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Diversity of Cyanobacterial Species and Phylotypes in Biofilms from the Littoral Zone of Lake Baikal
Ekaterina G. Sorokovikova,Olga I. Belykh,Anna S. Gladkikh,Oleg V. Kotsar,Irina V. Tikhonova,Oleg A. Timoshkin,Valentina V. Parfenova 한국미생물학회 2013 The journal of microbiology Vol.51 No.6
The majority of naturally occurring biofilms contain numerous microorganisms that have not yet been cultured. Additionally, there is little information available regarding the genetic structure and species diversity of these communities. Therefore, we characterised the species diversity, structure and metagenome of biofilms grown on stones and steel plates in the littoral zone of Lake Baikal (East Siberia,Russia) by applying three different approaches. First, light microscopy enabled identification of the species diversity of biofilm-forming cyanobacteria on different substrates with the dominance of Rivularia rufescens, Tolypothrix limbata,Chamaesiphon fuscus, Сh. subglobosus, and Heteroleibleinia pusilla. Additionally, scanning electron microscopy was used to show the spatial structure of biofilms. Finally, sequence analysis of 30,660 16S rRNA clones indicated a high diversity within the biofilm communities, with the majority of the microbes being closely related to Cyanobacteria (8–46% sequences),Proteobacteria (14–43%), and Bacteroidetes (10–41%). Rivularia sp., Pseudanabaena sp., and Chamaesiphon spp. were the dominant cyanobacterial phylotypes.
Nina A. Bondarenko,Olga I. Belykh,Ludmila P. Golobokova,Olga V. Artemyeva,Natalia F. Logacheva,Irina V. Tikhonova,Irina A. Lipko,Tatyana Ya. Kostornova,Valentina V. Parfenova,Tamara V. Khodzher,안태석,조영 한국미생물학회 2012 The journal of microbiology Vol.50 No.1
Biological entities and gradients of selected chemicals within the seemingly barren ice layers covering Lake Baikal were investigated. Ice cores 40–68 cm long were obtained from inshore and offshore sites of Southern Lake Baikal during the cold period of a year (March-April) in 2007 and 2008. In microscopic observations of the melted ice, both algae and bacteria were found in considerable numbers (>103 cells/L and >104 cells/ml, respectively). Among all organisms found, diatom was generally the most predominant taxon in the ice. Interestingly, both planktonic and benthic algae were present in considerable numbers (2–4×104 cells/L). Dominant phototrophic picoplankton were comprised of small green algae of various taxa and cyanobacteria of Synechococcus and Cyanobium. The bacterial community consisted mostly of short rod and cocci cells, either freeliving or aggregated. Large numbers of yeast-like cells and actinomycete mycelium were also observed. Concentrations of silica, phosphorus, and nitrate were low by an order of magnitude where biota was abundant. The profile of the ice could be interpreted as vertical stratification of nutrients and biomass due to biological activities. Therefore, the organisms in the ice were regarded to maintain high activity while thriving under freezing conditions. Based on the results, it was concluded that the freshwater ice covering the surface of Lake Baikal is considerably populated by extremophilic microorganisms that actively metabolize and form a detritus food chain in the unique large freshwater ecosystem of Lake Baikal.
Nikolay A. Gaevsky,Vladimir I. Kolmakov,Olga I. Belykh,Irina V. Tikhonova,정요찬,안태석,Valentina A. Nabatova,Anna S. Gladkikh3 한국미생물학회 2011 The journal of microbiology Vol.49 No.5
Microcystis aeruginosa is a well-known Cyanobacterium responsible for the formation of toxic water blooms around the world. Shallow, warm, and eutrophic reservoirs provide the most favourable conditions for M. aeruginosa development. Numerous studies have been devoted to this species, but there still is a necessity to develop additional approaches for the monitoring of cyanobacteria in reservoirs. In this study, M. aeruginosa in the water column of a hypereutrophic Siberian reservoir was investigated by fluorescence, light, and electron microscopy as well as genetic analysis using a mcyE marker. Here, we demonstrate the genetic diversity and features of the fluorescence spectra for different ecotypes of this species. We suggest that a fluorescence approach can be used to identify M. aeruginosa in a natural environment in order to increase the effectiveness of ecological monitoring and water quality evaluation.