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Sökning: LAR1:miun > Högberg Hans Erik

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  • Anderbrant, Olle, et al. (författare)
  • Field Response of Male Pine Sawflies, Neodiprion sertifer (Diprionidae), to Sex Pheromone Analogs in Japan and Sweden.
  • 2010
  • Ingår i: Journal of Chemical Ecology. - Springer. - 1573-1561. ; 36, s. 969-977
  • Tidskriftsartikel (refereegranskat)abstract
    • The pine sawfly Neodiprion sertifer (Geoffroy) uses the acetate or propionate of (2S,3S,7S)-3,7-dimethyl-2-pentadecanol (diprionol) as pheromone components, with the (2S,3R,7R)-isomer being antagonistic, synergistic, or inactive according to the population tested. In this study, we tested the attraction of males to the acetates of three analogs of diprionol, each missing one methyl group, viz. (2S,7S)-7-methyl-2-pentadecanol, (2S,6S)-2,6-dimethyl-1-tetradecanol, and (2S,3S)-3-methyl-2-pentadecanol. None of the analogs alone, or in combination with diprionol acetate, was attractive in Sweden, even at 100 times the amount of diprionol acetate attractive to N. sertifer. In Japan, the acetate of (2S,3S)-3-methyl-2-pentadecanol attracted males when tested in amounts 10-20 times higher than the acetate pheromone component. The acetate esters of the (2S,3R)-analog and the (2S,3R,7R)-isomer of diprionol also were tested in combination with the pheromone compound (acetate ester). Both compounds caused an almost total trap-catch reduction in Sweden, whereas in Japan they appear to have relatively little effect on trap capture when added to diprionol acetate. Butyrate and iso-butyrate esters of diprionol were unattractive to N. sertifer in Sweden. In summary, there exists geographic variation in N. sertifer in responses to both diprionyl acetate and some of its analogs.
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  • Anderbrant, Olle, et al. (författare)
  • Pheromone mating disruption of the pine sawfly Neodiprion sertifer : : is the size of the treated area important?
  • 2002
  • Ingår i: Iobc/Wprs Bulletin. - Monfavet. - 1027-3115. ; 25:9, s. 111-116
  • Tidskriftsartikel (övrigt vetenskapligt)abstract
    • Few attempts to control forest insects by means of pheromone mating disruption have<br /> been reported. The first such experiments with the European pine sawfly, Neodiprion sertifer<br /> (Hymenoptera: Diprionidae), resulted in nearly complete trap catch reduction, but no effects on<br /> population density or sex ratio were noted. Unmated females lay eggs, which develop into males<br /> only. Therefore, if mating disruption would be successful, a more male-biased sex ratio is<br /> expected the next generation. One possible explanation for the early results is that mated females<br /> disperse into the treated area, and thus obscure the effects of the treatment. In order to reduce the<br /> effect of such immigrating females, the treated area was increased in the experiment described<br /> here from the earlier used 0.5 – 4 ha to 25 ha. The acetate of erythro-3,7-dimethyl-2-<br /> pentadecanol was used for disruption and released from dispensers every 10 m. The influence on<br /> male orientation was monitored by pheromone traps, baited with the acetate of (2S,3S,7S)-3,7-<br /> dimethyl-2-pentadeanol and placed at 100 m interval along two perpendicular, 1500 m lines<br /> intersecting the treated area. The trap catch reduction was near 100% during the first month, but<br /> then declined to around 90% during the second month. Mating frequencies were checked by<br /> comparing the sex ratio of the next generation from within and outside the treatment area. No<br /> effect of the treatment on the sex ratio was detected, and the frequency of mated females could be<br /> assumed to be independent of treatment. Alternative hypotheses to explain the failure of<br /> pheromone mating disruption in N. sertifer are discussed.
6.
  • Anderbrant, Olle, et al. (författare)
  • Release of sex pheromone and its precursors in the pine sawfly Diprion pini (Hym., Diprionidae)
  • 2005
  • Ingår i: Chemoecology. - Birkhaüser. - 1423-0445 .- 0937-7409. ; 15:3, s. 147-151
  • Tidskriftsartikel (refereegranskat)abstract
    • The first identification of a sex pheromone of a pine sawfly (Hymenoptera, Diprionidae) dates back almost thirty years. Since then, female-produced pheromones of over twenty diprionid species have been investigated by solvent extraction followed by separation and identification. However, no study has shown what the females actually release. Collection of airborne compounds using absorbtion on charcoal filter as well as solid phase microextraction (SPME) followed by analysis employing gas chromatography combined with mass spectrometry (GC-MS), revealed an unusual system in Diprion pini, in which the pheromone precursor alcohol, 3,7-dimethyl-2-tridecanol, is released together with acetic, propionic, butyric and isobutyric acids. The corresponding acetate, propionate and butyrate esters of 3,7-dimethyl-2-tridecanol were also found in the samples. All esters were electrophysiologically active, and the propionate and isobutyrate were attractive in trapping experiments. Based on these and earlier reported results, it seems that at least in part of its range, the pheromone response of D. pini is not very specific with regard to the functional group, as long as this is an ester.
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  • Anderbrant, Olle, et al. (författare)
  • Sex Pheromone of the Introduced Pine Sawfly, Diprion similis (Diprionidae), Revisited: No Activity of Earlier Reported Synergists
  • ????
  • Annan publikation (övrigt vetenskapligt)abstract
    • Extracts of Diprion similis females were found to contain about 15 ng of the sex pheromone precursor 3,7-dimethylpentadecan-2-ol per female. When analysing the extracts after derivatisation with (2S)-2-acetoxypropionyl chloride, we found that the major stereoisomer in the extract was (2S,3R,7R)-3,7-dimethylpentadecan-2-ol. Also other stereoisomers of 3,7-dimethylpentadecan-2-ol were identified in the extract namely, 1% of (2R,3S,7S) , 0.3% (2R,3R,7R) and 0.4% of (2R,3R,7S). An unknown fifth substance showed an identical spectrum to 3,7-dimethylpentadecan-2-ol, both in SIM and full scan mode. In field tests in Ontario, Canada, the earlier identified main pheromone component, viz. the propanoate of (2S,3R,7R)-3,7-dimethylpentadecan-2-ol, was tested alone and in combination with other stereoisomers, earlier reported to be synergistic. In none of the tests were any synergistic effects detected and the threo four-isomer blend was as attractive as the pure main compound. Thus, one of the few examples of a diprionid sawfly using more than one substance in its sex pheromone could not be confirmed. The results also suggest that monitoring programs can use the more easily synthesized threo-blend without losing efficiency.
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  • Berglund, Per, et al. (författare)
  • 2-Methylalkanoic acids resolved by esterification catalysed by lipase from Candida rugosa : Alcohol chain length and enantioselectivity
  • 1993
  • Ingår i: Tetrahedron Asymmetry. - 09574166 (ISSN). ; 4:8, s. 1869-1878
  • Tidskriftsartikel (refereegranskat)abstract
    • Enantiomerically pure (R)-2-methyldecanoic acid and (S)-2-methyl-1-decanol were prepared in a multi gram scale by esterification reactions catalysed by lipase from Candida rugosa. The enantiomeric ratios (E-values) were determined as a function of the chain length of the alcohol used as the complementary substrate in cyclohexane. In the resolution of 2-methyldecanoic acid the highest value (E = 37 ± 5) was obtained, when either 2-hexanol, 1-heptanol or 1-octanol were used. In contrast, when resolving 2-methyloctanoic acid, the E-values increased continually with increasing chain length of the alcohol used. 1-Hexadecanol gave the highest value: E &gt; 100. The E-values were determined from the enantiomeric excess (ee) of the product at a conversion below 0.4. After two consecutive esterification reactions enantiomerically pure (R)-2-methyldecanoic acid, &gt;99.8% ee, and after subsequent reduction of the ester produced, (S)-2-methyl-1-decanol, 96.7% ee, were obtained.
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  • Berglund, Per, et al. (författare)
  • Alcohols as enantioselective inhibitors in a lipase catalysed esterification of a chiral acyl donor
  • 1995
  • Ingår i: Biotechnology Letters. - 01415492 (ISSN). ; 17:1, s. 55-60
  • Tidskriftsartikel (refereegranskat)abstract
    • Increased reaction rates and increased enantioselectivities were observed with decreased concentrations of n-alkanols when resolving 2-methyldecanoic acid by esterification catalysed by immobilised lipase from Candida rugosa at controlled water activities in cyclohexane. The enantioselectivity was found to be independent of the water activity in the reaction medium at the n-heptanol concentrations investigated. However, when n-decanol was used as the acyl acceptor, not only the alcohol concentration but also the water activity in the reaction medium, influenced the enantioselectivity. The results obtained showed that the low enantioselectivity seen at a high alcohol concentration could be explained by the alcohol influencing the apparent V(max)(S) and V(max)(R) differently.
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