XVI International Symposium on Olfaction and Taste - ecro

<strong>XVI</strong> <strong>International</strong> <strong>Symposium</strong> on Olfaction and Taste
direct role on our cellular immune system, and thus put TAAR signaling in leukocytes into the focus of amine intolerance
and food safety.
Poster session II Poster #226
Untypical connectivity from olfactory sensory neurons expressing OR37 into higher brain centers
visualized by genetic tracing
Andrea Bader 1 , Heinz Breer 1 and Jörg Strotmann 1
1 University of Hohenheim, Institute of Physiology, Stuttgart, Germany
strotman@uni-hohenheim.de
The OR37 subfamily of odorant receptors (OR) exists exclusively in mammals. In contrast to ORs in general, they are
highly conserved within and across species. These unique features raise the question, whether olfactory information
gathered by the OR37 sensory cells is processed in specially designated brain areas. To elucidate the wiring of projection
neurons from OR37 glomeruli into higher brain areas, tracing experiments were performed. The application of DiI onto the
ventral area of the olfactory bulb, which harbors the OR37 glomeruli, led to the labeling of fibers not only in the typical
olfactory cortical regions, but also in the medial amygdala and the hypothalamus. To visualize the projections from a
defined OR37 glomerulus more precisely, transgenic mice were studied in which olfactory sensory neurons co- express
the receptor subtype OR37C and the transsynaptic tracer Wheat Germ Agglutinin (WGA). WGA became visible not only
in the OR37C sensory neurons and the corresponding OR37C glomerulus, but also in cell somata located in the
mitral/tufted cell layer adjacent to the OR37C glomerulus, indicating a transfer of WGA onto projection neurons. In the
brain, WGA immunoreactivity was not detectable in typical olfactory cortical areas, but instead in distinct areas of the
medial amygdala. Detailed mapping revealed that the WGA immunoreactivity was restricted to the posterior-dorsal
subnucleus of the medial amygdala. In addition, WGA immunoreactivity was visible in some well circumscribed areas of
the hypothalamus. These results are indicative for a unique connectivity from OR37C sensory cells into higher brain
centers.
This work was supported by the Deutsche Forschungsgemeinschaft
Contributed talks VI “Interactions” Monday 25 June
Attraction of female Anopheles stephensi mosquitoes to the spores of entomopathogenic and nonentomopathogenic
fungi
Thomas C Baker 1 , Justine George 1 , Nina Jenkins 1 , Simon Blanford 1 and Matthew B Thomas 1
1Penn State University, Dept. of Entomology, University Park, PA, USA
tcb10@psu.edu
We performed behavioral Y-tube olfactometer assays in the laboratory to test the upwind flight responses of the
mosquito, Anopheles stephensi a major vector of human malaria in Asia, toward the fungal spores of two
entomopathogenic species, Beauveria bassiana and Metarhizium acridum. Our group has been working toward the goal of
applying spores to various indoor surfaces of dwellings in order to cause mosquitoes to land on and pick up spores to
induce mosquito infection and mortality. B. bassiana is known to kill infected mosquitoes within 6-8 days after contact
with spores. In one project, the spores’ nascent attractiveness or repellency first needed to be determined in order to
decide whether or they needed to be augmented with synthetic attractants to induce landing and infection. Unfed female
An. stephensi mosquitoes were tested one-at-a-time for their upwind flight propensity toward the arm of the Y-tube that
contained a 50 mg loading of spores, versus the other arm that contained a blank filter paper. The females clearly
exhibited a strong attraction towards B. bassiana spores; 75% of the females tested flew upwind to within 1 cm of the
spores, and a significant percentage of these actually landed on the spores themselves. A high percentage of the
mosquitoes (70%) was likewise attracted to 50 mg of the spores of M. acridum, and also to a lesser degree (65%) to 50 mg
of the spores of Aspergilus spp., a non-entomopathogenic species. The spores of Penicilium spp., on the other hand, were
deterrent to An. stephensi females, 80% of which preferred to fly up the blank arm of the Y-tube olfactometer and not to
the Penicilium spores. In competitive choice-tests between the spores of different fungal species, those of B. bassiana
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