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  • 1.
    Elgland, Mathias
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Nordeman, P.
    Uppsala University, Sweden.
    Fyrner, Timmy
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Antoni, G.
    Uppsala University, Sweden.
    Nilsson, Peter
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Konradsson, Peter
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    beta-Configured clickable [F-18] FDGs as novel F-18-fluoroglycosylation tools for PET2017In: New Journal of Chemistry, ISSN 1144-0546, E-ISSN 1369-9261, Vol. 41, no 18, p. 10231-10236Article in journal (Refereed)
    Abstract [en]

    In oncology and neurology the F-18-radiolabeled glucose analogue 2-deoxy-2-[F-18]fluoro-D-glucose ([F-18]FDG) is by far the most commonly employed metabolic imaging agent for positron emission tomography (PET). Herein, we report a novel synthetic route to beta-configured mannopyranoside precursors and a chemoselective F-18-fluoroglycosylation method that employ two b-configured [F-18]FDG derivatives equipped with either a terminal azide or alkyne aglycon respectively, for use as a CuAAC clickable tool set for PET. The b-configured precursors provided the corresponding [F-18]FDGs in a radiochemical yield of 77-88%. Further, the clickability of these [F-18]FDGs was investigated by click coupling to the suitably functionalized Fmoc-protected amino acids, Fmoc-N-(propargyl)-glycine and Fmoc-3-azido-L-alanine, which provided the F-18-fluoroglycosylated amino acid conjugates in radiochemical yields of 75-83%. The F-18-fluoroglycosylated amino acids presented herein constitute a new and interesting class of metabolic PET radiotracers.

  • 2.
    Fyrner, Timmy
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Synthesis of Orthogonally Functionalized Oligosaccharides for Self-assembled Monolayers and as Multimodal Tools in Chemical Biology2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis covers different topics in the field of synthetic organic chemistry combined with the field of surface science and glycobiology.

    First, the text presents a series of orthogonally protected oligosaccharides (tri-, penta-, and heptasaccharides) of varying length and structures, which are synthesized with the aim of developing novel heterobifunctional biocompatible cross-linkers. Successful conjugation with different chemical handles is also described and used to illustrate the potential implementation of defined carbohydrate based compounds have potential use in biosensing applications. The results of incubation experiments using living cells indicate that the linker is incorporated into cell surfaces and enriched in microdomains.

    Second, synthesis of various saccharide-terminated alkane thiols immobilized on gold surfaces is reported. The protein adsorption and antifouling characteristics of these surfaces were investigated using model proteins and the common fouling organisms, Ulva linza and Balanus amphitrite.

    Further, oligo(lactose)-based thiols (di-, tetra-, and hexasaccharides) were synthesized and immobilized on gold nanoparticles to investigate how well these rigid, rod-like oligosaccharides can stabilize such nanoparticles for future use in constructing hybrid nanoparticles.

    Finally, the thesis describes synthesis of a systematic series of oligo(ethylene) glycols possessing either hydrogen- or methyl-terminated groups. Investigation of the fundamental characteristics of self-assembled monolayers, will give important insights into the design of protein repellant surfaces.

    List of papers
    1. Synthesis of tri-, penta-, and hepta-saccharides, functionalized with Orthogonally N-Protected Amino residues at the reducing and non-reducing ends
    Open this publication in new window or tab >>Synthesis of tri-, penta-, and hepta-saccharides, functionalized with Orthogonally N-Protected Amino residues at the reducing and non-reducing ends
    2012 (English)In: Tetrahedron, ISSN 0040-4020, E-ISSN 1464-5416, Vol. 68, no 33, p. 6712-6720Article in journal (Refereed) Published
    Abstract [en]

    The synthesis of four bifunctionalized orthogonally N-protected oligosaccharides derived from lactose and mannose, intended as cross-linking derivatives, is described. The amino sugar at the non-reducing end is derivatized with an N-Boc-protected glycine moiety, and further connected to either a mannose (1→6) disaccharide or (1→3) lactose units (one, two or three) resulting in tri-, penta-, or heptasaccharides. All of the synthesized oligosaccharides have an Nbenzyloxycarbonyl-aminoethyl residue at the reducing end. The fully orthogonal N-Boc/N-Cbz protection group pattern enables further conjugation/derivatization and results in a hydrophilic cross-linking molecule. It was found that the order of the final synthetic steps were crucial to avoid acyl migration. A suitable amide coupling protocol has been applied to introduce the NBoc-protected glycine moiety in alcoholic solvent. The synthesized oligosaccharides will provide a model system to investigate the influence of length, structure and flexibility. The function of the cross-linked substituents thereby provide valuable insights into the role as a spacer molecule.

    Keywords
    Glycosylation, glycosidation, oligosaccharide synthesis, spacer molecules, orthogonally protected, carbohydrates, bifunctionalized
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-76730 (URN)10.1016/j.tet.2012.05.118 (DOI)000306618400009 ()
    Available from: 2012-04-18 Created: 2012-04-18 Last updated: 2017-12-07Bibliographically approved
    2. Derivatization of a bioorthogonal protected trisaccharide linker: towards multimodal tools for chemical biology
    Open this publication in new window or tab >>Derivatization of a bioorthogonal protected trisaccharide linker: towards multimodal tools for chemical biology
    Show others...
    2012 (English)In: Bioconjugate chemistry, ISSN 1043-1802, E-ISSN 1520-4812, Vol. 23, no 6, p. 1333-1340Article in journal (Refereed) Published
    Abstract [en]

    When cross-linking biomolecules to surfaces or to other biomolecules, the use of appropriate spacer molecules is of great importance. Mimicking the naturally occurring spacer molecules will give further insight into their role and function, possibly unveil important issues regarding the importance of the specificity of carbohydrate-based anchor moieties, in e.g., glycoproteins and glycosylphosphatidylinositols. Herein, we present the synthesis of a lactoside-based trisaccharide, potentially suitable as a heterobifunctional bioorthogonal linker molecule whereon valuable chemical handles have been conjugated. An amino-derivative having thiol functionality shows promise as novel SPR-surfaces. Furthermore, the trisaccharide has been conjugated to a cholesterol moiety in combination with a fluorophore which successfully assemble on the cell surface in lipid microdomains, possibly lipid-rafts. Finally, a CuI-catalyzed azide-alkyne cycloaddition reaction (CuAAC) confirms the potential use of oligosaccharides as bioorthogonal linkers in chemical biology.

    Place, publisher, year, edition, pages
    American Chemical Society (ACS), 2012
    Keywords
    spacer molecule, oligosaccharide-based, cholesterol anchor, SPR, lipid rafts, click-chemistry
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-76735 (URN)10.1021/bc300160a (DOI)000305358700027 ()
    Available from: 2012-04-18 Created: 2012-04-18 Last updated: 2018-04-25
    3. Saccharide-Functionalized Alkanethiols for Fouling-Resistant Self-Assembled Monolayers: Synthesis, Monolayer Properties, and Antifouling Behavior
    Open this publication in new window or tab >>Saccharide-Functionalized Alkanethiols for Fouling-Resistant Self-Assembled Monolayers: Synthesis, Monolayer Properties, and Antifouling Behavior
    Show others...
    2011 (English)In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 27, no 24, p. 15034-15047Article in journal (Refereed) Published
    Abstract [en]

    We describe the synthesis of a series of mono-, di-, and trisaccharide-functionalized alkanethiols as well as the formation of fouling-resistant self-assembled monolayers (SAMs) from these. The SAls,,Is were characterized using ellipsometry, wetting measurements, and infrared reflection absorption spectroscopy (WAS). We show that the structure of the carbohydrate moiety affects the packing density and that this also alters the alkane chain organization. Upon increasing the size of the sugar moieties (from mono- to di- and trisaccharides), the structural qualities of the monolayers deteriorated with increasing disorder, and for the trisaccharide, slow reorganization dynamics in response to changes in the environmental polarity were observed. The antifouling properties of these SAMs were investigated through protein adsorption experiments from buffer solutions as well as settlement (attachment) tests using two common marine fouling species, zoospores of the green macroalga Ulva linza and cypris larvae of the barnacle Balanus amphitrite. The SAMs showed overall good resistance to fouling by both the proteins and the tested marine organisms. To improve the packing density of the SAMs with bulky headgroups, we employed mixed SAMs where the saccharide-thiols are diluted with a filler molecule having a small 2-hydroxyethyl headgroup. This method also provides a means by which the steric availability of sugar moieties can be varied, which is of interest for specific interaction studies with surface-bound sugars. The results of the surface dilution study and the low nonspecific adsorption onto the SAMs both indicate the feasibility of this approach.

    Place, publisher, year, edition, pages
    American Chemical Society, 2011
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-75120 (URN)10.1021/la202774e (DOI)000298118500040 ()
    Note

    Funding Agencies|AMBIO|NMP-CT-2005-011827|European Commission||

    Available from: 2012-02-21 Created: 2012-02-17 Last updated: 2017-05-31Bibliographically approved
    4. Synthesis of oligo(lactose)-based thiols and their self-assembly onto gold surfaces
    Open this publication in new window or tab >>Synthesis of oligo(lactose)-based thiols and their self-assembly onto gold surfaces
    Show others...
    2013 (English)In: Colloids and Surfaces B: Biointerfaces, ISSN 0927-7765, E-ISSN 1873-4367, Vol. 105, p. 187-193Article in journal (Refereed) Published
    Abstract [en]

    The ability to produce monomolecular coatings with well-defined structural and functional properties is of key importance in biosensing, drug delivery, and many recently developed applications of nanotechnology. Organic chemistry has proven to be a powerful tool to achieve this in many research areas. Herein, we present the synthesis of three oligo(lactosides) glycosylated in a (1 → 3) manner, and which are further functionalized with amide-linked short alkanethiol spacers. The oligosaccharides (di-, tetra-, and hexasaccharide) originate from the inexpensive and readily available lactose disaccharide. These thiolated derivatives were immobilized onto gold surfaces, and the thus formed self-assembled monolayers (SAMs) on planar gold were characterized by wettability, ellipsometry and infrared reflection–absorption spectroscopy. Further, the ability of these SAMs to stabilize gold nanoparticles in saline solutions was also demonstrated, indicating that the oligosaccharides may be used as stabilizing agents in gold nanoparticle-based assays.

    Place, publisher, year, edition, pages
    Elsevier, 2013
    Keywords
    Oligosaccharides, Lactose, Self-assembled monolayers, Gold nanoparticles
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-92697 (URN)10.1016/j.colsurfb.2013.01.002 (DOI)000316589500027 ()
    Note

    The previous status of this article was Manuscript.

    Available from: 2013-05-16 Created: 2013-05-16 Last updated: 2017-05-31Bibliographically approved
    5. Spectroscopic Characterization and Modeling of Methyl- and Hydrogen-Terminated Oligo (ethylene glycol) Self-Assembled Monolayers
    Open this publication in new window or tab >>Spectroscopic Characterization and Modeling of Methyl- and Hydrogen-Terminated Oligo (ethylene glycol) Self-Assembled Monolayers
    Show others...
    2012 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 116, no 22, p. 12008-12016Article in journal (Refereed) Published
    Abstract [en]

    Two series of oligo (ethylene glycol) (OEG) thiol compounds HS-(CH2CH2O)nR with R = CH3, H and n = 5, 6, 7, have been synthesized and used to form self-assembled monolayers (SAMs) on gold. The data from null ellipsometry, infrared reflection-absorption spectroscopy and ab initio calculations of this type of OH- and CH3-terminated OEG SAMs are used to examine the rarely addressed in-SAM orientation of oligo (ethylene glycols) and to provide detailed assignments of infrared bands in the fingerprint and CH-stretching regions. Based on these results, a new spectral band has been observed at 2947 cm-1 and identified by the firstprinciple calculations as localized vibrations that are specific for hydrogen-terminated OEG thiolate SAMs. This band can be used as an indicator of a high crystalline like ordering. It is further more stressed that theory agrees with the experimentally obtained CH-stretching spectra remarkably well if, and only if, the OEG helix axis within studied SAMs is tilted by about 20o with respect to the surface normal.

    Keywords
    Oligo(ethylene glycol) self-assembled monolayers, infrared reflection absorption spectroscopy, first-principle calculations
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-77052 (URN)10.1021/jp212400z (DOI)000304888700021 ()
    Available from: 2012-05-03 Created: 2012-05-03 Last updated: 2017-12-07Bibliographically approved
  • 3.
    Fyrner, Timmy
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Ederth, Thomas
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Physics. Linköping University, Faculty of Science & Engineering.
    Aili, Daniel
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Physics. Linköping University, Faculty of Science & Engineering.
    Liedberg, Bo
    Nanyang Technology University, Singapore .
    Konradsson, Peter
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering. Linköping, .
    Synthesis of oligo(lactose)-based thiols and their self-assembly onto gold surfaces2013In: Colloids and Surfaces B: Biointerfaces, ISSN 0927-7765, E-ISSN 1873-4367, Vol. 105, p. 187-193Article in journal (Refereed)
    Abstract [en]

    The ability to produce monomolecular coatings with well-defined structural and functional properties is of key importance in biosensing, drug delivery, and many recently developed applications of nanotechnology. Organic chemistry has proven to be a powerful tool to achieve this in many research areas. Herein, we present the synthesis of three oligo(lactosides) glycosylated in a (1 → 3) manner, and which are further functionalized with amide-linked short alkanethiol spacers. The oligosaccharides (di-, tetra-, and hexasaccharide) originate from the inexpensive and readily available lactose disaccharide. These thiolated derivatives were immobilized onto gold surfaces, and the thus formed self-assembled monolayers (SAMs) on planar gold were characterized by wettability, ellipsometry and infrared reflection–absorption spectroscopy. Further, the ability of these SAMs to stabilize gold nanoparticles in saline solutions was also demonstrated, indicating that the oligosaccharides may be used as stabilizing agents in gold nanoparticle-based assays.

  • 4.
    Fyrner, Timmy
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Organic Chemistry. Linköping University, The Institute of Technology.
    Konradsson, Peter
    Linköping University, Department of Physics, Chemistry and Biology, Organic Chemistry. Linköping University, The Institute of Technology.
    Modified surfaces using tailor-made oligosaccharides having orthogonal attachments2011In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 241, p. 107-CARB-Article in journal (Other academic)
    Abstract [en]

    The ability of fabricating surfaces with low non-specific protein adhesion is of great interest in material science. Studies have shown that self-assembled monolayers (SAMs) covered with carbohydrates moieties have protein resistant characteristics and even marine anti-fouling properties.[1,2]The presented results describe the synthesis of oligosaccharides originating from lactose and mannose. We have also set out to investigate if these orthogonally protected oligosaccharides can be used as spacer molecules and their performance in protein adsorption studies. Using the selected divergence enables incorporation into various surface systems e.g. gold nanoparticles, vesicles or as a conjugate between different macromolecules.

    [1] Hederos, M.; Konradsson, P.; Liedberg, B.; Langmuir, 2005, 21, 2971-2980.[2] Fyrner, T.; Konradsson, P.; et. al.; Submitted, 2010.

  • 5.
    Fyrner, Timmy
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Lee, Hung-Hsun
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Physics. Linköping University, Faculty of Science & Engineering.
    Mangone, Alberto
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Physics. Linköping University, Faculty of Science & Engineering.
    Ekblad, Tobias
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Physics. Linköping University, Faculty of Science & Engineering.
    Pettitt, Michala E
    University of Birmingham, UK.
    Callow, Maureen E
    University of Birmingham, UK.
    Callow, James A
    University of Birmingham, UK.
    Conlan, Sheelagh L
    Newcastle University, UK.
    Mutton, Robert
    Newcastle University, UK.
    Clare, Anthony S
    Newcastle Universitym, UK.
    Konradsson, Peter
    Linköping University, Department of Physics, Chemistry and Biology, Organic Chemistry. Linköping University, The Institute of Technology.
    Liedberg, Bo
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Physics. Linköping University, Faculty of Science & Engineering.
    Ederth, Thomas
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Physics. Linköping University, Faculty of Science & Engineering.
    Saccharide-Functionalized Alkanethiols for Fouling-Resistant Self-Assembled Monolayers: Synthesis, Monolayer Properties, and Antifouling Behavior2011In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 27, no 24, p. 15034-15047Article in journal (Refereed)
    Abstract [en]

    We describe the synthesis of a series of mono-, di-, and trisaccharide-functionalized alkanethiols as well as the formation of fouling-resistant self-assembled monolayers (SAMs) from these. The SAls,,Is were characterized using ellipsometry, wetting measurements, and infrared reflection absorption spectroscopy (WAS). We show that the structure of the carbohydrate moiety affects the packing density and that this also alters the alkane chain organization. Upon increasing the size of the sugar moieties (from mono- to di- and trisaccharides), the structural qualities of the monolayers deteriorated with increasing disorder, and for the trisaccharide, slow reorganization dynamics in response to changes in the environmental polarity were observed. The antifouling properties of these SAMs were investigated through protein adsorption experiments from buffer solutions as well as settlement (attachment) tests using two common marine fouling species, zoospores of the green macroalga Ulva linza and cypris larvae of the barnacle Balanus amphitrite. The SAMs showed overall good resistance to fouling by both the proteins and the tested marine organisms. To improve the packing density of the SAMs with bulky headgroups, we employed mixed SAMs where the saccharide-thiols are diluted with a filler molecule having a small 2-hydroxyethyl headgroup. This method also provides a means by which the steric availability of sugar moieties can be varied, which is of interest for specific interaction studies with surface-bound sugars. The results of the surface dilution study and the low nonspecific adsorption onto the SAMs both indicate the feasibility of this approach.

  • 6.
    Fyrner, Timmy
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Organic Chemistry. Linköping University, Faculty of Science & Engineering.
    Magnusson, Karin
    Linköping University, Department of Physics, Chemistry and Biology, Organic Chemistry. Linköping University, Faculty of Science & Engineering.
    Nilsson, Peter
    Linköping University, Department of Physics, Chemistry and Biology, Organic Chemistry. Linköping University, The Institute of Technology.
    Hammarström, Per
    Linköping University, Department of Physics, Chemistry and Biology, Biochemistry. Linköping University, The Institute of Technology.
    Aili, Daniel
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics. Linköping University, The Institute of Technology.
    Konradsson, Peter
    Linköping University, Department of Physics, Chemistry and Biology, Organic Chemistry. Linköping University, The Institute of Technology.
    Derivatization of a bioorthogonal protected trisaccharide linker: towards multimodal tools for chemical biology2012In: Bioconjugate chemistry, ISSN 1043-1802, E-ISSN 1520-4812, Vol. 23, no 6, p. 1333-1340Article in journal (Refereed)
    Abstract [en]

    When cross-linking biomolecules to surfaces or to other biomolecules, the use of appropriate spacer molecules is of great importance. Mimicking the naturally occurring spacer molecules will give further insight into their role and function, possibly unveil important issues regarding the importance of the specificity of carbohydrate-based anchor moieties, in e.g., glycoproteins and glycosylphosphatidylinositols. Herein, we present the synthesis of a lactoside-based trisaccharide, potentially suitable as a heterobifunctional bioorthogonal linker molecule whereon valuable chemical handles have been conjugated. An amino-derivative having thiol functionality shows promise as novel SPR-surfaces. Furthermore, the trisaccharide has been conjugated to a cholesterol moiety in combination with a fluorophore which successfully assemble on the cell surface in lipid microdomains, possibly lipid-rafts. Finally, a CuI-catalyzed azide-alkyne cycloaddition reaction (CuAAC) confirms the potential use of oligosaccharides as bioorthogonal linkers in chemical biology.

  • 7.
    Fyrner, Timmy
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Organic Chemistry. Linköping University, The Institute of Technology.
    Svensson, Stefan C.T.
    Linköping University, Department of Physics, Chemistry and Biology, Organic Chemistry. Linköping University, The Institute of Technology.
    Konradsson, Peter
    Linköping University, Department of Physics, Chemistry and Biology, Organic Chemistry. Linköping University, The Institute of Technology.
    Synthesis of tri-, penta-, and hepta-saccharides, functionalized with Orthogonally N-Protected Amino residues at the reducing and non-reducing ends2012In: Tetrahedron, ISSN 0040-4020, E-ISSN 1464-5416, Vol. 68, no 33, p. 6712-6720Article in journal (Refereed)
    Abstract [en]

    The synthesis of four bifunctionalized orthogonally N-protected oligosaccharides derived from lactose and mannose, intended as cross-linking derivatives, is described. The amino sugar at the non-reducing end is derivatized with an N-Boc-protected glycine moiety, and further connected to either a mannose (1→6) disaccharide or (1→3) lactose units (one, two or three) resulting in tri-, penta-, or heptasaccharides. All of the synthesized oligosaccharides have an Nbenzyloxycarbonyl-aminoethyl residue at the reducing end. The fully orthogonal N-Boc/N-Cbz protection group pattern enables further conjugation/derivatization and results in a hydrophilic cross-linking molecule. It was found that the order of the final synthetic steps were crucial to avoid acyl migration. A suitable amide coupling protocol has been applied to introduce the NBoc-protected glycine moiety in alcoholic solvent. The synthesized oligosaccharides will provide a model system to investigate the influence of length, structure and flexibility. The function of the cross-linked substituents thereby provide valuable insights into the role as a spacer molecule.

  • 8.
    Karlsson, Anna-Carin
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Zoology. Linköping University, The Institute of Technology.
    Jensen, Per
    Linköping University, Department of Physics, Chemistry and Biology, Zoology. Linköping University, The Institute of Technology.
    Elgland, Mathias
    Linköping University, Department of Physics, Chemistry and Biology, Organic Chemistry. Linköping University, The Institute of Technology.
    Laur, Katriann
    Linköping University, Department of Physics, Chemistry and Biology, Organic Chemistry. Linköping University, The Institute of Technology.
    Fyrner, Timmy
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Konradsson, Peter
    Linköping University, Department of Physics, Chemistry and Biology, Organic Chemistry. Linköping University, The Institute of Technology.
    Laska, Matthias
    Linköping University, Department of Physics, Chemistry and Biology, Zoology. Linköping University, The Institute of Technology.
    Red junglefowl have individual body odors2010In: JOURNAL OF EXPERIMENTAL BIOLOGY, ISSN 0022-0949, Vol. 213, no 10, p. 1619-1624Article in journal (Refereed)
    Abstract [en]

    Olfaction may play an important role in regulating bird behavior, and has been suggested to be involved in feather-pecking. We investigated possible differences in the body odors of red junglefowl females by using an automated olfactometer which assessed the ability of trained mice to discriminate between the odors of uropygial gland secretions (the main carrier of potential individual odors in chickens) of six feather-pecked and six non-pecked birds. All mice were clearly able to discriminate between all individual red junglefowl odors, showing that each bird has an individual body odor. We analyzed whether it was more difficult to discriminate between the odors of two feather-pecked, or two non-pecked birds, than it was to discriminate between the odors of two randomly selected birds. This was not the case, suggesting that feather-pecked birds did not share a common odor signature. Analyses using gas chromatography and mass spectrometry showed that the composition of aliphatic carboxylic acids in uropygial gland secretions differed consistently between individuals. However, chemical composition did not vary according to feather-pecking status. We conclude that red junglefowl have individual body odors which appear to be largely based on differences in the relative abundance of aliphatic carboxylic acids, but there is no evidence of systematic differences between the body odors of pecked and non-pecked birds.

  • 9.
    Malysheva, Lyuba
    et al.
    Bogolyubov Institute for Theoretical Physics, 03680, Kiev, Ukraine.
    Onipko, Alexander
    Bogolyubov Institute for Theoretical Physics, 03680, Kiev, Ukraine.
    Fyrner, Timmy
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Lee, Hung-Hsun
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Physics. Linköping University, Faculty of Science & Engineering.
    Valiokas, Ramūnas
    Department of Nanoengineering, Center for Physical Sciences and Engineering, Savanoriu 231, LT-02300 Vilnius, Lithuania.
    Konradsson, Peter
    Linköping University, Department of Physics, Chemistry and Biology, Organic Chemistry. Linköping University, The Institute of Technology.
    Liedberg, Bo
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics. Linköping University, The Institute of Technology.
    Spectroscopic Characterization and Modeling of Methyl- and Hydrogen-Terminated Oligo (ethylene glycol) Self-Assembled Monolayers2012In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 116, no 22, p. 12008-12016Article in journal (Refereed)
    Abstract [en]

    Two series of oligo (ethylene glycol) (OEG) thiol compounds HS-(CH2CH2O)nR with R = CH3, H and n = 5, 6, 7, have been synthesized and used to form self-assembled monolayers (SAMs) on gold. The data from null ellipsometry, infrared reflection-absorption spectroscopy and ab initio calculations of this type of OH- and CH3-terminated OEG SAMs are used to examine the rarely addressed in-SAM orientation of oligo (ethylene glycols) and to provide detailed assignments of infrared bands in the fingerprint and CH-stretching regions. Based on these results, a new spectral band has been observed at 2947 cm-1 and identified by the firstprinciple calculations as localized vibrations that are specific for hydrogen-terminated OEG thiolate SAMs. This band can be used as an indicator of a high crystalline like ordering. It is further more stressed that theory agrees with the experimentally obtained CH-stretching spectra remarkably well if, and only if, the OEG helix axis within studied SAMs is tilted by about 20o with respect to the surface normal.

  • 10.
    Mishra, Rajesh
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering. Jawaharlal Nehru Univ, India.
    Elgland, Mathias
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Begum, Afshan
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Fyrner, Timmy
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Science & Engineering.
    Konradsson, Peter
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Nyström, Sofie
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Hammarström, Per
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Impact of N-glycosylation site variants during human PrP aggregation and fibril nucleation2019In: Biochimica et Biophysica Acta - Proteins and Proteomics, ISSN 1570-9639, E-ISSN 1878-1454, Vol. 1867, no 10, p. 909-921Article in journal (Refereed)
    Abstract [en]

    Misfolding and aggregation of the human prion protein (PrP) cause neurodegenerative transmissible spongiform encephalopathies such as Creutzfeldt-Jakob disease. Mature native PrP is composed of 209 residues and is folded into a C-terminal globular domain (residues 125-209) comprising a small two-stranded beta-sheet and three alpha-helices. The N-terminal domain (residues 23-124) is intrinsically disordered. Expression of truncated PrP (residues 90-231) is sufficient to cause prion disease and residues 90/100-231 is comprising the amyloid-like fibril core of misfolded infectious PrP. During PrP fibril formation under native conditions in vitro, the disordered N-terminal domain slows down fibril formation likely due to a mechanism of initial aggregation forming morphologically disordered aggregates. The morphological disordered aggregate is a transient phase. Nucleation of fibrils occurs from this initial aggregate. The aggregate phase is largely circumvented by seeding with preformed PrP fibrils. In vivo PrP is N-glycosylated at positions Asn181 and Asn197. Little is known about the importance of these positions and their glycans for PrP stability, aggregation and fibril formation. We have in this study taken a step towards that goal by mutating residues 181 and 197 for cysteines to study the positional impact on these processes. We have further by organic synthetic chemistry and chemical modification generated synthetic glycosylations in these positions. Our data shows that residue 181 when mutated to a cysteine is a key residue for self -chaperoning, rendering a trap in the initial aggregate preventing conformational changes towards amyloid fibril formation. Position 197 is less involved in the aggregate trapping and is more geared towards beta-sheet structure conversion within amyloid fibrils. As expected, synthetic glycosylated 197 is less affected towards fibril formation compared to glycosylated 181. Our data are rather compatible with the parallel in-register intermolecular beta-sheet model structure of the PrP90-231 fibril and sheds light on the misfolding transitions of PrP in vitro. We hypothesize that glycosylation of position 181 is a key site for prion strain differentiation in vivo.

  • 11.
    Nugraha, Roni
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics. Linköping University, The Institute of Technology.
    Finlay, John A.
    University of Birmingham, England.
    Hill, Sophie
    University of Birmingham, England.
    Fyrner, Timmy
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology.
    Yandi, Wetra
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Physics. Linköping University, The Institute of Technology.
    Callow, Maureen E.
    University of Birmingham, England.
    Callow, James A.
    University of Birmingham, England.
    Ederth, Thomas
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Physics. Linköping University, The Institute of Technology.
    Antifouling properties of oligo(lactose)-based self-assembled monolayers2015In: Biofouling (Print), ISSN 0892-7014, E-ISSN 1029-2454, Vol. 31, no 1, p. 123-134Article in journal (Refereed)
    Abstract [en]

    The antifouling (AF) properties of oligo(lactose)-based self-assembled monolayers (SAMs), using four different proteins, zoospores of the green alga Ulva linza and cells of the diatom Navicula incerta, were investigated. The SAM-forming alkylthiols, which contained 1, 2 or 3 lactose units, showed significant variation in AF properties, with no differences in wettability. Non-specific adsorption of albumin and pepsin was low on all surfaces. Adsorption of lysozyme and fibrinogen decreased with increasing number of lactose units in the SAM, in agreement with the generally observed phenomenon that thicker hydrated layers provide higher barriers to protein adsorption. Settlement of spores of U. linza followed an opposite trend, being greater on the bulkier, more hydrated SAMs. These SAMs are more ordered for the larger saccharide units, and it is therefore hypothesized that the degree of order, and differences in crystallinity or stiffness between the surfaces, is an important parameter regulating spore settlement on these surfaces.

  • 12.
    Villamil Giraldo, Ana Maria
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    Fyrner, Timmy
    Linköping University, Faculty of Science & Engineering. Linköping University, Department of Physics, Chemistry and Biology, Chemistry.
    Wennmalm, Stefan
    Royal Institute Technology, Sweden.
    Parikh, Atul N.
    University of Calif Davis, CA 95616 USA; University of Calif Davis, CA 95616 USA.
    Öllinger, Karin
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Clinical Pathology and Clinical Genetics.
    Ederth, Thomas
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Physics. Linköping University, Faculty of Science & Engineering.
    Spontaneous Vesiculation and pH-Induced Disassembly of a Lysosomotropic Detergent: Impacts on Lysosomotropism and Lysosomal Delivery2016In: LANGMUIR, ISSN 0743-7463, Vol. 32, no 50, p. 13566-13575Article in journal (Refereed)
    Abstract [en]

    Lysosomotropic detergents (LDs) selectively rupture lysosomal membranes through mechanisms that have yet to be characterized. A consensus view, currently, holds that LDs, which are weakly basic, diffuse across cellular membranes as monomers in an uncharged state, and via protonation in the acidic lysosomal compartment, they become trapped, accumulate, and subsequently solubilize the membrane and induce lysosomal membrane permeabilization. Here we demonstrate that the lysosomotropic detergent O-methyl-serine dodecylamide hydrochloride (MSDH) spontaneously assembles into vesicles at, and above, cytosolic pH, and that the vesicles disassemble as the pH reaches 6.4 or lower. The aggregation commences at concentrations below the range of those used in cell studies. Assembly and disassembly of the vesicles was studied via dynamic light scattering, zeta potential measurements, cryo-TEM, and fluorescence correlation spectroscopy and was found to be reversible via control of the pH. Aggregation of MSDH into closed vesicles under cytosolic conditions is at variance with the commonly held view of LD behavior, and we propose that endocytotic pathways should be considered as possible routes of LD entry into lysosomes. We further demonstrate that MSDH vesicles can be loaded with fluorophores via a solution transition from low to high pH, for subsequent release when the pH is lowered again. The ability to encapsulate molecular cargo into MSDH vesicles together with its ability to disaggregate at low pH and to permeabilize the lysosomal membrane presents an intriguing possibility to use MSDH as a delivery system.

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