• The Korean Journal of Physiology and Pharmacology
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• v.9 no.6
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• pp.333-339
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• 2005

B/K protein is a novel protein containing double C2-like domains. We examined the specific signaling pathway that regulates the transcription of B/K in PC12 cells. When the cells were treated with forskolin ($50{\mu}M$), B/K mRNA and protein levels were time-dependently decreased, reaching the lowest level at 3 or 4 hr, and thereafter returning to the control level. Chemicals such as dibutyryl-cAMP, cellpermeable cyclic AMP (cAMP) analogue and CGS21680, adenosine receptor $A_{2A}$ agonist, also repressed the B/K transcription. However, 1,9-dideoxyforskolin did not show inhibitory effect on B/K transcription, suggesting direct involvement of cAMP in the forskolin-induced inhibition of B/K transcription. Effect of forskolin, dibutyryl cAMP and CGS21680 was significantly reduced in PKA-deficient PC12 cell line (PC12-123.7). One cAMP-response element (CRE)-like sequence (B/K CLS) was found in the promoter region of B/K DNA, and electrophoretic mobility shift assay indicated its binding to CREM and CREB. Forskolin significantly suppressed the promoter activity in CHO-K1 cells transfected with the constructs containing B/K CLS, but not with the construct in which B/K CLS was mutated (AC：TG). Taken together, we suggest that the transcription of B/K gene in PC12 cells may be regulated by PKA-dependent mechanism.

• Microbiology and Biotechnology Letters
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• v.36 no.2
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• pp.121-127
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• 2008

A strain IDCC 9203 isolated from infant feces was identified as Lactobacillus johnsonii on the basis of 16S rDNA sequence analysis. L. johnsonii IDCC 9203 was highly resistant to acid (MRS broth at pH 2.3) and bile (MRS broth with 0.3% oxgall). The antibacterial activities of L. johnsonii IDCC 9203 was examined against Salmonella typhimurium KCTC 2054. The growth of S. typhimurium KCTC 2054 was inhibited by the cell-free culture supernatant (at pH 4.0) of L. johnsonii IDCC 9203 as well as by the respective control (MRS broth at pH 4.0). Antimicrobial effect against S. typhimurium KCTC 2054 of L. johnsonii IDCC 9203 was probably due to the lactic acid. By an in vitro cell adhesion model, L. johnsonii IDCC 9203 preincubated or coincubated with Caco-2 cells reduced the adhesion of S. typhimurium KCTC 2054 to Caco-2 cells by 74% or 47.1%, respectively. Also in an in vivo model, L. johnsonii IDCC 9203 was colonized in mice intestines which were disrupted by ampicillin treatment. Its proliferation in the mice intestines reduced abnormal salmonella growth from $10^9CFU/g$ feces to $10^5CFU/g$ feces as an indigenous level. The results obtained in this study suggest that L. johnsonii IDCC 9203 may be a potential probiotic strain.

• The Korean Journal of Mycology
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• v.40 no.2
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• pp.118-123
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• 2012

In order to develop environment friendly fungicide for the control of citrus green mold (Penicillium digitatum) using endophytic bacteria, the 21 bacterial isolates were isolated from citrus leaves in seven different orchards in Jeju Province. Among the 21 bacterial isolates, 5 bacterial isolates presented antifungal activity against green mold pathogen P. digitatum. The CB3 isolate, which showed the most strong antagonistic effect, was selected through opposite culture against the pathogen. The rod-shaped, gram-positive bacterium CB3 was identified as Bacillus velezensis based on morphological, physiological characteristics, 16S rDNA, and gyr A gene sequence analysis. The isolate CB3 showed strong antifungal activity against two citrus postharvest pathogen P. digitatum. Citrus fruits were treated by wound inoculation with P. digitatum pathogen, and the control efficacy of CB3 culture broth was 66.7% ($1{\times}10^8$ cfu/ml). In conclusion, The stability of CB3 and its strong antifungal activity also lead us to believe that it has potential for application as an environment friendly biological control agent.

• Microbiology and Biotechnology Letters
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• v.41 no.1
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• pp.33-43
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• 2013

A bacterium producing a fibrinolytic enzyme was isolated from Cheonggukjang. The bacterium was identified as a strain of Bacillus amyloliquefaciens by 16S rDNA analysis and designated as B. amyloliquefaciens HC188. The optimum culture medium appeared to be one containing 0.5% (w/v) maltose and 0.5% (w/v) soytone. Bacterial growth in the optimal medium at $37^{\circ}C$ reached the stationary phase after 27 h of incubation and the fibrinolytic enzyme showed optimum activity at 24 h. The enzyme was purified by 20-80% ammonium sulfate precipitation, CM Sepharose fast flow ion exchange chromatography, and Sephacryl S-200HR column chromatography. Its specific activity was 38359.3 units/mg protein and the yield was 5.5% of the total activity of the crude extracts. The molecular weight was 24.7 kDa and the amino acids of the N-terminal sequence were AQSVPYGVSQIKAPA. The fibrinolytic enzyme activity had an optimum temperature of $40^{\circ}C$ and an optimum pH of 8.0, and the enzyme was stable in the ranges $20-40^{\circ}C$ and pH 6.0-8.0. Enzyme activity was increased by $Ca^{2+}$ and $Co^{2+}$ but inhibited by $Cu^{2+}$, EDTA, and PMSF. It is suggested that the purified enzyme is a metallo-serine protease.

• Research in Plant Disease
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• v.23 no.1
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• pp.56-59
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• 2017

During growing season of 2011 to 2013, Sclerotinia rot symptoms consistently have been observed on basil in Yesan-gun, Chungcheongnam-do in Korea. The typical symptom formed initially brownish spot on leaf and stem, and then advancing margins, wilting the whole plant and blighting, eventually died. On the surface of diseased lesions was observed cottony, white, dense mat of mycelial growth, and sclerotia ($30-100{\mu}m$ diameter) formed on stem and leaf. Morphological and cultural characteristic on potato dextrose agar, color of colony was white and colorless chocolate, sclerotium of irregular shape of the oval was black and $5-50{\mu}m$ diameter in size. In pathogenicity test, necrosis and wilt of the inoculated stem were observed in all plants and the pathogen was reisolated from stems. On the basis of mycological characteristics, pathogenicity, and internal transcribed spacer rDNA sequence analysis, this fungus was identified as Sclerotinia sclerotiorum. This is the first report of Sclerotinia rot on basil caused by S. sclerotiorum in Korea.

• Journal of Microbiology and Biotechnology
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• v.21 no.9
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• pp.893-902
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• 2011

Endophytic fungi are little known for their role in gibberellins (GAs) synthesis and abiotic stress resistance in crop plants. We isolated 10 endophytes from the roots of field-grown soybean and screened their culture filtrates (CF) on the GAs biosynthesis mutant rice line - Waito-C. CF bioassay showed that endophyte GMH-1B significantly promoted the growth of Waito-C compared with controls. GMH-1B was identified as Penicillium minioluteum LHL09 on the basis of ITS regions rDNA sequence homology and phylogenetic analyses. GC/MS-SIM analysis of CF of P. minioluteum revealed the presence of bioactive $GA_4$ and $GA_7$. In endophyte-soybean plant interaction, P. minioluteum association significantly promoted growth characteristics (shoot length, shoot fresh and dry biomasses, chlorophyll content, and leaf area) and nitrogen assimilation, with and without sodium chloride (NaCl)-induced salinity (70 and 140 mM) stress, as compared with control. Field-emission scanning electron microcopy showed active colonization of endophyte with host plants before and after stress treatments. In response to salinity stress, low endogenous abscisic acid and high salicylic acid accumulation in endophyte-associated plants elucidated the stress mitigation by P. minioluteum. The endophytic fungal symbiosis of P. minioluteum also increased the daidzein and genistein contents in the soybean as compared with control plants, under salt stress. Thus, P. minioluteum ameliorated the adverse effects of abiotic salinity stress and rescued soybean plant growth by influencing biosynthesis of the plant's hormones and flavonoids.

• Korean Journal of Microbiology
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• v.52 no.2
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• pp.166-174
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• 2016

In order to find an efficient bacterial strain that can carry out nitrification and denitrification simultaneously, we isolated many heterotrophic nitrifying bacteria from wastewater treatment plant. One of isolates NS13 showed high removal rate of ammonium and was identified as Alcaligenes faecalis by analysis of its 16S rDNA sequence, carbon source utilization and fatty acids composition. This bacterium could remove over 99% of ammonium in a heterotrophic medium containing 140 mg/L of ammonium at pH 6-9, $25-37^{\circ}C$ and 0-4% of salt concentrations within 2 days. It showed even higher ammonium removal at higher initial ammonium concentration in the medium. A. faecalis NS13 could also reduce nitrate and nitrous oxide by nitrate reductase and nitrous oxide reductase, respectively, which was confirmed by detection of nitrate reductase gene, napA, and nitrous oxide reducase gene, nosZ, by PCR. One of metabolic intermediate of denitrification, $N_2O$ was detected from headspace of bacterial culture. Based on analysis of all nitrogen compounds in the bacterial culture, 42.8% of initial nitrogen seemed to be lost as nitrogen gas, and 46.4% of nitrogen was assimilated into bacterial biomass which can be removed as sludge in treatment processes. This bacterium was speculated to perform heterotrophic nitrification and aerobic denitrification simultaneously, and may be utilized for N removal in wastewater treatment processes.

• Journal of Microbiology and Biotechnology
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• v.26 no.8
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• pp.1383-1391
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• 2016

The fungal strain EML-DML3PNa1 isolated from leaf of white dogwood (Cornus alba L.) showed strong nematicidal activity with juvenile mortality of 87.6% at a concentration of 20% fermentation broth filtrate at 3 days after treatment. The active fungal strain was identified as Aspergillus oryzae, which belongs to section Flavi, based on the morphological characteristics and sequence analysis of the ITS rDNA, calmodulin (CaM), and β-tubulin (BenA) genes. The strain reduced the pH value to 5.62 after 7 days of incubation. Organic acid analysis revealed the presence of citric acid (515.0 mg/kg), malic acid (506.6 mg/kg), and fumaric acid (21.7 mg/kg). The three organic acids showed moderate nematicidal activities, but the mixture of citric acid, malic acid, and fumaric acid did not exhibit the full nematicidal activity of the culture filtrate of EML- DML3PNa1. Bioassay-guided fractionation coupled with ¹H- and ¹³C-NMR and EI-MS analyses led to identification of kojic acid as the major nematicidal metabolite. Kojic acid exhibited dose-dependent mortality and inhibited the hatchability of M. incognita, showing EC₅₀ values of 195.2 μg/ml and 238.3 μg/ml, respectively, at 72 h post-exposure. These results suggest that A. oryzae EML-DML3PNa1 and kojic acid have potential as a biological control agent against M. incognita.

• The Korean Journal of Mycology
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• v.46 no.2
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• pp.193-199
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• 2018

The fungus, Podosphaera pannosa, was identified in 1991 as the cause of powdery mildew symptoms on peach (Prunus persica var. persica) fruit from Korea based on the morphological characteristics of the conidial state. Recently, however, in Serbia and France, the cause of 'rusty spot' found on peach fruit was identified as P. leucotricha, and the cause of 'powdery mildew' on nectarine (Prunus persica var. nucipersica) fruit was identified as P. pannosa. To confirm the identity of the Korean pathogen, we collected four samples of powdery mildew from Korean peach fruit: three with the 'powdery mildew' symptom and one with the 'rusty spot' symptom. Morphological examination of the four samples confirmed P. pannosa as the pathogen. Internal transcribed spacer sequences of rDNA were analyzed for molecular characterization. A phylogenetic tree showed that the Korean isolates were clustered into a clade containing P. pannosa from Rosa species, with high sequence similarities of more than 99%. Thus, we showed that the powdery mildew and rusty spot symptoms on peach fruits from Korea are associated with P. pannosa.

• Molecules and Cells
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• v.45 no.12
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• pp.886-895
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• 2022

Malignant rhabdoid tumor (MRT) is a highly aggressive pediatric malignancy with no effective therapy. Therefore, it is necessary to identify a target for the development of novel molecule-targeting therapeutic agents. In this study, we report the importance of the runt-related transcription factor 1 (RUNX1) and RUNX1-Baculoviral IAP (inhibitor of apoptosis) Repeat-Containing 5 (BIRC5/survivin) axis in the proliferation of MRT cells, as it can be used as an ideal target for anti-tumor strategies. The mechanism of this reaction can be explained by the interaction of RUNX1 with the RUNX1-binding DNA sequence located in the survivin promoter and its positive regulation. Specific knockdown of RUNX1 led to decreased expression of survivin, which subsequently suppressed the proliferation of MRT cells in vitro and in vivo. We also found that our novel RUNX inhibitor, Chb-M, which switches off RUNX1 using alkylating agent-conjugated pyrrole-imidazole polyamides designed to specifically bind to consensus RUNX-binding sequences (5'-TGTGGT-3'), inhibited survivin expression in vivo. Taken together, we identified a novel interaction between RUNX1 and survivin in MRT. Therefore the negative regulation of RUNX1 activity may be a novel strategy for MRT treatment.