High resolution H-1 NMR spectroscopic studies of the composition of the haemolymph of crowd- and solitary-reared nymphs of the desert locust, Schistocerca gregaria

High resolution H-1 NMR spectroscopy provided a rapid and non-invasive mean s of establishing a multicomponent profile of the low molecular weight orga nic metabolites present in the haemolymph of crowd-reared and solitary-rear ed desert locusts. Assignments of the H-1 NMR resonances detected in the on e-dimensional (ID) spectra were supported by the comparison of chemical shi fts with those of commonly found metabolites, the application of 2D NMR spe ctroscopy, and spiking of authentic standards into the sample. The haemolym ph metabolite profile was found to comprise trehalose, a series of amino ac ids, organic acids, lipids. ethanol and the polyamine putrescine. In total, it was possible to detect simultaneously and potentially quantify over 20 endogenous compounds. An interesting difference between the phases was the higher putrescine concentrations present in solitary-reared nymphs. which m ay indicate a role of this compound in phase determination. In addition, di fferences in the concentrations of trehalose. lipids, acetate and ethanol w ere also observed between solitary-reared and gregarious-reared nymphs enab ling the ready differentiation of the two phases based on the NMR spectra o f the haemolymph. (C) 2001 Elsevier Science Ltd. All rights reserved.