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| 2. |
- Hill, Sharon, et al.
(författare)
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Characterization of Antennal Trichoid Sensilla from Female Southern House Mosquito, Culex quinquefasciatus Say
- 2009
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Ingår i: Chemical Senses. - : Oxford University Press (OUP). - 0379-864X .- 1464-3553. ; 34, s. 231-252
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Tidskriftsartikel (refereegranskat)abstract
- Culex quinquefasciatus, the southern house mosquito, is highly dependent on its olfactory system for vector-related activities such as host seeking and oviposition. The antennae are the primary olfactory organs in mosquitoes. We describe 5 morphological types of sensilla on the antenna of C. quinquefasciatus: 1) a pair of sensilla coeloconica located at the distal tip, 2) long and short sensilla chaetica present on all 13 antennal flagella, 3) sensilla ampullacea found on the 2 proximal-most flagella, 4) 2 morphological types of grooved pegs dispersed throughout the flagella, and 5) 5 morphological subtypes of sensilla trichodea distributed among all flagella. Antennal trichoid and grooved peg sensilla of mosquitoes have been demonstrated to house the olfactory receptor neurons (ORNs) that detect many of the odors involved in eliciting vector-related behaviors. In order to initiate the functional characterization of the peripheral olfactory system in female C. quinquefasciatus, we mapped the physiological responses of all 5 morphological subtypes of sensilla trichodea to an odor panel of 44 behaviorally relevant odor compounds. We identified 17 functional classes of sensilla trichodea: 3 short sharp-tipped, 9 short blunt-tipped type I, and 5 short blunt-tipped type II sensilla. One morphological subtype remains unclassified as the long sharp-tipped sensilla did not respond to any of the volatiles tested. The functional classes of the ORNs were analyzed with respect to stimulus response profiles, stimuli sensitivity, and temporal coding patterns. Comparisons with other functionally classified mosquito antennal sensilla trichodea are discussed.
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| 4. |
- Ignell, Rickard, et al.
(författare)
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Presynaptic peptidergic modulation of olfactory receptor neurons in Drosophila.
- 2009
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 106:31, s. 13070-13075
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Tidskriftsartikel (refereegranskat)abstract
- The role of classical neurotransmitters in the transfer and processing of olfactory information is well established in many organisms. Neuropeptide action, however, is largely unexplored in any peripheral olfactory system. A subpopulation of local interneurons (LNs) in the Drosophila antannal lobe is peptidergic, expressing Drosophila tachykinins (DTKs). We show here that olfactory receptor neurons (ORNs) express the DTK receptor (DTKR). Using two-photon microscopy, we found that DTK applied to the antennal lobe suppresses presynaptic calcium and synaptic transmission in the ORNs. Furthermore, reduction of DTKR expression in ORNs by targeted RNA interference eliminates presynaptic suppression and alters olfactory behaviors. We detect opposite behavioral phenotypes after reduction and over expression of DTKR in ORNs. Our findings suggest a presynaptic inhibitory feedback to ORNs from peptidergic LNs in the antennal lobe.
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| 5. |
- Ignell, Rickard, et al.
(författare)
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Så släcks myggans blodtörst
- 2009
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Ingår i: Forskning och framsteg. - 0015-7937. ; 44, s. 22-26
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Tidskriftsartikel (populärvet., debatt m.m.)
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| 7. |
- Winther, Åsa M E, et al.
(författare)
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Peptidergic signaling in the antennal lobe modulates olfaction
- 2007
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Ingår i: 20th European Drosophila Research Coference.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The dtk gene in Drosophila encodes five different neuropeptides designated Drosophila tachykinins (DTK 1-5) that are expressed in about 100 neurons in the brain. Two tachykinin receptors (DTKR and NKD) have been identified in Drosophila. Specific neurons of the antennal lobe (AL), the primary center for olfactory processing in the Drosophila brain, express DTKs and the receptor DTKR. The DTKs are colocalized with the inhibitory transmitter GABA in many of the local interneurons (LNs) of the AL. We have investigated the roles of DTKs and DTKR in olfactory behavior by interfering with DTK signaling. By employing the Gal4/UAS system we have directed overexpression or knock-down (using RNAi) of peptides or receptor to different neuron types of the AL. Olfactory behavior was tested in a trap-assay based on a choice of odorant or control. We tested flies with DTK deficiency in two different partly overlapping populations of LNs. We also tested flies that are virtually DTK null (driving the RNAi construct with the pan-neural elav-Gal4). DTK deficient flies were less attracted to some of the odors tested. To study the role of the DTKR we used Gal4 lines that drive expression in olfactory receptor neurons (ORNs), LNs and in projection neurons to overexpress (OE) or down-regulate the receptor. DTKR-OE in the ORNs resulted in flies more repelled (or less attracted) to some of the odors tested. DTKR-OE in a subpopulation of the LNs produced flies with the same behavioral phenotype. Flies with DTKR deficiency in the ORNs and LNs were more attracted to odors. Our results suggest that DTKs and DTKR are involved in the modulation of the response to odors at the levels of ORNs and LNs, possibly by modulating the inhibitory activity of GABA.
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