Complete genome sequence of the termite hindgut bacterium Spirochaeta coccoides type strain (SPN1T), reclassification in the genus Sphaerochaeta as Sphaerochaeta coccoides comb. nov. and emendations of the family Spirochaetaceae and the genus Sphaerochaeta

Table 7. Typical features of reference taxa.

	Spirochaeta coccoides [1]	Genus Sphaerochaeta [4]	Genus Spirochaeta [30]
Cell shape	coccoid, spherical, not spiral	coccoid, spherical, pleomorphic; not helical or spiral	helical or spiral; spherical bodies under unfavorable growth conditions
Cell size	0.5–2.0 µm	0.4–2.5 µm	0.2–0.75 by 5–250 µm
Motility	non-motile	non-motile	motile
Flagellation	no flagella	no flagella	2 periplasmic flagella (exception: S. plicatilis, with many flagella)
T-optimum	30 °C	mesophilic	25–68 °C
pH-optimum	7.4	neutrophilic
Oxygen requirement	anaerobe	anaerobe	obligately anaerobe or facultatively anaerobe
Fermentation products	acetate, ethanol, formate	acetate, ethanol, formate	acetate, ethanol, CO₂, H₂
G+C content	56.6–57.4 mol% [1] 51 mol%, this study	45–48 mol%	51–65 mol% [30] 44–65 mol% [29]

On the basis of the above mentioned physiological and phylogenetic characteristics of strain SPN1^T, its reclassification into the genus Sphaerochaeta is proposed. The inclusion of Sphaerochaeta in Spirochaetaceae also makes an emendation of the family necessary, as its previous description excludes features specifically found in Sphaerochaeta.

ISSN: 2524-6372