• Journal of Microbiology and Biotechnology
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• v.15 no.1
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• pp.197-201
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• 2005

A novel chitinase-producing bacterial strain of Pantoea dispersa was isolated from the sea near Bhavnagar, India for efficient disposal of chitinous waste from the seafood processing industry. The medium components were optimized by using a cubic model in the central composite design for increasing chitinase production. The optimal concentrations for higher production of chitinase were (g l-1) chitin, 10.0; urea, 0.35; MgSO4 7H2O, 0.08, and CaCl2, 0.15. Here, peptone (0.05 g l-1) was used as a constant variant in all trials. Using a statistical optimization method, the chitinase production was found to increase from 108 to 486.4 units ml-1. Chitin was prepared from the crustacean waste, and Fourier Transform Infrared (FTIR) Spectroscopy was used to characterize the isolated chitin. Chitinous waste degradation was studied in terms of chitinase production.

• Proceedings of the Korean Aquaculture Society Conference
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• 2005.05a
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• pp.76-77
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• 2005

• Fisheries and Aquatic Sciences
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• v.15 no.3
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• pp.255-257
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• 2012

The euphausiid crustacean Stylocheiron abbreviatum G. O. Sars, 1883 has been found in the southern waters of Jeju Island, Korea. This species is the third member of the genus Stylocheiron and the twelfth of the family Euphausiidae identified in Korean waters. Using descriptions of this species, a key to Korean euphausiids is presented.

• Journal of Aquaculture
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• v.18 no.1
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• pp.1-6
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• 2005

This study focused on spawning season, induce spawning, spawning and larval development of the Jicon scallop in Daehuksan Island of southwestern waters in Korea. The condition index and gonadosomatic index were used to investigate the reproductive pattern of the Jicon scallop. The major spawning season was from July to August, showing an unimodal gametogenic cycle per year. Several different tests were carried out to induce spawning of the mature male and female C. farreri. For females, the injection of serotonin, temperature induction technique and the combination of the both treatments produced significantly faster gamete release. Unlike females, males spawned only in response to the UV rays irradiation stimulation. Mean size of fertilized eggs was 69.5 $\mu$m in diameter. After fertilization, the zygote could be divided into 2 cells as early as 2 hours. It took about 8 hours to develop the 8-cell stage, about 20 hours to hatch trochophore larvae, and about 40 hours to be D-shaped larvae.

• Journal of Korean Society on Water Environment
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• v.28 no.2
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• pp.313-319
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• 2012

Various nanomaterials may flow into the aquatic ecosystem via production, use, and treatment processes. Especially, gold nanoparticles (AuNPs) were categorized as manufactured nanomaterials presented by the Organization for Economic Cooperation and Development Working Party on Manufactured Nanomaterials (OECD WPMN) in 2010. AuNPs have been used in medical area, however, they were reported to induce cytotoxicity and oxidative DNA damage, as well as down-regulation of the DNA repair gene in mice and human cell lines. In this study, the aquatic toxicity data of AuNPs and gold ions were collected, with the specific test methods analyzed with respect to the form and size of AuNPs, test species, exposure duration, and endpoints. Currently, aquatic toxicity data of AuNPs and gold ions have been presented in 14 studies including 4 fish, 6 crustacean, 2 green algae, and 2 macrophytes studies, as well as a further 8 studies including 4 fish, 4 crustacean, 1 platyhelminthes, and 1 green algae, respectively. The AuNPs were 0.8-100 nm in size, as gold nanoparticles, gold nanorod, glycodendrimer-coated gold nanoparticles, and amine-coated gold nanoparticles. The tested endpoints were the individual toxicities, such as mortality, malformation, reproduction inhibition, growth inhibition and genetic toxicity such as oxidative stress, gene expression, and reactive oxygen species formation. The accumulation of AuNPs was also confirmed in the various receptor organs. These results are expected to be useful in understanding the aquatic toxicity of AuNPs and gold ions, as well as being applicable to future toxicity studies on AuNPs.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.3
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• pp.248-253
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• 2018

Freshwater farms are primarily located adjacent to rivers and lakes, facilitating the introduction and spread of pathogens into natural systems. Therefore, it is necessary to continuously monitor natural aquatic organisms, the breeding environment, and infection rates by pathogenic organisms. Fish and crustaceans were sampled 4 times in the Geum River estuary in 2016. The samples were analyzed for the presence of pathogens for reportable communicable diseases, including KHVD (koi herpesvirus disease), SVC (spring viraemia of carp), EUS (epizootic ulcerative syndrome) and WSD (white spot disease); parasite abundance was also examined. The dominant fish species were deep body bitterling Acanthorhodes macropterus (21.4%), followed by skygager Erythroculter erythropterus (12.7%). For crustaceans, Palaemon paucidens and Chinese mitten crab Eriocheir sinensis were dominant. Sixty fish and 36 crustacean species were examined for reportable communicable diseases. When using a specific primer set for each disease, PCR analysis did not detect any reportable communicable diseases in the samples. Some instances of Dactylogyrus, copepods, nematodes and metacercaria were detected. However, the PCR results indicated that the metacercaria were not Clonorchis sinensis.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.6
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• pp.654-658
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• 2010

The purpose of this study is to establish methods for enhancing the survival and growth of cold-water fish and crustacean larvae based on the nutritional components of zoo and phyto live foods. Rotifers, Brachionus rotundiformis, were cultured with a supplement of freshwater condensed Chlorella vulgaris at $28^{\circ}C$ and enriched with Algamac $2000^{(R)}$ at 16, 20 and $26^{\circ}C$, respectively. Isochrysis galbana, Chaetoceros calcitrans and Chlorella ellipsoidea were centrifuged for component analysis after being cultured for approximately one week with conway medium at $20^{\circ}C$. The crude protein and lipid contents of the rotifers were 58.4% and 10.9%, respectively, before enrichment. After enrichment at each temperature, total protein and essential amino acid contents were increased by reducing the enrichment temperature. However, unsaturated fatty acids and multiple fatty acid index (UI) showed their highest values at $20^{\circ}C$. Mono-unsaturated fatty acid content was highest (72.6%) at $16^{\circ}C$. The total protein contents of C. calcitrans and C. ellipsoidea were higher, 33.0% and 35.2%, respectively, than that of I. galbana, 27.8%. Methionin, leusine and histidine, essential amino acids of C. ellipsoidea, had considerably higher values, 50.2, 287.2 and 68.1 mg/g dry matter, respectively, compared to other microalgae. Total lipids, UI, DHA and n-3 PUFA of I. galbana had higher values, 23.6, 272.0, 12.9% and 45.2%, respectively, than other microalgae. Therefore, for cold-water fish and crustacean larvae that require high n-3 PUFA and DHA contents, enrichment of rotifers is desirable at $20^{\circ}C$. Fish larvae would also need more I. galbana than other microalgae.

• Animal Systematics, Evolution and Diversity
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• no.nspc3
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• pp.139-146
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• 1992

The primary sequence of the 18S rRNA gene of a crustacean Pugettia quadridens (Decapoda: Pleocyemata: Brachyura) was determined by the PCR cloning and Taq sequencing. The 18S rRNA gene of this species in 1837 bases long, and 46 bases shorter than that of another crustacean decapod Oedignathus inermis. The similarity between two species is 90.8% when the insertion and/or deletion sites were excluded. Within the molecule, the most conservative (identical) region locates at the position of 1137-1206 and it is 70 bases long. The most long consecutive nucleotide differences occur at the position between 46-55 and the second most between 399-407. The sequence variation in the primary structure of 18S rRNA gene are not evenly distributed throughout the molecule.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.46 no.4
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• pp.324-334
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• 2010

This investigation was carried out to research on the actual states for bycatch and discards of catches caught by funnel net from December, 2007 to June, 2010. Fishing grounds were Manheung-dong and Ocheon-dong in the coastal waters of Yeosu. The number of the investigation was 21 in Manheung-dong and 7 in Ocheon-dong fishing ground. In Manheung-dong, the species of catches were 26 of fish, 6 of cephalopod and 5 of crustacean. In Ocheon-dong, the species of catches were 25 of fish, 6 of cephalopod and 4 of crustacean. In the two all fishing grounds, the largest amount of species was revealed as gray mullet. Among these catches, the number of non marketable species that were classified and discarded ones, were 9 in Manheung-dong and 7 in Ocheon-dong. Also, among the marketable species which were small entity or too tiny catches to commercialize and not fresh ones were discarded. The proportion that they dominate in the whole catches was 37.1% in the number of catches and 5.4% in the weight of catches in Manheung-dong, and 6.9% in the number of catches and 0.3% in the weight of catches in Ocheon-dong. In case of Manheung-dong, the monthly discarding proportion was the highest with 59.4% in the number of catches in may and 17.6% in the weight of catches in November, and in case of Ocheon-dong, the both of them were the highest in February, with 28.0% in the number of catches and 5.1% in the weight of catches.

• Journal of Marine Life Science
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• v.5 no.2
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• pp.35-42
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• 2020

17β-estradiol (E₂) is a natural hormone secreted by ovary, and continuously discharged from household and livestock wastewater into aquatic environment. Due to its strong estrogenic activity, it has adverse effects on development and reproduction in crustacean as an endocrine disrupting chemical. Although ecdysteroid signaling pathway play a key role in development in crustacean, little information on transcriptional modulation of ecdysteroid-related genes in response to E₂ is available in small crustacean. Here, we investigated the acute toxicity of E₂ to obtain 24-h LC_x values in the brackish water flea Diaphanosoma celebensis. Time-dependent expression patterns of seven ecdysteroid pathway - related genes (CYP314a1, EcRA, EcRB, USP, ERR, Vtg, VtgR) were further examined using quantitative real time reverse transcriptase polymerase chain reaction (qRT-PCR). As results, 24-h LC₅₀ and LC₁₀ values were 9.581 mg/l and 4.842 mg/l, respectively. The mRNA expression of CYP314a1, EcRA, USP, VtgR was significantly up-regulated at 12 or 24 h after exposure to E₂. These findings indicate that E₂ can affect their molting and reproduction by modulating the expression of ecdysteroid pathway - related in D. celebensis. This study will be useful for better understanding of molecular mode of action of endocrine disrupting chemicals on molting process in small crustacean.