• Journal of Nutrition and Health
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• v.31 no.8
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• pp.1217-1225
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• 1998

This study was conducted to investigate the effects of shellfish on lipid metabolism in rats fed high fat supplements. Male sprague-dawley rats weighting approximately 165g were fed a basal diet, a high fat diet, or a high fat diet plus shellfish for 4 weeks. The shellfishes on the were oyster, hard-shelled mussel, little neck clam, and march clam. Alfter 4 weeks high fat diet, supplementation of 20% lard significantly increased plasma. GOT, GPT, ${\gamma}$-GTP , and liver triglyceride (TG). Plasma GOT, GPT, ${\gamma}$-GTP , triglyceride, and total cholestrerol levels were significantly lower in shellfish groups than in basal and high-fat groups regardless of high-fat supplementation (p<0.05). The total lipid and cholesterol content in liver showed similar results(p<0.05). There were no differences in glucose, HDL-cholesterol in plasma and total cholesterol and total lipid in liver between basal and high-fat supplemented diets. Liong chain fatty acids, specific components of shellfishes group, were exclusively higher than in basal and high-fat diets, and were most well-reflected in liver and plasma. From the above results, the hypolipidemic effects of shellfish were detected in the process of inducing hyperlipidemia by high-fat supplement.

• Journal of Nutrition and Health
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• v.33 no.4
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• pp.386-394
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• 2000

This study was conducted to investigate the effects of shellfish hydrolysate on lipid metabolism in rats fed high fat diet. Male Sprague-Dawley rate weighting approximately 110g were fed basal control diet, high fat diet and high fat diet plus 4 different shellfish hydrolyates for 4 weeks. The shellfish hydrolysates from the different sources, were oyster, hard-shelled mussel, little neck clam and march clam. After 4 weeks, serum GOT, GPT, ${\gamma}$-GTP, triglyceride and total cholesterol was significantly decreased in shellfish hydrolysates supplementation with high fat diet compared to basal control and high-fat group(p<0.05). The total lipid and cholesterol content in liver showed significant decrease(p, 0.05). There were no different in serum GPT, HDL-cholesterol, liver total cholesterol and lipid of rats between basal control diet and high-fat diet. The unsaturated fatty acids, specific components of shellfishes were a little components in shellfish hydrolysate as they were a low and not different among the groups and were most well reflected in liver and plasma. Considering digestive and absorptive process of in human body, it was assumed that the hypolipidemic effect of shellfish was not under the influence of unsaturated fatty acids but the other components, peptides, taurine and betaine and so on was detected in the process of hyperlipidemia induced by high-fat diet.

• Journal of the Korean Chemical Society
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• v.41 no.2
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• pp.105-112
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• 1997

The smelly nitro compounds were extracted from dried fishes by simultanous distillation and extraction, then were analyzed by GC-MS. Carbon number and order of an amine could be predicted by using retention time and equivalent chain length. Anchovy, codfish, imitation crab meat, cuttle fish, file fish, pollack, shrimp, octopus, harvest fish, and hard-shelled mussel were used for this investigation. Various smelly nitro compounds such as methylamine, acetamide, thiazole, 2-hydroxy isopropylamine, N-methyl pyrroline, piperidine, cyclohexylamine were identified, however, dimethylamine, trimethylamine, diethylamine were not detected. Principal components analysis was applied to GC-MS profiles for pattern recognition of smelly nitro compounds in dried fishes. Multivariate aspects using principal components analysis were very useful for pattern recognition of smelly components, category similarity.

• Journal of Aquaculture
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• v.17 no.2
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• pp.103-108
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• 2004

Effects of temperature and salinity were investigated on physiological responses of Mytilus coruscus seedlings. Temperature tolerance and survival of M. coruscus, were examined at temperature 20, 25, 28, 30 and 35$^{\circ}C$ for 9 das. Survival of M. coruscus was 90% at temperature 2$0^{\circ}C$ and $25^{\circ}C$. LT$_{50}$ (lethal temperature) of 9 days was at 27.1$^{\circ}C$. The respiration and filtration rates of M. coruscus were increased with temperature up to $25^{\circ}C$, and decreased with temperature ranged from $25^{\circ}C$ to 3$0^{\circ}C$. LS$_{50}$ (lethal salinity, psu) of 9 days at 1$0^{\circ}C$, 15$^{\circ}C$ and $25^{\circ}C$ were 17.01 psu, 19.95 psu and 21.79 psu respectively. Salinity affected survival of M. coruscus with higher temperature. However the respiration and filtration rates were reduced with lower salinity.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.6
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• pp.927-937
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• 2021

This study was performed to screen the antimicrobial activities of the extract from the Pacific oyster Crassostrea gigas against skin pathogens and to purify the relevant antibacterial peptide. The acidified extract showed potent antibacterial activities against gram-positive and gram-negative bacteria but showed no activity against Candida albicans and no significant cell toxicity. Among acne-causing pathogens, the acidified extract showed potent antibacterial activity only against Staphylococcus aureus, and its antibacterial activity was completely abolished by treatment with trypsin or chymotrypsin, and was inhibited by salt treatment. The acidified extract showed strong DNA-binding ability but did not show bacterial membrane permeabilizing ability. Based on antimicrobial activity screening and cytotoxic effects, a novel antibacterial peptide was purified from the acidified gill extract using solid-phase extraction, cation-exchange, and reversed-phase HPLC. The resulting peptide had a molecular weight of 4800.8 Da and showed partial sequence homology with the carbonic anhydrase 4 (CA4) protein in the hard-shelled mussel. Overall, we purified a novel antibacterial peptide, named cgCAFLP, which is related to carbonic anhydrase 4 (CA4) protein, against skin pathogens. Our results suggest that the Pacific oyster extract could be used as an additive to control some acne-related skin pathogens (S. aureus).

• Korean Journal of Food Science and Technology
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• v.34 no.6
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• pp.1130-1133
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• 2002

Domoic acid, and amnesic shellfish poison, is a neurotoxin frequently found in shellfishes. Guidance level for the consumable shellfish has been established as $20\;{\mu}g$ domoic acid/g by Health and Welfare Canada and U.S. FDA. Domoic acid is produced by pennate diatom, a Nitzschia pungens f. multiseries ingested by the shellfish. Content of domoic acid in shellfish samples collected along the Korean shoreline from May to December of 1999 was analyzed. The collection included 1 Gastropoda (Murex shell) and 11 Bivalvias (oyster, little neck clam, orient hard clam, venus clam, surf clam, ark shell, hard-shelled mussel, pen shell, jack-knife clam, pink butterfly shell, and granulated ark shell). Samples were homogenized, extracted with 50% methanol, filtered, and analyzed by reversed-phase liquid chromatography at 242 nm with mobile phase consisting of 10% acetonitrile and 0.1% trifluoroacetic acid. Recovery of the HPLC analysis was 95.80% (${\pm}1.09$). All tested samples showed no domoic acid at the detection limit of 50 ng/g.

• Journal of Life Science
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• v.26 no.11
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• pp.1259-1268
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• 2016

In this study, we investigated antimicrobial peptide from the acidified muscle extract of Mytilus coruscus, which mostly inhabits China, Japan, and Korea, to develop a natural product-derived antibiotics substitution in terms of its abuse and restriction. Antimicrobial peptide was purified by $C_{18}$ reversed-phase high-performance liquid chromatography and was detected as having a molecular mass of 6,701 Da by MALDI-TOF/MS. The N-terminal amino acid sequence of the purified peak was obtained from edman degradation, and 20 identified residues shown 100% identity with the N-terminus region of sperm-specific protein and protamine-like PL-II/PL-IV precursor of Mytilus californianus. We also identified 60 open-reading frame (ORF) encoding amino acids with 183 bp of purified peptide based on the obtained amino acid residues. The amino acid sequence of ORF showed 100% and the nucleotide sequence revealed 97.2% identity with the protamine-like PL-II/PL-IV precursor of Mytilus californianus. Synthesized antimicrobial peptide showed antimicrobial activity against gram-positive bacteria, including Bacillus cereus (minimal effective concentration [MEC], $20.8{\mu}g/ml$), Bacillus subtilis (MEC, $0.2{\mu}g/ml$), Streptococcus mutans (MEC, $0.2{\mu}g/ml$), gram-negative bacteria including Pseudomonas aeruginosa (MEC, $5.7{\mu}g/ml$), Escherichia coli (MEC, $2.6{\mu}g/ml$) and fungi, Candida albicans (MEC, $56.3{\mu}g/ml$). In addition, synthesized peptide showed stable activities under heat and salt conditions against gram-positive and gram-negative bacteria, but was inhibited by salt against only C. albicans. With these results, isolated peptide from M. coruscus could be an alternative agent to antibiotics for defending against pathogenic microorganisms, and helpful information to understand the innate immune system of marine invertebrates.

• Journal of Life Science
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• v.28 no.11
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• pp.1301-1315
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• 2018

We purified an antimicrobial peptide from the acidified hemocyte extract of Mytilus coruscus by $C_{18}$ reversed-phase high-performance liquid chromatography (RP-HPLC). The peptide was 4041.866 Da based on matrix-assisted laser desorption ionization time-of-flight mass spectrophotometer (MALDI-TOF/MS) and the 25 amino acids of the N-terminus sequence were identified. Comparison of this sequence of the purified peptide with the N-terminus sequences of other antimicrobial peptides revealed 100% identity with the mytilin B precursor of Mytilus coruscus. We also identified a 312 bp open-reading frame (ORF) encoding 103 amino acids based on the obtained amino acid residues. The nucleotide sequence of this ORF and the amino acid sequence also revealed 100% identity with the mytilin B precursor of Mytilus coruscus. We synthesized two antimicrobial peptides with an alanine residue in the C-terminus, and designated them mytilin B1 and B2. These two antimicrobial peptides showed antimicrobial activity against gram-positive bacteria, including Bacillus cereus and Streptococcus parauberis (minimal effective concentration, MECs $41.6-89.7{\mu}g/ml$), gram-negative bacteria, including Enterobacter cloacae, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Providencia stuartii, Pseudomonas aeruginosa, and Vibrio ichthyoenteri (MECs $7.4-39.5{\mu}g/ml$), and the fungus Candida albicans (MECs $26.0-31.8{\mu}g/ml$). This antimicrobial activity was stable under heat and salt conditions. Furthermore, the peptides did not exhibit significant hemolytic activity or cytotoxic effects. These results suggest that mytilin B could be applied as alternative antibiotic agent, and they add to the understanding of the innate immunity of hard-shelled mussels.

• Journal of Life Science
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• v.13 no.4
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• pp.390-399
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• 2003

Four species of the genus of Listeria were isolated from seawater and sea food in Kyungnam province, South Korea. These isolated strains were classified into Listeria sp. from different samples by appropriate cultivation conditions and biochemical tests including serological test. In a day enrichment cultivation, the following strains were found out of 100 samples: L. innocua (35%), L. ivanovii (4%), L. monocytogenes (4%), and L. welshimeri (1%). For seven days enrichment culture, L. innocua (38%), L. ivanoii (5%), L. monocytogenes (7%), and L. welshimeri (1%) were isolated. From these results, Listeria species were more efficiently isolated in seven day enrichment broth than in one day enrichment. However, these isolated Listeria species were less grown in the selective medium than in the enrichment medium. Isolation rates of Listeria species showed differency for each sample and Listeria species were more abundantly isolated in shrimps (80%) and crayfishes (80%) than little neck clams (50%), seawater (25%) and mussels (20%). From the results of serological classes for the seven L. monocytogenes, two strains were defined as type I and the other five strains as type IV.

• Journal of Life Science
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• v.27 no.11
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• pp.1276-1289
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• 2017

This study isolated and purified the antimicrobial peptide McSSP-31 from an acidified hemocyte extract of a Mytilus coruscus. The antimicrobial peptide was purified by using a $C_{18}$ reversed-phase high-performance liquid chromatography (HPLC). The peptide was determined to be 3330.549 Da by matrix assisted-laser desorption ionization time-of-flight mass spectrophotometer (MALDI-TOF/MS). The N-terminus of a 14 amino-acid sequence was identified as P-S-P-T-R-R-S-T-S-R-S-K-S-R by Edman degradation method. The acquired sequence showed a 93% similarity with the sperm-specific protein Phi-1, which is from M. californianus. The identified open-reading frame (ORF) of peptide was 306 bp encoding 101 amino acids, which was analyzed by rapid amplification of cDNA ends (RACE), cloning and sequencing analysis. We compared the full sequence with other known proteins that reveal the sperm-specific protein Phi-1 (93.5%) of M. californianus. Synthesized antimicrobial peptide (McSSP-31) showed antibacterial activity against gram-positive bacteria including B. subtilis, S. mutans, S. aureus and gram-negative bacteria including E. coli, K. pneumoniae, P. mirabilis, P. aeruginosa and fungi, C. albicans. Also, synthesized peptide showed strong antibacterial activity against antibiotic-resistant strains, including S. aureus. The cytotoxicity of the peptide was determined by using the HUVEC human cell line. The peptide did not exhibit any significant cytotoxic effects on the normal human cell line, and it had very low hemolytic activity with flounder hemoglobin. The results demonstrated that peptide purified from the hemocyte of a M. coruscus exhibits antibacterial activity against various bacteria and has the potential to be an alternative antibiotic agent.