• 한국수산과학회지
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• 제41권3호
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• pp.188-192
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• 2008

Methyl gallate isolated from bark of the tree Rhus verniciflua Stokes has significant antimicrobial activity against the fish pathogenic bacteria Edwardsiella tarda and Vibrio anguillarum. To evaluate the antimicrobial activity of gallate derivatives, eight alkyl gallates were tested. Ethyl gallate and propyl gallate had the highest activities, with MICs of $15.6-31.3{\mu}g/mL$ against E. tarda. For V. anguillarum, propyl gallate and butyl gallate were highly effective, with MICs of $7.81-31.3{\mu}g/mL$. When used in combination with antibiotics, methyl gallate exhibited synergistic effects with oxytetracycline against E. tarda and with norfloxacin against V. anguillarum. These results suggest that short-chain alkyl gallates can be used as alternatives to antibiotics against the fish pathogenic bacteria.

• Fisheries and Aquatic Sciences
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• 제1권2호
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• pp.209-215
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• 1998

Trypsin-like enzyme was purified from shrimp hepatopancreas through Q-Sepharose ionic exchange, benzamidine Sepharose-6B affinity, and Superdex 75 gel chromatography. Purity of trypsin-like enzyme was increased 69-fold with $44\%$ yield. The enzyme consisted of a single polypeptide chain with a molecular weight (M.W.) of 32 kDa judged by sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE). The enzyme was completely inactivated by serine enzyme inhibitors such as soybean trypsin inhibitor (SBTI), tosyl-L­lysine chloromethyl ketone (TLCK), and leupeptin. However, the enzyme was not affected by tosyl-L-phenylalanine chloromethyl ketone (TPCK) which is a chymotrypsin specific inhibitor. The enzyme had no activity against benzoyl-tyrosine ethyl ester (BTEE) which is a chymotrypsin specific substrate. The enzyme showed high activity on the carboxyl terminal of Phe, Tyr. Glu, Arg, and Asp. However. no activity was detected against the carboxyl terminal of Pro, Trp, Cys, Gly, Val, and Ala.

• 한국물환경학회지
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• 제24권5호
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• pp.592-597
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• 2008

Current water quality standard (WQS) in Korea is based on the protection of human health, not considering the protection of aquatic organisms. Most of chemicals can be toxic to ecological biota as well as human. Health of aquatic biota is closely related to the human health via food chain, therefore ecological risk based-WQS needs to be developed to protect the aquatic ecosystem. In this study, we selected the 31 chemicals in the Project entitled 'Development of integrated methodology for evaluation of water environment'. The methodology for calculating water quality criteria was derived from the Australian and New Zealand processes for deriving guideline trigger value for aquatic ecosystem. The available ecotoxicity data were collected from US EPA's ECOTOXicology Database (ECOTOX), TOX-2000 Database, European Chemicals Bureau (ECB)'s International Uniform Chemical Information Database (IUCLID) and Environmental Protection Agency (US EPA)'s report 'Ambient Water Quality Criteria (AWQC)'. The aquatic toxicity data for the Korean species were selected for risk assessment to reflect the Korean water environment. The monitoring values were calculated from the water quality monitoring data four main Korean rivers. We suggested the order of priorities of chemicals based on ecological risk assessment. We expect that these results can be useful information for establishing the WQS for the protection of aquatic ecosystem.

• 한국수산과학회지
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• 제55권6호
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• pp.844-849
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• 2022

The pathogenic Vibrio genus denotes halophilic bacteria that are distributed in aquatic environments, including both sea and freshwater. V. cholerae, V. vulnificus, and V. parahaemolyticus are the main species that can be potent human pathogens and the leading cause of septicemia, wound infections, and seafood borne gastroenteritis. The aim of this study was to investigate the presence of pathogenic Vibrios in seawater. We obtained a total of 80 seawater samples from the Geum River estuary area in the west coast of Korea from April to December 2021. Pathogenic Vibrios was determined using a combination of the most probable number-polymerase chain reaction (MPN-PCR) methods. The detection levels of V. cholerae, V. parahaemolyticus, and V. vulnificus in the seawater samples were 7.5%, 68.8%, and 30.0%, respectively. The quantitative results were as follows: 3.6-3.6 MPN/100 mL in V. cholerae, 3.6-3,400 MPN/100 mL in V. parahaemolyticus, and 3.6-4,300 MPN/100 mL in V. vulnificus. Overall, these results provide novel insight into the necessity for seawater sanitation in the Geum River estuary area, and could help reduce the risk of seafood-borne outbreaks caused by pathogenic Vibrios.

• 한국수산과학회지
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• 제22권3호
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• pp.115-120
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• 1989

Physicochemical changes were investigated during repeated freezing and thawing processes using fish meat paste of alaska pollack (Theragra chalcogramma). During repeated thawing process, the solubility of myofibrillar protein, $Ca^{++}-ATPase$ activity, water holding capacity (WHC), electrophoretic patterns and rheological properties were evaluated at various thawing temperatures. Solubility of myofibrillar protein and $Ca^{++}-ATPase$ activity were decreased with increasing thawing temperatures. Thawing temperatures and the frequency of freezing and thawing processes did not affect WHC significantly. Upon repeated freezing and thawing cycles, electrophoretic patterns showed that only the amount of myosin heavy chain was decreased, whereas the amount of actin remained constant. Young's modulus for viscoelasticity of fish meat pastes increased with increasing thawing temperatures and the value showed maximum at third cycle and decreased thereafter.

• 한국수산과학회지
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• 제29권6호
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• pp.797-804
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• 1996

Two trypsins were purified from shrimp hepatopancreas through ammonium sulfate fractionation, Q-Sepharose ionic exchange, benzamidine Sepharose-6B affinity, and Sephacryl S-300 gel chromatography. Both enzymes had a single polypeptide chain with a molecular weight (M.W.) of 32 kDa by sodium dodecylsulfate polyacrylamide gel electrophoresis (SOS-PAGE), although trypsin A and B were estimated to be a molecular weight of 27.2 and 22.8 kDa, respectively, using Sephacryl S-300 gel filtration. Both trypsins had similar amino acid compositions and rich in glycine, valine, alanine, aspartic acid, and glutamic acid, but low in methionine and basic amino acids. Both enzymes were completely inactivated by soybean trypsin inhibitor (SBTI), phenylmethylsulfonyl fluoride (PMSF), tosyl-L-lysine chloromethyl ketone (TLCK), benzamidine, leupeptin, however, not affected by tosyl-L-phenylalanine chloromethyl ketone (TPCK) and pepstatin.

• 한국수산과학회지
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• 제29권3호
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• pp.296-308
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• 1996

혈합육어 (멸치와 전어)와 백색육어 (농어와 도다리)의 육과 내장에서 추출한 조효소에 대하여 천연기질 및 합성 기질에 대한 효소 활성과 disc-PAG 전기영동에서 분리된 효소 단백질의 분포를 선택적 합성기질을 써서 비교 검토하였다. 육에는 SH-proteinase인 cathepsin L, B, 및 H 유사 효소가 분포하는 것을 확인 할 수 있었으며, 이 밖에도 cathepsin G 및 D도 다소 분포하는 것으로 추정되었다. 그리고 내장에는 강한 활성의 chymotrypsin 및 trypsin 유사 효소가 주로 분포하고 있음이 확인되었다. 육과 내장에서 추출한 조효소들은 공통적으로 멸치, 전어, 도다리 그리고 농어의 순으로 활성이 높은 것을 알 수 있었으며, 전체적으로 혈합육어에 분포되어 있는 효소가 백색육어류에 분포되어 있는 효소에 비하여 약 100배정도 높았다. 육과 내장의 조효소를 방어의 근원섬유단백질에 작용시킨 결과, 육 중의 조효소는 myosin heavy chain의 분해가 두드러졌으며, 특히 멸치의 효소가 근원섬유 단백질의 구성 subunit 모두에 대하여 강한 분해능을 보였다. 내장 조효소의 경우는 반응 초기에 myosin heavy chain과 actin을 현저하게 분해시켰으며, 혈합육어인 멸치와 전어 조효소의 분해능이 백색육어인 농어와 도다리의 조효소보다 강한 것을 확인 할 수 있었다. 육의 조효소는 어종에 따라 서로 다른 분해 양상을 보였으며, 내장 조효소는 혈합육어와 백색육어의 효소 활성뿐만 아니라 효소의 분포상으로도 많은 차이가 있었다.

• Advances in environmental research
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• 제1권1호
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• pp.15-35
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• 2012

Mercury (Hg) is a global environmental pollutant that has been the cause of many public concerns. One particular concern about Hg in aquatic systems is its trophic transfer and biomagnification in food chains. For example, the Hg concentration increases with the increase of food chain level. Fish at the top of food chain can accumulate high concentrations of Hg (especially the toxic form, methylmercury, MeHg), which is then transferred to humans through seafood consumption. Various biological and physiochemical conditions can significantly affect the bioaccumulation of Hg-including both its inorganic (Hg(II)) and organic (MeHg) forms-in fish. There have been numerous measurements of Hg concentrations in marine and freshwater fish worldwide. Many of these studies have attempted to identify the processes leading to variations of Hg concentrations in fish species from different habitats. The development of a biokinetic model over the past decade has helped improve our understanding of the mechanisms underlying the bioaccumulation processes of Hg in aquatic animals. In this review, I will discuss how the biokinetic modeling approach can be used to reveal the interesting biodynamics of Hg in fish, such as the trophic transfer and exposure route of Hg(II) and MeHg, as well as growth enrichment (the increases in Hg concentration with fish size) and biomass dilution (the decreases in Hg concentration with increasing phytoplankton biomass). I will also discuss the relevance of studying the subcellular fates of Hg to predict the Hg bioaccessibility and detoxification in fish. Future challenges will be to understand the inter- and intra-species differences in Hg accumulation and the management/mitigation of Hg pollution in both marine and freshwater fish based on our knowledge of Hg biodynamics.

• 한국수산과학회지
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• 제41권6호
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• pp.427-434
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• 2008

Processing of collagen from yellowfin tuna (Thunnus albacares) abdominal skins was optimized by response surface methodology and central composite design. The values of independent variables at optimal conditions were NaOH concentration: 0.5 N, NaOH treatment time: 36.2 hr, pepsin concentration: 1:4.9 ratio (0.245%, w/v), and digestion time: 48.1 hr, respectively. The collagen content estimated under optimal conditions was 33.1%, and the actual experimental collagen content was 32.3%. Physicochemical properties of collagen from yellowfin tuna abdominal skin were investigated by amino acids analysis, SDS-PAGE, FT-IR, viscosity and denaturation temperature. Amino acids content of the collagen was 21.0%. SDS-PAGE pattern of the collagen showed two different $\alpha$-chain (${\alpha}_1$- and ${\alpha}_2$- chain), $\beta$-component and $\gamma$-component. The spectrum of FT-IR of the collagen showed wavenumber at 3,434, 1,650, 1,542 and $1,235\;cm^{-1}$ representing the regions of amide A, I, II and III, respectively. Relative viscosity of the collagen decreased continuously on heating up to $32^{\circ}C$, and the rate of decrease was retarded in the temperature range of $35-50^{\circ}C$. Denaturation temperature (Td) of the collagen solution (0.06%, w/v) was $31^{\circ}C$ and was lower than calf skin collagen ($35^{\circ}C$).

• Fisheries and Aquatic Sciences
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• 제24권8호
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• pp.277-283
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• 2021

Kudoa septempunctata has been reported as a new parasite in aquacultured olive flounder Paralichthys olivaceus, and also as a causative agent of food poisoning in humans. This paper investigated the infection of K. septempunctata in 216 sashimi and 20 sushi made of olive flounders in Busan, Korea. Among 236 samples, K. septempunctata was detected in eleven sashimi with 6-7 polar capsules by the microscopy. Among eleven sashimi, five sashimi were positive in Polymerase Chain Reaction (PCR) assay with the targets of 18S rDNA and 28S rDNA. The genotype of all the five PCR results is identified as the genotype ST3 which is common in Korea. K. septempunctata was found in olive flounders sashimi from Samcheonpo and Wando outside of Jeju Island. These findings would contribute to establish the standard of K. septempunctata for preventing food-borne outbreaks in advance and providing further preventive management for the seafood safety.