• Fisheries and Aquatic Sciences
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• v.17 no.2
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• pp.215-222
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• 2014

To explore marine microorganisms with medical potential, we isolated and identified marine bacteria from floats, marine algae, animals, and sponges collected from Jeju Island, Korea. We isolated and identified 21 different strains from the marine samples by 16S rRNA analysis, cultured them in marine broth, and extracted them with ethyl acetate (EtOAc) to collect secondary metabolite fractions. Next, we evaluated their anti-oxidative and anti-inflammatory effects. Among the 21 strains, the secondary metabolite fraction of Bacillus badius had both strong antioxidant and anti-inflammatory activity, and thus was selected for further experiments. An antioxidant compound detected from the secondary metabolite fraction of B. badius was purified by preparative centrifugal partition chromatography (n-hexane:EtOAc:methanol:water, 4:6:4:6, v/v), and identified as diolmycin A2. Additionally, diolmycin A2 strongly inhibited nitric oxide production. Thus, we successfully identified a significant bioactive compound from B. badius among the bacterial strains collected from Jeju Island.

• Korean Journal of Crystallography
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• v.16 no.2
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• pp.66-74
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• 2005

Marine natural products with various bioactivities are featured with similar structure to the common secondary metabolites and generally modified by halogenides, such as chloride, bromide, and iodide ions. Vanadium haloperoxidase is a key enzyme for the production of marine natural products and a metalloenzyme which requires a cofactor of vanadate. This review will cover isolation of vanadium haloperoxidase and the protein structures, as well as reaction mechanism of the metalloenzyme. Finally, reactivity of vanadium haloperoxidase and the biosynthesis of the secondary metabolites of indole, terpenoids, and acetogenins will be described.

• Journal of Microbiology and Biotechnology
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• v.32 no.5
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• pp.541-550
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• 2022

Filamentous marine fungi have proven to be a plentiful source of new natural products. Chaetomium, a widely distributed fungal genus in the marine environment, has gained much interest within the scientific community. In the last 20 years, many potential secondary metabolites have been detected from marine-derived Chaetomium. In this review, we attempt to provide a comprehensive summary of the natural products produced by marine-derived Chaetomium species. A total of 122 secondary metabolites that were described from 2001 to 2021 are covered. The structural diversity of the compounds, along with details of the sources and relevant biological properties are also provided, while the relationships between structures and their bioactivities are discussed. It is our expectation that this review will be of benefit to drug development and innovation.

• Journal of Microbiology and Biotechnology
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• v.32 no.11
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• pp.1416-1426
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• 2022

The need to discover new types of antimicrobial agents has grown since the emergence of antibiotic-resistant pathogens that threaten human health. The world's oceans, comprising complex niches of biodiversity, are a promising environment from which to extract new antibiotics-like compounds. In this study, we newly isolated Pseudomonas sp. NIBR-H-19 from the gut of the sea roach Ligia exotica and present both phenotypes and genomic information consisting of 6,184,379 bp in a single chromosome possessing a total of 5,644 protein-coding genes. Genomic analysis of the isolated species revealed that numerous genes involved in antimicrobial secondary metabolites are predicted throughout the whole genome. Moreover, our analysis showed that among twenty-five pathogenic bacteria, the growth of three pathogens, including Staphylococcus aureus, Streptococcus hominis and Rhodococcus equi, was significantly inhibited by the culture of Pseudomonas sp. NIBR-H-19. The characterization of marine microorganisms with biochemical assays and genomics tools will help uncover the biosynthesis and action mechanism of antimicrobial metabolites for development as antagonistic probiotics against fish pathogens in an aquatic culture system.

• Journal of Microbiology and Biotechnology
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• v.31 no.4
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• pp.601-609
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• 2021

Erythrobacter species are extensively studied marine bacteria that produce various carotenoids. Due to their photoheterotrophic ability, it has been suggested that they play a crucial role in marine ecosystems. It is essential to identify the genome sequence and the genes of the species to predict their role in the marine ecosystem. In this study, we report the complete genome sequence of the marine bacterium Erythrobacter sp. 3-20A1M. The genome size was 3.1 Mbp and its GC content was 64.8%. In total, 2998 genetic features were annotated, of which 2882 were annotated as functional coding genes. Using the genetic information of Erythrobacter sp. 3-20A1M, we performed pan-genome analysis with other Erythrobacter species. This revealed highly conserved secondary metabolite biosynthesis-related COG functions across Erythrobacter species. Through subsequent secondary metabolite biosynthetic gene cluster prediction and KEGG analysis, the carotenoid biosynthetic pathway was proven conserved in all Erythrobacter species, except for the spheroidene and spirilloxanthin pathways, which are only found in photosynthetic Erythrobacter species. The presence of virulence genes, especially the plant-algae cell wall degrading genes, revealed that Erythrobacter sp. 3-20A1M is a potential marine plant-algae scavenger.

• Journal of Microbiology and Biotechnology
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• v.11 no.4
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• pp.663-667
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• 2001

A new secondary metabolite was isolated from the culture broth and mycelium of Streptomyces sp. collected from marine sediment. The structure of this compound was determined to be N-formylantimycic acid methyl ester, an acyclic derivative of antimycin, on the basis of combined chemical and spectral methods. The structure-activity relationship of antimycins is discussed.

• Archives of Pharmacal Research
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• v.29 no.1
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• pp.59-63
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• 2006

Secalonic acid D(SAD) was isolated as the major secondary metabolite of the marine lichen-derived fungus Gliocladium sp. T31. Its structure was established on the basic of physicochemical and spectroscopic data. This is the first report on the isolation of SAD from this fungus, as well as its inhibitory effect on K562 cell cycle and its cytotoxicity against several tumor cell lines in vitro.

• YAKHAK HOEJI
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• v.41 no.3
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• pp.345-351
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• 1997

The purpose of this investigation was to determine the inhibition of $Na^+,\;K^+$-ATPase, cyclicAMP phophodiesterase and platelet activation by secondary metabolites isolated from mar ine organisms. The secondary metabolites were isolated and identified as six diterpenoids(1 : astrogorgin, 2 : ophirin, 3 : calicophirin B, 4, 5 and 6 : cladiellin) from the dichloromethane extract of Muricellajsp., four ceramides(1,2,3, and 4) from Acabaria undulata and three antharaquinones(1,2 : crysophanol, and 3 : physcion) from Urechis unicintus. The results demonstrated that diterpenoids(2,3, and 4) showed the inhibition of cyclicAMP phosphodiesterase, and ceramides(1,3, and 4) showed the inhibition of cyclicAMP phosphodiesterase and thrombin(0.1 units/ml)-induced aggregation of washed rabbit platelet, and anthrapuinones((1,2, and 3) showed the inhibition of $Na^+,\;K^+$-ATPase. Among the anthraquionones, 1,2-dimethoxy-3-methyl-8-hydroxy-anthraquinone(1) showed the inhibition of collagen(1.0 ${\mu}g$/ml)-induced aggregation in a concenration-dependent manner with IC50 value of 42.8 ${\mu}g$M.

• Natural Product Sciences
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• v.21 no.4
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• pp.273-277
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• 2015

Comprehensive chemical analysis of extracts and fractions of marine actinomycete strains led to the discovery of a new minor secondary metabolite, salternamide E (1), from a saltern-derived halophilic Streptomyces strain. The planar structure of salternamide E (1) was elucidated by a combinational analysis of spectroscopic data including NMR, MS, UV, and IR. The absolute configuration of salternamide E (1) was determined by circular dichroism spectroscopic analysis. Salternamide E displayed weak cytotoxicity against various human carcinoma cell lines.