• 환경생물
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• 제38권2호
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• pp.278-288
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• 2020

Rhodomonas salina is a phototrophic marine flagellate. We examined the ultrastructure of R. salina with particular attention to the flagellar apparatus by transmission electron microscopy and compared it with that of other cryptomonads reported previously. The major components of the flagellar apparatus in R. salina were a keeled rhizostyle (Rhs), a striated fibrous root(SR), a SR-associated microtubular root (SRm), a mitochondrion-associated lamella (ML), and three types of microtubular roots (9r, 4r, and 2r). The keeled Rhs originated near the proximal end of the dorsal basal body, passed near the nucleus and dissociated at the posterior end of the cell. The SR and SRm originated between two basal bodies and laterally extended to the right side of the cell. The ML originated between two basal bodies and extended to the left side of the cell. The 9r originated between the ventral basal body and the Rhs and extended toward the anterior dorsal lobe of the cell. The 4r originated near the 9r and extended toward the dorsal lobe with the 2r, which originated between two basal bodies. Here, the flagellar apparatus in R. salina is described, and the ultrastructure of the flagellar apparatus is compared among cryptomonad species.

• Journal of Microbiology and Biotechnology
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• 제23권3호
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• pp.289-296
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• 2013

Cryptomonads are unicellular, biflagellate algae. Generally, cryptomonad cells cannot be preserved well because of their fragile nature, and an improved methodology should be developed to identify cryptomonads from natural habitats. In this study, we tried using several cytological fixatives, including glutaraldehyde, formaldehyde, and their combinations to preserve field samples collected from various waters, and the currently used fixative, Lugol's solution was tested for comparison. Results showed that among the fixatives tested, glutaraldehyde preserved the samples best, and the optimal concentration of glutaraldehyde was 2%. The cell morphology was well preserved by glutaraldehyde. Cells kept their original color, volume, and shape, and important taxonomic features such as furrow/gullet complex, ejectosomes, as well as flagella could be observed clearly, whereas these organelles frequently disappeared in Lugol's solution preserved samples. The osmotic adjustments and buffers tested could not preserve cell density significantly higher. Statistical calculation showed the cell density in the samples preserved by 2% glutaraldehyde remained stable after 43 days of the fixation procedure. In addition, DNA was extracted from glutaraldehyde preserved samples by grinding with liquid nitrogen and the 18S rDNA sequence was amplified by PCR. The sequence was virtually identical to the reference sequence, and phylogenetic analyses showed very close relationship between it and sequences from the same organism. To sum up, the present study demonstrated that 2% unbuffered glutaraldehyde, without osmotic adjustments, can preserve cryptomonads cells for identification, in terms of both light microscopy and phylogenetic analyses based on DNA sequences.

• ALGAE
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• 제28권4호
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• pp.331-341
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• 2013

Rhinomonas reticulata var. atrorosea G. Novarino is a photosynthetic marine flagellate that is known to have typical characteristics of cryptomonads. We examined the flagellar apparatus of R. reticulata var. atrorosea by transmission electron microscopy. The major components of the flagellar apparatus of R. reticulata var. atrorosea consisted of four types of microtubular roots (1r, 2r, 3r, and mr), a non-keeled rhizostyle (Rhs), mitochondrion-associated lamella (ML), two connections between basal bodies, a striated fibrous root (SR) and a striated fiber-associated microtubular root (SRm). Four types of microtubular roots originated near the ventral basal body and extended toward the left side of the basal bodies. The non-keeled Rhs originated at the Rhs-associated striated fiber, which was located between two basal bodies and extended into the middle of the cell. The ML was a plate-like fibrous structure associated with mitochondria and originating from a Rhs-associated fiber. It split into two parts and extended toward the dorsal-posterior of the cell to a mitochondrion. The SR and SRm extended parallel to the anterior lobe of the cell. The overall configuration of the flagellar apparatus in R. reticulata var. atrorosea was similar to the previously reported descriptions of those of Cryptomonas paramecium, C. pyrenoidifera, C. ovata, Hanusia phi, Guillardia theta, and Proteomonas sulcata. However, the flagellar apparatus system of R. reticulata var. atrorosea was more complex than those of other cryptomonad species due to the presence of an additional microtubular root and other distinctive features, such as a rhizostyle-associated striated fiber and large ML.

• 생태와환경
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• 제35권3호통권99호
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• pp.187-197
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• 2002

아산호에서 1997년 3월부터 1997년 11월까지 6회에 걸쳐 식물플랑크톤 군집구조를 파악하기 위한 연구를 수행하였다. 19개 정점에서 관찰된 식물플랑크톤 분류군은 총 204종군으로, 각 분류군별 출현비는 녹조류 51%, 규조류 29%, cyanobacteria 12%, 와편모조류가 2%, 유글레나류 4%, 기타 편모조류가 2% 이었다. 식물플랑크톤의 현존량은 741ce11s/m떼서 613,066ce11s/ml의 범위로 매우 높은 수준으로 나타났다. 현존량은 7월에 가장 높았고 9월, 6월, 3월, 11월, 5월 순으로 나타났다. 계절에 관계없이 지속적으로 녹조상태인 것으로 판단되며, 녹조원인생물은 Micractium pusillum, Stephandiscus hantzschii, Dictyospharium pulchellum, cryptomonad (> 20 ${\mu}$, Microcystis aeruginosa, Oscillatoria tenuis, Oscillatoria sp., Aphanocapsa sp. Euglena sp., Volvox aureus 이었다. 여름철에 cyanobacteria에 의한 녹조현상이 현저하였다. 식물플랑크톤의 종다양성은 0.13${\sim}$의 범위로 시${\cdot}$공간적으로 차이가 매우 컸다. 집괴 분석한 결과 전반적으로 아산호 하류수역과 상류수역 투 개의 수역으로 구분이 되었다.

• ALGAE
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• 제20권3호
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• pp.197-205
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• 2005

Temporal variability in lake phytoplankton is controlled by a complex between hydrological and chemical factors, and biological interactions. We explored annual change of phytoplankton in Lake Daecheong, using phytoplankton analysis data from 1997 to 2002 (except 2000). The standing crop of phytoplankton was ranged from 3.5 x 10 to 1.5 x 106 cells mL$^{-1}$ and the highest mean value was at site 1. The class composition ratios of phytoplankton standing crop were divided into three classes. From January to March, diatoms showed a dominance (68.1-77.7%). From April to June, diatoms were mixed with cryptomonad etc. or blue-green algae. From July to October, blue-green algae showed a dominance (54.7-84.0%). In the case of green algae, the class composition ratios were below 10%. But green algae appeared all the year round.

• 환경생물
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• 제39권4호
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• pp.435-444
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• 2021

The genus Chroomonas is a group of blue-green colored cryptomonads. This study describes two freshwater Chroomonas species for the first time in South Korea: Chroomonas nordstedtii Hansgirg and Chroomonas coerulea (Geitler) Skuja. We examined the morphology and ultrastructure of these species by light microscopy, scanning electron microscopy, and transmission electron microscopy. These two Chroomonas species were blue-green colored and ovate to oval-shaped. Chroomonas nordstedtii was characterized by two Maupas ovals with hexagonal periplast plates, whereas C. coerulea was characterized by one eyespot with rectangular periplast plates. A molecular phylogeny with data from nuclear SSU rRNA and chloroplast rbcL genes revealed that Korean C. nordstedtii formed a distinct clade with NIES-708, NIES-1004 from Japan, and UTEX 2779 from Colorado, USA, while C. coerulea formed a clade with ACOI 1366 from Portugal.

• ALGAE
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• 제31권2호
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• pp.117-128
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• 2016

Cryptomonas curvata Ehrenberg is a photosynthetic freshwater flagellate and the type species of the genus Cryptomonas. We examined the flagellar apparatus of cryptomorphic C. curvata by transmission electron microscopy. The major components of the flagellar apparatus are the non-keeled rhizostyle (Rhs), striated fibrous root (SR), striated fiber-associated microtubular root (SRm), mitochondrion-associated lamella (ML), and two types of microtubular roots (3r and 2r). The non-keeled Rhs originate at the ventral basal body and consist of two types of microtubule bands extending together into the middle of the cell. The SR and SRm extend parallel to the left side of the cell. The ML originates from the ventral basal body and is a plate-like fibrous structure associated with mitochondria. The 3r extends from the dorsal basal body toward the dorsal anterior of the cell. The 2r originates between the two basal bodies and extends shortly to the left of the cell. The overall configuration of the flagellar apparatus is most similar to that previously reported for C. pyrenoidifera. These results demonstrate that the features of the flagellar apparatus are useful for distinguishing closely related species and inferring phylogenetic relationships among taxa.

• Journal of Ecology and Environment
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• 제29권5호
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• pp.433-438
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• 2006

To elucidate the mechanisms by which algal food quality affect Daphnia growths, we measured carbon incorporation rates and respiration rates of Daphnia magna with Cryptomonad Rhodomonas minuta, green algae Scenedesmus acutus and cyanobacteria Synechococcus sp. with varying physiological states as food. Carbon assimilation rates were high with R. minuta and S. acutus and low with Synechococcus sp. showing a similar pattern to the growth rate pattern. There was no clear difference among respiration rates of three algal species. Carbon assimilation rates and respiration rates of D. magna appeared to be independent on Molar C:P ratios in algal foods. Carbon growth efficiencies (incorporated carbon per assimilated carbon amount) were lower when D. magna fed with Synechococcus sp. than fed with R. minuta or S. acutus. Analysis of variance results show that carbon assimilation rates which were sum of incorporation and respiration rates and carbon growth efficiencies were only dependant on species affiliation. Overall, our results showed that algal species with varying ${\omega}3$ polyunsaturated fatty acid content led different carbon incorporation rates and overall carbon assimilation rates of D. magna.

• 한국해양학회지
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• 제18권2호
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• pp.91-103
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• 1983

1981년 9월에 한국동남해역의 연안역, 대륙붕역 및 대륙사연역에 이르는 각 수역에서 수심 별로 채집된 식물 플랑크톤의 정성 및 정량시료를 분석하였다. 본 연구에서는 185종류의 식물 플랑크톤을 동정하였으며, 이는 규조류 124종류, 쌍편모조류 56종류, 규질편모류 3종류 및 각 1종류씩의 갈색편모조류와 유글레나류 로 구성되어 있다. 식물 플랑크톤 군집을 분석한 결과 연구해역은 2개의 식생역 으로 구분됨을 알게 되었고, 해수의 물리적 특성에 의하여 이들 식생역의 범위가 크게 좌우됨이 밝혀졌다. 동남 연안역의 경우 식생은 매우 풍부하였으며 소형 규조류와 미세 편모류가 주종이었고 연구 해역의 북부 수역에서는 여러 종류의 규류조 및 쌍편모조류가 다량 출현하였다. 식물 플랑크톤 현존량을 해수의 물리적 특성, 식물 플랑크톤의 종조성과 비교하였다. 연구 해역의 북부 수역에서는 식물 플랑크톤의 현존량분포에 있어서 대마난류수와 북한한류 계수의 혼합이 특히 중요함을 알게 되었다.

• 한국환경과학회지
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• 제9권2호
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• pp.115-123
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• 2000

The dynamics of water quality and phytoplankton population had examined by monthly sampling from the upper to the lower part of watergate in an artificial Shihwa Reservoir in which situated near newly cities and incustrial complex on the west coast of Korea from January 1997 to December 1998. Among environmental factors, yearly average concentration of chl-a, TN and TP seemed to eutrophic or hypertrophic conditions that ranged 146.4~245.8 $\mu\textrm{g}$/$\ell$, 1.6~2.7 mg N/$\ell$, 258~448 $\mu\textrm{g}$ P/$\ell$, 26.9~80.7 $\mu\textrm{g}$/$\ell$, 1.0~2.4 mgN/$\ell$ and 74~239 $\mu\textrm{g}$P/$\ell$ respectively. Water quality was extremely deteriorated to consistently accumulation into inner reservoir by load of pollutants from autochthonous and allochthonous until early July 1997 after embankment. Water pollution of Shihwa Reservoir was remarkble on the biological condition with largely persistent bloom of phytoplankton and increase rate of standing crops was 2.4/yr. The development trend of phytoplankton in water ecosystem were closely related to increse and decrease of physico-chemical factors and those scale seemed to control by nutrient contents. Inflow of seawater into reservoir to object of repair of water quality. As to see dominant species, composition of those composed to mostly freshwater algae before inflow of seawater such as Selenastrum capricornutum of green algae, cyclotella atomus, C. meneghiniana of diatom and Microcystis spp. of blue-green algae and the other hand brackish algae were dominated after inflow of seawater such as Chaetoceros dicipiens, Skeletonema costatum of diatom, Dinophysis acuminata, Gymnodinium mikimotoi, G. sanguineum, Gyrodinium spirale, Prorocentrum minmum of dinoflagellate and Eutreptiella gymnastica of euglenoid. Moreover, small flagellates including Chroomonas spp. of cryptomonad were abundant throughout the year. The cause of water deterioration during fill of the freshwater were complexly supported with extra and intra parameters. The variation pattern of phytoplankton were related to water temperature and salinity by inflow of seawater based to plentiful nutrients. The dynamics of phytoplankton were assessed to ecosystem that clearly condition of dominant by unique or a few angel species seasonally.