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Träfflista för sökning "WFRF:(Hansson Christer) srt2:(1985-1989)"

Sökning: WFRF:(Hansson Christer) > (1985-1989)

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1.
  • Baker, Thomas C., et al. (författare)
  • Adaptation of antennal neurons in moths is associated with cessation of pheromone-mediated upwind flight
  • 1988
  • Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424. ; 85:24, s. 9826-9830
  • Tidskriftsartikel (refereegranskat)abstract
    • A wind-borne plume of sex pheromone from a female moth or a synthetic source has a fine, filamentous structure that creates steep and rapid fluctuations in concentration from a male moth flying up the plume's axis. The firing rates from single antennal neurons on Agrotis segetum antennae decreased to nearly zero within seconds after the antennae were placed in a pheromone plume 70 cm downwind of a high-concentration source known from previous studies to cause in-flight arrestment of upwind progress. In a separate experiment, the fluctuating output from chilled neurons on Grapholita molesta antennae became attenuated in response to repetitive, experimentally delivered pheromone pulses. The attenuation was correlated with a previously reported higher percentage of in-flight arrestment exhibited by moths flying at cooler compared to warmer temperatures. These results indicate that two peripheral processes related to excessive concentration, complete adaptation of antennal neurons, or merely the attenuation of fluctuations in burst frequency, are important determinants of when upwind progress by a moth flying in a pheromone plume stops and changes to station keeping. Also, adaptation and attenuation may affect the sensation of blend quality by preferentially affecting cells sensitive to the most abundant components in airborne pheromone blends.
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2.
  • Baker, Thomas C., et al. (författare)
  • Adaptation of male moth antennal neurons in a pheromone plume is associated with cessation of pheromone-mediated flight
  • 1989
  • Ingår i: Chemical Senses. - : Oxford University Press (OUP). - 0379-864X .- 1464-3553. ; 14:3, s. 439-448
  • Tidskriftsartikel (refereegranskat)abstract
    • Recordings of the firing rates of single antennal neurons when Agrotis segetum antennac were placed 70 cm downwind of a pheromone source revealed that cells sensitive to the most volatile component adapted rapidly in a plume from a high-concentration source known from previous studies to cause in-flight arrestment of progress towards the source. No adaptation was found in response to lower-concentration plumes known to promote high levels of sustained flight to the source with little premature arrestment. Adaptation was not observed in antennal neurons of a second species, Heliothis virescens, when they were placed in plumes of this species' sex pheromone blend, regardless of the concentration. In flight-tunnel tests these same pheromone sources evoked high levels of source location with little arrestment. These results indicate that adaptation or attenuation of antennal neuronal burst frequencies in response to rapidly arriving pheromone filaments in a plume may be important peripheral determinants of whether or not prolonged upwind flight and successful pheromone source location occurs.
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3.
  • Baker, T. C., et al. (författare)
  • Isolation, identification and synthesis of sex pheromone components of the carob moth, Ectomyelois ceratoniae
  • 1989
  • Ingår i: Tetrahedron Letters. - 0040-4039. ; 30:22, s. 2901-2902
  • Tidskriftsartikel (refereegranskat)abstract
    • The sex pheromone of females of the carob moth, Ectomyelois ceratoniae, was identified to be a mixture of (Z,E)-9,11,13-tetradecatrienal, (Z,E)-9,11-tetradecadienal and (Z)-9-tetradecenal in the ratio of 10:1:1. A synthetic blend proved to be attractive. GC/EAD + GC/MS investigations showed (Z,E)-9,11,13-tetradecatrienal, (Z,E)-9,11-tetradecadienal and (Z)-9-tetradecenal to be the sex pheromone of the carob moth. Blends of synthetic compounds are active.
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6.
  • Hansson, Bill S., et al. (författare)
  • Z‐linked inheritance of male olfactory response to sex pheromone components in two species of tortricid moths, Ctenopseustis obliquana and Ctenopseustis sp
  • 1989
  • Ingår i: Entomologia Experimentalis et Applicata. - : Wiley. - 0013-8703. ; 53:2, s. 137-145
  • Tidskriftsartikel (refereegranskat)abstract
    • The olfactory response from male pheromone sensitive sensilla was investigated in the endemic New Zealand brownheaded leafrollers Ctenopseustis obliquana (Walker) and C. sp. ‘ropeana' (Lepidoptera, Tortricidae). The responses from 281 sensilla from the parental strains and from both the reciprocal crosses, including F1, F2 and maternal and paternal backcrosses were recorded, and statistically analysed using a multivariate analysis. In males of both the parental strains, a large amplitude cell responded to the main pheromone component of the conspecific female, in C. obliquana (Z)‐8‐tetradecenyl acetate (Z8–14:OAc) and in C. sp ‘ropeana' (Z)‐5‐tetradecenyl acetate (Z5–14:OAc). Both male types also possessed a small amplitude cell, which in C. obliquana responded weakly to Z5–14: OAc and tetradecyl acetate (14: OAc), and in C. sp ‘ropeana' responded to Z8–14: OAc. The responses from the different types of hybrid males were more variable than the responses from parental males. A main pattern could, however be seen, corresponding with the expected pattern in a sex‐linked inheritance on the Z‐chromosome of a C. sp ‘ropeana' type dominant genetic factor. The more pronounced variation in the hybrids could not be explained by this model, and might be due to the involvement of additional genes. Liaison avec le chromosome Z de l'hérédité des réponses olfactives à la composition de la phéromone sexuelle chez deux tordeuses: Ctenopseustis obliquana et C. sp. ‘ropeana' Les réactions olfactives des sensilles mâles sensibles aux phéromones ont été examinées par enregistrement de l'extrémité de la sensille chez les tordeuses C. obliquana Walker et C. sp. ‘ropeana'. Les enregistrements ont porté sur 281 sensilles des lignées parentales et des croisements réciproques de F1, F2 et de croisements en retour maternel et paternel. Les résultats des enregistrements d'une sensille ont été soumis à une analyse en composantes principales. Chez les mâles de chaque lignée parentale un seul type physiologique de sensille a été découvert; une cellule répond par un pic grand au principal constituant de la phéromone femelle conspécifïque. (Z)‐8‐acétate tétradécényl (Z8–14:OAc) pour C. obliquana, et (Z)‐5‐acétate tétradécényl (Z5–14:OAc) pour C. sp. ‘ropeana'. Une seconde type de cellule dans les sensilles des deux espèces de mâles présente un pic petit pour Z5–14: OAc et pour l'acétate tétradécyl (14: OAc) chez C. obliquana, et pour C. sp. ‘ropeana' au Z8–14:OAc. Les réponses des sensilles des différents types de mâles hybrides sont plus hétérogènes que celles des sensilles de leurs pères. Un schéma général pourrait cependant être décelé, correspondant au schéma prévu avec une hérédité d'un facteur dominant liée au sexe sur le chromosome Z de C. sp. ‘ropeana’. La variation plus accentuée chez les hybrides ne peut être expliquée par ce modèle, et pourrait impliquer des gènes additionnels. 1989 The Netherlands Entomological Society
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8.
  • Hansson, Christer (författare)
  • Some indolic compounds as markers of the melanocyte activity
  • 1988
  • Ingår i: Acta dermato-venereologica. Supplementum. - 0365-8341. ; 138, s. 1-60
  • Tidskriftsartikel (refereegranskat)abstract
    • The melanocyte activity was studied by analysis of the urinary excretion of indolic and cysteinyldopa compounds. One eumelanin marker, 5,6-dihydroxy-indole-2-carboxylic acid was identified and quantified in normal urine. However, its low concentration and sensitivity to oxidation made it less suitable for clinical studies. A methylated derivative of this substance, 6-hydroxy-5-methoxyindole-2-carboxylic acid (6H5MI-2-C), was also demonstrated in normal urine. A quantitative method was worked out and the normal urinary concentration of this substance was as high as the concentration of 5-S-cysteinyldopa. The concentrations of the eumelanic marker 6-hydroxy-5-methoxyindole-2-carboxylic acid and the pheomelanic marker 5-S-cysteinyldopa were determined in the urine of psoriasis patients during PUVA treatment and also in the urine of subjects with different skin colour. The melanocyte activity in albinotic patients and in albinotic mice was studied by the same technique. Some in vitro experiments were performed to show that 5-S-glutathionyldopa has the molecular properties of forming a mercapto-substituted indole derivative. The following main conclusions were drawn: 1. 5,6-Dihydroxyindole-2-carboxylic acid and 6-hydroxy-5-methoxyindole-2-carboxylic acid are both present in measurable amounts in normal urine. 2. The urinary concentration of 6-hydroxy-5-methoxyindole-2-carboxylic acid increased during PUVA treatment in a similar way as for 5-S-cysteinyldopa. 3. The eumelanic marker 6-hydroxy-5-methoxyindole-2-carboxylic acid was excreted in larger quantities by people with genetically dark skin, whereas the pheomelanic marker 5-S-cysteinyldopa was not related to pigment type. 4. In the urine of one albino patient and in the urine of albinotic mice a total absence of 6-hydroxy-5-methoxyindole-2-carboxylic acid was found. The urinary concentrations of 5-S-cysteinyldopa in these subjects were measurable but lower than in pigmented subjects. Thus, 6-hydroxy-5-methoxy-indole-2-carboxylic acid seems to be a more specific melanocyte marker than the cysteinyldopas.
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9.
  • Hansson, Elisabeth, et al. (författare)
  • 5-Hydroxytryptamine stimulates the formation of inositol phosphate in astrocytes from different regions of the brain
  • 1987
  • Ingår i: Neuropharmacology. - 1873-7064. ; 26:9, s. 1377-1382
  • Tidskriftsartikel (refereegranskat)abstract
    • 5-Hydroxytryptamine (5-HT) stimulated the turnover of phosphoinositide in primary cultures of astroglia from the cerebral cortex, striatum, hippocampus and brain stem. Ketanserin and ritanserin, selective antagonists for the central 5-HT2 receptor, inhibited the 5-HT-stimulated formation of inositol monophosphate. In contrast, there was no statistically significant accumulation of cyclic AMP after incubation with different concentrations of 5-HT in any of the cultures studied. The results indicate that astrocytes from various regions of the brain possess 5-HT2 receptors coupled to the formation of inositol phosphates.
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10.
  • Kagedal, Bertil, et al. (författare)
  • Automated high-performance liquid chromatographic determination of 5-S-cysteinyl-3,4-dihydroxyphenylalanine in urine
  • 1989
  • Ingår i: Journal of Chromatography A. - 0021-9673. ; 473, s. 359-370
  • Tidskriftsartikel (refereegranskat)abstract
    • An automated high-performance liquid chromatographic (HPLC) method has been developed for measurement of 5-S-cysteinyl-DOPA in urine (DOPA = 3,4-dihydroxyphenylalanine). The urinary sample was injected into an HPLC boronate column. With a mobile phase of 0.1 M phosphate buffer containing 0.2 mM disodium ethylenediaminetetraacetate (Na2EDTA) (pH 6.0) mixed with methanol (9:1), 5-S-cysteinyl-DOPA was adsorbed while most other compounds were washed away. By column switching, the column flow was reversed and 5-S-cysteinyl-DOPA was desorbed by a mobile phase of 0.1 M formic acid and 0.2 mM Na2EDTA at pH 3.0 and chromatographed on a reversed-phase column. The precision, as estimated from repeated analysis of an urinary sample and from duplicate analysis of a number of samples, ranged from 1.4 to 5.2% (coefficient of variation), and the analytical recovery was 93 +/- 4.1%. The method is suitable for use in the clinical laboratory.
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