Metabolic overview of conserved pathways in E. coli , P. atrosepticum and D. dadantii. Changes in gene expression under anaerobic conditions are shown for all three organisms and are represented by different colors. Fold change patterns and genome order are as follows: E. coli, P. atrosepticum and D. dadantii (see key within the figure). Each orthologous group of genes is represented by three blocks colored by fold change (dark blue: down-regulated, fold change > 3; light blue: down-regulated, fold change < 3; bright yellow: up-regulated, fold change > 3; dirty yellow: up-regulated, fold change < 3; black: no change in expression, X: ortholog absent in that organism). Fold change values for poly-cistronic operons are averaged across genes. The transcriptional regulators FNR, ArcA, NarP, NarL and FhlA, for which there are known targets, are denoted in the figure based on their mode of regulation: (▲) up regulated (▼) down-regulated. Several components in this figure, such as fermentation and respiratory chains are adapted from Unden and Dunnwald and Sawers et al. 2004 [34, 46]. A more detailed diagram of the genomic structure for formate hydrogen lyase complex and accompanying hydrogenases (HYD 1-4) is shown in Figure 3.