RESUMO
Cyanobacteria of the genera Anabaena and Microcystis, containing genes for the synthesis of-microcystins (hepatotoxic cyanotoxins) were found for the first time in the coastal zone of Lake Baikal near-the village of Turka, where a tourism and recreational complex were constructed. According to the enzyme-immunoassay, microcystin concentration in water was 0.17 ± 0.01 µg/L. Using 16S rRNA gene pyrosequencing, we found 3936 sequences in the eubacterial community of central basin of Lake Baikal. The summer bacterioplankton in both littoral and pelagic areas of the lake was dominated by the phylum Cyanobacteria, whereas a higher diversity of cyanobacteria was recorded in the plankton of the littoral zone. Moreover, the-potentially toxic Anabaena and Microcystis were detected in this area.
Assuntos
Cianobactérias/isolamento & purificação , Lagos/microbiologia , Cianobactérias/enzimologia , Cianobactérias/genética , Monitoramento Ambiental , Marcadores Genéticos/genética , Genótipo , Transaminases/genética , Transaminases/metabolismoRESUMO
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.
Assuntos
Genes Virais , Variação Genética , Lagos/virologia , Myoviridae/genética , Poríferos , Animais , SibériaAssuntos
Cianobactérias/genética , Lagos/microbiologia , Saxitoxina/genética , Microbiologia da Água , Animais , Técnicas de Tipagem Bacteriana , Cianobactérias/classificação , Cianobactérias/metabolismo , Primers do DNA/química , DNA Bacteriano/análise , DNA Bacteriano/genética , Lagos/química , Reação em Cadeia da Polimerase , Saxitoxina/biossíntese , Saxitoxina/isolamento & purificação , SibériaRESUMO
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.
Assuntos
Bacteriófagos/genética , Cianobactérias/virologia , Variação Genética , Myoviridae/genética , Filogenia , Bacteriófagos/classificação , Lagos/microbiologia , Lagos/virologia , Mongólia , Myoviridae/classificação , Análise de Sequência de DNARESUMO
Bacterial diversity of two Lake Baikal endemic sponges characterized by different life forms, branching Lubomirskia baicalensis and cortical Baikalospongia sp., was studied using the method of 454 pyrosequencing of the 16S rRNA gene fragments. In the communities associated with L. baicalensis and Baikalospongia sp., 426 and 428 OTUs, respectively, were identified. In microbial associations of these spong- es, 24 bacterial phyla were identified, with predominance of Bacteroidetes, Proteobacteria, and Actinobacteria. Analysis of the taxonomic composition of bacterial communities of the sponges was carried out by search of the dominant phylotypes within the phylum level cluster. Comparison of bacterial associations of the sponges with Lake Baikal bacterioplankton revealed both the shared OTUs and the unique ones characteristic of the studied species.
Assuntos
Consórcios Microbianos/genética , Filogenia , Poríferos/microbiologia , Actinobacteria/genética , Actinobacteria/isolamento & purificação , Animais , Bactérias/genética , Lagos , Plâncton , Proteobactérias/genética , Proteobactérias/isolamento & purificação , RNA Ribossômico 16S , SibériaAssuntos
Bacteroidetes/genética , Biofilmes/crescimento & desenvolvimento , Cianobactérias/genética , Plâncton/genética , Proteobactérias/genética , RNA Ribossômico 16S/genética , Bacteroidetes/classificação , Bacteroidetes/crescimento & desenvolvimento , Bacteroidetes/isolamento & purificação , Biodiversidade , Biofilmes/classificação , Cianobactérias/classificação , Cianobactérias/crescimento & desenvolvimento , Cianobactérias/isolamento & purificação , Lagos/microbiologia , Metagenoma , Consórcios Microbianos/genética , Filogenia , Plâncton/classificação , Plâncton/crescimento & desenvolvimento , Plâncton/isolamento & purificação , Proteobactérias/classificação , Proteobactérias/crescimento & desenvolvimento , Proteobactérias/isolamento & purificação , RNA Ribossômico 16S/classificação , Federação Russa , Análise de Sequência de DNARESUMO
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.
Assuntos
Cianobactérias/classificação , Fontes Termais/microbiologia , Microbiologia da Água , Cianobactérias/genética , Cianobactérias/isolamento & purificação , Cianobactérias/ultraestrutura , Microscopia , Microscopia Eletrônica de Transmissão , Filogenia , Reação em Cadeia da Polimerase , RNA Bacteriano/genética , RNA Ribossômico 16S/genética , Sibéria , Synechococcus/classificação , Synechococcus/genética , Synechococcus/isolamento & purificação , Synechococcus/ultraestruturaRESUMO
A new filamentous cyanobacterial strain BAC 9610 was isolated from the lake Baikal pelagial. Data obtained by light, scanning, and transmission electron microscopy, along with 16S rRNA gene sequence analysis, allowed the bacterium identification as Trichormus variabilis, previously known as Anabaena variabilis. Trichormus is a cyanobacterial genus not presented in the list of Baikal plankton algae; A. variabilis also has not been previously detected in Baikal phytoplankton. T. variabilis nitrogen fixation ability was demonstrated. The gene responsible for nitrogen fixation, nifH, was identified by PCR and was partially sequenced. No hepatotoxin synthesis genes were revealed in the strain.