Matching Items (2)
Filtering by

Clear all filters

136060-Thumbnail Image.png
Description
ABSTRACT Communication is vital in the context of everyday life for all organisms, but particularly so in social insects, such as Z. nevadensis. The overall lifestyle and need for altruistic acts of individuals within a colony depends primarily on intracolony chemical communication, with a focus on odorants. The perception of

ABSTRACT Communication is vital in the context of everyday life for all organisms, but particularly so in social insects, such as Z. nevadensis. The overall lifestyle and need for altruistic acts of individuals within a colony depends primarily on intracolony chemical communication, with a focus on odorants. The perception of these odorants is made possible by the chemoreceptive functions of sensilla basiconica and sensilla trichoid which exist on the antennal structure. The present study consists of both a morphological analysis and electrophysiological experiment concerning sensilla basiconica. It attempts to characterize the function of neurons present in sensilla basiconica through single sensillum recordings and contributes to existing literature by determining if a social insect, such as the dampwood termite, is able to perceive a wide spectrum of odorants despite having significantly fewer olfactory receptors than most other social insect species. Results indicated that sensilla basiconica presence significantly out-paced that of sensilla trichoid and sensilla chaetica combined, on all flagellomeres. Analysis demonstrated significant responses to all general odorants and several cuticular hydrocarbons. Combined with the knowledge of fewer olfactory receptors present in this species and their lifestyle, results may indicate a positive association between the the social complexity of an insect's lifestyle and the number of ORs the individuals within that colony possess.
ContributorsMcGlone, Taylor (Author) / Liebig, Juergen (Thesis director) / Ghaninia, Majid (Committee member) / Barrett, The Honors College (Contributor)
Created2015-05
183559-Thumbnail Image.png
Description

Enantiomers are pairs of non-superimposable mirror-image molecules. One molecule in the pair is the clockwise version (+) while the other is the counterclockwise version (-). Some pairs have divergent odor qualities, e.g. L-carvone (“spearmint”) vs. D-carvone (“caraway”), while other pairs do not. Existing theory about the origin of such differences

Enantiomers are pairs of non-superimposable mirror-image molecules. One molecule in the pair is the clockwise version (+) while the other is the counterclockwise version (-). Some pairs have divergent odor qualities, e.g. L-carvone (“spearmint”) vs. D-carvone (“caraway”), while other pairs do not. Existing theory about the origin of such differences is largely qualitative (Friedman and Miller, 1971; Bentley, 2006; Brookes et al., 2008). While quantitative models based on intrinsic molecular features predict some structure–odor relationships (Keller et al., 2017), they cannot identify, e.g. the more intense enantiomer in a pair; the mathematical operations underlying such features are invariant under symmetry (Shadmany et al., 2018). Only the olfactory receptor (OR) can break this symmetry because each molecule within an enantiomeric pair will have a different binding configuration with a receptor. However, features that predict odor divergence within a pair may be identifiable; for example, six-membered ring flexibility has been offered as a candidate (Brookes et al., 2008). To address this problem, we collected detection threshold data for >400 molecules (organized into enantiomeric pairs) from a variety of public data sources and academic literature. From each pair, we computed the within-pair divergence in odor detection threshold, as well as Mordred descriptors (molecular features derived from the structure of a molecule) and Morgan fingerprints (mathematical representations of molecule structure). While these molecular features are identical within-pair (due to symmetry), they remain distinct across pairs. The resulting structure+perception dataset was used to build a predictive model of odor detection threshold divergence. It predicted a modest fraction of variance in odor detection threshold divergence (r 2 ~ 0.3 in cross-validation). We speculate that most of the remaining variance could be explained by a better understanding of the ligand-receptor binding process.

ContributorsColeman, Liyah (Author) / Pavlic, Theodore (Thesis director) / Gerkin, Richard (Committee member) / Barrett, The Honors College (Contributor) / Computer Science - BS (Contributor)
Created2023-05