pH 충격에 의한 Chlamgdomonas acidophila ( Cholorophyta ) , UTCC 122 의 생리적 변화에 관한 연구

이경(Kyung Lee),기장서(Jang Seu Ki),김세화(Say Wa Kim),한명수(Myung Soo Han),최영길(Young Kil Choi),유광일(Kwang Il Yoo) 한국하천호수학회 2002 생태와 환경 Vol.35 No.3

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남조세균 흔들말목(Cyanobacteria, Oscillatoriales) 해양 균주의 16S rRNA와 rpoB 유전자 변이

천주용,이민아,기장서,Cheon, Ju-Yong,Lee, Min-Ah,Ki, Jang-Seu 한국미생물학회 2012 미생물학회지 Vol.48 No.4

본 연구는 남조세균 흔들말목(Cyanobacteria, Oscillatoriales)의 16S ribosomal RNA (rRNA) 및 RNA polymerase beta subunit(rpoB) 유전자를 대상으로 염기서열 변이 및 분자계통학적 특성을 분석한 것이다. 흔들말목 rpoB 유전자는 16S rRNA보다 유전자 변이(유전거리: rpoB=0.270, 16S=0.109)가 큰 것으로 조사되었으며, 통계적으로 유의한 차이를 보였다(Student t-test, p<0.001). 흔들말목 16S rRNA와 rpoB의 계통분석에서 유사한 계통 분지형태를 보였으며, rpoB 유전자가 높은 해상도를 갖고 있어 흔들말목 분류군을 더 명확하게 구분하였다. 또한, parsimony 분석을 통해 rpoB 유전자가 16S rRNA 보다 2.40배 빠르게 진화하는 것으로 파악되었다. 본 연구결과는 rpoB 유전자가 흔들말목의 분자계통 및 종 분류 연구에 매우 유용하다는 것을 제시해 준다. In this study, we investigated molecular divergences and phylogenetic characteristics of the 16S ribosomal RNA (rRNA) and RNA polymerase beta subunit (rpoB) gene sequences from the order Oscillatoriales (Cyanobacteria). The rpoB of Oscillatoriales showed higher genetic divergence when compared with those of 16S rRNA (p-distance: rpoB=0.270, 16S=0.109), and these differences were statistically significant (Student t-test, p<0.001). Phylogenetic trees of 16S rRNA and rpoB were generally compatible; however, rpoB tree clearly separated the compared Oscillatoriales taxa, with higher phylogenetic resolution. In addition, parsimony analyses showed that rpoB gene evolved 2.40-fold faster than 16S rRNA. These results suggest that the rpoB is a useful gene for the molecular phylogenetics and species discrimination in the order Oscillatoriales.

남조세균 Anabaena 종 구분을 위한 RNA Polymerase Beta Subunit (rpoB) 유전자 염기서열 분석

천주용,이민아,기장서,Cheon, Ju-Yong,Lee, Min-Ah,Ki, Jang-Seu 한국미생물학회 2011 미생물학회지 Vol.47 No.3

남조세균 Anabaena (Cyanobacteria, Nostocales)는 담수 생태계에서 녹조 현상을 유발하거나 일부 종은 간독소(hepatotoxin)를 갖고 있어 수질관리 차원에서 주목 받아 왔다. 본 연구는 Anabaena RNA polymerase beta subunit (rpoB) 유전자 염기서열을 규명하였으며, 분류학적 분자 마커로 사용하기 위하여 이들 염기서열의 특성을 평가하였다. Anabaena rpoB 유전자는 16S rRNA 유전자와 비교하여 염기 유사도가 낮으며 유전자 변이가 큰 것으로 분석되었으며, 통계적으로 유의한 차이를 보였다(Student t-test, p<0.01). Parsimony 분석을 통해 rpoB 유전자가 4.8배의 속도로 빠르게 진화하는 것으로 파악되었다. 또한 rpoB 유전자 phylogeny 분석에서 16S rRNA tree보다 높은 해상도로 Anabaena 균주를 명확하게 구분해 주었다. 본 연구 결과는 Anabaena의 종 식별, 분자계통 분류, 분자적 검출을 위해 rpoB 유전자가 매우 효과적이라는 것을 제시해 준다. Anabaena (Cyanobacteria, Nostocales) are important for water quality controls, because they are often responsible for freshwater green tides; moreover, some species are reported to produce hepatotoxin. In this study, we sequenced RNA polymerase beta subunit (rpoB) gene of Anabaena, and evaluated their sequences for the potential use of a molecular taxonomic marker in this taxon. Anabaena rpoB showed low DNA similarity and high genetic divergences when compared those of 16S rRNA, and the molecular differences were statistically significant (Student t-test, p<0.01). Parsimony analyses showed the rpoB gene evolves 4.8-fold faster than 16S rRNA. In addition, phylogeny of the rpoB gene separated each Anabaena strain more clearly compared with a 16S rRNA tree. These results suggest that the rpoB gene is a useful marker for the molecular phylogenetics and the species discrimination of Anabaena.

Re-description of Chrysaora pacifica (Goette, 1886) (Cnidaria, Scyphozoa) from Korean Coastal Waters: Morphology and Molecular Comparisons

Hye Eun Lee,윤원덕,채진호,기장서 한국해양과학기술원 2016 Ocean and Polar Research Vol.38 No.4

The nomenclature of the sea nettle jellyfish from Korea was initially described as Dactylometra quinquecirrha Agassiz, 1862. However its identity has been questioned on the basis of its local distribution and molecular data. Here, we examined morphology and DNA sequences of nuclear rDNA using specimens collected from southern Korean waters in August 2014. Based on morphological characteristics (bell size, umbrella pattern, number of tentacles and lappets) and distribution locality, we reassign the Korean D.quinquecirrha to Chrysaora pacifica (Goette, 1886), and provide a re-description accordingly. The molecular identity of C. pacifica was further confirmed by comparison of nuclear ribosomal DNA sequences.

Description of an unrecorded diatom Fragilaria saxoplanctonica Lange-Bertalot & Ulrich (Bacillariophyceae) from Paldang Reservoir in Korea

Ha-Eun Lee,Taehee Kim,이상득,기장서 국립생물자원관 2023 Journal of species research Vol.12 No.4

Diatoms are unicellular eukaryotic microalgae, and they are highly diversified in aquatic environments. We describe an unrecorded diatom species Fragilaria saxoplanctonica Lange-Bertalot & Ulrich (Bacillariophyceae) collected from Paldang Reservoir, Korea, on 4 April 2022. The valve was needle shaped and narrowly rectangular, its ends were rounded, and no spines were found on the outline of their valves. The valve was 67.2-70.2μm in length and 1.4-2.9μm in width. The ratio of width-to-length was 1 : 23.2-50.1. The pattern of striation was alternate or opposite, and the number of striae in 10μm was 24-26. Molecular comparisons of the 18S rDNA and rbcL sequences showed that it belonged to the genus Fragilaria. These morphological and phylogenetic results confirmed that our species was F. saxoplanctonica, and it was the first record in Korea.

Nuclear rDNA characteristics for DNA taxonomy of the centric diatom Chaetoceros (Bacillariophyceae)

Joon-Baek Lee,Ju-Yong Cheon,이진환,허성범,기장서 한국조류학회I 2010 ALGAE Vol.25 No.2

The genus Chaetoceros provides highly diversified diatoms in marine systems. Morphological descriptions of the genus are well-documented, yet the DNA taxonomy of Chaetoceros has not been satisfactorily established. Here, the molecular divergences of the 18S-28S rDNA of Chaetoceros were assessed. DNA similarities were relatively low in both 18S (93.1 ± 3.9%) and 28S rDNA (81.0 ± 4.6%). Phylogenies of the 18S, 28S rDNAs showed that Chaetoceros was divided according to individual species, clustering the same species into single clades. Statistical analysis with corrected genetic (p-) distance scores showed that nucleotide divergence of Chaetoceros 28S rDNA significantly differed from that of 18S rDNA (Student’s t-test, p < 0.05). This finding suggests that the 28S rDNA may be treated as a more suitable marker for species-level taxonomic distinctions of Chaetoceros.

2012년 한강 서울통과 구간의 식물플랑크톤 군집 특성

이연수,김태희,이만덕,기장서,Lee, Yeon-Su,Kim, Taehee,Lee, Man-Duck,Ki, Jang-Seu 한국환경생물학회 2020 환경생물 : 환경생물학회지 Vol.38 No.2

한강은 서울 및 수도권 지역의 수자원으로 다양하게 이용되고 있어 지속적인 모니터링과 관리가 필요하다. 본 연구는 2012년도 한강 하류의 식물플랑크톤 군집구조와 계절별 변화를 규명하였다. 현장시료는 서울통과 구간의 상류(팔당대교), 중류(청담대교), 하류(성산대교)에서 월 1회 채집하였으며, 현장에서 수온, 용존산소, pH, 전도도를 측정하였다. 환경요인은 3개 정점에서 유사한 값으로 조사되었으며, 수온은 2~30℃ 범위이고 DO는 4.8~19.1 mg L^-1로 온대지역의 전형적인 패턴을 보였다. 식물플랑크톤 수는 990 cells mL^-1(팔당대교, 12월)~2.9×10⁴ cells mL^-1(성산, 3월)의 변동이었고, 엽록소는 0.6 ㎍ L^-1(팔당대교, 12월)~10.3 ㎍ L^-1(성산, 3월)로 세포수와 같은 양상을 보였다. 조사된 식물플랑크톤 군집은 규조류 37종, 녹조류 29종, 남조류 11종, 와편모조류 2종 등 총 75속 95종 이었다. 계절별 최저 출현은 9종(5월, 팔당대교)에서 최고 35종(12월, 청담)으로 변화폭이 컸다. 봄철(3~5월)에 평균 15종으로 적은 출현종수를 보였으며, 겨울철(12월)에 평균 27종으로 다른 계절보다는 다양한 출현 종수를 보였다. 규조류는 여름철을 제외하고 모든 정점과 계절에서 가장 우점하였다. 반면 녹조류와 남조류는 여름철과 가을철에 산발적으로 높은 우점률을 나타냈지만, 제 1우점군은 아니었다. 출현빈도 10% 이상 되는 종으로, 규조류는 Aulacoseira granulate, Cyclotella sp., Stephanodiscus hantzschii이며, 녹조류는 Actinastrum hantzschii이고, 남조류는 Microcystis sp.였다. 본 연구는 2012년 한강 하류의 식물플랑크톤 군집 변화 및 현존량, 우점종의 변화를 분석한 것으로, 향후 진행될 연구들과 환경변화에 따른 한강의 수질 및 식물플랑크톤 군집 변화를 이해하기 위한 좋은 기초 자료가 될 것이다. This study reported on the phytoplankton community and seasonal changes in the Seoul passage section and downstream in the Han River in 2012. Field samples were collected monthly from the upper (Paldang), middle (Cheongdam), and downstream(Seongsan) areas of the Seoul passage section. Water temperature, DO, pH, and conductivity were measured at each station. All environmental factors measured were recorded similarly at the three stations. The water temperature ranged from 2 to 30℃ and the dissolved oxygen ranged from 4.8 to 9.1 mg L^-1, showing typical patterns of temperate regions. The phytoplankton cell concentrations ranged from 990 cells mL^-1 (Paldang, December) to 2.9×10⁴ cells mL^-1 (Seongsan, March), and the chlorophyll-a content showed similar patterns to the cell numbers. The phytoplankton community was comprised of 75 genera and 95 species, including 37 diatoms, 29 Chlorophyta, 11 cyanobacteria, and two dinoflagellates. The number of species that appeared seasonally varied greatly, from nine species (Paldang, May) to 35 species (Cheongdam, December). Diatoms were the most dominant in all stations and seasons, except in summer. In contrast, chlorophytes and cyanobacteria showed sporadic high numbers in the summer and fall seasons. Four diatoms Stephanodiscus hantzschii f. tenuis, S. hantzschii, Fragilaria sp., and Aulacoseira spp., a chlorophyte Actinastrum hantzschii, and a cyanobacterium Microcystis sp. were each present in proportions greater than 10%. This study provides fundamental data from phytoplankton communities and environmental factors in the Han River for understanding water quality for long-term environmental monitoring.

폴리스티렌 폼을 사용한 슬래브의 뚫림전단에 관한 실험적 연구

이환구(Lee, Hwan-Gu),김승훈(Kim, Seung-Hun),강인석(Kang In-Suk),이한승(Lee, Han-Seung),이기장(Lee, Ki-Jang) 한국콘크리트학회 2008 한국콘크리트학회 학술대회 논문집 Vol.2008 No.5

샌드위치형 점탄성 감쇠장치가 적용된 철골조 바닥구조의 진동 해석

이종호(Lee Jong-Ho),홍갑표(Hong Kap-Pyo),전호민(Chun Ho-Min),이성수(Lee Seoung-Soo),이기장(Lee Ki-Jang),윤광섭(Yoon Kwang-Sup) 대한건축학회 2009 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.29 No.1(구조계)

The long span floor structure systems increase the vibration when people are waling on the slab. Using the viscoelastic damper is one of effective method to increase damping ratio. The purpose of this study was to analyze floor vibration of the steel structure that used viscoelastic sandwich damper. Viscoelastic sandwich damper reduces the vibration without additional weight or structure materials. But we have not enough studies about steel structure that used viscoelastic sandwich damper. So we analyzed the vibration test of steel structure that used viscoelastic sandwich damper and compare the data with ANSYS FEM analysis.

철근콘크리트 이방향 중공 하프슬래브의 휨성능에 관한 실험적 연구

김상우(Kim Sang-Woo),황현복(Hwang Hyun-Bok),황현식(Hwang Hyun-Sik),이기장(Lee Ki-Jang),이동근(Lee Dong-Gun),이정윤(Lee Jung-Yoon) 대한건축학회 2009 大韓建築學會論文集 : 構造系 Vol.25 No.8

This paper presents a desirable hollow shape of biaxial hollow reinforced concrete (RC) half slabs. The two-phase experimental works of the RC slabs having different types of hollows were carried out to observe the structural performances of these slabs. From the Phase I test, the shape and spacing of the hollow were determined, and then the Phase II test was performed to evaluate the flexural capacity of the slabs with the proposed hollow shape. The test results of the slabs indicated that the structural behavior and the failure modes of the hollow RC slabs were strongly influenced by hollow shapes. Though the gross sectional area of the slabs having the proposed hollow shape was much smaller than that of the solid slabs, the slabs having the proposed hollows showed sufficient flexural capacity and desirable failure mode.