Diversity of Prokaryotes in Planktonic Communities of Saline Sol-Iletsk lakes (Orenburg Oblast,Russia)

Prokaryotic diversity was studied in the planktonic communities of six Sol-Iletsk lakes (Orenburg oblast, Russia) varying in salinity level using the Illumina technology of high-throughput sequencing. The extremely halophilic archaea of the phyla Euryarchaeota and Nanohaloarchaeota, as well as the bacterial phylum Bacteroidetes predominated in the communities of lakes with salinity of 285–300‰. Representatives of the phyla Bacteroidetes and Actinobacteria, as well as of the class Gammaproteobacteria were predominant in the lakes with salinity 110?180‰. A bloom of Cyanobacteria was observed in Bol’shoe Gorodskoe Lake (10‰ salinity). The dominant OTUs in the lakes with high salinity were represented by archaea Halonotius sp., uncultured Nanohaloarchaea, and bacteria Salinibacter sp. In the lakes with medium salinity level the dominants included gammaproteobacteria Spiribacter sp., alphaproteobacteria Roseovarius sp., flavobacteria Psychroflexus sp., unidentified archaea of the family Haloferacaceae, actinobacteria Pontimonas sp. and Rhodoluna sp. In the lake with low salinity level cyanobacteria of the genus Planktothrix were predominant. Effect of salinity on prokaryotic taxonomic richness, composition, and diversity in planktonic communities of the studied lakes was demonstrated.     

Multiple Euryhaline Lineages of Centrohelids (Haptista: Centroplasthelida) in Inland Saline Waters Revealed with Metabarcoding

The diversity of centrohelids in inland saline waters was studied with metabarcoding for the first time. The fragment of V6–V7 regions of 18S rDNA was sequenced with newly designed primers. Obtained OTUs were identified with molecular phylogenetic analysis and comparison of the signatures in 39es9 hairpin of V7. The obtained data included some OTUs, which could be attributed to four described species, but the majority belonged to previously established or novel environmental clades. Along with some presumably marine/brackish clades and freshwater/low salinity (0–2 ppt) clades, seven presumable species demonstrating broad (from 1–2 up to 78 ppt) salinity tolerance were detected. A number of OTUs belonged to Raphidocystis contractilis, which is known from three independent findings in brackish habitats only. Thus, it was assumed that this species is stenohaline and specifically adapted to salinity 5–15 ppt. The high level of salinity tolerance was suggested for centrohelids before based on morphology, which was used to justify their cosmopolitan distribution. Later these views were criticized based on environmental sequencing, but the results of the current survey indicate, that at least some species are present at salinities from almost freshwater (1–2 ppt) to twice oceanic (78 ppt) and are presumably capable of overcoming oceanic salinity barriers for their distribution.     

Determination with a microelectrode of membrane potential of giant human erythrocytes obtained by La(3+)-induced fusion

The effect of La3+ on the fusion of erythrocytes of blood stored for a week at +4 degrees C was studied. It was shown that the fusion of erythrocytes begins after one day of storage of blood. The most intensive fusion of erythrocytes was observed on day 4 of blood storage. As a result, giant cells with a size of 100 microns and more arise. The electrical potential of giant cells was measured using a microelectrode and was -6.6 +/- 1.5 mV.     

Microbial processes of organic matter production and decomposition in saline rivers of the Lake Elton area (Volgograd oblast,Russia)

The rates of microbial processes and phylogenetic diversity of the microorganisms responsible for organic matter production and decomposition in the benthic communities and bottom sediments of the rivers Solyanka, Lantsug, Khara, Chernavka, and Bol’shaya Smorogda (Lake Elton area, Volgograd oblast, Russia) were studied. The biomass and primary production of cyano–bacterial communities varied significantly within the ranges of 20–903 mg Chl a/m² and 0.2–21 mg C/(m² h), respectively. Depending on the season, the share of anoxygenic CO₂ fixation varied from 20% to the values comparable to the rate of oxygenic photosynthesis. The total heterotrophic activity of microbial communities determined as the rate of dark CO₂ assimilation varied from 31 to 750 μmol/(dm³ day) in the mats and from 3 to 137 μmol/(dm³ day) in the sediments. The rates of sulfate reduction and hydrogenotrophic methanogenesis varied from 10 to 2621 μmol S/dm³ day) and from 1.5 to 323 nmol CH₄/(dm³ day), respectively. High-throughput sequencing of the 16S rRNA genes in cyano–bacterial mats revealed microorganisms belonging to 20 phyla, with the sequences of Cyanobacteria, Proteobacteria, and Bacteroidetes being the most numerous.     

Bacterial Diversity in Attached Communities of a Cold High-Sulfide Water Body in European Russia

Microbiology - Bacterial diversity in attached communities of the anoxic part of the Solodovka wetland (Samara region, Russia), which feeds on cold karst springs with a high (>3 mM) sulfide...