• Journal of Life Science
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• v.28 no.3
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• pp.369-375
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• 2018

Mycoplasma genitalium has 367 conserved genes and the smallest genome among mono-culturable prokaryotes. Conservative metabolic pathways were examined among M. genitalium and 14 prokaryotes, one hyperthermophilic exosymbiotic archaeon Nanoarchaeum equitans and 13 intracellular eubacteria of plants or insects, with fewer conserved genes than M. genitalium. They have 11 to 71 metabolic pathways, however complete metabolic pathways ranged from 1 to 24. Totally, metabolic pathway hole is very high due to the lack of 45.8% of the enzymes required for the whole metabolic pathways and it could be suggested that the shared metabolic pathway with the host's enzyme would work or the essential substances are host dependent. The number of genes necessary for mass transfer through the cell membrane is also very low, and it may be considered that the simple diffusion or the protein of the host will function in the cell membrane of these prokaryotes. Although the tRNA charging pathway was distributed in all 15 prokaryotes, each has 5-20 tRNA charging genes. This study would give clues to the understanding of the metabolic pathways of intracellular parasitic bacteria of plant and endosymbiotic bacteria of insects, and could provide basic data for prevention of crop damage, development of insect pests and human medicines.

• Korean Journal of Environmental Biology
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• v.27 no.1
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• pp.20-30
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• 2009

To study reproductive dynamics of a Gold-spotted pond frog (Rana chosenica) population located at Gangnae, Cheongwon, Chungbuk, Korea, we monitored the population over 207 days between April 17$^{th}$ 2007 and December 18$^{th}$ 2008 using a drift fence accompanied with 20 pitfall traps. The population was located in an agricultural wetland, compromising three small ponds. Gold-spotted pond frogs immigrated into the wetland between April 16$^{th}$ and June 17$^{th}$ and emigrated from the wetland between September 21$^{st}$ and November 12$^{th}$. Precipitation showed a positive correlation with the number of migrated frogs in Autumn 2007 and Spring 2008, but other environmental factors such as air and water temperatures and relative humidity did not show any significant relationships. In general, small frogs first migrated into and from the wetland, but the trend was not strong. Female gold-spotted pond frogs were bigger than males. During the autumn migration, small frogs of which snout-vent length was smaller than 20 mm were found, indicating that successful breeding occurred in the population. Our results could be useful to conserve this endangered species in Korea.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2001.11a
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• pp.373-374
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• 2001

우리나라에서 관측된 황사현상에 관한 연구는 대기 중 부유분진을 포집하여 황사의 입경 분포 비교 및 화학적 성분분석(이 등, 1986; 이 등, 1989)을 효시로 1980년대 부터 시작되었으며, 최근까지 부유분진의 양 및 물리화학적 특성 및 이동경로 등에 대해 연구되어 왔다(전 등1999). 본 연구는 황사와 대기중의 생물입자에 대해 충남 서산지역에서 시료를 채취하여 조사하였다. (중략)

• Journal of Life Science
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• v.29 no.1
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• pp.123-128
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• 2019

The use of 16S rDNA is commonplace in the determination of prokaryotic species. However, it has limitations, and there are few studies at the genus level. We investigated conserved genes and metabolic pathways at the genus level in 28 strains of 13 genera of prokaryotes using the COG database (conserved genes) and MetaCyc database (metabolic pathways). Conserved genes compared to total genes (core genome) at the genus level ranged from 27.62%(Nostoc genus) to 71.76%(Spiribacter genus), with an average of 46.72%. The lower ratio of core genome meant the higher ratio of peculiar genes of a prokaryote, namely specific biological activities or the habitat may be varied. The ratio of common metabolic pathways at the genus level was higher than the ratio of core genomes, from 58.79% (Clostridium genus) to 96.31%(Mycoplasma genus), with an average of 75.86%. When compared among other genera, members of the same genus were positioned in the closest nodes to each other. Interestingly, Bacillus and Clostridium genera were positioned in closer nodes than those of the other genera. Archaebacterial genera were grouped together in the ortholog and metabolic pathway nodes in a phylogenetic tree. The genera Granulicella, Nostoc, and Bradyrhizobium of the Acidobacteria, Cyanobacteria, and Proteobacteria phyla, respectively, were grouped in an ortholog content tree. The results of this study can be used for (i) the identification of common genes and metabolic pathways at each phylogenetic level and (ii) the improvement of strains through horizontal gene transfer or site-directed mutagenesis.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.512-512
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• 2017

날로 심각해지는 해수 오염, 유류사고, 해파리에 의한 인명피해 및 발전소의 경제적 피해사고, 해양 쓰레기 등과 같은 해양 환경 문제가 발생하고 있다. 이러한 해양환경문제를 해결하기위해 생물학적 방법과 물리적 방법이 있으나 생물학적 방법은 개체군과 종류의 변화로 그 적용이 어려운 실정이고, 물리적 방법은 지속적인 제거를 위한 비용적인 문제와 인부 및 자원봉사자의 안전문제가 발생한다. 따라서 에어버블을 이용한 각종 친환경적 방법이 주목받고 있다. 본 연구에서는 에어버블 차단막의 차단율을 증가시키기 위해 현장조건 내에서 에어버블의 거동특성에 대한 실험을 하였다. 실험을 위해 회류식 개수로 에어버블 거동실험장치를 제작하였다. 실험장치는 길이 8.1m, 높이 1.2m, 폭 0.7m이며, 두께 10mm의 투명 아크릴를 사용하여 에어버블의 거동을 관찰 할 수 있게하였다. 대형펌프를 사용하여 물이 회류함을 통해 흐름유속을 만들어 현장조건을 고려하였다. 에어버블을 분사하기 위해 압축공기 저장탱크와 연결된 분사구가 있으며, 노즐의 크기(0.5mm~1.0mm)로 분사량을 조절하고 분사압은 별도의 조절장치를 이용하여 0~5bar 범위의 분사압 조절을 가능하게 하였다. 초고속 카메라와 3축유속계를 사용하여 에어버블의 이동경로, 유속 및 에어버블의 거동을 측정하였다. 실험을 통한 구간별 에어버블의 거동 분석 결과, 상승속도는 분사구에서 분출되는 구간인 0~0.8m 에서는 상승속도가 증가하고, 0.8~1.2m구간에서는 속도가 다시 상승하는 경향을 확인하였다. 이는 수표면에 가까워질수록 수압이 작아져서 에어버블의 크기가 커짐에 따라 부력이 커짐으로 판단된다. 같은 이유로 분사량이 많을수록 상승속도도 같이 증가되는 것으로 나타났다. 유속에 따른 거동은 유속을 0.1m/s~0.5m/s로 조정하여 유속별 에어버블이 수표면까지 도달하는 거리, 속도 및 이동경로를 분석하였다. 유속과 에어버블이 수표면까지 도달하는 거리는 비례하여 증가하는 것을 확인하였다. 실험결과를 바탕으로 조건에 따른 에어버블 거동 경험식을 도출하였다. 본 실험은 회류식 개수로 에어버블 거동실험장치를 활용하여 에어버블 거동 경험식을 제시하였으며, 이를 바탕으로 에어버블 차단막 기술 개발을 위한 기초자료로 이용될 수 있을 것이다.

• Ecology and Resilient Infrastructure
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• v.11 no.1
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• pp.1-10
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• 2024

Influx of exotic fishes is the reason of the destruction of ecosystem and biodiversity on fishes habitats. This study was conducted to detect the movement of in grand ecological park along river and stream. Purpose of study is to realize the movement of exotic fishes. In this study, Monitoring was conducted in Daijeo ecological park. The movement of exotic fishes can indicate the habitats and the possible spread in Nakdong river and Daijeo ecological park.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.6 no.1_2
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• pp.49-57
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• 1973

Based on the fork length data of 1960 and on the fishery statistical data of 1968, 1970 and 1971, a research was made on the migration of the Pacific saury in the waters off the eastern coast of Korea. The population is divided into four groups in terms of size as shown in Fig. 5. The four groups demonstrate more or less different pattern of migration, both temporally and spatially. Northward migration is brought out in order of size, i. e., the smaller move northward earlier than the larger do, and the order is reverse in the case of southward migration. The migration routes of each size group are presented in Fig. 8. Whether the fish takes its course to the north or the south, its distribution centroid within the fishing grounds is traced in general following the line between $130^{\circ}$ and $130^{\circ}$130^{\circ$x. long., although longitudinally a pronounced annual bias is found in its month position. The moving pattern of the distribution centroid is assumed to be related with the abundance of each group to a considerable extent.

• Proceedings of the Korean Society of Applied Pharmacology
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• 2001.11a
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• pp.104-104
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• 2001

Ras는 세포의 성장과 분화 등 여러 필수적인 세포기능에 없어서는 안될 중요한 역할을 담당하며 Ras가 mutation되면 암 등의 치명적인 결과를 초래한다. Ras 발현은 유방암에서 tumor aggressiveness의 지표로 간주되고 있으며 유방세포의 침습성과 연관이 있다고 알려져 있으므로 ras가 전이과정에 미치는 영향에 관한 연구는 중요한 의미를 갖는다. 본 연구의 선행연구결과, H-ras와 N-ras 모두 transformed phenotype을 나타내지만 H-ras 만이 암전이에 있어서 중요한 침윤성을 유도하는 것을 밝혔다. 이 결과는 MCF10A 세포에서 H-ras와 N-ras에 의한 신호전달경로가 각각 다른 생물학적 전이활성을 나타냄을 시사한다. 세포의 이동성은 침습성에 있어서 결정적인 역할을 하므로, 본 연구에서 H-ras와 N-ras로 형질전환된 MCF10A세포에서 이동성을 시험한 결과, 세포의 이동성이 N-ras가 아닌 H-ras MCF10A 세포에서만 크게 증가된다는 것을 보았다. 이는 침습성을 나타내는 H-ras가 세포의 이동성을 증가시키는데 작용한다는 것을 말한다. H-ras에 의해 유도된 침습성과 이동성에 대한 분자적 기전에 관하여 연구하기 위하여 H-ras MCF10A와 N-ras MCF10A 세포에서 Ras의 downstream effector들, 특히 mitogen-activated protein kinases(MAPKinases)들인 JNK1, ERK, p38의 활성화를 살펴본 결과 p38 MAPKinase가 H-ras MCF10A 세포에서 현저하게 활성화됨을 보았다. p38 MAPKinase 저해제인 SB203580를 처리하던지 dominant negative p38 (DN p38) transfectant로 p38을 불활성화시켰을 때 세포침습성 및 이동성이 저해되는 결과를 얻었다. SB203580 처리한 H-ras MCF10A 세포에서 전이에 관여하는 효소인 MMP-2 분비가 감소되었다. H-ras에 의해 유도된 침습성과 이동성은 DN JNK1 transfectant에서는 변화가 없었으나 DN MEK transfectants에서는 유의성있게 감소되었다. 이상의 결과를 종합하면, MCF10A 세포의 침윤성과 이동성에는 p38 MAPKinase 활성이 중심적인 역할을 하며, JNK 활성은 영향을 미치지 않고, ERK-1/2 활성은 충분하지는 않으나 필요하다는 것을 알 수 있었다.

• Korean Journal of Environmental Biology
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• v.26 no.4
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• pp.377-384
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• 2008

A cell is the product of a long period of evolution and can be represented as an optimized system (homeostasis). Stimuli from the outside environment are received by sensory apparatus on the surface of the cell and transferred through complicated pathways and eventually regulate gene expression. These signals affect cell physiology, growth, and development, and the interaction among genes in the signal transduction pathway is a critical part of the regulation. In this study, the interactions of deletion mutants and overexpression of the extracopies of the genes were used to understand their relationships to each other. Also, green fluorescent protein (GFP reporter gene) was fused to the regulatory genes to elucidate their interactions. Cooverexpression of the two genes in extracopy plasmids suggested that patS acts at the downstream of hetR in the regulatory network. The experiments using gfp fusion in different genetic background cells also indicated the epistasis relationships between the two genes. A model describing the regulatory network that controls cell development is presented.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.15 no.1
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• pp.36-40
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• 2010

Ballast water has been known as a major vector for global dispersal of toxic dinoflagellates and other microalgae. In this study, biodiversity in ships’ ballast water was examined using a dinoflagellate-oriented PCR primer set and species-specific real-time PCR. While motile dinoflagellates could be observe at very low cell densities by light microscopy,a wide range of dinoflagellate taxa including parasitic and phototrophic pico-dinoflagellates as well as harmful species to marine fish/shellfish was detected when techniques for cloning/sequencing of SSU rDNA of sample cells were used. Present result suggests that molecular methods including species-specific PCR primers may offer rapid and accurate detection of invasive species in ballast water.