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  • 1. Anugwom, Ikenna
    et al.
    Eta, Valerie
    Virtanen, Pasi
    Mäki-Arvela, Paivi
    Hedenström, Mattias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Yibo, Ma
    Hummel, Micheal
    Sixta, Herbert
    Mikkola, Jyri-Pekka
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Laboratory of Industrial Chemistry and Reaction Engineering, Process Chemistry Centre, Åbo Akademi University.
    Towards optimal selective fractionation for Nordic woody biomass using novel amine–organic superbase derived switchable ionic liquids (SILs)2014Ingår i: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 70, s. 373-381Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Abstract Improved fractionation process conditions for wood dissolution with switchable ionic liquids (SILs) were determined. The short time, high temperature (STHT) system was introduced as a selective and efficient way to extract components from lignocellulosic material. A SIL based on monoethanol amine (MEA) and 1,8-diazabicyclo-[5.4.0]-undec-7-ene (DBU) formed via coupling with SO2, was applied as a solvent in a 1:3 weight ratio with water. In essence, selective dissolution of mainly lignin was achieved by means of the aqueous SIL at 160 °C (∼6.1 bar corresponding to the vapor pressure of water) in 2 h and in a pressure vessel, for both hard- and soft-wood. About 95 wt-% of wood lignin was extracted. The dissolved components in the spent SIL were recovered by the addition of an anti-solvent whereupon over 70% of the dissolved components were recovered; the recovered fraction contained 19 wt-% hemicellulose while the rest of the material was in essence lignin. The non-dissolved, fluffy material contained ∼70 wt-% cellulose and ∼20 wt-% hemicellulose – a consistency resembling that of Kraft pulp.

  • 2. Anugwom, Ikenna
    et al.
    Eta, Valerie
    Virtanen, Pasi
    Mäki-Arvela, Päivi
    Hedenström, Mattias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Hummel, Michael
    Sixta, Herbert
    Mikkola, Jyri-Pekka
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Switchable ionic liquids as delignification solvents for lignocellulosic materials2014Ingår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 7, nr 4, s. 1170-1176Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The transformation of lignocellulosic materials into potentially valuable resources is compromised by their complicated structure. Consequently, new economical and feasible conversion/fractionation techniques that render value-added products are intensely investigated. Herein an unorthodox and feasible fractionation method of birch chips (B. pendula) using a switchable ionic liquid (SIL) derived from an alkanol amine (monoethanol amine, MEA) and an organic super base (1,8-diazabicyclo-[5.4.0]-undec-7-ene, DBU) with two different trigger acid gases (CO2 and SO2 ) is studied. After SIL treatment, the dissolved fractions were selectively separated by a step-wise method using an antisolvent to induce precipitation. The SIL was recycled after concentration and evaporation of anti-solvent. The composition of undissolved wood after MEA-SO2 -SIL treatment resulted in 80 wt % cellulose, 10 wt % hemicelluloses, and 3 wt % lignin, whereas MEA-CO2 -SIL treatment resulted in 66 wt % cellulose, 12 wt % hemicelluloses and 11 wt % lignin. Thus, the MEA-SO2 -SIL proved more efficient than the MEA-CO2 -SIL, and a better solvent for lignin removal. All fractions were analyzed by gas chromatography (GC), Fourier transform infrared spectroscopy (FT-IR), (13) C nuclear magnetic resonance spectroscopy (NMR) and Gel permeation chromatography (GPC).

  • 3. Anugwom, Ikenna
    et al.
    Maki-Arvela, Paivi
    Virtanen, Pasi
    Willfor, Stefan
    Damlin, Pia
    Hedenström, Mattias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Mikkola, Jyri-Pekka
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Treating birch wood with a switchable 1,8-diazabicyclo-[5.4.0]-undec-7-ene-glycerol carbonate ionic liquid2012Ingår i: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 66, nr 7, s. 809-815Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The suitability of a new switchable ionic liquid (SIL) has been investigated as a solvent for fractionation of lignocellulosic materials. SIL was prepared from inexpensive chemicals, e. g., glycerol, CO2, and 1,8-diazabicyclo-[5.4.0]-undec-7-ene (DBU). Fresh Nordic birch wood (B. pendula) was treated with the SIL for a time period of 1-5 days at 100 degrees C and under atmospheric pressure. Upon SIL treatment, at best, 57 % of the hemicelluloses were dissolved and 50 % of lignins were dissolved from the native birch. The slightly fibrillated SIL treated chips contained about 55 % cellulose. Up to 76 % of the recovered species removed from the spent SIL liquor was originating from hemicelluloses, mainly from xylan. The spent SILs were reused for fresh wood dissolution in four consecutive cycles and each time the wood dissolution efficiency was similar. SILs could offer affordable (easy-to-synthesize) solvent systems for partial elimination of hemicelluloses and lignin from wood. SILs can also be prepared in-situ and on-site.

  • 4.
    Anugwom, Ikenna
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Laboratory of Industrial Chemistry and Reaction Engineering, Process Chemistry Centre, Åbo Akademi University, Åbo-Turku FI-20500, Finland.
    Rujana, L.
    Wärnå, J.
    Hedenström, Mattias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Mikkola, Jyri-Pekka
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Laboratory of Industrial Chemistry and Reaction Engineering, Process Chemistry Centre, Åbo Akademi University, Åbo-Turku FI-20500, Finland.
    In quest for the optimal delignification of lignocellulosic biomass using hydrated, SO2 switched DBU MEASIL switchable ionic liquid2016Ingår i: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 297, s. 256-264Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper, various process parameters aiming at optimal short-time-high-temperature (STHT) process were studied upon fractionation of Nordic woody biomass into its primary constituents. Highly diluted, aqueous 'SO2-switched' switchable ionic liquid (SIL) based on an alkanol amine (monoethanol amine, MEA) and an organic superbase (1,8-diazabicyclo-[5.4.0]-undec-7-ene, DBU) was applied. The ultimate goal was to develop a more sustainable, environmentally friendly and cost efficient systems for efficient separation of the lignocellulosic fractions. One of the main products from the SIL fractionation is cellulose-rich pulp with very low lignin content, complemented with hemicelluloses. The NMR results reveal that substantial removal of lignin occurs even when relatively low amount of SIL was used. Further, a simple mathematical model describing the dissolution of the lignocellulose components (hemicellulose and lignin) and weight loss of wood as a function of time is described. Moreover, the most efficient process involved the use of SpinChem (R) rotating bed reactor while upon use of a flow through (loop) reactor, promising results were obtained at a treatment time of 4 h. Still, all the reactor systems studied gave rise to a rather low removal of hemicelluloses which mean that the solvent system is primary selective towards lignin dissolution.

  • 5. Berglund, Linn
    et al.
    Anugwom, Ikenna
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Laboratory of Industrial Chemistry and Reaction Engineering, Johan Gadolin Process Chemistry Centre, Åbo Akademi University, Turku, Finland.
    Hedenström, Mattias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Aitomäki, Yvonne
    Mikkola, Jyri-Pekka
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Laboratory of Industrial Chemistry and Reaction Engineering, Johan Gadolin Process Chemistry Centre, Åbo Akademi University, Turku, Finland.
    Oksman, Kristiina
    Switchable ionic liquids enable efficient nanofibrillation of wood pulp2017Ingår i: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 24, nr 8, s. 3265-3279Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Use of switchable ionic liquid (SIL) pulp offers an efficient and greener technology to produce nanofibers via ultrafine grinding. In this study, we demonstrate that SIL pulp opens up a mechanically efficient route to the nanofibrillation of wood pulp, thus providing both a low cost and chemically benign route to the production of cellulose nanofibers. The degree of fibrillation during the process was evaluated by viscosity and optical microscopy of SIL treated, bleached SIL treated and a reference pulp. Furthermore, films were prepared from the fibrillated material for characterization and tensile testing. It was observed that substantially improved mechanical properties were attained as a result of the grinding process, thus signifying nanofibrillation. Both SIL treated and bleached SIL treated pulps were fibrillated into nanofibers with fiber diameters below 15 nm thus forming networks of hydrophilic nature with an intact crystalline structure. Notably, it was found that the SIL pulp could be fibrillated more efficiently than traditional pulp since nanofibers could be produced with more than 30% less energy when compared to the reference pulp. Additionally, bleaching reduced the energy demand by further 16%. The study demonstrated that this switchable ionic liquid treatment has considerable potential in the commercial production of nanofibers due to the increased efficiency in fibrillation.

  • 6.
    Blomberg, David
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Hedenström, Mattias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Kreye, Paul
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Sethson, Ingmar
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Brickmann, Kay
    AstraZeneca R&D Mölndal, Mölndal, Sweden.
    Kihlberg, Jan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Synthesis and conformational studies of a β-turn mimetic incorporated in Leu-enkephalin2004Ingår i: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 69, nr 10, s. 3500-3508Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A β-turn mimetic in which the four amino acids of a β-turn have been replaced by a 10-membered ring has been designed, synthesized, and subjected to conformational studies. In the mimetic, the intramolecular COi − HNi+3 hydrogen bond that is often found in β-turns has been replaced by an ethylene bridge. In addition, the amide bond between residues i and i + 1 was exchanged for a methylene ether isoster. Such a β-turn mimetic, based on the first four residues of Leu-enkephalin (Tyr-Gly-Gly-Phe-Leu), was prepared in 15 steps. The synthesis relied on a β-azido alcohol prepared in five steps from Cbz-Tyr(tBu)-OH as a key, i-position building block. tert-Butyl bromoacetate, glycine, and a Phe-Leu dipetide were then used as building blocks for positions i + 1, i + 2, and i + 3, respectively. Conformational studies based on 1H NMR data showed that the β-turn mimetic was flexible, but that it resembled a type-II β-turn at low temperature. This low energy conformer closely resembled the structure determined for crystalline Leu-enkephalin.

  • 7.
    Erhagen, Björn
    et al.
    Department of Forest Ecology & Management, Swedish University of Agricultural Sciences (SLU), Umeå, Sweden.
    Öquist, Mats
    Department of Forest Ecology & Management, Swedish University of Agricultural Sciences (SLU), Umeå, Sweden.
    Sparrman, Tobias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Haei, Mahsa
    Department of Forest Ecology & Management, Swedish University of Agricultural Sciences (SLU), Umeå, Sweden.
    Ilstedt, Ulrik
    Department of Forest Ecology & Management, Swedish University of Agricultural Sciences (SLU), Umeå, Sweden.
    Hedenström, Mattias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Schleucher, Jürgen
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk kemi och biofysik.
    Nilsson, Mats B
    Department of Forest Ecology & Management, Swedish University of Agricultural Sciences (SLU), Umeå, Sweden.
    Temperature response of litter and soil organic matter decomposition is determined by chemical composition of organic material2013Ingår i: Global Change Biology, ISSN 1354-1013, E-ISSN 1365-2486, Vol. 19, nr 12, s. 3858-3871Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The global soil carbon pool is approximately three times larger than the contemporary atmospheric pool, therefore even minor changes to its integrity may have major implications for atmospheric CO2 concentrations. While theory predicts that the chemical composition of organic matter should constitute a master control on the temperature response of its decomposition, this relationship has not yet been fully demonstrated. We used laboratory incubations of forest soil organic matter (SOM) and fresh litter material together with NMR spectroscopy to make this connection between organic chemical composition and temperature sensitivity of decomposition. Temperature response of decomposition in both fresh litter and SOM was directly related to the chemical composition of the constituent organic matter, explaining 90% and 70% of the variance in Q10 in litter and SOM respectively. The Q10 of litter decreased with increasing proportions of aromatic and O-aromatic compounds, and increased with increased contents of alkyl- and O-alkyl carbons. In contrast, in SOM, decomposition was affected only by carbonyl compounds. To reveal why a certain group of organic chemical compounds affected the temperature sensitivity of organic matter decomposition in litter and SOM, a more detailed characterisation of the (13) C aromatic region using Heteronuclear Single Quantum Coherence (HSQC) was conducted. The results revealed considerable differences in the aromatic region between litter and SOM. This suggests that the correlation between chemical composition of organic matter and the temperature response of decomposition differed between litter and SOM. The temperature response of soil decomposition processes can thus be described by the chemical composition of its constituent organic matter, this paves the way for improved ecosystem modelling of biosphere feedbacks under a changing climate.

  • 8.
    Gillgren, Thomas
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Hedenström, Mattias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Jönsson, Leif J.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Comparison of laccase-catalyzed cross-linking of organosolv lignin and lignosulfonates2017Ingår i: International Journal of Biological Macromolecules, ISSN 0141-8130, E-ISSN 1879-0003, Vol. 105, nr 1, s. 438-446Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Lignin, an underutilized by-product from chemical pulping of wood, can be modified enzymatically through oxidation by laccase. However, little is known about the molecular details surrounding the cross linking which is a result of the oxidation. To reduce this lack of knowledge, we used oxygen consumption rate data, phenolic content data and molecular weight data together with data from NMR and FTIR spectroscopy to.characterize laccase-catalyzed cross-linking of the industrial lignin preparations organosolv lignin and lignosulfonate. The organosolv lignin preparation had a M-n of 780 g/mol, a M-w of 5200 g/mol, and a phenolic content of 1.8 mmol/g. The lignosulfonate preparation had a M-n of 6000 g/mol, a M-w of 19800 g/mol, and a phenolic content of 1.1 mmol/g. Laccase-catalyzed oxidation of organosolv lignin was characterized by a relatively slow increase in molecular weight, decreased intensities for aromatic signals and p-hydroxycinnamyl groups, and increased intensity for beta-O-4' signals, whereas oxidation of lignosulfonates resulted in a very rapid increase in molecular weight, and strongly decreased intensities for aromatic signals. The data suggest that lignosulfonates cross-linked by couplings to the aromatic ring (e.g. 5-5' and 4-O-5'), whereas beta-O-4' coupling characterized cross-linking of organosolv lignin, probably involving cinnamyl alcohol end-groups. (C) 2017 Published by Elsevier B.V.

  • 9.
    Gustafsson, Tomas
    et al.
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Kemi.
    Hedenström, Mattias
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Kemi.
    Kihlberg, Jan
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Kemi.
    Synthesis of a C-Glycoside Analogue of -D-Galactosyl Hydroxylysine and Incorporation in a Glycopeptide from Type II Collagen2006Ingår i: Journal of Organic Chemistry, Vol. 71, nr 5, s. 1911-9Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A stereoselective synthesis of the C-glycoside analogue of -D-galactosyl-(5R,2S)-hydroxylysine (1) has been achieved starting from tetra-O-benzyl-D-galactopyranosyl lactone. The synthesis involved establishment of three stereogenic centers in an unambiguous manner. A facially selective Grignard reaction followed by a silane reduction was used for the anomeric position of the C-galactose residue. An Evans allylation established the configuration of the -aminomethylene group of the hydroxylysine moiety, whereas an asymmetric hydrogenation utilizing Burk's catalyst was used for the -amino acid moiety itself. The synthesis was completed in 17 steps with an overall yield of 18%, resulting in the most complex and functionalized C-glycoside analogue of a naturally occurring glycosylated amino acid prepared to date. In addition, amino acid 1 was incorporated in a glycopeptide from type II collagen known to be crucial for the response of autoimmune T cells obtained in models of rheumatoid arthritis. A preliminary immunological study revealed that four out of five members in a panel of T cell hybridomas were able to recognize this C-linked glycopeptide when presented by Aq class II MHC molecules.

  • 10.
    Hedenström, Mattias
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Kemi.
    NMR as a tool in drug research: Structure elucidation of peptidomimetics and pilicide-chaperone complexes2004Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    In the last decades NMR spectroscopy has become an invaluable tool both in academic research and in the pharmaceutical industry. This thesis describes applications of NMR spectroscopy in biomedicinal research for structure elucidation of biologically active peptides and peptidomimetics as well as in studies of ligand-protein interactions.

    The first part of this thesis describes the theory and methodology of structure calculations of peptides using experimental restraints derived from NMR spectroscopy. This methodology has been applied to novel mimetics of the peptide hormones desmopressin and Leu-enkephalin. The results of these studies highlight the complicating issue of conformational exchange often encountered in structural determination of peptides and how careful analysis of experimental data as well as optimization of experimental conditions can enable structure determinations in such instances. Although the mimetics of both desmopressin and Leu-enkephalin were found to adopt the wanted conformations, they exhibited no or very poor biological activity. These results demonstrate the difficulties in designing peptidomimetics without detailed structural information of the receptors. A stereoselective synthetic route towards XxxΨ[CH2O]Ala pseudodipeptides is also presented. Such pseudodipeptides can be used as isosteric amide bond replacements in peptides in order to increase their resistance towards proteolytic degradation.

    The second part of this thesis describes the study of the interaction between compounds that inhibit pilius assembly, pilicides, and periplasmic chaperones from uropathogenic Escherichia coli. Periplasmic chaperones are key components in assembly of pili, i.e. hair-like protein complexes located on the surface of Escherichia coli that cause urinary tract infections. Detailed knowledge about this interaction is important in understanding how pilicides can inhibit pilus assembly by binding to chaperones. Relaxation-edited NMR experiments were used to confirm the affinity of the pilicides for the chaperones and chemical shift mapping was used to study the pilicide-chaperone interaction surface. These studies show that at least two interaction sites are present on the chaperone surface and consequently that two different mechanisms resulting in inhibition of pilus assembly may exist.

  • 11.
    Hedenström, Mattias
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Emtenäs, Hans
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Pemberton, Nils
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Åberg, Veronica
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Hultgren, Scott J.
    Pinkner, Jerome S.
    Tegman, Viola
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Almqvist, Fredrik
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Sethson, Ingmar
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Kihlberg, Jan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    NMR studies of interactions between periplasmic chaperones from uropathogenic E-coli and pilicides that interfere with chaperone function and pilus assembly2005Ingår i: ORGANIC & BIOMOLECULAR CHEMISTRY, ISSN 1477-0520, Vol. 3, nr 23, s. 4193-4200Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Adherence of uropathogenic Escherichia coli to host tissue is mediated by pili, which are hair-like protein structures extending from the outer cell membrane of the bacterium. The chaperones FimC and PapD are key components in pilus assembly since they catalyse folding of subunits that are incorporated in type 1 and P pili, respectively, and also transport the subunits across the periplasmic space. Recently, compounds that inhibit pilus biogenesis and interfere with chaperone-subunit interactions have been discovered and termed pilicides. In this paper NMR spectroscopy was used to study the interaction of different pilicides with PapD and FimC in order to gain structural knowledge that would explain the effect that some pilicides have on pilus assembly. First relaxation-edited NMR experiments revealed that the pilicides bound to the PapD chaperone with mM affinity. Then the pilicide-chaperone interaction surface was investigated through chemical shift mapping using N-15-labelled FimC. Principal component analysis performed on the chemical shift perturbation data revealed the presence of three binding sites on the surface of FimC, which interacted with three different classes of pilicides. Analysis of structure-activity relationships suggested that pilicides reduce pilus assembly in E. coli either by binding in the cleft of the chaperone, or by influencing the orientation of the flexible F1-G1 loop, both of which are part of the surface by which the chaperone forms complexes with pilus subunits. It is suggested that binding to either of these sites interferes with folding of the pilus subunits, which occurs during formation of the chaperone-subunit complexes. In addition, pilicides that influence the F1-G1 loop also appear to reduce pilus formation by their ability to dissociate chaperone-subunit complexes.

  • 12.
    Hedenström, Mattias
    et al.
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Kemi.
    Holm, Lotta
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Kemi.
    Yuan, ZhongQing
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Kemi.
    Emtenäs, Hans
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Kemi.
    Kihlberg, Jan
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Kemi.
    Stereoselective Synthesis of Ψ[CH2O] Pseudodipeptides and Conformational Analysis of a PheΨ[CH2O]Ala Containing Analogue of the Drug Desmopressin2002Ingår i: Bioorganic & Medicinal Chemistry Letters, Vol. 12, nr 6, s. 841-4Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A method for synthesis of XaaΨ[CH2O]Ala/Gly pseudodipeptides in good yields and excellent diastereoselectivity from azido alcohols and (R)-2-chloropropionic acid or tert-butyl bromoacetate has been developed. Insertion of one of the pseudodipeptide building blocks in the peptide drug desmopressin revealed that methylene ether isosteres may have only a minor influence on the secondary structure of peptides.

  • 13.
    Hedenström, Mattias
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Wiklund, Susanne
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Sundberg, B
    Edlund, Ulf
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Visualization and interpretation of OPLS models based on 2D NMR DataArtikel i tidskrift (Refereegranskat)
  • 14.
    Hedenström, Mattias
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Wiklund, Susanne
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Sundberg, Björn
    Edlund, Ulf
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Visualization and interpretation of OPLS models based on 2D NMR data2008Ingår i: Chemometrics and Intelligent Laboratory Systems,, Vol. 92, nr 2, s. 110-7Artikel i tidskrift (Refereegranskat)
    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.

  • 15.
    Hedenström, Mattias
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Wiklund-Lindström, Susanne
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Öman, Tommy
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Lu, Fachuang
    Gerber, Lorenz
    Schatz, Paul
    Sundberg, Björn
    Ralph, John
    Identification of lignin and polysaccharide modifications in Populus wood by chemometric analysis of 2D NMR spectra from dissolved cell walls2009Ingår i: Molecular Plant, ISSN 1674-2052, Vol. 2, nr 5, s. 933-942Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    2D (13)C-(1)H HSQC NMR spectroscopy of acetylated cell walls in solution gives a detailed fingerprint that can be used to assess the chemical composition of the complete wall without extensive degradation. We demonstrate how multivariate analysis of such spectra can be used to visualize cell wall changes between sample types as high-resolution 2D NMR loading spectra. Changes in composition and structure for both lignin and polysaccharides can subsequently be interpreted on a molecular level. The multivariate approach alleviates problems associated with peak picking of overlapping peaks, and it allows the deduction of the relative importance of each peak for sample discrimination. As a first proof of concept, we compare Populus tension wood to normal wood. All well established differences in cellulose, hemicellulose, and lignin compositions between these wood types were readily detected, confirming the reliability of the multivariate approach. In a second example, wood from transgenic Populus modified in their degree of pectin methylesterification was compared to that of wild-type trees. We show that differences in both lignin and polysaccharide composition that are difficult to detect with traditional spectral analysis and that could not be a priori predicted were revealed by the multivariate approach. 2D NMR of dissolved cell wall samples combined with multivariate analysis constitutes a novel approach in cell wall analysis and provides a new tool that will benefit cell wall research.

  • 16.
    Hedenström, Mattias
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Wågberg, Thomas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Johnels, Dan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Characterization of Hydrogenated Fullerenes by NMR Spectroscopy2010Ingår i: Fulleranes: The Hydrogenated Fullerenes / [ed] Franco Cataldo, Susana Iglesias-Groth, Dordrecht: Springer Netherlands, 2010, Vol. 2, s. 171-202Kapitel i bok, del av antologi (Övrigt vetenskapligt)
    Abstract [en]

    NMR spectroscopy is so far the only analytical technique that has been used to get a detailed structural characterization of hydrogenated fullerenes. A substantial amount of information derived from different NMR experiments can thus be found in the literature for a number of fullerenes hydrogenated to various degrees. These studies have benefitted from the fact that chemical shifts of H-1 and C-13 and in some cases also He-3 can be used to obtain structural information of these compounds. Such results, together with discussions about different NMR experiments and general considerations regarding sample preparations, are summarized in this chapter. The unique information, both structural and physicochemical, that can be derived from different NMR experiments ensures that this technique will continue to be of central importance in characterization of hydrogenated fullerenes.

  • 17.
    Hedenström, Mattias
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Yuan, ZhongQing
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Brickmann, Kay
    Carlsson, Jolanta
    Ekholm, Kjell
    Johansson, Birgitta
    Kreutz, Eva
    Nilsson, Anders
    Sethson, Ingmar
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Kihlberg, Jan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Conformations and Receptor Activity of Desmopressin Analogues, Which Contain -Turn Mimetics or a [CH2O] Isostere2002Ingår i: Journal of Medicinal Chemistry, Vol. 45, nr 12, s. 2501-11Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Three analogues of the antidiuretic drug desmopressin ([1-desamino,8-D-arginine]vasopressin) have been prepared. In two of these, -turn mimetics based on a morpholin-3-one framework have been inserted instead of residues Phe3-Asn5, whereas the third analogue has a methylene ether isostere in place of the amide bond between residues 3 and 4. The three analogues were used to probe if the structure determined for desmopressin in aqueous solution, which contains an inverse -turn centered around Gln4, is important in interactions with the vasopressin V2 receptor. Conformational studies revealed that the analogues that contain either an inverse -turn mimetic or a methylene ether isostere mimicked the conformation of desmopressin fairly well and very well, respectively. Despite this, the analogues displayed only very low agonistic activities at the vasopressin V2 receptor. Consequently, an inverse -turn involving residues Phe3-Asn5 does not appear to be important when desmopressin is bound to the V2 receptor. In addition, it was concluded that the amide bond between Phe3 and Gln4 in desmopressin is crucial for interactions with the antidiuretic V2 receptor.

  • 18.
    Jogunola, Olatunde
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Eta, Valerie
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Laboratory of Industrial Chemistry and Reaction Engineering, Johan Gadolin Process Chemistry Centre, Åbo Akademi University, 20500 Åbo/Turku, Finland.
    Hedenström, Mattias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Sundman, Ola
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Salmi, Tapio
    Mikkola, Jyri-Pekka
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Laboratory of Industrial Chemistry and Reaction Engineering, Johan Gadolin Process Chemistry Centre, Åbo Akademi University, 20500 Åbo/Turku, Finland.
    Ionic liquid mediated technology for synthesis of cellulose acetates using different co-solvents2016Ingår i: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 135, s. 341-348Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this work, cellulose acetate was synthesized under homogeneous conditions. Cellulose was first dispersed in acetone, acetonitrile, 1,5-diazabicyclo(4.3.0)non-5-ene (DBN) or dimethyl sulphoxide (DMSO) and the resulting suspension was dissolved in an ionic liquid, 1,5-diazabicyclo(4.3.0)non-5-enium acetate [HDBN][OAc] at 70 °C for 0.5 h. It was possible to dissolve more than 12 wt% cellulose with a degree of polymerization in the range of 1000–1100. The dissolved cellulose was derivatized with acetic anhydride (Ac2O) to yield acetylated cellulose. As expected, the use of the co-solvents improved the acetylation process significantly. In fact, cellulose acetates with different properties could be obtained in half an hour, thus facilitating rapid processing. When DBN was used as the dispersing agent (the precursor of the ionic liquid), the problems associated with recycling of the ionic liquid were significantly reduced. In fact, additional [HDBN][OAc] was obtained from the interaction of the DBN and the by-product, acetic acid (from Ac2O). However, the cellulose acetate obtained in this manner had the lowest DS. Consequently, the native cellulose and acetylated celluloses were characterized by means of 1H- and 13C-NMR, FT-IR, GPC/SEC and by titration. The cellulose acetates produced were soluble in organic solvents such as acetone, chloroform, dichloromethane and DMSO which is essential for their further processing. It was demonstrated that the ionic liquid can be recovered from the system by distillation and re-used in consecutive acetylation batches.

  • 19.
    Karlsson, Göran
    et al.
    Swedish NMR Centre at the University of Gothenburg.
    Persson, Cecilia
    Swedish NMR Centre at the University of Gothenburg.
    Mayzel, Maxim
    Swedish NMR Centre at the University of Gothenburg.
    Hedenström, Mattias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Backman, Lars
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Solution structure of the calmodulin-like C-terminal domain of Entamoeba α-actinin22016Ingår i: Proteins: Structure, Function, and Bioinformatics, ISSN 0887-3585, E-ISSN 1097-0134, Vol. 84, nr 4, s. 461-466Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Cell motility is dependent on a dynamic meshwork of actin filaments that is remodelled continuously. A large number of associated proteins that are severs, cross-links, or caps the filament ends have been identified and the actin cross-linker α-actinin has been implied in several important cellular processes. In Entamoeba histolytica, the etiological agent of human amoebiasis, α-actinin is believed to be required for infection. To better understand the role of α-actinin in the infectious process we have determined the solution structure of the C-terminal calmodulin-like domain using NMR. The final stru-ture ensemble of the apo form shows two lobes, that both resemble other pairs of calcium-binding EF-hand motifs, connected with a mobile linker.

  • 20. Laera, Andreina
    et al.
    Yekta, Sepehr Shakeri
    Hedenström, Mattias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Buzier, Remy
    Guibaud, Gilles
    Dario, Mårten
    Esposito, Giovanni
    van Hullebusch, Eric D.
    A simultaneous assessment of organic matter and trace elements bio-accessibility in substrate and digestate from an anaerobic digestion plant2019Ingår i: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 288, artikel-id 121587Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study evaluates a simultaneous assessment of organic matter (OM) and trace elements (TE) bio-accessibility in substrate and digestate from a full-scale anaerobic digester by a sequential OM extraction method. Simultaneous release of TE was determined along with the extraction of different OM fractions and the effects of extracting reagents on characteristics of OM were evaluated by nuclear magnetic resonance (NMR) spectroscopy. The reagents used for sequential extraction of OM were not enough selective. However, proteins were particularly removed by 0.1 M NaOH, while 72% H2SO4 mainly extracted hemicellulose and cellulose. The OM fractionation allowed for simultaneous extraction of > 60% of total As, Cd, Co, Fe, Mn, Ni and Zn, while the extraction was limited for Al, Cr, Cu, Mo, and Pb. In substrate, > 50% of total As, Co, Mn and Ni and < 40% of total Fe, Zn and Mo were identified in bio-accessible fractions. In digestate, all elements demonstrated poor bio-accessibility except for As.

  • 21.
    Livendahl, Madeleine
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Jamroskovic, Jan
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk kemi och biofysik.
    Hedenström, Mattias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Görlich, T.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Sabouri, Nasim
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk kemi och biofysik.
    Chorell, Erik
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Synthesis of phenanthridine spiropyrans and studies of their effects on G-quadruplex DNA2017Ingår i: Organic and biomolecular chemistry, ISSN 1477-0520, E-ISSN 1477-0539, Vol. 15, nr 15, s. 3265-3275Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    G-quadruplex (G4) DNA structures are involved in many important biological processes and can be linked to several human diseases. Drug-like low molecular weight compounds that target G4 structures are therefore interesting not only for their potential therapeutic properties but also for their potential use as chemical research tools. We report here on the development of methods to synthesize spiropyrans using a condensation-cyclisation reaction of quaternary salts of [small alpha]-methyl quinoline or phenanthridine with salicylaldehydes. Evaluation of the synthesized phenanthridine spiropyrans' interactions with G4 DNA was performed with a Thioflavin T displacement assay, circular dichroism, Taq DNA polymerase stop assay, and NMR. This revealed that the substitution pattern on the phenanthridine spiropyrans was very important for their ability to bind and stabilize G4 structures. Some of the synthesized low molecular weight spirocyclic compounds efficiently stabilized G4 structures without inducing structural changes by binding the first G-tetrad in the G4 structure.

  • 22.
    Lundstedt, Torbjörn
    et al.
    AcurePharma AB, Uppsala, Sweden.
    Hedenström, Mattias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Soeria-Atmadja, D
    Division of Toxicology, National Food Administration, Uppsala, Sweden.
    Hammerling, U
    Division of Toxicology, National Food Administration, Uppsala, Sweden.
    Gabrielsson, Jon
    AcureOmics AB, Umeå, Sweden.
    Olsson, J
    KPL Good Food Practice AB, Uppsala, Sweden.
    Trygg, Johan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Dynamic modelling of time series data in nutritional metabonomics: A powerful complement to randomized clinical trials in functional food studies2010Ingår i: Chemometrics and Intelligent Laboratory Systems, ISSN 0169-7439, E-ISSN 1873-3239, Vol. 104, nr 1, s. 112-120Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Functional foods are foods or dietary ingredients that provide a health benefit beyond basic nutrition. A new legislation, known as the Nutrition and Health Claims Regulation, defines the legal framework for such claims within the European Union. Any claim about the nutritional or physiological effects of a product must be scientifically demonstrated. In this study, we have focused on the exploration of metabonomics as a complementary profiling technology to establish monitoring/data analysis procedures of randomized nutritional trials. More specifically, a combined intake of soybean and grapefruit in a human intervention study was analyzed with respect to both pharmacological and physiological effects. Resulting multivariate models showed a diet-induced decrease of lactate, cholesterols and triglycerides. The most drastically elevated metabolite, myo-inositol, was found to accompany a marked reduction of triglyceride levels. Suggestively, this is due to the biotransformation of myo-inositol to phosphatidylinositol, which results in a decrease of available precursors to form triglycerides. Strong inter-subject variation was present that required special attention. Dynamic modelling of collected time series data that provided the opportunity to identify slow, medium or fast responders as well as groups of subjects showing different response profiles, was also highlighted in the study. The applied strategy of time series data has proven to be a powerful complement to randomized nutritional studies adopting a clinical trial design.

  • 23. Mahboubi, Amir
    et al.
    Linden, Pernilla
    Hedenström, Mattias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Moritz, Thomas
    Niittyla, Totte
    C-13 Tracking after (CO2)-C-13 Supply Revealed Diurnal Patterns of Wood Formation in Aspen2015Ingår i: Plant Physiology, ISSN 0032-0889, E-ISSN 1532-2548, Vol. 168, nr 2, s. 478-489Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Wood of trees is formed from carbon assimilated in the photosynthetic tissues. Determining the temporal dynamics of carbon assimilation, subsequent transport into developing wood, and incorporation to cell walls would further our understanding of wood formation in particular and tree growth in general. To investigate these questions, we designed a (CO2)-C-13 labeling system to study carbon transport and incorporation to developing wood of hybrid aspen (Populus tremula 3 tremuloides). Tracking of C-13 incorporation to wood over a time course using nuclear magnetic resonance spectroscopy revealed diurnal patterns in wood cell wall biosynthesis. The dark period had a differential effect on C-13 incorporation to lignin and cell wall carbohydrates. No C-13 was incorporated into aromatic amino acids of cell wall proteins in the dark, suggesting that cell wall protein biosynthesis ceased during the night. The results show previously unrecognized temporal patterns in wood cell wall biosynthesis, suggest diurnal cycle as a possible cue in the regulation of carbon incorporation to wood, and establish a unique C-13 labeling method for the analysis of wood formation and secondary growth in trees.

  • 24.
    Mercier, Guillaume
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Klechikov, Alexey
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Hedenstrom, Mattias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Johnels, Dan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Baburin, Igor A.
    Seifert, Gotthard
    Mysyk, Roman
    Talyzin, Alexandr V.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Porous Graphene Oxide/Diboronic Acid Materials: Structure and Hydrogen Sorption2015Ingår i: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 119, nr 49, s. 27179-27191Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Solvothermal reaction of graphite oxide (GO) with benzene-1,4-diboronic acid (DBA) was reported previously to result in formation of graphene oxide framework (GOP) materials. The theoretical structure of GOFs consists of graphene layers separated by benzene-diboronic "pillars" with similar to 1 nm slit pores thus providing the opportunity to use it as a model material to verify the effect of a small pore size on hydrogen adsorption. A set of samples with specific surface area (SSA) in the range of similar to 50-1000 m(2)/g were prepared using variations of synthesis conditions and GO/DBA proportions. Hydrogen storage properties of GOF samples evaluated at 293 and 77 K were found to be similar to other nanocarbon trends in relation to SSA values. Structural characterization of GO/DBA samples showed all typical features reported as evidence for formation of a framework structure such as expanded interlayer distance, increased temperature of thermal exfoliation, typical features in FTIR spectra, etc. However, the samples also exhibited reversible swelling in polar solvents which is not compatible with the idealized GOF structure linked by benzenediboronic molecular pillars. Therefore, possible alternative nonframework models of structures with pillars parallel and perpendicular to GO planes are considered.

  • 25. Michel, Maurice
    et al.
    Visnes, Torkild
    Homan, Evert J.
    Seashore-Ludlow, Brinton
    Hedenström, Mattias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Wiita, Elisee
    Vallin, Karl
    Paulin, Cynthia B. J.
    Zhang, Jiaxi
    Wallner, Olov
    Scobie, Martin
    Schmidt, Andreas
    Jenmalm-Jensen, Annika
    Berglund, Ulrika Warpman
    Helleday, Thomas
    Computational and Experimental Druggability Assessment of Human DNA Glycosylases2019Ingår i: ACS OMEGA, ISSN 2470-1343, Vol. 4, nr 7, s. 11642-11656Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Due to a polar or even charged binding interface, DNA-binding proteins are considered extraordinarily difficult targets for development of small-molecule ligands and only a handful of proteins have been targeted successfully to date. Recently, however, it has been shown that development of selective and efficient inhibitors of 8-oxoguanine DNA glycosylase is possible. Here, we describe the initial druggability assessment of DNA glycosylases in a computational setting and experimentally investigate several methods to target endonuclease VIII-like 1 (NEIL1) with small-molecule inhibitors. We find that DNA glycosylases exhibit good predicted druggability in both DNA-bound and -unbound states. Furthermore, we find catalytic sites to be highly flexible, allowing for a range of interactions and binding partners. One flexible catalytic site was rationalized for NEIL1 and further investigated experimentally using both a biochemical assay in the presence of DNA and a thermal shift assay in the absence of DNA.

  • 26.
    Mojica, Sergio A.
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi.
    Salin, Olli
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi.
    Bastidas, Robert J.
    Sunduru, Naresh
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Hedenström, Mattias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Andersson, C. David
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Núñez-Otero, Carlos
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi.
    Engström, Patrik
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för molekylärbiologi (Teknisk-naturvetenskaplig fakultet).
    Valdivia, Raphael H.
    Elofsson, Mikael
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Umeå universitet, Medicinska fakulteten, Molekylär Infektionsmedicin, Sverige (MIMS). Umeå universitet, Medicinska fakulteten, Umeå Centre for Microbial Research (UCMR).
    Gylfe, Åsa
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi. Umeå universitet, Medicinska fakulteten, Molekylär Infektionsmedicin, Sverige (MIMS). Umeå universitet, Medicinska fakulteten, Umeå Centre for Microbial Research (UCMR).
    N-acylated derivatives of sulfamethoxazole block Chlamydia fatty acid synthesis and interact with FabF2017Ingår i: Antimicrobial Agents and Chemotherapy, ISSN 0066-4804, E-ISSN 1098-6596, Vol. 61, nr 10, artikel-id e00716-17Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The type II fatty acid synthesis (FASII) pathway is essential for bacterial lipid biosynthesis and continues to be a promising target for novel antibacterial compounds. Recently, it has been demonstrated that Chlamydia is capable of FASII and this pathway is indispensable for Chlamydia growth. Previously, a high-content screen with Chlamydia trachomatis-infected cells was performed, and acylated sulfonamides were identified to be potent growth inhibitors of the bacteria. C. trachomatis strains resistant to acylated sulfonamides were isolated by serial passage of a wild-type strain in the presence of low compound concentrations. Results from whole-genome sequencing of 10 isolates from two independent drug-resistant populations revealed that mutations that accumulated in fabF were predominant. Studies of the interaction between the FabF protein and small molecules showed that acylated sulfonamides directly bind to recombinant FabF in vitro and treatment of C. trachomatis-infected HeLa cells with the compounds leads to a decrease in the synthesis of Chlamydia fatty acids. This work demonstrates the importance of FASII for Chlamydia development and may lead to the development of new antimicrobials.

  • 27.
    Nilsson, Emma C
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Virologi.
    Storm, Rickard J
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Virologi.
    Bauer, Johannes
    University of Tübingen.
    Johansson, Susanne M C
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Virologi.
    Lookene, Aivar
    Tallinn University of Technology, Tallinn, Estonia..
    Ångström, Jonas
    University of Göteborg.
    Hedenström, Mattias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Eriksson, Therese L
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Virologi.
    Frängsmyr, Lars
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Virologi.
    Rinaldi, Simon
    University of Glasgow.
    Willison, Hugh J
    University of Glasgow.
    Domellöf, Fatima Pedrosa
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk vetenskap, Oftalmiatrik. Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi.
    Stehle, Thilo
    University of Tübingen, Vanderbilt University School of Medicine.
    Arnberg, Niklas
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Virologi. Umeå universitet, Medicinska fakulteten, Molekylär Infektionsmedicin, Sverige (MIMS).
    The GD1a glycan is a cellular receptor for adenoviruses causing epidemic keratoconjunctivitis (Letter)2011Ingår i: Nature Medicine, ISSN 1078-8956, E-ISSN 1546-170X, Vol. 17, nr 1, s. 105-109Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Adenovirus type 37 (Ad37) is a leading cause of epidemic keratoconjunctivitis (EKC), a severe and highly contagious ocular disease. Whereas most other adenoviruses infect cells by engaging CD46 or the coxsackie and adenovirus receptor (CAR), Ad37 binds previously unknown sialic acid-containing cell surface molecules. By glycan array screening, we show here that the receptor-recognizing knob domain of the Ad37 fiber protein specifically binds a branched hexasaccharide that is present in the GD1a ganglioside and that features two terminal sialic acids. Soluble GD1a glycan and GD1a-binding antibodies efficiently prevented Ad37 virions from binding and infecting corneal cells. Unexpectedly, the receptor is constituted by one or more glycoproteins containing the GD1a glycan motif rather than the ganglioside itself, as shown by binding, infection and flow cytometry experiments. Molecular modeling, nuclear magnetic resonance and X-ray crystallography reveal that the two terminal sialic acids dock into two of three previously established sialic acid-binding sites in the trimeric Ad37 knob. Surface plasmon resonance analysis shows that the knob-GD1a glycan interaction has high affinity. Our findings therefore form a basis for the design and development of sialic acid-containing antiviral drugs for topical treatment of EKC.

  • 28.
    Normark, Monica
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Pommer, Linda
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Gräsvik, John
    Hedenström, Mattias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Gorzsas, Andras
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Winestrand, Sandra
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Jönsson, Leif J.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Biochemical Conversion of Torrefied Norway Spruce After Pretreatment with Acid or Ionic Liquid2016Ingår i: Bioenergy Research, ISSN 1939-1234, E-ISSN 1939-1242, Vol. 9, nr 1, s. 355-368Artikel i tidskrift (Refereegranskat)
    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.

  • 29. Pawar, Prashant Mohan-Anupama
    et al.
    Derba-Maceluch, Marta
    Chong, Sun-Li
    Gandla, Madhavi Latha
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Bashar, Shamrat Shafiul
    Sparrman, Tobias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Ahvenainen, Patrik
    Hedenström, Mattias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Ozparpucu, Merve
    Ruggeberg, Markus
    Serimaa, Ritva
    Lawoko, Martin
    Tenkanen, Maija
    Jönsson, Leif J.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Mellerowicz, Ewa J.
    In muro deacetylation of xylan affects lignin properties and improves saccharification of aspen wood2017Ingår i: Biotechnology for Biofuels, ISSN 1754-6834, E-ISSN 1754-6834, Vol. 10, artikel-id 98Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: Lignocellulose from fast growing hardwood species is a preferred source of polysaccharides for advanced biofuels and “green” chemicals. However, the extensive acetylation of hardwood xylan hinders lignocellulose saccharification by obstructing enzymatic xylan hydrolysis and causing inhibitory acetic acid concentrations during microbial sugar fermentation. To optimize lignocellulose for cost-effective saccharification and biofuel production, an acetyl xylan esterase AnAXE1 from Aspergillus niger was introduced into aspen and targeted to cell walls.

    Results: AnAXE1-expressing plants exhibited reduced xylan acetylation and grew normally. Without pretreatment, their lignocellulose yielded over 25% more glucose per unit mass of wood (dry weight) than wild-type plants. Glucose yields were less improved (+7%) after acid pretreatment, which hydrolyses xylan. The results indicate that AnAXE1 expression also reduced the molecular weight of xylan, and xylan–lignin complexes and/or lignin co-extracted with xylan, increased cellulose crystallinity, altered the lignin composition, reducing its syringyl to guaiacyl ratio, and increased lignin solubility in dioxane and hot water. Lignin-associated carbohydrates became enriched in xylose residues, indicating a higher content of xylo-oligosaccharides.

    Conclusions: This work revealed several changes in plant cell walls caused by deacetylation of xylan. We propose that deacetylated xylan is partially hydrolyzed in the cell walls, liberating xylo-oligosaccharides and their associated lignin oligomers from the cell wall network. Deacetylating xylan thus not only increases its susceptibility to hydrolytic enzymes during saccharification but also changes the cell wall architecture, increasing the extractability of lignin and xylan and facilitating saccharification.

  • 30. Pawar, Prashant Mohan-Anupama
    et al.
    Ratke, Christine
    Balasubramanian, Vimal K.
    Chong, Sun-Li
    Gandla, Madhavi Latha
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Adriasola, Mathilda
    Sparrman, Tobias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Hedenstrom, Mattias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Szwaj, Klaudia
    Derba-Maceluch, Marta
    Gaertner, Cyril
    Mouille, Gregory
    Ezcurra, Ines
    Tenkanen, Maija
    Jonsson, Leif J.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Mellerowicz, Ewa J.
    Downregulation of RWA genes in hybrid aspen affects xylan acetylation and wood saccharification2017Ingår i: New Phytologist, ISSN 0028-646X, E-ISSN 1469-8137, Vol. 214, s. 1491-1505Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    High acetylation of angiosperm wood hinders its conversion to sugars by glycoside hydrolases, subsequent ethanol fermentation and (hence) its use for biofuel production. We studied the REDUCED WALL ACETYLATION (RWA) gene family of the hardwood model Populus to evaluate its potential for improving saccharification. The family has two clades, AB and CD, containing two genes each. All four genes are expressed in developing wood but only RWA-A and -B are activated by master switches of the secondary cell wall PtNST1 and PtMYB21. Histochemical analysis of promoter:: GUS lines in hybrid aspen (Populus tremula x tremuloides) showed activation of RWA-A and -B promoters in the secondary wall formation zone, while RWA-C and -D promoter activity was diffuse. Ectopic downregulation of either clade reduced wood xylan and xyloglucan acetylation. Suppressing both clades simultaneously using the wood-specific promoter reduced wood acetylation by 25% and decreased acetylation at position 2 of Xylp in the dimethyl sulfoxide-extracted xylan. This did not affect plant growth but decreased xylose and increased glucose contents in the noncellulosic monosaccharide fraction, and increased glucose and xylose yields of wood enzymatic hydrolysis without pretreatment. Both RWA clades regulate wood xylan acetylation in aspen and are promising targets to improve wood saccharification.

  • 31. Pinkner, Jerome S.
    et al.
    Remaut, Han
    Buelens, Floris
    Miller, Eric
    Åberg, Veronica
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Pemberton, Nils
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Hedenström, Mattias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Larsson, Andreas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Seed, Patrick
    Waksman, Gabriel
    Hultgren, Scott J.
    Almqvist, Fredrik
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Rationally designed small compounds inhibit pilus biogenesis in uropathogenic bacteria2006Ingår i: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 103, nr 47, s. 17897-17902Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A chemical synthesis platform with broad applications and flexibility was rationally designed to inhibit biogenesis of adhesive pili assembled by the chaperone–usher pathway in Gram-negative pathogens. The activity of a family of bicyclic 2-pyridones, termed pilicides, was evaluated in two different pilus biogenesis systems in uropathogenic Escherichia coli. Hemagglutination mediated by either type 1 or P pili, adherence to bladder cells, and biofilm formation mediated by type 1 pili were all reduced by 90% in laboratory and clinical E. coli strains. The structure of the pilicide bound to the P pilus chaperone PapD revealed that the pilicide bound to the surface of the chaperone known to interact with the usher, the outer-membrane assembly platform where pili are assembled. Point mutations in the pilicide-binding site dramatically reduced pilus formation but did not block the ability of PapD to bind subunits and mediate their folding. Surface plasmon resonance experiments confirmed that the pilicide interfered with the binding of chaperone–subunit complexes to the usher. These pilicides thus target key virulence factors in pathogenic bacteria and represent a promising proof of concept for developing drugs that function by targeting virulence factors.

  • 32.
    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 universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    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 wood2012Ingår i: The Plant Journal, ISSN 0960-7412, E-ISSN 1365-313X, Vol. 70, nr 6, s. 967-977Artikel i tidskrift (Refereegranskat)
    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.

  • 33.
    Strunk, Peter
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Öman, Tommy
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Gorzsás, András
    Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences (SLU), Umeå, Sweden.
    Hedenström, Mattias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Eliasson, Bertil
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Characterization of dissolving pulp by multivariate data analysis of FT-IR and NMR spectra2011Ingår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 26, nr 4, s. 398-409Artikel i tidskrift (Refereegranskat)
    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.

  • 34.
    Svensson, Anette
    et al.
    Organic Chemistry 2 Center for Chemistry and Chemical Engineering Lund Institute of Technology, Lund University P.O. Box 124, SE-221 00 Lund, Sweden.
    Larsson, Andreas
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Kemi.
    Emtenäs, Hans
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Kemi.
    Hedenström, Mattias
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Kemi.
    Fex, Tomas
    3Active Biotech, Lund Research Center P.O. Box 724, SE-220 07 Lund, Sweden.
    Hultgren, Scott J.
    Department of Molecular Microbiology Washington University School of Medicine 660 South Euclid Avenue, St. Louis, MO 63110, USA.
    Pinker, Jerome S.
    Department of Molecular Microbiology Washington University School of Medicine 660 South Euclid Avenue, St. Louis, MO 63110, USA.
    Almqvist, Fredrik
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Kemi.
    Kihlberg, Jan
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Kemi.
    Design and evaluation of Pilicides: Potential novel antibacterial agents directed against Uropathogenic Escherichia coli2001Ingår i: ChemBioChem (Print), ISSN 1439-4227, E-ISSN 1439-7633, ChemBioChem (Online), ISSN '1439-7633', Vol. 2, nr 12, s. 915-918Artikel i tidskrift (Refereegranskat)
  • 35. Takahashi, Junko
    et al.
    Rudsander, Ulla J
    Hedenström, Mattias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Banasiak, Alicja
    Harholt, Jesper
    Amelot, Nicolas
    Immerzeel, Peter
    Ryden, Peter
    Endo, Satoshi
    Ibatullin, Farid M
    Brumer, Harry
    del Campillo, Elena
    Master, Emma R.
    Scheller, Henrik Vibe
    Sundberg, Björn
    Teeri, Tuula T
    Mellerowicz, Ewa J
    KORRIGAN1 and its Aspen Homolog PttCel9A1 Decrease Cellulose Crystallinity in Arabidopsis Stems2009Ingår i: Plant and Cell Physiology, ISSN 0032-0781, E-ISSN 1471-9053, Vol. 50, nr 6, s. 1099-1115Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    KORRIGAN1 (KOR1) is a membrane-bound cellulase implicated incellulose biosynthesis. PttCel9A1 from hybrid aspen (Populustremula L. x tremuloides Michx.) has high sequence similarityto KOR1 and we demonstrate here that it complements kor1-1 mutants,indicating that it is a KOR1 ortholog. We investigated the functionof PttCel9A1/KOR1 in Arabidopsis secondary growth using transgeniclines expressing 35S::PttCel9A1 and the KOR1 mutant line irx2-2.The presence of elevated levels of PttCel9A1/KOR1 in secondarywalls of 35S::PttCel9A1 lines was confirmed by in muro visualizationof cellulase activity. Compared with the wild type, 35S::PttCel9A1lines had higher trifluoroacetic acid (TFA)-hydrolyzable glucancontents, similar Updegraff cellulose contents and lower cellulosecrystallinity indices, as determined by 13C solid-state nuclearmagnetic resonance (NMR) spectroscopy. irx2-2 mutants had wild-typeTFA-hydrolyzable glucan contents, but reduced Updegraff cellulosecontents and higher than wild-type cellulose crystallinity indices.The data support the hypothesis that PttCel9A1/KOR1 activityis present in cell walls, where it facilitates cellulose biosynthesisin a way that increases the amount of non-crystalline cellulose.

  • 36.
    Talyzin, Alexandr
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Mercier, Guillaume
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Klechikov, Alexey
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Hedenström, Mattias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Johnels, Dan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Wei, Di
    Cotton, Darryl
    Opitz, Andreas
    Moons, Ellen
    Brodie vs Hummers graphite oxides for preparation of multi-layered materials2017Ingår i: Carbon, ISSN 0008-6223, E-ISSN 1873-3891, Vol. 115, s. 430-440Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Graphite oxides synthesized by one and two step Brodie oxidation (BGO) and Hummers (HGO) methods were analyzed by a variety of characterization methods in order to evaluate the reasons behind the difference in their properties. It is found that the Brodie method results in a higher relative amount of hydroxyl groups and a more homogeneous overall distribution of functional groups over the planar surface of the graphene oxide flakes. The higher number of carbonyl and carboxyl groups in HGO, detected by several methods, including XPS, NMR and FTIR, unavoidably results in defects of the graphene "skeleton", holes and overall disruption of the carbon-carbon bond network, stronger deviation from planar flake shape and poor ordering of the graphene oxide layers. It is also suggested that functional groups in HGO are less homogeneously distributed over the flake surface, forming some nanometer-sized graphene areas. The presence of differently oxidized areas on the GO surface results in inhomogeneous solvation and hydration of HGO and effects of inter- and intra-stratification. The proposed interpretation of the data explains the higher mechanical strength of multi-layered BGO membranes/papers, which are also less affected by humidity changes, thus providing an example of a membrane property superior to that of HGO.

  • 37.
    Wang, Zhao
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Pawar, PM
    Derba-Maceluch, Marta
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysiologisk botanik.
    Hedenström, Mattias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Chong, Sun-Li
    Tenkanen, M
    Mellerowicz, E
    Jönsson, Leif J
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Bioprocessing properties of hybrid aspen expressing a Carbohydrate Esterase Family 5 acetyl xylan esterase under control of a wood-specific promoterManuskript (preprint) (Övrigt vetenskapligt)
  • 38.
    Wuolikainen, Anna
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Neurologi. Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Hedenström, Mattias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Moritz, Thomas
    Marklund, Stefan
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Klinisk kemi.
    Antti, Henrik
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Andersen, Peter
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Neurologi.
    Optimization of procedures for collecting and storing of CSF for studying the metabolome in ALS2009Ingår i: Amyotrophic Lateral Sclerosis, ISSN 1748-2968, Vol. 10, nr 4, s. 229-236Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    There is a need for biomarkers for early diagnosis, development and evaluation of treatment efficacy in amyotrophic lateral sclerosis (ALS). We aimed to investigate if pre-analytical factors induce artefacts in metabolomic data of cerebrospinal fluid (CSF) from patients with ALS. CSF from 16 patients was studied using a statistical experimental design protocol with the following parameters: storage temperature (-80 degrees C/ - 20 degrees C), type of collection tube (polypropylene/polystyrene), and time delay from collecting to freezing (0, 10, 30, 90, 150 min). Gas chromatography-mass spectrometry was used to analyse CSF from 12 of the patients while CSF from one patient was analysed with nuclear magnetic resonance spectroscopy. The extent of CO(2) evaporization from CSF collected in tubes of different sizes at different temperatures and with/without lid were studied in three addtional patients. We found that alterations in storage temperature affect the metabolite composition of CSF more than any other studied pre-analytical parameter. CO(2) evaporization may induce artefacts in the metabolome by increasing the pH. In conclusion, minimization of evaluated artefacts can be obtained by collecting the CSF directly into tubes with tightly sealed lids in N(2)(l) and after freezing transfer of the tubes to -80 degrees C to minimize evaporation of CO(2).

  • 39.
    Wågberg, Thomas
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Hedenström, Mattias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Talyzin, Alexandr V
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Sethson, Ingmar
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Tsybin, Yury O
    Purcell, Jeremiah M
    Marshall, Alan G
    Noréus, Dag
    Johnels, Dan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Synthesis and Structural Characterization of C70H382008Ingår i: Angewandte Chemie International Edition, Vol. 47, nr 15, s. 2796-9Artikel i tidskrift (Refereegranskat)
  • 40.
    Wågberg, Thomas
    et al.
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Fysik.
    Johnels, Dan
    Kemi.
    Peera, Ashgar
    Hedenström, Mattias
    Kemi.
    Shulga, Yury M.
    Tsybin, Yury O.
    Purcell, J.M.
    Marshall, Alan.G.
    Noreus, Dag
    Sato, Toyoto
    Talyzin, Alexandr V.
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Fysik.
    Selective synthesis of the C3v-isomer of C60H182005Ingår i: Organic Letters, ISSN 1523-7060, Vol. 7, nr 25, s. 5557-60Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    C60H18 has been produced by hydrogenation of C-60 at 100 bar H-2 pressure and 673 K for 10 h. We have investigated the crude material without any purification by use of H-1 NMR, C-13 NMR, and IR spectroscopy and Fourier transform ion cyclotron resonance mass spectrometry. We show that the crude material consists of 95% of the C-3v isomer of C60H18.

  • 41. Yekta, Sepehr Shakeri
    et al.
    Hedenström, Mattias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Stehr, Jan Eric
    Dario, Mårten
    Hertkorn, Norbert
    Björn, Annika
    Pretreatment of anaerobic digester samples by hydrochloric acid for solution-state H-1 and C-13 NMR spectroscopic characterization of organic matter2018Ingår i: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 199, s. 201-209Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Pretreatment of anaerobic digester samples by hydrochloric acid (HCl) resulted in removal of Fe-based mineral and coordination compounds, attenuating their interferences with solution-state nuclear magnetic resonance (NMR) spectroscopic characterization of the solid phase organic matter. Substrate (influent) and digestate (effluent) samples from two full-scale anaerobic digesters, designated CD (co-digester) and SSD (sewage sludge digester), were investigated. Pretreatment of CD samples with 0.2-2.0 mol l(-1) HCl and pretreatment of SSD samples with 1.0-3.0 mol l(-1) HCl removed 96-100% and 76-80% of total Fe, respectively. Pretreatment declined overall paramagnetic characteristics of digestate samples, manifested by 50% (CD) and 70% (SSD) decrease in electron paramagnetic resonance signal intensities. As a result, meaningful solution-state H-1,C-13 heteronuclear single quantum coherence and H-1 NMR spectra of DMSO-d(6) soluble organic matter could be acquired. Sample pretreatment with the lowest concentration of HCl resulted in alteration of C:N ratios in solid phase, likely due to removal of labile organic and inorganic C- and N-containing compounds, while elevating the HCl concentration did not further change the C:N ratios. Furthermore, sample pretreatment increased the solubility of carbohydrates and proteins in DMSO-d(6), enabling the detection of NMR resonances from certain structural units of carbohydrates (e.g. anomeric O2CH) and proteins (e.g. CH alpha in amino acids). Both attenuation of the paramagnetic matrix as well as art enhanced solubility of carbohydrate and protein fractions of the samples in DMSO-d(6) solvent contributed to an improved molecular characterization of anaerobic digester samples by solution-state NMR analysis. 

  • 42. Yekta, Sepehr Shakeri
    et al.
    Hedenström, Mattias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Svensson, Bo H.
    Sundgren, Ingrid
    Dario, Marten
    Enrich-Prast, Alex
    Hertkorn, Norbert
    Bjorn, Annika
    Molecular characterization of particulate organic matter in full scale anaerobic digesters: An NMR spectroscopy study2019Ingår i: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 685, s. 1107-1115Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study assesses the molecular characteristics of particulate organic matter (POM) in agricultural and food waste digesters and elucidates the molecular properties of the recalcitrant POM fraction, which remains in the digestate after AD process. Molecular properties of POM in influent (substrate) and effluent (digestate) of seven full-scale AD plants (three agricultural waste and four food waste digesters) were characterized and compared using solid-state (13)C( )cross-polarization magic angle spinning (CP-MAS) and solution-state H-1,C-13 heteronuclear single-quantum coherence (HSQC) nuclear magnetic resonance (NMR) spectroscopy. Comparison of the POM structural compositions of substrate and digestate from each AD plant revealed an enrichment of protein structures relative to the carbohydrates in most cases, implying a preferential degradation of the carbohydrates over proteins and/or increase of microbial biomass upon AD of agricultural and food wastes. Distinctive molecular structures of labile and recalcitrant fractions of POM, subjected to AD, were identified by comparing the NMR spectra of all substrate and digestate POM. Accordingly, the labile POM fraction in food and agricultural solid wastes is characterized by structural entities of lipids and starch-like carbohydrates, whereas recalcitrant POM structures resemble alkyl and aromatic subunits of amino acids, lignin, and polysaccharides with beta-glycosidic linkages. This information serves as a basis to further explore optimization approaches for improving AD of the underutilized POM and the fate of organic matter in digestate-amended arable lands. (C) 2018 The Authors. Published by Elsevier B.V.

  • 43.
    Åberg, Veronica
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Das, Pralay
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Chorell, Erik
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Hedenström, Mattias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Pinkner, Jerome S
    Molecular Microbiology, Washington University in St. Louis School of Medicine, St. Louis, MO 63110, USA.
    Hultgren, Scott J
    Molecular Microbiology, Washington University in St. Louis School of Medicine, St. Louis, MO 63110, USA.
    Almqvist, Fredrik
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Carboxylic acid isosteres improve the activity of ring-fused 2-pyridones that inhibit pilus biogenesis in E. coli2008Ingår i: Bioorganic & Medicinal Chemistry Letters, Vol. 18, nr 12, s. 3536-3540Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Ring-fused 2-pyridones, termed pilicides, are small synthetic compounds that inhibit pilus assembly in uropathogenic Escherichia coli. Their biological activity is clearly dependent upon a carboxylic acid functionality. Here, we present the synthesis and biological evaluation of carboxylic acid isosteres, including, for example, tetrazoles, acyl sulfonamides, and hydroxamic acids of two lead 2-pyridones. Two independent biological evaluations show that acyl sulfonamides and tetrazoles significantly improve pilicide activity against uropathogenic E. coli.

  • 44.
    Åberg, Veronica
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Hedenström, Mattias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Pinkner, Jerome S.
    Hultgren, SJ.
    Almqvist, Fredrik
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    C-Terminal properties are important for ring-fused 2-pyridones that interfere with the chaperone function in uropathogenic E-coli2005Ingår i: Organic and biomolecular chemistry, ISSN 1477-0520, E-ISSN 1477-0539, Vol. 3, nr 21, s. 3886-3892Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Virulence-associated organelles, termed pili or fimbriae, are assembled via the highly conserved chaperone–usher pathway in a vast number of pathogenic bacteria. Substituted bicyclic 2-pyridones, pilicides, inhibit pilus formation, possibly by interfering with the active site residues Arg8 and Lys112 of chaperones in uropathogenic E. coli. In this article we describe the synthesis and evaluation of nine analogues of a biologically active pilicide. Derivatization was performed with respect to its C-terminal features and the affinities for the chaperone PapD were studied with 1H relaxation-edited NMR spectroscopy. It could be concluded that the carboxylic acid functionality and also its spatial location was important for binding. In all cases, binding was significantly reduced or even abolished when the carboxylic acid was replaced by other substituents. In addition, in vivoresults from a hemagglutination assay are presented where the derivatives have been evaluated for their ability to inhibit pilus formation in uropathogenic E. coli.

  • 45.
    Åberg, Veronica
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Sellstedt, Magnus
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Hedenström, Mattias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Pinkner, Jerome S
    Hultgren, Scott J
    Almqvist, Fredrik
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Design, synthesis and evaluation of peptidomimetics based on substituted bicyclic 2-pyridones-targeting virulence of uropathogenic E. coli2006Ingår i: Bioorganic & Medicinal Chemistry, ISSN 0968-0896, E-ISSN 1464-3391, Vol. 14, nr 22, s. 7563-7581Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Substituted bicyclic 2-pyridones, termed pilicides, are dipeptide mimetics that prevent pilus assembly in uropathogenic Escherichia coli. Here, we apply rational design to produce four classes of extended peptidomimetics based on two bioactive 2-pyridones. The key intermediate in the synthesis was an amino-functionalised 2-pyridone scaffold, which could be obtained via a mild and selective nitration and subsequent reduction. Procedures were then developed to further derivatize this amino-substituted core and a total of 24 extended peptidomimetics were synthesised and evaluated for chaperone affinity and in vivo antivirulence activity in P pili producing E. coli. Enhanced affinities for the target protein were observed within the generated set of compounds, while the ability to prevent pilus assembly in vivo was significantly decreased compared to the parent lead compounds. The results suggest that the limited in vivo potencies of the analogues are either uptake/distribution related or due to loss in binding specificity.

  • 46. Öhman, David
    et al.
    Demedts, Brecht
    Kumar, Manoj
    Gerber, Lorenz
    Gorzsás, András
    Swedish University of Agricultural Sciences, Umeå.
    Goeminne, Geert
    Hedenström, Mattias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Ellis, Brian
    Boerjan, Wout
    Sundberg, Björn
    MYB103 is required for FERULATE-5-HYDROXYLASE expression and syringyl lignin biosynthesis in Arabidopsis stems2013Ingår i: The Plant Journal, ISSN 0960-7412, E-ISSN 1365-313X, Vol. 73, nr 1, s. 63-76Artikel i tidskrift (Refereegranskat)
    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. 

  • 47.
    Öman, Tommy
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Tessem, Maj-Britt
    Bathen, Tone F
    Bertilsson, Helena
    Angelsen, Anders
    Hedenström, Mattias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Andreassen, Trygve
    Identification of metabolites from 2D 1H-13C HSQC NMR using peak correlation plots2014Ingår i: BMC Bioinformatics, ISSN 1471-2105, E-ISSN 1471-2105, Vol. 15, artikel-id 413Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: Identification of individual components in complex mixtures is an important and sometimes daunting task in several research areas like metabolomics and natural product studies. NMR spectroscopy is an excellent technique for analysis of mixtures of organic compounds and gives a detailed chemical fingerprint of most individual components above the detection limit. For the identification of individual metabolites in metabolomics, correlation or covariance between peaks in 1H NMR spectra has previously been successfully employed. Similar correlation of 2D 1H-13C Heteronuclear Single Quantum Correlation spectra was recently applied to investigate the structure of heparine. In this paper, we demonstrate how a similar approach can be used to identify metabolites in human biofluids (post-prostatic palpation urine).

    Results: From 50 1H-13C Heteronuclear Single Quantum Correlation spectra, 23 correlation plots resembling pure metabolites were constructed. The identities of these metabolites were confirmed by comparing the correlation plots with reported NMR data, mostly from the Human Metabolome Database.

    Conclusions: Correlation plots prepared by statistically correlating 1H-13C Heteronuclear Single Quantum Correlation spectra from human biofluids provide unambiguous identification of metabolites. The correlation plots highlight cross-peaks belonging to each individual compound, not limited by long-range magnetization transfer as conventional NMR experiments.

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