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Fawcett LP, Fringer VS, Sieber JR, Maurer-Jones MA. The effect of plastic additives on Shewanella oneidensis growth and function. Environ Sci Process Impacts 2021; 23:956-966. [PMID: 34085083 DOI: 10.1039/d1em00108f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Plastic waste has the potential for significant consequences on various ecosystems; yet, there are gaps in our understanding of the interaction of bacteria with polymer additives. We studied the impact of representative additive molecules to the viability and cell function of Shewanella oneidensis MR-1. Specifically, we explored the toxicity of three bisphenols (bisphenol A (BPA), bisphenol S (BPS), and tetrabromo bisphenol A (TBBPA)) and two diesters (dibutyl sebacate (DBS) and diisobutyl phthalate (DIBP)) in order to evaluate the generalizability of toxicity based on similar molecular structures. TBBPA caused significant, dose-dependent decreases in viability for acute (4 h) exposures in aerobic and anaerobic conditions. While the other 4 additives showed no significant toxicity upon 4 h exposures, chronic (2 day) anaerobic exposures revealed a significant impact to growth. BPA and BPS cause a significant decrease in growth rates for all exposure doses (8-131 μM) while DBS and DIBP had decreases in growth for the lowest exposure concentrations, though recovered to growth rates similar to the control at the highest concentrations. This highlights that S. oneidensis may have the ability to use the diesters as a carbon source if present in high enough concentrations. Riboflavin secretion was monitored as a marker of cellular health. Most additives stimulated riboflavin secretion as a survival response. Yet, there was no generalizable trend observed for these molecules, indicating the importance of considering the nuances of molecular structure to toxicity responses and the need for further work to understand the consequences of plastic waste in our environment.
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Affiliation(s)
- Liam P Fawcett
- Department of Chemistry and Biochemistry, University of Minnesota Duluth, Duluth, MN, USA55812.
| | - Victoria S Fringer
- Department of Chemistry and Biochemistry, University of Minnesota Duluth, Duluth, MN, USA55812.
| | - Jessica R Sieber
- Department of Biology, University of Minnesota Duluth, Duluth, MN, USA55812
| | - Melissa A Maurer-Jones
- Department of Chemistry and Biochemistry, University of Minnesota Duluth, Duluth, MN, USA55812.
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2
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James KL, Kung JW, Crable BR, Mouttaki H, Sieber JR, Nguyen HH, Yang Y, Xie Y, Erde J, Wofford NQ, Karr EA, Loo JA, Ogorzalek Loo RR, Gunsalus RP, McInerney MJ. Syntrophus aciditrophicus uses the same enzymes in a reversible manner to degrade and synthesize aromatic and alicyclic acids. Environ Microbiol 2019; 21:1833-1846. [PMID: 30895699 PMCID: PMC6488403 DOI: 10.1111/1462-2920.14601] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 03/12/2019] [Accepted: 03/19/2019] [Indexed: 12/12/2022]
Abstract
Syntrophy is essential for the efficient conversion of organic carbon to methane in natural and constructed environments, but little is known about the enzymes involved in syntrophic carbon and electron flow. Syntrophus aciditrophicus strain SB syntrophically degrades benzoate and cyclohexane-1-carboxylate and catalyses the novel synthesis of benzoate and cyclohexane-1-carboxylate from crotonate. We used proteomic, biochemical and metabolomic approaches to determine what enzymes are used for fatty, aromatic and alicyclic acid degradation versus for benzoate and cyclohexane-1-carboxylate synthesis. Enzymes involved in the metabolism of cyclohex-1,5-diene carboxyl-CoA to acetyl-CoA were in high abundance in S. aciditrophicus cells grown in pure culture on crotonate and in coculture with Methanospirillum hungatei on crotonate, benzoate or cyclohexane-1-carboxylate. Incorporation of 13 C-atoms from 1-[13 C]-acetate into crotonate, benzoate and cyclohexane-1-carboxylate during growth on these different substrates showed that the pathways are reversible. A protein conduit for syntrophic reverse electron transfer from acyl-CoA intermediates to formate was detected. Ligases and membrane-bound pyrophosphatases make pyrophosphate needed for the synthesis of ATP by an acetyl-CoA synthetase. Syntrophus aciditrophicus, thus, uses a core set of enzymes that operates close to thermodynamic equilibrium to conserve energy in a novel and highly efficient manner.
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Affiliation(s)
- Kimberly L. James
- Department of Microbiology and Plant Biology, University of
Oklahoma, Norman, OK, 73019
| | - Johannes W. Kung
- Department of Microbiology and Plant Biology, University of
Oklahoma, Norman, OK, 73019
| | - Bryan R. Crable
- Department of Microbiology and Plant Biology, University of
Oklahoma, Norman, OK, 73019
| | - Housna Mouttaki
- Department of Microbiology and Plant Biology, University of
Oklahoma, Norman, OK, 73019
| | - Jessica R. Sieber
- Department of Microbiology and Plant Biology, University of
Oklahoma, Norman, OK, 73019
| | - Hong H. Nguyen
- Department of Chemistry & Biochemistry, University of
California, Los Angeles 90095
| | - Yanan Yang
- Department of Chemistry & Biochemistry, University of
California, Los Angeles 90095
| | - Yongming Xie
- Department of Chemistry & Biochemistry, University of
California, Los Angeles 90095
| | - Jonathan Erde
- Department of Chemistry & Biochemistry, University of
California, Los Angeles 90095
| | - Neil Q. Wofford
- Department of Microbiology and Plant Biology, University of
Oklahoma, Norman, OK, 73019
| | - Elizabeth A. Karr
- Department of Microbiology and Plant Biology, University of
Oklahoma, Norman, OK, 73019
- Price Family Foundation Institute of Structural Biology,
University of Oklahoma, Norman, OK, 73019
| | - Joseph A. Loo
- UCLA DOE Institute, University of California, Los Angeles
CA 90095
- Department of Chemistry & Biochemistry, University of
California, Los Angeles 90095
| | - Rachel R. Ogorzalek Loo
- UCLA DOE Institute, University of California, Los Angeles
CA 90095
- Department of Chemistry & Biochemistry, University of
California, Los Angeles 90095
| | - Robert P. Gunsalus
- Department of Microbiology, Immunology, and Molecular
Genetics, University of California, Los Angeles, CA, USA
- UCLA-Molecular Biology Institute, University of California,
Los Angeles, CA USA
- UCLA DOE Institute, University of California, Los Angeles
CA 90095
| | - Michael J. McInerney
- Department of Microbiology and Plant Biology, University of
Oklahoma, Norman, OK, 73019
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3
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Sheik CS, Sieber JR, Badalamenti JP, Carden K, Olson A. Complete Genome Sequence of Desulfovibrio desulfuricans Strain G11, a Model Sulfate-Reducing, Hydrogenotrophic, and Syntrophic Partner Organism. Genome Announc 2017; 5:e01207-17. [PMID: 29074670 PMCID: PMC5658508 DOI: 10.1128/genomea.01207-17] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Accepted: 09/26/2017] [Indexed: 11/20/2022]
Abstract
Here, we report the draft genome of the Gram-negative, sulfate-reducing bacterium Desulfovibrio desulfuricans strain G11. Isolated from a rumen fluid enrichment, this culture has been a model syntrophic partner due to its metabolic flexibility. The assembly yielded a single circular chromosome of 3,414,943 bp and a 57% G+C content.
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Affiliation(s)
- Cody S Sheik
- Department of Biology, University of Minnesota-Duluth, Duluth, Minnesota, USA
- Large Lakes Observatory, University of Minnesota-Duluth, Duluth, Minnesota, USA
| | - Jessica R Sieber
- Department of Biology, University of Minnesota-Duluth, Duluth, Minnesota, USA
| | - Jonathan P Badalamenti
- Department of Microbiology and BioTechnology Institute, University of Minnesota, Saint Paul, Minnesota, USA
| | - Kendall Carden
- Department of Biology, University of Minnesota-Duluth, Duluth, Minnesota, USA
| | - Adam Olson
- Department of Biology, University of Minnesota-Duluth, Duluth, Minnesota, USA
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4
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Crable BR, Sieber JR, Mao X, Alvarez-Cohen L, Gunsalus R, Ogorzalek Loo RR, Nguyen H, McInerney MJ. Membrane Complexes of Syntrophomonas wolfei Involved in Syntrophic Butyrate Degradation and Hydrogen Formation. Front Microbiol 2016; 7:1795. [PMID: 27881975 PMCID: PMC5101538 DOI: 10.3389/fmicb.2016.01795] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 10/25/2016] [Indexed: 11/18/2022] Open
Abstract
Syntrophic butyrate metabolism involves the thermodynamically unfavorable production of hydrogen and/or formate from the high potential electron donor, butyryl-CoA. Such redox reactions can occur only with energy input by a process called reverse electron transfer. Previous studies have demonstrated that hydrogen production from butyrate requires the presence of a proton gradient, but the biochemical machinery involved has not been clearly elucidated. In this study, the gene and enzyme systems involved in reverse electron transfer by Syntrophomonas wolfei were investigated using proteomic and gene expression approaches. S. wolfei was grown in co-culture with Methanospirillum hungatei or Dehalococcoides mccartyi under conditions requiring reverse electron transfer and compared to both axenic S. wolfei cultures and co-cultures grown in conditions that do not require reverse electron transfer. Blue native gel analysis of membranes solubilized from syntrophically grown cells revealed the presence of a membrane-bound hydrogenase, Hyd2, which exhibited hydrogenase activity during in gel assays. Bands containing a putative iron-sulfur (FeS) oxidoreductase were detected in membranes of crotonate-grown and butyrate grown S. wolfei cells. The genes for the corresponding hydrogenase subunits, hyd2ABC, were differentially expressed at higher levels during syntrophic butyrate growth when compared to growth on crotonate. The expression of the FeS oxidoreductase gene increased when S. wolfei was grown with M. hungatei. Additional membrane-associated proteins detected included FoF1 ATP synthase subunits and several membrane transporters that may aid syntrophic growth. Furthermore, syntrophic butyrate metabolism can proceed exclusively by interspecies hydrogen transfer, as demonstrated by growth with D. mccartyi, which is unable to use formate. These results argue for the importance of Hyd2 and FeS oxidoreductase in reverse electron transfer during syntrophic butyrate degradation.
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Affiliation(s)
- Bryan R. Crable
- Department of Microbiology and Plant Biology, University of Oklahoma, NormanOK, USA
| | - Jessica R. Sieber
- Department of Microbiology and Plant Biology, University of Oklahoma, NormanOK, USA
| | - Xinwei Mao
- Department of Civil and Environmental Engineering, University of California, Berkeley, BerkeleyCA, USA
| | - Lisa Alvarez-Cohen
- Department of Civil and Environmental Engineering, University of California, Berkeley, BerkeleyCA, USA
| | - Robert Gunsalus
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los AngelesCA, USA
| | - Rachel R. Ogorzalek Loo
- Department of Biological Chemistry, University of California, Los Angeles, Los AngelesCA, USA
| | - Hong Nguyen
- Department of Biological Chemistry, University of California, Los Angeles, Los AngelesCA, USA
| | - Michael J. McInerney
- Department of Microbiology and Plant Biology, University of Oklahoma, NormanOK, USA
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5
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James KL, Ríos-Hernández LA, Wofford NQ, Mouttaki H, Sieber JR, Sheik CS, Nguyen HH, Yang Y, Xie Y, Erde J, Rohlin L, Karr EA, Loo JA, Ogorzalek Loo RR, Hurst GB, Gunsalus RP, Szweda LI, McInerney MJ. Pyrophosphate-Dependent ATP Formation from Acetyl Coenzyme A in Syntrophus aciditrophicus, a New Twist on ATP Formation. mBio 2016; 7:e01208-16. [PMID: 27531911 PMCID: PMC4992975 DOI: 10.1128/mbio.01208-16] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Accepted: 07/12/2016] [Indexed: 11/29/2022] Open
Abstract
UNLABELLED Syntrophus aciditrophicus is a model syntrophic bacterium that degrades key intermediates in anaerobic decomposition, such as benzoate, cyclohexane-1-carboxylate, and certain fatty acids, to acetate when grown with hydrogen-/formate-consuming microorganisms. ATP formation coupled to acetate production is the main source for energy conservation by S. aciditrophicus However, the absence of homologs for phosphate acetyltransferase and acetate kinase in the genome of S. aciditrophicus leaves it unclear as to how ATP is formed, as most fermentative bacteria rely on these two enzymes to synthesize ATP from acetyl coenzyme A (CoA) and phosphate. Here, we combine transcriptomic, proteomic, metabolite, and enzymatic approaches to show that S. aciditrophicus uses AMP-forming, acetyl-CoA synthetase (Acs1) for ATP synthesis from acetyl-CoA. acs1 mRNA and Acs1 were abundant in transcriptomes and proteomes, respectively, of S. aciditrophicus grown in pure culture and coculture. Cell extracts of S. aciditrophicus had low or undetectable acetate kinase and phosphate acetyltransferase activities but had high acetyl-CoA synthetase activity under all growth conditions tested. Both Acs1 purified from S. aciditrophicus and recombinantly produced Acs1 catalyzed ATP and acetate formation from acetyl-CoA, AMP, and pyrophosphate. High pyrophosphate levels and a high AMP-to-ATP ratio (5.9 ± 1.4) in S. aciditrophicus cells support the operation of Acs1 in the acetate-forming direction. Thus, S. aciditrophicus has a unique approach to conserve energy involving pyrophosphate, AMP, acetyl-CoA, and an AMP-forming, acetyl-CoA synthetase. IMPORTANCE Bacteria use two enzymes, phosphate acetyltransferase and acetate kinase, to make ATP from acetyl-CoA, while acetate-forming archaea use a single enzyme, an ADP-forming, acetyl-CoA synthetase, to synthesize ATP and acetate from acetyl-CoA. Syntrophus aciditrophicus apparently relies on a different approach to conserve energy during acetyl-CoA metabolism, as its genome does not have homologs to the genes for phosphate acetyltransferase and acetate kinase. Here, we show that S. aciditrophicus uses an alternative approach, an AMP-forming, acetyl-CoA synthetase, to make ATP from acetyl-CoA. AMP-forming, acetyl-CoA synthetases were previously thought to function only in the activation of acetate to acetyl-CoA.
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Affiliation(s)
- Kimberly L James
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, Oklahoma, USA
| | - Luis A Ríos-Hernández
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, Oklahoma, USA
| | - Neil Q Wofford
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, Oklahoma, USA
| | - Housna Mouttaki
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, Oklahoma, USA
| | - Jessica R Sieber
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, Oklahoma, USA
| | - Cody S Sheik
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, Oklahoma, USA
| | - Hong H Nguyen
- Department of Biological Chemistry, University of California Los Angeles, Los Angeles, California, USA
| | - Yanan Yang
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California, USA
| | - Yongming Xie
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California, USA
| | - Jonathan Erde
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California, USA
| | - Lars Rohlin
- Department of Microbiology, Immunology and Molecular Genetics, University of California Los Angeles, Los Angeles, California, USA
| | - Elizabeth A Karr
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, Oklahoma, USA
| | - Joseph A Loo
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California, USA Department of Biological Chemistry, University of California Los Angeles, Los Angeles, California, USA
| | - Rachel R Ogorzalek Loo
- Department of Biological Chemistry, University of California Los Angeles, Los Angeles, California, USA
| | - Gregory B Hurst
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Robert P Gunsalus
- Department of Microbiology, Immunology and Molecular Genetics, University of California Los Angeles, Los Angeles, California, USA
| | - Luke I Szweda
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA
| | - Michael J McInerney
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, Oklahoma, USA
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6
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Sieber JR, Crable BR, Sheik CS, Hurst GB, Rohlin L, Gunsalus RP, McInerney MJ. Proteomic analysis reveals metabolic and regulatory systems involved in the syntrophic and axenic lifestyle of Syntrophomonas wolfei. Front Microbiol 2015; 6:115. [PMID: 25717324 PMCID: PMC4324140 DOI: 10.3389/fmicb.2015.00115] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 01/29/2015] [Indexed: 11/13/2022] Open
Abstract
Microbial syntrophy is a vital metabolic interaction necessary for the complete oxidation of organic biomass to methane in all-anaerobic ecosystems. However, this process is thermodynamically constrained and represents an ecosystem-level metabolic bottleneck. To gain insight into the physiology of this process, a shotgun proteomics approach was used to quantify the protein landscape of the model syntrophic metabolizer, Syntrophomonas wolfei, grown axenically and syntrophically with Methanospirillum hungatei. Remarkably, the abundance of most proteins as represented by normalized spectral abundance factor (NSAF) value changed very little between the pure and coculture growth conditions. Among the most abundant proteins detected were GroEL and GroES chaperonins, a small heat shock protein, and proteins involved in electron transfer, beta-oxidation, and ATP synthesis. Several putative energy conservation enzyme systems that utilize NADH and ferredoxin were present. The abundance of an EtfAB2 and the membrane-bound iron-sulfur oxidoreductase (Swol_0698 gene product) delineated a potential conduit for electron transfer between acyl-CoA dehydrogenases and membrane redox carriers. Proteins detected only when S. wolfei was grown with M. hungatei included a zinc-dependent dehydrogenase with a GroES domain, whose gene is present in genomes in many organisms capable of syntrophy, and transcriptional regulators responsive to environmental stimuli or the physiological status of the cell. The proteomic analysis revealed an emphasis on macromolecular stability and energy metabolism by S. wolfei and presence of regulatory mechanisms responsive to external stimuli and cellular physiological status.
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Affiliation(s)
- Jessica R. Sieber
- Department of Botany and Microbiology, University of OklahomaNorman, OK, USA
| | - Bryan R. Crable
- Department of Botany and Microbiology, University of OklahomaNorman, OK, USA
| | - Cody S. Sheik
- Department of Geological Sciences, University of MichiganAnn Arbor, MI, USA
| | - Gregory B. Hurst
- Chemical Sciences Division, Oak Ridge National LaboratoryOak Ridge, TN, USA
| | - Lars Rohlin
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los AngelesLos Angeles, CA, USA
| | - Robert P. Gunsalus
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los AngelesLos Angeles, CA, USA
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Sieber JR, Le HM, McInerney MJ. The importance of hydrogen and formate transfer for syntrophic fatty, aromatic and alicyclic metabolism. Environ Microbiol 2013; 16:177-88. [DOI: 10.1111/1462-2920.12269] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Revised: 08/14/2013] [Accepted: 08/26/2013] [Indexed: 11/28/2022]
Affiliation(s)
- Jessica R. Sieber
- Department of Microbiology and Plant Biology; University of Oklahoma; Norman OK 73019 USA
| | - Huynh M. Le
- Department of Microbiology and Plant Biology; University of Oklahoma; Norman OK 73019 USA
| | - Michael J. McInerney
- Department of Microbiology and Plant Biology; University of Oklahoma; Norman OK 73019 USA
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8
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Abstract
Syntrophy is a tightly coupled mutualistic interaction between hydrogen-/formate-producing and hydrogen-/formate-using microorganisms that occurs throughout the microbial world. Syntrophy is essential for global carbon cycling, waste decomposition, and biofuel production. Reverse electron transfer, e.g., the input of energy to drive critical redox reactions, is a defining feature of syntrophy. Genomic analyses indicate multiple systems for reverse electron transfer, including ion-translocating ferredoxin:NAD(+) oxidoreductase and hydrogenases, two types of electron transfer flavoprotein:quinone oxidoreductases, and other quinone reactive complexes. Confurcating hydrogenases that couple the favorable production of hydrogen from reduced ferredoxin with the unfavorable production of hydrogen from NADH are present in almost all syntrophic metabolizers, implicating their critical role in syntrophy. Transcriptomic analysis shows upregulation of many genes without assigned functions in the syntrophic lifestyle. High-throughput technologies provide insight into the mechanisms used to establish and maintain syntrophic consortia and conserve energy from reactions that operate close to thermodynamic equilibrium.
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Affiliation(s)
- Jessica R Sieber
- Department of Botany and Microbiology, University of Oklahoma, Norman, 73019, USA.
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9
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Sieber JR, Sims DR, Han C, Kim E, Lykidis A, Lapidus AL, McDonnald E, Rohlin L, Culley DE, Gunsalus R, McInerney MJ. The genome of Syntrophomonas wolfei: new insights into syntrophic metabolism and biohydrogen production. Environ Microbiol 2010; 12:2289-301. [PMID: 21966920 DOI: 10.1111/j.1462-2920.2010.02237.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Syntrophomonas wolfei is a specialist, evolutionarily adapted for syntrophic growth with methanogens and other hydrogen- and/or formate-using microorganisms. This slow-growing anaerobe has three putative ribosome RNA operons, each of which has 16S rRNA and 23S rRNA genes of different length and multiple 5S rRNA genes. The genome also contains 10 RNA-directed, DNA polymerase genes. Genomic analysis shows that S. wolfei relies solely on the reduction of protons, bicarbonate or unsaturated fatty acids to re-oxidize reduced cofactors. Syntrophomonas wolfei lacks the genes needed for aerobic or anaerobic respiration and has an exceptionally limited ability to create ion gradients. An ATP synthase and a pyrophosphatase were the only systems detected capable of creating an ion gradient. Multiple homologues for β-oxidation genes were present even though S. wolfei uses a limited range of fatty acids from four to eight carbons in length.Syntrophomonas wolfei, other syntrophic metabolizers with completed genomic sequences, and thermophilic anaerobes known to produce high molar ratios of hydrogen from glucose have genes to produce H(2) from NADH by an electron bifurcation mechanism. Comparative genomic analysis also suggests that formate production from NADH may involve electron bifurcation. A membrane-bound, iron-sulfur oxidoreductase found in S. wolfei and Syntrophus aciditrophicus may be uniquely involved in reverse electron transport during syntrophic fatty acid metabolism. The genome sequence of S. wolfei reveals several core reactions that may be characteristic of syntrophic fatty acid metabolism and illustrates how biological systems produce hydrogen from thermodynamically difficult reactions.
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Affiliation(s)
- Jessica R Sieber
- Department of Botany and Microbiology, University of Oklahoma, Norman, OK 73019, USA
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10
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Abstract
Syntrophy is an essential intermediary step in the anaerobic conversion of organic matter to methane where metabolically distinct microorganisms are tightly linked by the need to maintain the exchanged metabolites at very low concentrations. Anaerobic syntrophy is thermodynamically constrained, and is probably a prime reason why it is difficult to culture microbes as these approaches disrupt consortia. Reconstruction of artificial syntrophic consortia has allowed uncultured syntrophic metabolizers and methanogens to be optimally grown and studied biochemically. The pathways for syntrophic acetate, propionate and longer chain fatty acid metabolism are mostly understood, but key steps involved in benzoate breakdown and cyclohexane carboxylate formation are unclear. Syntrophic metabolism requires reverse electron transfer, close physical contact, and metabolic synchronization of the syntrophic partners. Genomic analyses reveal that multiple mechanisms exist for reverse electron transfer. Surprisingly, the flagellum functions were implicated in ensuring close physical proximity and synchronization of the syntrophic partners.
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Affiliation(s)
- Michael J. McInerney
- Department of Botany and Microbiology, University of Oklahoma, 770 Van Vleet Oval, Norman, Oklahoma 73019, USA; phone: 405-325-6050; fax: 405-325-7619
| | - Jessica R. Sieber
- Department of Botany and Microbiology, University of Oklahoma, 770 Van Vleet Oval, Norman, Oklahoma 73019, USA; phone: 405-325-6050; fax: 405-325-7619
| | - Robert P. Gunsalus
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, 1602 Molecular Science Building, 609 Charles Young Drive East, Los Angeles, CA 90095-1489, USA phone: 310-206-8201; fax: 310-206-5231
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11
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Mackey EA, Cronise MP, Fales CN, Greenberg RR, Leigh SD, Long SE, Marlow AF, Murphy KE, Oflaz R, Sieber JR, Rearick MS, Wood LJ, Yu LL, Wilson SA, Briggs PH, Brown ZA, Budahn J, Kane PF, Hall WL. Development and certification of the new SRM 695 trace elements in multi-nutrient fertilizer. Anal Bioanal Chem 2007; 387:2401-9. [PMID: 17265084 DOI: 10.1007/s00216-007-1124-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2006] [Revised: 01/10/2007] [Accepted: 01/11/2007] [Indexed: 10/23/2022]
Abstract
During the past seven years, several states within the US have enacted regulations that limit the amounts of selected non-nutritive elements in fertilizers. Internationally, several countries, including Japan, China, and Australia, and the European Union also limit the amount of selected elements in fertilizers. The elements of interest include As, Cd, Co, Cr, Cu, Hg, Mo, Ni, Pb, Se, and Zn. Fertilizer manufacturers and state regulatory authorities, faced with meeting and verifying these limits, need to develop analytical methods for determination of the elements of concern and to validate results obtained using these methods. Until now, there were no certified reference materials available with certified mass fraction values for all elements of interest in a blended, multi-nutrient fertilizer matrix. A new standard reference material (SRM) 695 trace elements in multi-nutrient fertilizer, has been developed to help meet these needs. SRM 695 has recently been issued with certified mass fraction values for seventeen elements, reference values for an additional five elements, and information values for two elements. The certificate of analysis includes an addendum listing percentage recovery for eight of these elements, determined using an acid-extraction inductively-coupled plasma optical-emission spectrometry (ICP-OES) method recently developed and tested by members of the Association of American Plant Food Control Officials.
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Affiliation(s)
- E A Mackey
- National Institute of Standards and Technology, 100 Bureau Drive, Mailstop 8395, Gaithersburg, MD 20899, USA.
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12
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Sieber JR, Powers CA, Baggs JR, Knapp JM, Sileo CM. Missing in action: nurses in the media. Am J Nurs 1998; 98:55-6. [PMID: 9917269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Affiliation(s)
- J R Sieber
- University of Rochester, School of Nursing, New York, USA
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13
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Pella PA, Kingston HM, Sieber JR, Feng LY. Effect of sample dissolution procedures on X-ray spectrometric analysis of biological materials. Anal Chem 1983; 55:1193-4. [PMID: 6881526 DOI: 10.1021/ac00258a054] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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