• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.3
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• pp.364-372
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• 1995

On the outbreak of paralytic shellfish poisoning in April 1993 in most of shellfish harvesting areas in Jinhae Bay, Korea, to clarify the toxin production of causative organism Alexandrium species, 19 axenic clonal isolates established from the benthic resting cysts in three different stations of those culture grounds were subjected to PSP toxin analysis by HPLC. Individual toxin content per cell was highly variable among the strains isolated from a sampling area and originated from an individual cyst. Average toxin contents in those areas revealed higher values of 54-70 fmol/cell. Toxin profiles included C1/C2(epiGTX8/GTX8), GTX1/GTX4 and neoSTX as the major components, and GTX2/GTX3, GTX5, C4, dcSTX and STX as the minor or sporadic ones. neoSTX on the dominant toxins showed not only most diverse compositional changes comprising $5-54 mol\%$ ranges but also no detection on the half of the strains examined, which were implicated in arising of heterogeneity with a genetic trait within a geographical region. When average toxin composition was compared, carbamate toxins comprised large proportions of $57\%,\;54\%\;and\;67\%$ as total toxin in St. 1, St. 2 and St. 4, respectively. These results suggested that an extensive paralytic shellfish toxification in Jinhae Bay could be largely due to the production of highly potent carbamate toxins in the causative dinoflagellate Alexandrium species.

• Fisheries and Aquatic Sciences
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• v.8 no.2
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• pp.76-82
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• 2005

We analyzed the paralytic shellfish poisoning (PSP) toxins of the toxic marine dinoflagellate Alexandrium tamarense collected from Dadaepo and Gaduck-do in Busan and from Sujeong-ri in Jinhae Bay, Korea, in April 2003. We also analyzed the PSP toxin of mussels (Mytilus galloprovincialis) and oysters (Crassostrea gigas) collected around Busan and Jinhae Bay. PSP toxin analyses were conducted by high performance liquid chromatography (HPLC). Fifteen cultured A. tamarense isolates contained 2.78 to 57.47 fmol/cell, with nearly identical toxin profiles: major components C2, GTX4; minor components C1, GTX1, NEO; and trace components GTX2, GTX3, STX. PSP toxin contents were 0 to $492\;\mu{g}$ STXeq/100 g in mussels and 0 to $48\;\mu{g}$ STXeq/100 g in oysters. Mussels at Gijang and Sujeong-ri contained the most PSP toxin contents ($492\;\mu{g}\;STXeq/100\;g\;and\;252\;\mu{g}\;STXeq/100\;g,\;respectively$), exceeding the quarantine level ($80\;\mu{g}$ STXeq/100 g). Their dominant toxin components were C2, C1, GTX2, and GTX3; the minor components GTX1, GTX4, GTX5, and NEO were sporadically detected. Phytoplankton contained 0.774 fmol/L seawater and 1.228 fmol/L seawater at Gijang and Sujeong-ri in April. At that time, Alexandrium cells were present in the water column at Gijang at 2,577 cells/mL and at Sujeong-ri at 6,750 cells/mL. Overall, we found the high and similar PSP toxin contents in AZexandrium isolates and mussels, and a correlation between occurrence of toxic Alexandrium cells in the water column and mussel intoxification. High densities of toxic Alexandrium cells in the water column immediately preceded shellfish intoxification at Gijang and Sujeong-ri in April.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.4
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• pp.366-372
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• 2009

This study looked at toxicity of Mediterranean mussels, Mytilus galloprovincialis, which had accumulated paralytic shellfish toxins (PST) from early March to late May 2005 at Jinhae Bay, Korea. Alexandrium sp. was observed in low densities (< 1,000 cells/L) at the beginning of the study in March, increased rapidly in April, declined rapidly and disappeared in May. Although low densities of Alexandrium sp. were observed in March, mussel toxicity exceeded regulation level ($80{\mu}g$ STXeq. /100 g). Peak PSP (Paralytic Shellfish Poisoning) toxicity in the mussels occurred during high Alexandrium sp. cell densities in April. Mussels toxicity decreased with decline of Alexandrium sp. cell density. Major toxin components identified were $GTX_1$, $GTX_4$, followed by $C_1$, $C_2$, $GTX_2$, $GTX_3$ and neoSTX. Trace or sporadic toxin components were STX, $GTX_5$, $dcGTX_2$, $dcGTX_3$ and dcSTX. Toxin component analysis from the middle to end of the study showed that $11{\beta}$-epimers ($GTX_{3,4}$, $C_2$) were converted into $11{\alpha}$-epimers ($GTX_{1,2}$, $C_1$) and started to determine STX.

• Journal of the Korean Society for Railway
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• v.18 no.6
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• pp.513-521
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• 2015

When a GTX travels through a deep-level underground tunnel at a speed of 180km/h, ear-discomfort in passengers due to the pressure wave generated could be an issue due to the small cross-sectional area. Therefore, appropriate pressure-tightness values for GTX trains must be secured as a countermeasure. In this paper, a 1D numerical analysis was conducted to determine the pressure-tightness coefficient which allows a pressure change meet the criteria. The pressure transients in a tunnel and in a passenger car are predicted considering an A-line underground tunnel with a length of 37km and its operation schedule. The required pressure-tightness of the car is predicted to be three seconds and 6 seconds respectively for a single track and a double- track tunnel to prevent aural discomfort in passengers. The result of this study are expected to serve as useful information to those involved in the development of various solutions to improve air-tightness of GTX passenger cars.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.1
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• pp.25-38
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• 2023

Seoul Metropolitan Urban Railroad has an undecided route that does not estimate the passenger transportation route. For this reason, the fare of the urban railroad is calculated by the assumption that passengers pass through the minimum distance. Therefore, if a transfer station on the urban railroad is added, the trip shortest distance could be decreased and the fare also reduced. In this study, this phenomenon defines the fare paradox(Shin, 2022) and estimates the impact of the fare paradox by opening the GTX-A. For this purpose, a scenario before and after the opening of the GTX-A has been established, and an additional fare has been estimated by proportional planning of the Seoul Metropolitan Integrated Distance Based Fare Policy. Fare Paradox was analyzed to about 0.024 % of daily income. It is expected to be used as a plan to determine a rate policy, such as the establishment of a GTX-A, B, C, D, and a light rail line.

• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.128-128
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• 2003

The annually outbreak of paralytic shellfish poisoning (PSP) were caused by toxic dinolagellate A. tamarense and A. catenella in Korea. The purpose of this study were to investigate the distribution of PSP-causative organisms, A. tamarense and A. catenella and their species classification. Sediment (Saemangeum, the south open sea) and water samples (southeastern coast) were sampled to establish clonal isolates in 2003. After isolation and purification, strains were cultured under $17^{\circ}C$, f/2 media, 14:10=L:D cycle. PST analysis and species identification were performed by HPLC-FD method and specific DNA probe, respectively. Thirty-ons strains were isolated from the Saemangeum reclamation, southeastern coast including Jinhae Bay and south open sea. PSTs were detected in all cultured strains. In eight strains from south offshore, major toxin components are GTX5, C1/2 and minors are GTX3/4, dcGTX3, neoSTX. Sixteen strains from south coastal area have GTX1/4, neoSTX, C1/2 as major toxin components and GTX2/3 as minors. Seven strains from the Saemangeum reclamation have GTX5, C1/2 as major toxin components and GTX1/2/3/4 as minors. Thus, among eight south offshore isolates, four A. tamarense have more toxic (38.31~l19.16 fmol.$cell^{-1}$) than A. catenella (3.78~13.13 fmol.$cell^{-1}$). With the previous results of different toxin composition, toxin components and toxin contents, .it is toxin profile that could used to diagnosis of regional toxic population and geographical distribution of both A. tamarense and A. catenella and their toxigenic strains.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.6
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• pp.924-928
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• 2005

Toxin profiles of the paralytic shellfish poison (PSP) detected from domestic shellfishes collected at the market and imported. shellfishes were invested by fluorometric HPLC. Total 9 components in PSP were analysed from the imported ark shell, such as saxitoxin (STX), decarbamoylsaxitoxin (dcSTX), gonyautoxin (GTX) - 1,2,3,4,5, Cl and C2. Among those toxins, 7 components except for GTX1,4 were detected from domestic shellfishes and showed different toxin contents and toxin compositions by species. Only C group toxin (Cl +2) contained in short necked clam and hard clam $(0.06\~0.56\;nmole/g)$ which living under soil but, in the blue mussels and oysters which cultured in the open sea water, showed more higher toxicity and complicate toxin compositions. Toxin compositions in bloody clam and purplish washington clam were very different in some samples even in same species. GTX4 and GTX5 were higher in imported scallop and STX was higher in imported ark shell than other species.

• Korean Journal of Food Science and Technology
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• v.40 no.1
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• pp.8-14
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• 2008

This study was performed to establish analysis methods, and evaluated for grayanotoxin in domestic/foreign honey and wild honey. The molecular weight of grayanotoxins I, II and III, excluding grayanotoxin III that has been commercialized, were analyzed by LC-MS/MS. Then, the molecular structure of grayanotoxins I and II were analyzed by NMR. A total 111 samples (25 Korean honey, 21 Korean wild honey, 13 Korean honeycomb honey, 44 foreign honey, 8 foreign wild honey) were examined to determined whether or not each sample contained grayanotoxins I, II, and III. The honey samples were mixed with methanol and loaded into a tC18 cartridge, the filtrate was diluted with water, and the mixture was then analyzed by ESI triple-quadrupole LC-MS/MS. Grayanotoxins were only found in the foreign wild honey and were not detected in Korean honey, Korean honeycomb honey, or Korean wild honey. Three of the samples contained grayanotoxin I, II, and III, and one sample contained only grayanotoxins I and III. The lowest level for grayanotoxin I was 3.13 ${\pm}$ 0.00 mg/kg, and the highest level was 12.93 ${\pm}$ 0.01 mg/kg. The levels of grayanotoxin II were 0.84 ${\pm}$ 0.01 mg/kg, 0.92 ${\pm}$ 0.00 mg/kg and 1.08 ${\pm}$ 0.01 mg/kg, respectively. The lowest level of grayanotoxin III was 0.25 ${\pm}$ 0.01 mg/kg and the highest level was 3.29 ${\pm}$ 0.74 mg/kg. Through this study, safety management for foreign wild honey has been enabled.

• Biomedical Science Letters
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• v.23 no.3
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• pp.238-250
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• 2017

Patient's primary tumor-derived tumor cell lines likely represent ideal tools for human tumor biology in vitro and in vivo. Here, we describe eight human gastric carcinoma cell lines derived from established tumors in vivo upon subcutaneous transplantation of primary gastric carcinoma specimens in BALB/c nude mice. These xenografted gastric tumor cell lines (GTX) displayed close similarity with primary gastric tumor tissues in their in vivo growth pattern and genomic alterations. GTX-085 cells were resistant to cisplatin, while GTX-087 was the most sensitive cell line. GTX-085 was the only cell line showing a metastatic potential. Epithelial cell adhesion molecule (EPCAM) expression was especially strong in all tissue samples, as well as in cell cultures. GTX-139, the largest tumor graft obtained after injection, displayed distinct expression of CD44v6, fibroblast growth factor receptor 2 (FGFR2), and prominin 1 (PROM1, also known as CD133). In summary, we established eight xenograft gastric cancer cell lines from gastric cancer patient tissues, with their histological and molecular features consistent with those of the primary tumors. The established GTX cell lines will enable future studies of their responses to various treatments for gastric cancer.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.745-755
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• 2010

GTX(Great Train Express), the wide area express train of a big city center of metropolitan area, is the best new transportation method able to realize 'Low Carbon Green Growth' for solving traffic congestion of the metropolitan area with the connection the metropolitan area into 40-minute life zone by speeding up the standardized velocity, making the route straight and reducing the compensation of land using the space of 40~50m below the ground. In the transportation sector all over the world, if it turned into the public transportation system focusing on the train at a point of time that low carbon green revolution takes the initiative, national competitiveness would be enhanced by reducing the emission of carbon from cars by 1/6. Accordingly, this study is to look into the efficient operation in accordance with GTX construction superintended by currently Gyeonggi province and to consider the optimum operation plan of GTX that are proper for the actual circumstances of the country by comparatively analyzing overseas cases that took their positions as new transportation by curtailment of transit time through highspeed such as London area, Paris area, and Tokyo area etc that are similar to Korean metropolitan area.