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Edlund, Ulf
Publications (10 of 31) Show all publications
Siedlecka, A., Wiklund, S., Peronne, M.-A., Micheli, F., Lesniewska, J., Sethson, I., . . . Mellerowicz, E. J. (2008). Pectin methyl esterase inhibits intrusive and symplastic cell growth in developing wood cells of Populus. Plant Physiology, 146, 554-65
Open this publication in new window or tab >>Pectin methyl esterase inhibits intrusive and symplastic cell growth in developing wood cells of Populus
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2008 (English)In: Plant Physiology, ISSN 0032-0889, Vol. 146, p. 554-65Article in journal (Refereed) Published
Abstract [en]

Wood cells, unlike most other cells in plants, grow by a unique combination of intrusive and symplastic growth. Fibers grow in diameter by diffuse symplastic growth, but they elongate solely by intrusive apical growth penetrating the pectin-rich middle lamella that cements neighboring cells together. In contrast, vessel elements grow in diameter by a combination of intrusive and symplastic growth. We demonstrate that an abundant pectin methyl esterase (PME, EC 3.1.1.11) from wood-forming tissues of hybrid aspen (Populus tremula L. x tremuloides Michx.) acts as a negative regulator of both symplastic and intrusive growth of developing wood cells. When PttPME1expression was up- and down-regulated in transgenic aspen trees, the PME activity in wood-forming tissues was correspondingly altered. PME removes methyl ester groups from homogalacturonan, and the transgenic trees had modified homogalacturonan methylesterification patterns, as demonstrated by two-dimensional NMR and immunostaining using PAM1 and LM7 antibodies. The in situ distributions of PAM1 and LM7 epitopes revealed changes in pectin methylesterification in the transgenic trees that were specifically localized in expanding wood cells. The results show that en-block de-esterification of homogalacturonan by PttPME1 inhibits both symplastic growth and intrusive growth. PttPME1 is therefore involved in mechanisms determining fiber width and length in the wood of aspen trees.

National Category
Chemical Sciences
Identifiers
urn:nbn:se:umu:diva-6462 (URN)10.1104/pp.107.111963 (DOI)18065553 (PubMedID)
Available from: 2008-02-12 Created: 2008-02-12 Last updated: 2018-06-09Bibliographically approved
Hedenström, M., Wiklund, S., Sundberg, B. & Edlund, U. (2008). Visualization and interpretation of OPLS models based on 2D NMR data. Chemometrics and Intelligent Laboratory Systems,, 92(2), 110-7
Open this publication in new window or tab >>Visualization and interpretation of OPLS models based on 2D NMR data
2008 (English)In: Chemometrics and Intelligent Laboratory Systems,, Vol. 92, no 2, p. 110-7Article in journal (Refereed) Published
Abstract [en]

Multivariate analysis on spectroscopic 1H NMR data is well established in metabolomics and other fields where the composition of complex samples are studied. However, biomarker identification can be hampered by overlapping resonances. 2D NMR data provides a more detailed "fingerprint" of the chemical structure and composition of the sample with greatly improved spectral resolution compared to 1H NMR data. In this report, we demonstrate a procedure for the construction of multivariate models based on frequency domain 2D NMR data where the loadings can be visualized as highly informative 2D loading spectra. This method is based on the analysis of raw spectral data without any need for peak picking or integration prior to analysis. Spectral features such as line widths and peak positions are thus retained. Hence, the loadings can be visualized and interpreted on a molecular level as pseudo 2D spectra in order to identify potential biomarkers. To demonstrate this strategy we have analyzed HSQC spectra acquired from populus phloem plant extracts originating from a set of designed experiments with OPLS regression.

Keywords
Metabolomics, Two-dimensional NMR spectroscopy, HSQC, Multivariate Data Analysis, OPLS, S-plot
National Category
Chemical Sciences
Identifiers
urn:nbn:se:umu:diva-8818 (URN)
Available from: 2008-05-27 Created: 2008-05-27 Last updated: 2018-06-09Bibliographically approved
Wiklund, S., Johansson, E., Sjöström, L., Mellerowicz, E. J., Edlund, U., Shockcor, J. P., . . . Trygg, J. (2008). Visualization of GC/TOF-MS-based metabolomics data for identification of biochemically interesting compounds using OPLS class models. Analytical Chemistry, 80(1), 115-22
Open this publication in new window or tab >>Visualization of GC/TOF-MS-based metabolomics data for identification of biochemically interesting compounds using OPLS class models
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2008 (English)In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 80, no 1, p. 115-22Article in journal (Refereed) Published
Abstract [en]

Metabolomics studies generate increasingly complex data tables, which are hard to summarize and visualize without appropriate tools. The use of chemometrics tools, e.g., principal component analysis (PCA), partial least-squares to latent structures (PLS), and orthogonal PLS (OPLS), is therefore of great importance as these include efficient, validated, and robust methods for modeling information-rich chemical and biological data. Here the S-plot is proposed as a tool for visualization and interpretation of multivariate classification models, e.g., OPLS discriminate analysis, having two or more classes. The S-plot visualizes both the covariance and correlation between the metabolites and the modeled class designation. Thereby the S-plot helps identifying statistically significant and potentially biochemically significant metabolites, based both on contributions to the model and their reliability. An extension of the S-plot, the SUS-plot (shared and unique structure), is applied to compare the outcome of multiple classification models compared to a common reference, e.g., control. The used example is a gas chromatography coupled mass spectroscopy based metabolomics study in plant biology where two different transgenic poplar lines are compared to wild type. By using OPLS, an improved visualization and discrimination of interesting metabolites could be demonstrated.

Place, publisher, year, edition, pages
Columbus, OH: American Chemical Society, 2008
National Category
Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:umu:diva-17996 (URN)10.1021/ac0713510 (DOI)
Available from: 2008-01-02 Created: 2008-01-02 Last updated: 2018-06-09
Wiklund, S., Karlsson, M., Antti, H., Johnels, D., Sjöström, M., Wingsle, G. & Edlund, U. (2005). A new metabonomic strategy for analysing the growth process of the poplar tree. Plant Biotechnology Journal, 3(3), 353-362
Open this publication in new window or tab >>A new metabonomic strategy for analysing the growth process of the poplar tree
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2005 (English)In: Plant Biotechnology Journal, ISSN 1467-7644, E-ISSN 1467-7652, Vol. 3, no 3, p. 353-362Article in journal (Refereed) Published
Abstract [en]

High-resolution, magic angle spinning, proton nuclear magnetic resonance (H-1 HR/MAS NMR) spectroscopy and multivariate data analysis using batch processing (BP) were applied to the analysis of two different genotypes of poplar tree (Populus tremula L. x tremuloides Michx.) containing an antisense construct of PttMYB76 and control (wild-type). A gene encoding a MYB transcription factor, with unknown function, PttMYB76, was selected from a cambial expressed sequence tag (EST) library of poplar tree (Populus tremula L. x tremuloides Michx.) for metabonomic characterization. The PttMYB76 gene is believed to affect different paths in the phenyl propanoid synthetic pathway. This pathway leads to the formation of S- and G-lignin, flavonoids and sinapate esters. Milled poplar samples collected at the internodes of the tree were analysed using H-1 HR/MAS NMR spectroscopy. The application of multivariate BP of the NMR results revealed a growth-related gradient in the plant internode direction, as well as the discrimination between the trees with down-regulated PttMYB76 expression and wild-type populations. This paper focuses on the potential of a new analytical multivariate approach for analysing time-related plant metabonomic data. The techniques used could, with the aid of suitable model compounds, be of high relevance to the detection and understanding of the different lignification processes within the two types of poplar tree. Additionally, the findings highlight the importance of applying robust and organized multivariate data analysis approaches to facilitate the modelling and interpretation of complex biological data sets.

Keywords
batch process, H-1 HR/MAS NMR, partial least squares projections to latent structures, poplar tree, principal components analysis, wood formation
National Category
Chemical Sciences
Identifiers
urn:nbn:se:umu:diva-13245 (URN)10.1111/j.1467-7652.2005.00129.x (DOI)
Available from: 2007-05-07 Created: 2007-05-07 Last updated: 2018-06-09Bibliographically approved
Edlund, U., Wiklund, S., Antti, H., Karlsson, M. & Wingsle, G. (Eds.). (2005). Batch process strategy for analysing metabolic variation controlling the growth process of hybrid aspen.
Open this publication in new window or tab >>Batch process strategy for analysing metabolic variation controlling the growth process of hybrid aspen
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2005 (English)Conference proceedings (editor) (Other (popular science, discussion, etc.))
Abstract [en]

High resolution magic angle spinning proton nuclear magnetic resonance spectroscopy, {1}H HR/MAS NMR, and multivariate data analysis using batch processing, BP, was applied for the analysis of two different genotypes of poplar tree (Populus tremula L. x tremuloides Michx.), containing an antisense construct of PttMYB76 and control (wild type). A gene encoding a MYB transcription factor, with unknown function, PttMYB76, was selected from a cambial EST library of poplar tree (Populus tremula L. x remuloides Michx.) for metabonomic characterisation. The PttMYB76 gene is believed to affect different paths of the phenyl propanoid synthetic pathway. This pathway leads to the formation of S- and G-lignin, flavonoids and sinapate esters. Milled poplar samples collected at the internodes of the tree were analysed using {1}H high resolution magic angle spinning NMR spectroscopy. The application of multivariate batch processing of the NMR results revealed a growth-related gradient in the plant internode direction as well as the discrimination between the trees with down regulated PttMYB76 expression and wild type populations. This paper is focused on the potential of a new analytical multivariate approach for analysing time-related plant metabonomic data. The techniques used could, with the aid of suitable model compounds, be of high relevance to the detection and understanding of the different lignification processes within the two types of poplar tree. Additionally, the findings are highlighting the importance of applying robust and organised multivariate data analysis approaches to facilitate modelling and interpretation of complex biological data sets.

Publisher
p. 8
National Category
Chemical Sciences
Identifiers
urn:nbn:se:umu:diva-20680 (URN)0958554897 (ISBN)
Note

59th Appita Annual Conference and Exhibition: Incorporating the 13th ISWFPC (International Symposium on Wood, Fibre and Pulping Chemistry), Auckland, New Zealand, 16-19 May 2005: Proceedings; volume 2, sid 195-202

Available from: 2009-03-24 Created: 2009-03-24 Last updated: 2018-06-09Bibliographically approved
Gromov, S., Vedernikov, A., Ushakov, E., Lobova, N., Botsmanova, A., Kuz'mina, L., . . . Edlund, U. (2005). Novel supramolecular charge-transfer systems based on bis(18-crown-6)stilbene and viologen analogues bearing two ammonioalkyl groups. NEW JOURNAL OF CHEMISTRY, 29(7), 881-94
Open this publication in new window or tab >>Novel supramolecular charge-transfer systems based on bis(18-crown-6)stilbene and viologen analogues bearing two ammonioalkyl groups
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2005 (English)In: NEW JOURNAL OF CHEMISTRY, ISSN 1144-0546, Vol. 29, no 7, p. 881-94Article in journal (Refereed) Published
Abstract [en]

A series of new viologen analogues bearing two ammonioalkyl groups (2-4) were synthesized in order to study their complexation with bis(18-crown-6)stilbene (1b). Electronic spectroscopy and H-1 NMR measurements show that in acetonitrile, bis( crown) stilbene 1b forms highly stable 1 : 1 and 2 : 1 charge-transfer (CT) complexes with pi-acceptors 2-4 owing to host-guest bonding. The influence of geometric and electronic factors on the complex formation constants are discussed. The structures of the supramolecular CT complexes are analyzed on the basis of H-1 and C-13 NMR data obtained in solution and in the solid state. X-Ray diffraction data for 1b and for model tetramethoxystilbene are also reported.

Keywords
DONOR-ACCEPTOR COMPLEXES, CONTAINING STYRYL DYES, SOLID-STATE, STILBENE, ETHERS, RECOGNITION, SENSORS, NMR
National Category
Chemical Sciences
Identifiers
urn:nbn:se:umu:diva-13403 (URN)10.1039/b500667h (DOI)
Available from: 2008-04-10 Created: 2008-04-10 Last updated: 2018-06-09Bibliographically approved
Nilsson, D. & Edlund, U. (2005). Pine and spruce roundwood species classification using multivariate image analysis on bark. Holzforschung, 59(6), 689-695
Open this publication in new window or tab >>Pine and spruce roundwood species classification using multivariate image analysis on bark
2005 (English)In: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 59, no 6, p. 689-695Article in journal (Refereed) Published
Abstract [en]

Wood discs from 67 pine and 79 spruce logs were collected from a forest clearing. Three different 24-bit red-green-blue (RGB) images were acquired from the radial surface of each disc. The first image contained bark, the second image was a mixture of bark and wood surface, and the third image consisted only of wood surface. The image texture was compressed into vectors of Fourier-transformed wavelet coefficients. These were assembled in matrices and analysed by principal component analysis (PCA) and partial least-squares projections to latent structures (PLS). Classification using Fourier-transformed wavelet scales showed that the wood species could be predicted with 90% accuracy. A thorough examination of this classification showed that the predicting power of these models was mostly due to wavelet scales that represented the mean value of each colour channel. The prediction accuracy that could be obtained from coefficients representing image texture was generally low. The use of grey-level co-occurrence matrices prior to the wavelet transformation showed, however, that it is possible to classify the wood species of pine and spruce with an accuracy approaching 100%.

Place, publisher, year, edition, pages
Berlin: Walter de Gruyter, 2005
Keywords
bark, co-occurrence matrix, multivariate image analysis, partial least squares projection to latent structures (PLS), pine, spruce, wavelet, wood species
National Category
Chemical Sciences
Identifiers
urn:nbn:se:umu:diva-4724 (URN)10.1515/HF.2005.110 (DOI)
Available from: 2005-10-06 Created: 2005-10-06 Last updated: 2018-06-09Bibliographically approved
Nilsson, D., Edlund, U., Sjöström, M. & Agnemo, R. (2005). Prediction of thermo mechanical pulp brightness using NIR spectroscopy on wood raw material. Paperi ja puu, 87(2), 102-109
Open this publication in new window or tab >>Prediction of thermo mechanical pulp brightness using NIR spectroscopy on wood raw material
2005 (English)In: Paperi ja puu, ISSN 0031-1243, Vol. 87, no 2, p. 102-109Article in journal (Refereed) Published
Abstract [en]

Partial Least Squares regression to latent structures was used to find a correlation between near-infrared reflectance spectra of samples of milled Norway Spruce (Picea abies) and ISO brightness of bleached thermo mechanical pulp. Logs of spruce were stored in climate chambers with different conditions for 14 weeks. A factorial design based on five variables was constructed to control the storage and to provide different brightness properties of the stored spruce logs. Wood samples were collected during the storage and they were analysed with near-infrared reflectance spectroscopy and later refined to thermo mechanical pulp. The pulp was bleached with both hydrogen peroxide and sodium dithionite. The ISO brightness of the bleached pulp was correlated to the near-infrared spectra of the untreated samples using Partial Least Squares regression to latent structures. The modelling showed that it is possible to predict the ISO brightness of bleached thermo mechanical pulp from near-infrared spectra of original wood raw material.

Place, publisher, year, edition, pages
Helsinki: Suomen Paperi- ja Puutavaralehti Oy, 2005
Keywords
near-infrared, spectroscopy, principal component analysis, partial least squares regression to latent variables, thermo mechanical pulp, ISO brightness
National Category
Chemical Sciences
Identifiers
urn:nbn:se:umu:diva-13237 (URN)
Available from: 2007-05-07 Created: 2007-05-07 Last updated: 2018-06-09Bibliographically approved
Gromov, S. P., Vedernikov, A. I., Fedorov, Y. V., Fedorova, O. A., Andryukhina, E. N., Shepel, N. E., . . . Alfimov, M. V. (2005). Self-assembly of a (benzothiazolyl)ethenylbenzocrown ether into a sandwich complex and stereoselective [2+2] photocycloaddition. RUSSIAN CHEMICAL BULLETIN, 54(7), 1569-79
Open this publication in new window or tab >>Self-assembly of a (benzothiazolyl)ethenylbenzocrown ether into a sandwich complex and stereoselective [2+2] photocycloaddition
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2005 (English)In: RUSSIAN CHEMICAL BULLETIN, ISSN 1066-5285, Vol. 54, no 7, p. 1569-79Article in journal (Refereed) Published
Abstract [en]

In the presence of Ba2+ ions, (benzothiazolyl)ethenylbenzocrown ether forms the stable sandwich complex 2L center dot Ba2+ with an unusual structure, in which the benzothiazole fragments are arranged one above the other. Irradiation of the sandwich complex with visible light induces stereoselective [2+2] cycloaddition giving rise to two "head-to-head" isomers of biscrown-cyclobutane. The addition of dibasic dicarboxylic acids that additionally stabilize the sandwich complex in a favorable conformation affects the isomer ratio of the cyclobutanes formed. The conformational equilibria for the sandwich complex and cyclobutanes were studied by H-1 N MR spectroscopy.

Keywords
hetarylphenylethylenes, (benzothiazolyl)ethenylbenzocrown ether, complexation, barium, sandwich complexes, cycloaddition, cyclobutanes, dicarboxylic acids
National Category
Chemical Sciences
Identifiers
urn:nbn:se:umu:diva-13394 (URN)10.1007/s11172-006-0005-9 (DOI)
Available from: 2007-05-08 Created: 2007-05-08 Last updated: 2018-06-09Bibliographically approved
Buevich, A. V., Lundberg, S., Sethson, I., Edlund, U. & Backman, L. (2004). NMR studies of calcium-binding to mutant alpha-spectrin EF-hands. CELLULAR & MOLECULAR BIOLOGY LETTERS, 9(1), 167-86
Open this publication in new window or tab >>NMR studies of calcium-binding to mutant alpha-spectrin EF-hands
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2004 (English)In: CELLULAR & MOLECULAR BIOLOGY LETTERS, ISSN 1425-8153, Vol. 9, no 1, p. 167-86Article in journal (Refereed) Published
Abstract [en]

The co-operative calcium binding mechanism of the two C-terminal EF-hands of human all-spectrin has been investigated by site-specific mutagenesis and multi-dimensional NMR spectroscopy. To analyse the calcium binding of each EF-hand independently, two mutant structures (E33A and D69S) of wild type alpha-spectrin were prepared. According to NMR analysis both E33A and D69S were properly folded. The unmutated EF-hand in these mutants remained nearly intact and active in calcium binding, whereas the mutated EF-hand lost its affinity for calcium completely. The apparent calcium binding affinity of the E33A mutant was much lower compared to the D39S mutant (similar to2470 muM and similar to240 muM, respectively). When the chemical shift perturbations were followed upon calcium titration, a positive correlation between the D69S mutant and the binding of the first calcium ion to the wild type was revealed. These observations showed that the first EF-hand in spectrin binds the first calcium ion and thereby triggers a conformational change that allows the second calcium ion to bind to the other EF-hand.

Keywords
EF-hand, site-specific mutagenesis, multidimensional NMR
National Category
Chemical Sciences
Identifiers
urn:nbn:se:umu:diva-14274 (URN)
Available from: 2007-05-28 Created: 2007-05-28 Last updated: 2018-06-09Bibliographically approved
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