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Dong Jun Seo 大韓遠隔探査學會 1991 大韓遠隔探査學會誌 Vol.7 No.1
An overview is given on stochastic techniques with which remotely sensed data may be used together with ground measurements for purposes of state estimation and prediction. They can explicitly account for spatiotemporal differences in measurement characteristics between ground measurements and remotely sensed data, and are suitable for highly variant space or space-time processes, such as atmospheric processes, which may be viewed as (containing) a random process. For state estimation of static systems, optimal linear estimation is described. As alternatives, various co-kriging estimation techniques are also described, including simple, ordinary, universal, lognormal, disjunctive, indicator, and Bayesian extension to simple and lognormal. For illustrative purposes, very simple examples of optimal linear estimation and simple co-kriging are given. For state estimation and prediction of dynamic systems, distributed-parameter kalman filter is described. Issues concerning actual implementation are given, and areas with application potential are described.
( Dong-jun Seo ),( Woo-jin Jung ) 한국키틴키토산학회 2018 한국키틴키토산학회지 Vol.23 No.2
The expression patterns of chitinase were investigated in tomato after treatment with chitosan, and chitooligosaccharide as an immune-elicitor, with and without the phytopathogen Fusarium oxysporum and antagonist bacterium, Bacillus thuringiensis, in chitosan beads. Chitinase isozymes were shown to have three molecular weights, 25, 65, and 70 kDa, through western blotting with alkaline-phosphatase and horseradish peroxidase-conjugated secondary antibodies. The isoelectric point (pI) ranges of the chitinase isozymes were pI 5-6 (in 65 and 70 kDa) and pI 7.2 (in 25 kDa). The total protein contents were higher at 12 and 24 h in shoots and for the growth period in roots infected with F. oxysporum than those in control plants. The chitinase activity was higher at 12, 24, and 36 h than control plants in tomato roots infected with F. oxysporum. The expression pattern of chitinase was very low in tomato shoots at 24 h after infection with F. oxysporum. The expression patterns of chitinase were much more strongly induced in the roots than the shoots at 24 h after treatment with chitosan, chitosan oligomers, and F. oxysporum. Chitosan activity staining showed the strongest bands at 7 d after F. oxysporum treatment in the shoots and roots. Chitosan activity staining showed strong bands in the treatment with mixed B. thuringiensis GS-2 and chitosan beads in the shoots and roots of tomato. These results indicate that B. thuringiensis GS-2 in chitosan beads could be used as a potential antifungal agent for biological control in agriculture fields.
Recovery of Chitin-Glucan Complex in By-products Obtained from Industrial Yeast Fermentation
( Dong-jun Seo ),( Yong-su Song ),( Gyeong-hyun Jo ),( Chaeyeong Moon ),( Woo-jin Jung ) 한국키틴키토산학회 2020 한국키틴키토산학회지 Vol.25 No.1
Chitin-glucan complex (CGC) copolymer is a cell wall component in fungi and yeasts, used in medicine and cosmetics applications. This study investigated the production of CGC from Aureobasidium pullulans KSY-0516, which is used in the industrial production of β-1,3/1,6-glucan. The amino acid composition of the A. pullulans fermentation by-products was determined using an amino acid analyzer. The total amount of amino acid was 6.67 g/100 g of by-product. Additionally, the recovery of the β-glucan complex from the A. pullulans fermentation by-products was 8.44 g/100 g of by-product using ethanol precipitation. The CGC yield was determined from the by-products after yeast fermentation. The recovery of CGC was 14.83% for the yeast cell wall obtained by alkaline extraction. The CGC and β-glucan were characterized using Fourier transform infrared analysis, and compared with crab shell chitin and laminarin. This study aimed to examine the potential, as a useful substrate for biotechnology, by producing CGC from yeast cultivation by-products.
( Dong Jun Seo ),( Dang Minh Chanh Nguyen ),( Yong Su Song ),( Woo Jin Jung ) 한국미생물 · 생명공학회 2012 Journal of microbiology and biotechnology Vol.22 No.3
An endophytic bacterium, Bacillus thuringiensis GS1, was isolated from bracken (Pteridium aquilinum) and found to have maximal production of chitinase (4.3 units/ml) at 5 days after culture. This study investigated the ability of B. thuringiensis GS1 to induce resistance to Rhizoctonia solani KACC 40111 (RS) in cucumber plants. Chitinase activity was greatest in RS-treated plants at 4 days. β-1,3- Glucanase activity was highest in GS1-treated plants at 5 days. Guaiacol peroxidase (GPOD) activity increased continuously in all treated plants for 5 days. Ascorbate peroxidase (APX) activity in RS-treated plants was increased 1.5-fold compared with the control at 4 days. Polyphenol oxidase (PPO) activity in RS-treated plants was increased 1.5-fold compared with the control at 3 days. At 5 days after treatment, activity staining revealed three bands with chitinase activity (Ch1, Ch2, and Ch3) on SDSPAGE of cucumber plants treated with GS1+RS, whereas only one band was observed for RS-treated plants (Ch2). One GPOD isozyme (Gp1) was also observed in response to treatment with RS and GS1+RS at 4 days. One APX band (Ap2) was present on the native-PAGE gel of the control, and GS1- and GS1+RS-treated plants at 1 day. PPO bands (Po1 and Po2) from RS- and GS1+RS-treated plants were stronger than in the control and GS1-treated plants upon native-PAGE at 5 days. Taken together, these results indicate that the induction of PR proteins and defense-related enzymes by B. thuringiensis GS1 might have suppressed the damping-off caused by R. solani KACC 40111 in cucumber plants.
( Dong Jun Seo ),( Min Jin Choi ),( Yong Su Song ),( Dang Minh Chanh Nguyen ),( Woo Jin Jung ) 한국키틴키토산학회 2010 한국키틴키토산학회지 Vol.15 No.3
A rhizosphere bacterium having strong chitinolytic activity on 0.5% colloidal chitin-containing agar medium was isolated from soil in Canada. Based on the nucleotide sequence of a conserved segment of a 16S rRNA gene, the bacterium was identified as Bacillus cereus M1K. Chitinase activity staining of B. cereus M1K was investigated in 12% SDS-PAGE containing 0.01% glycol chitin as a substrate. Active bands of the chitinase isozymes expressed from B. cereus M1K were observed as three bands (56, 48 and 37 kDa) on SDS-PAGE gel. B. cereus M1K was showed antifungal activity against phytopathogens both Rhizoctonia solani KACC 40111 and Fusarium solani KACC 40384. This study was investigated the ability of B. cereus M1K to induce resistance against R. solani KACC 40111 in cucumber plants. Chitinase of 40 kDa was induced by antagonist B. cereus M1K, and chitinase of 35 and 40 kDa was induced by phytopathogen R. solani KACC 40111. These results indicate that the chitinase produced by B. cereus M1K plays an important role in the biocontrol of soil borne phytopathogen.
Dong Jun Seo,Yong Su Song,Dang Minh Chanh Nguyen,Kil Yong Kim,Ro Dong Park,Woo Jin Jung 한국키틴키토산학회 2013 한국키틴키토산학회지 Vol.18 No.1
In this study, chitosan beads combined with Corni fructus (Cornus officinalis) seeds were used as an antifungal agent for phytopathogens. Antifungal activity was measured on R. solani, F. solani, F. oxysporum, and S. sclerotiorum with four different treatments: Corni fructus seeds (CFS), chitosan (CTS), Corni fructus seeds + chitosan (CFS + CTS), and acetic acid (AA). CFS + CTS showed the highest activity based on the EC50 (1.23%) and MIC90 (2.22%) for fungicidal activity of R. solani, while CTS resulted in higher values of EC50 (1.42%) and MIC90 (6.26%). Treatment of CFS + CTS was the highest efficiency value of 51.19 at fungicidal activity of F. solani. The inhibition rate of chitosan beads at pH 3.8 was 100% and 43.5% in R. solani and S. sclerotiorum, respectively. 83% of Kale seedlings were infected at 4 days and 100% at 5 days after treatment of R. solani. Kale seedlings were slightly infected at 3 days, rising to 50% at 5 days after treatment with chitosan beads and R. solani. These results indicate that this bioorganic substance has a great potential as an alternative to synthetic fungicides for the control of plant pathogens.
Properties of Enzymes Produced from Antagonistic Bacterium Bacillus thuringiensis GS-2
( Dong-jun Seo ),( Wan Taek Ju ),( Kil Yong Kim ),( Woo Jin Jung ) 한국키틴키토산학회 2015 한국키틴키토산학회지 Vol.20 No.3
Bacillus thuringiensis GS-2 was incubated on various culture media to investigate the concurrent expression patterns of chitinase and chitosanase isozymes by SDS-PAGE. Chitinase activity increased rapidly with a maximum level (11 units/mL) after 5 days of incubation in colloidal chitin medium. B. thuringiensis GS-2 had strong antifungal activity on PDA medium for Rhizoctonia solani and Fusarium oxysporum. Four chitinase isozymes were expressed on the SDS-PAGE gel as active bands (about 70, 65, 37, and 35 kDa) on LB medium after incubation. The chitosanase isozyme of 39 kDa was expressed strongly on the SDSPAGE gel in LB medium and was expressed lightly on the SDS-PAGE gel after incubation in 0.5% chitosan powder and 0.5% chitosan beads medium. Four chitinase isozymes (C1, C2, C3, and C4) were expressed on 2-D gel at 5 h and 12 h after incubation. Three chitinase isozymes (C1, C3, and C4) were expressed on 2-D gel at 1 h and 2 h after incubation. Isoelectric point (pI) of chitinase isozymes was range from 3.5 to 9.