The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
Paul Dupree - One of the best experts on this subject based on the ideXlab platform.
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Two Softwood GUX clades are responsible for distinct glucuronic acid patterns on xylan.
2021Co-Authors: Jan J. Lyczakowski, Oliver M. Terrett, Christina Fleischmann, Henry Temple, Glenn Thorlby, Mathias Sorieul, Paul DupreeAbstract:Wood of coniferous (Softwood) trees, is a globally significant carbon sink and an important source of biomass for industrial applications. Despite its importance, very little is known about the genetic basis of Softwood biosynthesis. Glucomannan and xylan are the main hemicelluloses in Softwood secondary cell walls. Xylan interacts with the cellulose fibrils in a two-fold screw configuration. Moreover, we have shown that xylan GUX (GlucUronic acid substitution of Xylan)-dependent branching with glucuronic acid is critical for biomass recalcitrance. Here, we investigated the decoration patterns of xylan by Softwood GUX enzymes. Using in vitro and in planta assays we demonstrate that two distinct clades of conifer GUX enzymes are active glucuronyltransferases. Interestingly, these enzymes have different specific activities, with one adding evenly spaced GlcA branches and the other one being also capable of glucuronidating two consecutive xyloses. Since xylan patterning might modulate xylan-cellulose and xylan-lignin interactions, our result further the understanding of Softwood biosynthesis and can contribute to strategies aimed at modifying Softwood cell wall properties.
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Molecular architecture of Softwood revealed by solid-state NMR
Nature Communications, 2019Co-Authors: Oliver M. Terrett, Jan J. Lyczakowski, W. Trent Franks, Dinu Iuga, Steven P Brown, R. Dupree, Li Yu, Paul DupreeAbstract:Economically important Softwood from conifers is mainly composed of the polysaccharides cellulose, galactoglucomannan and xylan, and the phenolic polymer, lignin. The interactions between these polymers lead to wood mechanical strength and must be overcome in biorefining. Here, we use ^13C multidimensional solid-state NMR to analyse the polymer interactions in never-dried cell walls of the Softwood, spruce. In contrast to some earlier Softwood cell wall models, most of the xylan binds to cellulose in the two-fold screw conformation. Moreover, galactoglucomannan alters its conformation by intimately binding to the surface of cellulose microfibrils in a semi-crystalline fashion. Some galactoglucomannan and xylan bind to the same cellulose microfibrils, and lignin is associated with both of these cellulose-bound polysaccharides. We propose a model of Softwood molecular architecture which explains the origin of the different cellulose environments observed in the NMR experiments. Our model will assist strategies for improving wood usage in a sustainable bioeconomy.Understanding the interactions between the constituents of the cell walls in wood is important for understanding the mechanical properties. Here, the authors report on a solid-state NMR study of never-dried Softwood, noticing differences to previous reports and develop a model of Softwood architecture.
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Molecular architecture of Softwood revealed by solid-state NMR
Nature communications, 2019Co-Authors: Oliver M. Terrett, Jan J. Lyczakowski, W. Trent Franks, Dinu Iuga, Steven P Brown, R. Dupree, Paul DupreeAbstract:Economically important Softwood from conifers is mainly composed of the polysaccharides cellulose, galactoglucomannan and xylan, and the phenolic polymer, lignin. The interactions between these polymers lead to wood mechanical strength and must be overcome in biorefining. Here, we use 13C multidimensional solid-state NMR to analyse the polymer interactions in never-dried cell walls of the Softwood, spruce. In contrast to some earlier Softwood cell wall models, most of the xylan binds to cellulose in the two-fold screw conformation. Moreover, galactoglucomannan alters its conformation by intimately binding to the surface of cellulose microfibrils in a semi-crystalline fashion. Some galactoglucomannan and xylan bind to the same cellulose microfibrils, and lignin is associated with both of these cellulose-bound polysaccharides. We propose a model of Softwood molecular architecture which explains the origin of the different cellulose environments observed in the NMR experiments. Our model will assist strategies for improving wood usage in a sustainable bioeconomy.
John Ralph - One of the best experts on this subject based on the ideXlab platform.
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syringyl lignin production in conifers proof of concept in a pine tracheary element system
Proceedings of the National Academy of Sciences of the United States of America, 2015Co-Authors: Armin Wagner, Yuki Tobimatsu, Barbara Geddes, Lorelle Phillips, Heather Flint, Fachuang Lu, John RalphAbstract:Conifers (Softwoods) naturally lack syringyl units in their lignins, rendering lignocellulosic materials from such species more difficult to process than syringyl-rich hardwood species. Using a transformable Pinus radiata tracheary element (TE) system as an experimental platform, we investigated whether metabolic engineering can be used to create syringyl lignin in conifers. Pyrolysis-GC/MS and 2D-NMR analysis of P. radiata TE cultures transformed to express ferulate 5-hydroxylase (F5H) and caffeic acid O-methyltransferase (COMT) from Liquidambar styraciflua confirmed the production and incorporation of sinapyl alcohol into the lignin polymer. Transformation with F5H was sufficient for the production of syringyl lignin in TEs, but cotransformation with COMT improved its formation. In addition, lower levels of the pathway intermediate 5-hydroxyconiferyl alcohol were evidenced in cotransformation experiments, indicating that the introduction of the COMT overcame the inefficiency of the native pine methyltransferases for supporting sinapyl alcohol production.Our results provide the proof of concept that it is possible to generate a lignin polymer that contains syringyl units in Softwood species such as P. radiata, suggesting that it might be possible to retain the outstanding fiber properties of Softwoods while imbuing them with the lignin characteristics of hardwoods that are more favorable for industrial processing.
Christopher Gaston - One of the best experts on this subject based on the ideXlab platform.
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a trade flow analysis of the global Softwood log market implications of russian log export tax reduction and new zealand log production restriction
Forestry, 2016Co-Authors: Weiyew Chang, Christopher GastonAbstract:This study employs a recursive dynamic spatial partial equilibrium model to investigate the trade flow trends in the global Softwood log market. A baseline forecast from 2012 to 2021 is first projected and then compared with three alternative scenarios: (1) Russia reduces its ad valorem Softwood log export tax to 8 per cent to comply with its World Trade Organization accession agreements; (2) New Zealand experiences no expansion at all of its plantation forest log production due to social and environmental considerations (i.e. increased Maori ownership of forest land and the implementation of emissions trading schemes); and (3) a combination of the proposed policies in Russia and New Zealand mentioned above. The results of the baseline projection demonstrate that Softwood log prices will increase in every region globally and that China will continue to be the world’s largest Softwood log importer. However, Softwood log exports from Russia, the US and Canada are expected to drop significantly as a result of current Russian export restrictions, the recovery of the US housing market and mountain pine beetle infestations in western Canada. A comparison of the simulated scenarios with the baseline projection reveals that reducing the Russian Softwood log export tax will have a greater impact on Softwood log prices and total world trade than restricting log production in New Zealand due to the comparatively large log production capacity in Russia. In any scenario, significant trade flow changes (i.e. trade-offs) in response to the proposed policy changes are observed in China and the major export regions. The results of this study offer insights for forest managers and policy makers to examine the global impacts of potential changes in trade policies and supply constraints in these two important Softwood log supply regions in addition to highlighting China’s role in the world Softwood log market.
Oliver M. Terrett - One of the best experts on this subject based on the ideXlab platform.
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Two Softwood GUX clades are responsible for distinct glucuronic acid patterns on xylan.
2021Co-Authors: Jan J. Lyczakowski, Oliver M. Terrett, Christina Fleischmann, Henry Temple, Glenn Thorlby, Mathias Sorieul, Paul DupreeAbstract:Wood of coniferous (Softwood) trees, is a globally significant carbon sink and an important source of biomass for industrial applications. Despite its importance, very little is known about the genetic basis of Softwood biosynthesis. Glucomannan and xylan are the main hemicelluloses in Softwood secondary cell walls. Xylan interacts with the cellulose fibrils in a two-fold screw configuration. Moreover, we have shown that xylan GUX (GlucUronic acid substitution of Xylan)-dependent branching with glucuronic acid is critical for biomass recalcitrance. Here, we investigated the decoration patterns of xylan by Softwood GUX enzymes. Using in vitro and in planta assays we demonstrate that two distinct clades of conifer GUX enzymes are active glucuronyltransferases. Interestingly, these enzymes have different specific activities, with one adding evenly spaced GlcA branches and the other one being also capable of glucuronidating two consecutive xyloses. Since xylan patterning might modulate xylan-cellulose and xylan-lignin interactions, our result further the understanding of Softwood biosynthesis and can contribute to strategies aimed at modifying Softwood cell wall properties.
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Molecular architecture of Softwood revealed by solid-state NMR
Nature Communications, 2019Co-Authors: Oliver M. Terrett, Jan J. Lyczakowski, W. Trent Franks, Dinu Iuga, Steven P Brown, R. Dupree, Li Yu, Paul DupreeAbstract:Economically important Softwood from conifers is mainly composed of the polysaccharides cellulose, galactoglucomannan and xylan, and the phenolic polymer, lignin. The interactions between these polymers lead to wood mechanical strength and must be overcome in biorefining. Here, we use ^13C multidimensional solid-state NMR to analyse the polymer interactions in never-dried cell walls of the Softwood, spruce. In contrast to some earlier Softwood cell wall models, most of the xylan binds to cellulose in the two-fold screw conformation. Moreover, galactoglucomannan alters its conformation by intimately binding to the surface of cellulose microfibrils in a semi-crystalline fashion. Some galactoglucomannan and xylan bind to the same cellulose microfibrils, and lignin is associated with both of these cellulose-bound polysaccharides. We propose a model of Softwood molecular architecture which explains the origin of the different cellulose environments observed in the NMR experiments. Our model will assist strategies for improving wood usage in a sustainable bioeconomy.Understanding the interactions between the constituents of the cell walls in wood is important for understanding the mechanical properties. Here, the authors report on a solid-state NMR study of never-dried Softwood, noticing differences to previous reports and develop a model of Softwood architecture.
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Molecular architecture of Softwood revealed by solid-state NMR
Nature communications, 2019Co-Authors: Oliver M. Terrett, Jan J. Lyczakowski, W. Trent Franks, Dinu Iuga, Steven P Brown, R. Dupree, Paul DupreeAbstract:Economically important Softwood from conifers is mainly composed of the polysaccharides cellulose, galactoglucomannan and xylan, and the phenolic polymer, lignin. The interactions between these polymers lead to wood mechanical strength and must be overcome in biorefining. Here, we use 13C multidimensional solid-state NMR to analyse the polymer interactions in never-dried cell walls of the Softwood, spruce. In contrast to some earlier Softwood cell wall models, most of the xylan binds to cellulose in the two-fold screw conformation. Moreover, galactoglucomannan alters its conformation by intimately binding to the surface of cellulose microfibrils in a semi-crystalline fashion. Some galactoglucomannan and xylan bind to the same cellulose microfibrils, and lignin is associated with both of these cellulose-bound polysaccharides. We propose a model of Softwood molecular architecture which explains the origin of the different cellulose environments observed in the NMR experiments. Our model will assist strategies for improving wood usage in a sustainable bioeconomy.
W. Trent Franks - One of the best experts on this subject based on the ideXlab platform.
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Molecular architecture of Softwood revealed by solid-state NMR
Nature Communications, 2019Co-Authors: Oliver M. Terrett, Jan J. Lyczakowski, W. Trent Franks, Dinu Iuga, Steven P Brown, R. Dupree, Li Yu, Paul DupreeAbstract:Economically important Softwood from conifers is mainly composed of the polysaccharides cellulose, galactoglucomannan and xylan, and the phenolic polymer, lignin. The interactions between these polymers lead to wood mechanical strength and must be overcome in biorefining. Here, we use ^13C multidimensional solid-state NMR to analyse the polymer interactions in never-dried cell walls of the Softwood, spruce. In contrast to some earlier Softwood cell wall models, most of the xylan binds to cellulose in the two-fold screw conformation. Moreover, galactoglucomannan alters its conformation by intimately binding to the surface of cellulose microfibrils in a semi-crystalline fashion. Some galactoglucomannan and xylan bind to the same cellulose microfibrils, and lignin is associated with both of these cellulose-bound polysaccharides. We propose a model of Softwood molecular architecture which explains the origin of the different cellulose environments observed in the NMR experiments. Our model will assist strategies for improving wood usage in a sustainable bioeconomy.Understanding the interactions between the constituents of the cell walls in wood is important for understanding the mechanical properties. Here, the authors report on a solid-state NMR study of never-dried Softwood, noticing differences to previous reports and develop a model of Softwood architecture.
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Molecular architecture of Softwood revealed by solid-state NMR
Nature communications, 2019Co-Authors: Oliver M. Terrett, Jan J. Lyczakowski, W. Trent Franks, Dinu Iuga, Steven P Brown, R. Dupree, Paul DupreeAbstract:Economically important Softwood from conifers is mainly composed of the polysaccharides cellulose, galactoglucomannan and xylan, and the phenolic polymer, lignin. The interactions between these polymers lead to wood mechanical strength and must be overcome in biorefining. Here, we use 13C multidimensional solid-state NMR to analyse the polymer interactions in never-dried cell walls of the Softwood, spruce. In contrast to some earlier Softwood cell wall models, most of the xylan binds to cellulose in the two-fold screw conformation. Moreover, galactoglucomannan alters its conformation by intimately binding to the surface of cellulose microfibrils in a semi-crystalline fashion. Some galactoglucomannan and xylan bind to the same cellulose microfibrils, and lignin is associated with both of these cellulose-bound polysaccharides. We propose a model of Softwood molecular architecture which explains the origin of the different cellulose environments observed in the NMR experiments. Our model will assist strategies for improving wood usage in a sustainable bioeconomy.
