• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.8
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• pp.4086-4092
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• 2013

Mycosporine-like amino acids (MAAs) are UV-absorbing substances, and diverse marine organisms have the evolved the capacity to diminished the direct and indirect damaging effects of environmental ultraviolet radiation by synthesis and accumulation of MAAs. In this study, we manufactured a radiofrequency (RF) generation device and applied to microalgal culture. $0.35{\pm}0.05$ mHz of RF was supplied to culture vessel for Chlamydomonas sp. and samples were harvested at the designated time intervals (1, 0.5, 1 and 2 hr). MAAs biosynthetic genes, dehydroquinate synthase homolog (DHQS-like) and nonribosomal peptide synthetase homolog (NRPS-like), were cloned from Chlamydomonas sp. and their gene expressions under the RF exposure were analyzed using qRT-PCR. DHQS-like and NRPS-like gene expressions of Chlamydomonas sp. exposed to RF were increased 1.46 and 1.19 fold at 1 hr, respectively. These results means that DHQS-like and NRPS-like genes can be good biomarker candidates for diagnosis of MAAs biosynthesis in the Chlamydomonas sp.

• Journal of Microbiology and Biotechnology
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• v.25 no.5
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• pp.723-731
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• 2015

Microalgae hold promise as producers of sustainable biomass for the production of biofuels and other biomaterials. However, the selection of strains with efficient and robust production of desirable resources remains challenging. In this study, we isolated a green microalga from Korea and analyzed its morphological, molecular, and biochemical characteristics. Microscopic and phylogenetic analyses demonstrated that the isolate could be classified into the genus Chlamydomonas, and we designated the isolate Chlamydomonas sp. KIOST -1. Compositions of protein, lipid, and carbohydrate in the microalgal cells were estimated to be 58.8 ± 0.2%, 22.7 ± 1.2%, and 18.5 ± 1.0%, respectively. Similar to other microalgae belonging to Chlorophyceae, the dominant amino acid and monosaccharide in Chlamydomonas sp. KIOST-1 were glutamic acid and glucose. On the other hand, the proportions of saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids clearly differed from other species in the genus Chlamydomonas, and monounsaturated fatty acids accounted for a large portion (41.3%) of the total fatty acids in the isolate. Based on these results, Chlamydomonas sp. KIOST-1 has advantageous characteristics for biomass production.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.8
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• pp.5393-5399
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• 2014

To examine the effects of a mycosporine-like amino acids (MAAs) mixture from microalgae, Chlamydomonas sp, on the anti-wrinkle activities, the expression levels of genes that are associated with skin aging, including type I procollagen, elastin and involucrin, were analyzed. Asterina 330+palythine (A+P) and shinorine+palythine (S+P) mixtures were purified from Chlamydomonas sp using the following steps: 80% methanolic extraction, column purification, and HPLC analysis. As a result of the MTT assay, A+P and S+P did not induce cellular cytotoxicity with up to 0.1 mg/mL of both MAAs. In addition, the treatment of UV-exposed fibroblasts with A+P (0.05 mg/mL) and S+P (0.01 mg/mL) increased the levels of the PCOLCE mRNAs by 2.7 and 3.6 fold compared to the control group, respectively, The levels of elastin gene expression were elevated 5.59 and 3.1 fold in the A+P and S+P treated (0.01 mg/mL) cells, respectively. In particular, at a concentration of 0.01 mg /mL, the A+P and S+P expression levels of Involucrin mRNAs were increased 3.5 and 2.5 fold in the UV-exposed cells compared to the control, respectively. In conclusion, the MAAs derived from Chlamydomonas sp can be utilized as functional cosmetic materials with anti-wrinkle effects on the skin.

• Korean Journal of Organic Agriculture
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• v.22 no.4
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• pp.743-760
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• 2014

This study aimed to isolate and identify freshwater algae from the organic agricultural ecosystems and investigate its biological characteristics to study the possibility of utilizing a biomass freshwater algae in organic farming. In the survey area, average water temperature was $12.4{\sim}28.2^{\circ}C$ and the pH ranges were from 6.1 to 8.5. The solid culture method is more suitable than liquid culture method for isolation of freshwater algae with lower contamination level and higher isolation frequency. A total of 115 strains were isolated from six freshwater algae habitats in nine regions in Korea. BGMM (BG11 Modified Medium) amended with NaNO3 and $KNO_3$ as a nitrogen, and $Na_2CO_3$ as carbon source was designed to isolate and culture freshwater algae. Absorbance of freshwater algae culture has increased dramatically to four days and decreased after eight days after inoculation. CHK008 of the seven isolates showed the highest absorbance in seven days after culturing in BGMM. The optimal pH of BGMM for culturing freshwater algae was pH 6-7. As light intensity increased, growth of freshwater algae increased. Among the five kinds of carbon sources, glucose and galactose promoted good growth of freshwater algae in BGMM. The colony color of purified 16 green algae isolates showed a separation of green, dark and light green, and of them, eleven algae strains showed a strong fluorescent light under fluorescence microscopy. Cell size of the green algae showed a wide range of variation depending on the species. General morphology of the green algae strains was spherical. Chlamydomonas sp. was elliptical, and Chlorella sorokiniana was ellipsoidal and cylindrical. All strains of the green algae except for Chlamydomonas sp. did not have flagella. One isolate of Chlamydomonas sp. and five isolates of C. sorokiniana secreted mucus. Sixteen isolates of 16 green algae were identified as two family and six species, Chlorella vulgalis, C. sorokiniana, C. pyrenoidosa, C. kessleri, C. emersonii, and Chlamydomonas sp. based on their morphological characteristics.

• Korean Journal of Environmental Biology
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• v.18 no.1
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• pp.95-104
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• 2000

In order to elucidate chatracteristics of water quality and seasonal dynamics of phytoplankton community in Kyungpo lake, the weekly variation of algal population and 11 environmental factors were investigated from March 1998 to February 1999. A total 121 species of phytoplankton belonged to 57 genera, 4 genera 7 species of the Euglenophyceae, 1 genera 2 species of the Chrysophyceae, 2 genera 3 species of the Cryptophyceae, 1 genera 1 species of the Dinophyceae, 6 genera 9 species of the Cyanophyceae, 28 genera 78 species of the Bacillario-phyceae and 15 genera 21 species of the Chlorophyceae, was identified. Cryptomonas sp., Chamydomonas sp., Nitzschia frustulum, Oscillatoria sp., Lyngbya sp, and Dictyosphaerium pulchellum occurred successively as dominant phytoplankton species from March 1998 to February 1999. Density of phytoplankton cell number showed the peak in early April when Chlamydomoas sp. was dominated. The diversity index of phytoplankton community showed low values in the dominating period of Cryptomonas sp. and Chlamydomonas sp. The concentration of chlorophyll a fluctuated between 1.09 and 107.7$\mu\textrm{g}$ㆍ1$^{-1}$. Water temperature, salinity, DO, conduc tivity and SS were ranged 0.5-27.8$^{\circ}C$, 2.8-25.2 ppt, 4.62-19.21 mgO$_2$ㆍ1$^{-1}$, 5.33-34.76 mS/cm and 0.017-0.184 mgㆍ1$^{-1}$, respectively. Annual means of Secchi disc transparency was 36cm and thai of pH value was 8.5. The concentrations of PO$_4$-P was ranged 0.0012-0.077 mgㆍ1$^{-1}$ , and showed high value from August to October. The concentrations of NO$_2$-N, NO$_3$-N and NH$_4$-N was ranged 0.0011-0.1 mgㆍ1$^{-1}$, 0.074-3.33mgㆍ1$^{-1}$ and 0.0024-0.259 mgㆍ1$^{-1}$, respectively. Among environmental factors, water temperature was negatively correlated with DO, salinity and conductivity, DO was positively correlated with salinity and conductivity. Chlorophyll a, one of the indicies of eutropication in lake, was negatively correlated with NH$_4$-N. The cell density of Cryptomonas sp., which was the most dominant species in this lake, was negatively correlated with transparency. [Kyoungpo lake, Phytoplankton, Cryptomonas sp. , Chlamydomonas sp., Seasonal variation].

• Natural Product Sciences
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• v.26 no.1
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• pp.59-63
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• 2020

This study focused on investigation of the immunosuppressive inhibitory effect through determination of IL-2 production of nine compounds (1 - 9) isolated from Chlamydomonas sp. KSF108. Among them, compounds 1, 5, and 6 displayed moderately inhibitory effects on IL-2 production at a concentration of 100 µM. In addition, the related ones including cytotoxic, anti-inflammatory, and anti-oxidant activities were also elucidated. 6 further displayed cytotoxic activity against the MCF-7 cell line, with an IC₅₀ value of 17.2 µM and 4, 6 - 7, and 9 possessed significant DPPH radical scavenging activity, with IC₅₀ values ranging from 3.1 to 4.4 µM. To the best of our knowledge, this is the first report on the bioactivity of isolated chemical constituents from the genus Chlamydomonas. Compounds 1 and 5 investigated for the first time in the activity of immunosuppressivity and 6 may come to serve as the most important marker in broad-spectrum activities of the secondary metabolites identified from C. sp. KSF108.

• Korean Journal of Ecology and Environment
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• v.35 no.2 s.98
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• pp.103-110
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• 2002

Seasonal changes of the phytoplankton community was investigated from July 2000 to April 2001 at the river bed lake, Jangjwa Lake in the Imjin River, which appeared to be the most natural condition. A total of phytoplankton were composed of 112 taxa, belonging to 5 divisions,83 species, 10 varieties,1 variety-form, 1 form and 17 unidentified species. Of those, the green algae and the diatoms were present during the investigation periods more frequently then the other taxa. The phytoplantton standing crops varied from $2,943{\times}10^3\;cells/l$ on April 2001 to $5,742{\times}10^3\;cells/l$ on January 2001. The phytoplankton standing crops had a continuous high value over $3,000{\times}10^3\;cells/l$ during the investigated periods and showed the highest value during winter period. The major dominant species were Aulacoseira granulata, Chlamydomonas nivalis v. kobayasii, Dinobryon sertularia, Mougeotia so. and Uroglenopsis americana. Among those, Chlamydomonas nivalis v. kobayasii was a major dominant species during winter period.

• Journal of Korean Society of Water and Wastewater
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• v.35 no.1
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• pp.63-69
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• 2021

Microalgae are primary producers of aquatic ecosystems, securing biodiversity and health of the ecosystem and contributing to reducing the impact of climate change through carbon dioxide fixation. Also, they are useful biomass that can be used as biological resources for producing valuable industrial products. However, harvesting process, which is the separation of microalgal biomass from mixed liquor, is an important bottleneck in use of valorization of microalgae as a bioresource accounting for 20 to 30% of the total production cost. This study investigates the applicability of sewage sludge-derived extracellular polymeric substance (EPS) as bioflucculant for harvesting microalgae. We compared the flocculation characteristics of microalgae using EPSs extracted from sewage sludge by three methods. The flocculation efficiency of microalgae is closely related to the carbohydrate and protein concentrations of EPS. Heat-extracted EPS contains the highest carbohydrate and protein concentrations and can be a best-suited bioflocculant for microalgae recovery with 87.2% flocculation efficiency. Injection of bioflocculant improved the flocculation efficiency of all three different algal strains, Chlorella Vulgaris, Chlamydomonas Asymmetrica, Scenedesmus sp., however the improvement was more significant when it was used for flocculation of Chlamydomonas Asymmetrica with flagella.

• Korean Journal of Environmental Biology
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• v.24 no.3
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• pp.221-229
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• 2006

The effects of ultrasonication on phytoplankton were investigated in two ponds in which physicochemical and biological water quality was similar, one as a treatment and the other as a control. The samples were collected from August 18 to September 30 in 2003. Traditional morphological analysis showed that Bacillariophyceae dominated phytoplankton community in both ponds. The abundance of Cyanophyceae was lower in the phytoplankton community of the sonicated pond than that of control pond. We used DGGE (denaturing gradient gel electrophoresis) to analyze the diversity and change of phytoplankton community in two ponds. The DGGE banding patterns of 16S rRNA gene and sequence analysis demonstrated that Oscillatoria acuminata and CFB (Cytophaga-Flavobacterium-Bacteroides) group bacterium appeared in the treated pond, and the control pond was dominated by Synechococcus sp. and Aphanizomenon flos-aquae. Especially, Pseudanabaena sp. dominated during the ultrasonic cessation in the treated pond. The DGGE profiles of 18S rRNA gene and sequence analysis showed that the treated pond was dominated by Chlamydomonas reinhardtii and the control pond by C. reinhardtii and Pteromonas protracta. In conclusion, the ultrasonication affected the reduced growth of cyanobacteria, particularly Pseudanabaena.

• Journal of fish pathology
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• v.8 no.2
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• pp.157-164
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• 1995

In order to examine the effects of $O_2$ saturation and pH on gas-bubble disease of blue crab, portunus trituberculatus, zoeal larvae were reared under 5 different concentrations (6.0, 4.0, 3.1, 2.2, and 0.7million cell/cc) of Chlamydomones sp. under natural light for 4days. Observed pH and $O_2$ saturation in the rearing chamber increased drastically from 12 to 18 o'clock with the increasing of Chlamydomones sp. concentrations, but rapidly decreased from 2 to 6 o'clock in the rearing chamber. Gas-bubble disease of zoeal larvae was observed 4hours after starting of experiment at the pH 8.5 and 118% $O_2$ saturated conditions in rearing chamber during the day, and recovered rapidly with the decreasing of pH and $O_2$ saturation at night. Thus, gas-bubble disease of zoeal larvae was repeated with the increased pH($\geq$8.5) and $O_2$ saturation ($\geq$118%) almost every days. Mortality of zoeal larvae was observed when pH and $O_2$ saturations were reached 8.5 and 118% levels respectively, and deteriorated with the increasing of water temperature, pH and $O_2$ saturation.