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Beri D, Herring CD, Blahova S, Poudel S, Giannone RJ, Hettich RL, Lynd LR. Coculture with hemicellulose-fermenting microbes reverses inhibition of corn fiber solubilization by Clostridium thermocellum at elevated solids loadings. Biotechnol Biofuels 2021; 14:24. [PMID: 33461608 PMCID: PMC7814735 DOI: 10.1186/s13068-020-01867-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 12/24/2020] [Indexed: 05/10/2023]
Abstract
BACKGROUND The cellulolytic thermophile Clostridium thermocellum is an important biocatalyst due to its ability to solubilize lignocellulosic feedstocks without the need for pretreatment or exogenous enzyme addition. At low concentrations of substrate, C. thermocellum can solubilize corn fiber > 95% in 5 days, but solubilization declines markedly at substrate concentrations higher than 20 g/L. This differs for model cellulose like Avicel, on which the maximum solubilization rate increases in proportion to substrate concentration. The goal of this study was to examine fermentation at increasing corn fiber concentrations and investigate possible reasons for declining performance. RESULTS The rate of growth of C. thermocellum on corn fiber, inferred from CipA scaffoldin levels measured by LC-MS/MS, showed very little increase with increasing solids loading. To test for inhibition, we evaluated the effects of spent broth on growth and cellulase activity. The liquids remaining after corn fiber fermentation were found to be strongly inhibitory to growth on cellobiose, a substrate that does not require cellulose hydrolysis. Additionally, the hydrolytic activity of C. thermocellum cellulase was also reduced to less-than half by adding spent broth. Noting that > 15 g/L hemicellulose oligosaccharides accumulated in the spent broth of a 40 g/L corn fiber fermentation, we tested the effect of various model carbohydrates on growth on cellobiose and Avicel. Some compounds like xylooligosaccharides caused a decline in cellulolytic activity and a reduction in the maximum solubilization rate on Avicel. However, there were no relevant model compounds that could replicate the strong inhibition by spent broth on C. thermocellum growth on cellobiose. Cocultures of C. thermocellum with hemicellulose-consuming partners-Herbinix spp. strain LL1355 and Thermoanaerobacterium thermosaccharolyticum-exhibited lower levels of unfermented hemicellulose hydrolysis products, a doubling of the maximum solubilization rate, and final solubilization increased from 67 to 93%. CONCLUSIONS This study documents inhibition of C. thermocellum with increasing corn fiber concentration and demonstrates inhibition of cellulase activity by xylooligosaccharides, but further work is needed to understand why growth on cellobiose was inhibited by corn fiber fermentation broth. Our results support the importance of hemicellulose-utilizing coculture partners to augment C. thermocellum in the fermentation of lignocellulosic feedstocks at high solids loading.
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Affiliation(s)
- Dhananjay Beri
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA
- Centre for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
| | - Christopher D Herring
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA.
- Centre for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA.
- Enchi Corporation, Lebanon, NH, 03766, USA.
| | - Sofie Blahova
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA
| | - Suresh Poudel
- Centre for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
| | - Richard J Giannone
- Centre for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
| | - Robert L Hettich
- Centre for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
| | - Lee R Lynd
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA
- Centre for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
- Enchi Corporation, Lebanon, NH, 03766, USA
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Beri D, Olson DG, Holwerda EK, Lynd LR. Nicotinamide cofactor ratios in engineered strains of Clostridium thermocellum and Thermoanaerobacterium saccharolyticum. FEMS Microbiol Lett 2016; 363:fnw091. [PMID: 27190292 DOI: 10.1093/femsle/fnw091] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/07/2016] [Indexed: 12/30/2022] Open
Abstract
Clostridium thermocellum and Thermoanaerobacterium saccharolyticum are bacteria under investigation for production of biofuels from plant biomass. Thermoanaerobacterium saccharolyticum has been engineered to produce ethanol at high yield (>90% of theoretical) and titer (>70 g/l). Efforts to engineer C. thermocellum have not, to date, been as successful, and efforts are underway to transfer the ethanol production pathway from T. saccharolyticum to C. thermocellum One potential challenge in transferring metabolic pathways is the possibility of incompatible levels of nicotinamide cofactors. These cofactors (NAD(+), NADH, NADP(+) and NADPH) and their oxidation state are important in the context of microbial redox metabolism. In this study we directly measured the concentrations and reduced oxidized ratios of these cofactors in a number of strains of C. thermocellum and T. saccharolyticum by using acid/base extraction and enzymatic assays. We found that cofactor ratios are maintained in a fairly narrow range, regardless of the metabolic network modifications considered. We have found that the ratios are similar in both organisms, which is a relevant observation in the context of transferring the T. saccharolyticum ethanol production pathway to C. thermocellum.
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Affiliation(s)
- Dhananjay Beri
- Thayer School of Engineering, Dartmouth College, 14 Engineering Drive, Hanover, NH 03755, USA BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA
| | - Daniel G Olson
- Thayer School of Engineering, Dartmouth College, 14 Engineering Drive, Hanover, NH 03755, USA BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA
| | - Evert K Holwerda
- Thayer School of Engineering, Dartmouth College, 14 Engineering Drive, Hanover, NH 03755, USA BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA
| | - Lee R Lynd
- Thayer School of Engineering, Dartmouth College, 14 Engineering Drive, Hanover, NH 03755, USA BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA
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Kishko I, Harish B, Zayats V, Reha D, Tenner B, Beri D, Gustavsson T, Ettrich R, Carey J. Biphasic kinetic behavior of E. coli WrbA, an FMN-dependent NAD(P)H:quinone oxidoreductase. PLoS One 2012; 7:e43902. [PMID: 22952804 PMCID: PMC3430622 DOI: 10.1371/journal.pone.0043902] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2012] [Accepted: 07/27/2012] [Indexed: 11/24/2022] Open
Abstract
The E. coli protein WrbA is an FMN-dependent NAD(P)H:quinone oxidoreductase that has been implicated in oxidative defense. Three subunits of the tetrameric enzyme contribute to each of four identical, cavernous active sites that appear to accommodate NAD(P)H or various quinones, but not simultaneously, suggesting an obligate tetramer with a ping-pong mechanism in which NAD departs before oxidized quinone binds. The present work was undertaken to evaluate these suggestions and to characterize the kinetic behavior of WrbA. Steady-state kinetics results reveal that WrbA conforms to a ping-pong mechanism with respect to the constancy of the apparent Vmax to Km ratio with substrate concentration. However, the competitive/non-competitive patterns of product inhibition, though consistent with the general class of bi-substrate reactions, do not exclude a minor contribution from additional forms of the enzyme. NMR results support the presence of additional enzyme forms. Docking and energy calculations find that electron-transfer-competent binding sites for NADH and benzoquinone present severe steric overlap, consistent with the ping-pong mechanism. Unexpectedly, plots of initial velocity as a function of either NADH or benzoquinone concentration present one or two Michaelis-Menten phases depending on the temperature at which the enzyme is held prior to assay. The effect of temperature is reversible, suggesting an intramolecular conformational process. WrbA shares these and other details of its kinetic behavior with mammalian DT-diaphorase, an FAD-dependent NAD(P)H:quinone oxidoreductase. An extensive literature review reveals several other enzymes with two-plateau kinetic plots, but in no case has a molecular explanation been elucidated. Preliminary sedimentation velocity analysis of WrbA indicates a large shift in size of the multimer with temperature, suggesting that subunit assembly coupled to substrate binding may underlie the two-plateau behavior. An additional aim of this report is to bring under wider attention the apparently widespread phenomenon of two-plateau Michaelis-Menten plots.
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Affiliation(s)
- Iryna Kishko
- Institute of Nanobiology and Structural Biology, Global Change Research Center, Academy of Sciences of the Czech Republic, Nove Hrady, Czech Republic
- Faculty of Sciences, University of South Bohemia, Nove Hrady, Czech Republic
| | - Balasubramanian Harish
- Chemistry Department, Princeton University, Princeton, New Jersey, United States of America
| | - Vasilina Zayats
- Institute of Nanobiology and Structural Biology, Global Change Research Center, Academy of Sciences of the Czech Republic, Nove Hrady, Czech Republic
- Faculty of Sciences, University of South Bohemia, Nove Hrady, Czech Republic
| | - David Reha
- Institute of Nanobiology and Structural Biology, Global Change Research Center, Academy of Sciences of the Czech Republic, Nove Hrady, Czech Republic
| | - Brian Tenner
- Chemistry Department, Princeton University, Princeton, New Jersey, United States of America
| | - Dhananjay Beri
- Chemistry Department, Princeton University, Princeton, New Jersey, United States of America
| | - Tobias Gustavsson
- Department of Biochemistry and Structural Biology, Center for Molecular Protein Science, Lund University, Lund, Sweden
| | - Rüdiger Ettrich
- Institute of Nanobiology and Structural Biology, Global Change Research Center, Academy of Sciences of the Czech Republic, Nove Hrady, Czech Republic
- Faculty of Sciences, University of South Bohemia, Nove Hrady, Czech Republic
- * E-mail: (JC); (RE)
| | - Jannette Carey
- Chemistry Department, Princeton University, Princeton, New Jersey, United States of America
- * E-mail: (JC); (RE)
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Naylor J, Li J, Milligan CJ, Zeng F, Sukumar P, Hou B, Sedo A, Yuldasheva N, Majeed Y, Beri D, Jiang S, Seymour VAL, McKeown L, Kumar B, Harteneck C, O'Regan D, Wheatcroft SB, Kearney MT, Jones C, Porter KE, Beech DJ. Pregnenolone sulphate- and cholesterol-regulated TRPM3 channels coupled to vascular smooth muscle secretion and contraction. Circ Res 2010; 106:1507-15. [PMID: 20360246 DOI: 10.1161/circresaha.110.219329] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
RATIONALE Transient receptor potential melastatin (TRPM)3 is a calcium-permeable ion channel activated by the neurosteroid pregnenolone sulfate and positively coupled to insulin secretion in beta cells. Although vascular TRPM3 mRNA has been reported, there is no knowledge of TRPM3 protein or its regulation and function in the cardiovascular system. OBJECTIVE To determine the relevance and regulation of TRPM3 in vascular biology. METHODS AND RESULTS TRPM3 expression was detected at mRNA and protein levels in contractile and proliferating vascular smooth muscle cells. Calcium entry evoked by pregnenolone sulfate or sphingosine was suppressed by TRPM3 blocking antibody or knock-down of TRPM3 by RNA interference. Low-level constitutive TRPM3 activity was also detected. In proliferating cells, channel activity was coupled negatively to interleukin-6 secretion via a calcium-dependent mechanism. In freshly isolated aorta, TRPM3 positively modulated contractile responses independently of L-type calcium channels. Concentrations of pregnenolone sulfate required to evoke responses were higher than the known plasma concentrations of the steroids, leading to a screen for other stimulators. beta-Cyclodextrin was one of few stimulators of TRPM3, revealing the channels to be partially suppressed by endogenous cholesterol, the precursor of pregnenolone. Elevation of cholesterol further suppressed channel activity and loading with cholesterol to generate foam cells precluded observation of TRPM3 activity. CONCLUSIONS The data suggest functional relevance of TRPM3 in contractile and proliferating phenotypes of vascular smooth muscle cells, significance of constitutive channel activity, regulation by cholesterol, and potential value of pregnenolone sulfate in therapeutic vascular modulation.
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Affiliation(s)
- Jacqueline Naylor
- Multidisciplinary Cardiovascular Research Centre, University of Leeds, Leeds, LS2 9JT, United Kingdom
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Zervou T, Katelari A, Beri D, Inglezos I, Doudounakis S. Dehydration: a common clinical feature suggesting the diagnosis of CF in Greece. J Cyst Fibros 2008. [DOI: 10.1016/s1569-1993(08)60042-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Katelari A, Tzanoudaki M, Vrachnou E, Beri D, Liatsis M, Doudounakis S. 131 Basophil activation test for the early diagnosis of allergic bronchopulmonary aspergillosis (ABPA). J Cyst Fibros 2007. [DOI: 10.1016/s1569-1993(07)60120-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Beri D, Katelari A, Loukou I, Zervou T, Inglezos E, Liatsis M, Doudounakis S. 230 ABPA is not rare in CF patients under 6 years old: Epidemiological data in Greek CF patients for the period 1990–2005. J Cyst Fibros 2006. [DOI: 10.1016/s1569-1993(06)80212-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Singh RR, Malaviya AN, Malaviya R, Sharma M, Shandilya R, Taneja V, Khare SD, Beri D, Kumar A, Mehra NK. Effect of D-penicillamine on lymphocyte subsets: correlation with clinical response in rheumatoid arthritis. J Assoc Physicians India 1994; 42:201-4. [PMID: 7860508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We studied the effects of D-penicillamine (DP) on the clinical response, immunoinflammatory parameters and the lymphocyte subsets in 46 patients with rheumatoid arthritis (RA). Patients were evaluated before the start of the drug and then at 3 and 9 months during the follow up. 38 of 46 (82.6%) patients could continue DP treatment for over 9 months, while in 8 the drug was withdrawn due to adverse effects. Improvement in the various disease activity indices of more than 50% (responders) was seen in 25 of 38 (65.8%) patients. Responders showed a significant decrease in the serum IgA and IgM at 9 months, and in IgM only at 3 months. The serum levels of C3 and C4 did not show any significant change. Serum levels of C-reactive protein and rheumatoid factor (RF) showed a significant decrease at 3 and 9 months. A significant decrease in CD3+ and CD4+ lymphocytes along with a fall in CD4+/CD8+ lymphocyte ratio was also seen in responders at 3 and 9 months, compared to the baseline. Our results suggest that DP may have immunomodulatory action in RA.
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Affiliation(s)
- R R Singh
- Department of Medicine, All India Institute of Medical Sciences, New Delhi
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Abstract
Additions in five steps were made, as a possible therapeutic measure, to the diet of 27 patients with rheumatoid arthritis (RA) after a period of two weeks of a basal isocaloric diet free from pulses, cereals, milk, and non-vegetarian protein foods. Fourteen patients finally took part in the trial, 10 (71%) of whom showed significant clinical improvement. Only three patients (11%) adhered to the diet for a period of 10 months. The others discontinued the diet and were then treated with conventional disease modifying drugs. The study indicates that dietary factors may influence inflammatory response in RA.
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Affiliation(s)
- D Beri
- Department of Medicine, All India Institute of Medical Sciences, New Delhi
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