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Theillet FX, Luchinat E. In-cell NMR: Why and how? PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2022; 132-133:1-112. [PMID: 36496255 DOI: 10.1016/j.pnmrs.2022.04.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 04/19/2022] [Accepted: 04/27/2022] [Indexed: 06/17/2023]
Abstract
NMR spectroscopy has been applied to cells and tissues analysis since its beginnings, as early as 1950. We have attempted to gather here in a didactic fashion the broad diversity of data and ideas that emerged from NMR investigations on living cells. Covering a large proportion of the periodic table, NMR spectroscopy permits scrutiny of a great variety of atomic nuclei in all living organisms non-invasively. It has thus provided quantitative information on cellular atoms and their chemical environment, dynamics, or interactions. We will show that NMR studies have generated valuable knowledge on a vast array of cellular molecules and events, from water, salts, metabolites, cell walls, proteins, nucleic acids, drugs and drug targets, to pH, redox equilibria and chemical reactions. The characterization of such a multitude of objects at the atomic scale has thus shaped our mental representation of cellular life at multiple levels, together with major techniques like mass-spectrometry or microscopies. NMR studies on cells has accompanied the developments of MRI and metabolomics, and various subfields have flourished, coined with appealing names: fluxomics, foodomics, MRI and MRS (i.e. imaging and localized spectroscopy of living tissues, respectively), whole-cell NMR, on-cell ligand-based NMR, systems NMR, cellular structural biology, in-cell NMR… All these have not grown separately, but rather by reinforcing each other like a braided trunk. Hence, we try here to provide an analytical account of a large ensemble of intricately linked approaches, whose integration has been and will be key to their success. We present extensive overviews, firstly on the various types of information provided by NMR in a cellular environment (the "why", oriented towards a broad readership), and secondly on the employed NMR techniques and setups (the "how", where we discuss the past, current and future methods). Each subsection is constructed as a historical anthology, showing how the intrinsic properties of NMR spectroscopy and its developments structured the accessible knowledge on cellular phenomena. Using this systematic approach, we sought i) to make this review accessible to the broadest audience and ii) to highlight some early techniques that may find renewed interest. Finally, we present a brief discussion on what may be potential and desirable developments in the context of integrative studies in biology.
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Affiliation(s)
- Francois-Xavier Theillet
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France.
| | - Enrico Luchinat
- Dipartimento di Scienze e Tecnologie Agro-Alimentari, Alma Mater Studiorum - Università di Bologna, Piazza Goidanich 60, 47521 Cesena, Italy; CERM - Magnetic Resonance Center, and Neurofarba Department, Università degli Studi di Firenze, 50019 Sesto Fiorentino, Italy
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2
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White N, Sadeeshkumar H, Sun A, Sudarsan N, Breaker RR. Na + riboswitches regulate genes for diverse physiological processes in bacteria. Nat Chem Biol 2022; 18:878-885. [PMID: 35879547 PMCID: PMC9337991 DOI: 10.1038/s41589-022-01086-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 06/10/2022] [Indexed: 01/31/2023]
Abstract
Organisms presumably have mechanisms to monitor and physiologically adapt to changes in cellular Na+ concentrations. Only a single bacterial protein has previously been demonstrated to selectively sense Na+ and regulate gene expression. Here we report a riboswitch class, previously called the 'DUF1646 motif', whose members selectively sense Na+ and regulate the expression of genes relevant to sodium biology. Many proteins encoded by Na+-riboswitch-regulated genes are annotated as metal ion transporters, whereas others are involved in mitigating osmotic stress or harnessing Na+ gradients for ATP production. Na+ riboswitches exhibit dissociation constants in the low mM range, and strongly reject all other alkali and alkaline earth ions. Likewise, only Na+ triggers riboswitch-mediated transcription and gene expression changes. These findings reveal that some bacteria use Na+ riboswitches to monitor, adjust and exploit Na+ concentrations and gradients, and in some instances collaborate with c-di-AMP riboswitches to coordinate gene expression during osmotic stress.
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Affiliation(s)
- Neil White
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
- Howard Hughes Medical Institute, Yale University, New Haven, CT, USA
| | - Harini Sadeeshkumar
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | - Anna Sun
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | | | - Ronald R Breaker
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA.
- Howard Hughes Medical Institute, Yale University, New Haven, CT, USA.
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA.
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Jin X, Zhou M, Chen S, Li D, Cao X, Liu B. Effects of pH alterations on stress- and aging-induced protein phase separation. Cell Mol Life Sci 2022; 79:380. [PMID: 35750966 PMCID: PMC9232405 DOI: 10.1007/s00018-022-04393-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 04/26/2022] [Accepted: 05/21/2022] [Indexed: 01/18/2023]
Abstract
Upon stress challenges, proteins/RNAs undergo liquid–liquid phase separation (LLPS) to fine-tune cell physiology and metabolism to help cells adapt to adverse environments. The formation of LLPS has been recently linked with intracellular pH, and maintaining proper intracellular pH homeostasis is known to be essential for the survival of organisms. However, organisms are constantly exposed to diverse stresses, which are accompanied by alterations in the intracellular pH. Aging processes and human diseases are also intimately linked with intracellular pH alterations. In this review, we summarize stress-, aging-, and cancer-associated pH changes together with the mechanisms by which cells regulate cytosolic pH homeostasis. How critical cell components undergo LLPS in response to pH alterations is also discussed, along with the functional roles of intracellular pH fluctuation in the regulation of LLPS. Further studies investigating the interplay of pH with other stressors in LLPS regulation and identifying protein responses to different pH levels will provide an in-depth understanding of the mechanisms underlying pH-driven LLPS in cell adaptation. Moreover, deciphering aging and disease-associated pH changes that influence LLPS condensate formation could lead to a deeper understanding of the functional roles of biomolecular condensates in aging and aging-related diseases.
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Affiliation(s)
- Xuejiao Jin
- State Key Laboratory of Subtropical Silviculture, School of Forestry and Biotechnology, Zhejiang A&F University, Lin'an, Hangzhou, 311300, China
| | - Min Zhou
- State Key Laboratory of Subtropical Silviculture, School of Forestry and Biotechnology, Zhejiang A&F University, Lin'an, Hangzhou, 311300, China
| | - Shuxin Chen
- State Key Laboratory of Subtropical Silviculture, School of Forestry and Biotechnology, Zhejiang A&F University, Lin'an, Hangzhou, 311300, China
| | - Danqi Li
- State Key Laboratory of Subtropical Silviculture, School of Forestry and Biotechnology, Zhejiang A&F University, Lin'an, Hangzhou, 311300, China
| | - Xiuling Cao
- State Key Laboratory of Subtropical Silviculture, School of Forestry and Biotechnology, Zhejiang A&F University, Lin'an, Hangzhou, 311300, China.
| | - Beidong Liu
- State Key Laboratory of Subtropical Silviculture, School of Forestry and Biotechnology, Zhejiang A&F University, Lin'an, Hangzhou, 311300, China. .,Department of Chemistry and Molecular Biology, University of Gothenburg, Medicinaregatan 9C, 413 90, Goteborg, Sweden. .,Center for Large-Scale Cell-Based Screening, Faculty of Science, University of Gothenburg, Medicinaregatan 9C, 413 90, Goteborg, Sweden.
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4
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Travers A, Muskhelishvili G. Chromosomal Organization and Regulation of Genetic Function in Escherichia coli Integrates the DNA Analog and Digital Information. EcoSal Plus 2020; 9:10.1128/ecosalplus.ESP-0016-2019. [PMID: 32056535 PMCID: PMC11168577 DOI: 10.1128/ecosalplus.esp-0016-2019] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Indexed: 12/22/2022]
Abstract
In this article, we summarize our current understanding of the bacterial genetic regulation brought about by decades of studies using the Escherichia coli model. It became increasingly evident that the cellular genetic regulation system is organizationally closed, and a major challenge is to describe its circular operation in quantitative terms. We argue that integration of the DNA analog information (i.e., the probability distribution of the thermodynamic stability of base steps) and digital information (i.e., the probability distribution of unique triplets) in the genome provides a key to understanding the organizational logic of genetic control. During bacterial growth and adaptation, this integration is mediated by changes of DNA supercoiling contingent on environmentally induced shifts in intracellular ionic strength and energy charge. More specifically, coupling of dynamic alterations of the local intrinsic helical repeat in the structurally heterogeneous DNA polymer with structural-compositional changes of RNA polymerase holoenzyme emerges as a fundamental organizational principle of the genetic regulation system. We present a model of genetic regulation integrating the genomic pattern of DNA thermodynamic stability with the gene order and function along the chromosomal OriC-Ter axis, which acts as a principal coordinate system organizing the regulatory interactions in the genome.
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Affiliation(s)
- Andrew Travers
- Department of Biochemistry, University of Cambridge, Cambridge, UK
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, UK
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Crane JM, Randall LL. The Sec System: Protein Export in Escherichia coli. EcoSal Plus 2017; 7:10.1128/ecosalplus.ESP-0002-2017. [PMID: 29165233 PMCID: PMC5807066 DOI: 10.1128/ecosalplus.esp-0002-2017] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Indexed: 11/20/2022]
Abstract
In Escherichia coli, proteins found in the periplasm or the outer membrane are exported from the cytoplasm by the general secretory, Sec, system before they acquire stably folded structure. This dynamic process involves intricate interactions among cytoplasmic and membrane proteins, both peripheral and integral, as well as lipids. In vivo, both ATP hydrolysis and proton motive force are required. Here, we review the Sec system from the inception of the field through early 2016, including biochemical, genetic, and structural data.
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Affiliation(s)
- Jennine M. Crane
- Department of Biochemistry, University of Missouri, Columbia, Missouri
| | - Linda L. Randall
- Department of Biochemistry, University of Missouri, Columbia, Missouri
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Dong X, Tian B, Dai S, Li T, Guo L, Tan Z, Jiao Z, Jin Q, Wang Y, Hua Y. Expression of PprI from Deinococcus radiodurans Improves Lactic Acid Production and Stress Tolerance in Lactococcus lactis. PLoS One 2015; 10:e0142918. [PMID: 26562776 PMCID: PMC4643010 DOI: 10.1371/journal.pone.0142918] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 10/28/2015] [Indexed: 11/23/2022] Open
Abstract
PprI is a general switch protein that regulates the expression of certain proteins involved in pathways of cellular resistance in the extremophilic bacterium Deinococcus radiodurans. In this study, we transformed pprI into Lactococcus lactis strain MG1363 using the lactococcal shuttle vector pMG36e and investigated its effects on the tolerance and lactic acid production of L. lactis while under stress. PprI was stably expressed in L. lactis as confirmed by western blot assays. L. lactis expressing PprI exhibited significantly improved resistance to oxidative stress and high osmotic pressure. This enhanced cellular tolerance to stressors might be due to the regulation of resistance-related genes (e.g., recA, recO, sodA, and nah) by pprI. Moreover, transformed L. lactis demonstrated increased lactic acid production, attributed to enhanced lactate dehydrogenase activity. These results suggest that pprI can improve the tolerance of L. lactis to environmental stresses, and this transformed bacterial strain is a promising candidate for industrial applications of lactic acid production.
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Affiliation(s)
- Xiangrong Dong
- Henan Provincial Key Laboratory of Ion Beam Bio-engineering, Zhengzhou University, Zhengzhou, 450052, China
| | - Bing Tian
- Key Laboratory for Nuclear-Agricultural Sciences of Chinese Ministry of Agriculture and Zhejiang Province, Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, 310029, China
| | - Shang Dai
- Key Laboratory for Nuclear-Agricultural Sciences of Chinese Ministry of Agriculture and Zhejiang Province, Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, 310029, China
| | - Tao Li
- Key Laboratory for Nuclear-Agricultural Sciences of Chinese Ministry of Agriculture and Zhejiang Province, Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, 310029, China
| | - Linna Guo
- Henan Provincial Key Laboratory of Ion Beam Bio-engineering, Zhengzhou University, Zhengzhou, 450052, China
| | - Zhongfang Tan
- Henan Provincial Key Laboratory of Ion Beam Bio-engineering, Zhengzhou University, Zhengzhou, 450052, China
| | - Zhen Jiao
- Henan Provincial Key Laboratory of Ion Beam Bio-engineering, Zhengzhou University, Zhengzhou, 450052, China
| | - Qingsheng Jin
- Institute of Crops and Utilization of Nuclear Technology, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China
| | - Yanping Wang
- Henan Provincial Key Laboratory of Ion Beam Bio-engineering, Zhengzhou University, Zhengzhou, 450052, China
- * E-mail: (YW); (YH)
| | - Yuejin Hua
- Key Laboratory for Nuclear-Agricultural Sciences of Chinese Ministry of Agriculture and Zhejiang Province, Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, 310029, China
- * E-mail: (YW); (YH)
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7
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Impact of salinity on the aerobic metabolism of phosphate-accumulating organisms. Appl Microbiol Biotechnol 2014; 99:3659-72. [DOI: 10.1007/s00253-014-6287-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Revised: 11/27/2014] [Accepted: 11/29/2014] [Indexed: 11/25/2022]
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Welles L, Lopez-Vazquez CM, Hooijmans CM, van Loosdrecht MCM, Brdjanovic D. Impact of salinity on the anaerobic metabolism of phosphate-accumulating organisms (PAO) and glycogen-accumulating organisms (GAO). Appl Microbiol Biotechnol 2014; 98:7609-22. [DOI: 10.1007/s00253-014-5778-4] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Revised: 04/12/2014] [Accepted: 04/16/2014] [Indexed: 10/25/2022]
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10
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The Na+ transport in gram-positive bacteria defect in the Mrp antiporter complex measured with 23Na nuclear magnetic resonance. Anal Biochem 2013; 445:80-6. [PMID: 24139955 DOI: 10.1016/j.ab.2013.10.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Revised: 10/02/2013] [Accepted: 10/04/2013] [Indexed: 11/20/2022]
Abstract
(23)Na nuclear magnetic resonance (NMR) has previously been used to monitor Na(+) translocation across membranes in gram-negative bacteria and in various other organelles and liposomes using a membrane-impermeable shift reagent to resolve the signals resulting from internal and external Na(+). In this work, the (23)Na NMR method was adapted for measurements of internal Na(+) concentration in the gram-positive bacterium Bacillus subtilis, with the aim of assessing the Na(+) translocation activity of the Mrp (multiple resistance and pH) antiporter complex, a member of the cation proton antiporter-3 (CPA-3) family. The sodium-sensitive growth phenotype observed in a B. subtilis strain with the gene encoding MrpA deleted could indeed be correlated to the inability of this strain to maintain a lower internal Na(+) concentration than an external one.
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11
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García-Contreras R, Vos P, Westerhoff HV, Boogerd FC. Why in vivo may not equal in vitro - new effectors revealed by measurement of enzymatic activities under the same in vivo-like assay conditions. FEBS J 2012; 279:4145-59. [PMID: 22978366 DOI: 10.1111/febs.12007] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Revised: 08/09/2012] [Accepted: 09/10/2012] [Indexed: 01/10/2023]
Abstract
Does the understanding of the dynamics of biochemical networks in vivo, in terms of the properties of their components determined in vitro, require the latter to be determined all under the same conditions? An in vivo-like assay medium for enzyme activity determination was designed based on the concentrations of the major ionic constituents of the Escherichia coli cytosol: K(+), Na(+), Mg(2+), phosphate, glutamate, sulfate and Cl(-). The maximum capacities (V(max)) of the extracted enzymes of two pathways were determined using both this in vivo-like assay medium and the assay medium specific for each enzyme. The enzyme activities differed between the two assay conditions. Most of the differences could be attributed to unsuspected, pleiotropic effects of K(+) and phosphate. K(+) activated some enzymes (aldolase, enolase and glutamate dehydrogenase) and inhibited others (phosphoglucose isomerase, phosphofructokinase, triosephosphate isomerase, glyceraldehyde 3-phosphate dehydrogenase, phosphoglycerate kinase, phosphoglycerate mutase), whereas phosphate inhibited all glycolytic enzymes and glutamine synthetase but only activated glutamine 2-oxoglutarate amidotransferase. Neither a high glutamate concentration, nor macromolecular crowding affected the glycolytic or nitrogen assimilation enzymes, other than through the product inhibition of glutamate dehydrogenase by glutamate. This strategy of assessing all pathway enzymes kinetically under the same conditions may be necessary to avoid inadvertent differences between in vivo and in vitro biochemistry. It may also serve to reveal otherwise unnoticed pleiotropic regulation, such as that demonstrated in the present study by K(+) and phosphate.
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Affiliation(s)
- Rodolfo García-Contreras
- Section of Molecular Cell Physiology, Netherlands Institute for Systems Biology, VU University Amsterdam, The Netherlands
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12
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Batista AP, Pereira MM. Sodium influence on energy transduction by complexes I from Escherichia coli and Paracoccus denitrificans. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1807:286-92. [PMID: 21172303 DOI: 10.1016/j.bbabio.2010.12.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2010] [Revised: 11/30/2010] [Accepted: 12/11/2010] [Indexed: 11/25/2022]
Abstract
The nature of the ions that are translocated by Escherichia coli and Paracoccus denitrificans complexes I was investigated. We observed that E. coli complex I was capable of proton translocation in the same direction to the established deltapsi, showing that in the tested conditions, the coupling ion is the H(+). Furthermore, Na(+) transport to the opposite direction was also observed, and, although Na(+) was not necessary for the catalytic or proton transport activities, its presence increased the latter. We also observed H(+) translocation by P. denitrificans complex I, but in this case, H(+) transport was not influenced by Na(+) and also Na(+) transport was not observed. We concluded that E. coli complex I has two energy coupling sites (one Na(+) independent and the other Na(+) dependent), as previously observed for Rhodothermus marinus complex I, whereas the coupling mechanism of P. denitrificans enzyme is completely Na(+) independent. This work thus shows that complex I energy transduction by proton pumping and Na(+)/H(+) antiporting is not exclusive of the R. marinus enzyme. Nevertheless, the Na(+)/H(+) antiport activity seems not to be a general property of complex I, which may be correlated with the metabolic characteristics of the organisms.
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Affiliation(s)
- Ana P Batista
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. de Republica EAN, 2780-157 Oeiras, Portugal
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van der Star WRL, Dijkema C, de Waard P, Picioreanu C, Strous M, van Loosdrecht MCM. An intracellular pH gradient in the anammox bacterium Kuenenia stuttgartiensis as evaluated by 31P NMR. Appl Microbiol Biotechnol 2009; 86:311-7. [PMID: 19862513 PMCID: PMC2822221 DOI: 10.1007/s00253-009-2309-9] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2009] [Revised: 10/12/2009] [Accepted: 10/13/2009] [Indexed: 12/03/2022]
Abstract
The cytoplasm of anaerobic ammonium oxidizing (anammox) bacteria consists of three compartments separated by membranes. It has been suggested that a proton motive force may be generated over the membrane of the innermost compartment, the “anammoxosome”. 31P nuclear magnetic resonance (NMR) spectroscopy was employed to investigate intracellular pH differences in the anammox bacterium Kuenenia stuttgartiensis. With in vivo NMR, spectra were recorded of active, highly concentrated suspensions of K. stuttgartiensis in a wide-bore NMR tube. At different external pH values, two stable and distinct phosphate peaks were apparent in the recorded spectra. These peaks were equivalent with pH values of 7.3 and 6.3 and suggested the presence of a proton motive force over an intracytoplasmic membrane in K. stuttgartiensis. This study provides for the second time—after discovery of acidocalcisome-like compartments in Agrobacterium tumefaciens—evidence for an intracytoplasmic pH gradient in a chemotrophic prokaryotic cell.
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Affiliation(s)
- Wouter R L van der Star
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands
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Lo CJ, Leake MC, Berry RM. Fluorescence measurement of intracellular sodium concentration in single Escherichia coli cells. Biophys J 2005; 90:357-65. [PMID: 16227503 PMCID: PMC1367033 DOI: 10.1529/biophysj.105.071332] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The energy-transducing cytoplasmic membrane of bacteria contains pumps and antiports maintaining the membrane potential and ion gradients. We have developed a method for rapid, single-cell measurement of the internal sodium concentration ([Na(+)](in)) in Escherichia coli using the sodium ion fluorescence indicator, Sodium Green. The bacterial flagellar motor is a molecular machine that couples the transmembrane flow of ions, either protons (H(+)) or sodium ions (Na(+)), to flagellar rotation. We used an E. coli strain containing a chimeric flagellar motor with H(+)- and Na(+)-driven components that functions as a sodium motor. Changing external sodium concentration ([Na(+)](ex)) in the range 1-85 mM resulted in changes in [Na(+)](in) between 5-14 mM, indicating a partial homeostasis of internal sodium concentration. There were significant intercell variations in the relationship between [Na(+)](in) and [Na(+)](ex), and the internal sodium concentration in cells not expressing chimeric flagellar motors was 2-3 times lower, indicating that the sodium flux through these motors is a significant fraction of the total sodium flux into the cell.
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Affiliation(s)
- Chien-Jung Lo
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, United Kingdom
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15
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Grandjean D, Fass S, Tozza D, Cavard J, Lahoussine V, Saby S, Guilloteau H, Block JC. Coliform culturability in over- versus undersaturated drinking waters. WATER RESEARCH 2005; 39:1878-86. [PMID: 15899286 DOI: 10.1016/j.watres.2005.03.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2004] [Revised: 02/25/2005] [Indexed: 05/02/2023]
Abstract
The culturability of Escherichia coli in undersaturated drinking water with respect to CaCO3 (corrosive water) or in oversaturated water (non-corrosive water) was tested in different reactors: glass flasks (batch, "non-reactive" wall); glass reactors (chemostat, "non-reactive" wall) versus a corroded cast iron Propella reactor (chemostat, "reactive" wall) and a 15-year-old distribution system pilot (chemostat, "reactive" wall with 1% corroded cast iron and 99% cement-lined cast iron). The E. coli in E. coli-spiked drinking water was not able to maintain its culturability and colonize the experimental systems. It appears from our results that the optimal pH for maintaining E. coli culturability was around 8.2 or higher. However, in reactors with a reactive wall (corroded cast iron), the decline in E. coli culturability was slower when the pH was adjusted to 7.9 or 7.7 (i.e. a reactor fed with corrosive water; pH<pHs) than in non-corrosive water (pH 8.64 or 8.24; pH>pHs). We tentatively deduce that corrosion products coming from chemical reactions driven by corrosive waters on the pipe wall improve E. coli culturability.
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Affiliation(s)
- D Grandjean
- LCPME, UMR 7564 CNRS-UHP, Faculté de Pharmacie, Pôle de l'Eau, 15 avenue du Charmois, 54500 Vandoeuvre-lès-Nancy, France
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16
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Delort AM, Gaudet G, Forano E. 23Na NMR study of Fibrobacter succinogenes S85: comparison of three chemical shift reagents and calculation of sodium concentration using ionophores. Anal Biochem 2002; 306:171-80. [PMID: 12123653 DOI: 10.1006/abio.2002.5685] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In order to measure intracellular sodium concentrations in resting cells of Fibrobacter succinogenes S85 by (23)Na NMR spectrometry, two methodological aspects were studied. First, three different shift reagents (Dy(PPP(i))(7-)(2), Tm(DOTP)(5-), and Dy(TTHA)(3-)) were tested for their ability to separate internal and external (23)Na NMR resonances. Their toxicity toward F. succinogenes cells was evaluated by in vivo(13)C NMR experiments. Tm(DOTP)(5-) was found to be the most efficient shift reagent while being nontoxic. Second, a new methodology was developed to calculate intracellular sodium concentration in F. succinogenes by using ionophores. This approach avoided the problem of intracellular volume measurement and that of sodium visibility determination.
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Affiliation(s)
- Anne-Marie Delort
- Laboratoire de Synthèse et Etude de Systèmes à Intérêt Biologique, UMR 6504 Université Blaise Pascal-CNRS, 63177 Aubière Cedex, France.
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Schwaab V, Matheron C, Delort AM, Gaudet G, Forano E. In vivo 23Na nuclear magnetic resonance study of maintenance of a sodium gradient in the ruminal bacterium Fibrobacter succinogenes S85. Appl Environ Microbiol 2001; 67:4390-2. [PMID: 11526055 PMCID: PMC93179 DOI: 10.1128/aem.67.9.4390-4392.2001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Sodium gradients (DeltapNa) were measured in resting cells of Fibrobacter succinogenes by in vivo 23Na nuclear magnetic resonance using Tm(DOTP)5- [thulium(III) 1,4,7,10-tetraazacyclododecane-N',N",N"'-tetramethylenephosphonate] as the shift reagent. This bacterium was able to maintain a DeltapNa of -55 to -40 mV for extracellular sodium concentrations ranging from 30 to 200 mM. Depletion of Na+ ions during the washing steps led to irreversible damage (modification of glucose metabolism and inability to maintain a sodium gradient).
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Affiliation(s)
- V Schwaab
- Laboratoire de Synthèse, Electrosynthèse et Etude de Systèmes à Intérêt Biologique, UMR 6504, Université Blaise Pascal-CNRS, 63177 Aubière cedex, France
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Abstract
Examination of microbial diversity in environments of increasing salt concentrations indicates that certain types of dissimilatory metabolism do not occur at the highest salinities. Examples are methanogenesis for H2 + CO2 or from acetate, dissimilatory sulfate reduction with oxidation of acetate, and autotrophic nitrification. Occurrence of the different metabolic types is correlated with the free-energy change associated with the dissimilatory reactions. Life at high salt concentrations is energetically expensive. Most bacteria and also the methanogenic Archaea produce high intracellular concentrations of organic osmotic solutes at a high energetic cost. All halophilic microorganisms expend large amounts of energy to maintain steep gradients of NA+ and K+ concentrations across their cytoplasmic membrane. The energetic cost of salt adaptation probably dictates what types of metabolism can support life at the highest salt concentrations. Use of KCl as an intracellular solute, while requiring far-reaching adaptations of the intracellular machinery, is energetically more favorable than production of organic-compatible solutes. This may explain why the anaerobic halophilic fermentative bacteria (order Haloanaerobiales) use this strategy and also why halophilic homoacetogenic bacteria that produce acetate from H2 + CO2 exist whereas methanogens that use the same substrates in a reaction with a similar free-energy yield do not.
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Affiliation(s)
- A Oren
- Division of Microbial and Molecular Ecology, Institute of Life Sciences, and the Moshe Shilo Minerva Center for Marine Biogeochemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel.
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19
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Abstract
The kdpFABC operon of Escherichia coli encodes the four protein subunits of the Kdp K+ transport system. Kdp is expressed when growth is limited by the availability of K+. Expression of Kdp is dependent on the products of the adjacent kdpDE operon, which encodes a pair of two-component regulators. Studies with kdp-lac fusions led to the suggestion that change in turgor pressure acts as the signal to express Kdp (L. A. Laimins, D. B. Rhoads, and W. Epstein, Proc. Natl. Acad. Sci. USA 78:464-468, 1981). More recently, effects of compatible solutes, among others, have been interpreted as inconsistent with the turgor model (H. Asha and J. Gowrishankar, J. Bacteriol. 175:4528-4537, 1993). We re-examined the effects of compatible solutes and of medium pH on expression of Kdp in studies in which growth rate was also measured. In all cases, Kdp expression correlated with the K+ concentration when growth began to slow. Making the reasonable but currently untestable assumptions that the reduction in growth rate by K+ limitation is due to a reduction in turgor and that addition of betaine does not increase turgor, we concluded that all of the data on Kdp expression are consistent with control by turgor pressure.
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Affiliation(s)
- R Malli
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois 60637, USA
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20
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Dover N, Higgins CF, Carmel O, Rimon A, Pinner E, Padan E. Na+-induced transcription of nhaA, which encodes an Na+/H+ antiporter in Escherichia coli, is positively regulated by nhaR and affected by hns. J Bacteriol 1996; 178:6508-17. [PMID: 8932307 PMCID: PMC178537 DOI: 10.1128/jb.178.22.6508-6517.1996] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
nhaA encodes an Na+/H+ antiporter in Escherichia coli which is essential for adaptation to high salinity and alkaline pH in the presence of Na+. We used Northern (RNA) analysis to measure directly the cellular levels of nhaA mRNA. NhaR belongs to the LysR family of regulatory proteins. Consistent with our previous data with an nhaA'-'lacZ fusion, NhaR was found to be a positive regulator and Na+ was found to be a specific inducer of nhaA transcription. In the nhaA'-'lacZ fusion, maximal induction was observed at alkaline pH. In contrast, in the nhaA+ strain both the level of nhaA expression and the induction ratio were lower at alkaline pH. This difference may be due to the activity of NhaA in the wild-type strain as NhaA efficiently excreted Na+ at alkaline pH and reduced the intracellular concentration of Na+, the signal for induction. We also showed that although the global regulator rpoS was not involved in nhaA regulation, the global regulator hns played a role. Thus, the expression of nhaA'-'lacZ was derepressed in strains bearing hns mutations and transformation with a low-copy-number plasmid carrying hns repressed expression and restored Na+ induction. The derepression in hns strains was nhaR independent. Most interestingly, multicopy nhaR, which in an hns+ background acted only as an Na+-dependent positive regulator, acted as a repressor in an hns strain in the absence of Na+ but was activated in the presence of the ion. Hence, an interplay between nhaR and hns in the regulation of nhaA was suggested.
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Affiliation(s)
- N Dover
- Division of Microbial and Molecular Ecology, Institute of Life Sciences, Hebrew University of Jerusalem, Israel
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21
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Harel-Bronstein M, Dibrov P, Olami Y, Pinner E, Schuldiner S, Padan E. MH1, a second-site revertant of an Escherichia coli mutant lacking Na+/H+ antiporters (delta nhaA delta nhaB), regains Na+ resistance and a capacity to excrete Na+ in a delta microH(+)-independent fashion. J Biol Chem 1995; 270:3816-22. [PMID: 7876124 DOI: 10.1074/jbc.270.8.3816] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The Escherichia coli mutant delta nhaA delta nhaB (EP432), which lacks the two specific Na+/H+ antiporter genes, is incapable of efficiently excreting Na+. Accordingly at low K+ (6 mM) medium, its intracellular Na+ concentration is only slightly lower (1.5-2x) than the extracellular concentration (50 mM), explaining the high sensitivity to Na+ (> or = 30 mM) of the mutant. This Na+ sensitivity is shown to be a powerful selection for spontaneous second-site suppressor mutations that allow growth on high Na+ (< or = 0.6 M) with a rate similar to that of the wild type. One such mutation, MH1, maps at 25.7 min on the E. coli chromosome. It confers Na+ but not Li+ resistance upon delta nhaA delta nhaB cells and exposes a Na(+)-excreting capacity, maintaining a Na+ gradient of about 8-10 (at 50 mM extracellular Na+), which is similar to that of the wild type. Although lower, Na+ excretion capacity is also observed in the delta nhaA delta nhaB mutant when grown in medium containing higher K+ (70 mM). This capacity is accompanied with a shift in the sensitivity of the mutant to higher Na+ concentrations (> or = 300 mM). Whereas Na+ excretion by a wild type carrying delta unc is uncoupler sensitive, that of MH1 delta unc is dependent on respiration in an uncoupler-insensitive fashion. It is concluded that under some conditions (high K+ in the medium or in MH1-like mutants), a primary pump driven by respiration is responsible for Na+ extrusion when the Na+/H+ antiporters are not active.
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Affiliation(s)
- M Harel-Bronstein
- Division of Microbial and Molecular Ecology, Hebrew University of Jerusalem, Israel
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22
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Peña A, Ramírez J, Rosas G, Calahorra M. Proton pumping and the internal pH of yeast cells, measured with pyranine introduced by electroporation. J Bacteriol 1995; 177:1017-22. [PMID: 7860582 PMCID: PMC176697 DOI: 10.1128/jb.177.4.1017-1022.1995] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The internal pH of yeast cells was determined by measuring the fluorescence changes of pyranine (8-hydroxy-1,3,6-pyrene-trisulfonic acid), which was introduced into the cells by electroporation. This may be a suitable procedure for the following reasons. (i) Only minor changes in the physiological status of the cells seemed to be produced. (ii) The dye did not seem to leak at a significant rate from the cells. (iii) Different incubation conditions produced large fluorescence changes in the dye, which in general agree with present knowledge of the proton movements of the yeast cell under different conditions. (iv) Pyranine introduced by electroporation seemed to be located in the cytoplasm and to avoid the vacuole, and therefore it probably measured actual cytoplasmic pH. (v) Correction factors to obtain a more precise estimation of the internal pH are not difficult to apply, and the procedure may be useful for other yeasts and microorganisms, as well as for the introduction of other substances into cells. Values for the cytoplasmic pHs of yeast cells that were higher than those reported previously were obtained, probably because this fluorescent indicator did not seem to penetrate into the cell vacuole.
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Affiliation(s)
- A Peña
- Departmento de Microbiología, Universidad Nacional Autónoma de México, D. F., México
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23
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Na+ as coupling ion in energy transduction in extremophilic Bacteria and Archaea. World J Microbiol Biotechnol 1995; 11:58-70. [DOI: 10.1007/bf00339136] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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24
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Smirnova G, Oktyabrsky O. Betaine modulates intracellular thiol and potassium levels in Escherichia coli in medium with high osmolarity and alkaline pH. Arch Microbiol 1995; 163:76-8. [PMID: 7710325 DOI: 10.1007/bf00262207] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Glycine betaine stimulates the growth rate of various bacteria in high osmolarity medium. In our studies, glycine betaine stimulated the growth rate of Escherichia coli K12 in minimal medium with normal osmolarity at alkaline pH (pH 8.2). Betaine also caused a reduction in the intracellular pools of K+ and low molecular weight thiols in E. coli growing both in medium with high osmolarity and at alkaline pH. These effects of betaine were absent at pH 7.0. In cells growing in high osmolarity medium, 10 mM sodium acetate or 10 microM N-ethylmaleimide reduced expression of the osmosensitive gene proU to the same extent as treatment with betaine; however, under these conditions, sodium acetate and N-ethylmaleimide did not stimulate the growth of E. coli. It is proposed that low molecular weight thiols and intracellular pH may participate in the response of E. coli to betaine.
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Affiliation(s)
- G Smirnova
- Laboratory of Physiology of Microorganisms, Institute of Ecology and Genetics of Microorganisms, Russian Academy of Sciences
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25
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Peña A, Ramírez J, Rosas G, Calahorra M. Pyranine introduced by electroporation as an indicator of the internal pH of yeast. Folia Microbiol (Praha) 1994. [DOI: 10.1007/bf02814095] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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26
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Pinner E, Padan E, Schuldiner S. Kinetic properties of NhaB, a Na+/H+ antiporter from Escherichia coli. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(18)47190-6] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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27
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Padan E, Schuldiner S. Molecular physiology of Na+/H+ antiporters, key transporters in circulation of Na+ and H+ in cells. BIOCHIMICA ET BIOPHYSICA ACTA 1994; 1185:129-51. [PMID: 8167133 DOI: 10.1016/0005-2728(94)90204-6] [Citation(s) in RCA: 121] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- E Padan
- Department of Microbial and Molecular Ecology, Hebrew University of Jerusalem, Israel
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28
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McLaggan D, Naprstek J, Buurman E, Epstein W. Interdependence of K+ and glutamate accumulation during osmotic adaptation of Escherichia coli. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)42113-2] [Citation(s) in RCA: 169] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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29
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Oktyabrsky ON, Smirnova GV. Changes in redox potential of Escherichia coli culture and in extracellular glutathione status under osmotic shock. ACTA ACUST UNITED AC 1993. [DOI: 10.1016/0302-4598(93)80052-v] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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30
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Taglicht D, Padan E, Schuldiner S. Proton-sodium stoichiometry of NhaA, an electrogenic antiporter from Escherichia coli. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(18)53333-0] [Citation(s) in RCA: 132] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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31
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Rahav-Manor O, Carmel O, Karpel R, Taglicht D, Glaser G, Schuldiner S, Padan E. NhaR, a protein homologous to a family of bacterial regulatory proteins (LysR), regulates nhaA, the sodium proton antiporter gene in Escherichia coli. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(19)50037-0] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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32
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Shift-Reagent-Aided 23Na NMR Spectroscopy in Cellular, Tissue, and Whole-Organ Systems. ACTA ACUST UNITED AC 1992. [DOI: 10.1007/978-1-4757-9477-9_4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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33
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Chapter 2 Chemiosmotic systems and the basic principles of cell energetics. MOLECULAR MECHANISMS IN BIOENERGETICS 1992. [DOI: 10.1016/s0167-7306(08)60170-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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34
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Cayley S, Lewis BA, Guttman HJ, Record MT. Characterization of the cytoplasm of Escherichia coli K-12 as a function of external osmolarity. Implications for protein-DNA interactions in vivo. J Mol Biol 1991; 222:281-300. [PMID: 1960728 DOI: 10.1016/0022-2836(91)90212-o] [Citation(s) in RCA: 354] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The water-accessible volumes, the amounts of all significant osmolytes, and the protein concentration in the cytoplasm of aerobically grown Escherichia coli K-12 have been determined as a function of the osmolarity of the minimal growth medium. The volume of cytoplasmic water (Vcyto) decreases linearly with increasing osmolarity from 2.23(+/- 0.12) microliters/mg dry weight in cells grown at 0.10 OSM to 1.18(+/- 0.06) microliters/mg dry weight at 1.02 OSM. Above 0.28 OSM, growth rate decreases linearly with increasing osmolarity. The growth rate extrapolates to zero at an osmolarity of approximately 1.8, corresponding to an estimated Vcyto of 0.5(+/- 0.2) microliters/mg dry weight. Measurements of Vcyto in titrations of non-growing cells with the plasmolyzing agent NaCl were used to obtain volumes of "bound" water (presumably water of macromolecular hydration) and cytoplasmic osmotic coefficients for cells grown in medium of low (0.10 OSM) and moderate (0.28 OSM) osmolarity. The volume of bound water Vb is similar in the two osmotic conditions (Vb = 0.40(+/- 0.04) microliters/mg dry wt), and corresponds to approximately 0.5 g H2O/g cytoplasmic macromolecule. Since Vcyto decreases with increasing osmolarity, whereas Vb appears to be independent of osmolarity, water of hydration becomes a larger fraction of Vcyto as the osmolarity of the growth medium increases. Growth appears to cease at the osmolarity where Vcyto is approximately equal to Vb. K+ and glutamate (Glu-) are the only significant cytoplasmic osmolytes in cells grown in medium of low osmolarity. The amount of K+ greatly exceeds that of Glu-. Analysis of cytoplasmic electroneutrality indicates that the cytoplasm behaves like a concentrated solution of the K+ salt of cytoplasmic polyanions, in which the amount of additional electrolyte (K+ Glu-) increases with increasing osmolarity. As the osmolarity of the growth medium becomes very low, the cytoplasm approaches an electrolyte-free K+-polyanion solution. In vivo osmotic coefficients were determined from the variation of Vcyto with external osmolarity in plasmolysis titrations of non-growing cells. The values obtained (phi = 0.54(+/- 0.06) for cells grown at 0.10 OSM and phi = 0.71(+/- 0.11) at 0.28 OSM) indicate a high degree of non-ideality of intracellular ions arising from coulombic interactions between K+ and cytoplasmic polyanions. Analysis of these osmotic coefficients using polyelectrolyte theory indicates that the thermodynamic activity of cytoplasmic K+ increases from approximately 0.14 M in cells grown at an external osmolarity of 0.10 OSM to approximately 0.76 M at 1.02 OSM.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- S Cayley
- Program in Molecular Biology, University of Wisconsin-Madison 53706
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35
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Expression of a sodium proton antiporter (NhaA) in Escherichia coli is induced by Na+ and Li+ ions. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)54700-1] [Citation(s) in RCA: 77] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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36
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37
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Taglicht D, Padan E, Schuldiner S. Overproduction and purification of a functional Na+/H+ antiporter coded by nhaA (ant) from Escherichia coli. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)99161-1] [Citation(s) in RCA: 221] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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38
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Dibrov PA. The role of sodium ion transport in Escherichia coli energetics. BIOCHIMICA ET BIOPHYSICA ACTA 1991; 1056:209-24. [PMID: 1848102 DOI: 10.1016/s0005-2728(05)80052-0] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- P A Dibrov
- Department of Bioenergetics, A.N. Belozersky Laboratory of Molecular Biology and Bioorganic Chemistry, Moscow State University, U.S.S.R
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39
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Hallett D, Clark P, Macaskie L. Phosphatase production by aCitrobactersp. growing in batch cultures retarded by anaerobic or osmotic stress, and the effect of the osmoprotectant glycine betaine. FEMS Microbiol Lett 1991. [DOI: 10.1111/j.1574-6968.1991.tb04407.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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40
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Genetic analysis of potassium transport loci in Escherichia coli: evidence for three constitutive systems mediating uptake potassium. J Bacteriol 1991; 173:687-96. [PMID: 1987159 PMCID: PMC207060 DOI: 10.1128/jb.173.2.687-696.1991] [Citation(s) in RCA: 121] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The analysis of mutants of Escherichia coli that require elevated concentrations of K+ for growth has revealed two new genes, trkG, near minute 30 within the cryptic rac prophage, and trkH, near minute 87, the products of which affect constitutive K+ transport. The analysis of these and other trk mutations suggests that high rates of transport, previously considered to represent the activity of a single system, named TrkA, appear to be the sum of two systems, here named TrkG and TrkH. Each of these two is absolutely dependent on the product of the trkA gene, a cytoplasmic protein associated with the inner membrane (D. Bossemeyer, A. Borchard, D. C. Dosch, G. C. Helmer, W. Epstein, I. R. Booth, and E. P. Bakker, J. Biol. Chem. 264:16403-16410, 1989). The TrkH system is also dependent on the products of the trkH and trkE genes, while the TrkG system is also dependent on the product of the trkG gene and partially dependent on the product of the trkE gene. It is suggested that the trkH and trkG products are membrane proteins that form the transmembrane path for the K+ movement of the respective systems. Two mutations altering the trkA product reduce the affinity for K+ of both TrkG and TrkH, indicating that changes in peripheral protein can alter the conformation of the sites at which K+ is bound prior to transport. The TrkD system has a relatively modest rate of transport, is dependent solely on the product of the trkD gene, and is the sole saturable system for Cs+ uptake in this species (D. Bossemeyer, A. Schlösser, and E. P. Bakker, J. Bacteriol. 171:2219-2221, 1989).
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41
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Briasco CA, Ross DA, Robertson CR. A hollow-fiber reactor design for NMR studies of microbial cells. Biotechnol Bioeng 1990; 36:879-86. [DOI: 10.1002/bit.260360903] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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42
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Prince WS, Villarejo MR. Osmotic control of proU transcription is mediated through direct action of potassium glutamate on the transcription complex. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(18)38216-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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43
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McLaggan D, Logan TM, Lynn DG, Epstein W. Involvement of gamma-glutamyl peptides in osmoadaptation of Escherichia coli. J Bacteriol 1990; 172:3631-6. [PMID: 1972940 PMCID: PMC213336 DOI: 10.1128/jb.172.7.3631-3636.1990] [Citation(s) in RCA: 62] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Accumulation of K+ ions and glutamate plays a primary role in maintaining osmotic balance in Escherichia coli, as illustrated by the high concentrations of these ions present in cells growing in medium of high osmolality. We found that two gamma-glutamyl peptides and glutamine also accumulated during growth at high osmolarity. In a mutant unable to make trehalose growing in 1.3 osM medium, glutathione, gamma-glutamylglutamine, and glutamine accumulated to levels of 73, 33, and 140 mumol/g of protein, respectively. In such cells, K+ was present at 1,450 mumol/g of protein, indicating that glutathione and gamma-glutamylglutamine accounted for less than 10% of the low-molecular-weight anions accumulated with K+. However, glutathione is needed for wild-type osmotolerance in this species. A mutant deficient in glutathione because of an insertion in the gshA gene was unable to grow above 1.4 osM, grew more slowly at intermediate osmolarities, and took longer to adapt to growth following osmotic upshock. The involvement of glutathione in osmoregulation was independent of the effect of glutathione on K+ retention.
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Affiliation(s)
- D McLaggan
- Department of Molecular Genetics, University of Chicago, Illinois 60637
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44
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Pan JW, Macnab RM. Steady-state measurements of Escherichia coli sodium and proton potentials at alkaline pH support the hypothesis of electrogenic antiport. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(19)38839-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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45
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Delort AM, Dauphin G, Guyot J, Jeminet G. Study by NMR of the mode of action of monensin on Streptococcus faecalis de-energized and energized cells. BIOCHIMICA ET BIOPHYSICA ACTA 1989; 1013:11-20. [PMID: 2551382 DOI: 10.1016/0167-4889(89)90121-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Streptococcus faecalis was used as a bacterial model for studying the mode of action of monensin by NMR investigations. Experiments were carried out in two states, characterized by several complementary methods: (i) the resting (de-energized) cell which was considered as an inert biological membrane, on which cationic transport induced by the ionophore alone can be investigated; (ii) the active (energized) cell where the ionophore-sensitive response of the living organism, particularly the cation pumps and the glycolysis, is probed. Studies of resting cells were performed, with changing external ionic concentrations, in the presence of monensin, which is preferentially a sodium carrier. Internal and external Na+ and H+ were followed by corresponding 23Na and 31P (inorganic phosphate) NMR resonances, K+ fluxes were measured by atomic absorption. It was shown that the induced cationic movements were linked to the existing ionic gradients for K+ and Na+. 31P and 13C NMR spectra for the intermediary metabolites detected in active cells showed that glycolysis is dramatically modified in the presence of monensin.
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Affiliation(s)
- A M Delort
- Laboratoire de Chimie Organique Biologique, U.R.A. 485 du CNRS, Université Blaise Pascal Aubière, France
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46
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McMorrow I, Shuman HA, Sze D, Wilson DM, Wilson TH. Sodium/proton antiport is required for growth of Escherichia coli at alkaline pH. BIOCHIMICA ET BIOPHYSICA ACTA 1989; 981:21-6. [PMID: 2541789 DOI: 10.1016/0005-2736(89)90077-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Evidence is presented indicating that Escherichia coli requires the Na+/H+ antiporter and external sodium (or lithium) ion to grow at high pH. Cells were grown in plastic tubes containing medium with a very low Na+ content (5-15 microM). Normal cells grew at pH 7 or 8 with or without added Na+, but at pH 8.5 external Na was required for growth. A mutant with low antiporter activity failed to grow at pH 8.5 with or without Na+. On the other hand, another mutant with elevated antiporter activity grew at a higher pH than normal (pH 9) in the presence of added Na+ or Li+. Amiloride, an inhibitor of the antiporter, prevented cells from growing at pH 8.5 (plus Na+), although it had no effect on growth in media of lower pH values.
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Affiliation(s)
- I McMorrow
- Department of Cellular and Molecular Physiology, Harvard Medical School, Boston, MA 02115
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47
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Abstract
The capacity of organisms to respond to fluctuations in their osmotic environments is an important physiological process that determines their abilities to thrive in a variety of habitats. The primary response of bacteria to exposure to a high osmotic environment is the accumulation of certain solutes, K+, glutamate, trehalose, proline, and glycinebetaine, at concentrations that are proportional to the osmolarity of the medium. The supposed function of these solutes is to maintain the osmolarity of the cytoplasm at a value greater than the osmolarity of the medium and thus provide turgor pressure within the cells. Accumulation of these metabolites is accomplished by de novo synthesis or by uptake from the medium. Production of proteins that mediate accumulation or uptake of these metabolites is under osmotic control. This review is an account of the processes that mediate adaptation of bacteria to changes in their osmotic environment.
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48
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Knubovets TL, Revazov AV, Sibeldina LA, Eichhoff U. 23Na NMR measurement of the maximal rate of active sodium efflux from human red blood cells. Magn Reson Med 1989; 9:261-72. [PMID: 2541305 DOI: 10.1002/mrm.1910090211] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The method for 23Na NMR measurement of the maximal rate of active Na+ efflux from human red blood cells (RBC) is proposed. The nonpenetrating paramagnetic shift reagent (SR) bis(tripolyphosphate)dysprosium(III) complex is used to distinguish extracellular Na+ ions from intracellular. RBC are proved to retain their physiological activity in the presence of SR. Intracellular Na+ is shown to be 100% NMR visible. The levels of intracellular and extracellular Na+ and K+ ions are changed to decrease their concentration gradients across the erythrocyte membrane to make active Na+ efflux the only 23Na NMR measurable process; so the integrated areas of intra- and extracellular Na+ peaks remain invariant throughout the incubation period in the presence of 0.25 mM ouabain, a specific inhibitor of Na+, K+-ATPase. The accuracy of the proposed technique is evaluated to be 10%. The maximal Na+ efflux is determined to be 10.1 +/- 1.0 mM/h/liter of cells.
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Affiliation(s)
- T L Knubovets
- Institute of Chemical Physics, Academy of Science USSR, Moscow
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49
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Letellier L, Boulanger P. Involvement of ion channels in the transport of phage DNA through the cytoplasmic membrane of E. coli. Biochimie 1989; 71:167-74. [PMID: 2470417 DOI: 10.1016/0300-9084(89)90147-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Upon infection, phage DNA is transported through the bacterial cytoplasmic membrane. This crossing is accompanied by a transient increase in the permeability of the cytoplasmic membrane toward ions and small solutes. This has led several authors to propose that DNA might cross the cytoplasmic membrane through channels. In the first part of the review we present data that we obtained with phage T4 and that strongly support this proposal. We then present the structural and ionic characteristics of these channels. In the second part, we summarize data obtained by several authors concerning the permeability changes induced by different phages and show that these results are compatible with a model of phage DNA transfer through channels. Finally, we discuss the possible origin of these channels.
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Affiliation(s)
- L Letellier
- Laboratoire des Biomembranes, UA 1116, Université Paris Sud, Orsay, France
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50
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Wood JM. Proline porters effect the utilization of proline as nutrient or osmoprotectant for bacteria. J Membr Biol 1988; 106:183-202. [PMID: 3072423 DOI: 10.1007/bf01872157] [Citation(s) in RCA: 86] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Proline is utilized by all organisms as a protein constituent. It may also serve as a source of carbon, energy and nitrogen for growth or as an osmoprotectant. The molecular characteristics of the proline transport systems which mediate the multiple functions of proline in the Gram negative enteric bacteria, Escherichia coli and Salmonella typhimurium, are now becoming apparent. Recent research on those organisms has provided both protocols for the genetic and biochemical characterization of the enzymes mediating proline transport and molecular probes with which the degree of homology among the proline transport systems of archaebacteria, eubacteria and eukaryotes can be assessed. This review has provided a detailed summary of recent research on proline transport in E. coli and S. typhimurium; the properties of other organisms are cited primarily to illustrate the generality of those observations and to show where homologous proline transport systems might be expected to occur. The characteristics of proline transport in eukaryotic microorganisms have recently been reviewed (Horak, 1986).
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Affiliation(s)
- J M Wood
- Department of Chemistry and Biochemistry, University of Guelph, Ontario, Canada
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