• Journal of Microbiology
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• v.42 no.4
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• pp.357-360
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• 2004

For determining the process of bacterial aggregation, glucose was added into water from Lake Baikal which had been stored for seven months. In the presence of a higher concentration of glucose, the abun­dance of single bacteria and aggregates were higher, but the biovolumes of both bacteria were similar. Theses results mean that both free-living and aggregated bacteria have similar maximum sizes and that aggregates are forming with available organic materials. With available organic materials, the biovol­ume of aggregates becomes larger.

• Korean Journal of Microbiology
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• v.43 no.1
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• pp.14-18
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• 2007

The bacterial community structures at 2 sponge species belonging to the genus Baikalospongia and Lubomirskia in Lake Baikal were analyzed with fluorescent in situ hybridization (FISH) method. The total bacterial numbers in the genus Baikalospongia ranged from $7.2{\times}10^{7}\;to\;4.2{\times}10^{8}\;cells/ml$, and those in Lubomirskia from $1.2{\times}10^{8}\;to\;1.6{\times}10^{8}\;cells/ml$, while those of lake water were from $2.3{\times}7.7{\times}10^{5}\;cells/ml$. Total bacterial numbers in the sponges were $10^{3}-10^{4}$ times higher than those of lake water. In the genera Baikalospongia and Lubomirskia, the proportions of other unidentified bacterial groups to the Bacteria were 42.0-60.3% and 40.7-51.9%, respectively. These proportions were similar to those in lake water (22.6-46.3%). These results suggest that bacterial compositions in Lake Baikal water and sponges are highly unique.

• Journal of Microbiology
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• v.37 no.1
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• pp.10-13
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• 1999

The bacterial abundance, proportion of respiring bacteria, and bacterial community of southern Lake Baikal were analyzed at 1 m and 400m depths during winter. The total bacterial numbers were 5.1${\times}$105 cells ml-1 at 1 m and 2.5${\times}$105 cells ml-1 at 400 m depth, which are about half and quarter of the numbers of other lakes. The proportion of respiring bacteria was as low as 2.5% at 1 m and 1.4% at 400 m depth. Considering the amount of organic carbon which need to be degraded and low proportion of respiring bacteria, the bacteria could be assumed to have high activities. The EUB/DAPI ratios were 77 and 89% at 1 m and 400 m depths, respectively. Of the bacterial community, the other group was dominant at both depths, and gamma group of protebacteria followed next. But the beta group of proteobacteria and Cytophaga-Flavobacterium groups occupied very small proportions.

• Proceedings of the Microbiological Society of Korea Conference
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• 2005.05a
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• pp.194.1-194
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• 2005

• Korean Journal of Ecology and Environment
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• v.47 no.spc
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• pp.39-47
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• 2014

Sponge in Lake Baikal is an unique organism. Microorganisms in sponges are assumed as precious resources for bioactive materials. For understanding the bacterial community in Baikalian sponges by cultivation, 92 strains of bacteria were isolated from lake water and 2 species of sponges, Baikalospongia sp. and Lubomirskia sp., Thirty five bacterial strains are isolated from ambient water near the sponge, 27 bacterial strains from Baikalospongia sp., 30 bacterial strains from Lubomirskia sp.. As a result, 78.3% and 57.6% of isolated bacterial strains has amylase and protease activity respectively, while strains with cellulose and lipase activities were 38.0% and 34.8%. By 16S rRNA sequence analysis of selected strains, 13 strains which were isolated from Baikalospongia sp. were belong to Pseudomonas spp.. Whereas, 14 strains which were isolated from Lubomirskia sp. were Pseudomonas spp., Buttiauxella agrestis, Pseudomonas fluorescens, Yersinia ruckeri, Bacillus spp., Paenibacillus spp., Bacillus thuringiensis, Bacillus simplex, Brevibacterium spp., Acinetobacter lwoffii. In culture media, Pseudomonas spp. dominance was supposed that according to allelophathy.

• Korean Journal of Microbiology
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• v.47 no.2
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• pp.130-136
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• 2011

Five strains of Actinomyces were isolated from freshwater sponges, Baikalospongia and Lubomirskia, in Lake Baikal. By 16S rRNA sequencing, isolates were identified as Streptomyces griseoplanus, S. halstedii, S. violascens, S. flavovirens, and S. microflavus. Isolates had different characteristics of growth temperature, carbon utilization, enzyme activity, and cellular fatty acid composition. Optimum growth conditions of isolates were $30-37^{\circ}C$, pH 8-9, and 0-1.5% salt concentrations. Major fatty acid compositions were anteiso-$C_{15:0}$, iso-$C_{15:0}$, and iso-$C_{16:0}$. Strain ATS-BA-19 had DNase and chitinase activities and strain ATS-BA-16 had cellulase and protease activities. Colonies of strain ATS-BA-15 and ATS-BA-19 made inhibition zone of Pseudomonas aeruginosa.

• Korean Journal of Microbiology
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• v.40 no.3
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• pp.248-253
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• 2004

To scrutinize the physiological diversity by BIOLOG microplate, the carbon source utilization patterns of 168 strains of oligotrophic bacteria and 132 strains of psychrotrophic bacteria isolated from Lake Baikal during 2000 and 2002 were investigated. Eighty-six percent (56 strains) of oxidase test positive group (GN-NENT group) and 89 % (92 strains) of oxidase test negative group (GN-ENT group) among oligotrophic bacteria, and 82% (85 strains) of oxidase test negative group among psychrotrophic bacteria were able to utilize $\alpha$-D-glucose as a sole-carbon-source, and 93% (26 strains) of oxidase test positive group among psychrotrophic bacteria were able to utilize bromosuccinic acid as a sole-carbon-source. However, most strains except few oligotrophic bacteria with oxidase test negative group were not able to utilize $\alpha$-D-lactose as a sole-carbon-source. Most dominant genus among 300 strains was Pseudomonas (49 strains). Other dominant genera belonged to Salmonella, Serratia, Buttiauxella, Pantoea, Yersinia, Brevundimonas, Hydrogenophaga, Photorhabdus, Sphingomonas, and Xenorhabdus. Our results by BIOLOG identification system were able to provide basic data to determine community-level carbon source utilization patterns and to accomplish the efficient and reliable identification for microbial community structure in Lake Baikal.

• Proceedings of the Microbiological Society of Korea Conference
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• 2005.05a
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• pp.193.4-193
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• 2005

• Proceedings of the Microbiological Society of Korea Conference
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• 2005.05a
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• pp.190.4-190
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• 2005

• Journal of Microbiology and Biotechnology
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• v.15 no.5
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• pp.1135-1139
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• 2005

Psychrotrophic phenanthrene-degrading bacteria were identified in the sediment samples collected from Lake Baikal, Russia. Among 70 phenanthrene-degrading isolates, the seven that had the highest phenanthrene-degradation rates were identified by 16S rDNA sequencing. Isolate P25, identified as the Gram-positive rod-shaped organism Rhodococcus erythropolis, had the highest growth and degradation rate at $15^{\circ}C$. It could remove $26.0\%$ of 100 mg $1^{-1}$ phenanthrene in 20 days at $15^{\circ}C$, and degradation was less at $5^{\circ}C\;and\;25^{\circ}C$. The addition of surfactants to enhance degradation was tested. Brij 30 and Triton X-100 inhibited degradation at all surfactant concentrations tested, but Tween 80 stimulated phenanthrene degradation, especially at low concentrations. When $20{\times}$ CMC (critical micelle concentration) of Tween 80 was added, $38.0\%$ of 100 mg $1^{-1}$ phenanthrene was degraded in 12 days at $15^{\circ}C$. This psychrotrophic phenanthrene-degrading bacterium is a candidate for use in bioremediation of polycyclic hydrocarbon contamination in low temperature environments.