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Lazarus MD, Gouda‐Vossos A, Ziebell A, Brand G. Fostering uncertainty tolerance in anatomy education: Lessons learned from how humanities, arts and social science (HASS) educators develop learners' uncertainty tolerance. Anat Sci Educ 2023; 16:128-147. [PMID: 35114066 PMCID: PMC10078696 DOI: 10.1002/ase.2174] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 01/24/2022] [Accepted: 01/28/2022] [Indexed: 06/14/2023]
Abstract
Uncertainty tolerance, individuals' perceptions/responses to uncertain stimuli, is increasingly recognized as critical to effective healthcare practice. While the Covid-19 pandemic generated collective uncertainty, healthcare-related uncertainty is omnipresent. Correspondingly, there is increasing focus on uncertainty tolerance as a health professional graduate "competency," and a concomitant interest in identifying pedagogy fostering learners' uncertainty tolerance. Despite these calls, practical guidelines for educators are lacking. There is some initial evidence that anatomy education can foster medical students' uncertainty tolerance (e.g., anatomical variation and dissection novelty), however, there remains a knowledge gap regarding robust curriculum-wide uncertainty tolerance teaching strategies. Drawing upon humanities, arts and social sciences (HASS) educators' established uncertainty tolerance pedagogies, this study sought to learn from HASS academics' experiences with, and teaching practices related to, uncertainty pedagogy using a qualitative, exploratory study design. Framework analysis was undertaken using an abductive approach, wherein researchers oscillate between inductive and deductive coding (comparing to the uncertainty tolerance conceptual model). During this analysis, the authors analyzed ~386 min of data from purposively sampled HASS academics' (n = 14) discussions to address the following research questions: (1) What teaching practices do HASS academics' perceive as impacting learners' uncertainty tolerance, and (2) How do HASS academics execute these teaching practices? The results extend current understanding of the moderating effects of education on uncertainty tolerance and supports prior findings that the anatomy learning environment is ripe for supporting learner uncertainty tolerance development. This study adds to growing literature on the powerful moderating effect education has on uncertainty tolerance and proposes translation of HASS uncertainty tolerance teaching practices to enhance anatomy education.
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Affiliation(s)
- Michelle D. Lazarus
- Centre for Human Anatomy EducationDepartment of Anatomy and Developmental BiologyFaculty of Medicine, Nursing and Health SciencesMonash UniversityClaytonVictoriaAustralia
- Monash Centre for Scholarship in Health Education, Faculty of Medicine, Nursing and Health SciencesMonash UniversityClaytonVictoriaAustralia
| | - Amany Gouda‐Vossos
- Centre for Human Anatomy EducationDepartment of Anatomy and Developmental BiologyFaculty of Medicine, Nursing and Health SciencesMonash UniversityClaytonVictoriaAustralia
| | - Angela Ziebell
- School of Life and Environmental SciencesDeakin University Burwood CampusBurwoodVictoriaAustralia
| | - Gabrielle Brand
- Monash Centre for Scholarship in Health Education, Faculty of Medicine, Nursing and Health SciencesMonash UniversityClaytonVictoriaAustralia
- School of Nursing and MidwiferyFaculty of Medicine, Nursing and Health SciencesMonash UniversityFrankstonVictoriaAustralia
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Biswal AK, Atmodjo MA, Pattathil S, Amos RA, Yang X, Winkeler K, Collins C, Mohanty SS, Ryno D, Tan L, Gelineo-Albersheim I, Hunt K, Sykes RW, Turner GB, Ziebell A, Davis MF, Decker SR, Hahn MG, Mohnen D. Working towards recalcitrance mechanisms: increased xylan and homogalacturonan production by overexpression of GAlactUronosylTransferase12 ( GAUT12) causes increased recalcitrance and decreased growth in Populus. Biotechnol Biofuels 2018; 11:9. [PMID: 29371885 PMCID: PMC5771077 DOI: 10.1186/s13068-017-1002-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 12/18/2017] [Indexed: 05/03/2023]
Abstract
BACKGROUND The development of fast-growing hardwood trees as a source of lignocellulosic biomass for biofuel and biomaterial production requires a thorough understanding of the plant cell wall structure and function that underlie the inherent recalcitrance properties of woody biomass. Downregulation of GAUT12.1 in Populus deltoides was recently reported to result in improved biomass saccharification, plant growth, and biomass yield. To further understand GAUT12.1 function in biomass recalcitrance and plant growth, here we report the effects of P. trichocarpa GAUT12.1 overexpression in P. deltoides. RESULTS Increasing GAUT12.1 transcript expression by 7-49% in P. deltoides PtGAUT12.1-overexpression (OE) lines resulted in a nearly complete opposite biomass saccharification and plant growth phenotype to that observed previously in PdGAUT12.1-knockdown (KD) lines. This included significantly reduced glucose, xylose, and total sugar release (12-13%), plant height (6-54%), stem diameter (8-40%), and overall total aerial biomass yield (48-61%) in 3-month-old, greenhouse-grown PtGAUT12.1-OE lines compared to controls. Total lignin content was unaffected by the gene overexpression. Importantly, selected PtGAUT12.1-OE lines retained the recalcitrance and growth phenotypes upon growth for 9 months in the greenhouse and 2.8 years in the field. PtGAUT12.1-OE plants had significantly smaller leaves with lower relative water content, and significantly reduced stem wood xylem cell numbers and size. At the cell wall level, xylose and galacturonic acid contents increased markedly in total cell walls as well as in soluble and insoluble cell wall extracts, consistent with increased amounts of xylan and homogalacturonan in the PtGAUT12.1-OE lines. This led to increased cell wall recalcitrance, as manifested by the 9-15% reduced amounts of recovered extractable wall materials and 8-15% greater amounts of final insoluble pellet in the PtGAUT12.1-OE lines compared to controls. CONCLUSIONS The combined phenotype and chemotype data from P. deltoides PtGAUT12.1-OE and PdGAUT12.1-KD transgenics clearly establish GAUT12.1 as a recalcitrance- and growth-associated gene in poplar. Overall, the data support the hypothesis that GAUT12.1 synthesizes either an HG-containing primer for xylan synthesis or an HG glycan required for proper xylan deposition, anchoring, and/or architecture in the wall, and the possibility of HG and xylan glycans being connected to each other by a base-sensitive covalent linkage.
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Affiliation(s)
- Ajaya K. Biswal
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602 USA
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Rd., Athens, GA 30602-4712 USA
- DOE-BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Melani A. Atmodjo
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602 USA
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Rd., Athens, GA 30602-4712 USA
- DOE-BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Sivakumar Pattathil
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Rd., Athens, GA 30602-4712 USA
- DOE-BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Present Address: Mascoma LLC (Lallemand Inc.), 67 Etna Rd., Lebanon, NH 03766 USA
| | - Robert A. Amos
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602 USA
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Rd., Athens, GA 30602-4712 USA
- DOE-BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Xiaohan Yang
- DOE-BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Bioscience Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Kim Winkeler
- DOE-BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- ArborGen, Inc., 2011 Broadbank Ct., Ridgeville, SC 29472 USA
| | - Cassandra Collins
- DOE-BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- ArborGen, Inc., 2011 Broadbank Ct., Ridgeville, SC 29472 USA
| | - Sushree S. Mohanty
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Rd., Athens, GA 30602-4712 USA
- DOE-BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - David Ryno
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Rd., Athens, GA 30602-4712 USA
- DOE-BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Li Tan
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602 USA
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Rd., Athens, GA 30602-4712 USA
- DOE-BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Ivana Gelineo-Albersheim
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Rd., Athens, GA 30602-4712 USA
- DOE-BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Kimberly Hunt
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Rd., Athens, GA 30602-4712 USA
- DOE-BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Present Address: South Georgia State College, 100 West College Park Dr., Douglas, GA 31533 USA
| | - Robert W. Sykes
- DOE-BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- National Renewable Energy Laboratory, Golden, CO 80401-3305 USA
- Present Address: Nuclear Materials Science, Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87545-1663 USA
| | - Geoffrey B. Turner
- DOE-BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- National Renewable Energy Laboratory, Golden, CO 80401-3305 USA
- Present Address: Nu Mark LLC, 6601 W. Broad St., Richmond, VA 23230 USA
| | - Angela Ziebell
- DOE-BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- National Renewable Energy Laboratory, Golden, CO 80401-3305 USA
| | - Mark F. Davis
- DOE-BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- National Renewable Energy Laboratory, Golden, CO 80401-3305 USA
| | - Stephen R. Decker
- DOE-BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- National Renewable Energy Laboratory, Golden, CO 80401-3305 USA
| | - Michael G. Hahn
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602 USA
- Department of Plant Biology, University of Georgia, Athens, GA 30602 USA
- DOE-BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Debra Mohnen
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602 USA
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Rd., Athens, GA 30602-4712 USA
- DOE-BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
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Wuddineh WA, Mazarei M, Zhang J, Poovaiah CR, Mann DGJ, Ziebell A, Sykes RW, Davis MF, Udvardi MK, Stewart CN. Identification and overexpression of gibberellin 2-oxidase (GA2ox) in switchgrass (Panicum virgatum L.) for improved plant architecture and reduced biomass recalcitrance. Plant Biotechnol J 2015; 13:636-47. [PMID: 25400275 DOI: 10.1111/pbi.12287] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Revised: 09/19/2014] [Accepted: 10/01/2014] [Indexed: 05/18/2023]
Abstract
Gibberellin 2-oxidases (GA2oxs) are a group of 2-oxoglutarate-dependent dioxygenases that catalyse the deactivation of bioactive GA or its precursors through 2β-hydroxylation reaction. In this study, putatively novel switchgrass C20 GA2ox genes were identified with the aim of genetically engineering switchgrass for improved architecture and reduced biomass recalcitrance for biofuel. Three C20 GA2ox genes showed differential regulation patterns among tissues including roots, seedlings and reproductive parts. Using a transgenic approach, we showed that overexpression of two C20 GA2ox genes, that is PvGA2ox5 and PvGA2ox9, resulted in characteristic GA-deficient phenotypes with dark-green leaves and modified plant architecture. The changes in plant morphology appeared to be associated with GA2ox transcript abundance. Exogenous application of GA rescued the GA-deficient phenotypes in transgenic lines. Transgenic semi-dwarf lines displayed increased tillering and reduced lignin content, and the syringyl/guaiacyl lignin monomer ratio accompanied by the reduced expression of lignin biosynthetic genes compared to nontransgenic plants. A moderate increase in the level of glucose release in these transgenic lines might be attributed to reduced biomass recalcitrance as a result of reduced lignin content and lignin composition. Our results suggest that overexpression of GA2ox genes in switchgrass is a feasible strategy to improve plant architecture and reduce biomass recalcitrance for biofuel.
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Affiliation(s)
- Wegi A Wuddineh
- Department of Plant Sciences, University of Tennessee, Knoxville, TN 37996, USA
- Bioenergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Mitra Mazarei
- Department of Plant Sciences, University of Tennessee, Knoxville, TN 37996, USA
- Bioenergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Jiyi Zhang
- Bioenergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- Plant Biology Division, Samuel Roberts Noble Foundation, Ardmore, OK 73401, USA
| | - Charleson R Poovaiah
- Department of Plant Sciences, University of Tennessee, Knoxville, TN 37996, USA
- Bioenergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - David G J Mann
- Department of Plant Sciences, University of Tennessee, Knoxville, TN 37996, USA
- Bioenergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Angela Ziebell
- Bioenergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- National Renewable Energy Laboratory, Golden, CO 80401, USA
| | - Robert W Sykes
- Bioenergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- National Renewable Energy Laboratory, Golden, CO 80401, USA
| | - Mark F Davis
- Bioenergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- National Renewable Energy Laboratory, Golden, CO 80401, USA
| | - Michael K Udvardi
- Bioenergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- Plant Biology Division, Samuel Roberts Noble Foundation, Ardmore, OK 73401, USA
| | - Charles Neal Stewart
- Department of Plant Sciences, University of Tennessee, Knoxville, TN 37996, USA
- Bioenergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
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4
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Muchero W, Guo J, DiFazio SP, Chen JG, Ranjan P, Slavov GT, Gunter LE, Jawdy S, Bryan AC, Sykes R, Ziebell A, Klápště J, Porth I, Skyba O, Unda F, El-Kassaby YA, Douglas CJ, Mansfield SD, Martin J, Schackwitz W, Evans LM, Czarnecki O, Tuskan GA. High-resolution genetic mapping of allelic variants associated with cell wall chemistry in Populus. BMC Genomics 2015; 16:24. [PMID: 25613058 PMCID: PMC4307895 DOI: 10.1186/s12864-015-1215-z] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2014] [Accepted: 01/02/2015] [Indexed: 11/13/2022] Open
Abstract
Background QTL cloning for the discovery of genes underlying polygenic traits has historically been cumbersome in long-lived perennial plants like Populus. Linkage disequilibrium-based association mapping has been proposed as a cloning tool, and recent advances in high-throughput genotyping and whole-genome resequencing enable marker saturation to levels sufficient for association mapping with no a priori candidate gene selection. Here, multiyear and multienvironment evaluation of cell wall phenotypes was conducted in an interspecific P. trichocarpa x P. deltoides pseudo-backcross mapping pedigree and two partially overlapping populations of unrelated P. trichocarpa genotypes using pyrolysis molecular beam mass spectrometry, saccharification, and/ or traditional wet chemistry. QTL mapping was conducted using a high-density genetic map with 3,568 SNP markers. As a fine-mapping approach, chromosome-wide association mapping targeting a QTL hot-spot on linkage group XIV was performed in the two P. trichocarpa populations. Both populations were genotyped using the 34 K Populus Infinium SNP array and whole-genome resequencing of one of the populations facilitated marker-saturation of candidate intervals for gene identification. Results Five QTLs ranging in size from 0.6 to 1.8 Mb were mapped on linkage group XIV for lignin content, syringyl to guaiacyl (S/G) ratio, 5- and 6-carbon sugars using the mapping pedigree. Six candidate loci exhibiting significant associations with phenotypes were identified within QTL intervals. These associations were reproducible across multiple environments, two independent genotyping platforms, and different plant growth stages. cDNA sequencing for allelic variants of three of the six loci identified polymorphisms leading to variable length poly glutamine (PolyQ) stretch in a transcription factor annotated as an ANGUSTIFOLIA C-terminus Binding Protein (CtBP) and premature stop codons in a KANADI transcription factor as well as a protein kinase. Results from protoplast transient expression assays suggested that each of the polymorphisms conferred allelic differences in the activation of cellulose, hemicelluloses, and lignin pathway marker genes. Conclusion This study illustrates the utility of complementary QTL and association mapping as tools for gene discovery with no a priori candidate gene selection. This proof of concept in a perennial organism opens up opportunities for discovery of novel genetic determinants of economically important but complex traits in plants. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1215-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Wellington Muchero
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
| | - Jianjun Guo
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA. .,Current address: Department of Plant Biology, Carnegie Institute for Science, Stanford, CA, 94305, USA.
| | - Stephen P DiFazio
- Department of Biology, West Virginia University, Morgantown, WV, 26506, USA.
| | - Jin-Gui Chen
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
| | - Priya Ranjan
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
| | - Gancho T Slavov
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, SY23 3EB, UK.
| | - Lee E Gunter
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
| | - Sara Jawdy
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
| | - Anthony C Bryan
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
| | - Robert Sykes
- Bioscience Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401, USA.
| | - Angela Ziebell
- Bioscience Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401, USA.
| | - Jaroslav Klápště
- Department of Forest and Conservation Sciences, Faculty of Forestry, University of British Columbia, Forest Sciences Centre, 2424 Main Mall, Vancouver, BC, V6T 1Z4, Canada. .,Department of Genetics and Physiology of Forest Trees, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences in Prague, Kamýcká 129, 165 21, Praha 6, Czech Republic.
| | - Ilga Porth
- Department of Forest and Conservation Sciences, Faculty of Forestry, University of British Columbia, Forest Sciences Centre, 2424 Main Mall, Vancouver, BC, V6T 1Z4, Canada.
| | - Oleksandr Skyba
- Department of Wood Science, Faculty of Forestry, University of British Columbia, Forest Sciences Centre, 2424 Main Mall, Vancouver, BC, V6T 1Z4, Canada.
| | - Faride Unda
- Department of Wood Science, Faculty of Forestry, University of British Columbia, Forest Sciences Centre, 2424 Main Mall, Vancouver, BC, V6T 1Z4, Canada.
| | - Yousry A El-Kassaby
- Department of Forest and Conservation Sciences, Faculty of Forestry, University of British Columbia, Forest Sciences Centre, 2424 Main Mall, Vancouver, BC, V6T 1Z4, Canada.
| | - Carl J Douglas
- Department of Botany, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.
| | - Shawn D Mansfield
- Department of Wood Science, Faculty of Forestry, University of British Columbia, Forest Sciences Centre, 2424 Main Mall, Vancouver, BC, V6T 1Z4, Canada.
| | - Joel Martin
- U.S. Department of Energy Joint Genome Institute, Walnut Creek, CA, 94598, USA.
| | - Wendy Schackwitz
- U.S. Department of Energy Joint Genome Institute, Walnut Creek, CA, 94598, USA.
| | - Luke M Evans
- Department of Biology, West Virginia University, Morgantown, WV, 26506, USA.
| | - Olaf Czarnecki
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
| | - Gerald A Tuskan
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
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5
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Biswal AK, Hao Z, Pattathil S, Yang X, Winkeler K, Collins C, Mohanty SS, Richardson EA, Gelineo-Albersheim I, Hunt K, Ryno D, Sykes RW, Turner GB, Ziebell A, Gjersing E, Lukowitz W, Davis MF, Decker SR, Hahn MG, Mohnen D. Downregulation of GAUT12 in Populus deltoides by RNA silencing results in reduced recalcitrance, increased growth and reduced xylan and pectin in a woody biofuel feedstock. Biotechnol Biofuels 2015; 8:41. [PMID: 25802552 PMCID: PMC4369864 DOI: 10.1186/s13068-015-0218-y] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 02/03/2015] [Indexed: 05/17/2023]
Abstract
BACKGROUND The inherent recalcitrance of woody bioenergy feedstocks is a major challenge for their use as a source of second-generation biofuel. Secondary cell walls that constitute the majority of hardwood biomass are rich in cellulose, xylan, and lignin. The interactions among these polymers prevent facile accessibility and deconstruction by enzymes and chemicals. Plant biomass that can with minimal pretreatment be degraded into sugars is required to produce renewable biofuels in a cost-effective manner. RESULTS GAUT12/IRX8 is a putative glycosyltransferase proposed to be involved in secondary cell wall glucuronoxylan and/or pectin biosynthesis based on concomitant reductions of both xylan and the pectin homogalacturonan (HG) in Arabidopsis irx8 mutants. Two GAUT12 homologs exist in Populus trichocarpa, PtGAUT12.1 and PtGAUT12.2. Knockdown expression of both genes simultaneously has been shown to reduce xylan content in Populus wood. We tested the proposition that RNA interference (RNAi) downregulation of GAUT12.1 alone would lead to increased sugar release in Populus wood, that is, reduced recalcitrance, based on the hypothesis that GAUT12 synthesizes a wall structure required for deposition of xylan and that cell walls with less xylan and/or modified cell wall architecture would have reduced recalcitrance. Using an RNAi approach, we generated 11 Populus deltoides transgenic lines with 50 to 67% reduced PdGAUT12.1 transcript expression compared to wild type (WT) and vector controls. Ten of the eleven RNAi lines yielded 4 to 8% greater glucose release upon enzymatic saccharification than the controls. The PdGAUT12.1 knockdown (PdGAUT12.1-KD) lines also displayed 12 to 52% and 12 to 44% increased plant height and radial stem diameter, respectively, compared to the controls. Knockdown of PdGAUT12.1 resulted in a 25 to 47% reduction in galacturonic acid and 17 to 30% reduction in xylose without affecting total lignin content, revealing that in Populus wood as in Arabidopsis, GAUT12 affects both pectin and xylan formation. Analyses of the sugars present in sequential cell wall extracts revealed a reduction of glucuronoxylan and pectic HG and rhamnogalacturonan in extracts from PdGAUT12.1-KD lines. CONCLUSIONS The results show that downregulation of GAUT12.1 leads to a reduction in a population of xylan and pectin during wood formation and to reduced recalcitrance, more easily extractable cell walls, and increased growth in Populus.
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Affiliation(s)
- Ajaya K Biswal
- />Department of Biochemistry and Molecular Biology, University of Georgia, B122 Life Sciences Bldg., Athens, GA 30602 USA
- />Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602 USA
- />DOE-BioEnergy Science Center (BESC), Oak Ridge, USA
| | - Zhangying Hao
- />Department of Plant Biology, University of Georgia, 2502 Miller Plant Sciences, Athens, GA 30602 USA
- />Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602 USA
- />DOE-BioEnergy Science Center (BESC), Oak Ridge, USA
| | - Sivakumar Pattathil
- />Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602 USA
- />DOE-BioEnergy Science Center (BESC), Oak Ridge, USA
| | - Xiaohan Yang
- />DOE-BioEnergy Science Center (BESC), Oak Ridge, USA
- />Bioscience Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Kim Winkeler
- />DOE-BioEnergy Science Center (BESC), Oak Ridge, USA
- />ArborGen Inc., 2011 Broadbank Ct, Ridgeville, SC 29472 USA
| | - Cassandra Collins
- />DOE-BioEnergy Science Center (BESC), Oak Ridge, USA
- />ArborGen Inc., 2011 Broadbank Ct, Ridgeville, SC 29472 USA
| | - Sushree S Mohanty
- />Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602 USA
- />DOE-BioEnergy Science Center (BESC), Oak Ridge, USA
| | - Elizabeth A Richardson
- />Department of Plant Biology, University of Georgia, 2502 Miller Plant Sciences, Athens, GA 30602 USA
| | - Ivana Gelineo-Albersheim
- />Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602 USA
- />DOE-BioEnergy Science Center (BESC), Oak Ridge, USA
| | - Kimberly Hunt
- />Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602 USA
- />DOE-BioEnergy Science Center (BESC), Oak Ridge, USA
| | - David Ryno
- />Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602 USA
- />DOE-BioEnergy Science Center (BESC), Oak Ridge, USA
| | - Robert W Sykes
- />DOE-BioEnergy Science Center (BESC), Oak Ridge, USA
- />National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401-3305 USA
| | - Geoffrey B Turner
- />DOE-BioEnergy Science Center (BESC), Oak Ridge, USA
- />National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401-3305 USA
| | - Angela Ziebell
- />DOE-BioEnergy Science Center (BESC), Oak Ridge, USA
- />National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401-3305 USA
| | - Erica Gjersing
- />DOE-BioEnergy Science Center (BESC), Oak Ridge, USA
- />National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401-3305 USA
| | - Wolfgang Lukowitz
- />Department of Plant Biology, University of Georgia, 2502 Miller Plant Sciences, Athens, GA 30602 USA
| | - Mark F Davis
- />DOE-BioEnergy Science Center (BESC), Oak Ridge, USA
- />National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401-3305 USA
| | - Stephen R Decker
- />DOE-BioEnergy Science Center (BESC), Oak Ridge, USA
- />National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401-3305 USA
| | - Michael G Hahn
- />Department of Plant Biology, University of Georgia, 2502 Miller Plant Sciences, Athens, GA 30602 USA
- />Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602 USA
- />DOE-BioEnergy Science Center (BESC), Oak Ridge, USA
| | - Debra Mohnen
- />Department of Biochemistry and Molecular Biology, University of Georgia, B122 Life Sciences Bldg., Athens, GA 30602 USA
- />Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602 USA
- />DOE-BioEnergy Science Center (BESC), Oak Ridge, USA
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Sykes RW, Gjersing EL, Foutz K, Rottmann WH, Kuhn SA, Foster CE, Ziebell A, Turner GB, Decker SR, Hinchee MAW, Davis MF. Down-regulation of p-coumaroyl quinate/shikimate 3'-hydroxylase (C3'H) and cinnamate 4-hydroxylase (C4H) genes in the lignin biosynthetic pathway of Eucalyptus urophylla × E. grandis leads to improved sugar release. Biotechnol Biofuels 2015; 8:128. [PMID: 26312068 PMCID: PMC4550073 DOI: 10.1186/s13068-015-0316-x] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 08/13/2015] [Indexed: 05/02/2023]
Abstract
BACKGROUND Lignocellulosic materials provide an attractive replacement for food-based crops used to produce ethanol. Understanding the interactions within the cell wall is vital to overcome the highly recalcitrant nature of biomass. One factor imparting plant cell wall recalcitrance is lignin, which can be manipulated by making changes in the lignin biosynthetic pathway. In this study, eucalyptus down-regulated in expression of cinnamate 4-hydroxylase (C4H, EC 1.14.13.11) or p-coumaroyl quinate/shikimate 3'-hydroxylase (C3'H, EC 1.14.13.36) were evaluated for cell wall composition and reduced recalcitrance. RESULTS Eucalyptus trees with down-regulated C4H or C3'H expression displayed lowered overall lignin content. The control samples had an average of 29.6 %, the C3'H reduced lines had an average of 21.7 %, and the C4H reduced lines had an average of 18.9 % lignin from wet chemical analysis. The C3'H and C4H down-regulated lines had different lignin compositions with average S/G/H ratios of 48.5/33.2/18.3 for the C3'H reduced lines and 59.0/39.8/1.2 for the C4H reduced lines, compared to the control with 65.9/33.2/1.0. Both the C4H and C3'H down-regulated lines had reduced recalcitrance as indicated by increased sugar release as determined using enzymatic conversion assays utilizing both no pretreatment and a hot water pretreatment. CONCLUSIONS Lowering lignin content rather than altering sinapyl alcohol/coniferyl alcohol/4-coumaryl alcohol ratios was found to have the largest impact on reducing recalcitrance of the transgenic eucalyptus variants. The development of lower recalcitrance trees opens up the possibility of using alternative pretreatment strategies in biomass conversion processes that can reduce processing costs.
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Affiliation(s)
- Robert W. Sykes
- />National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401-3393 USA
| | - Erica L. Gjersing
- />National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401-3393 USA
| | - Kirk Foutz
- />ArborGen Inc., 2011 Broadbank Ct., Ridgeville, SC 29472 USA
| | | | - Sean A. Kuhn
- />ArborGen Inc., 2011 Broadbank Ct., Ridgeville, SC 29472 USA
| | - Cliff E. Foster
- />Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI 48824 USA
| | - Angela Ziebell
- />National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401-3393 USA
| | - Geoffrey B. Turner
- />Biosciences Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401-3393 USA
| | - Stephen R. Decker
- />Biosciences Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401-3393 USA
| | | | - Mark F. Davis
- />National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401-3393 USA
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7
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Baxter HL, Mazarei M, Labbe N, Kline LM, Cheng Q, Windham MT, Mann DGJ, Fu C, Ziebell A, Sykes RW, Rodriguez M, Davis MF, Mielenz JR, Dixon RA, Wang ZY, Stewart CN. Two-year field analysis of reduced recalcitrance transgenic switchgrass. Plant Biotechnol J 2014; 12:914-24. [PMID: 24751162 DOI: 10.1111/pbi.12195] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Accepted: 03/18/2014] [Indexed: 05/03/2023]
Abstract
Switchgrass (Panicum virgatum L.) is a leading candidate for a dedicated lignocellulosic biofuel feedstock owing to its high biomass production, wide adaptation and low agronomic input requirements. Lignin in cell walls of switchgrass, and other lignocellulosic feedstocks, severely limits the accessibility of cell wall carbohydrates to enzymatic breakdown into fermentable sugars and subsequently biofuels. Low-lignin transgenic switchgrass plants produced by the down-regulation of caffeic acid O-methyltransferase (COMT), a lignin biosynthetic enzyme, were analysed in the field for two growing seasons. COMT transcript abundance, lignin content and the syringyl/guaiacyl lignin monomer ratio were consistently lower in the COMT-down-regulated plants throughout the duration of the field trial. In general, analyses with fully established plants harvested during the second growing season produced results that were similar to those observed in previous greenhouse studies with these plants. Sugar release was improved by up to 34% and ethanol yield by up to 28% in the transgenic lines relative to controls. Additionally, these results were obtained using senesced plant material harvested at the end of the growing season, compared with the young, green tissue that was used in the greenhouse experiments. Another important finding was that transgenic plants were not more susceptible to rust (Puccinia emaculata). The results of this study suggest that lignin down-regulation in switchgrass can confer real-world improvements in biofuel yield without negative consequences to biomass yield or disease susceptibility.
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Affiliation(s)
- Holly L Baxter
- Department of Plant Sciences, University of Tennessee, Knoxville, TN, 37996, USA; BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
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8
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Penning BW, Sykes RW, Babcock NC, Dugard CK, Held MA, Klimek JF, Shreve JT, Fowler M, Ziebell A, Davis MF, Decker SR, Turner GB, Mosier NS, Springer NM, Thimmapuram J, Weil CF, McCann MC, Carpita NC. Genetic Determinants for Enzymatic Digestion of Lignocellulosic Biomass Are Independent of Those for Lignin Abundance in a Maize Recombinant Inbred Population. Plant Physiol 2014; 165:1475-1487. [PMID: 24972714 PMCID: PMC4119032 DOI: 10.1104/pp.114.242446] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Biotechnological approaches to reduce or modify lignin in biomass crops are predicated on the assumption that it is the principal determinant of the recalcitrance of biomass to enzymatic digestion for biofuels production. We defined quantitative trait loci (QTL) in the Intermated B73 × Mo17 recombinant inbred maize (Zea mays) population using pyrolysis molecular-beam mass spectrometry to establish stem lignin content and an enzymatic hydrolysis assay to measure glucose and xylose yield. Among five multiyear QTL for lignin abundance, two for 4-vinylphenol abundance, and four for glucose and/or xylose yield, not a single QTL for aromatic abundance and sugar yield was shared. A genome-wide association study for lignin abundance and sugar yield of the 282-member maize association panel provided candidate genes in the 11 QTL of the B73 and Mo17 parents but showed that many other alleles impacting these traits exist among this broader pool of maize genetic diversity. B73 and Mo17 genotypes exhibited large differences in gene expression in developing stem tissues independent of allelic variation. Combining these complementary genetic approaches provides a narrowed list of candidate genes. A cluster of SCARECROW-LIKE9 and SCARECROW-LIKE14 transcription factor genes provides exceptionally strong candidate genes emerging from the genome-wide association study. In addition to these and genes associated with cell wall metabolism, candidates include several other transcription factors associated with vascularization and fiber formation and components of cellular signaling pathways. These results provide new insights and strategies beyond the modification of lignin to enhance yields of biofuels from genetically modified biomass.
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Affiliation(s)
- Bryan W Penning
- Departments of Biological Sciences (B.W.P., M.C.M., N.C.C.), Botany and Plant Pathology (C.K.D., M.A.H., J.F.K., N.C.C.), and Agronomy (N.C.B., C.F.W.), Laboratory of Renewable Resources Engineering and Agricultural and Biological Engineering (N.S.M.), and Bioinformatics Core (J.T.S., J.T.), Purdue University, West Lafayette, Indiana 47907;National Bioenergy Center, National Renewable Energy Laboratory, Golden, Colorado 80401 (R.W.S., M.F., A.Z., M.F.D., S.R.D., G.B.T.); andDepartment of Plant Biology, University of Minnesota, St. Paul, Minnesota 55108 (N.M.S.)
| | - Robert W Sykes
- Departments of Biological Sciences (B.W.P., M.C.M., N.C.C.), Botany and Plant Pathology (C.K.D., M.A.H., J.F.K., N.C.C.), and Agronomy (N.C.B., C.F.W.), Laboratory of Renewable Resources Engineering and Agricultural and Biological Engineering (N.S.M.), and Bioinformatics Core (J.T.S., J.T.), Purdue University, West Lafayette, Indiana 47907;National Bioenergy Center, National Renewable Energy Laboratory, Golden, Colorado 80401 (R.W.S., M.F., A.Z., M.F.D., S.R.D., G.B.T.); andDepartment of Plant Biology, University of Minnesota, St. Paul, Minnesota 55108 (N.M.S.)
| | - Nicholas C Babcock
- Departments of Biological Sciences (B.W.P., M.C.M., N.C.C.), Botany and Plant Pathology (C.K.D., M.A.H., J.F.K., N.C.C.), and Agronomy (N.C.B., C.F.W.), Laboratory of Renewable Resources Engineering and Agricultural and Biological Engineering (N.S.M.), and Bioinformatics Core (J.T.S., J.T.), Purdue University, West Lafayette, Indiana 47907;National Bioenergy Center, National Renewable Energy Laboratory, Golden, Colorado 80401 (R.W.S., M.F., A.Z., M.F.D., S.R.D., G.B.T.); andDepartment of Plant Biology, University of Minnesota, St. Paul, Minnesota 55108 (N.M.S.)
| | - Christopher K Dugard
- Departments of Biological Sciences (B.W.P., M.C.M., N.C.C.), Botany and Plant Pathology (C.K.D., M.A.H., J.F.K., N.C.C.), and Agronomy (N.C.B., C.F.W.), Laboratory of Renewable Resources Engineering and Agricultural and Biological Engineering (N.S.M.), and Bioinformatics Core (J.T.S., J.T.), Purdue University, West Lafayette, Indiana 47907;National Bioenergy Center, National Renewable Energy Laboratory, Golden, Colorado 80401 (R.W.S., M.F., A.Z., M.F.D., S.R.D., G.B.T.); andDepartment of Plant Biology, University of Minnesota, St. Paul, Minnesota 55108 (N.M.S.)
| | - Michael A Held
- Departments of Biological Sciences (B.W.P., M.C.M., N.C.C.), Botany and Plant Pathology (C.K.D., M.A.H., J.F.K., N.C.C.), and Agronomy (N.C.B., C.F.W.), Laboratory of Renewable Resources Engineering and Agricultural and Biological Engineering (N.S.M.), and Bioinformatics Core (J.T.S., J.T.), Purdue University, West Lafayette, Indiana 47907;National Bioenergy Center, National Renewable Energy Laboratory, Golden, Colorado 80401 (R.W.S., M.F., A.Z., M.F.D., S.R.D., G.B.T.); andDepartment of Plant Biology, University of Minnesota, St. Paul, Minnesota 55108 (N.M.S.)
| | - John F Klimek
- Departments of Biological Sciences (B.W.P., M.C.M., N.C.C.), Botany and Plant Pathology (C.K.D., M.A.H., J.F.K., N.C.C.), and Agronomy (N.C.B., C.F.W.), Laboratory of Renewable Resources Engineering and Agricultural and Biological Engineering (N.S.M.), and Bioinformatics Core (J.T.S., J.T.), Purdue University, West Lafayette, Indiana 47907;National Bioenergy Center, National Renewable Energy Laboratory, Golden, Colorado 80401 (R.W.S., M.F., A.Z., M.F.D., S.R.D., G.B.T.); andDepartment of Plant Biology, University of Minnesota, St. Paul, Minnesota 55108 (N.M.S.)
| | - Jacob T Shreve
- Departments of Biological Sciences (B.W.P., M.C.M., N.C.C.), Botany and Plant Pathology (C.K.D., M.A.H., J.F.K., N.C.C.), and Agronomy (N.C.B., C.F.W.), Laboratory of Renewable Resources Engineering and Agricultural and Biological Engineering (N.S.M.), and Bioinformatics Core (J.T.S., J.T.), Purdue University, West Lafayette, Indiana 47907;National Bioenergy Center, National Renewable Energy Laboratory, Golden, Colorado 80401 (R.W.S., M.F., A.Z., M.F.D., S.R.D., G.B.T.); andDepartment of Plant Biology, University of Minnesota, St. Paul, Minnesota 55108 (N.M.S.)
| | - Matthew Fowler
- Departments of Biological Sciences (B.W.P., M.C.M., N.C.C.), Botany and Plant Pathology (C.K.D., M.A.H., J.F.K., N.C.C.), and Agronomy (N.C.B., C.F.W.), Laboratory of Renewable Resources Engineering and Agricultural and Biological Engineering (N.S.M.), and Bioinformatics Core (J.T.S., J.T.), Purdue University, West Lafayette, Indiana 47907;National Bioenergy Center, National Renewable Energy Laboratory, Golden, Colorado 80401 (R.W.S., M.F., A.Z., M.F.D., S.R.D., G.B.T.); andDepartment of Plant Biology, University of Minnesota, St. Paul, Minnesota 55108 (N.M.S.)
| | - Angela Ziebell
- Departments of Biological Sciences (B.W.P., M.C.M., N.C.C.), Botany and Plant Pathology (C.K.D., M.A.H., J.F.K., N.C.C.), and Agronomy (N.C.B., C.F.W.), Laboratory of Renewable Resources Engineering and Agricultural and Biological Engineering (N.S.M.), and Bioinformatics Core (J.T.S., J.T.), Purdue University, West Lafayette, Indiana 47907;National Bioenergy Center, National Renewable Energy Laboratory, Golden, Colorado 80401 (R.W.S., M.F., A.Z., M.F.D., S.R.D., G.B.T.); andDepartment of Plant Biology, University of Minnesota, St. Paul, Minnesota 55108 (N.M.S.)
| | - Mark F Davis
- Departments of Biological Sciences (B.W.P., M.C.M., N.C.C.), Botany and Plant Pathology (C.K.D., M.A.H., J.F.K., N.C.C.), and Agronomy (N.C.B., C.F.W.), Laboratory of Renewable Resources Engineering and Agricultural and Biological Engineering (N.S.M.), and Bioinformatics Core (J.T.S., J.T.), Purdue University, West Lafayette, Indiana 47907;National Bioenergy Center, National Renewable Energy Laboratory, Golden, Colorado 80401 (R.W.S., M.F., A.Z., M.F.D., S.R.D., G.B.T.); andDepartment of Plant Biology, University of Minnesota, St. Paul, Minnesota 55108 (N.M.S.)
| | - Stephen R Decker
- Departments of Biological Sciences (B.W.P., M.C.M., N.C.C.), Botany and Plant Pathology (C.K.D., M.A.H., J.F.K., N.C.C.), and Agronomy (N.C.B., C.F.W.), Laboratory of Renewable Resources Engineering and Agricultural and Biological Engineering (N.S.M.), and Bioinformatics Core (J.T.S., J.T.), Purdue University, West Lafayette, Indiana 47907;National Bioenergy Center, National Renewable Energy Laboratory, Golden, Colorado 80401 (R.W.S., M.F., A.Z., M.F.D., S.R.D., G.B.T.); andDepartment of Plant Biology, University of Minnesota, St. Paul, Minnesota 55108 (N.M.S.)
| | - Geoffrey B Turner
- Departments of Biological Sciences (B.W.P., M.C.M., N.C.C.), Botany and Plant Pathology (C.K.D., M.A.H., J.F.K., N.C.C.), and Agronomy (N.C.B., C.F.W.), Laboratory of Renewable Resources Engineering and Agricultural and Biological Engineering (N.S.M.), and Bioinformatics Core (J.T.S., J.T.), Purdue University, West Lafayette, Indiana 47907;National Bioenergy Center, National Renewable Energy Laboratory, Golden, Colorado 80401 (R.W.S., M.F., A.Z., M.F.D., S.R.D., G.B.T.); andDepartment of Plant Biology, University of Minnesota, St. Paul, Minnesota 55108 (N.M.S.)
| | - Nathan S Mosier
- Departments of Biological Sciences (B.W.P., M.C.M., N.C.C.), Botany and Plant Pathology (C.K.D., M.A.H., J.F.K., N.C.C.), and Agronomy (N.C.B., C.F.W.), Laboratory of Renewable Resources Engineering and Agricultural and Biological Engineering (N.S.M.), and Bioinformatics Core (J.T.S., J.T.), Purdue University, West Lafayette, Indiana 47907;National Bioenergy Center, National Renewable Energy Laboratory, Golden, Colorado 80401 (R.W.S., M.F., A.Z., M.F.D., S.R.D., G.B.T.); andDepartment of Plant Biology, University of Minnesota, St. Paul, Minnesota 55108 (N.M.S.)
| | - Nathan M Springer
- Departments of Biological Sciences (B.W.P., M.C.M., N.C.C.), Botany and Plant Pathology (C.K.D., M.A.H., J.F.K., N.C.C.), and Agronomy (N.C.B., C.F.W.), Laboratory of Renewable Resources Engineering and Agricultural and Biological Engineering (N.S.M.), and Bioinformatics Core (J.T.S., J.T.), Purdue University, West Lafayette, Indiana 47907;National Bioenergy Center, National Renewable Energy Laboratory, Golden, Colorado 80401 (R.W.S., M.F., A.Z., M.F.D., S.R.D., G.B.T.); andDepartment of Plant Biology, University of Minnesota, St. Paul, Minnesota 55108 (N.M.S.)
| | - Jyothi Thimmapuram
- Departments of Biological Sciences (B.W.P., M.C.M., N.C.C.), Botany and Plant Pathology (C.K.D., M.A.H., J.F.K., N.C.C.), and Agronomy (N.C.B., C.F.W.), Laboratory of Renewable Resources Engineering and Agricultural and Biological Engineering (N.S.M.), and Bioinformatics Core (J.T.S., J.T.), Purdue University, West Lafayette, Indiana 47907;National Bioenergy Center, National Renewable Energy Laboratory, Golden, Colorado 80401 (R.W.S., M.F., A.Z., M.F.D., S.R.D., G.B.T.); andDepartment of Plant Biology, University of Minnesota, St. Paul, Minnesota 55108 (N.M.S.)
| | - Clifford F Weil
- Departments of Biological Sciences (B.W.P., M.C.M., N.C.C.), Botany and Plant Pathology (C.K.D., M.A.H., J.F.K., N.C.C.), and Agronomy (N.C.B., C.F.W.), Laboratory of Renewable Resources Engineering and Agricultural and Biological Engineering (N.S.M.), and Bioinformatics Core (J.T.S., J.T.), Purdue University, West Lafayette, Indiana 47907;National Bioenergy Center, National Renewable Energy Laboratory, Golden, Colorado 80401 (R.W.S., M.F., A.Z., M.F.D., S.R.D., G.B.T.); andDepartment of Plant Biology, University of Minnesota, St. Paul, Minnesota 55108 (N.M.S.)
| | - Maureen C McCann
- Departments of Biological Sciences (B.W.P., M.C.M., N.C.C.), Botany and Plant Pathology (C.K.D., M.A.H., J.F.K., N.C.C.), and Agronomy (N.C.B., C.F.W.), Laboratory of Renewable Resources Engineering and Agricultural and Biological Engineering (N.S.M.), and Bioinformatics Core (J.T.S., J.T.), Purdue University, West Lafayette, Indiana 47907;National Bioenergy Center, National Renewable Energy Laboratory, Golden, Colorado 80401 (R.W.S., M.F., A.Z., M.F.D., S.R.D., G.B.T.); andDepartment of Plant Biology, University of Minnesota, St. Paul, Minnesota 55108 (N.M.S.)
| | - Nicholas C Carpita
- Departments of Biological Sciences (B.W.P., M.C.M., N.C.C.), Botany and Plant Pathology (C.K.D., M.A.H., J.F.K., N.C.C.), and Agronomy (N.C.B., C.F.W.), Laboratory of Renewable Resources Engineering and Agricultural and Biological Engineering (N.S.M.), and Bioinformatics Core (J.T.S., J.T.), Purdue University, West Lafayette, Indiana 47907;National Bioenergy Center, National Renewable Energy Laboratory, Golden, Colorado 80401 (R.W.S., M.F., A.Z., M.F.D., S.R.D., G.B.T.); andDepartment of Plant Biology, University of Minnesota, St. Paul, Minnesota 55108 (N.M.S.)
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9
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Shen H, Poovaiah CR, Ziebell A, Tschaplinski TJ, Pattathil S, Gjersing E, Engle NL, Katahira R, Pu Y, Sykes R, Chen F, Ragauskas AJ, Mielenz JR, Hahn MG, Davis M, Stewart CN, Dixon RA. Enhanced characteristics of genetically modified switchgrass (Panicum virgatum L.) for high biofuel production. Biotechnol Biofuels 2013; 6:71. [PMID: 23651942 PMCID: PMC3652750 DOI: 10.1186/1754-6834-6-71] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Accepted: 04/30/2013] [Indexed: 05/18/2023]
Abstract
BACKGROUND Lignocellulosic biomass is one of the most promising renewable and clean energy resources to reduce greenhouse gas emissions and dependence on fossil fuels. However, the resistance to accessibility of sugars embedded in plant cell walls (so-called recalcitrance) is a major barrier to economically viable cellulosic ethanol production. A recent report from the US National Academy of Sciences indicated that, "absent technological breakthroughs", it was unlikely that the US would meet the congressionally mandated renewable fuel standard of 35 billion gallons of ethanol-equivalent biofuels plus 1 billion gallons of biodiesel by 2022. We here describe the properties of switchgrass (Panicum virgatum) biomass that has been genetically engineered to increase the cellulosic ethanol yield by more than 2-fold. RESULTS We have increased the cellulosic ethanol yield from switchgrass by 2.6-fold through overexpression of the transcription factor PvMYB4. This strategy reduces carbon deposition into lignin and phenolic fermentation inhibitors while maintaining the availability of potentially fermentable soluble sugars and pectic polysaccharides. Detailed biomass characterization analyses revealed that the levels and nature of phenolic acids embedded in the cell-wall, the lignin content and polymer size, lignin internal linkage levels, linkages between lignin and xylans/pectins, and levels of wall-bound fucose are all altered in PvMYB4-OX lines. Genetically engineered PvMYB4-OX switchgrass therefore provides a novel system for further understanding cell wall recalcitrance. CONCLUSIONS Our results have demonstrated that overexpression of PvMYB4, a general transcriptional repressor of the phenylpropanoid/lignin biosynthesis pathway, can lead to very high yield ethanol production through dramatic reduction of recalcitrance. MYB4-OX switchgrass is an excellent model system for understanding recalcitrance, and provides new germplasm for developing switchgrass cultivars as biomass feedstocks for biofuel production.
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Affiliation(s)
- Hui Shen
- Plant Biology Division, Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, OK, 73401, USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Charleson R Poovaiah
- Department of Plant Sciences, University of Tennessee, 2431 Joe Johnson Dr., Knoxville, TN, 37996, USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Angela Ziebell
- National Renewable Energy Laboratory, 1617 Cole Blvd., Golden, CO, 80401, USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Timothy J Tschaplinski
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Sivakumar Pattathil
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Rd., Athens, GA, 30602, USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Erica Gjersing
- National Renewable Energy Laboratory, 1617 Cole Blvd., Golden, CO, 80401, USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Nancy L Engle
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Rui Katahira
- National Renewable Energy Laboratory, 1617 Cole Blvd., Golden, CO, 80401, USA
- Present address: Department of Biological Sciences, University of North Texas, 1155 Union Circle, Denton, TX 76203, USA
| | - Yunqiao Pu
- National Renewable Energy Laboratory, 1617 Cole Blvd., Golden, CO, 80401, USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Robert Sykes
- National Renewable Energy Laboratory, 1617 Cole Blvd., Golden, CO, 80401, USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Fang Chen
- Plant Biology Division, Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, OK, 73401, USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Arthur J Ragauskas
- School of Chemistry & Biochemistry, Georgia Institute of Technology, 901 Atlantic Drive, 30332, Atlanta, GA, USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Jonathan R Mielenz
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Michael G Hahn
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Rd., Athens, GA, 30602, USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Mark Davis
- National Renewable Energy Laboratory, 1617 Cole Blvd., Golden, CO, 80401, USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - C Neal Stewart
- Department of Plant Sciences, University of Tennessee, 2431 Joe Johnson Dr., Knoxville, TN, 37996, USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Richard A Dixon
- Plant Biology Division, Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, OK, 73401, USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
- Present address: Department of Biological Sciences, University of North Texas, 1155 Union Circle, Denton, TX 76203, USA
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10
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Bartley LE, Peck ML, Kim SR, Ebert B, Manisseri C, Chiniquy DM, Sykes R, Gao L, Rautengarten C, Vega-Sánchez ME, Benke PI, Canlas PE, Cao P, Brewer S, Lin F, Smith WL, Zhang X, Keasling JD, Jentoff RE, Foster SB, Zhou J, Ziebell A, An G, Scheller HV, Ronald PC. Overexpression of a BAHD acyltransferase, OsAt10, alters rice cell wall hydroxycinnamic acid content and saccharification. Plant Physiol 2013; 161:1615-33. [PMID: 23391577 PMCID: PMC3613443 DOI: 10.1104/pp.112.208694] [Citation(s) in RCA: 118] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Grass cell wall properties influence food, feed, and biofuel feedstock usage efficiency. The glucuronoarabinoxylan of grass cell walls is esterified with the phenylpropanoid-derived hydroxycinnamic acids ferulic acid (FA) and para-coumaric acid (p-CA). Feruloyl esters undergo oxidative coupling with neighboring phenylpropanoids on glucuronoarabinoxylan and lignin. Examination of rice (Oryza sativa) mutants in a grass-expanded and -diverged clade of BAHD acyl-coenzyme A-utilizing transferases identified four mutants with altered cell wall FA or p-CA contents. Here, we report on the effects of overexpressing one of these genes, OsAt10 (LOC_Os06g39390), in rice. An activation-tagged line, OsAT10-D1, shows a 60% reduction in matrix polysaccharide-bound FA and an approximately 300% increase in p-CA in young leaf tissue but no discernible phenotypic alterations in vegetative development, lignin content, or lignin composition. Two additional independent OsAt10 overexpression lines show similar changes in FA and p-CA content. Cell wall fractionation and liquid chromatography-mass spectrometry experiments isolate the cell wall alterations in the mutant to ester conjugates of a five-carbon sugar with p-CA and FA. These results suggest that OsAT10 is a p-coumaroyl coenzyme A transferase involved in glucuronoarabinoxylan modification. Biomass from OsAT10-D1 exhibits a 20% to 40% increase in saccharification yield depending on the assay. Thus, OsAt10 is an attractive target for improving grass cell wall quality for fuel and animal feed.
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Affiliation(s)
- Laura E Bartley
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, Oklahoma 73019, USA.
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Sangha AK, Parks JM, Standaert RF, Ziebell A, Davis M, Smith JC. Radical Coupling Reactions in Lignin Synthesis: A Density Functional Theory Study. J Phys Chem B 2012; 116:4760-8. [DOI: 10.1021/jp2122449] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Amandeep K. Sangha
- UT/ORNL Center for
Molecular Biophysics, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6309, United
States
| | - Jerry M. Parks
- UT/ORNL Center for
Molecular Biophysics, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6309, United
States
- Bioenergy Science
Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge,
Tennessee 37831, United States
| | - Robert F. Standaert
- Department of Biochemistry
and
Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996, United States
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge,
Tennessee 37831, United States
- Biology and Soft
Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Angela Ziebell
- Bioenergy Science
Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, Colorado
80401, United States
| | - Mark Davis
- Bioenergy Science
Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, Colorado
80401, United States
| | - Jeremy C. Smith
- UT/ORNL Center for
Molecular Biophysics, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6309, United
States
- Department of Biochemistry
and
Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996, United States
- Bioenergy Science
Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge,
Tennessee 37831, United States
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12
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Ziebell A, Gracom K, Katahira R, Chen F, Pu Y, Ragauskas A, Dixon RA, Davis M. Increase in 4-coumaryl alcohol units during lignification in alfalfa (Medicago sativa) alters the extractability and molecular weight of lignin. J Biol Chem 2010; 285:38961-8. [PMID: 20921228 PMCID: PMC2998124 DOI: 10.1074/jbc.m110.137315] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2010] [Revised: 08/09/2010] [Indexed: 11/06/2022] Open
Abstract
The lignin content of biomass can impact the ease and cost of biomass processing. Lignin reduction through breeding and genetic modification therefore has potential to reduce costs in biomass-processing industries (e.g. pulp and paper, forage, and lignocellulosic ethanol). We investigated compositional changes in two low-lignin alfalfa (Medicago sativa) lines with antisense down-regulation of p-coumarate 3-hydroxylase (C3H) or hydroxycinnamoyl-CoA:shikimate hydroxycinnamoyltransferase (HCT). We investigated whether the difference in reactivity during lignification of 4-coumaryl alcohol (H) monomers versus the naturally dominant sinapyl alcohol and coniferyl alcohol lignin monomers alters the lignin structure. Sequential base extraction readily reduced the H monomer content of the transgenic lines, leaving a residual lignin greatly enriched in H subunits; the extraction profile highlighted the difference between the control and transgenic lines. Gel permeation chromatography of isolated ball-milled lignin indicated significant changes in the weight average molecular weight distribution of the control versus transgenic lines (CTR1a, 6000; C3H4a, 5500; C3H9a, 4000; and HCT30a, 4000).
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Affiliation(s)
- Angela Ziebell
- From the National Bioenergy Center and
- Bioenergy Science Center, National Renewable Energy Laboratory, Golden, Colorado 80401-3393
| | - Kristen Gracom
- From the National Bioenergy Center and
- Bioenergy Science Center, National Renewable Energy Laboratory, Golden, Colorado 80401-3393
| | | | - Fang Chen
- the Samuel Roberts Noble Foundation and
- the Bioenergy Science Center, Ardmore, Oklahoma 73401, and
| | - Yunqiao Pu
- the Institute of Paper Science and Technology and
- Bioenergy Science Center, Georgia Tech, Atlanta, Georgia 30318
| | - Art Ragauskas
- the Institute of Paper Science and Technology and
- Bioenergy Science Center, Georgia Tech, Atlanta, Georgia 30318
| | - Richard A. Dixon
- the Samuel Roberts Noble Foundation and
- the Bioenergy Science Center, Ardmore, Oklahoma 73401, and
| | - Mark Davis
- From the National Bioenergy Center and
- Bioenergy Science Center, National Renewable Energy Laboratory, Golden, Colorado 80401-3393
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13
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Ali A, Altamore TM, Bliese M, Fisara P, Liepa AJ, Meyer AG, Nguyen O, Sargent RM, Sawutz DG, Winkler DA, Winzenberg KN, Ziebell A. Parasiticidal 2-alkoxy- and 2-aryloxyiminoalkyl trifluoromethanesulfonanilides. Bioorg Med Chem Lett 2007; 18:252-5. [PMID: 18006308 DOI: 10.1016/j.bmcl.2007.10.090] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2007] [Revised: 10/22/2007] [Accepted: 10/25/2007] [Indexed: 11/29/2022]
Abstract
A series of novel 2-alkoxy- and 2-aryloxyiminoalkyl trifluoromethanesulfonanilide derivatives have shown significant in vitro parasiticidal activity against the ectoparasites Ctenocephalides felis and Rhipicephalus sanguineus. A number of these compounds also displayed significant in vitro endoparasite activity against the nematode Haemonchus contortus.
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Affiliation(s)
- Abdelselam Ali
- CSIRO Molecular and Health Technologies, Bag 10, Clayton South, Vic. 3169, Australia
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Batten SR, Harris AR, Jensen P, Murray KS, Ziebell A. Copper(I) dicyanamide coordination polymers: ladders, sheets, layers, diamond-like networks and unusual interpenetration †. ACTA ACUST UNITED AC 2000. [DOI: 10.1039/b003527k] [Citation(s) in RCA: 132] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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15
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Schwedler R, Ziebell A, Brüggemann F, Opitz B, Kohl A, Kurz H. Band structure and electro-optical properties of mixed type-I/type-II InxGa1-xAs/InyGa1-yAs superlattices. Phys Rev B Condens Matter 1995; 52:12108-12119. [PMID: 9980353 DOI: 10.1103/physrevb.52.12108] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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16
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Hansen FR, Ziebell A, Spedtsberg K, Schroll M. [Follow-up of elderly patients in their homes by general practitioners after discharge from hospital]. Ugeskr Laeger 1991; 153:2128-31. [PMID: 1650969] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The present project which is part of a more extensive coordination project has had the goal of carrying out and assessing the proposals about follow up home visits by the general practitioner after discharge from hospital made by "The coordinating committee for the health services". General practitioners in the municipality of Roskilde made a total of 210 visits to elderly patients aged 75 years or over who had been discharged to their homes after hospitalization for at least three days. During these visits, the practitioners discovered newly developed problems in 49% of the visits while adjustment of medication proved necessary at 52% of the visits. This investigation is concerned with the risk situation, viz discharge of elderly patients from hospital but it also attempts to identify the risk groups which obtain most benefit from follow up. The majority of problems were found among the oldest patients aged 85 years and over who had been hospitalized for more than seven days. In addition, the general practitioners found that significantly more elderly patients aged 85 years and over (less than or equal to 0.05) and elderly patients who had been hospitalized for over seven days should be followed up by home visits. It is emphasized that the model outlined here would not stress the individual general practitioner's daily routine to any great extent.
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Affiliation(s)
- F R Hansen
- Amtssygehuset i Roskilde, langtidsmedicinsk afdeling
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Hansen A, Abitbol V, Ibsen KK, Merrick J, Møller U, Pedersen BK, Prahl L, Sørensen N, Ziebell A. [Conditions for children and their parents in the hospital. III. Parents' reactions in connection with the admission of the child with the diagnosis of the 1st febrile seizure]. Ugeskr Laeger 1984; 146:689-91. [PMID: 6710658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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18
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Ibsen KK, Abitbol V, Hansen A, Merrick J, Møller U, Petersen B, Prahl L, Sørensen N, Ziebell A. [The conditions for children and their parents in hospital. II. Parents admitted to a pediatric department]. Ugeskr Laeger 1983; 145:3689-91. [PMID: 6659146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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19
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Merrick J, Abitbol V, Hansen A, Ibsen KK, Møller U, Pedersen BK, Prahl L, Sørensen N, Ziebell A. [Children and parents in hospital. I. Materials and methods of child hospitalization]. Ugeskr Laeger 1983; 145:3041-4. [PMID: 6649120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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20
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Diamant B, Norn S, Felding P, Olsen N, Ziebell A, Nissen J. ATP level and CO2 production of mast cells in anaphylaxis. Int Arch Allergy Appl Immunol 1974; 47:894-908. [PMID: 4139133 DOI: 10.1159/000231280] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The short and long-term effects of the anaphylactic reaction on energy metabolism of rat mast cells were studied. The ATP content amounted to 12.1 ± 1.1 ×10<sup>––</sup><sup>16</sup> moles per mast cell in different experiments. Following antigen challenge (horse serum 0.6%), a significant decrease of the ATP level was obtained: 16% at 30 sec and 38% at 2 min with no further change up to 10 min. The decrease was evident in the absence of metabolic substrates as well as in the presence of pyruvate. However, glucose completely counteracted the fall in ATP level. The fall in ATP content and the release of histamine were both related to the antigen concentration. No change in ATP level was observed in controls or by antigen challenge of mast cells from nonsensitized rats. Pyruvate was metabolized by oxidative metabolism in the mast cell. The CO<sub>2 </sub>production amounted to 2.2 ×10<sup>––16</sup> moles CO<sub>2</sub>/mast cell/min and was completely abolished by antimycin A. Antigen challenge of sensitized rat mast cells increased the CO<sub>2</sub> production by 30%, while no increase was observed with cells from non-sensitized rats. The increase in oxidative metabolism was not correlated to the histamine release. Thus, the same enhancement in CO<sub>2</sub> production was obtained with antigen concentrations over a great range. 2,4-Dinitrophenol mimicked the effects of antigen on the ATP level as well as on the oxidative metabolism of pyruvate. The results indicate that the antigen-antibody reaction exerts effects on the energy production in the mast cells consistent with an uncoupling of oxidative phospho-rylation.
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