• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.11a
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• pp.164-165
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• 2005

As MSOA(organism activity measurement system) is a system that measure organism's activities using the 455[kHz] supersonic transducer, it's composed to MCM(main control module), LDM(loop design module) and CMM(control and monitoring module). The purpose of this research is to confirm the effectiveness of supersonic measurement in organism activity as comparison with organism's respiration measurement using oxygen meter.

• Microbiology and Biotechnology Letters
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• v.46 no.2
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• pp.127-134
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• 2018

In this study, 79 bacterial isolates were collected from the surface of marine algae Umbraulva japonica. As a result of analysis of 16s rRNA gene sequence, the 79 isolated bacteria were divided into 4 major groups: [Proteobacteria (74.69%), Actinobacteria (2.53%), Fimicutes (2.53%), and Bacteroidetes (20.25%)] - 7 classes (Actinobacteria, Flavobacteria, Sphingobacteria, Baciili, Alphaproteobacteria, Betaproteobacteria, and Gammaproteobacteria), 12 orders, 17 families and 31 genera. The newly isolated 3 strains could be novel species because of less than 97% similarity in 16s rRNA sequence. Therefore, it is considered that additional experiments should be conducted together with the standard strain. Analysis of 79 bacterial antibacterial activity against human and fish pathogens, such as Edwardsiella tarda, Vibrio harveyi, Streptococcus iniae, Steptococcus parauberis, Escherichia coli, Steptococcus mutans, Listeria monocytogenes and Vibrio vulnificus, was performed by using the supernatant liquid and pellet. As a result, pellet of UJT9, UJT20 and UJR17 showed antibacterial activity against V. vulnificus, UJR17 also showed antibacterial activity against S. parauberis. UJT7 and UJT20, UJR17 have been identified as Bacillus sp. and Pseudomonas sp. and it may be safely assented that it's beneficial to carry out additional experiments for various applications.

• Korean Journal of Microbiology
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• v.51 no.4
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• pp.382-388
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• 2015

Eleven protease-producing bacteria were isolated from the organisms' external shells and the inorganic materials collected from intertidal zone of Jeju Island, Republic of Korea. The samples were diluted serially, inoculated on Zobell agar plates with 1% skim milk and incubated at $20^{\circ}C$. Clear zone forming colonies were selected as protease-producing bacteria and each strain was identified based on the phylogenetic analysis with their 16S rDNA sequences. Strains JJM125, JJM129, YG47 and YG49 belong to the marine bacterial genus Pseudoalteromonas; strain JJM122 belong to the genus Microbulbifer; strains YG51, YG52, YG62 and YG63 belong to the genus Vibrio; and strain YG65 belong to genus Bacillus. Hence, the present study suggests that these protease producing bacteria could be further used to develop new varieties of protease with various biotechnological applications.

• Journal of fish pathology
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• v.22 no.3
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• pp.317-326
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• 2009

This study has shown the screening of anti-bacterial activity of three Indian medicinal plant choloroform : methanol (50:50) solvent leaf extracts (i.e. Azadirachta indica, Ocimum sanctum, and Curcuma longa) with different concentrations (10, 5, 2.5, 1.25, 0.625, 0.312, and 0.156 mg/ml) under in vitro conditions against fish pathogenic bacteria, Aeromonas hydrophila, Streptococcus iniae, Vibrio harveyi, V. anguillarum, and Edwardsiella tarda isolated from olive flounder farms, Jeju Island, South Korea. The anti-microbial activity of the A. indica and O. sanctum extracts yielded the zones of growth inhibition (ZI) was 3 and 1mm against A. hydrophila at concentration of 0.156 mg/ml when compared to that of tetracycline standard (3 mm). At highest concentration (10 mg/ml) of A. indica, O. sanctum, and C. longa, high inhibition was 9, 7, and 6 mm when compared to that of tetracycline (11 mm) against A. hydrophila. The minimum inhibitory concentration (MIC) of A. indica, O. sanctum, and C. longa at 0.156 mg/ml that yield 9, 10, and 13 CFU/ml for A. hydrophila, 16, 22, and 25 CFU/ml for S. iniae and 18, 22, and 23 CFU/ml for E. tarda compared to the tetracycline. At highest concentration (10 mg/ml) of the three extracts was better inhibiting the growth of A. hydrophila, S. iniae and E. tarda. A. indica, O. sanctum, and C. longa were determined to the potential antioxidant activityon the basis of their scavenging activity of the stable 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical. A. indica extract was 0.625 mg/ml which indicated that the strong anti-oxidant activity. However, O. sanctum and C. longa extracts showed weak anti-oxidant activity at this concentration. Hence, in vitro assay among the pathogens, A. hydropila is better inhibitory activity of the extracts. It is evident that the Indian medicinal plants extracts were subjected to its effectiveness against A. hydrophila, S. iniae, and E.tarda at low concentrations. The obtained results in the present study suggested that the Indian plant extracts is a prevention tools for Korean olive flounder aquaculture pathogens and its need further advance investigation.

• Food Industry And Nutrition
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• v.18 no.1
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• pp.8-12
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• 2013

• Natural Product Sciences
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• v.18 no.2
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• pp.102-105
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• 2012

Marine organism extracts were prepared from 26 species of Korean indigenous marine organisms, including 25 species belonging in class Anthozoa of phylum Cnidaria and a species belonging to subphylum Urochordata of phylum Chordata, and screened their inhibitory effects against ${\mu}$-calpain. As a result, the thirteen extracts were found to be active in the criteria of $IC_{50}$ < 100 ${\mu}g/ml$. Among them, the MeOH extracts of Plexauroides praelonga and Alveopora japonica showed remarkable ${\mu}$-calpain inhibitory activity with $IC_{50}$ values of $4.62{\pm}0.22$ and $4.82{\pm}0.07{\mu}g/ml$, respectively. In addition, chemical investigation of A. japonica led to the isolation of an active compound, hexadecyl tetradecanoate, as a selective cathepsin B inhibitor ($IC_{50}=9.05{\pm}2.45{\mu}M$). This compound was isolated as constituent of A. japonica for the first time in the present study.

• Journal of Life Science
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• v.26 no.11
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• pp.1308-1312
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• 2016

Heavy metals such as gallium (Ga) cause serious physiological damage to exposed organisms, mostly of aquatic species. Ga one of the inter-metallic, transition elements increasingly being used in making high-speed semiconductors, such as Ga arsenide. The purposes of this study were to investigate the effects of Ga on acute toxicity, serum biochemical changes, and erythrocyte morphological changes in the blood stream of goldfish (Carassius auratus). Median lethal concentrations were determined in acute tests. The 96 hr $LC_{50}$ value was 9.15 mg/ml. Goldfish were exposed to different Ga concentrations (2.0, 4.0, and 8.0 mg/ml) for 30 days to assess its toxic effects. The results indicate that the measured serum biochemistry parameters (including glucose, blood urea nitrogen, creatinine, cholesterol, and triglyceride) of the Ga-exposed fish groups differed significantly from the untreated fish group. In addition, a change in the erythrocytes' morphology at a high concentration (8.0 mg/ml) of Ga exposure shows respiratory problems. Our results suggest that 2.0 mg/ml is proposed as a biologically safe concentration that can be used for establishing tentative water quality criteria concerning the same-size goldfish.

• Journal of Environmental Science International
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• v.14 no.2
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• pp.121-128
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• 2005

Hexachlorobenzene (HCB) was analyzed in various marine organisms of Korea. HCB was detected in all organism samples with residual concentrations from 0.51 to 222 pg/g wet weight. HCB residue was the highest content in crustacean, and followed by bivalves, fish, cephalopods and gastropods. The residues were comparable to or lower than those in marine organisms of other countries. Daily dietary intake of HCB from seafood was estimated to be 13.4 pg/kg body weight/day. The relative contribution of taxonomic group to the total dietary intake of HCB were in the order of crustaceans $(40.1\%)$, bivalves $(34.2\%)$, fish $(23.1\%)$, cephalopods $(2.22\%)$, and gastropods $(0.38\%)$. Daily dietary intake of HCB expressed as toxic equivalent (TEQ) value was estimated to be $1.34\times10^{-3}pg$ TEQ/kg body weight/day. This value did not exceed tolerable daily intake (TDI) proposed by the WHO, the UK toxicity committee and the KFDA. Cancer risk and target hazard quotient (THQ) due to the consumption of the marine organism in Korean adult population were evaluated using the exposure equation of food ingestion. This result suggests that dietary intake of HCB by the consumption of Korean seafood seems to be safe for human health with negligible cancer and non-cancer risks so far.

• Journal of Korean Society of Disaster and Security
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• v.11 no.1
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• pp.1-5
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• 2018

Power plant is the important infrastructure to generate electricity. This plant in normally located next to river and seashore in order to take cooling water through intake. However, the plant is stopped when marine organism blocks the intake, and it caused damages by social and commercial. Therefore, air bubble barrier has been used to block marine organism in order to operate the plant properly. The aim of this study was to test the rates of cut off of floating substance by air bubble barrier to develop the facility for the plant. The test was conducted by current velocity, pressure of air, specific gravity of the substance and the layer of the barrier, and the result showed the blocking rates by the condition. It will be used as basic data to develop the air bubble barrier and to operate power plant properly from the marine organism.

• Microbiology and Biotechnology Letters
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• v.45 no.3
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• pp.250-256
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• 2017

The prevalence of infections due to pathogenic bacteria such as Edwardsiella tarda, Streptococcus parauberis, and Photobacterium phosphoreum in fish farms in Jeju Island and their management by marine-derived biomaterials was studied. In this study, we isolated eight spices type of marine-derived biomaterials from four sea areas of Jeju Island. An antibiotic disc susceptibility test confirmed that the isolated marine-derived biomaterials showed weak resistance only to oxytetracycline and penicillin and sensitivity to the other antibiotics tested, and antimicrobial activity against fish pathogens with the inhibitory zone of 22 mm, 18 mm, and 19 mm for MD-02, MD-04, and MD-06 against E. tarda strains, respectively, and 19 mm, 22 mm, 30 mm, and 29 mm for MD-01, MD-02, MD-04, and MD-06 against S. parauberis strains, respectively, while all the marine-derived biomaterials showed antibacterial activity against P. phosphoreum. Among the eight biomaterials selected, Bacillus subtilis MD-02 displayed the greatest antibacterial activity against the three tested fish pathogens and also displayed susceptibility to antibiotics. The growth of Bacillus subtilis MD-02 was greatest with the carbon source, dextrine; nitrogen source, peptone; and mineral source, $MgSO_4{\cdot}7H_2O$. Hence, the present study confirmed that the isolate B. subtilis MD-02 from Jeju Island could be a potential antimicrobial agent against fish pathogens and a potential pharmacotherapeutic agent.