• 농업과학연구
• /
• 제37권2호
• /
• pp.255-260
• /
• 2010

Rusty root, the browning disease on ginseng, decreases quality and value. Recent studies indicated that endophytic bacteria could be a possible cause of rusty root. Actinomycetes antagonistic to the rusty-root-causing bacteria were isolated from soil. Twenty nine out of 932-isolates of Actinomycetes from soil showed antibacterial activity against Agrobacterium tumefaciens and Pseudomonas veronii an endophytic isolate in ginseng. The strongest antibacterial strain(ATO4O104) was classified based on 16S rDNA sequence. The Actinomycetes strain, ATO4O104, isolated in soil of USA volcano national park was identified as Streptomyces adephospholyticus. To test plant toxicity, radish seeds were sprouted with the culture of S. adephospholyticus and it did not show any harmful effect. The butanol partition out of n-hexane, ethyl acetate, butanol, and water partions showed the highest antibacterial activity.

• The Plant Pathology Journal
• /
• 제17권6호
• /
• pp.371.3-371
• /
• 2001

• 한국식물병리학회:학술대회논문집
• /
• 한국식물병리학회 2002년도 총회 및 추계학술발표회
• /
• pp.47.2-48
• /
• 2002

• 한국작물학회:학술대회논문집
• /
• 한국작물학회 2018년도 추계학술대회
• /
• pp.121-121
• /
• 2018

• 한국식물병리학회:학술대회논문집
• /
• 한국식물병리학회 2002년도 총회 및 추계학술발표회
• /
• pp.50.1-50
• /
• 2002

• 한국식물병리학회:학술대회논문집
• /
• 한국식물병리학회 2002년도 총회 및 추계학술발표회
• /
• pp.52.2-52
• /
• 2002

• 한국식물병리학회:학술대회논문집
• /
• 한국식물병리학회 2002년도 총회 및 추계학술발표회
• /
• pp.52.3-53
• /
• 2002

• Journal of Microbiology and Biotechnology
• /
• 제27권7호
• /
• pp.1249-1256
• /
• 2017

In our search for new sources of bioactive secondary metabolites from Streptomyces sp., the ethyl acetate extracts from endophytic Streptomyces SUK 25 afforded five active diketopiperazine (DKP) compounds. The aim of this study was to characterize the bioactive compounds isolated from endophytic Streptomyces SUK 25 and evaluate their bioactivity against multiple drug resistance (MDR) bacteria such as Enterococcus raffinosus, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumanii, Pseudomonas aeruginosa, and Enterobacter spp., and their cytotoxic activities against the human hepatoma (HepaRG) cell line. The production of secondary metabolites by this strain was optimized through Thornton's medium. Isolation, purification, and identification of the bioactive compounds were carried out using high-performance liquid chromatography, high-resolution mass liquid chromatography-mass spectrometry, Fourier transform infrared spectroscopy, and nuclear magnetic resonance, and cryopreserved HepaRG cells were selected to test the cytotoxicity. The results showed that endophytic Streptomyces SUK 25 produces four active DKP compounds and an acetamide derivative, which were elucidated as $cyclo-({\text\tiny{L}}-Val-{\text\tiny{L}}-Pro)$, $cyclo-({\text\tiny{L}}-Leu-{\text\tiny{L}}-Pro)$, $cyclo-({\text\tiny{L}}-Phe-{\text\tiny{L}}-Pro)$, $cyclo-({\text\tiny{L}}-Val-{\text\tiny{L}}-Phe)$, and N-(7-hydroxy-6-methyl-octyl)-acetamide. These active compounds exhibited activity against methicillin-resistant S. aureus ATCC 43300 and Enterococcus raffinosus, with low toxicity against human hepatoma HepaRG cells. Endophytic Streptomyces SUK 25 has the ability to produce DKP derivatives biologically active against some MDR bacteria with relatively low toxicity against HepaRG cells line.

• Journal of Microbiology and Biotechnology
• /
• 제26권5호
• /
• pp.946-952
• /
• 2016

The eglS gene in Bacillus amyloliquefaciens encodes an endo-β-1,4-glucanase that belongs to glycosyl hydrolase family 5. In this study, a disruption mutant of gene eglS was constructed to examine its role in bacterial adaptation in plants. The mutant TB2_k, eglS gene inactivated bacterial strain, was remarkably impaired in extracellular cellulase activity. When inoculated on Brassica campestris, the TB2_k population was reduced by more than 60% compared with the wild-type strain in the root, stem, and leaf tissues. Overexpression of eglS in the wild-type strain increased the bacteria population in the plant tissues. Further studies revealed that the transcription level of eglS was correlated with bacterial population. These data demonstrate that endo-β-1,4-glucanase of B. amyloliquefaciens is required for its optimal endophytic colonization.

• Journal of Applied Biological Chemistry
• /
• 제62권4호
• /
• pp.441-446
• /
• 2019

The assortment of endophytic lactic acid bacteria (LAB) in kimchi derives from its raw vegetables, which include Chinese cabbage, radish, welsh onion, onion, garlic, red pepper, and ginger. These vegetables were examined during mulkimchi fermentation using gene-specific multiplex polymerase chain reaction and 16S ribosomal RNA sequence analysis. Sixteen species from five LAB genera (Leuconostoc, Lactobacillus, Lactococcus, Pediococcus, and Weissella) appeared in the raw kimchi materials. Interestingly, nine LAB species were identified in mulkimchi on fermentation day 0 as follows: Leuconostoc carnosum, Leuconostoc citreum, Leuconostoc gelidum, Leuconostoc inhae, Leuconostoc mesenteroides, Lactobacillus plantarum, Lactobacillus sakei, Lactococcus lactis, and Weissella confusa. Seven additional LAB species were present in mulkimchi at fermentation day 9 as follows: Leuconostoc gasicomitatum, Leuconostoc kimchii, Lactobacillus brevis, Lactobacillus curvatus, Lactobacillus pentosus, Pediococcus pentosaceus, and Weissella koreensis. These species corresponded completely with the LAB in kimchi vegetables. Wei. confusa was the predominant LAB during early fermentation (pH 6.20 to 4.98 and acidity 0.20 to 0.64%), while Lac. sakei, Lac. plantarum, and Wei. koreensis became dominant later in fermentation (pH 4.98 to 3.88 and acidity 0.64 to 1.26%). These results collectively demonstrate that the LAB involved in mulkimchi fermentation originates from the raw vegetables examined.