• Asian Pacific Journal of Cancer Prevention
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• v.15 no.17
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• pp.7091-7095
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• 2014

Background: The study aimed to evaluate the incidence of CpG island promoter methylation of BMP6, a member of the transforming growth factor beta family, in tissue samples from colorectal cancers (CRC) and look for its association with BMP6 expression and clinicopathological correlation. Materials and Methods: Methylation specific PCR for the BMP6 promoter region was performed with 85 frozen tissue samples of CRC and 45 of normal colon. Methylation status of MLH1 was also determined by the same method. Expression of BMP6 was evaluated by immunohistochemistry (IHC), using Allred's scoring system. The methylation status was analyzed against clinical and pathological parameters in CRC. Results: The study revealed BMP6 hypermethylation in 34 of 85 tumor specimens (40%), and 15 out of 45 normal tissue samples from CRC (33%). The incidence of hypermethylation was inversely correlated with IHC score. Allred's scores of 7 or more were correlated with lower frequency of BMP6 hypermethylation (29% compared to 50% in the remaining, p-value 0.049). However, there was no association between hypermethylation status and any clinicopathological parameters. The methylation status of BMP6 was not correlated with that of MLH1, a key methylation determinant in CRC. On survival analysis, there was no significant difference in progress-free survival (PFS) between the cases with and without hypermethylation (2-year PFS 74% and 76%, respectively). Conclusions: CpG island methylation of BMP6 is found in high frequency in CRC and this epigenetic event is associated with suppressed protein expression in the tumor tissue. However, the marker is not associated with tumor progression of the disease.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.10
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• pp.5069-5074
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• 2012

Objectives: The purpose of this study was to determine the relationship between methylation status of the Dact1 gene and MTHFR a1298c polymorphic forms in transitional cell carcinoma tissues in a Chinese population. Methods: Polymorphisms of folate metabolism enzyme gene MTHFR were assessed by restrictive fragment length polymorphism (RFLP) methods and PCR-based DNA methylation analysis was used to determine the CpG island methylation status of the Dact1 gene. Associations between the methylation status of the Dact1 gene and clinical characteristics, as well as MTHFR a1298c polymorphisms, were analyzed. Results: aberrant methylation of the Dact1 gene was found in 68.3% of cancer tissues and 12.4% of normal tissues,. The methylation rate of the Dact1 gene in cancer tissues was significantly higher in patients with lymph node metastasis than in those without lymph node metastasis (46.3% vs. 17.2%, P = 0.018). No association was found between aberrant DNA methylation and selected factors including sex, age, tobacco smoking, alcohol consumption and green tea consumption. After adjusting for potential confounding variables, variant allele of MTHFR a1298c was found to be associated with methylation of the Dact1 gene. Compared with wild type CC, the odds ratio was 4.33 (95% CI: 1.06-10.59) for AC and 4.95 (95% CI: 1.18-12.74) for AA. The N stage in TNM staging and the occurrence of lymph node metastasis were associated with an MTHFR 1298 AA+AC genotype (P<0.05). Conclusion: MTHFR 1298 AC and AA genotypes might help maintain a normal methylation status of the Dact1 gene, aberrant CpG island methylation of which is closely related to the genesis and progression of transitional cell carcinoma.

• Journal of Korean Society for Atmospheric Environment
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• v.23 no.5
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• pp.612-624
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• 2007

The real-time monitoring of radon ($^{222}Rn$) concentrations has been carried out to evaluate its ambient background concentration levels in Gosan site, Jeju Island between January 2001 and December 2004. In addition, the atmospheric TSP aerosols have been sampled, and their ionic and metallic components were analyzed to understand the characteristics of air pollution. The mean concentration of radon was $3,121{\pm}1,627\;mBq/m^3$, and the seasonal mean concentrations for spring, summer, fall and winter seasons were 2,898, 2,398, 3,571 and $3,646\;mBq/m^3$, respectively, The hourly concentrations have shown the highest value at 7 a.m. and the lowest value at 2 p.m. From the backward trajectory analyses, the radon concentrations have increased, when the air parcels were moved from the Chinese continent to Jeju area. On the other hand, they have decreased, when the air parcels from the North Pacific Ocean. In the analytical results of ionic species and metal elements of TSP aerosols, the concentrations of $nss-{SO_4}^{2-}$ and S were higher in June and March. Meanwhile, the concentrations of other anthropogenic species as well as soil components were mostly higher in March and April. On the basis of factor analysis, the TSP aerosols at Gosan area were largely influenced by soil sources, followed by anthropogenic sources and marine sources. From the result of backward trajectory analyses, the concentrations of $nss-{SO_4}^{2-},\;{NO_3}^-$, Al and Ca were mostly higher, when the air parcels moved from Chinese continent to Jeju area. On the other hand, their concentrations were lower, when the air parcels drifted from the North Pacific Ocean.

• The Korean Journal of Malacology
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• v.25 no.3
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• pp.197-201
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• 2009

This study was conducted to investigate the genetic characteristics of wild population of Pacific abalone, Haliotis discus hannai in Dokdo island. We used six polymorphic microsatellite marker to investigate the genetic diversity and population structure. The loci Hdh1321 and Hdh512 had the highest number of allele (34 and 22 respectively) and loci Hdh145 and Awb083 had the lowest (5 and 7 respectively). The mean number of allele per locus was 14.8. The average observed and expected heterozygosities were 0.664 and 0.824 respectively, and the average $F_{IS}$ was 0.195. We compared the population genetic parameters of Dokdo population with previously published data of the same species. At the result, the parewise $F_{ST}$ test showed significant difference between the Dokdo population and six populations (published data), suggesting that the genetic relationship of Dokdo population was separated from six populations.

• Fisheries and Aquatic Sciences
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• v.10 no.2
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• pp.74-85
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• 2007

Pacific anchovy (Engraulis japonicus) eggs were collected during the spawning season (2000-2003) using a revised ring net in the coastal waters adjacent to the Geum River Estuary in the West Sea of Korea (Yellow Sea). Anchovy eggs were present from May to September, showing a peak in spawning from June to July when the water temperature and salinity were $17-27^{\circ}C$ and above 30.00 psu, respectively. During the main spawning season, no clear diel cycle (regarding the 24-h sampling period of dusk, night, dawn, and daytime) was detected in the vertical distribution of anchovy eggs near Eocheong Island (50-60m depth). Judging from the developmental stages of the collected eggs, it appeared that anchovies spawned mostly at night and that the eggs hatched at dusk and during the night. The density of anchovy eggs was high in the southwest-northeast direction in June, and spawners appeared to move offshore in July. Mean egg density was higher in June 2002 than in June 2003 when water temperatures and salinities were lower. This study on the spatiotemporal distribution of eggs will contribute to developing management plans for the Pacific anchovy in Korea.

• Korean Journal of Ichthyology
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• v.27 no.2
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• pp.153-158
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• 2015

Five specimens of Lethotremus awae (Cyclopteridae) were collected from the northern coastal waters of Jeju Island, Korea, during a survey on larval and juvenile fishes flocking to aquatic lamp in 2004 ~ 2007. They were characterized by having a spherical body with three barbel-like tubes on head and the first dorsal fin overgrown by skin with undiscernible rays as well as VIII-9 dorsal fin rays, 8 ~ 9 anal fin rays and 22 ~ 23 pectoral fin rays. A new Korean name, "Eom-ji-do-chi", was proposed for the species.

• Journal of Ecology and Environment
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• v.36 no.4
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• pp.217-222
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• 2013

Sea temperature in the South Sea of Korea has been increased over the last decades. Seabirds are sensitive to changes in food availability in marine environment. In this study, we investigate the diet of Black-tailed gulls (Larus crassirostris) during the breeding season to identify changes of marine environment and biological response such as breeding performance in the South Sea of Korea. A total of 22 fish species or family (n = 128) from regurgitates by chicks were collected on Hongdo Island in 2002 and 2012. The most important prey item was Japanese anchovies (Engraulis japonicas). Proportion of Anchovy in diet increased in 2012 (70.5%) compared to 10 years ago (27.5%). Some species were newly found in 2012: Spotted chub mackerel (Scomber australasicus), Pacific sand lace (Ammodytes personatus), White ventral goby (Acanthogobius lactipes), Silver-strip round herring, Multicolorfin rainbowfish (Halichoeres poecilopterus), Silverside (Hypoatherina tsurugae), Surfperch (Neoditrema ransonneti) and Spotnape ponyfish (Leiognathus muchalis), but not in 2002. Especially, sub-tropic fish such as Kammal thryssa (Thryssa kammalensis), and Rosefish (Helicolenus hilgendorfi) were frequently observed in the diet of 2012. These results might reflect the increase of sea temperature in the South Sea of Korea.

• Journal of Korean Society for Atmospheric Environment
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• v.13 no.3
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• pp.179-191
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• 1997

The concentrations of organic and elemental carbon were determined using fine particle samples collected from Kosan, Cheju Island during the summer seasons of 1994 and 1995. The daily mean concentrations of organic and elemental carbon for each measurement period were 3.74 and 0.27 $\mu\textrm{g}$/㎥ in 1994, while those of 1995 were 2.36 and 0.10 $\mu\textrm{g}$/㎥, respectively The concentrations of organic carbon were higher than those commonly observed from clean areas around the world, but those of elemental carbon were lower than, or comparable to, other clean areas in the world. The resulting ratios of total carbon to elemental carbon at this site were thus higher than those seen from other metropolitan and non-polluted regions abroad. In addition according to our analysis, the 1994 measurement period can be classified into two periods: enhanced (July 20 and August 1) and reduced levels (August 2 and 9) of the carbonaceous species. The observed difference between two periods may be in part accounted for by the air trajectories representing each period. During the former period, the air masses from the Asian continent and Japan were dominant, while the air masses from the North Pacific Ocean came during the latter period. OC/EC ratios at the site were calculated to predict the possible formation of secondary organic aerosol . Based on our observations, we suggest that the formation of secondary organic aerosol might be an important pathway to the production of organic carbons.

• ALGAE
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• v.30 no.1
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• pp.15-33
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• 2015

When the generitype Centroceras clavulatum, a presumed cosmopolitan warm temperate to tropical red alga, was discovered to have a biogeographic distribution limited to the Pacific Ocean using molecular and morphological evidence, the taxonomy in the genus Centroceras was thrown into chaos worldwide. An analysis of what species was, or were, previously identified as C. clavulatum in Bermuda is the focus of the present molecular (COI-5P, rbcL) and morphological study. Two novel species are proposed, C. arcii sp. nov. and C. illaqueans sp. nov., and the distributions of three taxa recently segregated in the 'C. clavulatum complex' of the western Atlantic, C. gasparrinii, C. hyalacanthum, and C. micracanthum, have been expanded to include Bermuda. C. arcii is shown to be morphologically cryptic with C. micracanthum, and remains best distinguished by its COI-5P barcode sequence.

• Journal of Korea Port Economic Association
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• v.17 no.1
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• pp.129-157
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• 2001

In Korea, the quantity of waste is excessive as a result of increases in population and consumption following industrialization. This has resulted in urban environmental problems, a shortage of landfills and pollution around landfills. Thus, there is a need to conduct research in order to find an effective long-term alternative. In Japan, there are more landfills at sea than there are on land. Based on projections for Korea, on-land landfills in the metropolitan area will be filled to capacity by 2020 and then be closed. This research recommends the construction of landfill sites at sea as an alternative waste disposal method. Its findings show that the most the suitable sites for landfills within the Seoul metropolitan area are the regions around Jangbongdo Island and Mueido Island. It also suggests that the best way to transport waste is through the Kyungin Canal from the middle collection center to the lower Han River. The estimated cost of constructing an at-sea landfill to be used for 50 years is approximately two trillion won, with a total construction time of 10 years. In the future, further research related to this study will be conducted in order to ensure that environmentally-friendly landfills are built.