An NMR-based metabonomic investigation of the toxic effects of 3-trifluoromethyl-aniline on the earthworm Eisenia veneta

H-1 NMR spectra of earthworms Eisenia veneta treated with 3-trifluoromethyl -aniline in a 72-h contact filter paper test have been analysed using patte rn recognition techniques to determine the biochemical response. Various st rategies for data reduction of the metabolite profile, and illustration by principal components analysis are applied and discussed. The use of mean pr incipal components plots in simplifying group data representation and highl ighting the dose-response function is demonstrated. Hierarchical cluster an alysis, and cluster significance analysis of the principal components were also used to examine the relative distribution of dose groups. Identificati on and assignment of metabolite responses to toxicity were found via correl ation coefficient-shift plots. As measured by the correlation coefficients alanine was the most significant metabolite, but increased levels of other amino acids such as glycine and asparagine were also observed. Further, ele vated levels of glucose, and the citric acid cycle intermediates citrate an d succinate were noted as potential biomarkers of toxicity. This work provi des a basis for examining the biochemical response of invertebrates to toxi ns. This should provide a framework to examine toxicity effects of other ha logenated aromatic pollutants to earthworms used as environmental monitors.