Thioalkalicoccus limnaeus gen. nov., sp. nov., a new alkaliphilic purple sulfur bacterium with bacteriochlorophyll b.

Abstract

Four strains of purple sulfur bacteria containing bacteriochlorophyll b were isolated from cyanobacterial mats of soda lakes in the steppe of south-east Siberia, Russia. Cells of all strains were cocci without gas vesicles. Eventually, cells with flagella were seen in the electron microscope, but motile cells were observed very rarely in cultures. Internal photosynthetic membranes were of the tubular type. Photosynthetic pigments were bacteriochlorophyll b and carotenoids with spectral characteristics similar to 3,4,3',4'-tetrahydrospirilloxanthin. The bacteria were obligately phototrophic and strictly anaerobic. Hydrogen sulfide and elemental sulfur were used as photosynthetic electron donors. Thiosulfate was not used. During growth on sulfide, sulfur globules were formed as intermediate oxidation products, deposited inside the cells and centrally located. In the presence of sulfide and sodium bicarbonate, acetate, malate, propionate, pyruvate, succinate, fumarate and yeast extract were photoassimilated. Growth factors were not required. The new bacterium is an obligate alkaliphile growing at pH 8-10 with an optimum at pH 9. It showed good growth up to 60 % sodium chloride and up to 85 % sodium carbonates. Phenotypically, it is similar to Thiococcus pfennigii, but different by virtue of its alkaliphily and salt tolerance. The DNA GMC content was 636-648 mol %, compared to 694-699 mol % for Thiococcus pfennigii. The 16S rDNA sequence of strain A26T was approximately 92 % similar to that of Thiococcus pfennigii DSM 226 and therefore a new genus and species name, Thioalkalicoccus limnaeus gen. nov. and sp. nov., are proposed for the new bacterium.

Thioflavicoccus mobilis gen. nov., sp. nov., a novel purple sulfur bacterium with bacteriochlorophyll b.

“…3). The membrane system resembled that of Thiococcus pfennigii (Eimhjellen et al, 1967) and Thioalkalicoccus limnaeus (Bryantseva et al, 2000). Ultrathin sections also revealed an outer membrane and a cytoplasmic membrane characteristic of Gramnegative bacteria (Fig.…”

“…al., 1998). Only a few strains of the Chromatiaceae containing bacteriochlorophyll b have been isolated so far, such as the recently described bacteria from alkaline soda lakes in Siberia, which were described as Thioalkalicoccus limnaeus (Bryantseva et al, 2000).…”

Diversity of RuBisCO gene responsible for CO2 fixation in an Antarctic moss pillar

“…3). T. limnaeus is an alkalophilic bacterium isolated from Lake Natron in southeast Siberia, Russia with a pH range of 9.5-10.1 (Bryantseva et al 2000), which differs significantly from the 7-8-pH range of Lake Hotoke-Ike (Kimura et al 2010). Purple sulfur bacteria, of the order Chromatiales, generally engage in photoautotrophic metabolism using reduced inorganic sulfur compounds (e.g., hydrogen sulfide) as electron donors.…”

“…Thioalkalicoccus sp. contains bacteriochlorophyll b that functions intracellularly as a photosynthetic pigment (Bryantseva et al 2000). Thus, this group can only grow in limited areas in anaerobic environments that receive light and contain a stable supply of hydrogen sulfide.…”

Recommended standards for the description of new species of anoxygenic phototrophic bacteria

“…During the last few years, a fairly complete database of 16S rDNA sequences of available type strains (and additional other strains) of the species of Chlorobiaceae (Overmann & Tuschack, 1997;Alexander et al, 2002), purple sulfur bacteria (Imhoff & Süling, 1996;Guyoneaud et al, 1998;Imhoff et al, 1998), green filamentous bacteria (Keppen et al, 2000), 'Heliobacteriaceae' (Bryantseva et al, 1999(Bryantseva et al, , 2000Madigan, 2001) and purple non-sulfur bacteria (Hiraishi & Ueda, 1994;Hiraishi et al, 1995;Imhoff et al, 1998;Kawasaki et al, 1993) has been built up. These data have revealed the phylogenetic relationships of these bacteria based on 16S rDNA sequences and are used today to determine the phylogenetic position of novel isolates.…”