(-)-Menthone

16958095

As part of our ongoing effort to relate stimulus to response in the olfactory system, we tested the hypothesis that the unique chemical structures and odors of various cyclic odorants would be associated with unique spatial response patterns in the glomerular layer of the rat olfactory bulb. To this end, rats were exposed to sets of odorants including monocyclic hydrocarbons, bicyclic compounds, and various heterocyclic structures containing oxygen or nitrogen in the ring. Relative activity across the entire layer was assessed by mapping uptake of 2-deoxyglucose into anatomically standardized data matrices. Whereas monocyclic hydrocarbons evoked patterns similar to those evoked by open-chained hydrocarbon odorants, a set of bicyclic compounds with structures and odors similar to camphor evoked uptake in paired ventral domains not previously associated with any other odorant chemical structures. Despite their unique odors as judged by humans, heterocyclic odorants either evoked uptake in previously characterized areas corresponding to their functional groups or stimulated weak or patchy patterns involving isolated glomeruli. While the patchiness of the patterns may be partly related to the rigidity of the compounds, which would be expected to restrict their interactions to only a few receptors, the weakness of the patterns suggests the possibility of species-specific odorant representations. We conclude that whereas some of the novel cyclic structures indeed were represented by unique patterns in the rat bulb, other unique structures were poorly represented, even when they evoked intense and unique odors in humans.

Differential specificity in the glomerular response profiles for alicyclic, bicyclic and heterocyclic odorants

Brett A. Johnson,1,* Zhe Xu,1 Paige Pancoast,1 Jennifer Kwok,1 Joan Ong,1 and Michael Leon1

2008 Jan 27.

32685798

Nowadays, crop protection is a major concern and how to proceed is a delicate point of contention. New products must be safe and ecofriendly in accordance with the actual legislation. In this context, we present a quantitative structure-activity relationship strategy based on molecular topology as a tool for generating natural products as potential fungicides following a mechanism of action based on the synthesis of chitin inhibition (chitinase inhibition). Two discriminant equations using statistical linear discriminant analysis were used to identify three potential candidates (1-methylxanthine, hematommic acid, and antheraxanthin). The equations showed accuracy and specificity levels above 80%, minimizing the risk of selecting false active compounds.

Molecular Topology QSAR Strategy for Crop Protection: New Natural Fungicides with Chitin Inhibitory Activity

Maria Galvez-Llompart,†§ Riccardo Zanni,‡§ Jorge Galvez,§ and Ramon Garcia-Domenechcorresponding author*§

2020 Jul 14