• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.4
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• pp.34-42
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• 2016

In order to prepare for the type approval test for the United States Coast Guard (USCG) Phase-II of Ballast Water Treatment System (BWTS), a phytoplankton mass culture was conducted in a mesocosm enclosure. We evaluated the response of the phytoplankton community after nutrient addition (+N, +P, and +NP) and investigated the development of the species with increasing culture time. After nutrient dosing, the phytoplankton population significantly (p < 0.05) increased from day 1 to day 3, depending on the nutrient treatments In particular, the specific growth rate of the phytoplankton community in the case of +NP treatment and + N treatment were estimated to be $2.47d^{-1}$ and $1.98d^{-1}$, respectively. The phytoplankton population density in the case of + NP treatment was approximately 50 times higher than that of the control group, suggesting that these treatments could be useful for mass culturing phytoplankton (> 75% of natural community) for the approval regulation of USCG Phase-II. In the phytoplankton community of the mesocosm, Pseudo-nitzchia spp. dominated in the logarithmic growth phase. The cell density decreased significantly (p < 0.05) with increasing time, coinciding with the nutrient limitation. At that time, the dominance of Pseudo-nitzchia spp. shifted to that of Cylindrotheca closterium. Therefore, the optimum nutrient concentration ($N:30{\mu}M$, $P:3{\mu}M$) and reasonable harvesting time (after 3 days in summer) found in this study for the mass culturing of phytoplankton may be helpful to meet the USCG Phase-II biological criteria to be used in BWTS.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.322-328
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• 2016

This study investigated the effects of temperature, salinity, and algal diet to find the optimal conditions for 5 days for the mass culture of the tropical tintinnid, Metacylis tropica. This tintinnid had a small, hyaline, and ovoid lorica. The oral diameter, length, and maximum width of the lorica were $36.7{\mu}m$, $49.5{\mu}m$, and $44.5{\mu}m$, respectively. In the temperature experiments, the highest maximum density and population growth rate were observed at $30^{\circ}C$ with 340.7 cells/mL and 1.1/day, respectively. Lower salinities adversely affected the population growth of M. tropica. The maximum density was observed at 33 ppt (840 cells/mL). In the diet experiments, M. tropica fed Isochrysis galbana showed the highest density (413 cells/mL) and population growth rate (1.2/day). As a result, M. tropica is appropriate as a potential prey organism for early fish larvae with smaller mouths because the tintinnid has a relatively small size compared to the rotifer. In addition, the conditions of $30^{\circ}C$, 33 ppt and supplying I. galbana would be effective in the cultivation of M. tropica.

• Ocean and Polar Research
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• v.42 no.2
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• pp.133-139
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• 2020

The aim of this study is to examine the physiological characteristics of an agarophyte Agarophyton vermiculophyllum (Ohmi) Gurgel, J.N. Norris et Fredericq in the early life stage of tetrasporophytes (2n) and gametophytes (n) to select appropriate seedlings for mariculture. Growth experiments were carried out at the combinations of four temperatures (20, 25, 30, and 35℃) and three light intensity levels (20, 60, and 100 µmol photons m^-2 s^-1) in the two ontogenetic stages: discoid holdfasts and erect sporelings. Holdfast areas and sporeling lengths of tetrasporophytes and gametophytes were estimated after 14 days in culture. Relative growth rates (RGRs) for holdfast areas were 7.08-28.38% day^-1 for tetrasporophytes and 11.58-23.67% day^-1 for gametophytes. At 35℃, holdfasts of tetrasporophytes survived with RGRs of 7.08-23.28% day^-1 but those of gametophytes died. Maximal holdfast growth of tetrasporophytes occurred at 30℃ and 100 µmol photons m^-2 s^-1, which were different from gametophytes (25℃ and 100 µmol photons m^-2 s^-1). RGRs of tetrasporophytic sporelings were 2.93-11.11% day-1 and were between 0.78-10.82% day-1 for gametophytes. Maximal growth of A. vermiculophyllum sporelings occurred at 25℃ and 60 µmol photons m^-2 s^-1 for tetrasporophytes, and at 20℃ and 100 µmol photons m^-2 s^-1 for gametophytes. In conclusion, the present results indicate that carpospores could be used as resources of spore-seedling methods having genetic diversity for mass field cultivation because tetrasporophytes showed higher-temperature tolerance and faster-growing ability than gametophytes of A. vermiculophyllum in the discoid holdfast and sporeling stages.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.54 no.1
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• pp.65-72
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• 2018

This study analyzed the condition of marine accident and disaster rate of crew of Korean fishing vessels by vessel type, and checked the Australian safety management system and relevant regulation in Korea to suggest measures to build coastal/offshore fishing vessel safety management system in Korean coastal/offshore fishery. As a result, the power and production amount of Korean coastal/offshore fishing vessel is consistently decreasing while marine accident is increasing. Disaster rate of crew was higher than land industry, especially, the disaster rate of coastal/offshore fishing vessel was very high (100.0‰). Australia applies safety management system differed by vessel type and operation waters which fully considers the characteristics of pertinent vessel. The average accident rate of fishing vessels with gross tonnage over 20 tons among the Korean coastal/offshore fishing vessel was 13.6%, which was significantly higher than fishing vessels with gross tonnage below 20 tons (1.4%). Such result indicates it is urgent to implement safety management system to fishing vessel with gross tonnage over 20 tons and introduce fishing vessel safety supervisor. Establishing safety management system of coastal/offshore fishing vessel will contribute to consistent industrial development by achieving the general goal of reducing marine accident and spreading safety culture.

• Journal of Navigation and Port Research
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• v.40 no.6
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• pp.431-440
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• 2016

This paper suggests facility planning ideas for recreational fishing complexes suitable for family anglers. Existing recreational fishing parks are only equipped with facilities for angling. There are many needs for recreational fishing complexes in coastal fishing villages that include not only angling facilities but also various marine leisure and sports facilities. In this paper we suggest concepts for recreational fishing complexes and define four types of complexes in terms of facilities planning. These four types of complexes are: 1) suburban leisure sports, 2) suburban healing and relaxation, 3) penturban experience and activities, and 4) penturban culture and recreation. Then we propose facility composition in detail for each type. Also we suggest site selection criteria for the village complex, facility infrastructure planning ideas, and leisure facilities (elementary and specialized) for recreational fishing complexes.

• Journal of Microbiology and Biotechnology
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• v.14 no.5
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• pp.906-913
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• 2004

A culture-independent molecular phylogenetic survey was carried out on the bacterial community in cold-seep sediment at Edison Seamount, south of Lihir Island, Papua New Guinea. Small-subunit rRNA genes were amplified directly from the sediment DNA by PCR and cloned. The majority of the cloned 16S rRNA gene sequences were most closely related to as-yet-uncultivated microorganisms found in deep-sea sediments, and were primarily affiliated with one of four groups: the $\gamma$-, $\delta$-, and $\epsilon$-subdivisions of Proteobacteria, and Cytophaga-Flavobacterium-Bacteroides. We did not recover any sequences related to cyanobacteria, prochlorophytes, and $\alpha$-Proteobacteria, which are known to occur in great abundance within the surface mixed layer of the Atlantic and Pacific Oceans. The majority of the cloned $\gamma$-and $\epsilon$-Proteobacterial sequences were closely related to chemoautotrophic sulfur-oxidizing symbionts of marine benthic fauna, and the $\delta$-Proteobacterial sequences to sulfate- and sulfur-reducing bacteria, indicating that they might play an important role in chemoautotrophic primary production and the sulfur cycle in the cold-seep area. There results demonstrate the high diversity of the bacterial community in the cold-seep sediment, and substantially expand knowledge of the extent of bacterial diversity in this formidable and unique habitat.

• Journal of Microbiology and Biotechnology
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• v.11 no.6
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• pp.1018-1023
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• 2001

Oleamide (cis-9-octadecenamide) is endogenous primary amide of fatty acid that is produced in small amounts in animal brains. It is known to induce sleep and to lower temperature by destroying the lipid plasma membrane structure of cells, thereby disclosing gap junction channels. To develop a new biological production method for oleamide, a screening program was conducted to isolate a microorganism producing oleamide. Among 1,500 soil microorganisms tested, KK90378 exhibited a potent positive reaction with Dragendoff`s reagent, used to detect the primary amide of oleamide. KK90378 was identified as a Streptomyces species based on cultural and morpohological characteristics, the presence of diaminopimelic acid in the cell wall, and the sugar patterns for the whole-cell extrat. Streptomyces sp. KK90378 produced oleamide 3 days after culture at $28^{\circ}C$, pH 7.2 A series of purification steps, including hexane extraction, silica gel column, and preparative thin layer chromatographies, were performed for the purification of oleamide. A spectrophotometric analysis using $^1H$, $^13C$-NMR, and GC-MS confirmed that the chemical structure of the purified oleamide was identical to that of authentic oleamide.

• Journal of Microbiology and Biotechnology
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• v.19 no.3
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• pp.257-264
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• 2009

A $\beta$-agarase gene, agaB34, was functionally cloned from the genomic DNA of a marine bacterium, Agarivorans albus YKW-34. The open reading frame of agaB34 consisted of 1,362 bp encoding 453 amino acids. The deduced amino acid sequence, consisting of a typical N-terminal signal peptide followed by a catalytic domain of glycoside hydrolase family 16 (GH-16) and a carbohydrate-binding module (CBM), showed 37-86% identity to those of agarases belonging to family GH-16. The recombinant enzyme (rAgaB34) with a molecular mass of 49 kDa was produced extracellularly using Escherichia coli $DH5{\alpha}$ as a host. The purified rAgaB34 was a $\beta$-agarase yielding neoagarotetraose (NA4) as the main product. It acted on neoagarohexaose to produce NA4 and neoagarobiose, but it could not further degrade NA4. The maximal activity of rAgaB34 was observed at $30^{\circ}C$ and pH 7.0. It was stable over pH 5.0-9.0 and at temperatures up to $50^{\circ}C$. Its specific activity and $k_{cat}/K_m$ value for agarose were 242 U/mg and $1.7{\times}10^6/sM$, respectively. The activity of rAgaB34 was not affected by metal ions commonly existing in seawater. It was resistant to chelating reagents (EDTA, EGTA), reducing reagents (DTT, $\beta$-mercaptoethanol), and denaturing reagents (SDS and urea). The E. coli cell harboring the pUC18-derived agarase expression vector was able to efficiently excrete agarase into the culture medium. Hence, this expression system might be used to express secretory proteins.

• The Korean Journal of Malacology
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• v.32 no.2
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• pp.119-125
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• 2016

The present study aimed to understand the effects of a ${\beta}$-glucan-added abalone feed (Immuneglu$^{TM}$) on the immune parameters, survival rate, and anti-bacterial activity of the abalone Nordotis discus hannai. During the study, spat and adult abalones were fed 0, 0.1, and 1% of Immuneglu$^{TM}$ mixed with artificial feed for 2 weeks, and their immune parameters, survival rate, and anti-bacterial activity were measured. The results showed that abalones fed on Immuneglu$^{TM}$-added feed showed a higher phagocytic rate, survival rate, and anti-bacterial activity against Vibrio alginolyticus, than those with the control treatment. In addition, the nitric oxide concentration, which indicates an inflammatory response, increased in the treatment group. Our study suggests that Immuneglu$^{TM}$ might be a useful additive for increasing the immunity and survival rates of abalones during mass culture.

• Proceedings of the KAIS Fall Conference
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• 2012.05a
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• pp.278-281
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• 2012

본 연구는 고주파를 발생시키는 고주파기기를 이용한 조류배양시스템에 관한 것으로, 미세조류 배양시 고주파 파형을 이용하는 것이다. 미세조류 배양을 위한 생물반응기에 200KHz~400KHz 고주파 파형이 나오도록 설계되었으며, Osillograph상에서 impedence가 최소가 되는 특정 지점에서 공명을 일으킬 때, 전기적 저항은 최소가 되며, 이상적인 고주파 파형 발생으로 생물반응기내의 미세조류의 Survival과 Growth에 직접적인 영향을 미치는 것을 확인하였다. 본 연구의 고주파 파형을 이용한 조류배양 시스템 개발은 자외선 흡수능을 높이는 조류배양에 활용될 수 있을 뿐만 아니라, 미세조류세포 내의 다양한 신호전달에 관련된 특정 피토케미칼, 펩타이드, 단백질 대사 연구에 유용하게 활용될 수 있다.