• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.7
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• pp.4416-4422
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• 2014

In the present study, mycosporine-like amino acids (MAAs)were extracted from in Chlamydomonas hedleyi, and their function was investigated regarding to protective capacity against UV radiation and a possibility to be developed into functional suncream including MAAs by using natural compounds. In particulr, we assessed UV protective ability and anti-inflammation of shinorine in human skin cells. As a result, shinorine can protect the skin against damage by the absorption of energy from UV radiation and functions as an anti-wrinkling substrate through a increase of collagen synthesis. These data suggest that shinorine can be utilized not only as a substrate to protect UV radiation, but anti-aging material in cosmetic products.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.7
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• pp.3589-3595
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• 2013

Changes of phenolics, antioxidant activities and fatty acid contents were determined in the mangrove plant exposed to Cu, Ni and Cd. Propagules of Rhizophora mangle were cultured for 12 weeks under the Cu (0.01 and 1 ppm), Ni (0.1 and 10 oom) and Cd (0.1 and 10 ppm) stresses. In comparison with control, morphological changes of mangrove root were not observed in 12 weeks. Significant changes of phenolics were not detected and antioxidant activities were dramatically increased in the metal-treated mangroves. Fatty acid, C14:1, C15:1 and C18:3n-6, contents were changed in the all of tested propagules. These results shows that DPPH radical scavenging assay and determination of fatty acid contents could be useful biomarkers for diagnosing responses of mangrove plant under heavy metal stress.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.11
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• pp.5615-5622
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• 2012

Seasonal distributions of the viral abundance and physicochemical parameters were analyzed at three different regions in Gwangyang Bay. Morphological structure of marine virus was observed using transmission electron microscopy. Most of marine virus had bacteriophage-like structure, but some were similar with eukaryotic microalgal virus, Ectocarpus siliculosus virus (EsV). Viral abundance at Group 1 (closed eutrophic region) was higher than viral abundances at Group 2 (closed oligotrophic region) and Group 3 (open oligotrophic region). Seasonal abundances of marine virus at Group 1 were dynamically changed. The viral density was variably changed from maximum $7.33{\times}10^8ml^{-1}$ in August to minimum $0.3{\times}10^8ml^{-1}$ in December and maintained middle value in spring and autumn. The concentration of nitrogen and phosphate sources was correlated with viral abundance. Particularly, seasonal change of dissolved oxygen concentration was opposite to the variation of viral abundance. These results showed that viral abundances were closely related with fluctuation of marine physicochemical environment in Gwangyang bay.

• Journal of Life Science
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• v.30 no.1
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• pp.26-31
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• 2020

Heterosigma akashiwo is a globally distributed raphidophyte that forms blooms and causes significant losses to the aquaculture industry in many coastal countries. The development of a fast and sensitive detection method is therefore required to facilitate the appropriate warning of harmful algal blooms. In this study, a nuclease protection integrated with sandwich hybridization (NPA-SH) assay was developed to both qualitatively and quantitatively detect H. akashiwo. The NPA, capture and signal probes were designed by nucleotide sequencing of H. akashiwo. The applicability of NPA-SH was evaluated using cultured H. akashiwo cells and field samples collected at Goseong Bay, Korea. The results show that this method has good applicability and effectiveness in analyzing cultured cells and field samples. A linear regression equation for the quantitative analysis of H. akashiwo was obtained, and the lower detection limit of the assay was 1×10⁴ cells/ml. There was no statistically significant difference in the results of H. akashiwo quantitation using NPA-SH compared to those obtained using a microscope. These results indicate that NPA-SH can be a good alternative to the traditional microscopic method used to monitor H. akashiwo.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.7
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• pp.3267-3274
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• 2012

371 strains of marine bacteria were isolated from Gwangyang bay in Korea. The dominant species were identified as Pseudomonas aeruginosa, Aeromonas hydrophila, P. fluorescens, P. paucimobilis, Chryseomonas luteola and P. vescularis. To screen marine bacteria capable of removing nutrients and organics, marine bacteria was inoculated in 10 mL of marine broth 2216 (DIFCO) with $NH_3-N$ (100 mg/L), ${NO_3}^{-}-N$ (100 mg/L), and ${PO_4}^{-3}-P$ (10 mg/L) with 1.0% (v/v), and incubated for 12 h. Results from the screening test, showed that the removal efficiencies for $COD_{Cr}$, ammonia niterogen, nitrate nitrogen, and phosphate were over 25% for 16 strains, 15% for 9 strains, 50% for 63 strains, and 15% for 80 strains, respectively. Aeromonas hydrophila, Chryseomonas indologenes, Pseudomonas diminuta, Vibrio parahaemolyticus were selected for nutrients removal experiments. For the batch test, 4 species of marine bacteria were inoculated in modified marine broth containing with nutrients($COD_{Cr}$ 250 mg/L, $NH_3-N$ 40 mg/L, ${NO_3}^{-}-N$ 40 mg/L, ${PO_4}^{3-}-P$ 10 mg/L, respectively), incubated for 10 hr and the removal efficiencies were measured.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.12
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• pp.6196-6202
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• 2012

Oligo-alginate derivatives were extracted from brown algae and its antimicroalgal effects and reaction mechanism were investigated. Oligo-alginate derivatives were produced from sequential hydrolysis of high molecular weight alginate by treatment of 2 N HCl and 1% $H_2O_2$. Antimicroalgal activity of extracts was proportional to reaction time and activity was highest at 4 hrs. When oligo-alginate derivatives were treated to Akashiwo sanguinea and Cochlodinium polykrikoides, mobilities of cells were ceased. A. sanguinea cells were crushed and plasmolysis was induced in C. polykrikoides cells. To investigate the action mechanism of oligo-alginate derivatives, changes of intracellular (pHi) and extracellular pH (pHe) were determined in the microalgal cells exposed to 0.05% of oligo-alginate derivatives. pHi was decreased about 0.3 unit and pHe was increased about 0.9 unit. These results suggested that change of membrane potential by oligo-alginate derivatives could led to microalgal cell death.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.9
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• pp.5885-5892
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• 2014

Mangrove plants serve as a sink of heavy metals and contain phenolic compounds at a high level. Therefore, with mangrove plants, recent studies to develop phytoremediation and natural antioxidants have been conducted in the commercial and academic fields. In the present study, six mangroves in Weno Island of Micronesia were investigated for their phylogenetic relationship and antioxidant activities. First, to determine the phylogenetic relationship among them, rbcL (large subunit of ribulose-bisphosphate carboxylase), one of the chloroplast genes, was used as a molecular marker. According to the data, Xylocarpus, Sonneratia and Rhizophora showed close similarity but not Excoecaria. The levels of phenolic compounds in the bark were abundant in R. apiculata and X. granatum, accounting for 1.10 mM/mg, while R. stylosa and S. alba contained the low amounts, representing 0.73 mM/mg and 0.72 mM/mg, respectively (p<0.05). In addition, bark extracts from R. apiculata, X. granatum, X. moluccensis, and E. agallocha had high antioxidant activities through the DPPH radical scavenging activity and ABTS analysis, whereas S. alba showed the lowest activities. These results suggest that the bark of R. apiculata can be used as a good source for the development of natural antioxidants.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.6
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• pp.3799-3804
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• 2014

In sea water, microalgae are exposed to a range of critical environmental conditions. Microalgae are protected from UV-A radiation due to the presence of mycosporine like amino acids(MAAs). Owing to the UV-A absorption properties of MAAs, they are used widely as a UV protecting ingredient in cosmetics. Therefore, there is a need to increase the production yield of MAAs. This study investigated the production yield of MAAs in transformed microalgae by radiofrequency(RF) exposure. Initially, the Glut-1 gene was transformed to Chlamydomonas hedleyi microalgae as a glucose transporter. The biomass was enhanced after Glut-1 gene transformation. In addition, the MAAs production yield was increased during large scale production in bioreactors due to the RF treatment. Therefore, purified extracts of MAAs can be used as a sun block material in the cosmetic industrial field.

• 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 the Korea Academia-Industrial cooperation Society
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• v.14 no.6
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• pp.3081-3088
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• 2013

Phenolic contents and antioxidant activities were determined in the water and ethanol extracts from six species of edible seaweeds, Phaeophyceae (Laminaria japonica, Hizikia fusiformis and Undaria pinnatifida), Rhodophyceae (Porphyra tenera and Gracilaria verrucosa) and Chlorophyceae (Ulva lactuca). The highest extraction yield was observed in water extract (pH 8.0) of G. verrucosa (44.23 %) and phenolic content was the highest in ethanolic (75 %) extract of H. fusiformis (52.82 ${\mu}g/mg$). 25 % ethanolic extract from U. lactuca was found to have the highest DPPH radicals scavenging activity(19.29 %) and superoxide anion scavenging activitiy was higher in water extract (pH 8.0) from H. fusiformis (81.20 %) than that other seaweeds. Phenolic contents were strongly correlated with antioxidant activity in the six edible seaweeds extracts ($R^2$=0.852). Taken together, these results indicate that H fusiformis may be a excellent source for development of natural antioxidants.