Differentiation of the genus Thioflavicoccus from other genera

According to the results of 16S rDNA sequence analyses (Fig. BXII.y.3 of the chapter describing the family Chromatiaceae), the genus Thioflavicoccus belongs to the branch of the family Chro-matiaceae that characteristically contains marine and halophilic species. Characteristics for differentiation from other photo-trophic members of the family Chromatiaceae are shown in Table BXII.y.5 of the chapter describing the family Chromatiaceae. Thioflavicoccus mobilis is one of the very few species (in addition to Thiococcus pfennigii and Thioalkalicoccus limnaeus) that contain tubular internal photosynthetic membranes. The phylogenetic relationship of the Thioflavicoccus species to other Chromatiaceae species, based on 16S rDNA sequence comparison, is shown in Fig. BXII.y.3 of the chapter describing the family Chromatiaceae.

List of species of the

1. Thioflavicoccus mobilis Imhoff and Pfennig 2001, 109VP mo'bi.lis. L. adj. mobilis mobile.

Cells are coccoid, short, rod-shaped to diplococcus-shaped before cell division. Cocci 0.8-1.0 |im in diameter. Motile by monopolar monotrichous flagella. Internal photosynthetic membrane system of tubular type. Color of cell suspensions is yellowish beige to orange-brown. The absorption spectrum of living cell suspensions exhibits maxima at 410, 462, 492, 530, and 1025 nm, with shoulders at 602 and 835 nm. Photosynthetic pigments are bacterio-

genus Thioflavicoccus chlorophyll b and 3,4,3',4'-tetrahydro-spirilloxanthin as the main carotenoid. The metabolism is obligately photo-trophic and strictly anaerobic. Photolithoautotrophic growth occurs in the light with hydrogen sulfide as electron donor. Globules of elemental sulfur are accumulated inside the cells. The final oxidation product is sulfate. Thiosulfate is not used. In the presence of sulfide and bicarbonate, acetate, pyruvate, and ascorbate are used as organic substrates. Growth factors are not required. Sodium chloride is required for growth. Good growth occurs at 25-30°C, pH

7.2-7.4, with 1-3% NaCl (optimum is at 2%), and at 500 lux light intensity from a tungsten lamp. Habitat: laminated microbial mats of salt marshes.

Type strain: 8321, ATCC 700959.

GenBank accession number (16S rRNA) : AJ010126.

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