Differentiation of the genus Lamprobacter from

other genera

The genus Lamprobacter is characterized and distinguished from other members of the family Chromatiaceae by rod-shaped motile cells that develop gas vesicles under certain growth conditions. Characteristics used for differentiation of the genus Lamprobacter from other members of the Chromatiaceae are shown in Table BXII.y.6 of the chapter describing the family Chromatiaceae.

List of species of the genus Lamprobacter

1. Lamprobacter modestohalophilus Gorlenko, Krasil'nikova, Kikina and Tatarinova 1988, 220VP (Effective publication: Gorlenko, Krasil' nikova, Kikina and Tatarinova 1979, 765.) mo.des'to.ha.lo'phi.lus. L. n. modestus moderate; Gr. n. hals salt; Gr. adj. philos loving; M.L. masc. adj. modestohalophilus moderate salt-loving.

Cells are rod shaped or ovoid, 2.0-2.5 X 4-5 |im, polymorphic under changing conditions of incubation (Fig. BXII.y.8). Life cycle with two alternating morphological forms: nonmotile cells with gas vesicles and slime capsules, and cells motile by means of flagella and devoid of gas vesicles. Gas vesicles frequently located in the cell periphery, globules of S0 in center of cells. Photosynthetic membranes of the vesicular type. Vesicles in cells grown in mineral medium measure about 70 nm in diameter. Photosynthetic pigments are bacteriochlorophyll a and carotenoids of the okenone group.

Growth under anoxic conditions in the light and under microoxic conditions in the dark. Under anoxic conditions in the light, cell suspensions appear purple to pink. Under aerobic conditions in the dark, synthesis of pigments is reduced and cultures become colorless. Photosynthetic electron donors used are sulfide, thiosulfate, S0, and hydrogen, but not sulfite. Electron donors in the dark are thiosulfate and sulfur. Sulfide and thiosulfate are oxidized to S0 and sulfate. Assimilatory sulfate reduction is absent and reduced sulfur compounds are required.

CO2 assimilated via the Calvin cycle. In the presence of sulfide (or thiosulfate) and bicarbonate, alcohols (glycerol, n-propanol, n-butanol, ethanol, isobutanol, and isopropa-nol), and organic acids (lactate, pyruvate, and acetate) are photoassimilated. Methanol, isoamyl alcohol, sorbitol, dul-citol, mannitol, succinate, fumarate, malate, lactose, maltose, xylose, galactose, and fructose are not utilized. Growth inhibited by n-amyl alcohol, allyl alcohol, formate, propi-onate, benzoate, arabinose, rhamnose, and raffinose. Ni-

trogen sources used. ammonium salts, urea, casein hydro-lysate, glutamic acid, and N2. Hydrogenase and catalase activity occur. Storage materials: S0, poly-b-hydroxybutyrate, polyphosphate, and polysaccharide. Vitamin B12 required.

Optimum growth is at 23-27°C, pH 7.4-7.6, 1-4% NaCl (up to 9% NaCl). Sodium chloride is required for growth. Favorable light intensity is 3000 lux.

Habitat: hydrogen sulfide-containing mud and water of saline water bodies with 1-11% salinity.

Type strain: Type strain INMI RO-1 is lost; no neotype strain designated.

Additional Remarks: Available candidate for neotype: "Sy-vash" (Institute of Microbiology, Russia Academy of Sciences, Moscow, Russia), isolated from a lagoon of salt lake Syvash (Crimea) with 6.7% salinity, pH range for growth 6.9-7.6, temperature range for growth from 20 to 30°C.

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