umu.sePublications
Change search
Refine search result
1 - 33 of 33
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Andersson, Ingegärd
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Gorzsás, András
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Kerezsi, Csaba
    Tóth, Imre
    Pettersson, Lage
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Speciation in the aqueous H+/H2VO4–/H2O2/phosphate system2005In: DALTON TRANSACTIONS, ISSN 1477-9226, Vol. 22, p. 3658-66Article in journal (Refereed)
    Abstract [en]

    The speciation in the aqueous H+/H2VO4- /phosphate (dihydrogen phosphate, P) and H+/H2VO4/H2O2/P systems has been determined in the physiological medium of 0.150 M Na(Cl) at 25 degrees C. A combination of multinuclear NMR integral and chemical shift (Bruker AMX500) as well as potentiometric data (glass electrode) have been collected and treated simultaneously by the computer program LAKE. The pK(a)-values for phosphoric acid have been determined by potentiometric and P-31 NMR chemical shift data, and have been found to be 1.85 +/- 0.02, 6.69 +/- 0.02 and 11.58 +/- 0.07. The errors given are 3 sigma. Altogether nine vanadate phosphate species have been found in the ternary H+/H2VO4-/P- system in the PH region 1-11, with the following compositions: VP, VP2 and V14P. Equilibrium is very slow in acidic solutions, requiring more than 3 months for the formation of V14P species. On the other hand, less than 15 min are needed for equilibration at neutral and alkaline pH. In the H+/H2VO4-/H2O2/P- system, four new species have been found in addition to all binary and ternary complexes. They are of VXP and VX2P compositions, where X denotes the peroxo ligand. V-51 and P-31 NMR chemical shifts, compositions and formation constants are given, and equilibrium conditions are illustrated in distribution diagrams as well as the fit of the model to the experimental data. Biological and medical relevance of the species is also discussed and physiological conditions are modelled.

  • 2.
    Andersson, Ingegärd
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Gorzsás, András
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Kerezsi, Csaba
    Tóth, Imre
    Pettersson, Lage
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Speciation in the aqueous H+/H2VO4–/H2O2/phosphate systemManuscript (Other academic)
  • 3.
    Andersson, Ingegärd
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Gorzsás, András
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Pettersson, Lage
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Speciation in the aqueous H+/H2VO4–/H2O2/picolinate system relevant to diabetes research2004In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, no 3, p. 421-428Article in journal (Refereed)
    Abstract [en]

    A detailed study of the quaternary aqueous H+/H2VO4/H2O2/picolinate (Pi) system has been performed at 25 °C in 0.150 M Na(Cl) medium using quantitative 51V NMR (500 MHz) and potentiometric data (glass electrode). In the ternary H+/H2VO4/Pi system, six complexes have been found in the pH region 1–10. In the quaternary H+/H2VO4/H2O2/Pisystem, eight additional complexes have been found. Generally, equilibria are fast in both systems. The rate of peroxide decomposition depends on the species in solution. Chemical shifts, compositions and formation constants for the species are given. Equilibrium conditions and the fit of the model to the experimental data are illustrated in distribution diagrams. Possible formation of mixed ligand species with imidazole, lactic acid and citric acid have been investigated and ruled out under the same experimental conditions. Structural proposals are given, based on 13C NMR data and available crystal structures.

  • 4. Felten, Judith
    et al.
    Hall, Hardy
    Jaumot, Joaquim
    Tauler, Roma
    de Juan, Anna
    Gorzsas, Andras
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Vibrational spectroscopic image analysis of biological material using multivariate curve resolution-alternating least squares (MCR-ALS)2015In: Nature Protocols, ISSN 1754-2189, E-ISSN 1750-2799, Vol. 10, no 2, p. 217-240Article in journal (Refereed)
    Abstract [en]

    Raman and Fourier transform IR (FTIR) microspectroscopic images of biological material (tissue sections) contain detailed information about their chemical composition. The challenge lies in identifying changes in chemical composition, as well as locating and assigning these changes to different conditions (pathology, anatomy, environmental or genetic factors). Multivariate data analysis techniques are ideal for decrypting such information from the data. This protocol provides a user-friendly pipeline and graphical user interface (GUI) for data pre-processing and unmixing of pixel spectra into their contributing pure components by multivariate curve resolution-alternating least squares (MCR-ALS) analysis. The analysis considers the full spectral profile in order to identify the chemical compounds and to visualize their distribution across the sample to categorize chemically distinct areas. Results are rapidly achieved (usually <30-60 min per image), and they are easy to interpret and evaluate both in terms of chemistry and biology, making the method generally more powerful than principal component analysis (PCA) or heat maps of single-band intensities. In addition, chemical and biological evaluation of the results by means of reference matching and segmentation maps (based on k-means clustering) is possible.

  • 5. Felten, Judith
    et al.
    Vahala, Jorma
    Love, Jonathan
    Gorzsás, András
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Ruggeberg, Markus
    Delhomme, Nicolas
    Lesniewska, Joanna
    Kangasjarvi, Jaakko
    Hvidsten, Torgeir R.
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences,Ås, Norway.
    Mellerowicz, Ewa J.
    Sundberg, Bjorn
    Ethylene signaling induces gelatinous layers with typical features of tension wood in hybrid aspen2018In: New Phytologist, ISSN 0028-646X, E-ISSN 1469-8137, Vol. 218, no 3, p. 999-1014Article in journal (Refereed)
    Abstract [en]

    The phytohormone ethylene impacts secondary stem growth in plants by stimulating cambial activity, xylem development and fiber over vessel formation. We report the effect of ethylene on secondary cell wall formation and the molecular connection between ethylene signaling and wood formation. We applied exogenous ethylene or its precursor 1-aminocyclopropane-1-carboxylic acid (ACC) to wild-type and ethylene-insensitive hybrid aspen trees (Populus tremulaxtremuloides) and studied secondary cell wall anatomy, chemistry and ultrastructure. We furthermore analyzed the transcriptome (RNA Seq) after ACC application to wild-type and ethylene-insensitive trees. We demonstrate that ACC and ethylene induce gelatinous layers (G-layers) and alter the fiber cell wall cellulose microfibril angle. G-layers are tertiary wall layers rich in cellulose, typically found in tension wood of aspen trees. A vast majority of transcripts affected by ACC are downstream of ethylene perception and include a large number of transcription factors (TFs). Motif-analyses reveal potential connections between ethylene TFs (Ethylene Response Factors (ERFs), ETHYLENE INSENSITIVE 3/ETHYLENE INSENSITIVE3-LIKE1 (EIN3/EIL1)) and wood formation. G-layer formation upon ethylene application suggests that the increase in ethylene biosynthesis observed during tension wood formation is important for its formation. Ethylene-regulated TFs of the ERF and EIN3/EIL1 type could transmit the ethylene signal.

  • 6.
    Ferro, Lorenza
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Gorzsás, András
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Gentili, Francesco G.
    Funk, Christiane
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Subarctic microalgal strains treat wastewater and produce biomass at low temperature and short photoperiod2018In: Algal Research, ISSN 2211-9264, Vol. 35, p. 160-167Article in journal (Refereed)
    Abstract [en]

    In Northern countries, microalgal-based processes are challenging due to low light and temperature conditions during a significant part of the year. Three natural strains from Northern Sweden (Chlorella vulgaris, Scenedesmus sp., Desmodesmus sp.) and a collection strain (Scenedesmus obliquus UTEX 417) were cultured in municipal wastewater, comparing their performances, biomass composition and nutrients removal under continuous light at standard (25 °C) and low temperature (5 °C), short photoperiod (3 h light, 25 °C), or moderate winter conditions (6 h light, 15 °C). Only the natural strains grew at low temperature, highly consuming total nitrogen and phosphate (>80% and >70%, respectively) even during cold- and dark-stress. At reduced growth rates, C. vulgaris and Scenedesmus sp. produced similar amounts of biomass (>1 g/l) as in standard conditions. Scenedesmus sp. and Desmodesmus sp. showed phenotypic plasticity and increased carbohydrate content. Short photoperiod strongly reduced growth rates, biomass and storage compounds and induced flocculation in C. vulgaris.

  • 7.
    Gillgren, Thomas
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Gorzsás, András
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    A one-pot set-up for real-time reaction monitoring by FTIR spectroscopy2016In: Wood Science and Technology, ISSN 0043-7719, E-ISSN 1432-5225, Vol. 50, no 3, p. 567-580Article in journal (Refereed)
    Abstract [en]

    This paper presents a method for monitoring solution reactions in real time using Fourier transform infrared (FTIR) spectroscopy. Compared to batch measurements or flow-through systems, where the reaction and spectroscopic measurements are spatially and temporarily separated, this method enables continuous FTIR spectroscopic measurements of reactions without delay and directly in the reaction vessel. The strengths are demonstrated, and the limitations of the method are highlighted using the reaction of a lignin model compound and a sulphite salt. The method is capable of identifying both kinetic and thermodynamic properties (e.g. reaction speed, intermediate species), allowing rapid and cost-effective optimisation of reaction parameters. While specificity can be limited, the non-destructive nature of the method facilitates direct coupling to other techniques to help resolve potential ambiguities. The method is of general interest in wet chemistry applications and in several areas of the lignocellulosic biomass field in particular, as it can provide new insights into natural and industrial reactions and processes.

  • 8. González Baró, Ana
    et al.
    Andersson, Ingegärd
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Pettersson, Lage
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Gorzsás, András
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Speciation in the aqueous peroxovanadate-maltol and (peroxo)vanadate-uridine systems2008In: Dalton Transactions, Vol. 8, p. 1095-102Article in journal (Refereed)
    Abstract [en]

    The speciation in the aqueous H+/H2VO4-/H2O2/maltol (Ma), H+/H2VO4-/uridine (Ur) and H+/H2VO4-/H2O2/Ur systems was determined in the physiological medium of 0.150 M Na(Cl) at 25 °C. A combination of quantitative 51V NMR (Bruker AMX500) and potentiometric data (glass electrode) was collected and treated simultaneously by the computer program LAKE. In the quaternary maltol system, the two species VXMa2- and VX2Ma2- (where X denotes the peroxo ligand) were found in the pH region 5-10, in addition to all binary and ternary complexes. Their formation was fast. In the ternary uridine (H+/H2VO4-/Ur) subsystem, altogether three vanadate-uridine (V-Ur) species were found in the pH region 4-10, with compositions VUr2-, V2Ur22- and V2Ur23-. Equilibrium was fast except in weakly acidic solutions when slowly decomposing decavanadates formed. In the quaternary H+/H2VO4-/H2O2/Ur system, five additional species were found at pH > 7. They were of VXUr and VX2Ur compositions. Their formation was fast. Formation constants, compositions and 51V NMR chemical shifts are given for all the species found in the systems, and equilibrium conditions are illustrated in distribution diagrams as well as the fit of the model to the experimental data. Biological and medical relevance of the species (in the treatment of diabetes) are also discussed, with pseudo-physiological conditions modelled.

  • 9.
    Gorzsás, András
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Vanadate and Peroxovanadate Complexes of Biomedical Relevance: A speciation approach with focus on diabetes2005Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Diabetes mellitus is one of the most threatening epidemics of modern times with rapidly increasing incidence. Vanadium and peroxovanadium compounds have been shown to exert insulin–like actions and, in contrast to insulin, are orally applicable. However, problems with side–effects and toxicity remain. The exact mechanism(s) by which these compounds act are not yet fully known. Thus, a better understanding of the aqueous chemistry of vanadates and peroxovanadates in the presence of various (bio)ligands is needed.

    The present thesis summarises six papers dealing mainly with aqueous speciation in different vanadate – and peroxovanadate – ligand systems of biological and medical relevance. Altogether, five ligands have been studied, including important blood constituents (lactate, citrate and phosphate), a potential drug candidate (picolinic acid), and a dipeptide (alanyl serine) to model the interaction of (peroxo)vanadate in the active site of enzymes. Since all five ligands have been studied both with vanadates and peroxovanadates, the number of systems described in the present work is eleven, including the vanadate – citrate – lactate mixed ligand system. The pH–independent formation constants have been determined for 33 ternary vanadate – ligand, 41 quaternary peroxovanadate – ligand and two vanadate – mixed ligand species in addition to the pKa values of all five ligands. These constants have been used to model physiological conditions, and the biomedical relevance of the different species is discussed.

    The studies have been performed at 25 ºC in the physiological medium of 0.150 M Na(Cl), i.e. the ionic strength of human blood. No buffers have been used, and wide pH–ranges have usually been covered. The applied experimental techniques comprise mostly 51V NMR and potentiometry, but 31P, 13C, 1H and 14N NMR as well as EPR and ESI–MS have also been used to gain additional information. Multimethod data have been treated by the least–squares program LAKE and modelling has been carried out by the software package WinSGW.

    Whenever possible, solution structures of the species have been proposed. In addition, simple biological tests have been carried out to determine the stability of the formed peroxovanadate complexes in the presence of human catalase. A brief comparison is given of the different vanadate – ligand and peroxovanadate – ligand systems with emphasis on observed trends and general features.

  • 10.
    Gorzsás, András
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Andersson, Ingegärd
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Pettersson, Lage
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    On the Fate of Vanadate in Human Blood2006In: European Journal of Inorganic Chemistry, Vol. 18, p. 3559-65Article in journal (Refereed)
    Abstract [en]

    The cover picture shows a symbolic representation of the fate of vanadate in human blood. Since the transition metal vanadium is named after Vanadis, the Nordic goddess of beauty, she is represented by the famous Venus de Milo sculpted in metal. Her cloth is decorated with the functional groups of the ligands that can form a complex (dress) with the metal while travelling in the blood vessels, the latter being symbolised by the caverns in the background. The water in the caves represents the aqueous solutions in which speciation studies have been carried out in the group of Professor Lage Pettersson. Further references to these studies are found as cave paintings on the walls: a distribution diagram and a set of 51V NMR spectra. The studies have been carried out in the framework of the COST D21/009 working group. The geographical locations of the research groups within this working group are shown by illuminated dots on the map of Europe in the background. The goal of the studies was to better understand the ability of vanadium to lower blood glucose levels (represented by the sugar cubes washed ashore on the left) and thus its potential as an orally applicable drug against diabetes. A Microreview, covering the results of the above mentioned speciation studies dealing with the fate of vanadate in human blood, is represented by A. Gorzsás, I. Andersson, and L. Pettersson on p. 3559 ff. The digital artwork for this cover was created by András Gorzsás.

  • 11.
    Gorzsás, András
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Andersson, Ingegärd
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Pettersson, Lage
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Speciation in Aqueous Vanadate – Ligand and Peroxovanadate – Ligand systems2009In: Journal of Inorganic Biochemistry, ISSN 0162-0134, E-ISSN 1873-3344, Vol. 103, no 4, p. 517-526Article in journal (Refereed)
    Abstract [en]

    In the present focused review, the speciation studies of aqueous vanadate-ligand (L) and peroxovanadate-L systems are addressed. The paper focuses solely on the systems studied at our department in the context of potential insulin-enhancing effects, including the following ligands: imidazole, alanylhistidine, alanylserine, lactate, picolinate, citrate, phosphate, maltol, and uridine. We summarise the results of detailed and thorough potentiometric (glass electrode) and 51V NMR (Bruker AMX-500 MHz) spectroscopic studies, performed at 25 °C in 0.150 M Na(Cl), a medium representing human blood. The importance of experimental conditions is discussed and illustrated. A detailed overview of our methodology, based on combining potentiometric and 51V integral and chemical shift data by means of the computer program LAKE, is also given. We list the important steps of equilibrium analysis and the kinds of information available from different sets of NMR spectra. The ligand picolinate is chosen to exemplify our working method, but conclusions are drawn from all systems, reviewing trends and common features. An overview of all systems is given in two tables, including e.g. types and number of species formed. Previously unpublished modelling results at physiological conditions are also shown for all peroxovanadate-ligand systems.

  • 12.
    Gorzsás, András
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Andersson, Ingegärd
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Pettersson, Lage
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Speciation in the aqueous H+/H2VO4–/H2O2/L-(+)-lactate system2003In: Dalton Transactions, p. 2503-11Article in journal (Refereed)
    Abstract [en]

    A detailed study of the quaternary aqueous H+/H2VO4–/H2O2/L-(+)-lactate (Lac–) system has been performed at 25 °C in 0.150 M Na(Cl) medium, representing the ionic strength of human blood, using quantitative 51V NMR and potentiometric data (glass electrode). Data were evaluated with the computer program LAKE, which is able to treat combined EMF and NMR data. The pKa-value for lactic acid was determined as 3.653 ± 0.002. The error given is 3. In the ternary H+/H2VO4–/Lac– system, eight complexes were found in the pH region 1.1–10.9; only half of them are mononuclear. Owing to the fast reduction of vanadium(V) in acidic solutions and to the slow equilibria of the inorganic vanadates under certain conditions, the final model of this ternary system presented in the study is limited to pH > 3.1. Solutions, in which reduction occurred to any extent, were excluded from all calculations, hence the study is limited to vanadium(V). In the quaternary H+/H2VO4–/H2O2/Lac– system, seven complexes could be found in addition to all binary and ternary complexes over the pH region 2.1–10.0, only two of which were mononuclear. Equilibrium is fast, but significant decomposition of peroxide occurs in acidic solutions over very short time, limiting the final model to pH > 4. Chemical shifts, compositions and formation constants are given, and equilibrium conditions are illustrated in distribution diagrams as well as the fit of the model to the experimental data. Simple biological tests were carried out to check the resistance of different peroxovanadate complexes (including the ones with Lac–) against human catalase and the results are being presented here.

  • 13.
    Gorzsás, András
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Andersson, Ingegärd
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Pettersson, Lage
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Speciation in the aqueous H+/H2VO4–/H2O2/L–(+)–lactate system2003In: Dalton Transactions, p. 2503-Article in journal (Refereed)
  • 14.
    Gorzsás, András
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Andersson, Ingegärd
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Schmidt, Hauke
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Rehder, Dieter
    Pettersson, Lage
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    A speciation study of the aqueous H+/H2VO4–/H2O2/L--alanyl-L-serine system2003In: Dalton Transactions, p. 1161-7Article in journal (Refereed)
    Abstract [en]

    A detailed study of the quaternary aqueous H+/H2VO4–/H2O2/L--alanyl-L-serine (Alaser) system has been performed at 25 °C in 0.150 M Na(Cl) medium, representing the ionic strength of human blood, using quantitative 51V NMR and potentiometric data (glass electrode). Data were evaluated with the computer program LAKE, which is able to treat combined EMF and NMR data. The pKa-values for Alaser were determined as 8.04 ± 0.01 and 3.07 ± 0.01. The errors given are 3. In the ternary H+/H2VO4–/Alaser system, two complexes, (H+)p(H2VO4–)q(Alaser)r, having (p, q, r) values (0, 1, 1) and (–1, 1, 1) with log0,1,1= 2.42 ± 0.01 and log–1,1,1=–5.80 ± 0.05 explain all data in the pH region 2.5–9.5. Equilibrium conditions are illustrated in distribution diagrams and structure proposals are given based on 1H and 13C NMR investigations. In the quaternary H+/H2VO4–/H2O2/Alaser system, six complexes could be found in addition to all binary and ternary complexes over the pH region 2.6–11.1, four with a V/X/Alaser ratio 1 1 1 and two with a ratio 1 2 1 (X = peroxo ligand). The formation of the monoperoxo vanadium species is very slow, requiring up to 10 days for complete equilibrium. Significant decomposition of peroxide occurs only in acidic solutions. Chemical shifts, compositions and formation constants for the six quaternary complexes are given, and equilibrium conditions are illustrated in distribution diagrams. The H+/H2VO4–/H2O2/Alaser/Alahis system, where Alahis denotes L--alanyl-L-histidine, was briefly investigated and no mixed ligand species were detected.

  • 15.
    Gorzsás, András
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Andersson, Ingegärd
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Schmidt, Hauke
    Rehder, Dieter
    Pettersson, Lage
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    A speciation study of the aqueous H+/H2VO4–/H2O2/L–α-alanyl–L–serine system2003In: Dalton Transactions, p. 1161-Article in journal (Refereed)
  • 16.
    Gorzsás, András
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Getty, Kendra
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Andersson, Ingegärd
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Pettersson, Lage
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Speciation in the aqueous H+/H2VO4–/H2O2/citrate system of biomedical interest2004In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, no 18, p. 2873-2882Article in journal (Refereed)
    Abstract [en]

    The speciation in the quaternary aqueous H+/H2VO4–/H2O2/citrate (Cit3–) and H+/H2VO4–/Cit3–/L-(+)-lactate (Lac–) systems has been determined at 25 °C in the physiological medium of 0.150 M Na(Cl). A combination of 51V NMR integral intensities and chemical shift (Bruker AMX500) as well as potentiometric data (glass electrode) have been collected and evaluated with the computer program LAKE, which is able to treat multimethod data simultaneously. The pKa-values for citric acid have been determined as 2.94, 4.34 and 5.61. Altogether six vanadate–citrate species have been found in the ternary H+/H2VO4–/Cit3– system in the pH region 2–10, only two of which are mononuclear. Reduction of vanadium(V) becomes more pronounced at pH < 2. Solutions, in which reduction occurred to any extent, were excluded from all calculations. In the quaternary H+/H2VO4–/H2O2/Cit3– system, eight complexes have been found in addition to all binary and ternary complexes over the pH region 2–10, including three mononuclear species. Equilibria in general are fast, but the significant and rapid decomposition of peroxide in acidic solutions limited the final model to pH > 4. In the quaternary H+/H2VO4–/Cit3–/Lac– system, two mixed-ligand species have been determined, with the compositions V2CitLac2– and V2CitLac3–(pKa= 5.0). To our knowledge, this is the first time such complexes have been reported for vanadium(V). 51V NMR chemical shifts, compositions and formation constants are given, and equilibrium conditions are illustrated in distribution diagrams as well as the fit of the model to the experimental data. When suitable, structural proposals are given, based on 13C NMR measurements and available literature data of related compounds.

  • 17.
    Gorzsás, András
    et al.
    Swedish University of Agricultural Sciences (SLU), Sweden.
    Stenlund, Hans
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Persson, Per
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Trygg, Johan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Sundberg, Björn
    Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences (SLU), Sweden.
    Cell specific chemotyping and multivariate imaging by combined FT-IR microspectroscopy and OPLS analysis reveals the chemical landscape of secondary xylem2011In: The Plant Journal, ISSN 0960-7412, E-ISSN 1365-313X, Vol. 66, no 5, p. 903-914Article in journal (Refereed)
    Abstract [en]

    Fourier-transform infrared (FT-IR) spectroscopy combined with microscopy enables acquiring chemical information from native plant cell walls with high spatial resolution. Combined with a 64 x 64 focal plane array (FPA) detector 4096 spectra from a 0.3 x 0.3 mm image can be simultaneously obtained, where each spectrum represents a compositional and structural "fingerprint" of all cell wall components. For optimal use and analysis of such large amount of information, multivariate approaches are preferred. Here, FT-IR microspectroscopy with FPA detection is combined with orthogonal projections to latent structures discriminant analysis (OPLS-DA). This allows for 1) the extraction of spectra from specific cell types, 2) identification and characterization of different chemotypes using the full spectral information, and 3) further visualising the pattern of identified chemotypes by multivariate imaging. As proof of concept, the chemotypes of Populus tremula xylem cell types are described. The approach revealed unknown features about chemical plasticity and patterns of lignin composition in wood fibers that would have remained hidden in the dataset with traditional data analysis. The applicability of the method on Arabidopsis xylem, and its usefulness in mutant chemotyping is also demonstrated. The methodological approach is not limited to xylem tissues but can be applied to any plant organ/tissue also using other microspectroscopy techniques such as Raman- and UV-microspectroscopy.

  • 18.
    Gustafsson, Asa
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Swetox, Karolinska Institutet, Unit of Toxicology Sciences, Forskargatan 20, SE-151 36 Södertälje, Sweden.
    Krais, Annette M.
    Gorzsás, András
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Lundh, Thomas
    Gerde, Per
    Isolation and characterization of a respirable particle fraction from residential house-dust2018In: Environmental Research, ISSN 0013-9351, E-ISSN 1096-0953, Vol. 161, p. 284-290Article in journal (Refereed)
    Abstract [en]

    Indoor air pollution has caused increasing concern in recent years. As we spend most of our lives indoors, it is crucial to understand the health effects caused by indoor air pollution. Household dust serve as good proxy for accessing indoor air pollution, especially smaller dust particles that can pass into the lungs are of interest. In this study we present an efficient method for the isolation of dust particles in the respirable size range. The respirable fraction was recovered from vacuum cleaner bags, separated by stepwise sieving, followed by characterization for size, morphology, surface area, organic content and elemental composition. The respirable fraction was obtained in a yield of 0.6% with a specific surface area of 2.5 m(2)/g and a Mass Median Aerodynamic Diameter of 3.73 +/- 0.15 mu m. Aluminum and zink were the dominating metals measured in the dust, whereas the major mineral components were found to be silicon dioxide and calcium carbonate. The fraction of organic matter in the dust was measured to be 69 +/- 1%. The organic matrix contained bacterial and fungi and a presence of skin fragments. We present here an efficient and fast method for the isolation of dust particles in the respirable size range. That is of considerable value due to the need for large quantities of respirable particle fractions to conduct toxicological studies and risk assessment work.

  • 19. Mahboubi, Amir
    et al.
    Ratke, Christine
    Gorzsas, Andras
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Kumar, Manoj
    Mellerowicz, Ewa J.
    Niittyla, Totte
    Aspen SUCROSE TRANSPORTER3 Allocates Carbon into Wood Fibers2013In: Plant Physiology, ISSN 0032-0889, E-ISSN 1532-2548, Vol. 163, no 4, p. 1729-1740Article in journal (Refereed)
    Abstract [en]

    Wood formation in trees requires carbon import from the photosynthetic tissues. In several tree species, including Populus species, the majority of this carbon is derived from sucrose (Suc) transported in the phloem. The mechanism of radial Suc transport from phloem to developing wood is not well understood. We investigated the role of active Suc transport during secondary cell wall formation in hybrid aspen (Populus tremula x Populus tremuloides). We show that RNA interference-mediated reduction of PttSUT3 (for Suc/H+ symporter) during secondary cell wall formation in developing wood caused thinner wood fiber walls accompanied by a reduction in cellulose and an increase in lignin. Suc content in the phloem and developing wood was not significantly changed. However, after (CO2)-C-13 assimilation, the SUT3RNAi lines contained more C-13 than the wild type in the Suc-containing extract of developing wood. Hence, Suc was transported into developing wood, but the Suc-derived carbon was not efficiently incorporated to wood fiber walls. A yellow fluorescent protein: PttSUT3 fusion localized to plasma membrane, suggesting that reduced Suc import into developing wood fibers was the cause of the observed cell wall phenotype. The results show the importance of active Suc transport for wood formation in a symplasmically phloem-loading tree species and identify PttSUT3 as a principal transporter for carbon delivery into secondary cell wall-forming wood fibers.

  • 20.
    Nord, Christoffer
    et al.
    Umeå University, Faculty of Medicine, Umeå Centre for Molecular Medicine (UCMM).
    Eriksson, Maria
    Umeå University, Faculty of Medicine, Umeå Centre for Molecular Medicine (UCMM).
    Dicker, Andrea
    Eriksson, Anna
    Umeå University, Faculty of Medicine, Umeå Centre for Molecular Medicine (UCMM).
    Grong, Eivind
    Ilegems, Erwin
    Marvik, Ronald
    Kulseng, Bard
    Berggren, Per-Olof
    Gorzsas, Andras
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Ahlgren, Ulf
    Umeå University, Faculty of Medicine, Umeå Centre for Molecular Medicine (UCMM).
    Biochemical profiling of diabetes disease progression by multivariate vibrational microspectroscopy of the pancreas2017In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, article id 6646Article in journal (Refereed)
    Abstract [en]

    Despite the dramatic increase in the prevalence of diabetes, techniques for in situ studies of the underlying pancreatic biochemistry are lacking. Such methods would facilitate obtaining mechanistic understanding of diabetes pathophysiology and aid in prognostic and/or diagnostic assessments. In this report we demonstrate how a multivariate imaging approach (orthogonal projections to latent structures - discriminant analysis) can be applied to generate full vibrational microspectroscopic profiles of pancreatic tissues. These profiles enable extraction of known and previously unrecorded biochemical alterations in models of diabetes, and allow for classification of the investigated tissue with regards to tissue type, strain and stage of disease progression. Most significantly, the approach provided evidence for dramatic alterations of the pancreatic biochemistry at the initial onset of immune-infiltration in the Non Obese Diabetic model for type 1 diabetes. Further, it enabled detection of a previously undocumented accumulation of collagen fibrils in the leptin deficient ob/ob mouse islets. By generating high quality spectral profiles through the tissue capsule of hydrated human pancreata and by in vivo Raman imaging of pancreatic islets transplanted to the anterior chamber of the eye, we provide critical feasibility studies for the translation of this technique to diagnostic assessments of pancreatic biochemistry in vivo.

  • 21.
    Normark, Monica
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Pommer, Linda
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Gräsvik, John
    Hedenström, Mattias
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Gorzsas, Andras
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Winestrand, Sandra
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Jönsson, Leif J.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Biochemical Conversion of Torrefied Norway Spruce After Pretreatment with Acid or Ionic Liquid2016In: Bioenergy Research, ISSN 1939-1234, E-ISSN 1939-1242, Vol. 9, no 1, p. 355-368Article in journal (Refereed)
    Abstract [en]

    The chemical effects of torrefaction and the possibility to combine torrefaction with biochemical conversion were explored in experiments with five preparations of wood of Norway spruce that had been torrefied using different degrees of severity. Compositional analysis and analyses using solid-state CP/MAS C-13 NMR, Fourier-transform infrared (FTIR) spectroscopy, and Py-GC/MS showed small gradual changes, such as decreased hemicellulosic content and increased Klason lignin value, for torrefaction conditions in the range from 260 A degrees C and 8 min up to 310 A degrees C and 8 min. The most severe torrefaction conditions (310 A degrees C, 25 min) resulted in substantial loss of glucan and further increase of the Klason lignin value, which was attributed to conversion of carbohydrate to pseudo-lignin. Even mild torrefaction conditions led to decreased susceptibility to enzymatic hydrolysis of cellulose, a state which was not changed by pretreatment with sulfuric acid. Pretreatment with the ionic liquid (IL) 1-butyl-3-methylimidazolium acetate overcame the additional recalcitrance caused by torrefaction, and the glucose yields after 72 h of enzymatic hydrolysis of wood torrefied at 260 A degrees C for 8 min and at 285 A degrees C for 16.5 min were as high as that of IL-pretreated non-torrefied spruce wood. Compared to IL-pretreated non-torrefied reference wood, the glucose production rates after 2 h of enzymatic hydrolysis of IL-pretreated wood torrefied at 260 A degrees C for 8 min and at 285 A degrees C for 16.5 min were 63 and 40 % higher, respectively. The findings offer increased understanding of the effects of torrefaction and indicate that mild torrefaction is compatible with biochemical conversion after pretreatment with alternative solvents that disrupt pseudo-lignin-containing lignocellulose.

  • 22.
    Pettersson, Lage
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Andersson, Ingegärd
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Gorzsás, András
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Speciation in peroxovanadate systems2003In: Coordination Chemistry Reviews, Vol. 237, no 1-2, p. 77-87Article in journal (Refereed)
    Abstract [en]

    Detailed and thorough potentiometric and 51V-NMR spectroscopic investigations of H+–H2VO4−–H2O2–Ligand systems have been performed at 25 °C in 0.15 M Na(Cl) ionic medium. Extensive ranges of vanadate, hydrogen peroxide and ligand concentration and of pH have been covered. The medium was chosen to represent the physiological conditions in human blood. The computer program , designed to treat different types of data simultaneously, has been used to establish the entire speciation in the systems. Before studying systems containing the ligand (L), the complete speciation in the subsystem H+–H2VO4−–H2O2 must be known under the same experimental conditions. The formation constants in this subsystem have earlier been determined and it was found that hydrogen peroxide interacts with vanadate in the whole pH range studied (0.5–10.5). In all, 10 peroxovanadate species were identified and diperoxovanadate species were found to be exceptionally stable at physiological pH. The ligands studied so far include imidazole (Im), -α-alanyl--histidine (Ah), -α-alanyl--serine (As), picolinic acid (Pi), and -(+)-lactic acid (La). In these five systems, as many as 3, 8, 6, 8, and 5 different peroxovanadate—L species (isomers included) were identified. A feature common to all these systems is that V(H2O2)2L species are formed at physiological pH. Notably, the 51V chemical shift values of diperoxovanadate moieties are always found in the range −670 to −770 ppm, and those of monoperoxovanadate from −540 to −670 ppm. The equilibrium conditions are illustrated in distribution diagrams and the effectiveness of the different ligands as complexation agents are compared. In the case of diperoxovanadate complexes, ligands with aromatic nitrogen (Im, Pi, Ah) are the most effective, the one with both aliphatic nitrogen and oxygen (As) is less effective, and the one with oxygen only (La) is the least preferred.

  • 23. Ratke, Christine
    et al.
    Pawar, Prashant Mohan-Anupama
    Balasubramanian, Vimal K.
    Naumann, Marcel
    Duncranz, Mathilda Lonnas
    Derba-Maceluch, Marta
    Gorzsas, Andras
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Endo, Satoshi
    Ezcurra, Ines
    Mellerowicz, Ewa J.
    Populus GT43 family members group into distinct sets required for primary and secondary wall xylan biosynthesis and include useful promoters for wood modification2015In: Plant Biotechnology Journal, ISSN 1467-7644, E-ISSN 1467-7652, Vol. 13, no 1, p. 26-37Article in journal (Refereed)
    Abstract [en]

    The plant GT43 protein family includes xylosyltransferases that are known to be required for xylan backbone biosynthesis, but have incompletely understood specificities. RT-qPCR and histochemical (GUS) analyses of expression patterns of GT43 members in hybrid aspen, reported here, revealed that three clades of the family have markedly differing specificity towards secondary wall-forming cells (wood and extraxylary fibres). Intriguingly, GT43A and B genes (corresponding to the Arabidopsis IRX9 clade) showed higher specificity for secondary-walled cells than GT43C and D genes (IRX14 clade), although both IRX9 and IRX14 are required for xylosyltransferase activity. The remaining genes, GT43E, F and G (IRX9-L clade), showed broad expression patterns. Transient transactivation analyses of GT43A and B reporters demonstrated that they are activated by PtxtMYB021 and PNAC085 (master secondary wall switches), mediated in PtxtMYB021 activation by an AC element. The high observed secondary cell wall specificity of GT43B expression prompted tests of the efficiency of its promoter (pGT43B), relative to the CaMV 35S (35S) promoter, for overexpressing a xylan acetyl esterase (CE5) or downregulating REDUCED WALL ACETYLATION (RWA) family genes and thus engineering wood acetylation. CE5 expression was weaker when driven by pGT43B, but it reduced wood acetyl content substantially more efficiently than the 35S promoter. RNAi silencing of the RWA family, which was ineffective using 35S, was achieved when using GT43B promoter. These results show the utility of the GT43B promoter for genetically engineering properties of wood and fibres.

  • 24.
    Reyes, Diana Carolina Alban
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Gorzsas, Andras
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Stridh, Kjell
    de Wit, Paul
    Sundman, Ola
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Alkalization of dissolving cellulose pulp with highly concentrated caustic at low NaOH stoichiometric excess2017In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 165, p. 213-220Article in journal (Refereed)
    Abstract [en]

    We present a quantitative study, using Raman spectroscopy combined with multivariate data analysis, to determine the degree of activation of softwood sulphite dissolving cellulose pulp by aqueous sodium hydroxide. We have chosen industrially relevant conditions, including low stoichiometric ratio of NaOH/Anhydroglucose Unit (AGU) <2 and highly concentrated caustic (>= 45% w/w [NaOH]). A design of experiments is used to investigate the effects of simultaneous variation of a set of key parameters on the degree of activation (i.e. transformation to alkali cellulose, denoted as DoA): (a) the NaOH/AGU stoichiometric ratio, denoted (r); (b) the concentration of NaOH, denoted [NaOH]; (c) temperature, denoted (T); and (d) reaction time, denoted (t). Solid-state C-13 CP/MAS NMR spectroscopy was applied to investigate the reproducibility of the experiments and to select the range for (t). According to the model, (r) is found to have a statistically significant effect on DoA (increasing from DoA= 6-30% at the lowest (r)=0.8, to DoA= 48-87% at the highest (r)=1.8), together with [NaOH]. The influence of [NaOH] depends strongly on (r). The other studied variables are found to be insignificant in the model and has a complicated influence on the activation. In particular, (T) is found to be unimportant in the studied range (30-60 degrees C), but increasing (t) from 5 to 25 min shows a positive influence on DoA, depending on both (r) and [NaOH]. A mercerisation mechanism that is controlled by diffusion is proposed to explain these phenomena. 

  • 25.
    Roach, Melissa
    et al.
    Swedish University of Agricultural Sciences.
    Gerber, Lorenz
    Swedish University of Agricultural Sciences.
    Sandquist, David
    Gorzsás, András
    Swedish University of Agricultural Sciences.
    Hedenström, Mattias
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Kumar, Manoj
    Swedish University of Agricultural Sciences.
    Steinhauser, Marie Caroline
    Feil, Regina
    Daniel, Geoffrey
    Stitt, Mark
    Sundberg, Björn
    Swedish University of Agricultural Sciences.
    Niittylä, Totte
    Swedish University of Agricultural Sciences.
    Fructokinase is required for carbon partitioning to cellulose in aspen wood2012In: The Plant Journal, ISSN 0960-7412, E-ISSN 1365-313X, Vol. 70, no 6, p. 967-977Article in journal (Refereed)
    Abstract [en]

    Sucrose is the main transported form of carbon in several plant species, including Populus species. Sucrose metabolism in developing wood has therefore a central role in carbon partitioning to stem biomass. Half of the sucrose-derived carbon is in the form of fructose, but metabolism of fructose has received little attention as a factor in carbon partitioning to walls of wood cells. We show that RNAi-mediated reduction of FRK2 activity in developing wood of hybrid aspen (Populus tremula × tremuloides) led to the accumulation of soluble neutral sugars and a decrease in hexose phosphates and UDP-glucose, indicating that carbon flux to cell-wall polysaccharide precursors is decreased. Reduced FRK2 activity also led to thinner fiber cell walls with a reduction in the proportion of cellulose. No pleiotropic effects on stem height or diameter were observed. The results establish a central role for FRK2 activity in carbon flux to wood cellulose.

  • 26.
    Serk, Henrik
    et al.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Gorzsás, András
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Tuominen, Hannele
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Pesquet, Edouard
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Cooperative lignification of xylem tracheary elements2015In: Plant Signalling & Behavior, ISSN 1559-2316, E-ISSN 1559-2324, Vol. 10, no 4, article id e1003753Article in journal (Refereed)
    Abstract [en]

    The development of xylem tracheary elements (TEs) – the hydro-mineral sap conducting cells - has been an evolutionary breakthrough to enable long distance nutrition and upright growth of vascular land plants. To allow sap conduction, TEs form hollow laterally reinforced cylinders by combining programmed cell death and secondary cell wall formation. To ensure their structural resistance for sap conduction, TE cell walls are reinforced with the phenolic polymer lignin, which is deposited after TE cell death by the cooperative supply of monomers and other substrates from the surrounding living cells.

  • 27.
    Sheng, Ming
    et al.
    Umeå University, Faculty of Medicine, Umeå Centre for Molecular Medicine (UCMM).
    Gorzsás, András
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Tuck, Simon
    Umeå University, Faculty of Medicine, Umeå Centre for Molecular Medicine (UCMM).
    Fourier transform infrared microspectroscopy for the analysis of the biochemical composition of C. elegans worms2016In: Worm, E-ISSN 2162-4054, Vol. 5, no 1, article id e1132978Article in journal (Refereed)
    Abstract [en]

    Changes in intermediary metabolism have profound effects on many aspects of C. elegans biology including growth, development and behavior. However, many traditional biochemical techniques for analyzing chemical composition require relatively large amounts of starting material precluding the analysis of mutants that cannot be grown in large amounts as homozygotes. Here we describe a technique for detecting changes in the chemical compositions of C. elegans worms by Fourier transform infrared microspectroscopy. We demonstrate that the technique can be used to detect changes in the relative levels of carbohydrates, proteins and lipids in one and the same worm. We suggest that Fourier transform infrared microspectroscopy represents a useful addition to the arsenal of techniques for metabolic studies of C. elegans worms.

  • 28.
    Stenlund, Hans
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Gorzsás, András
    Swedish Agricultural University.
    Persson, Per
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Sundberg, Björn
    Trygg, Johan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Orthogonal Projections to Latent Structures Discriminant Analysis Modeling on in Situ FT-IR Spectral Imaging of Liver Tissue for Identifying Sources of Variability.2008In: Analytical Chemistry, ISSN 1520-6882, Vol. 80, no 18, p. 6898-906Article in journal (Refereed)
    Abstract [en]

    In this study, the orthogonal projections to latent structures discriminant analysis (OPLS-DA) method was used to assess the in situ chemical composition of two different cell types in mouse liver samples, hepatocytes and erythrocytes. High spatial resolution FT-IR microspectroscopy equipped with a focal plan array (FPA) detector is capable of simultaneously recording over 4000 spectra from 64 x 64 pixels with a maximum spatial resolution of about 5 mum x 5 mum, which allows for the differentiation of individual cells. The main benefit with OPLS-DA lies in the ability to separate predictive variation (between cell type) from variation that is uncorrelated to cell type in order to facilitate understanding of different sources of variation. OPLS-DA was able to differentiate between chemical properties and physical properties (e.g., edge effects). OPLS-DA model interpretation of the chemical features that separated the two cell types clearly highlighted proteins and lipids/bile acids. The modeled variation that was uncorrelated to cell type made up a larger portion of the total variation and displayed strong variability in the amide I region. This could be traced back to a gradient in the high intensity (high-density) areas vs the low intensity areas (close to empty areas) that as a result of normalization had an adverse effect on FT-IR spectral profiles. This highlights that OPLS-DA provides an effective solution to identify different sources of variability, both predictive and uncorrelated, and also facilitates understanding of any sampling, experimental, or preprocessing issues.

  • 29.
    Strunk, Peter
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Öman, Tommy
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Gorzsás, András
    Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences (SLU), Umeå, Sweden.
    Hedenström, Mattias
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Eliasson, Bertil
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Characterization of dissolving pulp by multivariate data analysis of FT-IR and NMR spectra2011In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 26, no 4, p. 398-409Article in journal (Refereed)
    Abstract [en]

    Several grades of dissolving pulps have been analyzed using FT-IR, solid state13C NMR and two dimensional1H-13C HSQC NMR spectroscopy to obtain an extensive data set for further characterization. The selection of the dissolving pulps with high cellulose purity was based on pulping process, wood type and, intrinsic pulp viscosity. Multivariate data analysis was used to investigate how information derived from the spectroscopic data correlate to each of the selection criterion: wood type, process type and viscosity. The spectroscopic methods were also compared with common dissolving pulp analyses to see to what extent spectroscopy can predict pulp analyses.

    Correlations were found between the spectroscopic data and the pulp characteristics process type and wood type, but not for intrinsic viscosity. A reason for a good correlation to wood type appears to be the hemicelluloses composition, expressed as the xylose:mannose ratio by 2D NMR spectroscopy. For process type, 2D NMR showed the most characteristic property to be the amount of reducing ends in the cellulosic samples, which in turn strongly correlates to lower molecular weight for the sulfite samples as determined by molecular weight distribution.

    Many common, yet expensive and time consuming, pulp analyses could also be predicted by the achieved models. It can be concluded that investigations of dissolving pulp characteristics, especially concerning different wood and process types, can take advantage of the methods and models presented in this study.

  • 30. Tsai, Alex Y-L
    et al.
    Canam, Thomas
    Gorzsás, András
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Mellerowicz, Ewa J
    Campbell, Malcolm M
    Master, Emma R
    Constitutive expression of a fungal glucuronoyl esterase in Arabidopsis reveals altered cell wall composition and structure2012In: Plant Biotechnology Journal, ISSN 1467-7644, E-ISSN 1467-7652, Vol. 10, no 9, p. 1077-1087Article in journal (Refereed)
    Abstract [en]

    A family 15 carbohydrate esterase (CE15) from the white-rot basidiomycete, Phanerochaete carnosa (PcGCE), was transformed into Arabidopsis thaliana Col-0 and was expressed from the constitutive cauliflower mosaic virus 35S promoter. Like other CE15 enzymes, PcGCE hydrolyzed methyl-4-O-methyl-d-glucopyranuronate and could target ester linkages that contribute to lignin-carbohydrate complexes that form in plant cell walls. Three independently transformed Arabidopsis lines were evaluated in terms of nine morphometric parameters, total sugar and lignin composition, cell wall anatomy, enzymatic saccharification and xylan extractability. The transgenic lines consistently displayed a leaf-yellowing phenotype, as well as reduced glucose and xylose content by as much as 30% and 35%, respectively. Histological analysis revealed 50% reduction in cell wall thickness in the interfascicular fibres of transgenic plants, and FT-IR microspectroscopy of interfascicular fibre walls indicated reduction in lignin cross-linking in plants overexpressing PcGCE. Notably, these characteristics could be correlated with improved xylose recovery in transgenic plants, up to 15%. The current analysis represents the first example whereby a fungal glucuronoyl esterase is expressed in Arabidopsis and shows that the promotion of glucuronoyl esterase activity in plants can alter the extent of intermolecular cross-linking within plant cell walls.

  • 31. Ubeda-Tomas, Susana
    et al.
    Edvardsson, Ellinor
    Eland, Cathlene
    Singh, Sunil Kumar
    Zadik, Daniel
    Aspeborg, Henrik
    Gorzsàs, Andràs
    Swedish University of Agricultural Sciences, SE-901 83 Umea° , Sweden.
    Teeri, Tuula T
    Sundberg, Björn
    Persson, Per
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Bennett, Malcolm
    Marchant, Alan
    Genomic-assisted identification of genes involved in secondary growth in Arabidopsis utilising transcript profiling of poplar wood-forming tissues2007In: Physiologia Plantarum, Vol. 129, no 2, p. 415-28Article in journal (Refereed)
    Abstract [en]

    Despite the importance of secondary growth in plants, relatively few genes regulating this process have been identified to date. By using data from detailed transcript profiling of the poplar wood-forming tissues, 150 genes that are differentially expressed within the zone of secondary growth were identified. In order to determine the possible function of these poplar genes, potential Arabidopsis thaliana orthologs were identified and gene knockout lines analysed. Three selection filters were used to identify the most likely orthologous genes using poplar and Arabidopsis sequence comparisons, expression profiling in secondary thickened Arabidopsis hypocotyls and global expression analysis of Arabidopsis tissues. Three genes encoding AtCSLA2 (At5g22740), the AtGUT1 GT47 glycosyltransferase (At1g27440) and a protein with no proposed function AtUNKA (At4g27435) were selected for further detailed analysis of their role in secondary growth in Arabidopsis. The presented genome-based approach using both poplar and Arabidopsis systems provides powerful means towards assigning biological functions to enzymes with poorly understood biochemical activity, such as AtCSLA2 and AtGUT1, as well as for proteins with no known function.

  • 32. Wojciechowska, Agnieszka
    et al.
    Janczak, Jan
    Rojek, Tomasz
    Gorzsás, Andras
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Malik-Gajewska, Magdalena
    Duczmal, Marek
    Isothiocyanate controlled architecture, spectroscopic, and magnetic behavior of copper(II) l-arginine complexes2019In: Journal of coordination chemistry (Print), ISSN 0095-8972, E-ISSN 1029-0389Article in journal (Refereed)
    Abstract [en]

    We synthesized an l-arginine complex with the formula [Cu(l-Arg)(2)(NCS)](NCS)H2O (1) (l-Arg = l-arginine). Two cis-chelated l-arginine zwitterions form the basal plane, while the weakly N-bonded isothiocyanate is located at the apex of the distorted square pyramidal structure (=0.143). The non-coordinated NCS- anions held layers together in a 3-D supramolecular network. The crystal structure, spectroscopic (FT-IR, Raman, NIR-Vis-UV, EPR) and magnetic properties of 1 have been compared with [Cu(l-Arg)(NCS)(2)] (2). For 1, two absorptions are observed for (C=N) stretching vibrations, corresponding to NCS- ions N-bonded to the central Cu(II) (2077cm(-1)) and in the lattice (2057cm(-1)). In 2 a single band is observed at 2102cm(-1), indicating equivalent NCS- ions in the structure. The EPR spectra of complexes show anisotropic signal with g(perpendicular to) and g(||) 2.062, 2.235 (1), and 2.08, 2.225 (2) characteristic for cis-N2O2 and N3O donor sets in the xy plane, respectively. The unpaired electron mainly occupies the d(x2-y2) orbital, also confirmed by the single envelope of d-d bands at ca. 16,000cm(-1) for 1 and 16,500cm(-1) for 2. The magnetic properties ofcompounds are characteristic of a very weak antiferromagnetic interaction with J=-0.055cm(-1) and J=-0.096cm(-1) for 1 and 2, respectively. [GRAPHICS] .

  • 33. Öhman, David
    et al.
    Demedts, Brecht
    Kumar, Manoj
    Gerber, Lorenz
    Gorzsás, András
    Swedish University of Agricultural Sciences, Umeå.
    Goeminne, Geert
    Hedenström, Mattias
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Ellis, Brian
    Boerjan, Wout
    Sundberg, Björn
    MYB103 is required for FERULATE-5-HYDROXYLASE expression and syringyl lignin biosynthesis in Arabidopsis stems2013In: The Plant Journal, ISSN 0960-7412, E-ISSN 1365-313X, Vol. 73, no 1, p. 63-76Article in journal (Refereed)
    Abstract [en]

    The transcription factor (TF) MYB103 has earlier been identified as a member in the transcriptional network regulating secondary wall biosynthesis in xylem tissues of Arabidopsis and proposed to act on cellulose biosynthesis. It is a direct transcriptional target of the TF SECONDARY WALL ASSOCIATED NAC DOMAIN PROTEIN 1 (SND1), and 35S-driven dominant repression or over-expression of MYB103 modifies secondary wall thickness. We identified two myb103 T-DNA insertion mutants and chemically characterised their lignocellulose by pyrolysis-GC/MS, 2D NMR, FT-IR microspectroscopy and wet chemistry. The mutants developed normally but exhibited a large change in their cell wall chemistry, marked by a 70-75% decrease in syringyl (S) lignin. Guaiacyl (G) lignin was co-ordinately increased, so that total Klason lignin was not affected. Transcript abundance of FERULATE-5-HYDROXYLASE (F5H), the key gene in S-lignin biosynthesis, was strongly decreased in the myb103 mutants, and the metabolome of the myb103 mutant and of a null mutant in F5H was very similar. Other than the modification in lignin S to G ratio, there were only very minor changes in the composition of secondary cell wall polymers in the inflorescence stem. In conclusion, we demonstrate that F5H expression and, hence, S-lignin biosynthesis is dependent on MYB103. 

1 - 33 of 33
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf