title: Swarm formation in the desert locust Schistocerca gregaria: isolation and NMR analysis of the primary maternal gregarizing agent.
abstract: Depending on their rearing density, female desert locusts Schistocerca gregaria epigenetically endow their offspring with differing phenotypes. To identify the chemical basis for such maternal transmission, we compared solitarious and gregarious locust egg pod foam using high performance liquid chromatography (HPLC). We revealed causal relationships between foam chemistry and hatchling phenotype (phase state) by iteratively applying HPLC fractions from gregarious locust egg foam extracts to solitarious eggs and assessing resulting hatchlings with a behavioural bioassay involving logistic regression. Selection and application of increasingly specific HPLC fractions allowed us to isolate compounds with gregarizing properties. Hatchling gregarization was triggered only by certain fractions and was dose dependent. In a final series of experiments, we characterized the most specific gregarizing fraction by nuclear magnetic resonance (NMR) spectroscopy. Here we present tentative structural features of the primary locust maternal gregarizing agent, which appears to be an alkylated l-dopa analogue. In addition, we propose a mechanism for phase-dependent regulation of this compound's activity.
authors.affiliation: School of Biological Sciences, The University of Sydney, Heydon-Laurence Building A08, NSW 2006, Australia.
authors.forename: Gabriel A
authors.initials: GA
authors.lastname: Miller
authors.forename: M Saiful
authors.initials: MS
authors.lastname: Islam
authors.forename: Timothy D W
authors.initials: TD
authors.lastname: Claridge
authors.forename: Tim
authors.initials: T
authors.lastname: Dodgson
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Simpson
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D001685:Biological Factors / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification*; D002851:Chromatography, High Pressure Liquid; D003889:Desert Climate; D005260:Female; D006110:Grasshoppers / Q000502:physiology*; D016015:Logistic Models; D009682:Magnetic Resonance Spectroscopy; D010063:Ovum; D012995:Solubility; D012997:Solvents
chemical_list: D001685:Biological Factors; D012997:Solvents