• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1974.06a
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• pp.124.2-124
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• 1974

전보에서 분리ㆍ등정한 섬유소 분해력이 강한 세균을 이용하여 볏짚에서 단세포단백을 생산할 목적으로 각종 알카리에 의한 볏짚의 전처리 효과를 살펴보았다. 즉, 규정농도의 알카리 용액에 24시간 실온에서 침지하여 중성이 될때까지 수세하고 건조시켜 무기염 용액에 4％첨가하여 5일간 진탕 배양한 후 균체량 증가 및 기질의 감소를 측정하여 다음과 같은 결과를 얻었다.(중략)

• KSBB Journal
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• v.8 no.2
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• pp.185-191
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• 1993

Highly stable $O_2$-evolving cells and thylakoid membranes have been obtained from the cyanobacterium, Synechococcus PCC7002, by immobilization with polyvinylalcohol(PVA). The absorption peak showed the blue-shift of about 3 nm after immobilization of intact cells and thylakoid membranes as well as isolation of thylakoid membranes. Photosynthetic electron transport activities, especially PS II activity showed greater stability in the PVA-immobilized cells and thylakoid membranes when stored at $4^{\circ}C$ than in those at $25^{\circ}C$. When the cells were threated at higher temperature, the level of Fo and Fv increased. After imobilization, however, Fo showed no change. This suggests that the immobilization can protect against the damages of PS II complex, especially a water-spiliting system, by heat treatment.

• Applied Microscopy
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• v.12 no.2
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• pp.11-22
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• 1982

The morphological development of Mycoplasma pneumoniae attached to solid surfaces was examined by light and electron microscopies. Critical point drying and carbon replication techniques revealed that during the growth cycle of developing microcolonies, the morphological form coincided with the pH of the culture. M. pneumoniae appeared to have a well defined morphology associated with age of the culture. The organisms were dimorphic, with round cells capable of reproduction and segments consisting of a spindle shaped body with one pointed and one knob-like end. Starting with single cells, there were the following stages in the development of a culture: replication stage through binary fission and segmentation, stage of confluency, and a degeneration stage into rough spherical forms. The round cells appearrd to replicate by binary fission during the lag and early log phases of growth, while spindle segments replicated by segmentation during most of the logarithmic growth. The growth of the filaments and replication of the segments occured at the knob-like ends, showing a type of polarity, and formed a meshwork across the surface. This development could be cycled under favorable growth conditions, but the culture aged and when the conditions became adverse(e.g. pH 6.8 or lower), filamentous cells converted to spherical forms, losing their reproductive capability.

• Journal of Hydrogen and New Energy
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• v.24 no.1
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• pp.20-28
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• 2013

Photobiological hydrogen production by nitrogen-fixing unicellular cyanobacteria has long been considered to be an environmentally sound and very promising method for the future supply of renewable clean energy. Using six Korean nitrogen-fixing unicellular cyanobacterial strains and the Synechococcus sp. strain Miami BG043511 we performed cultivation experiments to find out the strain-specific optimal temperature for population growth and $H_2$ production. Under $20^{\circ}C$ the population growth of all the tested strains was significantly retarded in contrasts to the faster and higher growth under 25, 30 or $35^{\circ}C$. The highest growth rates in all the 7 strains were measured under $30^{\circ}C$ while the maximal biomass yields were under $30^{\circ}C$ (strains CB-MAL 026, 054, and 055) or $35^{\circ}C$ (strains 002, 031, 058, and Miami BG043511). The difference between the maximal biomass yields at $30^{\circ}C$ and $35^{\circ}C$ was not greater than 10%. The quantity of photobiologically produced $H_2$ was only slight larger under $35^{\circ}C$ than that under $20^{\circ}C$. Our result may suggest a two-step process of $H_2$ production which includes rapid and sizable production of biomass at $30^{\circ}C$ and the following high $H_2$ production at $20^{\circ}C$ by the test strains of marine nitrogen-fixing unicellular cyanobacteria.

• Environmental Mutagens and Carcinogens
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• v.17 no.2
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• pp.71-77
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• 1997

The single cell gel electrophoressis(SCGE) assay, also known as the comet assay, is a rapid, simple, visual and sensitive technique for measuring and analysing DNA breakage in mammalian cells. The SCGE or comet assay is a promising test for the detection of DNA damage and repair in individnal cells. It has widespread potential applications in DNA damage and repair studies, genotoxicity testing and biomonitoring. In this microgel electrophoresis technique, cells are embedded in agarose gel on microscope slides, iysed and electrophoresed under alkaline conditions. Cells with increased DNA damage display increased migration of DNA from the nucleus towards the anode. The length of DNA migration indicates the amount of DNA breakage in the cell. The comet assay is also capable of identifying apoptotic cells which contain highly fragmented DNA. Here we review the development of the SCGE assay, existing protocols for the detection and analysis of comets, the relevant underlying principles determining the behaviour of DNA and the potential applications of the technique.

• Journal of Life Science
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• v.2 no.1
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• pp.11-19
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• 1992

pheromone은 생물의 체내에서 합성되고 체외로 분비되어 동종개체에 작용함으로써 특정의 생리적 변화를 유발하는 물질이다. 생물 중에서는 성장의 어느 단계에서 pheromone과 같은 물질이 관여하고 있다는 것이 알려져 있다. 또한, 단세포생물에서 세포 외로 분비하여 2개의 세포를 서로 접합시키는 물질이 있는데 이러한 물질을 성pheromone이라 부르고 있다. 특히, 효모 버섯, 조류, 섬모충류에서 연구되고 있다. 효모는 성접합형을 달리하는 두 균주가 상호pheromone을 분비, 수용하여 성분화를 행하여가고 있다. 그리고 세균에 있어서도 pheromone 양상의 물질이 세포 외로 분비되고 이 물질에 의하여 세균의 생리적 조건에 영향을 주는 예가 있다. 지금까지 알려져 있는 미생물의 성 pheromone에 대하여 크게 나누어 보면 지용성 성 pheromone과 수용성 성 pheromone으로 대별할 수 있다. 본 총설에서는 세균과 자낭균효모, 담자균효모유래의 성 pheromone 중 peptide(수용성) 성 pheromone에 대해서만 집약하였다.

• Microbiology and Biotechnology Letters
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• v.5 no.1
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• pp.1-4
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• 1977

In order to produce cellulosic single cell protein from the cellulosic wastes, 252 strains of cellulose assimilating bacteria were isolated front 225 sources of microorganisms such as decomposed wood, compost soils, soils, cotton fabrics and useless paper. The isolates were investigated for their ability to utilize cellulose as carbon source. One of them was screened by its stong cellulose assimilating abililty, and was identified as Cellulomonas flavigena.

• Journal of Hydrogen and New Energy
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• v.22 no.5
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• pp.663-670
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• 2011

Under a daily photoperiod of 14h light and 10h dark synchronization of cell cycle in Korean Cyanothece spp. strains and $Synechococcus$ sp. strain Miami BG043511 was analyzed as to be applicable to enhanced hydrogen production. For all strains peaks of double cell were observed during the light period of a daily cycle. Peaks of maximal cell size measured by a coulter counter appeared at the peak of double cells observed under light microscope reconfirming the synchronization of daily cell cycle. The cell cycle synchronization became weakened within two days when treated with continuous illumination. Rapid detection of the peak time of double cell percentage by coulter counters may contribute to quasi-realtime feedback control for efficient production of photobiological hydrogen by unicellular cyanobacterial strains.

• Applied Biological Chemistry
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• v.29 no.1
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• pp.36-43
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• 1986

In order to produce cellulosic single cell protein from the cellulose, 163 strains of cellulose assimilating bacteria were isolated from 95 sources and one of them was screened by its strong cellulose assimilating activity. and was identified as Sporocytophaga congregate A-7. The optimum temperature and pH for cellulase production were $30^{\circ}C$ and 6.0, and the optimum temperature, pH and heat stability of the enzyme were $50^{\circ}C$, 7.0 and below $55^{\circ}C$. When the bacteria was cultured in fermentor, the specific growth rate was $0.034hr^{-1}$ and when the bacteria was mixed cultured with Candida guilliermondii var. guilliermondii, the specific growth rate of the bacteria and yeast were $0.06hr^{-1}$ and $0.08hr^{-1}$ respectively and total cell dry weight was $4{\sim}5g/l$.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.208.1-208.1
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• 2016

히드라란 단세포 생물로써 강장동물에 속한다. 촉수가 많이 있으며, 그 촉수에는 독이 있다. 번식 방식으로는 출아법을 이용한다. 출아를 할 때에는 한 마리가 아닌 여러 마리의 히드라가 동시에 출아를 하기도 하며, 출아를 하고 있는 히드라는 촉수가 들어난 순간부터 먹이 섭취가 가능해진다. 이 출아법을 이용하여 번식을 하는 히드라가 DBD처리를 했을 시, 히드라 출아에 차이를 보인다면 다른 생물에게도 DBD 처리를 했을 시, 영향을 미친다고 생각하고 실험을 진행하였다. DBD(Dielectric Barrier Discharge)는 두 전극 사이에 유전체층이 있으며, 외부에서 교류 전압을 가해준다. 그러면 유전체 사이에서 방전이 발생되는데, 방전된 것을 플라즈마라고 한다. DBD라는 유전체 장벽 방전으로써 주위를 이온화 시켜 만드는 플라즈마에 유전체를 씌어 생물에게 최대한 해가 되지 않도록 만든 것이다. 유전체 장벽 방전에ROS(Reactive Oxygen Species)라는 산소와 결합된 기체들이 생성된다. DBD로 인해서 생성되는 ROS를 히드라에 처리했을 경우 히드라 출아수에 변화를 통해서 해를 끼치는 정도를 알아보고자 하였다. 그 결과 아르곤 기체에 의한 ROS로 처리한 히드라는 대조군 보다 히드라의 출아수의 변화가 있는 것으로 관찰되었고, 공기를 이용하여 방전한 DBD의 ROS로 처리한 히드라는 대조 군과 비교하여 큰 변화가 없어 보였다. 따라서 아르곤 대기압 DBD플라즈마를 이용하여 만든 ROS가 히드라에게 직접적인 영향을 준 것으로 보였다. 이 결과를 토대로 아르곤DBD를 이용한 ROS 처리는 생물에게 영향을 줄 수 있다는 것을 이 실험을 통해 간접적으로 확인해 볼 수 있었다.