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  • 201.
    Isaksson, Dan
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Sjödin, Kristina
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Högberg, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Enantiomerically enriched cryptone by lipase catalysed kinetic resolution2006In: Tetrahedron: asymmetry, ISSN 0957-4166, E-ISSN 1362-511X, Vol. 17, no 2, p. 275-280Article in journal (Refereed)
    Abstract [en]

    Thiophenol was added to racemic cryptone (4-isopropyl-2-cyclohexene-1-one) and the resulting 1,4-addition products, cis- and trans-4-isopropyl-3-(phenylsulfanyl)cyclohexanone) were separated and the latter reduced to rac-1,3-cis-1,4-trans-4-isopropyl-3-(phenylsulfanyl)cyclo¬he¬xanol which was subjected to lipase catalysed resolution by acylation catalysed by CAL-B (Candida antarctica lipase B). The remaining alcohol was separated from the produced acetate, which was hydrolysed to the alcohol. The enantiomeric alcohols so obtained were oxidised. The initial products, probably sulfoxidoketones spontaneously decomposed to furnish enantiomerically enriched (R)- and (S)-cryptone with up to 76% and 98% ee, respectively.

  • 202. Ivarsson, P
    et al.
    Tittiger, C
    Blomquist, C
    Borgeson, C
    Seybold, S
    Blomquist, G
    Högberg, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Pheromone precursor synthesis is localized in the metathorax of Ips paraconfusus Lanier (Coleoptera : Scolytidae)1998In: Naturwissenschaften, ISSN 0028-1042, Vol. 85, no 10, p. 507-511Article in journal (Refereed)
  • 203.
    Jiang, Liying
    et al.
    Stockholm Univ, Dept Analyt Chem, SE-10691 Stockholm, Sweden.
    Dziedzic, Pawel
    Stockholm Univ, Dept Organ Chem, SE-10691 Stockholm, Sweden.
    Spacil, Zdenek
    Stockholm Univ, Dept Analyt Chem, SE-10691 Stockholm, Sweden.
    Zhao, Gui-Ling
    Stockholm Univ, Dept Organ Chem, SE-10691 Stockholm, Sweden.
    Nilsson, Lennart
    Karolinska Inst, SE-17177 Stockholm, Sweden.
    Ilag, Leopold L.
    Stockholm Univ, Dept Analyt Chem, SE-10691 Stockholm, Sweden.
    Cordova, Armando
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences. Stockholm Univ, Dept Organ Chem, SE-10691 Stockholm, Sweden.
    Abiotic synthesis of amino acids and self-crystallization under prebiotic conditions2014In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 4, p. Art. no. 6769-Article in journal (Refereed)
    Abstract [en]

    Building on previous research on the origin and homochirality of life, this study focuses on analyses profiling important building blocks of life: the natural amino acids. The spark discharge variation of the iconic Miller experiment was performed with a reducing gas mixture of ammonia, methane, water and hydrogen. Amino acid analysis using liquid chromatography coupled with tandem mass spectrometry after pre-column derivatizaiton revealed the generation of several amino acids including those essential for life. Re-crystallization of the synthetic products and enantiomeric ratio analysis were subsequently performed. Results from liquid chromatography coupled with either fluorescent detector or tandem mass spectrometry after pre-column derivatization with chiral reagent revealed spontaneous and effective asymmetric resolution of serine and alanine. This work describes a useful analytical platform for investigation of hypotheses regarding the origin and homochirality of amino acids under prebiotic conditions. The formation of numerous amino acids in the electric discharge experiment and the occurrence of high enantiomeric ratios of amino acids in re-crystallization experiment give valuable implications for future studies in unraveling fundamental questions regarding origins and evolution of life.

  • 204.
    Jiang, Yan
    et al.
    Stockholm University, Stockholm.
    Deiana, Luca
    Stockholm University, Stockholm.
    Alimohammadzadeh, Rana
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences. Stockholm University, Stockholm.
    Liu, Leifeng
    Stockholm University, Stockholm.
    Sun, Junliang
    Stockholm University, Stockholm.
    Córdova, Armando
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences. Stockholm University, Stockholm.
    Highly Diastereo- and Enantioselective Cascade Synthesis of Bicyclic Lactams in One-Pot2018In: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, Vol. 2018, no 9, p. 1158-1164Article in journal (Refereed)
    Abstract [en]

    A versatile and highly stereoselective synthetic route to functionalized bi- and tricyclic lactams (up to > 20:1 dr and 99 % ee) in one pot from simple starting materials (allylic alcohols, enals, diamines and amino alcohols) using cascade transformations promoted by chiral amine/Brønsted or metal/chiral amine/Brønsted relay catalysis is disclosed. Here molecular oxygen is employed as the terminal oxidant for the latter relay catalysis approach. 

  • 205. Johansson, Björn
    et al.
    Anderbrant, Olle
    Simandl, Jiri
    Avtzis, Nikolaos
    Salvadori, Christina
    Hedenström, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Edlund, Helen
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Högberg, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Release Rates for Pine Sawfly Pheromones from Two Types of Dispensers and Phenology of Neodiprion sertifer2001In: Journal of Chemical Ecology, ISSN 0098-0331, E-ISSN 1573-1561, Vol. 27, no 4, p. 733-745Article in journal (Refereed)
    Abstract [en]

    Comparisons of release rates, duration in the field, and catch efficiency of polyethylene and cotton roll dispensers for the sex pheromones of sawflies (Hymenoptera: Diprionidae) were conducted. The release rates of the Neodiprion sertifer (Geoffr.) and Diprion pini (L.) sex pheromones, the acetates of pentadecanol and (2S,3S,7S)-3,7-dimethyl (2S,3R,7R)-3,7-dimethyl-2-tridecanol from polyethylene dispensers were measured at different temperatures in the laboratory. The release rates for the substances depended on both the temperature and initial load in the vials. The catch from cotton rolls baited with 100 μg of the acetate or propionate of 3,7-dimethyl-2-pentadecanol was compared to the catch from regularly renewed cotton rolls baited with 10 μg of the same acetate. The catch was higher for the 100-μg cotton rolls for, at most, 45 days, and there was no significant difference in catch between the acetate and the propionate. The catch in traps baited with polyethylene or cotton roll dispensers loaded with the acetate of 3,7-dimethyl-2-pentadecanol was compared and showed that cotton roll traps mirrored the decreasing release of the substance rather than the actual flight activity. The length of the flight period of N. sertifer in Sweden, the Czech Republic, Italy, and Greece did not exceed 100 days in any of the countries. By adjusting the initial pheromone load of the polyethylene vials to the expected temperatures, it should be possible to get a constant and sufficiently high release rate during the entire flight period.

  • 206. Johansson, E
    et al.
    Lingström, R
    Norgren, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Wågberg, L
    Evaluation of Adhesion between Polyelectrolyte Multilayers using AFM. : Poster - Veeco Scandinavian User Meeting2007Conference paper (Other scientific)
  • 207. Johansson, Erik
    et al.
    Lundström, Lisa
    Norgren, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Wågberg, Lars
    Adsorption Behavior and Adhesive Properties of Biopolyelectrolyte Multilayers Formed from Cationic and Anionic Starch.2009In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 10, no 7, p. 1768-1776Article in journal (Refereed)
    Abstract [en]

    Cationic starch (D.S. 0.065) and anionic starch (D.S. 0.037) were used to form biopolyelectrolyte multilayers. The influence of the solution concentration of NaCl on the adsorption of starch onto silicon oxide substrates and on the formation of multilayers was investigated using stagnation point adsorption reflectometry (SPAR) and quartz crystal microbalance with dissipation (QCM-D). The wet adhesive properties of the starch multilayers were examined by measuring pull-off forces with the AFM colloidal probe technique. It was shown that polyelectrolyte multilayers (PEM) can be successfully constructed from cationic starch and anionic starch at electrolyte concentrations of 1 mM NaCl and 10 mM NaCl. The water content of the PEMs was approximately 80% at both electrolyte concentrations. However, the thickness of the PEMs formed at 10 mM NaCl was approximately twice the thickness formed at I mM NaCl. The viscoelastic properties of the starch PEMs, modeled as Voigt elements, were dependent on the polyelectrolyte that was adsorbed in the outermost layer. The PEMs appeared to be more rigid when capped by anionic starch than when capped by cationic starch. The wet adhesive pull-off forces increased with layer number and were also dependent oil the polyelectrolyte adsorbed in the outermost layer. Thus, starch PEM treatment has a large potential for increasing the adhesive interaction between solid substrates to levels higher than can be reached by a single layer of cationic starch.

  • 208. Jones, D L
    et al.
    Dennis, P G
    Owen, A G
    van Hees, P A W
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Organic acid behavior in soils - misconceptions and knowledge gaps2003In: Plant and Soil, ISSN 0032-079X, E-ISSN 1573-5036, Vol. 248, no 1-2, p. 31-41Article in journal (Refereed)
    Abstract [en]

    Organic acids have been hypothesized to perform many functions in soil including root nutrient acquisition, mineral weathering, microbial chemotaxis and metal detoxification. However, their role in most of these processes remains unproven due to a lack of fundamental understanding about the reactions of organic acids in soil. This review highlights some of the knowledge gaps and misconceptions associated with the behavior of organic acids in soil with particular reference to low-molecular-weight organic acids (e.g., citrate, oxalate, malate) and plant nutrient acquisition. One major concern is that current methods for quantifying organic acids in soil may vastly underestimate soil solution concentrations and do not reveal the large spatial heterogeneity that may exist in their concentration (e.g., around roots or microbes). Another concern relates to the interaction of organic acids with the soil's solid phase and the lack of understanding about the relative importance of processes such as adsorption versus precipitation, and sorption versus desorption. Another major knowledge gap concerns the utilization of organic acids by the soil microbial community and the forms of organic acids that they are capable of degrading (e.g., metal-complexed organic acids, adsorbed organic acids etc). Without this knowledge it will be impossible to obtain accurate mathematical models of organic acid dynamics in soil and to understand their role and importance in ecosystem processes. Fundamental research on organic acids and their interaction with soil still needs to be done to fully elucidate their role in soil processes.

  • 209.
    Jonsson, Anders
    et al.
    Högskolan i Östersund.
    Berg, S.
    Determination of 1,2-dibromoethane, 1,2-dichloroethane and benzene in ambient air using porous polymer traps and gas chromatographic-mass spectrometric analysis with selected ion monitoring1980In: Journal of Chromatography A, ISSN 0021-9673, Vol. 190, p. 97-Article in journal (Refereed)
  • 210.
    Jonsson, Anders
    et al.
    Högskolan i Östersund.
    Berg, S.
    Bertilsson, B.M.
    Methylnitrite in the exhaust from a methanol-gasoline fueled automobile1979In: Chemosphere, ISSN 0045-6535, Vol. 8, p. 835-841Article in journal (Refereed)
  • 211.
    Jonsson, Anders
    et al.
    Högskolan i Östersund.
    Berg, Sven
    Determination of low-molecular-weight oxygenated hydrocarbons in ambient air by cryogradient sampling and two-dimensional gas chromatography1983In: Journal of Chromatography A, ISSN 0021-9673, Vol. 279, p. 307-322Article in journal (Refereed)
  • 212.
    Jonsson, Anders
    et al.
    Högskolan i Östersund.
    Bertilsson, B-M
    Organic nitrites in the exhaust emissions from alcohol fueled vehicles1982In: Proceedings of the Fifth International Alcohol Fuel Technology Symposium: Vol. 3, 1982, p. 179-186Conference paper (Other academic)
  • 213.
    Jonsson, Anders
    et al.
    Högskolan i Östersund.
    Bertilsson, Britt-Marie
    Formation of Methyl nitrite in engines fueled with gasoline/methanol and methanol/diesel1982In: Environmental science and technology, ISSN 0013-936X, Vol. 16, no 2, p. 106-110Article in journal (Refereed)
  • 214.
    Jonsson, Anders
    et al.
    Högskolan i Östersund.
    Persson, K.A.
    Grigoriadis, V.
    Measurements of some low molecular-weight oxygenated, aromatic, and chlorinated hydrocarbons in ambient air and in vehicle emissions1984In: Environment International, ISSN 0160-4120, Vol. 11, no 2-4, p. 383-392Article in journal (Refereed)
  • 215. Jonsson, Anders
    et al.
    Törnqvist, Margareta
    Rannug, Agneta
    Ehrenberg, Lars
    Mutagenicity of methyl nitrite in Salmonella typhimurium1983In: Mutation Research - Genetic Toxicology and Environmental Mutagenesis, ISSN 0165-1218, Vol. 117, no 1-2, p. 47-54Article in journal (Refereed)
  • 216.
    Karlsson, Staffan
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Andersson, Fredrik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Breistein, Palle
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Hedenström, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Synthesis of butenolides recently isolated from marine microorganisms2007In: Tetrahedron Letters, ISSN 0040-4039, Vol. 48, no 44, p. 7878-7881Article in journal (Refereed)
  • 217.
    Karlsson, Staffan
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Han, F
    Högberg, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Caldirola, P
    trans-3,4-Disubtituted Pyrrolidines by 1,3-Dipolar Cycloaddition: Enantioselective Approaches and their Limitations1999In: Tetrahedron: Asymmetry, ISSN 0957-4166, Vol. 10, no 13, p. 2605-2616Article in journal (Refereed)
  • 218.
    Karlsson, Staffan
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Hedenström, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Sex Pheromone of the Pine Sawfly Macrodiprion nemoralis: Stereoselective Synthesis of the Sixteen Stereoisomers of 3,7,9-Trimethyl-2-tridecyl Acetate1999In: Acta Chemica Scandinavica, ISSN 0904-213X, Vol. 53, no 8, p. 620-630Article in journal (Refereed)
  • 219.
    Karlsson, Staffan
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Högberg, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Asymmetric 1,3-dipolar cycloadditions for the construction of enantiomerically pure heterocycles. A review2001In: Organic preparations and procedures international, ISSN 0030-4948, E-ISSN 1945-5453, Vol. 33, no 2-3, p. 105-172Article, review/survey (Refereed)
  • 220.
    Karlsson, Staffan
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Högberg, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Catalytic enantioselective 1,3-dipolar cycloaddition of nitrones to cyclopent-1-enecarbaldehyde2002In: Tetrahedron: Asymmetry, ISSN 0957-4166, Vol. 13, no 9, p. 923-926Article in journal (Refereed)
  • 221.
    Karlsson, Staffan
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Högberg, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Diastereoselective addition of chiral azomethine ylides to cinnamoyl moieties, attached to chiral auxiliaries2001In: Tetrahedron: Asymmetry, ISSN 0957-4166, Vol. 12, no 14, p. 1975-1976Article in journal (Refereed)
    Abstract [en]

    Doubly diastereoselective 1,3-dipolar cycloadditions of chiral azomethine ylides to cinnamoyl moieties, attached to chiral auxiliaries, were investigated. The resulting trans-3,4-disubstituted pyrrolidines were obtained in diastereomeric ratios of up to 78:22. The influence on this ratio by the constitution of the chiral ylide was found to be rather small.

  • 222.
    Karlsson, Staffan
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Högberg, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Diastereoselective addition of chiral azomethine ylides to cyclic alpha,beta-unsaturated N-enoylbornanesultams2002In: Journal of the Chemical Society. Perkin Transactions 1, ISSN 1472-7781, Vol. 2002, no 8, p. 1076-1081Article in journal (Refereed)
    Abstract [en]

    Doubly diastereoselective 1,3-dipolar cycloaddition reactions of chiral non-racemic azomethine ylides to cyclic five-and six-membered α,β-unsaturated N-enoylbornanesultams were carried out. When suitable solvents were used, the fused bicyclic adducts formed were obtained in good diastereoselectivity. Moreover, a change of the absolute configuration of the starting ylide precursor reversed the diastereoselectivity of some such reactions. Cleavage of the chiral auxiliary of the cycloadducts furnished amino alcohols and a β-amino ester. The latter was transformed into a known precursor of an antibacterial compound.

  • 223.
    Karlsson, Staffan
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Högberg, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Enantiomerically pure trans-3,4-disubstituted tetrahydrothiophenes from diastereoselective thiocarbonyl ylide addition to chiral alpha,beta-unsaturated amides1999In: Organic Letters, ISSN 1523-7060, Vol. 1, no 10, p. 1667-1669Article in journal (Refereed)
  • 224.
    Karlsson, Staffan
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Högberg, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Organocatalysts Promote Enantioselective 1,3-Dipolar Cycloadditions of Nitrones with 1-Cycloalkene-1-carboxaldehydes2003In: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, Vol. 2003, no 15, p. 2782-2791Article in journal (Refereed)
    Abstract [en]

    In the presence of enantiopure organocatalysts, 1-cycloalkene-1-carboxaldehydes and various nitrones furnished fused isoxazolidines. Thus, some chiral pyrrolidinium salts catalyzed the formation of such cycloadducts in high diastereo- and enantioselectivity (up to 92% ee). The predominant diastereomer, the exo one, was mostly obtained in excellent diastereoselectivity (> 99:1 dr). Furthermore, after recrystallization of one of the cycloadducts, this was obtained enantiomerically pure (> 99% ee). The absolute configuration of one of the cycloadducts was determined. 

  • 225.
    Karlsson, Staffan
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Högberg, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Pheromones of Pine Sawflies: Synthesis of a Pure (2S,3R)-3-Methylalkan-2-ol Stereoisomer via an Asymmetric 1,3-Dipolar Cycloaddition; Preparation of a Pheromone Component of Macrodiprion nemoralis2000In: Synthesis, ISSN 0039-7881, Vol. 2000, no 13, p. 1863-1867Article in journal (Refereed)
    Abstract [en]

    This paper presents a new approach to the preparation of enantiomerically pure (2S,3R)-3-methylalkan-2-ols, the esters of which are sex pheromones of several pine sawflies. Thus, an asymmetric 1,3-dipolar cycloaddition between a sulfur containing 1,3-dipole and a dipolarophile attached to (1R)-camphorsultam containing a vinyl ether functionality furnished a 90:10 diastereomeric mixture of trans-3,4-disubstituted tetrahydrothiophene amides. The major one was converted to an enantiomerically pure tetrahydrothienylmethyl bromide, which was coupled with a monoalkylated dithiane unit. After Raney nickel reduction (2S,3R,7R,9S)-3,7,9-trimethyltridecan-2-ol was obtained, the acetate of which is the attractant sex pheromone component of Macrodiprion nemoralis. Because this new approach is quite efficient it can be valuable for the synthesis of similar compounds.

  • 226.
    Karlsson, Staffan
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Högberg, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Synthesis of enantiomerically pure 4-substituted pyrrolidin-3-ols via asymmetric 1,3-dipolar cycloaddition2001In: Tetrahedron: Asymmetry, ISSN 0957-4166, Vol. 12, no 14, p. 1977-1982Article in journal (Refereed)
    Abstract [en]

    Asymmetric 1,3-dipolar cycloadditions of chiral azomethine ylides to 3-benzyloxy-substituted alkenoylcamphorsultams are described. trans-3,4-Disubstituted pyrrolidines containing a protected hydroxyl group at C(4) of the pyrrolidine ring are obtained in high diastereomeric ratios. Such compounds can serve as chiral building blocks for the syntheses of enantiopure bioactive pyrrolidines. This is exemplified by a short synthetic route to a known glycosidase inhibitor, (3R,4R)-4-(hydroxymethyl)pyrrolidin-3-ol and its enantiomer.

  • 227.
    Kohls, Hannes
    et al.
    Ernst Moritz Arndt Univ Greifswald, Inst Biochem, D-17487 Greifswald, Germany.
    Anderson, Mattias
    AlbaNova Univ Ctr, Sch Biotechnol, Div Ind Biotechnol, KTH Royal Inst Technol, SE-10691 Stockholm, Sweden.
    Dickerhoff, Jonathan
    Ernst Moritz Arndt Univ Greifswald, Inst Biochem, D-17487 Greifswald, Germany.
    Weisz, Klaus
    Ernst Moritz Arndt Univ Greifswald, Inst Biochem, D-17487 Greifswald, Germany.
    Cordova, Armando
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Berglund, Per
    AlbaNova Univ Ctr, Sch Biotechnol, Div Ind Biotechnol, KTH Royal Inst Technol, SE-10691 Stockholm, Sweden.
    Brundiek, Henrike
    Enzymicals AG, D-17489 Greifswald, Germany.
    Bornscheuer, Uwe T.
    Ernst Moritz Arndt Univ Greifswald, Inst Biochem, D-17487 Greifswald, Germany.
    Hoehne, Matthias
    Ernst Moritz Arndt Univ Greifswald, Inst Biochem, D-17487 Greifswald, Germany.
    Selective Access to All Four Diastereomers of a 1,3-Amino Alcohol by Combination of a Keto Reductase- and an Amine Transaminase-Catalysed Reaction2015In: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 357, no 8, p. 1808-1814Article in journal (Refereed)
    Abstract [en]

    The biocatalytic synthesis of chiral amines has become a valuable addition to the chemists' tool-box. However, the efficient asymmetric synthesis of functionalised amines bearing more than one stereocentre, such as 1,3-amino alcohols, remains challenging. By employing a keto reductase (KRED) and two enantiocomplementary amine transaminases (ATA), we developed a biocatalytic route towards all four diastereomers of 4-amino-1-phenylpentane-2-ol as a representative molecule bearing the 1,3-amino alcohol functionality. Starting from a racemic hydroxy ketone, a kinetic resolution using an (S)-selective KRED provided optically active hydroxy ketone (86% ee) and the corresponding diketone. Further transamination of the hydroxy ketone was performed by either an (R)- or an (S)-selective ATA, yielding the (2R,4R)- and (2R,4S)-1,3-amino alcohol diastereomers. The remaining two diastereomers were accessible in two subsequent asymmetric steps: the diketone was reduced regio- and enantioselectively by the same KRED, which yielded the (S)-configured hydroxy ketone. Eventually, the subsequent transamination of the crude product with (R)- and (S)-selective ATAs yielded the remaining (2S,4R)and (2S,4S)-diastereomers, respectively.

  • 228. Koolen, J. H.
    et al.
    Moulton, Vincent
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Gutman, I.
    Improving the McClelland inequality for total pi-electron energy2000In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 320, no 3-4, p. 213-216Article in journal (Refereed)
    Abstract [en]

    The McClelland inequality, E less than or equal to root 2mn, estimates the total pi-electron energy (E) of a conjugated hydrocarbon by means of the number of carbon atoms (n) and the number of carbon-carbon bonds (m). We now show that in the general case 2m/n + root(n - 1)(2m - 4m(2)/n(2)) is a better (n,m)-type upper bound for E. An even better estimate, 4m/n + root(n - 2)(2m - 8m(2)/n(2)), holds for alternant hydrocarbons. (C) 2000 Elsevier Science B.V. All rights reserved.

  • 229. Koolen, J. H.
    et al.
    Moulton, Vincent
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Gutman, I.
    Vidovic, D.
    More hyperenergetic molecular graphs2000In: Journal of the Serbian Chemical Society, ISSN 0352-5139, E-ISSN 1820-7421, Vol. 65, no 8, p. 571-575Article in journal (Refereed)
    Abstract [en]

    If G is a molecular graph and lambda(1), lambda(2),... lambda(n) are its eigenvalues, then the energy of G is equal to E(G) = \lambda(1)\+ \lambda(2)\+... + \lambda(n)\. This energy cannot exceed the value n root(n - 1) approximate to n(3/2). The graph G is said to be hyperenergetic if E(G) > 2n - 2. We describe the construction of hyperenergetic graphs G for which E(G) approximate to 1/2 n(3/2).

  • 230.
    Koptioug, Andrei
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    New Transmission Line Resonators for ESE1998In: EPR Newsletter, Vol. 9, no 3, p. 20-22Article in journal (Other academic)
  • 231.
    Koptioug, Andrei
    et al.
    Department of Bio-Medical Physics and Bio-Engineering, University of Aberdeen, Foresterhill, Aberdeen AB9 2ZD, United Kingdom..
    Reijerse, Edward
    Klaassen, A. K.
    New Transmission-Line Resonator for Pulsed EPR1997In: Journal of magnetic resonance, ISSN 1090-7807, E-ISSN 1096-0856, no 125, p. 369-371Article in journal (Refereed)
  • 232.
    Koptyug, Andrey
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Optical Detection of the Radical-Ion Pair Spectra in Weak Magnetic Fields1987In: Doklady Akademii Nauk, ISSN 0869-5652, Vol. 297, no 6, p. 1414-1418Article in journal (Refereed)
  • 233. Koptyug, Andrey
    Weak Field ESR Spectrometer1988In: Transactions of Siberian Branch of the USSR Academy of Sciences, Vol. 1, p. 121-124Article in journal (Refereed)
  • 234.
    Koptyug, Andrey
    et al.
    Inst. of Chem. Kinetics & Combustion, Acad. of Sci., Novosibirsk, Russia.
    Grishin, Yurij
    S-band magnetron-based accessory for optical detection of ESR spectra of radiation-induced radical-ion pairs1994In: Measurement science and technology, ISSN 0957-0233, E-ISSN 1361-6501, Vol. 5, no 4, p. 363-370Article in journal (Refereed)
    Abstract [en]

    In the development of the technique of reaction yield detected magnetic resonance (RYDMR), a novel simple accessory for optical detection of ESR (OD ESR), based on the S-band continuous wave magnetron generator is presented. Basic technical requirements for the RYDMR accessories are discussed. The successful use of an S-band magnetron as a microwave source for RYDMR experiments is reported for the first time. Along with the use of a simple loop-gap resonator it permits the studies of both polar and non-polar samples with good sensitivity and field resolution. With the help of this accessory, OD ESR spectra of some new acceptors, acridin and fluorescein, were detected and some new solvents, poly(ethylene glycol) and paraffin-based high-voltage insulator oil, were successfully utilized.

  • 235.
    Koptyug, Andrey
    et al.
    Institute of Chemical Kinetics and Combustion, Siberian Branch of the USSR Academy of Sciences, Institutskaya str. 3, Novosibirsk, 630090, USSR.
    Saik, Vladimir
    Anisimov, Oleg
    Molin, Yurij
    Spin-locking in concentration-narrowed OD ESR spectra1989In: Chemical Physics, ISSN 0301-0104, E-ISSN 1873-4421, Vol. 138, no 1, p. 173-178Article in journal (Refereed)
    Abstract [en]

    The effect of spin- locking under the action of a resonance rf field of large amplitude has been observed in the optically detected ESR spectra (OD ESR) of radical-ion pairs both in strong and weak magnetic fields. "Hampering" of singlet-tgriplet transitions occurs for concentrations of aromatic acceptors in non polar solutions at room temperature from 10e-4 to 1 M. It is proposed that in spite of strong concentration narrowing OD ESR signals are inhomogeneously broadened. This can be due to neutral molecule- radical-anion aggregate formation.

  • 236.
    Larsson, Michael
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Andersson, Jimmy
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Liu, Rong
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Högberg, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Enantiopure building blocks for the synthesis of 3-methyl-2-alkanols: Diastereoselective methylmetal addition to a chiral 2-methylaldehyde followed by lipase catalysed esterification2004In: Tetrahedron: asymmetry, ISSN 0957-4166, E-ISSN 1362-511X, Vol. 15, no 18, p. 2907-2915Article in journal (Refereed)
    Abstract [en]

    The racemic synthetic building block (2R*,3R*)-3-methyl-4-(phenylsulfanyl)butan-2-ol (2R*,3R*)-2 was obtained in a high diastereomeric ratio [95:5, (2R*,3R*)/(2R*,3S*)-ratio] by Lewis acid catalysed dimethylzinc addition to racemic 2-methyl-3-(phenylsulfanyl)propanal (rac-1). Two consecutive acylations with vinyl acetate catalysed by Chirazyme L-2 (immobilised Candida antarctica lipase 13, CAL-B) led to preferential esterification of three of the four stereoisomers leaving (2S,3S)-3-methyl-4-(phenylsulfanyl)butan-2-ol (2S,3S)-2 of 98:2 dr and 98% ee. The stereoisomerically impure acetate of (2R,3R)-3-methyl-4-(phenyisulfanyl)butan-2-ol (2R,3R)-2, obtained in the first CAL-B-catalysed acylation step, was hydrolysed and reesterified using CAL-A (immobilised Novozyme SP 525) as the catalyst, which left (2R,3R)-3-methyl-4-(phenylsulfanyl)butan-2-ol (2R,3R)-2 of 98:2 dr and 99% ee as the remaining substrate. The individual enantiomers of 2-methyl-3-(phenylsulfanyl)propanal 1 were prepared from readily available (S)- and (R)-3-hydroxy-2-methylpropanoic acid methyl ester and reacted with dimethylzinc to give both enantiomers of (2R*,3R*)-3-methyl-4-(phenylsulfanyl)butan-2-ol (2R, 3R)- or (2S,3S)-2 of both high dr and ee. These products were purified by lipase catalysed acylation to give the enantiomerically and diastereomerically highly pure enantiomers (>99.5:0.5 dr, >99.9% ee). Pure (2S,3S)-3-methyl-4-(phenylsulfanyl)butan-2-ol (2S,3S)-2 was transformed into a potential pheromone precursor isolated from some pine sawflies of the genus Gilpinia, (2S,3R)-3-methylpentadecan-2-ol in 54% yield over eight steps.

  • 237.
    Larsson, Michael
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Galandrin, Elodie
    Högberg, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Diastereoselective Addition of Organozinc Reagents to 2-alkyl-3-(arylsulfanyl)propanals2004In: Tetrahedron, ISSN 0040-4020, E-ISSN 1464-5416, Vol. 60, no 47, p. 10659-10669Article in journal (Refereed)
    Abstract [en]

    The preparation of compounds incorporating the 3-hydroxy-2-methyl-1-alkyl moiety of high diastereomeric purity is described. Such compounds can serve as potential building blocks for the preparation of several kinds of natural products. Diastereoselective synthesis of two potential pine sawfly pheromone components, one the pure racemic threo-isomer of 3-methylpentadecan-2-ol and the other the racemic erythro-isomer of 3-methyltridecan-2-ol are described. The diastereoselective addition of R2Zn (R = Me, Et and n-Bu) to several 2-alkyl-3-(arylsulfanyl)propanals in the presence of a Lewis acid and CH2Cl2 as solvent was studied. An excellent diastereomeric ratio (95/5 anti-Cram/Cram) was obtained with 2-[(phenylsulfanyl)methyl]pentanal, 2-[(phenylsulfanyl)methyl]decanal and 2-[(phenylsulfanyl)methyl]dodecanal and Me2Zn in the presence of TiCl4. (C) 2004 Elsevier Ltd. All rights reserved.

  • 238.
    Larsson, Michael
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Högberg, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Diastereoselective Addition of Methylmetallic Reagents to 2-Methylaldehydes2001In: Tetrahedron, ISSN 0040-4020, Vol. 57, no 35, p. 7541-7548Article in journal (Refereed)
    Abstract [en]

    The preparation of compounds incorporating the 3-hydroxy-2-methyl-1-butyl moiety of high diastereomeric purity is described. These compounds can serve as potential building blocks for the preparation of several kinds of natural products. The diastereoselective addition of a number of methylmetal derivatives to three 3-substituted 2-methylaldehydes in various solvents was studied. An excellent diastereomeric ratio (95:5 anti-Cram/Cram) was obtained with 2-methyl-3-(phenylsulfanyl)propanal (5) and Me2Zn in the presence of TiCl4.

  • 239.
    Larsson, Michael
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Högberg, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Diasteroselective Addition to Chiral Racemic Aldehydes, via Methylmetallic Reagents.: Poster och Abstrakt, ESOC 11, Göteborgs Universitet, Göteborg1999Conference paper (Other academic)
  • 240.
    Larsson, Michael
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Högberg, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Totalsyntes av två attrahentkomponenter hos Microdiprion pallipes, via en anti-Cramselektiv addition av dimetylzink till en 2-metylaldehyd: Organikerdagarna 2004 i Linköping2004Conference paper (Other academic)
  • 241.
    Larsson, Michael
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Nguyen, Ba-Vu
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Högberg, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Hedenström, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Syntheses of the Sixteen Stereoisomers of 3,7,11-Trimethyl-2-tridecanol, Including the (2S,3S,7S,11R) and (2S,3S,7S,11S) Stereoisomers Identified as Pheromone Precursors in Females of the Pine Sawfly Microdiprion pallipes (Hymenoptera: Diprionidae)2001In: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, Vol. 2001, no 2, p. 353-363Article in journal (Refereed)
    Abstract [en]

    All sixteen stereoisomers of 3,7,11-trimethyl-2-tridecanol were synthesised in high stereoisomerical purities (> 95%), for use in the identification of the stereoisomers present in females of the pine sawfly Microdiprion pallipes (Fallen) (Hymenoptera: Diprionidae) as the precursor of the actual sex pheromone (which is the propionate), and also for investigation of the biological activities of the esters. The key step in the syntheses was the coupling of each of the enantiomers of cis-3,4-dimethyl-gamma -butyrolactone with each of the four pure stereoisomers of 1-lithio-2,6-dimethyloctanes. The four corresponding alcohols were obtained by lipase-catalysed (Amano PS) kinetic separation, based on selective acylation of either (2R/S,6S)- or (2R/S,GR)-2,6-dimethyl-1-octanol (obtained from the optically pure enantiomers of citronellal). Additionally, a mixture of the 16 possible stereoisomers of 3,7,11-trimethyl-2-tridecanol was also prepared.

  • 242.
    Larsson, Michael
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Ngyuen, Ba-Vu
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Hedenström, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Högberg, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Synthesis and Studies of the Stereoisomeric Composition in the Sex Pheromone of Microdiprion pallipes.: Poster och abstrakt. Euchem conference, Sundsvall.1998Conference paper (Other academic)
  • 243.
    Larsson, Niklas
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Mathematics and Science Education. Mid Sweden University, Faculty of Science, Technology and Media, Department of Mathematics and Science Education.
    Kemilaborationen i förändring: Sex erfarna lärares syn på hur laborationer förändrats över tid2019Independent thesis Advanced level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Denna forskningsrapport fokuserar på gymnasieskolans laborationer i kemi och hur dessa förändrats under de senaste 10-20 åren. Motivet till att studera detta är ambitionen att få ökad didaktisk förståelse för laborationen som viktigt inslag i kemiundervisningen. I ett större perspektiv kan detta vara av intresse för att analysera om förändringar av gymnasieskolans kemilaborationer kan utgöra en delförklaring till att svenska universitet upplever ett minskat söktryck för kemi på högskolenivå och om delförklaring kan finnas för att Sverige som nation inte når samma resultat i naturvetenskap som vissa andra länder i internationella kunskapsmätningar. Sex erfarna lärare från sex olika skolor har intervjuats om sina upplevelser av kemilaborationen och vad som påverkat dess utveckling. Ramfaktorteorin har varit grundläggande för detta arbete och som analysmetod har fenomenografin valts. Resultaten visar på en stor variation i vad lärare anser påverkat kemilaborationens förändring. Ökat medvetande och högre krav från lagar och förordningar inom säkerhetsområdet samt att lärare upplever sig ha mindre tillgänglig tid för laborationerna framstår som de tydligaste orsakerna till gjorda förändringar. Även kompensation för försämrade praktiska färdigheter hos elever som lämnar grundskolan framkommer som en bakomliggande faktor. Den nya läroplanen Gy 2011, kostnadsöverväganden och kemi­lokalernas beskaffenhet framkom som mindre avgörande för kemilaborationens utveckling.

  • 244.
    Lassance, J-M
    et al.
    Department of Biology, Lund University, 22362 Lund, Sweden.
    Groot, A T
    Department of Entomology, Max-Planck Institute for Chemical Ecology, 07745 Jena, Germany.
    Liénard, M A
    Department of Biology, Lund University, 22362 Lund, Sweden.
    Antony, B
    Department of Biology, Lund University, 22362 Lund, Sweden.
    Borgwardt, C
    Department of Entomology, Max-Planck Institute for Chemical Ecology, 07745 Jena, Germany.
    Andersson, Fredrik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Hedenström, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Heckel, D G
    Department of Entomology, Max-Planck Institute for Chemical Ecology, 07745 Jena, Germany.
    Löfstedt, C
    Department of Biology, Lund University, 22362 Lund, Sweden.
    Allelic variation in a fatty-acyl reductase gene causes divergence in moth sex pheromones2010In: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 466, no 7305, p. 486-489Article in journal (Refereed)
    Abstract [en]

    Pheromone-based behaviours are crucial in animals from insects to mammals, and reproductive isolation is often based on pheromone differences. However, the genetic mechanisms by which pheromone signals change during the evolution of new species are largely unknown. In the sexual communication system of moths (Insecta: Lepidoptera), females emit a species-specific pheromone blend that attracts males over long distances. The European corn borer, Ostrinia nubilalis, consists of two sex pheromone races, Z and E, that use different ratios of the cis and trans isomers of acetate pheromone components. This subtle difference leads to strong reproductive isolation in the field between the two races, which could represent a first step in speciation. Female sex pheromone production and male behavioural response are under the control of different major genes, but the identity of these genes is unknown. Here we show that allelic variation in a fatty-acyl reductase gene essential for pheromone biosynthesis accounts for the phenotypic variation in female pheromone production, leading to race-specific signals. Both the cis and trans isomers of the pheromone precursors are produced by both races, but the precursors are differentially reduced to yield opposite ratios in the final pheromone blend as a result of the substrate specificity of the enzymes encoded by the Z and E alleles. This is the first functional characterization of a gene contributing to intraspecific behavioural reproductive isolation in moths, highlighting the importance of evolutionary diversification in a lepidopteran-specific family of reductases. Accumulation of substitutions in the coding region of a single biosynthetic enzyme can produce pheromone differences resulting in reproductive isolation, with speciation as a potential end result.

     

     

  • 245.
    Laurén, Ari
    et al.
    Joensuu Unit, Finnish Forest Research Institute, P.O. Box 68, Joensuu 80101, Finland.
    Lappalainen, Mari
    Joensuu Unit, Finnish Forest Research Institute, P.O. Box 68, Joensuu 80101, Finland.
    Saari, Paivi
    Joensuu Unit, Finnish Forest Research Institute, P.O. Box 68, Joensuu 80101, Finland.
    Kukkonen, Jussi V. K.
    Department of Biology, University of Eastern Finland, P.O. Box 111, Joensuu 80101, Finland.
    Koivusalo, Harri
    Department of Civil and Environmental Engineering, Aalto University School of Engineering, P.O. Box 15200, Aalto 00076, Finland.
    Piirainen, Sirpa
    Joensuu Unit, Finnish Forest Research Institute, P.O. Box 68, Joensuu 80101, Finland.
    Setälä, Heikki
    Department of Environmental Sciences, University of Helsinki, Niemenkatu 73, Lahti 15140, Finland.
    Sarjala, Tytti
    Parkano Unit, Finnish Forest Research Institute, Kaironiementie 15, Parkano 39700, Finland.
    Bylund, Dan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Heinonen, Jaakko
    Joensuu Unit, Finnish Forest Research Institute, P.O. Box 68, Joensuu 80101, Finland.
    Nieminen, Mika
    Vantaa Unit, Finnish Forest Research Institute, P.O. Box 18, Vantaa 01301, Finland.
    Palviainen, Marjo
    Department of Forest Sciences, University of Helsinki, P.O. Box 27, Helsinki 00014, Finland.
    Launiainen, Samuli
    Joensuu Unit, Finnish Forest Research Institute, P.O. Box 68, Joensuu 80101, Finland.
    Finér, Leena
    Joensuu Unit, Finnish Forest Research Institute, P.O. Box 68, Joensuu 80101, Finland.
    Nitrogen and Carbon Dynamics and the Role of Enchytraeid Worms in Decomposition of L, F and H Layers of Boreal Mor2012In: Water, Air and Soil Pollution, ISSN 0049-6979, E-ISSN 1573-2932, Vol. 223, no 7, p. 3701-3719Article in journal (Refereed)
    Abstract [en]

    Decomposition of organic material releases carbon dioxide (CO2) into the atmosphere, and dissolved organic carbon (DOC), dissolved organic nitrogen (DON) and ammonium (NH4-N) into soil water. Each of the decomposition products contributes differently to overall export of carbon (C) and nitrogen (N) to water courses. Our aim was to study the quantity and composition of the released C and N as affected by the organic material and soil fauna, represented by enchytraeid worms. We measured the release rate of carbon dioxide, and calculated the release rates for DOC and dissolved N in soil from repeated measurements of DOC and N pools during laboratory incubation of litter (L), fermented (F) and humus (H) layers of boreal forest mor. The intermediate decomposition products, DOC and DON, were characterised according to the molecule size. The release rate of the decomposition products was higher for fresh than for old organic material. The majority of N and C were released as NH4-N and CO2, respectively. The amount of extractable organic N in soil decreased by time but DON increased. Enchytraeids stimulated N mineralisation and the release of large molecule size DOC, particularly in L layer. The results suggest that organic N in extractable form biodegrades effectively, and that soil fauna have an important role in the decomposition. The results were interpreted from the water quality point of view and the implications of the results to modelling of decomposition and export of DOC and dissolved N to recipient water bodies are discussed. In the modelling context, the novelty of the study is the description of the intermediate decomposition products and the division of the dissolved organic compounds into low molecular weight and high molecular weight fractions.

  • 246.
    Lebreton, Sebastien
    et al.
    Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Alnarp.
    Borrer-Echeverry, Felipe
    Biological Control Laboratory, Colombian Corporation of Agricultural Research, Las Palmas, Bogota, Colombia.
    Gonzalez, Francisco
    Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Alnarp.
    Solum, Marit
    Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Alnarp.
    Wallin, Erika
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Hedenström, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Hansson, Bill S
    Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Jena, Germany.
    Gustavsson, Anna-Lena
    Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Solna.
    Bengtsson, Marie
    Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Alnarp.
    Birgersson, Göran
    Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Alnarp.
    Walker, William B
    Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Alnarp.
    Dweck, Hany KM
    Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Jena, Germany; Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, USA.
    Becher, Paul G
    Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Alnarp.
    Witzgall, Peter
    Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Alnarp.
    A Drosophila female pheromone elicits species-specific long-range attraction via an olfactory channel with dual specificity for sex and food2017In: BMC Biology, ISSN 1741-7007, E-ISSN 1741-7007, Vol. 15, no 1, article id 88Article in journal (Refereed)
    Abstract [en]

    Background: Mate finding and recognition in animals evolves during niche adaptation and involves social signals and habitat cues. Drosophila melanogaster and related species are known to be attracted to fermenting fruit for feeding and egg-laying, which poses the question of whether species-specific fly odours contribute to long-range premating communication. Results: We have discovered an olfactory channel in D. melanogaster with a dual affinity to sex and food odorants. Female flies release a pheromone, (Z)-4-undecenal (Z4-11Al), that elicits flight attraction in both sexes. Its biosynthetic precursor is the cuticular hydrocarbon (Z,Z)-7,11-heptacosadiene (7,11-HD), which is known to afford reproductive isolation between the sibling species D. melanogaster and D. simulans during courtship. Twin olfactory receptors, Or69aB and Or69aA, are tuned to Z4-11Al and food odorants, respectively. They are co-expressed in the same olfactory sensory neurons, and feed into a neural circuit mediating species-specific, long-range communication; however, the close relative D. simulans, which shares food resources with D. melanogaster, does not respond to Z4-11Al. Conclusion: The Or69aA and Or69aB isoforms have adopted dual olfactory traits. The underlying gene yields a collaboration between natural and sexual selection, which has the potential to drive speciation.

  • 247.
    Lidenmark, Cecilia
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Pettersson, Torbjörn
    KTH Royal Inst Technol, SE-10044 Stockholm, Sweden.
    Karlsson, Ola. J.
    Lund University, Lund, Sweden.
    Notley, Shannon M.
    Australian National University, Canberra, Australia.
    Edlund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    The adhesive behavior of extracted Latex polymers towards Silicon oxide and Cellulose2013In: International Journal of Adhesion and Adhesives, ISSN 0143-7496, E-ISSN 1879-0127, Vol. 44, p. 250-258Article in journal (Refereed)
    Abstract [en]

    The objective with this work is to compare the adhesive behavior for latex polymers of different Glass transition Temperatures (Tg) at different length scales and with different contact times. This is accomplished by two techniques: AFM colloidal probe force measurements and JKR-measurements. The aim is to compare the results from these two techniques and relate them to the interaction of the latex polymers towards oxidized silicon wafers and silica/cellulose probes. Theory suggests that altering the short timeframes used in the colloidal probe technique does not affect the ranking of the adhesion for the different polymers, but for the macroscopic JKR-technique it influences the measured work of adhesion. It is therefore important to let the system reach a steady state before assuming complete spreading and adhesion. AFM and JKR measurements showed the same trends where the polymer with lowest content of styrene has the lowest Tg and the highest adhesion, due to the larger polymer chain mobility.

  • 248.
    Liedtke, H. Christoph
    et al.
    Lund Univ, Dept Ecol, S-22362 Lund, Sweden.
    Åbjörnsson, Kajsa
    Lund Univ, Dept Ecol, S-22362 Lund, Sweden.
    Harraca, Vincent
    Lund Univ, Dept Ecol, S-22362 Lund, Sweden.
    Knudsen, Jette
    Lund Univ, Dept Ecol, S-22362 Lund, Sweden.
    Wallin, Erika
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Hedenström, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Ryne, Camilla
    Lund Univ, Dept Ecol, S-22362 Lund, Sweden.
    Alarm pheromones and chemical communication in nymphs of the tropical bed bug Cimex hemipterus (Hemiptera: Cimicidae)2011In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 6, no 3, p. e18156-Article in journal (Refereed)
    Abstract [en]

    The recent resurge of bed bug infestations (Cimex spp.; Cimicidae) and their resistance to commonly used pesticides calls for alternative methods of control. Pheromones play an important role in environmentally sustainable methods for the management of many pest insects and may therefore be applicable for the control of bed bugs. The tropical bed bug, Cimex hemipterus, is a temporary ectoparasite on humans and causes severe discomfort. Compared to the common bed bug, Cimex lectularius, little is known about the chemical signalling and pheromone-based behaviour of the tropical species. Here, we show that the antennal morphology and volatile emission of C. hemipterus closely resembles those of C. lectularius and we test their behavioural responses to conspecific odour emissions. Two major volatiles are emitted by male, female and nymph C. hemipterus under stress, (E)-2-hexenal and (E)-2-octenal. Notably, nymph emissions show contrasting ratios of these compounds to adults and are further characterized by the addition of 4-oxo-(E)-2-hexenal and 4-oxo-(E)-2-octenal. The discovery of this nymph pheromone in C. hemipterus is potentially the cause of a repellent effect observed in the biotests, where nymph odours induce a significantly stronger repellent reaction in conspecifics than adult odours. Our results suggest that pheromone-based pest control methods developed for C. lectularius could be applicable to C. hemipterus, with the unique nymph blend showing promising practical properties.

  • 249. Lin, Guoqiang
    et al.
    Hjalmarsson, Mats
    Högberg, Hans-Erik
    Jernstedt, Karen
    Norin, Torbjörn
    Asymmetric Synthesis of 2-alkylalkanoic acids via Alkylation of Chiral Amide Anions.1984In: Acta Chemica Scandinavica, ISSN 0904-213X, E-ISSN 1902-3103, Vol. B38, p. 795-801Article in journal (Refereed)
  • 250. Lin, Guoqiqng
    et al.
    Högberg, Hans-Erik
    Norin, Torbjörn
    Asymmetric Synthesis of 2-Alkylalkanoic Acids via Alkylation of Chiral Amide Anions1984In: Chinese Science Bulletin (Kexue Tongbao -English version), ISSN 1001-6538, Vol. 29, no 5, p. 632-634Article in journal (Refereed)
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