• Journal of Microbiology and Biotechnology
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• v.31 no.9
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• pp.1218-1230
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• 2021

Cold-adapted plant growth-promoting bacteria (PGPB) with multiple functions are an important resource for microbial fertilizers with low-temperature application. In this study, culturable cold-adapted PGPB strains with nitrogen fixation and phosphorus solubilization abilities were isolated. They were screened from root and rhizosphere of four dominant grass species in nondegraded alpine grasslands of the Qilian Mountains, China. Their other growth-promoting characteristics, including secretion of indole-3-acetic acid (IAA), production of siderophores and ACC deaminase, and antifungal activity, were further studied by qualitative and quantitative methods. In addition, whether the PGPB strains could still exert plant growth-promoting activity at 4℃ was verified. The results showed that 67 isolates could maintain one or more growth-promoting traits at 4℃, and these isolates were defined as cold-adapted PGPB. They were divided into 8 genera by 16S rRNA gene sequencing and phylogenetic analysis, of which Pseudomonas (64.2%) and Serratia (13.4%) were the common dominant genera, and a few specific genera varied among the plant species. A test-tube culture showed that inoculation of Elymus nutans seedlings with cold-adapted PGPB possessing different functional characteristics had a significant growth-promoting effect under controlled low-temperature conditions, including the development of the roots and aboveground parts. Pearson correlation analysis revealed that different growth-promoting characteristics made different contributions to the development of the roots and aboveground parts. These cold-adapted PGPB can be used as excellent strain resources suitable for the near-natural restoration of degraded alpine grasslands or agriculture stock production in cold areas.

• The Plant Pathology Journal
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• v.37 no.1
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• pp.24-35
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• 2021

Blue mold caused by Penicillium expansum is one of the most significant postharvest diseases of apples. Some microorganisms associated with the surface of ripening apples possess the ability to inhibit the growth of P. expansum. However, the existing literature about their colonization in the stages before ripening is not explored in depth. This study aims to characterize the antagonistic capacity of bacterial populations from five fruit development stages of 'Royal Gala' apples. The results have shown that the density of the bacterial populations decreases throughout the ripening stages of fruit (from 1.0 × 105 to 1.1 × 101 cfu/㎠). A total of 25 bacterial morphotypes (corresponding to five genera identified by 16S RNA) were differentiated in which Bacillus stood out as a predominant genus. In the in vitro antagonism tests, 10 Bacillus strains (40%) inhibited the mycelial growth of P. expansum from 30.1% to 60.1%, while in fruit bioassays, the same strains reduced the fruit rot ranging from 12% to 66%. Moreover, the bacterial strains with antagonistic activity increased in the ripening fruit stage. B. subtilis subsp. spiziennii M24 obtained the highest antagonistic activity (66.9% of rot reduction). The matrix-assisted laser desorption ionization-time of flight mass spectrometry analysis revealed that bacteria with antagonistic activity produce anti-fungal lipopeptides from iturin and fengycin families.

• The Plant Pathology Journal
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• v.38 no.4
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• pp.313-322
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• 2022

Seed-borne pathogens in crops reduce the seed germination rate and hamper seedling growth, leading to significant yield loss. Due to the growing concerns about environmental damage and the development of resistance to agrochemicals among pathogen populations, there is a strong demand for eco-friendly alternatives to synthetic chemicals in agriculture. It has been well established during the last few decades that plant seeds harbor diverse microbes, some of which are vertically transmitted and important for plant health and productivity. In this study, we isolated culturable endophytic bacteria and fungi from soybean seeds and evaluated their antagonistic activities against common bacterial and fungal seed-borne pathogens of soybean. A total of 87 bacterial isolates and 66 fungal isolates were obtained. Sequencing of 16S rDNA and internal transcribed spacer amplicon showed that these isolates correspond to 30 and 15 different species of bacteria and fungi, respectively. Our antibacterial and antifungal activity assay showed that four fungal species and nine bacterial species have the potential to suppress the growth of at least one seed-borne pathogen tested in the study. Among them, Pseudomonas koreensis appears to have strong antagonistic activities across all the pathogens. Our collection of soybean seed endophytes would be a valuable resource not only for studying biology and ecology of seed endophytes but also for practical deployment of seed endophytes toward crop protection.

• Applied Biological Chemistry
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• v.46 no.3
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• pp.235-239
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• 2003

Thirteen sesquiterpene lactones isolated from the flower of Chrysanthemum coronarium L., which has been widely cultivated in Korea as a vegetable for a long time, were investigated their antimicrobial activities against eight bacteria and five phytopathogenic fungi. The antimicrobial activities of dihydrochrysanolide (6) and 1-epi-dihydrochrysanolide (7) showed strong activities against all the bacteria such as Bacillus subtilis, Bacillus cereus, Staphylococcus aureus and Vibrio parahaemolyticus. Especially, Staphylococcus aureus was investigated that have very strong antibacterial activity to $1.56\;{\mu}g{\cdot}disc^{-1}$, respectively. Also, most of sesquiterpene lactones, which have ${\alpha}-methylene-{\gamma}-butyrolactone$ group, were exhibited strong activity to Gram(+) bacteria than Gram(-) bacteria. In the antifungal test, Rhizoctonia solani and Phytophthora capsici known as phytopathogenic fungi have exhibited all extensive activity about compounds that have ${\alpha}-methylene-{\gamma}-butyrolactone$ group.

• Microbiology and Biotechnology Letters
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• v.38 no.3
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• pp.255-262
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• 2010

Strain BCNU 2001 was isolated from soil samples collected from Tea-baek Mountain area. The biochemical characteristics and 16S ribosomal RNA gene sequences of the isolate revealed that the strain belonged to the Pseudomonas aeruginosa. The supernatants had an antimicrobial effect on various kind of bacteria and fungi. Especially BCNU 2001 was able to greatly inhibit the growth of Micrococcus luteus, Proteus mirabilis, Proteus vulgaris, and Aspergillus niger, and its inhibition zone was measured as 18.5 mm against Micrococcus luteus, 19.0mm against Proteus mirabilis, 17.0mm against Proteus vulgaris, and 13.5 mm against Aspergillus niger, respectively. Hexane and dichloromethane extracts of BCNU 2001 exhibited significant activity against bacteria, and dichloromethane and ethylacetate extracts showed significant activity against fungi. Pseudomonas strain BCNU 2001 was also determined to have antimicrobial peptide against various microorganisms including Gram positive bacteria, Gram negative bacteria and fungi. The obtained results may provide preliminary support for the usefulness of Pseudomonas strain BCNU 2001.

• Journal of Mushroom
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• v.21 no.3
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• pp.190-193
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• 2023

To cultivate pine mushroom (Tricholoma matsutake) artificially, co-cultivation with microorganisms has been introduced. Here, experiments were performed to assess the growth-promoting effect of bacteria on T. matsutake mycelia. Bacteria were isolated from soil samples collected in Yangyang County, Korea. Four of the bacterial isolates (Y22_B06, Y22_B11, Y22_B18, and Y22_B22) exhibited a growth-promoting effect on T. matsutake mycelia (154.67%, 125.91%, 134.06%, and 158.28%, respectively). To analyze the characteristics of the bacteria, especially the antifungal activity, 𝛼-amylase and cellulase activity assays were performed. In comparison with the controls, the isolated bacteria exhibited low 𝛼-amylase and cellulase activity. 16S rRNA gene sequencing was performed to identify the four bacterial isolates. The isolates belonged to the Terrabacteria group and were identified as Microbacterium paraoxydans, Paenibacillus castaneae, Peribacillus frigoritolerans, and P. butanolivorans. These bacterial isolates are expected to have contributed to the growth promotion of T. matsutake mycelia and the artificial cultivation of T. matsutake.

• Journal of the Korean Chemical Society
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• v.58 no.3
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• pp.258-266
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• 2014

Single crystals of cobalt(II) and nickel(II) complexes of 4-nitrobenzoic acid have been successfully grown by gel diffusion technique. The grown crystals were characterized by elemental analysis, FT-IR and UV-Visible spectroscopy. The structure of the grown crystals was elucidated using single crystal X-ray diffraction studies. The title compounds $[Co(Pnba)_2(H_2O)_4]{\cdot}2H_2O$ 1 and $[Ni(Pnba)_2(H_2O)_4]{\cdot}2H_2O$ 2 where PnbaH=4-nitrobenzoic acid, crystallize in centrosymmetric triclinic space group P-1. Magnetic susceptibility measurements reveal that the compounds are paramagnetic in nature. The mechanical strength of the grown crystals was determined by Vicker's microhardness studies. The ligand (4-nitrobenzoic acid) and the complexes have been screened for their biological activity against various bacteria and fungi. The activity data show that the biological activity of the complexes is higher than that of the ligand.

• Mycobiology
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• v.38 no.1
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• pp.39-45
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• 2010

White rot, which is caused by Sclerotium cepivorum, is a lethal disease affecting green onions. Three different types of nanosilver liquid (WA-CV-WA13B, WA-AT-WB13R, and WA-PR-WB13R) were tested in several different concentrations on three types of media to assess their antifungal activities. Results from in vitro experiments showed that all three of the nano-silver liquids had more than 90% inhibition rates at a concentration of 7 ppm. Greenhouse experiments revealed that all of the nano-silver liquids increased biomass and dry weights, and there were minimal changes in the population of various bacteria and fungi from the soil of greenhouse-cultivated green onions. In addition, a soil chemical analysis showed that there were minimal changes in soil composition.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48
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• pp.41-48
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• 2003

The number of natural products obtained from plants has now reached over 100,000 and new chemical compounds are being discovered ever year. Medicinal and Aromatic plants and their extracts have been used for centuries to relieve pain, aid healing, kill bacteria and insects are important as the antifungal and anti-herbivore agents with further compounds being involved in the symbiotic associations. Although their functions in plants have not been fully established, it is Known that some substances have growth regulatory properties while others are involved in pollination and seed dispersal. The complex nature of these chemicals are usually produced in various types of secretory structures which is an important character of a plant family and also influenced and controlled by genetic and ecological factors. Detailed anatomical description of these structures ave relevant to the market value of the plants, the verification of authenticity of a given species and for the detection of substitution or adulteration. Volatile oils are used for their therapeutic action for flavoring of lemon, in perfumery of rose or as starting materials for the synthesis of other compounds of turpentine. For therapeutic purposes they are administered as inhalations of eucalyptus oil, peppermint oil, as gargles and mouthwashes of thymol and transdermally many essential oils including those of lavender, etc. With these current trend for using volatile components in essential oil will be increasing in the future in Korea and in the world as well.

• Microbiology and Biotechnology Letters
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• v.25 no.1
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• pp.30-36
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• 1997

To genetically breed powerful multifunctional antagonistic bacteria, the urease gene of alkalophilic Bacillus pasteurii was transferred into Bacillus subtilis YB-70 which had been selected as a powerful biocontrol agent against root-rotting fungus Fusarium solani. Urease gene was inserted into the HindIII site of pGB215-110 and designated pGU266. The plasmid pGU266 containing urease gene was introduced into the B. subtilis YB-70 by alkali cation transformation system and the urease gene was very stably expressed in the transformant of B. subtilis YB-70(pGU266). The optimal conditions for the transfomation were also evaluated. From the in vitro antibiosis tests against F. solani, the antifungal activity of B. subtilis YB-70 containing urease gene was much efficient than that of the non-transformed strain. Genetic improvement of B. subtilis YB-70 by transfer of urease gene for the efficient control seemed to be responsible for enhanced plant growth and biocontrol efficacy by combining its astibiotic action and ammonia producing ability.