• Applied Biological Chemistry
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• v.33 no.2
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• pp.154-160
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• 1990

A bacterial strain which was capable of producing extracellular soymilk-clotting enzyme was isolated from soil samples during the course of screening test. The characteristics of the isolated strain K-324-7, indicated that the strain belonged to species of Bacillus cereus. The crude purification of this enzyme was precipitated by salting out with ammonium sulfate of 0.8 saturation. The optimal pH for the enzyme activity was at $6.1{\sim}7.0$ and below $50^{\circ}C$. The optimal culture medium for the production of soymilk-clotting enzyme were consisted of 0.2% glucose, 0.2% peptone, and 0.5% $KH_2PO_4$ with initial pH value of 6.5. The activity of enzyme was maximum when the microbe was cultured for 3 days at $35^{\circ}C$.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.5
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• pp.574-579
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• 1995

To investigate the effect of the midsummer drainage method on growth and lodging characters, Dongjinbyeo was direct seeded on dry paddy field under 4cm of soil depth at May 1 by seeding machine. Three kind of drainage methods were treated such as, once in 20day, towice in 20, 30 days and 3 times 20, 30, 40 days after flooding. As increase the drainage times, the culm and internode length were shorter, culm wall of 4th internode was thicker, breaking weight was heavier, height of center weight was lower, lodging index was reduced, and dry weight of root was increased. Field lodging occured seriously at none drainage but didn't, with two or three times of drainage. Grain yield was not shown significantly different compared with constant flooding irrespective of midsummer drainage times. Therefore two or three times of midsummer drainage could be recommended as the effective water management for the reduction of lodging occurance in direct seeding culture on dry paddy field.

• Journal of Animal Science and Technology
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• v.51 no.6
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• pp.527-536
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• 2009

A potent protein degrading bacterium was isolated from soil samples of different environments. Polyphasic taxonomic studies and phylogenetic 16S rRNA sequence analyses led to identify the isolate IB No. 11 as a strain of Bacillus subtilis. The isolated strain was recognized to produce protease constitutively, and the maximum production (1.64 units/ml) was attained in a shake flask culture when the isolate was grown at $40^{\circ}C$, for 32 h in basal medium supplemented with starch (0.25%) and gelatin (1.25%) as sole carbon and nitrogen source, respectively. The optimum pH and temperature for the protease activity were determined to be pH 7.0 and $50^{\circ}C$, respectively. $Ca^{2+}$ and $Mn^{2+}$ enhanced remarkably the protease activity but neither showed positive effect on the protease's thermal stability. In addition, it was observed that the protease was fairly stable in the pH range of 6.5-8.0 and at temperatures below $50^{\circ}C$, and it could be a good candidate for an animal feed additive. The inhibition profile of the protease by various inhibitors indicated that the enzyme is a member of serine-proteases. A combination of UV irradiation and NTG mutagenesis allowed to develop a protease hyper-producing mutant strain coded as IB No. 11-4. This mutant strain produced approximately 3.23-fold higher protease activity (6.74 units/mg) than the parent strain IB No. 11 when grown at $40^{\circ}C$ for 32h in the production medium. The protease production profile of the selected mutants was also confirmed by the zymography analysis.

• Microbiology and Biotechnology Letters
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• v.31 no.1
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• pp.57-62
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• 2003

A bacteria strain producing extracellular $\beta$-mannanase was isolated from soil and was identified as Bacillus subtilis by 16S rRNA sequence comparison and biochemical determinations. The optimum pH and temperature for the $\beta$-mannanase activity were 5.0 and 5.5$^{\circ}C$, respectively. The zymogram technique revealed a single protein band exhibiting $\beta$-mannanase activity from the culture supernatant. The molecular mass of the enzyme was estimated at approximately 130 kDa. The addition of 0.5% lactose or 0.5% locust bean gum to the LB medium caused to Increase significantly the $\beta$-mannanase productivity from Bacillus subtilis JS-1. The cells grown on LB medium supplemented with lactose produced maximal enzyme activity at the stationary phase. In contrast to this, the $\beta$-mannanase was induced at the logarithmic phase from the cells grown on LB medium supplemented with locust bean gum. The discrepancy in induction times suggests that $\beta$-mannanase was induced by different induction mechanisms depending on the carbon sources in Bacillus subtilis JS-1 .

• Proceedings of the Plant Resources Society of Korea Conference
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• 2000.10a
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• pp.114-115
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• 2000

Aralia elata is found in mountain areas all over Korean peninsula. Aralia elata is the scientific name for Japanese angelica tree. The tree belongs to the family Araliaceae, commonly known as ginseng family. Bud sprouts from apical shoot tip of the plants are rich in flavor and thus mainly used for both folk medicine and vegetable. The stalks with apical buds are gathered in the early spring and planted in sandy soil or water in the greenhouse. The sprouting buds are then collected and sold as fresh vegetable. Although the plants have been used for food, they have been cultivated in a very small scale. In spring, local farmers just go around mountain areas to search the trees and gather the stalks as much as they get and sell them to the market. No conservation efforts have been made to stop the exploitation or to save the dwindling population. We tried to provide local farmers with the plants that may be used as an alternative to stalks from wild populations. This will bel! p conserve the wild populations. However, it is hard to propagate them either by conventional cuttings or by seed germination in a short period of time. Mass propagation using tissue culture systems have shown a great promise with several woody plants. Recently we developed a mass propagation technique via somatic embryogenesis system using mature and/or juvenile explants for Aralia elata. Several factors affecting somatic embryogenesis system including SE(somatic embryo) induction, embryogenic callus proliferation, SE germination, plant regeneration and transplanting to field frill be presented. And some problems arising for the somatic embryogenesis system will be also discussed.

• Korean Journal of Microbiology
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• v.46 no.3
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• pp.286-290
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• 2010

C-1 compounds are observed in anaerobic sediment of high salt environments. Thus, surface sediments and waters from these environments are therefore potential habitats for aerobic methylotrophic microorganisms. The soil samples collected from saltern and tidal flat as inoculums and methanol as carbon and energy source was supplied. After subculture depending on the salt concentration, methanol oxidizing bacteria growth condition investigated, the results of methanol oxidizing bacteria can grow in salt conditions, and the maximum concentration was 20%. Analysis based on denaturing gradient gel electrophoresis of 16S rRNA genes indicates that Methelyophaga-like bacteria were dominants of methylotrophs in the enrichment culture. Quantitative PCR showed that archaeal cells were about 1-10% of bacterial cells. Additionally archaea were assumed not to be involved in methanol oxidation since bacterial antibiotics completely blocked the methanol oxidation. Our results suggest that Methelyophaga-like bacteria could be involved in C-1 compounds oxidation in hypersaline environments although those activities are sensitive to salinity above 20%.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2010.10a
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• pp.18-18
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• 2010

Molecular insights on the role of plant growth promoting rhizobacteria (PGPR) in potato tuberization are reported in the present study. The PGPRwere isolated from the soil collected from potato fields of Highland Agricultural Research Centre, Pyeongchang, Korea and they were identified to the genus level based on the 16S rRNA sequence analysis. These PGPR were heat-killed, filtered and the filtrates were addedindividually at a concentration of $10^7\;cfu\;mL^{-1}$ in MS (Murashige and Skoog's) medium supplemented with 7% (w/v) sucrose to study their influence on in vitro potato tuberization. Tuber initiation occurred early in untreated control, while tuber growth was pronounced in case of PGPR treatments. The control explants showed tuber formation as a result of sub-apical swelling of stolons while several sessile tubers formed directly in the axils of nodal cuttings in case of PGPR treatments, which is an indication of strong induction for tuberization. Theexplants cultured on MS medium supplemented with bacterial isolate 6 (Bacillus firmus strain 40) showed highest average tuber yield (Ca. 12.56 g per treatment) after 30 days of culture, which was 3 folds increase over the untreated control. A significant increase in lipoxygenase (LOX1) mRNA expression and activity of LOX enzyme were also detected in the tubers induced on PGPR treatments as compared to untreated control. This LOX expression level correlated with increased tuber growth and tuber yield. Further studies focused on the role of bacteria cell wall components, growth regulators and signal molecules released by PGPR are under investigation to elicit clues for PGPR-mediated signal pathway controlling potato tuberization.

• Korean Journal of Microbiology
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• v.27 no.1
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• pp.56-62
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• 1989

Antagonistic effects of Streptomyces species aganinst Fusarium solani causing ginseng root rot were investigated in terms of chitinase activity and growth inhibition in vitro. Among 131 isolates of streptomycetes obtained from ginseng cultivating soil, 9 isolates producing large clear zone around the colony on a chitin agar medium were selected for further study. All 9 isolates produced chitinase in a range from 0.10 to 0.38 U lysing cells of F. solani and inhibited germination of the conidia. In the ten-fold condentrated culture filtrate of S. alboniger ST59 and S. roseolilacinus ST129, the number of conidia of F. solane was reduced to about 20% of original count within 14 days. When S. alboniger ST59 and F. solani were grown simultaneously in the mineral saly medium, chitinase activity increased with incubation period, whereas mycelial volume of F. solani decreased. In a chitin added mineral salt medium, chitinase activity increased during the first four days and maintained steady level until the 8th day, and increased thereafter. S. alboniger ST59 lysed mycelia, conidia and even chlamydospores of F. solani. It is probable that the antagonistic activity of this streptomycete against F. solani is the lysis of fungal cell wall by streptomycete producing chitinase affected by antifungal substances.

• Korean Journal of Microbiology
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• v.27 no.1
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• pp.63-69
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• 1989

A pink-pigmented facultative methylotrophic bacterium, Methylobacterium sp. strain SY1, was isolated from soil through methanol-enrichment culture technique. The isolate was gram-negative, slightly curved rod, and motile by a single polarly inserted flagellum. The colony was smooth, bright pink, and slimy. The guanine plus cytosine content of the KNA was 66%. The cell was obigately aerobic and exhibited both catalase and oxidase activities. Carotenoid pigment and poly-$\beta$-hydroxybutyrate were present. It was found to have three kinds of plasmid with molecular weights 45,000, 38,500 and 23,000. Growth with methanol(0.5%) was fast ($t_{d}$=6.5h) and was optimal at $30^{\circ}C$ and at pH 7.0. The isolate could grow on several sugars, organic acids, amino acids, amines, and alcohols in addition to the methanol. Methanol was found to be assimilated through the serine pathway.

• The Korean Journal of Pesticide Science
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• v.3 no.2
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• pp.1-7
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• 1999

The strain with antibacterial activity was isolated among soil samples collected in Suwon area. The isolated strain was identified as Bacillus sp. YR-1 with respect to its morphological, cultural, and physiological characteristics. Optimal medium for the highest production of antibiotic was composed of sucrose 2.0%(w/v), peptone 2.0%(w/v) and NaCl 0.1%(w/v). The maximum production of antibiotic was shown at $35^{\circ}C$ for 48 hours with the initial pH 7.0.