• Journal of Applied Biological Chemistry
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• v.66
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• pp.165-170
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• 2023

Isolation of the culture broth of a marine-derived Acremonium sp. CNQ-049 guided by HPLC-UV yielded compound 1 (3-phenethyl-2-phenylquinazolin-4(3H)-one), and its inhibitory activities against monoamine oxidases (MAOs), cholinesterases (ChEs), and β-secretase 1 (BACE1) were evaluated. Compound 1 was an effective selective MAO-B inhibitor with an IC₅₀ value of 9.39 µM and a selectivity index (SI) value of 4.26 versus MAO-A. In addition, compound 1 showed a potent selective butyrylcholinesterase (BChE) inhibition with an IC₅₀ value of 7.99 µM and an SI value of 5.01 versus acetylcholinesterase (AChE). However, compound 1 showed weak inhibitions against MAO-A, AChE, and BACE1. The Ki value of compound 1 for MAO-B was 5.22±1.73 µM with competitive inhibition, and the Ki value of compound 1 for BChE was 3.00±1.81 µM with mixed-type inhibition. Inhibitions of MAO-B and BChE by compound 1 were recovered by dialysis experiments. These results suggest that compound 1 is a dual-functional reversible inhibitor of MAO-B and BChE, that can be used as a treatment agent for neurological disorders.

• Korean Journal of Agricultural Science
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• v.8 no.2
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• pp.238-243
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• 1981

This experiment was carried out to study the availability of Korean peat as a main carrier material of rhizobial inoculant, using the alfalfa strain Rhizobium meliloti M 14 which was isolated in the previous report. Modification of powdered peat with calcium carbonate and other materials was studied; inoculation of the peat with culture broth, maturation of the mixture under different conditions, and survival of the strain in the peat culture was examined. The results obtained were as follows. 1. Peat produced in Pyongtak was highly acidic, pH 3.8, and addition of calcium carbonate by 14% was required for pH adjustment to 6.4. However the amount of calcium carbonate could be reduced by 4 to 8% when carbon or charcoal was mixed with the peat. 2. Viable number of the strain reached to $7-9{\times}10^9cells/g$ after 3 days, when inoculated with the culture broth of early stationary growth phase and matured in unsteriled peat of open trays; and the number in steriled peat was $1.1-6.2{\times}10^{10}cells/g$ after 5 days, when matured in closed bottles. 3. Survival of the strain was affected markedly by storage temperature, and positive effect of D-sorbitol on the viability was recognized at elevated temperatures, when added as an additional carbon source and moistening agent. Glycerol, sorbitol, or sodium lactate was utilized by the strain as a sole source of carbon, and the decimal reduction time of viable number in the peat culture was was found to be 8 to 9 weeks at $25^{\circ}C$ when these agents were added by 0.5%.

• Research in Plant Disease
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• v.8 no.3
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• pp.184-188
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• 2002

An antagonistic bacteria, Bacillus licheniformis Nl strain which effectively inhibited mycelial growth of gray mold rot pathogen, Botrytis cinerea was isolated from the rhizosphere of perilla crop. Powder soy formulation by B. lichentfomis Nl strain as a biocontrol agent was developed far the first time and estimated its control effect on perilla leaves in this study. First of all, far the mass production of antifungal metabolites of B. lichentfomis Nl strain in flask liquid culture, the most effective carbon and nitrogen source were selected as glucose and tryp-tone, respectively, For the formulation, vegetative biomass of B. licheniformis Nl strain from 5-day-old liquid culture in nutrient broth added glucose and tryptone was mixed with soy flour, rice flour glucose, FeSo$_4$~7$H_2O$, and MnCl$_2$. 4$H_2O$, and dried and pulverized. In plastic house test, powder soy formulation effectually controlled gray mold rot as the control value of 93.1 %, was more effective than chemical fungicide, benomyl showing the control value of 86.1%. Thus, development of powder soy formulation of B. lichentfomis Nl will aid large-scale application of biological control in field trials.

• Applied Biological Chemistry
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• v.42 no.1
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• pp.20-28
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• 1999

To improve Bacillus strains producing biopolymer, conditions for protoplast formation and regeneration were investigated in biopolymer producing Bacillus subtilis K-1 and lactose utilizing Bacillus coagulans. Bacillus subtilis K-1 mutant (SM-2) and Bacillus coagulans mutants (CM-12) were marked auxotrophic and antibiotics-resistant (SM-2) and an antibiotics-resistant mutants, respectively. To formate protoplasts derived from the mutants, conditions were established as follows. For B. subtilis mutant SM-2, its culture in mid-logarithmic phase was added with penicillin G (1.0 unit/ml) and further reacted for 1.5 hr. Cells were collected and then treated in lysis fluid (pH 7.0) containing 0.4 M sucrose and lysozyme $25\;{\mu}g/ml$ for 40 min at $37^{\circ}$. Protoplast formation was very successful (99.6%) and the ratio of cell wall regeneration was 2.4%. For Bacillus coagulans mutant CM-12, its mid-logarithmic phase culture was treated with penicillin G (0.3 unit/ml) and glycine (0.5%) for 1hr. Cells were collected and then resuspended in lysis buffer (pH 7.0) containing 0.6 M lactose and lysozyme $(300\;{\mu}g/ml)$ for 30 min at $37^{\circ}$. Protoplast formation was also successful (90.8%) and cell wall regeneration ratio was similar to SM-2 (2.2%). To improve regeneration frequency, regeneration medium was obtained as followed condition,. Cell wall regeneration was improved 2-4 folds with 5.1% for B. subtilis SM-2 and 10.3% for B. coagulans CM-12 when protoplasts mixed with soft top agar(0.4%) was overlaid onto trypticase soy broth medium containing 0.4 M sucrose, 0.7% casamino acid, 1% PVP, 25 mM $MgCl_2,\;25\;mM\;CaCl_₂$ and 1.5% agar.

• Korean Journal of Microbiology
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• v.42 no.3
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• pp.185-194
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• 2006

The aim of this study was to identify the bacteria isolated from endodontic lesions by cell culture and to determine the antimicrobial susceptibility of them against 8 antibiotics. The necrotic pulpal tissues were collected from 27 infected root canals, which were diagnosed as endodontic infection. Samples were collected aseptically from the infected pulpal tissue of the infected root canals using a barbed broach and a paper point. The cut barbed broaches and paper points were transferred to an eppendorf tube containing $500{\mu}l\;of\;1{\times}PBS$. The sample solution was briefly mixed and plated onto a BHI-agar plate containing 5% sheep blood. The agar plates were incubated in a $37^{\circ}C$ anaerobic chamber for 2 to 5 days. The bacteria grown on the agar plates were identified by comparison of 16S rRNA gene (rDNA) sequencing method at the species level. To test the sensitivity of the bacteria isolated from the infected root canals against 8 antibiotics, minimum inhibitory concentrations (MIC) were determined using broth dilution assay. The data showed that 101 bacterial strains were isolated and were identified. Streptococcus spp. (29.7%) and Actinomyces spp. (21.8%) were predominantly isolated. The 9 strains were excluded in antimicrobial susceptibility test because they were lost during the experiment or were not grown in broth culture. The percentage of bacteria susceptible for each antibiotic in this study was clindamycin, 87.0% (80 of 92); tetracycline, 75.0% (69 of 92); cefuroxime axetil, 75.0% (69 of 92); amoxicillin + clavulanic acid (5:1), 71.7% (66 of 92); penicillin G, 66.3% (61 of 92); erythromycin, 66.3% (61 of 92); amoxicillin, 44.6% (41 of 92); and ciprofloxacin, 31.5% (29 of 92). The susceptibility pattern of 8 antibiotics was dependent on the host of the bacteria strains rather than the kinds of bacterial species. These results indicate that antibiotic susceptibility test should be performed when antibiotics are needed for the treatment of infected root canals.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.4
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• pp.195-203
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• 2006

An antagonistic strain, Burkholderia MP-1, showed antimicrobial activity against various filamentous plant pathogenic fungi, yeasts and food borne bacteria (Gram-positive and Gram-negative). The nucleotide sequence of the 16S rRNA gene (1491 pb) of strain MP-1 exhibited close similarity (99-100%) with other Burkholderia 16S rRNA genes. Isolation of the antibiotic substances from culture broth was fractionated by ethyl acetate (EtOAc) solvent and EtOAc-soluble acidic fraction. The antibiotic substances were purified through a silica gel, Sephadex LH-20, ODS column chromatography, and high performance liquid chromatography, respectively. Four active substances were identified as phenylacetic acid, hydrocinnamic acid, 4-hydroxyphenylacetic acid and 4-hydroxyphenylacetate methyl ester by gas chromatographic-mass spectrum analysis. The minimum inhibition of concentration (MIC) of each active compound inhibited the growth of the microorganisms tested at 250 to $2500{\mu}g\;ml^{-1}$. The antimicrobial activity of crude acidic fraction at 1 mg of dry weight per 6 mm paper disc was more effective than authentic standard mixture (four active substances were mixed with the same ratio as acidic fraction) over a wide range of bacterial test.

• Journal of Food Hygiene and Safety
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• v.19 no.3
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• pp.151-160
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• 2004

Enterococcus faecium MJ5-14 isolated from Meju produced a bacteriocin, which was antagonistic towards Listeria monocytogenes. Bacteriocin activity reached a maximum (640 BU/mL) after incubation for 12 hr, the early stationary phase, then dropped after the late stationary phase. Bacterocin of E. faecium MJ5-14 was extremely active against a wide range of Listeria species, including L. monocytogenes with sensitives up to about 640 BU/mL. In case of mixed culture with 105 CFU/mL L. monocytogenes and 105 CFU/mL E. faecium MJ5-14, the inhibitory effect against L. monocytogenes at $37^{\circ}C$ was higher than at $25^{\circ}C$. The mode of action was identified as bactericidal, because the addition of 100 BU/mL this bacteriocin to cell suspensions of L. monocytogenes KCTC 3569, led to a marked decrease in the number of viable cells. Further, when held in contact with bacteriocin of E. faecium MJ15-14 for 12 hr, L. monocytogenes KCTC 3569 displayed the disruption of the cells and an important efflux of the intracellular material.

• Korean Journal of Food Science and Technology
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• v.28 no.6
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• pp.1089-1094
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• 1996

The in vivo effect of tyrosinase inhibitors in the melanogenesis of gold fish (jet black color) was evaluated by measuring surface color and observing melanin pigment. The fish was firstly cultivated in 0.9% NaCl solution for 1 week to induce melanogenesis, and then, it was transferred to each treatment group containing tyrosinase inhibitor. The fish was grouped into control. food additive group (addition of 5 mM glutathione, 5 mM cysteine, and 1 mM benzoic acid), microbial inhibitor group (addition of culture broth of Aspergillus oryzae in shiitake and glucose medium), and plant extract group (addition of the mixed extracts of green tea, beet, red chicory, and nameko). After 6 days, the fish was anesthetized by electric shock, and color of pectoral region, lateral region, and dorsal fin was measured. Hunter's L and b values of treated group were generally higher than those of control group, indicating that the tyrosinase inhibitors could inhibit the melanogenesis of the fish. Effect of plant extract was apparent, though relatively weak, not because it did not work in vivo, but because a sufficient amount of extract could not be added to fish globes. If a large amount of extract was added, fish gradually died due to a microbial contamination. Microscopic observation of melanin in lateral scale and dorsal fin showed that in the treated groups with tyrosinase inhibitors, the number of melanophore per unit area and the size of one melanophore decreased.

• KSBB Journal
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• v.25 no.6
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• pp.520-526
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• 2010

In this work we have investigated the production of catalase from Bacillus sp. strains, which were screened and identified from soil. These strains were cultivated in shaking flasks with tryptic soy broth (TSB) at $30^{\circ}C$ and 200 rpm. Effects of the temperature and pH on the stability of the native catalase and whole cell viability were studied in the temperature range of $25-60^{\circ}C$ and the pH range of 7-13. Korean natural zeolite was added to culture medium and mixed with microorganisms for 24 hours. The native catalase maintained its activity over $50^{\circ}C$. The enzyme acitiviy of the catalase from Bacillus flexus BKBChE-3 was highest among the Bacillus sp. strains studied. Bacillus flexus BKBChE-3 and immobilized Bacillus cells have survived under extreme conditions of over $50^{\circ}C$ and pH 12. 60 mL of 10.5 mM $H_2O_2$ solution were entirely removed within 1 hour with catalase produced from Bacillus sp. on the flask. When Bacillus cells were immobilized on Korean natural zeolite, colony forming unit of Bacillus flexus BKBChE-3 was increased and high efficiency of hydrogen peroxide removal was observed.