Belliella buryatensis sp. nov., isolated from alkaline lake water.

Two bacterial isolates from water of the alkaline brackish Lake Solenoe (Buryatia, Russia), 2C and 5CT, were characterized by using a polyphasic taxonomic approach. The strains were small, non-motile, Gram-stain-negative rods that formed small orange-red colonies on the surface of marine agar. Studies based on 16S rRNA gene sequences showed that the strains were related closely to Belliella pelovolcani CC-SAL-25T (98.7 % sequence similarity). The G+C content of the DNA was 38-40 mol%. DNA-DNA hybridization values between strains 2C and 5CT and B. pelovolcani CC-SAL-25T were 56-58 mol%. A menaquinone with seven isoprene units (MK-7) was the major respiratory quinone. The fatty acid profiles were slightly different from that of B. pelovolcani CC-SAL-25T. The novel strains could be distinguished from the phylogenetically closest species B. pelovolcani CC-SAL-25T based on matrix-assisted laser desorption ionization time-of-flight mass spectra of whole cells and a range of physiological and biochemical characteristics. The data obtained suggest that strains 2C and 5CT represent a novel species of the genus Belliella, for which the name Belliella buryatensis sp. nov. is proposed. The type strain is 5CT ( = VKM B-2724T = KCTC 32194T).

Desulfonatronum zhilinae sp. nov., a novel haloalkaliphilic sulfate-reducing bacterium from soda Lake Alginskoe, Trans-Baikal Region, Russia.

A novel haloalkaliphilic sulfate-reducing bacterium, designated Al915-01(T), was isolated from benthic sediments of the Lake Alginskoe, a soda lake located in the Trans-Baikal Region, Russia. Cells of the strain were Gram-stain negative, motile, non-spore-forming vibrion (0.4-0.5 × 1.2-2.3 µm). Strain Al915-01(T) grew in the pH range from 8.0 to 10.5 (optimum pH 9.0) and required NaCl for growth (5-100 g l(-1) NaCl, optimum 40 g l(-1)). The bacterium grew at 10-40 °C (optimally at 36 °C) and used lactate, formate and pyruvate as electron donors in the presence of sulfate. It was able to reduce sulfate, sulfite, thiosulfate and nitrate with lactate as an electron donor. The isolate was able to grow lithoheterotrophically with sulfate and molecular hydrogen if acetate was added as a carbon source. The predominant fatty acids were anteisoC15:0, isoC17:1, C18:1ω7 and C16:1ω7. The G+C content in the DNA was 58.3 ± 1 mol %. Analysis of the 16S rRNA gene sequence showed that the new bacterium belongs to the genus Desulfonatronum. The closest relatives were Desulfonatronum buryatense Ki5(T) (99.9 % similarity) and Desulfonatronum lacustre Z-7951(T) (99.2 % similarity). On the basis of the genotypic, phenotypic and phylogenetic characteristics, the isolate is proposed as a representative of a novel species Desulfonatronum zhilinae with the type strain Al915-01(T) (=VKM B-2744(T) = DSM 26338(T)).

High abundances of aerobic anoxygenic phototrophs in saline steppe lakes.

We studied the distribution of anoxygenic phototrophs in 23 steppe lakes in the Transbaikal region (Russia), in Uzbekistan (Central Asia) and in the Crimean peninsula (Ukraine). The lakes varied in their mineral content and composition (salinities from 0.2 to 300 g L(-1) ). The Transbaikal lakes were alkaline (pH>9), with high amounts of soda. The Uzbek and Crimean lakes were more pH neutral, frequently with high amounts of sulfates. The presence of anoxygenic phototrophs was registered by infrared epifluorescence microscopy, infrared fluorometry and pigment analyses. In mostly shallow, fully oxic lakes, the anoxygenic phototrophs represented 7-65% of the total prokaryotes, with the maxima observed in Transbaikal soda lakes Gorbunka (32%), Khilganta (65%), Zanday (58%) and Zun-Kholvo (46%). Some of the lakes contained over 1 µg bacteriochlorophyll L(-1) . In contrast, only small amounts of anoxygenic phototrophs were present in highly mineralized lakes (>100 g total salts L(-1) ); Borzinskoe, Tsagan-Nur (Transbaikal), Staroe (Crimea) and in the residual part of the south-west Aral Sea (Uzbekistan). The oxic environment and the specific diurnal changes of bacteriochlorophyll concentration observed suggest that the phototrophic community was mostly composed of aerobic anoxygenic phototrophs. The high abundances and bacteriochlorophyll concentrations point to an important role of aerobic anoxygenic phototrophs in the habitats studied.

Moderately thermophilic nitrifying bacteria from a hot spring of the Baikal rift zone.

Samples from three hot springs (Alla, Seya and Garga) located in the northeastern part of Baikal rift zone (Buryat Republic, Russia) were screened for the presence of thermophilic nitrifying bacteria. Enrichment cultures were obtained solely from the Garga spring characterized by slightly alkaline water (pH 7.9) and an outlet temperature of 75 degrees C. The enrichment cultures of the ammonia- and nitrite oxidizers grew at temperature ranges of 27-55 and 40-60 degrees C, respectively. The temperature optimum was approximately 50 degrees C for both groups and thus they can be designated as moderate thermophiles. Ammonia oxidizers were identified with classical and immunological techniques. Representatives of the genus Nitrosomonas and Nitrosospira-like bacteria with characteristic vibroid morphology were detected. The latter were characterized by an enlarged periplasmic space, which has not been previously observed in ammonia oxidizers. Electron microscopy, denaturing gradient gel electrophoresis analyses and partial 16S rRNA gene sequencing provided evidence that the nitrite oxidizers were members of the genus Nitrospira.