Thermosipho

Abstract Ther.mo.si'pho. Gr. fem. n. thermê , heat; L. masc. n. sipho , little pipe to suck drinks through, a tube; N.L. masc. n. Thermosipho , the hot tube, due to the sheath surrounding the bacteria. Thermotogota / Thermotogae / Thermotogales / Fervidobacteriaceae / Thermosipho The genus Thermosipho is currently composed of eight species ( Thermosipho africanus , Thermosipho melanesiensis , Thermosipho japonicus , Thermosipho geolei , Thermosipho atlanticus , Thermosipho affectus , Thermosipho globiformans , and Thermosipho activus ). The rods are surrounded by an outer sheath‐like toga, and some rods form spheroids during growth. The spheroids may produce “immature progenies” that are too small to contain a complete genome, which need further investigation to elucidate their function. The cells are obligately anaerobic , thermophilic , with optimum growth temperature of 65–75°C, optimal pH 6.0–7.5, and optimal growth under low salinity 2.0–3.0% NaCl. Heterotrophic growth . Sulfur is reduced to H 2 S by all the species, while thiosulfate is reduced by Thermosipho africanus and Thermosipho japonicus . Molecular hydrogen inhibits growth. Two described Thermosipho spp. are capable of de novo biosynthesis of vitamin B12. Members of the phylum Thermotogota , class Thermotogae , order Thermotogales , and family Fervidobacteriaceae . Known habitats are shallow and deep‐sea hydrothermal vents and deep subsurface oil reservoirs. DNA G + C content (mol%) : 29.5–31.5 ( T m and genome analysis). Type species : Thermosipho africanus Huber et al. 1989, VL31 emend. Ravot et al. 1996.