Drosophila olfactory organs

Shanbhag S. R., Hekmat-Scafe D., Kim M. S., Park S. K., Carlson J. R., Pikielny C., Smith D. P. and Steinbrecht R. A. (2001a) Expression mosaic of odorant-binding proteins in Drosophila olfactory organs. Microsc. Res. Tech. 55, 297-306. 

Park S. K., Shanbhag S. R., Wang Q., Hasan G., Steinbrecht R. A. and Pikielny C. W. (2000) Expression patterns of two putative odorant-binding proteins in the olfactory organs of Drosophila melanogaster have different implications for their functions. Cell Tissue Res. 300, 181-197. 

Shanbhag S. R., Muller B. and Steinbrecht R. A. (1999) Atlas of olfactory organs of Drosophila melanogaster. I. Types, external organization, innervation and distribution of olfactory sensilla. Int. J. Insect Morphology Embryology 28, 377-397. 

Lansky P and Rospars J.-P (1993) Coding of odor intensity. Biosystems 31, 15-38. Ledent V., Gaillard F., Gautier P, Ghysen A. and Dambly-Chaudiere C. (1998) Expression and function of tap in the gustatory and olfactory organs of Drosophila. Int. J. Dev. Biol. 42, 163-170. 

Raha D. and Carlson J. R. (1994) OS9 a novel olfactory gene of Drosophila expressed in two olfactory organs. J. Neurobiol. 25, 169-184. 

Reddy G. V., Gupta B., Ray K. and Rodrigues V. (1997) Development of the Drosophila olfactory sense organs utilizes cell-cell interactions as well as lineage. Development 124, 703-712. 

Couto A., Alenius, M. and Dickson, B. J. (2005). Molecular, anatomical, and functional organization of the Drosophila olfactory system. Curr. Biol., 15,1535-1547. 

The diverse morphology of the olfactory organ among insect species provides a basis upon which classification has been based. Basically, the olfactory organ in the adult insect comprises two components on the head the antenna and the maxillary palp (Fig. la). Numerous sensilla cover the surface of the antennae and prevent direct contact of ORNs with the external environment. Each sensillum is filled with a potassium- and protein-rich fluid called sensillum lymph and houses one to four ORN dendrites. The small pits on the cuticle surfaces of sensilla allow contact of the ORN dendrite with volatile odorants that dissolve in the lymph. In Drosophila, the third segment of the antenna and of the maxillary palp possess approximately 1,200 and 120 ORNs, respectively. 

Consistent with the drastic change in food preference after metamorphosis, the expression pattern of ORs in the adult insect olfactory organ differs from that in the larval olfactory organ and also shows sexual dimorphism. In Drosophila, the adult expresses 40 ORs, 30 of which are expressed in antennae. Larvae express 25 ORs (Fishilevich et al. 2005 Kreher et al. 2005), 14 of which are larva-specific. As described below, a subset of adult-specific ORs responds to food odors, whereas ten of the 30 adult-specific ORs are specifically expressed in trichoid sensilla and are strongly inhibited or only weakly activated by food-related odors, consistent with then-purported role in pheromone rather than food detection. ORs expressed specifically at each developmental stage are likely to be essential for survival during the stage. 

Couto A, Alenius M, Dickson BJ (2005) Molecular, anatomical, and functional organization of the Drosophila olfactory system. Curr Biol 15 1535-1547 Crittenden JR, Skoulakis EM, Han KA, Kalderon D, Davis RL (1998) Tripartite mushroom body architecture revealed by antigenic markers. Learn Mem 5 38-51 Dahanukar A, Foster K, van der Goes van Naters WM, Carlson JR (2001) A Gr receptor is required for response to the sugar trehalose in taste neurons of Drosophila. Nat Neurosci 4 1182-1186 Dahanukar A, Lei Y-T, Kwon JY, Carlson JR (2007) Two Gr genes underlie sugar reception in Drosophila. Neuron 56 503-516... 

DEBRUYNE, M., CLYNE, P.J., CARLSON, J.R., Odor coding in a model olfactory organ The Drosophila maxillary palp, J. Neuroscl, 1999, 19, 4520-4532. 

Oppliger F., Guerin P. and Vlimant M. (2000) Neurophysiological and behavioral evidence for an olfactory function for the dorsal organ and a gustatory one for the terminal organ in Drosophila melanogaster larvae. J. Insect. Physiol. 46, 135-144. 

Gupta B. P. and Rodrigues V. (1997) atonal is a proneural gene for a subset of olfactory sense organs in Drosophila. Genes to Cell 2, 225-233. 

Gupta B. P., Flores G. V., Baneijee U. and Rodrigues V. (1998) Patterning an epidermal field Drosophila lozenge, a member of the AML- 1/Runt family of transcription factors, specifies olfactory sense organ type in a dose-dependent manner. Dev. Biol. 203, 400-411. 

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