• Archives of Pharmacal Research
• /
• v.27 no.12
• /
• pp.1226-1232
• /
• 2004

Extracts from seventeen seaweeds were determined for tyrosinase inhibitory activity using mushroom tyrosinase with L-tyrosine as a substrate. Only one of them, Ecklonia stolonifera OKAMURA (Laminariaceae) belonging to brown algae, showed high tyrosinase inhibitory activity. Bioassay-guided fractionation of the active ethyl acetate (EtOAc) soluble fraction from the methanolic extract of E. stolonifera, led us to the isolation of phloroglucinol derivatives [phloroglucinol (1), eckstolonol (2), eckol (3), phlorofucofuroeckol A (4), and dieckol (5)]. Compounds 1~5 were found to inhibit the oxidation of L-tyrosine catalyzed by mushroom tyrosinase with $IC_{50}$ values of 92.8, 126, 33.2, 177, and 2.16 ${\mu}g$ /mL, respectively. It was compared with those of kojic acid and arbutin, well-known tyrosinase inhibitors, with $IC_{50}$ values of 6.32 and 112 ${\mu}g$ / mL, respectively. The inhibitory kinetics analyzed from Lineweaver-Burk plots, showed compounds 1 and 2 to be competitive inhibitors with $K_i$ of $2.3{\times}10^{-4}\;and\;3.1{times}10^{-4}$ M, and compounds 3~5 to be noncompetitive inhibitors with $K_i$ of $1.9{\times}10^{-5},\;1.4{\times}10^{-3}\;and\;1.5{\times}10^{-5}$ M, respectively. This work showed that phloroglucinol derivatives, natural compounds found in brown algae, could be involved in the control of pigmentation in plants and other organisms through inhibition of tyrosinase activity using L-tyrosine as a substrate.

• Journal of Environmental Science International
• /
• v.16 no.7
• /
• pp.799-804
• /
• 2007

Oil spill caused severe effects on the marine fauna and flora due to direct contact of organisms with the oil and even in regions not directly affected by the spill. This study was conducted to understand the effects of the oil spill accidents and the use of dispersant on the red tide of Cochlodinium polykrikoides. Crude oil produced in Kuwait, bunker-C, kerosene and diesel oil, and a chemical dispersant produced in Korea, were added with a series of 10 ppb to 100 ppm in the f/2-Si medium at $20^{\circ}C$ under a photon flux from cool white fluorescent tubes of $100\;mol\;m^{-2}\;s^{-1}$ in a 14: 10 h L:D cycle for the culture of C. polykrikoides. In low concentrations of ${\leq}$ 1 ppm of examined oils no impact on the growth of C. polykrikoides was recorded, while in high concentration of ${\geq}$ 10 ppm, cell density was significantly decreased with the range of 10 to 80% in comparison with the control. The growth of C. polykrikoides after the addition of the dispersant and the mixtures combined with oils and a dispersant of ${\geq}$ 10 ppm appeared to decrease, whereas the growth of C. polykrikoides exposed to ${\leq}$ 100 ppb showed little serious impact. However, almost all the C. polykrikoides cells were died regardless of a dispersant and combined mixtures within a few days after the addition of high concentrations.

• Animal cells and systems
• /
• v.4 no.1
• /
• pp.1-7
• /
• 2000

The genus Dendronephthya, generally known as soft corals, is reported as an abundant and variable taxon. They mostly distribute in warmer waters of the Undo-Pacific Ocean region including Korea. In spite of their abundance and ecological importance as habitats of marine organisms, there are difficulties in the study of their identification and systematics because they have morphological variabilities and limited taxonomec characters. To resolve the problems, we attempted to elucidate the genetic relationships in the genus Dendronephthya by using random amplified polymorphic DNA (RAPD) analysis. This study was based on eight dendronephthian species and one Alcyoniidae species, Alcyonium gracillimum, as an outgroup. The results from all analysis suggest that they could be classified into four groups by the growth form and the anthocodial grades as follows: the first one,D. putteri and D. suensoni with the divaricate form and VI grade; the second one,D. sp.1 and D. sp.2 with the divaricate form and III or IV grade; the third one, D. gigantea and D. aurea being closer than D. spinifera with the glomerate form and III grade; the last one, D. castanea related to D. gigantea rather than D. putteri with the umbellate form and IV grade. Moreover, the divaricate form was separated from the group of the glomerate and umbellate form. At the intraspecies level, the types of the D. castanea, D. gigantea and D. spinifera were separated depending on the feature of spicules in the polyp head, and the coloration could not influence genetic variation. From this study, we can confirm that their morphological characters are compatible with the genetic variation, also RAPD analysis is a very useful method for resolving the systematic relationships of den-deonephthians.

• Ocean and Polar Research
• /
• v.43 no.4
• /
• pp.255-267
• /
• 2021

To understand the composition and community changes of benthic species by water depth (5 m, 20 m, 30 m) in the cage facilities, net substrate made of fish cages were installed at intervals of 2 months from March to September 2019, which is the main period of sessile organism recruitment. Water temperature and salinity varied in the ranges of 1~5℃ and 1~4 mg/L at 5 m from June to August, respectively, and less difference was observed according to water depth in other investigation periods. A total of 37 benthic animals were recruited, and Kamptozoa unid., Caprella scaura and Jassa slatteryi were verified during the entire study period. Mytilus galloprovincialis, a Mediterranean mussel, showed seasonality dominant only from spring to early summer (March to July). The community structure classified by temporal and spatial factors, and Bugula neritina, Kamptozoa unid., and Sertularella sp. contributed to the formation of the community. The depth of 5 m was exposed to environmental changes in water temperature and salinity temporally, so there was a seasonal variation in the composition of the sessile organism, but at depths of 20 m and 30 m, there was less significant environmental change and it showed relatively stable than 5 m.

• Journal of Microbiology and Biotechnology
• /
• v.31 no.4
• /
• pp.584-591
• /
• 2021

Marine algae (seaweed) encompass numerous groups of multicellular organisms with various shapes, sizes, and colors, and serve as important sources of natural bioactive substances. The brown alga Ecklonia cava Kjellman, an edible seaweed, contains many bioactives such as phlorotannins and fucoidans. Here, we evaluated the antioxidative, neuroprotective, and anti-apoptotic effects of E. cava extract (ECE), E. cava phlorotannin-rich extract (ECPE), and the phlorotannin dieckol on neuronal PC-12 cells. The antioxidant capacities of ECPE and ECE were 1,711.5 and 1,050.4 mg vitamin C equivalents/g in the ABTS assay and 704.0 and 474.6 mg vitamin C equivalents/g in the DPPH assay, respectively. The dieckol content of ECPE (58.99 mg/g) was approximately 60% higher than that of ECE (36.97 mg/g). Treatment of PC-12 cells with ECPE and ECE increased cell viability in a dose-dependent manner. Intracellular oxidative stress in PC-12 cells due to ECPE and ECE decreased dose-independently by up to 63% and 47%, respectively, compared with the stress control (323%). ECPE reduced the production of the pro-apoptotic proteins Bax and caspase-3 more effectively than ECE. Early and late apoptosis in PC-12 cells were more effectively decreased by ECPE than ECE treatments. From the results obtained in this study, we concluded that ECPE, which is rich in phlorotannins, including the marker compound dieckol, may be applied to the development of functional materials for improving cognition and memory.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.54 no.6
• /
• pp.989-999
• /
• 2021

The sound of finless porpoises Neophocaena asiaeorientalis was recorded with an acoustic recorder to confirm their emergence in the South Sea of South Korea in February, June, and November 2020. Sea water temperature and salinity were also measured. In addition, a sighting survey was conducted to observe the behavior of the finless porpoises and the marine environment, and the clicks of the finless porpoises were recorded every day. The results showed that they always emerged in the survey area. The finless porpoises mainly foraged, whereas some played or rested. The water temperature range of areas where the finless porpoises emerged was 7.5-23.5℃. Assuming that the number of clicks corresponds to the number of finless porpoises, the finless porpoises emerged the most during spring. The emergence decreased during winter and was the lowest during autumn. The finless porpoises emerged more during the daytime than during the nighttime in all seasons, indicating a temporal difference in the usage of the survey area. This might be due to the movement of prey organisms according to regional characteristics. A long-term survey and research on habitat use and environment is needed to manage and conserve the finless porpoises.

• Journal of Ecology and Environment
• /
• v.46 no.4
• /
• pp.304-315
• /
• 2022

Background: Filter-feeding zooplankton has limited food resources owing to their habitat. Consequently, it is crucial for them to acquire all essential compounds, such as fatty acids (FAs) and amino acids, from confined diets. To elucidate the trophic transfer of FAs to filter feeders, the primary consumers in freshwater ecosystems, we compared the FA accumulation patterns of two species of filter-feeding zooplankton, Daphnia magna and Branchinella kugenumaensis, in a laboratory experiment. Experimental neonates and nauplii preyed on a single phytoplankton species (Selenastrum capricornutum) for three days after hatching prior to diet switching. Five replicates per feeding group in each species were fed on six different types of mixed phytoplankton diet for 10 days after diet switching. Subsequently, the consumers and diets were harvested and FAs were extracted. Results: Principal component analysis showed that the FA profiles of zooplankton were well-grouped by species and diet. Although diet affects the FA profiles of consumers, they exhibit different FA accumulation patterns. D. magna had a higher 18C-ω3 content and ω3/ω6 ratio than did B. kugenumaensis. In contrast, B. kugenumaensis had higher contents of 18:1ω7 and 20:5ω3 (eicosapentaenoic acid), 22:6ω3 (docosahexaenoic acid), and a higher ratio of ∑18C monounsaturated FAs to ∑18C-ω3 polyunsaturated FAs than did D. magna. Conclusions: This study showed that two primary consumers, D. magna and B. kugenumaensis, fed the same diet had different assimilation patterns of FAs under controlled environments. Specific FA accumulation patterns in filter feeders can provide information on the transfer process of various FAs to high-trophic organisms.

• Korean Journal of Ichthyology
• /
• v.33 no.4
• /
• pp.205-216
• /
• 2021

Phylogenetic reconstruction based on one locus or a few loci can be misleading due to gene-tree/species-tree discordance. Species delimitation and intraspecific studies also often suffered from low resolution because of insufficient statistic power when few loci were used. Exon capture method is one of the most efficient way to collect genome-scale data, which can significantly augment studies that aimed to investigate patterns and histories of organisms at both intraspecific and high level. Here, I showed the advancement of shifting from single-gene method to genomic approach and the benefit of applying exon capture method comparing to alternative genomic techniques. Then, I explained the principle of exon capture method as well as providing detailed recommendations for applying this method. Finally, I demonstrated exon capture method using two applications and discussed future perspectives of this technology.

• Journal of dental hygiene science
• /
• v.22 no.4
• /
• pp.241-248
• /
• 2022

Background: Plastic waste generates pollutants in the process of incineration or landfilling, and accumulates in water or marine organisms, causing adverse effects on the environment and the human body. Recently, various eco-friendly oral hygiene products (Eco-OHPs) such as bamboo toothbrushes and biodegradable plastic toothbrushes have been developed. Therefore, this study aimed to investigate the current level of awareness and purchasing status of eco-OHPs among adults who are interested in eco-friendly products. Methods: This study included adults aged >19 years who regularly visited eco-friendly shops and online sites; the online survey links were distributed during their visits to eco-friendly Internet cafés and companies. Of the 22 questions, seven assessed the participants' general characteristics, three assessed the general oral hygiene care products used, six assessed the level of awareness of Eco-OHPs, and six assessed the purchasing status of Eco-OHPs. Frequency analysis, chi-square test, and regression analysis were performed using SPSS software. Results: Among the respondents, 108 (51.4%) were aware of Eco-OHPs, and 79 (37.6%) had experience purchasing Eco-OHPs. The most common reason for not purchasing was the lack of information about related brands or products (74, 56.5%). The most common platform used in obtaining information was the Internet (general: 31.5%, eco-friendly: 46.3%), such as Social Network Service, Internet cafes, and blogs. The experience in purchasing Eco-OHPs was affected by whether the respondents recognized the possibility of contributing to environmental preservation, availability of vendors, product safety, and the number of eco-friendly products purchased. Conclusion: In order to expand the use of Eco-OHPs, various efforts such as promotion of eco-friendly characteristics, determination of related vendors, reliable analysis of product safety, and expansion of product experience opportunities are required.