• KSBB Journal
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• v.15 no.6
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• pp.573-577
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• 2000

The optimum fermentation conditions for the production of cellulose by a newly isolated Acetobacter sp. A9 were determined in static cultures. The strain was able to produce cellulose at $25-30^{\circ}C$ with a maximum at $30^{\circ}C$. Cellulose production occurred at pH 6.5-8.0 with a maximum at pH 6.5. The optimal culture medium was found to consists of 1.0% glucose, 1.0% yeast extract, 0.7% polypeptone, 0.15% acetic acid and 0.02% succinic acid. Cellulose production by Acetobacter sp. A9 followed the growth curve. Highest cellulose production, under optimum conditions, was $24.1m^2$, although this strain typically produced only $12.1 g/m^2$ in the basic medium. Cellulose production also depended on the depth and volume of the medium.

• Korean Journal of Environmental Biology
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• v.29 no.4
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• pp.321-325
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• 2011

The mutant strain M6 derived from Acetobacter sp. A9, which produces high levels of the bacterial cellulose derived by random mutagenesis with N-methyl-N'-nitro-N-nitrosoguanidine or UV treatment, was selected by a Hestrin and Schramm medium (HSB) plate assay. The characterization of the cellulose production was studied in flask culture to improve the productivity of bacterial cellulose by $Acetobacter$ sp. A9 and mutant strain M6. The yield of cellulose production was superior to mutant M6 than $Acetobacter$ sp. A9. Cellulose was produced 0.12 g $L^{-1}$ by $Acetobacter$ sp. A9 at HS medium and the mutant M6 produced the cellulose 6.95 g $L^{-1}$at HS medium. Strain M6 produced less amount of gluconic acid than A9, thus showing that cellulose production is negatively relted with the gluconic acid production.

• Microbiology and Biotechnology Letters
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• v.49 no.3
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• pp.329-336
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• 2021

Cellulophga sp. J9-3, is a gram-negative, aerobic marine bacterium belonging to the family Flavobacteriaceae. In addition to cellulose degradability, the J9-3 strain is also capable of hydrolyzing agar in the solid and liquid medium, and the production of agarase in the presence of agarose can be remarkably induced by the bacterium. From the cell culture broth of Cellulophga sp. J9-3, ammonium sulfate precipitation and three kinds of column chromatography were successively performed to purify a specific agarase protein, the AgaJ93. Purified AgaJ93 showed the strongest hydrolyzing activity towards agarose (approximately 22%), and even displayed activity towards starch. AgaJ93 hydrolyzed agarose into neoagarotetraose and neoagarohexaose via various oligosaccharide intermediates, indicating that AgaJ93 is an endo-type β-agarase. AgaJ93 showed maximum activity at a pH of 7.0 and temperature of 35 ℃. Its activity increased by more than six times in the presence of Co²⁺ ions. The N-terminal sequence of AgaJ93 showed 82% homology with the heat-resistant endo-type β-agarase Aga2 of Cellulophaga sp. W5C. However, the biochemical properties of the two enzymes were different. Therefore, AgaJ93 is expected to be a novel agarose, different from the previously reported β-agarases.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.12
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• pp.2565-2573
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• 2002

A basic research was performed to ensure the usefulness of Small Punch-creep(SP-creep) test for residual life evaluation of heat resistant components effectively. This paper presents analytical results of initial stress and strain distributions in SP specimen caused by constant loading for SP-creep test and its experimental correlations with uniaxial creep(Ten-creep) test on 9Cr1MoVNb steel. It was shown that the initial maximum equivalent stress, ${\sigma}_{eq{\cdot}max}$ from FE analysis was correlated with steady-state equivalent creep strain rate, ${\epsilon}_{qf-ss'}$ rupture time, $t_r$, activation energy, Q and Larson-Miller Parameter, LMP during SP-creep deformation. The simple correlation laws, ${\sigma}_{sp}-{\sigma}_{TEN}$, $P_{sp}-{\sigma}_{TEN}\; and\; Q_{sp}-Q_{TEN}$ adopted to established a quantitative correlation between SP-creep and Ten-creep test data. Especially, the activation energy obtained from SP-creep test is linearly related to that from Ten-creep test at $650^{\circ}C$ as follows : $Q_{SP-P}\;{\risingdotseq}\;1.37 \;Q_{TEN},\; Q_{SP-{\sigma}}{\risingdotseq}1.53\; Q_{TEN}$.

• Research in Plant Disease
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• v.9 no.3
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• pp.174-178
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• 2003

Pseudomonas sp. antagonistic to Colletotrichum truncatum and C. gloesporioies was selected as a biological control agent for soybean anthracnose. Pseudomonas sp. inhibited the mycelial growth of pathogens effectively as the funhicides such as benomyl and fluazinam in vitro tests without any adverse effects on soybean. Seed treatment with Pseudomonas sp. increased emergence rate of soybean seeds significantly after inoculaton with C. truncatum. When the suspension of Pseudomonas sp. was sprayed on soybean plants, the control efficacy was not different from that of fungicides, benomyl and fluazinam two weeks after treatment, however the efficacy did not last long enough after three weeks.

• Korean Journal of Veterinary Research
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• v.47 no.3
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• pp.303-308
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• 2007

The high mortality (65.5%) of young olive flounder (Paralichthys olivaceus) showing skin ulcers occurred in fish obtained from a commercial cultured farm at Donghae on the eastern coast of Korea at March 2006. The dorsal skin showed ulcer lesions and large amount of mucus. We isolated Ichthyobodo sp. from the gill, and Vibrio anguillarum from the liver and kidney of dead and diseased fish. All of the fish infected with the V anguillarum and Ichthyobodo sp. were treated with 100 ppm formalin for 1 h, and treated with oxolinic acid for 4 h at $22^{\circ}C$, respectively. The formalin treated group was observed the low mortality (2.9%) when compared with high mortality of non-treated (82.9%), and of antibiotic treated group (85.9%) against mixed infections by Vibrio anguillarum and Ichthyobodo sp. organisms. We confirmed complete elimination against mixed infections of Vibrio anguillarum and Ichthyobodo sp. with 100 ppm formalin treatment.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.111-116
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• 2001

Small punch-creep(SP-Creep) test technique has been applied for evaluating the creep characteristics for high temperature materials. However, in order to evaluate the damage and predict the remaining life, it is necessary to establish a quantitative correlation between SP-Creep and uniaxial-creep test results. This paper presents analytical and experimental results of useful correlation between SP-Creep and uniaxial-creep properties for 9Cr1MoVNb steel at $600{\sim}650^{\circ}C$ in terms of stress(load) and activation energy during creep deformation. Especially, the activation energy obtained from SP-Creep test is linearly related to that from uniaxial-creep test at $650^{\circ}C$ as follows: $Q_{sp-p}{\fallingdotseq}1.37\;Q_{TEN},\;Q_{sp-{\sigma}}{\fallingdotseq}1.53\;Q_{TEN}$.

• Research in Plant Disease
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• v.22 no.4
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• pp.243-248
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• 2016

As preventive measures for bonsai exports, nematodes were isolated from 55 bonsai samples of five coniferous species (Chamaecyparis pisifera, Juniperus chinensis, Pinus densiflora, Pinus thunbergii, and Taxus cuspidate) from all 15 bonsai gardens in Korea. Nematodes belonging to 21 genera in 7 orders were isolated from the 55 bonsai samples. Among plant-parasitic nematodes, Tylenchus spp. was the most frequently isolated (14.9%), followed by Ditylenchus spp. (10.5%), Aphelenchoides spp. (9.5%), Aphelenchus sp. (5.5%), Criconemoides sp. (4.0%), Helicotylenchus sp. (0.7%), Hemicycliophora sp. (0.7%), Mesocriconema sp. (0.7%), Tylenchorhynchus sp. (0.7%), and Paratylenchus sp. (0.4%). Among nonparasitic nematodes, Cephalobina was the most frequently isolated nematodes (26.5%), followed by Rhabditida (19.3%), Dorylaimida (17.8%), Pangrolaimida (14.5%), Plectida (6.5%), Tryphylida (6.2%), Mononchida (3.3%), Alaimida (2.9%), Monhysterida (2.5%), and Triplonchida (0.4%). Based on these results, we conclude that there is no problematic plant-parasitic nematode in bonsai gardens of Korea.

• Korean Journal of Plant Resources
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• v.19 no.6
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• pp.660-664
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• 2006

The aerial part of Siegesbeckia pubescens (Compositae) has been used to treat rheumatoid arthritis and hypertension in the Oriental medicine. This crude drug has been used without process (SP-0) or with three times-process of steaming and drying (SP-3) or the nine times of that process (SP-9). To search for the antinociceptive anti-inflammatory components from this crude drug, activity-directed fractionation was performed on this crude drug. Since the $CHCl_3$ extract was shown to have a more potent effect than other extracts, it was subjected to silica gel & ODS column chromatography to yield two diterpene compounds (1). Compound 1 was structurally identified as ent-16 (H, 17-hydroxykauran-19-oic acid, which were tentatively named siegeskaurolic acid A. A main diterpene, siegeskaurolic acid A was tested for the antiiflammatory antinociceptive effects using both hot plate- and writhing anti-nociceptive assays and carrageenan-induced anti-inflammatory assays in mice and rats. Pretreatment with siegeskaurolic acid A (20 and 30mg/kg) significantly reduced the stretching episodes, action time of mice and carrageenan-induced edema. These results support that siegeskaurolic acid is a main diterpene responsible for antinociceptive and antiiflammatory action of S. pubescens. In addition, the assays on SP-0, SP-3 and SP-9 produced the experimental results that SP-9 had more significant effects than other two crude drugs. These results suggest that the processing on the original plant may lead to the higher pharmacological effect.

• Microbiology and Biotechnology Letters
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• v.32 no.2
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• pp.172-178
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• 2004

This research is performed for a biological control of Chinese cabbage clubroot, we isolated an antagonistic bacterium AC-3 against Plasmodiophora sp., causal pathogens of cabbage clubroot. The isolated strain was identified as Streptomyces sp. by culture morphology, biochemical reactions, and homology research based on l6S rDNA sequences. Streptomyces sp. AC-3 produced chitinase (9.3 units/$m\ell$) in culture broth. So Plasmodiophora sp. mycelia changed abnonnal swelling, curling and branching mycelia by Streptomyces sp. AC-3 culture. In a field infected by Plasmodiophora sp., the treatment of a organic fertilizer added 2% Streptomyces sp. AC-3 microbial inoculant, it resulted in about 50% reducing the severity of cabbage clubroot significantly on cabbage plants compared with treated organic fertilizer plants. Additional disease such as sclerotinia rot, fusarium wilt and pythium rot were also significantly reduced by the treatment of the organic fertilizer added Streptomyces sp. AC-3 microbial inoculant.