Table 1.

Comparative characteristics of the species belonging to the genus Nitrospira sublineages I and II

	Nitrospira japonica (in this study)	“Ca. Nitrospira defluvii”	Nitrospira moscoviensis
Phylogenetic affiliation in genus Nitrospira	Sublineage II	Sublineage I	Sublineage II
Cell morphology	Short, curved rods cells	Short, slightly curved cells or spiral-shaped rods	Irregularly shaped cells or spiral-shaped rods
Size (μm)	0.3–0.5×0.5–0.7	0.2–0.4×0.7–1.7	0.2–0.4×0.9–2.2
Tendency to aggregate	Strong	Strong	Present
Optimum growth temperature (°C)	31	28–32	39
Utilization of organic substrate	Growth with formate	Assimilate pyruvate, and pyruvate stimulated growth of Nitrospira	Not observed