• Journal of Microbiology and Biotechnology
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• v.5 no.6
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• pp.335-340
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• 1995

Two types of Rhizoctonia solani esterases induced by cutin hydrolysate were partially purified by ammonium sulfate precipitation and gel filtration. The esterase I with hydrolyzing activity toward both ${\rho}-ni-trophenyl$ butyrate and ${\rho}-nitrophenyl$ palmitate and the esterase II with hydrolyzing activity toward only ${\rho}-ni-trophenyl$ butyrate were inhibited by ebelactone B, an esterase inhibitor produced by actinomycetes with $IC_{50}$ values of 0.01 and $0.09{\;}\mu\textrm{g}/l$, respectively. Spraying on rice seedling with ebelactone B at a concentration of $30{\;}\mu\textrm{g}/ml$ completely suppressed infection by R. solani. Ebelactone B could not protect the wounded rice seedling and did not show any inhibitory effect on the mycelial growth at a concentration of 1 mg/ml. These results indicate that ebelactone B, an esterase inhibitor protects rice plants from infection with R. solani by inhibition of penetration, not through fungitoxic or fungicidal effect.

• Journal of Microbiology and Biotechnology
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• v.29 no.10
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• pp.1624-1628
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• 2019

Banana planting altered microbial communities and induced the enrichment of Fusarium oxysporum in rhizosphere compared with that of forest soil. Diseased plant rhizosphere soil (WR) harbored increased pathogen abundance and showed distinct microbial structures from healthy plant rhizosphere soil (HR). The enriched taxon of Bordetella and key taxon of Chaetomium together with some other taxa showed negative associations with pathogen in HR, indicating their importance in pathogen inhibition. Furthermore, a more stable microbiota was observed in HR than in WR. Taken together, the lower pathogen abundance, specific beneficial microbial taxa and stable microbiota contributed to disease suppression.

• Journal of Microbiology and Biotechnology
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• v.10 no.2
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• pp.181-186
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• 2000

MAPI (microbial alkaline protease inhibitor) was isolated from cultrue broth of Streptomyces chromofuscus SMF28. The Ki values of MAPI for the representative serine proteases such as chymotrypsin and proteinase K were 0.28 and $0.63{\;}\mu\textrm{M}$, respectively, and for the cysteine proteases cathepsin B and papain were 0.66 and $0.28{\;}\mu\textrm{M}$, respectively. These data indicate that MAPI is not a potent selective inhibitor of serine or cysteine proteases. Progress curves for the inhibition of three proteases by MAPI exhibithe characteristic patterns; MAPI exhibited slow-binding inhibition of cathepsin B. It was rapidly associated with chymotrypsin before the addition of substrate and then reactivation of MAPI-inhibited enzyme was investigated in the presence of substrate. On the other hand, MAPI-proteinase K interaction was typical for those classical inhibitors. When MAPI was incubated with trypsin, there was an extensive reduction in the ingibitory activities of MAPI corresponding to 66.5% inactivation of MAPI, indicating that trypsin-like protease may play a role in the decrease of the inhibitory activity during cultivation.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.1
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• pp.52-58
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• 2004

An unstructured mathematical model for lactic acid fermentation was developed. This model was able to predict the inhibition effects of lactic acid and glucose and was con-firmed to be valid with various initial concentrations of lactic acid and glucose. Simulation of energy production was made using this mathematical model, and the relationship between the kinetics of energy metabolism and lactic acid production was also analyzed.

• 한국생물공학회:학술대회논문집
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• 2005.04a
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• pp.65-66
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• 2005

Anaerobic digestion is one of the well-known methods for biological treatment handling of concentrated organic matter such as swine $wastewater.^{1)} The anaerobic digestion can reduce organic loading but also hydrolyze non-biodegradable organic $matter.^{2)}$ The feces from the scrapper-type barn are usually collected to make compost and the urine is discarded with swine-slurry wastewater by ocean-dumping or treated by biological methods. The lagoon, aerobic digestion, anaerobic digestion, SBR, $A^{2}/O$, and UCT have been applied for treating swine $wastewater.^{3)} In this study, as a result of the analysis of swine wastewater, the total and soluble chemical oxygen demand was 130g/L and 60g/L, respectively. And the volatile fatty acid as chemical oxygen demand equivalent was 45g/L, which was 75% of soluble chemical oxygen demand. Before everything else, ammonia nitrogen concentration was 6.5 g/L. From biochemical acidogenic potential test, it was concluded that the enhanced acidification process to manage swine waste should be operated in the ammonia nitrogen concentration of less than 1.2 g/L. In the result of seeding ratio experiments with artificial $wastewater^{4)}, the lag period of acidogens was taken the long time because of the inhibition by the $ammonia^{5)}$, however no difference of period by the seeding ratio was not shown. The Haldane-based biokinetics were also evaluated using a method of fourth order Runge-Kutta $approximation.^{6,7)}$ The nonlinear least squares (NLLS) method with a 95% confidence interval was also used. The ranges of maximum microbial growth rate, ${/mu_{max}}$, and half saturation coefficient, $K_{s}$, for acidogenesis of various seeding ratio with artificial wastewater were 6.1 ~ 12.6 $d^{-1}$ and 45,000 ~ 53,500 mg glucose/L, respectively. Also, the methanogenic microbial yield coefficient, Y, and microbial decay rate coefficient, $k_{d}$, and inhibition substrate concentration, $K_{si}$, for the reactors were determined to be 0.32 ~ 0.465 ${/mu}g$/mg glucose; 0.42 ~ 1.01 $d^{-1}$ and 51,500 ~ 55,600 mg glucose/L, respectively.

• YAKHAK HOEJI
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• v.54 no.2
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• pp.106-111
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• 2010

The chemical structures of eight compounds purified from two plants (Polygala tenuifolia Willdenow and Dioscorea batatas Decene) were determined and their anti-microbial activity against three microbial strains (Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans) was tested. The three micro organisms were cultured in 96-well plates or Petri dishes without (control) or with the eight compounds added at concentrations of 100 to 0.01 ${\mu}M$ (wt/vol). The growth of the microorganisms in the medium was examined after a 24-h incubation. The inhibitory effect of each compound on the growth of the microorganisms was calculated from the optical density measured at 595 nm, turbidity, and size of the inhibition zone around the treated paper disc. The minimum inhiitory concentration (MIC) of compounds 4 to 7 against S. aureus was 0.08, 0.05, 1.3 and 0.02 ${\mu}M$, respectively, and 0.09, 0.1, 0.2 and 100 ${\mu}M$ against C. albicans. The $IC_{50}$ (50% inhibition) values of compounds 5 and 6 were 3.1 and 6.4 ${\mu}M$ against S. aureus, respectively, and 10 and 2.4 ${\mu}M$ against C. albicans. Therefore, compounds 4 to 6 were the most potent anti-microbial agents among the eight compounds tested.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.15 no.2
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• pp.53-79
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• 2002

To screen the effective materials for hair loss treatment, several natural extracts were tested using in vivo and in vitro test models. Firstly, all test materials were applicated onto the back skin of C57BL／6 mouse and then hair growth promoting effect was measured using hair growth index. As a result, Prunus mume, black bean, Brassica campestris subsp. black sesame and Rubi Fructus showed potent hair growth promoting effect, ranking as 1.5-2.0 of hair growth index. However, there were no plant extracts, which have remarkable potential of growth promotion of human hair dermal papilla cells cultured in vitro. In the experiments of 5${\alpha}$-reductase type Ⅱ inhibition assay, Prunus mume, Eriobotryae Folium showed effective potential to inhibit the activity of 5${\alpha}$-reductase type Ⅱ. To investigate the possible involvement of the effect of several plant extracts on the gene expression of growth factors in human hair dermal papilla cells, RT - PCR analyses were performed. However, there were no plant extracts, which have profound effect on the gene expression of several growth factors such as IGF-I, KGF, HGF and VEGF in the dermal papilla cells. Another tests for inhibition of microbial such as P. acne were also carried out to find whether these plant extracts have anti -microbial activities. Rubi Fructus showed anti -microbial effects on Propionibacterium acnes, which is believed as a pathogen of acne. Together, these results showed several plant extracts can be used for hair growth promotion.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.15 no.2
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• pp.80-103
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• 2002

To screen the effective materials for hair loss treatment, several natural extracts were tested using in vivo and in vitro test models. Firstly, all test materials were applicated onto the back skin of C57BL／6 mouse and then hair growth pormoting effect were measured using hair growth index As a result, Polygonum muitifiorum Thunb and Terrninalia chebula Retz. showed potent hair growth promoting effect, ranking as 1.5-2.0 of hair growth index. However, there were no plant extracts, which have remarkable potential of growth promotion of human hair dermal papilla cells cultured in vitro. In the experiments of 5${\alpha}$-reductase type Ⅱ inhibition assay, Morus alba L., Chaenomelis Fructus, Saussureae Radix, Angelicae Gigantis Radix, Polygonum multifiorum Thunb, and Angelica dahurica (Fischer) Bentham et Hooker f. showed effective potential to inhibit the activity of 5${\alpha}$-reductase type Ⅱ. To investigate the possible involvement of effects of several plant extracts on the gene expression of growth factors in human hair dermal papilla cells, RT-PCR analyses were performed. As a consequences, Mentha haplocalyx Briq., Cimicifuga foetida L., Eclipta prostrata (L.) L., Pinus densiflora S. et. Z, and Polygonum muitifiorum Thunb revealed the regulatory roles on the expression of growth factors such as IGF-I, KGF, HGF and VEGF in the dermal papilla cells. Another test for inhibition of microbial such as P. acne and P. ovale were also carried out to find whether these plant extracts have anti-microbial activities. Morus alba L. and Chaenomelis Fructus showed anti-microbial effects on Propionibacterium acnes, which is believed as a pathogen of acne. Together, these results showed several plant extracts can be used for hair growth promotion.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.5
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• pp.339-344
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• 2004

A method for synthesizing branched fructo-oligosaccharides (BFOS) with a high concentration of sucrose ($1{\~}3$ M) was developed using levansucrase prepared from Leuconortoc mesenteroides B-1355C. The degree of polymerization of oligosaccharides synthesized according to the present method ranged from 2 to over 15. The synthesized BFOS were stable at a pH ranges of 2 to 4 under $120^{\circ}C$. The percentage of BFOS in the reaction digest was $95.7\%$ (excluding monosaccharides; $4.3\%$ was levan). BFOS reduced the insoluble glucan formation by Streptococcus sobrinus on the surfaces of glass vials or stainless steel wires in the presence of sucrose. They also reduced the growth and acid productions of S, sobrinus. Oligosaccharides can be used as sweeteners for foods such as beverages requiring thermo- and acid-stable properties and 3s potential inhibitors of dental caries.

• Journal of Microbiology and Biotechnology
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• v.23 no.9
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• pp.1269-1278
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• 2013

Crack remediation on the surface of cement mortar using microbiological calcium carbonate ($CaCO_3$) precipitation (MICP) has been investigated as a microbial sealing agent on construction materials. However, MICP research has never acknowledged the antifungal properties of calcite-forming bacteria (CFB). Since fungal colonization on concrete surfaces can trigger biodeterioration processes, fungi on concrete buildings have to be prevented. Therefore, to develop a microbial sealing agent that has antifungal properties to remediate cement cracks without deteriorative fungal colonization, we introduced an antifungal CFB isolated from oceanic islands (Dokdo islands, territory of South Korea, located at the edge of the East Sea in Korea.). The isolation of CFB was done using B4 or urea-$CaCl_2$ media. Furthermore, antifungal assays were done using the pairing culture and disk diffusion methods. Five isolated CFB showed $CaCO_3$ precipitation and antifungal activities against deteriorative fungal strains. Subsequently, five candidate bacteria were identified using 16S rDNA sequence analysis. Crack remediation, fungi growth inhibition, and water permeability reduction of antifungal CFB-treated cement surfaces were tested. All antifungal CFB showed crack remediation abilities, but only three strains (KNUC2100, 2103, and 2106) reduced the water permeability. Furthermore, these three strains showed fungi growth inhibition. This paper is the first application research of CFB that have antifungal activity, for an eco-friendly improvement of construction materials.