• KSBB Journal
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• v.23 no.3
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• pp.219-225
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• 2008

For the production of an antifungal compound, one strain (I-8) was selected from approximately 400 strains isolated from various soil samples. The optimum carbon source, nitrogen source and pH culture conditions for the production of the antifungal compound were investigated. ISP No. 2 medium (yeast extract 0.4%, malt extract 1% and dextrose 0.4%, at pH 8) was determined to be the optimum medium. Strain I-8 showed broad antifungal activity against the plant pathogenic fungi tested, including Sclerotinia sclerotiorum KACC 41065, as well as cellulase and chitinase activities in an agar plate assay. The extraction of antifungal compounds was performed using ethyl ether and ethyl acetate. In a culture broth of strain I-8, the ethyl acetate extract exhibited effective growth inhibition against 14 of the 20 phytopathogenic fungi tested. By mixing the ethyl acetate extract from I-8 with the ethyl ether extract from the fungus 13-16, which shows specific antifungal activity against Colletotrichum orbiculare KACC 40808, the antifungal activity of I-8 against phytopathogenic fungi was confirmed to be slightly increased. Strain I-8 showed strong growth inhibition against 16 phytopathogenic strains in agar plate tests.

• BMB Reports
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• v.38 no.1
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• pp.82-88
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• 2005

Bacillus cereus 28-9 is a chitinolytic bacterium isolated from lily plant in Taiwan. This bacterium exhibited biocontrol potential on Botrytis leaf blight of lily as demonstrated by a detached leaf assay and dual culture assay. At least two chitinases (ChiCW and ChiCH) were excreted by B. cereus 28-9. The ChiCW-encoding gene was cloned and moderately expressed in Escherichia coli DH5$\alpha$. Near homogenous ChiCW was obtained from the periplasmic fraction of E. coli cells harboring chiCW by a purification procedure. An in vitro assay showed that the purified ChiCW had inhibitory activity on conidial germination of Botrytis elliptica, a major fungal pathogen of lily leaf blight.

• Journal of Microbiology and Biotechnology
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• v.6 no.6
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• pp.439-444
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• 1996

A bacterial strain, designated as WY22, producing extracellular chitinase was isolated from the soil around the Youngduck area, after enrichment culture in a medium containing $1{\%}$ (w/v) wet colloidal chitin as a sole carbon source. The isolate was identified as a strain of Bacillus sp. based on its morphological and physiological characteristics. It was observed that Bacillus sp. WY22 could inhibit the growth of Fusarium oxysporum with hyphal extention-inhibition assay on potato dextrose agar plate supplemented with $1{\%}$ collidal chitin. Optimum culture conditions of Bacillus sp. WY22 were examined for chitinase production in a chitin medium. High level production of chitinase was observed not only in the chitin medium but in a medium supplemented with $1{\%}$ N-glucosamine or lactose instead of chitin. The optimum concentrations of colloidal chitin and yeast extract were 3.0 and $0.5{\%}$, and the optimum culture conditions for initial pH of medium and temperature were 7.0 and $30^{\circ}C$, respectively, for the production of chitinase.

• Proceedings of the Zoological Society Korea Conference
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• 1998.10b
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• pp.265.1-265
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• 1998

No Abstract, See Full Text

• The Plant Pathology Journal
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• v.33 no.3
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• pp.318-328
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• 2017

Chitinase-producing Paenibacillus elgii strain HOA73 has been used to control plant diseases. However, the antimicrobial activity of its extracellular chitinase has not been fully elucidated. The major extracellular chitinase gene (PeChi68) from strain HOA73 was cloned and expressed in Escherichia coli in this study. This gene had an open reading frame of 2,028 bp, encoding a protein of 675 amino acid residues containing a secretion signal peptide, a chitin-binding domain, two fibronectin type III domains, and a catalytic hydrolase domain. The chitinase (PeChi68) purified from recombinant E. coli exhibited a molecular mass of approximately 68 kDa on SDS-PAGE. Biochemical analysis indicated that optimum temperature for the actitvity of purified chitinase was $50^{\circ}C$. However, it was inactivated with time when it was incubated at $40^{\circ}C$ and $50^{\circ}C$. Its optimum activity was found at pH 7, although its activity was stable when incubated between pH 3 and pH 11. Heavy metals inhibited this chitinase. This purified chitinase completely inhibited spore germination of two Cladosporium isolates and partially inhibited germination of Botrytis cinerea spores. However, it had no effect on the spores of a Colletotricum isolate. These results indicate that the extracellular chitinase produced by P. elgii HOA73 might have function in limiting spore germination of certain fungal pathogens.

• Microbiology and Biotechnology Letters
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• v.20 no.2
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• pp.129-135
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• 1992

A chitinase gene of Serratia marcescens ATCC 27117 was cloned and expressed in Escherichiu di. A genomic library of S, marcescens was constructed with pUC 19 and screened using the swollen chitin agar plate for chitinolytic clones. A positive clone showing chitinclearance contains a recombinant pCHI 89, composed of 8.9 Kb chromosomal DNA fragment and pUC 19. Plasmid pCHI 89 produced 58 KD chitinase in E. coli, which was coincided with one of five extracellular chitinases produced by S. nzarccscens. Restriction endonuclease cleavage sites of the 8.9 Kb insert DNA fragment were mapped. E. coli JM109 harboring pCHI 89 inhibits the growth of a plant pathogenic fungus, Fusarium oxysporum.

• 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.

• Journal of Life Science
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• v.13 no.1
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• pp.90-98
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• 2003

An allium rhizobacterium Serratia plymuthica AL-1 was previously selected as a biocontrol agent of allium white rot. The chitinase from S. plymuthica AL-1 produced in medium containing colloidal chitin was purified by ammonium sulfate precipitation (40~70%), affinity adsorption, column chromatography on DEAE-sephadex A-50 and sephadex C-200 gel filtration. The enzyme was purified 10.8-fold with a yield of 7.3% from the starting culture broth. The purified chtinase gave a single band on sodium dodecyl sulfate polyacrylamide gel electrophoresis, it's molecular weight was estimated to be 55 kDa. The optimum pH and temperature of the purified enzyme were pH 5.5 and $55^{\circ}C$, respectively and it is stable up to $50^{\circ}C$ and maintains around 90% of its activity for 60min. The enzyme were activated by $Ca^{2+}$, $Mn^{2+}$ and $Mg^{2+}$ and inhibited by $Cu^{2+}$, SDS, $\rho$-CMB, MIA, respectively. The purified chitinase showed broad spectrum of antifungal activities against plant pathogenic fungi Sclerotium cepivoruin, Alternana alternnta, Colletotrichum glceosporioidrs, Phoma sp., Sclerotinia sclerotiorum, Stemphylium solani, Fusarium oxysporium f. sp. niveum but rarely inhibited Phytophthora capsici and Pythium ultimum.. The purified chitinase from S. plymuthica AL-1 caused swelling, lysis, deceleration and degradation of the hyphal tips of S. sczerotiorum causing allium white rot. It suggest that S. prymuthica AL-1 chitinase play an important part in the bifunctional chitinase / lysozyme activity.

• Proceedings of the PSK Conference
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• 2001.04a
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• pp.179.1-179.1
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• 2001

• Journal of Microbiology and Biotechnology
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• v.2 no.3
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• pp.209-214
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• 1992

Serratia marcescens co-cultured with various phytopathogenic fungi, including Rhizopus stolonifer, Helminthosporium allii, Pyricularia oryzae, Fusarium oxysporium and Collectothricom cassiicola, in an LB- agar medium containing 1.5% swollen chitin, significantly inhibitied fungal growth. Fungal hyphae grew rapidly outward from the culture dish center, but the hyphal extensions of the pathogenic fungi were significantly inhibited in a perimetric contact area with S. marcescens. This was especially evident in pathogenic fungi which have a high chitin content in their cell walls. The extracellular chitinase activities of S. marcescens were increased seven fold by the addition of 1.5% swollen chitin to the LB-broth, compared to chitinase activities in a culture medium without chitin. The type of induction was dependent on the various forms of chitin used. When the culture supernatant of S. marcescens or the chitinases of Streptomyces griceus purchased from Sigma Chemical Co., were incubated with the mycelium of F. oxysporium, the mycelium gradually burst as cultivation time progressed and completely lysed after incubation for 2 days. On the other hand, E. coli extract did not hydrolyze the F. oxysporium mycelium at all. These data showed that the chitinolytic activities of S. marcescens play important roles in the biochemical control of phytopathogenic fungi.