title: Cuticular hydrocarbon analysis of an awake behaving fly using direct analysis in real-time time-of-flight mass spectrometry.
abstract: In mammals and insects, pheromones strongly influence social behaviors such as aggression and mate recognition. In Drosophila melanogaster, pheromones in the form of cuticular hydrocarbons play prominent roles in courtship. GC/MS is the primary analytical tool currently used to study Drosophila cuticular hydrocarbons. Although GC/MS is highly reproducible and sensitive, it requires that the fly be placed in a lethal solution of organic solvent, thereby impeding further behavioral studies. We present a technique for the analysis of hydrocarbons and other surface molecules from live animals by using direct analysis in real-time (DART) MS. Cuticular hydrocarbons were sampled from the surface of a restrained, awake behaving fly by using several brief, carefully controlled depressions of the abdomen with a small steel probe. DART mass spectral analysis of the probe detected ions with mass-to-charge ratio (m/z) of the protonated molecule corresponding to many of the previously identified unsaturated hydrocarbons. Six additional cuticular hydrocarbons also were identified. Consistent with previous GC/MS studies, male and female differences in chemical composition were evident. Spatial differences in the expression profile also were observed on males. Sampling from an individual female first as a virgin and then 45 and 90 min after successful copulation showed that mass signals likely to correspond to cis-vaccenyl acetate, tricosene, and pentacosene increased in relative intensity after courtship. This method provides near-instantaneous analysis of an individual animal's chemical profile in parallel with behavioral studies and could be extended to other models of pheromone-mediated behavior.
authors.affiliation: Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA.
authors.forename: Joanne Y
authors.initials: JY
authors.lastname: Yew
authors.forename: Robert B
authors.initials: RB
authors.lastname: Cody
authors.forename: Edward A
authors.initials: EA
authors.lastname: Kravitz
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D004331:Drosophila melanogaster; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D006838:Hydrocarbons / Q000737:chemistry*; D007477:Ions; D008297:Male; D013058:Mass Spectrometry / Q000379:methods*; D010675:Pheromones / Q000378:metabolism; D012724:Sex Attractants; D012726:Sexual Behavior, Animal; D012997:Solvents / Q000737:chemistry; D013997:Time Factors; D014851:Wakefulness
chemical_list: D006838:Hydrocarbons; D007477:Ions; D010675:Pheromones; D012724:Sex Attractants; D012997:Solvents