TABLE 2.

Unique genes and putative functional biases in the genus Nitrobacter

Organism	Category (functions)
N. winogradskyi Nb-255	Transport (NO3−/sulfonate/CO32− [2], iron uptake systems, nickel/cobalt, PO43− porin, uncharacterized ABC transporter components), miscellaneous (histidine biosynthesis, multiple FecIR genes, pyrroloquinoline quinone biosynthesis)
N. hamburgensis X14	Transport (ammonia permease, K+ transport, uncharacterized ABC transport components), carbon metabolism (formate dehydrogenase, carbon monoxide dehydrogenase-like, l-lactate dehydrogenase, malate dehydrogenase, pyruvate-formate lyase, homogentisate/phenylacetate degradation), energetics (cytochrome c oxidase, cytochrome bd ubiquinol oxidase, cytochome b561 [4], cytochrome P460, flavoredoxin reductase, sulfur oxidation genes [soxXYZAB], nitric oxide reductase [sNOR]), miscellaneous (type II secretion, serine proteases, conjugal transfer, heavy metal resistance, arsenite oxidase)
Nitrobacter sp. strain Nb-311A	Transport (TonB systems, Ca2+/Na2+ antiporter, Cl− channel, chromate, uncharacterized ABC transporter components, Mg/cobalt, sulfate permeases, Co/Zn/Cd efflux), replication (DNA replication/repair, DNA polymerases IV and III, minCDE septum formation), miscellaneous (polysaccharide synthesis and export, UspA stress genes, ectoine synthase, cation ATPases, pyoverdine synthesis, hydroxymate siderophore syn. [IucC family])