• Korean Journal of Plant Resources
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• v.34 no.6
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• pp.510-516
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• 2021

Whitening agents derived from natural sources which do not have side effects are sought after. Schizophragma hydrangeoides is an edible plant that grows wild on Jeju Island. We aimed to determine whether S. hydrangeoides extracts show anti-melanogenic activity. Here, we found that 70% ethanol extracts of S. hydrangeoides leaf suppressed α-melanocyte-stimulating hormone-induced melanogenesis in B16F10 mouse melanoma cells. This activity of anti-melanogenesis in B16F10 cells were investigated by determining melanin content and tyrosinase activity, and by performing western blotting. The 70% ethanol extract downregulated tyrosinase and tyrosinase-related protein 1. In addition, the n-hexane fraction of S. hydrangeoides leaf (HFSH) exhibited significant anti-melanogenic activity among the various solvent fractions tested without reducing the viability of B16F10 cells. Taken together, these results indicate that extracts from S. hydrangeoides leaf can influence cellular processes via modulation of tyrosinase activity. Hence, S. hydrangeoides can be used as a whitening agent in the cosmetic industry and as a therapeutic agent for treating hyperpigmentation disorders in the clinic.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.3B
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• pp.265-276
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• 2011

Precipitation data and groundwater level data were collected for Korean peninsular and Jeju island. The relationship between precipitation and groundwater level and the correlation between the moving average of precipitation and goundwater level were analyzed. Critical infiltration, which is the spatially averaged maximum daily infiltration depth over interested region, is considered when the precipitation data was modified for moving average process and correlation between the moving average of modified precipitation and groundwater level. High correlation regions, which have greater than 0.6 correlation coefficients, were selected after the analysis with ciritical infiltration. Twenty-six regions were selected for high correlation regions. If we divide the regions by administrative district, there are nine regions for Gyungsang-Do, five regions for Chunchung-Do, four regions for Gyunggi-Do and Gangwon-Do, three regions for Jolla-Do, and one region for Jeju island. The groundwater level data for high correlation regions shows obvious response after precipitation event and there are few cases with abrupt change in groundwater level without precipitation-related event.

• Research in Plant Disease
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• v.25 no.2
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• pp.79-83
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• 2019

To investigate the incidence status of lily viruses on Jeju island, lily samples were collected from 2015 to 2018 and examined for virus infection using RT-PCR. Of the viral infections, mixed and single infections were 70.0% and 17.9%, respectively. The incidence of mixed infections was highest for PlAMV and LSV as 43.4% in 2015; PlAMV, LSV 33.1% in 2016; LSV, LMoV 10.2% in 2017; and PlAMV, LSV, LMoV and CMV 15.8% in 2018. The incidence of PlAMV was observed to be 82.0% in 2015, 49.4% in 2016, 13.6% in 2017, and 39.5% in 2018 after the first occurrence of PlAMV in 2013. No symptoms were observed for single infection with LSV. However, in the case of mixed infection with LSV and LMoV, mosaic and leaf malformation symptoms appeared. With mixed infection with LSV and CMV, pale brown necrotic spots appeared, and mosaic and leaf curling were induced. PlAMV was more common in mixed infection than in single infection, and caused necrosis following the development of reddish-brown spots. PlAMV significantly decreased the marketability of lilies owing to the generation of leaf anomalies and curls, and its symptoms were more severe in mixed infections.

• Animal Systematics, Evolution and Diversity
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• v.29 no.1
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• pp.31-35
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• 2013

Two sponges, Stelletta subtilis (Sollas, 1886) and Stryphnus sollasi n. sp., were collected from depth of 24-30 m at Jeju-do Island and Chuja-do Island by SCUBA diving from July 2003 to June 2010. The new species Stryphnus sollasi n. sp is similar with Stryphnus niger Sollas, 1886 in the composition of spicules, however they differ in colour and spicule size. This new species has smaller oxeas and larger oxyasters than those of S. niger. This new species has two size categories of oxyaster but S. niger has one size category of oxyaster. The colour of S. sollasi n. sp is white, but the latter puce black. Stelletta subtilis (Sollas, 1886) is first recorded in Korean fauna.

• Korean Journal of Environmental Biology
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• v.28 no.4
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• pp.223-230
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• 2010

To investigate the variations of physico-chemical factors in four stations (Hanlim, Aewol, Sinchon, Hamdeok) at Jeju coastal area, Water temperature, Salinity, dissolved oxygen (DO), pH, chemical oxygen demand (COD), suspended solid (SS), ammonia-nitrogen ($NH_4-N$), nitrite-nitrogen ($NO_3-N$), nitrate-nitrogen ($NO_2-N$) were analysed. The ranges of water temperature were from 26.23 to $28.6^{\circ}C$, the salinity were from 31.4 to 32.88‰, the pH were from 8.15 to 8.35, the chemical oxygen were from 0.48 to 0.91 mg $L^{-1}$. A total of 52 strains of marine actinomycetes was isolated from Jeju Island coastal area. They were characterized by determining morphological and physio-biochemical properties, the API kit and confirmed by molecular methods including partial sequencing of 16S rRNA. A neighbor-joining tree of partial 16S rRNA sequences divided the 52 isolates in 2 major groups, 22 strains of Gram positive bacteria/Actinobacteria (division)/Actinomycetales (order)/Streptomycineae (suborder)/Streptomycetaceae (family)/Streptomyces (93.1%) and 2 strains of Streptospotangineae (suborder)/Nocardiopsaceae (family)/Nocardiopsis (6.9%).

• Animal Systematics, Evolution and Diversity
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• no.nspc5
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• pp.81-104
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• 2005

Based on our insect collecting trip to the Is. Jin-do, Jeollanam-do Province from June 29 to July 1, 2005, a total of 573 lepidopterous species belonging to 37 families are reported, with adding 122 species new to the locality During our survey, the most dominant species was Cryptolechia malacobyrsa Meyrick (Oecophoridae), followed by Sandrabatis crassiella Ragonot (Pyralidae) and Yponomeuta tokyonellus Matsumura(Yponomeutidae), and the family Noctuidae (165 spp.) was the most diverse taxon in species number. We here also discuss the species representing the climatic feature in the island and compare the species diversity with those of other two major islands in Korea, Is. Geoje-do and Is. Jeju-do. Among the species recognized in this study, two species, Epilepia dentata (Matsumura and Shibata) and Meganola costalis (Staudinger) are recorded in Korea for the first time, in spite of the presence of previous notes on the species which is invalid. The adults and genitalia of the two species are illustrated and described briefly.

• The Korean Journal of Mycology
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• v.40 no.1
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• pp.39-43
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• 2012

The knowledge of native wild mushrooms traditionally using in Jeju Island, that have specific native environment and various biodiversity, was investigated. From Jeju and Seogwipo cities including 7 provinces 4 locals, so total 50 villages, data was collected in the entire area and voice of the 93 elderly people between the age of fifty and ninety were recorded. As a result, total 23 native wild mushrooms were used in which 2 species were poisonous mushrooms, 7 species were medicinal mushrooms, 2 species was used for folk religion, 2 species were not used for living but for attention and 12 species were edible mushrooms. Also, a total of 267 cases of traditional knowledge was collected, in which 197 cases were about edible mushrooms for 12 species, 43 cases were about poisonous mushrooms for 2 species, 16 cases were about medicinal mushrooms for 7 species. Interestingly, the fortune for agriculture was told depending on spore mass release of Cyathus stercoreus which grows in animal feces and compost. It is considered as the distinctive traditional knowledge of Jeju Island.

• Journal of the Korean Geographical Society
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• v.43 no.2
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• pp.171-187
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• 2008

Islands are vulnerable to outer influences due to their small size and isolation. Tourism often becomes an important development focus because of their unique culture and nature. Jeju-do, as well as other islands, has experienced such development mostly led by central government, and the regional change was understood as the outcome of global influences without much concern with the local response or strategy. Thus, vulnerability has been the key theme in island development studies. This paper examines the current state of island development as an outcome of locals' alternating strategy in which the islanders accept the central government's plan, but express their demands to modify them. It is reflected in the electoral preference for ruling or oppositional parties, local movements against central government's development plans, and the spatial organization of tourism sites from a few growth centers to more dispersed, balanced development. These suggest that the current state of island development is not derived from unidirectional global forces, even if islands are peripheral. Rather, it is the outcome of an alternating strategy of Jeju locals accepting the central government development plans while managing them for local benefits.

• Journal of Soil and Groundwater Environment
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• v.12 no.4
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• pp.60-71
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• 2007

Groundwater from public wells was monitored during one year with two month interval for hydrogeochemical parameters and chlorofluorocarbons (CFCs) as environmental tracers in Jeju Island. Concentrations of major cations and $SiO_2$ show variation less than 10% whereas $NO_3$ and dissolved oxygen (DO) showed larger variation though DO variation did not change oxic or suboxic condition. $NO_3$ concentration has no consistent seasonal pattern with the largest variation of 35%. Groundwater ages determined by CFCs became temporarily younger by 5 years in October for groundwater with ages of 15 to 25 years, which can be attributed to infiltrating water in rainy season. Compared to air temperature, groundwater temperature has much smaller variation with no phase difference, which can be accounted for by a two-component model consisting of infiltrating water from surface and deeper groundwater with negligible temperature variation. The relatively small variation in groundwater age and temperature indicates that groundwater recharge through fast flow-paths is much smaller compared with basal groundwater in terms of aquifer storage.

• Korean Journal of Environment and Ecology
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• v.22 no.6
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• pp.648-657
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• 2008

This research was conducted to investigate the breeding density and seasonal food items of the magpies in Jeju Island and the near-manned islets. The examination of nest distribution to determine breeding density was performed during breeding season from February 2006 to April 2008, and that of food items from May 2006 to February 2008. A total of 2,113 nests were found across Jeju Island, the average density was $1.33\;nest/km^2$, and the magpies were distributed up to 600 meters above the sea level. The nest density was the highest in the central areas of Jeju Island, with 688 nests at $3.61\;nest/km^2$, while that in the eastern areas was the lowest, with 214 nests at $0.66\;nest/km^2$. In terms of the number of nests depending on the height above the sea level, 1,172 nests, which was equivalent to the density of $1.85\;nest/km^2$, was observed below 100m and highest among the intervals of height, but 16 nests found at 500-600m were the lowest, corresponding to $0.20\;nest/km^2$. The number of nests found in the manned islets near Jeju Island was eight in Biyang-do with the density of $15.38\;nest/km^2$, nine in U-do with $1.49\;nest/km^2$, and one in Gapa-do with $1.15\;nest/km^2$, whereas none of nests were observed in Mara-do. The contents of stomach consisted of 17 types of prey sources including countless bones, eggshells, plants, and seed, most of which were the individuals of the order Coleoptera. In spring and summer, the foraging frequency for invertebrate animals such as insects was high, but less than 30% in winter. In contrast, the magpies preyed upon plants and seeds at the frequency of 10% and 30%, respectively, in spring, while the foraging frequencies for both of them were 100% in winter and higher than any of other seasons. Eggshells and bones of birds were also detected infrequently. If the density of the magpies, which may play role as the upper predator within the ecosystem, increases, it would be expected to affect directly the reduction of the number of the species and population of endemic animals such as small birds and reptiles, etc. Therefore, it is considered that long-term monitoring for the density of the magpies and precaution is prerequisite to minimize adverse effects on ecosystem.