• 한국해양학회지
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• v.24 no.3
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• pp.148-156
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• 1989

This investigation was performed in eutrophic lake within the framework of a series of studies to evaluate the significance of gram reaction for both bacterioplankton and attached bacteria in the dynamics of organic materials at various aquatic ecosystems. In Lake Kasumigaura as a representative of the highly eutrophic freshwater environments, the gram-stain characteristics of the bacterial community changed with the influx of pulses of phytoplankton, as those in the meso trophic environments. The predominency of the gram-negative forms in the bacterial community was about 57% for bacterioplankton and about 53% for attached bacteria. The statistical analysis of the difference of these two distributions showed that these communites were different. Both gram-negative and gram-positive bacteria attached to particles were shown to effect the formation and degradation of particulate organic matter. Gram-negative bacteria plankton participate exclusively in the dynamics of dissolved organic matter.

• Journal of the Korean Chemical Society
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• v.48 no.2
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• pp.144-150
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• 2004

Various experimental factors that affect the separation of bacteria were investigated using capillary electrophoresis. At different buffer concentrations, gram-positive bacteria and gram-negative bacteria showed somewhat different migration behavior under high electric filed. The separation efficiency was also investigated as a function of concentration of bacterium injected into the capillary. In order to separate bacteria as the difference of size and shape, water soluble polymers such as poly(ethylene)oxide (PEO), polyvinylpyirrolidone (PVP), and dextran were studied. PEO, which is more flexible and has lower steric hinderance, showed the best separation efficiency. The mixed bacteria sample of Micrococcus lysodeikticus as gram-positive bacteria and Aerobacter aerogenes as gram-negative bacteria were successfully analyzed with PEO.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.49-49
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• 2018

라오스의 Houay Pano 유역은 상업적 조림으로 인해 2011년부터 2013년까지 급속한 토지이용 변화를 겪어왔다. 본 연구는 이러한 토지이용변화가 박테리아 거동에 어떠한 영향을 주는지 이해하기 위해 Soil and Water Assessment Tool (SWAT) 모형을 활용한 박테리아 거동 모델링을 수행하였다. SWAT 모형은 수치 표고 모델, 토양 특성, 토지 이용 등의 정보를 종합하여, 유역 내수량 및 수질의 변화를 모의할 수 있는 모형으로, 본 연구는 대표적인 분원성 지표 세균 (Fecal Indicator Bacteria)인 대장균 (Escheichia coli, E. coli)을 대상으로 모델링을 수행하였다. SWAT 모형은 지표면 위 박테리아를 1)식물 위, 2)토양 용액상, 3)토양 입자상으로 구분하여 모의한다. 각 상태로 분할된 박테리아는 소멸 (die-off), 씻김 (wash-off), 침투, 표면 유출을 통한 수계로의 이동 등의 단계를 통하여 유역 내에서 거동한다. 본 연구는 서로 다른 기후의 영향을 배제하기 위해 각 토지이용 시나리오를 (2011, 2012, 2013) 실제 기후 조건과 동일 기후(2011-2013 평균) 조건으로 분류하여 분석하였다. 실제 기후 조건에서 SWAT 모형은 표면 유출, 토사 유출, E. coli 거동에 대해 2011년부터 2012년까지 감소, 2012년부터 2013년까지 증가로 모두 동일한 양상을 모의하였다. 이는 강수량의 양상과 동일한 것으로, 강수량이 표면 유출의 양을 결정하고, 달라진 표면 유출에 따라 토사 유출과 E. coli 거동이 결정되기 때문이다. 하지만 동일 기후 조건에서는, E. coli 거동 동인인 표면 유출과 토사 유출이 비교적 일정해짐에 따라, 각 상태로 분할된 박테리아의 초기 부하량값이 E. coli 거동을 결정하는 주된 요인임을 확인 할 수 있었다. 따라서 초기 부하량 분할에 활용되는 엽면적 지수 (Leaf Area Index)와 분배계수 (BACTKDDB)의 정확도가 요구된다. 추가적으로 본 연구는 박테리아의 유입원인 비료 모델링과, LAI를 활용한 박테리아 초기 부하량 산정, 토양 특성 변수와 토지 이용 변수의 분리, 지하수를 통한 박테리아 거동 등을 중심으로 SWAT 모형의 한계점과 개선점을 제시하였으며, 본 연구 결과는 토지이용변화가 박테리아 거동에 주는 영향을 모형적으로 이해하고, 또한 추후 박테리아 모델링 개발에 도움을 줄 것으로 예상된다.

• Environmental Analysis Health and Toxicology
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• v.19 no.3
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• pp.295-305
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• 2004

본 연구에서는 유전자 재조합 발광 박테리아를 이용하여 농약에 대한 박테리아의 스트레스 반응과 세포 독성을 분석하였다. 15종류의 농약에 대하여 유전자 손상, 생물막 손상, 산화적 손상 및 단백질 손상을 측정할 수 있는 발광 박테리아와 독성 유무로 인한 세포 독성을 측정할 수 있는 발광 박테리아, 5종을 이용하여 스트레스 반응을 분류하고 세포 독성 정토를 분석하였다. 그 결과, 농약의 화학적 구조가 박테리아의 스트레스 반응에 영향을 미치며, 산화과정이 진행 됨에 따라 독성의 작용 기작이 변하는 것을 확인 할 수 있었다. 이와 같은, 유전자 재조합 발광 박테리아를 이용한 생물체내의 독성 메커니즘에 대한 분석은 생태계 유해물질들에 의한 독성을 분석하고 예상하기 위해 적용될 수 있을 것이다.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.7
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• pp.833-838
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• 2007

In this study, adhesion and transport of bacteria in positively-charged media was investigated with batch and column experiments. Bacterial species used in this study was Escherichia coli ATCC 11105(length: 2.2 ${\mu}m$, diameter: 0.6 ${\mu}m$) and media used were quartz sand(particle size distribution: 0.5-2.0 mm, mean diameter: 1.0 mm) and iron-coated sand. Batch results indicate that bacterial adhesion increased as the content of iron-coated media increased. At iron-coated media 0%(quartz sand 100%), around 46% of bacteria was adhered to media while at iron-coated media 100%(quartz sand 0%) about 97% was attached. Column results also show that bacterial adhesion was enhanced with an increase of iron-coated media content. As the iron-coated media content increased from 0 to 100%, bacterial adhesion increased from 8 to 94%. The experimental results demonstrate that positively-charged media could influence transport of bacteria in porous media.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.4
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• pp.395-402
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• 2017

Recently, many researches on crack healing and repairing technique using bacteria which can produce vital-reacted calcite have been proposed. This study is for a basic research on repair material with slime formation through bacteria and deals with durability evaluation for coating materials containing bacteria-forming slime. For the work, 4 types of bacteria (Rhodobacter capsulatus, Rhodopseudomonas palustris, Bacillus thuringiensis, and Bacillus subtilis) and 2 types of nutrient conditions are considered, and several tests covering strength evaluation under sulfate condition, accelerated chloride diffusion, and UV (Ultrasonic Velocity) measurement are performed. Strength improvement in coating materials containing bacteria is evaluated in spite of even exposure to sulfate attack to 7 days. Chloride diffusion coefficient and UV properties are also improved except for the case of Rhodopseudomonas palustris. With resistance of slime to long term exposure and aerobic conditions for bacteria longevity, the proposed bacteria shows an engineering feasibility for repair material of RC structure exposed harsh environment.

• 한국해양학회지
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• v.30 no.5
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• pp.426-435
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• 1995

In order to assess the significance of ciliate grazing on bacterial population in carbon flow of the estuarine pelagic ecosystem of the Mankyung and Dongjin river (MD estuary), abundance and biomass of ciliates and grazing rate on bacteria of small (<40 um) ciliates were measured. Saplings were carried out four times from October 1993 to March 1995 in the estuarine system. Ciliates smaller than 40 um occupied more than 49.5% of total ciliates abundance. Clearance rate of small ciliates ranged from 18.0 to 16.3 nl cell/SUP -1/ h/SUP -1/. As bacterial abundance increased, ciliate's clearance rate decreased, suggesting that bacterial abundance effects on ciliate's grazing rate. Ciliate grazing rate was equal to 0.1 to 12.2% of bacterial productivity, and the ratio of ciliate ingestion over bacterial production increased exponentially with the increase of bacterial abundance (r$^2$=0.62, p$\leq$0.001). It seems that the effect of ciliate grazing on bacteria would be small in coastal waters and large in more eutrophic waters of high bacterial abundance. Carbon supplied by ciliate grazing on bacteria was avg. 3.1% of carbon amount required for the ciliate maximum productivity. Thus, the ecological role of ciliate in microbial loop was probably more important as a final consumer than as a direct consumer of bacteria.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.11
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• pp.847-854
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• 2011

To deal with issues from global climate changes, renewable bioenergy has become important. Algae have been regarded as a good resource for biorefinery and bioenergy, and also have potential capability to remove nutrient and non-decompositional pollutants for wastewater advanced treatment. Although algal-bacterial ecological interaction would be a crucially important factor in using algae for wastewater advanced treatment and resource recovery from wastewater, very little is known about ecological interaction between algae and bacteria in a real wastewater environment. In this study, under a real municipal wastewater condition, we characterized wastewater pollutant treatability and bacterial communities in response to growth of Ankistrodesmus gracilis SAG278-2, which can grow in wastewater and has a high lipid contents. The growth of algal population using the wastewater was inhibited by increase in wastewater bacteria while bacterial survival and cellular decay rate were not influenced by the algal growth. Removals of recalcitrant organic matters and total nitrogen were improved in the presence of algal growth. According to T-RFLP and statistical analysis, algal growth affected time-course changes in bacterial community structures. The following 16S rRNA gene amplicon, cloning results showed that the algal growth changes in bacterial community structure, and that bacterial populations belonging to Sediminibacterium, Sphingobacterium, Mucilaginibacter genera were identified as cooperative with the algal growth in the wastewater.

• Journal of Marine Life Science
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• v.4 no.2
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• pp.53-62
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• 2019

Heterotrophic bacteria are a major member of the microbial loop in the marine ecosystem and play an important role in the biogeochemical cycle decomposing organic matter. Therefore study of bacterial variation is important to understand the material cycle and energy flow of marine ecosystems. We investigated the monthly variations of bacteria and environmental factors in the Youngsan River estuary, and the correlation between bacteria and phytoplankton biomass (chlorophyll-a) including size-structure. As a result, bacteria of the Youngsan River estuary were higher in the surface than in the bottom layer, and higher in the summer than in winter. And the closer to the dike, the abundance increased, and it increased to the peaks in August, September, and June 2019 at the station closest to the dike. The chlorophyll-a also increases at the stations and time when the bacterial abundance was high and they correlates positively displaying no difference between size fractions. The results indicate that organic matter derived from phytoplankton has an effect on bacterial variation but no size-dependent effects. In addition, the seasonal pattern of bacteria increasing in proportion to the water temperature suggests the effect of water temperature on the growth of bacteria. No association of bacterial abundance variation with nutrient supply due to freshwater input was observed. In this study, dissolved oxygen was depleted and hypoxia was observed for a short time when a strong stratification was not developed. This may be resulted from the supply of organic matter from phytoplankton and the consumption of oxygen due to bacterial decomposition.

• The Science & Technology
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• v.35 no.3 s.394
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• pp.19-19
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• 2002

바닷물 속의 미생물세계는 매우 역동적이며 먹고 먹히는 긴박한 육상의 정글과 같다. 해양 박테리아를 위협하는 포식자와 기생자 그리고 먹고 먹히는 박테리아의 생존세계를 본다.