FIG 1.

The strong impact of today's techniques for the analysis of our microbiota. The figure illustrates the different components of the microbes living inside, on, or around our body, whose identity can be achieved by using multiple complementary techniques. As shown, the first step is high-throughput DNA and cDNA/mRNA sequencing, which enables us to quantify alteration at the level of genes which can be directly related with the total (genomics) or with the expressed functionality (transcriptomics). The next logical step is assessing the proteome and the metabolome, the truly active components in the functional hierarchy. In more detail, the microbial genes encode proteins whose expression level can be studied by (proteomic) MS analysis. Finally, active proteins participate in biochemical reactions in which a number of substrates are converted into products. All of these metabolites can be studied by metabolomics.