• Journal of Microbiology and Biotechnology
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• v.27 no.6
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• pp.1078-1089
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• 2017

Biofilm formation of Staphylococcus aureus is one of its mechanisms of drug resistance. Anti-biofilm screening of 106 compounds from marine-derived fungi displayed that 12 compounds inhibited S. aureus biofilm formation by >50% at the concentration of $100{\mu}g/ml$, and only secalonic acid D (SAD) and B inhibited by >90% at $6.25{\mu}g/ml$ without inhibiting cell growth after 24-h incubation. Meanwhile, it was found that the double bond between C-1 and C-10 of citrinin derivatives and the C-C connection position of two chromone monomers may be important for their anti-biofilm activities. Moreover, SAD slightly facilitated biofilm eradication and influenced its architecture. Furthermore, SAD slowed the cell growth rate in the preceding 18-h incubation and differentially regulated transcriptional expression of several genes, such as agr, isaA, icaA, and icaD, associated with biofilm formation in planktonic and biofilm cells, which may be the reason for the anti-biofilm activity of SAD. Finally, SAD acted synergistically against S. aureus growth and biofilm formation with other antibiotics. These findings indicated that various natural products from marine-derived fungi, such as SAD, could be used as a potential biofilm inhibitor against S. aureus.

• Journal of Marine Bioscience and Biotechnology
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• v.12 no.1
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• pp.1-10
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• 2020

Asthma is a complex inflammatory disease of the lung characterized by variable airflow obstruction, airway hyperresponsiveness, airway inflammation, and reduction of respiratory function. Its prevalence and incidence are increasing because of the effect of various environmental and lifestyle risk factors. Steroid inhalation, long-acting agonists, and other synthetic drugs are used for the treatment of this disease. However, they have some side effects and show unsatisfied result and response after treatment. Therefore, many researchers have focused on the development of natural product-related treatment for asthma to suppress the side effects and unsatisfied results. Seaweeds contain various bioactive compounds with anti-inflammatory, antibacterial, and anti-oxidant activities. Thus, we investigated the asthma treatment-related literature using marine algae via the Google scholar search engine. Consequently, the literature is rarely investigated, but is increasing steadily. The literature was performed as a comparison study with an ovalbumin-induced group or drug-treated group, and investigated the antiasthma activity of algae ethanol extract. Although many researchers have studied marine algae-derived therapeutic agents for asthma, the amount of literature is rare compared with those of herbal medicine-derived therapeutic agents. Conclusively, we suggest that many researchers should investigate and develop algae-derived therapeutic agents for asthma treatment.

• Natural Product Sciences
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• v.6 no.3
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• pp.122-125
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• 2000

Allenic and epoxy carotenoid, fucoxanthin (1) was isolated from the marine bacillariophycean microalga Hantzschia marina and the structure was assigned on the basis of comprehensive spectroscopic analyses. Fucoxanthin was detected only from diatom among three families (green algae, diatom and blue-green algae) of the marine microalgae tested. Fucoxanthin showed free radical scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH) and peroxynitrite $(ONOO^-)$ with $IC_{50}$ values of $32\;{\mu}M\;and\;60\;{\mu}M$, respectively.

• 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.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.40 no.6
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• pp.343-349
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• 2007

This study examined the effective utilization of pearl processing by-products. Three extracts of hot-water extract (WE), hydro-cooked extract (HE), and two-step enzymatic hydrolysate (EH) were prepared from pearl oyster muscle, and their characteristics were examined. The moisture, crude protein, volatile basic nitrogen (VBN), and amino-N contents were 97.5-98.0%, 0.5-1.3%, 2.1-4.9 g/100 mL, and 35.0-74.5 g/100 mL, respectively. EH had the lowest VBN and highest amino-N contents. In addition, EH had the highest yields. In terms of its functional properties, EH inhibited angiotensin-I converting enzyme ($IC_{50}$, 1.39 mg/mL) more strongly than the other extracts ($IC_{50}$, 4.17-7.95 mg/mL). The free amino acid contents of WE, HE, and EH were 661, 470 and 1,150 mg/100 mL, respectively. Major amino acids were taurine and glutamic acid. Major inorganic ions were Na, Mg, and Ca. Contents of taste compounds, such as free amino acids, inorganic ions, and quaternary ammonium bases, differed significantly according to the extract methods. Based on the results of chemical experiments and sensory evaluation, the quality of EH was superior to the other extracts, and EH is suitable for use in natural flavoring materials.

• Journal of Life Science
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• v.33 no.7
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• pp.593-604
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• 2023

The ocean accounts for over 70% of the Earth's surface and is a space of largely unexplored unknowns and opportunities. Korea is a peninsula surrounded by the sea on three sides, emphasizing the importance of marine research. The ocean has an extremely complex environment with immense biological diversity. In terms of microbiology, the marine environment has varying factors like extreme temperature, pressure, solar radiation, salt concentration, and pH, providing ecologically unique habitats. Due to this variety, marine organisms have very different phylogenetic classifications compared with terrestrial organisms. Although various microorganisms inhabit the ocean, studies on the diversity, isolation, and cultivation of marine microorganisms and the secondary metabolites they produce are still insufficient. Research on bioactive substances from marine microorganisms, which were rarely studied until the 1990s, has accelerated in terms of natural products from marine Actinomycetes since the 2000s. Since then, industries for bioplastic and biofuel production, carbon dioxide capture, probiotics, and pharmaceutical discovery and development of antibacterial, anticancer, antioxidant, and anti-inflammatory drugs using bacteria, archaea, and algae have significantly grown. In this review, we introduce current research findings and the latest trends in life science and biotechnology using marine microorganisms. Through this article, we hope to create consumer awareness of the importance of basic and applied research in various natural product-related discovery fields other than conventional pharmaceutical drug discovery. The article aims to suggest pathways that may boost research on the optimization and application of future marine-derived materials.

• The Journal of the Korean Society for Microbiology
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• v.21 no.3
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• pp.345-353
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• 1986

Authors studies on the isolation of non-sucrose fermentation Vibrio species such as V. parahaemolyticus, V. vulnificus and V. damsela from sea water, shellfishes and various algae at Ulleung island in the east of Korea on summer in 1985. Authors carried out test for isolated strains to biochemical characteristics, halophilism, hemolysis and serological reaction. The results obtained were as follows: 1. Strains isolated from total specimens were 25 strains of V. parahaemolyticus, 2 strains of V. vulnificus and 1 strain of V. damsela, respectively. 2. Isolated frequency of Vibrio species from sea water and marine products was lower than on specimens in the southern sea of Korea from 1980 to 1985. 3. On hemolysis reaction on blood agar media using human and rabbit erythrocytes, 14 strains among 25 strains of V. parahaemolyticus isolated were positive, and V. vulnificus and V. damsela were positive, respectively. 4. The distributions of serotypes of V. parahaemolyticus isolated were from O1 group to O10 group, and from K 10 to K 69. The results of K serotypes were as follows ; serotype K 10 and K 33 were 2 strains, serotype K 59 and K 69 were 1 strain, respectively. And 2 strains of V. vulnificus isolated were not agglutinated by antiserum of V. vulnificus. Therefore, the probability is that 2 strains of V. vulnificus isolated were other serotypes distributed on sea weater and marine products of Ulleung island of Korea.

• Natural Product Sciences
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• v.11 no.1
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• pp.50-53
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• 2005

Bioassay-directed fractionation of the lipophilic extract of a marine sponge Sarcotragus sp. led to the isolation of a known trisoxazole containing macrolide, mycalolide B (1). Its structure was identified by NMR and MS analyses. This is the first report on the isolation of macrolide from a sponge of the genus Sarcotragus (Order: Dictyoceratida).

• Natural Product Sciences
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• v.11 no.3
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• pp.136-138
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• 2005

Bioassay-guided fractionation of an organic extract of the broth from the marine-derived fungus of the genus Aspergillus led to the isolation of the polyketides, (+)-epoxydon (1), (+)-epoxydon monoacetate (2), gentisyl alcohol (3), 3-chlorogentisyl alcohol (4), and methylhydroquinone (5). Compounds 1-5 showed a potent antibacterial activity against the methicillin-resistant and multidrug-resistant Staphylococcus aureus (MRSA and MDRSA) with MIC (minimum inhibitory concentration) values of 12.5, 12.5, 12.5, 50.0, and $6.2\;{\mu}g/mL$, respectively. Compounds 1-4 also exhibited a significant radical scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH) with $IC_{50}$ values of 6.0, 15.0, 7.0, and $1.0\;{\mu}M$, respectively.

• BMB Reports
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• v.33 no.4
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• pp.353-357
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• 2000

A new assay method of ${\alpha}-Oxidase$ (fatty acid : oxygen dioxygenase, 1-decarboxylating) was developed using a bioluminescence reaction system of marine luminous bacterium, Photobacterium phosphoreum. ${\alpha}$-Oxidase was isolated from a cucumber (Cucumis sativus). Pentadecanoic acid was used as a substrate, and the product, tetradecanal, was analyzed with a bacterial luciferase-coupled reaction. Initial light intensity was directly related to the concentration of tetradecanal in the range of 1 nM to 10 ${\mu}M$. Optimal pH and temperature were 7.5 and $25^{\circ}C$, respectively. Optimal pentadecanoic acid concentration in a standard assay of ${\alpha}$-oxidase was 0.1 mM. The Km value of pentedecanoic acid was $85{\mu}M$. This method is straightforward, rapid, convenient, and easy. Its needs no treatment or extraction of reaction mixture.