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Autotrophic picoplankton of Lake Baikal was studied during 30 years. New species of algae, including endemic organisms, were found there. It has been found that autotrophic picoplankton is the main chain of the trophic link of the lake. It is highly diverse in its species composition. Its maximum numbers are observed in winter. The numbers of autotrophic picoplankton inversely depend on the numbers of large phytoplankton. Mass development of phytoplankton in summertime registered after the period of spring water bloom formed by its large forms is responsible for the optimal functioning of the biota of Lake Baikal, and also for the formation of primary organic matter in the pelagic zone of the Lake throughout the year. [ABSTRACT FROM AUTHOR]

In this study, we analyzed the transcriptomes of RNA and DNA viruses from the oligotrophic water of Lake Baikal and the effluent from wastewater treatment plants (WWTPs) discharged into the lake from the towns of Severobaikalsk and Slyudyanka located on the lake shores. Given the uniqueness and importance of Lake Baikal, the issues of biodiversity conservation and the monitoring of potential virological hazards to hydrobionts and humans are important. Wastewater treatment plants discharge treated effluent directly into the lake. In this context, the identification and monitoring of allochthonous microorganisms entering the lake play an important role. Using high-throughput sequencing methods, we found that dsDNA-containing viruses of the class Caudoviricetes were the most abundant in all samples, while Leviviricetes (ssRNA(+) viruses) dominated the treated water samples. RNA viruses of the families Nodaviridae , Tombusviridae , Dicitroviridae , Picobirnaviridae , Botourmiaviridae , Marnaviridae , Solemoviridae , and Endornavirida were found in the pelagic zone of three lake basins. Complete or nearly complete genomes of RNA viruses belonging to such families as Dicistroviridae , Marnaviridae , Blumeviridae , Virgaviridae , Solspiviridae , Nodaviridae , and Fiersviridae and the unassigned genus Chimpavirus, as well as unclassified picorna-like viruses, were identified. In general, the data of sanitary/microbiological and genetic analyses showed that WWTPs inadequately purify the discharged water, but, at the same time, we did not observe viruses pathogenic to humans in the pelagic zone of the lake.

The proliferation of benthic cyanobacteria has been observed in Lake Baikal since 2011 and is a vivid manifestation of the ecological crisis occurring in the littoral zone. The cyanobacterium Symplocastrum sp. has formed massive fouling on all types of benthic substrates, including endemic Baikal sponges. The strain BBK-W-15 (=IPPAS B-2062 T ), which was isolated from sponge fouling in 2015, was used for further taxonomic determination. A polyphasic approach revealed that it is a cryptic taxon of cyanobacteria. Morphological evaluation of the strain indicated the presence of cylindrical filaments with isodiametric cells enclosed in individual sheaths and coleodesmoid false branching. Strain ultrastructure (fascicular thylakoids and type C cell division) is characteristic of the Microcoleaceae and Coleofasciculaceae families. An integrated analysis that included 16S rRNA gene phylogeny, conserved protein phylogeny and whole-genome comparisons indicated the unique position of BBK-W-15, thus supporting the proposed delineation of the new genus Limnofasciculus . Through characterisation by morphology, 16S, ITS and genomic analysis, a new cyanobacterium of the family Coleofasciculaceae Limnofasciculus baicalensis gen. et sp. nov. was described.

Cyanobacterial expansion is harmful to the environment, the ecology of Lake Baikal and the economy of nearby regions and can be dangerous to people and animals. Since 2011, the process of colonisation of the lake with potentially toxic cyanobacteria belonging to the genus Tychonema has continued. An understanding of the mechanism of successful expansion of Tychonema requires scrutiny of biological and genomic features. Tychonema sp. BBK16 was isolated from the coastal zone of Lake Baikal. The morphology of BBK16 biofilm was studied with light, scanning electron and confocal microscopy. The biofilm is based on filaments of cyanobacteria, which are intertwined like felt; there are also dense fascicles of rope-like twisted filaments that impart heterogeneity to the surface of the biofilm. Genome sequencing, intergenomic comparisons and phylogenetic analyses indicated that Tychonema sp. BBK16 represent a new species related to planktic cyanobacterium Tychonema bourrellyi , isolated from Alpine lentic freshwater. Genome investigation revealed the genes possibly responsible for the mixotrophic lifestyle. The presence of CRISPR-Cas and restriction modification defence mechanisms allowed to suggest the existence of phages infecting Tychonema sp. BBK16. Analysis of CRISPR spacers and prophage-derived regions allowed to suggest related cyanophages. Genomic analysis supported the assumption that mobile elements and horizontal transfer participate in shaping the Tychonema sp. BBK16 genome. The findings of the current research suggest that the aptitude of Tychonema sp. BBK16 for biofilm formation and, possibly, its mixotrophic lifestyle provide adaptation advantages that lead to the successful expansion of this cyanobacterium in the Baikal's conditions of freshwater lake environments.

This article characterises viral fraction metatranscriptomes (smaller than 0.2 µm) from the pelagic zone of oligotrophic Lake Baikal (Russia). The study revealed the dominance of transcripts of DNA viruses: bacteriophages and algal viruses. We identified transcripts similar to Pithovirus sibericum , a nucleocytoplasmic large DNA virus (NCLDV) isolated from the permafrost region of Eastern Siberia. Among the families detected were RNA viruses assigned to Retroviridae, Metaviridae, Potyviridae, Astroviridae, and Closteroviridae. Using the PHROG, SEED subsystems databases, and the VOGDB, we indicated that the bulk of transcripts belong to the functional replication of viruses. In a comparative unweighted pair group method with arithmetic mean (UPGMA) analysis, the transcripts from Lake Baikal formed a separate cluster included in the clade with transcripts from other freshwater lakes, as well as marine and oceanic waters, while there was no separation based on the trophic state of the water bodies, the size of the plankton fraction, or salinity.

An area of discolored water 50 m wide and 30 m long was found in September 2017 close to the dam of the Irkutsk hydroelectric power station. Water from this spot was sampled for investigation in the present study. Microscopic analysis revealed that the suspended matter in the sample was composed of clumps of filaments, vegetative cells, akinetes and heterocysts that formed short filaments and solitary cells. This matter was found to consist of partially degraded cells of the cyanobacterium Dolichospermum lemmermannii . Nucleotide sequencing of DNA isolated from the biomass revealed the presence of the sxtA gene which is involved in the synthesis of saxitoxin. Water from the polluted area contained 600 ± 100 μg L -1 saxitoxin as measured by HPLC-MS with pre-column modification of the toxin with 2,4-dinitrophenylhydrazine. Immunoassay analysis (ELISA) showed a concentration of saxitoxins in the water of 2900 ± 900 μg L -1 . Hydrochemical and microbiological analyses suggested the contaminated area appeared as a result of a D. lemmermannii bloom, followed by its decay and release of saxitoxin and nutrients. The present paper describes the results of a case study. Better understanding of the phenomenon will depend on the possibility to perform implementation of a large-scale monitoring program.

Based on second generation sequencing (MiSeq platform, Illumina), we determined the genetic diversity of T4-like bacteriophages of the family Myoviridae by analysing fragments of the major capsid protein gene g23 in the plankton of Lake Baikal. The sampling depth in our study was significantly higher than in those obtained by the Sanger method before. We obtained 33 701 sequences of the g23 gene fragments, 141 operational taxonomic units (OTUs) of which were identified. 86 OTUs (60.9%) had the closest relatives from lakes Bourget and Annecy, and 28 OTUs (19.8%) had the highest identity with the Baikal g23 clones, which had been previously identified in the northern and southern basins of the lake by the Sanger method. The remaining OTUs were similar to the clones from other ecosystems. We showed a high genetic diversity of T4-type bacteriophages and a genetic difference with the phage communities from other ecosystems., (© FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

A collection of heterotrophic bacteria consisting of 167 strains was obtained from microbial communities of biofilms formed on solid substrates in the littoral zone of Lake Baikal. Based on the analysis of 16S rRNA gene fragments, the isolates were classified to four phyla: Proteobacteria , Firmicutes , Actinobacteria , and Bacteroidetes . To assess their biotechnological potential, bacteria were screened for the presence of PKS (polyketide synthase) and NRPS (non-ribosomal peptide synthetases) genes. PKS genes were detected in 41 strains (25%) and NRPS genes in 73 (43%) strains by PCR analysis. The occurrence of PKS genes in members of the phylum Firmicutes (the genera Bacillus and Paenibacillus ) was 34% and NRPS genes were found in 78%. In Proteobacteria , PKS and NRPS genes were found in 20% and 32%, and in 22% and 22% of Actinobacteria , respectively. For further analysis of PKS and NRPS genes, six Bacillus and Paenibacillus strains with antagonistic activity were selected and underwent phylogenetic analysis of 16S rRNA genes. The identification of PKS and NRPS genes in the strains investigated was demonstrated among the homologues the genes involved in the biosynthesis of antibiotics (bacillaene, difficidine, erythromycin, bacitracin, tridecaptin, and fusaricidin), biosurfactants (iturin, bacillomycin, plipastatin, fengycin, and surfactin) and antitumor agents (epothilone, calyculin, and briostatin). Bacillus spp. 9A and 2A strains showed the highest diversity of PKS and NRPS genes. Bacillus and Paenibacillus strains isolated from epilithic biofilms in Lake Baikal are potential producers of antimicrobial compounds and may be of practical interest for biotechnological purposes., A collection of heterotrophic bacteria consisting of 167 strains was obtained from microbial communities of biofilms formed on solid substrates in the littoral zone of Lake Baikal. Based on the analysis of 16S rRNA gene fragments, the isolates were classified to four phyla: Proteobacteria , Firmicutes , Actinobacteria , and Bacteroidetes . To assess their biotechnological potential, bacteria were screened for the presence of PKS (polyketide synthase) and NRPS (non-ribosomal peptide synthetases) genes. PKS genes were detected in 41 strains (25%) and NRPS genes in 73 (43%) strains by PCR analysis. The occurrence of PKS genes in members of the phylum Firmicutes (the genera Bacillus and Paenibacillus ) was 34% and NRPS genes were found in 78%. In Proteobacteria , PKS and NRPS genes were found in 20% and 32%, and in 22% and 22% of Actinobacteria , respectively. For further analysis of PKS and NRPS genes, six Bacillus and Paenibacillus strains with antagonistic activity were selected and underwent phylogenetic analysis of 16S rRNA genes. The identification of PKS and NRPS genes in the strains investigated was demonstrated among the homologues the genes involved in the biosynthesis of antibiotics (bacillaene, difficidine, erythromycin, bacitracin, tridecaptin, and fusaricidin), biosurfactants (iturin, bacillomycin, plipastatin, fengycin, and surfactin) and antitumor agents (epothilone, calyculin, and briostatin). Bacillus spp. 9A and 2A strains showed the highest diversity of PKS and NRPS genes. Bacillus and Paenibacillus strains isolated from epilithic biofilms in Lake Baikal are potential producers of antimicrobial compounds and may be of practical interest for biotechnological purposes., (© 2018 Elena Sukhanova et al.)

A strain of Nostoc punctiforme was isolated from the bottom sediments of the oil seep at Gorevoy Utes (Central Baikal) at a depth of 890 m. The Baikal strain is highly similar (98-99%) to the N. punctiforme CCAP 1453/9 strain and the typical N. punctiforme PCC 73103 strain isolated from soil ecotopes. Based on the analysis of functional genes and mass spectrometry data, we determined that the strain can produce bioactive peptides and polyketides, but does not produce known cyanobacterial toxins, saxitoxin or its analogs, or microcystins. The peptides aeruginosinamide, aeruginosin 606, aeruginosin 98-A, kasumigamide C, and microginin 91-D were recorded in the metabolic profile of the strain. The major ion found in the MALDI mass spectrum is most likely to be an ion of a polyketide substance with unknown function.

OBJECTIVE Microvascular anastomosis is a basic neurosurgical technique that should be mastered in the laboratory. Human and bovine placentas have been proposed as convenient surgical practice models; however, the histologic characteristics of these tissues have not been compared with human cerebral vessels, and the models have not been validated as simulation training models. In this study, the authors assessed the construct, face, and content validities of microvascular bypass simulation models that used human and bovine placental vessels. METHODS The characteristics of vessel segments from 30 human and 10 bovine placentas were assessed anatomically and histologically. Microvascular bypasses were performed on the placenta models according to a delineated training module by "trained" participants (10 practicing neurosurgeons and 7 residents with microsurgical experience) and "untrained" participants (10 medical students and 3 residents without experience). Anastomosis performance and impressions of the model were assessed using the Northwestern Objective Microanastomosis Assessment Tool (NOMAT) scale and a posttraining survey. RESULTS Human placental arteries were found to approximate the M 2 -M 4 cerebral and superficial temporal arteries, and bovine placental veins were found to approximate the internal carotid and radial arteries. The mean NOMAT performance score was 37.2 ± 7.0 in the untrained group versus 62.7 ± 6.1 in the trained group (p < 0.01; construct validity). A 50% probability of allocation to either group corresponded to 50 NOMAT points. In the posttraining survey, 16 of 17 of the trained participants (94%) scored the model's replication of real bypass surgery as high, and 16 of 17 (94%) scored the difficulty as "the same" (face validity). All participants, 30 of 30 (100%), answered positively to questions regarding the ability of the model to improve microsurgical technique (content validity). CONCLUSIONS Human placental arteries and bovine placental veins are convenient, anatomically relevant, and beneficial models for microneurosurgical training. Microanastomosis simulation using these models has high face, content, and construct validities. A NOMAT score of more than 50 indicated successful performance of the microanastomosis tasks.

Molecular-genetic analysis of cyanophages of the family Myoviridae from the associated community of the endemic Baikal sponge Lubomirskia baicalensis was carried out based on the g20 gene fragment. A large cyanophage diversity according to the g20 marker gene was found in the sponge. The Baikal sponge cyanophages were shown to be similar to those inhabiting plankton. Moreover, specific cyanophage groups that are significantly different from all of the known groups inhabiting the Lake Baikal were revealed.

Cyanophages of the family Myoviridae were studied in Lake Hovsgol based on the analysis of g20 gene fragments. The analysis revealed the diversity of g20 cyanomyovirus sequences in Lake Hovsgol. It was found a great similarity of genes from the Lake Hovsgol and Lake Baikal. Distribution of closely related virus strains in these water bodies is attributed to close geographical location, direct water connection and similar hydrochemical parameters of the lakes.

A group of new meiotic division abnormalities affecting processes of phragmoplast centrifugal movement in successive cytokinesis in cereal pollen mother cells is described. These phenotypes present new information about motile phragmoplast formation and operation and confirm our model of centrifugal movements as B-ana-phase modification.

Two cyanobacterial strains, Pseudanabaena sp. 0411 and Synechococcus sp. 0431, were isolated from a sample collected in the Kotel'nikovskii hot spring of the Baikal rift. According to the results of light and transmission electron microscopy, as well as of the phylogenetic analysis of the 16S rRNA gene, these cyanobacteria were classified as Pseudanabaena sp. nov. and Synechococcus bigranulatus Skuja. The constructed phylogenetic tree shows that the studied strains are positioned in the clades of cyanobacteria isolated from hydrothermal vents of Asia and New Zealand, separately from marine and freshwater members of these genera, including those isolated from Lake Baikal.