Fig. 5. Cell metabolic cartoon constructed from the genome annotation of “Ca. N. alkalitolerans”.

Features putatively involved in the adaptation to high alkalinity and salinity, and selected core metabolic pathways of chemolithoautotrophic nitrite-oxidizing Nitrospira, are shown. Note that the transport stoichiometry of the ion transporters in “Ca. N. alkalitolerans” remains unknown. Colors of text labels indicate whether adaptive features are present (i.e., have homologs) in the genomes of other NOB (red, feature is not present in any other characterized NOB; blue, feature is present only in the marine Nitrospina gracilis; purple, feature is present in several other characterized NOB).