• Journal of Microbiology
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• v.42 no.4
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• pp.278-284
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• 2004

Changes in the soil bacterial community of a coniferous forest were analyzed to assess microbial responses to wildfire. Soil samples were collected from three different depths in lightly and severely burned areas, as well as a nearby unburned control area. Direct bacterial counts ranged from $3.3­22.6\times10^8\;cells/(g{\cdot}soil).$ In surface soil, direct bacterial counts of unburned soil exhibited a great degree of fluctuation. Those in lightly burned soil changed less, but no significant variation was observed in the severely burned soil. The fluctuations of direct bacterial count were less in the middle and deep soil lay­ers. The structure of the bacterial community was analyzed via the fluorescent in situ hybridization method. The number of bacteria detected with the eubacteria-targeted probe out of the direct bacterial count varied from $30.3\;to\;84.7\%,$ and these ratios were generally higher in the burned soils than in the unburned control soils. In the surface unburned soil, the ratios of $\alpha,\;\beta\;and\;gamma-proteobacteria,$ Cytoph­aga-Flavobacterium group, and other eubacteria groups to total eubacteria were 9.9, 10.6, 15.5, 9.0, and $55.0\%,$ respectively, and these ratios were relatively stable. The ratios of $\alpha,\;\beta\;and\;gamma-proteobacteria,$ and Cytophaga-Flavobacterium group to total eubacteria increased immediately after the wildfire, and the other eubacterial proportions decreased in the surface and middle layer soils. By way of contrast, the composition of the 5 groups of eubacteria in the subsurface soil exhibited no significant fluctuations dur­ing the entire period. The total bacterial population and bacterial community structure disturbed by wildfire soon began to recover, and original levels seemed to be restored 3 months after the wildfire.

• KSBB Journal
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• v.28 no.3
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• pp.157-164
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• 2013

Depending on season, mixed wastewater can show great deviations in terms of the influent ratios of tannery and seafood-wastewater. Increases in the ratio of tannery wastewater in influent water also result in increases in the concentration of chromium, which decreases the ratio of BOD/T-N so that the removal efficiency of organic and nitrogen pollutants in biological wastewater treatment deteriorates. No substantial differences occur in the ratios of Eubacteria/total bacteria as the ratio between tannery wastewater and seafood wastewater changes in the influent water. In contrast, the cell numbers and activities of Eubacteria and total bacteria significantly decline with increasing ratios of tannery wastewater in the influent water. Stable removal of organic and nitrogen pollutants by biological wastewater treatments leads to dominance of Proteobacteria groups in all biological treatment basins. In aeration and oxic basins, ${\gamma}$-Proteobacteria account for approximately 21% of the Eubacteria groups, at $1.9{\times}10^9{\sim}2.0{\times}10^9$ cells/mL, while in an anoxic basin, ${\beta}$-Proteobacteria account for approximately 19% of the Eubacteria groups, at $1.3{\times}10^9$ cells/mL. However, a substantial decline in dominance of approximately 11% occurs for ${\gamma}$-Proteobacteria in aeration and oxic basins and about 1% for ${\beta}$-Proteobacteria in an anoxic basin. Mixed wastewater that undergoes extensive property changes of the influent water shows an efficiency of biological treatment that is greatly influenced by the ratio of dominant Proteobacteria groups.

• Journal of Microbiology
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• v.42 no.4
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• pp.285-291
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• 2004

The soil bacterial community and some inoculated bacteria were monitored to assess the microbial responses to prescribed fire in their microcosm. An acridine orange direct count of the bacteria in the unburned control soil were maintained at a relatively stable level $(2.0\~2.7\times10^9\;cells/g^{-1}{\cdot}soil)$ during the 180 day study period. The number of bacteria in the surface soil was decreased by fire, but was restored after 3 months. Inoculation of some bacteria increased the number of inoculated bacteria sev­eral times and these elevated levels lasted several months. The ratios of eubacteria detected by a flu­orescent in situ hybridization (FISH) method to direct bacterial count were in the range of $60\~80\%$ during the study period, with the exception of some lower values at the beginning, but there were no definite differences between the burned and unburned soils or the inoculated and uninoculated soils. In the unburned control soil, the ratios of $\alpha-,\beta-\;and\;\gamma-subgroups$ of the proteobacteria, Cytophaga-Fla­vobacterium and other eubacteria groups to that of the entire eubacteria were 13.7, 31.7, 17.1, 16.8 and $20.8\%,$ respectively, at time 0. The overall change on the patterns of the ratios of the 5 subgroups of eubacteria in the uninoculated burned and inoculated soils were similar to those of the unburned con­trol soil, with the exception of some minor variations during the initial period. The proportions of each group of eubacteria became similar in the different microcosms after 6 months, which may indicate the recovery of the original soil microbial community structure after fire or the inoculation of some bac­teria. The populations of Azotobacter vinelandii, Bacillus megaterium and Pseudomonas fluorescens, which had been inoculated to enhance the microbial activities, and monitored by FISH method, showed similar changes in the microcosms, and maintained high levels for several months.

• Proceedings of the Zoological Society Korea Conference
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• 2001.10a
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• pp.148.3-148
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• 2001

• Korean Journal of Microbiology
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• v.38 no.4
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• pp.287-292
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• 2002

The composition of bacterial communities was detected in surface water of Cheonho Reservoir dominated by cyanobacteria, using fluorescent in situ hybridization (FISH) method. Total bacterial numbers were very high ranging from 0.6～$1.3{\times}10^7 \cells{\cdot}ml^-1$, whereas the ratio of Eubacteria to total bacteria was 29.8~45.8%, which was lower than that in other freshwater ecosystems. On average only 2.1% of DAPI-stained bacteria were detected by FISH with probes for $\alpha$, $\beta$, and $\gamma$-groups, respectively. Unknown eubacteria which was not bound to any probes except EUB 338, was relatively high. On the other hand, the Cytophaga-Flavobacterium group increased following the change of dominant species from Anabaena sp. to Microcystis sp. This result showed that bacterial communities could be affected by phytoplanktons, especially cyanobacteria.

• KSBB Journal
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• v.20 no.5 s.94
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• pp.387-391
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• 2005

Totally 16,299 conservative genes, commonly found in 13 thermophilic and hyperthermophilic bacteria, were analyzed. All genes were belong to W 67 COGs (clusters of orthologous groups of proteins). COGs related to protein metabolism were 80 among 167 COGs. Conservative genes were not limited only thermophiles and hyperthermophiles, meaning thermal stability is independent of specific protein. However reverse gyrase was only found in all hyperthermophilic archaebacteria and eubacteria, meaning DNA stability is important in hyperthermophiles. Hyperthermophilic eubacteria and thermophilic archaebacteria had different position between phylogenetic tree of gene content and 165 rRNA gene. Thermophilic archaebacteria hyperthermophilic eubacteria and archaebacteria had similar values by the statistical analysis of distance values with 167 COGs in each organism.

• KSBB Journal
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• v.17 no.6
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• pp.560-565
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• 2002

A COG(clusters of orthologous groups of proteins) algorithm was used to detect conserved genes within Proteobacteria and to figure out their relationships. Restricting comparison to the sequences of 42 procaryotes, 33 eubacteria and 16 Proteobacteria, the number of conserved genes was increased. All analyzed procaryotes shared 75 COGs. COG0195, COG0358 and COG0528 were only represented by the 42 procaryotes. Sixtyfour COGs were added as conserved genes in 33 eubacteria. Each Proteobacteria group has a unique repertoire of COGs. Metabolic COGs were more diverse in the beta Proteobacteria group than in the other groups. These results could be used to determine the origins and the evolutionary relationships of Proteobacteria. The possibilities of detecting new biological molecules is high in phylogenetically related organisms, hence the identification of useful proteins by using this algorithm is possible.

• Korean Journal of Microbiology
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• v.34 no.3
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• pp.169-174
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• 1998

To define the structure and diversity of bacterial communities in the aqutic ecosystem, Lake Soyang, the largest artificial reservoir in Korea, a new method, fluorescent in situ hybridization was applied. This technique relies on the specific hybridization of the nucleic acid probes to the naturally amplified intracellular rRNA. By this method, the bacterial community composition of Lake Soyang and bacterial numbers belong to eubacteria, proteobacteria and Cytophaga-Flavobacterium group were estimated. Total bacterial numbers ranged from $0.3{\times}10^6{\sim}2.0{\times}10^6cells{\cdot}ml^{-1}$, and vertical profile of total bacteria showed the peak at 2 and 5 m depths. The ratio of eubacteria to total bacteria were 22~100% and varied with depth and season. The percentage of Proteobacteria ${\alpha}$-group ranged 2.6~66.7%, ${\beta}$-group 4.5~53.5%, ${\gamma}$-group 4.6~76.7% and Cytophaga-Flavobacterium group 2.1~35.9%. Also, bacteria] community had spatial and temporal characteristics. The dominant groups were ${\beta}$-group in winter, ${\gamma}$-group in spring and early summer and ${\alpha}$-group in summer.

• Korean Journal of Microbiology
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• v.38 no.1
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• pp.31-37
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• 2002

For elucidating the correlation between the eubacterial community structure and environmental parameters in Nammae Reservoir located in Kyungsan, Kyungbuk, the bacterial community structure and their structure affecting environmental parameters were analyzed using Fluorescent In Situ Hybridization (FISH) monthly over year. $\alpha$ . $\beta$ . $\gamma$-subclasses of Proteobacteria and Cytophaga-Flavobacterium (CF) group known as dominant bacterial group in freshwater were detected in 3 stations over year. The ratio of each subclass to total bacteria was determined; $\alpha$.$\beta$ . $\gamma$-subclasses and CF group varied in the range of 4.0~29.2%, 1.7~25.8%, 1.8~12.8%, 4.9~36.3%, respectively and there was no substantial differences between stations. In terms of the correlation between each group specific bacteria and environmental parameters such as temperature, SS, pH, DOC, NH$_4$-N, NO$_3$-N, PO$_4$-P, standing crops of algae, the results were as follows: 1) total bacterial numbers correlated positively with temperature, SS and DOC, 2) Eubacteria positively with DOC and Chl-$\alpha$, 3)${\gamma}$-subclass positively with DOC, and 4) CF group positively with standing crops of chlorophyceae, 5) whereas $\beta$-subclass bacteria correlated negatively with standing crop of cyanobacteria and that of total algae.

• Korean Journal of Microbiology
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• v.33 no.4
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• pp.257-261
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• 1997

To scrutinize the bacterial community composition of Lake Soyang in winter, bacterial numbers belonging to Eubacteria, Proteobacteria and Cytophaga-Flavobacterium group were estimated by using 16S and 23S rRNA targeted oligonucleotide probes. Total bacterial numbers ranged from $0.7{\times}10^6$ to $1.1{\times}10^6cells{\cdot}ml^{-1}$, and vertical profile of total bacteria showed a peak at 5 m depth. The ratio of eubacteria to total bacteria were 34~90% and at 5 m and 10 m depths those were low exhibiting, 39 and 34%, respectively. The percentage of proteobacteria ${\alpha}$-group ranged 10.8~28.7%, ${\beta}$-group 4.5~53.5%, ${\gamma}$-group 4.9~35.5% and Cytophaga-Flavobacterium group 6.1~21.1%. The dominant groups were ${\beta}$-group at 0, 2 and 5 m, ${\gamma}$-group at 10 m, ${\alpha}$-group at 30 m and Cytophaga-Flavobacterium group at 50 m depth. In winter season, Lake Soyang can be divided into three layer, 0~2 m, 5~10 m and 30~50 m, by the bacteria community composition. By this method, new informations about aquatic ecosystem were developed.