• The Korean Journal of Mycology
• /
• v.44 no.4
• /
• pp.330-337
• /
• 2016

Streptomyces sp. A75 and A501 inhibited the mycelial growth of pathogenic Rhizoctonia solani and Pythium sp., which cause the ginseng disease known as damping-off. Three methods were evaluated for the control of these pathogens, using a mixture of the culture broths from Streptomyces sp. A75 and A501. The methods tested were seed dipping with 50-fold diluted broth, drenching of soil with 100-fold diluted broth after sowing, and combined seed dipping and drenching. These methods reduced the incidence of ginseng damping-off caused by R. solani by 81.3%, 84.8%, and 32.2% and that caused by Pythium sp. by 51.0%, 52.1%, and 75.3%, respectively. Based on these results, the combination of seed dipping and soil drenching after sowing using a mixture of the culture broths from Streptomyces sp. A75 and A501 effectively reduced the incidence of damping-off in ginseng.

• Mycobiology
• /
• v.45 no.1
• /
• pp.44-47
• /
• 2017

Ginseng damping-off, caused by the fungal pathogens Rhizoctonia solani and Pythium sp., is a critical disease in ginseng seedling. In a continuing effort to find microorganisms with the potential of acting as a biocontrol agent against Rhizoctonia damping-off, we found that a Streptomyces sp. A501 showed significant antifungal activity against Rhizoctonia solani. In field experiment to test the efficacy of Streptomyces sp. A501 in controlling ginseng damping-off, the incidence of damping-off disease was meaningfully reduced when ginseng seeds were soaked in the culture broth of Streptomyces sp. A501 before sowing. To perform characterization of the antifungal compound, we isolated it from the culture broth of strain A501 through Diaion HP-20 and silica gel column chromatographies and preparative high-performance liquid chromatography. The structure of the antifungal compound was assigned as fungichromin by spectroscopic methods, mainly nuclear magnetic resonance and electrospray ionization-mass analysis.

• Microbiology and Biotechnology Letters
• /
• v.18 no.5
• /
• pp.501-505
• /
• 1990

Streptomyces sp. KISl3 isolated from soil was found to produce low molecular weight thiol protease inhibitors. The protease inhibitor production was closely linked to the cell growth and regulated by growth condition. The inhibitor was purified from the culture broth through butanol extraction, silicagel 60 column chromatography, Sephadex LH-20 gel filtration and preparative HPLC. The inhibitor showed specific inhibitory activity to thiol protease such as papain, picin and bromelain. The mode of inhibition against papain to Hammersten casein as a substrate was non-competitive.

• Journal of Microbiology and Biotechnology
• /
• v.20 no.3
• /
• pp.501-505
• /
• 2010

1-Acetyl-$\beta$-carboline was isolated as an anti-MRSA agent from the fermentation broth of a marine actinomycete isolated from marine sediment. The producing strain was identified to be Streptomyces sp. by phylogenetic analysis of the 16S rRNA gene sequence. The anti-MRSA agent was isolated by bioactivity-guided fractionation of the culture extract by solvent partitioning, ODS open flash chromatography, and purification with a reversed-phase HPLC. Its structure was elucidated by extensive 2D NMR and mass spectral analyses. Combination of 1-acetyl-$\beta$-carboline with ampicillin exhibited synergistic antibacterial activity against MRSA.

• The Korean Journal of Food And Nutrition
• /
• v.19 no.4
• /
• pp.496-501
• /
• 2006

This study was to isolate a bacterium producing a alkaline protease from mud flats of the west seaside of Korea and to investigate the biochemical analysis of the alkaline protease producing from the isolate. The isolate was named as Gelidibacter sp. HK-1 based on 16S rRNA sequence, Gram staining and the photograph of electron microsceope. Optimum temperature for growth and pretense production of the isolate was $25^{\circ}C$. Growth of the isolate was reached at stationary phase after 10hrs followed by inoculation. Maximum activity of protease produced from the isolate was shown after 14hrs. Optimum temperature and pH for the protease activity were $45^{\circ}C$ and pH 9, respectively. Molecular weight of the pretense was about 50KD and the partial amino acid sequence of the pretense was Ala-Try-Ala-Leu-Asn-Thr-Ser-Val-Thr-Glu-Thr-Phe-Ala-Lys. The partial amino acid sequences of the protease showed significant homology with a pretense produced from Streptomyces avermitilis.

• The Korean Journal of Mycology
• /
• v.40 no.1
• /
• pp.44-48
• /
• 2012

Ginseng (Panax ginseng) is one of the most widely cultivated medicinal herb in Korea. However, yield losses reached up to 30~60 % due to various diseases during 3 or 5 years of ginseng cultivation. Therefore, successful production of ginseng roots depends primarily on the control of diseases. The objective of this study is to select potential multifunctional biocontrol agents from actinomycetes for the control of multiple ginseng diseases as an alternative to fungicides. Ninety three Streptomyces strains were selected and their ability to produce antibiotics, siderophore and lytic enzymes such as protease and cellulose were investigated. Eight of the isolates, strains A75, A501, 515, 523, A704, A1444, A3265 and A3283 produced cellulase and protease. These strains also produced siderophore and showed potent antifungal activity against Botrytis cinerea, Cylindrocarpon destructans, Collectotricum gloeosporioides, Phytophthora capsici and Rhizoctonia solani causing ginseng root rot.