Figure 3.

Acidithiobacillus thiooxidans Licanantay bioleaching co-regulatory network. Transcriptional factors in the co-regulatory network are depicted as rectangular (dark gray) and oval nodes (light gray). Rectangular nodes correspond to primary regulators while oval nodes are transcriptional factors member of chain regulatory cascades. Leaf nodes are target operons colored according to their metabolic bioleaching sub-categories. Solid arcs represent regulation between transcriptional factors and dotted arcs represent regulation of metabolic operons. Hierarchical levels are listed at the bottom of the figure. Red circle highlights CysB transcription factor. Colored arcs (red, green, and light blue) correspond to connections forming directed cycles in the network. There are three directed cycles: a small one between FLIA and IHF (green arcs) and two larger ones that share the path made by light-blue arcs. Thus, removing any green and light blue pair of arcs breaks all directed cycles (minimum feedback arc sets).