Taxonomic Comments

In addition to Thiospirillum jenense, two other species of Thiospirillum, "Thiospirillum sanguMneum" and "Thiospirillum rosenbergii", have been described from observations of water and mud samples collected in nature. The former species was described as having the same size and morphology as Thiospirillum jenense, with which it could have been confused. More recent reports of the existence of "Thiospirillum rosenbergii" are lacking. Winogradsky (1888) originally designated Thiospirillum sanguineum as the type species of this genus. However, because this species, in contrast to Thiospirillum jenense, has never been obtained in pure culture, Thiospirillum jenense was later recognized as the type species (Pfennig, 1989d). Further studies of strains obtained in pure culture and 16S rDNA sequence analyses are required to determine the re-latedness of Thiospirillum species with each other and with other members of the family Chromatiaceae. According to 16S rRNA oligonucleotide catalogs, Thiospirillum jenense is not similar to Chromatium and Allochromatium species (Fowler et al., 1984), though it may be distantly related to these bacteria and belong to the corresponding group of motile freshwater Chromatiaceae species.

List of species of the genus Thiospirillum

1. Thiospirillum jenense (Ehrenberg 1838) Migula 1900, 1050al ( Ophidomonas jenensis Ehrenberg 1838, 44.) je.nen' se. M.L. neut. adj. jenense jenense pertaining to Jena, Germany, the city where Ehrenberg discovered this organism.

Cells curved rods, sigmoid or spiral-shaped, 2.5-4.0 |im wide. Sigmoid cells usually 30-40 |m long, spiral cells up to 100 |m long. Complete turns may measure 15-40 |m and have a coil depth of 3-7 |m. Motile by a polar tuft of flagella, which is usually 10-12 |m long and visible by brightfield or phase-contrast microscopy (Fig. BXII.y.18). Cells rarely tufted at both ends. Color of individual cells is pale yellow, color of cell suspensions yellowish to orange-brown. Photosynthetic pigments are bacteriochlorophyll a and the carotenoids lycopene and rhodopin (Schmidt et al., 1965).

Obligately phototrophic and strictly anaerobic. Photo-lithoautotrophic growth with sulfide and S0 as electron donors. Thiosulfate not utilized. In the presence of sulfide and bicarbonate, acetate is photoassimilated. Nitrogen sources: ammonium salts. Vitamin B12 required for growth.

Mesophilic freshwater bacterium with optimum growth at 20-25°C and pH 7.0 (range 6.5-7.5).

Habitat: mud and stagnant water of ditches and freshwater ponds containing hydrogen sulfide.

Type strain: 1112, DSM 216.

FIGURE BXII.y.18. Thiospirillum jenense DSM 216 cultured photoauto-trophically with sulfide. Note the intracellular sulfur globules and the short, slightly sigmoidal tufts of polar flagella. Brightfield micrograph. Bar = 10 im.
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