• Fisheries and Aquatic Sciences
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• v.15 no.1
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• pp.21-27
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• 2012

Ground seawater in the east area of the volcanic Jeju Island contains abundant minerals. We investigated the metabolic activity of electrodialyzed, desalted ground seawater (EDSW) from Jeju in both cultured cells and animals. The addition of EDSW to the culture medium (up to 20%, v/v) reduced the leakage of lactate dehydrogenase and increased MTT activity in CHO-IR cells. EDSW (10%) promoted insulin-induced glucose consumption in L6 muscle cells as well as the activities of the liver ethanol-metabolizing enzymes, alcohol dehydrogenase and aldehyde dehydrogenase. Moreover, EDSW suppressed palmitate-induced intracellular fat accumulation in human hepatoma $HepG_2$ cells. Activities of AMP-stimulated protein kinase and acetyl CoA carboxylase, enzymes that modulate fat metabolism, were altered by EDSW in $HepG_2$ cells toward the suppression of intracellular lipid accumulation. EDSW also suppressed hepatic fat accumulation induced by a high-fat diet in mice. Taken together, EDSW showed beneficial metabolic effects, including the enhancement of ethanol metabolism and insulin-induced glucose consumption, and the suppression of intrahepatic fat accumulation.

• Fisheries and Aquatic Sciences
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• v.26 no.11
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• pp.649-659
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• 2023

The present study compared the structure of mixilliped of Fenneropenaeus chinensis between the larval and adult stage and investigated the effect of the structural difference on the immunity of F. chinensis. A fourteen day and a one-month long culture trial were conducted each with postlarvae and adults of F. chinensis in the biofloc, mixed water (50% biofloc:50% clear seawater) and seawater control. Immune-related genes mRNA expressions of postlarvae was analysed by quantitative reverse transcription polymerase chain reaction (qRT-PCR). And the analysis of adult stage immunity was carried out using phenoloxidase (PO) enzyme activation in haemocyte. In the postlarvae, the final body weights were 51.43 and 58.47 mg for the biofloc water and the control seawater, respectively. On the other hand, the final body weights of the adults were significantly different between biofloc water and seawater. The survival rate showed the opposite trend to the growth rate. Immune related genes mRNA expression levels in the postlarvae in the biofloc water were significantly lower than those in the seawater. While, the adult stage showed significantly higher PO enzyme activations in the biofloc water than in the seawater with the PO enzyme activation increasing proportionally to the biofloc concentration. This result is considerably explained by the observations of setal morphological structures of the third maxilliped: postlarvae have short serrulated setae that compose the small 'net' structure while adults had long and dense plumose setae. It is understood that the morphological difference of the maxilliped structure resulted in the different feeding abilities in the postlarvae and the adult F. chinensis to use bioflocs as food source.

• Development and Reproduction
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• v.28 no.3
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• pp.75-86
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• 2024

Artificial sexual maturation of eel (Anguilla japonica) involves rearing in seawater and injecting salmon pituitary extract (SPE). The salinity of seawater and components of SPE influence hormonal activities of the eel pituitary, leading to gonad development. This study investigated the direct effects of salinity change and SPE treatment on the eel pituitary gland using primary cell cultures. Pituitary cells were cultured into four experimental groups: control culture (control), SPE-treated culture (SPE), NaCl-treated culture (NaCl) and NaCl+SPE NaCl+SPE treated culture (NaCl+SPE). We investigated the expression of genes presumably related to reproduction and/or salinity, including luteinizing hormone (LHβ), follicle stimulating hormone (FSHβ), progesterone receptor-like (pgrl), prolactin (PRL), dopamine receptor D4 (drd4), neuropeptide B/W receptor 2 (NPBWR2) and relaxin family peptide receptor 3-2b (rxfp3-2b). Gene expression analysis revealed significant upregulation of LHβ in SPE and NaCl+SPENaCl+SPE groups compared to control and NaCl (p<0.05). FSHβ expression did not show any significant changes. PRL showed a significant decrease in the NaCl group (p<0.05). Pgrl, NPBWR2, drd4, and rxfp3-2b displayed the highest expression in the control group, with downregulation observed in all treatment groups (NaCl, SPE, and NaCl+SPE) (p<0.05). This study demonstrated the direct effects of salinity changes and SPE treatment on the eel pituitary. Results from this study also suggest that salinity change is necessary but work together with SPE to induce reproductive process, and that LHβ, pgrl, PRL, drd4, NPBWR2, and rxfp3-2b genes are obviously associated with reproduction and salinity changes in eels.

• The Korean Journal of Malacology
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• v.31 no.2
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• pp.129-136
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• 2015

To introduce an oyster rack culture in tidal flat of Wando-gun, Korea, we investigated sanitary conditions from 2012 April to 2013 March in oyster growing waters and adjacent area in Wando. Average seawater temperature and salinity ranged $8.6-28.0^{\circ}C$ and 26.2-33.6 psu, respectively. The coliform group and fecal coliform of seawater ranged < 1.8-13.0 MPN/100 mL each. Only one of 60 samples was exceeded in the European criteria of fecal coliform. Influence of adjunct basin's pollution load on cultural waters was negligible, which half radius of dilution was not above 300 m. According to our observation, however, landing of oyster should be banned for at least 5 days after the heavy rainfall. Our findings meet the sanitary seawater criteria for domestic use and export of shellfish and classified as 'Class A' in European Community regulations for bivalve culture.

• Journal of Bio-Environment Control
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• v.11 no.4
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• pp.181-187
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• 2002

The overall objective of this study was to improve tomato fruit quality, while maximizing yield. The variety of 'Momotaro' was grown in the basic nutrient solution of 1.6 dS.m$^{[-10]}$ which was supplemented by three levels of seawater with EC 1.0, 2.0 or 3.0 dS.m$^{[-10]}$ . Tomato plants were cultivated in cool seasons. Plant growth characteristics were compared between treatments, and fruits were classified to analyse fruit quality characteristics according to ripening stages： MG, Br, Br＋3, Br＋5, Br＋7 and Br＋10. Adding seawater generally did not affect the shoot growth parameters such as plant height, leaf length, leaf width, internode length and chlorophyll content. Adding seawater negatively affected yield parameters such as the height and weight of fruit, marketable fruit weight per plant and marketable fruit yield. Therefore, the more yield reduction was obtained with the increasing level of seawater treatment. Fruit quality was improved by seawater treatment. The degree of the effect for $^{\circ}$Bx degree and sugars were the highest with the EC of seawater 2.0~3.0 dS.m$^{[-10]}$ , and at the Br＋5~Br＋7 of ripening stages. The relative abundance of tomato flavor, volatile components, was not generally affected by the seawater treatment with an exception of 6-methyl-5-hepten-2-one. The relative abundance of most volatile components increased as ripening progressed. The increment began at the Br stage and showed the highest increment at the Br＋5~Br＋7 stages. The results from these experiments suggest that seawater treatment of EC 3.6 dS.m$^{[-10]}$ for hydroponics is good for improving tomato quality. Fruit quality is the best at the Br＋5~Br＋7 ripening stages. It is considered that these results may be applied far use in hydroponic culture to improve fruit quality with minimum yield reduction.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.2
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• pp.155-159
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• 1999

Marine bacteria inhibiting the growth of the diatom, Chaetoceros calcitrans were screened from seawater samples collected at south coast of Korea in 1996. Six strains were isolated from those samples. Among them, a bacterium SR-14 strain had the strongest inhibition activity against the alga. The selected SR-14 strain was identified as an Alteromonas sp. (supposed to be Alteromonas colwelliana) according to its biochemical results. Alteromonas sp. SR-14 was able to grow in raw seawater, aged seawater, Conwy medium for culture of microalgae and C. calcitrans culture filtrate. The host ranges of Alteromonas sp. SR-14 were C. calcitrans, C. muclleri and C. negracile among 10 species of diatom. All of the Chaetoceros spp. tested were inhibited by the Alteromonas sp. SR-14, However, the growth of the other genera in Bacillariophyceae was not inhibited.

• Journal of the Korean Society of Food Culture
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• v.34 no.2
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• pp.129-141
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• 2019

The modernization process of Korea, which can be considered westernization, has influenced Korean folk culture. In this process the kimchi culture could be destroyed. However the kimchi culture has survived very well to date. This study was conducted to investigate the cause of this survival of the kimchi culture. To accomplish this, the enormous influence of modernization on kimchi culture and the cause of its successful survival was investigated in the middle region of the Korean peninsula. We think that the kimchi culture can survive because of the inherent system and structure. Kimchi is composed of vegetables, salt, seasoning, and salted seafood (jeotgal), which are systemized. We also described the kimchi ethnography in this region to study the regional characteristics. The eastern coast uses a different method to salt the cabbage during the production of Kimchi, namely it uses seawater to accomplish this. Additionally, pollak broth is used instead of jeotgal. However nowadays the regional uniqueness of kimchi culture has greatly disappeared in large part, and Korean kimchi is standardized in this region.

• Ocean and Polar Research
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• v.26 no.1
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• pp.102-111
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• 2004

Recirculating aquaculture system (RAS) consists of different treatment compartments that maintain water quality within the ranges commonly recommended for fish cultures. However, common RASs still exert considerable environmental impact since concentrations of organic matter and nutrients in their effluents are high. Compared with the traditional RAS, the model RAS developed here use a sedimentation basin for digestion purposes and then use the released volatile organic matter to stimulate a denitrification process. Different treatment compartments for solids, total ammonia nitrogen, and nitrate removal have been reviewed. This paper provides the basic information on designing different treatment compartments as well as the engineering criteria in closed seawater RAS, consisting of circular tanks for fish cultures; dual drain systems, sedimentation basins and foam fractionators for removal of solids; nitrification biofilters for TAN removal; denitrification biofilters for nitrate removal; and aerators for aeration. The main purpose is to outline a common procedure in designing of closed RAS for marine fish culture with an emphasis on easy management and low expense, as well as reduction of the environmental impact.

• Journal of Environmental Science International
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• v.18 no.11
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• pp.1283-1289
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• 2009

Eco-physiological research and the control of Cochlodinium polykrikoides was carried out to elucidate eco-physiological characteristics of red tide organism through culture experiment depending on the condition of photon irradiance. Oxygen consumption of C. polykrikoides was high with a value of 1.12 mg/L/hr in the dark compared with that of 0.13 mg/L/hr at $100{\mu}mEm^{-2}s^{-1}$. DO values in a circular chamber with the lapse of time in seawater containing C. polykrikoides were declined in the dark period. DO values of seawater containing C. polykrikoides in the dark were declined from 7.01 mg/L to 2.65 mg/L in 30 cm depth and from 7.01 mg/L to 6.63 mg/L in 5 cm depth depending on the depth of circular culture vessel. Olive flounder, Paralichthys olivaceus and file fish, Stephanolepis cirrhifer exposed to Cochlodinium showed the separation of the lamella epithelium from gill filament, which disrupted the respiratory process at the gill level.

• ALGAE
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• v.24 no.3
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• pp.163-168
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• 2009

Grateloupia filicina (J.V. Lamouroux) C. Agardh (Halymeniaceae, Cryptonemiales, Rhodophyta) is an edible seaweed as well as an important source of carrageenan. In the present study, attempt has been made to develop a suitable protocol for effective regeneration of the seaweed and the rapid multiplication of the desired varieties. The young upright thallus of G. filicina was grown in axenic culture using both solid and liquid media. The various media tested were f/2, Provasoli’s Enriched Seawater (PES) and Enriched Seawater (ESW). The effect of glycerol (as a carbon source) and various plant growth regulators i.e. auxin (NAA) and cytokinins (Kinetin and BA) were tested. Although, regeneration of young thalli was observed from the cut ends in all the media, better growth was found in f/2, PES, f/2 (0.5% Glycerol), f/2 (NAA ${10^{-5}}_M)\;and\;f/2\;(BA\;{10^{-6}}_M$). On the other hand callusing was observed only in solid media supplemented with low concentration of Glycerol (0.5%) in f/2, NAA ${10^{-5}}_M\;in\;f/2,\;PES\;and\;BA\;{10^{-5}}_M$ in f/2. Young thalli were developed from the callus sub culture after 40 days of inoculation.