• 한국생태학회:학술대회논문집
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• 1999.05a
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• pp.137.1-137.1
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• 1999

• Proceedings of the Korea Water Resources Association Conference
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• 2005.09a
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• pp.452-453
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• 2005

• Journal of Microbiology and Biotechnology
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• v.6 no.5
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• pp.340-346
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• 1996

In order to find out if staphylococci occur in significant numbers in Korean fermented fish products, a total of 40 different fermented fish products were collected from different markets in Korea and analyzed for their physico-chemical and microbiological states. The pH, salt concentration and water activity of the products were measured and the total viable cell count and the number of Staphylococcus grown on mannitol salt agar were determined. The identification of the strains of Staphylococcus were made by API Staph Strip and MIS identification kits, and the physiological properties of the identified strains were further characterized by different conventional methods. The pH, salt content and water activity of fermented fish samples varied widely from 4.8 to 7.1, 7.4-28.7$%$ and 0.77-0.84, repectively, depending on the type of product. The total viable cell count varied from $10^4-10^9$ cfu/ml, and most of the samples had $10^5-10^6$ cfu/ml No correlation was found between the viable cell count and the pH, NaCl concentration and water activity of the samples. Among the 35 colonies identified as Staphylococcus strains by the identification kits, S. xylosus was the most frequently occurring strain marking 17, and S. warneri was 8, S. epidermidis 4 and S. cohnii 2. S. hominis, S. saprophyticus, S. haemolyticus and S. aureus were also identified once each. In some samples (K-3, P-6, K-8, G-5 and G-10), 2-3 different species of Staphylococcus were found. Considering the region of sampling, among the 10 samples from Kunsan 5 were identified as S. warneri, while in the other regions S. xylosus was predominant. Although the physiological characteristics of the identified strains were generally consistent with those in Bergey's Manual, some discrepances were also observed. All the strains were highly salt tolerant, growing in the media containing over 18$%$ NaCl. All the strains except S. aureus (G-11) showed negative in hemolysis activity, plasma coagulation and DNase tests. All the strains including S. aureus (G-11) showed negative in enterotoxin test.

• Parasites, Hosts and Diseases
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• v.47 no.3
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• pp.307-310
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• 2009

Fishborne trematode (FBT) metacercariae were investigated in yellowfin goby, Acanthogobius flavimanus, collected from Shinan-gun and Muan-gun, Jeollanam-do (province), Korea. All collected fishes were examined using the artificial digestion method. In all of 15 gobies from Aphae-myeon in Shinan-gun, metacercariae of Stictodora spp. (334 metacercariae/fish), Heterophyes nocens (153/fish), and Heterophyopsis continua (20/fish) were detected. In 2 of 14 gobies from Jido-myeon in Shinan-gun, 8 Echinostoma hortense metacercariae in total were detected. In 15 gobies from Haeje-myeon in Muan-gun, the metacercariae of H. continua were found in 100%, Stictodora spp. in 86.7%, and H. nocens in 6.7% of fish examined. The average numbers of metacercariae per infected fish were 23.3 (H. continua), 416.0 (Stictodora spp.), and 2.0(H. nocens), respectively. The metacercariae of E. hortense found in gobies were elliptical, with 150 ${\times}$ 138 ${\mu}m$, in average size, and had 27 collar spines on the head crown. The above results suggest that yellowfin gobies from 2 localities may be the potential infection sources of FBT. Moreover, it is proved for the first time that the yellowfin goby, A. flavimanus, acts as a second intermediate host for E. hortense.

• Parasites, Hosts and Diseases
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• v.54 no.3
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• pp.363-368
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• 2016

We describe here the mass death of predatory carp, Chanodichthys erythropterus, in Korea induced by plerocercoid larvae of Ligula intestinalis as a result of host manipulation. The carcasses of fish with ligulid larvae were first found in the river-edge areas of Chilgok-bo in Nakdong-gang (River), Korea at early February 2016. This ecological phenomena also occurred in the adjacent areas of 3 dams of Nakdong-gang, i.e., Gangjeong-bo, Dalseong-bo, and Hapcheon-Changnyeong-bo. Total 1,173 fish carcasses were collected from the 4 regions. To examine the cause of death, we captured 10 wondering carp in the river-edge areas of Hapcheon-Changnyeong-bo with a landing net. They were 24.0-28.5 cm in length and 147-257 g in weight, and had 2-11 plerocercoid larvae in the abdominal cavity. Their digestive organs were slender and empty, and reproductive organs were not observed at all. The plerocercoid larvae occupied almost all spaces of the abdominal cavity under the air bladders. The proportion of larvae per fish was 14.6-32.1% of body weight. The larvae were ivory-white, 21.5-63.0 cm long, and 6.0-13.8 g in weight. We suggest that the preference for the river-edge in infected fish during winter is a modified behavioral response by host manipulation of the tapeworm larvae. The life cycle of this tapeworm seems to be successfully continued as the infected fish can be easily eaten by avian definitive hosts.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.47 no.3
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• pp.56-62
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• 2010

Weakly electric fish uses active sensing to detect the distortion of self-generated electric field in the underwater environments. The active electrolocation makes it possible to identify target objects from the surroundings without vision in the dark sea. Weakly electric fish have many electroreceptors over the whole body surface of electric fish, and sensor readings from a collection of electroreceptors are represented as an electric image. Many researchers have worked on finding features in the electric image to know how the weakly electric fish identify the target object. In this paper, we suggest a new mechanism of how the electrolocation can recognize a given target object among object plants. This approach is based on the differential components of the electric image, and has a potential to be applied to the underwater robotic system for object localization.

• Journal of Nutrition and Health
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• v.16 no.1
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• pp.10-20
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• 1983

In order to establish tissue lipid status in animal on feeding of various dietary fat and oils, each group of rats was fed a semisynthetic diet containing 10%(w/w) mackerel oil (MO), eel oil (EO), soybean oil (SO), rapeseed oil (RO) or beef tallow (BT) for 1, 2 and 4 weeks, After each feeding period, levels of cholesterol, triglyceride and phospholipid were measured in serum. Fatty acid ${\leftarrow}$ composition was also investigated in serum and tissue lipids. Levels of total serum cholesterol were lower but HDL-cholesterol were higher in fish oil groups, which resulted in significantly higher ratio of HDL to total cholesterol in the fish oil groups. Fish oil groups, in general, also had lower levels of serum triglyceride and phospholipid than other groups, but S0 group maintained as low phospholipid levrl as fish oil groups. Fatty acid composition of dietary fat was reflected in all the tissues investigated but with varying degrees. Very long chain fatty acids, specific components exclusively found in fish oils were most well reflected in liver and relatively well in serum, whereas linoleic acid and erucic acid of SO and RO in the diet were better shown up in heart and adipose tissue. It attracted a particular attention that major proportions of long chain monoenoic acids $(C_{22:1})$ occurring both in MO and RO were detected separately in liver and heart plus adipose tissue, the result of which strongly indicates that there is a significant difference in metabolism between isomers $(C_{22:1}\;w\;11\;and\;C_{22:1}\;w\;9,\;respectively)$. It is suggested from this study that differences in lipid status as well as in the levels of serum lipids result from uniqueness in metabolism of each different fatty acid and give rise to distinguishable change in serum lipoprotein pattern, followed by diet with different fat sources.

• Parasites, Hosts and Diseases
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• v.50 no.3
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• pp.215-220
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• 2012

The source of human infection with intestinal flukes was surveyed in estuarine fishes, including the dotted gizzard shad, common sea bass, common blackish goby, redlip mullet, black sea bream, and oyster collected from Muan-gun, Jeollanam-do, Korea during August and September 2007. Collected fishes and oysters were artificially digested in pepsin-HCl solution and examined under a stereomicroscope. In 36 shads (Konosirus punctatus) and 20 basses (Lateolabrax japonicus) examined, Heterophyopsis continua metacercariae were found in 58.3% and 100%, and their average numbers were 12.0 and 6.3 per infected fish, respectively. In 34 gobies (Acanthogobius flavimanus) examined, metacercariae of H. continua were detected in 79.4%, Stictodora lari in 97.1%, and Acanthotrema felis in 92.1%, and their average numbers were 45.8, 189.3, and 235.3 per infected fish, respectively. In 37 redlip mullets (Chelon haematocheilus), Heterophyes nocens metacercariae were found in 56.8%, Pygidiopsis summa in 94.6%, and Stictodora fuscata in 45.9%, and the average metacercarial densities were 17.4, 31.3, and 35.1 per infected fish, respectively. In 30 black sea breams (Acanthopagrus schlegeli) and 45 oysters (Crassostrea gigas) examined, no metacercariae were detected. From the above results, it has been confirmed that the dotted gizzard shad, common sea bass, common blackish goby, and redlip mullet from Muan-gun, Jeollanam-do, Korea are infected with the metacercariae of heterophyid flukes.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.52 no.3
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• pp.220-231
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• 2016

Yield-per-recruit (YPR) analysis is used to provide management guidance for the efficient use of a fish cohort. However, the individual fish price per unit weight of small yellow croaker (Larimichthys polyactis) or hairtail (Trichiurus lepturus) increases dramatically by size in Korea. Therefore, age-based production value-per-recruit (PPR) analysis has recently been developed (Zhang et al., 2014). Since age determination requires a substantial amount of money and time and it is even impossible for some fish species, it is difficult to obtain age information to apply the age-based PPR model. Thus, we attempted to develop an alternative method, which uses length data rather than age information, called the length-based PPR analysis. The results revealed that length-based PPR analysis was much more conservative for stock management than the YPR analysis. Furthermore, the PPR analysis was more economically beneficial than the YPR analysis, which can prevent the fish stock from the economic overfishing. In conclusion, the length-based PPR analysis could be a proper approach for stock assessment in the case that the individual fish price per unit weight increases dramatically by size, and this analysis is useful to obtain vital management parameters under data-deficient situation when traditional stock assessment methods are not applicable.

• Korean Journal of Community Nutrition
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• v.18 no.5
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• pp.515-524
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• 2013

Atopic dermatitis (AD) is believed to be associated with the intake of antioxidant nutrients and fatty acids due to its immunological dysfunction. The purpose of this study was to examine the effects of nutrition education promoting vegetable, fruit, and fish intake on the severity of AD in children. Children with AD aged 6 months to 5 years were randomly assigned into education and control groups, and followed for 1 year. Seventy-six children completed the study (38 for control, 38 for education). The education group received education promoting the intakes of antioxidant-rich foods (vegetables, fruits) and n-3 fatty acid foods (fish). A 24-hour food recall was collected for the diet information. After education, all vegetables (p < 0.001), fruits (p < 0.01), and fish (p < 0.05) intakes per 1000 kcal increased significantly in the education group, whereas only vegetable intake increased in the control group (p < 0.001). The SCORAD index, the severity of atopic dermatitis, decreased significantly in the education group (p < 0.05). Increased consumption of dietary vitamin E was significantly associated with reduction in the SCORAD index, after adjusting for age and gender (p < 0.05). A nutritional education program to increase vegetable, fruit, and fish intake may be effective in reducing the severity of AD, and vitamin E intake may be associated with the decreased severity of AD. More controlled studies on the relationship between these intakes and severity of AD, with intensive diet and/or supplement intervention programs, are needed to obtain conclusive results.