• BMB Reports
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• v.39 no.4
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• pp.346-354
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• 2006

The full-length cDNA of grass carp (Ctenopharyngodon idellus) and silver carp (Hypophthalmichthys molitrix) uncoupling protein 2 (UCP2) was obtained from liver. The grass carp UCP2 cDNA was determined to be 1152 bp in length with an open reading frame that encodes 310 amino acids. Five introns (Intron 3, 4, 5, 6 and 7) in the translated region, and partial sequence of Intron 2 in the untranslated region of grass carp UCP2 gene were also obtained. Gene structure comparison between grass carp and mammalian (human and mouse) UCP2 gene shows that, the UCP2 gene structure of grass carp is much similar to that of human and mouse. Partial UCP2 cDNA sequences of bighead carp (Aristichthys nobilis) and mud carp (Cirrhinus molitorella), were further determined. Together with the common carp (Cyprinus carpio) UCP2 sequence from GenBank (AJ243486), multiple alignment result shows that the nucleotide and amino acid sequences of the UCP2 gene, were highly conserved among the five major Chinese carps that belong to four subfamilies. Using beta-actin as control, the ratio UCP2/beta-actin mRNA (%) was determined to be $149.4{\pm}15.6$ (common carp), $127.4{\pm}22.1$ (mud carp), $96.7{\pm}12.7$ (silver carp), $94.1{\pm}26.8$ (bighead carp) and $63.7{\pm}16.2$ (grass carp). The relative liver UCP2 expression of the five major Chinese carps, shows a close relationship with their food habit: benthos and detrituseating fish (common carp and mud carp) > planktivorious fish (silver carp and bighead carp) > herbivorious fish (grass carp). We suggest that liver UCP2 might be important for Chinese carps to detoxify cyanotoxins and bacteria in debris and plankton food.

• Microbiology and Biotechnology Letters
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• v.44 no.4
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• pp.535-539
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• 2016

The prevalence of pathogenic bacteria such as Streptococcus parauberis (Sp), Streptococcus iniae (Si), and Edwardsiella tarda (Et) in flounder fish farms in Jeju Island and their management by gallium treatment was studied. Sp, Si, and Et were found to exhibit a low rate of cell growth and high biofilm formation. Hence, in the present study, cell growth and biofilm formation were measured spectrophotometrically 72 h after the addition of different concentrations of gallium (2, 4, or 8 mg/ml). In addition, cell death was measured by resazurin and propidium iodide staining assays. The results showed that bacterial cell death increased and biofilm formation decreased with an increasing concentration of gallium. Hence, the present study signifies that the use of gallium against bacterial pathogens could be useful for disease management in flounder farms.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.1
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• pp.1-7
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• 1997

In order to utilize fish by-products from the skipjack tuna (Katsuwonus pelamis) canning manufactures Lactobacillus buigaricus KCTC 3188 and L. piantarum KCTC 1048 were used as a starter culture for the preparation of fermented fish silage with skipjark tuna viscera. The optimum temperature and pH on barterial growth and lactic acid production of L. bulgaricus and L. plantarum in MRS broth were $35^{\circ}C$ and around pH 6.0, respectively. And the optimum concentrations of the carbohydrate sources added to the broths were $7\%$ for dextrose and $10\%$ for molasses on the basis of total weights of skipjack tuna viscera. The pH of acid treated skipjack tuna viscera silage (ASS) slightly increased from 4.0 to 4.5, while that of fermented skipjack tuna viscera silages by the use of lactic acid bacterias (FSS) was significantly declined from 5.9 to about 40 after 42 days of storage at $35^{\circ}C$. Though the content of volatile basie nitrogen (VBN) in ASS was lower than those of FSS after 42 days of storage at $35^{\circ}C$, VBN content in silages slightly increased from an initial value of $62\~65{\cdot}mg/100g$ to final value of $113\~155\;mg/100g$ over 42 days. The fermented silage by L. piantarum reached a maximum concentration of amino nitrogen and showed $81\%$ of hydrolysis degree after 4 days of storage at $35^{\circ}C$.

• Journal of fish pathology
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• v.14 no.2
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• pp.71-80
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• 2001

The purpose of this study was to investigate the microbiological characteristics and the distributions of the bacteria causing streptococcicosis occurred in marine fish farm, Korea. Many kinds of cultures fishes suffered from the disease accompanied with typical symptoms, including darkening of the skin, exophthalmia, petechiae inside of the opercula and distended abdomen. The isolates from the diseased fishes were compared with Lactococcus garvieae by biochmical, biophysical and serological methods and polymerase chain reaction(PCR) assay. We isolated 35 strains of the geuns Streptococcus from the diseased olive flounder, Paralichthys olivaceus, yellow tail, Seriola quinqueradiata and Korean rockfish, Sebastes schlegeli. 15 strains out of the isolates were identified to L. garvieae and the others were not because of their different biochemical and biophysical charateristics. Seven strains of the isolates were agglutinated by rabbit serum raised against L. garvieae $KG^+$ phenotypic cells(ATCC49156)as a reference strain. Twenty-one strains of the isolates identified to L. garvieae since they were formed the expected band through performing PCR assay using specific primers, pLG-1(5'-CATAACAATGAGATCGC-3') and pLG-2(5'-GCACCCCGCGGTTG-3'). In the present study, it showed that L. garvieae was a dominant strain causing streptococcicosis in the tested area due to occurrence of 21 strains as L. garvieae out of all the isolates, 9 atrains as Streptococcus sp. and 5 strains as Enterococcus sp.

• Korean journal of food and cookery science
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• v.11 no.3
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• pp.261-266
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• 1995

The survival and growth of Staphylococcus aureus and Listeria monocytogenes in fish homogenates (flounder, shrimp and oyster homogenate) and tryptic soy broth (TSB) were tested during storage at simulated ambient (35$^{\circ}C$), refrigerated (5$^{\circ}C$) and frozen (-20$^{\circ}C$) temperature. A similar growth pattern of S. aureus at 35$^{\circ}C$ was observed in fish homogenates and TSB. Survival of S. aureus decreased at refrigerated or frozen temperature and that was greater at -20$^{\circ}C$ (0.3-1.2 log reduction/6 weeks) than at 5$^{\circ}C$ (1-1.6 log reduction/3 weeks). Viable cells of L. monocytogenes increased rapidly at 35$^{\circ}C$ in flounder homogenate, shrimp homogenate and TSB but after a prolonged lag period in oyster homogenate. During 3 weeks of storage at 5$^{\circ}C$, the levels of L. monocytogenes increased 3.8-5.0 log cycles in flounder homogenate, shrimp homogenate and TSB whereas levels increased 2.2 log cycles in oyster homogenate. Viable cells of L. monocytogenes during 6 weeks of frozen storage decreased 1.5-1.8 log cycles in flounder homogenate, shrimp homogenate and TSB while decreased 2.8 log cycles in oyster homogenate.

• KSBB Journal
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• v.20 no.6
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• pp.438-442
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• 2005

Batch experiments were performed to investigate the effects of volumetric mixing ratio(v/v) of two substrates, food wastes(FW) and waste activated sludge(WAS). In batch experiments, optimum mixing ratio for hydrogen production was found at $10{\sim}20$ v/v % addition of WAS. CSTR(Continuous Stirred tank reactor) was operated to investigate the hydrogen productivity and the microbial community under various HRTs and volumetric mixing ratio(v/v) of two substrates. The maximum yield of specific hydrogen production, 140 mL/g VSS, was found at HRT of 2 day and the volumetric mixing ratio of 20:80(WAS:FW). The spatial distribution of hydrogen producing bacteria was observed in anaerobic fermentative reactor using fluorescent in situ hybridization(FISH) method.

• The Korean Journal of Food And Nutrition
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• v.21 no.2
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• pp.165-175
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• 2008

Pacific saury, Cololabis saira kwamaegi, is a traditional local food of the Eastern sea area centering around Pohang. It is well-recognized as being both tasty and nutritious. Nevertheless, bacterial contamination, excessive dryness, and compositional changes have made it edible only during the winter months. Therefore, to improve its storage, this study examined the effects of storage material, type, temperature, and duration on compositional changes in kwamaegi. The studied samples were kwamaegis that had been dried naturally for 15 days. The storage materials included an A-film, a self-developed multi-film made of polyethylene, polyamide, EVOH, and polyethylene; as well as a B-film made of polyethylene, nylon, polyethylene, nylon and polyethylene. The B films were used after pressing and laminating. The storage types included one whole fish(1G), or 2 divided fish(2G), to increase eating convenience. The 2G type was the muscle portion divided vertically after discarding the jowl, skin, and internal organs. The storage temperatures were $0^{\circ}C$, $-15^{\circ}C$, and $-30^{\circ}C$, and the storage durations were 2, 4, and 6 months. Pathogenic bacteria and rheology were measured to observe general compositional changes. The whole kwamaegi showed a total cell number of $1,565{\pm}112$ CFU/100 g flesh, while the divided Kwamaegi showed significantly greater bacterial numbers at $2,031{\pm}145$ CFU/100 g flesh. Psychrophils and halophils increased significantly while coliform were not found; the number of mesophils also increased, but not significantly. There were no significant cell number variations between the A-film and B-film. At $0^{\circ}C$, both the A-and B-films resulted in cell numbers of $115{\sim}212$ CFU/100 g flesh, revealing just $7.3{\sim}10.4%$ of the initial storage levels. Overall, there were no significant differences between the storage materials. Generally, as the storage temperature and duration increased, the moisture content of the kwamaegi decreased. Also, as storage duration and temperature increased, crude protein and crude lipid contents increased; in addition, they increased proportionally as the moisture content of the fish decreased. There were no significant differences in crude ash content with respect to the storage materials, storage temperatures, or storage durations. Finally, there were no significant differences between the kwamaegi samples naturally dried for 15 days and those stored in the B-film vacuum storage for 6 months for strength, hardness, cohesiveness, springiness, gumminess, and water activity.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.3
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• pp.240-248
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• 2006

In this study, a retrofitting BNR process that was modified for the economical applicability was proposed and evaluated in the pilot plant($50m^3/d$). At the same time the bacterial community structure was investigated in the pilot plant by using FISH(fluorescent in situ hybridization) method. Economically 16% of the initial construction cost for the proposed process(introduction of a biological nutrient removal process of $60,000m^3/d$ scale basis) was reduced due to the absence of a bioreactor. Water treatment efficiencies and maintenance facilities of the modified process were satisfied with the strengthened discharge permits in Korea throughout a long term pilot plant operating including a winter season. Bacterial populations in the pilot plant and in the control plant(A2/O process, B SIP(Sewage Treatment Plant)) were remained uniformly during the test period, but bacterial structure in the bioreactor was changed drastically. Proportions of ${\beta}$-proteobacteria group including soil bacteria which play a important role in wastewater treatment increased $25{\sim}607%$ in population.

• Journal of fish pathology
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• v.13 no.2
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• pp.111-119
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• 2000

One hundred and twenty three strains of bacterial flora collected from Kunsan bay and examined for drug resistance to 9 antibiotics. The isolated and examined bacteria were Vibrio spp.(44 strains), Pseudomonas spp.(42 strains), Aeromonas spp.(26 strains), Moraxella spp.(9 strains), Enterobacteria spp.(6 strains), Bordetella spp.(3 strains), Alkaligenesis spp.(3 strains), Staphylococcus spp.(3 strains), and Flavobacterium spp.(2 strains). The drugs used were Ampicillin(AM), Penicillin-G(PM), Rifampicin(RF), Streptomycin(SM), Oxolinic acid (OA), Nalidixic acid(NA), Oxytetracycline(OT), Amikacin(AK), and Enorfloxacin(EF). Forty two strains were found to be sensitive to all drugs. The remaining strains showed resistance to various combinations of drugs. Among the resistant strains were mostly restricted to AM(54 strains/43.9%), PM(47 strains/38.2%), RF(35 strains/28.4%), SM(9 strains), OA(5 strains/ 4.06%), and NA(1 strains/0.8%), in combination at high degree showing 15 different drug resistant patterns. The most frequently showed resistant patterns were AM-PM-RF(16 strains/13.4%), AM-PM(8 strains/6.5%), and PM-RF(7 strains/5.6%). These results suggested that Kunsan bay were contaminated with various strains of highly resistant strains to drugs(AM, PM and RF). These results suggest that high levels of various antibiotics have already been introduced to Kunsan bay. Furthermore it seems that chemotherapy of fish disease has become extremely difficult because of the acquirement of multi-drug resistance to wide range of antibiotics.

• Journal of fish pathology
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• v.34 no.1
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• pp.39-46
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• 2021

Tetracycline (TC) is one of the antibiotics used for treatment of bacterial infection in Korea. Inadequate usage and abuse cause the resistance to antibiotics, like Tetracycline, Erythromycin, and Fluoroquinolone. It can also affect severe economic loss in aquaculture field in Korea. We isolated 101 bacterial samples from diseased fish at aquaculture sites in Gyeonggi-do during 2015~2018. Minimum inhibitory concentration (MIC) method has been used to determine distribution and to identify bacterial isolates resistant to antibiotics including Oxytetracycline (OTC), Ampicillin (AMP), Clindamycin (CLI), Enrofloxacin (ENRO), Gentamycin (GEN). TC resistant isolates were confirmed antibiotic resistant genes by conventional PCR. Bacterial isolates were identified as Aeromonas spp. (43.5%), Pseudomonas spp. (4.0%) and Vibrio spp. (5.0%). It was confirmed that multi-resistant isolates (77.2%) were predominant over single-resistant one (22.8%). TC resistant genes like tet(A), tet(D), tet(E), tet(G), tet(M), and tet(S) were detected and tet(A) was the most prevalent. Aeromonas spp. is a dominant strain in bacterial infections in fishes of aquaculture sites, and further investigation on various antibiotic resistance genes will be needed for clear understanding of aquaculture sites in Gyeonggi-do.