Exometabolomic mapping of Caenorhabditis elegans: a tool to noninvasively investigate aging

Metabolomic analyses can provide valuable information about the internal metabolism of an organism; however, these studies can become quickly complicated by the large number of metabolites that are often detected. Overcoming this limitation requires high-resolution analytical separation techniques, coupled with high-power deconvolution software. Additionally, much care must be taken in metabolomic sample preparation to quench active enzymes and avoid artifactual changes in the metabolome. Here we present a relatively simple and straightforward technique, exometabolome mapping, which bypasses each of these concerns, is noninvasive, and provides a concise summary of the key metabolic processes operative in an organism. We illustrate our method using the nematode C. elegans, an organism which has been widely exploited in aging studies; however, with only minimal modification, our technique is extendible to other sample types, and indeed we have successfully used it both to perform yeast footprinting and to study the excreted metabolic end products of human kidney cancer cell lines.