Taxonomic Comments

Isochromatium buderi was previously known as Chromatium buderi (Truuper and Jannasch, 1968). It was transferred to the new genus Isochromatium based on significant genetic and physiological differences from Chromatium species and other members of the Chromatiaceae (Imhoff et al., 1998b). Isochromatium buderi belongs to the branch of truly marine and halophilic Chromatiaceae species.

List of species of the

1. Isochromatium buderi (TrUper and Jannasch 1968) Imhoff, Suling and Petri 1998b, 1141VP (Chromatium buderi TrUper and Jannasch 1968, 364.)

bu' der.i. M.L. gen. n. buderi of Buder; named for J. Buder, a German plant physiologist.

Cells ovoid to rod shaped, 3.5-4.5 X 4.5-9 | m during exponential growth, about 3-4 | m in the stationary phase, motile by a polar tuft of flagella which is usually 1.5-2 times the cell length and may be visible in the light microscope. Globules of S0 appear evenly distributed within the cell. Color of individual cells grayish, color of cell suspensions pinkish violet to purple-violet. Photosynthetic pigments are bacteriochlorophyll a and carotenoids of the rhodopinal group.

Obligately phototrophic and strictly anaerobic. Sulfide and S0 used as electron donors for photolithoautotrophic genus Isochromatium growth. In the presence of sulfide and bicarbonate, acetate and pyruvate are photoassimilated. Not utilized: thiosulfate, molecular hydrogen, sugars, alcohols, higher fatty acids, amino acids, benzoate, formate, and most intermediates of the tricarboxylic acid cycle. Assimilatory sulfate reduction is absent. Nitrogen sources: ammonium salts. Vitamin B12 required.

Mesophilic marine bacterium requiring NaCl for growth. Optimum growth at 1-3% (w/v) NaCl, otherwise extremely pleomorphic, pH optimum for growth 7.2-7.4 (range 6.57.6), and temperature growth optimum 25-35°C.

Habitat: estuarine salt flats and salt marshes.

The mol% G + C of the DNA is: 62.2-62.8 (Bd), type strain: 62.2 (Bd).

Type strain: 8111, ATCC 25588, DSM 176.

GenBank accession number (16S rRNA): AJ224430.

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