focusing on the roles of global regulators which detect the culture or growth condition and manipulate a set of metabolic pathways by modulating the related gene expressions. For this, it was considered how the cell responds to a variety of culture environments such as carbon (catabolite regulation), nitrogen, and phosphate limitations, as well as the effects of oxygen level, pH (acid shock), temperature (heat shock), and nutrient starvation.
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Affiliation(s)
- Kazuyuki Shimizu
- Kyushu Institute of Technology, Fukuoka, Iizuka 820-8502, Japan
- Institute of Advanced Bioscience, Keio University, Yamagata, Tsuruoka 997-0017, Japan
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31
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Effect of acidic condition on the metabolic regulation of Escherichia coli and its phoB mutant. Arch Microbiol 2012; 195:161-71. [DOI: 10.1007/s00203-012-0861-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Revised: 12/05/2012] [Accepted: 12/06/2012] [Indexed: 10/27/2022]
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32
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Filipič J, Kraigher B, Tepuš B, Kokol V, Mandic-Mulec I. Effects of low-density static magnetic fields on the growth and activities of wastewater bacteria Escherichia coli and Pseudomonas putida. BIORESOURCE TECHNOLOGY 2012; 120:225-232. [PMID: 22820111 DOI: 10.1016/j.biortech.2012.06.023] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2012] [Revised: 06/04/2012] [Accepted: 06/06/2012] [Indexed: 06/01/2023]
Abstract
The aim of this study was to explore the influence of a moderate static magnetic field (SMF) of different densities on Escherichia coli and Pseudomonas putida that are commonly found in wastewater treatment plants. In line with literature reports that SMF increases the efficiency of wastewater treatment the findings of this study indicated that SMF negatively influenced the growth but positively influenced the enzymatic activities and ATP levels of the two model bacteria. The inhibitory effect of SMF on growth of E. coli and P. putida was most pronounced at their optimal growth temperature (37°C and 28°C respectively) and was reversible shortly after the SMF had been terminated. Finally, the results suggested that the induced energy metabolism reflected in higher dehydrogenase activities and ATP levels may be more important for survival, and adaptation to SMF induced stress than the increase in the expression of the rpoS gene.
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Affiliation(s)
- Jasmina Filipič
- Ptuj Municipal Service Corporation, Puhova ulica 10, SI-2250 Ptuj, Slovenia
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33
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Metabolic engineering of Escherichia coli for the production of 1-propanol. Metab Eng 2012; 14:477-86. [PMID: 22871504 DOI: 10.1016/j.ymben.2012.07.006] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2012] [Revised: 07/09/2012] [Accepted: 07/23/2012] [Indexed: 11/22/2022]
Abstract
An engineered Escherichia coli strain that produces 1-propanol under aerobic condition was developed based on an L-threonine-overproducing E. coli strain. First, a feedback resistant ilvA gene encoding threonine dehydratase was introduced and the competing metabolic pathway genes were deleted. Further engineering was performed by overexpressing the cimA gene encoding citramalate synthase and the ackA gene encoding acetate kinase A/propionate kinase II, introducing a modified adhE gene encoding an aerobically functional AdhE, and by deleting the rpoS gene encoding the stationary phase sigma factor. Fed-batch culture of the final engineered strain harboring pBRthrABC-tac-cimA-tac-ackA and pTacDA-tac-adhE(mut) allowed production of 10.8 g L(-1) of 1-propanol with the yield and productivity of 0.107 g g(-1) and 0.144 g L(-1) h(-1), respectively, from 100 g L(-1) of glucose, and 10.3 g L(-1) of 1-propanol with the yield and productivity of 0.259 g g(-1) and 0.083 g L(-1) h(-1), respectively, from 40 g L(-1) glycerol.
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34
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Double-Strand Break Repair and Holliday Junction Processing Are Required for Chromosome Processing in Stationary-Phase Escherichia coli Cells. G3-GENES GENOMES GENETICS 2012; 1:417-26. [PMID: 22384352 PMCID: PMC3276156 DOI: 10.1534/g3.111.001057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/18/2011] [Accepted: 09/10/2011] [Indexed: 11/25/2022]
Abstract
As nutrients are depleted and cell division ceases in batch cultures of bacteria, active processes are required to ensure that each cell has a complete copy of its genome. How chromosome number is manipulated and maintained in nondividing bacterial cells is not fully understood. Using flow cytometric analysis of cells from different growth phases, we show that the Holliday junction–processing enzymes RuvABC and RecG, as well as RecBCD, the enzyme complex that initiates DNA double-strand break repair, are required to establish the normal distribution of fluorescent peaks, which is commonly accepted to reflect the distribution of chromosome numbers. Our results reveal that these proteins are required for the proper processing of chromosomes in stationary phase.
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35
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Vidovic S, Mangalappalli-Illathu AK, Xiong H, Korber DR. Heat acclimation and the role of RpoS in prolonged heat shock of Escherichia coli O157. Food Microbiol 2012; 30:457-64. [PMID: 22365361 DOI: 10.1016/j.fm.2011.12.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Revised: 12/11/2011] [Accepted: 12/28/2011] [Indexed: 11/29/2022]
Abstract
Escherichia coli, a commensal mesophile that primarily inhabits the gastro-intestinal tract, responds to temperature up-shifts with transient expression of stress-response proteins. The goal of this study was to identify adaptive proteins of E. coli O157 crucial for growth resumption of this human pathogen after heat shock, with specific focus on the role of the RpoS sigma factor. Using the comparative proteomic analysis of hyper-thermally acclimatized wild-type strain B-1 and rpoS-mutant strain SV521, we identified 39 proteins that underwent significantly-different induction upon temperature shock at 45°C or rpoS mutation. All identified proteins of the heat post-acclimation stimulon fell into two large sub-groups: (i) stress proteins, including molecular chaperons, proteases, DNA/RNA stabilizing enzymes, and anti-oxidant proteins, and (ii) housekeeping proteins. It was found that in the heat stress stimulon RpoS has significantly (P=0.012) limited control over the key stress proteins involved in translation, translational elongation, protein folding and refolding. However, RpoS showed a significant (P=0.035) control over the cellular metabolic processes that included NADPH regeneration, pentose-phosphate shunt, nicotinamide nucleotide and NADP metabolic processes, reflecting its specific importance in promoting resource utilization (energy, protein synthesis etc.) during proliferation of hyperthermally-adapted cells. Pathogenic strains, like E. coli O157, have the ability to survive a variety of harsh stress conditions, leading to their entry into the food chain, and subsequent pathogenesis. This research offers insights into the physiological response of this pathogen during the critical period following adaptation to thermal stress and subsequent resumption of growth.
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Affiliation(s)
- Sinisa Vidovic
- Department of Food and Bioproducts Sciences, University of Saskatchewan, Saskatoon SK S7N 5A8, Canada
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36
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Global transcriptome analysis of the E. coli O157 response to Agrimonia pilosa extract. Mol Cell Toxicol 2011. [DOI: 10.1007/s13273-011-0036-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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37
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Jin Y, Huang JD. Engineering a portable riboswitch-LacP hybrid device for two-way gene regulation. Nucleic Acids Res 2011; 39:e131. [PMID: 21803790 PMCID: PMC3201887 DOI: 10.1093/nar/gkr609] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Riboswitches are RNA-based regulatory devices that mediate ligand-dependent control of gene expression. However, there has been limited success in rationally designing riboswitches. Moreover, most previous riboswitches are confined to a particular gene and only perform one-way regulation. Here, we used a library screening strategy for efficient creation of ON and OFF riboswitches of lacI on the chromosome of Escherichia coli. We then engineered a riboswitch-LacP hybrid device to achieve portable gene control in response to theophylline and IPTG. Moreover, this device regulated target expression in a ‘two-way’ manner: the default state of target expression was ON; the expression was switched off by adding theophylline and restored to the ON state by adding IPTG without changing growth medium. We showcased the portability and two-way regulation of this device by applying it to the small RNA CsrB and the RpoS protein. Finally, the use of the hybrid device uncovered an inhibitory role of RpoS in acetate assimilation, a function which is otherwise neglected using conventional genetic approaches. Overall, this work establishes a portable riboswitch-LacP device that achieves sequential OFF-and-ON gene regulation. The two-way control of gene expression has various potential scientific and biotechnological applications and helps reveal novel gene functions.
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Affiliation(s)
- Ye Jin
- Department of Biochemistry, Li Ka Shing Faculty of Medicine, University of Hong Kong, Pok Fu Lam, Hong Kong SAR, People's Republic of China
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38
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Peng S, Tasara T, Hummerjohann J, Stephan R. An overview of molecular stress response mechanisms in Escherichia coli contributing to survival of Shiga toxin-producing Escherichia coli during raw milk cheese production. J Food Prot 2011; 74:849-64. [PMID: 21549061 DOI: 10.4315/0362-028x.jfp-10-469] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The ability of foodborne pathogens to survive in certain foods mainly depends on stress response mechanisms. Insight into molecular properties enabling pathogenic bacteria to survive in food is valuable for improvement of the control of pathogens during food processing. Raw milk cheeses are a potential source for human infections with Shiga toxin-producing Escherichia coli (STEC). In this review, we focused on the stress response mechanisms important for allowing STEC to survive raw milk cheese production processes. The major components and regulation pathways for general, acid, osmotic, and heat shock stress responses in E. coli and the implications of these responses for the survival of STEC in raw milk cheeses are discussed.
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Affiliation(s)
- Silvio Peng
- Institute for Food Safety and Hygiene, University of Zurich, Winterthurerstrasse 272, 8057 Zürich, Switzerland
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39
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Levert M, Zamfir O, Clermont O, Bouvet O, Lespinats S, Hipeaux MC, Branger C, Picard B, Saint-Ruf C, Norel F, Balliau T, Zivy M, Le Nagard H, Cruvellier S, Chane-Woon-Ming B, Nilsson S, Gudelj I, Phan K, Ferenci T, Tenaillon O, Denamur E. Molecular and evolutionary bases of within-patient genotypic and phenotypic diversity in Escherichia coli extraintestinal infections. PLoS Pathog 2010; 6:e1001125. [PMID: 20941353 PMCID: PMC2947995 DOI: 10.1371/journal.ppat.1001125] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2010] [Accepted: 08/31/2010] [Indexed: 12/22/2022] Open
Abstract
Although polymicrobial infections, caused by combinations of viruses, bacteria, fungi and parasites, are being recognised with increasing frequency, little is known about the occurrence of within-species diversity in bacterial infections and the molecular and evolutionary bases of this diversity. We used multiple approaches to study the genomic and phenotypic diversity among 226 Escherichia coli isolates from deep and closed visceral infections occurring in 19 patients. We observed genomic variability among isolates from the same site within 11 patients. This diversity was of two types, as patients were infected either by several distinct E. coli clones (4 patients) or by members of a single clone that exhibit micro-heterogeneity (11 patients); both types of diversity were present in 4 patients. A surprisingly wide continuum of antibiotic resistance, outer membrane permeability, growth rate, stress resistance, red dry and rough morphotype characteristics and virulence properties were present within the isolates of single clones in 8 of the 11 patients showing genomic micro-heterogeneity. Many of the observed phenotypic differences within clones affected the trade-off between self-preservation and nutritional competence (SPANC). We showed in 3 patients that this phenotypic variability was associated with distinct levels of RpoS in co-existing isolates. Genome mutational analysis and global proteomic comparisons in isolates from a patient revealed a star-like relationship of changes amongst clonally diverging isolates. A mathematical model demonstrated that multiple genotypes with distinct RpoS levels can co-exist as a result of the SPANC trade-off. In the cases involving infection by a single clone, we present several lines of evidence to suggest diversification during the infectious process rather than an infection by multiple isolates exhibiting a micro-heterogeneity. Our results suggest that bacteria are subject to trade-offs during an infectious process and that the observed diversity resembled results obtained in experimental evolution studies. Whatever the mechanisms leading to diversity, our results have strong medical implications in terms of the need for more extensive isolate testing before deciding on antibiotic therapies. We investigated whether an infection is a site of pathogen within-species diversity. Our results indicate that there is indeed extensive diversity during human extraintestinal infections by Escherichia coli. This diversity was of two types, not mutually exclusive, as we found that patients were infected either by several distinct E. coli clones or by members of a single clone that exhibit micro-heterogeneity. The high degree of phenotypic diversity, including antibiotic resistance, suggests that there is no uniform selection pressure leading to a single fitter clone during an infection. We discuss a possible mechanism and a mathematical model that explains these unexpected results. Our data suggest that the evolution of diversity in the course of an infection and in in vitro experimental evolution in the absence of host immune selective pressure may have many parallels. Whatever the mechanisms leading to diversity, our results have strong medical implications in terms of the need for more extensive isolate testing before deciding on antibiotic therapies.
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Affiliation(s)
- Maxime Levert
- INSERM U722 and Université Paris 7 Denis Diderot, Faculté de Médecine, Site Xavier Bichat, Paris, France
| | - Oana Zamfir
- INSERM U722 and Université Paris 7 Denis Diderot, Faculté de Médecine, Site Xavier Bichat, Paris, France
| | - Olivier Clermont
- INSERM U722 and Université Paris 7 Denis Diderot, Faculté de Médecine, Site Xavier Bichat, Paris, France
| | - Odile Bouvet
- INSERM U722 and Université Paris 7 Denis Diderot, Faculté de Médecine, Site Xavier Bichat, Paris, France
| | - Sylvain Lespinats
- INSERM U722 and Université Paris 7 Denis Diderot, Faculté de Médecine, Site Xavier Bichat, Paris, France
| | - Marie Claire Hipeaux
- Assistance Publique - Hôpitaux de Paris, Hôpital Louis Mourier, Laboratoire de Microbiologie, Colombes, France
| | - Catherine Branger
- INSERM U722 and Université Paris 7 Denis Diderot, Faculté de Médecine, Site Xavier Bichat, Paris, France
- Assistance Publique - Hôpitaux de Paris, Hôpital Louis Mourier, Laboratoire de Microbiologie, Colombes, France
| | - Bertrand Picard
- INSERM U722 and Université Paris 7 Denis Diderot, Faculté de Médecine, Site Xavier Bichat, Paris, France
| | - Claude Saint-Ruf
- INSERM U1001 and Université Paris 5 René Descartes, Faculté de Médecine, Paris, France
| | - Françoise Norel
- Unité de Génétique Moléculaire and CNRS URA2172, Institut Pasteur, Paris, France
| | - Thierry Balliau
- CNRS UMR 0320/UMR8120 Génétique Végétale, Plate-Forme de Protéomique PAPPSO, Gif-sur-Yvette, France
| | - Michel Zivy
- CNRS UMR 0320/UMR8120 Génétique Végétale, Plate-Forme de Protéomique PAPPSO, Gif-sur-Yvette, France
| | - Hervé Le Nagard
- INSERM U738 and Université Paris 7 Denis Diderot, Faculté de Médecine, Site Xavier Bichat, Paris, France
| | - Stéphane Cruvellier
- Laboratoire de Génomique Comparative, CNRS UMR8030, Institut de Génomique, CEA, Genoscope, Evry, France
| | - Béatrice Chane-Woon-Ming
- Laboratoire de Génomique Comparative, CNRS UMR8030, Institut de Génomique, CEA, Genoscope, Evry, France
| | - Susanna Nilsson
- Department of Mathematics, Imperial College, London, United Kingdom
| | - Ivana Gudelj
- Department of Mathematics, Imperial College, London, United Kingdom
| | - Katherine Phan
- School of Molecular Bioscience, University of Sydney, Sydney, New South Wales, Australia
| | - Thomas Ferenci
- School of Molecular Bioscience, University of Sydney, Sydney, New South Wales, Australia
| | - Olivier Tenaillon
- INSERM U722 and Université Paris 7 Denis Diderot, Faculté de Médecine, Site Xavier Bichat, Paris, France
| | - Erick Denamur
- INSERM U722 and Université Paris 7 Denis Diderot, Faculté de Médecine, Site Xavier Bichat, Paris, France
- * E-mail:
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Timmermans J, Van Melderen L. Post-transcriptional global regulation by CsrA in bacteria. Cell Mol Life Sci 2010; 67:2897-908. [PMID: 20446015 PMCID: PMC11115721 DOI: 10.1007/s00018-010-0381-z] [Citation(s) in RCA: 138] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2010] [Revised: 04/14/2010] [Accepted: 04/20/2010] [Indexed: 12/16/2022]
Abstract
Global regulation allows bacteria to rapidly modulate the expression of a large variety of unrelated genes in response to environmental changes. Global regulators act at different levels of gene expression. This review focuses on CsrA, a post-transcriptional regulator that affects translation of its gene targets by binding mRNAs. CsrA controls a large variety of physiological processes such as central carbon metabolism, motility and biofilm formation. The activity of CsrA is itself tightly regulated by the CsrB and CsrC small RNAs and the BarA-UvrY two-component system.
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Affiliation(s)
- Johan Timmermans
- Laboratoire de Génétique et Physiologie Bactérienne, Institut de Biologie et de Médecine Moléculaires, Faculté des Sciences, Université Libre de Bruxelles, 12 rue des Professeurs Jeener et Brachet, 6041 Gosselies, Belgium
| | - Laurence Van Melderen
- Laboratoire de Génétique et Physiologie Bactérienne, Institut de Biologie et de Médecine Moléculaires, Faculté des Sciences, Université Libre de Bruxelles, 12 rue des Professeurs Jeener et Brachet, 6041 Gosselies, Belgium
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Arense P, Bernal V, Iborra JL, Cánovas M. Metabolic adaptation of Escherichia coli to long-term exposure to salt stress. Process Biochem 2010. [DOI: 10.1016/j.procbio.2010.05.022] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Tradeoff between enzyme and metabolite efficiency maintains metabolic homeostasis upon perturbations in enzyme capacity. Mol Syst Biol 2010; 6:356. [PMID: 20393576 PMCID: PMC2872607 DOI: 10.1038/msb.2010.11] [Citation(s) in RCA: 118] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2009] [Accepted: 02/09/2010] [Indexed: 11/29/2022] Open
Abstract
Substrate metabolite concentrations are inversely related to the in vivo capacity of their converting enzymes. Local metabolite responses represent a passive mechanism to achieve metabolic homeostasis upon perturbations in enzyme capacity. Enzyme capacity and metabolite concentration control the metabolic reaction rate.
Physiological behavior emerges from complex dynamic interactions between transcripts, enzymes, and metabolites, the constituents of metabolism, and its regulatory network (Sauer, 2006). Although large data sets can be generated on all these variables, data integration, in particular across different omics levels, is becoming the key challenge (Stitt and Fernie, 2003; Sauer et al, 2007). In this study, we identify a general relationship between substrates of an enzymatic reaction and enzymatic capacity in central carbon metabolism that allows the prediction of changes in metabolite concentration based on changes in enzyme capacity and vise versa. To elucidate whether general relationships exist between metabolite concentrations and enzyme capacities (i.e. the outcome of enzyme abundance combined with activity), we propose three hypothetical and alternative governing principles. The first hypothesis postulates a minimization of metabolite concentration at a given flux. In this case, no correlation between alterations in metabolite concentrations and enzyme capacities is expected. The second hypothesis postulates a tradeoff between metabolite concentration and enzyme capacity. In this case, a negative correlation between differences in concentrations of substrate metabolites and differences in enzyme capacity is expected. The third hypothesis postulates a minimization of enzyme capacity at a given flux. In this case, we expect a positive correlation between differences in concentrations of product metabolites and differences in enzyme capacity. As hypotheses I–III imply different relationships between enzyme capacities and metabolite concentrations, identification of the prevailing situation in microbial metabolism requires quantitative in vivo metabolite concentration and enzyme capacity data upon moderate changes in enzyme capacity. As a first test, we chose wild type Saccharomyces cerevisiae and an otherwise isogenic mutant with a complete deletion of the transcription factor Gcr2p, an activator of glycolysis (Chambers et al, 1995). This mutant exhibits altered transcript abundances, enzyme activities, and metabolite concentrations within closely connected reactions in glycolysis and in the tricarboxylic acid cycle (Uemura and Fraenkel, 1990, 1999; Sasaki and Uemura, 2005). To quantify the relationship between metabolite concentrations and enzyme capacities, we determined transcript, enzyme, and metabolite abundances in wild type and GCR2 mutant in batch culture on glucose minimal medium. Transcript and enzyme abundances are used as surrogates for enzyme capacities. The most significant correlation was observed for fold-changes in substrate metabolite concentrations with fold-changes in enzyme abundance. Not unexpectedly, enzyme abundances were a significantly better approximation for enzyme capacities than transcript abundances. A further improved correlation was achieved by considering all diverging enzymes that react upon a given substrate metabolite simultaneously rather than considering them as a separate reaction (Figure 4). The high correlation between substrate metabolite and enzyme fold-changes suggests a tradeoff between enzyme capacity and metabolite concentrations in central metabolism. To test the general validity for central carbon metabolism of the above-identified tradeoff between reaction substrate metabolite concentrations and enzyme abundances, we performed four independent validations: a statistical, a literature based, and two experimental ones. Statistically, we verified that the correlation between substrate metabolites and enzymes could not have been found by chance. On the basis of the literature data, we performed the above correlation analysis with literature data. All available data followed the proposed correlation, thus providing further evidence for the general validity of this relationship. As a more serious challenge of the identified correlation, we designed an experiment where the absolute flux alterations are large and additionally the flux directions are altered. We expected the substrate metabolites to occur at higher concentrations in the mutant than in the wild type. This expectation was fulfilled by the experimental data in all cases, thereby further corroborating the negative correlation between enzyme capacity and metabolite concentrations. So far, our experimental evidence was based on perturbing multiple enzyme abundances through a transcription factor mutant. To ensure that our findings are also valid for single-reaction perturbations, we modulated individual abundances of the four glycolytic enzymes Pgi1p, Tpi1p, Eno2p, and Cdc19p using strains whose endogenous genomic promotor was replaced by a Tet-controlled promotor (Mnaimneh et al, 2004) (Figure 7). Thus, we determined intracellular metabolites concentrations during exponential growth in the strains with modulated enzyme abundance. Our above-identified correlation predicts metabolite concentrations to increase only for the substrate of the such perturbed reaction and all other metabolite concentrations to remain constant. This prediction was verified. We demonstrate here that global or local alterations in enzyme abundance correlate negatively with enzyme reaction substrate concentration at least in central carbon metabolism. This implies a tradeoff between enzyme and metabolite efficiency in metabolic networks. These findings can be interpreted as a passive network mechanism to maintain close-to-wild-type homeostasis of central carbon metabolism upon perturbations that alter the enzyme capacity. The alterations are compensated by converse changes in reaction substrate concentrations, thereby minimizing the difference in metabolic flux that is caused by the alteration. What is the relationship between enzymes and metabolites, the two major constituents of metabolic networks? We propose three alternative relationships between enzyme capacity and metabolite concentration alterations based on a Michaelis–Menten kinetic; that is enzyme capacities, metabolite concentrations, or both could limit the metabolic reaction rates. These relationships imply different correlations between changes in enzyme capacity and metabolite concentration, which we tested by quantifying metabolite, transcript, and enzyme abundances upon local (single-enzyme modulation) and global (GCR2 transcription factor mutant) perturbations in Saccharomyces cerevisiae. Our results reveal an inverse relationship between fold-changes in substrate metabolites and their catalyzing enzymes. These data provide evidence for the hypothesis that reaction rates are jointly limited by enzyme capacity and metabolite concentration. Hence, alteration in one network constituent can be efficiently buffered by converse alterations in the other constituent, implying a passive mechanism to maintain metabolic homeostasis upon perturbations in enzyme capacity.
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Metabolic regulation of Escherichia coli and its glnG and zwf mutants under nitrogen limitation. Biochem Eng J 2010. [DOI: 10.1016/j.bej.2009.10.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Abstract
Understanding mechanisms of bacterial pathogenesis is critical for infectious disease control and treatment. Infection is a sophisticated process that requires the participation of global regulators to coordinate expression of not only genes coding for virulence factors but also those involved in other physiological processes, such as stress response and metabolic flux, to adapt to host environments. RpoS is a key response regulator to stress conditions in Escherichia coli and many other proteobacteria. In contrast to its conserved well-understood role in stress response, effects of RpoS on pathogenesis are highly variable and dependent on species. RpoS contributes to virulence through either enhancing survival against host defense systems or directly regulating expression of virulence factors in some pathogens, while RpoS is dispensable, or even inhibitory, to virulence in others. In this review, we focus on the distinct and niche-dependent role of RpoS in virulence by surveying recent findings in many pathogens.
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Kinnersley MA, Holben WE, Rosenzweig F. E Unibus Plurum: genomic analysis of an experimentally evolved polymorphism in Escherichia coli. PLoS Genet 2009; 5:e1000713. [PMID: 19893610 PMCID: PMC2763269 DOI: 10.1371/journal.pgen.1000713] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2009] [Accepted: 10/06/2009] [Indexed: 12/02/2022] Open
Abstract
Microbial populations founded by a single clone and propagated under resource limitation can become polymorphic. We sought to elucidate genetic mechanisms whereby a polymorphism evolved in Escherichia coli under glucose limitation and persisted because of cross-feeding among multiple adaptive clones. Apart from a 29 kb deletion in the dominant clone, no large-scale genomic changes distinguished evolved clones from their common ancestor. Using transcriptional profiling on co-evolved clones cultured separately under glucose-limitation we identified 180 genes significantly altered in expression relative to the common ancestor grown under similar conditions. Ninety of these were similarly expressed in all clones, and many of the genes affected (e.g., mglBAC, mglD, and lamB) are in operons coordinately regulated by CRP and/or rpoS. While the remaining significant expression differences were clone-specific, 93% were exhibited by the majority clone, many of which are controlled by global regulators, CRP and CpxR. When transcriptional profiling was performed on adaptive clones cultured together, many expression differences that distinguished the majority clone cultured in isolation were absent, suggesting that CpxR may be activated by overflow metabolites removed by cross-feeding strains in co-culture. Relative to their common ancestor, shared expression differences among adaptive clones were partly attributable to early-arising shared mutations in the trans-acting global regulator, rpoS, and the cis-acting regulator, mglO. Gene expression differences that distinguished clones may in part be explained by mutations in trans-acting regulators malT and glpK, and in cis-acting sequences of acs. In the founder, a cis-regulatory mutation in acs (acetyl CoA synthetase) and a structural mutation in glpR (glycerol-3-phosphate repressor) likely favored evolution of specialists that thrive on overflow metabolites. Later-arising mutations that led to specialization emphasize the importance of compensatory rather than gain-of-function mutations in this system. Taken together, these findings underscore the importance of regulatory change, founder genotype, and the biotic environment in the adaptive evolution of microbes. Experimental evolution of asexual species has shown that multiple genotypes can arise from a single ancestor and stably coexist (e unibus plurum). Although facilitated by environmental heterogeneity, this phenomenon also occurs in simple, homogeneous environments provisioned with a single limiting nutrient. We sought to discover genetic mechanisms that enabled an E. coli population founded by a single clone to become an interacting community composed of multiple clones. The founder of this population contained mutations that impair regulation of acetate and glycerol metabolism and likely favored the evolution of cross-feeding. Adaptive clones share cis- and trans-regulatory mutations shown elsewhere to enhance fitness under glucose limitation. Certain mutations that distinguish adaptive clones and underlie evolution of specialists were compensatory rather than gain-of-function, and all that we detected resulted in gene expression changes rather than protein structure changes. Evolved clones exhibited both common and clone-specific gene expression changes relative to their common ancestor; the pattern of gene expression in the dominant clone cultured alone differed from the pattern observed when it was cultured with variants feeding on its overflow metabolites. These findings illuminate the roles played by founder genotype, differential gene regulation, and the biotic environment in the adaptive evolution of bacteria.
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Affiliation(s)
- Margie A. Kinnersley
- Division of Biological Sciences, University of Montana, Missoula, Montana, United States of America
| | - William E. Holben
- Division of Biological Sciences, University of Montana, Missoula, Montana, United States of America
| | - Frank Rosenzweig
- Division of Biological Sciences, University of Montana, Missoula, Montana, United States of America
- * E-mail:
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Toward systematic metabolic engineering based on the analysis of metabolic regulation by the integration of different levels of information. Biochem Eng J 2009. [DOI: 10.1016/j.bej.2009.06.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Castaño-Cerezo S, Pastor JM, Renilla S, Bernal V, Iborra JL, Cánovas M. An insight into the role of phosphotransacetylase (pta) and the acetate/acetyl-CoA node in Escherichia coli. Microb Cell Fact 2009; 8:54. [PMID: 19852855 PMCID: PMC2774668 DOI: 10.1186/1475-2859-8-54] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2009] [Accepted: 10/24/2009] [Indexed: 06/29/2024] Open
Abstract
Background Acetate metabolism in Escherichia coli plays an important role in the control of the central metabolism and in bioprocess performance. The main problems related to the use of E. coli as cellular factory are i) the deficient utilization of carbon source due to the excretion of acetate during aerobic growth, ii) the inhibition of cellular growth and protein production by acetate and iii) the need for cofactor recycling (namely redox coenzymes and free CoASH) to sustain balanced growth and cellular homeostasis. Results This work analyzes the effect of mutations in the acetate excretion/assimilation pathways, acetyl-CoA synthethase (acs) and phosphotransacetylase (pta), in E. coli BW25113 grown on glucose or acetate minimal media. Biomass and metabolite production, redox (NADH/NAD+) and energy (ATP) state, enzyme activities and gene expression profiles related to the central metabolism were analyzed. The knock-out of pta led to a more altered phenotype than that of acs. Deletion of pta reduced the ability to grow on acetate as carbon source and strongly affected the expression of several genes related to central metabolic pathways. Conclusion Results showed that pta limits biomass yield in aerobic glucose cultures, due to acetate production (overflow metabolism) and its inefficient use during glucose starvation. Deletion of pta severely impaired growth on acetate minimal medium and under anaerobiosis due to decreased acetyl-coenzyme A synthethase, glyoxylate shunt and gluconeogenic activities, leading to lower growth rate. When acetate is used as carbon source, the joint expression of pta and acs is crucial for growth and substrate assimilation, while pta deletion severely impaired anaerobic growth. Finally, at an adaptive level, pta deficiency makes the strain more sensitive to environmental changes and de-regulates the central metabolism.
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Affiliation(s)
- Sara Castaño-Cerezo
- Department of Biochemistry and Molecular Biology B and Immunology, Campus de Espinardo, Universidad de Murcia, E-30100, Spain.
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Olvera L, Mendoza-Vargas A, Flores N, Olvera M, Sigala JC, Gosset G, Morett E, Bolívar F. Transcription analysis of central metabolism genes in Escherichia coli. Possible roles of sigma38 in their expression, as a response to carbon limitation. PLoS One 2009; 4:e7466. [PMID: 19838295 PMCID: PMC2759082 DOI: 10.1371/journal.pone.0007466] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2009] [Accepted: 09/18/2009] [Indexed: 11/29/2022] Open
Abstract
The phosphoenolpyruvate: carbohydrate transferase system (PTS) transports glucose in Escherichia coli. Previous work demonstrated that strains lacking PTS, such as PB11, grow slow on glucose. PB11 has a reduced expression of glycolytic, and upregulates poxB and acs genes as compared to the parental strain JM101, when growing on glucose. The products of the latter genes are involved in the production of AcetylCoA. Inactivation of rpoS that codes for the RNA polymerase σ38 subunit, reduces further (50%) growth of PB11, indicating that σ38 plays a central role in the expression of central metabolism genes in slowly growing cells. In fact, transcription levels of glycolytic genes is reduced in strain PB11rpoS− as compared to PB11. In this report we studied the role of σ70 and σ38 in the expression of the complete glycolytic pathway and poxB and acs genes in certain PTS− strains and their rpoS− derivatives. We determined the transcription start sites (TSSs) and the corresponding promoters, in strains JM101, PB11, its derivative PB12 that recovered its growth capacity, and in their rpoS− derivatives, by 5′RACE and pyrosequencing. In all these genes the presence of sequences resembling σ38 recognition sites allowed the proposition that they could be transcribed by both sigma factors, from overlapping putative promoters that initiate transcription at the same site. Fourteen new TSSs were identified in seventeen genes. Besides, more than 30 putative promoters were proposed and we confirmed ten previously reported. In vitro transcription experiments support the functionality of putative dual promoters. Alternatives that could also explain lower transcription levels of the rpoS− derivatives are discussed. We propose that the presence if real, of both σ70 and σ38 dependent promoters in all glycolytic genes and operons could allow a differential transcription of these central metabolism genes by both sigma subunits as an adaptation response to carbon limitation.
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Affiliation(s)
- Leticia Olvera
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología. Universidad Nacional Autónoma de México (UNAM), Cuernavaca Morelos, México
| | - Alfredo Mendoza-Vargas
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología. Universidad Nacional Autónoma de México (UNAM), Cuernavaca Morelos, México
| | - Noemí Flores
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología. Universidad Nacional Autónoma de México (UNAM), Cuernavaca Morelos, México
| | - Maricela Olvera
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología. Universidad Nacional Autónoma de México (UNAM), Cuernavaca Morelos, México
| | - Juan Carlos Sigala
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología. Universidad Nacional Autónoma de México (UNAM), Cuernavaca Morelos, México
| | - Guillermo Gosset
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología. Universidad Nacional Autónoma de México (UNAM), Cuernavaca Morelos, México
| | - Enrique Morett
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología. Universidad Nacional Autónoma de México (UNAM), Cuernavaca Morelos, México
- * E-mail: (EM); (FB)
| | - Francisco Bolívar
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología. Universidad Nacional Autónoma de México (UNAM), Cuernavaca Morelos, México
- * E-mail: (EM); (FB)
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Abo-Amer AE, Altalhi AD. RpoS-independent and growth phase-dependent expression of dcuSR operon of Escherichia coli. Acta Microbiol Immunol Hung 2009; 56:211-27. [PMID: 19789137 DOI: 10.1556/amicr.56.2009.3.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The dcuSR operon of Escherichia coli encodes a two-component sensor/kinase-response/regulator system. This system regulates gene expression in response to external C 4 -dicarboxylates. During entry into stationary phase Gram-negative bacteria express genes that impart cellular resistance to environmental stresses. In E. coli , 50 or more genes are triggered by sigma factor ( sigma s ) during entry into stationary phase. Multi-copy dcuS-lacZ and chromosomally integrated dcuS-lacZ fusions analysis showed that the expression of dcuSR is positively regulated during growth phase. Many genes that are required for stationary-phase adaptation are controlled by RpoS, a conserved alternative sigma factor, whose expression is, in turn, controlled by many factors. To understand whether the dcuSR is dependent upon RpoS, a RpoS- dcuS-lacZ strain was generated. beta -Galactosidase assay and Western blot analysis reported that the generated RpoS- dcuS-lacZ strain and the wild type showed the same expression during stationary phase. Surprisingly, the growth phase-dependence of the expression of dcuSR is still present in RpoS- dcuS-lacZ strain suggesting that other growth-phase-dependent regulatory mechanisms (might be the DcuSR system or cAMP/CRP), in addition to RpoS, may control post-exponential dcuSR expression.
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Affiliation(s)
- A E Abo-Amer
- University of Taif Department of Biology, Faculty of Science Taif Saudi Arabia Kingdom.
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The fitness cost of streptomycin resistance depends on rpsL mutation, carbon source and RpoS (sigmaS). Genetics 2009; 183:539-46, 1SI-2SI. [PMID: 19652179 DOI: 10.1534/genetics.109.106104] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Mutations that cause antibiotic resistance often produce associated fitness costs. These costs have a detrimental effect on the fate of resistant organisms in natural populations and could be exploited in designing drugs, therapeutic regimes, and intervention strategies. The streptomycin resistance (StrR) mutations K42N and P90S in ribosomal protein S12 impair growth on rich medium. Surprisingly, in media with poorer carbon sources, the same StrR mutants grow faster than wild type. This improvement reflects a failure of these StrR mutants to induce the stress-inducible sigma factor RpoS (sigmaS), a key regulator of many stationary-phase and stress-inducible genes. On poorer carbon sources, wild-type cells induce sigmaS, which retards growth. By not inducing sigmaS, StrR mutants escape this self-imposed inhibition. Consistent with this interpretation, the StrR mutant loses its advantage over wild type when both strains lack an RpoS (sigmaS) gene. Failure to induce sigmaS produced the following side effects: (1) impaired induction of several stress-inducible genes, (2) reduced tolerance to thermal stress, and (3) reduced translational fidelity. These results suggest that RpoS may contribute to long-term cell survival, while actually limiting short-term growth rate under restrictive growth conditions. Accordingly, the StrR mutant avoids short-term growth limitation but is sensitized to other stresses. These results highlight the importance of measuring fitness costs under multiple experimental conditions not only to acquire a more relevant estimate of fitness, but also to reveal novel physiological weaknesses exploitable for drug development.
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