• Natural Product Sciences
• /
• v.26 no.2
• /
• pp.118-131
• /
• 2020

Mushrooms are known for their various attributes in the fields of nutrition and therapeutics. With exceptional taste, aroma, and nutritional value, they are considered 'functional food'-improving health and providing nutritional benefits to the body. Mushrooms have also been widely applied therapeutically as they possess diverse bioactive compounds known as secondary metabolites. These secondary metabolites demonstrated diverse biological properties such as anticancer, anti-diabetic, immunomodulatory, antimicrobial, anti-inflammatory, antiviral, anti-allergic, and antioxidative activities. This review presents bioactive compounds from the field of mushroom metabolite research and discusses important findings regarding bioactive compounds identified during the last five years (2015 - 2019).

• Journal of Microbiology and Biotechnology
• /
• v.32 no.5
• /
• pp.541-550
• /
• 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 Plant Biotechnology
• /
• v.30 no.3
• /
• pp.301-305
• /
• 2003

The effects of inorganic nitrogen sources such as KNO$_3$ and NH$_4$ NO$_3$ on cell growth and production of chlorogenic acid and eleutheroside E derivative were investigated in 5L bioreactor cultures of Eleutherococcus senticosus. The cell growth in the 1/2MS medium containing 15mMKNO$_{3}$. The fresh weight of cells harvested from bioreactor was affected by the concentration ratio of NO$_3$$^{[-10]}$ and NH$_4$$^{+}$ in culture medium. At the viewpoint of secondary metabolite production, the production of chlorogenic acid was affected by the concentration of NH$_4$$^{+}$ in the culture medium, but not by the total concentration of nitrogen sources in the culture medium. Futhermore, eleutheroside E derivative production was also affected by the concentration ratio of NO$_3$$^{[-10]}$ and NH$_4$$^{+}$ in the culture medium. Base on those results, it is suggested that cell growth and production of secondary metabolite(chlorogenic acid and eleutheroside E derivative) could be manipulated by controlling the total concentration of nitrogen sources and the concentration ratio of NO$_3$$^{[-10]}$ and NH$_4$$^{+}$ in the culture medium. medium.

• Journal of Microbiology and Biotechnology
• /
• v.31 no.1
• /
• pp.8-15
• /
• 2021

More and more available fungal genome sequence data reveal a large amount of secondary metabolite (SM) biosynthetic 'dark matter' to be discovered. Heterogeneous expression is one of the most effective approaches to exploit these novel natural products, but it is limited by having to clone entire biosynthetic gene clusters (BGCs) without errors. So far, few effective technologies have been developed to manipulate the specific large DNA fragments in filamentous fungi. Here, we developed a fungal BGC-capturing system based on CRISPR/Cas9 cleavage in vitro. In our system, Cas9 protein was purified and CRISPR guide sequences in combination with in vivo yeast assembly were rationally designed. Using targeted cleavages of plasmid DNAs with linear (8.5 kb) or circular (8.5 kb and 28 kb) states, we were able to cleave the plasmids precisely, demonstrating the high efficiency of this system. Furthermore, we successfully captured the entire Nrc gene cluster from the genomic DNA of Neosartorya fischeri. Our results provide an easy and efficient approach to manipulate fungal genomic DNA based on the in vitro application of Cas9 endonuclease. Our methodology will lay a foundation for capturing entire groups of BGCs in filamentous fungi and accelerate fungal SMs mining.

• Journal of Microbiology and Biotechnology
• /
• v.31 no.4
• /
• pp.601-609
• /
• 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
• /
• v.32 no.11
• /
• pp.1416-1426
• /
• 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
• /
• v.23 no.2
• /
• pp.177-183
• /
• 2013

Bacterial blight, an important and potentially destructive bacterial disease in rice caused by Xanthomonas oryzae pv. oryzae (Xoo), has recently developed resistance to the available antibiotics. In this study, mass spectrometry (MS)-based metabolite profiling and multivariate analysis were employed to investigate the correlation between timedependent metabolite changes and antimicrobial activities against Xoo over the course of Phomopsis longicolla S1B4 fermentation. Metabolites were clearly differentiated based on fermentation time into phase 1 (days 4-8) and phase 2 (days 10-20) in the principal component analysis (PCA) plot. The multivariate statistical analysis showed that the metabolites contributing significantly for phases 1 and 2 were deacetylphomoxanthone B, monodeacetylphomoxanthone B, fusaristatin A, and dicerandrols A, B, and C as identified by liquid chromatography-mass spectrometry (LC-MS), and dimethylglycine, isobutyric acid, pyruvic acid, ribofuranose, galactofuranose, fructose, arabinose, hexitol, myristic acid, and propylstearic acid were identified by gas chromatography-mass spectrometry (GC-MS)-based metabolite profiling. The most significantly different secondary metabolites, especially deacetylphomoxanthone B, monodeacetylphomoxanthone B, and dicerandrol A, B and C, were positively correlated with antibacterial activity against Xoo during fermentation.

• Microbiology and Biotechnology Letters
• /
• v.34 no.3
• /
• pp.211-215
• /
• 2006

AfsR2 is a global regulatory protein involved in the stimulation of secondary metabolite biosynthesis in various Streptomyces species including avermectin-producing S. avermitilis. Among several AfsR2-dependent genes identified from the comparative proteomics, the polyribonucleotide nucleotidyltransferase (PNP) and the glyceraldehyde-3-phosphate dehydrogenase (GPD) genes were previously proposed to regulate the actinorhodin production in S. lividans upon afsR2 over-expression positively and negatively, respectively. To show the biological significance of the PNP and GPD genes in the S. avermitilis strains, these two genes were functionally expressed in both the wild-type and the avermectin-overproducing mutant strains. The PNP gene expression stimulated secondary metabolite production in the wild-type S. avermitilis ATCC31267, but not in the avermectin-overproducing S. avermitilis ATCC31780. Interestingly, the GDP gene expression stimulated secondary metabolite production by 4-fold in the wild-type S. avermitilis ATCC31267 and by 2.5-fold in the avermectin-overproducing S. avermitilis ATCC31780, respectively. These results suggest that the biological significance of the afsR2-dependent PNP and GPD gene expressions on antibiotic biosynthetic regulation could be significantly different depending on Streptomyces species.

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